s-145 and Asthma

Lung tissues produce a large amount of Thromboxane (Tx) A2. In addition to platelet aggregation and artery smooth muscle contraction, TxA2 strongly induces airway smooth muscle contraction and bronchial hyperresponsiveness. Not only TxA2, but many arachidonate cyclooxygenase metabolites such as PGD2, PGF2 alpha, PGH2, and others stimulate TP (PGH2/TxA2) receptor and can take a pathophysiological role for bronchial asthma. Several compounds competitively antagonizing TP receptor have been developed and being proved to have beneficial effects for treating of bronchial asthma in clinical. In this review the efficacy and usage of TP receptor antagonists for bronchial asthma was discussed.

Topics: Asthma; Benzoquinones; Bridged Bicyclo Compounds; Bronchi; Bronchial Hyperreactivity; Carbazoles; Fatty Acids, Monounsaturated; Heptanoic Acids; Humans; Prostaglandins; Receptors, Thromboxane; Sulfonamides; Thromboxane A2

It has been considered that thromboxane A2 (TXA2) is involved in the development of bronchial hyperresponsiveness (BHR), a characteristic feature of asthma. To ensure the involvement of TXA2 in BHR of asthma, effects of a 1-week treatment with two orally active TXA2 antagonists, BAY u 3405 and S-1452, on BHR were examined in 10 and 13 patients with stable asthma, respectively, in two consecutive double-blinded, randomized, placebo-controlled, two-phase crossover studies. Provocative concentration of methacholine causing a 20% fall in FEV1 (PC20-FEV1) with BAY u 3405 (0.78 (GSEM, 1.50) mg/ml) was significantly greater than the value with placebo (0.65 (GSEM, 1.46) mg/ml) (ratio 1.23 times, 95% CI 1.01 to 1.46: P = 0.0401). PC20-FEV1 was also significantly increased with S-1452 (0.43 (GSEM, 1.39) mg/ml) compared with placebo (0.29 (GSEM, 1.27) mg/ml) (ratio 1.75 times, 95% CI 1.05 to 2.45: P = 0.0189). Baseline pulmonary function was not altered by these treatments. These results may ensure that TXA2 is significantly involved in the BHR of asthma while the degree of contribution may be small.

Topics: Adolescent; Adult; Airway Resistance; Asthma; Bridged Bicyclo Compounds; Bronchial Hyperreactivity; Bronchoconstrictor Agents; Carbazoles; Cross-Over Studies; Double-Blind Method; Fatty Acids, Monounsaturated; Female; Forced Expiratory Volume; Humans; Male; Methacholine Chloride; Middle Aged; Prostaglandin Antagonists; Sulfonamides; Thromboxane A2

Thromboxane (Tx)A2 synthase inhibitors and thromboxane prostanoid (TP) receptor antagonists have been developed as anti-asthma drugs. TxA2 may contribute to airflow limitation and bronchial hyperresponsiveness, and these compounds have been demonstrated to improve them. However, it is not known whether TxA2 is involved in bronchial inflammation. To address this question, we explored the influences of OKY-046 (a TxA2 synthase inhibitor) and S-1452 (a TP receptor antagonist) on eosinophilic inflammation of the airways using a murine model. BALB/c mice sensitized with ovalbumin and challenged by repeated exposure to ovalbumin yielded marked eosinophilia in bronchoalveolar lavage fluid (BALF). Treatment with either compound significantly reduced the number of total cells and eosinophils in BALF in a dose-dependent manner. The production of interleukin (IL)-5, IL-2 and interferon (IFN)-gamma by antigen-stimulated splenic mononuclear cells (SMNC) was significantly decreased in mice treated with either compound compared to that in untreated mice. Furthermore, both compounds inhibited proliferation and cytokine production of SMNC in vitro. These results suggest that both OKY-046 and S-1452 are capable of inhibiting production of cytokines, which in turn inhibits eosinophil infiltration into the murine airway. Thus, both thromboxane A2 synthesis inhibitors and thromboxane prostanoid antagonists may be effective as anti-inflammatory drugs in the treatment of asthma.

