Consistency between air and biological monitoring for assessing polycyclic aromatic hydrocarbon exposure and cancer risk of workers

Rapid and sensitive detection of wood smoke exposure biomarkers using europium fluorescent nanoparticle label/lateral flow immunoassay

Exposure to wood smoke is associated with various adverse health problems. Biomonitoring of smoke exposure-associated biomarkers provides accurate measurements of personally absorbed doses. As a specific metabolite of benzene, the quantitative measurement of S-phenylmercapturic acid (S-PMA) plays a vital role in evaluating human exposure to wood smoke. In this study, we developed an efficient lateral flow immunoassay (LFIA) approach for accurately and rapidly measuring S-PMA levels. Europium chelate nanoparticles (EuNPs) conjugated with purified polyclonal sheep anti-S-PMA antibodies were employed as the fluorescent detection probe. This work is based on a competitive immunoassay, where the target S-PMA competes with the immobilized antigen on the test lines for the limited antigen-binding sites on EuNP-conjugated antibodies. Due to this competition, the fluorescent intensity of the EuNPs is inversely proportional to the concentration of the target S-PMA in the sample, enabling quantitative measurement. Owing to the large Stokes shift, superior fluorescent brightness, and saturation of the EuNPs, S-PMA levels can be measured with a limit of detection of 0.32 ng/mL, a detectable range of 0.10-30 ng/mL, and a linear detection range of 0.25-30 ng/mL under optimized conditions. Stability testing revealed that the LFIA strips can be stored at room temperature for up to one year while maintaining excellent detection performance for S-PMA. These results demonstrate that the EuNP-based LFIA is a promising tool for accurate preclinical and point-of-care evaluation of wood smoke exposure. A major advantage of this approach is its ability to accurately analyze smoke biomarkers at anticipated low concentrations. The sensor system allows low-cost, rapid, and on-site data collection and quantification of wood smoke exposure.

Mesoporous Pd@Pt Nanoparticle Label/Lateral Flow Immunoassay Integrated with a 3D-Printed Smartphone Reader for Detection of Wood Smoke Biomarkers

Wood smoke exposure poses significant health risks, particularly in occupations such as firefighting, where short-term exposure to high levels of pollutants is common. The biomonitoring of wood smoke-associated biomarkers is crucial for assessing human exposure. S-phenylmercapturic acid (S-PMA), a key metabolite of benzene, has been widely used as a reliable biomarker for this purpose. However, current S-PMA detection methods lack the speed, portability, and user-friendliness required for widespread, on-site applications. In this study, we propose a novel detection system that integrates mesoporous Pd@Pt nanoparticle-mediated lateral flow immunoassay (LFIA) with a 3D-printed smartphone-based reader for detecting S-PMA. Performance testing with S-PMA in phosphate-buffered saline and spiked urine samples yielded limits of detection of 0.5 ng/mL and 2.5 ng/mL, respectively. The use of mesoporous Pd@Pt nanoparticles as signal amplifiers for LFIA, along with the integration of a 3D-printed device for accurate image acquisition, significantly enhanced the system's sensitivity, achieving detection limits well below the threshold recommended by the American Conference of Governmental and Industrial Hygienists. With remarkable stability and reproducibility, our method provides a noninvasive, highly sensitive, rapid, portable, low-cost, and user-friendly solution for the on-site assessment of wood smoke exposure in occupational settings, laying the foundation for future innovations in real-time environmental exposure monitoring.

Comparison of urinary 3-hydroxybenzo(a)Pyrene (3-OHBaP) and trans-anti-7,8,9,10-tetrahydroxy-7,8,9,10-tetrahydrobenzo(a)Pyrene (TetraolBaP) as biomarkers of exposure to carcinogenic BaP

INTRODUCTION

Biomonitoring of exposure to carcinogenic Benzo(a)Pyrene is generally based on measurement of urinary 3-hydroxybenzo(a)pyrene (3-OHBaP), but its analysis is complex and only reflects the BaP detoxification pathway. TetraolBaP, another BaP metabolite resulting from the metabolic activation pathway, is now available but has not yet been studied in occupational settings or compared with 3-OHBaP.

METHODS

Biomonitoring was carried out on 118 subjects working in the aluminium smelting industry. 3 urine samples were collected from each subject at the beginning and end of the working week. Pyrene metabolite (1-hydroxypyrene) and the two BaP biomarkers (3-OHBaP and TetraolBaP) were analysed using LC-Fluorescence and GC-NCI-MS-MS.

RESULTS

The workers studied were found to be highly exposed, with 1-OHP and 3-OHBaP frequently exceeding maximum recommended values in occupational settings. Maximum concentrations were measured at end of shift+16h for all biomarkers, highlighting dermal exposure and/or temporary storage. Correlations were strong between 1-OHP and 3-OHBaP (r = 0.68-0.75) as well as between 3-OHBaP and TetraolBaP (r = 0.67-0.78), and moderate between 1-OHP and TetraolBaP (r = 0.59-0.76). While TetraolBaP levels were higher at low PAH exposures, TetraolBaP increased much more slowly at high exposures, indicating progressive saturation of the bioactivation pathway. The [3-OHBaP]/[TetraolBaP] ratio was found to be significantly lower in chronically exposed workers. Urinary TetraolBaP levels corresponding to 1-OHP (2.5 μg/L or 1 μmol/mol creatinine) or 3-OHBaP (0.4 nmol/mol creatinine) guidance values were found to range between 0.84 and 0.95 nmol/mol creatinine.

