ozagrel and Bronchial-Hyperreactivity

Thromboxane A2 (TxA2) plays an important role in asthma. TxA2 are newly generated after cellular activation and are produced by not only platelets but also eosinophils, basophils, alveolar macrophages, and neutrophils. Pharmacological actions of TxA2 include potent bronchoconstriction, increased microvascular leakage, impairment of mucociliary clearance, and induction of airway hyperresponsiveness. Recent study demonstrated that TxA2 receptor antagonist decreased the number of eosinophils in bronchial biopsy specimens, suggesting that this type of agent possesses anti-inflammatory actions in asthma. Furthermore, addition of TxA2 synthase inhibitor significantly increased the PEF values in the persistent asthmatic patients despite the treatment with moderate-dose of inhaled corticosteroids. Therefore, these results suggest that TxA2 synthase inhibitor and receptor antagonist are useful for the treatment with symptomatic patients who had already been treated with inhaled corticosteroids.

Topics: Asthma; Benzoquinones; Bronchi; Bronchial Hyperreactivity; Eosinophils; Heptanoic Acids; Humans; Methacrylates; Practice Guidelines as Topic; Receptors, Thromboxane; Thromboxane A2; Thromboxane-A Synthase

Thromboxane A2(TXA2), a platelet aggregator and vasoconstricter, has been implicated as a potential mediator of bronchial asthma. TXA2 induces potent contraction of airway smooth muscles and airway hyperresponsiveness. OKY-046 (ozagrel hydrochloride) is a specific inhibitor of TXA2 synthetase and a new antiasthmatic agent. In a phase III study ozagrel has shown significantly higher effect in ameliorating the asthma symptoms and reduced the dose of concomitant steroid therapy compared to azelastine hydrochloride. Both basical and clinical studies showed that TXA2 synthetase inhibitor is effective on airway hyperresponsiveness. In this review the role of TXA2 synthetase inhibitor in current asthma therapy, which is based on the Japanese guideline of allergic disorders, was discussed.

Topics: Asthma; Bronchial Hyperreactivity; Clinical Trials as Topic; Humans; Methacrylates; Thromboxane A2; Thromboxane-A Synthase

We investigated the effect of thromboxane (TX) synthetase inhibitor, OKY-046, on bronchial hypersensitivity in 16 asthmatics by a double-blind, placebo-controlled, crossover trial. Bronchial sensitivity to methacholine was measured by Astograph. Blood samples were taken to measure plasma levels of TX metabolites. No significant differences of forced expiratory volume in 1 sec (FEV1), bronchial sensitivity, or bronchial reactivity were observed after OKY-046 administration, compared to baseline or after placebo. However, responders showed a significant decrease in the plasma TXB2/6-keto-PGF1alpha ratio as compared to nonresponders. Our data failed to confirm an inhibitory effect of OKY-046 on bronchial hypersensitivity, but suggested the importance of its therapeutic dose monitoring.

Topics: 6-Ketoprostaglandin F1 alpha; Adolescent; Adult; Asthma; Bronchial Hyperreactivity; Double-Blind Method; Enzyme Inhibitors; Female; Forced Expiratory Volume; Humans; Male; Methacrylates; Placebos; Spirometry; Thromboxane B2; Thromboxane-A Synthase

ONO-1301 is a novel drug that acts as a prostacyclin agonist with thromboxane A(2) (TxA(2)) synthase inhibitory activity. We investigated the effect of ONO-1301 on development of airway allergic inflammation.. Mice sensitized and challenged to ovalbumin (OVA) received ONO-1301, OKY-046 (TxA(2) synthase inhibitor), beraprost, a prostacyclin receptor (IP) agonist, ONO-1301 plus CAY10449 (selective IP antagonist) or vehicle during the challenge period. Twenty-four hours after the OVA challenge, airway hyperresponsiveness (AHR) to methacholine was assessed and bronchoalveolar lavage was performed. Lung specimens were excised for goblet cell staining and analysis of lung dendritic cells (DCs). Bone marrow-derived dendritic cells (BMDCs) were generated, in the presence or absence of drugs, for analysis of DC function.. Mice that received ONO-1301 showed significantly lower AHR, airway eosinophilia, T-helper type 2 cytokine levels, mucus production and lung DCs numbers than vehicle-treated mice. These effects of ONO-1301 were mostly reversed by CAY10449. BMDCs treated with ONO-1301 alone showed lower DC functions, such as expression of costimulatory factors or stimulation to spleen T cells.. These data suggest that ONO-1301 may suppress AHR and airway allergic inflammation through modulation of DCs, mainly mediated through the IP receptor. This agent may be effective as an anti-inflammatory drug in the treatment of asthma.

