Infarction induced myocardial apoptosis and ARC activation.
BACKGROUND
Apoptosis is thought to play a role in infarction induced ventricular remodeling. Apoptosis repressor with caspase recruitment domain (ARC) has been shown to limit cardiomyocytes apoptosis; however, its role in the pathogenesis of heart failure is not established. This study examines the regional and temporal relationships of apoptosis, ARC, and remodeling.


METHODS
Myocardium was harvested from the infarct borderzone and remote regions of the left ventricle (LV) at 2 (n=8), 8 (n=6), and 32 (n=5) wk after MI. Activated ARC was compared with myocardial apoptosis in each region at each time. Both were then compared with the progression of remodeling.


RESULTS
LV systolic volume increased by a factor 1.56±0.06 and 2.09±0.07 at 2 and 8 wk, respectively then stabilized by 32 wk (2.08±0.18). Activated ARC was elevated at 2 wk, diminished at 8 wk, and increased again at 32 wk in both regions. Apoptosis was elevated at 2 wk, and further increased at 8 wk. By 32 wk, apoptosis had diminished significantly.


CONCLUSIONS
In a large animal infarction model, remodeling varied directly with the degree of apoptosis and inversely with ARC activation, suggesting that ARC acts as a natural regulatory phenomenon that limits apoptosis induced ventricular remodeling.
Ekhterae
Daryoush
D
Gorman Cardiovascular Research Group, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19036, USA. dekhterae@gmail.com
Hinmon
Robin
R
Matsuzaki
Kanji
K
Noma
Mio
M
Zhu
Weizhong
W
Xiao
Rui-Ping
RP
Gorman
Robert C
RC
Gorman
Joseph H
JH
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D020169:Caspases / Q000737:chemistry / Q000378:metabolism*; D004195:Disease Models, Animal; D004452:Echocardiography; D020287:In Situ Nick-End Labeling; D008854:Microscopy, Electron; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D017434:Protein Structure, Tertiary; D012756:Sheep; D013599:Systole / Q000502:physiology; D020257:Ventricular Remodeling / Q000502:physiology*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D051028:bcl-2-Associated X Protein; D020169:Caspases