Experimental Study And Clinical Application Of SVF-gel:a High Concentrate Adipose Tissue-derived Stem Cells/Extracellular Matrix Complex

BackgroundThe application of current adipose-derived stem cells(ASCs)has been extended to many fields of clinical application.The most common field of plastic surgery is the application of fat transplantation.However,the bottleneck of clinical application of ASCs is very prominent,such as the complexity of the separation process,the need to introduce exogenous dissimilar eunzyme protein to digest tissue,and so on.Use the traditional chemical digestion method to obtain stromal vascular fraction(SVF)cells,the result is cell suspension.Cells are not adherent to the extracellular matrix(ECM)on the physiological state,so easy to be engulfed by host macrophages.Mature adipocytes and ASCs can not survive long,which is leading to the retention rate instability.The report on Nanofat in 2013 gave us an inspiration for the treatment of adipose tissue into an approximately stem cell suspension by physical method,which resulted in intradermal injection and achieved the effect of stem cell therapy.This method selectively destroys adipocytes,which can be injected by sharp needles,and the main cellular components are SVF cells.But because of its large amount of swelling fluid and lipid droplets,the concentration of SVF cells is much lower than that of stem cell therapy.Is it possible to obtain high-level SVF/ASC cells by purely physical means while preserving the protective ECM at the same time?We have obtained a product of enrichment of SVF and ECM by further processing of Nanofat,which we named adipose extracellular matrix/stromal vascular fraction gel(ECM/SVF-gel).This paper will introduce ECM/SVF-gel acquisition,component analysis,as stem cell therapy,tissue transplantation materials and clinical application related experimental studies.Methods and resultsWe developed a novel but simple method for generating an injectable mixture of SVF cells and native adipose extracellular matrix(ECM).It is a purely mechanical process in which lipoaspirate is processed into an "ECM/SVF-gel".The standard processing procedure was established using quantized tests.The therapeutic potential of ECM/SVF-gel for wound healing was then tested in an animal model.In another animal experiment,the differences in long term retention rate and histological/cytological changes of the graft between ECM/SVF-gel and fat were tested with a nude mouse.SVF-gel grafting was performed in 126 cases for skin rejuvenation(dark lower eyelids and neck rhytides)and facial volume augmentation.Four clinical cases are described.ECM/SVF-gel derived from lipoaspirate and processed using a standard Coleman technique,followed by 1 min of mechanical processing by passage back and forth between two 10-m1 syringes at a flow rate of 10 ml/sec,showed the highest ASC and endothelial cell density(1.9 ± 0.2 × 105 cells/ml and 7.7 ± 2.4 ×104,respectively).The SVF cells within the ECM/SVF-gel also showed potential for multipotent differentiation similar to that of cells from normal fat samples.Additionally,the ECM/SVF-gel showed better therapeutic results than SVF cell suspension when used to treat a nude mouse model of wound healing.The retention rate of ECM/SVF-gel graft was significantly higher than standard Coleman fat day 90 after grafting(82.3 ± 3.9%and 42.1 ± 3.3%,respectively).Histological analysis suggested that unlike fat graft,there was no significant necrotic area in ECM/SVF-gel graft,rapid adipogenesis and angiogenesis were observed at a very early stage.Clinical applications showed remarkable improvements in skin quality and facial contour.The result also showed no bruises or swelling after injection.No infections,fat cysts,granulomas,or other unwanted side effects were observedConclusionsECM/SVF-gel is an autologous injectable derived of native ECM and is a functional cellular component generated using a simple mechanical process.As such,it may offer a novel mode of tissue repair suitable for clinical application in stem cell therapies.Compared with fat grafting,ECM/SVF-gel grafting would lead to a more stable volume retention and mild inflammatory response in the recipient site.It appears suitable for both skin rejuvenation and volume augmentation procedures.