TOTAL ANTIOXIDANT CAPACITY (TAC) - IS IT AN EFFECTIVE METHOD TO EVALUATE THE OXIDATIVE STRESS IN UREMIA

Lipoprotein abnormalities are common in uraemia and are considered imp ortant factors for development of atherosclerosis and progression of r enal disease. Reduction of total antioxidant capacity (TAC) and lipid peroxidation (LP) probably play a major role in both processes. The ai m of this study was to assess the effect of renal function, dietary ma nipulation and lipids on TAC of uraemic patients with different chroni c renal failure (CRF). Sixty patients (36M, 24F), aged 60 +/- 12 years were divided into five groups according to serum creatinine levels (s Cr,mg/dl)- CRFI, 1.5-3; CRFII, >3-5.5; CRFIII, >5.5; CRFIV, >3 on vege tarian supplemented diet (SD); CRFV haemodialysis patients (HD)-and in vestigated for TAC by enhanced chemiluminescent assay, autoantibodies against oxidized LDL (oxLDLAb), lipids, apolipoprotein Al, B, Lp(a) an d uric acid (UA). The results were compared to a control group of 19 p eople (8M, 11F). aged 52 +/- 11 years with sCr < 1.5. TAC increased si gnificantly with the progression of CRF and was strongly related to bo th sCr end UA. Lipids and SD did not show any influence on TAG. Unexpe ctedly, lipid peroxidation did not correlate to TAG, neither to sCr or UA. HD accounted for a mild reduction of both TAC and LP. Patients on SD showed a marked reduction of LP as compared to patients with a sim ilar degree of renal failure (CRF-III) but on conventional diet. Our r esults suggest that elevated TAC in uraemia is likely to be dependent on increased UA levels and does not: seam to induce an effective prote ction in vivo from oxidative stress. In conclusion, TAC does not appea r to be a reliable method for assessing the oxidative susceptibility o f CRF patients. (C) 1998 John Wiley & Sons, Ltd.