An Enzyme That Increases With Exercise Can Improve Memory In Mice, And Maybe People
July 9, 20204:42 PM ET
https://www.npr.org/sections/health-sho ... maybe-peop
Scientists say they've identified an enzyme that could help explain how exercise can slow or even reverse some signs of aging in the brain. "Exercise in a bottle" isn't around the corner, but it's not out of the question either.
The idea builds on an observation a few years ago that certain parts of the brain can actually grow, even in older people.
"Just because you have an old brain, it doesn't have to stay that way," says Saul Villeda, who researches aging at the University of California, San Francisco. "And one of the best-known interventions that has a benefit on the brain is exercise. The problem is many of the elderly are frail. They can't physically do the exercise."
So Villeda and his colleagues have been on the hunt for factors in the blood that are induced by exercise and can improve memory and other brain functions.
"Can we actually then transfer the benefits of exercise without actually having to do the physical component of the exercise itself?" he asks.
The team of researchers reported Thursday in the journal Science that it thinks it has a great lead.
The researchers took blood plasma from mice that got plenty of exercise and infused it into older sedentary mice. Sure enough, those mice showed improvements in their brains and in mental tasks in a maze.
The scientists then narrowed their search to about a dozen proteins in the blood. One in particular, an enzyme called GPLD1 [glycosylphosphatidylinositol specific phospholipase D1], seemed to be key. When scientists revved up the production of this enzyme in older mice, nerves grew in part of their brains, and the animals performed better in the maze.
"Exercise causes this protein to be produced in the liver," Villeda says. And among other things, when this enzyme enters the bloodstream, it seems to tamp down aspects of inflammation, which contributes to age-related brain damage. "The result of that is that you actually have improvement in cognitive function in these older mice."
The research team also looked at a group of older people at the UCSF Memory and Aging Center. Researchers measured their physical activity with Fitbits. Those who exercised more produced more of this enzyme.
Aging and exercise are both complicated, involving all sorts of variables that interact in unexpected ways. So Villeda had to think hard about whether a single protein could really have a big effect.
"I was definitely surprised that one protein could have that much effect," he says. But when he realized GPLD1 is changing about 100 other proteins, it seemed plausible.
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