Vitamin E alleviates the oxidative stress of erythropoietin in uremic children on hemodialysis.

The efficacy of combined therapy with recombinant human erythropoietin (rhEPO) and vitamin E versus rhEPO alone in the treatment of anemia was examined in children (n = 10, aged 15.2 +/- 3.2 years) on chronic hemodialysis at the restart of rhEPO therapy after a 4-week interval. The results confirmed that rhEPO induced oxidative stress of the red blood cells as observed during the first rhEPO therapy. Vitamin E (15 mg/kg per day per os) was introduced after 2 weeks of rhEPO monotherapy, when the signs of acute oxidative stress appeared. The level of oxidized glutathione (GSSG) increased from 8.9 +/- 3.1 to 26.7 +/- 5.7 nmol/g hemoglobin (Hb) by that time. After 2 weeks of simultaneous vitamin E treatment, there was a significant difference in GSSG values compared with rhEPO monotherapy (10.1 +/- 3.9 vs. 56.7 +/- 15.8 nmol/g Hb, P < 0.001). A considerable decrease was observed in the previously high ratio of GSSG/reduced glutathione (GSH), an indicator of oxidative stress, and the level of carboxyhemoglobin, indicating hemolysis. A significant increase in Hb and hematocrit (P < 0.01) was achieved within 2 weeks of starting the combined therapy, while similar results occurred only at the 8th and 5th weeks without vitamin E. Antioxidant vitamin E supplementation improved the therapeutic effect of rhEPO in patients with chronic renal failure on hemodialysis.