Environmental exposures (PFASs and PCBs) and the Exposome
Environmental factors are believed to impact chronic diseases more than genetic factors significantly. To address this, the concept of the exposome was introduced. The exposome encompasses all exposures an individual experiences throughout life, including exogenous and endogenous factors. This concept offers a comprehensive framework for understanding how different environmental exposures interact with genetic factors to affect health and disease.
Environmental contaminants like per- and polyfluoroalkyl (PFAS) and polychlorinated biphenyls (PCBs) are critical elements of the exposome. These chemicals are particularly concerning due to their known or potential ability to disrupt the endocrine system, leading to health risks such as increased cancer risk, immune system disruption, and reproductive and developmental issues. Additionally, these substances can bioaccumulate in the body. People can be exposed to them through various sources, including food, drinking water, consumer products, and indoor and outdoor environments.
Targeted analysis of environmental contaminants
The method utilizes high-resolution mass spectrometry (HRMS) using Orbitrap technology, coupled with ultra-high-performance liquid chromatography (UHPLC) to determine the concentrations of 37 environmental contaminants across different chemical classes: PFAS (24 compounds), OH-PBDEs (metabolites of polybrominated diphenyl ethers (PBDEs); two compounds), OH-PCBs (metabolites of PCBs; seven compounds), HBCDs (hexabromocyclododecane; three isomers), and bisphenol A. The concentrations of the environmental contaminants are quantified using calibration curves and chemically labeled internal standards.
Simultaneously, features are relatively quantified at high resolution (70,000 FWHM) in negative ionization to enable relative quantification of other metabolites and lipids in the sample. We suggest complementing the assay with additional assays, e.g., metabolomic, lipidomic, bile acid, and SCFAs performed on the same samples to achieve a broader coverage of the exposome.
Platform strengths
Incorporating internal standards and calibration curves allows for accurate concentration determination of up to 37 different environmental contaminants. Additional compounds can be added to the panel upon request. The simultaneous relative quantification of metabolic and lipid features of unknown identity allows for relative comparisons between samples. Collection of MS/MS data provides high confidence in metabolite identification.
To ensure the quality and accuracy of environmental contaminant concentration measurements, we participate in the international external quality assurance program, the German External Quality Assessment Scheme (G-EQUAS).
Exemple data
Plasma: In a set of 100 samples, 19 environmental contaminants were detected. Eleven were found in the samples, allowing for up to 10% missing data. Simultaneously, 4,939 untargeted metabolite features were semi-quantified (allowing 10% missing values).