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Guignet M, Vuong J, Martinez A, Ballapapinan T, White HS. Temporal relationship between levetiracetam nonadherence and breakthrough seizures in a preclinical model of temporal lobe epilepsy. Epilepsia 2024; 65:497-510. [PMID: 38031477 DOI: 10.1111/epi.17835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/21/2023] [Accepted: 11/27/2023] [Indexed: 12/01/2023]
Abstract
OBJECTIVE Poor medication adherence remains a concern for individuals managing their epilepsy with antiseizure medicines (ASMs); however, ethical concerns around withholding medication make it impossible to study the causal relationship between missed doses and seizures in patients. Previous preclinical studies from our group suggest that mechanistically distinct ASMs have varying degrees of forgiveness when a dose is missed. However, with only a few ASMs studied in the context of nonadherence, we sought to expand on previous work to understand the relationship between levetiracetam (LEV) nonadherence and breakthrough seizures. METHODS Chronic oral dosing was initiated in rats with established epilepsy via our automated medication-in-food delivery system coupled to 24/7 video-electroencephalographic recording. Baseline seizure burden was established for 4 weeks before enrolling subjects into a 4-week treatment period with LEV in a 100% fully adherent (75 mg/kg four times daily) or 50% variably adherent paradigm. The temporal relationship between missed doses and breakthrough seizures was correlated with LEV plasma and brain concentrations in separate cohorts of animals. RESULTS Full adherence to LEV significantly improved seizure control by 50% in half of the animals. Poor adherence worsened seizure frequency by 85%, with most rats having more severe seizures that formed in clusters following missed doses. LEV concentrations remained below therapeutic levels (<10 μg/mL) in nonadherent animals, with brain and plasma levels directly correlating with the degree of adherence in a 24-h period. Missed doses of LEV immediately increased the risk of breakthrough seizures; however, this risk was significantly reduced with improved adherence in a 24-h period. SIGNIFICANCE These findings enhance our understanding of ASM nonadherence in preclinical models, highlighting that the timing of missed doses and their impact on seizures may vary between different ASMs. Notably, LEV demonstrates a robust pharmacokinetic reliance on missed doses leading to breakthrough seizures.
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Affiliation(s)
- Michelle Guignet
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Jonathan Vuong
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Alejandra Martinez
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Ticha Ballapapinan
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, USA
| | - H Steve White
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, USA
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Sandouka S, Singh PK, Saadi A, Taiwo RO, Sheeni Y, Zhang T, Deeb L, Guignet M, White SH, Shekh-Ahmad T. Repurposing dimethyl fumarate as an antiepileptogenic and disease-modifying treatment for drug-resistant epilepsy. J Transl Med 2023; 21:796. [PMID: 37940957 PMCID: PMC10634153 DOI: 10.1186/s12967-023-04695-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 11/02/2023] [Indexed: 11/10/2023] Open
Abstract
BACKGROUND Epilepsy affects over 65 million people worldwide and significantly burdens patients, caregivers, and society. Drug-resistant epilepsy occurs in approximately 30% of patients and growing evidence indicates that oxidative stress contributes to the development of such epilepsies. Activation of the Nrf2 pathway, which is involved in cellular defense, offers a potential strategy for reducing oxidative stress and epilepsy treatment. Dimethyl fumarate (DMF), an Nrf2 activator, exhibits antioxidant and anti-inflammatory effects and is used to treat multiple sclerosis. METHODS The expression of Nrf2 and its related genes in vehicle or DMF treated rats were determined via RT-PCR and Western blot analysis. Neuronal cell death was evaluated by immunohistochemical staining. The effects of DMF in preventing the onset of epilepsy and modifying the disease were investigated in the kainic acid-induced status epilepticus model of temporal lobe epilepsy in rats. The open field, elevated plus maze and T-Maze spontaneous alteration tests were used for behavioral assessments. RESULTS We demonstrate that administration of DMF following status epilepticus increased Nrf2 activity, attenuated status epilepticus-induced neuronal cell death, and decreased seizure frequency and the total number of seizures compared to vehicle-treated animals. Moreover, DMF treatment reversed epilepsy-induced behavioral deficits in the treated rats. Moreover, DMF treatment even when initiated well after the diagnosis of epilepsy, reduced symptomatic seizures long after the drug was eliminated from the body. CONCLUSIONS Taken together, these findings suggest that DMF, through the activation of Nrf2, has the potential to serve as a therapeutic target for preventing epileptogenesis and modifying epilepsy.
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Affiliation(s)
- Sereen Sandouka
- Faculty of Medicine, The School of Pharmacy, The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Prince Kumar Singh
- Faculty of Medicine, The School of Pharmacy, The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Aseel Saadi
- Faculty of Medicine, The School of Pharmacy, The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rhoda Olowe Taiwo
- Faculty of Medicine, The School of Pharmacy, The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yara Sheeni
- Faculty of Medicine, The School of Pharmacy, The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Taige Zhang
- Faculty of Medicine, The School of Pharmacy, The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Larin Deeb
- Faculty of Medicine, The School of Pharmacy, The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Michelle Guignet
- Department of Pharmacy, Center for Epilepsy Drug Discovery, University of Washington, Seattle, WA, USA
| | - Steve H White
- Department of Pharmacy, Center for Epilepsy Drug Discovery, University of Washington, Seattle, WA, USA
| | - Tawfeeq Shekh-Ahmad
- Faculty of Medicine, The School of Pharmacy, The Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel.
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Guignet M, Campbell A, Vuong J, Whittington D, White HS. Perampanel's forgiveness factor in a variable medication adherence paradigm in a rat model of chronic epilepsy. J Transl Med 2023; 21:642. [PMID: 37730661 PMCID: PMC10510183 DOI: 10.1186/s12967-023-04490-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/30/2023] [Indexed: 09/22/2023] Open
Abstract
BACKGROUND Poor medication adherence contributes to increased morbidity and mortality in patients with epilepsy and may be under-addressed in clinical practice. Ethical concerns make it impossible to study the impact of medication nonadherence in clinical trials, but our previous work emphasizes the importance of using preclinical approaches to address these questions. With over 30 clinically available antiseizure medicines (ASM's), it remains an important question to understand the relationship between poor adherence and seizure incidence across mechanistically distinct ASM's, including the broad-spectrum ASM, perampanel (PER). METHODS We formulated PER into chow pellets to deliver to rats in a 100% fully adherent or 50% variable nonadherent paradigm via our novel automated medication-in-food delivery system. Chronic oral dosing was initiated in male rats with chronic epilepsy while monitoring 24/7 for videoEEG evidence of seizures during a 4-week placebo baseline and 4-week treatment phase. PER concentrations were monitored in plasma at 1-week intervals and correlated with degree of seizure control. The relationship between missed doses and extended patterns of nonadherence were correlated with breakthrough seizures. RESULTS Fully adherent rats demonstrated a median reduction in seizure frequency of 50%, whereas nonadherent rats had a median increase of 54%. Plasma concentrations of PER were stable over the 4-week treatment period in both fully adherent and nonadherent groups, with levels being twice as high in fully adherent animals. There was no correlation between a single missed dose or series of missed doses and the incidence of breakthrough seizures. However, those animals in the nonadherent group that received PER for every meal during a 24-h period had a reduced likelihood of seizure incidence. CONCLUSIONS If our preclinical data is supported in the clinic, PER's favorable pharmacokinetic profile in humans, combined with a lowered risk of breakthrough seizures suggests that it may provide a certain forgiveness factor if a dose is missed within a 24-h window.
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Affiliation(s)
- Michelle Guignet
- School of Pharmacy Seattle, University of Washington, Seattle, WA, USA.
