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Campos-Bedolla P, Feria-Romero I, Orozco-Suárez S. Factors not considered in the study of drug-resistant epilepsy: Drug-resistant epilepsy: assessment of neuroinflammation. Epilepsia Open 2022; 7 Suppl 1:S68-S80. [PMID: 35247028 PMCID: PMC9340302 DOI: 10.1002/epi4.12590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 02/15/2022] [Accepted: 02/27/2022] [Indexed: 11/13/2022] Open
Abstract
More than one‐third of people with epilepsy develop drug‐resistant epilepsy (DRE). Different hypotheses have been proposed to explain the origin of DRE. Accumulating evidence suggests the contribution of neuroinflammation, modifications in the integrity of the blood‐brain barrier (BBB), and altered immune responses in the pathophysiology of DRE. The inflammatory response is mainly due to the increase of cytokines and related molecules; these molecules have neuromodulatory effects that contribute to hyperexcitability in neural networks that cause seizure generation. Some patients with DRE display the presence of autoantibodies in the serum and mainly cerebrospinal fluid. These patients are refractory to the different treatments with standard antiseizure medications (ASMs), and they could be responding well to immunomodulatory therapies. This observation emphasizes that the etiopathogenesis of DRE is involved with immunology responses and associated long‐term events and chronic inflammation processes. Furthermore, multiple studies have shown that functional polymorphisms as risk factors are involved in inflammation processes. Several relevant polymorphisms could be considered risk factors involved in inflammation‐related DRE such as receptor for advanced glycation end products (RAGE) and interleukin 1β (IL‐1β). All these evidences sustained the hypothesis that the chronic inflammation process is associated with the DRE. However, the effect of the chronic inflammation process should be investigated in further clinical studies to promote the development of novel therapeutics useful in treatment of DRE.
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Affiliation(s)
- Patricia Campos-Bedolla
- Unidad de Investigación Médica en Enfermedades Neurológicas, Hospital de Especialidades, "Dr. Bernardo Sepúlveda", Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México
| | - Iris Feria-Romero
- Unidad de Investigación Médica en Enfermedades Neurológicas, Hospital de Especialidades, "Dr. Bernardo Sepúlveda", Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México
| | - Sandra Orozco-Suárez
- Unidad de Investigación Médica en Enfermedades Neurológicas, Hospital de Especialidades, "Dr. Bernardo Sepúlveda", Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, México
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2
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Fonseca-Barriendos D, Pérez-Pérez D, Fuentes-Mejía M, Orozco-Suárez S, Alonso-Vanegas M, Martínez-Juárez IE, Guevara-Guzmán R, Castañeda-Cabral JL, Rocha L. Protein expression of P-glycoprotein in neocortex from patients with frontal lobe epilepsy. Epilepsy Res 2022; 181:106892. [DOI: 10.1016/j.eplepsyres.2022.106892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 02/11/2022] [Accepted: 02/18/2022] [Indexed: 01/16/2023]
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3
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Bernier LP, Brunner C, Cottarelli A, Balbi M. Location Matters: Navigating Regional Heterogeneity of the Neurovascular Unit. Front Cell Neurosci 2021; 15:696540. [PMID: 34276312 PMCID: PMC8277940 DOI: 10.3389/fncel.2021.696540] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 05/31/2021] [Indexed: 12/27/2022] Open
Abstract
The neurovascular unit (NVU) of the brain is composed of multiple cell types that act synergistically to modify blood flow to locally match the energy demand of neural activity, as well as to maintain the integrity of the blood-brain barrier (BBB). It is becoming increasingly recognized that the functional specialization, as well as the cellular composition of the NVU varies spatially. This heterogeneity is encountered as variations in vascular and perivascular cells along the arteriole-capillary-venule axis, as well as through differences in NVU composition throughout anatomical regions of the brain. Given the wide variations in metabolic demands between brain regions, especially those of gray vs. white matter, the spatial heterogeneity of the NVU is critical to brain function. Here we review recent evidence demonstrating regional specialization of the NVU between brain regions, by focusing on the heterogeneity of its individual cellular components and briefly discussing novel approaches to investigate NVU diversity.
