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Galli Rapporteur CL, Bernauer U, Bodin L, Chaudhry Q, Coenraads PJ, Dusinska M, Ezendam J, Granum B, Gaffet E, Panteri E, Rogiers V, Rousselle C, Stepnik M, Vanhaecke T, Wijnhoven S, Koutsodimou A, Uter W, von Goetz N. SCCS Scientific Opinion on Acid Yellow 3 (submission II) - SCCS/1631/21. Regul Toxicol Pharmacol 2023; 140:105364. [PMID: 36907371 DOI: 10.1016/j.yrtph.2023.105364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/01/2023] [Accepted: 02/15/2023] [Indexed: 03/12/2023]
Abstract
Opinion to be cited as: SCCS (Scientific Committee on Consumer Safety), Opinion on Acid Yellow 3 - C054 (CAS Number 8004-92-0, EC No 305-897-5), submission II, preliminary version of 7 May 2021, final version of 23 July 2021, SCCS/1631/21.
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Affiliation(s)
| | | | - Ulrike Bernauer
- Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Laurent Bodin
- Alternative Energies and Atomic Energy Commission (CEA), Saclay, France
| | | | | | - Maria Dusinska
- Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Janine Ezendam
- National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Berit Granum
- Norwegian Institute of Public Health, Oslo, Norway
| | - Eric Gaffet
- Institute Jean Lamour (UMR 7198 CNRS - Université de Lorraine), Nancy, France
| | - Eirini Panteri
- National and Kapodistrian University of Athens, School of Pharmacy, Division of Pharmaceutical Chemistry, Athens, Greece
| | | | - Christophe Rousselle
- French Agency for Food, Environmental and Occupational Health & Safety (ANSES), International and European Affairs Department, France
| | | | | | - Susan Wijnhoven
- RIVM, Centre for Safety of Substances and Products (VSP), Centre for Substances and Integrated Risk Assessment (SIR), Bilthoven, the Netherlands
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Granum Rapporteur B, Bernauer U, Bodin L, Chaudhry Q, Pieter Jan C, Dusinska M, Ezendam J, Gaffet E, Galli CL, Panteri E, Rogiers V, Rousselle C, Stepnik M, Vanhaecke T, Wijnhoven S, Koutsodimou A, Uter W, von Goetz N. SCCS scientific opinion on Butylated hydroxytoluene (BHT) - SCCS/1636/21. Regul Toxicol Pharmacol 2023; 138:105312. [PMID: 36565917 DOI: 10.1016/j.yrtph.2022.105312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022]
Abstract
OPINION TO BE CITED AS SCCS (Scientific Committee on Consumer Safety), scientific opinion on Butylated hydroxytoluene (BHT), preliminary version of September 27, 2021, final version of December 2, 2021, SCCS/1636/21.
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Affiliation(s)
| | | | - Ulrike Bernauer
- Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Laurent Bodin
- Alternative Energies and Atomic Energy Commission (CEA), Saclay, France
| | - Qasim Chaudhry
- Institute of Food Science & Innovation, University of Chester, United Kingdom
| | | | - Maria Dusinska
- Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Janine Ezendam
- National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Eric Gaffet
- Institute Jean Lamour (UMR 7198 CNRS - Université de Lorraine), Nancy, France
| | - Corrado L Galli
- Faculty of Pharmaceutical Sciences University of Milan, Italy
| | - Eirini Panteri
- National and Kapodistrian University of Athens, School of Pharmacy, Division of Pharmaceutical Chemistry, Athens, Greece
| | - Vera Rogiers
- Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Christophe Rousselle
- French Agency for Food, Environmental and Occupational Health & Safety (ANSES), International and European Affairs Department, France
| | | | | | - Susan Wijnhoven
- RIVM, Centre for Safety of Substances and Products (VSP), Centre for Substances and Integrated Risk Assessment (SIR), Bilthoven, the Netherlands
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Bernauer U, Bodin L, Chaudhry Q, Coenraads PJ, Dusinska M, Gaffet E, Panteri E, Rogiers V, Rousselle C, Stepnik M, Vanhaecke T, Wijnhoven S, von Goetz N, de Jong WH. The SCCS scientific advice on the safety of nanomaterials in cosmetics. Regul Toxicol Pharmacol 2021; 126:105046. [PMID: 34560169 DOI: 10.1016/j.yrtph.2021.105046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 09/06/2021] [Indexed: 10/20/2022]
Abstract
The Cosmetic Regulation (EC) No 1223/2009 specifically covers the risk of nanomaterials used in cosmetic products. If there are concerns regarding the safety of a nanomaterial, the European Commission refers it to the SCCS for a scientific opinion. The Commission mandated the SCCS to identify the scientific basis for safety concerns that could be used as a basis for identifying and prioritising nanomaterials for safety assessment, and to revisit previous inconclusive SCCS opinions on nanomaterials to identify any concerns for potential risks to the consumer health. The SCCS Scientific Advice identified the key general aspects of nanomaterials that should raise a safety concern for a safety assessor/manager, so that the nanomaterial(s) in question could be subjected to safety assessment to establish safety to the consumer. The Advice also developed a list of the nanomaterials notified to the Commission for use in cosmetics in an order of priority for safety assessment, and revisited three previous inconclusive opinions on nanomaterials to highlight concerns over consumer safety that merited further safety assessment.
