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Hartwig A, Arand M, Epe B, Guth S, Jahnke G, Lampen A, Martus HJ, Monien B, Rietjens IMCM, Schmitz-Spanke S, Schriever-Schwemmer G, Steinberg P, Eisenbrand G. Mode of action-based risk assessment of genotoxic carcinogens. Arch Toxicol 2020; 94:1787-1877. [PMID: 32542409 PMCID: PMC7303094 DOI: 10.1007/s00204-020-02733-2] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 12/16/2022]
Abstract
The risk assessment of chemical carcinogens is one major task in toxicology. Even though exposure has been mitigated effectively during the last decades, low levels of carcinogenic substances in food and at the workplace are still present and often not completely avoidable. The distinction between genotoxic and non-genotoxic carcinogens has traditionally been regarded as particularly relevant for risk assessment, with the assumption of the existence of no-effect concentrations (threshold levels) in case of the latter group. In contrast, genotoxic carcinogens, their metabolic precursors and DNA reactive metabolites are considered to represent risk factors at all concentrations since even one or a few DNA lesions may in principle result in mutations and, thus, increase tumour risk. Within the current document, an updated risk evaluation for genotoxic carcinogens is proposed, based on mechanistic knowledge regarding the substance (group) under investigation, and taking into account recent improvements in analytical techniques used to quantify DNA lesions and mutations as well as "omics" approaches. Furthermore, wherever possible and appropriate, special attention is given to the integration of background levels of the same or comparable DNA lesions. Within part A, fundamental considerations highlight the terms hazard and risk with respect to DNA reactivity of genotoxic agents, as compared to non-genotoxic agents. Also, current methodologies used in genetic toxicology as well as in dosimetry of exposure are described. Special focus is given on the elucidation of modes of action (MOA) and on the relation between DNA damage and cancer risk. Part B addresses specific examples of genotoxic carcinogens, including those humans are exposed to exogenously and endogenously, such as formaldehyde, acetaldehyde and the corresponding alcohols as well as some alkylating agents, ethylene oxide, and acrylamide, but also examples resulting from exogenous sources like aflatoxin B1, allylalkoxybenzenes, 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx), benzo[a]pyrene and pyrrolizidine alkaloids. Additionally, special attention is given to some carcinogenic metal compounds, which are considered indirect genotoxins, by accelerating mutagenicity via interactions with the cellular response to DNA damage even at low exposure conditions. Part C finally encompasses conclusions and perspectives, suggesting a refined strategy for the assessment of the carcinogenic risk associated with an exposure to genotoxic compounds and addressing research needs.
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Affiliation(s)
- Andrea Hartwig
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany.
| | - Michael Arand
- Institute of Pharmacology and Toxicology, University of Zurich, 8057, Zurich, Switzerland
| | - Bernd Epe
- Institute of Pharmacy and Biochemistry, University of Mainz, 55099, Mainz, Germany
| | - Sabine Guth
- Department of Toxicology, IfADo-Leibniz Research Centre for Working Environment and Human Factors, TU Dortmund, Ardeystr. 67, 44139, Dortmund, Germany
| | - Gunnar Jahnke
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany
| | - Alfonso Lampen
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), 10589, Berlin, Germany
| | - Hans-Jörg Martus
- Novartis Institutes for BioMedical Research, 4002, Basel, Switzerland
| | - Bernhard Monien
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), 10589, Berlin, Germany
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Simone Schmitz-Spanke
- Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, University of Erlangen-Nuremberg, Henkestr. 9-11, 91054, Erlangen, Germany
| | - Gerlinde Schriever-Schwemmer
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany
| | - Pablo Steinberg
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Haid-und-Neu-Str. 9, 76131, Karlsruhe, Germany
| | - Gerhard Eisenbrand
- Retired Senior Professor for Food Chemistry and Toxicology, Kühler Grund 48/1, 69126, Heidelberg, Germany.
