Improving Fat Grafting Outcome through Enhanced Vasculogenesis: Cell-enriched Fat Grafting with Quality and Quantity cultured Endothelial Progenitor Cells

Fat grafting has become common practice for soft tissue reconstruction. Its main limitation remains ischemia with subsequent tissue loss, patient dissatisfaction and the need for additional surgical procedures. Mononuclear cells (MNCs) in the peripheral blood contain a low percentage of endothelial progenitor cells (EPCs), and often these EPCs have an impaired function in human subjects. The Quality and Quantity culture (QQ) has been developed to phenotypically transform MNCs into a highly vasculogenic cell population for therapeutic vasculogenesis. We hypothesized that enrichment of fat grafts with QQ-cultured EPCs leads to the development of a dense vascular network in the fat graft, contributing to an increased graft retention and better tissue quality. In two experimental studies, this hypothesis was tested. Firstly, QQ-cultured KSL-cells, as a murine source of EPCs, were added to murine adipose tissue, and grafted in recipient mice. Secondly, QQ-cultured human MNCs were added to lipoaspirates, and grafted in nude recipient mice. After in vitro confirmation of the vasculogenic potential of the QQ-cultured cells, we demonstrated the in vivo contribution of the QQ-cultured cells to the vascularization. The QQ-cultured KSL-cells increased the vessel density in murine fat grafts, and decreased fibrosis. The QQ-cultured MNCs also stimulated the fat graft to develop a rich vessel network, with EPCs integrating in vessel walls, and mitigated the graft’s resorption.