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Henion AK, Wang CP, Amuan M, Altalib HH, Towne AR, Hinds SR, Baca C, LaFrance WC, Van Cott AC, Kean J, Roghani A, Kennedy E, Panahi S, Pugh MJV. Role of Deployment History on the Association Between Epilepsy and Traumatic Brain Injury in Post-9/11 Era US Veterans. Neurology 2023; 101:e2571-e2584. [PMID: 38030395 PMCID: PMC10791059 DOI: 10.1212/wnl.0000000000207943] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/04/2023] [Indexed: 12/01/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Traumatic brain injury (TBI) is a well-established epilepsy risk factor and is common among service members. Deployment-related TBI, where combat/blast may be more common, may have different outcomes than nondeployment-related TBI. This work examined associations of all TBI exposures (not just combat), and epilepsy, while adjusting for comorbidities associated with epilepsy, among veterans by deployment status. METHODS The cohort included post-9/11 veterans with ≥2 years of care in both Veterans Health Administration and Defense Health Agency systems. We identified epilepsy using ICD-9/10-CM codes, antiseizure medication, and service-connected disability for epilepsy. We conducted a logistic regression model with interaction terms for conditions by deployment history that adjusted for demographics and military characteristics. RESULTS The cohort (n = 938,890) included post-9/11 veterans of whom 27,436 (2.92%) had epilepsy. Most veterans had a history of deployment (70.64%), referred to as "deployed." Epilepsy was more common among veterans who were never deployed ("nondeployed") (3.85% vs 2.54%). Deployed veterans were more likely to have had TBI, compared with the nondeployed veterans (33.94% vs 14.24%), but nondeployed veterans with moderate/severe TBI had higher odds of epilepsy compared with deployed veterans (adjusted odds ratio [aOR] 2.92, 95% CI 2.68-3.17 vs aOR 2.01, 95% CI 1.91-2.11). Penetrating TBI had higher odds of epilepsy among the deployed veterans (aOR 5.33, 95% CI 4.89-5.81), whereas the odds of epilepsy for mild TBI did not significantly differ by deployment status. Although most neurologic conditions were more prevalent among the nondeployed veterans, they were often associated with higher odds of epilepsy in the deployed veterans. DISCUSSION Deployment history had a significant differential impact on epilepsy predictors. As expected, penetrating TBI had a greater epilepsy impact among deployed veterans perhaps due to combat/blast. Some epilepsy predictors (moderate/severe TBI, multiple sclerosis, and Parkinson disease) had a stronger association in the nondeployed veterans suggesting a potential healthy warrior effect in which such conditions preclude deployment. Other neurologic conditions (e.g., brain tumor, Alzheimer disease/frontotemporal dementia) had a greater epilepsy impact in the deployed veterans. This may be attributable to deployment-related exposures (combat injury, occupational exposures). A better understanding of deployment effects is critical to provide targeted epilepsy prevention in veterans and military service members.
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Affiliation(s)
- Amy K Henion
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Chen-Pin Wang
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Megan Amuan
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Hamada H Altalib
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Alan R Towne
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Sidney R Hinds
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Christine Baca
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - W Curt LaFrance
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Anne C Van Cott
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Jacob Kean
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Ali Roghani
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Eamonn Kennedy
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Samin Panahi
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
| | - Mary Jo V Pugh
- From the Informatics, Decision-Enhancement and Analytic Sciences Center (IDEAS 2.0) (A.K.H., M.A., E.K., S.P., M.J.V.P.), VA Salt Lake City Health Care System, UT; Division of Epidemiology (A.K.H., A.R., E.K., S.P., M.J.V.P.), University of Utah Health Science Center, Salt Lake City; Division of General and Hospital Medicine and Department of Population Health Sciences (C.-P.W.), University of Texas Health Science Center at San Antonio; and South Texas Veterans Health Care System (C.-P.W.), San Antonio; VA Connecticut Health Care System (H.H.A.), West Haven (H.H.A.); and Department of Neurology & Psychiatry (H.H.A.), Yale School of Medicine, New Haven, CT; Department of Neurology (A.R.T.), Virginia Commonwealth University School of Medicine, Richmond; Department of Neurology/Radiology (S.R.H.), Uniformed Services University of the Health Sciences, Bethesda, MD; and SCS Consulting, LLC (S.R.H.); and NFL Players Association (S.R.H.); and Major League Soccer Players Association (S.R.H.); Epilepsy Center of Excellence (C.B.), Central Virginia Veterans Administration Hospital; and Department of Neurology (C.B.), Virginia Commonwealth University, Richmond; Departments of Psychiatry and Neurology (W.C.L.F.), Brown University; and Department of Psychiatry (W.C.L.F.), Providence VA Medical Center, RI; VA Pittsburgh Healthcare System (A.C.V.C.); and Department of Neurology (A.C.V.C.), University of Pittsburgh School of Medicine, PA; and Division of Health System Innovation and Research (J.K.), Department of Population Health Sciences, University of Utah School of Medicine, Salt Lake City
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Gudenschwager-Basso EK, Shandra O, Volanth T, Patel DC, Kelly C, Browning JL, Wei X, Harris EA, Mahmutovic D, Kaloss AM, Correa FG, Decker J, Maharathi B, Robel S, Sontheimer H, VandeVord PJ, Olsen ML, Theus MH. Atypical Neurogenesis, Astrogliosis, and Excessive Hilar Interneuron Loss Are Associated with the Development of Post-Traumatic Epilepsy. Cells 2023; 12:1248. [PMID: 37174647 PMCID: PMC10177146 DOI: 10.3390/cells12091248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 04/02/2023] [Accepted: 04/11/2023] [Indexed: 05/15/2023] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) remains a significant risk factor for post-traumatic epilepsy (PTE). The pathophysiological mechanisms underlying the injury-induced epileptogenesis are under investigation. The dentate gyrus-a structure that is highly susceptible to injury-has been implicated in the evolution of seizure development. METHODS Utilizing the murine unilateral focal control cortical impact (CCI) injury, we evaluated seizure onset using 24/7 EEG video analysis at 2-4 months post-injury. Cellular changes in the dentate gyrus and hilus of the hippocampus were quantified by unbiased stereology and Imaris image analysis to evaluate Prox1-positive cell migration, astrocyte branching, and morphology, as well as neuronal loss at four months post-injury. Isolation of region-specific astrocytes and RNA-Seq were performed to determine differential gene expression in animals that developed post-traumatic epilepsy (PTE+) vs. those animals that did not (PTE-), which may be associated with epileptogenesis. RESULTS CCI injury resulted in 37% PTE incidence, which increased with injury severity and hippocampal damage. Histological assessments uncovered a significant loss of hilar interneurons that coincided with aberrant migration of Prox1-positive granule cells and reduced astroglial branching in PTE+ compared to PTE- mice. We uniquely identified Cst3 as a PTE+-specific gene signature in astrocytes across all brain regions, which showed increased astroglial expression in the PTE+ hilus. CONCLUSIONS These findings suggest that epileptogenesis may emerge following TBI due to distinct aberrant cellular remodeling events and key molecular changes in the dentate gyrus of the hippocampus.
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Affiliation(s)
| | - Oleksii Shandra
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
- Department of Biomedical Engineering, Florida International University, Miami, FL 33199, USA
| | - Troy Volanth
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
| | - Dipan C. Patel
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
| | - Colin Kelly
- Translational Biology Medicine and Health Graduate Program, Blacksburg, VA 24061, USA
| | - Jack L. Browning
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
| | - Xiaoran Wei
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA (E.A.H.)
| | - Elizabeth A. Harris
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA (E.A.H.)
| | - Dzenis Mahmutovic
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Alexandra M. Kaloss
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA (E.A.H.)
| | | | - Jeremy Decker
- Department of Biomedical Engineering and Mechanics, Blacksburg, VA 24061, USA
| | - Biswajit Maharathi
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Stefanie Robel
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | | | - Pamela J. VandeVord
- Department of Biomedical Engineering and Mechanics, Blacksburg, VA 24061, USA
| | | | - Michelle H. Theus
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA (E.A.H.)
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
- Center for Engineered Health, Viginia Tech, Blacksburg, VA 24061, USA
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Löscher W, Stafstrom CE. Epilepsy and its neurobehavioral comorbidities: Insights gained from animal models. Epilepsia 2023; 64:54-91. [PMID: 36197310 DOI: 10.1111/epi.17433] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/04/2022] [Accepted: 10/04/2022] [Indexed: 01/21/2023]
Abstract
It is well established that epilepsy is associated with numerous neurobehavioral comorbidities, with a bidirectional relationship; people with epilepsy have an increased incidence of depression, anxiety, learning and memory difficulties, and numerous other psychosocial challenges, and the occurrence of epilepsy is higher in individuals with those comorbidities. Although the cause-and-effect relationship is uncertain, a fuller understanding of the mechanisms of comorbidities within the epilepsies could lead to improved therapeutics. Here, we review recent data on epilepsy and its neurobehavioral comorbidities, discussing mainly rodent models, which have been studied most extensively, and emphasize that clinically relevant information can be gained from preclinical models. Furthermore, we explore the numerous potential factors that may confound the interpretation of emerging data from animal models, such as the specific seizure induction method (e.g., chemical, electrical, traumatic, genetic), the role of species and strain, environmental factors (e.g., laboratory environment, handling, epigenetics), and the behavioral assays that are chosen to evaluate the various aspects of neural behavior and cognition. Overall, the interplay between epilepsy and its neurobehavioral comorbidities is undoubtedly multifactorial, involving brain structural changes, network-level differences, molecular signaling abnormalities, and other factors. Animal models are well poised to help dissect the shared pathophysiological mechanisms, neurological sequelae, and biomarkers of epilepsy and its comorbidities.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany.,Center for Systems Neuroscience, Hannover, Germany
| | - Carl E Stafstrom
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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4
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Erisken S, Nune G, Chung H, Kang JW, Koh S. Time and age dependent regulation of neuroinflammation in a rat model of mesial temporal lobe epilepsy: Correlation with human data. Front Cell Dev Biol 2022; 10:969364. [PMID: 36172274 PMCID: PMC9512631 DOI: 10.3389/fcell.2022.969364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/03/2022] [Indexed: 11/25/2022] Open
Abstract
Acute brain insults trigger diverse cellular and signaling responses and often precipitate epilepsy. The cellular, molecular and signaling events relevant to the emergence of the epileptic brain, however, remain poorly understood. These multiplex structural and functional alterations tend also to be opposing - some homeostatic and reparative while others disruptive; some associated with growth and proliferation while others, with cell death. To differentiate pathological from protective consequences, we compared seizure-induced changes in gene expression hours and days following kainic acid (KA)-induced status epilepticus (SE) in postnatal day (P) 30 and P15 rats by capitalizing on age-dependent differential physiologic responses to KA-SE; only mature rats, not immature rats, have been shown to develop spontaneous recurrent seizures after KA-SE. To correlate gene expression profiles in epileptic rats with epilepsy patients and demonstrate the clinical relevance of our findings, we performed gene analysis on four patient samples obtained from temporal lobectomy and compared to four control brains from NICHD Brain Bank. Pro-inflammatory gene expressions were at higher magnitudes and more sustained in P30. The inflammatory response was driven by the cytokines IL-1β, IL-6, and IL-18 in the acute period up to 72 h and by IL-18 in the subacute period through the 10-day time point. In addition, a panoply of other immune system genes was upregulated, including chemokines, glia markers and adhesion molecules. Genes associated with the mitogen activated protein kinase (MAPK) pathways comprised the largest functional group identified. Through the integration of multiple ontological databases, we analyzed genes belonging to 13 separate pathways linked to Classical MAPK ERK, as well as stress activated protein kinases (SAPKs) p38 and JNK. Interestingly, genes belonging to the Classical MAPK pathways were mostly transiently activated within the first 24 h, while genes in the SAPK pathways had divergent time courses of expression, showing sustained activation only in P30. Genes in P30 also had different regulatory functions than in P15: P30 animals showed marked increases in positive regulators of transcription, of signaling pathways as well as of MAPKKK cascades. Many of the same inflammation-related genes as in epileptic rats were significantly upregulated in human hippocampus, higher than in lateral temporal neocortex. They included glia-associated genes, cytokines, chemokines and adhesion molecules and MAPK pathway genes. Uniquely expressed in human hippocampus were adaptive immune system genes including immune receptors CDs and MHC II HLAs. In the brain, many immune molecules have additional roles in synaptic plasticity and the promotion of neurite outgrowth. We propose that persistent changes in inflammatory gene expression after SE leads not only to structural damage but also to aberrant synaptogenesis that may lead to epileptogenesis. Furthermore, the sustained pattern of inflammatory genes upregulated in the epileptic mature brain was distinct from that of the immature brain that show transient changes and are resistant to cell death and neuropathologic changes. Our data suggest that the epileptogenic process may be a result of failed cellular signaling mechanisms, where insults overwhelm the system beyond a homeostatic threshold.
