Coenzyme Q10 improves endothelial dysfunction in statin-treated type 2 diabetic patients

Abstract

OBJECTIVE - The vascular benefits of statins might be attenuated by inhibition of coenzyme Q10 (CoQ10) synthesis. We investigated whether oral CoQ10 supplementation improves endothelial dysfunction in statin-treated type 2 diabetic patients. RESEARCH DESIGN AND METHODS - In a double-blind crossover study, 23 statin-treated type 2 diabetic patients with LDL cholesterol <2.5mmol/l and endothelial dysfunction (brachial artery flow-mediated dilatation [FMD] <5.5%) were randomized to oral CoQ10 (200 mg/day) or placebo for 12 weeks. We measured brachial artery FMD and nitrate-mediated dilatation (NMD) by ultrasonography. Plasma F2-isoprostane and 24-h urinary 20-hydroxyeicosatetraenoic acid (HETE) levels were measured as systemic oxidative stress markers. RESULTS - Compared with placebo, CoQ10 supplementation increased brachial artery FMD by 1.0 ± 0.5% (P = 0.04), but did not alter NMD (P = 0.66). CoQ10 supplementation also did not alter plasma F2- isoprostane (P = 0.58) or urinary 20-HETE levels (P = 0.28). CONCLUSIONS - CoQ10 supplementation improved endothelial dysfunction in statin-treated type 2 diabetic patients, possibly by altering local vascular oxidative stress. © 2009 by the American Diabetes Association.