The use of stem cells in generating cell-based pacemaker therapies for bradyarrhythmia is currently being considered. Due to the propensity of stem cells to form tumors, as well as ethical issues surrounding their use, the seed cells used in cardiac biological pacemakers have limitations. Very small embryonic-like stem cells (VSELs) are a unique and rare adult stem cell population, which have the same structural, genetic, biochemical, and functional characteristics as embryonic stem cells without the ethical controversy. In this study, we investigated the ability of rat bone marrow- (BM-) derived VSELs to differentiate in vitro into cardiomyocytes by 5-Azacytidine (5-AzaC) treatment. The morphology of VSELs treated with 10 μM 5-AzaC increased in volume and gradually changed to cardiomyocyte-like morphology without massive cell death. Additionally, mRNA expression of the cardiomyocyte markers cardiac troponin-T (cTnT) and α-sarcomeric actin (α-actin) was significantly upregulated after 5-AzaC treatment. Conversely, stem cell markers such as Nanog, Oct-4, and Sox2 were continuously downregulated posttreatment. On day 14 post-5-AzaC treatment, the positive expression rates of cTnT and α-actin were and , respectively. Taken together, our results showed that rat BM-VSELs have the ability to differentiate into cardiomyocytes in vitro. These findings suggest that VSELs would be useful as seed cells in exploring the mechanism of biological pacemaker activity.

中文翻译：

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5-氮杂胞苷诱导的非常小的胚胎样干细胞分化为心肌细胞。

目前正在考虑在产生基于细胞的起搏器性心律失常的起搏器疗法中使用干细胞。由于干细胞倾向于形成肿瘤，以及围绕其使用的伦理问题，用于心脏生物起搏器的种子细胞具有局限性。很小的类胚胎干细胞（VSEL）是独特且稀有的成年干细胞群体，与胚胎干细胞具有相同的结构，遗传，生化和功能特征，而没有伦理争议。在这项研究中，我们研究了大鼠骨髓（BM-）衍生的VSEL通过5-氮杂胞苷（5-AzaC）处理在体外分化为心肌细胞的能力。VSEL的形态用10处理 μM 5-AzaC的体积增加，并逐渐变为心肌样细胞形态，而没有大量细胞死亡。另外，在5-AzaC处理后，心肌细胞标志物心肌肌钙蛋白-T（cTnT）和α-肌节肌动蛋白（α-肌动蛋白）的mRNA表达被显着上调。相反，干细胞标记物（例如Nanog，Oct-4和Sox2）在后处理中不断下调。5-AzaC处理后第14天，cTnT和α-肌动蛋白的阳性表达率为 和 ，分别。两者合计，我们的结果表明，大鼠BM-VSEL具有体外分化为心肌细胞的能力。这些发现表明，VSEL作为种子细胞可用于探索生物起搏器活性的机制。