Figure 1.

Effects of chronic intermittent hypoxia (CIH) on lipoprotein clearance. CIH inhibits triglyceride-rich lipoprotein clearance (chylomicrons [CM] and very-low-density lipoprotein [VLDL]) by activating angiopoietin-like protein-4 (Angptl-4), a potent inhibitor of lipoprotein lipase (LpL) in the adipose tissue. The decrease in the LpL activity, an enzyme that is anchored at the capillary endothelium, promotes a significant decrease in the hydrolysis of triglycerides into free fatty acids from CM and VLDL particles. The consequence of the LpL inhibition is the prolonged circulation of CM and VLDL in the bloodstream that may favor the progression of atherosclerosis.