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Voros C, Dias J, Timperley CM, Nachon F, Brown RCD, Baati R. The risk associated with organophosphorus nerve agents: from their discovery to their unavoidable threat, current medical countermeasures and perspectives. Chem Biol Interact 2024; 395:110973. [PMID: 38574837 DOI: 10.1016/j.cbi.2024.110973] [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: 01/18/2024] [Revised: 03/13/2024] [Accepted: 03/21/2024] [Indexed: 04/06/2024]
Abstract
The first organophosphorus nerve agent was discovered accidently during the development of pesticides, shortly after the first use of chemical weapons (chlorine, phosgene) on the battlefield during World War I. Despite the Chemical Weapons Convention banning these substances, they have still been employed in wars, terrorist attacks or political assassinations. Characterised by their high lethality, they target the nervous system by inhibiting the acetylcholinesterase (AChE) enzyme, preventing neurotransmission, which, if not treated rapidly, inevitably leads to serious injury or the death of the person intoxicated. The limited efficacy of current antidotes, known as AChE reactivators, pushes research towards new treatments. Numerous paths have been explored, from modifying the original pyridinium oximes to developing hybrid reactivators seeking a better affinity for the inhibited AChE. Another crucial approach resides in molecules more prone to cross the blood-brain barrier: uncharged compounds, bio-conjugated reactivators or innovative formulations. Our aim is to raise awareness on the threat and toxicity of organophosphorus nerve agents and to present the main synthetic efforts deployed since the first AChE reactivator, to tackle the task of efficiently treating victims of these chemical warfare agents.
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Affiliation(s)
- Camille Voros
- Ecole de Chimie Polymère et Matériaux ECPM, Université de Strasbourg, ICPEES UMR CNRS 7515, 25 rue Becquerel, F-67087, Strasbourg, France.
| | - José Dias
- Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, F-91220 Brétigny-sur-Orge, France
| | - Christopher M Timperley
- Chemical, Biological and Radiological (CBR) Division, Dstl, Porton Down, Salisbury, Wiltshire, SP4 0JQ, UK.
| | - Florian Nachon
- Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, F-91220 Brétigny-sur-Orge, France
| | - Richard C D Brown
- Department of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
| | - Rachid Baati
- Ecole de Chimie Polymère et Matériaux ECPM, Université de Strasbourg, ICPEES UMR CNRS 7515, 25 rue Becquerel, F-67087, Strasbourg, France; OPGS Pharmaceuticals, Paris BioTech Santé, 24 rue du Faubourg Saint-Jacques, F-75014, Paris, France.
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2
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Non-quaternary oximes detoxify nerve agents and reactivate nerve agent-inhibited human butyrylcholinesterase. Commun Biol 2021; 4:573. [PMID: 33990679 PMCID: PMC8121814 DOI: 10.1038/s42003-021-02061-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 03/31/2021] [Indexed: 11/08/2022] Open
Abstract
Government-sanctioned use of nerve agents (NA) has escalated dramatically in recent years. Oxime reactivators of organophosphate (OP)-inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) serve as antidotes toward poisoning by OPNAs. The oximes used as therapeutics are quaternary compounds that cannot penetrate the blood-brain barrier (BBB). There remains an urgent need for the development of next generation OPNA therapeutics. We have developed two high-throughput screening (HTS) assays using a fluorogenic NA surrogate, O-ethyl methylphosphonyl O-4-methyl-3-cyano-coumarin (EMP-MeCyC). EMP-MeCyC detoxification and EMP-BChE reactivation screening campaigns of ~155,000 small molecules resulted in the identification of 33 nucleophile candidates, including non-quaternary oximes. Four of the oximes were reactivators of both Sarin- and VX-inhibited BChE and directly detoxified Sarin. One oxime also detoxified VX. The novel reactivators included a non-quaternary pyridine amidoxime, benzamidoxime, benzaldoxime and a piperidyl-ketoxime. The VX-inhibited BChE reactivation reaction rates by these novel molecules were similar to those observed with known bis-quaternary reactivators and faster than mono-quaternary pyridinium oximes. Notably, we discovered the first ketoxime reactivator of OP-ChEs and detoxifier of OPNAs. Preliminary toxicological studies demonstrated that the newly discovered non-quaternary oximes were relatively non-toxic in mice. The discovery of unique non-quaternary oximes opens the door to the design of novel therapeutics and decontamination agents following OPNA exposure.
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Hayes TR, Chao CK, Blecha JE, Huynh TL, Zinn KR, Thompson CM, Gerdes JM, VanBrocklin HF. Biological Distribution and Metabolic Profiles of Carbon-11 and Fluorine-18 Tracers of VX- and Sarin-Analogs in Sprague-Dawley Rats. Chem Res Toxicol 2020; 34:63-69. [PMID: 33373198 PMCID: PMC7818893 DOI: 10.1021/acs.chemrestox.0c00237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Organophosphorus esters (OPs) were originally developed as pesticides but were repurposed as easily manufactured, inexpensive, and highly toxic chemical warfare agents. Acute OP toxicity is primarily due to inhibition of acetylcholinesterase (AChE), an enzyme in the central and peripheral nervous system. OP inhibition of AChE can be reversed using oxime reactivators but many show poor CNS penetration, indicating a need for new clinically viable reactivators. However, challenges exist on how to best measure restored AChE activity in vivo and assess the reactivating agent efficacy. This work reports the development of molecular imaging tools using radiolabeled OP analog tracers that are less toxic to handle in the laboratory, yet inhibit AChE in a similar fashion to the actual OPs. Carbon-11 and fluorine-18 radiolabeled analog tracers of VX and sarin OP agents were prepared. Following intravenous injection in normal Sprague-Dawley rats (n = 3-4/tracer), the tracers were evaluated and compared using noninvasive microPET/CT imaging, biodistribution assay, and arterial blood analyses. All showed rapid uptake and stable retention in brain, heart, liver, and kidney tissues determined by imaging and biodistribution. Lung uptake of the sarin analog tracers was elevated, 2-fold and 4-fold higher uptake at 5 and 30 min, respectively, compared to that for the VX analog tracers. All tracers rapidly bound to red blood cells (RBC) and blood proteins as measured in the biodistribution and arterial blood samples. Analysis of the plasma soluble activity (nonprotein/cell bound activity) showed only 1-6% parent tracer and 88-95% of the activity in the combined solid fractions (RBC and protein bound) as early as 0.5 min post injection. Multivariate analysis of tracer production yield, molar activity, brain uptake, brain area under the curve over 0-15 min, and the amount of parent tracer in the plasma at 5 min revealed the [18F]VX analog tracer had the most favorable values for each metric. This tracer was considered the more optimal tracer relative to the other tracers studied and suitable for future in vivo OP exposure and reactivation studies.
