Urinary 1-hydroxypyrene in coke oven workers relative to exposure, alcohol consumption, and metabolic enzymes

Coking-Produced Aromatic Compounds in Urine of Exposed and Nonexposed Populations: Exposure Levels, Source Identification, and Model-Based Health Implications

Coking contamination in China is complex and poses potential health risks to humans. In this study, we collected urine samples from coking plant workers, nearby residents, and control individuals to analyze 25 coking-produced aromatic compounds (ACs), including metabolites of polycyclic aromatic hydrocarbons (PAHs) and their derivatives, chlorophenols, and nitrophenols. The median concentration of total ACs in urine of workers was 102 μg·g-1 creatinine, significantly higher than that in the other two groups. Hydroxy-PAHs and hydroxy hetero-PAHs were the dominant ACs. Workers directly exposed from coking industrial processes, i.e., coking, coal preparation, and chemical production processes, showed higher concentrations of hydroxy-PAHs and hydroxy hetero-PAHs (excluding 5-hydroxyisoquinoline), while those from indirect exposure workshops had higher levels of other ACs, indicating different sources in the coking plant. The AC mixture in workers demonstrated positive effects on DNA damage and lipid peroxidation with 5-hydroxyisoquinoline and 3-hydroxycarbazole playing a significant role using a quantile g-computation model. Monte Carlo simulation revealed that coking contamination elevated the carcinogenic risk for exposed workers by 5-fold compared to controls with pyrene, pentachlorophenol, and carbazole contributing the most, and workers from coking process are at the highest risk. This study enhances understanding of coking-produced AC levels and provides valuable insights into coking contamination control.

Internal exposure risk based on urinary metabolites of PAHs of occupation and non-occupation populations around a non-ferrous metal smelting plant

The emission of various metals from non-ferrous metal smelting activities is well known. However, relative investigations on potential occupational exposure of organic pollutants are still limited. Herein, total of 619 human urine samples were collected from workers engaged in smelting activities and residents living near and/or far from the smelting sites, and ten mono-hydroxylated metabolites of polycyclic aromatic hydrocarbons (OH-PAHs) in human urine were determined. The median levels of Σ₁₀OH-PAHs in smelting workers (25.6 ng/mL) were significantly higher (p < 0.01) than that of surrounding residents (9.00 ng/mL) and rural residents as the control (8.17 ng/mL), indicating an increase in occupational PAH exposure in non-ferrous metal smelting activities. The composition profiles of OH-PAH congeners were similar in three groups, in which naphthalene metabolites accounted for 76-82% of the total. The effects of smoking, drinking, gender, BMI, and occupational categories on urinary OH-PAHs were considered. The partial correlation analysis showed an insignificant effect of non-ferrous metal smelting activities on PAH exposure for surrounding residents. In the health risk assessments, almost all smelting workers had cancer risks exceeded the acceptable level of 10^-6. This study provides a reference to occupational PAH exposure and reinforce the necessary of health monitoring among smelting workers.

Association of occupational exposure to polycyclic aromatic hydrocarbons in workers with hypertension from a northeastern Chinese petrochemical industrial area

Elevated urinary polycyclic aromatic hydrocarbon metabolites have been linked to an increased risk of cardiovascular diseases (CVDs). However, for petrochemical workers with potentially high PAH exposure, it remains largely unknown whether the link will be amplified. Thus, this work aimed to investigate 14 urinary mono-hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) in 746 petrochemical workers working in a Chinese petrochemical industrial area and their association with the risk of hypertension using the binary logistic regression. Metabolites of naphthalene, fluorene, phenanthrene, and pyrene were frequently detected in the 746 urine samples analyzed (>98%), with Σ₁₀OH-PAH concentration in the range of 0.906-358 ng/mL. 2-hydroxynaphthalene accounted for the largest proportion of ten detected OH-PAHs (60.8% of Σ₁₀OH-PAHs). There were significant correlations between these metabolites and other factors, including gender, age, and body mass index. Diastolic blood pressure, not systolic blood pressure, was significant positively associated with the urinary Σ₁₀OH-PAH concentrations of the petrochemical workers. Elevated urinary 2/3-OH-Flu was significantly associated with an increased risk of hypertension (adjusted odds ratio: 1.96, 95% confidence interval: 1.20-3.18, p = 0.007), suggesting that PAH exposure in petrochemical workers was a driving factor of hypertension. In the stratified analysis, the association was more pronounced in those who were overweight with older age. Although the PAH exposure risk in petrochemical workers based on the estimated daily intakes was relatively low. Given the long-term impact, we call attention to CVDs of petrochemical workers.

The interaction effects of FEN1 rs174538 polymorphism and polycyclic aromatic hydrocarbon exposure on damage in exon 19 and 21 of EGFR gene in coke oven workers

