Novel Strategy to Assess the Neurotoxicity of Organic Solvents Such as Glycol Ethers: Protocol for Combining In Vitro and In Silico Methods With Human-Controlled Exposure Experiments

BackgroundChemicals are not required to be tested systematically for their neurotoxic potency, although they may contribute to the development of several neurological diseases. The absence of systematic testing may be partially explained by the current Organisation for Econom...

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Main Authors: Nancy B Hopf, Laura Suter-Dick, Jörg Huwyler, Myriam Borgatta, Lucie Hegg, David Pamies, Hélène Paschoud, Ramya Deepthi Puligilla, Elena Reale, Sophie Werner, Marie-Gabrielle Zurich
Format: Article
Language:English
Published: JMIR Publications 2024-01-01
Series:JMIR Research Protocols
Online Access:https://www.researchprotocols.org/2024/1/e50300
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author Nancy B Hopf
Laura Suter-Dick
Jörg Huwyler
Myriam Borgatta
Lucie Hegg
David Pamies
Hélène Paschoud
Ramya Deepthi Puligilla
Elena Reale
Sophie Werner
Marie-Gabrielle Zurich
author_facet Nancy B Hopf
Laura Suter-Dick
Jörg Huwyler
Myriam Borgatta
Lucie Hegg
David Pamies
Hélène Paschoud
Ramya Deepthi Puligilla
Elena Reale
Sophie Werner
Marie-Gabrielle Zurich
author_sort Nancy B Hopf
collection DOAJ
description BackgroundChemicals are not required to be tested systematically for their neurotoxic potency, although they may contribute to the development of several neurological diseases. The absence of systematic testing may be partially explained by the current Organisation for Economic Co-operation and Development (OECD) Test Guidelines, which rely on animal experiments that are expensive, laborious, and ethically debatable. Therefore, it is important to understand the risks to exposed workers and the general population exposed to domestic products. In this study, we propose a strategy to test the neurotoxicity of solvents using the commonly used glycol ethers as a case study. ObjectiveThis study aims to provide a strategy that can be used by regulatory agencies and industries to rank solvents according to their neurotoxicity and demonstrate the use of toxicokinetic modeling to predict air concentrations of solvents that are below the no observed adverse effect concentrations (NOAECs) for human neurotoxicity determined in in vitro assays. MethodsThe proposed strategy focuses on a complex 3D in vitro brain model (BrainSpheres) derived from human-induced pluripotent stem cells (hiPSCs). This model is accompanied by in vivo, in vitro, and in silico models for the blood-brain barrier (BBB) and in vitro models for liver metabolism. The data are integrated into a toxicokinetic model. Internal concentrations predicted using this toxicokinetic model are compared with the results from in vivo human-controlled exposure experiments for model validation. The toxicokinetic model is then used in reverse dosimetry to predict air concentrations, leading to brain concentrations lower than the NOAECs determined in the hiPSC-derived 3D brain model. These predictions will contribute to the protection of exposed workers and the general population with domestic exposures. ResultsThe Swiss Centre for Applied Human Toxicology funded the project, commencing in January 2021. The Human Ethics Committee approval was obtained on November 16, 2022. Zebrafish experiments and in vitro methods started in February 2021, whereas recruitment of human volunteers started in 2022 after the COVID-19 pandemic–related restrictions were lifted. We anticipate that we will be able to provide a neurotoxicity testing strategy by 2026 and predicted air concentrations for 6 commonly used propylene glycol ethers based on toxicokinetic models incorporating liver metabolism, BBB leakage parameters, and brain toxicity. ConclusionsThis study will be of great interest to regulatory agencies and chemical industries needing and seeking novel solutions to develop human chemical risk assessments. It will contribute to protecting human health from the deleterious effects of environmental chemicals. International Registered Report Identifier (IRRID)DERR1-10.2196/50300
