leukotriene-b4 and Inflammation

Besides smoking, lung cancer can be caused by other factors, including heavy metals such as cadmium, nickel, arsenic, beryllium and hexavalent chromium [Cr(VI)], which is used in multiple settings, resulting in widespread environmental and occupational exposures as well as heavy use. The mechanism by which Cr(VI) causes lung cancer is not completely understood. Currently, it is admitted chromosome instability is a key process in the mechanism of Cr(VI)-induced cancer, and previous studies have suggested Cr(VI) impacts the lung tissue in mice by triggering tissue damage and inflammation. However, the mechanism underlying Cr(VI)-induced inflammation and its exact role in lung cancer are unclear. Therefore, this review aimed to systematically examine previous studies assessing Cr(VI)-induced inflammation and to summarize the major inflammatory pathways involved in Cr(VI)-induced inflammation. In cell culture studies, COX2, VEGF, JAK-STAT, leukotriene B4 (LTB4), MAPK, NF-ҡB and Nrf2 signaling pathways were consistently upregulated by Cr(VI), clearly demonstrating that these pathways are involved in Cr(VI)-induced inflammation. In addition, Akt signaling was also shown to contribute to Cr(VI)-induced inflammation, although discrepant findings were reported. Few mechanistic studies were performed in animal models, in which Cr(VI) upregulated oxidative pathways, NF-kB signaling and the MAPK pathway in the lung tissue. Similar to cell culture studies, opposite effects of Cr(VI) on Akt signaling were reported. This work provides insights into the mechanisms by which Cr(VI) induces lung inflammation. However, discrepant findings and other major issues in study design, both in cell and animal models, suggest that further studies are required to unveil the mechanism of Cr(VI)-induced inflammation and its role in lung cancer.

Topics: Animals; Arsenic; Beryllium; Cadmium; Chromium; Cyclooxygenase 2; Inflammation; Leukotriene B4; Lung; Lung Neoplasms; Mice; NF-E2-Related Factor 2; NF-kappa B; Nickel; Proto-Oncogene Proteins c-akt; Vascular Endothelial Growth Factor A

Arachidonic acid (AA) metabolism is critical in the initiation and resolution of inflammation. Prostaglandin E2 (PGE2) and leukotriene B4/D4/E4 (LTB4/LD4/LTE4), derived from AA, are involved in the initiation of inflammation and regulation of immune response, hematopoiesis, and M1 (pro-inflammatory) macrophage facilitation. Paradoxically, PGE2 suppresses interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) production and triggers the production of lipoxin A4 (LXA4) from AA to initiate inflammation resolution process and augment regeneration of tissues. LXA4 suppresses PGE2 and LTs' synthesis and action and facilitates M2 macrophage generation to resolve inflammation. AA inactivates enveloped viruses including SARS-CoV-2. Macrophages, NK cells, T cells, and other immunocytes release AA and other bioactive lipids to produce their anti-microbial actions. AA, PGE2, and LXA4 have cytoprotective actions, regulate nitric oxide generation, and are critical to maintain cell shape and control cell motility and phagocytosis, and inflammation, immunity, and anti-microbial actions. Hence, it is proposed that AA plays a crucial role in the pathobiology of ischemia/reperfusion injury, sepsis, COVID-19, and other critical illnesses, implying that its (AA) administration may be of significant benefit in the prevention and amelioration of these diseases.

Topics: Animals; COVID-19; Dinoprostone; Fatty Acids, Essential; Humans; Inflammation; Leukotriene B4; Lipoxins; SARS-CoV-2

Type I hypersensitivity is an immediate immune reaction that involves IgE-mediated activation of mast cells. Activated mast cells release chemical mediators, such as histamine and lipid mediators, which cause allergic reactions. Recent developments in detection devices have revealed that mast cells simultaneously release a wide variety of lipid mediators. Mounting evidence has revealed that mast cell-derived mediators exert both pro- and anti-inflammatory functions and positively and negatively regulate the development of allergic inflammation. This review presents the roles of major lipid mediators released from mast cells. Author believes this review will be helpful for a better understanding of the pathogenesis of allergic diseases and provide a new strategy for the diagnosis and treatment of allergic reactions.

Topics: Fatty Acids, Unsaturated; Histamine Release; Humans; Hydroxyeicosatetraenoic Acids; Hypersensitivity, Immediate; Immunoglobulin E; Inflammation; Leukotriene B4; Leukotriene C4; Lipid Metabolism; Mast Cells; Prostaglandin D2

Leukotriene B4 (LTB4) is a major type of lipid mediator that is rapidly generated from arachidonic acid through sequential action of 5-lipoxygenase (5-LO), 5-lipoxygenase-activating protein (FLAP) and LTA4 hydrolase (LTA4H) in response to various stimuli. LTB4 is well known to be a chemoattractant for leukocytes, particularly neutrophils, via interaction with its high-affinity receptor BLT1. Extensive attention has been paid to the role of the LTB4-BLT1 axis in acute and chronic inflammatory diseases, such as infectious diseases, allergy, autoimmune diseases, and metabolic disease via mediating recruitment and/or activation of different types of inflammatory cells depending on different stages or the nature of inflammatory response. Recent studies also demonstrated that LTB4 acts on non-immune cells via BLT1 to initiate and/or amplify pathological inflammation in various tissues. In addition, emerging evidence reveals a complex role of the LTB4-BLT1 axis in cancer, either tumor-inhibitory or tumor-promoting, depending on the different target cells. In this review, we summarize both established understanding and the most recent progress in our knowledge about the LTB4-BLT1 axis in host defense, inflammatory diseases and cancer.

Topics: Animals; Disease; Health; Humans; Inflammation; Leukotriene B4; Neoplasms; Receptors, Leukotriene B4

Leukotriene B

Topics: Animals; Eye; Eye Diseases; Humans; Inflammation; Leukotriene B4; Receptors, Leukotriene B4

Eicosanoids and specialized proresolving mediators (SPMs) regulate leukocyte function and inflammation. They are ideally positioned at the interface of the innate and adaptive immune responses when lymphocytes interact with leukocytes. Receptors for leukotriene B

Topics: Animals; Dinoprostone; Eicosanoids; Humans; Inflammation; Leukotriene B4; Lymphocytes

Galectin-3 and LTB

Topics: Animals; Anti-Inflammatory Agents; Galectin 3; Humans; Inflammation; Insulin; Insulin Resistance; Leukotriene B4; Obesity

Directed leukocyte migration is a hallmark of inflammatory immune responses. Leukotrienes are derived from arachidonic acid and represent a class of potent lipid mediators of leukocyte migration. In this review, we summarize the essential steps leading to the production of LTB

Topics: Animals; Cell Movement; Chemotaxis; Humans; Inflammation; Leukocytes; Leukotriene B4; Neutrophils; Receptors, Leukotriene B4; Signal Transduction

The ability to regulate inflammatory pathways and host defense mechanisms is critical for maintaining homeostasis and responding to infections and tissue injury. While unbalanced inflammation is detrimental to the host; inadequate inflammation might not provide effective signals required to eliminate pathogens. On the other hand, aberrant inflammation could result in organ damage and impair host defense. The lipid mediator leukotriene B

Topics: Animals; Cell Movement; Homeostasis; Humans; Immunity, Innate; Immunomodulation; Inflammation; Leukotriene B4; Neutrophils; Phagocytosis

Inflammatory arthritis, including rheumatoid arthritis (RA), is characterized by infiltration of inflammatory cells into the joints. Biological agents targeting TNF-α and IL-6 dramatically improve RA. However, some RA patients do not respond to current treatments and these broadly active upstream biological agents increase the risk of severe infection. Therefore, there remains a need for other effective and safe treatments for RA. Many studies have implicated that blockade of leukotriene B4 (LTB

Topics: Animals; Arthritis; Arthritis, Rheumatoid; Clinical Trials as Topic; Disease Models, Animal; Humans; Inflammation; Leukotriene B4; Molecular Targeted Therapy; Receptors, Leukotriene B4

As the first line of innate immune defense, neutrophils need to mount a rapid and robust antimicrobial response. Recent studies implicate various positive feedback amplification processes in achieving that goal. Feedback amplification ensures effective migration of neutrophils in shallow chemotactic gradients, multiple waves of neutrophil recruitment to the site of inflammation, and the augmentation of various effector functions of the cells. We review here such positive feedback loops including intracellular and autocrine processes, paracrine effects mediated by lipid (LTB4), chemokine, and cytokine mediators, and bidirectional interactions with the complement system and with other immune and non-immune cells. These amplification mechanisms are not only involved in antimicrobial immunity but also contribute to neutrophil-mediated tissue damage under pathological conditions.

Topics: Animals; Cell Communication; Chemotaxis; Complement System Proteins; Feedback, Physiological; Humans; Immunity, Innate; Infections; Inflammation; Leukotriene B4; Neutrophil Activation; Neutrophils

Leishmaniasis is a vector-borne disease that affects several populations worldwide, against which there are no vaccines available and the chemotherapy is highly toxic. Depending on the species causing the infection, the disease is characterized by commitment of tissues, including the skin, mucous membranes, and internal organs. Despite the relevance of host inflammatory mediators on parasite burden control, Leishmania and host immune cells interaction may generate an exacerbated proinflammatory response that plays an important role in the development of leishmaniasis clinical manifestations. Plant-derived natural products have been recognized as bioactive agents with several properties, including anti-protozoal and anti-inflammatory activities. The present review focuses on the antileishmanial activity of plant-derived natural products that are able to modulate the inflammatory response in vitro and in vivo. The capability of crude extracts and some isolated substances in promoting an anti-inflammatory response during Leishmania infection may be used as part of an effective strategy to fight the disease.

Topics: Animals; Anti-Inflammatory Agents; Antineoplastic Agents; Biological Products; Cell Communication; Cytokines; Drug Design; Humans; Inflammation; Leishmania; Leishmaniasis; Leukotriene B4; Plant Extracts

Crohn's disease (CD) is characterized by transmural inflammation that is most frequently located in the region of the terminal ileum. Although the physiopathological mechanisms of the disease are not yet well defined, the unregulated immune response is associated with high production of reactive oxygen species (ROS). These elements are associated with complex systems known as antioxidant defenses, whose function is ROS regulation, thereby preventing the harmful effects of these elements. However, the presence of an imbalance between ROS production and ROS elimination by antioxidants has been widely described and leads to oxidative stress. In this article, we describe the most significant findings on oxidative stress in the intestinal mucosa and peripheral blood.

Topics: Anti-Inflammatory Agents; Autoantibodies; Catalase; Crohn Disease; Humans; Hydrogen Peroxide; Inflammation; Intestinal Mucosa; Leukotriene B4; Lymphocytes; NADPH Oxidases; Neutrophils; Nitric Oxide Synthase Type II; Oxidative Stress; PPAR gamma; Probiotics; Reactive Nitrogen Species; Reactive Oxygen Species

Chemoattractants are pivotal mediators of host defense, orchestrating the recruitment of immune cells into sites of infection and inflammation. Chemoattractants display vast chemical diversity and include bioactive lipids, proteolytic fragments of serum proteins, and chemokines (chemotactic cytokines). All chemoattractants induce chemotaxis by activating seven-transmembrane-spanning GPCRs expressed on immune cells, establishing the concept that all chemoattractants are related in function. However, although chemoattractants have overlapping functions in vitro, recent in vivo data have revealed that they function, in many cases, nonredundantly in vivo. The chemically diverse nature of chemoattractants contributes to the fine control of leukocyte trafficking in vivo, with sequential chemoattractant use guiding immune cell recruitment into inflammatory sites. Lipid mediators frequently function as initiators of leukocyte recruitment, attracting the first immune cells into tissues. These initial responding immune cells produce cytokines locally, which in turn, induce the local release of chemokines. Local chemokine production then markedly amplifies subsequent waves of leukocyte recruitment. These new discoveries establish a paradigm for leukocyte recruitment in inflammation--described as lipid-cytokine-chemokine cascades--as a driving force in the effector phase of immune responses.

Topics: Animals; Arthritis, Experimental; Asthma; Chemokines; Chemotactic Factors; Chemotaxis, Leukocyte; Cytokines; Gene Expression Regulation; Humans; Inflammation; Inflammation Mediators; Leukocytes; Leukotriene B4; Lipids; Mice; Neutrophils; Receptors, G-Protein-Coupled; Receptors, Leukotriene B4; Signal Transduction; Th2 Cells

Neutrophil dysfunction has been documented after injury in animals and human beings. This review evaluates the relative effects of the hormonal and endotoxin response to injury on immune resistance.. Review of the pertinent English-language literature.. In volunteers given total parenteral nutrition, neutrophils demonstrate a robust response to leukotriene B4 but none to zymosan/activated serum or the bacterial metabolite formyl-methionyl-leucyl-phenylalanine (FMLP). This finding suggests subclinical exposure to activated complement and FMLP that does not occur during enteral feeding. Additional evidence of neutrophil activation is the release of lactoferrin to the same degree with the two routes of feeding. When normal volunteers are challenged with endotoxin, uniform impairment of the neutrophil response to chemotactic stimuli except LTB4 is demonstrated. Epinephrine increases the total circulating neutrophil pool for a few hours, whereas when cortisol is administered, the neutrophil counts continue to increase through 6 h. A combined epinephrine and cortisol infusion extends the half-life of neutrophils. The role of genomic and central nervous system control through the vagus nerve also is reviewed.. Normal volunteers have provided insight into the stress response to infection that is understood only partially.

Topics: Animals; Endotoxins; Epinephrine; Humans; Hydrocortisone; Immunity, Humoral; Inflammation; Leukotriene B4; Models, Biological; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Nutritional Support; Zymosan

Mammals have at least two receptors for LTB4; high-affinity BLT1 and low-affinity BLT2, both of which are GPCRs. 12-HHT serves as a more potent and abundant ligand for BLT2 than LTB4. BLT1 is expressed in a variety of inflammatory and immune cells including granulocytes, eosinophils, macrophages, differentiated Th1, Th2 and Th17 cells, effecter CD8+ T cells, dendritic cells and osteoclasts. BLT1 antagonists will be beneficial for the treatment of various diseases such as bronchial asthma, multiple sclerosis, contact dermatitis, and postmenopausal osteoporosis. BLT2 plays different roles from BLT1, and one important role of BLT2 is the maintenance of mucosal integrity in the colon.

Topics: Animals; Arachidonic Acid; Dendritic Cells; Humans; Inflammation; Leukotriene B4; Molecular Structure; Osteoclasts; Receptors, Leukotriene B4; T-Lymphocytes

Leukotriene A4 hydrolase (LTA4H) is a ubiquitously expressed enzyme that catalyzes the final step in the synthesis of leukotriene B4 (LTB4), a potent proinflammatory lipid mediator derived from arachidonic acid. Although LTB4 was identified 30 years ago, several recent findings have refocused attention on this mediator as a target for inflammatory and autoimmune diseases. While LTB4 was once thought to be a chemoattractant and activator only of leukocytes mediating acute, innate inflammatory responses, LTB4 receptors have since been discovered on multiple cell types, including T-lymphocytes and antigen-presenting dendritic cells. Thus, the inhibition of LTB4 synthesis demonstrates potential for targeting chronic, autoimmune-driven inflammation. In addition to genetic data in animals and humans linking the LTB4 pathway to cardiovascular disease, variants in the LTA4H gene have been linked with susceptibility to asthma. Several companies have initiated drug discovery efforts to identify potent, selective LTA4H inhibitors. Selected molecules have demonstrated oral efficacy in preclinical models of asthma, inflammatory bowel disease and arthritis, suggesting therapeutic potential for multiple indications. This review focuses on developments with therapeutic relevance for inhibitors of LTA4H as anti-inflammatory drugs, and particularly in the treatment of respiratory disease.

Topics: Animals; Anti-Inflammatory Agents; Autoimmune Diseases; Dendritic Cells; Drug Design; Enzyme Inhibitors; Epoxide Hydrolases; Humans; Inflammation; Leukotriene B4; Respiratory Tract Diseases; T-Lymphocytes

Chalcones are a group of phenolic compounds which possess a wide variety of cytoprotective and modulatory functions. They have been shown to possess antioxidant, oxygen scavenging and anti-inflammatory properties in a variety of experimental systems and can trigger the intracellular cascade of protective pathways offering a promising stratagem for therapeutic applications. In this research we will review the anti-inflammatory effect of chalcone derivatives and new approaches.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Chalcones; Chemistry, Pharmaceutical; Drug Design; Free Radical Scavengers; Humans; Inflammation; Leukotriene B4; Models, Biological; Models, Chemical; Neutrophils; Oxygen; Phenol

LTB4, a proinflammatory lipid mediator generated from arachidonic acid through the action of 5-lipoxygenase, has been known for over two decades and is implicated in a wide variety of inflammatory disorders. BLT1, a G-protein-coupled receptor, has recently been identified as a high affinity receptor specific for LTB4. Recent studies in allergen-induced airway hyperresponsiveness and inflammation using mice lacking BLT1 have shown crucial new roles for leukotriene B4 and BLT1 in Th2 cytokine IL-13 production from lung T cells and recruitment of antigen-specific effector CD8+ T cells, suggesting novel mechanisms for their actions. The leukotriene B4-BLT1 pathway is an important target for the treatment of bronchial asthma.

Topics: Allergens; Animals; Humans; Inflammation; Leukotriene B4; Receptors, Leukotriene B4; Respiratory Hypersensitivity; Signal Transduction

Topics: Aged; Animals; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Receptors, Leukotriene B4

Topics: Acne Vulgaris; Androgens; Dermatitis, Seborrheic; Genetic Predisposition to Disease; Gram-Positive Bacterial Infections; Humans; Inflammation; Leukotriene B4; Propionibacterium acnes; Sebum; Stress, Psychological

Topics: Animals; Arachidonic Acids; Cloning, Molecular; Humans; Inflammation; Leukotriene B4; Ligands; Mice; Receptors, Cytoplasmic and Nuclear; Receptors, Leukotriene B4; Signal Transduction; Transcription Factors

Many antiinflammatory pharmaceutical products inhibit the production of certain eicosanoids and cytokines and it is here that possibilities exist for therapies that incorporate n-3 and n-9 dietary fatty acids. The proinflammatory eicosanoids prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)) are derived from the n-6 fatty acid arachidonic acid (AA), which is maintained at high cellular concentrations by the high n-6 and low n-3 polyunsaturated fatty acid content of the modern Western diet. Flaxseed oil contains the 18-carbon n-3 fatty acid alpha-linolenic acid, which can be converted after ingestion to the 20-carbon n-3 fatty acid eicosapentaenoic acid (EPA). Fish oils contain both 20- and 22-carbon n-3 fatty acids, EPA and docosahexaenoic acid. EPA can act as a competitive inhibitor of AA conversion to PGE(2) and LTB(4), and decreased synthesis of one or both of these eicosanoids has been observed after inclusion of flaxseed oil or fish oil in the diet. Analogous to the effect of n-3 fatty acids, inclusion of the 20-carbon n-9 fatty acid eicosatrienoic acid in the diet also results in decreased synthesis of LTB(4). Regarding the proinflammatory ctyokines, tumor necrosis factor alpha and interleukin 1beta, studies of healthy volunteers and rheumatoid arthritis patients have shown < or = 90% inhibition of cytokine production after dietary supplementation with fish oil. Use of flaxseed oil in domestic food preparation also reduced production of these cytokines. Novel antiinflammatory therapies can be developed that take advantage of positive interactions between the dietary fats and existing or newly developed pharmaceutical products.

Topics: alpha-Linolenic Acid; Arachidonic Acid; Arthritis, Rheumatoid; Dietary Fats; Dinoprostone; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; Female; Fish Oils; Humans; Inflammation; Inflammation Mediators; Interleukin-1; Leukotriene B4; Linseed Oil; Male; Tumor Necrosis Factor-alpha

Leukotriene B4 is a pro-inflammatory mediator synthesised in myeloid cells from arachidonic acid. Synthesis is catalysed by 5-lipoxygenase and leukotriene A4 hydrolase and is increased by inflammatory mediators including endotoxin, complement fragments, tumor necrosis factor and interleukins. A nuclear membrane protein, 5-lipoxygenase activating protein, is an essential co-factor for 5-lipoxygenase. Leukotriene B4 induces recruitment and activation of neutrophils, monocytes and eosinophils. It also stimulates the production of a number of proinflammatory cytokines and mediators indicating an ability to augment and prolong tissue inflammation. Elevated levels of leukotriene B4 have been found in a number of inflammatory diseases and levels are related to disease activity in some of these. Initial data from pharmacological inhibition studies support a role for leukotriene B4 in the pathogenesis of neutrophil mediated tissue damage, and treatments which reduce its production or block its effects may prove beneficial in neutrophil mediated inflammatory diseases.

Topics: Arachidonate 5-Lipoxygenase; Cytokines; Humans; Inflammation; Inflammation Mediators; Leukotriene B4; Lipoxygenase Inhibitors; Neutrophil Activation; Neutrophils; Receptors, Cell Surface; Shock, Septic

Leukotrienes are potent pro-inflammatory mediators that appear to contribute to pathophysiologic features of asthma. For example, cysteinyl leukotrienes contract airway smooth muscle, increase microvascular permeability, stimulate mucus secretion, decrease mucociliary clearance, and appear capable of recruiting eosinophils into the airways. Segmental antigen bronchoprovocation in patients with asthma increases LTC4 concentrations in bronchoalveolar lavage fluid, which correlates with an influx of eosinophils into the airways. LTB4, in comparison, selectively affects neutrophil functions. Intratracheal instillation of LTB4 produced a selective recruitment of neutrophils into the lung. These effects suggest that leukotrienes contribute significantly to the inflammatory components of asthma.

Topics: Animals; Asthma; Bronchoalveolar Lavage Fluid; Cysteine; Humans; Inflammation; Leukotriene B4; Leukotrienes; SRS-A

Deposition of immune complexes in tissues is the pathogenic mechanism underlying tissue injury in a number of diverse clinical conditions affecting the skin, joints, blood vessels and renal glomeruli. Initial approaches to the understanding of these conditions have stressed the roles of both the activation of the complement system and the accumulation of polymorphonuclear leukocytes as the main molecular and cellular mechanisms explaining the sequence of events leading to tissue damage. Recent findings on (i) the molecular biology of the leukocyte chemoattractants, (ii) the chemical structure and function of receptors for the Fc portion of the antibody molecule and (iii) the signaling events coupled to the engagement of these receptors have led to an understanding of the biochemical events involved in immune-complex injury and have provided a promising avenue for the development of therapeutic approaches. This review will focus on our current understanding of signal transduction events in the effector phase of immune-complex-mediated tissue injury.

Topics: Anaphylatoxins; Animals; Calcium-Calmodulin-Dependent Protein Kinases; Chemokines; Chemotactic Factors; Dinoprostone; GTP-Binding Proteins; Immunoglobulin G; Inflammation; Leukocytes; Leukotriene B4; Leukotrienes; Lipids; Mice; Models, Biological; NF-kappa B; Phagocytes; Phospholipases A; Platelet Activating Factor; Signal Transduction; Thromboxane A2

Polymorphonuclear leukocytes (neutrophils) are recruited to inflammatory sites by a variety of soluble mediators (chemoattractants) that stimulate neutrophil directed migration (chemotaxis). Many neutrophil chemoattractants such as neutrophil activating proteins, leukotriene B4 (LTB4), platelet activating factor, and complement-derived C5a, are generated endogenously by host cells or enzymatic cleavage of host proteins. Other chemoattractants such as N-formyl peptides are generated exogenously by bacteria that invade the host. Oxidative modification of methionine residues or changes in the amino acid sequence of peptide chemoattractants dramatically alter their chemoattractive properties. Many of the well-defined neutrophil chemotactic factors and studies of their structure-function relationships will be reviewed.

Topics: Animals; Chemotactic Factors; Chemotaxis, Leukocyte; Complement C5a; Humans; Inflammation; Leukotriene B4; Neuropeptides; Neutrophils; Platelet Activating Factor; Platelet Factor 4

Topics: Allergens; Animals; Arachidonic Acids; Bronchoconstriction; Humans; Inflammation; Leukotriene B4; Lipoxygenase; Lung

Topics: Animals; Cytokines; Humans; Inflammation; Interferon-gamma; Interleukin-1; Interleukin-6; Leukotriene B4; Macrophages; Models, Biological; Monocytes; Platelet Activating Factor; Tumor Necrosis Factor-alpha

Topics: Eicosanoids; Fatty Acids, Essential; Humans; Inflammation; Leukotriene B4; Linoleic Acid; Linoleic Acids; Neutrophils

Topics: Animals; Fatty Acids; Humans; Inflammation; Leukocytes; Leukotriene B4; Lymphocytes; Receptors, Immunologic; Receptors, Leukotriene B4

Topics: Arachidonate 5-Lipoxygenase; Arachidonate Lipoxygenases; Epoxide Hydrolases; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Leukotrienes; SRS-A

The potent mediators generated by the 5- and 15-lipoxygenation of arachidonic acid have diverse effects on smooth muscles, blood vessels, leukocytes, epithelial cells and glands, and sensory neurons, which suggest possible roles in the initiation and regulation of physiological and biochemical events. The responses to leukotrienes and related mediators are attributable to binding by stereospecific cellular receptors and consequent activation of biochemical transductional sequences analogous to those characteristic of other receptor systems. The elevated concentrations of these mediators in lesional fluids and tissues of inflammatory bowel disease and other hypersensitivity and inflammatory states are, in some instances, clearly related to the time course of development of the disease process. Systematic application of specific inhibitors and antagonists that are becoming available will define more clearly the involvement of leukotrienes in health and disease and possibly lead to new therapeutic approaches.

Topics: Arachidonate 15-Lipoxygenase; Arachidonate 5-Lipoxygenase; Colitis, Ulcerative; Crohn Disease; Humans; Hypersensitivity; Inflammation; Leukotriene B4; SRS-A

Topics: Arachidonic Acids; Bacterial Infections; Bacterial Toxins; Calcium; Fatty Acids, Unsaturated; Humans; Immunity, Cellular; Inflammation; Leukotriene B4; Lymphocyte Activation; Neutrophils; Prostaglandins E; SRS-A; Superoxides

Topics: Animals; Bradykinin; Capillary Permeability; Complement C5; Complement C5a; Histamine; Humans; Inflammation; Leukotriene B4; Lung; Neuropeptides; Platelet Activating Factor; Prostaglandins; SRS-A

Topics: Acute Disease; Animals; Humans; Inflammation; Leukotriene B4; Neutrophils; Respiratory Distress Syndrome; Sheep; SRS-A; Tetradecanoylphorbol Acetate; Vasoconstriction

In conclusion, we have described a novel series of acetohydroxamic acids that are potent and selective inhibitors of arachidonate 5-lipoxygenase in vitro and in vivo. In addition, we have shown that these compounds attenuate "leukotriene-dependent" anaphylactic bronchospasm, the accumulation of inflammatory leukocytes, and the development of fever in experimental models. It now remains to be determined if these compounds have any therapeutic value in man.

Topics: 5,8,11,14-Eicosatetraynoic Acid; Anaphylaxis; Animals; Arachidonate 5-Lipoxygenase; Arachidonate Lipoxygenases; Arachidonic Acid; Arachidonic Acids; Bronchial Provocation Tests; Bronchial Spasm; Fever; Gastric Mucosa; Guinea Pigs; Humans; Hydroxamic Acids; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Masoprocol; Rats; SRS-A

Topics: Asthma; Basophils; Cell Communication; Endothelium, Vascular; Eosinophils; Humans; Inflammation; Leukotriene B4; Leukotriene E4; Mast Cells; SRS-A

Topics: Arachidonate 5-Lipoxygenase; Arachidonic Acid; Arachidonic Acids; Chemotaxis, Leukocyte; Dietary Fats; Fatty Acids; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Lymphocyte Activation; Neutrophils; Receptors, Immunologic; Receptors, Leukotriene; Receptors, Leukotriene B4; Receptors, Prostaglandin; SRS-A

Polymorphonuclear leukocytes (PMNL) are prominent at sites of acute inflammation. Their infiltration is stimulated under pathological conditions by a variety of agents which include bacteria, immune complexes and complement derived chemotactic peptides. Recently attention was focussed on the 5-lipoxygenase product leukotriene B4 (LTB4) which has been demonstrated to induce the key features associated with an acute inflammatory reaction. However, evidence supporting a pro-inflammatory role for LTB4, and therefore the anti-inflammatory efficacy of 5-lipoxygenase inhibitors, is largely circumstantial. Moreover, there are concerns that other chemotactic factors, notably C5a, may compensate for the absence of LTB4. Here we challenge this view and, on the basis of recent experimental and clinical data suggest that LTB4 does not simply duplicate the activity of C5a. Instead we propose that their predominant site(s) of action differ in such a way that they may synergise in mediating PMNL recruitment.

Topics: Animals; Humans; Inflammation; Leukotriene B4; Neutrophils; Rabbits

Topics: Animals; Humans; Inflammation; Leukotriene B4; Lipoxygenase; Prostaglandin-Endoperoxide Synthases; Prostaglandins; SRS-A

Topics: Animals; Cardiovascular System; Humans; Inflammation; Leukotriene B4; Respiratory System; SRS-A

Many mediators of inflammation are derived from phospholipids and polyunsaturated fatty acids, including prostaglandins, leukotrienes, and platelet-activating factor. These mediators augment the vascular phase of inflammation and modify functions of inflammatory cells and cells of the immune system. Several growth factors or cytokines augment production of prostaglandin synthesis. The production of lipid-derived mediators may be inhibited by anti-inflammatory drugs and by modifying dietary polyunsaturated fatty acids.

Topics: Humans; Inflammation; Leukotriene B4; Lipid Metabolism; Lipids; Prostaglandins; SRS-A

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Blood Cells; Cells, Cultured; Free Radicals; Glomerulonephritis; Humans; Inflammation; Kidney Glomerulus; Leukotriene B4; Lipoxygenase; Membrane Lipids; Oxygen; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Rats; SRS-A; Thromboxanes

A survey is given of the immunomodulatory effects of interferon gamma (IFN-gamma) in inflammation. IFN-gamma influences the activity of macrophages, granulocytes, B-lymphocytes, suppressor-T-lymphocytes and natural killer cells as well as the production of prostaglandins and leukotrienes, bone resorption, collagen synthesis and expression of HLA class II antigens. Furthermore, the production of IFN-gamma in patients with chronic inflammatory diseases is described as well as the recent in vivo investigations concerning induction and inhibition of inflammation by IFN-gamma. Based on these investigations a hypothesis is presented which offers an explanation for the contradictory results concerning the effects of IFN-gamma in inflammation. According to this hypothesis IFN-gamma takes part in the elicitation of an inflammatory reaction. As soon as a high inflammation activity is reached the reaction is inhibited via a negative feedback. Therefore, exogenously applied IFN-gamma has a stimulating effect if inflammation activity is low. In contrary, IFN-gamma inhibits this reaction if activity is high. The consequences resulting from this dual mode of action for the treatment of different diseases with IFN-gamma are discussed.

Topics: B-Lymphocytes; Bone Resorption; Collagen; Fibroblasts; Granulocytes; HLA-D Antigens; Humans; Inflammation; Interferon-gamma; Killer Cells, Natural; Leukotriene B4; Macrophages; Prostaglandins; SRS-A; T-Lymphocytes, Regulatory

1. Sensitized guinea pig lungs release substantial amounts of prostaglandin E2, 6-keto-prostaglandin F1 alpha, thromboxane B2 and leukotrienes B4 and D4 upon challenge with the specific antigen. 2. A specific Platelet Activating Factor (PAF) antagonist (BN-52021) significantly inhibited the release of these mediators from anaphylactic lungs, suggesting the existence of interactions between PAF and eicosanoids. 3. The injection of PAF into unsensitized guinea pig lungs induced the release of prostaglandin E2, thromboxane B2 and leukotrienes B4 and D4 as well as spasmogens having contractile effects on the trachea, bronchus and parenchyma strips. 4. Our studies on the mechanism of action of PAF suggest that the actions of PAF are mediated by leukotriene B4 which in turn release thromboxane A2. Recent results suggest that similar interactions between PAF and eicosanoids are likely in immune-complex hypersensitivity reaction in the rat.

Topics: Animals; Arachidonic Acids; Dinoprostone; Diterpenes; Eicosanoic Acids; Enzyme Activation; Ginkgolides; Guinea Pigs; Hypersensitivity; Inflammation; Lactones; Leukotriene B4; Lung; Muscle Contraction; Phospholipases; Phospholipases A; Platelet Activating Factor; Prostaglandins E; SRS-A; Thromboxane B2

The arachidonic acid substitution by an alternative fatty acid, substrate for the 5-lipoxygenase and the cyclo-oxygenase pathway constitutes a novel therapeutic approach or a complement for other therapeutics in the inflammation area. Eicosapentaenoic acid (EPA), one of the fish oil components, is a substrate for both enzymes and an inhibitor for several enzymes of arachidonic acid cascade, in vitro and in vivo. The EPA-generated metabolites have less pro-inflammatory effects than those produced by arachidonic acid metabolism.

Topics: Arachidonate 5-Lipoxygenase; Arthritis, Rheumatoid; Eicosapentaenoic Acid; Fish Oils; Humans; Inflammation; Leukotriene B4; Neutrophils

The distinctive characteristics of human polymorphonuclear (PMN) leukocyte receptors for leukotriene B4 (LTB4) have been elucidated by studies of binding of [3H]LTB4, the structure of protein constituents of the receptors isolated from plasma membranes, and the effects of antireceptor antibodies. A high-affinity class of 4400 receptors with a KD of 0.4 nM mediates chemotaxis and increased adherence of PMN leukocytes, whereas a low-affinity class of 270,000 receptors with a KD of 61 nM mediates the release of lysosomal enzymes and increases in oxidative metabolism. The low-affinity receptors are composed of a 60,000-dalton protein-binding unit. The high-affinity receptors are composed of the same binding unit in association with a 40,000-dalton guanine nucleotide-binding protein. That antireceptor antibodies as well as LTB4 distinguish the two classes of receptors with different functional consequences suggests the possibility of unique approaches to the regulation of leukocyte function at the receptor level.

Topics: Antibodies, Monoclonal; GTP-Binding Proteins; Guanosine Triphosphate; Humans; Inflammation; Leukotriene B4; Models, Biological; Neutrophils; Receptors, Immunologic; Receptors, Leukotriene B4

The leukotrienes (LTs) are 5-lipoxygenase metabolites of arachidonic acid. The synthesis and release of LTs have been demonstrated in many cells and organs, and LTs are considered to be normal products of continuous metabolism of arachidonic acid. However, although evidence in favor of a critical role for LTs in regulation of physiological functions is still scarce, a growing body of evidence suggests a role for LTs in mediation of several pathophysiological processes such as generalized or local immune reactions, inflammation, asthma, shock, and trauma. LTs have been shown to have potent actions on many essential organs and systems, including the cardiovascular system (heart, blood vessels, microcirculation), the pulmonary system (lung, airways), the central nervous system (neural, glial, and vascular elements), the gastrointestinal tract, and the immune system. In these organs the effects of LTs are mediated by specific LT receptors. Identification of LTs and characterization of their regional and systemic pathological effects, together with characterization of their receptors and elucidation of their structure-activity relationships, are fundamental to developing LT antagonists or synthesis inhibitors that might prevent or reverse LT-dependent reactions. Preliminary reports have already shown that such pharmacological agents ameliorate some aspects of disease processes in experimental animals as well as in humans. In this brief review we intend to highlight the evidence that implicates LTs in normal physiological functions as well as in disease processes.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Cardiovascular Diseases; Cardiovascular Physiological Phenomena; Central Nervous System; Central Nervous System Diseases; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Respiration Disorders; Respiratory Physiological Phenomena; SRS-A; Vasomotor System; Wounds and Injuries

Topics: Animals; Humans; Inflammation; Leukotriene B4

Topics: Acute Disease; Animals; Humans; Inflammation; Leukotriene B4; SRS-A

The complement anaphylatoxin peptides, C3a and C5a, are potential mediators of immediate hypersensitivity reactions, eliciting many of the same actions on isolated tissue and cell preparations as specific antigen. Instilled intratracheally in experimental animals, the peptides induce acute bronchospasms and are sometimes lethal. In vitro, they cause dose-dependent contraction of isolated lung tissue preparations, a response which correlates well with bronchospasms observed in vivo, and our current understanding of the cellular and molecular mechanisms of this action are reviewed here. C5a and its catabolic derivative, C5ades Arg, stimulate contraction of isolated guinea pig lung parenchymal strips in part by production of leukotrienes that constitute SRS-A, and by release of histamine. Leukotrienes in turn release thromboxane from lung tissue, and evidence indicates that at least part of the spasmogenic activity of these peptidolipids is mediated by this effect. C3a is considerably less potent than C5a in contracting lung tissues and appears to act primarily by causing the release of spasmogenic cyclooxygenase metabolites. Both peptides may additionally have direct action on contractile cells within the tissue. Platelet-activating factor (PAF), an unusual phospholipid mediator released from inflammatory cells stimulated with C5a and other agents, also contracts isolated lung parenchymal tissues. PAF stimulates release of significant quantities of thromboxane from guinea pig lung; however, indomethacin does not block contractile responses of the tissue. Recent evidence indicates that PAF may act on parasympathetic neurons in lung to release endogenous acetylcholine, and this action may be a major component of tissue responses to this mediator. Thus the complement anaphylatoxins stimulate release of many of the same mediators from lung tissues as are released by antigen challenge of sensitized tissue, and may, therefore, play an important role in the pathogenesis of allergic bronchospasms.

Topics: Anaphylatoxins; Animals; Bronchi; Bronchial Spasm; Complement Activation; Complement C3; Complement C3a; Complement C5; Complement C5a; Dose-Response Relationship, Drug; Inflammation; Leukotriene B4; Lung; Mice; Muscle Contraction; Peptides; Platelet Activating Factor; SRS-A

Anaphylatoxins, in particular C3a and C5a, have various biological activities which suggest a role as mediators of inflammatory reactions: they cause contraction of smooth muscle, histamine release, increase in capillary permeability, adhesion of leukocytes to vascular endothelium, leukocyte chemotaxis, and aggregation of platelets and leukocytes. Most of these effects are supported by the cooperation of other mediators, in particular arachidonic acid derivatives which may be produced by anaphylatoxin-stimulated cells, e.g. leukocytes or endothelium. In vivo effects of the complement peptides depend very much on the site of their generation: intravascular release in the general circulation leads to adverse symptoms such as adult respiratory distress syndrome and shock lung, mainly due to leukocyte activation, aggregation and their accumulation in lung vessels. Intravascular release may be induced by certain drugs, and by contact of blood with the surfaces of bypass or dialysis apparatus. Induction of local inflammatory and defense reactions requires release of anaphylatoxins in tissue spaces. Tissue fluid differs quantitatively from blood plasma in its concentration of complement components. This raises some problems of how efficient concentrations of C3a and C5a can be attained at the site of a lesion to generate a chemotactic gradient capable of attracting blood leukocytes.

Topics: Anaphylatoxins; Antibody Formation; Blood Vessels; Chemotaxis, Leukocyte; Complement Activation; Complement C3; Complement C3a; Complement C5; Complement C5a; Humans; Immune Tolerance; Inflammation; Leukocytes; Leukotriene B4; Peptides; Shock; Tissue Distribution; Vasodilation

Topics: Animals; Arachidonate 5-Lipoxygenase; Humans; Immune System; In Vitro Techniques; Inflammation; Leukocytes; Leukotriene B4; Prostaglandins; SRS-A; Thromboxane A2

Gastrointestinal inflammation is a prominent feature of protective reactions in animals immune against helminths. Infiltration into the inflamed mucosa of various cells and their subsequent activation result in the elaboration of an array of pharmacologically and biologically active substances. The release of mediators is also associated with alterations in the epithelial layer. Furthermore, increased smooth muscle reactivity and enhanced secretory function of the mucosal tissue contribute to the development of an unfavourable environment and lead to worm expulsion. Mediators elaborated from inflammatory cells, whether associated with cell granules (i.e., preformed) or de novo-generated from membrane phospholipids, possess a number of potent vasoactive and spasmogenic properties which may contribute to events leading to worm elimination. The lipoxygenase metabolites of arachidonic acid (leukotrienes) derived from cell membranes probably contribute to the state of intestinal hypersensitivity against helminths. The measurement of elevated levels of these lipid mediators following worm challenge of immune, but not control, rats suggests that leukotrienes may play a role in amplifying and augmenting the inflammatory process associated with worm expulsion.

Topics: Animals; Eosinophils; Helminthiasis; Humans; Immunoglobulin E; Inflammation; Intestinal Diseases, Parasitic; Intestinal Mucosa; Leukotriene B4; Mast Cells; Mucus; Muscle, Smooth; Neutrophils; Rats; SRS-A

A problem of leukotrienes--metabolites of arachidonic acid is reviewed in immunological aspects. Their nomenclature is given; basic pathways of biosynthesis, transformation and mode of leukotriens participation in hypersensitivity and inflammatory reactions are considered. The possibility of application of leukotrienes antagonists and inhibitors of their formation for allergic diseases treatment is discussed.

Topics: Animals; Antigens; Arachidonic Acids; Drug Synergism; Guinea Pigs; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Neurotransmitter Agents; Rabbits; Receptors, Immunologic; SRS-A; Structure-Activity Relationship; Terminology as Topic; Thromboxane A2

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Asthma; Cell Movement; Cytoplasmic Granules; Heparin; Histamine; Humans; Inflammation; Leukotriene B4; Mast Cells; Neutrophils; Prostaglandin D2; Prostaglandins D; Rats; SRS-A

The leukotrienes (LTs) are a novel group of biologically active mediators derived from arachidonic acid via lipoxygenase enzymes. LTB4 is a potent chemotactic agent for polymorphonuclear leukocytes and in vivo may mediate inflammatory reactions by inducing leukocyte recruitment by mediating indirectly vascular permeability charges and by modulating pain responses. LTC4 and LTD4 collectively account for the biological activity known as slow-reacting substance of anaphylaxis and are potent smooth muscle contracting agents. They may mediate inflammatory reactions by producing changes in blood flow and increases in vascular permeability. Evidence for LT involvement in a number of pathological conditions including diseases such as asthma, psoriasis, ulcerative colitis, and gout is now accumulating.

Topics: Animals; Arthritis, Rheumatoid; Asthma; Colitis, Ulcerative; Gout; Humans; In Vitro Techniques; Inflammation; Leukotriene B4; Neutrophils; Psoriasis; Rabbits; SRS-A

The involvement in inflammatory conditions of those cyclo-oxygenase and lipoxygenase derivatives of arachidonic acid (5,8,11,14-eicosatetraenoic acid), which are known as the eicosanoids, is reviewed in the light of recent studies. Although it is now generally recognized that cyclo-oxygenase products are fundamental to the inflammatory process as chemical mediators, and that inhibition of the cyclo-oxygenase enzyme pathway explains the mode of action of most non-steroidal anti-inflammatory drugs (NSAIDs) commonly prescribed in veterinary practice, evidence for the involvement of lipoxygenase products of arachidonate metabolism in inflammation is increasing. The leukotrienes (LTs) are 5-lipoxygenase-derived eicosanoids which have been shown to be leucotactic and involved in anaphylactic and hypersensitivity reactions. Leucocytes, drawn to sites of injury by chemotaxis, themselves liberate pro-inflammatory eicosanoids which perpetuate the response and may aggravate the clinical condition. At therapeutic dose rates, most NSAIDs have no effect on the biosynthesis of LTs, whereas corticosteroids, by inhibiting the release of arachidonic acid, may prevent the formation of both cyclo-oxygenase and lipoxygenase products. However, because of the undesirable side-effects of steroids, the clinical use of these agents in treating inflammatory conditions is sometimes limited. Novel non-steroid inhibitors of cyclo-oxygenase and lipoxygenase enzyme pathways could offer more effective and safer control of inflammation in animals.

Topics: Animal Diseases; Animals; Anti-Inflammatory Agents; Arachidonic Acids; Cattle; Chemotaxis, Leukocyte; Guinea Pigs; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Prostanoic Acids; Rabbits; Rats

Topics: Arachidonic Acid; Arachidonic Acids; Blood Vessels; Chemical Phenomena; Chemistry; Diet; Humans; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Myocardium; Skin; SRS-A

Topics: Animals; Blood Pressure; Cardiovascular Physiological Phenomena; Cardiovascular System; Humans; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase; Lung; Organ Specificity; SRS-A; Terminology as Topic

Topics: Animals; Calcium; Chemotaxis; Cricetinae; Guinea Pigs; Homeostasis; Humans; Hypersensitivity; Immunity; In Vitro Techniques; Inflammation; Leukotriene B4; Mice; Microcirculation; Neutrophils; Phagocytes; SRS-A; T-Lymphocytes, Cytotoxic; Vasoconstriction

Topics: Animals; Arteries; Asthma; Biological Assay; Humans; Immune System Diseases; Inflammation; Leukotriene B4; Lung; Muscle, Smooth; SRS-A; Structure-Activity Relationship

Topics: Animals; Anti-Inflammatory Agents; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; Prostaglandins; SRS-A; Thromboxanes

Although prostaglandin research began about 50 years ago, many of the most important advances in understanding the biochemistry, physiology and pharmacology have taken place within the past five to ten years. There is great potential for the extension of this research to the clinical practice of medicine. At this time, the most common interaction that clinicians have with the prostaglandin field is in administering nonsteroidal anti-inflammatory drugs, which function by inhibiting prostaglandins. The uses of these drugs include treating not only inflammation, but also dysmenorrhea, some renal disease, thrombotic diseases and some metabolic disorders. Prostaglandin analogs, with their potent effects on uterine contraction, are in common use in obstetrics. Other analogs, with gastric and duodenal cytoprotective effects are useful in treating peptic ulcer disease. Future benefits from prostaglandin and leukotriene research may include new therapy for inflammatory and hypersensitivity diseases such as asthma, inflammatory bowel diseases and dermatitis.

Topics: Animals; Anti-Inflammatory Agents; Cardiovascular Diseases; Chemical Phenomena; Chemistry; Digestive System; Digestive System Physiological Phenomena; Female; Humans; Immunity, Cellular; Inflammation; Kidney; Leukotriene B4; Lung; Lung Diseases; Male; Metabolic Diseases; Pregnancy; Prostaglandin Antagonists; Prostaglandins; Reproduction; SRS-A; Thromboxanes; Uterine Contraction

Topics: Animals; Factor XII; Free Radicals; Granulocytes; Histamine; Humans; Inflammation; Kinins; Leukotriene B4; Lymphocytes; Lymphokines; Lysosomes; Macrophages; Mice; Nucleotides, Cyclic; Plasminogen; Prostaglandins; Rats; Serotonin; SRS-A; Superoxides

Certain polyunsaturated fatty acids, such as arachidonic acid, are metabolized by oxygenation into a large family of biologically active substances, the prostanoids. These include the prostaglandins, thromboxanes, prostacyclins, leukotrienes and also a number of related compounds. Oxygenation can take place at many different positions of arachidonic acid. A cyclo-oxygenase introduces oxygen at C-11 and converts the resulting peroxy compound into a 9, 11-endoperoxide structure. The cyclic peroxides thus formed, PGG2 and PGH2, are highly potent compounds and are the immediate precursors of the prostaglandins, thromboxanes and prostacyclin. Other enzymes, the lipoxygenases, may instead introduce oxygen at C-5, C-8, C-9, C-12 or C-15: further conversions from, for example, the initially formed 5- or 15-hydroperoxy acids may lead to the leukotrienes. The prostanoids display strong and varied biological activities, and have effects on numerous processes in the body. In some pathological conditions the prostanoids play important roles. For example, certain products of the arachidonic acid cascade are considered to be mediators of the inflammatory response: they are formed during the process, contribute to the symptoms of erythema, vascular leakage, fever, pain and chemotaxis, and inhibition of their biosynthesis can be achieved at different levels by the anti-inflammatory drugs.

Topics: Animals; Anti-Inflammatory Agents; Arachidonic Acid; Arachidonic Acids; Epoprostenol; Humans; Inflammation; Leukotriene B4; Prostaglandins; SRS-A; Thromboxanes

Topics: Animals; Anti-Inflammatory Agents; Antibody Formation; Azathioprine; Cyclophosphamide; Cyclosporins; Humans; Hybrid Cells; Immunity, Cellular; Immunoglobulins; Inflammation; Killer Cells, Natural; Leukotriene B4; Levamisole; Mast Cells; Models, Biological; Prostaglandins; SRS-A; T-Lymphocytes

Various substances considered as mediators responsible for regulation of both cellular and humoral components of inflammatory and allergic reactions are produced in course of oxidation of arachidonic acid by means of lipoxygenase. These substances included a number of stereochemically different monohydroxyeicosatetraenoic acids as well as leukotrienes. Components of slowly acting substance in anaphylaxis (leukotrienes C4 and D4) caused contraction of smooth muscles, constriction of bronchopulmonary system, alteration in permeability and tonus of capillary blood vessels in skin and other tissues. Leukotriene B and 5-monohydroxyeicosatetraenoic acid caused mobilization of neutrophils in the reaction of hypersensitivity of the delayed type. Contrary to prostaglandins, formed from arachidonic acid by cyclooxygenase, monohydroxyeicosatetraenoic acids and leukotrienes are considered as pathological agents only. Distinct and long-term effect of these substances on tissues suggest that the lipid mediators of inflammation will be important in studies of pathogenesis of various acute and chronic diseases.

Topics: Animals; Arachidonic Acids; Calcium; Carboxy-Lyases; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Leukotrienes; Methyltransferases; Muscle, Smooth; Oxidation-Reduction; Phospholipases; SRS-A

Topics: Anti-Inflammatory Agents; Arachidonic Acid; Arachidonic Acids; Arthritis; Chemical Phenomena; Chemistry; Chemotactic Factors; Humans; Inflammation; Intestinal Diseases; Leukotriene B4; Lipoxygenase; Lung Diseases; Lymphocytes; Mast Cells; Neutrophils; Receptors, Cell Surface; Skin Diseases; SRS-A

Topics: Animals; Anti-Inflammatory Agents; Arachidonic Acids; Capillary Permeability; Edema; Eicosanoic Acids; Erythema; Fever; Humans; Hyperalgesia; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Muscle, Smooth, Vascular; Pain; Prostaglandin Antagonists; Prostaglandins; SRS-A

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Capillary Permeability; Edema; Fever; Humans; Inflammation; Leukotriene B4; Lipoxygenase; Lymphocytes; Pain; Phagocytes; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Regional Blood Flow

Prostaglandins, thromboxanes and leukotrienes are oxygen metabolites of arachidonic acid forming a family of lipidic substances with intrinsic biological activities. The significance of biosynthesis of these mediators in response to cell stimulation remains unclear. Numerous data suggest that these compounds, produced by blood cells and vascular cells, play an important role in cardiovascular pathology, allergy or inflammation. The concept, based on biochemistry, of distinct metabolic pathways should be reappraised, using a physiological approach that involves a biological effect resulting from a synergistic action of different compounds. The development of specific assay methods will permit to investigate compounds obtained from biological fluids or from cells present in recognized pathological situations. Such in vitro data should help to clarify the role of these autacoids in cardiovascular, allergic or inflammatory diseases.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Cardiovascular Diseases; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Lipoxygenase; Prostaglandin-Endoperoxide Synthases; Prostaglandins; SRS-A; Thromboxanes

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Basophils; Capillary Permeability; Cell Adhesion; Cell Aggregation; Chemotaxis, Leukocyte; Eosinophils; Guinea Pigs; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Lymphocytes; Macrophages; Muscle, Smooth; Neutrophils; Rabbits; Rats; SRS-A; Superoxides

Leukotrienes are released in inflammatory and immediate hypersensitivity reactions. Leukotrienes are novel metabolites of arachidonic acid produced by the lungs and leucocytes. Their formation is catalyzed by a specific 5-lipoxygenase. The key compound of this pathway is leukotriene A4 which is transformed either into leukotriene B4 by enzymatic hydrolysis or into leukotriene C4 by addition of glutathione. Leukotriene D4 and E4, as well as their precursor leukotriene C4, are the myotropic constituents of the "Slow Reacting Substance of Anaphylaxis" (SRS-A). Leukotrienes are potent bronchoconstrictors in vitro and in vivo. They induce the production of mucus by the respiratory tract and decrease its transport. Leukotrienes (chiefly leukotrienes C4, D4 and E4) induce the vasoconstriction of large vessels and capillaries. Leukotriene B4 stimulates several leukocyte functions related to inflammation (chemotaxis, aggregation, release of lysosomal enzymes and production of superoxide anion). In addition, it induces the formation of suppressive and cytotoxic T-Lymphocytes. The actions of leukotrienes are mediated by specific receptors and, in certain organs, their mechanism of action involves a stimulation of the formation of prostaglandins and thromboxanes. Non-steroidal antiinflammatory drugs (aspirin) inhibit the biosynthesis of prostaglandins and thromboxanes, whereas steroidal antiinflammatory agents (dexamethasone) should inhibit the production of leukotrienes as well as of prostaglandins and thromboxanes (through an indirect action on phospholipase A2).

Topics: Animals; Arachidonic Acids; Asthma; Blood Vessels; Cromolyn Sodium; Heart; Humans; Inflammation; Leukocytes; Leukotriene B4; Respiratory Physiological Phenomena; Respiratory System; SRS-A

Leukotrienes are a new family of metabolites of arachidonic acid produced by a C-5 lipoxygenase. As shown on figure 1, leukotriene A4, the key compound in their biosynthesis could either be hydrolysed to form leukotriene B4 or combine with glutathione to form leukotriene C4. Removal of glycine from the glutathione substituent or removal of glycine and gamma-glutamic acid yields the leukotriene D4 and E4 respectively. Leukotriene C4, D4 and E4 are the main bioactive components of the long elusive "Slow Reacting Substance of Anaphylaxis" (SRS-A). They induce powerful contractions of lung parenchyma strips and trachea in vitro (fig. 2) as well as powerful bronchoconstriction in vivo. They also favor mucus production from airways and slow its transport. Leukotrienes exhibit vasoconstrictor activity both on large blood vessels and on the microcirculation and induce marked increases in blood pressure followed by long lasting slight decreases (fig. 3). Injections of leukotriene B4 produce erythema, neutrophil migration and, in association with prostaglandin E2, increase vascular permeability and cause oedema. Leukotriene B4 is a powerful chemoattractant for polymorphonuclear leukocytes, stimulates cellular aggregation, degranulation and the release of lysosomal enzymes. It is also involved in the modulation of the immune response by inducing the formation of suppressor and of cytotoxic cells. The pharmacological actions of leukotriene B4 are mediated by very specific receptors while the actions of leukotriene C4, D4 and E4 are mediated by another type of receptors which are blocked by the selective SRS-A antagonist FPL-55712. The actions of leukotrienes depend partly upon the formation of prostaglandins and thromboxanes in the guinea-pig lungs while in man, their actions appear mostly a direct myotropic effect (fig. 4). Leukotriene formation has been stimulated in lungs and in various leukocyte populations by inflammatory or hypersensitivity reactions and by non specific stimuli such as the ionophore A-23187 and the C5a-anaphylatoxin. Inhibitors of lipoxygenases and corticosteroids could inhibit their release while non-steroid anti-inflammatory drugs such as aspirin may potentiate their formation by rechanneling their substrate from the cyclooxygenase cascade (fig. 5). The activity and potency of leukotrienes, their putative role in various important diseases as well as the explanations which they may give to old problems are good reasons to justify our interest

Topics: Animals; Arachidonic Acids; Cardiovascular System; Humans; Inflammation; Leukocytes; Leukotriene A4; Leukotriene B4; Lung; SRS-A

Topics: Anti-Inflammatory Agents; Arachidonic Acid; Arachidonic Acids; Biotransformation; Cyclooxygenase Inhibitors; Gastric Mucosa; Hemostasis; Humans; Inflammation; Leukotriene A4; Leukotriene B4; Muscle, Smooth; Neutrophils; Prostaglandins; SRS-A; Thromboxanes

Neutrophils secrete of variety of biologically active compounds, especially when they accumulate at sites of inflammation. Secretory products are delivered to the tissues both by exocytosis of cytoplasmic granules and by metabolic events taking place at the plasma membrane. The release of lysosomal constituents, such as lactoferrin, elastase and collagenases, is associated with the regulation of the turnover of neutrophils, their participation and activity in the inflammatory reaction, and breakdown of cartilage and connective tissues, for example. Generation of cytotoxic oxygen radicals and compounds, e.g. the superoxide anion, hydrogen peroxide and the hydroxyl radical, is initiated by many inflammatory mediators. These two systems, either individually or in collaboration, can cause damage to many types of structures. For instance, when endothelial cells are injured, increased vascular permeability may occur. If such injury involves the pulmonary capillary system a respiratory distress syndrome may supervene. Leukotrienes are potent mediators of inflammation, formed in neutrophils after exposure to various other chemotactic or perturbating compounds. Leukotriene B4 is the most potent of the hitherto described compounds, being a promotor of neutrophil adherence, aggregation and chemotaxis in vitro of similar potency as the formylated synthetic chemotactic peptides, e.g. fMLP, and as the C5a fragment. However, the ability of LTB4 to induce a release of lysosomal enzymes is only half of that of fMLP, and, finally, the capacity to initiate a chemiluminescence response, being a measure of the oxidative metabolism, is only one-tenth of that of fMLP. Thus, leukotrienes of the B series seem to be a signal system whereby activated neutrophils can recruit cellular reinforcements, and, possibly, to act as an intracellular, second messenger system.

Topics: Cell Aggregation; Chemotaxis, Leukocyte; Granulocytes; Humans; Hydrogen Peroxide; Inflammation; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Peroxidase; Superoxides

Topics: Anti-Inflammatory Agents; Arachidonic Acids; Chemical Phenomena; Chemistry; Dinoprostone; Epoprostenol; Humans; Inflammation; Leukotriene B4; Lipoxygenase; Oxidation-Reduction; Prostaglandin-Endoperoxide Synthases; Prostaglandins E; SRS-A

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Bone and Bones; Cartilage; Cyclic AMP; Humans; Inflammation; Leukotriene B4; Lymphocytes; Lysosomes; Prostaglandins; Prostaglandins E; SRS-A

Topics: Allergy and Immunology; Animals; Anti-Inflammatory Agents; Arachidonic Acid; Arachidonic Acids; History, 20th Century; Immunity, Cellular; Inflammation; Leukotriene B4; Lipoxygenase; Neutrophils; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Rats; United States

Topics: Anaphylaxis; Animals; Arachidonic Acid; Arachidonic Acids; Autacoids; Chemical Phenomena; Chemistry; Chemotactic Factors; Chemotactic Factors, Eosinophil; Histamine; Humans; Hydrolases; Inflammation; Leukocytes; Leukotriene B4; Mast Cells; Platelet Activating Factor; Prostaglandins; Serotonin; SRS-A; Structure-Activity Relationship; Thromboxanes; Vasoactive Intestinal Peptide

Topics: Animals; Arachidonic Acids; Chemical Phenomena; Chemistry, Physical; Cytoplasmic Granules; Histamine Release; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Mast Cells; Membrane Lipids; Methylation; Phospholipids; Rats; Receptors, Fc; Receptors, IgE; Receptors, Immunologic; SRS-A

Topics: Animals; Anti-Inflammatory Agents; Arachidonic Acids; Chemotaxis, Leukocyte; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Prostaglandins

Topics: Animals; Antibody Formation; Arachidonic Acids; Cell Membrane; Dinoprostone; Guinea Pigs; Immune Tolerance; Inflammation; Leukotriene B4; Macrophage Activation; Macrophages; Monocytes; Phagocytosis; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Prostaglandins E; SRS-A

Leukotriene B4 (LTB4) is a 5, 12-dihydroxy derivative of arachidonic acid generated by a variety of inflammatory cells via the lipoxygenase enzyme system. In vitro leukotriene B4 is a potent chemotactic and aggregatory agent; enhances neutrophil complement receptors; stimulates membrane calcium changes and causes contraction of lung parenchyma. In vivo LTB4 is a potent stimulator of vascular permeability in rats, rabbits, guinea-pigs and man particularly in the presence of a vasodilator such as PGE2. LTB4 causes a profound transient neutropenia and massive accumulation of neutrophils when injected into the dermis (rabbit and man), skin chambers (rabbit and man) or body cavities (guinea-pig, rat).

Topics: Animals; Arachidonic Acids; Blood Platelets; Capillary Permeability; Chemotaxis; Humans; In Vitro Techniques; Inflammation; Leukotriene B4; Neutrophils

Immunological and non-immunological injury induce as a result of the action of the enzyme lipoxygenase the release of a series of arachidonic acid metabolites known as leukotrienes. The leukotrienes play an important role in allergic and inflammatory disease. Leukotrienes C4, D4 and E4 which recently have been recognized as constituents of the allergic mediator slow reacting substance of anaphylaxis (SRS-A) induce powerful bronchoconstriction, plasma exudation and weal and flare responses. Leukotriene B4 is involved in the regulation of chemotaxis, chemokinesis and other aspects of both cellular and vascular inflammation. The development of specific lipoxygenase inhibitors may lead to a new class of drugs for the treatment of bronchial asthma and chronic inflammatory diseases.

Topics: Arachidonic Acids; Asthma; Biotransformation; Chemotaxis, Leukocyte; Humans; Hypersensitivity; Inflammation; Leukotriene A4; Leukotriene B4; Leukotriene E4; Lipoxygenase; Lipoxygenase Inhibitors; Neutrophils; SRS-A

Topics: Animals; Arachidonic Acids; Autacoids; Guinea Pigs; Humans; Hypersensitivity; Inflammation; Leukotriene A4; Leukotriene B4; Molecular Conformation; Neutrophils; Rats; SRS-A; Structure-Activity Relationship; Terminology as Topic

The aim of this study was to document anti-inflammatory properties of a dried fermentate derived from Saccharomyces cerevisiae (EpiCor(®)), hereafter referred to as dried fermentate in vitro using cell-based bioassays, and in vivo using a skin irritation model in healthy humans. In vitro testing involved parallel assessment of primary human polymorphonuclear (PMN) cell formation of reactive oxygen species (ROS) and migration toward the inflammatory mediator Leukotriene B4. In vivo evaluation used a single-blind placebo-controlled design, where dermal histamine-induced inflammation was used as a model for the complex intercellular signals involved in the initiation, escalation, and resolution of the inflammatory response. Microvascular blood perfusion was evaluated using noninvasive laser Doppler probes applied to the inner forearms of 12 healthy human subjects, where parallel sites were treated with either dried fermentate or saline (placebo). Subjective scores of dermal irritation were also collected. Treatment of PMN cells in vitro resulted in reduced ROS formation and migratory activity toward Leukotriene B4. Clinical results demonstrated significantly reduced microvascular inflammatory responses to histamine-induced skin inflammation, and significantly reduced subjective scores of irritation at the inflamed sites treated with dried fermentate compared with the sites treated with placebo (P<.05). Treatment of inflammatory cells in vitro with dried fermentate resulted in reduced inflammatory responses. This was confirmed in vivo, suggesting that the dried fermentate facilitates the resolution of inflammatory responses. The effects using a topical skin model suggest that similar events may happen when the dried fermentate is introduced across mucosal membranes after consumption.

Topics: Adult; Anti-Inflammatory Agents; Biological Products; Female; Fermentation; Histamine; Humans; In Vitro Techniques; Inflammation; Leukotriene B4; Male; Middle Aged; Reactive Oxygen Species; Saccharomyces cerevisiae; Single-Blind Method; Skin; Young Adult

We previously reported that a 4- to 6-week low-fat fish oil (LFFO) diet did not affect serum insulin-like growth factor (IGF)-1 levels (primary outcome) but resulted in lower omega-6 to omega-3 fatty acid ratios in prostate tissue and lower prostate cancer proliferation (Ki67) as compared with a Western diet. In this post hoc analysis, the effect of the LFFO intervention on serum pro-inflammatory eicosanoids, leukotriene B4 (LTB4) and 15-S-hydroxyeicosatetraenoic acid [15(S)-HETE], and the cell-cycle progression (CCP) score were investigated. Serum fatty acids and eicosanoids were measured by gas chromatography and ELISA. CCP score was determined by quantitative real-time reverse transcriptase PCR (RT-PCR). Associations between serum eicosanoids, Ki67, and CCP score were evaluated using partial correlation analyses. BLT1 (LTB4 receptor) expression was determined in prostate cancer cell lines and prostatectomy specimens. Serum omega-6 fatty acids and 15(S)-HETE levels were significantly reduced, and serum omega-3 levels were increased in the LFFO group relative to the Western diet group, whereas there was no change in LTB4 levels. The CCP score was significantly lower in the LFFO compared with the Western diet group. The 15(S)-HETE change correlated with tissue Ki67 (R = 0.48; P < 0.01) but not with CCP score. The LTB4 change correlated with the CCP score (r = 0.4; P = 0.02) but not with Ki67. The LTB4 receptor BLT1 was detected in prostate cancer cell lines and human prostate cancer specimens. In conclusion, an LFFO diet resulted in decreased 15(S)-HETE levels and lower CCP score relative to a Western diet. Further studies are warranted to determine whether the LFFO diet antiproliferative effects are mediated through the LTB4/BLT1 and 15(S)-HETE pathways.

Topics: Aged; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Diet, Fat-Restricted; Disease Progression; Eicosanoids; Fatty Acids; Fish Oils; Gene Expression Regulation, Neoplastic; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Insulin-Like Growth Factor I; Ki-67 Antigen; Leukotriene B4; Male; Middle Aged; Prostatectomy; Prostatic Neoplasms; Receptors, Leukotriene B4

Research has revealed new insights into the pathogenesis of psoriasis, leading to new therapeutic options. So far the order of changes in the pathogenesis of psoriasis is unclear. The responses to cutaneous leukotriene B4 (LTB4) application have been studied in the past as an in vivo model for inflammation. The aim of the present study is to find out the order of changes of key steps in inflammation, which all have been shown to be involved in mature psoriatic lesions.. To study the dynamics of the consecutive stages of inflammation in challenged skin as a reflection of a psoriasis-like inflammatory response.. We examined the dynamics of epidermal growth control and the key representatives of the innate and acquired immune system during the first 72 h after challenging the skin by LTB4 application.. Interleukin 17-positive (IL-17+) cells dominate the acute phase of inflammation, whereas T-Bet+ cells seem to increase gradually during the entire observation period. This indicates a more important role for IL-17 in the unstable phase of inflammation and a more prominent role for T-Bet+ cells within the chronic phase.. The present model is highly reproducible and is useful in studying the dynamics of a psoriasis-like inflammation with respect to key components of immunity. It could provide a useful tool to study the immediate biological effects of new therapies like anti-IL-17 drugs on IL-17 production and effects on cutaneous inflammation and epidermal proliferation in vivo.

Topics: Adult; Female; Humans; Inflammation; Interleukin-17; Leukotriene B4; Male; Middle Aged; Models, Biological; Psoriasis; Reproducibility of Results; Skin; Th1 Cells; Th17 Cells; Young Adult

Compared with soybean oil, a fish oil-enriched emulsion can improve the clinical outcomes of patients requiring parenteral nutrition. However, the superiority of fish oil emulsion to medium-chain triacylglycerols/long-chain triacylglycerols for short-term administration has seldom been discussed.. Sixty-four adult patients with gastrointestinal diseases were randomly assigned to receive isocaloric and isonitrogenous total parenteral nutrition with an ω-3 fatty acid-enriched emulsion (Lipoplus; study group, n = 32) or medium-chain triacylglycerols/long-chain triacylglycerols (Lipofundin; control group, n = 32) for 5 d after surgery. Safety and efficacy parameters were assessed on postoperative days 1, 3, and 6.. Clinical outcomes including infectious complications and systemic inflammatory response syndrome were comparable between the two groups. Total bilirubin decreased over time in the study group versus an increase in the control group (P = 0.017). Activated partial thromboplastin time in the study group was prolonged significantly compared with the control group from days 1 to 3 (P = 0.002), although the prolongation stopped at the study termination. There were no differences in changes of C-reactive protein, interleukin (IL)-1, IL-8, IL-10, vascular endothelial growth factor (VEGF), and the distribution of the T-cell subpopulation between the two groups. However, fish oil consumption led to an increase in leukotriene B5/ leukotriene B4 and significant decreases in IL-6, tumor necrosis factor-α, and nuclear factor-κB. Furthermore, the overall changes in tumor necrosis factor-α and nuclear factor-κB were positively associated (R(2) = 0.295, P < 0.001).. Gastrointestinal surgery patients benefited from a fish oil-enriched emulsion rather than medium-chain triacylglycerols/long-chain triacylglycerols in the amelioration of liver function and immune status. The positive association of tumor necrosis factor-α and nuclear factor-κB might be involved in the potential anti-inflammation mechanism of fish oil.

Topics: Adult; Aged; Anti-Inflammatory Agents; Bilirubin; Cross Infection; Dietary Fats; Eicosapentaenoic Acid; Fat Emulsions, Intravenous; Fatty Acids, Omega-3; Female; Fish Oils; Gastrointestinal Diseases; Humans; Immunity; Inflammation; Inflammation Mediators; Leukotriene B4; Liver; Male; Middle Aged; NF-kappa B; Parenteral Nutrition; Partial Thromboplastin Time; Postoperative Complications; Systemic Inflammatory Response Syndrome; Triglycerides; Tumor Necrosis Factor-alpha

Acute respiratory failure in neonates (e.g. ARDS, meconium aspiration pneumonitis, pneumonia) is characterized by an excessive inflammatory response, governing the migration of polymorpho-nuclear leukocytes (PMNLs) into lung tissue and causing consecutive impairment of gas exchange and lung function. Critical to this inflammatory response is the activation of nuclear factor-kappaB (NF-kappaB) that is required for transcription of the genes for many pro-inflammatory mediators. We asked whether the inhibition of NF-kappaB activity using either a selective inhibitor (IKK-NBD peptide) or dexamethasone would be more effective in decreasing NF-kappaB activity and chemokine expression in pulmonary cells. Changes in lung function were repeatedly assessed for 24h following induction of acute respiratory failure and therapeutic intervention. We conducted a randomized, controlled, prospective animal study with mechanically ventilated newborn piglets which underwent repeated airway lavage (20+/-2 [SEM]) to remove surfactant and to induce lung inflammation. Admixed to 100 mg kg(-1) surfactant, piglets then received either IKK-NBD peptide (S+IKK), a selective inhibitor of NF-kappaB activation, its control peptide without intrinsic activity, dexamethasone (S+Dexa), its solvent aqua, or an air bolus only (all groups n=8). After 24h of mechanical ventilation, the following differences were measured: PaO(2)/FiO(2) (S+IKK 230+/-9 mm Hg vs. S+Dexa 188+/-14, p<0.05); ventilation efficiency index (0.18+/-0.01 [3800/(PIP-PEEP)(*)f(*)PaCO(2)] vs. 0.14+/-0.01, p<0.05); extravascular lung water (24+/-1 ml kg(-1) vs. 29+/-2, p<0.05); PMNL in BAL fluid (112+/-21 cells microl(-1) vs. 208+/-34, p<0.05), IL-8 (351+/-117 pg ml(-1) vs. 491+/-144, p=ns) and leukotriene B(4) (23+/-7 pg ml(-1) vs. 71+/-11, p<0.01) in BAL fluid. NF-kappaB activity in the nucleus of pulmonary cells differed by 32+/-5% vs. 55+/-3, p<0.001. Differences between these two intervention groups were more pronounced in the second half of the observation period (hours 12-24). At 24h of mechanical ventilation, inhibition of NF-kappaB activity by IKK-NBD peptide admixed to surfactant as a carrier caused improved gas exchange, lung function and reduced pulmonary inflammation, as evidenced by reduction in PMNL migration into lung tissue due to reduced nuclear NF-kappaB activity. We conclude that IKK-NBD admixture to surfactant in acute neonatal respiratory failure is superior to dexamethasone administration within the fir

Topics: Acute Disease; Animals; Animals, Newborn; Anti-Inflammatory Agents; Blood Cell Count; Bronchoalveolar Lavage Fluid; Dexamethasone; Inflammation; Interleukin-8; Leukotriene B4; Lung Diseases; Neutrophils; NF-kappa B; Organ Size; Pulmonary Gas Exchange; Pulmonary Surfactants; Respiration, Artificial; Respiratory Tract Diseases; Swine

High postprandial serum lipid concentrations are associated with increased oxidative stress which, in turn, increases the risk of atherosclerosis. Epidemiological studies correlate lower incidence of cardiovascular disease with adherence to the Mediterranean diet. The aim of this study was to evaluate changes in inflammatory (TXB(2) and LTB(4)) and oxidative stress markers (urinary hydrogen peroxide levels and serum antioxidant capacity), in addition to classic lipid parameters, after a fat-rich meal administered to 12 normolipemic, healthy subjects. Following a Latin square design, subjects were divided into three groups, each one receiving a different kind of oil (extra virgin olive oil; EVOO, olive oil; OO or corn oil; CO, together with 150g of potatoes), with 2-week washout periods between treatments. Blood samples were drawn at baseline and after 1, 2, and 6h after the meal. A significant decrease in inflammatory markers, namely TXB(2) and LTB(4), after 2 and 6h after EVOO (but not OO or CO) consumption and a concomitant increase of serum antioxidant capacity were recorded. These data reinforce the notion that the Mediterranean diet reduces the incidence of coronary heart disease partially due to the protective role of its phenolic components, including those of extra virgin olive oil.

Topics: Adult; Antioxidants; Blood Glucose; Cardiotonic Agents; Cholesterol, HDL; Cholesterol, LDL; Corn Oil; Coronary Disease; Diet, Mediterranean; Dietary Fats, Unsaturated; Flavonoids; Humans; Hyperlipidemias; Inflammation; Leukotriene B4; Male; Olive Oil; Oxidative Stress; Phenols; Plant Oils; Polyphenols; Postprandial Period; Thromboxane B2; Triglycerides

The aim of the present study was to examine the immune-modulating effect of two different fat blends enriched with a low dose of anti- or proinflammatory polyunsaturated fatty acids on the fatty acid status and subsequently on the immune response of healthy volunteers.. Thirty healthy volunteers were randomly assigned to group A (anti-inflammatory blend rich in polyunsaturated fatty acids: alpha-linolenic acid, 240 mg/d; eicosapentaenoic acid, 120 mg/d; stearidonic acid, 49 mg/d; and gamma-linolenic acid, 73 mg/d) or group B (arachidonic acid, 40 mg/d; containing an inflammatory fat blend) for a 2-wk dietary supplementation period. Concentrations of interleukin-8, interleukin-10, tumor necrosis factor-alpha, prostaglandins E(1) and E(2), and leukotriene B(4) were investigated before, after 2 wk of supplementation, and 2 wk after stopping supplementation using a whole blood ex vivo lipopolysaccharide-stimulation assay.. Plasma concentrations of alpha-linolenic acid and eicosapentaenoic acid were significantly increased in group A. In addition, dietary fat blends influenced eicosapentaenoic acid concentration in erythrocyte membranes. Supplementation of the fat blends resulted in contrasting effects on the expression of lipid mediators and cytokines after ex vivo lipopolysaccharide stimulation. Release of prostaglandin E(1) and leukotriene B(4) were significantly decreased in group A, whereas prostaglandin E(2) and interleukin-10 concentrations were significantly increased in group B. No effect on interleukin-8 or tumor necrosis factor-alpha release was found after supplementation with either fat blend.. These results show an immune-modulating effect of a low-dose dietary polyunsaturated fatty acid supplementation. However, further studies regarding fat-blend composition and period of supplementation in patients with inflammatory conditions are required.

Topics: alpha-Linolenic Acid; Alprostadil; Dietary Supplements; Dinoprostone; Double-Blind Method; Eicosanoic Acids; Erythrocyte Membrane; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Female; Humans; Inflammation; Interleukin-10; Interleukin-8; Leukotriene B4; Male; Time Factors; Tumor Necrosis Factor-alpha

To investigate the changes of leukotriene B(4) (LTB(4)) in induced sputum and plasma of patients with chronic obstructive pulmonary disease (COPD) and the effects of theophylline.. The investigation was a prospective, randomized controlled trial. Forty stable COPD patients (group C) were randomized into a subgroup receiving oral theophylline 0.2 g twice a day for one month (group CA) and a subgroup receiving no theophylline (group CB). Fifteen age-matched healthy non-smokers (group H) were included as controls. The following measurements were performed at baseline for each group and one month later for group C: symptom and life quality scores, pulmonary function, cell counts and cell differentials in induced sputum, and concentrations of interleukin-8 (IL-8) and LTB(4) in both induced sputum and plasma by using enzyme linked immunosorbent assay (ELISA) and enzyme immunoassay (EIA).. Concentrations of LTB(4) in induced sputum [(794 +/- 305) pg/mg x pro] and plasma [(5,219 +/- 1,185) ng/L] in group C were significantly higher than those in group H [(347 +/- 169) pg/mg x pro, (2,283 +/- 489) ng/L, all P < 0.05]. The level of LTB(4) in induced sputum was positively correlated with the percentage of neutrophil (r = 0.453, P = 0.018) and IL-8 (r = 0.364, P = 0.047). The pre-and post-therapy concentrations of LTB(4) in induced sputum and plasma in group CA were (812 +/- 592), (657 +/- 459) pg/mg x pro and (5,422 +/- 935), (4,589 +/- 1,057) ng/L, respectively; while in group CB the concentrations were (776 +/- 227), (860 +/- 194) pg/mg x pro and (5,074 +/- 1,850), (6,063 +/- 2,450) ng/L, respectively. There were no significant changes either in the level of LTB(4) in induced sputum or in plasma in both groups (all P > 0.05).. The results suggest that LTB(4) is involved in airway inflammation in COPD. Theophylline is not effective in decreasing the levels of LTB(4) in both induced sputum and plasma of COPD patients.

Topics: Aged; Bronchodilator Agents; Case-Control Studies; Female; Humans; Inflammation; Leukotriene B4; Male; Middle Aged; Plasma; Prospective Studies; Pulmonary Disease, Chronic Obstructive; Sputum; Theophylline

To evaluate the effect of therapeutic ultrasound on the acute inflammation of soft-tissue injuries by measuring the levels of prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)).. Randomized, case-control study.. Laboratory animal facility.. Thirty 3-month-old male Sprague-Dawley rats.. Rats with medial collateral ligament transection were given 5 minutes of pulsed ultrasound therapy (1:4) daily, with different durations (1, 5, 10d) and intensities (0, 0.5, 1.5, 2.3W/cm(2)).. Levels of PGE(2) and LTB(4).. The levels of PGE(2) and LTB(4) were higher in all intensity subgroups that received 2.3W/cm(2) intensity on postinjury day 2. On postinjury day 11, LTB(4) was significantly decreased, but PGE(2) was significantly increased.. Pulsed ultrasound therapy may stimulate inflammation of acute ligament injury.

Topics: Analysis of Variance; Animals; Dinoprostone; Inflammation; Leukotriene B4; Male; Medial Collateral Ligament, Knee; Rats; Rats, Sprague-Dawley; Ultrasonic Therapy

To examine the effect of n-3 polyunsaturated fatty acid supplements on the monocyte surface expression of adhesion molecules involved in proatherogenic monocyte-endothelial interactions, and on pro-inflammatory mediators in Type 2 diabetes mellitus.. Twenty-nine subjects with Type 2 diabetes and 21 controls without diabetes were studied. Monocyte expression of leucocyte function-associated antigens 1 and 3, intercellular adhesion molecule-1, and the major histocompatibility complex class II molecule HLA-DR were measured using a laser flow cytometric method. Supplementation with 2.08 g n-3 fatty acids for 21 days was undertaken and measurements repeated. Plasma soluble adhesion molecule concentrations, plasminogen activator inhibitor-1 activity and antigen and pro-inflammatory mediators (cysteinyl leukotriene and monocyte leukotriene B4) were also measured.. Groups did not differ in monocyte expression of adhesion molecules or HLA-DR, or in leukotriene production although plasma soluble adhesion molecule concentrations were higher in the diabetes groups (P<0.05). n-3 fatty acid supplementation influenced neither the expression of these molecules nor plasma soluble adhesion molecule concentrations or leukotriene production.. This study does not support increased monocyte adhesion molecule expression or abnormal monocyte production of pro-inflammatory mediators as mechanisms for increased atherogenic risk in Type 2 diabetes. Cardioprotective actions of n-3 fatty acids may not be mediated through these mechanisms.

Topics: Blood Platelets; CD58 Antigens; Diabetes Mellitus, Type 2; Dietary Supplements; England; Fatty Acids, Nonesterified; Fatty Acids, Omega-3; HLA-DR Antigens; Humans; Inflammation; Intercellular Adhesion Molecule-1; Leukotriene B4; Lymphocyte Function-Associated Antigen-1; Male; Middle Aged; Monocytes; Plasminogen Activator Inhibitor 1; Reference Values; White People

Ventilated preterm infants prone to the development of bronchopulmonary dysplasia have been shown to have increased inflammatory mediators in their tracheal aspirates. High frequency oscillatory ventilation (HFOV) is thought to be less traumatic than intermittent positive pressure ventilation (IPPV) in premature infants with surfactant deficiency, and therefore may reduce the inflammatory response in tracheobronchial aspirates. We randomized 76 premature infants requiring mechanical ventilation (birth weight 420-1830 g, median 840 g, gestational age 23 3/7 to 29 2/7 wk, median 26 4/7 to receive either an IPPV with a high rate (60-80/min) and low peak pressures, or an HFOV aiming at an optimization of lung volume, within 1 h of intubation. Tracheal aspirates were systematically collected during the first 10 d of life and analyzed for albumin, IL-8, leukotriene B4 (LTB4), and the secretory component (SC) for IgA as a reference protein. Bacterially colonized samples were excluded. On the treatment d 1, 3, 5, 7, and 10, the resulting median values of albumin (milligrams/mg of SC) were 28, 23, 24, 18, and 10, in IPPV-ventilated infants, and 33, 28, 18, 25, and 39 in HFOV-ventilated infants, respectively. Median IL-8 values (nanograms/mg of SC) were 671, 736, 705, 1362, and 1879 (IPPV) and 874, 1713, 1029, 1426, and 1823 (HFOV), respectively, and median LTB4 values (nanograms/mg of SC) were 26, 13, 27, 22, and 11 (IPPV) and 15, 12, 7, 12, and 16 (HFOV), respectively. Values were similar in IPPV- and HFOV-ventilated infants, and no significant differences were noted. We conclude that HFOV, when compared with a high rate low pressure IPPV, does not reduce concentrations of albumin, IL-8, and LTB4 in tracheal aspirates of preterm infants requiring mechanical ventilation.

Topics: Albumins; Bronchopulmonary Dysplasia; Female; High-Frequency Ventilation; Humans; Immunoglobulin A; Infant, Newborn; Infant, Premature; Inflammation; Interleukin-8; Intermittent Positive-Pressure Ventilation; Leukotriene B4; Lung; Male; Pregnancy

Although corticosteroid therapy might be clinically beneficial for bronchiectasis, very little is known of its effects on the inflammatory and infective markers in bronchiectasis. We have therefore performed a double-blind, placebo-controlled study to evaluate the effects of a 4-wk administration of inhaled fluticasone in bronchiectasis. Twenty-four patients (12 female; mean age 51 yr) were randomized into receiving either inhaled fluticasone (500 microgram twice daily) via the Accuhaler device (n = 12) or placebo. At each visit, spirometry, 24-h sputum volume, sputum leukocyte density, bacterial densities, and concentrations of interleukin (IL)-1beta, IL-8, tumor necrosis factor-alpha (TNF-alpha), and leukotriene B4 (LTB4) were determined. There was a significant (p < 0.05) decrease in sputum leukocyte density and IL-1beta, IL-8, and LTB4 after fluticasone treatment. The fluticasone group had one and the placebo group three episodes of exacerbation. There were no significant changes in spirometry (p > 0.05) or any reported adverse reactions in either group. The results of this study show that high-dose fluticasone is effective in reducing the sputum inflammatory indices in bronchiectasis. Large-scale and long-term studies are indicated to evaluate the effects of inhaled steroid therapy on the inflammatory components in bronchiectasis.

Topics: Administration, Inhalation; Administration, Topical; Adult; Androstadienes; Anti-Inflammatory Agents; Bronchiectasis; Double-Blind Method; Female; Fluticasone; Forced Expiratory Volume; Glucocorticoids; Humans; Inflammation; Interleukin-1; Interleukin-8; Leukocyte Count; Leukotriene B4; Male; Middle Aged; Nebulizers and Vaporizers; Peak Expiratory Flow Rate; Placebos; Pseudomonas aeruginosa; Sputum; Tumor Necrosis Factor-alpha; Vital Capacity

To determine the efficacy of salmeterol alone in a group of patients with moderate asthma with nocturnal worsening of symptoms.. Double-blind, randomized, placebo-controlled crossover study.. Tertiary care hospital specializing in respiratory diseases.. Ten patients with nocturnal asthma.. Subjects were randomized to salmeterol, 100 micrograms twice daily, or placebo for 6 weeks with a 1-week washout between treatment periods. Symptoms, nocturnal awakenings, and beta 2-agonist use were recorded daily. Spirometry was performed at weeks 1 and 6 of each period at bedtime and at 4 AM, and methacholine challenge was performed at 4 AM followed by bronchoscopy with BAL. BAL fluid analysis included cell count and differential count, eosinophil cationic protein, Charcot-Leyden crystal protein, leukotriene B4, and thromboxane B2.. The percentage of nights with awakenings decreased significantly with salmeterol (69.8 +/- 8.7% vs 30.6 +/- 10.8% for placebo and salmeterol, respectively; p = 0.02). The percentage of 24-h days with supplemental inhaled beta 2-agonist use significantly decreased with salmeterol (85.9 +/- 9.4% vs 70.4 +/- 10.1% for placebo and salmeterol, respectively; p = 0.04). There were no significant differences in bronchial reactivity, 4 AM FEV1, overnight percentage change in FEV1, or indexes of airway inflammation.. Salmeterol alone improves the number of nocturnal awakenings and supplemental 24-h beta 2-agonist use in nocturnal asthma without significantly altering lung function and airway inflammation.

Topics: Adrenergic beta-Agonists; Adult; Albuterol; Asthma; Blood Proteins; Bronchoalveolar Lavage Fluid; Bronchoconstrictor Agents; Bronchodilator Agents; Bronchoscopy; Cell Count; Circadian Rhythm; Cross-Over Studies; Double-Blind Method; Eosinophil Granule Proteins; Eosinophils; Female; Follow-Up Studies; Forced Expiratory Volume; Glycoproteins; Humans; Inflammation; Inflammation Mediators; Leukotriene B4; Lung; Lysophospholipase; Male; Methacholine Chloride; Placebos; Ribonucleases; Salmeterol Xinafoate; Sleep; Spirometry; Thromboxane B2

The pharmacokinetics (PK) and pharmacodynamics (PD) of ketoprofen (KTP) were studied in calves following intravenous administration of the drug racemate at a dose rate of 3 mg/kg. To evaluate the anti-inflammatory properties of KTP, a model of acute inflammation, consisting of surgically implanted subcutaneous tissue cages stimulated by intracaveal injection of carrageenan, was used. No differences were observed between disposition curves of KTP enantiomers in plasma, exudate or transudate. This indicates that in calves KTP pharmacokinetics is not enantioselective. S(+)- and R(-)- KTP each had a short elimination half-life (t1/2 beta) of 0.42 +/- 0.08 h and 0.42 +/- 0.09 h, respectively. The volume of distribution (Vd) was low, values of 0.20 +/- 0.06 L/kg and 0.22 +/- 0.06 L/kg being obtained for R(-) and S(+)KTP, respectively. Body clearance (ClB) was high, correlating with the short elimination half-life, 0.33 +/- 0.03 L/kg/h [R(-)KTP] and 0.32 +/- 0.04 L/kg/h [S(+)-KTP]. KTP pharmacodynamics was evaluated by determining the effects on serum thromboxane (TxB2), exudate prostaglandin (PGE2), leukotriene (LTB4) and beta-glucuronidase (beta-glu) and bradykinin (BK)-induced oedematous swelling. Effect-concentration inter-relationships were analysed by PK/PD modelling. KTP did not affect exudate LTB4, but inhibition of the other variables was statistically significant. The mean EC50 values for inhibition of serum TxB2, exudate PGE2 and beta-glu and BK-induced swelling were 0.118, 0.086, 0.06 and 0.00029 microgram/mL, respectively. These data indicate that KTP exerted an inhibitory action, not only as expected, on eicosanoid (TxB2 and PGE2) synthesis but also on exudate beta-glu and BK-induced oedema. The EC50 values for these actions indicate that they are likely to contribute to the overall anti-inflammatory effects of KTP in calves. However, claims that KTP inhibits 5-lipoxygenase and thereby blocks the production of inflammatory mediators such as LTB4 were not substantiated. PK/PD modelling has proved to be a useful tool for analysing the in vivo pharmacodynamics of KTP and for providing new approaches to elucidating its mechanism(s) of action.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Bradykinin; Carrageenan; Cattle; Cattle Diseases; Cross-Over Studies; Diffusion Chambers, Culture; Dinoprostone; Dose-Response Relationship, Drug; Edema; Glucuronidase; Half-Life; Inflammation; Injections, Intravenous; Ketoprofen; Leukotriene B4; Male; Stereoisomerism; Thromboxane B2

To evaluate the effects of dexamethasone on pulmonary inflammation and permeability in preterm infants at high risk for chronic lung disease (birth weight < 1200 gm), we assessed tracheobronchial aspirate fluid for chemotactic activity and concentrations of mediators of inflammation. In a prospective study, 21 infants still undergoing mechanical ventilation at day 10 of postnatal age who required a fraction of inspired oxygen > or = 0.3, a peak inspiratory pressure > or = 16 cm H2O, or both were randomly assigned to treatment with dexamethasone at day 10 (early treatment group, n = 10) or day 16 (late treatment group, n = 11). The groups were compared with respect to all measurements on day 15; the late treatment group served as a control group. Additionally, the effects of dexamethasone within both groups were evaluated. In the early treatment group, the chemotactic response of peripheral blood neutrophils exposed to tracheobronchial aspirate fluid was significantly reduced 5 days after initiation of dexamethasone treatment compared with pretreatment values of the late treatment group (median (25th to 75th percentile): migratory distance before dexamethasone, 149 microns (140 to 173 microns); after dexamethasone, 81 microns (68 to 114 microns); p < 0.01). In addition, the following values were decreased after dexamethasone therapy in the early treatment group: number of neutrophils in tracheobronchial aspirate fluid (p < 0.05), and concentrations of leukotriene B4 (p < 0.01), interleukin-1 (p < 0.01), elastase-alpha 1-proteinase inhibitor (p < 0.01), and albumin (p < 0.01). Free elastase activity was found in only two infants; detectable activity of protective alpha 1-proteinase inhibitor was present in the others. Analysis of dexamethasone effects within the groups showed that all measurements were significantly decreased after both the early and the late treatment regimens, with the exception of leukotriene B4 and interleukin-1, which declined only after early dexamethasone treatment. Our results indicate that the pulmonary inflammatory response and microvascular permeability are decreased by dexamethasone, which affects the release of inflammatory mediators and neutrophil influx into the airways of preterm infants who require mechanical ventilation.

Topics: Albumins; alpha 1-Antitrypsin; Bronchi; Chemotaxis, Leukocyte; Chronic Disease; Dexamethasone; Humans; Infant, Newborn; Infant, Premature, Diseases; Inflammation; Interleukin-1; Leukotriene B4; Lung; Lung Diseases; Neutrophils; Pancreatic Elastase; Prospective Studies; Risk Factors; Suction; Trachea

The leukocyte NADPH oxidase 2 (NOX2) regulates inflammation independent of its antimicrobial activity. Inherited defects in NOX2 lead to chronic granulomatous disease (CGD), associated with recurrent bacterial and fungal infections, often with excessive neutrophilic inflammation that results in significant inflammatory burden and tissue damage. We previously showed that excessive leukotriene B4 (LTB4) production by NOX2-deficient mouse neutrophils was a key driver of elevated lung neutrophil infiltration in the initial response to pulmonary challenge with the model fungal particle zymosan. We now identify interleukin-1β (IL-1β) and downstream granulocyte colony-stimulating factor (G-CSF) as critical amplifying signals that augment and sustain neutrophil accrual in CGD mice. Neutrophils, delivered into the lung via LTB4, were the primary source of IL-1β within the airways, and their increased numbers in CGD lungs led to significantly elevated local and plasma G-CSF. Elevated G-CSF simultaneously promoted increased granulopoiesis and mobilized the release of higher numbers of an immature CD101- neutrophil subset from the marrow, which trafficked to the lung and acquired a significantly more proinflammatory transcriptome in CGD mice compared with wild-type mice. Thus, neutrophil-produced IL-1β and downstream G-CSF act sequentially but nonredundantly with LTB4 to deploy neutrophils and amplify inflammation in CGD mice after inhalation of zymosan. NOX2 plays a critical role in dampening multiple components of a feed-forward pipeline for neutrophil recruitment, and these findings highlight NOX2 as a key regulator of neutrophil number, subsets, and function at inflamed sites.

Topics: Animals; Granulocyte Colony-Stimulating Factor; Granulomatous Disease, Chronic; Inflammation; Interleukin-1beta; Leukotriene B4; Mice; NADPH Oxidase 2; NADPH Oxidases; Neutrophils; Pneumonia; Zymosan

An imbalance between inflammation-resolving lipid mediators and proinflammatory leukotrienes with the instability of atherosclerotic plaques in experimental models has been reported. However, the contribution of the balance of Resolvin D1 (RvD1) to Leukotriene B4 (LTB4) in predicting acute coronary syndrome (ACS) remains unknown. This study investigated the association of RvD1-to-LTB4 ratio with ACS.Eighty-one patients with ACS and 90 stable coronary artery disease (SCAD) patients were included in this study. Plasma RvD1 and LTB4 levels were measured with commercial kits.Patients with ACS had higher LTB4 levels, lower RvD1 levels, and a lower RvD1-to-LTB4 ratio than patients with SCAD. History of diabetes mellitus, elevated Troponin I, LTB4, and decreased RvD1-to-LTB4 ratio (odds ratio [OR]: 1.025; 95% confidence interval [CI]: 1.014-1.040; P < 0.001) were independently correlated with ACS. Receiver operating characteristic curve analysis demonstrated that RvD1-to-LTB4 ratio was a potential biomarker for the risk of ACS.A circulating proinflammatory lipid profile, characterized by a low RvD1-to-LTB4 ratio may be associated with ACS in patients with ischemic heart disease.

Topics: Acute Coronary Syndrome; Docosahexaenoic Acids; Humans; Inflammation; Leukotriene B4

Immunoglobulin A (IgA) is mostly considered as a non-inflammatory regulator at mucosal areas. However, previous work of our group showed that IgA can also be involved in disease pathology, because it provides a potent stimulus to activate neutrophils after crosslinking of surface CD89 (FcaRI), resulting in chronic inflammation and tissue damage. IgA (auto)antibodies and neutrophils are key players in various diseases, including blistering skin diseases and rheumatoid arthritis. Therefore, we generated an array of anti-CD89 monoclonal antibodies (mAbs) for therapeutic targeting of CD89. The biological activity of newly developed anti-human CD89 mAbs and their potential therapeutic capacity were investigated.. Human neutrophils were isolated from heparinized healthy donor blood. The ability of anti-CD89 mAbs to bind human neutrophils was investigated by flow cytometry. Furthermore, the capacity of these anti-CD89 mAbs to inhibit IgA-mediated phagocytosis, neutrophil extracellular trap (NET) release and migration was studied. To this end, neutrophils were pre-incubated with/without anti-CD89 mAbs after which they were stimulated with IgA-coated beads. The amount of phagocytosed beads, NET release and migrated neutrophils were subsequently analysed. In parallel, chemoattractant leukotriene B4 and lactoferrin (as a measure for degranulation) release were determined. Finally, the therapeutic potential of our prototypic anti-CD89 mAb clone 10E7 was in vivo tested in anti-mouse collagen XVII human IgA-treated transgenic CD89 mice, a preclinical model for autoimmune linear IgA bullous disease (LABD).. Our results show that all generated anti-CD89 mAbs bound surface CD89 on neutrophils. Although these anti-CD89 mAbs bind to different epitopes on EC1 of CD89, they all have the capacity to inhibit IgA-mediated phagocytosis, neutrophil extracellular trap (NET) release and neutrophil migration. Moreover, IgA mediated leukotriene B4 and lactoferrin release are decreased in supernatant from anti-CD89 mAbs-treated neutrophils. Finally, anti-CD89 mAb clone 10E7, that was selected based on its selective binding profile on tissue micro arrays, reduced anti-mouse collagen XVII hIgA-induced neutrophil influx in an in vivo linear IgA bullous disease (LABD) mice model.. This study clearly indicates that our newly developed anti-CD89 mAbs inhibited IgA-induced neutrophil activation and reduced anti-autoantigen IgA-induced neutrophil influx in vivo, supporting further clinical development for the treatment of LABD.