Polycyclic aromatic hydrocarbon (PAH) exposure and genetic susceptibility were conductive to genotoxic effects including gene damage, which can increase mutational probability. We aimed to explore the dose-effect associations of PAH exposure with damage of exons of epidermal growth factor receptor (EGFR) and breast cancer susceptibility gene 1 (BRCA1), as well as their associations whether modified by Flap endonuclease 1 (FEN1) genotype. Two hundred eighty-eight coke oven male workers were recruited, and we detected the concentration of 1-hydroxypyrene (1-OH-pyr) as PAH exposure biomarker in urine and examined base modification in exons of EGFR and BRCA1 respectively, and genotyped FEN1 rs174538 polymorphism in plasma. We found that the damage indexes of exon 19 and 21 of EGFR (EGFR-19 and EGFR-21) were both significantly associated with increased urinary 1-OH-pyr (both P_trend < 0.001). The levels of urinary 1-OH-pyr were both significantly associated with increased EGFR-19 and EGFR-21 in both smokers and nonsmokers (both P < 0.001). Additionally, we observed that the urinary 1-OH-pyr concentrations were linearly associated with both EGFR-19 and EGFR-21 only in rs174538 GA+AA genotype carriers (both P < 0.001). Moreover, FEN1rs rs174538 showed modifying effects on the associations of urinary 1-OH-pyr with EGFR-19 and EGFR-21 (both P_interaction < 0.05). Our findings revealed the linear dose-effect association between exon damage of EGFR and PAH exposure and highlight differences in genetic contributions to exon damage and have the potential to identify at-risk subpopulations who are susceptible to adverse health effects induced by PAH exposure.

Polycyclic aromatic hydrocarbons (PAHs) levels in urine samples collected in a subarctic region of the Northwest Territories, Canada

Traditional food consumption for Indigenous peoples is associated with improved nutrition and health but can also pose potential risks via exposure to contaminants. Polycyclic aromatic hydrocarbons (PAHs) are compounds of interest due to their widespread presence (e.g., their metabolites are detected in up to 100% of the Canadian population) and their toxicological potential. To better understand the range of exposures faced by Indigenous populations in northern Canada and to address a contaminant of emerging concern identified by the Arctic Monitoring and Assessment Programme, a multi-year biomonitoring study investigated levels of PAH exposure in subarctic First Nations communities of the Northwest Territories, Canada. Secondary data analysis of banked samples from a subset of the cross-sectional study was done. PAHs and cotinine markers in the urine samples (n = 97) of participants from two regions from the Mackenzie Valley (Dehcho and Sahtú) was completed by liquid and gas chromatography coupled with mass spectrometry. Also, participants completed a 24-hr recall food survey. When compared according to age/sex categories, the GM of several biomarkers (1-hydroxypyrene, 1-naphthol, 2-hydroxyfluorene, 2-hydroxyphenanthrene, 2-naphthol, 3-hydroxyfluorene, 3-hydroxyphenanthrene, 4-hydroxyphenanthrene, 9-hydroxyfluorene, 9-hydroxyphenanthrene) appeared higher than observed for the general Canadian population. The PAHs levels observed were, however, below clinical levels associated with adverse health outcomes. Altogether, these elevated biomarkers are metabolites of pyrene, naphthalene, fluorene and phenanthrene. Statistically significant non-parametric associations were observed between several biomarkers and i) the consumption of cooked meat in the last 24 h; and, ii) smoking status (self-reported status and adjusted on urine cotinine level). This work is the first to report PAH levels in a northern Canadian population and provides local baseline data for monitoring the effects of changes to climate and lifestyle over time. These findings will support regional and territorial decision makers in identifying environmental health priorities.

Internal exposure levels of polycyclic aromatic hydrocarbons in children and adolescents: a systematic review and meta-analysis

Polycyclic aromatic hydrocarbons (PAHs) are widely found in the environment, and comparing to adults, children are more vulnerable to PAHs exposure. Urinary metabolites of PAHs are used as preferred biomarkers to estimate the PAHs exposure. Systematic review on the internal exposure level of children and adolescents is rare. We aimed to calculate the internal exposure levels of PAHs in children and adolescents and compare the levels of PAHs internal exposure in various children groups. We searched PubMed, OVID, Web of Science, EBSCO, ACS, and four Chinese databases, and all studies examining the urinary concentrations of PAHs in children and adolescent were identified. The total exposure level of 11 PAHs metabolites were pooled. Standard mean difference (SMD) and 95% confidence intervals (CIs) of PAHs urinary concentration were calculated and pooled by RevMan5.3 to compare the exposure levels of different children groups. We found that 1-OHPyr, 2-OHNap, 2-OHFlu, 3-OHPhe, and 4-OHPhe were five PAHs metabolites most commonly studied in existing studies in children, and their total exposure levels were 0.38 ± 0.98, 2.32 ± 4.83, 0.81 ± 1.54, 0.09 ± 0.14, 0.03 ± 0.10 μmol/mol creatinine, respectively. The meta-analysis showed that the levels of 1-OHPyr were higher in higher environmental exposure group (SMD = 0.21, 95% CI = 0.03~0.40), ETS exposure group (SMD = 0.31, 95% CI = 0.08~0.54), and 6~11 years group (SMD = 0.16, 95% CI = 0.09~0.24); the level of 2-OHNap (SMD = 0.27, 95% CI = 0.01~0.53) was higher in higher environmental exposure group; however, the levels of 3-OHPhe (SMD = − 0.34, 95% CI = − 0.57~− 0.12) and 4-OHPhe (SMD = − 0.48, 95% CI = − 0.69~− 0.28) were higher in lower environmental exposure group. The levels of 1-OHPyr (SMD = − 0.01, 95% CI = − 0.11~0.10) and 2-OHNap (SMD = 0.01, 95% CI = − 0.20~0.22) were not statistically different between boys and girls. In conclusions, we found that the internal diversity of PAHs existed in children and adolescents, and the level of 1-OHPyr in children and adolescents was in higher status compared with non-occupational people who do not smoke.

