Accelerated turnover of very low density lipoprotein triglycerides in chronic alcohol users: A possible mechanism for the up-regulation of high density lipoprotein by ethanol

Abstract

The concentration of high density lipoproteins (HDL) is related to the catabolism of triglyceride-rich lipoproteins. In order to elucidate the mechanisms by which alcohol increases plasma HDL levels we measured the turnover kinetics of very low density lipoprotein (VLDL) triglycerides in 10 alcoholic men without liver disease and in nonalcoholic control men matched for age, weight and plasma VLDL triglyceride level. The study was repeated in the alcoholics after a 2-week abstinence period. The alcoholic men had elevated HDL cholesterol but reduced low density lipoprotein (LDL) cholesterol as compared to the controls. The fractional catabolic rate and the total turnover (production) rate of VLDL triglycerides were both significantly increased ( P < 0.05) in the alcoholic men before abstinence. After withdrawal of alcohol both the synthetic rate and the catabolic rate of VLDL triglycerides returned to normal and the HDL (11131-2 and HDL 3) cholesterol fell. The percent decrease in HDL 2 cholesterol during abstinence was positively correlated to the respective fall of VLDL triglyceride fractional catabolic rate ( r= +0.51). The results suggest that the absence of hypertriglyceridemia and the elevated levels of HDL in regular alcohol users may be partly based on increased metabolic clearance of VLDL particles and on subsequent accelerated transfer of the VLDL surface components to HDL.