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Zurlinden TJ, Reisfeld B. A Novel Method for the Development of Environmental Public Health Indicators and Benchmark Dose Estimation Using a Health-Based End Point for Chlorpyrifos. ENVIRONMENTAL HEALTH PERSPECTIVES 2018; 126:047009. [PMID: 29681141 PMCID: PMC6071752 DOI: 10.1289/ehp1743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 02/04/2018] [Accepted: 03/12/2018] [Indexed: 05/06/2023]
Abstract
BACKGROUND Organophosphorus (OP) compounds are the most widely used group of insecticides in the world. Risk assessments for these chemicals have focused primarily on 10% inhibition of acetylcholinesterase in the brain as the critical metric of effect. Aside from cholinergic effects resulting from acute exposure, many studies suggest a linkage between cognitive deficits and long-term OP exposure. OBJECTIVE In this proof-of-concept study, we focused on one of the most widely used OP insecticides in the world, chlorpyrifos (CPF), and utilized an existing physiologically based pharmacokinetic (PBPK) model and a novel pharmacodynamic (PD) dose-response model to develop a point of departure benchmark dose estimate for cognitive deficits following long-term, low-dose exposure to this chemical in rodents. METHODS Utilizing a validated PBPK/PD model for CPF, we generated a database of predicted biomarkers of exposure and internal dose metrics in both rat and human. Using simulated peak brain CPF concentrations, we developed a dose-response model to predict CPF-induced spatial memory deficits and correlated these changes to relevant biomarkers of exposure to derive a benchmark dose specific to neurobehavioral changes. We extended these cognitive deficit predictions to humans and simulated corresponding exposures using a model parameterized for humans. RESULTS Results from this study indicate that the human-equivalent benchmark dose (BMD) based on a 15% cognitive deficit as an end point is lower than that using the present threshold for 10% brain AChE inhibition. This predicted human-equivalent subchronic BMD threshold compares to occupational exposure levels determined from biomarkers of exposure and corresponds to similar exposure conditions where deficits in cognition are observed. CONCLUSIONS Quantitative PD models based on neurobehavioral testing in animals offer an important addition to the methodologies used for establishing useful environmental public health indicators and BMDs, and predictions from such models could help inform the human health risk assessment for chlorpyrifos. https://doi.org/10.1289/EHP1743.
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Affiliation(s)
- Todd J Zurlinden
- Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO, USA
| | - Brad Reisfeld
- Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO, USA
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA
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Raies AB, Bajic VB. In silico toxicology: computational methods for the prediction of chemical toxicity. WILEY INTERDISCIPLINARY REVIEWS. COMPUTATIONAL MOLECULAR SCIENCE 2016; 6:147-172. [PMID: 27066112 PMCID: PMC4785608 DOI: 10.1002/wcms.1240] [Citation(s) in RCA: 339] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 10/27/2015] [Accepted: 11/10/2015] [Indexed: 01/08/2023]
Abstract
Determining the toxicity of chemicals is necessary to identify their harmful effects on humans, animals, plants, or the environment. It is also one of the main steps in drug design. Animal models have been used for a long time for toxicity testing. However, in vivo animal tests are constrained by time, ethical considerations, and financial burden. Therefore, computational methods for estimating the toxicity of chemicals are considered useful. In silico toxicology is one type of toxicity assessment that uses computational methods to analyze, simulate, visualize, or predict the toxicity of chemicals. In silico toxicology aims to complement existing toxicity tests to predict toxicity, prioritize chemicals, guide toxicity tests, and minimize late-stage failures in drugs design. There are various methods for generating models to predict toxicity endpoints. We provide a comprehensive overview, explain, and compare the strengths and weaknesses of the existing modeling methods and algorithms for toxicity prediction with a particular (but not exclusive) emphasis on computational tools that can implement these methods and refer to expert systems that deploy the prediction models. Finally, we briefly review a number of new research directions in in silico toxicology and provide recommendations for designing in silico models. WIREs Comput Mol Sci 2016, 6:147-172. doi: 10.1002/wcms.1240 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Arwa B Raies
- King Abdullah University of Science and Technology (KAUST) Computational Bioscience Research Centre (CBRC), Computer, Electrical and Mathematical Sciences and Engineering Division (CEMSE) Thuwal Saudi Arabia
| | - Vladimir B Bajic
