Reduced superoxide dismutase activity in erythrocytes of dialysis patients: a possible factor in the etiology of uremic anemia.

Superoxide dismutase (SOD) plays a major part in the destruction of oxygen-free radicals in the body. SOD activity is impaired by several trace elements including aluminium and silicon which are found in increased levels in plasma and tissues of uremic man. SOD activity was investigated in the erythrocytes of normal controls and of dialysis patients to determine if lack of SOD-protective activity could be a contributory cause to the increased hemolysis of uremia. It was found that SOD levels in red cell hemolysate were significantly lower in dialysis patients (41.4 +/- 9.1 units/100 ml) compared to control (49.3 +/- 7.2 units/100 ml) (U = 7.3; p less than 0.005). When expressed per 100 ml of whole blood SOD levels were 3.25 +/- 0.93 units/100 ml in dialysis patients and 6.46 +/- 0.99 units/100 ml in controls (U = 96; p less than 0.001). It is concluded that inhibition of SOD activity in the erythrocytes of dialysis patients may contribute to their anemia.