Transplanting human cardiac muscle cells into monkeys with heart failure can substantially restore the pumping capacity of the animals’ injured hearts, reports a study published online this week in Nature Biotechnology. Demonstrating this benefit in monkeys is a step toward advancing this therapy, which is based on human embryonic stem cells, to clinical trials in human patients.
In an untreated heart attack, blocked blood flow to the heart leads to the death of heart muscle cells, scarring and heart failure, which is the inability to pump enough blood to meet the body’s needs. Various new strategies for correcting heart failure have been found to work well in mice, but have gone on to fail in human trials. Studies in larger animals - such as monkeys, which are physiologically closer to humans - are more likely to predict whether a given therapy will work in people.
Charles Murry and colleagues induced heart attacks in monkeys, decreasing the pumping capacity of their hearts by more than 40%. They then injected about 750 million cardiac muscle cells, derived from human embryonic stem cells, into the monkeys’ hearts. The transplanted cells formed substantial amounts of new muscle in the injured hearts. Four weeks later, the treated monkeys regained about one-third of the pumping ability lost as a result of the heart attack. In two animals followed for 12 weeks, more than two-thirds of pumping ability was restored. If these results are reproduced in future clinical trials, this approach could provide a regenerative therapy for heart failure.