Fighting Heart Disease With Pigs? San Diego Researchers Develop New Cardiac Therapy
Wednesday, September 11, 2019
Photo by Shalina Chatlani
Randall Newman and his wife went on an 8-mile bike ride just days before he started feeling strange.
“My arms started tingling, that’s when I was like this isn’t right,” Newman said.
Newman had a heart attack five years ago when he was 62. He said the heart attack was a surprise because he was normally feeling healthy.
He wanted to try everything he thought could help him get better, including new therapies.
“You know, try it," Newman said. "Everything can help to get your heart back to where it was,”
One of the things he was willing to try was pig hearts.
A jello-like therapy
At her lab at UC San Diego in La Jolla, biomedical engineer Karen Christman grinds up chemically altered pig heart tissue. This material is no longer a collection of cells. It’s been ground up and turned into a fine powder.
When she adds water to this material, it creates a hydrogel.
“Hydrogel is basically a physical material that’s gel-like or water-swollen," Christman said. "So the best example of a hydrogel — not one we use — is jello.”
After a heart attack, the heart tissue is damaged and it forms a scar. As a result, it becomes difficult for healthy cells to come in and replace the tissue.
This situation can slow the heart’s performance and could lead to future heart failure. Christman created this hydrogel to help repair the scarred heart tissue.
“When you inject into the person’s heart it sets up into a hydrogel and serves as this new template for healing into the heart,” she said. “So the body’s own cells come in migrate into it and help repair that damaged region.”
The gel is injected into the damaged part of the heart via a catheter. The gel opens the scar tissue and sticks around for about three weeks before biodegrading.
“You get more cardiac muscle and less scar tissue, you have better performance of your heart, which helps to slow down the progression to heart failure,” Christman said.
This therapy has been tested in animals hearts. But, Christman said, her clinical trial is the first time it was tested in human hearts.
Promising clinical trial results
Newman was one of those participants. So far, he’s happy with the results. He said his ejection fraction, or percentage of blood pumping out of the heart with each beat, at the time of his heart attack was around 48%.
“It went to like 62%. Which is almost normal,” Newman said.
That happened just a year after he finished the trial, he said
UC San Diego cardiologist Tony DeMaria helped design the pre-clinical trials on animal models. The therapy has promise, he said, especially since typical prescription drugs can often have side effects like excessive bleeding and fatigue.
“The hope would be that if the hydrogel is effective, then some of the medications we typically give to patients following a heart attack wouldn’t be necessary,” DeMaria said.
But, the FDA Phase 1 clinical trial only involved 15 patients. DeMaria said there is still more to test before he could safely recommend the treatment.
“When you’re looking for safety, then you need large samples, because let’s say you did a study of 30 patients and everybody did well,” he said. “But if the 31st had a terrible reaction, that would have implications.”
More work ahead
Back at her lab, Christman said the experience of patients such as Newman showed the trial had good results. All 15 patients improved in exercise.
But, there was one surprise.
“We saw more changes in later patients, so those who had a heart attack at least a year prior," Christman said. "Whereas we saw little or less changes in early patients in terms of heart size."
It wasn’t as effective in patients who had just suffered a heart attack, she said, because their bodies were still reacting to the incident and weren’t as receptive to the hydrogel.
Christman said the company making the gel, Ventrix, is raising funds for a Phase 2 clinical trial to look specifically at how this therapy works in later-stage heart attack patients.
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