leukotriene-d4 and Bronchial-Hyperreactivity

Asthma is a chronic inflammatory and allergic disease that is mainly characterized by reversible airway obstruction and bronchial hyperresponsiveness. The incidence of asthma is increasing with more than 350 million people worldwide are affected. Up to now, there is no therapeutic option for asthma and most of the prescribed drugs aim to ameliorate the symptoms of the disease especially during the acute exacerbations after trigger exposure. Asthma is a heterogonous disease that involves interactions between inflammatory mediators and cellular components within the disease microenvironment including inflammatory and structural cells. Cysteinyl leukotrienes (cys-LTs) are inflammatory lipid mediators that have potent roles in asthma pathogenesis. CysLTs consisting of LTC

Topics: Acetates; Airway Remodeling; Animals; Anti-Asthmatic Agents; Asthma; Bronchial Hyperreactivity; Cyclopropanes; Cysteine; Gene Expression; Humans; Hypersensitivity; Indoles; Inflammation Mediators; Leukotriene Antagonists; Leukotriene D4; Leukotrienes; Phenylcarbamates; Quinolines; Receptors, Leukotriene; Sulfides; Sulfonamides; Tosyl Compounds

Leukotriene (LT) E(4) mediates many of the principal features of bronchial asthma, such as bronchial constriction, hyperresponsiveness, eosinophilia, and increased vascular permeability. Furthermore, it is the most stable of the cysteinyl leukotrienes (CysLTs) and can be active at the site of release for a prolonged time after its synthesis. There might be several reasons why LTE(4) has been forgotten. LTE(4) demonstrated low affinity for CysLT(1) and CysLT(2) receptors in equilibrium competition assays. It was less potent than other CysLTs in functional assays, such as calcium flux, in cells transfected with CysLT(1) and CysLT(2). The introduction of CysLT(1) antagonists into clinical practice diverted interest into CysLT(1)-related mechanisms, which were mediated mainly by LTD(4). However, experiments with animal models and human studies have revealed that LTE(4) has unique characteristics that cannot be explained by the current knowledge of CysLT(1) and CysLT(2). These activities include its potency relative to other CysLTs to increase airway responsiveness to histamine, to enhance eosinophilic recruitment, and to increase vascular permeability. Asthmatic airways also demonstrate marked in vivo relative hyperresponsiveness to LTE(4), especially in patients with aspirin-sensitive respiratory disease. This has stimulated a search for additional LT receptors that would respond preferentially to LTE(4) stimulation.

Topics: Animals; Aspirin; Asthma; Bronchial Hyperreactivity; Drug Hypersensitivity; Histamine; Humans; Leukotriene C4; Leukotriene D4; Leukotriene E4; Methacholine Chloride; Receptors, Leukotriene; Skin

Aspirin is not only one of the best-documented medicines in the world, but also one of the most frequently used drugs of all times. In addition to its role as an analgesic, aspirin is being increasingly used in the prophylaxis of ischemic heart disease and strokes. The prevalence of aspirin intolerance is around 5 to 6%. Up to 20% of the asthmatic population is sensitive to aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) and present with a triad of rhinitis, sinusitis, and asthma when exposed to the offending drugs. This syndrome is referred to as aspirin-induced asthma (AIA). The pathogenesis of AIA has implicated both the lipoxygenase (LO) and the cyclooxygenase (COX) pathways. By inhibiting the COX pathway, aspirin diverts arachidonic acid metabolites to the LO pathway. This also leads to a decrease in the levels of prostaglandin (PG) E(2), the anti-inflammatory PG, along with an increase in the synthesis of cysteinyl leukotrienes (LTs). Evidence suggests that patients with AIA have increased activity of LTC(4) synthase, the rate-limiting enzyme in the cysteinyl LT synthesis, in their bronchial biopsy specimens, thereby tilting the balance in favor of inflammation. LT-modifying drugs are effective in blocking the bronchoconstriction provoked by aspirin and are used in the treatment of this condition. Aspirin desensitization has a role in the management of AIA, especially in patients who need prophylaxis from thromboembolic diseases, myocardial infarction, and stroke. This review covers the latest understanding of pathogenesis, clinical features, and management of AIA.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acids; Aspirin; Asthma; Bronchial Hyperreactivity; Cyclooxygenase Inhibitors; Desensitization, Immunologic; Dinoprostone; Drug Hypersensitivity; Glutathione Transferase; Humans; Leukotriene Antagonists; Leukotriene D4; Lipoxygenase; Rhinitis; Sinusitis

Heparin besides its anticoagulant properties, possesses anti-inflammatory actions. Inhaled heparin has been shown to reduce early and late phase of asthmatic reaction and suppresses allergen induced rise in bronchial hyperreactivity. The exact mechanism of heparin action in bronchial asthma remains obscure. The mechanism involved in the control of bronchial hyperreactivity by heparin has been studied little and is yet poorly understood. The purpose of the present study was to investigate the effect of inhaled heparin on the airway response to leukotriene D4 Fourteen children with typical history of mild atopic asthma participated in this randomized, double-blind, placebo controlled and cross-over study. At the first visit subjects underwent provocation challenge test with leukotriene D4. Patients came back 14 days later to inhale heparin or placebo followed by provocation test with leukotriene. The third study day was 14 days after the second day and provocation test was performed in the same manner except for that patients who inhaled heparin at the second visit, now were administered placebo and opposite. Ten patients completed the study. One patient was withdrawn from the study because of consent withdrawal and three patients were unable to complete the provocation test because of asthma exacerbation. Single dose of inhaled heparin significantly decreased bronchial hyperreactivity to leukotriene in children with mild asthma (p = 0.005). PC20L after heparin inhalation increased in eight patient and decreased in two. It has been shown that histamine, metacholine, and leukotriene play a role in eosinophil recruitment to the airway. Since histamine, metacholine and leukotriene act through receptor binding to protein G, it is possible that heparin (by displacing eosinophil proteins from receptor-protein G binding) restore binding between receptor and G protein and in such mechanism, decrease bronchial hyperreactivity to leukotriene. In our study heparin was inhaled just before leukotriene provocation test and thus the effect of heparin on eosinophil proteins is less likely possible.

