Urinary L-type fatty acid-binding protein is a predictor of early renal function after partial nephrectomy

Abstract

Purpose: Urinary biomarkers of renal injury urinary may identify loss of renal function following nephron-sparing surgery (NSS). This study was designed to evaluate whether urinary L-type fatty acid-binding protein (L-FABP) is an early biomarker of loss of renal function after NSS. Specifically, the kinetics of urinary L-FABP level after NSS and its correlation with factors related to ischemic renal injury were analyzed. Methods: This study prospectively evaluated 18 patients who underwent NSS between July and December 2014, including 12 who underwent laparoscopic and six who underwent robot-assisted partial nephrectomy. Urinary L-FABP concentrations were measured preoperatively and 1, 2, 3, 6, 12, 24, 48, and 72h after renal artery declamping. Loss of renal function loss was calculated by comparing the effective renal plasma flow, as determined by 99mTc-mercaptoacetyltriglycine (MAG3) clearance, on the operated and normal sides. The decrease in estimated glomerular filtration rate from before surgery to six months after surgery was also measured. Results: Urinary L-FABP concentration peaked within 2h of declamping, which may quantify nephron damage caused by ischemia. The decrease in MAG3 reduction ratio correlated with both the ischemia time and peak urinary L-FABP concentration. Peak urinary L-FABP concentration showed a significant correlation with MAG3 reduction ratio. Conclusions:L-FABP is a suitable urinary biomarker for predicting the extent of ischemic renal injury.