Scientists in the USA and Great Britain have developed a method for determining the biological age of people by the intestinal microflora. Biological age information can be used to prevent premature death of a person if the analysis reveals warning signs. The results of scientific work are published in the bioRxiv preprint repository.
Colonies of bacteria live in the human intestine, the number of cells in which reaches 10 to the 14th power, which is about an order of magnitude higher than the number of cells in the body itself. It is known that microflora plays an important role in the formation of immunity, produces substances important for the nervous system, and also affects the aging process. Because the composition of the gut microbiome changes over the course of life, it is difficult to determine which bacteria are associated with the risk of certain diseases and aging.
The new study involved 1,165 people between the ages of 20-90 and 3,663 samples of their gut microbiome. Biologists have determined the composition of the microflora in each case and linked it to the biological age of the volunteers. The obtained data, including the properties of each type of microorganism, were used for deep learning of a neural network consisting of three hidden layers with 512 nodes in each, processing incoming information. As a training set, 90 percent of the samples were used, the rest were used for verification.
Testing has shown that the trained neural network predicted a person's age based on the composition of his microflora with an error of 3.94 years. Further analysis showed that 39 taxa of microorganisms determine the biological age of a person.
It turned out that aging has little to do with the presence of beneficial or harmful bacteria in the gut. For example, the number of cells of the pathogenic microorganism Campylobacter jejuni, which causes diarrhea, decreased with age, while species of the genus Eubacterium, useful for humans, on the contrary, increased their numbers. In addition, microorganisms common in older people do not necessarily contribute to aging and the development of age-related diseases.
