Objective To investigate the feasibil ity 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 fatobtained 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 viabil ity 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 gt; 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 lt; 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 fatgraft in the control group. The normal fat cells in the experimental group were significantly more than those in the control group after operation (P lt; 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 lt; 0.05) and no significant difference at 4 and 8 weeks (P gt; 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 viabil ity was also proved in the experimental group. Eleven patients were followed up 2-9 months, and no obvious atrophy or collapses was observed at reci pient site. Conclusion Compared with Coleman technique, core fat graft can keep the structure and viabil ity of harvested fat tissue by avoiding certain damages of fat cell. Therefore, the earl ier 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.
Objective To explore the differences of three-dimensional porous blended silk scaffolds with different sericin ratios in terms of molecular structure, mechanical properties, and biological characteristics. Methods Fibroin/sericin blended aqueous solution [concentration 8% (W/V)] with various sericin ratios 0%, 2%, 4%, 6%, 8%, 10%, 12% and NaCl asa porogen with different particle sizes (125-200, 200-300, 300-450, 450-600, 600-900, 900-1 100 μm) were used to fabricate the three-dimensional porous blended silk scaffolds. Gross observation of the formation of three-dimensional porous blended silk scaffolds of different sericin ratios and pore sizes was performed. Scanning electron microscope (SEM) was used to detect the distribution and diameter of the pore sizes. Its porosity was calculated by l iquids replacement method. X-ray diffractometer (XRD) and fourier transform infrared (FTIR) were used to detect its internal molecular structure. Its mechanical properties, enzyme degration rate in vitro and experiment on SD rats in vivo, and histolgy observation after coculturing homogeneous scaffold (sericin ratio 0-12%, NaCl particle size 600-900 μm) with adipose tissue-derived mesenchymal stem cells (ADSCs) were detected. Results Gross observation showed that the higher of the ratio of sericin protein, the greater of the porogen sizes scope which used to form homogeneous silk scaffolds. The result of SEM showed that the pores of the three-dimensional porous blended silk scaffolds had uniform distribution and was connected with each other. Its pore sizes was in the scope of the porogen sizes, and its porosity all above 90%. The angel corresponding to the characteristic peak of the sericin/fibroin blended scaffolds were 20.6° and 24.6° (XRD), and the wavelength corresponding to the characteristic peak of the sericin/fibroin blended scaffoldswere 3 296, 2 933 and 1 629 cm-1 (FTIR) which was the same as the angel and wavelength corresponding to the characteristic peak of the natural silk. The mechanical properties of the sericin/fibroin blended scaffolds was improved with the increase of sericin ratios, and the compressional resil ience reached 100% when the ratio ≥ 6%. The different ratios of sericin and the different particle size of porogen had no significant effect on the enzyme degradation rate in vitro. The histological observation 14 days after ADSCs-scaffold co-culture indicated that the scaffolds had slow degradation rate, and sl ight inflammatory response in vivo. ADSCs were well attached to the sericin/fibroin blended scaffolds of different sericin ratios, with varied morphology, rich cytoplasm, and nuclear enrichment, the l ight staining ECM was observed surrounding the cells. Conclusion The mechanical property of the three-dimensional porous blended silk scaffolds is improved by silk sericins with ratio ≥ 6% obviously, which will lay the groudwork for further research and making of strengthen silk scaffolds.