Oxidative stress-mediated cardiac cell death is a major determinant of ventricular dysfunction and failure in dog dilated cardiomyopathy.
Cell death has been questioned as a mechanism of ventricular failure. In this report, we tested the hypothesis that apoptotic death of myocytes, endothelial cells, and fibroblasts is implicated in the development of the dilated myopathy induced by ventricular pacing. Accumulation of reactive oxygen products such as nitrotyrosine, potentiation of the oxidative stress response by p66(shc) expression, formation of p53 fragments, release of cytochrome c, and caspase activation were examined to establish whether these events were coupled with apoptotic cell death in the paced dog heart. Myocyte, endothelial cell, and fibroblast apoptosis was detected before indices of severe impairment of cardiac function became apparent. Cell death increased with the duration of pacing, and myocyte death exceeded endothelial cell and fibroblast death throughout. Nitrotyrosine formation and p66(shc) levels progressively increased with pacing and were associated with cell apoptosis. Similarly, p50 (DeltaN) fragments augmented paralleling the degree of cell death in the failing heart. Moreover, cytochrome c release and activation of caspase-9 and -3 increased from 1 to 4 weeks of pacing. In conclusion, cardiac cell death precedes ventricular decompensation and correlates with the time-dependent deterioration of function in this model. Oxidative stress may be critical for activation of apoptosis in the overloaded heart.
Cesselli
D
D
Department of Medicine, New York Medical College, Valhalla, NY, USA.
Jakoniuk
I
I
Barlucchi
L
L
Beltrami
A P
AP
Hintze
T H
TH
Nadal-Ginard
B
B
Kajstura
J
J
Leri
A
A
Anversa
P
P
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002304:Cardiac Pacing, Artificial; D002311:Cardiomyopathy, Dilated / Q000473:pathology / Q000503:physiopathology*; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D004195:Disease Models, Animal; D004285:Dogs; D004789:Enzyme Activation / Q000502:physiology; D006439:Hemodynamics; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress; D014176:Protein Biosynthesis; D017382:Reactive Oxygen Species / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism; D018754:Ventricular Dysfunction / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology*
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D003574:Cytochrome c Group; D017382:Reactive Oxygen Species; D055765:Shc Signaling Adaptor Proteins; D016159:Tumor Suppressor Protein p53; C002744:3-nitrotyrosine; D014443:Tyrosine; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases