Oral Vitamin C Supplementation in Hemodialysis Patients and Its Effect on the Plasma Level of Oxidized Ascorbic Acid and Cu/Zn Superoxide Dismutase, an Oxidative Stress Marker

Abstract

Background/Aim: Oxidative stress is known to be enhanced in hemodialysis patients, and one of its useful markers is plasma copper/zinc superoxide dismutase (Cu/Zn-SOD). The increase in plasma Cu/Zn-SOD can be inhibited by orally administered lipid-soluble vitamin E. We examined the antioxidative effects of water-soluble vitamin C administered orally on Cu/Zn-SOD levels in hemodialysis patients. Methods: Vitamin C was orally administered to 16 maintenance hemodialysis patients before each dialysis session. Doses were increased from 200 to 1,000 mg over 3 months. The levels of plasma vitamin C and Cu/Zn-SOD and its mRNA expression in leukocytes were determined 1, 2, and 3 months after the start of vitamin C administration. Furthermore, the levels of oxidized and reduced forms of plasma vitamin C were determined before the start of vitamin C administration and before and after dialysis at 1,000-mg vitamin C doses. Results: Following oral administration, the plasma levels of vitamin C and its oxidized form were increased. However, significant changes in plasma Cu/Zn-SOD or its mRNA expression in leukocytes were not observed. Conclusion: In maintenance hemodialysis patients, vitamin C administration resulted in a significant increase in the postdialysis level of the oxidized form of vitamin C, which suggested an increase in antioxidant effect. However, water-soluble vitamin C did not significantly suppress Cu/Zn-SOD expression enhancement.

Effect of combined vitamins C and E supplementation on oxidant/antioxidant status in hemodialysis patients

“…In the present study, supplementation with a combined vitamins C and E significantly elevated serum vitamin E, consistent with some studies [24][25][26][27], but its results are unlike Hultquist results [23].…”

Effect of diabetes and oxidative stress on plasma CCL23 levels in patients with severe chronic kidney disease

“…SOD serves as an antioxidant enzyme responsible for superoxide removal, and its increase may represent a compensatory response to oxidative stress. 25 The plasma level of the cytosol isoform SOD (Cu/Zn SOD) has been reported as a useful oxidative stress marker in uremic patients in our previous study 26 and in a study by Washio et al 27 In the present study, in patients with CKD, multiple regression analysis was performed on the basis of the results of Spearman rank correlation in all patients with CKD (groups A and B) as well as in a subgroup of patients with CKD and without diabetes (TAbLE 3). The presence of diabetes, Cu/Zn SOD levels, and the percentage of lymphocytes in WBC were found to be significant independent factors affecting plasma CCL23 concentrations in the whole CKD group (r 2 for the model = 0.573).…”

Vitamin E as a Functional and Biocompatibility Modifier of Synthetic Hemodialyzer Membranes: An Overview of the Literature on Vitamin E-Modified Hemodialyzer Membranes

“…A pioneering study by Akiyama et al [81] showed the same effect of these treatments on the expression of the antioxidant enzyme Cu-Zn superoxide dismutase in circulating mononuclear leukocytes of HD patients, which may represent a new in vivo oxidative stress biomarker associated with lipid oxidation of leukocyte plasmalemma [80]. Interestingly, this biomarker does not appear to be affected by the oral supplementation with the hydrosoluble antioxidant vitamin C [94]. This early evidence paves the way to a specific role of vitamin E therapy in the protection of circulating leukocytes, which deserves further clinical investigation in CKD patients on regular HD therapy.…”