Chih-Hong Pan

Polycyclic aromatic hydrocarbon-induced oxidative stress and lipid peroxidation in relation to immunological alteration

Objectives We evaluated the association between exposure to polycyclic aromatic hydrocarbons (PAHs) and immunological measurements using blood samples from coke oven workers exposed to high and low PAH levels. Methods A population-based cross-sectional study was conducted from 2008–2009 with coke oven workers and steel-rolling workers as the exposed and control groups, respectively. Questionnaires on basic demographic information were administered. Personal breathing zone and urine samples were collected to quantify personal PAH intake and biological response doses. Immunological and cytokine parameters in serum were analysed. Urinary malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) were analysed to determine oxidative stress induced by PAHs in relation to altered humoural immunological status. Results Mean levels of serum immunoglobulin A (IgA) and TNF-α were significantly increased in coke oven workers compared to steel-rolling workers who had no or minimal PAH exposure (p=0.0033 and p<0.0001, respectively). There were no significant differences in mean levels of IL-4 and IL-10 between coke oven workers and steel-rolling workers. Moderate activation of lipid peroxidation and oxidative damage as determined by plasma MDA and 8-OHdG levels were detected simultaneously with significant alterations in IgA and IgE levels. Multiple regression analyses demonstrated that PAHs with high molecular weights >252 (dibenzo(a,h)anthracene, benzo(a)pyrene, benzo(a)anthracene and/or indeno(1,2,3-cd)pyrene) correlated with IgA and IgE levels. Conclusions This study showed that coke oven workers with chronic exposure to PAHs may develop immunological alteration. Oxidative stress and lipid peroxidation induced by PAHs may partly explain the alteration in immunological parameters.

Determination of urinary malondialdehyde by isotope dilution LC-MS/MS with automated solid-phase extraction A cautionary note on derivatization optimization

A highly sensitive quantitative LC-MS/MS method was developed for measuring urinary malondialdehyde (MDA). With the use of an isotope internal standard and online solid-phase extraction, urine samples can be directly analyzed within 10 min after 2,4-dinitrophenylhydrazine (DNPH) derivatization. The detection limit was estimated as 0.08 pmol. This method was further applied to assess the optimal addition of DNPH for derivatization and to measure urinary MDA in 80 coke oven emission (COE)-exposed and 67 nonexposed workers. Derivatization optimization revealed that to achieve complete derivatization reaction, an excess of DNPH is required (DNPH/MDA molar ratio: 893-8929) for urine samples that is about 100 times higher than that of MDA standard solutions (molar ratio: 10-80). Meanwhile, the mean urinary concentrations of MDA in COE-exposed workers were significantly higher than those in nonexposed workers (0.23±0.17 vs 0.14±0.05 μmol/mmol creatinine, P<0.005). Urinary MDA concentrations were also significantly associated with the COE (P<0.005) and smoking exposure (P<0.05). Taken together, this method is capable of routine high-throughput analysis and accurate quantification of MDA and would be useful for assessing the whole-body burden of oxidative stress. Our findings, however, raise the issue that derivatization optimization should be performed before it is put into routine biological analysis.

Repeated measurements of urinary methylated/oxidative DNA lesions, acute toxicity, and mutagenicity in coke oven workers

We conducted a repeated-measures cohort study of coke oven workers to evaluate the relationships between the traditional exposure biomarker, urinary 1-hydroxypyrene (1-OHP), and a series of biomarkers, including urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), N7-methylguanine (N7-MeG), acute toxicity, and mutagenicity. A total of eight spot urine samples were collected from each high-exposed (at topside oven area) and low-exposed workers (at side oven area) during the whole working cycle, which consisted of 6 consecutive days of working followed by 2 days off. Our results showed that the high-exposed workers had significantly higher urinary levels of 1-OHP, 8-oxodG, and N7-MeG compared with the low-exposed workers. Acute toxicity and mutagenicity of urine were also found to be markedly increased in the high-exposed workers, as determined by Microtox assay and Ames test, respectively. Multivariate regressions analysis revealed that the urinary 8-oxodG, N7-MeG, or acute toxicity was significantly correlated with 1-OHP concentrations. Overall, the present study showed that exposure to coke oven emissions increased oxidatively damaged DNA products and mutagenicity of urine, and for the very first time, such exposure was also found to increase DNA methylation and urinary acute toxicity. The potential source of methylating agents in coke oven emissions warrants further investigation. Additionally, with repeated measurements, the pattern of time course for urinary 1-OHP was found to be different from those of 8-oxodG and N7-MeG, as well as acute toxicity and mutagenicity. This finding implies that the single measurement that was often conducted in occupational healthy investigations should be used with certain precautions, because single measurement may fail to provide the proper information of interest. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3381–9)

