Serum metabolomic pertubations among workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been associated with multiple health effects. Mechanistic studies using metabolomics could provide supporting evidence for such associations by identifying relevant biological pathways. In this study, we investigated metabolic perturbations in a cohort of TCDD exposed workers to better understand TCDD related health effects. Eighty one workers who had been exposed to TCDD in the past and 63 nonexposed workers were included in the study. Serum metabolites were detected using ultra high pressure liquid chromatography coupled online to a Q-TOF Premier mass spectrometer with a scan range of 70-1,000 m/z. Current plasma levels of TCDD were determined by high-resolution gas chromatography/isotope dilution high resolution mass spectrometry. TCDD blood levels at the time of last exposure were estimated using a one-compartment first order kinetic model. Differentially expressed metabolites were identified using linear regression models, partial least squares regression (PLSr) and a regression-based Bayesian variable selection approach. Features that were present in all quality control samples and had a coefficient of variation <30% were included in the analyses (n = 421 features). Adjusted linear regression analysis showed several significant perturbations (n = 27; P < 0.05) but these observations did not survive multiple testing correction (q value > 0.05). PLSr analyses and Bayesian variable selection regression analyses revealed no obvious metabolic perturbations associated with TCDD levels. This is the first metabolomic analysis related to TCDD exposure in humans. No significant metabolic features were identified. It is concluded that TCDD exposure at levels present in this study does not lead to significant perturbations of the serum metabolome.