Topics: Animals; Bronchial Hyperreactivity; Dendritic Cells; Disease Models, Animal; Epoprostenol; Female; Inflammation; Methacrylates; Mice; Mice, Inbred BALB C; Ovalbumin; Pyridines; Thromboxane-A Synthase; Thromboxanes

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

Effects of Y-24180 on antigen-induced asthmatic responses were evaluated in actively sensitized guinea pigs and the effects were compared with those of several anti-asthmatic drugs.. Male Hartley guinea pigs were used.. Guinea pigs were actively sensitized with ovalbumin and were pretreated with pyrilamine Y-24180 was orally administered to the animals 3 h and others were 1 h before the antigen challenge.. The airway hyperresponsiveness was measured according to the method of Konzett and Rössler with some modifications. The immediate asthmatic response (IAR) and late asthmatic response (LAR) were measured by the oscillation method. Inflammatory cells infiltrated into the lungs were counted after the bronchoalveolar lavage.. Under oral administration before or after the challenge with antigen, Y-24180, OKY-046, and ONO-1078 suppressed the antigen-induced airway hyperresponsiveness. Moreover, Y-24180, ONO-1078, AA-2414, and theophylline suppressed both the IAR and LAR, but OKY-046 only suppressed the LAR. Among the test drugs, only Y-24180 and theophylline suppressed the antigen-induced accumulation of eosinophils in the bronchoalveolar lavage fluid.. The data indicate practical participation of PAF in the development of antigen-induced asthmatic responses in animals, and usefulness of Y-24180 in the clinical treatment of asthma as well as other anti-asthmatic drugs.

Topics: Administration, Oral; Aerosols; Animals; Anti-Allergic Agents; Anti-Asthmatic Agents; Asthma; Azepines; Benzoquinones; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Bronchodilator Agents; Chromones; Enzyme Inhibitors; Guinea Pigs; Heptanoic Acids; Histamine Antagonists; Leukotriene Antagonists; Male; Methacrylates; Ovalbumin; Platelet Membrane Glycoproteins; Pyrilamine; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Serine Proteinase Inhibitors; Signal Transduction; Theophylline; Thromboxane-A Synthase; Triazoles

Platelet-activating factor (PAF) is a potent proinflammatory compound potentially involved in the pathogenesis of inflammatory disorders, including bronchial asthma. To elucidate the pathophysiologic roles of PAF in bronchial asthma, we studied airway responsiveness in transgenic mice overexpressing PAF receptor. In the transgenic mice, PAF-induced airway smooth muscle contraction was demonstrated by physiologic and morphometric analyses, whereas there was no significant response in the littermate control group. The PAF-elicited bronchoconstriction in the transgenic mice was significantly reduced not only by a PAF receptor antagonist (WEB-2086) but also by a thromboxane synthesis inhibitor (indomethacin or ozagrel), an inhibitor of 5-lipoxygenase-activating protein (MK-886), or a cysteinyl leukotriene (LT) antagonist (pranlukast). LTB4 receptor antagonist (ONO-4057), however, had no effect on the PAF-induced responses. The transgenic mice showed a bronchial hyperreactivity to methacholine challenge, which was also inhibited by pretreatment with either thromboxane synthesis inhibitor or cysteinyl LT antagonist. These observations suggest that both thromboxane A2 and cysteinyl LTs (LTC4, LTD4, and LTE4) are involved in the bronchial responses to PAF or cholinergic stimulus in mice. The transgenic mice overexpressing PAF receptor may provide an appropriate model to study various PAF-related lung diseases, including bronchial asthma.