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Affiliation(s)
- Sinem Erisken
- Department of Pediatrics, Stanley Manne Children’s Research Institute, Ann & Robert H. Lurie Children’s Hospital of Chicago, Northwestern University School of Medicine, Chicago, IL, United States
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
| | - George Nune
- Department of Pediatrics, Stanley Manne Children’s Research Institute, Ann & Robert H. Lurie Children’s Hospital of Chicago, Northwestern University School of Medicine, Chicago, IL, United States
- Department of Neurology, University of Southern California, Los Angeles, CA, United States
| | - Hyokwon Chung
- Department of Pediatrics, Stanley Manne Children’s Research Institute, Ann & Robert H. Lurie Children’s Hospital of Chicago, Northwestern University School of Medicine, Chicago, IL, United States
- Department of Pediatrics, Children’s Hospital & Medical Center, University of Nebraska, Omaha, NE, United States
| | - Joon Won Kang
- Department of Pediatrics, Children’s Hospital & Medical Center, University of Nebraska, Omaha, NE, United States
- Department of Pediatrics & Medical Science, Brain Research Institute, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Sookyong Koh
- Department of Pediatrics, Stanley Manne Children’s Research Institute, Ann & Robert H. Lurie Children’s Hospital of Chicago, Northwestern University School of Medicine, Chicago, IL, United States
- Department of Pediatrics, Children’s Hospital & Medical Center, University of Nebraska, Omaha, NE, United States
- *Correspondence: Sookyong Koh,
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5
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Gupta A, Dovek L, Proddutur A, Elgammal FS, Santhakumar V. Long-Term Effects of Moderate Concussive Brain Injury During Adolescence on Synaptic and Tonic GABA Currents in Dentate Granule Cells and Semilunar Granule Cells. Front Neurosci 2022; 16:800733. [PMID: 35360164 PMCID: PMC8964009 DOI: 10.3389/fnins.2022.800733] [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: 10/23/2021] [Accepted: 01/27/2022] [Indexed: 01/27/2023] Open
Abstract
Progressive physiological changes in the hippocampal dentate gyrus circuits following traumatic brain injury (TBI) contribute to temporal evolution of neurological sequelae. Although early posttraumatic changes in dentate synaptic and extrasynaptic GABA currents have been reported, and whether they evolve over time and remain distinct between the two projection neuron classes, granule cells and semilunar granule cells, have not been evaluated. We examined long-term changes in tonic GABA currents and spontaneous inhibitory postsynaptic currents (sIPSCs) and in dentate projection neurons 3 months after moderate concussive fluid percussion injury (FPI) in adolescent rats. Granule cell tonic GABA current amplitude remained elevated up to 1 month after FPI, but decreased to levels comparable with age-matched controls by 3 months postinjury. Granule cell sIPSC frequency, which we previously reported to be increased 1 week after FPI, remained higher than in age-matched controls at 1 month and was significantly reduced 3 months after FPI. In semilunar granule cells, tonic GABA current amplitude and sIPSC frequency were not different from controls 3 months after FPI, which contrast with decreases observed 1 week after injury. The switch in granule cell inhibitory inputs from early increase to subsequent decrease could contribute to the delayed emergence of cognitive deficits and seizure susceptibility after brain injury.
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Affiliation(s)
- Akshay Gupta
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, United States,Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Laura Dovek
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Archana Proddutur
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, United States,Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Fatima S. Elgammal
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, United States,Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States,*Correspondence: Vijayalakshmi Santhakumar,
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6
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Wang Y, Wei P, Yan F, Luo Y, Zhao G. Animal Models of Epilepsy: A Phenotype-oriented Review. Aging Dis 2022; 13:215-231. [PMID: 35111370 PMCID: PMC8782545 DOI: 10.14336/ad.2021.0723] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/23/2021] [Indexed: 12/26/2022] Open
Abstract
Epilepsy is a serious neurological disorder characterized by abnormal, recurrent, and synchronous discharges in the brain. Long-term recurrent seizure attacks can cause serious damage to brain function, which is usually observed in patients with temporal lobe epilepsy. Controlling seizure attacks is vital for the treatment and prognosis of epilepsy. Animal models, such as the kindling model, which was the most widely used model in the past, allow the understanding of the potential epileptogenic mechanisms and selection of antiepileptic drugs. In recent years, various animal models of epilepsy have been established to mimic different seizure types, without clear merits and demerits. Accordingly, this review provides a summary of the views mentioned above, aiming to provide a reference for animal model selection.
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Affiliation(s)
- Yilin Wang
- 2Institute of Cerebrovascular Diseases Research and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Penghu Wei
- 1Department of Neurosurgery, Xuanwu Hospital of Capital Medical University, Beijing, China.,4Clinical Research Center for Epilepsy Capital Medical University, Beijing, China
| | - Feng Yan
- 2Institute of Cerebrovascular Diseases Research and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yumin Luo
- 2Institute of Cerebrovascular Diseases Research and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,3Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,4Clinical Research Center for Epilepsy Capital Medical University, Beijing, China
| | - Guoguang Zhao
- 1Department of Neurosurgery, Xuanwu Hospital of Capital Medical University, Beijing, China.,3Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,4Clinical Research Center for Epilepsy Capital Medical University, Beijing, China
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Löscher W, Klein P. New approaches for developing multi-targeted drug combinations for disease modification of complex brain disorders. Does epilepsy prevention become a realistic goal? Pharmacol Ther 2021; 229:107934. [PMID: 34216705 DOI: 10.1016/j.pharmthera.2021.107934] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 12/14/2022]
Abstract
Over decades, the prevailing standard in drug discovery was the concept of designing highly selective compounds that act on individual drug targets. However, more recently, multi-target and combinatorial drug therapies have become an important treatment modality in complex diseases, including neurodegenerative diseases such as Alzheimer's and Parkinson's disease. The development of such network-based approaches is facilitated by the significant advance in our understanding of the pathophysiological processes in these and other complex brain diseases and the adoption of modern computational approaches in drug discovery and repurposing. However, although drug combination therapy has become an effective means for the symptomatic treatment of many complex diseases, the holy grail of identifying clinically effective disease-modifying treatments for neurodegenerative and other brain diseases remains elusive. Thus, despite extensive research, there remains an urgent need for novel treatments that will modify the progression of the disease or prevent its development in patients at risk. Here we discuss recent approaches with a focus on multi-targeted drug combinations for prevention or modification of epilepsy. Over the last ~10 years, several novel promising multi-targeted therapeutic approaches have been identified in animal models. We envision that synergistic combinations of repurposed drugs as presented in this review will be demonstrated to prevent epilepsy in patients at risk within the next 5-10 years.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
| | - Pavel Klein
- Mid-Atlantic Epilepsy and Sleep Center, Bethesda, MD, USA
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8
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Beamer E, Kuchukulla M, Boison D, Engel T. ATP and adenosine-Two players in the control of seizures and epilepsy development. Prog Neurobiol 2021; 204:102105. [PMID: 34144123 DOI: 10.1016/j.pneurobio.2021.102105] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/07/2021] [Accepted: 06/09/2021] [Indexed: 02/08/2023]
Abstract
Despite continuous advances in understanding the underlying pathogenesis of hyperexcitable networks and lowered seizure thresholds, the treatment of epilepsy remains a clinical challenge. Over one third of patients remain resistant to current pharmacological interventions. Moreover, even when effective in suppressing seizures, current medications are merely symptomatic without significantly altering the course of the disease. Much effort is therefore invested in identifying new treatments with novel mechanisms of action, effective in drug-refractory epilepsy patients, and with the potential to modify disease progression. Compelling evidence has demonstrated that the purines, ATP and adenosine, are key mediators of the epileptogenic process. Extracellular ATP concentrations increase dramatically under pathological conditions, where it functions as a ligand at a host of purinergic receptors. ATP, however, also forms a substrate pool for the production of adenosine, via the action of an array of extracellular ATP degrading enzymes. ATP and adenosine have assumed largely opposite roles in coupling neuronal excitability to energy homeostasis in the brain. This review integrates and critically discusses novel findings regarding how ATP and adenosine control seizures and the development of epilepsy. This includes purine receptor P1 and P2-dependent mechanisms, release and reuptake mechanisms, extracellular and intracellular purine metabolism, and emerging receptor-independent effects of purines. Finally, possible purine-based therapeutic strategies for seizure suppression and disease modification are discussed.
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Affiliation(s)
- Edward Beamer
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin D02 YN77, Ireland; Centre for Bioscience, Manchester Metropolitan University, John Dalton Building, All Saints Campus, Manchester M15 6BH, UK
| | - Manvitha Kuchukulla
- Department of Neurosurgery, Robert Wood Johnson & New Jersey Medical Schools, Rutgers University, Piscataway, NJ 08854, USA
| | - Detlev Boison
- Department of Neurosurgery, Robert Wood Johnson & New Jersey Medical Schools, Rutgers University, Piscataway, NJ 08854, USA.
| | - Tobias Engel
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin D02 YN77, Ireland; FutureNeuro, Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin D02 YN77, Ireland.
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9
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Medel-Matus JS, Shin D, Sankar R, Mazarati A. Diversity of kindling of limbic seizures after lateral fluid percussion injury in the rat. Epilepsia Open 2021; 6:413-418. [PMID: 34033249 PMCID: PMC8166798 DOI: 10.1002/epi4.12472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/31/2020] [Accepted: 01/25/2021] [Indexed: 12/19/2022] Open
Abstract
Lateral fluid percussion injury (LFPI) in rats is used to model post-traumatic epilepsy (PTE), with spontaneous seizures occurring in up to ½ of the subjects. Using the kindling paradigm, we examined whether animals without detectable seizures had an altered seizure susceptibility. Male Sprague Dawley rats were subjected to LFPI. Seven-nine months later, spontaneous seizures were monitored for two weeks. Afterward, the animals underwent kindling of basolateral amygdala. For kindling outcomes, the animals were categorized based on the 95% confidence intervals of mean number trials to kindling (ie 3 consecutive stage 4-5 seizures). Spontaneous seizures were detected in 7 out of 24 rats. There was no correlation between the severity of LFPI and either baseline afterdischarge properties, or kindling rates. Six LFPI rats kindled at a rate comparable to those in sham-LFPI (n = 10) and in naïve (n = 7) subjects. Ten LFPI rats kindled faster and 8-slower than controls. None of slow-kindling rats had spontaneous seizures during the prekindling monitoring. During the same period, six fast-kindling and three normal-kindling rats had been seizure-free. Thus, kindling reveals a diversity to seizure susceptibility after LFPI beyond an overt seizure symptomatology, ranging from the increased susceptibility to the increased resistance.
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Affiliation(s)
| | - Don Shin
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Raman Sankar
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,UCLA Children's Discovery and Innovation Institute, Los Angeles, CA, USA
| | - Andrey Mazarati
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,UCLA Children's Discovery and Innovation Institute, Los Angeles, CA, USA
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10
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Hitti FL, Piazza M, Sinha S, Kvint S, Hudgins E, Baltuch G, Diaz-Arrastia R, Davis KA, Litt B, Lucas T, Chen HI. Surgical Outcomes in Post-Traumatic Epilepsy: A Single Institutional Experience. Oper Neurosurg (Hagerstown) 2021; 18:12-18. [PMID: 30924499 DOI: 10.1093/ons/opz043] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 02/14/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Post-traumatic epilepsy (PTE) is a debilitating sequela of traumatic brain injury (TBI), occurring in up to 20% of severe cases. This entity is generally thought to be more difficult to treat with surgical intervention. OBJECTIVE To detail our experience with the surgical treatment of PTE. METHODS Patients with a history of head injury undergoing surgical treatment for epilepsy were retrospectively enrolled. Engel classification at the last follow-up was used to assess outcome of patients that underwent surgical resection of an epileptic focus. Reduction in seizure frequency was assessed for patients who underwent vagal nerve stimulator (VNS) or responsive neurostimulator (RNS) implantation. RESULTS A total of 23 patients met inclusion criteria. Nineteen (82.6%) had mesial temporal sclerosis, 3 had lesional neocortical epilepsy (13.0%), and 1 had nonlesional neocortical epilepsy (4.3%). Fourteen patients (60.9%) underwent temporal lobectomy (TL), 2 underwent resection of a cortical focus (8.7%), and 7 underwent VNS implantation (30.4%). Three patients underwent RNS implantation after VNS failed to reduce seizure frequency more than 50%. In the patients treated with resection, 11 (68.8%) were Engel I, 3 (18.8%) were Engel II, and 2 (12.5%) were Engel III at follow-up. Average seizure frequency reduction in the VNS group was 30.6% ± 25.6%. RNS patients had reduction of seizure severity but seizure frequency was only reduced 9.6% ± 13.6%. CONCLUSION Surgical outcomes of PTE patients treated with TL were similar to reported surgical outcomes of patients with nontraumatic epilepsy treated with TL. Patients who were not candidates for resection demonstrated variable response rates to VNS or RNS implantation.