Topics: Animals; Autoimmunity; Immunoglobulin A; Inflammation; Lactoferrin; Leukotriene B4; Mice

Leukotriene B4 receptor type 1 (BLT1), a high-affinity receptor for leukotriene B4 (LTB4), plays an important role in inflammatory responses, including allergic airway inflammation. In this study, we examined the effect of genetic BLT1 deletion (BLT1KO) on ovalbumin (OVA)-induced allergic enteritis in mice to determine the pathogenic role of LTB4/BLT1 in allergic enteritis, a gastrointestinal form of food allergy. Repeated oral OVA challenges after sensitization with OVA and aluminium potassium sulphate induced allergic enteritis, characterized by systemic allergic symptoms (scratching, immobility and swelling), diarrhoea, colonic oedema and colonic goblet cell hyperplasia, accompanied by increased colonic peroxidase activity, colonic inflammatory cytokine expression and increased serum OVA-specific IgE levels. The severity of enteritis was significantly attenuated in BLT1KO mice compared with wild-type (WT) mice, without an increase in serum OVA-specific IgE levels. The accumulation of neutrophils, eosinophils, M2-macrophages, dendritic cells, CD4+ T cells and mast cells was observed in the colonic mucosa of allergic enteritis, and such accumulation was significantly lower in BLT1KO mice than in WT mice. BLT1 expression was upregulated and colocalized mostly in neutrophils and partly in eosinophils and dendritic cells in the colonic mucosa of allergic enteritis. These findings indicate that BLT1 deficiency ameliorates OVA-induced allergic enteritis in mice and that LTB4/BLT1 contributes to neutrophil and eosinophil accumulation in the allergic colonic mucosa. Therefore, BLT1 is a promising drug target for treating food allergies.

Topics: Animals; Immunoglobulin E; Inflammation; Leukotriene B4; Mice; Mice, Knockout; Ovalbumin; Receptors, Leukotriene B4

Inflammation and oxidative stress play a key role in the development of bronchopulmonary dysplasia (BPD), possibly contributing to persistent respiratory morbidity after preterm birth. We aimed to assess if inflammatory markers were elevated in exhaled breath condensate (EBC) of infants born very prematurely (< 32 weeks gestation) at 12-16 corrected months of age, and if increased levels were associated with BPD diagnosis and respiratory morbidity.. EBC samples and respiratory questionnaires were collected from 15 term-born infants and 33 preterm-born infants, 12 with a neonatal BPD diagnosis. EBC samples were analysed for leukotriene B4 (inflammation) and 8-isoprostane (oxidative stress) concentrations using enzyme-linked immune-assays. Differences between groups were analysed by Kruskal-Wallis Test with post-hoc comparisons, independent samples t-test or Mann-Whitney U test depending on normality of the data.. Leukotriene B4 and 8-isoprostane levels were elevated in exhaled breath condensate of preterm-born infants compared to those born at term (mean difference [95% CI]; 1.52 [0.45, 2.59], p = 0.02; 0.77 [0.52, 1.02], p < 0.001, respectively). Leukotriene B4 and 8-isoprostane levels were independent of BPD diagnosis and respiratory morbidity over the first year of life.. Infants born very prematurely exhibit elevated markers of airway neutrophilic inflammation and oxidative stress beyond the first year of life, regardless of a neonatal diagnosis of chronic lung disease or respiratory morbidity during infancy. These findings may have implications for future lung health.. N/A.

Topics: Breath Tests; Bronchopulmonary Dysplasia; Female; Humans; Infant; Infant, Newborn; Infant, Premature; Inflammation; Leukotriene B4; Premature Birth

Persistent and chronic unresolved inflammation exerts a critical role in developing atherosclerosis; however, mechanisms that prevent the resolution of inflammation in atherosclerosis are poorly delineated. This study aims to evaluate the serum levels of inflammatory high-sensitivity C-reactive protein (hsCRP), pro-inflammatory leukotriene B4 (LTB4), besides anti-inflammatory compounds, including eicosapentaenoic acid (EPA) and its derivative resolvin E1 (RvE1) in patients with atherosclerosis. Thirty-four atherosclerosis patients and thirty-two age- and sex-matched healthy individuals were included in this study. The serum levels of hsCRP, LTB4, EPA, and RvE1 were measured using the enzyme-linked immunosorbent assay (ELISA) technique. Our results showed that the hsCRP serum levels in the three-vessel disease (3VD) subgroup of patients are significantly lower than those in the mild and single-vessel disease (SVD) subgroups (P < 0.05). Besides, the serum levels of LTB4 were meaningfully greater in patients with atherosclerosis compared to healthy controls (P < 0.05). Also, the serum EPA and RvE1 levels were significantly higher in patients than in controls (P < 0.01 and P < 0.05, respectively). However, the ratio of RvE1 to LTB4 (RvE1:LTB4) in patients was significantly reduced to that in controls (P < 0.0001). These findings illustrate that imbalanced pro-resolving RvE1 and pro-inflammatory LTB4 might contribute to failing vascular inflammation resolution and subsequent progression toward chronic inflammation in atherosclerosis.

Topics: Atherosclerosis; C-Reactive Protein; Eicosapentaenoic Acid; Humans; Inflammation; Leukotriene B4

Pulmonary tuberculosis (TB) inflammation is an underestimated disease complication which anti-inflammatory drugs may alleviate. This study explored the potential use of the COX-2 inhibitors acetylsalicylic acid (ASA) and celecoxib in 12 TB patients and 12 healthy controls using a whole-blood ex vivo model where TNFα, PGE2, and LTB4 plasma levels were quantitated by ELISA; we also measured COX-2, 5-LOX, 12-LOX, and 15-LOX gene expression. We observed a significant TNFα production in response to stimulation with LPS or M. tuberculosis (Mtb). Celecoxib, but not ASA, reduced TNFα and PGE2 production, while increasing LTB4 in patients after infection with Mtb. Gene expression of COX-2 and 5-LOX was higher in controls, while 12-LOX was significantly higher in patients. 15-LOX expression was similar in both groups. We concluded that COX-2 inhibitors downregulate inflammation after Mtb infection, and our methodology offers a straightforward time-efficient approach for evaluating different drugs in this context. Further research is warranted to elucidate the underlying mechanisms and assess the potential clinical benefit.

Topics: Celecoxib; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Dinoprostone; Humans; Immunity; Inflammation; Leukotriene B4; Mycobacterium tuberculosis; Tuberculosis; Tumor Necrosis Factor-alpha

Leukotriene B4 (LTB4) is a potent chemoattractant that can recruit and activate immune cells such as neutrophils, eosinophils, and monocytes to sites of inflammation. Excessive production of LTB4 has been linked to acute and chronic inflammatory diseases, including asthma, rheumatoid arthritis, and psoriasis. Inhibiting the binding of LTB4 to its receptors, BLT1 and BLT2, is a potential strategy for treating these conditions. While several BLT1 antagonists have been developed for clinical trials, most have failed due to efficacy and safety issues. Therefore, discovering selective BLT2 antagonists could improve our understanding of the distinct functions of BLT1 and BLT2 receptors and their pharmacological implications. In this study, we aimed to discover novel BLT2 antagonists by synthesizing a series of biphenyl analogues based on a BLT2 selective agonist, CAY10583. Among the synthesized compounds, 15b was found to selectively inhibit the chemotaxis of CHO-BLT2 cells with an IC

Topics: Animals; Arthritis, Rheumatoid; Asthma; CHO Cells; Cricetinae; Inflammation; Leukotriene B4; Mice; Receptors, Leukotriene B4

Ganoderma, a fungal genus, is a traditional medicine with immuno-modulating effects. Asthma is an inflammatory disease of airways, and the main trigger of asthma is allergic inflammation. In this study, the effects of Ganoderma (an anti-inflammatory agent) given via oral administration (G/O) or intraperitoneal injection (G/IP) on asthma was evaluated. Forty BALB/c mice were divided into four groups, including the control, OVA-challenge, OVA-challenge + G/O, and OVA-challenge + G/IP. To determine AHR, the MCh challenge test was done. The levels of IL-1β, -4, -5, -6, -8, -10, -12, -13, -17, -25, -33, -38, Cys-LT, LTB4, and hydroxyproline were measured. Finally, lung histopathology was evaluated to determine eosinophilic inflammation, goblet cell hyperplasia, and mucus hyper-secretion. Treatment with G/O and G/IP could significantly reduce the levels of IL-1β, -5, -6, -8, -17, -25, -33, and -38; the levels of IL-4 and IL-13 had no significant changes, but the levels of IL-10 and IL-12 were enhanced. The mice treated with G/O and G/IP showed decreased levels of Cys-LT, LTB4, peribronchial and perivascular inflammation, but no significant changes were observed in AHR, hydroxyproline level, goblet cell hyperplasia, and mucus hyper-secretion. Ganoderma can be applied as an immunomodulatory and anti-inflammatory agent for managing asthma.

Topics: Animals; Anti-Inflammatory Agents; Asthma; Bronchoalveolar Lavage Fluid; Cytokines; Disease Models, Animal; Ganoderma; Hydroxyproline; Hyperplasia; Inflammation; Leukotriene B4; Lung; Mice; Mice, Inbred BALB C; Ovalbumin

Leukotriene B4 receptor 1 (BLT1) plays crucial roles in the acute inflammatory responses and is a valuable target for anti-inflammation treatment, however, the mechanism by which leukotriene B4 (LTB4) activates receptor remains unclear. Here, we report the cryo-electron microscopy (cryo-EM) structure of the LTB4 -bound human BLT1 in complex with a G

Topics: Cryoelectron Microscopy; GTP-Binding Proteins; Humans; Inflammation; Leukotriene B4; Receptors, Leukotriene B4; Signal Transduction; Structure-Activity Relationship

Topics: Animals; Anti-Allergic Agents; Asthma; Cytokines; Disease Models, Animal; Immunoglobulin E; Inflammation; Leukotriene B4; Leukotriene C4; Lung; Mice; Mice, Inbred BALB C; Mucoproteins; Respiratory Hypersensitivity

There is a sex bias in tuberculosis's severity, prevalence, and pathogenesis, and the rates are higher in men. Immunological and physiological factors are fundamental contributors to the development of the disease, and sex-related factors could play an essential role in making women more resistant to severe forms of the disease. In this study, we evaluated sex-dependent differences in inflammatory markers. Serum samples were collected from 34 patients diagnosed with pulmonary TB (19 male and 15 female) and 27 healthy controls (18 male and 9 female). Cytokines IL2, IL4, IL6, IL8, IL10, IFNγ, TNFα, and GM-CSF, and eicosanoids PGE2, LTB4, RvD1, and Mar1 were measured using commercially available immunoassays. The MDA, a product of lipidic peroxidation, was measured by detecting thiobarbituric-acid-reactive substances (TBARS). Differential inflammation patterns between men and women were observed. Men had higher levels of IL6, IL8, and TNFα than women. PGE2 and LTB4 levels were higher in patients than healthy controls, but there were no differences for RvD1 and Mar1. Women had higher RvD1/PGE2 and RvD1/LTB4 ratios among patients. RvD1 plays a vital role in resolving the inflammatory process of TB in women. Men are the major contributors to the typical pro-inflammatory profile observed in the serum of tuberculosis patients.

Topics: Dinoprostone; Eicosanoids; Female; Humans; Inflammation; Interleukin-6; Interleukin-8; Leukotriene B4; Male; Tuberculosis; Tuberculosis, Pulmonary; Tumor Necrosis Factor-alpha

Patients with diabetes present a persistent inflammatory process, leading to impaired wound healing. Since nonhealing diabetic wound management shows limited results, the introduction of advanced therapies targeting and correcting the inflammatory status of macrophages in chronic wounds could be an effective therapeutic strategy to stop the sustained inflammation and to return to a healing state. In an excisional skin injury in a diet-induced diabetic murine model, we demonstrate that topical administration of low-dose aspirin (36 μg/wound/day) improves cutaneous wound healing by increasing wound closure through the promotion of the inflammation resolution program of macrophages. This treatment increased efferocytosis of wound macrophages from aspirin-treated diabetic mice compared with untreated diabetic mice. We also show that aspirin treatment of high-fat-fed mice oriented the phenotype of wound macrophages toward an anti-inflammatory and proresolutive profile characterized by a decrease of LTB4 production. The use of diabetic mice deficient for 5-LOX or 12/15-LOX demonstrated that these two enzymes of acid arachidonic metabolism are essential for the beneficial effect of aspirin on wound healing. Thus, aspirin treatment modified the balance between pro- and anti-inflammatory eicosanoids by promoting the synthesis of proresolving LXA4 through 5-LOX, LTA4, 12/15-LOX signaling. In conclusion, the restoration of an anti-inflammatory and proresolutive phenotype of wound macrophages by the topical administration of low-dose aspirin represents a promising therapeutic approach in chronic wounds.

Topics: Administration, Topical; Animals; Anti-Inflammatory Agents; Aspirin; Diabetes Mellitus, Experimental; Inflammation; Leukotriene A4; Leukotriene B4; Lipoxins; Macrophages; Mice; Phenotype; Skin; Wound Healing

Placental infection and inflammation are risk factors for adverse pregnancy outcomes, including preterm labor. However, the mechanisms underlying these outcomes are poorly understood.. To study this response, we have employed a pregnant mouse model of placental infection caused by the bacterial pathogen Listeria monocyogenes, which infects the human placenta. Through in vivo bioluminescence imaging, we confirm the presence of placental infection and quantify relative infection levels. Infected and control placentas were collected on embryonic day 18 for RNA sequencing to evaluate gene expression signatures associated with infection by Listeria.. We identified an enrichment of genes associated with eicosanoid biosynthesis, suggesting an increase in eicosanoid production in infected tissues. Because of the known importance of eicosanoids in inflammation and timing of labor, we quantified eicosanoid levels in infected and uninfected placentas using semi-targeted mass spectrometry. We found a significant increase in the concentrations of several key eicosanoids: leukotriene B4, lipoxin A4, prostaglandin A2, prostaglandin D2, and eicosatrienoic acid.. Our study provides a likely explanation for dysregulation of the timing of labor following placental infection. Further, our results suggest potential biomarkers of placental pathology and targets for clinical intervention.

Topics: Animals; Biomarkers; Female; Humans; Infant, Newborn; Inflammation; Leukotriene B4; Listeria monocytogenes; Listeriosis; Mice; Placenta; Pregnancy; Pregnancy Complications, Infectious; Prostaglandin D2; Transcriptome

Leukotriene B4 (LTB4) is a potent lipid mediator involved in the recruitment and activation of neutrophils, which is an important feature of tissue injury and inflammation. The biological effects of LTB4 are primarily mediated through the high-affinity LTB4 receptor, BLT1. Postoperative incisional pain is characterized by persistent acute pain at the site of tissue injury and is associated with local inflammation. Here, we compared the role of LTB4-BLT1 signaling in postoperative incisional pain between BLT1-knockout (BLT1KO) and wild-type (BLT1WT) mice. A planter incision model was developed, and mechanical pain hypersensitivity was determined using the von Frey test before and after incision. Local infiltration of neutrophils and inflammatory monocytes was quantified by flow cytometry. Inflammatory cytokine levels in the incised tissue were also determined. Mechanical pain hypersensitivity was significantly reduced in BLT1KO mice compared to BLT1WT mice at 2, 3, and 4 days after incision. LTB4 levels in the tissue at the incision site peaked 3 hours after the incision. Infiltrated neutrophils peaked 1 day after the incision in both BLT1KO and BLT1WT mice. The accumulation of inflammatory monocytes increased 1-3 days after the incision and was significantly more reduced in BLT1KO mice than in BLT1WT mice. In BLT1KO mice, Interleukin-1β and Tumor Necrosis Factor-α levels 1 day after the incision were significantly lower than those of BLT1WT mice. Our data suggest that LTB4 is produced and activates its receptor BLT1 in the very early phase of tissue injury, and that LTB4-BLT1 signaling exacerbates pain responses by promoting local infiltration of inflammatory monocytes and cytokine production. Thus, LTB4-BLT1 signaling is a potential target for therapeutic intervention of acute and persistent pain induced by tissue injury.

Topics: Animals; Cytokines; Hypersensitivity; Inflammation; Interleukin-1beta; Leukotriene B4; Mice; Mice, Knockout; Nociception; Pain; Receptors, Leukotriene B4; Tumor Necrosis Factor-alpha

The goal of this work is to explore if the changes induced by d-fagomine in the gut microbiota are compatible with its effect on body weight and inflammation markers in rats. Methods: Sprague Dawley rats were fed a standard diet supplemented with d-fagomine (or not, for comparison) for 6 months. The variables measured were body weight, plasma mediators of inflammation (hydroxyeicosatetraenoic acids, leukotriene B4, and IL-6), and the concentration of acetic acid in feces and plasma. The composition and diversities of microbiota in cecal content and feces were estimated using 16S rRNA metabarcoding and high-throughput sequencing. We found that after just 6 weeks of intake d-fagomine significantly reduced body weight gain, increased the plasma acetate concentration, and reduced the plasma concentration of the pro-inflammatory biomarkers' leukotriene B4, interleukin 6 and 12 hydroxyeicosatetraenoic acids. These changes were associated with a significantly increased prevalence of

Topics: Animals; Body Weight; Dietary Fiber; Feces; Gastrointestinal Microbiome; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; Rats; Rats, Sprague-Dawley; RNA, Ribosomal, 16S

Exposure to cigarette smoke complicates the treatment and management of asthma through a variety of inflammatory effects. This study aimed to investigate the differences between newly diagnosed cases of asthma in smokers and nonsmokers in terms of localized and systemic biomarkers following treatment with inhaled corticosteroids (ICS) or ICS in combination with a long-acting β2 agonist (LABA).. Specimens of exhaled breath condensate (EBC) from newly diagnosed patients with asthma were used to quantify inflammation in the airways, while blood samples were used to assess systemic inflammation. In both samples, the levels of IL-6, LTB4, LTD4, and 8-isoprostane were measured and these were repeated after 3 months of treatment with ICS or ICS + LABA.. Monitoring the alterations in 8-isoprostane levels in EBC in patients with asthma who smoke may be helpful in deciding on therapeutic management and switching treatments. Asthma control was better in nonsmokers than in smokers.

Topics: Adrenal Cortex Hormones; Asthma; Biomarkers; Breath Tests; Exhalation; Humans; Inflammation; Interleukin-6; Leukotriene B4; Leukotriene D4; Smoking

Leukotriene B

Topics: Animals; Biomarkers; Cell Differentiation; Cell Membrane; Cell Movement; Cell Proliferation; Chemokine CCL21; Dendritic Cells; Dermatitis, Atopic; Hypersensitivity; Inflammation; Interleukin-12; Leukotriene B4; Lymph Nodes; Mice, Inbred C57BL; Receptors, Leukotriene B4; Skin; Th1 Cells; Transcriptome

Apolipoprotein E4 (APOE4) is associated with a greater response to neuroinflammation and the risk of developing late-onset Alzheimer's disease (AD), but the mechanisms for this association are not clear. The activation of calcium-dependent cytosolic phospholipase A. Mouse primary astrocytes, mouse and human brain samples differing by APOE genotypes were collected for measuring cPLA2 expression, phosphorylation, and activity in relation to measures of inflammation and oxidative stress.. Our findings implicate greater activation of cPLA2 signaling system with APOE4, which could represent a potential drug target for mitigating the increased neuroinflammation with APOE4 and AD.

Topics: Amyloid beta-Peptides; Animals; Apolipoprotein E3; Apolipoprotein E4; Astrocytes; Calcium; Cerebral Cortex; Enzyme Activation; Heterozygote; Humans; Inflammasomes; Inflammation; Leukotriene B4; MAP Kinase Signaling System; Mice; Mice, Transgenic; Neurons; NF-kappa B; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Peptide Fragments; Phospholipases A2, Cytosolic; Phosphorylation; Protein Processing, Post-Translational; Reactive Oxygen Species; Synaptosomes

Production of the proinflammatory cytokine tumor necrosis factor (TNF) must be precisely regulated for effective host immunity without the induction of collateral tissue damage. Here, we showed that TNF production was driven by a spleen-liver axis in a rat model of systemic inflammation induced by bacterial lipopolysaccharide (LPS). Analysis of cytokine expression and secretion in combination with splenectomy and hepatectomy revealed that the spleen generated not only TNF but also factors that enhanced TNF production by the liver, the latter of which accounted for nearly half of the TNF secreted into the circulation. Using mass spectrometry-based lipidomics, we identified leukotriene B

Topics: Animals; Inflammation; Leukotriene B4; Lipopolysaccharides; Liver; Rats; Spleen; Tumor Necrosis Factor-alpha

Neutrophils communicate with each other to form swarms in infected organs. Coordination of this population response is critical for the elimination of bacteria and fungi. Using transgenic mice, we found that neutrophils have evolved an intrinsic mechanism to self-limit swarming and avoid uncontrolled aggregation during inflammation. G protein-coupled receptor (GPCR) desensitization acts as a negative feedback control to stop migration of neutrophils when they sense high concentrations of self-secreted attractants that initially amplify swarming. Interference with this process allows neutrophils to scan larger tissue areas for microbes. Unexpectedly, this does not benefit bacterial clearance as containment of proliferating bacteria by neutrophil clusters becomes impeded. Our data reveal how autosignaling stops self-organized swarming behavior and how the finely tuned balance of neutrophil chemotaxis and arrest counteracts bacterial escape.

Topics: Animals; Cell Aggregation; Chemokine CXCL2; Chemotaxis, Leukocyte; Eosinophils; Female; G-Protein-Coupled Receptor Kinase 2; Inflammation; Leukotriene B4; Lymph Nodes; Male; Mice; Mice, Transgenic; Neutrophils; Pseudomonas aeruginosa; Pseudomonas Infections; Receptors, G-Protein-Coupled; Signal Transduction; Skin

Dexamethasone is an antiemetic that is frequently administered before or after the induction of anesthesia for prevention and treatment of perioperative nausea and vomiting. Dexamethasone has anti-inflammatory and immunosuppressive effects primarily via suppression of expression of inflammatory mediators. However, its effect on the eicosanoids and docosanoids that mediate the inflammatory response and inflammation resolution are unclear. We aimed to assess the effect of a single dose of intra-operative dexamethasone on peri‑operative eicosanoids involved in inflammation including leukotriene B. A subgroup of 80 patients from the randomised controlled PADDAG trial was enrolled into this substudy. They were allocated to receive 0, 4 or 8 mg dexamethasone administered intravenously at induction of anesthesia. Blood samples were collected before and 24 h after dexamethasone, for measurement of leukocytes, hs-CRP, LTB. Compared to the administration of placebo, neutrophil count was elevated (P<0.05) 24 h after administration of 4 and 8 mg dexamethasone. Dexamethasone (8 mg) resulted in increased levels of LTB. Antiemetic doses of dexamethasone given during surgery increased plasma LTB

Topics: Adult; Antiemetics; C-Reactive Protein; Dexamethasone; Docosahexaenoic Acids; Eicosanoids; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; Female; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Leukocyte Count; Leukotriene B4; Lymphocyte Count; Male; Middle Aged; Neutrophils; Perioperative Care

Omega-3 and omega-6 fatty acids can be endogenously converted into mediators with pro-inflammatory (eg, leukotriene B4/LTB4) or anti-inflammatory/pro-resolving activities (eg, resolvin D1/RvD1 and maresin 1/MaR1). Recent data indicate an imbalance of LTB4 and MaR1 levels in pre-eclampsia (PE), but the relative production of these mediators, including RvD1, and the role of these mediators in the disease pathogenesis remain unclear. Therefore, this study aimed to investigate the plasma levels of LTB4, RvD1, and MaR1 in pregnant women with or without PE and non-pregnant controls and their association with clinical/laboratory parameters of PE women.. LTB4, RvD1, and MaR1 plasma levels were measured by competitive enzyme immunoassay in 19 non-pregnant, 20 normotensive pregnant, and 21 PE women.. Plasma concentrations of LTB4 were higher and RvD1 were lower in PE women than in normotensive pregnant women, who presented higher levels of LTB4 and similar levels of RvD1 to non-pregnant women. MaR1 levels did not differ among the groups. Pre-eclampsia women had decreased RvD1/LTB4 and MaR1/LTB4 ratios. Considering only the PE group, positive correlations were observed among all the mediators tested, between LTB4 and white blood cell count and between RvD1 and creatinine levels. However, all lipid mediators correlated negatively with body mass index before pregnancy. LTB4 also correlated negatively with maternal age.. Our findings suggest that the PE state results in systemic overproduction of LTB4 in relation to RvD1 and MaR1, and that these lipid mediators may be involved with the disease pathogenesis.

Topics: Adult; Body Mass Index; Docosahexaenoic Acids; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Female; Humans; Inflammation; Inflammation Mediators; Leukotriene B4; Pre-Eclampsia; Pregnancy; Young Adult

Topics: Adult; Aged; Aged, 80 and over; Animals; Antigens, Ly; Arachidonate 5-Lipoxygenase; Chemokine CCL2; Colitis; Colon; Down-Regulation; Female; Humans; Inflammasomes; Inflammation; Inflammatory Bowel Diseases; Interleukin-1beta; Intestines; Lectins, C-Type; Leukotriene B4; Macrophages; Male; Mannose Receptor; Mannose-Binding Lectins; Mice, Inbred C57BL; Middle Aged; Receptors, CCR2; Receptors, Cell Surface; Signal Transduction; Young Adult

Leukotriene B

Topics: Animals; Disease Models, Animal; Inflammation; Leukotriene B4; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Receptors, Leukotriene B4; Signal Transduction

Hidradenitis suppurativa (HS) is a chronic, recurring inflammatory dermatosis characterized by abscesses, deep-seated nodules, sinus tracts, and fibrosis in skin lesions around hair follicles of the axillary, inguinal, and anogenital regions. Whereas the exact pathogenesis remains poorly defined, clear evidence suggests that HS is a multifactorial inflammatory disease characterized by innate and adaptive immune components. Bioactive lipids are important regulators of cutaneous homeostasis, inflammation, and resolution of inflammation. Alterations in the lipid mediator profile can lead to malfunction and cutaneous inflammation. We used targeted lipidomics to analyze selected omega-3 and omega-6 polyunsaturated fatty acids in skin of patients with HS and of healthy volunteers. Lesional HS skin displayed enrichment of 5-lipoxygenase (LO)‒derived metabolites, especially leukotriene B4. In addition, 15-LO‒derived metabolites were underrepresented in HS lesions. Changes in the lipid mediator profile were accompanied by transcriptomic dysregulation of the 5-LO and 15-LO pathways. Hyperactivation of the 5-LO pathway in lesional macrophages identified these cells as potential sources of leukotriene B4, which may cause neutrophil influx and activation. Furthermore, leukotriene B4-induced mediators and pathways were elevated in HS lesions, suggesting a contribution of this proinflammatory lipid meditator to the pathophysiology of HS.

Topics: Adult; Aged; Arachidonate 15-Lipoxygenase; Arachidonate 5-Lipoxygenase; Biopsy; Cells, Cultured; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Female; Gene Expression Profiling; Hidradenitis Suppurativa; Humans; Inflammation; Leukotriene B4; Lipid Metabolism; Lipidomics; Male; Middle Aged; Primary Cell Culture; Signal Transduction; Skin; Up-Regulation; Young Adult

Topics: Animals; Endosomes; Humans; Inflammation; JNK Mitogen-Activated Protein Kinases; Leukotriene B4; Lipid Metabolism; Molecular Targeted Therapy; Neutrophils; Pneumonia; Signal Transduction; Silicon Dioxide; Silicosis

Oxazolidinone hydroxamic acid derivatives were synthesised and evaluated for inhibitory activity against leukotriene (LT) biosynthesis in three

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonate 5-Lipoxygenase; Cell Line; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Humans; Hydroxamic Acids; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred BALB C; Molecular Structure; Oxazolidinones; Structure-Activity Relationship; Zymosan

The eicosanoid leukotriene B4 (LTB4) relays chemotactic signals to direct neutrophil migration to inflamed sites through its receptor BLT1. However, the mechanisms by which the LTB4-BLT1 axis relays chemotactic signals during intravascular neutrophil response to inflammation remain unclear. Here, we report that LTB4 produced by neutrophils acts as an autocrine/paracrine signal to direct the vascular recruitment, arrest, and extravasation of neutrophils in a sterile inflammation model in the mouse footpad. Using intravital subcellular microscopy, we reveal that LTB4 elicits sustained cell polarization and adhesion responses during neutrophil arrest in vivo. Specifically, LTB4 signaling coordinates the dynamic redistribution of non-muscle myosin IIA and β2-integrin, which facilitate neutrophil arrest and extravasation. Notably, we also found that neutrophils shed extracellular vesicles in the vascular lumen and that inhibition of extracellular vesicle release blocks LTB4-mediated autocrine/paracrine signaling required for neutrophil arrest and extravasation. Overall, we uncover a novel complementary mechanism by which LTB4 relays extravasation signals in neutrophils during early inflammation response.

Topics: Animals; Autocrine Communication; CD18 Antigens; Cell Movement; Chemotactic Factors; Humans; Inflammation; Leukotriene B4; Mice; Neutrophils; Nonmuscle Myosin Type IIA; Paracrine Communication; Receptors, Leukotriene B4

Topics: Animals; Anti-Inflammatory Agents; Diet, High-Fat; Eicosapentaenoic Acid; Gene Expression Profiling; Gene Expression Regulation; Gene Regulatory Networks; Inflammation; Intra-Abdominal Fat; Leukotriene B4; Male; Mice, Inbred C57BL; Mice, Obese; MicroRNAs; Obesity; Receptors, Cell Surface; Signal Transduction; Transcription, Genetic; Transcriptome

To investigate the possible role of Naringenin in AMPK signaling pathway in LPS-induced septic cardiac dysfunction in mice and to elucidate the inherent mechanism.. Male C57 mice were used in the establishment of mouse sepsis model. The effect of Naringenin on septic cardiac dysfunction was observed. Echocardiographic parameters were recorded. Western blot was employed to detect the expressions of BCL-2, BAX, cleaved caspase-3, pNF-kB and IkB-α. Myocardial mitochondria were isolated and extracted. Real-time PCR was applied to detect the expressions of Cox4i, Cox5a mRNA, mt-Nd1, mt-Nd2, mt-Co1 and mt-Co2 mRNA. Western blot was employed to detect the expressions of Complex I, Complex II, and OPA1 to evaluate the effects of Naringenin on myocardial mitochondrial biology and function in septic cardiac dysfunction.. The expressions of TNF-α, IL-6, pNF-κB and IκB-α have changed after Naringenin treatment. IκB-α expression was decreased, expressions of TNF-α, IL-6 and pNF-κB were increased. Naringenin has significantly inhibited AMPK and ACC phosphorylation, and decreased PGC1α expression. Moreover, Naringenin reversed the increased expressions of PGC1α and phosphorylation of AMPK and ACC by U75302 treatment, and decreased the expressions of complex I, complex II and OPA1.. Naringenin inhibits LTB4/BLT1 receptors to attenuate cardiomyocyte inflammation and apoptosis, which may mediate the protective effect of anti-septic cardiac dysfunction by activating AMPK signaling pathway and inhibiting NF-κB signaling and mitochondrial damage.

Topics: Adenylate Kinase; Animals; Apoptosis; Disease Models, Animal; Flavanones; Heart Diseases; Inflammation; Interleukin-6; Leukotriene B4; Lipopolysaccharides; Male; Mice; Myocardium; Myocytes, Cardiac; NF-kappa B; NF-KappaB Inhibitor alpha; Receptors, Leukotriene B4; Sepsis; Signal Transduction; Tumor Necrosis Factor-alpha

This study investigates the participation of PI3Kγ in the development of joint inflammation and dysfunction in an experimental model of acute gout in mice. Acute gout was induced by injection of monosodium urate (MSU) crystals into the tibiofemoral joint of mice. The involvement of PI3Kγ was evaluated using a selective inhibitor and mice deficient for PI3Kγ (PI3Kγ

Topics: Acute Disease; Animals; Arthritis, Gouty; Caspase 1; Cell Adhesion; Cell Movement; Class Ib Phosphatidylinositol 3-Kinase; Cytoplasm; Enzyme Activation; Inflammasomes; Inflammation; Interleukin-1beta; Joints; Leukotriene B4; Male; Mice, Inbred C57BL; Microvessels; Neutrophil Infiltration; Neutrophils; Nociception; Phosphorylation; Proto-Oncogene Proteins c-akt; Synovial Membrane; Uric Acid

This paper reports on the incorporation of oleic acid (OA) within nanostructured lipid carriers (OA-NLC) to improve the anti-inflammatory effects in the presence of albumin.. NLCs produced via hot high-shear homogenization/ultrasonication were characterized in terms of particle size, zeta potential, and toxicity. We examined the effects of OA-NLC on neutrophil activities. Dermatologic therapeutic potential was also elucidated by using a murine model of leukotriene B4-induced skin inflammation.. In the presence of albumin, OA-NLC but not free OA inhibited superoxide generation and elastase release. Topical administration of OA-NLC alleviated neutrophil infiltration and severity of skin inflammation.. OA incorporated within NLC can overcome the interference of albumin, which would undermine the anti-inflammatory effects of OA. OA-NLC has potential therapeutic effects in topical ointments.

Topics: Administration, Topical; Adult; Animals; Calcium; Cattle; Cell Death; Drug Carriers; Humans; Inflammation; Leukotriene B4; Lipids; Male; Mice, Inbred BALB C; Nanostructures; Neutrophil Activation; Neutrophils; Oleic Acid; Pancreatic Elastase; Serum Albumin, Bovine; Skin; Superoxides; Young Adult

Leukotriene B4 (LTB4) is a major pro-inflammatory mediator that leads to the persistence of chronic inflammation in chronic obstructive pulmonary disease (COPD). The purpose of this study was to evaluate therapeutic potential of BLT1 antagonist for cigarette smoke (CS)-induced COPD and to explore the underlying mechanism.. In vitro, autophagy proteins were determined by Western blotting in RAW264.7 macrophages treated with U75302 (BLT1 antagonist) or autophagy inhibitor in cigarette smoke extract-induced inflammation. In vivo, C57BL/6J mice were randomly divided into three groups: Control group, CS group and CS+U75302 group. After 12-week exposure, histological analysis and lung function tests were performed to evaluate the inflammatory infiltration and emphysema. The expression of inflammatory cytokines was measured by real-time PCR and enzyme-linked immunosorbent assay. Immunohistochemical analysis and Western blotting detected the expression of autophagy-related proteins. Transmission electron microscopy (TEM) showed the alterations of autophagosomes and lysosomes.. Lower levels of inflammatory factors and autophagy markers were detected in U75302-treated cells and mice after CS exposure than control. In vitro, LC3 mRNA expression was elevated when treated with U75302. Autophagy inhibition resulted in augmented inflammatory response and autophagy proteins even with U75302 treatment. Furthermore, BLT1 antagonist decreased the number of lysosomes and autophagosomes in alveolar macrophages of mice and potentially enhanced the expression of transcriptional activation of transcription factor-EB (TFEB) in vitro and vivo.. Insufficient autophagy of macrophages was associated with LTB4-mediated inflammation in CS-exposure models. BLT1 antagonist ameliorated inflammatory response through inducing autophagy.

Topics: Animals; Autophagy; Cells, Cultured; Cigarette Smoking; Inflammation; Leukotriene B4; Male; Mice; Mice, Inbred C57BL; Pulmonary Disease, Chronic Obstructive; RAW 264.7 Cells; Receptors, Leukotriene B4

Exhaled breath condensate (EBC) analysis is a noninvasive method to assess the lower respiratory tract. In human subjects, EBC hydrogen peroxide (H. To determine associations between EBC biomarkers and cytological and endoscopic definitions of lower airway inflammation (LAI) while controlling for sampling and environmental variables.. Prospective, cross-sectional study.. EBC pH and H. LAI is challenging to categorise due to a variety of clinical and cytological phenotypes. Although the study was designed to overcome this limitation, numbers of horses were small in some categories.

Topics: Analysis of Variance; Animals; Biomarkers; Breath Tests; Bronchoalveolar Lavage Fluid; Bronchoscopy; Cross-Sectional Studies; Eosinophils; Female; Hemorrhage; Horse Diseases; Horses; Hydrogen Peroxide; Hydrogen-Ion Concentration; Inflammation; Leukotriene B4; Linear Models; Male; Multivariate Analysis; Neutrophils; Prospective Studies; Respiratory System; Respiratory Tract Diseases

Neuromyelitis optica spectrum disorders (NMOSD) are a spectrum of neuroinflammatory disorders associated with autoimmune antibodies against aquaporin-4 (AQP4). Accumulating evidence suggests that inflammation is involved in NMOSD pathogenesis. Resolution of inflammation, which is a highly regulated process mediated by specialized pro-resolving lipid mediators (SPMs) is important to prevent over-responsive inflammation. Deficiency in resolution of inflammation may lead to or accelerates inflammatory diseases. However, whether resolution of inflammation is impaired in NMOSD is not known. The objective of this study was to analyze the levels of SPMs in the serum and cerebrospinal fluid (CSF) of NMOSD patients, and to explore the roles of SPMs in clinical features of NMOSD.. Thirty-five patients with NMOSD, 34 patients with multiple sclerosis, and 36 patients with non-inflammatory neurological diseases were enrolled in this study. Pro-resolving mediators including Annexin A1 (ANXA1) and resolvin D1 (RvD1), as well as pro-inflammatory lipid mediator leukotriene B4 (LTB4) levels were analyzed by enzyme-linked immunosorbent assay. Pro- and anti-inflammatory cytokines as well as chemokine levels were analyzed using cytometric beads array (CBA).. Our results showed RvD1 levels were significantly decreased, whereas LTB4 levels were significantly increased in the CSF of NMOSD patients. AQP4-IgG titer was negatively correlated with RvD1 levels in the CSF of NMOSD patients.. Decreased RvD1 levels indicate impaired resolution of inflammation in NMOSD patients. AQP4-IgG may contribute to increased inflammation and lead to unresolved inflammation in NMOSD.

Topics: Adult; Annexin A1; Aquaporin 4; Blood-Brain Barrier; Docosahexaenoic Acids; Female; Humans; Inflammation; Inflammation Mediators; Leukotriene B4; Male; Neuromyelitis Optica; Retrospective Studies; Severity of Illness Index

Genetic variation in the genes ALOX5 (arachidonate 5-lipoxygenase), ALOX5AP (arachidonate 5-lipoxygenase-activating protein) and LTA4H (leukotriene A4 hydrolase) has previously been shown to contribute to the risk of MI (myocardial infarction) in Caucasian and African American populations. All genes encode proteins playing a role in the synthesis of the pro-inflammatory leukotriene B mediators, possibly providing a link between MI and inflammation. The aim of the present study was to investigate whether these associations could be confirmed in the study of China MI patients. The study included 401 Han Chinese MI patients and 409 controls. Six tag single nucleotide polymorphisms (SNPs)-ALOX5 rs12762303 and rs12264801, ALOX5AP rs10507391, LTA4H rs2072512, rs2540487 and rs2540477-were selected. SNP genotyping was performed by an improved multiplex ligation detection reaction assay.. The rs2540487 genotype was associated with the risk of MI in overdominant model (P = 0.008). rs12762303 and rs10507391 SNPs were significantly associated with lipid levels in MI patients (P < 0.006-0.008). Several SNPs interacted with alcohol consumption, cigarette smoking, and hypertension to modify TC, TG, LDL-C and CRE levels, and the risk of MI (P < 0.0017 for all). No association between the SNPs of LT pathway and susceptibility to MI was found (P > 0.05 for all).. Taken together, this study provides additional evidence that functional genetic variation of the LT pathway can mediate atherogenic processes and the risk of MI in Chinese.

Topics: 5-Lipoxygenase-Activating Proteins; Alcohol Drinking; Arachidonate 5-Lipoxygenase; Atherosclerosis; China; Epoxide Hydrolases; Female; Genetic Association Studies; Genetic Predisposition to Disease; Genotype; Haplotypes; Humans; Inflammation; Leukotriene B4; Male; Metabolic Networks and Pathways; Middle Aged; Myocardial Infarction; Polymorphism, Single Nucleotide; Risk Factors; White People

Topics: Cell Survival; Chemotactic Factors; Chemotaxis, Leukocyte; HL-60 Cells; Humans; Immunity, Innate; Inflammation; Lab-On-A-Chip Devices; Leukotriene B4; Lipopolysaccharides; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils

Various inflammatory eicosanoid levels in biomaterials from airways of asthma and their associations with clinical parameters remain uncertain. We hypothesized that prostaglandin and leukotriene levels differ between in exhaled breath condensates (EBCs) and in sputum in mild, moderate, and severe levels of asthma and that EBC and sputum eicosanoid levels are associated with indexes of pulmonary function and inflammation.. To determine the differences between EBC and sputum eicosanoid levels in healthy participants and patients with asthma with different asthma severity levels.. Collected EBC and sputum, as well as pulmonary function, were examined in adult patients with asthma and healthy participants. Exhaled breath condensate prostaglandin D2-methoxime (PGD2-MOX), cysteinyl leukotrienes (CysLTs), leukotriene B4 (LTB4), and thromboxane B2 levels, and some sputum eicosanoid and tryptase levels were measured. Differences in eicosanoid levels among participants and their associations with pulmonary function and tryptase and granulocyte levels in sputum were then evaluated.. Analysis of 94 EBCs and 43 sputa revealed that EBC and sputum PGD2-MOX and CysLT levels were significantly higher in patients with asthma than in healthy participants. Exhaled breath condensate PGD2-MOX, CysLT, and LTB4 levels were significantly higher in patients with severe asthma. Exhaled breath condensate PGD2-MOX level was also significantly correlated with sputum tryptase levels and lower pulmonary function in patients with asthma. Sputum PGD2-MOX and CysLT levels were significantly correlated with the proportion of eosinophils among all cells in sputum in patients with asthma.. The results suggest that EBC PGD2 levels are associated with impairment of pulmonary function in adults with asthma who have undergone guideline treatment. Exhaled breath condensate or sputum PGD2 and CysLTs may represent severity or airway inflammation in asthma.

Topics: Adult; Asthma; Breath Tests; Cysteine; Eicosanoids; Female; Granulocytes; Humans; Inflammation; Leukotriene B4; Leukotrienes; Lung; Male; Middle Aged; Prostaglandin D2; Sputum; Thromboxane B2; Tryptases

The anti-inflammatory profile of DPA was investigated via a dextran sulphate sodium (DSS)-induced colitis model, and was also compared with those of EPA and DHA. The results showed that DPA could significantly reduce (stronger than EPA and DHA) the disease activity index score, macroscopic appearance score, colon shortening, histological assessment, and myeloperoxidase accumulation in the colon. In addition, DPA also inhibited the abnormal production and mRNA expression of pro-inflammatory cytokines, namely tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 and improved the production and expression of an anti-inflammatory cytokine, IL-10. Furthermore, the molecular mechanisms underlying these effects were also explored through the synthesis pathway of eicosanoids. DPA could inhibit the synthesis of leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) more greatly while differences of cyclooxygenase (COX) and 5-lipoxidase (LOX) contents in these three groups were not significant. We ascribed these effects to the easier incorporation of DPA into inflammatory cells leading to the decrease in the substrate for the synthesis of pro-inflammatory eicosanoids (PGE2 and LTB4). Besides, DPA-derived mediators might also be involved.

Topics: Animals; Anti-Inflammatory Agents; Body Weight; Colitis, Ulcerative; Colon; Cytokines; Dextran Sulfate; Dinoprostone; Disease Models, Animal; Fatty Acids, Unsaturated; Inflammation; Interleukin-1beta; Leukotriene B4; Lipoxygenase; Male; Mice; Plant Extracts; Prostaglandin-Endoperoxide Synthases; RNA, Messenger; Tumor Necrosis Factor-alpha

Leukotriene B4 (LTB4) is a highly potent neutrophil chemoattractant and neutrophils induces inflammatory response and oxidative stress when they recruit to and infiltrate in the injuried/inflamed site, such as the brain parenchyma after aneurysmal subarachnoid hemorrhage (SAH). This study is to investigate the potential effects of inhibition of LTB4 synthesis on neutrophil recruitment, inflammatory response and oxidative stress, as well as early brain injury (EBI) in rats after SAH. A pre-chiasmatic cistern SAH model of rats was used in this experiment. SC 57461A was used to inhibit LTB4 synthesis via intracerebroventricular injection. The brain tissues of temporal lobe after SAH were analyzed. Neuronal injury, brain edema and neurological function were evaluated to investigate the development of EBI. We found that inhibition of LTB4 synthesis after SAH could reduce the level of myeloperoxidase, alleviate the inflammatory response and oxidative stress, and reduce neuronal death in the brain parenchyma, and ameliorate brain edema and neurological behavior impairment at 24h after SAH. These results suggest that inhibition of LTB4 synthesis might alleviate EBI after SAH possibly via reducing the neutrophil-generated inflammatory response and oxidative stress.

Topics: Animals; beta-Alanine; Blood-Brain Barrier; Brain Edema; Brain Injuries; Disease Models, Animal; Inflammation; Leukotriene B4; Male; Neutrophils; Oxidative Stress; Rats, Sprague-Dawley; Subarachnoid Hemorrhage

The aim of this study was to examine the occurrence of five azo food dyes-tartrazine, sunset yellow, carmoisine, allura red, and ponceau 4 R-in the food supply chain of Singapore and their effects on the in vitro synthesis of leukotriene B. Trained personnel recorded the names of foods and beverages sold in a local supermarket that contained at least one of the five azo dyes. The occurrence of the azo dyes in the local food supply was computed. The synthesis of LTB. Of the 1681 processed food items, 194 (11.54%) contained at least one of the five azo dyes. Tartrazine was most prevalent in food and beverage products sold in Singapore, followed by allura red, sunset yellow, ponceau 4 R, and carmoisine. The five azo dyes augmented the in vitro synthesis of LTB. The high prevalence of azo dyes in the food supply of Singapore and their ability to elicit proinflammatory responses in vitro suggest a potential health risk to the local population.

Topics: Azo Compounds; Beverages; F2-Isoprostanes; Food; Food Analysis; Food Coloring Agents; Humans; Inflammation; Leukotriene B4; Naphthalenesulfonates; Neutrophils; Risk Factors; Singapore; Tartrazine

Silicosis is a lung inflammatory disease caused by chronic exposure to crystalline silica (CS). Leukotriene B

Topics: Animals; Cell Line; Humans; Inflammasomes; Inflammation; Interleukin-1beta; Leukotriene B4; Macrophages; Mast Cells; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinase 8; Neutrophils; NLR Family, Pyrin Domain-Containing 3 Protein; Phagosomes; rab GTP-Binding Proteins; rab5 GTP-Binding Proteins; RAW 264.7 Cells; Silicon Dioxide; Silicosis

The potential of omega-3 poly-unsaturated fatty acids (PUFAs) as a therapeutic target for psoriasis, a chronic inflammatory skin disease of IL-23/IL-17 axis, is a long-disputed question, since various epidemiological studies have suggested the association between high-intake of omega-3 PUFAs and the reduced frequency and severity of psoriasis. However, their actual significance and the molecular mechanisms remain largely unknown. To address these issues, we focused on resolvin E1 (RvE1), an omega-3 PUFAs-derived metabolite, and examined its effects on psoriatic dermatitis, using an imiquimod-induced mouse psoriasis model. RvE1 potently suppressed the inflammatory cell infiltration and epidermal hyperplasia in the psoriatic skin. RvE1 decreased the mRNA expression of IL-23 in the skin. Consistently, RvE1 inhibited IL-23 production by dendritic cells (DCs) in vitro. Furthermore, RvE1 exerted inhibitory effects on migration of cutaneous DCs and γδ T cells, a major IL-17-producing cell population in mouse, both in vivo and in vitro. These suppressive effects of RvE1 were mediated by its antagonistic function on BLT1, a receptor of leukotriene B4, and were also observed in human DCs, Th17 and Tc17 cells. Our results indicate a novel mechanism of omega-3 PUFA-mediated amelioration of psoriasis, and suggest a potential of RvE1 as a therapeutic target for psoriasis.

Topics: Animals; Cell Movement; Dendritic Cells; Dermatitis; Disease Models, Animal; Eicosapentaenoic Acid; Fatty Acids, Omega-3; Female; Humans; Inflammation; Interleukin-17; Leukotriene B4; Mice; Mice, Inbred C57BL; Psoriasis; RNA, Messenger; Skin; Th17 Cells

Poorly controlled diabetes leads to comorbidities and enhanced susceptibility to infections. While the immune components involved in wound healing in diabetes have been studied, the components involved in susceptibility to skin infections remain unclear. Here, we examined the effects of the inflammatory lipid mediator leukotriene B4 (LTB4) signaling through its receptor B leukotriene receptor 1 (BLT1) in the progression of methicillin-resistant Staphylococcus aureus (MRSA) skin infection in 2 models of diabetes. Diabetic mice produced higher levels of LTB4 in the skin, which correlated with larger nonhealing lesion areas and increased bacterial loads compared with nondiabetic mice. High LTB4 levels were also associated with dysregulated cytokine and chemokine production, excessive neutrophil migration but impaired abscess formation, and uncontrolled collagen deposition. Both genetic deletion and topical pharmacological BLT1 antagonism restored inflammatory response and abscess formation, followed by a reduction in the bacterial load and lesion area in the diabetic mice. Macrophage depletion in diabetic mice limited LTB4 production and improved abscess architecture and skin host defense. These data demonstrate that exaggerated LTB4/BLT1 responses mediate a derailed inflammatory milieu that underlies poor host defense in diabetes. Prevention of LTB4 production/actions could provide a new therapeutic strategy to restore host defense in diabetes.

Topics: Abscess; Animals; Bacterial Load; Cell Movement; Chemokines; Cytokines; Diabetes Mellitus, Experimental; Female; Inflammation; Leukotriene B4; Macrophages; Male; Methicillin-Resistant Staphylococcus aureus; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Receptors, Leukotriene B4; Signal Transduction; Skin; Staphylococcal Skin Infections

Objective To evaluate the effect of the phenolic compound naringenin on thermal burn-induced inflammatory responses and oxidative stress in rats. Methods First degree thermal burn injuries were induced in shaved rats by 10 s immersion of the back surface in water at 90℃. Naringenin treatment (25, 50 and 100 mg/kg/day) was initiated 24 h following burn injury, and continued for 7 days. On treatment day 7, serum tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, nitric oxide (NO), prostaglandin (PG)E

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Burns; Caspase 3; Catalase; Dinoprostone; Flavanones; Gene Expression Regulation; Glutathione Peroxidase; Glutathione Transferase; Hot Temperature; Inflammation; Interleukin-1beta; Interleukin-6; Leukotriene B4; Male; NF-kappa B; Nitric Oxide; Oxidative Stress; Rats; Rats, Wistar; Skin; Superoxide Dismutase; Tumor Necrosis Factor-alpha; Wound Healing

Immune cells sense and react to a multitude of factors including both host and microbe-derived signals. Understanding how cells translate these cues into particular cellular behaviors is a complex yet critical area of study. We have previously shown that both neutrophils and macrophages are important for controlling the fish pathogen Streptococcus iniae. Here, we report both host and bacterial determinants leading to the formation of organized macrophage aggregates as part of the host inflammatory response in a subset of infected larvae. Streptococcal capsule was a required signal for aggregate formation. Macrophage aggregation coincided with NFκB activity, and the formation of these aggregates is mediated by leukotriene B4 (LTB4) produced by neutrophils. Depletion, inhibition, or genetic deletion of leukotriene A4 hydrolase (Lta4h), which catalyzes the last step in LTB4 synthesis, resulted in the absence of macrophage aggregation. Larvae with impaired neutrophil function also had impaired macrophage aggregation; however, aggregate formation was partially rescued with the addition of exogenous LTB4. Neutrophil-specific expression of lta4h was sufficient to rescue macrophage aggregation in Lta4h-deficient larvae and increased host survival following infection. In summary, our findings highlight a novel innate immune response to infection in which specific bacterial products drive neutrophils that modulate macrophage behavior through eicosanoid signaling.

Topics: Animals; Epoxide Hydrolases; Gene Deletion; Immunity, Innate; Inflammation; Leukotriene B4; Macrophages; Neutrophils; NF-kappa B; Streptococcal Infections; Streptococcus iniae; Zebrafish

Inflammatory preconditioning is a mechanism in which exposure to small doses of inflammatory stimuli prepares the body against future massive insult by activating endogenous protective responses. Phospholipase A2/5-lipoxygenase/leukotriene-B4 (PLA2/5-LOX/LTB4) axis is an important inflammatory signaling pathway. Naja sputatrix (Malayan spitting cobra) venom contains 15% secretory PLA2 of its dry weight. We investigated if Naja sputatrix venom preconditioning (VPC) reduces surgical brain injury (SBI)-induced neuroinflammation via activating PLA2/5-LOX/LTB4 cascade using a partial frontal lobe resection SBI rat model. Naja sputatrix venom sublethal dose was injected subcutaneously for 3 consecutive days prior to SBI. We observed that VPC reduced brain edema and improved neurological function 24 h and 72 h after SBI. The expression of pro-inflammatory mediators in peri-resection brain tissue was reduced with VPC. Administration of Manoalide, a PLA2 inhibitor or Zileuton, a 5-LOX inhibitor with VPC reversed the protective effects of VPC against neuroinflammation. The current VPC regime induced local skin inflammatory reaction limited to subcutaneous injection site and elicited no other toxic effects. Our findings suggest that VPC reduces neuroinflammation and improves outcomes after SBI by activating PLA2/5-LOX/LTB4 cascade. VPC may be beneficial to reduce post-operative neuroinflammatory complications after brain surgeries.

Topics: Animals; Arachidonate 5-Lipoxygenase; Biomarkers; Brain; Brain Edema; Brain Injuries; Elapid Venoms; Hydroxyurea; Inflammation; Intraoperative Complications; Leukocyte Count; Leukotriene B4; Lipoxygenase Inhibitors; Naja; Phospholipase A2 Inhibitors; Phospholipases A2; Rats; Signal Transduction; Skin; Subcutaneous Tissue; Terpenes

Topics: 5-Lipoxygenase-Activating Proteins; Acetates; Animals; Asthma; Cell Movement; Chemokines; Cyclopropanes; Epoxide Hydrolases; Humans; Inflammation; Leukotriene B4; Lipid Metabolism; Molecular Targeted Therapy; Neutrophil Activation; Neutrophils; Quinolines; Sulfides; T-Lymphocytes

Vascular changes, both endothelial and functional, are crucial events in inflammatory responses.. To investigate the dynamics of endothelial cell (EC) and functional changes during acute inflammation in an in vivo model of the skin using leukotriene B4.. EC proliferation, vascular network size, vessel diameter (VD), and hypoxia-inducible factor (HIF)-1α were studied by immunohistochemical CD31/Ki67 double staining and single staining of HIF-1α. Cutaneous perfusion (CP) was assessed using the Twente Optical Perfusion Camera.. The initial phase illustrated an increase in VD, Ki67+ EC, and HIF-1α expression and late-phase vascular expansion. The HIF-1α and Ki67+ EC expression was limited. CP and VD were augmented after 24 h.. The early phase of inflammation is characterized by EC proliferation and HIF-1α expression. Vascular expansion continues over time. CP and VD are seen in both phases of inflammation. Angiogenesis, vascular network formation, and perfusion are time-dependent processes which are mutually related during inflammation.

Topics: Administration, Cutaneous; Adult; Cell Proliferation; Endothelial Cells; Endothelium; Female; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Inflammation; Laser-Doppler Flowmetry; Leukotriene B4; Male; Middle Aged; Neovascularization, Physiologic; Parakeratosis; Skin; Young Adult

Recognizing patients at risk for pulmonary complications (PC) is of high clinical relevance. Migration of polymorphonuclear leukocytes (PMN) to inflammatory sites plays an important role in PC, and is tightly regulated by specific chemokines including interleukin (IL)-8 and other mediators such as leukotriene (LT)B4. Previously, we have reported that LTB4 indicated early patients at risk for PC after trauma. Here, the relevance of LTB4 to indicating lung integrity in a newly established long-term porcine severe trauma model (polytrauma, PT) was explored.. Twelve pigs (3 months old, 30 ± 5kg) underwent PT including standardized femur fracture, lung contusion, liver laceration, hemorrhagic shock, subsequent resuscitation and surgical fracture fixation. Six animals served as controls (sham). After 72h lung damage and inflammatory changes were assessed. LTB4 was determined in plasma before the experiment, immediately after trauma, and after 2, 4, 24 or 72h. Bronchoalveolar lavage (BAL)-fluid was collected prior and after the experiment.. Lung injury, local gene expression of IL-8, IL-1β, IL-10, IL-18 and PMN-infiltration into lungs increased significantly in PT compared with sham. Systemic LTB4 increased markedly in both groups 4h after trauma. Compared with declined plasma LTB4 levels in sham, LTB4 increased further in PT after 72h. Similar increase was observed in BAL-fluid after PT.. In a severe trauma model, sustained changes in terms of lung injury and inflammation are determined at day 3 post-trauma. Specifically, increased LTB4 in this porcine long-term model indicated a rapid inflammatory alteration both locally and systemically. The results support the concept of LTB4 as a biomarker for PC after severe trauma and lung contusion.

Topics: Animals; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Humans; Inflammation; Interleukins; Leukotriene B4; Lung; Lung Injury; Neutrophils; Swine; Wounds and Injuries

Leukotriene B

Topics: 5-Lipoxygenase-Activating Proteins; Achromobacter denitrificans; alpha-Defensins; Animals; Bacterial Load; Cells, Cultured; Dinoprostone; Gram-Negative Bacterial Infections; Inflammation; Leukotriene B4; Lung; Macrophages, Alveolar; Mice; Mice, 129 Strain; Mice, Knockout; Phagocytosis; Receptors, Leukotriene B4; Signal Transduction

1. Leukotriene B4 (LTB4) is a proinflammatory mediator important in the progression of a number of inflammatory diseases. Preclinical models can explore the role of LTB4 in pathophysiology using tool compounds, such as CP-105696, that modulate its activity. To support preclinical pharmacology studies, micro-sampling techniques and mathematical modeling were used to determine the pharmacokinetics of CP-105696 in mice within the context of systemic inflammation induced by a high-fat diet (HFD). 2. Following oral administration of doses > 35 mg/kg, CP-105696 kinetics can be described by a one-compartment model with first order absorption. The compound's half-life is 44-62 h with an apparent volume of distribution of 0.51-0.72 L/kg. Exposures in animals fed an HFD are within 2-fold of those fed a normal chow diet. Daily dosing at 100 mg/kg was not tolerated and resulted in a >20% weight loss in the mice. 3. CP-105696's long half-life has the potential to support a twice weekly dosing schedule. Given that most chronic inflammatory diseases will require long-term therapies, these results are useful in determining the optimal dosing schedules for preclinical studies using CP-105696.

Topics: Administration, Oral; Animals; Benzopyrans; Carboxylic Acids; Diet, High-Fat; Half-Life; Inflammation; Leukotriene B4; Mice; Models, Biological; Neutrophils

Trichomonas vaginalis is a sexually transmitted parasite that causes vaginitis in women and itself secretes lipid mediator leukotriene B

Topics: Cell Line; Cell Membrane; Exocytosis; Female; Humans; Inflammation; Leukotriene B4; Mast Cells; Membrane Glycoproteins; NADPH Oxidase 2; NADPH Oxidases; Protein Transport; Qb-SNARE Proteins; Qc-SNARE Proteins; Reactive Oxygen Species; Receptors, Leukotriene B4; RNA, Small Interfering; Signal Transduction; Trichomonas vaginalis; Trichomonas Vaginitis

Topics: Animals; Arachidonate 5-Lipoxygenase; Chromatography, Liquid; Disease Models, Animal; Eosinophils; Epidermolysis Bullosa Acquisita; Female; Inflammation; Leukotriene B4; Male; Mass Spectrometry; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Neutrophil Infiltration; Neutrophils; Pemphigoid, Bullous; Receptors, Leukotriene B4; Skin

Leukotriene B4 (LTB4)-mediated leukocyte recruitment and inflammatory cytokine production make crucial contributions to chronic inflammation and sepsis; however, the role of LTB4 in lipopolysaccharide (LPS)-induced cardiac dysfunction remains unclear. Therefore, the present study addressed this issue using an LTB4 receptor 1 (BLT1) inhibitor. Administration of LPS to mice resulted in decreased cardiovascular function. Inhibition of LTB4/BLT1 with the BLT1 inhibitor U75302 significantly improved survival and attenuated the LPS-induced acute cardiac dysfunction. During LPS challenge, the phosphorylated AMPK/ACC signaling pathway was slightly activated, and this effect was enhanced by U75302. Additionally, pNF-κB, Bax and cleaved caspase-3 were upregulated by LPS, and Bcl-2, IκB-α, mitochondrial complex I, complex II, and OPA1 were downregulated; however, these effects were reversed by U75302. The results indicated that the BLT1 antagonist suppressed cardiac apoptosis, inflammation, and mitochondrial impairment. Furthermore, the protection provided by the BLT1 inhibitor against LPS-induced cardiac dysfunction was significantly reversed by the AMPK inhibitor Compound C. In conclusion, inhibiting the LTB4/BLT1 signaling pathway via AMPK activation is a potential treatment strategy for septic cardiac dysfunction because it efficiently attenuates cardiac apoptosis, which may occur via the inhibition of inflammation and mitochondrial dysfunction.

Topics: Acetyl-CoA Carboxylase; AMP-Activated Protein Kinases; Animals; Anti-Inflammatory Agents; bcl-2-Associated X Protein; Cardiomyopathies; Cardiotonic Agents; Caspase 3; Fatty Alcohols; Gene Expression Regulation; Glycols; I-kappa B Proteins; Inflammation; Leukotriene B4; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Mitochondria; NF-kappa B; Oxazines; Proto-Oncogene Proteins c-bcl-2; Receptors, Leukotriene B4; Signal Transduction; Survival Analysis

The pro-inflammatory mediator leukotriene B

Topics: Amino Acid Motifs; Animals; Anti-Inflammatory Agents; beta-Alanine; Binding Sites; Bone Marrow Cells; Crystallography, X-Ray; Enzyme Inhibitors; Epoxide Hydrolases; Female; Gene Expression; Humans; Hydrolysis; Inflammation; Leukotriene B4; Mice; Mice, Inbred BALB C; Molecular Docking Simulation; Neutrophils; Oligopeptides; Proline; Protein Binding; Protein Interaction Domains and Motifs; Protein Structure, Secondary; Recombinant Proteins; Substrate Specificity

Chloroform extract (ALC) from the seeds of Phalaris canariensis were assayed for antiinflammatory activity by carrageenan-induced oedema, cotton pellets-induced granuloma, histamine-induced inflammation, croton oil-induced oedema, activity of myeloperoxidase (MPO), adjuvant-induced arthritis, quantification of TNFα, IL-1β, PGE2 and LTB4 and nitric oxide (NO) assay. ALC exhibited significant anti-inflammatory activity in different chemically-induced edemas in a dose dependent manner. In the chronic model cotton pellets-induced granuloma showed decreased formation of granuloma tissue. Also caused inhibition of ear inflammation edema and influx of polymorphonuclear cells, as evidence by a decrease in ear thickness and reduced myeloperoxidase activity and inhibit mediators of inflammation as TNFα, IL-1β, PGE2 and LTB4. When RAW 264.7 macrophages were treated with ALC together with LPS a significant inhibition of NO production was detected. These data provide evidence for antiinflammatory effect of P. canariensis by mechanisms that involve a reduced neutrophil influx and decreased production of inflammatory cytokines.

Topics: Animals; Anti-Inflammatory Agents; Carrageenan; Dinoprostone; Edema; Inflammation; Inflammation Mediators; Interleukin-1beta; Leukotriene B4; Macrophages; Male; Phalaris; Plant Extracts; Rats; Rats, Wistar; Seeds; Tumor Necrosis Factor-alpha

Infection of humans with Mycobacterium tuberculosis (Mtb) results in diverse outcomes that range from acute disease to establishment of persistence and to even clearance of the pathogen. These different outcomes represent the combined result of host heterogeneity on the one hand, and virulence properties of the infecting strain of pathogen on the other. From the standpoint of the host, the balance between PGE2, LXA4 and LTB4 represents at least one of the factors that dictates the eventual pathophysiology. We therefore built an ODE model to describe the host-pathogen interaction and studied the local stability properties of the system, to obtain the parametric conditions that lead to different disease outcomes. We then modulated levels of the pro- and anti-inflammatory lipid mediators to better understand the convergence between host phenotype and factors that relate to virulence properties of the pathogen. Global sensitivity analysis, using the variance-based method of extended Fourier Amplitude Sensitivity Test (eFAST), revealed that disease severity was indeed defined by combined effects of phenotypic variability at the level of both host and pathogen. Interestingly here, [PGE2] was found to act as a switch between bacterial clearance and acute disease. Our mathematical model suggests that development of more effective treatments for tuberculosis will be contingent upon a better understanding of how the intrinsic variability at the level of both host and pathogen contribute to influence the nature of interactions between these two entities.

Topics: Apoptosis; Computer Simulation; Dinoprostone; Humans; Inflammation; Leukotriene B4; Lipoxins; Macrophages; Models, Theoretical; Mycobacterium Infections; Mycobacterium tuberculosis; Necrosis; Phenotype; Treatment Outcome; Virulence

Airway inflammation in chronic obstructive pulmonary disease (COPD) is refractory to corticosteroids and hence COPD treatment is hindered and insufficient. This study assessed the effects of oral treatment with Montelukast (10 and 30 mg/kg) or dexamethasone (20 mg/kg) for 20 days on COPD model induced by chronic exposure to lipopolysaccharide (LPS). Six groups of male guinea pigs were studied. Group 1: naïve group, group 2: exposed to saline nebulization. Groups 3, 4, 5, and 6: exposed to 9 nebulizations of LPS (30 μg/ml) for 1 hour, 48 hours apart with or without treatment with Montelukast or dexamethasone. Airway hyperreactivity (AHR) to methacholine (MCh), histopathological study and bronchoalveolar lavage fluid (BALF) as well as lung tissue analyses were performed 48 hours after the final exposure to LPS (day 20). LPS-induced pulmonary dysfunction was associated with increased neutrophil count, leukotriene (LT) B4, and tumor necrosis factor (TNF)-α in BALF. Moreover, there was an increase in malondialdehyde (MDA) level and a decrease in histone deacetylases(HDAC) activity in the lung tissue. Both Montelukast (10 or 30 mg /kg) and dexamethasone significantly reduced neutrophil count in BALF and inflammatory cells in lung parenchyma as well as TNF-α, and MDA levels. However, dexamethasone was more effective (p < 0.05). Montelukast, at a dose of 30 mg /kg, significantly reduced specific airway resistance after the 9th LPS exposure, attenuated AHR to MCh, decreased LTB4 and increased HDAC activity in comparison to dexamethasone. These results suggest that treatment with Montelukast can be useful in chronic airway inflammatory diseases including COPD poorly responsive to glucocorticoids.

Topics: Acetates; Animals; Bronchoalveolar Lavage Fluid; Chronic Disease; Cyclopropanes; Dexamethasone; Disease Models, Animal; Glucocorticoids; Guinea Pigs; Histone Deacetylases; Inflammation; Leukocyte Count; Leukotriene Antagonists; Leukotriene B4; Lipopolysaccharides; Lung; Male; Malondialdehyde; Neutrophils; Pulmonary Disease, Chronic Obstructive; Quinolines; Respiratory Hypersensitivity; Sulfides; Tumor Necrosis Factor-alpha

Leukotrienes (LTs) are lipid mediators derived from arachidonic acid (AA) involved in a number of autoimmune/inflammatory disorders including asthma, allergic rhinitis and cardiovascular diseases. Salvinorin A (SA), a diterpene isolated from the hallucinogenic plant Salvia divinorum, is a well-established analgesic compound, but its anti-inflammatory properties are under-researched and its effects on LT production is unknown to date. Here, we studied the possible effect of SA on LT production and verified its actions on experimental models of inflammation in which LTs play a prominent role. Peritoneal macrophages (PM) stimulated by calcium ionophore A23187 were chosen as in vitro system to evaluate the effect of SA on LT production. Zymosan-induced peritonitis in mice and carrageenan-induced pleurisy in rats were selected as LT-related models to evaluate the effect of SA on inflammation as well as on LT biosynthesis. SA inhibited, in a concentration-dependent manner, A23187-induced LTB4 biosynthesis in isolated PM. In zymosan-induced peritonitis, SA inhibited cell infiltration, myeloperoxidase activity, vascular permeability and LTC4 production in the peritoneal cavity without decreasing the production of prostaglandin E2. In carrageenan-induced pleurisy in rats, a more sophisticated model of acute inflammation related to LTs, SA significantly inhibited LTB4 production in the inflammatory exudates, along with reducing the phlogistic process in the lung. In conclusion, SA inhibited LT production and it was effective in experimental models of inflammation in which LTs play a pivotal role. SA might be considered as a lead compound for the development of drugs useful in LTs-related diseases.

Topics: Animals; Anti-Inflammatory Agents; Arachidonic Acid; Diterpenes; Diterpenes, Clerodane; Hallucinogens; Inflammation; Leukotriene Antagonists; Leukotriene B4; Macrophages, Peritoneal; Mice; Models, Theoretical; Rats; Rats, Wistar; Zymosan

We employed our inhalation methodology to examine whether biomarkers of inflammation and oxidative stress would be produced in mice following inhalation of aerosols containing carbonaceous particles or the vapor of pesticides prevalent during the first Gulf War. Exposure to two putative Gulf War Illness toxins, fine airborne particles and the pesticide malathion, increased biomarkers of inflammation and oxidative stress in Friend virus B (FVB) female mice. Mice inhaling particles 24 h before had increased lung lavage and plasma Leukotriene B4 (LTB4) (a biomarker of inflammation) and PGF2α (a biomarker of oxidative stress) levels, lung lavage protein and lung lavage lactic dehydrogenase (LDH) levels. These changes were a function of particle density and exposure time. Compared to particle inhalation, mice inhaling malathion 24 h before had small increase in plasma LTB4 and PGF2α levels but no increase in lung lavage LTB4, lung lavage protein, lung lavage LDH, and lung lavage alveolar macrophage (AM) levels compared to unexposed control mice. AM from particle-exposed mice contained phagocytosed particles, while AM from malathion-exposed mice showed no abnormalities. Our results indicate that inhaling particles or malathion can alter inflammatory and oxidative biomarkers in mice and raise the possibility that these toxins may have altered inflammation and oxidative stress biomarkers in Gulf War-exposed individuals.

Topics: Administration, Inhalation; Aerosols; Animals; Biomarkers; Bronchoalveolar Lavage Fluid; Dinoprost; Environmental Exposure; Female; Gulf War; Inflammation; Leukotriene B4; Macrophages, Alveolar; Malathion; Mice; Mice, Inbred Strains; Oxidative Stress; Particle Size

The objective of this study was to evaluate how β-naphthoflavone interacts with lipopolysaccharide (LPS) and polyinosinic acid: polycytidylic acid (poly I: C) induced innate immune parameters as well as phase I and phase II detoxification enzymes in head kidney cells isolated from Atlantic cod. β-naphthoflavone is a pure agonist of aryl hydrocarbon receptor (AhR) while LPS and poly I: C are not. β-naphthoflavone was added to head kidney leukocytes alone or together with LPS or poly I: C and the responses were evaluated in terms of protein and gene expression. The results showed that β-naphthoflavone (25 nM), with and without LPS, significantly induced cytochrome P450 (cyp1c) transcription in cod head kidney cells. β-naphthoflavone (100 nM) in the presence of the virus mimic, poly I: C, also increased cyp1c1transcription. LPS induced cyp1c1, cyclooxygenase 2 (cox2), interleukin 1β (IL-1β), interleukin 6 (IL-6) and interleukin 8 (IL-8) transcription, genes that were not affected by the tested β-naphthoflavone concentrations alone. However, β-naphthoflavone (25 and 50 nM) strengthened LPS induced cox2 and IL-8 transcription. Cod head kidney cells exposed to β-naphthoflavone concentrations ranging from 25 to 100 nM, with and without LPS or poly I: C, expressed AhR protein. LPS or β-naphthoflavone (5-50 nM) significantly induced leukotriene B4 (LTB4) secretion compared to control. In conclusion, this study suggests that β-naphthoflavone could interfere with LPS induced immune cell signaling in cod head kidney cells.

Topics: Animals; beta-Naphthoflavone; Enzyme Inhibitors; Fish Proteins; Gadus morhua; Head Kidney; Immunity, Innate; Inflammation; Leukocytes; Leukotriene B4; Lipopolysaccharides; Metabolic Detoxication, Phase I; Metabolic Detoxication, Phase II; Poly I-C; Pseudomonas aeruginosa; Transcription, Genetic

This study tested the hypothesis that sickle red blood cell (SS-RBC) induce Toll-like receptors (TLR) and Nod-like receptor family, pyrin domain containing 3 (NLRP3)- inflammasome expression in peripheral blood mononuclear cells (PBMC). TLR and NLRP3 inflammasome could contribute to the maintenance of the inflammatory status in sickle cell anemia (SCA) patients, since SS-RBC act as danger signals activating these pathways. In this study, first, we evaluated TLR (2, 4, 5 and 9), NLRP3, Caspase-1, interleukin (IL)-1β and IL-18 expression in PBMC freshly isolated from SCA patients (SS-PBMC) in comparison with PBMC from healthy individuals (AA-PBMC). In the second moment, we investigated whether SS-RBC could interfere with the expression of these molecules in PBMC from healthy donor, in the absence or presence of hydroxyurea (HU) in vitro. TLRs and NLRP3 inflammasome expression were investigated by qPCR. IL-1β, Leukotriene-B4 (LTB4) and nitrite production were measured in PBMC (from healthy donor) culture supernatants. TLR2, TLR4, TLR5, NLRP3 and IL-1β were highly expressed in SS-PBMC when compared to AA-PBMC. Additionally, SS-RBC induced TLR9, NLRP3, Caspase-1, IL-1β and IL-18 expression and induced IL-1β, LTB4 and nitrite production in PBMC cultures. HU did not prevent TLR and NLRP3 inflammasome expression, but increased TLR2 and IL-18 expression and reduced nitrite production. In conclusion, our data suggest that TLR and inflammasome complexes may be key inducers of inflammation in SCA patients, probably through SS-RBC; also, HU does not prevent NLRP3 inflammasome- and TLR-dependent inflammation, indicating the need to develop new therapeutic strategies to SCA patients that act with different mechanisms of those observed for HU.

Topics: Adolescent; Anemia, Sickle Cell; Child; Child, Preschool; Erythrocytes, Abnormal; Female; Gene Expression Regulation; Humans; Inflammation; Interleukin-18; Interleukin-1beta; Leukocytes, Mononuclear; Leukotriene B4; Male; Nitrites; NLR Family, Pyrin Domain-Containing 3 Protein; Toll-Like Receptors

Evidence indicates an association between hypertension and chronic systemic inflammation in both human hypertension and experimental animal models. Previous studies in the spontaneously hypertensive rat (SHR) support a role for leukotriene B. Accumulating evidence indicates an association between hypertension and chronic systemic inflammation in both human hypertension and experimental animal models. Previous studies in the spontaneously hypertensive rat (SHR) support a role for leukotriene B

Topics: Animals; Arterial Pressure; Baroreflex; Benzopyrans; Carboxylic Acids; Hypertension; Inflammation; Leukotriene B4; Macrophages; Male; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptors, Leukotriene B4

We examined composition of plasma non-esterified fatty acids (NFAs), erythrocyte fatty acids, levels of eicosanoids in patients with asthma and chronic obstructive pulmonary disease (COPD) with different type of the inflammatory response. The results of our study show that asthma and COPD in remission are associated with changes in the composition NFAs of plasma, FA of erythrocytes, level eicosanoid despite the difference in the regulation of immunological mechanisms of systemic inflammation. These changes are characterized by excessive production of arachidonic acid (20:4n-6) and cyclooxygenase and lipoxygenase metabolites (thromboxane B2, leukotriene B4) and deficiency of their functional antagonist, eicosapentaenoic acid (20:5n-3). The recognized association between altered fatty acid composition and disorders of the immune mechanisms of regulation of systemic inflammation in COPD and asthma demonstrated the important role of fatty acids and their metabolites in persistence of inflammatory processes in diseases of the respiratory system in the condition of remission.. Izuchen sostav zhirnykh kislot (ZhK) plazmy krovi i membran éritrotsitov, uroven' éĭkozanoidov u bol'nykh bronkhial'noĭ astmoĭ (BA) i khronicheskoĭ obstruktivnoĭ bolezn'iu legkikh (KhOBL) pri raznom tipe vospalitel'noĭ reaktsii. Ustanovleno, chto techenie BA i KhOBL v period remissii, nesmotria na razlichie immunologicheskikh mekhanizmov reguliatsii sistemnogo vospaleniia, soprovozhdaetsia odnonapravlennymi izmeneniiami sostava neéterifitsirovannykh zhirnykh kislot plazmy krovi i ZhK membran éritrotsitov, urovnia éĭkozanoidov, kharakterizuiushchimisia povyshennoĭ produktsieĭ arakhidonovoĭ kisloty (20:4n-6) i ee tsiklooksigenaznykh i lipoksigenaznykh metabolitov (tromboksan V2, leĭkotrien V4) na fone defitsita funktsional'nogo antagonista – éĭkozapentaenovoĭ kisloty (20:5n-3). Obnaruzhennaia assotsiatsiia mezhdu modifikatsieĭ sostava zhirnykh kislot krovi i narusheniem immunnykh mekhanizmov reguliatsii sistemnogo vospaleniia pri KhOBL i BA svidetel'stvuet o vazhnom znachenii zhirnykh kislot i ikh metabolitov v persistentsii vospalitel'nogo protsessa pri zabolevaniiakh bronkholegochnoĭ sistemy v period remissii.

Topics: Adult; Arachidonic Acid; Asthma; Case-Control Studies; Eicosapentaenoic Acid; Female; Humans; Inflammation; Leukotriene B4; Lipoxygenases; Male; Prostaglandin-Endoperoxide Synthases; Pulmonary Disease, Chronic Obstructive; Thromboxane B2

Echinodorus macrophyllus (Kunth) Micheli (Alismataceae) is popularly used as an infusion to treat inflammatory diseases. This work fractionated the aqueous extract of E. macrophyllus (AEEm) to improve its anti-inflammatory effects.. Aqueous extract of E. macrophyllus was fractionated by Sephadex LH-20 and analysed by HPLC-DAD. Anti-inflammatory action was evaluated, in vivo, by air pouch model (total leucocyte, protein and leukotriene B. The fractionation of AEEm provided a more potent anti-inflammatory fraction containing flavonoids (Fr20) that reduces the migration of neutrophils and LTB4 release, probably contributing to its mechanism of action.

Topics: Alismataceae; Animals; Anti-Inflammatory Agents; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Flavonoids; Inflammation; Inflammation Mediators; Leukotriene B4; Macrophage-1 Antigen; Macrophages; Male; Mice; Neutrophil Infiltration; Neutrophils; Nitric Oxide; Phytotherapy; Plant Extracts; Plants, Medicinal; RAW 264.7 Cells; Solvents

Leukotriene B

Topics: Gene Expression Regulation; Humans; Inflammation; Leukocytes, Mononuclear; Leukotriene B4; Macrophages; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; NF-kappa B; Phosphorylation; Receptor for Advanced Glycation End Products; Receptors, Leukotriene B4

Rosmarinus officinalis L. phenolic compounds have attracted considerable attention because of their antioxidant and antimicrobial properties, including its ability to treat inflammatory disorders. In this work, we investigated the in vivo and in vitro effects of R. officinalis aqueous extract on neutrophil trafficking from the blood into an inflamed tissue, on cell-derived secretion of chemical mediators, and on oxidative stress. Anti-inflammatory activity was investigated using carrageenan-induced inflammation in the subcutaneous tissue of male Wistar rats orally treated with the R. officinalis extract (100, 200, or 400 mg/kg). The leukocyte influx (optical microscopy), secretion of chemical mediators (prostaglandin E2 (PGE2), TNF-α, interleukin 6 (IL-6), leukotriene B4 (LTB4), and cytokine-induced neutrophil chemoattractant 1 by enzyme-linked immunosorbent assay), and the anti-oxidative profile (super oxide dismutase (SOD), glutathione peroxidase, and thiobarbituric acid reactive substance (TBARS) spectrophotometry) were quantified in the inflamed exudate. N-Formyl-methionine-leucine-phenylalanine-induced chemotaxis, lipopolysaccharide-induced NO2 (-) production (Greiss reaction), and adhesion molecule expression (flow cytometry) were in vitro quantified using oyster glycogen recruited peritoneal neutrophils previous treated with the extract (1, 10, or 100 µg/mL). Animals orally treated with phosphate-buffered saline and neutrophils incubated with Hank's balanced salt solution were used as control. R. officinalis extract oral treatment caused a dose-dependent reduction in the neutrophil migration as well as decreased SOD, TBARS, LTB4, PGE2, IL-6, and TNF-α levels in the inflamed exudate. In vitro treatment with R. officinalis decreased neutrophil chemotaxis, NO2 (-) production, and shedding of L-selectin and β2 integrin expressions. Results here presented show that R. officinalis aqueous extract displays important in vivo and in vitro anti-inflammatory actions by blocking pathways of neutrophil migration and secretion, suggesting its therapeutic application to acute inflammatory reactions.

Topics: Animals; Anti-Inflammatory Agents; CD18 Antigens; Cell Adhesion Molecules; Chemotaxis, Leukocyte; Cytokines; Dinoprostone; Inflammation; Interleukin-6; L-Selectin; Leukotriene B4; Lipopolysaccharides; Male; Neutrophils; Plant Extracts; Rats; Rats, Wistar; Rosmarinus; Tumor Necrosis Factor-alpha

The role of exhaled H2S as a marker of airway inflammation and its relationship with COPD severity remain to be determined.. Airway inflammation was classified in 77 COPD subjects based on the presence of inflammatory cells in induced sputum. We investigated the association between disease phenotype and exhaled H2S, lung function, and plasma levels of several inflammatory factors, including tumor necrosis factor alpha, interleukin-8, and leukotriene B4.. In total, 33.77% of enrolled COPD subjects were diagnosed with eosinophilia. These subjects had a longer disease course, smoked fewer cigarettes, and experienced more frequent exacerbation events before study enrollment. However, they also had worse lung function and larger residual volume, they demonstrated greater changes in FEV1 following bronchodilator inhalation. Although levels of plasma inflammatory factors did not significantly differ between subjects with and without eosinophilia, subjects without eosinophilia had significantly higher levels of exhaled H2S (9.19±2.74 vs 7.24±1.68 parts per billion, P=.01). Furthermore, exhaled H2S levels were negatively correlated with induced sputum eosinophils (r=-0.45, P=.05), and positively correlated with inspiratory capacity in COPD subjects (r=0.51, P=.026), but did not correlate significantly with plasma inflammatory factors. A cut-off value of 7.10 parts per billion of exhaled H2S predicted a non-eosinophilic phenotype with 68.6% sensitivity and 77.9% specificity.. Exhaled levels of H2S were lower in subjects with eosinophilia. Increased levels of exhaled H2S predicted a non-eosinophilic phenotype in our study population.

Topics: Aged; Area Under Curve; Biomarkers; Breath Tests; Eosinophilia; Eosinophils; Exhalation; Female; Forced Expiratory Volume; Humans; Hydrogen Sulfide; Inflammation; Inspiratory Capacity; Interleukin-8; Leukotriene B4; Male; Middle Aged; Phenotype; Predictive Value of Tests; Pulmonary Disease, Chronic Obstructive; Residual Volume; ROC Curve; Sputum; Tumor Necrosis Factor-alpha

Some studies suggest that 5-lipoxygenase (5-LOX) inhibition or leukotriene receptor antagonism may effectively attenuate different kinds of pain. In the present study, we investigated whether esculetin (which, among other actions, potently inhibits 5-LOX) possesses analgesic activity in acute non-inflammatory pain and acute inflammatory pain models in rats. We also examined the effects of zileuton, a selective 5-LOX inhibitor, on esculetin activity. Plasma concentrations of leukotriene B4 (LTB4 ) after administration of esculetin were also determined. Esculetin (1.25-20 mg/kg, i.p.) dose-dependently alleviated hyperalgesia and exhibited antinociceptive effects in both experimental models. The greatest effect of esculetin was observed with a dose of 20 mg/kg. In carrageenan-induced inflammatory pain in rats, 20 mg/kg esculetin reversed or mitigated hyperalgesia, increasing the threshold to mechanical stimuli from a control value of -23.8 ± 1.8% to 15.2 ± 2.2% (P < 0.01) and that to thermal stimuli from -52.5 ± 6.1% to -9.5 ± 3.9% (P < 0.01). In non-inflammatory pain, after esculetin (20 mg/kg) administration the threshold values to mechanical and thermal stimuli increased to 75.9 ± 4.2% and 59.2 ± 4.3%, respectively (P < 0.01 for both). Zileuton (30 mg/kg, p.o.) alone slightly but significantly increased the pain threshold in the non-inflammatory and inflammatory acute pain models. Pretreatment with 30 mg/kg, p.o., zileuton significantly enhanced the analgesic activity of 5 mg/kg, i.p., esculetin in both pain models. Moreover, esculetin (10 mg/kg, i.p.) decreased LTB4 concentrations in the blood from 244 ± 29 pg/mL in the control group to 185 ± 11 pg/mL (P < 0.005). The results of the present study suggest the involvement of the 5-LOX pathway in esculetin analgesia.

Topics: Analgesia; Analgesics; Animals; Arachidonate 5-Lipoxygenase; Disease Models, Animal; Hydroxyurea; Hyperalgesia; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pain; Pain Threshold; Rats; Umbelliferones

Leukotriene B4 (LTB4) is a potent inflammatory mediator derived from arachidonic acid. Two G protein-coupled receptors for LTB4 have been identified: a high-affinity receptor, BLT1, and a low-affinity receptor, BLT2. Both receptors mainly couple to pertussis toxin-sensitive Gi-like G proteins and induce cell migration. 12(S)-hydroxy-5Z,8E,10E-heptadecatrienoic acid (12-HHT) was identified to bind BLT2 with higher affinity than LTB4. Expression of BLT1 was confirmed in type 1 helper T cells, type 2 helper T cells, type 17 helper T cells, effector CD8(+) T cells, dendritic cells and osteoclasts in addition to granulocytes, eosinophils and macrophages, and BLT1-deficient mice showed greatly reduced phenotypes in models of various inflammatory diseases, such as peritonitis, bronchial asthma, rheumatoid arthritis, atherosclerosis and osteoporosis. In mice, BLT2 expression is restricted to intestinal epithelial cells and epidermal keratinocytes. BLT2-deficient mice showed enhanced colitis after administration of dextran sulfate, possibly due to reduced intestinal barrier function. An aspirin-dependent reduction in 12-HHT production was responsible for delayed skin wound healing, showing that the 12-HHT/BLT2 axis also plays an important role in skin biology. BLT1 and BLT2 are therefore potential targets for the development of novel drugs.

Topics: Animals; Aspirin; CD8-Positive T-Lymphocytes; Cell Movement; Cloning, Molecular; Humans; Immunity, Innate; Inflammation; Leukotriene B4; Mice; Receptors, Leukotriene B4; Wound Healing

Inflammatory processes in the asthmatic lung involve the large and small airway and alveolar sites. Leukotriene B4 (LTB₄) is an important disease marker, but its role in inflammation of the small airways in asthma has not been established yet.. To distinguish between large and small airway or alveolar LTB₄ concentrations in children with asthma using the new technique of fractionated exhaled breath condensate sampling.. Sixty-eight children (9-17 years old, 33 children with asthma and 35 controls) underwent fractional exhaled nitric oxide (FeNO) measurements, lung function testing, and collection of fractionated exhaled breath condensate using a capnograph-based approach. The LTB₄ concentrations in the small airway or alveolar and large airway fractions were correlated to disease status, lung function impairment, and clinical parameters.. Children with asthma had significantly higher LTB₄ concentrations in the small airway or alveolar fraction than controls (5.58 pg/mL; 95% interquartile range [IQR], 2.0-11.77 pg/mL; vs 2.0 pg/mL; 95% IQR, 2.0-6.2 pg/mL; P = .003). No difference was found between the groups in the large airway fraction. Children with obstructive lung function impairment (forced expiratory volume in 1 second z score <-1.65) had increased small airway or alveolar LTB₄ concentrations compared with children without impairment (2.0 pg/mL; 95% IQR, 2.0-9.21 pg/mL; vs 18.32 pg/mL; 95% IQR, 3.7-23.02 pg/mL; P = .04). Children with asthma but without pathologic obstructive lung function still had higher LTB₄ concentrations than controls (5.57 pg/mL; 95% IQR, 2.00-10.60 pg/mL; vs 2.00 pg/mL; 95% IQR, 2.00-6.20 pg/mL; P = .01).. LTB₄ is detectable and elevated in the small airway or alveolar fraction of exhaled breath condensate in pediatric asthma. Because of the possibility of detecting elevated levels in patients without lung function impairment in controlled disease, it may be used as a noninvasive marker of small airways disease; however, future long-term studies are needed.

Topics: Adolescent; Asthma; Breath Tests; Child; Exhalation; Female; Forced Expiratory Volume; Humans; Inflammation; Leukotriene B4; Male; Nitric Oxide

Type 1 diabetes mellitus (T1DM) is associated with chronic systemic inflammation and enhanced susceptibility to systemic bacterial infection (sepsis). We hypothesized that low insulin concentrations in T1DM trigger the enzyme 5-lipoxygenase (5-LO) to produce the lipid mediator leukotriene B4 (LTB4), which triggers systemic inflammation that may increase susceptibility to polymicrobial sepsis. Consistent with chronic inflammation, peritoneal macrophages from two mouse models of T1DM had greater abundance of the adaptor MyD88 (myeloid differentiation factor 88) and its direct transcriptional effector STAT-1 (signal transducer and activator of transcription 1) than macrophages from nondiabetic mice. Expression of Alox5, which encodes 5-LO, and the concentration of the proinflammatory cytokine interleukin-1β (IL-1β) were also increased in peritoneal macrophages and serum from T1DM mice. Insulin treatment reduced LTB4 concentrations in the circulation and Myd88 and Stat1 expression in the macrophages from T1DM mice. T1DM mice treated with a 5-LO inhibitor had reduced Myd88 mRNA in macrophages and increased abundance of IL-1 receptor antagonist and reduced production of IL-β in the circulation. T1DM mice lacking 5-LO or the receptor for LTB4 also produced less proinflammatory cytokines. Compared to wild-type or untreated diabetic mice, T1DM mice lacking the receptor for LTB4 or treated with a 5-LO inhibitor survived polymicrobial sepsis, had reduced production of proinflammatory cytokines, and had decreased bacterial counts. These results uncover a role for LTB4 in promoting sterile inflammation in diabetes and the enhanced susceptibility to sepsis in T1DM.

Topics: Analysis of Variance; Animals; Arachidonate 5-Lipoxygenase; Chromatin Immunoprecipitation; Cytokines; Diabetes Mellitus, Type 1; Female; Gene Expression Regulation; Immunoblotting; Inflammation; Inflammation Mediators; Insulin; Leukotriene B4; Macrophages; Mice; Mice, Knockout; Myeloid Differentiation Factor 88; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Sepsis; STAT1 Transcription Factor

Insulin resistance results from several pathophysiologic mechanisms, including chronic tissue inflammation and defective insulin signaling. We found that liver, muscle and adipose tissue exhibit higher levels of the chemotactic eicosanoid LTB4 in obese high-fat diet (HFD)-fed mice. Inhibition of the LTB4 receptor Ltb4r1, through either genetic or pharmacologic loss of function, led to an anti-inflammatory phenotype with protection from insulin resistance and hepatic steatosis. In vitro treatment with LTB4 directly enhanced macrophage chemotaxis, stimulated inflammatory pathways, reduced insulin-stimulated glucose uptake in L6 myocytes, and impaired insulin-mediated suppression of hepatic glucose output in primary mouse hepatocytes. This was accompanied by lower insulin-stimulated Akt phosphorylation and higher Irs-1/2 serine phosphorylation, and all of these events were dependent on Gαi and Jnk1, two downstream mediators of Ltb4r1 signaling. These observations elucidate a novel role of the LTB4-Ltb4r1 signaling pathway in hepatocyte and myocyte insulin resistance, and they show that in vivo inhibition of Ltb4r1 leads to robust insulin-sensitizing effects.

Topics: Animals; Blood Glucose; Diet, High-Fat; Fatty Liver; Hepatocytes; Inflammation; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Leukotriene B4; Macrophages; Mice; Mice, Obese; Muscle Fibers, Skeletal; Obesity; Phosphorylation; Proto-Oncogene Proteins c-akt; Receptors, Leukotriene B4; Signal Transduction

To observe the effects of docosahexaenoic acid (DHA) on the expressions of TNF-α, IL-6, and leukotriene B4 (LTB4) in serum and expression of NF-κB in pulmonary tissue of rats with severe scald injury.. One hundred and sixty SD rats were divided into sham injury (A), sham injury+DHA (B), scald (C), and scald+DHA (D) groups according to the random number table, with 40 rats in each group. Rats in groups A and B were sham injured, while rats in groups C and D were inflicted with 30% TBSA full-thickness scald on the back. Rats in groups B and D were injected with 0.5 mg/mL DHA solution with the dosage of 1 mL/kg via tail vein 5 minutes post injury, while rats in groups A and C with normal saline solution 1 mL/kg. At post injury hour (PIH) 3, 6, 12, 24, and 48, pulmonary tissue and abdominal aorta blood were collected from 8 rats in each group. The serum levels of TNF-α, IL-6, and LTB4 were determined with ELISA, and the protein expression of NF-κB p65 in pulmonary tissue was determined with Western blotting. Data were processed with analysis of variance of factorial design and LSD-t test.. (1) The serum levels of TNF-α and IL-6 of rats in group A were similar to those of group B at each time point (with tTNF-α values from 0.223 to 0.947, tIL-6 values from 0.767 to 2.084, P values above 0.05). Compared with those of group A, the serum levels of TNF-α and IL-6 of rats in groups C and D were significantly higher at each time point (with tTNF-α values from 11.800 to 40.357, tIL-6 values from 10.334 to 39.321, P values below 0.01). The serum levels of TNF-α and IL-6 of rats in group D were significantly lower than those of group C at each time point (with tTNF-α values from -17.643 to -8.331, tIL-6 values from -21.596 to -6.332, P values below 0.01). The serum levels of TNF-α and IL-6 in groups C and D both showed a trend of increase earlier and decrease later, and they peaked at PIH 12, respectively (360.4 ± 13.2), (306.8 ± 7.2) pg/mL and (265.4 ± 12.3), (230.5 ± 2.2) pg/mL. (2) The serum level of LTB4 in group A was similar to that of group B at each time point (with t values from 0.787 to 1.096, P values above 0.05). The serum level of LTB4 was significantly higher in groups C and D than in group A at each time point (with t values from 7.501 to 38.962, P values below 0.01). The serum level of LTB4 in group D was obviously lower than that of group C at each time point (with t values from -19.244 to -2.532, P values below 0.01). The serum level of LTB4 in groups C and D both showed a trend of increase earlier and decrease later, and it peaked at PIH 12, (4.59 ± 0.29) and (2.85 ± 0.32) ng/mL respectively. (3) The protein expression of NF-κB p65 in pulmonary tissue in group A was similar to that of group B at each time point (with t values from 0.847 to 1.256, P values above 0.05). The protein expression of NF-κB p65 was significantly higher in groups C and D than in group A at each time point (with t values from 15.167 to 98.074, P values below 0.01). The protein expression of NF-κB p65 in group D was obviously lower than that of group C at each time point (with t values from -37.190 to -14.415, P values below 0.01). The protein expression of NF-κB p65 in groups C and D both showed a trend of increase earlier and decrease later, and it peaked at PIH 12, respectively 4.46 ± 0.12 and 2.94 ± 0.21.. Parenteral supply of DHA to rats with severe scald injury can reduce the levels of TNF-α, IL-6, and LTB4 in serum and decrease the expression of NF-κB in pulmonary tissue, thus alleviating the inflammation response.

