About this Research Topic
Genome-wide association studies have made clear that genetic factors account for a limited fraction of the variability in chronic disease risk, highlighting the need for comprehensive environmental exposure assessments to estimate the risk attributed to environmental factors. The concept of the exposome, as coined by Christopher Wild in 2005 to describe the totality of lifelong human environmental exposures, including food, from conception onwards, and further refined by Rappaport and Smith (2010) in order to include psycho-social components and even biological responses, is the exposure counterpart of the genome in studies of disease etiology. The suggestion that the exposome, as a global measure of exposure, rather than a focus on exposure to single agents, can provide an improved basis for understanding disease risks constitutes a conceptual leap in the study of environmental health. However, traditional biomonitoring methodοlogy gives inadequate data both in-depth and in time, assessing only a few hundreds of chemicals, and often missing out many chemicals of concern. In addition, the exposome by definition covers a longitudinal component (e.g. repeated measurements in different phases of life) which is lacking in most molecular epidemiology studies.
Overall, there is not yet an established consensus concerning what, when, and where to measure in relation to the exposome. In addition, very little progress has been made toward establishing causal relationships between environmental exposures, intermediate biological effects and health outcomes. Application of global sets of biomarkers derived from holistic methodologies (omics) may provide valuable insights into the mechanisms that underlie exposome-genome interactions as well as adverse health outcome risks. Analyses of the transcriptome, proteome, metabolome, epigenome, and microbiome can provide molecular biomarkers of exposure/ early biological effect since they reflect all aspects of exposure, susceptibility, and outcome.
In this Research Topic, we aim to collate articles that will assist the process of unravelling the exposome using holistic (omics) approaches. We, therefore, welcome contributions (research articles, reviews as well as perspectives) on the application of omics technologies in exposome-related studies, with a focus on the following and related areas:
• omics-based biomarkers of exposure to specific agents or mixtures (including past and in utero exposures) as well as of early changes indicative of a risk of future disease
• intermediate biomarkers associated with exposures and disease risk and their exploitation in building mechanism-based causal exposure-disease associations
• use of the exposome approach to provide evidence of the health impacts due to multiple exposures and/or lifestyle factors
Keywords: intermediate disease biomarkers, epigenome, proteome, exposome, biomarkers, omics, meet-in-the-middle, transcriptome, metabolome, mixtures
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