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Paris C, Thaon I, Laurent F, Saade A, Andujar P, Brochard P, Benoist J, Clin B, Ferretti G, Gislard A, Gramond C, Wild P, Lacourt A, Delva F, Pairon JC. Pleural Plaques and the Role of Exposure to Mineral Particles in the Asbestos Post-Exposure Survey. Chest 2023:S0012-3692(23)00176-9. [PMID: 36773934 DOI: 10.1016/j.chest.2023.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 01/18/2023] [Accepted: 02/02/2023] [Indexed: 02/12/2023] Open
Abstract
BACKGROUND Previous studies have inconsistently reported associations between refractory ceramic fibers (RCFs) or mineral wool fibers (MWFs) and the presence of pleural plaques (PPs). All these studies were based on chest radiographs, known to be associated with a poor sensitivity for the diagnosis of PP. RESEARCH QUESTION Does the risk of PPs increase with cumulative exposure to RCFs, MWFs, and silica? If the risk does increase, do these dose-response relationships depend on the co-exposure to asbestos or, conversely, are the dose-response relationships for asbestos modified by co-exposure to RCFs, MWFs, and silica? STUDY DESIGN AND METHODS Volunteer workers were invited to participate in a CT scan screening program for asbestos-related diseases in France. Asbestos exposure was assessed by industrial hygienists, and exposure to RCFs, MWFs, and silica was determined by using job-exposure matrices. A cumulative exposure index (CEI) was then calculated for each subject and separately for each of the four mineral particle exposures. All available CT scans were submitted to randomized, double reading by a panel of radiologists. RESULTS In this cohort of 5,457 subjects, significant dose-response relationships were determined after adjustment for asbestos exposure between CEI to RCF or MWF and the risk of PPs (ORs of 1.29 [95% CI, 1.00-1.67] and 1.84 [95% CI, 1.49-2.27] for the highest CEI quartile, respectively). Significant interactions were found between asbestos on one hand and MWF or RCF on the other. INTERPRETATION This study suggests the existence of a significant association between exposure to RCFs and MWFs and the presence of PPs in a large population previously exposed to asbestos and screened by using CT scans.
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Affiliation(s)
- Christophe Paris
- Centre de Pathologies Professionnelles et environnementales, CHU Pontchaillou, Rennes, France; INSERM, IRSET U1085, Equipe ESTER, Rennes, France.
| | - Isabelle Thaon
- CHRU de Nancy, Université de Lorraine, Centre de Consultation de Pathologies Professionnelles, Nancy, France
| | - François Laurent
- Service d'imagerie médicale diagnostique et thérapeutique, Unité d'imagerie thoracique CHHU de Bordeaux groupe hospitalier Sud Avenue de Magellan, Pessac, France; Centre de recherche cardiothoracique, INSERM U1045, Bordeaux, France
| | - Anastasia Saade
- Centre de Pathologies Professionnelles et environnementales, CHU Pontchaillou, Rennes, France; INSERM, IRSET U1085, Equipe ESTER, Rennes, France
| | - Pascal Andujar
- Univ Paris Est Créteil, INSERM, IMRB, Equipe GEIC2O, Creteil, France; Centre Hospitalier Intercommunal, Service de Pathologies professionnelles et de l'Environnement, Institut Santé-Travail Paris-Est, Creteil, France
| | - Patrick Brochard
- Université Bordeaux, INSERM, Bordeaux Population Health Research Center, Epicene Team, UMR 1219, Bordeaux, France
| | - Julia Benoist
- Centre Hospitalier Intercommunal, Service de Pathologies professionnelles et de l'Environnement, Institut Santé-Travail Paris-Est, Creteil, France
| | - Benedicte Clin
- INSERM U1086, ANTICIPE, Caen, France; Université de Caen Normandie, Caen, France; CHU Caen, Service de santé au travail et pathologie professionnelle, Caen, France
| | - Gilbert Ferretti
- Service de radiologie diagnostique et thérapeutique, Hôpital Michallon, CHU Grenoble Alpes, Grenoble, France; Université Grenoble Alpes, La Tronche, France
| | - Antoine Gislard
- Centre de Pathologies Professionnelles et environnementales, CHU Rouen, Rouen, France
| | - Cecile Gramond
- Université Bordeaux, INSERM, Bordeaux Population Health Research Center, Epicene Team, UMR 1219, Bordeaux, France
| | - Pascal Wild
- INRS, French Institute for Research and Safety, Vandoeuvre-Les-Nancy, France
| | - Aude Lacourt
- Université Bordeaux, INSERM, Bordeaux Population Health Research Center, Epicene Team, UMR 1219, Bordeaux, France
| | - Fleur Delva
- Université Bordeaux, INSERM, Bordeaux Population Health Research Center, Epicene Team, UMR 1219, Bordeaux, France
| | - Jean-Claude Pairon
- Univ Paris Est Créteil, INSERM, IMRB, Equipe GEIC2O, Creteil, France; Centre Hospitalier Intercommunal, Service de Pathologies professionnelles et de l'Environnement, Institut Santé-Travail Paris-Est, Creteil, France
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Cui Y, Huang L, Huo T, Dong F, Wang G, Zhang Q. Man-made mineral fiber effects on the expression of anti-oncogenes P53 and P16 and oncogenes C-JUN and C-FOS in the lung tissue of Wistar rats. Toxicol Ind Health 2019; 35:431-444. [PMID: 31131716 DOI: 10.1177/0748233719851699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Man-made mineral fibers (MMMFs) are substitutes for asbestos. MMMFs are widely used as insulation, but their molecular mechanisms underlying the tumorigenic effects in vivo have been poorly studied. For this reason, this work aimed to explore the properties and carcinogenic molecular mechanisms of MMMFs. The three MMMFs, rock wool (RW), glass fibers (GFs), and ceramic fibers (CFs), were prepared into respirable dust. Particle size, morphology, and chemical composition were analyzed by laser particle analyzer, scanning electron microscope, and X-ray fluorescence spectrometer, respectively. The Wistar rats were administered multiple intratracheal instillations of three MMMFs once a month. Then, several parameters (e.g. body mass, lung mass, and lung histology) were measured at 1, 3, and 6 months. After that, levels of P53, P16, C-JUN, and C-FOS mRNA and protein were measured by quantitative real-time reverse transcription polymerase chain reaction and Western blotting. This work found that exposure to MMMFs could influence the growth of body mass and increase lung mass. General conditions showed white nodules and irregular atrophy. In addition, MMMFs could lead to inactivation of anti-oncogene P16 and activation of proto-oncogenes (C-JUN and C-FOS) in the mRNA and protein levels, in which GF and CF were more obvious compared with RW. The effect of MMMFs was different, which may be related to the physical and chemical characteristics of different MMMFs. In conclusion, MMMFs (GF and CF) could induce an unbalanced expression of cancer-related genes in the lung tissues of rats. The understanding of the determinants of toxicity and carcinogenicity provides a scientific basis for developing and introducing new safer MMMF products, and the present study provides some useful insights into the carcinogenic mechanism of MMMFs.
