A promising future heart attack recovery option being developed is the use of cardiac patches that are placed on the organ itself. They deliver cell therapy directly to the site of injury. Up to now, studies have only brought about patches that are costly, fragile, time-consuming to prepare, and dangerous. They are made using live cellular material and therefore carry the risk of arrhythmia (irregular heartbeat) and tumor formation. That’s why a team of researchers from North Carolina State University and UNC-Chapel Hill decided to try a different approach that doesn’t use live cells. They developed a cell-free “off-the-shelf” artificial cardiac patch and it improved recovery in mice and pigs.
Study author Ke Cheng said:
We have developed an artificial cardiac patch that can potentially solve the problems associated with using live cells, yet still deliver effective cell therapy to the site of injury.
A cardiac patch works by helping the heart regenerate healthy tissue post-injury and restore the organ to proper function. Other approaches involve the use of living cells embedded in scaffolding that, when implanted, take on the role of the patients’ heart cells by mimicking the effects of beating heart tissue. The reason these aren’t reliable is that there’s a chance they’ll cause irregular heartbeats or trigger an immune response if the patients’ body’s cells fight the living cells in the patch.
The “off-the-shelf” patch, on the other hand, is made of a scaffolding matrix from decellularized pig cardiac tissue with synthetic cardiac stromal cells embedded within. The cardiac stromal cells are made of a biodegradable polymer that contains cardiac stromal cell-derived repair factors. The result is a patch that contains all the therapeutic benefits secreted by the cells but without the living cells that could trigger an unwanted immune response. The research has been published online in the journal Science Translational Medicine.
When they tested the artificial cardiac patch on a rat model of a heart attack, it resulted in a 50% improvement of cardiac function over three weeks compared to non-treatment, and a 30% reduction in scarring at the site of injury. Similarly, when they tested it on a pig model in a seven-day pilot study, it resulted in a 30% reduction in scarring in some regions of pig hearts and stabilized heart function.
The team also tested patches that had been frozen and found they worked just as well as freshly created patches.
Cheng said:
The patch can be frozen and safely stored for at least 30 days, and since there are no live cells involved, it will not trigger a patient’s immune system to reject it. It is a first step toward a truly off-the-shelf solution to cardiac patch therapy.
In the future, patches like these could be stored in a freezer at the hospital, ready to be used on a patient in need of heart repair.
