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Ilyas-Feldmann M, Langer O, Bauer M, Asselin MC, Hendrikse NH, Sisodiya SM, Duncan JS, Löscher W, Koepp M. Tolerability of tariquidar - A third generation P-gp inhibitor as add-on medication to antiseizure medications in drug-resistant epilepsy. Seizure 2024; 119:44-51. [PMID: 38776617 DOI: 10.1016/j.seizure.2024.05.007] [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: 03/28/2024] [Revised: 05/10/2024] [Accepted: 05/12/2024] [Indexed: 05/25/2024] Open
Abstract
PURPOSE P-glycoprotein (P-gp) has been hypothesized to be involved in drug-resistance of epilepsy by actively extruding antiseizure medications (ASMs) from the brain. The P-gp inhibitor tariquidar (TQD) has been shown to effectively inhibit P-gp at the human blood-brain barrier, improving brain entry of several ASMs. A potential strategy to overcome drug-resistance is the co-administration of P-gp inhibitors such as TQD to ASMs. Here we present data on the tolerability of single-dose TQD as a potential add-on medication to ASMs. METHODS We performed a multi-centre cohort study including drug-resistant epilepsy patients and healthy controls from the United Kingdom and Austria. TQD was administered intravenously at five different doses (2 mg/kg or 3 mg/kg of TQD were given to drug-resistant epilepsy patients and healthy controls, higher doses of TQD at 4 mg/kg, 6 mg/kg and 8 mg/kg as well as a prolonged infusion aiming at a dose of 6 mg/kg were only given to healthy controls). Adverse events were recorded and graded using the Common Terminology Criteria (CTCAE) scale. Additionally, TQD plasma concentration levels were measured and compared between drug-resistant patients and healthy controls. RESULTS In total, 108 participants received TQD once at variable doses and it was overall well tolerated. At doses of 2 or 3 mg/kg TQD, only two of the 19 drug-resistant epilepsy patients and a third of the healthy controls (n = 14/42) reported adverse events probably related to TQD. The majority of those adverse events (96 %) were reported as mild. One drug-resistant epilepsy patient reported adverse events 24-hours after TQD administration possibly related to TQD-induced increased ASMs levels in the brain. CONCLUSIONS TQD is an effective and well tolerated P-gp inhibitor as a single dose and could potentially be used intermittently in conjunction with ASMs to improve efficacy. This promising strategy to overcome drug-resistance in epilepsy should be investigated further in clinical randomised controlled trials.
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Affiliation(s)
- Maria Ilyas-Feldmann
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, United Kingdom and Chalfont Centre for Epilepsy, Bucks SL9 0RJ, United Kingdom; Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom; Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neurology with Experimental Neurology, Berlin, Germany.
| | - Oliver Langer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria; Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Martin Bauer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria; Psychosocial Services in Vienna, Vienna, Austria
| | - Marie-Claude Asselin
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom; Division of Informatics, Imaging & Data Science, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, United Kingdom
| | - N Harry Hendrikse
- Department of Radiology and Nuclear Medicine, University of Amsterdam, Amsterdam UMC, Amsterdam, the Netherlands
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, United Kingdom and Chalfont Centre for Epilepsy, Bucks SL9 0RJ, United Kingdom
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, United Kingdom and Chalfont Centre for Epilepsy, Bucks SL9 0RJ, United Kingdom
| | - Wolfgang Löscher
- Translational Neuropharmacology Lab, NIFE, Department of Experimental Otology of the ENT Clinics, Hannover Medical School, Hannover, Germany
| | - Matthias Koepp
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, United Kingdom and Chalfont Centre for Epilepsy, Bucks SL9 0RJ, United Kingdom
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Villa M, Wu J, Hansen S, Pahnke J. Emerging Role of ABC Transporters in Glia Cells in Health and Diseases of the Central Nervous System. Cells 2024; 13:740. [PMID: 38727275 PMCID: PMC11083179 DOI: 10.3390/cells13090740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/15/2024] [Accepted: 04/20/2024] [Indexed: 05/13/2024] Open
Abstract
ATP-binding cassette (ABC) transporters play a crucial role for the efflux of a wide range of substrates across different cellular membranes. In the central nervous system (CNS), ABC transporters have recently gathered significant attention due to their pivotal involvement in brain physiology and neurodegenerative disorders, such as Alzheimer's disease (AD). Glial cells are fundamental for normal CNS function and engage with several ABC transporters in different ways. Here, we specifically highlight ABC transporters involved in the maintenance of brain homeostasis and their implications in its metabolic regulation. We also show new aspects related to ABC transporter function found in less recognized diseases, such as Huntington's disease (HD) and experimental autoimmune encephalomyelitis (EAE), as a model for multiple sclerosis (MS). Understanding both their impact on the physiological regulation of the CNS and their roles in brain diseases holds promise for uncovering new therapeutic options. Further investigations and preclinical studies are warranted to elucidate the complex interplay between glial ABC transporters and physiological brain functions, potentially leading to effective therapeutic interventions also for rare CNS disorders.
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Affiliation(s)
- Maria Villa
- Translational Neurodegeneration Research and Neuropathology Lab, Department of Clinical Medicine (KlinMed), Medical Faculty, University of Oslo (UiO) and Section of Neuropathology Research, Department of Pathology (PAT), Clinics for Laboratory Medicine (KLM), Oslo University Hospital (OUS), Sognsvannsveien 20, NO-0372 Oslo, Norway
| | - Jingyun Wu
- Translational Neurodegeneration Research and Neuropathology Lab, Department of Clinical Medicine (KlinMed), Medical Faculty, University of Oslo (UiO) and Section of Neuropathology Research, Department of Pathology (PAT), Clinics for Laboratory Medicine (KLM), Oslo University Hospital (OUS), Sognsvannsveien 20, NO-0372 Oslo, Norway
| | - Stefanie Hansen
- Translational Neurodegeneration Research and Neuropathology Lab, Department of Clinical Medicine (KlinMed), Medical Faculty, University of Oslo (UiO) and Section of Neuropathology Research, Department of Pathology (PAT), Clinics for Laboratory Medicine (KLM), Oslo University Hospital (OUS), Sognsvannsveien 20, NO-0372 Oslo, Norway
| | - Jens Pahnke
- Translational Neurodegeneration Research and Neuropathology Lab, Department of Clinical Medicine (KlinMed), Medical Faculty, University of Oslo (UiO) and Section of Neuropathology Research, Department of Pathology (PAT), Clinics for Laboratory Medicine (KLM), Oslo University Hospital (OUS), Sognsvannsveien 20, NO-0372 Oslo, Norway
- Institute of Nutritional Medicine (INUM)/Lübeck Institute of Dermatology (LIED), University of Lübeck (UzL) and University Medical Center Schleswig-Holstein (UKSH), Ratzeburger Allee 160, D-23538 Lübeck, Germany
- Department of Pharmacology, Faculty of Medicine, University of Latvia (LU), Jelgavas iela 3, LV-1004 Rīga, Latvia
- School of Neurobiology, Biochemistry and Biophysics, The Georg S. Wise Faculty of Life Sciences, Tel Aviv University (TAU), Tel Aviv IL-6997801, Israel
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Kaur M, Gupta T, Gupta M, Singla N, Kharbanda PS, Bansal YS, Sahni D, Radotra BD, Gupta SK. Expressional Study of Permeability Glycoprotein and Multidrug Resistance Protein 1 in Drug-resistant Mesial Temporal Lobe Epilepsy. Basic Clin Neurosci 2023; 14:615-630. [PMID: 38628830 PMCID: PMC11016880 DOI: 10.32598/bcn.2021.2554.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/09/2021] [Accepted: 07/27/2023] [Indexed: 04/19/2024] Open
Abstract
Introduction About 30% of patients with epilepsy do not respond to anti-epileptic drugs, leading to refractory seizures. The pathogenesis of drug-resistance in mesial temporal lobe epilepsy (MTLE) is not completely understood. Increased activity of drug-efflux transporters might be involved, resulting in subclinical concentrations of the drug at the target site. The major drug-efflux transporters are permeability glycoprotein (P-gp) and multidrug-resistance associated protein-1 (MRP-1). The major drawback so far is the expressional analysis of transporters in equal numbers of drug-resistant epileptic tissue and age-matched non-epileptic tissue. Methods We have studied P-gp and MRP-1 drug-efflux transporters in the sclerotic hippocampal tissues resected from the epilepsy surgery patients (n=15) and compared their expression profile with the tissues resected from non-epileptic autopsy cases (n=15). Results Statistically significant over expression of both P-gp (P<0.0001) and MRP-1 (P=0.01) at gene and protein levels were found in the MTLE cases. The fold change of P-gp was more pronounced than MRP-1. Immunohistochemistry of the patient group showed increased immunoreactivity of P-gp at blood-brain barrier and increased reactivity of MRP-1 in the parenchyma. The results were confirmed by confocal immunofluorescence microscopy. Conclusion Our results suggested that P-gp in association with MRP-1 might be responsible for the multi-drug resistance in epilepsy. P-gp and MRP-1 could be important determinants of bio availability and tissue distribution of anti-epileptic drugs in the brain which can pharmacologically inhibited to achieve optimal drug penetration to target site.
