leukotriene-b4 and Hyperplasia

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

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

Human genetics have implicated the 5-lipoxygenase enzyme in the pathogenesis of cardiovascular disease, and an inhibitor of the 5-lipoxygenase activating protein (FLAP) is in clinical development for asthma.. Here we determined whether FLAP deletion modifies the response to vascular injury.. Vascular remodeling was characterized 4 weeks after femoral arterial injury in FLAP knockout mice and wild-type controls. Both neointimal hyperplasia and the intima/media ratio of the injured artery were significantly reduced in the FLAP knockouts, whereas endothelial integrity was preserved. Lesional myeloid cells were depleted and vascular smooth muscle cell (VSMC) proliferation, as reflected by bromodeoxyuridine incorporation, was markedly attenuated by FLAP deletion. Inflammatory cytokine release from FLAP knockout macrophages was depressed, and their restricted ability to induce VSMC migration ex vivo was rescued with leukotriene B(4). FLAP deletion restrained injury and attenuated upregulation of the extracellular matrix protein, tenascin C, which affords a scaffold for VSMC migration. Correspondingly, the phenotypic modulation of VSMC to a more synthetic phenotype, reflected by morphological change, loss of α-smooth muscle cell actin, and upregulation of vascular cell adhesion molecule-1 was also suppressed in FLAP knockout mice. Transplantation of FLAP-replete myeloid cells rescued the proliferative response to vascular injury.. Expression of lesional FLAP in myeloid cells promotes leukotriene B(4)-dependent VSMC phenotypic modulation, intimal migration, and proliferation.

Topics: 5-Lipoxygenase-Activating Proteins; Animals; Bone Marrow Transplantation; Cell Movement; Cell Proliferation; Cells, Cultured; Cysteine; Disease Models, Animal; Endothelial Cells; Femoral Artery; Genotype; Hyperplasia; Inflammation Mediators; Leukotriene B4; Leukotrienes; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Myeloid Cells; Myocytes, Smooth Muscle; Neointima; Phenotype; Tenascin; Time Factors; Vascular Cell Adhesion Molecule-1; Vascular System Injuries

It is well known that eosinophilia is a key pathogenetic component of toxocariasis. The objective of the present study was to determine if there is an association between peritoneal and blood eosinophil influx, mast cell hyperplasia and leukotriene B(4) (LTB(4)) production after Toxocara canis infection. Oral inoculation of 56-day-old Wistar rats (N = 5-7 per group) with 1000 embryonated eggs containing third-stage (L3) T. canis larvae led to a robust accumulation of total leukocytes in blood beginning on day 3 and peaking on day 18, mainly characterized by eosinophils and accompanied by higher serum LTB(4) levels. At that time, we also noted increased eosinophil numbers in the peritoneal cavity. In addition, we observed increased peritoneal mast cell number in the peritoneal cavity, which correlated with the time course of eosinophilia during toxocariasis. We also demonstrated that mast cell hyperplasia in the intestines and lungs began soon after the T. canis larvae migrated to these compartments, reaching maximal levels on day 24, which correlated with the complete elimination of the parasite. Therefore, mast cells appear to be involved in peritoneal and blood eosinophil infiltration through an LTB(4)-dependent mechanism following T. canis infection in rats. Our data also demonstrate a tight association between larval migratory stages and intestinal and pulmonary mast cell hyperplasia in the toxocariasis model.

Topics: Animals; Eosinophilia; Hyperplasia; Intestines; Leukotriene B4; Lung; Male; Mast Cells; Peritoneal Cavity; Rats; Rats, Wistar; Toxocara canis; Toxocariasis

To evaluate the chemopreventive effects of boswellic acid and curcumin on 7,12-dimethyl benzanthracene(DMBA)-induced oral carcinogenesis in the hamster cheek pouch model.. Male Syrian golden hamsters (6 - 8 weeks old, 80 - 130 g in weight) were randomly divided into seven groups, with group A serving as the untreated negative control. The left cheek pouch of the remaining hamsters was topically treated with 0.5% DMBA in mineral oil three times a week for 6 weeks. They were then randomized to six groups with group B serving as a positive control and receiving no further treatment. Groups C-G were treated topically with 5, 10 mg/L boswellic acid, 5, 10 µmol/L curcumin, or the combination of 5 mg/L boswellic acid and 5 µmol/L curcumin three times per week for 18 weeks. The animals were injected with bromodeoxyuridine intraperitoneally at 50 mg/kg 2 h prior to killing. At the 25 th week all the hamsters were sacrificed and cheek pouch tissue was harvested. One half of the tissue was snap frozen in liquid nitrogen for analysis of arachidonic acid metabolites, and the other half was fixed in 10% phosphate-buffered saline(PBS)-buffered formalin for histopathological examination.. Six-weeks of DMBA followed by 18-weeks of topical application of boswellic acid and curcumin, both boswellic acid (5, 10 mg/L) and curcumin (5, 10 µmol/L) significantly inhibited the incidence from 93.8% to 73.9% (P > 0.05), numbers from 2.19 ± 0.98 to 1.13 ± 0.81 (P < 0.01) and size of visible tumors. Microscopically the incidence of squamous cell carcinoma and BrdU index were also significantly suppressed by boswellic acid and curcumin.. Both boswellic acid and curcumin were effective in preventing oral carcinogenesis in DMBA-induced hamster cheek pouch model.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Antineoplastic Agents; Bromodeoxyuridine; Carcinogenesis; Carcinogens; Carcinoma, Squamous Cell; Cheek; Cricetinae; Curcumin; Hyperplasia; Leukotriene B4; Male; Mesocricetus; Mouth Neoplasms; Precancerous Conditions; Random Allocation; Triterpenes

