thromboxane-b2 and Dyspnea

It has been reported that the biosynthesis of thromboxane A2 (TXA2) is enhanced in platelets in the presence of chronic obstructive pulmonary disease (COPD), and 11-dehydro-TXB2, a urinary metabolite of thromboxane, also increases in blood. In the present study, seratrodast (CAS 112665-43-7, Bronica), a TXA2 receptor antagonist, was administered to 14 patients with chronic pulmonary emphysema in the stable phase for 8 weeks. Respiratory distress was evaluated in the attending physicians' judgments using the Hugh-Jones (H-J) classification, and also by the patients themselves using the Borg scale. Respiratory function tests, including forced vital capacity (FVC), percent of one second forced expiratory volume (FEV1.0%), arterial blood gases during respiration of room air, and peak expiratory flows (PEF) (morning and evening), and measurement of plasma 11-denhydro-TXB2 and TXB2 levels were performed before and 8 weeks after the start of administration, as well as at the time of the start of administration. The results revealed significant improvement of respiratory distress, evaluated on both the H-J classification and the Borg scale, at week 8. Although no significant changes were observed in plasma TXB2 levels, the plasma 11-dehydro-TXB2 level significantly decreased at week 8. Among the respiratory function parameters examined, only FVC was significantly improved. These results indicated that seratrodast is useful for the improvement of respiratory distress in patients with chronic pulmonary emphysema in the stable phase.

Topics: Aged; Aged, 80 and over; Anti-Asthmatic Agents; Benzoquinones; Carbon Dioxide; Chronic Disease; Dyspnea; Female; Forced Expiratory Volume; Heptanoic Acids; Humans; Immunoglobulin E; Male; Middle Aged; Oxygen; Peak Expiratory Flow Rate; Prostaglandin Antagonists; Pulmonary Emphysema; Respiratory Function Tests; Smoking; Thromboxane A2; Thromboxane B2

We investigated the plasma concentration of thromboxane B2 (TXB2), a stable metabolite of thromboxane A2 (TXA2), to assess platelet activation in 78 patients who had pulmonary hypertension associated with congenital heart disease (PH group) and 16 patients with almost normal hemodynamics (control group).. The PH group was divided into two subgroups: pulmonary vascular resistance (Rp) < or = 10 U/m2 (Rp < or = 10 group) and > 10 U/m2 (Rp > 10 group). In addition, the Rp < or = 10 group was divided on the basis of clinical symptoms into groups with dyspnea (dyspnea[+] group) and without dyspnea (dyspnea[-] group). Plasma TXB2 levels were measured by radioimmunoassay. Plasma TXB2 levels in the three groups (control, Rp < or = 10, and Rp > 10) were significantly different (P < .005); the TXB2 levels in the Rp < or = 10 group were significantly higher than the others. Among the Rp < or = 10 patients, the plasma TXB2 levels were significantly higher in the dyspnea(+) group than in the dyspnea(-) group (P < .0001). In addition, the pulmonary-to-systemic flow ratio and pulmonary blood flow divided by body surface area were significantly higher in the dyspnea(+) group than in the dyspnea(-) group (P < .02 and P < .002, respectively).. These findings suggest that platelet activation led to increased TXA2 release in patients with pulmonary hypertension, especially those with dyspnea and Rp < or = 10. TXA2 release from platelets probably caused constriction of the pulmonary arterioles and the bronchi, thus worsening pulmonary hypertension and dyspnea in these patients. In the patients with high Rp values, it was considered that the number of pulmonary arterioles where platelets could be activated had been reduced.

Topics: Adolescent; Adult; Child; Child, Preschool; Dyspnea; Female; Heart Defects, Congenital; Humans; Hypertension, Pulmonary; Infant; Male; Osmolar Concentration; Platelet Activation; Pulmonary Circulation; Reference Values; Thromboxane B2