Wan-Fen Li

Association between phthalate exposure and glutathione S-transferase M1 polymorphism in adenomyosis, leiomyoma and endometriosis

BACKGROUND Phthalates are known to have estrogenic effects in cell models and experimental animals. However, the evidence regarding the effects of phthalates on human reproduction is still limited. We conducted a case-control study to determine whether estrogen-dependent diseases are associated with phthalate exposure and how the glutathione S-transferase M1 (GSTM1; a major detoxification enzyme) genotype modulates the risk. METHODS We recruited subjects who underwent laparotomy and had pathologic confirmation of endometriosis (EN) (n = 28), adenomyosis (AD) (n = 16) and leiomyoma (LEI) (n = 36) from the Department of Obstetrics and Gynecology at a medical center in Taiwan between 2005 and 2007. Controls (n = 29) were patients without any of the three aforementioned gynecologic conditions. Urine samples were collected before surgery and analyzed for seven phthalate metabolites using liquid chromatography-tandem mass spectrometry. Peripheral lymphocytes were used for GSTM1 genotype determination. RESULTS Patients with LEIs had significantly higher levels of total urinary mono-ethylhexyl phthalate (SigmaMEHP; 52.1 versus 18.9 microg/g creatinine, P < 0.05) than the controls, whereas patients with EN had an increased level of urinary mono-n-butyl phthalate (94.1 versus 58.0 microg/g creatinine, P < 0.05). Subjects with GSTM1 null genotype had significantly increased odds for AD relative to those with GSTM1 wild genotype [odds ratio (OR) = 5.30; 95% CI, 1.22-23.1], even after adjustment for age and phthalate exposure. Subjects who carried the GSTM1 null genotype and had a high urinary level of SigmaMEHP showed a significantly increased risk for AD (OR = 10.4; 95% CI, 1.26-85.0) and LEIs (OR = 5.93; 95% CI, 1.10-31.9) after adjustment for age, compared with those with GSTM1 wild-type and low urinary level of SigmaMEHP. CONCLUSIONS These results suggest that both GSTM1 null and phthalate exposure are associated with AD and LEI. Larger studies are warranted to investigate potential interaction between GSTM1 null and phthalate exposure in the etiology of estrogen-dependent gynecologic conditions.

Six-month follow-up study of health markers of nanomaterials among workers handling engineered nanomaterials

Abstract The aim of this study was to identify the health hazards and possible exposure surveillance markers of workers exposed to nanoparticles during manufacturing and application in comparison to a group of unexposed workers. For this longitudinal study, we recruited 158 nanomaterial-handling workers and 104 non-exposed workers from 14 manufacturing plants in Taiwan (baseline). Among them, 124 nanomaterial-handling workers and 77 unexposed workers were monitored 6 months later. We investigated pulmonary and cardiovascular disease markers, inflammation and oxidative stress markers, antioxidant enzymes and genotoxicity markers. Antioxidant enzymes (superoxide dismutase, glutathione peroxidase) and cardiovascular markers (vascular cell adhesion molecule, paraoxonase) were significantly associated with nanomaterial-handling during the 6-month follow-up period. In addition, the small airway damage marker (Clara cell protein 16) and lung function test parameters were also significantly associated with handling nanomaterials. The study markers and lung function tests are possible markers that could be useful for surveillance of nanomaterial-handling workers.

The association between total urinary arsenic concentration and renal dysfunction in a community-based population from central Taiwan

