Metabolomics as a powerful tool to decipher the biological effects of environmental contaminants in humans

Humans are exposed daily to a variety of environmental contaminants. For many of these, the associated health effects remain largely unexplored. There is growing evidence that untargeted metabolomics-based techniques could be used to identify simultaneously biomarkers of effect (i.e. disruption of endogenous metabolite profiles) and exposure (i.e. xenobiotic mixtures) in biological samples. This approach is expending quickly and has been used in several studies over the last 5 years to study biological effects of many environmental contaminants in humans. Hence, this review attempts to determine whether metabolomics might constitute a relevant tool to discover new early biomarkers of effects related to chemical exposure in humans. Published results suggest that common metabolic pathways are affected by specific groups of chemicals such as PAHs, metals, organochlorine compounds, pesticides, and endocrine disrupting plasticizers. Remarkably, disruption of cellular signaling pathways associated with oxidative stress may be primary drivers for further effects for all studied chemicals. In the future, the introduction of more sensitive analytical techniques to perform untargeted profiling of biological samples seems to be a good option to improve the coverage of the xeno-metabolome and to provide more relevant information on both chemical exposure and metabolic signatures of environmental contaminants. Some current challenges are finally discussed.