Activation of the reward system is beneficial for the recovery following myocardial infarction

Central nervous system signals and peripheral innervations can influence peripheral immune cells` function and activity. A key component of the brain`s reward system- the ventral tegmental area (VTA) can also affect this regulation. Recent studies have revealed that VTA activation improves the immune response in cases of sepsis and cancer

The immune system plays a role in the recovery from myocardial infarction (MI) as it removes cell debris from infarct regions, regulates inflammation in the area and in later phases promotes scar formation.

In the present study, MI was induced in mice, followed by chemogenetic activation of dopaminergic neurons in the VTA for 4 and 15 days after MI induction Immune cells in the heart and lymph nodes as well as muscle-scar tissue of the heart, were analyzed.

As compared to control mice, VTA-activated mice displayed enhanced muscle tissue area and reduced scar tissue, which highly correlates with better cardiac function. On day 4 after MI, fewer leukocytes and specifically macrophages were found in the hearts and lymph nodes of VTA-activated mice, indicating an attuned immune cell activity in day 4. It remains unclear whether initial immune response was reduced or perhaps the transformation to the reparative phase occurred earlier.

These results indicate that VTA activation has positive effects on recovery post MI, and the effect is mediated at least partially, by the immune system.