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Madl AK, Donnell MT, Covell LT. Synthetic vitreous fibers (SVFs): adverse outcome pathways (AOPs) and considerations for next generation new approach methods (NAMs). Crit Rev Toxicol 2024:1-51. [PMID: 39287182 DOI: 10.1080/10408444.2024.2390020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 09/19/2024]
Abstract
Fiber dimension, durability/dissolution, and biopersistence are critical factors for the risk of fibrogenesis and carcinogenesis. In the modern era, to reduce, refine, and replace animals in toxicology research, the application of in vitro test methods is paramount for hazard evaluation and designing synthetic vitreous fibers (SVFs) for safe use. The objectives of this review are to: (1) summarize the international frameworks and acceptability criteria for implementation of new approach methods (NAMs), (2) evaluate the adverse outcome pathways (AOPs), key events (KEs), and key event relationships (KERs) for fiber-induced fibrogenesis and carcinogenesis in accordance with Organization for Economic Co-operation and Development (OECD) guidelines, (3) consider existing and emerging technologies for in silico and in vitro toxicity testing for the respiratory system and the ability to predict effects in vivo, (4) outline a recommended testing strategy for evaluating the hazard and safety of novel SVFs, and (5) reflect on methods needs for in vitro in vivo correlation (IVIVC) and predictive approaches for safety assessment of new SVFs. AOP frameworks following the conceptual model of the OECD were developed through an evaluation of available molecular and cellular initiating events, which lead to KEs and KERs in the development of fiber-induced fibrogenesis and carcinogenesis. AOP framework development included consideration of fiber physicochemical properties, respiratory deposition and clearance patterns, biosolubility, and biopersistence, as well as cellular, organ, and organism responses. Available data support that fiber AOPs begin with fiber physicochemical characteristics which influence fiber exposure and biosolubility and subsequent key initiating events are dependent on fiber biopersistence and reactivity. Key cellular events of pathogenic fibers include oxidative stress, chronic inflammation, and epithelial/fibroblast proliferation and differentiation, which ultimately lead to hyperplasia, metaplasia, and fibrosis/tumor formation. Available in vitro models (e.g. single-, multi-cellular, organ system) provide promising NAMs tools to evaluate these intermediate KEs. However, data on SVFs demonstrate that in vitro biosolubility is a reasonable predictor for downstream events of in vivo biopersistence and biological effects. In vitro SVF fiber dissolution rates >100 ng/cm2/hr (glass fibers in pH 7 and stone fibers in pH 4.5) and in vivo SVF fiber clearance half-life less than 40 or 50 days were not associated with fibrosis or tumors in animals. Long (fiber lengths >20 µm) biodurable and biopersistent fibers exceeding these fiber dissolution and clearance thresholds may pose a risk of fibrosis and cancer. In vitro fiber dissolution assays provide a promising avenue and potentially powerful tool to predict in vivo SVF fiber biopersistence, hazard, and health risk. NAMs for fibers (including SVFs) may involve a multi-factor in vitro approach leveraging in vitro dissolution data in complement with cellular- and tissue- based in vitro assays to predict health risk.
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Affiliation(s)
- Amy K Madl
- Valeo Sciences LLC, Ladera Ranch, CA, USA
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Prueitt RL, Drury NL, Shore RA, Boon DN, Goodman JE. Talc and human cancer: a systematic review of the experimental animal and mechanistic evidence. Crit Rev Toxicol 2024; 54:359-393. [PMID: 38979679 DOI: 10.1080/10408444.2024.2349668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 04/25/2024] [Indexed: 07/10/2024]
Abstract
The potential carcinogenicity of talc has been evaluated in many studies in humans and experimental animals published in the scientific literature over the last several decades, with a number of these studies reporting no associations between talc exposure and any type of cancer. In order to fully understand the current state of the science regarding the potential for talc to induce human cancers, we conducted a comprehensive and systematic review of the available experimental animal and mechanistic evidence (in conjunction with a systematic review of the epidemiology evidence in a companion analysis) to evaluate whether it supports talc as being carcinogenic to humans. We considered study quality and its impact on the interpretation of results and evaluated all types of cancer and all exposure routes. We also evaluated the evidence on the potential for talc to migrate in the body to potential tumor sites. We identified seven experimental animal carcinogenicity studies and 11 mechanistic studies of talc to systematically review. We found that several of the experimental animal carcinogenicity studies of talc have limitations that preclude their sensitivity to detect increases in tumor incidence. Regardless, the studies cover multiple exposure routes, species, and exposure durations, and none indicate that talc is a carcinogen in experimental animals except in rats under conditions of extremely high exposure that likely resulted in lung particle overload, a nonspecific effect of high exposures to poorly soluble particles, and not from any carcinogenic properties of talc. Lung particle overload leading to lung tumor formation has only been observed in rats and not in any other species, including humans. The mechanistic studies indicate that talc is not genotoxic or mutagenic, but can induce some effects that could be events on a possible pathway to carcinogenicity, mainly at high exposures or in in vitro studies with exposures of unclear relevance in vivo, but these effects are not consistent across studies and cell types. This systematic review of the experimental animal carcinogenicity and mechanistic evidence for talc indicates that an association between talc exposure and cancer is not expected in humans. Talc carcinogenicity is not plausible in any species except rats, and only when the exposure conditions are high enough to induce lung particle overload, which is not relevant to human exposures.
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Boreiko CJ. Modeling of local and systemic exposure to metals and metalloids after inhalation exposure: Recommended update to the USEPA metals framework. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2024; 20:952-964. [PMID: 38084064 DOI: 10.1002/ieam.4880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 12/29/2023]
Abstract
The USEPA issued the "Framework for Metal Risk Assessment" in 2007, recognizing that human and environmental exposure to metals and metalloids (MMEs) poses challenges risk assessment. Inhalation of aerosols containing MMEs is a primary pathway for exposure in the occupational setting, for consumer exposure, and to general population exposure associated with point-source emissions or ambient sources. The impacts of inhalation can be at the point of deposition (local exposure) or may manifest after uptake into the body (systemic exposure). Both local and systemic exposure can vary with factors that determine the regional deposition of MME-containing aerosols. Aerosol characteristics such as particle size combine with species-specific characteristics of airway morphology and lung function to modulate the deposition and clearance of MME particulates. In contrast to oral exposure, often monitored by measuring MME levels in blood or urine, inhalation exposure can produce local pulmonary impacts in the absence of significant systemic distribution. Exposure assessment for nutritionally essential MMEs can be further complicated by homeostatic controls that regulate systemic MME levels. Predictions of local exposure can be facilitated by computer models that estimate regional patterns of aerosol deposition, permitting calculation of exposure intensity in different regions of the respiratory tract. The utility of deposition modeling has been demonstrated in assessments of nutritionally essential MMEs regulated by homeostatic controls and in the comparison of results from inhalation studies in experimental animals. This facilitates extrapolation from animal data to humans and comparisons of exposures possessing mechanistic linkages to pulmonary toxicity and carcinogenesis. Pulmonary deposition models have significantly advanced and have been applied by USEPA in evaluations of particulate matter. However, regional deposition modeling has yet to be incorporated into the general guidance offered by the agency for evaluating inhalation exposure. Integr Environ Assess Manag 2024;20:952-964. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Stucki AO, Sauer UG, Allen DG, Kleinstreuer NC, Perron MM, Yozzo KL, Lowit AB, Clippinger AJ. Differences in the anatomy and physiology of the human and rat respiratory tracts and impact on toxicological assessments. Regul Toxicol Pharmacol 2024; 150:105648. [PMID: 38772524 PMCID: PMC11198871 DOI: 10.1016/j.yrtph.2024.105648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/15/2024] [Accepted: 05/18/2024] [Indexed: 05/23/2024]
Abstract
Inhalation is a critical route through which substances can exert adverse effects in humans; therefore, it is important to characterize the potential effects that inhaled substances may have on the human respiratory tract by using fit for purpose, reliable, and human relevant testing tools. In regulatory toxicology testing, rats have primarily been used to assess the effects of inhaled substances as they-being mammals-share similarities in structure and function of the respiratory tract with humans. However, questions about inter-species differences impacting the predictability of human effects have surfaced. Disparities in macroscopic anatomy, microscopic anatomy, or physiology, such as breathing mode (e.g., nose-only versus oronasal breathing), airway structure (e.g., complexity of the nasal turbinates), cell types and location within the respiratory tract, and local metabolism may impact inhalation toxicity testing results. This review shows that these key differences describe uncertainty in the use of rat data to predict human effects and supports an opportunity to harness modern toxicology tools and a detailed understanding of the human respiratory tract to develop testing approaches grounded in human biology. Ultimately, as the regulatory purpose is protecting human health, there is a need for testing approaches based on human biology and mechanisms of toxicity.
