Engineered Human Heart Slice for Testing Drug-Induced Arrhythmia

新的标准正在制定中，用于心律失常风险药物的心脏安全性测试， 临床前目标是预测尖端扭转型室性心动过速（TdP）的风险。在美国， 促心律失常分析（CiPA）倡议已由政府监管机构、公私营 伙伴关系、工业界和学术界。该倡议的一个组成部分在于使用人类诱导的 多能干细胞衍生的心肌细胞（hiPSC-CM）作为药物反应的验证平台， 替代依赖于单离子通道（HERG）阻断的异源表达系统。如果通过， CiPA代表了使用含有主要离子通道的细胞进行药物测试的一个重大进步， 在人类心脏中发现的信号通路hiPSC-CM的这种应用是活跃的研究领域， 开发，许多合同研究组织和大多数制药公司已经成立 实验室使用这些细胞进行测试化合物的高通量筛选。然而，目前的hiPSC-CM 筛选往往是在单个或少数表现出不成熟和异质性的细胞上进行的。此外，本发明还提供了一种方法， 心律失常事件仅限于早期后除极（埃兹）或不规则搏动。TdP最终是 由折返性或多灶性异位活动引起的多细胞组织现象， 尺寸要显示出来。 本项目的目标是开发一种适用于测试药理学化合物的体外模型， 评估组织水平心律失常的风险。霍普金斯的三个研究实验室将为这项研究贡献他们的专业知识。 项目用于支持hiPSC-CM的组织平台将是在Tung的研究中开发的工程心脏切片。 心脏电生理实验室将实现生理功能改善的切片2.0版 使用经证实和推定的成熟刺激剂，然后用于检测药物诱导的折返性或多灶性 心律不齐为此，将通过Boheler实验室的专业知识来追求细胞的代谢成熟， 该研究将CD 36鉴定为细胞表面标志物，以区分代谢更成熟的细胞。一 在Kwon的心脏发育生物学实验室开发的生物信息学方法将用于跟踪 心肌细胞的成熟轨迹。这些技术的融合将带来一种先进的 体外组织模型，将用于独立和机械评估的promammic作用 选择已在临床上鉴定为低、中和高风险的化合物，并确定 心肌细胞的成熟状态是否影响它们的药物反应。这种方法代表了一种新的 心脏安全性测试的范例-这是一个更接近于预测TdP样心肌事件的范例。 心肌-并可能建立新的标准的效用，有效性和成熟依赖性的hiPSC-CM 作为评估心律失常风险的实验模型。

New standards are under development for cardiac safety testing of drugs for risk of arrhythmia, ultimately with the preclinical goal of predicting risk for Torsade de Pointes (TdP). In the U.S. the Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative has been advocated by government regulatory agencies, public-private partnerships, industry and academia. One component of the initiative rests on the usage of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) as a validation platform of drug responses that can replace heterologous expression systems which dwell on block of a single ion channel (HERG). If adopted by the FDA, CiPA represents a major step forward for drug testing using cells that contain the major ion channels and signaling pathways found in human heart. This application of hiPSC-CMs is an area of active research and development, and numerous contract research organizations and most pharmaceutical companies have founded labs to perform high throughput screening of test compounds using these cells. However, current hiPSC-CM screens tend to be on single or small numbers of cells that exhibit immaturity and heterogeneity. In addition, arrhythmic events are limited to early afterdepolarizations (EADs) or irregular beating. TdP is ultimately a multicellular tissue phenomenon that results from reentrant or multifocal ectopic activity that require a minimum size to be revealed. The goal of this project is to develop an in vitro model suitable for testing pharmacological compounds and assessing risk for tissue-level arrhythmia. Three research labs at Hopkins will contribute their expertise for the project. The tissue platform used to support the hiPSC-CMs will be the Engineered Heart Slice developed in Tung’s cardiac electrophysiology lab. Version 2.0 of the slice with improved physiological function will be implemented using proven and putative maturation stimulants, and then used to test for drug-induced reentrant or multifocal arrhythmia. To this end, metabolic maturation of the cells will be pursued via the expertise of the Boheler lab, which has identified CD36 as a cell surface marker distinguishing cells that are metabolically more mature. A bioinformatics approach developed in Kwon’s cardiac developmental biology lab will be used to follow the maturation trajectory of the cardiomyocytes. The convergence of these technologies will result in an advanced in vitro tissue model that will be used to independently and mechanistically assess the proarrhythmic effects of selected compounds which have been identified clinically as low, intermediate, and high risk, and to determine whether the maturation state of the cardiomyocytes affects their drug responses. This approach represents a new paradigm for cardiac safety testing – one that is a step closer to predicting TdP-like arrhythmic events in the myocardium – and may establish new standards for the utility, validity, and maturation-dependence of hiPSC-CMs as an experimental model to assess arrhythmia risk.