Topics: Animals; Azepines; Bronchi; Bronchial Hyperreactivity; Chromones; Indoles; Indomethacin; Leukotriene Antagonists; Leukotrienes; Lipoxygenase Inhibitors; Lung; Methacrylates; Mice; Mice, Transgenic; Phenylpropionates; Platelet Activating Factor; Platelet Membrane Glycoproteins; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Receptors, Leukotriene B4; Thromboxanes; Triazoles

We studied the effects of the thromboxane-synthetase inhibitor ozagrel in 22 patients with chronic persistent coughing who did not have airwayhyperresponsiveness. Treatment with ozagrel (400 mg/day for 2 weeks) reduced coughing in 12 patients. Sputum from the patients in whom ozagrel was effective had a higher percentage of lymphocytes and a lower percentage of neutrophils than did sputum from those in whom ozagrel was not effective. Furthermore, in the former group the capsaicin cough threshold increased but in the latter it did not change consistently. These data indicate that thromboxane A2 may contribute to coughing associated with lymphocytic airway inflammation.

Topics: Adult; Aged; Bronchial Hyperreactivity; Chronic Disease; Cough; Enzyme Inhibitors; Female; Humans; Male; Methacrylates; Middle Aged; Thromboxane A2; Thromboxane-A Synthase

The therapeutic effect of a thromboxane A2 (TXA2) synthetase inhibitor on asthma is still controversial. This study was aimed at clarifying its effect on asthmatic reactions in guinea pigs. Both ovalbumin (OVA)- and platelet activating factor (PAF)-induced dual phase airway spasm and hyperreactivity in guinea pigs were used as the asthma model. Our results demonstrated that aerosol administration of OKY-046 could inhibit both OVA- and PAF-induced late phase bronchoconstriction and airway hyperreactivity to methacholine in OVA sensitized guinea pigs. PAF administration could also induced dual phase bronchoconstriction in normal guinea pigs. Similarly, late phase airway spasm and airway hyperreactivity after PAF exposure was also blocked by OKY-046. In conclusion, aerosol administration of OKY-046 is a safe and effective way to modulate OVA- and PAF-induced asthmatic reactions. The protective effect of OKY-046 on OVA- and PAF-induced late phase bronchoconstriction and airway hyperreactivity indicates that TXA2 might play an important role in the late phase asthmatic reaction and airway hyperreactivity. The normalization of PAF-induced airway hyperreactivity by OKY-046 also indicates that PAF induced airway inflammation might be through the generation of TXA2.

Topics: Animals; Asthma; Bronchial Hyperreactivity; Dose-Response Relationship, Drug; Guinea Pigs; Histamine Antagonists; Male; Methacrylates; Ovalbumin; Platelet Activating Factor; Thromboxane-A Synthase; Time Factors

The effects of ozagrel, a thromboxane A2 (TXA2) synthase inhibitor, and CV-3988, a platelet activating factor (PAF) antagonist, was investigated on the repeatedly antigenic challenge-induced airway hyperresponsiveness (AHR) in rats. Rats were actively sensitized with DNP-Ascaris antigen and received 3 inhalations of antigen (challenges) or saline (sensitized control) every 48 hr. These animals were also pretreated with ozagrel (100 mg/kg, p.o., 30 min before), CV-3988 (3 mg/kg, i.v., 5 min before) or respective vehicle (water and saline, respectively) before each inhalation of antigen or saline. The in vivo airway responsiveness to cumulatively inhaled acetylcholine (ACh; 0.001-0.03%, each for 3 min) was measured 24 hr after the last inhalation of antigen or saline under anesthesia. A marked AHR was observed after repeated antigenic challenge when compared with the sensitized control group (5.5-9.5 times in order). This AHR was significantly, but partly, attenuated by pretreatment with ozagrel although this treatment alone had no effect on the airway responsiveness to inhaled ACh in sensitized control animals. On the other hand, CV-3988 had no inhibitory effect on this AHR. These findings suggest that TXA2, but not PAF, is one of the most important mediators participating in the pathogenesis of the antigen-induced AHR in rats.

Topics: Acetylcholine; Animals; Antigens, Helminth; Ascaris; Bronchial Hyperreactivity; Dinitrobenzenes; Lung; Male; Methacrylates; Phospholipid Ethers; Platelet Activating Factor; Rats; Rats, Wistar; Respiration; Thromboxane A2; Thromboxane-A Synthase; Vaccination

