Urine neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker for acute canine kidney injury

Background: Biomarkers for the early prediction of canine acute kidney injury (AKI) are clinically important. Recently, neutrophil gelatinase-associated lipocalin (NGAL) was found to be a sensitive biomarker for the prediction of human AKI at a very early stage and the development of AKI after surgery. However, NGAL has not yet been studied with respect to dog kidney diseases. The application of NGAL canine AKI was investigated in this study. Results: The canine NGAL gene was successfully cloned and expressed. Polyclonal antibodies against canine NGAL were generated and used to develop an ELISA for measuring NGAL protein in serum and urine samples that were collected from 39 dogs at different time points after surgery. AKI was defined by the standard method, namely a serum creatinine increase of greater than or equal to 26.5 mu mol/L from baseline within 48 h. At 12 h after surgery, compared to the group without AKI (12 dogs), the NGAL level in the urine of seven dogs with AKI was significantly increased (median 178.4 pg/mL vs. 88.0 pg/mL), and this difference was sustained to 72 h. Conclusion: As the increase in NGAL occurred much earlier than the increase in serum creatinine, urine NGAL seems to be able to serve as a sensitive and specific biomarker for the prediction of AKI in dogs.