Oxidative stress: the effect of erythropoietin and the dialysis membrane

Dialysis patients run the risk of impaired antioxidative defense and increa sed free radicals (FR) production. The study was made in order to compare F R-related parameters in ten patients treated with erythropoietin (EPO+) and ten patients not subject to this treatment (EPO-). All patients showed sta ble hemoglobin levels at > 95 g/L. FR-related parameters were monitored dur ing hemodialysis (HD) using a polysulfon (PS) or a hemophan (H) membrane fo r 12 of them (6 EPO+ a 6 EPO-). The EPO- group was found to have a higher a ctivity of superoxide dismutase (SOD, 1160 + 218 vs; 882 + 125 IU/gHb, p<0. 01) and a higher SOD/glutathione peroxidase (GSHPx) ratio compared with EPO + (30.5 +/- 7.1 vs; 21.2 + 4.8, p<0.01). A fetal of 35 healthy volunteers w ere also examined. When compared with controls EPO- showed higher SOD (p<0. 001), lower GSHPx (p<0.05) and a higher SBD/GSHPx ratio (p<0.001). Thiobarb ituric acid reacting substances in EPO+ and EPO- were comparable with the l evels found in controls. HD using H as well as PS membranes was associated with a decrease in erythrocyte glutathione levels (GSH after 30 minutes; al so for H after HD). HD using H and PS membranes resulted in a decrease in t he plasma antioxidant capacity (AOC). We can conclude that the intraerythro cyte antioxidant conditions of EPO+ patients are similar to those found in the general population and differ from those in EPO- exhibiting increased S OD and the SOD/GSHPx ratio. HD using the H as well as the PS membrane is ac companied by oxidative stress.