[Platelet activation in obstructive sleep apnea syndrome]

The incidences of cardiovascular and cerebrovascular diseases are reportedly higher in patients with obstructive sleep apnea (OSA) than in OSA-free subjects, though the mechanism remains unknown. Recently, the contribution of activated platelets to a number of pathological conditions such as stroke or ischemic heart disease has been suggested. We hypothesized that the expression of activated platelet markers resulting from OSA might be higher than in healthy subjects. By flow cytometry using monoclonal antibodies, we measured two such markers, PAC-1 and CD 62 P, in OSA patients and healthy subjects. Twelve healthy men (age, 52.7 +/- 12.8 y/o; and body mass index (BMI), 22.2 +/- 16.1 kg/m2; mean +/- S.D.) and 20 male patients with OSA (age, 50 +/- 7.96 y/o; BMI, 28.1 +/- 3.3 kg/m2; apnea hypopnea index (AHI), 38.2 +/- 21.2 times/hr; and lowest SpO2, 75.6 +/- 11.3%) were enrolled in this study. PAC-1 expression was significantly higher in OSA patients (65.1 +/- 17.8%) than in healthy subjects (16.8 +/- 7.4%), as was CD 62 P expression (8.5 +/- 8.8% vs. 0.88 +/- 0.57%). The increase in PAC-1 expression was correlated with AHI and the arousal index. These findings suggest that activated platelet markers could be good indicators for untreated OSA.