Synergistic increase of oxidative stress and tumor markers in PAH-exposed workers

In this study, we investigated oxidative stress and tumor marker levels of polycyclic aromatic hydrocarbons (PAHs) in 136 coke oven workers and in 60 control subjects, and evaluated the correlation between oxidative stress and tumor marker levels. Questionnaires on basic demographic information were also administered. Significant differences in employment time and percentages of alcohol drinkers were observed between the control and exposed groups. PAH exposure was assessed using urinary 1-hydroxy-pyrene (1-OHP) levels and was found to be significantly higher in workers than in the controls. Significant differences (P<0.001) of MDA, GST, LDH, NSE, Cyfra21-1, and of SCC and TNF-a (P<0.0001 and P<0.05, P<0.001, respectively) levels were observed among controls and coke-oven workers, except for bottom coke oven workers. Associations between age and risk of increased TNF-a, smoking and increased GST activities, and drinking with increased MDA concentrations, were marginal (P=0.055, P=0.048, P=0.057, respectively). The association between smoking with MDA (P=0.004), NSE (P=0.005), SCC (P=0.004) and TNF-a (P<0.001), and drinking with TNF-a levels was significant (P=0.012). In addition, a significant positive correlation between oxidative stress and tumor markers was found in the present study. These results suggest that a synergistic increase of oxidative stress and tumor markers induced by PAHs may play a role in toxic responses for PAHs in coke oven workers.

Lymphocyte oxidative stress/genotoxic effects are related to serum IgG and IgA levels in coke oven workers

We investigated oxidative stress/genotoxic effects levels, immunoglobulin levels, polycyclic aromatic hydrocarbons (PAHs) levels exposed in 126 coke oven workers and in 78 control subjects, and evaluated the association between oxidative stress/genotoxic effects levels and immunoglobulin levels. Significant differences were observed in biomarkers, including 1-hydroxypyrene levels, employment time, percentages of alcohol drinkers, MDA, 8-OHdG levels, CTL levels and CTM, MN, CA frequency, and IgG, IgA levels between the control and exposed groups. Slightly higher 1-OHP levels in smoking users were observed. For the dose-response relationship of IgG, IgA, IgM, and IgE by 1-OHP, each one percentage increase in urinary 1-OHP generates a 0.109%, 0.472%, 0.051%, and 0.067% decrease in control group and generates a 0.312%, 0.538%, 0.062%, and 0.071% decrease in exposed group, respectively. Except for age, alcohol and smoking status, IgM, and IgE, a significant correlation in urinary 1-OHP and other biomarkers in the total population was observed. Additionally, a significant negative correlation in genotoxic/oxidative damage biomarkers of MDA, 8-OH-dG, CTL levels, and immunoglobins of IgG and IgA levels, especially in coke oven workers, was found. These data suggest that oxidative stress/DNA damage induced by PAHs may play a role in toxic responses for PAHs in immunological functions.

Urinary 1-hydroxypyrene and 8-hydroxydeoxyguanosine levels among coke-oven workers for 2 consecutive days

OBJECTIVES

This study evaluated the levels of exposure to polycyclic aromatic hydrocarbons (PAHs) and their relationship with oxidative DNA damage among Vietnamese coke-oven workers.

METHODS

We collected urine from 36 coke-oven workers (exposed group) at the beginning and end of the shift on 2 consecutive days. We also collected urine from 78 medical staff (control group). Information was collected by questionnaire about smoking status, drinking habit, and working position. Urinary 1-hydroxypyrene (1-OHP) and 8-hydroxydeoxyguanosine (8-OH-dG) were measured using HPLC. All statistical analyses were performed with SPSS version 19.

RESULTS

Urinary 1-OHP was significantly higher in the coke-oven workers than in the control group (p<0.05). Top-oven workers had the highest levels of internal exposure to PAHs, followed by side-oven and then bottom-oven workers (5.41, 4.41 and 1.35 ng/mg creatinine, respectively, at the end of the shift on day 2). Urinary 8-OH-dG was significantly higher in top- and side-oven workers at the end of the shift on day 2 (4.63 and 5.88 ng/mg creatinine, respectively) than in the control group (3.85 ng/mg creatinine). Based on a multi-regression analysis, smoking status had a significant effect on urinary 8-OH-dG (p=0.049). Urinary 1-OHP tended to have a positive correlation with urinary 8-OH-dG (p=0.070).

CONCLUSIONS

Vietnamese coke-oven workers were exposed to PAHs during their work shift. Urinary 1-OHP exceeded the recommended limit, and elevated oxidative DNA damage occurred in top- and side-oven workers on the second day of work. A tendency for positive correlation was found between urinary 1-OHP and urinary 8-OH-dG.

Investigation of polycyclic aromatic hydrocarbon level in blood and semen quality for residents in Pearl River Delta Region in China

This study is the first one investigating the correlation between the concentration of polycyclic aromatic hydrocarbon (PAHs) in blood and semen qualities for residents in the Pearl River Delta (PRD) region in China. Blood samples from 53 infertile volunteers were studied for measures of semen quality and 16 PAHs. Information on the study subjects' living habits (such as smoking, drinking and preference of consumption for food) and general information (age, body-mass-index (BMI) and educational background) were also collected. Statistical results showed that age and BMI were significantly and negatively related to semen motilities. The total concentrations of PAHs (∑16 PAHs) in the blood were 12,010, 7493, 9105 and 8647ng/g for factory workers, office workers, technicians and salespersons, respectively. In addition, ∑16 PAHs in the blood of smokers, drinkers and heavy-taste food consumers were 11,950, 11,266 and 12,141ng/g, which were higher than those observed in nonsmokers (10,457ng/g), nondrinkers (10,920ng/g) and light-taste food consumers (9202ng/g), individually. Furthermore, the Pearson correlation analysis results showed significant positive correlations between BMI and ∑16 PAHs in the blood. Statistically significant correlations were observed between semen motilities and ∑16 PAHs in the blood as well. Logistic regression results showed that for each 1ng/g increase in ∑16 PAHs in blood samples, the log odds of experiencing a pregnancy decrease by 0.039 on average. However, more evidences are needed to clarify the impact of PAHs in the blood to male infertility.

