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Hertzberg RC, Teuschler LK, McDonald A, Sey YM, Simmons JE. Evaluation of the Interaction-Based Hazard Index Formula Using Data on Four Trihalomethanes from U.S. EPA's Multiple-Purpose Design Study. TOXICS 2024; 12:305. [PMID: 38787084 PMCID: PMC11125920 DOI: 10.3390/toxics12050305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 04/12/2024] [Accepted: 04/17/2024] [Indexed: 05/25/2024]
Abstract
The interaction-based hazard index (HIINT), a mixtures approach to characterizing toxicologic interactions, is demonstrated and evaluated by statistically analyzing data on four regulated trihalomethanes (THMs). These THMs were the subject of a multipurpose toxicology study specifically designed to evaluate the HIINT formula. This HIINT evaluation uses single, binary and quaternary mixture THM data. While this research is considered preliminary, the results provide insights on the application of HIINT when toxicology mixture data are available and on improvements to the method. The results for relative liver weight show the HIINT was generally not conservative but did adjust the additive hazard index (HI) in the correct direction, predicting greater than dose-additivity, as seen in the mixture data. For the liver serum enzyme endpoint alanine aminotransferase, the results were mixed, with some indices giving an estimated effective dose lower than the observed mixture effective dose and others higher; in general, the HIINT adjusted the HI in the correct direction, predicting less than dose-additivity. In addition, a methodological improvement was made in the calculation of maximum interaction magnitude. Suggested refinements to the HIINT included mixture-specific replacements for default parameter values and approaches for supplementing the usual qualitative discussions of uncertainty with numerical descriptions.
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Affiliation(s)
| | | | - Anthony McDonald
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Yusupha Mahtarr Sey
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Jane Ellen Simmons
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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Teuschler LK, Hertzberg RC, McDonald A, Sey YM, Simmons JE. Evaluation of a Proportional Response Addition Approach to Mixture Risk Assessment and Predictive Toxicology Using Data on Four Trihalomethanes from the U.S. EPA's Multiple-Purpose Design Study. TOXICS 2024; 12:240. [PMID: 38668462 PMCID: PMC11053411 DOI: 10.3390/toxics12040240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 03/16/2024] [Accepted: 03/19/2024] [Indexed: 04/29/2024]
Abstract
In this study, proportional response addition (Prop-RA), a model for predicting response from chemical mixture exposure, is demonstrated and evaluated by statistically analyzing data on all possible binary combinations of the four regulated trihalomethanes (THMs). These THMs were the subject of a multipurpose toxicology study specifically designed to evaluate Prop-RA. The experimental design used a set of doses common to all components and mixtures, providing hepatotoxicity data on the four single THMs and the binary combinations. In Prop-RA, the contribution of each component to mixture toxicity is proportional to its fraction in the mixture based on its response at the total mixture dose. The primary analysis consisted of 160 evaluations. Statistically significant departures from the Prop-RA prediction were found for seven evaluations, with three predications that were greater than and four that were less than the predicted response; interaction magnitudes (n-fold difference in response vs. prediction) ranged from 1.3 to 1.4 for the former and 2.6 to 3.8 for the latter. These predictions support the idea that Prop-RA works best with chemicals where the effective dose ranges overlap. Prop-RA does not assume the similarity of toxic action or independence, but it can be applied to a mixture of components that affect the same organ/system, with perhaps unknown toxic modes of action.
