leukotriene-c4 and Bronchial-Hyperreactivity

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

Topics: Asthma; Bronchial Hyperreactivity; Humans; Interleukin-16; Leukotriene C4

Topics: Animals; Arachidonate 5-Lipoxygenase; Asthma; Bronchial Hyperreactivity; Cell Adhesion Molecules; Eosinophils; Humans; Leukotriene C4; Neutrophils

Increased levels of leukotrienes (LTs) in exhaled breath condensate (EBC) are associated with asthma and bronchial hyperresponsiveness (BHR), whereas eicosanoids generated through the 15-lipoxygenase (LO) pathway (15-hydroxyeicosatetraenoic acid [HETE] and eoxins) have been less studied.. We investigated whether metabolites of the 5- and 15-LO pathways in EBC are associated with childhood asthma, asthma severity, and clinical parameters.. The present study included 131 school-aged children (27 children with problematic severe asthma, 80 children with mild-to-moderate asthma, and 24 healthy children) from the Severe Asthma Recognized in Childhood study and 19 children with other nonasthmatic chronic lung diseases. Clinical work-up included spirometry, fractional exhaled nitric oxide measurements, skin prick testing, and methacholine challenge. Eicosanoids were analyzed in EBC by using mass spectrometry and are reported as concentrations (in picograms per milliliter) and eicosanoid/palmitic acid (PA) ratios.. Eoxin C₄/PA, eoxin D₄/PA, eoxin E₄/PA, 15-HETE/PA, and LTC₄/PA ratios were significantly increased in asthmatic versus healthy children. Eoxin D₄/PA and LTE₄/PA ratios were also significantly higher in children with BHR. A nonsignificant trend was observed toward higher eoxin/PA ratios with increasing asthma severity. In contrast to asthma, children with chronic lung disease had the highest 15-HETE/PA, LTC₄/PA, LTE₄/PA, and LTB₄/PA ratios.. The results point to increased activity of the 15-LO inflammatory pathway in childhood asthma. Mass spectrometric analyses of EBC demonstrate that increased eoxin levels not only accompany the increased 5-LO product LTC₄ but are also associated with BHR. These markers might represent a new therapeutic target for asthma treatment.

Topics: Adolescent; Arachidonate 15-Lipoxygenase; Asthma; Breath Tests; Bronchial Hyperreactivity; Child; Exhalation; Female; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Leukotriene C4; Leukotriene E4; Leukotrienes; Male; Mass Spectrometry; Severity of Illness Index

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

CCL28 is a recently identified chemokine ligand for CCR10 and CCR3 that has been identified in mucosal epithelial surfaces in diverse tissues. CCL28-mediated eosinophil chemotaxis and peroxidase release were inhibited by preincubation of cells with anti-CCR3. CCL28 was constitutively expressed in lung tissue collected from nonsensitized control mice but increased levels were found in mice sensitized and rechallenged with cockroach antigen (CRA). CCL28 levels peaked in the lungs 24 hours after intratracheal challenge with CRA, whereas eotaxin expression peaked at 8 hours. Increased expression of CCR3 but not CCR10 could be detected during the induction of the CRA-induced pulmonary inflammation. To investigate the role of CCL28 in allergic airway responses, mice were treated with CCL28 antiserum 1 hour before receiving the final CRA challenge. The level of airway hyperresponsiveness in mice treated with anti-CCL28 was significantly reduced at 24 hours, but not 8 hours, compared to mice receiving control serum. This reduction was not related to decreased Th2 cytokine, chemokine, or leukotriene levels at 24 hours although peribronchial eosinophilia was significantly reduced. Thus, CCL28 appears to play a role in regulating eosinophil recruitment to peribronchial regions of the lung possibly by coordinated temporal production with eotaxin.

