Abstract
Diabetic nephropathy (DN) represents the primary cause of end-stage renal disease worldwide, yet current clinical modalities—specifically urinary albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR)—fail to detect subclinical renal cellular injury prior to irreversible structural damage. Urinary exosomes encapsulate molecular signatures derived directly from nephron epithelial cells, preserving fragile microRNAs (miRNAs) from enzymatic degradation. In this cross-sectional study, we investigated the clinical utility of a targeted urinary exosomal miRNA panel (miR-21-5p, miR-29c-3p, and miR-192-5p) for the early detection of DN in 210 patients with type 2 diabetes mellitus (T2DM), categorized into normoalbuminuric (n=80), microalbuminuric (n=70), and macroalbuminuric (n=60) cohorts, alongside 50 healthy controls. Urinary exosomes were isolated via differential ultracentrifugation and characterized using nanoparticle tracking analysis, transmission electron microscopy, and Western blotting for tetraspanin markers (CD63, CD9). Expression profiles quantified by reverse transcription-quantitative polymerase chain reaction demonstrated significant dysregulation: miR-21-5p was progressively upregulated across stages, whereas miR-29c-3p and miR-192-5p were markedly depleted. Crucially, in normoalbuminuric T2DM patients, the combined three-miRNA panel demonstrated an area under the receiver operating characteristic curve (AUC) of 0.884 (95% CI: 0.821–0.947), significantly outperforming individual miRNAs and conventional screening parameters. Multivariate logistic regression confirmed the panel as an independent predictor of early renal involvement. These findings underscore that urinary exosomal miRNA profiling provides a non-invasive, highly sensitive liquid biopsy capable of identifying subclinical diabetic glomerulopathy, thereby establishing a window for timely therapeutic intervention.
