Synergistic impaired effect between smoking and manganese dust exposure on pulmonary ventilation function in Guangxi manganese-exposed workers healthy cohort (GXMEWHC)

Activation of ERK/NF-kB Pathways Contributes to the Inflammatory Response in Epithelial Cells and Macrophages Following Manganese Exposure

Different types of metals, including manganese (Mn), are constantly encountered in various environmental matrices due to natural and anthropogenic activities. They induce a sustained inflammatory response in various organs, which is considered to be an important priming event in the pathogenesis of several diseases. Mn-induced neuroinflammation and subsequent neurodegeneration are well recognized. However, emerging data suggest that occupationally and environmentally relevant levels may affect various organs, including the lungs. Therefore, the present study was carried out to investigate the effects of Mn (as Mn2+) exposure on the inflammatory response in human normal bronchial (BEAS-2B) and adenocarcinoma alveolar basal (A549) epithelial cells, as well as in murine macrophages (J774). Mn2+ exposure significantly induced mRNA and protein expression of various pro-inflammatory mediators (cytokines and chemokines) in all cells compared to corresponding vehicle controls. Furthermore, Mn2+ treatment also led to increased phosphorylation of extracellular-signal-regulated kinase (ERK)1/2 and nuclear factor-kappa B (NF-kB) p65 in both epithelial cells and macrophages. As expected, cells treated with inhibitors of ERK1/2 (PD98059) and NF-kB p65 (IMD0354) effectively mitigated the expression of various pro-inflammatory mediators induced by Mn2+, suggesting that ERK/NF-kB pathways have a critical role in the Mn2+-induced inflammatory response. Further, in vivo studies are required to confirm these in vitro findings to support clinical translation.

The association between multi-heavy metals exposure and lung function in a typical rural population of Northwest China

BACKGROUND

Heavy metal exposure is acknowledged to be associated with decrease of lung function, but the relationship between metals co-exposure and lung function in rural areas of Northwest China remains unclear, particularly in an area famous for heavy metal pollution and solid fuel use. Therefore, the purpose of this study is to explore the effects of heavy metal exposure on lung function and the potential impacts of living habit in a rural cohort of Northwest China.

METHODS

The study area included five villages of two regions in Northwestern China-Gansu province. All participants were recruited from the Dongdagou-Xinglong (DDG-XL) rural cohort in the study area. Urine levels of 10 common and representative heavy metals were detected by ICP-MS, including Cobalt (Co), Nickel (Ni), Molybdenum (Mo), Cadmium (Cd), Stibium (Sb), Copper (Cu), Zinc (Zn), Mercury (Hg), Lead (Pb), and Manganese (Mn). The lung function was detected by measuring percentages of predicted forced vital capacity (FVC%) and predicted forced expiratory volume in one second (FEV1%) as well as the ratio of FEV1/FVC. We also analyzed the association between heavy metals and pulmonary ventilation dysfunction (PVD). Restricted cubic spline, logistic regression, linear regression, and bayesian kernel machine regression (BKMR) model were used to analyze the relationship between heavy metal exposure and lung function.

RESULTS

Finally, a total of 382 participants were included in this study with an average age of 56.69 ± 7.32 years, and 82.46% of them used solid fuels for heating and cooking. Single metal exposure analysis showed that the higher concentration of Hg, Mn, Sb, and lower Mo may be risk factors for PVD. We also found that FEV1% and FVC% were negatively correlated with Sb, Hg, and Mn, but positively correlated with Mo. The effect of mixed heavy metals exposure could be observed through BKMR model, through which we found the lung function decreased with the increase of heavy metal concentration. Furthermore, the males, BMI ≥ 24 kg/m2 and who used solid fuels showed a higher risk of PVD when exposed to Co, Zn, and Hg.

CONCLUSIONS

Our results suggested that heavy metal exposure was associated with decrease of lung function regardless of single exposure or mixed exposure, particularly for Sb, Hg, Mn and those who use solid fuels.

Adverse pulmonary effects after oral exposure to copper, manganese and mercury, alone and in mixtures, in a Spraque-Dawley rat model

