Measurement of urinary arsenic profiles and DNA hypomethylation in a case-control study of urothelial carcinoma.

Environmental exposure to arsenic may be involved in the disturbance of DNA hypomethylation. The aim of this study is the first to explore the effect of interactions of urinary total arsenic levels, arsenic methylation capacity, 8-hydroxy-2'-deoxyguanosine (8-OHdG), plasma folate, and global 5-methyl-2'-deoxycytidine (5-MedC) levels on the risk of urothelial carcinoma (UC). A hospital-based case-control study was constructed. The research involved the histological recruitment and pathological verification of 178 UC patients and 356 age-/sex-matched controls without prior history of cancer. Arsenic species were determined by high-performance liquid chromatography (HPLC)-hydride generation and atomic absorption. 5-MedC levels were detected by HPLC and triple-quadrupole mass spectrometry (MS). 8-OHdG was processed by an online solid-phase extraction LC-MS/MS. Plasma folate levels were measured using the chemiluminescent technology. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by multiple logistic regression analysis. Results indicate that the high levels of total urinary arsenic, inorganic arsenic percentage, and 8-OHdG and the low levels of DMA % and plasma folate were independent factors of UC. In addition, global 5-MedC levels in the first quartile versus fifth quartile significantly increased the twofold OR of UC after potential factors were adjusted (95% CI:1.10-4.03). The interaction of 5-MedC level and high total arsenic level, insufficient arsenic capacity, high 8-OHdG, and low folate levels was insignificant. Results of stepwise logistic regression analysis indicate that high total urinary arsenic levels (Q3 versus Q1), low plasma folate level, and low global 5-MedC (Q4 versus Q5) significantly increased the ORs of UC. The above results suggest that high total arsenic, low plasma folate, and 5-MedC levels affect the ORs of UC independently.

Identification of osteopontin as a biomarker of human exposure to fine particulate matter.

Ambient particulate matter (PM) exposure is associated with pulmonary and cardiovascular diseases; however, there is scant research linking data on animal and human cells. The objective of this study was to investigate these associations. Vascular remodeling plays a crucial role in both pulmonary and cardiovascular diseases. Therefore, we conducted a transcriptomic analysis using vascular smooth muscle cells (VSMCs) to identify potential regulators or markers of PM exposure. We demonstrated that fine and coarse PM increased VSMC proliferation in mice. We conducted a genome-wide cDNA microarray analysis, followed by a pathway analysis of VSMCs treated with coarse PM for durations of 24, 48, and 72 h. Sixteen genes were discovered to be time-dependently upregulated and involved in VSMC proliferation. Osteopontin (OPN) is indicated as one of the regulators of these upregulated genes. Both fine and coarse PM from industrial and urban areas significantly increased OPN expression in VSMCs and macrophages. Moreover, oropharyngeal instillation of fine and coarse PM for 8 weeks increased the VSMCs in the pulmonary arteries of mice. OPN level was consistently increased in the lung tissues, bronchoalveolar lavage fluid, and serum of mice. Moreover, we analyzed the plasma OPN levels of 72 healthy participants recruited from the studied metropolitan area. Each participant wore a personal PM2.5 sampler to assess their PM2.5 exposure over a 24 h period. Our results indicate that personal exposure to fine PM is positively correlated with plasma OPN level in young adults. The data obtained in this study suggest that exposure to fine and coarse PM may cause pulmonary vascular lesions in humans and that OPN level may be a biomarker of PM exposure in humans.

Levels and temporal variations of urinary lead, cadmium, cobalt, and copper exposure in the general population of Taiwan.

