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Role of the human N-acetyltransferase 2 genetic polymorphism in metabolism and genotoxicity of 4, 4'-methylenedianiline. Arch Toxicol 2019; 93:2237-2246. [PMID: 31292670 DOI: 10.1007/s00204-019-02516-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/04/2019] [Indexed: 01/06/2023]
Abstract
4, 4'-Methylenedianiline (MDA) is used extensively as a curing agent in the production of elastomers and is classified as reasonably anticipated to be a human carcinogen based on sufficient evidence in animal experiments. Human N-acetyltransferase 1 (NAT1) and 2 (NAT2) catalyze the N-acetylation of aromatic amines and NAT2 is subjected to a common genetic polymorphism in human populations separating individuals into rapid, intermediate, and slow acetylator phenotypes. Although MDA is known to undergo N-acetylation to mono- and di-acetyl metabolites, very little is known regarding whether this metabolism is subject to the NAT2 genetic polymorphism. We investigated the N-acetylation of MDA by recombinant human NAT1, NAT2, genetic variants of NAT2, and cryoplateable human hepatocytes obtained from rapid, intermediate and slow acetylators. MDA N-acetylation was catalyzed by both recombinant human NAT1 and NAT2 exhibiting a fivefold higher affinity for human NAT2. N-acetylation of MDA was acetylator genotype dependent as evidenced via its N-acetylation by recombinant human NAT2 genetic variants or by cryoplateable human hepatocytes. MDA N-acetylation to the mono-acetyl or di-acetyl-MDA was highest in rapid, lower in intermediate, and lowest in slow acetylator human hepatocytes. MDA-induced DNA damage in the human hepatocytes was dose-dependent and also acetylator genotype dependent with highest levels of DNA damage in rapid, lower in intermediate, and lowest in slow acetylator human hepatocytes under the same MDA exposure level. In summary, the N-acetylation of MDA by recombinant human NAT2 and cryopreserved human hepatocytes support an important role for the NAT2 genetic polymorphism in modifying MDA metabolism and genotoxicity and potentially carcinogenic risk.
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Lewandowski TA, Hayes AW, Beck BD. Risk evaluation of occupational exposure to methylene dianiline and toluene diamine in polyurethane foam. Hum Exp Toxicol 2016; 24:655-62. [PMID: 16408619 DOI: 10.1191/0960327105ht587oa] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Methylene diphenylisocyanate (MDI) and toluene diisocyanate (TDI) are widely used in industry to produce polyurethane foam products. Small amounts of methylenedianiline (MDA) and toluene diamine (TDA) are released during MDI and TDI polymerization and may be present in newly finished polyurethane foam parts. MDA and TDA concentrations in foam decline exponentially within several hours of demolding. MDA and the 2,4-isomer of TDA are known animal carcinogens and, in addition, have significant non-carcinogenic health effects. Our goal was to determine whether worker exposure to MDA or TDA in freshly produced polyurethane foams was associated with unacceptable health risks. Sampling and analysis of the fresh foam indicated that MDA and TDA concentrations varied considerably among products, but concentrations in all materials evaluated declined rapidly over time. We found that, under a worst-case exposure scenario, cancer risks from TDA exposure were approximately 5-10 6, whereas cancer risks from MDA exposure resulted in a tumorigenic margin of exposure (MOE) of 85 000. Non-cancer chronic hazard indices were well below 1.0. Therefore, the potential cancer and non-cancer health risks from MDA or TDA exposure to newly manufactured foam parts appear to fall well within acceptable health risk criteria.
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Affiliation(s)
- T A Lewandowski
- Gradient Corporation, 600 Stewart St., Suite 803, Seattle, WA 98101, USA.
