Abstract
BACKGROUND: Emerging evidence links fine particulate matter (PM(2.5)) and its polycyclic aromatic hydrocarbon (PAH) components to adverse health outcomes. However, the biological mechanisms driving these associations remain unclear. This study innovatively integrates personal exposure monitoring and untargeted metabolomics in an older adult population to investigate the differential impacts of individual PM(2.5)-bound PAHs on metabolic pathways and elucidate their roles in health risks. METHODS: In this study, we enlisted the participation of 112 healthy older adults. We employed personal samplers to monitor the concentrations of pollutants throughout the study period. Furthermore, we conducted an untargeted metabolomic analysis of plasma samples using a liquid chromatograph mass spectrometer (LC-MS). A general linear regression model was utilized to investigate the significant relationships between metabolites and pollutants. Metabolic pathway enrichment analysis was performed to reveal the disturbed metabolic pathways related to PM(2.5)-bound PAHs. RESULTS: Our study demonstrated that short-term exposure to PM(2.5)-bound PAHs may induce acute perturbations in plasma metabolites among the older adult population. We found that exposure to LMW PAHs in PM(2.5) were correlated with amino acid metabolic pathways, while HMW-PAHs are associated with fatty acid and cholesterol metabolism pathways. While PM(2.5) mass was higher in summer, the toxic PAHs component of PM(2.5) was substantially higher in winter, contributing to greater observed toxicity. CONCLUSION: The plasma metabolome presents a promising resource for biomarkers and pathways, elucidating the biological mechanisms of PM(2.5)-bound PAHs. Our findings suggest that the cholesterol and citric acid metabolites, as well as the cholesterol biosynthesis and citric acid cycle pathways they affect, may play important roles in the health damage caused by PAHs, providing potential insights into the pathogenic processes underlying the impact of PM(2.5)-bound PAHs.