Topics: Animals; Blotting, Western; Burns; Cytokines; Docosahexaenoic Acids; Enzyme-Linked Immunosorbent Assay; Inflammation; Interleukin-6; Leukotriene B4; Lung; NF-kappa B; Rats; Rats, Sprague-Dawley; Serum; Soft Tissue Injuries; Tumor Necrosis Factor-alpha; Up-Regulation

Chronic exposure to crystalline silica (CS) causes silicosis, an irreversible lung inflammatory disease that may eventually lead to lung cancer. In this study, we demonstrate that in K-ras(LA1) mice, CS exposure markedly enhances the lung tumour burden and genetic deletion of leukotriene B4 receptor-1 (BLT1(-/-)) attenuates this increase. Pulmonary neutrophilic inflammation induced by CS is significantly reduced in BLT1(-/-)K-ras(LA1) mice. CS exposure induces LTB4 production by mast cells and macrophages independent of inflammasome activation. In an air-pouch model, CS-induced neutrophil recruitment is dependent on LTB4 production by mast cells and BLT1 expression on neutrophils. In an implantable lung tumour model, CS exposure results in rapid tumour growth and decreased survival that is attenuated in the absence of BLT1. These results suggest that the LTB4/BLT1 axis sets the pace of CS-induced sterile inflammation that promotes lung cancer progression. This knowledge may facilitate development of immunotherapeutic strategies to fight silicosis and lung cancer.

Topics: Animals; Cell Proliferation; Chemokines; Chemotactic Factors; Crystallization; Disease Progression; Inflammation; Inflammation Mediators; Interleukin-1beta; Leukotriene B4; Lung Neoplasms; Mice, Inbred C57BL; Mice, Transgenic; Models, Biological; Neutrophil Infiltration; Proto-Oncogene Proteins p21(ras); Receptors, Leukotriene B4; Silicon Dioxide

Leukotriene B4 (LTB4 ) is a lipid mediator that is rapidly generated in inflammatory sites, and its functional receptor, BLT1, is mostly expressed on immune cells. Contact dermatitis is a common inflammatory skin disease characterized by skin oedema and abundant inflammatory infiltrates, primarily including neutrophils and CD8(+) T cells. The role of the LTB4 -BLT1 axis in contact dermatitis remains largely unknown. In this study, we found up-regulated gene expression of 5-lipoxygenase and leukotriene A4 hydrolase, two critical enzymes for LTB4 synthesis, BLT1 and elevated LTB4 levels in skin lesions of oxazolone (OXA)-induced contact dermatitis. BLT1 deficiency or blockade of LTB4 and BLT1 by the antagonists, bestatin and U-75302, respectively, in the elicitation phase caused significant decreases in ear swelling and skin-infiltrating neutrophils and CD8(+) T cells, which was accompanied by significantly reduced skin expression of CXCL1, CXCL2, interferon-γ and interleukin-1β. Furthermore, neutrophil depletion during the elicitation phase of OXA-induced contact dermatitis also caused significant decreases in ear swelling and CD8(+) T-cell infiltration accompanied by significantly decreased LTB4 synthesis and gene expression of CXCL2, interferon-γ and interleukin-1β. Importantly, subcutaneous injection of exogenous LTB4 restored the skin infiltration of CD8(+) T cells in neutrophil-depleted mice following OXA challenge. Collectively, our results demonstrate that the LTB4 -BLT1 axis contributes to OXA-induced contact dermatitis by mediating skin recruitment of neutrophils, which are a major source of LTB4 that sequentially direct CD8(+) T-cell homing to OXA-challenged skin. Hence, LTB4 and BLT1 could be potential therapeutic targets for the treatment of contact dermatitis.

Topics: Animals; Arachidonate 5-Lipoxygenase; CD8-Positive T-Lymphocytes; Chemokine CXCL1; Chemokine CXCL2; Dermatitis, Contact; Epoxide Hydrolases; Fatty Alcohols; Female; Glycols; Inflammation; Interferon-gamma; Interleukin-1beta; Leucine; Leukotriene B4; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Oxazolone; Receptors, Leukotriene B4; Skin

Allergic diseases, such as asthma and allergic rhinitis, are common. Therefore, the discovery of therapeutic drugs for these conditions is essential. Methyleugenol (ME) is a natural compound with antiallergic, antianaphylactic, antinociceptive, and anti-inflammatory effects. This study examined the antiallergic effect of ME on IgE-mediated inflammatory responses and its antiallergy mechanism in the mast cell line, RBL-2H3. We found that ME significantly inhibited the release of β-hexosaminidase, tumor necrosis factor- (TNF-) α, and interleukin- (IL-) 4, and was not cytotoxic at the tested concentrations (0-100 μM). Additionally, ME markedly reduced the production of the proinflammatory lipid mediators prostaglandin E2 (PGE2), prostaglandin D2 (PGD2), leukotriene B4 (LTB4), and leukotriene C4 (LTC4). We further evaluated the effect of ME on the early stages of the FcεRI cascade. ME significantly inhibited Syk phosphorylation and expression but had no effect on Lyn. Furthermore, it suppressed ERK1/2, p38, and JNK phosphorylation, which is implicated in proinflammatory cytokine expression. ME also decreased cytosolic phospholipase A2 (cPLA2) and 5-lipoxygenase (5-LO) phosphorylation and cyclooxygenase-2 (COX-2) expression. These results suggest that ME inhibits allergic response by suppressing the activation of Syk, ERK1/2, p38, JNK, cPLA2, and 5-LO. Furthermore, the strong inhibition of COX-2 expression may also contribute to the antiallergic action of ME. Our study provides further information about the biological functions of ME.

Topics: Animals; Arachidonic Acid; beta-N-Acetylhexosaminidases; Cell Line, Tumor; Cell Respiration; Dinoprostone; Eugenol; Extracellular Signal-Regulated MAP Kinases; Hypersensitivity; Immunoenzyme Techniques; Immunoglobulin E; Inflammation; Interleukin-4; Leukotriene B4; Leukotriene C4; Mast Cells; Mutagens; Prostaglandin D2; Rats; Tumor Necrosis Factor-alpha

In addition to lung volume restriction, individuals with chronic tetraplegia exhibit reduced airway caliber and bronchodilator responsiveness similar to persons with asthma. In asthma, airflow obstruction is closely linked to airway inflammation. Conversely, little is known regarding the airway inflammatory response in tetraplegia. To compare levels of biomarkers of inflammation in exhaled breath condensate (EBC) and serum in subjects with chronic tetraplegia, mild asthma, and able-bodied controls.Prospective, observational pilot study. Thirty-four subjects participated: tetraplegia (n = 12), asthma (n = 12), controls (n = 10). Biomarkers in EBC [8-isoprostane (8-IP), leukotriene B4 (LT-B4), prostaglandin E2 (PG-E2), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6)] and serum (8-IP, LT-B4, TNF-α, IL-6) were determined using commercially available EIA kits (Cayman Chemical Company, Ann Arbor, MI). Separate, one-way ANOVA with Bonferroni's post-hoc analyses were performed to determine group differences in demographic and dependent variables [EBC and serum biomarkers, fractional exhaled nitric oxide (FeNO), pulmonary function parameters, and specific airway conductance (sGaw)]. The tetraplegia group had significantly elevated 8-IP levels in EBC compared to the asthma (68 ± 38 versus 21 ± 13 pg ml(-1); p < 0.001) and control groups (22 ± 13 pg ml(-1); p < 0.01), respectively. FeNO levels were significantly elevated in the asthma compared to the control group (26 ± 18 versus 11 ± 4 ppb; p < 0.05), and trended higher than levels in the tetraplegia group (15 ± 6; p = 0.08). Levels of serum biomarkers did not differ significantly among groups. Through analysis of EBC, levels of 8-IP were significantly elevated compared to levels found in individuals with mild asthma and healthy controls. Further studies are needed to extend upon these preliminary findings that suggest the presence of airway inflammation in subjects with chronic tetraplegia, and how this relates to pulmonary dysfunction in this population.

Topics: Asthma; Biomarkers; Breath Tests; Case-Control Studies; Dinoprost; Exhalation; Female; Humans; Inflammation; Interleukin-6; Leukotriene B4; Male; Middle Aged; Nitric Oxide; Pilot Projects; Prospective Studies; Quadriplegia; Tumor Necrosis Factor-alpha

Cytochrome P-450 epoxygenase (EPOX)-derived epoxyeicosatrienoic acids (EETs), 5-lipoxygenase (5-LO), and leukotriene B4 (LTB4), the product of 5-LO, all play a pivotal role in the vascular inflammatory process. We have previously shown that EETs can alleviate oxidized low-density lipoprotein (ox-LDL)-induced endothelial inflammation in primary rat pulmonary artery endothelial cells (RPAECs). Here, we investigated whether ox-LDL can promote LTB4 production through the 5-LO pathway. We further explored how exogenous EETs influence ox-LDL-induced LTB4 production and activity. We found that treatment with ox-LDL increased the production of LTB4 and further led to the expression and release of both monocyte chemoattractant protein-1 (MCP-1/CCL2) and intercellular adhesion molecule-1 (ICAM-1). All of the above ox-LDL-induced changes were attenuated by the presence of 11,12-EET and 14,15-EET, as these molecules inhibited the 5-LO pathway. Furthermore, the LTB4 receptor 1 (BLT1 receptor) antagonist U75302 attenuated ox-LDL-induced ICAM-1 and MCP-1/CCL2 expression and production, whereas LY255283, a LTB4 receptor 2 (BLT2 receptor) antagonist, produced no such effects. Moreover, in RPAECs, we demonstrated that the increased expression of 5-LO and BLT1 following ox-LDL treatment resulted from the activation of nuclear factor-κB (NF-κB) via the p38 mitogen-activated protein kinase (MAPK) pathway. Our results indicated that EETs suppress ox-LDL-induced LTB4 production and subsequent inflammatory responses by downregulating the 5-LO/BLT1 receptor pathway, in which p38 MAPK phosphorylation activates NF-κB. These results suggest that the metabolism of arachidonic acid via the 5-LO and EPOX pathways may present a mutual constraint on the physiological regulation of vascular endothelial cells.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonate 5-Lipoxygenase; Blotting, Western; Cells, Cultured; Inflammation; Leukotriene B4; Lipoproteins, LDL; Male; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Pulmonary Artery; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Receptors, Leukotriene B4; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Vasodilator Agents

The aim of this study was to investigate the effects of the administration of oral arachidonic acid (AA) in rats with or without dextran sulphate sodium (DSS)-induced inflammatory bowel disease. Male Wistar rats were administered AA at 0, 5, 35 or 240 mg/kg daily by gavage for 8 weeks. Inflammatory bowel disease was induced by replacing drinking water with 3 % DSS solution during the last 7 d of the AA dosing period. These animals passed loose stools, diarrhoea and red-stained faeces. Cyclo-oxygenase-2 concentration and myeloperoxidase activity in the colonic tissue were significantly increased in the animals given AA at 240 mg/kg compared with the animals given AA at 0 mg/kg. Thromboxane B2 concentration in the medium of cultured colonic mucosae isolated from these groups was found to be dose-dependently increased by AA, and the increase was significant at 35 and 240 mg/kg. Leukotriene B4 concentration was also significantly increased and saturated at 5 mg/kg. In addition, AA at 240 mg/kg promoted DSS-induced colonic mucosal oedema with macrophage infiltration. In contrast, administration of AA for 8 weeks, even at 240 mg/kg, showed no effects on the normal rats. These results suggest that in rats with bowel disease AA metabolism is affected by oral AA, even at 5 mg/kg per d, and that excessive AA may aggravate inflammation, whereas AA shows no effects in rats without inflammatory bowel disease.

Topics: Animals; Arachidonic Acid; Colitis; Colon; Cyclooxygenase 2; Dextran Sulfate; Diet; Inflammation; Inflammatory Bowel Diseases; Intestinal Mucosa; Leukotriene B4; Macrophages; Male; Peroxidase; Rats, Wistar; Thromboxane B2

Excessive or unresolved inflammation leads to tissue lesions. Adipose tissue-derived mesenchymal stromal cells (AMSCs) have shown protective effects that may be dependent on the modulation of inflammation by secreted factors.. We used the zymosan-induced mouse air pouch model at two time points (4 h and 18 h) to evaluate the in vivo effects of AMSCs and their conditioned medium (CM) on key steps of the early inflammatory response. We assessed the effects of AMSCs and CM on leukocyte migration and myeloperoxidase activity. The levels of chemokines, cytokines and eicosanoids in exudates were measured by use of enzyme-linked immunoassay or radio-immunoassay. In addition, the expression of cyclooxygenase-2 and microsomal prostaglandin E synthase-1 (mPGES-1) was studied by use of Western blotting and the phosphorylation of p65 nuclear factor-κB (NF-κB) by immunofluorescence.. All inflammatory parameters were significantly reduced by CM and AMSCs to a similar extent at 4 h after zymosan injection with lower effects at 18 h. The observed inhibition of leukocyte migration was associated with reduced levels of chemokines and leukotriene B4. Interleukin-1β, interleukin-6, tumor necrosis factor-α and tumor necrosis factor-stimulated gene 6 levels were significantly decreased. The downregulation of mPGES-1 was associated with inhibition of prostaglandin E2 production. Our results suggest that these anti-inflammatory effects are related, in part, to the inhibition of NF-κB activation.. AMSCs dampen the early process of inflammation in the zymosan-induced mouse air pouch model through paracrine mechanisms. These results support the potential utility of these cells as a source of novel treatment approaches for inflammatory pathologies.

Topics: Adipose Tissue; Animals; Cell Movement; Culture Media, Conditioned; Cyclooxygenase 2; Cytokines; Dinoprostone; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Inflammation; Interleukin-1beta; Interleukin-6; Intramolecular Oxidoreductases; Leukocytes; Leukotriene B4; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Paracrine Communication; Prostaglandin-E Synthases; Transcription Factor RelA; Tumor Necrosis Factor-alpha; Zymosan

Bioactive matrix fragments (matrikines) have been identified in a myriad of disorders, but their impact on the evolution of airway inflammation has not been demonstrated. We recently described a pathway where the matrikine and neutrophil chemoattractant proline-glycine-proline (PGP) could be degraded by the enzyme leukotriene A4 hydrolase (LTA4H). LTA4H classically functions in the generation of pro-inflammatory leukotriene B4, thus LTA4H exhibits opposing pro- and anti-inflammatory activities. The physiological significance of this secondary anti-inflammatory activity remains unknown. Here we show, using readily resolving pulmonary inflammation models, that loss of this secondary activity leads to more pronounced and sustained inflammation and illness owing to PGP accumulation. PGP elicits an exacerbated neutrophilic inflammation and protease imbalance that further degrades the extracellular matrix, generating fragments that perpetuate inflammation. This highlights a critical role for the secondary anti-inflammatory activity of LTA4H and thus has consequences for the generation of global LTA4H inhibitors currently being developed.

Topics: Animals; Epoxide Hydrolases; Extracellular Matrix; Flow Cytometry; Haemophilus Infections; Haemophilus influenzae type b; Inflammation; Leukocyte Elastase; Leukotriene B4; Lung; Macrophages, Alveolar; Matrix Metalloproteinase 12; Matrix Metalloproteinase 9; Mice; Mice, Knockout; Neutrophils; Oligopeptides; Pneumonia, Bacterial; Pneumonia, Pneumococcal; Proline; Receptors, Leukotriene B4; Streptococcus pneumoniae

Leukotriene B4 (LTB4), a central mediator of inflammation, is well known for its chemoattractant properties on effectors cells of the immune system. LTB4 also has the ability to control microbial infection by improving host innate defenses through the release of antimicrobial peptides and modulation of intracellular Toll-like receptors (TLRs) expression in response to agonist challenge. In this report, we provide evidences that LTB4 acts on nucleotide-binging oligomerization domain 2 (NOD2) pathway to enhance immune response against influenza A infection. Infected mice receiving LTB4 show improved survival, lung architecture and reduced lung viral loads as compared to placebo-treated animals. NOD2 and its downstream adaptor protein IPS-1 have been found to be essential for LTB4-mediated effects against IAV infection, as absence of NOD2 or IPS-1 diminished its capacity to control viral infection. Treatment of IAV-infected mice with LTB4 induces an increased activation of IPS-1-IRF3 axis leading to an enhanced production of IFNβ in lungs of infected mice. LTB4 also has the ability to act on the RICK-NF-κB axis since administration of LTB4 to mice challenged with MDP markedly increases the secretion of IL-6 and TNFα in lungs of mice. TAK1 appears to be essential to the action of LTB4 on NOD2 pathway since pretreatment of MEFs with TAK1 inhibitor prior stimulation with IAV or MDP strongly abrogated the potentiating effects of LTB4 on both IFNβ and cytokine secretion. Together, our results demonstrate that LTB4, through its ability to activate TAK1, potentiates both IPS-1 and RICK axis of the NOD2 pathway to improve host innate responses.

Topics: Adaptor Proteins, Signal Transducing; Animals; Immunity, Innate; Inflammation; Interferon Regulatory Factor-3; Interferon-beta; Interleukin-6; Leukotriene B4; Lipopolysaccharides; Lung; MAP Kinase Kinase Kinases; Mice; Mice, Inbred C57BL; NF-kappa B; Nod2 Signaling Adaptor Protein; Orthomyxoviridae; Orthomyxoviridae Infections; Signal Transduction

Acute bronchitis (AB) is a common lung condition characterized by inflammation of the large bronchi in response to infection. Bronchipret(®) syrup (BRO), a fixed combination of thyme and ivy extracts has been effectively used for the treatment of AB. Combining in vivo and mechanistic in vitro studies we aimed to provide a better understanding of the therapeutic potential of BRO on key aspects of AB and to identify potential mechanisms of action.. Bronchoalveolitis in rats was induced by intratracheal LPS instillation. BRO was administered p.o. once daily at 1- to 10-fold equivalents of the human daily dose. Animals were sacrificed 24-72 h post LPS challenge to analyze leukocyte numbers in lung tissue, bronchoalveolar lavage fluid (BALF) and blood as well as goblet cells in bronchial epithelium. Inhibitory effects of BRO analogue on leukotriene (LT) production were determined in human neutrophils and monocytes as well as on isolated 5-lipoxygenase (5-LO).. BRO significantly reversed the LPS-induced increase in leukocyte numbers in lung tissue, BALF and blood as well as goblet cell numbers in bronchial epithelium. In vitro, BRO analogue suppressed cellular release of LTB4 (IC50 = 36 µg⋅ml(-1)) and cysLT (IC50 = 10 µg⋅ml(-1)) and inhibited the activity of isolated 5-LO (IC50 = 19 µg⋅ml(-1)).. BRO exerts significant anti-inflammatory effects and attenuates goblet cell metaplasia in LPS-induced bronchoalveolitis in vivo potentially via interference with 5-LO/LT signaling. These effects may contribute to its observed clinical efficacy in AB.

Topics: Animals; Bronchitis; Bronchoalveolar Lavage Fluid; Cells, Cultured; Disease Models, Animal; Goblet Cells; Humans; Hyperplasia; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Male; Monocytes; Neutrophils; Plant Extracts; Rats; Rats, Wistar; Thymol; Thymus Plant

The activation and infiltration of polymorphonuclear neutrophils (PMN) are critical key steps in inflammation. PMN-mediated inflammation is limited by anti-inflammatory and pro-resolving mechanisms, including specialized pro-resolving lipid mediators (SPM). We examined the effects of 15-epi-LXA4 on inflammation and the biosynthesis of pro-inflammatory mediators, such as prostaglandins, leukotriene B4 and various hydroxyeicosatetraenoic acids and SPM, in an oxazolone (OXA)-induced hypersensitivity model for dermal inflammation. 15-epi-LXA4 (100 μM, 5 μL subcutaneously injected) significantly (P < 0.05) reduced inflammation in skin, 24 hours after the OXA challenge, as compared to skin treated with vehicle. No significant influence on the biosynthesis of prostaglandins or leukotriene B4 was observed, whereas the level of 15S-hydroxy-eicosatetraenoic acid was significantly (P < 0.05) lower in the skin areas treated with 15-epi-LXA4. In spite of the use of a fully validated analytical procedure, no SPM were detected in the biological samples. To investigate the reason for the lack of analytical signal, we tried to mimic the production of SPM (lipoxins, resolvins, maresin and protectin) by injecting them subcutaneously into the skin of mice and studying the in vivo availability and distribution of the compounds. All analytes showed very little lateral distribution in skin tissue and their levels were markedly decreased (> 95%) 2 hours after injection. However, docosahexaenoic acid derivatives were biologically more stable than SPM derived from arachidonic acid or eicosapentaenoic acid.

Topics: Animals; Calibration; Chromatography, Liquid; Cyclooxygenase 2; Dermis; Hydroxyeicosatetraenoic Acids; Inflammation; Inflammation Mediators; Injections, Subcutaneous; Leukotriene B4; Lipids; Lipoxins; Luminescent Measurements; Mass Spectrometry; Mice, Inbred C57BL; Oxazolone; Peptidylprolyl Isomerase; Reproducibility of Results; Ribosomal Proteins

Myocardial infarction (MI) is one of the leading causes of death worldwide. Oxidative stress and inflammation play vital role in the development of MI. The Indian basil or Tulsi (Ocimum sanctum Linn.), owing to its antioxidant potential, is used in the traditional system of Indian medicine to treat various disorders. We evaluated methanolic extract of O. sanctum (Tulsi) leaves on inflammation in isoproterenol (ISP) induced MI in rats. ISP-induced MI increased the levels of cardiac markers, phospholipases and phospholipid content. However, the same were reduced on pre-treatment with methanolic extract of O. sanctum leaves. The activities of 5-lipoxygenase and cycloxygenase-2 and levels of leukotriene B4 and thromboxane B2 were also elevated in ISP-treated rats, which were significantly decreased (P < 0.001) in extract pre-treated rats. The enhanced mRNA expressions of nuclear factor kappa-B, 5-lipoxygenase activating protein and receptor for leukotriene B4 on MI induction, were considerably reduced (P < 0.001) on extract pre-treatment. Histopathological analysis also confirmed the findings. The results also revealed the high phenolic content of methanolic extract of O. sanctum leaves. The study demonstrated that methanolic extract of Tulsi leaves can decrease inflammation in the cardiac tissue of ISP-induced MI in rats and its effect may be through downregulation of oxidative stress and arachidonic acid pathway. This cardioprotective effect may be due to the high phenolic content of methanolic extract of O. sanctum leaves.

Topics: Animals; Antioxidants; Disease Models, Animal; Inflammation; Isoproterenol; Leukotriene B4; Male; Medicine, Traditional; Methanol; Myocardial Infarction; NF-kappa B; Ocimum; Oxidative Stress; Phenols; Phospholipids; Plant Extracts; Plant Leaves; Rats; Rats, Sprague-Dawley; RNA, Messenger; Thromboxane B2

Postsepsis lung injury is a common clinical problem associated with significant morbidity and mortality. Leukotrienes (LTs) are important lipid mediators of infection and inflammation derived from the 5-lipoxygenase (5-LO) metabolism of arachidonate with the potential to contribute to lung damage after sepsis. To test the hypothesis that LTs are mediators of lung injury after sepsis, we assessed lung structure, inflammatory mediators, and mechanical changes after cecal ligation and puncture surgery in wild-type (WT) and 5-LO knockout (5-LO(-/-)) mice and in WT mice treated with a pharmacologic LT synthesis inhibitor (MK886) and LT receptor antagonists (CP105,696 and montelukast). Sixteen hours after surgery, WT animals exhibited severe lung injury (by histological analysis), substantial mechanical impairment (i.e., an increase in static lung elastance), an increase in neutrophil infiltration, and high levels of LTB4, cysteinyl-LTs (cys-LTs), prostaglandin E2, IL-1β, IL-6, IL-10, IL-17, KC (CXCL1), and monocyte chemotactic protein-1 (CCL2) in lung tissue and plasma. 5-LO(-/-) mice and WT mice treated with a pharmacologic 5-LO inhibitor were significantly protected from lung inflammation and injury. Selective antagonists for BLT1 or cys-LT1, the high-affinity receptors for LTB4 and cys-LTs, respectively, were insufficient to provide protection when used alone. These results point to an important role for 5-LO products in sepsis-induced lung injury and suggest that the use of 5-LO inhibitors may be of therapeutic benefit clinically.

Topics: Animals; Arachidonate 5-Lipoxygenase; Cecum; Cytokines; Inflammation; Leukotriene Antagonists; Leukotriene B4; Lung Injury; Mice; Mice, Inbred C57BL; Neutrophil Infiltration; Receptors, Leukotriene; Receptors, Leukotriene B4; Sepsis; Signal Transduction

Leukotriene (LT) B(4) is a powerful proinflammatory lipid mediator and triggers adherence to the endothelium, activates and recruits leukocytes to the site of injury. When formed in excess, LTB(4) plays a pathogenic role and may sustain chronic inflammation in diseases such as asthma, rheumatoid arthritis, and inflammatory bowel disease. Recent investigations have also indicated that LTB(4) is involved in cardiovascular diseases.. As the 5-lipoxygenase pathway involves several discrete, tightly coupled, enzymes, which convert the substrate, 'step by step', into bioactive products, several different strategies have been used to target LTB(4) as a means to treat inflammation. Here, we discuss recent findings regarding the development of selective enzyme inhibitors and antagonists for LTB(4) receptors, as well as their application in preclinical and clinical studies.. Components of the 5-lipoxygenase pathway have received considerable attention as candidate drug targets resulting in one new class of medications against asthma, that is, the antileukotrienes. However, efforts to specifically target LTB(4) have not yet been fruitful in the clinical setting, in spite of very promising preclinical data. Recently, crystal structures along with hitherto unknown functions of key enzymes in the leukotriene cascade have emerged, offering new opportunities for drug development and, with time, pharmacological intervention in LTB(4)-mediated pathologies.

Topics: Arachidonate 5-Lipoxygenase; Humans; Inflammation; Leukotriene B4

MicroRNAs are known to control TLR activation in phagocytes. We have shown that leukotriene (LT) B4 (LTB4) positively regulates macrophage MyD88 expression by decreasing suppressor of cytokine signaling-1 (SOCS-1) mRNA stability. In this study, we investigated the possibility that LTB4 control of MyD88 expression involves the generation of microRNAs. Our data show that LTB4, via its receptor B leukotriene receptor 1 (BLT1) and Gαi signaling, increased macrophage expression of inflammatory microRNAs, including miR-155, miR-146b, and miR-125b. LTB4-mediated miR-155 generation was attributable to activating protein-1 activation. Furthermore, macrophage transfection with antagomirs against miR-155 and miR-146b prevented both the LTB4-mediated decrease in SOCS-1 and increase in MyD88. Transfection with miR-155 and miR-146b mimics decreased SOCS-1 levels, increased MyD88 expression, and restored TLR4 responsiveness in both wild type and LT-deficient macrophages. To our knowledge, our data unveil a heretofore unrecognized role for the GPCR BLT1 in controlling expression of microRNAs that regulate MyD88-dependent activation of macrophages.

Topics: Animals; Female; Gene Expression Regulation; GTP-Binding Protein alpha Subunits; Inflammation; Leukotriene B4; Macrophage Activation; Macrophages, Peritoneal; Mice; Mice, Knockout; MicroRNAs; Myeloid Differentiation Factor 88; Receptors, Leukotriene B4; Signal Transduction; Suppressor of Cytokine Signaling 1 Protein; Suppressor of Cytokine Signaling Proteins

Inflammation dysregulation in placenta is implicated in the pathogenesis of numerous pregnancy complications. Glucocorticoids (GCs), universally considered anti-inflammatory, can also exert proinflammatory actions under some conditions, whereas whether and how GCs promote placental inflammation have not been intensively investigated. In this paper we report the opposing regulation of rat placental inflammation by synthetic GC dexamethasone (Dex). When Dex was subcutaneously injected 1 h after we administered an intraperitoneal lipopolysaccharide (LPS) challenge, neutrophil infiltration and proinflammatory Il1b, Il6, and Tnfa expression in rat placenta were significantly reduced. In contrast, Dex pretreatment for 24 h potentiated rat placental proinflammatory response to LPS and delayed inflammation resolution, which involved MAPKs and NF-kappaB activation. Mechanically, Dex pretreatment promoted 5-lipoxygenase (ALOX5) activation and increased leukotriene B4 production, whereas it inhibited the anti-inflammatory and proresolving lipid mediator lipoxin A4 (LXA4) biosynthesis in rat placenta via downregulating ALOX15 and ALOX15B expression. Moreover, LXA4 supplementation dampened Dex-potentiated placental inflammation and suppressed Dex-mediated ALOX5 activation in vivo and in vitro. Taken together, these findings suggest that GCs exposure could promote placental inflammation initiation and delay resolution via disrupting LXA4 biosynthesis.

Topics: Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acid; Cell Line; Dexamethasone; Dinoprostone; Female; Glucocorticoids; Humans; Inflammation; Leukotriene B4; Lipopolysaccharides; Lipoxins; MAP Kinase Signaling System; NF-kappa B; Placenta; Pregnancy; Rats; Rats, Sprague-Dawley

Inflammatory responses to infection and injury must be restrained and negatively regulated to minimize damage to host tissue. One proposed mechanism involves enzymatic inactivation of the pro-inflammatory mediator leukotriene B4, but it is difficult to dissect the roles of various metabolic enzymes and pathways. A primary candidate for a regulatory pathway is omega oxidation of leukotriene B4 in neutrophils, presumptively by CYP4F3A in humans and CYP4F18 in mice. This pathway generates ω, ω-1, and ω-2 hydroxylated products of leukotriene B4, depending on species. We created mouse models targeting exons 8 and 9 of the Cyp4f18 allele that allows both conventional and conditional knockouts of Cyp4f18. Neutrophils from wild-type mice convert leukotriene B4 to 19-hydroxy leukotriene B4, and to a lesser extent 18-hydroxy leukotriene B4, whereas these products were not detected in neutrophils from conventional Cyp4f18 knockouts. A mouse model of renal ischemia-reperfusion injury was used to investigate the consequences of loss of CYP4F18 in vivo. There were no significant changes in infiltration of neutrophils and other leukocytes into kidney tissue as determined by flow cytometry and immunohistochemistry, or renal injury as assessed by histological scoring and measurement of blood urea nitrogen. It is concluded that CYP4F18 is necessary for omega oxidation of leukotriene B4 in neutrophils, and is not compensated by other CYP enzymes, but loss of this metabolic pathway is not sufficient to impact inflammation and injury following renal ischemia-reperfusion in mice.

Topics: Animals; Cytochrome P-450 Enzyme System; Cytochrome P450 Family 4; Disease Models, Animal; Humans; Inflammation; Kidney; Leukotriene B4; Mice; Mice, Knockout; Neutrophils; Reperfusion Injury

Airway disease in cystic fibrosis (CF) is characterised by impaired mucociliary clearance, persistent bacterial infection and neutrophilic inflammation. Lipoxin A4 (LXA4) initiates the active resolution of inflammation and promotes airway surface hydration in CF models. 15-Lipoxygenase (LO) plays a central role in the "class switch" of eicosanoid mediator biosynthesis from leukotrienes to lipoxins, initiating the active resolution of inflammation. We hypothesised that defective eicosanoid mediator class switching contributes to the failure to resolve inflammation in CF lung disease. Using bronchoalveolar lavage (BAL) samples from 46 children with CF and 19 paediatric controls we demonstrate that the ratio of LXA4 to leukotriene B4 (LTB4) is depressed in CF BAL (p<0.01), even in the absence of infection (p<0.001). Furthermore, 15-LO2 transcripts were significantly less abundant in CF BAL samples (p<0.05). In control BAL, there were positive relationships between 15-LO2 transcript abundance and LXA4/LTB4 ratio (p=0.01, r=0.66) and with percentage macrophage composition of the BAL fluid (p<0.001, r=0.82), which were absent in CF. Impoverished 15-LO2 expression and depression of the LXA4/LTB4 ratio are observed in paediatric CF BAL. These observations provide mechanistic insights into the failure to resolve inflammation in the CF lung.

Topics: Anti-Bacterial Agents; Arachidonate 15-Lipoxygenase; Bronchoalveolar Lavage Fluid; Child; Child, Preschool; Cystic Fibrosis; Female; Humans; Inflammation; Leukotriene A4; Leukotriene B4; Lipoxins; Longitudinal Studies; Lung; Lung Diseases; Macrophages, Alveolar; Male; Neutrophils

In humans, LL-37 and eicosanoids are important mediators of inflammation and immune responses. Here we report that LL-37 promotes leukotriene B4 (LTB4) and thromboxane A2 (TXA2) generation by human monocyte-derived macrophages (HMDMs). LL-37 evokes calcium mobilization apparently via the P2X7 receptor (P2X7R), activation of ERK1/2 and p38 MAPKs, as well as cytosolic phospholipase A2 (cPLA2) and 5-lipoxygenase in HMDMs, leading to an early (1 h) release of LTB4. Similarly, TXA2 production at an early time involved the same signaling sequence along an LL-37-P2X7R-cPLA2-cyclooxygenase-1 (COX-1) axis. However, at later (6-8 h) time points, internalized LL-37 up-regulates COX-2 expression, promoting TXA2 production. Furthermore, intraperitoneal injection of mice with murine cathelicidin-related antimicrobial peptide (mCRAMP) induces significantly higher levels of LTB4 and TXA2 in mouse ascites rich in macrophages. Conversely, cathelicidin-deficient (Cnlp(-/-)) mice produce much less LTB4 and TXB2 in vivo in response to TNF-α compared with control mice. We conclude that LL-37 elicits a biphasic release of eicosanoids in macrophages with early, Ca(2+)-dependent formation of LTB4 and TXA2 followed by a late peak of TXA2, generated via induction of COX-2 by internalized LL-37, thus allowing eicosanoid production in a temporally controlled manner. Moreover, our findings provide evidence that LL-37 is an endogenous regulator of eicosanoid-dependent inflammatory responses in vivo.

Topics: Amino Acid Sequence; Animals; Antimicrobial Cationic Peptides; Arachidonate 5-Lipoxygenase; Calcium Signaling; Cathelicidins; Cells, Cultured; Eicosanoids; Humans; Inflammation; Leukotriene B4; Macrophages; Male; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Molecular Sequence Data; Peritonitis; Phospholipases A2, Cytosolic; Phosphorylation; Prostaglandin-Endoperoxide Synthases; Protein Kinase Inhibitors; Protein Processing, Post-Translational; Receptors, Purinergic P2X7; Recombinant Proteins; Thromboxane A2; Tumor Necrosis Factor-alpha

 Inflammation and oxidative stress play an essential role in the pathogenesis of chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD)..  The aim of the study was to evaluate the echocardiographic parameters of the left and right ventricular functions in patients with COPD with or without CVD and in healthy controls, and to establish their relationships with biomarkers of inflammation and oxidative stress..  The study included 24 patients with COPD and CVD, 20 patients with COPD, and 16 healthy controls. Physical examination, spirometry, and echocardiography were performed in all participants, and blood samples were collected. The levels of 8‑isoprostane, leukotriene B4, and interleukin 8 were determined in the blood and exhaled breath condensate (EBC)..  In patients with COPD, the left ventricular ejection fraction was lower than in healthy controls (58.84% ±9.57% vs. 65.50% ±3.35%, P <0.01); moreover, it was lower in patients with COPD and CVD than in those without comorbidities (54.29% ±10.58% vs. 64.30% ±3.74%, P <0.01). The systolic and diastolic functions of the right ventricle were lower in patients with COPD than in the control group, while systolic pulmonary arterial pressure was significantly higher in patients with COPD than in the control group (37.04 ±7.6 mmHg vs. 28.12 ±4.44 mmHg, P = 0.01). Some echocardiographic parameters of the left and right ventricular functions correlated with the concentrations of inflammatory markers both in serum and EBC..  The echocardiographic parameters of cardiac function correlate with the markers of inflammation in patients with COPD, which emphasizes the inflammatory background of CVD.

Topics: Aged; Biomarkers; Cardiovascular Diseases; Diastole; Dinoprost; Echocardiography; Female; Heart Ventricles; Humans; Inflammation; Interleukin-8; Leukotriene B4; Male; Middle Aged; Pulmonary Disease, Chronic Obstructive; Systole; Ventricular Function, Left; Ventricular Function, Right

Cardiolipin (CL) is a phospholipid with an unusual dimeric structure containing four double-bonds and is easily oxidized. CL is present in mitochondria. Here we explored potential pro-inflammatory properties implicated in cardiovascular disease (CVD): activation of endothelial cells, 5-lipoxygenase (5-LOX) and leukotriene B4 (LTB4), by oxidized CL (oxCL) and inhibitory effects of Annexin A5, an antithrombotic and antiinflammatory plasma protein.. In monocytes/macrophages and neutrophils, calcium mobilization was monitored spectrophotometrically with Fura-2 and synthesis of LTB4 was analyzed by EIA. Expression of adhesion molecules on endothelial cells was studied by FACScan. Binding of Annexin A5 were analyzed by ELISA. The mRNA expression of 5-LOX and cyclooxygenase-2 was assessed by Real-Time PCR.. We demonstrate that oxCL but not its non-oxidized counterpart CL induces biosynthesis of LTB4 and increases intracellular concentrations of calcium in monocytes/macrophages and neutrophils. oxCL rather than CL selectively elevates gene expression of 5-LOX but not COX-2 in human macrophages. Furthermore, oxCL but not CL raises levels of adhesion molecules ICAM-1 and VCAM-1 in endothelial cells. Annexin A5 can bind oxCL to abolish all these oxCL-induced effects.. oxCL may promote inflammation and related diseases especially in conditions involving unresolved apoptosis and necrosis, such as atherosclerosis, where free oxCL is likely to be released from liberated mitochondria. Increased intracellular calcium could activate 5-LOX to produce Leukotriene B4 (LTB4). Annexin A5 inhibits the pro-inflammatory effects of oxCL and its potential therapeutic use when oxCL is implicated in inflammation could be of interest.

Topics: Annexin A5; Arachidonate 5-Lipoxygenase; Calcium; Cardiolipins; Humans; Inflammation; Inflammation Mediators; Intercellular Adhesion Molecule-1; Leukocytes, Mononuclear; Leukotriene B4; Macrophages; Neutrophils; Oxidation-Reduction; Vascular Cell Adhesion Molecule-1

Dramatic shifts in the Western diet have led to a marked increase in the dietary intake of the n-6 polyunsaturated fatty acid (PUFA), linoleic acid (LA). Dietary LA can then be converted to arachidonic acid (ARA) utilizing three enzymatic steps. Two of these steps are encoded for by the fatty acid desaturase (FADS) cluster (chromosome 11, 11q12.2-q13) and certain genetic variants within the cluster are highly associated with ARA levels. However, no study to date has examined whether these variants further influence pro-inflammatory, cyclooxygenase and lipoxygenase eicosanoid products. This study examined the impact of a highly influential FADS SNP, rs174537 on leukotriene, HETE, prostaglandin, and thromboxane biosynthesis in stimulated whole blood. Thirty subjects were genotyped at rs174537 (GG, n = 11; GT, n = 13; TT, n = 6), a panel of fatty acids from whole serum was analyzed, and precursor-to-product PUFA ratios were calculated as a marker of the capacity of tissues (particularly the liver) to synthesize long chain PUFAs. Eicosanoids produced by stimulated human blood were measured by LC-MS/MS. We observed an association between rs174537 and the ratio of ARA/LA, leukotriene B4, and 5-HETE but no effect on levels of cyclooxygenase products. Our results suggest that variation at rs174537 not only impacts the synthesis of ARA but the overall capacity of whole blood to synthesize 5-lipoxygenase products; these genotype-related changes in eicosanoid levels could have important implications in a variety of inflammatory diseases.

Topics: Adult; Arachidonic Acid; Delta-5 Fatty Acid Desaturase; Diet, Western; Eicosanoids; Fatty Acid Desaturases; Female; Humans; Inflammation; Inflammation Mediators; Leukotriene B4; Linoleic Acid; Metabolic Networks and Pathways; Middle Aged; Multigene Family; Polymorphism, Single Nucleotide; Young Adult

We studied the effect of lipopolysaccharide (LPS), proinflammatory cytokines (tumor necrosis factor α [TNF-α] and interleukin [IL]-1β), and anti-inflammatory cytokines (IL-4 and IL-10) on leukotriene (LT) A4 hydrolase and LTC4 synthase (LTCS) protein expression in, and LTB4 and LTC4 secretion from, an inflamed porcine endometrium. On day 3 of the estrous cycle (day 0 of the study), 50 mL of either saline or Escherichia coli suspension (10(9) CFU/mL) was injected into each uterine horn of gilts (n = 12 per group). Endometrial explants, obtained 8 and 16 days later, were incubated for 24 h with LPS (10 or 100 ng/mL of medium), TNF-α, IL-1β, IL-4, and IL-10 (each cytokine: 1 or 10 ng/mL of medium). Although acute endometritis developed in all bacteria-inoculated gilts, a severe form of acute endometritis was diagnosed more often on day 8 of the study than on day 16. The amount of the LTA4 hydrolase (LTAH) protein in the inflamed endometrium on day 8 was greater after applying the lower dose of TNF-α (P < 0.001) and both doses of IL-1β (P < 0.001) and IL-4 (1 ng, P < 0.01 and 10 ng, P < 0.001) than in the saline-treated uteri. A similar situation was observed in the case of the inflamed tissue on day 16 in response to LPS (100 ng, P < 0.01), TNF-α (10 ng, P < 0.05), and IL-4 (1 ng, P < 0.001). The content of LTC4 synthase in the inflamed endometrium on day 8 was reduced by LPS (100 ng, P < 0.05), IL-1β (10 ng, P < 0.05), IL-4 (1 and 10 ng, P < 0.05), and IL-10 (1 ng, P < 0.01) but increased after the application of LPS (100 ng, P < 0.05) and TNF-α (1 and 10 ng, P < 0.001), IL-1β, and IL-4 (1 ng, P < 0.05 and 10 ng, P < 0.001) on day 16. On day 8, endometrial secretion of LTB4 from the saline-injected and E coli-injected organs was similar in response to all of the used mediators. On the other hand, the contents of LTB4 in the medium decreased after incubating the inflamed tissues from day 16 with TNF-α (1 ng, P < 0.05 and 10 ng, P < 0.01), IL-1β (1 ng, P < 0.01), and IL-10 (10 ng, P < 0.05) compared with the saline-treated ones. Secretion of LTC4 from the inflamed uteri on day 8 was elevated by the lower doses of TNF-α (P < 0.01) and IL-10 (P < 0.05), whereas on day 16, such an effect occurred in response to the higher doses of IL-4 (P < 0.01) and IL-10 (P < 0.05). The obtained results show that pro- and anti-inflammatory mediators participate in the synthesis/secretion of LTs from an inflamed porcine endometrium. Our data suggest that inflammatory mediators

Topics: Animals; Cytokines; Endometriosis; Endometrium; Epoxide Hydrolases; Escherichia coli Infections; Female; Gene Expression Regulation; Glutathione Transferase; Inflammation; Leukotriene B4; Leukotriene C4; Lipopolysaccharides; Swine; Swine Diseases

To explain the successful treatment of various inflammatory diseases by using intensive red light, a non-linear theory is presented for the interaction of electric dipoles with light involving frequency doubling. It is applied to analyze the influence of light on organic molecules with permanent electric dipoles. The molecule 5-hydroxy-12-oxo-(5S,6Z,8E,10E,14Z)-6,8,10,14-eicosatetraenoic acid, 12-oxo-leukotriene B4 (12-Oxo-LTB4, an intermediate in the lipoxygenase-catalyzed path of arachidonic acid metabolism), is suspected to play a major role in the healing process, as, first, it plays a key role in the metabolism of leukotriene B4 (LTB4), which in many diseases acts as a source of inflammatory reactions; second, its dipole resonance is located at a wavelength of 316 nm, which can be excited by a 632 nm source through frequency doubling. From the structure of 12-Oxo-LTB4 and the knowledge of the partial charges of its 54 atoms, the equivalent values for dipole charges and dipole moment are derived. The power balance demonstrates that intensive red light with a power density of 0.4 W/cm2 transfers sufficient energy to 12-Oxo-LTB4 to render it biologically inactive. Hence, by generating a reactive high-energy leukotriene pathway intermediate, the law of mass action steers the chemical equilibrium to interrupt the inflammatory cascade.

Topics: Color; Computer Simulation; Energy Transfer; Inflammation; Leukotriene B4; Light; Models, Chemical; Models, Immunological; Models, Molecular; Molecular Conformation; Phototherapy; Radiation Dosage

Chemokines (CK) provide directional cues that mediate the recruitment of leukocytes to sites of inflammation. Broad-spectrum blockade of the CC-CK family, using the vaccinia virus 35K protein, has been shown to cause a potent reduction of systemic inflammation in models of atherosclerosis, vein graft disease and arthritis. We have used a cell membrane-targeted form of 35K, Mem35K, to probe whether cell-associated blockade of chemokine response is sufficient to reduce cell recruitment in inflammation. In Tie2cre mice, activation of a flox-stop Mem35K transgene directed conditional expression of Mem35K in leukocytes and endothelial cells, confirmed by Western blotting, flow cytometry and immunofluorescence microscopy. This conditional Mem35K expression was sufficient to increase cell surface CCL5 binding and reduce chemotaxis in vitro to CCL5, CCL2 and CCL3 but not to non-CC-CK chemoattractants, LTB4, C5a or chemerin. However, in vivo monocyte recruitment into the peritoneum driven by zymosan or CC-chemokine injection, which was demonstrated to be CC-CK dependent using CCR2-/- mice, was not reduced by Mem35K expression, despite the expression of functional Mem35K protein. These findings highlight differing requirements for cell-associated anti-inflammatory activity in in vitro and in vivo models.. Mem35K is a cell-associated CC-chemokine binding protein. Conditional Mem35K transgenic mice show expression Mem35K in leukocytes. Mem35K blocks in vitro primary macrophage chemotaxis specifically towards CC-chemokines. Mem35K expression is not sufficient to reduce inflammation in vivo. The requirements for anti-inflammatory activity in vitro and in vivo are different.

Topics: Animals; Cell Membrane; Chemokine CCL2; Chemokine CCL3; Chemokine CCL5; Chemokines; Chemotaxis; Complement C5a; Female; Flow Cytometry; Inflammation; Intercellular Signaling Peptides and Proteins; Leukocytes; Leukotriene B4; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Fluorescence; Receptors, Chemokine

The lipoxygenase isoform of 5-lipoxygenase (5-LOX) is reported to be overexpressed in human rheumatoid arthritis synovial tissue and involved in the progress of inflammatory arthritis. However, the detailed mechanism of how 5-lipoxygenase regulates the inflammatory response in arthritis synovial tissue is still unclear. The aim of this study was to investigate the involvement of lipoxygenase pathways in TNF-α-induced production of cytokines and chemokines. Human synovial fibroblasts from rheumatoid patients were used in this study. 5-LOX inhibitors and shRNA were used to examine the involvement of 5-LOX in TNF-α-induced cytokines and chemokines expression. The signaling pathways were examined by Western Blotting or immunofluorescence staining. The effect of 5-LOX inhibitor on TNF-α-induced chemokine expression and paw edema was also explored in vivo in C57BL/6 mice. Treatment with 5-LOX inhibitors significantly decreased TNF-α-induced pro-inflammatory mediators including interleukin-6 (IL-6) and monocyte chemo-attractant protein-1 (MCP-1) in human synovial fibroblasts. Knockdown of 5-LOX using shRNA exerted similar inhibitory effects. The abrogation of NF-κB activation was involved in the antagonizing effects of these inhibitors. Furthermore, 5-LOX inhibitor decreased TNF-α-induced up-regulation of serum MCP-1 level and paw edema in mouse model. Our results provide the evidence that the administration of 5-LOX inhibitors is able to ameliorate TNF-α-induced cytokine/chemokine release and paw edema, indicating that 5-LOX inhibitors may be developed for therapeutic treatment of inflammatory arthritis.

Topics: Animals; Arachidonate 5-Lipoxygenase; Chemokine CCL2; Edema; Enzyme Activation; Fibroblasts; Gene Knockout Techniques; Humans; I-kappa B Kinase; Inflammation; Interleukin-6; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred C57BL; Phosphorylation; Proteolysis; RNA Interference; RNA, Small Interfering; Synovial Membrane; Tumor Necrosis Factor-alpha

Leukotriene B4 (LTB4) is a proinflammatory lipid mediator that elicits eosinophil exocytosis, leading to allergic inflammation. However, the detailed intracellular signaling mechanisms of eosinophil exocytosis induced by LTB4 are poorly understood. Herein, we report that NADPH oxidase (NOX)2-derived reactive oxygen species (ROS)-mediated BLT1 migration to the cell surface is required for exocytosis in human eosinophils induced by LTB4.. Peripheral blood eosinophils were purified and stimulated for up to 60 min with LTB4. The signaling role of NOX2-derived ROS in BLT1-dependent exocytosis in LTB4-stimulated eosinophils was investigated.. Stimulating eosinophils with LTB4 induced intracellular ROS production and surface upregulation of the exocytosis marker protein CD63 via BLT1-mediated signaling. LTB4 induced p47(phox) phosphorylation and 91(phox) expression required for NOX2 activation in a BLT1-dependent manner. Pretreatment with NOX2 inhibitors, but not mitochondria inhibitor, prevented LTB4-induced ROS generation and exocytosis. At 30 min after stimulation with LTB4, BLT1 expression at the cell surface was upregulated. LTB4-triggered surface upregulation of BLT1 was also blocked by inhibition of ROS generation with NOX2 inhibitors. Moreover, stimulation for 30 min with LTB4 resulted in the interaction of BLT1 with NOX2 by immunoprecipitation. LTB4-induced ROS generation, surface upregulation of BLT1 and exocytosis was also inhibited by pretreatment with a lipid raft disruptor, protein kinase C inhibitor, or Src kinase inhibitor.. These results suggest that NOX2-derived ROS-mediated BLT1 trafficking to the cell surface plays a key role in the exocytosis of human eosinophils induced by LTB4.

Topics: Eosinophils; Exocytosis; Flow Cytometry; Humans; Immunoblotting; Inflammation; Leukocytes, Mononuclear; Leukotriene B4; Membrane Glycoproteins; NADPH Oxidase 2; NADPH Oxidases; Reactive Oxygen Species; Receptors, Leukotriene B4; Tetraspanin 30

Mutations in adenomatous polyposis coli (APC) gene are found in more than 80% of colorectal cancer (CRC) patients. The nuclear transcription factor Nrf2 plays a central role in the regulation of oxidative stress and inflammation. Previously, we have shown that chronic inflammation in Nrf2(-/-) (Nrf2 knockout; KO) mice resulted in higher expression of inflammatory markers and cytokines, coupled with higher inflammatory damage to the colonic crypt cells, as compared to the Nrf2(+/+) (wild type; WT) mice. Induction of mutation in the colon by administration of carcinogen, AOM prior to DSS-induced inflammation resulted in higher tumor incidence and numbers in Nrf2KO mice. These results indicate that Nrf2-dependent inhibition of inflammation appears to be critical in inhibiting mutation-initiated colorectal carcinogenesis. In this study, we aim to investigate if loss of Nrf2 would dose-dependently promote intestinal tumorigenesis in Apc(min/+) mice. To demonstrate the in vivo mechanisms, we constructed both Apc mutated and Nrf2 deficient strain Apc(min/+) mice with C57BL/6 Nrf2KO mice to obtain F1, Apc(min/+) ;Nrf2(+/-) and F2, Apc(min/+) ;Nrf2(-/-) mice. Nrf2KO decreased the protein expression of antioxidant enzyme NQO1 in Apc(min/+) . In contrast, Nrf2KO enhanced the expression of inflammatory markers such as COX-2, cPLA, LTB4 in Apc(min/+) . Finally, Nrf2KO resulted in higher level of PCNA and c-Myc expression in intestinal tissue, indicating the deficiency of Nrf2 promotes proliferation of intestinal crypt cells in Apc(min/+) . Taken together, our results suggest that Nrf2KO attenuates anti-oxidative stress pathway, induces inflammation, and increases proliferative potential in the intestinal crypts leading to enhanced intestinal carcinogenesis and adenomas in Apc(min/+) .

Topics: Adenomatous Polyposis Coli Protein; Animals; Cell Proliferation; Cell Transformation, Neoplastic; Colorectal Neoplasms; Gene Knockout Techniques; Inflammation; Intestinal Mucosa; Intestinal Polyps; Intestines; Leukotriene B4; Male; Mice; Mice, Knockout; NAD(P)H Dehydrogenase (Quinone); NF-E2-Related Factor 2; Oxidative Stress; Signal Transduction

Several emerging lines of evidence support an anti-inflammatory role for nicotinic acid (niacin); however, its role in the regulation of leukocyte migration in response to inflammatory stimuli has not been elucidated until now. Herein, we have examined the effect of nicotinic acid on neutrophil recruitment in experimentally induced inflammation. We demonstrated that nicotinic acid treatment inhibited interleukin (IL)-8-induced, leukotriene (LT)B4-induced, and carrageenan-induced neutrophil migration into the pleural cavity of BALB/c mice and reduced neutrophil rolling and adherence in a mouse cremaster muscle preparation. Surprisingly, nicotinic acid treatment increased the level of the neutrophil chemoattractant KC in response to carrageenan. These results suggest that nicotinic acid plays an important role in the regulation of inflammation due to its ability to inhibit the actions of the neutrophil chemoattractants IL-8 and LTB4. Further inhibition of chemoattractants leads to impairment of leukocyte rolling and adherence to the vascular endothelium in the microcirculation of inflamed tissues.

Topics: Animals; Anti-Inflammatory Agents; Carrageenan; Cell Adhesion; Chemokine CXCL1; Disease Models, Animal; Immune System Diseases; Inflammation; Interleukin-8; Leukocyte Disorders; Leukocyte Rolling; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Neutrophil Infiltration; Niacin; Pleural Cavity

Complement and the TLR family constitute two important branches of innate immunity. We previously showed attenuating effects on inflammation and thromogenicity by inhibiting the TLR coreceptor CD14 in porcine sepsis. In the present study, we explored the effect of the C5 and leukotriene B4 inhibitor Ornithodoros moubata complement inhibitor (OmCI; also known as coversin) alone and combined with anti-CD14 on the early inflammatory, hemostatic, and hemodynamic responses in porcine Escherichia coli-induced sepsis. Pigs were randomly allocated to negative controls (n = 6), positive controls (n = 8), intervention with OmCI (n = 8), or with OmCI and anti-CD14 (n = 8). OmCI ablated C5 activation and formation of the terminal complement complex and significantly decreased leukotriene B4 levels in septic pigs. Granulocyte tissue factor expression, formation of thrombin-antithrombin complexes (p < 0.001), and formation of TNF-α and IL-6 (p < 0.05) were efficiently inhibited by OmCI alone and abolished or strongly attenuated by the combination of OmCI and anti-CD14 (p < 0.001 for all). Additionally, the combined therapy attenuated the formation of plasminogen activator inhibitor-1 (p < 0.05), IL-1β, and IL-8, increased the formation of IL-10, and abolished the expression of wCD11R3 (CD11b) and the fall in neutrophil cell count (p < 0.001 for all). Finally, OmCI combined with anti-CD14 delayed increases in heart rate by 60 min (p < 0.05) and mean pulmonary artery pressure by 30 min (p < 0.01). Ex vivo studies confirmed the additional effect of combining anti-CD14 with OmCI. In conclusion, upstream inhibition of the key innate immunity molecules, C5 and CD14, is a potential broad-acting treatment regimen in sepsis as it efficiently attenuated inflammation and thrombogenicity and delayed hemodynamic changes.

Topics: Animals; Antithrombin III; Arterial Pressure; Arthropod Proteins; Carrier Proteins; CD11b Antigen; Complement C5; Escherichia coli; Escherichia coli Infections; Granulocyte-Macrophage Colony-Stimulating Factor; Heart Rate; Hemodynamics; Immunity, Innate; Inflammation; Interleukin-10; Interleukin-1beta; Interleukin-6; Interleukin-8; Leukocyte Count; Leukotriene B4; Lipopolysaccharide Receptors; Neutrophils; Peptide Hydrolases; Plasminogen Activator Inhibitor 1; Sepsis; Sus scrofa; Tumor Necrosis Factor-alpha

While tuberculosis susceptibility has historically been ascribed to failed inflammation, it is now known that an excess of leukotriene A4 hydrolase (LTA4H), which catalyzes the final step in leukotriene B4 (LTB4) synthesis, produces a hyperinflammatory state and tuberculosis susceptibility. Here we show that the LTB4-inactivating enzyme leukotriene B4 dehydrogenase/prostaglandin reductase 1 (LTB4DH/PTGR1) restricts inflammation and independently confers resistance to tuberculous infection. LTB4DH overexpression counters the susceptibility resulting from LTA4H excess while ltb4dh-deficient animals can be rescued pharmacologically by LTB4 receptor antagonists. These data place LTB4DH as a key modulator of TB susceptibility and suggest new tuberculosis therapeutic strategies.

Topics: Alcohol Oxidoreductases; Amino Acid Sequence; Animals; Humans; Inflammation; Leukotriene B4; Molecular Sequence Data; Mycobacterium Infections; Receptors, Leukotriene B4; Sequence Alignment; Tuberculosis; Zebrafish

Topics: Animals; Chemotactic Factors; Chemotaxis, Leukocyte; Humans; Inflammation; Leukotriene B4; Neutrophils

Insufficient oxygen delivery to organs leads to tissue dysfunction and cell death. Reperfusion, although vital to organ survival, initiates an inflammatory response that may both aggravate local tissue injury and elicit remote organ damage. Polymorphonuclear neutrophil (PMN) trafficking to remote organs following ischaemia/reperfusion (I/R) is associated with the release of lipid mediators, including leucotriene (LT) B4 , cysteinyl-LTs (CysLTs) and platelet-activating factor (PAF). Yet, their potentially cooperative role in regulating I/R-mediated inflammation has not been thoroughly assessed. The present study aimed to determine the cooperative role of lipid mediators in regulating PMN migration, tissue oedema and injury using selective receptor antagonists in selected models of I/R and dermal inflammation. Our results show that rabbits, pre-treated orally with BIIL 284 and/or WEB 2086 and MK-0571, were protected from remote tissue injury following I/R or dermal inflammation in an additive or synergistic manner when the animals were pre-treated with two drugs concomitantly. The functional selectivity of the antagonists towards their respective agonists was assessed in vitro, showing that neither BIIL 284 nor WEB 2086 prevented the inflammatory response to IL-8, C5a and zymosan-activated plasma stimulation. However, these agonists elicited LTB4 biosynthesis in isolated rabbit PMNs. Similarly, a cardioprotective effect of PAF and LTB4 receptor antagonists was shown following myocardial I/R in mice. Taken together, these results underscore the intricate involvement of LTB4 and PAF in each other's responses and provide further evidence that targeting both LTs and PAF receptors provides a much stronger anti-inflammatory effect, regulating PMN migration and oedema formation.

Topics: Amidines; Animals; Azepines; Biological Assay; Carbamates; Dermis; Disease Models, Animal; Extravasation of Diagnostic and Therapeutic Materials; Extremities; Inflammation; Leukotriene B4; Leukotrienes; Male; Mice; Mice, Inbred C57BL; Myocardial Ischemia; Neutrophil Infiltration; Platelet Activating Factor; Platelet Membrane Glycoproteins; Propionates; Quinolines; Rabbits; Receptors, G-Protein-Coupled; Receptors, Leukotriene; Reperfusion Injury; Triazoles

Leukotrienes constitute a group of lipid mediators, which may be subdivided into two groups, with leukotriene B4 on the one hand and cysteinyl leukotrienes on the other. Although leukotrienes are abundantly expressed in skin affected by diverse chronic inflammatory diseases, including atopic dermatitis, psoriasis, pemphigus vulgaris and bullous pemphigoid, their pathological roles in these diseases have remained elusive. Recent data now reveal that both leukotriene B4 and cysteinyl leukotrienes are indispensable in the pathogenesis of atopic dermatitis, with leukotriene B4 initiating the recruitment of inflammatory cells, particularly neutrophils and TH 2 cells into the skin, and cysteinyl leukotrienes later inducing characteristic structural alterations of chronically affected skin, specifically skin fibrosis and keratinocyte proliferation. Thus, these results reveal a sequential cooperation of LTB4 and cysteinyl leukotrienes to initiate and perpetuate allergic skin inflammation. These new insights highlight leukotrienes as promising therapeutic targets in allergic skin inflammation and should encourage more research into the role of leukotrienes in other inflammatory skin diseases.

Topics: Animals; Cell Proliferation; Dermatitis, Atopic; Fibrosis; Humans; Hypersensitivity; Inflammation; Keratinocytes; Leukotriene B4; Lipids; Mice; Neutrophils; Receptors, Leukotriene; Skin; Skin Diseases; Th2 Cells

The life span of neutrophilic granulocytes has a determining impact on the intensity and duration of neutrophil driven lung inflammation. Based on the compatible solute ectoine, we aimed to prevent anti-apoptotic reactions in neutrophils triggered by the inflammatory microenvironment in the lung. Neutrophils from chronic obstructive pulmonary disease patients and control individuals were exposed to inflammatory mediators and xenobiotics in the presence or absence of ectoine. The in vivo relevance of this approach was tested in xenobiotic-induced lung inflammation in rats. The reduction of apoptosis rates of ex vivo-exposed neutrophils from all study groups was significantly restored in the presence of ectoine. However, natural apoptosis rates not altered by inflammatory stimuli were not changed by ectoine. Mechanistic analyses demonstrated the preventive effect of ectoine on the induction of anti-apoptotic signalling. Neutrophilic lung inflammation induced by single or multiple expositions of animals to environmental particles was reduced after the therapeutic intervention with ectoine. Analyses of neutrophils from bronchoalveolar lavage indicate that the in vivo effect is due to the restoration of neutrophil apoptosis. Ectoine, a compound of the highly compliant group of compatible solutes, demonstrates a reproducible and robust effect on the resolution of lung inflammation.

Topics: Adult; Aged; Amino Acids, Diamino; Animals; Apoptosis; Case-Control Studies; Cells, Cultured; Emphysema; Female; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Inflammation; Leukotriene B4; Lung; Male; Middle Aged; Neutrophils; Phosphatidylinositol 3-Kinases; Pulmonary Disease, Chronic Obstructive; Rats; Rats, Inbred F344; Soot; Xenobiotics

Platelet-activating factor (PAF) and its receptor (PAFR) have been shown to be involved in several inflammatory events, including neutrophil chemoattraction and nociception. The present study addressed the role of PAF in the genesis of articular hyperalgesia in a model of joint inflammation. Zymosan-induced articular hyperalgesia, oedema and neutrophil migration were dose-dependently reduced following pretreatment with selective PAFR antagonists, UK74505 (5, 10 and 20 mg/kg) and PCA4248 (3, 10, 30 mg/kg). These parameters were also reduced in PAF receptor-deficient mice (PAFR(-/-)). The hyperalgesic action of PAF was further confirmed by the demonstration that joint injection of PAF induces a dose- (0.3, 1 and 3 μg/joint), time- and PAFR-dependent articular hyperalgesia and oedema. The PAF hyperalgesic mechanisms were dependent on prostaglandins, leukotrienes and neutrophils, as PAF-induced articular hyperalgesia was inhibited by indomethacin (COX inhibitor), MK886 (leukotrienes synthesis inhibitor) or fucoidan (leukocyte rolling inhibitor). Furthermore, PAF-induced hyperalgesia was reduced in 5-lypoxigenase-null mice. In corroboration of these findings, intra-articular injection of PAF promotes the production of LTB(4) as well as the recruitment of neutrophils to the joint. These results suggest that PAF may participate in the cascade of events involved in the genesis of articular inflammatory hyperalgesia via stimulation of prostaglandins, leukotrienes and neutrophil migration. Finally, targeting PAF action (e.g., with a PAFR antagonist) might provide a useful therapeutic approach to inhibit articular inflammatory hyperalgesia.

Topics: Animals; Dihydropyridines; Disease Models, Animal; Dose-Response Relationship, Drug; Hyperalgesia; Imidazoles; Immune System Diseases; Inflammation; Joint Diseases; Leukocyte Disorders; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Mice, Knockout; Neutrophils; Platelet Activating Factor; Platelet Membrane Glycoproteins; Prostaglandins; Receptors, G-Protein-Coupled; Time Factors; Zymosan

The polyherbal eye drop (Itone™) is a mixture of aqueous distillates of nineteen traditionally used ingredients that sum up to impart potency to the formulation and make it a useful adjunct in various ocular pathologies. However, as there have been no controlled experimental studies accounting to the above claim, therefore, the present study was designed to evaluate the polyherbal formulation (PHF) for antiangiogenic, anti-inflammatory, anticataract, antioxidant and cytotoxicity in addition to the evaluation of intraocular penetration of PHF in rabbit eyes using LC-MS/MS.. Antiangiogenic activity of the PHF was evaluated using in ovo chick chorio-allantoic membrane (CAM) assay and in vivo cautery induced corneal neovascularization assay in rats. Anticataract potential was evaluated using steroid induced cataract in developing chick embryos, sodium selenite induced cataract in rat pups and galactose induced cataract in rats. The antioxidant activity was evaluated using di-phenyl picryl hydrazyl (DPPH) radical scavenging assay. Anti-inflammatory activity was evaluated in vitro using inhibition of LTB4 formation in human WBCs and in vivo using carrageenan induced paw edema assay in rats. The cytotoxicity was evaluated against HeLa cancer cell lines using (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Furthermore evaluation of the intraocular penetration of the PHF was carried out in rabbit eyes via aqueous humor paracentesis and further analysis using LC-MS/MS.. PHF significantly inhibited VEGF induced proliferation of new blood vessels in CAM assay and inhibited the cautery induced corneal neovascularization in rats. Additionally, PHF showed noticeable delay in the progression of cataract in the selenite and galactose induced cataract models whereby the PHF treated lenses were graded for stages II and III respectively. However, the PHF did not show any anticataract activity in the hydrocortisone induced cataract model. Moreover, PHF exhibited anti-inflammatory activity whereby it showed 39.34% inhibition of LTB4 formation and significantly inhibited carrageenan induced paw edema in rats. Eight compounds of PHF viz. camphor, casticin, curcumin-II, quercetin, rosmarinic acid, γ-terpinene, β-pinene and dipentene exhibited transcorneal penetration in rabbit eyes.. The significant antiangiogenic and anti-inflammatory activities evinced by the PHF merits further investigation for ocular neovascular and inflammatory diseases in humans.

Topics: Angiogenesis Inhibitors; Animals; Anti-Inflammatory Agents; Aqueous Humor; Biphenyl Compounds; Blood Vessels; Carrageenan; Cataract; Chick Embryo; Cornea; Edema; Eye; Female; Galactose; HeLa Cells; Humans; Hydrocortisone; Inflammation; Lens, Crystalline; Leukocytes; Leukotriene B4; Male; Medicine, Ayurvedic; Models, Animal; Ophthalmic Solutions; Phytotherapy; Picrates; Plant Extracts; Rabbits; Rats; Rats, Wistar; Sodium Selenite; Steroids; Vascular Endothelial Growth Factor A

The impact of chronic inflammatory conditions on immune function is substantial, and the simultaneous application of anti-inflammatory and immune modulating modalities has potential for reducing inflammation-induced immune suppression. Sorghum-based foods, teas, beers, and extracts are used in traditional medicine, placing an importance on obtaining an increased understanding of the biological effects of sorghum. This study examined selected anti-inflammatory and immune-modulating properties in vitro of Jobelyn™, containing the polyphenol-rich leaf sheaths from a West African variant of Sorghum bicolor (SBLS). Freshly isolated primary human polymorphonuclear (PMN) and mononuclear cell subsets were used to test selected cellular functions in the absence versus presence of aqueous and ethanol extracts of SBLS. Both aqueous and nonaqueous compounds contributed to reduced reactive oxygen species formation by inflammatory PMN cells, and reduced the migration of these cells in response to the inflammatory chemoattractant leukotriene B4. Distinct effects were seen on lymphocyte and monocyte subsets in cultures of peripheral blood mononuclear cells. The aqueous extract of SBLS triggered robust upregulation of the CD69 activation marker on CD3- CD56+ natural killer (NK) cells, whereas the ethanol extract of SBLS triggered similar upregulation of CD69 on CD3+ CD56+ NKT cells, CD3+ T lymphocytes, and monocytes. This was accompanied by many-fold increases in the chemokines RANTES/CCL5, Mip-1α/CCL3, and MIP-1β/CCL4. Both aqueous and nonaqueous compounds contribute to anti-inflammatory effects, combined with multiple effects on immune cell activation status. These observations may help suggest mechanisms of action that contribute to the traditional use of sorghum-based products, beverages, and extracts for immune support.

Topics: Africa, Western; Anti-Inflammatory Agents; Antigens, CD; Cell Movement; Chemokine CCL3; Chemokine CCL4; Chemokine CCL5; Chemotactic Factors; Humans; Immunologic Factors; Inflammation; Killer Cells, Natural; Leukocytes, Mononuclear; Leukotriene B4; Monocytes; Plant Extracts; Plant Leaves; Polyphenols; Reactive Oxygen Species; Sorghum; T-Lymphocytes; Up-Regulation

The cholinergic antiinflammatory pathway (CAP), which terminates in the spleen, attenuates postoperative cognitive decline (PCD) in rodents. Surgical patients with metabolic syndrome exhibit exaggerated and persistent PCD that is reproduced in postoperative rats selectively bred for easy fatigability and that contain all features of metabolic syndrome (low-capacity runners [LCRs]). We compared the CAP and lipoxin A(4) (LXA(4)), another inflammation-resolving pathway in LCR, with its counterpart high-capacity runner (HCR) rats. Isoflurane-anesthetized LCR and HCR rats either underwent aseptic trauma involving tibial fracture (surgery) or not (sham). At postoperative d 3 (POD3), compared with HCR, LCR rats exhibited significantly exaggerated PCD (trace fear conditioning freezing time 43% versus 57%). Separate cohorts were killed at POD3 to collect plasma for LXA4 and to isolate splenic mononuclear cells (MNCs) to analyze CAP signaling, regulatory T cells (Tregs) and M2 macrophages (M2 Mφ). Under lipopolysaccharide (LPS) stimulation, tumor necrosis factor (TNF)-α produced by splenic MNCs was 117% higher in LCR sham and 52% higher in LCR surgery compared with HCR sham and surgery rats; LPS-stimulated TNF-α production could not be inhibited by an α7 nicotinic acetylcholine receptor agonist, whereas inhibition by the β(2) adrenergic agonist, salmeterol, was significantly less (-35%) than that obtained in HCR rats. Compared to HCR, sham and surgery LCR rats had reduced β(2) adrenergic receptor-expressing T lymphocytes (59%, 44%), Tregs (47%, 54%) and M2 Mφ (45%, 39%); surgical LCR rats' hippocampal M2 Mφ was 66% reduced, and plasma LXA4 was decreased by 120%. Rats with the metabolic syndrome have ineffective inflammation-resolving mechanisms that represent plausible reasons for the exaggerated and persistent PCD.

Topics: Animals; Anti-Inflammatory Agents; CD3 Complex; Cell Polarity; Choline; Cognition Disorders; Disease Models, Animal; Hippocampus; Inflammation; Leukotriene B4; Lipoxins; Lymphocyte Count; Macrophages; Male; Metabolic Syndrome; Physical Conditioning, Animal; Postoperative Period; Rats; Receptors, Adrenergic, beta-2; Signal Transduction; Spleen; T-Lymphocytes, Regulatory

Inflammation is a major factor shaping outcome during the early, acute phase of traumatic spinal cord injury (SCI). It is known that pro-inflammatory signaling within the injured spinal cord drives pathological alterations in neurosensory processing and shapes functional outcome early after injury. However, it is unclear whether inflammation persists into the chronic phase of injury or shapes sensory processing long after injury. To investigate these possibilities, we have performed biochemical and behavioral assessments 9 months after moderate thoracic spinal contusion injury in the rat. We have found that levels of the pro-inflammatory lipid mediators leukotriene B4 and prostaglandin E2 are elevated in the chronic spinal cord lesion site. Additionally, using metabolomic profiling, we have detected elevated levels of pro-oxidative and inflammatory metabolites, along with alterations in multiple biological pathways within the chronic lesion site. We found that 28 d treatment of chronically injured rats with the dual COX/5-LOX inhibitor licofelone elevated levels of endogenous anti-oxidant and anti-inflammatory metabolites within the lesion site. Furthermore, licofelone treatment reduced hypersensitivity of hindpaws to mechanical, but not thermal, stimulation, indicating that mechanical sensitivity is modulated by pro-inflammatory signaling in the chronic phase of injury. Together, these findings provide novel evidence of inflammation and oxidative stress within spinal cord tissue far into the chronic phase of SCI, and demonstrate a role for inflammatory modulation of mechanical sensitivity in the chronic phase of injury.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Dinoprostone; Enzyme-Linked Immunosorbent Assay; Female; Gas Chromatography-Mass Spectrometry; Hindlimb; Hot Temperature; Hyperalgesia; Inflammation; Leukotriene B4; Locomotion; Metabolomics; Oxidative Stress; Physical Stimulation; Pyrroles; Rats; Rats, Sprague-Dawley; Spinal Cord Injuries

Atherosclerosis is an inflammatory condition, and rupture of atherosclerotic plaques is a major cause of cardiovascular disease (CVD). Lysophosphatidylcholine (LPC) is generated in low-density lipoprotein (LDL) during oxidation and/or enzymatic modification and has been implicated in atherosclerosis. Annexin A5 (ANXA5) is an antithrombotic and atheroprotective plasma protein. Here, we demonstrate novel pro-inflammatory and atherogenic properties of LPC, and inhibitory effects of ANXA5.. Endothelial cells and macrophages (differentiated from, THP-1 a monocytic cell line) were co-cultured. Expression of MMP-9 and OxLDL uptake by macrophages were studied by flow cytometry. The effect of LPC on leukotriene B4 (LTB4) synthesis in macrophages was studied by enzyme immunoassay (EIA). Chemotactic properties of LPC were investigated using a mouse intra-peritoneal recruitment model.. Co-culture of macrophages and endothelial cells enhanced MMP-9 expression in both cell types. This effect was increased by LPC and diminished by ANXA5. Likewise, LPC induced LTB4 production by macrophages, whereas native LDL or phosphatidylcholine (PTC) had no effect. ANXA5 inhibited uptake of OxLDL in macrophages. LPC induced cell infiltration in vivo, as determined by increased cell count in mouse peritoneal exudates, and this effect was inhibited by ANXA5.. ANXA5 could potentially play an important protective role in both atherogenesis and atherosclerotic plaque rupture by reducing pro-inflammatory effects of OxLDL and LPC as well as inhibiting OxLDL binding and uptake by macrophages. The possibility that ANXA5 could be developed into a novel therapy against CVD deserves further study.

Topics: Animals; Annexin A5; Biological Transport; Cell Line; Cell Movement; Gene Expression Regulation, Enzymologic; Human Umbilical Vein Endothelial Cells; Humans; Inflammation; Leukotriene B4; Lipoproteins, LDL; Lysophosphatidylcholines; Macrophages; Matrix Metalloproteinase 9; Mice; Plaque, Atherosclerotic

Deposition of monosodium urate monohydrate (MSU) crystals in the joints promotes an intense inflammatory response and joint dysfunction. This study evaluated the role of the NLRP3 inflammasome and 5-lipoxygenase (5-LOX)-derived leukotriene B(4) (LTB(4) ) in driving tissue inflammation and hypernociception in a murine model of gout.. Gout was induced by injecting MSU crystals into the joints of mice. Wild-type mice and mice deficient in NLRP3, ASC, caspase 1, interleukin-1β (IL-1β), IL-1 receptor type I (IL-1RI), IL-18R, myeloid differentiation factor 88 (MyD88), or 5-LOX were used. Evaluations were performed to assess neutrophil influx, LTB(4) activity, cytokine (IL-1β, CXCL1) production (by enzyme-linked immunosorbent assay), synovial microvasculature cell adhesion (by intravital microscopy), and hypernociception. Cleaved caspase 1 and production of reactive oxygen species (ROS) were analyzed in macrophages by Western blotting and fluorometric assay, respectively.. Injection of MSU crystals into the knee joints of mice induced neutrophil influx and neutrophil-dependent hypernociception. MSU crystal-induced neutrophil influx was CXCR2-dependent and relied on the induction of CXCL1 in an NLRP3/ASC/caspase 1/IL-1β/MyD88-dependent manner. LTB(4) was produced rapidly after injection of MSU crystals, and this was necessary for caspase 1-dependent IL-1β production and consequent release of CXCR2-acting chemokines in vivo. In vitro, macrophages produced LTB(4) after MSU crystal injection, and LTB(4) was relevant in the MSU crystal-induced maturation of IL-1β. Mechanistically, LTB(4) drove MSU crystal-induced production of ROS and ROS-dependent activation of the NLRP3 inflammasome.. These results reveal the role of the NLRP3 inflammasome in mediating MSU crystal-induced inflammation and dysfunction of the joints, and highlight a previously unrecognized role of LTB(4) in driving NLRP3 inflammasome activation in response to MSU crystals, both in vitro and in vivo.

Topics: Animals; Carrier Proteins; Caspase 1; Cytokines; Gout; Hyperalgesia; Inflammasomes; Inflammation; Interleukin-1beta; Leukotriene B4; Macrophages; Male; Mice; Mice, Knockout; Neutrophil Infiltration; Neutrophils; NLR Family, Pyrin Domain-Containing 3 Protein; Reactive Oxygen Species; Synovial Membrane; Uric Acid

Nasal polyposis, a chronic inflammatory disease affecting the upper airways, is a valuable and accessible model to investigate the mechanisms underlying chronic inflammation. The main objective of this study was to investigate a potential involvement of the unfolded protein response (UPR) in the context of oxidative stress and inflammation in nasal epithelial cells from nasal polyps (NP).. Epithelial cells from NP (n = 20) and normal mucosa (Controls, n = 15) in primary culture were analyzed by global proteomic approach and cell biology techniques for the glucose-regulated protein 78 (GRP78), the spliced X-box-binding protein 1 (sXBP-1), the glucose-regulated protein 94 (GRP94), and the calreticulin (immunoblot, mass spectrometry, immunocytochemistry).. Proteomics analysis of human nasal epithelial cells in culture revealed the activation of the unfolded protein response in NP. Systematic cell biology and biochemical analysis of two markers (GRP78, sXBP-1) in the presence and absence of oxidative stress in NP showed a susceptibility of the unfolded protein response to oxidative stress compared to controls at least partially linked to an abnormal redox state of the protein disulfide-isomerase 4. This unfolded protein response was correlated with mitochondrial depolarization and secretion of interleukin 8 (IL-8) and leukotriene B4 (LTB4) and was prevented by mitochondrial antioxidant.. We show the existence of UPR in nasal epithelial cells that is linked to oxidative stress leading to IL-8 and LTB4 secretions. These mechanisms may participate in chronic inflammation in nasal polyposis.

Topics: Antioxidants; Cells, Cultured; Endoplasmic Reticulum Chaperone BiP; Epithelial Cells; Gene Expression Regulation; Humans; Inflammation; Interleukin-8; Leukotriene B4; Nasal Mucosa; Nasal Polyps; Oxidative Stress; Proteome; Proteomics; Unfolded Protein Response

Susceptibility to tuberculosis is historically ascribed to an inadequate immune response that fails to control infecting mycobacteria. In zebrafish, we find that susceptibility to Mycobacterium marinum can result from either inadequate or excessive acute inflammation. Modulation of the leukotriene A(4) hydrolase (LTA4H) locus, which controls the balance of pro- and anti-inflammatory eicosanoids, reveals two distinct molecular routes to mycobacterial susceptibility converging on dysregulated TNF levels: inadequate inflammation caused by excess lipoxins and hyperinflammation driven by excess leukotriene B(4). We identify therapies that specifically target each of these extremes. In humans, we identify a single nucleotide polymorphism in the LTA4H promoter that regulates its transcriptional activity. In tuberculous meningitis, the polymorphism is associated with inflammatory cell recruitment, patient survival and response to adjunctive anti-inflammatory therapy. Together, our findings suggest that host-directed therapies tailored to patient LTA4H genotypes may counter detrimental effects of either extreme of inflammation.

Topics: Animals; Disease Models, Animal; Humans; Inflammation; Leukotriene A4; Leukotriene B4; Lipoxins; Mitochondria; Mycobacterium Infections; Mycobacterium marinum; Polymorphism, Genetic; Polymorphism, Single Nucleotide; Promoter Regions, Genetic; Signal Transduction; Transcription, Genetic; Tuberculosis, Meningeal; Tumor Necrosis Factor-alpha; Zebrafish

Neutrophil recruitment to inflammation sites purportedly depends on sequential waves of chemoattractants. Current models propose that leukotriene B(4) (LTB(4)), a secondary chemoattractant secreted by neutrophils in response to primary chemoattractants such as formyl peptides, is important in initiating the inflammation process. In this study we demonstrate that LTB(4) plays a central role in neutrophil activation and migration to formyl peptides. We show that LTB(4) production dramatically amplifies formyl peptide-mediated neutrophil polarization and chemotaxis by regulating specific signaling pathways acting upstream of actin polymerization and MyoII phosphorylation. Importantly, by analyzing the migration of neutrophils isolated from wild-type mice and mice lacking the formyl peptide receptor 1, we demonstrate that LTB(4) acts as a signal to relay information from cell to cell over long distances. Together, our findings imply that LTB(4) is a signal-relay molecule that exquisitely regulates neutrophil chemotaxis to formyl peptides, which are produced at the core of inflammation sites.

Topics: Actins; Animals; Cell Communication; Cell Polarity; Chemotactic Factors; Chemotaxis, Leukocyte; Humans; Inflammation; Leukotriene B4; Mice; Mice, Knockout; Myosin Type II; Neutrophil Activation; Neutrophil Infiltration; Neutrophils; Receptors, Formyl Peptide; Signal Transduction

Ly6G is a glycosylphosphatidylinositol (GPI)-anchored protein of unknown function that is commonly targeted to induce experimental neutrophil depletion in mice. In the present study, we found that doses of anti-Ly6G Abs too low to produce sustained neutropenia remained capable of inhibiting experimental arthritis, leaving joint tissues free of infiltrating neutrophils. Thioglycollate-stimulated peritonitis was also attenuated. No alteration in neutrophil apoptosis was observed, implicating impaired recruitment. Indeed, Ly6G ligation abrogated neutrophil migration toward LTB(4) and other chemoattractants in a transwell system. Exploring the basis for this blockade, we identified colocalization of Ly6G and β2-integrins by confocal microscopy and confirmed close association by both coimmunoprecipitation and fluorescence lifetime imaging microscopy. Anti-Ly6G Ab impaired surface expression of β2-integrins in LTB(4)-stimulated neutrophils and mimicked CD11a blockade in inhibiting both ICAM-1 binding and firm adhesion to activated endothelium under flow conditions. Correspondingly, migration of β2-integrin-deficient neutrophils was no longer inhibited by anti-Ly6G. These results demonstrate that experimental targeting of Ly6G has functional effects on the neutrophil population and identify a previously unappreciated role for Ly6G as a modulator of neutrophil migration to sites of inflammation via a β2-integrin-dependent mechanism.

Topics: Animals; Antibodies; Antigens, Ly; Apoptosis; Arthritis; Biomarkers; Calcium; CD18 Antigens; Cell Movement; Down-Regulation; Inflammation; Joints; Leukotriene B4; Mice; Mice, Inbred C57BL; Neutrophil Activation; Neutrophil Infiltration; Neutrophils; Peritoneum; Receptors, Leukotriene B4; Signal Transduction

In response to pathogen recognition by Toll-like receptors (TLRs) on their cell surface, macrophages release lipid mediators and cytokines that are widely distributed throughout the body and play essential roles in host responses. Granulocyte macrophage colony-stimulating factor (GM-CSF) is important for the immune response during infections to improve the clearance of microorganisms. In this study, we examined the release of mediators in response to TLR2 ligands by bone marrow-derived macrophages (BMDMs) primed with GM-CSF. We demonstrated that when stimulated with TLR2 ligands, non-primed BMDMs preferentially produced PGE(2) in greater amounts than LTB(4). However, GM-CSF priming shifted the release of lipid mediators by BMDMs, resulting in a significant decrease of PGE(2) production in response to the same stimuli. The decrease of PGE(2) production from primed BMDMs was accompanied by a decrease in PGE-synthase mRNA expression and an increase in TNF-α and nitric oxide (NO) production. Moreover, some GM-CSF effects were potentiated by the addition of IFN-γ. Using a variety of TLR2 ligands, we established that PGE(2) release by GM-CSF-primed BMDMs was dependent on TLR2 co-receptors (TLR1, TLR6), CD14, MyD88 and the nuclear translocation of NFκB but was not dependent on peroxisome proliferator-activated receptor-γ (PPAR-γ) activation. Indeed, GM-CSF priming enhanced TLR2, TLR4 and MyD88 mRNA expression and phospho-IκBα formation. These findings demonstrate that GM-CSF drives BMDMs to present a profile relevant to the host during infections.

Topics: Adaptor Proteins, Signal Transducing; Animals; Bacteria; Dinoprostone; Down-Regulation; Female; Granulocyte-Macrophage Colony-Stimulating Factor; Inflammation; Interferon-gamma; Interleukin-10; Leukotriene B4; Ligands; Lipid Metabolism; Macrophages; Male; Mice; Mice, Inbred C57BL; Myeloid Differentiation Factor 88; NF-kappa B; Nitric Oxide; PPAR gamma; Protein Transport; RNA, Messenger; Toll-Like Receptor 2; Tumor Necrosis Factor-alpha

Mechanisms underlying delays in resolution programs of inflammation are of interest for many diseases. Here, we addressed delayed resolution of inflammation and identified specific microRNA (miR)-metabolipidomic signatures. Delayed resolution initiated by high-dose challenges decreased miR-219-5p expression along with increased leukotriene B(4) (5-fold) and decreased (~3-fold) specialized pro-resolving mediators, e.g. protectin D1. Resolvin (Rv)E1 and RvD1 (1 nM) reduced miR-219-5p in human macrophages, not shared by RvD2 or PD1. Since mature miR-219-5p is produced from pre-miRs miR-219-1 and miR-219-2, we co-expressed in human macrophages a 5-lipoxygenase (LOX) 3'UTR-luciferase reporter vector together with either miR-219-1 or miR-219-2. Only miR-219-2 reduced luciferase activity. Apoptotic neutrophils administered into inflamed exudates in vivo increased miR-219-2-3p expression and PD1/NPD1 levels as well as decreased leukotriene B(4). These results demonstrate that delayed resolution undermines endogenous resolution programs, altering miR-219-2 expression, increasing pro-inflammatory mediators and compromising SPM production that contribute to failed catabasis and homeostasis.

Topics: 3' Untranslated Regions; Acute Disease; Animals; Apoptosis; Arachidonate 5-Lipoxygenase; Cells, Cultured; Dinoprostone; Exudates and Transudates; Gene Expression; Humans; Inflammation; Inflammation Mediators; Leukotriene B4; Lipid Metabolism; Macrophages; Male; Mice; MicroRNAs; Neutrophils; Peritonitis; Prostaglandin D2; RNA Interference; Zymosan

Neutrophils are inflammatory cells that may contribute in a crucial way to the pathophysiology of steroid-resistant severe asthma. We previously reported that the nonessential amino acid l-glutamine (Gln) suppressed the recruitment of neutrophils into the airway in a murine model of asthma. In this study, we investigated the mechanisms by which Gln exerts beneficial effects in airway neutrophilia. We used the model we previously developed, which is suitable for examining sequential early asthmatic events, including neutrophil infiltration. Gln suppressed airway neutrophilia in a CXC chemokine-independent way. Airway neutrophilia was associated with cytosolic phospholipase A(2) (cPLA(2)) and 5-lipoxygenase (5-LO) activities. p38 MAPK, the upstream pathway of cPLA(2) and 5-LO, played a key role in inducing airway neutrophilia. Gln inhibited not only the phosphorylation of cPLA(2) and p38 MAPK but also leukotriene B(4) levels in the airways. Gln induced the early induction of MAPK phosphatase-1 (MKP-1) protein, a negative regulator of p38. MKP-1 small interfering RNA abrogated all the effects of Gln. Our results suggest that pathways involving p38/cPLA(2)/5-LO have a major role in airway neutrophilia. Gln suppresses airway neutrophilia via inhibiting p38 MAPK and its downstream pathways in an MKP-1-dependent way, which may provide a novel therapeutic strategy for pulmonary neutrophilic inflammatory diseases.

Topics: Animals; Arachidonate 5-Lipoxygenase; Cytosol; Dual Specificity Phosphatase 1; Female; Gene Expression Regulation; Glutamine; Inflammation; Leukotriene B4; Mice; Mice, Inbred BALB C; Neutrophils; p38 Mitogen-Activated Protein Kinases; Phospholipase A2 Inhibitors; Phospholipases A2; Phosphorylation; Respiratory System; Signal Transduction

Antibodies to the pan-leukocyte adhesion-GPCR CD97 efficiently block neutrophil recruitment in mice, thereby reducing antibacterial host defense, inflammatory disease, and hematopoietic stem cell mobilization. Here, we investigated the working mechanism of the CD97 antibody 1B2. Applying sterile models of inflammation, intravital microscopy, and mice deficient for the CD97L CD55, the complement component C3, or the FcR common γ-chain, we show that 1B2 acts in vivo independent of ligand-binding interference by depleting PMN granulocytes in bone marrow and blood. Granulocyte depletion with 1B2 involved FcR but not complement activation and was associated with increased serum levels of TNF and other proinflammatory cytokines. Notably, depletion of granulocytes by CD97 antibody required acute inflammation, suggesting a mechanism of conditional, antibody-mediated granulocytopenia.

Topics: Animals; Antibodies, Blocking; Antibody Specificity; CD55 Antigens; Cell Adhesion; Cell Movement; Cytokines; Granulocytes; Humans; Inflammation; Leukotriene B4; Lipopolysaccharides; Membrane Glycoproteins; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Neutropenia; Peritonitis; Receptors, Fc; Receptors, G-Protein-Coupled; Tumor Necrosis Factor-alpha

We investigated anti-inflammatory properties of a novel 5-lipoxygenase (5-LO) inhibitor, KRH-102140, in vitro and in vivo. 5-LO enzyme activity was assayed using insect cell lysates overexpressing rat 5-LO. The leukotriene B(4) (LTB(4)) level was assayed in rat basophilic leukemia (RBL-1) cell line. ICR (Institute of Cancer Research) mice were used for in vivo assays. Mouse ear edema was induced by topical application of arachidonic acid. An air pouch was induced by subcutaneous injection of sterile air into mice, followed by zymosan treatment. Sprague-Dawley rats were used for pharmacokinetic studies.. KRH-102140 inhibited 5-LO activity with an IC(50) value of 160 ± 23 nmol/l in parallel with LTB(4) inhibition in RBL-1 cells. Oral administration of KRH-102140 (10-100 mg/kg) reduced ear edema, myeloperoxidase activity and LTB(4) production in murine inflammation models. Oral bioavailability as determined in rats was 66%.. Our results show that KRH-102140, a new 5-LO inhibitor, exhibits potent anti-inflammatory activities in vitro as well as in vivo.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonate 5-Lipoxygenase; Benzopyrans; Benzylamines; Cell Line; Drug Discovery; Edema; Half-Life; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Male; Metabolic Clearance Rate; Mice; Mice, Inbred ICR; Peroxidase; Rats; Rats, Sprague-Dawley; Recombinant Proteins

Recent in vitro data have suggested that the flavonoid quercetin (1) does not affect the functioning of neutrophils. Therefore, we evaluated in vivo and in vitro whether or not 1 affects neutrophil function, focusing on recruitment. The in vivo treatment with 1 inhibited in a dose-dependent manner the recruitment of neutrophils to the peritoneal cavity of mice induced by known chemotatic factors such as CXCL1, CXCL5, LTB(4), and fMLP. Furthermore, 1 also inhibited in a concentration-dependent manner the chemoattraction of human neutrophils induced by CXCL8, LTB(4), and fMLP in a Boyden chamber. In vitro treatment with 1 did not affect human neutrophil surface expression of CXCR1, CXCR2, BLT1, or FLPR1, but rather reduced actin polymerization. These results suggest that 1 inhibits actin polymerization, hence, explaining the inhibition of neutrophil recruitment in vivo and in vitro and highlighting its possible usefulness to diminish excessive neutrophil migration during inflammation.

Topics: Actins; Animals; Chemokine CXCL5; Chemotactic Factors; Chemotaxis; Dose-Response Relationship, Drug; Humans; Inflammation; Interleukin-8; Leukotriene B4; Male; Mice; Molecular Structure; N-Formylmethionine Leucyl-Phenylalanine; Neutrophil Infiltration; Neutrophils; Quercetin

We examined whether dietary supplementation with fish oil modulates inflammation, fibrosis and oxidative stress following obstructive renal injury.. Three groups of Sprague-Dawley rats (n=16 per group) were fed for 4 wk on normal rat chow (oleic acid), chow containing fish oil (33 g eicosapentaenoic acid and 26 g docosahexaenoic acid per kg diet), or chow containing safflower oil (60 g linoleic acid per kg diet). All diets contained 7% fat. After 4 wk, the rats were further subdivided into four smaller groups (n=4 per group). Unilateral ureteral obstruction was induced in three groups (for 4, 7 and 14 days). The fourth group for each diet did not undergo surgery, and was sacrificed as controls at 14 days. When rats were sacrificed, plasma and portions of the kidneys were removed and frozen; other portions of kidney tissue were fixed and prepared for histology. Compared with normal chow and safflower oil, fish oil attenuated collagen deposition, macrophage infiltration, TGF-β expression, apoptosis, and tissue levels of arachidonic acid, MIP-1α, IL-1β, MCP-1 and leukotriene B(4). Compared with normal chow, fish oil increased the expression of HO-1 protein in kidney tissue.. Fish oil intake reduced inflammation, fibrosis and oxidative stress following obstructive renal injury.

Topics: Analysis of Variance; Animals; Apoptosis; Arachidonic Acid; Chemokine CCL2; Chemokine CCL3; Collagen; Dietary Fats, Unsaturated; Dietary Supplements; Fibrosis; Fish Oils; Heme Oxygenase-1; Inflammation; Interleukin-1beta; Kidney Diseases; Leukotriene B4; Macrophages; Male; Oxidative Stress; Rats; Rats, Sprague-Dawley; Safflower Oil; Transforming Growth Factor beta

The modulatory activity of dietary n-3 fatty acids on inflammation and immune response in domestic cats is unknown. Mature female cats (n=14/treatment) were fed control, fish oil or flaxseed oil diets with n-6:n-3 fatty acid ratios of 20:1, 5:1 and 5:1, respectively, for 12 wk. Immune response was assessed on wk 0, 6 and 12, and skin hypersensitivity response on wk 6 and 12. Fish oil increased (P<0.01) eicosapentaenoic and docosahexaenoic acids in plasma and skin, whereas flaxseed oil increased α-linolenic acid. Fish and flaxseed oils decreased (P<0.01) skin inflammatory response to histamine. Cats fed fish but not flaxseed oil had higher (P<0.05) skin leukotriene LTB(5), but not LTB(4). Fish and flaxseed oils lowered B, total T and T(h) subset populations, and leukocyte proliferative response to PWM (P<0.05). In contrast, there was no change in ConA- or PHA-induced lymphocyte proliferation, Tc and MHC II cell populations, DTH response, NK cytotoxicity, IL-2 production, or plasma IgG concentrations. Therefore, fish and flaxseed oil can reduce skin inflammatory responses in cats, however, flaxseed oil appears less immunosuppressive than fish oil.

