Decreased sL-selectin serum levels in sleep apnea syndrome patients with cardiovascular diseases

Background. Obstructive sleep apnea syndrome (OSA) is a common disorder associated with an increased risk of cardiovascular diseases. Objectives. sL-selectin is an adhesion molecule released from the surface of leukocytes as they are activated and may inhibit leukocyte attachment to the endothelium. The aim of this study was to evaluate sL-selectin serum levels in OSA patients with cardiovascular diseases. Material and methods. A total of 163 OSA patients were enrolled in the study. The mean age was 55.41 +/- 8.63 years and the mean AHI (apnea hypopnea index) was 35.02 +/- 22.28/h. A control group was composed of 59 healthy subjects. All subjects underwent a nocturnal respiratory polygraphy. sL-selectin serum levels were measured using the enzyme-linked immunosorbent assay (ELISA) method. Results. sL-selectin serum levels were significantly lower in OSA patients than in the control group (1080.02 +/- 175.29 vs 1350.73 +/- 569.75 ng/mL, p < 0.05). In addition, there was a negative correlation between sL-selectin levels and AHI and DI and a positive correlation between sL-selectin levels and mean and minimum saturation. sL-selectin levels were lower in OSA patients with cardiovascular diseases than in those without co-morbidities. We also found that sL-selectin correlated positively with HDL-cholesterol (high density lipoprotein) and negatively with uric acid and CRP (C-reactive protein). Conclusions. Our work, together with observations relating to other diseases and experimental studies, suggests that lower sL-selectin levels could play a role in an increased risk of cardiovascular complications in sleep apnea syndrome. However future studies are needed to understand the role of sL-selectin in sleep apnea syndrome.