Tissue engineering of a differentiated cardiac muscle construct
Tissue engineering of a differentiated cardiac muscle construct
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DOI：
10.1161/hh0202.103644
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发表时间：
2002-02-08
影响因子：
20.1
通讯作者：
Eschenhagen, T
中科院分区：
文献类型：
--
作者：
Zimmermann, WH;Schneiderbanger, K;Eschenhagen, T
心脏组织工程是一个新兴领域。工程心脏组织（EHT）在体外和体内应用的适用性将取决于体外合胞体组织形成和心肌细胞分化的程度、收缩功能和电生理特性。在这里，我们证明，当新生大鼠的心肌细胞与胶原蛋白 I 和基质因子混合、铸入圆形模具中并进行阶段性机械拉伸时，会重建显示分化心肌重要特征的环形 EHT。对 EHT 与新生、6 日龄和成年大鼠天然心脏组织的比较组织学分析表明，EHT 中的心肌细胞重建了紧密互连、纵向定向的心肌束，其形态特征类似于成年而不是未成熟的天然组织。共聚焦和电子显微镜显示了天然分化心肌的特征；其中一些特征在新生大鼠的肌细胞中不存在：（1）高度组织化的肌节； (2)粘附连接、间隙连接和桥粒； (3) 发育良好的T管系统并与肌浆网形成二元体； (4)心肌细胞周围的基底膜。因此，EHT 显示出天然心肌的收缩特征，具有高抽搐（0.4 至 0.8 mN）与静息张力（0.1 至 0.3 mN）的比率以及强烈的 β 肾上腺素能正性肌力反应。动作电位记录显示 -66 至 -78 mV 的稳定静息膜电位、快速的上冲动力学和显着的平台期。数据表明，EHT 代表了高度分化的心脏组织结构，使 EHT 成为心脏功能和组织替代疗法体外研究的有前途的材料。
Cardiac tissue engineering is an emerging field. The suitability of engineered heart tissue (EHT) for both in vitro and in vivo applications will depend on the degree of syncytoid tissue formation and cardiac myocyte differentiation in vitro, contractile function, and electrophysiological properties. Here, we demonstrate that cardiac myocytes from neonatal rats, when mixed with collagen I and matrix factors, cast in circular molds, and subjected to phasic mechanical stretch, reconstitute ring-shaped EHTs that display important hallmarks of differentiated myocardium. Comparative histological analysis of EHTs with native heart tissue from newborn, 6-day-old, and adult rats revealed that cardiac cells in EHTs reconstitute intensively interconnected, longitudinally oriented, cardiac muscle bundles with morphological features resembling adult rather than immature native tissue. Confocal and electron microscopy demonstrated characteristic features of native differentiated myocardium; some of these features are absent in myocytes from newborn rats: (1) highly organized sarcomeres in registry; (2) adherens junctions, gap junctions, and desmosomes; (3) a well-developed T-tubular system and dyad formation with the sarcoplasmic reticulum; and (4) a basement membrane surrounding cardiac myocytes. Accordingly, EHTs displayed contractile characteristics of native myocardium with a high ratio of twitch (0.4 to 0.8 mN) to resting tension (0.1 to 0.3 mN) and a strong beta-adrenergic inotropic response. Action potential recordings demonstrated stable resting membrane potentials of -66 to -78 mV, fast upstroke kinetics, and a prominent plateau phase. The data indicate that EHTs represent highly differentiated cardiac tissue constructs, making EHTs a promising material for in vitro studies of cardiac function and tissue replacement therapy.