Concentrated Deoiled Fat: A Novel Method of Fat Processing to Improve Fat Graft Survival-A Basic Research.

[BACKGROUND] Oil compromises graft outcomes via inflammation, which accounts for the unpredictability of volume retention rates as low as 20%. Existing techniques for oil removal are relatively inefficient. In this study, a novel approach was taken to prepare concentrated deoiled fat (CDF) by utilizing flocculation and centrifugation to remove the oil. The hypothesis put forward in this study was that CDF would exhibit improved volume retention and quality by enhancing purification efficiency and reducing inflammation.

[METHODS] This basic research involved both in vitro and in vivo experiments using samples obtained from women who underwent abdominal liposuction. The CDF was prepared by flocculation and centrifugation. In the vitro experiments, the microstructure of fat was assessed using Calcein acetoxymethyl ester (AM) staining for living cells and propidium iodide (PI) staining for dead nuclei in two groups: Coleman fat group and CDF group. Additionally, the glucose uptake capacity of these two groups was evaluated using the glucose transport test (GTT). In the vivo experiments, the study included three groups: two experimental groups (low-volume concentrated deoiled fat, LCDF; high-volume concentrated deoiled fat, HCDF) and one control group (Coleman fat), with 10 healthy female BALB/c nude mice in each group, 1ml of the graft was injected subcutaneously to each mouse. After 8 weeks, the fat grafts were harvested and subjected to volume evaluation, HE staining and immunostaining for perilipin to assess graft outcomes.

[RESULTS] In the vitro experiments, the concentration rate of the CDF was found to be 79.6% that of Coleman fat, with 15.1% more oil separated. Cell viability, as assessed by AM/PI staining, did not show a significant difference between the two grafts, but the results of the GTT showed that the tissue viability of the CDF was higher than that of Coleman fat. In the vivo experiments, the CDF had higher volume retention than Coleman fat, as measured by water displacement. Histopathologic scoring indicated that HCDF group and LCDF group had a more intact fat structure with fewer vacuoles, inflammation, and fibrosis compared to Coleman fat. Additionally, the percentages of perilipin-positive area in the LCDF group and HCDF group were higher than in the Coleman group, indicating improved graft quality and outcome with the use of concentrated deoiled fat.

[CONCLUSIONS] "Concentrated deoiled fat" refers to an autologous fat graft from which oil has been removed by flocculation and centrifugation. This process increases volume retention and viable cells and decreases infiltrated inflammatory cells.

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