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Affiliation(s)
| | - Ulrike Bernauer
- Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Laurent Bodin
- Alternative Energies and Atomic Energy Commission (CEA), Saclay, France
| | | | | | - Maria Dusinska
- Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Eric Gaffet
- Institute Jean Lamour (UMR 7198 CNRS Université de Lorraine), Nancy, France
| | - Eirini Panteri
- National and Kapodistrian University of Athens, School of Pharmacy, Division of Pharmaceutical Chemistry, Athens, Greece
| | | | - Christophe Rousselle
- French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Maisons-Alfort, France
| | | | | | - Susan Wijnhoven
- National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | | | | | - Wim H de Jong
- Formerly Centre for Health Protection, National Institute for Public Health (RIVM), Bilthoven, the Netherlands
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Rogiers V, Benfenati E, Bernauer U, Bodin L, Carmichael P, Chaudhry Q, Coenraads PJ, Cronin MT, Dent M, Dusinska M, Ellison C, Ezendam J, Gaffet E, Galli CL, Goebel C, Granum B, Hollnagel HM, Kern PS, Kosemund-Meynen K, Ouédraogo G, Panteri E, Rousselle C, Stepnik M, Vanhaecke T, von Goetz N, Worth A. The way forward for assessing the human health safety of cosmetics in the EU - Workshop proceedings. Toxicology 2020; 436:152421. [DOI: 10.1016/j.tox.2020.152421] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/21/2020] [Accepted: 02/25/2020] [Indexed: 12/20/2022]
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5
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Bernauer U, Bodin L, Chaudhry Q, Coenraads P, Dusinska M, Ezendam J, Gaffet E, Galli CL, Granum BB, Panteri E, Rogiers V, Rousselle C, Stępnik M, Vanhaecke T, Wijnhoven S, Koutsodimou A, Simonnard A, Uter W. Opinion of the Scientific Committee on consumer safety (SCCS) – Final opinion on the safety of fragrance ingredient Acetylated Vetiver Oil (AVO) - (Vetiveria zizanioides root extract acetylated) - Submission III. Regul Toxicol Pharmacol 2019; 107:104389. [DOI: 10.1016/j.yrtph.2019.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/08/2019] [Accepted: 05/12/2019] [Indexed: 10/26/2022]
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Mech A, Rasmussen K, Jantunen P, Aicher L, Alessandrelli M, Bernauer U, Bleeker EAJ, Bouillard J, Di Prospero Fanghella P, Draisci R, Dusinska M, Encheva G, Flament G, Haase A, Handzhiyski Y, Herzberg F, Huwyler J, Jacobsen NR, Jeliazkov V, Jeliazkova N, Nymark P, Grafström R, Oomen AG, Polci ML, Riebeling C, Sandström J, Shivachev B, Stateva S, Tanasescu S, Tsekovska R, Wallin H, Wilks MF, Zellmer S, Apostolova MD. Insights into possibilities for grouping and read-across for nanomaterials in EU chemicals legislation. Nanotoxicology 2018; 13:119-141. [DOI: 10.1080/17435390.2018.1513092] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- A. Mech
- Directorate F – Health, Consumers and Reference Materials, JRC, European Commission's Joint Research Centre, Ispra, Italy
| | - K. Rasmussen
- Directorate F – Health, Consumers and Reference Materials, JRC, European Commission's Joint Research Centre, Ispra, Italy
| | - P. Jantunen
- Directorate F – Health, Consumers and Reference Materials, JRC, European Commission's Joint Research Centre, Ispra, Italy
| | - L. Aicher
- Department of Pharmaceutical Sciences and Swiss Centre for Applied Human Toxicology (SCAHT), University of Basel, Basel, Switzerland
| | | | - U. Bernauer
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - E. A. J. Bleeker
- National Institute for Public Health and the Environment (RIVM), RIVM, Bilthoven, the Netherlands
| | - J. Bouillard
- Parc Technologique ALATA, INERIS, Verneuil-en-Halatte, France
| | | | - R. Draisci
- Istituto Superiore di Sanità, ISS, Roma, Italy
| | - M. Dusinska
- Norwegian Institute for Air Research, NILU, Kjeller, Norway
| | - G. Encheva
- Institute of Molecular Biology – BAS, IMB-BAS, Sofia, Bulgaria
| | - G. Flament
- Nanotechnology Industries Association, NIA, Woluwe-Saint-Pierre, Brussels, Belgium
| | - A. Haase
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Y. Handzhiyski
- Institute of Molecular Biology – BAS, IMB-BAS, Sofia, Bulgaria
| | - F. Herzberg
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - J. Huwyler
- Department of Pharmaceutical Sciences and Swiss Centre for Applied Human Toxicology (SCAHT), University of Basel, Basel, Switzerland
| | - N. R. Jacobsen
- National Research Centre for the Working Environment, NRCWE, Copenhagen, Denmark
| | | | | | - P. Nymark
- Institute for Environmental Medicine, KI, Karolinska Institutet, Stockholm, Sweden
- Toxicology Division, Misvik Biology, Turku, Finland
| | - R. Grafström
- Institute for Environmental Medicine, KI, Karolinska Institutet, Stockholm, Sweden
- Toxicology Division, Misvik Biology, Turku, Finland
| | - A. G. Oomen
- National Institute for Public Health and the Environment (RIVM), RIVM, Bilthoven, the Netherlands
| | - M. L. Polci
- Istituto Superiore di Sanità, ISS, Roma, Italy
| | - C. Riebeling
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - J. Sandström
- Department of Pharmaceutical Sciences and Swiss Centre for Applied Human Toxicology (SCAHT), University of Basel, Basel, Switzerland
| | - B. Shivachev
- Institute of Molecular Biology – BAS, IMB-BAS, Sofia, Bulgaria
| | - S. Stateva
- Institute of Molecular Biology – BAS, IMB-BAS, Sofia, Bulgaria
| | - S. Tanasescu
- Romanian Academy, Institute of Physical Chemistry “Ilie Murgulescu”, IPC, Bucharest, Romania
| | - R. Tsekovska
- Institute of Molecular Biology – BAS, IMB-BAS, Sofia, Bulgaria
| | - H. Wallin
- National Institute of Occupational Health, STAMI, Gydas vei 8, Oslo, 0363, Norway
| | - M. F. Wilks
- Department of Pharmaceutical Sciences and Swiss Centre for Applied Human Toxicology (SCAHT), University of Basel, Basel, Switzerland
| | - S. Zellmer
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
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Bernauer U. Opinion of the Scientific Committee on Consumer Safety (SCCS) - Revision of the Opinion on hydroxyapatite (nano) in cosmetic products. Regul Toxicol Pharmacol 2018; 98:274-275. [PMID: 30125613 DOI: 10.1016/j.yrtph.2018.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 07/22/2018] [Indexed: 10/28/2022]
Abstract
In response to the concerns of the European Commission about potential absorption and entry of nanoparticles of hydroxyapatite into the cells when used in oral cosmetic products, the Scientific Committee on Consumer Safety (SCCS) was requested to provide a safety assessment of hydroxyapatite (nano). After making a detailed evaluation of the data provided in the submissions and scientific literature, the SCCS considered needle-shaped hydroxyapatite (nano) to be of concern due to its potential toxic effects, and stated that it should not be used in cosmetic products. In terms of other shapes of hydroxyapatite (nano), the available evidence was insufficient to allow drawing a conclusion on the safety of hydroxyapatite (nano) when used in oral cosmetic products up to a concentration of 10%.
