Researchers at Duke University’s Pratt School of Engineering have created a fully functioning artificial human cardiac patch large enough to repair damage typically seen in patients who have suffered a heart attack. The advance takes a major step toward the end goal of repairing dead heart muscle in human patients and is being developed by Ilia Shadrin, a doctoral student, and his advisor Nenad Bursac, PhD, professor of biomedical engineering.
The research is part of a seven-year, $8.6 million grant from the National Institutes of Health, and the study was published on the web at Nature Communications, an open access peer-reviewed journal, on November 28th.
Source: Duke University, Pratt School of Engineering
Right now, virtually all existing therapies are aimed at reducing the symptoms from the damage that’s already been done to the heart, but no approaches have been able to replace the muscle that’s lost, because once it’s dead, it does not grow back on its own. This is a way that we could replace lost muscle with tissue made outside the body.
– Ilia Shadrin
According to Ken Kingery at the Pratt School, heart patches “could conceivably be implanted over the dead muscle and remain active for a long time, providing more strength for contractions and a smooth path for the heart’s electrical signals to travel through. These patches also secrete enzymes and growth factors that could help recovery of damaged tissue that hasn’t yet died.” This is the first human heart patch that is large enough to cover the affected area while being as strong and electrically active as native healthy heart tissue.
Creating individual cardiac muscle cells is pretty commonplace, but people have been focused on growing miniature tissues for drug development. Scaling it up to this size is something that has never been done and it required a lot of engineering ingenuity.
– Nenad Bursac, PhD
Mr. Kingery reported that the cells for the heart patch are grown from human pluripotent stem cells, which can become any type of cell in the body. The published results improved on the researchers’ previous patches, which were just one square centimeter and four square centimeters. They successfully scaled up to 16 square centimeters and five to eight cells thick. Tests show that the heart muscle in the patch is fully functional, with electrical, mechanical and structural properties that resemble those of a normal, healthy adult heart.
This is extremely difficult to do, as the larger the tissue that is grown, the harder it is to maintain the same properties throughout it. Equally challenging has been making the tissues mature to adult strength on a fast timescale of five weeks while achieving properties that typically take years of normal human development.
– Ilia Shadrin
The researchers have demonstrated that these cardiac patches survive, become vascularized and maintain their function when implanted onto mouse and rat hearts, according to Mr. Kingery. There’s still much work to be done, of course, before the patch will be ready for human patients. Researchers will have to develop a much thicker patch than the current iteration, and the patch must also be vascularized and otherwise able to be integrated with existing muscle.