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Affiliation(s)
| | - Ursula G Sauer
- Scientific Consultancy - Animal Welfare, Neubiberg, Germany
| | - David G Allen
- International Collaboration on Cosmetics Safety (ICCS), Mount Royal, NJ, USA
| | - Nicole C Kleinstreuer
- National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM), National Institute of Environmental Health Sciences, NC, USA
| | - Monique M Perron
- US Environmental Protection Agency, Office of Pesticide Programs, Washington, DC, USA
| | - Krystle L Yozzo
- US Environmental Protection Agency, Office of Pesticide Programs, Washington, DC, USA
| | - Anna B Lowit
- US Environmental Protection Agency, Office of Pollution Prevention and Toxics, Washington, DC, USA
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5
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Yong M, McCunney RJ. Evaluation of biological markers for the risk assessment of carbon black in epidemiological studies. Front Public Health 2024; 12:1367797. [PMID: 38689765 PMCID: PMC11060078 DOI: 10.3389/fpubh.2024.1367797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 02/13/2024] [Indexed: 05/02/2024] Open
Abstract
Background/objectives Engineered nanomaterials (ENMs) have been suggested as being capable of promoting inflammation, a key component in the pathways associated with carcinogenesis, cardiovascular disease, and other conditions. As a result, the risk assessment of biological markers as early-stage indicators has the potential to improve translation from experimental toxicologic findings to identifying evidence in human studies. The study aims to review the possible early biological changes in workers exposed to carbon black (CB), followed by an evidentiary quality evaluation to determine the predictive value of the biological markers. Methods We conducted a literature search to identify epidemiological studies that assessed biological markers that were involved in the inflammatory process at early stages among workers with exposure to CB. We reviewed the studies with specific reference to the study design, statistical analyses, findings, and limitations. Results We identified five Chinese studies that investigated the potential impact of exposure to CB on inflammatory markers, bronchial wall thickening, genomic instability, and lung function impairment in CB production workers. Of the five Chinese studies, four were cross-sectional; another study reported results at two-time points over six years of follow-up. The authors of all five studies concluded positive relationships between exposure and the inflammatory cytokine profiles. The weak to very weak correlations between biomarkers and early-stage endpoints were reported. Conclusion Most inflammatory markers failed to satisfy the proposed evidentiary quality criteria. The significance of the results of the reviewed studies is limited by the cross-sectional study design, inconsistency in results, uncertain clinical relevance, and high occupational exposures. Based on this review, the risk assessment relying on inflammatory markers does not seem appropriate at this time. Nevertheless, the novel research warrants further exploration in assessing exposure to ENMs and corresponding potential health risks in occupational settings.
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Affiliation(s)
- Mei Yong
- MY EpiConsulting, Duesseldorf, Germany
| | - Robert J. McCunney
- Brigham and Women’s Hospital, Pulmonary Division, Harvard Medical School, Boston, MA, United States
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Vermeire TG, Hoet P, Ion RM, Krätke R, Proykova A, Scott M, de Jong WH. Opinion of the Scientific Committee on health, environmental and emerging risks on the safety of titanium dioxide in toys. Regul Toxicol Pharmacol 2024; 146:105527. [PMID: 38056706 DOI: 10.1016/j.yrtph.2023.105527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/06/2023] [Accepted: 11/16/2023] [Indexed: 12/08/2023]
Abstract
The Opinion of the Scientific Committee on Health, Environmental and Emerging Risks advises the European Commission on whether the uses of titanium dioxide in toys and toy materials can be considered to be safe in light of the identified exposure, and the classification of titanium dioxide as carcinogenic category 2 after inhalation. Four toy products including casting kits, chalk, powder paints and white colour pencils containing various amounts of TiO2 as colouring agent were evaluated for inhalation risks. For the oral route, childrens' lip gloss/lipstick, finger paint and white colour pencils were evaluated. When it can be demonstrated with high certainty that no ultrafine fraction is present in pigmentary TiO2 preparations used in toys and toy materials, safe use with no or negligible risk for all products considered is indicated based on the exposure estimations of this Opinion. However, if an ultrafine fraction is assumed to be present, safe use is not indicated, except for white colour pencils.
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Affiliation(s)
- Theo G Vermeire
- National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | - Peter Hoet
- Katholieke Universiteit Leuven, Leuven, Belgium
| | - Rodica-Mariana Ion
- National Institute of R&D for Chemistry and Petrochemistry - ICECHIM, Bucharest, Romania
| | - Renate Krätke
- Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | | | | | - Wim H de Jong
- National Institute for Public Health (RIVM), Bilthoven, the Netherlands
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Hoffman E, Urbano L, Martin A, Mahendran R, Patel A, Murnane D, Page C, Dailey LA, Forbes B, Hutter V. Profiling alveolar macrophage responses to inhaled compounds using in vitro high content image analysis. Toxicol Appl Pharmacol 2023; 474:116608. [PMID: 37385476 DOI: 10.1016/j.taap.2023.116608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 07/01/2023]
Abstract
One of the main hurdles in the development of new inhaled medicines is the frequent observation of foamy macrophage (FM) responses in non-clinical studies in experimental animals, which raises safety concerns and hinders progress into clinical trials. We have investigated the potential of a novel multi-parameter high content image analysis (HCIA) assay as an in vitro safety screening tool to predict drug induced FM. Rat (NR8383) and human U937-derived alveolar macrophages were exposed in vitro to a panel of model compounds with different biological activity, including inhaled bronchodilators, inhaled corticosteroids (ICS), phospholipidosis inducers and proapoptotic agents. An HCIA was utilized to produce drug-induced cell response profiles based on individual cell health, morphology and lipid content parameters. The profiles of both rat and human macrophage cell lines differentiated between cell responses to marketed inhaled drugs and compounds known to induce phospholipidosis and apoptosis. Hierarchical clustering of the aggregated data allowed identification of distinct cell profiles in response to exposure to phospholipidosis and apoptosis inducers. Additionally, in NR8383 cell responses formed two distinct clusters, associated with increased vacuolation with or without lipid accumulation. U937 cells presented a similar trend but appeared less sensitive to drug exposure and presented a narrower range of responses. These results indicate that our multi-parameter HCIA assay is suitable to generate characteristic drug-induced macrophage response profiles, thus enabling differentiation of foamy macrophage phenotypes associated with phospholipidosis and apoptosis. This approach shows great potential as pre-clinical in vitro screening tool for safety assessment of candidate inhaled medicines.
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Affiliation(s)
- Ewelina Hoffman
- Centre for Topical Drug Delivery and Toxicology, School of Life and medical Sciences, University of Hertfordshire, Hatfield AL10 9AB, UK
| | - Laura Urbano
- Centre for Topical Drug Delivery and Toxicology, School of Life and medical Sciences, University of Hertfordshire, Hatfield AL10 9AB, UK
| | - Abigail Martin
- Centre for Topical Drug Delivery and Toxicology, School of Life and medical Sciences, University of Hertfordshire, Hatfield AL10 9AB, UK
| | - Rhamiya Mahendran
- Centre for Topical Drug Delivery and Toxicology, School of Life and medical Sciences, University of Hertfordshire, Hatfield AL10 9AB, UK
| | - Aateka Patel
- Centre for Topical Drug Delivery and Toxicology, School of Life and medical Sciences, University of Hertfordshire, Hatfield AL10 9AB, UK; Sackler Institute of Pulmonary Pharmacology, Faculty of Life Sciences & Medicine, Franklin-Wilkins Building, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Darragh Murnane
- Centre for Topical Drug Delivery and Toxicology, School of Life and medical Sciences, University of Hertfordshire, Hatfield AL10 9AB, UK.
| | - Clive Page
- Sackler Institute of Pulmonary Pharmacology, Faculty of Life Sciences & Medicine, Franklin-Wilkins Building, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Lea Ann Dailey
- Division of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, UZA II, Josef-Holaubek-Platz 2, 1090 Wien, Austria
| | - Ben Forbes
- King's College London, Institute of Pharmaceutical Science, London SE1 9NH, UK
| | - Victoria Hutter
- Centre for Topical Drug Delivery and Toxicology, School of Life and medical Sciences, University of Hertfordshire, Hatfield AL10 9AB, UK.
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Yamano S, Takeda T, Goto Y, Hirai S, Furukawa Y, Kikuchi Y, Kasai T, Misumi K, Suzuki M, Takanobu K, Senoh H, Saito M, Kondo H, Umeda Y. No evidence for carcinogenicity of titanium dioxide nanoparticles in 26-week inhalation study in rasH2 mouse model. Sci Rep 2022; 12:14969. [PMID: 36056156 PMCID: PMC9440215 DOI: 10.1038/s41598-022-19139-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/24/2022] [Indexed: 12/02/2022] Open
Abstract
With the rapid development of alternative methods based on the spirit of animal welfare, the publications of animal studies evaluating endpoints such as cancer have been extremely reduced. We performed a 26-week inhalation exposure studies of titanium dioxide nanoparticles (TiO2 NPs) using CByB6F1-Tg(HRAS)2Jic (rasH2) mice model for detecting carcinogenicity. Male and female rasH2 mice were exposed to 2, 8 or 32 mg/m3 of TiO2 NPs for 6 h/day, 5 days/week for 26 weeks. All tissues and blood were collected and subjected to biological and histopathological analyses. TiO2 NPs exposure induced deposition of particles in lungs in a dose-dependent manner in each exposure group. Exposure to TiO2 NPs, as well as other organs, did not increase the incidence of lung tumors in any group, and pulmonary fibrosis and pre-neoplastic lesions were not observed in all groups. Finally, the cell proliferative activity of alveolar epithelial type 2 cells was examined, and it was not increased by exposure to TiO2 NPs. This is the first report showing the lack of pulmonary fibrogenicity and carcinogenicity (no evidence of carcinogenic activity) of TiO2 NPs in 26-week inhalation study in rasH2 mice exposed up to 32 mg/m3, which is considered to be a high concentration.
