After someone has suffered a heart attack, their body replaces the damaged heart muscle tissue with non-beating scar tissue, compromising the heart's function. A new injectable biomaterial, however, may help the heart heal better.
The material is being developed at the University of California San Diego, by a team led by Prof. Karen Christman.
Back in 2012, Christman and colleagues created a hydrogel that was designed to be injected directly into the damaged areas of the heart. It would then form a three-dimensional scaffolding-like structure that cardiac cells could grow into, ultimately forming functional heart muscle tissue instead of scar tissue.
One problem with that version of the hydrogel lay in the fact that it couldn't be injected into the heart until at least one week after the attack had occurred – any earlier would pose too much of a risk of damaging the already weakened heart.
In order to get around that limitation, the scientists recently set about altering the material in such a manner that it could be administered right after a heart attack had occurred, either intravenously or via infusion into a blood vessel leading into the heart.
Those alterations included making the individual particles much smaller. The idea was that this would allow them to pass through tiny gaps between the cells in the walls of cardiac blood vessels, so they could make their way into the damaged heart tissue. Such gaps between endothelial (blood vessel wall) cells are likewise a form of heart attack damage.
When the injectable biomaterial was tested on rats and pigs, however, it was found that the particles bound to the endothelial cells, closing the gaps between them. This was still a good thing, though, as it caused the damaged blood vessels to heal faster.
As a result, normal blood flow to the heart muscle tissue was restored quicker, and there was less inflammation. Generally speaking, the smaller the amount of inflammation at a wound site, the smaller the amount of scar tissue that forms. Further rat experiments showed that the biomaterial particles could also be used to treat traumatic brain injuries and pulmonary arterial hypertension.
"This biomaterial allows for treating damaged tissue from the inside out," said Christman. "It’s a new approach to regenerative engineering."
A paper on the research was recently published in the journal Nature Biomedical Engineering.
