Living over 100 years is a rare feat for a human. New research from Tokyo Keio University medical school researchers released in the scientific journal “Nature” suggest that the secret of longevity of centenarians is believed to reside in their gut which may contain special bacteria that help prevent infections. Specifically, it is a unique microbiota (the billions of microorganisms living in our digestive tract) that generates unique compounds, known as “Secondary bile acids” and which could even protect against certain bacterial infections, including those caused by multidrug resistant bacteria.
To come to this conclusion, the researchers looked at the intestinal microbiota of 160 centenarians, an average of 107 years old and made comparisons with the gut microbiota of 112 people aged 85 to 89 and 47 people aged 21 to 55. The goal: to research the types of bacterial species present and the types of compounds they produce. They discovered that centenarians had higher levels ofe several bacterial species which produce molecules called “secondary bile acids,” generated by microbes in the colon, which help protect the intestines from pathogens and regulate the body’s immune responses.
A treatment path in the form of probiotics
It turns out that the centenarians had a distinct “signature” intestinal microbes that were not present in other age groups. Notably, researchers found elevated levels of a secondary bile acid called isoallolithocholic acid (isoalloLCA), which is able to inhibit the growth of Clostridioides difficile, an antibiotic-resistant bacteria that causes severe diarrhea and inflammation in the intestines. This molecule could therefore help maintain the balance microbial communities in the intestine, preventing the growth of bad bacteria. The team found that it is produced by a family of intestinal bacteria called Odoribacteraceae.
Thus, when mice infected with C. difficile received doses of Odoribacteraceae, the notorious bile-producing strains found in centenarians, this treatment reduced the amount of C. difficile excreted in their feces below detectable levels, suggesting it helped them avoid infection. “The interaction between the host and different processes in bacteria really suggests a potential for the maintenance of health. », Explains Damian Plichta, co-first author of the study. But still more to be carried out on a larger scale and longer term in several places of the world to explore in more detail this causal link between longevity and bile acids.
In the meantime, researchers believe the bacteria identified in this study could help scientists better treat infections caused by antibiotic resistant bacteria using morebile acids. Notably, isoalloLCA-producing bacteria species, such as Odoribacteraceae, could be used as probiotics to help maintain good gut health into old age. “The gut microbiome holds the keys healthy aging. Our work shows that future studies focusing on microbial enzymes and metabolites can help us identify starting points for treatment. », Conclude the researchers.