Experimental Study On The Improvement Of Fat Purification Technique And Volume Retention Of Ultra-condensed Fat Graft

Background Fat transplantation is widely used as an important technique for soft tissue reconstruction and regeneration.Fat transplantation retention rates are individual and unpredictable.The presence of blood components and oil droplets in injected liposuction increases inflammation and fibrosis in a dose-dependent manner and may be a key factor associated with poor retention.In this study,the purification method of fat transplantation was improved.Medical polymer materials were used to specifically absorb impurities in liquid and free oil droplets in liposuction,screen complete fat particles,absorb free oil droplets and impurities,optimize the graft,and propose a novel fat transplantation strategy.Methods and results The components of fat after centrifugation were analyzed by nhexane leaching method.On this basis,a new purification device was used to concentrate the next 50%fat after centrifugation to obtain super concentrated fat.The Ultra-Condensed Fat(UCF)was analyzed by scanning electron microscopy(SEM)and laser particle size detection.The histological characteristics of UCF transplantation were observed in nude mice.Finally,UCF transplantation was used to treat hemifacial atrophy patients and patients with facial volume loss,and the clinical effect of UCF transplantation was confirmed.The results showed that the content of free oil droplets in UCF was less than 10%,and the diameter of more than 80%fat particles was greater than 1000μm,which had the characteristics of structural integrity,less impurity and high concentration.The 90-day retention rate in animal experiments was significantly higher than that of fat obtained by conventional centrifugation method(57.5±2.7%vs.32.8±2.5%,p<0.001).In addition,histological analysis at the early stage of UCF transplantation showed that small adipocytes promoted early adipogenesis vigorously.At the very early stage after transplantation,UCF grafts became vasculized rapidly,and tissue repair type M2 macrophages appeared at 7 days after transplantation and quickly withdrew from the grafts at 30 days to improve the rapid tissue repair.In clinical application,ultracondensed fat also showed a good application prospect,and the average retention rate was 60.57±5.72%in 12 months after transplantation.Conclusions UCF contains a large amount of fat particles with large particle size,which can promote rapid infiltration of macrophages to promote tissue regeneration and accelerate graft angiogenesis after transplantation.UCF can be used as a fat filler with better tissue stability and tissue health after transplantation.This purification transplantation strategy has a good clinical application prospect and may bring better clinical treatment for patients with soft tissue defects in the future.