Topics: Animals; Bronchial Hyperreactivity; Chemokine CCL11; Chemokines; Chemokines, CC; Chemotaxis; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Eosinophils; Gene Expression Regulation; Immunohistochemistry; Inflammation; Leukotriene C4; Leukotrienes; Ligands; Lung; Mice; Mice, Inbred CBA; Peroxidases; Receptors, CCR10; Receptors, CCR3; Receptors, Chemokine; RNA; Th2 Cells; Time Factors

Smoking is the most important cause of chronic obstructive pulmonary disease (COPD). However, the influence of cigarette smoking on the pathogenesis of asthma in the elderly remains controversial. This study attempted to clarify the influence of cigarette smoking on elderly asthmatics.. Forty-eight asthmatics over 70 years old (25 ex-smokers and 23 never-smokers) and 20 patients with COPD over 70 years old (all ex-smokers) were studied to determine the influence of cigarette smoking on IgE-mediated allergy (total IgE, IgE antibodies against inhalant allergens, bronchial hyper-responsiveness (BHR), generation of leukotriene (LT) B4 and C4), pulmonary function, and the relative area of lung showing attenuation values less than -950 Hounsfield units (RA950) on high-resolution computed tomography scans.. The incidence of positive IgE antibodies against inhalant allergens, BHR, and the generation of leukotriene B4 (LTB4) by leucocytes were significantly increased in patients with a history of smoking compared with those without. Residual volume (%RV) was significantly increased, and diffusing capacity for carbon monoxide was significantly decreased in ex-smokers with asthma and COPD compared with never-smokers with asthma. Inspiratory RA950 and ratio of expiratory RA950 to inspiratory RA950 were significantly larger in asthmatics with a smoking history than in those without, and in COPD patients than in asthmatics.. Cigarette smoking enhances the production of IgE antibodies, BHR, and generation of LTB4 by leucocytes in elderly asthmatics. Increased hyper-inflation or emphysematous changes of the lungs expressed by increased RA950, closely related to %RV, was more frequently observed in ex-smokers compared with never-smokers.

Topics: Aged; Asthma; Bronchial Hyperreactivity; Case-Control Studies; Chi-Square Distribution; Female; Humans; Immunoglobulin E; Leukocytes; Leukotriene B4; Leukotriene C4; Male; Pulmonary Diffusing Capacity; Pulmonary Disease, Chronic Obstructive; Respiratory Function Tests; Smoking; Tomography, X-Ray Computed

In mice, intratracheal challenges with antigen (ovalbumin) or recombinant murine interleukin-13 (IL-13) induce lung inflammation, bronchial hyperreactivity (BHR), and mucus accumulation as independent events (Singer M, Lefort J, and Vargaftig BB. Am J Respir Cell Mol Biol 26: 74-84, 2002), largely mediated by leukotrienes (LT). We previously showed that LTC(4) was released 15 min after ovalbumin, and we show that it induces the expression of monocyte chemoattractant proteins 1 and 5 and KC in the lungs, as well as IL-13 mRNA. Instilled intratracheally, these chemokines induced BHR and mucus accumulation, which were inhibited by the 5-lipoxygenase inhibitor zileuton and by the cysteinyl-LT receptor antagonist MK-571, suggesting mediation by cysteinyl-LT. Because these chemokines also induced release of LT into the bronchoalveolar lavage fluid and IL-13 into the lungs, we hypothesize that LT- and chemokine-based loops for positive-feedback regulations cooperate to maintain and amplify BHR and lung mucus accumulation after allergic challenge and in situations where IL-13, LT, or chemokines are generated.

Topics: Animals; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Chemokines; Hypersensitivity; Interleukin-13; Leukotriene C4; Leukotrienes; Lung; Male; Metaplasia; Mice; Mice, Inbred Strains; Mucins; Mucus; Ovalbumin; Recombinant Proteins; Respiratory Mucosa; RNA, Messenger

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

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 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

