Engineering Functional Cardiac Tissue Chambers

描述：一个多世纪以来，心脏病一直是西方世界面临的最具破坏性的卫生保健问题之一，也是美国的头号杀手。由于心肌自我修复的能力似乎是最小的，心脏病患者往往会留下永久性损伤，损害泵功能，恶化为慢性心力衰竭。仅在美国，2006年心脏病的相关经济成本预计将超过2500亿美元。因此，最近人们对以细胞为基础的替代、修复或再生受损心肌的新方法感到非常兴奋。然而，这种策略的实际益处被不一致的结果和非常低的移植细胞存活率所掩盖。由于缺乏对所涉及的潜在机制的控制和理解，这些技术的成功受到了限制。这部分是由于现有实验方法中缺少一个环节。培养皿中的成功并不能保证转化为动物模型，动物模型中的测试通常涉及如此复杂的因素组合，以至于很难解释结果。心肌生理学研究的一个核心方法是使用分离的器官或组织制剂。然而，存活能力仅限于几个小时或几天，这不足以测试长期的愈合反应。显然，对心脏病和修复机制的理解将受益于一个简化的心脏模型，该模型可以在组织培养实验室中创建，用于高通量体外测试。因此，本提案的总体目标是利用组织工程原理创造第一个简化的心腔或心脏类器官，它具有心室泵功能的基本特征，可以作为理想的替代心脏，在体外有效地评估新的治疗策略。通过允许独立控制室的几何形状、组织组成、循环生化因子和机械负荷条件，该系统将提供前所未有的能力来研究调节心肌生态位环境的影响。与传统的心脏贴片或心脏贴片不同，这种工程化的组织腔体可以直接测量压力和容积之间的相关功能关系，从而最终将心脏定性为一个泵。本建议的主要方面被认为是探索性和发展性的，符合R21筹资机制的目标。总体目标将实现以下具体目标：目标1：开发一种多功能高通量集成生物反应器系统，用于工程心脏组织腔室的创建，刺激和评估。目的2：测试机械和生化因素对工程心脏组织腔（ETCH）关键结构、功能和分子特征的影响。特别是，我们将在ETCH共培养中测试壁应力调节人间充质前体细胞和新生大鼠心肌细胞之间相互作用的假设。

DESCRIPTION: For more than a century, heart disease has been one of the most devastating health care issues facing the Western world, and is the single leading killer in America. Because the capacity for cardiac muscle to repair itself appears to be minimal at best, cardiac patients are often left with permanent damage that compromises pump function and deteriorates to a chronic state of heart failure. The associated economic cost of heart disease in the US alone is expected to exceed $250 billion dollars in 2006. Therefore, there has recently been tremendous excitement about novel cell-based approaches for replacing, repairing or regenerating damaged myocardium. However, the practical benefit of such strategies has been obscured by inconsistent results and very low survival rates of implanted cell grafts. The success of these techniques has been limited by a lack of control and understanding of the underlying mechanisms involved. This is partly due to a missing link in the available experimental methods. Success in the petri dish does not ensure translation to the animal model, and testing in animal models often involves such a complex combination of factors that it is difficult to interpret the outcomes. One approach that has been central to the study of cardiac muscle physiology is the use of isolated organ or tissue preparations. However, viability is limited to a few hours or days at best, which is insufficient to test a long term healing response. Clearly, the understanding of heart disease and mechanisms of repair would benefit from a simplified heart model that could be created in a tissue culture laboratory for high throughput in vitro testing. Therefore, the overall objective of this proposal is to use the principles of tissue engineering to create the first simplified heart chamber, or cardiac organoid, that exhibits the essential characteristics of ventricular pump function and can serve as an idealized surrogate heart for efficient evaluation of novel therapeutic strategies in vitro. By allowing independent control of chamber geometry, tissue composition, circulating biochemical factors, and mechanical loading conditions, this system would offer an unprecedented ability to study the effects of modulating a myocardial niche environment. Unlike more traditional cardiac patches or strips, the engineered tissue chamber would allow direct measurement of relevant functional relationships between pressure and volume that ultimately characterize the heart as a pump. Key aspects of this proposal are considered to be exploratory and developmental in nature, consistent with the objectives of the R21 funding mechanism. The overall objective will be achieved with the following specific aims: Aim 1: To develop a versatile high-throughput integrated bioreactor system for the creation, stimulation, and evaluation of engineered cardiac tissue chambers. Aim 2: To test the effects of mechanical and biochemical factors on the key structural, functional, and molecular features of engineered cardiac tissue chambers (ETCH). In particular we will test the hypothesis that wall stress modulates the interaction between human mesenchymal precursor cells and neonatal rat cardiac myocytes in ETCH co-cultures.