PM_2.5 and its respiratory tract depositions on blood pressure, anxiety, depression and health risk assessment: A mechanistic study based on urinary metabolome

Effects of fine particulate matter (PM_2.5) and regional respiratory tract depositions on blood pressure (BP), anxiety, depression, health risk and the underlying mechanisms need further investigations. A repeated-measures panel investigation among 40 healthy young adults in Hefei, China was performed to explore the acute impacts of PM_2.5 exposure and its deposition doses in 3 regions of respiratory tract over diverse lag times on BP, anxiety, depression, health risk, and the potential mechanisms. We collected PM_2.5 concentrations, its deposition doses, BP, the Self-Rating Anxiety Scale (SAS) score and the Self-Rating Depression Scale (SDS) score. An untargeted metabolomics approach was used to detect significant urine metabolites, and the health risk assessment model was used to evaluate the non-carcinogenic risks associated with PM_2.5. We applied linear mixed-effects models to assess the relationships of PM_2.5 with the aforementioned health indicators We further evaluate the non-carcinogenic risks associated with PM_2.5. We found deposited PM_2.5 dose in the head accounted for a large proportion. PM_2.5 and its three depositions exposures at a specific lag day was significantly related to increased BP levels and higher SAS and SDS scores. Metabolomics analysis showed significant alterations in urinary metabolites (i.e., glucoses, lipids and amino acids) after PM_2.5 exposure, simultaneously accompanied by activation of the cAMP signaling pathway. Health risk assessment presented that the risk values for the residents in Hefei were greater than the lower limits of non-cancer risk guidelines. This real-world investigation suggested that acute PM_2.5 and its depositions exposures may increase health risks by elevating BP, inducing anxiety and depression, and altering urinary metabolomic profile via activating the cAMP signaling pathway. And the further health risk assessment indicated that there are potential non-carcinogenic risks of PM_2.5 via the inhalation route in this area.