Background: Lipoprotein lipase (LPL) might play a major role in lipid metabolism by hydrolyzing triglyceride-rich lipoproteins. Decreased LPL activity can trigger early inflammatory responses central to atherosclerosis. However, whether repeated apnea-related hypoxemia influences lipid metabolism in patients with obstructive sleep apnea syndrome (OSAS) remain undefined. This investigation determined whether circulating LPL was influenced by repeated apnea-related hypoxemia, and the effect of nasal continuous positive airway pressure (CPAP) therapy on LPL concentrations in OSAS patients.
Methods and results: The participants of the study were 155 men with OSAS and 39 men without OSAS. Circulating LPL concentrations decreased with the severity of OSAS. They correlated negatively with serum triglyceride, and the linear regression lines between LPL concentrations and triglyceride in OSAS patients were shifted downward compared with those in non-OSAS patients, suggesting that any pathophysiological factor might decrease LPL activity in OSAS patients. Some OSAS patients were subjected to CPAP therapy for 3 months. CPAP therapy increased LPL concentrations and decreased C-reactive protein (CRP) concentrations.
Conclusions: The present study suggests that repeated apnea-related hypoxemia might affect lipid metabolism and augment inflammatory responses, and CPAP therapy could be effective to decrease inflammatory responses and ameliorate lipid metabolism in patients with OSAS.