Leukotrienes (LTs) are pro-inflammatory mediators that contribute to the pathophysiological features of asthma. The relationship between the amounts of LTB4 and LTC4 produced by the leukocytes of asthmatic patients on the one hand and immunoglobulin E (IgE)-mediated allergy, asthma exacerbations and bronchial hyperresponsiveness was studied. Leukocytes were obtained from peripheral blood drawn from 29 atopic and 27 nonatopic asthmatics during exacerbations and clinically controlled periods, as well as from 20 control individuals. The leukocytes were stimulated with calcium ionophore A23187 to induce LTB4 and LTC4 production. Allergy was assessed by means of specific serum IgE or by positive skin tests, whereas bronchial hyperresponsiveness was measured by methacholine challenge. The leukocytes of the asthmatics generated significantly more LTB4 (p<0.05) and LTC4 (p<0.01) than those of controls. The leukocytes of patients with atopic asthma generated significantly more LTC4 than those of patients with nonatopic asthma (p<0.01). Significantly more LTC4 was produced by leukocytes obtained during exacerbations, than by those obtained during clinically controlled periods (p<0.01). In addition, there was a significant correlation between LTB4 generation by leukocytes and the degree of bronchial hyperresponsiveness to methacholine (r=-0.792, p<0.0001). These results suggest that leukotriene C4 production by leukocytes is associated with immunoglobulin E-mediated allergy and asthma exacerbations, and further that generation of leukotriene B4 is closely related to bronchial hyperresponsiveness in patients with asthma.

Topics: Asthma; Bronchial Hyperreactivity; Female; Humans; Leukocytes; Leukotriene B4; Leukotriene C4; Male; Middle Aged

Hyperresponsiveness of airway smooth muscle accounts for the susceptibility of asthmatic subjects to diverse bronchoconstrictor agents. It is widely presumed that hyperresponsiveness is not spasmogen selective. Hence, inhalation of methacholine is used routinely for clinical assessment of asthma and for evaluation of anti-asthma drugs. Comparative studies employing multiple spasmogens have revealed hyperresponsiveness to be markedly spasmogen selective. Because of this pronounced heterogeneity of hyperresponsiveness, sensitivity to methacholine cannot provide a reliable index of responsiveness. Development of exceptional hyperresponsiveness to bradykinin and to peptidoleukotrienes during allergic and other reactions could warrant the development of specific antagonists for asthma therapy. These issues are discussed here by Brian O'Connor, Simon Crowther, John Costello and John Morley.

Topics: Albuterol; Animals; Asthma; Bradykinin; Bronchial Hyperreactivity; Bronchoconstrictor Agents; Bronchodilator Agents; Humans; Leukotriene C4; Methacholine Chloride

Bronchial eosinophil and mononuclear cell infiltrates are a hallmark of the asthmatic lung and are associated with the induction of reversible airway hyperreactivity. In these studies, we have found that monocyte chemotactic protein-1 (MCP-1), a CC (beta) chemokine, mediates airway hyperreactivity in normal and allergic mice. Using a murine model of cockroach Ag-induced allergic airway inflammation, we have demonstrated that anti-MCP-1 Abs inhibit changes in airway resistance and attenuate histamine release into the bronchoalveolar lavage, suggesting a role for MCP-1 in mast cell degranulation. In normal mice, instillation of MCP-1 induced prolonged airway hyperreactivity and histamine release. In addition, MCP-1 directly induced pulmonary mast cell degranulation in vitro. These latter effects would appear to be selective because no changes were observed when macrophage-inflammatory protein-1alpha, eotaxin, or MCP-3 were instilled into the airways of normal mice or when mast cells were treated in vitro. Airway hyperreactivity was mediated by MCP-1 through CCR2 because allergen-induced as well as direct MCP-1 instilled-induced changes in airway hyperreactivity were significantly attenuated in CCR2 -/- mice. The neutralization of MCP-1 in allergic animals and instillation of MCP-1 in normal animals was related to leukotriene C4 levels in the bronchoalveolar lavage and was directly induced in pulmonary mast cells by MCP-1. Thus, these data identify MCP-1 and CCR2 as potentially important therapeutic targets for the treatment of hyperreactive airway disease.