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Affiliation(s)
- Louis-Philippe Bernier
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Clément Brunner
- Neuro-Electronics Research Flanders, Leuven, Belgium.,Vlaams Instituut voor Biotechnologie, Leuven, Belgium.,Interuniversity Microeletronics Centre, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | | | - Matilde Balbi
- Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
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4
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Ethemoğlu ÖU, Kayrak N, Bılgıç B, Gül G, Kuşçu DY, Kirbaş D. The Relationship Between Clinico-Pathological Properties and p-Glycoprotein Expression in Hippocampal Sclerosis Among Patients with Mesial Temporal Lobe Epilepsy Who Undergo Selective Amygdalohippocampectomy Operation. Noro Psikiyatr Ars 2020; 57:204-209. [PMID: 32952422 PMCID: PMC7481975 DOI: 10.29399/npa.23363] [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: 09/03/2018] [Accepted: 10/12/2018] [Indexed: 11/07/2022] Open
Abstract
INTRODUCTION The overproduction of the efflux transporters in the blood-brain barrier is considered to play a role in the development of drug resistance in mesial temporal lobe epilepsy (MTLE) patients. The aim of the present study was to investigate the relationship of clinical features of patients with MTLE accompanied by hippocampal sclerosis (HS) and the p-glycoprotein (p-gp) expression and neuronal loss in the hippocampus. METHODS This study included a total of 33 patients who underwent selective amygdala-hippocampectomy operation. A detailed medical history of each patient, including age, side of HS, sex, age of habitual seizure onset, duration of habitual seizures, type and age of initial precipitating injury, presence and duration of latent period, presence and duration of silent period, monthly seizure frequency within 1 year prior to operation, mean age at the time of operation was evaluated retrospectively. RESULTS The p-gp expression was significantly higher in the patient group with a seizure frequency of more than 15 days per month and a disease duration of more than 20 years. There was no significant difference between the p-gp expression and the clinical features of the MTLE-HS patients. CONCLUSION These results suggest that p-gp expression is affected by disease duration and seizure frequency rather than a patient's clinical and pathological properties. In patients with HS-MTLE, potential use of the p-gp inhibitors as additional therapy and developing novel drugs not carried by multidrug carriers expressed in blood-brain barrier should be regarded as the new treatment targets.
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Affiliation(s)
| | - Nalan Kayrak
- Private Practice, Neurology, Assoc. Prof., İstanbul, Turkey
| | - Bilge Bılgıç
- Department of Pathology, İstanbul Faculty of Medicine, İstanbul University, İstanbul, Turkey
| | - Günay Gül
- Neurology and Neurosurgery Department, Bakırköy Prof. Dr. Mazhar Osman Training and Research Hospital for Psychiatry, İstanbul, Turkey
| | | | - Dursun Kirbaş
- Department of Neurology, Gaziosmanpaşa Hospital, İstanbul, Turkey
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5
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Janmohamed M, Brodie MJ, Kwan P. Pharmacoresistance - Epidemiology, mechanisms, and impact on epilepsy treatment. Neuropharmacology 2019; 168:107790. [PMID: 31560910 DOI: 10.1016/j.neuropharm.2019.107790] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/01/2019] [Accepted: 09/21/2019] [Indexed: 12/25/2022]
Abstract
Understanding the natural history of and factors associated with pharmacoresistant epilepsy provides the foundation for formulating mechanistic hypotheses that can be evaluated to drive the development of novel treatments. This article reviews the modern definition of drug-resistant epilepsy, its prevalence and incidence, risk factors, hypothesized mechanisms, and the implication of recognizing pharmacoresistance in therapeutic strategies. 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)
- Mubeen Janmohamed
- Department of Neuroscience, Alfred Hospital, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | | | - Patrick Kwan
- Department of Neuroscience, Alfred Hospital, Central Clinical School, Monash University, Melbourne, Victoria, Australia; Departments of Medicine and Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia.
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6
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Fei Z, Hu M, Baum L, Kwan P, Hong T, Zhang C. The potential role of human multidrug resistance protein 1 (MDR1) and multidrug resistance-associated protein 2 (MRP2) in the transport of Huperzine A in vitro. Xenobiotica 2019; 50:354-362. [PMID: 31132291 DOI: 10.1080/00498254.2019.1623935] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Ziyan Fei
- School of Pharmacy, Nanchang University, Nanchang, PR China
- Provincial Key Laboratory for Drug Targeting and Drug Screening Research, Nanchang, PR China
| | - Mengyun Hu
- School of Pharmacy, Nanchang University, Nanchang, PR China
- Provincial Key Laboratory for Drug Targeting and Drug Screening Research, Nanchang, PR China
| | - Larry Baum
- The State Key Laboratory of Brain and Cognitive Sciences, University of Hong Kong, Pokfulam, Hong Kong, PR China
- Centre for Genomic Sciences, University of Hong Kong, Pokfulam, Hong Kong, PR China
| | - Patrick Kwan
- Department of Neuroscience, Alfred Hospital, Monash University, Melbourne, Australia
- Departments of Medicine and Neurology, Royal Melbourne Hospital, The University of Melbourne, Melbourne, Australia
| | - Tao Hong
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, PR China
| | - Chunbo Zhang
- School of Pharmacy, Nanchang University, Nanchang, PR China
- Provincial Key Laboratory for Drug Targeting and Drug Screening Research, Nanchang, PR China
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7
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Zhang C, Kwan P. The Concept of Drug-Resistant Epileptogenic Zone. Front Neurol 2019; 10:558. [PMID: 31214106 PMCID: PMC6555267 DOI: 10.3389/fneur.2019.00558] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/09/2019] [Indexed: 12/01/2022] Open
Abstract
Resective surgery is the most effective way to treat drug-resistant epilepsy. Despite extensive pre-surgical evaluation, only 30–70% patients would become seizure-free after surgery. New approaches and strategies are needed to improve the outcome of epilepsy surgery. It is commonly observed in clinical practice that antiepileptic drugs (AEDs) could maintain seizure freedom in a large proportion of patients after surgery, who were uncontrolled before the operation. In some patients cessation of AEDs leads to seizure recurrence which, in most cases, can be controlled by resuming AEDs. These observations suggest that the surgery has converted the epilepsy from drug-resistant to drug-responsive, implying that the operation has removed the brain tissue accounting for pharmacoresistance, rather than the pathological substrate of epilepsy (at least not completely). Based on these observations, it is hypothesized that there is a drug-resistant epileptogenic zone (DREZ) which overlaps with the epileptogenic zone (EZ), and has both epileptogenic and drug-resistant properties. DREZ is necessary and sufficient to cause drug-resistant epilepsy, and its remove would render the epilepsy drug-responsive. Testing the hypothesis requires the development of new methods to define the DREZ, which may be used to guide surgical planning when the epileptogenic zone cannot be completely excised. This concept can also help understand the mechanisms of drug-resistant epilepsy, leading to new therapeutic strategies.
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Affiliation(s)
- Chunbo Zhang
- School of Pharmacy, Nanchang University, Nanchang, China
| | - Patrick Kwan
- Department of Neuroscience, Alfred Hospital, Monash University, Melbourne, VIC, Australia.,Departments of Medicine and Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
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8
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ABC transporters in drug-resistant epilepsy: mechanisms of upregulation and therapeutic approaches. Pharmacol Res 2019; 144:357-376. [PMID: 31051235 DOI: 10.1016/j.phrs.2019.04.031] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/23/2019] [Accepted: 04/24/2019] [Indexed: 02/07/2023]
Abstract
Drug-resistant epilepsy (DRE) affects approximately one third of epileptic patients. Among various theories that try to explain multidrug resistance, the transporter hypothesis is the most extensively studied. Accordingly, the overexpression of efflux transporters in the blood-brain barrier (BBB), mainly from the ATP binding cassette (ABC) superfamily, may be responsible for hampering the access of antiepileptic drugs into the brain. P-glycoprotein and other efflux transporters are known to be upregulated in endothelial cells, astrocytes and neurons of the neurovascular unit, a functional barrier critically involved in the brain penetration of drugs. Inflammation and oxidative stress involved in the pathophysiology of epilepsy together with uncontrolled recurrent seizures, drug-associated induction and genetic polymorphisms are among the possible causes of ABC transporters overexpression in DRE. The aforementioned pathological mechanisms will be herein discussed together with the multiple strategies to overcome the activity of efflux transporters in the BBB - from direct transporters inhibition to down-regulation of gene expression resorting to RNA interference (RNAi), or by targeting key modulators of inflammation and seizure-mediated signalling.
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9
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Ferreira A, Rodrigues M, Meirinho S, Fortuna A, Falcão A, Alves G. Silymarin as a flavonoid-type P-glycoprotein inhibitor with impact on the pharmacokinetics of carbamazepine, oxcarbazepine and phenytoin in rats. Drug Chem Toxicol 2019; 44:458-469. [PMID: 31020859 DOI: 10.1080/01480545.2019.1601736] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
P-glycoprotein (P-gp) is an efflux transporter involved in drug-resistant epilepsy and some flavonoids have been targeted as effective P-gp inhibitors. Herein, we assessed the impact of silymarin on the pharmacokinetics of three antiepileptic drugs (AEDs) in rats. Animals were pretreated with silymarin, verapamil (positive control) or vehicle (negative control) 1 h before AEDs administration (carbamazepine (25 mg/kg), oxcarbazepine (OXC) (50 mg/kg), or phenytoin (100 mg/kg)). Multiple blood samples were collected after AED dosing, and a non-compartmental analysis was performed. An independent study was also conducted to investigate the effects of silymarin on the OXC plasma-to-brain distribution. Silymarin altered the pharmacokinetics of OXC, increasing its peak plasma concentration by 50% and its extent of systemic exposure by 41%, which had also impact on brain drug concentrations. These findings support that the co-administration of silymarin and OXC should continue to be explored as a strategy to reverse the pharmacoresistance in epilepsy.
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Affiliation(s)
- Ana Ferreira
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal.,CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Márcio Rodrigues
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal.,UDI-IPG - Research Unit for Inland Development, Polytechnic Institute of Guarda, Guarda, Portugal
| | - Sara Meirinho
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Ana Fortuna
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Laboratory of Pharmacology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, Coimbra, Portugal
| | - Amílcar Falcão
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Laboratory of Pharmacology, Faculty of Pharmacy, University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, Coimbra, Portugal
| | - Gilberto Alves
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal.,CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
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10
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Ferreira A, Rodrigues M, Fortuna A, Falcão A, Alves G. Flavonoid compounds as reversing agents of the P-glycoprotein-mediated multidrug resistance: An in vitro evaluation with focus on antiepileptic drugs. Food Res Int 2018; 103:110-120. [DOI: 10.1016/j.foodres.2017.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/29/2017] [Accepted: 10/07/2017] [Indexed: 01/16/2023]
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11
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Chi X, Huang C, Li R, Wang W, Wu M, Li J, Zhou D. Inhibition of mTOR Pathway by Rapamycin Decreases P-glycoprotein Expression and Spontaneous Seizures in Pharmacoresistant Epilepsy. J Mol Neurosci 2017; 61:553-562. [PMID: 28229367 DOI: 10.1007/s12031-017-0897-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 02/08/2017] [Indexed: 02/05/2023]
Abstract
The mammalian target of rapamycin (mTOR) has been demonstrated to mediate multidrug resistance in various tumors by inducing P-glycoprotein (P-gp) overexpression. Here, we investigated the correlation between the mTOR pathway and P-gp expression in pharmacoresistant epilepsy. Temporal cortex specimens were obtained from patients with refractory mesial temporal lobe epilepsy (mTLE) and age-matched controls who underwent surgeries at West China Hospital of Sichuan University between June 2014 and May 2015. We established a rat model of epilepsy kindled by coriaria lactone (CL) and screened pharmacoresistant rats (non-responders) using phenytoin. Non-responders were treated for 4 weeks with vehicle only or with the mTOR pathway inhibitor rapamycin at doses of 1, 3, and 6 mg/kg. Western blotting and immunohistochemistry were used to detect the expression of phospho-S6 (P-S6) and P-gp at different time points (1 h, 8 h, 1 day, 3 days, 1 weeks, 2 weeks, and 4 weeks) after the onset of treatment. Overexpression of P-S6 and P-gp was detected in both refractory mTLE patients and non-responder rats. Rapamycin showed an inhibitory effect on P-S6 and P-gp expression 1 week after treatment in rats. In addition, the expression levels of P-S6 and P-gp in the 6 mg/kg group were significantly lower than those in the 1 mg/kg or the 3 mg/kg group at the same time points (all P < 0.05). Moreover, rapamycin decreased the duration and number of CL-induced seizures, as well as the stage of non-responders (all P < 0.05). The current study indicates that the mTOR signaling pathway plays a critical role in P-gp expression in drug-resistant epilepsy. Inhibition of the mTOR pathway by rapamycin may be a potential therapeutic approach for pharmacoresistant epilepsy.
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Affiliation(s)
- Xiaosa Chi
- Department of Neurology, West China Hospital, Sichuan University, 37th Guoxuexiang Road, Chengdu, Sichuan Province, 610041, China
| | - Cheng Huang
- Department of Neurology, West China Hospital, Sichuan University, 37th Guoxuexiang Road, Chengdu, Sichuan Province, 610041, China
| | - Rui Li
- Key Lab of Transplant Engineering and Immunology, MOH, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Wei Wang
- Department of Neurology, West China Hospital, Sichuan University, 37th Guoxuexiang Road, Chengdu, Sichuan Province, 610041, China
| | - Mengqian Wu
- Department of Neurology, West China Hospital, Sichuan University, 37th Guoxuexiang Road, Chengdu, Sichuan Province, 610041, China
| | - Jinmei Li
- Department of Neurology, West China Hospital, Sichuan University, 37th Guoxuexiang Road, Chengdu, Sichuan Province, 610041, China
| | - Dong Zhou
- Department of Neurology, West China Hospital, Sichuan University, 37th Guoxuexiang Road, Chengdu, Sichuan Province, 610041, China.
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12
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Plasticity of Hippocampal Excitatory-Inhibitory Balance: Missing the Synaptic Control in the Epileptic Brain. Neural Plast 2016; 2016:8607038. [PMID: 27006834 PMCID: PMC4783563 DOI: 10.1155/2016/8607038] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/20/2016] [Accepted: 01/31/2016] [Indexed: 11/24/2022] Open
Abstract
Synaptic plasticity is the capacity generated by experience to modify the neural function and, thereby, adapt our behaviour. Long-term plasticity of glutamatergic and GABAergic transmission occurs in a concerted manner, finely adjusting the excitatory-inhibitory (E/I) balance. Imbalances of E/I function are related to several neurological diseases including epilepsy. Several evidences have demonstrated that astrocytes are able to control the synaptic plasticity, with astrocytes being active partners in synaptic physiology and E/I balance. Here, we revise molecular evidences showing the epileptic stage as an abnormal form of long-term brain plasticity and propose the possible participation of astrocytes to the abnormal increase of glutamatergic and decrease of GABAergic neurotransmission in epileptic networks.
