From Mesenchymal Roots to Pluripotent Reprogramming: Exosomal Crossroads in Regenerative Medicine.

Despite growing interest in exosome-based regenerative therapies, conventional mesenchymal stem cell (MSC) and somatic cell derived exosomes face persistent translational barriers, including donor heterogeneity, ethical constraints, limited scalability, and batch-to-batch variability. It remains unclear how far induced pluripotent stem cell (iPSC) derived exosomes can address these limitations, and how their advantages and remaining translational barriers compare with those of established MSC exosome platforms. This review synthesizes current evidence on the biology, therapeutic applications, and bioengineering of exosomes across cellular sources, with a focus on critically comparing MSC- and iPSC-derived exosomes rather than cataloguing individual sources in isolation. iPSC-derived exosomes are, on the evidence reviewed here, the more promising long-term platform; their unlimited, genetically homogeneous, and engineerable source material addresses the donor heterogeneity, ethical, and scalability limits that constrain MSC exosomes at their root, rather than merely working around them. This advantage remains largely theoretical in practice, however, since iPSC exosome production, GMP manufacturing, and clinical validation currently lag behind the more established MSC exosome pipeline. Closing that gap, rather than the underlying biological case for iPSCs, is therefore the critical bottleneck this review identifies. The first registered human trials of iPSC derived exosomes have now appeared, in stable vitiligo, atopic dermatitis, and Moyamoya disease, but these small, early phase, and dermatology or topical delivery led, underscoring that closing translational gaps, GMP compliant and AI assisted manufacturing, standardized potency and safety assays, exosome specific rather than cell inherited genomic risk assessment, and clearr regulatory pathways will determine whether either platform, or a combination of both, moves from this narrow clinical foothold to routine use.