Apoptosis in Endomyocardial Biopsies from Patients with Dilated Cardiomyopathy

Abstract

Apoptosis is an active energy-consuming mechanism of cell death, which may contribute to heart failure in patients with dilated cardiomyopathy. Dilated cardiomyopathy is a common clinical outcome of many prolonged cardiac insults, and therefore is considered as the most prevalent form of cardiomyopathy. Loss of heart mass is highly correlated with the heart failure and mortality, thus the purpose of this study was to define the apoptotic index in patients with dilated cardiomyopathy. Apoptosis was detected by the TUNEL method in 30 patients. Biopsies were obtained from the left ventricle, and at least three specimens were taken. TUNEL-positive cardiomyocytes were found in 26 of 30 cases (86.7 %) and the mean apoptotic index for the entire specimen series was 5.41 ± 1.70 %. The analysis showed that patients with dilated cardiomyopathy had significantly higher apoptotic index (P < 0.001) than healthy subjects. One subject (man, 41 years old) had a markedly elevated apoptotic index of 52.2 %. In the remaining subjects, the percentage of cardiomyocyte death ranged from 0 % to 15.5 %. The high percentage of apoptosis found in our study may be in accordance with the clinically manifested cardiac failure in patients with dilated cardiomyopathy since in most patients we recorded the left ventricular ejection fraction values below 30 %.