Optimized Autologous Fat Grafting: Effect On Harvesting, Manipulation and Live Mesenchymal Stromal Cells

Purpose: The use of adipose tissue as a soft-tissue filler has shown to be attractive because it is readily available, inexpensive, host compatible and has been identified as an abundant source of mesenchymal stem cells. Unfortunately in practice, fat transplantation often has unreliable long term results mostly due to tissue resorption and volume loss. To this day, there is no agreement as to the best way of processing the fat to ensure maximum take and viability of the graft. The purpose of this study was to compare the effects of the three most common fat processing techniques used in plastic surgery, on the viability and number of cellular components of aspirated adipose tissue in order to determine a method that can yield higher concentrations of viable adipocytes and mesenchymal stem cells.

Methods/Technique: Fat harvested manually from the lower abdomen of twenty female patients undergoing liposuction, was divided and processed by decantation, washing and centrifugation. Each processed sample was analyzed by histological techniques after PAS staining for adipocyte count and morphology and was submitted to mechanical dissociation for analysis by multicolor flow cytometry and culture for identification of adipose-derived stem cells.

Results/Complications: Intact nucleated adipocyte count was significantly greater in decanted lipoaspirates, where centrifuged samples showed a great majority of altered adipocytes. Quantification by flow cytometry of endothelial and mesenchymal stromal cells showed a great loss in the middle layer of centrifuged lipoaspirates (used for grafting) as compared to washed lipoaspirates. However the pellet collected at the bottom of the centrifuged samples showed the highest concentration.

Conclusion: Considering the importance of regenerative cells for graft survival, centrifugation although very aggressive on adipocytes, cleared the fat of most blood remnants and showed the highest concentration of MSCs in the pellet that could be extracted and added to other tissues or substances to increase survival. However, the washing process not only cleared lipoaspirates of most blood remnants and other harmful substances, but was also less aggressive on the adipocytes and maintained a great quantity of adipose-derived mesenchymal stem cells. In other terms, washing seemed to be the best processing technique for adipose tissue graft take as it maintains the quantity, integrity and viability of the most important components of aspirated adipose tissue.

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