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Affiliation(s)
- Thomas R Hayes
- Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, California 94143, United States
| | - Chih-Kai Chao
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana 59812, United States
| | - Joseph E Blecha
- Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, California 94143, United States
| | - Tony L Huynh
- Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, California 94143, United States
| | - Kurt R Zinn
- Departments of Radiology, Small Animal Clinical Sciences, and Biomedical Engineering; Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Charles M Thompson
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana 59812, United States
| | - John M Gerdes
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana 59812, United States
| | - Henry F VanBrocklin
- Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, California 94143, United States
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4
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Koenig JA, Acon Chen C, Shih TM. Development of a Larval Zebrafish Model for Acute Organophosphorus Nerve Agent and Pesticide Exposure and Therapeutic Evaluation. TOXICS 2020; 8:toxics8040106. [PMID: 33213094 PMCID: PMC7712847 DOI: 10.3390/toxics8040106] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 10/30/2020] [Accepted: 11/12/2020] [Indexed: 01/03/2023]
Abstract
Organophosphorus compound exposure remains a present threat through agricultural accidents, warfare, or terrorist activity. The primary mechanism of organophosphorus toxicity is through inhibition of the enzyme acetylcholinesterase, with current emergency treatment including anticholinergics, benzodiazepines, and oxime reactivators. However, a need for more effective and broadly acting countermeasures remains. This study aimed to develop larval zebrafish as a high-throughput model for evaluating novel therapeutics against acute organophosphorus exposure. Larval zebrafish at six days post-fertilization were exposed to acute concentrations of seven organophosphorus compounds and treated with one of three oximes. Lethality studies indicated similar relative toxicity to that seen in the established rodent model, with chemical warfare agents proving more lethal than organophosphorus pesticides. Additionally, the organophosphorus-specific response for oxime reactivation of acetylcholinesterase was comparable to what has been previously reported. Behavioral studies measuring the visual motor response demonstrated greater efficacy for centrally acting oxime compounds than for those that are contained to the peripheral tissue. Overall, these results support the use of this larval zebrafish model as a high-throughput screening platform for evaluating novel treatments following acute organophosphorus exposure.
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Affiliation(s)
| | | | - Tsung-Ming Shih
- Correspondence: ; Tel.: +1-410-436-3414; Fax: +1-410-436-2690
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5
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Machamer JB, Apland JP, Winner BM, Wolfe SE, Pagarigan KT, Bounader KM, Kasten SA, Adler M, McNutt PM. Functional basis for dose-dependent antagonism of rat and rabbit neuromuscular transmission by the bis-pyridinium oxime MMB4. Arch Toxicol 2020; 94:3877-3891. [DOI: 10.1007/s00204-020-02858-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/14/2020] [Indexed: 01/30/2023]
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Hayes TR, Blecha JE, Chao CK, Huynh TL, VanBrocklin HF, Zinn KR, Taylor PW, Gerdes JM, Thompson CM. Positron emission tomography evaluation of oxime countermeasures in live rats using the tracer O-(2-[ 18 F]fluoroethyl)-O-(p-nitrophenyl)methylphosphonate [ 18 F]-VXS. Ann N Y Acad Sci 2020; 1479:180-195. [PMID: 32436233 DOI: 10.1111/nyas.14363] [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] [Received: 01/24/2020] [Revised: 04/13/2020] [Accepted: 04/17/2020] [Indexed: 11/27/2022]
Abstract
Oxime antidotes regenerate organophosphate-inhibited acetylcholinesterase (AChE). Although they share a common mechanism of AChE reactivation, the rate and amount of oxime that enters the brain are critical to the efficacy, a process linked to the oxime structure and charge. Using a platform based on the organophosphate [18 F]-VXS as a positron emission tomography tracer for active AChE, the in vivo distribution of [18 F]-VXS was evaluated after an LD50 dose (250 μg/kg) of the organophosphate paraoxon (POX) and following oximes as antidotes. Rats given [18 F]-VXS tracer alone had significantly higher radioactivity (two- to threefold) in the heart and lung than rats given LD50 POX at 20 or 60 min prior to [18 F]-VXS. When rats were given LD50 POX followed by 2-PAM (cationic), RS194b (ionizable), or monoisonitrosoacetone (MINA) (neutral), central nervous system (CNS) radioactivity returned to levels at or above untreated naive rats (no POX), whereas CNS radioactivity did not increase in rats given the dication oximes HI-6 or MMB-4. MINA showed a significant, pairwise increase in CNS brain radioactivity compared with POX-treated rats. This new in vivo dynamic platform using [18 F]-VXS tracer measures and quantifies peripheral and CNS relative changes in AChE availability after POX exposure and is suitable for comparing oxime delivery and AChE reactivation in rats.
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Affiliation(s)
- Thomas R Hayes
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California
| | - Joseph E Blecha
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California
| | - Chih-Kai Chao
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana
| | - Tony L Huynh
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California
| | - Henry F VanBrocklin
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California
| | - Kurt R Zinn
- Departments of Radiology, Small Animal Clinical Sciences, and Biomedical Engineering, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, Michigan
| | - Palmer W Taylor
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California
| | - John M Gerdes
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana
| | - Charles M Thompson
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana
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7
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da Silva FD, Nogara PA, Braga MM, Piccoli BC, Rocha JBT. Molecular docking analysis of acetylcholinesterase corroborates the protective effect of pralidoxime against chlorpyrifos-induced behavioral and neurochemical impairments in Nauphoeta cinerea. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.comtox.2018.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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8
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Matson LM, Lee-Stubbs RB, Cadieux CL, Koenig JA, Ardinger CE, Chandler J, Johnson EA, Hoard-Fruchey HM, Shih TMA, Cerasoli DM, McDonough JH. Assessment of mouse strain differences in baseline esterase activities and toxic response to sarin. Toxicology 2018; 410:10-15. [PMID: 30172647 DOI: 10.1016/j.tox.2018.08.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/09/2018] [Accepted: 08/27/2018] [Indexed: 11/24/2022]
Abstract
Genetics likely play a role in various responses to nerve agent (NA) exposure, as genetic background plays an important role in behavioral, neurological, and physiological responses. This study uses different mouse strains to identify if mouse strain differences in sarin exposure exist. In Experiment 1, basal levels of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and carboxylesterase (CE) were measured in different strains of naïve mice to account for potential pharmacokinetic determinants of individual differences. In Experiment 2, median lethal dose (MLD) levels were estimated in 8 inbred mouse strains following subcutaneous (s.c.) administration of sarin. Few strain or sex differences in esterase activity levels were observed, with the exception of erythrocyte AChE activity in the C57BL/6J strain. Both sex and strain differences in toxicity were observed, with the most resistant strains being the BALB/cByJ and FVB/NJ strains and the most sensitive strain being the DBA/2J strain. These findings can be expanded to explore pathways involved in NA response, which may provide an avenue to develop therapeutics for preventing and treating the damaging effects of NA exposure.
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Affiliation(s)
- Liana M Matson
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
| | - Robyn B Lee-Stubbs
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
| | - C Lin Cadieux
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
| | - Jeffrey A Koenig
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
| | - Cherish E Ardinger
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
| | - Jessica Chandler
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
| | - Erik A Johnson
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
| | - Heidi M Hoard-Fruchey
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
| | - Tsung-Ming A Shih
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
| | - Doug M Cerasoli
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States
| | - John H McDonough
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
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9
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Moffett MC, McDonough JH, McMonagle JD, Myers TM. Behavioral, Pharmacokinetic, and Cardiovascular Evaluation of Candidate Oximes in African Green Monkeys. Int J Toxicol 2018; 37:352-363. [DOI: 10.1177/1091581818779362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Oxime reactivators are critical antidotes after organophosphate pesticide or nerve agent poisoning, directly restoring the function of inhibited acetylcholinesterase. In the continuing search for more broad-spectrum acetylcholinesterase reactivators, this study evaluated one of the leading next-generation oxime reactivators: methoxime, (1,1′-trimethylene bis[4-(hydroxyimino)methyl]pyridinium dichloride (MMB-4). The pharmacokinetics of both salts of MMB-4 (dichloride [2Cl] and dimethanesulphonate [DMS]) were characterized across a range of relevant doses (19, 58, and 116 µmol/kg, intramuscular) in a nonhuman primate model (male African green monkeys), and only subtle differences were observed between the salts. Additionally, the behavioral and cardiovascular safety of these MMB-4 salts was compared directly to other available oximes (HI-6 2Cl, HI-6 DMS, and pyridine-2-aldoxime chloride (2-PAM Cl)) at comparable projected doses. Automated operant behavioral tests were used to examine attention, motivation, visual discrimination, concept execution, and fine motor coordination after high doses of all oxime salts, and of all oximes studied, only the highest dose of 2-PAM Cl (447 µmol/kg) disrupted behavioral performance. Likewise, the effects of a range of doses of MMB-4 2Cl or DMS, HI-6 2Cl or DMS, or 2-PAM Cl on cardiovascular parameters were measured in African green monkeys implanted with telemetry devices. Only a small transient decrease in pulse pressure was observed following administration of the highest dose of MMB-4 DMS (116 µmol/kg). Thus, MMB-4 salts, up to the 9× equivalent of a projected autoinjector dose in humans, did not produce behavioral or cardiovascular toxicity in African green monkeys in the current study, and the pharmacokinetic parameters were orderly and predictable.