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spelling doaj.art-6e5ba83bc0d641c6be67270524a82d402024-01-18T13:30:32ZengJMIR PublicationsJMIR Research Protocols1929-07482024-01-0113e5030010.2196/50300Novel Strategy to Assess the Neurotoxicity of Organic Solvents Such as Glycol Ethers: Protocol for Combining In Vitro and In Silico Methods With Human-Controlled Exposure ExperimentsNancy B Hopfhttps://orcid.org/0000-0002-4490-6109Laura Suter-Dickhttps://orcid.org/0000-0002-1449-3913Jörg Huwylerhttps://orcid.org/0000-0003-1748-5676Myriam Borgattahttps://orcid.org/0000-0002-6326-0614Lucie Hegghttps://orcid.org/0009-0002-3105-9577David Pamieshttps://orcid.org/0000-0002-1224-573XHélène Paschoudhttps://orcid.org/0000-0001-5429-5148Ramya Deepthi Puligillahttps://orcid.org/0000-0002-0767-9402Elena Realehttps://orcid.org/0000-0002-0853-0693Sophie Wernerhttps://orcid.org/0009-0007-6531-2610Marie-Gabrielle Zurichhttps://orcid.org/0000-0002-3168-5968 BackgroundChemicals are not required to be tested systematically for their neurotoxic potency, although they may contribute to the development of several neurological diseases. The absence of systematic testing may be partially explained by the current Organisation for Economic Co-operation and Development (OECD) Test Guidelines, which rely on animal experiments that are expensive, laborious, and ethically debatable. Therefore, it is important to understand the risks to exposed workers and the general population exposed to domestic products. In this study, we propose a strategy to test the neurotoxicity of solvents using the commonly used glycol ethers as a case study. ObjectiveThis study aims to provide a strategy that can be used by regulatory agencies and industries to rank solvents according to their neurotoxicity and demonstrate the use of toxicokinetic modeling to predict air concentrations of solvents that are below the no observed adverse effect concentrations (NOAECs) for human neurotoxicity determined in in vitro assays. MethodsThe proposed strategy focuses on a complex 3D in vitro brain model (BrainSpheres) derived from human-induced pluripotent stem cells (hiPSCs). This model is accompanied by in vivo, in vitro, and in silico models for the blood-brain barrier (BBB) and in vitro models for liver metabolism. The data are integrated into a toxicokinetic model. Internal concentrations predicted using this toxicokinetic model are compared with the results from in vivo human-controlled exposure experiments for model validation. The toxicokinetic model is then used in reverse dosimetry to predict air concentrations, leading to brain concentrations lower than the NOAECs determined in the hiPSC-derived 3D brain model. These predictions will contribute to the protection of exposed workers and the general population with domestic exposures. ResultsThe Swiss Centre for Applied Human Toxicology funded the project, commencing in January 2021. The Human Ethics Committee approval was obtained on November 16, 2022. Zebrafish experiments and in vitro methods started in February 2021, whereas recruitment of human volunteers started in 2022 after the COVID-19 pandemic–related restrictions were lifted. We anticipate that we will be able to provide a neurotoxicity testing strategy by 2026 and predicted air concentrations for 6 commonly used propylene glycol ethers based on toxicokinetic models incorporating liver metabolism, BBB leakage parameters, and brain toxicity. ConclusionsThis study will be of great interest to regulatory agencies and chemical industries needing and seeking novel solutions to develop human chemical risk assessments. It will contribute to protecting human health from the deleterious effects of environmental chemicals. International Registered Report Identifier (IRRID)DERR1-10.2196/50300https://www.researchprotocols.org/2024/1/e50300
spellingShingle Nancy B Hopf
Laura Suter-Dick
Jörg Huwyler
Myriam Borgatta
Lucie Hegg
David Pamies
Hélène Paschoud
Ramya Deepthi Puligilla
Elena Reale
Sophie Werner
Marie-Gabrielle Zurich
Novel Strategy to Assess the Neurotoxicity of Organic Solvents Such as Glycol Ethers: Protocol for Combining In Vitro and In Silico Methods With Human-Controlled Exposure Experiments
JMIR Research Protocols
title Novel Strategy to Assess the Neurotoxicity of Organic Solvents Such as Glycol Ethers: Protocol for Combining In Vitro and In Silico Methods With Human-Controlled Exposure Experiments
title_full Novel Strategy to Assess the Neurotoxicity of Organic Solvents Such as Glycol Ethers: Protocol for Combining In Vitro and In Silico Methods With Human-Controlled Exposure Experiments
title_fullStr Novel Strategy to Assess the Neurotoxicity of Organic Solvents Such as Glycol Ethers: Protocol for Combining In Vitro and In Silico Methods With Human-Controlled Exposure Experiments
title_full_unstemmed Novel Strategy to Assess the Neurotoxicity of Organic Solvents Such as Glycol Ethers: Protocol for Combining In Vitro and In Silico Methods With Human-Controlled Exposure Experiments
title_short Novel Strategy to Assess the Neurotoxicity of Organic Solvents Such as Glycol Ethers: Protocol for Combining In Vitro and In Silico Methods With Human-Controlled Exposure Experiments
title_sort novel strategy to assess the neurotoxicity of organic solvents such as glycol ethers protocol for combining in vitro and in silico methods with human controlled exposure experiments
url https://www.researchprotocols.org/2024/1/e50300
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