After years of failure, study finds hearts were 'pumping stronger' after stem cell therapy

Researchers have tried for decades to use stem cells to restore a damaged heart.

A new study shows they still haven't succeeded, but it offers the first glimmers of hope for heart disease, which is blamed for about 1 in 5 deaths in the United States, killing nearly 700,000 people a year.

The trial, by the Texas Heart Institute, showed that a one-time treatment of cells didn't keep heart failure patients out of the hospital. But it dramatically reduced the risk of stroke or recurrent heart attack for the nearly three years of the study, particularly among people who also had high levels of inflammation.

"At a year, the hearts were pumping stronger," said Dr. Emerson Perin, who led the research.

While he will have to conduct another clinical trial before winning approval for his approach, he has a path forward, Perin said.

"I now have the recipe," he said. "I know who I have to give (the cells) to, how I have to give them and in what dose."

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What are stem cells?

Stem cells are cells that can turn into a variety of other cells.

Every person arises from the combination of an egg and a sperm. Once fused, this combination of cells divides repeatedly, leading to every other cell in the body, from brain to gut cells.

Early cells with the ability to become every other cell are called "embryonic stem cells."

The human body also produces stem cells later in development that are less versatile than embryonic ones, but still may be useful in medicine. So-called mesenchymal stem cells can turn into bone, cartilage, muscle and fat.

In this study, researchers used precursor mesenchymal stem cells taken from three young, adult donors without heart disease. The goal was to alter the environment around the patients' hearts to decrease inflammation.

What the study showed 

In the study of 565 heart failure patients from 52 treatment centers, half were given high doses of these mesenchymal stem cells and the other half a sham procedure.

The study was designed to measure hospitalization and time until death, neither of which were statistically improved by the treatment.

But those who received the cells had a 58% reduced risk of heart attack or stroke, and among patients with high levels of inflammation the risk reduction rose to 75%.

These patients were already heavily treated with medication, so the improvements came on top of those therapies.

For years, Perin said, he's been seeing patients with heart failure get better when he gave them mesenchymal stem cells.

"Until now we didn't know why," Perin said. "Cell therapy has been this black hole. ... We now have insights into how it works."

What other researchers have to say   

Dr. Richard Lee, a stem cell biologist at Harvard University, said he found the study useful but thinks this type of stem cell has a long way to go to become a treatment for heart failure.

Drugs already available to treat heart failure are underused, he said, and doctors shouldn't wait around for newer therapies. "We should be doing better now,"  Lee said.

Despite these other therapies, heart failure continues to be a major problem for patients, said Dr. Roberto Bolli, who holds the distinguished chair in cardiology at the Jewish Hospital Heart and Lung Institute in Louisville, Kentucky.

"We can improve the symptoms of these patients, but still, their long-term outcome is not good. They will inexorably get worse and worse over time," said Bolli, who was not involved in the new research.

Also, the new study showed that the treatment was safe. None of the patients in this trial or in others over the years have suffered serious problems after receiving stem cells for heart disease.

This is first large study of stem cell therapy in heart disease to show an improvement for patients, Bolli said. "That's very significant."

Four other smaller trials have also shown promise in heart failure, including one he led, co-authored by Perin.

"I would say cell therapy is a promising treatment for chronic heart failure," Bolli said.

Why it's taken so long to get stem cells to work for heart disease patients

Researchers have been working for decades to get stem cells to benefit heart disease patients.

Dr. Joshua Hare, a cardiologist at the University of Miami who does stem cell research but was not involved in the current study, said he thinks the field would have moved faster if it had been better funded.

He hopes the new finding, though technically a failure, will encourage more investment.

Stem cell clinics, which "steal people's money" for procedures that don't help cardiac patients, have also created problems for the field, said Dr. Timothy Henry, a cardiologist and director of the Lindner Center at Christ Hospital in Cincinnati, Ohio.

Bolli said research has been so slow in part because it focused for 15 years on treating patients after heart attacks, hoping the cells would rebuild a damaged heart when given within a few days. At least 10 trials have shown that doesn't work.

Instead, the new trial and the four smaller ones suggest that stem cells are best at helping patients with long-standing heart failure, by reducing inflammation around the heart, which continues to damage its function.

Bolli said the new findings strongly suggest the need for a follow-up study concentrating on patients who also have inflammation. (Henry, who was on the steering committee for the new study, said he is optimistic that Mesoblast, the Australian company that funded the trial, will go forward with another study.)

"If that trial confirms these results, that will be a major advance in cardiovascular medicine," Bolli said. "We don't know of any other treatment that does that."

Contact Karen Weintraub at kweintraub@usatoday.com.

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This article originally appeared on USA TODAY: Heart disease study shows hope for stem cell treatment