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Affiliation(s)
- Yan Cui
- 1 School of Public Health, Southwest Medical University, Luzhou, China
| | - Liuwen Huang
- 2 School of Pharmacy, Southwest Medical University, Luzhou, China
| | - Tingting Huo
- 3 Key Laboratory of Solid Waste Treatment and the Resource Recycle, Southwest University of Science and Technology, Mianyang, China
| | - Faqin Dong
- 3 Key Laboratory of Solid Waste Treatment and the Resource Recycle, Southwest University of Science and Technology, Mianyang, China
| | - Guojun Wang
- 4 Department of Pharmacy, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Qingbi Zhang
- 1 School of Public Health, Southwest Medical University, Luzhou, China
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A comparison of the results from intra-pleural and intra-peritoneal studies with those from inhalation and intratracheal tests for the assessment of pulmonary responses to inhalable dusts and fibres. Regul Toxicol Pharmacol 2016; 81:89-105. [DOI: 10.1016/j.yrtph.2016.07.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Revised: 07/20/2016] [Accepted: 07/28/2016] [Indexed: 02/01/2023]
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Expert consensus on an in vitro approach to assess pulmonary fibrogenic potential of aerosolized nanomaterials. Arch Toxicol 2016; 90:1769-83. [PMID: 27121469 PMCID: PMC4894935 DOI: 10.1007/s00204-016-1717-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 04/18/2016] [Indexed: 12/11/2022]
Abstract
The increasing use of multi-walled carbon nanotubes (MWCNTs) in consumer products and their potential to induce adverse lung effects following inhalation has lead to much interest in better understanding the hazard associated with these nanomaterials (NMs). While the current regulatory requirement for substances of concern, such as MWCNTs, in many jurisdictions is a 90-day rodent inhalation test, the monetary, ethical, and scientific concerns associated with this test led an international expert group to convene in Washington, DC, USA, to discuss alternative approaches to evaluate the inhalation toxicity of MWCNTs. Pulmonary fibrosis was identified as a key adverse outcome linked to MWCNT exposure, and recommendations were made on the design of an in vitro assay that is predictive of the fibrotic potential of MWCNTs. While fibrosis takes weeks or months to develop in vivo, an in vitro test system may more rapidly predict fibrogenic potential by monitoring pro-fibrotic mediators (e.g., cytokines and growth factors). Therefore, the workshop discussions focused on the necessary specifications related to the development and evaluation of such an in vitro system. Recommendations were made for designing a system using lung-relevant cells co-cultured at the air–liquid interface to assess the pro-fibrogenic potential of aerosolized MWCNTs, while considering human-relevant dosimetry and NM life cycle transformations. The workshop discussions provided the fundamental design components of an air–liquid interface in vitro test system that will be subsequently expanded to the development of an alternative testing strategy to predict pulmonary toxicity and to generate data that will enable effective risk assessment of NMs.
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Lippmann M. Toxicological and epidemiological studies on effects of airborne fibers: coherence and public [corrected] health implications. Crit Rev Toxicol 2015; 44:643-95. [PMID: 25168068 DOI: 10.3109/10408444.2014.928266] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Airborne fibers, when sufficiently biopersistent, can cause chronic pleural diseases, as well as excess pulmonary fibrosis and lung cancers. Mesothelioma and pleural plaques are caused by biopersistent fibers thinner than ∼0.1 μm and longer than ∼5 μm. Excess lung cancer and pulmonary fibrosis are caused by biopersistent fibers that are longer than ∼20 μm. While biopersistence varies with fiber type, all amphibole and erionite fibers are sufficiently biopersistent to cause pathogenic effects, while the greater in vivo solubility of chrysotile fibers makes them somewhat less causal for the lung diseases, and much less causal for the pleural diseases. Most synthetic vitreous fibers are more soluble in vivo than chrysotile, and pose little, if any, health pulmonary or pleural health risk, but some specialty SVFs were sufficiently biopersistent to cause pathogenic effects in animal studies. My conclusions are based on the following: 1) epidemiologic studies that specified the origin of the fibers by type, and especially those that identified their fiber length and diameter distributions; 2) laboratory-based toxicologic studies involving fiber size characterization and/or dissolution rates and long-term observation of biological responses; and 3) the largely coherent findings of the epidemiology and the toxicology. The strong dependence of effects on fiber diameter, length, and biopersistence makes reliable routine quantitative exposure and risk assessment impractical in some cases, since it would require transmission electronic microscopic examination, of representative membrane filter samples, for determining statistically sufficient numbers of fibers longer than 5 and 20 μm, and those thinner than 0.1 μm, based on the fiber types.