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Affiliation(s)
- Mark C. Moffett
- United States Army Medical Research Institute of Chemical Defense, MD, USA
| | - John H. McDonough
- United States Army Medical Research Institute of Chemical Defense, MD, USA
| | | | - Todd M. Myers
- United States Army Medical Research Institute of Chemical Defense, MD, USA
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10
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Strauss V, Rey Moreno MC, Vogt J, Dammann M, Schneider S, Gröters S, van Ravenzwaay B. Acetylcholinesterase measurement in various brain regions and muscles of juvenile, adolescent, and adult rats. Toxicol Mech Methods 2017; 27:666-676. [DOI: 10.1080/15376516.2017.1349849] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Volker Strauss
- Department of Experimental Toxicology and Ecology, BASF SE, Ludwigshafen, Germany
| | | | - Jeanette Vogt
- Department of Experimental Toxicology and Ecology, BASF SE, Ludwigshafen, Germany
| | - Martina Dammann
- Department of Experimental Toxicology and Ecology, BASF SE, Ludwigshafen, Germany
| | - Steffen Schneider
- Department of Experimental Toxicology and Ecology, BASF SE, Ludwigshafen, Germany
| | - Sibylle Gröters
- Department of Experimental Toxicology and Ecology, BASF SE, Ludwigshafen, Germany
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11
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Amitai G, Gez R, Raveh L, Bar-Ner N, Grauer E, Chapman S. Novel bifunctional hybrid small molecule scavengers for mitigating nerve agents toxicity. Chem Biol Interact 2016; 259:187-204. [DOI: 10.1016/j.cbi.2016.04.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 01/09/2023]
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12
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Snider TH, Wilhelm CM, Babin MC, Platoff GE, Yeung DT. Assessing the therapeutic efficacy of oxime therapies against percutaneous organophosphorus pesticide and nerve agent challenges in the Hartley guinea pig. J Toxicol Sci 2016; 40:759-75. [PMID: 26558457 DOI: 10.2131/jts.40.759] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Given the rapid onset of symptoms from intoxication by organophosphate (OP) compounds, a quick-acting, efficacious therapeutic regimen is needed. A primary component of anti-OP therapy is an oxime reactivator to rescue OP-inhibited acetylcholinesterases. Male guinea pigs, clipped of hair, received neat applications of either VR, VX, parathion, or phorate oxon (PHO) at the 85(th) percentile lethal dose, and, beginning with presentation of toxicosis, received the human equivalent dose therapy by intramuscular injection with two additional follow-on treatments at 3-hr intervals. Each therapy consisted of atropine free base at 0.4 mg/kg followed by one of eight candidate oximes. Lethality rates were obtained at 24 hr after VR, VX and PHO challenges, and at 48 hr after challenge with parathion. Lethality rates among symptomatic, oxime-treated groups were compared with that of positive control (OP-challenged and atropine-only treated) guinea pigs composited across the test days. Significant (p ≤ 0.05) protective therapy was afforded by 1,1-methylene bis(4(hydroxyimino- methyl)pyridinium) dimethanesulfonate (MMB4 DMS) against challenges of VR (p ≤ 0.001) and VX (p ≤ 0.05). Lethal effects of VX were also significantly (p ≤ 0.05) mitigated by treatments with oxo-[[1-[[4-(oxoazaniumylmethylidene)pyridin-1-yl]methoxymethyl]pyridin-4-ylidene]methyl]azanium dichloride (obidoxime Cl2) and 1-(((4-(aminocarbonyl) pyridinio)methoxy)methyl)-2,4-bis((hydroxyimino)methyl)pyridinium dimethanesulfonate (HLö-7 DMS). Against parathion, significant protective therapy was afforded by obidoxime dichloride (p ≤ 0.001) and 1,1'-propane-1,3-diylbis{4-[(E)-(hydroxyimino)methyl]pyridinium} dibromide (TMB-4, p ≤ 0.01). None of the oximes evaluated was therapeutically effective against PHO. Across the spectrum of OP chemicals tested, the oximes that offered the highest level of therapy were MMB4 DMS and obidoxime dichloride.
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13
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Koenig JA, Dao TL, Kan RK, Shih TM. Zebrafish as a model for acetylcholinesterase-inhibiting organophosphorus agent exposure and oxime reactivation. Ann N Y Acad Sci 2016; 1374:68-77. [PMID: 27123828 DOI: 10.1111/nyas.13051] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/25/2016] [Accepted: 03/02/2016] [Indexed: 01/05/2023]
Abstract
The current research progression efforts for investigating novel treatments for exposure to organophosphorus (OP) compounds that inhibit acetylcholinesterase (AChE), including pesticides and chemical warfare nerve agents (CWNAs), rely solely on in vitro cell assays and in vivo rodent models. The zebrafish (Danio rerio) is a popular, well-established vertebrate model in biomedical research that offers high-throughput capabilities and genetic manipulation not readily available with rodents. A number of research studies have investigated the effects of subacute developmental exposure to OP pesticides in zebrafish, observing detrimental effects on gross morphology, neuronal development, and behavior. Few studies, however, have utilized this model to evaluate treatments, such as oxime reactivators, anticholinergics, or anticonvulsants, following acute exposure. Preliminary work has investigated the effects of CWNA exposure. The results clearly demonstrated relative toxicity and oxime efficacy similar to that reported for the rodent model. This review surveys the current literature utilizing zebrafish as a model for OP exposure and highlights its potential use as a high-throughput system for evaluating AChE reactivator antidotal treatments to acute pesticide and CWNA exposure.
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Affiliation(s)
- Jeffrey A Koenig
- Pharmacology Branch, Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Thuy L Dao
- Pharmacology Branch, Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Robert K Kan
- Pharmacology Branch, Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Tsung-Ming Shih
- Pharmacology Branch, Research Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
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14
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Cadieux CL, Wang H, Zhang Y, Koenig JA, Shih TM, McDonough J, Koh J, Cerasoli D. Probing the activity of a non-oxime reactivator for acetylcholinesterase inhibited by organophosphorus nerve agents. Chem Biol Interact 2016; 259:133-141. [PMID: 27062893 DOI: 10.1016/j.cbi.2016.04.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 03/23/2016] [Accepted: 04/04/2016] [Indexed: 11/16/2022]
Abstract
Currently fielded treatments for nerve agent intoxication include atropine, an acetylcholine receptor antagonist, and pralidoxime (2PAM), a small molecule reactivator of acetylcholinesterase (AChE). 2PAM reactivates nerve agent-inhibited AChE via direct nucleophilic attack by the oxime moiety on the phosphorus center of the bound nerve agent. Due to a permanently charged pyridinium motif, 2PAM is not thought to cross the blood brain barrier and therefore cannot act directly in the neuronal junctions of the brain. In this study, ADOC, a non-permanently charged, non-oxime molecule initially identified using pesticide-inhibited AChE, was characterized in vitro against nerve agent-inhibited recombinant human AChE. The inhibitory and reactivation potentials of ADOC were determined with native AChE and AChE inhibited with tabun, sarin, soman, cyclosarin, VX, or VR and then compared to those of 2PAM. Several structural analogs of ADOC were used to probe the reactivation mechanism of the molecule. Finally, guinea pigs were used to examine the protective efficacy of the compound after exposure to sarin. The results of both in vitro and in vivo testing will be useful in the design of future small molecule reactivators.
