Atorvastatin but not L-arginine improves endothelial function in type I diabetes mellitus: A double-blind study

OBJECTIVES We sought to determine the effects of oral L-arginine and the he xamethyglutaryl coenzyme A reductase inhibitor atorvastatin on endothelial function in young patients with type I diabetes mellitus (DM). BACKGROUND Endothelial dysfunction, a key early event in atherosclerosis, o ccurs in young patients with type I DM, and its reversal may benefit the pr ogression of vascular disease. Cholesterol reduction in L-arginine improve endothelial function in nondiabetic subjects, but their effect in patients with type I DM is unknown. METHODS In a double-blind, 2 X 2 factorial study, we investigated the effec t of L-arginine (7 g twice daily) and atorvastatin (40 mg/day) on conduit a rtery vascular function in 84 normocholesterolemic young adults (mean +/- S D: age 34 rears [range 18 to 46], low density lipoprotein [LDL] cholesterol 2.96 +/- 0.89 mmol/liter) with type I DM. Brachial artery dilation to flow (flow-mediated dilation [FMD]) and to the direct smooth muscle dilator gly ceryl trinitrate (GTN) were assessed noninvasively using high resolution ul trasound at baseline and after six weeks of treatment. RESULTS Atorvastatin resulted in a 48 +/- 10% decrease in serum LDL cholest erol levels, whereas L-arginine levels increased by 247 +/- 141% after L-ar ginine therapy. By analysis of covariance, treatment with atorvastatin resu lted in a significant increase in FMD (p = 0.018. L-Arginine therapy had no significant effect on endothelial function, and there was no significant c hange in dilation to GTN after either intervention. CONCLUSIONS In young patients with type I DM, improvement in endothelial dy sfunction can be demonstrated after just six weeks of treatment with atorva statin. In contrast to studies of hypercholesterolemia, however, L-arginine had no benefit. Treatment with atorvastatin at an early stage may have an impact on the progression of atherosclerosis in these high risk patients. ( C) 2000 by the American College of Cardiology.