Topics: Animals; Asthma; Bridged Bicyclo Compounds; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Cytokines; Enzyme Inhibitors; Fatty Acids, Monounsaturated; Methacrylates; Mice; Mice, Inbred BALB C; Prostaglandin Antagonists; Pulmonary Eosinophilia; Thromboxane-A Synthase

To investigate the mechanisms of airway hyperresponsiveness (AHR), we examined the time course for asthmatic responses (including immediate asthmatic response (IAR), late asthmatic response (LAR), and AHR), airway inflammation (including edema in the airway, accumulation of inflammatory cells in bronchoalveolar lavage fluid (BALF), and mediator release including histamine and thromboxane A2 (TXA2) in BALF after the repeated provocation of aeroantigen in sensitized guinea pigs. Furthermore, we examined the effect of S-1452, a TXA2 receptor antagonist, on the antigen-induced airway obstruction and AHR in guinea pigs. We found that IAR occurred 1 min after every antigen inhalations. LAR was observed every 4 h after the inhalation of antigen without 1st or 2nd challenge. AHR was initially observed 4 h after the 5th inhalation of antigen, and then AHR was observed at every time measured even after the 6th provocation. The water content of the airway increased after the 2nd antigen inhalation. A number of leukocytes, especially eosinophils in BALF, was observed 30 min after the 2nd antigen inhalation. Desquamation of epithelia was observed 30 min after the 5th antigen inhalation. TXB2 and histamine in BALF were detected after the first antigen inhalation. These results suggest that LAR is caused by repeated airway inflammation such as eosinophilia and mediator release including TXA2. AHR may appear with the damages of lung tissue such as desquamation of epithelia. Oral administration of S-1452 (1 and 10 mg/kg) significantly inhibited LAR and AHR, assessed after the 6th antigen challenge. The present findings suggest that repeated antigen challenge causes airway inflammation and leads to the onset of LAR and AHR when became chronic. Furthermore, persistent generated TXA2 plays an important role in the pathogenesis of antigen-induced late-phase obstruction and AHR.

Topics: Airway Obstruction; Airway Resistance; Animals; Antigens; Asthma; Bridged Bicyclo Compounds; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchitis; Bronchoalveolar Lavage Fluid; Fatty Acids, Monounsaturated; Guinea Pigs; Histamine; Male; Prostaglandin Antagonists; Pulmonary Edema; Thromboxane B2; Time Factors

Membrane-derived lipid mediators have been considered to play a major role in pathogenesis of bronchial asthma. However, the importance of and the interactions among each mediator are still unclear. We examined the role of thromboxane A2 (TXA2) and platelet-activating factor (PAF) in immediate asthmatic response (IAR) and interactions between these lipid mediators in guinea pig airway in vivo using a specific TXA2 antagonist S-1452 and a specific PAF antagonist Y-24180. We confirmed the activity of each antagonist, as S-1452 and Y-24180 significantly and dose-dependently inhibited bronchoconstriction induced by respective agonist inhalation. S-1452 inhibited IAR but Y-24180 did not, indicating that TXA2 plays a major role in IAR but PAF does not. S-1452 significantly inhibited PAF-induced bronchoconstriction but Y-24180 did not inhibit synthesized TXA2 (STA2)-induced bronchoconstriction, showing that the bronchoconstrictive effect of PAF is at least in part dependent on secondarily released TXA2, but TXA2 does not induce PAF production.

Topics: Administration, Inhalation; Animals; Antigens; Asthma; Azepines; Bridged Bicyclo Compounds; Bronchoconstriction; Dose-Response Relationship, Drug; Fatty Acids, Monounsaturated; Guinea Pigs; Hypersensitivity; Male; Platelet Activating Factor; Receptors, Prostaglandin; Thromboxane A2; Triazoles

