慢性心房颤动对人心房肌钙/钙调素依赖性蛋白激酶Ⅱ表达的影响

目的：探讨慢性心房颤动(房颤)对人心房肌细胞内游离Ca2+浓度及心肌组织钙/钙调素依赖性蛋白激酶Ⅱ (CaMKⅡ)表达的影响。 方法: 用激光共聚焦显微镜技术，对急性分离的慢性风湿性心脏病伴慢性房颤或窦性心律患者的心房肌细胞内游离Ca2+浓度进行测定，同时用Western blotting法检测心房肌组织CaMKⅡ表达的变化。 结果: 慢性风湿性心脏病伴慢性房颤患者心房肌细胞内游离Ca2+浓度显著高于窦性心律患者［(276.38±38.12）nmol/L vs （122.28±45.63)nmol/L, P<0.05］。慢性风湿性心脏病伴慢性房颤患者心房肌CaMKⅡ的表达明显强于窦性心律患者（10.14±0.31 vs 6.86±0.89， P<0.05）。 结论: 慢性房颤患者心房肌细胞内存在钙超载，Ca2+/CaMKⅡ信号转导途径可能是维持慢性房颤重要的病理生理基础之一。

Effect of chronic atrial fibrillation on Ca2 +/calmodulin dependent protein kinase Ⅱ expression in human atrial myocytes

AIM: To investigate the effect of chronic atrial fibrillation (AF) on free calcium concentration and expression of Ca2+/calmodulin dependent protein kinase Ⅱ (CaMKⅡ) in human atrial myocytes. METHODS: The intracellular free calcium concentration in acute isolated atrial myocytes and the expression of CaMKⅡ in atrial tissue of rheumatic heart disease patients with atrial fibrillation (AF) and with normal sinus rhythm were measured by laser scanning cofocal microscopy technique and Western blotting, respectively. RESULTS: The intracellular Ca2+ concentration in patients with atrial fibrillation was significantly higher than that in patients with normal sinus rhythm ［(276.38±38.12） nmol/L vs （122.28±45.63) nmol/L, P<0.05］. Western blotting analysis of atrial samples showed that CaMKⅡ expression was enhanced during chronic atrial fibrillation (10.14±0.31 vs 6.86±0.89，P<0.05). CONCLUSION: Chronic AF leads to intracellular calcium overload in human atrial myocytes. Ca2+/calmodulin dependent protein kinase signaling cascades may play an important role in maintenance of chronic AF.