Biomedical engineers at Duke University developed a “heart patch” to cover and repair heart tissue damaged by heart attacks that’s just as strong and active as real tissue.
The study surrounding the advancement, published in Nature Communications, details how this new patch is an enormous step forward in repairing dead heart muscle.
“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,” they study’s lead author, Ilya Shadrin told the Duke University Pratt School of Engineering. “This is a way that we could replace lost muscle with tissue made outside the body.”
After a heart attack, the damaged parts of the heart tissue die and do not regenerate. Instead, the heart develops scar tissue that cannot transport electrical signals – essential for proper beats – like a healthy heart does. With scar tissue, a person typically suffers from heart failure and other deadly complications. Over 12 million people worldwide experience these side effects.
The patch, in theory, would cover the dead muscle and provide a bridge for electrical signals to travel for a long, extended period of time. It also discharges enzymes that promote the recovery of damaged parts of the heart that didn’t die after a heart attack.
It’s made up of human stem cells derived from embryos and others that were induced into their pluripotent — able to become any cell from any part of the body — state. These stem cells grew cardiomyocyte cells, responsible for the muscle contraction that makes the heart beat; fibroblasts, the framework of the heart tissue; and endothelial and smooth muscle cells, those that create blood vessels. All of the cells are “rocked and swayed” into specific spots onto a jelly-like substance where they grow into the functioning patch.
“It turns out that rocking the samples to bathe and splash them to improve nutrient delivery is extremely important,” Shadrin said. “We obtained three-to-five times better results with the rocking cultures compared to our static samples.”
The patches are currently an appropriate size to be tested on rats, a human-sized patch would require a bigger, thicker version that’s fully vascularized – something that provides a tissue with blood vessels.
“We are actively working on that, as are others, but for now, we are thrilled to have the ‘size matters’ part figured out,” Shadrin’s advisor Nenad Bursac said.