Comparison of effect of vitamin E-coated dialyzer and oral vitamin E on hemodialysis-induced Cu/Zn-superoxide dismutase

BACKGROUND: We reported earlier that production of Cu/Zn-superoxide dismutase (SOD) increases markedly in hemodialysis patients but not in non-dialyzed chronic renal failure (CRF) patients. In this study, we compared the antioxidant effects of oral vitamin E supplementation (VE-PO) and vitamin E coating of a dialyzer (VE-BMD) by measuring increased Cu/Zn-SOD in hemodialysis patients. METHODS: 31 hemodialysis patients were divided into two groups: 16 hemodialysis patients underwent usual dialysis with vitamin E supplementation 600 mg/day while 15 others were dialyzed using vitamin E-coated membrane for 6 months. Total plasma SOD activity was determined by NBT method, plasma Cu/Zn-SOD contents by ELISA and Cu/Zn-SOD mRNA in leukocytes by RT-PCR. RESULTS: VE-PO and VE-BMD showed almost comparable effects on Cu/Zn-SOD contents and its mRNA levels in hemodialysis patients. VE-PO resulted in a progressive decrease of Cu/Zn-SOD content (p < 0.001). A comparable progressive decrease was observed also in VE-BMD (p < 0.0001). Both VE-PO and VE-BMD resulted in a progressive decrease of Cu/Zn-SOD mRNA (p < 0.01), which reached the level of non-dialyzed CRF patients.