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Wen X, Otoo MN, Tang J, Brothers T, Ward KE, Asal N, Meador KJ. Angiotensin Receptor Blockers for Hypertension and Risk of Epilepsy. JAMA Neurol 2024; 81:866-874. [PMID: 38884986 PMCID: PMC11184499 DOI: 10.1001/jamaneurol.2024.1714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 04/19/2024] [Indexed: 06/18/2024]
Abstract
Importance Animal and human studies have suggested that the use of angiotensin receptor blockers (ARBs) may be associated with a lower risk of incident epilepsy compared with other antihypertensive medications. However, observational data from the US are lacking. Objective To evaluate the association between ARB use and epilepsy incidence in subgroups of US patients with hypertension. Design, Setting, and Participants This retrospective cohort study used data from a national health administrative database from January 2010 to December 2017 with propensity score (PS) matching. The eligible cohort included privately insured individuals aged 18 years or older with diagnosis of primary hypertension and dispensed at least 1 ARB, angiotensin-converting enzyme inhibitor (ACEI), β-blocker, or calcium channel blocker (CCB) from 2010 to 2017. Patients with a diagnosis of epilepsy at or before the index date or dispensed an antiseizure medication 12 months before or 90 days after initiating the study medications were excluded. The data analysis for this project was conducted from April 2022 to April 2024. Exposures Propensity scores were generated based on baseline covariates and used to match patients who received ARBs with those who received either ACEIs, β-blockers, CCBs, or a combination of these antihypertensive medications. Main Outcomes and Measures Cox regression analyses were used to evaluate epilepsy incidence during follow-up comparing the ARB cohort with other antihypertensive classes. Subgroup and sensitivity analyses were conducted to examine the association between ARB use and epilepsy incidence in various subgroups. Results Of 2 261 964 patients (mean [SD] age, 61.7 [13.9] years; 1 120 630 [49.5%] female) included, 309 978 received ARBs, 807 510 received ACEIs, 695 887 received β-blockers, and 448 589 received CCBs. Demographic and clinical characteristics differed across the 4 comparison groups prior to PS matching. Compared with ARB users, patients receiving ACEIs were predominantly male and had diabetes, CCB users were generally older (eg, >65 years), and β-blocker users had more comorbidities and concurrent medications. The 1:1 PS-matched subgroups included 619 858 patients for ARB vs ACEI, 619 828 patients for ARB vs β-blocker, and 601 002 patients for ARB vs CCB. Baseline characteristics were equally distributed between comparison groups after matching with propensity scores. Use of ARBs was associated with a decreased incidence of epilepsy compared with ACEIs (adjusted hazard ratio [aHR], 0.75; 95% CI, 0.58-0.96), β-blockers (aHR, 0.70; 95% CI, 0.54-0.90), and a combination of other antihypertensive classes (aHR, 0.72; 95% CI, 0.56-0.95). Subgroup analyses revealed a significant association between ARB use (primarily losartan) and epilepsy incidence in patients with no preexisting history of stroke or cardiovascular disease. Conclusions and Relevance This cohort study found that ARBs, mainly losartan, were associated with a lower incidence of epilepsy compared with other antihypertensive agents in hypertensive patients with no preexisting stroke or cardiovascular disease. Further studies, such as randomized clinical trials, are warranted to confirm the comparative antiepileptogenic properties of antihypertensive medications.
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Affiliation(s)
- Xuerong Wen
- Department of Pharmacy Practice and Clinical Research, College of Pharmacy, University of Rhode Island, Kingston
| | - Marianne N. Otoo
- Department of Pharmacy Practice and Clinical Research, College of Pharmacy, University of Rhode Island, Kingston
| | - Jie Tang
- Department of Nephrology, The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Todd Brothers
- Department of Pharmacy Practice and Clinical Research, College of Pharmacy, University of Rhode Island, Kingston
| | - Kristina E. Ward
- Department of Pharmacy Practice and Clinical Research, College of Pharmacy, University of Rhode Island, Kingston
| | - Nicole Asal
- Department of Pharmacy Practice and Clinical Research, College of Pharmacy, University of Rhode Island, Kingston
| | - Kimford J. Meador
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Palo Alto, California
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Danačíková Š, Straka B, Daněk J, Kořínek V, Otáhal J. In vitro human cell culture models in a bench-to-bedside approach to epilepsy. Epilepsia Open 2024; 9:865-890. [PMID: 38637998 PMCID: PMC11145627 DOI: 10.1002/epi4.12941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/05/2024] [Accepted: 03/31/2024] [Indexed: 04/20/2024] Open
Abstract
Epilepsy is the most common chronic neurological disease, affecting nearly 1%-2% of the world's population. Current pharmacological treatment and regimen adjustments are aimed at controlling seizures; however, they are ineffective in one-third of the patients. Although neuronal hyperexcitability was previously thought to be mainly due to ion channel alterations, current research has revealed other contributing molecular pathways, including processes involved in cellular signaling, energy metabolism, protein synthesis, axon guidance, inflammation, and others. Some forms of drug-resistant epilepsy are caused by genetic defects that constitute potential targets for precision therapy. Although such approaches are increasingly important, they are still in the early stages of development. This review aims to provide a summary of practical aspects of the employment of in vitro human cell culture models in epilepsy diagnosis, treatment, and research. First, we briefly summarize the genetic testing that may result in the detection of candidate pathogenic variants in genes involved in epilepsy pathogenesis. Consequently, we review existing in vitro cell models, including induced pluripotent stem cells and differentiated neuronal cells, providing their specific properties, validity, and employment in research pipelines. We cover two methodological approaches. The first approach involves the utilization of somatic cells directly obtained from individual patients, while the second approach entails the utilization of characterized cell lines. The models are evaluated in terms of their research and clinical benefits, relevance to the in vivo conditions, legal and ethical aspects, time and cost demands, and available published data. Despite the methodological, temporal, and financial demands of the reviewed models they possess high potential to be used as robust systems in routine testing of pathogenicity of detected variants in the near future and provide a solid experimental background for personalized therapy of genetic epilepsies. PLAIN LANGUAGE SUMMARY: Epilepsy affects millions worldwide, but current treatments fail for many patients. Beyond traditional ion channel alterations, various genetic factors contribute to the disorder's complexity. This review explores how in vitro human cell models, either from patients or from cell lines, can aid in understanding epilepsy's genetic roots and developing personalized therapies. While these models require further investigation, they offer hope for improved diagnosis and treatment of genetic forms of epilepsy.