The lipid-derived inflammatory mediators leukotrienes (LTs) are produced during vascular injury. The aim of the present study was to determine the role of LT receptor signaling in the pathophysiology of in-stent stenosis.. New Zealand White rabbits were fed 0.3% cholesterol and subjected to angioplasty with balloon dilatation and stent implantation in the right carotid artery. Rabbits treated for 2 weeks with the BLT receptor antagonist BIIL284 (3 mg/kg once daily by oral gavage) displayed a significantly reduced in-stent intimal hyperplasia in carotid arteries compared with vehicle-treated rabbits. In addition, BIIL284 treatment significantly reduced the extracellular matrix metalloproteinase (MMP)-2 and MMP-9 activities in stented arteries. The inhibited MMP-9 activity was correlated with decreased macrophage content in the lesions. The LTB(4)-induced migration of vascular smooth muscle cells was significantly inhibited by transfection with siRNA against MMP-2. Finally, human arteries subjected to ex vivo angioplasty and stent implantation displayed an increased in-stent intimal hyperplasia and higher MMP-2 and -9 activities in the presence of LTB(4).. These results suggest a key role of LT signaling in the extracellular matrix degradation associated with hyperlipidemia and in-stent stenosis. In conclusion, targeting LT receptors may represent a therapeutic strategy in atherosclerosis and interventional cardiology.

Topics: Administration, Oral; Amidines; Angioplasty, Balloon; Animals; Carbamates; Carotid Artery, Common; Carotid Stenosis; Cell Line; Cell Movement; Cell Proliferation; Cholesterol, Dietary; Disease Models, Animal; Extracellular Matrix; Humans; Hyperplasia; Leukotriene Antagonists; Leukotriene B4; Macrophages; Male; Mammary Arteries; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Organ Culture Techniques; Rabbits; RNA Interference; RNA, Small Interfering; Secondary Prevention; Stents; Time Factors; Transfection

Leukotriene B(4) (LTB(4)), a potent leukocyte chemoattractant derived from the 5-lipoxygenase metabolism of arachidonic acid, exerts its action by means of specific cell surface receptors, denoted BLT(1) and BLT(2). In this study, BLT(1) receptor proteins were detected in human carotid artery atherosclerotic plaques, colocalizing with markers for macrophages, endothelial cells, and vascular smooth muscle cells (SMC). Challenge of human coronary artery SMC with either LTB(4) or U75302, a partial agonist that is selective for the BLT(1) receptor, induced an approximately 4-fold increase of whole-cell currents by using the patch-clamp technique, indicating that these cells express functional BLT(1) receptors. LTB(4) induced migration and proliferation of SMC in vitro, and treatment with the BLT receptor antagonist BIIL 284 (10 mg/kg, once daily) for 14 days after carotid artery balloon injury in vivo inhibited intimal hyperplasia in rats. In the latter model, SMC derived from the intima exhibited increased levels of BLT(1) receptor mRNA compared with medial SMC. BLT receptor up-regulation in the intima in vivo, as well as that induced by IL-1beta in vitro, were prevented by transfection with a dominant-negative form of Ikappa kinase beta carried by adenovirus, indicating that BLT(1) receptor expression depends on NF-kappaBeta. These results show that LTB(4) activates functional BLT(1) receptors on vascular SMC, inducing chemotaxis and proliferation, and that BLT(1) receptors were up-regulated through an Ikappa kinase beta/NF-kappaB-dependent pathway. Inhibition of LTB(4)/BLT(1) signaling during the response to vascular injury reduced intimal hyperplasia, suggesting this pathway as a possible target for therapy.

Topics: Amidines; Analysis of Variance; Animals; Atherosclerosis; Blotting, Western; Carbamates; Carotid Artery Injuries; Cell Movement; Electrophysiology; Fatty Alcohols; Glycols; Humans; Hyperplasia; Leukotriene B4; Male; Muscle, Smooth, Vascular; NF-kappa B; Patch-Clamp Techniques; Polymerase Chain Reaction; Purinergic P2 Receptor Agonists; Purinergic P2 Receptor Antagonists; Rats; Rats, Sprague-Dawley; Receptors, Leukotriene B4; Receptors, Purinergic P2; Signal Transduction; Tunica Intima; Up-Regulation

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

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