Rejuvenating hormone found to reverse symptoms of heart failure

"There has been evidence that circulating bloodstream factors exist in mammals that can rejuvenate tissues, but they haven't been identified. This study found the first factor like this," says senior study author Richard Lee of the Harvard Stem Cell Institute and Brigham and Women's Hospital.

Heart failure is a condition in which the heart can't pump enough blood to meet the body's needs, causing shortness of breath and fatigue, and it is becoming increasingly prevalent in the elderly. The most common form of age-related heart failure involves thickening of heart muscle tissue. But until now, the molecular causes and potential treatment strategies for this condition have been elusive.

To identify molecules in the blood responsible for age-related heart failure, a team led by Lee and Amy Wagers of the Harvard Stem Cell Institute and Joslin Diabetes Center used a well-established experimental technique: they surgically joined pairs of young and old mice so that their blood circulatory systems merged into one. After being exposed to the blood of young mice, old mice experienced a reversal in the thickening of heart muscle tissue. The researchers then screened the blood for molecules that change with age, discovering that levels of the hormone GDF11 were lower in old mice compared with young mice.

Moreover, old mice treated with GDF11 injections experienced a reversal in signs of cardiac aging. Heart muscle cells became smaller, and the thickness of the heart muscle wall resembled that of young mice. "If some age-related diseases are due to loss of a circulating hormone, then it's possible that restoring levels of that hormone could be beneficial," Wagers says. "We're hoping that some day, age-related human heart failure might be treated this way."