Microflora and age
Biologists have learned to determine the age of a person by his microbiome
Maria Azarova, Naked Science
Scientists from the University of California in San Diego (USA) have found out how, using a sample of human microflora, it is possible to determine its age using a machine learning technique developed in collaboration with IBM as part of the IBM AI Horizons program. The study was published in the journal mSystems (Huang et al., Human Skin, Oral, and Gut Microbiomes Predict Chronological Age).
As the authors explain, it has long been known that the human gut microbiome tends to change over time, but the role of the entire set of microbes living in the body, their ability to reflect age or influence the aging process has not been sufficiently studied before. In a 2014 study, another research group - from the University of Washington –compared the age predicted by stool analysis with the actual age of children who had a lack of body weight in the first months of life. Then the scientists noted that the difference between the present and the "microbial age" reflected the level of development of children and in some cases spoke about the risk of developing autism.
In a new study, biologists from the University of California decided to consider this factor in the context of adults and microbes that live both in the intestines and in the oral cavity or on the skin (on the hands and face). The study used 4,434 stool samples from residents of the USA and China, 2,550 saliva samples from people from the USA, Canada, Great Britain and Tanzania, as well as 1,975 samples of the skin microflora of Americans and Englishmen.
Anonymous study participants were divided into several groups, in general, their age ranged from 18 to 90 years, and body mass index – from 18.5 to 30. All of them did not have inflammatory bowel diseases or diabetes, did not take antibiotics at least a month before the tests, in addition, there were no pregnant, disabled or seriously ill among them.
The results showed that the microbes that live on the skin show the most accurate age of a person: the forecast turned out to be correct with an accuracy of 3.8 years. At the same time, microflora samples taken with a mouth swab coped with age determination with an accuracy of 4.5 years, and fecal analysis for intestinal microflora showed an indicator of 11.5 years. As it turned out, microbes from the oral cavity or intestines of people 18-30 years old were more diverse and numerous than the microbes of the elderly (60 years and older).
In addition, the research team found differences in the intestinal microflora of men and women, while microbes living on the skin or in the oral cavity did not depend on gender. In general, the microbiome of the skin and in the mouth changed equally and consistently with age in all people, but the intestinal microflora of each person was individual.
"The discovered ability to correlate human microflora with age will help advance future research on the role that microbes play in the aging process and age–related diseases, and will allow us to better test drugs that slow down old age," said one of the authors of the work Zhenjiang Xu.
The final goal of the study is to create similar algorithms for finding the connection of the microbiome, for example, with autoimmune inflammation. The new approach may lay the foundation for the creation of a non-invasive microflora test that will help clinicians better diagnose or assess the risk of a particular disease in a patient.
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