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Affiliation(s)
- Šárka Danačíková
- Laboratory of Developmental EpileptologyInstitute of Physiology of the Czech Academy of SciencesPragueCzech Republic
- Department of Pathophysiology, Second Faculty of MedicineCharles UniversityPragueCzech Republic
- Laboratory of Cell and Developmental BiologyInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
- Department of Physiology, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Barbora Straka
- Neurogenetics Laboratory of the Department of Paediatric Neurology, Second Faculty of MedicineCharles University and Motol University Hospital, Full Member of the ERN EpiCAREPragueCzech Republic
| | - Jan Daněk
- Laboratory of Developmental EpileptologyInstitute of Physiology of the Czech Academy of SciencesPragueCzech Republic
| | - Vladimír Kořínek
- Laboratory of Cell and Developmental BiologyInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
| | - Jakub Otáhal
- Laboratory of Developmental EpileptologyInstitute of Physiology of the Czech Academy of SciencesPragueCzech Republic
- Department of Pathophysiology, Second Faculty of MedicineCharles UniversityPragueCzech Republic
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Bryson A, Mendis D, Morrisroe E, Reid CA, Halgamuge S, Petrou S. Classification of antiseizure drugs in cultured neuronal networks using multielectrode arrays and unsupervised learning. Epilepsia 2022; 63:1693-1703. [PMID: 35460272 DOI: 10.1111/epi.17268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/20/2022] [Accepted: 04/21/2022] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Antiseizure drugs (ASDs) modulate synaptic and ion channel function to prevent abnormal hypersynchronous or excitatory activity arising in neuronal networks, but the relationship between ASDs with respect to their impact on network activity is poorly defined. In this study, we first investigated whether different ASD classes exert differential impact upon network activity, and we then sought to classify ASDs according to their impact on network activity. METHODS We used multielectrode arrays (MEAs) to record the network activity of cultured cortical neurons after applying ASDs from two classes: sodium channel blockers (SCBs) and γ-aminobutyric acid type A receptor-positive allosteric modulators (GABA PAMs). A two-dimensional representation of changes in network features was then derived, and the ability of this low-dimensional representation to classify ASDs with different molecular targets was assessed. RESULTS A two-dimensional representation of network features revealed a separation between the SCB and GABA PAM drug classes, and could classify several test compounds known to act through these molecular targets. Interestingly, several ASDs with novel targets, such as cannabidiol and retigabine, had closer similarity to the SCB class with respect to their impact upon network activity. SIGNIFICANCE These results demonstrate that the molecular target of two common classes of ASDs is reflected through characteristic changes in network activity of cultured neurons. Furthermore, a low-dimensional representation of network features can be used to infer an ASDs molecular target. This approach may allow for drug screening to be performed based on features extracted from MEA recordings.
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Affiliation(s)
- Alexander Bryson
- Ion Channels and Diseases Group, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Department of Neurology, Austin Health, Heidelberg, Victoria, Australia
| | | | - Emma Morrisroe
- Ion Channels and Diseases Group, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Christopher A Reid
- Ion Channels and Diseases Group, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Saman Halgamuge
- Department of Mechanical Engineering, School of Electrical, Mechanical, and Infrastructure Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Steven Petrou
- Ion Channels and Diseases Group, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
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Feldman RE, Marcuse LV, Verma G, Brown SSG, Rus A, Rutland JW, Delman BN, Balchandani P, Fields MC. Seven-tesla susceptibility-weighted analysis of hippocampal venous structures: Application to magnetic-resonance-normal focal epilepsy. Epilepsia 2020; 61:287-296. [PMID: 32020606 DOI: 10.1111/epi.16433] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 01/01/2020] [Accepted: 01/01/2020] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Vascular structures may play a significant role in epileptic pathology. Although previous attempts to characterize vasculature relative to epileptogenic zones and hippocampal sclerosis have been inconsistent, an in vivo method of analysis would assist in resolving these inconsistencies and facilitate a comparison against healthy controls in a human model. Magnetic resonance imaging is a noninvasive technique that provides excellent soft tissue contrast, and the relatively recent development of susceptibility-weighted imaging has dramatically improved the visibility of small veins. METHODS We built and tested a Hessian-based segmentation technique, which takes advantage of the increased signal and contrast available at 7 T to detect venous structures in vivo. We investigate the ability of this technique to quantify vessels in the brain and apply it to an asymmetry analysis of vessel density in the hippocampus in patients with mesial temporal lobe epilepsy (MTLE) and neocortical epilepsy. RESULTS Vessel density was highly symmetric in the hippocampus in controls (mean asymmetry = 0.080 ± 0.076, median = 0.05027), whereas average vessel density asymmetry was greater in neocortical (mean asymmetry = 0.23 ± 0.17, median = 0.14) and MTLE (mean asymmetry = 0.37 ± 0.46, median = 0.26) patients, with the decrease in vessel density ipsilateral to the suspected seizure onset zone. Post hoc testing with one-way analysis of variance and Tukey post hoc test indicated significant differences in the group means (P < .02) between MTLE and the control group only. SIGNIFICANCE Asymmetry in vessel density in the hippocampus is visible in patients with MTLE, even when qualitative and quantitative measures of hippocampal asymmetry show little volumetric difference between epilepsy patients and healthy controls.
