Urinary heat shock protein 72 as a biomarker of acute kidney injury in dogs

Early recognition of acute kidney injury (AKI) is important, as therapy is potentially more efficacious if instituted early in the course of disease. Urinary heat shock protein-72 to urinary creatinine ratio (uHSP72/uCr) was assessed as a diagnostic and prognostic marker in AKI in dogs. Fifty-three dogs were enrolled in five groups: healthy controls (n = 11), urinary tract infection (n = 10), chronic kidney disease (CKD; n = 11), AKI (n = 13), and acute decompensating CKD (n = 8). Urinary heat shock protein-72 to urinary creatinine ratio was highest in the AKI group (P < 0.001 when compared to the control and urinary tract infection groups, individually; P > 0.05 compared to each of the other two groups). The area under the curve (AUC) for the receiver operator characteristic (ROC) analysis of uHSP72/uCr to predict AKI, compared to the control group, was 0.97. A cutoff value of 0.20 ng/mg corresponded to sensitivity and specificity of 100% and 82%, respectively. Urinary heat shock protein-72 to urinary creatinine ratio was significantly lower in dogs categorized as survivors vs. non-survivors of AKI; ROC AUC, 0.91 (95% confidence intervals, 0.74–1.0). Urinary heat shock protein-72 to urinary creatinine ratio is a potentially useful diagnostic and prognostic biomarker of AKI in dogs.