| | - Amanda Campbell
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Health Sciences Building F563, 1959 NE Pacific Street, Box 357630, Seattle, WA, 98195-7630, USA
| | - Jonathan Vuong
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Health Sciences Building F563, 1959 NE Pacific Street, Box 357630, Seattle, WA, 98195-7630, USA
| | - Dale Whittington
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA, 98159, USA
| | - H Steve White
- Center for Epilepsy Drug Discovery, Department of Pharmacy, School of Pharmacy, University of Washington, Health Sciences Building F563, 1959 NE Pacific Street, Box 357630, Seattle, WA, 98195-7630, USA
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Guignet M, Schmuck M, Harvey DJ, Nguyen D, Bruun D, Echeverri A, Gurkoff G, Lein PJ. Novel image analysis tool for rapid screening of cell morphology in preclinical animal models of disease. Heliyon 2023; 9:e13449. [PMID: 36873154 PMCID: PMC9975095 DOI: 10.1016/j.heliyon.2023.e13449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 12/18/2022] [Accepted: 01/30/2023] [Indexed: 02/10/2023] Open
Abstract
The field of cell biology has seen major advances in both cellular imaging modalities and the development of automated image analysis platforms that increase rigor, reproducibility, and throughput for large imaging data sets. However, there remains a need for tools that provide accurate morphometric analysis of single cells with complex, dynamic cytoarchitecture in a high-throughput and unbiased manner. We developed a fully automated image-analysis algorithm to rapidly detect and quantify changes in cellular morphology using microglia cells, an innate immune cell within the central nervous system, as representative of cells that exhibit dynamic and complex cytoarchitectural changes. We used two preclinical animal models that exhibit robust changes in microglia morphology: (1) a rat model of acute organophosphate intoxication, which was used to generate fluorescently labeled images for algorithm development; and (2) a rat model of traumatic brain injury, which was used to validate the algorithm using cells labeled using chromogenic detection methods. All ex vivo brain sections were immunolabeled for IBA-1 using fluorescence or diaminobenzidine (DAB) labeling, images were acquired using a high content imaging system and analyzed using a custom-built algorithm. The exploratory data set revealed eight statistically significant and quantitative morphometric parameters that distinguished between phenotypically distinct groups of microglia. Manual validation of single-cell morphology was strongly correlated with the automated analysis and was further supported by a comparison with traditional stereology methods. Existing image analysis pipelines rely on high-resolution images of individual cells, which limits sample size and is subject to selection bias. However, our fully automated method integrates quantification of morphology and fluorescent/chromogenic signals in images from multiple brain regions acquired using high-content imaging. In summary, our free, customizable image analysis tool provides a high-throughput, unbiased method for accurately detecting and quantifying morphological changes in cells with complex morphologies.
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Affiliation(s)
- Michelle Guignet
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Martin Schmuck
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Danielle J. Harvey
- Department of Public Health Sciences, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Danh Nguyen
- Division of General Internal Medicine, Department of Medicine, School of Medicine, University of California-Irvine, 100 Theory, Suite 120, Irvine, CA, 92617, USA
| | - Donald Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Angela Echeverri
- Department of Neurological Surgery, School of Medicine, University of California-Davis, 4800 Y Street, Sacramento, CA, 95817, USA
| | - Gene Gurkoff
- Department of Neurological Surgery, School of Medicine, University of California-Davis, 4800 Y Street, Sacramento, CA, 95817, USA
- Center for Neuroscience, University of California-Davis, 1544 Newton Court, Davis, CA, 95618, USA
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
- MIND Institute, School of Medicine, University of California-Davis, 2825 50th Street, Sacramento, CA, 95817, USA
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Dhir A, Bruun DA, Guignet M, Tsai Y, González E, Calsbeek J, Vu J, Saito N, Tancredi DJ, Harvey DJ, Lein PJ, Rogawski MA. Allopregnanolone and perampanel as adjuncts to midazolam for treating diisopropylfluorophosphate-induced status epilepticus in rats. Ann N Y Acad Sci 2020; 1480:183-206. [PMID: 32915470 PMCID: PMC7756871 DOI: 10.1111/nyas.14479] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/29/2020] [Accepted: 08/06/2020] [Indexed: 12/11/2022]
Abstract
Combinations of midazolam, allopregnanolone, and perampanel were assessed for antiseizure activity in a rat diisopropylfluorophosphate (DFP) status epilepticus model. Animals receiving DFP followed by atropine and pralidoxime exhibited continuous high-amplitude rhythmical electroencephalography (EEG) spike activity and behavioral seizures for more than 5 hours. Treatments were administered intramuscularly 40 min after DFP. Seizures persisted following midazolam (1.8 mg/kg). The combination of midazolam with either allopregnanolone (6 mg/kg) or perampanel (2 mg/kg) terminated EEG and behavioral status epilepticus, but the onset of the perampanel effect was slow. The combination of midazolam, allopregnanolone, and perampanel caused rapid and complete suppression of EEG and behavioral seizures. In the absence of DFP, animals treated with the three-drug combination were sedated but not anesthetized. Animals that received midazolam alone exhibited spontaneous recurrent EEG seizures, whereas those that received the three-drug combination did not, demonstrating antiepileptogenic activity. All combination treatments reduced neurodegeneration as assessed with Fluoro-Jade C staining to a greater extent than midazolam alone, and most reduced astrogliosis as assessed by GFAP immunoreactivity but had mixed effects on markers of microglial activation. We conclude that allopregnanolone, a positive modulator of the GABAA receptor, and perampanel, an AMPA receptor antagonist, are potential adjuncts to midazolam in the treatment of benzodiazepine-refractory organophosphate nerve agent-induced status epilepticus.