The rise in respiratory disease has been attributed to an increase in environmental pollution. Heavy metals contribute to environmental contamination via air, water, soil and food. The effects of atmospheric exposure to heavy metals on pulmonary structure and function have been researched, but the effects through drinking water have been neglected. The aim of this study was to investigate the potential in vivo alterations in the pulmonary tissue of male Sprague-Dawley rats after a 28-day oral exposure to copper (Cu), manganese (Mn) and mercury (Hg), alone and in mixtures, at 100 times the World Health Organization's (WHO) safety limit for each heavy metal in drinking water. Forty-eight male Sprague-Dawley rats were randomly divided into eight groups (n = 6): control, Cu, Mn, Hg, Cu + Mn, Cu + Hg, Mn + Hg and Cu, Mn + Hg. The morphology of lung tissue and the bronchioles were evaluated using light- and transmission electron microscopy. For all exposed groups, morphological changes included thickened inter- and intra-alveolar spaces, stratified epithelium, disrupted smooth muscle and early fibrosis and desquamation of the epithelia of the bronchioles to varying degrees. In all exposed groups, ultrastructurally, an increase in disarranged collagen and elastin fibers, nuclear membrane detachment, chromatin condensation, indistinct nucleoli and an increase in collagen fiber disarrangement was observed. This study has identified that oral exposure to Cu, Mn and Hg and as part of mixtures caused pathogenesis due to inflammation, cellular damage and fibrosis with Mn + Hg being the most potent heavy metal group.

Respiratory health disorders among workers in some Egyptian welding enterprises

Welding fumes contain a complex mixture of metallic oxides that pose a risk to welders' respiratory systems. This study aimed to evaluate respiratory health disorders among workers in some Egyptian welding enterprises and their relationship to the workplace environment. This research was performed from January 1^st, 2019 to February 28^th, 2021 in welding enterprises in Birket El-Sabaa, a randomly selected district of Menoufia governorate, Egypt. A cross-sectional comparative study was conducted on 110 welders and 110 non-occupationally exposed subjects. Environmental studies were carried out for total welding fumes, respirable dust, and manganese air levels. Spirometric measures and manganese levels in whole blood were applied. Analysis of the personal air samples revealed that the mean values of welding fumes, respirable dust, and manganese air levels were higher than the international permissible levels. Welders had a higher significant prevalence of respiratory manifestations (rhinitis, cough, expectoration, wheezes, dyspnea, and chronic bronchitis) as well as decreased spirometric measures (FVC%, FEV₁%, FEV₁/FVC%, and FEF_25-75%) than controls. The mean value of whole blood manganese level was statistically significantly higher among welders than that of the controls (3.35 ± 0.5 and 1.81 ± 0.79 ng/mL; respectively). A significant relationship was reported between longer work time and the prevalence of respiratory manifestations and decreased spirometric measurements. The use of masks/respirators was associated with a reduced prevalence of respiratory manifestations. Finally, welders that are exposed to welding fumes at concentrations higher than the permissible levels in welding establishments suffer from adverse respiratory problems, as shown by increased prevalence of respiratory manifestations and lower spirometric measurements. Regular use of high-quality personal protective equipment, especially masks, as well as periodic medical examinations for welders, is highly urged.

Challenges in Diagnosing Occupational Chronic Obstructive Pulmonary Disease

Occupational chronic obstructive pulmonary disease (oCOPD) represents 15–20% of the global burden of this disease. Even if industrial bronchitis has long been known, new occupational hazards continue to emerge and enlarge the number of people exposed to risk. This review discusses the challenges related to the early detection of oCOPD, in the context of new exposures and of limited usage of methods for an efficient disease occupational screening. It underlines that a better translation into clinical practice of the new methods for lung function impairment measurements, imaging techniques, or the use of serum or exhaled breath inflammation biomarkers could add significant value in the early detection of oCOPD. Such an approach would increase the chance to stop exposure at an earlier moment and to prevent or at least slow down the further deterioration of the lung function as a result of exposure to occupational (inhaled) hazards.

The impact of environmental and occupational exposures of manganese on pulmonary, hepatic, and renal functions

Manganese (Mn) is an essential trace element for humans, but long-term environmental or occupational exposures can lead to numerous health problems. Although many studies have identified an association between Mn exposures and neurological abnormalities, emerging data suggest that occupationally and environmentally relevant levels of Mn may also be linked to multiple organ dysfunction in the general population. In this regard, many experimental and clinical studies provide support for a causal link between Mn exposure and structural and functional changes that are responsible for organ dysfunction in major organs like lung, liver, and kidney. The underlying mechanisms suggested to Mn toxicity include altered activities of the components of intracellular signaling cascades, oxidative stress, apoptosis, affected cell cycle regulation, autophagy, angiogenesis, and an inflammatory response. We further discussed the sources and possible mechanisms of Mn absorption and distribution in different organs. Finally, treatment strategies available for treating Mn toxicity as well as directions for future studies were discussed.

Effects of Simultaneous Exposure to Smoking and Welding Fume on Pulmonary Function Tests in Spot Welders

BACKGROUND

The respiratory effects of fume exposure during spot welding may aggravate some environmental risk factors such as tobacco smoking. Fume exposure and smoking have negative effects on pulmonary function tests (PFTs). This study assessed the simultaneous effects of smoking and welding fume on spirometry tests in spot welders.

