Human stem cells help restore heart function in monkeys

For many experiencing heart attack, heart failure is an inevitability. But scientists are hoping to rewrite that story—by using stem cells to help restore heart function after myocardial infarction.

A team from the Washington School of Medicine in Seattle used human stem cells to improve the left ventricular ejection fractions in monkeys with heart failure.

Researchers—led by Charles Murry, MD, PhD, a professor at the UW School of Medicine and director of the school’s Institute for Stem Cell and Regenerative Medicine—published their findings online July 2 in Nature Biotechnology.

"Our findings show that human embryonic stem cell-derived cardiomyocytes can re-muscularize infarcts in macaque monkey hearts and, in doing so, reduce scar size and restore a significant amount of heart function," Murry said. "This should give hope to people with heart disease."

The team induced experimental heart failure in macaque monkeys, which have similar heart size and physiology to humans, by reducing ejection fractions from 65 percent to 40 percent.

Two weeks later, the researchers implanted embryonic human stem cells into the scar tissue. Four weeks after treatment, ejection fraction in those who treated with stem cells rose to 49.7 percent, while the untreated/control group remained near 40 percent. MRI showed heart tissue had grown in the treated group but not in the control group.

The new muscle in the treated group replaced 10 to 29 percent of scar tissue.

The goal, according to Murry, is to develop a treatment for patients after heart attack. A stem cell injection could be an efficient way to reduce heart failure by introducing long-living cells.

"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.