ABSTRACT
Objective:To investigate the effect of elevated low-density lipoprotein(LDL)cholesterol on the release of endothelial microvesicles into the circulatory system in elderly patients with obstructive sleep apnea(OSA).Methods:This was a case-control study.A total of 69 elderly inpatients aged ≥ 60 years were divided into the OSA group(n=48)and the normal control group(n=21)based on the apnea/hypopnea index(AHI). Sleep monitoring was carried out in the two groups, and venous blood samples were taken after the monitoring.Density gradient centrifugation was used to extract microparticles and flow cytometry was used to analyze patients' blood levels of endothelial microvesicles.Blood lipid levels of patients were measured by biochemical analysis methods.The correlation between LDL cholesterol levels and endothelial microvesicles in OSA patients was analyzed.Results:LDL cholesterol levels were higher in OSA patients than in normal controls(2.6±0.6 mmol/L vs.2.2±0.7 mmol/L, t=2.089, P=0.041). Endothelial microvesicle levels were elevated in OSA patients compared with the normal controls[(28.2±12.2)×10 -6events/L vs.(19.6±7.8)×10 -6 events/L, t=-3.164, P=0.003]. Endothelial microvesicle levels increased in OSA patients with elevated LDL cholesterol compared with OSA patients with normal LDL cholesterol[(39.3±12.6)×10 -6 events/L vs.(28.2±12.2)×10 -6 events/L, t=2.899, P=0.006]. There was a significant correlation between LDL cholesterol levels and endothelial microvesicle levels in OSA patients( r=0.497, P=0.032), while levels of HDL, total cholesterol, triglycerides, blood pressure and blood glucose had no significant correlation with endothelial microvesicle levels. Conclusions:The level of endothelial microvesicles released into the circulation is higher in elderly OSA patients than in normal elderly people, and the elevated concentration of LDL can further promote the release of endothelial microvesicles in OSA patients.