Microvascular angiogenesis and apoptosis in the survival of free fat grafts.
OBJECTIVE
Autologous fat is an ideal material for augmentation in plastic surgery because of its minimal tissue reaction and easy availability, but its long-term graft survival is somewhat unpredictable. This study was conducted to determine how fat grafts get their vascular supply from the recipient bed and why they keep reducing in volume and weight.


METHODS
Experimental study using animal models.


METHODS
The expression of vascular endothelial growth factor (VEGF) in grafted fat tissue was examined by using immunohistochemical staining, and apoptotic cell death in the grafted fat was studied by using terminal deoxynucleotidyl transferase (TdT)-mediated deoxy-uridine triphosphate (dUTP)-biotin nick end-labeling method. Twenty-five Wistar rats were used as models of free fat grafts. Fat tissue taken from inguinal fat pads was grafted to the back skin with an 18-gauge needle injection.


RESULTS
The weight of the injected fat was significantly reduced on the 180th day compared with the original weight (32% +/- 10%). VEGF+ cells were observed in fibrous connective tissue of the grafts on days 7 and 30 but not after day 90. Apoptotic cells were also observed on days 7 and 30.


CONCLUSIONS
Angiogenic factors including VEGF started to revascularize the graft around day 7, and the extent of the vasculature was not reduced after the revascularization. In addition to necrosis in the graft's early stages, apoptosis induced by many factors in the graft's environment is also, at least in part, a cause of long-term volume reduction of the fat graft. Thus clinical application of angiogenic factors such as VEGF to fat grafts and control of apoptosis may contribute to improvements in fat-grafting techniques.
Nishimura
T
T
Department of Otolaryngology--Head and Neck Surgery, Kanazawa University School of Medicine, Japan.
Hashimoto
H
H
Nakanishi
I
I
Furukawa
M
M
D000273:Adipose Tissue / Q000637:transplantation*; D000818:Animals; D017209:Apoptosis; D016228:Endothelial Growth Factors / Q000378:metabolism*; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008222:Lymphokines / Q000378:metabolism*; D018919:Neovascularization, Physiologic; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors