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Rosenberg YJ, Garcia K, Diener J, Sullivan D, Donahue S, Mao L, Lees J, Jiang X, Urban LA, Momper JD, Ho KY, Taylor P. A single post-exposure oxime RS194B treatment rapidly reactivates acetylcholinesterase and reverses acute symptoms in macaques exposed to diethylphosphorothioate parathion and chlorpyrifos insecticides. J Neurochem 2024; 168:370-380. [PMID: 36786545 DOI: 10.1111/jnc.15777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/20/2023] [Accepted: 01/28/2023] [Indexed: 02/15/2023]
Abstract
Millions of individuals globally suffer from inadvertent, occupational or self-harm exposures from organophosphate (OP) insecticides, significantly impacting human health. Similar to nerve agents, insecticides are neurotoxins that target and inhibit acetylcholinesterase (AChE) in central and peripheral synapses in the cholinergic nervous system. Post-exposure therapeutic countermeasures generally include administration of atropine with an oxime to reactivate the OP-inhibited AChE. However, animal model studies and recent clinical trials using insecticide-poisoned individuals have shown minimal clinical benefits of the currently approved oximes and their efficacy as antidotes has been debated. Currently used oximes either reactivate poorly, do not readily cross the blood-brain barrier (BBB), or are rapidly cleared from the circulation and must be repeatedly administered. Zwitterionic oximes of unbranched and simplified structure, for example RS194B, have been developed that efficiently cross the BBB resulting in reactivation of OP-inhibited AChE and dramatic reversal of severe clinical symptoms in mice and macaques exposed to OP insecticides or nerve agents. Thus, a single IM injection of RS194B has been shown to rapidly restore blood AChE and butyrylcholinesterase (BChE) activity, reverse cholinergic symptoms, and prevent death in macaques following lethal inhaled sarin and paraoxon exposure. The present macaque studies extend these findings and assess the ability of post-exposure RS194B treatment to counteract oral poisoning by highly toxic diethylphosphorothioate insecticides such as parathion and chlorpyrifos. These OPs require conversion by P450 in the liver of the inactive thions to the active toxic oxon forms, and once again demonstrated RS194B efficacy to reactivate and alleviate clinical symptoms within 60 mins of a single IM administration. Furthermore, when delivered orally, the Tmax of RS194B at 1-2 h was in the same range as those administered IM but were maintained in the circulation for longer periods greatly facilitating the use of RS194B as a non-invasive treatment, especially in isolated rural settings.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Jeremiah D Momper
- Department of Pharmacology, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - Kwok-Yiu Ho
- Department of Pharmacology, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - Palmer Taylor
- Department of Pharmacology, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
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Ruiz-Arias MA, Medina-Díaz IM, Bernal-Hernández YY, Barrón-Vivanco BS, González-Arias CA, Romero-Bañuelos CA, Verdín-Betancourt FA, Herrera-Moreno JF, Ponce-Vélez G, Gaspar-Ramírez O, Bastidas-Bastidas PDJ, González FB, Rojas-García AE. The situation of chlorpyrifos in Mexico: a case study in environmental samples and aquatic organisms. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2023; 45:6323-6351. [PMID: 37301778 DOI: 10.1007/s10653-023-01618-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 05/11/2023] [Indexed: 06/12/2023]
Abstract
Chlorpyrifos (CPF) is one of the most commonly used organophosphate pesticides. Because CPF was described as a toxic compound without safe levels of exposure for children, certain countries in Latin America and the European Union have banned or restricted its use; however, in Mexico it is used very frequently. The aim of this study was to describe the current situation of CPF in Mexico, as well as its use, commercialization, and presence in soil, water, and aquatic organisms in an agricultural region of Mexico. Structured questionnaires were applied to pesticide retailers to determine the sales pattern of CPF (ethyl and methyl); in addition, monthly censuses were conducted with empty pesticide containers to assess the CPF pattern of use. Furthermore, samples of soil (48 samples), water (51 samples), and fish (31 samples) were collected, which were analyzed chromatographically. Descriptive statistics were performed. The results indicate that CPF was one of the most sold (3.82%) and employed OP (14.74%) during 2021. Only one soil sample was found above the CPF limit of quantification (LOQ); in contrast, all water samples had CPF levels above the LOQ (x̄ = 4614.2 ng/L of CPF). In the case of fish samples, 6.45% demonstrated the presence of methyl-CPF. In conclusion, the information obtained in this study indicates the need for constant monitoring in the area, since the presence of CPF in soil, water, and fish constitutes a threat to the health of wildlife and humans. Therefore, CPF should be banned in Mexico to avoid a serious neurocognitive health problem.
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Affiliation(s)
- Miguel Alfonso Ruiz-Arias
- Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura S/N. Col. Centro, C.P. 63000, Tepic, Nayarit, México
- Programa de Doctorado en Ciencias Biológico Agropecuarias. Área de Ciencias Ambientales, Universidad Autónoma de Nayarit, Unidad Académica de Agricultura. Km. 9 Carretera Tepic-Compostela, C.P. 63780, Xalisco, Nayarit, México
| | - Irma Martha Medina-Díaz
- Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura S/N. Col. Centro, C.P. 63000, Tepic, Nayarit, México
| | - Yael Yvette Bernal-Hernández
- Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura S/N. Col. Centro, C.P. 63000, Tepic, Nayarit, México
| | - Briscia Socorro Barrón-Vivanco
- Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura S/N. Col. Centro, C.P. 63000, Tepic, Nayarit, México
| | - Cyndia Azucena González-Arias
- Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura S/N. Col. Centro, C.P. 63000, Tepic, Nayarit, México
| | - Carlos Alberto Romero-Bañuelos
- Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura S/N. Col. Centro, C.P. 63000, Tepic, Nayarit, México
| | - Francisco Alberto Verdín-Betancourt
- Unidad Especializada de Ciencias Ambientales, CENITT, Av. Emilio M. González S/N, Ciudad del Conocimiento, Tepic, Nayarit, C.P. 63173, México
| | - José Francisco Herrera-Moreno
- Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura S/N. Col. Centro, C.P. 63000, Tepic, Nayarit, México
| | - Guadalupe Ponce-Vélez
- Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, C.P. 04510, Cd. de México, México
| | - Octavio Gaspar-Ramírez
- Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, Unidad Noreste (CIATEJ), Apodaca, N.L, C.P. 66629, Mexico
| | - Pedro de Jesús Bastidas-Bastidas
- Laboratorio Nacional para la Investigación en Inocuidad Alimentaria (Residuos de Plaguicidas), Centro de Investigación en Alimentación Y Desarrollo, A.C. (CIAD), Carretera a Eldorado Km. 5.5, Unidad Culiacán, C.P. 80110, Mexico
| | - Fernando Bejarano González
- Red de Acción Sobre Plaguicidas y Alternativas en México, A. C. (RAPAM), Amado Nervo 23, Int. 3, Col. San Juanito, C.P. 56121, Texcoco, Estado de México, Mexico
| | - Aurora Elizabeth Rojas-García
- Laboratorio de Contaminación y Toxicología Ambiental. Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura S/N. Col. Centro, C.P. 63000, Tepic, Nayarit, México.
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3
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Sammi SR, Syeda T, Conrow KD, Leung MCK, Cannon JR. Complementary biological and computational approaches identify distinct mechanisms of chlorpyrifos versus chlorpyrifos-oxon-induced dopaminergic neurotoxicity. Toxicol Sci 2023; 191:163-178. [PMID: 36269219 PMCID: PMC9887671 DOI: 10.1093/toxsci/kfac114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Organophosphate (OP) pesticides are widely used in agriculture. While acute cholinergic toxicity has been extensively studied, chronic effects on other neurons are less understood. Here, we demonstrated that the OP pesticide chlorpyrifos (CPF) and its oxon metabolite are dopaminergic neurotoxicants in Caenorhabditis elegans. CPF treatment led to inhibition of mitochondrial complex II, II + III, and V in rat liver mitochondria, while CPF-oxon did not (complex II + III and IV inhibition observed only at high doses). While the effect on C. elegans cholinergic behavior was mostly reversible with toxicant washout, dopamine-associated deficits persisted, suggesting dopaminergic neurotoxicity was irreversible. CPF reduced the mitochondrial content in a dose-dependent manner and the fat modulatory genes cyp-35A2 and cyp-35A3 were found to have a key role in CPF neurotoxicity. These findings were consistent with in vitro effects of CPF and CPF-oxon on nuclear receptor signaling and fatty acid/steroid metabolism observed in ToxCast assays. Two-way hierarchical analysis revealed in vitro effects on estrogen receptor, pregnane X receptor, and peroxisome proliferator-activated receptor gamma pathways as well as neurotoxicity of CPF, malathion, and diazinon, whereas these effects were not detected in malaoxon and diazoxon. Taken together, our study suggests that mitochondrial toxicity and metabolic effects of CPF, but not CPF-oxon, have a key role of CPF neurotoxicity in the low-dose, chronic exposure. Further mechanistic studies are needed to examine mitochondria as a common target for all OP pesticide parent compounds, because this has important implications on cumulative pesticide risk assessment.
