Hyperbaric Oxygen Improves the Survival and Angiogenesis of Fat Grafts after Autologous Fat Transplantation.

Objective: Currently, autologous fat transplantation (AFT) still has a low graft survival rate. Elevation of the AFT graft survival rate is a challenge. This study investigated the effect of hyperbaric oxygen (HBO) on AFT. Methods: Twelve adult male SD rats were randomly divided into two groups after AFT: the control group (n = 6) and the HBO group (n = 6). The rats were killed at 7, 14, and 28 days after transplantation to take the transplanted adipose tissues. The volume and weight of the tissues were detected. The pathological changes in the adipose tissues were observed after H&E staining. Microvessel density and levels of transforming growth factor- (TGF-) ß, tumor necrosis factor- (TNF-) α, and malondialdehyde (MDA) in the transplanted adipose tissues were measured with CD31 immunohistochemical stain, ELISA, and biochemical reagents, respectively. Additionally, the protein expression levels of vascular endothelial growth factor- (VEGF-) A and platelet-derived growth factor- (PDGF) A in the adipose tissues were detected by Western blot. Results: HBO significantly preserved the volume and weight of the transplanted adipose tissue (p < 0.01) and maintained the pathological structure of the transplanted adipose tissue. HBO therapy was effective in reducing inflammatory factor (TGF-ß and TNF-α) levels and oxidative stress (MDA) in the transplanted adipose tissue (p < 0.01) and significantly increased the level of CD31 and angiogenesis-related factors including VEGF-A and PDGF-A (p < 0.01) to promote angiogenesis. Conclusion: HBO therapy regulated the immune response of fat grafts, stimulated their angiogenesis, and ultimately promoted their survival after AFT.

[EXPERIMENTAL RESEARCH OF CORE FAT TRANSFER WITH DIFFERENT DIAMETERS].

OBJECTIVE: To investigate the survival rate of core fat tissue with different diameters by advanced fat harvesting instrument. METHODS: Based on core fat transfer by 1 mL syringe, the fat harvesting instrument was modified with different diameters, including 4, 6, 8, and 10 mm respectively. Between May 2014 and April 2015, the fat harvesting instrument with diameters of 4, 6, 8, and 10 mm was respectively used to harvest abdominal fat in 3 of 12 patients undergoing autologous fat transplantation. The glucose transportation quantities and the fat cell viability were measured. Then 64 nude mice at the age of 3-4 weeks were randomly divided into 4 groups (groups A, B, C, and D, n=16). And 0.5 mL fat harvested with diameters of 4, 6, 8, and 10 mm was implanted into the dorsal subcutaneous space. After fat transplantation, the mice survival and the appearance at the recipient site were observed. At 1, 2, 4, and 8 weeks after fat transplantation, the grafted fat was harvested for gross, histological and immunohistochemical observations; the intact adipocytes and capillary were counted. RESULTS: The glucose transportation quantities gradually increased with increased diameter, showing significant difference among groups (P<0.05). And the fat cell viability had a rising tendency, showing significant differences when comparing groups A and B with group D (P<0.05). With the time passing by, the protuberant appearance became flat at the recipient site, but the appearance of groups C and D was better than groups A and B. Normal shape of the fat and capillary were found in groups C and D. At immediate and 1 week after fat transplantation, there was no significant difference in fat weight among 4 groups (P>0.05); the fat weight of group A was significantly less than that of groups B, C, and D (P<0.05) at 2, 4, and 8 weeks after fat transplantation, and it was significantly less in group B than groups C and D (P<0.05), but no significant difference was found between groups C and D (P>0.05). Histological and immunohistochemical observations showed better integrity of the cells, less necrosis, and higher vascular density in group D than groups A, B, and C as time extension. The adipocyte integrity of group A was significantly worse than that of other 3 groups at other time points (P<0.05) except at 1 week (P>0.05). At each time point, the capillary counting had an increasing trend with increased diameter in all groups, showing significant difference among groups (P<0.05). CONCLUSION: With diameters within 10 mm, the thicker the core fat is transferred, the better integrlity, higher vessel density, and quicker revascularization time can be predicted. So the postoperative appearance could be maintained longer.

[Experimental and primary clinical research of core fat graft].

OBJECTIVE: To investigate the feasibility of core fat transfer by comparing with traditional Coleman technique. METHODS: The fat was obtained from 11 patients scheduled for fat transfer by 2 ways: Coleman's method and core fat graft. The latter was harvested by a modified 1 mL syringe. Then 48 nude mice at the age of 3-4 weeks, male or female, weighing 8.6-12.2 g, were divided into 2 groups randomly (n = 24). The dorsal subcutaneous space was recipient site. In the experimental group, 0.5 mL core fat was transplanted into dorsal subcutaneous space; in the control group, 0.5 mL fat obtained by Coleman's method was transplanted into the same site. The appearance of the back was observed after operation; fat specimens were procured at 1, 2, 4, and 8 weeks after operation for the gross, histological, and immunohistochemical observations; and the residual weight of free fat-graft was calculated by the difference between pre- and post-operative mouse weights. The glucose transportation quantities and cell viability were measured immediately after obtaining fat. Facial augmentation procedure was performed with core fat graft in 11 patients with local depressed deformity between May 2010 and October 2011. RESULTS: The uplift of the back was maintained in the experimental group, but the back of mice became flat in the control group at 2 weeks postoperatively. There was no significant difference in the weight of fat-graft between 2 groups (P > 0.05). The residual weight of fat-graft in the experimental group was significantly higher than that in the control group at the other time (P < 0.05, except for 2nd week postoperatively). The histological observation showed good cell morphology and well-distributed vessels in the experimental group, but obvious destruction of the cells and most vessels at the edge of fat-graft in the control group. The normal fat cells in the experimental group were significantly more than those in the control group after operation (P < 0.05), except for 2nd week). The capillaries in the experimental group were fewer than those in the control group, showing significant differences at 1 week and 2 weeks (P < 0.05) and no significant difference at 4 and 8 weeks (P > 0.05). The glucose transportation quantities in the experimental group [(1.462 +/- 0.080) mmol/L] was significantly higher than that in the control group [(1.153 +/- 0.199)mmol/L] (t = 3.317, P = 0.021). The higher cell viability was also proved in the experimental group. Eleven patients were followed up 2-9 months, and no obvious atrophy or collapses was observed at recipient site. CONCLUSION: Compared with Coleman technique, core fat graft can keep the structure and viability of harvested fat tissue by avoiding certain damages of fat cell. Therefore, the earlier anastomoses between the host and core graft fat can reduce tissue loss and improve the fat survival. So it is recommended for enblock fat graft.