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Affiliation(s)
- Rebecca Emily Feldman
- Department of Computer Science, Math, Physics, and Statistics, University of British Columbia, Kelowna, British Columbia, Canada.,Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York
| | | | - Gaurav Verma
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York
| | | | - Alexandru Rus
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - John Watson Rutland
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Bradley Neil Delman
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Priti Balchandani
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York
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Ghosh C, Hossain M, Solanki J, Dadas A, Marchi N, Janigro D. Pathophysiological implications of neurovascular P450 in brain disorders. Drug Discov Today 2016; 21:1609-1619. [PMID: 27312874 DOI: 10.1016/j.drudis.2016.06.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/14/2016] [Accepted: 06/06/2016] [Indexed: 01/12/2023]
Abstract
Over the past decades, the significance of cytochrome P450 (CYP) enzymes has expanded beyond their role as peripheral drug metabolizers in the liver and gut. CYP enzymes are also functionally active at the neurovascular interface. CYP expression is modulated by disease states, impacting cellular functions, detoxification, and reactivity to toxic stimuli and brain drug biotransformation. Unveiling the physiological and molecular complexity of brain P450 enzymes will improve our understanding of the mechanisms underlying brain drug availability, pharmacological efficacy, and neurotoxic adverse effects from pharmacotherapy targeting brain disorders.
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Affiliation(s)
- Chaitali Ghosh
- Cerebrovascular Research, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA; Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA; Department of Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA.
| | - Mohammed Hossain
- Cerebrovascular Research, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA; Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
| | | | - Aaron Dadas
- The Ohio State University, Columbus, OH, USA
| | - Nicola Marchi
- Cerebrovascular Mechanisms of Brain Disorders, Department of Neuroscience, Institute of Functional Genomics (CNRS/INSERM), Montpellier, France
| | - Damir Janigro
- Flocel Inc. and Case Western Reserve University, Cleveland, OH, USA
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Daci A, Beretta G, Vllasaliu D, Shala A, Govori V, Norata GD, Krasniqi S. Polymorphic Variants of SCN1A and EPHX1 Influence Plasma Carbamazepine Concentration, Metabolism and Pharmacoresistance in a Population of Kosovar Albanian Epileptic Patients. PLoS One 2015; 10:e0142408. [PMID: 26555147 PMCID: PMC4640545 DOI: 10.1371/journal.pone.0142408] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 10/20/2015] [Indexed: 12/24/2022] Open
Abstract
Aim The present study aimed to evaluate the effects of gene variants in key genes influencing pharmacokinetic and pharmacodynamic of carbamazepine (CBZ) on the response in patients with epilepsy. Materials & Methods Five SNPs in two candidate genes influencing CBZ transport and metabolism, namely ABCB1 or EPHX1, and CBZ response SCN1A (sodium channel) were genotyped in 145 epileptic patients treated with CBZ as monotherapy and 100 age and sex matched healthy controls. Plasma concentrations of CBZ, carbamazepine-10,11-epoxide (CBZE) and carbamazepine-10,11-trans dihydrodiol (CBZD) were determined by HPLC-UV-DAD and adjusted for CBZ dosage/kg of body weight. Results The presence of the SCN1A IVS5-91G>A variant allele is associated with increased epilepsy susceptibility. Furthermore, carriers of the SCN1A IVS5-91G>A variant or of EPHX1 c.337T>C variant presented significantly lower levels of plasma CBZ compared to carriers of the common alleles (0.71±0.28 vs 1.11±0.69 μg/mL per mg/Kg for SCN1A IVS5-91 AA vs GG and 0.76±0.16 vs 0.94±0.49 μg/mL per mg/Kg for EPHX1 c.337 CC vs TT; P<0.05 for both). Carriers of the EPHX1 c.416A>G showed a reduced microsomal epoxide hydrolase activity as reflected by a significantly decreased ratio of CBZD to CBZ (0.13±0.08 to 0.26±0.17, p<0.05) also of CBZD to CBZE (1.74±1.06 to 3.08±2.90; P<0.05) and CDRCBZD (0.13±0.08 vs 0.24±0.19 μg/mL per mg/Kg; P<0.05). ABCB1 3455C>T SNP and SCN1A 3148A>G variants were not associated with significant changes in CBZ pharmacokinetic. Patients resistant to CBZ treatment showed increased dosage of CBZ (657±285 vs 489±231 mg/day; P<0.001) but also increased plasma levels of CBZ (9.84±4.37 vs 7.41±3.43 μg/mL; P<0.001) compared to patients responsive to CBZ treatment. CBZ resistance was not related to any of the SNPs investigated. Conclusions The SCN1A IVS5-91G>A SNP is associated with susceptibility to epilepsy. SNPs in EPHX1 gene are influencing CBZ metabolism and disposition. CBZ plasma levels are not an indicator of resistance to the therapy.
