TISSUE ENGINEERING CARDIOVASCULAR STRUCTURES

各种血管移植物通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，随着其成熟，随后需要在儿科患者中进行更换。组织工程（TE）是一门新学科，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潜力。由于TE构建体含有活细胞，因此它们可能具有生长、自我修复和自我重塑的潜力。组织工程血管自体移植物（TEVA）是通过将4-6 × 10^6个从杂种狗股静脉获得的混合细胞接种到管状生物可降解聚合物支架上制成的，该支架由聚乙醇酸（PGA）无纺布片和l-丙交酯和-己内酯的共聚物（N=4）组成。七天后。用TEVA替换相同狗的下腔静脉（IVC）。术后3、4、5、6个月行血管造影。狗狗们 关于我们 牺牲了。对植入的TEVA进行大体和免疫组织学检查。植入的TEVA未显示狭窄或扩张迹象。即使没有任何抗凝治疗，TEVA内也没有发现血栓。在所有样本中均未观察到聚合物支架的残留，总体外观与天然IVC相似。免疫组织学染色显示在TEVA的管腔表面存在因子VIII阳性有核细胞。此外，在α-平滑肌肌动蛋白和结蛋白阳性细胞存在的地方观察到病变。植入的TEVA含有足够量的细胞外基质，并且未显示闭塞或血管瘤形成。此外，内皮细胞被发现内衬每个TEVA的管腔表面。这些结果强烈地表明，“理想的”静脉移植物具有抗血栓形成可以产生。使用TE技术。使用自体静脉细胞在一个4岁女孩中成功地重建了外周肺动脉。闭塞的肺动脉用TE血管移植物重建。无术后并发症发生。在随访血管造影中，发现移植血管完全通畅。显然需要长期跟踪以确认这一方法的可行性。然而.鉴于我们的成功，我们现在计划继续使用这种TE技术，仅在低压血管中使用自体细胞，例如静脉或肺循环。因为我们的实验室和临床经验是相当令人鼓舞的，我们认为TE的方法可能会发挥重要作用，作为一种替代方法移植和使用人工器官在儿科心血管外科领域。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 tube-shaped 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 dogs wer … More e 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 IVCs. 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' venous grafts with anti-thrombogenicity can be produced. Using the TE technique. a peripheral pulmonary artery was successfully reconstructed in a 4-year-old girl using autologous venous cells. The occluded pulmonary artery was reconstructed with the TE vessel graft. No postoperative complications occurred. On follow-up angiography, the transplanted vessels was noted to be completely patent. Long-term follow up is obviously necessary to confirm the feasibility of this approach. However. given our success, we now plan to continue to use this TE technique with autologous cells in only low pressure vessels, such as the venous or pulmonary circulation. 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