Topics: Administration, Inhalation; Adolescent; Asthma; Bronchial Hyperreactivity; Bronchial Provocation Tests; Child; Cross-Over Studies; Double-Blind Method; Heparin; Humans; Leukotriene D4

From bronchoprovocation studies and investigations of the acute effects of drugs that inhibit leukotrienes (LT), the hypothesis has emerged that leukotrienes are important mediators of airway obstruction and other symptoms in aspirin-intolerant asthma (AIA). However, it has yet not been shown if subjects with AIA respond favorably to clinical treatment with leukotriene inhibitors. Therefore, in a double-blind placebo-controlled crossover study, we examined the effects of 6 wk of treatment with the leukotriene-pathway inhibitor zileuton (600 mg, four times daily) in 40 patients with well-characterized AIA. The treatment was added to existing therapy, which included medium to high doses of inhaled (average daily dose 1,030 microg of beclomethasone or budesonide) or oral glucocorticosteroids (4 to 25 mg/d) for all but one of the patients. On top of this treated baseline, there were no significant effects of adding placebo, indicating that their asthma was kept relatively stable. However, there was an acute and chronic improvement in pulmonary function after treatment with zileuton, expressed both as increased FEV1 from baseline compared with placebo, and higher morning and evening peak expiratory flow rate (PEFR) values on zileuton treatment compared with placebo. The improvements occurred despite lower use of rescue bronchodilator with zileuton. Zileuton also diminished nasal dysfunction, which is one of the cardinal signs of AIA. There was a remarkable return of smell, less rhinorrhea, and a trend for less stuffiness and higher nasal inspiratory flow during treatment with zileuton. Zileuton caused a small but distinct reduction of bronchial hyperresponsiveness to histamine and inhibited aspirin-induced bronchoconstriction. Zileuton inhibited urinary excretion of LTE4 but did not change airway reactivity to inhaled LTD4, supporting that zileuton specifically inhibited leukotriene biosynthesis. The findings indicate that leukotrienes are important mediators of persistent airway obstruction and chronic nasal dysfunction in AIA. The study also suggests that addition of a leukotriene pathway inhibitor such as zileuton may bring about greater control of asthma than what is achieved by treatment with medium to high doses of glucocorticosteroids alone.

Topics: Adrenergic beta-Agonists; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Asthma; Bronchial Hyperreactivity; Bronchial Provocation Tests; Cross-Over Studies; Double-Blind Method; Drug Therapy, Combination; Female; Forced Expiratory Volume; Glucocorticoids; Histamine; Humans; Hydroxyurea; Leukotriene Antagonists; Leukotriene D4; Lipoxygenase Inhibitors; Male; Middle Aged; Peak Expiratory Flow Rate

Cysteinyl leukotrienes are potent inflammatory mediators that are considered to play a role in the pathophysiology of asthma. It can be postulated that leukotrienes exert their bronchoconstricting effects, in part, through secondary release of endogenous neuropeptides. We examined the effect of inhaled thiorphan, an inhibitor of a neuropeptide degrading enzyme, on the concentration-response curve to leukotriene D4 (LTD4) in a two-period, double-blind, cross-over and placebo-controlled study, in 16 nonasthmatic and 12 asthmatic subjects. Thiorphan or placebo were aerosolized and administered in two 0.5 ml doses of 1.25 mg.ml-1 each, 10 min prior to LTD4 inhalation. The airway response was measured by forced expiratory volume in one second (FEV1) and partial expiratory flow-volume curves (expiratory flow at 40% of forced vital capacity; V40p), and expressed as % fall from baseline. Complete concentration-response curves to inhaled LTD4 were recorded and characterized by their position (provocative concentration producing a 20% fall in FEV1 and a 40% fall in V40p; PC20FEV1 and PC40 V40p) and, in the nonasthmatics, also by the maximal-response plateau (MFEV1, MV40p). Post-pretreatment baseline values of FEV1 and V40p were not different between thiorphan and placebo pretreatment. In both groups of subjects, there was no significant difference in lnPC40V40p or lnPC20FEV1 to LTD4 between the two pretreatments mean difference +/- SD (in doubling concentrations): 0.12 +/- 0.73 and -0.19 +/- 1.23, respectively, in asthmatics; and 0.17 +/- 0.95 and -0.99 +/- 1.95, respectively, in nonasthmatics. The maximal-response plateau could not be obtained in the majority of the asthmatic subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Administration, Inhalation; Adult; Asthma; Bronchial Hyperreactivity; Bronchial Provocation Tests; Double-Blind Method; Forced Expiratory Volume; Humans; Leukotriene D4; Male; Neprilysin; Thiorphan

Oral cysteinyl-leukotriene (LT) receptor antagonists such as montelukast are used for reducing airway inflammation and exacerbations. However, inhaled therapy using LT receptor antagonists has not been studied. In the present study, the effect of inhaled montelukast was investigated on airway hyperresponsiveness measured by cysteinyl-LT induced bronchoconstriction in an animal model of asthma. Bronchoconstriction responses were induced by inhaled LTC4 and LTD4 (0.2 microg/ml each) or three doses of intravenous LTC4 and LTD4 (0.3, 1, 3 microg/kg) in ovalbumin (OVA)-sensitized Hartley male guinea-pigs. The response was measured by the change in peak pressure of airway opening (Pao). The effect of montelukast was evaluated by the comparison of bronchoconstriction responses between the groups of animals pre-treated with 15-min inhalation of 10mg/ml montelukast and saline. To evaluate the tissue injury which might be caused by montelukast inhalation, lung tissues were examined for the histology. The broncoconstriction responses induced by inhaled LTC4 and LTD4 were enhanced by OVA sensitization in the guinea-pigs. In sensitized animals, the significant increases in peak Pao were 18.5+/-2.1 cmH(2)O by LTC4 inhalation and 25.0+/-1.6 cmH(2)O by LTD4 inhalation on average. Prior treatment of inhaled montelukast potently suppressed the peak Pao increases induced by both inhaled and intravenous LTC4 and LTD4 (all P<0.01 vs. saline control). Moreover, the suppression of inhaled montelukast against LTD4-induced bronchoconstriction was observed for at least up to 24h. According to the histological examination, montelukast inhalation produced no injury to the lung tissue. Inhaled montelukast, a cysteinyl-LT receptor antagonist, was effective in inhibiting cysteinyl-LT-induced acute bronchoconstriction, and may have the potential for clinical use as a new asthma drug.

Topics: Acetates; Administration, Inhalation; Animals; Asthma; Bronchial Hyperreactivity; Bronchoconstriction; Cyclopropanes; Cysteine; Disease Models, Animal; Guinea Pigs; Immunologic Factors; Leukotriene Antagonists; Leukotriene C4; Leukotriene D4; Leukotrienes; Lung; Male; Ovalbumin; Quinolines; Sulfides

Viral infection causes asthma exacerbations and airway hyperreactivity. Toll-like receptor 3 (TLR3) recognizes double-stranded RNA (dsRNA) of viral or synthetic origin in a fashion different from protein kinase R (PKR). The aim of this study was to examine the expression and function of TLR3 in human airway smooth muscle (ASM) cells.. Expression of TLR3 and muscarinic receptor (MR), histamine receptor (HR), and cysteinyl leukotriene receptor (CysLTR) subtypes was analyzed by quantitative real-time PCR, flow cytometry, or Western blotting. It was assessed whether ASM cells respond to polyinosinic-polycytidylic acid (poly I:C), a synthetic analog of dsRNA, with alterations in M2R, M3R, H1R, and CysLT1R expression. The function of these subtypes was evaluated by cholinergic regulation of forskolin-stimulated cyclic AMP accumulation or by mobilization of intracellular calcium upon stimulation.. ASM cells expressed TLR3 and PKR, and intracellular TLR3 expression was demonstrated. Poly I:C caused decreased M2R and increased M3R expression, without affecting H1R and CysLT1R expression. Poly I:C-treated cells showed decreased cholinergic inhibition of forskolin-stimulated cyclic AMP accumulation and enhanced calcium flux in response to acetylcholine, but not to histamine and LTD4. These modulating effects of poly I:C were reversed by chloroquine, but not by 2-aminopurine.. The data indicate that poly I:C internalized by ASM cells differentially regulates M2R and M3R expression and function by interacting with TLR3 rather than with PKR, suggesting that these changes may contribute to airway hyperreactivity.

