How oxygen levels synchronize heart muscle and blood vessel development

Researchers at Weill Cornell Medicine have found that fluctuations in oxygen levels in the developing heart trigger synchronized growth of both cardiac muscle and coronary vessels. This discovery, published in the Proceedings of the National Academy of Sciences, could lead to new treatments for heart failure by targeting the signaling pathways involved in this process.

Dr. Michael Harrison, an assistant professor of cell and developmental biology, explains that previous research had little understanding of how coronary vessels develop and why their growth is synchronized with that of the muscle tissue they serve. To uncover the mechanisms behind this coordination, his team used advanced imaging techniques to observe cell behavior in live zebrafish embryos, revealing that both muscle and vessels expand together, but sometimes muscle arrives first while other times vessels do.

Further investigation revealed that epicardial cells—the layer of cells surrounding the heart—are responsible for detecting low oxygen levels (hypoxia) and activating genes that produce signals coordinating the expansion of both muscle and vessels. This self-limiting feedback loop ensures that the heart maintains a balance between muscle and vascular growth.

Mutant zebrafish lacking coronary vessels showed excessive heart muscle expansion, indicating the crucial role of epicardial signaling in maintaining proper cardiac function. In humans, where the genetic pathways may be more complex, further research is needed to identify which specific genes and targets could be potential therapeutic options for heart failure.