Extracellular Vesicles from Human Umbilical Cord Mesenchymal Stem Cells Facilitate Diabetic Wound Healing Through MiR-17-5p-mediated Enhancement of Angiogenesis.

Endothelial dysfunction caused by persistent hyperglycemia in diabetes is responsible for impaired angiogenesis in diabetic wounds. Extracellular vehicles (EVs) are considered potential therapeutic tools to promote diabetic wound healing. The aim of this study was to investigate the effects of EVs secreted by human umbilical cord mesenchymal stem cells (hucMSC-EVs) on angiogenesis under high glucose (HG) conditions in vivo and in vitro and to explore the underlying mechanisms. In vivo, local application of hucMSC-EVs enhanced wound healing and angiogenesis. In vitro, hucMSC-EVs promoted proliferation, migration, and tube formation by inhibiting phosphatase and tensin homolog (PTEN) expression and activating the AKT/HIF-1α/VEGF pathways. MiR-17-5p was found to be highly enriched in hucMSC-EVs. In vitro, MiR-17-5p agomirs downregulated the expression of PTEN and activated the AKT/HIF-1α/VEGF pathway to promote proliferation, migration, and tube formation in HG-treated HUVECs. In vivo, miR-17-5p agomirs mimicked the effects of hucMSC-EVs on wound healing and angiogenesis, whereas miR-17-5p inhibitors reversed their effects. Our findings suggest that hucMSC-EVs have regenerative and protective effects on HG-induced endothelial cells via transfer of miR-17-5p targeting PTEN/ AKT/HIF-1α/VEGF pathway, thereby accelerating diabetic wound healing. Thus, hucMSC-EVs may be promising therapeutic candidates for improving diabetic wound angiogenesis.