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Affiliation(s)
- C Linn Cadieux
- Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA.
| | - Haoyu Wang
- Chemistry and Biochemistry Department, University of Delaware, Newark, DE 19716, USA
| | - Yuchen Zhang
- Chemistry and Biochemistry Department, University of Delaware, Newark, DE 19716, USA
| | - Jeffrey A Koenig
- Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - Tsung-Ming Shih
- Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - John McDonough
- Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
| | - John Koh
- Chemistry and Biochemistry Department, University of Delaware, Newark, DE 19716, USA
| | - Douglas Cerasoli
- Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD 21010, USA
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15
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Xu MY, Wang P, Sun YJ, Wang HP, Liang YJ, Zhu L, Wu YJ. Redox status in liver of rats following subchronic exposure to the combination of low dose dichlorvos and deltamethrin. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2015; 124:60-65. [PMID: 26453231 DOI: 10.1016/j.pestbp.2015.04.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 04/13/2015] [Accepted: 04/14/2015] [Indexed: 06/05/2023]
Abstract
Organophosphates and pyrethroids are widely used pesticides with prominent toxicity to humans. However, their joint toxicity has not been thoroughly investigated. In this study, we investigated the oxidative damages induced by low dose dichlorvos (DDVP) and deltamethrin (DM), the representative organophosphate and pyrethroid, respectively, and their mixtures in the liver of rats for 90 consecutive days. Two oxidative stress markers, malondialdehyde (MDA) and protein carbonyl (PCO) levels, were measured to reflect the extent of lipid peroxidation and protein oxidation, respectively. DDVP, DM, and their mixtures induced levels of MDA and PCO dose-dependently, although no toxic signs and pathological changes of liver were found in the rats following 90-day exposure. DDVP and DM induced greater increase of MDA than PCO, which indicated that lipids were particularly sensitive to the oxidative damage. We found that DDVP, DM and their mixtures could inhibit the activity of two antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). The effects of DM on SOD activity, lipid peroxidation and protein oxidation were greater than those of DDVP. The combined effect of DDVP and DM was lower than the sum of their individual effects. Thus the interaction between dichlorvos and deltamethrin may be antagonistic on the induction of oxidative stress in rat liver.
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Affiliation(s)
- Ming-Yuan Xu
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichenxi Road, Beijing 100101, China
| | - Pan Wang
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichenxi Road, Beijing 100101, China
| | - Ying-Jian Sun
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichenxi Road, Beijing 100101, China; Department of Veterinary Medicine and Animal Science, Beijing University of Agriculture, Beijing 102206, China
| | - Hui-Ping Wang
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichenxi Road, Beijing 100101, China
| | - Yu-Jie Liang
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichenxi Road, Beijing 100101, China
| | - Li Zhu
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichenxi Road, Beijing 100101, China
| | - Yi-Jun Wu
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichenxi Road, Beijing 100101, China.
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16
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Wilhelm CM, Snider TH, Babin MC, Jett DA, Platoff GE, Yeung DT. A comprehensive evaluation of the efficacy of leading oxime therapies in guinea pigs exposed to organophosphorus chemical warfare agents or pesticides. Toxicol Appl Pharmacol 2014; 281:254-65. [PMID: 25448441 DOI: 10.1016/j.taap.2014.10.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 11/28/2022]
Abstract
The currently fielded pre-hospital therapeutic regimen for the treatment of organophosphorus (OP) poisoning in the United States (U.S.) is the administration of atropine in combination with an oxime antidote (2-PAM Cl) to reactivate inhibited acetylcholinesterase (AChE). Depending on clinical symptoms, an anticonvulsant, e.g., diazepam, may also be administered. Unfortunately, 2-PAM Cl does not offer sufficient protection across the range of OP threat agents, and there is some question as to whether it is the most effective oxime compound available. The objective of the present study is to identify an oxime antidote, under standardized and comparable conditions, that offers protection at the FDA approved human equivalent dose (HED) of 2-PAM Cl against tabun (GA), sarin (GB), soman (GD), cyclosarin (GF), and VX, and the pesticides paraoxon, chlorpyrifos oxon, and phorate oxon. Male Hartley guinea pigs were subcutaneously challenged with a lethal level of OP and treated at approximately 1 min post challenge with atropine followed by equimolar oxime therapy (2-PAM Cl, HI-6 DMS, obidoxime Cl₂, TMB-4, MMB4-DMS, HLö-7 DMS, MINA, and RS194B) or therapeutic-index (TI) level therapy (HI-6 DMS, MMB4-DMS, MINA, and RS194B). Clinical signs of toxicity were observed for 24 h post challenge and blood cholinesterase [AChE and butyrylcholinesterase (BChE)] activity was analyzed utilizing a modified Ellman's method. When the oxime is standardized against the HED of 2-PAM Cl for guinea pigs, the evidence from clinical observations, lethality, quality of life (QOL) scores, and cholinesterase reactivation rates across all OPs indicated that MMB4 DMS and HLö-7 DMS were the two most consistently efficacious oximes.
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Affiliation(s)
| | - Thomas H Snider
- Battelle, 505 King Avenue, JM-7, Columbus, OH 43201-2693, USA.
| | - Michael C Babin
- Battelle, 505 King Avenue, JM-7, Columbus, OH 43201-2693, USA.
| | - David A Jett
- National Institutes of Health/National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA.
| | - Gennady E Platoff
- National Institutes of Health/National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA.
| | - David T Yeung
- National Institutes of Health/National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA.
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17
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Effectiveness of a substituted β-cyclodextrin to prevent cyclosarin toxicity in vivo. Toxicol Lett 2014; 226:222-7. [DOI: 10.1016/j.toxlet.2014.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/10/2014] [Accepted: 02/11/2014] [Indexed: 11/15/2022]
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18
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Hong SP, Gibbs ST, Kobs DJ, Osheroff MR, Johnson JD, Burback BL. Pharmacokinetics of MMB4 DMS in rats, rabbits, and dogs following a single IV administration. Int J Toxicol 2014; 32:30S-7S. [PMID: 23929447 DOI: 10.1177/1091581813488954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Organophosphorus (OP) nerve agents pose tremendous threats to both military and civilian populations. The substance 1,1'-methylenebis[4-[(hydroxyimino)methyl]-pyridinium] (MMB4) is being developed as a replacement for the currently fielded 2-pyridine aldoxime, or pralidoxime (2-PAM) as a treatment for OP nerve agent-induced toxicity. The present study characterized pharmacokinetic (PK) profiles of MMB4 in male and female Sprague-Dawley rats, New Zealand White rabbits, and beagle dogs given a single intravenous (IV) administration of MMB4 dimethanesulfonate (DMS) at 55, 25, and 15 mg/kg dose, respectively. The plasma MMB4 concentration versus time profiles were biphasic for all species tested and fit a 2-compartment model with first-order elimination. There were no overt sex-related differences in the calculated PK parameters. For the rat, rabbit, and dog, the average systemic exposure parameters predicted Cmax (µg/mL) and AUC∞ (µg·h/mL) were 273 and 71.0, 115 and 48.1, and 87.4 and 39.6; the average volume of distribution (mL/kg) values to the central and peripheral compartments were 207 and 143, 242 and 172, and 198 and 213; and the average elimination half-life (hour) and clearance (mL/h/kg) values were 0.18 and 778, 0.29 and 577, and 0.32 and 430, respectively, when the PK parameters for males and females were combined. The current study revealed a similarity in the volume of distribution to the central compartment for MMB4 among the 3 species tested while demonstrating species-related differences in the elimination half-life and clearance of MMB4.
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Affiliation(s)
- S Peter Hong
- Battelle, 505 King Avenue, Columbus, OH 43201, USA.
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19
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Harvilchuck JA, Hong SP, Richey JS, Osheroff MR, Johnson JD. In vivo acetylcholinesterase reactivation in male guinea pigs and rhesus macaques following cyclosarin exposure and treatment with 1,1'-methylenebis{4-[(hydroxyimino)methyl] pyridinium} dimethanesulfonate. Int J Toxicol 2014; 32:99S-107S. [PMID: 23929454 DOI: 10.1177/1091581813498778] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Acetylcholinesterase (AChE) reactivation studies were conducted in guinea pigs (GPs) and nonhuman primates (NHPs) to determine the 1,1'-methylenebis{4-[(hydroxyimino)methyl] pyridinium} dimethanesulfonate (MMB4 DMS) dose that reactivated at least 20% of blood AChE within 15 minutes following cyclosarin (GF) dosing (used as the criterion for efficacy). Male GPs and male rhesus macaques (NHPs) were pretreated with atropine 15 minutes prior to GF administration (1 × median lethal dose [LD50]) and MMB4 DMS 15 minutes following GF administration. The GP survival was 5 of 8, 8 of 8, 8 of 8, and 6 of 8 for the 0.75, 3.0, 6.0, or 12.0 mg/kg MMB4 DMS treatment groups, respectively. In NHPs, survival was 6 of 6 at 0.5, 1.2, 3.0, or 9.3 mg/kg MMB4 DMS, respectively, 24 hours post-challenge, with the majority of animals noted as clinically normal by 24 hours. Pharmacokinetic/pharmacodynamic modeling revealed that 1.8 mg/kg in GPs or 0.013 mg/kg in NHPs would result in an average 20% reactivation; human equivalent doses were calculated as 0.39 mg/kg (based on GP data) and 0.004 mg/kg (based on NHP data). The model suggested that MMB4 plasma concentrations of 1000 ng/mL and AChE reactivation of 80% would be most effective. Although a 0.5 mg/kg MMB4 DMS dose in NHPs resulted in 100% survival and an average of 78% AChE reactivation, adverse effects associated with GF administration were still observed 24 hours post-challenge (tremors, mydriasis, and weakness were observed in 3 of 6 animals). In comparison, 6 of 6 animals treated with 1.2 mg/kg MMB4 DMS were observed as clinically normal 24 hours post-challenge.
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Affiliation(s)
- Jill A Harvilchuck
- Medical Chemical Defense, Battelle, 505 King Avenue, Columbus, OH 43201, USA.
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20
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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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21
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Hong SP, Gibbs ST, Kobs DJ, Hawk MA, Croutch CR, Osheroff MR, Johnson JD, Burback BL. Comparative Toxicokinetics of MMB4 DMS in Rats, Rabbits, Dogs, and Monkeys Following Single and Repeated Intramuscular Administration. Int J Toxicol 2013; 32:38S-48S. [DOI: 10.1177/1091581813488631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
1,1′-Methylenebis[4-[(hydroxyimino)methyl]-pyridinium] (MMB4) dimethanesulfonate (DMS) is a bisquaternary pyridinium aldoxime that reactivates acetylcholinesterase inhibited by organophosphorus nerve agent. Time courses of MMB4 concentrations in plasma were characterized following 7-day repeated intramuscular (IM) administrations of MMB4 DMS to male and female Sprague-Dawley rats, New Zealand White rabbits, beagle dogs (single dose only), and rhesus monkeys at drug dose levels used in earlier toxicology studies. In general, there were no significant differences in MMB4 toxicokinetic (TK) parameters between males and females for all the species tested in these studies. After a single IM administration to rats, rabbits, dogs, and monkeys, MMB4 DMS was rapidly absorbed, resulting in average Tmax values ranging from 5 to 30 minutes. Although Cmax values did not increase dose proportionally, the overall exposure to MMB4 in these preclinical species, as indicated by area under the curve (AUC) extrapolated to the infinity (AUC∞) values, increased in an approximately dose-proportional manner. The MMB4 DMS was extensively absorbed into the systemic circulation after IM administration as demonstrated by greater than 80% absolute bioavailability values for rats, rabbits, and dogs. Repeated administrations of MMB4 DMS for 7 days did not overtly alter TK parameters for MMB4 in rats, rabbits, and monkeys (150 and 300 mg/kg/d dose groups only). However, Cmax and AUC values decreased in monkeys given 450 and 600 mg/kg IM doses of MMB4 DMS following repeated administrations for 7 days. Based on the TK results obtained from the current study and published investigations, it was found that the apparent volume of distribution and clearance values were similar among various preclinical species, except for the rat.
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22
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Roche BM, Vinci TM, Hawk MA, Hassler CR, Pressburger DT, Osheroff MR, Ritchie GD, Burback BL. MMB4 DMS. Int J Toxicol 2013; 32:49S-58S. [DOI: 10.1177/1091581813488632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The objectives of these studies were to determine the cardiopulmonary effects of a single intramuscular administration of 1,1′-methylenebis[4-[(hydroxyimino)methyl]-pyridinium] dimethanesulfonate (MMB4 DMS) on dogs and on the central nervous system in rats. On days 1, 8, 15, and 22, male and female dogs received either vehicle (water for injection/0.5% benzyl alcohol/methane sulfonic acid) or MMB4 DMS (20, 50, or 100 mg/kg). Pulmonary function was evaluated for the first 5 hours after concurrent dosing with cardiovascular monitoring; then cardiovascular monitoring continued for 72 hours after dosing. Rats were dosed once by intramuscular injection with vehicle (water for injection/0.5% benzyl alcohol/methane sulfonic acid) or MMB4 DMS (60, 170, or 340 mg/kg). In dogs, 100 mg/kg MMB4 DMS resulted in increased blood pressure, slightly increased heart rate, slightly prolonged corrected QT, and moderately increased respiratory rate. There were no toxicological effects of MMB4 DMS on neurobehavioral function in rats administered up to 340 mg/kg MMB4 DMS.
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23
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Harvilchuck JA, Hong SP, Richey JS, Osheroff MR, Johnson JD. Efficacy and Pharmacokinetic/Pharmacodynamic Study of 1,1′-Methylenebis{4-[(hydroxyimino)methyl] pyridinium} Dimethanesulfonate in Guinea Pigs and Rhesus Macaques Exposed to Cyclosarin. Int J Toxicol 2013; 32:108S-17S. [DOI: 10.1177/1091581813498425] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Male Hartley guinea pigs and male rhesus macaques were used to determine an efficacious dose of 1,1′-methylenebis{4-[(hydroxyimino)methyl] pyridinium} dimethanesulfonate (MMB4 DMS) that would result in 80% survival, 24 hours following a single exposure to cyclosarin (GF). The pharmacokinetic/pharmacodynamic relationship between acetylcholinesterase activity and MMB4 plasma concentrations relative to survival was evaluated. Guinea pigs and non-human primates (NHPs) were concurrently administered MMB4 DMS (guinea pigs: 0, 10, 30, or 40 mg/kg, intramuscular [IM] and NHPs: 0.1, 1, 5, 10, or 20 mg/kg, IM), atropine, and diazepam following a 3 × median lethal dose (LD50) GF challenge. Clinical observations were evaluated using a quality-of-life (QOL) scoring system. All GF-exposed animals exhibited typical signs of nerve agent poisoning immediately following challenge. In guinea pigs, 24-hour survival was 0%, 50%, 90%, and 90% for 0, 10, 30, and 40 mg/kg MMB4 DMS groups, respectively. In addition, nearly all animals surviving to 24 hours were clinically normal, with many in the 30 and 40 mg/kg MMB4 DMS dose group observed as normal by 4 hours post-challenge. In NHPs, survival was 100% for all treatment groups, with all animals noted as clinically normal by 48 hours. Following treatment with atropine/MMB4 DMS/diazepam, NHPs exhibited dose- and temporal-related decreases in incidence and duration of the clinical signs of toxicity. The QOL scores improved with increasing MMB4 DMS dose in both species. The estimated ED80s were 25.5 mg/kg MMB4 DMS (human equivalent dose [HED] of 5.5 mg/kg) and ≤0.1 mg/kg (HED of 0.03 mg/kg) in guinea pigs and NHPs, respectively.