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Affiliation(s)
- Shotaro Yamano
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan.
| | - Tomoki Takeda
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan.
| | - Yuko Goto
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Shigeyuki Hirai
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Yusuke Furukawa
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Yoshinori Kikuchi
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Tatsuya Kasai
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Kyohei Misumi
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Masaaki Suzuki
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Kenji Takanobu
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Hideki Senoh
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Misae Saito
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Hitomi Kondo
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Yumi Umeda
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
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McCunney RJ, Yong M, Warheit DB, Morfeld P. Occupational Exposure to Poorly Soluble Low Toxicity Particles and Cardiac Disease: A Look at Carbon Black and Titanium Dioxide. Front Public Health 2022; 10:909136. [PMID: 35968459 PMCID: PMC9374269 DOI: 10.3389/fpubh.2022.909136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Environmental particulate exposure and the potential risk to people with various types of cardiac diseases, most notably cardiovascular disease, have aroused scientific and regulatory interest worldwide. Epidemiological studies have shown associations between exposure to airborne environmental particulate matter (PM) and mortality from cardiovascular disease (CVD). The associations reported, however, are complex and may not involve a direct role for PM, since air pollutants are diverse and highly correlated. This study examines the potential role of occupational exposure to two types of particles, namely, manufactured carbon black (CB) and titanium dioxide (TiO2), on the risk of cardiovascular disease. To address the risk of cardiovascular disease from exposure to carbon black and titanium dioxide, as reflective of poorly soluble low toxicity particles, we reviewed the published cohort mortality studies of occupational exposure to carbon black and titanium dioxide. Mortality studies of carbon black have been conducted in the United States, Germany, and the United Kingdom. Five mortality studies related to workers involved in the manufacture of titanium dioxide in the United States and Europe have also been conducted. In addition, a meta-analysis of the three-carbon black mortality studies was performed. In the random-effects meta-analysis, full cohort meta-SMRs were 1.01 (95% confidence interval (CI): 0.79–1.29) for heart disease; 1.02 (95% CI: 0.80–1.30) for ischemic heart disease; and 1.08 (95% CI: 0.74–1.59) for acute myocardial infarction (AMI) mortality. A small but imprecise increased AMI mortality risk was suggested for cumulative exposure by a meta-HR = 1.10 per 100 mg/m3-years (95% CI: 0.92–1.31) but not for lugged exposures, that is, for recent exposures. Results of five cohort mortality studies of titanium dioxide workers in the United States and Europe showed no excess in all heart disease or cardiovascular disease. In the most recent study in the United States, an internal analysis, that is, within the cohort itself, with no lag time, showed that the exposure group 15–35 mg/m3-years yielded a significantly increased risk for heart disease; however, there was no evidence of increasing risk with increasing exposure for any of the exposure categories. In contrast to environmental studies, the results of cohort mortality studies do not demonstrate that airborne occupational exposure to carbon black and titanium dioxide particulates increases cardiovascular disease mortality. The lack of a relationship between carbon black and titanium dioxide and CVD mortality suggests that the associations reported in air pollution studies may not be driven by the particulate component.
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Affiliation(s)
- Robert J. McCunney
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
- *Correspondence: Robert J. McCunney
| | - Mei Yong
- MY EpiConsulting, Duesseldorf, Germany
| | | | - Peter Morfeld
- Institute and Policlinic for Occupational Medicine, Environmental Medicine and Prevention Research of Cologne University Hospital, Cologne, Germany
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Driscoll KE. Review of Lung Particle Overload, Rat Lung Cancer, and the Conclusions of the Edinburgh Expert Panel—It's Time to Revisit Cancer Hazard Classifications for Titanium Dioxide and Carbon Black. Front Public Health 2022; 10:907318. [PMID: 35968415 PMCID: PMC9366718 DOI: 10.3389/fpubh.2022.907318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
Chronic inhalation of titanium dioxide or carbon black by rats at concentrations which overload lung particle clearance can result in lung cancer. Based on this rat lung response, IARC, NIOSH, and ECHA classified titanium dioxide, and IARC classified carbon black, as potential human carcinogens. These classifications have been questioned based on an extensive data base demonstrating: the rat lung cancer occurred only under conditions of extreme lung particle overload; the lung cancer response in rats has not been seen in other animal species; and studies in titanium dioxide and carbon black exposed human populations have not shown an increased incidence of cancer. In 2019 an international panel of science and regulatory experts was convened to document the state of the science on lung particle overload and rat lung cancer after exposure to poorly soluble low toxicity particles. Regarding hazard identification, the expert panel concluded, in the absence of supporting data from other species, lung particle overload-associated rat lung cancer does not imply a cancer hazard for humans. Regarding high to low dose extrapolation, the expert panel concluded rat lung tumors occurring only under conditions of lung particle overload are not relevant to humans exposed under non-overloading conditions. The conclusions of the Edinburgh Expert Panel directly conflict with IARC, ECHA and NIOSH's extrapolation of lung particle overload associated rat lung cancer to hazard for humans. The hazard classifications for titanium dioxide and carbon black inhalation should be assessed considering the state-of-the-science on lung particle overload and rat lung cancer.
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11
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Mundt KA, Santamaria AB, Thompson WJ, Bates CA, Boles C, Dotson GS, Yong M. Carcinogenicity of Poorly Soluble Low Toxicity Particles: Commentary on Epidemiology as a Risk Assessment “Reality Check”. Front Public Health 2022; 10:920032. [PMID: 35903380 PMCID: PMC9315308 DOI: 10.3389/fpubh.2022.920032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Inhaled particles that are poorly soluble or insoluble and of low toxicity (“poorly soluble low toxicity” or “PSLT” particles), can accumulate in the lung and at lung overload levels induce lung cancers in rats. The question of whether PSLT particles increase lung cancer risk in humans is complicated by large differences between rats and humans and the relatively large particle doses administered in animal studies even when compared with heavy human occupational exposures. We review the findings of epidemiological studies on occupational exposure to each of three different PSLT particles (carbon black, talc and taconite). The epidemiological evidence indicates that at even very high occupational exposure levels at which non-malignant respiratory diseases including pneumoconiosis and even talcosis are observed, lung cancer risks appear not to be elevated. Although positive human cancer risks might be predicted based on extrapolation from overload doses in rats to relevant exposures in humans, the epidemiological “reality check” based on the three examples indicates that these PSLT particles are unlikely to increase lung cancer risk in humans even at high occupational levels of exposure. Therefore, we propose that careful evaluation of the epidemiological evidence can serve as a “reality check” for human risk assessment and help balance the risk evaluation process.
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Affiliation(s)
- Kenneth A. Mundt
- Cardno ChemRisk now Stantec, San Francisco, CA, United States
- *Correspondence: Kenneth A. Mundt
| | | | | | | | - Corey Boles
- Cardno ChemRisk now Stantec, San Francisco, CA, United States
| | - G. Scott Dotson
- Cardno ChemRisk now Stantec, San Francisco, CA, United States
| | - Mei Yong
- MY EpiConsulting, Düsseldorf, Germany
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Visser M, Gosens I, Bard D, van Broekhuizen P, Janer G, Kuempel E, Riediker M, Vogel U, Dekkers S. Towards health-based nano reference values (HNRVs) for occupational exposure: Recommendations from an expert panel. NANOIMPACT 2022; 26:100396. [PMID: 35560294 PMCID: PMC10617652 DOI: 10.1016/j.impact.2022.100396] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/23/2022] [Accepted: 03/11/2022] [Indexed: 06/15/2023]
Abstract
Unique physicochemical characteristics of engineered nanomaterials (ENMs) suggest the need for nanomaterial-specific occupational exposure limits (OELs). Setting these limits remains a challenge. Therefore, the aim of this study was to set out a framework to evaluate the feasibility of deriving advisory health-based occupational limit values for groups of ENMs, based on scientific knowledge. We have used an expert panel approach to address three questions: 1) What ENM-categories should be distinguished to derive advisory health-based occupational limit values (or health-based Nano Reference Values, HNRVs) for groups of ENMs? 2) What evidence would be needed to define values for these categories? And 3) How much effort would it take to achieve this? The panel experts distinguished six possible categories of HNRVs: A) WHO-fiber-like high aspect ratio ENMs (HARNs), B) Non-WHO-fiber-like HARNs and other non-spheroidal ENMs, C) readily soluble spheroidal ENMs, D) biopersistent spheroidal ENMs with unknown toxicity, E) biopersistent spheroidal ENMs with substance-specific toxicity and F) biopersistent spheroidal ENMs with relatively low substance-specific toxicity. For category A, the WHO-fiber-like HARNs, agreement was reached on criteria defining this category and the approach of using health-based risk estimates for asbestos to derive the HNRV. For category B, a quite heterogeneous category, more toxicity data are needed to set an HNRV. For category C, readily soluble spheroidal ENMs, using the OEL of their molecular or ionic counterpart would be a good starting point. For the biopersistent ENMs with unknown toxicity, HNRVs cannot be applied as case-by-case testing is required. For the other biopersistent ENMs in category E and F, we make several recommendations that can facilitate the derivation of these HNRVs. The proposed categories and recommendations as outlined by this expert panel can serve as a reference point for derivation of HNRVs when health-based OELs for ENMs are not yet available.
