Comparison of Harvest and Processing Techniques for Fat Grafting and Adipose Stem Cell Isolation

Background: Variability in harvest and processing technique may impact the success of fat grafting. This study compared properties of fat grafts produced by differing methods and assessed volume retention of the grafted tissue in a nude mouse model. Methods: In phase I, fat was harvested by either suction-assisted lipoaspiration or ultrasound-assisted lipoaspiration and then filtered using two different pore sizes. Graft material was analyzed for average parcel size; relative oil, fat, and aqueous fractions; and stromal vascular fraction yield. Filtrands and filtrates were injected into athymic nude mice. In phase II, lipoaspirate harvested by suction-assisted lipoaspiration only was processed by centrifugation, cotton gauze rolling, or filtration, and then studied in a similar manner. Results: Fat harvested by ultrasound- and suction-assisted lipoaspiration had comparable stromal vascular fraction counts and graft retention in vivo. Ultrasound-assisted lipoaspiration released only slightly more oil than suction-assisted lipoaspiration; filtering with either 500- or 800-mu m pore size effectively removed fluid and oil. Centrifugation, cotton-gauze rolling, and filtration also effectively removed fluid and oil. In vivo graft retention and stromal vascular fraction yield was highest with the cotton gauze method. Histologic analysis of all explants showed intact adipose tissue. Conclusions: Ultrasound- and suction-assisted lipoaspiration yielded similar retention of fat grafts in a xenograft model. Processing with cotton gauze rolling may be best suited for grafting cosmetically sensitive areas of the body in which optimal retention is critical and lower total graft volumes are needed. Filtration and centrifugation both effectively removed fluid fractions and resulted in comparable graft retention, and are more feasible when larger volumes are required.