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

Background: Cell-assisted lipotransfer (CAL) is a process in which fat grafting is supplemented with autologous adipose-derived stromal cells (ASCs). Since the efficacy of the technique was demonstrated, studies have focused on the mechanism by which CAL enhances the rate of graft survival. However, the microenvironmental changes in donor and recipient tissue associated with CAL remain unclear. Methods: We introduced an animal model of CAL using two different transgenic reporter mice. Donor fat from GFP-expressing C57BL/6J mice and donor ASCs from DsRed-expressing C57BL/6J mice were co-transplanted into recipient C57BL/6J mice. During adipose remodeling after CAL, the fate of each donor adipocyte and donor ASC was traced using immunofluorescent staining with the whole-mount method. Results: ASC supplementation altered inflammation and promoted angiogenesis and subsequent revascularization in recipient tissue. Tracing at postoperative week 4 revealed that survived donor ASCs participated in angiogenesis by differentiating into endothelial cells. Moreover, newly differentiated fat from donor ASCs and recipient tissue integrated with survived donor fat, leading to improved retention of the graft. ASC supplementation resulted in a quantitative difference in angiogenesis and adipogenesis during adipose remodeling according to the concentration of ASCs. Conclusions: We characterized the dynamic changes occurring in donor ASCs and fat as well as recipient tissue by tracing these cellular components following CAL. Our findings highlight the therapeutic value of CAL in tissue transplantation. (C)2017American Society of Plastic Surgeons