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Affiliation(s)
- Armond Daci
- Department of Pharmacy, Faculty of Medicine, University of Prishtina, Prishtina, Kosovo
- Institute of Pharmacology and Toxicology and Clinical Pharmacology, Faculty of Medicine, University of Prishtina, Prishtina, Kosovo
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
| | - Giangiacomo Beretta
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milan, Italy
| | - Driton Vllasaliu
- University of Lincoln, School of Pharmacy, Joseph Banks Laboratories, Green Lane, Lincoln, LN6 7DL, United Kingdom
| | - Aida Shala
- Department of Pharmacy, Faculty of Medicine, University of Prishtina, Prishtina, Kosovo
| | - Valbona Govori
- Neurology Clinic, University Clinical Center of Kosova, Prishtina, Kosovo
| | - Giuseppe Danilo Norata
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
- Center for the Study of Atherosclerosis, Ospedale Bassini, Cinisello Balsamo, Italy
| | - Shaip Krasniqi
- Institute of Pharmacology and Toxicology and Clinical Pharmacology, Faculty of Medicine, University of Prishtina, Prishtina, Kosovo
- * E-mail:
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Saghazadeh A, Mahmoudi M, Meysamie A, Gharedaghi M, Zamponi GW, Rezaei N. Possible role of trace elements in epilepsy and febrile seizures: a meta-analysis. Nutr Rev 2015; 73:760-79. [DOI: 10.1093/nutrit/nuv026] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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Sandow N, Kim S, Raue C, Päsler D, Klaft ZJ, Antonio LL, Hollnagel JO, Kovacs R, Kann O, Horn P, Vajkoczy P, Holtkamp M, Meencke HJ, Cavalheiro EA, Pragst F, Gabriel S, Lehmann TN, Heinemann U. Drug resistance in cortical and hippocampal slices from resected tissue of epilepsy patients: no significant impact of p-glycoprotein and multidrug resistance-associated proteins. Front Neurol 2015; 6:30. [PMID: 25741317 PMCID: PMC4332373 DOI: 10.3389/fneur.2015.00030] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/03/2015] [Indexed: 01/16/2023] Open
Abstract
Drug resistant patients undergoing epilepsy surgery have a good chance to become sensitive to anticonvulsant medication, suggesting that the resected brain tissue is responsible for drug resistance. Here, we address the question whether P-glycoprotein (Pgp) and multidrug resistance-associated proteins (MRPs) expressed in the resected tissue contribute to drug resistance in vitro. Effects of anti-epileptic drugs [carbamazepine (CBZ), sodium valproate, phenytoin] and two unspecific inhibitors of Pgp and MRPs [verapamil (VPM) and probenecid (PBN)] on seizure-like events (SLEs) induced in slices from 35 hippocampal and 35 temporal cortex specimens of altogether 51 patients (161 slices) were studied. Although in slice preparations the blood brain barrier is not functional, we found that SLEs predominantly persisted in the presence of anticonvulsant drugs (90%) and also in the presence of VPM and PBN (86%). Following subsequent co-administration of anti-epileptic drugs and drug transport inhibitors, SLEs continued in 63% of 143 slices. Drug sensitivity in slices was recognized either as transition to recurrent epileptiform transients (30%) or as suppression (7%), particularly by perfusion with CBZ in PBN containing solutions (43, 9%). Summarizing responses to co-administration from more than one slice per patient revealed that suppression of seizure-like activity in all slices was only observed in 7% of patients. Patients whose tissue was completely or partially sensitive (65%) presented with higher seizure frequencies than those with resistant tissue (35%). However, corresponding subgroups of patients do not differ with respect to expression rates of drug transporters. Our results imply that parenchymal MRPs and Pgp are not responsible for drug resistance in resected tissue.