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Affiliation(s)
- Maaike Visser
- National Institute for Public Health and the Environment, Bilthoven, the Netherlands.
| | - Ilse Gosens
- National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | - Delphine Bard
- Health and Safety Executive (HSE) Science and Research Centre, Buxton, United Kingdom
| | | | - Gemma Janer
- Leitat Technological Center, Barcelona, Spain
| | - Eileen Kuempel
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | - Michael Riediker
- Swiss Centre for Occupational and Environmental Health, Winterthur, Switzerland
| | - Ulla Vogel
- National Research Centre for the Working Environment, Copenhagen, Denmark
| | - Susan Dekkers
- National Institute for Public Health and the Environment, Bilthoven, the Netherlands
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Burzlaff A, Creutzenberg O, Schaudien D, Viegas V, Danzeisen R, Warheit D. A tiered approach to investigate the inhalation toxicity of cobalt substances. Tier 4: Effects from a 28-day inhalation toxicity study with tricobalt tetraoxide in rats. Regul Toxicol Pharmacol 2022; 130:105129. [PMID: 35124138 DOI: 10.1016/j.yrtph.2022.105129] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/17/2022] [Accepted: 01/27/2022] [Indexed: 01/31/2023]
Abstract
Lung cancer following inhalation in rodents is a major concern regarding exposure to cobalt substances. However, little information is available on adverse effects and toxicity following long-term inhalation exposure to poorly soluble cobalt substances with low bioavailability. Thus, the present study focused on pulmonary effects of the poorly soluble tricobalt tetraoxide (5, 20, 80 mg/m³) in a 28-day inhalation exposure study. Lung weights increased with increasing exposures. Bronchoalveolar lavage fluid analysis and histopathology revealed lung tissue inflammation at the mid-dose with increasing severity in the high-dose group and post-exposure persistency. Markers for cellular damage and cell proliferation were statistically significantly increased. No increase in 8-OH-dG lesions was observed, indicating an absence of oxidative DNA lesions. The primary effect of inhaled Co3O4 particles is inflammation of the respiratory tract strongly resembling responses of inhaled "inert dust" substances, with a NOAEC of 5 mg/m³ under the conditions of this test.
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Affiliation(s)
- Arne Burzlaff
- EBRC Consulting GmbH, Raffaelstr. 4, 30177, Hannover, Germany.
| | - Otto Creutzenberg
- Fraunhofer Institute for Toxicology and Experimental Medicine (Fh-ITEM), Nikolai Fuchs Strasse 1, 30625, Hannover, Germany
| | - Dirk Schaudien
- Fraunhofer Institute for Toxicology and Experimental Medicine (Fh-ITEM), Nikolai Fuchs Strasse 1, 30625, Hannover, Germany
| | - Vanessa Viegas
- Cobalt Institute, 18 Jeffries Passage, Guildford, GU1 4AP, UK
| | - Ruth Danzeisen
- Cobalt Institute, 18 Jeffries Passage, Guildford, GU1 4AP, UK.
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14
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Replacement Strategies for Animal Studies in Inhalation Testing. SCI 2021. [DOI: 10.3390/sci3040045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Animal testing is mandatory in drug testing and is the gold standard for toxicity and efficacy evaluations. This situation is expected to change in the future as the 3Rs principle, which stands for the replacement, reduction, and refinement of the use of animals in science, is reinforced by many countries. On the other hand, technologies for alternatives to animal testing have increased. The need to develop and use alternatives depends on the complexity of the research topic and also on the extent to which the currently used animal models can mimic human physiology and/or exposure. The lung morphology and physiology of commonly used animal species differs from that of human lungs, and the realistic inhalation exposure of animals is challenging. In vitro and in silico methods can assess important aspects of the in vivo effects, namely particle deposition, dissolution, action at, and permeation through, the respiratory barrier, and pharmacokinetics. This review discusses the limitations of animal models and exposure systems and proposes in vitro and in silico techniques that could, when used together, reduce or even replace animal testing in inhalation testing in the future.
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15
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Cosnier F, Seidel C, Valentino S, Schmid O, Bau S, Vogel U, Devoy J, Gaté L. Retained particle surface area dose drives inflammation in rat lungs following acute, subacute, and subchronic inhalation of nanomaterials. Part Fibre Toxicol 2021; 18:29. [PMID: 34353337 PMCID: PMC8340536 DOI: 10.1186/s12989-021-00419-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 06/23/2021] [Indexed: 01/05/2023] Open
Abstract
Background An important aspect of nanomaterial (NM) risk assessment is establishing relationships between physicochemical properties and key events governing the toxicological pathway leading to adverse outcomes. The difficulty of NM grouping can be simplified if the most toxicologically relevant dose metric is used to assess the toxicological dose-response. 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. Inhalation studies were performed in rats with three classes of NMs: titanium dioxides (TiO2) and carbon blacks (CB) as poorly soluble particles of low toxicity (PSLT), and multiwall carbon nanotubes (MWCNTs). We compared our results to published data from nearly 30 rigorously selected articles. Results This analysis combined data specially generated for this work on three benchmark materials - TiO2 P25, the CB Printex-90 and the MWCNT MWNT-7 - following subacute (4-week) inhalation with published data 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 takes the form of sigmoid curves, and is independent of the post-exposure time. Curve fitting equations depended on the class of NM considered, and sometimes on the duration of exposure. 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 5 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. Conclusions Retained surface area is a useful metric for hazard grouping purposes. This metric would apply to both micrometric and nanometric materials, and could obviate the need for direct measurement in the lung. Indeed, it could alternatively be estimated from dosimetry models using the aerosol parameters (rigorously determined following a well-defined aerosol characterization strategy). Supplementary Information The online version contains supplementary material available at 10.1186/s12989-021-00419-w.
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Affiliation(s)
- Frédéric Cosnier
- Institut National de Recherche et de Sécurité, 1 Rue du Morvan, CS 60027, 54519, Vandœuvre-les-Nancy Cedex, France.
| | - Carole Seidel
- Institut National de Recherche et de Sécurité, 1 Rue du Morvan, CS 60027, 54519, Vandœuvre-les-Nancy Cedex, France
| | - Sarah Valentino
- Institut National de Recherche et de Sécurité, 1 Rue du Morvan, CS 60027, 54519, Vandœuvre-les-Nancy Cedex, France
| | - Otmar Schmid
- Institute of Lung Biology and Disease, Helmholtz Zentrum München, 85764, Neuherberg, Germany.,Comprehensive Pneumology Center, Munich (CPC-M) - Member of the German Center for Lung Research (DZL), 81377, Munich, Germany
| | - Sébastien Bau
- Institut National de Recherche et de Sécurité, 1 Rue du Morvan, CS 60027, 54519, Vandœuvre-les-Nancy Cedex, France
| | - Ulla Vogel
- National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100, Copenhagen, Denmark.,Department of Health Technology by DTU Food, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark
| | - Jérôme Devoy
- Institut National de Recherche et de Sécurité, 1 Rue du Morvan, CS 60027, 54519, Vandœuvre-les-Nancy Cedex, France
| | - Laurent Gaté
- Institut National de Recherche et de Sécurité, 1 Rue du Morvan, CS 60027, 54519, Vandœuvre-les-Nancy Cedex, France
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16
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Nymark P, Karlsson HL, Halappanavar S, Vogel U. Adverse Outcome Pathway Development for Assessment of Lung Carcinogenicity by Nanoparticles. FRONTIERS IN TOXICOLOGY 2021; 3:653386. [PMID: 35295099 PMCID: PMC8915843 DOI: 10.3389/ftox.2021.653386] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 03/26/2021] [Indexed: 12/13/2022] Open
Abstract
Lung cancer, one of the most common and deadly forms of cancer, is in some cases associated with exposure to certain types of particles. With the rise of nanotechnology, there is concern that some engineered nanoparticles may be among such particles. In the absence of epidemiological evidence, assessment of nanoparticle carcinogenicity is currently performed on a time-consuming case-by-case basis, relying mainly on animal experiments. Non-animal alternatives exist, including a few validated cell-based methods accepted for regulatory risk assessment of nanoparticles. Furthermore, new approach methodologies (NAMs), focused on carcinogenic mechanisms and capable of handling the increasing numbers of nanoparticles, have been developed. However, such alternative methods are mainly applied as weight-of-evidence linked to generally required animal data, since challenges remain regarding interpretation of the results. These challenges may be more easily overcome by the novel Adverse Outcome Pathway (AOP) framework, which provides a basis for validation and uptake of alternative mechanism-focused methods in risk assessment. Here, we propose an AOP for lung cancer induced by nanosized foreign matter, anchored to a selection of 18 standardized methods and NAMs for in silico- and in vitro-based integrated assessment of lung carcinogenicity. The potential for further refinement of the AOP and its components is discussed in relation to available nanosafety knowledge and data. Overall, this perspective provides a basis for development of AOP-aligned alternative methods-based integrated testing strategies for assessment of nanoparticle-induced lung cancer.