The effect of occupational exposure to benzo[a]pyrene on neurobehavioral function in coke oven workers

BACKGROUND

Coke oven workers are regularly exposed to polycyclic aromatic hydrocarbons (PAHs). Benzo[a]pyrene (B[a]P), known as an indicator species for PAH contamination, is a neurobehavioral toxicant. The purpose of the study was to evaluate the relationship between B[a]P exposure, a B[a]P-related urinary metabolite and neurobehavioral function among coke oven workers.

METHODS

Coke oven workers and oxygen factory workers participated in this study. B[a]P exposure was monitored by air sampling pump, and urinary 1-hydroxypyrene (1-OHP) level was detected with high performance liquid chromatography (HPLC). A questionnaire and the neurobehavioral core test battery (NCTB) were administered to all subjects.

RESULTS

B[a]P-exposed workers were found to have higher urinary 1-OHP levels and worse NCTB performances on eight items than control workers. B[a]P concentrations were higher in the coke oven plant than that in the controls' workplace. The performances on simple reaction time, correct pursuit aiming, and error pursuit aiming decreased with increasing airborne B[a]P in coke oven workers. There were significant correlations between urinary 1-OHP level and six items of the NCTB.

CONCLUSIONS

Occupational exposure to B[a]P is associated with neurobehavioral function impairment in coke oven workers.

Household air pollution: a call for studies into biomarkers of exposure and predictors of respiratory disease

Household air pollution (HAP) from indoor burning of biomass or coal is a leading global cause of morbidity and mortality, mostly due to its association with acute respiratory infection in children and chronic respiratory and cardiovascular diseases in adults. Interventions that have significantly reduced exposure to HAP improve health outcomes and may reduce mortality. However, we lack robust, specific, and field-ready biomarkers to identify populations at greatest risk and to monitor the effectiveness of interventions. New scientific approaches are urgently needed to develop biomarkers of human exposure that accurately reflect exposure or effect. In this Perspective, we describe the global need for such biomarkers, the aims of biomarker development, and the state of development of tests that have the potential for rapid transition from laboratory bench to field use.

The influence of metabolic gene polymorphisms on urinary 1-hydroxypyrene concentration in Thai bus drivers

Polycyclic aromatic hydrocarbons (PAHs) are associated with an increased cancer risk. CYP1A1 and GSTs enzymes are important in metabolism of PAHs. Genetic polymorphisms of these enzymes are responsible for enzyme activity and concentration variation. The objectives of this study were to evaluate association of 1-OHP concentration with genetic polymorphisms of CYP1A1 and GSTs in Thai bus drivers. The results showed that 1-OHP levels in bus drivers were significantly higher than that in the control group. Significant difference in 1-OHP was found between smokers and non-smokers, in only bus drivers. Significantly increasing of 1-OHP levels were observed in bus drivers with CYP1A1 MspI and exon 7 variants. Whereas, bus drivers with GSTP1 Val and GSTM1 null genotypes showed decreasing in excretion of 1-OHP. No association between 1-OHP and polymorphisms of GSTT1 was found. This study indicated that 1-OHP concentrations were associated with exposure to air pollution, cigarette smoking and polymorphisms of CYP1A1, GSTM1 and GSTP1 genes.

Association of aryl hydrocarbon receptor gene polymorphisms and urinary 1-hydroxypyrene in polycyclic aromatic hydrocarbon-exposed workers

Polycyclic aromatic hydrocarbons (PAH) in coke oven emissions could cause lung cancer in human. Individual's genotype of the metabolic enzymes and early biological changes were known to be associated with the susceptibility of cancer development. Knowledge of metabolic gene polymorphisms, which affect on the urinary 1-hydroxypyrene (1-OHP), could benefit us in understanding the interindividual difference in the mechanism of PAH-induced carcinogenesis. In this study, we investigated the association of aryl hydrocarbon receptor (AhR) gene polymorphisms and urinary 1-OHP. One hundred forty-seven workers exposed to PAH and 69 nonexposure workers were recruited. Seven tagging single nucleotide polymorphisms in AhR gene were selected by pariwise r(2) method and minor allele frequency cutoff of 0.05 from Chinese genotype data in HapMap project. These seven tagging single nucleotide polymorphisms were genotyped by PCR-based methods. Multivariate analysis of covariance revealed that the levels of 1-OHP in PAH-exposed workers carrying genotype CT were lower than workers carrying wild genotype TT at loci rs10250822 and rs2282885 of AhR gene (P = 0.032 and 0.044, respectively). In PAH-exposed workers, the urinary 1-OHP levels showed a linear correlation (P(trend) = 0.041) with the genotypes at locus rs2282885, especially in low and moderate exposure groups. In contrast, no significant association was found between urinary 1-OHP level and AhR genotypes among nonexposed workers. Our findings indicated that polymorphisms of AhR gene were associated with the level of 1-OHP among PAH-exposed workers, suggesting that AhR-mediated signaling might contribute to individual susceptibility to PAH exposure.

