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Bates CA, Haber LT, Moore MM, Schoeny R, Maier A. Development of a framework for risk assessment of dietary carcinogens. Food Chem Toxicol 2023; 180:114022. [PMID: 37716495 DOI: 10.1016/j.fct.2023.114022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 08/09/2023] [Accepted: 09/01/2023] [Indexed: 09/18/2023]
Abstract
Although there are a number of guidance documents and frameworks for evaluation of carcinogenicity, none of the current methods fully reflects the state of the science. Common limitations include the absence of dose-response assessment and not considering the impact of differing exposure patterns (e.g., intermittent, high peaks vs. lower, continuous exposures). To address these issues, we have developed a framework for risk assessment of dietary carcinogens. This framework includes an enhanced approach for weight of evidence (WOE) evaluation for genetic toxicology data, with a focus on evaluating studies based on the most recent testing guidance to determine whether a chemical is a mutagen. Included alongside our framework is a discussion of resources for evaluating tissue dose and the temporal pattern of internal dose, taking into account the chemical's toxicokinetics. The framework then integrates the mode of action (MOA) and associated dose metric category with the exposure data to identify the appropriate approach(es) to low-dose extrapolation and level of concern associated with the exposure scenario. This framework provides risk managers with additional flexibility in risk management and risk communication options, beyond the binary choice of linear low-dose extrapolation vs. application of uncertainty factors.
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Affiliation(s)
| | - Lynne T Haber
- Risk Science Center, University of Cincinnati College of Medicine, USA
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Kuo B, Beal MA, Wills JW, White PA, Marchetti F, Nong A, Barton-Maclaren TS, Houck K, Yauk CL. Comprehensive interpretation of in vitro micronucleus test results for 292 chemicals: from hazard identification to risk assessment application. Arch Toxicol 2022; 96:2067-2085. [PMID: 35445829 PMCID: PMC9151546 DOI: 10.1007/s00204-022-03286-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/23/2022] [Indexed: 11/08/2022]
Abstract
Risk assessments are increasingly reliant on information from in vitro assays. The in vitro micronucleus test (MNvit) is a genotoxicity test that detects chromosomal abnormalities, including chromosome breakage (clastogenicity) and/or whole chromosome loss (aneugenicity). In this study, MNvit datasets for 292 chemicals, generated by the US EPA's ToxCast program, were evaluated using a decision tree-based pipeline for hazard identification. Chemicals were tested with 19 concentrations (n = 1) up to 200 µM, in the presence and absence of Aroclor 1254-induced rat liver S9. To identify clastogenic chemicals, %MN values at each concentration were compared to a distribution of batch-specific solvent controls; this was followed by cytotoxicity assessment and benchmark concentration (BMC) analyses. The approach classified 157 substances as positives, 25 as negatives, and 110 as inconclusive. Using the approach described in Bryce et al. (Environ Mol Mutagen 52:280-286, 2011), we identified 15 (5%) aneugens. IVIVE (in vitro to in vivo extrapolation) was employed to convert BMCs into administered equivalent doses (AEDs). Where possible, AEDs were compared to points of departure (PODs) for traditional genotoxicity endpoints; AEDs were generally lower than PODs based on in vivo endpoints. To facilitate interpretation of in vitro MN assay concentration-response data for risk assessment, exposure estimates were utilized to calculate bioactivity exposure ratio (BER) values. BERs for 50 clastogens and two aneugens had AEDs that approached exposure estimates (i.e., BER < 100); these chemicals might be considered priorities for additional testing. This work provides a framework for the use of high-throughput in vitro genotoxicity testing for priority setting and chemical risk assessment.
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Affiliation(s)
- Byron Kuo
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Marc A Beal
- Bureau of Chemical Safety, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - John W Wills
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
- Biominerals Research, Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, UK
| | - Paul A White
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Francesco Marchetti
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Andy Nong
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Tara S Barton-Maclaren
- Existing Substances Risk Assessment Bureau, Safe Environments Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada
| | - Keith Houck
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environment and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada.
- Department of Biology, University of Ottawa, 30 Marie Curie Private, Room 269, Ottawa, ON, K1N 6N5, Canada.
