Towards bacterial rejuvenation?
Researchers have identified specific gut bacteria that could tell a person’s age with relative precision. Should we expect the creation of a bacterial rejuvenating cocktail in the near future? It does not seem likely…
About this article
A wealth of information is hidden within the intestinal flora: diseases, inflammation, antibiotics use, diet… Could it also reflect our age? A team of English-speaking investigators went in search of an answer by analyzing the gut microbiota composition of 1,165 healthy people. They obtained a list of 39 bacterial species that make it possible to classify each sample in three age categories, with a 3.94-year precision. This precision level exceeds that of models developed so far, because this team is not the first to investigate a “microbiotic aging clock”.
Neither aging, nor rejuvenating
Could this mean that some bacteria are rejuvenating while others are associated to an early aging? It is proving difficult to make such a shortcut conclusion: pathogenic bacteria do not seem to be necessarily correlated to aging, while the abundance of bacteria deemed beneficial to our health does seem to extend youth. For instance, larger amounts of Campylobacter jejuni, a bacterium that causes diarrhea, are found in the intestinal flora of younger individuals, and this is not the case in elder people who seem to have acquired protective immunity over time.
Significant generational gap
Another key factor to consider is the major changes in ways of life (diet, sedentary lifestyle, environmental factors…) over the last century. In such a context, it is difficult to tell whether the flora composition of today’s young people will undergo the same changes as their elders. In other words, this calls into question the very principle of microbiotic aging clock… The authors, who are also the founders of a biotech company specializing in the treatment of age-related diseases and extension of human life, recognize this bias. A bacterial “elixir of youth” is still not within reach of our flora–or our supermarket shelves, at least for now…
Galkin F, Aliper A, Putin E, et al. Human microbiome aging clocks based on deep learning and tandem of permutation feature importance and accumulated local effects. bioRxiv, décembre 2018