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Hubacek J, Jirsa M, Bobak M, Pelclova D, Zakharov S. Aldehyde dehydrogenase 2 polymorphism affects the outcome of methanol poisoning in exposed humans. Clin Genet 2018; 94:445-449. [DOI: 10.1111/cge.13411] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/20/2018] [Accepted: 06/28/2018] [Indexed: 12/23/2022]
Affiliation(s)
- J.A. Hubacek
- Center for Experimental Medicine, Institute for Clinical and Experimental Medicine; Prague Czech Republic
| | - M. Jirsa
- Center for Experimental Medicine, Institute for Clinical and Experimental Medicine; Prague Czech Republic
| | - M. Bobak
- International Institute for Health and Society, Department of Epidemiology and Public Health; University College London; London UK
| | - D. Pelclova
- Toxicological Information Center, Department of Occupational Medicine, First Faculty of Medicine; Charles University and General University Hospital in Prague; Prague Czech Republic
| | - S. Zakharov
- Toxicological Information Center, Department of Occupational Medicine, First Faculty of Medicine; Charles University and General University Hospital in Prague; Prague Czech Republic
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Nielsen GD, Larsen ST, Wolkoff P. Re-evaluation of the WHO (2010) formaldehyde indoor air quality guideline for cancer risk assessment. Arch Toxicol 2017; 91:35-61. [PMID: 27209488 PMCID: PMC5225186 DOI: 10.1007/s00204-016-1733-8] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 04/27/2016] [Indexed: 11/11/2022]
Abstract
In 2010, the World Health Organization (WHO) established an indoor air quality guideline for short- and long-term exposures to formaldehyde (FA) of 0.1 mg/m3 (0.08 ppm) for all 30-min periods at lifelong exposure. This guideline was supported by studies from 2010 to 2013. Since 2013, new key studies have been published and key cancer cohorts have been updated, which we have evaluated and compared with the WHO guideline. FA is genotoxic, causing DNA adduct formation, and has a clastogenic effect; exposure-response relationships were nonlinear. Relevant genetic polymorphisms were not identified. Normal indoor air FA concentrations do not pass beyond the respiratory epithelium, and therefore FA's direct effects are limited to portal-of-entry effects. However, systemic effects have been observed in rats and mice, which may be due to secondary effects as airway inflammation and (sensory) irritation of eyes and the upper airways, which inter alia decreases respiratory ventilation. Both secondary effects are prevented at the guideline level. Nasopharyngeal cancer and leukaemia were observed inconsistently among studies; new updates of the US National Cancer Institute (NCI) cohort confirmed that the relative risk was not increased with mean FA exposures below 1 ppm and peak exposures below 4 ppm. Hodgkin's lymphoma, not observed in the other studies reviewed and not considered FA dependent, was increased in the NCI cohort at a mean concentration ≥0.6 mg/m3 and at peak exposures ≥2.5 mg/m3; both levels are above the WHO guideline. Overall, the credibility of the WHO guideline has not been challenged by new studies.
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Affiliation(s)
- Gunnar Damgård Nielsen
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100, Copenhagen, Denmark.
| | - Søren Thor Larsen
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100, Copenhagen, Denmark
| | - Peder Wolkoff
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100, Copenhagen, Denmark
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Dorokhov YL, Shindyapina AV, Sheshukova EV, Komarova TV. Metabolic methanol: molecular pathways and physiological roles. Physiol Rev 2015; 95:603-44. [PMID: 25834233 DOI: 10.1152/physrev.00034.2014] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Methanol has been historically considered an exogenous product that leads only to pathological changes in the human body when consumed. However, in normal, healthy individuals, methanol and its short-lived oxidized product, formaldehyde, are naturally occurring compounds whose functions and origins have received limited attention. There are several sources of human physiological methanol. Fruits, vegetables, and alcoholic beverages are likely the main sources of exogenous methanol in the healthy human body. Metabolic methanol may occur as a result of fermentation by gut bacteria and metabolic processes involving S-adenosyl methionine. Regardless of its source, low levels of methanol in the body are maintained by physiological and metabolic clearance mechanisms. Although human blood contains small amounts of methanol and formaldehyde, the content of these molecules increases sharply after receiving even methanol-free ethanol, indicating an endogenous source of the metabolic methanol present at low levels in the blood regulated by a cluster of genes. Recent studies of the pathogenesis of neurological disorders indicate metabolic formaldehyde as a putative causative agent. The detection of increased formaldehyde content in the blood of both neurological patients and the elderly indicates the important role of genetic and biochemical mechanisms of maintaining low levels of methanol and formaldehyde.