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Affiliation(s)
- Frederick L Hitti
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Matthew Piazza
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Saurabh Sinha
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Svetlana Kvint
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Eric Hudgins
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Gordon Baltuch
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ramon Diaz-Arrastia
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kathryn A Davis
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Brian Litt
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Timothy Lucas
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - H Isaac Chen
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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11
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Murugan M, Boison D. Ketogenic diet, neuroprotection, and antiepileptogenesis. Epilepsy Res 2020; 167:106444. [PMID: 32854046 PMCID: PMC7655615 DOI: 10.1016/j.eplepsyres.2020.106444] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/30/2020] [Accepted: 08/13/2020] [Indexed: 12/13/2022]
Abstract
High fat, low carbohydrate ketogenic diets (KD) have been in use for the treatment of epilepsy for almost a hundred years. Remarkably, seizures that are resistant to conventional anti-seizure drugs can in many cases be controlled by the KD therapy, and it has been shown that many patients with epilepsy become seizure free even after discontinuation of the diet. These findings suggest that KD combine anti-seizure effects with disease modifying effects. In addition to the treatment of epilepsy, KDs are now widely used for the treatment of a wide range of conditions including weight reduction, diabetes, and cancer. The reason for the success of metabolic therapies is based on the synergism of at least a dozen different mechanisms through which KDs provide beneficial activities. Among the newest findings are epigenetic mechanisms (DNA methylation and histone acetylation) through which KD exerts long-lasting disease modifying effects. Here we review mechanisms through which KD can affect neuroprotection in the brain, and how a combination of those mechanisms with epigenetic alterations can attenuate and possibly reverse the development of epilepsy.
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Affiliation(s)
- Madhuvika Murugan
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854, United States
| | - Detlev Boison
- Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854, United States; Department of Neurosurgery, New Jersey Medical School, Rutgers University, Newark, NJ 07102, United States; Rutgers Neurosurgery H.O.P.E. Center, Department of Neurosurgery, Rutgers University, New Brunswick, NJ 08901, United States.
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12
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Korotkov A, Puhakka N, Gupta SD, Vuokila N, Broekaart DWM, Anink JJ, Heiskanen M, Karttunen J, van Scheppingen J, Huitinga I, Mills JD, van Vliet EA, Pitkänen A, Aronica E. Increased expression of miR142 and miR155 in glial and immune cells after traumatic brain injury may contribute to neuroinflammation via astrocyte activation. Brain Pathol 2020; 30:897-912. [PMID: 32460356 PMCID: PMC7540383 DOI: 10.1111/bpa.12865] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 02/17/2020] [Accepted: 05/15/2020] [Indexed: 12/14/2022] Open
Abstract
Traumatic brain injury (TBI) is associated with the pathological activation of immune-competent cells in the brain, such as astrocytes, microglia and infiltrating immune blood cells, resulting in chronic inflammation and gliosis. This may contribute to the secondary injury after TBI, thus understanding of these processes is crucial for the development of effective treatments of post-traumatic pathologies. MicroRNAs (miRNAs, miRs) are small noncoding RNAs, functioning as posttranscriptional regulators of gene expression. The increased expression of inflammation-associated microRNAs miR155 and miR142 has been reported after TBI in rats. However, expression of these miRNAs in the human brain post-TBI is not studied and their functions are not well understood. Moreover, circulating miR155 and miR142 are candidate biomarkers. Therefore, we characterized miR142 and miR155 expression in the perilesional cortex and plasma of rats that underwent lateral fluid-percussion injury, a model for TBI and in the human perilesional cortex post-TBI. We demonstrated higher miR155 and miR142 expression in the perilesional cortex of rats 2 weeks post-TBI. In plasma, miR155 was associated with proteins and miR142 with extracellular vesicles, however their expression did not change. In the human perilesional cortex miR155 was most prominently expressed by activated astrocytes, whereas miR142 was expressed predominantly by microglia, macrophages and lymphocytes. Pro-inflammatory medium from macrophage-like cells stimulated miR155 expression in astrocytes and overexpression of miR142 in these cells further potentiated a pro-inflammatory state of activated astrocytes. We conclude that miR155 and miR142 promote brain inflammation via astrocyte activation and may be involved in the secondary brain injury after TBI.
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Affiliation(s)
- Anatoly Korotkov
- Department of (Neuro)Pathology, Amsterdam NeuroscienceAmsterdam UMC, University of AmsterdamMeibergdreef 9Amsterdam1105 AZthe Netherlands
| | - Noora Puhakka
- Department of Neurology, A. I. Virtanen Institute for Molecular SciencesUniversity of Eastern FinlandKuopioFI‐70211Finland
| | - Shalini Das Gupta
- Department of Neurology, A. I. Virtanen Institute for Molecular SciencesUniversity of Eastern FinlandKuopioFI‐70211Finland
| | - Niina Vuokila
- Department of Neurology, A. I. Virtanen Institute for Molecular SciencesUniversity of Eastern FinlandKuopioFI‐70211Finland
| | - Diede W. M. Broekaart
- Department of (Neuro)Pathology, Amsterdam NeuroscienceAmsterdam UMC, University of AmsterdamMeibergdreef 9Amsterdam1105 AZthe Netherlands
| | - Jasper J. Anink
- Department of (Neuro)Pathology, Amsterdam NeuroscienceAmsterdam UMC, University of AmsterdamMeibergdreef 9Amsterdam1105 AZthe Netherlands
| | - Mette Heiskanen
- Department of Neurology, A. I. Virtanen Institute for Molecular SciencesUniversity of Eastern FinlandKuopioFI‐70211Finland
| | - Jenni Karttunen
- Department of Neurology, A. I. Virtanen Institute for Molecular SciencesUniversity of Eastern FinlandKuopioFI‐70211Finland
| | - Jackelien van Scheppingen
- Department of (Neuro)Pathology, Amsterdam NeuroscienceAmsterdam UMC, University of AmsterdamMeibergdreef 9Amsterdam1105 AZthe Netherlands
- Department of NeuroimmunologyNetherlands Institute for NeuroscienceMeibergdreef 47Amsterdam1105 BAthe Netherlands
| | - Inge Huitinga
- Department of NeuroimmunologyNetherlands Institute for NeuroscienceMeibergdreef 47Amsterdam1105 BAthe Netherlands
| | - James D. Mills
- Department of (Neuro)Pathology, Amsterdam NeuroscienceAmsterdam UMC, University of AmsterdamMeibergdreef 9Amsterdam1105 AZthe Netherlands
| | - Erwin A. van Vliet
- Department of (Neuro)Pathology, Amsterdam NeuroscienceAmsterdam UMC, University of AmsterdamMeibergdreef 9Amsterdam1105 AZthe Netherlands
- Swammerdam Institute for Life Sciences, Center for NeuroscienceUniversity of AmsterdamScience Park 904Amsterdam1090 GEthe Netherlands
| | - Asla Pitkänen
- Department of Neurology, A. I. Virtanen Institute for Molecular SciencesUniversity of Eastern FinlandKuopioFI‐70211Finland
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam NeuroscienceAmsterdam UMC, University of AmsterdamMeibergdreef 9Amsterdam1105 AZthe Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN)Heemstedethe Netherlands
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13
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Cho S, Park E, Telliyan T, Baker A, Reid AY. Zebrafish model of posttraumatic epilepsy. Epilepsia 2020; 61:1774-1785. [DOI: 10.1111/epi.16589] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 06/02/2020] [Accepted: 06/02/2020] [Indexed: 01/03/2023]
Affiliation(s)
- Sung‐Joon Cho
- Division of Fundamental Neurobiology Krembil Research Institute University Health Network Toronto Ontario Canada
- Collaborative Program in Neuroscience University of Toronto Toronto Ontario Canada
- Keenan Research Centre Li Ka Shing Knowledge Institute St. Michael's Hospital Toronto Ontario Canada
| | - Eugene Park
- Keenan Research Centre Li Ka Shing Knowledge Institute St. Michael's Hospital Toronto Ontario Canada
| | - Tamar Telliyan
- Keenan Research Centre Li Ka Shing Knowledge Institute St. Michael's Hospital Toronto Ontario Canada
| | - Andrew Baker
- Keenan Research Centre Li Ka Shing Knowledge Institute St. Michael's Hospital Toronto Ontario Canada
- Department of Anesthesia and Surgery University of Toronto Toronto Ontario Canada
| | - Aylin Y. Reid
- Division of Fundamental Neurobiology Krembil Research Institute University Health Network Toronto Ontario Canada
- Department of Medicine University of Toronto Toronto Ontario Canada
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14
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Panagopoulos D, Markogiannakis G, Themistocleous M. Post-Traumatic Status Epilepticus Masquerading as Acute Ischemic Stroke: A Case Report and Literature Review. AMERICAN JOURNAL OF CASE REPORTS 2020; 21:e922679. [PMID: 32362653 PMCID: PMC7213816 DOI: 10.12659/ajcr.922679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Patient: Male, 7-year-old Final Diagnosis: Status epilepticus Symptoms: Local sezure Medication: — Clinical Procedure: Computed tomography • magnetic resonance imaging Specialty: Neurosurgery
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Affiliation(s)
| | | | - Marios Themistocleous
- Department of Neurosurgery, Pediatric Hospital of Athens, Agia Sophia, Athens, Greece
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15
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Dehydroepiandrosterone alleviates oxidative stress and apoptosis in iron-induced epilepsy via activation of Nrf2/ARE signal pathway. Brain Res Bull 2019; 153:181-190. [DOI: 10.1016/j.brainresbull.2019.08.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 08/16/2019] [Accepted: 08/26/2019] [Indexed: 12/26/2022]
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16
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Lu XCM, Browning J, Liao Z, Cao Y, Yang W, Shear DA. Post-Traumatic Epilepsy and Seizure Susceptibility in Rat Models of Penetrating and Closed-Head Brain Injury. J Neurotrauma 2019; 37:236-247. [PMID: 31530242 DOI: 10.1089/neu.2019.6573] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Traumatic brain injury (TBI) carries a risk of developing post-traumatic epilepsy (PTE). Currently, animal models that replicate clinical PTE (delayed spontaneous and recurrent seizures) are limited, which hinders pre-clinical research. In this study, we used two rat models of penetrating ballistic-like brain injury (PBBI) and closed-head injury (CHI) to induce spontaneous seizures and also measure changes in seizure susceptibility. In the PBBI model, two trajectories (frontal and lateral) and two injury severities for each trajectory, were evaluated. In the CHI model, a single projectile impact to the dorsal/lateral region of the head was tested. Continuous video-electroencephalographic (EEG) recordings were collected for 10 days at 1 or 6 month(s) post-injury. After EEG recording, all rats were given a sub-convulsant dose of pentylenetetrazole (PTZ) to challenge the seizure susceptibility. The video-EEG recording did not detect PTE following the PBBI. Only one CHI rat demonstrated persistent and recurrent non-convulsive seizures detected at 6 months post-injury. However, after PTZ challenge, 50-100% of the animals across different TBI groups experienced seizures. Seizure susceptibility increased over time from 1 to 6 months post-injury across the majority of TBI groups. Injury severity effects were not apparent within the PBBI model, but were evident between PBBI and CHI models. These results demonstrated the difficulties in detecting delayed spontaneous post-traumatic seizures even in a high-risk model of penetrating brain injury. The PTZ-induced increase in seizure susceptibility indicated the existence of vulnerable risk of epileptogenesis following TBI, which may be considered as an alternative research tool for pre-clinical studies of PTE.