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Röhl C, Batke M, Damm G, Freyberger A, Gebel T, Gundert-Remy U, Hengstler JG, Mangerich A, Matthiessen A, Partosch F, Schupp T, Wollin KM, Foth H. New aspects in deriving health-based guidance values for bromate in swimming pool water. Arch Toxicol 2022; 96:1623-1659. [PMID: 35386057 PMCID: PMC9095538 DOI: 10.1007/s00204-022-03255-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 02/17/2022] [Indexed: 11/27/2022]
Abstract
Bromate, classified as a EU CLP 1B carcinogen, is a typical by-product of the disinfection of drinking and swimming pool water. The aim of this study was (a) to provide data on the occurrence of bromate in pool water, (b) to re-evaluate the carcinogenic MOA of bromate in the light of existing data, (c) to assess the possible exposure to bromate via swimming pool water and (d) to inform the derivation of cancer risk-related bromate concentrations in swimming pool water. Measurements from monitoring analysis of 229 samples showed bromate concentrations in seawater pools up to 34 mg/L. A comprehensive non-systematic literature search was done and the quality of the studies on genotoxicity and carcinogenicity was assessed by Klimisch criteria (Klimisch et al., Regul Toxicol Pharmacol 25:1-5, 1997) and SciRAP tool (Beronius et al., J Appl Toxicol, 38:1460-1470, 2018) respectively. Benchmark dose (BMD) modeling was performed using the modeling average mode in BMDS 3.1 and PROAST 66.40, 67 and 69 (human cancer BMDL10; EFSA 2017). For exposure assessment, data from a wide range of sources were evaluated for their reliability. Different target groups (infants/toddlers, children and adults) and exposure scenarios (recreational, sport-active swimmers, top athletes) were considered for oral, inhalation and dermal exposure. Exposure was calculated according to the frequency of swimming events and duration in water. For illustration, cancer risk-related bromate concentrations in pool water were calculated for different target groups, taking into account their exposure using the hBMDL10 and a cancer risk of 1 in 100,000. Convincing evidence was obtained from a multitude of studies that bromate induces oxidative DNA damage and acts as a clastogen in vitro and in vivo. Since statistical modeling of the available genotoxicity data is compatible with both linear as well as non-linear dose-response relationships, bromate should be conservatively considered to be a non-threshold carcinogen. BMD modeling with model averaging for renal cancer studies (Kurokawa et al., J Natl. Cancer Inst, 1983 and 1986a; DeAngelo et al., Toxicol Pathol 26:587-594, 1998) resulted in a median hBMDL10 of 0.65 mg bromate/kg body weight (bw) per day. Evaluation of different age and activity groups revealed that top athletes had the highest exposure, followed by sport-active children, sport-active adults, infants and toddlers, children and adults. The predominant route of exposure was oral (73-98%) by swallowing water, followed by the dermal route (2-27%), while the inhalation route was insignificant (< 0.5%). Accepting the same risk level for all population groups resulted in different guidance values due to the large variation in exposure. For example, for an additional risk of 1 in 100,000, the bromate concentrations would range between 0.011 for top athletes, 0.015 for sport-active children and 2.1 mg/L for adults. In conclusion, the present study shows that health risks due to bromate exposure by swimming pool water cannot be excluded and that large differences in risk exist depending on the individual swimming habits and water concentrations.
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Affiliation(s)
- C Röhl
- Institute of Toxicology and Pharmacology for Natural Scientists, Christiana Albertina University Kiel, Kiel, Germany.
- Department of Environmental Health Protection, State Agency for social Services (LAsD) Schleswig-Holstein, Neumünster, Germany.
