Does treatment of renal anemia with recombinant erythropoietin influence oxidative stress in hemodialysis patients?

Patients with chronic renal failure (CRF) undergoing hemodialysis (HD) are exposed to constant oxidative stress, as shown by elevated malondialdehyde (MDA) plasma concentrations in HD patients. The aim of our study was to investigate the role of renal anemia in oxidative stress. To this end, MDA and 4-hydroxynonenal (HNE) were measured in three groups of patients. Group I comprised 8 patients with hemoglobin (Hb) < 10 g/dl (mean Hb 8.1 +/- 1.3 g/dl) and group II 8 patients with Hb > 10 g/dl (mean Hb 12.4 +/- 1.9 g/dl). None of these 16 patients had been previously treated with recombinant erythropoietin (rhEPO). Group III comprised 27 patients with mean Hb 10.5 +/- 1.6 g/dl after long-term treatment with rhEPO. The plasma concentrations of both MDA and HNE in all 43 HD patients were significantly higher (p < 0.0001) than in 20 healthy controls (MDA 2.85 +/- 0.25 vs 0.37 +/- 0.03 microM, HNE 0.32 +/- 0.03 versus 0.10 +/- 0.01 microM). Comparison between the three groups showed that the HD patients with Hb < 10 g/dl had significantly higher plasma concentrations of lipid peroxidation products (MDA 3.81 +/- 0.86 microM, HNE 0.45 +/- 0.07 microM) than either HD patients with Hb > 10 g/dl (MDA 2.77 +/- 0.58 microM, HNE 0.25 +/- 0.05 microM) or HD patients treated with rhEPO (MDA 2.50 +/- 0.12 microM, HNE 0.29 micro 0.03 microM). An inverse correlation was also demonstrated between plasma HNE and Hb (r= 0.62, p < 0.0001). It follows that a substantial part of the oxidative stress is due to renal anemia. Treatment with rhEPO can therefore effectively reduce oxidative stress in HD patients.