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Affiliation(s)
- Xi-Chun M Lu
- Branch of Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Jenny Browning
- Branch of Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Zhilin Liao
- Branch of Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Ying Cao
- Branch of Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Weihong Yang
- Branch of Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Deborah A Shear
- Branch of Brain Trauma Neuroprotection, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, Maryland
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17
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Cela E, Sjöström PJ. Novel Optogenetic Approaches in Epilepsy Research. Front Neurosci 2019; 13:947. [PMID: 31551699 PMCID: PMC6743373 DOI: 10.3389/fnins.2019.00947] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/22/2019] [Indexed: 11/13/2022] Open
Abstract
Epilepsy is a major neurological disorder characterized by repeated seizures afflicting 1% of the global population. The emergence of seizures is associated with several comorbidities and severely decreases the quality of life of patients. Unfortunately, around 30% of patients do not respond to first-line treatment using anti-seizure drugs (ASDs). Furthermore, it is still unclear how seizures arise in the healthy brain. Therefore, it is critical to have well developed models where a causal understanding of epilepsy can be investigated. While the development of seizures has been studied in several animal models, using chemical or electrical induction, deciphering the results of such studies has been difficult due to the uncertainty of the cell population being targeted as well as potential confounds such as brain damage from the procedure itself. Here we describe novel approaches using combinations of optical and genetic methods for studying epileptogenesis. These approaches can circumvent some shortcomings associated with the classical animal models and may thus increase the likelihood of developing new treatment options.
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Affiliation(s)
- Elvis Cela
- Brain Repair and Integrative Neuroscience Program, Centre for Research in Neuroscience, Department of Medicine, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Per Jesper Sjöström
- Brain Repair and Integrative Neuroscience Program, Centre for Research in Neuroscience, Department of Medicine, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
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18
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Riese F, Meyerhoff N, Nessler J, Tipold A. Misery of insufficient treatment guidelines in post‐traumatic epilepsy. VETERINARY RECORD CASE REPORTS 2019. [DOI: 10.1136/vetreccr-2018-000716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Franziska Riese
- Department of Small Animal Medicine and SurgeryKlinik fuer Kleine HaustiereStiftung Tierarztliche Hochschule HannoverHannoverGermany
| | - Nina Meyerhoff
- Department of Small Animal Medicine and SurgeryKlinik fuer Kleine HaustiereStiftung Tierarztliche Hochschule HannoverHannoverGermany
| | - Jasmin Nessler
- Department of Small Animal Medicine and SurgeryKlinik fuer Kleine HaustiereStiftung Tierarztliche Hochschule HannoverHannoverGermany
| | - Andrea Tipold
- Department of Small Animal Medicine and SurgeryKlinik fuer Kleine HaustiereStiftung Tierarztliche Hochschule HannoverHannoverGermany
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19
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Leung WL, Casillas-Espinosa P, Sharma P, Perucca P, Powell K, O'Brien TJ, Semple BD. An animal model of genetic predisposition to develop acquired epileptogenesis: The FAST and SLOW rats. Epilepsia 2019; 60:2023-2036. [PMID: 31468516 DOI: 10.1111/epi.16329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 08/06/2019] [Accepted: 08/06/2019] [Indexed: 12/12/2022]
Abstract
Epidemiological data and gene association studies suggest a genetic predisposition to developing epilepsy after an acquired brain insult, such as traumatic brain injury. An improved understanding of genetic determinants of vulnerability is imperative for early disease diagnosis and prognosis prediction, with flow-on benefits for the development of targeted antiepileptogenic treatments as well as optimal clinical trial design. In the laboratory, one approach to investigate why some individuals are more vulnerable to acquired epilepsy than others is to examine unique rodent models exhibiting either vulnerability or resistance to epileptogenesis. This review focuses on the most well-characterized of these models, the FAST (seizure-prone) and SLOW (seizure-resistant) rat strains, which were derived by selective breeding for differential amygdala electrical kindling rates. We describe how these strains differ in their seizure profiles, neuroanatomy, and neurobehavioral phenotypes, both at baseline and after a brain insult, with this knowledge proving fruitful to identify common pathological abnormalities associated with seizure susceptibility and psychiatric comorbidities. It is important to note that accruing data on strain differences in multiple biological processes provides insight into why some individuals may be more vulnerable to epileptogenesis, although future studies are evidently needed to identify the precise molecular and genetic risk factors. Together, the FAST and SLOW rat strains, and other similar experimental models, are invaluable neurobiological tools to investigate the effect of genetic background on acquired epilepsy risk, as well as the poorly understood relationship between epilepsy development and associated comorbidities.
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Affiliation(s)
- Wai Lam Leung
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia
| | - Pablo Casillas-Espinosa
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia
| | - Pragati Sharma
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia.,Department of Neurology, Alfred Health, Melbourne, Vic., Australia
| | - Piero Perucca
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia.,Department of Neurology, Alfred Health, Melbourne, Vic., Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, Vic., Australia
| | - Kim Powell
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia
| | - Terence J O'Brien
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia.,Department of Neurology, Alfred Health, Melbourne, Vic., Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, Vic., Australia
| | - Bridgette D Semple
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Vic., Australia
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20
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Noè F, Cattalini A, Vila Verde D, Alessi C, Colciaghi F, Figini M, Zucca I, de Curtis M. Epileptiform activity contralateral to unilateral hippocampal sclerosis does not cause the expression of brain damage markers. Epilepsia 2019; 60:1184-1199. [PMID: 31111475 DOI: 10.1111/epi.15611] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/24/2019] [Accepted: 04/24/2019] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Patients with epilepsy often ask if recurrent seizures harm their brain and aggravate their epileptic condition. This crucial question has not been specifically addressed by dedicated experiments. We analyze here if intense bilateral seizure activity induced by local injection of kainic acid (KA) in the right hippocampus produces brain damage in the left hippocampus. METHODS Adult guinea pigs were bilaterally implanted with hippocampal electrodes for continuous video-electroencephalography (EEG) monitoring. Unilateral injection of 1 μg KA in the dorsal CA1 area induced nonconvulsive status epilepticus (ncSE) characterized by bilateral hippocampal seizure discharges. This treatment resulted in selective unilateral sclerosis of the KA-injected hippocampus. Three days after KA injection, the animals were killed, and the brains were submitted to ex vivo magnetic resonance imaging (MRI) and were processed for immunohistochemical analysis. RESULTS During ncSE, epileptiform activity was recorded for 27.6 ± 19.1 hours in both the KA-injected and contralateral hippocampi. Enhanced T1-weighted MR signal due to gadolinium deposition, mean diffusivity reduction, neuronal loss, gliosis, and blood-brain barrier permeability changes was observed exclusively in the KA-injected hippocampus. Despite the presence of a clear unilateral hippocampal sclerosis at the site of KA injection, no structural alterations were detected by MR and immunostaining analysis performed in the hippocampus contralateral to KA injection 3 days and 2 months after ncSE induction. Fluoro-Jade and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining at the same time points confirmed the absence of degenerating cells in the hippocampi contralateral to KA injection. SIGNIFICANCE We demonstrate that intense epileptiform activity during ncSE does not cause obvious brain damage in the hippocampus contralateral to unilateral hippocampal KA injection. These findings argue against the hypothesis that epileptiform activity per se contributes to focal brain injury in previously undamaged cortical regions.
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Affiliation(s)
- Francesco Noè
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | | | - Diogo Vila Verde
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Camilla Alessi
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Francesca Colciaghi
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Matteo Figini
- Scientific Direction, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Ileana Zucca
- Scientific Direction, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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21
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CRF Mediates Stress-Induced Pathophysiological High-Frequency Oscillations in Traumatic Brain Injury. eNeuro 2019; 6:ENEURO.0334-18.2019. [PMID: 31040158 PMCID: PMC6514440 DOI: 10.1523/eneuro.0334-18.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 04/01/2019] [Accepted: 04/20/2019] [Indexed: 01/19/2023] Open
Abstract
It is not known why there is increased risk to have seizures with increased anxiety and stress after traumatic brain injury (TBI). Stressors cause the release of corticotropin-releasing factor (CRF) both from the hypothalamic pituitary adrenal (HPA) axis and from CNS neurons located in the central amygdala and GABAergic interneurons. We have previously shown that CRF signaling is plastic, becoming excitatory instead of inhibitory after the kindling model of epilepsy. Here, using Sprague Dawley rats we have found that CRF signaling increased excitability after TBI. Following TBI, CRF type 1 receptor (CRFR1)-mediated activity caused abnormally large electrical responses in the amygdala, including fast ripples, which are considered to be epileptogenic. After TBI, we also found the ripple (120-250 Hz) and fast ripple activity (>250 Hz) was cross-frequency coupled with θ (3-8 Hz) oscillations. CRFR1 antagonists reduced the incidence of phase coupling between ripples and fast ripples. Our observations indicate that pathophysiological signaling of the CRFR1 increases the incidence of epileptiform activity after TBI. The use for CRFR1 antagonist may be useful to reduce the severity and frequency of TBI associated epileptic seizures.
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22
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Witkowski ED, Gao Y, Gavsyuk AF, Maor I, DeWalt GJ, Eldred WD, Mizrahi A, Davison IG. Rapid Changes in Synaptic Strength After Mild Traumatic Brain Injury. Front Cell Neurosci 2019; 13:166. [PMID: 31105533 PMCID: PMC6498971 DOI: 10.3389/fncel.2019.00166] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 04/08/2019] [Indexed: 12/12/2022] Open
Abstract
Traumatic brain injury (TBI) affects millions of Americans annually, but effective treatments remain inadequate due to our poor understanding of how injury impacts neural function. Data are particularly limited for mild, closed-skull TBI, which forms the majority of human cases, and for acute injury phases, when trauma effects and compensatory responses appear highly dynamic. Here we use a mouse model of mild TBI to characterize injury-induced synaptic dysfunction, and examine its progression over the hours to days after trauma. Mild injury consistently caused both locomotor deficits and localized neuroinflammation in piriform and entorhinal cortices, along with reduced olfactory discrimination ability. Using whole-cell recordings to characterize synaptic input onto piriform pyramidal neurons, we found moderate effects on excitatory or inhibitory synaptic function at 48 h after TBI and robust increase in excitatory inputs in slices prepared 1 h after injury. Excitatory increases predominated over inhibitory effects, suggesting that loss of excitatory-inhibitory balance is a common feature of both mild and severe TBI. Our data indicate that mild injury drives rapidly evolving alterations in neural function in the hours following injury, highlighting the need to better characterize the interplay between the primary trauma responses and compensatory effects during this early time period.
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Affiliation(s)
| | - Yuan Gao
- Department of Biology, Boston University, Boston, MA, United States
| | | | - Ido Maor
- Department of Neurobiology, Edmond & Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Gloria J. DeWalt
- Department of Biology, Boston University, Boston, MA, United States
| | | | - Adi Mizrahi
- Department of Neurobiology, Edmond & Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ian G. Davison
- Department of Biology, Boston University, Boston, MA, United States
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23
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Löscher W. The holy grail of epilepsy prevention: Preclinical approaches to antiepileptogenic treatments. Neuropharmacology 2019; 167:107605. [PMID: 30980836 DOI: 10.1016/j.neuropharm.2019.04.011] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/03/2019] [Accepted: 04/09/2019] [Indexed: 02/06/2023]
Abstract
A variety of acute brain insults can induce epileptogenesis, a complex process that results in acquired epilepsy. Despite advances in understanding mechanisms of epileptogenesis, there is currently no approved treatment that prevents the development or progression of epilepsy in patients at risk. The current concept of epileptogenesis assumes a window of opportunity following acute brain insults that allows intervention with preventive treatment. Recent results suggest that injury-induced epileptogenesis can be a much more rapid process than previously thought, suggesting that the 'therapeutic window' may only be open for a brief period, as in stroke therapy. However, experimental data also suggest a second, possibly delayed process ("secondary epileptogenesis") that influences the progression and refractoriness of the epileptic state over time, allowing interfering with this process even after onset of epilepsy. In this review, both methodological issues in preclinical drug development and novel targets for antiepileptogenesis will be discussed. Several promising drugs that either prevent epilepsy (antiepileptogenesis) or slow epilepsy progression and alleviate cognitive or behavioral comorbidities of epilepsy (disease modification) have been described in recent years, using diverse animal models of acquired epilepsy. Promising agents include TrkB inhibitors, losartan, statins, isoflurane, anti-inflammatory and anti-oxidative drugs, the SV2A modulator levetiracetam, and epigenetic interventions. Research on translational target validity and on prognostic biomarkers that can be used to stratify patients (or experimental animals) at high risk of developing epilepsy will hopefully soon lead to proof-of-concept clinical trials with the most promising drugs, which will be essential to make prevention of epilepsy a reality. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
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24
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Cela E, McFarlan AR, Chung AJ, Wang T, Chierzi S, Murai KK, Sjöström PJ. An Optogenetic Kindling Model of Neocortical Epilepsy. Sci Rep 2019; 9:5236. [PMID: 30918286 PMCID: PMC6437216 DOI: 10.1038/s41598-019-41533-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/11/2019] [Indexed: 01/26/2023] Open
Abstract
Epileptogenesis is the gradual process by which the healthy brain develops epilepsy. However, the neuronal circuit changes that underlie epileptogenesis are not well understood. Unfortunately, current chemically or electrically induced epilepsy models suffer from lack of cell specificity, so it is seldom known which cells were activated during epileptogenesis. We therefore sought to develop an optogenetic variant of the classical kindling model of epilepsy in which activatable cells are both genetically defined and fluorescently tagged. We briefly optogenetically activated pyramidal cells (PCs) in awake behaving mice every two days and conducted a series of experiments to validate the effectiveness of the model. Although initially inert, brief optogenetic stimuli eventually elicited seizures that increased in number and severity with additional stimulation sessions. Seizures were associated with long-lasting plasticity, but not with tissue damage or astrocyte reactivity. Once optokindled, mice retained an elevated seizure susceptibility for several weeks in the absence of additional stimulation, indicating a form of long-term sensitization. We conclude that optokindling shares many features with classical kindling, with the added benefit that the role of specific neuronal populations in epileptogenesis can be studied. Links between long-term plasticity and epilepsy can thus be elucidated.
