The Influences of the Density of ASCs and the Stromal Condensation Rates (SCR) on Volume Maintenance Rates (VMR) in the Fresh Fat Graft

Abstract

We have been working on the mechanism of the volume maintenance of the fat graft. We regarded the volume maintenance rate as reversely proportional to absorption rates. The main portion of the absorbed volume would be regarded as lipid components. So, we focused on the proportion of lipid as a reason of complications like high absorption or oil cysts. Lipid droplets within cell membranes rarely make problem, but right after the breakage of cell membrane, oil would be released into stromal space. We compared the volume maintenance rates and histological findings in six experimental groups categorized by different processing methods which give different kinds of mechanical stresses to the lipoaspirates like centrifugation force, pressure gradients and mechanical friction. We hypothesize these stresses would increase gross oil removal rates and stromal condensation rates which reflect ASCs density (stromal cell numbers/unit volume) within whole tissues. As a result, a certain amount of mechanical stress to fat tissues before the injection increases not only the stromal condensation rates (SCR), but also the volume maintenance rates (VMR) at the same time in a fresh human fat graft to nude mice. As a conclusion, the stromal condensation with squeezing (1) increased the density of ASCs and (2) decreased the number of fully matured, relatively older adipocytes which reflect the total amount of free oil within the graft materials. These two conditions are accompanied by simultaneously increased volume maintenance rates (VMR) of the fat graft.