Pluronic F-127 Hydrogel Loaded with Human Adipose-Derived Stem Cell-Derived Exosomes Improve Fat Graft Survival via HIF-1α-Mediated Enhancement of Angiogenesis.

Purpose: Autologous fat grafting is playing an increasingly important role in plastic surgery. However, high absorption and low survival of autologous fat grafts limit their clinical application. This study aimed to investigate whether human adipose-derived stem cell-derived exosomes (hASC-Exos) encapsulated in a PF-127 hydrogel can improve the survival of autologous fat grafts and to elucidate the underlying mechanisms. Patients and Methods: Exosomes were isolated from hASCs and identified using transmission electron microscopy, nanoparticle tracking analysis and Western blotting. We performed functional assays in vitro to assess the effect of hASC-Exos on proliferation, migration, and tube formation as well as their regulatory role in the HIF-1α/VEGF signaling pathway. hASC-Exos encapsulated in the PF-127 hydrogel were used as an in vivo autologous fat graft model. The effects of the PF-127 hydrogel/hASC-Exos and the role of the HIF-1α/VEGF signaling pathway in promoting angiogenesis in an autologous fat grafting model were assessed. Results: hASC-Exos were taken up by human umbilical vein endothelial cells and enhanced their proliferation, migration, and tubule formation in vitro. The effects of hASC-Exos on promoting angiogenesis were mediated by the HIF-1α/VEGF signaling pathway. Moreover, we fabricated a PF-127 hydrogel for the sustained release of hASC-Exos, and in vivo results showed that hASC-Exos encapsulated in PF-127 hydrogel improved the survival of autologous fat grafts. Conclusion: Our findings indicated that hASC-Exos encapsulated in PF-127 hydrogel serve as a key regulator of angiogenesis by activating the HIF-1α/VEGF signaling pathway and provide a promising strategy for autologous fat grafting treatment.