Suchergebnisse

Abstract
Production and application of multi-component nanomaterials (MCNMs) and high aspect ratio nanomaterials (HARN) has raised questions as to their inhalation risk. A PRISMA-orientated systematic literature review indicated a key knowledge gap related to the (geno)toxicity of metal oxide MCNMs and HARN. The aim of this study was to conduct a mechanistic-based toxicology assessment of a number of industrially-relevant MCNMs and HARN materials, in order to fill this knowledge gap and provide vital hazard assessment towards these materials' safe and sustainable design. A549 monocultures (2.5x105), and A549/dTHP-1 co-cultures (1:10) were seeded in 12-well transwell-membranes at the air-liquid interface. Cell cultures were exposed, via aerosol, to Printex90, LaCo0.5Ni0.05O3, LaCo0.475Ni0.475Pt0.05O3, LaCo0.475Ni0.475Pd0.05O3, LaCo0.25Ni0.75O3, LaNiO3, NiZnFe4O8, ZnFe2O4, and NiFe2O4 to human exposure-relevant concentrations of 390, 780, 3100 ng/cm2 (24hrs). Aerosolised MCNM and HARN were characterised following acellular deposition via electron microscopy. Cellular cytotoxicity, barrier integrity, (pro)inflammatory/fibrotic response, oxidative stress and mutagenicity/DNA damage was assessed. Results indicate barrier integrity and IL-8 production were unaffected by Printex90, LaCo0.5Ni0.05O3, and ZnFe2O4 exposure. A dose-dependent increase in micronucleus frequency was observed for these four materials. Investigations are continuing to determine the mechanisms associated with this noted genotoxic effect, as well as upon further MCNMs/HARN (i.e. Fe2CoO4(Fe1/Co3), Silica-Ref-Std). Emphasis is being placed upon elucidating specific structure-activity relationships for each MCNM/HARN by testing specific key events of inhalation-based adverse outcome pathways relevant to the in vitro models used. This project was funded by EU H2020 research and innovation programme, grant agreement No. 953183 (HARMLESS).

Abstract
Particle inhalation is linked to diseases including cancer, COPD, fibrosis and cardiovascular disease. We propose a biological mechanism-of-action for particle-induced cardiovascular disease causally linking particle exposure to induction of acute phase response, which in turn is a known risk factor for atherosclerosis and cardiovascular disease. Inhalation and pulmonary deposition of particles induce inflammation, which is proportional to the total surface area of the pulmonary-deposited particles. In mice, inflammation is accompanied by an acute phase response, which is long-lasting for insoluble particles. Acute phase protein Serum Amyloid A (SAA) is among the most differentially expressed genes in lung tissue following particle exposure. SAA is causally implicated in atherosclerosis and both overexpression and pulmonary dosing of SAA promote plaque formation in ApoE-/- mice. In mice, we show that both soluble and insoluble metal fume particles induce acute phase response but with different time-dependence. Neutrophil influx, pulmonary Saa expression and SAA blood levels are highly correlated in mice and may be used as biomarkers of each other. In humans, controlled exposure to metal oxides and combustion particles induces dose-dependent increases in blood levels of SAA and C-reactive protein. Blood levels of acute phase proteins SAA and C-reactive protein are risk factors for cardiovascular disease in prospective, epidemiological studies. Nanoparticles have a higher specific surface area than larger particles with similar chemical composition, and consequently, nanoparticles are more hazardous than larger particles of similar chemical composition in relation to cardiovascular disease. This underscores cardiovascular disease as a particle-induced occupational disease.

