人胎盘间充质干细胞促进血管生成

背景：构建组织工程化骨组织的同时，促进种子细胞与材料复合物内血液供应的重建成为研究的关键。胎盘间充质干细胞可以作为骨组织工程研究的种子细胞，研究其分化为血管内皮细胞以及促进血管生成有着重要意义。 目的：观察胎盘间充质干细胞在体外分化为血管内皮细胞以及体内促血管生成作用。 方法：分离培养人胎盘间充质干细胞，鉴定其表面抗原，经血管内皮生长因子和人碱性成纤维细胞生长因子联合体外诱导胎盘来源间充质干细胞向血管内皮细胞定向分化，诱导后细胞通过内皮细胞标志物KDR、v-WF染色鉴定。8只新西兰大白兔制成桡骨中段1.5 cm长的骨缺损模型，分别植入人胎盘间充质干细胞/丝素蛋白/羟基磷灰石和丝素蛋白/羟基磷灰石进行对照。植入后4，12周分别行大体观察、组织学观察和X射线观察，比较骨缺损修复以及血管生成情况。 结果与结论：胎盘间充质干细胞的诱导分化形态明显改变，胞体逐步回缩，立体感增强，内皮细胞标志物KDR、v-WF染色结果阳性。胎盘来源间充质干细胞与丝素蛋白/羟基磷灰石材料复合培养植入后，4周时新骨已开始形成，12周时有部分新生骨组织形成板层骨，骨小梁形成，内可见新生血管形成，而对照组支架材料降解较慢，未见新生血管。说明胎盘来源间充质干细胞体外可以分化为血管内皮细胞，与丝素蛋白/羟基磷灰石材料联合移植能够促进移植物内血管生成，较好的修复骨缺损。

Human placental mesenchymal stem cells promote angiogenesis

BACKGROUND:The blood supply in seed cells and material compounds is the important issue in the construction of tissue engineered bone tissue. Placental mesenchymal stem cells are the potential seed cells in tissue engineering research, and it is of significance to study its differentiation into vascular endothelial cells as well as promotion of angiogenesis.  OBJECTIVE:To explore the effects of placental mesenchymal stem cells differentiating into vascular endothelial cells in vitro and promoting angiogenesis in vivo. METHODS:Human placental mesenchymal stem cells were isolated and cultured. After the cell surface antigens were identified, the placental mesenchymal stem cells were induced with vascular endothelial growth factor and human basic fibroblast growth factor to differentiate into vascular endothelial cells in vitro. Then immunofluorescence staining for endothelial-specific markers KDR and the von Will brand factor were used to characterize the cells after induction. Eight healthy adult New Zealand rabbits were prepared for 1.5-cm defect models in the middle segment of radius. Then the models were implanted with human placental mesenchymal stem cells/silk fibroin/hydroxyapatite while those implanted with silk fibroin/hydroxyapatite were taken as the controls. At weeks 4 and 12 after operation, gross observation, histological observation and X-ray examination of implanted bone were performed to evaluate bone defects healing and angiogenesis. RESULTS AND CONCLUSION:The morphology of induced placental mesenchymal stem cells was obviously changed, showing cell body contraction and enhanced stereognosis. Immunofluorescence staining analysis showed a positivity for endothelial-specific markers KDR and the von Will brand factor. After the human placental mesenchymal stem cells were cultured with silk fibroin/hydroxyapatite compound, new bone formation was visible at 4 weeks, and lamellar bone formed, trabeculation and neovascularization were detected at 12 weeks after implantation. While scaffold materials degraded gradually and no neovascularization was observed in the control group. Experimental findings indicate that, placental mesenchymal stem cells can differentiate into vascular endothelial cells in vitro, and combined transplantation with silk fibroin/hydroxyapatite can promote angiogenesis and repair bone defects.