HMN 2025: How cells coordinate repair after heart attack

Over the course of evolution, the human heart has largely lost its ability to regenerate. Our distant ancestors were not afflicted by heart attacks—a condition that emerged primarily with modern lifestyles marked by poor diet, obesity, and other cardiovascular risk factors.

When a heart attack occurs, the healing process leads to the formation of fibrotic scar tissue. While this scar tissue helps stabilize the heart, too much scarring reduces the heart’s pumping capacity as functional muscle cells are lost. Over time, this can lead to chronic heart failure or even cardiac arrest.

A cellular map points the way to better recovery after a heart attack

Healing the heart is a highly coordinated process, relying on the precise interplay of many different cell types across both space and time. With their new molecular cell type atlas of the heart, a team from the University of Würzburg has visualized these intricate dynamics in time and space after injury, revealing how cells interact as the heart attempts to repair itself. The findings are published in the journal Nature Cardiovascular Research.

“Our cell atlas shows how various cell types communicate during heart repair and coordinate the healing process,” says Professor Dominic Grün, Chair of Computational Biology of Spatial Biomedical Systems and Director at the Institute for Systems Immunology at the University of Würzburg. “It lays a critical foundation for future research aimed at reducing scar formation after a heart attack and maintaining the heart’s pumping capacity.”

Using cutting-edge techniques like single-cell RNA sequencing and spatial transcriptomics, the team discovered that specific immune cells, called macrophages, guide connective tissue cells and help prevent overgrowth of scar tissue.

“This insight opens exciting new possibilities to actively support heart healing, for example by targeting specific signaling pathways,” says Dr. Andy Chan, the study’s lead author and a postdoctoral researcher in Grün’s group.

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