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Affiliation(s)
- Shreesh Raj Sammi
- School of Health Sciences, Purdue University, West Lafayette, Indiana 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Tauqeerunnisa Syeda
- School of Health Sciences, Purdue University, West Lafayette, Indiana 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Kendra D Conrow
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, Arizona, USA
| | - Maxwell C K Leung
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, Arizona, USA
| | - Jason R Cannon
- School of Health Sciences, Purdue University, West Lafayette, Indiana 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana, USA
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Bart S, Short S, Jager T, Eagles EJ, Robinson A, Badder C, Lahive E, Spurgeon DJ, Ashauer R. How to analyse and account for interactions in mixture toxicity with toxicokinetic-toxicodynamic models. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 843:157048. [PMID: 35779734 DOI: 10.1016/j.scitotenv.2022.157048] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/20/2022] [Accepted: 06/25/2022] [Indexed: 05/28/2023]
Abstract
The assessment of chemical mixture toxicity is one of the major challenges in ecotoxicology. Chemicals can interact, leading to more or less effects than expected, commonly named synergism and antagonism respectively. The classic ad hoc approach for the assessment of mixture effects is based on dose-response curves at a single time point, and is limited to identifying a mixture interaction but cannot provide predictions for untested exposure durations, nor for scenarios where exposure varies in time. We here propose a new approach using toxicokinetic-toxicodynamic modelling: The General Unified Threshold model of Survival (GUTS) framework, recently extended for mixture toxicity assessment. We designed a dedicated mechanistic interaction module coupled with the GUTS mixture model to i) identify interactions, ii) test hypotheses to identify which chemical is likely responsible for the interaction, and finally iii) simulate and predict the effect of synergistic and antagonistic mixtures. We tested the modelling approach experimentally with two species (Enchytraeus crypticus and Mamestra brassicae) exposed to different potentially synergistic mixtures (composed of: prochloraz, imidacloprid, cypermethrin, azoxystrobin, chlorothalonil, and chlorpyrifos). Furthermore, we also tested the model with previously published experimental data on two other species (Bombus terrestris and Daphnia magna) exposed to pesticide mixtures (clothianidin, propiconazole, dimethoate, imidacloprid and thiacloprid) found to be synergistic or antagonistic with the classic approach. The results showed an accurate simulation of synergistic and antagonistic effects for the different tested species and mixtures. This modelling approach can identify interactions accounting for the entire time of exposure, and not only at one time point as in the classic approach, and provides predictions of the mixture effect for untested mixture exposure scenarios, including those with time-variable mixture composition.
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Affiliation(s)
- Sylvain Bart
- Department of Environment and Geography, University of York, Heslington, York YO10 5NG, UK; UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK; MO-ECO(2) (Modelling and data analyses for ecology and ecotoxicology), Paris, France.
| | - Stephen Short
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK; Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff CF10 3TL, UK
| | | | - Emily J Eagles
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK
| | - Alex Robinson
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK
| | - Claire Badder
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK; Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff CF10 3TL, UK
| | - Elma Lahive
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK
| | - David J Spurgeon
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK
| | - Roman Ashauer
- Department of Environment and Geography, University of York, Heslington, York YO10 5NG, UK; Syngenta Crop Protection AG, Basel, Switzerland
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5
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Stocco MR, Tyndale RF. Cytochrome P450 enzymes and metabolism of drugs and neurotoxins within the mammalian brain. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2022; 95:73-106. [PMID: 35953164 DOI: 10.1016/bs.apha.2022.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Cytochrome P450 enzymes (CYPs) that metabolize xenobiotics are expressed and active in the brain. These CYPs contribute to the metabolism of many centrally acting compounds, including clinically used drugs, drugs of abuse, and neurotoxins. Although CYP levels are lower in the brain than in the liver, they may influence central substrate and metabolite concentrations, which could alter resulting centrally-mediated responses to these compounds. Additionally, xenobiotic metabolizing CYPs are highly variable due to genetic polymorphisms and regulation by endogenous and xenobiotic molecules. In the brain, these CYPs are sensitive to xenobiotic induction. As a result, CYPs in the brain vary widely, including among humans, and this CYP variation may influence central metabolism and resulting response to centrally acting compounds. It has been demonstrated, using experimental manipulation of CYP activity in vivo selectively within the brain, that CYP metabolism in the brain alters central substrate and metabolite concentrations, as well as drug response and neurotoxic effects. This suggests that variability in xenobiotic metabolizing CYPs in the human brain may meaningfully contribute to individual differences in response to, and effects of, centrally acting drugs and neurotoxins. This chapter will provide an overview of CYP expression in the brain, endogenous- and xenobiotic-mediated CYP regulation, and the functional impact of CYP-mediated metabolism of drugs and neurotoxins in the brain, with a focus on experimental approaches in mice, rats, and non-human primates, and a discussion regarding the potential role of xenobiotic metabolizing CYPs in the human brain.
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Affiliation(s)
- Marlaina R Stocco
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Rachel F Tyndale
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, CAMH, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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6
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Kondakala S, Henein L, McDevitt E, Ross MK, Howell GE. Effects of chlorpyrifos on non-cholinergic toxicity endpoints in immortalized and primary rat hepatocytes under normal and hepatosteatotic conditions. Toxicol In Vitro 2022; 80:105329. [PMID: 35151815 PMCID: PMC8944201 DOI: 10.1016/j.tiv.2022.105329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/15/2021] [Accepted: 02/07/2022] [Indexed: 10/19/2022]
Abstract
Chlorpyrifos (CPS) is the most widely used organophosphate (OP) insecticide. Non-cholinergic targets of OPs include enzymes belonging to the serine hydrolase family. Carboxylesterases (Ces) are involved in detoxication of xenobiotics as well as lipid metabolism in the liver. Monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) are responsible for hydrolyzing endocannabinoids and can also be inhibited by OP compounds. However, there are no in vitro studies examining the sensitivities of these non-cholinergic endpoints following CPS exposure in the steatotic liver. Therefore, we determined the effects of CPS on these endpoints in immortalized McArdle-RH7777 (MCA) hepatoma cells and primary rat hepatocytes under normal and steatotic conditions. Ces activity was more sensitive to inhibition than MAGL or FAAH activity following exposure to the lowest CPS concentration. Additionally, Ces and MAGL activities in steatotic primary hepatocytes were less sensitive to CPS mediated inhibition than those in normal primary hepatocytes, whereas Ces inhibition was more pronounced in steatotic MCA cells. These findings suggest that steatotic conditions enhance the inhibition of hepatic serine hydrolases following exposure to CPS in an enzyme- and cell type-specific manner. CPS-mediated inhibition of these enzymes may play a part in the alterations of hepatic lipid metabolism following OP exposures.
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Affiliation(s)
- SandeepReddy Kondakala
- Department of Comparative Biomedical Sciences, 240 Wise Center Drive, P.O. Box 6100, Mississippi State, MS 39762, United States of America
| | - Lucie Henein
- Department of Comparative Biomedical Sciences, 240 Wise Center Drive, P.O. Box 6100, Mississippi State, MS 39762, United States of America
| | - Erin McDevitt
- Department of Comparative Biomedical Sciences, 240 Wise Center Drive, P.O. Box 6100, Mississippi State, MS 39762, United States of America
| | - Matthew K Ross
- Department of Comparative Biomedical Sciences, 240 Wise Center Drive, P.O. Box 6100, Mississippi State, MS 39762, United States of America
| | - George Eli Howell
- Department of Comparative Biomedical Sciences, 240 Wise Center Drive, P.O. Box 6100, Mississippi State, MS 39762, United States of America.
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Zhao S, Wesseling S, Rietjens IMCM, Strikwold M. Inter-individual variation in chlorpyrifos toxicokinetics characterized by physiologically based kinetic (PBK) and Monte Carlo simulation comparing human liver microsome and Supersome ™ cytochromes P450 (CYP)-specific kinetic data as model input. Arch Toxicol 2022; 96:1387-1409. [PMID: 35294598 PMCID: PMC9013686 DOI: 10.1007/s00204-022-03251-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 02/14/2022] [Indexed: 11/25/2022]
Abstract
The present study compares two approaches to evaluate the effects of inter-individual differences in the biotransformation of chlorpyrifos (CPF) on the sensitivity towards in vivo red blood cell (RBC) acetylcholinesterase (AChE) inhibition and to calculate a chemical-specific adjustment factor (CSAF) to account for inter-individual differences in kinetics (HKAF). These approaches included use of a Supersome™ cytochromes P450 (CYP)-based and a human liver microsome (HLM)-based physiologically based kinetic (PBK) model, both combined with Monte Carlo simulations. The results revealed that bioactivation of CPF exhibits biphasic kinetics caused by distinct differences in the Km of CYPs involved, which was elucidated by Supersome™ CYP rather than by HLM. Use of Supersome™ CYP-derived kinetic data was influenced by the accuracy of the intersystem extrapolation factors (ISEFs) required to scale CYP isoform activity of Supersome™ to HLMs. The predicted dose–response curves for average, 99th percentile and 1st percentile sensitive individuals were found to be similar in the two approaches when biphasic kinetics was included in the HLM-based approach, resulting in similar benchmark dose lower confidence limits for 10% inhibition (BMDL10) and HKAF values. The variation in metabolism-related kinetic parameters resulted in HKAF values at the 99th percentile that were slightly higher than the default uncertainty factor of 3.16. While HKAF values up to 6.9 were obtained when including also the variability in other influential PBK model parameters. It is concluded that the Supersome™ CYP-based approach appeared most adequate for identifying inter-individual variation in biotransformation of CPF and its resulting RBC AChE inhibition.
