Department of Cardiovascular Control, Kochi Medical School, Nankoku, Japan.
PLoS One. 2010 Feb 17;5(2):e9275. doi: 10.1371/journal.pone.0009275.
Understanding the basic mechanisms and prevention of any disease pattern lies mainly on development of a successful experimental model. Recently, engineered heart tissue (EHT) has been demonstrated to be a useful tool in experimental transplantation. Here, we demonstrate a novel function for the spontaneously contracting EHT as an experimental model in studying the acute ischemia-induced changes in vitro.
METHODOLOGY/PRINCIPAL FINDINGS: EHT was constructed by mixing cardiomyocytes isolated from the neonatal rats and cultured in a ring-shaped scaffold for five days. This was followed by mechanical stretching of the EHT for another one week under incubation. Fully developed EHT was subjected to hypoxia with 1% O(2) for 6 hours after treating them with cell protective agents such as cyclosporine A (CsA) and acetylcholine (ACh). During culture, EHT started to show spontaneous contractions that became more synchronous following mechanical stretching. This was confirmed by the increased expression of gap junctional protein connexin 43 and improved action potential recordings using an optical mapping system after mechanical stretching. When subjected to hypoxia, EHT demonstrated conduction defects, dephosphorylation of connexin-43, and down-regulation of cell survival proteins identical to the adult heart. These effects were inhibited by treating the EHT with cell protective agents.
CONCLUSIONS/SIGNIFICANCE: Under hypoxic conditions, the EHT responds similarly to the adult myocardium, thus making EHT a promising material for the study of cardiac functions in vitro.
了解任何疾病模式的基本机制和预防主要依赖于成功的实验模型的开发。最近，工程心脏组织 (EHT) 已被证明是实验移植的有用工具。在这里，我们展示了自发收缩的 EHT 在体外研究急性缺血诱导变化的新功能。
方法/主要发现：EHT 通过混合从新生大鼠中分离的心肌细胞并在环形支架中培养五天来构建。然后在孵育下对 EHT 进行另一个为期一周的机械拉伸。在用细胞保护剂如环孢素 A (CsA) 和乙酰胆碱 (ACh) 处理后，将完全发育的 EHT 置于 1% O(2) 下缺氧 6 小时。在培养过程中，EHT 开始显示自发性收缩，机械拉伸后收缩变得更加同步。这通过机械拉伸后间隙连接蛋白 connexin 43 的表达增加和使用光学映射系统记录的动作电位得到证实。在缺氧条件下，EHT 表现出与成年心脏相同的传导缺陷、连接蛋白-43 的去磷酸化和细胞存活蛋白的下调。这些作用可以通过用细胞保护剂处理 EHT 来抑制。
结论/意义：在缺氧条件下，EHT 对成年心肌的反应相似，因此 EHT 是研究体外心脏功能的有前途的材料。
