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Harkins J, Langston J, Keith ZM, Munoz C, Acon-Chen C, Shih TM. Learning and memory function preserved by delayed A 1 adenosine receptor agonist treatment following soman intoxication in rats and a humanized esterase mouse model. Neuropharmacology 2024; 253:109983. [PMID: 38704023 PMCID: PMC11132435 DOI: 10.1016/j.neuropharm.2024.109983] [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: 01/09/2024] [Revised: 04/23/2024] [Accepted: 05/01/2024] [Indexed: 05/06/2024]
Abstract
Exposure to organophosphorus compounds, such as soman (GD), cause widespread toxic effects, sustained status epilepticus, neuropathology, and death. The A1 adenosine receptor agonist N-bicyclo-(2.2.1)-hept-2-yl-5'-chloro-5'-deoxyadenosine (ENBA), when given 1 min after GD exposure, provides neuroprotection and prevents behavioral impairments. Here, we tested the ability of ENBA at delayed treatment times to improve behavioral outcomes via a two-way active avoidance task in two male animal models, each consisting of saline and GD exposure groups. In a rat model, animals received medical treatments (atropine sulfate [A], 2-PAM [P], and midazolam [MDZ]) or AP + MDZ + ENBA at 15 or 30 min after seizure onset and were subjected to behavioral testing for up to 14 days. In a human acetylcholinesterase knock-in serum carboxylesterase knock-out mouse model, animals received AP, AP + MDZ, AP + ENBA, or AP + MDZ + ENBA at 15 min post seizure onset and were subjected to the behavioral task on days 7 and 14. In rats, the GD/AP + MDZ + ENBA group recovered to saline-exposed avoidance levels while the GD/AP + MDZ group did not. In mice, in comparison with GD/AP + MDZ group, the GD/AP + MDZ + ENBA showed decreases in escape latency, response latency, and pre-session crossings, as well as increases in avoidances. In both models, only ENBA-treated groups showed control level inter-trial interval crossings by day 14. Our findings suggest that ENBA, alone and as an adjunct to medical treatments, can improve behavioral and cognitive outcomes when given at delayed time points after GD intoxication.
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Affiliation(s)
- Joshua Harkins
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| | - Jeffrey Langston
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| | - Zora-Maya Keith
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| | - Crystal Munoz
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| | - Cindy Acon-Chen
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
| | - Tsung-Ming Shih
- Medical Toxicology Research Division, U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD, 21010-5400, USA.
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2
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Countermeasures in organophosphorus intoxication: pitfalls and prospects. Trends Pharmacol Sci 2022; 43:593-606. [DOI: 10.1016/j.tips.2022.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/14/2022] [Accepted: 04/17/2022] [Indexed: 11/24/2022]
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3
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Meads KL, Thomas TP, Langston JL, Myers TM, Shih TM. Evaluation of adenosine A1 receptor agonists as neuroprotective countermeasures against Soman intoxication in rats. Toxicol Appl Pharmacol 2021; 416:115466. [PMID: 33631229 DOI: 10.1016/j.taap.2021.115466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/16/2021] [Accepted: 02/18/2021] [Indexed: 11/20/2022]
Abstract
Soman, an organophosphorus (OP) compound, disrupts nervous system function through inactivation of acetylcholinesterase (AChE), the enzyme that breaks down acetylcholine at synapses. Left untreated, a state of prolonged seizure activity (status epilepticus, SE) is induced, causing widespread neuronal damage and associated cognitive and behavioral impairments. Previous research demonstrated that therapeutic stimulation of A1 adenosine receptors (A1ARs) can prevent or terminate soman-induced seizure. This study examined the ability of three potent A1AR agonists to provide neuroprotection and, ultimately, prevent observable cognitive and behavioral deficits following exposure to soman. Sprague Dawley rats were challenged with a seizure-inducing dose of soman (1.2 x LD50) and treated 1 min later with one of the following A1AR agonists: (6)-Cyclopentyladenosine (CPA), 2-Chloro-N6-cyclopentyladenosine (CCPA) or N-bicyclo(2.2.1)hept-2-yl-5'-chloro-5'-deoxyadenosine (cdENBA). An active avoidance shuttle box task was used to evaluate locomotor responses to aversive stimuli at 3, 7 and 14 days post-exposure. Animals treated with CPA, CCPA or cdENBA demonstrated a higher number of avoidance responses and a faster reaction to the aversive stimulus than the soman/saline control group across all three sessions. Findings suggest that A1AR agonism is a promising neuroprotective countermeasure, capable of preventing the long-term deficits in learning and memory that are characteristic of soman intoxication.