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Affiliation(s)
- Penny Nymark
- Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden
| | - Hanna L. Karlsson
- Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden
| | - Sabina Halappanavar
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Ulla Vogel
- National Research Centre for the Working Environment, Copenhagen, Denmark
- DTU Health Tech, Technical University of Denmark, Kgs. Lyngby, Denmark
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17
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Ladics GS, Price O, Kelkar S, Herkimer S, Anderson S. A Weight-of-the-Evidence Approach for Evaluating, in Lieu of Animal Studies, the Potential of a Novel Polysaccharide Polymer to Produce Lung Overload. Chem Res Toxicol 2021; 34:1430-1444. [PMID: 33881304 DOI: 10.1021/acs.chemrestox.0c00301] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The United States Environmental Protection Agency (EPA) is concerned about the respiratory effects caused by respirable particles of water-insoluble high molecular weight polymers. The EPA has proposed a tiered approach to evaluate polymer lung overload, a kinetic event. Kinetic polymer lung overload in itself is not necessarily adverse, however, inhalation of respirable particulate matter can have adverse effects (i.e., inflammation, fibrosis, etc.). If Tier I testing demonstrates that particles may reach the distal lung (i.e., a non-negligible amount of respirable particles/droplets ≤10 μm in diameter and lack of biosolubility), then animal inhalation testing in Tiers II-IV would be requested. In silico, in chemico, and in vitro alternatives should be considered versus in vivo testing for animal welfare purposes. An in chemico measure of biosolubility was used to demonstrate that a novel α-1,3-glucan polysaccharide, made by enzymatic polymerization of glucose from sucrose, is biosoluble and fits a simple exponential decay model with a half-life on the order of 66 days. The multiple-path particle dosimetry (MPPD) in silico model was used to predict lung burden for the novel α-1,3-glucan polysaccharide. MPPD was validated with measurements in rats exposed to a toner particulate and showed good agreement with lung burden measurements. A simulated 24 month rat exposure yielded 10-20 times less lung burden for the polysaccharide compared to the toner at equivalent exposure concentrations. The MPPD model was refined to include biosolubility data for the polysaccharide polymer. Data for amorphous silica were used to validate the clearance model, and the model incorporating dissolution predicted the amorphous silica lung burden within 20% of measured values. Human equivalent concentrations (HECs) were calculated for each toner rat exposure concentration. HECs were also determined for the polysaccharide at exposure concentrations yielding the same predicted internal doses as the toner. The in vitro, in chemico and in silico studies described here for the novel polysaccharide provide a useful weight of evidence approach in the absence of animal studies for the evaluation of polymer substances where polymer lung overload may be a concern.
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Affiliation(s)
- Gregory S Ladics
- IFF, 200 Powder Mill Road, Bldg. 353, Wilmington, Delaware 19803, United States
| | - Owen Price
- Applied Research Associates, Inc., 801 N. Quincy Street, Suite 700, Arlington, Virginia 22203, United States
| | - Shantanu Kelkar
- IFF, 200 Powder Mill Road, Bldg. 353, Wilmington, Delaware 19803, United States
| | - Scott Herkimer
- IFF, 200 Powder Mill Road, Bldg. 353, Wilmington, Delaware 19803, United States
| | - Shawn Anderson
- IFF, 200 Powder Mill Road, Bldg. 353, Wilmington, Delaware 19803, United States
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18
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Willhite CC, Karyakina NA, Nordheim E, Arnold I, Armstrong V, Momoli F, Shilnikova NS, Yenugadhati N, Krewski D. The REACH registration process: A case study of metallic aluminium, aluminium oxide and aluminium hydroxide. Neurotoxicology 2020; 83:166-178. [PMID: 33290785 DOI: 10.1016/j.neuro.2020.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The European Union's REACH Regulation requires determination of potential health and environmental effects of chemicals in commerce. The present case study examines the application of REACH guidance for health hazard assessments of three high production volume (HPV) aluminium (Al) substances: metallic aluminium, aluminium oxide, and aluminium hydroxide. Among the potential adverse health consequences of aluminium exposure, neurotoxicity is one of the most sensitive targets of Al toxicity and the most critical endpoint. This case study illustrates integration of data from multiple lines of evidence into REACH weight of evidence evaluations. This case study then explains how those results support regulatory decisions on classification and labelling. Challenges in the REACH appraisal of Al compounds include speciation, solubility and bioavailability, application of assessment factors, read-across rationale and differences with existing regulatory standards. Lessons learned from the present case study relate to identification and evaluation of toxicologic and epidemiologic data; assessing data relevance and reliability; development of derived no-effect levels (DNELs); addressing data gaps and preparation of chemical safety reports.
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Affiliation(s)
| | - Nataliya A Karyakina
- Risk Sciences International, Ottawa, Canada; McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada.
| | | | - Ian Arnold
- International Aluminium Institute, London, United Kingdom; Occupational Health Program, Faculty of Medicine, McGill University, Montreal, QC, Canada
| | | | - Franco Momoli
- Risk Sciences International, Ottawa, Canada; McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada; Faculty of Medicine, School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Natalia S Shilnikova
- Risk Sciences International, Ottawa, Canada; McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada
| | - Nagarajkumar Yenugadhati
- Risk Sciences International, Ottawa, Canada; Department of Epidemiology and Biostatistics, College of Public Health and Health Informatics, King Saud bin Abdul-Aziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Daniel Krewski
- Risk Sciences International, Ottawa, Canada; McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada; Faculty of Medicine, School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
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19
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Terry C, Yan Z, Corvaro M, Gehen SC. A retrospective study on EU harmonised classifications for carcinogenicity to guide future research. Regul Toxicol Pharmacol 2020; 119:104800. [PMID: 33129916 DOI: 10.1016/j.yrtph.2020.104800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/05/2020] [Accepted: 10/05/2020] [Indexed: 12/26/2022]
Abstract
Under European Regulation (EC) No 1272/2008 on the classification, labelling and packaging of substances and mixtures (CLP), chemicals can be classified as carcinogenic if they are considered to induce tumours, increase tumour incidence and/or malignancy, or shorten the time to tumour occurrence. Cancer classifications are divided into different hazard categories: Carc. 1A (known human carcinogen), Carc. 1B (presumed human carcinogen), Carc. 2 (suspected human carcinogen), and chemicals not classified for carcinogenicity. Selecting which classification is appropriate can be challenging, as judgements need to be made both on the existing hazard data and on its relevance to humans. One aspect to be considered in defining human relevance is a chemical's mode of action (MoA); the series of necessary key events that lead from an exposure to the adverse effect (in this case, tumours). This work aims to identify and discuss some of the features that have led ECHA's Committee for Risk Assessment (RAC) to decide upon harmonised cancer classifications for chemicals, and to prioritise future research on MoA and/or human relevance. RAC bases its decisions on cancer classification on both the weight-of-evidence (WoE) and strength-of-evidence (SoE) of this particular activity. Multiple factors contribute, including the species in which tumours are seen, and the relevance of the MoA to human health.
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Affiliation(s)
- Claire Terry
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, IN, USA.
| | - Zhongyu Yan
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, IN, USA.
| | - Marco Corvaro
- Corteva Agriscience, 3B Milton Park Square, OX14 4RN, Abingdon, UK.
| | - Sean C Gehen
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, IN, USA.