Toxic metal contamination in food products and the environment is a public health concern. Therefore, understanding human exposure to cadmium (Cd), lead (Pb), cobalt (Co), and copper (Cu) levels in the general population of Taiwan is necessary and urgent. We aimed to establish the human biomonitoring data of urine toxic metals, exposure profile changes, and factors associated with metal levels in the general population of Taiwan. We randomly selected 1601 participants older than 7 years of age (36.9 ± 18.7 years (7-84 years)) from the Nutrition and Health Survey in Taiwan (NAHSIT) conducted during 1993-1996 (93-96) and 2005-2008 (05-08) periods and measured the levels of four metals in the participants' urine samples using inductively coupled plasma-mass spectrometry. The median (range) levels of urinary Cd, Pb, Co, and Cu in participants from the NAHSIT 93-96 (N = 821)/05-08 (N = 780) were 0.60 (ND-13.90)/0.72 (ND-7.44), 2.28 (ND-63.60)/1.09 (0.04-48.88), 0.91 (0.08-17.30)/1.05 (0.05-22.43), and 16.87 (2.62-158.28)/13.66 (1.67-189.70) µg/L, respectively. We found that the urinary median levels of Pb and Cu in our participants were significantly lower in the NAHSIT 05-08 (Pb 1.09 µg/L, Cu 13.66 µg/L) than in the NAHSIT 93-96 (Pb 2.28 µg/L, Cu 16.87 µg/L; P < 0.01), whereas those of Cd and Co were significantly higher in the NAHSIT 05-08 (Cd 0.72 µg/L, Co 1.05 µg/L; P < 0.01). Youths had higher exposure levels of Pb, Co, and Cu than adults. Participants with alcohol consumption, betel quid chewing, or cigarette smoking had significantly higher median levels of urinary Pb or Cu (P < 0.01) than those without. Principal components and cluster analysis revealed that sex had different exposure profiles of metals. We concluded that levels of urinary Cd, Pb, Co, and Cu exposure in the general Taiwanese varied by age, sex, and lifestyles.

Clustering of malignant pleural mesothelioma in asbestos factories: a subgroup analysis in a 29-year follow-up study to identify high-risk industries in Taiwan.

OBJECTIVE: Exposure to asbestos is the major cause for malignant pleural mesothelioma (MPM), but the causal link of individual cases is difficult to establish for lack of exposure information and long disease latency. METHODS: We established a retrospective cohort of workers employed in asbestos industries during the period of 1950-1989 and the occurrence of MPM during the period of 1980-2009 was examined with the Taiwan Cancer Registry. Estimated rate ratios (eRRs) were computed for each factory where any case of MPM was diagnosed by assuming Poisson distribution with a minimal latency of 20 years. RESULTS: A total of 18 MPM (17 males, 1 female) in eight factories were found. The incidence rate of MPM for the eight factories was 18.0 per million, ranging from 6.2 per million (military factory) to 268.2 per million (asbestos cement). We observed significantly increased risks for MPM in asbestos cement, thermal insulation and shipbuilding industries, with eRR (genders combined) of 113.6, 87.5 and 15.8, respectively. The sensitivity analyses considering latency showed similar findings in latency ≥30 years, and the shipbuilding industry presented a significant eRR given a latency ≥40 years. The gender-specific eRR showed similar results in men, but high eRR of 729.6 was observed in an asbestos cement factory where a female MPM was diagnosed. CONCLUSIONS: This nationwide study in Taiwan comprehensively shows that different asbestos manufacturing processes, including asbestos cement, thermal insulation and shipbuilding industries, were at significantly increased risks for MPM. We recommend to establish a medical screening programme for workers previously exposed to asbestos to identify MPM and other asbestos-related diseases at an earlier stage.

The impact of occupational psychological hazards and metabolic syndrome on the 8-year risk of cardiovascular diseases-A longitudinal study.

There was little information concerning the combined effect of occupational psychosocial hazards such as long working hours, high job stress, and high fatigue on the risk of cardiovascular and cerebrovascular diseases (CVD). The aim of this study was to investigate the interaction among occupational psychosocial hazards and the impact of metabolic syndrome (MetS) on the risk of CVD among bus drivers. The Taiwan Bus Driver Cohort Study involving 1014 professional drivers was established in 2005 and comprehensively studied. The interactions among occupational psychosocial hazards and the impact of MetS on the risk of CVD were measured. A working pattern questionnaire, job stress questionnaires, the Swedish occupational fatigue inventory, the stress satisfaction offset score, biochemical measurements, and physical examinations were used to assess psychosocial hazards and the presence of metabolic syndrome. There were 707 eligible bus drivers with a mean age of 43.5years old. During the 8-years of follow-up, 77 drivers were diagnosed with CVD. Long working hours, high job stress, and high fatigue were associated with an increased risk of cardiovascular disease incidence in the multivariate analysis. There were synergistic effects among long working hours, high job stress, and high fatigue only in drivers with MetS. A combination of long working hours, high job stress, and high fatigue increased the risk of developing CVD in bus drivers with MetS.

