Toward Regeneration of Whole Bioartificial Human Heart

描述(申请人提供)：心脏病是美国的主要死因。心肌梗死(MI)影响着8000多万美国人，约500万美国人患有心力衰竭，心力衰竭以每年约50万新发病例的速度增加。由于心脏再生能力有限，终末期心力衰竭是不可逆转的，心肌梗死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，由于可供移植的供体心脏有限，每年约有50,000人死亡。心脏组织工程为心脏疾病的未来治疗提供了在体外制造心脏组织的可能性，如心脏瓣膜置换、心肌移植、药物筛选以及用于移植的工程功能完整心脏。心脏组织工程需要心血管细胞和三维(3D)支架。工程心脏组织的一般策略是通过将功能非人类心脏细胞(如跳动的新生小鼠CMS和血管细胞)与生物材料基质混合实现的。已经利用了各种合成和自然派生的矩阵。然而，大多数合成基质存在生物相容性问题，不能保持与天然心脏细胞外基质(ECM)相同的三维结构、复杂组成和微生态位，ECM具有支持心脏形成和维持心脏功能的功能。此外，由于人类心脏细胞的可获得性有限，人类心脏组织工程在很大程度上仍处于不发达状态。最近，我们开发了一种新的重建人类心脏结构的策略，即用来自人诱导的多潜能干细胞(IPS)的多潜能心血管祖细胞(MCP)对整个无细胞小鼠心脏进行再细胞改造。MCPS代表了人类心脏发生过程中最早的心脏祖细胞。将MCPs原位分化为心肌细胞(CMS)、血管内皮细胞(ECs)和平滑肌细胞(SMC)，再接种于脱细胞小鼠心脏，可重建脱细胞小鼠心脏。工程心脏结构显示肌肉和血管样结构，以每分钟40-50次的速度自发收缩，显示细胞内钙瞬变，并对各种药物干预做出预期反应。因此，我们的研究建立了一种新的策略，可以用于使用患者特定的iPS细胞来再生个性化的人类心脏组织和整个心脏。这项提议的中心目的是测试人诱导性多能干细胞来源的MCP是否可以用于重新填充完整的无细胞人类心脏支架，以重建完整的生物人工心脏。此外，我们将研究人类心脏ECM对重新接种的人MCP的CM承诺的影响。这一建议的结果将对未来人类心脏病的翻译治疗具有重要意义。

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.