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 is detectable in all type 1 diabetic patients examined (n = 48) but absent in healthy controls (n = 25), with baseline presence predicting subsequent eGFR decline (r = -0.58, p < 0.01). In DN cohorts, WT1 levels correlated with albumin-to-creatinine ratio (r = 0.60, p < 0.001) and predicted advanced disease. 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.