Apoptosis in myocarditis and dilated cardiomyopathy: Does enterovirus genome persistence protect from apoptosis? - An endomyocardial biopsy study

The purpose of this study was to examine the role of apoptosis in myocardit is and dilated cardiomyopathy. Apoptosis is an active energy-consuming mech anism of cell death in several cardiac diseases in different quality and qu antity. Methods: Endomyocardial biopsies from 81 patients with active (1) a nd chronic myocarditis (10), dilated cardiomyopathy with inflammation (DCMi ; 10) and without inflammation (DCM; 20), with borderline myocarditis and p ositive PCR for cytomegalovirus-DNA (6), adenovirus-DNA, or enterovirus-RNA (7), and controls (17) were analysed. Apoptosis was detected by using the TUNEL method. The highest rate of apoptotic cardiocytes was found in active and chronic myocarditis. One patient with severe active myocarditis demons trated 6.15% of apoptotic cardiocytes. Mean percentage of apoptotic cardioc ytes in chronic myocarditis was significantly increased (0.61 +/- 1.25%) wh en compared to controls (0.01 +/- 0.04%, P < .05). Particularly, patients w ith cytomegalovirus-DNA persistence in borderline myocarditis had an elevat ed rate of apoptosis (0.34 +/- 0.68%, P < .05). Increased rates of apoptosi s were found in borderline myocarditis with adenovirus-DNA persistence (0.2 0 +/- 0.57%) and in DCM (0.06 +/- 0.15%). Only a nonsignificant increase of apoptotic cardiocytes was found in DCMi (0.03 +/- 0.08%). No apoptosis was found in patients with enteroviral genome persistence in borderline myocar ditis. Conclusions: Apoptosis of cardiac cells is increased in myocarditis and dilated cardiomyopathy, being highest in severe active myocarditis. Apo ptosis thus contributes to cell death in active myocarditis and may play a role not to be neglected in dilated cardiomyopathy. Enteroviruses seem to h ave anti-apoptotic effects, because no apoptosis at all was found in the my ocardium. (C) 2001 Elsevier Science Inc. All. rights reserved.