Functional tissue engineering and regeneration of the aortic root

 描述(申请人提供)：对于所有年龄段的患者来说，对高级心脏瓣膜置换术有很大的临床需求。目前的瓣膜替代品提供了极好的生活质量，但耐用性有限，主要是因为这些是非生物植入物。最具生理性的瓣膜置换被认为是同种瓣膜移植物，具有良好的血流动力学，但缺乏细胞。因此，理想的瓣膜替代物将是一种体外再生的活体结构，它接近于模拟主动脉根部独特的生物学和血流动力学特征。主动脉根部由不同的解剖成分、细胞外基质分子和细胞组成，维持平衡的基质动态平衡；这是终身机械耐力的秘诀。我们假设体外有功能的主动脉根再生是可能的，方法是将成体干细胞或预分化的成体干细胞接种于异种无细胞根部的每个解剖部分，并将种植的细胞暴露在受控的机械提示下，以诱导干细胞分化和成熟为靶细胞，以响应“生态位”生物学和生物力学。提出的目的是系统地验证这一假说，方法是用细胞在无细胞牙根内和外种植，然后逐渐暴露于机械刺激适应和动态适应，达到主动脉瓣的血流动力学条件。初步研究证明了每项拟议技术的可行性，包括开发基于微阵列的新播种方法、用于适应的3D旋转器和用于调节的先进阀门生物反应器。已经组建了一个由每个关键领域的世界知名专家组成的多PI团队，以确保成功完成这项研究。预计这样的程序将导致机械坚固、全功能、可存活的主动脉瓣根部填充有代谢活性的细胞，能够进行基质重塑。这将确保植入后立即的血流动力学功能，以及由于持续的细胞介导的基质修复而获得的长期机械和生物稳定性。这些替换瓣膜是在技术先进的集成再生平台的帮助下开发的，将准备好在大型动物身上进行临床前转化测试。

 DESCRIPTION (provided by applicant): There is a great clinical need for superior heart valve replacements for patients of all ages. Current valve substitutes provide excellent quality of life but have limited durability, mostly because these are non-living implants. The most physiologic valve replacements are considered the valve homografts, which have excellent hemodynamics, but lack cells. Therefore, the ideal valve substitute would be an in vitro regenerated, living construct which closely mimics the unique biological and hemodynamic features of the aortic root. The aortic root comprises distinct anatomical components, extracellular matrix molecules and cells, which maintain a balanced matrix homeostasis; the secret to life-long mechanical endurance. We hypothesized that functional aortic root regeneration in vitro is possible by seeding each anatomical component of xenogenic acellular roots with adult stem cells or pre-differentiated adult stem cells, and exposing cell-seeded roots to controlled mechanical cues to induce stem cell differentiation and maturation into target cells as a response to the "niche" biology and biomechanics. Proposed aims systematically approach testing this hypothesis by accomplishing internal and external seeding of acellular roots with cells, followed by progressive exposure to mechanical stimuli adaptation and dynamic conditioning, reaching aortic valve hemodynamic conditions. Pilot studies demonstrate feasibility of each proposed technique, including development of novel microarray-based seeding approaches, 3D rotators for adaptation and advanced valve bioreactors for conditioning. A multi-PI team of world renowned experts in each of the critical fields has been put together to ensure successful completion of the study. It is expected that such procedures will lead to mechanically robust, fully functional, viable aortic valve roots populated with metabolically active cells capable of matrix remodeling. This would ensure hemodynamic functionality immediately after implantation as well as long- term mechanical and biological stability due to continuous cell-mediated matrix repair. These replacement valves, developed with the aid of technologically advanced, integrated regeneration platforms would be ready for preclinical translational testing in large animals.