APOPTOTIC CELL DEATH OF CARDIOMYOCYTES IN VARIOUS HEART DISEASES

细胞死亡一般有两种类型：坏死和凋亡，它们具有不同的形态和分子特征。在各种心脏疾病中，心肌细胞死亡的机制一直被认为是坏死。因此，我们研究了急性暴发性心肌炎和鳞状心肌梗死是否发生凋亡性心肌细胞死亡，如果发生凋亡，Fas (CD95)/Fas配体系统是否与凋亡有关。在这些疾病的许多心肌细胞中检测到核小体DNA断裂，这是细胞凋亡的生物学标志。Fas抗原蛋白的表达在部分心肌细胞中上调，而在对照组中未见上调。在心肌炎中，部分CD4+和CD8+ T细胞表达Fas配体mRNA和蛋白。Fas和Fas- l在部分浸润淋巴细胞中共表达。提示急性暴发性心肌炎和心肌梗死患者心肌细胞及浸润淋巴细胞均存在凋亡死亡。心肌细胞的凋亡可能与Fas/Fas-配体通路有关。

There exist two general types of cell death, necrosis and apoptosis, marked by different morphological and molecular characteristics. The mechanism of the cardiomyocyte dath has been classicaly believed to be necrosis in various heart diseases. Therefore, we examined whether apoptotic cardiomyocyte death occurs in acute fulminant myocarditis and scute myocardial infarction and if so, whether the Fas (CD95)/Fas ligand system is associated with the apoptosis. Nucleosomal DNA fragmentation, the biologic hallmark of apoptosis, was detected in numerous cardiomyocytes of these diseases. The expression of Fas antigen protein was upregulated in some of cardiomyocytes, but not in the control. In myocarditis, the expression Fas ligand mRNA and protein was expressed in some of CD4+and CD8+ T cells. Co-expression of Fas and Fas-L was observed in some infiltrating lymphocytes. These results indicate that there exist apoptotic death of the affected cardiomyocytes and infiltrating lymphocytes in acute fulminant myocarditis and myocardial infarction. It is likely that the apoptosis of cardiomyocytes might be associated with the Fas/Fas-ligand pathway.