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Affiliation(s)
| | | | - Anthony McDonald
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Yusupha Mahtarr Sey
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Jane Ellen Simmons
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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Liu J, Gibb M, Pradhan SH, Sayes CM. Synergistic cytotoxicity of bromoacetic acid and three emerging bromophenolic disinfection byproducts against human intestinal and neuronal cells. CHEMOSPHERE 2022; 287:131794. [PMID: 34438205 DOI: 10.1016/j.chemosphere.2021.131794] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/28/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
Halogenated disinfection byproducts (halo-DBPs) are drinking water contaminants of great public health concern. Nine haloaliphatic DBPs have been regulated by the U.S. Environmental Protection Agency and various halophenolic compounds have been identified as emerging DBPs. In this study, we evaluated the cytotoxic interactions of the regulated bromoacetic acid and three emerging bromophenolic DBPs, i.e., 2,4,6-tribromophenol, 3,5-dibromo-4-hydroxybenzoic acid, and 3,5-dibromo-4-hydroxybenzaldehyde. Cytotoxicity was measured for each DBP individually as well as each of their mixtures using in vitro human epithelial colorectal adenocarcinoma (Caco-2) and neuroblastoma (SH-SY5Y) cells. Concentration addition (CA) model and isobolographic analysis were employed to characterize the interactions among the DBPs. Our results show that the cytotoxicity of four bromo-DBPs against both cell-types followed the descending rank order of bromoacetic acid > 2,4,6-tribromophenol > 3,5-dibromo-4-hydroxybenzaldehyde > 3,5-dibromo-4-hydroxybenzoic acid. Compared with the toxicity data in literature, our finding that bromoacetic acid showed higher cytotoxicity than bromophenolic DBPs was consistent with the results from Chinese hamster ovary cells (a commonly used in vitro model of DBP toxicological studies); but different from the results obtained from in vivo biological models. Significantly, with CA model prediction, we found that mixtures of four bromo-DBPs exhibited synergistic cytotoxic effects on both human cell types. Isobolographic analysis of binary DBP mixtures revealed that, for Caco-2 cells, bromoacetic acid, 2,4,6-tribromophenol, and 3,5-dibromo-4-hydroxybenzoic acid induced synergism; for SH-SY5Y cells, bromoacetic acid induced synergism with all three bromophenolic DBPs. The production of reactive oxidative species (ROS) induced by DBP mixtures could be an important reason for the synergistic cytotoxicity.
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Affiliation(s)
- Jiaqi Liu
- Department of Environmental Science, Baylor University, Waco, TX, 76798, USA.
| | - Matthew Gibb
- Department of Environmental Science, Baylor University, Waco, TX, 76798, USA
| | - Sahar H Pradhan
- Department of Environmental Science, Baylor University, Waco, TX, 76798, USA
| | - Christie M Sayes
- Department of Environmental Science, Baylor University, Waco, TX, 76798, USA.
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Goodrum PE, Anderson JK, Luz AL, Ansell GK. Application of a Framework for Grouping and Mixtures Toxicity Assessment of PFAS: A Closer Examination of Dose-Additivity Approaches. Toxicol Sci 2021; 179:262-278. [PMID: 32735321 PMCID: PMC7846094 DOI: 10.1093/toxsci/kfaa123] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Environmental occurrence and biomonitoring data for per- and polyfluoroalkyl substances (PFAS) demonstrate that humans are exposed to mixtures of PFAS. This article presents a new and systematic analysis of available PFAS toxicity study data using a tiered mixtures risk assessment framework consistent with United States and international mixtures guidance. The lines of evidence presented herein include a critique of whole mixture toxicity studies and analysis of dose-response models based on data from subchronic oral toxicity studies in rats. Based on available data to-date, concentration addition and relative potency factor methods are found to be inappropriate due to differences among sensitive effects and target organ potencies and noncongruent dose-response curves for the same effect endpoints from studies using the same species and protocols. Perfluorooctanoic acid and perfluorooctane sulfonic acid lack a single mode of action or molecular initiating event and our evaluation herein shows they also have noncongruent dose-response curves. Dose-response curves for long-chain perfluoroalkyl sulfonic acids (PFSAs) also significantly differ in shapes of the curves from short-chain PFSAs and perfluoroalkyl carboxylic acids evaluated, and additional differences are apparent when curves are evaluated based on internal or administered dose. Following well-established guidance, the hazard index method applied to perfluoroalkyl carboxylic acids and PFSAs grouped separately is the most appropriate approach for conducting a screening level risk assessment for nonpolymeric PFAS mixtures, given the current state-of-the science. A clear presentation of assumptions, uncertainties, and data gaps is needed before dose-additivity methods, including hazard index , are used to support risk management decisions. Adverse outcome pathway(s) and mode(s) of action information for perfluorooctanoic acid and perfluorooctane sulfonic acid and for other nonpolymer PFAS are key data gaps precluding more robust mixtures methods. These findings can guide the prioritization of future studies on single chemical and whole mixture toxicity studies.
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Jacob RS, de Souza Santos LV, d'Auriol M, Lebron YAR, Moreira VR, Lange LC. Diazepam, metformin, omeprazole and simvastatin: a full discussion of individual and mixture acute toxicity. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1062-1071. [PMID: 32588236 DOI: 10.1007/s10646-020-02239-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/06/2020] [Indexed: 06/11/2023]
Abstract
High consumption of drugs, combined with their presence in the environment, raises concerns about its consequences. Even though researches are often engaged in analyzing substances separately, that is not the environmental reality. Therefore, the aim of this study was to investigate the acute toxicity of the pharmaceuticals simvastatin, metformin, omeprazole and diazepam, and all possible mixtures between them, to the organism Aliivibrio fischeri, verifying possible synergistic or antagonistic effects and assessing byproducts formation. In terms of individual toxicity, omeprazole is the most toxic of the active ingredients, followed by simvastatin, diazepam and, finally, metformin. When the toxicity of mixtures was tested, synergism, antagonism and hormesis were perceived, most probably generated due to byproducts formation. Moreover, it was observed that even when compounds are at concentrations below the non-observed effect concentration (NOEC), there may be toxicity to the mixture. Hence, this work points to the urgent need for more studies involving mixtures, since chemicals are subject to interactions and modifications, can mix, and potentiate or nullify the toxic effect of each other.
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Affiliation(s)
- Raquel Sampaio Jacob
- Sanitation and Environmental Engineering Department, School of Engineering, Federal University of Minas Gerais, Avenue Antônio Carlos, 6627, Campus Pampulha, MG, Brazil.
- Civil Engineering Department, Pontifical Catholic University of Minas Gerais, Belo Horizonte, MG, ZIP 30.535-901, Brazil.
| | - Lucilaine Valéria de Souza Santos
- Sanitation and Environmental Engineering Department, School of Engineering, Federal University of Minas Gerais, Avenue Antônio Carlos, 6627, Campus Pampulha, MG, Brazil
- Chemical Engineering Department, Pontifical Catholic University of Minas Gerais, Belo Horizonte, MG, ZIP 30.535-901, Brazil
| | - Mirna d'Auriol
- Sanitation and Environmental Engineering Department, School of Engineering, Federal University of Minas Gerais, Avenue Antônio Carlos, 6627, Campus Pampulha, MG, Brazil
| | - Yuri Abner Rocha Lebron
- Sanitation and Environmental Engineering Department, School of Engineering, Federal University of Minas Gerais, Avenue Antônio Carlos, 6627, Campus Pampulha, MG, Brazil
| | - Victor Rezende Moreira
- Sanitation and Environmental Engineering Department, School of Engineering, Federal University of Minas Gerais, Avenue Antônio Carlos, 6627, Campus Pampulha, MG, Brazil
| | - Liséte Celina Lange
- Sanitation and Environmental Engineering Department, School of Engineering, Federal University of Minas Gerais, Avenue Antônio Carlos, 6627, Campus Pampulha, MG, Brazil
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Hayes AW, Li R, Hoeng J, Iskandar A, Peistch MC, Dourson ML. New approaches to risk assessment of chemical mixtures. TOXICOLOGY RESEARCH AND APPLICATION 2019. [DOI: 10.1177/2397847318820768] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
| | - Roman Li
- Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Dübendorf, Switzerland
- Philip Morris International (PMI) Research & Development, Neuchâtel, Switzerland
| | - Julia Hoeng
- Philip Morris International (PMI) Research & Development, Neuchâtel, Switzerland
| | - Anita Iskandar
- Philip Morris International (PMI) Research & Development, Neuchâtel, Switzerland
| | - Manuel C Peistch
