Changes in ultracentrifugally separated plasma lipoprotein subfractions in patients with polygenic hypercholesterolemia, familial combined hyperlipoproteinemia, and familial hypercholesterolemia after treatment with atorvastatin

•Statins reduce plasma low-density lipoprotein (LDL) by stimulating hepatic LDL uptake via LDL receptors.•It is unclear whether statins equally stimulate uptake of all subfractions via LDL receptors.•LDL-receptor activity and the decrease in plasma LDL subfractions were studied.•Atorvastatin treatment reduced plasma levels of the 3 LDL subfractions.•LDL-receptor activity was negatively correlated only with medium-density LDL decreases.

BackgroundPlasma levels of low-density lipoproteins (LDLs) are decreased through stimulation of their hepatic uptake by statins via an LDL receptor. However, it is unclear whether statins equally stimulate the hepatic uptake of all LDL subfractions.ObjectiveWe compared the effects of atorvastatin on 3 LDL subfractions, and their associations with LDL-receptor activities, in Japanese patients with polygenic hypercholesterolemia (PHC), familial combined hyperlipoproteinemia (FCHL), and familial hypercholesterolemia (FH).Materials and methodsAtorvastatin was administered to patients with PHC (n = 11), FCHL (n = 16), and FH (n = 13). We measured plasma levels of lipids, remnant-like particle cholesterol, apoproteins, and cholesterol in lipoprotein fractions. Sequential ultracentrifugation was performed to subfractionate the plasma lipoproteins, and lymphocyte LDL-receptor activities were estimated using flow cytometry.ResultsThe average daily dosage of atorvastatin was 10, 27, and 40 mg in patients with PHC, FCHL, and FH, respectively; after 12 months of atorvastatin treatment, LDL cholesterol (LDL-C) plasma levels decreased by 44%, 50%, and 53%, respectively (all, P < .0001). Atorvastatin reduced low-density LDL-C plasma levels in patients with PHC (48% reduction), FCHL (53%), and FH (46%) (all, P < .0001). Plasma levels of medium-density and high-density LDL-C were also significantly reduced in the 3 patient groups (all, P ≤ .0147). LDL-receptor activity was negatively correlated with baseline levels of medium-density LDL-C and with the decreases in plasma md-LDL-C levels.ConclusionAtorvastatin decreased the levels of the 3 LDL fractions. The md-LDL decrease appeared to be mainly because of stimulation of LDL-receptor activity.