| | - M Batke
- University Emden/Leer, Emden, Germany
| | - G Damm
- Department of Hepatobiliary Surgery and Visceral Transplantation, University Hospital, Leipzig University, Leipzig, Germany
| | - A Freyberger
- Research and Development, Pharmaceuticals, RED-PCD-TOX-P&PC Clinical Pathology, Bayer AG, Wuppertal, Germany
| | - T Gebel
- Federal Institute for Occupational Safety and Health (BAuA), Dortmund, Germany
| | - U Gundert-Remy
- Institute for Clinical Pharmacology and Toxicology, Universitätsmedizin Berlin, Charité Berlin, Germany
| | - J G Hengstler
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), TU Dortmund University, Dortmund, Germany
| | - A Mangerich
- Molecular Toxicology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - A Matthiessen
- Central Unit for Environmental Hygiene, University Hospital Schleswig-Holstein (UKSH), Kiel, Germany
| | - F Partosch
- Department of Toxicology, Fraunhofer-Institute for Toxicology and Experimental Medicine (ITEM), Hannover, Germany
| | - T Schupp
- Department of Chemical Engineering, University of Applied Science Muenster, Steinfurt, Germany
| | - K M Wollin
- Formerly Public Health Agency of Lower Saxony, Hannover, Germany
| | - H Foth
- Institute of Environmental Toxicology, University of Halle, Halle/Saale, Germany
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Blackshear PE, Pandiri AR, Nagai H, Bhusari S, Hong HH, Ton TVT, Clayton NP, Wyde M, Shockley KR, Peddada SD, Gerrish KE, Sills RC, Hoenerhoff MJ. Gene expression of mesothelioma in vinylidene chloride-exposed F344/N rats reveal immune dysfunction, tissue damage, and inflammation pathways. Toxicol Pathol 2015; 43:171-85. [PMID: 24958746 PMCID: PMC4275413 DOI: 10.1177/0192623314537885] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A majority (∼80%) of human malignant mesotheliomas are asbestos-related. However, non-asbestos risk factors (radiation, chemicals, and genetic factors) account for up to 30% of cases. A recent 2-year National Toxicology Program carcinogenicity bioassay showed that male F344/N rats exposed to the industrial toxicant vinylidene chloride (VDC) resulted in a marked increase in malignant mesothelioma. Global gene expression profiles of these tumors were compared to spontaneous mesotheliomas and the F344/N rat mesothelial cell line (Fred-PE) in order to characterize the molecular features and chemical-specific profiles of mesothelioma in VDC-exposed rats. As expected, mesotheliomas from control and VDC-exposed rats shared pathways associated with tumorigenesis, including cellular and tissue development, organismal injury, embryonic development, inflammatory response, cell cycle regulation, and cellular growth and proliferation, while mesotheliomas from VDC-exposed rats alone showed overrepresentation of pathways associated with pro-inflammatory pathways and immune dysfunction such as the nuclear factor kappa-light-chain-enhancer of activated B cells signaling pathway, interleukin (IL)-8 and IL-12 signaling, interleukin responses, Fc receptor signaling, and natural killer and dendritic cells signaling, as well as overrepresentation of DNA damage and repair. These data suggest that a chronic, pro-inflammatory environment associated with VDC exposure may exacerbate disturbances in oncogene, growth factor, and cell cycle regulation, resulting in an increased incidence of mesothelioma.
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Affiliation(s)
- Pamela E Blackshear
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA Integrated Laboratory Systems, Inc., Research Triangle Park, North Carolina, USA
| | - Arun R Pandiri
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina, USA
| | - Hiroaki Nagai
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Sachin Bhusari
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Hue-Hua Hong
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Thai-Vu T Ton
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Natasha P Clayton
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Michael Wyde
- Experimental Toxicology Group, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Keith R Shockley
- Biostatistics Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Shyamal D Peddada
- Biostatistics Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Kevin E Gerrish
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Robert C Sills
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Mark J Hoenerhoff
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
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Lin CY, Lin LY, Chen YC, Wen LL, Chien KL, Sung FC, Chen PC, Su TC. Association between measurements of thyroid function and the acrylamide metabolite N-Acetyl-S-(propionamide)-cysteine in adolescents and young adults. ENVIRONMENTAL RESEARCH 2015; 136:246-52. [PMID: 25460643 DOI: 10.1016/j.envres.2014.08.043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 08/21/2014] [Accepted: 08/29/2014] [Indexed: 05/21/2023]
Abstract
Acrylamide is present in mainstream cigarette smoke and in some foods prepared at high temperatures. Animal studies have shown that acrylamide exposure alters thyroid function; however, it is not known if this also occurs in humans. The study examined the association between the urinary levels of the acrylamide metabolite and serum thyroid measures in adolescents and young adults. We recruited 793 subjects (mean age, 21.3 years; range, 12-30 years) from a population-based sample of Taiwanese adolescents and young adults to determine if the urinary levels of the acrylamide metabolite N-acetyl-S-(propionamide)-cysteine (AAMA) and the 6 serum thyroid measures are associated. The mean (SD) AAMA were 76.54 (76.42) µg/L. Linear regression analyzes showed a 1-unit increase in natural log AAMA was significantly associated with a decrease in serum free thyroxine (T4) (ng/dL) (β=-0.041, SE=0.013, p=0.001) after controlling for covariates. Subpopulation analyzes showed AAMA and free T4 were significantly associated with females, age 20-30 years, non-current smokers, and non-alcohol consumers. In conclusion, higher urinary AAMA concentrations were associated with decreased levels of free T4 in this cohort. Further studies are warranted to determine if there is a causal relationship between acrylamide exposure and thyroid function.