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Cat Diseases; Cats; Diet; Dietary Fats, Unsaturated; Eicosapentaenoic Acid; Female; Fish Oils; Immunosuppressive Agents; Inflammation; Leukotriene B4; Linseed Oil; Lymphocyte Subsets; Pokeweed Mitogens; Skin

Recent advances in lung cancer biology presuppose its inflammatory origin. In this regard, LTB-4 and IL-8 are recognized to play a crucial role in neutrophil recruitment into airways during lung cancer.Notwithstanding the intriguing hypothesis, the exact role of neutrophilic inflammation in tumour biology remains complex and not completely known.The aim of this study was to give our contribution in this field by investigating LTB-4 and IL-8 in the breath condensate of NSCLC patients and verifying their role in cancer development and progression.. We enrolled 50 NSCLC patients and 35 controls. LTB-4 and IL-8 concentrations were measured in the breath condensate and the blood of all the subjects under study using EIA kits. Thirty NSCLC patients and ten controls underwent induced sputum collection and analysis.. LTB-4 and IL-8 resulted higher in breath condensate and the blood of NSCLC patients compared to controls. Significantly higher concentrations were found as the cancer stages progressed. A positive correlation was observed between exhaled IL-8 and LTB-4 and the percentage of neutrophils in the induced sputum.. The high concentrations of exhaled LTB-4 and IL-8 showed the presence of a neutrophilic inflammation in the airways of NSCLC patients and gave a further support to the inflammatory signalling in lung cancer. These exhaled proteins could represent a suitable non-invasive marker in the diagnosis and monitoring of lung cancer.

Topics: Aged; Breath Tests; Carcinoma, Non-Small-Cell Lung; Case-Control Studies; Exhalation; Female; Humans; Inflammation; Interleukin-8; Leukotriene B4; Lung Neoplasms; Male; Middle Aged; Neoplasm Staging; Neutrophil Infiltration; Sputum

The clinical and molecular effects of whole-body polarized light treatment on children suffering from recurrent respiratory infection were studied.. The incidence and duration of respiratory symptoms as well as the length of appropriate antibiotic therapy were measured. Simultaneously, the genome-wide gene expression pattern was examined by whole genome cDNA microarray in peripheral lymphocytes of children.. Twenty of 25 children showed a marked clinical improvement, while in five of 25 had poor response or no changes. The gene expression pattern of the patients' peripheral lymphocytes was compared in favorable and poor responders. The lymphocytes of the children with a documented improved clinical response to polarized light therapy showed a decrease in the expression of chemokine genes, such as CXCL1, CXCL2, CXCL3, and IL-8, and in that of the TNFα gene. On the contrary, a rapid elevation was found in the expression of the gene encoding for CYP4F2, a leukotriene B4-metabolizing enzyme. In children with poor clinical response to polarized light therapy, no similar changes were detected in the gene expression pattern of the lymphocytes.. The improved clinical symptoms and modified gene expression profile of lymphocytes reveals an anti-inflammatory effect of whole-body polarized light irradiation.

Topics: Anti-Inflammatory Agents; Chemokines; Child; Child, Preschool; Female; Gene Expression; Genome-Wide Association Study; Genome, Human; Humans; Infant; Inflammation; Leukotriene B4; Light; Lymphocytes; Male; Oligonucleotide Array Sequence Analysis; Recurrence; Respiration; Respiration Disorders; Respiratory Tract Infections

Aristolochia tagala Cham. (syn: Aristolochia acuminata Lam.) (Aristolochiaceae), known as Nallayishwari in Telugu, has been of interest to researchers because of its traditional uses for treating rheumatic pains and fever.. The anti-inflammatory activity of the petroleum ether, ethyl acetate, and ethanol extracts of A. tagala roots were investigated for the first time.. In vivo and in vitro anti-inflammatory effects were investigated employing the carrageenan-induced hind paw edema in rats and the macrophage cell line RAW264.7 stimulated with proinflammatory stimuli (lipopolysaccharide interferon γ or the calcium ionophore A23187) to determine PGE(2) or LTB(4) release, respectively.. All the extracts exhibited anti-inflammatory effects which were found to be significant (p < 0.001) at 200 and 400 mg/kg, p.o, in rats tested and the ethyl acetate extract inhibited the induction of PGE(2) with IC(50) = 39.1 mg mL(-1) and LTB(4) with IC(50) = 29.5 mg mL(-1).. These findings demonstrate that the A. tagala roots have excellent anti-inflammatory activity and validate the traditional indications of this plant in its origin country.

Topics: Acetates; Alkanes; Animals; Anti-Inflammatory Agents; Aristolochia; Calcimycin; Calcium Ionophores; Carrageenan; Cell Line; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Ethanol; Female; Inflammation; Interferon-gamma; Leukotriene B4; Macrophages; Male; Mice; Plant Extracts; Plant Roots; Plants, Medicinal; Rats; Rats, Wistar; Time Factors

In reconstructive vascular surgery, infection is one of the most feared complications because of the high mortality. While the antimicrobial effect of a silver-coated endoprosthesis has been proven in experimental trials, there are no reports on its interactions with granulocytes, the first effector cells in general inflammation and in infection.. Therefore, we investigated whether silver coating of vascular polyester grafts affects receptor expression, mediator release, and functions of human neutrophils relevant for microbicidal activity and the wound-healing process. Naïve neutrophils were analyzed for their cellular receptors such as cluster of differentiation (CD)62L, CD11b, CXCR2, and fMLP-R, the mediators interleukin 8, granulocyte elastase (human neutrophil elastase), and leukotriene B4 (LTB4) as well as for microbicidal capacity (oxidative burst) in vitro. In addition, the role of plasma coating for receptor expression was addressed.. There was both a decrease of CD62L and CXCR2 expression and an increase of CD11b, fMLP-R expression, elastase release, and LTB4 generation, which were statistically significant (p = 0.04; p = 0.01; p = 0.0; p = 0.0; p = 0.01; p = 0.02, respectively) in the presence of the silver-coated graft compared with non-silver-coated vascular grafts. In addition, microbicidal activity was significantly (p = 0.0) impaired by the silver-coated graft. Coating of the vascular grafts with plasma did not alter the former observations significantly.. The results may indicate that silver-coated vascular polyester grafts activate neutrophils chronically which may favor tissue destruction and impaired antimicrobial effects.

Topics: Blood Vessel Prosthesis; CD11b Antigen; Coated Materials, Biocompatible; Down-Regulation; Flow Cytometry; Humans; Inflammation; Interleukin-8; L-Selectin; Leukocyte Elastase; Leukotriene B4; Neutrophil Activation; Neutrophils; Polyesters; Prosthesis Design; Prosthesis-Related Infections; Receptors, Formyl Peptide; Receptors, Interleukin-8B; Respiratory Burst; Silver Compounds; Up-Regulation; Wound Healing

Herein, we investigated the involvement of the 5-LO-derived lipid mediator LTB(4) in gammadelta T cell migration. When injected into the i.pl. space of C57BL/6 mice, LTB(4) triggered gammadelta T lymphocyte mobilization in vivo, a phenomenon also observed in in vitro chemotaxis assays. The i.pl. injection of Escherichia coli endotoxin (LPS) triggered increased levels of LTB(4) in pleural cavities. The in vivo inhibition of LTB(4) biosynthesis by the 5-LO inhibitor zileuton or the FLAP inhibitor MK886 attenuated LPS-induced gammadelta T cell accumulation into pleural cavities. Accordingly, 5-LO KO mice failed to recruit gammadelta T cells into the inflammatory site after i.pl. LPS. Antagonists of the high-affinity LTB(4) receptor BLT1, CP105,696, and LY292476 also attenuated LPS-induced gammadelta T cell accumulation in pleural cavities as well as in vitro chemotaxis toward pleural washes obtained from LPS-simulated mice. LTB(4)/BLT1 also accounted for gammadelta T cell migration induced by i.pl. administration of Mycobacterium bovis BCG or antigen in sensitized mice. BLT1 was expressed on naïve, resident as well as LPS-recruited gammadelta T cells. Isolated gammadelta T cells were found to undergo F-actin cytoskeleton reorganization when incubated with LTB(4) in vitro, confirming that gammadelta T lymphocytes can respond directly to LTB(4). In addition to its direct effect on gammadelta T cells, LTB(4) triggered their accumulation indirectly, via modulation of CCL2 production in mouse pleural cavities. These data show that gammadelta T cell migration into the pleural cavity of mice during diverse inflammatory responses is dependent on LTB(4)/BLT1.

Topics: Actins; Animals; Arachidonate 5-Lipoxygenase; Benzopyrans; Carboxylic Acids; Cell Movement; Chemokine CCL2; Cytoskeleton; Inflammation; Leukotriene B4; Lipopolysaccharides; Mice; Mice, Knockout; Mycobacterium bovis; Receptors, Antigen, T-Cell, gamma-delta; Receptors, Leukotriene B4; T-Lymphocytes

The purpose of the present study was to determine the effects of dietary antioxidant restriction on plasma concentrations of carotenoids and inflammatory markers at rest and in response to exercise in endurance-trained males. Seventeen males performed two exercise trials 2 weeks apart. Participants followed their habitual antioxidant diet (H-AO) before the first exercise test, then a restricted antioxidant diet (R-AO) for 2 weeks before the second exercise test. Blood was collected pre- and post-exercise. Dietary intakes of fibre, ascorbic acid and beta-carotene were lower (P < 0.05) on the R-AO diet, but no other differences were observed. Pre-exercise plasma beta-carotene concentrations were lower (H-AO, 195 (sd 92); R-AO, 123 (sd 54) ng/ml; P < 0.05), and TNF-alpha concentrations were higher (H-AO, 16 (sd 7); R-AO, 613 (sd 325) pg/ml; P < 0.01) on the R-AO diet compared to the H-AO diet. Most plasma carotenoid concentrations decreased with exercise, but this effect was more consistent on the H-AO diet. No differences in plasma IL-6 concentrations were observed pre-exercise, whereas post-exercise plasma IL-6 concentrations (H-AO, 30.3 (sd 16); R-AO, 15.3 (sd 5) pg/ml; P < 0.05) were lower following the R-AO diet. Post-exercise TNF-alpha concentrations were higher on the R-AO diet. Ratings of perceived effort during submaximal exercise were higher (P < 0.05) on the R-AO diet, but there was no difference in the time to exhaustion between diets. In conclusion, lower dietary intakes of carotenoids alter the plasma concentrations of antioxidants and markers of inflammation at rest and in response to exercise.

Topics: Adolescent; Adult; Antioxidants; Athletes; Blood Specimen Collection; Diet; Exercise Test; Humans; Inflammation; Leukotriene B4; Male; Oxygen Consumption; Running; Young Adult

Animal and clinical studies have suggested that polyphenols in fruits, red wine, and tea may delay the development of atherosclerosis through their antioxidant and anti-inflammatory properties. We investigated whether individual dietary polyphenols representing different polyphenolic classes, namely quercetin (flavonol), (-)-epicatechin (flavan-3-ol), theaflavin (dimeric catechin), sesamin (lignan), or chlorogenic acid (phenolic acid), reduce atherosclerotic lesion formation in the apolipoprotein E (ApoE)(-/-) gene-knockout mouse.. Quercetin and theaflavin (64-mg/kg body mass daily) significantly attenuated atherosclerotic lesion size in the aortic sinus and thoracic aorta (P<0.05 versus ApoE(-/-) control mice). Quercetin significantly reduced aortic F(2)-isoprostane, vascular superoxide, vascular leukotriene B(4), and plasma-sP-selectin concentrations; and augmented vascular endothelial NO synthase activity, heme oxygenase-1 protein, and urinary nitrate excretion (P<0.05 versus control ApoE(-/-) mice). Theaflavin showed similar, although less extensive, significant effects. Although (-)-epicatechin significantly reduced F(2)-isoprostane, superoxide, and endothelin-1 production (P<0.05 versus control ApoE(-/-) mice), it had no significant effect on lesion size. Sesamin and chlorogenic acid treatments exerted no significant effects. Quercetin, but not (-)-epicatechin, significantly increased the expression of heme oxygenase-1 protein in lesions versus ApoE(-/-) controls.. Specific dietary polyphenols, in particular quercetin and theaflavin, may attenuate atherosclerosis in ApoE(-/-) gene-knockout mice by alleviating inflammation, improving NO bioavailability, and inducing heme oxygenase-1. These data suggest that the cardiovascular protection associated with diets rich in fruits, vegetables, and some beverages may in part be the result of flavonoids, such as quercetin.

Topics: Animals; Anti-Inflammatory Agents; Aorta; Aortic Diseases; Apolipoproteins E; Atherosclerosis; Biflavonoids; Biomarkers; Catechin; Chlorogenic Acid; Cholesterol; Diet; Dioxoles; Disease Models, Animal; Endothelin-1; Endothelium, Vascular; F2-Isoprostanes; Fatty Acids; Flavonoids; Heme Oxygenase-1; Inflammation; Leukotriene B4; Lignans; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitrates; Nitric Oxide; Nitric Oxide Synthase Type III; Nitrites; Oxidative Stress; P-Selectin; Phenols; Polyphenols; Quercetin; Superoxides

Previously, we have shown that electroacupuncture (EA) in rats decreased eosinophil infiltration into the pulmonary tissue (PT) and in the bronchoalveolar lavage (BAL) in an experimental model of asthma. Th2 cytokines, leukotriene B4 (LTB4) and nitric oxide (NO) are involved in the asthma inflammatory process. The aim of this study was to verify the effects of EA on these asthma mediators. Male Wistar rats were divided into control (C), immobilized (I), sham acupuncture (SA), and acupuncture (A) groups. All rats were sensitized, and EA treatment using clinical acupuncture points was started 24h after antigen priming. EA was done every other day for 2weeks. Subsequently, animals were challenged by inhalation and sacrificed 24h later. At this time, the BAL and lungs were collected and used to analyze cytokine production, LTB4 and NO. The EA increased IL-1 and IFN-gamma and decreased IL-4, IL-10, NO and LTB4 in the BAL and PT compared to the C and SA groups. The presence of eosinophils in the BAL negatively correlated with IL-1 and IFN-gamma production and positively correlated with IL-4 and IL-10 production. Our results show that the beneficial anti-inflammatory action of EA on asthma is related to the balance of the Thl/Th2 response and the reduction of LTB4 and NO. These results suggest that EA therapy could be an important complementary treatment for asthma.

Topics: Animals; Asthma; Bronchoalveolar Lavage Fluid; Cytokines; Electroacupuncture; Eosinophils; Humans; Inflammation; Leukotriene B4; Male; Nitric Oxide; Rats; Rats, Wistar; T-Lymphocytes, Helper-Inducer; Th1 Cells; Th2 Cells

5-Lipoxygenase (LOX) is an important arachidonic acid-metabolizing enzyme producing leukotrienes and other proinflammatory lipid mediators with potent pathophysiological functions in asthma and other inflammatory diseases. 4-(3-(4-(1-Methyl-1H-pyrazol-5-yl)phenylthio)phenyl)-tetrahydro-2H-pyran-4-carboxamide (PF-4191834) is a novel, selective non-redox 5-lipoxygenase inhibitor effective in inflammation and pain. In vitro and in vivo assays were developed for the evaluation of a novel 5-LOX inhibitor using conditions of maximal enzyme activity. PF-4191834 exhibits good potency in enzyme- and cell-based assays, as well as in a rat model of acute inflammation. Enzyme assay results indicate that PF-4191834 is a potent 5-LOX inhibitor, with an IC(50) = 229 +/- 20 nM. Furthermore, it demonstrated approximately 300-fold selectivity for 5-LOX over 12-LOX and 15-LOX and shows no activity toward the cyclooxygenase enzymes. In addition, PF-4191834 inhibits 5-LOX in human blood cells, with an IC(80) = 370 +/- 20 nM. This inhibitory concentration correlates well with plasma exposures needed for in vivo efficacy in inflammation in models of inflammatory pain. The combination of potency in cells and in vivo, together with a sustained in vivo effect, provides PF-4191834 with an overall pharmacodynamic improvement consistent with once a day dosing.

Topics: Animals; Asthma; Chromatography, Liquid; Disease Models, Animal; Humans; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mass Spectrometry; Oxidation-Reduction; Pain; Pyrazoles; Rats; Rats, Inbred Lew; Rats, Sprague-Dawley; Spectrophotometry; Sulfides

The aim of the present study is to investigate the role of nordihydroguaiaretic acid (NDGA) on inflammatory cells accumulation after focal cerebral ischemia and the underlying mechanism. Focal cerebral ischemia was induced by 30 min of middle cerebral artery occlusion (MCAO) followed by 72 h of reperfusion. NDGA (5 and 10 mg/kg) was administered intraperitoneally 30 min, 2, 24, 48 h after reperfusion, respectively. The brain injuries were observed by neurological and histological examination. Endogenous IgG exudation, neutrophils and macrophages/microglia accumulation, and intercellular adhesion molecule-1 (ICAM-1) protein expression were determined by immunohistochemistry 72 h after reperfusion. ICAM-1 mRNA was determined by RT-PCR 72 h after reperfusion. The catalysates of 5-lipoxygenase (5-LOX), leukotriene B4 (LTB4) and cysteinyl leukotrienes (CysLTs), were evaluated by ELISA 3 h after reperfusion. The results showed that NDGA ameliorated neurological dysfunction, decreased infarct volume, and inhibited endogenous IgG exudation, neutrophils infiltration, ICAM-1 mRNA and protein expression 72 h after reperfusion. Moreover, NDGA reduced the levels of LTB4 and CysLTs 3 h after reperfusion. However, NDGA did not reduce the accumulation of macrophages/microglia 72 h after reperfusion. These results suggest that NDGA decreases neutrophil infiltration in the subacute phase of focal cerebral ischemia via inhibiting 5-LOX activation.

Topics: Animals; Arachidonate 5-Lipoxygenase; Brain Ischemia; Immunoglobulin G; Inflammation; Intercellular Adhesion Molecule-1; Leukotriene B4; Lipoxygenase Inhibitors; Male; Masoprocol; Neutrophils; Rats; Rats, Sprague-Dawley; Reperfusion Injury; RNA, Messenger

Three US applications describing a narrow, closely related series of antagonists of the action of leukotriene B(4) on the BLT1 and BLT2 receptors are described. The generic structure claimed is a lipophilic linked diphenyl core containing two acid groups appended to the central phenyl ring. The terminal phenyl moiety contains disubstitution at the 3'- and 5'-positions. These three applications differ in the nature of the substituent on the terminal phenyl group as well as the linking moiety between the two phenyl rings. These compounds are claimed to have utility in inflammatory diseases such as severe asthma and chronic obstructive pulmonary disease.

Topics: Animals; Humans; Inflammation; Leukotriene Antagonists; Leukotriene B4; Patents as Topic; Receptors, Leukotriene B4

Leukotrienes, the lipid inflammatory products derived from arachidonic acid, are involved in the pathogenesis of respiratory and cardiovascular diseases and reactive airway disease in sickle cell disease. Placenta growth factor (PlGF), elaborated from erythroid cells, increased the mRNA expression of 5-lipoxygenase and 5-lipoxygenase-activating protein (FLAP) in human pulmonary microvascular endothelial cells. PlGF-induced both promoter activity and mRNA expression of hypoxia-inducible factor-1alpha (HIF-1alpha), which was abrogated by early growth response-1 (EGR-1) small interfering RNA. PlGF showed a temporal reciprocal relationship in the mRNA levels of EGR-1 and NAB2, the latter a repressor of Egr-1. Moreover, Nab2, but not mutant Nab2, significantly reduced promoter activity and mRNA expression of HIF-1alpha and also reduced expression of the HIF-1alpha target gene FLAP. Furthermore, overexpression of Egr-1 led to increased promoter activities for both HIF-1alpha and FLAP in the absence of PlGF. Additionally, the Egr-1-mediated induction of HIF-1alpha and FLAP promoters was reduced to basal levels by EGR-1 small interfering RNA. The binding of Egr-1 to HIF-1alpha promoter was corroborated by electrophoretic mobility shift assay and chromatin immunoprecipitation assay, which showed increased Egr-1 binding to the HIF-1alpha promoter in response to PlGF stimulation. These studies provide a novel mechanism for PlGF-mediated regulation of HIF-1alpha via Egr-1, which results in increased FLAP expression. This study provides a new therapeutic target, namely Egr-1, for attenuation of elevated leukotriene levels in patients with sickle cell disease and other inflammatory diseases.

Topics: Anemia, Sickle Cell; DNA, Single-Stranded; Female; Gene Expression Regulation; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Inflammation; Leukotriene B4; Leukotrienes; Lipopolysaccharides; Placenta Growth Factor; Pregnancy; Pregnancy Proteins; Promoter Regions, Genetic; RNA, Messenger; RNA, Small Interfering; Tumor Necrosis Factor-alpha

We evaluated the in vivo pharmacological properties of AM803 3-[3-tert-butylsulfanyl-1-[4-(6-ethoxy-pyridin-3-yl)-benzyl]-5-(5-methyl-pyridin-2-ylmethoxy)-1H-indol-2-yl]-2,2-dimethyl-propionic acid, a selective five-lipoxygenase-activating protein (FLAP) inhibitor, using rat and mouse models of acute inflammation. Oral administration of AM803 (1 mg/kg) resulted in sustained inhibition of ex vivo ionophore-challenged whole blood LTB4 biosynthesis with >90% inhibition for up to 12 h and an EC50 of approximately 7 nM. When rat lungs were challenged in vivo with calcium-ionophore, AM803 inhibited LTB4 and cysteinyl leukotriene (CysLT) production with ED50s of 0.12 mg/kg and 0.37 mg/kg, respectively. The inhibition measured 16 h following a single oral dose of 3 mg/kg was 86% and 41% for LTB4 and CysLTs, respectively. In an acute inflammation setting, AM803 dose-dependently reduced LTB4, CysLTs, plasma protein extravasation and neutrophil influx induced by peritoneal zymosan injection. Finally, AM803 increased survival time in mice exposed to a lethal intravenous injection of platelet activating factor (PAF). The magnitude of effect was similar to that of an inhibitor of five-lipoxygenase (5-LO) and LTA4 hydrolase but superior to a leukotriene CysLT1 receptor antagonist. In summary, AM803 is a novel, potent and selective FLAP inhibitor that has excellent pharmacodynamic properties in vivo and is effective in animal models of acute inflammation and in a model of lethal shock.

Topics: 5-Lipoxygenase-Activating Proteins; Animals; Carrier Proteins; Chronic Disease; Cysteine; Disease Models, Animal; Female; Humans; Indoles; Inflammation; Leukotriene B4; Leukotrienes; Lung; Male; Membrane Proteins; Mice; Pentanoic Acids; Platelet Activating Factor; Propionates; Rats; Substrate Specificity; Zymosan

Leukotriene A(4) hydrolase (LTA(4)H) is a proinflammatory enzyme that generates the inflammatory mediator leukotriene B(4) (LTB(4)). LTA(4)H also possesses aminopeptidase activity with unknown substrate and physiological importance; we identified the neutrophil chemoattractant proline-glycine-proline (PGP) as this physiological substrate. PGP is a biomarker for chronic obstructive pulmonary disease (COPD) and is implicated in neutrophil persistence in the lung. In acute neutrophil-driven inflammation, PGP was degraded by LTA(4)H, which facilitated the resolution of inflammation. In contrast, cigarette smoke, a major risk factor for the development of COPD, selectively inhibited LTA(4)H aminopeptidase activity, which led to the accumulation of PGP and neutrophils. These studies imply that therapeutic strategies inhibiting LTA(4)H to prevent LTB(4) generation may not reduce neutrophil recruitment because of elevated levels of PGP.

Topics: Acetylation; Animals; Bronchoalveolar Lavage Fluid; Cells, Cultured; Chemokines, CXC; Chemotaxis, Leukocyte; Epoxide Hydrolases; Female; Humans; Inflammation; Leukotriene B4; Lung; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Neutrophils; Nicotiana; Oligopeptides; Orthomyxoviridae Infections; Pneumococcal Infections; Pneumonia; Proline; Pulmonary Disease, Chronic Obstructive; Smoke

Hepatocyte nuclear factor 4α (HNF4α) is a nuclear transcription factor mainly expressed in the liver, intestine, kidney, and pancreas. Many of its hepatic and pancreatic functions have been described, but limited information is available on its role in the gastrointestinal tract. The objectives of this study were to evaluate the anti-inflammatory and antioxidant functions of HNF4α as well as its implication in intestinal lipid transport and metabolism. To this end, the HNF4A gene was knocked down by transfecting Caco-2 cells with a pGFP-V-RS lentiviral vector containing an shRNA against HNF4α. Inactivation of HNF4α in Caco-2 cells resulted in the following: (a) an increase in oxidative stress as demonstrated by the levels of malondialdehyde and conjugated dienes; (b) a reduction in secondary endogenous antioxidants (catalase, glutathione peroxidase, and heme oxygenase-1); (c) a lower protein expression of nuclear factor erythroid 2-related factor that controls the antioxidant response elements-regulated antioxidant enzymes; (d) an accentuation of cellular inflammatory activation as shown by levels of nuclear factor-κB, interleukin-6, interleukin-8, and leukotriene B4; (e) a decrease in the output of high density lipoproteins and of their anti-inflammatory and anti-oxidative components apolipoproteins (apo) A-I and A-IV; (f) a diminution in cellular lipid transport revealed by a lower cellular secretion of chylomicrons and their apoB-48 moiety; and (g) alterations in the transcription factors sterol regulatory element-binding protein 2, peroxisome proliferator-activated receptor α, and liver X receptor α and β. In conclusion, HNF4α appears to play a key role in intestinal lipid metabolism as well as intestinal anti-oxidative and anti-inflammatory defense mechanisms.

Topics: Antioxidants; Biological Transport; Caco-2 Cells; Epithelial Cells; Gene Knockdown Techniques; Hepatocyte Nuclear Factor 4; Humans; Inflammation; Interleukin-6; Interleukin-8; Intestinal Mucosa; Leukotriene B4; Lipid Metabolism; Lipoproteins; Liver X Receptors; Malondialdehyde; Orphan Nuclear Receptors; Oxidative Stress; Oxidoreductases; PPAR alpha; Sterol Regulatory Element Binding Protein 2

Mechanisms by which mesenchymal-derived tissue lineages participate in amplifying and perpetuating synovial inflammation in arthritis have been relatively underinvestigated and are therefore poorly understood. Elucidating these processes is likely to provide new insights into the pathogenesis of multiple diseases. Leukotriene B(4) (LTB(4)) is a potent proinflammatory lipid mediator that initiates and amplifies synovial inflammation in the K/BxN model of arthritis. We sought to elucidate mechanisms by which mesenchymal-derived fibroblast-like synoviocytes (FLSs) perpetuate synovial inflammation. We focused on the abilities of FLSs to contribute to LTB(4) synthesis and to respond to LTB(4) within the joint. Using a series of bone marrow chimeras generated from 5-lipoxygenase(-/-) and leukotriene A(4) (LTA(4)) hydrolase(-/-) mice, we demonstrate that FLSs generate sufficient levels of LTB(4) production through transcellular metabolism in K/BxN serum-induced arthritis to drive inflammatory arthritis. FLSs-which comprise the predominant lineage populating the synovial lining-are competent to metabolize exogenous LTA(4) into LTB(4) ex vivo. Stimulation of FLSs with TNF increased their capacity to generate LTB(4) 3-fold without inducing the expression of LTA(4) hydrolase protein. Moreover, LTB(4) (acting via LTB(4) receptor 1) was found to modulate the migratory and invasive activity of FLSs in vitro and also promote joint erosion by pannus tissue in vivo. Our results identify novel roles for FLSs and LTB(4) in joints, placing LTB(4) regulation of FLS biology at the center of a previously unrecognized amplification loop for synovial inflammation and tissue pathology.

Topics: Animals; Arthritis, Experimental; Blotting, Western; Enzyme-Linked Immunosorbent Assay; Fibroblasts; Fluorescent Antibody Technique; Inflammation; Leukotriene B4; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Synovial Membrane

Topics: Acetylation; Animals; Chemokines, CXC; Chemotaxis, Leukocyte; Epoxide Hydrolases; Humans; Inflammation; Leukotriene B4; Lung; Mice; Neutrophil Activation; Neutrophils; Nicotiana; Oligopeptides; Orthomyxoviridae Infections; Pneumococcal Infections; Pneumonia; Proline; Pulmonary Disease, Chronic Obstructive; Smoke

Epidemiological evidence for the role of polyunsaturated fatty-acids (PUFA) in Crohn's disease (CD) is unclear, although the key metabolite leucotriene B4 (LTB(4)) is closely linked to the inflammatory process. We hypothesized that inherited variation in key PUFA metabolic enzymes may modify susceptibility for CD.. A case-control design was implemented at three pediatric gastroenterology clinics in Canada. Children ≤20 yrs diagnosed with CD and controls were recruited. 19 single nucleotide polymorphisms (SNPs) across the ALOX5 (4) CYP4F3 (5) and CYP4F2 (10) genes, were genotyped. Associations between SNPs/haplotypes and CD were examined. A total of 431 cases and 507 controls were studied. The mean (±SD) age of the cases was 12.4 (±3.3) years. Most cases were male (56.4%), had ileo-colonic disease (L3±L4, 52.7%) and inflammatory behavior (B1±p, 87%) at diagnosis. One genotyped CYP4F3 SNP (rs2683037) not in Hardy-Weinberg Equilibrium was excluded. No associations with the remaining 4 CYP4F3 SNPs with CD were evident. However haplotype analysis revealed associations with a two-marker haplotype (TG) (rs3794987 & rs1290617) (p = 0.02; permuted p = 0.08). CYP4F2 SNPs, rs3093158 (OR (recessive) = 0.56, 95% CI = 0.35-0.89; p = 0.01), rs2074902 (OR (trend) = 1.26, 95% CI = 1.00-1.60; p = 0.05), and rs2108622 (OR (recessive) = 1.6, 95% CI = 1.00-2.57; p = 0.05) were significantly associated whereas rs1272 (OR (recessive) = 0.58, 95% CI = 0.30-1.13; p = 0.10) showed suggestions for associations with CD. A haplotype comprising these 4 SNPs was significantly associated (p = 0.007, permuted p = 0.02) with CD. Associations with SNP rs3780901 in the ALOX5 gene were borderline non-significant (OR (dominant) = 1.29, 95% CI = 0.99-1.67; p = 0.056). A haplotype comprising the 4 ALOX5 SNPs (TCAA, p = 0.036) was associated with CD, but did not withstand corrections for multiple comparisons (permuted p = 0.14).. Inherited variation in enzymes involved in the synthesis/metabolism of LTB(4) may be associated with CD. These findings implicate PUFA metabolism as a important pathway in the CD pathogenesis.

Topics: Adolescent; Adult; Canada; Case-Control Studies; Child; Child, Preschool; Crohn Disease; Fatty Acids, Unsaturated; Female; Genetic Variation; Haplotypes; Humans; Inflammation; Leukotriene B4; Male; Polymorphism, Single Nucleotide

Previous studies have shown that leukotriene B4 (LTB4), a proinflammatory lipid mediator, is linked to the development of airway hyperresponsiveness through the accumulation of IL-13-producing CD8+ T cells, which express a high affinity receptor for LTB4, BLT1 (Miyahara et al., Am J Respir Crit Care Med 2005;172:161-167; J Immunol 2005;174:4979-4984). By using leukotriene A4 hydrolase-deficient (LTA4H-/-) mice, which fail to synthesize LTB4, we determined the role of this lipid mediator in allergen-induced airway responses. Two approaches were used. In the first, LTA4H-/- mice and wild-type (LTA4H+/+) mice were systemically sensitized and challenged via the airways to ovalbumin. In the second, mice were passively sensitized with anti-ovalbumin IgE and exposed to ovalbumin via the airways. Mast cells were generated from bone marrow of LTA4H+/+ mice or LTA4H-/- mice. After active sensitization and challenge, LTA4H-/- mice showed significantly lower airway hyperresponsiveness compared with LTA4H+/+ mice, and eosinophil numbers and IL-13 levels in the bronchoalveoloar lavage of LTA4H-/- mice were also significantly lower. LTA4H-/- mice also showed decreased airway reactivity after passive sensitization and challenge. After LTA4H+/+ mast cell transfer, LTA4H-/- mice showed increased airway reactivity after passive sensitization and challenge, but not after systemic sensitization and challenge. These data confirm the important role for LTB4 in the development of altered airway responses and suggest that LTB4 secretion from mast cells is critical to eliciting increased airway reactivity after passive sensitization with allergen-specific IgE.

Topics: Allergens; Animals; Bone Marrow Cells; Bronchial Hyperreactivity; CD8-Positive T-Lymphocytes; Cytokines; Female; Immunoglobulin E; Inflammation; Interleukin-13; Leukotriene B4; Lipids; Mast Cells; Mice; Mice, Transgenic

The purpose of the study was to determine which of the active constituents of fish oil, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), is most effective in suppressing proinflammatory mediator generation and cytokine expression from LPS-stimulated human asthmatic alveolar macrophages (AMphi).. The AMphi were obtained from twenty-one asthmatic adults using fiberoptic bronchoscopy. Cells were pretreated with DMEM, pure EPA, an EPA-rich media (45% EPA/10% DHA), pure DHA, a DHA-rich media (10% EPA/50% DHA) or Lipovenos (n-6 PUFA), and then exposed to Dulbecco's Modified Eagle's Medium (DMEM) (-) or LPS (+). Supernatants were analyzed for leukotriene (LT)B(4), prostaglandin (PG)D(2), tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta production. Detection of TNF-alpha and IL-1beta mRNA expression levels was quantified by reverse transcriptase polymerase chain reaction.. 120 microM pure EPA and EPA-rich media significantly (p<0.05) suppressed TNF-alpha and IL-1beta mRNA expression and the production of LTB(4), PGD(2) and TNF-alpha and IL-1beta in LPS-stimulated primary AMphi cells obtained from asthmatic patients to a much greater extent than 120 microM pure DHA and DHA-rich media respectively.. This study has shown for the first time that EPA is a more potent inhibitor than DHA of inflammatory responses in human asthmatic AMphi cells.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Asthma; Cell Line; Docosahexaenoic Acids; Dose-Response Relationship, Drug; Eicosapentaenoic Acid; Humans; Inflammation; Interleukin-1beta; Leukotriene B4; Lipopolysaccharides; Macrophages, Alveolar; Prostaglandin D2; Reverse Transcriptase Polymerase Chain Reaction; Tumor Necrosis Factor-alpha

Equine laminar tissues do not contain resident neutrophils and have less superoxide dismutase (SOD) activity than other equine tissues, which makes them inherently more vulnerable to damage induced by reactive oxygen species (ROS) produced by neutrophils that enter the tissues. In the advanced clinical stages of acute laminitis, pathologic events in affected feet include a breakdown in the basement membrane, neutrophil infiltration, and platelet-neutrophil aggregates in laminar dermal veins, highlighting the contribution of neutrophils to the pathophysiology of the disease. The aim of this study was to determine the role of p38 MAPK in the mechanism underlying equine neutrophil migration to potentially reveal therapeutic targets that may limit lamellar damage from the neutrophil influx that occurs in acute laminitis. We determined that the endogenous chemoattractant LTB(4) transiently activated p38 MAPK and induced chemotaxis of equine primary neutrophils. Inhibition with the p38 MAPK specific inhibitor SB203580 reduced LTB(4)-induced migration in a dose-dependent manner with an IC(50) of 2.8 microM. We then examined the potential mechanisms underlying the ability of SB203580 to abolish migration. We determined that inhibition of p38 MAPK with 10 microM SB203580 disrupted the ability of neutrophils to polarize in response to LTB(4) and PAF. In contrast, p38 MAPK did not appear to be required for chemoattractant- or PKC-induced beta2 integrin-dependent adhesion or chemoattractant-induced upregulation of surface beta2 integrins, but was required for TNFalpha-induced adhesion. These findings support a function for p38 MAPK in equine neutrophil migration and suggest the potential for the ability of p38 MAPK inhibition to limit neutrophilic inflammation in the laminae during acute laminitis.

Topics: Animals; CD18 Antigens; Cell Adhesion; Cells, Cultured; Chemotaxis, Leukocyte; Dose-Response Relationship, Drug; Enzyme Inhibitors; Gene Expression Regulation; Horses; Imidazoles; Inflammation; Leukotriene B4; Neutrophils; p38 Mitogen-Activated Protein Kinases; Pyridines

Ligation of the leukotriene B(4) (LTB(4)) receptor 1 on effector memory CD8(+) T cells by LTB(4) is important for the recruitment of CD8(+) T cells into the airways, which appears central to the induction of airway hyperresponsiveness (AHR) and allergic inflammation. Phosphorylation of extracellular signal-regulated kinase (ERK) is important in activation and cytokine production from many cell types.. The roles of ERKs in effector CD8(+) T-cell function and on CD8(+) T cell-mediated AHR were determined.. Effector CD8(+) T cells were generated from OVA(257-264) (SIINFEKL) peptide-primed mononuclear cells from OT-1 mice. The effects of U0126, an ERK inhibitor, on effector CD8(+) T-cell function and on CD8(+) T cell-mediated AHR and allergic inflammation were examined.. Pretreatment of effector CD8(+) T cells with U0126 suppressed anti-CD3/anti-CD28-induced ERK1/2 phosphorylation and cytokine production, but did not affect LTB(4)-induced Ca(2+) mobilization or chemotaxis. Adoptive transfer of U0126-treated CD8(+) T cells into sensitized mice before secondary allergen challenge resulted in significant decreases in AHR, eosinophilic inflammation, goblet cell metaplasia, and IL-5 and IL-13 levels in bronchoalveolar lavage fluid of recipient mice. The number of transferred CD8(+) T cells accumulating in bronchoalveolar lavage fluid or lungs was unaffected by treatment.. ERK1/2-dependent pathways are essential for the effector functions of CD8(+) T cells, including T(H)2 cytokine production, allergic inflammation, and development of AHR. Inhibition of ERK1/2 signaling has potential therapeutic benefit in preventing CD8(+) T cell-mediated AHR.

Topics: Adoptive Transfer; Allergens; Animals; Bronchoalveolar Lavage Fluid; Butadienes; Calcium; CD8-Positive T-Lymphocytes; Chemotaxis; Enzyme Inhibitors; Eosinophils; Goblet Cells; Immunologic Memory; Inflammation; Leukotriene B4; Lung; MAP Kinase Signaling System; Metaplasia; Mice; Mice, Transgenic; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Nitriles; Receptors, Leukotriene B4; Respiratory Hypersensitivity; Th2 Cells

We investigated the effects of a gamma-tocopherol-rich mixture of tocopherols (gamma-TmT, containing 57% gamma-T, 24% delta-T, and 13% alpha-T) on colon carcinogenesis in azoxymethane (AOM)/dextran sulfate sodium (DSS)-treated mice. In experiment 1, 6-week-old male CF-1 mice were given a dose of AOM (10 mg/kg body weight, i.p.), and 1 week later, 1.5% DSS in drinking water for 1 week. The mice were maintained on either a gamma-TmT (0.3%)-enriched or a standard AIN93M diet, starting 1 week before the AOM injection, until the termination of experiment. In the AOM/DSS-treated mice, dietary gamma-TmT treatment resulted in a significantly lower colon inflammation index (52% of the control) on day 7 and number of colon adenomas (9% of the control) on week 7. gamma-TmT treatment also resulted in higher apoptotic index in adenomas, lower prostaglandin E2, leukotriene B4, and nitrotyrosine levels in the colon, and lower prostaglandin E2, leukotriene B4, and 8-isoprostane levels in the plasma on week 7. Some of the decreases were observed even on day 7. In experiment 2 with AOM/DSS- treated mice sacrificed on week 21, dietary 0.17% or 0.3% gamma-TmT treatment, starting 1 week before the AOM injection, significantly inhibited adenocarcinoma and adenoma formation in the colon (to 17-33% of the control). Dietary 0.3% gamma-TmT that was initiated after DSS treatment also exhibited a similar inhibitory activity. The present study showed that gamma-TmT effectively inhibited colon carcinogenesis in AOM/DSS-treated mice, and the inhibition may be due to the apoptosis-inducing, anti-inflammatory, antioxidative, and reactive nitrogen species-trapping activities of tocopherols.

Topics: Adenocarcinoma; Adenoma; Animals; Antioxidants; Apoptosis; Azoxymethane; Carcinogens; Cell Transformation, Neoplastic; Cocarcinogenesis; Colon; Colonic Neoplasms; Dextran Sulfate; Dinoprost; Dinoprostone; Dose-Response Relationship, Drug; gamma-Tocopherol; Inflammation; Leukotriene B4; Male; Mice; Tyrosine

Accumulating evidence confirms the presence of pan-airway inflammation in allergic rhinitis patients. Smoking is known to affect the asthmatic airway inflammation. However, no study has evaluated the impact of smoking on airway inflammation of allergic rhinitis patients.. The aim of the present study was to evaluate the impact of smoking on inflammatory and oxidative stress biomarkers in patients with seasonal allergic rhinitis, using non-invasive methods for sample collection.. Forty patients with seasonal allergic rhinitis (20 smokers and 20 non-smokers) and 30 healthy subjects (15 smokers and 15 non-smokers) were recruited for the study during pollen season. All subjects were submitted to measurement of the fraction of exhaled NO (FeNO), exhaled breath condensate (EBC) collection, nasal lavage collection, pre- and post- bronchodilation spirometry and metacholine bronchial challenge testing. pH, leukotriene B(4) (LTB(4)) and 8-isoprostane were determined in EBC and nasal lavage samples.. Patients with allergic rhinitis presented higher LTB(4) and 8-isoprostane levels in nasal lavage (P<0.0001 for both comparisons), with no significant differences between smokers and non-smokers. Patients with allergic rhinitis also presented higher LTB(4) levels and lower pH in EBC (P<0.001 and P=0.004, respectively), with prominent differences between smokers and non-smokers (P<0.0001 and P=0.003, for LTB(4) and pH, respectively). A significant correlation between nasal lavage and EBC LTB(4) values was observed (r(s)=0.313, P=0.048).. Patients with allergic rhinitis present increased LTB(4) and 8-isoprostane in their nasal cavity, however, with no significant differences between smokers and non-smokers. In contrast, smokers with allergic rhinitis present higher LTB(4) levels and lower pH in EBC, suggesting that these patients may be more susceptible to the deleterious effects of smoking, compared with non-smokers.

Topics: Adult; Biomarkers; Breath Tests; Dinoprost; Eosinophils; Female; Humans; Hydrogen-Ion Concentration; Immunoglobulin E; Inflammation; Leukotriene B4; Male; Nasal Lavage Fluid; Nitric Oxide; Oxidative Stress; Rhinitis, Allergic, Seasonal; Smoking

Over the past 100 years, changes in the food supply in Western nations have resulted in alterations in dietary fatty acid consumption, leading to a dramatic increase in the ratio of omega-6 (omega6) to omega3 polyunsaturated fatty acids (PUFA) in circulation and in tissues. Increased omega6/omega3 ratios are hypothesized to increase inflammatory mediator production, leading to higher incidence of inflammatory diseases, and may impact inflammatory gene expression. To determine the effect of reducing the omega6/omega3 ratio on expression of inflammatory pathway genes in mononuclear cells, healthy humans were placed on a controlled diet for 1 week, then given fish oil and borage oil for an additional 4 weeks. Serum and neutrophil fatty acid composition and ex vivo leukotriene B(4) production from stimulated neutrophils were measured at the start and end of the supplementation period and after a 2-week washout. RNA was isolated from mononuclear cells and expression of PI3K, Akt, NFkappaB, and inflammatory cytokines was measured by real-time PCR. A marked increase was seen in serum and neutrophil levels of long-chain omega3 PUFA concomitant with a reduction in the omega6/omega3 PUFA ratio (40%). The ex vivo capacity of stimulated neutrophils to produce leukotriene B(4) was decreased by 31%. Expression of PI3Kalpha and PI3Kgamma and the quantity of PI3Kalpha protein in mononuclear cells was reduced after supplementation, as was the expression of several proinflammatory cytokines. These data reveal that PUFA may exert their clinical effects via their capacity to regulate the expression of signal transduction genes and genes for proinflammatory cytokines.

Topics: Dietary Fats; Dietary Fats, Unsaturated; Fatty Acids; Fatty Acids, Omega-3; Fish Oils; gamma-Linolenic Acid; Gene Expression Regulation; Humans; Inflammation; Kinetics; Leukocytes, Mononuclear; Leukotriene B4; Neutrophils; Phosphatidylinositol 3-Kinases; Plant Oils; Reverse Transcriptase Polymerase Chain Reaction; RNA

Recent data suggest that ultrafine pollutant particles (diameter <0.1microm) may pass from the lung into the systemic circulation. However, the systemic and cardiorespiratory effects of translocated particles are not well known. In this study, we determined the direct acute (24h) effect of the systemic administration of 0.01mg/kg and 0.02mg/kg diesel exhaust particles (DEP) on systolic blood pressure, heart rate, and both systemic and pulmonary inflammation in spontaneously hypertensive rats (SHR). Compared to the blood pressure in control group, rats exposed to DEP exhibited a dose-dependent increase in systolic blood pressure, at 0.01mg/kg (P<0.05) and 0.02mg/kg (P<0.01). Likewise, the heart rate was also dose-dependently increased at 0.01mg/kg (P:NS) and 0.02mg/kg (P<0.01) compared to control SHR. DEP exposure (0.02mg/kg) significantly elevated the number of leukocytes in blood (P<0.05), interleukin-6 (IL-6, P<0.005), tumor necrosis factor alpha (P<0.05) and leukotriene B4 (LTB4, P<0.005) concentrations in plasma. Moreover, in SHR given 0.02mg/kg, the number of platelet was significantly reduced (P<0.05), whereas the tail bleeding time was prolonged (P<0.05). Pulmonary inflammations were confirmed by the presence of a significant increase in the number of macrophages (0.02mg/kg) and neutrophils (0.01 and 0.02mg/kg) and protein contents (0.02mg/kg) in bronchoalveolar lavage (BAL) compared to saline-treated SHR. Also, IL-6 (0.01mg/kg; P<0.05 and 0.02mg/kg; P<0.01), LTB4 (0.02mg/kg; P<0.05) concentrations in BAL and the superoxide dismutase activity (0.02mg/kg; P=0.01) were significantly elevated compared to control group. We conclude that, in SHR, the presence of DEP in the systemic circulation leads not only to cardiac and systemic changes, but also triggers pulmonary inflammatory reaction involving IL-6, LTB4 and oxidative stress.

Topics: Air Pollutants; Animals; Blood Platelets; Blood Pressure; Dose-Response Relationship, Drug; Heart Rate; Inflammation; Inhalation Exposure; Interleukin-6; Leukocytes; Leukotriene B4; Lung; Male; Oxidative Stress; Particle Size; Rats; Rats, Inbred SHR; Vehicle Emissions

Histoplasmosis is a pulmonary disease characterised by chronic granulomatous and suppurative inflammatory reactions caused by Histoplasma capsulatum. Regarding new therapies to control fungal infections, the aim of this study was to investigate whether pulmonary administration of leukotriene B(4) (LTB(4))-loaded microspheres (MS) could confer protection to 5-lipoxygenase knockout (5-LO(-/-)) mice infected by H. capsulatum. In this study, MS containing LTB(4) were administered intranasally to mice infected by H. capsulatum. On Day 14 after the infection, fungal recovery from the lungs and histology were evaluated and inflammatory cytokines were measured. Pulmonary administration of LTB(4)-loaded MS was able to reduce fungal recovery from infected lungs. Production of important inflammatory cytokines related to host defence was augmented following MS administration to the lungs. Lung histology also showed that infected mice presented a clear reduction in the fungal burden following the pulmonary release of LTB(4) from MS. Our study provides evidence that the proposed biodegradable microparticulate system, which can release LTB(4) to the lungs, can be employed as therapy, enhancing the antimicrobial activity of host cells during histoplasmosis.

Topics: Administration, Intranasal; Animals; Cytokines; Glycolates; Histoplasma; Histoplasmosis; Humans; Inflammation; Lactic Acid; Leukotriene B4; Lipoxygenase; Lung; Lung Diseases, Fungal; Male; Mice; Mice, Knockout; Microspheres; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Treatment Outcome

In a previous study, we reported a new gamma-hydroxybutenolide derivative, 4-benzo[b]thiophen-2-yl-3-bromo-5-hydroxy-5H-furan-2-one (BTH), as inhibitor of microsomal prostaglandin E synthase-1 (mPGES-1) expression in lypopolysaccharide (LPS) stimulated RAW 264.7 and TPH-1 cells, without affecting cyclooxygenase-2 (COX-2). In this study, we evaluated the in vivo effect of BTH on some acute and chronic inflammatory animal models in relation to its inhibitory profile on mPGES-1 expression. In the zymosan-induced mouse air pouch model, BTH produced a dose-dependent inhibition of prostaglandin E(2) (PGE(2)) production and mPGES-1 protein expression in pouch exudates without any effect on COX-2 protein expression. This behavior was confirmed in the chronic model of collagen-induced arthritis, where administration of BTH (5 mg/kg) clearly reduced PGE(2) and mPGES-1 expression in joint tissues, whereas COX-2 was unaffected. These effects were accompanied by the suppression of clinical and histopathological manifestations of disease such as the loss of proteoglycan, and the destruction of surface cartilage. Other enzymes participating in the metabolism of arachidonic acid, such as prostaglandin I(2) synthase, tromboxane A(2) synthase or 5-lipoxygenase were unaffected by this compound. The acetic acid-induced hyperalgesia model in LPS-sensitized mice showed a dose-dependent analgesic effect of BTH, exerting an ED(50) value of 6.2 mg/kg. Our data suggest that inhibition of mPGES-1 protein expression in acute and chronic inflammatory models by BTH, could provide a potential therapeutic target and a pharmacological tool to discern the role of the inducible enzymes COX-2 and mPGES-1 in inflammatory pathologies.

Topics: 4-Butyrolactone; Acetates; Analgesics; Animals; Anti-Inflammatory Agents; Arthritis, Experimental; Behavior, Animal; Blood Platelets; Cattle; Chronic Disease; Gene Expression Regulation, Enzymologic; Humans; Hyperalgesia; Inflammation; Intramolecular Oxidoreductases; Leukotriene B4; Male; Mice; Neutrophils; Prostaglandin-E Synthases; Thiophenes; Thromboxane B2

Chronic inflammation has long been associated with neoplastic progression. Our group had recently shown that the addition of a large number of apoptotic tumor cells to the tumor microenvironment induces a potent acute inflammatory reaction capable of promoting melanoma growth; however, primarily necrotizing cells do not cause such a reaction. Here, we show that potent inflammatory agents, such as lipopolysaccharide (LPS) and carrageenan, also promote growth of subtumorigenic doses of melanoma cells, having no effect on melanoma proliferation in vitro. Inhibition of 5-lipoxygenase (5-LOX) seems to have a pivotal role in this model because caffeic acid and MK886, a FLAP (5-LOX-activating protein) inhibitor, partially hindered tumor growth induced by apoptotic cells or LPS. Other enzymes of the arachidonic acid pathway, cyclooxygenase-1 and cyclooxygenase-2, seem to have no participation in this tumor promoter effect, as the inhibitor of both enzymes (indomethacin) did not alter melanoma growth. Leukotriene B4 (LTB4), the main product of the 5-LOX pathway, was able to induce growth of subtumorigenic inocula of melanoma cells, and a LTB4 receptor antagonist inhibited acute inflammation-associated tumor growth. Addition to the tumor inflammatory microenvironment of eicosapentaenoic acid, an omega3-polyunsaturated fatty acid with anti-inflammatory properties, or leukotriene B5, an eicosapentaenoic acid-derived leukotriene, significantly inhibited tumor development. These results give new insights to the mechanisms through which inflammation may contribute to tumor progression and suggest that LOX has an important role in tumor progression associated with an inflammatory state in the presence of apoptosis, which may be a consideration for apoptosis-inducing treatments, such as chemotherapy and radiotherapy.

Topics: Animals; Apoptosis; Arachidonate 5-Lipoxygenase; Carrageenan; Cell Growth Processes; Cell Line, Tumor; Disease Progression; Eicosapentaenoic Acid; Histocytochemistry; Indomethacin; Inflammation; Leukotriene B4; Lipopolysaccharides; Lipoxygenase Inhibitors; Melanoma; Mice; Prostaglandin-Endoperoxide Synthases

Leukotrienes (LTs) are proinflammatory lipid mediators synthesized by the conversion of arachidonic acid (AA) to LTA(4) by the enzyme 5-lipoxygenase (5-LO) in the presence of 5-LO-activating protein (FLAP). 3-[3-tert-Butylsulfanyl-1-[4-(6-methoxy-pyridin-3-yl)-benzyl]-5-(pyridin-2-ylmethoxy)-1H-indol-2-yl]-2,2-dimethyl-propionic acid (AM103) is a novel selective FLAP inhibitor in development for the treatment of respiratory conditions such as asthma. In a rat ex vivo whole-blood calcium ionophore-induced LTB(4) assay, AM103 (administered orally at 1 mg/kg) displayed >50% inhibition for up to 6 h with a calculated EC(50) of approximately 60 nM. When rat lung was challenged in vivo with calcium ionophore, AM103 inhibited LTB(4) and cysteinyl leukotriene (CysLT) production with ED(50) values of 0.8 and 1 mg/kg, respectively. In this model, the EC(50) derived from plasma AM103 was approximately 330 nM for inhibition of both LTB(4) and CysLT. In an acute inflammation setting, AM103 displayed dose-dependent inhibition of LTB(4), CysLT, and plasma protein extravasation induced by peritoneal zymosan injection. In a model of chronic lung inflammation using ovalbumin-primed and challenged BALB/c mice, AM103 reduced the concentrations of eosinophil peroxidase, CysLTs, and interleukin-5 in the bronchoalveolar lavage fluid. Finally, AM103 increased survival time in mice exposed to a lethal intravenous injection of platelet-activating factor. In summary, AM103 is a novel, potent and selective FLAP inhibitor that has excellent pharmacodynamic properties in vivo and is effective in animal models of acute and chronic inflammation and in a model of lethal shock.

Topics: 5-Lipoxygenase-Activating Proteins; Acute Disease; Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Asthma; Carrier Proteins; Chronic Disease; Disease Models, Animal; Dose-Response Relationship, Drug; Extravasation of Diagnostic and Therapeutic Materials; Female; Humans; Indoles; Inflammation; Leukotriene B4; Male; Membrane Proteins; Mice; Mice, Inbred BALB C; Pneumonia; Propionates; Rats; Rats, Sprague-Dawley; Zymosan

Huang-Lian-Jie-Du-Tang (HLJDT) is a traditional Chinese medicine with a long history of anti-inflammatory use, but its pharmacological effects have not been thoroughly investigated. This study aimed to evaluate the anti-inflammatory activity of HLJDT in vivo and in vitro.. The carrageenan rat air pouch model was used to investigate the anti-inflammatory action of HLJDT after oral administration. Moreover, we exploited a modified method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique to assay the effects of HLJDT on arachidonic acid metabolites.. Our data demonstrate that oral administration of HLJDT significantly inhibited the inflammatory responses in carrageenan-injected rat air pouches, and also significantly reduced the production of nitric oxide (NO) and leukotriene B(4) (LTB(4)) in vivo, without any influence on biosynthesis of cyclooxygenase (COX)-derived eicosanoids. Similar behaviour of HLJDT was also observed by using calcium ionophore A23187-stimulated peritoneal macrophages, where HLJDT markedly inhibited eicosanoids derived from different lipoxygenases. The NO production and the mRNA expression of inducible nitric oxide synthase (iNOS) and chemotactic factors (CCL3, CCL4, CCL5 and CXCL2) were also inhibited by HLJDT in RAW 264.7 macrophages stimulated by lipopolysaccharide.. Our data revealed, for the first time, that HLJDT could inhibit biosynthesis of eicosanoids derived from different lipoxygenases. Also, HLJDT may exert its anti-inflammatory effects by its suppression on eicosanoid generation, NO production and gene transcription of chemotactic factors, which supports its effectiveness in the treatment of inflammatory diseases.

Topics: Animals; Anti-Inflammatory Agents; Calcimycin; Carrageenan; Cell Line; Chemotactic Factors; Chromatography, High Pressure Liquid; Drugs, Chinese Herbal; Eicosanoids; Inflammation; Leukotriene B4; Lipopolysaccharides; Lipoxygenase; Macrophages; Metabolic Networks and Pathways; Models, Animal; Nitric Oxide; Nitric Oxide Synthase Type II; Phytotherapy; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Sprague-Dawley; Receptors, Eicosanoid; RNA, Messenger; Tandem Mass Spectrometry

Exercise-induced bronchospasm (EIB) occurs in athletes with and without asthma. Studies have suggested an inflammatory basis for EIB in asthmatics; however whether inflammation plays a similar role in EIB in athletes without asthma remains unclear. Our objective was to determine whether there is evidence of an inflammatory basis for exercise-induced bronchospasm occurring in non-asthmatic athletes. Ninety-six athletes without asthma from varsity college teams underwent eucapnic voluntary hyperventilation testing. Sputum was induced from subjects with hypertonic saline inhalation post-eucapnic voluntary hyperventilation testing and was analyzed with enzyme-linked immunosorbent assays for IL-5, IL-8, IL-13, cysteinyl-leukotrienes, prostaglandin E2, histamine, leukotriene B4, and thromboxane B2. In addition, inflammatory (neutrophils, lymphocytes, eosinophils, and macrophages) and epithelial cell counts in sputum were recorded. Multivariate regression modeling showed a significant correlation between concentrations of select inflammatory mediators after eucapnic voluntary hyperventilation testing and severity of EIB. Means of the log-transformed concentrations of inflammatory mediators in EIB-positive athletes were significantly higher post-eucapnic voluntary hyperventilation than in EIB-negative athletes. Similar findings were not demonstrated with inflammatory cells. Concentrations of inflammatory mediators are higher in EIB-positive athletes than in EIB-negative athletes without asthma after eucapnic voluntary hyperventilation testing. The severity of EIB in our cohort also is significantly correlated with increased concentrations of select inflammatory mediators suggesting a potential inflammatory basis for EIB in athletes without asthma.

Topics: Adult; Age Factors; Asthma; Asthma, Exercise-Induced; Bronchial Hyperreactivity; Cohort Studies; Dinoprostone; Female; Histamine; Humans; Incidence; Inflammation; Inflammation Mediators; Leukotriene B4; Male; Multivariate Analysis; Probability; Respiratory Function Tests; Risk Assessment; Sensitivity and Specificity; Sex Factors; Sports; Sputum; Thromboxane B2

PGE2 and LTB4 are involved in inflammation and carcinogenesis in several tissues but have not been studied in prostate cancer and hyperplasia until now. We therefore measured PGE2 and LTB4 productions in a total of 206 prostate tissues from 116 patients including benign hyperplastic (90), pericancerous (106) and cancerous samples (10). We also analysed the influence of inflammation levels, prostate volume and glandular to epithelial ratio. PGE2 and LTB4 concentrations were measured using specific enzyme immunoassay kits. There was a correlation between PGE2 level, prostatic volume, inflammation score, and decreased glandular surface. By contrast, there was no correlation between LTB4 levels and inflammation or PGE2 production. Cancerous samples had higher LTB4 levels than pericancerous samples, but there was no difference in PGE2 levels. PGE2 and inflammation may be associated to stromal benign prostatic hyperplasia whereas LTB4 may play a role in prostate carcinogenesis.

Topics: Adult; Aged; Aged, 80 and over; Dinoprostone; Humans; Inflammation; Leukotriene B4; Male; Middle Aged; Organ Size; Prostatic Hyperplasia; Prostatic Neoplasms

Subcutaneous heat-coagulated egg white implants (EWI) induce chronic, intense local eosinophilia in mice, followed by asthma-like responses to airway ovalbumin challenge. Our goal was to define the mechanisms of selective eosinophil accumulation in the EWI model. EWI carriers were challenged i.p. with ovalbumin and the contributions of cellular immunity and inflammatory mediators to the resulting leukocyte accumulation were defined through cell transfer and pharmacological inhibition protocols. Eosinophil recruitment required Major Histocompatibility Complex Class II expression, and was abolished by the leukotriene B4 (LTB4) receptor antagonist CP 105.696, the 5-lipoxygenase inhibitor BWA4C and the 5-lipoxygenase activating protein inhibitor MK886. Eosinophil recruitment in EWI carriers followed transfer of: a) CD4+ (but not CD4-) cells, harvested from EWI donors and restimulated ex vivo; b) their cell-free supernatants, containing LTB4. Restimulation in the presence of MK886 was ineffective. CC chemokine receptor ligand (CCL)5 and CCL2 were induced by ovalbumin challenge in vivo. mRNA for CCL17 and CCL11 was induced in ovalbumin-restimulated CD4+ cells ex vivo. MK886 blocked induction of CCL17. Pretreatment of EWI carriers with MK886 eliminated the effectiveness of exogenously administered CCL11, CCL2 and CCL5. In conclusion, chemokine-producing, ovalbumin-restimulated CD4+ cells initiate eosinophil recruitment which is strictly dependent on LTB4 production.

Topics: Allergens; Animals; CD4-Positive T-Lymphocytes; Cell Movement; Chemokines; Chronic Disease; Dexamethasone; Eosinophilia; Eosinophils; Indoles; Inflammation; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Ovalbumin

The infiltrate in pneumonia is characterized by a large number of activated neutrophils, for which leukotriene B4 (LTB4) is a strong chemotactic agent. Exhaled breath condensate (EBC) is a non-invasive technique for studying the lower airways. The present study was conducted to measure EBC LTB4 as a potential non-invasive marker of inflammatory response in community acquired pneumonia (CAP).. Eighteen children with CAP and 17 healthy children were recruited (age 5-13). The CAP children underwent physical examination, chest X-ray, leukocyte count and C-reactive protein measurement. The CAP and the control children performed spirometry, exhaled nitric oxide measurement (FE(NO)) and EBC collection for LTB4 assessment. In the CAP children spirometry, FE(NO) and EBC collection were repeated twice over a 1-month follow-up.. LTB4 EBC concentrations were higher in children with CAP than in healthy controls (10 pg/ml [7.0-15.3] vs. 3 pg/ml [3.0-6.9], P = 0.001) and decreased after 1 week (3 pg/ml [3.0-7.2], P < 0.01) with no further change a month later. In the acute phase spirometry demonstrated a restrictive pattern that gradually improved later. No difference in FE(NO) levels was found between children with CAP and healthy controls.. Exhaled LTB4 levels increase in CAP and return to normal after 1 week. EBC collection is feasible in children with CAP and may represent a new way to non-invasively monitor the lung's biological response to infections.

Topics: Biomarkers; Breath Tests; Child; Community-Acquired Infections; Exhalation; Female; Humans; Inflammation; Leukotriene B4; Male; Neutrophils; Pneumonia

The inflammation-resolving lipid mediator resolvin E1 (RvE1) effectively stops inflammation-induced bone loss in vivo in experimental periodontitis. It was of interest to determine whether RvE1 has direct actions on osteoclast (OC) development and bone resorption.. Primary OC cultures derived from mouse bone marrow were treated with RvE1 and analysed for OC differentiation, cell survival and bone substrate resorption. Receptor binding was measured using radiolabelled RvE1. Nuclear factor (NF)-kappaB activation and Akt phosphorylation were determined with western blotting. Lipid mediator production was assessed with liquid chromatography tandem mass spectrometry.. OC growth and resorption pit formation were markedly decreased in the presence of RvE1. OC differentiation was inhibited by RvE1 as demonstrated by decreased number of multinuclear OC, a delay in the time course of OC development and attenuation of receptor activator of NF-kappaB ligand-induced nuclear translocation of the p50 subunit of NF-kappaB. OC survival and apoptosis were not altered by RvE1. Messenger RNA for both receptors of RvE1, ChemR23 and BLT(1) is expressed in OC cultures. Leukotriene B(4) (LTB(4)) competed with [(3)H]RvE1 binding on OC cell membrane preparations, and the LTB(4) antagonist U75302 prevented RvE1 inhibition of OC growth, indicating that BLT(1) mediates RvE1 actions on OC. Primary OC synthesized the RvE1 precursor 18R-hydroxy-eicosapentaenoic acid and LTB(4). Co-incubation of OC with peripheral blood neutrophils resulted in transcellular RvE1 biosynthesis.. These results indicate that RvE1 inhibits OC growth and bone resorption by interfering with OC differentiation. The bone-sparing actions of RvE1 are in addition to inflammation resolution, a direct action in bone remodelling.

Topics: Animals; Apoptosis; Bone Resorption; Cell Differentiation; Cells, Cultured; Dentin; Eicosapentaenoic Acid; Inflammation; Leukotriene B4; Mice; Osteoclasts; Radioligand Assay

Leukotriene B(4) (LTB(4)) plays a crucial role in the recruitment of neutrophils into the pleural space. We identified for the first time the mechanisms by which LTB(4) interacts with mesothelial cells and recruits neutrophils in the pleural compartment. Primary pleural mesothelial cells express both the proinflammatory receptor for LTB(4) BLT2, and the anti-inflammatory receptor for LTB(4), PPARalpha. Parapneumonic pleural effusions highly increase BLT2 expression and, via BLT2 activation, increase the adhesion between mesothelial cells and neutrophils and the expression of ICAM-1 on mesothelial cells. The block of PPARalpha further increases both cell adhesion and ICAM-1 expression. BLT2 activation promotes the activation, on mesothelial cells, of STAT-1 but not the activation of NF-kappaB transcription factor. The increase of ICAM-1 expression is achieved via increased tyrosine phosphorylation activity since herbimycin, a tyrosine kinase inhibitor, reduces and since Na orthovanadate, a tyrosine phosphatase inhibitor, further increases ICAM-1 expression. This study demonstrates that pleural mesothelial cells, expressing both proinflammatory and anti-inflammatory LTB(4) receptors, are able to mount an integrated response to LTB(4) with a prevalence of BLT2 activities in the presence of an inflammatory milieu within the pleura.

Topics: Adult; Aged; Blotting, Western; Cell Adhesion; Cells, Cultured; Chemotaxis, Leukocyte; Epithelium; Flow Cytometry; Humans; Inflammation; Intercellular Adhesion Molecule-1; Leukotriene B4; Middle Aged; Neutrophil Infiltration; Pleura; Pleural Effusion; Pneumonia; PPAR alpha; Receptors, Leukotriene B4

Quinoid polycyclic aromatic hydrocarbons are potent redox-active compounds that undergo enzymatic and nonenzymatic redox cycling with their semiquinone radical. We previously reported that acenaphthenequinone (AcQ) can damage human lung epithelial A549 cells through the formation of reactive species (RS). However, the biochemical mechanisms by which RS-generating enzymes cause oxidative burst during AcQ exposure remain elusive. Here we examined the biochemical mechanism of AcQ-induced RS generation by using selective metabolic inhibitors in A549 cells. We found that AA861, a 5-lipoxygenase (5-LO)-specific inhibitor significantly decreases RS generation. This inhibition of RS seems to be 5-LO specific because other inhibitors did not suppress AcQ-induced RS generation by nicotinamide adenine nucleotide phosphate (reduced) oxidase and/or xanthine oxidase. In addition, the inhibition of 5-LO by AA861 markedly reduced AcQ-induced nuclear factor kappa B (NF-kappa B) activation. We further found the activation of 5-LO pathway by exposing cells to AcQ mediates the secretion of inflammatory leukotriene B4, which can be significantly suppressed by a potent RS scavenger, N-acetylcysteine. Thus, based on our findings, we propose that AcQ-induced damage is likely due to increased RS generation and NF-kappa B activity through 5-LO activation.

Topics: Acenaphthenes; Acetylcysteine; Antioxidants; Arachidonate 15-Lipoxygenase; Benzoquinones; Biotransformation; Blotting, Western; Cell Line, Tumor; Enzyme Activation; Genes, Reporter; Humans; Immunoenzyme Techniques; Indicators and Reagents; Inflammation; Leukotriene B4; Luciferases; NF-kappa B; Oxidative Stress; Up-Regulation

Leptin is an adipocyte-derived hormone/cytokine that links nutritional status with neuroendocrine and immune functions. Lipid bodies (lipid droplets) are emerging as dynamic organelles with roles in lipid metabolism and inflammation. Here we investigated the roles of leptin in signaling pathways involved in cytoplasmic lipid body biogenesis and leukotriene B(4) synthesis in macrophages. Our results demonstrated that leptin directly activated macrophages and induced the formation of adipose differentiation-related protein-enriched lipid bodies. Newly formed lipid bodies were sites of 5-lipoxygenase localization and correlated with an enhanced capacity of leukotriene B(4) production. We demonstrated that leptin-induced macrophage activation was dependent on phosphatidylinositol 3-kinase (PI3K) activity, since the lipid body formation was inhibited by LY294002 and was absent in the PI3K knock-out mice. Leptin induces phosphorylation of p70(S6K) and 4EBP1 key downstream signaling intermediates of the mammalian target of rapamycin (mTOR) pathway in a rapamycin-sensitive mechanism. The mTOR inhibitor, rapamycin, inhibited leptin-induced lipid body formation, both in vivo and in vitro. In addition, rapamycin inhibited leptin-induced adipose differentiation-related protein accumulation in macrophages and lipid body-dependent leukotriene synthesis, demonstrating a key role for mTOR in lipid body biogenesis and function. Our results establish PI3K/mTOR as an important signaling pathway for leptin-induced cytoplasmic lipid body biogenesis and adipose differentiation-related protein accumulation. Furthermore, we demonstrate a previously unrecognized link between intracellular (mTOR) and systemic (leptin) nutrient sensors in macrophage lipid metabolism. Leptin-induced increased formation of cytoplasmic lipid bodies and enhanced inflammatory mediator production in macrophages may have implications for obesity-related cardiovascular diseases.

Topics: Adipocytes; Animals; Cell Differentiation; Cells, Cultured; Chromones; Enzyme Inhibitors; Inflammation; Leptin; Leukotriene B4; Lipid Metabolism; Macrophage Activation; Macrophages, Peritoneal; Male; Membrane Proteins; Mice; Mice, Knockout; Morpholines; Organelles; Perilipin-2; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinases; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; TOR Serine-Threonine Kinases

Leukotrienes (LTs) are powerful proinflammatory lipid mediators that may play a central role in cardiovascular diseases, including arteriosclerosis, myocardial infarction, and stroke. Owing to restricted expression of 5-lipoxygenase (5-LO), the enzyme required for their synthesis, LTs are almost exclusively produced by myeloid cells. Here, we report that human cytomegalovirus (HCMV) infection of human vascular smooth muscle cells (SMCs) increases 5-LO mRNA levels by up to 170-fold in a dose- and time-dependent manner. Infected cells expressed 5-LO protein, as shown by immunohistochemistry, enabling them to synthesize bioactive LTB(4). HCMV-infected vascular SMCs expressing 5-LO protein were readily detected in tissue samples from CMV-infected patients with inflammatory bowel disease or AIDS. Thus, pathogen-induced LT production in HCMV-infected tissues may contribute to local inflammation, consistent with the ability of HCMV to control cellular and immunological functions. HCMV-induced LT biosynthesis in SMCs offers a molecular mechanism to explain HCMV-induced pathogenesis in inflammatory diseases.

Topics: Arachidonate 5-Lipoxygenase; Cells, Cultured; Cytomegalovirus Infections; Fibroblasts; Gene Expression Regulation; Humans; Immunoenzyme Techniques; Immunohistochemistry; Inflammation; Leukotriene B4; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle

The accumulation of eosinophils in inflammatory foci is a hallmark characteristic of Th2 inflammation. Nevertheless, the expression of inhibitory receptors such as paired immunoglobulin-like receptor B (PIR-B) and their function regulating eosinophil accumulation have received limited attention. We now report that Pirb was up-regulated in an eosinophil-dependent manner in the lungs of allergen-challenged and interleukin (IL)-13-overexpressing mice. Eosinophils expressed high levels of PIR-B, and Pirb(-/-) mice displayed increased gastrointestinal eosinophils. Consistent with these findings, PIR-B negatively regulated eotaxin-dependent eosinophil chemotaxis in vivo and in vitro. Surprisingly, Pirb(-/-) eosinophils and neutrophils had decreased leukotriene B4 (LTB(4))-dependent chemotactic responses in vitro. Furthermore, eosinophil accumulation was decreased in a chitin-induced model, partially dependent on LTB(4). Mechanistic analysis using a miniphosphoproteomic approach revealed that PIR-B recruits activating kinases after LTB(4) but not eotaxin stimulation. Consequently, eotaxin-activated Pirb(-/-) eosinophils displayed markedly increased extracellular signal-related kinase 1 and 2 (ERK1/2) phosphorylation, whereas LTB(4)-activated eosinophils had reduced ERK1/2 phosphorylation. We provide multiple lines of evidence supporting a model in which PIR-B displays opposing but potent regulatory functions in granulocyte activation. These data change the conventional wisdom that inhibitory receptors are restricted to inhibitory signals; we therefore propose that a single receptor can have dual functionality in distinct cell types after unique cellular signals.

Topics: Allergens; Animals; Chemokine CCL11; Chemokine CCL24; Chemotaxis; Chitin; Eosinophils; Esophagus; Female; Gastrointestinal Tract; Gene Expression; Inflammation; Interleukin-13; Leukotriene B4; Lung; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Mutant Strains; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Phosphorylation; Receptors, CCR3; Receptors, Immunologic

Inflammation governs atherosclerosis and is firmly regulated. Endogenous mechanisms to keep inflammation self-limiting are unclear. In the present article, we propose that RvE1 (resolution E1), an endogenous lipid mediator, inhibits inflammation through "pro-resolution" and counter-modulating immunity in atherosclerosis. The background comes from studies on the potent programming of resolution and immuno-inflammation of RvE1 and its precursor, eicosapentaenoic acid, in treating chronic inflammatory disease with unknown mechanisms. In light of the interaction between RvE1 and leukotrieneB4 (LTB4) and their potential impaired immunity regulation hematostasis, we hypothesize that RvE1 play an anti-atherosclerosis and plaque stabilization role through "pro-resolution" and anti-inflammation which may be realized by blocking LTB4/BLT1 (receptor of LTB4) pathway. Our hypothesis generates potentially clinical viewpoint to systematically look for pro- and anti-inflammation and "pro-resolution" process in atherosclerosis. Furthermore, we suggest that RvE1 might be particularly indicated for the treatment of atherosclerotic diseases and plaque stabilization which might ensure an effective management for patients with coronary artery disease.

Topics: Anti-Inflammatory Agents; Atherosclerosis; Coronary Artery Disease; Eicosapentaenoic Acid; Hemostasis; Humans; Immune System; Inflammation; Leukotriene B4; Lipids; Models, Biological; Models, Theoretical

Lysophosphatidylcholine (LPC) is the major bioactive lipid component of oxidized LDL, thought to be responsible for many of the inflammatory effects of oxidized LDL described in both inflammatory and endothelial cells. Inflammation-induced transformation of vascular smooth muscle cells from a contractile phenotype to a proliferative/secretory phenotype is a hallmark of the vascular remodeling that is characteristic of atherogenesis; however, the role of LPC in this process has not been fully described. The present study tested the hypothesis that LPC is an inflammatory stimulus in coronary artery smooth muscle cells (CASMCs). In cultured human CASMCs, LPC stimulated time- and concentration-dependent release of arachidonic acid that was sensitive to phospholipase A2 and C inhibition. LPC stimulated the release of arachidonic acid metabolites leukotriene-B4 and 6-keto-prostaglandin F1alpha, within the same time course. LPC was also found to stimulate basic fibroblast growth factor release as well as stimulating the release of the cytokines GM-CSF, IL-6, and IL-8. Optimal stimulation of these signals was obtained via palmitic acid-substituted LPC species. Stimulation of arachidonic acid, inflammatory cytokines and growth factor release, implies that LPC might play a multifactorial role in the progression of atherosclerosis, by affecting inflammatory processes.

Topics: 6-Ketoprostaglandin F1 alpha; Arachidonic Acid; Arachidonic Acids; Cells, Cultured; Coronary Vessels; Cytokines; Fibroblast Growth Factor 2; Humans; Inflammation; Leukotriene B4; Lipids; Lysophosphatidylcholines; Myocytes, Smooth Muscle; Phospholipases; Tritium

We investigated factors that may be involved in the reduced leukocyte migration observed in intrauterine undernourished rats.. Male Wistar rat offspring (8-9 wk of age) of dams fed during pregnancy with 50% less food than control dams were used to measure L-selectin expression (by flow cytometry), bone marrow cell count, blood cell count, laminin and type IV collagen in the basal membrane of venules of the spermatic fascia (by immunohistochemistry), total protein level and serum albumin, and the production of leukotriene B4 after stimulation with tumor necrosis factor-alpha and corticosterone plasma levels (by enzyme-linked immunosorbent assay).. Hypocellularity in bone marrow and peripheral blood and reduced L-selectin expression were found in the undernourished rat offspring (UR) compared with nourished offspring (NR; P < 0.05). Type IV collagen in the basal membrane of the venules of the spermatic fascia was less in UR than in NR (P < 0.05). The total protein levels and serum albumin did not differ between the two groups. Leukotriene B4 production after stimulation with tumor necrosis factor-alpha was lower in UR (P < 0.05). These differences could not be attributed to circulating glucocorticoids levels, which were not different in the NR and UR groups.. Our data suggest that all observed differences contribute to reduced leukocyte migration in undernourishment.

Topics: Animals; Basement Membrane; Bone Marrow Cells; Cell Movement; Collagen Type IV; Corticosterone; Female; Fetal Diseases; Flow Cytometry; Immunohistochemistry; Inflammation; L-Selectin; Laminin; Leukocytes; Leukotriene B4; Male; Malnutrition; Pregnancy; Prenatal Exposure Delayed Effects; Prenatal Nutritional Physiological Phenomena; Random Allocation; Rats; Rats, Wistar; Serum Albumin

Leukotriene B(4) (LTB(4)) is a potent inflammatory mediator and stimulates the immune response. In addition, LTB(4) promotes leukocyte functions such as phagocytosis, chemotaxis and chemokinesis of polymorphonuclear leukocytes, as well as modulates cytokine release. However, some physicochemical characteristics of leukotrienes, such as poor solubility in water and chemical instability, make them difficult to administer in vivo. The aim of this study was to develop LTB(4)-loaded microspheres (MS) that prolong and sustain the in vivo release of this mediator. An oil-in-water emulsion solvent extraction-evaporation method was chosen to prepare the lipid-loaded MS. We determined their diameters, evaluated the in vitro release of LTB(4), using enzyme immunoassay and evaluated in vitro MS uptake by peritoneal macrophages. To assess the preservation of neutrophil chemoattractant activity, LTB(4)-loaded MS were tested in vitro (in a modified Boyden microchamber) and in vivo, after intratracheal administration.

Topics: Animals; Chemotaxis, Leukocyte; Glycolates; Humans; Inflammation; Lactic Acid; Leukotriene B4; Macrophages, Peritoneal; Male; Mice; Microspheres; Models, Theoretical; Neutrophils; Particle Size; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Pulmonary Alveoli

Leukotriene A(4) hydrolase (LTA(4)H) catalyzes production of the proinflammatory lipid mediator, leukotriene (LT) B(4), which is implicated in a number of inflammatory diseases. We have identified a potent and selective inhibitor of both the epoxide hydrolase and aminopeptidase activities of recombinant human LTA(4)H (IC(50), approximately 10 nM). In a murine model of arachidonic acid-induced ear inflammation, the LTA(4)H inhibitor, JNJ-26993135 (1-[4-(benzothiazol-2-yloxy)-benzyl]-piperidine-4-carboxylic acid), dose-dependently inhibited ex vivo LTB(4) production in blood, in parallel with dose-dependent inhibition of neutrophil influx (ED(50), 1-3 mg/kg) and ear edema. In murine whole blood and in zymosan-induced peritonitis, JNJ-26993135 selectively inhibited LTB(4) production, without affecting cysteinyl leukotriene production, while maintaining or increasing production of the anti-inflammatory mediator, lipoxin (LX) A(4). The 5-lipoxygenase (5-LO) inhibitor zileuton showed inhibition of LTB(4), LTC(4), and LXA(4) production. Although zileuton inhibited LTB(4) production in the peritonitis model more effectively than the LTA(4)H inhibitor, the influx of neutrophils into the peritoneum after 1 and 2 h was significantly higher in zileuton- versus JNJ-26993135-treated animals. This difference may have been mediated by the increased LXA(4) levels in the presence of the LTA(4)H inhibitor. The selective inhibition of LTB(4) production by JNJ-26993135, while increasing levels of the anti-inflammatory mediator, LXA(4), may translate to superior therapeutic efficacy versus 5-LO or 5-LO-activating protein inhibitors in LTB(4)-mediated inflammatory diseases.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Ascitic Fluid; Benzothiazoles; Dogs; Ear; Edema; Eicosanoids; Enzyme Inhibitors; Epoxide Hydrolases; Female; Humans; Hydroxyurea; Inflammation; Leukotriene B4; Leukotriene C4; Lipoxins; Lipoxygenase Inhibitors; Mice; Mice, Inbred BALB C; Mice, Inbred Strains; Neutrophil Infiltration; Peritonitis; Piperidines; Recombinant Proteins

Our previous study demonstrated that feeding ganglioside increased total ganglioside content while decreasing cholesterol and caveolin-1 content in developing rat intestinal lipid microdomains. Cholesterol or caveolin depletion in membranes inhibits inflammatory signaling by disrupting microdomain structure. We hypothesized that dietary ganglioside-induced reduction in cholesterol content will reduce proinflammatory mediators in the intestinal mucosa after acute exposure to bacterial endotoxin. Weanling rats were fed semipurified diets with 0.1% (wt/wt of total fat) gangliosides (treatment) or without ganglioside (control). After 2 weeks of feeding, half of animals from each diet group were injected with saline or lipopolysaccharide (LPS) endotoxin (Escherichia coli serotype O111:B4, intraperitoneal, 3 mg/kg body weight) to induce acute gut inflammation. Intestinal mucosa and blood were collected after 6 h. The effect of dietary ganglioside on proinflammatory mediators including cholesterol, platelet-activating factor, prostaglandin E2, leukotriene B4 (LTB4), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha) was determined in inflamed mucosa and blood. Feeding animals the control diet increased cholesterol content in intestinal lipid microdomains by 92% after LPS injection compared with saline injection. Animals fed the ganglioside diet significantly decreased cholesterol content in lipid microdomains by 60% compared with animals fed the control diet. Feeding animals the ganglioside diet increased total ganglioside content by 90% while decreasing platelet-activating factor content by 45% in the inflamed mucosa by acute systemic exposure to LPS compared with animals fed the control diet. When animals were fed the ganglioside diet, the levels of prostaglandin E2, LTB4, IL-1beta, and TNF-alpha were lower in inflamed mucosa, and LTB4, IL-1beta, and TNF-alpha were decreased in plasma by 41%, 58%, and 55% compared with control animals, respectively. The present study demonstrates that dietary gangliosides inhibit proinflammatory signals in the intestine and blood induced by acute inflammation of LPS and suggests therapeutic potential in the treatment and management of acute local and systemic inflammatory diseases.

Topics: Animals; Cholesterol; Dietary Fats; Dinoprostone; Gangliosides; Inflammation; Interleukin-1beta; Intestinal Mucosa; Leukotriene B4; Lipopolysaccharides; Male; Membrane Microdomains; Platelet Activating Factor; Rats; Rats, Sprague-Dawley; Signal Transduction; Tumor Necrosis Factor-alpha

Human bronchial epithelial cells synthesize cyclooxygenase and 15-lipoxygenase products, but the 5-lipoxygenase (5-LO) pathway that generates the leukotriene (LT) family of bronchoconstrictor and pro-inflammatory mediators is thought to be restricted to leucocytes.. We hypothesized that human bronchial epithelial cells (HBECs) express a complete and active 5-LO pathway for the synthesis of LTB4 and LTC4, either constitutively or after stimulation.. Flow cytometry, RT-PCR, Western blotting, enzyme immunoassays and reverse-phase high-performance liquid chromatography were used to investigate constitutive and stimulated expression of 5-LO pathway enzymes and the synthesis of LTs B4 and C4 in primary HBECs and in the 16-HBE 14o- cell line.. Constitutive mRNA and protein expression for 5-LO, 5-LO-activating protein (FLAP), LTA4 hydrolase and LTC4 synthase were demonstrated in primary HBECs and in the 16-HBE 14o- cell line. In 16-HBE 14o- cells, treatment with calcium ionophore A23187, bradykinin or LPS up-regulated the expression of these enzymes. The up-regulation of 5-LO was blocked by the anti-inflammatory glucocorticoid dexamethasone. Human bronchial epithelial cells were shown to generate bioactive LTs, with primary HBECs generating 11-fold more LTC4 and five-fold more LTB4 than 16-HBE 14o- cells. LT production was enhanced by ionophore treatment and blocked by the FLAP inhibitor MK-886.. Expression of an active and inducible 5-LO pathway in HBEC suggests that damaged or inflamed bronchial epithelium may synthesize LTs that contribute directly to bronchoconstriction and leucocytosis in airway inflammation.

Topics: 5-Lipoxygenase-Activating Proteins; Arachidonate 15-Lipoxygenase; Arachidonate 5-Lipoxygenase; Bradykinin; Bronchi; Bronchoconstriction; Bronchoconstrictor Agents; Calcimycin; Carrier Proteins; Cell Line; Epithelial Cells; Gene Expression Regulation, Enzymologic; Glutathione Transferase; Humans; Inflammation; Inflammation Mediators; Ionophores; Leukotriene B4; Leukotriene C4; Lipopolysaccharides; Membrane Proteins; Prostaglandin-Endoperoxide Synthases; RNA, Messenger; Up-Regulation; Vasodilator Agents

Excessive leukocyte proliferation and proinflammatory mediators release represent common phenomena in several chronic inflammatory diseases. Multiple evidences identify lysophosphatidic acid (LPA), a small lipid endowed with pleiotropic activities, as an important modulator of both proliferation and activation of different cell types involved in several inflammation-associated pathologies. However, its possible role on monocyte proinflammatory activation is not fully understood yet. Aim of the present study was to investigate LPA effects on THP-1 cells in terms of proliferation, reactive oxygen intermediates (ROI) production and release of arachidonic acid-derived inflammatory mediators. Actually, LPA significantly increased both DNA synthesis and ROI production as well as prostaglandin E(2) release and the upregulation of LPA(3) receptor expression. These findings identified LPA as both a growth factor and a triggering mediator of proinflammatory response in THP-1 cells.

Topics: Arachidonic Acid; Cell Line; Cell Proliferation; Dinoprostone; DNA Replication; Enzyme Activation; Humans; Inflammation; Inflammation Mediators; Isoxazoles; Leukotriene B4; Lysophospholipids; Monocytes; NADPH Oxidases; Propionates; Reactive Oxygen Species; Receptors, Lysophosphatidic Acid; RNA, Messenger; Time Factors; Up-Regulation

The anti-inflammatory properties of three flavanones isolated from Inula viscosa, sakuranetin, 7-O-methylaromadendrin, and 3-acetyl-7-O-methylaromadendrin, have been tested both in vitro and in vivo. Acute inflammation in vivo was induced by means of topical application of 12-O-tetradecanoylphorbol 13-acetate (TPA) to mouse ears or by subcutaneous injection of phospholipase A(2) (PLA(2)) into mouse paws. The test compounds were evaluated in vitro for their effect on both the metabolism of arachidonic acid and on the release and/or activity of enzymes involved in the inflammatory response such as elastase, myeloperoxidase (MPO), and protein kinase C (PKC). The most active compounds in vivo against PLA(2)-induced paw oedema were 7-O-methylaromadendrin (ED(50)=8 mg/kg) and sakuranetin (ED(50)=18 mg/kg). In contrast, the most potent compound against TPA-induced ear oedema was 3-acetyl-7-O-methylaromadendrin (ED(50)=185 microg/ear), followed by sakuranetin (ED(50)=205 microg/ear). In vitro, the latter compound was the most potent inhibitor of leukotriene (LT) B(4) production by peritoneal rat neutrophils (IC(50)=9 microM) and it was also the only compound that directly inhibited the activity of 5-lipoxygenase (5-LOX). 3-Acetyl-7-O-methylaromadendrin also inhibited LTB(4) production (IC(50)=15 microM), but had no effect on 5-LOX activity. The only flavanone that inhibited the secretory PLA(2) activity in vitro was 7-O-methylaromadendrin. This finding may partly explain the anti-inflammatory effect observed in vivo, although other mechanisms such as the inhibition of histamine release by mast cells may also be implicated. Sakuranetin at 100 microM was found to inhibit elastase release, although this result is partly due to direct inhibition of the enzyme itself. At the same concentration, 7-O-methylaromadendrin only affected the enzyme release. Finally, none of the flavanones exhibited any effect on MPO or PKC activities. Taken together, these findings indicate that sakuranetin may be a selective inhibitor of 5-LOX.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonate 5-Lipoxygenase; Arachidonic Acid; Cell Survival; Dinoprostone; Edema; Female; Flavonols; Histamine Release; Humans; In Vitro Techniques; Inflammation; Inula; Leukocyte Elastase; Leukotriene B4; Mice; Neutrophils; Peroxidase; Phospholipases A; Protein Kinase C; Rats; Tetradecanoylphorbol Acetate

Acemetacin is regarded as a pro-drug of indomethacin and induces significantly less gastric damage but the reasons for this greater gastric safety of acemetacin are unclear. The anti-inflammatory effects of acemetacin have been attributed, at least in part, to its hepatic biotransformation to indomethacin. The aim of this study was to determine the effects of acemetacin and indomethacin in an in vivo model of acute inflammation and to examine the importance of biotransformation of acemetacin (to indomethacin) to its anti-inflammatory actions.. The zymosan airpouch model was used in rats. Indomethacin or acemetacin (2.7-83.8 micromol kg(-1)) were administered orally or directly into the pouch. Leukocyte infiltration, prostaglandin (PG) E(2) and leukotriene (LT) B(4) levels in exudates, and whole blood thromboxane (TX) B(2) synthesis were measured.. Acemetacin was rapidly converted to indomethacin after its administration. Both acemetacin and indomethacin elicited comparable, dose-dependent reductions of leukocyte infiltration and of PGE(2) and TXB(2) synthesis. However, indomethacin induced more gastric damage than acemetacin and elevated LTB(4) production in the airpouch.. The similar effects of acemetacin and indomethacin on leukocyte infiltration and PG synthesis are consistent with rapid biotransformation of acemetacin to indomethacin. Some of this biotransformation may occur extra-hepatically, for instance in inflammatory exudates. Acemetacin probably exerts actions independent of conversion to indomethacin, given the different effects of these two drugs on LTB(4) production. Such differences may contribute to the relative gastric safety of acemetacin compared to indomethacin.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Area Under Curve; Biotransformation; Chromatography, High Pressure Liquid; Cyclooxygenase 1; Cyclooxygenase 2; Dinoprostone; Exudates and Transudates; Indomethacin; Inflammation; Injections, Subcutaneous; Leukotriene B4; Male; Prostaglandins; Rats; Rats, Wistar; Stomach Ulcer; Thromboxanes; Zymosan

To ascertain whether constitutive androstane receptor (CAR) activation by 1,4-bis-[2-(3,5,-dichloropyridyloxy)] benzene (TCPOBOP) modulates steatohepatitis in the methionine choline-deficient (MCD) diet-fed animal.. C57/BL6 wild-type mice were fed the MCD or standard diet for 2 wk and were treated with either the CAR agonist, TCPOBOP, or the CAR inverse agonist, androstanol.. Expression of CYP2B10 and CYP3A11, known CAR target genes, increased 30-fold and 45-fold, respectively, in TCPOBOP-treated mice fed the MCD diet. TCPOBOP treatment reduced hepatic steatosis (44.6 +/- 5.4% vs 30.4 +/- 4.5%, P < 0.05) and serum triglyceride levels (48 +/- 8 vs 20 +/- 1 mg/dL, P < 0.05) in MCD diet-fed mice as compared with the standard diet-fed mice. This reduction in hepatic steatosis was accompanied by an increase in enzymes involved in fatty acid microsomal omega-oxidation and peroxisomal beta-oxidation, namely CYP4A10, LPBE, and 3-ketoacyl-CoA thiolase. The reduction in steatosis was also accompanied by a reduction in liver cell apoptosis and inflammation. In contrast, androstanol was without effect on any of the above parameters.. CAR activation stimulates induction of genes involved in fatty acid oxidation, and ameliorates hepatic steatosis, apoptosis and inflammation.

Topics: Animals; Apoptosis; Choline Deficiency; Constitutive Androstane Receptor; Fatty Acids; Fatty Liver; Inflammation; Leukotriene B4; Methionine; Mice; Mice, Inbred C57BL; PPAR alpha; Pyridines; Receptors, Cytoplasmic and Nuclear; Transcription Factors

Resolvin E1 (RvE1) is a potent proresolving mediator of inflammation derived from omega-3 eicosapentaenoic acid that acts locally to stop leukocyte recruitment and promote resolution. RvE1 displays potent counter-regulatory and tissue-protective actions in vitro and in vivo. Periodontal disease is a local inflammatory disease initiated by bacteria characterized by neutrophil-mediated tissue injury followed by development of a chronic immune lesion. In this study, we report the treatment of established periodontitis using RvE1 as a monotherapy in rabbits compared with structurally related lipids PGE(2) and leukotriene B(4). PGE(2) and leukotriene B(4) each enhanced development of periodontitis and worsened the severity of disease. Promotion of resolution of inflammation as a therapeutic target with RvE1 resulted in complete restoration of the local lesion, and reduction in the systemic inflammatory markers C-reactive protein and IL-1beta. This report is the first to show that resolution of inflammation by a naturally occurring endogenous lipid mediator results in complete regeneration of pathologically lost tissues, including bone.

Topics: Alveolar Bone Loss; Animals; C-Reactive Protein; Chronic Disease; Dinoprostone; Disease Models, Animal; Eicosapentaenoic Acid; Homeostasis; Inflammation; Inflammation Mediators; Interleukin-1beta; Leukotriene B4; Neutrophil Infiltration; Neutrophils; Periodontitis; Rabbits

The total burden of infection at various sites may affect the progression of atherosclerosis and Alzheimer's disease (AD), the risk being modulated by host genotype. The role of lipopolysaccharide (LPS) receptor TLR4 is paradigmatic. It initiates the innate immune response against gram-negative bacteria, and TLR4 single nucleotide polymorphisms (SNPs), such as +896A/G, known to attenuate receptor signaling, have been described. This SNP shows a significantly lower frequency in patients affected by myocardial infarction or AD. Thus, people genetically predisposed to developing lower inflammatory activity seem to have less chance of developing cardiovascular disease (CVD) or AD. In the present report, to validate this hypothesis, the levels of the eicosanoids, leukotriene B4 (LTB4) and prostaglandin E2 (PGE2), known to be involved as mediators in age-related diseases, were determined by an enzyme-linked immunosorbent assay in supernatants from a whole blood assay, after stimulation with subliminal doses of LPS from Escherichia coli. The samples, genotyped for the +896A/G SNP, were challenged with LPS for 4, 24, and 48 h. Both LTB4 and PGE2 values were significantly lower in carriers bearing the TLR4 mutation. Therefore, the pathogen burden, by interacting with the host genotype, determines the type and intensity of the inflammatory responses accountable for proinflammatory status, CVD, AD, and unsuccessful aging (i.e., age-related inflammatory diseases).