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Affiliation(s)
- Kristy L Meads
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010-5400, United States of America.
| | - Thaddeus P Thomas
- U.S. Army Research Laboratory, Aberdeen Proving Ground, MD 21005-5425, United States of America.
| | - Jeffrey L Langston
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010-5400, United States of America.
| | - Todd M Myers
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010-5400, United States of America.
| | - Tsung-Ming Shih
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010-5400, United States of America.
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Zhang L, Murata H, Amitai G, Smith PN, Matyjaszewski K, Russell AJ. Catalytic Detoxification of Organophosphorus Nerve Agents by Butyrylcholinesterase-Polymer-Oxime Bioscavengers. Biomacromolecules 2020; 21:3867-3877. [DOI: 10.1021/acs.biomac.0c00959] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Libin Zhang
- Center for Polymer-Based Protein Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Hironobu Murata
- Center for Polymer-Based Protein Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Gabriel Amitai
- Wohl Drug Discovery Institute, Nancy and Stephen Grand Israel National Center for Personalized Medicine (G-INCPM), Weizmann Institute of Science, Rehovot 760001, Israel
| | - Paige N. Smith
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Krzysztof Matyjaszewski
- Center for Polymer-Based Protein Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Alan J. Russell
- Center for Polymer-Based Protein Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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5
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Chambers JE, Dail MB, Meek EC. Oxime-mediated reactivation of organophosphate-inhibited acetylcholinesterase with emphasis on centrally-active oximes. Neuropharmacology 2020; 175:108201. [PMID: 32544483 DOI: 10.1016/j.neuropharm.2020.108201] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/02/2020] [Accepted: 06/11/2020] [Indexed: 01/25/2023]
Abstract
This review provides an overview of the global research leading to the large number of compounds developed as reactivators of acetylcholinesterase inhibited by a variety of organophosphate compounds, most of which are nerve agents but also some insecticides. A number of these organophosphates are highly toxic and effective therapy by reactivators contributes to saving lives. Two major challenges for more effective therapy with reactivators are identification of a broad spectrum reactivator efficacious against a variety of organophosphate structures, and a reactivator that can cross the blood-brain barrier to protect the brain. The most effective of the reactivators developed are the nucleophilic pyridinium oximes, which bear a permanent positive charge from the quaternary nitrogen in the pyridinium ring. The permanent positive charge retards the oximes from crossing the blood-brain barrier and therefore restoration of normal cholinergic function in the brain is unlikely. A number of laboratories have developed nucleophiles, mostly oximes, that are theorized to cross the blood-brain barrier by several strategies. At the present time, no reactivator is optimally broad spectrum across the wide group of organophosphate chemistries. Some oximes, including the substituted phenoxyalkyl pyridinium oximes invented by our laboratories, have the potential to provide neuroprotection in the brain and show evidence of efficacy against both nerve agent and insecticidal chemistries, so these novel oximes have promise for future development. This article is part of the special issue entitled 'Acetylcholinesterase Inhibitors: From Bench to Bedside to Battlefield'.
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Affiliation(s)
- Janice E Chambers
- Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762-6100, USA.
