Can fecal transplants reverse signs of aging?

A new experimental study led by the Quadram Institute and the University of East Anglia (UEA) has found that transplanting fecal microbiota from young into old mice can reverse hallmarks of aging in the gut, brain, and eyes. In a reverse experiment, microbes transplanted from older mice caused inflammation in the brain of younger recipients and depleted a key protein that is required for normal vision. These findings suggest that the gut microbiota plays a crucial role in regulating the process of aging, and open the possibility of gut microbe-based therapies to combat decline in old age.

“This ground-breaking 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 in the form of gut microbe replacement therapy,” said study senior author Simon Carding, the head of the Gut Microbes and Health Research Program at the Quadram Institute, and a professor of Biology at UEA.    

Scientists have long known that the population of microbes that we carry in our gut is strongly linked to health. Many diseases are associated with changes in the types and behaviors of gut microbes. Some of these changes in the composition of gut microbiota happen as we age, negatively impacting our metabolism and immune systems, and leading to age-related diseases, such as inflammatory bowel syndrome, or cardiovascular, autoimmune, metabolic, and neurodegenerative disorders.

To better understand these changes, Professor Carding and his team transferred gut microbes from aged mice into young ones, and vice-versa. They found that the microbes from old donors led to loss of integrity of the lining of the gut in young recipients, allowing bacterial products to cross into circulation – a phenomenon that triggers immune responses and inflammatory reactions in the brain and eyes. Moreover, brain cells that are known to be associated with age-related chronic inflammation were also over-activated in young mice that received aged microbiome transplants, while proteins linked to retinal degeneration were elevated.

However, in old mice receiving transplants from young, healthy ones, the age-related detrimental changes in the gut, brain, and eyes were reversed. In future studies, the researchers aim to clarify how long these positive effects last, and to identify the beneficial components of the young donor microbiota and the ways in which they can affect organs distant from the gut.

“We were excited to find that by changing the gut microbiota of elderly individuals, we could rescue indicators of age-associated decline commonly seen in degenerative conditions of the eye and brain,” said study lead author Dr. Aimee Parker, a researcher at the Quadram Institute.

“Our results provide more evidence of the important links between microbes in the gut and healthy aging of tissues and organs around the body. 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,” she concluded.

The study is published in the journal Microbiome. 

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By Andrei Ionescu, Earth.com Staff Writer