Urinary carboxylic acid metabolites as possible novel biomarkers of exposures to alkylated polycyclic aromatic hydrocarbons

Metabolomic Changes after Subacute Exposure to Polycyclic Aromatic Hydrocarbons: A Natural Experiment among Healthy Travelers from Los Angeles to Beijing

“…Both urinary OH-PAH and PAHCA concentrations were significantly higher in Beijing compared to those in LA except for ∑OH-NAPs as determined in our previous study, , and geometric mean concentrations of urinary 1-OH-PYR, ∑OH-PHEs, ∑OH-FLUs, 2-OH-DBF, 2-PHECA, and 2-NAPCA in Beijing were 2.0 (95% confidence interval [CI]: 1.5–2.6), 3.0 (95% CI: 2.4–3.7), 5.2 (95% CI: 3.9–7.0), 7.1 (95% CI: 5.2–9.7), 2.7 (95% CI: 1.7–4.4), and 3.6 (95% CI: 2.3–5.8) times as high as those in LA, respectively (Table S2 in Supporting Information). To concisely compare exposure to representative parent unsubstituted PAHs and that to alkylated PAHs (i.e., phenanthrene and 2-methylphenanthrene), we presented concentrations of total OH-PHEs as well as 2-PHECA in Figure .…”

“…PAHs Exposure in Beijing and LA. Both urinary OH-PAH and PAHCA concentrations were significantly higher in Beijing compared to those in LA except for ∑OH-NAPs as determined in our previous study, 18,19 and geometric mean concentrations of urinary 1-OH-PYR, ∑OH-PHEs, ∑OH-FLUs, 2-OH-DBF, 2-PHECA, and 2-NAPCA in Beijing were 2.0 (95% confidence The concentrations were normalized to urinary creatinine concentrations. Both urinary OH-PHEs and 2-PHECA in Beijing were significantly higher than that in LA (both p < 0.001) according to linear mixed-effect models with a random intercept for participant.…”

“…A data set reported previously was applied here. , Urinary monohydroxylated PAHs (OH-PAHs) were assessed to indicate personal exposure to unsubstituted PAHs, and PAH carboxylic acids (PAHCAs) were assessed for exposure to alkylated PAHs as described previously. A total number of nine OH-PAHs, i.e., 1-hydroxypyrene (1-OH-PYR), 1-/2-/3-/4-/9-hydroxyphenanthrenes (∑OH-PHEs), 2-/3-hydroxyfluorenes (∑OH-FLUs), 2-hydroxydibenzofuran (2-OH-DBF), and 1-/2- hydroxynaphthalenes (∑OH-NAPs), and two PAHCAs, i.e., 2-phenanthrenecarboxylic acid (2-PHECA) and 2-naphtholic acid (2-NAPCA), were measured with gas chromatography–mass spectrometry (GC-MS; 7890A-5975C, Agilent Technologies, Santa Clara, CA) after derivation .…”

“…For instance, there are large spatial variations in PAH pollution between different countries, and China has been shown to be the largest emitter worldwide . In previous studies, we found that Los Angeles residents traveling to Beijing for 10 weeks exhibited elevated urinary levels of hydroxylated-PAHs (OH-PAHs) and PAH carboxylic acids (PAHCAs), which are likely metabolites of unsubstituted PAHs and alkylated PAHs, respectively . In the present study, we exploited this natural experimental opportunity brought by the drastic contrast in PAH exposure, indicating the increased air pollution in Beijing under a well-defined time frame, and performed metabolomic analysis on serum samples collected from 26 healthy young adults before, during, and after their travels, aiming to (1) identify key systemic metabolomic changes after a 6–8 week exposure to elevated levels of PAHs, (2) study the reversibility of metabolomic changes 4–7 weeks after the exposure cessation, and (3) compare the associations of metabolomic changes with unsubstituted and alkylated PAHs indexed by OH-PAHs and PAHCAs, respectively.…”

Urinary Amino-Polycyclic Aromatic Hydrocarbons in Urban Residents: Finding a Biomarker for Residential Exposure to Diesel Traffic

“…5−9 Certain alkylated-PAHs are more abundant in petrogenic sources (e.g., crude oil and its refined products) than in combustion emission, and hence, urinary metabolites of these PAH derivatives (e.g., PAH-carboxylic acids) have been suggested as exposure biomarkers reflective of petrogenic sources. 10,11 Several nitro-PAHs (e.g., 1-nitropyrene and 2-nitrofluorene) have been found to be abundant in DE, 12 and hence, their urinary metabolites may be used as a biomarker of DE exposure. For example, urinary amino-PAHs (APAHs), identified as major metabolites of nitro-PAHs, have been suggested as potential biomarkers of DE exposure.…”