Emulsified Fat Grafting Accelerates Tissue Expansion By Promoting Expanded Skin Regeneration

Background: Tissue expansion has been applied in tissue repair and reconstruction of large soft-tissue defects.Stromal vascular fraction(SVF)transplantation is a promising treatment in raising expansion efficiency.However,the clinical utilization of SVF is limited due to its conventional collagenase-based production.Objective: The purpose of this study was to evaluate the effect of emulsified fat(EF),a mechanical disrupted fat product with rich SVF,on accelerating tissue expansion.Methods: The microstructure of EF fragments and the proportion of mesenchymal stem cells(MSCs;CD45-/CD34+)in EF were detected.Wistar rats were divided into 3 groups randomly: the 1ml EF group,the0.5ml EF group and the PBS control group.The tissue expansion was carried out twice a week to maintain the intracapsular pressure at 60 mm Hg.After 4weeks,inflation volume and histological changes of the expanded tissues,including collagen content,cell proliferation and capillary density,were observed to evaluate the effect of EF on tissue expansion.Results: Mechanical emulsification effectively destroyed the mature adipocytes.The proportion of MSCs population in the EF fragments was15.40 ± 0.36%.After expansion,the inflation volume and the levels of collagen deposition,cell proliferation and capillary density of the expanded tissue in the 1ml EF group were significantly higher than those in the 0.5ml EF group and the control group(P < 0.05).However,all these regenerative indicators in the 0.5ml EF group showed no statistical difference from that in the control group(P > 0.05).The thickness of the dermal layer showed no significant difference among all three groups.Conclusion: Our findings suggested that emulsified fat grafting can be used as a new alternative to increase tissue expansion efficiency.