Risk of human health by particulate matter as a source of air pollution--comparison with tobacco smoking

Dietary L-Tryptophan consumption determines the number of colonic regulatory T cells and susceptibility to colitis via GPR15

Environmental factors are the major contributor to the onset of immunological disorders such as ulcerative colitis. However, their identities remain unclear. Here, we discover that the amount of consumed L-Tryptophan (L-Trp), a ubiquitous dietary component, determines the transcription level of the colonic T cell homing receptor, GPR15, hence affecting the number of colonic FOXP3+ regulatory T (Treg) cells and local immune homeostasis. Ingested L-Trp is converted by host IDO1/2 enzymes, but not by gut microbiota, to compounds that induce GPR15 transcription preferentially in Treg cells via the aryl hydrocarbon receptor. Consequently, two weeks of dietary L-Trp supplementation nearly double the colonic GPR15+ Treg cells via GPR15-mediated homing and substantially reduce the future risk of colitis. In addition, humans consume 3-4 times less L-Trp per kilogram of body weight and have fewer colonic GPR15+ Treg cells than mice. Thus, we uncover a microbiota-independent mechanism linking dietary L-Trp and colonic Treg cells, that may have therapeutic potential.

Contribution of toxicologic pathologists for the safety of human health in biomedical research-past, present, and future of the JSTP

The research field of “Toxicologic Pathology” evaluates potentially toxic chemical exposures and chemically mediated illnesses in humans and experimental animals. Comparative studies of chemical exposures between model organisms and humans are essential for the risk assessment of chemicals and human health. Here we review the development and activities of the Japanese Society of Toxicologic Pathology (JSTP) during its 37-year history. Toxicological pathology studies provide many interesting and valuable findings. Rodent cancer bioassay data demonstrate the importance of dose levels, times, and duration of exposures to chemicals that possibly cause human cancers. Studies of toxic injuries in the nasal cavity demonstrate that specific chemical compounds affect different target cells and tissues. These observations are relevant for current air pollution studies in the preventive medicine field. Future toxicological pathology studies will be enhanced by applying molecular pathology with advanced observation techniques. In addition to the nasal cavity, another sense organ such as the tongue should be a potential next program of our mission for risk assessment of inhaled and ingested chemicals. As a message to the younger members of the JSTP, interdisciplinary and global cooperation should be emphasized. Elucidating the mechanisms of toxicologic pathology with a combination of advanced expertise in genetics and molecular biology offers promise for future advances by JSTP members.

Occupational Exposure to Pesticides and Lung Cancer Risk: A Propensity Score Analyses

Purpose

Occupational exposure to pesticides is thought to be associated with lung cancer, but studies have yielded conflicting results. We performed a propensity score (PS) based analyses to evaluate the relationship between occupational exposure to pesticides and lung cancer risk in the Korea National Cancer Center community-based cohort study (KNCCCS).

Materials and Methods

During the follow-up period, 123 incidental lung cancer cases were identified, of the 7,471 subjects in the final statistical analysis. Information about occupational exposure to pesticides and other factors was collected at enrollment (2003–2010). Cox proportional hazards regression analyses were conducted. Four PS-based approaches (i.e., matching, stratification, inverse probability-of-treatment weighting, and the use of the PS as a covariate) were adopted, and the results were compared. PS was obtained from the logistic regression model. Absolute standardized differences according to occupational exposure to pesticides were provided to evaluate the balance in baseline characteristics.

Results

In the Cox proportional hazards regression model, the hazard ratio (HR) for lung cancer according to occupational exposure to pesticides was 1.82 (95% confidence interval [CI], 1.11 to 2.98). With all the propensity score matching (PSM) methods, the HRs for lung cancer based on exposure to pesticides ranged from 1.65 (95% CI, 1.04 to 2.64) (continuous term with PSM) to 2.84 (95% CI, 1.81 to 4.46) (stratification by 5 strata of the PS). The results varied slightly based on the method used, but the direction and statistical significance remained the same.

Conclusion

Our results strengthen the evidence for an association between occupational exposure to pesticides and the risk of lung cancer.

Study on performance of electrostatic precipitator under multi-physics coupling

A wire-plate electrostatic precipitator (ESP) is developed to analyze the particle transport characteristics and the influence of various factors on the performance of ESP. Above all, an experimental device is built to measure the current density distribution of the plates and obtain good consistency with the numerical simulation results, taking the ESP model established by COMSOL/Multiphysics as the numerical simulating object. Firstly, the electric field is solved by finite element method(FEM) to obtain the potential and charge density distribution. Then, the influence of secondary flow on the main flow at different flow velocities is explored. Finally, multi-physics coupling calculations show the influence of dust particle properties, electrode configuration, and operating conditions on ESP performance. The study found that the particle diameter is positively correlated with its charge, force, and motion, and the relative permittivity of the particles affects the collecting efficiency by affecting its charge difficulty. The wire-to-wire spacing is not proportional to collecting efficiency, when the spacing is 80 mm, the efficiency and the corona current can be maximized. Average electric field strength, corona current density, and current density distribution standard deviation satisfy the cubic function relationship. In addition, the effect of airflow velocity on collecting efficiency and particle precipitation is revealed. It provides a valuable basis for design and performance optimization of ESP.

Does CYP2E1 RsaI/PstI polymorphism confer head and neck carcinoma susceptibility?: A meta-analysis based on 43 studies

BACKGROUND

Previous reports showed that CYP2E1 RsaI/PstI polymorphism may be a risk factor for cancers. Published meta-analyses in 2010 and 2011, respectively, on the relationship of CYP2E1 RsaI/PstI polymorphisms with the susceptibility to head and neck carcinoma (HNC) have generated inconsistent results. Thus, this study aimed to conduct an updated meta-analysis involving published studies up to Nov 2015 to get a more confidential result.

METHODS

Eligible studies up to Nov 2015 were retrieved and screened. Data were extracted and a quantitative meta-analysis was conducted. Subgroup analyses on ethnicity, source of controls, sample size, genotyping method, smoking status, and drinking status were also performed.

RESULTS

Forty-one publications including a total of 43 case-control studies were selected for analysis. The overall data under a homozygote comparison model indicated a significant association of CYP2E1 RsaI/PstI polymorphisms with HNC risk (c2c2 vs c1c1: odds ratio [OR] = 1.97; 95% confidence interval [CI] = 1.53-2.53). Similar results were observed in the Asian subgroup (c2c2 vs c1c1: OR = 1.98; 95%CI = 1.51-2.60; c2 vs c1: OR = 1.20; 95%CI = 1.03-1.39) and mixed population (c2 vs c1: OR = 1.41; 95%CI = 1.06-1.86) when the data were stratified by ethnicities. Interestingly, increased cancer risk only was shown among never-smokers (c2c2+c1c2 vs c1c1: OR = 1.44; 95%CI = 1.05-1.98) but not ever-smokers.

CONCLUSION

CYP2E1 RsaI/PstI polymorphisms may modify the susceptibility to HNC, particularly among Asians, mixed population, and never-smokers. Future large and well-designed studies are needed to verify this conclusion.

4-Hydroxynonenal: A Superior Oxidative Biomarker Compared to Malondialdehyde and Carbonyl Content Induced by Carbon Tetrachloride in Rats

Carbon tetrachloride (CCl4), a halogenated substance that generates free radical species during metabolism in vivo, induces hepatotoxicity, produces oxidative DNA damage, and increased levels of protein carbonyl, malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE). In this study, Sprague-Dawley rats received single or repeated ip injections of carbon tetrachloride (CCl4), and formation and persistence of carbonyls, MDA, and 4-HNE in plasma were measured using gas chromatography-mass spectrometry. After a single injection of 500 mg/kg CCl4 the in vivo half-lives of MDA and carbonyl content were 1.5 d and 2 d, respectively, while that of 4-HNE was approximately 10 d. Treatment with CCl4 (50, 100, 500, or 1000 mg/kg) dose-dependently increased these oxidative biomarkers in blood. However, formation of protein carbonyls and MDA was less sensitive than 4-HNE to CCl4. Levels of serum glutamic oxaloacetic transaminase (SGOT) and glutamic pyruvic transaminase (SGPT) (hepatotoxicity markers) rose with CCl4 doses. After a single injection (500 mg/kg), the peak level of SGOT was observed after 8 h but SGPT after 24 h. Overall, 4-HNE was more dose-sensitive and showed greater formation subchronically than other biomarkers. Multiple ip treatments with 300 mg CCl4 /kg (d 1, 3, 6, 10, 14, and 21) demonstrated that 4-HNE formation was highest (18-fold, peak/control) and subchronic up to d 21 (last treatment day), unlike other biomarkers. Data suggest that 4-HNE, MDA, and carbonyl content may be useful oxidative biomarkers for exposure to free radical generating halogenated compounds. However, 4-HNE appears to be a more sensitive and sustainable biomarker for toxicological and risk assessments.