Topics: Administration, Intranasal; Airway Resistance; Allergens; Animals; Bronchial Hyperreactivity; Cells, Cultured; Chemokine CCL2; Cockroaches; Female; Histamine Release; Immunization, Secondary; Injections, Intraperitoneal; Intubation, Intratracheal; Leukotriene C4; Mast Cells; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Knockout; Receptors, CCR2; Receptors, Chemokine; Receptors, Cytokine

A novel series of 2,2-dialkyl-5-(2-quinolylmethoxy)-1,2,3, 4-tetrahydro-1-naphthols was synthesized and evaluated as 5-lipoxygenase (5-LO) inhibitors. Systematic optimization led to identification of several highly potent non-redox type 5-LO inhibitors with nanomolar IC50s as racemic mixtures. Optical resolution of racemate 50 indicated that its 5-LO inhibitory activity was enantiospecific and due to the (+)-enantiomer. An efficient synthetic route to the (+)-enantiomers via asymmetric reduction of tetralone intermediates was established. The best compound, (+)-2,2-dibutyl-5-(2-quinolylmethoxy)-1,2,3,4-tetrahydro-1-naphtho l (FR110302, (+)-50), showed potent inhibitory activity against leukotriene (LT) biosynthesis by intact neutrophiles in rats (IC50 4.9 nM) and in humans (IC50 40 nM). Furthermore oral administration of FR110302 significantly inhibited neutrophil migration in the rat air pouch model at 1 mg/kg.

Topics: Anaphylaxis; Animals; Blood Platelets; Bronchial Hyperreactivity; Humans; Hydroxyeicosatetraenoic Acids; In Vitro Techniques; Leukotriene C4; Lipoxygenase Inhibitors; Male; Naphthols; Neutrophils; Optical Rotation; Quinolines; Rats; Rats, Sprague-Dawley; SRS-A; Stereoisomerism

There is currently interest in the use of inhibitors of cyclic nucleotide phosphodiesterases (PDE) as potential anti-asthma agents. In this study we examined the effects of SCA40 (6-bromo-8-methylaminoimidazol-[1,2-a] pyrazine-2-carbonitrile), a preferential inhibitor of PDE 3 also endowed with PDE 4 and 5 inhibitory activities, on isolated bronchus and eosinophil functions and in an animal model of asthma. SCA40 (1 nM-0.1 mM) produced concentration-dependent inhibition of spontaneous and stimulated tone of human isolated bronchus and reached a maximal relaxation similar to that of theophylline (3 mM). The potency (-log EC50 values) of SCA40 against spontaneous tone (6.52 +/- 0.10) was greater than against tone raised by equieffective concentrations (approximately 70%) of histamine (5.76 +/- 0.06), leukotriene C4 (5.44 +/- 0.11), and acetylcholine (4.98 +/- 0.09). In the presence of cytochalasin B, the chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP; 0.5 microM) induced leukotriene C4 production in human eosinophils isolated in discontinuous metrizamide gradients. The production of leukotriene C4 was inhibited by SCA40 in a concentration-related fashion (-log IC50 = 6.04 +/- 0.20; n = 6). Rolipram, a selective PDE 4 inhibitor, was also effective (-log IC50 = 7.29 +/- 0.32) but the selective PDE 3 inhibitor SKF94120 was scarcely effective (< 10% inhibition for 10 microM). In ovalbumin sensitized guinea-pigs, SCA40 (1 mg kg(-1), i.p.) given 30 min before antigen challenge significantly inhibited the acute bronchoconstriction produced by aerosol antigen (5 mg ml(-1), 30 s) (antigen response was 185 +/- 13 and 91 +/- 21 cmH2O l(-1) s(-1) in control and SCA40-treated animals, respectively, P < 0.05). Pretreatment with SCA40 (1 mg kg(-1), i.p., 30 min pre- and 3 h post-antigen exposure) prevented airway hyperreactivity to histamine which developed 24 h after exposure of conscious guinea-pigs to aerosol antigen. Eosinophil lung accumulation that accompanied airway hyperreactivity was also inhibited by SCA40 (from 6.15 +/- 0.86 in control to 1.27 +/- 0.27 in treated animals; expressed as eosinophils x 10(6); P < 0.05). SCA40 (1 mg kg(-1), i.p.) also inhibited the microvascular leakage produced after inhaled antigen (5 mg ml(-1), 30 s) at all airway levels. The haemodynamic effects of SCA40 (1 mg kg(-1), i.p.) consisted of a rapid decrease (peak at 5 min) in mean arterial blood pressure (-39.4 +/- 2.4%) and tracheal mucosal blood flow (-13.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antigens; Bronchi; Bronchial Hyperreactivity; Bronchodilator Agents; Eosinophils; Guinea Pigs; Humans; Imidazoles; In Vitro Techniques; Leukotriene C4; Muscle Relaxation; Muscle, Smooth; Pyrazines