Arsenic (As) is an important environmental toxicant that can cause cancer and cardiovascular disease, but the relationship between As exposure and renal dysfunction is not clear. The aim of this study is to examine the association between As exposure and renal dysfunction in a community-based population in central Taiwan. One thousand and forty-three subjects were recruited between 2002 and 2005. The risk for type 2 diabetes was increased by 2-fold (p<0.05) in subjects with total urinary As (U-As)>75 μg g(-1) creatinine as compared with subjects whose U-As was ≤ 35 μg g(-1) creatinine after the adjustment for potential confounders. The adjusted odds ratio for an abnormal β2 microglobulin (B2MG>0.154 mg L(-1)) was significantly higher in subjects with U-As>35 μg g(-1) creatinine as compared with the reference group adjusted for age, sex, living area, cigarette smoking, diabetes, and hypertension. The risk for abnormal B2MG and estimated glomerular filtration rate (eGFR<90 mL min(-1)(1.73 m(2))(-1)) was both increased around 2-fold (p<0.05) in subjects with U-As>75 μg g(-1) creatinine as compared with those with U-As ≤ 35 μg g(-1) creatinine adjusted for all the risk factors plus lead (Pb), cadmium and nickel. The prevalence of abnormal B2MG was 4.82 times higher in subjects with both over the median levels of U-As (85.1 μg L(-1)) and urinary Pb (18.9 μg L(-1)) as compared to both lower than the median (p<0.001). These results indicate that U-As might relate to renal dysfunction even other important risk factors were taken into account. Follow-up studies for causal inference are warranted.

Arsenic methylation, GSTO1 polymorphisms, and metabolic syndrome in an arseniasis endemic area of southwestern Taiwan

Previous studies have shown that hair arsenic (As) levels are associated with an increased prevalence of metabolic syndrome (MetS), which is a strong predictor for type 2 diabetes. The objective of this study was to evaluate whether urinary arsenic methylation is related to MetS in an arseniasis endemic area of southwestern Taiwan, taking genetic factors into account. Subjects were from a community-based cohort recruited in 1990 from three villages in Putai Township. In 2002-2003, we successfully followed 247 subjects and measured their urinary arsenic species including inorganic arsenic, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), as well as the coding region polymorphisms of three genes known to involve in arsenic methylation. Results showed that subjects of MetS had a history of consuming well water of higher arsenic concentration as compared to those without MetS. We also found a significant association between urinary arsenic species and risk for MetS, where the odds ratio of MetS was increased with decreasing proportion of MMA and low rate of primary methylation (defined as MMA/inorganic As). The increased risk associated with low primary methylation rate was further modified by the GSTO1 A140D polymorphism, with the D allele carriers showing a slightly higher risk for MetS. Our results suggest that a low MMA% is associated with increased risk for MetS among As-exposed subjects and the genetic polymorphism of GSTO1, an enzyme responsible for the reduction of pentavalent arsenic species, may also play a modest modification role.

Risk of carotid atherosclerosis is associated with low serum paraoxonase (PON1) activity among arsenic exposed residents in Southwestern Taiwan.

To understand whether human paraoxonase 1 (PON1) would modulate the risk for arsenic-related atherosclerosis, we studied 196 residents from an arseniasis-endemic area in Southwestern Taiwan and 291 age- and sex-matched residents from a nearby control area where arsenic exposure was found low. Carotid atherosclerosis was defined by a carotid artery intima-media wall thickness (IMT) of >1.0 mm. Prevalence of carotid atherosclerosis was increased in the arseniasis-endemic area as compared to the control area after adjustment for conventional risk factors (OR=2.20, p<0.01). The prevalence was positively associated with cumulative arsenic exposure (mg/L-year) in a dose-dependent manner. Multiple logistic regression analysis showed that in the endemic group, low serum PON1 activity was an independent risk factor for atherosclerosis (OR=4.18 low vs. high, p<0.05). For those of low PON1 activity and high cumulative arsenic exposure, the odds ratio for the prevalence of atherosclerosis was further increased up to 5.68 (p<0.05). No significant association was found between atherosclerosis and four polymorphisms of the PON gene cluster (PON1 -108C/T, PON1 Q192R, PON2 A148G, PON2 C311S). However, genetic frequencies of certain alleles including PON1 Q192, PON2 G148 and PON2 C311 were found increased in the endemic group as compared to the controls and a general Chinese population, indicating a possible survival selection in the endemic group after a long arsenic exposure history. Our results showed a significant joint effect between arsenic exposure and serum PON1 activity on carotid atherosclerosis, suggesting that subjects of low PON1 activity may be more susceptible to arsenic-related cardiovascular disease.

