Poo transplants and memory linked in study

A new study published today shows how faecal transplants from older to younger mice altered their gut microbiome, which in turn impacted their spatial learning and memory.

The research team hopes reversing the procedure could one day see faecal transplantation used to combat cognitive decline among the elderly.

David Vauzour, from University of East Anglia's medical school, said: "Ageing is an inevitable process that starts immediately after birth and ultimately leads to physical health problems as well as a decline in psychological well-being and cognitive function.

"Research has shown that the aging process may be linked with age-related changes in our gut microbiota.

"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 behaviour and cognitive function.

"We wanted to see whether transferring gut microbes from older to younger mice could affect parts of the central nervous system associated with ageing."

The team, which also comprises researchers from the Quadram Institute in the UK and the University of Florence, performed faecal transplants from older adult mice to younger adult mice and then assessed the young adults for markers such as anxiety, exploratory behaviour and memory.

After the transplantation, the team found significant differences in the young mice's microbial profiles.

While the young adults showed no significant changes in markers of anxiety, explorative behaviour or locomotor activity, they did show impaired spatial learning and memory as measured in a maze test.

These changes were paralleled by alterations in the expression of proteins associated with synaptic plasticity and neuro transmission, and changes to cells in the hippocampus part of their brains - responsible for learning and memory.

"Our research shows that a faecal transplantation from an old donor to a young recipient causes an age-associated shift in the composition of gut microbiota," Dr Vauzour said:

"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."

Professoe Claudio Nicoletti, from the University of Florence, said: "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.

"This work highlights the importance of the gut-brain axis in ageing 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."

Professor Arjan Narbad from the Quadram Institute said: "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.

"We have established an FMT service on the Norwich Research Park to treat serious gut infections and now want to explore in humans its effectiveness in combating a number of age-related conditions, including cognitive decline."

The research was funded by the Fondazione Cassa di Risparmio, the University of Florence and the Medical Research Council.

"Faecal microbiota transplant from aged donor mice affects spatial learning and memory via modulating hippocampal synaptic plasticity- and neurotransmission-related proteins in young recipients" is published in the journal Microbiome.

To see a video about the study, click here.