| | - Mary B Dail
- Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762-6100, USA
| | - Edward C Meek
- Center for Environmental Health Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762-6100, USA
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Faiz Norrrahim MN, Idayu Abdul Razak MA, Ahmad Shah NA, Kasim H, Wan Yusoff WY, Halim NA, Mohd Nor SA, Jamal SH, Ong KK, Zin Wan Yunus WM, Knight VF, Mohd Kasim NA. Recent developments on oximes to improve the blood brain barrier penetration for the treatment of organophosphorus poisoning: a review. RSC Adv 2020; 10:4465-4489. [PMID: 35495228 PMCID: PMC9049292 DOI: 10.1039/c9ra08599h] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 12/16/2019] [Indexed: 11/25/2022] Open
Abstract
Organophosphorus (OP) compounds are highly toxic synthetic compounds which have been used as pesticides and developed as warfare nerve agents. They represent a threat to both military and civilian populations. OP pesticides affect the nervous system and are thought to have caused at least 5 million deaths since their discovery in the 1930s. At present the treatment of OP nerve agent poisoning commonly involves the use of parenteral oximes. However, the blood brain barrier (BBB) remains a challenge in the delivery of oximes to the central nervous system (CNS). This is because almost all macromolecule drugs (including oximes) fail to pass through the BBB to reach the CNS structures. The presence of a permanent cationic charge in oximes has made these compounds inefficient in crossing the BBB. Thus, oximes are unable to reactivate acetylcholinesterase (AChE) in the CNS. Using current structural and mechanistic understanding of the BBB under both physiological and pathological conditions, it becomes possible to design delivery systems for oximes and other drugs that are able to cross the BBB effectively. This review summarises the recent strategies in the development of oximes which are capable of crossing the BBB to treat OP poisoning. Several new developments using oximes are reviewed along with their advantages and disadvantages. This review could be beneficial for future directions in the development of oxime and other drug delivery systems into the CNS. Organophosphorus (OP) compounds are highly toxic synthetic compounds which have been used as pesticides and developed as warfare nerve agents.![]()
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Zhang L, Baker SL, Murata H, Harris N, Ji W, Amitai G, Matyjaszewski K, Russell AJ. Tuning Butyrylcholinesterase Inactivation and Reactivation by Polymer-Based Protein Engineering. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1901904. [PMID: 31921563 PMCID: PMC6947490 DOI: 10.1002/advs.201901904] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/21/2019] [Indexed: 05/11/2023]
Abstract
Organophosphate nerve agents rapidly inhibit cholinesterases thereby destroying the ability to sustain life. Strong nucleophiles, such as oximes, have been used as therapeutic reactivators of cholinesterase-organophosphate complexes, but suffer from short half-lives and limited efficacy across the broad spectrum of organophosphate nerve agents. Cholinesterases have been used as long-lived therapeutic bioscavengers for unreacted organophosphates with limited success because they react with organophosphate nerve agents with one-to-one stoichiometries. The chemical power of nucleophilic reactivators is coupled to long-lived bioscavengers by designing and synthesizing cholinesterase-polymer-oxime conjugates using atom transfer radical polymerization and azide-alkyne "click" chemistry. Detailed kinetic studies show that butyrylcholinesterase-polymer-oxime activity is dependent on the electrostatic properties of the polymers and the amount of oxime within the conjugate. The covalent coupling of oxime-containing polymers to the surface of butyrylcholinesterase slows the rate of inactivation of paraoxon, a model nerve agent. Furthermore, when the enzyme is covalently inhibited by paraoxon, the covalently attached oxime induced inter- and intramolecular reactivation. Intramolecular reactivation will open the door to the generation of a new class of nerve agent scavengers that couple the speed and selectivity of biology to the ruggedness and simplicity of synthetic chemicals.
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Affiliation(s)
- Libin Zhang
- Center for Polymer‐Based Protein EngineeringCarnegie Mellon University5000 Forbes AvenuePittsburghPA15213USA
| | - Stefanie L. Baker
- Center for Polymer‐Based Protein EngineeringCarnegie Mellon University5000 Forbes AvenuePittsburghPA15213USA
- Department of Biomedical EngineeringCarnegie Mellon University5000 Forbes AvenuePittsburghPA15213USA
| | - Hironobu Murata
- Center for Polymer‐Based Protein EngineeringCarnegie Mellon University5000 Forbes AvenuePittsburghPA15213USA
| | - Nicholas Harris
- Center for Polymer‐Based Protein EngineeringCarnegie Mellon University5000 Forbes AvenuePittsburghPA15213USA
- Department of Biotechnology EngineeringORT Braude Academic CollegeKarmielPOB78Israel
| | - Weihang Ji
- Center for Polymer‐Based Protein EngineeringCarnegie Mellon University5000 Forbes AvenuePittsburghPA15213USA
| | - Gabriel Amitai
- Wohl Drug Discovery InstituteNancy and Stephen Grand Israel National Center for Personalized Medicine (G‐INCPM)Weizmann Institute of ScienceRehovot760001Israel
| | - Krzysztof Matyjaszewski
- Center for Polymer‐Based Protein EngineeringCarnegie Mellon University5000 Forbes AvenuePittsburghPA15213USA
- Department of ChemistryDepartment of Chemical EngineeringCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
| | - Alan J. Russell
- Center for Polymer‐Based Protein EngineeringCarnegie Mellon University5000 Forbes AvenuePittsburghPA15213USA
