Oxidant Stress in Urine From Cadaveric and Living Kidney Donors as Markers of Renal Injury

This is the authors' abstract. We don't add key points for this paper.

277 Introduction: The preoperative assessment of marginal extended cadaveric donors is based upon the imprecise parameters of clinical history and serum creatinine (Cr). Markers of oxidant stress reflect inflammatory and ischemic injury in several disease states, including renal failure. We wished to measure markers of oxidant stress in brain dead and living renal donors. Methods: Urine was collected from 17 brain dead cadaveric donors at the time of organ procurement as well as from 8 healthy living related donors. Samples were frozen at −20°C until used. Total antioxidant capacity was measured by the TRAP method (based upon oxidation of methemoglobin) and reported as Trolox equivalents. Isoprostane (8-isoprostane-2-α) as a marker of lipid peroxidation was measured by an enzymatic immuno-assay (Caymen) and corrected for urine creatinine. Poor donors were defined as those with a serum creatinine > 2.0 mg/dl and/or pathologic changes on renal biopsy which precluded use for transplantation. Results: By clinical criteria there were 7 good donors, 10 poor donors and 8 healthy control donors. Isoprostane levels were highest in poor donors (1033 pg/mgCr +/− 310) compared with good donors (982 pg/mgCr +/− 147) and normals (700 pg/mgCr +/− 120) however statistical significance was not achieved due to the wide variances. Antioxidant capacity however was significantly lower in urine from poor donors (0.66 mM +/− .15) vs good donors (1.44 +/− .22) or normals (1.03 +/− .23) (p<0.05). Based on clinical outcome, the antioxidant capacity of donors when both kidneys had early graft function in the recipients (1.5mM +/− .22) was significantly higher than when both kidneys had delayed graft function (0.52mM +/− .06) or were not transplanted (0.75mM +/− .19)(p<0.05). Serial measurements in the transplant recipients showed increased isoprostane levels on day 2 after transplant associated with a drop in antioxidant capacity, both of which normalized as renal function improved. Conclusion: Decreased total antioxidant capacity of urine from renal donors correlates with pre-existing renal injury and is predictive of delayed graft function in the recipient. Isoprostane levels are elevated in brain dead donors regardless of renal function. Both tests may be useful in post-transplant monitoring.