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Affiliation(s)
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- SCCS Secretariat at the European Commission, Directorate General for Health and Food Safety, 11, rue E. Ruppert, L-2920, Luxembourg, Luxembourg
| | - Ulrike Bernauer
- Federal Institute for Risk Assessment (BfR), Berlin, Germany
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Kronsbein AL, Maul K, Menz J, Oertel A, Sittner D, Springer A, Bernauer U, Herbst U, Schulte A. REACH Compliance Project: Alternative methods to animal testing in REACH registrations on high tonnage chemicals – Data waiving and adaptation. Toxicol Lett 2017. [DOI: 10.1016/j.toxlet.2017.08.078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bernauer U. Opinion of the Scientific Committee on Consumer Safety (SCCS) - Revision of the opinion on o-Phenylphenol, Sodium o-phenylphenate and Potassium o-phenylphenate (OPP), in cosmetic products. Regul Toxicol Pharmacol 2016; 79:105. [PMID: 26946408 DOI: 10.1016/j.yrtph.2016.02.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 02/28/2016] [Indexed: 11/15/2022]
Abstract
o-Phenylphenol, Sodium o-phenylphenate, Potassium o-phenylphenate, CAS n. 90-43-7, 132-27-4, 13707-65-8 as preservatives are regulated in Annex V/7 of the Cosmetics Regulation (EC) n. 1223/2009 at a maximum concentration of 0.2% (as phenol). In February 2013, the Commission received a risk assessment submitted by the French Agency ANSM (Agence nationale de sécurité des médicaments et des produits de santé) which rose concerns about the use of o-Phenylphenol as preservatives in cosmetic products. In the context of the ANSM report (Evaluation du risque lié à l'utilisation de l'orthophénylphénol CAS n. 90-43-7 dans les produits cosmétiques) o-Phenylphenol has been identified as likely to be an endocrine disruptor. The report concludes that the maximum authorised concentration (currently of 0.2%) of o-Phenylphenol for use as a preservative should be revised due to low margin of safety. In January 2014, in response to a call for data on o-Phenylphenol by the Commission, Industry submitted a safety dossier in order to defend the current use of o-Phenylphenol, Sodium o-phenylphenate, Potassium o-phenylphenate, CAS n. 90-43-7, 132-27-4, 13707- 65-8 as preservatives in cosmetic formulations at a maximum concentration of 0.2% (as phenol). o-Phenylphenol as preservative with a maximum concentration of 0.2% in leave-on cosmetic products is not safe. Also, in view of further exposures including noncosmetic uses (see Anses, 2014), the maximum concentration of o-Phenylphenol in leave-on cosmetic products should be lowered. However, the proposed maximum use concentration of up to 0.15% by the applicant can be considered safe. The use of o-Phenylphenol as preservative with a maximum concentration of 0.2% in rinse-off cosmetic products is considered safe. Based on the information provided, no conclusions of safe use can be drawn for Sodium o-phenylphenate and Potassium o-phenylphenate. In vitro data indicate an absent or very weak binding affinity of OPP to the oestrogen receptor, in line with limited stimulation of proliferation in oestrogen responsive cells. No information is available on androgenic and anti-androgenic effects of OPP in vitro. Agonistic or antagonistic effects on thyroid hormones were not observed with OPP. There might be a potential of injury to the vision system attributable to OPP. Aggregate exposure to OPP should be considered.
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Affiliation(s)
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- Directorate General for Health and Food Safety, 11, rue E. Ruppert, L-2920 Luxembourg, Luxembourg.
| | - Ulrike Bernauer
- Federal Institute for Risk Assessment (BfR), Berlin, Germany
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Testai E, Hartemann P, Rastogi SC, Bernauer U, Piersma A, De Jong W, Gulliksson H, Sharpe R, Schubert D, Rodríguez-Farre E. The safety of medical devices containing DEHP plasticized PVC or other plasticizers on neonates and other groups possibly at risk (2015 update). Regul Toxicol Pharmacol 2016; 76:209-10. [PMID: 26854686 DOI: 10.1016/j.yrtph.2016.01.013] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 11/15/2022]
Affiliation(s)
- Emanuela Testai
- Member of the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR), Luxembourg
| | | | - Philippe Hartemann
- Member of the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR), Luxembourg
| | | | - Ulrike Bernauer
- Member of the Scientific Committee on Consumer Safety (SCCS), Luxembourg
| | | | - Wim De Jong
- Member of the SCENIHR Working Group on DEHP, Luxembourg
| | | | | | - Dirk Schubert
- Member of the SCENIHR Working Group on DEHP, Luxembourg
| | - Eduardo Rodríguez-Farre
- Member of the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR), Luxembourg
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Bernauer U. Opinion of the scientific committee on consumer safety (SCCS) – 2nd Revision of the safety of the use of poly(hexamethylene) biguanide hydrochloride or polyaminopropyl biguanide (PHMB) in cosmetic products. Regul Toxicol Pharmacol 2015; 73:885-6. [DOI: 10.1016/j.yrtph.2015.09.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 09/29/2015] [Indexed: 11/25/2022]
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12
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Bernauer U, Coenraads PJ, Degen GH, Dusinska M, Lilienblum W, Luch A, Nielsen E, Platzek T, Rastogi S, Rousselle C, van Benthem J, Bernard A, Giménez-Arnau AM, Vanhaecke T. Opinion of the Scientific Committee on Consumer Safety (SCCS) – The safety of the use of formaldehyde in nail hardeners. Regul Toxicol Pharmacol 2015; 72:658-9. [DOI: 10.1016/j.yrtph.2015.02.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 02/27/2015] [Accepted: 02/28/2015] [Indexed: 10/23/2022]
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Gundert-Remy U, Bernauer U, Blömeke B, Döring B, Fabian E, Goebel C, Hessel S, Jäckh C, Lampen A, Oesch F, Petzinger E, Völkel W, Roos PH. Extrahepatic metabolism at the body's internal–external interfaces. Drug Metab Rev 2014; 46:291-324. [DOI: 10.3109/03602532.2014.900565] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Bernauer U, Schulte A, Moeder M, Schrader S, Reemtsma T. Asymmetric phthalates—A special case for risk assessment. Toxicol Lett 2013. [DOI: 10.1016/j.toxlet.2013.05.525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Gundert-Remy U, Mielke H, Bernauer U. Commentary: Dermal penetration of bisphenol A—Consequences for risk assessment. Toxicol Lett 2013; 217:159-61. [DOI: 10.1016/j.toxlet.2012.12.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 12/11/2012] [Accepted: 12/12/2012] [Indexed: 11/29/2022]
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Coecke S, Pelkonen O, Leite SB, Bernauer U, Bessems JG, Bois FY, Gundert-Remy U, Loizou G, Testai E, Zaldívar JM. Toxicokinetics as a key to the integrated toxicity risk assessment based primarily on non-animal approaches. Toxicol In Vitro 2012; 27:1570-7. [PMID: 22771339 DOI: 10.1016/j.tiv.2012.06.012] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 03/09/2012] [Accepted: 06/22/2012] [Indexed: 02/02/2023]
Abstract
Toxicokinetics (TK) is the endpoint that informs about the penetration into and fate within the body of a toxic substance, including the possible emergence of metabolites. Traditionally, the data needed to understand those phenomena have been obtained in vivo. Currently, with a drive towards non-animal testing approaches, TK has been identified as a key element to integrate the results from in silico, in vitro and already available in vivo studies. TK is needed to estimate the range of target organ doses that can be expected from realistic human external exposure scenarios. This information is crucial for determining the dose/concentration range that should be used for in vitro testing. Vice versa, TK is necessary to convert the in vitro results, generated at tissue/cell or sub-cellular level, into dose response or potency information relating to the entire target organism, i.e. the human body (in vitro-in vivo extrapolation, IVIVE). Physiologically based toxicokinetic modelling (PBTK) is currently regarded as the most adequate approach to simulate human TK and extrapolate between in vitro and in vivo contexts. The fact that PBTK models are mechanism-based which allows them to be 'generic' to a certain extent (various extrapolations possible) has been critical for their success so far. The need for high-quality in vitro and in silico data on absorption, distribution, metabolism as well as excretion (ADME) as input for PBTK models to predict human dose-response curves is currently a bottleneck for integrative risk assessment.
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Affiliation(s)
- Sandra Coecke
- ECVAM, Institute for Health & Consumer Protection, European Commission Joint Research Centre, 21027 Ispra (VA), Italy
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Bernauer U, Rosenthal E, Heinrich-Hirsch B, Schulte A. Comparative male reproductive toxicity of selected phthalates. Toxicol Lett 2011. [DOI: 10.1016/j.toxlet.2011.05.844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Adler S, Basketter D, Creton S, Pelkonen O, van Benthem J, Zuang V, Andersen KE, Angers-Loustau A, Aptula A, Bal-Price A, Benfenati E, Bernauer U, Bessems J, Bois FY, Boobis A, Brandon E, Bremer S, Broschard T, Casati S, Coecke S, Corvi R, Cronin M, Daston G, Dekant W, Felter S, Grignard E, Gundert-Remy U, Heinonen T, Kimber I, Kleinjans J, Komulainen H, Kreiling R, Kreysa J, Leite SB, Loizou G, Maxwell G, Mazzatorta P, Munn S, Pfuhler S, Phrakonkham P, Piersma A, Poth A, Prieto P, Repetto G, Rogiers V, Schoeters G, Schwarz M, Serafimova R, Tähti H, Testai E, van Delft J, van Loveren H, Vinken M, Worth A, Zaldivar JM. Alternative (non-animal) methods for cosmetics testing: current status and future prospects-2010. Arch Toxicol 2011; 85:367-485. [PMID: 21533817 DOI: 10.1007/s00204-011-0693-2] [Citation(s) in RCA: 355] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/03/2011] [Indexed: 01/09/2023]
Abstract
The 7th amendment to the EU Cosmetics Directive prohibits to put animal-tested cosmetics on the market in Europe after 2013. In that context, the European Commission invited stakeholder bodies (industry, non-governmental organisations, EU Member States, and the Commission's Scientific Committee on Consumer Safety) to identify scientific experts in five toxicological areas, i.e. toxicokinetics, repeated dose toxicity, carcinogenicity, skin sensitisation, and reproductive toxicity for which the Directive foresees that the 2013 deadline could be further extended in case alternative and validated methods would not be available in time. The selected experts were asked to analyse the status and prospects of alternative methods and to provide a scientifically sound estimate of the time necessary to achieve full replacement of animal testing. In summary, the experts confirmed that it will take at least another 7-9 years for the replacement of the current in vivo animal tests used for the safety assessment of cosmetic ingredients for skin sensitisation. However, the experts were also of the opinion that alternative methods may be able to give hazard information, i.e. to differentiate between sensitisers and non-sensitisers, ahead of 2017. This would, however, not provide the complete picture of what is a safe exposure because the relative potency of a sensitiser would not be known. For toxicokinetics, the timeframe was 5-7 years to develop the models still lacking to predict lung absorption and renal/biliary excretion, and even longer to integrate the methods to fully replace the animal toxicokinetic models. For the systemic toxicological endpoints of repeated dose toxicity, carcinogenicity and reproductive toxicity, the time horizon for full replacement could not be estimated.
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Affiliation(s)
- Sarah Adler
- Centre for Documentation and Evaluation of Alternatives to Animal Experiments (ZEBET), Federal Institute for Risk Assessment (BfR), Berlin, Germany
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Jacobs MN, Janssens W, Bernauer U, Brandon E, Coecke S, Combes R, Edwards P, Freidig A, Freyberger A, Kolanczyk R, Mc Ardle C, Mekenyan O, Schmieder P, Schrader T, Takeyoshi M, van der Burg B. The use of metabolising systems for in vitro testing of endocrine disruptors. Curr Drug Metab 2009; 9:796-826. [PMID: 18855613 DOI: 10.2174/138920008786049294] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Legislation and prospective legislative proposals in for instance the USA, Europe, and Japan require, or may require that chemicals are tested for their ability to disrupt the hormonal systems of mammals. Chemicals found to test positive are considered to be endocrine active substances (EAS) and may be putative endocrine disruptors (EDs). To date, there is still little or no experience with incorporating metabolic and toxicokinetic aspects into in vitro tests for EAS. This is a situation in sharp contrast to genotoxicity testing, where in vitro tests are routinely conducted with and without metabolic capacity. Originally prepared for the Organisation of Economic Cooperation and Development (OECD), this detailed review paper reviews why in vitro assays for EAS should incorporate mammalian systems of metabolism and metabolic enzyme systems, and indicates how this could be done. The background to ED testing, the available test methods, and the role of mammalian metabolism in the activation and the inactivation of both endogenous and exogenous steroids are described. The available types of systems are compared, and the potential problems in incorporating systems in in vitro tests for EAS, and how these might be overcome, are discussed. Lastly, some recommendations for future activities are made.
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Affiliation(s)
- M N Jacobs
- Scientific Institute of Public Health, Belgium.
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Gundert-Remy U, Bernauer U, Madle S, Oberemm A, Schulte A, Richter-Reichhelm HB. Letter to the Editor: A regulatory view on the discussion on the role of alternative methods in the risk assessment of chemicals in the context of REACH. Arch Toxicol 2008; 83:9-10. [DOI: 10.1007/s00204-008-0383-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Accepted: 10/27/2008] [Indexed: 11/28/2022]
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Settels E, Bernauer U, Palavinskas R, Klaffke HS, Gundert-Remy U, Appel KE. Human CYP2E1 mediates the formation of glycidamide from acrylamide. Arch Toxicol 2008; 82:717-27. [DOI: 10.1007/s00204-008-0296-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 03/12/2008] [Indexed: 10/22/2022]
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Bernauer U, Heinemeyer G, Heinrich-Hirsch B, Ulbrich B, Gundert-Remy U. Exposure-triggered reproductive toxicity testing under the REACH legislation: A proposal to define significant/relevant exposure. Toxicol Lett 2008; 176:68-76. [DOI: 10.1016/j.toxlet.2007.10.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 10/19/2007] [Accepted: 10/19/2007] [Indexed: 10/22/2022]
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Bernauer U, Heinrich-Hirsch B, Tönnies M, Peter-Matthias W, Gundert-Remy U. Characterisation of the xenobiotic-metabolizing Cytochrome P450 expression pattern in human lung tissue by immunochemical and activity determination. Toxicol Lett 2006; 164:278-88. [PMID: 16483733 DOI: 10.1016/j.toxlet.2006.01.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2005] [Revised: 01/13/2006] [Accepted: 01/13/2006] [Indexed: 10/25/2022]
Abstract
The lung represents an important target for the toxic effects of chemicals. Many of the chemicals require enzymatic activation to exert their adverse effects, which is mostly catalysed by Cytochrome P450 (CYP) enzymes. Although there is considerable evidence that individual members of the xenobiotic-metabolizing P450 family are expressed in human lung tissue at the mRNA level, there is conflicting evidence concerning the following issues: (I) the qualitative expression pattern of CYP isoenzymes; (II) CYP expression at the protein and/or activity level; and (III) interindividual variability of CYP enzymes in human lung. The latter can be the basis for individual susceptibility towards the adverse effects of lung toxicants. In preparing for studying factors to explain interindividual variability of CYP expression in lung tissue, we investigated the qualitative pulmonary expression pattern of xenobiotic-metabolizing CYP enzymes and elaborated the optimal conditions for quantification at the protein and activity level. By using either individual human lung samples or pooled microsomes from different individuals, immunoreactive bands specific for the following CYP enzymes could be determined by Western blotting: CYP1A1, CYP1A2, CYP2E1 and CYP3A5. Western blotting experiments were also supportive of the presence of CYP2A, CYP2B6, CYP2D6 and CYP3A4 in human lung. By using antibodies specific for CYP2C enzymes and CYP1B1, respectively, immunoreactive bands, which differed slightly in mobility from corresponding standards, were detectable. In addition, we measured methoxy- and ethoxyresorufin dealkylase activities and chlorzoxazone (CLX)-hydroxylase activity in human lung and confirmed the specifities of the latter two activities by inhibition experiments. In summary, we have established methodologies to quantify a panel of CYP enzymes in human lung samples among which there are CYP enzymes whose expression at the protein and activity level has not been evidenced so far.