Effects of benzo[a]pyrene on autonomic nervous system of coke oven workers

Objectives are to investigate the effects of benzo[a]pyrene (B[a]P) on the autonomic nervous system of coke oven workers. One hundred eighty-four coke oven workers were divided into 3 groups according to their working sites (coke oven bottom group, coke oven side group and coke oven top group), and 93 referents were recruited. B[a]P monitored by air sampling pumps as well as urinary 1-hydroxypyrene (1-OH-Py) was determined by high performance liquid chromatograph with a fluorescence detector (HPLC-FD). The autonomic nervous system (ANS) function was determined by 4 tests: Valsalva Manoeuvre heart rate variation (HR-V), variation of heart rate when breathing deeply (HR-DB), variation of heart rate when instantly standing up (HR-IS, including RR30:15 and RRmax:min) and variation of blood pressure when instantly standing up (BP-IS). The B[a]P mean concentrations in coke oven bottom, coke oven side and coke oven top were 19, 185 and 1,623 ng/m(3), respectively. The levels of urinary 1-OH-Py were markedly higher in the 3 exposed groups than that in the referent group (p<0.01). No significant difference was found in each group between smokers and non-smokers (p>0.05). Compared with referents, HR-V decreased significantly in coke oven workers (p<0.01), representing modulation of parasympathetic nervous function. However, no statistical differences were found in HR-DB, RR30:15, RRmax:min and BP-IS between the exposed groups and the control group (p>0.05). HR-V decreased with the increment of 1-OH-Py (p<0.05), and results of multiple linear stepwise regression demonstrated that external exposure level and duration of education entered the HR-V model; age was a significant factor of HR-DB and RRmax:min, but no variable was involved in RR30:15 and BP-IS regression. Benzo[a]pyrene affects the autonomic nervous function of coke oven workers mainly by down-regulating the parasympathetic nervous function.

Using lymphocyte and plasma Hsp70 as biomarkers for assessing coke oven exposure among steel workers

BACKGROUND

Hsp70, an early-response protein induced when organisms are confronted with simple or complicated environmental stresses, can act as either a cellular protector or a danger signal.

OBJECTIVES

The goal of this study was to evaluate levels of lymphocyte and/or plasma Hsp70 as biomarkers for assessing exposure response to complex coke oven emissions (COEs).

METHODS

We recruited 101 coke oven workers and determined levels of polycyclic aromatic hydrocarbon (PAH) exposure, urinary 1-hydroxypyrene (1-OHP), genotoxic damage by comet assay and micronuclei test, and other markers of damage, including plasma malondialdehyde (MDA) and lactate dehydrogenase (LDH). These were compared to levels of lymphocyte (intra-cellular) and plasma (extracellular) Hsp70 using Western blots and enzyme-linked immunosorbent assays (ELISA), respectively.

RESULTS

We observed a COEs-related dose-dependent increase in levels of DNA damage, micronuclei rate, MDA concentration, and LDH activity. Lymphocyte Hsp70 levels increased in the intermediate-exposure group (1.39 +/- 0.88) but decreased in the high-exposure group (1.10 +/- 0.55), compared with the low-exposure group. In contrast, plasma Hsp70 levels progressively increased as the dose of exposure increased. Negative correlations were seen between lymphocyte Hsp70 levels and olive tail moment and LDH activity in the intermediate- and high-exposure groups. However, we observed positive correlations between plasma Hsp70 levels and LDH activity in the low and intermediate groups.

CONCLUSIONS

In workers exposed to COEs, high lymphocyte Hsp70 levels may provide protection and high plasma Hsp70 levels may serve as a danger marker. Larger validation studies are needed to establish the utility of Hsp70 as a response marker.

Past and future applications of CYP450-genetic polymorphisms for biomonitoring of environmental toxicants

Cytochrome P450s (CYPs) are a huge gene superfamily of heme enzymes involved in xenobioitc as well as endobiotic metabolism. They play a critical role in adaptation to environmental changes for survival of living organisms. In addition, the huge environmental loads of human-made chemicals are biotransformed into bioactive or detoxified forms by CYPs. Thus, CYPs have been used for biomonitoring of environmental pollutants, screening of their metabolisms and exploring remedy. In particular, the induction or inhibition of CYPs has been applied to exposure monitoring of environmental toxicants, which are biotransformed by CYPs. This review considers past and future applications of CYP-genetic polymorphisms as susceptibility biomarkers for biomonitoring. Furthermore, we suggest the needs for further understanding of the characteristics of each CYP isozyme, consideration of real-life exposures such as mixed contamination with various chemicals, and incorporation of the presence of other phase I and phase II enzymes, for proper applications of CYP polymorphisms on biomonitoring.

Urinary 1-hydroxypyrene concentrations in Chinese coke oven workers relative to job category, respirator usage, and cigarette smoking

BACKGROUND

1-Hydroxypyrene (1-OHP) is a biomarker of recent exposure to polycyclic aromatic hydrocarbons (PAHs). We investigated whether urinary 1-OHP concentrations in Chinese coke oven workers (COWs) are modulated by job category, respirator usage, and cigarette smoking.

METHODS

The present cross-sectional study measured urinary 1-OHP concentrations in 197 COWs from Coking plant I and 250 COWs from Coking plant II, as well as 220 unexposed referents from Control plant I and 56 referents from Control plant II.