- Department of Biomedical EngineeringCarnegie Mellon University5000 Forbes AvenuePittsburghPA15213USA
- Department of ChemistryDepartment of Chemical EngineeringCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
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8
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Pringle RB, Meek EC, Chambers HW, Chambers JE. Neuroprotection From Organophosphate-Induced Damage by Novel Phenoxyalkyl Pyridinium Oximes in Rat Brain. Toxicol Sci 2019; 166:420-427. [PMID: 30496567 DOI: 10.1093/toxsci/kfy212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The nerve agents are extremely toxic organophosphates which lead to massive inhibition of acetylcholinesterase (AChE) in both the central and peripheral nervous systems. The currently approved pyridinium oxime reactivators of organophosphate-inhibited AChE (eg, 2-PAM in the United States) cannot penetrate the blood-brain barrier because of the permanent positive charge in the pyridinium ring. Therefore these current oximes cannot rescue inhibited AChE in the brain. Our laboratories have invented and patented a platform of substituted phenoxyalkyl pyridinium oximes that have been tested for efficacy as therapy within the brains of adult male rats which were challenged with a high sublethal dosage of highly relevant surrogates of sarin (nitrophenyl isopropyl methylphosphonate, NIMP) and VX (nitrophenyl ethyl methylphosphonate, NEMP). The histochemical astrocyte marker glial fibrillary acidic protein (GFAP) was investigated as an indication of neuropathology in two brain regions, the piriform cortex and the dentate gyrus of the hippocampus, which are regions known to be damaged by nerve agent toxicity. Rats treated with either NIMP or NEMP without therapy or with NIMP or NEMP plus 2-PAM therapy showed similar increases in GFAP compared with vehicle controls. However, the rats challenged with NIMP or NEMP plus therapy with our novel Oxime 20 (either a bromide or a mesylate salt) showed GFAP levels statistically undistinguishable from controls. These data provide highly supportive functional evidence of novel oxime entry into the brain. These novel oximes have the potential to provide central neuroprotection from organophosphate anticholinesterase-induced damage, which is a characteristic not displayed by most pyridinium oximes.
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Affiliation(s)
- Ronald B Pringle
- Center for Environmental Health Sciences.,Department of Basic Sciences, College of Veterinary Medicine
| | - Edward C Meek
- Center for Environmental Health Sciences.,Department of Basic Sciences, College of Veterinary Medicine
| | - Howard W Chambers
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, Mississippi 39762
| | - Janice E Chambers
- Center for Environmental Health Sciences.,Department of Basic Sciences, College of Veterinary Medicine
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9
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Atropine counteracts the depressive-like behaviour elicited by acute exposure to commercial chlorpyrifos in rats. Neurotoxicol Teratol 2019; 71:6-15. [DOI: 10.1016/j.ntt.2018.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 11/07/2018] [Accepted: 11/13/2018] [Indexed: 12/30/2022]
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Potentiation of antiseizure and neuroprotective efficacy of standard nerve agent treatment by addition of tariquidar. Neurotoxicology 2018; 68:167-176. [DOI: 10.1016/j.neuro.2018.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/08/2018] [Accepted: 08/15/2018] [Indexed: 12/25/2022]
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11
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Scholl EA, Miller-Smith SM, Bealer SL, Lehmkuhle MJ, Ekstrand JJ, Dudek FE, McDonough JH. Age-dependent behaviors, seizure severity and neuronal damage in response to nerve agents or the organophosphate DFP in immature and adult rats. Neurotoxicology 2018; 66:10-21. [PMID: 29510177 PMCID: PMC5996394 DOI: 10.1016/j.neuro.2018.02.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 02/07/2018] [Accepted: 02/27/2018] [Indexed: 01/15/2023]
Abstract
Exposure to nerve agents (NAs) and other organophosphates (OPs) can initiate seizures that rapidly progress to status epilepticus (SE). While the electrographic and neuropathological sequelae of SE evoked by NAs and OPs have been characterized in adult rodents, they have not been adequately investigated in immature animals. In this study postnatal day (PND) 14, 21 and 28 rat pups, along with PND70 animals as adult controls, were exposed to NAs (sarin, VX) or another OP (diisopropylfluorophosphate, DFP). We then evaluated behavioral and electrographic (EEG) correlates of seizure activity, and performed neuropathology using Fluoro-Jade B. Although all immature rats exhibited behaviors that are often characterized as seizures, the incidence, duration, and severity of the electrographic seizure activity were age-dependent. No (sarin and VX) or brief (DFP) EEG seizure activity was evoked in PND14 rats, while SE progressively increased in severity as a function of age in PND21, 28 and 70 animals. Fluoro-Jade B staining was observed in multiple brain regions of animals that exhibited prolonged seizure activity. Neuronal injury in PND14 animals treated with DFP was lower than in older animals and absent in rats exposed to sarin or VX. In conclusion, we found that NAs and an OP provoked robust SE and neuronal injury similar to adults in PND21 and PND28, but not in PND14, rat pups. Convulsive behaviors were often present independent of EEG seizures and were unaccompanied by neuronal damage. These differential responses should be considered when investigating medical countermeasures for NA and OP exposure in pediatric populations.