Topics: Adult; Aging; Alzheimer Disease; Blood Cells; Cells, Cultured; Dinoprostone; Escherichia coli; Escherichia coli Infections; Female; Genotype; Humans; Immunity, Innate; Inflammation; Leukotriene B4; Lipopolysaccharides; Male; Middle Aged; Myocardial Infarction; Polymorphism, Single Nucleotide; Time Factors; Toll-Like Receptor 4

Aging may be accompanied by a low grade chronic up-regulation of inflammatory mediators. A variety of endogenous locally released mediators as well as inflammatory cells have been reported in the human oral cavity. The aim of this investigation was to determine the presence of different classes of inflammatory mediators in human saliva and correlate the levels with age.. Unstimulated whole buccal salivary samples were obtained in the morning from 94 healthy volunteers within 30 minutes after waking. None of the participants had taken aspirin in the week prior to the saliva collection. Lysozyme activity, eicosanoid levels (prostaglandin E(2) and leukotriene B(4)) and MMP-9 activity were measured. The antimicrobial activity (lysozyme activity) was not correlated with age whereas PGE(2) levels were markedly correlated with age (r = 0.29; P<0.05; n = 56). Saliva from healthy subjects (< or =40 years) compared with data derived from older volunteers (>40 years) demonstrated a significant increase in the mean values for PGE(2) and MMP-9 activity with age. In addition, significant correlations were observed between LTB(4) and PGE(2) (r = 0.28; P<0.05; n = 56) and between LTB(4) levels and MMP-9 activity in smokers (r = 0.78; P<0.001; n = 15).. The presence of significant levels and activity of inflammatory mediators in saliva suggests that the oral cavity of healthy subjects may be in a constant low state of inflammation associated with age.

Topics: Adolescent; Adult; Aged; Aging; Dinoprostone; Female; Humans; Inflammation; Inflammation Mediators; Leukotriene B4; Matrix Metalloproteinase 9; Middle Aged; Mouth; Muramidase; Saliva

We have recently shown that the leukotriene B(4) (LTB(4))-BLT1 pathway is important in early effector T-cell recruitment in mouse models of inflammation. Here we characterize the phenotype and function of human peripheral blood BLT1(+) T cells in health and illustrate their involvement in asthma and acute infection. In healthy individuals, BLT1(+) T cells are a rare peripheral blood T-cell population enriched for the activation markers CD38 and HLA-DR. Compared with BLT1(-) T cells, a larger proportion of peripheral blood BLT1(+) T cells express the effector cytokines IFNgamma and IL-4 and inflammatory chemokine receptors, CCR1, CCR2, CCR6, and CXCR1. Consequently, in healthy individuals peripheral blood BLT1(+) T cells are a rare antigen-primed T-cell subset with unique phenotypic, migratory, and functional properties. BLT1 expression on T cells is tightly regulated by inflammation and only transiently expressed after naive T-cell activation by dendritic cells. Although rare in the peripheral blood of healthy individuals, BLT1(+) T cells are markedly increased in frequency in the peripheral blood in response to acute Epstein-Barr virus (EBV) infection and moderately increased in the airways of asymptomatic allergic asthmatics. Our studies provide novel insights into the LTB(4)-BLT1 lipid chemoattractant pathway in human T-cell responses, and how it may link innate and adaptive immunity.

Topics: Acute Disease; ADP-ribosyl Cyclase 1; Asthma; Bronchoalveolar Lavage Fluid; Case-Control Studies; Cells, Cultured; Epstein-Barr Virus Infections; Herpesvirus 4, Human; HLA-DR Antigens; Humans; Inflammation; Interferon-gamma; Interleukin-4; Leukotriene B4; Lymphocyte Activation; Protein Serine-Threonine Kinases; Receptors, CCR2; Receptors, CCR6; Receptors, Chemokine; Receptors, Interleukin-8A; Receptors, Leukotriene B4; Receptors, Purinergic P2; T-Lymphocytes

It is unclear how chronic expectoration influences airway inflammation in patients with chronic lung disease. The aim of this study was to investigate factors influencing inflammation in induced sputum samples, including, in particular, chronic sputum production. Myeloperoxidase, interleukin-8, leukotriene B4 (LTB4), neutrophil elastase, secretory leukoprotease inhibitor (SLPI) and protein leakage were compared in induced sputum samples from 48 patients (36 with chronic expectoration) with COPD (with and without alpha-1-antitrypsin deficiency; AATD), 9 individuals with AATD but without lung disease and 14 healthy controls. There were no differences in inflammation in induced sputum samples from healthy control subjects and from AATD deficient patients with normal lung function but without chronic expectoration (P>0.05). Inflammation in induced sputum from AATD patients with airflow obstruction and chronic sputum expectoration was significantly greater than for similar patients who did not expectorate: Interleukin-8 (P<0.01), elastase activity (P=0.01), and protein leakage (P<0.01). The presence of spontaneous sputum expectoration in AATD patients with airflow obstruction was associated with increased neutrophilic airway inflammation in induced sputum samples. The presence of chronic expectoration in some patients will clearly complicate interpretation of studies employing sputum induction where this feature has not been identified.

Topics: Adult; Aged; alpha 1-Antitrypsin Deficiency; Biomarkers; Bronchi; Case-Control Studies; Cough; Female; Humans; Inflammation; Interleukin-8; Leukotriene B4; Male; Middle Aged; Pancreatic Elastase; Peroxidase; Pulmonary Disease, Chronic Obstructive; Saline Solution, Hypertonic; Serum Albumin; Sputum

The expression of enzymes involved in leukotriene and prostaglandin signalling pathways, of interleukins 6 and 8 and of peroxisome proliferator-activated receptors in sebaceous glands of acne-involved facial skin was compared with those of non-involved skin of acne patients and of healthy individuals. Moreover, 5-lipoxygenase and leukotriene A(4) hydrolase were expressed at mRNA and protein levels in vivo and in SZ95 sebocytes in vitro (leukotriene A(4) hydrolase > 5-lipoxygenase), while 15-lipoxygenase-1 was only detected in cultured sebocytes. Cyclooxygenase-1 and cyclooxygenase-2 were also present. Peroxisome proliferator-activated receptors were constitutively expressed. Enhanced 5-lipoxygenase, cyclooxygenase 2 and interleukin 6 expression was detected in acne-involved facial skin. Arachidonic acid stimulated leukotriene B(4) and interleukin 6 release as well as prostaglandin E(2) biosynthesis in SZ95 sebocytes, induced abundant increase in neutral lipids and down-regulated peroxisome proliferator-activated receptor-alpha, but not receptor-gamma1 mRNA levels, which were the predominant peroxisome proliferator-activated receptor isotypes in SZ95 sebocytes. In conclusion, human sebocytes possess the enzyme machinery for functional leukotriene and prostaglandin pathways. A comprehensive link between inflammation and sebaceous lipid synthesis is provided.

Topics: Acne Vulgaris; Adolescent; Adult; Arachidonate 5-Lipoxygenase; Arachidonic Acid; Cells, Cultured; Cyclooxygenase 2; Dinoprostone; Epoxide Hydrolases; Female; Humans; Inflammation; Interleukin-6; Interleukin-8; Leukotriene B4; Male; Membrane Proteins; Peroxisome Proliferator-Activated Receptors; Protein Isoforms; Sebaceous Glands

Tea has been shown to possess several health beneficial properties primarily due to its polyphenolic content. The major polyphenolic compounds in black tea leaves are theaflavins (TFs) formed by oxidative coupling of catechins in tea leaves during its processing. In this paper, we report the characterization of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear inflammatory model and the inhibitory effects of major black tea TFs derivatives on this inflammation. In addition, the effect on inflammatory biomarkers, such as proinflammatory cytokines and arachidonic acid metabolites, are reported as well. A single topical application of TPA to ears of CD-1 mice induced a time- and dose-dependent increase in edema as well as formation of proinflammatory cytokine proteins interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) in mouse ears. A single topical application of equimolar of black tea constituents (TF, theaflavin-3-gallate, theaflavin-3'-gallate, and theaflavin-3,3'-digallate) strongly inhibited TPA-induced edema of mouse ears. Application of TFs mixture to mouse ears 20 min prior to each TPA application once a day for 4 days inhibited TPA-induced persistent inflammation, as well as TPA-induced increase in IL-1beta and IL-6 protein levels. TFs also inhibited arachidonic acid (AA) metabolism via both cyclooxygenase (COX) and lipoxygenase pathways. This observation was substantiated by decreased amounts of AA metabolites prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels. Combined application of TF and sulindac, a nonsteroidal anti-inflammatory drug resulted a significant synergetic anti-inflammatory effect. Oral administration of TFs or the hot water extract of black tea leaves also significantly inhibited TPA-induced edema in mouse ears. In conclusion, proinflammatory cytokines, IL-1beta and IL-6, as well as the intermediated metabolites of AA, PGE2, and LTB4 are good biomarkers for inflammation. Black tea constituents, TF and its derivatives, had strongly anti-inflammatory activity in vivo which may be due to their ability to inhibit AA metabolism via lipoxygenase and COX pathways.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Biflavonoids; Catechin; Dinoprostone; Drug Synergism; Ear; Edema; Female; Gallic Acid; Inflammation; Interleukin-1; Interleukin-6; Leukotriene B4; Lipoxygenase; Mice; Prostaglandin-Endoperoxide Synthases; Sulindac; Tea; Tetradecanoylphorbol Acetate

Neutrophils serve as a vanguard of the acute innate immune response to invading pathogens. Neutrophils are also abundant at sites of autoimmune inflammation, such as the rheumatoid joint, although their pathophysiologic role is incompletely defined and relevant effector functions remain obscure. Using genetic and pharmacologic approaches in the K/BxN serum transfer model of arthritis, we find that autoantibody-driven erosive synovitis is critically reliant on the generation of leukotrienes, and more specifically on leukotriene B4 (LTB4), for disease induction as well as perpetuation. Pursuing the cellular source for this mediator, we find via reconstitution experiments that mast cells are a dispensable source of leukotrienes, whereas arthritis susceptibility can be restored to leukotriene-deficient mice by intravenous administration of wild-type neutrophils. These experiments demonstrate a nonredundant role for LTB4 in inflammatory arthritis and define a neutrophil mediator involved in orchestrating the synovial eruption.

Topics: Animals; Arthritis; Cells, Cultured; Genetic Predisposition to Disease; Inflammation; Leukotriene B4; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils

Macroscopically, the airways in primary ciliary dyskinesia (PCD) are inflamed and infected, and the eventual result is bronchiectasis. The measurement of noninvasive markers of inflammation in PCD may allow determination of mechanisms of tissue damage, and even allow monitoring of therapy. The aim of this study was to measure in exhaled breath condensate (EBC) of children with PCD the concentrations of the neutrophil chemoattractants leukotriene (LT) B4 and interleukin (IL)-8 and the marker of oxidative stress 8-isoprostane (8-IP), and to try determining whether these markers can be used to assess mechanisms of airway inflammation in these patients. Concentrations of LTB4, IL-8, and 8-IP in the EBC of 23 PCD and 11 age-matched healthy children were measured using an enzyme immunoassay (EIA). The children also performed spirometry and underwent sputum induction, the latter for differential cell count. The concentrations of 8-IP in EBC of children with stable PCD were significantly increased compared to normal controls (median, 7.8 pg/ml vs. 3.1 pg/ml; P = 0.004). There was no difference in the median concentrations of EBC LTB4 between PCD subjects and healthy controls (28 pg/ml vs. 28 pg/ml; P = 0.5). IL-8 levels were below the detection limit of the assay, and were not analyzed further. There was no correlation between concentrations of either 8-IP or LTB(4) in EBC and forced expired volume in 1 sec in PCD children. Sputum induction was successful in 83% of the subjects; the median induced sputum neutrophil count was 69% (interquartile range, 59.3-73.6). No significant correlation was found between sputum neutrophils and either EBC 8-IP or LTB4 concentrations in PCD children. This study showed that oxidative stress, as reflected by increased exhaled 8-IP concentration, is increased in PCD children. The mechanism of airway neutrophilia is unclear, but is unlikely to be related to increased production of LTB4, at least in stable PCD patients.

Topics: Adolescent; Biomarkers; Breath Tests; Cell Count; Child; Dinoprost; Female; Forced Expiratory Volume; Humans; Inflammation; Interleukin-8; Kartagener Syndrome; Leukotriene B4; Male; Neutrophils; Sputum

Primary effusion lymphoma (PEL) is a herpesvirus-8-associated lymphoproliferative disease characterized by migration of tumor cells to serous body cavities. PEL cells originate from postgerminal center B cells and share a remarkable alteration in B cell transcription factor expression and/or activation with classical Hodgkin's disease cells. Comparative analysis of gene expression by cDNA microarray of BCBL-1 cells (PEL), L-428 (classical Hodgkin's disease), and BJAB cells revealed a subset of genes that were differentially expressed in BCBL-1 cells. Among these, four genes involved in cell migration and chemotaxis were strongly up-regulated in PEL cells: leukotriene A4 (LTA4) hydrolase (LTA4H), IL-16, thrombospondin-1 (TSP-1), and selectin-P ligand (PSGL-1). Up-regulation of LTA4H was investigated at the transcriptional level. Full-length LTA4H promoter exhibited 50% higher activity in BCBL-1 cells than in BJAB or L-428 cells. Deletion analysis of the LTA4H promoter revealed a positive cis-regulatory element active only in BCBL-1 cells in the promoter proximal region located between -76 and -40 bp. Formation of a specific DNA-protein complex in this region was confirmed by EMSA. Coculture of ionophore-stimulated primary neutrophils with BCBL-1 cells leads to an increased production of LTB4 compared with coculture with BJAB and L-428 cells as measured by enzyme immunoassay, demonstrating the functional significance of LTA4H up-regulation.

Topics: Cell Line, Tumor; Enzyme Activation; Epoxide Hydrolases; Gene Expression Profiling; Hodgkin Disease; Humans; Inflammation; Interleukin-16; Leukotriene B4; Lymphoma, B-Cell; Membrane Glycoproteins; Promoter Regions, Genetic; RNA, Messenger; Thrombospondin 1; Transcription, Genetic; Up-Regulation

1. The antinociceptive effect of risedronate in experimental pain models in rats and mice was investigated in the present study. 2. Rats received zymosan intra-articularly (i.art.) into the right knee joint and the nociceptive response was assessed using the articular incapacitation test. Joint washouts were used for determining cell influx, tumour necrosis factor (TNF)-alpha and leukotriene (LT) B4 levels. 3. Mice received either zymosan (1 mg) or acetic acid (0.6%) i.p. and the nociceptive response was measured as the number of writhings between 0 and 30 min after the stimuli. Control animals received i.p. injections of saline. 4. Groups were pretreated with risedronate (5-500 microg/kg, s.c.) and compared with vehicle (saline)-treated (NT) animals. One group of rats was cotreated with the micro-opioid receptor antagonist naloxone (2 mg/kg, s.c.) prior to risedronate, followed by 1 mg zymosan i.art. 5. Risedronate, at 100 and 500 microg/kg, significantly and dose-dependently inhibited the nociceptive response in the writhings test (P < 0.05), inhibiting responses to acetic acid by 65.4 and 49.2%, respectively, and to zymosan by 72.9 and 71.9%, respectively. 6. Pretreatment with risedronate also significantly (P < 0.05) and dose-dependently inhibited the articular incapacitation in zymosan-arthritis. 7. Risedronate, at 50 microg/kg, significantly inhibited TNF-alpha release as compared with the NT group (39.4 +/- 9.8 vs 145.6 +/- 43.3 pg/mL TNF-alpha, respectively). 8. Risedronate, at 50 and 100 microg/kg, significantly inhibited LTB4 release into the joints compared with the NT group (2883.1 +/- 73.2, 1911.5 +/- 205.3 and 4709.9 +/- 237.2 pg/mL, respectively). These effects of risedronate were associated with a significant reduction in the inflammatory cell infiltration. 9. Cotreatment with risedronate and naloxone did not reverse the antinociceptive effects of risedronate in zymosan-arthritis. 10. This is the first demonstration that risedronate displays intrinsic antihypernociceptive activity. This effect is associated with reduced cell infiltration and inhibition of TNF-alpha and LTB4 release and is not linked to an endogenous opioid-release mechanism.

Topics: Acetic Acid; Analgesics; Animals; Anti-Inflammatory Agents; Arthritis, Experimental; Diphosphonates; Disease Models, Animal; Dose-Response Relationship, Drug; Etidronic Acid; Inflammation; Leukotriene B4; Male; Mice; Pain; Pain Measurement; Rats; Rats, Wistar; Risedronic Acid; Tumor Necrosis Factor-alpha; Zymosan

Omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFA) are the precursors of potent lipid mediators and play an important role in regulation of inflammation. Generally, n-6 PUFA promote inflammation whereas n-3 PUFA have antiinflammatory properties, traditionally attributed to their ability to inhibit the formation of n-6 PUFA-derived proinflammatory eicosanoids. Newly discovered resolvins and protectins are potent antiinflammatory lipid mediators derived directly from n-3 PUFA with distinct pathways of action. However, the role of the n-3 PUFA tissue status in the formation of these antiinflammatory mediators has not been addressed. Here we show that an increased n-3 PUFA tissue status in transgenic mice that endogenously biosynthesize n-3 PUFA from n-6 PUFA leads to significant formation of antiinflammatory resolvins and effective reduction in inflammation and tissue injury in colitis. The endogenous increase in n-3 PUFA and related products did not decrease n-6 PUFA-derived lipid mediators such as leukotriene B4 and prostaglandin E2. The observed inflammation protection might result from decreased NF-kappaB activity and expression of TNFalpha, inducible NO synthase, and IL-1beta, with enhanced mucoprotection probably because of the higher expression of trefoil factor 3, Toll-interacting protein, and zonula occludens-1. These results thus establish the fat-1 transgenic mouse as a new experimental model for the study of n-3 PUFA-derived lipid mediators. They add insight into the molecular mechanisms of inflammation protection afforded by n-3 PUFA through formation of resolvins and protectins other than inhibition of n-6 PUFA-derived eicosanoid formation.

Topics: Animals; Colitis; Dinoprostone; Eicosanoids; Fatty Acids, Omega-3; Inflammation; Leukotriene B4; Lipids; Mass Spectrometry; Mice; Mice, Inbred C57BL; Mice, Transgenic; Models, Chemical; NF-kappa B; Ultraviolet Rays

Licofelone is an analogue of arachidonic acid that inhibits 5-lipoxygenase (LOX), cyclooxygenase (COX)-1 and COX-2. We investigated the effects of licofelone on cardiovascular derangements and production of thromboxane (Tx)A(2) induced by the inflammatory agonist n-formyl-methionyl-leucyl-phenylalanine (fMLP) in the rabbit, in comparison with those of aspirin or rofecoxib, inhibitors of COX-1 and COX-2, respectively. In control rabbits, injection of fMLP (30 nmol/kg) in the jugular vein evokes ischemic electrocardiographic (ECG) changes in the first 1-5 min, i.e. a profound depression of the ST segment and inversion of the T wave. Simultaneously, fMLP induces bradycardia and hypotension and increases TxB(2) blood levels. All changes are transient. Licofelone (60 mg/kg/5 days, p.os) prevented fMLP-induced ECG ischemic changes in all treated animals, reverted bradycardia and hypotension, and significantly reduced TxB(2). Aspirin (10 mg/kg/5 days, p.os) prevented ischemic ECG alterations in 2 out of 5 treated animals and did not modify either bradycardia or hypotension. One rabbit died two min after fMLP. In 2 rabbits, aspirin reduced TxB(2) levels by more than 80% respect to mean control values; the remaining two rabbits produced an amount of TxB(2) similar to controls. These two rabbits also showed ischemic ECG changes. Rofecoxib (10 mg/kg/5 days, p.os) did not prevent fMLP-induced ischemic ECG alteration, bradycardia and hypotension, and did not significantly modify the increase of TxB(2). These results indicate that the capacity of licofelone to efficiently suppress TxA(2) production, is responsible for the protection from the cardiovascular derangement triggered by an inflammatory stimulus.

Topics: Acetates; Animals; Aspirin; Blood Pressure; Cyclooxygenase Inhibitors; Disease Models, Animal; Electrocardiography; Heart Rate; Inflammation; Lactones; Leukotriene B4; Lipoxygenase Inhibitors; Male; Myocardial Ischemia; N-Formylmethionine Leucyl-Phenylalanine; Pyrroles; Rabbits; Sulfones; Thromboxane A2; Time Factors

Inhaled endotoxin is known to induce airway inflammation, causing bronchial hyperreactivity.. We characterized the response to lipopolysaccharide-inhalation by measuring exhaled nitric oxide (eNO) and inflammatory mediators.. A total of 43 adult volunteers (13 asthmatics, 30 healthy controls) inhaled stepwise LPS every 30 min up to a cumulative dose of 100 microg (2.5, 10.5, 42, 45 microg). After each provocation and up to 24 h later, FEV(1) was determined; the procedure was stopped when FEV(1) declined more than 12.5%. We measured eNO, leucocytes, eosinophils, polymorphonuclear neutrophils (PMNs), C-reactive protein (CrP), lipopolysaccharide binding protein (LBP), eosinophilic cationic protein (ECP), leucotriene B4 (LTB4), thromboxane B2 (TXB2), and body temperature.. Initial eNO values were higher in asthmatics (P < 0.01), but only increased in an asthmatic subgroup. Marked differences were observed in the systemic response to LPS inhalation. Significant increases were found for CrP, LBP, and PMNs. There was no correlation between FEV(1) decrease and basal eNO levels.. Inhalation of endotoxin was followed by clinical and laboratory signs of systemic inflammation, with asthmatics responding to the challenge similar as healthy subjects. Bronchial eNO increased only temporarily in asthmatics.

Topics: Administration, Inhalation; Adult; Animals; Asthma; Biomarkers; Body Size; Body Weight; C-Reactive Protein; Eosinophils; Female; Humans; Inflammation; Leukocytes; Leukotriene B4; Leukotrienes; Lipopolysaccharides; Male; Mites; Neutrophils; Nitric Oxide Synthase Type III; Reference Values

The role of a cytosolic phospholipase A(2)-alpha (cPLA(2)-alpha) in neutrophil arachidonic acid release, platelet-activating factor (PAF) biosynthesis, NADPH oxidase activation, and bacterial killing in vitro, and the innate immune response to bacterial infection in vivo was examined. cPLA(2)-alpha activity was blocked with the specific cPLA(2)-alpha inhibitor, Pyrrolidine-1 (human cells), or by cPLA(2) -alpha gene disruption (mice). cPLA(2)-alpha inhibition or gene disruption led to complete suppression of neutrophil arachidonate release and PAF biosynthesis but had no effect on neutrophil NADPH oxidase activation, FcgammaII/III or CD11b surface expression, primary or secondary granule secretion, or phagocytosis of Escherichia coli in vitro. In contrast, cPLA(2)-alpha inhibition or gene disruption diminished neutrophil-mediated E. coli killing in vitro, which was partially rescued by exogenous arachidonic acid or PAF but not leukotriene B(4). Following intratracheal inoculation with live E. coli in vivo, pulmonary PAF biosynthesis, inflammatory cell infiltration, and clearance of E. coli were attenuated in cPLA(2)-alpha(-/-) mice compared with wild type littermates. These studies identify a novel role for cPLA(2)-alpha in the regulation of neutrophil-mediated bacterial killing and the innate immune response to bacterial infection.

Topics: Animals; Arachidonic Acid; Bronchoalveolar Lavage Fluid; CD11b Antigen; Cytosol; Dose-Response Relationship, Drug; Escherichia coli; Group IV Phospholipases A2; Humans; Inflammation; Ionomycin; Leukotriene B4; Mice; Mice, Transgenic; NADPH Oxidases; Neutrophils; Oxygen; Phagocytosis; Phospholipases A; Phospholipases A2; Platelet Activating Factor; Pneumonia; Pyrrolidines; Receptors, IgG; Time Factors; Tumor Necrosis Factor-alpha

We examined the impact of dietary fatty acid intake on lipopolysaccharide (LPS)-induced endotoxic shock. C57Bl/6J mice were fed for 6 weeks with a commercial laboratory chow (CC) or with test chows containing 7% (w/w) canola oil (CO), sesame oil (SeO), soybean oil (SO), or virgin olive oil (OO). The increase in body weight and energy consumption were similar for all diets tested. In the sixth week, mice were injected intraperitoneally with 400 microg of bacterial LPS to induce endotoxic shock. LPS induced a massive neutrophil infiltration into the peritoneal cavity and an increase in lipid body (LB) formation in leukocytes recovered from the peritoneal fluid of mice fed with CC, CO, SeO, or SO. In addition, there were increases in prostaglandin E(2) (PGE(2)), leukotriene B4 (LTB(4)), and cytokines IL-6, IL-10, and MCP-1 in peritoneal lavage, as well as in plasma TNF-alpha. In contrast, mice fed with OO exhibited reduced neutrophil accumulation and LB formation, and also had lower levels of PGE(2), LTB(4), MCP-1, and TNF-alpha. All mice fed with CC, CO, SeO, or SO died within 48 to 72 h after LPS injection. Interestingly, mice fed with the OO diet were resistant to endotoxic shock, with 60% survival at 168 h. These data indicate that intake of OO may have a beneficial role, reducing the magnitude of the inflammatory process triggered by endotoxic shock through modulation of LB formation and of the production of inflammatory mediators.

Topics: Animal Feed; Animals; Body Weight; Cell Movement; Cell Survival; Chemokine CCL2; Cytokines; Diet; Dinoprostone; Endotoxins; Escherichia coli; Fatty Acids; Fatty Acids, Monounsaturated; Female; Inflammation; Interleukin-10; Interleukin-6; Leukotriene B4; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Neutrophils; Olive Oil; Plant Oils; Rapeseed Oil; Sesame Oil; Shock, Septic; Soybean Oil; Time Factors; Tumor Necrosis Factor-alpha

The surface of the eye actively suppresses inflammation while maintaining a remarkable capacity for epithelial wound repair. Our understanding of mechanisms that balance inflammatory/reparative responses to provide effective host defense while preserving tissue function is limited, in particular, in the cornea. Lipoxin A(4) (LXA(4)) and docosahexaenoic acid-derived neuroprotectin D1 (NPD1) are lipid autacoids formed by 12/15-lipoxygenase (LOX) pathways that exhibit anti-inflammatory and neuroprotective properties. Here, we demonstrate that mouse corneas generate endogenous LXA(4) and NPD1. 12/15-LOX (Alox15) and LXA(4) receptor mRNA expression as well as LXA(4) formation were abrogated by epithelial removal and restored during wound healing. Amplification of these pathways by topical treatment with LXA(4) or NPD1 (1 microg) increased the rate of re-epithelialization (65-90%, n = 6-10, p < 0.03) and attenuated the sequelae of thermal injury. In contrast, the proinflammatory eicosanoids, LTB(4) and 12R-hydroxyeicosatrienoic acid, had no impact on corneal re-epithelialization. Epithelial removal induced a temporally defined influx of neutrophils into the stroma as well as formation of the proinflammatory chemokine KC. Topical treatment with LXA(4) and NPD1 significantly increased PMNs in the cornea while abrogating KC formation by 60%. More importantly, Alox15-deficient mice exhibited a defect in both corneal re-epithelialization and neutrophil recruitment that correlated with a 43% reduction in endogenous LXA(4) formation. Collectively, these results identify a novel action for the mouse 12/15-LOX (Alox15) and its products, LXA(4) and NPD1, in wound healing that is distinct from their well established anti-inflammatory properties.

Topics: Animals; Anti-Inflammatory Agents; Arachidonate 12-Lipoxygenase; Arachidonate 15-Lipoxygenase; Chemokines; Chromatography, High Pressure Liquid; Cornea; Docosahexaenoic Acids; Eicosanoids; Epithelial Cells; Epithelium; Gas Chromatography-Mass Spectrometry; Hot Temperature; Hydroxyeicosatetraenoic Acids; Inflammation; Leukocytes; Leukotriene B4; Lipid Metabolism; Mice; Mice, Inbred BALB C; Models, Chemical; Neutrophils; Phenotype; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Ultraviolet Rays; Wound Healing

The present study was aimed to evaluate the effect of licofelone, a dual inhibitor of cycloxygenase1/2-5-lipoxygenase against indomethacin-induced gastric damage in rats and mice in order to assess the role of leukotrienes if any, in non-steroidal anti-inflammatory drugs (NSAIDs)-induced gastrointestinal inflammation. Acute pretreatment with licofelone reversed the indomethacin-induced gastric ulceration, neutrophil adhesion in mesentery venules, neutrophil count in blood, lipid peroxides and vascularity in the stomachs of mice and rats. Further, chronic pretreatment of licofelone also prevented indomethacin-induced gastric morphological changes and cellular infiltration in mesentery venules. Moreover, acute administration of indomethacin elevated leukotriene B4 levels in gastric mucosa, which was reversed by pretreatment with licofelone The results suggest that licofelone offered gastroprotection against NSAIDs-induced gastropathy through its effect on leukotrienes and by inhibiting extravasation of neutrophils.

Topics: Acetates; Animals; Anti-Inflammatory Agents, Non-Steroidal; Anti-Ulcer Agents; Female; Humans; Indomethacin; Inflammation; Leukotriene B4; Lipid Peroxidation; Male; Mesentery; Mice; Neutrophils; Pyrroles; Rats; Stomach Ulcer; Time Factors

In the present study, we investigated the involvement of macrophage-inflammatory protein-1alpha (MIP-1alpha)[CC chemokine ligand 3 (CCL3)], MIP-1beta[CCL4], regulated on activation, normal T expressed and secreted (RANTES)[CCL5], and CC chemokine receptors (CCRs) on neutrophil migration in murine immune inflammation. Previously, we showed that ovalbumin (OVA)-triggered neutrophil migration in immunized mice depends on the sequential release of tumor necrosis factor alpha (TNF-alpha) and leukotriene B(4)(LTB(4)). Herein, we show increased mRNA expression for MIP-1alpha[CCL3], MIP-1beta[CCL4], RANTES[CCL5], and CCR1 in peritoneal cells harvested from OVA-challenged, immunized mice, as well as MIP-1alpha[CCL3] and RANTES[CCL5] but not MIP-1beta[CCL4] proteins in the peritoneal exudates. OVA-induced neutrophil migration response was muted in immunized MIP-1alpha[CCL3](-/-) mice, but it was not inhibited by treatment with antibodies against RANTES[CCL5] or MIP-1beta[CCL4]. MIP-1alpha[CCL3] mediated neutrophil migration in immunized mice through induction of TNF-alpha and LTB(4) synthesis, as these mediators were detected in the exudates harvested from OVA-challenged immunized wild-type but not MIP-1alpha[CCL3](-/-) mice; administration of MIP-1alpha[CCL3] induced a dose-dependent neutrophil migration, which was inhibited by treatment with an anti-TNF-alpha antibody in TNF receptor 1 (p55(-/-))-deficient mice or by MK 886 (a 5-lipoxygenase inhibitor); and MIP-1alpha[CCL3] failed to induce LTB(4) production in p55(-/-) mice. MIP-1alpha[CCL3] used CCR1 to promote neutrophil recruitment, as OVA or MIP-1alpha[CCL3] failed to induce neutrophil migration in CCR1(-/-) mice, in contrast to CCR5(-/-) mice. In summary, we have demonstrated that neutrophil migration observed in this model of immune inflammation is mediated by MIP-1alpha[CCL3], which via CCR1, induces the sequential release of TNF-alpha and LTB(4). Therefore, whether a similar pathway mediates neutrophil migration in human immune-inflammatory diseases, the development of specific CCR1 antagonists might have a therapeutic potential.

Topics: Animals; Antibodies; Autoimmune Diseases; Chemokine CCL3; Chemokine CCL4; Chemokine CCL5; Chemokines, CC; Chemotaxis, Leukocyte; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme Inhibitors; Inflammation; Leukotriene B4; Macrophage Inflammatory Proteins; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Ovalbumin; Receptors, CCR1; Receptors, Chemokine; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; RNA, Messenger; Signal Transduction; Tumor Necrosis Factor Decoy Receptors; Tumor Necrosis Factor-alpha; Up-Regulation

Topics: Animals; Humans; Infections; Inflammation; Leukotriene B4; Magnetic Resonance Imaging; Neoplasm Metastasis; Neoplasms; Positron-Emission Tomography; Receptor, Adenosine A1

4-(2',4'- Difluorobiphenyl-4-yl)-2-methylbutyric acid (deoxoflobufen, VUFB 19053, CAS 847475-35-8) has been developed as a new omega-biphenyl-alkanoic acid and studied in comparison with the racemic form of 4-(2',4'-difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic acid (flobufen, CAS 112344-52-2). The compounds were tested in a series of models including acute inflammation induced by carrageenan, adjuvant arthritis, in vitro inhibition of the leuktotriene B4 (LTB4) production, reaction of the graft versus the host (GVHR), production of specific antibodies against ovalbumin, peritoneal exudate formation induced by thioglycollate and phagocytosis of thioglycollate-stimulated mouse peritoneal macrophages. Deoxoflobufen exhibited strong anti-inflammatory, antiarthritic and immunomodulatory effects in most of the performed tests. Anti-inflammatory and antiarthritic effects are fully comparable with those of flobufen, however, the compound is less toxic and has apparently stronger immunomodulating effects.

Topics: Animals; Anti-Inflammatory Agents; Antibody Formation; Area Under Curve; Arthritis, Experimental; Biphenyl Compounds; Butyrates; Carrageenan; Cell Adhesion; Exudates and Transudates; Female; Graft vs Host Disease; Hypersensitivity, Delayed; Inflammation; Leukotriene B4; Macrophages; Mice; Ovalbumin; Peritonitis; Phagocytosis; Pleurisy; Rats; Structure-Activity Relationship; Thioglycolates

Studies have demonstrated that the bivalent (111)In-labeled leukotriene B4 (LTB4) antagonist DPC11870 reveals infectious and inflammatory lesions in various rabbit models. The radioactive tracer accumulates quickly at the site of infection and clears rapidly from the circulation, resulting in high-quality images. In this study, 2 new hydrazinonicotinamide (HYNIC)-conjugated compounds that are structurally related to DPC11870 were studied to further improve image quality.. A bivalent HYNIC-conjugated LTB4 antagonist (MB81) and a monovalent one (MB88) were labeled with (99m)Tc. The radiolabeled compounds were intravenously injected into New Zealand White rabbits with E. coli infection in the left thigh muscle. The imaging characteristics of both compounds were compared with those of the bivalent (111)In-labeled LTB4 antagonist.. Both (99m)Tc-labeled LTB4 antagonists revealed the abscess from 2 h after injection onward. Abscess uptake at 8 h after injection was similar for both compounds (0.22 +/- 0.08 percentage injected dose per gram [%ID/g] and 0.36 +/- 0.13%ID/g for the bivalent and monovalent compounds, respectively). However, visualization of the abscess and the quality of the images were better after injection of MB88 than after injection of either of the bivalent LTB4 antagonists. The excellent delineation of the abscess by MB88 was mainly due to the more rapid clearance of this compound from nontarget organs.. The (99m)Tc-labeled HYNIC conjugated LTB4 antagonists MB88 and MB81 revealed infectious foci in rabbits within a few hours after injection. Imaging characteristics of monovalent (99m)Tc-MB88 were superior to those of the bivalent LTB4 antagonists DPC11870 and MB81. Therefore, of the 3 LTB4 antagonists, the monovalent LTB4 antagonist MB88 is the most potent and promising agent for visualizing and evaluating infection and inflammation in patients.

Topics: Animals; Escherichia coli Infections; Female; Image Enhancement; Inflammation; Leukotriene B4; Metabolic Clearance Rate; Organ Specificity; Rabbits; Radionuclide Imaging; Radiopharmaceuticals; Technetium Compounds; Tissue Distribution

Late-phase airway hyperresponsiveness (AHR) in asthma is considered the event leading to persistent inflammation in the lungs, but the molecular mechanisms involved in this process are poorly understood.. To examine the role of TNF-alpha in the development of a late AHR and airway inflammation in asthma.. We established a murine model of asthma with not only biphasic AHR to methacholine but also airway eosinophilia. The effect of TNF-alpha blockade was determined by using anti-TNF-alpha antibody and TNF-alpha knockout mice. Cytosolic phospholipase A(2) (cPLA(2)) mRNA expression and activity were assessed by using RT-PCR and 1-stearoyl-2-[1-(14)C] arachidonyl-sn-glycero-3-phosphocholine as the substrate, respectively.. TNF-alpha blockade resulted in significant inhibition of the late AHR without affecting the early AHR, and reduction in airway eosinophilia and inflammation. cPLA(2) activity was increased in asthmatic lungs in a TNF-alpha-dependent way, and cPLA(2) inhibitor blocked late AHR and airway eosinophilia. TNF-alpha also stimulated the synthesis of cPLA(2) metabolites such as leukotriene B(4) and platelet-activating factor in the airway. Specific inhibitors of cPLA(2) metabolites inhibited the late AHR and airway eosinophilia.. TNF-alpha is the proximal key cytokine capable of developing late-phase AHR and subsequent airway inflammation through expression/activation of cPLA(2).

Topics: Animals; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Bronchoconstrictor Agents; Cytosol; Disease Models, Animal; Enzyme Activation; Histamine; Inflammation; Leukotriene B4; Male; Methacholine Chloride; Mice; Mice, Inbred BALB C; Mice, Knockout; Phospholipases A; Platelet Activating Factor; Pulmonary Eosinophilia; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tumor Necrosis Factor-alpha

The peroxisome proliferator-activated receptor system is exciting much interest as a novel point of therapeutic intervention in inflammation. Here, the effect of a peroxisome proliferator-activated receptor alpha agonist, [4-chloro-6-(2,3-xylidine)-pyrimidinylthio]acetic acid (Wy14,643), was examined in arachidonic acid-induced murine ear inflammation. 3-[1-(4-Chlorobenzyl)-3-t-butyl-thio-5-isopropylindol-2-yl]-2,2-dimethylpropanoic acid (MK886, a 5-lipoxygenase inhibitor) and indomethacin (a cyclo-oxygenase inhibitor) were used as reference compounds. Wy14,643 dose dependently inhibited ear swelling and polymorphonuclear leukocyte influx, as did MK886, associated with reduced tissue leukotriene B4 but not prostaglandin E2 levels. Unlike MK886, Wy14,643 did not inhibit ex vivo leukotriene B4 production. However, Wy14,643, but not MK886, induced peroxisomal enzyme activity. Indomethacin was less effective, though tissue prostaglandin E2 but not leukotriene B4 levels were reduced. Again, unlike indomethacin, Wy14,643 did not reduce ex vivo prostaglandin E2 production. However, indomethacin did increase peroxisomal enzyme activity but to a lesser extent than Wy14,643. This study demonstrates that peroxisome proliferator-activated receptor alpha activation can inhibit arachidonic acid-induced inflammation in part by enhancing degradation of leukotriene B4.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents; Arachidonate 5-Lipoxygenase; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Ear, External; Edema; Female; Indoles; Indomethacin; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Mice; Neutrophils; Palmitoyl Coenzyme A; Peroxisomes; PPAR alpha; Prostaglandin-Endoperoxide Synthases; Pyrimidines

Neonatal-onset multisystem inflammatory disease (NOMID)/chronic infantile neurologic, cutaneous, and articular syndrome is an autoinflammatory disease characterized by urticarial rash, arthropathy, and central nervous system inflammation.. To describe a 13-year-old girl with overlapping symptoms of NOMID and Muckle-Wells syndrome who has a mutation in cryopyrin (NALP3).. We examined neutrophil migration using transwell assay and time-lapse videomicroscopy. We also examined p38 mitogen-activated protein kinase (MAPK) activation in patient and control neutrophils using Western blot analysis.. Neutrophil defects in chemotactic migration were found to a variety of chemoattractants, including interleukin 8, N-formyl-methionyl-leucyl-phenylalanine, complement C5a, and leukotriene B4. Her neutrophils exhibited elevated basal and stimulated p38 MAPK activation in response to interleukin 8, N-formyl-methionyl-leucyl-phenylalanine, complement C5a, and leukotriene B4.. This study is the first, to our knowledge, to demonstrate defects in neutrophil chemotaxis and p38 MAPK signaling in a patient with NOMID and Muckle-Wells syndrome and a cryopyrin mutation.

Topics: Adolescent; Carrier Proteins; Chemotaxis, Leukocyte; Complement C5a; Familial Mediterranean Fever; Female; Humans; Inflammation; Interleukin-8; Leukotriene B4; Mutation; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; NLR Family, Pyrin Domain-Containing 3 Protein; p38 Mitogen-Activated Protein Kinases

The cellular and molecular mechanisms for the development of tendinopathy are not clear, but inflammatory mediators produced by tendon fibroblasts in response to repetitive mechanical loading may be an important factor.. (1) Cyclic stretching of tendon fibroblasts affects the production of leukotriene B(4) and the expression of 5-lipoxygenase; and (2) the production level of leukotriene B(4) is inversely related to that of prostaglandin E(2).. Controlled laboratory study.. Human patellar tendon fibroblasts were uniaxially stretched in the presence of indomethacin (25 micro M) or MK-886 (10 micro M). After stretching for 4 hours, followed by 4 hours rest, levels of prostaglandin E(2), leukotriene B(4), and expression of 5-lipoxygenase were measured.. Stretched tendon fibroblasts increased the levels of leukotriene B(4) but did not appreciably change the expression of 5-lipoxygenase. Indomethacin decreased the cellular production of prostaglandin E(2) but caused increased leukotriene B(4) levels. MK-886 caused decreased production of leukotriene B(4) but increased production of prostaglandin E(2).. Cyclic stretching of human tendon fibroblasts increases the production of prostaglandin E(2) and leukotriene B(4). Blocking prostaglandin E(2) production leads to increased leukotriene B(4) levels and vice versa.. The use of nonsteroidal anti-inflammatory drugs for the treatment of tendon inflammation might increase the levels of leukotriene B(4) within the tendon, potentially contributing to the development of tendinopathy.

Topics: Adult; Anti-Inflammatory Agents, Non-Steroidal; Arachidonate 5-Lipoxygenase; Bicycling; Cell Culture Techniques; Dinoprostone; Fibroblasts; Humans; Indoles; Indomethacin; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Tendons; Tensile Strength

Aggregation of receptors for immunoglobulin G (FcgammaRs) on myeloid cells activates a series of events that are key in the inflammatory response and that can ultimately lead to targeted cell killing by antibody-directed cellular cytotoxicity. Generation of lipid-derived proinflammatory mediators is an important component of the integrated cellular response mediated by receptors for the constant region of immunoglobulins (Fc). We have demonstrated previously that, in interferon-gamma-primed U937 cells, the high affinity receptor for IgG, FcgammaRI, is coupled to a novel intracellular signaling pathway that involves the sequential activation of phospholipase D, sphingosine kinase, calcium transients, and protein kinase C isoforms, leading to the activation of the NADPH-oxidative burst. Here, we investigate the nature of the phospholipase that regulates arachidonic acid and eicosanoid production. Our data show that FcgammaRI couples to iPLA(2)beta for the release of arachidonic acid and the generation of leukotriene B(4) and prostaglandin E(2). Activation of iPLA(2)beta was protein kinase C-dependent; on the other hand, platelet-activating factor triggered cPLA(2)alpha by means of the mitogen-activated protein kinase pathway. These studies demonstrate that intracellular PLA(2)s can be selectively regulated by different stimuli and suggest a critical role for iPLA(2)beta in the intracellular signaling cascades initiated by FcgammaRI and its functional role in the generation of key inflammatory mediators.

Topics: Arachidonic Acid; Blotting, Western; Calcium; Dinoprostone; Eicosanoids; Electrophoresis, Polyacrylamide Gel; Enzyme Activation; Group VI Phospholipases A2; Humans; Inflammation; Leukotriene B4; Lipid Metabolism; Lipids; MAP Kinase Signaling System; Microscopy, Fluorescence; Monocytes; NADP; Phospholipase D; Phospholipases A; Phosphorylation; Precipitin Tests; Protein Isoforms; Protein Kinase C; Protein Transport; Receptors, IgG; Respiratory Burst; Signal Transduction; Time Factors; U937 Cells

Chemoattractant receptor-homologous molecule expressed on Th2 lymphocytes, CRTH2, is a cognate receptor for prostaglandin (PG) D(2) and, in humans, is suggested to play a functional role in Th2-dependent allergic inflammation. While peripheral blood leukocytes expressing high levels of surface CRTH2 have been detected in disease, little is known of the functional significance of CRTH2 in disease etiology. We have utilized a Th2-dependent murine model of FITC-induced contact hypersensitivity to assess the role, if any, CRTH2-PGD(2) may play in the elicitation or maintenance of such pathobiology. Expression of both PGD(2) and CRTH2 in lesional skin was paralleled by the release of the chemoattractants LTB(4) and the chemokine KC, as well as a profuse dermal neutrophilic and eosinophilic infiltrate, closely paralleling the acute inflammatory pathology observed in human atopic dermatitis. A small molecule CRTH2 antagonist, but not a selective PGD(2)R (DP) receptor antagonist, was able to completely abrogate these responses. Inflammatory cascades mediated by CRTH2 ligation may therefore represent an important early step in the elicitation and maintenance of Th2-dependent skin inflammation.

Topics: Animals; Carbazoles; Chemokine CXCL1; Chemokines; Chemokines, CXC; Cytokines; Dermatitis, Allergic Contact; Dermatitis, Atopic; Eosinophils; Female; Inflammation; Leukotriene B4; Mice; Mice, Inbred BALB C; Neutrophil Activation; Neutrophils; Platelet Aggregation Inhibitors; Prostaglandin D2; Receptors, Immunologic; Receptors, Prostaglandin; Signal Transduction; Sulfonamides; Th2 Cells

The role of 5-lipoxygenase (5-LOX) in the pathophysiology of renal ischemia/reperfusion (I/R) injury is not known. Here we investigate the effects of 1) the 5-LOX inhibitor zileuton and 2) 5-LOX gene knockout (5-LOX(-/-)) mice on renal dysfunction and injury caused by I/R of the kidney in mice. Wild-type mice treated with zileuton (3 mg/kg i.v.) or 5-LOX(-/-) mice were subjected to bilateral renal artery occlusion (30 min) followed by reperfusion (24 h). Plasma urea, creatinine, and aspartate aminotransferase (AST) were measured as markers of renal dysfunction and reperfusion injury. Kidneys were used for histological evaluation of renal injury. Renal myeloperoxidase activity was measured and used as an indicator of polymorphonuclear leukocyte (PMN) infiltration and renal expression of intercellular adhesion molecule-1 (ICAM-1) was determined using immunohistochemistry. Administration of zileuton before I/R significantly reduced the degree of renal dysfunction (urea, creatinine) and injury (AST, histology). In addition, zileuton reduced the expression of ICAM-1 and the associated PMN infiltration caused by I/R of the mouse kidney. Compared with wild-type mice, the degree of renal dysfunction, injury, and inflammation caused by I/R in 5-LOX(-/-) mice was also significantly reduced, confirming the pathophysiological role of 5-LOX in the development of renal I/R injury. We propose that 1) endogenous 5-LOX metabolites enhance the degree of renal injury, dysfunction, and inflammation caused by I/R of the kidney by promoting the expression of adhesion molecules, and 2) inhibitors of 5-LOX may be useful in the treatment of conditions associated with I/R of the kidney.

Topics: Animals; Arachidonate 5-Lipoxygenase; Disease Models, Animal; Hydroxyurea; Inflammation; Intercellular Adhesion Molecule-1; Ischemia; Kidney Diseases; Leukotriene B4; Lipoxygenase Inhibitors; Mice; Mice, Knockout; Neutrophils; Peroxidase; Reperfusion Injury

Epidemiologic studies suggest increased asthma prevalence in obese subjects. However, the relation between obesity and airway inflammation remains unclear. This cross-sectional study aims to investigate the relation between obesity indices and exhaled nitric oxide (ENO) and leukotriene B(4) (LTB(4)) in children with asthma. Asthmatic patients aged 7-18 yr old were recruited. Weight-for-height Z score was calculated from anthropometry. ENO was measured by online single-breath method using a chemiluminescence analyzer, whereas LTB(4) concentrations in exhaled breath condensate (EBC) were quantified using competitive enzyme immunoassay. Ninety-two asthmatics and 23 controls were recruited. The mean ENO and LTB(4) concentrations in EBC were higher in asthmatic patients (87 p.p.b. and 40.5 pg/ml) than controls (25 p.p.b. and 18.7 pg/ml) (p < 0.0001 for both). Obesity, as defined by weight >120% median weight-for-height, was not associated with any alteration in ENO or LTB(4) concentrations in patients with asthma. Besides, these inflammatory markers did not differ between asthmatics in the highest and lowest quartiles of weight-for-height Z score. On multivariate analysis, ENO showed significant correlation with age (beta = 0.511, p < 0.0001), peripheral blood eosinophil count (beta = 0.222, p = 0.019), plasma total IgE concentration (beta = 0.187, p = 0.050) and forced expiratory volume in 1-s (FEV(1); beta = -0.221, p = 0.014). None of the factors was associated with LTB(4) concentration in EBC. In conclusion, ENO and LTB(4) concentration in EBC are increased in childhood asthma. However, these inflammatory markers did not differ between obese and non-obese children with asthma.

Topics: Adolescent; Asthma; Breath Tests; Child; Cross-Sectional Studies; Female; Humans; Inflammation; Leukotriene B4; Lung; Male; Nitric Oxide; Obesity; Respiratory Function Tests

Neutrophil migration to an infectious focus is essential for control and resolution of infection. Early studies demonstrated that the failure of such migration is observed in lethal sepsis induced by cecal ligation and puncture (L-CLP), whereas intense neutrophil migration is seen in sublethal CLP (SL-CLP). In this study, we found that inhibition of synthesis of prostaglandins or leukotriene B4 (LTB4) did not modify the failure of neutrophil migration or the survival rate of L-CLP mice. In addition, pretreatment of L-CLP mice with a platelet activating factor (PAF) receptor antagonist (UK74505), despite not interfering with the failure process, significantly increased (33%) the survival rate of the animals. Inhibitors of prostaglandin synthesis (indomethacin and meloxican) and UK74505 did not modify the neutrophil migration observed in SL-CLP. On the other hand, the blockade of LTB4 synthesis (MK886, a 5-lipoxygenase-activating protein inhibitor) or of its receptors (CP-105,696) resulted in reduced neutrophil migration to the peritoneal cavity in SL-CLP mice (62% and 60%, respectively), a consequent increase in the number of bacteria in the inflammatory focus, and a reduced survival rate of the animals (43% and 38%, respectively). Both SL-CLP and L-CLP animals presented significant levels of LTB4 in the peritoneal exudate (3- and 8-fold higher than sham group, respectively) and these were reduced by the pretreatment of mice with LTB4 inhibitors. In conclusion, our results suggest that LTB4, but not prostaglandins or PAF, is an important chemoattractant involved in neutrophil recruitment to infection sites in SL-CLP, a crucial event in confining the invading pathogens to a restricted area. However, in circumstances in which the infection turns to a lethal sepsis, LTB4 is not involved in the observed failure of neutrophil migration to the infectious focus.

Topics: Animals; Cecum; Cell Movement; Dihydropyridines; Eicosanoids; Imidazoles; Indoles; Inflammation; Leukotriene B4; Leukotrienes; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred C57BL; Neutrophils; Peritoneum; Platelet Activating Factor; Prostaglandins; Time Factors; Wounds, Penetrating

Six acetophenones (1-6) and one gamma-pyrone (7), previously isolated from Helichrysum italicum, were tested for their ability to inhibit enzymatic and non-enzymatic lipid peroxidation, the stable 1,1-diphenyl-2-pycryl-hydrazyl free radical, superoxide scavenging and arachidonic acid metabolism. In addition, they were studied in different experimental models such as the chronic inflammation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA), the phospholipase A(2)-induced mouse paw oedema test, the carrageenan-induced mouse paw oedema test, and the writhing induced by acetic acid in the mouse. Of the assayed compounds, only 1 inhibited enzymatic lipid peroxidation but had no effect on non-enzymatic lipid peroxidation. None of them scavenged the superoxide radical. Study of the inhibition of arachidonic acid metabolism demonstrated that 1 was an inhibitor of both cyclooxygenase and 5-lipoxygenase, whereas 2 was a selective inhibitor of 5-lipoxygenase. In the assay of phospholipase A(2)-induced mouse paw oedema, the gamma-pyrone derivative inhibited oedema formation, showing a similar profile to that obtained with cyproheptadine. The acetophenones were effective at 30 and 60 min. In the carrageenan test, acetophenone 1 gave the best results and had analgesic effects in the acetic acid writhing test. In conclusion acetophenone 1 (4-hydroxy-3-(3-methyl-2-butenyl)acetophenone) is a new dual inhibitor of arachidonate metabolism, and could be a useful tool for obtaining anti-inflammatory and analgesic drugs.

Topics: Acetophenones; Analgesics; Animals; Arachidonic Acid; Carrageenan; Dose-Response Relationship, Drug; Ear; Edema; Female; Free Radicals; Glucosides; Helichrysum; Hindlimb; Inflammation; Leukotriene B4; Lipid Peroxidation; Mice; Neutrophils; Peroxidase; Phospholipases A; Plant Extracts; Rats; Rats, Wistar; Tetradecanoylphorbol Acetate

Moderate consumption of red wine has been shown to exert cardioprotection against ischemia/reperfusion. Because oxidant-dependent leukocyte infiltration plays a critical role in ischemia/reperfusion-induced tissue injury, we hypothesized that resveratrol, a red wine constituent polyphenol would attenuate postischemic leukocyte recruitment and subsequent endothelial dysfunction. Intravital microscopic approaches were used to quantify leukocyte/endothelial cell interactions and venular protein leakage in rat mesenteries exposed to either 20 min ischemia and 60 min reperfusion (I/R), oxidants generated by the reaction of hypoxanthine and xanthine oxidase (HX/XO), platelet-activating factor (PAF), or leukotriene B4 (LTB4). I/R or HX/HX produced marked increases in the number of adherent (LA) and emigrated (LE) leukocytes, which were associated with significant increases in venular albumin leakage (VAL). Intravenous administration of resveratrol or superoxide dismutase (SOD) attenuated these increases in LA, LE, and VAL. Superfusion of the mesentery with PAF or LTB4 also markedly increased LA, LE, and VAL. While resveratrol attenuated the proinflammatory effects of PAF, LTB4-induced changes were not affected by resveratrol. Resveratrol prevents leukocyte recruitment and endothelial barrier disruption induced by a number of superoxide-dependent proinflammatory stimuli, including I/R, HX/XO, or PAF. These salutary effects appear to be related to the antioxidant properties of resveratrol and contribute to the cardioprotective actions associated with consumption of red wine.

Topics: Animals; Antioxidants; Cell Adhesion; Flavonoids; Free Radicals; Hypoxanthine; Inflammation; Leukocytes; Leukotriene B4; Male; Oxidants; Phenols; Platelet Activating Factor; Polyphenols; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Resveratrol; Stilbenes; Superoxide Dismutase; Superoxides; Time Factors; Xanthine Oxidase

Signaling pathways instrumental in the temporal and spatial progression of acute inflammation toward resolution are of wide interest. Here a transgenic mouse with myeloid-selective expression of human lipoxin A4 receptor (hALX) was prepared and used to evaluate in vivo the effect of hALX expression. hALX-transfected HEK293 cells transmitted LXA4 signals that inhibit TNFalpha-induced NFkappaB activation. Transgenic FvB mice were generated by DNA injections of a 3.8 kb transgene consisting of the full-length hALX cDNA driven by a fragment of the hCD11b promoter. When topically challenged via dermal ear skin, hALX transgenic mice gave attenuated neutrophil infiltration (approximately 80% reduction) in response to leukotriene B4 (LTB4) plus prostaglandin E2 (PGE2) as well as approximately 50% reduction in PMN infiltrates (P<0.02) to receptor-bypass inflammation evoked by phorbol ester. The hALX transgenic mice gave markedly decreased PMN infiltrates to the peritoneum with zymosan and altered the dynamics of this response. Transgenic hALX mice displayed increased sensitivity with >50% reduction in PMN infiltrates to suboptimal doses (10 ng/mouse) of the ligand lipoxin A4 stable analog compared with <10% reduction of PMN in nontransgenic littermates. Soluble mediators generated within the local inflammatory milieu of hALX mice showed diminished ability to activate the proinflammatory transcription factor NFkappaB. Analyses of the lipid-derived mediators from exudates using LC-MS tandem mass spectroscopy indicated an altered profile in hALX transgenic mice that included lower levels of LTB4 and increased amounts of lipoxin A4 compared with nontransgenic littermates. Together these results demonstrate a gain-of-function with hALX transgenic mouse and indicate that ALX is a key receptor and sensor in formation of acute exudates and their resolution.

Topics: 3T3 Cells; Animals; Cell Line; Chromatography, Liquid; Dinoprostone; Female; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; Lipoxins; Male; Mass Spectrometry; Mice; Mice, Transgenic; Neutrophil Infiltration; NF-kappa B; Peritoneum; Peritonitis; Plasmids; Receptors, Cell Surface; Receptors, Formyl Peptide; Receptors, Lipoxin; Skin; Transfection; Tumor Necrosis Factor-alpha; Zymosan

Gamma-tocopherol (gammaT), the major form of vitamin E in U.S. diets, and its physiological metabolite 2, 7, 8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman (gamma-CEHC), in contrast to alpha-tocopherol (alphaT), the primary vitamin E in supplements, inhibit cyclooxygenase-catalyzed synthesis of prostaglandin E2 (PGE2) in activated macrophages and epithelial cells. Here we report that in carrageenan-induced inflammation in male Wistar rats, administration of gammaT (33 or 100 mg/kg) and gamma-CEHC (2 mg/pouch), but not alphaT (33 mg/kg), significantly reduced PGE2 synthesis at the site of inflammation. gammaT, but not alphaT, significantly inhibited the formation of leukotriene B4, a potent chemotactic agent synthesized by the 5-lipoxygenase of neutrophils. Although gammaT had no effect on neutrophil infiltration, it significantly attenuated the partial loss of food consumption caused by inflammation-associated discomfort. Administration of gammaT led consistently to a significant reduction of inflammation-mediated increase in 8-isoprostane, a biomarker of lipid peroxidation. gammaT at 100 mg/kg reduced TNF-alpha (65%;P=0.069), total nitrate/nitrite (40%;P=0.1), and lactate dehydrogenase activity (30%;P=0.067). Collectively, gammaT inhibits proinflammatory PGE2 and LTB4, decreases TNF-alpha, and attenuates inflammation-mediated damage. These findings provide strong evidence that gammaT shows anti-inflammatory activities in vivo that may be important for human disease prevention and therapy.

Topics: alpha-Tocopherol; Animals; Antioxidants; Carrageenan; Chromans; Dinoprostone; Dose-Response Relationship, Drug; Eating; Eicosanoids; Exudates and Transudates; gamma-Tocopherol; Inflammation; Leukotriene B4; Lipid Peroxidation; Male; Neutrophil Infiltration; Nitrates; Nitrites; Propionates; Rats; Rats, Wistar; Tumor Necrosis Factor-alpha

A new lipidic acid-amido ether derivative (LAAE-14) able to reduce dose-dependently the calcium increases mediated either by calcium ionophore ionomycin, by the endoplasmic reticular Ca(2+)-ATPase inhibitor thapsigargin, or by the chemotactic tripeptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), in human neutrophils as well as in murine peritoneal macrophages, but not ATP, has been evaluated as a potential anti-inflammatory drug. This compound attenuated leukocyte activation by means of its inhibitory effect on the respiratory burst elicited in both types of cells by 12-O-tetradecanoyl phorbol 13-acetate, by inhibition of the degranulation process induced by cytochalasin B+fMLP or cytochalasin B+platelet activating factor, as well as by reduction of leukotriene B(4) synthesis induced by the calcium ionophore A23187. In addition, in zymosan-stimulated mouse peritoneal macrophages LAAE-14 caused a potent inhibition of nitrite and prostaglandin E(2) production. This compound exerted acute and chronic anti-inflammatory effects by oral route, that may be related with several mechanisms such as attenuation of leukocyte activation, inhibition of inducible nitric oxide synthase, cyclo-oxygenase-2 and cytosolic phospholipase A(2) expression as well as reduction in tumour necrosis factor-alpha production. Its anti-inflammatory profile is clearly correlated with its behavior as inhibitor of intracellular calcium mobilization. The profile and potency of this compound may have relevance for the inhibition of the inflammatory response at different levels and may represent a new approach to the development of new anti-inflammatory drugs.

Topics: Acute Disease; Animals; Arthritis, Experimental; Calcium; Carrageenan; Cell Movement; Chronic Disease; Dinoprostone; Disease Models, Animal; Edema; Humans; Inflammation; Leukotriene B4; Luminescent Measurements; Macrophages, Peritoneal; Mice; Neutrophils; Nitrites; Pancreatic Elastase; Rats; Tumor Necrosis Factor-alpha; Zymosan

Most studies investigating the pathophysiological processes taking place inside an experimental burn wound use in vitro techniques, which only allow for fragmented measurements of the actual and complex processes occurring inside a burn wound in vivo. In the present study, which used a recently developed in vivo technique in the rat, a full-thickness burn was induced and resulted in the formation of a subcutaneous gelatinous edema with distinct borders to the surrounding connective tissue and free communication with the systemic circulation allowing it to be easily separated for further analysis. In the present study, we investigated the effects of topical local anaesthetics (EMLA) on the inflammatory cascade of a burn wound in vivo. Results showed significantly higher myeloperoxidase (MPO) levels in EMLA-treated burned animals (P<0.01) versus placebo-treated burned controls. EMLA treatment induced a significant inhibition of the synthesis of leukotrien B(4) (LTB(4)) (P<0.001), prostaglandin E(1) (PGE(1)) (P<0.001), prostaglandin E(2) (PGE(2)) (P<0.001) and thromboxane B(2) (TXB(2)) (P<0.001) versus control, while free radical formation did not differ significantly between EMLA-treated and control animals. In conclusion, topical local anaesthetics significantly inhibit the release of several mediators known to take important part in the pathophysiological events ensuing a burn injury, such as activation of pain mechanisms (PGE), oedema formation (LTB), and postburn ischemia (TXB). The increased numbers of leukocytes (MPO) in the burn wound induced by topical local anaesthetic treatment could suggest increased influx and/or increased viability of leukocytes postburn.

Topics: Administration, Topical; Anesthetics, Local; Animals; Burns; Free Radicals; Inflammation; Leukotriene B4; Lidocaine; Lidocaine, Prilocaine Drug Combination; Male; Models, Animal; Peroxidase; Prilocaine; Prostaglandins E; Rats; Rats, Sprague-Dawley; Thromboxane B2

Recognition of pathogens by immune cells initiates the release of numerous signaling molecules, including cytokines and eicosanoids. Here, we describe a simple procedure by which eicosanoids such as prostaglandin E(2) (PGE(2)), leukotriene B(4) (LTB(4)) and thromboxane B(2) (TxB(2)) can be measured using commercial enzyme immunoassays (EIAs) in the supernatant of whole blood stimulated with inflammatory stimuli. This is illustrated for numerous stimuli. The kinetics by which lipopolysaccharide (LPS) induces cyclooxygenase (COX)-2 expression in this setup were determined by quantitative reverse transcription polymerase chain reaction (RT-PCR). The eicosanoid response of the blood of 160 healthy volunteers to 1 microg/ml LPS was measured. To determine whether the action of a drug in vivo is represented ex vivo in the eicosanoid response of blood, one volunteer took a standard dose of a number of commercially available cyclooxygenase inhibitors on different days and the eicosanoid response of his blood to LPS was determined before ingestion as well as 2 and 6 h afterwards. The efficacy of the different pharmaceuticals on cyclooxygenase but not lipoxygenase products or cytokines could be monitored ex vivo. Similarly, ex vivo eicosanoid release was measured in blood from 10 volunteers who had taken 50 mg flurbiprofen. The method described extends approaches for studying whole blood cytokine release to the lipid mediators formed from arachidonic acid. These important signaling molecules represent targets for pharmacological intervention, which can now be monitored in vitro, as well as ex vivo employing the same model. Furthermore, the assay could be used to characterize the immune status of patient groups or to monitor the course of disease.

Topics: Adult; Anti-Inflammatory Agents, Non-Steroidal; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Dinoprostone; Humans; Immunoenzyme Techniques; Inflammation; Isoenzymes; Kinetics; Leukotriene B4; Lipopolysaccharides; Lipoxygenase Inhibitors; Male; Membrane Proteins; Prostaglandin-Endoperoxide Synthases; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Thromboxane B2

Heme oxygenase-1 (HO-1) is part of the integrated response to oxidative stress. This enzyme may exert anti-inflammatory effects in some animal models, although the precise mechanisms are not fully understood. We have examined the role of HO-1 in the inflammatory response induced by zymosan in the mouse air pouch. Zymosan administration induced HO-1 protein expression in leukocytes migrating to exudates, with maximal levels in the late phase of this response (24-48 h). This was accompanied by ferritin induction and bilirubin accumulation, indicating that this enzyme is active in our model. HO-1 expression by zymosan treatment was partly reduced by aminoguanidine, suggesting the participation of endogenous nitric oxide in the mechanisms leading to HO-1 synthesis in the zymosan-injected mouse air pouch. Up-regulation of HO-1 by hemin administration resulted in inhibition of nitric-oxide synthase-2 activity, cellular infiltration into the air pouch exudate, and plasmatic exudation. Leukotriene B4 levels in exudates were significantly decreased in the early phase of this response (4 h), whereas interleukin-1beta and tumor necrosis factor-alpha were inhibited at all time points. Inhibition of HO-1 activity by zinc protoporphyrin IX prevented most of the effects caused by hemin administration. Our results indicate that HO-1 exerts anti-inflammatory effects on the response to zymosan in the mouse air pouch and support a role for this enzyme in the modulation of inflammatory processes.

Topics: Animals; Bilirubin; Blotting, Western; Cell Count; Cell Division; Cytokines; Dinoprostone; Eicosanoids; Exudates and Transudates; Female; Flow Cytometry; Heme Oxygenase (Decyclizing); Heme Oxygenase-1; Hemin; Inflammation; Interleukin-1; Leukotriene B4; Macrophages; Membrane Proteins; Mice; Phagocytosis; Tumor Necrosis Factor-alpha; Up-Regulation; Zymosan

Directed migration of polymorphonuclear neutrophils (PMN) is required for adequate host defense against invading organisms and leukotriene B(4) (LTB(4)) is one of the most potent PMN chemoattractants. LTB(4) exerts its action via binding to BLT1, a G protein-coupled receptor. G protein-coupled receptors are phosphorylated by G protein-coupled receptor kinases (GRK) in an agonist-dependent manner, resulting in receptor desensitization. Recently, it has been shown that the human BLT1 is a substrate for GRK6. To investigate the physiological importance of GRK6 for inflammation and LTB(4) signaling in PMN, we used GRK6-deficient mice. The acute inflammatory response (ear swelling and influx of PMN into the ear) after topical application of arachidonic acid was significantly increased in GRK6(-/-) mice. In vitro, GRK6(-/-) PMN showed increased chemokinetic and chemotactic responses to LTB(4). GRK6(-/-) PMN respond to LTB(4) with a prolonged increase in intracellular calcium and prolonged actin polymerization, suggesting impaired LTB(4) receptor desensitization in the absence of GRK6. However, pre-exposure to LTB(4) renders both GRK6(-/-) as well as wild-type PMN refractory to restimulation with LTB(4), indicating that the presence of GRK6 is not required for this process to occur. In conclusion, GRK6 deficiency leads to prolonged BLT1 signaling and increased neutrophil migration.

Topics: Actins; Acute Disease; Administration, Topical; Animals; Arachidonic Acid; Calcium Signaling; Chemotaxis, Leukocyte; Ear, External; Edema; G-Protein-Coupled Receptor Kinases; Inflammation; Leukotriene B4; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Protein Serine-Threonine Kinases; Receptors, G-Protein-Coupled; Signal Transduction; Up-Regulation

Lipoxins and 15-epi-lipoxins are counter-regulatory lipid mediators that modulate leukocyte trafficking and promote the resolution of inflammation. To assess the potential of lipoxins as novel anti-inflammatory agents, a stable 15-epi-lipoxin A(4) analog, 15-epi-16-p-fluorophenoxy-lipoxin A(4) methyl ester (ATLa), was synthesized by total organic synthesis and examined for efficacy relative to a potent leukotriene B(4) (LTB(4)) receptor antagonist (LTB(4)R-Ant) and the clinically used topical glucocorticoid methylprednisolone aceponate. In vitro, ATLa was 100-fold more potent than LTB(4)R-Ant for inhibiting neutrophil chemotaxis and trans-epithelial cell migration induced by fMLP, but was approximately 10-fold less potent than the LTB(4)R-Ant in blocking responses to LTB(4). A broad panel of cutaneous inflammation models that display pathological aspects of psoriasis, atopic dermatitis, and allergic contact dermatitis was used to directly compare the topical efficacy of ATLa with that of LTB(4)R-Ant and methylprednisolone aceponate. ATLa was efficacious in all models tested: LTB(4)/Iloprost-, calcium ionophore-, croton oil-, and mezerein-induced inflammation and trimellitic anhydride-induced allergic delayed-type hypersensitivity. ATLa was efficacious in mouse and guinea pig skin inflammation models, exhibiting dose-dependent effects on edema, neutrophil or eosinophil infiltration, and epidermal hyperproliferation. We conclude that the LXA(4) and aspirin-triggered LXA(4) pathways play key anti-inflammatory roles in vivo. Moreover, these results suggest that ATLa and related LXA(4) analogs may have broad therapeutic potential in inflammatory disorders and could provide an alternative to corticosteroids in certain clinical settings.

Topics: Administration, Cutaneous; Animals; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Calcimycin; Cell Movement; Chemotaxis, Leukocyte; Croton Oil; Disease Models, Animal; Diterpenes; Female; Guinea Pigs; Humans; Hydroxyeicosatetraenoic Acids; Hypersensitivity, Delayed; Iloprost; Inflammation; Leukotriene B4; Lipoxins; Mice; Phthalic Anhydrides; Skin; Terpenes

Human esophageal adenocarcinoma (EAC) develops in a sequence from gastroesophageal reflux disease (GERD), columnar-lined esophagus (CLE), dysplasia, and eventually to EAC. We established a rat surgical EAC model with esophagogastroduodenal anastomosis (EGDA) to mimic the staged process of esophageal adenocarcinogenesis. Profiling of the AA metabolites with mass spectrometry showed that prostaglandin E2 (PGE2), leukotriene B4 (LTB4), 15-hydroeicosatetraenoic acid (HETE), 12-HETE, 8-HETE and 5-HETE all increased at the esophagoduodenal junction after EGDA as compared with the proximal esophagus, with PGE2 as the major metabolite. Consistent with this profile, cyclooxygenase 2 (Cox2) was overexpressed in the basal cell layer of esophageal squamous epithelium, CLE cells and EAC tumor cells of the EGDA rats, as compared with the normal esophageal epithelium. Sulindac (a Cox inhibitor), nordihydroguaiaretic acid (NDGA, a lipoxygenase inhibitor) and alpha-difluoromethylornithine (DFMO, an ornithine decarboxylase inhibitor) were tested for their possible inhibitory actions against the formation of EAC in the rat EGDA model. In a short-term study (for 4 weeks after surgery), dietary administration of both sulindac (300 and 600 p.p.m.) and NDGA (100 p.p.m.) effectively reduced the EGDA-induced inflammation. In a long-term chemoprevention study (for 40 weeks after surgery), 300 p.p.m. sulindac, alone or in combination with 100 p.p.m. NDGA or 0.5% DFMO, decreased the tumor incidence from 57.7 to 26.9%, or 16.7 or 20%, respectively (P < 0.05). NDGA alone (100 and 200 p.p.m.) slightly decreased the tumor incidence to 52.4 and 37%, respectively, although the difference was not statistically significant. DFMO alone did not show significant effects on tumor incidence. Inhibition of tumor formation by sulindac was correlated with lowered levels of PGE2. In conclusion, sulindac exerted its chemopreventive effect against the formation of EAC in the rat EGDA model possibly through its inhibition of Cox.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Animals; Arachidonic Acid; Body Weight; Cyclooxygenase 2; Dinoprostone; Eflornithine; Esophageal Neoplasms; Esophagus; Gas Chromatography-Mass Spectrometry; Hydroxyeicosatetraenoic Acids; Immunoenzyme Techniques; In Situ Hybridization; Inflammation; Isoenzymes; Leukotriene B4; Male; Masoprocol; Mass Spectrometry; Neoplasms; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Sprague-Dawley; Sulindac; Time Factors

In previous studies it had been shown that leukotriene-B4 [LTB4] concentrations in the exhaled breath mirror the inflammatory activity of the airways if the respiratory tract has been exposed to occupational hazards. In diving the respiratory tract is exposed to cold and dry air and the nasopharynx, as the site of breathing-gas warming and humidification, is bypassed. The aim of the present study was to obtain LTB4-concentrations in the exhaled breath and spirometric data of 17 healthy subjects before and after thirty minutes of technically dried air breathing at normobar ambient pressure. The exhaled breath was collected non-invasively, via a permanently cooled expiration tube. The condensate was measured by a standard enzyme immunoassay for LTB4. Lung function values (FVC, FEV1, MEF 25, MEF 50) were simultaneously obtained by spirometry. The measured pre- and post-exposure LTB4- concentrations as well as the lung function values were in the normal range. The present data gave no evidence for any inflammatory activity in the subjects' airways after thirty minutes breathing technically dried air.

Topics: Air; Breath Tests; Diving; Enzyme-Linked Immunosorbent Assay; Humans; Humidity; Inflammation; Leukotriene B4; Lung Diseases, Obstructive; Male; Occupational Diseases; Reference Values; Respiratory Function Tests; Spirometry

Topics: Animals; Arteriosclerosis; Cell Adhesion Molecules; Chemokine CCL2; Chemotaxis, Leukocyte; Inflammation; Leukocytes; Leukotriene Antagonists; Leukotriene B4; Macrophage-1 Antigen; Mice; Monocytes; Receptors, Leukotriene B4

From the galls of Pistacia terebinthus we obtained an extract that proved to be effective against chronic and acute inflammation. Now we report on the isolation and identification of three triterpenes: two tirucallane-type lanostanoids and one oleanane, which we have identified as masticadienonic acid (1), masticadienolic acid (2), and morolic acid (3), respectively. All of them showed effectiveness on the mouse ear inflammation induced by repeated applications of 12-O-tetradecanoylphorbol 13-acetate and on the phospholipase A2-induced foot paw edema. The pharmacological activity of the compounds was ratified by a histological study of the ear samples. In addition, they inhibited leukotriene B4 production in rat polymorphonuclear leukocytes stimulated with calcium ionophore A 23187.

Topics: Animals; Anti-Inflammatory Agents; Calcimycin; Cyproheptadine; Dexamethasone; Dose-Response Relationship, Drug; Hindlimb; Inflammation; Ionophores; Leukotriene B4; Magnetic Resonance Spectroscopy; Mice; Neutrophils; Phospholipases A; Phospholipases A2; Pistacia; Plant Extracts; Tetradecanoylphorbol Acetate; Triterpenes

Chronic inflammation of the oral epithelium of bacterial origin is associated with elevated leukotriene B(4) (LTB(4)) levels. We investigated leukotriene A(4) (LTA(4))-hydrolase expression and LTB(4) levels in oral epithelium in relation to the clinical disease manifestation and immunohistopathology and LTA(4)-hydrolase expression in cultured oral keratinocytes. In 11 patients, three different types of biopsy specimens of the oral mucosa tissues were examined. Each sample was divided, and one-half was analysed using immunohistochemistry with antibodies to LTA(4)-hydrolase, CD1a, CD3, CD19, macrophages/monocytes and granulocytes. The other half of the sample was homogenised and analysed using reverse-phase high-performance liquid chromatography to determine LTB(4) levels. We found strong LTA(4)-hydrolase expression in basal cells of the oral epithelium from tissue samples that appeared clinically healthy; however, histologically a mild chronic inflammation was observed. In contrast, patients with symptoms of an inflammation of the oral mucosa showed only weak LTA(4)-hydrolase staining of the epithelial cell layers, but strong immunoreactivity in endothelial and invading inflammatory cells. LTB(4) levels were elevated in inflamed tissues compared with non-inflamed controls. Most significantly, there was a strong association between the immunohistochemical detection of the enzyme, LTB(4) levels, cellular infiltration and the clinical disease manifestations. In vitro experiments indicated that LTA(4)-hydrolase expression may be induced by bacterial contamination. This study suggests that LTA(4)-hydrolase expression and elevated LTB(4) levels in oral mucosal epithelium are integral parts of the induction and progression of chronic inflammatory reactions. Epithelial cells may participate in early stages of inflammation as a source of LTB(4).

Topics: Adult; Aged; Bacterial Infections; Chromatography, High Pressure Liquid; Chronic Disease; Epoxide Hydrolases; Humans; Immunohistochemistry; Inflammation; Leukotriene B4; Middle Aged; Mouth Mucosa

Clinical and experimental findings had indicated that cigarette smoke exposure, and cyclooxygenase-2, are strongly associated with inflammatory bowel disease. The present study aimed to evaluate the role of cyclooxygenase-2 in the pathogenesis of experimental inflammatory bowel disease as well as in the adverse action of cigarette-smoke exposure. Rats were pretreated with different cyclooxygenase-2 inhibitors (indomethacin, nimesulide, or SC-236 (4-[5-(4-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide)) along with cigarette-smoke exposure before 2,4,6-trinitrobenzenesulfonic acid-enema. Results indicated that pretreatment with cyclooxygenase-2 inhibitors not only protected against 2,4,6-trinitrobenzenesulfonic acid-induced inflammatory bowel disease, but also attenuated the potentiating effect of cigarette-smoke exposure on colonic damage. Furthermore, the colonic cyclooxygenase-2 protein and mRNA expression was markedly induced by 2,4,6-trinitrobenzenesulfonic acid-enema, and it was potentiated further by cigarette-smoke exposure, while the cyclooxygenase-1 expression was not changed. The present study suggests that the highly induced cyclooxygenase-2 expression not only plays a pathogenic role in 2,4,6-trinitrobenzenesulfonic acid-induced inflammatory bowel disease, but also contributes to the adverse action of cigarette-smoke exposure on this disorder.

Topics: Animals; Blotting, Western; Colitis; Colon; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Gene Expression Regulation, Enzymologic; Indomethacin; Inflammation; Inflammatory Bowel Diseases; Isoenzymes; Leukotriene B4; Male; Membrane Proteins; Peroxidase; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sulfonamides; Tobacco Smoke Pollution; Trinitrobenzenesulfonic Acid

Leukotrienes (LTs) are considered important for antibacterial defense in the lung. Multidrug resistance protein 1 (mrp1) is a transmembrane protein responsible for the cellular extrusion of LTC(4). To determine the role of mrp1 in host defense against pneumonia, mrp1(-/-) and wild-type mice were intranasally inoculated with Streptococcus pneumoniae. mrp1(-/-) mice displayed a diminished outgrowth of pneumococci in lungs and a strongly reduced mortality. These findings were related to an effect of mrp1 on LT metabolism, because survival was similar in mrp1(-/-) and wild-type mice treated with the 5-lipoxygenase-activating protein inhibitor MK-886. Although LTC(4) levels remained low in the bronchoalveolar lavage fluid of mrp1(-/-) mice, LTB(4) concentrations were higher than in wild-type mice. These elevated LTB(4) concentrations were important for the relative protection of mrp1(-/-) mice, because the LTB(4) antagonist LTB(4)-dimethyl amide abolished their survival advantage. In vitro experiments suggested that the intracellullar accumulation of LTC(4) in mrp1(-/-) mice results in product inhibition of LTC(4)-synthase, diminishing substrate competition between LTA(4)-hydrolase (which yields LTB(4)) and LTC(4)-synthase for the available LTA(4). We conclude that mrp1(-/-) mice are resistant against pneumococcal pneumonia by a mechanism that involves increased release of LTB(4). These results identify mrp1 as a novel target for adjunctive therapy in pneumonia.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Female; Genetic Predisposition to Disease; Immunity, Innate; Indoles; Inflammation; Injections, Intraperitoneal; Intracellular Fluid; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Mice; Mice, Inbred Strains; Mice, Knockout; Pneumonia, Pneumococcal; Streptococcus pneumoniae; Up-Regulation

The studies were designed to investigate the differences in the intestinal inflammatory response following abdominopelvic or total-body irradiation in a ferret model.. Ferrets were exposed either to total-body or to abdominopelvic gamma-radiation (5 Gy) and various parameters of inflammation studied in the jejunum, ileum and colon 2 and 7 days later.. Abdominopelvic and, to a greater extent, total-body irradiation caused weight loss by 7 days. White blood cell counts were reduced in both groups, but more so following total-body irradiation. Myeloperoxidase activity was significantly increased in the ileum 2 days after abdominopelvic irradiation, but it was reduced after total-body irradiation. Total-body irradiation increased tissue prostaglandin E2 levels in all regions at 2 days and decreased jejunal leukotriene B4 levels in the jejunum at both time points. Ileal prostaglandin E2 levels were increased 2 days after abdominopelvic irradiation. Expression of inducible nitric oxide synthase was not altered by either irradiation protocol.. The data show that there are regional differences in the intestinal response to irradiation, depending on whether it was delivered to the whole body or locally to the abdominopelvic region. In particular, the ileum exhibited an acute increase in myeloperoxidase activity following abdominopelvic but not total-body irradiation.

Topics: Animals; Behavior, Animal; Colon; Dinoprostone; Ferrets; Ileum; Inflammation; Intestinal Mucosa; Intestines; Jejunum; Leukocyte Count; Leukotriene B4; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Peroxidase; Radiation Injuries, Experimental

We have investigated the mechanisms of action of aethiopinone, an anti-inflammatory compound from Salvia aethiopis L. roots.. Human neutrophils from healthy volunteers and murine peritoneal macrophages. Swiss mice were randomly divided into groups of six animals.. Test compounds were applied topically in the mouse ear oedema test. In the air pouch, mice received aethiopinone (0.001-0.5 pmol/pouch or 12.5-50 mg/kg p.o.).. LTB4 production was assayed in human neutrophils and COX-2 and iNOS activities in murine macrophages. Air pouches were induced subcutaneously in mice and injected with zymosan on the day six. Mouse ear oedema was induced by arachidonic acid. Dunnett's t-test was employed for statistical analysis.. We have observed potent inhibitory effects on human neutrophil LTB4 production without effects on COX or NOS activities. Aethiopinone is an in vitro inhibitor of 5-LO from human neutrophils (IC50 = 0.11 microM). In addition, aethiopinone reduced leukocyte accumulation and showed in vivo inhibitory activity on this enzyme.. Our results indicate that inhibition of 5-LO could participate in the anti-inflammatory properties of this natural product.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Cyclooxygenase 1; Cyclooxygenase 2; Dinoprostone; Ear; Edema; Humans; Inflammation; Isoenzymes; Leukotriene B4; Lipoxygenase Inhibitors; Macrophages, Peritoneal; Membrane Proteins; Mice; Naphthoquinones; Neutrophils; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Phospholipases A; Prostaglandin-Endoperoxide Synthases

Despite advances in understanding the pathophysiology of asthma, morbidity and mortality in pediatrics continue to rise. Little is known about the initiation and chronicity of inflammation resulting in asthma in this young population. We evaluated 20 "wheezing" children (WC) (median age 14.9 mo) with a minimum of two episodes of wheezing or prolonged wheezing > or = 2 mo in a 6-mo period with bronchoscopy and bronchoalveolar lavage (BAL). Comparisons were made with six normal controls (NC) (median age 23.3 mo) undergoing general anesthesia for elective surgery. BAL fluid cell counts and differentials were determined. The eicosanoids, leukotriene (LT) B(4), LTE(4), prostaglandin (PG)E(2), and 15-hydroxyeicosatetraenoic acid (HETE) and the mast cell mediators, beta-tryptase and PGD(2), were evaluated by enzyme immunoassay (EIA). WC had significant elevations in total BAL cells/ml (p = 0.01), as well as, lymphocytes (LYMPH, p = 0.007), macrophages/monocytes (M&M, p = 0.02), polymorphonuclear cells (PMN, p = 0.02), epithelial cells (EPI, p = 0.03), and eosinophils (EOS, p = 0.04) compared with NC. Levels of PGE(2) (p = 0.0005), 15-HETE (p = 0.002), LTE(4) (p = 0.04), and LTB(4) (p = 0.05) were also increased in WC compared with NC, whereas PGD(2) and beta-tryptase were not. This study confirms that inflammation is present in the airways of very young WC and may differ from patterns seen in adults with asthma.

Topics: Age Factors; Asthma; Bronchoalveolar Lavage Fluid; Bronchoscopy; Case-Control Studies; Chronic Disease; Dinoprostone; Disease Progression; Female; Humans; Hydroxyeicosatetraenoic Acids; Infant; Inflammation; Inflammation Mediators; Leukocyte Count; Leukotriene B4; Male; Prostaglandin D2; Respiratory Sounds; Risk Factors; Serine Endopeptidases; Tryptases

Cytosolic phospholipase A2 (cPLA2) catalyzes the selective release of arachidonic acid from the sn-2 position of phospholipids and is believed to play a key cellular role in the generation of arachidonic acid. BMS-229724 (4-[4-[2-[2-[bis(4-chlorophenyl)methoxy]ethyl-sulfonyl]ethoxy]phenyl]-1,1,1-trifluoro-2-butanone) was found to be a selective inhibitor of cPLA2 (IC50 = 2.8 microM) in that it did not inhibit secreted phospholipase A2 in vitro, nor phospholipase C and phospholipase D in cells. The compound was active in inhibiting arachidonate and eicosanoid production in U937 cells, neutrophils, platelets, monocytes, and mast cells. With a synthetic covesicle substrate system, the dose-dependent inhibition could be defined by kinetic equations describing competitive inhibition at the lipid/water interface. The apparent equilibrium dissociation constant for the inhibitor bound to the enzyme at the interface (K(I)*(app)) was determined to be 1. 10(-5) mol% versus an apparent dissociation constant for the arachidonate-containing phospholipid of 0.35 mol%. The unit of concentration in the interface is mole fraction (or mol%), which is related to the surface concentration of substrate, rather than bulk concentration that has units of molarity. Thus, BMS-229724 represents a novel inhibitor of cPLA2, which partitions into the phospholipid bilayer and competes with phospholipid substrate for the active site. This potent inhibition of the enzyme translated into anti-inflammatory activity when applied topically (5%, w/v) to a phorbol ester-induced chronic inflammation model in mouse ears, inhibiting edema and neutrophil infiltration, as well as prostaglandin and leukotriene levels in the skin. In hairless guinea pigs, BMS-229724 was active orally (10 mg/kg) in a UVB-induced skin erythema model in hairless guinea pigs.

Topics: Administration, Oral; Administration, Topical; Animals; Anti-Inflammatory Agents; Carcinogens; Chlorobenzenes; Dinoprostone; Dose-Response Relationship, Drug; Erythema; Female; Guinea Pigs; Humans; Inflammation; Leukotriene B4; Male; Mice; Neutrophils; Phorbol Esters; Phospholipases A; Phospholipases A2; Phospholipids; Platelet Activating Factor; Rats; Rats, Sprague-Dawley; Skin; Sulfones

Chemical examination of the MeOH extract of the root of Taraxacum officinale, which exhibited inhibitory activity on the formation of leukotriene B4 from activated human neutrophils, has resulted in the isolation of 14-O-beta-D-glucosyl-11,13-dihydro-taraxinic acid (1) and 14-O-beta-D-glucosyl-taraxinic acid (2). The absolute stereostructure of 1 has been established by X-ray chrystallographic examination.

Topics: Anti-HIV Agents; Asteraceae; Calcimycin; Cells, Cultured; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Crystallography, X-Ray; Dose-Response Relationship, Drug; Glucosides; HeLa Cells; HIV-1; Humans; Inflammation; Japan; Leukotriene B4; Molecular Conformation; Molecular Structure; Neutrophils; Nuclear Magnetic Resonance, Biomolecular; Plant Extracts; Plant Roots; Plants, Medicinal; Sesquiterpenes; Stereoisomerism; Structure-Activity Relationship

The alkaloid isaindigotone (1a) and seven derivatives have been synthesized to study their influence on several leukocyte functions and the generation of inflammatory mediators. Isaindigotone (1a) was found to be a scavenger of superoxide generated either by the hypoxanthine/xanthine oxidase system or stimulated human neutrophils. Isaindigotone (1a) and its acetylated derivative (1b) also inhibited 5-lipoxygenase activity and leukotriene B(4) production in these cells, whereas none of the compounds affected degranulation. In RAW 264.7 macrophages stimulated with lipopolysaccharide, synthetic derivatives exerted higher inhibitory effects on prostaglandin E(2) (PGE(2)) and nitric oxide (NO) generation when compared with (1a). The presence of an acetoxyl group at C-4' favors the inhibition of NO and PGE(2) production, whereas the fluoro substituent at C-4' or the absence of substituents on the aromatic ring of the benzylidene unit improves the inhibition of PGE(2). Thus, this series of compounds can attenuate the production of mediators relevant to the inflammatory response.

Topics: Alkaloids; Animals; Brassicaceae; Cells, Cultured; Chromatography, Thin Layer; Dinoprostone; Free Radical Scavengers; Humans; Inflammation; Inflammation Mediators; Inhibitory Concentration 50; Leukocytes; Leukotriene B4; Lipopolysaccharides; Lipoxygenase Inhibitors; Macrophages; Magnetic Resonance Spectroscopy; Mice; Molecular Structure; Neutrophils; Nitric Oxide Synthase; Plants, Medicinal; Quinazolines; Structure-Activity Relationship; Xanthine Oxidase

We have studied the effects of some hexahydroimidazo[1,2-c]pyrimidine derivatives (HIPs) on leucocyte functions in-vitro and we have assayed the anti-inflammatory activity of these compounds in two models of inflammation. All HIPs inhibited the human neutrophil degranulation process and superoxide generation at concentrations in the microM range. In mouse peritoneal macrophages stimulated with lipopolysaccharide, HIP-4 and HIP-5 inhibited nitrite production without affecting prostaglandin E2 (PGE2) accumulation. HIP-4 was also active in the zymosan-injected mouse air pouch model (at 100 nmol/pouch), with significant reductions in leucocyte migration and PGE2 and leukotriene B4 levels in the air pouch exudate. To confirm the anti-inflammatory effects of this compound, we tested HIP-4 orally (10-40 mg kg(-1)) on carrageenan mouse-paw oedema where it exerted a dose-dependent inhibition of paw swelling with significant reductions of myeloperoxidase and elastase activity and PGE2 levels in paw homogenates. This study demonstrates that some HIPs inhibit leucocyte functions and one of these derivatives (HIP-4) shows anti-inflammatory activity when administered by the oral route, which can be related to inhibition of leucocyte migration.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Dinoprostone; Edema; Female; Humans; Imidazoles; In Vitro Techniques; Inflammation; Leukocytes; Leukotriene B4; Macrophages; Macrophages, Peritoneal; Mice; Neutrophils; Nitrites; Pancreatic Elastase; Peroxidase; Pyrimidines; Superoxides; Zymosan

The present study was designed to examine the anti-inflammatory activity of the sesquiterpenoids ilicic acid and inuviscolide, isolated from Inula viscosa, on cell degranulation, leukotriene biosynthesis, neurogenic drive and glucocorticoid-like interactions. Swiss female mice were used to measure the ear oedema induced by phorbol esters or ethyl phenylpropiolate (EPP), and the paw oedema induced by phospholipase A(2) (PLA(2)) or serotonin. Drug treatment consisted of one topically-applied dose in the ear models and a subcutaneous or intraperitoneal injection in the paw models. Quantitative analysis of leukotriene B(4) (LTB(4)) formation was performed on rat peritoneal neutrophils by high performance liquid chromatography (HPLC). The lactone inuviscolide reduced the PLA(2)-induced oedema (ID(50): 98 micromol/kg). The effect on serotonin-induced oedema was not changed by modifiers of the glucocorticoid response. Ilicic acid showed minor in vivo effects, but was slightly more potent than inuviscolide on the 12-O-tetradecanoylphorbol 13-acetate (TPA) acute oedema test (ID(50): 0.650 micromol per ear). Inuviscolide reduced LTB(4) generation in intact cells, with an IC(50) value of 94 microM. On the basis of the reported results, inuviscolide is the main anti-inflammatory sesquiterpenoid from Inula viscosa, and may act by interfering with leukotriene synthesis and PLA(2)-induced mastocyte release of inflammatory mediators.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Degranulation; Dose-Response Relationship, Drug; Drug Interactions; Female; Glucocorticoids; Inflammation; Inhibitory Concentration 50; Inula; Leukotriene B4; Mice; Molecular Structure; Phytotherapy; Plant Preparations; Sesquiterpenes; Structure-Activity Relationship

1. We investigated the mediators responsible for neutrophil migration induced by ovalbumin (OVA) in immunized mice and the mechanisms involved in their release. 2. OVA administration promoted dose- and time-dependent neutrophil migration in immunized, but not in non-immunized mice, which was mediated by leukotriene B(4) (LTB(4)) and tumour necrosis factor (TNF)alpha, since it was inhibited by LTB(4) synthesis inhibitor (MK 886) or by LTB(4) receptor antagonist (CP 105,696), by dexamethasone and by antiserum to TNFalpha (82, 85, 63 and 87%, respectively). Confirming TNFalpha involvement, OVA challenge in immunized p55 TNF receptor deficient mice (p55(-/-)) did not promote neutrophil migration (control: 2.90 +/- 0.68; p55(-/-): 0.92+/-0.23 x 10(6) neutrophils cavity(-1)). 3. OVA-stimulated peritoneal cells from immunized mice released a neutrophil chemotactic factor which mimicked, in naive mice, neutrophil migration induced by OVA. 4. Supernatant chemotactic activity is due to TNFalpha and LTB(4), since its release was inhibited by MK 886 (93%) and dexamethasone (90%), and significant amounts of these mediators were detected. 5. TNFalpha and LTB(4) released by OVA challenge seem to act through a sequential mechanism, since MK 886 inhibited (88%) neutrophil migration induced by TNFalpha. Moreover, peritoneal cells stimulated with TNFalpha released LTB(4). 6. CD(4)(+) T cells are responsible for TNFalpha release, because the depletion of this subset prevented the release of TNFalpha (control: 400 +/- 25; immunized: 670 +/- 40; CD(4)(+) depleted: 435 +/- 18 pg ml(-1)). 7. In conclusion, neutrophil migration induced by OVA depends on TNFalpha released by CD(4)(+) cells, which acts through an LTB(4)-dependent mechanism.

