The Angiogenic and Adipogenic Modes of Adipose Tissue after Free Fat Grafting

Abstract

The angiogenesis of the graft occurs by the classic "vessel branching" mode, in which the recipient plays a dominant role. The mode of graft tissue retention primarily involves CD34 adipose precursor cells derived from the recipient.

In vivo tissue engineering of an adipose tissue flap using fat grafts and Adipogel

“…Recent studies by other groups provide strong support for the hypothesis that when fat grafting is successful, this is explained by graft remodelling by stem cells rather than by adipocyte survival (Doi et al, 2015;Dong et al, 2015;Eto et al, 2012;Kato et al, 2014;Zhang et al, 2018). Furthermore, we have reported that the vast majority of grafted adipocytes dies when human fat grafts are implanted in a flow-through chamber model or subcutaneously in the scalp (Tang et al, 2018) in mice and yet new fat growth was seen in each case that was largely host derived.…”

Do Stem Cells Have an Effect When We Fat Graft?

“…More recent models suggest that recipient adipocytes may be more significant in replacing the necrotic adipocytes. 28 A study using green fluorescent protein mice reveal that regenerated adipocytes mostly originate from ASCs within the grafted tissue, although only ASCs located adjacent to the necrotic adipocytes differentiated directly into adipocytes. 29 In contrast, a recent transcriptional analysis of ASCs within grafted fat transplants demonstrated no changes in adipogenic differentiation, challenging the belief that ASCs contribute to regenerating adipocytes.…”

“…31 Studies of transgenic mice demonstrate that the neovasculature of fat grafts is derived from the recipient animal, refuting the direct contribution of ASCs in revascularization. 28 The current predominant hypothesis is that ASCs promote revascularization of ischemic free fat grafts through the release of proangiogenic paracrine growth factors, including vascular endothelial growth factor (VEGF), basic fibroblast growth factor, hepatocyte growth factor, and insulinlike growth factor-1. 32,33 Lipoaspirate supplemented with ASCs has been shown to improve angiogenesis and long-term graft retention through the release of these factors.…”

Enrichment of Adipose-Derived Stromal Cells for BMPR1A Facilitates Enhanced Adipogenesis

“…30 As a large proportion of the original adipocytes within a fat graft ultimately die, their replacement is dependent on the adipogenic differentiation of ASCs found locally within the graft or which have been recruited from the surrounding recipient site. [31][32][33] Furthermore, in settings requiring small volume fat transfer, such as during craniofacial reconstruction, an alternative strategy would be to transplant specialized ASC subpopulations capable of de novo adipogenesis into existing fat depots.…”