Native cardiac tissue is composed of heterogeneous cell populations that work cooperatively for proper tissue function; thus, engineered tissue models have moved toward incorporating multiple cardiac cell types in an effort to recapitulate native multicellular composition and organization. Cardiac tissue models composed of stem cell-derived cardiomyocytes (CMs) require inclusion of non-myocytes to promote stable tissue formation, yet the specific contributions of the supporting non-myocyte population on the parenchymal CMs and cardiac microtissues have to be fully dissected. This gap can be partly attributed to limitations in technologies able to accurately study the individual cellular structure and function that comprise intact three-dimensional (3D) tissues. The ability to interrogate the cell-cell interactions in 3D tissue constructs has been restricted by conventional optical imaging techniques that fail to adequately penetrate multicellular microtissues with sufficient spatial resolution. Light sheet fluorescence microscopy (LSFM) overcomes these constraints to enable single-cell resolution structural and functional imaging of intact cardiac microtissues. Multicellular spatial distribution analysis of heterotypic cardiac cell populations revealed that CMs and cardiac fibroblasts were randomly distributed throughout 3D microtissues. Furthermore, calcium imaging of live cardiac microtissues enabled single-cell detection of CM calcium activity, which showed that functional heterogeneity correlated with spatial location within the tissues. This study demonstrates that LSFM can be utilized to determine single-cell spatial and functional interactions of multiple cell types within intact 3D engineered microtissues, thereby facilitating the determination of structure-function relationships at both tissue-level and single-cell resolution. Impact statement The ability to achieve single-cell resolution by advanced three-dimensional light imaging techniques enables exquisite new investigation of multicellular analyses in native and engineered tissues. In this study, light sheet fluorescence microscopy was used to define structure-function relationships of distinct cell types in engineered cardiac microtissues by determining heterotypic cell distributions and interactions throughout the tissues as well as by assessing regional differences in calcium handing functional properties at the individual cardiomyocyte level.

中文翻译：

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使用光片显微镜单细胞测定心脏微组织的结构和功能。

天然心脏组织由异种细胞群体组成，这些细胞群体协同工作以实现适当的组织功能。因此，工程组织模型已朝着整合多种心脏细胞类型的方向努力，以概括天然的多细胞组成和组织。由干细胞衍生的心肌细胞（CM）组成的心脏组织模型需要包含非心肌细胞以促进稳定的组织形成，但是必须完全解剖支持的非心肌细胞群体对实质CM和心脏微组织的特定作用。这种差距可以部分归因于能够准确研究组成完整三维（3D）组织的单个细胞结构和功能的技术限制。询问3D组织构造中细胞间相互作用的能力已受到常规光学成像技术的限制，该技术无法以足够的空间分辨率充分穿透多细胞微组织。光片荧光显微镜（LSFM）克服了这些限制，可以对完整的心脏显微组织进行单细胞分辨率的结构和功能成像。对异型心脏细胞群体的多细胞空间分布分析表明，CM和心脏成纤维细胞随机分布在整个3D微组织中。此外，活体心脏微组织的钙成像使CM钙活性的单细胞检测成为可能，这表明功能异质性与组织内的空间位置相关。这项研究表明，LSFM可用于确定完整的3D工程微组织内多种细胞类型的单细胞空间和功能相互作用，从而有助于在组织水平和单细胞分辨率上确定结构-功能关系。影响陈述通过先进的三维光成像技术实现单细胞分辨率的能力，可以对天然和工程组织中的多细胞分析进行精妙的新研究。在这个研究中，