A team of Harvard Stem Cell Institute scientists have discovered a protein that circulates in blood that can turn old hearts young, causing a mouse’s heart that has thickened and enlarged with age to revert back to a more youthful state.
The researchers hope that the discovery will lay a foundation for a new approach to therapy for a common form of heart failure that strikes elderly people, although much more research is needed before it could be tested in people.
“The change was unbelievably obvious,” said Dr. Richard T. Lee, a cardiologist at Brigham and Women’s Hospital and one of the leaders of the study, published Thursday in the journal Cell. “Usually we do quite sophisticated quantitative analyses of hearts and the shapes of the cells and things like that. . . . You could see what happened from the very first experiment.”
Outside researchers praised the study, which used a decades-old technique of stitching together the circulatory systems of two mice, called parabiosis. In this case, an old mouse was connected to a young mouse — a technique that coauthor Amy Wagers, a Harvard stem cell scientist, has utilized to examine the effect of blood on aging in various tissues. The researchers saw that something in the blood of the young mouse had a rejuvenating effect on the older mouse’s heart. Then, they started a systematic hunt for the factor that could be causing the change, ultimately finding that a protein called GDF-11 was the trigger.
“I’m really intrigued by this idea,” said Saul Villeda, a faculty fellow at the University of California, San Francisco. “What I’m interested in is how many [of these factors] will be tissue-specific. Will others be specific for the liver or the brain?”
In 2011, Villeda, who was not involved in the current research, found that blood from old mice could decrease the creation of new brain cells in young mice. Villeda identified a factor in the blood that seemed to be behind the effect, which also impaired learning and memory in young mice.