INTRODUCTION: Fat graft (FG) absorption rate varies from 20 to 80% in two years. Recently, several bioengineering techniques were applied to improve FG retention rate. Numerous studies investigated the use of adipocyte-derived stem cells (ASC) as FG enrichment. However, ASC production is costly, complex, and time-consuming. In contrast, Nanofat, a combination of lipids, stem cells and growth factors, offers a faster, simpler, and more cost-effective alternative for FG enrichment. OBJECTIVE: This study aims to compare the effects of ASC with those of Nanofat, as a viable option in FG enrichment. MATERIAL AND METHODS: Animals were allocated in three groups: Control group (1 mL fat), ASC group (1 mL fat +1x10 RESULTS: At week 12, ASC and NnF groups showed a higher retention of FG when compared to the Control group (51%, 46%, 12% respectively, p <
0.01). Fibrosis was similar in ASC and Nanofat groups. The Nanofat group showed a higher vascular density then the Control group (p <
0.05). Il-10 gene expression was higher, and Mmp9 was lower in the Nanofat group when compared to the ASC and Control groups. CONCLUSION: This study indicates that enriching FG with both ASC and Nanofat led to an increased retention rate of the FG, suggesting that Nanofat might be a promising alternative for FG enrichment. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .