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Skomal AE, Zhang J, Yang K, Yen J, Tu X, Suarez-Torres J, Lopez-Paredes D, Calafat AM, Ospina M, Martinez D, Suarez-Lopez JR. Concurrent urinary organophosphate metabolites and acetylcholinesterase activity in Ecuadorian adolescents. ENVIRONMENTAL RESEARCH 2022; 207:112163. [PMID: 34627797 PMCID: PMC9138777 DOI: 10.1016/j.envres.2021.112163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Organophosphates are insecticides that inhibit the enzymatic activity of acetylcholinesterase (AChE). Because of this, AChE is considered a physiological marker of organophosphate exposure in agricultural settings. However, limited research exists on the associations between urinary organophosphate metabolites and AChE activity in children. METHODS This study included 526 participants from 2 exams (April and July-October 2016) of ages 12-17 years living in agricultural communities in Ecuador. AChE activity was measured at both examinations, and organophosphate metabolites, including para-nitrophenol (PNP), 3,5,6-trichloro-2-pyridinol (TCPy), and malathion dicarboxylic acid (MDA) were measured in urine collected in July-October. We used generalized estimating equation generalized linear model (GEEGLM), adjusting for hemoglobin, creatinine, and other demographic and anthropometric covariates, to estimate associations of urinary metabolite concentrations with AChE activity (July-October) and AChE% change between April and July-October. RESULTS The mean (SD) of AChE and AChE% change (April vs July-October) were 3.67 U/mL (0.54) and -2.5% (15.4%), respectively. AChE activity was inversely associated with PNP concentration, whereas AChE% change was inversely associated with PNP and MDA. There was evidence of a threshold: difference was only significant above the 80th percentile of PNP concentration (AChE difference per SD increase of metabolite = -0.12 U/mL [95%CI: 0.20, -0.04]). Likewise, associations with AChE% change were significant only above the 80th percentile of TCPy (AChE % change per SD increase of metabolite = -1.38% [95%CI: 2.43%, -0.32%]) and PNP -2.47% [95%CI: 4.45%, -0.50%]). PNP concentration at ≥80th percentile was associated with elevated ORs for low AChE activity of 2.9 (95% CI: 1.5, 5.7) and for AChE inhibition of ≤ -10% of 3.7 (95% CI: 1.4, 9.8). CONCLUSIONS Urinary organophosphate metabolites, including PNP, TCPy and MDA, particularly at concentrations above the 80th percentile, were associated with lower AChE activity among adolescents. These findings bring attention to the value of using multiple constructs of pesticide exposure in epidemiologic studies.
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Affiliation(s)
- Ana E Skomal
- School of Medicine, University of California-San Diego, La Jolla, CA, USA
| | - Jasen Zhang
- Herbert Wertheim School of Public Health, University of California-San Diego, La Jolla, CA, USA
| | - Kun Yang
- School of Medicine, University of California-San Diego, La Jolla, CA, USA
| | - Jessica Yen
- School of Medicine, University of California-San Diego, La Jolla, CA, USA
| | - Xin Tu
- School of Medicine, University of California-San Diego, La Jolla, CA, USA
| | | | | | - Antonia M Calafat
- National Center for Environmental Health, Division of Laboratory Sciences of the Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Maria Ospina
- National Center for Environmental Health, Division of Laboratory Sciences of the Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Jose R Suarez-Lopez
- Herbert Wertheim School of Public Health, University of California-San Diego, La Jolla, CA, USA.
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Lenina OA, Zueva IV, Zobov VV, Semenov VE, Masson P, Petrov KA. Slow-binding reversible inhibitor of acetylcholinesterase with long-lasting action for prophylaxis of organophosphate poisoning. Sci Rep 2020; 10:16611. [PMID: 33024231 PMCID: PMC7538863 DOI: 10.1038/s41598-020-73822-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 09/22/2020] [Indexed: 12/02/2022] Open
Abstract
Organophosphorus (OP) compounds represent a serious health hazard worldwide. The dominant mechanism of their action results from covalent inhibition of acetylcholinesterase (AChE). Standard therapy of acute OP poisoning is partially effective. However, prophylactic administration of reversible or pseudo-irreversible AChE inhibitors before OP exposure increases the efficiency of standard therapy. The purpose of the study was to test the duration of the protective effect of a slow-binding reversible AChE inhibitor (C547) in a mouse model against acute exposure to paraoxon (POX). It was shown that the rate of inhibition of AChE by POX in vitro after pre-inhibition with C547 was several times lower than without C547. Ex vivo pre-incubation of mouse diaphragm with C547 significantly prevented the POX-induced muscle weakness. Then it was shown that pre-treatment of mice with C547 at the dose of 0.01 mg/kg significantly increased survival after poisoning by 2xLD50 POX. The duration of the pre-treatment was effective up to 96 h, whereas currently used drug for pre-exposure treatment, pyridostigmine at a dose of 0.15 mg/kg was effective less than 24 h. Thus, long-lasting slow-binding reversible AChE inhibitors can be considered as new potential drugs to increase the duration of pre-exposure treatment of OP poisoning.
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Affiliation(s)
- Oksana A Lenina
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, Russian Federation, 420088
| | - Irina V Zueva
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, Russian Federation, 420088
| | - Vladimir V Zobov
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, Russian Federation, 420088
- Kazan Federal University, 18 Kremlyovskaya str, Kazan, Russia, 420008
| | - Vyacheslav E Semenov
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, Russian Federation, 420088
| | - Patrick Masson
- Kazan Federal University, 18 Kremlyovskaya str, Kazan, Russia, 420008
| | - Konstantin A Petrov
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan, Russian Federation, 420088.
- Kazan Federal University, 18 Kremlyovskaya str, Kazan, Russia, 420008.
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Lorke DE, Nurulain SM, Hasan MY, Kuča K, Petroianu GA. Oximes as pretreatment before acute exposure to paraoxon. J Appl Toxicol 2019; 39:1506-1515. [PMID: 31264735 DOI: 10.1002/jat.3835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 05/15/2019] [Accepted: 05/16/2019] [Indexed: 11/11/2022]
Abstract
Organophosphates, useful agents as pesticides, also represent a serious danger due to their high acute toxicity. There is indication that oximes, when administered before organophosphate exposure, can protect from these toxic effects. We have tested at equitoxic dosage (25% of LD01 ) the prophylactic efficacy of five experimental (K-48, K-53, K-74, K-75, K-203) and two established oximes (pralidoxime and obidoxime) to protect from mortality induced by the organophosphate paraoxon. Mortalities were quantified by Cox analysis and compared with those observed after pretreatment with a strong acetylcholinesterase inhibitor (10-methylacridine) and after the FDA-approved pretreatment compound pyridostigmine. All nine tested substances statistically significantly reduced paraoxon-induced mortality. Best protection was conferred by the experimental oxime K-48, reducing the relative risk of death (RR) to 0.10, which was statistically significantly superior to pyridostigmine (RR = 0.31). The other oximes reduced the RR to 0.13 (obidoxime), 0.20 (K-203), 0.21 (K-74), 0.24 (K-75) and 0.26 (pralidoxime), which were significantly more efficacious than 10-methylacridine (RR = 0.65). These data support the hypothesis that protective efficacy is not primarily due to cholinesterase inhibition and indicate that the tested experimental oximes may be considered promising alternatives to the established pretreatment compound pyridostigmine.
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Affiliation(s)
- Dietrich E Lorke
- Department of Cellular Biology & Pharmacology, Herbert Wertheim College of Medicine, University Park GL 495 D, Florida International University, Miami, Florida.,College of Medicine and Health Sciences, Department of Anatomy and Cellular Biology, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Syed M Nurulain
- Department of Bio Science, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Mohamed Y Hasan
- Department of Pharmacology & Therapeutics, College of Medicine and Health Sciences, UAE University, United Arab Emirates
| | - Kamil Kuča
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| | - Georg A Petroianu
- Department of Cellular Biology & Pharmacology, Herbert Wertheim College of Medicine, University Park GL 495 D, Florida International University, Miami, Florida
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Kobrlova T, Korabecny J, Soukup O. Current approaches to enhancing oxime reactivator delivery into the brain. Toxicology 2019; 423:75-83. [PMID: 31112674 DOI: 10.1016/j.tox.2019.05.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/17/2019] [Accepted: 05/13/2019] [Indexed: 01/21/2023]
Abstract
The misuse of organophosphate compounds still represents a current threat worldwide. Treatment of poisoning with organophosphates (OPs) remains unsatisfactorily resolved despite the extensive investment in research in academia. There are no universal, effective and centrally-active acetylcholinesterase (AChE) reactivators to countermeasure OP intoxication. One major obstacle is to overcome the blood-brain barrier (BBB). The central compartment is readily accessible by the OPs which are lipophilic bullets that can easily cross the BBB, whereas first-line therapeutics, namely oxime-based AChE reactivators and atropine, do not cross or do so rather slowly. The limitation of oxime-based AChE reactivators can be ascribed to their chemical nature, bearing a positive charge which is essential either for their AChE affinity or their reactivating potency. The aim of this article is to review the methods for targeting the brain by oxime reactivators that have been developed so far. Approaches using prodrugs, lipophilicity enhancement, or sugar-based oximes have been rather unsuccessful. However, other strategies have been more promising, such as the use of nanoparticles or co-administration of the reactivator with efflux transporter inhibitors. Encouraging results have also been associated with intranasal delivery, but research in this field is still at the beginning. Further research of auspicious approaches is inevitable.
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Affiliation(s)
- Tereza Kobrlova
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01, Hradec Kralove, Czech Republic; Biomedical Research Centre, University Hospital, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.
| | - Jan Korabecny
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01, Hradec Kralove, Czech Republic; Biomedical Research Centre, University Hospital, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.
| | - Ondrej Soukup
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 500 01, Hradec Kralove, Czech Republic; Biomedical Research Centre, University Hospital, Sokolska 581, 500 05, Hradec Kralove, Czech Republic.
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5
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Efficacy of antidotes and their combinations in the treatment of acute carbamate poisoning in rats. Toxicology 2018; 408:113-124. [DOI: 10.1016/j.tox.2018.08.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/22/2018] [Accepted: 08/29/2018] [Indexed: 11/23/2022]
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Lorke DE, Petroianu GA. Reversible cholinesterase inhibitors as pretreatment for exposure to organophosphates. A review. J Appl Toxicol 2018; 39:101-116. [PMID: 30027640 DOI: 10.1002/jat.3662] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/06/2018] [Indexed: 01/04/2023]
Abstract
Organophosphorus compounds (OPCs), inhibitors of acetylcholinesterase (AChE), are useful agents as pesticides, but also represent a serious health hazard. Standard therapy with atropine and established oxime-type enzyme reactivators (pralidoxime, obidoxime) is unsatisfactory. Better therapeutic results are obtained, when reversible AChE inhibitors are administered before OPC exposure. This review summarizes the history of such a pretreatment approach and sums up a set of experiments undertaken in search of compounds that are efficacious when given before a broad range of OPCs. The prophylactic efficacy of 10 known AChE inhibitors, either already used clinically for different indications (physostigmine, pyridostigmine, ranitidine, tiapride, tacrine, amiloride, metoclopramide, methylene blue) or developed for possible therapeutic use in the future (7-methoxytacrine, K-27) was compared, when administered before exposure to six chemically diverse OPCs in the same experimental setting: ethyl-paraoxon, methyl-paraoxon, diisopropylfluorophosphate, terbufos sulfone, azinphos-methyl and dicrotophos. The experimental oxime K-27 was the most efficacious compound, affording best protection, when administered before terbufos sulfone, azinphos-methyl and dicrotophos, second best before ethyl- and methyl-paraoxon exposure and third best before diisopropylfluorophosphate administration. This ranking was similar to that of physostigmine, which was superior to the Food and Drug Administration-approved pretreatment for soman with pyridostigmine. Tiapride, amiloride, metoclopramide, methylene blue and 7-methoxytacrine did not achieve protection. No correlation was observed between the IC50 of the reversible AChE inhibitors and their protective efficacy. These studies indicate that K-27 can be considered a very promising broad-spectrum prophylactic agent in case of imminent organophosphate exposure, which may be related to its AChE reactivating activity rather than its AChE inhibition.
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Affiliation(s)
- Dietrich E Lorke
- Department of Cellular Biology & Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Georg A Petroianu
- Department of Cellular Biology & Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
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7
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Worek F, Thiermann H, Wille T. The oximes HI-6 and MMB-4 fail to reactivate soman-inhibited human and guinea pig AChE: A kinetic in vitro study. Toxicol Lett 2017; 293:216-221. [PMID: 28993240 DOI: 10.1016/j.toxlet.2017.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 09/26/2017] [Accepted: 10/04/2017] [Indexed: 11/18/2022]
Abstract
Acetylcholinesterase (AChE) inhibited by the organophosphorus nerve (OP) agent soman underlies a spontaneous and extremely rapid dealkylation ("aging") reaction which prevents reactivation by oximes. However, in vivo studies in various, soman poisoned animal species showed a therapeutic effect of oximes, with the exact mechanism of this effect remaining still unclear. In order to get more insight and a basis for the extrapolation of animal data to humans, we applied a dynamic in vitro model with continuous online determination of AChE activity. This model allows to simulate the in vivo toxico- and pharmacokinetics between human and guinea pig AChE with soman and the oximes HI-6 and MMB-4 in order to unravel the species dependent kinetic interactions. It turned out that only HI-6 was able to slow down the ongoing inhibition of human AChE by soman without preventing final complete inhibition of the enzyme. Continuous perfusion of AChE with soman and simultaneous or delayed (8, 15 or 40min) oxime perfusion did not result in a relevant reactivation of AChE (less than 2%). In conclusion, the results of the present study indicate a negligible reactivation of soman-inhibited AChE by oximes at conditions simulating the in vivo poisoning by soman. The observed therapeutic effect of oximes in soman poisoned animals in vivo must be attributed to alternative mechanisms which may not be relevant in humans.
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Affiliation(s)
- Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany.
| | - Horst Thiermann
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Timo Wille
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
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8
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Masson P, Nachon F. Cholinesterase reactivators and bioscavengers for pre- and post-exposure treatments of organophosphorus poisoning. J Neurochem 2017; 142 Suppl 2:26-40. [PMID: 28542985 DOI: 10.1111/jnc.14026] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/02/2017] [Accepted: 03/10/2017] [Indexed: 12/11/2022]
Abstract
Organophosphorus agents (OPs) irreversibly inhibit acetylcholinesterase (AChE) causing a major cholinergic syndrome. The medical counter-measures of OP poisoning have not evolved for the last 30 years with carbamates for pretreatment, pyridinium oximes-based AChE reactivators, antimuscarinic drugs and neuroprotective benzodiazepines for post-exposure treatment. These drugs ensure protection of peripheral nervous system and mitigate acute effects of OP lethal doses. However, they have significant limitations. Pyridostigmine and oximes do not protect/reactivate central AChE. Oximes poorly reactivate AChE inhibited by phosphoramidates. In addition, current neuroprotectants do not protect the central nervous system shortly after the onset of seizures when brain damage becomes irreversible. New therapeutic approaches for pre- and post-exposure treatments involve detoxification of OP molecules before they reach their molecular targets by administrating catalytic bioscavengers, among them phosphotriesterases are the most promising. Novel generation of broad spectrum reactivators are designed for crossing the blood-brain barrier and reactivate central AChE. This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms.
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Affiliation(s)
- Patrick Masson
- Neuropharmacology Laboratory, Kazan Federal University, Kazan, Russia
| | - Florian Nachon
- Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, Cédex, France
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9
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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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10
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Bierwisch A, Wille T, Thiermann H, Worek F. Kinetic analysis of interactions of amodiaquine with human cholinesterases and organophosphorus compounds. Toxicol Lett 2016; 246:49-56. [PMID: 26851641 DOI: 10.1016/j.toxlet.2016.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 01/30/2016] [Accepted: 02/02/2016] [Indexed: 10/22/2022]
Abstract
Standard therapy of poisoning by organophosphorus compounds (OP) is a combined administration of an anti-muscarinic drug (e.g. atropine) and an oxime as reactivator of inhibited acetylcholinesterase (AChE). Limited efficacy of clinically used oximes against a variety of OPs was shown in numerous studies, calling for research on novel reactivators of OP-inhibited AChE. Recently, reactivation of OP-inhibited AChE by the antimalarial drug amodiaquine was reported. In the present study, amodiaquine and its interactions with human cholinesterases in presence or absence of OP nerve agents was investigated in vitro. Thereby, reversible inhibition of human cholinesterases by amodiaquine (AChE ≫ BChE) was observed. Additionally, a mixed competitive-non-competitive inhibition type of amodiaquine with human AChE was determined. Slow and partial reactivation of sarin-, cyclosarin- and VX-inhibited cholinesterases by amodiaquine was recorded, amodiaquine failed to reactivate tabun-inhibited human cholinesterases. Amodiaquine, being a potent, reversible AChE inhibitor, was tested for its potential benefit as a pretreatment to prevent complete irreversible AChE inhibition by the nerve agent soman. Hereby, amodiaquine failed to prevent phosphonylation and resulted only in a slight increase of AChE activity after removal of amodiaquine and soman. At present the molecular mechanism of amodiaquine-induced reactivation of OP-inhibited AChE is not known, nevertheless amodiaquine could be considered as a template for the design of more potent non-oxime reactivators.
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Affiliation(s)
- Anne Bierwisch
- Institut für Pharmakologie und Toxikologie der Bundeswehr, Neuherbergstraße 11, 80937 München, Germany
| | - Timo Wille
- Institut für Pharmakologie und Toxikologie der Bundeswehr, Neuherbergstraße 11, 80937 München, Germany
| | - Horst Thiermann
- Institut für Pharmakologie und Toxikologie der Bundeswehr, Neuherbergstraße 11, 80937 München, Germany
| | - Franz Worek
- Institut für Pharmakologie und Toxikologie der Bundeswehr, Neuherbergstraße 11, 80937 München, Germany.
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Jang YJ, Kim K, Tsay OG, Atwood DA, Churchill DG. Update 1 of: Destruction and Detection of Chemical Warfare Agents. Chem Rev 2015; 115:PR1-76. [DOI: 10.1021/acs.chemrev.5b00402] [Citation(s) in RCA: 249] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Yoon Jeong Jang
- Molecular Logic Gate Laboratory, Department of Chemistry, KAIST, Daejeon, 305-701, Republic of Korea
| | - Kibong Kim
- Molecular Logic Gate Laboratory, Department of Chemistry, KAIST, Daejeon, 305-701, Republic of Korea
| | - Olga G. Tsay
- Molecular Logic Gate Laboratory, Department of Chemistry, KAIST, Daejeon, 305-701, Republic of Korea
| | - David A. Atwood
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, United States
| | - David G. Churchill
- Molecular Logic Gate Laboratory, Department of Chemistry, KAIST, Daejeon, 305-701, Republic of Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), 373-1 Guseong-dong, Yuseong-gu, Daejeon, 305−701, Republic of Korea
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12
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Worek F, Horn G, Wille T, Thiermann H. Adaptation of a dynamic in vitro model with real-time determination of butyrylcholinesterase activity in the presence of cyclosarin and an oxime. Toxicol In Vitro 2015; 29:162-7. [DOI: 10.1016/j.tiv.2014.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 09/29/2014] [Accepted: 10/06/2014] [Indexed: 02/03/2023]
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Jeon J, Kretschmann A, Escher BI, Hollender J. Characterization of acetylcholinesterase inhibition and energy allocation in Daphnia magna exposed to carbaryl. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2013; 98:28-35. [PMID: 24139064 DOI: 10.1016/j.ecoenv.2013.09.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 09/21/2013] [Accepted: 09/25/2013] [Indexed: 06/02/2023]
Abstract
The inhibition of acetylcholinesterase (AChE) activity and energy allocation in the freshwater organism Daphnia magna exposed to carbaryl and potential recovery from the effects was examined. The binding of carbaryl-AChE was characterized through in vitro assays. To evaluate the recovery from inhibition and the alteration in energy budget, in vivo exposure and recovery regime tests were conducted. In comparison to diazoxon, the active metabolite of the insecticide diazinon, the stability of enzyme-carbaryl complex was fifteen times lower and the reactivity toward the active site was two times lower, resulting in approximately 30 times lower overall inhibition rate than for diazoxon. The in vitro reactivation rate constant of the inhibited enzyme and the in vivo recovery rate constant of AChE activity were 1.9 h⁻¹ and 0.12 h⁻¹ for carbaryl, respectively, which are much higher than the corresponding rate constants for diazoxon. The lower AChE inhibition and greater reactivation/recovery rates are in accordance with the lower toxicity of carbaryl compared to diazinon. Carbaryl exposure also altered the profile of the energy reserve: the decrease in lipid and glycogen and the increase in protein content resulted in the reduction of the total energy budget by about 45 mJ/g(ww). This corresponds to 26 percent of the available energy, which might allocate for external stressors. The mechanistic model of AChE inhibition is helpful to get an insight into (eco-)toxicological effects of AChE inhibitors on freshwater crustaceans under environmentally realistic conditions.
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Affiliation(s)
- Junho Jeon
- Swiss Federal Institute of Aquatic Science and Technology (Eewag), Überlandstrasse 133, 8600 Dübendorf, Switzerland.
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Wilson BW, Rusli FJ, Yan Tam MK, DePeters E, Henderson JD. Carbamate protection of AChE against inhibition by agricultural chemicals. J Biochem Mol Toxicol 2012; 26:506-9. [PMID: 23169765 DOI: 10.1002/jbt.21456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 10/02/2012] [Accepted: 10/13/2012] [Indexed: 10/27/2022]
Abstract
The carbamate pyridostigmine bromide has been used as a pretreatment to protect individuals from the nerve agent soman. Previous research showed that pyridostigmine significantly protected human muscle acetylcholinesterase in vitro from soman and bovine red blood cell acetylcholinesterase from some organophosphorous pesticides. Research presented here demonstrates that pretreatment with other carbamates also protects acetylcholinesterase from inhibition by the pesticides chlorpyrifos-oxon and diazinon-oxon, but not from malaoxon.
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Affiliation(s)
- Barry W Wilson
- Animal Science Department, University of California-Davis, Davis, CA 95616, USA.
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15
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Wang Y, Wei Y, Oguntayo S, Doctor BP, Nambiar MP. A combination of [+] and [-]-Huperzine A improves protection against soman toxicity compared to [+]-Huperzine A in guinea pigs. Chem Biol Interact 2012; 203:120-4. [PMID: 23123250 DOI: 10.1016/j.cbi.2012.10.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/10/2012] [Accepted: 10/15/2012] [Indexed: 01/01/2023]
Abstract
The neuropathologic mechanisms after exposure to lethal doses of nerve agent are complex and involve multiple biochemical pathways. Effective treatment requires drugs that can simultaneously protect by reversible binding to the acetylcholinesterase (AChE) and blocking cascades of seizure related brain damage, inflammation, neuronal degeneration as well as promoting induction of neuroregeneration. [-]-Huperzine A ([-]-Hup A), is a naturally occurring potent reversible AChE inhibitor that penetrates the blood-brain barrier. It also has several neuroprotective effects including modification of beta-amyloid peptide, reduction of oxidative stress, anti-inflammatory, anti-apoptotic and induction and regulation of nerve growth factor. Toxicities at higher doses restrict the neuroporotective ability of [-]-Hup A for treatment. The synthetic stereoisomer, [+]-Hup A, is less toxic due to poor AChE inhibition and is suitable for both pre-/post-exposure treatments of nerve agent toxicity. [+]-Hup A block the N-methyl-D-aspartate (NMDA)-induced seizure in rats, reduce excitatory amino acid induced neurotoxicity and also prevent soman induced toxicity with minimum performance decrement. Unique combinations of two stereo-isomers of Hup A may provide an excellent pre/post-treatment drug for the nerve agent induced seizure/status epilepticus. We investigated a combination of [+]-Hup A with a small dose of [-]-Hup A ([+] and [-]-Hup A) against soman toxicity. Our data showed that pretreatment with a combination [+] and [-]-Hup A significantly increased the survival rate and reduced behavioral abnormalities after exposure to 1.2 × LD(50) soman compared to [+]-Hup A in guinea pigs. In addition, [+] and [-]-Hup A pretreatment inhibited the development of high power of EEG better than [+]-Hup A pretreatment alone. These data suggest that a combination of [+] and [-]-Hup A offers better protection than [+]-Hup A and serves as a potent medical countermeasure against lethal dose nerve agent toxicity in guinea pigs.
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Affiliation(s)
- Ying Wang
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
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Schultz MK, Wright LKM, Stone MF, Schwartz JE, Kelley NR, Moffett MC, Lee RB, Lumley LA. The anticholinergic and antiglutamatergic drug caramiphen reduces seizure duration in soman-exposed rats: synergism with the benzodiazepine diazepam. Toxicol Appl Pharmacol 2012; 259:376-86. [PMID: 22310180 DOI: 10.1016/j.taap.2012.01.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 01/20/2012] [Accepted: 01/22/2012] [Indexed: 11/26/2022]
Abstract
Therapy of seizure activity following exposure to the nerve agent soman (GD) includes treatment with the anticonvulsant diazepam (DZP), an allosteric modulator of γ-aminobutyric acid A (GABA(A)) receptors. However, seizure activity itself causes the endocytosis of GABA(A) receptors and diminishes the inhibitory effects of GABA, thereby reducing the efficacy of DZP. Treatment with an N-methyl-d-aspartic acid (NMDA) receptor antagonist prevents this reduction in GABAergic inhibition. We examined the efficacy of the NMDA receptor antagonist caramiphen edisylate (CED; 20mg/kg, im) and DZP (10mg/kg, sc), administered both separately and in combination, at 10, 20 or 30min following seizure onset for attenuation of the deleterious effects associated with GD exposure (1.2 LD(50); 132μg/kg, sc) in rats. Outcomes evaluated were seizure duration, neuropathology, acetylcholinesterase (AChE) activity, body weight, and temperature. We also examined the use of the reversible AChE inhibitor physostigmine (PHY; 0.2mg/kg, im) as a therapy for GD exposure. We found that the combination of CED and DZP yielded a synergistic effect, shortening seizure durations and reducing neuropathology compared to DZP alone, when treatment was delayed 20-30min after seizure onset. PHY reduced the number of animals that developed seizures, protected a fraction of AChE from GD inhibition, and attenuated post-exposure body weight and temperature loss independent of CED and/or DZP treatment. We conclude that: 1) CED and DZP treatment offers considerable protection against the effects of GD and 2) PHY is a potential therapeutic option following GD exposure, albeit with a limited window of opportunity.
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Affiliation(s)
- M K Schultz
- US Army Medical Research Institute of Chemical Defense, 3100 Ricketts Point Road, Aberdeen Proving Ground, MD 21010-5400, USA
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Herkert N, Schulz S, Wille T, Thiermann H, Hatz R, Worek F. Pre- and post-treatment effect of physostigmine on soman-inhibited human erythrocyte and muscle acetylcholinesterase in vitro. Toxicol Appl Pharmacol 2011; 253:7-13. [DOI: 10.1016/j.taap.2011.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 03/04/2011] [Accepted: 03/06/2011] [Indexed: 11/16/2022]
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Masson P. Evolution of and perspectives on therapeutic approaches to nerve agent poisoning. Toxicol Lett 2011; 206:5-13. [PMID: 21524695 DOI: 10.1016/j.toxlet.2011.04.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 04/08/2011] [Indexed: 01/18/2023]
Abstract
After more than 70 years of considerable efforts, research on medical defense against nerve agents has come to a standstill. Major progress in medical countermeasures was achieved between the 50s and 70s with the development of anticholinergic drugs and carbamate-based pretreatment, the introduction of pyridinium oximes as antidotes, and benzodiazepines in emergency treatments. These drugs ensure good protection of the peripheral nervous system and mitigate the acute effects of exposure to lethal doses of nerve agents. However, pyridostigmine and cholinesterase reactivators currently used in the armed forces do not protect/reactivate central acetylcholinesterases. Moreover, other drugs used are not sufficiently effective in protecting the central nervous system against seizures, irreversible brain damages and long-term sequelae of nerve agent poisoning.New developments of medical counter-measures focus on: (a) detoxification of organophosphorus molecules before they react with acetylcholinesterase and other physiological targets by administration of stoichiometric or catalytic scavengers; (b) protection and reactivation of central acetylcholinesterases, and (c) improvement of neuroprotection following delayed therapy.Future developments will aim at treatment of acute and long-term effects of low level exposure to nerve agents, research on alternative routes for optimizing drug delivery, and therapies. Though gene therapy for in situ generation of bioscavengers, and cell therapy based on neural progenitor engraftment for neuronal regeneration have been successfully explored, more studies are needed before practical medical applications can be made of these new approaches.
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Affiliation(s)
- Patrick Masson
- IRBA-CRSSA, Toxicology Dept., 38702 La Tronche Cedex, France.
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Herkert NM, Thiermann H, Worek F. In vitro kinetic interactions of pyridostigmine, physostigmine and soman with erythrocyte and muscle acetylcholinesterase from different species. Toxicol Lett 2011; 206:41-6. [PMID: 21414391 DOI: 10.1016/j.toxlet.2011.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 03/02/2011] [Indexed: 10/18/2022]
Abstract
The low effectiveness of atropine and oxime treatment in soman poisoning may be enhanced by carbamates pre-treatment. For ethical reasons medical countermeasures can only be tested in animal models despite the fact of substantial species differences. With this kinetic in vitro study the interactions between pyridostigmine, physostigmine and soman with human, Rhesus monkey, swine and guinea pig erythrocyte AChE were investigated. In addition, the effect of the carbamates on the residual activity and enzyme recovery after soman inhibition was examined with erythrocyte and intercostal muscle AChE from these species with a dynamic in vitro model with real-time determination of AChE activity. Only small to moderate species differences of the inhibition and decarbamylation kinetics were recorded. It was possible to show that with erythrocyte and muscle AChE a similar level of protection by carbamates and reactivation after discontinuation of the carbamates and soman could be observed. Thus, these data indicate that carbamate pre-treatment is expected to protect a critical level of muscle AChE and confirm the presumption that erythrocyte AChE may serve as a surrogate for synaptic AChE. Hence, these and previous data fortify the notion that erythrocyte AChE is a proper tool for in vitro kinetic studies as well as for therapeutic monitoring in experimental and clinical studies.
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Affiliation(s)
- N M Herkert
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937 Munich, Germany
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Malkova L, Kozikowski AP, Gale K. The effects of huperzine A and IDRA 21 on visual recognition memory in young macaques. Neuropharmacology 2010; 60:1262-8. [PMID: 21185313 DOI: 10.1016/j.neuropharm.2010.12.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 11/29/2010] [Accepted: 12/15/2010] [Indexed: 11/26/2022]
Abstract
Nootropic agents or cognitive enhancers are purported to improve mental functions such as cognition, memory, or attention. The aim of our study was to determine the effects of two possible cognitive enhancers, huperzine A and IDRA 21, in normal young adult monkeys performing a visual memory task of varying degrees of difficulty. Huperzine A is a reversible acetylcholinesterase (AChE) inhibitor, its administration results in regionally specific increases in acetylcholine levels in the brain. In human clinical trials, Huperzine A resulted in cognitive improvement in patients with mild to moderate form of Alzheimer's disease (AD) showing its potential as a palliative agent in the treatment of AD. IDRA 21 is a positive allosteric modulator of glutamate AMPA receptors. It increases excitatory synaptic strength by attenuating rapid desensitization of AMPA receptors and may thus have beneficial therapeutic effects to ameliorate memory deficits in patients with cognitive impairments, including AD. The present study evaluated the effects of the two drugs in normal, intact, young adult monkeys to determine whether they can result in cognitive enhancement in a system that is presumably functioning optimally. Six young pigtail macaques (Macaca nemestrina) were trained on delayed non-matching-to-sample task, a measure of visual recognition memory, up to criterion of 90% correct responses on each of the four delays (10s, 30s, 60s, and 90s). They were then tested on two versions of the task: Task 1 included the four delays intermixed within a session and the monkeys performed it with the accuracy of 90%. Task 2 included, in each of 24 trials, a list of six objects presented in succession. Two objects from the list were then presented for choice paired with novel objects and following two of the four delays intermixed within a session. This task with a higher mnemonic demand yielded an average performance of 64% correct. Oral administration of huperzine A did not significantly affect the monkeys' performance on either task. However, a significant negative correlation was found between the baseline performance on each delay and the change in performance under huperzine A, suggesting that under conditions in which the subjects were performing poorly (55-69%), the drug resulted in improved performance, whereas no improvement was obtained when the baseline was close to 90%. In fact, when the subjects were performing very well, huperzine A tended to reduce the performance accuracy, indicating that in a system that functions optimally, the increased availability of acetylcholine does not improve performance or memory, especially when the animals are close to the maximum performance. In contrast, oral administration of IDRA 21 significantly improved performance on Task 2, especially on the longest delay. This finding supports the potential use of this drug in treatment of cognitive and memory disorders. This article is part of a Special Issue entitled 'Trends in neuropharmacology: in memory of Erminio Costa'.
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Affiliation(s)
- Ludise Malkova
- Department of Pharmacology and the Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, 3900 Reservoir Rd. NW, Washington, DC 20007, USA.
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Herkert NM, Aurbek N, Eyer P, Thiermann H, Worek F. Comparative study of oxime-induced reactivation of erythrocyte and muscle AChE from different animal species following inhibition by sarin or paraoxon. Toxicol Lett 2010; 194:94-101. [DOI: 10.1016/j.toxlet.2010.02.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 02/05/2010] [Accepted: 02/05/2010] [Indexed: 11/28/2022]
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Haigh JR, Adler M, Apland JP, Deshpande SS, Barham CB, Desmond P, Koplovitz I, Lenz DE, Gordon RK. Protection by pyridostigmine bromide of marmoset hemi-diaphragm acetylcholinesterase activity after soman exposure. Chem Biol Interact 2010; 187:416-20. [PMID: 20144889 DOI: 10.1016/j.cbi.2010.02.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 01/29/2010] [Accepted: 02/01/2010] [Indexed: 11/25/2022]
Abstract
Pyridostigmine bromide (PB) was approved by the U.S. Food and Drug Administration (FDA) in 2003 as a pretreatment in humans against the lethal effects of the irreversible nerve agent soman (GD). Organophosphate (OP) chemical warfare agents such as GD exert their toxic effects by inhibiting acetylcholinesterase (AChE) from terminating the action of acetylcholine at postsynaptic sites in cholinergic nerve terminals (including crucial peripheral muscle such as diaphragm). As part of the post-marketing approval of PB, the FDA required (under 21CFR314, the "two animal rule") the study of a non-human primate model (the common marmoset Callithrix jacchus jacchus) to demonstrate increased survival against lethal GD poisoning, and protection of physiological hemi-diaphragm function after PB pretreatment and subsequent GD exposure. Marmosets (male and female) were placed in the following experimental groups: (i) control (saline pretreatment only), (ii) low dose PB (12.5 microg/kg), or (iii) high dose (39.5 microg/kg) PB. Thirty minutes after the PB dose, animals were challenged with either saline (control) or soman (GD, 45 microg/kg), followed 1 min later by atropine (2mg/kg) and 2-PAM (25mg/kg). After a further 16 min, animals were euthanized and the complete diaphragm removed; the right hemi-diaphragm was frozen immediately at -80 degrees C, and the left hemi-diaphragm was placed in a tissue bath for 4h (to allow for decarbamylation to occur), then frozen. AChE activities were determined using the automated WRAIR cholinesterase assay. Blood samples were collected for AChE activities prior to PB, before GD challenge, and after sacrifice. RBC-AChE was inhibited by approximately 18% and 50% at the low and high doses of PB, respectively, compared to control (baseline) activity. In the absence of PB pretreatment, the inhibition of RBC-AChE by GD was 98%. The recovery of hemi-diaphragm AChE activity after the 4h wash period (decarbamylation) was approximately 8% and 17%, at the low and high PB doses, respectively, compared with the baseline (control) AChE activity prior to PB pretreatment or soman exposure. The results suggest that PB pretreatment protects a critical fraction of AChE activity in the marmoset diaphragm, which is sufficient to allow the animal to breathe despite exposure to a dose of soman that is lethal in unprotected animals.
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Affiliation(s)
- Julian R Haigh
- Department of Regulated Laboratories, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
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Žďárová Karasová J, Bajgar J, Novotný L, Kuča K. Is a high dose of Huperzine A really suitable for pretreatment against high doses of soman? J Appl Biomed 2009. [DOI: 10.32725/jab.2009.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Protection of red blood cell acetylcholinesterase by oral huperzine A against ex vivo soman exposure: Next generation prophylaxis and sequestering of acetylcholinesterase over butyrylcholinesterase. Chem Biol Interact 2008; 175:380-6. [DOI: 10.1016/j.cbi.2008.04.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 04/22/2008] [Accepted: 04/23/2008] [Indexed: 11/18/2022]
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Identical kinetics of human erythrocyte and muscle acetylcholinesterase with respect to carbamate pre-treatment, residual activity upon soman challenge and spontaneous reactivation after withdrawal of the inhibitors. Toxicology 2008; 246:188-92. [DOI: 10.1016/j.tox.2008.01.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 01/10/2008] [Accepted: 01/11/2008] [Indexed: 11/18/2022]
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Eckert S, Eyer P, Melzer M, Thiermann H, Worek F. Effects of oximes on rate of decarbamylation of human red blood cell AChE measured with two different methods. Biochem Pharmacol 2008; 75:1561-6. [DOI: 10.1016/j.bcp.2008.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 01/04/2008] [Accepted: 01/04/2008] [Indexed: 11/26/2022]
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Eckert S, Eyer P, Herkert N, Bumm R, Weber G, Thiermann H, Worek F. Comparison of the oxime-induced reactivation of erythrocyte and muscle acetylcholinesterase following inhibition by sarin or paraoxon, using a perfusion model for the real-time determination of membrane-bound acetylcholinesterase activity. Biochem Pharmacol 2008; 75:698-703. [DOI: 10.1016/j.bcp.2007.09.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 09/06/2007] [Accepted: 09/17/2007] [Indexed: 11/26/2022]
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