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Affiliation(s)
- Elvis Cela
- Brain Repair and Integrative Neuroscience Program, Centre for Research in Neuroscience, Departments of Medicine, and Neurology & Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, H3G 1A4, Canada.,Integrated Program in Neuroscience, McGill University, 3801 University Street, Montreal, Quebec, H3A 2B4, Canada
| | - Amanda R McFarlan
- Brain Repair and Integrative Neuroscience Program, Centre for Research in Neuroscience, Departments of Medicine, and Neurology & Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, H3G 1A4, Canada.,Integrated Program in Neuroscience, McGill University, 3801 University Street, Montreal, Quebec, H3A 2B4, Canada
| | - Andrew J Chung
- Brain Repair and Integrative Neuroscience Program, Centre for Research in Neuroscience, Departments of Medicine, and Neurology & Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, H3G 1A4, Canada
| | - Taiji Wang
- Brain Repair and Integrative Neuroscience Program, Centre for Research in Neuroscience, Departments of Medicine, and Neurology & Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, H3G 1A4, Canada
| | - Sabrina Chierzi
- Brain Repair and Integrative Neuroscience Program, Centre for Research in Neuroscience, Departments of Medicine, and Neurology & Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, H3G 1A4, Canada
| | - Keith K Murai
- Brain Repair and Integrative Neuroscience Program, Centre for Research in Neuroscience, Departments of Medicine, and Neurology & Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, H3G 1A4, Canada
| | - P Jesper Sjöström
- Brain Repair and Integrative Neuroscience Program, Centre for Research in Neuroscience, Departments of Medicine, and Neurology & Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, H3G 1A4, Canada.
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25
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Huttunen JK, Airaksinen AM, Barba C, Colicchio G, Niskanen JP, Shatillo A, Sierra Lopez A, Ndode-Ekane XE, Pitkänen A, Gröhn OH. Detection of Hyperexcitability by Functional Magnetic Resonance Imaging after Experimental Traumatic Brain Injury. J Neurotrauma 2018; 35:2708-2717. [DOI: 10.1089/neu.2017.5308] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Joanna K. Huttunen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Antti M. Airaksinen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Carmen Barba
- Neuroscience Department, Children's Hospital Anna Meyer, Florence, Italy
| | | | - Juha-Pekka Niskanen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Artem Shatillo
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Alejandra Sierra Lopez
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | | | - Asla Pitkänen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Olli H. Gröhn
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
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26
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Bialer M, Johannessen SI, Koepp MJ, Levy RH, Perucca E, Tomson T, White HS. Progress report on new antiepileptic drugs: A summary of the Fourteenth Eilat Conference on New Antiepileptic Drugs and Devices (EILAT XIV). I. Drugs in preclinical and early clinical development. Epilepsia 2018; 59:1811-1841. [DOI: 10.1111/epi.14557] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/08/2018] [Accepted: 08/08/2018] [Indexed: 01/06/2023]
Affiliation(s)
- Meir Bialer
- Faculty of Medicine; School of Pharmacy and David R. Bloom Center for Pharmacy; Institute for Drug Research; Hebrew University of Jerusalem; Jerusalem Israel
| | - Svein I. Johannessen
- National Center for Epilepsy; Sandvika Norway
- Department of Pharmacology; Oslo University Hospital; Oslo Norway
| | - Matthias J. Koepp
- Department of Clinical and Experimental Epilepsy; UCL Institute of Neurology; London UK
| | - René H. Levy
- Departments of Pharmaceutics and Neurological Surgery; University of Washington; Seattle Washington
| | - Emilio Perucca
- Department of Internal Medicine and Therapeutics; University of Pavia; Pavia Italy
- IRCCS Mondino Foundation; Pavia Italy
| | - Torbjörn Tomson
- Department of Clinical Neuroscience; Karolinska Institute; Stockholm Sweden
| | - H. Steve White
- Department of Pharmacy; School of Pharmacy; University of Washington; Seattle Washington
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27
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Gorlewicz A, Kaczmarek L. Pathophysiology of Trans-Synaptic Adhesion Molecules: Implications for Epilepsy. Front Cell Dev Biol 2018; 6:119. [PMID: 30298130 PMCID: PMC6160742 DOI: 10.3389/fcell.2018.00119] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022] Open
Abstract
Chemical synapses are specialized interfaces between neurons in the brain that transmit and modulate information, thereby integrating cells into multiplicity of interacting neural circuits. Cell adhesion molecules (CAMs) might form trans-synaptic complexes that are crucial for the appropriate identification of synaptic partners and further for the establishment, properties, and dynamics of synapses. When affected, trans-synaptic adhesion mechanisms play a role in synaptopathies in a variety of neuropsychiatric disorders including epilepsy. This review recapitulates current understanding of trans-synaptic interactions in pathophysiology of interneuronal connections. In particular, we discuss here the possible implications of trans-synaptic adhesion dysfunction for epilepsy.
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Affiliation(s)
- Adam Gorlewicz
- Laboratory of Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
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28
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Komol’tsev IG, Volkova AA, Levshina IP, Novikova MR, Manolova AO, Stepanichev MY, Gulyaeva NV. The Number of IgG-Positive Neurons in the Rat Hippocampus Increases after Dosed Traumatic Brain Injury. NEUROCHEM J+ 2018. [DOI: 10.1134/s1819712418030054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Brady RD, Casillas-Espinosa PM, Agoston DV, Bertram EH, Kamnaksh A, Semple BD, Shultz SR. Modelling traumatic brain injury and posttraumatic epilepsy in rodents. Neurobiol Dis 2018; 123:8-19. [PMID: 30121231 DOI: 10.1016/j.nbd.2018.08.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 07/25/2018] [Accepted: 08/13/2018] [Indexed: 12/14/2022] Open
Abstract
Posttraumatic epilepsy (PTE) is one of the most debilitating and understudied consequences of traumatic brain injury (TBI). It is challenging to study the effects, underlying pathophysiology, biomarkers, and treatment of TBI and PTE purely in human patients for a number of reasons. Rodent models can complement human PTE studies as they allow for the rigorous investigation into the causal relationship between TBI and PTE, the pathophysiological mechanisms of PTE, the validation and implementation of PTE biomarkers, and the assessment of PTE treatments, in a tightly controlled, time- and cost-efficient manner in experimental subjects known to be experiencing epileptogenic processes. This article will review several common rodent models of TBI and/or PTE, including their use in previous studies and discuss their relative strengths, limitations, and avenues for future research to advance our understanding and treatment of PTE.
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Affiliation(s)
- Rhys D Brady
- Departments of Neuroscience and Medicine, Central Clinical School, Monash University, VIC 3004, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, VIC 3052, Australia.
| | - Pablo M Casillas-Espinosa
- Departments of Neuroscience and Medicine, Central Clinical School, Monash University, VIC 3004, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, VIC 3052, Australia.
| | - Denes V Agoston
- Anatomy, Physiology & Genetics, Uniformed Services University, Bethesda, MD 20814, USA
| | - Edward H Bertram
- Department of Neurology, University of Virginia, P.O. Box 800394, Charlottesville, VA 22908-0394, USA
| | - Alaa Kamnaksh
- Anatomy, Physiology & Genetics, Uniformed Services University, Bethesda, MD 20814, USA
| | - Bridgette D Semple
- Departments of Neuroscience and Medicine, Central Clinical School, Monash University, VIC 3004, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, VIC 3052, Australia
| | - Sandy R Shultz
- Departments of Neuroscience and Medicine, Central Clinical School, Monash University, VIC 3004, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, VIC 3052, Australia
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Protein biomarkers of epileptogenicity after traumatic brain injury. Neurobiol Dis 2018; 123:59-68. [PMID: 30030023 DOI: 10.1016/j.nbd.2018.07.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 07/10/2018] [Accepted: 07/16/2018] [Indexed: 12/15/2022] Open
Abstract
Traumatic brain injury (TBI) is a major risk factor for acquired epilepsy. Post-traumatic epilepsy (PTE) develops over time in up to 50% of patients with severe TBI. PTE is mostly unresponsive to traditional anti-seizure treatments suggesting distinct, injury-induced pathomechanisms in the development of this condition. Moderate and severe TBIs cause significant tissue damage, bleeding, neuron and glia death, as well as axonal, vascular, and metabolic abnormalities. These changes trigger a complex biological response aimed at curtailing the physical damage and restoring homeostasis and functionality. Although a positive correlation exists between the type and severity of TBI and PTE, there is only an incomplete understanding of the time-dependent sequelae of TBI pathobiologies and their role in epileptogenesis. Determining the temporal profile of protein biomarkers in the blood (serum or plasma) and cerebrospinal fluid (CSF) can help to identify pathobiologies underlying the development of PTE, high-risk individuals, and disease modifying therapies. Here we review the pathobiological sequelae of TBI in the context of blood- and CSF-based protein biomarkers, their potential role in epileptogenesis, and discuss future directions aimed at improving the diagnosis and treatment of PTE.
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Hsieh TH, Lee HHC, Hameed MQ, Pascual-Leone A, Hensch TK, Rotenberg A. Trajectory of Parvalbumin Cell Impairment and Loss of Cortical Inhibition in Traumatic Brain Injury. Cereb Cortex 2018; 27:5509-5524. [PMID: 27909008 DOI: 10.1093/cercor/bhw318] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 09/21/2016] [Indexed: 11/13/2022] Open
Abstract
Many neuropsychiatric symptoms that follow traumatic brain injury (TBI), including mood disorders, sleep disturbance, chronic pain, and posttraumatic epilepsy (PTE) are attributable to compromised cortical inhibition. However, the temporal trajectory of cortical inhibition loss and its underlying mechanisms are not known. Using paired-pulse transcranial magnetic stimulation (ppTMS) and immunohistochemistry, we tracked functional and cellular changes of cortical inhibitory network elements after fluid-percussion injury (FPI) in rats. ppTMS revealed a progressive loss of cortical inhibition as early as 2 weeks after FPI. This profile paralleled the increasing levels of cortical oxidative stress, which was accompanied by a gradual loss of parvalbumin (PV) immunoreactivity in perilesional cortex. Preceding the PV loss, we identified a degradation of the perineuronal net (PNN)-a specialized extracellular structure enwrapping cortical PV-positive (PV+) inhibitory interneurons which binds the PV+ cell maintenance factor, Otx2. The trajectory of these impairments underlies the reduced inhibitory tone, which can contribute to posttraumatic neurological conditions, such as PTE. Taken together, our results highlight the use of ppTMS as a biomarker to track the course of cortical inhibitory dysfunction post-TBI. Moreover, the neuroprotective role of PNNs on PV+ cell function suggests antioxidant treatment or Otx2 enhancement as a promising prophylaxis for post-TBI symptoms.
