Brain rejuvenation via the gut in mice

Cognitive function can decline as we age, but maybe it doesn’t have to stay that way. Researchers have found a way to reverse that decline. In the case of older mice, they say, the answer might lie in the poop of younger mice (Nat. Aging 2021, DOI: 10.1038/s43587-021-00093-9).

Marcus Boehme, who did this work as a postdoc in John Cryan’s lab at University College Cork, says he has long been interested in links between the gut microbiome, immunity, and inflammation. Because the gut microbiome changes with age, Boehme devised an experiment to see if transplanting poop from young mice into old ones could change the gut microbiomes in the older mice and improve brain function.

The researchers found that the transplants changed not only the gut microbiomes of older mice but also their brain chemistry, resulting in higher concentrations of metabolites, including γ-aminobutyric acid (GABA) and N-glycolylneuraminate. The mice also performed better on memory and behavior tests.

These findings are more evidence that the “microbiome is a key player in aging,” says Katie Guzzetta, Boehme’s coworker and a PhD student in the Cryan lab. The two caution against translating the results into a treatment for humans, however. The researchers were giving mice the poop transplants twice a week in the lab, Guzzetta says, and it is not clear how long the improvement persists after the treatments end. The good news, the researchers say, is that the gut microbiome can be amended to change in brain function. Instead of poop transplants, perhaps food or lifestyle changes could make a difference in humans.