Accidentally discovered that the lymphatic system can help the heart repair

After heart injury, the expression of a pro-lymphangiogenic growth factor activates the lymphatic system and stimulates white blood cells to help clear out dead cells, according to a Northwestern Medicine study published in the Journal of Clinical Investigation

Dr.

"We've identified a new target that could help clear dead tissue," said Thorp, who is also a professor of pediatrics

"This paper brings together a lot of interesting data and ultimately demonstrates the important function of lymphocytes in this process," added Guillermo Oliver, Ph.

After a heart attack, immune cells called macrophages help dispose of dead cells, engulfing and digesting them, a process known as efflux

In this study, the researchers prevented efferocytosis after an experimental heart attack in mice and observed that this modification resulted in decreased lymphatic activity and decreased the prolymphangiogenic growth factor vascular endothelial growth factor C (VEGFC) expression

These findings suggest that macrophages must digest dead heart cells to trigger expression of this growth factor

"Previous studies have shown that vascular endothelial growth factor is associated with improved cardiac function after injury, but the source of vascular endothelial growth factor was unknown, and this work identifies a link between macrophage efferocytosis and VEGFC production

VEGFC is also important for lymphatic activity; removing VEGFC from mice from the experiments reduced lymphatic activity and increased harmful inflammation after cardiac injury

"Mice without VEGFC had fewer lymphocytes in the marginal area of ​​the heart injury," said Kristofor Glinton, Ph.

Promoting the clearance of dead cells helps reduce reperfusion injury, the tissue damage that occurs when blood supply returns to the tissue after a period of hypoxia

Furthermore, according to Oliver, cross-communication of macrophages and lymph may exist elsewhere in the body

"This mechanism may not be unique to the heart, and lymphatic vessels are present in every injury and repair mechanism, so I'm eager to extend our research to other organs and injury models