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Affiliation(s)
- Shensheng Zhao
- Division of Toxicology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - Sebastiaan Wesseling
- Division of Toxicology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Marije Strikwold
- Van Hall Larenstein University of Applied Sciences, 8901 BV, Leeuwarden, The Netherlands
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Zhu M, Gao Z, Fu Y, Qiu Y, Huang K, Zhu C, Wu Y, Zhu T, Wang Q, Yang L, Yin Y, Li P. Amorphous Selenium Nanoparticles Improve Vascular Function in Rats With Chronic Isocarbophos Poisoning via Inhibiting the Apoptosis of Vascular Endothelial Cells. Front Bioeng Biotechnol 2021; 9:673327. [PMID: 34249881 PMCID: PMC8266299 DOI: 10.3389/fbioe.2021.673327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/27/2021] [Indexed: 11/13/2022] Open
Abstract
AIM This study aimed to investigate the preventive effect and possible mechanism of amorphous selenium nanoparticles (A-SeQDs) on isocarbophos induced vascular dysfunction. METHODS A-SeQDs was made by auto redox decomposition of selenosulfate precursor. Male rats were given isocarbophos (0.5 mg/kg/2 days) by intragastric administration for 16 weeks to induce vascular dysfunction. During the course, A-SeQDs (50 mg/kg/day) was added to the water from week 5. Then, the rats were killed to observe and test the influence of A-SeQDs on the vascular dysfunction induced by isocarbophos. Finally, human umbilical vein endothelial cells (HUVECs) were treated with 10% DMEM of isocarbophos (100 μM) for 5 days to detect the related indexes. Before the use of isocarbophos treatment, different drugs were given. RESULTS A-SeQDs could reduce total carbon dioxide, MDA, VCAM-1, ICAM-1, IL-1, and IL-6 while increasing oxygen saturation, NO content, and SOD activity in rats. A-SeQDs also resulted in relatively normal vascular morphology, and the expression of sodium hydrogen exchanger 1 (NHE1) and caspase-3 decreased in rats. Furthermore, in HUVECs treated with isocarbophos, A-SeQDs maintained mitochondrial membrane potential, inhibited the cleaved caspase-3 expression, and released cytochrome c from mitochondria to cytosol. CONCLUSION A-SeQDs can inhibit the apoptosis of HUVECs through the mitochondrial pathway, and effectively treat the impairment of vascular endothelial function caused by isocarbophos, which is NHE1-dependent.
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Affiliation(s)
- Moli Zhu
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, China
- Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, China
| | - Zhitao Gao
- School of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
| | - Yutian Fu
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Yue Qiu
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Keke Huang
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Chaonan Zhu
- Department of Pharmacy, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Yinan Wu
- Sanquan Medical College, Xinxiang Medical University, Xinxiang, China
| | - Tiantian Zhu
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Qianqian Wang
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Lin Yang
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, China
- Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, China
| | - Yaling Yin
- Basic Medical College, Xinxiang Medical University, Xinxiang, China
| | - Peng Li
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China
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Rambabu L, Mohamed F, Dhanarisi J, Gawarammana I, Raubenheimer J, Mackenzie L, Roberts MS, Buckley N, Eddleston M. Acute phenthoate self-poisoning: a prospective case series. Clin Toxicol (Phila) 2021; 60:214-220. [PMID: 33960866 DOI: 10.1080/15563650.2021.1917596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND The clinical characteristics following self-poisoning with organophosphorus (OP) insecticides differs according to the insecticide ingested. Phenthoate is a dimethoxy WHO Hazard Class II OP pesticide with limited literature on its clinical characteristics and outcome. We aimed to better understand its clinical characteristics by studying patients with phenthoate self-poisoning in Sri Lanka. METHODS We conducted a prospective cohort study of patients presenting with phenthoate self-poisoning to eight hospitals in Sri Lanka between 2002 and 2018. Clinical outcomes were recorded for each patient. Blood samples for measuring plasma phenthoate concentration, cholinesterase activity, and response to oximes were available for a very small number of patients recruited to a clinical trial. RESULTS Two hundred and ninety-two patients who ingested agricultural phenthoate formulations were included in the study. Median time to admission was 3.9 (IQR 2.4 - 6.8) h. Forty-two (14.4%) patients were intubated, mostly (30/37, 81%) within 24 h of ingestion (median time to intubation 7.2 [IQR 2.6-20.9] h). Median duration of intubation was 74.8 (IQR 26.8-232.5) h; the longest duration in a survivor was 592 h. Nineteen died (case fatality 6.5%, 95% CI 4.0-10.0); median time to death was 37 (IQR 16 - 101.7) h. Median plasma phenthoate concentration in patients with samples (n = 81) was 135 (IQR 62.7-356.5) ng/mL (0.42 µmol/mL [0.2 to 1.1 µmol/mL]). Five of six patients receiving pralidoxime chloride 2 g showed an initial increase in AChE and BuChE activity that was not sustained despite an infusion of pralidoxime. CONCLUSION Phenthoate self-poisoning has a 6.5% case fatality rate. Most patients who experience respiratory failure undergo early intubation; most deaths occurred among those patients who were intubated less than 24 h after ingestion. There was a non-sustained increase in cholinesterase activity with pralidoxime, but further studies are required to analyse the extent to which oximes are clinically effective in phenthoate self-poisoning.
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Affiliation(s)
- Lekaashree Rambabu
- National Health Service Tayside, Dundee, UK.,Edinburgh Medical School, The University of Edinburgh, Edinburgh, UK
| | - Fahim Mohamed
- South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka.,Department of Pharmacy, Faculty of Allied Health Sciences, University of Peradeniya, Peradeniya, Sri Lanka
| | - Jeevan Dhanarisi
- South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
| | - Indika Gawarammana
- South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
| | - Jacques Raubenheimer
- Faculty of Medicine and Health, Discipline of Biomedical Informatics and Digital Health, Clinical Pharmacology and Toxicology Research Group, The University of Sydney, Sydney, Australia
| | - Lorraine Mackenzie
- Therapeutics Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, Australia.,Basil Hetzel Institute for Translational Research, The Queen Elizabeth Hospital, Woodville, Australia
| | - Michael S Roberts
- Therapeutics Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, Australia.,Therapeutics Research Centre, Diamantina Institute, Translational Research Institute, The University of Queensland, Brisbane, Australia
| | - Nicholas Buckley
- Clinical Pharmacology and Toxicology Research Group, Discipline of Pharmacology, University of Sydney, Sydney, Australia
| | - Michael Eddleston
- Pharmacology, Toxicology, & Therapeutics, University/BHF Centre for Cardiovascular Science, Edinburgh, UK.,Centre for Pesticide Suicide Prevention, University of Edinburgh, Edinburgh, UK
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10
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Toxicokinetics of temephos after oral administration to adult male rats. Arch Toxicol 2021; 95:935-947. [PMID: 33471133 DOI: 10.1007/s00204-021-02975-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/04/2021] [Indexed: 02/06/2023]
Abstract
Temephos (Tem) is the larvicide of choice to control mosquito transmission of dengue, Zika, and chikungunya. The toxicokinetic and toxicological information of temephos is very limited. The aim of this work was to determine the toxicokinetics and dosimetry of temephos and its metabolites. Male Wistar rats were orally administered temephos (300 mg/kg) emulsified with saline solution and sacrificed over time after dosing. Temephos and its metabolites were analyzed in blood and tissues by high performance liquid chromatography-diode array detector. At least eleven metabolites were detected, including temephos-sulfoxide (Tem-SO), temephos-oxon (Tem-oxon), temephos-oxon-sulfoxide (Tem-oxon-SO), temephos-oxon-SO-monohydrolyzed (Tem-oxon-SO-OH), 4,4´-thiodiphenol, 4,4´-sulfinyldiphenol, and 4,4´-sulfonyldiphenol or bisphenol S (BPS). The mean blood concentrations of temephos were fitted to a one-compartment model for kinetic analysis. At 2 h, the peak was reached (t1/2 abs = 0.38 h), and only trace levels were detected at 36 h (t1/2 elim = 8.6 h). Temephos was detected in all tissues and preferentially accumulated in fat. Temephos-sulfone-monohydrolyzed (Tem-SO2-OH) blood levels remained constant until 36 h and gradually accumulated in the kidney. Tem-oxon was detected in the brain, liver, kidney, and fat. Clearance from the liver and kidney were 7.59 and 5.52 ml/min, respectively. These results indicate that temephos is well absorbed, extensively metabolized, widely distributed and preferentially stored in adipose tissue. It is biotransformed into reactive metabolites such as Tem-oxons, Tem-dioxons, and BPS. Tem-SO2-OH, the most abundant metabolite of temephos, could be used as an exposure biomarker for toxicokinetic modeling. These results could provide critical insight into the dosimetry and toxicity of temephos and its metabolites.