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Affiliation(s)
- Tsung-Hsun Hsieh
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan.,Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 33305, Taiwan
| | - Henry Hing Cheong Lee
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Mustafa Qadir Hameed
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Takao K Hensch
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, MA 02138, USA
| | - Alexander Rotenberg
- Neuromodulation Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.,Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
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Reddy DS, Yoshimura RF, Ramanathan G, Carver C, Johnstone TB, Hogenkamp DJ, Gee KW. Role of β 2/3-specific GABA-A receptor isoforms in the development of hippocampus kindling epileptogenesis. Epilepsy Behav 2018; 82:57-63. [PMID: 29587186 DOI: 10.1016/j.yebeh.2018.02.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/16/2018] [Accepted: 02/20/2018] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Subunit-specific positive allosteric modulators (PAMs) of gamma-aminobutyric acid-A (GABA-A) receptors are commonly used to uncover the role of GABA-A receptor isoforms in brain function. Recently, we have designed novel PAMs selective for β2/3-subunit containing GABA-A receptors (β2/3-selective PAMs) that are nonbenzodiazepine site-mediated and do not show an α-subunit isoform selectivity, yet exhibit anxiolytic efficacy with reduced potential for sedation, cognitive impairment, and tolerance. In this study, we used three novel β2/3-selective PAMs (2-261, 2-262, and 10029) with differential β2/3-subunit potency to identify the role of β2/3-selective receptor isoforms in limbic epileptogenesis. METHODS Experimental epileptogenesis was induced in mice by daily hippocampus stimulations until each mouse showed generalized (stage 5) seizures. Patch-clamp electrophysiology was used to record GABA-gated currents. Brain levels of β2/3-selective PAMs were determined for mechanistic correlations. RESULTS Treatment with the β2/3-selective PAMs 2-261 (30mg/kg), 2-262 (10mg/kg), and 10029 (30mg/kg), 30min prior to stimulations, significantly suppressed the rate of development of kindled seizure activity without affecting the afterdischarge (AD) signal, indicating their disease-modifying activity. The β2/3-selective agents suppressed chemical epileptogenesis in the pentylenetetrazol model. Test doses of these agents were devoid of acute antiseizure activity in the kindling model. CONCLUSION These findings demonstrate that β2/3-selective PAMs can moderately retard experimental epileptogenesis, indicating the protective role of β2/3-subunit GABA-A receptor isoforms in the development of epilepsy.
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Affiliation(s)
- Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, United States.
| | - Ryan F Yoshimura
- Department of Pharmacology, School of Medicine, University of California, Irvine, California, United States
| | - Gunasekaran Ramanathan
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, United States
| | - Chase Carver
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, United States
| | - Timothy B Johnstone
- Department of Pharmacology, School of Medicine, University of California, Irvine, California, United States
| | - Derk J Hogenkamp
- Department of Pharmacology, School of Medicine, University of California, Irvine, California, United States
| | - Kelvin W Gee
- Department of Pharmacology, School of Medicine, University of California, Irvine, California, United States
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Chandel S, Gupta SK, Medhi B. Epileptogenesis following experimentally induced traumatic brain injury - a systematic review. Rev Neurosci 2018; 27:329-46. [PMID: 26581067 DOI: 10.1515/revneuro-2015-0050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 10/21/2015] [Indexed: 12/20/2022]
Abstract
Traumatic brain injury (TBI) is a complex neurotrauma in civilian life and the battlefield with a broad spectrum of symptoms, long-term neuropsychological disability, as well as mortality worldwide. Posttraumatic epilepsy (PTE) is a common outcome of TBI with unknown mechanisms, followed by posttraumatic epileptogenesis. There are numerous rodent models of TBI available with varying pathomechanisms of head injury similar to human TBI, but there is no evidence for an adequate TBI model that can properly mimic all aspects of clinical TBI and the first successive spontaneous focal seizures follow a single episode of neurotrauma with respect to epileptogenesis. This review aims to provide current information regarding the various experimental animal models of TBI relevant to clinical TBI. Mossy fiber sprouting, loss of dentate hilar neurons along with recurrent seizures, and epileptic discharge similar to human PTE have been studied in fluid percussion injury, weight-drop injury, and cortical impact models, but further refinement of animal models and functional test is warranted to better understand the underlying pathophysiology of posttraumatic epileptogenesis. A multifaceted research approach in TBI model may lead to exploration of the potential treatment measures, which are a major challenge to the research community and drug developers. With respect to clinical setting, proper patient data collection, improved clinical trials with advancement in drug delivery strategies, blood-brain barrier permeability, and proper monitoring of level and effects of target drug are also important.
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Magagna-Poveda A, Moretto JN, Scharfman HE. Increased gyrification and aberrant adult neurogenesis of the dentate gyrus in adult rats. Brain Struct Funct 2017; 222:4219-4237. [PMID: 28656372 PMCID: PMC5909844 DOI: 10.1007/s00429-017-1457-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 06/06/2017] [Indexed: 02/08/2023]
Abstract
A remarkable example of maladaptive plasticity is the development of epilepsy after a brain insult or injury to a normal animal or human. A structure that is considered central to the development of this type of epilepsy is the dentate gyrus (DG), because it is normally a relatively inhibited structure and its quiescence is thought to reduce hippocampal seizure activity. This characteristic of the DG is also considered to be important for normal hippocampal-dependent cognitive functions. It has been suggested that the brain insults which cause epilepsy do so because they cause the DG to be more easily activated. One type of brain insult that is commonly used is induction of severe seizures (status epilepticus; SE) by systemic injection of a convulsant drug. Here we describe an alteration in the DG after this type of experimental SE that may contribute to chronic seizures that has not been described before: large folds or gyri that develop in the DG by 1 month after SE. Large gyri appeared to increase network excitability because epileptiform discharges recorded in hippocampal slices after SE were longer in duration when recorded inside gyri relative to locations outside gyri. Large gyri may also increase excitability because immature adult-born neurons accumulated at the base of gyri with time after SE, and previous studies have suggested that abnormalities in adult-born DG neurons promote seizures after SE. In summary, large gyri after SE are a common finding in adult rats, show increased excitability, and are associated with the development of an abnormal spatial distribution of adult-born neurons. Together these alterations may contribute to chronic seizures and associated cognitive comorbidities after SE.
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Affiliation(s)
- Alejandra Magagna-Poveda
- The Nathan Kline Institute of Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd. Bldg. 35, Orangeburg, NY, 10962, USA
| | - Jillian N Moretto
- The Nathan Kline Institute of Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd. Bldg. 35, Orangeburg, NY, 10962, USA
| | - Helen E Scharfman
- The Nathan Kline Institute of Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd. Bldg. 35, Orangeburg, NY, 10962, USA.
- Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, One Park Ave., New York, NY, 10016, USA.
- Department of Physiology and Neuroscience, New York University Langone Medical Center, One Park Ave., New York, NY, 10016, USA.
- Department of Psychiatry, New York University Langone Medical Center, One Park Ave., New York, NY, 10016, USA.
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Samba Reddy D. Sex differences in the anticonvulsant activity of neurosteroids. J Neurosci Res 2017; 95:661-670. [PMID: 27870400 DOI: 10.1002/jnr.23853] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/21/2016] [Accepted: 07/06/2016] [Indexed: 12/11/2022]
Abstract
Epilepsy is one of the leading causes of chronic neurological morbidity worldwide. Acquired epilepsy may result from a number of conditions, such as brain injury, anoxia, tumors, stroke, neurotoxicity, and prolonged seizures. Sex differences have been observed in many seizure types; however, some sex-specific seizure disorders are much more prevalent in women. Despite some inconsistencies, substantial data indicates that sensitivity to seizure stimuli differs between the sexes. Men generally exhibit greater seizure susceptibility than women, whereas many women with epilepsy experience a cyclical occurrence of seizures that tends to center around the menstrual period, which has been termed catamenial epilepsy. Some epilepsy syndromes show gender differences with female predominance or male predominance. Steroid hormones, endogenous neurosteroids, and sexually dimorphic neural networks appear to play a key role in sex differences in seizure susceptibility. Neurosteroids, such as allopregnanolone, reflect sex differences in their anticonvulsant activity. This Review provides a brief overview of the evidence for sex differences in epilepsy and how sex differences influence the use of neurosteroids in epilepsy and epileptogenesis. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Sciences Center, College of Medicine, Bryan, Texas
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Bielefeld P, Mooney C, Henshall DC, Fitzsimons CP. miRNA-Mediated Regulation of Adult Hippocampal Neurogenesis; Implications for Epilepsy. Brain Plast 2017; 3:43-59. [PMID: 29765859 PMCID: PMC5928558 DOI: 10.3233/bpl-160036] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Hippocampal neural stem/progenitor cells (NSPCs) proliferate and differentiate to generate new neurons across the life span of most mammals, including humans. This process takes place within a characteristic local microenvironment where NSPCs interact with a variety of other cell types and encounter systemic regulatory factors. Within this microenvironment, cell intrinsic gene expression programs are modulated by cell extrinsic signals through complex interactions, in many cases involving short non-coding RNA molecules, such as miRNAs. Here we review the regulation of gene expression in NSPCs by miRNAs and its possible implications for epilepsy, which has been linked to alterations in adult hippocampal neurogenesis.
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Affiliation(s)
- Pascal Bielefeld
- Neuroscience Program, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, The Netherlands
| | - Catherine Mooney
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - David C. Henshall
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Carlos P. Fitzsimons
- Neuroscience Program, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, The Netherlands
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Abstract
This article highlights the emerging therapeutic potential of specific epigenetic modulators as promising antiepileptogenic or disease-modifying agents for curing epilepsy. Currently, there is an unmet need for antiepileptogenic agents that truly prevent the development of epilepsy in people at risk. There is strong evidence that epigenetic signaling, which exerts high fidelity regulation of gene expression, plays a crucial role in the pathophysiology of epileptogenesis and chronic epilepsy. These modifications are not hard-wired into the genome and are constantly reprogrammed by environmental influences. The potential epigenetic mechanisms, including histone modifications, DNA methylation, microRNA-based transcriptional control, and bromodomain reading activity, can drastically alter the neuronal gene expression profile by exerting their summative effects in a coordinated fashion. Such an epigenetic intervention appears more rational strategy for preventing epilepsy because it targets the primary pathway that initially triggers the numerous downstream cellular and molecular events mediating epileptogenesis. Among currently approved epigenetic drugs, the majority are anticancer drugs with well-established profiles in clinical trials and practice. Evidence from preclinical studies supports the premise that these drugs may be applied to a wide range of brain disorders. Targeting histone deacetylation by inhibiting histone deacetylase enzymes appears to be one promising epigenetic therapy since certain inhibitors have been shown to prevent epileptogenesis in animal models. However, developing neuronal specific epigenetic modulators requires rational, pathophysiology-based optimization to efficiently intercept the upstream pathways in epileptogenesis. Overall, epigenetic agents have been well positioned as new frontier tools towards the national goal of curing epilepsy.
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Affiliation(s)
- Iyan Younus
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, TX 77807, USA
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, TX 77807, USA.
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Interleukin-1 Receptor in Seizure Susceptibility after Traumatic Injury to the Pediatric Brain. J Neurosci 2017; 37:7864-7877. [PMID: 28724747 DOI: 10.1523/jneurosci.0982-17.2017] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/29/2017] [Accepted: 07/07/2017] [Indexed: 12/19/2022] Open
Abstract
Epilepsy after pediatric traumatic brain injury (TBI) is associated with poor quality of life. This study aimed to characterize post-traumatic epilepsy in a mouse model of pediatric brain injury, and to evaluate the role of interleukin-1 (IL-1) signaling as a target for pharmacological intervention. Male mice received a controlled cortical impact or sham surgery at postnatal day 21, approximating a toddler-aged child. Mice were treated acutely with an IL-1 receptor antagonist (IL-1Ra; 100 mg/kg, s.c.) or vehicle. Spontaneous and evoked seizures were evaluated from video-EEG recordings. Behavioral assays tested for functional outcomes, postmortem analyses assessed neuropathology, and brain atrophy was detected by ex vivo magnetic resonance imaging. At 2 weeks and 3 months post-injury, TBI mice showed an elevated seizure response to the convulsant pentylenetetrazol compared with sham mice, associated with abnormal hippocampal mossy fiber sprouting. A robust increase in IL-1β and IL-1 receptor were detected after TBI. IL-1Ra treatment reduced seizure susceptibility 2 weeks after TBI compared with vehicle, and a reduction in hippocampal astrogliosis. In a chronic study, IL-1Ra-TBI mice showed improved spatial memory at 4 months post-injury. At 5 months, most TBI mice exhibited spontaneous seizures during a 7 d video-EEG recording period. At 6 months, IL-1Ra-TBI mice had fewer evoked seizures compared with vehicle controls, coinciding with greater preservation of cortical tissue. Findings demonstrate this model's utility to delineate mechanisms underlying epileptogenesis after pediatric brain injury, and provide evidence of IL-1 signaling as a mediator of post-traumatic astrogliosis and seizure susceptibility.SIGNIFICANCE STATEMENT Epilepsy is a common cause of morbidity after traumatic brain injury in early childhood. However, a limited understanding of how epilepsy develops, particularly in the immature brain, likely contributes to the lack of efficacious treatments. In this preclinical study, we first demonstrate that a mouse model of traumatic injury to the pediatric brain reproduces many neuropathological and seizure-like hallmarks characteristic of epilepsy. Second, we demonstrate that targeting the acute inflammatory response reduces cognitive impairments, the degree of neuropathology, and seizure susceptibility, after pediatric brain injury in mice. These findings provide evidence that inflammatory cytokine signaling is a key process underlying epilepsy development after an acquired brain insult, which represents a feasible therapeutic target to improve quality of life for survivors.