Interleukin-8 (IL-8) has been shown to be a chemotactic factor for neutrophils, T-lymphocytes and eosinophils, but it is unknown whether the IL-8-induced inflammatory cell accumulation into the airways can cause the bronchial hyperresponsiveness (BHR) characteristic of asthma. IL-8 at a dose of 0.5 or 5 micrograms/kg was administered intranasally to guinea-pigs twice a week for 3 weeks. One day after the last administration, animals were anesthetized and artificially ventilated through tracheal cannula and lateral pressure at the cannula (Pao) was measured as an overall index of airway responses to increasing concentrations of inhaled histamine (25, 50, 100, and 200 micrograms/ml). The IL-8 treatment significantly enhanced bronchial responsiveness to histamine in a dose-dependent manner (ANOVA P < 0.01). The provocative concentration of histamine causing a 100% increase in Pao (PC100) at a dose of 0.5 and 5 micrograms/kg of IL-8 was 68.1 (GSEM 1.12) and 35.6 (GSEM 1.25) micrograms/ml, respectively. The latter was significantly (P < 0.01) lower than that in control animals treated with PBS (93.3 [GSEM, 1.14] micrograms/ml). The IL-8 treatment also induced a significant influx of neutrophils, but not eosinophils, in bronchoalveolar lavage (BAL) fluid (18.3 +/- 8.8 and 30.6 +/- 8.3% in animals treated with 0.5 and 5 micrograms/kg, respectively, of IL-8 vs 3.6 +/- 0.7% in phosphate buffered saline-(PBS)-treated animals). Furthermore, we examined the effect of the thromboxane receptor antagonist S-1452 (0.01 or 0.1 mg/kg, i.p. 24 and 1 h before anesthesia) on this IL-8 induced BHR. S-1452 significantly inhibited the BHR dose-dependently (ANOVA P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Administration, Intranasal; Animals; Asthma; Bridged Bicyclo Compounds; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Fatty Acids, Monounsaturated; Guinea Pigs; Interleukin-8; Male; Neutrophils; Receptors, Prostaglandin; Thromboxane A2

The importance of thromboxane A2 (TXA2), one of the arachidonate metabolites, in the pathogenesis of bronchial asthma has been emphasized recently. Because aerosolized administration of antiasthmatic drugs is effective and safe, this study examined the effect of aerosolized TXA2 receptor antagonist (S-1452) on allergic bronchoconstriction in passively sensitized and mechanically ventilated guinea pigs. Under the cover of antihistamine, antigen-induced bronchoconstriction was markedly inhibited by pretreatment with aerosolized S-1452 inhalation in a dose-dependent manner. Although aerosolized S-1452 itself provoked weak bronchoconstriction for its partial agonist effect, bronchial responsiveness to inhaled histamine did not change 10 min after S-1452 inhalation. These results indicate that aerosolized S-1452 may be useful in treating bronchial asthma.

Topics: Aerosols; Animals; Asthma; Bridged Bicyclo Compounds; Bronchoconstriction; Dose-Response Relationship, Drug; Fatty Acids, Monounsaturated; Guinea Pigs; Histamine; Male; Receptors, Thromboxane

1. IgG1-mediated anaphylactic bronchoconstriction was elicited by intravenous administration of antigen to guinea-pig 2 days after passive sensitization with IgG1-rich serum, and this response was not affected by heating the serum (at 56 degrees C, for 4 h). IgE-mediated bronchoconstriction, provoked 14 days after passive sensitization with IgE-rich serum, was completely abolished by the heating of the serum. 2. S-1452 (10 mg kg-1, p.o.), a selective thromboxane (Tx) A2 antagonist, significantly but incompletely suppressed the IgG1-mediated bronchoconstriction, but did not affect the IgE-mediated one, while diphenhydramine (5 mg kg-1, i.v.), a histamine antagonist, almost completely inhibited both IgG1- and IgE-mediated bronchoconstriction. 3. Pretreatment with propranolol (1 mg kg-1, i.v.), a beta-adrenergic blocker, in addition to diphenhydramine, caused a long-lasting bronchoconstriction following antigen challenge in both animal models. This histamine-independent bronchoconstriction was markedly suppressed by S-1452 at a low dose of 0.1 mg kg-1. 4. A significant increase in bronchial responsiveness to i.v. acetylcholine (ACh), compared to the prechallenge value, occurred as early as 3 min and persisted for 24 h after antigen challenge in the IgG1 model, but was not observed in the IgE model. S-1452 (10 mg kg-1, p.o.) inhibited the IgG1-mediated bronchial hyperresponsiveness, as assessed 60 min after antigen challenge. 5. A marked elevation of TxB2 levels was observed in bronchoalveolar lavage fluid (BALF) 3 min after antigen challenge in the IgG1 model, while levels were not changed in the IgE model. In contrast, the plasma TxB2 level assessed 1 min after antigen challenge was increased in both the IgGI and IgE models.6. The results indicate that the inhibition of IgGl- but not IgE-mediated bronchoconstriction by higher doses of S-1452 may result from the suppression of increased bronchial responsiveness to allergic mediators such as histamine, which is probably due to TxA2 generated in the airway lumen rather than in plasma. In both the IgGI and IgE models, plasma TxA2 appeared to contribute directly to the bronchoconstriction, its action being almost completely masked by histamine-mediated bronchoconstriction.

