RESUMEN
Exposure to polycyclic aromatic hydrocarbons (PAH) and DNA damage were analyzed in coke oven (n = 37), refractory (n = 96), graphite electrode (n = 26), and converter workers (n = 12), whereas construction workers (n = 48) served as referents. PAH exposure was assessed by personal air sampling during shift and biological monitoring in urine post shift (1-hydroxypyrene, 1-OHP and 1-, 2 + 9-, 3-, 4-hydroxyphenanthrenes, SigmaOHPHE). DNA damage was measured by 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and DNA strand breaks in blood post shift. Median 1-OHP and SigmaOHPHE were highest in converter workers (13.5 and 37.2 microg/g crea). The industrial setting contributed to the metabolite concentrations rather than the air-borne concentration alone. Other routes of uptake, probably dermal, influenced associations between air-borne concentrations and levels of PAH metabolites in urine making biomonitoring results preferred parameters to assess exposure to PAH. DNA damage in terms of 8-oxo-dGuo and DNA strand breaks was higher in exposed workers compared to referents ranking highest for graphite-electrode production. The type of industry contributed to genotoxic DNA damage and DNA damage was not unequivocally associated to PAH on the individual level most likely due to potential contributions of co-exposures.
Asunto(s)
Contaminantes Ocupacionales del Aire/toxicidad , Daño del ADN , Exposición Profesional/análisis , Hidrocarburos Policíclicos Aromáticos/toxicidad , Adulto , Contaminantes Ocupacionales del Aire/análisis , Biomarcadores/metabolismo , Coque/análisis , Alemania , Humanos , Industrias/estadística & datos numéricos , Persona de Mediana Edad , Exposición Profesional/estadística & datos numéricos , Fenantrenos/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Pirenos/análisis , Adulto JovenRESUMEN
Polycyclic aromatic hydrocarbons (PAH) are metabolized in a complex manner. Although biological activity is associated with diol-epoxide formation, phenolic metabolites have predominantly been used in human biomonitoring. In this study monohydroxylated and new metabolites were characterized as biomarkers for occupational PAH exposure. In 97 male workers, personal exposure to 16 airborne PAH compounds was measured during shift. In postshift urine, 1-hydroxypyrene and 1,6- and 1,8-dihydroxypyrene (1-OHP, DiOHP) were determined as metabolites of pyrene (P), and the sum of 1-, 2-, 3-, 4-, and 9-hydroxyphenanthrenes (OHPHE), and PHE-dihydrodiols (PHED) as metabolites of phenanthrene (PHE). The referent group comprised 21 nonsmoking construction workers. Median (interquartile range) shift concentrations of airborne P and PHE were 1.46 (0.62-4.05 microg/m(3)) and 10.9 (3.69-23.77 microg/m(3)), respectively. The corresponding parameters were 3.86 (2.08-7.44) microg/g creatinine (crn) for 1-OHP, 0.66 (0.17-1.65) microg/g crn for DiOHP, 11.44 (5.21-34.76) microg/g crn for OHPHE, and 12.28 (3.3-97.76) microg/g crn for PHED in PAH-exposed workers. The median levels of 1-OHP and OHPHE were 0.09 (0.08-0.17 microg/m(3)) and 0.59 (0.45-1.39 microg/m(3)), respectively, in the referents. PHE correlated significantly with OHPHE and PHED, and P with 1-OHP but not with DiOHP. Under a doubling of PHE, OHPHE increased by a factor of 1.56 and PHED by 1.57. With a doubling of P, 1-OHP rose by 1.31 and DiOHP by 1.27. P is predominantly metabolized into 1-OHP, whereas PHE is metabolized equally into OHPHE and PHED. Thus metabolites of PHE were found as reliable biomarkers for PAH exposure.
