Nonhealing wounds remain a significant challenge for plastic surgeons. More than 600,000 people suffer from venous ulcers and 1.5 to 3 million people are being treated for pressure sores every year in the United States. The use of tissue engineering techniques such as stem-cell therapy and gene therapy to improve wound healing is a promising strategy. Adipose tissue represents a source of cells that may be able to enhance wound healing. Adipose-derived stem cells (ASCs) are adult stem cells that are easily harvested and of great interest for plastic surgeons. Specifically, ASCs secrete angiogenic growth factors that can induce tissue regeneration. This review describes innovative research strategies using ASCs therapies for treatment of chronic, nonhealing wounds.

Background Fat grafting is a promising technique for soft-tissue augmentation, although graft retention is highly unpredictable and factors that affect graft survival have not been well defined. Because of their capacity for differentiation and growth factor release, adipose-derived stem cells may have a key role in graft healing. The authors’ objective was to determine whether biological properties of adipose-derived stem cells present within human fat would correlate with in vivo outcomes of graft volume retention. Methods Lipoaspirate from eight human subjects was processed using a standardized centrifugation technique and then injected subcutaneously into the flanks of 6-week-old athymic nude mice. Graft masses and volumes were measured, and histologic evaluation, including CD31+ staining for vessels, was performed 8 weeks after transplantation. Stromal vascular fraction isolated at the time of harvest from each subject was analyzed for surface markers by multi-parameter flow cytometry, and also assessed for proliferation, differentiation capacity, and normoxic/hypoxic vascular endothelial growth factor secretion. Results Wide variation in percentage of CD34+ progenitors within the stromal vascular fraction was noted among subjects and averaged 21.3 ± 15 percent (mean ± SD). Proliferation rates and adipogenic potential among stromal vascular fraction cells demonstrated moderate interpatient variability. In mouse xenograft studies, retention volumes ranged from approximately 36 to 68 percent after 8 weeks, with an overall average of 52 ± 11 percent. A strong correlation (r = 0.78, slope = 0.76, p < 0.05) existed between stromal vascular fraction percentage of CD34+ progenitors and high graft retention. Conclusion Inherent biological differences in adipose tissue exist between patients. In particular, concentration of CD34+ progenitor cells within the stromal vascular fraction may be one of the factors used to predict human fat graft retention. (Plast. Reconstr. Surg. 132: 845, 2013.)