Concentrated ultrasound-processed fat (CUPF): More than a mechanically emulsified graft.

INTRODUCTION: Autologous fat grafting is still an evolving technique. Researchers have attempted to increase the survival rate of grafts by concentrating adipose-derived stem cells (ASCs). In this study, we investigate a novel method that combines ultrasonic processing and centrifugation to generate small fat particles termed concentrated ultrasound-processed fat (CUPF) for grafting.

METHODS: The standard approach for obtaining CUPF is described. The properties of processed fat, including CUPF, microfat, centrifuged fat, and nanofat, were investigated using histological observation. Comparative analyses were conducted on the cell number, viability, and immunophenotypic profile of stromal vascular fraction cells (SVFs). Cultured ASCs were evaluated for cell proliferation and adipogenic, osteogenic, and chondrogenic potential. The processed fats were transplanted and evaluated using in vivo and histological studies.

RESULTS: Compared with microfat, centrifuged fat, and nanofat, CUPF had a condensed tissue content and higher concentration of viable cells in a small tissue structure and could smoothly pass through a 27-gauge cannula. In the CUPF group, SVFs were isolated in great numbers, with high viability and a high proportion of CD29- and CD105-positive cells. ASCs from the CUPF group exhibited high proliferation and multilineage differentiation potential. The grafts from the CUPF group were well preserved, and histological quantification revealed an increase in the abundance of Ki67- and CD31-positive cells in the tissue.

CONCLUSIONS: Our study established a new fat processing strategy that combines ultrasonic processing and centrifugation to harvest small particle grafts named CUPF. CUPF concentrated a large number of ASCs and has great potential for regenerative therapy.