The microbes that populate the human gastrointestinal (GI) tract, called the microbiota, have profound effects on achieving and maintaining good health. Every day, scientists discover more ways in which the gut microbiota can improve or harm wellbeing. There is now evidence that transplanting fecal microbes from younger mice into older mice can reverse age-related, adverse changes in some organs. Is it possible that the fecal transplant process could reverse aging in humans?
The human gut microbiome changes with age. Some of these changes adversely affect metabolism and immunity. They can be associated with age-related disorders including GI, cardiovascular, neurologic, autoimmune, and metabolic diseases. Research from just last year showed how fecal transplants restored cognitive function in aging mice. This latest study by scientists at the Quadram Institute and the University of East Anglia in England only furthers the promising findings.
In the study, researchers demonstrated, in mice, that transplanting fecal microbiota from younger into older mice can reverse signs of aging in the gut, eyes, and brain. Conversely, fecal transplants from older into younger mice adversely affected the brain and vision in the younger mice.
“This groundbreaking study provides tantalizing evidence for the direct involvement of gut microbes in aging and the functional decline of brain function and vision, and offers a potential solution [for age-related decline] in the form of gut microbe replacement therapy,” says Simon Carding, head of the Gut Microbes and Health Research Program at the Quadram Institute, in a statement.
The researchers found that the microbiota from old donors damaged the lining of the GI tract, allowing bacterial products to cross into the circulatory system. The breach of integrity in the gut triggered activation of specific immune cells in the brain. In the eye, the team found specific proteins associated with retinal degeneration elevated in the young mice receiving microbiota from old donors.
The microbiota of young mice, and the old mice that received young microbiota transplants, also had more beneficial bacteria which were previously associated with good health in both mice and humans. The researchers analyzed the products which these bacteria produce. There were significant shifts in particular fats and vitamin metabolism of inflammatory cells in the brain and eye.
“Our results provide more evidence of the important links between microbes in the gut and healthy aging of tissues and organs around the body,” says Dr. Aimee Parker, of the Quadram Institute. “We hope that our findings will contribute ultimately to understanding how we can manipulate our diet and our gut bacteria to maximize good health in later life.”
The researchers are working to identify the beneficial components of the young donor microbiota and how fecal transplants affect organs distant from the gut. They caution about extrapolating their results directly to humans.
The research is published in the journal Microbiome.