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Jiruska P, Alvarado-Rojas C, Schevon CA, Staba R, Stacey W, Wendling F, Avoli M. Update on the mechanisms and roles of high-frequency oscillations in seizures and epileptic disorders. Epilepsia 2017; 58:1330-1339. [PMID: 28681378 DOI: 10.1111/epi.13830] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2017] [Indexed: 12/11/2022]
Abstract
High-frequency oscillations (HFOs) are a type of brain activity that is recorded from brain regions capable of generating seizures. Because of the close association of HFOs with epileptogenic tissue and ictogenesis, understanding their cellular and network mechanisms could provide valuable information about the organization of epileptogenic networks and how seizures emerge from the abnormal activity of these networks. In this review, we summarize the most recent advances in the field of HFOs and provide a critical evaluation of new observations within the context of already established knowledge. Recent improvements in recording technology and the introduction of optogenetics into epilepsy research have intensified experimental work on HFOs. Using advanced computer models, new cellular substrates of epileptic HFOs were identified and the role of specific neuronal subtypes in HFO genesis was determined. Traditionally, the pathogenesis of HFOs was explored mainly in patients with temporal lobe epilepsy and in animal models mimicking this condition. HFOs have also been reported to occur in other epileptic disorders and models such as neocortical epilepsy, genetically determined epilepsies, and infantile spasms, which further support the significance of HFOs in the pathophysiology of epilepsy. It is increasingly recognized that HFOs are generated by multiple mechanisms at both the cellular and network levels. Future studies on HFOs combining novel high-resolution in vivo imaging techniques and precise control of neuronal behavior using optogenetics or chemogenetics will provide evidence about the causal role of HFOs in seizures and epileptogenesis. Detailed understanding of the pathophysiology of HFOs will propel better HFO classification and increase their information yield for clinical and diagnostic purposes.
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Affiliation(s)
- Premysl Jiruska
- Department of Developmental Epileptology, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | | | | | - Richard Staba
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, U.S.A
| | - William Stacey
- Department of Neurology, Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, U.S.A
| | - Fabrice Wendling
- Laboratory of Signal and Image Processing, INSERM U1099, Rennes, France.,Laboratoire de Traitement du Signal et de l'Image, University of Rennes 1, Rennes, France
| | - Massimo Avoli
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, Québec, Canada.,Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
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Sick T, Wasserman J, Bregy A, Sick J, Dietrich WD, Bramlett HM. Increased Expression of Epileptiform Spike/Wave Discharges One Year after Mild, Moderate, or Severe Fluid Percussion Brain Injury in Rats. J Neurotrauma 2017; 34:2467-2474. [PMID: 28388862 DOI: 10.1089/neu.2016.4826] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In this study, we describe increased expression of cortical epileptiform spike/wave discharges (SWD) in rats one year after mild, moderate, or severe fluid percussion traumatic brain injury (fpTBI). Groups of rats consisted of animals that had received mild, moderate, or severe fpTBI, or sham operation one year earlier than electrocorticography (ECoG) recordings. In addition, we included a group of age-matched naïve animals. ECoG was recorded from awake animals using epidural electrodes implanted on the injured hemisphere (right), sham-operated hemisphere (right), or right hemisphere in naïve animals. The SWDs were detected automatically using Fast Fourier Transformation and a novel algorithm for comparing changes in spectral power to control (nonepileptical) ECoG. The fpTBI resulted in increased expression of SWDs one year after injury compared with sham-operated or naïve animals. The number of SWD-containing ECoG epochs recorded in a 1 h recording session were: naïve 12.9 ± 10.3, n = 8, sham 23.6 ± 8.2, n = 10, mild TBI 78.9 ± 23.9, n = 10, moderate TBI 61.3 ± 32.5, n = 12, severe TBI 72.5 ± 28.3, n = 11 (mean ± standard error of the mean). Increased expression of SWDs was not related to injury severity. SWDs were observed to a lesser extent even in sham-operated and naïve animals. The data indicate that fpTBI exacerbates expression of SWDs in the rat and that this increase may be observed at least one year after injury. As others have discussed, the spontaneous occurrence of these epileptiform events in rodents limits the use of this model for investigations of acquired epilepsy, at least of the nonconvulsive type, after TBI.
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Affiliation(s)
- Thomas Sick
- 1 The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine , Miami, Florida
- 2 Department of Neurology, University of Miami Miller School of Medicine , Miami, Florida
- 3 Department of Neuroscience Program, University of Miami Miller School of Medicine , Miami, Florida
| | - Joseph Wasserman
- 1 The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine , Miami, Florida
| | - Amade Bregy
- 1 The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine , Miami, Florida
| | - Justin Sick
- 1 The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine , Miami, Florida
| | - W Dalton Dietrich
- 1 The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine , Miami, Florida
- 2 Department of Neurology, University of Miami Miller School of Medicine , Miami, Florida
- 3 Department of Neuroscience Program, University of Miami Miller School of Medicine , Miami, Florida
- 4 Department of Neurological Surgery, University of Miami Miller School of Medicine , Miami, Florida
| | - Helen M Bramlett
- 1 The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine , Miami, Florida
- 2 Department of Neurology, University of Miami Miller School of Medicine , Miami, Florida
- 3 Department of Neuroscience Program, University of Miami Miller School of Medicine , Miami, Florida
- 4 Department of Neurological Surgery, University of Miami Miller School of Medicine , Miami, Florida
- 5 Bruce W. Carter Department of Veterans Affairs Medical Center , Miami, Florida
- 6 Center for Computational Science, University of Miami , Miami, Florida
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Clossen BL, Reddy DS. Novel therapeutic approaches for disease-modification of epileptogenesis for curing epilepsy. Biochim Biophys Acta Mol Basis Dis 2017; 1863:1519-1538. [PMID: 28179120 PMCID: PMC5474195 DOI: 10.1016/j.bbadis.2017.02.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/31/2017] [Accepted: 02/03/2017] [Indexed: 11/16/2022]
Abstract
This article describes the recent advances in epileptogenesis and novel therapeutic approaches for the prevention of epilepsy, with a special emphasis on the pharmacological basis of disease-modification of epileptogenesis for curing epilepsy. Here we assess animal studies and human clinical trials of epilepsy spanning 1982-2016. Epilepsy arises from a number of neuronal factors that trigger epileptogenesis, which is the process by which a brain shifts from a normal physiologic state to an epileptic condition. The events precipitating these changes can be of diverse origin, including traumatic brain injury, cerebrovascular damage, infections, chemical neurotoxicity, and emergency seizure conditions such as status epilepticus. Expectedly, the molecular and system mechanisms responsible for epileptogenesis are not well defined or understood. To date, there is no approved therapy for the prevention of epilepsy. Epigenetic dysregulation, neuroinflammation, and neurodegeneration appear to trigger epileptogenesis. Targeted drugs are being identified that can truly prevent the development of epilepsy in at-risk people. The promising agents include rapamycin, COX-2 inhibitors, TRK inhibitors, epigenetic modulators, JAK-STAT inhibitors, and neurosteroids. Recent evidence suggests that neurosteroids may play a role in modulating epileptogenesis. A number of promising drugs are under investigation for the prevention or modification of epileptogenesis to halt the development of epilepsy. Some drugs in development appear rational for preventing epilepsy because they target the initial trigger or related signaling pathways as the brain becomes progressively more prone to seizures. Additional research into the target validity and clinical investigation is essential to make new frontiers in curing epilepsy.
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Affiliation(s)
- Bryan L Clossen
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA.
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Abstract
The epileptic encephalopathies are severe and often treatment-resistant conditions that are associated with a progressive disturbance of brain function, resulting in a broad range of neurological and non-neurological comorbidities. The concept of epileptic encephalopathies entails that the encephalopathy aspect of the overall condition is primarily driven by the epileptic activity of the disease, which often manifests as specific and pathological features on the electroencephalogram. Genetic factors in epileptic encephalopathies are increasingly recognized. As of 2016, more than 30 genes have been securely implicated as causative genes for genetic epileptic encephalopathies. Even though the traditional concept of epileptic encephalopathies entails that the progressive disturbance of brain dysfunction is primarily due to the abnormal hypersynchronous activity that underlies the seizure disorders, this strict concept rarely holds true for patients with identified genetic etiologies. More commonly, an underlying genetic etiology is thought to predispose both to the neurodevelopmental comorbidities and to the seizure phenotype with a complex interaction between both. In this chapter, we will elucidate to what extent neurodegeneration rather than epilepsy-related regression is a feature of the common epileptic encephalopathies, drawing parallels between two relatively separate fields of neurogenetic research.
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Uriarte A, Maestro Saiz I. Canine versus human epilepsy: are we up to date? J Small Anim Pract 2016; 57:115-21. [PMID: 26931499 DOI: 10.1111/jsap.12437] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/21/2015] [Accepted: 08/13/2015] [Indexed: 02/04/2023]
Abstract
In this paper we analyse and compare features of canine and human epilepsy and we suggest new tools for better future understanding of canine epilepsy. The prevalence of epileptic seizures in dogs ranges between 0.5% and 5.7% and between 1% and 3% in the human population. Studies on human epilepsy provide a ready-made format for classification, diagnosis and treatment in veterinary epilepsy. Human studies highlight the value of a thorough seizure classification. Nevertheless, a matter of concern in canine epilepsy is the limited information regarding seizure description and classification because of the lack of EEG-video recording. Establishment of a consensus protocol for ambulatory home video-recording in dogs who suffer from epilepsy, mainly considering indications, duration of monitoring, the sufficient essential training for an optimal interpretation of ictal semiology and the methodology of recordings is needed. The ultimate goal is that the information gathered by these videos will be analysed to describe the epileptic seizures thoroughly, recognize patterns and move towards a better understanding and therefore classification of canine epileptic seizures.
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Affiliation(s)
- A Uriarte
- North Down Specialist Referrals, Surrey, RH1 4QP
| | - I Maestro Saiz
- Clinical Neurophysiology Department, Cruces University Hospital, Barakaldo, Biscay, 48903, Spain
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Itoh K, Ishihara Y, Komori R, Nochi H, Taniguchi R, Chiba Y, Ueno M, Takata-Tsuji F, Dohgu S, Kataoka Y. Levetiracetam treatment influences blood-brain barrier failure associated with angiogenesis and inflammatory responses in the acute phase of epileptogenesis in post-status epilepticus mice. Brain Res 2016; 1652:1-13. [PMID: 27693413 DOI: 10.1016/j.brainres.2016.09.038] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 09/09/2016] [Accepted: 09/26/2016] [Indexed: 12/18/2022]
Abstract
Our previous study showed that treatment with levetiracetam (LEV) after status epilepticus (SE) termination by diazepam might prevent the development of spontaneous recurrent seizures via the inhibition of neurotoxicity induced by brain edema events. In the present study, we determined the possible molecular and cellular mechanisms of LEV treatment after termination of SE. To assess the effect of LEV against the brain alterations after SE, we focused on blood-brain barrier (BBB) dysfunction associated with angiogenesis and brain inflammation. The consecutive treatment of LEV inhibited the temporarily increased BBB leakage in the hippocampus two days after SE. At the same time point, the LEV treatment significantly inhibited the increase in the number of CD31-positive endothelial immature cells and in the expression of angiogenic factors. These findings suggested that the increase in neovascularization led to an increase in BBB permeability by SE-induced BBB failure, and these brain alterations were prevented by LEV treatment. Furthermore, in the acute phase of the latent period, pro-inflammatory responses for epileptogenic targets in microglia and astrocytes of the hippocampus activated, and these upregulations of pro-inflammatory-related molecules were inhibited by LEV treatment. These findings suggest that LEV is likely involved in neuroprotection via anti-angiogenesis and anti-inflammatory activities against BBB dysfunction in the acute phase of epileptogenesis after SE.
