Gut bacteria in Toxicology

Abstract

Recent studies have demonstrated a close relationship between the gut microbiota in the intestinal tract and the host's health status. Gut bacteria are not just "symbionts" but also play an important role in regulating various physiological functions of the host, including metabolism, immunity, and neurology. These diverse physiological regulatory functions are attributed to the intestinal bacteria’s ability to produce various metabolites, including short-chain fatty acids, branched-chain amino acids, aromatic amino acids, trimethylamines, secondary bile acids, and sulfur metabolites. Gut bacteria metabolize carbohydrates, proteins, fats, and many other compounds not digested and absorbed by the host, transferring them into the bloodstream as a variety of metabolites, which act as bioactive substances for the host. Recent innovations in metabolomics and metagenomics have led to the discovery of many metabolites derived from intestinal bacteria and genes related to their production, and the intestinal microbiota is considered a "metabolic organ" with a metabolic capacity equivalent to that of the liver. On the other hand, because they reside on the luminal side of the intestinal tract (outside the body), various environmental factors can easily affect gut bacteria. Furthermore, feces ultimately expel intestinal bacteria from the body, making it simple and noninvasive to collect samples of intestinal bacteria that reflect the body's environment. Therefore, the gut microbiota is a new target area for environmental chemical exposure effects. In this presentation, the speaker will discuss the findings on the toxicological effects of exposure to environmental chemicals on the intestinal microbiota and the possibility of a new indicator of effects, i.e., qualitative changes in the intestinal microbiota, based on adduct science, in addition to the conventional compositional (quantitative) changes in the intestinal microbiota.