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

The effects of OKY-046 (thromboxane A2 (TXA2) synthetase inhibitor) and ONO-3708 (TXA2 receptor antagonist) on antigen-induced airway hyperreactivity in guinea pigs were investigated. Ketotifen was used as a reference drug. Seven inhalations of an antigen into actively sensitized animals resulted in an increase in airway reactivity to acetylcholine. Twenty-four hours after the final inhalation, the number of leukocytes (macrophages, neutrophils, eosinophils and lymphocytes) and the quantity of mediators (thromboxane B2, leukotriene D4 and histamine) in bronchoalveolar lavage fluid increased. All examined drugs inhibited the antigen-induced airway hyperreactivity to acetylcholine. Whereas ketotifen inhibited an accumulation of inflammatory cells (eosinophils and neutrophils) in bronchoalveolar lavage fluid, OKY-046 and ONO-3708 had no effect on the accumulation of inflammatory cells. OKY-046, but not ketotifen and ONO-3708, inhibited an increase of thromboxane B2 in the bronchoalveolar lavage fluid after antigen provocation. These results suggest the participation of TXA2 in the onset of antigen-induced airway hyperresponsiveness in guinea pigs, and the efficacy of TXA2 inhibitors, without affecting the accumulation of inflammatory cells in bronchoalveolar lavage fluid.

Topics: Acetylcholine; Administration, Inhalation; Animals; Bronchi; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Guinea Pigs; Ketotifen; Leukocyte Count; Male; Methacrylates; Thromboxane A2; Thromboxane-A Synthase; Trachea

The anti-asthmatic effects of CS-518 (sodium 2-(1-imidazolylmethyl)-4,5-dihydrobenzo[b]thiophene-6-carboxylate) , a specific thromboxane A2 (TXA2) synthase inhibitor, were investigated in the ovalbumin-sensitized guinea pig asthmatic model. Although CS-518 slightly inhibited (about 25%) whole bronchoconstriction, it significantly inhibited the antigen-induced bronchoconstriction mediated by slow-reacting substance of anaphylaxis (SRS-A), which was not reduced by chlorpheniramine, a histamine H1 antagonist. On the other hand, indomethacin, a cyclooxygenase inhibitor, potentiated the SRS-A-mediated constriction. CS-518 strongly, and indomethacin slightly, suppressed the leukotriene D4-induced bronchoconstriction. CS-518 clearly inhibited the antigen-induced airway hyperresponsiveness, but this compound had no effect on the airway hyperresponsiveness induced by U-46619, a TXA2-mimetic agent, and propranolol. These results suggest that CS-518 suppresses the development of bronchoconstriction and airway hyperresponsiveness in asthmatic models by inhibition of TXA2 synthesis with the concomitant increase in bronchodilating prostaglandins such as prostaglandin E2 and prostaglandin I2.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Asthma; Bronchial Hyperreactivity; Bronchoconstriction; Chlorpheniramine; Disease Models, Animal; Guinea Pigs; Indomethacin; Male; Methacrylates; Ovalbumin; Propranolol; Prostaglandin Endoperoxides, Synthetic; SRS-A; Thiophenes; Thromboxane A2; Thromboxane-A Synthase; Vasoconstrictor Agents

In this study, we investigated the effects of peroral (p.o.) administration of a thromboxane A2 (TXA2) synthetase inhibitor, OKY-046, on the airway hyperresponsiveness (AHR) in guinea pigs induced by intravenous administration of leukotriene C4 (LTC4). A 3 micrograms/kg/hr LTC4 infusion induced airway wall thickening (AWT) and AHR to 1.8 and 3.6 micrograms/kg histamine bolus shot. OKY-046 100 mg/kg p.o. partially inhibited the AHR induced by LTC4 without inhibition of AWT. Previously, we have reported that LTC4-induced AHR was partially inhibited, to the same exert as by OKY-046, by TXA2 receptor antagonists, ONO-NT-126 and ONO-8809. These data suggest that intravenous administration of LTC4 generates TXA2, and TXA2 augments LTC4-induced AHR partially in guinea pigs.