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13
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Wilhelm I, Nyúl-Tóth Á, Suciu M, Hermenean A, Krizbai IA. Heterogeneity of the blood-brain barrier. Tissue Barriers 2016; 4:e1143544. [PMID: 27141424 DOI: 10.1080/21688370.2016.1143544] [Citation(s) in RCA: 160] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/08/2016] [Accepted: 01/12/2016] [Indexed: 01/08/2023] Open
Abstract
The brain microvascular network is comprised of capillaries, arterioles and venules, all of which retain - although to a different extent - blood-brain barrier (BBB) properties. Capillaries constitute the largest and tightest microvasculature. In contrast, venules have a looser junctional arrangement, while arterioles have a lower expression of P-gp. Development and maintenance of the BBB depends on the interaction of cerebral endothelial cells with pericytes and astrocytes, which are all heterogeneous in different regions of the central nervous system. At the level of circumventricular organs microvessels are permeable, containing fenestrations and discontinuous tight junctions. In addition, the blood-spinal cord barrier - where the number of pericytes is lower and expression of junctional proteins is reduced - is also more permeable than the BBB. However, much less is known about the cellular, molecular and functional differences among other regions of the brain. This review summarizes our current knowledge on the heterogeneity of the brain microvasculature.
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Affiliation(s)
- Imola Wilhelm
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences ; Szeged, Hungary
| | - Ádám Nyúl-Tóth
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences ; Szeged, Hungary
| | - Maria Suciu
- Institute of Life Sciences, Vasile Goldis Western University of Arad ; Arad, Romania
| | - Anca Hermenean
- Institute of Life Sciences, Vasile Goldis Western University of Arad ; Arad, Romania
| | - István A Krizbai
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences; Szeged, Hungary; Institute of Life Sciences, Vasile Goldis Western University of Arad; Arad, Romania
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14
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Shao Y, Wang C, Hong Z, Chen Y. Inhibition of p38 mitogen-activated protein kinase signaling reduces multidrug transporter activity and anti-epileptic drug resistance in refractory epileptic rats. J Neurochem 2016; 136:1096-105. [PMID: 26677173 DOI: 10.1111/jnc.13498] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 12/03/2015] [Accepted: 12/09/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Yiye Shao
- Department of Neurology; Jinshan Hospital; Fudan University; Shanghai China
- Department of Neurology; Shanghai Medical College; Fudan University; Shanghai China
| | - Cuicui Wang
- Department of Neurology; Jinshan Hospital; Fudan University; Shanghai China
- Department of Neurology; Shanghai Medical College; Fudan University; Shanghai China
| | - Zhen Hong
- Department of Neurology; Shanghai Medical College; Fudan University; Shanghai China
- Department of Neurology; Huashan Hospital; Fudan University; Shanghai China
| | - Yinghui Chen
- Department of Neurology; Jinshan Hospital; Fudan University; Shanghai China
- Department of Neurology; Shanghai Medical College; Fudan University; Shanghai China
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15
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Bauer M, Karch R, Zeitlinger M, Liu J, Koepp MJ, Asselin MC, Sisodiya SM, Hainfellner JA, Wadsak W, Mitterhauser M, Müller M, Pataraia E, Langer O. In vivo P-glycoprotein function before and after epilepsy surgery. Neurology 2014; 83:1326-31. [PMID: 25186858 PMCID: PMC4189097 DOI: 10.1212/wnl.0000000000000858] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Objectives: To study the functional activity of the multidrug efflux transporter P-glycoprotein (Pgp) at the blood-brain barrier of patients with temporal lobe epilepsy using (R)-[11C]verapamil (VPM)-PET before and after temporal lobe surgery to assess whether postoperative changes in seizure frequency and antiepileptic drug load are associated with changes in Pgp function. Methods: Seven patients with drug-resistant temporal lobe epilepsy underwent VPM-PET scans pre- and postsurgery. Patients were followed up for a median of 6 years (range 4–7) after surgery. Pgp immunoreactivity in surgically resected hippocampal specimens was determined with immunohistochemistry. Results: Optimal surgical outcome, defined as seizure freedom and withdrawal of antiepileptic drugs, was associated with higher temporal lobe Pgp function before surgery, higher Pgp-positive staining in surgically resected hippocampal specimens, and reduction in global Pgp function postoperatively, compared with nonoptimal surgery outcome. Conclusions: The data from our pilot study suggest that Pgp overactivity in epilepsy is dynamic, and complete seizure control and elimination of antiepileptic medication is associated with reversal of overactivity, although these findings will require confirmation in a larger patient cohort.
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Affiliation(s)
- Martin Bauer
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Rudolf Karch
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Markus Zeitlinger
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Joan Liu
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Matthias J Koepp
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Marie-Claude Asselin
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Sanjay M Sisodiya
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Johannes A Hainfellner
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Wolfgang Wadsak
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Markus Mitterhauser
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Markus Müller
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Ekaterina Pataraia
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria
| | - Oliver Langer
- From the Departments of Clinical Pharmacology (M.B., M.Z., M. Müller, O.L.) and Neurology (E.P.), Center for Medical Statistics, Informatics, and Intelligent Systems (R.K.), Institute of Neurology (J.A.H.), and Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (W.W., M. Mitterhauser), Medical University of Vienna, Austria; Department of Clinical and Experimental Epilepsy (J.L., M.J.K., S.M.S.), UCL Institute of Neurology, London; Epilepsy Society (M.J.K., S.M.S.), Chalfont St Peter, Buckinghamshire; Institute for Population Health Wolfson Molecular Imaging Centre (M.-C.A.), University of Manchester, MAHSC, UK; and Health and Environment Department (O.L.), AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria.
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van Vliet E, Aronica E, Gorter J. Role of blood–brain barrier in temporal lobe epilepsy and pharmacoresistance. Neuroscience 2014; 277:455-73. [DOI: 10.1016/j.neuroscience.2014.07.030] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 07/17/2014] [Accepted: 07/21/2014] [Indexed: 12/14/2022]
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Chan PS, Zhang C, Zuo Z, Kwan P, Baum L. In vitro transport assays of rufinamide, pregabalin, and zonisamide by human P-glycoprotein. Epilepsy Res 2014; 108:359-66. [DOI: 10.1016/j.eplepsyres.2014.01.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/13/2014] [Accepted: 01/20/2014] [Indexed: 01/16/2023]
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Avemary J, Salvamoser JD, Peraud A, Rémi J, Noachtar S, Fricker G, Potschka H. Dynamic regulation of P-glycoprotein in human brain capillaries. Mol Pharm 2013; 10:3333-41. [PMID: 23924183 DOI: 10.1021/mp4001102] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Considering its role as a major blood-brain barrier gatekeeper, the dynamic regulation of the efflux transporter P-glycoprotein is of considerable functional relevance. In particular, disease-associated alterations in transport function might affect central nervous system drug efficacy. Thus, targeting regulatory signaling cascades might render a basis for novel therapeutic approaches. Using capillaries freshly prepared from patient tissue resected during epilepsy surgery, we demonstrate dynamic regulation of P-glycoprotein in human brain capillaries. Glutamate proved to up-regulate P-glycoprotein efflux transport in a significant manner via endothelial NMDA receptors. Both inhibition of cyclooxygenase-2 and antagonism at the glycine-binding site of the NMDA receptor prevented the glutamate-mediated induction of P-glycoprotein transport function in human capillaries. In conclusion, the data argue against species differences in the signaling factors increasing endothelial P-glycoprotein transport function in response to glutamate exposure. Targeting of cyclooxygenase-2 and of the NMDA receptor glycine-binding site was confirmed as an efficacious approach to control P-glycoprotein function. The findings might render a basis for translational development of add-on approaches to improve brain penetration and efficacy of drugs.
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Affiliation(s)
- Janine Avemary
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University , 80539 Munich, Germany
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Potschka H. Animal and human data: where are our concepts for drug-resistant epilepsy going? Epilepsia 2013; 54 Suppl 2:29-32. [PMID: 23646968 DOI: 10.1111/epi.12181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Drug-resistant epilepsy remains a challenge in the therapeutic management of patients with epilepsy. Identification of factors contributing to drug resistance might render a basis for the development of novel therapeutic approaches, for the reorganization of screening programs in drug development, and for the design of personalized treatment concepts. Therefore, experimental and clinical studies need to link efforts and collaborate in order to elucidate drug-resistance mechanisms, to define the relative clinical relevance of selected mechanisms, and to develop and validate novel therapeutic concepts in overcoming resistance.
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Affiliation(s)
- Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Munich, Germany.