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Affiliation(s)
- Erika A Scholl
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA
| | - Stephanie M Miller-Smith
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 21010-5400 USA
| | - Steven L Bealer
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA; Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, 84108 USA
| | - Mark J Lehmkuhle
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA; Epitel, Inc., Salt Lake City, UT, 84111 USA
| | - Jeffrey J Ekstrand
- Department of Pediatrics, University of Utah, Salt Lake City, UT, 84108 USA
| | - F Edward Dudek
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA
| | - John H McDonough
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 21010-5400 USA.
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Winkler JL, Skovira JW, Kan RK. Anticonvulsant efficacy of antihistamine cyproheptadine in rats exposed to the chemical warfare nerve agent soman. Neurotoxicology 2017; 58:153-160. [DOI: 10.1016/j.neuro.2016.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 11/15/2022]
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Buchwald P, Bodor N. Brain-Targeting Chemical Delivery Systems and Their Cyclodextrin-Based Formulations in Light of the Contributions of Marcus E. Brewster. J Pharm Sci 2016; 105:2589-2600. [DOI: 10.1016/j.xphs.2016.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/07/2016] [Accepted: 04/07/2016] [Indexed: 11/29/2022]
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14
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Masson P. Novel approaches in prophylaxis/pretreatment and treatment of organophosphorus poisoning. PHOSPHORUS SULFUR 2016. [DOI: 10.1080/10426507.2016.1211652] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Patrick Masson
- Neuropharmacology Laboratory, Kazan Federal University, Kazan, Russian Federation
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Voicu VA, Medvedovici AV, Sakurada K, Ohta H, Rădulescu FȘ, Miron DS. The forgotten or underestimated relevance of biopharmaceutical-based assessments for the oral absorption studies of oxime reactivators. Expert Opin Drug Metab Toxicol 2016; 12:743-52. [DOI: 10.1080/17425255.2016.1179282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Victor A. Voicu
- Department of Pharmacology, Toxicology and Clinical Psychopharmacology, University of Medicine and Pharmacy ‘Carol Davilla’, Bucharest, Romania
- Medical Science Section, Romanian Academy, Bucharest, Romania
| | | | - Koichi Sakurada
- Department of Forensic Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hikoto Ohta
- Department of Forensic Chemistry, Toxicology Section, National Research Institute of Police Science, National Police Agency, Kashiwa City, Chiba, Japan
| | | | - Dalia Simona Miron
- Faculty of Pharmacy, University of Medicine and Pharmacy Carol Davila, Bucharest, Romania
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Schmidt HR, Radić Z, Taylor P, Fradinger EA. Quaternary and tertiary aldoxime antidotes for organophosphate exposure in a zebrafish model system. Toxicol Appl Pharmacol 2015; 284:197-203. [DOI: 10.1016/j.taap.2015.02.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/28/2015] [Accepted: 02/05/2015] [Indexed: 11/29/2022]
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17
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Post-exposure treatment of VX poisoned guinea pigs with the engineered phosphotriesterase mutant C23: A proof-of-concept study. Toxicol Lett 2014; 231:45-54. [DOI: 10.1016/j.toxlet.2014.09.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/01/2014] [Accepted: 09/03/2014] [Indexed: 11/21/2022]
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Sit RK, Fokin VV, Amitai G, Sharpless KB, Taylor P, Radić Z. Imidazole aldoximes effective in assisting butyrylcholinesterase catalysis of organophosphate detoxification. J Med Chem 2014; 57:1378-89. [PMID: 24571195 PMCID: PMC4167068 DOI: 10.1021/jm401650z] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Intoxication
by organophosphate (OP) nerve agents and pesticides
should be addressed by efficient, quickly deployable countermeasures
such as antidotes reactivating acetylcholinesterase or scavenging
the parent OP. We present here synthesis and initial in vitro characterization of 14 imidazole aldoximes and their structural
refinement into three efficient reactivators of human butyrylcholinesterase
(hBChE) inhibited covalently by nerve agent OPs, sarin, cyclosarin,
VX, and the OP pesticide metabolite, paraoxon. Rapid reactivation
of OP–hBChE conjugates by uncharged and nonprotonated tertiary
imidazole aldoximes allows the design of a new OP countermeasure by
conversion of hBChE from a stoichiometric to catalytic OP bioscavenger
with the prospect of oral bioavailability and central nervous system
penetration. The enhanced in vitro reactivation efficacy
determined for tertiary imidazole aldoximes compared to that of their
quaternary N-methyl imidazolium analogues is attributed
to ion pairing of the cationic imidazolium with Asp 70, altering a
reactive alignment of the aldoxime with the phosphorus in the OP–hBChE
conjugate.