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Affiliation(s)
- Mandeep Kaur
- Department of Anatomy, Institute of Medical Education and Research, Chandigarh, India
| | - Tulika Gupta
- Department of Anatomy, Institute of Medical Education and Research, Chandigarh, India
| | - Mili Gupta
- Department of Biochemistry, Singh Judge Institute of Dental Sciences and Hospital, Panjab University, Chandigarh, India
| | - Navneet Singla
- Department of Neurosurgery, Institute of Medical Education and Research, Chandigarh, India
| | | | - Yogender Singh Bansal
- Department of Forensic Medicine, Institute of Medical Education and Research, Chandigarh, India
| | - Daisy Sahni
- Department of Anatomy, Institute of Medical Education and Research, Chandigarh, India
| | - Bishan Das Radotra
- Department of Histopathology, Institute of Medical Education and Research, Chandigarh, India
| | - Sunil Kumar Gupta
- Department of Neurosurgery, Institute of Medical Education and Research, Chandigarh, India
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Sukprakun C, Tepmongkol S. Nuclear imaging for localization and surgical outcome prediction in epilepsy: A review of latest discoveries and future perspectives. Front Neurol 2022; 13:1083775. [PMID: 36588897 PMCID: PMC9800996 DOI: 10.3389/fneur.2022.1083775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 11/25/2022] [Indexed: 12/23/2022] Open
Abstract
Background Epilepsy is one of the most common neurological disorders. Approximately, one-third of patients with epilepsy have seizures refractory to antiepileptic drugs and further require surgical removal of the epileptogenic region. In the last decade, there have been many recent developments in radiopharmaceuticals, novel image analysis techniques, and new software for an epileptogenic zone (EZ) localization. Objectives Recently, we provided the latest discoveries, current challenges, and future perspectives in the field of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) in epilepsy. Methods We searched for relevant articles published in MEDLINE and CENTRAL from July 2012 to July 2022. A systematic literature review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis was conducted using the keywords "Epilepsy" and "PET or SPECT." We included both prospective and retrospective studies. Studies with preclinical subjects or not focusing on EZ localization or surgical outcome prediction using recently developed PET radiopharmaceuticals, novel image analysis techniques, and new software were excluded from the review. The remaining 162 articles were reviewed. Results We first present recent findings and developments in PET radiopharmaceuticals. Second, we present novel image analysis techniques and new software in the last decade for EZ localization. Finally, we summarize the overall findings and discuss future perspectives in the field of PET and SPECT in epilepsy. Conclusion Combining new radiopharmaceutical development, new indications, new techniques, and software improves EZ localization and provides a better understanding of epilepsy. These have proven not to only predict prognosis but also to improve the outcome of epilepsy surgery.
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Affiliation(s)
- Chanan Sukprakun
- Division of Nuclear Medicine, Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Supatporn Tepmongkol
- Division of Nuclear Medicine, Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand,Chulalongkorn University Biomedical Imaging Group (CUBIG), Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand,Chula Neuroscience Center, King Chulalongkorn Memorial Hospital, Bangkok, Thailand,Cognitive Impairment and Dementia Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand,*Correspondence: Supatporn Tepmongkol ✉
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Louis S, Busch RM, Lal D, Hockings J, Hogue O, Morita-Sherman M, Vegh D, Najm I, Ghosh C, Bazeley P, Eng C, Jehi L, Rotroff DM. Genetic and molecular features of seizure-freedom following surgical resections for focal epilepsy: A pilot study. Front Neurol 2022; 13:942643. [PMID: 36188379 PMCID: PMC9524264 DOI: 10.3389/fneur.2022.942643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 08/08/2022] [Indexed: 11/23/2022] Open
Abstract
Objective Seizure outcomes after brain surgery for drug-resistant epilepsy (DRE) are very heterogeneous and difficult to predict with models utilizing the current clinical, imaging, and electrophysiological variables. In this pilot study, we investigated whether genetic and molecular biomarkers (e.g., genomic, transcriptomic) can provide additional insight into differential response to surgery. Methods Post-operative seizure-outcomes were collected at last follow-up (>6 months) for 201 adult patients with DRE who underwent surgery between 2004 and 2020. Resected tissue was sent for miRNA sequencing (n = 132) and mRNA sequencing (n = 135). Following the selection of 10 genes (SCN1A, NBEA, PTEN, GABRA1, LGL1, DEPDC5, IL1A, ABCB1, C3, CALHM1), we investigated SNPs in those 10 genes from previously acquired exome sequencing data (n = 106). Logistic regression was performed to test for associations between individual features (mRNAs, miRNAs, and SNPs) and post-operative seizure-outcome with an exploratory FDR P < 0.25 as the threshold for significance. Post-operative time-to-seizure analyses were performed for each SNP using a Cox proportional hazards model. Results The majority of patients (83%) had temporal lobe epilepsy. Mean age at surgery was 38.3 years, and 56% were female. Three SNPs (rs10276036, rs11975994, rs1128503) in multi-drug resistance gene, ABCB1, were associated with post-operative seizure outcomes. Patients with alternate alleles in ABCB1 were more likely to be seizure-free at last follow-up (52–56% reduction in seizure recurrence; FDR P = 0.24). All three SNPs were in linkage disequilibrium and highly correlated with each other. Median post-operative time-to-seizure was 63 months for patients with 2 alternate alleles, 24–33 months with 1 alternate allele, and 10–11 months with 0 alternate alleles. These SNPs improved outcome prediction beyond MRI and sex alone. No independent miRNAs or mRNAs were significantly associated with seizure-outcome (P > 0.05). However, pathway analysis identified “cancer drug resistance by drug efflux” (mir-154 and mir-379) as enriched (P = 0.02), supporting the role of drug response genes in post-operative seizure recurrence. Significance ABCB1 may have a role in epileptogenesis and surgery outcomes independent of its drug efflux activity necessitating further investigation. SNPs in ABCB1 may serve as independent predictors of post-operative outcome.
