When you suffer a heart attack, your heart-muscle cells become deprived of oxygen. Without oxygen, the cells soon whither and die—and are entombed within scar tissue. And once these cells die, they can’t be brought back to life.
But maybe—just maybe—there is another way to build new heart muscle. And if there is, scientists like Dr. Arjun Deb at the University of California, Los Angeles (UCLA), are hot on the trail to find it.
Published yesterday in the journal Nature, Deb and his team at UCLA’s Eli & Edythe Broad Center for Regenerative Medicine and Stem Cell Research have found some scar-forming cells in the heart have the ability to become blood vessel-forming cells—if given the proper chemical ‘boost.’
“It is well known that increasing the number of blood vessels in the injured heart following a heart attack improves its ability to heal,” said Deb. “We know that scar tissue in the heart is associated with poor prognosis. Reversing or preventing scar tissue from forming has been one of the major challenges in cardiovascular medicine.”
Tackling the ever-growing problem in heart disease can seem an almost insurmountable task. While heart disease claims more lives worldwide than any other disease, advances in modern medicine in recent decades mean that more and more people are surviving heart attacks, and living with what’s called ‘heart failure,’ for their hearts can no longer beat at full capacity, and they have trouble taking long walks or even going up a flight of stairs.
Transforming this scar tissue into functioning heart muscle has therefore been the focus of many research teams, including CIRM grantees such as Drs. Deepak Srivastava and Eduardo Marbán, who have each tackled the problem from different angles. Late last year, treatment first designed by Marbán and developed by Capricor Therapeutics got the green light for a Phase 2 Clinical Trial.
In this study, Deb and his team focused on scar-forming cells, called fibroblasts, and blood-vessel forming cells, called endothelial cells. Previously, experiments in mice revealed that many fibroblasts literally transformed into endothelial cells—and helped contribute to blood vessel formation in the injured area of the heart. The team noted this phenomenon has been called the mesenchymal-endothelial transition, or MEndoT.
In this study, the researchers identified the molecular mechanism behind MEndoT—and further identified a small molecule that can enhance this transition, thus boosting the formation of blood vessels in the injured heart. This study bolsters the idea of focusing on the creation of blood vessels as a way to help reverse damage caused by a heart attack. Said Deb:
“Our findings suggest the possibility of coaxing scar-forming cells in the heart to change their identity into blood vessel-forming cells, which could potentially be a useful approach to better heart repair.”