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Du YJ, Lu ZW, Li KD, Wang YY, Wu H, Huang RG, Jin X, Wang YY, Wang J, Geng AY, Li BZ. No causal association between pneumoconiosis and three inflammatory immune diseases: a Mendelian randomization study. Front Public Health 2024; 12:1373044. [PMID: 38601492 PMCID: PMC11004292 DOI: 10.3389/fpubh.2024.1373044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/14/2024] [Indexed: 04/12/2024] Open
Abstract
Objectives To investigate the causal relationships between pneumoconiosis and rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and gout. Methods The random-effects inverse variance weighted (IVW) approach was utilized to explore the causal effects of the instrumental variables (IVs). Sensitivity analyses using the MR-Egger and weighted median (WM) methods were did to investigate horizontal pleiotropy. A leave-one-out analysis was used to avoid the bias resulting from single-nucleotide polymorphisms (SNPs). Results There was no causal association between pneumoconiosis and SLE, RA or gout in the European population [OR = 1.01, 95% CI: 0.94-1.10, p = 0.74; OR = 1.00, 95% CI: 0.999-1.000, p = 0.50; OR = 1.00, 95% CI: 1.000-1.001, p = 0.55]. Causal relationships were also not found in pneumoconiosis due to asbestos and other mineral fibers and SLE, RA and gout [OR = 1.01, 95% CI: 0.96-1.07, p = 0.66; OR = 1.00, 95% CI: 1.00-1.00, p = 0.68; OR = 1.00, 95% CI: 1.00-1.00, p = 0.20]. Conclusion Our study suggests that pneumoconiosis may have no causal relationship with the three inflammatory immune diseases.
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Affiliation(s)
- Yu-Jie Du
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
| | - Zhang-Wei Lu
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
| | - Kai-Di Li
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
| | - Yi-Yu Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
| | - Hong Wu
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
| | - Rong-Gui Huang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
| | - Xue Jin
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
| | - Yi-Yuan Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
| | - Jing Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
| | - An-Yi Geng
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
| | - Bao-Zhu Li
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immune Diseases, Hefei, China
- Second Affiliated Hospital of Anhui Medical University, Hefei, China
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2
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Wang C, Zeng F, Xu C, Xu Q. Anomalous Enrichment of As and Hg in Underground Coal Dust: A Case from Xishan Coalfield, Shanxi Province, North China. ACS OMEGA 2023; 8:13884-13898. [PMID: 37091386 PMCID: PMC10116509 DOI: 10.1021/acsomega.3c00300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 03/27/2023] [Indexed: 05/03/2023]
Abstract
Coal dust is an important source of coal workers' pneumoconiosis, which is harmful to the health of underground workers. The coal dust samples were directly collected using a coal dust sampler from four major production positions in the underground coal mine. The particle size distribution, mineralogy, and occurrence of As and Hg in the coal dust samples were investigated. The results indicated that the contents of As and Hg were depleted or normal in the parent coal samples compared with the average values of C-P coal in North China and Chinese coal, but they were anomalously enriched in coal dusts. The concentrations of As and Hg in the coal dust samples studied are greater than the values of the elements in the parent coal. The As content in the coal dust samples studied is about one to three orders of magnitude above the parent coal value and the Hg content in the studied coal is 1.28 to 20.28 times higher than the parent coal value. The modes of occurrences of As and Hg were studied by sequential chemical extraction in combination with field emission scanning electron microscopy-energy dispersive spectroscopy (FESEM-EDS) and high-resolution transmission electron microscopy-EDS (HRTEM-EDS). The occurrence of As is dominated mainly by pyrite and secondarily by carbonate and silicate in the coal dust samples. Pyritic Hg and organic Hg may be the dominant forms in mining face and heading face samples, and carbonate and pyritic Hg are the main forms in rocks roadway and return airway samples. It is considered that the mechanochemical effect resulted in the formation of surface active sites and modification of the morphology. Harmful trace elements, such as As, Cd, Hg, Se, Pb, Co, Sb, and Tl, and minor grains associated with nanominerals that bear much hazardous elements, could easily be originally fractionated or adsorbed by airborne particulates. This research aims to provide a theoretical basis for the prevention of occupational disease and underground environmental evaluation.
