UCLA researchers study heart attack scar tissue to find answers

New research by the University of California at Los Angeles (UCLA) may be able to explain why some individuals have extensive scarring from heart attacks than others, according to a UCLA release.

“Two individuals with the same degree of heart attack can end up with different amounts of scar tissue,” Dr. Arjun Deb, the study’s senior author and a member of Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA, said in the release. “Given the clear correlation between scar size and survival rates, we set out to understand why some hearts scar more than others. If we can reduce this scarring, we can greatly improve survival.”

The study was performed on mice but found that once formed, heart scar tissue will remain for life and reduces the heart's ability to pump blood. It also adds straight to the heart muscle, so that people who develop more scar tissue typically have a higher risk of heart rhythm problems, as well as well heart failure and sudden cardiac arrest, the release stated.

“Normally if you delete a collagen, you would expect the scar tissue size to decrease because collagen forms scar tissue," Deb said in the release. "We found, paradoxically, that the scar size actually increased by 50%,” said Deb, who is a professor of medicine in the division of cardiology at the David Geffen School of Medicine at UCLA and director of the school’s cardiovascular medicine research theme.

The researchers wanted to determine the role that collagen plays in scarring and to do this, they engineered a mouse model that could not produce type 5 collagen in scar tissue after a heart injury.

“Scar tissue without type 5 collagen is compliant like rubber,” Deb said in the release. “So when the heart fills with blood, the scar tissue expands in much the same way as a rubber balloon expands when it is filled with air.”

Deb's team worked with physicians and scientists to study the issue and found that a drug like Cilengitide could help, but the drug has not yet been approved by the Food and Drug Administration.