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Almeida AJD, Hobson BA, Saito N, Bruun DA, Porter VA, Harvey DJ, Garbow JR, Chaudhari AJ, Lein PJ. Quantitative T 2 mapping-based longitudinal assessment of brain injury and therapeutic rescue in the rat following acute organophosphate intoxication. Neuropharmacology 2024; 249:109895. [PMID: 38437913 PMCID: PMC11227117 DOI: 10.1016/j.neuropharm.2024.109895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 02/07/2024] [Accepted: 02/29/2024] [Indexed: 03/06/2024]
Abstract
Acute intoxication with organophosphate (OP) cholinesterase inhibitors poses a significant public health risk. While currently approved medical countermeasures can improve survival rates, they often fail to prevent chronic neurological damage. Therefore, there is need to develop effective therapies and quantitative metrics for assessing OP-induced brain injury and its rescue by these therapies. In this study we used a rat model of acute intoxication with the OP, diisopropylfluorophosphate (DFP), to test the hypothesis that T2 measures obtained from brain magnetic resonance imaging (MRI) scans provide quantitative metrics of brain injury and therapeutic efficacy. Adult male Sprague Dawley rats were imaged on a 7T MRI scanner at 3, 7 and 28 days post-exposure to DFP or vehicle (VEH) with or without treatment with the standard of care antiseizure drug, midazolam (MDZ); a novel antiseizure medication, allopregnanolone (ALLO); or combination therapy with MDZ and ALLO (DUO). Our results show that mean T2 values in DFP-exposed animals were: (1) higher than VEH in all volumes of interest (VOIs) at day 3; (2) decreased with time; and (3) decreased in the thalamus at day 28. Treatment with ALLO or DUO, but not MDZ alone, significantly decreased mean T2 values relative to untreated DFP animals in the piriform cortex at day 3. On day 28, the DUO group showed the most favorable T2 characteristics. This study supports the utility of T2 mapping for longitudinally monitoring brain injury and highlights the therapeutic potential of ALLO as an adjunct therapy to mitigate chronic morbidity associated with acute OP intoxication.
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Affiliation(s)
- Alita Jesal D Almeida
- Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA; Department of Radiology, University of California-Davis School of Medicine, Sacramento, CA, 95817, USA.
| | - Brad A Hobson
- Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA.
| | - Naomi Saito
- Department of Public Health Sciences, University of California-Davis School of Medicine, Davis, CA, 95616, USA
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California-Davis School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Valerie A Porter
- Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA; Department of Radiology, University of California-Davis School of Medicine, Sacramento, CA, 95817, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California-Davis School of Medicine, Davis, CA, 95616, USA.
| | - Joel R Garbow
- Department of Radiology, Washington University School of Medicine, St Louis, MO, 63110, USA.
| | - Abhijit J Chaudhari
- Department of Radiology, University of California-Davis School of Medicine, Sacramento, CA, 95817, USA; Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California-Davis School of Veterinary Medicine, Davis, CA, 95616, USA.
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2
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Shulaeva MM, Zueva IV, Nikolaev AE, Saifina LF, Sharafutdinova DR, Babaev VM, Semenov VE, Petrov KA. Conjugates of nucleobases with triazole-hydroxamic acids for the reactivation of acetylcholinesterase and treatment of delayed neurodegeneration induced by organophosphate poisoning. Bioorg Chem 2023; 141:106858. [PMID: 37774432 DOI: 10.1016/j.bioorg.2023.106858] [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: 07/19/2023] [Revised: 08/26/2023] [Accepted: 09/09/2023] [Indexed: 10/01/2023]
Abstract
A series of new uncharged conjugates of adenine, 3,6-dimetyl-, 1,6-dimethyl- and 6-methyluracil with 1,2,4-triazole-3-hydroxamic and 1,2,3-triazole-4-hydroxamic acid moieties were synthesized and studied as reactivators of organophosphate-inhibited cholinesterase. It is shown that triazole-hydroxamic acids can reactivate acetylcholinesterase (AChE) inhibited by paraoxon (POX) in vitro, offering reactivation constants comparable to those of pralidoxime (2-PAM). However, in contrast to 2-PAM, triazole-hydroxamic acids demonstrated the ability to reactivate AChE in the brain of rats poisoned with POX. At a dose of 200 mg/kg (i.v.), the lead compound 3e reactivated 22.6 ± 7.3% of brain AChE in rats poisoned with POX. In a rat model of POX-induced delayed neurodegeneration, compound 3e reduced the neuronal injury labeled with FJB upon double administration 1 and 3 h after poisoning. Compound 3e was also shown to prevent memory impairment of POX-poisoned rats as tested in a Morris water maze.
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Affiliation(s)
- Marina M Shulaeva
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - 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 420088, Russian Federation
| | - Anton E Nikolaev
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - Liliya F Saifina
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - Dilyara R Sharafutdinova
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - Vasily M Babaev
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - 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 420088, Russian Federation.
| | - 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 420088, Russian Federation; Kazan Federal University, Kremlyovskaya str., 18, Kazan 420008, Russian Federation
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3
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Aracava Y, Albuquerque EX, Pereira EFR. (R,S)-trihexyphenidyl, acting via a muscarinic receptor-independent mechanism, inhibits hippocampal glutamatergic and GABAergic synaptic transmissions: Potential relevance for treatment of organophosphorus intoxication. Neuropharmacology 2023; 239:109684. [PMID: 37549771 PMCID: PMC10590273 DOI: 10.1016/j.neuropharm.2023.109684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
Preclinical studies have reported that, compared to the muscarinic receptor (mAChR) antagonist atropine, (R,S)-trihexyphenidyl (THP) more effectively counters the cholinergic crisis, seizures, and neuropathology triggered by organophosphorus (OP)-induced acetylcholinesterase (AChE) inhibition. The greater effectiveness of THP was attributed to its ability to block mAChRs and N-methyl-d-aspartate-type glutamatergic receptors (NMDARs) in the brain. However, THP also inhibits α7 nicotinic receptors (nAChRs). The present study examined whether THP-induced inhibition of mAChRs, α7 nAChRs, and NMDARs is required to suppress glutamatergic synaptic transmission, whose overstimulation sustains OP-induced seizures. In primary hippocampal cultures, THP (1-30 μM) suppressed the frequency of excitatory and inhibitory postsynaptic currents (EPSCs and IPSCs, respectively) recorded from neurons in nominally Mg2+-free solution. A single sigmoidal function adequately fit the overlapping concentration-response relationships for THP-induced suppression of IPSC and EPSC frequencies yielding an IC50 of 6.3 ± 1.3 μM. Atropine (1 μM), the NMDAR antagonist d,l-2-amino-5-phosphonopentanoic acid (D,L-AP5, 50 μM), and the α7 nAChR antagonist methyllycaconitine (MLA, 10 nM) did not prevent THP-induced inhibition of synaptic transmission. THP (10 μM) did not affect the probability of transmitter release because it had no effect on the frequency of miniature IPSCs and EPSCs recorded in the presence of tetrodotoxin. Additionally, THP had no effect on the amplitudes and decay-time constants of miniature IPSCs and EPSCs; therefore, it did not affect the activity of postsynaptic GABAA and glutamate receptors. This study provides the first demonstration that THP can suppress action potential-dependent synaptic transmission via a mechanism independent of NMDAR, mAChR, and α7 nAChR inhibition.
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Affiliation(s)
- Yasco Aracava
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Edson X Albuquerque
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Edna F R Pereira
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA.
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4
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Zhao D, Liu J, Zhou Y, Zhang L, Zhong Y, Yang Y, Zhao B, Yang M, Wang Y. Penetrating the Blood-Brain Barrier for Targeted Treatment of Neurotoxicant Poisoning by Nanosustained-Released 2-PAM@VB1-MIL-101-NH 2(Fe). ACS APPLIED MATERIALS & INTERFACES 2023; 15:12631-12642. [PMID: 36867458 DOI: 10.1021/acsami.2c18929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
It is very important to establish a sustained-release pralidoxime chloride (2-PAM) drug system with brain targeting function for the treatment of neurotoxicant poisoning. Herein, Vitamin B1 (VB1), also known as thiamine, which can specifically bind to the thiamine transporter on the surface of the blood-brain barrier, was incorporated onto the surface of MIL-101-NH2(Fe) nanoparticles with a size of ∼100 nm. Pralidoxime chloride was further loaded within the interior of the above resulted composite by soaking, and a resulting composite drug (denoted as 2-PAM@VB1-MIL-101-NH2(Fe)) with a loading capacity of 14.8% (wt) was obtained. The results showed that the drug release rate of the composite drug was increased in PBS solution with the increase of pH (2-7.4) and a maximum drug release rate of 77.5% at pH 4. Experiments on the treatment of poisoning by gavage with the nerve agent sarin in mice combined with atropine revealed that sustained release of 2-PAM from the composite drug was achieved for more than 72 h. Sustained and stable reactivation of poisoned acetylcholinesterase (AChE) was observed with an enzyme reactivation rate of 42.7% in the ocular blood samples at 72 h. By using both zebrafish brain and mouse brain as models, we found that the composite drug could effectively cross the blood-brain barrier and restore the AChE activity in the brain of poisoned mice. The composite drug is expected to be a stable therapeutic drug with brain targeting and prolonged drug release properties for nerve agent intoxication in the middle and late stages of treatment.
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Affiliation(s)
- Dianfa Zhao
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
- Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P. R. China
| | - Jie Liu
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
- Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P. R. China
| | - Yunshan Zhou
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Lijuan Zhang
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Yuxu Zhong
- Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P. R. China
| | - Yang Yang
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Baoquan Zhao
- Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P. R. China
| | - Mengru Yang
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, P. R. China
| | - Yong'an Wang
- Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P. R. China
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5
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Weitman M, Eisenkraft A, TaShma Z, Makarovsky I, Last D, Daniels D, Guez D, Shneor R, Mardor Y, Nudelman A, Krivoy A. Synthesis and preliminary biological evaluation of gabactyzine, a benactyzine-GABA mutual prodrug, as an organophosphate antidote. Sci Rep 2022; 12:18078. [PMID: 36302937 PMCID: PMC9613653 DOI: 10.1038/s41598-022-23141-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/25/2022] [Indexed: 01/09/2023] Open
Abstract
Organophosphates (OPs) are inhibitors of acetylcholinesterase and have deleterious effects on the central nervous system. Clinical manifestations of OP poisoning include convulsions, which represent an underlying toxic neuro-pathological process, leading to permanent neuronal damage. This neurotoxicity is mediated through the cholinergic, GABAergic and glutamatergic (NMDA) systems. Pharmacological interventions in OP poisoning are designed to mitigate these specific neuro-pathological pathways, using anticholinergic drugs and GABAergic agents. Benactyzine is a combined anticholinergic, anti-NMDA compound. Based on previous development of novel GABA derivatives (such as prodrugs based on perphenazine for the treatment of schizophrenia and nortriptyline against neuropathic pain), we describe the synthesis and preliminary testing of a mutual prodrug ester of benactyzine and GABA. It is assumed that once the ester crosses the blood-brain-barrier it will undergo hydrolysis, releasing benactyzine and GABA, which are expected to act synergistically. The combined release of both compounds in the brain offers several advantages over the current OP poisoning treatment protocol: improved efficacy and safety profile (where the inhibitory properties of GABA are expected to counteract the anticholinergic cognitive adverse effects of benactyzine) and enhanced chemical stability compared to benactyzine alone. We present here preliminary results of animal studies, showing promising results with early gabactyzine administration.
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Affiliation(s)
- Michal Weitman
- grid.22098.310000 0004 1937 0503Chemistry Department, Bar Ilan University, 52900 Ramat Gan, Israel
| | - Arik Eisenkraft
- grid.9619.70000 0004 1937 0538The Institute for Research in Military Medicine, The Hebrew University Faculty of Medicine and The IDF Medical Corps, Jerusalem, Israel ,The IDF Medical Corps Headquarters, Ramat Gan, Israel
| | - Zeev TaShma
- The IDF Medical Corps Headquarters, Ramat Gan, Israel
| | - Igor Makarovsky
- grid.22098.310000 0004 1937 0503Chemistry Department, Bar Ilan University, 52900 Ramat Gan, Israel
| | - David Last
- grid.413795.d0000 0001 2107 2845The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Dianne Daniels
- grid.413795.d0000 0001 2107 2845The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel
| | - David Guez
- grid.413795.d0000 0001 2107 2845The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Ran Shneor
- grid.413795.d0000 0001 2107 2845The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Yael Mardor
- grid.413795.d0000 0001 2107 2845The Advanced Technology Center, Sheba Medical Center, Ramat-Gan, Israel ,grid.12136.370000 0004 1937 0546Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Abraham Nudelman
- grid.22098.310000 0004 1937 0503Chemistry Department, Bar Ilan University, 52900 Ramat Gan, Israel
| | - Amir Krivoy
- The IDF Medical Corps Headquarters, Ramat Gan, Israel ,grid.415340.70000 0004 0403 0450Geha Mental Health Center, Petach-Tikva, Israel
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6
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Gore A, Neufeld-Cohen A, Egoz I, Baranes S, Gez R, Efrati R, David T, Dekel Jaoui H, Yampolsky M, Grauer E, Chapman S, Lazar S. Neuroprotection by delayed triple therapy following sarin nerve agent insult in the rat. Toxicol Appl Pharmacol 2021; 419:115519. [PMID: 33823148 DOI: 10.1016/j.taap.2021.115519] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/25/2021] [Accepted: 04/01/2021] [Indexed: 02/08/2023]
Abstract
The development of refractory status epilepticus (SE) induced by sarin intoxication presents a therapeutic challenge. In our current research we evaluate the efficacy of a delayed combined triple treatment in ending the abnormal epileptiform seizure activity (ESA) and the ensuing of long-term neuronal insult. SE was induced in male Sprague-Dawley rats by exposure to 1.2LD50 sarin insufficiently treated by atropine and TMB4 (TA) 1 min later. Triple treatment of ketamine, midazolam and valproic acid was administered 30 min or 1 h post exposure and was compared to a delayed single treatment with midazolam alone. Toxicity and electrocorticogram activity were monitored during the first week and behavioral evaluation performed 3 weeks post exposure followed by brain biochemical and immunohistopathological analyses. The addition of both single and triple treatments reduced mortality and enhanced weight recovery compared to the TA-only treated group. The triple treatment also significantly minimized the duration of the ESA, reduced the sarin-induced increase in the neuroinflammatory marker PGE2, the brain damage marker TSPO, decreased the gliosis, astrocytosis and neuronal damage compared to the TA+ midazolam or only TA treated groups. Finally, the triple treatment eliminated the sarin exposed increased open field activity, as well as impairing recognition memory as seen in the other experimental groups. The delayed triple treatment may serve as an efficient therapy, which prevents brain insult propagation following sarin-induced refractory SE, even if treatment is postponed for up to 1 h.
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Affiliation(s)
- Ariel Gore
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel.
| | - Adi Neufeld-Cohen
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Inbal Egoz
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Shlomi Baranes
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Rellie Gez
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Rahav Efrati
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Tse'ela David
- The Veterinary Center for Pre-clinical Research, Israel Institute for Biological, Chemical and Environmental Sciences, Ness- Ziona 74100, Israel
| | - Hani Dekel Jaoui
- The Veterinary Center for Pre-clinical Research, Israel Institute for Biological, Chemical and Environmental Sciences, Ness- Ziona 74100, Israel
| | - Michael Yampolsky
- The Veterinary Center for Pre-clinical Research, Israel Institute for Biological, Chemical and Environmental Sciences, Ness- Ziona 74100, Israel
| | - Ettie Grauer
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Shira Chapman
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel
| | - Shlomi Lazar
- Department of Pharmacology, Israel Institute for Biological, Chemical and Environmental Sciences, Ness-Ziona 74100, Israel.
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Reddy SD, Wu X, Kuruba R, Sridhar V, Reddy DS. Magnetic resonance imaging analysis of long-term neuropathology after exposure to the nerve agent soman: correlation with histopathology and neurological dysfunction. Ann N Y Acad Sci 2020; 1480:116-135. [PMID: 32671850 PMCID: PMC7708405 DOI: 10.1111/nyas.14431] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 05/09/2020] [Accepted: 06/17/2020] [Indexed: 12/14/2022]
Abstract
Nerve agents (NAs) produce acute and long-term brain injury and dysfunction, as evident from the Japan and Syria incidents. Magnetic resonance imaging (MRI) is a versatile technique to examine such chronic anatomical, functional, and neuronal damage in the brain. The objective of this study was to investigate long-term structural and neuronal lesion abnormalities in rats exposed to acute soman intoxication. T2-weighted MRI images of 10 control and 17 soman-exposed rats were acquired using a Siemens MRI system at 90 days after soman exposure. Quantification of brain tissue volumes and T2 signal intensity was conducted using the Inveon Research Workplace software and the extent of damage was correlated with histopathology and cognitive function. Soman-exposed rats showed drastic hippocampal atrophy with neuronal loss and reduced hippocampal volume (HV), indicating severe damage, but had similar T2 relaxation times to the control group, suggesting limited scarring and fluid density changes despite the volume decrease. Conversely, soman-exposed rats displayed significant increases in lateral ventricle volumes and T2 times, signifying strong cerebrospinal fluid expansion in compensation for tissue atrophy. The total brain volume, thalamic volume, and thalamic T2 time were similar in both groups, however, suggesting that some brain regions remained more intact long-term after soman intoxication. The MRI neuronal lesions were positively correlated with the histological markers of neurodegeneration and neuroinflammation 90 days after soman exposure. The predominant MRI hippocampal atrophy (25%) was highly consistent with massive reduction (35%) of neuronal nuclear antigen-positive (NeuN+ ) principal neurons and parvalbumin-positive (PV+ ) inhibitory interneurons within this brain region. The HV was significantly correlated with both inflammatory markers of GFAP+ astrogliosis and IBA1+ microgliosis. The reduced HV was also directly correlated with significant memory deficits in the soman-exposed cohort, confirming a possible neurobiological basis for neurological dysfunction. Together, these findings provide powerful insight on long-term region-specific neurodegenerative patterns after soman exposure and demonstrate the feasibility of in vivo neuroimaging to monitor neuropathology, predict the risk of neurological deficits, and evaluate response to medical countermeasures for NAs.
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Affiliation(s)
- Sandesh D Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
- Biomedical Engineering, College of Engineering, Texas A&M University, College Station, Texas
| | - Xin Wu
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
| | - Ramkumar Kuruba
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
| | - Vidya Sridhar
- Texas A&M Institute for Preclinical Studies, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
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8
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Hobson BA, Rowland DJ, Sisó S, Guignet MA, Harmany ZT, Bandara SB, Saito N, Harvey DJ, Bruun DA, Garbow JR, Chaudhari AJ, Lein PJ. TSPO PET Using [18F]PBR111 Reveals Persistent Neuroinflammation Following Acute Diisopropylfluorophosphate Intoxication in the Rat. Toxicol Sci 2020; 170:330-344. [PMID: 31087103 DOI: 10.1093/toxsci/kfz096] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Acute intoxication with organophosphates (OPs) can trigger status epilepticus followed by persistent cognitive impairment and/or electroencephalographic abnormalities. Neuroinflammation is widely posited to influence these persistent neurological consequences. However, testing this hypothesis has been challenging, in part because traditional biometrics preclude longitudinal measures of neuroinflammation within the same animal. Therefore, we evaluated the performance of noninvasive positron emission tomography (PET), using the translocator protein (TSPO) radioligand [18F]PBR111 against classic histopathologic measures of neuroinflammation in a preclinical model of acute intoxication with the OP diisopropylfluorophosphate (DFP). Adult male Sprague Dawley rats administered pyridostigmine bromide (0.1 mg/kg, im) 30 min prior to administration of DFP (4 mg/kg, sc), atropine sulfate (2 mg/kg, im) and 2-pralidoxime (25 mg/kg, im) exhibited moderate-to-severe seizure behavior. TSPO PET performed prior to DFP exposure and at 3, 7, 14, 21, and 28 days postexposure revealed distinct lesions, as defined by increased standardized uptake values (SUV). Increased SUV showed high spatial correspondence to immunohistochemical evidence of neuroinflammation, which was corroborated by cytokine gene and protein expression. Regional SUV metrics varied spatiotemporally with days postexposure and correlated with the degree of neuroinflammation detected immunohistochemically. Furthermore, SUV metrics were highly correlated with seizure severity, suggesting that early termination of OP-induced seizures may be critical for attenuating subsequent neuroinflammatory responses. Normalization of SUV values to a cerebellar reference region improved correlations to all outcome measures and seizure severity. Collectively, these results establish TSPO PET using [18F]PBR111 as a robust, noninvasive tool for longitudinal monitoring of neuroinflammation following acute OP intoxication.
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Affiliation(s)
- Brad A Hobson
- Department of Radiology, University of California Davis School of Medicine, Sacramento, California 95817
| | - Douglas J Rowland
- Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California Davis College of Engineering, Davis, California 95616
| | - Sílvia Sisó
- Department of Pathology, Microbiology and Immunology
| | - Michelle A Guignet
- Department of Molecular Biosciences, University of California Davis School of Veterinary Medicine, Davis, California 95616
| | - Zachary T Harmany
- Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California Davis College of Engineering, Davis, California 95616
| | - Suren B Bandara
- Department of Molecular Biosciences, University of California Davis School of Veterinary Medicine, Davis, California 95616
| | - Naomi Saito
- Department of Public Health Sciences, University of California Davis School of Medicine, Davis, California 95616
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California Davis School of Medicine, Davis, California 95616
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California Davis School of Veterinary Medicine, Davis, California 95616
| | - Joel R Garbow
- Department of Radiology, Washington University in St. Louis, St. Louis, Missouri 63110
| | - Abhijit J Chaudhari
- Department of Radiology, University of California Davis School of Medicine, Sacramento, California 95817.,Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California Davis College of Engineering, Davis, California 95616
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California Davis School of Veterinary Medicine, Davis, California 95616
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9
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Cornelissen AS, Klaassen SD, van Groningen T, Bohnert S, Joosen MJA. Comparative physiology and efficacy of atropine and scopolamine in sarin nerve agent poisoning. Toxicol Appl Pharmacol 2020; 396:114994. [PMID: 32251685 DOI: 10.1016/j.taap.2020.114994] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 03/30/2020] [Accepted: 04/02/2020] [Indexed: 01/20/2023]
Abstract
Anticholinergic treatment is key for effective medical treatment of nerve agent exposure. Atropine is included at a 2 mg intramuscular dose in so-called autoinjectors designed for self- and buddy-aid. As patient cohorts are not available, predicting and evaluating the efficacy of medical countermeasures relies on animal models. The use of atropine as a muscarinic antagonist is based on efficacy achieved in studies in a variety of species. The dose of atropine administered varies considerably across these studies. This is a complicating factor in the prediction of efficacy in the human situation, largely because atropine dosing also influences therapeutic efficacy of oximes and anticonvulsants generally part of the treatment administered. To improve translation of efficacy of dosing regimens, including pharmacokinetics and physiology provide a promising approach. In the current study, pharmacokinetics and physiological parameters obtained using EEG and ECG were assessed in naïve rats and in sarin-exposed rats for two anticholinergic drugs, atropine and scopolamine. The aim was to find a predictive parameter for therapeutic efficacy. Scopolamine and atropine showed a similar bioavailability, but brain levels reached were much higher for scopolamine. Scopolamine exhibited a dose-dependent loss of beta power in naïve animals, whereas atropine did not show any such central effect. This effect was correlated with an enhanced anticonvulsant effect of scopolamine compared to atropine. These findings show that an approach including pharmacokinetics and physiology could contribute to improved dose scaling across species and assessing the therapeutic potential of similar anticholinergic and anticonvulsant drugs against nerve agent poisoning.
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Affiliation(s)
- Alex S Cornelissen
- TNO Defense, Security and Safety, CBRN Protection, Lange Kleiweg 137, 2288, GJ, Rijswijk, the Netherlands.
| | - Steven D Klaassen
- TNO Defense, Security and Safety, CBRN Protection, Lange Kleiweg 137, 2288, GJ, Rijswijk, the Netherlands
| | - Tomas van Groningen
- TNO Defense, Security and Safety, CBRN Protection, Lange Kleiweg 137, 2288, GJ, Rijswijk, the Netherlands
| | - Sara Bohnert
- Defence Research and Development Canada-Suffield Research Centre, Department of National Defence, Suffield, Alberta, Canada
| | - Marloes J A Joosen
- TNO Defense, Security and Safety, CBRN Protection, Lange Kleiweg 137, 2288, GJ, Rijswijk, the Netherlands
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10
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Zorbaz T, Mišetić P, Probst N, Žunec S, Zandona A, Mendaš G, Micek V, Maček Hrvat N, Katalinić M, Braïki A, Jean L, Renard PY, Gabelica Marković V, Kovarik Z. Pharmacokinetic Evaluation of Brain Penetrating Morpholine-3-hydroxy-2-pyridine Oxime as an Antidote for Nerve Agent Poisoning. ACS Chem Neurosci 2020; 11:1072-1084. [PMID: 32105443 DOI: 10.1021/acschemneuro.0c00032] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Nerve agents, the deadliest chemical warfare agents, are potent inhibitors of acetylcholinesterase (AChE) and cause rapid cholinergic crisis with serious symptoms of poisoning. Oxime reactivators of AChE are used in medical practice in the treatment of nerve agent poisoning, but the search for novel improved reactivators with central activity is an ongoing pursuit. For numerous oximes synthesized, in vitro reactivation is a standard approach in biological evaluation with little attention given to the pharmacokinetic properties of the compounds. This study reports a comprehensive physicochemical, pharmacokinetic, and safety profiling of five lipophilic 3-hydroxy-2-pyridine aldoximes, which were recently shown to be potent AChE reactivators with a potential to be centrally active. The oxime JR595 was singled out as highly metabolically stable in human liver microsomes, noncytotoxic oxime for SH-SY5Y neuroblastoma and 1321N1 astrocytoma cell lines, and its pharmacokinetic profile was determined after intramuscular administration in mice. JR595 was rapidly absorbed into blood after 15 min with simultaneous distribution to the brain at up to about 40% of its blood concentration; however, it was eliminated from both the brain and blood within an hour. In addition, the MDCKII-MDR1 cell line assay showed that oxime JR595 was not a P-glycoprotein efflux pump substrate. Finally, the preliminary antidotal study against multiple LD50 doses of VX and sarin in mice showed the potential of JR595 to provide desirable therapeutic outcomes with future improvements in its circulation time.
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Affiliation(s)
- Tamara Zorbaz
- Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia
| | - Petra Mišetić
- Fidelta Ltd, Prilaz baruna Filipovića 29, HR-10000 Zagreb, Croatia
| | - Nicolas Probst
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, COBRA (UMR 6014), 76000 Rouen, France
| | - Suzana Žunec
- Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia
| | - Antonio Zandona
- Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia
| | - Gordana Mendaš
- Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia
| | - Vedran Micek
- Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia
| | - Nikolina Maček Hrvat
- Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia
| | - Maja Katalinić
- Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia
| | - Anissa Braïki
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, COBRA (UMR 6014), 76000 Rouen, France
| | - Ludovic Jean
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, COBRA (UMR 6014), 76000 Rouen, France
| | - Pierre-Yves Renard
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, COBRA (UMR 6014), 76000 Rouen, France
| | - Vesna Gabelica Marković
- Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, HR-10000 Zagreb, Croatia
| | - Zrinka Kovarik
- Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia
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11
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Gore A, Neufeld-Cohen A, Egoz I, Baranes S, Gez R, Grauer E, Chapman S, Lazar S. Efficacy of retigabine in ameliorating the brain insult following sarin exposure in the rat. Toxicol Appl Pharmacol 2020; 395:114963. [PMID: 32209366 DOI: 10.1016/j.taap.2020.114963] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Sarin is an irreversible organophosphate cholinesterase inhibitor. Following toxic signs, an extensive long-term brain damage is often reported. Thus, we evaluated the efficacy of a novel anticonvulsant drug retigabine, a modulator of neuronal voltage gated K+ channels, as a neuroprotective agent following sarin exposure. METHODS Rats were exposed to 1 LD50 or 1.2 LD50 sarin and treated at onset of convulsions with retigabine (5 mg/kg, i.p.) alone or in combination with 5 mg/kg atropine and 7.5 mg/kg TMB-4 (TA) respectively. Brain biochemical and immunohistopathological analyses were processed 24 h and 1 week following 1 LD50 sarin exposure and at 4 weeks following exposure to 1.2 LD50 sarin. EEG activity in freely moving rats was also monitored by telemetry during the first week following exposure to 1.2 LD50 and behavior in the Open Field was evaluated 3 weeks post exposure. RESULTS Treatment with retigabine following 1 LD50 sarin exposure or in combination with TA following 1.2 LD50 exposure significantly reduced mortality rate compared to the non-treated groups. In both experiments, the retigabine treatment significantly reduced gliosis, astrocytosis and brain damage as measured by translocator protein (TSPO). Following sarin exposure the combined treatment (retigabine+ TA) significantly minimized epileptiform seizure activity. Finally, in the Open Field behavioral test the non-treated sarin group showed an increased mobility which was reversed by the combined treatment. CONCLUSIONS The M current modulator retigabine has been shown to be an effective adjunct therapy following OP induced convulsion, minimizing epileptiform seizure activity and attenuating the ensuing brain damage.
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Affiliation(s)
- Ariel Gore
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
| | - Adi Neufeld-Cohen
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Inbal Egoz
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shlomi Baranes
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Rellie Gez
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Ettie Grauer
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shira Chapman
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shlomi Lazar
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
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Kassa J, Koupilová M, Herink J, Vachek J. The Long Term Influence of Low-Level Sarin Exposure on Behavioral and Neurophysiological Functions in Rats. ACTA MEDICA (HRADEC KRÁLOVÉ) 2019. [DOI: 10.14712/18059694.2019.82] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
1. Long term effects of low doses of highly toxic organophosphorus agent sarin on behavioral and neurophysiological functions were studied in rats exposed to sarin by inhalation. The toxic effects of sarin were monitored using a functional observational battery (FOB), an automatic measurement of motor activity and a test of excitability of central nervous system at 3, 6 and 12 months following sarin exposure. 2. The results indicate that sarin at symptomatic as well as asymptomatic doses (level 2 and 3) is able to induce some neurotoxic effects (a decrease in activity and mobility, an alteration of gait, an increase in stereotyped behavior) including an increase in the excitability of central nervous system (an increase in convulsive activity following the administration of pentamethylenetetrazole) in rats at 3 months following inhalation exposure. Some sings of increased excitability were also observed in sarin-exposed rats following 6 or 12 months (an increase in exploratory activity, body temperature and a hindlimb grip strength at 6 months following exposure to sarin at asymptomatic doses, an increase in tail-pinch response at 12 months following exposure to sarin at symptomatic doses). 3. Therefore, nerve agents such as sarin seem to be harmful not only at high, clinically symptomatic doses but also at low, clinically asymptomatic doses because of long term manifestation of alteration of neurophysiological functions in sarin-exposed rats without disruption of cholinergic nervous system.
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Chapman S, Lazar S, Gez R, Rabinovitz I, Yaakov G, Grauer E. Lung damage following whole body, but not intramuscular, exposure to median lethality dose of sarin: findings in rats and guinea pigs. Inhal Toxicol 2019; 31:203-211. [PMID: 31359796 DOI: 10.1080/08958378.2019.1644402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Objective: Sarin is an irreversible organophosphate cholinesterase inhibitor and a highly toxic, volatile warfare agent. Rats and guinea pigs exposed to sarin display cholinergic excitotoxicity which includes hyper-salivation, respiratory distress, tremors, seizures, and death. Here we focused on the characterization of the airways injury induced by direct exposure of the lungs to sarin vapor and compared it to that induced by the intramuscularly route. Materials and methods: Rats were exposed to sarin either in vapor (∼1LCT50, 34.2 ± 0.8 µg/l/min, 10 min) or by i.m. (∼1LD50, 80 µg/kg), and lung injury was evaluated by broncho-alveolar lavage (BAL). Results and discussion: BAL analysis revealed route-dependent effects in rats: vapor exposed animals showed elevation of inflammatory cytokines, protein, and neutrophil cells. These elevations were seen at 24 h and were still significantly higher compared to control values at 1 week following vapor exposure. These elevations were not detected in rats exposed to sarin i.m. Histological evaluation of the brains revealed typical changes following sarin poisoning independent of the route of administration. The airways damage following vapor exposure in rats was also compared to that induced in guinea pigs. The latter showed increased eosinophilia and histamine levels that constitutes an anaphylactic response not seen in rats. Conclusions: These data clearly point out the importance of using the appropriate route of administration in studying the deleterious effects of volatile nerve agents, as well as the selection of the appropriate animal species. Since airways form major target organs for the development of injury following inhalation toxicity, they should be included in any comprehensive evaluation of countermeasures efficacy.
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Affiliation(s)
- Shira Chapman
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| | - Shlomi Lazar
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| | - Rellie Gez
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| | - Ishai Rabinovitz
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| | - Guy Yaakov
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| | - Ettie Grauer
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
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Time dependent dual effect of anti-inflammatory treatments on sarin-induced brain inflammation: Suggested role of prostaglandins. Neurotoxicology 2019; 74:19-27. [PMID: 31095963 DOI: 10.1016/j.neuro.2019.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/12/2019] [Accepted: 05/12/2019] [Indexed: 11/21/2022]
Abstract
A common consequence of exposure to organophosphate nerve agents is the centrally mediated seizure activity that appears even after conventional treatment with atropine and oximes. We have previously demonstrated a major inflammatory response with subsequent brain damage which was correlated with the duration of the sarin-induced seizures (Chapman et al., 2006). In the present work seizures were induced by the nerve agent sarin (1.2 LD50) insufficiently treated 1 min later by atropine and trimedoxime bromide (TA), with additional midazolam treatment either 5 or 30 min after continuous seizure activity. The efficacy of both steroidal and nonsteroidal anti-inflammatory drugs (NSAIDs), as well as other drugs that were reported as beneficial in neuroprotection, were evaluated for their contribution as adjunct treatment against sarin induced seizures and the ensuing inflammatory brain damage. Results show that both steroids and NSAIDs were harmful when administered during convulsions, and steroids were at best ineffective if administered at their termination. However, if administered at termination of convulsions, the NSAID ibuprofen, the selective COX 2 inhibitor nimesulide and the PLA2 inhibitor quinacrine were partially effective in reducing brain inflammatory markers. Administration of exogenous analogs of prostaglandins (PGE2) immediately following sarin-induced convulsions was found to have a beneficial effect in reducing brain inflammatory markers measured at 24 h and one week post sarin exposure. These findings support the hypothesis that elevated levels of PGE2 have a beneficial role immediately following sarin induced seizures, and that early inhibition of PGE2 production by both steroids and NSAID is contraindicative.
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15
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Caisberger F, Pejchal J, Misik J, Kassa J, Valis M, Kuca K. The benefit of combinations of oximes for the ability of antidotal treatment to counteract sarin-induced brain damage in rats. BMC Pharmacol Toxicol 2018; 19:35. [PMID: 29954446 PMCID: PMC6022407 DOI: 10.1186/s40360-018-0227-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 06/20/2018] [Indexed: 11/22/2022] Open
Abstract
Background The aim of our study was to compare the ability of two combinations of oximes (HI-6 + trimedoxime and HI-6 + K203) with atropine to counteract acute sarin-induced brain damage with the efficacy of antidotal treatment involving single oxime (HI-6) and atropin using in vivo methods. Methods Brain damage and neuroprotective effects of antidotal treatment were evaluated in rats poisoned with sarin at a sublethal dose (108 μg/kg i.m.; 90% LD50) using histopathological, Fluoro-Jade B and Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analysis 24 h after sarin administration. Results Both combinations of oximes reduce the number of rats that died before the end of experiment compared to non-treated sarin poisoning and sarin poisoning treated with HI-6 and atropine. In the case of treatment of sarin poisoning with HI-6 in combination with K203, all rats survived till the end of experiment. HI-6 with atropine was able to reduce sarin-induced brain damage, however, both combinations were slightly more effective. Conclusions The oxime HI-6 in combination with K203 and atropine seems to be the most effective. Thus, both tested oxime combinations bring a small benefit in elimination of acute sarin-induced brain damage compared to single oxime antidotal therapy.
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Affiliation(s)
- Filip Caisberger
- Department of Neurology, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
| | - Jaroslav Pejchal
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Jan Misik
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Jiri Kassa
- Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Martin Valis
- Department of Neurology, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic
| | - Kamil Kuca
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic. .,Biomedical Research Center, Uiversity Hospital Hradec Kralove, Hradec Kralove, Czech Republic.
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Sisó S, Hobson BA, Harvey DJ, Bruun DA, Rowland DJ, Garbow JR, Lein PJ. Editor's Highlight: Spatiotemporal Progression and Remission of Lesions in the Rat Brain Following Acute Intoxication With Diisopropylfluorophosphate. Toxicol Sci 2018; 157:330-341. [PMID: 28329845 DOI: 10.1093/toxsci/kfx048] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Similar to organophosphate (OP) nerve agents, diisopropylfluorophosphate (DFP) rapidly and irreversibly inhibits acetylcholinesterase, leading to convulsions that can progress to status epilepticus (SE). However, in contrast to the OP nerve agents, the long-term consequences of DFP-induced SE are not well known. Thus, we characterized the spatiotemporal profile of neuropathology during the first 2 months following acute DFP intoxication. Adult, male Sprague Dawley rats administered pyridostigmine bromide (0.1 mg/kg, im) 30 min prior to successive administration of DFP (4 mg/kg, sc), atropine sulfate (2 mg/kg, im), and 2-pralidoxime (25 mg/kg, im), exhibited moderate-to-severe seizure behavior, yet survived until euthanized at 0.5 to 60 days post exposure. Analyses of brains and hearts stained with hematoxylin-eosin, or of brains immunostained for neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP), or ionized binding adapter molecule 1 (IBA1), revealed progressive neuronal cell death, neuroinflammation, and tissue remodeling across limbic brain regions and the cerebral cortex, with no detectable pathology in the cerebellum or the heart. The lesion type and progression varied according to brain region and time after exposure. Across multiple brain regions, neuronal necrosis peaked after the first week, and neuroinflammation persisted at least 2 months after intoxication. Notably, mineralization was observed at later times in the thalamus, and to a more limited extent, in the hippocampus. Lesion severity was influenced by the initial seizure severity, and spontaneous recurrent seizures were associated with more severe brain damage. These findings parallel descriptions of neuropathology in preclinical models of acute intoxication with OP nerve agents, and other seizurogenic chemicals, suggesting conserved mechanisms of pathology downstream of chemical-induced SE.
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Affiliation(s)
- Sílvia Sisó
- Translational Biology in the Department of Research, BioMarin Pharmaceuticals Inc, Novato, California, USA
| | - Brad A Hobson
- Department of Molecular Biosciences School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - Danielle J Harvey
- Department of Public Health Sciences School of Medicine, University of California-Davis, Davis, California, USA
| | - Donald A Bruun
- Department of Molecular Biosciences School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - Douglas J Rowland
- Department of Biomedical Engineering and the Center for Molecular and Genomic Imaging College of Engineering, University of California-Davis, Davis, California, USA
| | - Joel R Garbow
- Biomedical Magnetic Resonance Laboratory, Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Pamela J Lein
- Department of Molecular Biosciences School of Veterinary Medicine, University of California-Davis, Davis, California, USA
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Early changes in M2 muscarinic acetylcholine receptors (mAChRs) induced by sarin intoxication may be linked to long lasting neurological effects. Neurotoxicology 2017; 65:248-254. [PMID: 29128314 DOI: 10.1016/j.neuro.2017.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 11/05/2017] [Accepted: 11/05/2017] [Indexed: 01/08/2023]
Abstract
The effect of sarin on the binding parameters (KD & Bmax) of M2 muscarinic acetylcholine receptor (mAChR) was studied 24h and 1 week post exposure. Male & female Sprague-Daweley rats were poisoned with 1XLD50 sarin (80μg/kg, im) followed by treatment of trimedoxime bromide and atropine (7.5:5mg/kg, im) 1min later. Brains were removed and analyzed for M2 mAChR binding, using [3H]AFDX384, an M2 selective antagonist. A significant increase in KD of M2 mAChR was found in the cortex 24h post poisoning, displaying elevation from 4.65±1.16 to 8.45±1.06nM and 5.24±0.93 to 9.29±1.56nM in male and female rats, respectively. A rise in KD was also noted 1 week following exposure from 5.04±1.20 to 11.75±2.78 and from 5.37±1.02 to 11.66±1.73nM, presenting an added increase of 51 and 40% (compared to 24h) in males and females, respectively. Analysis of M2 receptor density (Bmax) revealed a significant reduction of 68% in males and insignificant reduction of 22% in females, 24h after sarin exposure which was followed by 37% recovery in males and 100% recovery in females, 1 week later. These results indicate that sarin induces a long-term decreased affinity in M2 mAChR (elevated KDs) and a transient effect on the number of this receptor subtype (Bmax). We hypothesize that the reduced affinity of the M2 receptors (negative auto-regulatory receptors) may cause long-term brain deficits by impairing the normal regulation release of ACh into the synaptic cleft.
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The Evaluation of the Reactivating and Neuroprotective Efficacy of Two Newly Prepared Bispyridinium Oximes (K305, K307) in Tabun-Poisoned Rats-A Comparison with Trimedoxime and the Oxime K203. Molecules 2017; 22:molecules22071152. [PMID: 28696367 PMCID: PMC6152392 DOI: 10.3390/molecules22071152] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 07/04/2017] [Accepted: 07/05/2017] [Indexed: 11/17/2022] Open
Abstract
The ability of two newly developed oximes (K305, K307) to protect tabun-poisoned rats from tabun-induced inhibition of brain acetylcholinesterase, acute neurotoxic signs and symptoms and brain damage was compared with that of the oxime K203 and trimedoxime. The reactivating and neuroprotective effects of the oximes studied combined with atropine on rats poisoned with tabun at a sublethal dose were evaluated. The reactivating efficacy of a newly developed oxime K305 is lower compared to the reactivating efficacy of the oxime K203 and trimedoxime while the ability of the oxime K307 to reactivate tabun-inhibited acetylcholinesterase (AChE) in the brain roughly corresponds to the reactivating efficacy of the oxime K203 and it is slightly lower compared to trimedoxime. In addition, only one newly developed oxime (K307) combined with atropine was able to markedly decrease tabun-induced neurotoxicity although it did not eliminate all tabun-induced acute neurotoxic signs and symptoms. These results correspond to the histopathological evaluation of tabun-induced brain damage. Therefore, the newly developed oximes are not suitable for the replacement of commonly used oximes (especially trimedoxime) in the treatment of acute tabun poisonings.
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Evaluation of soman-induced extracranial histopathology in the context of clinical biochemistry, mitotic and apoptotic activity and morphometric analysis. J Appl Biomed 2017. [DOI: 10.1016/j.jab.2016.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Abou-Donia MB, Siracuse B, Gupta N, Sobel Sokol A. Sarin (GB, O-isopropyl methylphosphonofluoridate) neurotoxicity: critical review. Crit Rev Toxicol 2016; 46:845-875. [PMID: 27705071 PMCID: PMC5764759 DOI: 10.1080/10408444.2016.1220916] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Sarin (GB, O-isopropyl methylphosphonofluoridate) is a potent organophosphorus (OP) nerve agent that inhibits acetylcholinesterase (AChE) irreversibly. The subsequent build-up of acetylcholine (ACh) in the central nervous system (CNS) provokes seizures and, at sufficient doses, centrally-mediated respiratory arrest. Accumulation of ACh at peripheral autonomic synapses leads to peripheral signs of intoxication and overstimulation of the muscarinic and nicotinic receptors, which is described as "cholinergic crisis" (i.e. diarrhea, sweating, salivation, miosis, bronchoconstriction). Exposure to high doses of sarin can result in tremors, seizures, and hypothermia. More seriously, build-up of ACh at neuromuscular junctions also can cause paralysis and ultimately peripherally-mediated respiratory arrest which can lead to death via respiratory failure. In addition to its primary action on the cholinergic system, sarin possesses other indirect effects. These involve the activation of several neurotransmitters including gamma-amino-butyric acid (GABA) and the alteration of other signaling systems such as ion channels, cell adhesion molecules, and inflammatory regulators. Sarin exposure is associated with symptoms of organophosphate-induced delayed neurotoxicity (OPIDN) and organophosphate-induced chronic neurotoxicity (OPICN). Moreover, sarin has been involved in toxic and immunotoxic effects as well as organophosphate-induced endocrine disruption (OPIED). The standard treatment for sarin-like nerve agent exposure is post-exposure injection of atropine, a muscarinic receptor antagonist, accompanied by an oxime, an AChE reactivator, and diazepam.
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Affiliation(s)
- Mohamed B Abou-Donia
- a Department of Pharmacology and Cancer Biology , Duke University , Durham , NC , USA
| | - Briana Siracuse
- a Department of Pharmacology and Cancer Biology , Duke University , Durham , NC , USA
| | - Natasha Gupta
- a Department of Pharmacology and Cancer Biology , Duke University , Durham , NC , USA
| | - Ashly Sobel Sokol
- a Department of Pharmacology and Cancer Biology , Duke University , Durham , NC , USA
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Lazar S, Egoz I, Brandeis R, Chapman S, Bloch-Shilderman E, Grauer E. Propagation of damage in the rat brain following sarin exposure: Differential progression of early processes. Toxicol Appl Pharmacol 2016; 310:87-97. [DOI: 10.1016/j.taap.2016.09.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/07/2016] [Accepted: 09/12/2016] [Indexed: 02/07/2023]
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Chronic Treatment with Naltrexone Prevents Memory Retention Deficits in Rats Poisoned with the Sarin Analog Diisopropylfluorophosphate (DFP) and Treated with Atropine and Pralidoxime. J Med Toxicol 2016; 11:433-8. [PMID: 25925946 DOI: 10.1007/s13181-015-0480-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Humans and rats poisoned with sarin develop chronic neurological disabilities that are not prevented with standardized antidotal therapy. We hypothesized that rats poisoned with the sarin analogue diisopropylfluorophosphate (DFP) and resuscitated with atropine and pralidoxime would have long-term memory deficits that were preventable with naltrexone treatment. Long Evans rats (250-275 g) were randomized to: DFP (N = 8): single subcutaneous (SC) injection of DFP (5 mg/kg). Treatment (N = 9): DFP (5 mg/kg) followed by chronic naltrexone (5 mg/kg/day × 12 weeks). Control (N = 12): single SC injection of isopropyl alcohol, (DFP vehicle) followed by chronic naltrexone (5 mg/kg/day). If toxicity developed after injection, antidotal therapy was initiated with atropine (2 mg/kg) and pralidoxime (25 mg/kg) and repeated as needed. After 12 weeks, rats underwent testing for place learning (acquisition) across 5 days of training using the Morris Water Maze. On day 6 a memory retention test was performed. Statistical analysis was performed using IBM SPSS Statistics. Rats receiving DFP rapidly developed toxicity requiring antidotal rescue. No differences in acquisition were seen between the DFP vs. DFP + naltrexone rats. During memory testing, DFP-poisoned rats spent significantly less time (29.4 ± 2.11 versus 38.5 ± 2.5 s, p < 0.05) and traveled less distance (267 ± 24.6 versus 370 ± 27.5 cm, p < 0.05) in the target quadrant compared to the treatment group. Treatment rats performed as well as control rats (p > 0.05) on the test for memory retention. Poisoning with DFP induced impaired memory retention. Deficits were not prevented by acute rescue with atropine and pralidoxime. Chronic naltrexone treatment led to preserved memory after DFP poisoning.
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Aroniadou-Anderjaska V, Figueiredo TH, Apland JP, Prager EM, Pidoplichko VI, Miller SL, Braga MFM. Long-term neuropathological and behavioral impairments after exposure to nerve agents. Ann N Y Acad Sci 2016; 1374:17-28. [PMID: 27002925 DOI: 10.1111/nyas.13028] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/15/2016] [Accepted: 01/25/2016] [Indexed: 01/11/2023]
Abstract
One of the deleterious effects of acute nerve agent exposure is the induction of status epilepticus (SE). If SE is not controlled effectively, it causes extensive brain damage. Here, we review the neuropathology observed after nerve agent-induced SE, as well as the ensuing pathophysiological, neurological, and behavioral alterations, with an emphasis on their time course and longevity. Limbic structures are particularly vulnerable to damage by nerve agent exposure. The basolateral amygdala (BLA), which appears to be a key site for seizure initiation upon exposure, suffers severe neuronal loss; however, GABAergic BLA interneurons display a delayed death, perhaps providing a window of opportunity for rescuing intervention. The end result is a long-term reduction of GABAergic activity in the BLA, with a concomitant increase in spontaneous excitatory activity; such pathophysiological alterations are not observed in the CA1 hippocampal area, despite the extensive neuronal loss. Hyperexcitability in the BLA may be at least in part responsible for the development of recurrent seizures and increased anxiety, while hippocampal damage may underlie the long-term memory impairments. Effective control of SE after nerve agent exposure, such that brain damage is also minimized, is paramount for preventing lasting neurological and behavioral deficits.
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Affiliation(s)
- Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Taiza H Figueiredo
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - James P Apland
- Neurotoxicology Branch, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Eric M Prager
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Volodymyr I Pidoplichko
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Steven L Miller
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Maria F M Braga
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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Chapman S, Yaakov G, Egoz I, Rabinovitz I, Raveh L, Kadar T, Gilat E, Grauer E. Sarin-induced brain damage in rats is attenuated by delayed administration of midazolam. Neurotoxicology 2015; 49:132-8. [PMID: 25976749 DOI: 10.1016/j.neuro.2015.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 04/28/2015] [Accepted: 05/02/2015] [Indexed: 01/27/2023]
Abstract
Sarin poisoned rats display a hyper-cholinergic activity including hypersalivation, tremors, seizures and death. Here we studied the time and dose effects of midazolam treatment following nerve agent exposure. Rats were exposed to sarin (1.2 LD50, 108 μg/kg, im), and treated 1 min later with TMB4 and atropine (TA 7.5 and 5 mg/kg, im, respectively). Midazolam was injected either at 1 min (1 mg/kg, im), or 1 h later (1 or 5 mg/kg i.m.). Cortical seizures were monitored by electrocorticogram (ECoG). At 5 weeks, rats were assessed in a water maze task, and then their brains were extracted for biochemical analysis and histological evaluation. Results revealed a time and dose dependent effects of midazolam treatment. Rats treated with TA only displayed acute signs of sarin intoxication, 29% died within 24h and the ECoG showed seizures for several hours. Animals that received midazolam within 1 min survived with only minor clinical signs but with no biochemical, behavioral, or histological sequel. Animals that lived to receive midazolam at 1h (87%) survived and the effects of the delayed administration were dose dependent. Midazolam 5 mg/kg significantly counteracted the acute signs of intoxication and the impaired behavioral performance, attenuated some of the inflammatory response with no effect on morphological damage. Midazolam 1mg/kg showed only a slight tendency to modulate the cognitive function. In addition, the delayed administration of both midazolam doses significantly attenuated ECoG compared to TA treatment only. These results suggest that following prolonged seizure, high dose midazolam is beneficial in counteracting adverse effects of sarin poisoning.
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Affiliation(s)
- Shira Chapman
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Guy Yaakov
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Inbal Egoz
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Ishai Rabinovitz
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Lily Raveh
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Tamar Kadar
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Eran Gilat
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Ettie Grauer
- Department of Pharmacology, Israel Institute for Biological Research, Ness Ziona, Israel.
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25
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Early brain magnetic resonance imaging can predict short and long-term outcomes after organophosphate poisoning in a rat model. Neurotoxicology 2015; 48:206-16. [DOI: 10.1016/j.neuro.2015.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 03/17/2015] [Accepted: 04/15/2015] [Indexed: 12/20/2022]
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26
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Kaur S, Singh S, Chahal KS, Prakash A. Potential pharmacological strategies for the improved treatment of organophosphate-induced neurotoxicity. Can J Physiol Pharmacol 2014; 92:893-911. [DOI: 10.1139/cjpp-2014-0113] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Organophosphates (OP) are highly toxic compounds that cause cholinergic neuronal excitotoxicity and dysfunction by irreversible inhibition of acetylcholinesterase, resulting in delayed brain damage. This delayed secondary neuronal destruction, which arises primarily in the cholinergic areas of the brain that contain dense accumulations of cholinergic neurons and the majority of cholinergic projection, could be largely responsible for persistent profound neuropsychiatric and neurological impairments such as memory, cognitive, mental, emotional, motor, and sensory deficits in the victims of OP poisoning. The therapeutic strategies for reducing neuronal brain damage must adopt a multifunctional approach to the various steps of brain deterioration: (i) standard treatment with atropine and related anticholinergic compounds; (ii) anti-excitotoxic therapies to prevent cerebral edema, blockage of calcium influx, inhibition of apoptosis, and allow for the control of seizure; (iii) neuroprotection by aid of antioxidants and N-methyl-d-aspartate (NMDA) antagonists (multifunctional drug therapy), to inhibit/limit the secondary neuronal damage; and (iv) therapies targeting chronic neuropsychiatric and neurological symptoms. These neuroprotective strategies may prevent secondary neuronal damage in both early and late stages of OP poisoning, and thus may be a beneficial approach to treating the neuropsychological and neuronal impairments resulting from OP toxicity.
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Affiliation(s)
- Shamsherjit Kaur
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
- Punjab Technical University, Kapurthala 144601, Punjab, India
| | - Satinderpal Singh
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| | - Karan Singh Chahal
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| | - Atish Prakash
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
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Kalász H, Nurulain SM, Veress G, Antus S, Darvas F, Adeghate E, Adem A, Hashemi F, Tekes K. Mini review on blood-brain barrier penetration of pyridinium aldoximes. J Appl Toxicol 2014; 35:116-23. [PMID: 25291712 DOI: 10.1002/jat.3048] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/14/2014] [Accepted: 06/16/2014] [Indexed: 01/27/2023]
Abstract
This paper reviews the blood-brain barrier (BBB) penetration of newly developed pyridinium aldoximes. Pyridinium aldoximes are highly charged hydrophilic compounds used in the treatment of subjects exposed to organophosphonates because they are effective as acetylcholinesterase reactivators. Pyridinium aldoximes have antidotal effects against poisoning with cholinesterase inhibitors, a frequent problem affecting people working with organophosphate-based insecticides and pesticides. Toxic organophosphonate products such as sarin and tabun can be used by terrorists as chemical warfare agents. This poses a severe challenge to all innocent and peace-loving people worldwide. This review gives a brief summary of BBB transporters and description of the current in vitro and in vivo methods for the characterization of BBB penetration of established and novel pyridinium aldoximes. The authors provide a putative mechanism of penetration, outline some future ways of formulation and discuss the possible advantages and disadvantages of increasing BBB penetration.
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Affiliation(s)
- H Kalász
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089, Budapest, Nagyvárad tér 4, Hungary; Department of Pharmacology and Therapeutics, CMHS, United Arab Emirates University, Al Ain, P.O.Box 17666, United Arab Emirates
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28
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Pereira EFR, Aracava Y, DeTolla LJ, Beecham EJ, Basinger GW, Wakayama EJ, Albuquerque EX. Animal models that best reproduce the clinical manifestations of human intoxication with organophosphorus compounds. J Pharmacol Exp Ther 2014; 350:313-21. [PMID: 24907067 DOI: 10.1124/jpet.114.214932] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The translational capacity of data generated in preclinical toxicological studies is contingent upon several factors, including the appropriateness of the animal model. The primary objectives of this article are: 1) to analyze the natural history of acute and delayed signs and symptoms that develop following an acute exposure of humans to organophosphorus (OP) compounds, with an emphasis on nerve agents; 2) to identify animal models of the clinical manifestations of human exposure to OPs; and 3) to review the mechanisms that contribute to the immediate and delayed OP neurotoxicity. As discussed in this study, clinical manifestations of an acute exposure of humans to OP compounds can be faithfully reproduced in rodents and nonhuman primates. These manifestations include an acute cholinergic crisis in addition to signs of neurotoxicity that develop long after the OP exposure, particularly chronic neurologic deficits consisting of anxiety-related behavior and cognitive deficits, structural brain damage, and increased slow electroencephalographic frequencies. Because guinea pigs and nonhuman primates, like humans, have low levels of circulating carboxylesterases-the enzymes that metabolize and inactivate OP compounds-they stand out as appropriate animal models for studies of OP intoxication. These are critical points for the development of safe and effective therapeutic interventions against OP poisoning because approval of such therapies by the Food and Drug Administration is likely to rely on the Animal Efficacy Rule, which allows exclusive use of animal data as evidence of the effectiveness of a drug against pathologic conditions that cannot be ethically or feasibly tested in humans.
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Affiliation(s)
- Edna F R Pereira
- Division of Translational Toxicology, Department of Epidemiology and Public Health (E.F.R.P., Y.A., E.X.A.), and Program of Comparative Medicine and Departments of Pathology, Medicine, and Epidemiology and Public Health (L.J.D.), University of Maryland School of Medicine, Baltimore, Maryland; Countervail Corporation, Charlotte, North Carolina (E.J.B., G.W.B.); and Biomedical Advanced Research and Development Authority and Office of the Assistant Secretary for Preparedness and Response, Department of Health and Human Services, Washington, DC (E.J.W.)
| | - Yasco Aracava
- Division of Translational Toxicology, Department of Epidemiology and Public Health (E.F.R.P., Y.A., E.X.A.), and Program of Comparative Medicine and Departments of Pathology, Medicine, and Epidemiology and Public Health (L.J.D.), University of Maryland School of Medicine, Baltimore, Maryland; Countervail Corporation, Charlotte, North Carolina (E.J.B., G.W.B.); and Biomedical Advanced Research and Development Authority and Office of the Assistant Secretary for Preparedness and Response, Department of Health and Human Services, Washington, DC (E.J.W.)
| | - Louis J DeTolla
- Division of Translational Toxicology, Department of Epidemiology and Public Health (E.F.R.P., Y.A., E.X.A.), and Program of Comparative Medicine and Departments of Pathology, Medicine, and Epidemiology and Public Health (L.J.D.), University of Maryland School of Medicine, Baltimore, Maryland; Countervail Corporation, Charlotte, North Carolina (E.J.B., G.W.B.); and Biomedical Advanced Research and Development Authority and Office of the Assistant Secretary for Preparedness and Response, Department of Health and Human Services, Washington, DC (E.J.W.)
| | - E Jeffrey Beecham
- Division of Translational Toxicology, Department of Epidemiology and Public Health (E.F.R.P., Y.A., E.X.A.), and Program of Comparative Medicine and Departments of Pathology, Medicine, and Epidemiology and Public Health (L.J.D.), University of Maryland School of Medicine, Baltimore, Maryland; Countervail Corporation, Charlotte, North Carolina (E.J.B., G.W.B.); and Biomedical Advanced Research and Development Authority and Office of the Assistant Secretary for Preparedness and Response, Department of Health and Human Services, Washington, DC (E.J.W.)
| | - G William Basinger
- Division of Translational Toxicology, Department of Epidemiology and Public Health (E.F.R.P., Y.A., E.X.A.), and Program of Comparative Medicine and Departments of Pathology, Medicine, and Epidemiology and Public Health (L.J.D.), University of Maryland School of Medicine, Baltimore, Maryland; Countervail Corporation, Charlotte, North Carolina (E.J.B., G.W.B.); and Biomedical Advanced Research and Development Authority and Office of the Assistant Secretary for Preparedness and Response, Department of Health and Human Services, Washington, DC (E.J.W.)
| | - Edgar J Wakayama
- Division of Translational Toxicology, Department of Epidemiology and Public Health (E.F.R.P., Y.A., E.X.A.), and Program of Comparative Medicine and Departments of Pathology, Medicine, and Epidemiology and Public Health (L.J.D.), University of Maryland School of Medicine, Baltimore, Maryland; Countervail Corporation, Charlotte, North Carolina (E.J.B., G.W.B.); and Biomedical Advanced Research and Development Authority and Office of the Assistant Secretary for Preparedness and Response, Department of Health and Human Services, Washington, DC (E.J.W.)
| | - Edson X Albuquerque
- Division of Translational Toxicology, Department of Epidemiology and Public Health (E.F.R.P., Y.A., E.X.A.), and Program of Comparative Medicine and Departments of Pathology, Medicine, and Epidemiology and Public Health (L.J.D.), University of Maryland School of Medicine, Baltimore, Maryland; Countervail Corporation, Charlotte, North Carolina (E.J.B., G.W.B.); and Biomedical Advanced Research and Development Authority and Office of the Assistant Secretary for Preparedness and Response, Department of Health and Human Services, Washington, DC (E.J.W.)
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A critical role of acute bronchoconstriction in the mortality associated with high-dose sarin inhalation: effects of epinephrine and oxygen therapies. Toxicol Appl Pharmacol 2013; 274:200-8. [PMID: 24269878 DOI: 10.1016/j.taap.2013.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/25/2013] [Accepted: 11/10/2013] [Indexed: 01/26/2023]
Abstract
Sarin is an organophosphate nerve agent that is among the most lethal chemical toxins known to mankind. Because of its vaporization properties and ease and low cost of production, sarin is the nerve agent with a strong potential for use by terrorists and rouge nations. The primary route of sarin exposure is through inhalation and, depending on the dose, sarin leads to acute respiratory failure and death. The mechanism(s) of sarin-induced respiratory failure is poorly understood. Sarin irreversibly inhibits acetylcholine esterase, leading to excessive synaptic levels of acetylcholine and, we have previously shown that sarin causes marked ventilatory changes including weakened response to hypoxia. We now show that LD50 sarin inhalation causes severe bronchoconstriction in rats, leading to airway resistance, increased hypoxia-induced factor-1α, and severe lung epithelium injury. Transferring animals into 60% oxygen chambers after sarin exposure improved the survival from about 50% to 75% at 24h; however, many animals died within hours after removal from the oxygen chambers. On the other hand, if LD50 sarin-exposed animals were administered the bronchodilator epinephrine, >90% of the animals survived. Moreover, while both epinephrine and oxygen treatments moderated cardiorespiratory parameters, the proinflammatory cytokine surge, and elevated expression of hypoxia-induced factor-1α, only epinephrine consistently reduced the sarin-induced bronchoconstriction. These data suggest that severe bronchoconstriction is a critical factor in the mortality induced by LD50 sarin inhalation, and epinephrine may limit the ventilatory, inflammatory, and lethal effects of sarin.
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Eisenkraft A, Falk A, Finkelstein A. The role of glutamate and the immune system in organophosphate-induced CNS damage. Neurotox Res 2013; 24:265-79. [PMID: 23532600 DOI: 10.1007/s12640-013-9388-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 03/10/2013] [Accepted: 03/15/2013] [Indexed: 12/12/2022]
Abstract
Organophosphate (OP) poisoning is associated with long-lasting neurological damage, which is attributed mainly to the excessive levels of glutamate caused by the intoxication. Glutamate toxicity, however, is not specific to OP poisoning, and is linked to propagation of damage in both acute and chronic neurodegenerative conditions in the central nervous system (CNS). In addition to acute excitotoxic effects of glutamate, there is now a growing amount of evidence of its intricate immunomodulatory effects in the brain, involving both the innate and the adaptive immune systems. Moreover, it was demonstrated that immunomodulatory treatments, aimed at regulating the interaction between the resident immune cells of the brain (microglia) and the peripheral immune system, can support buffering of excessive levels of glutamate and restoration of the homeostasis. In this review, we will discuss the role of glutamate as an excitotoxic agent in the acute phase of OP poisoning, and the possible functions it may have as both a neuroprotectant and an immunomodulator in the sub-acute and chronic phases of OP poisoning. In addition, we will describe the novel immune-based neuroprotective strategies aimed at counteracting the long-term neurodegenerative effects of glutamate in the CNS.
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31
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Jett DA. Chemical toxins that cause seizures. Neurotoxicology 2012; 33:1473-1475. [PMID: 23085523 DOI: 10.1016/j.neuro.2012.10.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 10/09/2012] [Accepted: 10/09/2012] [Indexed: 10/27/2022]
Abstract
Seizurogenic chemicals include a variety of toxic agents, including chemical warfare agents, toxic industrial chemicals, and natural toxins. Chemical weapons such as sarin and VX, and pesticides such as parathion and carbaryl cause hyperstimulation of cholinergic receptors and an increase in excitatory neurotransmission. Glutamatergic hyperstimulation can occur after exposure to excitatory amino acid toxins such as the marine toxin domoic acid. Other pesticides such as lindane and strychnine do not affect excitatory neurotransmission directly, but rather, they block the inhibitory regulation of neurotransmission by antagonism of inhibitory GABA and glycine synapses. In this paper, chemicals that cause seizures by a variety of molecular mechanisms and pathways are discussed.
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Affiliation(s)
- David A Jett
- National Institutes of Health, NINDS, 6001 Executive Blvd. NSC, Room 2177, MSC 9527, Bethesda, MD 20892-9527, United States.
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32
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Magnesium sulfate treatment against sarin poisoning: dissociation between overt convulsions and recorded cortical seizure activity. Arch Toxicol 2012; 87:347-60. [DOI: 10.1007/s00204-012-0916-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 07/24/2012] [Indexed: 10/27/2022]
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33
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Chen Y. Organophosphate-induced brain damage: mechanisms, neuropsychiatric and neurological consequences, and potential therapeutic strategies. Neurotoxicology 2012; 33:391-400. [PMID: 22498093 DOI: 10.1016/j.neuro.2012.03.011] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/24/2012] [Accepted: 03/25/2012] [Indexed: 02/06/2023]
Abstract
Organophosphate (OP)-induced brain damage is defined as progressive damage to the brain, resulting from the cholinergic neuronal excitotoxicity and dysfunction induced by OP-induced irreversible AChE inhibition. This delayed secondary neuronal damage that occurs mainly in the cholinergic regions of the brain that contain dense accumulations of cholinergic neurons and the majority of cholinergic projection, might be largely responsible for persistent profound neuropsychiatric and neurological impairments (memory, cognitive, mental, emotional, motor and sensory deficits) in the victims of OP poisoning. Neuroprotective strategies for attenuating OP-induced brain damage should target different development stages of OP-induced brain damage, and may include but not limited to: (1) Antidote therapies with atropine and related efficient anticholinergic drugs; (2) Anti-excitotoxic therapies targeting attenuation of cerebral edema and inflammatory reaction, blockage of calcium influx, inhibition of apoptosis program, and the control of seizures; (3) Neuroprotective strategies using cytokines, antioxidants and NMDAR antagonists (a single drug or a combination of drugs) to slow down the process of secondary neuronal damage; and (4) Therapies targeting individual symptoms or clusters of chronic neuropsychiatric and neurological symptoms. These neuroprotective strategies may help limit or prevent secondary neuronal damage at the early stage of OP poisoning and attenuate the subsequent neuropsychiatric and neurological impairments, thus reducing the long-term disability caused by exposure to OPs.
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Affiliation(s)
- Yun Chen
- BrightstarTech, Inc., 23102 Meadow Mist Road, Clarksburg, MD 20871, USA.
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34
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Shrot S, Anaby D, Krivoy A, Makarovsky I, Rosman Y, Bloch-Shilderman E, Lazar S, Bar-Shir A, Cohen Y. Early in vivo MR spectroscopy findings in organophosphate-induced brain damage-potential biomarkers for short-term survival. Magn Reson Med 2012; 68:1390-8. [PMID: 22247007 DOI: 10.1002/mrm.24155] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 12/07/2011] [Accepted: 12/15/2011] [Indexed: 11/08/2022]
Abstract
Organophosphates are highly toxic substances, which cause severe brain damage. The hallmark of the brain injury is major convulsions. The goal of this study was to assess the spatial and temporal MR changes in the brain of paraoxon intoxicated rats. T2-weighted MRI and ¹H-MR-spectroscopy were conducted before intoxication, 3 h, 24 h, and 8 days postintoxication. T2 prolongation mainly in the thalami and cortex was evident as early as 3 h after intoxication (4-6% increase in T2 values, P < 0.05). On spectroscopy, N-acetyl aspartate (NAA)/creatine and NAA/choline levels significantly decreased 3 h postintoxication (>20% decrease, P < 0.005), and 3 h lactate peak was evident in all intoxicated animals. On the 8th day, although very little T2 changes were evident, NAA/creatine and choline/creatine were significantly decreased (>15%, P < 0.05). Animals who succumbed had extensive cortical edema, significant higher lactate levels and a significant decrease in NAA/creatine and NAA/choline levels compared to animals which survived the experiment. Organophosphates-induced brain damage is obvious on MR data already 3 h postintoxication. In vivo spectroscopic changes are more sensitive for assessing long-term injury than T2-weighted MR imaging. Early spectroscopic findings might be used as biomarkers for the severity of the intoxication and might predict early survival.
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Affiliation(s)
- Shai Shrot
- Chemical, Biological and Nuclear Medicine Branch, Medical Corps, IDF, Tel-Hashomer Military Base, Israel.
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35
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Cho Y, Kim WS, Hur GH, Ha YC. Minimum effective drug concentrations of a transdermal patch system containing procyclidine and physostigmine for prophylaxis against soman poisoning in rhesus monkeys. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2012; 33:1-8. [PMID: 22051905 DOI: 10.1016/j.etap.2011.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 08/25/2011] [Accepted: 10/07/2011] [Indexed: 05/31/2023]
Abstract
A transdermal patch system containing procyclidine, an N-methyl-d-aspartate receptor antagonist possessing anticholinergic action, and physostigmine, a reversible cholinesterase inhibitor, was developed, and its prophylactic efficacy against soman intoxication was investigated. Male rhesus monkeys were shaved on the dorsal area, attached with a matrix-type patch with various sizes (2×2 to 7×7 cm) for 24 or 72 h, and challenged with 2×LD₅₀ doses (13μg/kg) of soman. The smallest patch size for the protection against lethality induced by soman intoxication was 3×3cm, resulting in blood procyclidine concentration of 10.8 ng/ml, blood physostigmine concentration of 0.54 ng/ml, which are much lower concentrations than maximum sign-free doses, and blood cholinesterase inhibition of 42%. The drug concentrations and enzyme inhibition rate corresponding to a diverging point of survivability were presumably estimated to be around 7 ng/ml for procyclidine, 0.35 ng/ml for physostigmine, and 37% of enzyme inhibition. Separately, in combination with the patch treatment, the post treatment consisting of atropine (0.5 mg/kg) plus 1-[([4-(aminocarbonyl)pyridinio]methoxy)methyl]-2-[(hydroxyimino)methyl]pyridinium (HI-6, 50 mg/kg) exerted protection against 5×LD₅₀ challenge of soman, which means the posttreatment remarkably augmented the efficacy of the patch. Additionally, it was found that brain injuries induced by soman toxicity were effectively prevented by the patch treatment according to histopathological examinations. These results suggest that the patch system could be an effective alternative for diazepam, an anticonvulsant, and the current pyridostigmine pretreatment, and especially in combination with atropine plus HI-6, could be a choice for quality survival from nerve-agent poisoning.
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Affiliation(s)
- Young Cho
- Chemical Biological Defense Research Division, 5th R&D Center (5-4), Agency for Defense Development, Yuseong P.O. Box 35, Taejon 305-600, Republic of Korea.
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Abstract
Bioterrorism is defined as the intentional use of biological, chemical, nuclear, or radiological agents to cause disease, death, or environmental damage. Early recognition of a bioterrorist attack is of utmost importance to minimize casualties and initiate appropriate therapy. The range of agents that could potentially be used as weapons is wide, however, only a few of these agents have all the characteristics making them ideal for that purpose. Many of the chemical and biological weapons can cause neurological symptoms and damage the nervous system in varying degrees. Therefore, preparedness among neurologists is important. The main challenge is to be cognizant of the clinical syndromes and to be able to differentiate diseases caused by bioterrorism from naturally occurring disorders. This review provides an overview of the biological and chemical warfare agents, with a focus on neurological manifestation and an approach to treatment from a perspective of neurological critical care.
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Affiliation(s)
- Katharina M Busl
- Department of Neurological Sciences, Rush Medical College, Rush University Medical Center, Chicago, IL 60612, USA.
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Langston JL, Wright LKM, Connis N, Lumley LA. Characterizing the behavioral effects of nerve agent-induced seizure activity in rats: increased startle reactivity and perseverative behavior. Pharmacol Biochem Behav 2011; 100:382-91. [PMID: 21983492 DOI: 10.1016/j.pbb.2011.09.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/21/2011] [Accepted: 09/24/2011] [Indexed: 11/27/2022]
Abstract
The development and deployment of next-generation therapeutics to protect military and civilian personnel against chemical warfare nerve agent threats require the establishment and validation of animal models. The purpose of the present investigation was to characterize the behavioral consequences of soman (GD)-induced seizure activity using a series of behavioral assessments. Male Sprague-Dawley rats (n=24), implanted with a transmitter for telemetric recording of encephalographic signals, were administered either saline or 1.0 LD₅₀ GD (110 μg/kg, sc) followed by treatment with a combination of atropine sulfate (2 mg/kg, im) and the oxime HI-6 (93.6 mg/kg, im) at 1 min post-exposure. Seizure activity was allowed to continue for 30 min before administration of the anticonvulsant diazepam (10 mg/kg, sc). The animals that received GD and experienced seizure activity had elevated startle responses to both 100- and 120-dB startle stimuli compared to control animals. The GD-exposed animals that had seizure activity also exhibited diminished prepulse inhibition in response to 120-dB startle stimuli, indicating altered sensorimotor gating. The animals were subsequently evaluated for the acquisition of lever pressing using an autoshaping procedure. Animals that experienced seizure activity engaged in more goal-directed (i.e., head entries into the food trough) behavior than did control animals. There were, however, no differences between groups in the number of lever presses made during 15 sessions of autoshaping. Finally, the animals were evaluated for the development of fixed-ratio (FR) schedule performance. Animals that experienced GD-induced seizure activity engaged in perseverative food trough-directed behaviors. There were few differences between groups on other measures of FR schedule-controlled behavior. It is concluded that the GD-induced seizure activity increased startle reactivity and engendered perseverative responding and that these measures are useful for assessing the long-term effects of GD exposure in rats.
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Affiliation(s)
- Jeffrey L Langston
- US Army Medical Research Institute of Chemical Defense, Analytical Toxicology Division, Neurobehavioral Toxicology Branch, Aberdeen Proving Ground, MD 21010-5400, USA
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Apland JP, Figueiredo TH, Qashu F, Aroniadou-Anderjaska V, Souza AP, Braga MFM. Higher susceptibility of the ventral versus the dorsal hippocampus and the posteroventral versus anterodorsal amygdala to soman-induced neuropathology. Neurotoxicology 2010; 31:485-92. [PMID: 20570628 PMCID: PMC2933957 DOI: 10.1016/j.neuro.2010.05.014] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 04/09/2010] [Accepted: 05/31/2010] [Indexed: 10/19/2022]
Abstract
Nerve agents are acetylcholinesterase inhibitors, exposure to which causes brain damage, primarily by inducing intense seizure activity. Knowledge of the brain regions that are most vulnerable to nerve agent-induced brain damage can facilitate the development of drugs targeting the protection of these regions. Both the amygdala and the hippocampus have been shown to suffer significant damage after nerve agent exposure, but the amygdala appears to be the more severely affected structure. However, damage in the amygdala has generally been compared with damage in the dorsal hippocampus, whereas there is evidence that the ventral hippocampus is significantly more susceptible to seizures than the dorsal region and, therefore, it may also be more susceptible to nerve agent-induced neuropathology. Here, we report that after status epilepticus induced by soman administration to rats, neuronal degeneration as assessed by Fluoro-Jade C staining was more extensive in the ventral than the dorsal hippocampal subfields, 1 day after soman exposure. Seven days later, the difference between dorsal and ventral regions was not statistically significant. In the amygdala, soman-induced neurodegeneration was more severe in the posteroventral regions of the lateral, basolateral, and medial nuclei compared to the anterodorsal regions of these nuclei. In contrast, the basomedial nucleus was more severely affected in the anterodorsal region. The extent of neurodegeneration in the amygdala was not significantly different from that in the ventral hippocampus. However, when compared with the whole hippocampus, the amygdala displayed more severe neurodegeneration, on both day 1 and day 7 after soman exposure. Testing the protective efficacy of drugs against nerve agent-induced brain damage should include examination of the ventral hippocampus and the posteroventral regions of the amygdala, as these areas are most vulnerable to nerve agent-induced neurodegeneration.
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Affiliation(s)
- James P. Apland
- U.S. Army Medical Research Institute of Chemical Defense, Neurobehavioral Toxicology Branch, Aberdeen Proving Ground, MD, 21010
| | - Taiza H. Figueiredo
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Felicia Qashu
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Adriana P. Souza
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Maria F. M. Braga
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
- Department of Psychiatry, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
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39
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A murine model for sarin exposure using the carboxylesterase inhibitor CBDP. Neurotoxicology 2010; 31:502-8. [DOI: 10.1016/j.neuro.2010.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 03/25/2010] [Accepted: 05/17/2010] [Indexed: 11/20/2022]
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Pope C, Mechoulam R, Parsons L. Endocannabinoid signaling in neurotoxicity and neuroprotection. Neurotoxicology 2010; 31:562-71. [PMID: 19969019 PMCID: PMC2891218 DOI: 10.1016/j.neuro.2009.12.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 12/02/2009] [Indexed: 01/23/2023]
Abstract
The cannabis plant and products produced from it, such as marijuana and hashish, have been used for centuries for their psychoactive properties. The mechanism for how Delta(9)-tetrahydrocannabinol (THC), the active constituent of cannabis, elicits these neurological effects remained elusive until relatively recently, when specific G-protein coupled receptors were discovered that appeared to mediate cellular actions of THC. Shortly after discovery of these specific receptors, endogenous ligands (endocannabinoids) were identified. Since that time, an extensive number of papers have been published on the endocannabinoid signaling system, a widespread neuromodulatory mechanism that influences neurotransmission throughout the nervous system. This paper summarizes presentations given at the 12th International Neurotoxicology Association meeting that described the potential role of endocannabinoids in the expression of neurotoxicity. Dr. Raphael Mechoulam first gave an overview of the discovery of exogenous and endogenous cannabinoids and their potential for neuroprotection in a variety of conditions. Dr. Larry Parsons then described studies suggesting that endocannabinoid signaling may play a selective role in drug reinforcement. Dr. Carey Pope presented information on the role that endocannabinoid signaling may have in the expression of cholinergic toxicity following anticholinesterase exposures. Together, these presentations highlighted the diverse types of neurological insults that may be modulated by endocannabinoids and drugs/toxicants which might influence endocannabinoid signaling pathways.
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Affiliation(s)
- C Pope
- Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, USA.
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41
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Angoa-Pérez M, Kreipke CW, Thomas DM, Van Shura KE, Lyman M, McDonough JH, Kuhn DM. Soman increases neuronal COX-2 levels: possible link between seizures and protracted neuronal damage. Neurotoxicology 2010; 31:738-46. [PMID: 20600289 DOI: 10.1016/j.neuro.2010.06.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 06/10/2010] [Accepted: 06/20/2010] [Indexed: 01/27/2023]
Abstract
Nerve agent-induced seizures cause neuronal damage in brain limbic and cortical circuits leading to persistent behavioral and cognitive deficits. Without aggressive anticholinergic and benzodiazepine therapy, seizures can be prolonged and neuronal damage progresses for extended periods of time. The objective of this study was to determine the effects of the nerve agent soman on expression of cyclooxygenase-2 (COX-2), the initial enzyme in the biosynthetic pathway of the proinflammatory prostaglandins and a factor that has been implicated in seizure initiation and propagation. Rats were exposed to a toxic dose of soman and scored behaviorally for seizure intensity. Expression of COX-2 was determined throughout brain from 4h to 7 days after exposure by immunohistochemistry and immunoblotting. Microglial activation and astrogliosis were assessed microscopically over the same time-course. Soman increased COX-2 expression in brain regions known to be damaged by nerve agents (e.g., hippocampus, amygdala, piriform cortex and thalamus). COX-2 expression was induced in neurons, and not in microglia or astrocytes, and remained elevated through 7 days. The magnitude of COX-2 induction was correlated with seizure intensity. COX-1 expression was not changed by soman. Increased expression of neuronal COX-2 by soman is a late-developing response relative to other signs of acute physiological distress caused by nerve agents. COX-2-mediated production of prostaglandins is a consequence of the seizure-induced neuronal damage, even after survival of the initial cholinergic crisis is assured. COX-2 inhibitors should be considered as adjunct therapy in nerve agent poisoning to minimize nerve agent-induced seizure activity.
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Affiliation(s)
- Mariana Angoa-Pérez
- Research & Development Service, John D. Dingell VA Medical Center, Detroit, MI, USA
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Aroniadou-Anderjaska V, Figueiredo TH, Apland JP, Qashu F, Braga MFM. Primary brain targets of nerve agents: the role of the amygdala in comparison to the hippocampus. Neurotoxicology 2009; 30:772-6. [PMID: 19591865 PMCID: PMC2761531 DOI: 10.1016/j.neuro.2009.06.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/20/2009] [Accepted: 06/30/2009] [Indexed: 12/01/2022]
Abstract
Exposure to nerve agents and other organophosphorus acetylcholinesterases used in industry and agriculture can cause death, or brain damage, producing long-term cognitive and behavioral deficits. Brain damage is primarily caused by the intense seizure activity induced by these agents. Identifying the brain regions that respond most intensely to nerve agents, in terms of generating and spreading seizure activity, along with knowledge of the physiology and biochemistry of these regions, can facilitate the development of pharmacological treatments that will effectively control seizures even if administered when seizures are well underway. Here, we contrast the pathological (neuronal damage) and pathophysiological (neuronal activity) findings of responses to nerve agents in the amygdala and the hippocampus, the two brain structures that play a central role in the generation and spread of seizures. The evidence so far suggests that exposure to nerve agents causes significantly more damage in the amygdala than in the hippocampus. Furthermore, in in vitro brain slices, the amygdala generates prolonged, seizure-like neuronal discharges in response to the nerve agent soman, at a time when the hippocampus generates only interictal-like activity. In vivo experiments are now required to confirm the primary role that the amygdala seems to play in nerve agent-induced seizure generation.
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Affiliation(s)
- Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of Health Sciences, Bethesda, MD 20814, USA
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43
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Bansal I, Waghmare CK, Anand T, Gupta AK, Bhattacharya BK. Differential mRNA expression of acetylcholinesterase in the central nervous system of rats with acute and chronic exposure of sarin & physostigmine. J Appl Toxicol 2009; 29:386-94. [DOI: 10.1002/jat.1424] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Pachiappan A, Thwin MM, Weng Keong L, Lee FK, Manikandan J, Sivakumar V, Gopalakrishnakone P. ETS2 Regulating Neurodegenerative Signaling Pathway of Human Neuronal (SH-SY5Y) Cells Exposed to Single and Repeated Low-Dose Sarin (GB). Chem Res Toxicol 2009; 22:990-6. [DOI: 10.1021/tx8003467] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arjunan Pachiappan
- Departments of Anatomy and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, DSO National Laboratories, Singapore 118230, and Porter Neuroscience Research Center, National Institutes of Health, Bethesda, Maryland 20892
| | - Maung Maung Thwin
- Departments of Anatomy and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, DSO National Laboratories, Singapore 118230, and Porter Neuroscience Research Center, National Institutes of Health, Bethesda, Maryland 20892
| | - Loke Weng Keong
- Departments of Anatomy and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, DSO National Laboratories, Singapore 118230, and Porter Neuroscience Research Center, National Institutes of Health, Bethesda, Maryland 20892
| | - Fook Kay Lee
- Departments of Anatomy and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, DSO National Laboratories, Singapore 118230, and Porter Neuroscience Research Center, National Institutes of Health, Bethesda, Maryland 20892
| | - Jayapal Manikandan
- Departments of Anatomy and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, DSO National Laboratories, Singapore 118230, and Porter Neuroscience Research Center, National Institutes of Health, Bethesda, Maryland 20892
| | - Viswanathan Sivakumar
- Departments of Anatomy and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, DSO National Laboratories, Singapore 118230, and Porter Neuroscience Research Center, National Institutes of Health, Bethesda, Maryland 20892
| | - Ponnampalam Gopalakrishnakone
- Departments of Anatomy and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, DSO National Laboratories, Singapore 118230, and Porter Neuroscience Research Center, National Institutes of Health, Bethesda, Maryland 20892
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Joosen MJ, Jousma E, van den Boom TM, Kuijpers WC, Smit AB, Lucassen PJ, van Helden HP. Long-term cognitive deficits accompanied by reduced neurogenesis after soman poisoning. Neurotoxicology 2009; 30:72-80. [DOI: 10.1016/j.neuro.2008.11.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 11/12/2008] [Accepted: 11/24/2008] [Indexed: 01/13/2023]
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46
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Apland JP, Aroniadou-Anderjaska V, Braga MFM. Soman induces ictogenesis in the amygdala and interictal activity in the hippocampus that are blocked by a GluR5 kainate receptor antagonist in vitro. Neuroscience 2008; 159:380-9. [PMID: 19136046 DOI: 10.1016/j.neuroscience.2008.11.053] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 11/07/2008] [Accepted: 11/26/2008] [Indexed: 10/21/2022]
Abstract
Exposure to organophosphorus nerve agents induces brain seizures, which can cause profound brain damage resulting in death or long-term cognitive deficits. The amygdala and the hippocampus are two of the most seizure-prone brain structures, but their relative contribution to the generation of seizures after nerve agent exposure is unclear. Here, we report that application of 1 muM soman for 30 min, in rat coronal brain slices containing both the hippocampus and the amygdala, produces prolonged synchronous neuronal discharges (10-40 s duration, 1.5-5 min interval of occurrence) resembling ictal activity in the basolateral nucleus of the amygdala (BLA), but only interictal-like activity ("spikes" of 100-250 ms duration; 2-5 s interval) in the pyramidal cell layer of the CA1 hippocampal area. BLA ictal- and CA1 interictal-like activity were synaptically driven, as they were blocked by the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione. As the expression of the GluR5 subunit of kainate receptors is high in the amygdala, and kainate receptors containing this subunit (GluR5KRs) play an important role in the regulation of neuronal excitability in both the amygdala and the hippocampus, we tested the efficacy of a GluR5KR antagonist against the epileptiform activity induced by soman. The GluR5KR antagonist UBP302 reduced the amplitude of the hippocampal interictal-like spikes, and eliminated the seizure-like discharges in the BLA, or reduced their duration and frequency, with no significant effect on the evoked field potentials. This is the first study reporting in vitro ictal-like activity in response to a nerve agent. Our findings, along with previous literature, suggest that the amygdala may play a more important role than the hippocampus in the generation of seizures following soman exposure, and provide the first evidence that GluR5KR antagonists may be an effective treatment against nerve agent-induced seizures.
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Affiliation(s)
- J P Apland
- Neurotoxicology Branch, USAMRICD, Aberdeen Proving Ground (EA), MD 21010, USA
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47
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Long-term consequences of soman poisoning in mice: part 2. Emotional behavior. Behav Brain Res 2008; 191:95-103. [PMID: 18457884 DOI: 10.1016/j.bbr.2008.03.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 03/14/2008] [Accepted: 03/16/2008] [Indexed: 11/24/2022]
Abstract
The organophosphorus compound soman produces long-lasting epileptic seizure activity which is associated to brain damage, more particularly in the hippocampus and the amygdala. The companion paper (see part 1 in the same journal issue) describes the neuropathology in the amygdala of soman-poisoned mice. The present paper examines the long-term effects of soman poisoning on emotional reactivity in mice, 30 or 90 days after intoxication using behavioral tasks involving amygdala function. The emotional behavior was estimated in animal tests of unconditioned fear (light/dark boxes, elevated plus-maze) and conditioned fear (auditory and contextual response). In the light/dark boxes and elevated plus-maze, mice intoxicated with soman (110 microg/kg, 1.2 LD(50)) showed an anxiety-like behavior profile at post-poisoning days 30 and 90. In conditioned fear, results showed that both auditory and contextual conditioned responses are increased on post-soman day 30 but no longer on post-soman day 90, evidencing behavioral recovery overtime. This latter behavioral result is in accordance with the delayed neuronal regeneration patterns described in the companion paper (part 1).
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48
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Grauer E, Chapman S, Rabinovitz I, Raveh L, Weissman BA, Kadar T, Allon N. Single whole-body exposure to sarin vapor in rats: Long-term neuronal and behavioral deficits. Toxicol Appl Pharmacol 2008; 227:265-74. [DOI: 10.1016/j.taap.2007.11.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Revised: 10/29/2007] [Accepted: 11/07/2007] [Indexed: 11/24/2022]
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49
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Dassanayake T, Weerasinghe V, Dangahadeniya U, Kularatne K, Dawson A, Karalliedde L, Senanayake N. Long-term event-related potential changes following organophosphorus insecticide poisoning. Clin Neurophysiol 2008; 119:144-50. [PMID: 18042425 PMCID: PMC3145126 DOI: 10.1016/j.clinph.2007.09.134] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 09/17/2007] [Accepted: 09/24/2007] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To determine prolonged effects of organophosphorus (OP) insecticide poisoning on cognitive event-related potentials (ERPs). METHODS ERPs of a group of 32 patients recovered from cholinergic phase of OP insecticide poisoning were compared with those of two matched control groups: 32 healthy volunteers and nine patients hospitalised with paracetamol overdose. A follow-up assessment was done in 21 patients (66% of the initial sample) 6 months after OP intoxication and the findings were compared with their initial ERP data. RESULTS Patients showed highly significant prolongation of P300 latency, compared to healthy controls (p=0.003) and the controls with paracetamol overdose (p=0.016). Follow-up ERP findings of the patients revealed that this impairment remained unchanged even 6 months after OP poisoning (p=0.790). There was no significant difference in N100, P200 and N200 latencies or P300 amplitude either among the groups or between the two assessments of the patients with OP poisoning. CONCLUSIONS Our results suggest that acute OP poisoning causes a delay in cognitive processes involved in stimulus classification, lasting at least for 6 months. SIGNIFICANCE These findings highlight the possibility of development of long-lasting cognitive deficits following OP insecticide poisoning, and warrant longer-term prospective studies to determine whether this impairment is permanent.
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Affiliation(s)
- T Dassanayake
- Department of Physiology, Faculty of Medicine, Peradeniya 20400, Sri Lanka.
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50
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Oxotremorine-induced hypothermia as a method for evaluating long-term neuronal changes following poisoning by cholinesterase inhibitors in rats. Toxicology 2007; 242:1-6. [DOI: 10.1016/j.tox.2007.08.097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 08/28/2007] [Accepted: 08/30/2007] [Indexed: 11/22/2022]
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