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Affiliation(s)
- Chuange Wang
- Department
of Earth Science and Engineering, Taiyuan
University of Technology, Taiyuan 030024, China
- Shanxi
Key Laboratory of Coal and Coal-measure Gas Geology, Taiyuan 030024, China
| | - Fangui Zeng
- Department
of Earth Science and Engineering, Taiyuan
University of Technology, Taiyuan 030024, China
- Shanxi
Key Laboratory of Coal and Coal-measure Gas Geology, Taiyuan 030024, China
| | - Chengxiang Xu
- Department
of Earth Science and Engineering, Taiyuan
University of Technology, Taiyuan 030024, China
- Shanxi
Key Laboratory of Coal and Coal-measure Gas Geology, Taiyuan 030024, China
| | - Qiuyue Xu
- Department
of Earth Science and Engineering, Taiyuan
University of Technology, Taiyuan 030024, China
- Shanxi
Key Laboratory of Coal and Coal-measure Gas Geology, Taiyuan 030024, China
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3
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Grytting VS, Refsnes M, Øvrevik J, Halle MS, Schönenberger J, van der Lelij R, Snilsberg B, Skuland T, Blom R, Låg M. Respirable stone particles differ in their ability to induce cytotoxicity and pro-inflammatory responses in cell models of the human airways. Part Fibre Toxicol 2021; 18:18. [PMID: 33957952 PMCID: PMC8101231 DOI: 10.1186/s12989-021-00409-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 04/08/2021] [Indexed: 11/30/2022] Open
Abstract
Background Respirable stone- and mineral particles may be a major constituent in occupational and ambient air pollution and represent a possible health hazard. However, with exception of quartz and asbestos, little is known about the toxic properties of mineral particles. In the present study, the pro-inflammatory and cytotoxic responses to six stone particle samples of different composition and with diameter below 10 μm were assessed in human bronchial epithelial cells (HBEC3-KT), THP-1 macrophages and a HBEC3-KT/THP-1 co-culture. Moreover, particle-induced lysis of human erythrocytes was assessed to determine the ability of the particles to lyse biological membranes. Finally, the role of the NLRP3 inflammasome was assessed using a NLRP3-specific inhibitor and detection of ASC oligomers and cleaved caspase-1 and IL-1β. A reference sample of pure α-quartz was included for comparison. Results Several stone particle samples induced a concentration-dependent increase in cytotoxicity and secretion of the pro-inflammatory cytokines CXCL8, IL-1α, IL-1β and TNFα. In HBEC3-KT, quartzite and anorthosite were the most cytotoxic stone particle samples and induced the highest levels of cytokines. Quartzite and anorthosite were also the most cytotoxic samples in THP-1 macrophages, while anorthosite and hornfels induced the highest cytokine responses. In comparison, few significant differences between particle samples were detected in the co-culture. Adjusting responses for differences in surface area concentrations did not fully account for the differences between particle samples. Moreover, the stone particles had low hemolytic potential, indicating that the effects were not driven by membrane lysis. Pre-incubation with a NLRP3-specific inhibitor reduced stone particle-induced cytokine responses in THP-1 macrophages, but not in HBEC3-KT cells, suggesting that the effects are mediated through different mechanisms in epithelial cells and macrophages. Particle exposure also induced an increase in ASC oligomers and cleaved caspase-1 and IL-1β in THP-1 macrophages, confirming the involvement of the NLRP3 inflammasome. Conclusions The present study indicates that stone particles induce cytotoxicity and pro-inflammatory responses in human bronchial epithelial cells and macrophages, acting through NLRP3-independent and -dependent mechanisms, respectively. Moreover, some particle samples induced cytotoxicity and cytokine release to a similar or greater extent than α-quartz. Thus, these minerals warrant further attention in future research. Supplementary Information The online version contains supplementary material available at 10.1186/s12989-021-00409-y.
