OXIDATIVE STRESS IN HEMODIALYZED PATIENTS AND THE LONG-TERM EFFECTS OF DIALYZER REUSE PRACTICE

Objectives: To investigate the existence of an altered oxidant/antioxi dant balance in patients on regular hemodialysis treatment (RHT) and w hether there is any effect of dialyzer reuse on oxidative damage and a ntioxidative mechanism. Design and methods: Malondialdehyde (MDA) leve ls and glutathione peroxidase (GPx) activities in both plasma and eryt hrocytes, plasma selenium (Se) levels, and erythrocyte superoxide dism utase (SOD) activities of RHT patients were determined at the beginnin g and end of 4-month reuse period. Results: When compared to healthy c ontrols, both plasma and erythrocyte MDA levels were found to be signi ficantly higher in RHT patients before the dialyzer reuse practice; wh ereas both plasma and erythrocyte GPx activities, erythrocyte SOD acti vity, and also plasma Se levels were lower in the same patient group t han those of controls. When statistical comparison was made on RHT pat ients between before and after the reuse period, the decreases in MDA levels but increases in the enzyme activities and also an increase in plasma Se levels were observed after the reuse period. However, erythr ocyte SOD activities and plasma Se levels measured after the reuse per iod were not found to be statistically different from the control valu es; MDA levels still remained elevated above the control values, and G Px activities were not attained to those of controls, after the reuse practice. In addition, positive correlations were found between activi ties of erythrocyte SOD and GPx enzymes, between GPx and Se levels and negative correlations between the activities of both enzymes and MDA levels in erythrocytes of patients on RHT. Conclusion: These findings may indicate that dialyzer reuse may provide, at least partly, an impr ovement on oxidative stress in patients on RHT.