RESULTS

Urinary 1-OHP concentrations (geometric mean, micromol/mol creatinine) were 5.18 and 4.21 in workers from Coking plants I and II, respectively. The highest 1-OHP levels in urine were found among topside workers including lidmen, tar chasers, and whistlers. Benchmen had higher 1-OHP levels than other workers at the sideoven. Above 75% of the COWs exceeded the recommended occupational exposure limit of 2.3 micromol/mol creatinine. Respirator usage and increased body mass index (BMI) slightly reduced 1-OHP levels in COWs (P < 0.1). Cigarette smoking significantly increased urinary 1-OHP levels in unexposed referents (P < 0.005), but had no effect in COWs (P > 0.1).

CONCLUSIONS

Chinese COWs, especially topside workers and benchmen, are exposed to high levels of PAHs. Urinary 1-OHP concentrations appear to be modulated by respirator usage and BMI in COWs, as well as by smoking in unexposed referents.

The influence of metabolic gene polymorphisms on urinary 1-hydroxypyrene concentrations in Chinese coke oven workers

Urinary 1-hydroxypyrene (1-OHP), a biomarker of polycyclic aromatic hydrocarbons (PAHs) exposure, may be influenced by metabolic gene polymorphisms. Such knowledge could benefit us in understanding the inter-individual difference in the mechanism of PAHs-induced carcinogenesis. We investigated the influence of gene polymorphisms on urinary 1-OHP concentrations in 447 coke oven workers from two coking plants in south China. After adjustment for age, plant, level of occupational exposure, body mass index, level of education, alcohol consumption, cigarette smoking and respirator usage, AhR R554K (rs2066853), UGT1A1 -3263T>G (rs4124874) and GSTP1 I105V (rs1695) were associated with urinary 1-OHP excretion with the p-value of 0.053, 0.006 and 0.021, respectively. The concentrations of urinary 1-OHP (Geometric mean, micromol/mol creatinine) in the homozygous major variant carriers and homozygous minor variant carriers for AhR R554K, UGT1A1 -3263T>G and GSTP1 I105V were listed as follows: 4.20 and 5.12, 5.11 and 3.92, 4.93 and 2.91, respectively. GSTT1 present carriers had a significantly higher urinary 1-OHP level than that in null carriers in the case with AhR R554K GA/AA carriers (5.17 vs. 3.64 micromol/mol creatinine, p=0.038), as well as in the case with UGT1A1 -3263T>G TG/GG carriers (5.67 vs. 3.38 micromol/mol creatinine, p=0.001). These results showed that AhR, UGT1A1, GSTP1 and GSTT1 polymorphisms were associated with urinary 1-OHP concentrations in Chinese coke oven workers. No influence was found in the association between urinary 1-OHP and other genetic polymorphisms such as CYP1A1, CYP1A2, CYP1B1, CYP2E1, EPHX1, EPHX2 in this population.

Path Analysis of Biomarkers of Exposure and Early Biological Effects among Coke-Oven Workers Exposed to Polycyclic Aromatic Hydrocarbons

Many host factors or biomarkers are involved in the process of early DNA damage induced by occupational exposure to polycyclic aromatic hydrocarbons (PAH) as seen in coke-oven workers. This paper aimed to identify complicated causal interrelationship of various biomarkers using the path analysis. In this analysis, we included 235 subjects (166 coke-oven workers and 69 nonexposed controls) whose data on the comet assay (e.g., Olive tail moment) and cytogenetic analysis of peripheral blood lymphocytes as well as urinary 1-hydroxypyrene (1-OHP) were available. The path analysis showed that coke-oven exposure and tobacco smoke were both significant predictors of the concentrations of urinary 1-OHP (P < 0.05), with a coefficient of determination of 0.75. The factors having significant influence on the Olive tail moment were in the following order: urinary 1-OHP > XRCC1-exon 9 variant genotype > ERCC2-exon 10 variant genotype > XRCC1-exon 6 variant genotype, with a coefficient of determination of 0.22. The variables of relative importance in influencing on cytokinesis-block micronucleus frequencies were in the following order: coke-oven exposure > urinary 1-OHP > age > mEH3 variant genotype > ERCC2-exon 10 variant genotype > XRCC1-exon 6 variant genotype, with a coefficient of determination of 0.27. These results indicated that exogenous agents, especially the coke-oven exposure, played a more important role than the genotypes in the induction of early genetic damage. In conclusion, the path analysis seemed to be an alternative statistical approach for the ascertainment of complicated association among related biomarkers for the assessment of occupational exposure.

Effect of Urban Traffic, Individual Habits, and Genetic Polymorphisms on Background Urinary 1-Hydroxypyrene Excretion

PURPOSE

Potential sources of exposure to polycyclic aromatic hydrocarbons (PAHs) and genetic polymorphisms were investigated in relation to their contribution to interindividual variation in baseline levels of urinary 1-hydroxypyrene (1-OHP) excretion in subjects without occupational exposure to PAHs.

METHODS

Urinary excretion of 1-OHP was measured in 114 subjects, including 48 women and 66 men. Questionnaire information was collected on possible environmental and individual sources of PAH exposure. A subset of 70 individuals also was evaluated for a single-nucleotide polymorphism (Ex7+295C-->T) in the cytochrome P-450 1A2 (CYP1A2) gene, and 61 of these also were evaluated for the glutathione transferase T1 (GSTT1) gene polymorphism.

RESULTS

1-OHP values did not show a significant seasonal variability and were unaffected by age; education; body mass index; smoking status, including passive smoking; or the C-->T base substitution in position 295 of exon 7 of the CYP1A2 gene. After reciprocal adjustment with logistic regression, living in a heavily trafficked urban area (odds ratio, 4.9; 95% confidence interval, 1.0-24.9), and frequent intake of grilled meat (odds ratio, 6.9; 95% confidence interval, 1.1-43.5) were significant predictors of background urinary 1-OHP levels of 0.50 microg/g creatinine or greater. Elevated risks also were associated with daily alcohol intake greater than 65 g and the nonnull GSTT1 genotype.

