Beyond the cells: scaffold matrix character affects the in vivo performance of purified adipocyte fat grafts.

BACKGROUND Little attention has been focused on the effect of fat graft structure on in vivo performance. Having hypothesized that a stable initial graft structure was important to fat graft take-similar to the importance of shear minimization in the take of skin grafts-we have previously shown that purified adipocytes suspended in a resorbable protein matrix (GFR Matrigel; BD Biosciences, San Jose, CA) improved in vivo graft longevity. OBJECTIVE In the present study, the importance of the matrix composition was assessed. METHODS Age- and sex-matched genetically identical mice were implanted with fat grafts consisting of the same number of purified adult adipocytes mixed with either PuraMatrix (simple peptide hydrogel; 3DM, Cambridge, MA) or GFR Matrigel (basement membrane proteins). Control grafts composed of GFR Matrigel alone, PuraMatrix alone, or syringe-harvested (unpurified) fat alone were also injected. Volume measurements and histologic sections were taken at 1 week, 1 month, and 3 months. RESULTS Purified fat/GFR Matrigel grafts showed statistically greater longevity and volume maintenance versus all other groups. CONCLUSIONS Differences in matrix composition in this study were associated with profound changes in graft longevity and volume maintenance. These results suggest that cell-extracellular matrix interactions play an important role in graft survival. Future research into the nature of these interactions may provide an avenue for optimizing fat graft outcomes.