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11
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Tsagkaris A, Migliorelli D, Uttl L, Filippini D, Pulkrabova J, Hajslova J. A microfluidic paper-based analytical device (μPAD) with smartphone readout for chlorpyrifos-oxon screening in human serum. Talanta 2021; 222:121535. [DOI: 10.1016/j.talanta.2020.121535] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 08/05/2020] [Accepted: 08/08/2020] [Indexed: 02/06/2023]
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12
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Turton N, Heaton RA, Ismail F, Roberts S, Nelder S, Phillips S, Hargreaves IP. The Effect of Organophosphate Exposure on Neuronal Cell Coenzyme Q 10 Status. Neurochem Res 2021; 46:131-139. [PMID: 32306167 PMCID: PMC7829235 DOI: 10.1007/s11064-020-03033-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/08/2020] [Accepted: 04/10/2020] [Indexed: 12/17/2022]
Abstract
Organophosphate (OP) compounds are widely used as pesticides and herbicides and exposure to these compounds has been associated with both chronic and acute forms of neurological dysfunction including cognitive impairment, neurophysiological problems and cerebral ataxia with evidence of mitochondrial impairment being associated with this toxicity. In view of the potential mitochondrial impairment, the present study aimed to investigate the effect of exposure to commonly used OPs, dichlorvos, methyl-parathion (parathion) and chloropyrifos (CPF) on the cellular level of the mitochondrial electron transport chain (ETC) electron carrier, coenzyme Q10 (CoQ10) in human neuroblastoma SH-SY5Y cells. The effect of a perturbation in CoQ10 status was also evaluated on mitochondrial function and cell viability. A significant decreased (P < 0.0001) in neuronal cell viability was observed following treatment with all three OPs (100 µM), with dichlorvos appearing to be the most toxic to cells and causing an 80% loss of viability. OP treatment also resulted in a significant diminution in cellular CoQ10 status, with levels of this isoprenoid being decreased by 72% (P < 0.0001), 62% (P < 0.0005) and 43% (P < 0.005) of control levels following treatment with dichlorvos, parathion and CPF (50 µM), respectively. OP exposure was also found to affect the activities of the mitochondrial enzymes, citrate synthase (CS) and mitochondrial electron transport chain (ETC) complex II+III. Dichlorvos and CPF (50 µM) treatment significantly decreased CS activity by 38% (P < 0.0001) and 35% (P < 0.0005), respectively compared to control levels in addition to causing a 54% and 57% (P < 0.0001) reduction in complex II+III activity, respectively. Interestingly, although CoQ10 supplementation (5 μM) was able to restore cellular CoQ10 status and CS activity to control levels following OP treatment, complex II+III activity was only restored to control levels in neuronal cells exposed to dichlorvos (50 µM). However, post supplementation with CoQ10, complex II+III activity significantly increased by 33% (P < 0.0005), 25% (P < 0.005) and 35% (P < 0.0001) in dichlorvos, parathion and CPF (100 µM) treated cells respectively compared to non-CoQ10 supplemented cells. In conclusion, the results of this study have indicated evidence of neuronal cell CoQ10 deficiency with associated mitochondrial dysfunction following OP exposure. Although CoQ10 supplementation was able to ameliorate OP induced deficiencies in CS activity, ETC complex II+III activity appeared partially refractory to this treatment. Accordingly, these results indicate the therapeutic potential of CoQ10 supplementation in the treatment of OP poisoning. However, higher doses may be required to engender therapeutic efficacy.
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Affiliation(s)
- Nadia Turton
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Robert A Heaton
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Fahima Ismail
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Sioned Roberts
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Sian Nelder
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Sue Phillips
- The Royal Liverpool University Hospital, Royal Liverpool and Broadgreen NHS Trust, Prescot Street, Liverpool, UK
| | - Iain P Hargreaves
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK.
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13
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Kasteel EEJ, Nijmeijer SM, Darney K, Lautz LS, Dorne JLCM, Kramer NI, Westerink RHS. Acetylcholinesterase inhibition in electric eel and human donor blood: an in vitro approach to investigate interspecies differences and human variability in toxicodynamics. Arch Toxicol 2020; 94:4055-4065. [PMID: 33037899 PMCID: PMC7655571 DOI: 10.1007/s00204-020-02927-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/05/2020] [Indexed: 02/07/2023]
Abstract
In chemical risk assessment, default uncertainty factors are used to account for interspecies and interindividual differences, and differences in toxicokinetics and toxicodynamics herein. However, these default factors come with little scientific support. Therefore, our aim was to develop an in vitro method, using acetylcholinesterase (AChE) inhibition as a proof of principle, to assess both interspecies and interindividual differences in toxicodynamics. Electric eel enzyme and human blood of 20 different donors (12 men/8 women) were exposed to eight different compounds (chlorpyrifos, chlorpyrifos-oxon, phosmet, phosmet-oxon, diazinon, diazinon-oxon, pirimicarb, rivastigmine) and inhibition of AChE was measured using the Ellman method. The organophosphate parent compounds, chlorpyrifos, phosmet and diazinon, did not show inhibition of AChE. All other compounds showed concentration-dependent inhibition of AChE, with IC50s in human blood ranging from 0.2-29 µM and IC20s ranging from 0.1-18 µM, indicating that AChE is inhibited at concentrations relevant to the in vivo human situation. The oxon analogues were more potent inhibitors of electric eel AChE compared to human AChE. The opposite was true for carbamates, pointing towards interspecies differences for AChE inhibition. Human interindividual variability was low and ranged from 5-25%, depending on the concentration. This study provides a reliable in vitro method for assessing human variability in AChE toxicodynamics. The data suggest that the default uncertainty factor of ~ 3.16 may overestimate human variability for this toxicity endpoint, implying that specific toxicodynamic-related adjustment factors can support quantitative in vitro to in vivo extrapolations that link kinetic and dynamic data to improve chemical risk assessment.
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Affiliation(s)
- Emma E J Kasteel
- Toxicology Division, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.177, 3508TD, Utrecht, The Netherlands
| | - Sandra M Nijmeijer
- Toxicology Division, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.177, 3508TD, Utrecht, The Netherlands
| | - Keyvin Darney
- Risk Assessment Department, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), 14 Rue Pierre et Marie Curie, 94701, Maisons-Alfort, France
| | - Leonie S Lautz
- Risk Assessment Department, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), 14 Rue Pierre et Marie Curie, 94701, Maisons-Alfort, France
| | - Jean Lou C M Dorne
- European Food Safety Authority, Scientific Committee and Emerging Risks Unit, Via Carlo Magno 1A, 43126, Parma, Italy
| | - Nynke I Kramer
- Toxicology Division, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.177, 3508TD, Utrecht, The Netherlands
| | - Remco H S Westerink
- Toxicology Division, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.177, 3508TD, Utrecht, The Netherlands.
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14
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Zhao S, Kamelia L, Boonpawa R, Wesseling S, Spenkelink B, Rietjens IMCM. Physiologically based kinetic modelling-facilitated reverse dosimetry to predict in vivo red blood cell acetylcholinesterase inhibition following exposure to chlorpyrifos in the Caucasian and Chinese population. Toxicol Sci 2019; 171:69-83. [PMID: 31214721 PMCID: PMC6736452 DOI: 10.1093/toxsci/kfz134] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 03/26/2019] [Accepted: 05/23/2019] [Indexed: 11/25/2022] Open
Abstract
Organophosphates have a long history of use as insecticides over the world. The aim of the present study was to investigate the interethnic differences in kinetics, biomarker formation, and in vivo red blood cell acetylcholinesterase inhibition of chlorpyrifos (CPF) in the Chinese and the Caucasian population. To this purpose, physiologically based kinetic models for CPF in both the Chinese and Caucasian population were developed, and used to study time- and dose-dependent interethnic variation in urinary biomarkers and to convert concentration-response curves for red blood cell acetylcholinesterase inhibition to in vivo dose-response curves in these 2 populations by reverse dosimetry. The results obtained revealed a marked interethnic difference in toxicokinetics of CPF, with lower urinary biomarker levels at similar dose levels and slower CPF bioactivation and faster chlorpyrifos-oxon detoxification in the Chinese compared with the Caucasian population, resulting in 5- to 6-fold higher CPF sensitivity of the Caucasian than the Chinese population. These differences might be related to variation in the frequency of single-nucleotide polymorphisms for the major biotransformation enzymes involved. To conclude, the interethnic variation in kinetics of CPF may affect both its biomarker-based exposure assessment and its toxicity and risk assessment and physiologically based kinetic modeling facilitates the characterization and quantification of these interethnic variations.
