Effect of intravenous vitamin C on cytokine activation and oxidative stress in end-stage renal disease patients receiving intravenous iron sucrose

Abstract

Reticuloendothelial blockade in hemodialysis patients prevents optimal intravenous (IV) iron utilization. Vitamin C has emerged as a potential therapy to improve anemia treatment by enhancing iron mobilization. However, Vitamin C can act as a pro-oxidant in the presence of iron. This was a prospective, open-label, crossover study. Thirteen patients with end-stage renal disease on hemodialysis and four healthy controls were assigned to receive 100mg of IV iron sucrose (IS) or 100mg of IV IS co-administered with 300mg of IV Vitamin C (IS+C) in random sequence. Serum samples for IL-1, IL-6, TNF-α and IL-10 and non-transferrin bound iron were obtained at baseline, 45min and 105min post study medication administration. Peripheral blood mononuclear cells were isolated at the same time points and stained with fluorescent probes to identify intracellular reactive oxygen species and mitochondrial membrane potential (Δψm) by flow cytometry. Lipid peroxidation was assessed by plasma F2-isoprosatane concentration. Both IS and IS+C were associated with increased plasma F2-isoprostanes concentrations post-infusion. Maximal plasma F2-isoprostane concentrations after IS+C were significantly elevated from baseline (234±0.04 vs. 0.198±0.028ng/mL, p=0.02). After IS+C, IL-1, IL-6, IL-10, and TNF-alpha were significantly elevated compared to baseline. After IS alone only IL-6 was noted to be elevated. Intracellular production of H(2)O(2) and loss of mitochondrial membrane potential (Δψm) was observed after IS while IS+C was associated with increased O (2) (·-) production. Both IS and IS+C induced serum cytokine activation accompanied by lipid peroxidation, however, IS+C induced higher plasma concentrations of F2-isoprostanes, IL-1, IL-10, and TNF-α post-infusion. Long-term safety studies of IV iron co-administered with Vitamin C are warranted.