Topics: 2-Aminopurine; Bronchial Hyperreactivity; Calcium Signaling; Cells, Cultured; Chloroquine; Colforsin; Cyclic AMP; eIF-2 Kinase; Gene Expression Regulation; Histamine; Humans; Leukotriene D4; Membrane Proteins; Muscarinic Antagonists; Myocytes, Smooth Muscle; Poly I-C; Receptor, Muscarinic M2; Receptor, Muscarinic M3; Receptors, Histamine H1; Receptors, Leukotriene; Signal Transduction; Toll-Like Receptor 3

Cysteinyl leukotrienes (CysLTs) exert potent proinflammatory actions and contribute to many of the symptoms of asthma. Using a model of allergic sensitization and airway challenge with Aspergillus fumigatus (Af), we have found that Th2-type inflammation and airway hyperresponsiveness (AHR) to methacholine (MCh) were associated with increased LTD(4) responsiveness in mice. To explore the importance of increased CysLT signaling in airway smooth muscle function, we generated transgenic mice that overexpress the human CysLT1 receptor (hCysLT(1)R) via the alpha-actin promoter. These receptors were expressed abundantly and induced intracellular calcium mobilization in airway smooth muscle cells from transgenic mice. Force generation in tracheal ring preparations ex vivo and airway reactivity in vivo in response to LTD(4) were greatly amplified in hCysLT(1)R-overexpressing mice, indicating that the enhanced signaling induces coordinated functional changes of the intact airway smooth muscle. The increase of AHR imposed by overexpression of the hCysLT(1)R was greater in transgenic BALB/c mice than in transgenic B6 x SJL mice. In addition, sensitization- and challenge-induced increases in airway responsiveness were significantly greater in transgenic mice than that of nontransgenic mice compared with their respective nonsensitized controls. The amplified AHR in sensitized transgenic mice was not due to an enhanced airway inflammation and was not associated with similar enhancement in MCh responsiveness. These results indicate that a selective hCysLT(1)R-induced contractile mechanism synergizes with allergic AHR. We speculate that hCysLT(1)R signaling contributes to a hypercontractile state of the airway smooth muscle.

Topics: Actins; Animals; Aspergillus fumigatus; Base Sequence; Bronchial Hyperreactivity; DNA Primers; DNA Probes; Exons; Humans; Immunization; In Situ Hybridization, Fluorescence; Leukotriene D4; Lung; Membrane Proteins; Methacholine Chloride; Mice; Mice, Transgenic; Muscle, Smooth; Promoter Regions, Genetic; Receptors, Leukotriene; Reverse Transcriptase Polymerase Chain Reaction

Evidence suggests that small airways contribute to clinically significant processes in asthma. Cysteinyl leukotrienes (CysLTs) are considered to be pivotal mediators in the pathogenesis of asthma. Montelukast (MK), a specific CysLT1 receptor antagonist, is metabolized in two main hydroxylated metabolites (termed M5 and M6, respectively).. The aims of this study were to compare the responsiveness of small and large human bronchi to the three CysLTs, to evaluate the antagonist activity of MK, M5 and M6 in these preparations of human bronchi, and to characterize the CysLT receptors involved in the contractile response.. In isolated small bronchus (i.d. 0.5-2 mm), the potencies (-log molar EC50) of LTC4, LTD4 and LTE4 were 9.3 (n=11), 9.1 (n=30) and 8.4 (n=14), respectively. The three CysLTs were about 30-fold more potent in small bronchi than in larger bronchi (i.d. 4-6 mm). In small bronchi, MK significantly shifted to the right the CysLT concentration-effect curves with pA2 values against LTC4, LTD4 and LTE4 of 9.1 (n=3), 9.0 (n=11) and 8.7 (n=5), respectively. The antagonist potencies of M6 and M5 were similar to MK and fivefold lower, respectively. A similar activity of MK against the three CysLTs suggested that CysLT1 receptors are involved in the contraction of human bronchus. Analysis by RT-PCR also indicated that human bronchus mainly expressed CysLT1 receptors.. MK exerts a potent antagonist activity against the particularly potent constricting effects of CysLTs in isolated human small bronchi, which only expressed the CysLT1 receptor subtype. The metabolites of MK are also potent in vitro antagonists, but may not participate in the therapeutic activity of MK due to their low plasma concentrations in patients treated with the recommended dose of MK.

Topics: Acetates; Adult; Aged; Aged, 80 and over; Bronchi; Bronchial Hyperreactivity; Bronchial Provocation Tests; Cyclopropanes; Dose-Response Relationship, Drug; Female; Humans; In Vitro Techniques; Leukotriene Antagonists; Leukotriene C4; Leukotriene D4; Leukotriene E4; Male; Middle Aged; Quinolines; Reverse Transcriptase Polymerase Chain Reaction; Sulfides

It has been demonstrated that both cysteinyl leukotrienes (cysLTs) and cytokines are involved in the pathophysiology of bronchial asthma. Nonetheless, the exact mechanism involved in the interaction between these 2 molecules has yet to be determined.. The aim of the present study was to determine the effects of cysLTs on allergic airway inflammation and allergen-specific cytokine production in a murine model of asthma.. Four groups of BALB/c mice (control mice, Dermatophagoides farinae allergen-sensitized mice, pranlukast cysLT receptor antagonist-treated allergen-sensitized mice, and dexamethasone-treated allergen-sensitized mice) were examined.. Allergen-sensitized mice exhibited increased airway responsiveness and inflammation. Pranlukast-treated mice showed significant attenuation of these changes concomitant with reduction of T(H)2 cytokine and IFN-gamma production by isolated lung mononuclear cells (MNCs). A much stronger inhibition of all cytokines was noted in dexamethasone-treated mice. Pranlukast also significantly inhibited production of RANTES and activation of nuclear factor kappa B (NF-kappa B) in the isolated lung MNCs. Leukotriene D(4) stimulated isolated lung MNCs to produce RANTES but not any other cytokines and also activated NF-kappa B in these cells.. Our results suggest that cysLTs activate NF-kappa B and induce RANTES production from isolated lung MNCs, which in turn might cause migration of eosinophils and activated T lymphocytes into the airway.