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Wahlang B, Beier JI, Clair HB, Bellis-Jones HJ, Falkner KC, McClain CJ, Cave MC. Toxicant-associated steatohepatitis. Toxicol Pathol 2013; 41:343-60. [PMID: 23262638 PMCID: PMC5114851 DOI: 10.1177/0192623312468517] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hepatotoxicity is the most common organ injury due to occupational and environmental exposures to industrial chemicals. A wide range of liver pathologies ranging from necrosis to cancer have been observed following chemical exposures both in humans and in animal models. Toxicant-associated fatty liver disease (TAFLD) is a recently named form of liver injury pathologically similar to alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD). Toxicant-associated steatohepatitis (TASH) is a more severe form of TAFLD characterized by hepatic steatosis, inflammatory infiltrate, and in some cases, fibrosis. While subjects with TASH have exposures to industrial chemicals, such as vinyl chloride, they do not have traditional risk factors for fatty liver such as significant alcohol consumption or obesity. Conventional biomarkers of hepatotoxicity including serum alanine aminotransferase activity may be normal in TASH, making screening problematic. This article examines selected chemical exposures associated with TAFLD in human subjects or animal models and concisely reviews the closely related NAFLD and ALD.
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Affiliation(s)
- Banrida Wahlang
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Juliane I. Beier
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Heather B. Clair
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Heather J. Bellis-Jones
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - K. Cameron Falkner
- Department of Medicine, Division of Gastroenterology, Hepatology, and Nutrition, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Craig J. McClain
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Medicine, Division of Gastroenterology, Hepatology, and Nutrition, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Robley Rex Louisville VAMC, Louisville, Kentucky, USA
| | - Matt C. Cave
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Medicine, Division of Gastroenterology, Hepatology, and Nutrition, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Robley Rex Louisville VAMC, Louisville, Kentucky, USA
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Österreicher CH, Trauner M. Xenobiotic-induced liver injury and fibrosis. Expert Opin Drug Metab Toxicol 2012; 8:571-80. [PMID: 22452290 DOI: 10.1517/17425255.2012.674511] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Many different drugs and xenobiotics (chemical compounds foreign to an organism) can injure the bile duct epithelium and cause inflammatory bile duct diseases (cholangiopathies) ranging from transient cholestasis to vanishing bile duct syndrome, sclerosing cholangitis with development of biliary fibrosis and cirrhosis. Animal models of xenobiotic-induced liver injury have provided major mechanistic insights into the molecular mechanisms of xenobiotic-induced cholangiopathies and biliary fibrosis including primary biliary cirrhosis and primary sclerosing cholangitis. AREAS COVERED In this review, the authors discuss the basic principles of xenobiotic-induced liver and bile duct injury and biliary fibrosis with emphasis on animal models. A PubMed search was performed using the search terms "xenobiotic," "liver injury," "cholestasis," and "biliary fibrosis." Reference lists of retrieved articles were also searched for relevant literature. EXPERT OPINION Xenobiotic-induced cholangiopathies are underestimated and frequently overlooked medical conditions due to their often transient nature. However, biliary disease may progress to vanishing bile duct syndrome, biliary fibrosis, and cirrhosis. Moreover, xenobiotics may prime the liver for subsequent liver disease by other agents and may also contribute to the development of hepatobiliary cancer though interaction with resident stem cells.
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Affiliation(s)
- Christoph H Österreicher
- Medical University of Vienna, Institute of Pharmacology, Center for Physiology and Pharmacology, Vienna, Austria
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Dermal Uptake and Excretion of 4,4′-Methylenedianiline during Rotor Blade Production in Helicopter Industry—An Intervention Study. ANNALS OF OCCUPATIONAL HYGIENE 2011; 55:886-92. [DOI: 10.1093/annhyg/mer051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Giouleme O, Karabatsou S, Hytiroglou P, Xanthis A, Tsiaousi E, Katsaros M, Koliouskas D. 4,4'-Methylenedianiline-induced hepatitis in an industrial worker: case report and review of the literature. Hum Exp Toxicol 2010; 30:762-7. [PMID: 20621954 DOI: 10.1177/0960327110376549] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
4,4'-Methylenedianiline (MDA) is a chemical used in manufacturing and insulation processes and is a well-known hepatotoxin. We report the case of a 42-year-old construction-site worker who was accidentally exposed to large amounts of MDA and developed acute liver damage. The clinical course is described, with particular emphasis on the timely identification of the underlying cause and prompt management that led to an uneventful recovery. We review the relevant literature and discuss the safety measures necessary to minimize similar occupational hazards in industrial workers.
