Studies in Fat Grafting: Part IV. Adipose-derived stromal cell gene expression in cell-assisted lipotransfer
Garza, R.M., Rennert, R.C., Paik, K.J., et al.
Fat graft volume retention remains highly unpredictable, but addition of adipose-derived stromal cells (ASCs) to fat grafts has been shown to improve retention. The present study aimed to investigate the mechanisms involved in ASC enhancement of fat grafting.
ASCs isolated from human lipoaspirate were labeled with green fluorescent protein (GFP) and luciferase. Fat grafts enhanced with ASCs were injected into the scalp and bioluminescent imaging was performed to follow retention of ASCs within the fat graft. Fat grafts were also explanted at days 1, 5, and 10 post-grafting for ASC extraction and single-cell gene analysis. Finally, CD31 immunohistochemical staining was performed on fat grafts enriched with ASCs.
Bioluminescent imaging demonstrated significant reduction in luciferase+ ASCs within fat grafts at five days post-grafting. A similar reduction in viable GFP+ ASCs retrieved from explanted grafts was also noted. Single cell analysis revealed expression of multiple genes/markers related to cell survival and angiogenesis including BMPR2, CD90, CD105, FGF2, CD248, TGFβ1, and VEGFA. Genes involved in adipogenesis were not expressed by ASCs. Finally, CD31 staining revealed significantly higher vascular density in fat grafts explanted at day 10 post-grafting.
Although ASC survival in the hypoxic graft environment decreases significantly over time, these cells provide multiple angiogenic growth factors. Therefore, improved fat graft volume retention with ASC enrichment may be due to improved graft vascularization.
Garza, R.M., Rennert, R.C., Paik, K.J., et al. "Studies in Fat Grafting: Part IV. Adipose-derived stromal cell gene expression in cell-assisted lipotransfer" Plastic and Resconstructive Surgery (2015): 1,045–55