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Affiliation(s)
- Nora Sandow
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany ; Department of Neurosurgery, Charité Universitätsmedizin Berlin , Berlin , Germany
| | - Simon Kim
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany
| | - Claudia Raue
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany
| | - Dennis Päsler
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany
| | - Zin-Juan Klaft
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany
| | - Leandro Leite Antonio
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany ; Laboratorio de Neurologia Experimental, Universidade Federal de São Paulo-Escola Paulista de Medicina , São Paulo , Brazil
| | - Jan Oliver Hollnagel
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany
| | - Richard Kovacs
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany
| | - Oliver Kann
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany ; Institute of Physiology and Pathophysiology, University of Heidelberg , Heidelberg , Germany
| | - Peter Horn
- Department of Neurosurgery, Charité Universitätsmedizin Berlin , Berlin , Germany
| | - Peter Vajkoczy
- Department of Neurosurgery, Charité Universitätsmedizin Berlin , Berlin , Germany
| | - Martin Holtkamp
- Epilepsy Center of Berlin-Brandenburg, Ev. Krankenhaus Königin Elisabeth Herzberge , Berlin , Germany
| | - Heinz-Joachim Meencke
- Epilepsy Center of Berlin-Brandenburg, Ev. Krankenhaus Königin Elisabeth Herzberge , Berlin , Germany
| | - Esper A Cavalheiro
- Laboratorio de Neurologia Experimental, Universidade Federal de São Paulo-Escola Paulista de Medicina , São Paulo , Brazil
| | - Fritz Pragst
- Institute of Forensic Medicine - Forensic Toxicology, Charité Universitätsmedizin Berlin , Berlin , Germany
| | - Siegrun Gabriel
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany
| | | | - Uwe Heinemann
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin , Berlin , Germany
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Gullo F, Manfredi I, Lecchi M, Casari G, Wanke E, Becchetti A. Multi-electrode array study of neuronal cultures expressing nicotinic β2-V287L subunits, linked to autosomal dominant nocturnal frontal lobe epilepsy. An in vitro model of spontaneous epilepsy. Front Neural Circuits 2014; 8:87. [PMID: 25104926 PMCID: PMC4109561 DOI: 10.3389/fncir.2014.00087] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 07/04/2014] [Indexed: 11/13/2022] Open
Abstract
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is a partial sleep-related epilepsy which can be caused by mutant neuronal nicotinic acetylcholine receptors (nAChR). We applied multi-electrode array (MEA) recording methods to study the spontaneous firing activity of neocortical cultures obtained from mice expressing or not (WT) an ADNFLE-linked nAChR subunit (β2-V287L). More than 100,000 up-states were recorded during experiments sampling from several thousand neurons. Data were analyzed by using a fast sliding-window procedure which computes histograms of the up-state durations. Differently from the WT, cultures expressing β2-V287L displayed long (10–32 s) synaptic-induced up-state firing events. The occurrence of such long up-states was prevented by both negative (gabazine, penicillin G) and positive (benzodiazepines) modulators of GABAA receptors. Carbamazepine (CBZ), a drug of choice in ADNFLE patients, also inhibited the long up-states at micromolar concentrations. In cultures expressing β2-V287L, no significant effect was observed on the action potential waveform either in the absence or in the presence of pharmacological treatment. Our results show that some aspects of the spontaneous hyperexcitability displayed by a murine model of a human channelopathy can be reproduced in neuronal cultures. In particular, our cultures represent an in vitro chronic model of spontaneous epileptiform activity, i.e., not requiring pre-treatment with convulsants. This opens the way to the study in vitro of the role of β2-V287L on synaptic formation. Moreover, our neocortical cultures on MEA platforms allow to determine the effects of prolonged pharmacological treatment on spontaneous network hyperexcitability (which is impossible in the short-living brain slices). Methods such as the one we illustrate in the present paper should also considerably facilitate the preliminary screening of antiepileptic drugs (AEDs), thereby reducing the number of in vivo experiments.
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Affiliation(s)
- Francesca Gullo
- Department of Biotechnology and Biosciences, University of Milano-Bicocca Milano, Italy
| | - Irene Manfredi
- Center for Translational Genomics and Bioinformatics, Vita-Salute San Raffaele University and San Raffaele Scientific Institute Milano, Italy
| | - Marzia Lecchi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca Milano, Italy
| | - Giorgio Casari
- Center for Translational Genomics and Bioinformatics, Vita-Salute San Raffaele University and San Raffaele Scientific Institute Milano, Italy
| | - Enzo Wanke
- Department of Biotechnology and Biosciences, University of Milano-Bicocca Milano, Italy
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca Milano, Italy
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Janigro D. Are you in or out? Leukocyte, ion, and neurotransmitter permeability across the epileptic blood-brain barrier. Epilepsia 2012; 53 Suppl 1:26-34. [PMID: 22612806 PMCID: PMC4093790 DOI: 10.1111/j.1528-1167.2012.03472.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The credo that epileptic seizures can be initiated only by "epileptic" neurons has been recently challenged. The recognition of key astrocytic-neuronal communication, and the close interaction and crosstalk between astrocytes and brain endothelial cells, has shifted attention to the blood-brain barrier (BBB) and the "neurovascular unit." Therefore, the pursuit of mechanisms of seizure generation and epileptogenesis now includes investigations of cerebral blood flow and permeability of cerebral microvessels. For example, leukocyte adhesion molecules at the BBB have been proposed to play a role as an initiating factor for pilocarpine-induced status epilepticus, and a viral infection model with a strong BBB etiology has been used to study epileptogenesis. Finally, the fact that in nonepileptic subjects seizures can be triggered by BBB disruption, together with the antiseizure effects obtained by administration of potent antiinflammatory "BBB repair" drugs, has increased the interest in neuroinflammation; both circulating leukocytes and resident microglia have been studied in this context. The dual scope of this review is the following: (1) outline the proposed role of BBB damage and immune cell activation in seizure disorders; and (2) explain how increased cerebrovascular permeability causes neuronal misfiring. The temporal sequence linking seizures to peripheral inflammation and BBB dysfunction remains to be clarified. For example, it is still debated whether seizures cause systemic inflammation or vice versa. The topographic localization of fundamental triggers of epileptic seizures also remains controversial: Are immunologic mechanisms required for seizure generation brain-specific or is systemic activation of immunity sufficient to alter neuronal excitability? Finally, the causative role of "BBB leakage" remains a largely unresolved issue.
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Affiliation(s)
- Damir Janigro
- Departments of Neurological Surgery, Molecular Medicine and Cell Biology, ClevelandClinic Foundation, Euclid Avenue, Cleveland, OH 44195, U.S.A.
