Research of the Fate of Fat Graft

 

Purpose:

Clinical outcomes following fat grafting are variable and technique dependent, and it is unknown how the graft survived. 2 theories had been purposed: Cell survival theory and Host replacement theory. Previous studies^1-3 supported either theory, but the mechanism of fat graft survival is still unclear. Therefore, we try to investigate the fate of fat graft and the role of adipose derived stem cell (ASC).

Materials and Methods:

Adipose tissue from 3 healthy volunteers was harvested with the traditional liposuction method. These were grafted on 12 nude mice with or without the isolated and cultured ASCs (each group n=6), after which specimens were evaluated on day 1, 4, 7, 14, 28, 90 using hematoxylin-eosin (H&E), anti-perilipin antibody and anti-MHC class I labeling. Vascularity was evaluated with anti-mouse CD31 antibody. Protein analysis for vascular endothelial growth factor (VEGF) was performed by Enzyme-Linked Immunosorbent Assay (ELISA).

Results:

Comparing with control group, the ASC group had more retaining weight and less fibrosis at day 90. At early stage of grafting (day 7 and 14), ASC group had higher vascular density and VEGF. At day 90, only part of human adipocytes (about 25%) survived but there is no significant difference in the amount of human adipocytes between ASC group and control group. In other words, the ASCs recruit more host cells in the scaffold of the grafted fat.

Conclusion:

The fate of fat graft should be based on both cell survival theory and host replacement theory, and ASCs recruit more host cells to enhance fat graft maintenance.