The exposome and liver disease - how environmental factors affect liver health.

Since the initial development of the exposome concept, much of the effort has been devoted to the characterization of the exposome through analytical, epidemiological, and toxicological/mechanistical studies. There is now an urgent need to link the exposome to human diseases and to include exposomics in the characterization of environment-linked pathologies together with genomics and other omics. Liver diseases are particularly well suited for such studies since major functions of this organ include the detection, detoxification, and elimination of xenobiotics as well as inflammatory responses. It is well known that several liver diseases are associated with 1) addictive behaviors such as alcohol consumption, smoking, and to a certain extent dietary imbalance and obesity, 2) viral and parasitic infections, 3) exposure to toxins and occupational chemicals. Recent studies indicated that environmental exposures were also significantly associated with liver diseases, and these include air pollution (particulate matter and volatile chemicals), contaminants such as polyaromatic hydrocarbons, bisphenol A and per-and poly-fluorinated substances, and physical stressors such as radiation. Furthermore, a major role is also played by the microbiome metabolites and the "Gut-Liver" axis. Exposomics is poised to play a major role in the field of liver pathology. Methodological advances such as the exposomics-metabolomics framework, genomics and epigenomics signatures of risk factors and cross-species biological pathway analysis should further delineate the impact of the exposome on the liver and open the way for improved prevention, new biomarkers of exposure and effects, and additional targets for therapies.