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Affiliation(s)
- Vegard Sæter Grytting
- Section of Air Pollution and Noise, Department of Environmental Health, Domain of Infectious Disease Control and Environmental Health, Norwegian Institute of Public Health, PO Box 4404, Nydalen, N-0403, Oslo, Norway.
| | - Magne Refsnes
- Section of Air Pollution and Noise, Department of Environmental Health, Domain of Infectious Disease Control and Environmental Health, Norwegian Institute of Public Health, PO Box 4404, Nydalen, N-0403, Oslo, Norway
| | - Johan Øvrevik
- Section of Air Pollution and Noise, Department of Environmental Health, Domain of Infectious Disease Control and Environmental Health, Norwegian Institute of Public Health, PO Box 4404, Nydalen, N-0403, Oslo, Norway
| | | | | | | | | | - Tonje Skuland
- Section of Air Pollution and Noise, Department of Environmental Health, Domain of Infectious Disease Control and Environmental Health, Norwegian Institute of Public Health, PO Box 4404, Nydalen, N-0403, Oslo, Norway
| | | | - Marit Låg
- Section of Air Pollution and Noise, Department of Environmental Health, Domain of Infectious Disease Control and Environmental Health, Norwegian Institute of Public Health, PO Box 4404, Nydalen, N-0403, Oslo, Norway.
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Occupational Exposures in an Equestrian Centre to Respirable Dust and Respirable Crystalline Silica. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16173226. [PMID: 31484444 PMCID: PMC6747462 DOI: 10.3390/ijerph16173226] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 08/28/2019] [Accepted: 08/31/2019] [Indexed: 11/17/2022]
Abstract
Sand-based products are regularly used as footing material on indoor equestrian arenas, creating a potential occupational exposure risk for respirable crystalline silica (RCS) for equestrian workers training and exercising horses in these environments. The objective of this study was to evaluate an equestrian worker's personal RCS and respirable dust (RD) exposure. Sixteen personal full-shift RD measurements were collected from an equestrian worker and analysed for RD, quartz and cristobalite. Geometric mean exposures of 0.12 mg m-3 and 0.02 mg m-3 were calculated for RD and RCS concentrations, respectively. RCS exposures of between 0.01 to 0.09 mg m-3 were measured on days when the indoor arena surface was not watered, compared to lower exposures (<LOD-0.03 mg m-3) on days when the indoor arena was watered (p < 0.01); however, manual watering is time intensive and less likely to be implemented in practice. This small-scale study provides new data on RCS and RD exposures among equestrian workers. RCS exposures are within the range considered to be associated with increased risk for lung cancer. The use of dust control solutions such as water suppression should be promoted for equestrian work in horse riding arenas. Equestrian workers need to receive occupational health training on the health risks associated with RCS exposure.
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Boyles MSP, Brown D, Knox J, Horobin M, Miller MR, Johnston HJ, Stone V. Assessing the bioactivity of crystalline silica in heated high-temperature insulation wools. Inhal Toxicol 2018; 30:255-272. [PMID: 30328741 PMCID: PMC6334780 DOI: 10.1080/08958378.2018.1513610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
High-Temperature Insulation Wools (HTIW), such as alumino silicate wools (Refractory Ceramic Fibers) and Alkaline Earth Silicate wools, are used in high-temperature industries for thermal insulation. These materials have an amorphous glass-like structure. In some applications, exposure to high temperatures causes devitrification resulting in the formation of crystalline species including crystalline silica. The formation of this potentially carcinogenic material raises safety concerns regarding after-use handling and disposal. This study aims to determine whether cristobalite formed in HTIW is bioactive in vitro. Mouse macrophage (J774A.1) and human alveolar epithelial (A549) cell lines were exposed to pristine HTIW of different compositions, and corresponding heat-treated samples. Cell death, cytokine release, and reactive oxygen species (ROS) formation were assessed in both cell types. Cell responses to aluminum lactate-coated fibers were assessed to determine if responses were caused by crystalline silica. DQ12 α-quartz was used as positive control, and TiO2 as negative control. HTIW did not induce cell death or intracellular ROS, and their ability to induce pro-inflammatory mediator release was low. In contrast, DQ12 induced cytotoxicity, a strong pro-inflammatory response and ROS generation. The modest pro-inflammatory mediator responses of HTIW did not always coincide with the formation of cristobalite in heated fibers; therefore, we cannot confirm that devitrification of HTIW results in bioactive cristobalite in vitro. In conclusion, the biological responses to HTIW observed were not attributable to a single physicochemical characteristic; instead, a combination of physicochemical characteristics (cristobalite content, fiber chemistry, dimensions and material solubility) appear to contribute to induction of cellular responses.
