- Switching from solitary jobs to more social, less energetic roles can reverse the aging process in bee brains.
- The change boosted levels of brain-protecting proteins in some bees.
- The research suggests aging may be reversible in human brains, too.
Getting out of a solitary rut and socializing like a more youthful version of yourself might be enough to reverse the aging process in your brain -- at least, if you're a bee.
When older honeybees in a new study were coaxed from their role as independent foragers to resume nursing the hive's larvae -- a more social job usually done by younger bees -- they regained a lost ability to learn new things. Taking on their younger jobs also boosted levels of two proteins that protect the brain from dementia and stress-related damage.
People are not bees, but the new findings fall in line with growing evidence that the size of our social networks, along with other lifestyle factors, can influence how we age.
The proteins implicated in the new study also appear in human brains, opening up the possibility that, like bees, changing our behavior could help us avoid some of the brain-centered pitfalls of aging.
"We might have to wait 20 years for a drug that might stimulate this protein in people," said Gro Amdam, a biologist at Arizona State University in Tempe. "But maybe we can make changes in how we deal with other people today and get some of the same benefits in a safer way than with drugs."
For more than a decade, scientists have documented a link in people between an active social life and more graceful aging, though it's been difficult to determine which causes which. Amdam thought honeybees might offer some insight because the insects are notoriously social, albeit in a more regimented way than people are.
When they are young, honeybees work as sociable nurses who take care of the larvae. Later in life, they switch jobs, becoming solitary foragers who fly out of the hive to collect nectar and pollen. When bees make the shift, they start to age quickly. Their bodies become battered, and they get worse at learning new tasks. And it's not just because they're out bumping into more things.
In experiments, Amdam and colleagues showed that, given two bees of the same age, the forager would age more quickly than the nurse. Besides being a less social job, foraging requires a huge leap in metabolism. A forager bee's metabolic rate is ten times higher than a hummingbird's.
To see how switching back to their younger roles might affect bee aging, Amdam and colleagues removed the nurse bees from two large colonies. As soon as the foragers returned and found the larvae unattended, some of them stayed home to fill in.
Immediately, the researchers tested some of these bees on a task that required them to learn to stick out their tongues in order to get a sugar reward. Young bees generally learn to make the association right away. Older bees can take six or more trials and still not get it.
None of the bees that had been working as foragers did well on the task at first. Ten days later, though, about half of the bees performed just as well as young bees did, the researchers reported in the journal Experimental Gerontology.
Brain dissections revealed that, compared to bees that didn't get better at the test over the course of the study, bees that improved had twice as much of a protein that has been implicated in a human studies as a protective factor against Alzheimer's, Huntington's and other degenerative brain diseases.
The work offers clues that could lead to more targeted drugs as well as better behavioral strategies for slowing the aging process, including a focus on social relationships and activities.
"We were able to give bees that were experiencing brain decline the ability they had when they were young," Amdam said. "That is a complete reversal of the brain decline that you see with aging."
The new study challenges a long-held notion that cognitive decline causes permanent structural damage to the brain, said Thomas Flatt, an evolutionary biologist at the University of Veterinary Medicine in Vienna.
"What I found amazing is that there's this plasticity in terms of the brain being able to revert to a more useful state," Flatt said. "That is really the cool part."
"Now the open question is to what extent can we find this in other animals, maybe even humans?" he added. "It's just a little bit too early to tell."