Topics: Animals; Antigens, Dermatophagoides; Asthma; Bronchial Hyperreactivity; Bronchitis; Chemokine CCL5; Chromones; Cysteine; Cytokines; Female; Inflammation Mediators; Leukotriene Antagonists; Leukotriene D4; Leukotrienes; Lung; Mice; Mice, Inbred BALB C; Monocytes; NF-kappa B; Transcription Factor RelA

Inhalation of heparin attenuates hyperventilation-induced bronchoconstriction in humans and dogs. The purpose of this study was to determine whether heparin inhibits the late-phase response to hyperventilation, which is characterized by increased peripheral airway resistance (RP), eicosanoid mediator production, neutrophilic/ eosinophilic inflammation, and airway hyperreactivity (AHR) at 5 h after dry air challenge (DAC). Fiberoptic bronchoscopy was used to record RP and airway reactivity (DeltaRP) to aerosol and intravenous histamine before and 5 h after DAC. Bronchoalveolar lavage fluid (BALF) cells and eicosanoid mediators were also measured approximately 5 h after DAC. DAC of vehicle-treated bronchi resulted in late-phase airway obstruction (approximately 120% increase over baseline RP), inflammation, increased BALF concentrations of leukotriene (LT) C(4), LTD(4), and LTE(4) and prostaglandin (PG)D(2), and AHR. Pretreatment with aerosolized heparin attenuated late-phase airway obstruction by approximately 50%, inhibited eosinophil infiltration, reduced BALF concentrations of LTC(4), LTD(4), and LTE(4) and PGD(2), and abolished AHR. We conclude that heparin inhibits hyperventilation-induced late-phase changes in peripheral airway function, and does so in part via the inhibition of eosinophil migration and eicosanoid mediator production and release.

Topics: Administration, Inhalation; Airway Resistance; Animals; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Bronchoscopy; Disease Models, Animal; Dogs; Drug Evaluation, Preclinical; Eicosanoids; Eosinophils; Heparin; Humans; Hyperventilation; Inflammation; Leukotriene C4; Leukotriene D4; Leukotriene E4; Male; Neutrophils; Prostaglandin D2; Time Factors

Airway obstruction, hyperresponsiveness, and the accumulation and persistence within the airways of inflammatory cells characterize asthma. Interleukin (IL)-3, granulocyte macrophage colony- stimulating factor (GM-CSF), and IL-5 are among several cytokines that have been shown to be increased in asthma and to contribute to atopic inflammation. They mediate their effect via receptors that have a common beta subunit (beta(c)). We hypothesized that blocking of this common beta(c) would impair the airway response to antigen. We report that an antisense (AS) phosphorothioate oligodeoxynucleotide (ODN) found to specifically inhibit transcription of the beta(c) in rat bone marrow cells also caused inhibition of beta(c) mRNA expression and of immunoreactive cells within the lungs of Brown Norway (BN) rats when injected intratracheally (p < 0.01). Inhibition of beta(c) significantly reduced (p < 0.01) experimentally induced eosinophilia in vivo in ovalbumin (OVA)-sensitized BN rats after antigen challenge. Furthermore, when compared with mismatch-treated rats, beta(c) AS-ODN caused inhibition of antigen-induced airway hyperresponsiveness to leukotriene D4. Taken together, our findings demonstrate that the common beta(c) of IL-3, IL-5, and GM-CSF receptors is involved in the eosinophil influx and airway hyperresponsiveness that follow OVA challenge and underscore the potential utility of a topical antisense approach targeting beta(c) for the treatment of asthma.

Topics: Animals; Antigens; Asthma; Bone Marrow Cells; Bronchial Hyperreactivity; Cell Count; Cells, Cultured; Dose-Response Relationship, Drug; Eosinophils; Immunization; Leukotriene D4; Lung; Male; Oligonucleotides, Antisense; Ovalbumin; Rats; Rats, Inbred BN; Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; Receptors, Interleukin; Receptors, Interleukin-3; Receptors, Interleukin-5; RNA, Messenger; Transcription, Genetic

To compare responses of bronchial rings obtained from healthy horses and horses affected with summer pasture-associated obstructive pulmonary disease (SPAOPD) to selected mediators of airway hyperreactivity in vitro.. Bronchial rings from 6 healthy horses and 6 horses affected with SPAOPD.. Bronchial rings obtained from each group of horses were mounted in organ baths and attached to force transducers interfaced with a polygraph. After applying 2g of tension, each ring was allowed to equilibrate for 45 minutes in Tyrode's solution at 37 C. Cumulative concentration-response relationships to graded concentrations of selected mediators (10(-8) to 10(-4) M) were determined and analyzed for significance at each concentration.. Acetylcholine, histamine, 5-hydroxytryptamine, and leukotriene D4 induced concentration-dependent contractile responses in bronchial rings. Prostaglandin F2alpha induced weak and inconsistent contractile responses. The other 2 agents, norepinephrine and substance P, did not induce concentration-dependent responses. Considering the overall group-drug effect, acetylcholine, histamine, 5-hydroxytryptamine, and leukotriene D4 were effective in inducing consistent concentration-dependent contractile responses in both groups. Only 5-hydroxytryptamine and histamine induced significant responses in contractility between groups. The response of bronchial rings from horses with SPAOPD to 5-hydroxytryptamine was significantly greater than those from control horses, whereas the response to histamine was significantly lower. Significant responses were evident at concentrations ranging from 10(-6) to 10(-4) M for both drugs.. Because the airways of horses with SPAOPD had increased responsiveness to 5-hydroxytryptamine in vitro, treatment modalities using 5-hydroxytryptamine antagonists should be investigated to address this phenomenon.

Topics: Acetylcholine; Animals; Bronchi; Bronchial Hyperreactivity; Dose-Response Relationship, Drug; Drug Synergism; Histamine; Horse Diseases; Horses; In Vitro Techniques; Inflammation Mediators; Leukotriene D4; Lung Diseases, Obstructive; Muscle Contraction; Seasons; Serotonin