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Affiliation(s)
- Shensheng Zhao
- Division of Toxicology, Wageningen University and Research, Wageningen, The Netherlands
| | - Lenny Kamelia
- Division of Toxicology, Wageningen University and Research, Wageningen, The Netherlands
| | - Rungnapa Boonpawa
- Faculty of Natural Resources and Agro-Industry, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Thailand
| | - Sebastiaan Wesseling
- Division of Toxicology, Wageningen University and Research, Wageningen, The Netherlands
| | - Bert Spenkelink
- Division of Toxicology, Wageningen University and Research, Wageningen, The Netherlands
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University and Research, Wageningen, The Netherlands
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15
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Schopfer LM, Lockridge O. Chlorpyrifos oxon promotes tubulin aggregation via isopeptide cross-linking between diethoxyphospho-Lys and Glu or Asp: Implications for neurotoxicity. J Biol Chem 2018; 293:13566-13577. [PMID: 30006344 PMCID: PMC6120212 DOI: 10.1074/jbc.ra118.004172] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/09/2018] [Indexed: 11/06/2022] Open
Abstract
Exposure to organophosphorus toxicants (OP) can have chronic adverse effects that are not explained by inhibition of acetylcholinesterase, the cause of acute OP toxicity. We therefore hypothesized that OP-induced chronic illness is initiated by the formation of organophosphorus adducts on lysine residues in proteins, followed by protein cross-linking and aggregation. Here, Western blots revealed that exposure to the OP chlorpyrifos oxon converted porcine tubulin from its original 55-kDa mass to high-molecular-weight aggregates. Liquid chromatography–tandem MS analysis of trypsin-digested samples identified several diethoxyphospho-lysine residues in the OP-treated tubulin. Using a search approach based on the Batch Tag program, we identified cross-linked peptides and found that these chemically activated lysines reacted with acidic amino acid residues creating γ-glutamyl-ϵ-lysine or aspartyl-ϵ-lysine isopeptide bonds between β- and α-tubulin. Of note, these cross-linked tubulin molecules accounted for the high-molecular-weight aggregates. To the best of our knowledge, this is the first report indicating that chlorpyrifos oxon–exposed tubulin protein forms intermolecular cross-links with other tubulin molecules, resulting in high-molecular-weight protein aggregates. It is tempting to speculate that chronic illness from OP exposure may be explained by a mechanism that starts with OP adduct formation on protein lysines followed by protein cross-linking. We further speculate that OP-modified or cross-linked tubulin can impair axonal transport, reduce neuron connections, and result in neurotoxicity.
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Affiliation(s)
- Lawrence M Schopfer
- From the Eppley Institute, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900
| | - Oksana Lockridge
- From the Eppley Institute, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900
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16
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Onder S, Schopfer LM, Tacal O, Blake TA, Johnson RC, Lockridge O. Mass Spectral Detection of Diethoxyphospho-Tyrosine Adducts on Proteins from HEK293 Cells Using Monoclonal Antibody depY for Enrichment. Chem Res Toxicol 2018; 31:520-530. [PMID: 29775289 PMCID: PMC6008731 DOI: 10.1021/acs.chemrestox.8b00083] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Chronic illness from exposure to
organophosphorus toxicants is
hypothesized to involve modification of unknown proteins. Tyrosine
in proteins that have no active site serine readily reacts with organophosphorus
toxicants. We developed a monoclonal antibody, depY, that specifically
recognizes diethoxyphospho-tyrosine in proteins and peptides, independent
of the surrounding amino acid sequence. Our goal in the current study
was to identify diethoxyphosphorylated proteins in human HEK293 cell
lysate treated with chlorpyrifos oxon. Cell lysates treated with chlorpyrifos
oxon were recognized by depY antibody in ELISA and capillary electrophoresis
based Western blot. Tryptic peptides were analyzed by liquid chromatography
tandem mass spectrometry. Liquid chromatography tandem mass spectrometry
identified 116 diethoxyphospho-tyrosine peptides from 73 proteins
in immunopurified samples, but found only 15 diethoxyphospho-tyrosine
peptides from 12 proteins when the same sample was not immunopurified
on depY. The most abundant proteins in the cell lysate, histone H4,
heat shock 70 kDa protein 1A/1B, heat shock protein HSP 90 β,
and α-enolase, were represented by several diethoxyphospho-tyrosine
peptides. It was concluded that use of immobilized depY improved the
number of diethoxyphospho-tyrosine peptides identified in a complex
mixture. The mass spectrometry results confirmed the specificity of
depY for diethoxyphospho-tyrosine peptides independent of the context
of the modified tyrosine, which means depY could be used to analyze
modified proteins in any species. Use of the depY antibody could lead
to an understanding of chronic illness from organophosphorus pesticide
exposure.
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Affiliation(s)
- Seda Onder
- Department of Biochemistry, School of Pharmacy , Hacettepe University , Ankara 06100 , Turkey.,Eppley Institute , University of Nebraska Medical Center , Omaha , Nebraska 68198 , United States
| | - Lawrence M Schopfer
- Eppley Institute , University of Nebraska Medical Center , Omaha , Nebraska 68198 , United States
| | - Ozden Tacal
- Department of Biochemistry, School of Pharmacy , Hacettepe University , Ankara 06100 , Turkey
| | - Thomas A Blake
- Division of Laboratory Sciences, National Center for Environmental Health , Centers for Disease Control and Prevention , 4770 Buford Highway NE , Atlanta , Georgia 30341 , United States
| | - Rudolph C Johnson
- Division of Laboratory Sciences, National Center for Environmental Health , Centers for Disease Control and Prevention , 4770 Buford Highway NE , Atlanta , Georgia 30341 , United States
| | - Oksana Lockridge
- Eppley Institute , University of Nebraska Medical Center , Omaha , Nebraska 68198 , United States
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17
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Yang X, Wu X, Brown KA, Le T, Stice SL, Bartlett MG. Determination of chlorpyrifos and its metabolites in cells and culture media by liquid chromatography-electrospray ionization tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1063:112-117. [PMID: 28858752 DOI: 10.1016/j.jchromb.2017.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 07/17/2017] [Accepted: 08/07/2017] [Indexed: 01/01/2023]
Abstract
A sensitive method to simultaneously quantitate chlorpyrifos, chlorpyrifos oxon and the detoxified product 3,5,6-trichloro-2-pyridinol (TCP) was developed using either liquid-liquid extraction for culture media samples, or protein precipitation for cell samples. Multiple reaction monitoring in positive ion mode was applied for the detection of chlorpyrifos and chlorpyrifos oxon, and selected ion recording in negative mode was applied to detect TCP. The method provided linear ranges from 5 to 500, 0.2-20 and 20-2000ng/mL for media samples and from 0.5-50, 0.02-2 and 2-200ng/million cells for CPF, CPO and TCP, respectively. The method was validated using selectivity, linearity, precision, accuracy, recovery, stability and dilution tests. All relative standard deviations (RSDs) and relative errors (REs) for QC samples were within 15% (except for LLOQ, within 20%). This method has been successfully applied to study the neurotoxicity and metabolism of chlorpyrifos in a human neuronal model.
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Affiliation(s)
- Xiangkun Yang
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, GA 30602-2352, United States
| | - Xian Wu
- Regenerative Bioscience Center, University of Georgia, Athens, GA 30602, United States
| | - Kyle A Brown
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, GA 30602-2352, United States
| | - Thao Le
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, GA 30602-2352, United States
| | - Steven L Stice
- Regenerative Bioscience Center, University of Georgia, Athens, GA 30602, United States
| | - Michael G Bartlett
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, The University of Georgia, Athens, GA 30602-2352, United States.
