DETERMINANTS OF PLASMA HDL-CHOLESTEROL IN HYPERTRIGLYCERIDEMIC PATIENTS - ROLE OF CHOLESTEROL-ESTER TRANSFER PROTEIN AND LECITHIN CHOLESTERYL ACYL TRANSFERASE

Hypertriglyceridemic patients commonly have low levels of HDL choleste rol. Elevated triglycerides per se may be one cause of low HDL levels, but other factors also may be involved. The current study was designe d to define the role of cholesterol-ester transfer protein (CETP) in c ausation of a low HDL cholesterol in hypertriglyceridemic patients; in addition other factors-lecithin cholesterol acyl transferase (LCAT), hepatic triglyceride lipase (HTGL), and lipoprotein lipase (LPL)-were examined. Plasma activities of CETP and LCAT were measured in 137 male patients with moderate hypertriglyceridemia (plasma triglycerides [TG s] 200 to 500 mg/dL and LDL cholesterol <160 mg/dL). Results were comp ared with those from 50 normolipidemic men of similar age and body hab itus. In addition, lipase activities in postheparin plasma were measur ed in 118 of the subjects with hypertriglyceridemia. The activities of CETP and LCAT were 17% (P<.01) and 7% (P<.05), respectively, higher i n the hypertriglyceridemic group than in control subjects. By stepwise regression analysis CETP appeared to contribute 15.2% and LCAT 9.8% t o variation in HDL-cholesterol levels. Activities of LPL and HTGL toge ther contributed an additional 14.1% to HDL-cholesterol variation. In contrast, levels of plasma TG accounted for only 5.4% of the variation . There were no differences in relative contributions of these paramet ers in patients with and those without coronary heart disease. This st udy indicates that several factors contribute to the variation in HDL- cholesterol levels in hypertriglyceridemic patients, and five factors- CETP, LCAT, HTGL, LPL, and triglyceride levels-account for almost half of this variation.