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Affiliation(s)
- Chien-Yu Lin
- Department of Internal Medicine, En Chu Kong Hospital, New Taipei City 237, Taiwan; School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan
| | - Lian-Yu Lin
- Department of Internal Medicine and Cardiovascular Center, National Taiwan University Hospital, Taipei 100, Taiwan
| | - Yu-Chuan Chen
- Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei 100, Taiwan
| | - Li-Li Wen
- Department of Clinical Laboratory, En Chu Kong Hospital, New Taipei City 237, Taiwan
| | - Kuo-Liong Chien
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei 10002, Taiwan
| | - Fung-Chang Sung
- Institute of Environmental Health, College of Public Health, China Medical University, Taichung 404, Taiwan
| | - Pau-Chung Chen
- Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei 100, Taiwan; Department of Public Health, College of Public Health, National Taiwan University, Taipei 10002, Taiwan; Department of Environmental and Occupational Medicine, National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei 10002, Taiwan.
| | - Ta-Chen Su
- Department of Internal Medicine and Cardiovascular Center, National Taiwan University Hospital, Taipei 100, Taiwan; Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei 100, Taiwan.
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Dourson M, Reichard J, Nance P, Burleigh-Flayer H, Parker A, Vincent M, McConnell EE. Mode of action analysis for liver tumors from oral 1,4-dioxane exposures and evidence-based dose response assessment. Regul Toxicol Pharmacol 2014; 68:387-401. [PMID: 24491968 DOI: 10.1016/j.yrtph.2014.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 01/03/2014] [Accepted: 01/25/2014] [Indexed: 11/29/2022]
Abstract
1,4-Dioxane is found in consumer products and is used as a solvent in manufacturing. Studies in rodents show liver tumors to be consistently reported after chronic oral exposure. However, there were differences in the reporting of non-neoplastic lesions in the livers of rats and mice. In order to clarify these differences, a reread of mouse liver slides from the 1978 NCI bioassay on 1,4-dioxane in drinking water was conducted. This reread clearly identified dose-related non-neoplastic changes in the liver; specifically, a dose-related increase in the hypertrophic response of hepatocytes, followed by necrosis, inflammation and hyperplastic hepatocellular foci. 1,4-Dioxane does not cause point mutations, DNA repair, or initiation. However, it appears to promote tumors and stimulate DNA synthesis. Using EPA Guidelines (2005), the weight of the evidence suggests that 1,4-dioxane causes liver tumors in rats and mice through cytotoxicity followed by regenerative hyperplasia. Specific key events in this mode of action are identified. A Reference Dose (RfD) of 0.05mg/kgday is proposed to protect against regenerative liver hyperplasia based on a benchmark dose (BMD) approach. Based on this RfD, a maximum contaminant level goal of 350μg/L is proposed using a default relative source contribution for water of 20%.
