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.