CONCLUSIONS

TetraolBaP, resulting from carcinogenic BaP's metabolic activation pathway, was shown to be a diagnostically specific and sensitive biomarker for determining subjects' toxic internal exposure to PAHs in different contexts (occupational settings, environment) and assessing health risks.

Exploration of microRNAs from blood extracellular vesicles as biomarkers of exposure to polycyclic aromatic hydrocarbons

Exposure to polycyclic aromatic hydrocarbons (PAHs), ubiquitously environmental contaminant, leads to the development of major toxic effects on human health, such as carcinogenic and immunosuppressive alterations reported for the most studied PAH, i.e., benzo(a)pyrene (B(a)P). In order to assess the risk associated with this exposure, it is necessary to have predictive biomarkers. Thus, extracellular vesicles (EVs) and their microRNA (miRNA) contents, have recently been proposed as potentially interesting biomarkers in Toxicology. Our study here explores the use of vesicles secreted and found in blood fluids, and their miRNAs, as biomarkers of exposure to B(a)P alone and within a realistic occupational mixture. We isolated EVs from primary human cultured blood mononuclear cells (PBMCs) and rat plasma after PAH exposure and reported an increased EV production by B(a)P, used either alone or in the mixture, in vitro and in vivo. We then investigated the association of this EV release with the blood concentration of the 7,8,9,10-hydroxy (tetrol)-B(a)P reactive metabolite, in rats. By performing RNA-sequencing (RNA-seq) of miRNAs in PBMC-derived EVs, we analyzed miRNA profiles and demonstrated the regulation of the expression of miR-342-3p upon B(a)P exposure. We then validated B(a)P-induced changes of miR-342-3p expression in vivo in rat plasma-derived EVs. Overall, our study highlights the feasibility of using EVs and their miRNA contents, as biomarkers of PAH exposure and discusses their potential in environmental Toxicology.

Review of environmental airborne pyrene/benzo[a]pyrene levels from industrial emissions for the improvement of 1-hydroxypyrene biomonitoring interpretation

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants of significant public health concern, with several that are highly toxic to humans, including some proven or suspected carcinogens. To account for the high variability of PAH mixtures encountered in occupational settings, adjusting urinary 1-hydroxypyrene (1-OHP) levels by the total airborne pyrene (PyrT)/benzo[a]pyrene (BaP) ratio is essential for human biomonitoring (HBM). Given the complexity and cost of systematically monitoring atmospheric levels, alternative approaches to simultaneous airborne and HBM are required. The aim of this review was to catalog airborne PyrT/BaP ratios measured during different industrial activities and recommend 1-OHP-dedicated biological guidance values (BGV). A literature search was conducted. Seventy-one studies were included, with 5619 samples pertaining to 15 industrial sectors, 79 emission processes, and 213 occupational activities. This review summarized more than 40 years of data from almost 20 countries and highlighted the diversity and evolution of PAH emissions. PyrT/BaP ratios were highly variable, ranging from 0.8 in coke production to nearly 40 in tire and rubber production. A single PyrT/BaP value cannot apply to all occupational contexts, raising the question of the relevance of defining a single biological limit value for 1-OHP in industrial sectors where the PyrT/BaP ratio variability is high. Based upon the inventory, a practical approach is proposed for systematic PAH exposure and risk assessment, with a simple frame to follow based upon specific 1-OHP BGVs depending upon the occupational context and setup of a free PAH HBM interactive tool.

Comparison of bladder carcinogenesis biomarkers in the urine of traditional cigarette users and e-cigarette users

Background

During the use of electronic cigarettes (e-cigarettes), users are still exposed to carcinogens similar to those found in tobacco products. Since these carcinogens are metabolized and excreted in urine, they may have carcinogenic effects on the bladder urinary tract epithelium. This meta-analysis aimed to compare bladder cancer carcinogens in the urine of tobacco users and e-cigarette users using a large number of samples.

Methods

A systematic meta-analysis was performed using data obtained from several scientific databases (up to November 2023). This cumulative analysis was performed following the Preferred Reporting Items for Systematic Evaluation and Meta-Analysis (PRISMA) and Assessing the Methodological Quality of Systematic Evaluations (AMSTAR) guidelines, according to a protocol registered with PROSPERO. This study was registered on PROSPERO and obtained the unique number: CRD42023455600.