Hierarchical Composites to Reduce N-Nitrosamines in Cigarette Smoke

In order to reduce the harmful constituents in cigarette smoke, two hierarchical composites were synthesized. Based on, zeolites HZSM-5 or NaY fragments were introduced into the synthetic system of mesoporous silica SBA-15 or MCM-41 and assembled with the mesoporous materials. These porous composites combine the advantages of micro- and mesoporous materials, and exhibit higher effects than activated carbon on reducing tobacco specific nitrosamines (TSNA) and some vapor phase compounds in smoke.

Urinary 1-hydroxypyrene is associated with oxidative stress and inflammatory biomarkers in acute Myocardial Infarction

Several studies have associated exposure to environmental pollutants, especially polycyclic aromatic hydrocarbons (PAHs), with the development of cardiovascular diseases. Considering that 1-hydroxypyrene (1-OHP) is the major biomarker of exposure to pyrenes, the purpose of this study was to evaluate the potential association between 1-OHP and oxidative stress/inflammatory biomarkers in patients who had suffered an acute myocardial infarction (AMI). After adopting the exclusion criteria, 58 post-infarction patients and 41 controls were sub-divided into smokers and non-smokers. Urinary 1-OHP, hematological and biochemical parameters, oxidative stress biomarkers (MDA, SOD, CAT, GPx and exogenous antioxidants) and the inflammatory biomarker (hs-CRP) were analyzed. 1-OHP levels were increased in post-infarct patients compared to controls (p < 0.05) and were correlated to MDA (r = 0.426, p < 0.01), CAT (r = 0.474, p < 0.001) and β-carotene (r = -0.309; p < 0.05) in non-smokers. Furthermore, post-infarction patients had elevated hs-CRP, MDA, CAT and GPx levels compared to controls for both smokers and non-smokers. Besides, β-carotene levels and SOD activity were decreased in post-infarction patients. In summary, our findings indicate that the exposure to pyrenes was associated to lipid damage and alterations of endogenous and exogenous antioxidants, demonstrating that PAHs contribute to oxidative stress and are associated to acute myocardial infarction.

Laryngeal cancer in Kazakhstan - ethnic, age and gender differences over time

The purpose of the present study was to provide an assessment of the incidence of cancer of the larynx in Kazakhstan with especial attention to ethnicity and gender, as well as age. The retrospective design covered all new cases of laryngeal cancer in 11 years (1999-2009). The total number was 4,967 cases, 4,535 (91.3%) in males and 432 (8.7%) in women, with a gender ratio of 10.5:1. Patients of Kazakh (31.2%) and Russian (51.4%) ethnicity accounted for the vast majority (82.6%), with Russians predominating in both sexes, but particularly in females. Age peak in Kazakhs was 70 years and older (14.6 ± 0.70/0000), and in Russians was 60-69 years (21.6 ± 1.30/0000). In the dynamics, the rates had the tendency to decrease more markedly in Russian than Kazakh men, especially in the younger groups, while increase was noted in the youngest females of both ethnicities, but again greater in Russians, presumably reflecting change in underlying lifestyle factors.

Subchronic oral administration of Benzo[a]pyrene impairs motor and cognitive behavior and modulates S100B levels and MAPKs in rats

Benzo[a]pyrene (BaP) is an environmental contaminant produced during incomplete combustion of organic material that is well known as a mutagenic and carcinogenic toxin. There are few studies addressing the molecular and cellular basis of behavioural alterations related to BaP exposure. The aim of this study was to evaluate the effect of subchronic oral administration of BaP on behavioral and neurochemical parameters. Wistar male rats received BaP (2 mg/kg) or corn oil (control), once a day for 28 days (n = 12/group). Spontaneous locomotor activity and short- and long-term memories were evaluated. Glial fibrillary acid protein and S100B content in the hippocampus, serum and CSF were measured using ELISA and total and phosphorylated forms of mitogen activated protein kinases (MAPKs) named extracellular signal-regulated kinases 1 and 2, p38(MAPK) and c-Jun amino-terminal kinases 1 and 2, in the hippocampus, were evaluated by western blotting. BaP induced a significant increase on locomotor activity and a decrease in short-term memory. S100B content was increased significantly in cerebrospinal fluid. BaP induced a decrease on ERK2 phosphorylation in the hippocampus. Thus, BaP subchronic treatment induces an astroglial response and impairs both motor and cognitive behavior, with parallel inhibition of ERK2, a signaling enzyme involved in the hippocampal neuroplasticity. All these effects suggest that BaP neurotoxicity is a concern for environmental pollution.