Effect of Nanoparticles Exposure on Fractional Exhaled Nitric Oxide (FENO) in Workers Exposed to Nanomaterials

Fractional exhaled nitric oxide (FENO) measurement is a useful diagnostic test of airway inflammation. However, there have been few studies of FENO in workers exposed to nanomaterials. The purpose of this study was to examine the effect of nanoparticle (NP) exposure on FENO and to assess whether the FENO is increased in workers exposed to nanomaterials (NM). In this study, both exposed workers and non-exposed controls were recruited from NM handling plants in Taiwan. A total of 437 subjects (exposed group = 241, non-exposed group = 196) completed the FENO and spirometric measurements from 2009–2011. The authors used a control-banding (CB) matrix to categorize the risk level of each participant. In a multivariate linear regression analysis, this study found a significant association between risk level 2 of NP exposure and FENO. Furthermore, asthma, allergic rhinitis, peak expiratory flow rate (PEFR), and NF-κB were also significantly associated with FENO. When the multivariate logistic regression model was adjusted for confounders, nano-TiO2 in all of the NM exposed categories had a significantly increased risk in FENO > 35 ppb. This study found associations between the risk level of NP exposure and FENO (particularly noteworthy for Nano-TiO2). Monitoring FENO in the lung could open up a window into the role nitric oxide (NO) may play in pathogenesis.

Synergistic effect of polymorphisms of paraoxonase gene cluster and arsenic exposure on electrocardiogram abnormality.

Arsenic has been linked to increased prevalence of cancer and cardiovascular disease (CVD), but the long-term impact of arsenic exposure remains unclear. Human paraoxonase (PON1) is a high-density lipoprotein-associated antioxidant enzyme which hydrolyzes oxidized lipids and is thought to be protective against atherosclerosis, but evidence remains limited to case-control studies. Only recently have genes encoding enzymes responsible for arsenic metabolism, such as AS3MT and GSTO, been cloned and characterized. This study was designed to evaluate the synergistic interaction of genetic factors and arsenic exposure on electrocardiogram abnormality. A total of 216 residents from three tap water implemented villages of previous arseniasis-hyperendemic regions in Taiwan were prospectively followed for an average of 8 years. For each resident, a 12-lead conventional electrocardiogram (ECG) was recorded and coded by Minnesota Code standard criteria. Eight functional polymorphisms of PON1, PON2, AS3MT, GSTO1, and GSTO2 were examined for genetic susceptibility to ECG abnormality. Among 42 incident cases with ECG deterioration identified among 121 baseline-normal subjects, arsenic exposure was significantly correlated with incidence of ECG abnormality. In addition, polymorphisms in two paraoxonase genes were also found associated with the incidence of ECG abnormality. A haplotype R-C-S constituted by polymorphisms of PON1 Q192R, -108C/T and PON2 C311S was linked to the increased risk. Subjects exposed to high levels of As (cumulative As exposure >14.7 ppm-year or drinking artesian well water >21 years) and carrying the R-C-S haplotype had significantly increased risks for ECG abnormality over those with only one risk factor. Results of this study showed a long-term arsenic effect on ECG abnormality and significant gene-gene and gene-environment interactions linked to the incidence of CVD. This finding might have important implications for a novel and potentially useful biomarker of arsenic risk.

Elevated lactate dehydrogenase activity and increased cardiovascular mortality in the arsenic-endemic areas of southwestern Taiwan

Arsenic ingestion has been linked to increasing global prevalence of and mortality from cardiovascular disease (CVD); arsenic can be removed from drinking water to reduce related health effects. Lactate dehydrogenase (LDH) is used for the evaluation of acute arsenic toxicity in vivo and in vitro, but it is not validated for the evaluation of long-term, chronic arsenic exposure. The present study examined the long-term effect of chronic arsenic exposure on CVD and serum LDH levels, after consideration of arsenic metabolism capacity. A total of 380 subjects from an arseniasis-endemic area and 303 from a non-endemic area of southwestern Taiwan were recruited in 2002. Various urinary arsenic species were analyzed using high-performance liquid chromatography (HPLC) and hydride generation systems. Fasting serum was used for quantitative determination of the total LDH activity. A significant dose-response relationship was observed between arsenic exposure and LDH elevation, independent of urinary arsenic profiles (P<0.001). Furthermore, abnormal LDH elevation was associated with CVD mortality after adjustment for Framingham risk scores for 10-year CVD and arsenic exposure (hazard ratio, 3.98; 95% confidence interval, 1.07-14.81). LDH was elevated in subjects with arsenic exposure in a dose-dependent manner. LDH is a marker of arsenic toxicity associated with CVD mortality. Results of this study have important implications for use in ascertaining long-term arsenic exposure risk of CVD.

185 Four-year follow-up study of health hazards among workers handling engineered nanomaterials

Objectives The aim of this study was to investigate the health hazards in workers exposed to nanoparticles during manufacturing and application of nanomaterials. Methods For this 4-year longitudinal study, we recruited 283 nanomaterial-handling workers and 213 non-exposed control workers from 15 manufacturing plants in Taiwan. Follow-up measurements were done at 6, 12, 24, 36, and 48 months. Among them, 206 nanomaterial-handling workers and 140 unexposed workers were followed up for more than twice. For each participant, a self-administered questionnaire was distributed to collect work history and personal habits after informed consent. Since there was a lack of equipment for personal sampling and summary index for mixed exposure, we adopted the control banding nanotool risk level matrix to categorise the risk level for each participant. Blood, urine and exhaled breath condensate (EBC) were collected to examine markers of cardiopulmonary injuries, lung and systemic inflammation, oxidative stress, and genotoxicity. Generalised Estimating Equation (GEE) model was applied to analyse these repeated measurements. Results There were 108 workers in risk level 1, and 91 workers in risk level 2, and 7 in risk level 3. Although depression of antioxidant enzymes and increase of cardiovascular markers were found in the cross-sectional and early follow-up study, no significant difference was revealed between exposed workers and controls in the changes of biomarkers in this 4-year longitudinal study. The non-significant markers included lung injuries markers, cardiovascular disease markers, heart rate variability (HRV), inflammation markers, oxidative stress and lipid peroxidation markers, comet assay, pulmonary function test, and neurobehavioral function test. Conclusions This longitudinal study suggests that there was no evidence of health hazards among nanomaterials handling workers. The preliminary survey of nanoparticle exposure level in the workplace was quite low. Such exposure level was not high enough to induce systemic health effects in nanoworkers.

10 The association between paraoxonase (PON1) polymorphisms and cardiovascular injuries among nanoworkers

Objectives The market of nanomaterials products is rapidly expanding. The lack of scientific evidence describing accompanying exposure and cardiovascular health risks regarding its guidance and regulation. The objectives of this study was to examine (1) the association between different nanomaterials exposure and cardiovascular biomarkers and (2) effect of PON1 Q192R genetic polymorphism on cardiovascular biomarkers among nanoworkers. Methods In this cross-sectional study, we recruited 258 workers exposed to nanomaterials and 200 non-exposed controls from 14 nanomaterial handling plants in Taiwan from 2009 to 2011. The non-exposed controls were selected from the same plants, but they did not handle nanomaterials. We used the control banding matrix to categorize the risk level of nanoworkers. For each participant, we collected blood specimens to measure cardiovascular biomarkers and genotyping of PON1 (Q192R). In addition, heart rate variability (HRV) was tested. Results PON1 Q192R genetic polymorphism associated with PON1 activity and HRV (SDNN, RMSSD, and TP). We also found that different nanomaterials exposure affected particular cardiovascular biomarkers by controlling PON1 Q192R genetic polymorphism. Such as nano-carbon tube exposure resulted in a decrease in fibrinogen. Nano-SiO2, nano-TiO2 and nano-Ag exposure separately resulted in an increase in fibrinogen, VCT and RMSSD. Conclusion This study adopted comprehensive cardiovascular examinations to establish the association between different nanomaterials exposure and cardiovascular injuries. We also found possible causal associations that NPs may activate the autonomic nervous system and result in alterations of heart rate variability. Additionally, PON1 Q192R genetic polymorphisms were significant variables for PON1 activity and HRV.