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Affiliation(s)
- Matthew S P Boyles
- a Nano Safety Research Group, School of Engineering and Physical Sciences, Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University , Edinburgh , UK
| | - David Brown
- a Nano Safety Research Group, School of Engineering and Physical Sciences, Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University , Edinburgh , UK
| | - Jilly Knox
- b Morgan Advanced Materials, Thermal Ceramics , Bromborough, UK
| | - Michael Horobin
- b Morgan Advanced Materials, Thermal Ceramics , Bromborough, UK
| | - Mark R Miller
- c Centre for Cardiovascular Science , University of Edinburgh , Edinburgh , UK
| | - Helinor J Johnston
- a Nano Safety Research Group, School of Engineering and Physical Sciences, Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University , Edinburgh , UK
| | - Vicki Stone
- a Nano Safety Research Group, School of Engineering and Physical Sciences, Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University , Edinburgh , UK
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6
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Nattrass C, Horwell CJ, Damby DE, Brown D, Stone V. The effect of aluminium and sodium impurities on the in vitro toxicity and pro-inflammatory potential of cristobalite. ENVIRONMENTAL RESEARCH 2017; 159:164-175. [PMID: 28802207 DOI: 10.1016/j.envres.2017.07.054] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/24/2017] [Accepted: 07/31/2017] [Indexed: 05/26/2023]
Abstract
BACKGROUND Exposure to crystalline silica (SiO2), in the form of quartz, tridymite or cristobalite, can cause respiratory diseases, such as silicosis. However, the observed toxicity and pathogenicity of crystalline silica is highly variable. This has been attributed to a number of inherent and external factors, including the presence of impurities. In cristobalite-rich dusts, substitutions of aluminium (Al) for silicon (Si) in the cristobalite structure, and impurities occluding the silica surface, have been hypothesised to decrease its toxicity. This hypothesis is tested here through the characterisation and in vitro toxicological study of synthesised cristobalite with incremental amounts of Al and sodium (Na) dopants. METHODS Samples of synthetic cristobalite with incremental amounts of Al and Na impurities, and tridymite, were produced through heating of a silica sol-gel. Samples were characterised for mineralogy, cristobalite purity and abundance, particle size, surface area and surface charge. In vitro assays assessed the ability of the samples to induce cytotoxicity and TNF-α production in J774 macrophages, and haemolysis of red blood cells. RESULTS Al-only doped or Al+Na co-doped cristobalite contained between 1 and 4 oxide wt% Al and Na within its structure. Co-doped samples also contained Al- and Na-rich phases, such as albite. Doping reduced cytotoxicity to J774 macrophages and haemolytic capacity compared to non-doped samples. Al-only doping was more effective at decreasing cristobalite reactivity than Al+Na co-doping. The reduction in the reactivity of cristobalite is attributed to both structural impurities and a lower abundance of crystalline silica in doped samples. Neither non-doped nor doped crystalline silica induced production of the pro-inflammatory cytokine TNF-α in J774 macrophages. CONCLUSIONS Impurities can reduce the toxic potential of cristobalite and may help explain the low reactivity of some cristobalite-rich dusts. Whilst further work is required to determine if these effects translate to altered pathogenesis, the results have potential implications for the regulation of crystalline silica exposures.
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Affiliation(s)
- C Nattrass
- Institute of Hazard, Risk & Resilience, Department of Earth Sciences, Durham University, Durham DH1 3LE, UK.
| | - C J Horwell
- Institute of Hazard, Risk & Resilience, Department of Earth Sciences, Durham University, Durham DH1 3LE, UK.
| | - D E Damby
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universitaet Muenchen, Munich 80333, Germany; United States Geological Survey, Menlo Park, California 94025, USA.
| | - D Brown
- School of Life Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.
| | - V Stone
- School of Life Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.
