Preservation of Functional Microvascular Bed Is Vital for Long-Term Survival of Cardiac Myocytes Within Large Transmural Post-Myocardial Infarction Scar.

This study was aimed to understand the mechanism of persistent cardiac myocyte (CM) survival in myocardial infarction (MI) scars. A transmural MI was induced in 12-month-old Sprague-Dawley rats by permanent coronary artery ligation. The hearts were collected 3 days, 1, 2, 4, 8, and 12 weeks after MI and evaluated with histology, immunohistochemistry, and quantitative morphometry.

Sex-related differences in intrinsic myocardial properties influence cardiac function in middle-aged rats during infarction-induced left ventricular remodeling.

We previously determined that residual left ventricular (LV) myocardium of middle-aged rats had sex-related differences in regional tissue properties 4 weeks after a large myocardial infarction (MI). However, the impact of such differences on cardiac performance remained unclear. Therefore, our current study aimed to elucidate whether sex-related changes in MI-induced myocardial remodeling can influence cardiac function.

Effect of Chronic Heart Rate Reduction by I(f) Current Inhibitor Ivabradine on Left Ventricular Remodeling and Systolic Performance in Middle-Aged Rats With Postmyocardial Infarction Heart Failure.

Background: A large myocardial infarction (MI) initiates progressive cardiac remodeling that leads to systolic heart failure (HF). Long-term heart rate reduction (HRR) induced by the I f current inhibitor ivabradine (IVA) ameliorates left ventricular (LV) remodeling and improves systolic performance in young post-MI rats. However, the beneficial effects of chronic IVA treatment in middle-aged rats remain to be determined.

Structural composition of myocardial infarction scar in middle-aged male and female rats: does sex matter?

The present study was designed to determine whether the structural composition of the scar in middle-aged post-myocardial infraction (MI) rats is affected by the biological sex of the animals. A large MI was induced in 12-month-old male (M-MI) and female (F-MI) Sprague-Dawley rats by ligation of the left coronary artery. Four weeks after the MI, rats with transmural infarctions, greater than 50% of the left ventricular (LV) free wall, were evaluated.