Wilms' tumor 1 in urinary exosomes as a non-invasive biomarker for diabetic nephropathy

Diabetic nephropathy (DN) is a major cause of end-stage renal disease, with podocyte injury representing an early pathogenic event. Conventional biomarkers such as albuminuria and eGFR identify renal damage only at advanced stages, limiting opportunities for timely intervention. Wilms' Tumor 1 (WT1), a podocyte-specific transcription factor, has emerged as a sensitive marker of early glomerular stress. Earlier studies show that urinary exosomal WT1 was detected in 33 of 48 type 1 diabetic patients but only in 1 of 25 healthy controls. WT1 levels correlated positively with albumin-to-creatinine ratio (r = 0.89, p < 0.001), and inversely with eGFR (r = -0.62, p < 0.001). Moreover, WT1 predicted reduced renal function (eGFR < 60 ml/min/1.73 m²) with high accuracy (AUC = 0.92). Animal studies further demonstrated that exosomal WT1 rises before albuminuria and declines with therapy. These findings position urinary exosomal WT1 as a non-invasive, podocyte-specific biomarker for early detection and monitoring of DN.