TISSUE ENGINEERING CARDIAC CHORDAE

各种血管移植物常用于心血管组织的重建。然而，目前使用的假体或生物假体材料缺乏生长潜力，因此，随后需要在儿科患者成熟时进行替换。组织工程(TE)是一门新兴学科，它提供了从自体细胞和可生物降解的聚合物支架创建替代结构的可能性。因为TE结构包含活细胞，所以它们可能具有生长、自我修复和自我重塑的潜力。将4~6×10~(-6)的杂种犬股静脉混合细胞接种到由聚乙醇酸无纺布片材和L-丙交酯-己内酯共聚物组成的带瓣贴片状可生物降解聚合物支架上，制成组织工程化自体移植物(TEA)。7天后，将同一组犬的三尖瓣索换成茶。术后3、4、5、6个月行血管造影，处死动物。…对植入的TA进行大体和免疫组织学检查。植入的茶叶没有显示出狭窄或扩张的证据。即使在没有任何抗凝治疗的情况下，茶中也没有发现血栓。未在所有标本中观察到聚合物支架的残留物，总体大体外观与天然肺动脉瓣相似。免疫组织化学染色显示，在茶叶的管腔表面存在因子VIII阳性有核细胞。此外，还观察到存在α-平滑肌肌动蛋白和结蛋白阳性细胞的病变。植入的TEA含有足够数量的细胞外基质，既没有闭塞也没有形成动脉瘤。此外，还发现每种茶叶的管腔表面都有内皮细胞排列。这些结果有力地表明，理想的抗血栓形成的移植物是可以生产出来的。由于我们的实验室和临床经验都是令人鼓舞的，我们认为TE入路可能在儿童心血管外科领域作为移植和人工器官使用的一种替代方法发挥重要作用。较少

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 Autografts (TEAs) 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 tricuspid chordae of the same dogs were replaced with TEAs. After 3, 4, 5 and 6 months, angiographies were performed, and the dogs were sacrificed. … More The implanted TAs were examined both grossly and immunohistologically. The implanted TEAs showed no evidence of stenosis or dilatation. No thrombus was found inside the TEAs, 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 TEAs. In addition, lesions were observed where α-smooth muscle actin and desmin positive cells existed. Implanted TEAs 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 TEA. 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