Development of Novel Biodegradable Scaffold for Non-Cell-Seeding In-vivo Tissue-Engineering Vasculature and It's Clinical Applications

我们已经开发了一种新的可生物降解的支架，它在植入之前不需要任何细胞准备步骤来创建原位组织工程血管系统(ITEV)。进行动物实验，以检验其特性和长期疗效。将聚乙交酯针织纤维和L-丙交酯-己内酯共聚物海绵外加乙交酯-e-己内酯共聚物单丝增强的8 mm管状可生物降解支架植入犬下腔静脉。在每次实验之前，所有的狗都活得很好，根据研究，iTEV的实用性被评估了1到24个月。血管内超声和压力测定的iTEV弹性模数在1个月后达到并保持了天然IVC的90%左右。2年的iTEV血管造影显示血管形成良好，再生良好，无明显狭窄或血栓形成，平均压力梯度较低。与原始植入支架的长度相比，iTEV的长度延长了2年。组织学检查显示血管样血管结构良好，无钙化。生化研究表明，与天然下腔静脉相比，羟脯氨酸、弹性蛋白和钙的含量没有显著差异。这些结果为这种新型支架在血管组织工程中的应用提供了直接的证据。长期的结果表明，iTEV质量良好，其形状适应了活体的需要。因此，这种支架将适用于使用生物相容性材料的儿科心血管手术。

We have developed a new biodegradable scaffold that does not require any cell preparation steps before its implantation to create an in-situ tissue-engineering vasculature ( iTEV). Animal experiments were conducted to test its characteristics and long-term efficacy. Eight-millimeter tubular-shaped biodegradable scaffolds which consist of polyglycolide knitted fiber and L-lactide and -caprolactone copolymer sponge with outer glycolide and e-caprolactone copolymer monofilament reinforcement were implanted into canine inferior vena cava (IVC). All canines were well alive until each experiment, and the utility of the iTEV was evaluated from 1 to 24 months according to the studies. The elastic modulus of iTEV determined by intravascular ultrasound and pressure studies reached and kept about 90% of native IVC after 1 month. Angiography of 2-years iTEV showed well-formed and regenerated vasculature without marked stenosis or thrombosis with the low mean pressure gradient. The length of 2-years iTEV extended when compared to the length of the original implanted scaffold. Histological studies revealed well-formed vessel-like vasculature without calcification. Biochemical studies showed no significant difference in hydroxyproline, elastin, and calcium content when compared to native IVC. These results provide direct evidence that this new scaffold can be useful for cell free tissue-engineering of vasculature. The long-term results revealed that the iTEV was of good quality and adapted its shape to the needs of the living body. Therefore, this scaffold would be applicable for pediatric cardiovascular surgery involving biocompatible materials.