To elucidate the mechanism of development of asthma, we tried to develop a model which elicited a late asthmatic response by a combination of systemic and inhaled sensitization with ovalbumin in guinea pigs. Eighty-seven percent of animals elicited both an immediate and late asthmatic response after the third antigen inhalation. Airway eosinophilia and airway hyperresponsiveness (AHR) induced after the third challenge were more severe than those after the first challenge. There was a good correlation between airway eosinophilia and AHR in this model under experimental modulation of the number of eosinophils, such as by interleukin 5 or antieosinophil antibody injection. These results demonstrate that eosinophils play an important role in the development of late asthmatic response and AHR.

Topics: Animals; Antibodies; Asthma; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Bronchoconstrictor Agents; Disease Models, Animal; Eosinophils; Guinea Pigs; Histamine; Interleukin-5; Leukocyte Count; Leukotriene C4; Male; Methacholine Chloride; Ovalbumin; Passive Cutaneous Anaphylaxis; Pulmonary Eosinophilia; Thromboxane B2; Time Factors

Topics: Aerosols; Albuterol; Animals; Bronchial Hyperreactivity; Dose-Response Relationship, Drug; Female; Guinea Pigs; Histamine; Immune Sera; Immunization, Passive; Leukotriene C4; Ovalbumin; Stereoisomerism

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

To assess the relation among eosinophil-related variables in the peripheral blood, bronchial hyperreactivity, and the presence of atopic dermatitis in children aged 5-14 years, we studied 11 patients with atopic dermatitis alone, six with asthma and atopic dermatitis, 12 with asthma alone, and 12 healthy controls. Eosinophil counts, levels of eosinophil cationic protein, and the capacity of eosinophils to generate leukotriene (LT) C4, as well as bronchial hyperreactivity and a severity score for atopic dermatitis, were determined. Eosinophil variables were significantly higher in both patient groups with atopic dermatitis than in normal controls. In particular, ionophore A 23187 LTC4 generation was higher in patients with atopic dermatitis alone (median 82, range 25-273 ng/10(6) cells) and patients with combined asthma and atopic dermatitis (median 68, range 32-583 ng/10(6) cells) than in normal controls (median 9, range 1-67 ng/10(6) cells). However, there was no difference between the group of atopic dermatitis patients with asthma and without asthma. We conclude that eosinophil variables in the peripheral blood are mainly influenced by the presence of atopic dermatitis, and not the presence and the severity of asthma in patients with both asthma and atopic dermatitis.

Topics: Adolescent; Asthma; Blood Proteins; Bronchial Hyperreactivity; Child; Child, Preschool; Dermatitis, Atopic; Eosinophil Granule Proteins; Eosinophils; Female; Humans; Immunoglobulin E; Inflammation Mediators; Leukocyte Count; Leukotriene C4; Male; Ribonucleases

To determine whether nasal allergic symptoms can cause bronchial hyperresponsiveness to methacholine, 30 subjects with allergic rhinitis (22 with allergic rhinitis and 8 with allergic asthmatic rhinitis) were studied. All subjects were skin test positive to Dermatophagoides pteronyssinus (DP) and underwent nasal allergic provocation with DP. After provocation, there was a severe nasal allergic reaction in the challenged nostril with a significant increase in nasal resistance both immediately and long (7 h) after DP exposure. There were no significant changes in the forced expiratory volume in 1 s and the forced expiratory flow rate between 25 and 75% of the forced vital capacity and in both allergic rhinitis and allergic asthmatic rhinitis patients. There was also no change in bronchial hyperresponsiveness to methacholine. The eosinophil counts, leukotriene B4, leukotriene C4 and platelet-activating factor levels in nasal discharges also showed no differences in both groups of patients. Our studies suggest that nasal provocation with limited allergen is a safe diagnostic technique. However, the relationship between nasal resistance and airway hyperreactivity is not obvious in this study. The similar concentrations of nasal inflammatory mediators in both allergic rhinitis and allergic asthmatic rhinitis indicate that bronchial hyperreactivity is not solely due to nasal drainage of inflammatory mediators.

