Umbilical cord blood–derived extracellular vesicles improve erectile function in diabetic mice via PI3K-Akt-E2F–mediated neurovascular regeneration

Background Erectile dysfunction (ED) is a common, debilitating complication of diabetes mellitus, driven by endothelial dysfunction, neurovascular injury, and oxidative stress. Although mesenchymal stem cells confer benefit, concerns regarding safety, scalability, and standardization have shifted interest to cell-free therapies. Umbilical cord blood–derived extracellular vesicles (UCB-EVs) are protein-rich with regenerative potential, but their efficacy in diabetic ED remains unknown. Methods We isolated and characterized UCB-EVs and evaluated them across in vitro, ex vivo, and in vivo platforms: human umbilical vein and mouse cavernous endothelial cells under high glucose; aortic ring, dorsal root ganglion, and major pelvic ganglion explants; and streptozotocin-induced diabetic mice. Erectile function was quantified by intracavernous pressure after intracavernous UCB-EV delivery (5–20 µg). Mechanistic assays included immunofluorescence, terminal deoxynucleotidyl transferase dUTP nick end labeling, phospho-histone H3, reactive oxygen species staining, western blotting, RNA sequencing, and gene set enrichment analysis. Results UCB-EVs enhanced tube formation, migration, and microvessel sprouting under high glucose and promoted neurofilament-positive neurite extension in dorsal root ganglion and major pelvic ganglion explants. In diabetic mice, UCB-EV treatment improved ~ 90% of control intracavernous pressure, preserved PECAM-1–positive endothelial cells and NG2–positive pericytes, and increased neuronal markers—neurofilament and neuronal nitric oxide synthase (nNOS). Mechanistically, UCB-EVs reduced apoptosis and oxidative stress, increased endothelial proliferation, and activated PI3K (phosphoinositide 3-kinase)–Akt signaling. Transcriptomics showed reversal of diabetes-associated programs, enrichment of angiogenic and neurogenic networks, and significant upregulation of the Hallmark E2F Targets gene set, consistent with improved cell-cycle progression and reparative proliferation. Conclusions UCB-EVs promote neurovascular repair and functional recovery in diabetic ED by coordinating angiogenesis, neurogenesis, anti-apoptotic signaling, and PI3K–Akt–E2F pathway activation. These findings support UCB-EVs as a promising, safe, and scalable cell-free therapeutic candidate for diabetic ED and justify further studies to define active mediators, durability, and efficacy across diabetic models.