Asunto(s)
Contaminantes Ocupacionales del Aire/orina , Biomarcadores/orina , Monitoreo del Ambiente/métodos , Exposición Profesional/análisis , Hidrocarburos Policíclicos Aromáticos/orina , Adulto , Estudios Transversales , Monitoreo del Ambiente/instrumentación , Alemania , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Human 8-oxoguanine DNA glycosylase 1 (hOGG1) plays an important role in the repair of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodGuo), one of the major constituents in DNA damage. A recent in vitro study showed that the hOGG1 326Cys polymorphism (rs1052133) exhibits reduced 8-oxodGuo repair activity. This study aimed to develop a LightCycler (LC) assay to analyze the C>G polymorphism (Ser326Cys) in exon 7 of the hOGG1 gene followed by validation of the method using DNA samples from 260 polycyclic aromatic hydrocarbons(PAH)-exposed workers with known 8-oxodGuo DNA-adduct values measured by HPLC. Twenty DNA samples were analyzed by a PCR-RFLP analysis with Fnu4H I to generate control DNA. LC melting curve analyses of the hOGG1 exon 7 PCR product were characteristic of the probes hybridized to the non-mutated Ser-type (CC) at 65 degrees C, or to the Cys mutant (GG) at 59 degrees C. The distribution in the population of PAH-exposed workers (N=260) was 58% (CC), 38%(CG), and 4% (GG). The minor G allele displayed a frequency of 23 %. The distribution of 8-oxodGuo adducts for the Ser326Cys variants of hOGG1 revealed geometric means (GM) of 5.83 (CC), 5.27 (CG), and 6.53 (GG) 8-oxodGuo adducts/10(6)dGuo. Corresponding GM values of current smokers were 5.7 (CC), 5.6 (CG) and 7.0 (GG) 8-oxodGuo adducts/10(6) dGuo. The analysis of the Ser326Cys polymorphism in 260 DNA samples with this new LC assay revealed that this method is reliable for high throughput analysis of this key polymorphism in the hOGG1 gene.
Asunto(s)
ADN Glicosilasas/genética , Reacción en Cadena de la Polimerasa , Polimorfismo de Nucleótido Simple/genética , Adulto , Daño del ADN/efectos de los fármacos , ADN Glicosilasas/metabolismo , Reparación del ADN/genética , Regulación Enzimológica de la Expresión Génica , Humanos , Masculino , Persona de Mediana Edad , Exposición Profesional/efectos adversos , Hidrocarburos Policíclicos Aromáticos/efectos adversos , Reacción en Cadena de la Polimerasa/instrumentación , Factores de TiempoRESUMEN
In regulatory toxicology, the dose-response relationship between occupational exposure and biomarkers is of importance in setting threshold values. We analyzed the relationships between occupational exposure to polycyclic aromatic hydrocarbons (PAH) and various biomarkers of internal exposure and DNA damage with data from 284 highly exposed male workers. Personal exposure to phenanthrene and other PAHs was measured during shift and correlated with the sum of 1-, 2+9-, 3-, and 4-hydroxyphenanthrenes in post-shift urine. PAHs and hydroxyphenanthrenes were associated with DNA damage assessed in WBC as 8-oxo-7,8-dihydro-2'-deoxyguanosine/10(6) dGuo and strand breaks by Comet assay as Olive tail moment. Hydroxyphenanthrenes correlated with phenanthrene (Spearman r(s) = 0.70; P < 0.0001). No correlations could be found between strand breaks and exposure (r(s) = 0.01, P < 0.0001 for PAHs; r(s) = -0.03, P = 0.68 for hydroxyphenanthrenes). Correlations with 8-oxo-7,8-dihydro-2'-deoxyguanosine/10(6) dGuo were weakly negative (r(s) = -0.22, P = 0.004 for PAHs) or flat (r(s) = -0.08, P = 0.31 for hydroxyphenanthrenes). Linear splines were applied to assess the relationships between the log-transformed variables. All regression models were adjusted for smoking and type of industry. For hydroxyphenanthrenes, 51.7% of the variance could be explained by phenanthrene and other predictors. Up to 0.77 microg/m(3) phenanthrene, no association could be found with hydroxyphenanthrenes. Above that point, hydroxyphenanthrenes increased by a factor of 1.47 under a doubling of phenanthrene exposure (slope, 0.56; 95% confidence interval, 0.47-0.64). Hydroxyphenanthrenes may be recommended as biomarker of occupational PAH exposure, whereas biomarkers of DNA damage in blood did not show a dose-response relation to PAH exposure.
