title: Alteration in plasma antioxidant capacity in various degrees of chronic renal failure.
abstract: OBJECTIVE
  To obtain a more comprehensive profile of extracellular antioxidant capacity in chronic renal failure (CRF), markers of oxidative stress (malondialdehyde, MDA and hydrogen peroxide), protein SH groups (as an important chain-breaking antioxidant) and activity of antioxidant enzymes (glutathione peroxidase, [GPX], catalase and superoxide dismutase, [SOD]) were studied in plasma of 36 non-dialyzed patients with various degrees of CRF and 10 hemodialyzed (HD) patients.
  
  
  RESULTS
  The results show that plasma MDA concentrations significantly increase with the severity of kidney dysfunction (r = -0.543, p < 0.01). A marked and profound fall in plasma thiol group levels was observed in all groups tested, independent of the degree of renal failure (r = 0.082, p > 0.05). Plasma SOD activity increased in CRF patients with the progression of renal insufficiency (r = -0.370, p < 0.05). On the other hand, plasma GPX activity decreased progressively in strong correlation with endogenous CCr (r = 0.712, p < 0.001). However, despite this imbalance between extracellular SOD and GPX activities, plasma concentration of hydrogen peroxide remained unchanged in non-dialyzed CRF patients. Catalase activity in non-dialyzed CRF patients was increased, suggesting the significant involvement of catalase in the regulation of plasma hydrogen peroxide level.
  
  
  CONCLUSIONS
  In hemodialyzed patients significantly lower plasma catalase activity, associated with higher hydrogen peroxide levels, was found. It seems reasonable to assume that the imbalance in the activity of extracellular antioxidant enzymes in chronic renal failure may result in accumulation of free radical species, and in unscheduled oxidation of susceptible molecules.
authors.affiliation: Institute of Biochemistry, Faculty of Medicine, Belgrade, Yugoslavia.
authors.forename: J
authors.initials: J
authors.lastname: Mimić-Oka
authors.forename: T
authors.initials: T
authors.lastname: Simić
authors.forename: L
authors.initials: L
authors.lastname: Djukanović
authors.forename: Z
authors.initials: Z
authors.lastname: Reljić
authors.forename: Z
authors.initials: Z
authors.lastname: Davicević
mesh_terms: D000368:Aged; D000975:Antioxidants / Q000032:analysis*; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy; D015227:Lipid Peroxidation; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D006435:Renal Dialysis
chemical_list: D000975:Antioxidants; D015415:Biomarkers