Erythrocyte defense mechanisms against free oxygen radicals in haemodialysed uraemic children

Changes in erythrocyte lipid peroxidation (measured as the concentration of malonyl dialdehyde), glutathione metabolism, antioxidant enzyme activities (glutathione peroxidase, catalase, and superoxide dismutase), the oxidized products of haemoglobin (Hb), and hydrogen peroxide (H2O2)-induced haemolysis were studied in six children with chronic renal failure treated with serial acetate and bicarbonate haemodialysis (HD). Ten age- and sex-matched children acted as controls. Malonyl dialdehyde levels were significantly higher and antioxidant enzyme activities lower in uraemic red blood cells (RBCs) compared with controls (P<0.05). Incubation of RBCs for 1 h with acetylphenylhydrazine induced a decrease in the concentration of reduced glutathione (P<0.001) and an increase in the level of oxidized products of Hb (P<0.001), but only in the uraemic patients. The H2O2 haemolysis test revealed a mild (n=3) to increased (n=3) haemolysis in the uraemic RBCs. Oxidative haemolysis is probably a multifactorial process in uraemic patients, and may be an important risk factor in HD therapy.