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Affiliation(s)
- Rakesh K Sit
- Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
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Worek F, Seeger T, Goldsmith M, Ashani Y, Leader H, Sussman JS, Tawfik D, Thiermann H, Wille T. Efficacy of the rePON1 mutant IIG1 to prevent cyclosarin toxicity in vivo and to detoxify structurally different nerve agents in vitro. Arch Toxicol 2014; 88:1257-66. [DOI: 10.1007/s00204-014-1204-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 01/16/2014] [Indexed: 01/09/2023]
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Moshiri M, Darchini-Maragheh E, Balali-Mood M. Advances in toxicology and medical treatment of chemical warfare nerve agents. ACTA ACUST UNITED AC 2012; 20:81. [PMID: 23351280 PMCID: PMC3556041 DOI: 10.1186/2008-2231-20-81] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 11/17/2012] [Indexed: 11/10/2022]
Abstract
Organophosphorous (OP) Nerve agents (NAs) are known as the deadliest chemical warfare agents. They are divided into two classes of G and V agents. Most of them are liquid at room temperature. NAs chemical structures and mechanisms of actions are similar to OP pesticides, but their toxicities are higher than these compounds. The main mechanism of action is irreversible inhibition of Acetyl Choline Esterase (AChE) resulting in accumulation of toxic levels of acetylcholine (ACh) at the synaptic junctions and thus induces muscarinic and nicotinic receptors stimulation. However, other mechanisms have recently been described. Central nervous system (CNS) depression particularly on respiratory and vasomotor centers may induce respiratory failure and cardiac arrest. Intermediate syndrome after NAs exposure is less common than OP pesticides poisoning. There are four approaches to detect exposure to NAs in biological samples: (I) AChE activity measurement, (II) Determination of hydrolysis products in plasma and urine, (III) Fluoride reactivation of phosphylated binding sites and (IV) Mass spectrometric determination of cholinesterase adducts. The clinical manifestations are similar to OP pesticides poisoning, but with more severity and fatalities. The management should be started as soon as possible. The victims should immediately be removed from the field and treatment is commenced with auto-injector antidotes (atropine and oximes) such as MARK I kit. A 0.5% hypochlorite solution as well as novel products like M291 Resin kit, G117H and Phosphotriesterase isolated from soil bacterias, are now available for decontamination of NAs. Atropine and oximes are the well known antidotes that should be infused as clinically indicated. However, some new adjuvant and additional treatment such as magnesium sulfate, sodium bicarbonate, gacyclidine, benactyzine, tezampanel, hemoperfusion, antioxidants and bioscavengers have recently been used for OP NAs poisoning.