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Affiliation(s)
- Yuri L Dorokhov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia; and N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
| | - Anastasia V Shindyapina
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia; and N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
| | - Ekaterina V Sheshukova
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia; and N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
| | - Tatiana V Komarova
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia; and N. I. Vavilov Institute of General Genetics, Russian Academy of Science, Moscow, Russia
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Peteffi GP, da Silva LB, Antunes MV, Wilhelm C, Valandro ET, Glaeser J, Kaefer D, Linden R. Evaluation of genotoxicity in workers exposed to low levels of formaldehyde in a furniture manufacturing facility. Toxicol Ind Health 2015; 32:1763-73. [PMID: 25971585 DOI: 10.1177/0748233715584250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Formaldehyde (FA) is a chemical widely used in the furniture industry and has been classified as a potential human carcinogen. The purpose of this study was to evaluate the occupational exposure of workers to FA at a furniture manufacturing facility and the relationship between environmental concentrations of FA, formic acid concentration in urine, and DNA damage. The sample consisted of 46 workers exposed to FA and a control group of 45 individuals with no history of occupational exposure. Environmental concentrations of FA were determined by high-performance liquid chromatography. Urinary formic acid concentrations were determined by gas chromatography with flame ionization detector. DNA damage was evaluated by the micronucleus (MN) test performed in exfoliated buccal cells and comet assay with venous blood. The 8-h time-weighted average of FA environmental concentration ranged from 0.03 ppm to 0.09 ppm at the plant, and the control group was exposed to a mean concentration of 0.012 ppm. Workers exposed to higher environmental FA concentrations had urinary formic acid concentrations significantly different from those of controls (31.85 mg L(-1) vs. 19.35 mg L(-), p ≤ 0.01 Mann-Whitney test). Significant differences were found between control and exposed groups for the following parameters: damage frequency and damage index in the comet assay, frequency of binucleated cells in the MN test, and formic acid concentration in urine. The frequency of micronuclei, nuclear buds, and karyorrhexis did not differ between groups. There was a positive correlation between environmental concentrations of FA and damage frequency (Spearman's rank correlation coefficient [r s] = 0.24), damage index (r s = 0.21), binucleated cells (r s = 0.34), and urinary formic acid concentration (r s = 0.63). The results indicate that, although workers in the furniture manufacturing facility were exposed to low environmental levels of FA, this agent contributes to the observed increase in cytogenetic damage. In addition, urinary formic acid concentrations correlated strongly with occupational exposure to FA.
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Affiliation(s)
- Giovana Piva Peteffi
- Laboratory of Toxicological Analysis, Institute of Health Sciences, Universidade Feevale, Novo Hamburgo, Brazil
| | - Luciano Basso da Silva
- Laboratory of Genetics and Molecular Biology, Institute of Health Sciences, Universidade Feevale, Novo Hamburgo, Brazil
| | - Marina Venzon Antunes
- Laboratory of Toxicological Analysis, Institute of Health Sciences, Universidade Feevale, Novo Hamburgo, Brazil
| | - Camila Wilhelm
- Laboratory of Genetics and Molecular Biology, Institute of Health Sciences, Universidade Feevale, Novo Hamburgo, Brazil
| | - Eduarda Trevizani Valandro
- Laboratory of Genetics and Molecular Biology, Institute of Health Sciences, Universidade Feevale, Novo Hamburgo, Brazil
| | - Jéssica Glaeser
- Laboratory of Genetics and Molecular Biology, Institute of Health Sciences, Universidade Feevale, Novo Hamburgo, Brazil
| | - Djeine Kaefer
- Laboratory of Genetics and Molecular Biology, Institute of Health Sciences, Universidade Feevale, Novo Hamburgo, Brazil
| | - Rafael Linden
- Laboratory of Toxicological Analysis, Institute of Health Sciences, Universidade Feevale, Novo Hamburgo, Brazil
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Ke YJ, Qin XD, Zhang YC, Li H, Li R, Yuan JL, Yang X, Ding SM. In vitro study on cytotoxicity and intracellular formaldehyde concentration changes after exposure to formaldehyde and its derivatives. Hum Exp Toxicol 2013; 33:822-30. [DOI: 10.1177/0960327113510538] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
HeLa cells were exposed to formaldehyde and its metabolic derivatives, methanol, formic acid, and acetaldehyde, to investigate that the toxicity of formaldehyde is not caused by the chemical group. After 1 h of treatment with formaldehyde, mitochondrial assays showed that low concentrations (e.g. 10 μmol/L) of formaldehyde promoted growth of the HeLa cells, while higher concentrations (e.g. ≥62.5 μmol/L) inhibited cell growth; while all four chemicals at a concentration of 125 μmol/L affected cell growth, formaldehyde affected the largest. Reactive oxygen species concentration increased with the concentration of the exposure chemical. The endogenous formaldehyde content increased the most in the formaldehyde group, but in other three groups, it did not increase as the exposure concentration increased. Expression of dehydrogenase (formaldehyde dehydrogenase (FDH)) in the formaldehyde (10.40) and methanol (10.60) groups increased significantly compared with the control (1), while it was similar to the control in formic acid (0.90) and acetaldehyde (1.10) groups. Our results suggest that formaldehyde could affect cell activity and even enter cells. Exposure to formaldehyde changes the endogenous formaldehyde concentration in cells within 24 h, and this induces expression of FDH for formaldehyde degradation to maintain the formaldehyde balance. The toxicity of formaldehyde is not caused by the carbon atoms in the aldehyde, hydroxyl, or carboxyl groups. Formaldehyde is hypothesized to be an important signaling molecule in the regulation of cell growth and maintenance of the endogenous formaldehyde level.
