Spatial complexity of cardiac cell culture and spatial-temporal bioelectric activity: granularity and mechanical-electrical feedback.

该研究旨在了解培养的干细胞衍生的心肌细胞（SC-CM）的生物电和生物力学特性之间的联系及其对自发电活动的作用。衍生单细胞膜是一组复杂且异质的连接细胞。从干细胞获得的富集的SC-CM是浓缩的心肌细胞样细胞，其具有不均匀的生物电特性，当以单层培养时，导致可兴奋细胞的多细胞连接网。该研究计划将有助于更好地了解细胞群体异质性的影响，电刺激和机械变形对生物电特性和时空多细胞自组织的作用。为了实现这一目标，该方案分为三个部分。 1-基于SC-CM培养自发节律的具有反馈过程的成像系统的开发。我们正在开发一种培养和监测心肌样细胞分化过程中收缩活动的方法。这种“芯片上”培养方法提供了一个稳定和连续的工程干细胞衍生的心脏组织的评价。广泛的可用帧速率和图像分辨率证明了我们的系统的适应性。因此，可以评估细胞分布以及功能特性。将增加一个基于收缩率和收缩异质性的反馈过程。将研究不同类型的电刺激方案对自发活动的反馈效应的评价。 2-研究单层心肌细胞自发节律的时空异质性。使用我们的集成培养成像系统，我们的目标是研究SC-CMs单层形成的时间依赖性过程和自发活动的异质性。干细胞在单层中的分化是一个随机过程，因此异质群体如何分布在单层中是未知的。为了更好地理解这一过程，我们还将比较，与我们的数学模型，异质细胞分布和分散的固有频率的自主电活动的电自组织的作用。 3-评价机械-电反馈对SC-CM单层自发活动的影响。我们已经开发了一个拉伸装置来研究机械变形对时空电活动的影响。急性拉伸对SC-CM单层时空活动的影响仍然未知。两种被称为时钟的机制（电压和钙）可以在自发活动中发挥核心作用。将使用荧光绘图研究拉伸下自发活动的重要性。 SC-CM工程组织动力学的高度复杂性需要整合这些创新方法和技术，以揭示发生的多尺度变化和对电活动的功能影响。

The study is aimed at understanding the link between the bioelectrical and biomechanical properties of cultured stem-cell derived cardiomyocytes (SC-CMs) and their role on spontaneous electrical activity. Derived monolayers are complex and heterogeneous set of connected cells. Enriched SC-CMs obtained from stem cells are concentrated cardiomyocytes-like cells with heterogeneous bioelectrical properties leading to a multi-cellular connected mesh of excitable cells when cultured in monolayers. The research program will help better understand the effects of cell population heterogeneity, the role of electrical stimulation and mechanical deformation on bioelectric characteristics and spatial-temporal multicellular self-organization. To achieve this goal, the program has been divided in three parts. 1- Development of an imaging system with feedback process based on spontaneous rhythm of SC-CMs culture. We are developing an approach for culture and monitoring of contractile activity during differentiation of cardiomyocyte-like cells. This “on-chip” culture approach offers a stable and continuous evaluation of engineered stem cells-derived cardiac tissue. The wide range of available frame rates and image resolutions demonstrates the adaptability of our system. Therefore, cell distribution can be evaluated as well as functional characteristics. A feedback process based on the rate and heterogeneity of contraction will be added. An evaluation of the feedback effects on spontaneous activity of different type of electrical stimulation protocol will be studied. 2- Study the spatial-temporal heterogeneity in spontaneous rhythm of derived cardiomyocytes in monolayers. Using our integrated culture-imaging system we aim to study the time-dependent process of SC-CMs monolayer formation and heterogeneity of spontaneous activity. Stem cell differentiation in monolayers is a stochastic process such that how heterogeneous populations are distributed within the monolayer is unknown. To better understand this process, we will also compare, with our mathematical models, the role of heterogeneous cell distribution and dispersion of intrinsic frequencies of autonomous electrical activity on electrical self-organization. 3- Evaluate the effects of mechanical-electrical feedback on the spontaneous activity of SC-CMs monolayers. We have developed a stretching apparatus to study the effects of mechanical deformation on spatial-temporal electrical activity. The acute effects of stretch on SC-CM monolayer spatial-temporal activity remain unknown. Two mechanisms known as clocks (voltage and calcium) could play a central role on spontaneous activity. The importance on spontaneous activity under stretch will be studied using fluorescence mapping. The high level of complexity of SC-CM engineered tissue dynamics needs integration of these innovative approaches and techniques to uncover the multiscale changes occurring and the functional impact on electrical activity.