骨髓基质干细胞-组织工程瓣膜的新细胞来源

目的：比较人骨髓基质干细胞与人瓣膜间质细胞抗原表达和分泌基质的特点，探讨人骨髓基质干细胞用于构建组织工程瓣膜的可行性。方法：体外培养、扩增人骨髓基质干细胞和人瓣膜间质细胞，比较形态学和生长特性，免疫荧光和流式细胞仪检测比较两者的抗原表达，免疫组织化学检测两者的细胞外基质分泌。扫描电镜观察MSC在瓣膜支架上的附着。结果：骨髓基质干细胞具有肌成纤维细胞的形态，细胞型分析显示α平滑肌肌动蛋白和波形蛋白阳性，平均荧光强度比分别为4．9和3．8，表达量与瓣膜间质细胞(2．4和3．1)接近。MSC分泌I型和Ⅲ型胶原蛋白，组织学和扫描电镜可见骨髓基质干细胞在瓣膜表面生长旺盛，具有正常的分泌功能和形态。结论：骨髓基质干细胞易于从体内分离、扩增，具有和瓣膜间质细胞相似的形态、抗原表达和功能，可以在去细胞猪主动脉瓣膜附着和扩增，形成组织，显示MSC是一种有前途的细胞，可以作为瓣膜组织工程的种子细胞来源。

Human Marrow Stromal Stem Cells-a New Cell Source for Heart Valve Tissue Engineering

Objective: Human marrow stromal cells (MSC) exhibit the potential to differentiate into multiple cell-lineages and can be easily obtained clinically. This study was designed to assess the feasibility of using human MSC cells to construct tissue engineering heart valve. Methods: Bone marrow was aspirated from the sternum of adult. Cells were isolated using Ficoll gradient, cultured, and characterized based on immunofluorescent staining, flow cytometry, histology, and immunohistochem-istry. Subsequently MSC cells were delivered onto a decellularized porcine aortic heart valve scaffold and cultured for 5 days, The tissue - engineered valves were assessed by scanning electron microscopy. Interstitial cells derived from the human rheumatic aortic heart valves were cultured in vitro as contrast. Results: Isolated MSC demonstrated fibroblast - like morphology, Phenotype analysis revealed positive signals for alpha - smooth muscle actin and vimentin. Flow - cytometry of MSC pre - seeding was negative for CD31, CD14, positive for ASMA, vimentin and the mean fluorescence intensity ratio (MFIR) was same as the interstitial cells. SEM demonstrated cell typical of viable, secretionally active marrow stromal stem cells. Conclusion: Marrow stromal cells can be isolated noninvasively from the sternum demonstrated myofibroblast - like characteristics and can adhere to and populate on decellularized porcine aortic heart valve. Thus, bone marrow may be a potential source of cells for tissue engineering heart valves.