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Affiliation(s)
- Michael Dourson
- Toxicology Excellence for Risk Assessment, 2300 Montana Ave., Suite 409, Cincinnati, OH 45211, United States
| | - John Reichard
- Toxicology Excellence for Risk Assessment, 2300 Montana Ave., Suite 409, Cincinnati, OH 45211, United States
| | - Patricia Nance
- Toxicology Excellence for Risk Assessment, 2300 Montana Ave., Suite 409, Cincinnati, OH 45211, United States.
| | | | - Ann Parker
- Toxicology Excellence for Risk Assessment, 2300 Montana Ave., Suite 409, Cincinnati, OH 45211, United States
| | - Melissa Vincent
- Toxicology Excellence for Risk Assessment, 2300 Montana Ave., Suite 409, Cincinnati, OH 45211, United States
| | - Ernest E McConnell
- ToxPath, Inc., 3028 Ethan Lane, Laurdane Est., Raleigh, NC 27613, United States
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Hogervorst JG, Fortner RT, Mucci LA, Tworoger SS, Eliassen AH, Hankinson SE, Wilson KM. Associations between dietary acrylamide intake and plasma sex hormone levels. Cancer Epidemiol Biomarkers Prev 2013; 22:2024-36. [PMID: 23983241 DOI: 10.1158/1055-9965.epi-13-0509] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The rodent carcinogen acrylamide was discovered in 2002 in commonly consumed foods. Epidemiologic studies have observed positive associations between acrylamide intake and endometrial, ovarian, and breast cancer risks, which suggest that acrylamide may have sex-hormonal effects. METHODS We cross-sectionally investigated the relationship between acrylamide intake and plasma levels of sex hormones and sex hormone-binding globulin (SHBG) among 687 postmenopausal and 1,300 premenopausal controls from nested case-control studies within the Nurses' Health Studies. RESULTS There were no associations between acrylamide and sex hormones or SHBG among premenopausal women overall or among never-smokers. Among normal-weight premenopausal women, acrylamide intake was statistically significantly positively associated with luteal total and free estradiol levels. Among postmenopausal women overall and among never-smokers, acrylamide was borderline statistically significantly associated with lower estrone sulfate levels but not with other estrogens, androgens, prolactin, or SHBG. Among normal-weight women, (borderline) statistically significant inverse associations were noted for estrone, free estradiol, estrone sulfate, DHEA, and prolactin, whereas statistically significant positive associations for testosterone and androstenedione were observed among overweight women. CONCLUSIONS Overall, this study did not show conclusive associations between acrylamide intake and sex hormones that would lend unequivocal biologic plausibility to the observed increased risks of endometrial, ovarian, and breast cancer. The association between acrylamide and sex hormones may differ by menopausal and overweight status. We recommend other studies investigate the relationship between acrylamide and sex hormones in women, specifically using acrylamide biomarkers. IMPACT The present study showed some interesting associations between acrylamide intake and sex hormones that urgently need confirmation.
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Affiliation(s)
- Janneke G Hogervorst
- Authors' Affiliations: Department of Epidemiology, GROW-School for Oncology & Developmental Biology, Maastricht University, Maastricht, the Netherlands; Department of Epidemiology, Harvard School of Public Health; Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston; and Division of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst, Massachusetts
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Ehlers A, Lenze D, Broll H, Zagon J, Hummel M, Lampen A. Dose dependent molecular effects of acrylamide and glycidamide in human cancer cell lines and human primary hepatocytes. Toxicol Lett 2013; 217:111-20. [DOI: 10.1016/j.toxlet.2012.12.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 12/18/2012] [Accepted: 12/19/2012] [Indexed: 12/08/2022]
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Kadekar S, Peddada S, Silins I, French JE, Högberg J, Stenius U. Gender differences in chemical carcinogenesis in National Toxicology Program 2-year bioassays. Toxicol Pathol 2012; 40:1160-8. [PMID: 22585941 PMCID: PMC4778959 DOI: 10.1177/0192623312446527] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Differences in cancer incidences between men and women are often explained by either differences in environmental exposures or by influences of sex hormones. However, there are few studies on intrinsic gender differences in susceptibility to chemical carcinogens. We have analyzed the National Toxicology Program (NTP) database for sex differences in rat responses to chemical carcinogens. We found that the odds that male rat bioassays were assigned a higher level of evidence than female rat bioassays was 1.69 (p < .001). Of 278 carcinogenic chemicals in the database, 201 (72%) exhibited statistical gender differences (p ≤ .05) in at least one nonreproductive organ. One hundred thirty of these 201 chemicals induced gender-specific tumors in male rats and 59 in female rats. Sixty-eight chemicals induced tumors in males but no tumors in females. Less than one third (i.e., 19 chemicals) induced tumors in females but not males. Male-specific tumors included pancreatic and skin tumors, and female-specific tumors included lung tumors. For some tumor sites, these differences in gender susceptibility can be associated with literature data on sex hormone receptor expression. In conclusion, gender-specific tumors were common. The male dominance is in line with recent human data, and the male susceptibility to carcinogens should be further studied.
