Just about a year ago, Harvard stem cell scientists reported promising news for elderly heart failure patients: In mice, they found, a protein called Growth Differentiation Factor 11 could undo heart damage wrought by aging.
But was it just a heart thing? Or might GDF11 apply more broadly to other ways that we get older but not better?
New research finds that the protein has similarly rejuvenating effects on brains and muscles — though again, only in mice, so it will be years before we’ll know whether humans might see similar benefits. But GDF11 does circulate in the human bloodstream as it does in the mouse, so it’s not totally outlandish to imagine that we might someday pop pills to increase our circulating GDF11 to stay stronger, smarter and generally healthier as we age. And already, researchers are discussing the need to seek potential benefits for patients with Alzheimer’s and other degenerative diseases.
Upcoming papers in the journal Science found that when given GDF11, some older mice — the equivalent of roughly 70-year-old humans — became able to run as long and smell as well as young mice.
The Harvard press release quotes Doug Melton, chair of the university’s Department of Stem Cell and Regenerative Biology, as saying he couldn’t “recall a more exciting finding to come from stem cell science and clever experiments. This should give us all hope for a healthier future. We all wonder why we were stronger and mentally more agile when young, and these two unusually exciting papers actually point to a possible answer: the higher levels of the protein GDF11 we have when young. There seems to be little question that, at least in animals, GDF11 has an amazing capacity to restore aging muscle and brain function.”
I spoke with Harvard stem cell biologist Amy Wagers, a leader in the GDF11 research, about what it means. Our conversation, edited:
I imagine our headline shouldn’t say ‘Fountain of Youth discovered.’ How do you prefer the effects of GDF11 to be described?
I like ‘healthy aging.’ It’s really important to say that we don’t have any idea whether GDF11 might affect lifespan at all, but it does seem to improve or enhance healthy function in multiple different tissues.
What’s our best understanding at this point of what GDF11 does biologically?
I would say our understanding is still in its infancy. What we know is that GDF11 is a protein that is produced and present in the bloodstream at high levels when you’re young and it goes away as you get older. When you add it back to older animals, there are beneficial effects on a number of different tissues.
At the organismal level, we know that it enhanced muscle repair capacity and skeletal muscle structure so that physical function is improved. We know that in the brain it increases the production of neural stem cells and functioning of the olfactory system. And we know in the heart it reverses cardiac hypertrophy. Continue reading