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.