Novel aspects of vitamin C in epoetin response.
Provision of sufficient available iron is a prerequisite to ensure the bodys optimal response to recombinant human erythropoietin (epoetin). Functional iron deficiency (a state when iron supply is reduced to meet the demands for increased erythropoiesis) is a common cause of poor response to epoetin in dialysis patients who have normal iron status, even when they are iron-overloaded. Iron supplementation is not justified for this hyporesponsiveness in patients with iron overload due to the potential hazards of iron overload aggravated by intravenous iron therapy. Furthermore, in vivo studies have indicated that the promising effect of intravenous iron medication to overcome iron-deficient erythropoiesis is not observed in iron-overloaded hemodialysis (HD) patients. Vitamin C, a water-soluble antioxidant as well as a reducing agent, has a number of associations with iron metabolism. Recent research highlights that vitamin C can potentiate the mobilization of iron from inert tissue stores and facilitates the incorporation of iron into protoporphyrin in HD patients being treated with epoetin. Interest has turned towards the use of vitamin C as an adjuvant therapy in this field. This review focuses on the improvement of epoetin response by administration of vitamin C and discusses its clinical implications and potential issues for internal medicine doctors.
Tarng
Der-Cherng
DC
Department of Physiology and Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC. dctarng@vghtpe.gov.tw
D000284:Administration, Oral; D000740:Anemia / Q000188:drug therapy*; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000009:adverse effects; D004921:Erythropoietin / Q000627:therapeutic use*; D006801:Humans; D007275:Injections, Intravenous; D011994:Recombinant Proteins; D006435:Renal Dialysis
D011994:Recombinant Proteins; D004921:Erythropoietin; D001205:Ascorbic Acid