Erythrocyte glutathione peroxidase activity, plasma malondialdehyde and erythrocyte glutathione levels in hemodialysis and CAPD patients.

OBJECTIVES: Cardiovascular disease is the major cause of mortality in patients receiving hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) due to chronic renal failure. Increased lipid peroxidation and depletion of antioxidants may contribute to increased risk of atherosclerosis. We have therefore assessed the effect of hemodialysis and CAPD on oxidant and antioxidant status. DESIGN AND METHODS: Plasma malondialdehyde (MDA), Glutathione (GSH) levels and glutathione peroxidase (Gpx) activities were determined in 20 healthy persons (control), 20 patients on HD, 16 patients on CAPD.
RESULTS: MDA was elevated in posthemodialysis and CAPD patients in comparison to prehemodialysis and control groups (posthemodialysis 1.39 +/- 0.38 nmol/mL, CAPD 1.26 +/- 0.27 nmol/mL, prehemodilaysis 0.83 +/- 0.22 nmol/mL, controls 0.72 +/- 0.21 nmol/mL p < 0.0001). With respect to antioxidants, glutathione levels were significantly lower in prehemodialysis, posthemodialysis and CAPD groups than those in control group (prehemodialysis 16.82 +/- 6.73 mg/dL RBC, posthemodialysis 31.43 +/- 11.88 mg/dL RBC, CAPD 40 +/- 12.72 mg/dL RBC, controls 62.26 +/- 24.01 mg/dL RBC, p < 0.0001). While erythrocyte GSH levels were significantly lower in the prehemodialysis patients than those in posthemodialysis and CAPD patients (p < 0.0001), it was significantly lower in posthemodialysis patients than those in CAPD patients (p < 0.05). There were no significant differences with respect to erythrocyte Gpx levels among the groups (p > 0.05).
CONCLUSIONS: These findings indicate oxidative stress in patients with chronic renal failure which is further exacerbated by hemodialysis and CAPD, as evidenced by increased lipid peroxidation and low antioxidant levels.