alpha-lipoic acid decreases oxidative stress even in diabetic patients with poor glycemic control and albuminuria

In the present cross-sectional study, the influence of alpha-lipoic acid on markers of oxidative stress, assessed by measurement of plasma lipid hydro peroxides (ROOHs), and on the balance between oxidative stress and antioxid ant defence, determined by the ratio ROOH/(alpha-tocopherol/cholesterol), w as examined in 107 patients with diabetes mellitus. Patients receiving alph a-lipoic acid (600 mg/day for > 3 months) had significant lower ROOHs and a lower ROOH(alpha-tocopherol/cholesterol) ratio than those without alpha-li poic acid treatment [ROOH: 4.76 +/- 2.49 vs. 7.16 +/- 3.22 mu mol/l; p <.00 01] and [ROOH/(alpha-tocopherol/cholesterol): 1.37 +/- 0.72 vs. 2.16 +/- 1. 17; p < 0.0001]. In addition, the influence of glycemic control and albumin uria on ROOHs and on the ratio of ROOH/(alpha-tocopherol/cholesterol) was e xamined in the presence and absence of alpha-lipoic acid treatment. Patient s were subdivided into three groups based on (1) their HbA(1) levels (<7.5, 7.5-9.5, and >9.5%) and (2) their urinary albumin concentrations (<20, 20- 200, and >200 mg/l). Neither poor glycemic control, nor the presence of mic ro- or macroalbuminuria prevented the antioxidant effect of alpha-lipoic ac id. Using stepwise multiple regression analysis, alpha-lipoic acid was foun d to be the only factor significantly predicting low ROOHs and a low ratio of ROOH/(alpha-tocopherol/ cholesterol). These data provide evidence that t reatment with alpha-lipoic acid improves significantly the imbalance betwee n increased oxidative stress and depleted antioxidant defence even in patie nts with poor glycemic control and albuminuria. (C) 1999 Elsevier Science I nc.