Degeneration, Regeneration, and Cicatrization after Fat Grafting

Abstract

Dynamic remodeling after fat grafting was confirmed. Adipocyte fate differed, depending on the microenvironment: intact survival, replacement with a new adipocyte, or replacement with cicatrization/oil cyst. This detailed understanding will help refine surgical grafting procedures and postoperative evaluation.

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.…”

“…It is becoming increasingly clear from a number of recent studies that if there is adipocyte survival in grafted fat, this is restricted to the very outermost (100-300 μm) layer (Doi et al, 2015;Dong et al, 2015;Eto et al, 2012;Kato et al, 2014;Tang et al, 2018;Zhang et al, 2018), termed the "survival zone" (Eto et al, 2012). We were unable to identify such a zone in our constructs, and indeed, both adipocytes and adipose-derived stem cells (ASCs; discussed below) throughout the graft showed very poor survival.…”

“…Adipogel could not be demonstrated to improve adipocyte survival in Group 2 compared with Group 1 (fat alone), although surgical complications leading to n = 2 only for the latter at 6 weeks made a strong comparison difficult (p = .11, one-way analysis of variance). That the bulk of graft adipocytes die is not surprising and has been demonstrated in numerous recent experimental studies (Doi et al, 2015;Dong et al, 2015;Eto et al, 2012;Kato et al, 2014;Stillaert et al, 2007;Tang et al, 2018;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. We (Tang et al, 2018) and others (Kato et al, 2014) have also suggested that after such adipocyte death, these dead cells, along with their lipid content and surrounding extracellular matrix, still likely play a positive role in maintaining graft volume during the subsequent regenerative process.…”

Human Breast Adipose-Derived Stem Cells Transfected with the Stromal Cell-Derived Factor-1 Receptor CXCR4 Exhibit Enhanced Viability in Human Autologous Free Fat Grafts

“…This delay appears to critically impair the survival of the fat cells, which undergo degenerative changes, including the destruction of their nucleus and cell membranes. After this cell destruction, fatty cysts develop and the fat gradually becomes absorbed [25]. Thus, early and abundant neovasculization seems to be the key to the survival of free fat transplants, which in turn leads to good transplant outcomes.…”