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Affiliation(s)
- Olga Giouleme
- First Propedeutic Department of Internal Medicine, Medical School, Aristotle University of Thessaloniki, AHEPA Hospital, Thessaloniki, Greece.
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Oh JH, Yoon HJ, Lim JS, Park HJ, Cho JW, Kwon MS, Yoon S. Analysis of Gene Expression in 4,4'-Methylenedianiline-induced Acute Hepatotoxicity. Toxicol Res 2009; 25:85-92. [PMID: 32038824 PMCID: PMC7006339 DOI: 10.5487/tr.2009.25.2.085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 05/13/2009] [Accepted: 05/13/2009] [Indexed: 01/06/2023] Open
Abstract
4,4′-Methylenedianiline (MDA) is an aromatic amine that is widely used in the industrial synthetic process. Genotoxic MDA forms DNA adducts in the liver and is known to induce liver damage in human and rats. To elucidate the molecular mechanisms associated with MDA-induced hepatotoxicity, we have identified genes differentially expressed by microarray approach. BALB/c male mice were treated once daily with MDA (20 mg/kg) up to 7 days via intraperitoneal injection (i.p.) and hepatic damages were revealed by histopathological observation and elevation of serum marker enzymes such as AST, ALT, ALP, cholesterol, DBIL, and TBIL. Microarray analysis showed that 952 genes were differentially expressed in the liver of MDA-treated mice and their biological functions and canonical pathways were further analyzed using Ingenuity Pathways Analysis (IPA). Toxicological functional analysis showed that genes related to hepatotoxicity such hyperplasia/hyperproliferation (Timpl), necrosis/cell death (Cd14, Mt1f, Timpl, and Pmaipl), hemorrhaging (Mt1f), cholestasis (Akr1c3, Hpx, and Slc10a2), and inflammation (Cd14 and Hpx) were differentially expressed in MDA-treated group. This gene expression profiling should be useful for elucidating the genetic events associated with aromatic amine-induced hepatotoxicity and for discovering the potential biomarkers for hepatotoxicity.
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Affiliation(s)
- Jung-Hwa Oh
- 14Toxicogenomics Team, Korea Institute of Toxicology, 19 Shinsung-ro, Yuseoung, Daejeon, 305-343 Korea
| | - Hea-Jin Yoon
- 14Toxicogenomics Team, Korea Institute of Toxicology, 19 Shinsung-ro, Yuseoung, Daejeon, 305-343 Korea
| | - Jung-Sun Lim
- 14Toxicogenomics Team, Korea Institute of Toxicology, 19 Shinsung-ro, Yuseoung, Daejeon, 305-343 Korea
| | - Han-Jin Park
- 14Toxicogenomics Team, Korea Institute of Toxicology, 19 Shinsung-ro, Yuseoung, Daejeon, 305-343 Korea
| | - Jae-Woo Cho
- 24Clinical Pathology Team, Korea Institute of Toxicology, 19 Shinsung-ro, Yuseoung, Daejeon, 305-343 Korea
| | - Myung-Sang Kwon
- 34Korea Institute of Toxicology, 19 Shinsung-ro, Yuseoung, Daejeon, 305-343 Korea.,44School of Veterinary Medicine, Kangwon National University, Chuncheon, 200-701 Korea
| | - Seokjoo Yoon
- 14Toxicogenomics Team, Korea Institute of Toxicology, 19 Shinsung-ro, Yuseoung, Daejeon, 305-343 Korea
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