Urine-Derived Stem Cells: Challenges in Isolation, Biological Identity, and Therapeutic Potential in CKD-Associated Fibrosis
Urine-derived stem cells (UDSCs) have emerged as a promising cell source for regenerative medicine due to their non-invasive procurement, high proliferative capacity, and potential relevance to kidney-specific repair. Unlike conventional mesenchymal stem cells (MSCs) obtained from bone marrow or adipose tissue, UDSCs originate from multiple regions of the urinary tract and exhibit a unique biological profile that combines MSC characteristics with features of renal progenitor populations. This review provides a comprehensive overview of the current understanding of UDSC biology, including their origin, isolation strategies, morphology, immunophenotypic characteristics, differentiation potential, and secretory profile. Particular attention is given to the expression of renal lineage-associated markers and pluripotency-related factors that may contribute to their regenerative capacity. The bioactive mediators of UDSCs regulate inflammation, oxidative stress, angiogenesis, and extracellular matrix remodeling, thereby influencing key pathways implicated in chronic kidney disease (CKD)-associated fibrosis. Furthermore, the intrinsic renal progenitor signature of UDSCs may provide advantages in renal homing and tissue-specific repair compared with conventional MSC populations. Despite encouraging preclinical findings, significant challenges remain, including cellular heterogeneity, inconsistent isolation efficiency, lack of standardized characterization criteria, and limited clinical validation. Collectively, current evidence positions UDSCs as a biologically distinct and therapeutically attractive platform for kidney regeneration.