Biomonitoring of polycyclic aromatic hydrocarbons from coke oven emissions and reproductive toxicity in nonsmoking workers.

The objective of the cross-sectional study was to assess whether exposure to polycyclic aromatic hydrocarbons (PAHs) from coke oven emissions contributed to alteration of semen quality and sperm DNA integrity in nonsmoking workers. Nonsmoking coke oven workers from a steel plant in Taiwan served as the exposure groups (topside-oven workers for the high exposure group and side-oven workers for the low exposure group), and administrators and security personnel in the plant served as the control. An exposure assessment was conducted to determine both particulate and gaseous phase of PAH levels and urinary 1-hydroxypyrene (1-OHP) levels. Semen quality was analyzed according to WHO guidelines. DNA fragmentation and bulky DNA adducts were measured to assess sperm DNA integrity. There was no significant difference in sperm concentrations, vitality, and DNA fragmentation between the exposed group and the control. The high exposure group experienced significantly lower percentages of normal morphology as compared with the control (p=0.0001). Bulky DNA adducts were detected in the exposed group that were significant higher than the control (p=0.04). Exposure to PAHs from coke-oven emissions could contribute to increased levels of bulky DNA adducts in sperm.

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.

Immunological findings in a group of coke-oven workers exposed to polycyclic aromatic hydrocarbons.

Learning ObjectivesRecall what past studies have found about adverse effects of polycyclic aromatic hydrocarbons (PAHs).Describe the effects of PAH exposure in coke-oven workers on humoral immunity.Specify the influence on immune function of other factors, particularly smoking. Coke-oven workers are exposed to a high concentration of polycyclic aromatic hydrocarbons, which may change the immunologic responses. In this study, we evaluated humoral immunity by measuring serum IgA, IgE, IgG, and tumor necrosis factor-&agr; in 251 coke-oven workers and 89 rolling steel workers in Taiwan. Mean values of serum IgE and tumor necrosis factor-&agr; levels were 178.8 IU/mL and 8.4 pg/mL in coke-oven workers, respectively, which were significantly higher than in rolling steel workers (102.6 IU/mL and 2.0 pg/mL; P = 0.003 and < 0.001). In contrast, serum IgA levels were significantly lower in coke-oven workers than in rolling steel workers (mean = 264.7 vs 312.0 mg/dL, P < 0.001). Our findings suggest that polycyclic aromatic hydrocarbons exposure may alter the immune responses in coke-oven workers.

1-Hydroxypyrene as a biomarker for assessing the effects of exposure to polycyclic aromatic hydrocarbons on semen quality and sperm DNA integrity

A cross-sectional study was conducted to assess whether urinary 1-hydroxypyrene (1-OHP) could serve as a biomarker to assess the effect of PAHs on cellular and molecular changes of sperm. Urine and semen samples were collected from a total of 65 healthy coke oven workers. Sperm quality parameters (concentration, motility, vitality, and morphology) and semen integrity (DNA fragmentation, 8-oxodGuo, bulky DNA adducts) were analyzed. Sixteen (16) targeted PAHs at the personal breathing zone area were monitored and quantified. Results showed that urinary 1-OHP positively correlated with measured levels of 16 targeted PAHs. Urinary 1-OHP did not significantly correlate with semen quality; however, PAHs with heavy molecular weight, e.g., benzo(g,h,i)perylene and benzo(k)fluoranthene, negatively correlated with morphology and motility of sperms (p = 0.02 and 0.002, p = 0.04 and 0.04, respectively). Urinary 1-OHP positively correlated with the level of 8-oxodGuo and bulky DNA adducts, but not DNA fragmentation. Urinary 1-OHP was a suitable biomarker for an estimate of biologically effective doses of PAH exposure. However, urinary 1-OHP may not be sufficient as a biomarker to assess both cellular and molecular changes of sperm induced by PAHs.