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Affiliation(s)
- YJ Ke
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan, People’s Republic of China
| | - XD Qin
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan, People’s Republic of China
| | - YC Zhang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan, People’s Republic of China
| | - H Li
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan, People’s Republic of China
| | - R Li
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan, People’s Republic of China
| | - JL Yuan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan, People’s Republic of China
| | - X Yang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan, People’s Republic of China
| | - SM Ding
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan, People’s Republic of China
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Mitkus RJ, Hess MA, Schwartz SL. Pharmacokinetic modeling as an approach to assessing the safety of residual formaldehyde in infant vaccines. Vaccine 2013; 31:2738-43. [PMID: 23583892 DOI: 10.1016/j.vaccine.2013.03.071] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 03/05/2013] [Accepted: 03/31/2013] [Indexed: 02/08/2023]
Abstract
Formaldehyde is a one-carbon, highly water-soluble aldehyde that is used in certain vaccines to inactivate viruses and to detoxify bacterial toxins. As part of the manufacturing process, some residual formaldehyde can remain behind in vaccines at levels less than or equal to 0.02%. Environmental and occupational exposure, principally by inhalation, is a continuing risk assessment focus for formaldehyde. However, exposure to formaldehyde via vaccine administration is qualitatively and quantitatively different from environmental or occupational settings and calls for a different perspective and approach to risk assessment. As part of a rigorous and ongoing process of evaluating the safety of biological products throughout their lifecycle at the FDA, we performed an assessment of formaldehyde in infant vaccines, in which estimates of the concentrations of formaldehyde in blood and total body water following exposure to formaldehyde-containing vaccines at a single medical visit were compared with endogenous background levels of formaldehyde in a model 2-month-old infant. Formaldehyde levels were estimated using a physiologically-based pharmacokinetic (PBPK) model of formaldehyde disposition following intramuscular (IM) injection. Model results indicated that following a single dose of 200 μg, formaldehyde is essentially completely removed from the site of injection within 30 min. Assuming metabolism at the site of injection only, peak concentrations of formaldehyde in blood/total body water were estimated to be 22 μg/L, which is equivalent to a body burden of 66 μg or <1% of the endogenous level of formaldehyde. Predicted levels in the lymphatics were even lower. Assuming no adverse effects from endogenous formaldehyde, which exists in blood and extravascular water at background concentrations of 0.1 mM, we conclude that residual, exogenously applied formaldehyde continues to be safe following incidental exposures from infant vaccines.
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Affiliation(s)
- Robert J Mitkus
- Office of Biostatistics and Epidemiology, USFDA Center for Biologics Evaluation and Research, 1401 Rockville Pike, HFM-210, Rockville, MD 20852, USA.
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Ladeira C, Viegas S, Carolino E, Gomes MC, Brito M. The influence of genetic polymorphisms in XRCC3 and ADH5 genes on the frequency of genotoxicity biomarkers in workers exposed to formaldehyde. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2013; 54:213-221. [PMID: 23355119 DOI: 10.1002/em.21755] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 11/08/2012] [Accepted: 11/14/2012] [Indexed: 06/01/2023]
Abstract
The International Agency for Research on Cancer classified formaldehyde as carcinogenic to humans because there is "sufficient epidemiological evidence that it causes nasopharyngeal cancer in humans". Genes involved in DNA repair and maintenance of genome integrity are critically involved in protecting against mutations that lead to cancer and/or inherited genetic disease. Association studies have recently provided evidence for a link between DNA repair polymorphisms and micronucleus (MN) induction. We used the cytokinesis-block micronucleus (CBMN assay) in peripheral lymphocytes and MN test in buccal cells to investigate the effects of XRCC3 Thr241Met, ADH5 Val309Ile, and Asp353Glu polymorphisms on the frequency of genotoxicity biomarkers in individuals occupationally exposed to formaldehyde (n = 54) and unexposed workers (n = 82). XRCC3 participates in DNA double-strand break/recombination repair, while ADH5 is an important component of cellular metabolism for the elimination of formaldehyde. Exposed workers had significantly higher frequencies (P < 0.01) than controls for all genotoxicity biomarkers evaluated in this study. Moreover, there were significant associations between XRCC3 genotypes and nuclear buds, namely XRCC3 Met/Met (OR = 3.975, CI 1.053-14.998, P = 0.042) and XRCC3 Thr/Met (OR = 5.632, CI 1.673-18.961, P = 0.005) in comparison with XRCC3 Thr/Thr. ADH5 polymorphisms did not show significant effects. This study highlights the importance of integrating genotoxicity biomarkers and genetic polymorphisms in human biomonitoring studies.
