Electrophysiological maturation and integration of murine fetal cardiomyocytes after transplantation
Electrophysiological maturation and integration of murine fetal cardiomyocytes after transplantation
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DOI：
10.1161/circresaha.107.153643
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发表时间：
2007-08-31
影响因子：
20.1
通讯作者：
Mueller-Ehmsen, Jochen
中科院分区：
文献类型：
--
作者：
Halbach, Marcel;Pfannkuche, Kurt;Mueller-Ehmsen, Jochen
在本研究中，我们研究了移植后未成熟心肌细胞的电生理成熟和整合；成熟和整合是实现心脏再生的关键。将α-肌动蛋白启动子控制下表达增强型绿色荧光蛋白的小鼠胚胎心肌细胞(d12.5-d15.5)注射到冷冻损伤的小鼠心室肌损伤区域和邻近心肌中。移植后5~6天取存活的脑室短轴组织片(厚150微米)。用玻璃微电极测量移植的FCM和切片内宿主心肌细胞的动作电位。通过放置在可存活宿主组织中的单极电极，以高达10赫兹的频率进行刺激。与成年心肌细胞相比，移植的FCM的绿色荧光和电生理特性可明显区别于宿主组织：最大上搏速度(V-max)显著降低，复极50%动作电位时程(APD50)显著延长。移植的FCM在冷冻损伤的组织周围表现出自发的电活动和收缩活动，这种活动与宿主组织完全不同步。这些未整合细胞的V-max和apd(50)与培养的游离FCM相匹配。相反，82%的移植FCM被可存活的宿主组织包围，即电和收缩活动与宿主组织同步，这些细胞具有更成熟的动作电位参数(显著高于未整合的FCM的V-max和更短的APD50)。总之，移植的FCM的电生理成熟和整合依赖于在存活的宿主心肌中的植入。被冷冻损伤的组织包围的FCM保持生理但不成熟的AP特性。
In the present study, we investigated the electrophysiological maturation and integration of immature cardiomyocytes after transplantation; maturation and integration are essential to achieve the cardiac regeneration. Murine fetal cardiomyocytes (FCMs) (d12.5-d15.5) expressing enhanced green fluorescent protein under the control of the alpha-actin promoter were injected into cryoinjured areas and adjacent myocardium of cryoinjured mouse ventricles. Viable short axis tissue slices (thickness, 150 mu m) of the ventricles were prepared 5 to 6 days after transplantation. Glass microelectrodes were used for measurements of action potentials in transplanted FCMs and host cardiomyocytes within the slices. Stimulation at frequencies of up to 10 Hz was performed via a unipolar electrode placed in viable host tissue. Transplanted FCMs could be distinguished clearly from host tissue by their green fluorescence and their electrophysiological properties: maximal upstroke velocity (V-max) was significantly lower and action potential duration at 50% repolarization (APD(50)) was significantly longer compared with values of adult cardiomyocytes. Transplanted FCMs surrounded by cryoinjured tissue showed spontaneous electrical and contractile activity, which was in no case synchronous with host tissue. V-max and APD(50) of these nonintegrated cells matched values of cultivated dissociated FCMs. In contrast, 82% of transplanted FCMs surrounded by viable host tissue were electrically integrated; ie, electrical and contractile activity was synchronous with host tissue and these cells had more mature action potential parameters (significantly higher V-max and shorter APD(50)) compared with nonintegrated FCMs. In conclusion, electrophysiological maturation and integration of transplanted FCMs depend on an embedment in viable host myocardium. FCMs surrounded by cryoinjured tissue maintain physiological but immature AP properties.