Topics: Administration, Oral; Animals; Bronchial Hyperreactivity; Guinea Pigs; Injections, Intravenous; Male; Methacrylates; SRS-A; Thromboxane A2; Thromboxane-A Synthase

We attempted to obtain a new airway hyperresponsiveness model using DNP-Ascaris extract (DNP-Asc)-induced rat allergic asthma. Male Wistar rats were actively sensitized with DNP-Asc, and challenged in a non-anesthetized state by inhalation of the antigen for 10 min in a chamber. One, 6 and 24 hr after DNP-Asc challenge, the responsiveness of the airway smooth muscles to inhaled acetylcholine (ACh) was determined using a modified Konzett-Rössler method under anesthesia. Twenty four hr after the challenge, a significant and marked airway hyperresponsiveness was seen. The increase in airway responsiveness was significantly inhibited by pretreatments with a leukotriene antagonist, ONO-1078, and a thromboxane synthetase inhibitor, ozagrel, and tended to be inhibited by a PAF antagonist, CV-3988. The hyperresponsiveness induced by DNP-Asc challenge was accompanied by airway inflammation determined by dye exudation. From the above results, it is indicated that a model of airway hyperresponsiveness was established in rats with allergic asthma, and that the chemical mediators involved in the response might be leukotrienes, thromboxane A2 and PAF.

Topics: Acetylcholine; Animals; Ascaris; Asthma; Bronchial Hyperreactivity; Capillary Permeability; Chromones; Depression, Chemical; Dinitrophenols; Disease Models, Animal; Male; Methacrylates; Phospholipid Ethers; Platelet Activating Factor; Rats; Rats, Wistar; SRS-A; Thromboxane-A Synthase; Tissue Extracts

In the present study, we investigated (1) whether airway responsiveness to inhaled histamine-aerosol could be induced during 7-d exposure of guinea pigs to 4 ppm NO2 and, if so, (2) whether thromboxane A2 may be involved in such increase. Female Hartley guinea pigs were divided into 6 groups (n = 15/group). Three groups were exposed to filtered air and the other 3 groups were exposed to NO2 for 1, 3, or 7 d (24 h/d). Baseline specific airway resistance (SRaw0) did not change significantly after exposure to 4 ppm NO2 or air. Airway responsiveness was determined 1 wk before the beginning of exposure and on the day of termination of the exposure. Prior to exposure to NO2, the EC200His, the concentrations of inhaled histamine necessary to double SRawNaCl (SRaw after inhalation of 0.9% NaCl), were 1.07 +/- 0.20, 1.30 +/- 0.20, and 1.01 +/- 0.18 mM for the 3 groups later given NO2 for 1, 3, and 7 d, respectively. Following exposure to NO2 for 1, 3, or 7 d, EC200His values were 1.42 +/- 0.25, 0.66 +/- 0.10 (p < .05), and 1.05 +/- 0.22 mM, respectively. These results show that 7-d exposure to 4 ppm NO2 induced a significant increase in airway responsiveness on d 3. Exposure to air had no significant effect on the airway responsiveness. This transient hyperresponsiveness was inhibited by a specific inhibitor of thromboxane synthetase, OKY 046. These results indicated that (1) a lower concentration (4 ppm) of NO2 than that previously reported can induce transient hyperresponsiveness in guinea pigs during appropriate long-term exposure, and (2) thromboxane A2 may play an important role in this transient airway hyperresponsiveness.

Topics: Administration, Inhalation; Air Pollutants; Airway Resistance; Animals; Asthma; Bronchial Hyperreactivity; Drug Hypersensitivity; Female; Guinea Pigs; Histamine; Lung; Methacrylates; Nitrogen Dioxide; Thromboxane A2; Thromboxane-A Synthase; Time Factors

Effects of a thromboxane synthetase inhibitor (OKY-046) and a cyclooxygenase inhibitor (indomethacin) on bronchial hyperresponsiveness induced by subthreshold concentration of aerosolized thromboxane A2 analogue (STA2) were investigated in anesthetized, artificially ventilated guinea pigs in order to examine the role of the cyclooxygenase pathway in bronchial hyperresponsiveness. Pretreatment with aerosolized OKY-046 significantly inhibited the bronchial hyperresponsiveness to histamine, but pretreatment with intravenous indomethacin showed a tendency to potentiate bronchial hyperresponsiveness. These results suggest that subthreshold concentration of thromboxane A2 contributes to bronchial hyperresponsiveness through activating the cyclooxygenase pathway including thromboxane A2 synthesis, and that the released cyclooxygenase products have an inhibitory effect on the bronchial hyperresponsiveness in guinea pigs.

Topics: Aerosols; Animals; Asthma; Bronchial Hyperreactivity; Bronchoconstriction; Dose-Response Relationship, Drug; Guinea Pigs; Indomethacin; Male; Methacrylates; Thromboxane A2