Now recognized as an important option for eliminating resistant C. difficile infection, fecal microbiota transplantation is gradually expanding its indications because of its metabolic benefits and its boosting effects on certain cancer immunotherapies. This new research, conducted at the University of East Anglia (UEA, Norwich), suggests that fecal transplantation may also reverse some aspects of aging. The findings, presented in the journal Microbiome, at least confirm the importance of the microbiota for health. Besides being important for healthy aging, of course.
The quest for eternal youth ironically finds a surprising but promising new clue in fecal microbiota. The British team has provided the first evidence that fecal microbiota transplantation is effective in reversing the signs of aging in mice, at least in the gut, but also in the eyes and brain.
In contrast, transplanting fecal microbiota from old mice to young mice accelerates their aging, with signs such as loss or depletion of a key protein needed for good vision. Once again, these results show that gut microbes play a role in regulating some of the negative effects of aging and open up the possibility of new treatments based on gut microbes to combat multiple organ decline later in life.
Lead author Professor Simon Carding of UEA Norwich School of Medicine and researcher in gut microbes describes the study as “groundbreaking” and its evidence as “exciting” for the direct involvement of gut microbes in aging and cognitive decline. While it is now known that the population of microbes in our gut, or gut microbiota, plays an important role in health and that most diseases are associated with changes in the types and behavior of bacteria, viruses, fungi, and other microbes in the microbiota until this study there was no clear link to aging.
Changes in the microbiota occur with age, negatively affecting metabolism and immunity, and have been linked to some age-related diseases, including chronic inflammatory bowel disease (IBD), cardiovascular disease, and certain autoimmune and metabolic diseases. However, the effects of changes in the microbiota are still far from understood. To identify them, researchers transferred microbiota from old mice to young, healthy mice and vice versa and studied the effects of these transplants on the inflammatory features of aging in the gut, brain, and eyes. These experiments show that:
- The microbiota in old mice induces a loss of integrity in the intestinal mucosa, allowing bacterial products to enter the circulation, triggering an immune response and inflammation in the brain and eyes.
- The inflammation spreads to specific immune cells in the brain.
- Levels of specific proteins are associated with increased retinal degeneration.
- Transplantation of microbiota from young to old mice, on the other hand, reverses these negative effects on the gut, eyes, and brain.
- In both young and old mice, transplantation of “young microbiota” increases the levels of beneficial bacteria previously associated with good health in young mice.
- The products produced by these beneficial bacteria lead to significant, positive changes in lipid (fat) and vitamin metabolism.
How long does this work? It still needs to be better understood how long these positive effects can last and to specify the beneficial components of the young microbiota and their impact on organs far from the gut. But the authors already believe that the treatment is a positive way to slow age-related deterioration. “By altering the gut microbiota in elderly people, we can reverse the indicators of age-related decline commonly seen in degenerative eye and brain diseases.” In addition to stool transplantation, the researchers remind us of the importance of diet on our gut bacteria and our health later in life.