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Affiliation(s)
- Shreya Louis
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
| | - Robyn M. Busch
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Dennis Lal
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Jennifer Hockings
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Center for Personalized Genetic Healthcare, Community Care and Population Health, Cleveland Clinic, Cleveland, OH, United States
- Department of Pharmacy, Cleveland Clinic, Cleveland, OH, United States
| | - Olivia Hogue
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Marcia Morita-Sherman
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Deborah Vegh
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Imad Najm
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Chaitali Ghosh
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Peter Bazeley
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Charis Eng
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Center for Personalized Genetic Healthcare, Community Care and Population Health, Cleveland Clinic, Cleveland, OH, United States
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Lara Jehi
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Lara Jehi
| | - Daniel M. Rotroff
- Cleveland Clinic Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, United States
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Endocrinology and Metabolism Institute, Cleveland Clinic, Cleveland, OH, United States
- *Correspondence: Daniel M. Rotroff
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Dose-response assessment of cerebral P-glycoprotein inhibition in vivo with [ 18F]MC225 and PET. J Control Release 2022; 347:500-507. [PMID: 35588934 DOI: 10.1016/j.jconrel.2022.05.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/09/2022] [Accepted: 05/11/2022] [Indexed: 11/20/2022]
Abstract
The Blood-Brain Barrier P-glycoprotein (P-gp) function can be altered in several neurodegenerative diseases and due to the administration of different drugs which may cause alterations in drug concentrations and consequently lead to a reduced effectiveness or increased side-effects. The novel PET radiotracer [18F]MC225 is a weak P-gp substrate that may show higher sensitivity to detect small changes in P-gp function than previously developed radiotracers. This study explores the sensitivity of [18F]MC225 to measure the dose-dependent effect of P-gp inhibitor tariquidar. Twenty-three rats were intravenously injected with different doses of tariquidar ranging from 0.75 to 12 mg/kg, 30-min before the dynamic [18F]MC225-PET acquisition with arterial sampling. Tissue and blood data were fitted to a 1-Tissue-Compartment-Model to obtain influx constant K1 and distribution volume VT, which allow the estimation of P-gp function. ANOVA and post-hoc analyses of K1 values showed significant differences between controls and groups with tariquidar doses >3 mg/kg; while applying VT the analyses showed significant differences between controls and groups with tariquidar doses >6 mg/kg. Dose-response curves were fitted using different models. The four-parameter logistic sigmoidal curve provided the best fit for K1 and VT data. Half-maximal inhibitory doses (ID50) were 2.23 mg/kg (95%CI: 1.669-2.783) and 2.93 mg/kg (95%CI: 1.135-3.651), calculated with K1 or VT values respectively. According to the dose-response fit, differences in [18F]MC225-K1 values could be detected at tariquidar doses ranging from 1.37 to 3.25 mg/kg. Our findings showed that small changes in the P-gp function, caused by low doses of tariquidar, could be detected by [18F]MC225-K1 values, which confirms the high sensitivity of the radiotracer. The results suggest that [18F]MC225 may allow the quantification of moderate P-gp impairments, which may allow the detection of P-gp dysfunctions at the early stages of a disease and potential transporter-mediated drug-drug interactions.
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Brukner AM, Billington S, Benifla M, Nguyen TB, Han H, Bennett O, Gilboa T, Blatch D, Fellig Y, Volkov O, Unadkat JD, Ekstein D, Eyal S. Abundance of P-glycoprotein and Breast Cancer Resistance Protein Measured by Targeted Proteomics in Human Epileptogenic Brain Tissue. Mol Pharm 2021; 18:2263-2273. [PMID: 34008992 PMCID: PMC8488956 DOI: 10.1021/acs.molpharmaceut.1c00083] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Our goal was to measure the absolute
differential abundance of
key drug transporters in human epileptogenic brain tissue and to compare
them between patients and at various distances from the epileptogenic
zone within the same patient. Transporter protein abundance was quantified
in brain tissue homogenates from patients who underwent epilepsy surgery,
using targeted proteomics, and correlations with clinical and tissue
characteristics were assessed. Fourteen brain samples (including four
epileptogenic hippocampal samples) were collected from nine patients.
Among the quantifiable drug transporters, the abundance (median, range)
ranked: breast cancer resistance protein (ABCG2/BCRP; 0.55, 0.01–3.26
pmol/g tissue) > P-glycoprotein (ABCB1/MDR1; 0.30,
0.02–1.15 pmol/g tissue) > equilibrative nucleoside transporter
1 (SLC29A1/ENT1; 0.06, 0.001–0.35 pmol/g tissue). The ABCB1/ABCG2
ratio (mean 0.27, range 0.08–0.47) was comparable with literature
values from nonepileptogenic brain tissue (mean 0.5–0.8). Transporter
abundance was lower in the hippocampi than in the less epileptogenic
neocortex of the same patients. ABCG2/BCRP and ABCB1/MDR1 expression
strongly correlated with that of glucose transporter 1 (SLC2A1/GLUT1)
(r = 0.97, p < 0.001; r = 0.90, p < 0.01, respectively). Low
transporter abundance was found in patients with overt vascular pathology,
whereas the highest abundance was seen in a sample with normally appearing
blood vessels. In conclusion, drug transporter abundance highly varies
across patients and between epileptogenic and less epileptogenic brain
tissue of the same patient. The strong correlation in abundance of
ABCB1/MDR1, ABCG2/BCRP, and SLC2A1/GLUT1 suggests variation in the
content of the functional vasculature within the tissue samples. The
epileptogenic tissue can be depleted of key drug transport mechanisms,
warranting consideration when selecting treatments for patients with
drug-resistant epilepsy.
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Affiliation(s)
- Aniv Mann Brukner
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Room 613, Ein Kerem, Jerusalem 91120, Israel
| | - Sarah Billington
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington 98195, United States
| | - Mony Benifla
- Children's Neurosurgery Department, Rambam Academic Hospital, Haifa 31999, Israel
| | - Tot Bui Nguyen
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington 98195, United States
| | - Hadas Han
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Room 613, Ein Kerem, Jerusalem 91120, Israel
| | - Odeya Bennett
- Department of Pediatrics, Shaare Zedek Medical Center, Jerusalem 91031, Israel
| | - Tal Gilboa
- Neuropediatric Unit, Pediatrics Division, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel.,The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Dana Blatch
- Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah Medical Organization, Jerusalem 91120, Israel
| | - Yakov Fellig
- The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.,Department of Pathology, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Olga Volkov
- Nuclear Medicine Institute, Sheba Medical Center, Tel Hashomer 52621, Israel
| | - Jashvant D Unadkat
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, Washington 98195, United States
| | - Dana Ekstein
- The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.,Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah Medical Organization, Jerusalem 91120, Israel
| | - Sara Eyal
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Room 613, Ein Kerem, Jerusalem 91120, Israel
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Juvale IIA, Che Has AT. Possible interplay between the theories of pharmacoresistant epilepsy. Eur J Neurosci 2020; 53:1998-2026. [PMID: 33306252 DOI: 10.1111/ejn.15079] [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: 08/22/2020] [Revised: 11/22/2020] [Accepted: 12/04/2020] [Indexed: 02/06/2023]
Abstract
Epilepsy is one of the oldest known neurological disorders and is characterized by recurrent seizure activity. It has a high incidence rate, affecting a broad demographic in both developed and developing countries. Comorbid conditions are frequent in patients with epilepsy and have detrimental effects on their quality of life. Current management options for epilepsy include the use of anti-epileptic drugs, surgery, or a ketogenic diet. However, more than 30% of patients diagnosed with epilepsy exhibit drug resistance to anti-epileptic drugs. Further, surgery and ketogenic diets do little to alleviate the symptoms of patients with pharmacoresistant epilepsy. Thus, there is an urgent need to understand the underlying mechanisms of pharmacoresistant epilepsy to design newer and more effective anti-epileptic drugs. Several theories of pharmacoresistant epilepsy have been suggested over the years, the most common being the gene variant hypothesis, network hypothesis, multidrug transporter hypothesis, and target hypothesis. In our review, we discuss the main theories of pharmacoresistant epilepsy and highlight a possible interconnection between their mechanisms that could lead to the development of novel therapies for pharmacoresistant epilepsy.
