Background: Clinical results of fat grafting have been unpredictable. In this article, the authors hypothesize that centrifugation creates “graded densities” of fat with varying characteristics that influence lipoaspirate persistence and quality.
Methods: Aliquots of human female lipoaspirate (10 cc) were centrifuged for 3 minutes at 1200 g. The bloody and oil fractions were discarded. Subsequently, 1.0 cc of the highest density and lowest density fat was separated for lipoinfiltration or analysis. Highest density or lowest density fat grafted into adult FVB mice was harvested at 2 and 10 weeks to quantify short- and long-term persistence, respectively. Progenitor cell number and expression of vascular endothelial growth factor, stromal cell–derived factor-1α, platelet-derived growth factor, and adiponectin were analyzed by flow cytometry and enzyme-linked immunosorbent assay, respectively.
Results: Greater percentages of highest density fat grafts remain at 2 and 10 weeks after injection compared with lowest density fat grafts (85.4 ± 1.9 percent versus 62.3 ± 0.1 percent, p = 0.05; and 60.8 ± 4.9 versus 42.2 ± 3.9, p < 0.05, respectively). Highest density fractions contain more progenitor cells per gram than lowest density fractions (2.0 ± 0.2-fold increase, p < 0.01). Furthermore, concentrations of vascular endothelial growth factor, stromal vascular fraction, platelet-derived growth factor, and adiponectin are all elevated in highest density compared with lowest density fractions (34.4 percent, p < 0.01; 34.6 percent, p < 0.05; 52.2 percent, p < 0.01; and 45.7 percent, p < 0.05, respectively).
Conclusions: Greater percentages of highest density fractions of lipoaspirate persist over time compared with lowest density fractions. A vasculogenic mechanism appears to contribute significantly, as highest density fractions contain more progenitor cells and increased concentrations of several vasculogenic mediators than lowest density fractions.
New York, N.Y.
From the Institute of Reconstructive Plastic Surgery Laboratories, New York University Langone Medical Center.
Received for publication February 26, 2012; accepted July 2, 2012.
Presented in part at the International Federation of Adipose Therapeutics and Science Conference, in Toulouse, France, October 24 through 26, 2008, and Plastic Surgery 2009: American Society of Plastic Surgeons Annual Meeting, in Seattle, Washington, October 23 through 27, 2009.
Disclosure: Dr. Coleman receives royalties from instruments produced by Mentor and is a paid advisor for Mentor. The other authors have no financial interest to declare.
This work was supported by THE PLASTIC SURGERY FOUNDATION.
Alexes Hazen, M.D.; Institute of Reconstructive Plastic Surgery, New York University Langone Medical Center, 560 First Avenue, TCH-169, New York, N.Y. 10016, firstname.lastname@example.org