Fas expression and apoptosis correlate with cardiac dysfunction in patients with dilated cardiomyopathy

Fas is a transmembranous glycoprotein that mediates apoptosis. To elucidate the roles of Fas and of myocyte apoptosis in patients with dilated cardiomyopathy (DCM), the expression of Fas and the fragmentation of DNA were compared in endomyocardial biopsy specimens obtained from patients with DCM. Endomyocardial biopsy was performed on 19 subjects (16 with DCM and 3 control subjects) who also underwent cardiac catheterization and echocardiography. Fas and bcl-2 expression were assayed immunohistochemically, and in situ TdT staining was performed to estimate the number of apoptotic cells. Samples from the DCM patients stained more intensely with anti-Fas antibody than those from control patients (p<0.05). The percentage of in situ TdT-positive cells was significantly higher in the DCM group than in the control group (p<0.05). A correlation between Fas expression and in situ TdT staining was observed in 67% of myocytes in the DCM group. Moreover, the percentage of in situ TdT staining was significantly higher in subjects with severely impaired left ventricular systolic function than in those whose systolic function was mild to moderately impaired, or who had normal systolic function (p<0.05). The samples showed little expression of bcl-2. These results suggest that Fas expression and apoptosis may be involved in the progression of cardiac dysfunction in DCM.