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7
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Pavan C, Fubini B. Unveiling the Variability of “Quartz Hazard” in Light of Recent Toxicological Findings. Chem Res Toxicol 2016; 30:469-485. [DOI: 10.1021/acs.chemrestox.6b00409] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Cristina Pavan
- Department of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy
- “G. Scansetti” Interdepartmental
Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 9, 10125 Turin, Italy
| | - Bice Fubini
- Department of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy
- “G. Scansetti” Interdepartmental
Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 9, 10125 Turin, Italy
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8
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Stone V, Johnston HJ, Balharry D, Gernand JM, Gulumian M. Approaches to Develop Alternative Testing Strategies to Inform Human Health Risk Assessment of Nanomaterials. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2016; 36:1538-1550. [PMID: 27285586 DOI: 10.1111/risa.12645] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 02/11/2016] [Accepted: 04/12/2016] [Indexed: 06/06/2023]
Abstract
The development of alternative testing strategies (ATS) for hazard assessment of new and emerging materials is high on the agenda of scientists, funders, and regulators. The relatively large number of nanomaterials on the market and under development means that an increasing emphasis will be placed on the use of reliable, predictive ATS when assessing their safety. We have provided recommendations as to how ATS development for assessment of nanomaterial hazard may be accelerated. Predefined search terms were used to identify the quantity and distribution of peer-reviewed publications for nanomaterial hazard assessment following inhalation, ingestion, or dermal absorption. A summary of knowledge gaps relating to nanomaterial hazard is provided to identify future research priorities and areas in which a rich data set might exist to allow ATS identification. Consultation with stakeholders (e.g., academia, industry, regulators) was critical to ensure that current expert opinion was reflected. The gap analysis revealed an abundance of studies that assessed the local and systemic impacts of inhaled particles, and so ATS are available for immediate use. Development of ATS for assessment of the dermal toxicity of chemicals is already relatively advanced, and these models should be applied to nanomaterials as relatively few studies have assessed the dermal toxicity of nanomaterials to date. Limited studies have investigated the local and systemic impacts of ingested nanomaterials. If the recommendations for research prioritization proposed are adopted, it is envisioned that a comprehensive battery of ATS can be developed to support the risk assessment process for nanomaterials. Some alternative models are available for immediate implementation, while others require more developmental work to become widely adopted. Case studies are included that can be used to inform the selection of alternative models and end points when assessing the pathogenicity of fibers and mode of action of nanomaterial toxicity.
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Affiliation(s)
- Vicki Stone
- School of Life Sciences, Nano Safety Research Group, Heriot-Watt University, Edinburgh, UK
| | - Helinor J Johnston
- School of Life Sciences, Nano Safety Research Group, Heriot-Watt University, Edinburgh, UK
| | - Dominique Balharry
- School of Life Sciences, Nano Safety Research Group, Heriot-Watt University, Edinburgh, UK
- Centre for Genomic & Experimental Medicine, Institute of Genetics & Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Jeremy M Gernand
- Department of Energy and Mineral Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Mary Gulumian
- Toxicology and Biochemistry Section NIOH, Johannesburg, South Africa
- Haematology and Molecular Medicine Department School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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9
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Turci F, Pavan C, Leinardi R, Tomatis M, Pastero L, Garry D, Anguissola S, Lison D, Fubini B. Revisiting the paradigm of silica pathogenicity with synthetic quartz crystals: the role of crystallinity and surface disorder. Part Fibre Toxicol 2016; 13:32. [PMID: 27286702 PMCID: PMC4902968 DOI: 10.1186/s12989-016-0136-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/05/2016] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Exposure to some - but not all - quartz particles is associated to silicosis, lung cancer and autoimmune diseases. What imparts pathogenicity to any single quartz source is however still unclear. Crystallinity and various surface features are implied in toxicity. Quartz dusts used so far in particle toxicology have been obtained by grinding rocks containing natural quartz, a process which affects crystallinity and yields dusts with variable surface states. To clarify the role of crystallinity in quartz pathogenicity we have grown intact quartz crystals in respirable size. METHODS Quartz crystals were grown and compared with a fractured specimen obtained by grinding the largest synthetic crystals and a mineral quartz (positive control). The key physico-chemical features relevant to particle toxicity - particle size distribution, micromorphology, crystallinity, surface charge, cell-free oxidative potential - were evaluated. Membranolysis was assessed on biological and artificial membranes. Endpoints of cellular stress were evaluated on RAW 264.7 murine macrophages by High Content Analysis after ascertaining cellular uptake by bio-TEM imaging of quartz-exposed cells. RESULTS Quartz crystals were grown in the submicron (n-Qz-syn) or micron (μ-Qz-syn) range by modulating the synthetic procedure. Independently from size as-grown quartz crystals with regular intact faces did not elicit cellular toxicity and lysosomal stress on RAW 264.7 macrophages, and were non-membranolytic on liposome and red blood cells. When fractured, synthetic quartz (μ-Qz-syn-f) attained particle morphology and size close to the mineral quartz dust (Qz-f, positive control) and similarly induced cellular toxicity and membranolysis. Fracturing imparted a higher heterogeneity of silanol acidic sites and radical species at the quartz surface. CONCLUSIONS Our data support the hypothesis that the biological activity of quartz dust is not due to crystallinity but to crystal fragmentation, when conchoidal fractures are formed. Besides radical generation, fracturing upsets the expected long-range order of non-radical surface moieties - silanols, silanolates, siloxanes - which disrupt membranes and induce cellular toxicity, both outcomes associated to the inflammatory response to quartz.
