Urinary extracellular vesicles: Toward non-invasive biomarker discovery in kidney graft monitoring

Urinary extracellular vesicles (uEVs) have emerged as a promising and versatile source of non-invasive biomarkers for kidney allograft monitoring. This review summarizes current evidence on uEV-derived biomarkers, including proteins, gene expression signatures, microRNAs, and extracellular vesicle-associated DNA, highlighting their potential role in detecting allograft rejection, calcineurin inhibitor nephrotoxicity, and progressive graft dysfunction. Urinary EVs reflect molecular processes occurring within the graft, including immune activation, metabolic dysregulation, and tissue remodelling. Consequently, the analysis of uEVs may offer real-time information on graft status through a readily accessible biological fluid, complementing conventional surveillance strategies and enabling earlier detection of allograft injury. For kidney transplant recipients. The effective uEV translation into clinical practice will require a collective efforts to standardized analytical workflows, validate findings in large prospective multicentric studies, and integrate uEV-based assays into precision medicine approaches.