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Affiliation(s)
- Ashish Dhir
- Department of Neurology, School of MedicineUniversity of California, DavisSacramentoCalifornia
| | - Donald A. Bruun
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Michelle Guignet
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Yi‐Hua Tsai
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Eduardo González
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Jonas Calsbeek
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Joan Vu
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Naomi Saito
- Department of Public Health Sciences, School of MedicineUniversity of California, DavisDavisCalifornia
| | - Daniel J. Tancredi
- Department of Pediatrics, School of MedicineUniversity of California, DavisSacramentoCalifornia
| | - Danielle J. Harvey
- Department of Public Health Sciences, School of MedicineUniversity of California, DavisDavisCalifornia
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Michael A. Rogawski
- Department of Neurology, School of MedicineUniversity of California, DavisSacramentoCalifornia
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Guignet M, Campbell A, White HS. Cenobamate (XCOPRI): Can preclinical and clinical evidence provide insight into its mechanism of action? Epilepsia 2020; 61:2329-2339. [DOI: 10.1111/epi.16718] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/11/2020] [Accepted: 09/16/2020] [Indexed: 12/31/2022]
Affiliation(s)
- Michelle Guignet
- Department of Pharmacy School of Pharmacy University of Washington Seattle WA USA
| | - Amanda Campbell
- Department of Pharmacy School of Pharmacy University of Washington Seattle WA USA
| | - H. Steve White
- Department of Pharmacy School of Pharmacy University of Washington Seattle WA USA
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Guignet M, Dhakal K, Flannery BM, Hobson BA, Zolkowska D, Dhir A, Bruun DA, Li S, Wahab A, Harvey DJ, Silverman JL, Rogawski MA, Lein PJ. Persistent behavior deficits, neuroinflammation, and oxidative stress in a rat model of acute organophosphate intoxication. Neurobiol Dis 2020; 133:104431. [PMID: 30905768 PMCID: PMC6754818 DOI: 10.1016/j.nbd.2019.03.019] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 03/05/2019] [Accepted: 03/20/2019] [Indexed: 01/24/2023] Open
Abstract
Current medical countermeasures for organophosphate (OP)-induced status epilepticus (SE) are not effective in preventing long-term morbidity and there is an urgent need for improved therapies. Rat models of acute intoxication with the OP, diisopropylfluorophosphate (DFP), are increasingly being used to evaluate therapeutic candidates for efficacy in mitigating the long-term neurologic effects associated with OP-induced SE. Many of these therapeutic candidates target neuroinflammation and oxidative stress because of their implication in the pathogenesis of persistent neurologic deficits associated with OP-induced SE. Critical to these efforts is the rigorous characterization of the rat DFP model with respect to outcomes associated with acute OP intoxication in humans, which include long-term electroencephalographic, neurobehavioral, and neuropathologic effects, and their temporal relationship to neuroinflammation and oxidative stress. To address these needs, we examined a range of outcomes at later times post-exposure than have previously been reported for this model. Adult male Sprague-Dawley rats were given pyridostigmine bromide (0.1 mg/kg, im) 30 min prior to administration of DFP (4 mg/kg, sc), which was immediately followed by atropine sulfate (2 mg/kg, im) and pralidoxime (25 mg/kg, im). This exposure paradigm triggered robust electroencephalographic and behavioral seizures that rapidly progressed to SE lasting several hours in 90% of exposed animals. Animals that survived DFP-induced SE (~70%) exhibited spontaneous recurrent seizures and hyperreactive responses to tactile stimuli over the first 2 months post-exposure. Performance in the elevated plus maze, open field, and Pavlovian fear conditioning tests indicated that acute DFP intoxication reduced anxiety-like behavior and impaired learning and memory at 1 and 2 months post-exposure in the absence of effects on general locomotor behavior. Immunohistochemical analyses revealed significantly increased expression of biomarkers of reactive astrogliosis, microglial activation and oxidative stress in multiple brain regions at 1 and 2 months post-DFP, although there was significant spatiotemporal heterogeneity across these endpoints. Collectively, these data largely support the relevance of the rat model of acute DFP intoxication as a model for acute OP intoxication in the human, and support the hypothesis that neuroinflammation and/or oxidative stress represent potential therapeutic targets for mitigating the long-term neurologic sequelae of acute OP intoxication.
