Utility of urinary tubular markers for monitoring chronic tubulointerstitial injury after ischemia-reperfusion.

Abstract

The aim of this study was to elucidate whether urinary tubular markers during the chronic phase of acute kidney injury (AKI) are associated with chronic tubulointerstitial damage. Male human L-type fatty acid binding protein (L-FABP) chromosomal transgenic (Tg) mice underwent ischaemic reperfusion (I/R) injury via renal pedicle clamping for either 10min or 20min. Contralateral nephrectomy was performed at the time of tissue reperfusion. The kidneys were analyzed 20days after the last I/R. Serum creatinine levels 20days post-I/R were significantly higher in the 20min I/R than in the 10min I/R and control groups and were similar between the 10min I/R and control groups. The degree of tubulointerstitial damage 20days post-I/R was significantly more severe in the 20min I/R than in the 10min I/R and control groups, as well as in the 10min I/R than in the control group. Urinary levels of human L-FABP, albumin, and kidney injury molecule-1 (KIM-1) 20days post-I/R were significantly higher in the 20min I/R than in the control group, whereas urinary L-FABP was significantly higher in the 10min I/R than in the control group. Conversely, urinary neutrophil gelatinase-associated lipocalin levels did not significantly differ between the three groups. Finally, the urinary levels of human L-FABP, albumin, and KIM-1 levels 20days post-I/R were significantly correlated with the degree of renal damage. Urinary levels of human L-FABP, albumin and, KIM-1 may be useful for monitoring AKI-to-CKD transition in clinical practice.