Urine AQP5 is a potential novel biomarker of diabetic nephropathy

AimsTo investigate if urinary AQP5 serves as a new potential biomarker of diabetic nephropathy.MethodsUsing an AQP5-specific enzyme-linked immunosorbent assay, we measured serum and urine AQP5 first in a cohort consisting of normal controls (n = 26) and patients with diabetes mellitus (n = 25) or diabetic nephropathy (n = 33) and then in a validation cohort possessing normal controls (n = 10), patients with diabetes mellitus (n = 10) or diabetic nephropathy (n = 14), and patients with chronic kidney disease of unknown etiology (n = 10). We used various statistical methods including Pearson's correlation coefficient, ANOVA with Holm–Sidak test, Receiver Operator Curve, and multiple logistic regression to analyze the data.ResultsUrine AQP5/creatinine 1) is significantly higher in diabetic nephropathy than in other two groups, and in diabetic nephropathy stage V than in stage III; 2) correlates with serum creatinine, urine albumin, and multiple other known risk factors of the disease; and 3) improves the clinical models in distinguishing diabetic nephropathy from normal controls and diabetic mellitus.ConclusionOur data suggest that urine AQP5/creatinine may possess diagnostic and prognostic values as a biomarker of diabetic nephropathy.