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Wahab A. Difficulties in Treatment and Management of Epilepsy and Challenges in New Drug Development. Pharmaceuticals (Basel) 2010; 3:2090-2110. [PMID: 27713344 PMCID: PMC4036655 DOI: 10.3390/ph3072090] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 06/28/2010] [Accepted: 07/02/2010] [Indexed: 02/07/2023] Open
Abstract
Epilepsy is a serious neurological disorder that affects around 50 million people worldwide. Almost 30% of epileptic patients suffer from pharmacoresistance, which is associated with social isolation, dependent behaviour, low marriage rates, unemployment, psychological issues and reduced quality of life. Currently available antiepileptic drugs have a limited efficacy, and their negative properties limit their use and cause difficulties in patient management. Antiepileptic drugs can provide only symptomatic relief as these drugs suppress seizures but do not have ability to cure epileptogenesis. The long term use of antiepileptic drugs is limited due to their adverse effects, withdrawal symptoms, deleterious interactions with other drugs and economic burden, especially in developing countries. Furthermore, some of the available antiepileptic drugs may even potentiate certain type of seizures. Several in vivo and in vitro animal models have been proposed and many new antiepileptic drugs have been marketed recently, but large numbers of patients are still pharmacoresistant. This review will highlight the difficulties in treatment and management of epilepsy and the limitations of available antiepileptic drugs and animal seizure models.
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Affiliation(s)
- Abdul Wahab
- Institute of Neurophysiology, Charité Berlin Medical University, Tucholskystrasse 2, D-10117 Berlin, Germany.
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Granata T, Marchi N, Carlton E, Ghosh C, Gonzalez-Martinez J, Alexopoulos AV, Janigro D. Management of the patient with medically refractory epilepsy. Expert Rev Neurother 2009; 9:1791-802. [PMID: 19951138 PMCID: PMC3761964 DOI: 10.1586/ern.09.114] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Epilepsy imposes a significant clinical, epidemiologic and economic burden on societies throughout the world. Despite the development of more than ten new antiepileptic drugs over the past 15 years, approximately a third of patients with epilepsy remain resistant to pharmacotherapy. Individuals who fail to respond, or respond only partially, continue to have incapacitating seizures. Managing patients with medically refractory epilepsy is challenging and requires a structured multidisciplinary approach in specialized clinics. If the problems related to drug resistance could be resolved, even in part, by improving the pharmacokinetic profile of existing drugs, the economic savings would be remarkable and the time required to design drugs that achieve seizure control would be shorter than the discovery of new targets and molecules was required. A promising approach is the use of corticosteroids that may have a dual beneficial effect. Resective brain surgery remains the ultimate and highly successful approach to multiple drug resistance in epileptic patients.
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Affiliation(s)
- Tiziana Granata
- Department of Neurology, Cleveland, OH, USA, Department of Child Neurology, Carlo Besta Neurological Institute, Milan, Italy, Tel.: +39 022 394 302, Fax: +39 027 063 8217
| | - Nicola Marchi
- Department of Cell Biology and Cerebrovascular Research Cleveland Clinic Foundation, Cleveland, OH, USA, Tel.: +1 216 445 0561, Fax: +1 216 445 1466
| | - Erin Carlton
- Cerebrovascular Research Cleveland Clinic Foundation, Cleveland, OH, USA, Tel.: +1 216 445 0561, Fax: +1 216 445 1466
| | - Chaitali Ghosh
- Department of Cell Biology and Cerebrovascular Research Cleveland Clinic Foundation, Cleveland, OH, USA, Tel.: +1 216 445 0561, Fax: +1 216 445 1466
| | - Jorge Gonzalez-Martinez
- Department of Neurological Surgery, Cleveland, OH, USA, Tel.: +1 216 445 0561, Fax: +1 216 445 1466
| | - Andreas V Alexopoulos
- Cleveland Clinic Epilepsy Center, 9500 Euclid Ave, S-51, Cleveland, OH 44195, USA, Tel.: +1 216 444 3629, Fax: +1 216 445 4378
| | - Damir Janigro
- Departments of Neurological Surgery, Molecular Medicine and Cell Biology and the Cerebrovascular Research Cleveland Clinic Foundation, Cleveland, OH, USA, Tel.: +1 216 445 0561, Fax: +1 216 445 1466
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Wahab A, Heinemann U, Albus K. Effects of γ-aminobutyric acid (GABA) agonists and a GABA uptake inhibitor on pharmacoresistant seizure like events in organotypic hippocampal slice cultures. Epilepsy Res 2009; 86:113-23. [DOI: 10.1016/j.eplepsyres.2009.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 05/09/2009] [Accepted: 05/11/2009] [Indexed: 10/20/2022]
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Marchi N, Betto G, Fazio V, Fan Q, Ghosh C, Machado A, Janigro D. Blood-brain barrier damage and brain penetration of antiepileptic drugs: role of serum proteins and brain edema. Epilepsia 2009; 50:664-77. [PMID: 19175391 PMCID: PMC2824251 DOI: 10.1111/j.1528-1167.2008.01989.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Increased blood-brain barrier (BBB) permeability is radiologically detectable in regions affected by drug-resistant epileptogenic lesions. Brain penetration of antiepileptic drugs (AEDs) may be affected by BBB damage. We studied the effects of BBB damage on brain distribution of hydrophilic [deoxy-glucose (DOG) and sucrose] and lipophilic (phenytoin and diazepam) molecules. We tested the hypothesis that lipophilic and hydrophilic drug distribution is differentially affected by BBB damage. METHODS In vivo BBB disruption (BBBD) was performed in rats by intracarotid injection of hyperosmotic mannitol. Drugs (H3-sucrose, 3H-deoxy-glucose, 14C-phenytoin, and C14-diazepam) or unlabeled phenytoin was measured and correlated to brain water content and protein extravasation. In vitro hippocampal slices were exposed to different osmolarities; drug penetration and water content were assessed by analytic and densitometric methods, respectively. RESULTS BBBD resulted in extravasation of serum protein and radiolabeled drugs, but was associated with no significant change in brain water. Large shifts in water content in brain slices in vitro caused a small effect on drug penetration. In both cases, total drug permeability increase was greater for lipophilic than hydrophilic compounds. BBBD reduced the amount of free phenytoin in the brain. DISCUSSION After BBBD, drug binding to protein is the main controller of total brain drug accumulation. Osmotic BBBD increased serum protein extravasation and reduced free phenytoin brain levels. These results underlie the importance of brain environment and BBB integrity in determining drug distribution to the brain. If confirmed in drug-resistant models, these mechanisms could contribute to drug brain distribution in refractory epilepsies.
