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.