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18
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Wu X, Yang X, Majumder A, Swetenburg R, Goodfellow FT, Bartlett MG, Stice SL. From the Cover: AstrocytesAre Protective Against Chlorpyrifos Developmental Neurotoxicity in Human Pluripotent Stem Cell-Derived Astrocyte-Neuron Cocultures. Toxicol Sci 2017; 157:410-420. [DOI: 10.1093/toxsci/kfx056] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- Xian Wu
- Department of Animal and Dairy Science, Interdisciplinary Toxicology Program
- Department of Animal and Dairy Science, Regenerative Bioscience Center
| | - Xiangkun Yang
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602
| | | | | | - Forrest T. Goodfellow
- Department of Animal and Dairy Science, Interdisciplinary Toxicology Program
- Department of Animal and Dairy Science, Regenerative Bioscience Center
| | - Michael G. Bartlett
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602
| | - Steven L. Stice
- Department of Animal and Dairy Science, Interdisciplinary Toxicology Program
- Department of Animal and Dairy Science, Regenerative Bioscience Center
- ArunA Biomedical, Athens, Georgia 30602
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19
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Chlorpyrifos poisoning and its implications in human fatal cases: A forensic perspective with reference to Indian scenario. J Forensic Leg Med 2017; 47:29-34. [PMID: 28259020 DOI: 10.1016/j.jflm.2017.02.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 10/13/2016] [Accepted: 02/16/2017] [Indexed: 11/23/2022]
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20
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Howell III GE, Mulligan C, Young D, Kondakala S. Exposure to chlorpyrifos increases neutral lipid accumulation with accompanying increased de novo lipogenesis and decreased triglyceride secretion in McArdle-RH7777 hepatoma cells. Toxicol In Vitro 2016; 32:181-9. [DOI: 10.1016/j.tiv.2016.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 12/09/2015] [Accepted: 01/06/2016] [Indexed: 01/14/2023]
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21
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Lu C, Liu X, Liu C, Wang J, Li C, Liu Q, Li Y, Li S, Sun S, Yan J, Shao J. Chlorpyrifos Induces MLL Translocations Through Caspase 3-Dependent Genomic Instability and Topoisomerase II Inhibition in Human Fetal Liver Hematopoietic Stem Cells. Toxicol Sci 2015. [PMID: 26198043 DOI: 10.1093/toxsci/kfv153] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Household pesticide exposure during pregnancy has been associated with a more than 2-fold increased risk in infant leukemia, and chlorpyrifos (CPF) is among the most frequently applied insecticides. During early fetal development, liver is a hematopoietic organ with majority of cells being CD34(+) hematopoietic stem cells (CD34(+)HSC). The in utero injury to CD34(+)HSC has been known to underlie the pathogenesis of several blood disorders, often involving rearrangements of the mixed-lineage leukemia (MLL) gene on 11q23. In this study, we evaluated the leukemogenic potential of CPF in human fetal liver-derived CD34(+)HSC. Specifically, exposure to 10 μM CPF led to decrease in viability, inhibition in proliferation and induction of DNA double-strand breaks (DSBs) and occurrence of MLL(+) rearrangements. In particular, we observed CPF-mediated cell cycle disturbance as shown by G0/G1 arrest, in contrast to etoposide (VP-16), an anticancer drug used as a positive control and known to induce G2/M arrest. Further study on mechanisms underlying DNA DSBs and MLL(+) rearrangements revealed that CPF might act as topoisomerase II poison, a mechanism of action similar to VP-16. On the other hand, CPF was also shown to induce early apoptosis through active caspase-3 activation, a pathway known to underlie DNA DSBs and MLL(+) translocations. Our data indicate that in utero injury of CD34(+)HSC by CPF may contribute to the increased risk of infant leukemia. Future work will elucidate the mechanism and the type of CPF-induced MLL(+) translocations in HSC.
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Affiliation(s)
- Chengquan Lu
- *Dalian Key Laboratory of Hematology, Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University. Dalian, Liaoning, China 116044
| | - Xiaohui Liu
- *Dalian Key Laboratory of Hematology, Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University. Dalian, Liaoning, China 116044
| | - Chang Liu
- *Dalian Key Laboratory of Hematology, Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University. Dalian, Liaoning, China 116044
| | - Jian Wang
- *Dalian Key Laboratory of Hematology, Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University. Dalian, Liaoning, China 116044
| | - Chunna Li
- *Dalian Key Laboratory of Hematology, Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University. Dalian, Liaoning, China 116044
| | - Qi Liu
- *Dalian Key Laboratory of Hematology, Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University. Dalian, Liaoning, China 116044
| | - Yachen Li
- *Dalian Key Laboratory of Hematology, Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University. Dalian, Liaoning, China 116044
| | - Shuangyue Li
- *Dalian Key Laboratory of Hematology, Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University. Dalian, Liaoning, China 116044
| | - Shu Sun
- Department of Obstetrics, Maternal and Child Care Service Center of Dalian, Dalian, Liaoning 116033, China
| | - Jinsong Yan
- Dalian Key Laboratory of Hematology, Department of Hematology of the Second Hospital of Dalian Medical University, Institute of Stem Cell Transplantation of Dalian Medical University, Dalian, Liaoning 116027, China
| | - Jing Shao
- *Dalian Key Laboratory of Hematology, Department of Environmental Health and Toxicology, School of Public Health, Dalian Medical University. Dalian, Liaoning, China 116044;
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Flaskos J. The Neuronal Cytoskeleton as a Potential Target in the Developmental Neurotoxicity of Organophosphorothionate Insecticides. Basic Clin Pharmacol Toxicol 2014; 115:201-8. [DOI: 10.1111/bcpt.12204] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/14/2014] [Indexed: 12/26/2022]
Affiliation(s)
- John Flaskos
- School of Veterinary Medicine; Aristotle University of Thessaloniki; Thessaloniki Greece
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Khokhar JY, Tyndale RF. Intracerebroventricularly and Systemically Delivered Inhibitor of Brain CYP2B (C8-Xanthate), Even Following Chlorpyrifos Exposure, Reduces Chlorpyrifos Activation and Toxicity in Male Rats. Toxicol Sci 2014; 140:49-60. [DOI: 10.1093/toxsci/kfu075] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Pelit FO, Yengin Ç. Application of solidified floating organic drop microextraction method for biomonitoring of chlorpyrifos and its oxon metabolite in urine samples. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 949-950:109-14. [DOI: 10.1016/j.jchromb.2014.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 12/25/2013] [Accepted: 01/04/2014] [Indexed: 10/25/2022]
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Hrabetz H, Thiermann H, Felgenhauer N, Zilker T, Haller B, Nährig J, Saugel B, Eyer F. Organophosphate poisoning in the developed world - a single centre experience from here to the millennium. Chem Biol Interact 2013; 206:561-8. [PMID: 23685200 DOI: 10.1016/j.cbi.2013.05.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 05/06/2013] [Accepted: 05/08/2013] [Indexed: 12/20/2022]
Abstract
Organophosphate (OP) poisoning is still associated with high morbidity and mortality rates, both in resource-poor settings and in well-developed countries. Despite numerous publications dealing with this particular poison, detailed clinical data on more severe overdoses with these agents are relatively sparsely reported. A retrospective study was consequently conducted on 33 patients with OP poisoning admitted to our intensive care unit (ICU) to provide additional data on clinical features. We included moderate to severe poisonings between 2000 and 2012 who required admission to ICU. Patients ingested dimethyl-OPs in 19 cases, diethyl-OPs in 8 cases and otherwise classified OPs in 6 cases. Death (5/33) occurred rather late and only one of these fatalities died during on-going cholinergic crisis. Of the survivors (28/33), 71% recovered fully while 29% showed predominantly neurological disabilities before being transferred to neurologic rehabilitation. Aspiration pneumonia predominated in 27/33 patients and one patient died in refractory acute respiratory distress syndrome (ARDS). The intermediate syndrome occurred twice and cardiopulmonary resuscitation had to be performed in 6/33 patients. Fatalities showed a higher Poison-severity-score, APACHE-II-score and SOFA-score on admission compared with survivors and they showed significantly longer QTc-time in the ECG, lower systolic blood pressure and heart rate, a lower pH and a lower base excess on admission. Patients with diethyl-OPs required intubation significantly earlier and showed lower and more sustained inhibited activity of the plasma-cholinesterase on admission compared with patients ingesting dimethyl-OPs. Treatment with atropine and obidoxime was comparable between these groups and severity of poisoning, outcome, hemodynamics on admission, duration of mechanical ventilation and length of stay in the ICU did not significantly differ between the involved group of dimethyl- and diethyl-OPs. We conclude that the fatality rate in our patient cohort treated in a well-staffed and equipped ICU of a developed country is quite similarly high compared with the rate observed in developing countries. Patients died rather late when severe cholinergic crisis had mostly been overcome and death was therefore related to non-poison specific complications.
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Affiliation(s)
- Heidi Hrabetz
- Department of Clinical Toxicology, II. Medizinische Klinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany
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26
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Chaou CH, Lin CC, Chen HY, Lee CH, Chen THH. Chlorpyrifos is associated with slower serum cholinesterase recovery in acute organophosphate-poisoned patients. Clin Toxicol (Phila) 2013; 51:402-8. [PMID: 23590812 DOI: 10.3109/15563650.2013.782035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE Organophosphate poisoning (OPP) accounts for 200,000 deaths annually in developing countries. Serum cholinesterase (SChE) is of diagnostic value in patients with OPP and is checked repeatedly during the course of treatment. This study aimed to investigate the recovery pattern in patients with OPP using linear mixed models. METHODS Using a retrospective cohort study design, we included 212 adult OPP patients who had visited the emergency department (ED) in a tertiary medical center between 2000 and 2010. One hundred and thirty-one patients were available for analysis, as 81 patients did not meet the criteria and were excluded. Information regarding basic personal characteristics, initial vital signs and severity scores, laboratory data, type and amount of organophosphate ingested, treatment, and serial SChE values was collected. A random coefficient model with a random intercept and a random slope of time were added to address the dynamic relationships of SChE with time and other associated factors. RESULTS The initial SChE activity and recovery rates varied among patients with OPP. The type of organophosphate, the first SChE activity, and the initial APACHE II score were significantly related to the SChE recovery trend. Chlorpyrifos and methamidophos had significantly slower and faster SChE recovery rates, respectively, than other organophosphates. Sex, dose of Pralidoxim (2-PAM), and delay in obtaining medical assistance did not significantly affect SChE recovery. CONCLUSIONS This study demonstrated the pattern and associated correlates of SChE activity recovery in patients with acute OPP. Chlorpyrifos appeared to have a slower SChE activity recovery rate than other organophosphates.