Airway hyperresponsiveness (AHR) is one of the characteristic features of human asthma. The presence of AHR and the precise mechanisms immediately after establishment of sensitization in guinea pigs are unclear, although there are many reports showing allergen exposure that causes an increase in bronchial responsiveness associated with eosinophil influx into the airway in sensitized guinea pigs.. We investigated the inhibitory effects on AHR to histamine of ONO-1078, a leukotriene antagonist; indomethacin, a cyclooxygenase inhibitor; S-145, a thromboxane A(2) (TXA(2)) antagonist, and Y-24180, a platelet-activating factor (PAF) antagonist, to assess the involvement of chemical mediators in AHR employing ovalbumin (OA) sensitized guinea pig models.. Male Hartley guinea pigs were used. Each group comprised 4-7 animals. The animals were sensitized to OA, injecting intraperitoneally 30 mg of cyclophosphamide and 2,000 microg of OA together with 100 mg of aluminum hydroxide as the adjuvant. The guinea pigs were artificially ventilated via a cannula using a small-animal respirator after intraperitoneal anesthesia with pentobarbital sodium for tracheotomy. The pressure at the airway opening (PAO) was measured using a differential pressure transducer, and a differential pressure of peak PAO (peak DeltaPAO) at inspiratory phase as an overall index of bronchial response to bronchoactive agents was used. While being artificially ventilated, the animals were exposed to physiological saline solution containing various concentrations of histamine (4.9, 9.8, 20, 39, 78, and 156 microg/ml) by inhalation for 30 s at 3-min intervals. Determinations were made at 1 min after each inhalation. The chemical mediators were each (30 mg/kg of ONO-1078, 3 mg/kg of S-1452, and 1 mg/kg of Y-24180) administered orally to sensitized guinea pigs, and the airway response to histamine was assessed. Each group comprised 4-7 animals.. The airway response to histamine was significantly greater in the sensitized group than in the nonsensitized group at histamine concentrations of 36 (p < 0.05), 78, and 156 mg/ml (p < 0.01). Leukotrienes C(4) and D(4): 30 mg/kg of ONO-178 did not show any inhibitory effect on airway response to inhaled histamine. Cyclooxygenase: 5 mg/kg of indomethacin did not show any inhibitory effect on the airway response to inhaled histamine. TXA(2): the AHR to inhaled histamine at doses of 9.8, 39, 78, and 156 microg/ml was significantly inhibited by prior administration of 3 mg/kg of S-1452. PAF: the AHR to inhaled histamine at doses of 9.8, 39, and 78 microg/ml was significantly inhibited by prior administration of 1 mg/kg of Y-24180.. S-1452 (3 mg/kg) and Y-24180 (1 mg/kg) significantly inhibited AHR to histamine, while ONO-108 (30 mg/kg) and indomethacin (5 mg/kg) did not. The results suggest that TXA(2) and PAF are involved in AHR in OA-sensitized guinea pigs.

Topics: Airway Resistance; Animals; Asthma; Bronchial Hyperreactivity; Disease Models, Animal; Dose-Response Relationship, Drug; Guinea Pigs; Histamine; Indomethacin; Leukotriene C4; Leukotriene D4; Male; Ovalbumin; Platelet Activating Factor; Probability; Reference Values; Sensitivity and Specificity; Thromboxane A2

YM976 is a novel and specific phosphodiesterase 4 inhibitor. In our previous report, we indicated that YM976 has less emetogenicity, a major adverse effect of PDE4 inhibitors, than rolipram. In the present study, we examined the antiasthmatic effects of YM976 in guinea pigs. YM976 orally administered exhibited inhibition of antigen-induced bronchoconstriction, airway plasma leakage, airway eosinophil infiltration, and airway hyperreactivity (AHR), with ED(50) values of 7.3, 5.7, 1.0, and 0.52 mg/kg, respectively. Rolipram also dose dependently suppressed these responses. Prednisolone suppressed eosinophil infiltration and AHR, whereas it failed to inhibit bronchoconstriction and plasma leakage. Theophylline moderately suppressed bronchoconstriction and edema, but neither eosinophil infiltration nor AHR. YM976 suppressed the peroxidase activity in the bronchoalveolar lavage fluid, and elevated the intracellular peroxidase activity and cAMP contents of infiltrated cells, suggesting that YM976 inhibited not only the infiltration but also the activation of leukocytes. In vitro studies revealed that YM976 potently suppressed eosinophil activation (EC(30) = 83 nM), and exerted a little relaxation on LTD(4)-precontracted tracheal smooth muscle (EC(50) = 370 nM). Rolipram exhibited a potent tracheal relaxation activity (EC(50) = 50 nM). In vivo studies indicated that the inhibitory effect of YM976 on LTD(4)-induced bronchospasm was marginal even at 30 mg/kg p.o., although rolipram significantly inhibited the bronchospasm at the same dose. These results suggested that YM976, unlike rolipram, showed the inhibition of antigen-induced airway responses due to anti-inflammatory effects, but not to direct tracheal relaxation. In conclusion, YM976 may have potential therapeutic value in the treatment of asthma through its anti-inflammatory activities.

Topics: Animals; Anti-Asthmatic Agents; Bronchial Hyperreactivity; Bronchial Spasm; Bronchoconstriction; Eosinophils; Guinea Pigs; In Vitro Techniques; Leukotriene D4; Lung; Male; Phosphodiesterase Inhibitors; Pyridines; Pyrimidinones; Superoxides

To evaluate clinical significance of measurement of urinary leukotriene E4 (LTE4) in asthmatic patients without attack, we measured urinary LTE4 in 68 asthmatic patients without attack and investigated its correlation with severity of asthma, % FEV1, bronchial hyperresponsiveness and peripheral eosinophil counts. Values of urinary LTE4 were significantly higher in the asthmatic patients (113.6 +/- 9.7 pg/mg.cr) than in healthy control subjects (67.8 +/- 4.7, n = 31), and the level of urinary LTE4 was in proportion to the severity of disease. Urinary LTE4 showed significant negative correlation with % FEV1 in atopic patients (Rs = -0.43, p = 0.025, n = 28), which was not recognized in non-atopic patients. Urinary LTE4 showed no significant correlation with bronchial hyperresponsiveness and peripheral eosinophil counts. Our findings suggested that basal LTE4 in urine reflected chronic airway inflammation of asthma.

Topics: Adult; Asthma; Bronchial Hyperreactivity; Female; Humans; Leukotriene D4; Male; Middle Aged; Severity of Illness Index

The role of 5-lipoxygenase (5-LO) products in the asthmatic bronchoconstriction is evident. However, the role of 5-LO products in airway hyperresponsiveness (AHR) and airway inflammation is still under discussion. The aim of the present study is to investigate the role of leukotriene D(4) (LTD(4)) in AHR and allergic airway eosinophilia in mice.. The effect of LTD(4) inhalation on antigen-induced AHR and airway eosinophilia was investigated in 5-LO gene-deficient mice.. After three inhalations of LTD(4), airway responsiveness to acetylcholine was not altered in normal or allergic wild-type and 5-LO knockout (KO) mice. In contrast, the number of eosinophils in 5-LO KO allergic mice increased to the level of wild-type allergic mice after the inhalation of LTD(4). These observations were confirmed by a histopathological study of the lungs. No change in the cytokine levels in bronchoalveolar lavage fluid and serum immunoglobulin levels was shown after LTD(4) inhalation.. These findings suggest that LTD(4) plays a role in eosinophilic airway inflammation but not in AHR in mice.