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Affiliation(s)
- Iman Imtiyaz Ahmed Juvale
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Ahmad Tarmizi Che Has
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
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García-Varela L, García DV, Kakiuchi T, Ohba H, Nishiyama S, Tago T, Elsinga PH, Tsukada H, Colabufo NA, Dierckx RAJO, van Waarde A, Toyohara J, Boellaard R, Luurtsema G. Pharmacokinetic Modeling of ( R)-[ 11C]verapamil to Measure the P-Glycoprotein Function in Nonhuman Primates. Mol Pharm 2020; 18:416-428. [PMID: 33315404 PMCID: PMC7788571 DOI: 10.1021/acs.molpharmaceut.0c01014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
(R)-[11C]verapamil is a radiotracer
widely used for the evaluation of the P-glycoprotein (P-gp) function
at the blood–brain barrier (BBB). Several studies have evaluated
the pharmacokinetics of (R)-[11C]verapamil
in rats and humans under different conditions. However, to the best
of our knowledge, the pharmacokinetics of (R)-[11C]verapamil have not yet been evaluated in nonhuman primates.
Our study aims to establish (R)-[11C]verapamil
as a reference P-gp tracer for comparison of a newly developed P-gp
positron emission tomography (PET) tracer in a species close to humans.
Therefore, the study assesses the kinetics of (R)-[11C]verapamil and evaluates the effect of scan duration and
P-gp inhibition on estimated pharmacokinetic parameters. Three nonhuman
primates underwent two dynamic 91 min PET scans with arterial blood
sampling, one at baseline and another after inhibition of the P-gp
function. The (R)-[11C]verapamil data
were analyzed using 1-tissue compartment model (1-TCM) and 2-tissue
compartment model fits using plasma-corrected for polar radio-metabolites
or non-corrected for radio-metabolites as an input function and with
various scan durations (10, 20, 30, 60, and 91 min). The preferred
model was chosen according to the Akaike information criterion and
the standard errors (SE %) of the estimated parameters. 1-TCM was
selected as the model of choice to analyze the (R)-[11C]verapamil data at baseline and after inhibition
and for all scan durations tested. The volume of distribution (VT) and the efflux constant k2 estimations were affected by the evaluated scan durations,
whereas the influx constant K1 estimations
remained relatively constant. After P-gp inhibition (tariquidar, 8
mg/kg), in a 91 min scan duration, the whole-brain VT increased significantly up to 208% (p < 0.001) and K1 up to 159% (p < 0.001) compared with baseline scans. The k2 values decreased significantly after P-gp
inhibition in all the scan durations except for the 91 min scans.
This study suggests the use of K1, calculated
with 1-TCM and using short PET scans (10 to 30 min), as a suitable
parameter to measure the P-gp function at the BBB of nonhuman primates.
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Affiliation(s)
- Lara García-Varela
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - David Vállez García
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - Takeharu Kakiuchi
- Central Research Laboratory, Hamamatsu Photonics KK, 5000 Hirakuchi, Hamakita, Hamamatsu 434-8601, Shizuoka, Japan
| | - Hiroyuki Ohba
- Central Research Laboratory, Hamamatsu Photonics KK, 5000 Hirakuchi, Hamakita, Hamamatsu 434-8601, Shizuoka, Japan
| | - Shingo Nishiyama
- Central Research Laboratory, Hamamatsu Photonics KK, 5000 Hirakuchi, Hamakita, Hamamatsu 434-8601, Shizuoka, Japan
| | - Tetsuro Tago
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Philip H Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - Hideo Tsukada
- Central Research Laboratory, Hamamatsu Photonics KK, 5000 Hirakuchi, Hamakita, Hamamatsu 434-8601, Shizuoka, Japan
| | - Nicola A Colabufo
- Department of Pharmacy, University of Bari Aldo Moro, Bari 70125, Italy.,Biofordrug, Spin-off Università degli Studi di Bari "A. Moro", via Dante 99, Triggiano, Bari 70019, Italy
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan
| | - Ronald Boellaard
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
| | - Gert Luurtsema
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. Box 30001, Groningen 9713 GZ, The Netherlands
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10
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Löscher W, Potschka H, Sisodiya SM, Vezzani A. Drug Resistance in Epilepsy: Clinical Impact, Potential Mechanisms, and New Innovative Treatment Options. Pharmacol Rev 2020; 72:606-638. [PMID: 32540959 PMCID: PMC7300324 DOI: 10.1124/pr.120.019539] [Citation(s) in RCA: 321] [Impact Index Per Article: 80.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Epilepsy is a chronic neurologic disorder that affects over 70 million people worldwide. Despite the availability of over 20 antiseizure drugs (ASDs) for symptomatic treatment of epileptic seizures, about one-third of patients with epilepsy have seizures refractory to pharmacotherapy. Patients with such drug-resistant epilepsy (DRE) have increased risks of premature death, injuries, psychosocial dysfunction, and a reduced quality of life, so development of more effective therapies is an urgent clinical need. However, the various types of epilepsy and seizures and the complex temporal patterns of refractoriness complicate the issue. Furthermore, the underlying mechanisms of DRE are not fully understood, though recent work has begun to shape our understanding more clearly. Experimental models of DRE offer opportunities to discover, characterize, and challenge putative mechanisms of drug resistance. Furthermore, such preclinical models are important in developing therapies that may overcome drug resistance. Here, we will review the current understanding of the molecular, genetic, and structural mechanisms of ASD resistance and discuss how to overcome this problem. Encouragingly, better elucidation of the pathophysiological mechanisms underpinning epilepsies and drug resistance by concerted preclinical and clinical efforts have recently enabled a revised approach to the development of more promising therapies, including numerous potential etiology-specific drugs (“precision medicine”) for severe pediatric (monogenetic) epilepsies and novel multitargeted ASDs for acquired partial epilepsies, suggesting that the long hoped-for breakthrough in therapy for as-yet ASD-resistant patients is a feasible goal.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany (W.L.); Center for Systems Neuroscience, Hannover, Germany (W.L.); Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany (H.P.); Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom (S.S); and Department of Neuroscience, Mario Negri Institute for Pharmacological Research Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy (A.V.)
| | - Heidrun Potschka
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany (W.L.); Center for Systems Neuroscience, Hannover, Germany (W.L.); Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany (H.P.); Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom (S.S); and Department of Neuroscience, Mario Negri Institute for Pharmacological Research Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy (A.V.)
| | - Sanjay M Sisodiya
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany (W.L.); Center for Systems Neuroscience, Hannover, Germany (W.L.); Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany (H.P.); Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom (S.S); and Department of Neuroscience, Mario Negri Institute for Pharmacological Research Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy (A.V.)
| | - Annamaria Vezzani
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany (W.L.); Center for Systems Neuroscience, Hannover, Germany (W.L.); Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilians-University, Munich, Germany (H.P.); Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom (S.S); and Department of Neuroscience, Mario Negri Institute for Pharmacological Research Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy (A.V.)
