α-Lipoic acid (ALA) is known to improve endothelial function in patients with diabetes. However, the effect of ALA on endothelial function in hypertensive patients is unknown. The aim of this study was to investigate whether ALA improves endothelial function in diabetic and hypertensive patients.

This study included 40 patients who were treated with ALA (Group I: 20 diabetic patients, 54.9±10.2 years, Group II: 20 hypertensive patients, 56.5±9.0 years). ALA was administered in 600 mg/day doses during the first four weeks, and 1,200 mg/day doses during the second four weeks. Clinical characteristics and endothelial function were assessed at baseline, 4 weeks and 8 weeks after ALA administration. Evaluation of patients included: assessment of the brachial artery for flow mediated vasodilation (FMD) and the inflammatory marker (high sensitive CRP: hsCRP).

Clinical characteristics (body mass index, total cholesterol/HDL-cholesterol and hsCRP) were unchanged in each group. However, FMD was significantly improved at 8 weeks after ALA therapy in both groups. Group I-baseline: 4 weeks : 8 weeks = 4.1±3.3 : 6.5±2.2 : 8.0±2.7, Group II-baseline: 4 weeks : 8 weeks = 5.5±3.7 : 7.4±3.3 : 9.3±2.7, p<0.05. The level of fibrinogen was observed to have an inverse correlation with FMD at 8 weeks after ALA therapy in Group I (p<0.05).

ALA improves endothelial function in both diabetic and hypertensive patients.