Characterization of high density lipoproteins from patients with severe hypertriglyceridemia

Abstract High density lipoproteins (HDL) were isolated by zonal ultracentrifugation from 6 subjects with severe hypertriglyceridemia. Four subjects had familial endogenous hypertriglyceridemia with fasting chylomicronemia; 2 subjects were non-insulin-dependent diabetics. Plasma triglycerides ranged from 920 to 5440 mg/dl and HDL-cholesterol from 12 to 23 mg/dl. The major HDL from these hypertriglyceridemic subjects had a peak mean density of 1.153 g/ml as compared to 1.140 g/ml for HDL3 from normal subjects. None of the subjects had significant amounts of HDL corresponding to normal HDL 2 . The major subpopulation of hypertriglyceridemic HDL had a mean diameter of 8.4 ± 0.1 nm (range 7.6–9.0 nm). The HDL were enriched in triacylglycerols and depleted in cholesteryl esters and the C apoproteins as compared to control HDL3. The mass ratio of triacylglycerols to cholesteryl esters ranged from 4.00 to 5.22 for the patients versus 0.41 for normal HDL3. The increased content of triacylglycerols partially explains the decreased amount of cholesterol associated with these hypertriglyceridemic HDL.