Reported in the journal Nature Biotechnology, a study showed human stem cell treatment can possibly return the hearts' functioning to better than 90 per cent of normal in macaque monkeys with heart attacks.
Heart-failure that causes nearly 10 million deaths worldwide, is a condition caused by lack of blood flow. The stem cells will help "form new muscle that will integrate into heart so it may pump vigorously again," said Professor Charles Murry from the University of Washington.
"Our findings show that human embryonic stem cell-derived cardiomyocytes can re-muscularise infarcts in macaque monkey hearts and, in doing so, reduce scar size and restore a significant amount of heart function. This should give hope to people with heart disease," Murry said.
For the study, the team induced experimental heart attacks in macaque monkeys.
Two weeks later, the researchers took heart cells that they had grown from embryonic human embryonic stem cells and injected them into and around the young scar tissue. Each animal received roughly 750 million of these human embryonic stem cell-derived cardiomyocytes.
At four weeks after treatment, the ejection fraction in the treated animals rose to 49.7 per cent, about half-way back to normal, as compared to the untreated control animals, which remained unchanged at about 40 per cent.
MRI scans showed that new heart muscle had grown within what had been scar tissue in the treated hearts, while no new muscle was seen in the untreated animals.
Moreover, the human heart cells had also formed new muscle tissue in the damaged region. The new muscle tissue had replaced 10 per cent to 29 per cent of the scar tissue, integrated with the surrounding healthy tissue and developed into mature heart cells, the researchers said.
Murry said that the research aims to develop a treatment that could be given to people shortly after a heart attack to prevent heart failure.
Because heart cells are long-lived there should be no need for additional treatments, he said. The transplanted stem cells would also be genetically altered to reduce the risk of immune rejection, which often complicates organ transplantation.
"What we hope to do is create a "one-and-done" treatment with frozen "off-the-shelf" cells that, like O-negative blood, can go into any recipient with only moderate immune suppression," Murry said.