MATERIALS AND METHODS

This cross-sectional study was conducted on 667 spot welders and 1000 assemblers in an automotive manufacturing plant. Spirometry was carried out on all the participants under standard conditions and according to the American Thoracic Society Clinical Practice Guidelines and indices including FEV1, FVC, FEV1/FVC, FEF 25-75, and PEF were measured and compared between two groups of the study population including workers of spot welding and assembling.

RESULTS

It was found that the effect of simultaneous exposure to smoking and welding fume was aggravated on the PFT indices including the FEV1 percent, FEV1/FVC, the FEV1/FVC percent, the PEF percent, FEF25-75, and the FEF25-75 percent, but not on indices such as FVC, the FVC percent, and PEF.

CONCLUSION

Simultaneous exposure to smoking and welding fume resulted in a reduction in some spirometry indices, causing respiratory airway obstruction in the spot welders. Occupational safety and regular medical examinations with shorter intervals in smoking spot welders can prevent acute respiratory effects of exposure to smoking and welding fume.

Occupational exposure to manganese and risk of creatine kinase and creatine kinase-MB elevation among ferromanganese refinery workers

BACKGROUND

Elevated exposure to manganese (Mn) could induce cardiovascular dysfunction. However, limited research is available on the effects of occupational Mn exposure on myocardial enzymes. We aimed to evaluate the relationships between Mn exposure and myocardial enzyme elevation among Mn-exposed workers.

METHODS

Data were from a follow-up investigation of a Mn-exposed workers healthy cohort in 2017. A total of 744 workers were divided into low-exposure and high-exposure groups according to Mn time-weighted average (Mn-TWA) of less than or equal to 0.15 mg/m³ or greater than 0.15 mg/m³ , respectively. Serum levels of myocardial enzymes, including creatine kinase (CK) and creatine kinase-MB (CK-MB), lactic dehydrogenase, α-hydroxybutyrate dehydrogenase, and aspartate transaminase, were assessed, as well as airborne Mn exposure levels.

RESULTS

After adjustment for sex, body mass index, seniority, education, current smoking status, current drinking status, and hypertension, Mn-TWA levels were positively associated with the risk of CK elevation (odds ratio [OR] = 1.47 (95% confidence interval [CI]: 1.18-1.83) per interquartile range [IQR] increase), and risk of CK-MB elevation [OR = 1.57 (95% CI: 1.03-2.38) per IQR increase]. In a stratified analysis, Mn-TWA levels were positively correlated with CK elevation in workers of seniority greater than 19 years, male workers, current smokers, and drinkers.

CONCLUSION

Our results suggest that occupational exposure to Mn is associated with increased risk of CK and CK-MB elevation. The potential mechanisms of the associations between airborne exposure to Mn and increased risk of these myocardial enzyme elevations warrant further investigation.

The effects of manganese overexposure on brain health

Manganese (Mn) is the twelfth most abundant element on the earth and an essential metal to human health. Mn is present at low concentrations in a variety of dietary sources, which provides adequate Mn content to sustain support various physiological processes in the human body. However, with the rise of Mn utility in a variety of industries, there is an increased risk of overexposure to this transition metal, which can have neurotoxic consequences. This risk includes occupational exposure of Mn to workers as well as overall increased Mn pollution affecting the general public. Here, we review exposure due to air pollution and inhalation in industrial settings; we also delve into the toxic effects of manganese on the brain such as oxidative stress, inflammatory response and transporter dysregulation. Additionally, we summarize current understandings underlying the mechanisms of Mn toxicity.

Blue-collar work and women's health: A systematic review of the evidence from 1990 to 2015

Despite the implications of gender and sex differences for health risks associated with blue-collar work, adverse health outcomes among blue-collar workers has been most frequently studied among men. The present study provides a "state-of-the-field" systematic review of the empiric evidence published on blue-collar women's health. We systematically reviewed literature related to the health of blue-collar women published between January 1, 1990 and December 31, 2015. We limited our review to peer-reviewed studies published in the English language on the health or health behaviors of women who were presently working or had previously worked in a blue-collar job. Studies were eligible for inclusion regardless of the number, age, or geographic region of blue-collar women in the study sample. We retained 177 studies that considered a wide range of health outcomes in study populations from 40 different countries. Overall, these studies suggested inferior health among female blue-collar workers as compared with either blue-collar males or other women. However, we noted several methodological limitations in addition to heterogeneity in study context and design, which inhibited comparison of results across publications. Methodological limitations of the extant literature, alongside the rapidly changing nature of women in the workplace, motivate further study on the health of blue-collar women. Efforts to identify specific mechanisms by which blue-collar work predisposes women to adverse health may be particularly valuable in informing future workplace-based and policy-level interventions.