Topics: Adolescent; Adult; Allergens; Antigens, Dermatophagoides; Bronchial Hyperreactivity; Eosinophils; Female; Glycoproteins; Humans; Leukocyte Count; Leukotriene B4; Leukotriene C4; Male; Methacholine Chloride; Nasal Mucosa; Nasal Provocation Tests; Platelet Activating Factor; Rhinitis, Allergic, Perennial

Infants born prematurely are known to display longstanding bronchial hyperreactivity. The mechanism responsible for this is still unclear. Eosinophils are thought to play a central part in the development of bronchial hyperreactivity in asthma. It was the aim of this study to assess the relation of bronchial hyperresponsiveness to potential markers of eosinophilic inflammation in peripheral blood. Eosinophil count, the concentration of serum eosinophilic cationic protein, the capacity of purified eosinophils to generate leukotriene C4, and bronchial reactivity was studied in 24 non-atopic children born prematurely, 12 healthy controls, and 12 children with asthma aged 6 to 9 years. There was no difference in serum concentrations on eosinophil cationic protein and eosinophil counts. However, eosinophils from the 15 formerly preterm infants with significant bronchial hyperreactivity generated significantly higher amounts of leukotriene C4 than normal controls and prematurely born children without bronchial hyperreactivity. Levels of leukotriene C4 in this group were comparable with those obtained with eosinophils from patients with asthma. In contrast with cells from the other groups, eosinophils from the children with bronchial hyperreactivity born prematurely show no enhancement of leukotriene C4 generation on prestimulation with platelet activating factor. It is concluded that bronchial hyperreactivity of children born prematurely is accompanied by the prestimulation of eosinophils.

Topics: Asthma; Bronchial Hyperreactivity; Child; Eosinophils; Forced Expiratory Volume; Humans; Infant, Newborn; Infant, Premature; Leukocyte Count; Leukotriene C4; Vital Capacity

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

We studied the effect of i.v.administration of leukotriene (LT) C4 on bronchial responsiveness to histamine and airway wall thickening in guinea-pigs. The infusion of 3 micrograms/kg LTC4 for 1 h induced an increase of the relative thickness of the airway wall in peripheral bronchi, found by histological examination. In analysis of airway function, the infusion of 3 micrograms/kg LTC4 for 1 h induced airway wall thickening and airway hyperresponsiveness to histamine administered i.v.at doses of 1.8 and 3.6 micrograms/kg. Thromboxane A2 synthetase inhibitor OKY-046, which was administered perorally, inhibited the LTC4-induced airway hyperresponsiveness to histamine in a dose-dependent manner at doses from 30-100 mg/kg, but not the airway wall thickening induced by LTC4.

Topics: Airway Resistance; Animals; Bronchi; Bronchial Hyperreactivity; Guinea Pigs; Histamine; Histamine Antagonists; Injections, Intravenous; Leukotriene C4; Male; Methacrylates; Thromboxane-A Synthase

We studied the effect of intravenous administration of leukotriene (LT) C4 on bronchial 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 sections of the lungs were stained and the airways that were cut in transverse sections 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. Intravenous administration of 3 microg/kg LTC4 for 1 hr induced an increase of the relative thickness of the airway wall in peripheral bronchi by the histological examination. In analysis of airway function, intravenous administration of 3 microg/kg LTC4 for 1 hr induced airway hyperresponsiveness to histamine with airway wall thickening. Thromboxane A2 receptor antagonists ONO-NT-126 and ONO-8809 inhibited the LTC4-induced airway hyperresponsiveness to histamine in a dose-dependent manner, but not the airway wall thickening induced by LTC4, suggesting that the effect of LTC4 on bronchial hyperresponsiveness is likely to be mediated through TXA2.

Topics: Airway Resistance; Animals; Bridged Bicyclo Compounds; Bronchi; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoconstrictor Agents; Dose-Response Relationship, Immunologic; Edema; Fatty Acids, Monounsaturated; Guinea Pigs; Histamine; Injections, Intravenous; Leukotriene C4; Male; Molecular Structure; Receptors, Thromboxane