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Syvänen S, Russmann V, Verbeek J, Eriksson J, Labots M, Zellinger C, Seeger N, Schuit R, Rongen M, van Kooij R, Windhorst AD, Lammertsma AA, de Lange EC, Voskuyl RA, Koepp M, Potschka H. [11C]quinidine and [11C]laniquidar PET imaging in a chronic rodent epilepsy model: impact of epilepsy and drug-responsiveness. Nucl Med Biol 2013; 40:764-75. [PMID: 23827307 DOI: 10.1016/j.nucmedbio.2013.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/24/2013] [Accepted: 05/23/2013] [Indexed: 10/26/2022]
Abstract
INTRODUCTION To analyse the impact of both epilepsy and pharmacological modulation of P-glycoprotein on brain uptake and kinetics of positron emission tomography (PET) radiotracers [(11)C]quinidine and [(11)C]laniquidar. METHODS Metabolism and brain kinetics of both [(11)C]quinidine and [(11)C]laniquidar were assessed in naive rats, electrode-implanted control rats, and rats with spontaneous recurrent seizures. The latter group was further classified according to their response to the antiepileptic drug phenobarbital into "responders" and "non-responders". Additional experiments were performed following pre-treatment with the P-glycoprotein modulator tariquidar. RESULTS [(11)C]quinidine was metabolized rapidly, whereas [(11)C]laniquidar was more stable. Brain concentrations of both radiotracers remained at relatively low levels at baseline conditions. Tariquidar pre-treatment resulted in significant increases of [(11)C]quinidine and [(11)C]laniquidar brain concentrations. In the epileptic subgroup "non-responders", brain uptake of [(11)C]quinidine in selected brain regions reached higher levels than in electrode-implanted control rats. However, the relative response to tariquidar did not differ between groups with full blockade of P-glycoprotein by 15 mg/kg of tariquidar. For [(11)C]laniquidar differences between epileptic and control animals were only evident at baseline conditions but not after tariquidar pretreatment. CONCLUSIONS We confirmed that both [(11)C]quinidine and [(11)C]laniquidar are P-glycoprotein substrates. At full P-gp blockade, tariquidar pre-treatment only demonstrated slight differences for [(11)C]quinidine between drug-resistant and drug-sensitive animals.
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Affiliation(s)
- Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
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Muñana K, Nettifee-Osborne J, Bergman R, Mealey K. Association between ABCB1 Genotype and Seizure Outcome in Collies with Epilepsy. J Vet Intern Med 2012; 26:1358-64. [DOI: 10.1111/j.1939-1676.2012.01006.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Revised: 06/13/2012] [Accepted: 08/15/2012] [Indexed: 01/02/2023] Open
Affiliation(s)
- K.R. Muñana
- Department of Clinical Sciences; College of Veterinary Medicine, North Carolina State University; Raleigh; NC
| | - J.A. Nettifee-Osborne
- Department of Clinical Sciences; College of Veterinary Medicine, North Carolina State University; Raleigh; NC
| | - R.L. Bergman
- Department of Clinical Sciences; College of Veterinary Medicine, North Carolina State University; Raleigh; NC
| | - K.L. Mealey
- Department of Veterinary Clinical Sciences; College of Veterinary Medicine, Washington State University; Pullman; WA
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Potschka H. Role of CNS efflux drug transporters in antiepileptic drug delivery: overcoming CNS efflux drug transport. Adv Drug Deliv Rev 2012; 64:943-52. [PMID: 22210135 DOI: 10.1016/j.addr.2011.12.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 12/11/2011] [Accepted: 12/12/2011] [Indexed: 01/16/2023]
Abstract
Experimental support for the transporter hypothesis of drug resistance in epilepsies has triggered efforts developing and validating approaches to overcome enhanced blood-brain barrier efflux transport. Testing in rodent models has rendered proof-of-concept for an add-on therapy with antiepileptic drugs. However, further development of the approach would require tolerability considerations as efflux transporters serve an important protective function throughout the body limiting distribution of harmful xenobiotics. Relevant progress has been made in the elucidation of mechanisms driving up-regulation of the multidrug transporter P-glycoprotein in response to seizure activity. Based on this knowledge, novel strategies have been evaluated targeting the signaling cascade that regulates P-glycoprotein in the epileptic brain. Further concepts might include by-passing blood-brain barrier transporters by intracerebral administration or by encapsulation of antiepileptic drugs in nano-sized carrier systems. It is important to note that the future perspectives of respective approaches are still questionable based on the limited evidence for a clinical relevance of transporter expression. Thus, techniques are urgently needed for non-invasive assessment of blood-brain barrier transporter function. Respective techniques would allow testing for a clinical correlation between pharmacosensitivity and transporter function, validating therapeutic strategies targeting efflux transporters and selecting patients with transporter over-expression for respective clinical trials. Provided that further clinical data render support for the transporter hypothesis, the main question remains whether patients exist in which transporter over-expression is the predominant mechanism of drug resistance and in which overcoming drug efflux is equivalent with overcoming drug resistance. Imaging techniques might provide a tool to address these questions in clinical epileptology. However, the complex pharmacological interactions between antiepileptic drugs, radiotracers, and transporter modulators used in these approaches as well as interindividual differences in the brain pathology might hamper clear-cut conclusions and limit the diagnostic significance.
