Myocardial apoptosis and mesenchymal stem cells with acute exercise

Area of Science:

• Cardiovascular Physiology
• Exercise Science
• Regenerative Medicine

Background:

• Aerobic exercise offers health benefits but can acutely injure the heart.
• Previous research indicates potential cardiac damage following intense physical activity.

Purpose of the Study:

• To investigate if acute moderate-intensity exercise induces cardiomyocyte damage in rodents.
• To determine if exercise stimulates mesenchymal stem cells (MSCs) to enhance protective paracrine effects on cardiomyocytes.

Main Methods:

• Rodents underwent a single session of moderate-intensity treadmill running.
• Cardiac apoptosis markers (cleaved PARP) and gene expression were analyzed post-exercise.
• Neonatal rat cardiomyocytes (NRCMs) were cultured with plasma from exercised rats and cocultured with MSCs.

Main Results:

• Exercise increased cardiomyocyte apoptosis (cell death) and altered myocardial gene expression.
• Exercise plasma induced NRCM death, attenuated by beta-adrenergic blockade.
• MSCs exhibited increased inflammatory cytokine secretion but no change in protective function or proliferation.

Conclusions:

• Acute moderate-intensity aerobic exercise in rodents causes temporary cardiomyocyte death mediated by plasma-borne factors, likely catecholaminergic stress.
• Despite an inflammatory response, MSCs do not alter their protective phenotype towards cardiomyocytes in an exercise-induced plasma environment.