Heart regeneration is one of the great challenges in cardiac research After a heart attack, heart cells, cardiomyocytes, do not have the ability to regenerate, but scientists do not know why. Now, a study from the University of Pittsburgh and UPMC seems to have found the answer.
As they publish in “Developmental Cell,” as heart cells mature in mice, the number of communication pathways called nuclear pores decreases dramatically.
While this might protect the organ from damaging signals, it might also prevent adult heart cells from regenerating, according to the researchers.
The study suggests that silencing communication between heart cells and their environment protects the heart from damaging stress-related signals, such as high blood pressure, but at the cost of preventing heart cells from receiving signals that promote regeneration .
“This work offers an explanation as to why adult hearts do not regenerate on their own, but newborn mouse and human hearts do,” says lead author Bernhard Kühn. “These findings represent an important advance in our fundamental understanding of how the heart develops with age and how it has evolved to cope with stress.”
While the skin and many other tissues in the human body retain the ability to repair themselves after injury, the heart does not. During human embryonic and fetal development, heart cells divide to form heart muscle. But when heart cells mature into adulthood, they enter a terminal state where they can no longer divide.
To better understand how and why heart cells change with age, Kühn teamed up with other Pitt researchers and biomedical imaging experts Yang Liu, associate professor of medicine and bioengineering, and Donna Stolz, associate professor of cell biology and pathology and associate director of the Center for Biological Imaging, to look at the nuclear pores. These perforations in the lipid membrane that surrounds a cell’s DNA regulate the passage of molecules to and from the nucleus.
“The nuclear envelope is an impermeable layer that protects the nucleus like asphalt on a highway,” explains Kühn, who is also a member of the McGowan Institute for Regenerative Medicine. “Like the manholes in this asphalt, the nuclear pores are pathways that allow information to pass through the barrier and into the core.”