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Affiliation(s)
- Francesco Turci
- Department of Chemistry, University of Torino, Via P. Giuria 7, Turin, 10125, Italy.
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy.
| | - Cristina Pavan
- Department of Chemistry, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
| | - Riccardo Leinardi
- Department of Chemistry, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
| | - Maura Tomatis
- Department of Chemistry, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
| | - Linda Pastero
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
- Department of Earth Sciences, University of Torino, Via V. Caluso 35, Turin, 10125, Italy
| | - David Garry
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin, Dublin, Belfield, Ireland
| | - Sergio Anguissola
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin, Dublin, Belfield, Ireland
| | - Dominique Lison
- Louvain centre for Toxicology and Applied Pharmacology (LTAP), Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, Brussels, 1200, Belgium
| | - Bice Fubini
- Department of Chemistry, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
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10
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Nattrass C, Horwell CJ, Damby DE, Kermanizadeh A, Brown DM, Stone V. The global variability of diatomaceous earth toxicity: a physicochemical and in vitro investigation. J Occup Med Toxicol 2015. [PMID: 26199640 PMCID: PMC4509483 DOI: 10.1186/s12995-015-0064-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background Diatomaceous earth (DE) is mined globally and is potentially of occupational respiratory health concern due to the high crystalline silica content in processed material. DE toxicity, in terms of variability related to global source and processing technique, is poorly understood. This study addresses this variability using physicochemical characterisation and in vitro toxicology assays. Methods Nineteen DE samples sourced from around the world, comprising unprocessed, calcined and flux-calcined DE, were analysed for chemical and mineral composition, particle size and morphology, and surface area. The potential toxicity of DE was assessed by its haemolytic capacity, and its ability to induce cytotoxicity or cytokine release by J774 macrophages. Results The potential toxicity of DE varied with source and processing technique, ranging from non-reactive to as cytotoxic and haemolytic as DQ12. Crystalline silica-rich, flux-calcined samples were all unreactive, regardless of source. The potential toxicity of unprocessed and calcined samples was variable, and did not correlate with crystalline silica content. Calcium-rich phases, iron content, amorphous material, particle size and morphology all appeared to play a role in sample reactivity. An increased surface area was linked to an increased reactivity in vitro for some sample types. Conclusions Overall, no single property of DE could be linked to its potential toxicity, but crystalline silica content was not a dominant factor. Occlusion of the potentially toxic crystalline silica surface by an amorphous matrix or other minerals and impurities in the crystal structure are suggested to pacify toxicity in these samples. In vivo verification is required, but these data suggest that crystalline silica content alone is not a sufficient indicator of the potential DE hazard. Electronic supplementary material The online version of this article (doi:10.1186/s12995-015-0064-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- C Nattrass
- Institute of Hazard, Risk & Resilience, Department of Earth Sciences, Durham University, Durham, DH1 3LE UK
| | - C J Horwell
- Institute of Hazard, Risk & Resilience, Department of Earth Sciences, Durham University, Durham, DH1 3LE UK
| | - D E Damby
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Munich, 80333 Germany
| | - A Kermanizadeh
- School of Life Sciences, Heriot-Watt University, Edinburgh, EH14 4AS UK ; Department of Public Health, Section of Occupational and Environmental Health, University of Copenhagen, Copenhagen, DK-1014 Denmark
| | - D M Brown
- School of Life Sciences, Heriot-Watt University, Edinburgh, EH14 4AS UK
| | - V Stone
- School of Life Sciences, Heriot-Watt University, Edinburgh, EH14 4AS UK
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11
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Damby DE, Llewellin EW, Horwell CJ, Williamson BJ, Najorka J, Cressey G, Carpenter M. The α-β phase transition in volcanic cristobalite. J Appl Crystallogr 2014; 47:1205-1215. [PMID: 25242910 PMCID: PMC4119948 DOI: 10.1107/s160057671401070x] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 05/09/2014] [Indexed: 01/21/2023] Open
Abstract