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Affiliation(s)
- Carina Ladeira
- Escola Superior de Tecnologia da Saúde de Lisboa - Instituto Politécnico de Lisboa, Portugal.
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Nielsen GD, Larsen ST, Wolkoff P. Recent trend in risk assessment of formaldehyde exposures from indoor air. Arch Toxicol 2013; 87:73-98. [PMID: 23179754 PMCID: PMC3618407 DOI: 10.1007/s00204-012-0975-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 10/31/2012] [Indexed: 01/09/2023]
Abstract
Studies about formaldehyde (FA) published since the guideline of 0.1 mg/m(3) by the World Health Organization (WHO) in 2010 have been evaluated; critical effects were eye and nasal (portal-of-entry) irritation. Also, it was considered to prevent long-term effects, including all types of cancer. The majority of the recent toxicokinetic studies showed no exposure-dependent FA-DNA adducts outside the portal-of-entry area and FA-DNA adducts at distant sites were due to endogenously generated FA. The no-observed-adverse-effect level for sensory irritation was 0.5 ppm and recently reconfirmed in hypo- and hypersensitive individuals. Investigation of the relationship between FA exposure and asthma or other airway effects in children showed no convincing association. In rats, repeated exposures showed no point mutation in the p53 and K-Ras genes at ≤15 ppm neither increased cell proliferation, histopathological changes and changes in gene expression at 0.7 ppm. Repeated controlled exposures (0.5 ppm with peaks at 1 ppm) did not increase micronucleus formation in human buccal cells or nasal tissue (0.7 ppm) or in vivo genotoxicity in peripheral blood lymphocytes (0.7 ppm), but higher occupational exposures were associated with genotoxicity in buccal cells and cultivated peripheral blood lymphocytes. It is still valid that exposures not inducing nasal squamous cell carcinoma in rats will not induce nasopharyngeal cancer or lymphohematopoietic malignancies in humans. Reproductive and developmental toxicity are not considered relevant in the absence of sensory irritation. In conclusion, the WHO guideline has been strengthened.
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Affiliation(s)
- Gunnar Damgård Nielsen
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen, Denmark.
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Zeller J, Högel J, Linsenmeyer R, Teller C, Speit G. Investigations of potential susceptibility toward formaldehyde-induced genotoxicity. Arch Toxicol 2012; 86:1465-73. [PMID: 22411273 DOI: 10.1007/s00204-012-0830-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 02/27/2012] [Indexed: 01/07/2023]
Abstract
Blood samples were taken from three groups of volunteers (30 male smokers, 30 female non-smokers, and 30 school children) and tested for ex vivo susceptibility toward formaldehyde (FA)-induced genotoxicity. Blood samples were exposed to 150 μM FA for 2 h, and the induction of DNA-protein crosslinks (DPX) in leukocytes was measured by a modification of the alkaline comet assay (i.e., reduction of γ-irradiation induced DNA migration). Removal of DPX was determined by the abolition of FA-induced reduction in DNA migration within 4 h after the end of the exposure. Induction and persistence of FA-induced DNA lesions was also measured by the sister chromatid exchange (SCE) test with cultured lymphocytes after treatment of whole blood cultures with FA (150 μM). Furthermore, the expression (mRNA level) of the GSH-dependent formaldehyde dehydrogenase (FDH, identical to alcohol dehydrogenase 5; ADH5) was measured in leukocytes by quantitative real-time RT-PCR with TaqMan probes. The subjects were also analyzed for the GSTM1 and GSTT1 metabolic gene polymorphisms and a correlation analysis with the investigated genetic endpoints for FA-induced genotoxicity was performed. The results indicate that there are no biologically relevant differences between the three study groups with regard to the various indicators of cellular sensitivity toward FA-induced genotoxic effects and the expression of FDH. The induced genotoxic effects were not associated with polymorphisms in GSTM1 and GSTT1. None of the study groups showed particular mutagen sensitivity toward FA-induced genotoxicity. These results suggest that a low scaling factor to address possible human inter-individual differences in FA-induced genotoxicity could be reasonable.
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Affiliation(s)
- Jasmin Zeller
- Institut für Humangenetik, Universität Ulm, 89069 Ulm, Germany
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