Is the gut microbiota the new secret of youth?
What if rejuvenating the gut microbiota is all we need to do to preserve certain brain functions? Scientists are taking this idea very seriously in the hope of preventing age-related memory problems.
Memory loss, spatial orientation difficulties, anxiety disorders, etc.: ageing is often associated with psychological and cognitive decline. At the same time, the gut microbiota plays a major role in the development of brain areas dedicated to learning and memory, notably the hippocampus. This has led some scientists to suggest that microbiota ageing results in cognitive decline via the gut-brain axis.
Young mice… behaving like elderly mice
To evaluate this hypothesis, a team of researchers analyzed the gut microbiota of adult mice who had been transplanted bacteria from the digestive tracts of mice of the same age or of older mice. Bacterial composition was essentially the same following the fecal microbiota transplant (FMT), with the exception of four bacterial genera whose abundance was significantly lower in the mice that had received the aged microbiota. In the hippocampus of these mice, the expression of numerous proteins involved in important brain functions, such as learning and cognition, was altered.
Mice with memory loss
The mice were then subjected to two tests, the first assessing their ability to learn and remember a path through a maze, the second measuring their ability to recognize an object. In both cases, the mice given the microbiota of older mice performed less well than the other group. On the contrary, stool transplant from older mice had no effect on other aspects of ageing, such as locomotor activity or anxiety.
Restore the microbiota to slow down cognitive decline?
Therefore, cognitive decline due to fecal microbiota transplant from an aged donor resembles physiological decline observed during ageing, suggesting the gut-brain axis plays an important role in the ageing process. According to the authors, these results support therapeutic approaches that aim to improve cognitive functions and quality of life in the elderly by restoring their microbiota.
D'Amato A, Di Cesare Mannelli L, Lucarini E, et al. Faecal microbiota transplant from aged donor mice affects spatial learning and memory via modulating hippocampal synaptic plasticity- and neurotransmission-related proteins in young recipients. Microbiome. 2020;8(1):140. Published 2020 Oct 1. doi:10.1186/s40168-020-00914-w