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11
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Toyohara J, Sakata M, Tago T, Colabufo NA, Luurtsema G. Automated synthesis, preclinical toxicity, and radiation dosimetry of [ 18F]MC225 for clinical use: a tracer for measuring P-glycoprotein function at the blood-brain barrier. EJNMMI Res 2020; 10:84. [PMID: 32700099 PMCID: PMC7376787 DOI: 10.1186/s13550-020-00674-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/14/2020] [Indexed: 12/27/2022] Open
Abstract
INTRODUCTION [18F]MC225 is a selective substrate for P-glycoprotein (P-gp) that has good metabolic stability and shows higher baseline uptake compared with other P-gp substrates such as (R)-[11C]Verapamil. Prior to clinical translation, it is necessary to perform process validation of the radiosynthesis, assessment of preclinical toxicity, and radiation dosimetry. METHODS The production of [18F]MC225 was automated on a CFN-MPS200 multipurpose synthesizer. The acute toxicity of MC225 was evaluated at a dose of 2.5 mg/kg bodyweight, which is more than 10,000-fold the postulated maximum clinical dose of [18F]MC225. The acute toxicity of [18F]MC225 injection at a 200-fold dose, to administer a postulated dose of 185 MBq of [18F]MC225, was also evaluated after the decay-out of 18F. The mutagenicity of MC225 was studied by a reverse mutation test using Salmonella typhimurium and Escherichia coli (Ames test). In vivo biodistribution and dosimetry studies of [18F]MC225 were carried out in normal mice. Human dosimetry was estimated using OLINDA software. RESULTS The mean decay-corrected yields of [18F]MC225 at end of synthesis were 13%, with > 99% radiochemical purity, > 1000 GBq/μmol molar activity, and ≤ 1.5 μg/185 MBq of total chemical contents. All process validation batches complied with the product specifications and the process was confirmed to be appropriate for the production of [18F]MC225. No acute toxicity of MC225 or [18F]MC225 injection was found. No mutagenic activity was observed for MC225. The biodistribution study demonstrated both hepatobiliary and renal excretion of radioactivity. The most critical organ was the pancreas, with (63.8 μGy/MBq) or without urination (63.9 μGy/MBq) at 360 min after injection. The estimated effective dose (μSv/MBq) with and without urination at 360 min after injection was calculated as 15.7 and 16.9, respectively. CONCLUSION [18F]MC225 shows acceptable pharmacological safety at the dose required for adequate PET imaging. The potential risk associated with [18F]MC225 PET imaging is well within acceptable dose limits.
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Affiliation(s)
- Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Muneyuki Sakata
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Tetsuro Tago
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Nicola A. Colabufo
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - Gert Luurtsema
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen and University Medical Centre Groningen, Groningen, The Netherlands
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12
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Ilyas-Feldmann M, Asselin MC, Wang S, McMahon A, Anton-Rodriguez J, Brown G, Hinz R, Duncan JS, Sisodiya SM, Koepp M. P-glycoprotein overactivity in epileptogenic developmental lesions measured in vivo using (R)-[ 11 C]verapamil PET. Epilepsia 2020; 61:1472-1480. [PMID: 32627849 DOI: 10.1111/epi.16581] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 05/21/2020] [Accepted: 05/26/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Overexpression of the drug transporter P-glycoprotein (P-gp) is thought to be involved in drug-resistance in epilepsy by extrusion of antiepileptic drugs (AEDs). We used positron emission tomography (PET) and the P-gp substrate radiotracer (R)-[11 C]verapamil (VPM) together with the third-generation P-gp inhibitor tariquidar (TQD) to evaluate P-gp function in individuals with drug-resistant epileptogenic developmental lesions. METHODS Twelve healthy controls (7 male, median age 45, range 35-55 years), and two patients with epileptogenic developmental lesions (2 male, aged 24 and 62 years) underwent VPM-PET scans before and 60 minutes after a 30-minute infusion of 2 and 3 mg/kg TQD. The influx rate constant, VPM-K1 , was estimated from the first 10 minutes of dynamic data using a single-tissue compartment model with a VPM plasma input function. Statistical parametric mapping (SPM) analysis was used to compare individual patients with the healthy controls. RESULTS At baseline, SPM voxel-based analysis revealed significantly lower uptake of VPM corresponding to the area of the epileptogenic developmental lesion compared to 12 healthy controls (P < .048). This was accentuated following P-gp inhibition with TQD. After TQD, the uptake of VPM was significantly lower in the area of the epileptogenic developmental lesion compared to controls (P < .002). SIGNIFICANCE This study provides further evidence of P-gp overactivity in patients with drug-resistant epilepsy, irrespective of the type of lesion. Identifying P-gp overactivity as an underlying contributor to drug-resistance in individual patients will enable novel treatment strategies aimed at overcoming or reversing P-gp overactivity.
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Affiliation(s)
- Maria Ilyas-Feldmann
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Bucks, UK.,Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK.,Department of Neurology, Epilepsy-Center Berlin-Brandenburg, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Shaonan Wang
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK.,Global Pharmacometrics, Boehringer Ingelheim, Ingelheim am Rhein, Germany
| | - Adam McMahon
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
| | | | - Gavin Brown
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
| | - Rainer Hinz
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Bucks, UK
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Bucks, UK
| | - Matthias Koepp
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Bucks, UK
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13
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Löscher W. Epilepsy and Alterations of the Blood-Brain Barrier: Cause or Consequence of Epileptic Seizures or Both? Handb Exp Pharmacol 2020; 273:331-350. [PMID: 33136189 DOI: 10.1007/164_2020_406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The blood-brain barrier (BBB) is a dynamic, highly selective barrier primarily formed by endothelial cells connected by tight junctions that separate the circulating blood from the brain extracellular fluid, thereby preserving a narrow and stable homeostatic control of the neuronal environment. The endothelial cells lining the brain microvessels are under the inductive influence of neighboring cell types within the "neurovascular unit" including astrocytes and pericytes. In addition to the morphological characteristics of the BBB, various specific transport systems, enzymes, and receptors regulate the molecular and cellular traffic across the barrier. Furthermore, the intact BBB prevents many macromolecules and immune cells from entering the brain. This changes dramatically following epileptogenic brain insults; such insults, among other BBB alterations, lead to albumin extravasation and diapedesis of leukocytes from blood into brain parenchyma, inducing or contributing to epileptogenesis, which finally leads to development of spontaneous recurrent seizures and epilepsy. Furthermore, seizures themselves may cause BBB disruption with albumin extravasation, which has been shown to be associated with activation of astrocytes, activation of innate immune systems, and modifications of neuronal networks. However, seizure-induced BBB disruption is not necessarily associated with enhanced drug penetration into the brain, because the BBB expression of multidrug efflux transporters such as P-glycoprotein increases, most likely as a "second line defense" mechanism to protect the brain from drug toxicity. Hopefully, a better understanding of the complex BBB alterations in response to seizures and epilepsy can lead to novel therapeutic intervention to prevent epileptogenesis and the development of other detrimental sequelae of brain injury.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany.
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14
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Xu C, Wang Y, Zhang S, Nao J, Liu Y, Wang Y, Ding F, Zhong K, Chen L, Ying X, Wang S, Zhou Y, Duan S, Chen Z. Subicular pyramidal neurons gate drug resistance in temporal lobe epilepsy. Ann Neurol 2019; 86:626-640. [PMID: 31340057 DOI: 10.1002/ana.25554] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 07/17/2019] [Accepted: 07/18/2019] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Drug-resistant epilepsy causes great clinical danger and still lacks effective treatments. METHODS Here, we used multifaceted approaches combining electrophysiology, optogenetics, and chemogenetics in a classic phenytoin-resistant epilepsy model to reveal the key target of subicular pyramidal neurons in phenytoin resistance. RESULTS In vivo neural recording showed that the firing rate of pyramidal neurons in the subiculum, but not other hippocampal subregions, could not be inhibited by phenytoin in phenytoin-resistant rats. Selective inhibition of subicular pyramidal neurons by optogenetics or chemogenetics reversed phenytoin resistance, whereas selective activation of subicular pyramidal neurons induced phenytoin resistance. Moreover, long-term low-frequency stimulation at the subiculum, which is clinically feasible, significantly inhibited the subicular pyramidal neurons and reversed phenytoin resistance. Furthermore, in vitro electrophysiology revealed that off-target use of phenytoin on sodium channels of subicular pyramidal neurons was involved in the phenytoin resistance, and clinical neuroimaging data suggested the volume of the subiculum in drug-resistant patients was related to the usage of sodium channel inhibitors. INTERPRETATION These results highlight that the subicular pyramidal neurons may be a key switch control of drug-resistant epilepsy and represent a new potential target for precise treatments. ANN NEUROL 2019;86:626-640.
