Moscow Institute of Physics and Technology
Gut microbiota and disease
Our gut is full of bacteria – trillions of tiny microbes that support us during our lifetime. This diverse microbial community is called the gut microbiota and it plays an important role in human life: it is involved in nutrient absorption and vitamin synthesis, protects against pathogens, and regulates the immune, endocrine and higher nervous functions. Major advances in the scientific understanding of the role of microbiota in human health have occurred over the last 20 years, largely due to the development of molecular genetic methods in biology. The high scientific interest in microbiota is demonstrated by the fact that nearly $500 million have been spent on microbiota studies since 2008. A comprehensive way to explore microbiota – to define which microbes comprise it – is to sequence the DNA of the gut. This yields a combination of DNA sequences attributable to the different microbes. This collection of genomes, representing each bacteria found in the gut, is referred to collectively as the metagenome. This information has revealed the fact that microbiota consist of an immense biodiversity including hundreds of species, many of which are non-culturable (can not be grown in a laboratory). Interestingly microbiota can be viewed as a huge chemical reactor, yielding many products never seen in a lab. Although the composition of microbiota varies significantly from person to person, it changes only slightly in an average person over time, and the main factors that influence it include diet, lifestyle and antibiotics intake.
Scientific research projects devoted to studying microbiota specific to patients with different diseases prove that we can use the microbes for diagnostics. While it is important to understand that there is no single “BAD BUG” in the community, we can identify changes in the proportions of different bacteria that signal the onset of disease. The gut microbiota is viewed as a novel organ of the human body, which is very much adaptive in its nature. The level and degree of adaptation can actually provide insights on the state of the organism and the environment the organism is living in: level of pollution, food, water, climate and so on. Scientists are trying to diagnose and cure human diseases using this vast data. Some examples include inflammatory bowel disease, type 2 diabetes, atherosclerosis, metabolic syndrome, and colorectal cancer. For many of these diseases, significant changes from the healthy bacteria profile were reported, which provides a basis for a new generation of therapy and diagnostics at the same time – a new term being coined – theranostics. Theranostics is a perspective wherein the goal is to diagnose and cure disease at the same time. The microbiota may provide an opportunity to intervene at the earliest stage of the disease development.