Feasibility of using urinary N7-(2-carbamoyl-2-hydroxyethyl) Guanine as a biomarker for acrylamide exposed workers.

Acrylamide (AA), a probable human carcinogen, is a widely-used industrial chemical but is also present in tobacco smoke and carbohydrate-rich foods processed at high temperatures. AA is metabolized to glycidamide (GA) to cause the formation of DNA adducts. N7-(2-carbamoyl-2-hydroxyethyl) guanine (N7-GAG), the most abundant DNA adduct induced by GA, was recently detected in urine of smokers and non-smokers. In this study, we assessed the variability of AA exposure and biomarkers of AA exposure in urine samples repeatedly collected from AA-exposed workers and explored the half-life of N7-GAG. A total of 8 AA-exposed workers and 36 non-exposed workers were recruited. Pre-shift and post-shift urine samples were collected from the exposed group in parallel with personal sampling for eight consecutive days and from the control group on day 1 of the study. Urinary N7-GAG and the mercapturic acids of AA and GA, namely N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) and N-(R,S)-acetyl-S-(1-carbamoyl-2-hydroxyethyl)-L-cysteine (GAMA) were analyzed using on-line solid phase extraction-liquid chromatography-electrospray ionization/tandem mass spectrometry methods. We found that N7-GAG levels in urine were significantly higher in exposed workers than in controls and that N7-GAG level correlated positively with AAMA and GAMA levels. Results from this study showed that AAMA and GAMA possibly remain the more preferred biomarkers of AA exposure and that N7-GAG levels could be elevated by occupational exposures to AA and serve as a biomarker of AA-induced genotoxicity for epidemiological studies.

Exposure to fine particulate matter causes oxidative and methylated DNA damage in young adults: A longitudinal study.

An increased understanding is needed of the physiological effects and plausible biological mechanisms that link PM2.5 (particulate matter with an aerodynamic diameter below 2.5µm) exposure to mortality and morbidities such as atherosclerosis and respiratory disease. PM2.5 causes carcinogenic health effects. Biomonitoring in humans has suggested that 8-oxo-7, 8-dihydro-2-deoxyguanosine (8-oxodG) and N7-methylguanine (N7-MeG) are correlated with oxidative and methylated DNA damage. Thus, it is meaningful to explore the mechanisms of mutagenesis and carcinogenesis associated with oxidative and methylated DNA damage by simultaneously measuring these two markers. We recruited 72 participants from 2 areas (residential and commercial as well as residential and industrial) in the greater Taipei metropolitan area at baseline. Personal samplers were used to collect 24-hour PM2.5-integrated samples. All participants completed an interview, and blood and urine samples were collected the next morning. All collection procedures were repeated twice after a two-month follow-up period. Urinary 8-oxodG and N7-MeG were assayed as biomarkers of oxidative and methylated DNA damage, respectively. Plasma superoxide dismutase (SOD) and glutathione peroxidase-1 (GPX-1) were measured as biomarkers of antioxidants. Urinary 1-hydroxypyrene (1-OHP) was used as a biomarker of exposure to polycyclic aromatic hydrocarbons (PAHs). The mean PM2.5 level was 37.3µg/m3 at baseline. PM2.5 concentrations were higher during winter than during spring and summer. After adjusting for confounds through a generalized estimating equation (GEE) analysis, N7-MeG was significantly increased by 8.1% (ß=0.034, 95% CIs=0.001-0.068) per 10µg/m3 increment in PM2.5. 8-oxodG levels were positively correlated with N7-MeG according to both cross-sectional and longitudinal analyses, and 1-OHP was significantly associated with increasing 8-oxodG and N7-MeG concentrations. Exposure to PM2.5 increases methylated DNA damage. The mean level of urinary N7-MeG was 1000-fold higher than that of 8-oxodG.

Relationships among DNA hypomethylation, Cd, and Pb exposure and risk of cigarette smoking-related urothelial carcinoma.

