E. R. Zielins1, K. Paik1, D. A. Atashroo1, Z. N. Maan1, A. Luan1, S. M. Vistnes1, G. Walmsley1, K. Senarath-Yapa1, R. Tevlin1, T. Wearda1, O. Marecic1, M. T. Longaker1, D. C. Wan1 1Stanford University,Division Of Plastic And Reconstructive Surgery,Palo Alto, CA, USA
Introduction:
Known as cell-assisted lipotransfer (CAL), the addition of autologous adipose derived stem cells (ASCs) has shown much promise as a technique to improve fat graft take. As the number of ASCs required for optimum fat graft retention remains unknown, we have attempted to determine this using a murine model of fat grafting.
Methods:
Human fat was mixed with ASCs obtained from patient-matched lipoaspirate and injected into the subcutaneous plane of the scalps of athymic nude mice. The number of ASCs injected per 200μL fat graft ranged from 10,000 to 10 million. Fat graft volume retention was assessed via CT scanning at 8 weeks, with explanted grafts compared histologically for overall architecture and vascularity.
Results:
Maximum fat graft retention was seen with the addition of 10,000 ASCs, with volumes significantly larger (*p<0.05) than those of unsupplemented grafts. The addition of higher number of cells negatively impacted fat graft retention, with supplementation with 10 million ASCs producing the lowest final volumes. Overall fat graft architecture and was not affected by supplementation with ASCs, though fat grafts supplemented with 10,000 ASCs showed increased vascularity.
Conclusion:
Our study has shown that there is in fact dose dependence in the number of ASCs that can be added to a fat graft. While known for their pro-adipogenic and pro-angiogenic effects, it would seem that the ability of ASCs to enhance fat grafting must be counterbalanced by their potential to outcompete resident adipocytes and stromal cells for nutrients during the post-graft period.