Our health largely depends on the environment in which we live. In fact, between 70% and 90% of the risk of developing a disease is determined by our exposome: a multitude of environmental (ie non-genetic) factors that we are exposed to throughout our lives. And yet we continue to have limited knowledge about what these environmental risks are, how they interact, and what biological processes they trigger.
A new study provides a unique resource for identifying novel biomarkers of early-life environmental exposures and understanding how those early-life environmental exposures affect our health. This is the first exposome study to systematically associate more than 100 environmental exposures during vulnerable periods of early life with molecular profiles in childhood.
The study has been led by the Barcelona Institute for Global Health (ISGlobal), a center promoted by the La Caixa Foundation.
“The first years of life represent a particularly important period, as exposures during these vulnerable periods of development can have pronounced effects at the molecular level, which are not clinically detectable until adulthood,” explains Martine Vrijheid, Head of the Children’s Program and Environment of ISGlobal.
In this study, the research team led by Vrijheid set out to associate multiple chemical, outdoor, social, and lifestyle exposures (92 in pregnancy and 116 when children were 6 to 11 years old) with profiles. molecular in the same children (DNA methylation and transcription of genes in blood, proteins in plasma and metabolites in serum and urine). The analysis included 1,301 mother-infant pairs from the Human Early Life Exposome (HELIX) project, a long-term cohort study in six European countries (Spain, UK, France, Lithuania, Norway and Greece).
Greater exposure to clean air environments in childhood will contribute to better health in adulthood. (Photo: Amazings/NCYT)
“High-performance computing allowed us to overcome one of the main challenges facing the analysis of many ‘omics’ data,” says Juan R González, co-author of the study. The analysis identified 1,170 significant associations (249 in pregnancy and 921 in childhood) that provide information about potential biological responses and sources of exposure. Exposures in pregnancy, such as maternal smoking, the heavy metal cadmium, or the trace element molybdenum, were mostly associated with changes in DNA methylation. In contrast, childhood exposures were associated with changes at all molecular levels, especially with serum metabolites. The results revealed, for example, that children can be exposed to chemical contaminants through their diet.
“We identified new associations between molecular profiles and childhood exposure to essential trace elements, climatic conditions, indoor air quality, and phthalates and parabens,” explains Léa Maitre, co-author of the study. “By visualizing these associations in the form of networks, we can better understand if a certain molecular profile is connected to various exposures or vice versa, and thus identify possible biological pathways,” she adds.
In fact, the study results provide plausible disease mechanisms for six exposure groups: copper, tobacco smoke, childhood indoor air quality, persistent organic pollutants, phthalates and parabens, and weather conditions. For example, childhood exposure to copper was associated with nearly 90 molecular features, including increased levels of C-reactive protein (a marker of inflammation). Temperature, humidity, and other weather conditions during the month prior to sampling were associated with blood metabolites involved in sleep and depression, proteins involved in thermoregulation, and immune response genes.
“With the wealth of exposomal and molecular information available in our catalogue, we offer a valuable resource to the scientific community to find biomarkers of exposure, identify sources of exposure, improve understanding of disease mechanisms, and ultimately advocate policy for public health,” concludes Vrijheid.
The study is titled “Multi-omics signatures of the human early life exposome”. And it has been published in the academic journal Nature Communications. (Source: ISGlobal)