TISSUE ENGINEERING HEART VALVE

各种血管移植是心血管组织重建的常用方法。然而，目前使用的假体或生物假体材料缺乏生长潜力，因此，在儿童患者中，随着它们的成熟，随后需要更换。组织工程（TE）是一门新的学科，它提供了从自体细胞和可生物降解的聚合物支架中创建替代结构的潜力。由于TE结构含有活细胞，它们可能具有生长、自我修复和自我重塑的潜力。将杂种犬股静脉中提取的4-6 × 10^6个混合细胞植入到聚乙醇酸（PGA）无纺布片和l-丙交酯-己内酯共聚物（N=4）组成的带瓣片状可生物降解聚合物支架上，制备组织工程血管自体移植物（TEVAs）。7 d后，将同一组狗的下腔静脉（IVCs）替换为teva。术后3、4、5、6个月行血管造影，处死更多g。对植入的teva进行粗观和免疫组织学检查。植入的teva没有出现狭窄或扩张的迹象。在未进行抗凝治疗的情况下，teva内未发现血栓。所有标本均未观察到聚合物支架的残余，总体大体外观与天然肺瓣膜相似。免疫组织染色显示在teva管腔表面存在因子VIII阳性有核细胞。此外，在α-平滑肌肌动蛋白和desmin阳性细胞处观察病变。植入的TEVAs含有足量的细胞外基质，未出现闭塞或动脉瘤形成。此外，内皮细胞排列在每个TEVA的管腔表面。这些结果强烈表明可以产生具有抗血栓形成性的“理想”移植物。由于我们的实验室和临床经验都非常令人鼓舞，我们建议TE方法可能在儿科心血管外科领域作为移植和人工器官使用的替代方法发挥重要作用。少

Various vascular grafts are commonly used in the reconstruction of cardiovascular tissues. However, currently used prosthetic or bioprosthetic materials lack growth potential and, therefore, subsequently require replacement in pediatric patients as they mature. Tissue engineering (TE) is a new discipline that offers the potential to create replacement structures from autologous cells and biodegradable polymer scaffolds. Because TE constructs contain living cells, they may have the potential to grow, self-repair, and self-remodel. Tissue Engineered Vascular Autografts (TEVAs) were made by seeding 4-6 x 10^6 of mixed cells obtained from femoral veins of mongrel dogs onto valved patch-shape biodegradable polymer scaffolds composed of a polyglycolic acid (PGA) non-woven fabric sheet and a co-polymer of l-lactide and-caprolactone (N=4). After 7 days, the inferior vena cavas (IVCs) of the same dogs were replaced with TEVAs. After 3, 4, 5 and 6 months, angiographies were performed, and the do … More gs were sacrificed. The implanted TEVAs were examined both grossly and immunohistologically. The implanted TEVAs showed no evidence of stenosis or dilatation. No thrombus was found inside the TEVAs, even without any anticoagulation therapy. Remnants of the polymer scaffolds were not observed in all specimens, and the overall gross appearance appeared similar to that of native pulmonary valves. Immunohistological staining revealed the presence of Factor VIII positive nucleated cells at the luminal surface of the TEVAs. In addition, lesions were observed where α-smooth muscle actin and desmin positive cells existed. Implanted TEVAs contained a sufficient amount of extracellular matrix, and showed neither occlusion nor aneurysmal formation. In addition, endothelial cells were found to line the luminal surface of each TEVA. These results strongly suggest that 'ideal' grafts with anti-thrombogenicity can be produced. Because both our laboratory and clinical experiences are quite encouraging, we suggest that the TE approach may play an important role as an alternative method to transplantation and to the use of artificial organs in the field of pediatric cardiovascular surgery. Less