Cigarette smoking and environmental exposure to heavy metals are important global health issues, especially for urothelial carcinoma (UC). However, the effects of cadmium and lead exposure, as well as the levels of DNA hypomethylation, on UC risk are limited. We evaluated the possible exposure sources of Cd and Pb and the relationship among DNA hypomethylation, urinary Cd and Pb levels, and UC risk. We recruited 209 patients with UC and 417 control patients for a hospital-based case-control study between June 2011 and August 2014. We collected environmental exposure-related information with questionnaires. Blood and urine samples were analyzed to measure the Cd and Pb exposure and 5-methyl-2'-deoxycytidine levels as a proxy for DNA methylation. Multivariate logistic regression and 95% confidence intervals were applied to estimate the risk for UC. Study participants with high Cd and Pb exposure in blood or urine had significantly increased risk of UC, especially among the smokers. After adjusting for age and gender, the possible connections of individual cumulative cigarette smoking or herb medicine exposure with the increased levels of Cd and Pb were observed in the controls. Participants with 8.66%-12.39% of DNA hypomethylation had significantly increased risk of UC compared with those with ≥12.39% of DNA hypomethylation. Environmental factors including cigarette smoking and herb medicine may contribute to the internal dose of heavy metals levels. Repeat measurements of heavy metals with different study design, detailed dietary information, and types of herb medicine should be recommended for exploring UC carcinogenesis in future studies.

Effect of CYP3A4 genetic polymorphisms on the genotoxicity of 4,4'-methylene-bis(2-chloroaniline)-exposed workers.

OBJECTIVES: We investigated the relationship between 4,4'-methylene-bis(2-chloroaniline) (MBOCA) exposure and micronucleus (MN) frequency, and how this association was affected by genetic polymorphism of the cytochrome P450 enzyme (CYP3A4). METHODS: We divided the study population into an exposed group (n=44 with total urine MBOCA ≥20 µg/g creatinine) and a control group (n=47 with total urine MBOCA <20 µg/g creatinine). Lymphocyte MN frequency (MNF) and micronucleated cell (MNC) frequency were measured by the cytokinesis-block MN assay method. MNF reported as the number of micronuclei in binucleated cells per 1000 cells, and MNC reported as the number of binucleated cells with the presence of MN per 1000 cells. CYP3A4 alleles were measured by PCR-based restriction fragment length polymorphism (PCR-RFLP). RESULTS: The mean MNF (6.11 vs 4.46 MN/1000 cells, p<0.001) and MNC (5.75 vs 4.15 MN/1000 cells, p<0.001) in the exposed workers was significantly higher than that in the controls. The CYP3A4 polymorphism A/A+A/G influenced the difference in the mean MNF (5.97 vs 4.38 MN/1000 cells, p<0.001) and MNC (5.60 vs 4.15 MN/1000 cells, p<0.001) between the MBOCA-exposed and control groups. After adjusting risk factors, the MNF level in the MBOCA-exposed workers was 0.520 MN cells/1000 cells (p<0.001) higher than the control group among the CYP3A4 A/A+A/G genotype. Similarly, the MNC level in the MBOCA-exposed workers was 0.593 MN/1000 cells (p<0.001) higher than the control group among the CYP3A4 A/A+A/G genotype. However, the difference in adjusted MNF and MNC between the exposed and control groups was not significant for the CYP3A4 polymorphism with the G/G genotype. CONCLUSIONS: We recommend that lymphocytes MNF and MNC are good indicators to evaluate MBOCA genotoxicity. Individuals with the CYP3A4 polymorphism A/A and A/G genotypes appear to be more susceptible to MBOCA genotoxicity.

The relationship between plasma and urinary 8-hydroxy-2-deoxyguanosine biomarkers measured by liquid chromatography tandem mass spectrometry.