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Affiliation(s)
| | - S. Peter Hong
- Drug Metabolism and Pharmacokinetics, Battelle, Columbus, OH, USA
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24
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Sterner TR, Ruark CD, Covington TR, Yu KO, Gearhart JM. A physiologically based pharmacokinetic model for the oxime TMB-4: simulation of rodent and human data. Arch Toxicol 2013; 87:661-80. [PMID: 23314320 DOI: 10.1007/s00204-012-0987-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 11/21/2012] [Indexed: 11/29/2022]
Abstract
Multiple oximes have been synthesized and evaluated for use as countermeasures against chemical warfare nerve agents. The current U.S. military and civilian oxime countermeasure, 2-[(hydroxyimino)methyl]-1-methylpyridin-1-ium chloride (2-PAM), is under consideration for replacement with a more effective acetylcholinesterase reactivator, 1,1'-methylenebis{4-hydroxyiminomethyl}pyridinium dimethanesulfonate (MMB-4). Kinetic data in the scientific literature for MMB-4 are limited; therefore, a physiologically based pharmacokinetic (PBPK) model was developed for a structurally related oxime, 1,1'-trimethylenebis{4-hydroximinomethyl}pyridinium dibromide. Based on a previous model structure for the organophosphate diisopropylfluorophosphate, the model includes key sites of acetylcholinesterase inhibition (brain and diaphragm), as well as fat, kidney, liver, rapidly perfused tissues and slowly perfused tissues. All tissue compartments are diffusion limited. Model parameters were collected from the literature, predicted using quantitative structure-property relationships or, when necessary, fit to available pharmacokinetic data from the literature. The model was parameterized using rat plasma, tissue and urine time course data from intramuscular administration, as well as human blood and urine data from intravenous and intramuscular administration; sensitivity analyses were performed. The PBPK model successfully simulates rat and human data sets and has been evaluated by predicting intravenous mouse and intramuscular human data not used in the development of the model. Monte Carlo analyses were performed to quantify human population kinetic variability in the human evaluation data set. The model identifies potential pharmacokinetic differences between rodents and humans, indicated by differences in model parameters between species. The PBPK model can be used to optimize the dosing regimen to improve oxime therapeutic efficacy in a human population.
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Affiliation(s)
- Teresa R Sterner
- Henry M. Jackson Foundation for the Advancement of Military Medicine, 2729 R Street, Bldg 837, Wright-Patterson AFB, OH 45433-5707, USA.
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25
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Kinetic interactions of a homologous series of bispyridinium monooximes (HGG oximes) with native and phosphonylated human acetylcholinesterase. Toxicol Lett 2012; 212:29-32. [DOI: 10.1016/j.toxlet.2012.04.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 04/23/2012] [Accepted: 04/24/2012] [Indexed: 11/17/2022]
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26
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Kassa J, Zdarova Karasova J, Sepsova V. A comparison of the reactivating efficacy of a novel bispyridinium oxime K203 with currently available oximes in VX agent-poisoned rats. J Enzyme Inhib Med Chem 2012; 28:753-7. [DOI: 10.3109/14756366.2012.681652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jiri Kassa
- Department of Toxicology, Faculty of Military Health Sciences,
Hradec Kralove, Czech Republic
| | - Jana Zdarova Karasova
- Department of Public Health, Faculty of Military Health Sciences,
Hradec Kralove, Czech Republic
| | - Vendula Sepsova
- Department of Toxicology, Faculty of Military Health Sciences,
Hradec Kralove, Czech Republic
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27
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dos Santos AA, dos Santos DB, Ribeiro RP, Colle D, Peres KC, Hermes J, Barbosa AM, Dafré AL, de Bem AF, Kuca K, Farina M. Effects of K074 and pralidoxime on antioxidant and acetylcholinesterase response in malathion-poisoned mice. Neurotoxicology 2011; 32:888-95. [DOI: 10.1016/j.neuro.2011.05.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 04/20/2011] [Accepted: 05/19/2011] [Indexed: 12/21/2022]
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28
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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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29
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Lundy PM, Hamilton MG, Sawyer TW, Mikler J. Comparative protective effects of HI-6 and MMB-4 against organophosphorous nerve agent poisoning. Toxicology 2011; 285:90-6. [DOI: 10.1016/j.tox.2011.04.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 04/04/2011] [Accepted: 04/08/2011] [Indexed: 10/18/2022]
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30
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Inhibition of blood and tissue cholinesterases by soman in guinea pigs in vivo. J Appl Biomed 2011. [DOI: 10.2478/v10136-009-0030-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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31
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Fišar Z, Hroudová J, Korábečný J, Musílek K, Kuča K. In vitro effects of acetylcholinesterase reactivators on monoamine oxidase activity. Toxicol Lett 2011; 201:176-80. [DOI: 10.1016/j.toxlet.2010.12.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 12/21/2010] [Accepted: 12/23/2010] [Indexed: 01/10/2023]
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32
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Worek F, Wille T, Aurbek N, Eyer P, Thiermann H. Reactivation of organophosphate-inhibited human, Cynomolgus monkey, swine and guinea pig acetylcholinesterase by MMB-4: A modified kinetic approach. Toxicol Appl Pharmacol 2010; 249:231-7. [DOI: 10.1016/j.taap.2010.09.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 09/20/2010] [Accepted: 09/23/2010] [Indexed: 11/30/2022]
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33
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Shih TM, Guarisco JA, Myers TM, Kan RK, McDonough JH. The oxime pro-2-PAM provides minimal protection against the CNS effects of the nerve agents sarin, cyclosarin, and VX in guinea pigs. Toxicol Mech Methods 2010; 21:53-62. [DOI: 10.3109/15376516.2010.529190] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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O’Donnell JC, Acon-Chen C, McDonough JH, Shih TM. Comparison of extracellular striatal acetylcholine and brain seizure activity following acute exposure to the nerve agents cyclosarin and tabun in freely moving guinea pigs. Toxicol Mech Methods 2010; 20:600-8. [DOI: 10.3109/15376516.2010.521208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Skovira JW, O’Donnell JC, Koplovitz I, Kan RK, McDonough JH, Shih TM. Reactivation of brain acetylcholinesterase by monoisonitrosoacetone increases the therapeutic efficacy against nerve agents in guinea pigs. Chem Biol Interact 2010; 187:318-24. [DOI: 10.1016/j.cbi.2010.03.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 02/15/2010] [Accepted: 03/05/2010] [Indexed: 10/19/2022]
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