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Affiliation(s)
- Ulrike Bernauer
- Federal Institute for Risk Assessment/Bundesinstitut für Risikobewertung (BfR), Thielallee 88-92, D-14195 Berlin, Germany.
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Bernauer U, Glatt H, Heinrich-Hirsch B, Liu Y, Muckel E, Vieth B, Gundert-Remy U. Heterologous expression of mouse cytochrome P450 2e1 in V79 cells: construction and characterisation of the cell line and comparison with V79 cell lines stably expressing rat P450 2E1 and human P450 2E1. Altern Lab Anim 2005; 31:21-30. [PMID: 16221041 DOI: 10.1177/026119290303100104] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A V79 Chinese hamster cell line was constructed for stable expression of mouse cytochrome P450 2e1 (Cyp2e1), as an addition to the existing cell battery consisting of cell lines stably expressing rat CYP2E1 and human CYP2E1 (V79 Cell Battery). The aim was to establish a cell battery that offers the in vitro possibility of investigating species-specific differences in the toxicity and metabolism of chemicals representing substrates for CYP2E1. The newly established cell line (V79m2E1) effectively expressed Cyp2e1 in the catalytically active form. The expression of catalytically active CYP2E1 in V79m2E1 cells was maintained over several months in culture, as demonstrated by Western Blotting and chlorzoxazone (CLX) 6-hydroxylase activity. The cells exhibited CLX 6-hydroxylase activity with a Km of 27.8 microM/l and Vmax of 40 pmol/mg protein/minute, compared with a Km of 28.2/28.6 microM/l and a Vmax of 130/60 pmol/mg protein/minute from V79r2E1/V79h2E1 cells. Furthermore, the CYP2E1-dependent mutagenicity of N-nitrosodimethylamine could be demonstrated in the V79m2E1 cells. Therefore, the new cell battery permits the interspecies comparison of CYP2E1-dependent toxicity and of metabolism of chemicals between humans and the two major rodent species--the rat and the mouse--that are usually used in classical toxicity studies.
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Affiliation(s)
- Ulrike Bernauer
- Federal Institute for Risk Assessment (BfR), Thielallee 88-92, 14195 Berlin, Germany
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Abstract
Describing the toxicological profile of a substance is the first step required for risk assessment. Although a wide range of in vitro methods are widely used to characterise toxicological properties including toxicokinetics, regulatory acceptance is mainly confined to in vitro tests which investigate genotoxic end-points. In vitro tests have been proposed for the endpoints acute toxicity, repeated dose toxicity and toxicity to reproduction which encompass the minimum requirements in the OECD SIDS programme. However, until now, limitations of the proposed tests preclude their application in a regulatory framework. Presently, in vitro tests play a major role in obtaining information on mechanism of toxicity with the perspective to be able to identify pathways of toxic responses by applying toxicogenomics techniques. Physiologically based toxicokinetic modelling is using data from in vitro studies to build up the model for a specific compound. Information from both areas is incorporated into the risk assessment to derive compound-specific safety factors, which account for species differences and for the variability among the human population, including possible sensitive subpopulations. Future developments to further enhance the use of in vitro methods in regulatory toxicology include the development of (Q)SAR approaches supplemented by mechanisms of toxicity, which can be addressed by developing methods of molecular toxicology.
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Affiliation(s)
- Ulrike Bernauer
- Federal Institute for Risk Assessment, Thielallee 88-92, D-14195 Berlin, Germany
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Bernauer U, Ellrich R, Heinrich-Hirsch B, Teubner W, Vieth B, Gundert-Remy U. Expression of cytochrome P450 enzymes in human colon. IARC Sci Publ 2003; 156:487-9. [PMID: 12484239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- U Bernauer
- Federal Institute for Health Protection of Consumers and Veterinary Medicine (BgVV), Thielallee 88-92, D-14195 Berlin, Germany
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Bernauer U, Garritsen H, Heinrich-Hirsch B, Gundert-Remy U. Immunochemical analysis of cytochrome P450 variability in human leukapheresed samples and its consequences for the risk assessment process. Regul Toxicol Pharmacol 2003; 37:318-27. [PMID: 12726760 DOI: 10.1016/s0273-2300(03)00012-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Xenobiotic metabolizing cytochrome P450 (P450) enzymes were investigated in leukapheresed samples from 50 human individuals. It was the aim of the study (a). to get insight into the extent of extrahepatic P450 variability, (b). to investigate whether and to which extent P450 expression and variability as it is seen in the liver corresponds to P450 expression at extrahepatic sites, and (c). to contribute to the replacement of traditionally used default factors (usually 10 for interindividual variability) by data-derived factors in the risk assessment process. P450 enzymes were determined by Western Blotting. Immunoquantification was performed for P450 1A, 1B1, 2C, 2D6, 2E1, and 3A which were-with the exception of the polymorphically expressed CYP2D6-detectable in all samples investigated. Amounts of P450 enzymes in leukapheresed samples were (except CYP1B1) lower compared to those reported for the liver. The P450 variabilities were expressed by the ratios between the 95th and the 5th percentiles. They displayed 7-(CYP1A), 4-(CYP1B1), 6-(CYP2C), 30-(CYP2D6), 3-(CYP2E1), and 4-(CYP3A) fold variability in specific protein content. The results show (a). qualitative and quantitative differences in the expression of P450 proteins in leukapheresed samples from 50 individuals compared to liver, (b). a different extent of variability depending on the P450 enzyme, and (c). in cases where polymorphically distributed P450 enzymes are involved, the traditionally used factor of 10 might be too low to account for interindividual variability in both toxicokinetics and toxicodynamics.