Topics: 6-Ketoprostaglandin F1 alpha; Adrenergic beta-Antagonists; Animals; Antibodies, Monoclonal; Antigens; Asthma; Bridged Bicyclo Compounds; Bronchial Hyperreactivity; Bronchoconstriction; Diphenhydramine; Fatty Acids, Monounsaturated; Guinea Pigs; Immunoglobulin E; Immunoglobulin G; Male; Receptors, Prostaglandin; Thromboxane A2; Thromboxane B2

Long-lasting bronchial hyperresponsiveness to i.v. acetylcholine was observed in actively sensitized guinea-pigs after aerosol ovalbumin exposure. The response became significant at 7 h post-challenge and persisted for at least 120 h compared to the response of unsensitized animals. Pretreatment of animals with the specific thromboxane A2 receptor antagonist, S-1452 (calcium (1R,2S,3S,4S)-(5Z)-7-(((phenylsulfonyl)amino)bicyclo[2.2.1] hept-2-yl)hept-5-enoate dihydrate), almost completely inhibited the onset of bronchial hyperresponsiveness, as assessed at 24 and 120 h post-challenge. However, it was ineffective when administered at 1 h post-challenge or 2 h before assessment of bronchial responsiveness. Lung vascular injury occurred transiently immediately after antigen challenge, the kinetics of injury being associated with those for the production of thromboxane B2 in bronchoalveolar lavage fluid. The vascular injury was dramatically suppressed by pretreatment with S-1452. These findings suggest that acutely generated thromboxane A2 plays an important role in the pathogenesis of antigen-induced long-lasting bronchial hyperresponsiveness, probably by producing vascular damage in the lungs.

Topics: Acetylcholine; Administration, Inhalation; Aerosols; Animals; Asthma; Bridged Bicyclo Compounds; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Endothelium, Vascular; Fatty Acids, Monounsaturated; Guinea Pigs; Immunization; Injections, Intravenous; Lung; Male; Ovalbumin; Prostaglandins; Pulmonary Artery; Receptors, Prostaglandin; Thromboxane A2

Although it is well recognized that beta-blockers can induce bronchoconstriction only in patients with asthma, mechanisms of the bronchoconstriction are not well known. We hypothesize that bronchoconstriction induced by beta-blockers may result from inflammatory mediators released by allergic reactions. In this study, we developed a guinea pig model for propranolol-induced bronchoconstriction (PIB) after antigen inhalation and investigated the effect of specific thromboxane (TXA2) receptor antagonists, S-1452 and ONO NT-126, on PIB in passively sensitized and artificially ventilated guinea pigs to determine whether TXA2 is involved in PIB. Propranolol caused bronchoconstriction with 10 mg/ml of propranolol was inhaled 20 min after antigen challenge. On the other hand, propranolol did not produce bronchoconstriction after antigen provocation in nonsensitized guinea pigs or after saline provocation in sensitized animals. Pretreatment of the animals with S-1452 in doses of 0.01 and 0.1 mg/kg and ONO NT-126 in doses of 1.0 and 10 micrograms/kg injected intravenously 15 min after antigen challenge as well as before antigen challenge reduced PIB in a dose-dependent manner. Bronchoconstriction caused by methacholine did not induce PIB. These results suggest that TXA2 has an important role in the pathophysiology of the PIB that develops after the allergic bronchoconstriction.