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Affiliation(s)
- Michelle Guignet
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
| | - Kiran Dhakal
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
| | - Brenna M. Flannery
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
| | - Brad A. Hobson
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
| | - Dorota Zolkowska
- Department of Neurology, School of Medicine, University of California-Davis, 4860 Y Street, Sacramento, CA 95817 USA, , , ;
| | - Ashish Dhir
- Department of Neurology, School of Medicine, University of California-Davis, 4860 Y Street, Sacramento, CA 95817 USA, , , ;
| | - Donald A. Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
| | - Shuyang Li
- Department of Public Health Sciences, University of California-Davis, One Shields Avenue, Davis, CA 95616 USA, ,
| | - Abdul Wahab
- Department of Neurology, School of Medicine, University of California-Davis, 4860 Y Street, Sacramento, CA 95817 USA, , , ;
| | - Danielle J. Harvey
- Department of Public Health Sciences, University of California-Davis, One Shields Avenue, Davis, CA 95616 USA, ,
| | - Jill L. Silverman
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California-Davis, 2230 Stockton Boulevard, Sacramento, CA 95817 USA,
- MIND Institute, School of Medicine, University of California-Davis, 2825 50 Street, Sacramento, CA 95817 USA
| | - Michael A. Rogawski
- Department of Neurology, School of Medicine, University of California-Davis, 4860 Y Street, Sacramento, CA 95817 USA, , , ;
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
- MIND Institute, School of Medicine, University of California-Davis, 2825 50 Street, Sacramento, CA 95817 USA
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Calsbeek J, Guignet M, Dawson M, Bruun D, Lein P. Neuroinflammatory responses in a mouse model of acute organophosphate intoxication. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.lb17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jonas Calsbeek
- Molecular BiosciencesUniversity of California, DavisDavisCA
| | | | - Mallory Dawson
- Molecular BiosciencesUniversity of California, DavisDavisCA
| | - Donald Bruun
- Molecular BiosciencesUniversity of California, DavisDavisCA
| | - Pamela Lein
- Molecular BiosciencesUniversity of California, DavisDavisCA
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Bruun DA, Guignet M, Harvey DJ, Lein PJ. Pretreatment with pyridostigmine bromide has no effect on seizure behavior or 24 hour survival in the rat model of acute diisopropylfluorophosphate intoxication. Neurotoxicology 2019; 73:81-84. [PMID: 30853371 DOI: 10.1016/j.neuro.2019.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 02/27/2019] [Accepted: 03/04/2019] [Indexed: 01/16/2023]
Abstract
Acute intoxication with organophosphate cholinesterase inhibitors (OPs) is a significant human health threat, and current medical countermeasures for OP poisoning are of limited therapeutic efficacy. The rat model of acute intoxication with diisopropylfluorophosphate (DFP) is increasingly being used to test candidate compounds for efficacy in protecting against the immediate and long-term consequences of acute OP toxicity. In this model, rats are typically pretreated with pyridostigmine bromide (PB), a reversible cholinesterase inhibitor, to enhance survival. However, PB pretreatment is not likely in most scenarios of civilian exposure to acutely neurotoxic levels of OPs. Therefore, the goal of this study was to determine whether PB pretreatment significantly increases survival in DFP-intoxicated rats. Adult male Sprague Dawley rats were injected with DFP (4 mg/kg, s.c.) or vehicle (VEH) followed 1 min later by combined i.m. injection of atropine sulfate (2 mg/kg) and 2-pralidoxime (25 mg/kg). Animals were pretreated 30 min prior to these injections with PB (0.1 mg/kg, i.m.) or an equal volume of saline. DFP triggered rapid and sustained seizure behavior irrespective of PB pretreatment, and there was no significant difference in average seizure behavior score during the first 4 h following injection between DFP animals pretreated with PB or not. PB pretreatment also had no significant effect on survival or brain AChE activity at 24 h post-DFP exposure. In summary, PB pretreatment is not necessary to ensure survival of rats acutely intoxicated with DFP, and eliminating PB pretreatment in the rat model of acute DFP intoxication would increase its relevance to acute OP intoxication in civilians.
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Affiliation(s)
- Donald A Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
| | - Michelle Guignet
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
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Guignet M, Lein PJ. Neuroinflammation in organophosphate-induced neurotoxicity. Role of Inflammation in Environmental Neurotoxicity 2019. [DOI: 10.1016/bs.ant.2018.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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