Effect of different dialysis membranes on erythrocyte antioxidant enzyme levels and scavenger systems related to free hemoglobin in serum of hemodialysis patients.

The main objective of the present study was to analyze some aspects of the function and structure of erythrocytes with respect to hemodialysis membrane biocompatibility throughout the erythrocyte and serum antioxidant levels. The study included 36 hemodialysis patients (14 female and 22 male, age 22-79 years, median 55) treated at the Department of Nephrology and Dialysis, Split Clinical Hospital in Split, and 30 control subjects matched for age and sex. Hemodialysis was performed three times a week for 4 hours with cellulose diacetate (n = 17; 6 females and 11 males) or polysulfone (n = 19; 8 females and 11 males) membranes. The aim of the study was to assess the level of oxidative stress in these patients by measuring catalytic concentrations of superoxide dismutase and glutathione peroxidase in erythrocyte lysate and scavenger systems related to free hemoglobin in serum (haptoglobin, hemopexin and bilirubin). In comparison with control values, the mean catalytic concentrations of superoxide dismutase were increased and catalytic concentrations of glutathione peroxidase decreased in patients before hemodialysis irrespective of the membrane used. Immediately after hemodialysis with either membrane, the mean catalytic concentrations of superoxide dismutase returned to the control range, while those of glutathione peroxidase were still decreased compared to control values, without any significant difference between the cellulose diacetate and polysulfone membranes. The predialysis and postdialysis values of haptoglobin, hemopexin and bilirubin in patient sera were within the range of control values. Comparison of the cellulose diacetate and polysulfone membranes showed no significant differences in the erythrocyte content of antioxidant enzymes and the scavenger system related to free hemoglobin in serum before and after hemodialysis.