Although 8-hydroxy-2-deoxyguanosine (8-OHdG) is a widely used promising biomarker of DNA damage, there are concerns about which tissues or body fluids should be sampled. The objective of this study is to evaluate the correlation of DNA oxidative damage biomarkers, 8-OHdG, between blood and urine and risk factors associated with 8OHdG. The study population was recruited from a baseline survey of a worksite lifestyle study including 92 office workers aged 23 to 60 years. A self-administered questionnaire was used to collect information on personal characteristics. The plasma and urinary 8-OHdG was measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). In linear regression, a positive relation was found (p < 0.01) between the log-transformed plasma and urinary 8-OHdG levels adjusted for gender, age, BMI, and smoking status. Our findings showed that age, gender and smoking were significantly associated with plasma 8-OHdG, but not with urinary 8-OHdG. Our results suggest that there is a positive relation between the biomarkers of plasma (steady state DNA damage) and urinary 8-OHdG (total DNA damage). However, the plasma 8-OHdG is more sensitive than urinary 8-OHdG to detect increased oxidative damages induced by risk factors.

Association between levels of urinary heavy metals and increased risk of urothelial carcinoma.

OBJECTIVES: To evaluate possible sources of exposure to heavy metals in the general population, and to determine the association between urinary heavy metals and urothelial carcinoma risk. METHODS: We recruited 205 patients with urothelial carcinoma and 406 control participants for a case-control study between June 2011 and December 2013. The control participants were frequency-matched with cases according to sex and age. We measured the urinary levels of arsenic, cadmium, chromium, nickel and lead by using inductively coupled plasma mass spectrometry. We collected environmental exposure-related information through questionnaires. Multivariate logistic regression and 95% confidence intervals were applied to estimate the urothelial carcinoma risk and potential effects of urothelial carcinoma-related risk factors on the levels of urinary heavy metals. RESULTS: Patients with urothelial carcinoma showed higher urinary levels of arsenic, cadmium, chromium, nickel and lead than the controls. After considering other potential risk factors, a significantly increased risk for urothelial carcinoma was observed in patients with increased urinary levels of cadmium, chromium, nickel and lead. Smokers showed a high urinary cadmium level. In addition to cadmium, a high urinary lead level was associated with cumulative cigarette smoking and herbal medicine use. CONCLUSION: Environmental factors might contribute to higher urinary levels of heavy metals and ultimately result in urothelial carcinoma carcinogenesis. These findings can promote proper environmental surveillance of exposure to heavy metals in the general population.

Association between urinary lead and bone health in a general population from Taiwan.

Lead accumulates in adult bones for many decades; previous studies have shown lead's detrimental effects on osteoblast and osteoclast activity in association with bone remodeling. Osteoporosis is a disease of the bones resulting in low bone mass that induces fragile bones and hence susceptibility of fracture. We estimated the association between urinary lead (U-Pb) levels and bone health in adults participating in the third Nutrition and Health Survey in Taiwan (NAHSIT) from 2005 to 2008. A total of 398 participants were divided into normal (T-score>-1), osteopenic (T-score between -1 and -2.5), or osteoporotic (T-score<-2.5) groups according to the results of bone mineral density (BMD) measurements. Heavy metals were measured in urine specimens using inductively coupled plasma-mass spectrometry. In the multivariable logistic regression analysis, age (OR=1.08; 95% CI=1.05-1.10), former smokers (OR=2.95; 95% CI=1.22-7.11) and higher U-Pb levels than upper tertile (OR=2.30; 95% CI=1.19-4.48) were associated with osteopenia/osteoporosis. Furthermore, age (OR=1.06; 95% CI=1.02-1.10) and higher U-Pb levels (OR=2.81; 95% CI=1.13-6.97) were significantly associated with osteopenia and osteoporosis in women. These results suggest that adults, particularly in women, with higher U-Pb levels may have increased odds of osteopenia and osteoporosis.

Cancer Attributable to Asbestos Exposure in Shipbreaking Workers: A Matched-Cohort Study.

