title: Oxidative stress is progressively enhanced with advancing stages of CKD.
abstract: BACKGROUND
  Oxidative stress appears to have a central role in the pathophysiological process of uremia and its complications, including cardiovascular disease. However, there is little evidence to suggest how early oxidative stress starts developing during the progression of chronic kidney disease (CKD). The aim of this study is to assess oxidative stress activity in a cross-sectional study of patients with CKD stages 1 to 4.
  
  
  METHODS
  Eighty-seven steady patients (47 men, 40 women) with a median age of 62 years (range, 28 to 84 years) and mean estimated glomerular filtration rate (eGFR) of 57 mL/min (0.95 mL/s) were studied. Levels of plasma 8-isoprostanes (8-epiPGF2a) and serum total antioxidant status (TAS) were used as markers of oxidative stress. 8-epiPGF2a levels were determined by using an enzyme-linked immunosorbent assay method, whereas a chromatometric method was used to determine TAS.
  
  
  RESULTS
  Plasma 8-epiPGF2a levels increased significantly as CKD stages advanced (P < 0.001). There was a highly significant inverse correlation between 8-epiPGF2a level and GFR (P < 0.01). Serum TAS levels also increased in a similar fashion (P < 0.009) and showed a significant inverse correlation with GFR (P < 0.01). 8-epiPGF2a and TAS levels showed a positive correlation (P < 0.05). Multiple regression analysis showed that the most significant predictor variable for 8-epiPGF2a level was eGFR, whereas the association between eGFR and TAS was affected strongly by confounding variables, mainly uric acid level.
  
  
  CONCLUSIONS
  Oxidative stress appears to increase as CKD progresses and correlates significantly with level of renal function. Increased TAS seems to be dependent on several confounding variables, including increased uric acid levels, and therefore does not seem to be a reliable method for assessing the antioxidant capacity of patients with CKD. These results suggest that larger studies using the correct markers to assess the timing and complex interplay of oxidative stress and other risk factors during the progression of CKD should be carried out.
authors.affiliation: Department of Nephrology, General Hospital of Veria, Greece.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Dounousi
authors.forename: Eleni
authors.initials: E
authors.lastname: Papavasiliou
authors.forename: Areti
authors.initials: A
authors.lastname: Makedou
authors.forename: Kyriakos
authors.initials: K
authors.lastname: Ioannou
authors.forename: Konstantinos P
authors.initials: KP
authors.lastname: Katopodis
authors.forename: Alexandros
authors.initials: A
authors.lastname: Tselepis
authors.forename: Kostas C
authors.initials: KC
authors.lastname: Siamopoulos
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Tsakiris
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology; D012044:Regression Analysis; D051436:Renal Insufficiency, Chronic / Q000378:metabolism*; D014527:Uric Acid / Q000097:blood
chemical_list: D014527:Uric Acid; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost