ozagrel and Bronchitis

Cyclooxygenase products are released by chronic airway inflammation. Our working hypothesis for the present study was that prostanoids augment airway cough sensitivity. The effects of a cyclooxygenase inhibitor, indomethacin (100 mg.day-1 for 4 days), and a thromboxane synthesis inhibitor, OKY-046 (400 mg.day-1 for 4 days), on cough response to inhaled capsaicin were examined in eight patients with asthma, 10 patients with chronic bronchitis, and 10 normal subjects. Capsaicin cough threshold, the lowest concentration of capsaicin eliciting five or more coughs, was measured as an index of airway cough sensitivity. In asthmatics, the cough thresholds with indomethacin treatment (15.7 (GSEM 1.38) microM) and OKY-046 (10.2 (GSEM 1.20) microM) were significantly greater than the value with placebo (6.05 (GSEM 1.25) microM). In patients with chronic bronchitis, the cough threshold was significantly greater with indomethacin (5.94 (GSEM 1.50) microM) than with placebo (3.41 (GSEM 1.33) microM and OKY-046 2.97 (GSEM 1.43) microM). In normal subjects, the capsaicin cough threshold was not altered by indomethacin or OKY-046 treatment. These results support our hypothesis and suggest that thromboxane A2 may be one of the cyclooxygenase products augmenting airway cough sensitivity in asthma, but not in chronic bronchitis.

Topics: Adult; Aged; Asthma; Bronchial Provocation Tests; Bronchitis; Capsaicin; Chronic Disease; Cough; Cross-Over Studies; Cyclooxygenase Inhibitors; Double-Blind Method; Female; Humans; Indomethacin; Male; Methacrylates; Middle Aged; Respiratory Function Tests; Thromboxane-A Synthase; Treatment Outcome

The mechanisms of excessive sputum production are only partially understood. We speculated that a selective thromboxane (Tx) A2 synthetase inhibitor, OKY-046, now used in the treatment of asthma in Japan, could decrease excess sputum production in patients with chronic airways disease. To test this hypothesis, we carried out a double-blind, placebo-controlled study of the effects of OKY-046, administered orally at 400 mg.day-1, on the sputum of patients with chronic bronchitis and patients with diffuse panbronchiolitis. Patients treated with OKY-046 showed a significant decrease (22%) in sputum volume after 1 month, and a 39% decrease after 3 months. Although the rheological properties of the sputum and the concentrations of fucose and immunoglobulin (Ig) A in the sputum remained unchanged, significant decreases were observed in the concentrations of total protein, albumin, sialic acid and phospholipid. Since albumin and fucose are chemical markers of plasma exudation and mucus secretion, respectively, whilst sialic acid and phospholipid are derived both from serum and mucus, our results indicate that this TxA2 synthetase inhibitor reduced sputum volume by inhibiting microvascular leakage in the airway. OKY-046 may, therefore, be of value in the treatment of chronic bronchitis and diffuse panbronchiolitis.

Topics: Adult; Aged; Bronchiolitis; Bronchitis; Chronic Disease; Double-Blind Method; Enzyme Inhibitors; Female; Humans; Male; Methacrylates; Middle Aged; Respiratory Function Tests; Rheology; Sputum; Thromboxane A2; Thromboxane-A Synthase

To determine whether the involvement of thromboxane A2 in bronchial hyperresponsiveness is specific to asthma, we examined the effects of a selective thromboxane synthetase inhibitor (OKY-046) and a cyclooxygenase inhibitor (indomethacin) on bronchial responsiveness to methacholine in patients with bronchial asthma and chronic bronchitis. The provocative concentration of methacholine producing a 20% fall in forced expiratory volume in one second (PC20-FEV1) was measured before and after oral administration of OKY-046 and indomethacin in eight asthmatic and 10 bronchitic subjects. Baseline FEV1 value was not altered by OKY-046 or indomethacin. The geometric mean value of PC20-FEV1 increased significantly (p less than 0.005) from 1.78 to 4.27 mg/ml after OKY-046 in asthmatic subjects, but not in bronchitic subjects. On the other hand, PC20-FEV1 was not altered by indomethacin in all subjects. It was concluded that the involvement of thromboxane A2 in bronchial hyperresponsiveness may be specific to asthma.

Topics: Asthma; Bronchi; Bronchial Provocation Tests; Bronchitis; Chronic Disease; Female; Humans; Male; Methacholine Chloride; Methacholine Compounds; Methacrylates; Middle Aged; Thromboxane A2; Thromboxane-A Synthase

To determine whether the involvement of thromboxane A2 in bronchial hyperresponsiveness (BHR) is specific to asthma, we examined the effects of a selective inhibitor of thromboxane synthetase (OKY-046) and a cyclooxygenase inhibitor (indomethacin) on bronchial responsiveness to methacholine in normal subjects and patients with chronic bronchitis, diffuse bronchiectasis, and intrinsic bronchial asthma. The provocative concentration of methacholine producing a 20 percent fall in forced expiratory volume in 1 s (PC20-FEV1) was measured before and after oral administration of OKY-046 (2,600 mg over four days) and indomethacin (450 mg over three days) in ten normal, ten bronchitic, nine bronchiectatic, and eight asthmatic subjects, respectively. Baseline values of FEV1 and forced vital capacity (FVC) were not altered by OKY-046 or indomethacin. The geometric mean value of PC20-FEV1 increased significantly (p less than 0.005) from 1.78 to 4.27 mg/ml after OKY-046 in asthmatic subjects, but not in normal, bronchitic, or bronchiectatic subjects. On the other hand, PC20-FEV1 increased significantly (p less than 0.005) from 2.19 to 8.13 mg/ml after indomethacin in bronchiectatic subjects, but not in normal, bronchitic, or asthmatic subjects. We conclude that the involvement of thromboxane A2 in BHR may be specific to asthma, and bronchial responsiveness of bronchiectasis may be potentiated by inflammatory release of bronchoconstrictor prostaglandins except for thromboxane A2. Further studies using thromboxane A2 receptor antagonists are needed to confirm the conclusion.

Topics: Acrylates; Asthma; Bronchi; Bronchial Provocation Tests; Bronchiectasis; Bronchitis; Female; Forced Expiratory Volume; Humans; Indomethacin; Male; Methacholine Chloride; Methacholine Compounds; Methacrylates; Middle Aged; Thromboxane A2; Thromboxane-A Synthase; Vital Capacity