TPS 711: The exposome, Exhibition Hall, Ground floor, August 26, 2019, 3:00 PM - 4:30 PM
Background. High-resolution metabolomics (HRM) is a sensitive tool for measuring complex environmental mixtures and biological responses. However, most HRM applications, to date, have examined blood metabolites, the collection of which is invasive, making it extremely difficult to perform longitudinal biosampling. Saliva, an oral fluid and natural filtrate of blood that contains omics-features worthy of interrogation, may serve as an alternative, non-invasive biospecimen to blood plasma for use in HRM application.
Methods. We conducted the Saliva Metabolome in Traffic-related Health (SMITH) study to examine the feasibility of saliva as an alternative HRM biospecimen for use in detecting exposure to traffic-related air pollution (TRAP). We assessed exposures to several TRAP (e.g., black carbon, nitrogen oxides), and biomonitoring in a panel of 51 students living at various distance to a traffic hotspot. Monthly saliva and plasma samples were collected over four months and analyzed using HRM. We then conducted an untargeted Metabolome Wide Association Study (MWAS) workflow, including biological pathway analysis and chemical identification.
Results. A total of 29,013 metabolic features were reliably extracted from 204 saliva samples and 20,766 metabolic features from 175 plasma samples. 9479 features were shared in both saliva and plasma samples with moderate-to-strong correlation (ρ=0.55, p<0.0001). Using an untargeted MWAS workflow, we detected eight metabolic pathways consistently associated with TRAP in both saliva and plasma samples, including pathways predominantly associated with xenobiotic-mediated oxidative stress and acute inflammatory response, including as leukotriene and vitamin E metabolism.
Conclusions. With moderate-to-strong correlation and similar trends in pathway perturbation associated with TRAP in both biometrics, these results provide initial support for the use of saliva samples as a sensitive, and less invasive biometric for metabolomics analysis. Ongoing cluster analysis and chemical annotation will further clarify saliva metabolic perturbations associated with TRAP exposures to compare with metabolic changes observed in plasma metabolome.