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Affiliation(s)
- Ulrike Bernauer
- Federal Institute for Health Protection of Consumers and Veterinary Medicine (BgVV), Thielallee 88-92, D-14195 Berlin, Germany.
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Abstract
The toxicokinetics and biotransformation of methyl-tert.butyl ether (MTBE), ethyl-tert.butyl ether (ETBE) and tert.amyl-methyl ether (TAME) in rats and humans are summarized. These ethers are used as gasoline additives in large amounts, and thus, a considerable potential for human exposure exists. After inhalation exposure MTBE, ETBE and TAME are rapidly taken up by both rats and humans; after termination of exposure, clearance by exhalation and biotransformation to urinary metabolites is rapid in rats. In humans, clearance by exhalation is slower in comparison to rats. Biotransformation of MTBE and ETBE is both qualitatively and quantitatively similar in humans and rats after inhalation exposure under identical conditions. The extent of biotransformation of TAME is also quantitatively similar in rats and humans; the metabolic pathways, however, are different. The results suggest that reactive and potentially toxic metabolites are not formed during biotransformation of these ethers and that toxic effects of these compounds initiated by covalent binding to cellular macromolecules are unlikely.
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Affiliation(s)
- W Dekant
- Department of Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg D, Germany.
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Runge DM, Stock TW, Lehmann T, Taege C, Bernauer U, Stolz DB, Hofmann S, Foth H. Expression of cytochrome P450 2E1 in normal human bronchial epithelial cells and activation by ethanol in culture. Arch Toxicol 2001; 75:335-45. [PMID: 11570691 DOI: 10.1007/s002040100248] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Serum-free primary cultures of human bronchial epithelial cells and freshly isolated samples of human bronchial epithelium were used to investigate basal expression of the cytochrome P450 enzyme CYP2E1 and its activation or induction by ethanol in bronchial epithelial cells. The cultures consisted of > or =95% cells of epithelial characteristics as determined by transmission electron microscopy and immunohistochemical staining. Monolayers were obtained from explants over a period of several months via transfer of tissue into new dishes ('generations'1-5). Using RT-PCR analysis, basal expression of mRNAs coding for CYP2B7, CYP2F1 and CYP2E1 were detected in cultures from several donors. The basal expression of CYP2E1 protein and mRNA showed differences between the donors. The mRNA was detected even in cultures from higher generations and increased in some cultures over time. The CYP2E1 protein content was low and in most cultures of generations 2-5 could not be detected by immunoblot analysis of native protein extracts. Nevertheless, in some cases immunoreactive CYP2E1 protein was present in monolayers obtained from the fourth and fifth transfer (18-week 'generation'). CYP2E1 activity was measured via 6-hydroxylation of chlorzoxazone either by a destructive assay using cell lysate or by a non-invasive assay using the medium of cell cultures. In short-term cultured isolated bronchial epithelium, ethanol treatment increased CYP2E1 activity by up to 5-fold within 4 days but with inter-individual differences. In cells up to 4 weeks in culture, CYP2E1 activity remained inducible by a single dose of ethanol. Differentiated primary human cells in culture may be useful tools as model systems for the evaluation of CYP2E1-driven processes in man.
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Affiliation(s)
- D M Runge
- Institute of Environmental Toxicology, Martin Luther University Halle-Wittenberg, Halle/Salle, Germany
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Dekant W, Bernauer U, Rosner E, Amberg A. Biotransformation of MTBE, ETBE, and TAME after inhalation or ingestion in rats and humans. Res Rep Health Eff Inst 2001:29-71; discussion 95-109. [PMID: 11504147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
The biotransformation of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) was studied in humans and in rats after inhalation of 4 and 40 ppm of MTBE, ETBE, and TAME, respectively, for 4 hours, and the biotransformation of MTBE and TAME was studied after ingestion exposure in humans to 5 and 15 mg in water. tert-Butyl alcohol (TBA), a TBA conjugate, 2-methyl-1,2-propanediol, and 2-hydroxyisobutyrate were found to be metabolites of MTBE and ETBE. tert-Amyl alcohol (TAA), free and glucuronidated 2-methyl-2,3-butanediol (a glucuronide of TAA), 2-hydroxy-2-methyl butyrate, and 3-hydroxy-3-methyl butyrate were found to be metabolites of TAME. After inhalation, MTBE, ETBE, and TAME were rapidly taken up by both rats and humans; after termination of exposure, clearance from blood of the ethers by exhalation and biotransformation to urinary metabolites occurred with half-times of less than 7 hours in rats and humans. Biotransformation of MTBE and ETBE was similar in humans and rats after inhalation exposure. 2-Hydroxyisobutyrate was recovered as a major product in urine. All metabolites of MTBE and ETBE excreted with urine were eliminated with half-times of less than 20 hours. Biotransformation of TAME was qualitatively similar in rats and humans, but the metabolic pathways were different. In humans, 2-methyl-2,3-butanediol, 2-hydroxy-2-methyl butyrate, and 3-hydroxy-3methyl butyrate were recovered as major urinary products. In rats, however, 2-methyl-2,3-butanediol and its glucuronide were major TAME metabolites recovered in urine. After ingestion of MTBE and TAME, both compounds were rapidly absorbed from the gastrointestinal tract. Hepatic first-pass metabolism of these ethers was not observed, and a significant part of the administered dose was transferred into blood and cleared by exhalation. Metabolic pathways for MTBE and TAME and kinetics of excretion were identical after ingestion and inhalation exposures. Results of studies presented here suggest (1) that excretion of MTBE, ETBE, and TAME in rats and humans is rapid, (2) that biotransformation and excretion of MTBE and ETBE are identical in rats, and (3) that biotransformation and excretion of TAME is quantitatively different in rats and humans.
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Affiliation(s)
- W Dekant
- Department of Toxicology, University of Würzburg, Germany
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Bernauer U, Vieth B, Ellrich R, Heinrich-Hirsch B, Jänig GR, Gundert-Remy U. CYP2E1 expression in bone marrow and its intra- and interspecies variability: approaches for a more reliable extrapolation from one species to another in the risk assessment of chemicals. Arch Toxicol 2000; 73:618-24. [PMID: 10741472 DOI: 10.1007/s002040050016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
When characterizing the health risks for man by exposure to chemicals, species-specific differences have to be taken into consideration, otherwise extrapolation from animal data to the human situation would be inadequate. The site-specific toxicity of chemicals may be explained by the following alternatives: (1) reactive metabolites are generated in the liver and subsequently transported to the target tissue(s); (2) metabolism of the parent compound occurs in the target tissue, a pathway by which the enzymes necessary for activation must be expressed in the target tissue. Cytochrome P450 2E1 (CYP2E1) is an important phase-I enzyme activating several chemicals. In the study described in this paper, myeloid intra- and interspecies variability in the expression of CYP2E1 has been investigated in rats, rabbits and man, because the bone marrow represents an important target organ for toxic effects of several chemicals, e.g. benzene. CYP2E1 at the protein level was detected by Western blotting and enzyme activities were determined by CYP2E1-dependent hydroxylation of chlorzoxazone (CLX). In the bone marrow of Wistar rats, the CLX hydroxylase activities were within the same order of magnitude (range: 0.1-0.4 pmol/mg protein per min) as previously described for mice (range 0.2-0.8 pmol/mg protein per min), whereas the CYP2E1 activities in two strains of rabbits were significantly higher (range: 1.7-4.7 pmol/mg protein per min) than in the rodents (P < 0.05). In human CD34+ bone marrow stem cells, CYP2E1 could also be detected on the protein level by Western blotting. The data demonstrate a presence of CYP2E1 in the bone marrow of all species investigated, thus supporting the hypothesis of CYP2E1-dependent local metabolism of several chemicals as a factor possibly contributing to their myelotoxicity and haematotoxicity. The data show that intraspecies/intrastrain variability of CYP2E1 activity in rodents is small. However, CYP2E1 activity between rodents and a non-rodent species was quite different indicating considerable interspecies variability.
