IL-4 modified expanded polytetrafluoroethylene (e-PTFE) surgical patch promotes angiogenesis in transplanted flap and inhibits inflammatory response.

Skin flap transplantation is one of the most common tissue transplantation methods for wound repair and organ reconstruction in plastic surgery. During the transplantation process, the inflammatory response of transplanted flap and angiogenesis are critical to the successful rate of skin flap transplantation. In recent years, to improve the biocompatibility and cell affinity of biomedical materials, the modified biomaterials have gradually become a popular subject in scientific researches. In our study, the IL-4 modified expanded polytetrafluoroethylene (e-PTFE) surgical patch IL4-e-PTFE was prepared, and the rat skin flap transplantation model was constructed. The results of cell experiment prove that IL-4 has potentiation in the angiogenesis of human umbilical vein endothelial cell (HUVEC) induced by monocyte, and IL-4 can also promote angiogenesis by inducing the M2 macrophages. According to the results of in vivo experiment, the apoptosis level of transplanted flap cells of rats in the IL4-e-PTFE group was lower than that in the e-PTFE group, and in the IL4-e-PTFE group, the expression levels of pro-inflammatory cytokines IL-1ß, IL-6 and TNF-α showed significantly decline compared to the e-PTFE group, while the expression levels of anti-inflammatory cytokines IL-1Ra, IL-10 and TGF-ß presented significant increase compared to the e-PTFE group; the immunofluorescence staining results show that the number of M2 macrophages in transplanted flap area of rats in the IL4-e-PTFE group was significantly higher than that in the e-PTFE group, and the angiogenesis level was remarkably improved. In this study, by preparing IL4-e-PTFE and carrying out the cell and in vivo experiments, a reference method is proposed, which can reduce the inflammatory response during skin transplantation process using e-PTFE and optimize the long-term effects of flap blood vessels, hoping to provide a broader space for the applications of e-PTFE in medicine.

[Biomechanical analysis of different ProDisc-C arthroplasty design parameters after implanted: a numerical sensitivity study based on finite element method].

This study was aimed to estimate the effect of different ProDisc-C arthroplasty designs after it was implanted to C5-C6 cervicalspine. Finite element (FE) model of intact C5-C6 segments including the vertebrae and disc was developed and validated. Ball-and-socket artificial disc prosthesis model (ProDisc-C, Synthes) was implanted into the validated FE model and the curvature of the ProDisc-C prosthesis was varied. All models were loaded with compressed force 74 N and the pure moment of 1.8 Nm along flexion-extension and bilateral bending and axial torsion separately. The results indicated that the variation in the curvature of ball and socket configuration would influence the range of motion in flexion/extension, while there were not apparently differences under other conditions of loads. The method increasing the curvature will solve the stress concentration of the polyethylene, but it will also bring adverse outcomes, such as facet joint force increasing and ligament tension increasing. Therefore, the design of artificial discs should be considered comprehensively to reserve the range of motion as well as to avoid the adverse problems, so as not to affect the long-term clinical results.