Abstract
Myocardial infarction remains the most common cause of heart failure with adverse remodeling. MicroRNA (miR)155 is upregulated following myocardial infarction and represents a relevant regulatory factor for cardiac remodeling by engagement in cardiac inflammation, fibrosis and cardiomyocyte hypertrophy. Here, we investigated the role of miR155 in cardiac remodeling and dysfunction following myocardial infarction in a dyslipidemic mouse model. Myocardial infarction was induced in dyslipidemic apolipoprotein E-deficient (ApoE−/−) mice with and without additional miR155 knockout by ligation of the LAD. Four weeks later, echocardiography was performed to assess left ventricular (LV) dimensions and function, and mice were subsequently sacrificed for histological analysis. Echocardiography revealed no difference in LV ejection fractions, LV mass and LV volumes between ApoE−/− and ApoE−/−/miR155−/− mice. Histology confirmed comparable infarction size and unaltered neoangiogenesis in the myocardial scar. Notably, myofibroblast density was significantly decreased in ApoE−/−/miR155−/− mice compared to the control, but no difference was observed for total collagen deposition. Our findings reveal that genetic depletion of miR155 in a dyslipidemic mouse model of myocardial infarction does not reduce infarction size and consecutive heart failure but does decrease myofibroblast density in the post-ischemic scar.
Highlights
Myocardial infarction (MI) with subsequent cardiac remodeling represents a major source of morbidity and mortality and remains the most common cause of heart failure
ApoE−/− mice, we investigated the effect of miR155 deficiency on cardiac function and remodeling following myocardial infarction in the context of dyslipidemia
In a previous study, we showed that serum cholesterol levels were not affected by additional miR155 deficiency in dyslipidemic ApoE−/− mice [6]
Summary
Published: 22 May 2021 and Institute for Molecular Cardiovascular Research (IMCAR), University Hospital Aachen, RWTH Aachen. Human Genetic Laboratory, University for Medicine and Pharmacy, 200642 Craiova, Romania
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