- Philip Morris International (PMI) Research & Development, Neuchâtel, Switzerland
| | - Michael L Dourson
- Toxicology Excellence for Risk Assessment (TERA), Cincinnati, OH, USA
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Dawson DA, Guinn D, Pöch G. Evaluation of time-dependent toxicity and combined effects for a series of mono-halogenated acetonitrile-containing binary mixtures. Toxicol Rep 2016; 3:572-583. [PMID: 28090437 PMCID: PMC5223777 DOI: 10.1016/j.toxrep.2016.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Mixture and time-dependent toxicity (TDT) was assessed for a series of mono-halogenated acetonitrile-containing combinations. Inhibition of bioluminescence in Aliivibrio fischeri was measured after 15, 30 and 45-min of exposure. Concentration-response (x/y) curves were determined for each chemical alone at each timepoint, and used to develop predicted x/y curves for the dose-addition and independence models of combined effect. The x/y data for each binary mixture was then evaluated against the predicted mixture curves. Two metrics of mixture toxicity were calculated per combined effect model: (1) an EC50-based dose-addition (AQ) or independence (IQ) quotient and (2) the mixture/dose-addition (MX/DA) and mixture/independence (MX/I) metrics. For each single chemical and mixture tested, TDT was also calculated. After 45-min of exposure, 25 of 67 mixtures produced curves that were consistent with dose-addition using the MX/DA metric, with the other 42 being less toxic than predicted by MX/DA. Some mixtures had toxicity that was consistent with both dose-addition and independence. In general, those that were less toxic than predicted for dose-addition were also less toxic than predicted for independence. Of the 25 combinations that were consistent with dose-addition, 22 (88%) mixtures contained chemicals for which the individual TDT values were both >80%. In contrast, of the 42 non-dose-additive combinations, only 2 (4.8%) of the mixtures had both chemicals with individual TDT values >80%. The results support previous findings that TDT determinations can be useful for predicting chemical mixture toxicity.
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Affiliation(s)
- Douglas A Dawson
- Department of Biology/Toxicology, Ashland University, Ashland, OH, USA
| | - Daphne Guinn
- Department of Biology/Toxicology, Ashland University, Ashland, OH, USA
| | - Gerald Pöch
- Department of Pharmacology and Toxicology, University of Graz, Graz, Austria
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Toxicology: a discipline in need of academic anchoring--the point of view of the German Society of Toxicology. Arch Toxicol 2015; 89:1881-93. [PMID: 26314262 PMCID: PMC4572062 DOI: 10.1007/s00204-015-1577-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 08/10/2015] [Indexed: 12/29/2022]
Abstract
The paper describes the importance of toxicology as a discipline, its past achievements, current scientific challenges, and future development. Toxicological expertise is instrumental in the reduction of human health risks arising from chemicals and drugs. Toxicological assessment is needed to evaluate evidence and arguments, whether or not there is a scientific base for concern. The immense success already achieved by toxicological work is exemplified by reduced pollution of air, soil, water, and safer working places. Predominantly predictive toxicological testing is derived from the findings to assess risks to humans and the environment. Assessment of the adversity of molecular effects (including epigenetic effects), the effects of mixtures, and integration of exposure and biokinetics into in vitro testing are emerging challenges for toxicology. Toxicology is a translational science with its base in fundamental science. Academic institutions play an essential part by providing scientific innovation and education of young scientists.
