Neutrophil gelatinase-associated lipocalin and cystatin C could predict renal outcome in patients undergoing kidney allograft transplantation: a prospective study.

Urinary neutrophil gelatinase-associated lipocalin (NGAL) may represent an early, predictive biomarker of delayed graft function due to ischemia-reperfusion injury. Unfortunately, creatinine is an unreliable indicator of acute changes in kidney function. NGAL was proposed as a novel early marker for detection of acute renal failure. Therefore, the aim of the study was to assess whether NGAL and cystatin C predicted outcomes among 41 consecutive patients undergoing kidney transplantation. Serum NGAL and cystatin C were evaluated before, as well as 1, 3, 6, and 10 days after kidney transplantation using commercially available kits. Serum creatinine was assessed at each time. We observed a significant fall in serum NGAL as early as 1 day following kidney transplantation. Serum cystatin C decreased significantly 3 days after transplantation. Before transplantation, serum NGAL was related to creatinine and cystatin C. At each time point, serum NGAL was related positively to serum creatinine, cystatin C, and negatively to urine volume. In patients with delayed graft function, there was no fall in serum NGAL or cystatin C. Our findings may have important implications for the clinical management of patients undergoing kidney transplantation. The "window of opportunity" to distinguish between acute rejection and calcineurin inhibitor nephrotoxicity is narrow in delayed graft function. Time is limited to introduce proper treatment after the initiating insult. Therefore, NGAL needs to be investigated as a potential early marker for delayed graft function, especially in the settings of early dialysis treatment or antirejection therapy.