Cristobalite is a common mineral in volcanic ash produced from dome-forming eruptions. Assessment of the respiratory hazard posed by volcanic ash requires understanding the nature of the cristobalite it contains. Volcanic cristobalite contains coupled substitutions of Al3+ and Na+ for Si4+; similar co-substitutions in synthetic cristobalite are known to modify the crystal structure, affecting the stability of the α and β forms and the observed transition between them. Here, for the first time, the dynamics and energy changes associated with the α-β phase transition in volcanic cristobalite are investigated using X-ray powder diffraction with simultaneous in situ heating and differential scanning calorimetry. At ambient temperature, volcanic cristobalite exists in the α form and has a larger cell volume than synthetic α-cristobalite; as a result, its diffraction pattern sits between ICDD α- and β-cristobalite library patterns, which could cause ambiguity in phase identification. On heating from ambient temperature, volcanic cristobalite exhibits a lower degree of thermal expansion than synthetic cristobalite, and it also has a lower α-β transition temperature (∼473 K) compared with synthetic cristobalite (upwards of 543 K); these observations are discussed in relation to the presence of Al3+ and Na+ defects. The transition shows a stable and reproducible hysteresis loop with α and β phases coexisting through the transition, suggesting that discrete crystals in the sample have different transition temperatures.
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Affiliation(s)
- David E. Damby
- Department of Earth Sciences, Durham University, South Road, Durham DH1 3LE, UK
- Institute of Hazard, Risk and Resilience, Durham University, South Road, Durham DH1 3LE, UK
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Munich 80333, Germany
| | - Edward W. Llewellin
- Department of Earth Sciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Claire J. Horwell
- Department of Earth Sciences, Durham University, South Road, Durham DH1 3LE, UK
- Institute of Hazard, Risk and Resilience, Durham University, South Road, Durham DH1 3LE, UK
| | - Ben J. Williamson
- Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Penryn TR10 9EZ, UK
| | - Jens Najorka
- Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Gordon Cressey
- Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Michael Carpenter
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
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12
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Horwell CJ, Williamson BJ, Donaldson K, Le Blond JS, Damby DE, Bowen L. The structure of volcanic cristobalite in relation to its toxicity; relevance for the variable crystalline silica hazard. Part Fibre Toxicol 2012; 9:44. [PMID: 23164071 PMCID: PMC3574026 DOI: 10.1186/1743-8977-9-44] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 10/31/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Respirable crystalline silica (RCS) continues to pose a risk to human health worldwide. Its variable toxicity depends on inherent characteristics and external factors which influence surface chemistry. Significant population exposure to RCS occurs during volcanic eruptions, where ashfall may cover hundreds of square km and exposure may last years. Occupational exposure also occurs through mining of volcanic deposits. The primary source of RCS from volcanoes is through collapse and fragmentation of lava domes within which cristobalite is mass produced. After 30 years of research, it is still not clear if volcanic ash is a chronic respiratory health hazard. Toxicological assays have shown that cristobalite-rich ash is less toxic than expected. We investigate the reasons for this by determining the physicochemical/structural characteristics which may modify the pathogenicity of volcanic RCS. Four theories are considered: 1) the reactivity of particle surfaces is reduced due to co-substitutions of Al and Na for Si in the cristobalite structure; 2) particles consist of aggregates of cristobalite and other phases, restricting the surface area of cristobalite available for reactions in the lung; 3) the cristobalite surface is occluded by an annealed rim; 4) dissolution of other volcanic particles affects the surfaces of RCS in the lung. METHODS The composition of volcanic cristobalite crystals was quantified by electron microprobe and differences in composition assessed by Welch's two sample t-test. Sections of dome-rock and ash particles were imaged by scanning and transmission electron microscopy, and elemental compositions of rims determined by energy dispersive X-ray spectroscopy. RESULTS Volcanic cristobalite contains up to 4 wt. % combined Al(2)O(3) and Na(2)O. Most cristobalite-bearing ash particles contain adhered materials such as feldspar and glass. No annealed rims were observed. CONCLUSIONS The composition of volcanic cristobalite particles gives insight into previously-unconsidered inherent characteristics of silica mineralogy which may affect toxicity. The structural features identified may also influence the hazard of other environmentally and occupationally produced silica dusts. Current exposure regulations do not take into account the characteristics that might render the silica surface less harmful. Further research would facilitate refinement of the existing simple, mass-based silica standard by taking into account composition, allowing higher standards to be set in industries where the silica surface is modified.
