Development of a 3D <i>in Vitro</i> Wound Healing Model to Assess the Effect of ADSC-EVs on Vascularization

Angiogenesis is critical for effective wound healing and relies on the successful coordination of various cell types, including endothelial cells, macrophages, and fibroblasts. Adipose-derived stem cell extracellular vesicles (ADSC-EVs) have demonstrated proangiogenic properties and have been posited as a novel therapeutic to aid wound healing; however, their functional impact within human-derived multicellular models remains largely uncharacterized. This study explores the development and application of a 3D multicellular <i>in vitro</i> model to assess the effects of ADSC-EVs on vascularization in the context of wound healing. 3D multicellular <i>in vitro</i> models were developed by coculturing human umbilical vein endothelial cells (HUVECs), monocyte-derived macrophages, and fibroblasts within Matrigel to recapitulate the <i>in vivo</i> wound healing microenvironment. A five-color confocal microscopy panel was developed to visualize each cell type and EVs within the models. The optimized models were then treated with ADSC-EVs or control to determine their impact on angiogenesis and cell colocalization. We determined that vessel formation was significantly enhanced when HUVECs were cocultured in multicellular models compared with monocultures, with the greatest effect observed in the full three-cell-type model. This effect was even more pronounced with the addition of ADSC-EVs. ADSC-EV treatment also enhanced macrophage colocalization within endothelial structures. This study developed a multicellular model that can be used for future work assessing wound healing <i>in vitro</i> and will be additive to currently used single-cell and <i>in vivo</i> models. We have applied these models to demonstrate that ADSC-EVs significantly enhance tube formation in HUVECs and the development of tissue-like structures in multicell systems, highlighting their potential as a promising therapeutic approach for improving wound healing.