A new study has discovered that people who live to be 100 or older have a unique microbiome that may protect against certain bacterial infections including those caused by multidrug-resistant bacteria. The findings, published in Nature, could point to new ways to treat chronic inflammation and bacterial disease.
A team of researchers studied microbes from faecal samples of 160 Japanese centenarians who had an average age of 107. They found that centenarians, compared to people aged 85 to 89 and those between 21 and 55, had higher levels of several bacterial species that produce molecules called secondary bile acids. Secondary bile acids are generated by microbes in the colon and are thought to help protect the intestines from pathogens and regulate the body’s immune responses.
Next, the researchers treated common infection-causing bacteria in the lab with the secondary bile acids that were elevated in the centenarians. One molecule, called isoalloLCA, was found to strongly inhibit the growth of the antibiotic-resistant bacterium Clostridioides difficile. Feeding mice infected with C. difficile diets supplemented with isoalloLCA similarly suppressed levels of the bacteria. The team also found that isoalloLCA potently inhibited or killed many other gram positive pathogens, suggesting that isoalloLCA may play a role in keeping the delicate equilibrium of microbial communities in a healthy gut.
“The ecological interaction between the host and different processes in bacteria really suggests the potential of these gut bugs for health maintenance,” said Plichta, a computational scientist at the Broad.
Additional studies from different regions around the world with more participants and longer duration could help find a causal link between longevity and bile acids. The bacteria identified in this study could help researchers in the meantime discover how to treat infections caused by antibiotic-resistant bacteria by manipulating bile acid.
“A unique cohort, international collaboration, computational analysis, and experimental microbiology all enabled this discovery that the gut microbiome holds the keys to healthy aging,” said co-first author Xavier, core institute member at the Broad. “Our collaborative work shows that future studies focusing on microbial enzymes and metabolites can potentially help us identify starting points for therapeutics.”
Source: Broad Institute of MIT and Harvard
Journal information: Sato Y, Atarashi K, et al. Unique bile acid-metabolizing bacteria in centenarians’ microbiome. Nature. Online July 29, 2021. DOI:10.1038/s41586-021-03832-5