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Affiliation(s)
- Claire J Horwell
- Institute of Hazard, Risk & Resilience, Department of Earth Sciences, Durham University, Science Labs., South Road, Durham, DH1 3LE, UK
| | - Benedict J Williamson
- Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Cornwall Campus, Penryn, TR10 9EZ, UK
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Ken Donaldson
- The Queen's Medical Research Institute, The University of Edinburgh/MRC Centre for Inflammation Research, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Jennifer S Le Blond
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
- Brighton and Sussex Medical School, University of Sussex, Brighton, East Sussex, BN1 9PX, UK
| | - David E Damby
- Institute of Hazard, Risk & Resilience, Department of Earth Sciences, Durham University, Science Labs., South Road, Durham, DH1 3LE, UK
| | - Leon Bowen
- Durham GJ Russell Microscopy Facility, Durham University, Durham, DH1 3LE, UK
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13
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Geh S, Yücel R, Duffin R, Albrecht C, Borm PJA, Armbruster L, Raulf-Heimsoth M, Brüning T, Hoffmann E, Rettenmeier AW, Dopp E. Cellular uptake and cytotoxic potential of respirable bentonite particles with different quartz contents and chemical modifications in human lung fibroblasts. Arch Toxicol 2005; 80:98-106. [PMID: 16059726 DOI: 10.1007/s00204-005-0013-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Accepted: 07/06/2005] [Indexed: 10/25/2022]
Abstract
Considering the biological reactivity of pure quartz in lung cells, there is a strong interest to clarify the cellular effects of respirable siliceous dusts, like bentonites. In the present study, we investigated the cellular uptake and the cytotoxic potential of bentonite particles (Ø< 10 microm) with an alpha-quartz content of up to 6% and different chemical modifications (activation: alkaline, acidic, organic) in human lung fibroblasts (IMR90). Additionally, the ability of the particles to induce apoptosis in IMR90-cells and the hemolytic activity was tested. All bentonite samples were tested for endotoxins with the in vitro-Pyrogen test and were found to be negative. Cellular uptake of particles by IMR90-cells was studied by transmission electron microscopy (TEM). Cytotoxicity was analyzed in IMR90-cells by determination of viable cells using flow cytometry and by measuring of the cell respiratory activity. Induced apoptotic cells were detected by AnnexinV/Propidiumiodide-staining and gel electrophoresis. Our results demonstrate that activated bentonite particles are better taken up by IMR90-cells than untreated (native) bentonite particles. Also, activated bentonite particles with a quartz content of 5-6% were more cytotoxic than untreated bentonites or bentonites with a quartz content lower than 4%. The bentonite samples induced necrotic as well as apoptotic cell death. In general, bentonites showed a high membrane-damaging potential shown as hemolytic activity in human erythrocytes. We conclude that cellular effects of bentonite particles in human lung cells are enhanced after chemical treatment of the particles. The cytotoxic potential of the different bentonites is primarily characterized by a strong lysis of the cell membrane.
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Affiliation(s)
- Stefan Geh
- Institute of Hygiene and Occupational Medicine, University Hospital, Hufelandstrasse 55, 45122 Essen, Germany
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