Topics: Administration, Inhalation; Animals; Antigens; Arachidonate 5-Lipoxygenase; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Immunoglobulin E; Immunoglobulin G; Leukotriene D4; Lung; Male; Mice; Mice, Knockout; Pulmonary Eosinophilia

Inhaled heparin has been shown to inhibit allergic bronchoconstriction in sheep that develop only acute responses to antigen (acute responders) but was ineffective in sheep that develop both acute and late airway responses (LAR) (dual responders). Because the antiallergic activity of heparin is molecular-weight dependent, we hypothesized that heparin-derived oligosaccharides (<2, 500) with potential anti-inflammatory activity may attenuate the LAR in the dual-responder sheep. Specific lung resistance was measured in 24 dual-responder sheep before and serially for 8 h after challenge with Ascaris suum antigen for demonstration of early airway response (EAR) and LAR, without and after treatment with inhaled medium-, low-, and ultralow-molecular-weight (ULMW) heparins and "non-anticoagulant" fractions (NAF) of heparin. Airway responsiveness was estimated before and 24 h postantigen as the cumulative provocating dose of carbachol that increased specific lung resistance by 400%. Only ULMW heparins caused a dose-dependent inhibition of antigen-induced EAR and LAR and postantigen airway hyperresponsiveness (AHR), whereas low- and medium-molecular-weight heparins were ineffective. The effects of ULMW heparin and ULMW NAF-heparin were comparable and inhibited the LAR and AHR even when administered "after" the antigen challenge. The ULMW NAF-heparin failed to inhibit the bronchoconstrictor response to histamine, carbachol, and leukotriene D(4), excluding a direct effect on airway smooth muscle. In six sheep, segmental antigen challenge caused a marked increase in bronchoalveolar lavage histamine, which was not prevented by inhaled ULMW NAF-heparin. The results of this study in the dual-responder sheep demonstrate that 1) the antiallergic activity of inhaled "fractionated" heparins is molecular-weight dependent, 2) only ULMW heparins inhibit the antigen-induced EAR and LAR and postantigen AHR, and 3) the antiallergic activity is mediated by nonanticoagulant fractions and resides in the ULMW chains of <2,500.

Topics: Administration, Inhalation; Airway Resistance; Animals; Antigens; Bronchial Hyperreactivity; Bronchoconstriction; Carbachol; Cholinergic Agonists; Dose-Response Relationship, Drug; Female; Heparin; Histamine; Hypersensitivity; Leukotriene D4; Molecular Weight; Oligosaccharides; Sheep; Time Factors

Although eotaxin causes selective infiltration of eosinophils into the lung, its role in airway hyperresponsiveness remains unclear. We studied the effects of local administration of eotaxin on airway inflammation and hyperresponsiveness in guinea pigs in vivo. Airway responsiveness to inhaled histamine and differential cell counts in bronchoalveolar lavage fluid (BALF) were evaluated 12 h, 24 h, 3 d, and 7 d after intratracheal instillation of eotaxin. Significant eosinophilia in BALF was observed between 6 h and 7 d after eotaxin administration. Histologically, eosinophil accumulation was observed in the airways but not in the alveoli. In contrast, eotaxin did not affect airway responsiveness between 12 h and 7 d after its administration. We then studied the effects on airway responsiveness of subthreshold doses of interleukin 5, leukotriene D(4) (LTD(4)), and platelet-activating factor (PAF) combined with eotaxin. Neither interleukin 5 nor LTD(4) affected airway responsiveness. After eotaxin treatment, PAF significantly enhanced airway responsiveness without further increases in eosinophil counts. Eotaxin plus PAF significantly increased in eosinophil peroxidase activity in BALF compared with control and with eotaxin alone. These data indicate that eotaxin alone causes eosinophil accumulation in the airways but not hyperresponsiveness, and that additional factors such as PAF are needed to activate eosinophils for the development of airway hyperresponsiveness.

Topics: Animals; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Chemokine CCL11; Chemokines, CC; Chemotactic Factors, Eosinophil; Cytokines; Eosinophilia; Eosinophils; Guinea Pigs; Interleukin-5; Leukocyte Count; Leukotriene D4; Male; Platelet Activating Factor

Cysteinyl leukotrienes are potent inflammatory molecules playing a major role in asthma. The involvement of these mediators in hypersensitivity in mice is not well known. This study aimed at elucidating their implication by using MK-571, a cysLT(1)receptor antagonist. Mice were sensitized with a suspension of ovalbumin (8 microg) adsorbed to alum (2 mg) and were challenged with an aerosolized ovalbumin solution (0.5%). Inflammatory cell infiltration in the bronchoalveolar lavage (mostly eosinophils) following antigen challenge was inhibited by dexamethasone (0.1, 1 and 5 mg kg(-1)s.c.) and MK-571 (1, 10, 100 mg kg(-1)i.v.) in a dose-dependent manner. Maximal inhibition was 95% with 5 mg kg(-1)dexamethasone and 90% with 100 mg kg(-1)MK-571. When injected together they showed an additive inhibitory effect on eosinophil infiltration. Bronchial hyperreactivity, measured by the increased pulmonary insufflation pressure to carbachol injections, was also inhibited dose-dependently by MK-571. The EC(50)values for carbachol were of 22.39+/-1.12 microg kg(-1)in sensitized and challenged animals that did not receive MK-571 and increased to 43.65+/-1.10, 50.12+/-1.15 and 83.18+/-1.16 microg kg(-1)in animals treated with 1, 10 and 100 mg kg(-1)MK-571 respectively. Lung microvascular leakage (as measured by Evans blue extravasation) induced by antigen bronchoprovocation was reduced by 22% after treatment with 10 mg kg(-1)MK-571. All these inhibitory effects of MK-571 suggest a role for leukotriene D(4)in this animal model of allergic asthma.

Topics: Animals; Asthma; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Capillary Permeability; Dexamethasone; Disease Models, Animal; Drug Therapy, Combination; Leukotriene Antagonists; Leukotriene D4; Male; Membrane Proteins; Mice; Mice, Inbred BALB C; Ovalbumin; Propionates; Pulmonary Eosinophilia; Quinolines; Receptors, Leukotriene

The effects of 7-[3-[4-(2-quinolinylmethyl)- 1-piperazinyl]propoxy]-2,3-dihydro-4H-1,4- benzothiazin-3-one (VUF-K-8788) on experimental asthmatic reactions in guinea pigs were investigated. VUF-K-8788 inhibited histamine-induced bronchoconstriction at the doses of 0.3 and 1 mg/kg per os (p.o.). VUF-K-8788 inhibited anaphylactic bronchoconstriction at doses between 0.01 and 1 mg/kg in passively sensitized guinea pigs. Terfenadine used as a reference drug also inhibited an antigen-induced bronchoconstriction. VUF-K-8788 at the doses of 0.3 and 1 mg/kg inhibited immediate- and late-phase asthmathic reactions in actively sensitized guinea pigs. Terfenadine inhibited only the immediate phase reaction. Moreover, VUF-K-8788 inhibited the infiltration of eosinophils and macrophages into bronchoalveolar lavage fluid in guinea pigs. These results indicate that VUF-K-8788 may be useful for the treatment of bronchial asthma.

