| Project/Area Number |
16590676
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | Nagoya University |
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Principal Investigator |
LEE Jong-Kook Nagoya University, Research Institute of Environmental Medicine, Associate Professor, 環境医学研究所, 助教授 (60303608)
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| Co-Investigator(Kenkyū-buntansha) |
HIDAKA Kyoko National Cardiovascular Center Research Institute, Department of Bioscience, バイオサイエンス部, 室長 (00216681)
MORISAKI Takayuki National Cardiovascular Center Research Institute, Department of Bioscience, バイオサイエンス部, 部長 (30174410)
KODAMA Itsuo Nagoya University, Research Institute of Environmental Medicine, Professor, 環境医学研究所, 教授 (30124720)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2004: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | ES cell / biological pacemaker / regenerated myocardium / bradyarrhythmias / gap junction / teratomas / 再生医学 / 胚性幹(ES)細胞 |
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| Research Abstract |
Nkx2.5-GFP knock-in murine ES cells were established by inserting GFP into Nkx2.5 allele. Embryoid bodies obtained with "hanging-drop" method were dispersed on day 10, and GFP-positive cells were isolated as ES cell-derived cardiac myocytes (ESCMs) using a fluorescence activated cell sorter (Hidaka et al. FASEB J 2003). Complete AV block (AVB) was created in mice by injecting PBS containing 10-20% glycerol into the AV nodal region. Five days after the operation, ESCMs (2×10^5) were injected into the AV nodal region. ECGs were continuously monitored with a telemetry system for 10 days. Expression of gap junctions was estimated by immunohistochemistry for connexin43 and 40 (Cx43/Cx40). AVB mice injected with PBS alone were used as references. The mice injected with PBS alone showed complete AVB throughout the entire observation period (HR:168±10 bpm, n=5). In contrast, four out of five mice injected with ESCMs restored AV conduction after the injection (HR:683±50 bpm, n=4). Ectopic pacemaker activity such as accelerated junctional rhythm was not observed in the ESCMs-transplanted mice after the cell transplantation. In the non-transplanted mice injected with PBS alone, marked fibrosis and discontinuity of Cx43/Cx40 expression were observed in the AV nodal region, whereas in the mice injected with ESCMs, substantial amounts of immunolabeled Cx43/Cx40 were recognized between ESCMs and the host cardiac myocytes. Transplantation of ESCMs restored the AV conduction in the mouse heart with surgically created complete AVB. Targeted local injection of ESCMs could be a novel therapeutic approach to treat life-threatening bradyarrhythmias.
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