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Affiliation(s)
- Morton Lippmann
- Department of Environmental Medicine, New York University School of Medicine , Tuxedo, NY , USA
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Morimoto Y, Horie M, Kobayashi N, Shinohara N, Shimada M. Inhalation toxicity assessment of carbon-based nanoparticles. Acc Chem Res 2013; 46:770-81. [PMID: 22574947 DOI: 10.1021/ar200311b] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although the demand for nanomaterials has grown, researchers have not conclusively determined the effects of nanomaterials on the human body. To understand the effects of nanomaterials on occupational health, we need to estimate the respiratory toxicity of nanomaterials through inhalation studies, intratracheal instillation studies, and pharyngeal aspiration studies. The discrepancies observed among these studies tend to result from differences in the physiochemical properties of nanomaterials, such as aggregation and dispersion. Therefore, in all toxicity studies, identification of the physicochemical properties of nanomaterials is essential. This Account reviews the inhalation toxicity of manufactured nanomaterials and compares them with inhalation and intratracheal instillation studies of well-characterized fullerene and carbon nanotubes. In many reports, pulmonary inflammation and injury served as pulmonary endpoints for the inhalation toxicity. To assess pulmonary inflammation, we examined neutrophil and macrophage infiltration in the alveolar and/or interstitial space, and the expression of the neutrophil and/or monocyte chemokines. We also reported the release of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) in the bronchoalveolar lavage fluid (BALF), the expression of oxidative stress-related genes characteristic of lung injury, and the presence of granulomatous lesion and pulmonary fibrosis. In the inhalation and intratracheal instillation studies of well-characterized fullerenes, exposure to fullerene did not induce pulmonary inflammation or transient inflammation. By contrast, in an inhalation study, a high concentration of multiwall carbon nanotubes (MWCNTs) and single-wall carbon nanotubes (SWCNTs) induced neutrophil inflammation or granulomatous formations in the lung, and intratracheal instillation of MWCNTs and SWCNTs induced persistent inflammation in the lung. Among the physicochemical properties of carbon nanotubes, the increased surface area is associated with inflammatory activity as measured by the increase in the rate of neutrophils measured in bronchoalveolar lavage fluid. Metal impurities such as iron and nickel enhanced the pulmonary toxicity of carbon nanotubes, and SWCNTs that included an amorphous carbon induced multifocal granulomas in the lung while purer SWCNTs did not. The aggregation state also affects pulmonary response: Exposure to well-dispersed carbon nanotubes led to the thickening of the alveolar wall and fewer granulomatous lesions in the lung, while agglomerated carbon nanotubes produced granulomatous inflammation. The values of the acceptable exposure concentration in some countries were based on the data of subacute and subchronic inhalation and intratracheal instillation studies of well-characterized fullerene and carbon nanotubes. In Japan, the acceptable exposure concentration of fullerene is 0.39 mg/m³. In Europe, the proposal concentration is 44.4 μg/m³ for acute toxicity and 0.27 μg/m³ for chronic toxicity. The proposal acceptable exposure concentrations of carbon nanotubes are 0.03, 0.05, and 0.007 mg/m³ in Japan, Europe, and the United States, respectively.