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Affiliation(s)
- Nicola Marchi
- Department of Neurological Surgery, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cell Biology, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cerebrovascular Research, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
| | - Giulia Betto
- Department of Neurological Surgery, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cell Biology, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cerebrovascular Research, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
| | - Vincent Fazio
- Department of Neurological Surgery, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cell Biology, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cerebrovascular Research, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
| | - Quinyuan Fan
- Department of Neurological Surgery, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cell Biology, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cerebrovascular Research, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
| | - Chaitali Ghosh
- Department of Neurological Surgery, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cell Biology, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cerebrovascular Research, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
| | - Andre Machado
- Center for Restorative Neuroscience, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
| | - Damir Janigro
- Department of Neurological Surgery, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cell Biology, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Cerebrovascular Research, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
- Department of Molecular Medicine, Cleveland Clinic Foundation, Cleveland, Ohio, U.S.A
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Tan L, Yu JT, Guan HS. Intranasal anticonvulsive treatment: A prospective management of intractable epilepsy? Med Hypotheses 2008; 71:542-5. [DOI: 10.1016/j.mehy.2008.05.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2008] [Revised: 05/18/2008] [Accepted: 05/20/2008] [Indexed: 11/25/2022]
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Hughes JR. One of the hottest topics in epileptology: ABC proteins. Their inhibition may be the future for patients with intractable seizures. Neurol Res 2008; 30:920-5. [PMID: 18593522 DOI: 10.1179/174313208x319116] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
One of the new topics in epileptology is the ABC proteins, which seem to control whether or not anti-epileptic drugs (AEDs) can come in contact with and affect the epileptogenic areas that cause seizures. The goal of this report is to simplify the concepts involved in these proteins and then to review the progress made in the field, especially of one protein called P-glycoprotein (P-gp). First, the ABC proteins are reviewed, mainly P-gp, which appears to alter drug permeability (like an extra blood-brain barrier). The possibility is discussed that changes in P-gp are the result of many seizures; are caused by the AEDs, or truly reflect pharmacoresistance. The different locations where these changes can be seen include the endothelial cells, glia and also neurons. The polymorphism of P-gp, called C3435T, probably has little functional significance and finally the importance of inhibitors of P-g to reverse pharmacoresistance is emphasized. Tariquidar (XR9576) is likely to be a good candidate that appears to inhibit these proteins and therefore to allow the AEDs to control the intractable seizures that may account for nearly 40% of our patients.
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Affiliation(s)
- John R Hughes
- Department of Neurology, University of Illinois Medical Center, 912 S. Wood Street, Chicago, IL 60612, USA.
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Standard antiepileptic drugs fail to block epileptiform activity in rat organotypic hippocampal slice cultures. Br J Pharmacol 2008; 154:709-24. [PMID: 18414393 DOI: 10.1038/bjp.2008.112] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND AND PURPOSE Earlier studies had demonstrated that tonic-clonic seizure-like events (SLEs) resembling electrographic correlates of limbic seizures in animals and humans can be induced in organotypic hippocampal slice cultures (OHSCs). We have explored OHSCs for their suitability to serve as in vitro models of limbic seizures for studying seizure mechanisms and screening new antiepileptic compounds. EXPERIMENTAL APPROACH OHSCs were cultivated according to the interface method. Neuronal activity and extracellular potassium concentration were recorded under submerged conditions. SLEs were induced by lowering magnesium concentration or by applying the potassium channel blocker 4-aminopyridine. The effects of standard antiepileptic drugs (AEDs), carbamazepine, phenytoin, valproic acid, clonazepam, diazepam and phenobarbital sodium on SLEs were analysed. KEY RESULTS In more than 93% of OHSCs, AEDs did not prevent the induction of SLEs or stop ongoing seizure activity even when toxic concentrations were applied. This pharmacoresistance was independent of the method of seizure provocation, postnatal age at explantation (P2-P10) and cultivation time in vitro (2 months). SLEs were reversibly blocked by glutamate antagonists or the GABA(A)-agonist muscimol. CONCLUSIONS AND IMPLICATIONS We present a simple to establish in vitro model of tonic-clonic SLEs that is a priori pharmacoresistant and thus has an advantage over animal models of pharmacoresistant seizures in which responders and non-responders can be sorted out only after an experiment. OHSCs could be suitable for exploring mechanisms of pharmacoresistant seizures and be used for the identification of new anticonvulsive compounds eventually effective in drug refractory epilepsy.
