Effects of simvastatin on plasma lipoprotein subfractions, cholesterol esterification rate, and cholesteryl ester transfer protein in type II hyperlipoproteinemia

Abstract

We investigated the effects of simvastatin on plasma levels of lipoprotein subfractions, cholesterol esterification rates and activities of cholesteryl ester transfer protein in 28 patients with type II hyperlipoproteinemia (i.e., nonfamilial hyperlipoproteinemia type IIa and type IIb, and heterozygous familial hypercholesterolemia (FH)). Plasma levels of VLDL-cholesterol (C) and VLDL-triglyceride (TG) were significantly reduced overall by 12.9 ± 58.0% (mean ± S.D.; P < 0.05) and 4.2 ± 54.2% ( P < 0.05) respectively, but not in FH. Plasma levels of IDL-C and IDLT-G were decreased overall by 23.2 ± 47.5% ( P < 0.001) and 12.3 ± 49.7% ( P < 0.05), respectively, again mainly due to decreases seen in nonfamilial type II hyperlipoproteinemia. Plasma levels of LDL1 (1.019 < d < 1.045)-C and LDL1-TG were significantly reduced by 33.1 ± 12.9% ( P < 0.001) and 23.3 ± 24.7% ( P < 0.001), respectively. Plasma levels of LDL2 (1.045 < d < 1.063)-C were significantly reduced by 22.9 ± 18.1% ( P < 0.001) overall but not in FH. Gradient PAGE showed no consistant changes in the distribution of LDL particles. Thus, plasma levels of all apo B-containing lipoprotein subfractions were reduced by simvastatin, but its effects varied among the three subgroups. Cholesterol esterification rates were suppressed by 9.3 ± 19.7% ( P < 0.01) and activities of cholesteryl ester transfer protein were reduced by 30.6 ± 21.5% ( P < 0.001). Changes in CETP activity and in plasma levels of cholesterol in lipoprotein subfractions were not correlated. Thus, the changes in distribution of lipoprotein subfractions were not due mainly to CETP suppression.