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Affiliation(s)
- Cenglin Xu
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yi Wang
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shuo Zhang
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jiazhen Nao
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yao Liu
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ying Wang
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Fang Ding
- Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kai Zhong
- School of Basic Medical Sciences & Forensic Medicine, Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Liying Chen
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoying Ying
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shuang Wang
- Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yudong Zhou
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shumin Duan
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhong Chen
- Institute of Pharmacology and Toxicology, Key Laboratory of Medical Neurobiology of National Health Commission and Chinese Academy of Medical Sciences, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China.,Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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15
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The predictive value of hypometabolism in focal epilepsy: a prospective study in surgical candidates. Eur J Nucl Med Mol Imaging 2019; 46:1806-1816. [PMID: 31144060 DOI: 10.1007/s00259-019-04356-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 05/01/2019] [Indexed: 12/19/2022]
Abstract
PURPOSE FDG PET is an established tool in presurgical epilepsy evaluation, but it is most often used selectively in patients with discordant MRI and EEG results. Interpretation is complicated by the presence of remote or multiple areas of hypometabolism, which leads to doubt as to the true location of the seizure onset zone (SOZ) and might have implications for predicting the surgical outcome. In the current study, we determined the sensitivity and specificity of PET localization prospectively in a consecutive unselected cohort of patients with focal epilepsy undergoing in-depth presurgical evaluation. METHODS A total of 130 patients who underwent PET imaging between 2006 and 2015 matched our inclusion criteria, and of these, 86 were operated on (72% with a favourable surgical outcome, Engel class I). Areas of focal hypometabolism were identified using statistical parametric mapping and concordance with MRI, EEG and intracranial EEG was evaluated. In the surgically treated patients, postsurgical outcome was used as the gold standard for correctness of localization (minimum follow-up 12 months). RESULTS PET sensitivity and specificity were both 95% in 86 patients with temporal lobe epilepsy (TLE) and 80% and 95%, respectively, in 44 patients with extratemporal epilepsy (ETLE). Significant extratemporal hypometabolism was observed in 17 TLE patients (20%). Temporal hypometabolism was observed in eight ETLE patients (18%). Among the 86 surgically treated patients, 26 (30%) had hypometabolism extending beyond the SOZ. The presence of unilobar hypometabolism, included in the resection, was predictive of complete seizure control (p = 0.007), with an odds ratio of 5.4. CONCLUSION Additional hypometabolic areas were found in one of five of this group of nonselected patients with focal epilepsy, including patients with "simple" lesional epilepsy, and this finding should prompt further in-depth evaluation of the correlation between EEG findings, semiology and PET. Hypometabolism confined to the epileptogenic zone as defined by EEG and MRI is associated with a favourable postoperative outcome in both TLE and ETLE patients.
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16
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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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17
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De Lange E, vd Berg D, Bellanti F, Voskuyl R, Syvänen S. P-glycoprotein protein expression versus functionality at the blood-brain barrier using immunohistochemistry, microdialysis and mathematical modeling. Eur J Pharm Sci 2018; 124:61-70. [DOI: 10.1016/j.ejps.2018.08.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 08/14/2018] [Accepted: 08/15/2018] [Indexed: 10/28/2022]
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18
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In Vitro Assessment of the Effect of Antiepileptic Drugs on Expression and Function of ABC Transporters and Their Interactions with ABCC2. Molecules 2017; 22:molecules22101484. [PMID: 28961159 PMCID: PMC6151573 DOI: 10.3390/molecules22101484] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 09/03/2017] [Indexed: 01/16/2023] Open
Abstract
ABC transporters have a significant role in drug disposition and response and various studies have implicated their involvement in epilepsy pharmacoresistance. Since genetic studies till now are inconclusive, we thought of investigating the role of xenobiotics as transcriptional modulators of ABC transporters. Here, we investigated the effect of six antiepileptic drugs (AEDs) viz. phenytoin, carbamazepine, valproate, lamotrigine, topiramate and levetiracetam, on the expression and function of ABCB1, ABCC1, ABCC2 and ABCG2 in Caco2 and HepG2 cell lines through real time PCR, western blot and functional activity assays. Further, the interaction of AEDs with maximally induced ABCC2 was studied. Carbamazepine caused a significant induction in expression of ABCB1 and ABCC2 in HepG2 and Caco2 cells, both at the transcript and protein level, together with increased functional activity. Valproate caused a significant increase in the expression and functional activity of ABCB1 in HepG2 only. No significant effect of phenytoin, lamotrigine, topiramate and levetiracetam on the transporters under study was observed in either of the cell lines. We demonstrated the interaction of carbamazepine and valproate with ABCC2 with ATPase and 5,6-carboxyfluorescein inhibition assays. Thus, altered functionality of ABCB1 and ABCC2 can affect the disposition and bioavailability of administered drugs, interfering with AED therapy.
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19
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Tang F, Hartz AMS, Bauer B. Drug-Resistant Epilepsy: Multiple Hypotheses, Few Answers. Front Neurol 2017; 8:301. [PMID: 28729850 PMCID: PMC5498483 DOI: 10.3389/fneur.2017.00301] [Citation(s) in RCA: 269] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 06/12/2017] [Indexed: 01/16/2023] Open
Abstract
Epilepsy is a common neurological disorder that affects over 70 million people worldwide. Despite the recent introduction of new antiseizure drugs (ASDs), about one-third of patients with epilepsy have seizures refractory to pharmacotherapy. Early identification of patients who will become refractory to ASDs could help direct such patients to appropriate non-pharmacological treatment, but the complexity in the temporal patterns of epilepsy could make such identification difficult. The target hypothesis and transporter hypothesis are the most cited theories trying to explain refractory epilepsy, but neither theory alone fully explains the neurobiological basis of pharmacoresistance. This review summarizes evidence for and against several major theories, including the pharmacokinetic hypothesis, neural network hypothesis, intrinsic severity hypothesis, gene variant hypothesis, target hypothesis, and transporter hypothesis. The discussion is mainly focused on the transporter hypothesis, where clinical and experimental data are discussed on multidrug transporter overexpression, substrate profiles of ASDs, mechanism of transporter upregulation, polymorphisms of transporters, and the use of transporter inhibitors. Finally, future perspectives are presented for the improvement of current hypotheses and the development of treatment strategies as guided by the current understanding of refractory epilepsy.
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Affiliation(s)
- Fei Tang
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, United States
| | - Anika M S Hartz
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States.,Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Björn Bauer
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, United States.,Epilepsy Center, University of Kentucky, Lexington, KY, United States
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Han H, Mann A, Ekstein D, Eyal S. Breaking Bad: the Structure and Function of the Blood-Brain Barrier in Epilepsy. AAPS JOURNAL 2017; 19:973-988. [DOI: 10.1208/s12248-017-0096-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 04/28/2017] [Indexed: 12/27/2022]
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Hartz AMS, Pekcec A, Soldner ELB, Zhong Y, Schlichtiger J, Bauer B. P-gp Protein Expression and Transport Activity in Rodent Seizure Models and Human Epilepsy. Mol Pharm 2017; 14:999-1011. [PMID: 28195743 DOI: 10.1021/acs.molpharmaceut.6b00770] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A cure for epilepsy is currently not available, and seizure genesis, seizure recurrence, and resistance to antiseizure drugs remain serious clinical problems. Studies show that the blood-brain barrier is altered in animal models of epilepsy and in epileptic patients. In this regard, seizures increase expression of blood-brain barrier efflux transporters such as P-glycoprotein (P-gp), which is thought to reduce brain uptake of antiseizure drugs, and thus, contribute to antiseizure drug resistance. The goal of the current study was to assess the viability of combining in vivo and ex vivo preparations of isolated brain capillaries from animal models of seizures and epilepsy as well as from patients with epilepsy to study P-gp at the blood-brain barrier. Exposing isolated rat brain capillaries to glutamate ex vivo upregulated P-gp expression to levels that were similar to those in capillaries isolated from rats that had status epilepticus or chronic epilepsy. Moreover, the fold-increase in P-gp protein expression seen in animal models is consistent with the fold-increase in P-gp observed in human brain capillaries isolated from patients with epilepsy compared to age-matched control individuals. Overall, the in vivo/ex vivo approach presented here allows detailed analysis of the mechanisms underlying seizure-induced changes of P-gp expression and transport activity at the blood-brain barrier. This approach can be extended to other blood-brain barrier proteins that might contribute to drug-resistant epilepsy or other CNS disorders as well.