Topics: Animals; Anti-Inflammatory Agents; Cell Survival; Cells, Cultured; Chemotaxis, Leukocyte; Dose-Response Relationship, Drug; Freund's Adjuvant; Inflammation; Leukotriene B4; Lymphocyte Subsets; Macrophages, Peritoneal; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Mutant Strains; Neutrophils; Ovalbumin; Time Factors; Tumor Necrosis Factor-alpha

Topics: Acne Vulgaris; Anti-Inflammatory Agents; Humans; Inflammation; Interleukin-1; Leukotriene B4; Propionibacterium acnes; Receptors, Cytoplasmic and Nuclear; Sebaceous Glands; Transcription Factors

One of the best known bioactive triterpenoids is oleanolic acid, a widespread 3-hydroxy-17-carboxy oleanane-type compound. In order to determine whether further oxidation of carbon 3 affects anti-inflammatory activity in mice, different tests were carried out on oleanolic acid and its 3-oxo-analogue oleanonic acid, which was obtained from Pistacia terebinthus galls. The last one showed activity on the ear oedema induced by 12-deoxyphorbol-13-phenylacetate (DPP), the dermatitis induced by multiple applications of 12-O-tetradecanoyl-13-acetate (TPA) and the paw oedemas induced by bradykinin and phospholipase A2. The production of leukotriene B4 from rat peritoneal leukocytes was reduced by oleanonic acid with an IC50 of 17 microM. Negligible differences were observed in the response of both triterpenes to DPP, bradykinin, and phospholipase A2, while oleanonic acid was more active on the dermatitis by TPA and on the in vitro leukotriene formation. In conclusion, the presence of a ketone at C-3 implies an increase in the inhibitory effects on models related to 5-lipoxygenase activity and on associated in vivo inflammatory processes.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Blood Platelets; Cyclooxygenase Inhibitors; Drug Screening Assays, Antitumor; Ear, External; Edema; Female; Foot; Humans; Hypersensitivity, Delayed; In Vitro Techniques; Inflammation; Leukotriene B4; Leukotrienes; Mice; Neutrophils; Oleanolic Acid; Oxidation-Reduction; Peroxidase; Pistacia; Rats; Structure-Activity Relationship; Tetrazolium Salts; Thiazoles; Triterpenes

Capsaicin, a pungent ingredient of hot peppers, causes excitation of small sensory neurons, and thereby produces severe pain. A nonselective cation channel activated by capsaicin has been identified in sensory neurons and a cDNA encoding the channel has been cloned recently. However, an endogenous activator of the receptor has not yet been found. In this study, we show that several products of lipoxygenases directly activate the capsaicin-activated channel in isolated membrane patches of sensory neurons. Among them, 12- and 15-(S)-hydroperoxyeicosatetraenoic acids, 5- and 15-(S)-hydroxyeicosatetraenoic acids, and leukotriene B(4) possessed the highest potency. The eicosanoids also activated the cloned capsaicin receptor (VR1) expressed in HEK cells. Prostaglandins and unsaturated fatty acids failed to activate the channel. These results suggest a novel signaling mechanism underlying the pain sensory transduction.

Topics: Animals; Capsaicin; Cell Line; Cells, Cultured; Dinoprostone; Eicosanoids; Ganglia, Spinal; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Ion Channel Gating; Leukotriene B4; Leukotrienes; Ligands; Lipid Peroxides; Lipoxygenase; Molecular Structure; Neurons, Afferent; Prostaglandin D2; Prostaglandin H2; Prostaglandins H; Rats; Receptors, Drug; Structure-Activity Relationship

The effects of ozone (O3) on airway epithelia, inflammation, and expression of inflammatory stimuli were investigated to delineate the mechanisms of inflammatory reactions relevant to lung injury. Because the airway responses to O3 develop gradually, this investigation included a time-sequence analysis. Rats exposed for 3 h to 1 ppm O3 were studied at 4-h intervals up to 20 h postexposure. Bronchoalveolar lavage fluid (BAL) was analyzed for albumin as an indicator of increased permeability, polymorphonuclear leukocytes (PMNs) to assess the inflammatory status, macrophage inflammatory protein-2 (MIP-2, an inflammatory chemokine), and cell adhesion molecules for their role in inflammation and PMN functions. The time-related increase in albumin was matched by a similar significant increase for PMNs, MIP-2, and intercellular adhesion molecule-1 (ICAM-1). However, no marked change occurred for beta-2 integrin (CD-18) and leukotriene B4 (LTB4). The results establish a temporal correlation of epithelial permeability with changes in inflammatory activity and stimuli responsible for PMN recruitment in the lung. The observations of elevated MIP-2 and ICAM-1 levels are consistent with their role in injury and inflammation. An early expression of MIP-2 mRNA in BAL cells, that is, immediately post O3 exposure, and the peak increase in BAL MIP-2 levels 4 h later support the chemotactic role of MIP-2 in PMN recruitment at 4- and 12-h time points. The rapid drop in MIP-2 and ICAM-1 levels appears to signal the termination of inflammatory cell recruitment, which is accompanied by an onset of recovery.

Topics: Air Pollution; Albumins; Animals; Blotting, Western; Bronchoalveolar Lavage Fluid; CD18 Antigens; DNA Primers; Environmental Exposure; Enzyme-Linked Immunosorbent Assay; Inflammation; Intercellular Adhesion Molecule-1; Leukotriene B4; Lung; Lung Diseases; Macrophage Inflammatory Proteins; Male; Neutrophils; Oxidants, Photochemical; Ozone; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Specific Pathogen-Free Organisms; Time Factors

We examined the in vivo actions of LY293111 sodium (2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy]pro poxy]phenoxy] benzoic acid sodium salt). Guinea pigs were used to evaluate the effect of this agent on (1) acute airway obstruction produced by intravenous leukotriene B4, (2) pulmonary granulocyte infiltration and delayed onset airway obstruction resulting from a 4-h leukotriene B4 inhalation and (3) lung inflammation after aerosol challenge with the divalent cationic ionophore A23187 (6S-[6alpha(2S*,3S*),8beta(R*),9beta,11alpha]-5- (methylamino)-2-[[3,9,11-trimethyl-8-[1-methyl-2-oxo-2-(1H-pyrrol-2-yl)e thyl]-1,7-dioxaspiro[5.5]undec-2-yl]methyl]-4-benzoxazole carboxylic acid). Airway obstruction was quantitated using pulmonary gas trapping measurements and lung inflammation was evaluated by bronchoalveolar lavage (BAL) and histology. LY293111 sodium produced a dose-related inhibition of acute leukotriene B4-induced airway obstruction when administered i.v. (ED50=14 microg/kg) or p.o. (ED50=0.4 mg/kg). In contrast, LY293111 sodium did not inhibit the pulmonary gas trapping caused by aerosols of histamine, leukotriene D4, or the thromboxane mimetic U46619 (15 [(S)-hydroxy11a,9a-(epoxymethano)prosta-5Z,13E-dienoic acid]). Oral LY293111 sodium inhibited leukotriene B4-induced bronchoalveolar lavage granulocyte infiltration and delayed onset airway obstruction at doses as low as 0.3 mg/kg. In A23187-challenged animals, pulmonary inflammation was markedly inhibited at 1 h, but not 2 h and 4 h post-exposure. We conclude that LY293 11 sodium is a selective leukotriene B4 receptor antagonist with potent pulmonary anti-inflammatory activity.

Topics: Airway Obstruction; Animals; Benzoates; Benzopyrans; Bronchoalveolar Lavage Fluid; Calcimycin; Chemotaxis, Leukocyte; Dinoprostone; Granulocytes; Guinea Pigs; Inflammation; Leukotriene Antagonists; Leukotriene B4; Lung; Male; Receptors, Leukotriene B4; Thromboxane B2

Topics: Amyloid beta-Peptides; Animals; Aorta; Cyclic GMP; Dipyridamole; Endothelin-1; In Vitro Techniques; Inflammation; Leukotriene B4; Microglia; Muscle, Smooth, Vascular; Nitroprusside; Peptide Fragments; Rats; Vasoconstriction

A ditriazine derivative (4,10-dichloropyrido[5,6:4,5]thieno[3,2-d':3, 2-d]-1,2,3-ditriazine (DTD)) inhibited neutrophil functions, including degranulation, superoxide generation, and leukotriene B(4) production, without any effect on 5-lipoxygenase activity. This compound reduced nitric oxide (NO) and prostaglandin E(2) production in mouse peritoneal macrophages stimulated with lipopolysaccharide, whereas no influence on the activity of inducible NO synthase, cyclo-oxygenase-2 or cyclo-oxygenase-1 was observed. DTD significantly reduced mouse paw oedema induced by carrageenan and also markedly reduced NO and prostaglandin E(2) levels in exudates from 24-h zymosan-stimulated mouse air pouch. Western blot analysis showed that DTD reduced the expression of inducible NO synthase and cyclo-oxygenase-2. Our results indicate that DTD exerts anti-inflammatory effects related to the inhibition of neutrophil functions and of NO and prostaglandin E(2) production, which could be due to a decreased expression of inducible NO synthase and cyclo-oxygenase-2.

Topics: Animals; Anti-Inflammatory Agents; Blood Platelets; Carrageenan; Cell-Free System; Cyclooxygenase 2; Dinoprostone; Dose-Response Relationship, Drug; Edema; Female; Hindlimb; Humans; Inflammation; Isoenzymes; Leukocytes; Leukotriene B4; Luminescent Measurements; Macrophages, Peritoneal; Membrane Proteins; Mice; Microsomes; Neutrophil Activation; Neutrophils; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitrites; Pancreatic Elastase; Phospholipases A; Prostaglandin-Endoperoxide Synthases; Thromboxane B2; Triazines; Zymosan

Inflammatory cells contribute to the acute and sub-acute sequelae of radiation therapy. Tepoxalin, an inhibitor of cyclooxygenase and 5-lipoxygenase that suppresses NF-kappaB activation, has potent anti-inflammatory activity.. To assess the effects of tepoxalin on radiation-induced inflammatory damage, and determine its mechanisms of action.. Leucocyte rolling, adhesion and emigration, and albumin leakage were determined by intra-vital microscopy in rat mesenteric venules. NF-kappaB activation was measured by electrophoretic mobility shift assays, and endothelial intercellular adhesion molecule-1 expression by the radiolabelled antibody technique. Groups of irradiated rats were treated with tepoxalin, N-acetyl-L-cysteine, zileuton (lipoxygenase inhibitor), or vehicle.. Irradiated animals had a marked increase in the number of rolling, adherent and emigrated leucocytes in mesenteric venules, and in microvascular permeability. Tepoxalin prevented leucocyte adhesion and the increase in permeability after radiation. Tepoxalin did not inhibit radiation-induced NF-kappaB activation or intercellular adhesion molecule-1 up-regulation, while N-acetyl-L-cysteine, which attenuated NF-kappaB activation, had no effect on leucocyte recruitment. In contrast, tepoxalin inhibited the increase in leukotriene B4 levels after radiation, and the anti-inflammatory effects of the drug were mimicked by zileuton.. Tepoxalin affords significant protection against radiation-induced inflammation and microvascular dysfunction in splanchnic organs through a mechanism dependent on leukotriene synthesis inhibition.

Topics: Abdomen; Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Adhesion; Digestive System; Inflammation; Leukocytes; Leukotriene B4; Male; Permeability; Pyrazoles; Radiotherapy; Rats; Rats, Sprague-Dawley

A method has been developed for the direct quantification of the CD11b integrin on granulocytes by flow cytometric analysis of whole blood specimens following either LTB(4) or lipopolysaccharide (LPS) stimulation. This method has utility in evaluating the pharmacodynamic action of either LTB(4) receptor antagonists or immune cell modulators in effecting CD11b integrin expression and granulocyte activation in human subjects administered such drugs. Previous studies using CD11b as a biomarker of granulocyte activation have faltered because of the difficulty in controlling the activation state of the granulocyte following removal of blood from subjects. The present study has made use of a newly validated method using either LTB(4) or LPS to stimulate CD11b expression on granulocytes and has been used, as one measure, in the evaluation of LPS activity when administered to normal human volunteers.

Topics: Acrylates; Adjuvants, Immunologic; Binding, Competitive; Flow Cytometry; Humans; Inflammation; Integrins; Leukotriene B4; Leukotriene D4; Lipopolysaccharides; Macrophage-1 Antigen; Male; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Pyridines; Receptors, Leukotriene B4

We previously demonstrated that captopril (CP) exhibited a high ability to inhibit enzymatically generated leukotrienes, particularly LTB(4), from stimulated intact human neutrophils. This finding together with the immunosuppressive effect of CP have proposed a possible antiinflammatory activity for the drug. Thus, the present study was conducted to investigate the effect of CP on immunologically mediated chronic inflammation; two models were chosen, namely, Freund's adjuvant arthritis and mixed-type hypersensitivity in rat. The effect of CP was assessed on the basis of physical parameter (paw edema) and biochemical markers in blood and inflammatory exudate. CP was given daily during the course of inflammation development. It was administered ip at three doses, viz. 1, 10, and 100 mg/kg. The results claimed that CP succeeded in suppressing edema evolution in hind paws of Freund's arthritic animals, during all phases of the disease. During the chronic phase of inflammation, in either model, CP reduced the elevated serum and exudate (local) LTB(4) and IL-6 levels. The effect on LTB(4) was more pronounced in the exudate and tended to be dose-related. The antiarthritic effect of CP was also accompanied by augmentation of serum level of protein thiols, with reduction or normalization of elevated systemic and/or local levels of lipid peroxide, superoxide dismutase, and glutathione. It could be concluded that long-term treatment with CP confers a good antiinflammatory activity against arthritis in rat, leading to improvement of the oxidative stress induced by the arthritic insult. The reparative effect of the drug could be mediated via reduction of LTB(4) and IL-6.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Experimental; Captopril; Edema; Exudates and Transudates; Freund's Adjuvant; Hindlimb; Hypersensitivity; Inflammation; Interleukin-6; Leukotriene B4; Male; Oxidative Stress; Peptidyl-Dipeptidase A; Rats; Rats, Wistar; Thiobarbituric Acid Reactive Substances

It has been suggested that multiple sublethal insults are commonly associated with the development of multiple organ failure (MOF). The gut is considered to be pivotal in the pathogenesis of MOF. This study investigated the effects of repeated ischemia-reperfusion of the rat small intestine.. Groups of rats underwent 30 min of superior mesenteric artery occlusion or sham operation followed by 24 h of reperfusion. They then received an additional 30 min of superior mesenteric artery occlusion and 2 h of reperfusion or sham operation. Small intestine was examined for mucosal injury, neutrophil infiltration, goblet cell number, and generation of the eicosanoids, prostaglandin E2, and leukotriene B4. Activation of neutrophils was assessed in systemic venous blood.. Animals subjected to two insults of ischemia-reperfusion demonstrated significantly less mucosal injury than animals undergoing one episode of ischemia and 2 h of reperfusion, despite increased neutrophil infiltration, leukotriene B4, and activated systemic neutrophils. Goblet cell number was elevated in animals 24 h after the first ischemia-reperfusion insult and remained enhanced after the second episode of ischemia-reperfusion.. The initial episode of ischemia-reperfusion caused an adaptive response associated with cytoarchitectural preservation following the subsequent insult. Increased mucus production was associated with mucosal protection. Nevertheless, repeated ischemia-reperfusion potentiated the local inflammatory response and the systemic activation of neutrophils.

Topics: Animals; Dinoprostone; Disease Models, Animal; Inflammation; Intestinal Mucosa; Intestine, Small; Leukotriene B4; Male; Multiple Organ Failure; Neutrophil Activation; Rats; Rats, Sprague-Dawley; Recurrence; Reperfusion Injury

The marine product petrosaspongiolide M is a novel inhibitor of phospholipase A2 (PLA2), showing selectivity for secretory PLA2 versus cytosolic PLA2, with a potency on the human synovial enzyme (group II) similar to that of manoalide. This compound was more potent than manoalide on bee venom PLA2 (group III) and had no effect on group I enzymes (Naja naja and porcine pancreatic PLA2). Inhibition of PLA2 was also observed in vivo in the zymosan-injected rat air pouch, on the secretory enzyme accumulated in the pouch exudate. Petrosaspongiolide M decreased carrageenan paw edema in mice after the oral administration of 5, 10, or 20 mg/kg. This marine metabolite (0.01-1.0 micromol/pouch) induced a dose-dependent reduction in the levels of prostaglandin (PG)E2, leukotriene B4, and tumor necrosis factor-alpha in the mouse air pouch injected with zymosan 4 h after the stimulus. It also had a weaker effect on cell migration. The inflammatory response of adjuvant arthritis was reduced by petrosaspongiolide M, which also inhibited leukotriene B4 levels in serum and PGE2 levels in paw homogenates. In contrast with indomethacin, this marine compound did not reduce PGE2 levels in stomach homogenates. Petrosaspongiolide M is a new inhibitor of secretory PLA2 in vitro and in vivo, with anti-inflammatory properties in acute and chronic inflammation.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Experimental; Cell Survival; Dinoprostone; Edema; Enzyme Inhibitors; Exudates and Transudates; Humans; In Vitro Techniques; Inflammation; Leukocytes; Leukotriene B4; Male; Mice; Oleanolic Acid; Phospholipases A; Phospholipases A2; Porifera; Rats; Rats, Inbred Lew; Rats, Wistar; Tumor Necrosis Factor-alpha; U937 Cells

The contribution of platelets to arachidonic acid transcellular metabolism may represent an important pathway of leukotriene (LT) production. The aim of this study was to investigate the role of platelets on LT production in an acute inflammatory model in the rabbit. Preliminary experiments showed that rabbit whole blood (5 ml) stimulated in vitro with the calcium ionophore A23187 produced LTB4 (52.7+/-13.9 ng) and the mixed 5,12-DiHETE (7.25+/-0.75 ng). In A23187-stimulated thrombocytopenic blood, LTB4 was significantly reduced to 19.5+/-8.6 ng and 5,12-DiHETE was undetectable. Peptido-LTs were undetectable in both conditions. In experiments using washed cells, addition of thrombin-activated platelets to fMLP-activated PMN resulted in the appearance of 5,12-DiHETE and in more than twofold increase of LTB4 synthesis. When 3H-arachidonic acid-labelled platelets were mixed with unlabelled PMN and challenged with fMLP and thrombin, radioactive LTB4 and 5,12-DiHETE were produced, indicating that platelet-derived arachidonic acid was utilized by PMN 5-lipoxygenase. Intravenous infusion of fMLP (2.5 nmol/kg/min) in the rabbit induced marked granulocytopenia, thrombocytopenia and increased TxB2 plasma concentrations within 3 min. Electron microscopy of lungs showed morphologically activated and aggregated platelets occluding the capillary lumen. Activation and recruitment of circulating cells was accompanied by the production of LTB4 (peak levels at 1 min: 30.0+/-9.5 ng/ml) and LTE4 (peak levels at 10 minutes: 77.8+/-11.6 ng/ml). The areas under the blood concentration-time curve (AUC, ng min/ml) corresponded to 812+/-182 and 3692+/-658 for LTB4 and LTE4, respectively. In immunologically thrombocytopenic rabbits, the AUC for LTB4 (86.0+/-23.0) and LTE4 (1165+/-542) were both significantly different from controls while in rabbits treated with an anti-leukocyte antiserum, both LTB4 and LTE4 were similar to controls. This experimental model provides in vivo evidence that platelets, involved in an acute inflammatory event contribute to the transcellular production of LTs.

Topics: Animals; Arachidonic Acid; Blood Platelets; Calcimycin; Inflammation; Ionophores; Leukotriene B4; Leukotrienes; Male; Platelet Activation; Rabbits

The effect of single or combined administration of indomethacin and misoprostol on the exudate leukocyte count and thromboxane B2, a stable metabolite of thromboxane A2, and on the leukotriene B4 level, as cyclooxygenase and lipoxygenase metabolites of arachidonic acid, was investigated in acute carrageenan-induced air pouch inflammation in rats. Administration of indomethacin (0.25 to 4 mg/kg) 1 h before carrageenan given by the orogastric route reduced the exudate leukocyte count and thromboxane B2 level whereas it increased the exudate leukotriene B4 level dose dependently. Administration of misoprostol, a synthetic prostaglandin E1 analogue, (12.5 to 100 microg/kg) twice daily for two days before carrageenan given by the orogastric route increased the exudate leukocyte count. Combined misoprostol and indomethacin did not change the effect of indomethacin alone on exudate leukocyte count. Misoprostol, when used alone, decreased exudate thromboxane B2 level significantly. However, misoprostol did not change the exudate leukotriene B4 level, while its combination with indomethacin prevented the indomethacin-induced increase in exudate leukotriene B4 level. In conclusion, although misoprostol can be combined with non-steroidal anti-inflammatory drugs in many chronic inflammatory situations, our results indicate that misoprostol may also be combined with indomethacin in acute inflammation without producing any change on the antiinflammatory efficacy of indomethacin in rats.

Topics: Analysis of Variance; Animals; Anti-Ulcer Agents; Carrageenan; Cyclooxygenase Inhibitors; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Therapy, Combination; Excipients; Female; Immunoenzyme Techniques; Indomethacin; Inflammation; Leukocyte Count; Leukotriene B4; Misoprostol; Rats; Rats, Wistar; Thromboxane B2

To investigate the role of eicosanoid generation and neutrophilic infiltration in the protective effects of U74389F against ischemia/reperfusion injury in the small intestines of rats.. Prospective, randomized, controlled study.. University research laboratory.. Adult, male Sprague-Dawley rats weighing between 200 and 300 g.. Groups (5-8) of rats treated with U74389F or vehicle were subjected to a sham operation and 30 mins of ischemia by occlusion of the superior mesenteric artery or 30 mins of ischemia followed by 60 or 120 mins of reperfusion. U74389F (2.5 mg/kg i.v.) or vehicle (citrate buffer) were slowly injected 2 mins before ischemia.. Ischemia significantly (p < .05) increased mucosal injury (0 [normal] to 5) in both U74389F and untreated rats. In contrast, U74389F significantly (p < .05) attenuated the severity of injury after reperfusion. In vehicle-treated rats, ischemia/reperfusion significantly reduced villus height in both U74389F and untreated groups. However, the surface epithelial layer was intact in the U74389F but not in the vehicle-treated group. In addition, compared with the vehicle-treated group, U74389F significantly reduced neutrophil infiltration and prevented the increase in leukotriene B4 and prostaglandin E2 in response to ischemia and reperfusion.. This study demonstrates that the mechanism of U74389F against mesenteric ischemia/reperfusion includes a delay and reduction of neutrophilic infiltrate, an inhibition of leukotriene B4 production, and a facilitation of mucosal restitution.

Topics: Animals; Antioxidants; Dinoprostone; Disease Models, Animal; Drug Evaluation, Preclinical; Eicosanoids; Immunosuppressive Agents; Inflammation; Injections, Intravenous; Intestine, Small; Leukotriene B4; Male; Neutrophil Activation; Pregnatrienes; Prospective Studies; Random Allocation; Rats; Rats, Sprague-Dawley; Reperfusion Injury

Topics: Acute Disease; Animals; Blood Platelets; Disease Models, Animal; In Vitro Techniques; Inflammation; Kinetics; Leukocyte Count; Leukocytes, Mononuclear; Leukotriene B4; Leukotriene E4; Male; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Platelet Count; Rabbits

To investigate the characteristics of anterior chamber inflammatory reaction induced by intravitreal injection of endothelin-1 (ET-1).. The time course of changes in aqueous protein concentration (APC) after intravitreal injection of 10(-4), 10(-5), 10(-6) and 10(-7) M ET-1 into rabbit eyes was measured with a laser flare-cell meter. The influence of a topical diclofenac sodium (DFNa) pre- and post-treatment was assessed. Aqueous prostaglandin E2 and leukotriene B4 concentration was quantified using a radioimmunoassay technique.. Intravitreal injection of 10(-4) and 10(-5) M ET-1 significantly increased APC, while 10(-6) and 10(-7) M ET-1 did not induce anterior chamber inflammation. After 10(-5) M ET-1 injection, APC reached a maximum at 4 h post-treatment and returned to a normal level 48 h after injection. Eyes treated with 10(-4) M ET-1 displayed a bi-phasic time course, with peak values observed 4 to 8 h as well as 48 h after administration. Pre- and post-treatment with topical DFNa completely suppressed the APC increase in the 10(-5) M ET-1 preparation, and considerably inhibited it in the 10(-4) M ET-1 preparation. After ET-1 injection, aqueous prostaglandin E2 concentration increased significantly, followed by an increase in APC. There were no changes in leukotriene B4 concentration.. ET-1 induces anterior chamber inflammation via the cyclooxygenase pathway of the arachidonic acid cascade. The lipoxygenase pathway is not involved in this reaction.

Topics: Administration, Topical; Animals; Anterior Chamber; Aqueous Humor; Cyclooxygenase Inhibitors; Diclofenac; Dinoprostone; Endothelin-1; Eye Proteins; Female; Inflammation; Injections; Leukotriene B4; Male; Rabbits; Radioimmunoassay; Uveitis, Anterior; Vitreous Body

In the present study, we investigated the role of mast cells in a model of polyacrylamide gel (PAG)-induced inflammation in mice.. Balb/c mice and two strains of mast cell deficient mice (WBB6F1/J-W/Wv, WCB6F1/J-S1/S1d).. Various quantities of polyacrylamide gel (Bio-Gel P4) were injected subcutaneously in the backs of mice.. Five hours after the injection of PAG the animals were euthanized, the injection sites lavaged and levels of LTB4, PGE2, TNF alpha and cells were determined.. Subcutaneous injection of PAG caused a time-dependent response characterized by the accumulation of inflammatory cells peaking at 10 h and the formation of LTB4, PGE2 and TNF alpha, peaking at 5 h. PAG injection into W/Wv or SL/SLd mice (mice lacking mast cells) resulted in an attenuated response, i.e. LTB4 levels were reduced by 60% and minimal cell influx was seen. The lack of mast cells caused about a 30% reduction in the levels of TNF alpha found.. These data suggest that mast cells play a prominent role in the PMN influx, TNF alpha production and eicosanoid formation in the PAG-induced inflammatory response.

Topics: Acrylic Resins; Animals; Anti-Inflammatory Agents; Dinoprostone; Hydroxyurea; Inflammation; Leukocyte Count; Leukotriene B4; Lipoxygenase Inhibitors; Mast Cells; Mice; Mice, Inbred BALB C; Neutrophils; Peroxidase

Increased vascular endothelial cell (EC) permeability and neutrophilic leukocyte (PMN) diapedesis through paracellular gaps are cardinal features of acute inflammation. Activation of the EC contractile apparatus is necessary and sufficient to increase vascular permeability in specific models of EC barrier dysfunction. However, it is unknown whether EC contraction with subsequent paracellular gap formation is required for PMN transendothelial migration in response to chemotactic factors. To test this possibility, we assessed migration of human PMNs across confluent bovine pulmonary arterial EC monolayers. Transendothelial PMN migration in the absence of a chemotactic gradient was minimal, whereas abluminal addition of leukotriene B4 (LTB4; 5 microM) resulted in significantly increased PMN migration. Reductions in EC myosin light chain kinase (MLCK) activity by EC monolayer pretreatment with specific MLCK inhibitors (KT-5926 or ML-7) or by increases in cAMP-protein kinase A activity (cholera toxin) significantly reduced PMN transmigration (30-70% inhibition). In contrast, pretreatment with the myosin-associated phosphatase inhibitor calyculin resulted in the accumulation of phosphorylated myosin light chains, EC contraction, and significantly enhanced PMN migration. Finally, the interaction of PMNs with 32P-labeled EC monolayers was shown to directly increase EC myosin phosphorylation in a time-dependent fashion. Taken together, these results are consistent with the hypothesis that the phosphorylation status of EC myosin regulates PMN migration and further indicate that EC MLCK is activated by chemoattractant-stimulated PMNs. Neutrophil-dependent activation of the EC contractile apparatus with subsequent paracellular gap formation may be a key determinant of transendothelial PMN migration responses to chemotactic agents.

Topics: Alkaloids; Animals; Azepines; Capillary Permeability; Carbazoles; Cattle; Cell Adhesion; Cell Movement; Cells, Cultured; Chemotactic Factors; Cyclic AMP-Dependent Protein Kinases; Endothelium, Vascular; Enzyme Activation; Enzyme Inhibitors; Indoles; Inflammation; Leukotriene B4; Marine Toxins; Muscle, Smooth, Vascular; Myosin-Light-Chain Kinase; Naphthalenes; Neutrophils; Oxazoles; Phosphorylation; Pulmonary Artery

A series of prenyl hydroquinone derivatives synthesized as structural analogs of marine products were tested for their effects on inflammatory responses in vitro and in vivo. 2-Prenyl-1,4-hydroquinone (H1), 2-diprenyl-1,4-hydroquinone (H2), 2-triprenyl-1,4-hydroquinone (H3) and 2-tetraprenyl-1,4-hydroquinone (H4) scavenged reactive oxygen species and inhibited 5-lipoxygenase (5-LO) activity in human neutrophils. The inhibition of 5-LO activity was demonstrated in vivo in the mouse air pouch injected with zymosan and arachidonic acid-induced ear inflammation. The four compounds suppressed the production of tumour necrosis factor alpha (TNFalpha) in J774 cells stimulated with lipopolysaccharide (LPS) and also in vivo in the mouse air pouch injected with zymosan. In addition, all prenyl-hydroquinones inhibited the release of nitrite and PGE2 in LPS-stimulated J774 cells, without direct effects on cyclo-oxygenase-1 (COX-1), cyclo-oxygenase-2 (COX-2) or inducible nitric oxide synthase (iNOS) activities in several cell-free systems. The reduction in the length of the lateral chain in prenyl-hydroquinones (1-4 isoprene units) with respect to their marine analogs (7-8 isoprene units) has improved the anti-inflammatory activity of this class of compounds. Marine natural products may be a model to design new anti-inflammatory agents.

Topics: Animals; Anti-Inflammatory Agents; Arachidonic Acid; Cells, Cultured; Depression, Chemical; Dinoprostone; Edema; Humans; Hydroquinones; Inflammation; Leukotriene B4; Luminescent Measurements; Male; Mice; Nitrites; Tumor Necrosis Factor-alpha

The anti-inflammatory effects of the non-steroidal anti-inflammatory drugs phenylbutazone (PBZ) and flunixin meglumine (FM) and the relationship between the effects and drug concentration in vivo were studied using a subcutaneous tissue-cage model in sheep. Intracaveal injection of carrageenan induced prostaglandin (PG) E2 production in tissue-cage exudate (maximal concentration, 101 nM) with significant increases in white blood cell (WBC) numbers, skin temperature over the inflamed cage and exudate leukotriene B4 (LTB4) concentration (P < 0.05). Intravenous PBZ, 4.4 mg kg-1 produced mild inhibition of exudate PGE2 generation (10%), but greater inhibition of serum TXB2 (75.3%). The IC50 for TXB2 was 36.0 microM. Phenylbutazone did not alter effects on skin temperature, WBC numbers or exudate LTB4 concentrations. Intravenous FM, 1.1 mg kg-1, significantly inhibited carrageenan-induced exudate PGE2 formation (Emax, 100%, IC50, < 0.4 nM) and serum TXB2 generation (Emax, 100%, IC50, 17 nM) for up to 32 h. Flunixin meglumine significantly inhibited the rise in skin temperature but had a limited effect on exudate WBC. Phenylbutazone and FM have distinct effects on carrageenan-induced cyclooxygenase (COX-2) and platelet COX (COX-1). Flunixin meglumine was a more potent COX inhibitor than PBZ and was more selective for the inducible form of COX in vivo.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Clonixin; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Diffusion Chambers, Culture; Dinoprostone; Inflammation; Isoenzymes; Leukocyte Count; Leukotriene B4; Male; Phenylbutazone; Prostaglandin-Endoperoxide Synthases; Sheep; Skin Temperature; Thromboxane B2

Leukotriene B4 (LTB4), an arachidonic acid derivative, is a potent proinflammatory agent whose actions are terminated by catabolism via a microsomal omega-hydroxylation pathway. Although the liver serves as the principal site for LTB4 clearance from the systemic circulation, the attributes of hepatic LTB4 metabolism are ill defined in humans. Thus, we examined metabolism of LTB4 to its omega-hydroxylated metabolite 20-hydroxyleukotriene B4 (20-OH LTB4) by human liver microsomes and also purified the hepatic P450 enzyme underlying this reaction. Liver microsomes from 10 different subjects converted LTB4 to 20-OH LTB4 at similar rates (1.06 +/- 0.3 nmol/min/nmol P450; 0.25 +/- 0.1 nmol/min/mg protein). Analysis of the microsomal LTB4 20-hydroxylation reaction revealed kinetic parameters (apparent Km of 74.8 microM with a VMAX of 2.42 nmol/min/nmol P450) consistent with catalysis by a single P450 enzyme. Conventional chromatography combined with immunochemical screening with rat CYP4A1 antibodies was then used to isolate a P450 enzyme from human liver microsomes with a molecular weight of 57,000 and an NH2-terminal amino acid sequence 94% homologous (12Trp --> 12Gly) over the first 17 residues with the human CYP4F2 cDNA-derived sequence. Upon reconstitution with P450 reductase and phospholipid, CYP4F2 converted LTB4 to 20-OH LTB4 at a turnover rate of 392 pmol/min/nmol P450, whereas the other human liver P450s tested, including CYP4A11, exhibited neglible LTB4 omega-hydroxylase activity. Polyclonal antibodies to CYP4F2 were found to markedly inhibit (91.9 +/- 5%; n = 5) LTB4 20-hydroxylation by human liver microsomes. Microsomal 20-OH LTB4 formation was also inhibited 30% by arachidonic acid, a known CYP4F2 substrate, and 50% by prostaglandin A1 but was unaffected by lauric acid, palmitic acid, and PGF2alpha. Finally, a strong correlation (r = 0.86; P < 0.002; n = 10) was observed between CYP4F2 content and LTB4 20-hydroxylase activity in the human liver samples. Our results indicate that CYP4F2 is the principle LTB4 omega-hydroxylating enzyme expressed in human liver and, as such, may play an important role in regulating circulating as well as hepatic levels of this powerful proinflammatory eicosanoid.

Topics: Amino Acid Sequence; Cytochrome P-450 Enzyme System; Cytochrome P450 Family 4; Humans; Hydroxylation; Immunochemistry; Inflammation; Leukotriene B4; Microsomes, Liver; Mixed Function Oxygenases; Molecular Sequence Data

Cineole (eucalyptol) is the isolated active agent of eucalyptus oil. Traditionally, it is recommended for treating the symptoms of airway diseases exacerbated by infection. We have examined the inhibitory effect of 1.8-cineole on LPS-and IL1beta-stimulated mediator production by human monocytes in vitro. For the first time, we report on a dose-dependent and highly significant inhibition of production of tumor necrosis factor-alpha, interleukin-1beta, leukotriene B4 and thromboxane B2 by 1.8-cineole. In summary, this is the first report on a new mechanism of action of monoterpenes suggesting 1.8-cineole as a strong inhibitor of cytokines that might be suitable for longterm treatment of airway inflammation in bronchial asthma and other steroid-sensitive disorders.

Topics: Adult; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Asthma; Cyclohexanols; Cytokines; Eucalyptol; Female; Humans; In Vitro Techniques; Inflammation; Inflammation Mediators; Interleukin-1; Leukotriene B4; Lipopolysaccharides; Male; Menthol; Monocytes; Monoterpenes; Respiratory Tract Diseases; Terpenes; Thromboxane B2; Tumor Necrosis Factor-alpha

The objective of the present study was to assess the role of lipid mediators and adhesion molecule expression in exacerbation of ischemia-reperfusion-induced inflammatory response in diabetes. Leukocyte-endothelial cell interactions were studied in mesenteric venules by intravital microscopy. Endothelial expression of intercellular adhesion molecule (ICAM)-1 was measured by the double-radiolabeled monoclonal antibody technique, and beta2-integrin expression was measured by flow cytometry. Ischemia-reperfusion elicited significantly larger increases in leukocyte adhesion and emigration in diabetic rats that were prevented by a platelet-activating factor (PAF)-receptor antagonist or a leukotriene synthesis inhibitor. Leukotriene B4 (LTB4) superfusion induced similar leukocyte recruitment in diabetic and control rats, whereas PAF elicited larger increases in diabetic rats. CD11a, but not CD11b, expression was higher in leukocytes from diabetic animals. Endothelial ICAM-1 in mesentery and in intestine did not differ between diabetic and control rats. These results indicate that diabetes is associated with an enhanced response to ischemia-reperfusion that depends on both PAF and leukotrienes. An increased sensitivity to PAF, along with an increased CD11a expression, may account for the exaggerated inflammatory response to ischemia-reperfusion in diabetes.

Topics: Animals; CD11 Antigens; CD18 Antigens; Diabetes Mellitus, Experimental; Inflammation; Intercellular Adhesion Molecule-1; Leukotriene B4; Male; Myocardial Reperfusion Injury; Platelet Membrane Glycoproteins; Rats; Rats, Sprague-Dawley; Receptors, Cell Surface; Receptors, G-Protein-Coupled

The anti-inflammatory efficacy of monoterpenes is still unknown. In order to evaluate the potential role of L-menthol and mint oil as an anti-inflammatory drug, preclinical in vitro-investigations were performed using LPS-stimulated monocytes from healthy volunteers. Arachidonic acid metabolism was assessed by measuring LTB subset4 and PGE subset2 as indicators for both the lipoxygenase and the cyclooxygenase pathways respectively. In addition, the anti-inflammatory effects of the two terpenes on IL-1beta production were analysed. - L-menthol significantly suppressed the production of each of the three inflammation mediators by monocytes in vitro. LTB subset4 decreased by -64.4 +/- 10%, PGE subset2 by -56.6 +/- 8%, and IL-1beta by -64.2 +/- 7% respectively at L-menthol concentrations within the presumed therapeutic range of about 10 superset-7 g/ml. In contrast, mint oil had a bimodal effect on PGE subset2 production: lower concentrations of 10 superset-10 to 10 superset-8 g/ml increased PGE subset2 up to 6-fold compared to baseline but concentrations of 10 superset-7 g/ml suppressed PGE subset2 production by approximately 50%. Mint oil had similar effects on LTB subset4 and IL-1beta as its main constituent, L-menthol, although the degree of suppression was by comparison smaller at lower concentrations. Paraffin oil, which served as a solvent, did not affect arachidonic acid metabolism and IL-1beta production. - These results obtained with human monocytes suggest preferable anti-inflammatory effects of L-menthol compared to mint oil at therapeutically relevant concentrations supplied in enteric coated capsules. Therefore, clinical trials investigating the potential therapeutic efficacy of L-menthol for treatment of chronic inflammatory disorders such as bronchial asthma, colitis and allergic rhinitis seem worthwhile.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Dinoprostone; Drug Evaluation, Preclinical; Humans; In Vitro Techniques; Inflammation; Inflammation Mediators; Interleukin-1; Lamiaceae; Leukotriene B4; Lipopolysaccharides; Menthol; Monocytes; Plant Oils

Activated neutrophils have the ability to upregulate the expression of many genes, in particular those encoding cytokines and chemokines, and to subsequently release the corresponding proteins. Although little is known to date concerning the regulation of gene transcription in neutrophils, it is noteworthy that many of these genes depend on the activation of transcription factors, such as NF-kappaB, for inducible expression. We therefore investigated whether NF-kappaB/Rel proteins are expressed in human neutrophils, as well as their fate on cell activation. We now report that dimers consisting of p50 NFkappaB1, p65 RelA, and/or c-Rel are present in neutrophils and that the greater part of these protein complexes is physically associated with cytoplasmic IkappaB-alpha in resting cells. Following neutrophil stimulation with proinflammatory agonists (such as lipopolysaccharide [LPS], tumor necrosis factor-alpha [TNF-alpha], and fMet-Leu-Phe) that induce the production of cytokines and chemokines in these cells, NF-kappaB/Rel proteins translocated to nuclear fractions, resulting in a transient induction of NF-kappaB DNA binding activity, as determined in gel mobility shift assays. The onset of both processes was found to be closely paralleled by, and dependent on, IkappaB-alpha degradation. Proinflammatory neutrophil stimuli also promoted the accumulation of IkappaB-alpha mRNA transcripts, resulting in the reexpression of the IkappaB-alpha protein. To our knowledge, this constitutes the first indication that NF-kappaB activation may underlie the action of proinflammatory stimuli towards human neutrophil gene expression and, as such, adds a new facet to our understanding of neutrophil biology.

Topics: Base Sequence; Binding Sites; Cell Nucleus; Cells, Cultured; Cytokines; Dimerization; DNA-Binding Proteins; HIV; Humans; I-kappa B Proteins; Inflammation; Interferons; Interleukins; Leukotriene B4; Lipopolysaccharides; Monocytes; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; NF-kappa B; NF-KappaB Inhibitor alpha; Promoter Regions, Genetic; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-rel; RNA, Messenger; Tetradecanoylphorbol Acetate; Transcription Factor RelA; Transcription, Genetic; Tumor Necrosis Factor-alpha

To assess the receptors which mediate the inflammatory reaction induced by endothelin-1 (ET-1), we investigated the influence of pre-treatment with an ETA receptor antagonist (97-139) on the increase of aqueous protein concentration (APC) after the injection of ET-1 (10(-4), 10(-5)M) into the vitreous cavity of pigmented rabbits. The concentration of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) in the aqueous humor after the injection of 10(-4)M ET-1 with or without pre-treatment with 97-139 (10(-1), 10(-2), 10(-3)M) was also studied. Pre-treatment with 10(-2)M and 10(-1)M 97-139 completely prevented the APC increase induced by 10(-5)M and 10(-4)M ET-1, respectively. Increases in aqueous PGE2 concentration were observed after the injection of ET-1, which was inhibited by pre-treatment with 97-139. Aqueous LTB4 concentration was not changed significantly by ET-1. These results indicate that the effects of ET-1 on APC are at least partially mediated by the cyclooxygenase pathway of arachidonic acid cascade, and that ETA receptors play an important role in these reactions.

Topics: Animals; Anterior Chamber; Aqueous Humor; Caffeic Acids; Dinoprostone; Endothelin Receptor Antagonists; Endothelin-1; Female; Inflammation; Leukotriene B4; Male; Oleanolic Acid; Rabbits; Receptor, Endothelin A; Receptors, Endothelin; Vitreous Body

Application of leukotriene B4 (LTB4) to normal human skin induces changes similar to those found in psoriatic skin, and it has proved to be a useful model for studying the pathogenesis and treatment of psoriasis. We studied the expression patterns of molecules that have recently been shown to be altered in lesional psoriatic skin, including the extracellular matrix protein tenascin (TN) and the basement membrane and cell surface-associated heparan sulfate proteoglycans (HSPGs). During 72-h the expression of these markers was studied immunohistochemically and the expression of TN was correlated with epidermal proliferation and influx of inflammatory cells. Following the peak influx of polymorphonuclear leukocytes, a marked increase in TN expression was noted in the papillary dermis 72 h after LTB4 application. The expression patterns of basal membrane-associated epitopes of HSPG remained unaltered, whereas the expression of cell surface-associated HSPG disappeared 72 h after LTB4 application. A significant correlation was found between dermal TN expression and epidermal hyperproliferation, and between TN expression and the presence of dermal T cells. These findings indicate that the model of LTB4-induced acute cutaneous inflammation displays many characteristics of early psoriatic lesions and could serve as a model to study some of the cell biological changes in this disease.

Topics: Administration, Cutaneous; Adult; Cell Division; Dermatitis, Irritant; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Humans; Immunohistochemistry; Inflammation; Leukotriene B4; Male; Models, Biological; Proteoglycans; Psoriasis; Skin; Tenascin

The objective of this study was to determine whether genetically induced hypercholesterolemia affects leukocyte-endothelial cell interactions in postcapillary venules of the mouse cremaster muscle. Leukocyte adhesion, emigration, and other microvascular parameters were assessed in venules of normal (wild-type) and low-density lipoprotein receptor-deficient (LDLr-/-) mice maintained on either normal rodent chow or on a high cholesterol diet (HCD). Measurements were obtained under control conditions and after administration of either leukotriene B4 (LTB4), platelet-activating factor (PAF), or tumor necrosis factor-alpha (TNF-alpha). Elevated numbers of adherent and emigrated leukocytes were observed in venules of LDLr-/- (compared with wild-type) mice on HCD, both under baseline conditions and after exposure to either LTB4, PAF, or TNF-alpha. Plasma TNF-alpha levels were also elevated in LDLr-/- versus wild-type mice. Administration of blocking monoclonal antibodies demonstrated that intercellular adhesion molecule-1, but not vascular cell adhesion molecule-1, mediates the exaggerated leukocyte-endothelial cell adhesion observed in LDLr-/- mice. The results of these studies indicate that chronic hypercholesterolemia predisposes the microvasculature to intense leukocyte-endothelial cell adhesion in response to different inflammatory stimuli.

Topics: Animals; Cell Adhesion; Cell Movement; Inflammation; Leukocytes; Leukotriene B4; Mice; Mice, Knockout; Microcirculation; Muscle, Skeletal; Platelet Activating Factor; Receptors, LDL; Tumor Necrosis Factor-alpha

Sterile perforated polyethylene spheres (wiffle golf balls) were implanted s.c. in beagle dogs. A local inflammatory reaction was elicited within the spheres by injecting carrageenan. Changes in leukocyte count, prostaglandin E2, thromboxane B2 and leukotriene B4 levels were monitored in fluid samples collected over a 24-hr period. Blood samples were also collected at various time points and analyzed for prostaglandin E2 and leukotriene B4 production after ex vivo calcium ionophore treatment. Effects of standard antiinflammatory agents (aspirin, indomethacin, dexamethasone, tenidap and zileuton) and newer cyclooxygenase-2 (COX-2) selective agents (nimesulide, nabumetone and SC-58125) were determined after oral administration. Ex vivo inhibition of cyclooxygenase product synthesis (prostaglandin E2, thromboxane B2) in whole blood was used as an indicator of activity for the constitutive COX-1 isoform, although inhibition of the synthesis of these mediators in the chamber exudate during an inflammatory process is believed to represent COX-2 inhibition. Treatment effects on leukotriene B4 production were also determined both ex vivo in whole blood and in the fluid. All of the compounds tested, except aspirin, inhibited leukocyte infiltration into the fluid exudate. Inhibitors that exert their effects on both isozymes of cyclooxygenase attenuate production of cyclooxygenase metabolites in both the inflammatory exudate and in peripheral blood ex vivo, although COX-2 selective inhibitors only demonstrated activity in the exudate. A 5-lipoxygenase inhibitor (zileuton), a corticosteroid (dexamethasone) and a dual COX-2 selective/5-lipoxygenase inhibitor (RWJ 63556) had similar profiles in that they all inhibited cell infiltration and eicosanoid production in the fluid and also attenuated leukotriene B4 production in both the fluid and blood.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Cyclooxygenase Inhibitors; Disease Models, Animal; Dogs; Evaluation Studies as Topic; Female; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Sulfonamides; Thiophenes

The pathogenesis of multiple organ failure after injury is believed to involve priming and activation of the inflammatory cascade, and the polymorphonuclear neutrophil (PMN) appears to be an integral effector. Characterization of the primed PMN is evolving. Because much research has focused on the respiratory burst, the synergistic role of cytotoxic proteases, especially elastase, has been largely ignored. In addition, CD11b has been identified as pivotal in PMN-mediated tissue injury. Our hypothesis is that the well-recognized postinjury mediators platelet-activating factor (PAF) and leukotriene B4 (LTB4) prime PMNs for the concordant release of elastase and superoxide (O2-) as well as for CD11b up-regulation.. Human PMNs were isolated and then incubated with PAF or LTB4 before N-formyl-methionyl-leucyl-phenylalanine activation. O2- generation was measured by reduction of cytochrome c. Elastase was measured by cleavage of Ala-Ala-Pro-Val p-nitroanilide. CD11b expression was quantified by incubation with R-phycoerythrin-labeled monoclonal antibodies followed by flow cytometry.. PAF and LTB4 primed PMNs maximally within 5 minutes for the production of O2-, elastase release, and simultaneous up-regulation of CD11b expression on the PMN surface.. PAF and LTB4 prime human PMNs for the concordant release of elastase, generation of O2-, and CD11b up-regulation. Understanding the physiologic characteristics of PMN priming may offer new therapeutic targets to avoid the development of multiple organ failure after injury.

Topics: Humans; Inflammation; Leukocyte Elastase; Leukotriene B4; Macrophage-1 Antigen; Multiple Organ Failure; Neutrophils; Platelet Activating Factor; Respiratory Burst; Superoxides; Wounds and Injuries

Topics: Animals; Blood Proteins; Cell Adhesion; Cheek; Cricetinae; Drug Synergism; Histamine; Histamine H1 Antagonists; Inflammation; Leukocytes; Leukotriene B4; Microcirculation; Pyrilamine; Receptors, Histamine H1; Venules

Meloxicam is a new nonsteroidal anti-inflammatory drug (NSAID) derived from enolic acid. Preclinical studies have indicated that meloxicam has potent anti-inflammatory activity, together with a good gastrointestinal and renal tolerability profile. This report summarizes studies undertaken to compare meloxicam to other NSAIDs in the inhibition of the inducible cyclooxygenase (COX-2) in inflamed areas (pleurisy of the rat, peritonitis of mice) and their influence on the activity of the constitutive cyclooxygenase (COX-1) in stomach, kidney, brain, and blood. In pleurisy of the rat, meloxicam was twice as potent as tenoxicam, 3 times as potent as flurbiprofen, 8 times as potent as diclofenac, and 20 times as potent as tenidap at inhibiting prostaglandin E2 (PGE2) biosynthesis. In the peritonitis model in mice, meloxicam was approximately twice as active as piroxicam, and more than 10 times as active as diclofenac in the suppression of PGE biosynthesis. Doses of meloxicam sufficient to inhibit PGE2 biosynthesis in the pleural exudate and peritoneal exudate had no influence on leukotriene-B4 (LTB4) or leukotriene-C4 (LTC4) content. The effect of meloxicam on the PGE2 content of rat gastric juice and rat urine was weaker than that of piroxicam or diclofenac. Meloxicam was a weaker inhibitor of the increased PGE2 concentration in brain of rats and mice (induced by convulsant doses of pentetrazole) than piroxicam, diclofenac, or indomethacin. Meloxicam had a weaker effect on serum thromboxane-B2 (TXB2) concentration in rats than piroxicam or tenoxicam. The in vivo findings confirm the results of in vitro tests, conducted separately, showing that meloxicam preferentially inhibits COX-2 over COX-1. COX-2 is the inducible isoenzyme implicated in the inflammatory response, whereas COX-1 has cytoprotective effects in the gastric mucosa. Therefore, a preferential selectivity for one isoenzyme over another, as displayed by meloxicam, may have implications in the clinical setting in terms of a more favorable risk: benefit profile.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Brain; Convulsants; Cyclooxygenase Inhibitors; Dinoprostone; Female; Gastric Juice; Inflammation; Isoenzymes; Kidney; Leukotriene B4; Male; Meloxicam; Mice; Pentylenetetrazole; Pleurisy; Rats; Stomach; Thiazines; Thiazoles

In inflammatory reactions there are complex interactions of protein mediators (cytokines) and mediators derived from lipids. An important event in inflammation is superoxide production, in relation to microbicidal activity as well as tissue damage. We have studied interactions of lipid mediators with a cytokine mediator tumor necrosis factor alpha (TNF) in stimulating superoxide production by human neutrophils for this reason and because it throws light on intracellular signals activating this response. Pretreatment of neutrophils with TNF markedly augmented the amount of superoxide produced in response to AA but not to either a 20 carbon saturated fatty acid, or the hydroxy- or hydroperoxy-derivatives of AA. Not only were other polyunsaturated fatty acids (eicosapentanoic, docosahexaenoic, linolenic, linoleic acid) as effective as AA but so was the monounsaturated fatty acid, oleic acid. Indeed TNF primed the neutrophils for an increased response to a major mediator of inflammation, leukotriene B4, which is a product of AA metabolism via the lipoxygenase pathway. The data demonstrate that two major types of mediators generated during an inflammatory response have synergistic action on neutrophils in the generation of reactive oxygen species. In contrast, neutrophils primed with TNF and challenged with PGE2, a product of AA metabolism via the cyclooxygenase pathway, showed a reduced chemiluminescence response. This identifies an important interaction between unsaturated lipids and cytokines which is likely to play a critical role in disease processes and nutrient modulation of the immune responses.

Topics: Arachidonic Acid; Dinoprostone; Drug Synergism; Fatty Acids, Unsaturated; Humans; In Vitro Techniques; Inflammation; Leukotriene B4; Luminescent Measurements; Neutrophils; Reactive Oxygen Species; Recombinant Proteins; Superoxides; Tumor Necrosis Factor-alpha

An ideal form of cancer therapy is the harnessing of innate immunity to eradicate spontaneously arising clones of malignant cells. To date, attempts to develop effective immunotherapies have met with limited success. Prostaglandins and leukotrienes, collectively known as eicosanoids, are important mediators of immune and inflammatory responses. Harnessing these compounds could be a method to treat cancers. Eicosanoids are formed after cleavage of fatty acids from phospholipids by phospholipase enzymes. We have previously described, characterized and cloned a naturally occurring mammalian activator of phospholipase A2. Injection of a 24 amino acid peptide from this phospholipase A2 activating protein (PLAP), resulted in induction of an acute inflammatory response, and a concomitant regression of gliomas in rats. Administration of 500 micrograms of this protein resulted in a 50% decrease of the tumor mass within 72 h. Tumor regression coincided with a greater than twenty-fold increase in levels of prostaglandin E2(PGE2) and leukotriene B4(LTB4), and a marked infiltration of natural killer(NK) cells. These data suggest that activation of phospholipase A2 and modulation of the eicosanoid biosynthetic pathway may provide a novel therapeutic strategy for the successful treatment of malignant tumors of the nervous system.

Topics: Amino Acid Sequence; Animals; Cell Division; Dinoprostone; Dose-Response Relationship, Drug; Female; Glioma; Inflammation; Leukotriene B4; Molecular Sequence Data; Necrosis; Neoplasm Transplantation; Phospholipases A; Phospholipases A2; Proteins; Rats; Rats, Wistar; Staining and Labeling

To assess the efficacy of leukotriene synthesis inhibitors, alone and in combination with a nonsteroidal antiinflammatory drug, as potential treatments for rheumatoid arthritis (RA), using the mouse air pouch model and the collagen-induced arthritis (CIA) model.. Two selective leukotriene synthesis inhibitors, Bay x 1005 and Bay y 1015, were compared with zileuton in terms of their ability to decrease exudate volume, cell infiltration, and leukotriene B4 (LTB4) production in response to zymosan injection in the mouse air pouch model. The mouse CIA model was used to assess the effect of leukotriene synthesis inhibitors in a model of chronic inflammation. Bay y 1015 and Bay x 1005, and the cyclooxygenase inhibitor naproxen, were evaluated individually and in combination, for their antiarthritic potency in the mouse CIA model.. The results indicate that neither zileuton, Bay x 1005, nor Bay y 1015 inhibited exudate production. All 3 compounds decreased LTB4 levels in be air pouch, with Bay y 1015 being the most effective. Cell infiltration was significantly decreased with Bay x 1005, but the degree of this decrease did not appear to correlate with LTB4 levels. No inhibition of arthritis was observed with any compound administered alone. In contrast, a significant inhibition of CIA was observed in animals that received both naproxen and either Bay y 1015 or Bay x 1005.. Inhibitors of both cyclooxygenase and leukotriene synthesis in combination may be a more effective treatment of RA than either class of inhibitors alone.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Experimental; Chronic Disease; Disease Models, Animal; Drug Combinations; Exudates and Transudates; Female; Hydroxyurea; Inflammation; Leukotriene B4; Lipoxygenase; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred BALB C; Mice, Inbred DBA; Naproxen; Prostaglandin-Endoperoxide Synthases; Quinolines; Time Factors; Zymosan

Idiopathic pulmonary fibrosis (IPF) is a progressive disorder characterized by inflammation, fibroblast proliferation, and accumulation of extracellular matrix proteins. Leukotrienes (LTs) are pro-inflammatory and pro-fibrogenic mediators derived from the 5-lipoxygenase (5-LO) pathway of arachidonic acid metabolism. They are thought to play a role in a number of disease processes, but have received relatively little attention in investigations into the pathogenesis of IPF. In this study, we measured the levels of immunoreactive LTs B(4) and C(4) in homogenates of lung tissue obtained from patients with newly diagnosed, untreated IPF, as compared to levels measured in homogenates of uninvolved nonfibrotic lung tissue from patients undergoing resectional surgery for bronchogenic carcinoma. Compared to homogenates on nonfibrotic control lung, homogenates from IPF patients contained 15-fold more LTB(4) and 5-fold more LTC(4). IPF homogenate levels of LTB(4) were significantly correlated with histologic indices of both inflammation (r=0.861) and fibrosis (r=0.926). Activation of 5-LO is known from in vitro studies to be associated with localization of the enzyme at the nuclear membrane. Immunohistochemical staining for 5-LO protein in alveolar macrophages (AMs) demonstrated that such an "activated" localization pattern was significantly more frequent in IPF lung (19.2+/-3.3% of cells) than in control lung (9.3+/-0.9%); this localization pattern was rarely seen (3.2%) in sections from a truly normal transplant donor lung. Consistent with these data, AMs obtained from IPF patients by bronchoalveolar lavage, purified by adherence, and cultured in the absence of a stimulus for 16 h elaborated significantly greater amounts of LTB(4) and LTC(4) than did control AMs obtained from normal volunteers. These data indicate that the 5-LO pathway is constitutively activated in the lungs of patients with IPF, and the AM represents at least one cellular source of LT overproduction in this disorder. We speculate that LTs participate in the pathogenesis of IPF, and their overproduction in this disorder may be amenable to specific pharmacotherapy.

Topics: Adult; Aged; Arachidonate 5-Lipoxygenase; Cells, Cultured; Enzyme Activation; Female; Humans; Immunohistochemistry; Inflammation; Leukotriene B4; Leukotriene C4; Lung; Lung Neoplasms; Macrophages, Alveolar; Male; Middle Aged; Pulmonary Fibrosis; Smoking

A single class of high affinity leukotriene B4 (LTB4) receptors has been identified on the surface of guinea pig peritoneal exudate T lymphocytes. The Kd of these receptors is 1.6 nM, with a Bmax of 25.2 fmol/10(7) cells (1500 sites/cell). Receptor binding activity can be blocked by specific LTB4 receptor antagonists, but not by a specific LTD4 receptor antagonist, lipoxins A4 or B4 (LXA4, LXB4) or K252a, a protein kinase C inhibitor. Pretreatment of T lymphocytes with phorbol myristyl acetate or LXA4, reduced LTB4 receptor density in a concentration-dependent manner, although similar concentrations of LXB4 had no effect. LTB4 receptor down-modulation by LXA4 was reversed by K252a. 4 alpha-Phorbol 12,13-didecanoate, an inactive structural analogue of phorbol myristyl acetate, did not activate protein kinase C or decrease LTB4 receptor density. These results suggest that LTB4 receptor density on T cells may by ultimately down-regulated by a protein kinase C-dependent mechanism and are consistent with a physiological role of LXA4 in the modulation of inflammatory process.

Topics: Animals; Carbazoles; Female; Guinea Pigs; Hydroxyeicosatetraenoic Acids; Indole Alkaloids; Inflammation; Leukotriene B4; Lipoxins; Protein Kinase C; Receptors, Leukotriene B4; T-Lymphocytes; Tetradecanoylphorbol Acetate

1. In the zymosan rat air pouch model of inflammation we have assessed the time dependence of phospholipase A2 (PLA2) accumulation in the inflammatory exudates as well as cell migration, myeloperoxidase activity, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels. 2. A significant increase in PLA2 activity was detected in 1,200 g supernatants of exudates 8 h after injection of zymosan into rat air pouch. This event coincided with peaks in cell accumulation (mainly neutrophils) and myeloperoxidase activity in exudates and was preceded by a rise in eicosanoid levels. 3. This enzyme (without further purification) behaved as a secretory type II PLA2 with an optimum pH at 7-8 units, lack of selectivity for arachidonate release and dependence on mM calcium concentrations for maximal activity. 4. The PLA2 inhibitors manoalide and scalaradial inhibited this enzyme activity in vitro in a concentration-dependent manner. Scalaradial also inhibited zymosan stimulated myeloperoxidase release in vitro. 5. Injection of the marine PLA2 inhibitor scalaradial together with zymosan into the pouch at doses of 0.5, 1 and 5 mumol per pouch resulted in a dose-dependent inhibition of PLA2 activity in exudates collected 8 h later. Myeloperoxidase levels and cell migration were also decreased, while eicosanoid levels were not modified. 6. Colchicine administration to rats prevented infiltration and decreased PLA2 levels in the 8 h zymosan-injected air pouch. 7. These results indicate that during inflammatory response to zymosan in the rat air pouch a secretory PLA2 activity is released into the exudates. The source of this activity is mainly the neutrophil which migrates into the pouch. 8. Scalaradial exerts anti-inflammatory effects in the zymosan air pouch.

Topics: Analysis of Variance; Animals; Anti-Inflammatory Agents; Colchicine; Dinoprostone; Homosteroids; Inflammation; Leukotriene B4; Male; Neutrophils; Peroxidase; Phospholipases A; Phospholipases A2; Rats; Rats, Wistar; Sesterterpenes; Terpenes; Zymosan

Previously, we have shown that Pseudomonas aeruginosa lipase and phospholipase C (PLC), two extracellular lipolytic enzymes, interact with each other during 12-hydroxyeicosatetraenoic acid (HETE) generation from human platelets. In this regard. the addition of purified P. aeruginosa lipase to PLC-containing crude P. aeruginosa culture supernatants enhances the generation of the chemotactically active 12-HETE from human platelets. Therefore, we analyzed the interaction of purified P. aeruginosa lipase and purified hemolytic P. aeruginosa PLC with regard to inflammatory mediator release from human platelets, neutrophilic and basophilic granulocytes, and monocytes. Purified P. aeruginosa PLC, but not purified lipase by itself, induced 12-HETE generation from human platelets, the generation of leukotriene B4 (LTB4) and oxygen metabolites, enzyme release from human neutrophils, and histamine release from basophils but diminished interleukin-8 (IL-8) release from human monocytes in a dose-dependent manner. The addition of purified lipase enhanced PLC-induced 12-HETE and LTB4 generation, did not influence enzyme, histamine, or IL-8 release, but diminished the PLC-induced chemiluminescent response. Similar results were obtained when the hemolytic PLC from Clostridium perfringens was used instead of P. aeruginosa PLC. For further comparison, we used the well-defined calcium ionophore A23187 and phorbol-12-myristate-13-acetate (PMA) as stimuli. Lipase enhanced calcium ionophore-induced LTB4 generation and beta-glucuronidase release but reduced calcium ionophore-induced and PMA-induced chemiluminescence. In parallel, we analyzed the role of lipase in a crude P. aeruginosa culture supernatant containing PLC and lipase. Lipase activity in the P. aeruginosa culture supernatant was inhibited by treatment with the lipase-specific inhibitor hexadecylsulfonyl fluoride, leaving the activity of PLC unaffected. The capacity of "lipase-inactivated culture supernatant" to induce 12-HETE and LTB4 generation was diminished by 50 to 100%. Our results suggest that the simultaneous secretion of lipase and PLC by P. aeruginosa residing in an infected host may result in severe pathological effects which cannot be explained by the sole action of the individual virulence factor on inflammatory effector cells.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Basophils; Blood Platelets; Chemotaxis, Leukocyte; Enzymes; Histamine; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Interleukin-8; Leukocytes; Leukotriene B4; Lipase; Luminescent Measurements; Monocytes; Neutrophils; Pseudomonas aeruginosa; Type C Phospholipases

Eosinophils are thought to be one of the pathophysiologically pivotal cells in atopic-type inflammation. In the present experiments, the in vitro responsiveness to stimuli of eosinophils, which had infiltrated into the airway following intravenous administration of Sephadex G-200 (Sephadex), was mainly studied in non-sensitized and [antigen + Al(OH)3]-sensitized guinea pigs. In sensitized, Sephadex-treated guinea pigs, a large number of eosinophils were found in the bronchoalveolar lavage fluid, whereas a much smaller number of cells were recovered in either non-sensitized or sensitized, Sephadex-untreated animals and a smaller number were recovered in non-sensitized Sephadex-treated animals. The eosinophils from non-sensitized Sephadex-treated guinea pigs released superoxide anion (.O2-) and thromboxane (TX) B2 in response to platelet-activating factor (PAF), leukotriene B4 and Ca ionophore A23187. Either spontaneous or PAF-induced .O2- generation from eosinophils of sensitized, Sephadex-treated guinea pigs was significantly greater than that from non-sensitized animals, while TXB2 release stimulated by any of the above stimuli was not further enhanced by sensitization. These results indicate that active sensitization can change some eosinophil functions and that the functionally altered cells could play a pathophysiological role in atopic inflammation.

Topics: Aluminum Hydroxide; Animals; Antigens; Bronchoalveolar Lavage Fluid; Calcimycin; Dextrans; Eosinophils; Gels; Guinea Pigs; Indicators and Reagents; Inflammation; Injections, Intraperitoneal; Injections, Intravenous; Ionophores; Leukocyte Count; Leukotriene B4; Male; Passive Cutaneous Anaphylaxis; Platelet Activating Factor; Respiratory System; Superoxides; Thromboxane B2

Airway obstruction, as measured by increases in postmortem pulmonary gas trapping, and lung inflammatory changes were examined in guinea pigs exposed for up to 4 h to aerosols of leukotriene B4 (LTB4) or its non-chemotactic isomer, 6-trans-12-epi-LTB4. Airway obstruction and cytological responses in isomer-exposed animals were similar to those of unexposed control animals. LTB4-exposed animals had minimal inflammatory changes at 0.5 h but became dyspneic by 2 h and had increased airway obstruction, bronchoalveolar lavage neutrophils and eosinophils, and pulmonary tissue granulocyte scores. The LTB4-induced effects at 4 h were similar to those 2 h, except for further increase in BAL neutrophils and eosinophils. LTB4-induced airway obstructive and inflammatory changes were prevented by pretreatment with the LTB4 receptor antagonist SC-41930, but were unaffected by indomethacin. Thus, prolonged LTB4 inhalation can produce delayed onset airway obstruction that is stereospecific, cyclooxygenase-independent, and temporally associated with the influx of granulocytes into lung airways.

Topics: Aerosols; Airway Obstruction; Animals; Anti-Inflammatory Agents, Non-Steroidal; Benzopyrans; Bronchoalveolar Lavage; Cyclooxygenase Inhibitors; Granulocytes; Guinea Pigs; Inflammation; Leukotriene B4; Lung; Lung Volume Measurements; Male; Microscopy; Receptors, Leukotriene B4; Stereoisomerism

Inhalation of antigen in immunized mice induces an infiltration of eosinophils into the airways and increased bronchial hyperreactivity as are observed in human asthma. We employed a model of late-phase allergic pulmonary inflammation in mice to address the role of leukotrienes (LT) in mediating airway eosinophilia and hyperreactivity to methacholine. Allergen intranasal challenge in OVA-sensitized mice induced LTB4 and LTC4 release into the airspace, widespread mucus occlusion of the airways, leukocytic infiltration of the airway tissue and broncho-alveolar lavage fluid that was predominantly eosinophils, and bronchial hyperreactivity to methacholine. Specific inhibitors of 5-lipoxygenase and 5-lipoxygenase-activating protein (FLAP) blocked airway mucus release and infiltration by eosinophils indicating a key role for leukotrienes in these features of allergic pulmonary inflammation. The role of leukotrienes or eosinophils in mediating airway hyperresponsiveness to aeroallergen could not be established, however, in this murine model.

Topics: 5-Lipoxygenase-Activating Proteins; Allergens; Animals; Asthma; Bronchial Provocation Tests; Bronchoconstrictor Agents; Carrier Proteins; Disease Models, Animal; Female; Immunoglobulin E; Inflammation; Leukotriene B4; Leukotriene C4; Lipoxygenase Inhibitors; Membrane Proteins; Methacholine Chloride; Mice; Mice, Inbred BALB C; Mucus; Ovalbumin; Pulmonary Eosinophilia; Respiratory Function Tests; Respiratory System

Topics: Anti-Inflammatory Agents; Cell Nucleus; Cyclooxygenase 2; Drug Design; Eicosanoids; Gene Expression Regulation, Enzymologic; Humans; Inflammation; Inflammation Mediators; Isoenzymes; Leukotriene B4; Membrane Proteins; Prostaglandin-Endoperoxide Synthases; Receptors, Cytoplasmic and Nuclear; Signal Transduction; Transcription Factors

Inflammation is a local immune response to 'foreign' molecules, infection and injury. Leukotriene B4, a potent chemotactic agent that initiates, coordinates, sustains and amplifies the inflammatory response, is shown to be an activating ligand for the transcription factor PPARalpha. Because PPARalpha regulates the oxidative degradation of fatty acids and their derivatives, like this lipid mediator, a feedback mechanism is proposed that controls the duration of an inflammatory response and the clearance of leukotriene B4 in the liver. Thus PPARalpha offers a new route to the development of anti- or pro-inflammatory reagents.

Topics: Adaptation, Physiological; Animals; Arachidonic Acid; Cells, Cultured; Chloramphenicol O-Acetyltransferase; Fatty Acids; Female; Gene Expression Regulation; HeLa Cells; Humans; Inflammation; Inflammation Mediators; Leukotriene B4; Ligands; Liver; Male; Mice; Oxidation-Reduction; Plasmids; Pyrimidines; Rats; Rats, Sprague-Dawley; Receptors, Cytoplasmic and Nuclear; Time Factors; Transcription Factors; Transfection

The effects of bakuchiol, a meroterpenoid isolated from the leaves of Psoralea glandulosa L., on phospholipase A2 (PLA2) activity from different sources, human neutrophil responses, zymosan air pouch and topical inflammation in mice, were investigated. This natural product was a weak inhibitor of secretory and intracellular PLA2 but dose-dependently reduced the formation of LTB4 and TXB2 by human neutrophils and platelet microsomes, respectively. In addition, bakuchiol inhibited degranulation in human neutrophils, whereas superoxide generation was not affected. In mice, bakuchiol decreased cell migration, myeloperoxidase activity and eicosanoid levels in the air pouch inflammation induced by zymosan. After topical administration, this compound was effective as an inhibitor of oedema and myeloperoxidase activity in the 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced ear oedema and significantly reduced the PGE2 content and ear oedema in the arachidonic acid-induced response. Bakuchiol is a natural anti-inflammatory agent able to control leukocytic functions such as eicosanoid production, migration and degranulation in the inflammatory site.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Survival; Dinoprostone; Edema; Humans; In Vitro Techniques; Inflammation; Leukocyte Elastase; Leukocytes; Leukotriene B4; Male; Mice; Neutrophils; Peroxidase; Phenols; Phospholipases A; Phospholipases A2; Superoxides; Thromboxane B2; Zymosan

This paper describes the use of subcutaneously-placed tissue chambers as a sterile soft-tissue inflammation model in Thoroughbred horses. Acute, non-immune inflammation was initiated by injecting a sterile lambda carrageenan solution into a tissue chamber. This model was used to study the temporal changes in oxygen and carbon dioxide tensions, pH, bicarbonate, protein, albumin, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) concentrations, cell counts and differential counts in tissue fluid from inflamed tissue chambers and control chambers. Skin temperatures over control and inflamed chambers were also compared. Carrageenan-induced inflammation resulted in significant increases in tissue-fluid carbon dioxide tension, leucocyte count, albumin, and PGE2 and LTB4 concentrations. It also resulted in a significant decrease in tissue fluid pH and HCO3-concentration. Inflammation did not result in significant changes in tissue-fluid protein concentration, differential cell counts or skin temperature over the chambers. The use of this type of tissue chamber is well-suited for studying the pathophysiology of a self-contained, non-immune inflammatory process. The model described in this paper could prove to be very useful in studies of the distribution of anti-inflammatory drugs and the effects of such drugs on various aspects of the inflammatory process.

Topics: Animals; Bicarbonates; Carbon Dioxide; Diffusion Chambers, Culture; Dinoprostone; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Exudates and Transudates; Female; Horse Diseases; Horses; Hydrogen-Ion Concentration; Inflammation; Leukocyte Count; Leukotriene B4; Oxygen Consumption; Proteins; Skin Temperature; Soft Tissue Infections; Software

Topics: Bronchoalveolar Lavage Fluid; Bronchopulmonary Dysplasia; Complement C5a; Humans; Infant, Low Birth Weight; Infant, Newborn; Inflammation; Inflammation Mediators; Intercellular Adhesion Molecule-1; Interleukin-8; Leukotriene B4; Pancreatic Elastase

The marine metabolites pacifenol, stypotriol triacetate and epitaondiol were tested for their effects on a number of inflammatory responses. Epitaondiol exhibited a potent topical anti-inflammatory activity related to inhibition of leukocyte accumulation. The other compounds showed a lower potency, similar to that of indomethacin. None of the compounds affected superoxide generation by human neutrophils but pacifenol effectively inhibited the degranulation response. This compound and epitaondiol decreased the release of eicosanoids with a higher potency on the cyclo-oxygenase pathway. Only epitaondiol inhibited human recombinant synovial phospholipase A2 activity in a concentration-dependent manner.

Topics: Animals; Anti-Inflammatory Agents; Anti-Inflammatory Agents, Non-Steroidal; Blood Platelets; Calcimycin; Cytochrome c Group; Ear, External; Edema; Humans; Inflammation; Leukotriene B4; Mice; Neutrophils; Oxidation-Reduction; Phospholipases A; Phospholipases A2; Sesquiterpenes; Steroids; Stimulation, Chemical; Superoxides; Terpenes; Tetradecanoylphorbol Acetate; Thromboxane B2

The changing levels of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) were compared over a period of 1 h to 15 days in two kinds of inflammatory responses induced in the rat air pouch by chemically similar polymers of peptidoglycan-polysaccharide (PG-PS) isolated from cell walls of group A streptococci. The smaller polymers (100 s, average mol. wt 5.3 x 10(6)) induced a more severe acute response over the first 24 h, whereas, from 3 to 15 days the larger polymers (10 p, average mol. wt 5 x 10(8)) induced greater chronic inflammation, as measured by pouch fluid volume, number of infiltrating cells and weight of granulation tissue. The most prominent difference between the two kinds of responses in the pattern of PGE2 and LTB4 were: (a) A shift between 1 to 6 h to much higher production of PGE2 in the exudate induced by large polymers. During this time the level of LTB4 also increased, but continued to be higher in the exudate induced by small polymers. (b) The sustained production of relatively high levels of LTB4 and PGE2 in the large polymer exudate at 15 days. Changes such as these indicate that this model is useful for analyzing mediators which regulate the evolution of acute into chronic inflammation.

Topics: Acute Disease; Animals; Cell Wall; Chronic Disease; Dinoprostone; Enzyme-Linked Immunosorbent Assay; Female; Granulation Tissue; Granuloma; Inflammation; Leukotriene B4; Molecular Weight; Peptidoglycan; Rats; Rats, Inbred Lew; Streptococcus pyogenes

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Acrylates; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Calcium; Cell Line; Edema; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Pyridines; Receptors, Leukotriene B4; Tumor Cells, Cultured

Topics: Animals; Guinea Pigs; Inflammation; Leukotriene B4; Leukotrienes; Lung; Male; Metiamide; Ovalbumin; Pyrilamine; Quinolines

Topics: Animals; Humans; Inflammation; Leukotriene B4; Leukotriene D4; Lipid Metabolism; Lipoxygenase Inhibitors; Tumor Necrosis Factor-alpha

A comparative study in horses of the pharmacokinetics (PK) and pharmacodynamics (PD) of 2 extensively used nonsteroidal anti-inflammatory drugs (NSAIDs), flunixin (FXN) and ketoprofen (KTP), was carried out applying PK/PD modelling. To evaluate the anti-inflammatory properties of these drugs a model of acute inflammation, comprising surgically implanted subcutaneous tissue cages stimulated by intracaveal injection of carrageenan, was used. FXN elimination half-life (T1/2 beta) in plasma was 3.37 +/- 1.09 h. However, in exudate a much longer T1/2 beta was obtained (15.99 +/- 3.80 h). Apparent volume of distribution (Vdarea) for FXN was 0.317 +/- 0.126 l/kg and body clearance (ClB) was 0.058 +/- 0.004 l/kg/h. KTP displayed enantioselective pharmacokinetics, the S(+) enantiomer being predominant in plasma, exudate and transudate. T1/2 beta values for R(-) and S(+)KTP were, respectively, 1.09 +/- 0.19 h and 1.51 +/- 0.45 h (plasma) and 19.73 +/- 2.72 h and 22.64 +/- 4.34 h (exudate), respectively. R(-)KTP was cleared more rapidly than the S(+) enantiomer. ClB values were 0.277 +/- 0.035 l/kg/h and 0.202 +/- 0.022 l/kg/h, respectively. FXN and KTP pharmacodynamics was evaluated by determining their inhibitory effects on serum thromboxane (Tx)B2, exudate prostaglandin (PG)E2, leukotriene (LT)B4 and beta-glucuronidase (beta-glu) and intradermal bradykinin-induced swelling. Both drugs produced marked inhibition of serum TxB2 synthesis for up to 24 h, with no significant differences between the drugs. FXN was a more potent inhibitor of exudate PGE2, the EC50 for FXN being lower (P < 0.01) than that for KTP (0.019 +/- 0.010 microgram/ml and 0.057 +/- 0.009 microgram/ml, respectively). Neither drug had any effect on exudate LTB4 concentration. Differences between the 2 drugs were observed for the inhibition of beta-glu, the Emax for KTP being higher (P < 0.01) than for FXN. However, no differences were observed in other PD parameters. Both FXN and KTP inhibited bradykinin-induced swelling. Differences between the drugs were obtained for Emax, which was greater for FXN (P < 0.01) than for KTP. Equilibration half-life (T1/2Ke0) also differed, being much longer (P < 0.01) for FXN than for KTP. PK/PD modelling proved to be a useful and novel analytical technique for studying the pharmacodynamics of NSAIDs, with the advantage over classical in vitro methods that it provides data in the whole animal. By quantifying action-concentration interrelationships through PK-PD mod

Topics: Acute Disease; Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Clonixin; Cross-Over Studies; Dinoprostone; Exudates and Transudates; Glucuronidase; Half-Life; Horses; Inflammation; Ketoprofen; Leukotriene B4; Male; Models, Biological; Thromboxane B2

The effects of 2-(2-(4-(diphenylmethyl)-1-piperadinyl) ethoxy) benzoic acid malate (ZCR-2060) on allergic airway inflammation and inflammatory cell activation in guinea-pigs were studied. Allergic airway inflammation was induced by inhalation of antigen into actively-sensitized animals and the increase in inflammatory cells into bronchoalveolar lavage fluid (BALF) was measured. Aeroantigen-induced infiltration of inflammatory cells, especially eosinophils and neutrophils, in BALF gradually increased, and reached a peak at 6 or 9 h after the challenge. ZCR-2060 (1 mg kg-1 p.o.) clearly inhibited the increase of eosinophil numbers in BALF. Moreover, the effect of ZCR-2060 on inflammatory cell activation in terms of chemotaxis and superoxide generation in-vitro was studied. ZCR-2060 (10(-6)-10(-4) M) inhibited the platelet-activating factor (PAF)-induced chemotaxis of eosinophils and neutrophils, but did not inhibit the leukotriene B4-induced chemotaxis of eosinophils and the formyl-Met-Leu-Phe-induced chemotaxis of neutrophils. PAF-induced superoxide anion generation by eosinophils, neutrophils and alveolar macrophages was inhibited by ZCR-2060 (10(-6)-10(-4) M). However, ZCR-2060 did not affect phorbol myristate acetate-induced superoxide anion generation by eosinophils, neutrophils and alveolar macrophages. These results indicate that ZCR-2060 inhibits allergic airway inflammation, and PAF-induced inflammatory cell activation in guinea-pigs. ZCR-2060 may prove useful for the treatment of allergic airway inflammation or allergic disorders, especially inflammatory cell infiltration and activation.

Topics: Animals; Benzoates; Bronchoalveolar Lavage Fluid; Chemotaxis, Leukocyte; Eosinophils; Guinea Pigs; Inflammation; Leukotriene B4; Macrophages, Alveolar; Male; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Piperidines; Platelet Activating Factor; Respiratory Hypersensitivity; Superoxides; Tetradecanoylphorbol Acetate

Several lines of evidence have suggested that specific (i.e., lymphocyte) immunity plays a role in chemical-induced pulmonary diseases, including asbestosis. To evaluate the influence of cell-mediated immunity in pulmonary inflammation and fibrosis evoked by asbestos fibers, we compared the effects of asbestos in immunodeficient mice (Balb/c nu/nu and severe combined immunodeficient [C3H-SCID]), immunologically normal mice of the same genetic background, and immunodeficient mice reconstituted with syngeneic T lymphocytes. Increases in lavaged cell numbers occurred in asbestos-treated immunodeficient mice compared with asbestos-treated immunocompetent or immunodeficient mice that received T lymphocytes. Differential analysis of the collected cells in treated mice demonstrated a predominantly neutrophilic infiltrate that correlated with increased levels of leukotriene B4 and prostaglandin E2. There were no significant differences between immunocompetent and athymic asbestos-treated mice in bronchoalveolar lavaged total protein. However, asbestos-treated SCID mice revealed a significant increase in protein content and lactate dehydrogenase activity compared with asbestos-treated normal mice, which did not occur in T lymphocyte-reconstituted SCID mice. Fibronectin levels were elevated in asbestos-exposed athymic mice when compared with air-exposed athymic mice or asbestos-exposed immunocompetent mice. Both asbestos-treated athymic and SCID mice showed a significant increase in total lung hydroxyproline when compared with asbestos-treated immunocompetent mice. Lung hydroxyproline was also reduced in asbestos-exposed SCID mice after T lymphocyte reconstitution and, conversely, increased in T cell-depleted Balb/c mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Asbestos, Serpentine; Asbestosis; Base Sequence; Bronchoalveolar Lavage Fluid; Collagen; Dinoprostone; Fibronectins; Hydroxyproline; Inflammation; Interferon-gamma; L-Lactate Dehydrogenase; Leukotriene B4; Lung; Mice; Mice, Inbred Strains; Mice, Nude; Mice, SCID; Molecular Sequence Data; Pulmonary Fibrosis; RNA, Messenger; T-Lymphocytes

In mouse skin in vivo the irritant and hyperplasiogenic tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) strongly increased the epidermal content of the cysteinyl leukotrienes LTC4, LTD4 and LTE4, but not of leukotriene LTB4. This effect was completely suppressed by the selective leukotriene biosynthesis inhibitor MK-886. Intragastric administration of MK-886 prevented phorbol ester-induced ear edema, but not epidermal hyperproliferation and tumor promotion. These data indicate that leukotrienes are involved in the pro-inflammatory effects of the phorbol ester, whereas its hyperproliferative and tumor-promoting activities do not depend on 5-lipoxygenase-catalyzed leukotriene formation. This action differs from several non-selective inhibitors of lipoxygenases that were found to inhibit tumor promotion in initiated mouse skin.

Topics: Animals; Ear, External; Edema; Epidermis; Female; Hyperplasia; Indoles; Inflammation; Leukotriene B4; Mice; Skin Neoplasms; SRS-A; Tetradecanoylphorbol Acetate

We used the 5-lipoxygenase-activating protein (FLAP) antagonist MK-0591 to investigate the importance of leukotrienes (LT) in causing ozone-induced bronchoconstriction, airway inflammation, and airway hyperresponsiveness in dogs. Six random source dogs were studied. On one day, dogs were treated with MK-0591 (2 mg/kg iv) followed by a continuous intravenous infusion of 8 micrograms.kg-1.min-1. On the other day, the diluent was infused. Acetylcholine airway responsiveness was measured before and 1 h after ozone inhalation (3 ppm for 30 min). On each day, whole blood and bronchoalveolar lavage (BAL) cells were challenged with calcium ionophore to stimulate LTB4 production. Urinary LTE4 levels were measured before and after ozone. MK-0591 inhibited LTB4 production in whole blood by 96% (P = 0.001) and that from BAL cells by 91% (P = 0.001). By contrast, MK-0591 had no effect on ozone-induced bronchoconstriction, airway hyperresponsiveness, or influx of neutrophils into BAL. The mean log difference of the pre- to post-acetylcholine provocative concentration was 0.64 +/- 0.40 during MK-0591 treatment and 0.68 +/- 0.40 during diluent treatment (P = 0.71). These results indicate that peptidoleukotrienes are produced during ozone inhalation and that MK-0591 inhibits LT production in dogs. However, LTs do not play a role in ozone-induced bronchoconstriction, airway inflammation, or airway hyperresponsiveness in dogs.

Topics: 5-Lipoxygenase-Activating Proteins; Acetylcholine; Airway Resistance; Animals; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Carrier Proteins; Dogs; Indoles; Inflammation; Leukotriene Antagonists; Leukotriene B4; Leukotriene E4; Leukotrienes; Lipoxygenase Inhibitors; Membrane Proteins; Ozone; Quinolines; Respiratory System

Gouty inflammation can be suppressed by an iron chelator. We therefore hypothesized that arthritis associated with sodium urate crystal deposition could follow the incomplete complexation of iron cation with subsequent oxidant generation as the metal cycles through reduced and oxidized states. Urate crystals adsorbed Fe3+ in vitro and crystals collected from a human tophus had significant concentrations of ionizable iron. Urate crystals oxidized deoxyribose to a thiobarbituric acid (TBA)-reactive product, augmented luminol chemiluminescence by neutrophils, released leukotriene B4 from neutrophils, activated complement, and promoted neutrophil chemotaxis. All of these events increased with the concentration of complexed iron and were suppressed by the iron chelator deferoxamine or the .OH scavenger dimethylthiourea. These results suggest that some portion of gouty inflammation after urate crystal deposition could result from the incomplete complexation of iron with subsequent catalytic generation of reactive oxygen species.

Topics: Chemotaxis, Leukocyte; Chlorides; Complement Activation; Crystallization; Deferoxamine; Ferric Compounds; Gout; Humans; In Vitro Techniques; Inflammation; Iron; Kinetics; Leukotriene B4; Neutrophils; Uric Acid

The neuropeptide alpha-melanocyte-stimulating hormone (alpha-MSH) has potent antipyretic and antiinflammatory properties. When administered systemically, the naturally occurring molecule and its COOH-terminal tripeptide sequence inhibit inflammation induced by peripherally applied irritants and intradermal injections of mediators of inflammation such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF alpha). We recently found that alpha-MSH can act solely within the brain to inhibit inflammation caused by a general irritant applied to the skin. This activity appears to be shared with salicylate drugs and the combined observations suggest the existence of descending neurogenic antiinflammatory signals capable of modulating inflammation in peripheral tissues. To improve our knowledge of the scope of this action of the peptide, alpha-MSH was injected into the cerebral ventricles (i.c.v.) of mice that had received intradermal injections in the ear of mediators of inflammation: IL-1 beta, IL-8, leukotriene B4, and platelet-activating factor. The centrally administered peptide inhibited the actions of all of these proinflammatory agents as determined from comparisons with measures of ear edema over time in control animals; this indicates that the central peptide can alter inflammation induced in the periphery by major mediators of inflammation. In tests confined to IL-1 beta, central administration of alpha-MSH(11-13) was also effective. These findings support the concept of a descending neurogenic antiinflammatory influence promoted by an action of alpha-MSH within the brain, an inhibitory influence that is not restricted to modulation of just one or a limited set of the mediators of inflammation.

Topics: alpha-MSH; Animals; Anti-Inflammatory Agents, Non-Steroidal; Cytokines; Edema; Female; Inflammation; Injections, Intraventricular; Interleukin-1; Interleukin-8; Leukotriene B4; Mice; Mice, Inbred BALB C; Platelet Activating Factor

CI-986 is a potent inhibitor of 5-lipoxygenase and cyclooxygenase pathway product biosynthesis from rat basophilic leukemia (RBL) cells. Because metabolites from these pathways have proinflammatory properties, CI-986 was evaluated in several acute and chronic models of inflammation and hyperalgesia. The compound inhibited swelling in the carrageenan footpad edema, Mycobacterium foot-pad edema and adjuvant arthritis models of inflammation with ID40 values of 1.0, 7.7., and 7.2 mg/kg, respectively. It was roughly equivalent in potency to the standard selective cyclooxygenase inhibitor, naproxen (ID40 = 0.7, 6.3, and 3.8 mg/kg, respectively). CI-986 was also evaluated in the acetic acid induced writhing hyperalgesia assay (ID50 = 0.23 mg/kg) and was approximately equipotent with indomethacin (ID50 = 0.87 mg/kg). Although the effects of CI-986 were similar to those of standard nonsteroidal antiinflammatory drugs (NSAIDs) in the inflammation models, its gastrointestinal profile was unique. CI-986 caused no gastrointestinal irritation at doses up to 200 mg/kg in acute and chronic studies. In contrast, standard NSAIDs caused ulcers at doses of 3.7-37 mg/kg after a single dose. Moreover, CI-986 inhibited the release of LTC4 and PGE2 by gastric mucosa and reduced mucosal and vascular damage induced by oral administration of absolute ethanol to rats. These results indicate that CI-986 is a potent nonulcerogenic antiinflammatory agent with novel pharmacologic properties.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Arthritis, Experimental; Cyclooxygenase Inhibitors; Dinoprost; Disease Models, Animal; Ethanol; Female; Gastritis; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice; Pain; Rats; Rats, Wistar; Thiadiazoles; Tumor Cells, Cultured

Bronchopulmonary dysplasia (BPD) of preterm neonates is associated with an increased recruitment of inflammatory cells into the airways. To evaluate further the role of inflammation in the pathogenesis of BPD, tracheobronchial aspirate fluid of neonates with birth weight < 1200 g (n = 59) was sequentially analyzed in a prospective study.. Tracheobronchial aspirate fluid was assessed for chemotactic activity, neutrophil cell count, concentrations of elastase-alpha 1-proteinase inhibitor and activity of free elastase, concentrations of chemoattractants (complement component C5-derived anaphylatoxin, leukotriene B4, interleukin-8), and albumin concentrations as well as alpha 1-proteinase inhibitor activity. The secretory component for immunoglobulin A was used as reference protein. Only specimens without evidence of microbiological colonization were studied.. In neonates with prolonged respiratory disease (BPD-risk neonates, n = 24, fraction of inspired oxygen > or = 0.3 and/or peak inspiratory pressure > or = 16 cm H2O at day 10 postnatal age, birth weight 892 +/- 36 g, gestational age 27.2 +/- 0.3 weeks) chemotactic activity, cell count, concentrations of the chemoattractants complement component C5-derived anaphylatoxin, leukotriene B4, interleukin-8, as well as levels of elastase-alpha 1-proteinase inhibitor were significantly higher at day 10 and/or day 15 of postnatal age compared with neonates without chronic pulmonary disease (total n = 35; day 10, n = 11; day 15, n = 8). There was no difference in free elastolytic activity. Concentrations of albumin as well as alpha 1-proteinase inhibitor activity were higher in BPD-risk patients on day 15, indicating an increased pulmonary leak.. We conclude that preterm neonates at risk for the development of BPD show an enhanced inflammatory reaction in the lungs and an associated increase in pulmonary microvascular permeability. We speculate that inflammation may play an important role in the pathogenesis of BPD.

Topics: Albumins; alpha 1-Antitrypsin; Bronchopulmonary Dysplasia; Capillary Permeability; Chemotaxis, Leukocyte; Humans; Infant, Low Birth Weight; Infant, Newborn; Infant, Premature; Inflammation; Interleukin-8; Leukocyte Count; Leukotriene B4; Lung; Neutrophils; Pancreatic Elastase; Prospective Studies; Respiratory Distress Syndrome, Newborn; Risk Factors

The objective of this study was to determine whether exposure to ozone causes inflammatory or functional changes in the upper or lower airways of asthmatic and nonasthmatic individuals. Ten asthmatic and eight nonasthmatic subjects were exposed to clean air, 120 ppb ozone, or 240 ppb ozone for 90 min during intermittent moderate exercise using a head dome exposure system. Pulmonary function tests, posterior rhinomanometry, and nasal lavage were performed before and after exposure. Leukocyte counts and chemotactic factors leukotriene B4 (LTB4), platelet-activating factor (PAF), and interleukin-8 (IL-8) were analyzed from nasal lavage fluid. In subjects with asthma, a significant increase (p < 0.05) in the number of white blood cells in lavage fluid was detected both immediately and 24 h after exposure to 240 ppb ozone, as was a significant increase in epithelial cells immediately after exposure (p < 0.05). No significant cellular changes were seen in nonasthmatic subjects. A significant correlation was observed between IL-8 and white blood cells counts after exposure to 240 ppb ozone (r = 0.76) in asthmatic subjects. No significant changes in pulmonary or nasal function or biochemical mediators were found in either the asthmatic or nonasthmatic subjects. These data indicate that asthmatic individuals are more sensitive to the acute inflammatory effects of ozone than nonasthmatic individuals.

Topics: Adolescent; Adult; Asthma; Female; Histamine; Humans; Inflammation; Interleukin-8; Leukocyte Count; Leukotriene B4; Male; Nasal Lavage Fluid; Ozone; Platelet Activating Factor; Respiratory Mechanics; Respiratory System

Sickle cell (HbSS) disease is associated with rheological and inflammatory stresses within the microcirculation. In order to determine the role of leukotrienes in the inflammatory processes in HbSS patients, we analysed plasma and urine levels of leukotrienes (LT); LTB4, LTC4, LTD4, and LTE4 as indicators of their in vivo metabolism. Plasma and urine level samples of 15 HbSS patients in steady-state and age-matched healthy, homozygous (HbAA) controls were extracted for leukotrienes and quantitated by HPLC. Control plasma level of leukotrienes (mean +/- SEM, ng ml-1) were: LTB4, 8.95 +/- 0.26; LTC4, 7.24 +/- 0.21; LTD4, 11.42 +/- 0.40; and LTE4, 14.51 +/- 0.50. Corresponding values for HbSS patients were: LTB4, 6.15 +/- 0.42; LTC4, 13.61 +/- 1.45; LTD4, 6.44 +/- 0.51 and LTE4, 4.97 +/- 0.37. The differences were significant at P < 0.05. Urine levels (mean +/- SEM, ng mmol-1 creatinine), for controls were: LTB4, 10.60 +/- 0.35; LTC4, 360.0 +/- 9.82. Values for HbSS urine were: LTB4, 27.50 +/- 3.33; LTC4, 356.0 +/- 17.87; LTD4, 69.90 +/- 14.51. LTD4 was not detected in control urine. These results suggest that sickle cell patients may exhibit impaired ability to catabolize LTC4 in plasma during steady state conditions. This altered metabolism may contribute to the persistent stress of the microcirculation, and is probably related to the abnormal microvascular rheology of sickle blood cells.

Topics: Adult; Anemia, Sickle Cell; Cell Adhesion; Endothelium, Vascular; Female; Humans; Inflammation; Leukocytes; Leukotriene B4; Leukotriene C4; Leukotriene D4; Leukotriene E4; Leukotrienes; Male; Middle Aged

The antiinflammatory activity of rolipram, a selective inhibitor of the cyclic AMP-specific phosphodiesterase (PDE IV), was studied. Rolipram did not inhibit 5-lipoxygenase activity but did inhibit human monocyte production of leukotriene B4 (LTB4, IC50 3.5 microM). Likewise, murine mast cell release of leukotriene C4 and histamine was inhibited. In vivo, rolipram inhibited arachidonic acid-induced inflammation in the mouse, while the low Km-cyclic-GMP PDE inhibitor, zaprinast, did not inhibit. Rolipram had a modest effect on LTB4 production in the mouse, but markedly reduced LTB4-induced PMN infiltration. Beta-adrenergic receptor activation of adenylate cyclase was important for rolipram antiinflammatory activity since beta blockade abrogated arachidonic acid-induced inflammation. Thus, the antiinflammatory profile of rolipram is novel and may result from inhibition of PMN function and perhaps vasoactive amine release and leukotriene biosynthesis. These actions may be dependent upon endogenous beta-adrenergic activity and are likely mediated through inhibition of PDE IV.

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Calcimycin; Cells, Cultured; Colforsin; Cyclic Nucleotide Phosphodiesterases, Type 4; Ear, External; Eicosanoids; Histamine Release; Humans; Imidazoles; Inflammation; Leukotriene B4; Male; Mast Cells; Mice; Mice, Inbred BALB C; Monocytes; Nadolol; Naproxen; Neutrophils; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases; Purinones; Pyrazoles; Pyrrolidinones; Receptors, Adrenergic, beta; Rolipram; SRS-A; Thiazoles

Fluid filtration rate with respect to surface area (Jv/S) was measured in capillaries of rat mesentery by a micro-occlusion technique. Superfusion of the mesentery with 100 nM platelet-activating factor (PAF) caused a fivefold increase in Jv/S (control, mean +/- SE = 0.016 +/- 0.002 micron/s, n = 44 rats; PAF, 0.078 +/- 0.010, n = 10), whereas 20 nM leukotriene B4 (LTB4) had no effect (0.010 +/- 0.003, n = 8). These doses of PAF and LTB4 induced a similar level of leukocyte adherence to venular endothelium. Neutrophils play a role in PAF-mediated increases in Jv/S, since a significantly lower Jv/S was elicited by PAF superfusion in neutropenic rats (0.024 +/- 0.006, n = 7). Monoclonal antibodies (MAb) directed against either the leukocyte adhesion glycoprotein CD11/CD18 (0.037 +/- 0.006, n = 8) or the endothelial cell adhesion molecule P-selectin (0.025 +/- 0.004, n = 8) also attenuated PAF-induced capillary filtration, whereas a nonbinding form of the P-selection MAb had no inhibitory effect (0.066 +/- 0.024, n = 3). These results indicate that PAF, but not LTB4, enhances capillary fluid filtration rate. While neutrophils do not adhere to endothelium in capillaries exposed to PAF, they do appear to contribute significantly to the PAF-induced capillary fluid filtration.