Asunto(s)
Biomarcadores , Carcinógenos Ambientales/toxicidad , Exposición Profesional , Hidrocarburos Policíclicos Aromáticos/toxicidad , Ensayo Cometa , Simulación por Computador , Daño del ADN , Relación Dosis-Respuesta a Droga , Humanos , Industrias , Masculino , Modelos EstadísticosRESUMEN
BACKGROUND: The utility of typing single nucleotide polymorphisms (SNPs) for the determination of the N-acetyltransferase 2 (NAT2) acetylation status is a matter of debate. AIMS OF THE STUDY: Evaluation of the concordance between deduced genotype results of seven human NAT2 SNPs generated by Real-time PCR analysis and human NAT2 phenotypes. METHODS: NAT2 phenotypes of 38 Caucasian workers were determined using a suitable caffeine test method. Genomic DNA aliquots were used for the determination of seven human NAT2-specific SNPs (G191A, C282T, T341C, C481T, G590A, A803G, G857A). RESULTS AND CONCLUSIONS: Phenotypic results based on the molar ratio of 5-acetylamino-6-formylamino-3-methyluracil (AFMU)/(AFMU+1-methlyuric acid (1U)+1-methylxanthine (1X)) calculated from excreted caffeine metabolite levels in urine samples with 0.3 as a cut-off point between slow (<0.3) and rapid acetylators (>or=0.3). Twenty-seven samples belonged to the slow (mean 0.13; range: 0.03-0.25), 11 to the rapid (mean: 0.41; range: 0.34-0.48) acetylators. LightCycler analyses revealed 11 different NAT2 variant combinations, whereby *5B/*5B and *5B/*6A or *5A/*6C (each 21%), were the most frequent. The deduced acetylation status of the seven NAT2 SNPs matched perfectly with the 38 results determined by phenotyping. This study showed a 100% concordance between NAT2 phenotypes and the deduced NAT2 genotypes and the suitability of the high-speed NAT2-specific LightCycler analysis in a Caucasian population.
Asunto(s)
Arilamina N-Acetiltransferasa/genética , Cafeína/metabolismo , Polimorfismo de Nucleótido Simple , Acetilación , Adulto , Arilamina N-Acetiltransferasa/metabolismo , Biotransformación/genética , Cafeína/farmacocinética , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Fenotipo , Reacción en Cadena de la Polimerasa , Uracilo/análogos & derivados , Uracilo/orina , Ácido Úrico/análogos & derivados , Ácido Úrico/orina , Población Blanca , Xantinas/orinaRESUMEN
The major DNA adducts of anti-benzo[a]pyrene diolepoxide (BPDE) were determined by high performance liquid chromatography with fluorescence detection (HPLC-FLD) in white blood cells (WBC) of workers exposed to benzo[a]pyrene (B[a]P). In addition, ambient concentrations of B[a]P at the workplace were determined by personal air sampling. Workers in a refractory setting were examined before (n=26) and 3 months after (n = 33) changing the production material (binding pitch). Furthermore, 9 coke oven workers were examined. The change in the production process in the refractory setting led to a decrease in the median of ambient B[a]P concentrations (0.14 to <0.07 microg/m3). The median of BPDE-DNA adduct levels in WBC also decreased from 0.9 adducts/10(8) nucleotides before changing the production material to <0.5 adducts/10(8) nucleotides 3 months afterwards. The B[a]P concentrations at the workplace for the coke oven workers were found to be significantly higher than in the refractory setting. However, BPDE-DNA adduct concentrations in coke oven workers and refractory setting workers showed no significant difference, which was probably due to the low number of studied subjects in the coke-oven setting. No significant differences could be observed for BPDE-DNA adduct levels between current smokers (n=21) and non-smokers (n=14; p = 0.93) from both plants. In addition, no correlation between B[a]P concentrations in the air and DNA adduct levels in refractory workers and in coke oven workers could be found (r = -0.03, p = 0.87). Because of the missing correlation between personal air sampling and BPDE-DNA adduct levels in WBC, the results may indicate that their formation is either influenced by other routes of exposure to B[a]P (e.g., skin absorption, dietary habits) or interindividual differences in their formation and repair.
Asunto(s)
7,8-Dihidro-7,8-dihidroxibenzo(a)pireno 9,10-óxido/metabolismo , Benzo(a)pireno/farmacología , Coque , Aductos de ADN/efectos de los fármacos , Exposición Profesional , Cromatografía Líquida de Alta Presión , Aductos de ADN/sangre , Alemania , HumanosRESUMEN
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.