Abstract
The difficulty of nanomaterial (NM) grouping can be simplified if the most toxicologically relevant dose metric is used to assess the toxicological dose-response. Retained surface area could be useful for this purpose. Here, we thoroughly investigated the relationship between acute and chronic inflammation (based on polymorphonuclear neutrophil influx (% PMN) in lung bronchoalveolar lavage) and the retained surface area in the lung. 4-week inhalation studies were performed in rats with three benchmark materials: the TiO2 P25 and the carbon black Printex-90 as poorly soluble particles of low toxicity (PSLT), and the multiwall carbon nanotube (MWCNT) MWNT-7. We compared our results to published data from nearly 30 rigorously selected articles relating to acute (1-week) to subchronic (13-week) inhalation exposure to the classes of NMs considered. Short and long post-exposure recovery times (immediately after exposure up to more than 6 months) allowed us to examine both acute and chronic inflammation. A dose-response relationship across short-term and long-term studies was revealed linking pulmonary retained surface area dose (measured or estimated) and % PMN. This relationship, taking the form of sigmoid curves, is dependent on the class of NM considered and sometimes on the duration of exposure but is independent of the post-exposure time. Based on retained surface area, long and thick MWCNTs (few hundred nm long with an aspect ratio greater than 25) had a higher inflammatory potency with 4 cm²/g lung sufficient to trigger an inflammatory response (at 6% PMN), whereas retained surfaces greater than 150 cm²/g lung were required for PSLT.

Abstract
Surgical face masks are routinely used in clinical settings, but also extensively by the public during the SARS-CoV-2 pandemic. These masks contain a high proportion of plastic, specifically polypropylene (PP), which could shed microscopic particles to the environment or nasal cavity. However, to-date, despite focus upon an increased environmental burden, the (human) hazard relevant to inhaled MNPs remains largely unknown. The aim of this project therefore, was to determine the toxicity of inhaled PP (commercially available powders, or extracted from surgical masks; either (i) all layers, or (ii) the innermost layer only), using an advanced in vitro approach. Type-II lung epithelial cells (NCI-H441) were cultured at the air-liquid interface and exposed to respirable PP via aerosol for 24hrs at depositions of 500, 100 and 2000 ng/cm2 (Vitrocell Cloud12). Carbon black (Printex 90) was used as a positive particle control. Respirable MNP samples required cryomilling and cryotome slicing, and were analysed using pyrolysis-GCMS. In addition to acellular deposition, as well as particle and cellular morphology (electron microscopy) assessed endpoints of cytotoxicity (trypan blue exclusion), barrier integrity (dextran blue), (pro-)inflammatory response (IL-1β/IL-6/IL-8), oxidative stress (SOD-1), and genotoxicity (mononucleate micronucleus) were conducted. So far, a concentration-dependent decrease in cell viability was observed following exposure to commercial PP and complete mask PP samples, whilst a concentration-dependent increase in all (pro-)inflammatory mediators assessed was noted. Further, initial genotoxicity assessment suggests a minor increase to micronucleus formation for both exposure samples. Preliminary data therefore suggests that aerosolised MNPs instigate a hazardous response in vitro.

Air force ground crew personnel are potentially exposed to fuels and lubricants, as raw materials, vapours and combustion exhaust emissions, during operation and maintenance of aircrafts. This study investigated exposure levels and biomarkers of effects for employees at a Danish air force military base. We enrolled self-reported healthy and non-smoking employees (n = 79) and grouped them by exposure based on job function, considered to be potentially exposed (aircraft engineers, crew chiefs, fuel operators and munition specialists) or as reference group with minimal occupational exposure (avionics and office workers). We measured exposure levels to polycyclic aromatic hydrocarbons (PAHs) and organophosphate esters (OPEs) by silicone bands and skin wipes (PAHs only) as well as urinary excretion of PAH metabolites (OH-PAHs). Additionally, we assessed exposure levels of ultrafine particles (UFPs) in the breathing zone for specific job functions. As biomarkers of effect, we assessed lung function, plasma levels of acute phase inflammatory markers, and genetic damage levels in peripheral blood cells. Exposure levels of total PAHs, OPEs and OH-PAHs did not differ between exposure groups or job functions, with low correlations between PAHs in different matrices. Among the measured job functions, the UFP levels were higher for the crew chiefs. The exposure level of the PAH fluorene was significantly higher for the exposed group than the reference group (15.9 +/- 23.7 ng/g per 24 h vs 5.28 +/- 7.87 ng/g per 24 h, p = 0.007), as was the OPE triphenyl phosphate (305 +/- 606 vs 19.7 +/- 33.8 ng/g per 24 h, p = 0.011). The OPE tris(1,3-dichlor-2-propyl)phosphate had a higher mean in the exposed group (60.7 +/- 135 ng/g per 24 h) compared to the reference group (8.89 +/- 15.7 ng/g per 24 h) but did not reach significance. No evidence of effects for biomarkers of systemic inflammation, genetic damage or lung function was found. Overall, our biomonitoring study show limited evidence of occupational exposure of air force ground crew personnel to UFPs, PAHs and OPEs. Furthermore, the OH-PAHs and the assessed biomarkers of early biological effects did not differ between exposed and reference groups.