Occupational pesticide exposures and respiratory health

Pesticides have been widely used to control pest and pest-related diseases in agriculture, fishery, forestry and the food industry. In this review, we identify a number of respiratory symptoms and diseases that have been associated with occupational pesticide exposures. Impaired lung function has also been observed among people occupationally exposed to pesticides. There was strong evidence for an association between occupational pesticide exposure and asthma, especially in agricultural occupations. In addition, we found suggestive evidence for a link between occupational pesticide exposure and chronic bronchitis or COPD. There was inconclusive evidence for the association between occupational pesticide exposure and lung cancer. Better control of pesticide uses and enforcement of safety behaviors, such as using personal protection equipment (PPE) in the workplace, are critical for reducing the risk of developing pesticide-related symptoms and diseases. Educational training programs focusing on basic safety precautions and proper uses of personal protection equipment (PPE) are possible interventions that could be used to control the respiratory diseases associated with pesticide exposure in occupational setting.

Epidemiological evaluation of laryngeal cancer incidence in Kazakhstan for the years 1999-2009

The purpose was to provide a descriptive epidemiological assessment of the incidence of cancer of the larynx in Kazakhstan and spatial evaluation with gender characteristics. This retrospective study covered all new cases of laryngeal cancer in 11 years (1999-2009). The total number was 4,967 cases, 4,535 (91.3%) in males and 432 (8.7%) in women, with a ratio of 10.5:1. The higher incidence in men compared to women was evident in all age groups, the differences being statistically significant (p<0.05). At the same time revealed a unimodal growth with age, peaking at 70 years and older both sexes. In the dynamics, incidence rates of laryngeal cancer demonstrated a tendency to decrease, in women (T=-6.7%) this being more pronounced than in men (T=-3.3%). Levels were determined to produce cartograms of cancer of the larynx for male and female populations, clear geographical variation being evidenced. The data are discussed with reference to possible risk factors.

Characteristics of the transformation frequency at the tumor promotion stage of airborne particulate and gaseous matter at ten sites in Japan

We used a high-volume air sampler in the summer of 2007 and the winter of 2008 at ten Japanese sites (Sapporo, Sendai, Maebashi, Tsukuba, Shinjuku, Sagamihara, Shizuoka, Touhaku, Kitakyushu, and Kagoshima) to collect total suspended particulate (TSP) and gaseous matter for evaluation. We evaluated the transformation frequency at the tumor promotion stage of these samples in a cell transformation assay using Bhas 42 cells, which were established from BALB/c 3T3 cells transfected with the v-Ha-ras oncogene. All samples collected from the gaseous matter were negative for transformed foci. There were several patterns of transformation frequency at the tumor promotion stage by area for the TSP samples. At Sapporo, the transformation frequency at the tumor promotion stage was remarkably higher in winter than in summer as well as in winter at the other sites. At six urban cities from Sendai to Shizuoka, the levels of transformed frequencies per μg of suspended particulates in winter were almost the same, and were higher than those of the remaining three sites. At three sites, Touhaku, Kitakyushu and Kagoshima, the transformation results in winter were judged as negative. The characteristics of the transformed frequencies of the compounds adsorbed on particulate matter at the sampling sites were significant in winter. We also studied the correlation between the transformation frequency at the tumor promotion stage of the TSP samples and the results of quantitative analysis of 16 polyaromatic hydrocarbons (PAHs) at the ten sites. We found that the transformation frequency at the tumor promotion stage of airborne samples could not be predicted based on the quantitative results of the PAHs in those samples. These data suggest that direct risk assessment of air samples with a bioassay is more valuable than quantitative analysis of compounds such as PAHs for predicting carcinogenicity.

Identifying at-risk communities for action on cancer prevention: a case study in new brunswick (Canada) communities

Health statistics reported by large geographic area such as province, state, county or health region offer little insight into disease conditions at the community level where people live and work, where occupational and environmental exposures occur, and where industrial emissions are often concentrated. This study investigated overall patterns of cancer incidence and socioeconomic status (SES) among 14 communities in the province of New Brunswick (Canada). A multivariate ordination technique, hierarchical clustering, and permutation procedures were used to identify and test significance of community clusters and whether the overall pattern of SES was correlated with patterns of cancer among communities. Communities with significantly high or significantly low overall rates of cancers were identified, patterns that were not related to SES. The potential influence of age, small populations, diagnostic screening, smoking and environmental risk factors contributing to locally elevated cancer rates are discussed. Cancer incidence reported at smaller spatial scales provides health officials and researchers with a basis for identifying communities potentially at-risk and aids in the development of appropriate community-based risk reduction actions and cancer prevention.