Follow-up of the manganese-exposed workers healthy cohort (MEWHC) and biobank management from 2011 to 2017 in China

Background

Long-term excess exposure to environmental manganese (Mn) can lead to multi-system damage, especially in occupational populations. Therefore, we established a manganese-exposed workers healthy cohort (MEWHC), focusing on the systemic health effects related to Mn exposure. Here, we aimed to describe the follow-up activity for the MEWHC study and establish a standardized biological sample bank for the scientific management of high-quality biospecimens and the attached data from 2011 to 2017.

Methods

Baseline examinations for onsite workers were conducted, and the biobank for the MEWHC was first established in 2011; follow-up examinations occurred four times between July 2012 and November 2017. All questionnaires, clinical data and biological samples were routinely collected during each follow-up activity. Additional workers were recruited in 2016, which further enriched the resources of the biobank.

Results

A total of 2359 onsite workers and 612 retired workers at a ferromanganese refinery were enrolled in the prospective cohort, and their biological samples were obtained in the preliminary baseline survey and the follow-up investigation, including 2971 blood and urine samples from the cohort. In addition, 1524 hair samples, 1404 nail (toe and finger nails) and 1226 fecal samples were also collected. All specimens were preserved in the biobank, and the data were scientifically managed using a computer system.

Conclusions

The MEWHC study in China provides an effective way to obtain biological samples such as plasma, DNA, hair and urine for storage in a biobank for further study. The standardized management of various samples is crucial for accessing high-quality biospecimens.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5880-0) contains supplementary material, which is available to authorized users.

Excess Manganese-Induced Apoptosis in Chicken Cerebrums and Embryonic Neurocytes

There were many studies about the effect of excess manganese (Mn) on nervous system apoptosis; however, Mn-induced apoptosis in chicken cerebrums and embryonic neurocytes was unclear. The purpose of this study was to investigate the effect of excess Mn on chicken cerebrum and embryonic neurocyte apoptosis. Seven-day-old Hyline male chickens were fed either a commercial diet or three levels of manganese chloride (MnCl₂)-added commercial diets containing 600-, 900-, and 1800-mg/kg-Mn diet, respectively. On the 30th, 60th, and 90th days, cerebrums were collected. Fertilized Hyline chicken eggs were hatched for 6-8 days and were selected. Embryonic neurocytes with 0, 0.5, 1, 1.5, 2, 2.5, and 3 mM Mn were collected and were cultured for 12, 24, 36, and 48 h, respectively. The following research contents were performed: superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) activities; tumor protein p53 (p53), B cell lymphoma-2 (Bcl-2), B cell lymphoma extra large (Bcl-x), Bcl-2-associated X protein (Bax), Bcl-2 homologous antagonist/killer (Bak), fas, and caspase-3 messenger RNA (mRNA) expression; and morphologic observation. The results indicated that excess Mn inhibited SOD and T-AOC activities; induced p53, Bax, Bak, fas, and caspase-3 mRNA expression; and inhibited Bcl-2 and Bcl-x mRNA expression in chicken cerebrums and embryonic neurocytes. There were dose-dependent manners on all the above factors at all the time points and time-dependent manners on SOD activity of 1800-mg/kg-Mn group, T-AOC activity, and apoptosis-related gene mRNA expression in all the treatment groups in chicken cerebrums. Excess Mn induced chicken cerebrum and embryonic neurocyte apoptosis.

Cancer risk of petrochemical workers exposed to airborne PAHs in industrial Lanzhou City, China

This paper reports the connections between red blood cells abnormality risk of petrochemical workers and their exposure to airborne polycyclic aromatic hydrocarbons (PAHs). Urinary 1-hydroxypyrene (1-OHP), as the biomarker of PAHs exposure, was adopted to assess the exposure risk of the petrochemical workers to PAHs in Xigu, the west suburb of Lanzhou where petrochemical industries are located. Fifty-three workers, sub-grouped to 36 petrochemical workers and 17 office workers, participated in this investigation. Logistic regression model and spearman correlation analysis were performed to estimate the associations between PAHs exposure levels and red blood cells abnormality risk of petrochemical workers. Strong associations between some red cell indices (MCH, MCHC, RDW) and 1-OHP concentration were found. Results also show that the red blood cells abnormality risk increased with increasing PAHs exposure level. Compared with office workers, risk level of red blood cells abnormality in petrochemical workers was higher by 41.7 % (OR, 1.417; 95 % CI: 0.368-5.456) than that in office workers. This result was verified by the tissue-to-human blood partition coefficient for pyrene and 1-OHP. The quantitative assessments of the potential health risk through inhalation exposure to PAHs were conducted using the Incremental Lifetime Cancer Risk (ILCR) model. It was found the ILCR from inhalation exposure to PAHs for the petrochemical workers ranged from 10(-5) to 10(-4) with 95 % probability, indicating that petrochemical plant workers were under a high potential cancer risk level.