Air force ground crew personnel are potentially exposed to fuels and lubricants, as raw materials, vapours and combustion exhaust emissions, during operation and maintenance of aircrafts. This study investigated exposure levels and biomarkers of effects for employees at a Danish air force military base. We enrolled self-reported healthy and non-smoking employees (n = 79) and grouped them by exposure based on job function, considered to be potentially exposed (aircraft engineers, crew chiefs, fuel operators and munition specialists) or as reference group with minimal occupational exposure (avionics and office workers). We measured exposure levels to polycyclic aromatic hydrocarbons (PAHs) and organophosphate esters (OPEs) by silicone bands and skin wipes (PAHs only) as well as urinary excretion of PAH metabolites (OH-PAHs). Additionally, we assessed exposure levels of ultrafine particles (UFPs) in the breathing zone for specific job functions. As biomarkers of effect, we assessed lung function, plasma levels of acute phase inflammatory markers, and genetic damage levels in peripheral blood cells. Exposure levels of total PAHs, OPEs and OH-PAHs did not differ between exposure groups or job functions, with low correlations between PAHs in different matrices. Among the measured job functions, the UFP levels were higher for the crew chiefs. The exposure level of the PAH fluorene was significantly higher for the exposed group than the reference group (15.9 ± 23.7 ng/g per 24 h vs 5.28 ± 7.87 ng/g per 24 h, p = 0.007), as was the OPE triphenyl phosphate (305 ± 606 vs 19.7 ± 33.8 ng/g per 24 h, p = 0.011). The OPE tris(1,3-dichlor-2-propyl)phosphate had a higher mean in the exposed group (60.7 ± 135 ng/g per 24 h) compared to the reference group (8.89 ± 15.7 ng/g per 24 h) but did not reach significance. No evidence of effects for biomarkers of systemic inflammation, genetic damage or lung function was found. Overall, our biomonitoring study show limited evidence of occupational exposure of air force ground crew ...

Air force ground crew personnel are potentially exposed to fuels and lubricants, as raw materials, vapours and combustion exhaust emissions, during operation and maintenance of aircrafts. This study investigated exposure levels and biomarkers of effects for employees at a Danish air force military base. We enrolled self-reported healthy and non-smoking employees (n = 79) and grouped them by exposure based on job function, considered to be potentially exposed (aircraft engineers, crew chiefs, fuel operators and munition specialists) or as reference group with minimal occupational exposure (avionics and office workers). We measured exposure levels to polycyclic aromatic hydrocarbons (PAHs) and organophosphate esters (OPEs) by silicone bands and skin wipes (PAHs only) as well as urinary excretion of PAH metabolites (OH-PAHs). Additionally, we assessed exposure levels of ultrafine particles (UFPs) in the breathing zone for specific job functions. As biomarkers of effect, we assessed lung function, plasma levels of acute phase inflammatory markers, and genetic damage levels in peripheral blood cells. Exposure levels of total PAHs, OPEs and OH-PAHs did not differ between exposure groups or job functions, with low correlations between PAHs in different matrices. Among the measured job functions, the UFP levels were higher for the crew chiefs. The exposure level of the PAH fluorene was significantly higher for the exposed group than the reference group (15.9 ± 23.7 ng/g per 24 h vs 5.28 ± 7.87 ng/g per 24 h, p = 0.007), as was the OPE triphenyl phosphate (305 ± 606 vs 19.7 ± 33.8 ng/g per 24 h, p = 0.011). The OPE tris(1,3-dichlor-2-propyl)phosphate had a higher mean in the exposed group (60.7 ± 135 ng/g per 24 h) compared to the reference group (8.89 ± 15.7 ng/g per 24 h) but did not reach significance. No evidence of effects for biomarkers of systemic inflammation, genetic damage or lung function was found. Overall, our biomonitoring study show limited evidence of occupational exposure of air force ground crew personnel to UFPs, PAHs and OPEs. Furthermore, the OH-PAHs and the assessed biomarkers of early biological effects did not differ between exposed and reference groups.