Topics: Airway Resistance; Anaphylaxis; Animals; Anti-Allergic Agents; Anti-Asthmatic Agents; Antigens; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Electric Stimulation; Guinea Pigs; Histamine; Hypersensitivity, Delayed; Hypersensitivity, Immediate; Immunization, Passive; In Vitro Techniques; Leukotriene D4; Male; Piperazines; Thiazines

In guinea pigs, a marked increase in airway responsiveness to acetylcholine (Ach) was observed at 2 h after lipopolysaccharide (LPS) inhalation. To examine the mediators responsible for the airway hyperresponsiveness, the changes of peptide-leukotrienes (LTs), tumor necrosis factor (TNF), interleukin-1 (IL-1), histamine and 5-hydroxytryptamine (5-HT) levels in bronchoalveolar lavage fluid (BALF) were measured. Airway responsiveness to Ach reached a peak 2 h after LPS inhalation. The influx of neutrophil into BALF increased gradually and reached a peak 24 h after LPS inhalation. After the inhalation of LPS, LTD4 and TNF contents in BALF increased within the first 2 h after LPS inhalation. However, other mediators were not detected or increased 6 h after LPS inhalation. Aeroinhalation of LTD4 and murine recombinant TNF-alpha caused airway hyperresponsiveness in guinea pigs. In addition, a LTD4 antagonist, BAYx7195, and an inhibitor of TNF, pentoxifylline, inhibited the LPS-induced airway hyperresponsiveness. These results suggest that LTs and/or TNF play an important role in the onset of airway hyperresponsiveness in guinea pigs.

Topics: Acetylcholine; Animals; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Bronchoconstriction; Escherichia coli; Guinea Pigs; Histamine; Hydroxy Acids; Interleukin-1; Leukotriene D4; Lipopolysaccharides; Male; Pentoxifylline; Recombinant Proteins; Serotonin; Tumor Necrosis Factor-alpha

(+/-)-4-(2-Chlorophenyl)-2-[2-(4-isobutylphenyl)ethyl]-6,9-dime thy l-6H- thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine (Y-24180) is a platelet-activating factor (PAF) antagonist, being similar to WEB 2086. One of the structural differences between the two PAF antagonists is the presence of a methyl substituent in Y-24180 at the 6-position of its ring system. Orally administered Y-24180 and WEB 2086 both dose-dependently prevented PAF-induced airway hyperresponsiveness (ED50: 0.0010 and 0.019 mg/ kg, respectively) and bronchoconstriction (ED50: 0.0014 and 0.024 mg/kg, respectively) in guinea pigs. Against the bronchoconstriction, here, the inhibitory effect of Y-24180 was significantly more potent and longer acting than that of WEB 2086. On the other hand, Y-24180 (10 mg/kg, p.o.) showed insignificant effects on the bronchoconstriction induced by leukotriene D4, histamine, serotonin, acetylcholine, arachidonic acid, or bradykinin. In an in vitro test, Y-24180 and WEB 2086 inhibited the PAF-induced aggregation of the rabbit washed platelets in a concentration-dependent manner (IC50: 1.2 and 64 nmol/l, respectively). Compared with desmethyl-Y-24180 and WEB 2086, Y-24180 and methyl-WEB 2086, both of which have a methyl substituent on the 6-position of their thienodiazepine ring, exhibited a longer acting suppressive effect on PAF-induced bronchoconstriction and significantly more stable binding to the PAF receptor after the washing-out procedure of the test compounds from platelets. Therefore, the 6-methyl substituent should be responsible for the PAF receptor binding stability of Y-24180, namely, for its long-acting anti-PAF effects in vivo. These results indicate that Y-24180 possesses the specific and long-acting PAF antagonistic effects in the airway.

Topics: Acetylcholine; Administration, Oral; Animals; Azepines; Binding Sites; Blood Platelets; Bradykinin; Bronchial Hyperreactivity; Bronchoconstriction; Dose-Response Relationship, Drug; Guinea Pigs; Histamine; Injections, Intravenous; Leukotriene D4; Male; Platelet Activating Factor; Platelet Aggregation Inhibitors; Platelet Membrane Glycoproteins; Rabbits; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Serotonin; Structure-Activity Relationship; Triazoles

We studied the effect of a new antiallergic compound, TYB-2285 (3,5-bis(acetoxyacetylamino)-4-chlorobenzonitrile), on antigen-induced early and late bronchoconstriction and airway responsiveness in conscious allergic sheep. The same general protocol was used for all studies, except that the dosage and time of TYB-2285 treatment was varied. The basic protocol consisted of determining airway responsiveness to inhaled carbachol, then measuring the airway responses to Ascaris suum antigen challenge followed 1 day later by a post challenge assessment of airway responsiveness. Specific lung resistance (SRL) was used to measure the airway responses to antigen and carbachol and the concentration of carbachol that caused a 400% increase in SRL (PC400) was used as a measure of airway responsiveness. All protocols were of crossover design, such that each sheep served as its own control and each protocol employed six to eight animals. In all instances, TYB-2285 or vehicle control (methylcellulose) was given orally. When TYB-2285 (100 mg/kg) was given at 16 and 2 h before the challenge, the early response, the late response and the post antigen-induced airway hyperresponsiveness (AHR) as indicated by a decrease in the PC400 was inhibited significantly. TYB-2285 (100 mg/kg), when given 1 h after challenge, inhibited the late response and AHR significantly. TYB-2285 (100 mg/kg), when given 8 h after the challenge, also inhibited the antigen-induced AHR. When animals were given TYB-2285 (100 mg/kg) at 32, 56 and 80 h after the challenge, the antigen-induced AHR that persisted (for 1 week) in the control trial was reversed to the normal level. TYB-2285 (30 mg/kg), when given at 1, 32, 56 and 80 h after the challenge, inhibited late response slightly and reversed the persistent AHR to the normal level. At lower doses (3 and 10 mg/kg) there was no protection of the early response, the late response or AHR. Pretreatment with TYB-2285 (100 mg/kg) also prevented the antigen-induced influx of eosinophils in bronchoalveolar lavage obtained 24 h after segmental antigen challenge. TYB-2285 did not inhibit histamine or LTD4-induced bronchoconstriction nor did the active metabolites of TYB-2285, TC-286 and TC-326 inhibit acetylcholine-induced contraction of sheep tracheal smooth muscle. These results suggest that TYB-2285 has both antiallergic and antiinflammatory properties in the sheep model of allergic bronchoconstriction. The compound demonstrates both prophylactic and therapeut

Topics: Animals; Asthma; Bronchi; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Bronchoconstrictor Agents; Cross-Over Studies; Eosinophils; Histamine; Leukotriene D4; Nitriles; Sheep; Trachea

