Relationship between residual viable myocardium and LV remodeling post-MI: Only part of the story

Review of cardiovascular imaging in the Journal of Nuclear Cardiology 2017. Part 1 of 2: Positron emission tomography, computed tomography, and magnetic resonance

Several original articles and editorials have been published in the Journal of Nuclear Cardiology in 2017. It has become a tradition at the beginning of each year to summarize some of these key articles in 2 sister reviews. In this first part one, we will discuss some of the progress made in the field of heart failure (cardio-oncology, myocardial blood flow, viability, dyssynchrony, and risk stratification), inflammation, molecular and hybrid imaging using advancement in positron emission tomography, computed tomography, and magnetic resonance imaging.

Nicorandil alleviates myocardial injury and post-infarction cardiac remodeling by inhibiting Mst1

BACKGROUND

Cardiomyocyte autophagy and apoptosis are crucial events underlying the development of cardiac abnormalities and dysfunction after myocardial infarction (MI). A better understanding of the cell signaling pathways involved in cardiac remodeling may support the development of new therapeutic strategies for the treatment of heart failure (HF) after MI.

METHODS

A cardiac MI injury model was constructed by ligating the left anterior descending (LAD) coronary artery. Neonatal cardiomyocytes were isolated and cultured to investigate the mechanisms underlying the protective effects of nicorandil on MI-induced injury.

RESULTS

Nicorandil reduced cardiac enzyme release, mitigated left ventricular enlargement and cardiac dysfunction after MI, as evaluated by echocardiography and hemodynamic measurements. According to the results of the western blot analysis and immunofluorescence staining, nicorandil enhanced autophagic flux and reduced apoptosis in cardiomyocytes subjected to hypoxic injury. Interestingly, nicorandil increased Mst1 and p-Mst1 levels in cardiomyocytes subjected to MI injury. Mst1 knockout abolished the protective effects of nicorandil on cardiac remodeling and dysfunction after MI. Mst1 knockout also abolished the beneficial effects of nicorandil on cardiac enzyme release and cardiomyocyte autophagy and apoptosis.

CONCLUSIONS

Nicorandil alleviates post-MI cardiac dysfunction and remodeling. The mechanisms were associated with enhancing autophagy and inhibiting apoptosis through Mst1 inhibition.