Results

The analysis included 10 high-quality studies that considered polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) and tobacco-specific nitrosamines (TSNAs). Statistical indicators show that there is a difference between the tobacco user group and the e-cigarette user group in terms of 1-Hydroxynaphthalene (1-NAP) [weighted mean difference (WMD)10.14, 95% confidence interval (CI) (8.41 to 11.88), p < 0.05], 1-Hydroxyphenanthrene (1-PHE) [WMD 0.08, 95% CI (-0.14 to 0.31), p > 0.05], 1-Hydroxypyrene (1-PYR) [WMD 0.16, 95% CI (0.12 to 0.20), p < 0.05], 2-Hydroxyfluorene (2-FLU) [WMD 0.69, 95% CI (0.58 to 0.80), p < 0.05], 2-Hydroxynaphthalene (2-NAP) [WMD 7.48, 95% CI (4.15 to 10.80), p < 0.05], 3-Hydroxyfluorene (3-FLU) [WMD 0.57, 95% CI (0.48 to 0.66), p < 0.05], 2-Carbamoylethylmercapturic acid (AAMA) [WMD 66.47, 95% CI (27.49 to 105.46), p < 0.05], 4-Hydroxy-2-buten-1-yl-mercapturic acid (MHBMA) [WMD 287.79, 95% CI (-54.47 to 630.04), p > 0.05], 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNAL) [WMD 189.37, 95% CI (78.45 to 300.29), p < 0.05], or N0-nitrosonornicotine (NNN) [WMD 11.66, 95% CI (7.32 to 16.00), p < 0.05].

Conclusion

Urinary bladder cancer markers were significantly higher in traditional tobacco users than in e-cigarette users.Systematic review registration: PROSPERO (CRD42023455600: https://www.crd.york.ac.uk/PROSPERO/).

Metabolism of benzo[a]pyrene after low-dose subchronic exposure to an industrial mixture of carcinogenic polycyclic aromatic hydrocarbons in rats: a cocktail effect study

Polycyclic aromatic hydrocarbons (PAHs) are interesting environmental pollutants for understanding cocktail effects. High-molecular-weight-PAHs (HMW-PAHs) are classified as probable or possible carcinogens; only benzo[a]pyrene (B[a]P) is a certain carcinogen in humans. Their toxicity depends on their metabolic activation. While 3-hydroxybenzo[a]pyrene (3-OHB[a]P) represents its detoxification pathway, trans-anti-7,8,9,10-tetrahydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene (tetrol-B[a]P) represents the carcinogenicity pathway. The objective was to study the metabolism of B[a]P and HMW-PAHs during chronic low-dose exposure to B[a]P or a PAH mixture. Rats were exposed orally 5 times/week for 10 weeks to low-levels of B[a]P (0.02 and 0.2 mg.kg^-1.d^-1) or to an industrial mixture extracted from coal tar pitch (CTP) adjusted to 0.2 mg.kg^-1.d^-1 B[a]P. Urinary levels of monohydroxy-, diol-, and tetrol-PAH were measured during weeks 1 and 10 by HPLC-fluorescence and GC‒MS/MS. After 1 week, the percentages of B[a]P eliminated as 3-OHB[a]P and tetrol-B[a]P were not different depending on the dose of B[a]P, whereas they were reduced by half in the CTP group. Repeated exposure led to an increase in the percentages of the 2 metabolites for the 0.02-B[a]P group. Moreover, the percentage of B[a]P eliminated as 3-OHB[a]P was equal in the 0.2-B[a]P and CTP groups, whereas it remained halved for tetrol-B[a]P in the CTP group. The percent elimination of HMW-PAH metabolites did not vary between weeks 1 and 10. Thus, dose, duration of exposure and chemical composition of the mixture have a major influence on PAH metabolism that goes beyond a simple additive effect. This work contributes to the reflection on determination of limit values and risk assessments in a context of poly-exposures.

The Use of Human Biomonitoring to Assess Occupational Exposure to PAHs in Europe: A Comprehensive Review

Polycyclic aromatic hydrocarbons (PAHs) are among the chemicals with proven impact on workers' health. The use of human biomonitoring (HBM) to assess occupational exposure to PAHs has become more common in recent years, but the data generated need an overall view to make them more usable by regulators and policymakers. This comprehensive review, developed under the Human Biomonitoring for Europe (HBM4EU) Initiative, was based on the literature available from 2008-2022, aiming to present and discuss the information on occupational exposure to PAHs, in order to identify the strengths and limitations of exposure and effect biomarkers and the knowledge needs for regulation in the workplace. The most frequently used exposure biomarker is urinary 1-hydroxypyrene (1-OH-PYR), a metabolite of pyrene. As effect biomarkers, those based on the measurement of oxidative stress (urinary 8-oxo-dG adducts) and genotoxicity (blood DNA strand-breaks) are the most common. Overall, a need to advance new harmonized approaches both in data and sample collection and in the use of appropriate biomarkers in occupational studies to obtain reliable and comparable data on PAH exposure in different industrial sectors, was noted. Moreover, the use of effect biomarkers can assist to identify work environments or activities of high risk, thus enabling preventive risk mitigation and management measures.