Blood enzymes and oxidative stress in chronic kidney disease: a cross sectional study.

BACKGROUND Cardiovascular disease causes morbidity and mortality in chronic kidney disease. Increased formation of oxygen-derived radicals can accelerate the development of atherosclerosis. Several studies have shown an imbalance in antioxidant activity, resulting in high oxidative stress and lipid peroxidation, in subjects undergoing hemodialysis. METHODS Eighty-nine subjects with chronic kidney disease and varying degrees of renal impairment, some of who were undergoing peritoneal or hemodialysis, were studied and compared with a group of healthy controls. F2-isoprostanes, selenium, and oxidized low density lipoprotein (LDL) concentrations were used as markers for in vivo oxidative stress; paraoxonase and glutathione peroxidase were used as markers of antioxidant activity. RESULTS We quantified serum F2-isoprostanes, paraoxonase, selenium, oxidized LDL, and RBC glutathione and compared the treatment regimens using post-hoc pair-wise comparisons and Tukey's honest statistical difference. A significant increase in oxidative stress between the hemodialysis and control group was noted. The renal insufficiency and peritoneal dialysis groups showed increased oxidative stress and decreased antioxidant capacity, reaching statistical significance for some serum analytes. Selenium concentrations and oxidized LDL did not vary significantly between the hemodialysis and control groups. CONCLUSION These data suggest that increased oxidative stress and decreased antioxidant activity are associated with declining renal function.