Arteries Engineered from Porcine Vascular Cells

由猪血管细胞改造而成的动脉

• 批准号: 6625865
• 负责人: LAURA E NIKLASON
• 金额: $ 28.1万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2006-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6625865
• 关键词: amine oxidoreductase; artery; clotting factor; collagen; copper; crosslink; dietary supplements; elastin; enzyme activity; enzyme inhibitors; immunocytochemistry; metalloendopeptidases; method development; miniature swine; northern blottings; retinoate; thrombomodulin; thrombosis; tissue /cell culture; tissue engineering; tissue inhibitor of metalloproteinases; transmission electron microscopy; vascular endothelium; western blottings

Every year, nearly 100,000 patients need coronary or peripheral revascularization procedures, but have no suitable vein or artery. The tissue engineering of autologous vessels for these patients could have an enormous impact on therapy for cardiovascular disease. We have developed techniques to culture tissue engineered vessels from differentiated vascular cells. Engineered arteries are cultured on degradable polymer scaffolds in pulsatile perfusion systems. Vessels that are produced are strong enough for initial implantation. Completely autologous animals grafts, as well as human engineered vessels, have cultured using these methods. However, implanted autologous vessels dilate significantly over time in vivo, due to limitations in ultimate mechanical strength. In addition, engineered graft survival in animal models is limited by thrombosis. Thus, although significant advances have been made in vascular tissue engineering, mechanical strength and thrombogenicity limit further progress in the field. Collagen determines the ultimate mechanical properties of blood vessels. Engineered blood vessels have less collagen than native vessels, and this collagen has lower load-bearing properties than native. We postulate that the "defective" collagen in engineered vessels is caused by inadequate cross-linking, and by excessive cleavage by proteases. This proposal will test this overall hypothesis. Specifically, we will study the effects on collagen cross-linking of copper supplementation to increase lysyl oxidase activity. In addition, we will study the effects of metalloproteinase inhibition on collagen accumulation and vessel strength, and we will assess the effects of retinoids on cross- linking activity, metalloproteinases, and cellular quiescence in engineered vessels. These experiments will thus work synergistically to improve tissue engineered collagen, and hence improve vessel mechanical strength. The other important limitation for engineered vessels is early thrombosis. Cultured endothelial cells decrease expression of thrombomodulin, which is an important anti-coagulant in the native arterial system. We will examine the functional significance of thrombomodulin loss in engineered vessels. With the aim of improving the patency of these vascular grafts, we will also quantify the effects of thrombomodulin over-expression on vessel thrombogenicity. Thus, by attacking the two important impediments in vascular tissue engineering, the experiments in this proposal will significantly advance the field.

每年，近100,000名患者需要冠状动脉或外围血运重建手术，但没有合适的静脉或动脉。 这些患者自体血管的组织工程可能会对心血管疾病的治疗产生巨大影响。 我们已经开发了从分化的血管细胞培养组织工程血管的技术。工程动脉在脉冲灌注系统中可降解的聚合物支架上进行培养。 生产的血管足够强，可以初始植入。 完全自体的动物移植物以及人类工程血管已经使用这些方法进行了培养。 然而，由于最终机械强度的限制，植入的自体血管随着时间的流逝而随着时间的流逝显着扩张。 此外，动物模型中的工程移植物生存受到血栓形成的限制。 因此，尽管在血管组织工程，机械强度和血栓形成性限制了该领域的进一步进步中，尽管已经取得了重大进展。胶原蛋白确定血管的最终机械性能。 工程血管的胶原蛋白比天然血管少，并且该胶原蛋白的承载特性低于天然。 我们假设工程容器中的“有缺陷”胶原蛋白是由交联不足以及蛋白酶过度裂解引起的。 该建议将检验这一总体假设。 具体而言，我们将研究补充铜的胶原蛋白交联的影响，以增加赖氨酸氧化酶活性。 此外，我们将研究金属蛋白酶抑制对胶原蛋白积累和血管强度的影响，我们将评估类视视性类动物对工程血管中交叉连接活性，金属蛋白酶和细胞静止的影响。 因此，这些实验将协同起作用，以改善组织工程的胶原蛋白，从而改善血管机械强度。工程血管的另一个重要局限性是早期血栓形成。 培养的内皮细胞降低了血栓统治的表达，血小板统治是天然动脉系统中重要的抗糖剂。 我们将研究工程血管中血小板蛋白损失的功能意义。 为了改善这些血管移植物的通畅性，我们还将量化血小板调节蛋白过表达对血管血栓形成性的影响。 因此，通过攻击血管组织工程中的两个重要障碍，该提案中的实验将显着前进。