Urinary L-type fatty acid-binding protein as a new renal biomarker in critical care

Acute kidney injury (AKI) remarkably increases the mortality of critically ill patients treated in ICUs. Recently, several renal biomarkers have been developed for the early detection of AKI. We review the potential of urinary L-type fatty acid-binding protein (L-FABP) as a new renal biomarker for AKI diagnosis in critical care.

In the kidney, L-FABP is expressed in renal proximal tubular epithelial cells and shed into urine rapidly in response to renal insults. By using human L-FABP transgenic mice, we reported that urinary L-FABP can detect AKI sensitively and reflect its severity accurately in animal models of AKI and sepsis. In clinical evaluations, the good performance of urinary L-FABP was demonstrated not only in pediatric postcardiopulmonary bypass surgery AKI and contrast media-induced AKI but also in septic shock patients complicated with AKI.

Recent data suggest that urinary L-FABP can contribute to the development of new AKI diagnostic tools in critical care. Combining with other renal markers such as neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1), optimal threshold determination for distinguishing AKI from chronic renal failure should be explored before translation to the clinical.