収縮性準備とカルシウム調節は,慢性的に負荷のない心臓からの筋細胞で低下しています
Kenta Ito1, Masaharu Nakayama, Faisal Hasan
1Department of Medicine, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, MA 02215, USA.
Circulation
|March 5, 2003
まとめ
慢性的な心臓の解荷は左心室 (LV) 質量を減少させ,時間とともに肌細胞の収縮機能を損なう. これは,長期にわたる心筋縮を伴う状態における潜在的パフォーマンスの欠陥を示唆しています.
科学分野:
- 心臓病学 心臓病学
- 生理学 生理学とは
- 細胞生物学 細胞生物学
背景:
- 慢性的な心臓の解荷は,左心室 (LV) 質量の減少につながります.
- 筋細胞の収縮機能に対する脱荷の影響は,依然としてほとんど不明である.
研究 の 目的:
- 慢性的な心不全が左心室筋細胞の収縮機能とカルシウム処理に及ぼす影響を調査する.
- 無負荷の心筋細胞における機能的変化の時間経過を決定する.
主な方法:
- ヘテロトピック心臓移植は,同位性のラットで心臓の放電を誘導するために使用されました.
- 筋細胞の収縮性と細胞内カルシウム ([Ca(2+) ](i)) 調節は,移植後の2週間と5週間で評価されました.
- ネイティブ・イン・シットゥー・ハートは,すべての実験のコントロールとして機能した.
主要な成果:
- 2週間後,無負荷および対照ミオサイトは,類似の収縮機能と[Ca2+]の調節を示した.
- 5週目までに,負荷のないミオサイトは,高レベルの細胞外カルシウムに対する反応が低下し,長期にわたるリラクゼーションと[Ca2+]の減少を示した.
- フォスフォランバンタンパク質濃度の上昇は,5週間の無負荷心臓では観察されたが,2週間の無負荷心臓では観察されなかった.
結論:
- 慢性的な心臓の解荷は,筋細胞の収縮機能の時間依存的な低下を誘導する.
- これらの発見は,長期にわたる心縮によって特徴づけられる状態における心機能の低下を示唆しています.
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