利用人骨髓基质干细胞构建组织工程心脏瓣膜的体外实验

背景：目前临床应用的人工瓣膜，无论机械瓣还是生物瓣都存在着诸如易感染、出血和血栓形成并发症，因瓣口狭窄需再手术等自身难以克服的缺陷。理论上具有生物活性的组织工程心脏瓣膜可克服上述缺点，但种子细胞和瓣膜支架的选取尚存在争议。目的：探讨应用人骨髓基质干细胞及脱细胞猪主动脉瓣支架体外构建组织工程瓣膜的可行性。方法：采用去垢剂一核酸酶消化法处理，去除猪主动脉瓣叶细胞成分，获取施行简单先心病修补患者胸骨来源的骨髓基质干细胞，将其种植于脱细胞猪主动脉瓣支架共培养5d。结果与结论：流式细胞技术证实接种的种子细胞的表面抗原符合人骨髓基质干细胞的特征；光镜及电镜检查证实，猪主动脉瓣膜中的细胞成分可完全去除，获得完整无细胞的纤维网状支架；瓣叶去细胞前后的生物力学性能无明显变化；种植的人骨髓基质干细胞可在脱细胞猪主动脉瓣支架表面形成一层连续的细胞层；接种的人骨髓基质干细胞有向成纤维细胞分化的趋势。以上结果提示种植人骨髓基质干细胞于脱细胞猪主动脉瓣支架上，可构建出组织工程心脏瓣膜。

Reconstruction of tissue-engineered heart valve with human bone marrow stromal stem cells in vitro

BACKGROUND： Nowadays, mechanical or biological valve recipients used in the clinic are still at the risk of infection, hemorrhage, thrombosis and reoperation owing to valve stenosis. Tissue-engineered heart valve with biological activity can overcome the disadvantages above. While, the optimal choice of scaffolds and seeding cells remains disputable. OBJECTIVE： To explore the feasibility to construct tissue-engineered heart valve with acellularized porcine aortic valve scaffold and human bone marrow stromal stem cells in vitro. METHODS： The porcine aortic valves were decellularized with the detergent and enzymatic extraction process to remove the cellular components. Human bone marrow stromal stem cells were aspirated from sternum of the patients with simple congenital heart malformation, and then the cells were seeded on the acelluladzed porcine aortic valve scaffold and cultured for 5 days. RESULTS AND CONCLUSION： Flow cytometry identified that the characteristics of surface antigen of the inoculated seed cells were in line with those of human bone marrow stremal stem cells. Light microscopy and electron microscopy confirmed that the cellular components in the porcine aortic valves could be removed to obtain the complete acellular fiber mesh stent. There was no significant difference in biomechanical property between before and after acellularization. The human bone marrow stremal stem cells implanted on the acellularized porcine aortic valve scaffold could form a continuous cell layer on the surfaces of the scaffold. The inoculated bone marrow stromal stem cells could be differentiated into fibroblasts. The implantation of human bone marrow stromal stem cells on the acellularized porcine aortic valve scaffold can construct the tissue-engineered heart valve.