Adipose-derived regenerative cell (ADRC)enriched fat grafting: optimal cell concentration and effects on grafted fat characteristics

Background: To overcome the absorption of traditional fat grafting, techniques for adipose-derived regenerative cell (ADRC)-enriched fat grafting are currently being adapted for practical application. The Celution r 800/CRS (Cytori Therapeutics, San Diego, CA) has enabled rapid grafting of the patient's own freshly harvested ADRCs without requiring a culturing step. However, the optimal cell concentration and the effects of ADRCs on the characteristics of grafted fat after free fat grafting remain unclear. Methods: ADRCs were isolated and purified from human fat tissue using the Celution r 800/CRS. Animals that received fat grafting without the addition of ADRCs were designated the control group (group A). The number of ADRCs per grafted fat volume (mL) was adjusted to 3 x 10(5), 1.5 x 10(6), and 3 x 10(6) cells/mL (groups B, C, and D, respectively), mixed with free fat, and transplanted as ADRC-enriched fat grafting. These mixtures were transplanted subcutaneously into BALB/C Jcl-nu/nu mice. The volume of grafted fat was determined 5 months after transplantation, and histological assessments were performed. Results: ADRC-enriched fat grafting resulted in decreased fat absorption and the formation of greater numbers of new blood vessels in the grafted fat. The optimal ADRC concentration in this study was found to be 3 x 10(5) cells/mL (group B), with higher concentrations resulting in increased cyst and fibril formation in the grafted fat. Conclusions: This study used the Celution r 800/CRS for free fat grafting and demonstrated that the concentration of transplanted ADRCs affected the engraftment and quality of the grafted fat.