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Affiliation(s)
- Yasuo Morimoto
- Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health (UOEH), Japan
| | - Masanori Horie
- Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health (UOEH), Japan
| | | | - Naohide Shinohara
- Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology (AIST), Japan
| | - Manabu Shimada
- Graduate School of Engineering, Hiroshima University, Japan
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Mossman BT, Lippmann M, Hesterberg TW, Kelsey KT, Barchowsky A, Bonner JC. Pulmonary endpoints (lung carcinomas and asbestosis) following inhalation exposure to asbestos. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2011; 14:76-121. [PMID: 21534086 PMCID: PMC3118517 DOI: 10.1080/10937404.2011.556047] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Lung carcinomas and pulmonary fibrosis (asbestosis) occur in asbestos workers. Understanding the pathogenesis of these diseases is complicated because of potential confounding factors, such as smoking, which is not a risk factor in mesothelioma. The modes of action (MOA) of various types of asbestos in the development of lung cancers, asbestosis, and mesotheliomas appear to be different. Moreover, asbestos fibers may act differentially at various stages of these diseases, and have different potencies as compared to other naturally occurring and synthetic fibers. This literature review describes patterns of deposition and retention of various types of asbestos and other fibers after inhalation, methods of translocation within the lung, and dissolution of various fiber types in lung compartments and cells in vitro. Comprehensive dose-response studies at fiber concentrations inhaled by humans as well as bivariate size distributions (lengths and widths), types, and sources of fibers are rarely defined in published studies and are needed. Species-specific responses may occur. Mechanistic studies have some of these limitations, but have suggested that changes in gene expression (either fiber-catalyzed directly or by cell elaboration of oxidants), epigenetic changes, and receptor-mediated or other intracellular signaling cascades may play roles in various stages of the development of lung cancers or asbestosis.
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Affiliation(s)
- Brooke T Mossman
- Department of Pathology, University of Vermont College of Medicine, Burlington, Vermont 05405, USA.
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Bellmann B, Schaeffer HA, Muhle H. Impact of variations in the chemical composition of vitreous mineral fibers on biopersistence in rat lungs and consequences for regulation. Inhal Toxicol 2010; 22:817-27. [DOI: 10.3109/08958378.2010.483771] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Ikegami T, Tanaka A, Taniguchi M, Clark M, Ragan H, Mast T, Lee K. Chronic Inhalation Toxicity and Carcinogenicity Study on Potassium Octatitanate Fibers (TISMO) in Rats. Inhal Toxicol 2008; 16:291-310. [PMID: 15371181 DOI: 10.1080/08958370490428391] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A chronic inhalation toxicity/carcinogenicity study of potassium octatitanate fibers (TISMO) was conducted in male Fischer 344 rats. Groups of 135 rats were exposed via whole-body inhalation to 0, 20, 60, or 200 WHO fibers/cc of TISMO, 6 h/day, 5 days/w for 24 mo. Six of 30 subgroup rats were killed after 3, 6, 12, 18, and 24 mo of exposure for lung burden evaluations. Another 30 subgroup rats were removed from the exposure chambers after 6 mo of exposure, placed in clean air, and from this group 6 rats were killed at 3, 6, 9, 12, and 18 mo later to study lung clearance. The remaining 75 rats in each group were subjected to 24 mo of exposure for chronic toxicity and carcinogenicity study. Rats exposed to HEPA-filtered air (chamber control) were used as a negative control in each study. The lung burden results indicated that a time point of equilibrium between lung burden and lung clearance at 20 WHO fibers/cc exposure was attained after approximately 18 mo of exposure. There was no difference in the number of WHO fiber from the lungs between 18 and 24 mo at 20 WHO fibers/cc exposure. But disproportional rapid increase in lung burden at 200 WHO fibers/cc exposure appeared to be saturation of lung clearance mechanism resulting from lung overloading. At 200 WHO fibers/cc exposure, approximately 22.9 and 70.5 million WHO fibers were retained in the lung after 3 and 6 mo of exposure, respectively, but lungs revealed normal in appearance. However, alveolar walls enclosing aggregated TISMO-laden alveolar macrophages (AMs) showed fibrotic thickening and approximately 197.3 million WHO fibers were retained in the lungs after 18 mo of exposure. Inhaled fibers were rapidly cleared during 3- and 6-mo recovery periods, and thereafter gradually progressive fiber reduction was