New research published in the journal Nature Aging is offering some of the first insights into how gut bacteria can potentially influence brain aging in mammals. The study found fecal transplants from young to old mice reversed some aspects of age-related brain deterioration.
A variety of incredible studies over the past few years have uncovered fascinating links between the vast population of bacteria living in our gut and our general health. Autism, Parkinson’s disease, depression and even personality traits have all been associated in some way with the gut microbiome.
An influential 2017 study found fecal transplants from young killfish to older killfish dramatically extended lifespan in the old fish by 37 percent. But little research has so far explored young to old fecal transplantation in mammals.
This new research focused explicitly on brain aging. Fecal material was collected from young mice (aged three months) and transplanted into older mice (aged 20 months). The fecal matter was administered several times a week for four weeks.
At the end of the month-long experiment a number of cognitive and physiological changes were seen in the older mice given the young fecal transplants. Using a common maze test, the researchers noted the older mice displayed improvements to learning ability and long-term spatial memory.
Looking more closely at the animals’ brains the researchers saw reversals in age-related deterioration in the hippocampus. This observation was particularly prominent in regards to age-related changes to microglia activity. Microglia, a type of brain immune cell critical to cognition and neuroplasticity, have been implicated in neurodegeneration leading to age-related cognitive decline.
“This new research is a potential game changer, as we have established that the microbiome can be harnessed to reverse age-related brain deterioration,” says principal investigator John Cryan, from University College Cork (UCC). “We also see evidence of improved learning ability and cognitive function."
What all this means for aging humans is still very unclear. Cryan is cautious to stress there is lots of work to be done before these findings translate into any kind of human therapy.
Speaking to ScienceMag, microbiome expert Sean Gibbons, who did not work on this new research, called the study a “tour de force.” Gibbons does also note so far fecal transplant studies in mice have delivered a broad variety of different findings, suggesting we have plenty more to learn about the microbiome-mediated gut-brain relationship.
Paul Ross, director of the APC Microbiome Ireland research center, is optimistic these kinds of preliminary findings could lead to future microbial therapies for brain aging.
"This research of Prof. Cryan and colleagues further demonstrates the importance of the gut microbiome in many aspects of health, and particularly across across the brain/gut axis where brain functioning can be positively influenced,” says Ross, who did not work on this new research. “The study opens up possibilities in the future to modulate gut microbiota as a therapeutic target to influence brain health.”
The new study was published in the journal Nature Aging.
Source: University College Cork