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Affiliation(s)
- C H Chaou
- Department of Emergency Medicine, Chang Gung Memorial Hospital and Chang Gung University College of Medicine , Taoyuan , Taiwan
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Li B, Eyer P, Eddleston M, Jiang W, Schopfer LM, Lockridge O. Protein tyrosine adduct in humans self-poisoned by chlorpyrifos. Toxicol Appl Pharmacol 2013; 269:215-25. [PMID: 23566956 DOI: 10.1016/j.taap.2013.03.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/26/2013] [Accepted: 03/27/2013] [Indexed: 10/27/2022]
Abstract
Studies of human cases of self-inflicted poisoning suggest that chlorpyrifos oxon reacts not only with acetylcholinesterase and butyrylcholinesterase but also with other blood proteins. A favored candidate is albumin because in vitro and animal studies have identified tyrosine 411 of albumin as a site covalently modified by organophosphorus poisons. Our goal was to test this proposal in humans by determining whether plasma from humans poisoned by chlorpyrifos has adducts on tyrosine. Plasma samples from 5 self-poisoned humans were drawn at various time intervals after ingestion of chlorpyrifos for a total of 34 samples. All 34 samples were analyzed for plasma levels of chlorpyrifos and chlorpyrifos oxon (CPO) as a function of time post-ingestion. Eleven samples were analyzed for the presence of diethoxyphosphorylated tyrosine by mass spectrometry. Six samples yielded diethoxyphosphorylated tyrosine in pronase digests. Blood collected as late as 5days after chlorpyrifos ingestion was positive for CPO-tyrosine, consistent with the 20-day half-life of albumin. High plasma CPO levels did not predict detectable levels of CPO-tyrosine. CPO-tyrosine was identified in pralidoxime treated patients as well as in patients not treated with pralidoxime, indicating that pralidoxime does not reverse CPO binding to tyrosine in humans. Plasma butyrylcholinesterase was a more sensitive biomarker of exposure than adducts on tyrosine. In conclusion, chlorpyrifos oxon makes a stable covalent adduct on the tyrosine residue of blood proteins in humans who ingested chlorpyrifos.
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Affiliation(s)
- Bin Li
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE 68198-5950 USA.
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New tools in diagnosis and biomonitoring of intoxications with organophosphorothioates: case studies with chlorpyrifos and diazinon. Chem Biol Interact 2012; 203:96-102. [PMID: 23123253 DOI: 10.1016/j.cbi.2012.10.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/03/2012] [Accepted: 10/09/2012] [Indexed: 11/20/2022]
Abstract
Organophosphate (OP) pesticides are neurotoxic compounds that are widely used in agriculture. Classical methods for monitoring OP exposure comprise the measurement of intact OP, its metabolites or cholinesterase activity. Newly developed methods focus on the analysis of the OP adduct bound to proteins such as butyrylcholinesterase (BuChE) and albumin. These adducts can be analyzed by means of fluoride reactivation or by analysis with LC-MS/MS of the pepsin or pronase digest of butyrylcholinesterase and albumin, respectively. The utility of these methods is illustrated through the analysis of plasma samples obtained from patients taken 1-49 days after ingestion of the organophosphate pesticides chlorpyrifos and/or diazinon. Thus, in this particular case several independent methodologies were applied to the biomedical samples, all pointing to the same exposure.
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29
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Pelit FO, Pelit L, Ertaş H, Nil Ertaş F. Development of a gas chromatographic method for the determination of Chlorpyrifos and its metabolite Chlorpyrifos-oxon in wine matrix. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 904:35-41. [DOI: 10.1016/j.jchromb.2012.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 07/09/2012] [Accepted: 07/11/2012] [Indexed: 11/29/2022]
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Abstract
Chlorpyrifos (CPF), an organophosphorus (OP) pesticide, is bioactivated by cytochrome P450s (CYPs) to the active metabolite chlorpyrifos oxon (CPF-O). Given that human CYP2B6 has the highest intrinsic clearance (CL(int)) for CPF bioactivation, CYP2B6 polymorphisms may impact human susceptibility to CPF at real world environmental and occupational CPF exposure levels. CYP2B6.4,.5,.7, and .18 were over-expressed in mammalian COS-1 cells to assess the impact of CYP2B6 variants on the K(m) and V(max) for bioactivation of CPF. Cell lysates were incubated with CPF (0-100 μM) and the production of CPF-O was measured via HPLC analysis. CYP2B6 content was determined by western blot. CYP2B6.18 had neither detectable protein nor activity levels. The V(max) value for each remaining variant was significantly higher than wild-type (CYP2B6.1, V(max) 4.13 × 10(4) pmol/min/nmol CYP2B6), with CYP2B6.4,.5, and .7 having V(max) values of 4.52 × 10(5), 1.82 × 10(5), and 9.60 × 10(4) pmol/min/nmol CYP2B6, respectively. The K(m) values for these variants ranged from 0.39 to 1.09 μM and were not significantly different from wild-type. All active variants examined had significantly higher CL(int) than CYP2B6.1. Variants of CYP2B6 have altered capacity to bioactivate CPF and may affect individual susceptibility by altering the V(max) for CPF-O formation.
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Affiliation(s)
- Alice L Crane
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, NY, USA
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31
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Flaskos J. The developmental neurotoxicity of organophosphorus insecticides: A direct role for the oxon metabolites. Toxicol Lett 2012; 209:86-93. [DOI: 10.1016/j.toxlet.2011.11.026] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 11/25/2011] [Accepted: 11/26/2011] [Indexed: 01/14/2023]
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Effects of sub-lethal neurite outgrowth inhibitory concentrations of chlorpyrifos oxon on cytoskeletal proteins and acetylcholinesterase in differentiating N2a cells. Toxicol Appl Pharmacol 2011; 256:330-6. [DOI: 10.1016/j.taap.2011.06.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 06/01/2011] [Accepted: 06/03/2011] [Indexed: 11/18/2022]
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33
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John H, Blum MM. Review of UV spectroscopic, chromatographic, and electrophoretic methods for the cholinesterase reactivating antidote pralidoxime (2-PAM). Drug Test Anal 2011; 4:179-93. [DOI: 10.1002/dta.327] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 06/21/2011] [Accepted: 06/21/2011] [Indexed: 11/06/2022]
Affiliation(s)
- Harald John
- Bundeswehr Institute of Pharmacology and Toxicology; Munich; Germany
| | - Marc-Michael Blum
- Los Alamos National Laboratory, Bioscience Division; Los Alamos; NM; USA (LA-UR 11-04236)
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In vitro kinetic interactions of DEET, pyridostigmine and organophosphorus pesticides with human cholinesterases. Chem Biol Interact 2011; 190:79-83. [PMID: 21354413 DOI: 10.1016/j.cbi.2011.02.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 02/17/2011] [Accepted: 02/18/2011] [Indexed: 11/20/2022]
Abstract
The simultaneous use of the repellent DEET, pyridostigmine, and organophosphorus pesticides has been assumed as a potential cause for the Gulf War Illness and combinations have been tested in different animal models. However, human in vitro data on interactions of DEET with other compounds are scarce and provoked the present in vitro study scrutinizing the interactions of DEET, pyridostigmine and pesticides with human acetylcholinesterase (hAChE) and butyrylcholinesterase (hBChE). DEET showed to be a weak and reversible inhibitor of hAChE and hBChE. The IC(50) of DEET was calculated to be 21.7mM DEET for hAChE and 3.2mM DEET for hBChE. The determination of the inhibition kinetics of pyridostigmine, malaoxon and chlorpyrifos oxon with hAChE in the presence of 5mM DEET resulted in a moderate reduction of the inhibition rate constant k(i). The decarbamoylation velocity of pyridostigmine-inhibited hAChE was not affected by DEET. In conclusion, the in vitro investigation of interactions between human cholinesterases, DEET, pyridostigmine, malaoxon and chlorpyrifos oxon showed a weak inhibition of hAChE and hBChE by DEET. The inhibitory potency of the tested cholinesterase inhibitors was not enhanced by DEET and it did not affect the regeneration velocity of pyridostigmine-inhibited AChE. Hence, this in vitro study does not give any evidence of a synergistic effect of the tested compounds on human cholinesterases.