observed throughout 18 mo of recovery. The number of WHO fibers decreased by approximately 72%, 74%, and 79% in the 200, 60, and 20 WHO fibers/cc groups, respectively, at the end of the 18-mo recovery period following 6 mo of exposure. Although inhaled TISMO fibers in the 20 WHO fibers/cc exposure group were phagocytized by alveolar macrophages (AMs) the lung morphology appeared normal throughout 24 mo of exposure. At 60 WHO fibers/cc exposure, a slight dose- and time-dependent increase in TISMO-laden AMs was observed throughout 3, 6, and 12 mo of exposure and some alveoli containing aggregated TISMO-laden AMs showed alveolar wall thickening at 18 mo of exposure and minimal alveolar fibrosis at 24 mo of exposure. The exposure concentration is interpreted as a borderline effect level. At 200 WHO fibers/cc exposure, lungs preserved normal architecture at 3 and 6 mo of exposure. Some alveolar walls enclosing aggregates of TISMO-laden AMs were slightly thickened after 12 mo of exposure and revealed slight alveolar fibrosis after 18 and 24 mo of exposure. Neither exposure related-pulmonary neoplasm nor mesothelioma was observed in 24 mo of exposure. The 20 WHO fibers/cc exposure concentration is considered to be a no-observable-adverse-effect level (NOAEL). TISMO exposure limits of 1 WHO fiber/cc would not impose a significant health hazard to humans in the workplace based on the animal experiments and medical surveys on workers.
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Abstract
In 1999 Berry published a model for mesothelioma incidence following fiber exposure. He concluded, that the influence of the solubility of fibers on the mesothelioma rate is 17 times higher in humans than in rats. This conclusion may be helpful for evaluating the carcinogenic risk from man-made vitreous fibers, but it had little influence on some recent discussions. It has been demonstrated using this model, that in an injection experiment with rats, fibers with elimination constants of 0.1/year and 1/year--which would approximately correspond to crocidolite and perhaps ceramic fibers--differ in their mesothelioma risk only by a ratio of 3.2:1. In contrast, for humans exposed continuously from age 20 to age 60 a risk ratio of 4,750:1 is obtained. This result may be helpful for the assessment of the human cancer risk e.g., from exposure to refractory ceramic fibers. However, uncertainty is large, since the life-span of rats is too low to measure the elimination rate of bio-persistent fibers sufficiently.
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Affiliation(s)
- Klaus Rödelsperger
- Institut und Poliklinik für Arbeits- und Sozialmedizin der Justus Liebig Universität Giessen, Giessen, Germany.
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Bernstein D, Castranova V, Donaldson K, Fubini B, Hadley J, Hesterberg T, Kane A, Lai D, McConnell EE, Muhle H, Oberdorster G, Olin S, Warheit DB. Testing of Fibrous Particles: Short-Term Assays and Strategies. Inhal Toxicol 2008; 17:497-537. [PMID: 16040559 DOI: 10.1080/08958370591001121] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Wardenbach P, Rödelsperger K, Roller M, Muhle H. Classification of man-made vitreous fibers: Comments on the revaluation by an IARC working group. Regul Toxicol Pharmacol 2005; 43:181-93. [PMID: 16099571 DOI: 10.1016/j.yrtph.2005.06.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Indexed: 11/26/2022]
Abstract
In 2001, an IARC working group revaluated the carcinogenic risks of man-made vitreous fibers (MMVF). Compared with the IARC evaluation in 1987, the overall evaluations of insulation glass wool, rock (stone) wool, and slag wool were changed from Group 2B to Group 3. These changes ensued from an alteration in the evidence for cancer in humans and in experimental animals: Instead of "sufficient," the evidence for cancer in experimental animals is now looked upon as "limited" if there is a carcinogenic response after intraperitoneal injection but not after recently conducted inhalation experiments. For these studies, it is argued that they did properly address the technological limitations of earlier inhalation experiments. For Maxim and McConnell [Maxim L.D., McConnell E.E., 2001. Interspecies comparisons of the toxicity of asbestos and synthetic vitreous fibers: a weight-of-the-evidence approach. Regul. Toxicol. Pharmacol. 33, 319-342], well-conducted inhalation studies are very sensitive and rats may be more sensitive than humans in detecting the carcinogenic potential of MMVF. However, their arguments are highly questionable. The explanations of the IARC working group for preferring the newer inhalation studies are not sufficiently supported by the published data. Having in mind the higher sensitivity of humans compared to rats after inhalation of asbestos, more emphasis should have been given to the carcinogenic response after intraperitoneal injection.
