Faecal transplantation may seem like an unlikely way to reverse the aging process, but scientists have used evidence from studies in mice to achieve just that.
Scientists from the village Quadrat Institute and University of East Anglia found that transplanting fecal microbiota from young mice to old ones can alter the signs of aging in the gut, eyes, and brain. In a reverse experiment, microbes from old mice caused inflammation in the brains of young recipients and depleted a key protein needed for normal vision.
The study proves the direct involvement of intestinal microbes in aging and the functional decline of brain function and vision, and offers a potential solution in the form of intestinal microbial replacement therapy, said Professor Simon Carding of UEA Medical School and head of Gut. The Microbial and Health Research Program at the Quadram Institute.
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 Microbiomefound that the microbiota from old donors led to a loss of intestinal mucosa integrity, allowing bacterial products to enter the circulation, leading to immune system triggering 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 the beneficial components of young donor microbiota and how they affect organs removed from the gut.
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 microbiota replacement therapy (MRT) facility, also known as fecal microbiota transplantation (FMT), that will facilitate such trials as well as other trials for microbiota-related diseases.
Dr Amy Parker of the Quadra Institute, lead author of the study, said: “Our results provide more evidence of an important link between germs in the gut and healthy aging of tissues and organs around the body. We hope our findings will ultimately help us understand how we can manipulate our diets 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.