The fate of the adipose-derived stromal cells during angiogenesis and adipogenesis after cell-assisted lipotransfer

Background: Cell-assisted lipotransfer is a process in which fat grafting is supplemented with autologous adipose-derived stromal cells. Since the efficacy of the technique was demonstrated, studies have focused on the mechanism by which cell-assisted lipotransfer enhances the rate of graft survival. However, the microenvironmental changes in donor and recipient tissue associated with cell-assisted lipotransfer remain unclear. Methods: The authors introduced an animal model of cell-assisted lipotransfer using two different transgenic reporter mice. Donor fat from green fluorescent protein–expressing C57BL/6J mice and donor adipose-derived stromal cells from DsRed-expressing C57BL/6J mice were co-transplanted into recipient C57BL/6J mice. During adipose remodeling after cell-assisted lipotransfer, the fate of each donor adipocyte and donor adipose-derived stromal cell was traced using immunofluorescent staining with the whole-mount method. Results: Adipose-derived stromal cell supplementation altered inflammation and promoted angiogenesis and subsequent revascularization in recipient tissue. Tracing at postoperative week 4 revealed that surviving donor adipose-derived stromal cells participated in angiogenesis by differentiating into endothelial cells. Moreover, newly differentiated fat from donor adipose-derived stromal cells and recipient tissue integrated with surviving donor fat, leading to improved retention of the graft. Adipose-derived stromal cell supplementation resulted in a quantitative difference in angiogenesis and adipogenesis during adipose remodeling according to the concentration of adipose-derived stromal cells. Conclusions: The authors characterized the dynamic changes occurring in donor adipose-derived stromal cells and fat and recipient tissue by tracing these cellular components following cell-assisted lipotransfer. The authors’ findings highlight the therapeutic value of cell-assisted lipotransfer in tissue transplantation.