Improved Long-term Volume Retention of SVF-gel Grafting with Enhanced Angiogenesis and Adipogenesis
The apoptosis of mature adipocytes after fat grafting can result in chronic inflammation, absorption, and fibrosis, leading to unpredictable outcomes. Selective elimination of mature adipocytes may result in better outcomes and a different underlying retention mode. We previously developed a mature-adipocyte-free product, SVF-gel, derived from lipoaspirate, which eliminates adipocytes while preserving the stromal vascular fraction. This study investigated the retention and regeneration mode of SVF-gel grafting.Methods
Nude mice were grafted with human-derived SVF-gel or Coleman fat. Detailed cellular events over 3 months were investigated histologically and immunohistochemically.Results
The retention rate 90 days after grafting was significantly higher for SVF-gel grafts than for standard Coleman fat (82% ± 15% vs. 42% ± 9%, P < 0.05). Histological analysis suggested that, unlike Coleman fat grafts, SVF-gel grafts did not include significant necrotic areas. Moreover, although adipose tissue regeneration was found in grafts of both groups, rapid angiogenesis and macrophage infiltration were observed at a very early stage after SVF-gel grafting. The presence of small-sized preadipocytes with multiple intracellular lipid droplets in SVF-gel grafts on day 3 also suggested very early adipogenesis. Although some of the cells in the stromal vascular fraction within survived in SVF-gel grafts, most of the newly formed adipose tissue was host-derived.Conclusion
SVF-gel has a high long-term retention rate and a unique adipose regeneration mode, involving prompt inflammation and infiltration of immune cells, stimulating rapid angiogenesis and inducing host-cell-mediated adipogenesis.