Neutrophil gelatinase-associated lipocalin as an early biomarker of acute kidney injury in liver transplantation

Background: Acute kidney injury (AKI) is a common complication and a significant prognostic factor of long-term outcome in patients undergoing liver transplantation. We evaluated the utility of urine and plasma neutrophil gelatinase-associated lipocalin (NGAL) concentrations as biomarkers of AKI during and after liver transplantation. Materials and methods: We prospectively enrolled 19 adult patients who underwent living-related liver transplantation (LRLT). Serial blood and urine samples were collected at baseline and at 2, 4, 10, 16, 24, 30, 40, and 48 h after reperfusion, and their concentrations of NGAL were measured, with urinary NGAL corrected by urinary creatinine concentration to compensate for urine output. AKI was defined by Risk-Injury-Failure-Loss-End-stage kidney disease (RIFLE) criteria as a ≥50% increase in serum creatinine from baseline. Results: Eleven of 19 patients were diagnosed with AKI according to RIFLE criteria. Urinary NGAL/urine creatinine ratio increased immediately after reperfusion and peaked four h later and preceded a ≥50% elevation in serum Cr by 19.0 h (p = 0.001). Plasma NGAL also tended to be elevated 13.0 h earlier than serum creatinine (p = 0.075). Conclusions: The urinary NGAL/urine creatinine ratio may be an early biomarker of AKI in adult patients undergoing LRLT.