Effects of simvastatin on the number and composition of apoproteinB-containing lipoproteins in hypercholesterolemia: analysis of apoproteinB in each lipoprotein fraction by highly sensitive latex method.

Abstract

We investigated the effects of simvastatin on the number and composition of apoproteinB (apoB)-containing lipoproteins in thirteen patients with hypercholesterolemia type IIa or IIb by measuring apoB by a highly sensitive latex method. Patients received simvastatin 5-10 mg (7.7 +/- 0.7 mg, mean +/- SEM) daily for 83-218 days (131 +/- 13 days). In both types of patients, treatment with simvastatin significantly reduced plasma cholesterol levels (mean +/- SEM mg/dl: in type IIa from 234.4 +/- 5.4 to 171.4 +/- 7.8, in type IIb from 242.4 +/- 11.6 to 178.8 +/- 9.6), low density lipoprotein (LDL) cholesterol levels (from 122.6 +/- 5.2 to 68.5 +/- 4.6, and from 115.6 +/- 14.0 to 70.4 +/- 11.6 in the two types, respectively) and LDL apoB levels (from 94.5 +/- 6.6 to 60.6 +/- 7.0, and from 85.0 +/- 8.4 to 56.6 +/- 6.2, respectively). There was no significant change in cholesterol, triglyceride (TG) or apoB in very low density lipoprotein (VLDL). High density lipoprotein (HDL) cholesterol did not change in this study. With respect to lipoprotein composition, the ratio of either cholesterol or TG to apoB in VLDL, intermediate density lipoprotein (IDL) and LDL did not change significantly, but that of TG to apoB in the IDL fraction increased in type IIa. Simvastatin promotes more effective reduction in cholesterol and apoB in LDL than in VLDL, probably by increasing the hepatic LDL receptor which preferentially binds LDL.