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20
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Hoffman E, Murnane D, Hutter V. Investigating the Suitability of High Content Image Analysis as a Tool to Assess the Reversibility of Foamy Alveolar Macrophage Phenotypes In Vitro. Pharmaceutics 2020; 12:pharmaceutics12030262. [PMID: 32183061 PMCID: PMC7150967 DOI: 10.3390/pharmaceutics12030262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/03/2020] [Accepted: 03/11/2020] [Indexed: 01/19/2023] Open
Abstract
Many potential inhaled medicines fail during development due to the induction of a highly vacuolated or “foamy” alveolar macrophage phenotype response in pre-clinical studies. There is limited understanding if this response to an inhaled stimulus is adverse or adaptive, and additionally if it is a transient or irreversible process. The aim of this study was to evaluate whether high content image analysis could distinguish between different drug-induced foamy macrophage phenotypes and to determine the extent of the reversibility of the foamy phenotypes by assessing morphological changes over time. Alveolar-like macrophages derived from the human monocyte cell line U937 were exposed for 24 h to compounds known to induce a foamy macrophage phenotype (amiodarone, staurosporine) and control compounds that are not known to cause a foamy macrophage phenotype in vitro (fluticasone and salbutamol). Following drug stimulation, the cells were rested in drug-free media for the subsequent 24 or 48 h. Cell morphometric parameters (cellular and nuclear area, vacuoles numbers and size) and phospholipid content were determined using high content image analysis. The foamy macrophage recovery was dependent on the mechanism of action of the inducer compound. Amiodarone toxicity was associated with phospholipid accumulation and morphometric changes were reversed when the stimulus was removed from culture environment. Conversely cells were unable to recover from exposure to staurosporine which initiates the apoptosis pathway. This study shows that high content analysis can discriminate between different phenotypes of foamy macrophages and may contribute to better decision making in the process of new drug development.
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21
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Driscoll KE, Borm PJA. Expert workshop on the hazards and risks of poorly soluble low toxicity particles. Inhal Toxicol 2020; 32:53-62. [DOI: 10.1080/08958378.2020.1735581] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Kevin E. Driscoll
- Healthcare Innovation Partners, Princeton, NJ, USA
- Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ, USA
| | - Paul J. A. Borm
- Nanoconsult BV, Meerssen, The Netherlands
- Dusseldorf University, Dusseldorf, Germany
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22
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Cox LA. Dose-response modeling of NLRP3 inflammasome-mediated diseases: asbestos, lung cancer, and malignant mesothelioma as examples. Crit Rev Toxicol 2020; 49:614-635. [PMID: 31905042 DOI: 10.1080/10408444.2019.1692779] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Can a single fiber of amphibole asbestos increase the risk of lung cancer or malignant mesothelioma (MM)? Traditional linear no-threshold (LNT) risk assessment assumptions imply that the answer is yes: there is no safe exposure level. This paper draws on recent scientific progress in inflammation biology, especially elucidation of the activation thresholds for NLRP3 inflammasomes and resulting chronic inflammation, to model dose-response relationships for malignant mesothelioma and lung cancer risks caused by asbestos exposures. The modeling integrates a physiologically based pharmacokinetics (PBPK) front end with inflammation-driven two-stage clonal expansion (I-TSCE) models of carcinogenesis to describe how exposure leads to chronic inflammation, which in turn promotes carcinogenesis. Together, the combined PBPK and I-TSCE modeling predict that there are practical thresholds for exposure concentration below which asbestos exposure does not cause chronic inflammation in less than a lifetime, and therefore does not increase chronic inflammation-dependent cancer risks. Quantitative examples using model parameter estimates drawn from the literature suggest that practical thresholds may be within about a factor of 2 of some past exposure levels for some workers. The I-TSCE modeling framework explains previous puzzling aspects of asbestos epidemiology, such as why age at first exposure is a better predictor of lifetime MM risk than exposure duration. It may be a valuable tool for risk analysts when LNT assumptions are not justified due to inflammation response thresholds mediating dose-response relationships.
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23
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Carbon Black and Lung Cancer Mortality—A Meta-regression Analysis Based on Three Occupational Cohort Studies. J Occup Environ Med 2019; 61:949-0. [DOI: 10.1097/jom.0000000000001713] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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24
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Sauer UG, Kreiling R. The Grouping and Assessment Strategy for Organic Pigments (GRAPE): Scientific evidence to facilitate regulatory decision-making. Regul Toxicol Pharmacol 2019; 109:104501. [PMID: 31629781 DOI: 10.1016/j.yrtph.2019.104501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/09/2019] [Accepted: 10/15/2019] [Indexed: 10/25/2022]
Abstract
This article presents the Grouping and Assessment Strategy for Organic Pigments (GRAPE). GRAPE is driven by the hypotheses that low (bio)dissolution and low permeability indicate absence of systemic bioavailability and hence no systemic toxicity potential upon oral exposure, and, for inhalation exposure, that low (bio)dissolution (and absence of surface reactivity, dispersibility and in vitro effects) indicate that the organic pigment is a 'poorly soluble particle without intrinsic toxicity potential'. In GRAPE Tier 1, (bio)solubility and (bio)dissolution are assessed, and in Tier 2, in vitro Caco-2 permeability and in vitro alveolar macrophage activation. Thereafter, organic pigments are grouped by common properties (further considering structural similarity depending on the regulatory requirements). In Tier 3, absence of systemic bioavailability is verified by limited in vivo screening (rat 28-day oral and 5-day inhalation toxicity studies). If Tier 3 confirms no (or only very low) systemic bioavailability, all higher-tier endpoint-specific animal testing is scientifically not-relevant. Application of the GRAPE can serve to reduce animal testing needs for all but few representative organic pigments within a group. GRAPE stands in line with the EU REACH Regulation (Registration, Evaluation, Authorisation and Restriction of Chemicals). An ongoing research project aims at establishing a proof-of-concept of the GRAPE.
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25
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Bos PMJ, Gosens I, Geraets L, Delmaar C, Cassee FR. Pulmonary toxicity in rats following inhalation exposure to poorly soluble particles: The issue of impaired clearance and the relevance for human health hazard and risk assessment. Regul Toxicol Pharmacol 2019; 109:104498. [PMID: 31604110 DOI: 10.1016/j.yrtph.2019.104498] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/04/2019] [Accepted: 10/07/2019] [Indexed: 11/19/2022]
Abstract
Intensive discussions are ongoing about the interpretation of pulmonary effects observed in rats exposed to poorly soluble particles. Alveolar clearance differs between rats and humans and becomes impaired in rats at higher exposure concentrations. Some have doubted the human relevance of toxic effects observed in rats under impaired clearance conditions and have suggested that experimental exposures should stay below concentrations inducing impaired clearance. However, for regulatory purposes, insight in potential health effects at relatively high concentrations is needed to fully understand the hazard. Many aspects of impaired particle clearance remain unclear, hampering human health hazard and risk assessment. For an adequate evaluation of the impact of impaired clearance on pulmonary toxicity, a clear definition of alveolar clearance is needed that enables to quantitatively relate the level of impairment to the induction of adverse pulmonary health effects. Also, information is needed on the mechanism of action and the appropriate dose metric for the pulmonary effects observed. In absence of these data, human hazard and risk assessment can only be performed in a pragmatic way. Unless available data clearly point out otherwise, rat pulmonary toxicity including lung inflammation and tumour formation, needs to be considered relevant for human hazard and risk assessment.
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Affiliation(s)
- Peter M J Bos
- National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | - Ilse Gosens
- National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | - Liesbeth Geraets
- National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | - Christiaan Delmaar
- National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | - Flemming R Cassee
- National Institute for Public Health and the Environment, Bilthoven, the Netherlands; Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands.
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Boffetta P, Fordyce T, Leonhard M. Evaluation of recent evidence on the solubility of beryllium compounds and cancer risk. Eur J Cancer Prev 2019; 29:186-190. [PMID: 31425313 DOI: 10.1097/cej.0000000000000526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Paolo Boffetta
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York
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Jamal QMS, Alharbi AH, Lohani M, Siddiqui MU, Ahmad V, Dhasmana A, Ansari MA, Siddiqui MH, Kesari KK. Elucidation of Scavenging Properties of Nanoparticles in the Prevention of Carcinogenicity Induced by Cigarette Smoke Carcinogens: An In Silico Study. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/978-3-319-96511-6_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
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Cox LAT. Risk Analysis Implications of Dose-Response Thresholds for NLRP3 Inflammasome-Mediated Diseases: Respirable Crystalline Silica and Lung Cancer as an Example. Dose Response 2019; 17:1559325819836900. [PMID: 31168301 PMCID: PMC6484684 DOI: 10.1177/1559325819836900] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 02/16/2019] [Accepted: 02/19/2019] [Indexed: 12/30/2022] Open
Abstract
Chronic inflammation mediates an extraordinarily wide range of diseases. Recent progress in understanding intracellular inflammasome assembly, priming, activation, cytokine signaling, and interactions with mitochondrial reactive oxygen species, lysosome disruption, cell death, and prion-like polymerization and spread of inflammasomes among cells, has potentially profound implications for dose-response modeling. This article discusses mechanisms of exposure concentration and duration thresholds for NOD-like receptor protein 3 (NLRP3)-mediated inflammatory responses and develops a simple biomathematical model of the onset of exposure-related tissue-level chronic inflammation and resulting disease risks, focusing on respirable crystalline silica (RCS) and lung cancer risk as an example. An inflammation-mediated 2-stage clonal expansion model of RCS-induced lung cancer is proposed that explains why relatively low estimated concentrations of RCS (eg, <1 mg/m3) do not increase lung cancer risk and why even high occupational concentrations increase risk only modestly (typically relative risk <2). The model of chronic inflammation implies a dose-response threshold for excess cancer risk, in contrast to traditional linear-no-threshold assumptions. If this implication is correct, then concentrations of crystalline silica (or amphibole asbestos fibers, or other environmental challenges that act via the NLRP3 inflammasome) below the threshold do not cause chronic inflammation and resulting elevated risks of inflammation-mediated diseases.