CONCLUSION

Our study shows that exposure to urban traffic, dietary habits, and the nonnull GSTT1 genotype may contribute to interindividual variation in background levels of 1-OHP urinary excretion in subjects without occupational exposure to PAHs.

Associations Between Exposure to Polycyclic Aromatic Hydrocarbons and Temporal Change of Urinary 1-Hydroxypyrene Levels in Taiwanese Coke-Oven Workers

OBJECTIVES

Our aim is to analyze the association between polycyclic aromatic hydrocarbon (PAH) exposure and the temporal change of urinary 1-hydroxypyrene (1-OHP).

METHODS

Two personal air samples, eight spot urine samples, and questionnaires were used to collect PAH exposure, urinary 1-OHP, demographic data, and environmental pollutants.

RESULTS

Topside-oven workers had significantly higher levels of PAH exposure and 1-OHP than side-oven workers. Urinary 1-OHP was a biomarker for PAH exposure. In topside-oven workers, the trend of 1-OHP increased sharply and reached the top in the sixth day after work and declined dramatically on days off. In side-oven workers, such a trend was not found, and those who smoked showed a slight increase in urinary 1-OHP levels on days off.

CONCLUSIONS

We suggest that the pattern of temporal change of urinary 1-OHP levels is different between topside-oven and side-oven workers.

Occupational exposure to polycyclic aromatic hydrocarbons in German industries: association between exogenous exposure and urinary metabolites and its modulation by enzyme polymorphisms

A cross-sectional study was conducted in 170 German workers exposed to polycyclic aromatic hydrocarbons (PAH) to investigate the role of 11 polymorphisms of CYP1A1, CYP1A2, CYP1B1, CYP3A4, EPHX1, GSTM1, GSTT1, and GSTP1 in the association between occupational exposure to PAH and urinary PAH metabolites. Polymorphisms were genotyped with real-time PCR. Exposure to 16 PAH was measured by personal air sampling. Urinary concentrations of 1-hydroxypyrene (1-OHP) and the sum of 1-, 2+9-, 3-, and 4-hydroxyphenanthrenes (OHPhe) were determined post-shift. Urinary 1-OHP and OHPhe correlated significantly with exogenous pyrene (Spearman r=0.52, p<0.0001) and phenanthrene (Spearman r=0.72, p<0.0001), respectively. ANCOVA was applied to investigate potential predictors of the metabolite levels. Current smoking and type of industry turned out to be predictors of 1-OHP but not of OHPhe. CYP1A1 3801TC carriers showed 1.6-fold higher OHPhe levels than 3801TT carriers (p=0.03). EPHX1 113HH was associated with higher and 139RR with lower metabolite levels when compared with the corresponding reference genotypes (113YY; 139HH). In comparison to GSTP1 114AA, carriers of the V allele had 1.5-fold higher 1-OHP (p=0.03) and 2-fold higher OHPhe concentrations (p=0.001). OHPhe turned out to be also a suitable biomarker of occupational PAH exposure. The association with ambient PAH exposure and the influence of polymorphisms was more pronounced for OHPhe.

Effects of Genetic Polymorphisms of Metabolic Enzymes on Cytokinesis-Block Micronucleus in Peripheral Blood Lymphocyte among Coke-Oven Workers

Exploring the associations between genetic polymorphisms of metabolic enzymes and susceptibility to polycyclic aromatic hydrocarbon (PAH)–induced chromosomal damage is of great significance for understanding PAH carcinogenesis. Cytochrome P450, glutathione S-transferase, microsomal epoxide hydrolase, NAD(P)H:quinone oxidoreductase, and N-acetyltransferase are PAH-metabolizing enzymes. In this study, we genotyped for the polymorphisms of these genes and assessed their effects on cytokinesis-block micronucleus (CBMN) frequencies in peripheral blood lymphocytes among 141 coke-oven workers and 66 non–coke-oven worker controls. The geometric means of urinary 1-hydroxypyrene levels in coke-oven workers and the controls were 12.0 and 0.7 μmol/mol creatinine, respectively (P &lt; 0.01). The CBMN frequency (number of micronuclei per 1,000 binucleated lymphocytes) was significantly higher in coke-oven workers (9.5 ± 6.6‰) than in the controls (4.0 ± 3.6‰; P &lt; 0.01). Among the coke-oven workers, age was positively associated with CBMN frequency; the mEH His113 variant genotype exhibited significantly lower CBMN frequency (8.5 ± 6.5‰) than did the Tyr113/Tyr113 genotype (11.3 ± 6.4‰; P &lt; 0.01); the low mEH activity phenotype exhibited a lower CBMN frequency (8.6 ± 6.8‰) than did the high mEH activity phenotype (13.2 ± 6.7‰; P = 0.01); the GSTP1 Val105/Val105 genotype exhibited a higher CBMN frequency (15.0 ± 5.8‰) than did the GSTP1 Ile105/Ile105 or Ile105/Val105 genotypes (9.3 ± 6.5‰; P &lt; 0.01); the joint effect of high mEH activity phenotype and GSTM1 null genotype on CBMN frequencies was also found. Gene-environment interactions between occupational PAH exposure and polymorphisms of mEH and/or GSTM1 were also evident. These results indicate that the mEH, GSTP1, and GSTM1 polymorphisms may play a role in sensitivity or genetic susceptibility to the genotoxic effects of PAH exposure in the coke-oven workers.