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Affiliation(s)
- P Wardenbach
- Federal Institute for Occupational Safety and Health, Safety and Health with Chemical and Biological Agents, Friedrich-Henkel-Weg 1-25, Dortmund 44149, Germany.
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Muhle H, Mangelsdorf I. Inhalation toxicity of mineral particles: critical appraisal of endpoints and study design. Toxicol Lett 2003; 140-141:223-8. [PMID: 12676469 DOI: 10.1016/s0378-4274(02)00514-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many of the mineral particles that are of concern in regard to lung toxicity are poorly soluble particles (PSPs). They include biopersistent mineral fibers and dusts containing crystalline silica. The preparation of well-defined test particles of respirable size range and their characterization are an essential step that may require more time and effort than the toxicity study itself. For toxicity studies with mineral particles, an investigation of the toxicokinetics is recommended. Such an investigation will yield information that will help to interpret the results if dust overload conditions occur. For mineral particles such as crystalline silica and mineral fibers, an important endpoint is their potential carcinogenicity. The following parameters are important for the design of chronic toxicity studies, and for the prediction of severe chronic effects: lung retention of inhaled materials for assessing the accumulation of particles, persistent inflammation in lungs, persistent proliferation of epithelial lung cells, progressive fibrogenicity, and genotoxicity in the lung cells. These endpoints should indicate whether the materials investigated are of concern in the health effects on exposed humans, and in the effects of the mineral particles for which chronic studies may be required. In addition, this paper focuses on the effects of PSPs combined with fibers, and on the strategies for investigating the potential carcinogenicity of quartz-containing dusts.
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Affiliation(s)
- H Muhle
- Fraunhofer Institute of Toxicology and Experimental Medicine, Nikolai-Fuchs-Str. 1, 30625, Hannover, Germany.
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LeMasters GK, Lockey JE, Yiin JH, Hilbert TJ, Levin LS, Rice CH. Mortality of workers occupationally exposed to refractory ceramic fibers. J Occup Environ Med 2003; 45:440-50. [PMID: 12708148 DOI: 10.1097/01.jom.0000052968.43131.b5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This study was prompted by refractory ceramic fibers (RCF) inhalation studies at high dose levels in animals that demonstrated positive effects for lung fibrosis, mesothelioma, and lung cancer. Current and former male workers employed between 1952 and 2000 at two RCF manufacturing facilities were followed to investigate a possible excess in mortality. The mortality analytic methods included: (1) standardized mortality ratios comparing this cohort to the general and state populations, and (2) a proportional hazards model that relates risk of death to the lifetime cumulative fiber-months/cc exposure among the RCF cohort, adjusted for age at hire and for race. There was no excess mortality related to all deaths, all cancers, or malignancies or diseases of the respiratory system including mesothelioma, but there was a statistically significant association with cancers of the urinary organs SMR = 344.8 (95% CL of 111.6, 805.4). The quality of the data for job history, exposure, and smoking history were very high. Although the cohort was relatively small and young with an average age of 51, the mean latency period was over 21 years. Because of these limitations, the preliminary findings warrant the continuation of this mortality registry for future analyses.
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Affiliation(s)
- Grace Kawas LeMasters
- Department of Environmental Health, Division of Epidemiology and Biostatistics, University of Cincinnati College of Medicine, 3223 Eden Ave., Kettering Building, ML 0056, Cincinnati, OH 45267-0056, USA.
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