CAREER:Tissue-engineering an aging heart: The effect of aged cell microenvironment in myocardial infarction

大多数致命疾病，特别是心血管疾病，更多地发生在老年人身上，年龄是主要的危险因素。因此，迫切需要更好地了解衰老组织的疾病进展，以便找到减少与年龄相关的问题的方法。本项目旨在建立一种独特的人体衰老心肌组织工程模型系统，用于研究衰老组织微环境对心肌梗死后细胞存活的影响。新模型克服了1)动物模型对人类条件适用性有限且涉及复杂系统且难以控制参数的局限性，2)细胞培养模型过于简化的局限性。研究旨在验证衰老组织微环境（即细胞外基质（ECM）的硬度等生化成分和生物物理特性）影响心肌梗死后细胞存活的假设，以及细胞损伤导致的细胞通讯减少是衰老组织中细胞死亡增加的原因。通过本科生和研究生的培训和指导活动，以及为期三天的名为“通过科学实现和平”的夏季讲习班，将研究和教育结合起来，该讲习班旨在利用科学来教授宽容和包容。作为长期职业目标的一部分，建立一个专注于仿生工程模型组织的研究项目，以研究健康和病变组织中的多细胞通信和细胞-微环境相互作用。这个项目的重点是首次研究证明组织工程和微加工可以创建高度有效的模拟衰老的疾病模型，这些模型可以用来阐明衰老在特定疾病——心肌梗死中的作用。需要验证的具体假设有：1)基质年龄会影响细胞存活，这是由于年龄改变了生化和生物物理基质含量；2)细胞的实足年龄会影响细胞存活，这是由于细胞分泌的旁分泌因子随着年龄的变化而改变；3)心肌组织中随着年龄积累的细胞损伤会导致细胞功能和相互作用下降，导致老年组织心肌梗死时细胞死亡增加。相关的研究目标是：1)创建可用于模拟心肌梗死条件的衰老模拟心肌模型组织；2)研究衰老组织微环境对心肌梗死细胞存活的影响。工程心肌组织模型将使用人诱导多能干细胞衍生的内皮细胞和心肌细胞、仿生水凝胶和微流体进行微制备。细胞通讯将在mi模拟条件下（即缺氧，营养饥饿，再灌注和氧化应激）进行研究。利用该模型组织获得的知识将揭示正常、衰老和病变心肌的细胞通讯，并将阐明心肌梗死的细胞水平现象和衰老本身的本质。由于在动物模型中只有10%的治疗方法通过临床试验，使用人类细胞的工程组织模型由于其优于动物模型的优势以及通过填补体外和体内研究之间的空白来增加基础科学临床转化的潜力而受到广泛关注。

PI: Zorlutuna, PinarProposal #: 1651385Most deadly diseases, and particularly cardiovascular diseases, occur more often in older people, with age being the primary risk factor. Therefore, an urgent need exists for a better understanding of disease progress in aged tissues in order to find ways to decrease age-related problems. This project focuses on establishing a unique tissue engineered model system of the aging human myocardium that can be used to investigate the role of the aging tissue microenvironment on cell survival after a heart attack/myocardial infarction (MI). The novel model overcomes limitations 1) of animal models that have limited applicability to the human condition and involve complex systems with difficult to control parameters and 2) of cell culture models that are oversimplified. Studies are designed to test the hypothesis that the aging tissue microenvironment (i.e., biochemical composition and biophysical properties such as stiffness of the extracellular matrix (ECM)) affects cell survival after MI, and the decreased cellular communication due to cellular damage is the cause of increased cell death in older tissues. Research and education are integrated through undergraduate and graduate training and mentoring activities and a three-day summer workshop titled "Peace through Science" that aims to leverage science to teach tolerance and inclusion.As part of the long-term career goal to establish a research program focused on biomimetic engineered model tissues to investigate the multicellular communication and cell-microenvironment interactions in healthy and diseased tissues, the focus of this project is the first study to demonstrate that tissue engineering and microfabrication can create highly impactful aging-mimicking disease models and that these models can be used to elucidate the role of aging on a specific disease--myocardial infarction. Specific hypotheses to be tested are: 1) matrix age affects cell survival due to altered biochemical and biophysical matrix content by age, 2) chronological age of cells affects cell survival due to altered paracrine factor secretion by the cells by age and 3) cellular damage that accumulates by age in myocardial tissue causes decreased cellular function and interaction, resulting in increased cell death upon MI in older tissues. The related research objectives are to 1) create an aging mimicking myocardial model tissue that can be used to simulate MI conditions and 2) study the effect of the aging tissue microenvironment on cell survival upon MI. The engineered myocardial tissue model will be microfabricated using human induced pluripotent stem cell-derived endothelial and myocardial cells, biomimetic hydrogels and microfluidics. Cellular communication will be studied under MI-mimicking conditions (i.e., hypoxia, nutrient starvation, reperfusion and oxidative stress.) The knowledge gained using this model tissue will unravel the cellular communication within normal, aging and diseased myocardium and will shed light on both the cell-level phenomena upon MI and on the nature of aging itself. As only 10% of therapies that are shown to be successful in animal models pass clinical trials, engineered tissue models using human cells are gaining much interest due to their advantages over animal models and their potential to increase clinical translation of basic science by filling the gap between in vitro and in vivo studies.