Enhancement of Progenitor Cells by Two-Step Centrifugation of Emulsified Lipoaspirates.

BACKGROUND: Adipose-derived stem cells, endothelial progenitor cells, and soluble factors jointly contribute to the regenerative effect of fat grafts. Nanofat grafting emulsifies the lipoaspirate and increases the progenitor cell yield. In the present study, the authors evaluated their extended nanofat grafting method that includes two additional centrifugation steps and results in a lipoaspirate of low volume that they termed "lipoconcentrate." Furthermore, the authors investigated the oily fractions after centrifugation for their regenerative potential. METHODS: Lipoaspirates of 20 healthy patients were processed by emulsification and/or centrifugation. Six groups were created: native (not emulsified) fat, 1× centrifuged native fat, 2× centrifuged native fat, nanofat (emulsified), 1× centrifuged nanofat, and lipoconcentrate (i.e., 2× centrifuged nanofat). The oily phases after the centrifugation steps were collected. Progenitor cells and basic fibroblast growth factor, insulin-like growth factor 1, matrix metalloproteinase-9, platelet-derived growth factor-BB, and vascular endothelial growth factor-A levels were measured by flow cytometry and immunoassays. RESULTS: Lipoconcentrate contained significantly higher numbers of adipose-derived stem cells and endothelial progenitor cells per gram compared with all other fractions. No difference of all five soluble factors between groups was found. The oily phases after centrifugation showed no or very few adipose-derived stem cells and endothelial progenitor cells, and no or very low levels of soluble factors. CONCLUSIONS: Centrifugation of emulsified lipoaspirates increases the progenitor cell count in the lipoaspirate. The oily phase after centrifugation of lipoaspirates may be disposable because of the minuscule content of progenitor cells and soluble factors.

Content of Soluble Factors and Characteristics of Stromal Vascular Fraction Cells in Lipoaspirates from Different Subcutaneous Adipose Tissue Depots.

BACKGROUND: Although fat grafting has emerged as a major force in plastic, reconstructive, and aesthetic surgery, some questions regarding its reliability and regenerative potential remain unanswered. OBJECTIVES: The authors examined the influence of three anatomic areas on various lipoaspirate properties to identify the most appropriate harvest site for fat-grafting procedures. METHODS: Lipoaspirates from 25 healthy patients were harvested from the abdomen, inner thigh, and knee. The authors measured the content of soluble factors in the lipoaspirate followed by the assessment of the yield, adipogenic differentiation, proliferation of stromal vascular fraction (SVF) cells, and the percentage of adipose-derived stem cells (ASC) in the SVF. The results also were correlated with the age and body mass index of the donors. RESULTS: Lipoaspirates from the abdomen showed significantly higher concentrations of matrix metalloproteinase (MMP)-9 compared with the knee. The content of basic fibroblast growth factor (b-FGF), platelet-derived growth factor (PDGF)-BB, and insulin-like growth factor (IGF)-1 tended to be highest in the abdomen but did not reach statistical significance. Vascular endothelial growth factor (VEGF)-A and bFGF-2 contents both correlated negatively with age in lipoaspirates from at least two different anatomic areas. CONCLUSIONS: The authors' results indicate that the abdomen may be a slight favorite over the inner thigh and knee because of its richer content of soluble factors. However, because only the difference of MMP-9 content actually reached statistical significance and because no differences in SVF characteristics were observed, a decision primarily based on other criteria appears to be justifiable.