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Cucullo L, Hossain M, Rapp E, Manders T, Marchi N, Janigro D. Development of a Humanized In Vitro Blood?Brain Barrier Model to Screen for Brain Penetration of Antiepileptic Drugs. Epilepsia 2007; 48:505-16. [PMID: 17326793 DOI: 10.1111/j.1528-1167.2006.00960.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE A biotechnologic breakthrough for the study of drug permeability across the blood-brain barrier (BBB) would be the use of a reproducible in vitro model that recapitulates the functional, structural, and pathologic properties of the BBB in situ. We developed a humanized dynamic in vitro BBB model (DIV-BBB) based on cocultures of human microvascular endothelial cells (HBMECs) from "normal" and drug-resistant epileptic brain tissue with human brain astrocytes (HAs) from epilepsy patients or controls. METHODS HBMECs and HAs were cocultured for 28 days in polypropylene capillaries. HBMECs were exposed to physiologic levels of shear stress generated by intraluminal flow. Permeability to [3H]sucrose, [14C]phenytoin, and [14C]diazepam was measured in control and drug-resistant DIV-BBB with and without pretreatment with the MDR1 inhibitor XR9576. BBB integrity was monitored by transendothelial electrical resistance measurements (TEERs). Cell growth and viability were assessed by measurement of glucose consumption and lactate production. RESULTS PSucrose and TEER values did not depend on the origin of the endothelium used (epileptic or normal). PPhenytoin was 10-fold less (1.54 x 10(-6) cm/s) in drug-resistant BBB models than in controls (1.74 x 10(-5) cm/s). MDR1 blockade with XR9576 was effective (3.5-fold increase) only in drug-resistant cultures. PDiazepam in control and drug-resistant DIV-BBB was not affected by XR9576 and did not depend on the epileptic or control origin of endothelia. The overall contribution of epileptic glia to pharmacoresistance was negligible. CONCLUSIONS These results show that, for the substances used, the humanized DIV-BBB recapitulates the physiologic permeability properties of the BBB in vivo and is also capable of mimicking a drug-resistant BBB phenotype.
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Affiliation(s)
- Luca Cucullo
- Center for Cerebrovascular Research, Cleveland, Ohio, USA
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Abstract
The amount of new knowledge being generated regarding brain mechanisms in general, and epileptic mechanisms in particular, is enormous. Anticonvulsant drugs are ineffective in approximately a third of people with epilepsy. To our knowledge, strategies for preventing epilepsy after an initial insult are nonexistent. In this review, we briefly examine some recent novel concepts for preventing seizures, which might lead to enhanced anticonvulsant drug therapy. We start with some known seizure mechanisms that have yet to yield widely used anticonvulsant drugs, including potassium channels, chloride cotransporters, extracellular space constriction, gap junctions and magnesium. Pharmacoresistance is then discussed, focusing on the upregulation of drug-resistance proteins (a concept with significant therapeutic appeal) and the drug-target hypothesis. Two further areas that hold great promise for future therapeutics are sex hormones and inflammatory processes. The genetics of epilepsy are currently being elaborated, providing potential novel anticonvulsant targets. Prevention being better than a cure, we discuss epileptogenesis and its treatment. Given the astounding progress of neuroscience research, one hopes for many new therapeutics for our intractable epileptic patients.
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Affiliation(s)
- Danielle M Andrade
- University of Toronto, Division of Neurology, Epilepsy Program, Krembil neuroscience Centre, Toronto Western Hospital, Deparment of Medicine, 5W-445, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8
| | - Peter L Carlen
- University of Toronto, Division of Neurology, Epilepsy Program, Krembil neuroscience Centre, Toronto Western Hospital & Toronto Western Research Institute, Departments of Medicine, Physiology & IBBME, 5W-442, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8
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Abstract
During the past several years, there has been increasing interest in the role of the blood-brain barrier (BBB) in epilepsy. Advances in neuroradiology have enhanced our ability to image and study the human cerebrovasculature, and further developments in the research of metabolic deficiencies linked to seizure disorders (e.g., GLUT1 deficiency), neuroinflammation, and multiple drug resistance to antiepileptic drugs (AEDs) have amplified the significance of the BBB's relationship to epilepsy. Prior to 1986, BBB research in epilepsy focused on three main areas: ultrastructural studies, brain glucose availability and transport, and clinical uses of AEDs. However, contrast-based imaging techniques and medical procedures such as BBB disruption provided a framework that demonstrated that the BBB could be reversibly disrupted by pathologic or iatrogenic manipulations, with important implications in terms of CNS drug delivery to "multiple drug resistant" brain. This concept of BBB breakdown for therapeutic purposes has also unveiled a previously unrecognized role for BBB failure as a possible etiologic mechanism in epileptogenesis. Finally, a growing body of evidence has shown that inflammatory mechanisms may participate in the pathological changes observed in epileptic brain, with increasing awareness that blood-borne cells or signals may participate in epileptogenesis by virtue of a leaky BBB. In this article we will review the relationships between BBB function and epilepsy. In particular, we will illustrate consensus and divergence between clinical reality and animal studies.
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Affiliation(s)
- Emily Oby
- Cleveland Clinic Foundation, Department of Neurological Surgery, Cerebrovascular Research, Ohio 44195, USA
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