Topics: Animals; Antibodies, Monoclonal; Antigens, CD; Capillaries; CD11 Antigens; CD18 Antigens; Cell Adhesion; Endothelium, Vascular; Filtration; Inflammation; Leukotriene B4; Male; Muscle, Smooth, Vascular; Neutrophils; Platelet Activating Factor; Rats; Rats, Sprague-Dawley; Receptors, Leukocyte-Adhesion; Splanchnic Circulation

The importance of leukotrienes as mediators of inflammation and bronchoconstriction was examined with two recently described 5-lipoxygenase inhibitors, zileuton and A-78773. Preclinical evaluation of these two molecules indicates that they are potent, selective, direct, reversible inhibitors of 5-lipoxygenase with activity in a variety of purified cells and in more complex biological systems such as whole blood, lung fragments, and tracheal tissues. In various animals models of inflammation and allergy, the molecules inhibited edema, inflammatory cell influx, and bronchospasm. These observations are consistent with the recent clinical success of zileuton in treating asthma and inflammatory bowel disease. In all preclinical systems tested thus far, A-78773 is more potent and longer acting than zileuton, indicating that the molecule could be even more effective in the clinic than zileuton and that both molecules are useful tools in defining the role of leukotrienes in preclinical and clinical settings.

Topics: Animals; Bronchial Spasm; Guinea Pigs; Hydroxyurea; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Male; Rats

In the present study the inflammatory response was quantitatively evaluated during peripheral nerve regeneration. The fluid from silicone nerve regeneration chambers, inserted in rats, was collected during the early period of regeneration of transected sciatic nerves (6 h-7 d) and analysed with respect to inflammatory cells and mediators (leukotriene B4, LTB4, and interleukin-1 alpha, IL-1 alpha). Leucocytes were detected during the entire period (up to 7 d after implantation). The highest concentration was detected after 24 h. PMNG (polymorphonuclear granulocyte) was the predominant cell type in the chamber fluid during the initial 5d of regeneration. Analysis of the concentration of LTB4 demonstrated two peaks (at 24 h and 5 d). The IL-1 alpha concentration displayed an early and relatively smaller peak after 24 h and a second and much larger peak after 7 d, concomitant with an increase of the number of mononuclear cells.

Topics: Animals; Biocompatible Materials; Female; Inflammation; Interleukin-1; Leukotriene B4; Materials Testing; Models, Neurological; Nerve Regeneration; Rats; Rats, Sprague-Dawley; Sciatic Nerve; Silicones

1. The interaction between leukotriene B4 (LTB4) and its metabolite, 20-hydroxy LTB4 in the control of neutrophil emigration was examined in guinea-pig skin. 2. Leukotriene B4 (10-300 ng) elicited a dose-dependent increase in neutrophil infiltration (as measured by myeloperoxidase activity) 4 h after injection into guinea-pig skin. In contrast, 20-hydroxy LTB4 (30-1000 ng) displayed only weak inflammatory activity in this assay. 3. Although 20-hydroxy LTB4 had low agonist activity, this metabolite caused a potent dose-dependent inhibition of responses to LTB4 (100 ng), when administered systemically (ED50 = 1.3 micrograms kg-1, s.c.) without significantly affecting neutrophil infiltration in response to C5a (2 micrograms). Systemic administration of 20-carboxy LTB4 (10 micrograms) did not affect neutrophil accumulation in response to LTB4 or C5a. In addition, neither 15(S)-hydroxy 5(S)-HPETE(10 micrograms) nor lipoxin A4 (10 micrograms) inhibited responses to LTB4. 4. Addition of 20-hydroxy LTB4 (10(-11)-10(-8) M) to human blood prior to isolation of the neutrophils led to concentration-dependent decrease in the number of LTB4 receptors and decreased chemotactic responsiveness to LTB4 without affecting responses to C5a. Incubation of blood with 20-carboxy LTB4 (10(-8) M) did not reduce LTB4 receptor number of chemotactic responsiveness to LTB4. 5. These data indicate that although 20-hydroxy LTB4 is a weak agonist at LTB4 receptors, it can desensitize neutrophils to the effects of LTB4 via down-regulation of the high affinity receptor and thus provides evidence for a mechanism whereby inflammatory responses may be regulated.

Topics: Animals; Chemotaxis, Leukocyte; Guinea Pigs; In Vitro Techniques; Inflammation; Injections, Intradermal; Leukotriene B4; Male; Neutrophils; Peroxidase; Receptors, Leukotriene; Skin

Using an in vivo test system, the role of the beta 1 integrin very late activation antigen-4 (VLA-4) in eosinophil accumulation in allergic and nonallergic inflammatory reactions was investigated. Eosinophil infiltration and edema formation were measured as the local accumulation of intravenously injected 111In-labeled eosinophils and 125I-human serum albumin. The inflammatory reactions investigated were a passive cutaneous anaphylaxis (PCA) reaction and responses elicited by intradermal soluble inflammatory mediators (platelet-activating factor, leukotriene B4, C5a des Arg), arachidonic acid, and zymosan particles. The in vitro pretreatment of 111In-eosinophils with the anti-VLA-4 monoclonal antibody (mAb) HP1/2, which crossreacts with guinea pig eosinophils, suppressed eosinophil accumulation in all the inflammatory reactions investigated. Eosinophil accumulation was inhibited to the same extent when mAb HP1/2 was administered intravenously. It is interesting that HP1/2 had no effect on stimulated edema formation. These results suggest a role for VLA-4 in eosinophil accumulation in vivo and indicate a dissociation between the inflammatory events of eosinophil accumulation and edema formation.

Topics: Animals; Antibodies, Monoclonal; Edema; Eosinophils; Guinea Pigs; Inflammation; Leukotriene B4; Passive Cutaneous Anaphylaxis; Platelet Activating Factor; Receptors, Very Late Antigen; Zymosan

Repetitive motion injuries such as tendonitis are common sports injuries. However, few scientific studies are available on the effects of repetitive motion on mesenchymal cells and the presumed inflammatory response. This study used a new in vitro model to study the effects of repetitive motion. Human tendon fibroblasts were subcultured and plated on culture wells with flexible bottoms. The cells were repetitively stretched using a micro-processor-controlled pressure unit that causes a cyclic deformation of the flexible bottom. The wells were divided in the following groups: group I controls without repetitive motion, group IIA repetitive motion with 0.25 strain at 0.17 Hz (10 cycles.min-1), group IIB repetitive motion with 0.25 strain and 0.17 Hz in presence of 25 microM indomethacin, and group III repetitive motion with 0.25 strain at 1 Hz (60 cycles.min-1). After 3 h of stimulation the supernatant fluids were harvested and evaluated for prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and lactate dehydrogenase (LDH). The results showed significantly (P < 0.001) increased levels of PGE2 in groups IIA (46.9 +/- 4.7 pg.0.1 ml-1) and III (65.7 +/- 8.0 pg.0.1 ml-1). This represents a 1.3- and 1.8-fold increase, respectively, compared with the control group I (36.4 +/- 5.9 pg.0.1 ml-1). LTB4 was significantly (P < 0.001) elevated in the indomethacin-treated group IIB (45.0 +/- 11.0 pg.0.1 ml-1) compared with very low levels in all other groups. LDH was not significantly different in any of the experimental groups compared with the control group I. The results indicate that repetitive motion induces production of PGE2.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Analysis of Variance; Cells, Cultured; Cumulative Trauma Disorders; Dinoprostone; Fibroblasts; Humans; In Vitro Techniques; Indomethacin; Inflammation; L-Lactate Dehydrogenase; Leukotriene B4; Tendons

Aortic aneurysm repair produces inflammatory mediators, neutrophil activation, and remote organ injury. Reperfusion plasma from these patients produces microvascular injury in an ex vivo chemotactic model. This study investigates the mechanism of this injury. Vena caval blood was obtained before and 15 minutes after aortic clamp removal (n = 16) or at laparotomy (n = 10). Plasma or saline solution was introduced into unit dose chambers fixed atop dermabrasions on the back of depilated anesthetized rabbits. Animals were treated with intravenous saline solution (n = 4); made neutropenic with nitrogen mustard (n = 4); pretreated with the xanthine oxidase inhibitor allopurinol (n = 4); or cotreated intravenously with the free radical scavengers superoxide dismutase (SOD) and catalase (n = 4). Three hours later neutrophil counts (polymorphonuclear cells [PMN]/mm3) and activity (free radical production by flow cytometry), protein leakage, and inflammatory mediators (thromboxane [TX] and leukotriene B4 [LTB4]) were measured. In contrast to control plasma in untreated rabbits, reperfusion plasma produced TX and LTB4 generation (1090 +/- 105 and 794 +/- 91 pg/ml, respectively, p < 0.01), PMN accumulation (1636 +/- 210/mm3, p < 0.01) and activation (276 +/- 31 mean fluorescent units), and microvascular permeability (554 +/- 90 micrograms/ml, p < 0.01). Neutropenia (3 +/- 1 PMN/mm3) and cotreatment with SOD and catalase abolished these responses, whereas pretreatment with allopurinol did not. Human reperfusion plasma contains a soluble factor that stimulates free radical generation by rabbit neutrophils to produce a microvascular injury characterized by de novo TX production, neutrophil accumulation and activation, and increased microvascular permeability to protein.

Topics: Allopurinol; Animals; Aortic Aneurysm, Abdominal; Catalase; Cell Movement; Chemotaxis, Leukocyte; Dermabrasion; Humans; Inflammation; Leukocyte Count; Leukotriene B4; Male; Neutrophils; Proteins; Rabbits; Reperfusion Injury; Skin; Superoxide Dismutase; Thromboxane B2

We examined the effect of phorbol myristate acetate on cultured bovine aortic endothelial cells to determine the role of endothelial cells in neutrophil-endothelial cell adhesive interactions. Confluent endothelial cells were preincubated with phorbol myristate acetate and other inflammatory signals including N-formylmethionyl-leucyl-phenylalanine (f-Met-Leu-Phe), the ionophore A23187, and thrombin; washed extensively; and incubated with 51Cr-labeled neutrophils. Preincubation of endothelium with A23187, phorbol ester, or thrombin increased adherence of neutrophils by 3.1-, 5.7-, and 3.7-fold over baseline. In contrast, f-Met-Leu-Phe preincubation failed to increase adhesion over baseline. Supernatants from endothelium preincubated with phorbol failed to augment adherence of untreated endothelial cells. Preincubation of endothelium with lipoxygenase inhibitors nordihydroguaiaretic acid (50 microM), 5,8,11,14-eicosatetraenoic acid (50 microM), and BW755C (50 microM) inhibited the effect of phorbol preincubation of endothelium significantly by 55, 27, and 22%, respectively. In contrast, inhibitors of cyclooxygenase and thromboxane synthase or thromboxane receptor antagonists had no effect on phorbol-induced adhesion. Specific desensitization of neutrophil adhesion to phorbol-treated endothelium could be demonstrated by prior exposure of neutrophils to low concentrations of leukotriene B4 (3.8 x 10(-10) M). Endothelium preincubated with phorbol but not f-Met-Leu-Phe or thrombin produced several fatty acid peaks at 280 nm, one of which comigrated with authentic leukotriene B4 (LTB4). This peak, isolated and purified, increased endothelial cell adherence in a temporal fashion in the same way as LTB4 and was demonstrated to be LTB4 by ultraviolet spectroscopy, high-performance liquid chromatography, and mass spectroscopy. These data demonstrate that endothelial cell-derived lipoxygenase metabolites, in particular LTB4, are involved, in part, in the acute regulation of neutrophil adhesion to endothelium induced by inflammatory signals such as phorbol ester.

Topics: Animals; Arachidonic Acid; Cattle; Cell Adhesion; Cells, Cultured; Endothelium, Vascular; Humans; Inflammation; Leukotriene B4; Lipoxygenase; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Tetradecanoylphorbol Acetate; Thrombin

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Benzoates; Calcium; Humans; Inflammation; Leukotriene B4; Mice; Molecular Structure; Neutrophils; Pyridines; Receptors, Leukotriene B4

To investigate the relative irritant potencies of inhaled aldehydes, guinea pigs were exposed to formaldehyde or acrolein and specific total pulmonary resistance and bronchial reactivity to intravenous acetylcholine were assessed. The mechanisms associated with these responses were investigated by analyzing morphologic and biochemical changes in airway epithelial cells after in vivo and in vitro exposures. Immediately after exposure to formaldehyde or acrolein, specific resistance increased transiently and returned to control values within 30 to 60 minutes. Bronchial hyperreactivity, assessed by the acetylcholine dose necessary to double resistance, increased and became maximal two to six hours after exposure to at least 9 parts per million2 (ppm) formaldehyde or at least 1 ppm acrolein for two hours. The effect of exposure to 3 ppm formaldehyde for two hours was less than the effect of exposure to 1 ppm formaldehyde for eight hours; thus, extended exposures produced a disproportionate heightening of bronchial reactivity. Bronchial hyperreactivity often persisted for longer than 24 hours. Increases in three bronchoconstrictive eicosanoids, prostaglandin F2 alpha, thromboxane B2, and leukotriene C4, occurred immediately after exposure, whereas an influx of neutrophils into lavage fluid occurred 24 hours later. Histological examination of the tracheal epithelium and lamina propria also demonstrated a lack of inflammatory cell infiltration. Treatment with leukotriene synthesis inhibitors and receptor antagonists inhibited acrolein-induced hyperreactivity, supporting a causal role for these compounds in this response. Acrolein also stimulated eicosanoid release from bovine epithelial cells in culture. However, the profile of metabolites formed differed from that found in lavage fluid after in vivo exposure. Similarly, human airway epithelial cells did not produce cysteinyl leukotriene or thromboxane B2. However, cysteinyl leukotrienes were mitogenic for human airway epithelial cells in a concentration-dependent manner and exhibited a structure-activity relationship; leukotriene C4 was more potent than its sequential metabolites D4 and E4. The potency of leukotriene C4 was striking, stimulating colony-forming efficiency in concentrations as low as 0.01 pM. Together, these findings suggest that environmentally relevant concentrations of aldehydes can induce bronchial hyperreactivity in guinea pigs through a mechanism involving injury to cells present in the air

Topics: Acetylcholine; Acrolein; Air Pollutants; Airway Resistance; Animals; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Epithelium; Epoprostenol; Formaldehyde; Guinea Pigs; Hyperplasia; Inflammation; Leukocyte Count; Leukotriene B4; Lipoxygenase Inhibitors; Neutrophils; Phenothiazines; Phenylbutyrates; Prostaglandins F; SRS-A; Thromboxane B2; Time Factors

Sipid mediators of inflammation have been implicated in the pathogenesis of Pseudomonas aeruginosa (PA) related pulmonary damage in patients with cystic fibrosis. We studied the role of these mediators in a rat model of PA endobronchitis using essential fatty acid deficient (EFAD) animals. Whole blood from EFAD animals produced significantly less leukotriene B4 (LTB4) and hydroxyheptadecatrienoic acid when stimulated ex vivo than did whole blood from control animals (p less than 0.005). Similarly, lung lavage fluid from EFAD animals infected with PA contained less LTB4 and thromboxane B2 (TXB2) than that from control animals. Despite these differences, cellular infiltration of airways in response to PA infection was virtually identical in animals from the regular diet and the EFAD groups. Both EFAD and control animals had a significant increase in white blood cells (WBC) in lung lavage fluid at 1, 3 and 6 days following infection with PA when compared to animals receiving sterile beads. Localized areas of consolidation and nodularity were grossly evident in the lungs of all PA infected animals irrespective of their ability to generate the lipid inflammatory mediators. Microscopic examination of lung sections demonstrated similar changes in all infected animals. We conclude that LTB4 and TXB2 production occurs early in the course of PA pulmonary infection in rats. This early rise in lipid mediators is temporally associated with an influx of WBC into the airways. However, attenuation of eicosanoid production by use of an EFAD diet does not lead to a reduction in the inflammatory response to PA infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Bronchoalveolar Lavage Fluid; Dietary Fats, Unsaturated; Eicosanoids; Fatty Acids, Essential; Fatty Acids, Unsaturated; Inflammation; Leukotriene B4; Male; Pneumonia; Pseudomonas Infections; Rats; Rats, Inbred Strains; Thromboxane B2

A video system was used to investigate the inhibitory effect(s) of the glucocorticoid dexamethasone (DEX) on polymorphonuclear leukocyte (PMN) extravasation in the microcirculation of hamster cheek pouch. DEX was given intraperitoneally at 0.1 or 0.3 mg/kg body weight 2 h before induction of extravasation by topical application of leukotriene B4 (LTB4) or formyl-methionyl-leucyl-phenylalanine (fMLP) on the microvasculature. The number, time course, and behavior of PMNs were examined in the following five steps of extravasation: (1) rolling on the venular endothelium, (2) adhesion on the endothelium, (3) passage between the endothelial cells, (4) staying in the venular wall, and (5) migration from the venular wall into the interstitial space. In either the presence or absence of DEX, topical application of LTB4 (15 pmol/50 microliters) or fMLP (10 nmol/50 microliters) caused an increase in the number of PMNs that adhered to the venules. Thus, DEX did not inhibit the adhesion of PMNs on the endothelial cells. The adhered PMNs induced by these chemoattractants became gradually smaller, finally disappearing in the vascular lumen, as observed on the monitor screen. The whole process took about 10 min. This passage of PMNs between the endothelial cells was also not inhibited by DEX, as over 90% of the adhered PMNs passed through the endothelial cells and advanced to the next step of extravasation in the presence or absence of DEX. When these chemoattractants were applied to DEX-untreated animals, the PMNs that passed through the endothelial cells stayed for about 30 min in the venular wall. Thereafter, PMNs migrated into the interstitial space. The numbers of PMNs in the interstitial space were counted at 30, 60, and 90 min after the application of chemoattractants. In the DEX-untreated animals, PMNs in the interstitial space started to appear by 30 min, and thereafter the number further increased. However, in the DEX-treated animals, the number of PMNs at 60 and 90 min was significantly suppressed. Since DEX may inhibit the synthesis and/or release of a proteinase(s) in the PMN granules, which would normally degrade the basement membrane, this inhibition may be due to the inability of PMNs to penetrate the basement membrane.

Topics: Animals; Cell Adhesion; Cell Movement; Cheek; Cricetinae; Dexamethasone; Endothelium, Vascular; Inflammation; Leukotriene B4; Microcirculation; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils

ONO-4057(5-[2-(2-Carboxyethyl)-3-[6-(4-methoxyphenyl)-5E- hexenyl]oxyphenoxy]valeric acid), an orally active leukotriene B4(LTB4) antagonist, displaced the binding of [3H] LTB4 to the LTB4 receptor in human neutrophil (Ki = 3.7 +/- 0.9 nM). ONO-4057 inhibited the LTB4-induced rise in cytosolic free calcium (the concentration causing 50% inhibition (IC50) = 0.7 +/- 0.3 microM) and inhibited human neutrophil aggregation, chemotaxis or degranulation induced by LTB4 (IC50 = 3.0 +/- 0.1, 0.9 +/- 0.1 and 1.6 +/- 0.1 microM) without showing any agonist activity at concentration up to 30 microM. ONO-4057 did not inhibit fMLP or C5a-induced neutrophil activation at concentrations up to 30 microM. In the in vivo study, ONO-4057 given orally, prevented LTB4-induced transient neutropenia or intradermal neutrophil migration in guinea pig (the dose causing 50% efficacy (ED50) = 25.6mg/kg or 5.3mg/kg). Furthermore, ONO-4057 given topically, suppressed phorbol-12-myristate-13-acetate (PMA)-induced neutrophil infiltration in guinea pig ear (the effective dose = 1 mg/ear). These results indicate that ONO-4057 is a selective and orally active LTB4 antagonist and may be a potential candidate for the treatment of various inflammatory diseases.

Topics: Animals; Calcium; Cell Aggregation; Chemotaxis, Leukocyte; Complement C5a; Cytoplasmic Granules; Guinea Pigs; Humans; Inflammation; Leukotriene B4; Male; N-Formylmethionine Leucyl-Phenylalanine; Neutropenia; Neutrophils; Phenylpropionates; Receptors, Immunologic; Receptors, Leukotriene B4; Tetradecanoylphorbol Acetate

Administration of amiodarone, although often lifesaving, is associated with pulmonary side effects. Patients with amiodarone pulmonary toxicity can present with either a chronic disorder that suggests pulmonary fibrosis or a more acute process. Mechanisms of acute pulmonary injury resulting from amiodarone are unclear. Previous studies have demonstrated that the drug is preferentially concentrated in alveolar macrophages. In the present study, the authors examined whether in vitro exposure to amiodarone resulted in alteration of rat alveolar macrophage superoxide, leukotriene B4, or fibronectin release. In addition, the authors assessed whether macrophages were ultrastructurally altered by in vitro amiodarone exposure. Twenty four hour exposure to therapeutic tissue concentrations of amiodarone resulted in enhancement of phorbol myristate acetate-stimulated macrophage superoxide release. In addition, 48 hours exposure to amiodarone caused a dose-dependent inhibition of spontaneous fibronectin release by macrophages. Macrophages exposed to 48 hours of 10 micrograms/ml amiodarone were ultrastructurally abnormal, containing lamellar inclusions and demonstrating a large degree of vacuolization. The authors concluded that alveolar macrophages are very sensitive to therapeutic tissue concentrations of amiodarone. Alteration of macrophage mediator release by amiodarone may be one mechanism for lung damage induced by the drug.

Topics: Amiodarone; Animals; Cell Adhesion; Fibronectins; In Vitro Techniques; Inflammation; Leukotriene B4; Macrophages, Alveolar; Male; Microscopy, Electron; Rats; Superoxides

Human monocytes released superoxide anion, prostaglandin E2, leukotriene B4, IL-1, and TNF when exposed to plastic surfaces coated with murine anti-CD3 monoclonal antibody, OKT 3. Stimulation of mediator release by OKT 3 was dependent on the amount of antibody immobilized onto wells of plastic tissue culture plates. Soluble antibody or antibody adsorbed to monocytes and reacted with an aggregating ("cross-linking") second antibody failed to induce mediator release. Monocytes "armed" with OKT 3 formed rosettes with T cells in a fashion indistinguishable from that seen between monocytes and T cells sensitized with OKT 3. Monocytes with adsorbed OKT 3 antibodies released IL-1 beta and TNF-alpha when exposed to unsensitized T cells, although increased superoxide release could not be detected. OKT 4a, a murine IgG2a antibody that reacts with a different T cell epitope (CD4), failed to induce cytokine release from monocytes when cross-linked by T cells or a CD4+ T cell line, even in the presence of IL-2 or IFN-gamma. These data indicate that certain antibodies bound to Fc receptors (FcR) of monocytes may trigger monocyte function when reacting with cells bearing the appropriate target antigens. FcR-mediated signaling resulting in mediator release may be involved in initiating or regulating the immune response. Furthermore, systemically administered monoclonal antibodies may induce inflammatory responses and their attendant symptomatologies via their interaction with FcR-bearing inflammatory cells.

Topics: Adsorption; Antibodies, Monoclonal; CD3 Complex; Dinoprostone; Humans; Immunoglobulin G; Inflammation; Interleukin-1; Leukotriene B4; Monocytes; Receptors, Fc; Rosette Formation; Superoxides; T-Lymphocytes; Tumor Necrosis Factor-alpha

1. This paper describes the pre-clinical pharmacology of ICI D2138, a potent orally-active non-redox inhibitor of 5-lipoxygenase which is undergoing clinical evaluation. 2. ICI D2138 potently inhibited leukotriene synthesis in murine peritoneal macrophages (IC50 = 3 nM) and human blood (IC50 = 20 nM). In human and dog blood, ICI D2138 did not inhibit thromboxane B2 synthesis at a concentration of 500 microM, thus the selectivity ratio (cyclo-oxygenase: 5-lipoxygenase) was greater than 20,000. In contrast, zileuton (a 5-lipoxygenase inhibitor also undergoing clinical evaluation) exhibited a selectivity ratio of 15-100. 3. ICI D2138 potently and dose-dependently inhibited ex vivo leukotriene B4 (LTB4) synthesis by rat blood with ED50 values of 0.9, 4.0 and 80.0 mg kg-1 p.o. at 3, 10 and 20 h respectively after dosing. Similar activity was observed for inhibition of LTB4 production in a zymosan-inflamed rat air pouch model. Zileuton produced ED50 values of 5 and 20 mg kg-1 at 3 and 10 h respectively. 4. Oral administration of 1, 3 or 10 mg kg-1 ICI D2138 to dogs produced maximal inhibition of ex vivo LTB4 synthesis by blood for 5, 9 and 31 h respectively. A dose of 5 mg kg-1 p.o. of zileuton caused maximal inhibition of LTB4 for 24 h. 5. Oral administration of 10 mg kg-1 ICI D2138 caused total inhibition of LTB4 production in zymosan-inflamed rabbit knee joint. 6. Topical administration of ICI D2138 to rabbit skin caused a dose-related inhibition of arachidonic acid-induced plasma extravasation with an ID30 of 1.08 nmol per site. Zileuton was approximately 40 times less potent.7. Oral anti-inflammatory activity was assessed in an arachidonic acid-induced mouse ear oedema model in animals treated with indomethacin to block pro-inflammatory prostanoids. ICI D2138, given orally, caused dose-dependent inhibition of oedema with an approximate ID50 of 1.8 mg kg'. Zileuton was approximately 10 times less potent.8. ICI D2138 caused a dose-dependent inhibition of antigen-induced broncho-constriction in guineapigs with an approximate ID50 of 0.1 mg kg-', i.v. Zileuton was approximately 10 times less potent.9. In view of the pharmacological profile described here, ICI D2138 has the potential to provide improved clinical efficacy compared to existing lipoxygenase inhibitors such as zileuton.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Bronchoconstriction; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Guinea Pigs; Hydroxyurea; Inflammation; Knee Joint; Leukotriene B4; Lipoxygenase Inhibitors; Macrophages; Male; Mice; Oxidation-Reduction; Pyrans; Quinolones; Rabbits; Rats; Thromboxane B2

The present work was designed to further study the mechanism of the anti-inflammatory action of musk from the viewpoint of arachidonic acid (AA) metabolism: 1) effect on AA release; 2) action on leukotriene B4 (LTB4) and 5-HETE biosyntheses. Leukocytes obtained from rat inflammatory exudate by i.p. injection of 1% carrageenan were labelled with 14C-AA at 37 degrees C for 2 h. The 14C-AA labelled cells were incubated with the water soluble fraction of musk (MWF) and stimulated with calcium ionophore A23187 to release AA. The radioactivity released from the labelled leukocytes was determined as a criterion of AA release. In order to observe the influence of musk on the biosyntheses of LTB4 and 5-HETE, leukocytes were incubated with MWF and AA, and then stimulated with A23187. The LTB4 and 5-HETE produced were determined by RP-HPLC. The results showed that AA release decreased to 50-70% of the control at MWF concentration of 6.25-37.5 micrograms/ml. The biosyntheses of LTB4 and 5-HETE were not affected. However, AA release increased to 1.5-fold at the MWF concentration of 400 micrograms/ml. At the same time, biosyntheses of LTB4 and 5-HETE decreased by 66.7 and 90%, respectively, as compared with controls. This result indicates that MWF not only inhibited phospholipase A2 (PLA2) activity, but also prevented AA peroxidation and inhibited LTB4 biosynthesis. These results suggest that inhibition of the AA metabolic pathway may play a major role in the mechanism of the anti-inflammatory action of musk.

Topics: Animals; Arachidonic Acid; Carrageenan; Exudates and Transudates; Fatty Acids, Monounsaturated; Hydroxyeicosatetraenoic Acids; Inflammation; Leukocytes; Leukotriene B4; Rats

Topics: Calcimycin; Dinoprostone; HEPES; Humans; Inflammation; Leukotriene B4; Luminescent Measurements; Neutrophils; Psoriasis; Reference Values; Skin Diseases; Taurine

The 5-lipoxygenase inhibitors WY-50,295 tromethamine, A-64,077, L-663,536 and ICI-207,968 were compared in a reverse passive Arthus reaction-induced pleurisy model of eicosanoid biosynthesis in the rat. When a 1 h pretreatment schedule was employed, all four inhibitors equivalently blocked leukotriene B4 (LTB4) production with ED50 values of 2.0-2.9 mg/kg p.o. Conversely, WY-50,295 tromethamine (225 mg/kg p.o.) and L-663,536 (100 mg/kg p.o.) did not significantly alter thromboxane B2 (TxB2) levels, whereas A-64,077 (50 mg/kg p.o.) and ICI-207,968 (100 mg/kg p.o.) significantly reduced TxB2 by 50 and 72%, respectively. When 3 and 18 h pretreatment schedules were employed, WY-50,295 tromethamine demonstrated a longer duration of action than the other 5-lipoxygenase inhibitors with ED50 values of 1.7 and 6.3 mg/kg p.o., respectively. At doses of 50 and 100 mg/kg p.o., all drugs tested significantly inhibited inflammatory cell influx by 15-27%, albeit in a non-dose-related manner. However, only A-64,077 significantly lowered fluid extravasation by 35%, presumably due to inhibition of cyclooxygenase product formation. These results demonstrate that in this rat reverse passive Arthus pleurisy model, WY-50,295 tromethamine potently and selectively inhibits 5-lipoxygenase in vivo, and possesses a longer duration of action than the other 5-lipoxygenase inhibitors employed.

Topics: Animals; Arthus Reaction; Biomarkers; Dose-Response Relationship, Drug; Eicosanoids; Exudates and Transudates; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Pleurisy; Radioimmunoassay; Rats

IL-8 has been characterized primarily as a polymorphonuclear leukocyte (PMN) chemoattractant and proinflammatory mediator. Recently, we have reported that [Ala-IL-8]77 is secreted by activated cultured human endothelial cells and can function as a potent inhibitor of PMN adhesion to these monolayers. The pathophysiologic relevance of this in vitro observation was examined by determining the effects of intravascular or extravascular administration of IL-8 on PMN emigration at sites of acute inflammation in the skin of NZW rabbits. An i.v. bolus of [Ala-IL-8]77 (12 micrograms/kg) produced a marked and selective reduction of circulating PMN within 3 min, which returned toward preinjection levels within 30 min, and subsequently exceeded this level. A similar response was observed for circulating radiolabeled PMN, and gamma-scintigraphy determined that the lungs were the primary site of leukosequestration. During the 30- to 150-min interval after i.v. infusion of [Ala-IL-8]77, PMN emigration into acute inflammatory sites, elicited by various chemoattractants or cytokines, was significantly reduced, as judged histologically and quantitated with 51Cr-labeled PMN and myeloperoxidase measurements. Intravenous administration of [Ser-IL-8]72 yielded similar results. This inhibitory effect of i.v. IL-8 was transient and reinducible and did not reflect a suppression of the responsiveness of circulating PMN to chemoattractants. Intradermal injections of [Ala-IL-8]77 or [Ser-IL-8]72 induced dose-dependent PMN accumulation, which also was significantly reduced by i.v. administration of either form of IL-8. These results indicate that i.v. IL-8 can function as a PMN-directed leukocyte adhesion inhibitor and suggest that local secretion of IL-8 by activated endothelium may differentially modulate leukocyte-endothelial interactions at sites of acute inflammation.

Topics: Animals; Cell Movement; Chemotactic Factors; Complement C5a; Dose-Response Relationship, Drug; Inflammation; Injections, Intravenous; Interleukin-1; Interleukin-8; Leukotriene B4; Male; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Rabbits; Time Factors; Tissue Distribution

A group of flavonoids isolated from medicinal plants and which are selective inhibitors of lipoxygenase activity in vitro: sideritoflavone, cirsiliol, hypolaetin-8-O-beta-D-glucoside, hypolaetin, oroxindin, quercetagetin-7-O-beta-D-glucoside, gossypin, hibifolin and gossypetin, besides leucocyanidol, have been studied for their effects on acute responses induced by carrageenin in mice. The oral administration of flavonoids to mice inhibited dose-dependently the development of paw oedema at 1, 3 and 5 h after carrageenin injection. A similar administration of flavonoids induced a dose-dependent inhibition of leukocyte accumulation in inflammatory exudates following intraperitoneal injection of carrageenin into mice. Some of the flavonoids exhibited a potency against leukocyte infiltration similar to that seen for inhibition of carrageenin oedema at 3 h of induction. In agreement with data reported in rats, indomethacin was much more effective on inhibition of prostaglandin E2 (PGE2) formation than on leukocyte infiltration in mice. The selectivity of flavonoids towards lipoxygenase is not retained in vivo since they behave as dual inhibitors of PGE2 and leukotriene B4 (LTB4) formation in peritoneal exudates. Our data support the inhibition of arachidonic acid metabolism as one of the mechanisms by which flavonoids exert their anti-inflammatory effects.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Arachidonic Acids; Carrageenan; Dinoprostone; Edema; Flavonoids; Inflammation; Leukocytes; Leukotriene B4; Male; Mice; Peritonitis; Plants, Medicinal

TNF is a potent cytokine which can induce many of the pathological changes associated with inflammatory disease. In vitro studies have demonstrated that 5-lipoxygenase products promote the production of TNF by activated macrophages, suggesting that 5-lipoxygenase inhibitors may have therapeutic utility for the treatment of inflammatory conditions. A rat airpouch model of inflammation has been used to investigate the relationship between eicosanoid generation and TNF production in vivo. Injection of zymosan into the airpouch caused a time-dependent stimulation of TNF production which preceded leukotriene generation by at least 30 minutes. Injection of LPS into the airpouch also stimulated TNF production but not leukotriene generation. The selective 5-lipoxygenase inhibitors, ICI207968, A64077 and BWA4C, and the 5-lipoxygenase translocation inhibitor MK886, decreased leukotriene generation but enhanced TNF production. Taken together, these results do not support a role for 5-lipoxygenase products in the regulation of TNF production in vivo.

Topics: Animals; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Indomethacin; Inflammation; Kinetics; Leukotriene B4; Lipopolysaccharides; Lipoxygenase Inhibitors; Male; Rats; Rats, Inbred Strains; SRS-A; Tumor Necrosis Factor-alpha; Zymosan

Intraperitoneal and intra-articular (knee joint) injection of zymosan in the rat caused two phases of increased vascular permeability, a rapid increase (0.25-0.5 h) and a secondary increase (2-3 h) which was temporally associated with the onset of leukocyte infiltration. Intraperitoneal injection of zymosan led to a single peak of eicosanoid production (LTB4, C4, D4, E4 and 6-oxo-PGF1 alpha) which was maximal at 0.125-0.25 h. Intra-articular injection led to an initial peak of LTB4 production (maximal at 0.25 h) and a secondary peak of LTB4 and PGE2 production (maximal at 3 h). Oral administration of the 5-lipoxygenase (5-LO) inhibitors phenidone, BW A4C (N-hydroxy-N-[3-(3-phenoxyphenyl)-2-propenyl] acetamide), A63162 (N-hydroxy-N-[1-(4-(phenylmethoxy) phenyl)ethyl] acetamide and ICI 207 968 (2-[3-pyridylmethyl]-indazolinone inhibited LTB4 production in A23187 stimulation blood ex vivo. The glucocorticosteroid dexamethasone had no effect in this model. The initial phase of increased vascular permeability in the peritoneal cavity and LTB4 production was dose dependently inhibited by the 5-LO inhibitors phenidone, BW A4C, A63162, and ICI 207 968 but not by dexamethasone or colchicine. The initial phase of increased permeability in the joint was unaffected by phenidone, BW A4C, dexamethasone or colchicine. However the latter two drugs inhibited the later phase of increased permeability and leukocyte infiltration in the joint and peritoneal cavity. These results demonstrate that zymosan induces eicosanoid production in vivo but the relative importance of these mediators varies depending on the inflammatory site.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arthritis; Benzeneacetamides; Calcimycin; Colchicine; Dexamethasone; Dinoprostone; Disease Models, Animal; Hydroxamic Acids; Inflammation; Kinetics; Knee Joint; Leukocytes; Leukotriene B4; Leukotrienes; Lipoxygenase Inhibitors; Male; Peritonitis; Pyrazoles; Rats; Zymosan

It is currently thought that pulmonary eosinophils play a proinflammatory role in bronchial asthma. Leukotriene B4 (LTB4) is being considered as an important mediator in regulating eosinophil function because of its potent activities in inducing leukocyte chemotaxis, chemokinesis, degranulation, and aggregation. Because the LTB4 receptor has not been characterized in eosinophils, we report in this study the presence of a functional high affinity receptor for LTB4 on guinea pig (GP) eosinophils. Scatchard analysis of saturation binding studies yielded a Kd of 1.4 +/- 0.2 nM (mean +/- SEM, n = 3) and a Bmax of 1.6 +/- 0.4 pmol/mg of protein for LTB4 in GP eosinophil membranes. A linear Scatchard plot was obtained, suggesting that GP eosinophil membranes expressed only a single high affinity LTB4 receptor population. Saturation binding studies in whole cells also yielded a linear Scatchard plot, with a Kd of 2.8 +/- 0.96 nM (mean +/- SEM, n = 4) and a Bmax of 4 x 10(4) +/- 6 x 10(3) receptors/cell. Competitive binding studies using several compounds with structures similar to that of LTB4 showed that these agents bound to the receptor in the following descending order of affinity (Ki, nM): LTB4 (0.96) less than TB3 (1.0) greater than 20-hydroxy-LTB4 (3.5) greater than 12(R)-hydroxy-5,8,14-cis,10-trans-eicosatetraenoic acid (20) greater than 12(S)-hydroxy-5,8,14-cis,10-trans-eicosatetraenoic acid (231) greater than 20-carboxy-LTB4 (350) greater than 5(S),12(S)-dihydroxy-6,10-trans,8,14-cis-eicosatetraenoic acid (541). This rank order of potency in binding affinity correlates closely with the ability of these compounds to induce both chemotaxis and superoxide anion generation. Analysis of the structure-activity relationship suggests that the 12R-hydroxyl group and a cis double bond at the C-6 position are important for optimal agonist binding to the LTB4 receptor present in GP eosinophil membranes. The results suggest that LTB4 may be an important chemoattractant for eosinophils in GP and may induce the release of reactive oxygen species from this cell.

Topics: Animals; Binding, Competitive; Cell Membrane; Chemotaxis, Leukocyte; Eosinophils; Guinea Pigs; Inflammation; Kinetics; Leukotriene B4; Receptors, Immunologic; Receptors, Leukotriene B4; Respiratory Burst; Structure-Activity Relationship; Superoxides

Inflammatory exudates obtained in rats after subcutaneous implantation of carrageenin-soaked sponges were found to contain relatively large amounts of 15-hydroxy-5,8,11, 13-eicosatetraenoic acid (15-HETE) and smaller amounts of cysteinyl-leukotrienes (LT) in addition to LTB4, thromboxane (TX) B2 and prostaglandin (PG)E2. Concentrations of 15-HETE and cysteinyl-LT were high 5 hours after sponge implantation and decreased significantly within 24 hours. This time-course, which is similar to that of TXB2, but differs from that of PGE2, suggests migrating leukocytes as a major source of 15-HETE and cysteinyl-LT. Aspirin, sodium salicylate, dipyrone (100 mg/kg each) and indomethacin (2 and 20 mg/kg) decrease the concentrations of cyclooxygenase products of arachidonate metabolism, but did not significantly affect levels of 15-HETE. Cysteinyl-LT were increased by 20 mg/kg indomethacin, but remained unaffected by 2 mg/kg indomethacin and by the other non-steroidal anti-inflammatory drugs (NSAID) tested. 15-HETE and cysteinyl-LT could play a mediator role in inflammation. In addition, they could modulate the release and effects of other inflammatory mediators.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Dinoprostone; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Radioimmunoassay; Rats; Rats, Inbred Strains; SRS-A; Thromboxane B2

Inhalation of aerosols of ovalbumin in sensitized guinea pigs produced a marked, bronchoalveolar eosinophilia 24 hr after challenge. The lung eosinophilia was not prevented by the cyclooxygenase inhibitors, indomethacin or PAF antagonists (WEB-2086 and L-652731) but was inhibited by methylprednisolone, the 5-LO inhibitor, U-66858 and a series of structural analogs of LTB4, U-75302, U-77692, U-75485 and U-78489. The effectiveness of LTB4 antagonists but not PAF antagonists in vivo was consistent with in vitro studies in which LTB4 was shown to be far more chemotactic than PAF for guinea pig eosinophils. LTB4 elicited maximal directional migration of guinea pig eosinophils at concentrations from 10(-7) M to 10(-9) M while PAF showed no effect over the same concentration range. The structural analogs of LTB4 were shown to inhibit LTB4 induced chemotaxis of guinea pig eosinophils and produced a dose-related inhibition of binding of LTB4 to guinea pig eosinophil membranes. To add further proof to the hypothesis that LTB4 contributed to the antigen-induced lung eosinophilia we attempted to measure LTB4 release into BAL fluid immediately after and at various time points up to 24 hr after antigen inhalation. However, using a sensitive radioimmunoassay (detection limit 10 pg/ml) very low levels of LTB4 (24.9-67.9 pg/ml) or its metabolite, 20-OH LTB4 (24.9-98.2 pg/ml) were detected in BAL fluid and these levels did not increase significantly following antigen provocation. Inhalation of LTB4 aerosols in unsensitized Brown-Norway rats or inhalation of aerosols of ovalbumin in sensitized Brown-Norway rats also produced a marked "late-phase" eosinophil-rich influx of inflammatory cells into the lungs. The lung eosinophilia in the rat was prevented by two structurally unrelated leukotriene B4 (LTB4) antagonists, U-75302 and Ly255283. These data implicate LTB4 as a mediator of allergen-induced bronchopulmonary eosinophilia. Leukotriene B4 antagonists may provide leads for the development of compounds which inhibit the chronic airway inflammation associated with asthma in man.

Topics: Aerosols; Animals; Chemotaxis, Leukocyte; Eosinophils; Guinea Pigs; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Male; Ovalbumin; Rats; Rats, Inbred BN; Structure-Activity Relationship

The inflammatory reaction elicited after implantation of non-biologic materials was studied by analysis of the exudate in pure titanium or polytetrafluorethylene chambers 1-9 d after insertion in the abdominal wall of the rat. In chambers made of pure titanium, the number of leucocytes increased about twofold from 1.8 x 10(6)/ml to 4.1 x 10(6)/ml between 24 h and 6 d, whereas a larger increase from 2.1 x 10(6)/ml to 8.3 x 10(6)/ml was observed in the polytetrafluorethylene chambers. Irrespective of implant material, polymorphonuclear granulocytes constituted the vast majority of leucocytes (greater than 81%). After 24 h the leukotriene B4 content was slightly higher in polytetrafluorethylene chambers than in titanium chambers. In contrast to the titanium chambers, a marked increase in leukotriene B4 levels was detected in polytetrafluorethylene chambers 6 d after insertion, whereas the greatest amount of leukotriene B4 in titanium chambers was measured at 9 d. Interleukin 1 was only detected in both types of chambers after 6 d. The present study, together with previous findings, shows that the materials used in this study elicit different degrees of inflammatory reactions in the chamber exudate. Since the number of leucocytes in the exudate retrieved from the chambers correlated well with the leukotriene B4 levels, it is suggested that leukotriene B4, but not interleukin 1, may be an important mediator for polymorphonuclear granulocyte migration into the implant-tissue interface.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Abdominal Muscles; Animals; Inflammation; Interleukin-1; Leukocytes; Leukotriene B4; Male; Polytetrafluoroethylene; Prostheses and Implants; Rats; Rats, Inbred Strains; Time Factors; Titanium

Leukotriene induction of the fluid and cellular phases of the inflammatory response in the mouse was evaluated. Intraperitoneal injection of leukotriene C4 (LTC4 250 ng) led to dye extravasation but not polymorphonuclear leukocyte (PMN) infiltration, whereas injection of leukotriene B4 (LTB4 250 ng), led to PMN infiltration but not dye extravasation. The injection of both leukotrienes did not result in synergy. LTC4 did not appear to induce significant release or formation of chemotactic mediators, but the dye extravasation induced by LTC4 was inhibited by the vasoactive amine antagonist cyproheptadine and not by the eicosanoid inhibitors phenidone or naproxen. The response was markedly inhibited by the cytokine and eicosanoid inhibitors SK&F 86002 and SK&F 104493. PMN infiltration induced by LTB4 was not inhibited by SK&F 86002 or phenidone but was abrogated by colchicine treatment. LTB4 in this model did not appear to cause release or formation of vasoactive mediators. These leukotrienes appeared to be independent, complementary, and sufficient to mount a complete inflammatory response in the mouse.

Topics: Animals; Ascites; Capillary Permeability; Chemotaxis, Leukocyte; Colchicine; Drug Interactions; Imidazoles; Inflammation; Injections, Intraperitoneal; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Neutrophils; Peritonitis; Pyrazoles; SRS-A; Thiazoles

Previous in vitro studies have shown that adenosine (ADO)-induced inhibition of granulocyte function is near maximal at the sub-micromolar concentrations that would be anticipated in normal tissues. If this mechanism is operative in vivo, then antagonizing ADO receptors should potentiate granulocyte-mediated inflammatory responses. To unmask the putative inhibition, the antagonist, 8-phenyl theophylline (8pTHEO), was continuously suffused over the hamster cheek pouch microcirculation, which was observed with intravital bright field and fluorescence microscopy. As an index of inflammation, macromolecular permeability was measured by determining extravasation of fluorescein isothiocyanate-labelled dextran (MW 150,000). In addition, tissue specimens were fixed and stained with hematoxylin and eosin for histological quantification of intravascular and extravascular granulocytes. The tissue was challenged with a 10-40 min topical application of leukotriene B4 (LTB4, 1.1-4nM) or histamine (0.5 or 10 microM) with and without 8pTHEO, at a concentration (8 microM) that attenuated vasodilation evoked by exogenous ADO. These two inflammatory stimuli were chosen because LTB4 evokes a granulocyte-dependent response in the cheek pouch, while histamine evokes a granulocyte-independent response. 8pTHEO potentiated the dose-related increase caused by LTB4 but had no effect on permeability in baseline conditions or on the response evoked by histamine. In baseline conditions, there were fewer than 500 intravascular granulocytes/mm2 microvessel surface area and fewer than 3000 extravascular granulocytes/cm2 tissue surface area. After LTB4 challenge, there was a 3-4 fold increase in the numbers of extra- and intra-vascular granulocytes compared to baseline, but no dose-related relationship could be detected over the concentration range 1.1-4 nM. With 8pTHEO + 1.1 nM LTB4, the granulocyte accumulation was similar to that with LTB4 alone, but there were significantly more intravascular and extravascular granulocytes in the 8pTHEO after 2.5-4 nM LTB4. In context with previous studies, these results suggest that endogenous ADO exerts a tonic inhibitory influence on granulocytes during LTB4 stimulation and this action can be unmasked with methylxanthines.

Topics: Animals; Capillary Permeability; Cell Count; Cheek; Cricetinae; Dose-Response Relationship, Drug; Double-Blind Method; Drug Synergism; Granulocytes; Histamine; Inflammation; Leukotriene B4; Male; Mesocricetus; Purinergic Antagonists; Random Allocation; Theophylline

Topics: Animals; Cheek; Chemotaxis, Leukocyte; Cricetinae; Hydroxyeicosatetraenoic Acids; Inflammation; Leukocytes; Leukotriene B4; Lipoxins; Male; Mesocricetus; Microcirculation; Mouth Mucosa; Muscle, Smooth, Vascular

The effects of dietary alpha-linolenate (18:3, n-3) and linoleate (18:2, n-6) on platelet-activating factor (PAF) production were examined. Rats were fed an alpha-linolenic acid-rich (perilla oil) diet or a linoleic acid-rich (safflower oil) diet for 6 wk, and polymorphonuclear leukocytes (PMN) were elicited by peritoneal injection of casein. The overall phospholipid content and composition as well as the subclass distribution of choline and ethanolamine glycerophospholipids in PMN were not altered by these diets. However, with the perilla oil diet their content of a putative precursor of PAF, 1-alkyl-2-arachidonoyl-sn-glycero-3-phosphocholine was approximately 50% of that with safflower oil diet. On exposure to various concentrations of FMLP, PAF formation by PMN in the perilla oil group was less than 50% of that by PMN in the safflower oil group. A larger difference in PAF productions by PMN in the two dietary groups was observed on their stimulation with calcium ionophore A23187. These results demonstrate that PAF production is modulated in some as yet unknown way by changing the alpha-linolenate/linoleate balance of the diet.

Topics: alpha-Linolenic Acid; Animals; Calcimycin; Dietary Fats, Unsaturated; Inflammation; Leukotriene B4; Linolenic Acids; Male; Neutrophils; Phosphatidylcholines; Phosphatidylethanolamines; Platelet Activating Factor; Radioimmunoassay; Rats; Rats, Inbred Strains

Calcitonin gene-related peptide (CGRP), but not substance P (SP), was found to inhibit edema-promoting actions of inflammatory mediators (histamine, leukotrine B4, 5-hydroxytryptamine) in vivo in the hamster cheek pouch, human skin, and rat paw. The effect of CGRP was present in the low nanomolar dose range, and it was mimicked by activation of sensory nerves with capsaicin which caused release of endogenous CGRP-like immunoreactivity (IR). The findings provide new information on the potential impact of sensory nerve activation during inflammatory processes by indicating that sensory nerves may play an anti-inflammatory role.

Topics: Adult; Animals; Anti-Inflammatory Agents, Non-Steroidal; Calcitonin Gene-Related Peptide; Capsaicin; Cricetinae; Edema; Female; Histamine; Humans; Inflammation; Leukotriene B4; Male; Middle Aged; Mouth Mucosa; Rats; Serotonin; Skin; Skin Physiological Phenomena; Substance P

Substance P (SP) is a neuropeptide that has recently been implicated in the pathogenesis of neurogenic inflammation. SP has been shown to activate polymorphonuclear leukocytes (PMN) as well as other inflammatory cells. The present study investigated the direct stimulatory and priming effects of SP on canine PMN aggregation and migration. Direct stimulation of cell migration by SP was present at an unphysiologically high concentration of the mediator. However, when micromolar concentrations of SP were added to PMN prior to stimulation with sub-optimal concentrations of leukotriene B4 (LTB4), the cells exhibited enhanced aggregation and migration, i.e. priming, when stimulated with the latter. Since SP has been reported to act via the formyl-Met-Leu-Phe (fMLP) chemotaxin receptor, this mediator was also studied and found not to possess any effects similar to SP. Thus, the results indicate that SP acts as a primer of canine PMN functions in vitro via a receptor different from that for fMLP. Before ascribing SP a mediator role in canine neurogenic inflammation, in vivo studies determining the concentrations of, and responses to SP in inflamed tissue should be performed.

Topics: Animals; Cell Aggregation; Cells, Cultured; Chemotaxis, Leukocyte; Dogs; Dose-Response Relationship, Drug; Inflammation; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Phagocytosis; Substance P

Endotoxin-induced uveitis (EIU) can be produced by systemic injection of endotoxin (ET). It is not clear yet why exclusive ocular involvement occurs in this model. To clarify this question and to establish the sequence of inflammatory events, EIU was induced in Lewis rats by footpad injection of Salmonella ET. Ocular inflammatory response (anterior chamber cells and proteins), aqueous inflammation mediators (thromboxane B2, prostaglandin E2, leukotriene B4 and substance P) and MHC class 2 (Ia) antigen expression in the ciliary body were monitored for 72 hours. Thromboxane B2 was detected early in the aqueous humor, peaking already 1 hour after ET injection. Prostaglandin E2 & leukotriene B4 peaks and a second peak of thromboxane B2 were recorded 18 hours after ET-injection, at the time of maximal ocular inflammation. MHC-class 2 expression was first detected in the ciliary body stroma at the vascular level 6 hours after ET injection and was massively expressed in the ciliary body epithelium at 18 and 72 hours. It is hypothesized that ciliary body endothelium is particularly sensitive to the effect of ET and is the site of thrombocyte adherence. Vascular damage leads in succession to cellular infiltration, release of inflammation mediators and disruption of blood-ocular barrier. MHC-class 2 expression is a secondary phenomenon and is probably at the origin of additional tissue damage from immune effector mechanisms.

Topics: Animals; Aqueous Humor; Bacterial Toxins; Cell Count; Ciliary Body; Dinoprostone; Endotoxins; Enterotoxins; Eye Proteins; Histocompatibility Antigens Class II; Inflammation; Leukotriene B4; Male; Rats; Rats, Inbred Lew; Substance P; Thromboxane B2; Uveitis

The studies described here, using enantiomers of an optically-active methoxy alkyl thiazole ICI216800 (1-methoxy-6-(naphth-2-yl-methoxyl)-1- (thiazol-2-yl)indane), provide unequivocal evidence for a specific, chiral interaction with 5-lipoxygenase. In accordance with their biochemical efficacy these compounds also demonstrate enantio-specific anti-inflammatory activity in a leukotriene-mediated model of inflammation. This is the first class of compounds for which 5-lipoxygenase inhibition and anti-inflammatory activity have been shown to be mediated via a specific chiral interaction.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Eicosanoids; Humans; In Vitro Techniques; Indans; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Rabbits; Rats; Stereoisomerism; Thiazoles

Leukotrienes (LTs) have been implicated as mediators of the inflammation and ulceration associated with ulcerative colitis and Crohn's disease. In the present study, the effects of a novel, orally active inhibitor of LT synthesis (MK-886) were examined in a rat model of chronic colitis. Colitis was induced by intracolonic administration of trinitrobenzenesulfonic acid. Colonic LTB4 synthesis was measured after incubation of tissue samples in vitro and by in vivo equilibrium dialysis. A single dose of MK-886 (10 mg/kg) significantly inhibited colonic LTB4 synthesis for greater than 24 h. Daily treatment with this dose significantly reduced colonic damage, as assessed macroscopically and histologically, when the treatment was performed 2 h before induction of colitis and daily thereafter for 1 wk, but not when treatment was performed during the second week after induction of colitis. A less marked beneficial effect of MK-886 was observed when the pretreatment dose was excluded, suggesting a role for LTs in the early events of the inflammatory process. Inhibition of LT synthesis during the first 24 h after induction of colitis did not alter the extent of infiltration of neutrophils into the colon, as measured by tissue myeloperoxidase activity. Daily treatment with sulfasalazine (100 mg/kg po) either during the first or second week after induction of colitis did not significantly affect the rates of healing. At the dose used, sulfasalazine only produced a transient inhibition of colonic LTB4 synthesis. This study therefore demonstrates that a specific, orally active inhibitor of LT synthesis can significantly accelerate healing in this animal model of colitis when the treatment is performed during the early phase of the inflammatory response.

Topics: Administration, Oral; Animals; Colitis, Ulcerative; Colon; Disease Models, Animal; Indoles; Inflammation; Leukotriene B4; Male; Rats; Rats, Inbred Strains; Sulfasalazine; Trinitrobenzenesulfonic Acid

The role of neutrophil chemoattractant receptors in neutrophil stimulation in vitro is well established, however, the precise mechanisms underlying local neutrophil accumulation at inflammatory sites in vivo have not been defined. A fundamental question that remains open is whether chemoattractants act on the endothelial cell or the neutrophil to initiate the process of neutrophil migration in vivo. To address this question we have investigated whether neutrophil accumulation in vivo can occur if chemoattractant receptor occupancy is uncoupled from neutrophil stimulation. For this purpose we have used pertussis toxin (PT) as the pharmacologic tool. We have investigated the effect of in vitro pretreatment of rabbit neutrophils with PT on their responses in vitro and on their accumulation in vivo. Pretreatment of rabbit neutrophils with PT inhibited FMLP- and C5a-, but not PMA- induced increases in CD18 expression, neutrophil adherence, and degranulation in vitro. This pretreatment procedure with PT inhibited the accumulation of radiolabeled neutrophils in vivo in response to intradermally injected FMLP, C5a, C5a des Arg, leukotriene B4, IL-8, and zymosan in rabbit skin. Further, in contrast to the in vitro results, PT inhibited the PMA-induced 111In-neutrophil accumulation in vivo. Interestingly, pretreatment of neutrophils with PT also inhibited accumulation in response to intradermally injected IL-1, despite the reports that IL-1 lacks neutrophil chemoattractant activity in vitro. Although the experimental techniques used cannot distinguish the different stages of neutrophil migration involved, these results suggest that the accumulation of neutrophils induced by local extravascular chemoattractants in vivo depends on a pertussis toxin-sensitive receptor operated event on the neutrophil itself. Further, PMA and IL-1 may release secondary chemoattractants in vivo.

Topics: Animals; CD18 Antigens; Cell Adhesion; Cell Aggregation; Cell Degranulation; Complement C5a; Inflammation; Interleukin-1; Interleukin-8; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Pertussis Toxin; Rabbits; Receptors, Leukocyte-Adhesion; Recombinant Proteins; Skin; Tetradecanoylphorbol Acetate; Virulence Factors, Bordetella; Zymosan

An inflammatory response was elicited in the rabbit eye by intravitreal injection of endotoxin. The appearance in aqueous humor of selected metabolites of arachidonic acid metabolism at various times was correlated with the influx of protein and myeloperoxidase activity in the iris-ciliary body. After intravitreal injection of endotoxin, aqueous humor protein levels increased substantially within 2 hr. This aqueous humor protein increase occurred before a significant appearance of prostaglandin E2 (PGE2) in the aqueous humor. Myeloperoxidase activity in the iris-ciliary body, a measure of polymorphonuclear leukocyte (PMN) infiltration, showed little elevation until 6 hr after endotoxin injection and then increased rapidly through 24 hr. The appearance of the leukotriene B4 (LTB4) followed a similar time course: levels in the aqueous humor were partially elevated until 6 hr after endotoxin injection, when levels begin to rise rapidly. These findings are interpreted to demonstrate the dependence of PMN infiltration on the release and accumulation of LTB4; the initial breakdown of the blood-aqueous barrier and influx of protein appears to be independent of significant release of PGE2.

Topics: Animals; Aqueous Humor; Ciliary Body; Dinoprostone; Endotoxins; Eye Proteins; Inflammation; Iris; Leukotriene B4; Lipopolysaccharides; Neutrophils; Peroxidase; Rabbits; Time Factors

We systematically observed the effects of lipoxygenase enzyme products (5-, 8-, 9-, 12-, and 15-HETE and leukotrienes (LT) C4, D4, and B4) on the external ocular inflammatory process in rabbits. Our results, using 1 and 10 micrograms enzymatic preparations topically applied to the conjunctiva, were consistent with the potent chemotactic activity of 12-HETE and LTB4. Modulation of the inflammatory process can be accomplished better, as a result of our findings, by inhibition of both the lipoxygenase and cyclooxygenase pathways.

Topics: Animals; Arachidonic Acids; Chromatography, High Pressure Liquid; Conjunctiva; Eye; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; Leukotrienes; Lipoxygenase; Oxygen; Rabbits; SRS-A

Release of arachidonic acid metabolites (eicosanoids) by alveolar macrophages may be important in regulating pulmonary inflammatory reactions. The purpose of this study was to characterize eicosanoids released by rat alveolar macrophages during the evolution of experimentally induced pulmonary inflammation. Immunization with subcutaneous bacillus Calmette-Guerin (BCG) followed 2 wk later by intravenous BCG challenge resulted in mild granulomatous pulmonary inflammation for up to 30 days. At serial intervals, alveolar macrophages were lavaged from the BCG-treated rats as well as from control normal rats. Lavaged macrophages were cultured in vitro, and culture supernatants were assayed by radioimmunoassay for release of prostaglandin E2 (PGE2), Leukotriene B4 (LTB4), and thromboxane B2 (TXB2). Cells were cultured alone, or with added LPS or calcium ionophore A23187 to stimulate eicosanoid release. During BCG-induced inflammation, spontaneous release of PGE2 and LTB4 was unchanged, while spontaneous release of TXB2 was depressed acutely and then returned to control levels. The capacity of alveolar macrophages to release specific eicosanoids in response to an in vitro stimulus was dramatically altered during the course of BCG-induced inflammation. Stimulated release of PGE2 was transiently increased during acute lung injury, but stimulated release of LTB4 was significantly decreased at all stages of inflammation. Stimulated release of TXB2 was unchanged. These results indicate that during the course of granulomatous pulmonary inflammation there are dynamic changes in the profile of eicosanoids released by alveolar macrophages, both spontaneously and in response to in vitro stimulation. This alteration in the release of eicosanoids by alveolar macrophages may be an important factor in the resolution of pulmonary inflammation.

Topics: Animals; Bronchoalveolar Lavage Fluid; Cells, Cultured; Culture Media; Dinoprostone; Eicosanoids; Granuloma; Inflammation; Leukotriene B4; Lung Diseases; Macrophages; Male; Mycobacterium bovis; Pulmonary Alveoli; Radioimmunoassay; Rats; Rats, Inbred F344; Thromboxane B2

LTB4 is a potent mediator of inflammation acting at local sites of inflammation. LTB4 increases the lymphocyte binding to and penetration through the endothelium. In this paper we demonstrate that while endothelial cells were unable to metabolize LTB4 from arachidonic acid they were able to hydrolyse LTA4 into LTB4 in a granulocyte-endothelial co-culture assay. This hydrolysis is markedly increased if endothelial cells were pretreated with IFN-gamma prior to the assay. The IFN-gamma induced effect was shown to be time- and dose-dependent. The ability of endothelial cells to hydrolyse LTA4 to LTB4 may provide an answer how LTB4 can be produced in large quantities by nonheamatopoetic cells (i.e. by endothelial cells) at sites of acute inflammation.

Topics: Animals; Cell Adhesion; Endothelium, Vascular; Granulocytes; Hydrolysis; In Vitro Techniques; Inflammation; Interferon-gamma; Leukotriene A4; Leukotriene B4; Leukotrienes; Lymphocytes; Rats; Rats, Inbred Strains

Mobilization of circulating neutrophils toward an inflamed area involves adherence of the cells to the vascular endothelium and subsequent penetration through the endothelial cell layer without causing significant damage. To investigate the nature of a possible protective mechanism, granulocytes were incubated with the extracellular matrix (ECM) produced by cultured endothelial cells and tested for release of enzymes, chemoattractants, and free oxygen radicals. In the absence of exogenously added stimuli, the neutrophils adhered to the ECM but there was no detectable release of lysozyme, chemotactic activity, or production of O2-. In contrast, the cells readily released a heparan sulfate-degrading endoglycosidase (heparanase) to an extent comparable with that released in contact with polystyrene surfaces. Neutrophils treated with the calcium ionophore A23187 or with the peptide FMLP produced O2- to a much lesser degree when incubated in contact with ECM-coated surfaces than did those incubated in contact with uncoated polystyrene culture dishes. The ECM itself was devoid of superoxide dismutase activity. Stimulation with opsonized zymosan was not inhibited by the ECM. Experiments with isolated constituents of the ECM revealed that fibronectin but not collagen type IV or laminin could partially inhibit O2- production by Ca2+ ionophore-stimulated neutrophils. Treatment of the ECM with proteolytic enzymes, but not with heparanase, abolished its inhibitory effect on neutrophil activation. These results indicate that the subendothelial basement membrane has the capacity to inhibit release of potentially noxious agents excluding heparanase, suggesting a preferential involvement of this enzyme in neutrophil diapedesis.

Topics: Cell Adhesion; Cell Communication; Cells, Cultured; Chemotaxis, Leukocyte; Endothelium, Corneal; Extracellular Matrix; Humans; Inflammation; Kinetics; Leukotriene B4; Microscopy, Electron, Scanning; Neutrophils; Proteoglycans; Sulfates; Sulfur Radioisotopes; Superoxides; Time Factors

Exogenous [3H]leukotriene B4 (LTB4) was converted into several polar and non-polar metabolites in the chopped human lung. One of the major metabolites was identified as 5(S),12-dihydroxy-6,8,14-eicosatrienoic acid (10,11-dihydro-LTB4) by means of co-chromatography with authentic standards, ultraviolet spectrometry and gas chromatography-mass spectrometry. Analysis of chiral straight phase HPLC revealed the presence of both the 12(S) and 12(R) epimers of dihydro-LTB4. Dihydro-LTB4 was also formed from endogenously generated LTB4 in ionophore A23187 stimulated incubations. The dihydro metabolites were approximately 100 times less potent than LTB4 in causing guinea pig lung strip contraction and leukocyte-dependent inflammation in the hamster cheek pouch in vivo.

Topics: Animals; Cricetinae; Guinea Pigs; Humans; Inflammation; Leukotriene B4; Lung

Systemic injection of bacterial endotoxin (Lipopolysaccharide, LPS) in experimental animals induces anterior uveitis without major pathological changes in other organs. The present study investigates the effect of LPS on production of inflammatory mediators in cultured bovine pigmented ciliary epithelial cells (CB-cells) by means of radioimmunoassays and bioassays. LPS was found to stimulate CB-cells to secrete prostaglandin E2 and prostacyclin (assayed as its stable metabolite 6-keto-prostaglandin F1a), but not leukotriene B4 or thromboxane A2 (assayed as its stable metabolite thromboxane B2). CB-cells produced membrane-associated interleukin 1-activity in response to LPS, but no tumor necrosis factor-activity was found after challenge of CB-cells with LPS. The direct effect of LPS on production of inflammatory mediators by cells from the anterior uvea could play a role in the pathophysiology of endotoxin-induced uveitis.

Topics: Animals; Cattle; Cells, Cultured; Ciliary Body; Dinoprostone; Epithelium; Epoprostenol; Inflammation; Interleukin-1; Leukotriene B4; Lipopolysaccharides; Radioimmunoassay; Thromboxane A2; Tumor Necrosis Factor-alpha; Uveitis

Dietary polyunsaturated fatty acid modulation has been used as an anti-inflammatory strategy in experimental models of disease as well as in clinical trials. To elucidate the mechanisms underlying the anti-inflammatory effects of manipulating dietary polyunsaturated fatty acids, the in vivo effects of essential fatty acid (EFA) deficiency and (n-3) fatty acid supplementation were contrasted using a model of acute inflammation induced by the i.p. injection of zymosan into mice. Both diets led to a substantial decrease in tissue (n-6) fatty acid content. EFA deficiency was also characterized by the accumulation of (n-9) fatty acids, particularly 20:3 (n-9), the fatty acid that uniquely characterizes the deficiency state. Dietary (n-3) fatty acid supplementation led instead to marked increases in (n-3) fatty acids, especially 20:5 (n-3). With respect to the antiinflammatory effects of the two diets, EFA deficiency, but not (n-3) fatty acid supplementation, depleted levels of resident peritoneal macrophages. EFA deficiency was also more effective than (n-3) fatty acid supplementation in inhibiting the influx of polymorphonuclear neutrophils in response to zymosan. The effect of the two diets on the in vivo generation of leukotriene(LT)B also differed markedly. EFA deficiency completely inhibited the synthesis of LTB. Dietary (n-3) fatty acid supplementation, in contrast, reduced the production of LTB4 by only 50%. With (n-3) fatty acid supplementation LTB5 was produced. The more modest effect of (n-3) fatty acid supplementation in decreasing LTB4 generation was not due to blockade of the cyclooxygenase pathway. EFA deficiency, but not (n-3) fatty acid supplementation, was associated with the decreased synthesis of thromboxane. Although dietary fatty acid modulation has been shown to diminish platelet activating factor (PAF) synthesis, studies using the PAF receptor blocker, L659989, established that PAF was not a significant factor in the elicitation of leukocytes in this model of inflammation. In summary, the anti-inflammatory effect of EFA deficiency was more marked that that of dietary (n-3) fatty acid supplementation in acute inflammation. This difference in anti-inflammatory potential appeared to be due to either the greater effect of EFA deficiency in decreasing levels of resident peritoneal macrophages or in suppressing the in vivo generation of LTB4.

Topics: Acute Disease; Animals; Dietary Fats; Eicosanoids; Fatty Acids, Essential; Fatty Acids, Unsaturated; Furans; Inflammation; Leukotriene B4; Liver; Macrophages; Mice; Mice, Inbred C57BL; Platelet Membrane Glycoproteins; Receptors, Cell Surface; Receptors, G-Protein-Coupled

Topics: Animals; Chemotaxis, Leukocyte; Complement System Proteins; Fever; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Neutrophils; Nociceptors; Prostaglandins

Locally administered 9Ds-hydroxy-10,12(E,Z)-octadecadienoic acid (9-HODE) caused a drastic inflammatory response in the experimental model of granulation tissue formation of the rat according to RUDAS (Arzneimittelforsch. 10,226-229, 1960). Three days after implantation of the polyvinyl chloride rings the granulation tissue became inhomogeneous with proliferation islets surrounded by edematous regions containing a diminished number of cells. The number of polymorphonuclear leukocytes and of macrophages was greatly enhanced in the whole tissue, whereas the number of lymphocytes was reduced. After seven days the whole granulation tissue was loosened, and its mass was twice as high as in the control animals. The number of fibroblasts per area unit and the hydroxyproline content were diminished. Linoleic acid and 13Ls-hydroxy-9,11(Z,E)-octadecadienoic acid (13-HODE) caused also some changes in the formation of granulation tissue, but in a different manner, in particular, without accumulation of polymorphonuclear leukocytes and macrophages, indicating the specificity of the effect of 9-HODE. The recruitment of leukocytes was not due to a direct chemotactic action of 9-HODE as shown in an agarose diffusion test comparing the effects of 9-HODE and leukotriene B4. The possible biological importance of the proinflammatory effect of 9-HODE is discussed.

Topics: Animals; Chemotaxis, Leukocyte; Fibroblasts; Foreign-Body Reaction; Granulation Tissue; Inflammation; Leukotriene B4; Linoleic Acid; Linoleic Acids; Linoleic Acids, Conjugated; Macrophages; Male; Neutrophils; Prostheses and Implants; Rats; Wound Healing

Inflammation constitutes the body's principal mode of defense against infection and other harmful agents. Neutrophil leukocytes are the primary effector cells in this process. The role of protein synthesis in neutrophil emigration into acute inflammatory lesions was examined. Local intradermal injections of actinomycin D, cycloheximide or puromycin could inhibit in a dose- and time-dependent manner neutrophil emigration induced by interleukin-1, tumor necrosis factor alpha or endotoxin, but not by the leukocyte chemoattractants C5a des arg (zymosan-activated plasma), n-formyl-methionyl-leucyl-phenylalanine or leukotriene B4. Maximal inhibition, measured at the time of peak emigration, was greater than 90%. The onset of neutrophil emigration induced by the cytokines or by endotoxin was delayed by 30 to 60 minutes in comparison to the leukocyte chemoattractants. These results demonstrate at least two mechanisms of neutrophil emigration: one with a slower onset and dependence on local RNA transcription and translation and the other rapid in onset and independent of protein synthesis.

Topics: Animals; Chemotactic Factors; Complement C5; Complement C5a, des-Arginine; Cycloheximide; Dactinomycin; Endotoxins; Inflammation; Interleukin-1; Kinetics; Leukotriene B4; Neutrophils; Protein Biosynthesis; Protein Synthesis Inhibitors; Proteins; Puromycin; Rabbits; RNA; Transcription, Genetic; Tumor Necrosis Factor-alpha

The rabbit hydronephrotic kidney (HNK) is a model of renal inflammation characterized by a marked increase in arachidonic acid metabolism that is temporally associated with an inflammatory cell influx into the injured tissue. The HNK exhibits an exaggerated elaboration of eicosanoids ex vivo in response to either bradykinin or the inflammatory cell agonist n-formyl-methionyl-leucyl-phenylalanine (fMLP) compared with the unobstructed contralateral kidney. To pharmacologically manipulate inflammatory cell influx into the HNK we administered ethoxyquin (200 mg/kg p.o.), a combined cyclooxygenase/lipoxygenase inhibitor, RS-5186 (10 mg/kg p.o.), a thromboxane synthase inhibitor or L-659,989 (5 mg/kg p.o.), a platelet activating factor antagonist, before and at various times during the development of hydronephrosis. Only ethoxyquin reduced inflammatory cell influx into the HNK and thereby prevented the enhancement of microsomal cyclooxygenase activity and attenuated the elaboration of eicosanoids ex vivo. Collectively, these results suggest a primary role of an eicosanoid, possibly leukotriene B4, but not thromboxane A2 or the chemotactic phospholipid, platelet activating factor, as a mediator of inflammatory cell influx resulting from ureter obstruction.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Cyclooxygenase Inhibitors; Ethoxyquin; Fatty Acids, Nonesterified; Furans; Hydronephrosis; Inflammation; Kidney; Leukotriene B4; Lipoxygenase Inhibitors; Male; Perfusion; Platelet Activating Factor; Quinolines; Rabbits; Thiophenes; Thromboxane-A Synthase

In this study the, in vitro, influence of arachidonic acid metabolites on human beta-adrenoceptors was investigated. Incubation of normal human pulmonary membranes with PAF, LTB4 and LTC4 affected pulmonary beta-adrenoceptor properties, as was shown in radioligand binding studies. The same mediators were able to induce a decreased lymphocyte cAMP synthesis. It is concluded that beta-adrenoceptor deficiencies, that can be demonstrated in peripheral lung tissue of COLD patients, may result from pathological processes such as inflammation.

Topics: Arachidonic Acids; Cyclic AMP; Humans; Inflammation; Leukotriene B4; Lung; Lymphocytes; Platelet Activating Factor; Radioligand Assay; Receptors, Adrenergic, beta; SRS-A

Prostaglandin E levels have previously been demonstrated to be elevated in multiple sclerosis (MS). We have further investigated other products of activated macrophages related to inflammation. We report here on prostaglandin E and its relationship to interleukin 1, tumor necrosis factor, and leukotriene B4 produced by macrophages from blood and cerebrospinal fluid of MS patients and controls in vitro. Interleukin and tumor necrosis factor are elevated significantly after stimulation in MS, while leukotriene B4 production by blood macrophages is depressed compared to other neurological disease and normal healthy controls. In 40% of MS patients tested, peripheral blood macrophages spontaneously produced elevated levels of interleukin 1. All mediators of inflammation are produced in increased amounts by MS cerebrospinal fluid leukocytes after stimulation. Macrophages from MS blood are not as sensitive as controls to nonsteroidal inhibitors specific for lipoxygenase or cyclo-oxygenase pathways. Positive correlations of elevations in production of such mediators of inflammation as prostaglandin E, interleukin 1, and tumor necrosis factor in MS were significant. Elevated production of these mediators in combination with insensitivity to inhibitors of inflammation suggests a role for activated macrophages in the demyelination process.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Cells, Cultured; Female; Humans; Inflammation; Interleukin-1; Leukotriene B4; Macrophages; Male; Multiple Sclerosis; Neuromuscular Diseases; Prostaglandins E; Tumor Necrosis Factor-alpha

The arachidonic acid metabolism of guinea pig eosinophils isolated from either peritoneal cavity or bronchoalveolar lavages was studied by reverse-phase high-performance liquid chromatography. The purified eosinophils (95-100%) from either source released thromboxane B2 (TxB2), luekotriene B4 (LTB4) and 5-hydroxy eicosatetraenoic acid (5-HETE) following calcium ionophore A23187 stimulation. Quantification by radioimmunoassay indicated that maximal mediator output from the stimulated peritoneal cells was reached at 3 min after stimulation. The increase in production of TxB2 and LTB4 was correlated to increasing calcium ionophore A23187 concentration up to 1.0 micrograms/ml. In addition to calcium ionophore, the guinea pig peritoneal cells were also activated by f-met-leu-phe, phorbol 12-myristate, 13-acetate (PMA), and to lesser extent platelet-activating factor (PAF) to produce TxB2. LTB4 synthesis was stimulated by calcium ionophore, by f-met-leu-phe, as well as by unopsonized glucan, a particulate phagocytotic stimulus. The guinea pig eosinophils do not synthesize sulfidopeptide leukotrienes because of the absence of the specific LTA4 glutathione S-transferase. These results suggest that the guinea pig eosinophils differ from the human circulating eosinophils in the synthetic capacity of lipid mediators derived from arachidonic acid metabolism. This difference may be important in the understanding of the role of the eosinophils in inflammatory reactions such as that which occurs in the bronchial tissues of asthmatics.

Topics: Animals; Arachidonic Acids; Chromatography, High Pressure Liquid; Eosinophils; Female; Guinea Pigs; Inflammation; Leukotriene A4; Leukotriene B4; Leukotrienes; Radioimmunoassay; Thromboxane B2

Essential fatty acid (EFA) deficiency, induced by elimination of the dietary (n-6) fatty acids, has been shown to limit inflammatory cell influx and consequent enhanced eicosanoid production in experimental glomerulonephritis and hydronephrosis. To determine whether EFA-deficiency exerts anti-inflammatory effects following left ventricular myocardial infarction (LVMI), male weanling rabbits were fed EFA-deficient diet for 3 months prior to 60 minutes of distal left circumflex coronary artery occlusion followed by reperfusion. One and 4 days later, corresponding to infiltration of cardiac tissue with polymorphonuclear (PMN) and mononuclear leukocytes respectively, infarcted hearts were buffer perfused and stimulated to produce eicosanoids with f-met-leu-phe or bradykinin. One day following LVMI, the hearts of EFA-deficient rabbits demonstrated a marked suppression of PMN infiltration and eicosanoid production relative to controls. Four days following myocardial infarction, no differences were observed in mononuclear cell invasion, collagen deposition, or eicosanoid production between EFA-deficient and normal hearts. Our data show that EFA-deficiency inhibits PMN influx and consequent enhanced eicosanoid production without affecting the later appearance of mononuclear cells, collagen deposition, or eicosanoid production. Recent studies have shown that suppression of PMN invasion limits the extent of tissue damage following LVMI. Selective inhibition of PMN infiltration is possible and may be useful in the management of acute myocardial infarction.

Topics: 6-Ketoprostaglandin F1 alpha; Acute-Phase Reaction; Animals; Cell Migration Inhibition; Collagen; Dinoprostone; Fatty Acids, Essential; Inflammation; Leukotriene B4; Male; Myocardial Infarction; Myocardium; Neutrophils; Rabbits; Thromboxane B2

Des-Phe8-Arg9-BK could be detected in the entire course of rat carrageenin pleurisy up to 24 h, together with a reduction of the residual levels of high molecular weight kininogen and prekallikrein. On the basis of this continuous release of bradikinin, prostaglandin E2 was released up to 5 h in the pleural exudate and enhanced the plasma leakage. In rat cardiac infarction, the initial increase in the number of polymorphonuclear leukocytes in the cardiac tissue was accompanied by leukotriene B4 in the tissue and this was followed by the second increase and activation of the complement system.

Topics: Animals; Bradykinin; Cell Movement; Dinoprostone; Inflammation; Kallikreins; Leukocyte Count; Leukotriene B4; Neutrophils; Pleural Effusion; Rats; Time Factors

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonate Lipoxygenases; Arthritis, Experimental; Carrageenan; Cyclooxygenase Inhibitors; Dinoprost; Edema; Inflammation; Leukemia, Basophilic, Acute; Leukotriene B4; Lipoxygenase Inhibitors; Mycobacterium; Phenols; Pyrazoles; Rats; Stomach Ulcer; Tumor Cells, Cultured; Zymosan

Interleukin-1 (IL-1) mediates a number of immunologic and physiologic responses associated with inflammation. A new model to monitor the primary effects of IL-1 and potential inhibitors on inflammation has been developed, which involves unilateral injection of 300 U of highly purified recombinant human IL-1 in mouse ears. Ear thickness of IL-1 injected ears increased 7-10-fold 24 hr posttreatment, concomitant with a corresponding increase in myeloperoxidase activity, suggesting that neutrophil influx contributes to this response. Administration of nonsteroidal antiinflammatory drugs did not influence the IL-1 effect in vivo. Inhibition of phospholipase A2 activity ameliorated the IL-1 stimulated inflammation; treatment with 10 mg/kg dexamethaxone eliminated approximately 80% of increased myeloperoxidase activity compared to control values. This model provides a well-defined in vivo assay with which to quantify the systemic effects of compounds capable of altering the activity of IL-1, and the data suggest that this mechanism may explain the unique efficacy of steroids as antiinflammatories.

Topics: Animals; Anti-Inflammatory Agents; Anti-Inflammatory Agents, Non-Steroidal; Disease Models, Animal; Female; Inflammation; Interleukin-1; Leukotriene B4; Mice; Mice, Inbred BALB C; Neutrophils; Peroxidase; Recombinant Proteins; Steroids

Topics: Animals; Capillary Permeability; Cheek; Cricetinae; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; Lipoxins; Male; Mesocricetus; Microcirculation

The mode of action of the dual inhibitors of eicosanoid metabolism, SK&F 86002 and SK&F 104493 was evaluated on inflammatory cell infiltration induced in mice by carrageenan, monosodium urate crystals, and arachidonic acid. The results were compared to those seen with standard antiinflammatory compounds. Inflammatory cell infiltration was inhibited by SK&F 86002. SK&F 104493, colchicine, and phenidone but not naproxen. In vivo, PMN infiltration induced by LTB4 was inhibited by colchicine but not by SK&F 86002, SK&F 104493, or phenidone treatment. Similarly, in vitro chemotaxis to LTB4 was not inhibited by SK&F 86002. The 5-lipoxygenase inhibitors, SK&F 86002, SK&F 104493, and phenidone inhibited LTB4 production in vivo as well as inflammatory cell infiltration induced by arachidonic acid. The data are consistent with the suggestion that the bicyclic imidazoles inhibit PMN infiltration by virtue of inhibition of LTB4 production.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Chemotaxis, Leukocyte; Cyclophosphamide; Dinoprostone; Ear Diseases; Edema; Eicosanoids; Imidazoles; Inflammation; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Neutrophils; Peritonitis; Pyridines; Thiazoles

Intravital microscopy and determination of in vivo histamine release revealed that the cyclooxygenase inhibitor indomethacin reduced antigen-induced vasodilation while enhancing plasma extravasation, leukocyte accumulation, and histamine release in cheek pouches of immunized hamsters. Topical application of prostaglandin E2 (PGE2, 30 nM) totally reversed the indomethacin-induced potentiation of the inflammatory reaction to antigen challenge and suppressed both the histamine release and plasma leakage also in the absence of indomethacin. On the other hand, PGE2, which per se caused vasodilation, markedly potentiated the postcapillary leakage of plasma induced by histamine or leukotriene C4, as well as the leukocyte activation and subsequent plasma extravasation evoked by leukotriene B4. Taken together, the data indicate that PGE2 reduced the antigen response by suppression of mediator release from the numerous mast cells present in the cheek pouch. Moreover, the PGE2-sensitive potentiation by indomethacin of the antigen response suggests that endogenous vasodilating prostaglandins (possibly PGE2) predominantly were anti-inflammatory.

Topics: Animals; Cricetinae; Cyclooxygenase Inhibitors; Dinoprostone; Histamine; Histamine Release; Hypersensitivity, Delayed; Indomethacin; Inflammation; Leukotriene B4; Male; Mesocricetus; Microcirculation; Prostaglandin-Endoperoxide Synthases; Prostaglandins E; SRS-A; Vasodilation

Essential fatty acid (EFA) deficiency exerts an anti-inflammatory effect in several models of inflammation. In an effort to understand underlying mechanisms, the effect of EFA deficiency on the generation of eicosanoids and the elicitation of leukocytes in a model of acute inflammation was examined. Acute inflammation was induced by the i.p. injection of zymosan in mice. The injection of zymosan in normal mice was followed by a short burst of eicosanoid synthesis lasting 2 hr. Leukotriene (LT)B4, LTC4, LTD4, and LTE4, thromboxane B2, and 6-keto-prostaglandin F1 alpha were detected using high pressure liquid chromatography and specific radioimmunoassays. This initial phase of eicosanoid production was followed by a more prolonged infiltration of leukocytes (predominantly polymorphonuclear neutrophils (PMN)) lasting 48 hr with little eicosanoid synthesis. When challenged with zymosan, EFA-deficient mice exhibited a marked decrease in the production of eicosanoids during the early phase. No LTB could be detected at all. The number of resident peritoneal macrophages in EFA-deficient mice was also substantially decreased, and the influx of PMN during the inflammatory response was markedly diminished. In order to establish that the generation of eicosanoids during the early phase of this model of acute inflammation played a causal role in the later infiltration of PMN, the effect of the mixed lipoxygenase/cyclooxygenase inhibitor, BW755C, on LTB formation and PMN influx in this model of inflammation was assessed in control animals. BW755C completely blocked LTB synthesis and inhibited the subsequent influx of PMN. In conclusion, EFA deficiency inhibits eicosanoid generation, depresses levels of resident macrophages, and markedly diminishes the influx of PMN in the acute inflammatory response. The decrease in PMN influx appears to result from the inhibition of the antecedent generation of LTB.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Animals; Fatty Acids, Essential; Inflammation; Leukotriene B4; Macrophages; Male; Mice; Pyrazoles

Monosodium urate (MSU) crystals induce an inflammatory response when injected into the rat subcutaneous air pouch, which is characterised by polymorphonuclear leucocyte (PMNL) accumulation and plasma leakage. The arachidonic acid metabolites leucotriene B4 (LTB4), prostaglandin E2 (PGE2), 6-oxo-prostaglandin F1 alpha, (6-oxo-PGF1 alpha), and thromboxane B2 (TXB2) are found in increased concentrations in MSU induced exudates compared with animals injected with phosphate buffered saline (PBS). Pretreatment of animals with BW 755c significantly reduced the concentration of both lipoxygenase and cyclo-oxygenase derived arachidonic acid metabolites. Although BW 755c reduced MSU crystal induced plasma leakage, it did not affect PMNL accumulation. Pretreatment of animals with indomethacin selectively inhibited the generation of cyclo-oxygenase derived arachidonic acid metabolites and reduced MSU crystal induced plasma leakage but had no effect on PMNL accumulation. The inhibition of plasma leakage by either BW 755c or indomethacin was reversed by prostaglandin E2 (1 microgram/ml), which itself produced a significant increase in plasma leakage. The injection of purified LTB4 (4 ng/ml or 40 ng/ml) did not induce either plasma leakage or PMNL accumulation within the air pouch. These data suggest that although MSU crystals stimulate LTB4 production, LTB4 is not the mediator of MSU crystal induced PMNL accumulation. Cyclo-oxygenase products of arachidonic acid metabolism (e.g., PGE2), however, appear to play a part in MSU crystal induced plasma leakage.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Animals; Anti-Inflammatory Agents, Non-Steroidal; Dinoprostone; Indomethacin; Inflammation; Leukocyte Count; Leukotriene B4; Male; Neutrophils; Prostaglandins E; Prostaglandins E, Synthetic; Pyrazoles; Rats; Rats, Inbred Strains; Uric Acid

Airway inflammation is thought to be an important determinant of bronchoconstriction and bronchial hyperreactivity. We have recently demonstrated that bronchoconstriction induced by an aqueous extract of cotton bracts (CBE) is associated with bronchoalveolar complement activation, release of polymorphonuclear neutrophil (PMN) chemoattractants by pulmonary cells, and increased numbers of bronchoalveolar lavage PMN's. In the present study we performed bronchoalveolar lavage (BAL) on subjects after CBE or control (saline) challenge and examined whether BAL cells were activated in vitro to produce other inflammatory agonists. After CBE administration, cultured BAL cells released increased amounts of the reactive O2 species, superoxide (O2-.), and the cyclooxygenase products prostaglandin E2 and thromboxane B2. Although none of these in vitro parameters of BAL cell activation appeared to correlate with the degree of bronchoconstriction induced by CBE, BAL fluid levels of thromboxane B2 were also increased after CBE administration and in vivo amounts of this eicasanoid did correlate with the degree of bronchoconstriction induced by CBE (r = 0.50, P less than 0.04). Finally, although cell culture supernatants were highly chemotactic for PMN's, concentrations of leukotriene B4 were not increased, suggesting other chemotaxins were released by BAL cells in this setting. We conclude that CBE administration activates bronchoalveolar cells to release reactive O2 species and cyclooxygenase products that may be important in the bronchoconstricting response to CBE.

Topics: Adult; Bronchi; Cells, Cultured; Chemotaxis, Leukocyte; Gossypium; Humans; Inflammation; Leukotriene B4; Lung Volume Measurements; Neutrophils; Plant Extracts; Pulmonary Alveoli; Reference Values; Therapeutic Irrigation

Topics: Animals; Arachidonate 5-Lipoxygenase; Cell Communication; Humans; Inflammation; Leukotriene B4; Oxidation-Reduction; Research; SRS-A

Topics: Cytotoxicity, Immunologic; Humans; Inflammation; Interferon-gamma; Interleukin-1; Interleukin-2; Leukocytes, Mononuclear; Leukotriene B4; Lymphocyte Activation; T-Lymphocytes, Helper-Inducer; T-Lymphocytes, Regulatory; Tumor Necrosis Factor-alpha

Glucocorticoids suppress the inflammatory response by altering leukocyte traffic and function, cytokine secretion and action, and phospholipid metabolism. We employed the glucocorticoid receptor antagonist RU 486, to examine whether glucocorticoids suppress the inflammatory response through a receptor-mediated mechanism and whether basal glucocorticoid secretion exerts antiinflammatory effects in the resting (non-stress) state. To test these hypotheses we evaluated the effects of increasing doses of dexamethasone, RU 486, or dexamethasone plus RU 486 on the exudate volume and concentrations of leukocytes, prostaglandin E2, (PGE2) and leukotriene B4 (LTB4) in intact rats that received subcutaneous carrageenin. Exudate volume, leukocyte concentration and LTB4 and PGE2 levels were all suppressed by dexamethasone in a dose-dependent fashion (P less than 0.005). RU 486 was able to antagonize fully the suppressive effects of dexamethasone on the inflammatory response (P less than 0.001) and to cause increases of exudate volume and leukocyte, PGE2 and LTB4 concentrations when given alone (P less than 0.05). These increases ranged between 30 and 100% above the basal inflammatory response. We conclude that glucocorticoids most likely suppress the inflammatory response by a glucocorticoid receptor-mediated mechanism and under basal conditions exert tonic antiinflammatory effects.

Topics: Alprostadil; Animals; Carrageenan; Dexamethasone; Estrenes; Glucocorticoids; Inflammation; Kinetics; Leukocytes; Leukotriene B4; Male; Mifepristone; Rats; Rats, Inbred Strains; Receptors, Glucocorticoid

1. Two selective inhibitors of arachidonate 5-lipoxygenase, BW A4C and BW A797C, have been studied for their effects on acute inflammatory responses following oral administration to rats and mice. 2. The concentrations of the lipoxygenase product leukotriene B4 (LTB4) in 6 h inflammatory exudates, induced in rats by the subcutaneous implantation of carrageenin-soaked polyester sponges, were reduced dose-dependently by BW A4C (ED50 = 2.6 mg kg-1) or BW A797C (ED50 = 14.3 mg kg-1). 3. BW A4C and BW A797C had little or no effect on prostaglandin E2 (PGE2) concentrations in inflammatory exudates (ED50s greater than 100 mg kg-1). 4. Doses of up to 200 mg kg-1 of either BW A4C or BW A797C had no effect on carrageenin-induced oedema in rat paws. 5. BW A4C and BW A797C had little or no effect on carrageenin-induced hyperalgesia in rats or phenyl-benzoquinone-induced writhing in mice. 6. Yeast-induced pyrexia in rats was reduced by both BW A4C (ED50 = 32 mg kg-1) and BW A797C (ED50 = 23 mg kg-1). 7. The accumulation of leucocytes in sponge exudates was reduced dose-dependently by BW A4C (ED50 = 54 mg kg-1) and BW A797C (ED50 = 16.7 mg kg-1). 8. The selective lipoxygenase inhibitors BW A4C and BW A797C do not suppress inflammatory oedema or pain although they are anti-pyretic and they do inhibit leucocyte migration. There is not, however, a close agreement between these in vivo activities and their potencies as lipoxygenase inhibitors.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Acute Disease; Animals; Arachidonate Lipoxygenases; Dinoprostone; Female; Hydroxamic Acids; Inflammation; Leukocyte Count; Leukotriene B4; Lipoxygenase Inhibitors; Male; Mice; Mice, Inbred Strains; Prostaglandins E; Pyrazoles; Rats; Rats, Inbred Strains

Prostaglandins are important regulators of inflammatory responses. The rat subcutaneous air pouch, a model for synovial inflammation, was used to study the effect of systemic injections of prostaglandin E1 (PGE1) and its stable analog 15S,15 methyl prostaglandin E1 (15M PGE1) on nonimmunologically induced acute inflammation. The 15M PGE1 analog was a more effective longer-lasting antiinflammatory agent. Acute inflammatory responses were induced with three diverse stimuli including monosodium urate crystals, leukotriene B4 and formylmethionylleucyl-phenylalanine. Animals were treated with 15 M PGE1 for 2 days before induction of inflammation. Analysis of pouch fluid 6 hours after injection of the inflammatory stimulus indicates that 15M PGE1 treatment suppressed exudate volume and protein concentration, polymorphonuclear leucocyte accumulation and activity of the lysosomal enzyme beta-galactosidase. Treatment with 15M PGE1 was least effective in preventing the fluid phase of inflammation (exudate volume and protein concentration) when leukotriene B4 was used to induce inflammation. Direct observation (dissecting microscope) of pouch lining vessels indicated that 15M PGE1 reduced markedly the intense vascular reactivity (increased number of dilated vessels and filamentous, corkscrew-shaped vessels) usually seen in an acute inflammatory response. The antiinflammatory effect of 15M PGE1 was also documented by histopathology of pouch lining tissue. Treatment with 15M PGE1 reduced substantially the invasion of pouch tissue by polymorphonuclear leucocytes which was induced by all three stimuli of inflammation. Results of these experiments show that systemic administration of 15M PGE1 is capable of suppressing acute inflammation induced by monosodium urate crystals, by the potent soluble naturally occurring mediator of inflammation leukotriene B4, and by the synthetic chemotactic peptide, formylmethionylleucylphenylalanine.

Topics: Acute Disease; Alprostadil; Animals; Inflammation; Leukotriene B4; Male; N-Formylmethionine Leucyl-Phenylalanine; Rats; Rats, Inbred Strains; Uric Acid

Oxazolone-induced delayed hypersensitivity in mice produced swelling with concomitant increased tissue levels of leukotrienes and prostaglandins. Pharmacological agents were coapplied topically with oxazolone at the time of challenge in an attempt to modulate the immune-based inflammation. Dexamethasone inhibited both swelling and increases in eicosanoid levels. Indomethacin reduced prostaglandin levels but failed to inhibit swelling or reduce leukotriene levels. L-651,896 (2,3-dihydro-6-[3-(2-hydroxymethyl)phenyl-2-propenyl]-5-benzofuranol), a 5-lipoxygenase inhibitor, reduced leukotriene levels but did not reduce swelling or prostaglandin levels. A combination of indomethacin and L-651,896 reduced eicosanoid levels but did not reduce swelling. These data suggested that the reduction in tissue levels of 5-lipoxygenase or cyclooxygenase oxygenation products of arachidonic acid either singularly or together did not result in the concomitant reduction of the inflammation associated with oxazolone-induced delayed hypersensitivity.