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Affiliation(s)
- U Bernauer
- Federal Institute for Health Protection of Consumers and Veterinary Medicine, Berlin (BgVV), Germany
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Abstract
tert-Amyl methyl ether (TAME) is intended for use as a gasoline additive to increase oxygen content. Increased oxygen content in gasoline reduces tailpipe emissions of hydrocarbons and carbon monoxide from cars. Due to possible widespread use of TAME, the toxicity of TAME is under investigation. We studied the biotransformation of TAME in rats and one human volunteer after inhalation of (12)C- or (13)C-labeled TAME. In addition, the biotransformation of [(13)C]-tert-amyl alcohol was studied in rats after gavage. Urinary metabolites were identified by GC/MS and (13)C NMR. Rats (two males and two females) were individually exposed to 2000 ppm [(12)C]- or [(13)C]TAME for 6 h, and urine was collected for 48 h. Free and glucuronidated 2-methyl-2,3-butanediol and a glucuronide of tert-amyl alcohol were identified by (13)C NMR, GC/MS, and LC/MS/MS as major urinary metabolites on the basis of the relative intensities of the (13)C NMR signals. The presence of several minor metabolites was also indicated by (13)C NMR; they were identified as tert-amyl alcohol, 2-hydroxy-2-methylbutyric acid, and 3-hydroxy-3-methylbutyric acid. One human volunteer was exposed to an initial concentration of 27 000 ppm [(13)C]TAME by inhalation for 4 min from a 2 L gas sampling bag, and metabolites of TAME excreted in urine were analyzed by (13)C NMR. All TAME metabolites identified in rats were also present in the human urine samples. To study tert-amyl alcohol biotransformation, male rats (n = 3) were treated with 250 mg/kg [(13)C]-tert-amyl alcohol dissolved in corn oil by gavage, and urine was collected for 48 h. (13)C NMR of the urine samples showed the presence of metabolites identical to those in the urine of [(13)C]TAME-treated rats. Our results suggest that TAME is extensively metabolized by rats and humans to tert-amyl alcohol which may be further oxidized to diols and carboxylic acids. These reactions are likely mediated by cytochrome P450-dependent oxidations.
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Affiliation(s)
- A Amberg
- Institut für Toxikologie, Universität Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
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Bernauer U, Vieth B, Ellrich R, Heinrich-Hirsch B, Jänig GR, Gundert-Remy U. CYP2E1-dependent benzene toxicity: the role of extrahepatic benzene metabolism. Arch Toxicol 1999; 73:189-96. [PMID: 10463382 DOI: 10.1007/s002040050605] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Benzene, a ubiquitous environmental pollutant, is haematotoxic and myelotoxic. As has been shown earlier, cytochrome P450 2E1 (CYP2E1)-dependent metabolism is a prerequisite for the cytotoxic and genotoxic effects of benzene, but which of the benzene metabolites produces toxicity is still unknown. The observed differences between the toxicity of benzene and that of phenol, a major metabolite of benzene, could be explained by alternative hypotheses. That is, whether (1) toxic benzene effects are caused by metabolites not derived from phenol (e.g. benzene epoxide, muconaldehyde). which are formed in the liver and are able to reach the target organ(s); or (2) benzene penetrates into the bone marrow, where local metabolism takes place, whereas phenol does not reach the target tissue because of its polarity. To further investigate hypothesis 2, we used various strains of mice (AKR, B6C3F1, CBA/Ca, CD-1 and C57B1/6), for which different toxic responses have been reported in the haematopoietic system after chronic benzene exposure. In these strains, CYP2E1 expression in bone marrow was investigated and compared with CYP2E1 expression in liver by means of two independent methods. Quantification of CYP2E1-dependent hydroxylation of chlorzoxazone (CLX) by high-performance liquid chromatography (HPLC; functional analysis) was used to characterize specific enzymatic activities. Protein identification was performed by Western blotting using CYP2E1-specific antibodies. In liver microsomes of all strains investigated, considerable amounts of CYP2E1-specific protein and correspondingly high CYP2E1 hydroxylase activities could be detected. No significant differences in CYP2E1-dependent enzyme activities were found between the five strains (range of medians, 4.6 12.0 nmol 6-OH-CLX/[mg protein x min]) in hepatic tissue. In the bone marrow, CYP2E1 could also be detected in all strains investigated. However, chlorzoxazone hydroxylase activities were considerably lower (range of medians, 0.2-0.8x10(-3) nmol 6-OH-CLX/[mg protein x min]) compared with those obtained from liver microsomes. No significant (P>0.05) interstrain differences in CYP2E1 expression in liver and/or bone marrow could be observed in the mouse strains investigated. The data obtained thus far from our investigations suggest that strain-specific differences in the tumour response of the haematopoietic system of mice chronically exposed to benzene cannot be explained by differences in either hepatic or in myeloid CYP2E1-dependent metabolism of benzene.
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Affiliation(s)
- U Bernauer
- Federal Institute for Health Protection of Consumers and Veterinary Medicine (BgVV), Berlin, Germany.
