| Background:In recent years,Autologous fat transplantation(AFT)play an increasingly important role in plastic surgery,AFT has been an practical method used for increasing the volume of local soft tissue in the repair area,and has been widely applied to repair tissue reconstruction,breast augmentation,butt augmentation,face rejuvenation,temporal depression,cheek depression,double side of asymmetry,breast reconstruction after breast cancer surgery and other related operation,and AFT recognized as a relatively safe and effective method at present has good biocompatibility,convenient to obtain,abundant in source,good filling effect,and the significant advantages of small trauma.However,the further application and popularization of this technology are limited due to its low survival rate and high absorption rate.Therefore,the key to the success of fat transplantation is to improve the survival rate of autologous fat transplantation.Adipose-derived Stem Cells(ADSCs),a type of mesenchymal stem cell derived from adipose tissue with multidirectional differentiation potential and proliferation ability.Several studies have confirmed that adipose stem cells exert an influence on improving the survival rate of transplanted fat by reducing the time of ischemia which makes the transplanted fat be supplied to the recipient area more quickly.The mechanism of this therapeutic effect may exist for promoting the secretion of VEGF,bFGF,mmp-9,PDGF,TGF-? and other pro-angiogenesis factors,as well as the direct differentiation into new vascular endothelial cells and perivascular cells.ADSCs have an ideal effect in improving the survival rate of transplanted fat.However,the application of stem cells in China and even in the world is still facing many bottlenecks and obstacles,the most critical points are the uncontrollable possibility of stem cell division and differentiation,the limitations of laws and regulations and social ethics.Therefore,how to find a equivalent of ADSCs without complete stem cell bodies remains a thorny issue.Cells have secretory functions,and secretory factors,vesicles and signaling molecules illuminate a role in the regulation of microenvironment and physiological changes.We found exosomes on this basis.Exosomes,with a diameter of 40 ~ 150 nm,is rich in lipids such as cholesterol,sphingomyelin and ceramide on its surface,and contains biological information such as proteins,mRNA and microRNA,playing an important role in cellular microenvironment.Exosomes were found in B lymphocytes in 1996,and these exosomes have subtle biological for stimulating T cell proliferation and inhibiting tumor growth.Subsequently,exosomes were detected in different types of cells cultured in vitro,and numerous cells secreted exosomes under normal and pathological conditions in addition to living cells in vivo.To the best of our knowledge have shown that exosomes derived from normal cells or stem cells can repair damage tissue and even promote regeneration.The research on exosomes and angiogenesis is also an important part of existing studies both in vivo and in vitro.Studies have shown that exosomes derived from normal progenitor or mesenchymal stem cells and umbilical cord stem cells also contain several mediators including VEGFA,CXCL8,il-6,FGF2 and mir-23 a that promote angiogenesis.Previous therapeutic studies have used the angiogenesis factors contained in exosomes to promote the recovery of blood supply in the lesion area in the field of skin injury repair,bone tissue regeneration,terminal limb ischemia and vascular injury repair.Studies have shown that exosomes have the ability to alter angiogenesis processes,including proliferation,migration,and vascular composition of endothelial cells,as well as to increase the expression of angiogenesis related genes and the secretion of related proteins.Objective:The vasogenic effect of exosomes derived from human adipose stem cells was used to improve the blood supply level of transplanted adipose tissue and improve the survival rate of transplanted adipose tissueMethod:In this study,ADSCs were extracted from adipose tissue obtained during autologous fat transplantation with hydrodynamic devices,in this study.In the first step,exosomes derived from adipose stem cells were extracted utilizing classical differential centrifugation method,and the reliability and biology of the exosomes source were verified through multiple approachs.In the second step,the transplanted adipose tissue was injected subcutaneously into the back and wings of nude mice to further explore whether the exosomes derived from adipose stem cells could promote the survival rate of fat transplantation and the underlie mechanism of its therapeutic effect in order to assess the role of adipose stem cell derived exosomes in promoting angiogenesis of fat transplantation.According to the above experimental results,we hope to obtain a safer and more effective method to improve the survival rate of fat transplantation.The aim of this study was to lay the foundations for a safe,effective and clinical-practice paradigm to improve the survival rate of fat transplantation for future reference.Results:hADSCs-exosome can affect the angiogenesis of transplanted adipose tissue by regulating the levels of VEGF and other related expressions in the region,so as to promote the survival of transplanted tissueConclusion:Exosomes from ADSCs can promote the angiogenesis of transplanted fat,accelerate the vascularization of transplanted adipose tissue,and promote the survival rate of transplanted adipose tissue... |
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