Topics: Animals; Cyclooxygenase Inhibitors; Dexamethasone; Dinoprostone; Female; Hypersensitivity, Delayed; Inflammation; Leukotriene B4; Lipoxygenase Inhibitors; Mice; Oxazoles; Oxazolone; Prostaglandins E; SRS-A

In polymorphonuclear neutrophils, phospholipase A2 activity is the rate-limiting step for platelet-activating factor (PAF) formation and for the biosynthesis of arachidonic acid derivatives, leukotrienes and prostaglandins. Glucocorticosteroids inhibit phospholipase A2 activity by inducing in target cells the synthesis and release of phospholipase A2 inhibitory proteins named 'lipocortins'. Here, we report that rat pleural inflammatory polymorphonuclear neutrophils, treated with dexamethasone, decrease their production of eicosanoids and PAF. Evidence is presented which may implicate lipocortin 's' in these inhibitions since (i) phospholipase A2 inhibitory proteins are found in the supernatant of dexamethasone-treated cells, (ii) this supernatant inhibits the formation of lipid mediators in untreated cells, inhibition being reversed either by incubating the supernatant with a monoclonal antibody against rat lipocortin or by boiling it and (iii) a 36 kDa lipocortin from mice lungs mimics the effects of dexamethasone when added exogenously on untreated cells. Our results favour the hypothesis that the newly formed lipocortin 's' could be responsible for the antiphospholipase A2 activity of glucocorticosteroids.

Topics: Annexins; Calcimycin; Dexamethasone; Dinoprostone; Glycoproteins; Humans; Inflammation; Kinetics; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Phospholipases; Phospholipases A; Phospholipases A2; Platelet Activating Factor

The chemotactic activities of inflammatory cell products for rat aortic smooth muscle cells (SMC) were examined in modified Boyden chambers. A checker board analysis revealed that interleukin-1 (IL-1), leukotriene B4 (LTB4), platelet-derived growth factor (PDGF) and inflammatory exudate from zymosan-activated air pouches stimulated chemotaxis of SMC. The chemotaxis, irrespective of the attractants used, was strongly inhibited by nilvadipine, a potent calcium antagonist, and the IC50 values were around 1 x 10(-10) M. Removal of extracellular calcium abolished the chemotactic activities of the attractants. These results suggest that inflammatory cells such as macrophages and polymorphonuclear leukocytes (PMN) have an important role in the migration of SMC into the intima during atherogenesis, and that nilvadipine might be useful for preventing and treating atherosclerosis.

Topics: Animals; Aorta, Thoracic; Calcium; Calcium Channel Blockers; Cells, Cultured; Chemotaxis; Exudates and Transudates; Inflammation; Interleukin-1; Leukotriene B4; Male; Muscle, Smooth, Vascular; Nifedipine; Platelet-Derived Growth Factor; Rats; Rats, Inbred Strains

Radioligand binding studies using human neutrophils exposed to 10-100 microM dapsone indicated that this anti-inflammatory compound antagonized association of LTB4 (leukotriene B4) with its specific receptor sites. Binding inhibition was manifested in reduced biologic response of the neutrophils as determined in LTB4-stimulated chemotaxis. In addition, a physiologic model of LTB4-dependent inflammation in mice was antagonized by systemic administration of dapsone. These data suggest that inhibition of LTB4 binding may represent the cellular mechanism of action responsible for the anti-inflammatory effects of dapsone.

Topics: Animals; Chemotaxis, Leukocyte; Dapsone; Female; Humans; In Vitro Techniques; Inflammation; Leukotriene B4; Mice; Mice, Inbred BALB C; Neutrophils; Receptors, Immunologic; Receptors, Leukotriene B4

Using radioimmunoassay technique, levels of leukotriene B4 and C4 (LTB4 and LTC4) in the aqueous humor of rabbit eyes were measured following experimental nonpenetrating ocular trauma. Slit lamp examination showed a time-dependent increase of flare, cells, and fibrin in the anterior chamber of the traumatized eyes. Polymorphonuclear (PMN) leukocyte influx into the aqueous humor was not seen at 6 hours but increased significantly in traumatized eyes after 12 hours. No inflammatory cells were observed in control eyes. Histopathologic studies demonstrated injuries of the ciliary body, ruptures of the retina and choroid, with intraocular hemorrhage. LTB4 values peaked at 6 hours, prior to PMN cell infiltration and remained significantly higher than controls, which remained undetectable at all intervals after injury. LTC4 values also peaked by 6 hours in the traumatized eyes. These data demonstrate that elevations in LTB4 and LTC4 are associated with blunt trauma, and this precedes PMN cell infiltration. Leukotrienes may play a role in the early inflammatory response following concussive ocular injuries.

Topics: Animals; Aqueous Humor; Eicosanoic Acids; Eye Injuries; Inflammation; Leukotriene B4; Male; Rabbits; Radioimmunoassay; SRS-A; Wounds, Nonpenetrating

Adherence of polymorphonuclear leukocytes (PMNs) to endothelial cells (ECs) is a crucial step in the diapedesis of inflammatory cells to the site of inflammation. We have demonstrated that leukotriene B4 (LTB4), a metabolite of the arachidonic acid cascade, and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) significantly enhance the binding of human PMNs to selected populations of human dermal microvascular endothelial cells (MECs) in vitro. MECs were isolated from the vascular-rich portion of foreskins of newborns. MECs were grown in Iscove's modified Dulbecco's media with 2% prepartum serum and 8% newborn calf serum on 1% gelatin-coated plastic dishes. PMNs isolated from five human donors were added to the culture dishes for varying time intervals (usually 30 min) in the presence and absence of the chemotactic stimuli LTB4 and FMLP. Addition of PMNs to MECs in the absence of chemotactic stimuli results in "baseline" binding to the MEC monolayer. About one in every 150 ECs binds more than five PMNs. These selected ECs are randomly distributed throughout the monolayer. LTB4 from 10(-10) to 10(-7) M increases the number of MECs which selectively bind PMNs by 260% at 10(-7) M. FMLP also increases adherence in qualitatively and quantitatively similar fashion. These data support a role for LTB4 in the mediation of adherence of neutrophils to dermal MECs. In contrast to other endothelial cells from the large blood vessels, such as from umbilical veins or calf thoracic aortae, PMNs bind only to selected MECs in culture, even when stimulated with LTB4 or FMLP.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Cell Adhesion; Endothelium, Vascular; Humans; In Vitro Techniques; Inflammation; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Skin

Topics: Acute Disease; Animals; Cheek; Cricetinae; Inflammation; Leukotriene B4; Mesocricetus; Mouth Mucosa; Muscles; Platelet Activating Factor; Rabbits; Substance P

To assess the relative contribution of different leucocyte subpopulations to LTB4 production, peripheral blood leucocytes from human donors were separated into polymorphonuclear neutrophils (PMN) and lymphocytes/monocytes (L/M) and were then stimulated in vitro with the Ca-ionophore A 23187 for different times. The supernatants were analysed for their contents of leukotriene B4 (LTB4) and its omega-metabolites by HPLC-analysis and column fractions were also examined for their chemotactic activities towards eosinophils in vitro. PMN supernatants contained greater quantities of LTB4, 20-OH-LTB4, 20-COOH-LTB4, and chemotactic activities than did L/M supernatants. On the other hand, the time dependent decrease of LTB4 and chemotactic activity and the increase of omega-metabolites were higher in PMN than in L/M. These results would correlate with the greater role of PMN in acute and that of monocytes in chronic inflammation.

Topics: Calcimycin; Chemotaxis, Leukocyte; Chromatography, High Pressure Liquid; Humans; In Vitro Techniques; Inflammation; Leukotriene B4; Lymphocytes; Monocytes; Neutrophils; Time Factors

The effect of a diet enriched in fish-oil-derived fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DCHA) in inflammation and immunological processes in rats has been investigated. Rats on a normal chow diet were given 500 mg/kg/day EPA and 333 mg/kg/day DCHA by gavage over a period of 50 days. Control groups received water, oleic acid or safflower oil. Acute and chronic phases of inflammation induced by antigenic challenge with bovine serum albumin were examined in the rat air-pouch model. In rats receiving fish-oil-derived fatty acids, there was a reduced production of the arachidonic acid metabolites, prostaglandin E2 and leukotriene B4, in the exudate in the chronic phase of inflammation, but not in the acute phase. This was associated with an increased infiltration of leukocytes, especially monocytes and macrophages, in the chronic inflammatory phase. The fish-oil-supplemented diet showed no effect on the volume of inflammatory exudate, the amount of protein in the exudate and connective tissue proliferation. Carrageenin-induced paw edema in the animals was not influenced by the diet. There was no effect of the dietary fish oil on production of antibodies to bovine serum albumin in the rats. However, the diet appeared to suppress a delayed-type skin reaction in the animals. These studies suggest that fish-oil-derived fatty acids may modulate chronic inflammation and a cellular-mediated immunological reaction by reducing the synthesis of arachidonic acid metabolites.

Topics: Animals; Antibody Formation; Dinoprostone; Docosahexaenoic Acids; Edema; Eicosapentaenoic Acid; Fish Oils; Food, Fortified; Hypersensitivity, Delayed; Inflammation; Leukotriene B4; Male; Prostaglandins E; Rats; Rats, Inbred Strains

Two experimental models of acute non-immune inflammation have been developed to enable studies of the biochemical composition and cellular content of exudates to be undertaken. Both are based on the creation of a mild, reproducible and reversible inflammatory reaction, which is free from uncontrolled incidental factors and which causes minimal distress to the experimental animals. The polyester sponge model involves the insertion of small polyester sponge strips soaked in sterile carrageenan solution into subcutaneous neck pouches and their serial removal. The tissue-cage model is based on the initial insertion of a spherical tissue-cage subcutaneously in the neck and the subsequent stimulation with carrageenan of the granulation tissue which lines and permeates the cage. The acute inflammatory exudates have been shown to contain eicosanoids with prostaglandin E2 predominant. Polymorphonuclear leucocyte numbers increased progressively in the polyester sponge model, whereas cell numbers were maximal at 12 hours in the tissue-cage model. The relationships between eicosanoid formation at the site of inflammation and leucocyte accumulation, enzyme release, total protein content of exudates and the temperature of the lesions have been investigated.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Carrageenan; Dinoprostone; Disease Models, Animal; Exudates and Transudates; Horse Diseases; Horses; Inflammation; Leukotriene B4; Prostaglandins E; Proteins; Thromboxane B2

The migration of leucocytes to sites of acute and chronic inflammation is an event of central importance to the maintenance of inflammatory processes; extravascular leucocytes are responsible for generating chemical mediators of inflammation and the phagocytosis of particulate matter. They may also be involved in the conversion of acute to chronic inflammatory lesions. Leucocytes are attracted to sites of tissue injury by a range of chemoattractants. This paper describes the development of a method for separating on Percoll gradients purified populations of equine polymorphonuclear and mononuclear leucocytes and use of the isolated cells in vitro studies. Two independent assay methods, the agarose microdroplet and the Boyden chamber microfilter techniques, were used. The assays were utilised in three ways: (a) to investigate the sensitivity of polymorphonuclear and mononuclear leucocytes to two standard chemoattractants, zymosan activated plasma and n-formyl-methionyl-leucyl phenylalanine; (b) to study the chemoattractant properties of leukotriene B4 and prostaglandin E2 for equine leucocytes; and (c) to investigate the inhibitory actions of several nonsteroidal anti-inflammatory drugs (NSAIDs) on equine leucocyte movement.

Topics: Acute Disease; Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Migration Inhibition; Centrifugation, Density Gradient; Chemotaxis, Leukocyte; Chronic Disease; Dinoprostone; Horse Diseases; Horses; Immunity, Cellular; Inflammation; Leukocytes; Leukocytes, Mononuclear; Leukotriene B4; Neutrophils; Phagocytosis; Prostaglandins E

The effects of SK&F 86002 [5-(4-pyridyl)-6 (4-fluorophenyl)-2,3-dihydroimidazo (2,1-b) thiazole] on the generation of eicosanoids in vitro and on inflammatory responses in vivo are described and compared to other non-steroidal anti-inflammatory drugs. SK&F 86002 inhibited prostaglandin H2 (PGH2) synthase activity (IC50 120 microM) as well as prostanoid production by rat basophilic leukemia (RBL-1) cells (IC50 70 microM) and its sonicate (IC50 100 microM) and human monocytes (IC50 1 microM). In addition, SK&F 86002 inhibited the generation of dihydroxyeicosatetraenoic acid (diHETE) and 5-hydroxyeicosatetraenoic acid (5-HETE) by a high speed supernatant fraction of RBL-1 cells (IC50 10 microM). Cellular production of 5-lipoxygenase products was inhibited by SK&F 86002 as measured by leukotriene B4 (LTB4) generation from human neutrophils (IC50 20 microM), leukotriene C4 (LTC4) generation by human monocytes (IC50 20 microM), and 5-HETE production by RBL-1 cells (IC50 40 microM). The in vivo profile of anti-inflammatory activity of SK&F 86002 supports the dual inhibition of arachidonate metabolism as indicated by its activity in inflammation models that are insensitive to selective cyclooxygenase inhibitors. The responses of arachidonic-acid-induced edema in the mouse ear and rat paw, as well as the cell infiltration induced by carrageenan in the mouse peritoneum and by arachidonic acid in the rat air pouch, were inhibited by SK&F 86002 and phenidone but not by the selective cyclooxygenase inhibitors naproxen and indomethacin.

Topics: Animals; Anti-Inflammatory Agents; Arachidonate Lipoxygenases; Arachidonic Acid; Arachidonic Acids; Cyclooxygenase Inhibitors; Humans; Imidazoles; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Mice; Pyrazoles; Rats; SRS-A; Thiazoles

A newly synthesized compound, the non-steroidal antiinflammatory agent N-methoxy-3-(3,5-di-tert-butyl-4-hydroxybenzylidene)pyrrolidin-2-o ne (E-5110) was investigated. E-5110 inhibited prostaglandin E2 (PGE2) generation by cultured rat synovial cells upon stimulation with interleukin-1-like factor of rat polymorphonuclear leucocytes (PMN). The IC50 values (mumol/l) for PGE2 generation were 0.026 for E-5110, 0.008 for indometacin, 0.112 for piroxicam and 0.667 for the compound B (3-amino-1-(M-trifluoromethyl-phenyl-2-pyrazoline). Calcium ionophore A23187-stimulated leukotriene B4 generation by human PMN was inhibited by E-5110 with an IC50 value of 0.20 mumol/l; E-5110 was as inhibitory as nordihydroguaiaretic acid and was more potent than the compound B (IC50 of 2.58 mumol/l). E-5110 suppressed superoxide generation by human PMN stimulated with opsonized zymosan, f-Met-Leu-Phe and phorbol myristate acetate. E-5110 also inhibited the generation of leucocytic pyrogen and leucocyte factor(s) which stimulated collagenase production by cultured synovial cells.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Dinoprostone; Humans; Indomethacin; Inflammation; Interleukin-1; Leukocytes; Leukotriene B4; Piroxicam; Prostaglandins E; Pyrogens; Pyrrolidinones; Rats; Superoxides

Hyperalgesia onset latencies of inflammatory mediators were quantified by measuring the threshold of the nociceptive flexion reflex in the rat at 1 min intervals after intradermal injection. Prostaglandin E2 and 8(R), 15(S)-dihydroxyicosa-(5E,9,11,13Z)-tetraenoic acid induced hyperalgesia with short onset latencies, compatible with a direct action on primary afferent nociceptors. Bradykinin, norepinephrine and leukotriene B4 induced hyperalgesia with a significant delay in onset, compatible with their known indirect mechanisms of producing hyperalgesia. We propose that use of this approach, rapid frequent measurement of nociceptive threshold, can be used to determine the hierarchy of action of mediators in hyperalgesic mechanisms.

Topics: Animals; Bradykinin; Dinoprostone; Hyperalgesia; Hyperesthesia; Inflammation; Leukotriene B4; Nociceptors; Norepinephrine; Pain; Prostaglandins E; Rats; Rats, Inbred Strains

Nordihydroguaiaretic acid (NDGA) was investigated for its ability to interact with leukotriene B4 receptors on human polymorphonuclear leukocytes (hPMNs). 3H-LTB4 binding to specific receptors was reduced in a dose-dependent manner with maximal reduction at 100 microM NDGA and an IC50 of about 50 microM. Binding of another inflammatory stimulus. N-formyl-norleucyl-leucyl-phenylalanine (FNLP) was not affected by similar treatment. Chemotaxis and enzyme release stimulated by LTB4 and oligopeptide were inhibited by NDGA. In addition, LTB4-triggered inflammation in vivo in mice was inhibited by systemic administration of NDGA. These data suggest that LTB4 receptor antagonism may contribute to inhibition of inflammation by NDGA.

Topics: Animals; Catechols; Humans; In Vitro Techniques; Inflammation; Leukotriene B4; Masoprocol; Mice; Neutrophils; Receptors, Immunologic; Receptors, Leukotriene B4

Eicosanoid production by inflammatory cells which resulted from infection of the peritoneal cavity of Rana catesbeiana and Bufo americanus was studied after addition of exogenous arachidonic acid and for metabolites generated in vivo. From exogenous substrate, the cells of Rana catesbeiana produced substantial amounts of 5-hydroxyeicosatetraenoic acid, leukotriene B4, the non-enzymatic isomers of leukotriene B4 and leukotriene C4. From endogenous substrate, 5-hydroxyeicosatetraenoic acid and leukotriene B4 were produced. Cells from Bufo americanus produced leukotriene B4 and 5-hydroxyeicosatetraenoic acid, from both exogenous and endogenous substrate. These observations of in vivo eicosanoid production confirm the participation of 5-lipoxygenase activity in the inflammatory response to infection.

Topics: Animals; Arachidonate 5-Lipoxygenase; Arachidonate Lipoxygenases; Arachidonic Acids; Bufonidae; Chromatography, High Pressure Liquid; Inflammation; Leukotriene B4; Peritonitis; Rana catesbeiana; SRS-A

The mechanism of the anti-inflammatory effect of proglumetacin maleate, a novel indomethacin derivative, was examined in vivo in an allergic air pouch inflammation model in rats. Proglumetacin maleate did not affect the volume of pouch exudate 6 h after immunological challenge, irrespective of whether it was administered orally or locally, but it caused dose-dependent inhibition 24 h after challenge. It also caused dose-dependent reduction of leukocyte migration into the pouch exudate both 6 and 24 h after challenge. It markedly decreased the prostaglandin E2 content of the pouch exudate, but tended to increase the leukotriene B4 content. The main metabolites of proglumetacin maleate, desproglumideproglumetacin maleate and indomethacin, had effects similar to those of proglumetacin maleate on these four parameters on an equimolar dose basis. Unlike these three drugs, dexamethasone decreased the leukotriene B4 content of the pouch exudate. These results suggest that the action of proglumetacin maleate is qualitatively the same as that of indomethacin in vivo; that is, it inhibits cyclo-oxygenase in inflammatory sites.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents, Non-Steroidal; Dexamethasone; Dinoprostone; Exudates and Transudates; Hypersensitivity; Indoleacetic Acids; Indomethacin; Inflammation; Injections, Subcutaneous; Leukotriene B4; Male; Prostaglandins E; Rats; Rats, Inbred Strains

The quantity of leukotrienes produced in an inflammation model, the stimulated mouse peritoneum, was affected by dietary manipulation of tissue arachidonic acid, the immediate leukotriene (LT) precursor. Fifty ng of LTE4 was synthesized (after injection of zymosan) by the peritoneal cavity of mice maintained on olive oil as a dietary source of unsaturated fatty acids. Animals maintained on corn oil, exhibited significantly enhanced leukotriene biosynthesis upon stimulation by zymosan. Mice fed menhaden oil, a fat source rich in n-3 fatty acids produced 50% less leukotriene E4 than animals fed olive oil. The results indicated that production of leukotrienes, potent mediators of inflammatory reactions, are affected by the type of polyunsaturated fatty acids in the diet.

Topics: Animals; Dietary Fats; Dinoprostone; Fatty Acids, Unsaturated; Inflammation; Leukotriene B4; Macrophages; Mice; Prostaglandins E; SRS-A; Zymosan

1. Acute inflammation was induced in rabbit skin by intradermal injection of arachidonic acid. 2. Inflammation was assessed by the local accumulation of intravenously-injected 125I-serum albumin (plasma extravasation) and histologically (polymorphonuclear leucocyte, PMNL infiltration). 3. Leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) were extracted from skin and fractionated using C18 mini-columns. They were quantitated by specific radioimmunoassays and authenticated by reversed-phase high performance liquid chromatography analysis. 4. Maximally elevated levels of LTB4 and PGE2 were detected in skin 5 min after arachidonic acid injection. At subsequent times the eicosanoid content of the skin decreased. 5. The decrease in the eicosanoid content of the skin was due to rapid clearance (t 1/2 approximately 5 min) via the microvasculature and not a consequence of metabolism. 6. The concentration of LTB4 and PGE2 measured in inflamed skin was sufficient to account for the plasma extravasation and PMNL infiltration induced by arachidonic acid. The model therefore is useful for evaluating the anti-inflammatory efficacy of inhibitors of arachidonic acid metabolism including 5-lipoxygenase inhibitors. 7. The consequences of the rapid clearance of LTB4 from inflammatory sites are discussed with respect to its measurement in inflammatory disease and its role as an acute inflammatory mediator.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Cell Movement; Chromatography, High Pressure Liquid; Dinoprostone; Female; Inflammation; Injections, Intradermal; Leukotriene B4; Neutrophils; Prostaglandins E; Rabbits; Radioimmunoassay; Serum Albumin, Radio-Iodinated

To determine whether supplementation with the physiological radical scavenger, vitamin E, would modulate arachidonate metabolism in human inflammation, we performed equilibrium dialysis of rectum in eight patients with active ulcerative colitis confined to the rectum. The patients, all off drug treatment, were supplemented with 1920 IU/day of alpha-tocopherol and had rectal dialysis done at entry and after three and 14 days. Luminal concentrations of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4), determined by radioimmunoassay in purified dialysates, were significantly raised compared to healthy controls. Supplements caused no change in these levels either at day 4 or 15, although serum-tocopherol showed a 3-fold increase. Also disease activity was unaffected. This failure of vitamin E supplementation to suppress the mucosal release of PGE2 and LTB4 in active inflammation does not encourage controlled trials on the effect of oral vitamin E in ulcerative colitis.

Topics: Adult; Arachidonic Acid; Arachidonic Acids; Colitis, Ulcerative; Dialysis; Diet; Dinoprostone; Female; Humans; Inflammation; Leukotriene B4; Male; Middle Aged; Prostaglandins E; Rectum; Vitamin E

Leukotrienes are potent mediators of allergy and inflammation. Polymorphonuclear granulocytes which participate in acute and chronic disease processes can be activated by immunological and nonimmunological stimuli to generate leukotrienes. It appears that on activation of the cells 5-lipoxygenase is released into the supernatant and thus may exert a potent role with regard to interdependent cellular interactions. The release of leukotriene-metabolizing enzymes (e.g., gamma-glutamyl-transpeptidase, dipeptidase) is stimulus-dependent. Polymorphonuclear granulocytes alter their release profile once the cells have been prestimulated. Thus, a precise knowledge on the leukotriene-inducing and -metabolizing enzymes is of utmost importance for future immunopharmacological interventions. It appears that the enzyme activity reflects the state of cellular activation.

Topics: Arachidonate 5-Lipoxygenase; Arachidonate Lipoxygenases; Calcimycin; Cytochrome P-450 Enzyme System; Cytochrome P450 Family 4; Dipeptidases; Enzyme Activation; Exotoxins; gamma-Glutamyltransferase; Humans; Inflammation; Leukotriene B4; Mixed Function Oxygenases; Neutrophils; SRS-A

Topics: Animals; Central Nervous System Diseases; Humans; Inflammation; Ischemia; Leukotriene B4; Shock; SRS-A

Despite the postulated role of arachidonic acid-derived metabolites in the pathophysiology of chronic inflammatory dermatoses such as psoriasis and atopic or contact dermatitis, the cutaneous effects of their chronic application have not yet been investigated. We therefore studied systematically the effects of chronic intracutaneous administration of arachidonic acid, prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and 12-hydroxyeicosatetraenoic acid (12-HETE) in guinea pigs, and describe previously unrecognized findings partly different from those reported in the past for short-term or topical application of these inflammatory mediators. Leukotriene B4 and 12-HETE led to massive histologic changes characteristic of leukocytoclastic vasculitis. These changes could be prevented by concomitant PGE2 administration. In epidermis, LTB4 and 12-HETE caused some spongiosis as well as hyperplasia and increased tritiated thymidine autoradiographic labeling index. Arachidonic acid and PGE2 alone had little effect. These data suggest that in addition to other inflammatory or hyperproliferative dermatoses, arachidonic acid metabolites formed via lipoxygenase pathways could play a major role in leukocytoclastic vasculitis, whereas PGs could exert a tissue-protective effect.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Animals; Arachidonic Acid; Arachidonic Acids; Dinoprostone; Epidermis; Female; Guinea Pigs; Hydroxyeicosatetraenoic Acids; Inflammation; Injections; Leukotriene B4; Prostaglandins E; Skin; Vasculitis

Monosodium urate (MSU) and calcium pyrophosphate dihydrate (CPPD) crystals initiated acute inflammatory reactions characterized by increased plasma extravasation and polymorphonuclear leukocyte (PMNL) accumulation in the rat subcutaneous air-pouch. Pretreatment of rats with colchicine (1 mg kg-1, s.c.) inhibited PMNL accumulation induced by either crystal type but had a greater inhibitory effect on MSU-induced plasma extravasation compared with that induced by CPPD crystals. Colchicine (1 mg kg-1, s.c.) did not reduce histamine-induced plasma extravasation in the air-pouch. The lipoxygenase product of arachidonic acid metabolism, leukotriene B4 (LTB4), was detected in MSU-induced exudates but not in CPPD-induced exudates. Pretreatment of rats with colchicine (1 mg kg-1, s.c.) inhibited LTB4 production in MSU-induced exudates.

Topics: Animals; Anti-Inflammatory Agents; Calcium Pyrophosphate; Colchicine; Diphosphates; Disease Models, Animal; Inflammation; Leukotriene B4; Male; Neutrophils; Rats; Rats, Inbred Strains; Uric Acid

Rat leukocytes from inflammatory peritoneal exudates respond in vitro to a variety of chemotactic and phagocytic stimuli by releasing both elastase and cathepsin G neutral proteinase enzyme activities. PAF, FMLP, and PMA stimulated a rapid, cytochalasin B-dependent, dose-related release of both enzymes; however, leukotriene B4 was inactive. It was not possible to measure the activity of zymosan-activated serum on these cells as rat serum contains high levels of proteinase inhibitors. The calcium ionophore A23187 stimulated a dose-related, time-dependent, cytochalasin B-independent enzyme release. Concanavalin A stimulated a weak, nondose-related release of enzyme activity. Zymosan and serum-coated zymosan stimulated enzyme secretion which was markedly inhibited by the presence of cytochalasin B. These data indicate that release of azurophillic granule neutral proteinases from rat inflammatory leukocytes can be detected and quantitated in vitro. This model could provide a test system for monitoring the pattern and specificity of enzyme release from azurophil granules. The ability of a variety of stimuli to induce proteolytic enzyme release from inflammatory neutrophils may be of considerable relevance to chronic inflammatory diseases.

Topics: Animals; Calcimycin; Cathepsin G; Cathepsins; Cytoplasmic Granules; Dose-Response Relationship, Drug; Inflammation; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Pancreatic Elastase; Peritoneal Cavity; Platelet Activating Factor; Rats; Rats, Inbred Strains; Serine Endopeptidases

Leukotrienes are synthesised from arachidonic acid via the 5-lipoxygenase pathway in neutrophils, eosinophils, monocytes/macrophages, basophils and certain mast cell populations. Their synthesis is closely regulated by several known factors and the cells which contain 5-lipoxygenase do not all possess the capability to synthesise all of the leukotrienes. Neutrophils produce leukotriene B4, which attracts other neutrophils, whereas the leukotriene C4, produced by eosinophils, increases the contractile activity of smooth muscle. Monocytes/macrophages are able to produce both of these leukotrienes. Receptor sites for leukotriene B4 have been identified on monocytes and neutrophils and receptors for leukotriene D4, a cleavage product of leukotriene C4, have been defined in pulmonary tissue. In animals, sulphidopeptide leukotrienes have been shown to cause potent vasoconstriction resulting in increased blood pressure and increased vascular permeability leading to hypovolaemia. These leukotrienes also depress renal (in animals) and pulmonary (in animals and humans) function, the latter probably as a result of effects on peripheral rather than central airways. In patients with mild asthma, however, there is no differential activity of this type. The sulphidopeptide leukotrienes caused wheal and flare when administered intradermally in healthy volunteers, which was of considerably longer duration than that induced by prostaglandin D2. Conversely, leukotriene B4 caused accumulation of neutrophils in the absence of wheal and flare. Studies into the effects of dietary fish oil showed that 2 constituents, docosahexanoic acid and eicosapentaenoic acid (EPA), inhibit the conversion of arachidonic acid by cyclo-oxygenase, but not by 5-lipoxygenase. Furthermore, 5-lipoxygenase converts EPA to a pentene series of leukotrienes and the sulphidopeptide derivatives possess similar activity to their tetrameric counterparts.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acids; Fish Oils; Hemodynamics; Humans; Inflammation; Kidney; Leukotriene B4; Lung; Skin; SRS-A

Ebselen is a novel organo-selenium compound which catalytically inactivates peroxides in vitro in a manner similar to that of glutathione peroxidase (GSH-Px). In addition, ebselen also inactivates leukotriene B4 (LTB4) generated by pig leukocytes in vitro by isomerizing this eicosanoid to its biologically inactive 6-trans isomer. In vivo, ebselen is a weak oral inhibitor of carrageenan paw oedema and adjuvant arthritis in the rat, differentiating it from classical NSAIDs such as indomethacin and diclofenac. In contrast, oral ebselen, like (intra-articular) catalase, is an effective inhibitor of monoarthritis induced in mice with amidated glucose oxidase (aGO) and dose-dependently inhibits cobra-venom-factor-induced paw oedema in rats. Indomethacin and piroxicam are weakly active or ineffective in these models. The data indicate that ebselen is likely to be useful in the therapy of inflammatory conditions in which reactive oxygen species, such as peroxides, play an aetiological role.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Azoles; Edema; Female; Indomethacin; Inflammation; Isoindoles; Leukotriene B4; Male; Organoselenium Compounds; Peroxides; Piroxicam; Rats; Rats, Inbred Strains; Selenium

Monocytes were stimulated to increase their cell surface quantity of leukocyte adhesion proteins p150,95 and Mac-1 by the chemoattractant formyl-methionyl-leucyl-phenylalanine, or other mediators such as platelet-derived growth factor, tumor necrosis factor, C5a, and leukotriene B4. Dose-response curves indicated variations in the sensitivity of monocytes and granulocytes to these mediators. These increases were independent of protein synthesis and half-maximal at 2 min. Human alveolar and murine peritoneal macrophages, cells that had previously diapedised, could not be induced to upregulate Mac-1 or p150,95. Detergent permeabilization studies in monocytes indicated that these proteins were stored in internal latent pools, which were reduced upon stimulation. Electron microscopy utilizing rabbit antiserum against p150,95 revealed these proteins on the plasma membrane, and in intracellular vesicles and peroxidase negative granules. Together with other functional studies, these findings suggest that the mobilization of Mac-1 and p150,95 from an intracellular compartment to the plasma membrane regulates the monocyte's ability to adhere and diapedese.

Topics: Animals; Antigens, Surface; Cell Adhesion; Cell Adhesion Molecules; Cell Compartmentation; Cell Membrane; Complement C5; Complement C5a; Glycoproteins; Granulocytes; Humans; Inflammation; Intracellular Membranes; Leukotriene B4; Macrophage-1 Antigen; Macrophages; Membrane Proteins; Mice; Molecular Weight; Monocytes; N-Formylmethionine Leucyl-Phenylalanine; Platelet-Derived Growth Factor; Receptors, Cell Surface; Tumor Necrosis Factor-alpha

An equine model of acute non-immune inflammation has been developed to facilitate studies of the inflammatory process and the actions of novel anti-inflammatory drugs. Five polyester sponge strips soaked in sterile 2% carrageenin solution were placed in subcutaneous pouches prepared under local anaesthesia in the necks of conscious ponies. Serial removal of the strips and harvesting of the exudate enabled studies to be made of the cellular, biochemical and mediator aspects of the localised, acute inflammation, and the heat generated by the lesion was monitored by infra-red thermometry. Maximal concentrations of the eicosanoids 6-keto-prostaglandin F1 alpha, thromboxane B2 and leukotriene B4 occurred at 9 h, whereas leukocyte numbers, lactate dehydrogenase (LDH) and total protein concentrations were greatest at 24 h. Lesional skin temperature was increased by approximately 4 degrees C throughout the 24 h period. The novel anti-inflammatory agent BW540C, administered orally at a dose-rate of 20 mg/kg, did not affect leukocyte infiltration or the concentrations of protein, LDH and eicosanoids in exudate but serum thromboxane B2 levels were reduced. Skin temperature rises were greater in drug-treated animals. It is concluded that higher doses of BW540C will be required for a clinically useful anti-inflammatory action in horses.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Disease Models, Animal; Exudates and Transudates; Female; Horse Diseases; Horses; Inflammation; L-Lactate Dehydrogenase; Leukocyte Count; Leukotriene B4; Proteins; Pyrazoles; Skin Temperature; Thromboxane B2

Topics: Animals; Arachidonic Acids; Humans; Inflammation; Leukotriene B4; Prostaglandins; Thrombosis

Fifteen timed biopsies of human skin were performed after application of 100 nanograms of leukotriene B4 in a Finnchamber for six hours. The number of inflammatory cells were counted per high power perivascular field and compared to three control biopsies. At 24 hours a peak of neutrophiles was observed and subsequently lymphocytes predominated. Eosinophils were never prominent. This pattern of successive cell populations has been described in inflammatory and whealing skin disease.

Topics: Administration, Topical; Biopsy; Eosinophils; Humans; Inflammation; Leukocyte Count; Leukotriene B4; Lymphocytes; Neutrophils; Skin; Time Factors

We investigated the role of various E. coli strains that expressed different adhesins and/or generated haemolysin with regard to the induction of inflammatory mediators, e.g. histamine release from rat mast cells as well as the chemiluminescence response and the release of lipoxygenase transformation products from human polymorphonuclear neutrophils. Our data show that the degree of haemagglutination did not parallel the induction of the chemiluminescence response. Haemolysin-negative bacteria with different adhesins induced more 5-hydroxyeicosatetraenoic acid as compared to haemolysin-positive bacteria, which generated more leukotriene B4 as compared to 5-hydroxyeicosatetraenoic acid. Among the leukotrienes, more leukotriene B4 as compared to leukotriene C4 was released from peripheral leucocytes. Studies with rat mast cells showed that histamine release was dependent on the haemolysin activity expressed by washed bacteria or present within the bacterial culture supernatant. Histamine release was markedly diminished when haemolysin activity decayed. Several haemolysin-negative bacteria with defined adhesins also released histamine, suggesting that, in addition to haemolysin, other factors contribute to mediator release. Thus, various properties of bacteria (e.g. adhesins, haemolysin) may participate to varying degrees in the induction of inflammatory mediators, e.g. oxygen radicals, lipoxygenase transformation products, leucotrienes and histamine.

Topics: Adhesins, Escherichia coli; Animals; Bacterial Proteins; Escherichia coli; Hemagglutination; Hemolysin Proteins; Histamine Release; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; Luminescent Measurements; Mast Cells; Neutrophils; Rats; SRS-A

Topics: Analgesics; Animals; Anti-Inflammatory Agents; Arachidonic Acid; Arachidonic Acids; Bradykinin; Brain Chemistry; Chemistry; Flurbiprofen; History, 20th Century; Humans; Inflammation; Leukotriene B4; Neurotransmitter Agents; Pain; Propionates; Research; SRS-A

Arachidonic acid undergoes two metabolic pathways in leukocytes. The first, catalysis by prostaglandin cyclo-oxygenase, yields the prostaglandin endoperoxides G2 and H2 and thromboxane A2, which induce rapid irreversible aggregation of human platelets and are potent inductors of smooth muscle contraction. The second pathway, catalysis by lipoxygenase, yields various hydroperoxy acids. In platelets, 12-hydroperoxyeicosatetraenoic acid is the predominant product; in polymorphonuclear leukocytes, 5-hydroperoxyeicosatetraenoic acid is formed. These are primarily reduced to 12-hydroxyeicosatetraenoic acid and 5-hydroxyeicosatetraenoic acid. 5-Hydroperoxyeicosatetraenoic acid may also be dehydrated to leukotriene A4. Enzymatic hydrolysis of leukotriene A4 yield leukotriene B4, a potent mediator of leukocyte function. Prostaglandins, thromboxanes, and some hydroxyeicosatetraenoic acids exert chemotactic effects on polymorphonuclear leukocytes. In this respect, leukotriene B4 is the most active compound derived from arachidonic acid. In vivo, adherence of leukocytes to the endothelium of microvessels near inflammatory areas and the sticking phenomenon of these cells are the initial hallmarks of an inflammatory response. In vitro, these responses seem to correspond with leukocyte aggregation and adherence. Leukotriene A4 may also react to form leukotriene C4 (a natural component of slow-reacting substance of anaphylaxis), leukotriene D4, leukotriene E4, and the 11-trans-isomers. All three leukotrienes are virtually unable to induce chemotaxis, enzyme release, or leukocyte aggregation, but they possess biologic properties previously attributed to slow-reacting substances, such as a potent effect on smooth muscle in the peripheral airway and an ability to markedly increase macromolecular permeability in venules. In addition to prolonging bleeding time and causing gastric ulcers, aspirin and other nonsteroidal anti-inflammatory drugs can trigger or aggravate an asthmatic attack. Aspirin can also trigger or aggravate urticaria, probably as a direct effect of thioether leukotrienes rather than from antibody mediation. Many nonsteroidal anti-inflammatory drugs increase formation of slow-reacting substance-A after challenge with allergen, perhaps by inhibiting cyclo-oxygenase, thereby releasing more arachidonic acid for metabolism by lipoxygenase. Alternatively, certain prostaglandins inhibit liberation of arachidonic acid from phospholipids; inhibiting their formation c

Topics: Animals; Anti-Inflammatory Agents; Arachidonic Acid; Arachidonic Acids; Autacoids; Guinea Pigs; Humans; Inflammation; Leukotriene A4; Leukotriene B4; Prostaglandins; SRS-A; Thromboxanes

The metabolism of leukotrienes (LTs) in the cell-containing inflammatory exudate of rat pleurisy was studied in vitro. The exudates of both nonallergic carrageenin-induced pleurisy and IgG immune complex-mediated pleurisy converted 3H-LTB4 to 20-OH LTB4, but virtually did not metabolized 3H-LTC4 or 3H-LTE4 up to 2 hrs. 3H-LTD4 was changed to LTC4 by the exudate of non-allergic pleurisy, whereas 3H-LTD4 was metabolized to LTE4 by that of allergic pleurisy. Reflecting on the different metabolism, the gamma-glutamyl transpeptidase activity in the exudate of carrageenin-induced pleurisy was significantly higher than that in IgG immune complex mediated pleurisy. The enzyme activity was not derived from the blood itself, but from the infiltrated polymorphonuclear leukocytes. The activity of the cell homogenate in both exudates was not significantly different. Thus, it could be concluded that the difference in the metabolism of LTD4 between the nonallergic and allergic pleural exudates in vitro was mainly attributable to the enhanced activity of the gamma-glutamyl transpeptidase released in the exudate.

Topics: Animals; Antigen-Antibody Complex; Carrageenan; gamma-Glutamyltransferase; Immunoglobulin G; In Vitro Techniques; Inflammation; Kinetics; Leukotriene B4; Male; Pleurisy; Rats; Rats, Inbred Strains; SRS-A

Fibrin formation and turnover are intimately associated with inflammation and wound healing. To explore whether fibrin(ogen)-derived peptides exert direct effects upon cells involved in inflammation and tissue repair we examined the capacity of human fibrinopeptide B (hFpB), a thrombin-derived proteolytic cleavage product of the fibrinogen B beta-chain, to stimulate neutrophils (PMN), monocytes, and fibroblasts. hFpB caused directed cell migration of PMN and fibroblasts that was optimal at approximately 10(-8) M. This chemotactic activity was blocked by preincubating hFpB with antiserum to hFpB. hFpB was not chemotactic for monocytes. The chemotactic potency of hFpB for PMN was equivalent to that of anaphylatoxin from the fifth component of human complement (C5a), leukotriene B4 (LTB4), and formyl-methionyl-leucyl-phenylalanine (fMLP), and for fibroblasts its chemotactic activity was comparable to that of platelet-derived growth factor. hFpB did not interact with PMN receptors for C5a, LTB4, or fMLP as (a) desensitization with 10(-7) M hFpB abolished chemotaxis to hFpB but had no effect upon chemotaxis to C5a, LTB4, or fMLP and (b) induction of chemotactic responses to fMLP and LTB4 in neutrophilic leukemic cells (HL-60 cells) by incubation with dimethylsulfoxide did not extend to hFpB. Like fMLP, hFpB caused a rapid, dose-dependent increase in PMN cytoskeletal associated actin, but unlike fMLP, hFpB did not cause PMN aggregation, release of lysosomal enzymes (lysozyme and beta-glucuronidase), or the production of superoxide anion. These results suggest that hFpB may have a role in recruiting PMN and fibroblasts at sites of fibrin deposition and turnover. The capacity of hFpB to cause PMN chemotaxis without causing concurrent release of lysosomal enzymes or the production of superoxide anion is further evidence for the complexity of PMN responses to chemotactic agents.

Topics: Actins; Cell Aggregation; Cell Membrane; Cells, Cultured; Chemotaxis, Leukocyte; Complement C5; Complement C5a; Dimethyl Sulfoxide; Fibrinogen; Fibrinopeptide A; Fibroblasts; Glucuronidase; Humans; Inflammation; Leukotriene B4; Lysosomes; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Superoxides

Products derived from arachidonic acid (AA) via both the cyclo-oxygenase and lipoxygenase pathways play a role in inflammation: prostaglandins (PGs), particularly PGE2, contribute to the formation of oedema, erythema and hyperalgesia whereas leukotriene B4 (LTB4), a product of the 5' lipoxygenase, may modulate the recruitment of leukocytes. We have previously reported that supplementation of a standard rat diet with eicosapentaenoic acid (EPA) caused a significant increase in the formation of LTB5, which is less active biologically than LTB4, and a decrease in the synthesis of LTB4 by stimulated leukocytes. Now we have assessed the effects of administration of highly purified EPA ethyl ester (79% pure), in two models of acute inflammation. Supplementation of a standard rat diet with 240 mg/kg/day EPA for 4 weeks significantly decreased the concentration of PGE2 and TXB2 in inflammatory exudate derived from implantation of carrageenin impregnated sponges: neither the concentration of LTB4 nor the cell number were reduced significantly. Triene prostaglandins were not detected in the exudate, however, significant levels of LTB5 were present. In the second model, oedema induced by injection of carrageenin into rat paws was significantly reduced in animals fed an EPA-rich diet. Supplementation of the diet with EPA could, by mainly reducing the synthesis of prostaglandins, offer a novel and non-toxic approach to the modulation of an inflammatory response.

Topics: Animals; Diet; Eicosapentaenoic Acid; Exudates and Transudates; Inflammation; Leukocyte Count; Leukotriene B4; Prostaglandins; Rats; Thromboxanes

Bromelain, a proteolytic enzyme extracted from pineapple plants, was investigated for its capacity to interfere with arachidonic acid metabolism, since prostaglandins and other eicosanoids are well-known to be involved in the pathogenesis of inflammatory diseases. Bromelain was tested for its ability to interfere with eicosanoids generation in vivo in two experimentally-induced inflammatory reactions in the rat. Also antiplatelet aggregation activity of bromelain was studied in ex vivo rat platelets. The results seem to indicate an interference of bromelain with arachidonic acid cascade, which, however, deserves further investigation to be better assessed.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Bromelains; Dinoprostone; Exudates and Transudates; Indomethacin; Inflammation; Leukotriene B4; Lipoxygenase; Male; Platelet Aggregation; Prostaglandins E; Rats; Rats, Inbred Strains; Thromboxane B2

Carrageenin pleurisy was induced in adrenalectomised (ADX) and sham-operated (SHO) rats. The magnitude and duration of inflammation, as estimated by fluid exudation and cell migration, was greatly increased (approximately doubled) in ADX rats compared with that in their SHO controls. The content of eicosanoids (6-keto-prostaglandin F1 alpha (6-keto-PGF 1 alpha), thromboxane B2 (TXB2), and leukotriene B4 (LTB4] in inflammatory exudates from ADX rats was significantly (2-4 fold) greater than that of their SHO controls. Resident macrophages obtained from ADX rats produced more eicosanoids per cell per unit time when stimulated in vitro with zymosan, than did cells from the SHO controls. Administration of glucocorticoids blocked the inflammatory response and reduced the release of eicosanoids both in vitro and in vivo in both groups of rats. These data are consistent with the notion that physiological amounts of glucocorticoids exert a tonic inhibitory action on phospholipase activity in normal animals and that the increased secretion of these hormones during the inflammatory response serves to check and control the development of inflammation.

Topics: 6-Ketoprostaglandin F1 alpha; Acute Disease; Adrenalectomy; Animals; Annexins; Carrageenan; Glucocorticoids; Glycoproteins; In Vitro Techniques; Inflammation; Leukotriene B4; Phospholipases A; Pleurisy; Rats; Thromboxane B2

Topics: Animals; Anti-Inflammatory Agents; Disease Models, Animal; Inflammation; Leukotriene B4; Receptors, Drug

Eicosapentaenoic acid enriched diet may reduce the severity of acute inflammatory reactions by decreasing the synthesis of dienoic prostanoids and tetraenoic leukotrienes. The findings suggest that a nutritional approach to anti-inflammatory therapy is an interesting possibility deserving further studies.

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Eicosapentaenoic Acid; Inflammation; Leukocytes; Leukotriene B4; Rats; SRS-A

Leukotriene B4 (LTB4) is a metabolite of arachidonic acid that has potent chemotactic activity for polymorphonuclear leukocytes (PMN). Pulmonary oxygen toxicity is considered to be a good model of an acute inflammatory lung injury, and an increase in the number of PMN is found in the lungs acutely injured by hyperoxia. In order to estimate the role of LTB4 responsible for this influx of PMN, we measured the LTB4 by radioimmunoassay in lung lavages of rats exposed to hyperoxia for 60 h. We found that the level of LTB4 in lung lavages in rats exposed to hyperoxia for 60 h increased significantly compared with that in normoxic control rats. At the same time, the marked increase in the number of PMN in lung lavages and the decrease in the activity of NADPH-cytochrome c reductase in lung microsomes were also observed. The administration of AA861, a 5-lipoxygenase inhibitor, reduced not only the increase in LTB4 but also the increase in the number of PMN in lung lavages of rats exposed to hyperoxia for 60 h. Furthermore, treatment with AA861 also protected the decrease in the activity of NADPH-cytochrome c reductase. The effects of AA861 on these parameters were observed in a dose-dependent fashion. In addition, there is a good correlation between the level of LTB4 and the number of PMN in the lavage of rats exposed to hyperoxia for 60 h with or without AA861 administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Benzoquinones; Female; Inflammation; Leukotriene B4; Lung; Lung Diseases; Microsomes; NADPH-Ferrihemoprotein Reductase; Neutrophils; Oxygen; Quinones; Rats; Rats, Inbred Strains

The subcutaneous sponge implant model of acute inflammation in the rat has been evaluated as a suitable test system for evaluating the potential anti-inflammatory efficacy of 5-lipoxygenase inhibitors. The inflammatory parameters measured were exudate volume and leukocyte recruitment. Specific radioimmunoassays were used to measure (1) 5-lipoxygenase (LPO) and cyclo-oxygenase (CO) activity in exudate leukocytes stimulated ex vivo with A23187, and (2) the LTB4 and PGE2 content of inflammatory exudate. The NSAIDs flurbiprofen and indomethacin inhibited cell recruitment, exudate volume and CO activity with ED50S of approximately 1 mg per kg p.o. but failed to inhibit LPO activity at 10 mg per kg p.o. Nafazatrom (Bayer 6575), quercetin and NDGA, which inhibit LPO activity in vitro, were inactive against all parameters when dosed at 100 mg per kg p.o. The "mixed inhibitors" BW755C and phenidone were approximately equipotent inhibitors of LPO activity but BW755C was 10 times more potent than phenidone against CO activity. BW755C was also greater than 10 times more potent at inhibiting cell recruitment and exudate volume than phenidone suggesting that the anti-inflammatory efficacy of the mixed inhibitors reflect their potency against CO rather than LPO activity. Time course studies demonstrated that the inhibitor effects of BW755C and phenidone on leukocyte recruitment reflected a reduction in the PGE2 but not the LTB4 content of the inflammatory exudate. Polyester sponges soaked in high concentrations of LTB4 caused only a modest (2-fold) increase in leukocyte recruitment whilst physiological levels were inactive. The results taken together suggest that CO products make a major contribution to leukocyte recruitment in this model whilst the LPO product LTB4 has little role. This model therefore is of little value for evaluating the anti-inflammatory efficacy of 5-lipoxygenase inhibitors. Moreover, the rat would appear to be unsuitable for evaluating the role of LTB4 in acute inflammation.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Acute Disease; Animals; Blood Proteins; Calcimycin; Chemotaxis, Leukocyte; Cyclooxygenase Inhibitors; Dinoprostone; Dose-Response Relationship, Drug; Flurbiprofen; Indomethacin; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Male; Prostaglandins E; Pyrazoles; Pyrazolones; Rats; Rats, Inbred Strains; Skin

Topics: Airway Resistance; Arachidonic Acids; Chemotaxis, Leukocyte; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; Leukotrienes; Lipoxygenase; Molecular Conformation; Prostaglandin-Endoperoxide Synthases; Prostaglandins; SRS-A; Terminology as Topic; Vasomotor System

The leukotrienes of white cells are powerful pharmacological mediators that are implicated in many immunological reactions. The most powerful effects (bronchoconstriction and mucus secretion) are seen in asthma. The circulatory effects are local, except perhaps in endotoxin shock. Apart from corticosteroids, there are as yet no inhibitors in use in therapeutics.

Topics: Animals; Asthma; Humans; Inflammation; Leukotriene B4; Lipoxygenase; Lung; Lymphocytes; Prostaglandin-Endoperoxide Synthases; SRS-A

Inflammatory peritoneal exudates from 11 patients with purulent peritonitis or non-perforative appendicitis were analyzed by gas chromatography mass spectrometry (GC-MS) for their content of 5S, 12R-dihydroxy-6,14-cis-8,10-trans-eicosatetraenoic acid (LTB4) and its omega-oxidized catabolite, 5S,12R,20-trihydroxy-6,8,10,14-eicosatetraenoic acid (20-OH-LTB4). Eleven samples of peritoneal exudates were examined. LTB4 and 20-OH-LTB4 were demonstrated only in the samples from patients with purulent peritonitis. LTB4 was detected in 4 samples, and 20-OH-LTB4 was detected in 6 samples by GC-MS with selected ion monitoring. In addition, a nearly full spectrum corresponding to that of synthetic 20-OH-LTB4 was obtained with 3 samples. Neither LTB4 nor 20-OH-LTB4 were detected in samples from patients with non-perforative appendicitis. LTB4 or 20-OH-LTB4 may be related to the pathophysiological mechanism of purulent inflammations.

Topics: Appendicitis; Ascitic Fluid; Gas Chromatography-Mass Spectrometry; Humans; Inflammation; Leukotriene B4; Peritonitis

Migration in vitro by blood and inflammatory neutrophils has been compared serially during an inflammatory response. Using an experimental pig model, neutrophils are isolated from the peripheral blood and from the pleural space at hourly intervals after an intrapleural challenge with zymosan activated pig serum (ZAS). Following acepromazine sedation and halothane anesthesia, blood neutrophil migration was transiently reduced. By 1 hour random and directed migration of blood neutrophils returned to normal. Directed and random migration of exudate neutrophils was markedly decreased to both a stimulus-specific (ZAS) and an unrelated (LTB4) chemoattractant. After 3 hours, migration by exudate neutrophils was similar to migration by blood neutrophils examined in parallel. These findings emphasize the importance of performing serial evaluations of cell function during an inflammatory response.

Topics: Animals; Cell Migration Inhibition; Cell Movement; Exudates and Transudates; Inflammation; Leukotriene B4; Neutrophils; Swine; Zymosan

Topics: Animals; Anti-Inflammatory Agents; Arachidonic Acid; Arachidonic Acids; Cyclooxygenase Inhibitors; Humans; Hypersensitivity; Inflammation; Leukotriene B4; Phospholipases A; Prostaglandin Endoperoxides; Prostaglandin-Endoperoxide Synthases; Prostaglandins; SRS-A; Thromboxane-A Synthase

Topics: Humans; Hypersensitivity; Inflammation; Leukotriene B4; SRS-A

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Adult; Eicosanoic Acids; Erythema; Female; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; Male; Photosensitivity Disorders; Skin; Ultraviolet Rays

The potent vasodilator calcitonin gene-related peptide (CGRP, human synthetic), when mixed with histamine and injected intradermally in the rabbit, induced a marked potentiation of local oedema. CGRP also potentiated oedema induced by other mediators of increased microvascular permeability in the rabbit; bradykinin, platelet-activating factor (Paf), C5a des Arg, N-formylmethionyl-leucyl-phenylalanine (FMLP) and leukotriene B4 (LTB4). Substance P alone, or mixtures of substance P and CGRP, failed to induce oedema in rabbit skin. In rat skin, however, substance P induced oedema and this was potentiated by CGRP. CGRP had a protracted potentiating action following intradermal injection in the rabbit. The time for half loss of activity for CGRP was 40.1 +/- 7.5 min compared to 18 +/- 1 min for prostaglandin E2 (PGE2). No loss of potentiating activity was detected after incubation of CGRP in rabbit plasma or blood for 60 min. We postulate that endogenous CGRP, if released locally from nerve endings, could have a marked enhancing effect on oedema induced by other mediators in an inflammatory reaction.

Topics: Animals; Bradykinin; Calcitonin Gene-Related Peptide; Capillary Permeability; Complement C5; Complement C5a, des-Arginine; Dinoprostone; Drug Synergism; Edema; Histamine; Inflammation; Injections, Intradermal; Leukotriene B4; Male; N-Formylmethionine Leucyl-Phenylalanine; Nerve Tissue Proteins; Platelet Activating Factor; Prostaglandins E; Rabbits; Rats; Rats, Inbred Lew; Skin; Species Specificity; Substance P

Topics: Anti-Inflammatory Agents, Non-Steroidal; Cyclooxygenase Inhibitors; Diabetic Retinopathy; Eye Burns; Glaucoma; Humans; Inflammation; Intraocular Pressure; Leukotriene B4; Ocular Physiological Phenomena; Prostaglandin-Endoperoxide Synthases; Prostaglandins; SRS-A

The leukotrienes are a family of potent mediators of hypersensitivity and inflammation. The application of sensitive and specific radioimmunoassays for leukotrienes has revealed the generation of significant quantities of several leukotrienes by leukocytes exposed to natural stimuli in the absence of exogenous arachidonic acid. The C6 peptide leukotrienes, LTC4 and LTD4, are potent vasoactive and smooth muscle contractile factors. LTB4 and other di-HETEs stimulate polymorphonuclear leukocyte function and suppress T-lymphocyte activities. The effects of LTB4 on T lymphocytes are subset-specific and include the activation of suppressor and cytotoxic T cells. Receptors for LTB4 on polymorphonuclear leukocytes are specific but exhibit considerable heterogeneity of binding affinity and may mediate different functional effects. The complexity of the pathways of generation and metabolism of leukotrienes, and of the leukotriene receptors, suggest that carefully defined systems will be needed to test the effects of pharmacological inhibitors and antagonists.

Topics: Arachidonic Acid; Arachidonic Acids; Drug Therapy; Humans; Hypersensitivity; Inflammation; Leukocytes; Leukotriene A4; Leukotriene B4; Lipoxygenase; Lymphocytes; Muscle, Smooth, Vascular; Neutrophils; Receptors, Immunologic; Receptors, Leukotriene B4; SRS-A

Variations in the magnitude of inflammatory macrophage response in vivo and macrophage chemotaxis in vitro, observed among inbred mouse strains, suggest that these traits are genetically-regulated. The development of an A X B series of recombinant inbred (RI) strains of mice derived from the C57BL/6J (B, high responder) and A/J (A, low responder) resulted in the availability of a large number of new inbred strains which express a spectrum of variations in the magnitude of these traits. These strains were used in the present study as a tool to examine the possible correlation between the phenomenon of leukocyte adherence inhibition (LAI) and those of macrophage inflammatory response in vivo and macrophage chemotaxis in vitro under the assumption the LAI requires the same cellular events as chemotaxis and that LAI resembles, grossly, the accumulation of nonadherent inflammatory cells in vivo. The typing of A X B RI strains for the traits of LAI, macrophage accumulation in vitro, and macrophage inflammatory response in vivo resulted in a correlation between the magnitude of response of those three phenomena in the total of 19 inbred strains tested, thus suggesting that the chemoattractant-induced LAI is biologically related to the events that mediate macrophage chemotaxis in vitro and the macrophage inflammatory response to sterile irritants in vivo.

Topics: Animals; Chemotaxis, Leukocyte; Guinea Pigs; Humans; Inflammation; Leukocyte Adherence Inhibition Test; Leukocytes; Leukotriene B4; Macrophages; Mice; Mice, Inbred A; Mice, Inbred C57BL; Rabbits; Spleen; Thioglycolates

Monohydroxy acids (HETEs) and leukotriene B4 (LTB4) metabolites of arachidonic acid were measured in skin of healthy volunteers after ultraviolet B irradiation, and in the uninvolved skin of psoriatics after topical dithranol application. Exudate was collected from suction bullae on control and inflamed abdominal skin, and analysed for 12-HETE and PGE2 by GC-MS and LTB4 by bioassay. 12-HETE and PGE2 were raised at 24 h but not at 72 h after u.v.B irradiation: control and 24 h values were 13.7 and 41.5 ng ml-1 (P less than 0.05, n = 6) for 12-HETE respectively, and 4.5 and 30.2 ng ml-1 (P less than 0.01, n = 6) for PGE2. Dithranol application raised PGE2 levels from 23.1 ng ml-1 in control exudate to 62 ng ml-1 (P less than 0.01, n = 6) at 24 h before declining to base levels at 72 h. However, 12-HETE was raised at 72 h (200 ng ml-1, P less than 0.01, n = 5) but not at 24 h (104 ng ml-1) compared to control levels (50 ng ml-1, n = 5). The levels of the LTB4 were low (less than 100 pg ml-1), and no significant increases were observed. Arachidonic acid in inflamed skin can be metabolised by the cyclo-oxygenase and lipoxygenase pathway. It is probable that the lipoxygenase product 12-HETE is involved in these inflammatory reactions.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Adult; Anthralin; Arachidonic Acid; Arachidonic Acids; Dinoprostone; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene B4; Lipoxygenase; Male; Prostaglandins E; Psoriasis; Radiation Injuries; Skin; Time Factors; Ultraviolet Rays

The glutathione-containing leukotriene C4 (LTC4) is a major mediator of smooth muscle contraction and is released by mast cells when antigen interacts with cell-bound IgE. Antigen-stimulated mast cells undergo phospholipase activation. We report a pathway of LTC4 production by mast cells that does not require phospholipase activation but depends on the interaction of activated neutrophils with unstimulated mast cells, using as an intermediate extracellular leukotriene A4 (LTA4). The epoxide LTA4 is released by neutrophils and, together with leukotriene B4 and 5-hydroxyeicosatetraenoic acid, constitutes the major lipoxygenase metabolites found in supernatants of stimulated neutrophils. Five minutes after activation of neutrophils by calcium ionophore A23187 we measured 136 pmol of extracellular LTA4 per 10(7) neutrophils (range 40-300, n = 7) by trapping the epoxide with alcohols. Therefore, we conclude that LTA4 is not just an intracellular leukotriene precursor but is released as a lipoxygenase metabolite. LTA4 is known to be stabilized by albumin and is efficiently converted by mast cells into LTC4 even at low LTA4 concentrations. The LTA4 complexed to albumin is converted into LTC4 rapidly and completely within 10-15 min. More than 50% of the LTA4 presented to mast cells is metabolized to LTC4 at concentrations of LTA4 between 0.2 and 2 nmol of LTA4 per 10(7) mast cells. This observation establishes a potential physiologic role for extracellular LTA4. Therefore, interactions between various cell types that release or utilize LTA4 may provide an important metabolic pathway for the production of leukotrienes.

Topics: Animals; Arachidonic Acids; Calcimycin; Humans; Inflammation; Leukotriene A4; Leukotriene B4; Lipoxygenase; Mast Cells; Mice; Neutrophils; Phospholipases; SRS-A

Topics: Animals; Blood Platelets; Dietary Fats; Fatty Acids, Essential; Humans; Inflammation; Leukotriene B4; Models, Chemical; Prostaglandin-Endoperoxide Synthases; Prostaglandins; SRS-A; Substrate Specificity; Thrombosis

Streptococcal cell wall fragments, suspended in phosphate-buffered saline, were injected into a preformed subcutaneous air pouch in rats. The advantage of the air pouch model is the capacity for quantitation of exudative, cellular, and proliferative responses and soluble mediators. Accumulation of pouch fluid containing many leukocytes occurred during the first 3 days. Granulation tissue separable from the surrounding subcutaneous tissue developed by 6 days. Immunofluorescence and immunoperoxidase staining showed the presence of cell walls in inflammatory cells both in pouch fluid and in pouch tissue. Histologic features of this inflammation included an acute exudative phase with a predominantly neutrophil infiltration followed by a chronic phase characterized by fibroblast proliferation, formation of blood vessels, and infiltration with mononuclear cells. The lining of the pouch before injection of cell wall developed morphologic features of synovial membrane, which became more evident during the chronic phase of induced inflammation. Outbred Sprague-Dawley and inbred Lewis rats developed more pouch fluid, cell numbers in the pouch fluid, and granulation tissue than inbred Buffalo rats. The arachidonic acid metabolites, prostaglandin E2 and leukotriene B4, were measured in the pouch fluid, and more of each was produced in the Lewis than in the Buffalo strain. These measurements of inflammation are consistent with the relative susceptibility of these strains to cell-wall-induced arthritis. This model of inflammation can be used in the examination of the regulatory mechanisms of evolving chronic inflammation.

Topics: Animals; Cell Wall; Dinoprostone; Disease Models, Animal; Inflammation; Leukotriene B4; Prostaglandins E; Rats; Rats, Inbred BUF; Rats, Inbred Lew; Species Specificity; Streptococcus pyogenes; Time Factors

Topics: Dietary Fats; Eicosapentaenoic Acid; Epoprostenol; Humans; Inflammation; Leukocytes; Leukotriene B4; Myocardial Infarction; Thrombosis; Thromboxane A2

Intraperitoneal injection of zymosan in mice induced rapid extravasation and accumulation of plasma protein in the peritoneal cavity. Neutrophils began to appear in the peritoneal cavity after a lag period of approximately 3 hours. The injected mice exhibited a pain response (writhing) during the first 30 minutes after injection, but writhing ceased before protein or cell accumulation had reached maximum levels. The injection of zymosan induced synthesis of PGE2 (measured by RIA) which reached maximum levels at 30 minutes, then declined slowly. Peptido-leukotriene levels (detected by bioassay, RIA and HPLC) increased rapidly after injection, reached a peak within an hour of injection and declined to undetectable levels within 4 hours. The early peptido-LT was predominantly LTC4, while later, LTE4 was the major component. LTD4 levels remained low throughout and no LTB4 was detected at any time. Indomethacin treatment elevated levels of peptido-LTs, reduced PGE2 levels and inhibited writhing. Phenidone reduced peptido-LT levels. In vitro studies demonstrated that zymosan stimulates LTC4 synthesis by peritoneal cells whereas LTE4, LTD4, LTB4 or monoHETES were not detectable (using HPLC methods). The source of enzymes responsible for the in vivo metabolism of LTC4 to LTD4 and LTE4 could not be identified.

Topics: Animals; Arachidonate Lipoxygenases; Cell Aggregation; Dinoprostone; In Vitro Techniques; Indomethacin; Inflammation; Injections, Intraperitoneal; Leukotriene B4; Leukotriene E4; Lipoxygenase; Male; Mice; Mice, Inbred Strains; Pain; Prostaglandins E; Proteins; SRS-A; Zymosan

Topics: Humans; Inflammation; Leukocytes; Leukotriene B4; Prostaglandins

The concentration of LTB4 in in vitro incubations of leukocytes and in experimentally-induced inflammatory exudate can be determined reliably by direct RIA; i.e., extraction and chromatography of samples prior to RIA are not mandatory. It is probable that the RIA for LTB4 is also suitable for monitoring the levels of LTB4 in clinical samples (e.g., synovial fluid, blister fluid from involved psoriatic skin).

Topics: Animals; Humans; Inflammation; Leukotriene B4; Neutrophils; Radioimmunoassay; Serum Albumin, Bovine

Topics: 5,8,11,14-Eicosatetraynoic Acid; Anti-Inflammatory Agents; Antigen-Antibody Complex; Arachidonic Acids; Aspirin; Humans; Indomethacin; Inflammation; Leukotriene B4; Muscle, Smooth; Oxidation-Reduction; SRS-A

Leukotrienes (LTs) have potent biologic properties, suggesting a role in human disease. LTB4 release has been detected in inflammatory exudates in the rat. LTC4 release has been detected after antigen challenge of lung tissue in vitro and in tear fluid in man in vivo. There is some evidence to suggest that LTB4 is a mediator of ulcerative colitis in man and considerable evidence to suggest that LTB4, LTC4, and LTD4 may be involved in the pathogenesis of psoriasis.

Topics: Allergens; Colitis, Ulcerative; Humans; Inflammation; Leukotriene B4; Neutrophils; Psoriasis; Skin; SRS-A

Desensitization of the neutrophil inflammatory response to intracutaneous injection of chemotaxins and endotoxin was studied in rabbits. When restimulated 6 hr later with the same agent, inflammatory lesions initiated with platelet-activating factor (PAF), leukotriene B4 (LTB4), or endotoxin supported a diminished influx of neutrophils compared with responses in normal skin. In contrast, repeated stimulation of lesions with alpha-casein failed to lead to desensitization. The specificity of desensitization was investigated, and it was found that lesions initiated with formylmethionyl-leucyl-phenylalanine (FMLP) supported a normal response when restimulated with PAF, alpha-casein, or endotoxin. Initiation of lesions with LTB4, however, diminished the subsequent response to zymosan-activated plasma and PAF, but not endotoxin, alpha-casein, or FMLP. This result indicates that LTB4 is not a final common mediator of neutrophil infiltration of acute inflammatory lesions. Desensitization was detected irrespective of the concentration of chemotaxin used to investigate the response. Repeated stimulation of lesions with FMLP abolished the accumulation of neutrophils after the final stimulus, indicating that complete desensitization can occur and the presence of a chemotaxin within an inflammatory lesion is not sufficient stimulus for neutrophil infiltration of the site to proceed. Lesions initiated with endotoxin supported comparable responses when restimulated with a mixture of FMLP and endotoxin or FMLP alone, despite 93% inhibition of the response to restimulation with endotoxin alone. This indicates that a cell-directed inhibitor of neutrophil migration, such as lipomodulin or neutrophil-immobilizing factor, does not produce the diminished responses in desensitized lesions. It is proposed that desensitization occurs due to down-regulation of a receptor-coupled pathway that permits or facilitates neutrophil extravasation in acute inflammatory lesions. The chemotaxin receptors regulating neutrophil extravasation are probably located on endothelial cells of post-capillary venules.

Topics: Acute Disease; Animals; Caseins; Chemotactic Factors; Desensitization, Immunologic; Dose-Response Relationship, Immunologic; Endotoxins; Female; Inflammation; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Platelet Activating Factor; Rabbits; Zymosan

Topics: Animals; Anti-Inflammatory Agents; Dinoprostone; Disease Models, Animal; Inflammation; Leukocyte Count; Leukotriene B4; Propionates; Prostaglandins E; Rats; Thromboxane B2

Topics: Animals; Arachidonic Acids; Aspirin; Burns; Cell Membrane Permeability; Dinoprostone; Eosinophils; Free Radicals; Humans; Inflammation; Leukotriene B4; Neutrophils; Prostaglandins; Prostaglandins E; Receptors, Immunologic; Receptors, Leukotriene B4; Skin; SRS-A; Steroids; Thromboxane-A Synthase

Leukocyte numbers and Leukotriene B4- (LTB4-) and LTC4-immunoreactivity were measured in inflammatory exudates obtained from sponges impregnated with several irritants implanted subcutaneously in the rat. Sponges containing 1% uric acid, carrageenan or zymosan were implanted for 5h and compared to saline sponges. Increases in leukocyte numbers and LTB4-immunoreactivity were found in the presence of irritants, the highest concentrations being observed in the presence of zymosan. The presence of LTB4 was confirmed by liquid chromatographic (HPLC) analysis. A time course study was carried out with zymosan-impregnated sponges and the maximal rate of leukocyte infiltration was found to coincide with the maximal levels of LTB4-immunoreactivity. The LTC4-immunoreactivity was low and following analysis by HPLC was concluded to be unrelated to leukotrienes. The levels of LTB4-immunoreactivity, but not the numbers of leukocytes, were elevated compared to corresponding controls in sponges containing 0.01% ionophore A23187 (untreated rats) or in sponges containing zymosan (rats pretreated with indomethacin; 3 and 10 mg/kg p.o.). Impregnation of sponges with 3 X 10(-6)M LTB4 but not 3 X 10(-5) and 3 X 10(-7)M LTB4 induced a significant leukocyte migration. It was concluded that LTB4 can induce leukocyte migration into sponge exudates in the rat but that measurements of LTB4 in such exudates can not be correlated with the degree of leukocyte infiltration.

Topics: Animals; Antibody Specificity; Calcimycin; Carrageenan; Chromatography, High Pressure Liquid; Exudates and Transudates; Indomethacin; Inflammation; Leukocyte Count; Leukotriene B4; Neutrophils; Rats; SRS-A; Zymosan

The biotransformation of arachidonic acid leads to two important groups of inflammatory mediators, the leukotrienes and the prostaglandins. Hyperalgesic effects have been demonstrated for prostaglandins in a variety of animal models but the effects of leukotrienes on inflammatory pain are less well documented. Using the isolated rabbit ear model of algesia we have shown that perfusion of the ear with the leukotrienes B4, C4 and D4 (10(-8)-10(-7) M) causes a reversible, dose- and time-dependent reduction of the reflex fall in systemic blood pressure and the "head flick" response induced by injection of bradykinin (400 ng), without affecting similar responses induced by the neurotransmitter acetylcholine. The antagonistic effect of leukotrienes on the algesic action of bradykinin could be reversed by the leukotriene antagonist FPL55712 (2 micrograms/ml). This result implies that the leukotrienes may have a desensitizing effect on the nociceptor during an inflammatory response in contrast to the pain threshold-lowering action of the E- and I-type prostaglandins.

Topics: Acetylcholine; Animals; Blood Pressure; Bradykinin; Chromones; Inflammation; Leukotriene B4; Male; Nociceptors; Rabbits; SRS-A

Topics: Animals; Carrageenan; Disease Models, Animal; Exudates and Transudates; Horse Diseases; Horses; Inflammation; Leukotriene B4; Neutrophils; Rats

Leukotriene B4 (LTB4) is a potent mediator of inflammation. Recently, reports have indicated that LTB4 may affect lymphocyte function in vitro. Therefore, we examined the effect of LTB4 following intrapleural injection to determine if LTB4, released at an inflammatory site, would affect rat mononuclear cell function. LTB4 appeared to have little effect on mitogen-induced lymphocyte transformation nor was any direct mitogenic effect observed at concentrations ranging from 10(-6)-10(-12) molar. However, a marked inhibition of a one-way mixed lymphocyte reaction was observed upon in vitro culturing of lymphocytes from animals examined 72-96 hr after a single intrapleural injection of LTB4. We conclude that LTB4 released at inflammatory sites may play a role in modulating immune function but it appears not to be a direct effect but rather, although the evidence is circumstantial, an indirect effect.

Topics: Animals; Immunity, Cellular; Inflammation; Leukotriene B4; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Male; Mitogens; Neutrophils; Rats; Spleen; T-Lymphocytes, Regulatory; Time Factors

Topics: Aspirin; Cell Movement; Humans; In Vitro Techniques; Inflammation; Leukocytes; Leukotriene B4

The study concerned the effect of arachidonic acid metabolites on the inflammatory reaction in granulation tissue of open wounds in rats. Metabolites or inhibitors were applied in a wound chamber attached to circular, open, full-thickness skin wounds 5 days post-wounding. The adjacent wound served as control. Blood flow, albumin extravasation and accumulation of polymorphonuclear leucocytes (PMNLs) were measured in the granulation tissue. Prostaglandin E2 (PGE2 5.7 microM) increased blood flow and albumin extravasation by 95 and 16%, respectively, without affecting PMNLs. Leukotriene B4 (LTB4 2.7 microM) increased PMNL accumulation by 142% without altering albumin extravasation. Indomethacin (28 microM, repeatedly) did not affect blood flow or albumin extravasation, but increased PMNL accumulation by 21%. Methylprednisolone (3.3 mM, repeatedly) reduced blood flow and albumin extravasation by 29 and 31%, respectively, without influencing PMNLs. The granulation tissue obviously responds to exogenous PGE2 and LTB4. Endogenous arachidonic acid metabolites seem to play only a minor role in the inflammatory process in this model.

Topics: Animals; Arachidonic Acids; Biotransformation; Dinoprostone; Granulation Tissue; Indomethacin; Inflammation; Leukotriene B4; Male; Methylprednisolone; Neutrophils; Prostaglandins E; Rats; Rats, Inbred Strains; Regional Blood Flow; Wound Healing; Wounds and Injuries

Effects of dexamethasone on chemotactic activity to polymorphonuclear leukocytes (PMN) of a lipophilic fraction collected with the aid of octadecylsilyl silica cartridge from exudates of an allergic inflammation were investigated. The chemotactic activity of this fraction was attributable to leukotriene B4 fraction separated by means of a reversed phase high performance liquid chromatography. Local application of dexamethasone suppressed dose-dependently the chemotactic activity of the lipophilic fraction in parallel with the inhibition of PMN infiltration in the inflammatory sites.

Topics: Animals; Chemotaxis, Leukocyte; Chromatography, High Pressure Liquid; Dexamethasone; Inflammation; Leukotriene B4; Male; Neutrophils; Rats; Rats, Inbred Strains

Extreme sensitivity of airways to multiple stimuli characterizes asthma. Airway hyperresponsiveness can be produced experimentally in otherwise healthy subjects or animals by inflammatory damage (e.g., induced by respiratory viruses or by inhaled oxidants). Evidence is presented that cell-to-cell interactions play an important role in experimental hyperreactivity and that similar inflammatory cascades may play a similar role in clinical asthma. Although the importance of epithelial cells and neutrophils has been identified in the present studies, other inflammatory mechanisms (e.g., sensory nerve release of substance P, epithelial mast cells, eosinophils) may also play key roles. In exercise-induced bronchospasm, the stimulus (e.g., cooling or drying) must affect a cell (e.g., one near the epithelial surface) by decreasing temperature or by increasing osmolality. This signal may cause mediator release and a subsequent cascade, leading to contraction of smooth muscle. Environmental irritants (e.g., ozone) inhaled during exercise may potentiate these effects by producing further inflammation.

Topics: Animals; Arachidonic Acids; Asthma; Cell Communication; Chemotactic Factors; Dinoprostone; Dogs; Epithelial Cells; Epithelium; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Interleukin-8; Leukotriene B4; Neutrophils; Ozone; Prostaglandins E; Sputum

The effects of three anti-inflammatory drugs, which interfere with arachidonic acid transformation by three different enzymes, have been compared by using a simple model of tissue damage and foreign body rejection. In groups of control rats, subcutaneously implanted polyester sponges were rejected after a mean of 12 days. Indomethacin, which selectively inhibits prostaglandin synthesis, did not significantly change time to rejection but BW755C (3-amino-1-[m-(trifluoromethyl) phenyl]-2-pyrazoline), which is a dual inhibitor of prostaglandin and leukotriene synthesis, prolonged time to rejection to a mean of 22 days. The anti-inflammatory steroid dexamethasone, which reduces arachidonic acid metabolism by stimulating the formation of a phospholipase inhibitor, prolonged time to sponge rejection as BW755C did. Treatment with BW755C or dexamethasone was also accompanied by a reduction in total leukocyte numbers in inflammatory exudates collected at 1-14 days, whereas indomethacin increased leukocyte migration on days 1 and 2 and had no effect at later times. These results suggest that the inhibition of the leukotriene-forming lipoxygenase suppresses leukocyte activation and that this leads to a reduced rate of tissue damage in experimental inflammation.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Animals; Arachidonic Acid; Arachidonic Acids; Dexamethasone; Foreign-Body Reaction; Indomethacin; Inflammation; Leukocytes; Leukotriene B4; Male; Pyrazoles; Rats; SRS-A

BW755C (3-amino-1-[m-trifluoromethyl)phenyl]-2-pyrazoline HCl) reduced the concentration of leukotriene B4 (LTB4), thromboxane B2 (TXB2) and prostaglandin E2 (PGE2) in exudate derived from the subcutaneous implantation in rats of 0.5% carrageenan-impregnated polyester sponges. Polymorphonuclear leukocyte (PMN) migration into the inflammatory exudate was also decreased. The inhibition of LTB4 may, in part, account for the lower number of cells in the exudate since LTB4 is a potent leukotactic agent. Inhibition of LTB4-formation and cell migration by BW755C was dose-related, but the two dose-response curves were not parallel. Cell influx still occurred at doses of BW755C that completely inhibited formation of LTB4: this indicates that, although LTB4 may have a chemotactic role in-vivo, other factors must also contribute to cell migration into the inflammatory exudate. Treatment of rats with dexamethasone also caused a reduction in leukocytes and eicosanoids in the exudate. As with BW755C, there was a differential effect on PMN and LTB4: dexamethasone (1 mg kg-1) reduced PMN accumulation by 40% but LTB4 formation was inhibited by 70%. Leukocyte accumulation was also inhibited by the non-steroidal anti-inflammatory drugs (NSAID's), indomethacin and flurbiprofen. These drugs reduced the concentration of both PGE2 and TXB2 in exudate but that of LTB4 was unchanged. This suggests that reduction of PMN accumulation by indomethacin and flurbiprofen is mediated by a mechanism other than inhibition of LTB4-synthesis. Aspirin also reduced the levels of PGE2 and TXB2 in the exudate but did not consistently affect PMN influx, thereby confirming that inhibition of cyclo-oxygenase does not reduce cell migration in inflammation.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Animals; Anti-Inflammatory Agents; Aspirin; Cell Movement; Dexamethasone; Dinoprostone; Exudates and Transudates; Fatty Acids, Unsaturated; Indomethacin; Inflammation; Leukocyte Count; Leukocytes; Leukotriene B4; Male; Prostaglandins E; Pyrazoles; Rats; Thromboxane B2

Topics: Animals; Complement C5; Complement C5a; Eosinophils; Guinea Pigs; Histamine Release; Humans; Immunity, Cellular; Inflammation; Leukotriene B4; Muscle Contraction; Neutrophils; Platelet Activating Factor; Rats

Arachidonic acid plays a central role in a biological control system where such oxygenated derivatives as prostaglandins, thromboxanes, and leukotrienes are mediators. The leukotrienes are formed by transformation of arachidonic acid into an unstable epoxide intermediate, leukotriene A4, which can be converted enzymatically by hydration to leukotriene B4, and by addition of glutathione to leukotriene C4. This last compound is metabolized to leukotrienes D4 and E4 by successive elimination of a gamma-glutamyl residue and glycine. Slow-reacting substance of anaphylaxis consists of leukotrienes C4, D4, and E4. The cysteinyl-containing leukotrienes are potent bronchoconstrictors, increase vascular permeability in postcapillary venules, and stimulate mucus secretion. Leukotriene B4 causes adhesion and chemotactic movement of leukocytes and stimulates aggregation, enzyme release, and generation of superoxide in neutrophils. Leukotrienes C4, D4, and E4, which are released from the lung tissue of asthmatic subjects exposed to specific allergens, seem to play a pathophysiological role in immediate hypersensitivity reactions. These leukotrienes, as well as leukotriene B4, have pro-inflammatory effects.

Topics: Animals; Arachidonic Acids; Bronchi; Cats; Chemical Phenomena; Chemistry; Cricetinae; Guinea Pigs; Haplorhini; Humans; Hypersensitivity, Immediate; Inflammation; Leukocytes; Leukotriene B4; Mice; Microcirculation; Rabbits; Rats; SRS-A

Effects of glucocorticoids on human neutrophil responses to leukocyte migration inhibition factor (LIF) and neutrophil chemokinesis were examined using an agarose gel technique. The roles of endogenous monohydroxyeicosatetraenoic acids (HETE) and prostaglandins (PG) in basal neutrophil chemokinesis were also examined. Methylprednisolone sodium succinate (MPSS) in concentrations up to 200 micrograms/ml failed to inhibit the neutrophil response to LIF. MPSS enhanced neutrophil chemokinesis in a dose-related manner at concentrations from 2 micrograms/ml to 200 micrograms/ml (P less than 0.01). Since inhibition of membrane phospholipase activity by MPSS is known to decrease production of HETE and PG, the present data suggest that HETE and PG do not mediate basal neutrophil chemokinesis. This was confirmed by selectively inhibiting HETE production with the lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA) or PG production with the cyclooxygenase inhibitor indomethacin. Neutrophil chemokinesis was unaffected by 10(-5) M NDGA (P less than 0.05) or 10(-5) indomethacin (P less than 0.05).

Topics: Arachidonic Acid; Arachidonic Acids; Chemotaxis, Leukocyte; Humans; Inflammation; Leukocyte Migration-Inhibitory Factors; Leukotriene B4; Lymphokines; Methylprednisolone; Methylprednisolone Hemisuccinate; Neutrophils; Phytohemagglutinins

Topics: Animals; Arachidonic Acid; Arachidonic Acids; Humans; Hypersensitivity, Immediate; Inflammation; Leukotriene B4; Neutrophils; SRS-A

Leukotrienes (LT's) and prostaglandins (PG's) have been proposed as mediators of vascular permeability changes in inflammatory reactions. Also, prostaglandins, especially of the E-type, have been shown to enhance pain responses. In the present studies in rats, the effects of LTB4 and LTD4 on edema and pain thresholds were examined in combination with PGE1 and/or brewer's yeast. Subplantar injections of LTD4 or LTB4 induced small increases in paw thickness which were potentiated by the co-administration of PGE1. LTD4 alone had no significant effect on the development of the yeast paw edema. LTB4 was found to reduce significantly the yeast edema and this reduction could be reversed by administration PGE1. A small but significant decrease in pain threshold was caused by PGE1 and this was significantly enhanced in the presence of LTD4. LTB4, like PGE1, was found to cause slight hyperalgesia but no synergy between the two agents was observed. LTD4 was found to have no effect on the initial hypoalgesia or subsequent development of hyperalgesia caused by brewer's yeast. Both LTB4 and PGE1, however, prevented the initial hypoalgesia and significantly reduced the latency for development of yeast induced hyperalgesia. These effects of LTB4 are discussed in terms of possible release of cyclooxygenase products.

Topics: Alprostadil; Animals; Female; Hindlimb; Inflammation; Leukotriene B4; Pain; Prostaglandins E; Rats; Rats, Inbred Strains; SRS-A; Vocalization, Animal

Leukotriene B4 (LTB4) has been detected by radioimmunoassay in inflammatory exudates obtained following the implantation of saline- or carrageenan-soaked polyester sponges in rats. The immunoreactive material was confirmed as LTB4 after extraction and purification by high pressure liquid chromatography. The peak concentration (6.9 +/- 0.5 ng/ml) was detected 6 hr after implantation of sponges soaked in 0.5% carrageenan; thereafter the level declined and was undetectable after 16-24 hr. The concentration of LTB4 during the early phase of the inflammatory response (4-8 hr) is sufficient to induce leukocyte aggregation, chemotaxis and degranulation of polymorphonuclear leukocytes (PMN) in vitro. Therefore, LTB4 may mediate, at least in part, the influx of PMN and contribute to other events which characterise the inflammatory response. The level of thromboxane B2 (TXB2) in the inflammatory exudate followed a similar time-course to that of LTB4 although the maximum concentration was higher (15-30 ng/ml). However, prostaglandin E2 (PGE2) exhibited a different time-course; the maximum level (20-30 ng/ml) was also reached 6-8 hr after implantation but remained elevated at 24 hr. The PMN count in the sponges and the concentrations of both LTB4 and TXB2, but not PGE2, were significantly reduced by prior treatment of the animals with colchicine. This suggests that PMN are the major source of LTB4 and TXB2 in the inflammatory exudate whereas PGE2 is produced in significant amounts by other tissues.

Topics: Animals; Calcimycin; Chromatography, High Pressure Liquid; Colchicine; Dinoprostone; Inflammation; Leukocyte Count; Leukotriene B4; Male; Prostaglandins E; Rats; Rats, Inbred Strains; Thromboxane B2

Topics: Chemotaxis, Leukocyte; Granulocytes; Histamine; Humans; Hypersensitivity; Immunoglobulin E; Inflammation; Leukotriene B4; Lipoxygenase; Mast Cells; Neutrophils; Prostaglandins; SRS-A

Topics: Arachidonic Acids; Humans; Hypersensitivity; Inflammation; Leukotriene A4; Leukotriene B4; SRS-A

Topics: Animals; Humans; Inflammation; Leukotriene B4; Peptide Hydrolases; Platelet Activating Factor; SRS-A

The lipoxygenation of arachidonic acid in many different types of cells generates diverse mediators of hypersensitivity and inflammation. The leukotrienes represent one such family of mediators, which exert potent effects on smooth muscle, the microcirculation, and leukocytes. Leukocytes express distinct subsets of receptors for different leukotrienes. Transpeptidatic, peptidolytic, oxidative, and peroxidative pathways of leukocytes contribute substantially to the interconversion and biodegradation of leukotrienes. The 5-lipoxygenation of endogenous arachidonic acid appears to be a critical prerequisite for the activation of the function of leukocytes and some other cells. Natural and pharmacological inhibitors of 5-lipoxygenation in T lymphocytes noncytotoxically suppress the migration and transformation of the lymphocytes in response to antigens and mitogens. Lipoxygenase products of arachidonic acid thus fulfill important roles both as extracellular mediators and as functional intracellular constituents.

Topics: Arachidonic Acid; Arachidonic Acids; Chemotaxis, Leukocyte; Humans; Inflammation; Leukocytes; Leukotriene B4; Receptors, Cell Surface; SRS-A

Topics: Anti-Inflammatory Agents; Arachidonic Acids; Arthritis, Rheumatoid; Humans; Inflammation; Leukotriene B4; Prostaglandins

Recent findings have contributed substantially to a better understanding of the ontogeny and function of eosinophil leukocytes. Together with other granulocytes, the cells originate in the bone marrow from a common stem cell. Their development is regulated by genetic factors and by products of T-lymphocytes. Chemotactic factors of the complement cascade (C5a), lymphokines and eosinophil chemotactic leukotrienes (ECL) stimulate their migration to tissue sites. Generation and biological effectiveness of eosinophil chemotactic factors can be modulated in numerous ways, thus changing the outcome of the inflammatory event. The probably most important effector function of eosinophils is their cytotoxicity which plays a role in the killing of parasites. Markedly elevated numbers of eosinophils can, however, cause auto-aggression against the body's own cells, such as the Purkinje cells of the brain, cardiac muscle cells or epithelial cells of the skin and the bronchial tree. Eosinophils are therefore cells capable of both serving and damaging the human host.

Topics: Anaphylaxis; Autoimmune Diseases; Cell Differentiation; Chemotactic Factors, Eosinophil; Complement System Proteins; Eosinophils; Hematopoietic Stem Cells; Humans; Inflammation; Leukotriene B4; Mast Cells; Parasitic Diseases

Topics: Arachidonic Acids; Asthma; Humans; Hypersensitivity; Inflammation; Leukotriene A4; Leukotriene B4; Leukotriene E4; SRS-A

The leukocyte lipoxygenase products LTB4 and 5-HETE elicit human neutrophil and eosinophil chemotactic responses in vitro and in vivo (Fig. 4), and are present at elevated concentrations in the lesions of some human inflammatory diseases, such as rheumatoid arthritis and the spondyloarthritides. The chemotactic potency of LTB4 is similar to that of the minor fragment of the fifth component of human complement, termed C5a, and is 30- to 300-fold greater than that of 5-HETE and of other natural DHETE isomers. Human neutrophils possess distinct subsets of chemotactic factor receptors that are specific for LTB4 and for 5-HETE, as demonstrated by the selective competitive inhibition of the chemotactic responses to the parent stimuli by acetyl LTB4 and 5-HETE methyl ester, respectively, and by the failure of the lipid chemotactic factors to bind to isolated membrane protein constituents of the human neutrophil receptors for chemotactic formyl-methionyl peptides. LTB4 and 5-HETE also elicit human neutrophil and eosinophil chemokinesis, stimulate the uptake of calcium and D-glucose, and enhance the expression of C3b receptors on the leukocytes; however, they exert only a minimal effect on superoxide generation and lysosomal enzyme release. LTB4, but not 5-HETE, stimulates the release of calcium from previously unexchangeable intraneutrophil pools, as has been described for potent peptide chemotactic factors. Although far less potent than LTC4 and LTD4, LTB4 constricts peripheral airways, enhances mucous secretion in the airways of the lung, and dilates and enhances the permeability of the microvasculature in skin and other organs (Fig. 4). A variety of leukocyte functions, including chemotaxis, D-glucose uptake, and lysosomal enzyme release, are impaired in association with the depletion of endogenous lipoxygenase products. Exogenous 5-HETE reverses some of the functional deficits of HETE-depleted leukocytes. Inhibition of leukocyte lipoxygenase activity also suppresses the intracellular content of hydroperoxyeicosatetraenoic acids and of novel polar metabolites of arachidonic acid that may be critical to the activation of human neutrophils and eosinophils. Thus LTB4 and the less potent 5-HETE are active extracellular mediators of the leukocytic components of hypersensitivity and inflammation and may also serve an important role as intracellular mediators of leukocyte function.

Topics: Arachidonate Lipoxygenases; Arachidonic Acids; Chemotaxis; Eosinophils; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Leukocytes; Leukotriene B4; Lipoxygenase; Neutrophils; Oligopeptides; Receptors, Cell Surface; Receptors, Formyl Peptide

Topics: Animals; Arachidonic Acids; Humans; Inflammation; Leukotriene B4; Prostaglandins; Psoriasis; Skin; SRS-A

Topics: Anti-Inflammatory Agents; Bradykinin; Histamine; Humans; Inflammation; Leukotriene B4; Platelet Activating Factor; Prostaglandins; Serotonin

Topics: Animals; Arachidonic Acids; Chemical Phenomena; Chemistry; Humans; In Vitro Techniques; Inflammation; Isomerism; Leukocytes; Leukotriene B4; Lipoxygenase

Leukotrienes B4, C4, and D4, members of a recently discovered family of substances biosynthesized from arachidonic acid, were found to have potent microvascular actions in the hamster cheek pouch. When applied topically to the vascular network, leukotrienes C4 and D4 caused an intense constriction of arterioles, being similar to angiotensin in potency in this respect. The vasoconstriction induced by leukotrienes C4 and D4 was short-lived, and it was consistently followed by a marked and dose-dependent extravasation of macromolecules from postcapillary venules. Histamine did not constrict arterioles, but it elicited leakage of plasma, although on a molar basis it was no more than 1/1000th as potent as the leukotrienes. When used in the same concentration range as leukotrienes C4 and D4, leukotriene B4 did not evoke vasoconstriction or promote plasma leakage. On the other hand, leukotriene B4 caused a conspicuous and reversible adhesion of leukocytes to the endothelium in postcapillary venules. Our findings that leukotrienes induce microcirculatory alterations in vivo, closely resembling the early events in the acute inflammatory response, imply that leukotrienes, formed in several blood-borne and tissue-bound cells, may mediate important microcirculatory adjustments to noxious stimuli.

Topics: Animals; Arachidonic Acids; Capillary Permeability; Cell Adhesion; Cricetinae; Dose-Response Relationship, Drug; Endothelium; Inflammation; Leukocytes; Leukotriene B4; Male; SRS-A

Leukotriene B4 (LTB4 isomer III), which promotes the movement and aggregation of leucocytes in vitro also stimulates the chemo-attraction of leucocytes and their adherence to vascular endothelium in vivo. These effects were observed directly in the hamster cheek pouch preparation and on histological examination of sections from the rabbit mesentery. Intravenous injection of LTB4 (isomer III) into the rabbit resulted in a profound but transient neutropenia. Intradermal injection of LTB4 (isomer III) in the rabbit produced a rapid accumulation of neutrophils and this effect was also observed in skin chambers applied over abrasions on the rabbit back or the human forearm.

Topics: Animals; Arachidonic Acids; Cell Adhesion; Cheek; Cricetinae; Granulocytes; Inflammation; Leukocytes; Leukotriene B4; Mesocricetus; Rabbits; Skin

1. The inflammatory effects of hydroperoxy (HPETE) and hydroxy (HETE) acids, synthesized by arachidonic acid lipoxygenases, have been investigated in rabbit skin. 2. High doses (10-20 micrograms) of 5-, 12- or 15-HPETE or the 5,12-di-hydroxy acid, leukotriene B4 (0.1-1 micrograms), caused small but significant increases in plasma exudation following intra-dermal injection. 3. Leukotriene B4 was equipotent with prostaglandin E2 and prostacyclin in potentiating bradykinin-induced plasma exudation, and was 100 times more active in this property than any other lipoxygenase product tested. 4. Leukotriene B4-induced plasma exudation was enhanced by prostaglandin E2. 5. The mono-HETEs were relatively inactive in causing or enhancing plasma exudation. 6. Leukotriene B4 (0.1 microgram) or prostaglandin E1 (1.0 micrograms) significantly elevated leukocyte accumulation in rabbit skin, whereas PGE2, 5-HPETE, 5-HETE, 12-HPETE or 12-HETE were inactive at doses up to 1 microgram.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Animals; Arachidonic Acids; Bradykinin; Dose-Response Relationship, Drug; Epoprostenol; Exudates and Transudates; Inflammation; Leukocytes; Leukotriene B4; Leukotrienes; Lipid Peroxides; Prostaglandins E; Rabbits; Skin

Topics: Animals; Arachidonic Acids; Calcimycin; Chemotactic Factors; Chemotaxis, Leukocyte; Dose-Response Relationship, Drug; Guinea Pigs; Inflammation; Leukocyte Count; Leukotriene B4; Neutrophils; Rats

Arachidonic acid is metabolised either by cyclooxygenases to produce prostaglandins and thromboxanes or by lipoxygenases to produce mono-, di- and trihydroxyeicosatetraenoic acids (HETEs). Polymorphonuclear leukocytes (PMNs) release HETEs, including mono- and dihydroxy fatty acids, when exposed to stimuli such as the calcium ionophore A23187 (refs 1, 2). The mono-HETEs are assumed to be of particular importance with respect to effects on leukocyte function because they have been shown to possess both chemotactic and chemokinetic activities towards PMNs and eosinophils. However, we have now shown that the chemokinetic and aggregating activities released from rat and human PMNs exposed to ionophore A23187 (ref. 5) are not due to the release of mono-HETEs but to that of 5, 12-di-HETE (leukotriene B). This compound is active over the concentration range 10 pg ml-1 to 5 ng ml-1.

Topics: Animals; Arachidonic Acids; Calcimycin; Cell Aggregation; Chemotaxis, Leukocyte; Humans; Hydroxy Acids; Inflammation; Leukotriene B4; Lipoxygenase; Neutrophils; Rats

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Airway Obstruction; Animals; Arachidonic Acids; Capillary Permeability; Chemotactic Factors; Constriction, Pathologic; Eosinophils; Guinea Pigs; Humans; Hypersensitivity, Immediate; Inflammation; Leukotriene B4; Lipoxygenase; Muscle Contraction; Muscle, Smooth; Neutrophils; Rats; Skin; SRS-A; Trachea