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Bernauer U, Amberg A, Scheutzow D, Dekant W. Biotransformation of 12C- and 2-13C-labeled methyl tert-butyl ether, ethyl tert-butyl ether, and tert-butyl alcohol in rats: identification of metabolites in urine by 13C nuclear magnetic resonance and gas chromatography/mass spectrometry. Chem Res Toxicol 1998; 11:651-8. [PMID: 9625733 DOI: 10.1021/tx970215v] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The biotransformation of the fuel oxygenates methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) was studied in rats after inhalation exposure; the biotransformation of the initial metabolite of these ethers, tert-butyl alcohol, was studied after oral gavage. To study ether metabolism, rats were exposed for 6 h to initial concentrations of 2000 ppm of MTBE or ETBE, respectively [2-13C]MTBE and [2-13C]ETBE. Urine was collected for 48 h after the end of the exposure, and urinary metabolites were identified by 13C NMR (13C-labeled ethers) and gas chromatography/mass spectrometry (GC/MS) (12C- and 13C-labeled ethers). To study tert-butyl alcohol metabolism, rats were dosed either with tert-butyl alcohol at natural carbon isotope ratio or with 13C-enriched tert-butyl alcohol (250 mg/kg of body weight), urine was collected, and metabolites were identified by NMR and GC/MS. tert-Butyl alcohol was identified as a minor product of the biotransformation of MTBE and ETBE. In addition, small amounts of a tert-butyl alcohol conjugate, likely a glucuronide, were present in the urine of the treated animals. Moreover, the mass spectra obtained indicate the presence of small amounts of [13C]acetone in the urine of [13C]MTBE and [13C]ETBE-treated rats. 2-Methyl-1,2-propanediol, 2-hydroxyisobutyrate, and another unidentified conjugate of tert-butyl alcohol, most probably a sulfate, were major urinary metabolites of MTBE and ETBE as judged by the intensities of the NMR signals. In [13C]-tert-butyl alcohol-dosed rats, [13C]acetone, tert-butyl alcohol, and its glucuronide represented minor metabolites; as with the ethers, 2-methyl-1,2-propanediol, 2-hydroxyisobutyrate, and the presumed tert-butyl alcohol sulfate were the major metabolites present. In one human individual given 5 mg/kg [13C]-tert-butyl alcohol orally, 2-methyl-1,2-propanediol and 2-hydroxyisobutyrate were major metabolites in urine detected by 13C NMR analysis. Unconjugated tert-butyl alcohol and tert-butyl alcohol glucuronide were present as minor metabolites, and traces of the presumed tert-butyl alcohol sulfate were also present. Our results suggest that tert-butyl alcohol formed from MTBE and ETBE is intensively metabolized by further oxidation reactions. Studies to elucidate mechanisms of toxicity for these ethers to the kidney need to consider potential toxicities induced by these metabolites.
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Affiliation(s)
- U Bernauer
- Institut für Toxikologie, Universität Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
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Abstract
The formation of cysteine S-conjugates is thought to play an important role in the nephrotoxicity of haloalkenes such as trichloroethene, tetrachloroethene and hexachlorobutadiene. Glutathione S-conjugates formed from these haloalkenes in the liver are processed to the corresponding cysteine S-conjugates, which may be N-acetylated to mercapturic acids and may be accumulated in the kidney. Haloalkene-derived cysteine S-conjugates are also substrates for cysteine conjugate beta-lyases and reactive intermediates are formed in this reaction. The equilibrium between cysteine S-conjugate and mercapturic acid thus influences the extent of beta-lyase dependent bioactivation and subsequently the nephrotoxicity of S-conjugates. In this study, we compared the rates of N-acetylation in vitro and the biotransformation, excretion and nephrotoxicity of S-(1,2-dichlorovinyl)-L-cysteine (1,2-DCVC), S-(2,2-dichlorovinyl)-L-cysteine (2,2-DCVC), S-(1,2,2-trichlorovinyl)-L-cysteine (TCVC) and S-(1,2,3,4,4-pentachlorobutadienyl)-L-cysteine (PCBC) in rats after i.v. injection (40 micromoles/kg). Marked differences in the extent of enzymatic N-acetylation were observed; N-acetylation was most efficient with 2,2-DCVC and least efficient with 1,2-DCVC. In urine, within 48 h, most of the given 2,2-DCVC (77% of the recovered dose) and 1,2-DCVC (92%) were recovered as the corresponding mercapturic acids. In contrast, a higher percentage of cysteine S-conjugate and less of the mercapturic acid were recovered in urine after administration of PCBC and TCVC (50 and 23% of dose as mercapturic acid), respectively. Histopathological examination of the kidneys and urine clinical chemistry showed marked differences in the extent of renal damage. Necroses of the proximal tubules were found after TCVC, PCBC and 1,2-DCVC administration in male, but not in female rats. These differences in nephrotoxicity do not correlate with the balance of acetylation/deacetylation. The higher toxicity observed in male rats may indicate the involvement of other parameters such as uptake mechanisms.
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Affiliation(s)
- G Birner
- Department of Toxicology, University of Würzburg, Germany
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Bernauer U, Birner G, Dekant W, Henschler D. Biotransformation of trichloroethene: dose-dependent excretion of 2,2,2-trichloro-metabolites and mercapturic acids in rats and humans after inhalation. Arch Toxicol 1996; 70:338-46. [PMID: 8975632 DOI: 10.1007/s002040050283] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Chronic bioassays with trichloroethene (TRI) demonstrated carcinogenicity in mice (hepatocellular carcinomas) and rats (renal tubular cell adenomas and carcinomas). The chronic toxicity and carcinogenicity is due to bioactivation reactions. TRI is metabolized by cytochrome P450 and by conjugation with glutathione. Glutathione conjugation results in S-(dichlorovinyl) glutathione (DCVG) and is presumed to be the initial biotransformation step resulting in the formation of nephrotoxic metabolites. Enzymes of the mercapturic acid pathway cleave DCVG to the corresponding cysteine S-conjugate, which is, after translocation to the kidney, cleaved by renal cysteine S-conjugate beta -lyase to the electrophile chlorothioketene. After N-acetylation, cysteine S-conjugates are also excreted as mercapturic acids in urine. The object of this study was the dose-dependent quantification of the two isomers of N-acetyl-S-(dichlorovinyl)-L-cysteine, trichloroethanol and trichloroacetic acid, as markers for the glutathione- and cytochrome P450-mediated metabolism, respectively, in the urine of humans and rats after exposure to TRI. Three male volunteers and four rats were exposed to 40, 80 and 160 ppm TRI for 6 h. A dose-dependent increase in the excretion of trichloroacetic acid, trichloroethanol and N-acetyl-S-(dichlorovinyl)-L-cysteine after exposure to TRI was found both in humans and rats. Amounts of 3100 mumol trichloroacetic acid + trichloroethanol and 0.45 mumol mercapturic acids were excreted in urine of humans over 48 h after exposure to 160 ppm TRI. The ratio of trichloroacetic acid + trichloroethanol/mercapturic acid excretion was comparable in rats and humans. A slow rate of elimination with urine of N-acetyl-S-(dichlorovinyl)-L-cysteine was observed both in humans and in rats. However, the ratio of the two isomers of N-acetyl-S-(dichlorovinyl)-L-cysteine was different in man and rat. The results confirm the finding of the urinary excretion of mercapturic acids in humans after TRI exposure and suggest the formation of reactive intermediates in the metabolism of TRI after bioactivation by glutathione also in humans.
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Affiliation(s)
- U Bernauer
- Institut für Toxikologie, Universität Würzburg, Germany
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Gillmann H, Bernauer U. [Comparative studies between electrocardiographic infarct localization and topographic-anatomical localization]. Z Kreislaufforsch 1972; 61:781-8. [PMID: 4637849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Bernauer U. [Errors in blood pressure determination]. Med Klin 1969; 64:1379-82. [PMID: 4895523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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