PURPOSE: Long-term follow-up studies of asbestos-related cancer in shipbreaking workers are lacking. This study examines the relationship between cancer incidence and asbestos exposure among former Taiwan shipbreaking workers. METHODS: A total of 4,427 shipbreaking workers and 22,135 population-based matched controls were successfully followed in this study. The study cohort was linked to the Taiwan Cancer Registry for new cancer cases. The adjusted hazard ratio (aHR) for cancer was calculated for the shipbreaking workers with Total Exposure Potential Scores (TEP) for asbestos. RESULTS: Follow-up generated 109,932 person-years, with 940 deaths and 436 cancer cases, among 4,427 shipbreaking workers from 1985 to 2008. The high asbestos exposure group also had a statistically significant increase in the risk of overall cancer (aHR= 1.71; 95% CI: 1.42-2.05), esophagus cancer (aHR= 2.31; 95% CI: 1.00-5.41), liver and intrahepatic bile duct cancer (aHR= 1.60; 95% CI: 1.08-2.36), and trachea, bronchus, and lung cancer (aHR= 3.08; 95% CI: 1.80-5.25). Mesothelioma cases were found in the high asbestos exposure group. Moreover, overall cancer, esophagus cancer, and trachea, bronchus, and lung cancer were seen in a dose-dependent relationship with asbestos exposure. CONCLUSIONS: This study presented the elevated trend of asbestos exposure with cancer incidence for overall cancer, esophagus cancer, and trachea, bronchus, and lung cancer among shipbreaking workers. Those workers previously exposed to asbestos should receive persistent monitoring in order to early detect adverse health outcomes.

Nickel may contribute to EGFR mutation and synergistically promotes tumor invasion in EGFR-mutated lung cancer via nickel-induced microRNA-21 expression.

We recently reported that nickel accumulation in lung tissues may be associated with an increased in p53 mutation risk via reduced DNA repair activity. Here, we hypothesized that nickel accumulation in lung tissues could contribute to EGFR mutations in never-smokers with lung cancer. We enrolled 76 never-smoking patients to evaluate nickel level in adjacent normal lung tissues by ICP-MS. The prevalence of EGFR mutations was significantly higher in the high-nickel subgroup than in the low-nickel subgroup. Intriguingly, the OR for the occurrence of EGFR mutations in female, adenocarcinoma, and female adenocarcinoma patients was higher than that of all patients. Mechanistically, SPRY2 and RECK expressions were decreased by nickel-induced miR-21 via activation of the EGFR/NF-κB signaling pathway, which promoted invasiveness in lung cancer cells, and particularly in the cells with EGFR L858R expression vector transfection. The patients' nickel levels were associated with miR-21 expression levels. Kaplan-Meier analysis revealed poorer overall survival (OS) and shorter relapse free survival (RFS) in the high-nickel subgroup than in low-nickel subgroup. The high-nickel/high-miR-21 subgroup had shorter OS and RFS periods when compared to the low-nickel/low-miR-21 subgroup. Our findings support previous epidemiological studies indicating that nickel exposure may not only contribute to cancer incidence but also promote tumor invasion in lung cancer.

The impact of obstructive sleep apnea on high-sensitivity C-reactive protein in subjects with or without metabolic syndrome.

BACKGROUND: It is unclear whether obstructive sleep apnea (OSA) is independently associated with increased levels of the acute-phase reactant C-reactive protein (CRP). The purpose of this study was to evaluate the relationship between OSA and high-sensitivity CRP (hs-CRP) levels according to the presence or absence of metabolic syndrome (MetS). METHODS: This study recruited 245 male bus drivers from one transportation company in Taiwan. Each participant was evaluated by a polysomnography (PSG) test, blood lipids examination, and hs-CRP. Severity of OSA was categorized according to the apnea-hypopnea index (AHI). RESULTS: Subjects were categorized into severe OSA group (n = 44; 17.9 %), moderate and mild OSA group (n = 117; 47.8 %), and non-OSA group (n = 84; 34.3 %). AHI had a significant association with hs-CRP (ß = 0.125, p = 0.009) adjusting for age, smoking, drinking, and MetS status. Hs-CRP was elevated with severe OSA (ß = 0.533, p = 0.005) even adjusting for BMI and MetS. Moreover, there was an independent effect for adjusted odds ratios (AORs) between the stratification of the severity for OSA and MetS. CONCLUSION: Elevated hs-CRP level is associated with severe OSA, independent of known confounders. The effect of OSA in CRP is independent of MetS was identified.

Potential Association of Urinary N7-(2-Carbamoyl-2-hydroxyethyl) Guanine with Dietary Acrylamide Intake of Smokers and Nonsmokers.

