Toward Regeneration of Whole Bioartificial Human Heart

描述（由申请人提供）：心脏病是美国的主要死亡原因。心肌梗塞（MI）影响超过8000万美国人，并且大约500万美国人患有心力衰竭，心力衰竭以每年约500，000例新病例的速度增加。由于心脏再生能力有限，终末期心力衰竭是不可逆的，MI患者的心功能不能自发恢复。心脏移植是终末期心力衰竭患者的最终治疗策略。然而，每年约有50，000人因可供移植的供体心脏有限而死亡。心脏组织工程为将来的心脏病治疗提供了离体心脏组织，如心脏瓣膜置换、心肌植入、药物筛选以及用于移植的功能性全心脏。心脏组织工程需要心血管细胞和三维支架材料。工程心脏组织的一般策略是通过将功能性非人类心脏细胞（例如跳动的新生小鼠CM和血管细胞）与生物材料基质混合来实现。已经使用了各种合成和天然衍生的基质。然而，大多数合成基质具有生物相容性问题，并且不保留与天然心脏中的细胞外基质（ECM）相同的3D结构、复杂组成和微生态位，其功能是支持心脏形成和维持心脏功能。此外，由于人类心脏细胞的有限可用性，人类心脏组织工程在很大程度上仍然不发达。最近，我们开发了一种新的策略，重建人类心脏结构的再细胞化整个脱细胞小鼠心脏与多能心血管祖细胞（MCP）来自人诱导多能干细胞（iPS）。MCP代表人类心脏发生中最早的人类心脏祖细胞。将MCP移植到去细胞小鼠心脏中，原位高效分化为心肌细胞（CMs）、平滑肌细胞（SMCs）和内皮细胞（ECs），重建去细胞小鼠心脏。工程化的心脏结构表现出肌肉和血管样结构，以每分钟40-50次心跳的速率自发收缩，表现出细胞内Ca 2+瞬变，并对各种药物干预产生预期的反应。因此，我们的研究建立了一种新的策略，可用于使用患者特异性iPS细胞再生个性化的人类心脏组织以及整个心脏。该提议的中心目的是测试人iPS细胞衍生的MCP是否可用于重新填充整个脱细胞人心脏支架以重建整个生物人工人心脏。此外，我们将研究人类心脏ECM对来自恢复的人类MCP的CM承诺的影响。本研究的结果对人类心脏病的转化治疗具有重要意义。

DESCRIPTION (provided by applicant): Heart disease is the leading death cause in the United States. Myocardial infarction (MI) affects over 80 million American people and approximately 5 million Americans are living with heart failure, which increases with an annual rate of about 500,000 new cases. Given the limited regenerative capability of heart, end stage heart failure is irreversible and heart function of MI patients cannot be spontaneously recovered. Heart transplantation is the ultimate treatment strategy for end stage heart failure patients. However, approximately 50,000 people die each year due to the limited availability of donor hearts for transplant. Heart tissue engineering offers the potential of making cardiac tissues ex vivo for future therapy of heart disease, such as for replacement of cardiac valves, myocardium implantation, drug screening, as well as engineering functional whole heart for transplantation. Heart tissue engineering requires a resource of cardiovascular cells and three dimensional (3D) scaffolds. The general strategy of engineering heart tissue is achieved by mixing functional non-human heart cells, such as beating neonatal mouse CMs and vascular cells, with biomaterial matrices. A variety of synthetic and natural derived matrices have been utilized. However, most of the synthetic matrices have biocompatibility problems and do not preserve the same 3D architectures, complex compositions and micro-niches as the extracellular matrix (ECM) in native heart, which functions to support heart formation and maintain heart function. In addition, due to the limited availability of human heart cells, human heart tissue engineering has been largely remained underdeveloped. Recently we developed a novel strategy for rebuilding human heart constructs by recellularizing whole acellular mouse hearts with multipotential cardiovascular progenitors (MCPs) derived from human induced pluripotent stem (iPS) cells. MCPs represent the earliest human heart progenitors in human cardiogenesis. When reseeded into acellular mouse hearts, MCPs in situ differentiated into cardiomyocytes (CMs), smooth muscle cells (SMCs) and endothelial cells (ECs) with high efficiency, which reconstructed the decellularized mouse hearts. The engineered heart constructs exhibited muscle and vessel-like structures, contracted spontaneously with a rate of 40-50 beats per min, exhibited intracellular Ca2+ transients and responded as expected to various drug interventions. Therefore our study established a novel strategy, which could be used to regenerate personalized human heart tissues as well as whole hearts using patient-specific iPS cells. The central aim of this proposal is to test whether human iPS cell- derived MCPs could be used to repopulate whole acellular human heart scaffolds for rebuilding whole bioartificial human hearts. In addition, we will examine the impact of human heart ECMs on CM commitment from reseeded human MCPs. Outcome of this proposal will be significant for the future translational therapy of human heart disease.