Stem cell therapy lowers risk of heart failure after a heart attack

People who received a stem cell infusion soon after a heart attack were less likely to develop heart failure than those who received standard care, according to the largest such study to date. This discovery provides some of the strongest evidence yet that stem cells can help the heart repair itself.

After acute cardiovascular diseaseThe heart muscle is permanently damaged and weakened, often leading to heart failure—when the organ cannot pump enough blood to meet the body's needs. There is currently no treatment other than a transplant or heart pump that can help. restore heart function.

As a potential solution, the researchers turned to stem cellswhich have the unique ability to transform into other types of cells. But previous studies on their use after a heart attack have shown mixed results. For example, trial version 2020 of 375 people found that bone marrow-derived cells, including stem cells that turn into blood cells, failed to reduce the risk of death more than standard care, such as cardiac rehabilitation programs and medications to lower blood pressure, reduce blood clots or lower cholesterol.

Armin Attar at Shiraz University in Iran and his colleagues took a different approach: They used mesenchymal stem cells, which can differentiate into structural cells such as cartilage and fat. These stem cells also release molecules that reduce inflammation and stimulate regeneration of surrounding tissues.

The team collected mesenchymal stem cells from cord blood and infused them into the hearts of 136 people within three to seven days of their first heart attack. While these stem cells can be obtained from participants' own fat and bone tissue, culturing enough of them for infusion can take a month, Attar said. Using cord blood allowed the team to deliver the treatment much faster, potentially increasing its effect, he said. A separate group of 260 people received standard care after their first heart attack.

Three years later, those who received stem cell therapy were on average 57 percent less likely to develop heart failure and 78 percent less likely to be hospitalized for it than those who received standard care. They also saw significant improvements in the heart's ability to pump blood, suggesting the treatment was helping. heart tissue recovers after damage.

“This is a big step forward,” says Attar. Although the therapy did not reduce the risk of death during the study period, the fact that it reduced hospitalizations was still noticeable, he says. Hina Chaudhry at the Icahn School of Medicine at Mount Sinai in New York. “Heart failure is the leading cause of hospitalization in the United States,” she says.

However, 80 percent of the participants were men, making it less clear how the therapy affects women, who are more susceptible to heart failure after a heart attack, Chaudhry says. However, in a separate analysis, Attar and his team found no differences in results based on gender. The study was also limited to young adults; all participants were between 18 and 65 years old. “It would be good to see a breakdown by age group because younger patients simply have more natural regenerative capacity and recover better from heart damage,” says Chaudhry.

These results provide compelling evidence that stem cells can help restore cardiac function after a heart attack. But treatment does not cure the heart completely. “There is no cure on this planet, no therapy to replace the lost [heart muscle cells]. And this is what will really change the game in this area,” says Chaudhry. However, “all of this research is teaching us more about the regenerative process in the heart and how to achieve it,” she says.