Effects of a vitamin E-modified dialysis membrane and vitamin C infusion on oxidative stress in hemodialysis patients.

Hemodialysis deteriorates oxidative stress. Vitamin E is an antioxidant whose regeneration is provided for by vitamin C. The authors tested the effects of a vitamin E-modified membrane (E), nonmodified cellulose membrane (O), and vitamin C infusion (500 mg, C) into the arterial blood line during dialysis on parameters of oxidative stress. In a short-term study, 24 patients were subjected to a single dialysis session with E, O, E with C, and O with C protocols. In a long-term study (12 weeks), 20 patients were randomized into groups with C and without C on each dialysis, and both groups had dialysis using O, E, and again O membrane for 4 weeks each. In the short-term study, thiobarbituric acid reacting substances (TBARS) in plasma rose after dialysis (p < 0.02) with O, and no changes were observed in the other 3 protocols. In the long-term study, predialysis TBARS declined when using E both in the groups with C (p < 0.02) and without C (p < 0.05). A switch over to O resulted in TBARS returning to baseline levels. The E membrane prevented an increase in lipid peroxidation during single dialysis, and long-term use of the E membrane also resulted in a decrease in the predialysis lipid peroxidation level. The antioxidant capacity of the E membrane was not enhanced by vitamin C infusion. High doses of vitamin C administered during dialysis using a nonmodified cellulose membrane prevented an increase in lipid peroxidation, most probably due to the enhanced rate of endogenous vitamin E regeneration.