Lack of modulating influence of GSTM1 and GSTT1 polymorphisms on urinary biomonitoring markers in coke-oven workers

BACKGROUND

Coke-oven workers (COWs) are occupationally exposed to high concentrations of polycyclic aromatic hydrocarbons (PAHs). Urinary 8-hydroxy-2-deoxyguanosine (8-OH-dG) and 1-hydroxypyrene (1-OHP) are biological markers of oxidative DNA damage and PAHs metabolism, respectively. In this study, we investigated whether polymorphisms of glutathione S-transferase (GSTM1 and GSTT1) can modulate the relationship between urinary 8-OH-dG and 1-OHP concentrations among the COWs.

METHODS

This was a cross-sectional study. Between February and November of 2001, 53 topside-oven and 130 side-oven workers with the presence of GSTM1 and GSTT1 genotypes were investigated.

RESULTS

Urinary 1-OHP and 8-OH-dG concentrations (mean +/- SD) in the topside-oven workers with the presence of GSTM1 were 107.2 +/- 107.9 and 15.3 +/- 9.7 ng/ml, respectively, which were not significantly different from those in the absence of GSTM1 (84.1 +/- 104.5 and 12.8 +/- 14.1 ng/ml). The similar insignificant results were also noted in the sideoven workers. For GSTT1 polymorphism, the results remained insignificant. In contrast, individual excretion of urinary 8-OH-dG and 1-OHP concentrations were still highly correlated (Spearman correlation coefficients: r = 0.43, P < 0.0001, n = 183).

CONCLUSIONS

GST may not play a role in the regulation of metabolism of urinary biological markers in COWs.

Association between urinary 1-hydroxypyrene and genotoxic effects in coke oven workers

AIMS

To investigate whether current occupational exposure of coke oven workers to polycyclic aromatic hydrocarbons (PAHs) results in genotoxic effects measured in peripheral blood lymphocytes and whether these biomarkers are associated with the biomarkers of exposure.

METHODS

Blood and urine samples were collected immediately after a shift at the end of a working week from 50 coke oven workers and 50 control workers not exposed to PAHs. Methods included: (1) biomarkers of exposure: urinary 1-hydroxypyrene (HpU), urinary mutagenicity by the plate Salmonella test with strains TA98 and YG1024 after metabolic activation, expressed as mutagenic rate (MR98 and MR1024, respectively), urinary cotinine; and (2) biomarkers of biological effects in peripheral blood lymphocytes (PBL): sister chromatid exchanges (SCE/cell), cells of high frequency of SCE (% HFC), micronuclei (MN/1000 cells), chromosomal aberrations (CA/100 cells), and DNA damage by the Comet assay.

RESULTS

Occupational exposure to PAH resulted in significantly increased levels of HpU and mutagenic effect of urine. Median values of these biomarkers in coke oven workers were: 9.0 micromol/mol creatinine for HpU, 2.7 for MR98, and 8.2 for MR1024, compared to the controls: HpU = 0.6 micromol/mol creatinine, MR98 = 1.2, and MR1024 = 5.5. Occupational exposure caused significant induction of SCE, HFC, and MN in coke oven workers: median SCE = 5.9, HFC = 12.0%, MN = 6.0 compared to the controls: 3.9, 5.0%, and 3.0, respectively. No effect of occupational exposure was found in relation to CA and DNA damage measured with the Comet assay. HpU concentration was positively associated with SCE and HFC. The concentration of urinary 1-hydroxypyrene corresponding to a 5% probability of increased SCE was 1.0 micromol/mol creatinine.

CONCLUSIONS

The occupational exposure to PAHs resulted in measurable biological effects (SCE, HFC, MN). In coke oven workers an increased level of SCE was not observed below the level of 1.0 micromol HpU/mol creatinine.

Air concentrations and urinary metabolites of polycyclic aromatic hydrocarbons among paving and remixing workers

The exposure of paving workers to polycyclic aromatic hydrocarbons (PAH) during stone mastic asphalt (SMA) paving and remixing was evaluated. The effects on the workers' PAH exposure were also evaluated during the use of an industrial by-product, coal fly ash (CFA), instead of limestone as the filler in the SMA. The PAH exposure was measured by personal air sampling and by analysing the levels of urinary naphthols, phenanthrols and 1-hydroxypyrene (1-OHP) in the workers' pre- and post-shift urine samples. The respiratory PAH exposure of the paving workers (geometric mean (GM) 5.7 microg m(-3)) was about ten-fold that of the traffic controllers (GM 0.43 microg m(-3)). The levels of PAH metabolites were significantly higher (p < 0.05) in the post-shift urine samples than in the pre-shift urine samples, and the levels of metabolites in the post-shift urine of paving workers were significantly higher than in that of the controls (p < 0.01). Urinary 1-naphthol correlated well with the airborne concentrations of the two- to three-ring PAHs (r = 0.544, p = 0.003) and naphthalene (r = 0.655, p < 0.001), when non-smoking paving workers were tested. A good correlation was observed between urinary 1-OHP and the airborne concentrations of the four- to six-ring PAHs (r = 0.524, p = 0.003) as well as total PAHs (r = 0.575, p = 0.001). The concentrations of 1-OHP and phenanthrols in the urine of the pavers were significantly higher (p < 0.01) during remixing than during SMA paving. The CFA in the asphalt had no effect on the airborne PAH exposure or on the concentrations of the PAH metabolites in the paving workers' urine.