Whole Genome Expression in Peripheral-Blood Samples of Workers Professionally Exposed to Polycyclic Aromatic Hydrocarbons

This study aims to examine global gene expression profiles before and after the work-shift among coke-oven workers (COWs). COWs work six consecutive days and then take two days off. Two blood and urine samples in each worker were collected before starting to work after two days off and end-of-shift in the sixth day of work in 2009. Altered gene expressions (ratio of gene expression levels between end-of-shift and preshift work) were performed by a Human OneArray expression system which probes ~30,000-transcription expression profiling of human genes. Sixteen workers, all men, were enrolled in this study. Median urinary 1-hydroxypyrene (1OHP) levels (μmol/mol creatinine) in end-of-shift work were significantly higher than those in preshift work (2.58 vs 0.29, p = 0.0002). Among the 20,341 genes which passed experimental quality control, 26 gene expression changes, 7 positive and 19 negative, were highly correlated with across-the-shift urinary 1OHP levels (end-of-shift-preshift 1OHP) (p-value <0.001). The high and low exposure groups of across-the-shift urinary 1OHP levels dichotomized in ~2.00 μmol/mol creatinine were able to be distinguished by these 26 genes. Some of them are known to be involved in apoptosis, chromosome stability/DNA repair, cell cycle control/tumor suppressor, cell adhesion, development/spermatogenesis, immune function, and neuronal cell function. These findings in COWs will be an ideal model to study the relationship of PAH exposure with acute changes of gene expressions.

Role of low exposure to metals as male reproductive toxicants.

The objective of the study was to examine the associations between environmentally relevant low metal concentrations and semen quality parameters in men. The concentrations of zinc (Zn), copper (Cu), cadmium (Cd), arsenic (As), selenium (Se), and lead (Pb) in the seminal plasma and urine were measured from 196 male human subjects in Taiwan. Urinary Cd concentrations were negatively associated with sperm viability (p = 0.006). Seminal plasma Cu concentrations of the normal group (≥ 15 × 106/ml) were significantly lower than those of the abnormal group (p = 0.023). However, the linear regression analysis showed a weak association between Cu concentration and sperm concentration, along with other semen parameters. No significant relationship between other metals (As, Pb, Zn, and Se) and semen quality was observed.

Reduction of cooking oil fume exposure following an engineering intervention in Chinese restaurants

Background A new engineering intervention measure, an embracing air curtain device (EACD), was used to increase the capture efficiency of cooker hoods and reduce cooking oil fume (COF) exposure in Chinese restaurants. Methods An EACD was installed in six Chinese restaurants where the cooks complained of COF exposure. Before- and after-installation measurements were taken to compare changes in particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) in kitchen air, and changes in levels of urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) and malondialdehyde (MDA). The association between PM and PAHs in air and 8-OHdG and MDA in urine was evaluated by linear mixed-effects regression analysis. Results Results showed that geometric mean kitchen air levels of PM10, PM2.5, PM1.0 and total particulate PAHs were significantly reduced after the EACDs were introduced. Urinary levels of 8-OHdG and MDA in cooks were also significantly lower after EACD instalment. PM2.5, PM1.0 and benzo(a)pyrene (BaP) levels were positively associated with urinary 8-OHdG levels after adjusting for key personal covariates. Urinary MDA levels in cooks were also positively associated with BaP levels after adjusting for key personal covariates. Conclusion This study demonstrates that the EACD is effective for reducing COF and oxidative stress levels in cooks working in Chinese kitchens.