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Affiliation(s)
- Anika M S Hartz
- Sanders-Brown Center on Aging, University of Kentucky , Lexington, Kentucky 40536, United States.,Department of Pharmacology and Nutritional Sciences, University of Kentucky , Lexington, Kentucky 40536, United States
| | - Anton Pekcec
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota , Duluth, Minnesota 55812, United States
| | - Emma L B Soldner
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota , Duluth, Minnesota 55812, United States
| | - Yu Zhong
- Sanders-Brown Center on Aging, University of Kentucky , Lexington, Kentucky 40536, United States
| | - Juli Schlichtiger
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota , Duluth, Minnesota 55812, United States
| | - Bjoern Bauer
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky , Lexington, Kentucky 40536, United States.,Epilepsy Center, University of Kentucky , Lexington, Kentucky 40536, United States
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23
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Abstract
Positron emission tomography (PET) is a neuroimaging method that offers insights into the molecular functioning of a human brain. It has been widely used to study metabolic and neurotransmitter abnormalities in people with epilepsy. This article reviews the development of several PET radioligands and their application in studying the molecular mechanisms of epilepsy. Over the last decade, tracers binding to serotonin and γ-aminobutyric acid (GABA) receptors have been used to delineate the location of the epileptic focus. PET studies have examined the role of opioids, cannabinoids, acetylcholine, and dopamine in modulating neuronal hyperexcitability and seizure termination. In vivo analyses of drug transporters, e.g., P-glycoprotein, have increased our understanding of pharmacoresistance that could inform new therapeutic strategies. Finally, PET experiments targeting neuroinflammation and glutamate receptors might guide the development of novel biomarkers of epileptogenesis.
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Affiliation(s)
- Marian Galovic
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, 33 Queen Square, London, WC1N 3BG, United Kingdom.,Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - Matthias Koepp
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, 33 Queen Square, London, WC1N 3BG, United Kingdom. .,Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom.
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24
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Brzozowska N, Li KM, Wang XS, Booth J, Stuart J, McGregor IS, Arnold JC. ABC transporters P-gp and Bcrp do not limit the brain uptake of the novel antipsychotic and anticonvulsant drug cannabidiol in mice. PeerJ 2016; 4:e2081. [PMID: 27257556 PMCID: PMC4888295 DOI: 10.7717/peerj.2081] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/03/2016] [Indexed: 12/14/2022] Open
Abstract
Cannabidiol (CBD) is currently being investigated as a novel therapeutic for the treatment of CNS disorders like schizophrenia and epilepsy. ABC transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) mediate pharmacoresistance in these disorders. P-gp and Bcrp are expressed at the blood brain barrier (BBB) and reduce the brain uptake of substrate drugs including various antipsychotics and anticonvulsants. It is therefore important to assess whether CBD is prone to treatment resistance mediated by P-gp and Bcrp. Moreover, it has become common practice in the drug development of CNS agents to screen against ABC transporters to help isolate lead compounds with optimal pharmacokinetic properties. The current study aimed to assess whether P-gp and Bcrp impacts the brain transport of CBD by comparing CBD tissue concentrations in wild-type (WT) mice versus mice devoid of ABC transporter genes. P-gp knockout (Abcb1a/b (-∕-)), Bcrp knockout (Abcg2 (-∕-)), combined P-gp/Bcrp knockout (Abcb1a/b (-∕-) Abcg2 (-∕-)) and WT mice were injected with CBD, before brain and plasma samples were collected at various time-points. CBD results were compared with the positive control risperidone and 9-hydroxy risperidone, antipsychotic drugs that are established ABC transporter substrates. Brain and plasma concentrations of CBD were not greater in P-gp, Bcrp or P-gp/Bcrp knockout mice than WT mice. In comparison, the brain/plasma concentration ratios of risperidone and 9-hydroxy risperidone were profoundly higher in P-gp knockout mice than WT mice. These results suggest that CBD is not a substrate of P-gp or Bcrp and may be free from the complication of reduced brain uptake by these transporters. Such findings provide favorable evidence for the therapeutic development of CBD in the treatment of various CNS disorders.
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Affiliation(s)
- Natalia Brzozowska
- Discipline of Pharmacology, School of Medical Science, University of Sydney , Sydney, NSW , Australia
| | - Kong M Li
- Discipline of Pharmacology, School of Medical Science, University of Sydney , Sydney, NSW , Australia
| | - Xiao Suo Wang
- Bosch Mass Spectrometry Facility, Bosch Institute, Sydney Medical School, University of Sydney , Sydney, NSW , Australia
| | - Jessica Booth
- Psychopharmacology Laboratory, School of Psychology, Faculty of Science, University of Sydney , Sydney, NSW , Australia
| | - Jordyn Stuart
- The Lambert Initiative of Cannabinoid Therapeutics, The Brain and Mind Centre, University of Sydney, Sydney, NSW, Australia; Psychopharmacology Laboratory, School of Psychology, Faculty of Science, University of Sydney, Sydney, NSW, Australia
| | - Iain S McGregor
- The Lambert Initiative of Cannabinoid Therapeutics, The Brain and Mind Centre, University of Sydney, Sydney, NSW, Australia; Psychopharmacology Laboratory, School of Psychology, Faculty of Science, University of Sydney, Sydney, NSW, Australia
| | - Jonathon C Arnold
- Discipline of Pharmacology, School of Medical Science, University of Sydney, Sydney, NSW, Australia; The Lambert Initiative of Cannabinoid Therapeutics, The Brain and Mind Centre, University of Sydney, Sydney, NSW, Australia
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Toyohara J, Okamoto M, Aramaki H, Zaitsu Y, Shimizu I, Ishiwata K. ( R )-[ 11 C]Emopamil as a novel tracer for imaging enhanced P-glycoprotein function. Nucl Med Biol 2016; 43:52-62. [DOI: 10.1016/j.nucmedbio.2015.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 08/31/2015] [Accepted: 09/03/2015] [Indexed: 11/28/2022]
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Abstract
Imaging is pivotal in the evaluation and management of patients with seizure disorders. Elegant structural neuroimaging with magnetic resonance imaging (MRI) may assist in determining the etiology of focal epilepsy and demonstrating the anatomical changes associated with seizure activity. The high diagnostic yield of MRI to identify the common pathological findings in individuals with focal seizures including mesial temporal sclerosis, vascular anomalies, low-grade glial neoplasms and malformations of cortical development has been demonstrated. Positron emission tomography (PET) is the most commonly performed interictal functional neuroimaging technique that may reveal a focal hypometabolic region concordant with seizure onset. Single photon emission computed tomography (SPECT) studies may assist performance of ictal neuroimaging in patients with pharmacoresistant focal epilepsy being considered for neurosurgical treatment. This chapter highlights neuroimaging developments and innovations, and provides a comprehensive overview of the imaging strategies used to improve the care and management of people with epilepsy.
