An international team of researchers from the University of East Anglia, the University of Florence and the Quadram Institute has revealed that fecal transplants from older to younger mice can impact the learning and memory abilities of the recipient; by altering the gut microbiome of the younger mice they began to act more like the older donors with the changes including some of the same cognitive impairments older brains suffer from.
“Research has shown that the aging process may be linked with age-related changes in our gut microbiota,” Dr. David Vauzour from the University of East Anglia says in a release. “We wanted to see whether transferring gut microbes from older to younger mice could affect parts of the central nervous system associated with aging.”
The process of fecal transplants involves taking stool from a healthy person and transferring it to the colon of another person who is typically very sick and/or could have a bacterial infection. As the gut contains good/bad bacteria antibiotics can sometimes help to rid the body of what it needs to in order to stay healthy, using bacteria from a healthy donor’s stool can help to add to the good populations of bacteria in the microbiome. The procedure can help patients that are dealing with serious conditions such as cirrhosis, Crohn’s disease, and ulcerative colitis.
“Recently, the existence of two-way communication between the gut and the brain – known as the ‘gut-brain axis’ – has emerged as an important player in shaping aspects of behavior and cognitive function,” Dr. Vauzour explains.
After implanting the fecal materials into the younger adult mice they were studied for how the transplant affected anxiety, behaviour, memory. Findings showed the younger mice did not display significant changes in terms of anxiety or behaviour, but they did begin to display problems with spatial learning and memory, having trouble running through a maze test as older and mentally impaired mice do.
Upon further examination, the team found alterations in the proteins that have ties to neurotransmission and changes in the cells of the hippocampus are of the brain that forms new memories and helps to control learning and emotions.
“Our research shows that a fecal transplantation from an old donor to a young recipient causes an age-associated shift in the composition of gut microbiota,” Vauzour adds. “The procedure had an impact on the expression of proteins involved in key functions of the hippocampus – an important part of the brain that has a vital role in a variety of functions including memory, learning but also in spatial navigation and emotional behaviour and mood. In short, the young mice began to behave like older mice, in terms of their cognitive function.”
The team is now focussing on transplants from younger to older subjects, if the procedure works in this direction as well as it did in the other direction the team theorizes that the changes could help to reverse cognitive damage related to old age.
“While it remains to be seen whether transplantation from very young donors can restore cognitive function in aged recipients, the findings demonstrate that age-related shifts in the gut microbiome can alter components of the central nervous system,” Prof. Claudio Nicoletti from the University of Florence says.
“This work highlights the importance of the gut-brain axis in aging and provides a strong rationale to devise therapies aiming to restore a young-like microbiota to improve cognitive functions and quality of life in the elderly. Manipulating the microbiome is increasingly being seen as a way of improving or maintaining human health, and these results are an exciting indication of its potential for helping us age healthily” adds Prof. Arjan Narbad from the Quadram Institute.