Acrylamide (AA), a rodent carcinogen, is widely used in industry and present in cigarette smoke as well as in foods processed at high temperatures. The metabolic activation of AA to glycidamide (GA) could be critical for AA carcinogenicity since GA causes DNA adduct formation in vivo. N7-(2-carbamoyl-2-hydroxyethyl) guanine (N7-GAG), the most abundant DNA adduct of AA, is subjected to spontaneous and enzymatic depurination and excreted through urine. Urinary N7-GAG analysis can confirm AA genotoxicity and identify active species of AA metabolites in humans, thereby serving as a risk-associated biomarker for molecular epidemiology studies. This study aimed to develop an isotope-dilution solid-phase extraction liquid chromatography tandem mass spectrometry method to comparatively analyze urinary N7-GAG levels in nonsmokers and smokers. Urinary N-acetyl-S-(propionamide)-cysteine (AAMA), a metabolite of AA, was also analyzed as a biomarker for current AA exposure. Urinary N7-GAG was quantified by monitoring m/z 239 → 152 for N7-GAG and m/z 242 → 152 for (13)C3-labeled N7-GAG under positive electron spray ionization and multiple reaction mode. The median urinary N7-GAG level was 0.93 µg/g creatinine in nonsmokers (n = 33) and 1.41 µg/g creatinine in smokers (n = 30). Multiple linear regression analysis of data revealed that N7-GAG levels were only significantly associated with AAMA levels. These results demonstrate that urinary N7-GAG of nonsmokers and smokers is significantly associated with a very low level of dietary AA intake, assessed by analyzing urinary AAMA.

Cancer incidence of Taiwanese shipbreaking workers who have been potentially exposed to asbestos.

BACKGROUND: Shipbreaking remains one of the most dangerous jobs worldwide. Shipbreaking workers are exposed to many hazardous chemicals, especially asbestos. Unfortunately, long-term follow-up studies of cancer incidence patterns in shipbreaking workers are lacking. This study examines whether there is an increased risk of cancer among male shipbreaking workers over a 24-year follow-up period. METHODS: 4155 male shipbreaking worker's information was retrospectively collected from Kaohsiung's Shipbreaking Workers Union database from 1985. The study cohort was linked to the Taiwan Cancer Registry from 1985 to 2008 for new cancer cases. The expected number of cancers for shipbreaking workers was calculated by using the age (5-year intervals) and calendar time-specific annual rates of cancer incidence with reference to the general population of Taiwan from 1985 to 2008. Standardized incidence ratios (SIRs) were calculated as relative risk estimates. The hazard ratio (HR) for cancer was calculated for the shipbreaking workers with Total Exposure Potential Scores for asbestos. RESULTS: After consideration of a 5-year latency period, an elevated incidence of overall cancer (N=368; SIR=1.13 (1.01-1.25)), oral cavity cancer (N=83; SIR=1.99 (1.58-2.46)), and trachea, bronchus, and lung cancers (N=53; SIR=1.36 (1.02-1.78)) was found among male shipbreaking employees. Moreover, mesothelioma cases were found in those who had the occupation of flame cutter. The high asbestos exposure group was associated with an increased SIR of developing overall cancer and oral cancer, whether we considered a 5-year or 10-year latency period. CONCLUSION: Asbestos-related diseases, including lung cancer and mesothelioma, were seen in excess in these shipbreaking workers and some cases appeared to have a dose-dependent relationship. Preventative measures among male shipbreaking workers should be researched further.

Nickel accumulation in lung tissues is associated with increased risk of p53 mutation in lung cancer patients.