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Affiliation(s)
- Kouichi Itoh
- Laboratory for Pharmacotherapy and Experimental Neurology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa 769-2193, Japan.
| | - Yasuhiro Ishihara
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima 739-8521, Japan
| | - Rie Komori
- Laboratory for Pharmacotherapy and Experimental Neurology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa 769-2193, Japan
| | - Hiromi Nochi
- Laboratory for Pharmaceutical Health Sciences, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Kagawa 769-2193, Japan
| | - Ruri Taniguchi
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima 739-8521, Japan
| | - Yoichi Chiba
- Department of Pathology and Host Defense, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan
| | - Masaki Ueno
- Department of Pathology and Host Defense, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan
| | - Fuyuko Takata-Tsuji
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka 814-0180, Japan
| | - Shinya Dohgu
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka 814-0180, Japan
| | - Yasufumi Kataoka
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka 814-0180, Japan
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Brandt C, Rankovic V, Töllner K, Klee R, Bröer S, Löscher W. Refinement of a model of acquired epilepsy for identification and validation of biomarkers of epileptogenesis in rats. Epilepsy Behav 2016; 61:120-131. [PMID: 27343814 DOI: 10.1016/j.yebeh.2016.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/09/2016] [Accepted: 05/12/2016] [Indexed: 01/23/2023]
Abstract
In rodent models in which status epilepticus (SE) is used to induce epilepsy, typically most animals develop spontaneous recurrent seizures (SRS). The SE duration for induction of epileptogenesis depends on the type of SE induction. In models with electrical SE induction, the minimum duration of SE to induce epileptogenesis in >90% of animals ranges from 3-4h. A high incidence of epilepsy is an advantage in the search of antiepileptogenic treatments, whereas it is a disadvantage in the search for biomarkers of epileptogenesis, because it does not allow a comparison of potential biomarkers in animals that either develop or do not develop epilepsy. The aim of this project was the refinement of an established SE rat model so that only ~50% of the animals develop epilepsy. For this purpose, we used an electrical model of SE induction, in which a self-sustained SE develops after prolonged stimulation of the basolateral amygdala. Previous experiments had shown that the majority of rats develop SRS after 4-h SE in this model so that the SE reduced duration to 2.5h by administering diazepam. This resulted in epilepsy development in only 50% of rats, thus reaching the goal of the project. The latent period to onset of SRS wa s >2weeks in most rats. Development of epilepsy could be predicted in most rats by behavioral hyperexcitability, whereas seizure threshold did not differentiate rats that did and did not develop SRS. The refined SE model may offer a platform to identify and validate biomarkers of epileptogenesis.
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Affiliation(s)
- Claudia Brandt
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Vladan Rankovic
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Kathrin Töllner
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Rebecca Klee
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Sonja Bröer
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
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Ostergard T, Sweet J, Kusyk D, Herring E, Miller J. Animal models of post-traumatic epilepsy. J Neurosci Methods 2016; 272:50-55. [PMID: 27044802 DOI: 10.1016/j.jneumeth.2016.03.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 03/31/2016] [Indexed: 10/22/2022]
Abstract
Post-traumatic epilepsy (PTE) is defined as the development of unprovoked seizures in a delayed fashion after traumatic brain injury (TBI). PTE lies at the intersection of two distinct fields of study, epilepsy and neurotrauma. TBI is associated with a myriad of both focal and diffuse anatomic injuries, and an ideal animal model of epilepsy after TBI must mimic the characteristics of human PTE. The three most commonly used models of TBI are lateral fluid percussion, controlled cortical injury, and weight drop. Much of what is known about PTE has resulted from use of these models. In this review, we describe the most commonly used animal models of TBI with special attention to their advantages and disadvantages with respect to their use as a model of PTE.
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Affiliation(s)
- Thomas Ostergard
- The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Jennifer Sweet
- The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Dorian Kusyk
- The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Eric Herring
- The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Jonathan Miller
- The Neurological Institute, University Hospital Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States.
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Murugan M, Santhakumar V, Kannurpatti SS. Facilitating Mitochondrial Calcium Uptake Improves Activation-Induced Cerebral Blood Flow and Behavior after mTBI. Front Syst Neurosci 2016; 10:19. [PMID: 27013987 PMCID: PMC4782040 DOI: 10.3389/fnsys.2016.00019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 02/19/2016] [Indexed: 11/13/2022] Open
Abstract
Mild to moderate traumatic brain injury (mTBI) leads to secondary neuronal loss via excitotoxic mechanisms, including mitochondrial Ca(2+) overload. However, in the surviving cellular population, mitochondrial Ca(2+) influx, and oxidative metabolism are diminished leading to suboptimal neuronal circuit activity and poor prognosis. Hence we tested the impact of boosting neuronal electrical activity and oxidative metabolism by facilitating mitochondrial Ca(2+) uptake in a rat model of mTBI. In developing rats (P25-P26) sustaining an mTBI, we demonstrate post-traumatic changes in cerebral blood flow (CBF) in the sensorimotor cortex in response to whisker stimulation compared to sham using functional Laser Doppler Imaging (fLDI) at adulthood (P67-P73). Compared to sham, whisker stimulation-evoked positive CBF responses decreased while negative CBF responses increased in the mTBI animals. The spatiotemporal CBF changes representing underlying neuronal activity suggested profound changes to neurovascular activity after mTBI. Behavioral assessment of the same cohort of animals prior to fLDI showed that mTBI resulted in persistent contralateral sensorimotor behavioral deficit along with ipsilateral neuronal loss compared to sham. Treating mTBI rats with Kaempferol, a dietary flavonol compound that enhanced mitochondrial Ca(2+) uptake, eliminated the inter-hemispheric asymmetry in the whisker stimulation-induced positive CBF responses and the ipsilateral negative CBF responses otherwise observed in the untreated and vehicle-treated mTBI animals in adulthood. Kaempferol also improved somatosensory behavioral measures compared to untreated and vehicle treated mTBI animals without augmenting post-injury neuronal loss. The results indicate that reduced mitochondrial Ca(2+) uptake in the surviving populations affect post-traumatic neural activation leading to persistent behavioral deficits. Improvement in sensorimotor behavior and spatiotemporal neurovascular activity following kaempferol treatment suggests that facilitation of mitochondrial Ca(2+) uptake in the early window after injury may sustain optimal neural activity and metabolism and contribute to improved function of the surviving cellular populations after mTBI.
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Affiliation(s)
- Madhuvika Murugan
- Department of Radiology, Rutgers New Jersey Medical School Newark, NJ, USA
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School Newark, NJ, USA
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Posttraumatic seizures and epilepsy in adult rats after controlled cortical impact. Epilepsy Res 2015; 117:104-16. [PMID: 26432760 DOI: 10.1016/j.eplepsyres.2015.09.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 08/26/2015] [Accepted: 09/10/2015] [Indexed: 12/27/2022]
Abstract
Posttraumatic epilepsy (PTE) has been modeled with different techniques of experimental traumatic brain injury (TBI) using mice and rats at various ages. We hypothesized that the technique of controlled cortical impact (CCI) could be used to establish a model of PTE in young adult rats. A total of 156 male Sprague-Dawley rats of 2-3 months of age (128 CCI-injured and 28 controls) was used for monitoring and/or anatomical studies. Provoked class 3-5 seizures were recorded by video monitoring in 7/57 (12.3%) animals in the week immediately following CCI of the right parietal cortex; none of the 7 animals demonstrated subsequent spontaneous convulsive seizures. Monitoring with video and/or video-EEG was performed on 128 animals at various time points 8-619 days beyond one week following CCI during which 26 (20.3%) demonstrated nonconvulsive or convulsive epileptic seizures. Nonconvulsive epileptic seizures of >10s were demonstrated in 7/40 (17.5%) animals implanted with 2 or 3 depth electrodes and usually characterized by an initial change in behavior (head raising or animal alerting) followed by motor arrest during an ictal discharge that consisted of high-amplitude spikes or spike-waves with frequencies ranging between 1 and 2Hz class 3-5 epileptic seizures were recorded by video monitoring in 17/88 (19%) and by video-EEG in 2/40 (5%) CCI-injured animals. Ninety of 156 (58%) animals (79 CCI-injured, 13 controls) underwent transcardial perfusion for gross and microscopic studies. CCI caused severe brain tissue loss and cavitation of the ipsilateral cerebral hemisphere associated with cell loss in the hippocampal CA1 and CA3 regions, hilus, and dentate granule cells, and thalamus. All Timm-stained CCI-injured brains demonstrated ipsilateral hippocampal mossy fiber sprouting in the inner molecular layer. These results indicate that the CCI model of TBI in adult rats can be used to study the structure-function relationships that underlie epileptogenesis and PTE.
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Forecasting Seizures Using Intracranial EEG Measures and SVM in Naturally Occurring Canine Epilepsy. PLoS One 2015; 10:e0133900. [PMID: 26241907 PMCID: PMC4524640 DOI: 10.1371/journal.pone.0133900] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 07/02/2015] [Indexed: 12/02/2022] Open
Abstract
Management of drug resistant focal epilepsy would be greatly assisted by a reliable warning system capable of alerting patients prior to seizures to allow the patient to adjust activities or medication. Such a system requires successful identification of a preictal, or seizure-prone state. Identification of preictal states in continuous long- duration intracranial electroencephalographic (iEEG) recordings of dogs with naturally occurring epilepsy was investigated using a support vector machine (SVM) algorithm. The dogs studied were implanted with a 16-channel ambulatory iEEG recording device with average channel reference for a mean (st. dev.) of 380.4 (+87.5) days producing 220.2 (+104.1) days of intracranial EEG recorded at 400 Hz for analysis. The iEEG records had 51.6 (+52.8) seizures identified, of which 35.8 (+30.4) seizures were preceded by more than 4 hours of seizure-free data. Recorded iEEG data were stratified into 11 contiguous, non-overlapping frequency bands and binned into one-minute synchrony features for analysis. Performance of the SVM classifier was assessed using a 5-fold cross validation approach, where preictal training data were taken from 90 minute windows with a 5 minute pre-seizure offset. Analysis of the optimal preictal training time was performed by repeating the cross validation over a range of preictal windows and comparing results. We show that the optimization of feature selection varies for each subject, i.e. algorithms are subject specific, but achieve prediction performance significantly better than a time-matched Poisson random predictor (p<0.05) in 5/5 dogs analyzed.
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Epilepsy After Resolution of Presumed Childhood Encephalitis. Pediatr Neurol 2015; 53:65-72. [PMID: 26092415 DOI: 10.1016/j.pediatrneurol.2015.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 03/13/2015] [Accepted: 03/14/2015] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To evaluate factors associated with the development of epilepsy after resolution of presumed childhood encephalitis. METHODS A total of 217 patients with suspected encephalitis who met criteria for the California Encephalitis Project were identified. Evaluable outcome information was available for 99 patients (40 girls, 59 boys, ages 2 months to 17 years) without preexisting neurological conditions, including prior seizures or abnormal brain magnetic resonance imaging scans. We identified factors correlated with the development of epilepsy after resolution of the acute illness. RESULTS Development of epilepsy was correlated with the initial presenting sign of seizure (P < 0.001). With each additional antiepileptic drug used to control seizures, the odds ratio of developing epilepsy was increased twofold (P < 0.001). An abnormal electroencephalograph (P < 0.05) and longer hospital duration (median of 8 versus 21 days) also correlated with development of epilepsy (P < 0.01). The need for medically induced coma was associated with epilepsy (P < 0.001). Seizures in those patients were particularly refractory, often requiring longer than 24 hours to obtain seizure control. Individuals who required antiepileptic drugs at discharge (P < 0.001) or were readmitted after their acute illness (P < 0.001) were more likely to develop epilepsy. Of our patients who were able to wean antiepileptic drugs after being started during hospitalization, 42% were successfully tapered off within 6 months. CONCLUSIONS Limited data are available on the risk of developing epilepsy after childhood encephalitis. This is the first study that not only identifies risk factors for the development of epilepsy, but also provides data regarding the success rate of discontinuing antiepileptic medication after resolution of encephalitis.
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