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Abstract
BACKGROUND Acute organophosphorus pesticide poisoning causes tens of thousands of deaths each year across the developing world. Standard treatment involves administration of intravenous atropine and oxime to reactivate inhibited acetylcholinesterase. The clinical usefulness of oximes, such as pralidoxime and obidoxime, has been challenged over the past 20 years by physicians in many parts of the world. OBJECTIVES To quantify the effectiveness and safety of the administration of oximes in acute organophosphorus pesticide-poisoned patients. SEARCH STRATEGY We searched both English and Chinese databases: Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials (The Cochrane Library), MEDLINE (Ovid SP), EMBASE (Ovid SP), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Conference Proceedings Citation Index-Science (CPCI-S) and the Chinese language databases CNKI and WANGFANG. All searches were run in September 2009. SELECTION CRITERIA Articles that could possibly be RCTs were retrieved to determine if they were randomised. DATA COLLECTION AND ANALYSIS The published methodology of three RCTs was not clear. We contacted the principal authors of these, but did not obtain further information. MAIN RESULTS Seven pralidoxime RCTs were found. Three RCTs including 366 patients studied pralidoxime vs placebo and four RCTs including 479 patients compared two or more different doses. These trials found quite disparate results with treatment effects ranging from benefit to harm. However, many studies did not take into account several issues important for outcomes. In particular, baseline characteristics were not balanced, oxime doses varied widely, there were substantial delays to treatment, and the type of organophosphate was not taken into account. Only one RCT compared the World Health Organization (WHO) recommended doses with placebo. This trial showed no clinical benefits and a trend towards harm in all sub-groups, despite clear evidence that these doses reactivated acetylcholinesterase in the blood. AUTHORS' CONCLUSIONS Current evidence is insufficient to indicate whether oximes are harmful or beneficial. The WHO recommended regimen (30 mg/kg pralidoxime chloride bolus followed by 8 mg/kg/hr infusion) is not supported. Further RCTs are required to examine other strategies and regimens. There are many theoretical and practical reasons why oximes may not be useful, particularly for late presentations of dimethyl OP and those with a large excess of OP that simply re-inhibits reactivated enzymes. Future studies should screen for patient sub-groups that may benefit and may need flexible dosing strategies as clinical effectiveness and doses may depend on the type of OP.
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Affiliation(s)
- Nick A Buckley
- Professorial Medicine Unit, POWH Clinical School, University of NSW, South Wing, Edmund Blackett building, Prince of Wales Hospital, Randwick, NSW, Australia, 2031
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Human variation in CYP-specific chlorpyrifos metabolism. Toxicology 2010; 276:184-91. [DOI: 10.1016/j.tox.2010.08.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 08/04/2010] [Accepted: 08/05/2010] [Indexed: 11/21/2022]
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Li B, Ricordel I, Schopfer LM, Baud F, Mégarbane B, Nachon F, Masson P, Lockridge O. Detection of adduct on tyrosine 411 of albumin in humans poisoned by dichlorvos. Toxicol Sci 2010; 116:23-31. [PMID: 20395308 DOI: 10.1093/toxsci/kfq117] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Studies in mice and guinea pigs have shown that albumin is a new biomarker of organophosphorus toxicant (OP) and nerve agent exposure. Our goal was to determine whether OP-labeled albumin could be detected in the blood of humans exposed to OP. Blood from four OP-exposed patients was prepared for mass spectrometry analysis by digesting 0.010 ml of serum with pepsin and purifying the labeled albumin peptide by offline high performance liquid chromatography. Dimethoxyphosphate-labeled tyrosine 411 was identified in albumin peptides VRY(411)TKKVPQVSTPTL and LVRY(411)TKKVPQVSTPTL from two patients who had attempted suicide with dichlorvos. The butyrylcholinesterase activity in these serum samples was inhibited 80%. A third patient whose serum BChE activity was inhibited 8% by accidental inhalation of dichlorvos had undetectable levels of adduct on albumin. A fourth patient whose BChE activity was inhibited 60% by exposure to chlorpyrifos had no detectable adduct on albumin. This is the first report to demonstrate the presence of OP-labeled albumin in human patients. It is concluded that tyrosine 411 of human albumin is covalently modified in the serum of humans poisoned by dichlorvos and that the modification is detectable by mass spectrometry. The special reactivity of tyrosine 411 with OP suggests that other proteins may also be modified on tyrosine. Identification of other OP-modified proteins may lead to an understanding of neurotoxic symptoms that appear long after the initial OP exposure.
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Affiliation(s)
- Bin Li
- Eppley Institute, University of Nebraska Medical Center, Omaha, Nebraska 68198-5950, USA
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Zhang Y, Liu CZ, Li XJ, Wang ZL, Zhang HT, Miao ZG. Structures and energies of the radicals and anions generated from chlorpyrifos. J Mol Model 2010; 16:1369-76. [PMID: 20146076 DOI: 10.1007/s00894-010-0648-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 12/19/2009] [Indexed: 11/27/2022]
Abstract
The radicals and anions generated from chlorpyrifos by removing a hydrogen atom have been investigated using the hybrid density functional B3PW91 method. The results show that all the radicals have been classified as three groups and their stability order is methylene (radical 1, 3, 5, and 7) > methyl (radical 9, 11 and 13) > ring (15); the anions have the relative energetic order: methyl > methylene > ring. Moreover, some decomposition reactions are also reported. The large HOMO-LUMO gaps indicate that both radicals and anions are predicted to be high-kinetic stable molecules. We also find that radicals 9, 11 and 13 have the highest AEAs and anions 2, 4 and 6 have higher VDEs. Additionally, natural population analysis charges show that there is the lowest Deltaq (0.14) for the C7 and C9 atoms. We hope that our theoretical results may provide a reference for further experiment and practical application.
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Affiliation(s)
- Yi Zhang
- Department of Animal Science, Southwest University, Rongchang, Chongqing, People's Republic of China
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Paradox findings may challenge orthodox reasoning in acute organophosphate poisoning. Chem Biol Interact 2009; 187:270-8. [PMID: 19883634 DOI: 10.1016/j.cbi.2009.10.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 10/17/2009] [Accepted: 10/20/2009] [Indexed: 12/15/2022]
Abstract
It is generally accepted that inhibition of acetylcholinesterase (AChE) is the most important acute toxic action of organophosphorus compounds, leading to accumulation of acetylcholine followed by a dysfunction of cholinergic signaling. However, the degree of AChE inhibition is not uniformly correlated with cholinergic dysfunction, probably because the excess of essential AChE varies among tissues. Moreover, the cholinergic system shows remarkable plasticity, allowing modulations to compensate for dysfunctions of the canonical pathway. A prominent example is the living (-/-) AChE knockout mouse. Clinical experience indicates that precipitous inhibition of AChE leads to more severe poisoning than more protracted yet finally complete inhibition. The former situation is seen in parathion, the latter in oxydemeton methyl poisoning. At first glance, this dichotomy is surprising since parathion is a pro-poison and has to be activated to the oxon, while the latter is still the ultimate inhibitor. Also oxime therapy in organophosphorus poisoning apparently gives perplexing results: Oximes are usually able to reactivate diethylphosphorylated AChE, but the efficiency may be occasionally markedly smaller than expected from kinetic data. Dimethylphosphorylated AChE is in general less amenable to oxime therapy, which largely fails in some cases of dimethoate poisoning where aging was much faster than expected from a dimethylphosphorylated enzyme. Similarly, poisoning by profenofos, an O,S-dialkyl phosphate, leads to a rapidly aged enzyme. Most surprisingly, these patients were usually well on admission, yet their erythrocyte AChE was completely inhibited. Analysis of the kinetic constants of the most important reaction pathways, determination of the reactant concentrations in vivo and comparison with computer simulations may reveal unexpected toxic reactions. Pertinent examples will be presented and the potentially underlying phenomena discussed.
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40
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Eyer F, Worek F, Eyer P, Felgenhauer N, Haberkorn M, Zilker T, Thiermann H. Obidoxime in acute organophosphate poisoning: 1 - clinical effectiveness. Clin Toxicol (Phila) 2009; 47:798-806. [PMID: 19778163 DOI: 10.1080/15563650903206828] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE The effects of obidoxime in the treatment of organophosphate poisoning were assessed by comparing the clinical course with its effects on laboratory parameters relevant to poisoning. In this article we report clinical findings and activity of cholinesterase in plasma and acetylcholinesterase (AChE) in red blood cells. In a linked paper we describe changes in neuromuscular transmission and atropine concentrations in the same patient cohort. METHODS We studied 34 atropinized patients with severe parathion, oxydemeton methyl, and dimethoate self-poisoning who were treated with obidoxime in a standard protocol. We measured the AChE activity in blood and related it to clinical features of organophosphate poisoning. RESULTS Patients poisoned with parathion responded promptly to obidoxime (250 mg bolus followed by continuous infusion at 750 mg/day up to 1 week) with improvement of neuromuscular transmission and increased AChE activity. The effects were only transient in cases with the other poisons. Death (7/34) occurred late and was mostly due to complications rather than due to ongoing cholinergic crisis. CONCLUSIONS Obidoxime appeared safe and reactivated AChE in parathion poisoning.
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Affiliation(s)
- Florian Eyer
- Toxicological Department, Second Medical Clinic, Technische Universität, Munich, Germany.
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