Small extracellular vesicles from deferoxamine-primed stem cells promote angiogenesis and tissue integration

Aim: We investigated whether the secretome, particularly small extracellular vesicles (sEVs), obtained from deferoxamine (DFO)-pretreated stem cells from human exfoliated deciduous teeth (SHED), could promote angiogenesis in human umbilical vein endothelial cells (HUVECs) and support vascularized tissue integration under preliminary ectopic implantation conditions. Methods: SHED were treated with DFO (2.5, 5, 10 μM), and RNA sequencing was performed to analyze gene expression changes in DFO-treated SHED. The effects of the DFO-pretreated SHED secretome and the isolated sEVs (DFO-sEVs) on HUVEC migration were evaluated. The angiogenic capacity was assessed using wound healing, Transwell migration, and tube formation assays. DFO-sEVs were also tested for their ability to regulate macrophage polarization using immunofluorescence staining. Finally, DFO-sEVs were encapsulated in hydrogels and subcutaneously implanted into Sprague-Dawley rats, and their pro-angiogenic capacity in vivo was assessed via histological staining. Results: RNA-seq analysis indicated that DFO pretreatment modulated SHED pathways related to hypoxia response, cell adhesion, and inflammation. The secretome from SHED pretreated with 5 μM DFO significantly promoted HUVEC migration and tube formation. DFO-sEVs, particularly from the 5 μM DFO group, demonstrated superior pro-angiogenic effects compared to sEVs from untreated SHED both in vitro and in vivo. Furthermore, DFO-sEVs drove macrophages to adopt an M2-like reparative polarization. Conclusion: DFO pretreatment functionally potentiates the pro-angiogenic and immunomodulatory properties of SHED-derived sEVs. The findings suggest that DFO-sEVs may provide a bioactive component for promoting angiogenesis and facilitating tissue integration.