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Selley L, Phillips DH, Mudway I. The potential of omics approaches to elucidate mechanisms of biodiesel-induced pulmonary toxicity. Part Fibre Toxicol 2019; 16:4. [PMID: 30621739 PMCID: PMC6504167 DOI: 10.1186/s12989-018-0284-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 12/04/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Combustion of biodiesels in place of fossil diesel (FD) has been proposed as a method of reducing transport-related toxic emissions in Europe. While biodiesel exhaust (BDE) contains fewer hydrocarbons, total particulates and carbon monoxide than FD exhaust (FDE), its high nitrogen oxide and ultrafine particle content may still promote pulmonary pathophysiologies. MAIN BODY Using a complement of in vitro and in vivo studies, this review documents progress in our understanding of pulmonary responses to BDE exposure. Focusing initially on hypothesis-driven, targeted analyses, the merits and limitations of comparing BDE-induced responses to those caused by FDE exposure are discussed within the contexts of policy making and exploration of toxicity mechanisms. The introduction and progression of omics-led workflows are also discussed, summarising the novel insights into mechanisms of BDE-induced toxicity that they have uncovered. Finally, options for the expansion of BDE-related omics screens are explored, focusing on the mechanistic relevance of metabolomic profiling and offering rationale for expansion beyond classical models of pulmonary exposure. CONCLUSION Together, these discussions suggest that molecular profiling methods have identified mechanistically informative, novel and fuel-specific signatures of pulmonary responses to biodiesel exhaust exposure that would have been difficult to detect using traditional, hypothesis driven approaches alone.
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Affiliation(s)
- Liza Selley
- MRC Toxicology Unit, University of Cambridge, Hodgkin Building, Lancaster Road, Leicester, LE1 9HN UK
| | - David H. Phillips
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment & Health, School of Population Health and Environmental Sciences, Franklin-Wilkins Building, King’s College London, London, SE1 9NH UK
- NIHR HPRU in Health Impact of Environmental Hazards, Franklin-Wilkins Building, King’s College London, London, SE1 9NH UK
| | - Ian Mudway
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment & Health, School of Population Health and Environmental Sciences, Franklin-Wilkins Building, King’s College London, London, SE1 9NH UK
- NIHR HPRU in Health Impact of Environmental Hazards, Franklin-Wilkins Building, King’s College London, London, SE1 9NH UK
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30
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Bevan RJ, Kreiling R, Levy LS, Warheit DB. Toxicity testing of poorly soluble particles, lung overload and lung cancer. Regul Toxicol Pharmacol 2018; 100:80-91. [DOI: 10.1016/j.yrtph.2018.10.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 10/17/2018] [Accepted: 10/20/2018] [Indexed: 01/17/2023]
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31
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Møller P, Wallin H, Cassee FR, Loft S. Does intranasal instillation TiO 2 cause pulmonary tumorigenesis in male mice? ENVIRONMENTAL TOXICOLOGY 2018; 33:1095-1096. [PMID: 29055161 DOI: 10.1002/tox.22490] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 09/04/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Peter Møller
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Håkan Wallin
- National Institute of Occupational Health, Oslo, Norway
| | - Flemming R Cassee
- National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Steffen Loft
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
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Limo MJ, Sola-Rabada A, Boix E, Thota V, Westcott ZC, Puddu V, Perry CC. Interactions between Metal Oxides and Biomolecules: from Fundamental Understanding to Applications. Chem Rev 2018; 118:11118-11193. [PMID: 30362737 DOI: 10.1021/acs.chemrev.7b00660] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Metallo-oxide (MO)-based bioinorganic nanocomposites promise unique structures, physicochemical properties, and novel biochemical functionalities, and within the past decade, investment in research on materials such as ZnO, TiO2, SiO2, and GeO2 has significantly increased. Besides traditional approaches, the synthesis, shaping, structural patterning, and postprocessing chemical functionalization of the materials surface is inspired by strategies which mimic processes in nature. Would such materials deliver new technologies? Answering this question requires the merging of historical knowledge and current research from different fields of science. Practically, we need an effective defragmentation of the research area. From our perspective, the superficial accounting of material properties, chemistry of the surfaces, and the behavior of biomolecules next to such surfaces is a problem. This is particularly of concern when we wish to bridge between technologies in vitro and biotechnologies in vivo. Further, besides the potential practical technological efficiency and advantages such materials might exhibit, we have to consider the wider long-term implications of material stability and toxicity. In this contribution, we present a critical review of recent advances in the chemistry and engineering of MO-based biocomposites, highlighting the role of interactions at the interface and the techniques by which these can be studied. At the end of the article, we outline the challenges which hamper progress in research and extrapolate to developing and promising directions including additive manufacturing and synthetic biology that could benefit from molecular level understanding of interactions occurring between inanimate (abiotic) and living (biotic) materials.
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Affiliation(s)
- Marion J Limo
- Interdisciplinary Biomedical Research Centre, School of Science and Technology , Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS , United Kingdom.,Interface and Surface Analysis Centre, School of Pharmacy , University of Nottingham , University Park, Nottingham NG7 2RD , United Kingdom
| | - Anna Sola-Rabada
- Interdisciplinary Biomedical Research Centre, School of Science and Technology , Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS , United Kingdom
| | - Estefania Boix
- Interdisciplinary Biomedical Research Centre, School of Science and Technology , Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS , United Kingdom.,Department of Bioproducts and Biosystems , Aalto University , P.O. Box 16100, FI-00076 Aalto , Finland
| | - Veeranjaneyulu Thota
- Interdisciplinary Biomedical Research Centre, School of Science and Technology , Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS , United Kingdom
| | - Zayd C Westcott
- Interdisciplinary Biomedical Research Centre, School of Science and Technology , Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS , United Kingdom
| | - Valeria Puddu
- Interdisciplinary Biomedical Research Centre, School of Science and Technology , Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS , United Kingdom
| | - Carole C Perry
- Interdisciplinary Biomedical Research Centre, School of Science and Technology , Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS , United Kingdom
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Dekkers S, Ma-Hock L, Lynch I, Russ M, Miller MR, Schins RPF, Keller J, Römer I, Küttler K, Strauss V, De Jong WH, Landsiedel R, Cassee FR. Differences in the toxicity of cerium dioxide nanomaterials after inhalation can be explained by lung deposition, animal species and nanoforms. Inhal Toxicol 2018; 30:273-286. [PMID: 30286672 DOI: 10.1080/08958378.2018.1516834] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Considerable differences in pulmonary responses have been observed in animals exposed to cerium dioxide nanoparticles via inhalation. These differences in pulmonary toxicity might be explained by differences in lung deposition, species susceptibility or physicochemical characteristics of the tested cerium dioxide nanoforms (i.e. same chemical substance, different size, shape, surface area or surface chemistry). In order to distinguish the relative importance of these different influencing factors, we performed a detailed analysis of the data from several inhalation studies with different exposure durations, species and nanoforms, namely published data on NM211 and NM212 (JRC repository), NanoAmor (commercially available) and our published and unpublished data on PROM (industry provided). Data were analyzed by comparing the observed pulmonary responses at similar external and internal dose levels. Our analyses confirm that rats are more sensitive to developing pulmonary inflammation compared to mice. The observed differences in responses do not result purely from differences in the delivered and retained doses (expressed in particle mass as well as surface area). In addition, the different nanoforms assessed showed differences in toxic potency likely due to differences in their physicochemical parameters. Primary particle and aggregate/agglomerate size distributions have a substantial impact on the deposited dose and consequently on the pulmonary response. However, in our evaluation size could not fully explain the difference observed in the analyzed studies indicating that the pulmonary response also depends on other physicochemical characteristics of the particles. It remains to be determined to what extent these findings can be generalized to other poorly soluble nanomaterials.
