REDOX STATE, ANTIOXIDATIVE ACTIVITY AND LIPID-PEROXIDATION IN ERYTHROCYTES AND PLASMA OF CHRONIC AMBULATORY PERITONEAL-DIALYSIS PATIENTS

Red blood cells and plasma reduced and oxidized glutathione levels, gl utathione peroxidase (GSH-Px) activity, thiobarbituric acid reactants (TBAR) of both chronic ambulatory peritoneal dialysis (CAPD) patients and a matched control group were investigated in this study. Oxidized and reduced pyridinic nucleotides in red blood cells (RBC), in which N ADPH is a direct expression of hexose monophosphate shunt function, we re also studied. The results obtained indicate that RBC and plasma are exposed to oxidative stress in CAPD. This condition is characterized by a decreased GSH/GSSG ratio, particularly evident in RBC as a conseq uence of the GSSG accumulation. Lipid peroxidation is increased, as in dicated by raised TBAR levels, and reduced pyridinic nucleotides are d ecreased. Increased GSH-Px levels and unmodified or slightly increased GSH content were observed in the RBC but not in plasma, which showed decreased GSH and unmodified peroxidase activity. Peroxidase correlate d positively with TBAR levels in the RBC lysates. In a subgroup of pat ients treated with erythropoietin (vs. untreated patients and controls ) no differences were observed in the glutathione-related parameters s tudied. These data suggest that a mechanism for adaptation to oxidativ e conditions may be present in CAPD and its effects on RBC integrity a re discussed in comparison with the hemodialysis conditions previously studied.