Mechanistic insights of personal PM2.5 and BC exposure on serum metabonomics

Abstract

Background: Black carbon (BC) is important component of fine particulate matter (PM2.5), which has finer particle size and can adsorb variety of toxic substances, yet the magnitude and pathophysiologic mechanisms of health effects by BC remain unknown.Methods: 76 healthy elderly adults in Jinan were recruited in the study, and participated in 5 repeat visits from September 2018 to January 2019. Each participant was required to wear portable samplers to measure personal exposure of PM2.5 (MicroPEM, RTI) and BC (AE51, AethLab Inc.) for three days during each visit. Ambient temperature and relative humidity were collected from nearest meteorological station. Participants were asked to complete detailed questionnaire and 24-hour time-activity dairy to investigate possible confounders. Serum samples were collected during each visit to perform untargeted metabolomics profiling analysis. We analyzed the association of personal exposure and metabolome using linear mixed-effects models and elucidated the involving metabolic pathways.Results: Personal exposure PM2.5 and BC were significantly associated with 348 and 443 metabolic features. Enrichment analysis indicated significant pathways including arginine biosynthesis, and metabolisms of phenylalanine, glycolysis, sphingolipid, which were closely related to metabolic and cardiovascular system. 20 out of 53 matched pathways showed more metabolic features significantly associated with BC than with PM2.5, while 32 pathways showed same metabolic features with BC and PM2.5. Besides, BC was distinctively associated with two pathways of Vitamin B6 and Caffeine metabolism, indicating that BC might have stronger magnitude of health effects than PM2.5, and have particular adverse effects on nervous system.Conclusions: PM2.5 and BC exposure can lead to adverse cardiometabolic effects by affecting metabolism processes. BC might be a more significant indicator of PM2.5 in health effects analysis, and the toxicity and biomechanism should be further analyzed in the follow-up study.