Antioxidant treatment in dialysis patients - importance of ferritin

Abstract

Sir, Cardiovascular disease remains one of the leading causes of mortality in haemodialysis (HD) patients. Abnormal oxidative stress and impaired antioxidant defence may contribute to accelerated atherogenesis associated with uraemia. I read with interest the article by Fumeron et al. [1], reporting that short-term oral vitamin C supplementation did not modify well-defined oxidative/antioxidative stress and inflammation markers in HD patients. As stated, they did not evaluate the effect of long-term intravenous vitamin C supplementation with lower or higher doses on oxidative stress, nor the efficacy of co-administration of vitamin E. Iron is a powerful oxidizing substance. Ferritin may have other functions in addition to its well-described role in storing intracellular iron. Elevated ferritin levels are associated with an increased risk of atherosclerotic coronary artery disease and myocardial infarction. Recent proteomics and molecular biology studies have shown that ferritin levels in arteries are increased in diseased tissues [2]. Ferritin may be unregulated under particular physiological conditions and may act as a pro-oxidant. In the mammalian cell, iron stored in ferritin can participate in initiating lipid peroxidation [3]. High levels of serum ferritin may indicate iron overload. However, in many patients results may be elevated due to inflammation, even if iron stores are not increased. Limited evidence shows that elevated iron stores and high-dose intravenous iron therapy may increase morbidity and mortality in HD patients [4], and exacerbate increased oxidative stress in uraemic patients [5].