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Affiliation(s)
- Mohammd Moshiri
- Medical Toxicology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
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de Araujo Furtado M, Rossetti F, Chanda S, Yourick D. Exposure to nerve agents: from status epilepticus to neuroinflammation, brain damage, neurogenesis and epilepsy. Neurotoxicology 2012; 33:1476-1490. [PMID: 23000013 DOI: 10.1016/j.neuro.2012.09.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Revised: 07/25/2012] [Accepted: 09/03/2012] [Indexed: 12/17/2022]
Abstract
Epilepsy is a common neurological disorder characterized by an initial injury due to stroke, traumatic brain injury, brain infection, or febrile seizures causing status epilepticus (SE). This phenomenon precedes recurrent (secondary) seizures, the latent period (period without seizures) and downstream appearance of spontaneous recurrent seizures (SRS). Epilepsy inducers include the organophosphorous (OP) compounds modified as chemical warfare nerve agents, such as soman. SE induced by soman is a result of cholinergic system hyperactivity caused by the irreversible inhibition of acetylcholinesterase, and the subsequent increase in the amount of the neurotransmitter acetylcholine at central and peripheral sites. SE leads to profound, permanent, complex and widespread brain damage and associated cognitive and behavioral deficits, accompanied by impaired neurogenesis. Several anticonvulsant and neuroprotective strategies have been studied in order to avoid the epileptogenesis which occurs after SE caused by soman exposure. In recent studies, we showed that SRS occur post-soman exposure and neuropathology can be reduced with diazepam (DZP) and valproic acid (VPA) when administered in combination treatment. These effects are accompanied by neurogenesis seen 15 days post-exposure in the hippocampal dentate gyrus (DG). This review discusses several findings about epilepsy induced by soman exposure such as behavioral changes, EEG anomalies, neuropathology, neuroinflammation, neurogenesis, possible circuitry changes and current strategies for treatment. The soman seizure model is an important model of temporal lobe epilepsy (TLE) and comparable in certain respects with well studied models in the literature such as pilocarpine and kainic acid. All these models together allow for a greater understanding of the different mechanisms of seizure induction, propagation and options for treatment. These studies are very necessary for current military and civilian treatment regimens, against OP nerve agent exposure, which fail to prevent SE resulting in severe neuropathology and epilepsy.
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Affiliation(s)
- Marcio de Araujo Furtado
- Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Franco Rossetti
- Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Soma Chanda
- Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Debra Yourick
- Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States.
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Khan FA, Campbell AJ, Hoyt B, Herdman C, Ku T, Thangavelu S, Gordon RK. Oxidative mechanisms for the biotransformation of 1-methyl-1,6-dihydropyridine-2-carbaldoxime to pralidoxime chloride. Life Sci 2011; 89:911-7. [PMID: 21989207 DOI: 10.1016/j.lfs.2011.09.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 08/02/2011] [Accepted: 09/13/2011] [Indexed: 01/02/2023]
Abstract
AIMS Due to pralidoxime chloride's (2-PAM) positive charge, it's penetration through the blood brain barrier (BBB) and reactivation of organophosphate (OP) inhibited central nervous system (CNS) acetylcholinesterase (AChE) is poor. The results of CNS inhibited AChE are seizures. Pro-2-PAM (1-methyl-1,6-dihydropyridine-2-carbaldoxime), a pro-drug of 2-PAM, due to higher hydrophobicity, penetrates the BBB better but must be oxidized to 2-PAM, the active form of the oxime to reactivate CNS AChE in order to abrogate seizures. In this study, we characterize the in vivo mechanism of pro-2-PAM oxidation. MAIN METHODS A high pressure liquid chromatography (HPLC) assay was developed to quantify the conversion of pro-2-PAM to 2-PAM. NADPH oxidase activity was measured by a photo-luminescence assay using lucigenin substrate. Upon analysis, the rate of NADPH induced oxidation suggested that an alternate mechanism may be involved. Therefore, various enzyme co-factors of oxidation-reduction enzyme systems were evaluated, including nicotinamide adenine dinucleotide (NAD), nicotinamide adenine dinucleotide phosphate (NADP), flavin adenine dinucleotide (FAD), riboflavin 5'-phosphate (FMN), and riboflavin. Next, a spectrophotometric assay was developed to measure the conversion of pro-2-PAM to 2-PAM in the presence of riboflavin. KEY FINDINGS In guinea pig brain homogenate, diphenyleneiodonium (DPI), a specific NADPH oxidase inhibitor, reduced pro-2-PAM to 2-PAM conversion to less than 25%. In contrast, riboflavin, FAD, and FMN rapidly oxidized all pro-2-PAM to 2-PAM in an in vitro assay. Riboflavin oxidized pro-2-PAM reactivated diisopropylfluorophosphate (DFP) inhibited AChE. SIGNIFICANCE The present study shows that pro-2-PAM was rapidly oxidized by riboflavin to 2-PAM, which reactivated organophosphate (OP)-inhibited AChE.
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Affiliation(s)
- Farhat A Khan
- Department of Regulated Laboratories, Division of Regulated Activities, Silver Spring, MD 20910, United States.
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