We examined whether lipid mediators have a causal role in neonatal hyperoxia-induced lung damage, specifically, airway remodeling and hyperresponsiveness. Newborn rat pups were exposed to hyperoxia (> 95% O2 from Days 4 to 14 and 65% from Days 14 to 32) or normoxia. The 5-lipoxygenase inhibitor, LTD4 receptor antagonist, and inhibitor of platelet-activating factor synthesis, Wy-50,295 (30 mg/kg), or vehicle was administered daily from Days 3 to 32. Oxygen exposure significantly increased (p < 0.05) the production of one potential lipid mediator group, peptido-LTs, from explanted lung slices and large airways from 2-wk-old rat pups. At 4 wk, only the large airway tissue output showed significant elevation because of oxygen exposure. At both ages, Wy-50,295 significantly decreased (p < 0.05) the production of peptido-LTs in the lung and large airways of oxygen-exposed pups. Pulmonary function and airway wall morphometry were studied in 5-wk-old rat pups 2 to 3 d after oxygen exposure and drug administration ceased. The resistance change in response to methacholine (0 to 20 microg/kg body weight given intravenously) was greater (p < 0.02) in oxygen-exposed animals. Oxygen exposure caused significant (60% increase) smooth muscle thickening (p < 0.05). Wy-50,295 prevented the oxygen-induced airway hyperresponsiveness and smooth muscle thickening. We conclude that chronic hyperoxic exposure causes an increase in pulmonary production of at least one lipid mediator, peptido-LTs, from newborn rats and that this is associated with airway smooth muscle layer thickening and, consequently, airway hyperresponsiveness.

Topics: Animals; Animals, Newborn; Bronchi; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchopulmonary Dysplasia; Humans; Infant, Newborn; Leukotriene C4; Leukotriene D4; Leukotriene E4; Lipoxygenase Inhibitors; Muscle, Smooth; Naphthaleneacetic Acids; Oxygen; Quinolines; Rats; Rats, Sprague-Dawley

Antigen-stimulated contraction and release of chemical mediators were examined in saline- or Sephadex-treated rat lung parenchymal strips. Sephadex treatment caused eosinophilia in the blood and the lung tissue. Antigen challenge of the isolated parenchymal strips in Sephadex-treated rat was followed by passive sensitization, resulted in an augmented contraction and elevated releases of thromboxane (TX) B2 and peptide-leukotrienes (p-LTs) in bath fluid compared with those of saline-treated control. Although 5-hydroxytryptamine (5-HT) and histamine were significantly released after antigen challenge, the levels were not different between saline- and Sephadex-treated groups. DP-1904, a selective thromboxane synthetase inhibitor, and methysergide but not atropine significantly reduced the augmented contraction and inhibited the elevated TXB2 release in the Sephadex-treated group. Similar increased contraction and the elevated TXB2 release above were observed when Sephadex-treated rat lung strips were stimulated by exogenous 5-HT and LTD4. These augmented contractions were closely correlated with the increase in TXB2 level (r = 0.83; p < 0.01). In addition, contraction to U-46619, a thromboxane mimetic, was significantly greater in Sephadex-treated rat lung strips. Our results indicate that the ability of Sephadex-treated rat lung tissue to synthesize newly generated mediators such as TXA2 and p-LTs is increased, and the spasmogenic susceptibility of the lung tissue to TXA2 itself is modified by Sephadex treatment, suggesting these are due to the augmented contraction in an established hyperresponsiveness state induced by Sephadex.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Atropine; Bronchial Hyperreactivity; Dextrans; Dose-Response Relationship, Drug; Imidazoles; Leukotriene D4; Lung; Male; Methysergide; Prostaglandin Endoperoxides, Synthetic; Pulmonary Eosinophilia; Rats; Rats, Sprague-Dawley; Tetrahydronaphthalenes; Thromboxane A2; Vasoconstrictor Agents

We studied the effect of intravenous administration of leukotriene (LT) C4 or LTD4 on airway responsiveness to histamine and airway wall thickening in guinea-pigs. Guinea-pigs were killed and the lungs were fixed in formalin. Slides from paraffin-embedded section of the lungs were stained and the airways that were cut in transverse section were measured by tracing enlarged images using a digitizer. Moreover, airway resistance (Raw) was determined by a pulmonary mechanics analyser and we calculated two indices, an index of airway wall thickening and the one of airway hyperresponsiveness to histamine, from changes of baseline-Raw and peak-Raw following intravenous administration of histamine before and after the intravenous administration of LTC4 or LTD4. The infusion of LTC4 or LTD4 induced an increase of the relative thickness of the airway wall in peripheral bronchi demonstrable by the histological examination. In analysis of airway function, intravenous administration of LTC4 or LTD4 induced airway hyperresponsiveness to histamine with airway wall thickening. The LTC4 and LTD4 receptor antagonist ONO-1078 inhibited these effects of LTC4 and LTD4, suggesting LTC4 and LTD4 may induce airway wall thickening and airway hyperresponsiveness through LTC4 and LTD4 receptors in the airways.

Topics: Airway Resistance; Animals; Bronchial Hyperreactivity; Chromones; Guinea Pigs; Histamine; Image Processing, Computer-Assisted; Infusions, Intravenous; Leukotriene Antagonists; Leukotriene C4; Leukotriene D4; Lung; Male; SRS-A

1. The effect of a single intratracheal dose (10 mg) of PF 5901 (2-[3(1-hydroxyhexyl) phenoxymethyl] quinoline hydrochloride, a specific inhibitor of the 5-lipoxygenase pathway of arachidonic acid metabolism and a leukotriene D4 antagonist) on airway changes induced in response to Alternaria tenuis aerosol challenge was assessed in adult rabbits neonatally immunized. Leukotriene generation was determined in vivo by measuring leukotriene B4 (LTB4) levels in bronchoalveolar lavage (BAL) fluid and ex vivo by measuring calcium ionophore-stimulated production of LTB4 in whole blood. 2. While PF 5901 (10 mg) had no significant effect on the acute bronchoconstriction induced by antigen, this dose was sufficient to inhibit significantly the increase in airway responsiveness to inhaled histamine 24 h following antigen challenge (P < 0.05). 3. Total leucocyte infiltration into the airways induced by antigen, as assessed by bronchoalveolar lavage, was significantly inhibited by pretreatment with PF 5901 (10 mg). However, the pulmonary infiltration of neutrophils and eosinophils induced by antigen was unaltered by prior treatment with PF 5901 (10 mg). 4. PF 5901 (10 mg) had no effect on ex vivo LTB4 synthesis in whole blood. However, the antigen-induced increase in LTB4 levels in BAL 24 h following challenge was significantly inhibited (P < 0.05). 5. We suggest from the results of the present study that the antigen-induced airway hyperresponsiveness to inhaled histamine in immunized rabbits is mediated, at least in part, by products of the 5-lipoxygenase metabolic pathway, and is not dependent on the extent of eosinophil or neutrophil influx into the airway lumen.

Topics: Administration, Inhalation; Airway Resistance; Alternaria; Animals; Animals, Newborn; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Bronchoconstriction; Female; Histamine; Leukotriene B4; Leukotriene D4; Lipoxygenase Inhibitors; Lung; Lung Compliance; Male; Quinolines; Rabbits; Respiratory Function Tests; Respiratory Hypersensitivity