Atorvastatin decreases apolipoprotein C-III in apolipoprotein B-containing lipoprotein and HDL in type 2 diabetes: a potential mechanism to lower plasma triglycerides.

OBJECTIVE: Apolipoprotein (apo)C-III is a constituent of HDL (HDL apoC-III) and of apoB-containing lipoproteins (LpB:C-III). It slows the clearance of triglyceride-rich lipoproteins (TRLs) by inhibition of the activity of the enzyme lipoprotein lipase (LPL) and by interference with lipoprotein binding to cell-surface receptors. Elevated plasma LpB:C-III is an independent risk factor for cardiovascular disease. We studied the effect of atorvastatin on plasma LpB:C-III and HDL apoC-III. RESEARCH DESIGN AND METHODS: We studied the effect of 30 weeks' treatment with 10 and 80 mg atorvastatin on plasma apoC-III levels in a randomized, double-blind, placebo-controlled trial involving 217 patients with type 2 diabetes and fasting plasma triglycerides between 1.5 and 6.0 mmol/l. RESULTS: Baseline levels of total plasma apoC-III, HDL apoC-III, and LpB:C-III were 41.5 +/- 10.0, 17.7 +/- 5.5, and 23.8 +/- 7.7 mg/l, respectively. Plasma apoC-III was strongly correlated with plasma triglycerides (r = 0.74, P < 0.001). Atorvastatin 10- and 80-mg treatment significantly decreased plasma apoC-III (atorvastatin 10 mg, 21%, and 80 mg, 27%), HDL apoC-III (atorvastatin 10 mg, 22%, and 80 mg, 28%) and LpB:C-III (atorvastatin 10 mg, 23%, and 80 mg, 28%; all P < 0.001). The decrease in plasma apoC-III, mainly in LpB:C-III, strongly correlated with a decrease in triglycerides (atorvastatin 10 mg, r = 0.70, and 80 mg, r = 0.78; P < 0.001). Atorvastatin treatment also leads to a reduction in the HDL apoC-III-to-HDL cholesterol and HDL apoC-III-to-apoA-I ratios, indicating a change in the number of apoC-III per HDL particle (atorvastatin 10 mg, -21%, and 80 mg, -31%; P < 0.001). CONCLUSIONS: Atorvastatin treatment resulted in a significant dose-dependent reduction in plasma apoC-III, HDL apoC-III, and LpB:C-III levels in patients with type 2 diabetes. These data indicate a potentially important antiatherogenic effect of statin treatment and may explain (part of) the triglyceride-lowering effect of atorvastatin.

Atorvastatin dose-dependently decreases hepatic lipase activity in type 2 diabetes: effect of sex and the LIPC promoter variant.

OBJECTIVE: Hepatic lipase (HL) is involved in the metabolism of several lipoproteins and may contribute to the atherogenic lipid profile in type 2 diabetes. Little is known about the effect of cholesterol synthesis inhibitors on HL activity in relation to sex and the hepatic lipase gene, the LIPC promoter variant in type 2 diabetes. Therefore, we studied the effect of atorvastatin 10 mg (A10) and 80 mg (A80) on HL activity in 198 patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: Patients (aged 45-75 years, without manifest coronary artery disease, total cholesterol 4.0-8.0 mmol/l, and fasting triglycerides [TG] 1.5-6.0 mmol/l) were included in a double-blind, randomized, placebo-controlled trial for 30 weeks (Diabetes Atorvastatin Lipid Intervention study). RESULTS: HL activity at baseline was significantly higher in our population compared with an age-matched control group without type 2 diabetes (406 +/- 150 vs. 357 +/- 118 units/l). HL activity in men versus women (443 +/- 158 vs. 358 +/- 127 units/l), in carriers of the LIPC C/C allele versus carriers of the T/T allele (444 +/- 142 vs. 227 +/- 96 units/l), and in Caucasians versus blacks (415 +/- 150 vs. 260 +/- 127 units/l) all differed significantly (P < 0.001). Atorvastatin dose-dependently decreased HL (A10, -11%; A80, -22%; both P < 0.001). Neither sex nor the LIPC C-->T variation influenced the effect of atorvastatin on HL activity. CONCLUSIONS: Sex, LIPC promoter variant, and ethnicity significantly contribute to the baseline variance in HL activity. Atorvastatin treatment in diabetic dyslipidemia results in a significant dose-dependent decrease in HL activity, regardless of sex or the LIPC promoter variant.