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Le Magueresse-Battistoni B, Vidal H, Naville D. Lifelong consumption of low-dosed food pollutants and metabolic health. J Epidemiol Community Health 2014; 69:512-5. [PMID: 25472636 DOI: 10.1136/jech-2014-203913] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Brigitte Le Magueresse-Battistoni
- Laboratoire de Recherche en Cardiovasculaire, Métabolisme, Diabétologie et Nutrition, CarMeN INSERM U1060, Lyon-1 University, INRA UMR1397, INSA-Lyon, Lyon, France
| | - Hubert Vidal
- Laboratoire de Recherche en Cardiovasculaire, Métabolisme, Diabétologie et Nutrition, CarMeN INSERM U1060, Lyon-1 University, INRA UMR1397, INSA-Lyon, Lyon, France
| | - Danielle Naville
- Laboratoire de Recherche en Cardiovasculaire, Métabolisme, Diabétologie et Nutrition, CarMeN INSERM U1060, Lyon-1 University, INRA UMR1397, INSA-Lyon, Lyon, France
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Dawson DA, Allen EMG, Allen JL, Baumann HJ, Bensinger HM, Genco N, Guinn D, Hull MW, Il'Giovine ZJ, Kaminski CM, Peyton JR, Schultz TW, Pöch G. Time-dependence in mixture toxicity prediction. Toxicology 2014; 326:153-63. [PMID: 25446331 DOI: 10.1016/j.tox.2014.10.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 10/26/2014] [Accepted: 10/28/2014] [Indexed: 01/24/2023]
Abstract
The value of time-dependent toxicity (TDT) data in predicting mixture toxicity was examined. Single chemical (A and B) and mixture (A+B) toxicity tests using Microtox(®) were conducted with inhibition of bioluminescence (Vibrio fischeri) being quantified after 15, 30 and 45-min of exposure. Single chemical and mixture tests for 25 sham (A1:A2) and 125 true (A:B) combinations had a minimum of seven duplicated concentrations with a duplicated control treatment for each test. Concentration/response (x/y) data were fitted to sigmoid curves using the five-parameter logistic minus one parameter (5PL-1P) function, from which slope, EC25, EC50, EC75, asymmetry, maximum effect, and r(2) values were obtained for each chemical and mixture at each exposure duration. Toxicity data were used to calculate percentage-based TDT values for each individual chemical and mixture of each combination. Predicted TDT values for each mixture were calculated by averaging the TDT values of the individual components and regressed against the observed TDT values obtained in testing, resulting in strong correlations for both sham (r(2)=0.989, n=25) and true mixtures (r(2)=0.944, n=125). Additionally, regression analyses confirmed that observed mixture TDT values calculated for the 50% effect level were somewhat better correlated with predicted mixture TDT values than at the 25 and 75% effect levels. Single chemical and mixture TDT values were classified into five levels in order to discern trends. The results suggested that the ability to predict mixture TDT by averaging the TDT of the single agents was modestly reduced when one agent of the combination had a positive TDT value and the other had a minimal or negative TDT value.
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Affiliation(s)
- Douglas A Dawson
- Department of Biology/Toxicology, Ashland University, Ashland, OH 44805, USA.
| | - Erin M G Allen
- Department of Biology/Toxicology, Ashland University, Ashland, OH 44805, USA
| | - Joshua L Allen
- Department of Biology/Toxicology, Ashland University, Ashland, OH 44805, USA
| | - Hannah J Baumann
- Department of Biology/Toxicology, Ashland University, Ashland, OH 44805, USA
| | - Heather M Bensinger
- Department of Biology/Toxicology, Ashland University, Ashland, OH 44805, USA
| | - Nicole Genco
- Department of Biology/Toxicology, Ashland University, Ashland, OH 44805, USA
| | - Daphne Guinn
- Department of Biology/Toxicology, Ashland University, Ashland, OH 44805, USA
| | - Michael W Hull
- Department of Biology/Toxicology, Ashland University, Ashland, OH 44805, USA
| | | | - Chelsea M Kaminski
- Department of Biology/Toxicology, Ashland University, Ashland, OH 44805, USA
| | - Jennifer R Peyton
- Department of Biology/Toxicology, Ashland University, Ashland, OH 44805, USA
| | - T Wayne Schultz
- Department of Comparative Medicine, College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996, USA
| | - Gerald Pöch
- Department of Pharmacology and Toxicology, University of Graz, A-8010 Graz, Austria
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