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Zhang C, Kwan P, Zuo Z, Baum L. The transport of antiepileptic drugs by P-glycoprotein. Adv Drug Deliv Rev 2012; 64:930-42. [PMID: 22197850 DOI: 10.1016/j.addr.2011.12.003] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2011] [Revised: 12/05/2011] [Accepted: 12/07/2011] [Indexed: 01/16/2023]
Abstract
Epilepsy is the most common serious chronic neurological disorder. Current data show that one-third of patients do not respond to anti-epileptic drugs (AEDs). Most non-responsive epilepsy patients are resistant to several, often all, AEDs, even though the drugs differ from each other in pharmacokinetics, mechanisms of action, and interaction potential. The mechanisms underlying drug resistance of epilepsy patients are still not clear. In recent years, one of the potential mechanisms interesting researchers is over-expression of P-glycoprotein (P-gp, also known as ABCB1 or MDR1) in endothelial cells of the blood-brain barrier (BBB) in epilepsy patients. P-gp plays a central role in drug absorption and distribution in many organisms. The expression of P-gp is greater in drug-resistant than in drug-responsive patients. Some studies also indicate that several AEDs are substrates or inhibitors of P-gp, implying that P-gp may play an important role in drug resistance in refractory epilepsy. In this article, we review the clinical and laboratory evidence that P-gp expression is increased in epileptic brain tissues and that AEDs are substrates of P-gp in vitro and in vivo. We discuss criteria for identifying the substrate status of AEDs and use structure-activity relationship (SAR) models to predict which AEDs act as P-gp substrates.
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Adams SJ, Velakoulis D, Kaye AH, Corcoran NM, O’Brien TJ. Psychiatric history does not predict seizure outcome following temporal lobectomy for mesial temporal sclerosis. Epilepsia 2012; 53:1700-4. [DOI: 10.1111/j.1528-1167.2012.03569.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Affiliation(s)
- Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Therapeutics, Ludwig-Maximilians-University, Munich, Germany.
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Munster BCV, Aronica E, Zwinderman AH, Eikelenboom P, Cunningham C, Rooij SEJAD. Neuroinflammation in delirium: a postmortem case-control study. Rejuvenation Res 2011; 14:615-22. [PMID: 21978081 DOI: 10.1089/rej.2011.1185] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Delirium can be hypothesized to be an extreme manifestation of sickness behavior in elderly persons with neurodegenerative disease. The purpose of this study was to investigate whether increased cerebral inflammation with microglial, astrocyte, and cytokine activation exists in patients with delirium compared to nondelirious patients. METHODS Postmortem brain tissue from 9 cases with delirium was compared to 6 age-matched controls without delirium. Human leukocyte antigen-DR (HLA-DR) and CD68 cell count and glial fibrillary acidic protein (GFAP), interleukin-1β (IL-1β), IL-6,β-amyloid, and tau protein immunoreactivity were determined in hippocampus, frontal cortex, and white matter. RESULTS There were no significant differences in the patients with delirium compared to the controls with respect to age 73 versus 70.5 years (p=0.72) or dementia (22% versus 0%, p=0.22). Both markers for microglial activity showed significantly higher scores in delirium brain specimens than controls in the total brain score (HLA-DR 129 vs. 20 and CD68 30 vs. 8.5) as well as in the various brain areas separately. The immunoreactivity of astrocyte activity (GFAP) was higher in the total brain score in patients with delirium (5.2 vs. 4.0, p=0.05), but in the various brain areas this was only significant in the dentate gyrus. IL-6 immunoreactivity was higher in patients with delirium in all brain areas and IL-1β was not detectable. Coexisting infectious disease or dementia did not influence the overall results. CONCLUSIONS These preliminary study results show an association between human brain activity of microglia, astrocytes, and IL-6 and delirium in elderly patients and add to the accumulating evidence that inflammatory mechanisms are involved in delirium.
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Affiliation(s)
- Barbara C van Munster
- Department of Internal Medicine, Academic Medical Center, University of Amsterdam, P.O. Box 22660, 1100 DD Amsterdam, The Netherlands.
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Potschka H. Transporter hypothesis of drug-resistant epilepsy: challenges for pharmacogenetic approaches. Pharmacogenomics 2011; 11:1427-38. [PMID: 21047204 DOI: 10.2217/pgs.10.126] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Drug resistance in epilepsy is considered a complex and multifactorial problem. Overexpression of efflux transporters at the blood-brain barrier is discussed as one factor that might limit brain penetration and efficacy of antiepileptic drugs. Whereas experimental data render support for this hypothesis, there is still a lack of sufficient clinical evidence indicating a functional role of efflux transporters. Pharmacogenetic analysis has been considered as one approach in the evaluation of a putative link between transporters and drug-resistant epilepsy. However, the likelihood of a multifactorial nature of drug resistance and the complexity of the events regulating transporters pose a major challenge to any attempt at linking selected genetic polymorphisms to the outcome of drug therapy. In this article, the evidence for an impact of efflux transporters on the response to antiepileptic drugs is discussed, focusing in particular on the different issues presenting a challenge for pharmacogenetic approaches in this field.
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Affiliation(s)
- Heidrun Potschka
- Institute of Pharmacology, Toxicology & Pharmacy, Ludwig-Maximilians-University, Koeniginstr. 16, D-80539 Munich, Germany.
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