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Affiliation(s)
- Susan Dekkers
- a National Institute for Public Health and the Environment , Bilthoven , The Netherlands
| | - Lan Ma-Hock
- b Experimental Toxicology and Ecology, BASF SE , Ludwigshafen , Germany
| | - Iseult Lynch
- c School of Geography, Earth and Environmental Sciences , University of Birmingham , Edgbaston , UK
| | - Mike Russ
- d Promethean Particles Ltd , Nottingham , UK
| | - Mark R Miller
- e Centre for Cardiovascular Science University of Edinburgh , Edinburgh , UK
| | - Roel P F Schins
- f IUF - Leibniz Research Institute for Environmental Medicine , Düsseldorf , Germany
| | - Jana Keller
- b Experimental Toxicology and Ecology, BASF SE , Ludwigshafen , Germany
| | - Isabella Römer
- c School of Geography, Earth and Environmental Sciences , University of Birmingham , Edgbaston , UK
| | - Karin Küttler
- b Experimental Toxicology and Ecology, BASF SE , Ludwigshafen , Germany
| | - Volker Strauss
- b Experimental Toxicology and Ecology, BASF SE , Ludwigshafen , Germany
| | - Wim H De Jong
- a National Institute for Public Health and the Environment , Bilthoven , The Netherlands
| | - Robert Landsiedel
- b Experimental Toxicology and Ecology, BASF SE , Ludwigshafen , Germany
| | - Flemming R Cassee
- a National Institute for Public Health and the Environment , Bilthoven , The Netherlands.,g Institute for Risk Assessment Sciences, Utrecht University , Utrecht , The Netherlands
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Steiling W, Almeida JF, Assaf Vandecasteele H, Gilpin S, Kawamoto T, O'Keeffe L, Pappa G, Rettinger K, Rothe H, Bowden AM. Principles for the safety evaluation of cosmetic powders. Toxicol Lett 2018; 297:8-18. [PMID: 30125618 DOI: 10.1016/j.toxlet.2018.08.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 08/13/2018] [Accepted: 08/16/2018] [Indexed: 11/15/2022]
Abstract
Consumer exposure to cosmetic (personal care) products is mostly by dermal contact, however additional considerations with regards to potential inhalation exposure from some cosmetics, such as sprays and powders, may be needed for a robust and reliable safety assessment. To get a deeper understanding of the exposure to airborne particles and droplets during product application, a team of international experts was founded under the umbrella of the European Association of the Cosmetic Industry "Cosmetics Europe" (CE) in Brussels. This expert team has worked out a pragmatic strategy how small and medium sized enterprises (SMEs), but also relevant authorities, could handle the safety evaluation of cosmetic powder products. Sufficient information on the aerodynamic diameter of sprayed droplets and here specifically of airborne particles is essential in addition to knowing the exposure after typical product application. The current article is focused on the determination of inhalation exposure to solids, and the derivation of safe exposure levels for cosmetic powder products found in the market. The principles described herein are very similar to spray products as published earlier and should be applied in a similar way (Steiling et al., 2014). Prediction models for the best estimate of inhalation exposure, developed with data from computer simulation programs, individual real-time measurements or finally by experience from the market were introduced and applied. Safety assessment approaches for exposure from powder spray products were developed and have been already considered in regulatory guidelines like the EC Cosmetics Regulation.
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Affiliation(s)
- W Steiling
- Henkel AG & Co KGaA, Henkelstr. 67, D-40191, Düsseldorf, Germany.
| | - J F Almeida
- Cosmetics Europe-The Personal Care Association Avenue Herrmann-Debroux 40, 1160, Brussels, Belgium
| | | | - S Gilpin
- The Estée Lauder Companies Inc., Research and Development, 155 Pinelawn Rd., Suite 300S, Melville, NY, 11363, United States
| | - T Kawamoto
- Kao Germany GmbH, Pfungstädter Str. 98-100, D-64297, Darmstadt, Germany
| | - L O'Keeffe
- Procter & Gamble, Whitehall Lane, Egham, Surrey, TW20 9NW, UK
| | - G Pappa
- Beiersdorf AG, Unnastrasse 48, D-20245, Hamburg, Germany
| | - K Rettinger
- IKW, The German Cosmetic, Toiletry, Perfumery and Detergent Association, Frankfurt, Germany
| | - H Rothe
- Coty, Berliner Allee 65, D-64274, Darmstadt, Germany
| | - A M Bowden
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire, MK44 1LQ, UK
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A Review and Meta-Analysis of Occupational Titanium Dioxide Exposure and Lung Cancer Mortality. J Occup Environ Med 2018. [DOI: 10.1097/jom.0000000000001314] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Schulte PA, Kuempel ED, Drew NM. Characterizing risk assessments for the development of occupational exposure limits for engineered nanomaterials. Regul Toxicol Pharmacol 2018; 95:207-219. [PMID: 29574195 PMCID: PMC6075708 DOI: 10.1016/j.yrtph.2018.03.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/05/2018] [Accepted: 03/20/2018] [Indexed: 12/16/2022]
Abstract
The commercialization of engineered nanomaterials (ENMs) began in the early 2000's. Since then the number of commercial products and the number of workers potentially exposed to ENMs is growing, as is the need to evaluate and manage the potential health risks. Occupational exposure limits (OELs) have been developed for some of the first generation of ENMs. These OELs have been based on risk assessments that progressed from qualitative to quantitative as nanotoxicology data became available. In this paper, that progression is characterized. It traces OEL development through the qualitative approach of general groups of ENMs based primarily on read-across with other materials to quantitative risk assessments for nanoscale particles including titanium dioxide, carbon nanotubes and nanofibers, silver nanoparticles, and cellulose nanocrystals. These represent prototypic approaches to risk assessment and OEL development for ENMs. Such substance-by-substance efforts are not practical given the insufficient data for many ENMs that are currently being used or potentially entering commerce. Consequently, categorical approaches are emerging to group and rank ENMs by hazard and potential health risk. The strengths and limitations of these approaches are described, and future derivations and research needs are discussed. Critical needs in moving forward with understanding the health effects of the numerous EMNs include more standardized and accessible quantitative data on the toxicity and physicochemical properties of ENMs.
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Affiliation(s)
- P A Schulte
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, United States.
| | - E D Kuempel
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, United States
| | - N M Drew
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, United States
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Bierkandt FS, Leibrock L, Wagener S, Laux P, Luch A. The impact of nanomaterial characteristics on inhalation toxicity. Toxicol Res (Camb) 2018; 7:321-346. [PMID: 30090585 PMCID: PMC6060709 DOI: 10.1039/c7tx00242d] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 01/31/2018] [Indexed: 12/27/2022] Open
Abstract
During the last few decades, nanotechnology has evolved into a success story, apparent from a steadily increasing number of scientific publications as well as a large number of applications based on engineered nanomaterials (ENMs). Its widespread uses suggest a high relevance for consumers, workers and the environment, hence justifying intensive investigations into ENM-related adverse effects as a prerequisite for nano-specific regulations. In particular, the inhalation of airborne ENMs, being assumed to represent the most hazardous type of human exposure to these kinds of particles, needs to be scrutinized. Due to an increased awareness of possible health effects, which have already been seen in the case of ultrafine particles (UFPs), research and regulatory measures have set in to identify and address toxic implications following their almost ubiquitous occurrence. Although ENM properties differ from those of the respective bulk materials, the available assessment protocols are often designed for the latter. Despite the large benefit ensuing from the application of nanotechnology, many issues related to ENM behavior and adverse effects are not fully understood or should be examined anew. The traditional hypothesis that ENMs exhibit different or additional hazards due to their "nano" size has been challenged in recent years and ENM categorization according to their properties and toxicity mechanisms has been proposed instead. This review summarizes the toxicological effects of inhaled ENMs identified to date, elucidating the modes of action which provoke different mechanisms in the respiratory tract and their resulting effects. By linking particular mechanisms and adverse effects to ENM properties, grouping of ENMs based on toxicity-related properties is supposed to facilitate toxicological risk assessment. As intensive studies are still required to identify these "ENM classes", the need for alternatives to animal studies is evident and advances in cell-based test systems for pulmonary research are presented here. We hope to encourage the ongoing discussion about ENM risks and to advocate the further development and practice of suitable testing and grouping methods.
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Affiliation(s)
- Frank S Bierkandt
- German Federal Institute of Risk Assessment (BfR) , Department of Chemical and Product Safety , Max-Dohrn-Strasse 8-10 , 10589 Berlin , Germany . ; Tel: (+49) 30 18412-4538
| | - Lars Leibrock
- German Federal Institute of Risk Assessment (BfR) , Department of Chemical and Product Safety , Max-Dohrn-Strasse 8-10 , 10589 Berlin , Germany . ; Tel: (+49) 30 18412-4538
| | - Sandra Wagener
- German Federal Institute of Risk Assessment (BfR) , Department of Chemical and Product Safety , Max-Dohrn-Strasse 8-10 , 10589 Berlin , Germany . ; Tel: (+49) 30 18412-4538
| | - Peter Laux
- German Federal Institute of Risk Assessment (BfR) , Department of Chemical and Product Safety , Max-Dohrn-Strasse 8-10 , 10589 Berlin , Germany . ; Tel: (+49) 30 18412-4538
| | - Andreas Luch
- German Federal Institute of Risk Assessment (BfR) , Department of Chemical and Product Safety , Max-Dohrn-Strasse 8-10 , 10589 Berlin , Germany . ; Tel: (+49) 30 18412-4538
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Chaudhuri I, Fruijtier-Pölloth C, Ngiewih Y, Levy L. Evaluating the evidence on genotoxicity and reproductive toxicity of carbon black: a critical review. Crit Rev Toxicol 2017; 48:143-169. [DOI: 10.1080/10408444.2017.1391746] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Ishrat Chaudhuri
- Safety, Health and Environment, Cabot Corporation, Billerica, MA, USA
| | | | | | - Len Levy
- School of Water, Energy and Environment, Cranfield University, Cranfield, UK
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