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Affiliation(s)
- Sandeep Kadekar
- Institute of Environmental Medicine, Karolinska Institutet, S-17177 Stockholm, Sweden
| | - Shyamal Peddada
- National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Ilona Silins
- Institute of Environmental Medicine, Karolinska Institutet, S-17177 Stockholm, Sweden
| | - John E French
- National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Johan Högberg
- Institute of Environmental Medicine, Karolinska Institutet, S-17177 Stockholm, Sweden
| | - Ulla Stenius
- Institute of Environmental Medicine, Karolinska Institutet, S-17177 Stockholm, Sweden
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LoPachin RM, Gavin T. Molecular mechanism of acrylamide neurotoxicity: lessons learned from organic chemistry. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:1650-7. [PMID: 23060388 PMCID: PMC3548275 DOI: 10.1289/ehp.1205432] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 09/24/2012] [Indexed: 05/21/2023]
Abstract
BACKGROUND Acrylamide (ACR) produces cumulative neurotoxicity in exposed humans and laboratory animals through a direct inhibitory effect on presynaptic function. OBJECTIVES In this review, we delineate how knowledge of chemistry provided an unprecedented understanding of the ACR neurotoxic mechanism. We also show how application of the hard and soft, acids and bases (HSAB) theory led to the recognition that the α,β-unsaturated carbonyl structure of ACR is a soft electrophile that preferentially forms covalent bonds with soft nucleophiles. METHODS In vivo proteomic and in chemico studies demonstrated that ACR formed covalent adducts with highly nucleophilic cysteine thiolate groups located within active sites of presynaptic proteins. Additional research showed that resulting protein inactivation disrupted nerve terminal processes and impaired neurotransmission. DISCUSSION ACR is a type-2 alkene, a chemical class that includes structurally related electrophilic environmental pollutants (e.g., acrolein) and endogenous mediators of cellular oxidative stress (e.g., 4-hydroxy-2-nonenal). Members of this chemical family produce toxicity via a common molecular mechanism. Although individual environmental concentrations might not be toxicologically relevant, exposure to an ambient mixture of type-2 alkene pollutants could pose a significant risk to human health. Furthermore, environmentally derived type-2 alkenes might act synergistically with endogenously generated unsaturated aldehydes to amplify cellular damage and thereby accelerate human disease/injury processes that involve oxidative stress. CONCLUSIONS These possibilities have substantial implications for environmental risk assessment and were realized through an understanding of ACR adduct chemistry. The approach delineated here can be broadly applied because many toxicants of different chemical classes are electrophiles that produce toxicity by interacting with cellular proteins.
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Affiliation(s)
- Richard M LoPachin
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10467 , USA.
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Bongers ML, Hogervorst JGF, Schouten LJ, Goldbohm RA, Schouten HC, van den Brandt PA. Dietary acrylamide intake and the risk of lymphatic malignancies: the Netherlands Cohort Study on diet and cancer. PLoS One 2012; 7:e38016. [PMID: 22723843 PMCID: PMC3377662 DOI: 10.1371/journal.pone.0038016] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 05/02/2012] [Indexed: 11/25/2022] Open
Abstract
Background Acrylamide, a probable human carcinogen, is present in many everyday foods. Since the finding of its presence in foods in 2002, epidemiological studies have found some suggestive associations between dietary acrylamide exposure and the risk of various cancers. The aim of this prospective study is to investigate for the first time the association between dietary acrylamide intake and the risk of several histological subtypes of lymphatic malignancies. Methods The Netherlands Cohort Study on diet and cancer includes 120,852 men and women followed-up since September 1986. The number of person years at risk was estimated by using a random sample of participants from the total cohort that was chosen at baseline (n = 5,000). Acrylamide intake was estimated from a food frequency questionnaire combined with acrylamide data for Dutch foods. Hazard ratios (HRs) were calculated for acrylamide intake as a continuous variable as well as in categories (quintiles and tertiles), for men and women separately and for never-smokers, using multivariable-adjusted Cox proportional hazards models. Results After 16.3 years of follow-up, 1,233 microscopically confirmed cases of lymphatic malignancies were available for multivariable-adjusted analysis. For multiple myeloma and follicular lymphoma, HRs for men were 1.14 (95% CI: 1.01, 1.27) and 1.28 (95% CI: 1.03, 1.61) per 10 µg acrylamide/day increment, respectively. For never-smoking men, the HR for multiple myeloma was 1.98 (95% CI: 1.38, 2.85). No associations were observed for women. Conclusion We found indications that acrylamide may increase the risk of multiple myeloma and follicular lymphoma in men. This is the first epidemiological study to investigate the association between dietary acrylamide intake and the risk of lymphatic malignancies, and more research into these observed associations is warranted.