Toxicity evaluation of benzo[a]pyrene on the polychaete Perinereis nuntia using subtractive cDNA libraries

To gain insight into the toxic effects of the carcinogenic PAH benzo[a]pyrene (BaP) on the typical marine benthic polychaete Perinereis nuntia, we amplified and sequenced genes by creating subtractive cDNA libraries between worms exposed to BaP and solvent control. We assigned functions to the identified sequences and further analyzed the transcriptional profile changes of a set of 50 selected potential marker genes using quantitative real time PCR. A total of 2422 new high quality ESTs (GenBank accession number GT629654-GT632075) were obtained in the P. nuntia subtracted cDNA libraries, and assembled into 1594 unique sequences. Blastx results showed 700 of the unique sequences shared high similarity with existing genes in the GenBank nr database. Functional annotation of these enriched gene segments suggested that P. nuntia shows a wide range of toxicological responses to BaP. Comparison of the transcriptional profiles of the 50 potential marker genes in worms exposed to BaP and the control suggested that BaP significantly changed the expression of genes involved in xenobiotics metabolism, reactive oxygen species (ROS) elimination, DNA repair, apoptosis, cell division cycle, neurodegeneration, neurotransmitter metabolism and carcinogenesis. It also shows that there are significant correlations between these potential marker genes. The results support the prediction that the polychaete P. nuntia also has a set of tumor-related genes, while other responses influenced by BaP involve detoxification, antioxidation, DNA repair and apoptosis.

Overexpression of antioxidant enzymes in ApoE-deficient mice suppresses benzo(a)pyrene-accelerated atherosclerosis

The carcinogenic polycylic aromatic hydrocarbon, benzo(a)pyrene (BaP), has been shown to generate reactive oxygen species (ROS) and accelerate the development of atherosclerosis. To assess the causal role of BaP-generated ROS in this process, we evaluated atherosclerotic metrics in apolipoprotein E-deficient (ApoE(-/-)) mice with or without overexpression of Cu/Zn-superoxide dismutase (Cu/Zn-SOD) and/or catalase. Without BaP, aortic atherosclerotic lesions were smaller in ApoE(-/-) mice overexpressing catalase or both Cu/Zn-SOD and catalase than in those overexpressing neither or Cu/Zn-SOD only. After treating with BaP or vehicle for 24 weeks, mean lesion sizes in the aortic tree and aortic root of ApoE(-/-) mice were increased by approximately 60% and 40%, respectively. BaP also increased the levels of oxidized lipids in the aortic tree of ApoE(-/-) mice and increased the frequency of advanced lesions. In contrast, BaP did not significantly alter lipid peroxidation levels or atherosclerotic lesions in the aortas of ApoE(-/-) mice overexpressing Cu/Zn-SOD and/or catalase. Overexpression of Cu/Zn-SOD and/or catalase also inhibited BaP-induced expression of cell adhesion molecules in aortas and endothelial cells, and reduced BaP-induced monocyte adhesion to endothelial cells. These observations, together with the functions of catalase and Cu/Zn-SOD to scavenge hydrogen peroxide and superoxide anions, implicate a causal role of ROS in the pathogenesis of BaP-induced atherosclerosis.

Mortality due to lung, laryngeal and bladder cancer in towns lying in the vicinity of combustion installations

BACKGROUND

Installations that burn fossil fuels to generate power may represent a health problem due to the toxic substances which they release into the environment.

OBJECTIVES

To investigate whether there might be excess mortality due to tumors of lung, larynx and bladder in the population residing near Spanish combustion installations included in the European Pollutant Emission Register.

METHODS

Ecologic study designed to model sex-specific standardized mortality ratios for the above three tumors in Spanish towns, over the period 1994-2003. Population exposure to pollution was estimated on the basis of distance from town of residence to pollution source. Using mixed Poisson regression models, we analyzed: risk of dying from cancer in a 5-kilometer zone around installations that commenced operations before 1990; effect of type of fuel used; and risk gradient within a 50-kilometer radius of such installations.

RESULTS

Excess mortality (relative risk, 95% confidence interval) was detected in the vicinity of pre-1990 installations for lung cancer (1.066, 1.041-1.091 in the overall population; 1.084, 1.057-1.111 in men), and laryngeal cancer among men (1.067, 0.992-1.148). Lung cancer displayed excess mortality for all types of fuel used, whereas in laryngeal and bladder cancer, the excess was associated with coal-fired industries. There was a risk gradient effect in the proximity of a number of installations.

CONCLUSIONS

Our results could support the hypothesis of an association between risk of lung, laryngeal and bladder cancer mortality and proximity to Spanish combustion installations.