Occupational exposure to nickel compounds has been associated with lung cancer. The correlation between high nickel levels and increased risk of lung cancer has been previously reported in a case-control study. This study assessed whether nickel exposure increased the occurrence of p53 mutations due to DNA repair inhibition by nickel. A total of 189 lung cancer patients were enrolled to determine nickel levels in tumor-adjacent normal lung tissues and p53 mutation status in lung tumors through atomic absorption spectrometry and direct sequencing, respectively. Nickel levels in p53 mutant patients were significantly higher than those in p53 wild-type patients. When patients were divided into high- and low-nickel subgroups by median nickel level, the high-nickel subgroup of patients had an odds ratio (OR) of 3.25 for p53 mutation risk relative to the low-nickel subgroup patients. The OR for p53 mutation risk of lifetime non-smokers, particularly females, in the high-nickel subgroup was greater than that in the low-nickel subgroup. To determine whether nickel affected DNA repair capacity, we conducted the host cell reactivation assay in A549 and H1975 lung cancer cells and showed that the DNA repair activity was reduced by nickel chloride in a dose-dependent manner. This was associated with elevated production of hydrogen peroxide-induced 8-oxo-deoxyguanosine. Therefore, increased risk of p53 mutation due to defective DNA repair caused by high nickel levels in lung tissues may be one mechanism by which nickel exposure contributes to lung cancer development, especially in lifetime female non-smokers.

Crucial role of Toll-like receptors in the zinc/nickel-induced inflammatory response in vascular endothelial cells.

Our previous studies indicated that zinc induced inflammatory response in both vascular endothelial cells and promonocytes. Here, we asked if other metals could cause the similar effect on vascular endothelial cells and tried to determine its underlying mechanism. Following screening of fifteen metals, zinc and nickel were identified with a marked proinflammatory effect, as determined by ICAM-1 and IL-8 induction, on human umbilical vein endothelial cells (HUVECs). Inhibiting protein expression of myeloid differentiation primary response protein-88 (MyD88), a Toll-like receptor (TLR) adaptor acting as a TLR-signaling transducer, significantly attenuated the zinc/nickel-induced inflammatory response, suggesting the critical roles of TLRs in the inflammatory response. Blockage of TLR-4 signaling by CLI-095, a TLR-4 inhibitor, completely inhibited the nickel-induced ICAM-1 and IL-8 expression and NFκB activation. The same CLI-095 treatment significantly blocked the zinc-induced IL-8 expression, however with no significant effect on the ICAM-1 expression and a minor inhibitory effect on the NFκB activation. The finding demonstrated the differential role of TLR-4 in regulation of the zinc/nickel-induced inflammatory response, where TLR-4 played a dominant role in NFκB activation by nickel, but not by zinc. Moreover, inhibition of NFκB by adenovirus-mediated IκBα expression and Bay 11-7025, an inhibitor of cytokine-induced IκB-α phosphorylation, significantly attenuated the zinc/nickel-induced inflammatory responses, indicating the critical of NFκB in the process. The study demonstrates the crucial role of TLRs in the zinc/nickel-induced inflammatory response in vascular endothelial cells and herein deciphers a potential important difference in NFκB activation via TLRs. The study provides a molecular basis for linkage between zinc/nickel exposure and pathogenesis of the metal-related inflammatory vascular disease.

Mortality among shipbreaking workers in Taiwan--a retrospective cohort study from 1985 to 2008.

BACKGROUND: Shipbreaking workers are typically exposed to a wide range of hazardous chemicals. However, long-term follow-up studies of their mortality patterns are lacking. This study examined mortality among shipbreaking workers over a 24-year follow-up period. METHODS: A total of 4,962 shipbreaking workers were recruited from the database of the Kaohsiung Shipbreaking Workers Union. The data were then linked to the Taiwan National Death Registry from 1985 to 2008. The mortality ratios-standardized for age and calendar years-(SMRs) for various causes of deaths were calculated with reference to the general population of Taiwan. RESULTS: Among men workers, a statistically significant increased SMR was observed for all causes (SMR = 1.28), all cancers (SMR = 1.26; particularly noteworthy for lesions of oral and nasopharyngeal: SMR 2.03, liver: SMR 4.63, and lung: SMR 1.36), cirrhosis of the liver (SMR = 1.32), and accidents (SMR = 1.91). A statistically significant increase in mortality was observed for respiratory system cancer (SMR = 1.87) and lung cancer (SMR = 1.91) among workers with a longer duration of employment (≥7 years). The result also showed that among shipbreaking workers who were still alive, two people had mesothelioma and 10 people have asbestosis. CONCLUSIONS: Those employed in shipbreaking industries experienced an increase in mortality from all causes. The increased SMR for lung cancer was probably related to asbestos, metals, and welding fume exposure.