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Affiliation(s)
- Mathilda L. Bongers
- Department of Epidemiology, School for Oncology and Developmental Biology (GROW), Maastricht University Medical Centre +, Maastricht, The Netherlands
| | - Janneke G. F. Hogervorst
- Department of Epidemiology, School for Oncology and Developmental Biology (GROW), Maastricht University Medical Centre +, Maastricht, The Netherlands
- * E-mail:
| | - Leo J. Schouten
- Department of Epidemiology, School for Oncology and Developmental Biology (GROW), Maastricht University Medical Centre +, Maastricht, The Netherlands
| | - R. Alexandra Goldbohm
- Division Quality of Life, Department of Prevention and Health, Netherlands Organisation for Applied Scientific Research (TNO), Leiden, The Netherlands
| | - Harry C. Schouten
- Division of Hematology, Department of Internal Medicine, Maastricht University Medical Centre +, Maastricht, The Netherlands
| | - Piet A. van den Brandt
- Department of Epidemiology, School for Oncology and Developmental Biology (GROW), Maastricht University Medical Centre +, Maastricht, The Netherlands
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Maier A, Kohrman-Vincent M, Hertzberg R, Allen B, Haber LT, Dourson M. Critical review of dose-response options for F344 rat mammary tumors for acrylamide - additional insights based on mode of action. Food Chem Toxicol 2012; 50:1763-75. [PMID: 22366097 DOI: 10.1016/j.fct.2012.02.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 01/30/2012] [Accepted: 02/05/2012] [Indexed: 11/30/2022]
Abstract
Previous risk assessment reviews analyzed the potential for dietary acrylamide to increase breast cancer risk. Here, we critically review acrylamide animal bioassay data on mammary tumors for human relevance. We applied a systematic evaluation using reasonable standards of scientific certainty and a systematic weight of evidence (WOE) approach to evaluate several hypothesized modes of action (MOA), including (1) genotoxicity related to glycidamide formation and oxidative stress, (2) endocrine effects due to age-related hyperprolactinemia or secondary to neurotoxicity, and (3) epigenetic effects. We conclude that the appropriate approach for low-dose extrapolation of the rat mammary tumors can be narrowed to two options: (1) linear low-dose extrapolation (i.e., based on a MOA of mutagenicity from direct DNA interaction) from a point of departure (POD) for the combined incidence of adenomas and adenocarcinomas, since these tumor types are related; or (2) non-linear extrapolation, using uncertainty factors to estimate a Reference Dose (RfD) from a POD for tumor promotion derived using the combined fibroadenoma, adenoma and adenocarcinoma data. Non-linear extrapolation is used in the latter approach because these combined tumor types are unlikely to be exclusively caused by mutagenicity. Comparison of the WOE for each alternative MOA indicates that a non-linear approach (option 2) is more appropriate for evaluation of acrylamide-induced mammary tumors; a linear approach (option 1) is shown for comparison.
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Affiliation(s)
- Andrew Maier
- Toxicology Excellence for Risk Assessment, Cincinnati, OH 45211, United States.
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15
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Tardiff RG, Gargas ML, Kirman CR, Leigh Carson M, Sweeney LM. Estimation of safe dietary intake levels of acrylamide for humans. Food Chem Toxicol 2010; 48:658-67. [DOI: 10.1016/j.fct.2009.11.048] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 11/24/2009] [Indexed: 01/23/2023]
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