- King Abdullah University of Science and Technology (KAUST) Computational Bioscience Research Centre (CBRC), Computer, Electrical and Mathematical Sciences and Engineering Division (CEMSE) Thuwal Saudi Arabia
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Joas A, Knudsen LE, Kolossa-Gehring M, Sepai O, Casteleyn L, Schoeters G, Angerer J, Castaño A, Aerts D, Biot P, Horvat M, Bloemen L, Reis MF, Lupsa IR, Katsonouri A, Cerna M, Berglund M, Crettaz P, Rudnai P, Halzlova K, Mulcahy M, Gutleb AC, Fischer ME, Becher G, Fréry N, Jensen G, Van Vliet L, Koch HM, Den Hond E, Fiddicke U, Esteban M, Exley K, Schwedler G, Seiwert M, Ligocka D, Hohenblum P, Kyrtopoulos S, Botsivali M, DeFelip E, Guillou C, Reniero F, Grazuleviciene R, Veidebaum T, Mørck TA, Nielsen JKS, Jensen JF, Rivas TC, Sanchez J, Koppen G, Smolders R, Kozepesy S, Hadjipanayis A, Krskova A, Mannion R, Jakubowski M, Fucic JA, Pereira-Miguel J, Gurzau AE, Jajcaj M, Mazej D, Tratnik JS, Lehmann A, Larsson K, Dumez B, Joas R. Policy recommendations and cost implications for a more sustainable framework for European human biomonitoring surveys. ENVIRONMENTAL RESEARCH 2015; 141:42-57. [PMID: 25526891 DOI: 10.1016/j.envres.2014.10.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 10/08/2014] [Accepted: 10/09/2014] [Indexed: 06/04/2023]
Abstract
The potential of Human Biomonitoring (HBM) in exposure characterisation and risk assessment is well established in the scientific HBM community and regulatory arena by many publications. The European Environment and Health Strategy as well as the Environment and Health Action Plan 2004-2010 of the European Commission recognised the value of HBM and the relevance and importance of coordination of HBM programmes in Europe. Based on existing and planned HBM projects and programmes of work and capabilities in Europe the Seventh Framework Programme (FP 7) funded COPHES (COnsortium to Perform Human Biomonitoring on a European Scale) to advance and improve comparability of HBM data across Europe. The pilot study protocol was tested in 17 European countries in the DEMOCOPHES feasibility study (DEMOnstration of a study to COordinate and Perform Human biomonitoring on a European Scale) cofunded (50%) under the LIFE+ programme of the European Commission. The potential of HBM in supporting and evaluating policy making (including e.g. REACH) and in awareness raising on environmental health, should significantly advance the process towards a fully operational, continuous, sustainable and scientifically based EU HBM programme. From a number of stakeholder activities during the past 10 years and the national engagement, a framework for sustainable HBM structure in Europe is recommended involving national institutions within environment, health and food as well as European institutions such as ECHA, EEA, and EFSA. An economic frame with shared cost implications for national and European institutions is suggested benefitting from the capacity building set up by COPHES/DEMOCOPHES.
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Affiliation(s)
| | | | | | | | | | - Greet Schoeters
- VITO, Environmental Risks and Health Unit, Belgium; University of Antwerp, Belgium, Southern Denmark University, Denmark
| | - Jürgen Angerer
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance-Institute of the Ruhr-Universität Bochum (IPA), Germany
| | - Argelia Castaño
- Environmental Toxicology, CNSA-Instituto de Salud Carlos III, Spain
| | - Dominique Aerts
- Federal Public Service Health, Food Chain Safety and Environment, Belgium
| | - Pierre Biot
- Federal Public Service Health, Food Chain Safety and Environment, Belgium
| | | | - Louis Bloemen
- Environmental Health Sciences International, The Netherlands
| | - M Fátima Reis
- Medical Faculty of the University of Lisbon, Portugal
| | | | | | - Milena Cerna
- National Institute of Public Health, Czech Republic
| | | | | | - Peter Rudnai
- National Institute of Environmental Health, Hungary
| | | | | | - Arno C Gutleb
- Centre de Recherche Public - Gabriel Lippmann, Luxembourg
| | | | | | - Nadine Fréry
- French Institute for Public Health Surveillance, France
| | | | | | - Holger M Koch
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance-Institute of the Ruhr-Universität Bochum (IPA), Germany
| | | | | | - Marta Esteban
- Environmental Toxicology, CNSA-Instituto de Salud Carlos III, Spain
| | | | | | | | | | | | | | | | | | - Claude Guillou
- European Commission, Joint Research Centre (JRC), Institute for Health and Consumer Protection (IHCP), Italy
| | - Fabiano Reniero
- European Commission, Joint Research Centre (JRC), Institute for Health and Consumer Protection (IHCP), Italy
| | | | | | | | | | | | - Teresa C Rivas
- Environmental Toxicology, CNSA-Instituto de Salud Carlos III, Spain
| | - Jinny Sanchez
- Environmental Toxicology, CNSA-Instituto de Salud Carlos III, Spain
| | | | | | | | - Adamos Hadjipanayis
- Larnaca General Hospital, Ministry of Health, School of Medicine, European University of Cyprus, Cyprus
| | | | | | | | | | | | | | - Michal Jajcaj
- Urad Verejneho Zdravotnictva Slovenskej Republiky, Slovakia
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