These findings suggest that gut microbes play a role in regulating some of the harmful effects of aging and open up the possibility of gut microbial-based treatments to combat decline later in life.
Professor Simon Carding of UEA Medical School in Norwich and head of the Intestinal Microbial and Health Research Program at the Quadram Institute said: “This groundbreaking study provides compelling evidence of the direct involvement of gut microbes in aging and functional brain decline. intestinal microbial replacement therapy. “
For some time it has been known that the population of microbes that we carry in our gut, collectively called the gut microbiota, is related to health. Most diseases are related to changes in the types and behavior of bacteria, viruses, fungi and other microbes in the human gut.
Some of these changes in microbiota composition occur with age, adversely affecting metabolism and immunity, and this has been associated with age-related disorders including inflammatory bowel disease as well as cardiovascular, autoimmune, metabolic, and neurodegenerative disorders.
To better understand the effects of these changes in the microbiota in old age, scientists from the Quadram Institute transferred gut microbes from old mice to healthy young mice, and vice versa. They then looked at how it affected the inflammatory signs of aging in the gut, brain and eyes, suffering from reduced function later in life.
A study published in the journal Microbiome found that microbiota from old donors led to loss of intestinal mucosa integrity, allowing bacterial products to enter the bloodstream, triggering immune triggers and inflammation in the brain and eyes.
Age-related chronic inflammation, known as inflammation, has been associated with the activation of specific immune cells found in the brain. These cells were also overactive in young mice that received microbiome transplantation with age.
In the eye, the team also found that specific proteins associated with retinal degeneration were elevated in young mice receiving microbiota from older donors.
In older mice, these harmful changes in the gut, eyes, and brain could be reversed by transplanting intestinal microbiota from young mice.
As part of ongoing research, the team is now working to understand how long these positive effects can last, and to identify beneficial components of young donor microbiota and how they affect organs removed from the gut.
Fecal transplantation cancels out aging
The microbiota of young mice and old mice that received young microbiota transplants was enriched with beneficial bacteria that had previously been associated with good health in both mice and humans.
Researchers have also analyzed the foods that these bacteria produce by breaking down elements of our diet. This revealed significant shifts, particularly in the metabolism of lipids (fats) and vitamins, which may be related to the changes observed in inflammatory cells of the eye and brain.
Similar pathways exist in humans, and the human gut microbiota also changes significantly later in life, but researchers warn of extrapolating their results directly to humans until similar studies are performed on the elderly.
The Quadram Institute is building a new facility for microbiota replacement therapy (MRT), also known as fecal microbiota transplantation (FMT), which will facilitate such trials as well as other trials for microbiota-related diseases.
Lead author of the study, Dr Amy Parker of the Quadram Institute, said: “We were delighted to discover that by changing the gut microbiota of the elderly, we can save the rates of age decline commonly seen in degenerative eye and brain conditions. .
“We hope that our findings will ultimately help us understand how we can manipulate our diet and our gut bacteria to maximize good health later in life.”
The study was funded by the Research Council for Biotechnology and Biological Sciences, part of the UK Research and Innovation.