Topics: Administration, Inhalation; Analysis of Variance; Animals; Asthma; Bridged Bicyclo Compounds; Bronchial Provocation Tests; Constriction, Pathologic; Disease Models, Animal; Dose-Response Relationship, Drug; Fatty Acids, Monounsaturated; Guinea Pigs; Hypersensitivity; Inflammation; Injections, Intravenous; Male; Methacholine Chloride; Premedication; Propranolol; Receptors, Prostaglandin; Thromboxane A2; Time Factors

We examined the effect of a potent thromboxane (Tx) A2 receptor antagonist, calcium (1R, 2S, 3S, 4S)-(5Z)-7-(((phenylsulfonyl)amino)bicyclo[2.2.1] hept-2-yl)-5-heptenoate dihydrate (S-1452), on antigen- and various allergic-spasmogen-induced contractions of guinea pig lung parenchymal strips and on the increase in insufflation pressure, an index of bronchoconstriction, in anesthetized guinea pigs. In isolated guinea pig lung parenchymal strips, S-1452 showed competitive antagonism of the contractile activity of U-46619, a TxA2 mimetic, with a pA2 value of 8.9. The compound also inhibited the contraction induced by prostaglandin (PG) D2 and PGF2 alpha, but a TxA2 synthetase inhibitor, OKY-046, did not. In contrast, both drugs inhibited not only leukotriene (LT) D4-induced contraction but also antigen-induced contraction in the presence of a histamine antagonist. In anesthetized guinea pigs, oral administration of S-1452 markedly inhibited the bronchoconstrictions induced by intravenous injection of U-46619, PGD2, PGF2 alpha, LTD4 and platelet-activating factor (PAF) with ED50 values of 0.006, 0.031, 0.112, 0.033 and 0.115 mg/kg, respectively, but OKY-046 inhibited only that by LTD4 and PAF. Additionally, bronchoconstriction following intravenous injection of antigen was almost completely suppressed by S-1452 (0.1 mg/kg) and partially by OKY-046 (300 mg/kg) in passively sensitized guinea pigs which were treated with diphenydramine and propranolol. The inhibitory effect of S-1452 against U-46619-induced broncho-constriction persisted up to 7 h after oral administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Asthma; Bridged Bicyclo Compounds; Bronchoconstriction; Fatty Acids, Monounsaturated; Guinea Pigs; In Vitro Techniques; Lung; Male; Methacrylates; Muscle Contraction; Prostaglandin Endoperoxides, Synthetic; Receptors, Thromboxane; Thromboxane A2

Effects of a thromboxane A2 receptor antagonist (S-1452) on bronchoconstriction induced by inhaled leukotriene C4 and a leukotriene receptor antagonist (AS-35) on bronchoconstriction caused by inhalation of a thromboxane A2 mimetic (STA2) were studied in anesthetized, artificially ventilated guinea pigs in order to examine the interaction of thromboxane A2 and leukotrienes in airways. 0.01-1.0 mu g/ml of leukotriene C4 and 0.1-1.0 mu g/ml of STA 2 inhaled from ultrasonic nebulizer developed for small animals caused dose-dependent increase of pressure at the airway opening (Pao) which is considered to be an index representing bronchial response. Pretreatment of the animals with inhaled S-1452 (0.01, 0.033 mg/ml) significantly reduced the airway responses produced by 0.01,0.033,0.1,0.33 and 1.0 mu g/ml of leukotriene C4 in a dose dependent manner. While pretreatment with inhaled AS-35 (1mg) did not affect the STA2 dose-response curve. These findings suggest that leukotriene C4 activates thromboxane A2 generation while thromboxane A2 does not influence 5-lipoxygenase pathway in the airways.

Topics: Administration, Inhalation; Animals; Asthma; Bridged Bicyclo Compounds; Bronchoconstriction; Dose-Response Relationship, Drug; Fatty Acids, Monounsaturated; Guinea Pigs; Histamine; Male; Pyridines; Pyrimidines; Pyrimidinones; Receptors, Immunologic; Receptors, Leukotriene; Receptors, Prostaglandin; Receptors, Thromboxane; SRS-A; Tetrazoles; Thromboxane A2