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Nicita F, Spalice A, Raucci U, Iannetti P, Parisi P. The possible use of the L-type calcium channel antagonist verapamil in drug-resistant epilepsy. Expert Rev Neurother 2015; 16:9-15. [PMID: 26567612 DOI: 10.1586/14737175.2016.1121097] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Multidrug transporters (MDTs) are likely to play a role in the pathogenesis of drug resistance in epilepsy, acting at the level of the blood-brain barrier by returning antiepileptic drugs to the blood vessels and lowering brain penetration and concentration (e.g. the so-called multidrug transporter hypothesis). In the last ten years experimental studies on both animal models and human brain tissues have highlighted a potential role of the P-glycoprotein-one of the multidrug transporters of the blood-brain barrier-in the pathophysiology of drug-resistant epilepsies. At the same time, verapamil has been administered to patients with drug-resistant epilepsy (e.g., Dravet syndrome, Lennox-Gastaut syndrome, focal epilepsies) or status epilepticus with promising results. In this drug profile paper the authors review current knowledge and main published studies regarding the role of the L-type calcium channel antagonist verapamil in drug-resistant epilepsy.
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Affiliation(s)
- Francesco Nicita
- a Department of Pediatrics, Child Neurology Division , Sapienza University of Rome , Rome , Italy
| | - Alberto Spalice
- a Department of Pediatrics, Child Neurology Division , Sapienza University of Rome , Rome , Italy
| | - Umberto Raucci
- b Emergency Pediatric Department , "Bambino Gesù" Children's Hospital, IRCCS , Rome , Italy
| | - Paola Iannetti
- a Department of Pediatrics, Child Neurology Division , Sapienza University of Rome , Rome , Italy
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Research Progress on the Role of ABC Transporters in the Drug Resistance Mechanism of Intractable Epilepsy. BIOMED RESEARCH INTERNATIONAL 2015; 2015:194541. [PMID: 26491660 PMCID: PMC4600483 DOI: 10.1155/2015/194541] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 12/17/2022]
Abstract
The pathogenesis of intractable epilepsy is not fully clear. In recent years, both animal and clinical trials have shown that the expression of ATP-binding cassette (ABC) transporters is increased in patients with intractable epilepsy; additionally, epileptic seizures can lead to an increase in the number of sites that express ABC transporters. These findings suggest that ABC transporters play an important role in the drug resistance mechanism of epilepsy. ABC transporters can perform the funcions of a drug efflux pump, which can reduce the effective drug concentration at epilepsy lesions by reducing the permeability of the blood brain barrier to antiepileptic drugs, thus causing resistance to antiepileptic drugs. Given the important role of ABC transporters in refractory epilepsy drug resistance, antiepileptic drugs that are not substrates of ABC transporters were used to obtain ABC transporter inhibitors with strong specificity, high safety, and few side effects, making them suitable for long-term use; therefore, these drugs can be used for future clinical treatment of intractable epilepsy.
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Liu L, Collier AC, Link JM, Domino KB, Mankoff DA, Eary JF, Spiekerman CF, Hsiao P, Deo AK, Unadkat JD. Modulation of P-glycoprotein at the Human Blood-Brain Barrier by Quinidine or Rifampin Treatment: A Positron Emission Tomography Imaging Study. Drug Metab Dispos 2015; 43:1795-804. [PMID: 26354948 DOI: 10.1124/dmd.114.058685] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 09/01/2015] [Indexed: 11/22/2022] Open
Abstract
Permeability-glycoprotein (P-glycoprotein, P-gp), an efflux transporter at the human blood-brain barrier (BBB), is a significant obstacle to central nervous system (CNS) delivery of P-gp substrate drugs. Using positron emission tomography imaging, we investigated P-gp modulation at the human BBB by an approved P-gp inhibitor, quinidine, or the P-gp inducer, rifampin. Cerebral blood flow (CBF) and BBB P-gp activity were respectively measured by administration of (15)O-water followed by (11)C-verapamil. In a crossover design, healthy volunteers received quinidine and 11-29 days of rifampin treatment during different study periods. CBF and P-gp activity was measured in the absence (control; prior to quinidine treatment) and presence of P-gp modulation. At clinically relevant quinidine plasma concentrations, P-gp inhibition resulted in a 60% increase in (11)C-radioactivity distribution across the human BBB as measured by the brain extraction ratio (ER) of (11)C-radioactivity. Furthermore, the magnitude of BBB P-gp inhibition by quinidine was successfully predicted by a combination of in vitro and macaque data, but not by rat data. Although our findings demonstrated that quinidine did not completely inhibit P-gp at the human BBB, it has the potential to produce clinically significant CNS drug interactions with P-gp substrate drugs that exhibit a narrow therapeutic window and are significantly excluded from the brain by P-gp. Rifampin treatment induced systemic CYP3A metabolism of (11)C-verapamil; however, it reduced the ER by 6%. Therefore, we conclude that rifampin, at its usual clinical dose, cannot be used to induce P-gp at the human BBB to a clinically meaningful extent and is unlikely to cause inadvertent BBB-inductive drug interactions.
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Affiliation(s)
- Li Liu
- Department of Pharmaceutics (L.L., P.H., A.K.D., J.D.U.), Department of Medicine (A.C.C.), Division of Nuclear Medicine (J.M.L., D.A.M., J.F.E.), Department of Anesthesiology and Pain Medicine (K.B.D.), and Department of Oral Health Sciences (C.F.S.), University of Washington, Seattle, Washington
| | - Ann C Collier
- Department of Pharmaceutics (L.L., P.H., A.K.D., J.D.U.), Department of Medicine (A.C.C.), Division of Nuclear Medicine (J.M.L., D.A.M., J.F.E.), Department of Anesthesiology and Pain Medicine (K.B.D.), and Department of Oral Health Sciences (C.F.S.), University of Washington, Seattle, Washington
| | - Jeanne M Link
- Department of Pharmaceutics (L.L., P.H., A.K.D., J.D.U.), Department of Medicine (A.C.C.), Division of Nuclear Medicine (J.M.L., D.A.M., J.F.E.), Department of Anesthesiology and Pain Medicine (K.B.D.), and Department of Oral Health Sciences (C.F.S.), University of Washington, Seattle, Washington
| | - Karen B Domino
- Department of Pharmaceutics (L.L., P.H., A.K.D., J.D.U.), Department of Medicine (A.C.C.), Division of Nuclear Medicine (J.M.L., D.A.M., J.F.E.), Department of Anesthesiology and Pain Medicine (K.B.D.), and Department of Oral Health Sciences (C.F.S.), University of Washington, Seattle, Washington
| | - David A Mankoff
- Department of Pharmaceutics (L.L., P.H., A.K.D., J.D.U.), Department of Medicine (A.C.C.), Division of Nuclear Medicine (J.M.L., D.A.M., J.F.E.), Department of Anesthesiology and Pain Medicine (K.B.D.), and Department of Oral Health Sciences (C.F.S.), University of Washington, Seattle, Washington
| | - Janet F Eary
- Department of Pharmaceutics (L.L., P.H., A.K.D., J.D.U.), Department of Medicine (A.C.C.), Division of Nuclear Medicine (J.M.L., D.A.M., J.F.E.), Department of Anesthesiology and Pain Medicine (K.B.D.), and Department of Oral Health Sciences (C.F.S.), University of Washington, Seattle, Washington
| | - Charles F Spiekerman
- Department of Pharmaceutics (L.L., P.H., A.K.D., J.D.U.), Department of Medicine (A.C.C.), Division of Nuclear Medicine (J.M.L., D.A.M., J.F.E.), Department of Anesthesiology and Pain Medicine (K.B.D.), and Department of Oral Health Sciences (C.F.S.), University of Washington, Seattle, Washington
| | - Peng Hsiao
- Department of Pharmaceutics (L.L., P.H., A.K.D., J.D.U.), Department of Medicine (A.C.C.), Division of Nuclear Medicine (J.M.L., D.A.M., J.F.E.), Department of Anesthesiology and Pain Medicine (K.B.D.), and Department of Oral Health Sciences (C.F.S.), University of Washington, Seattle, Washington
| | - Anand K Deo
- Department of Pharmaceutics (L.L., P.H., A.K.D., J.D.U.), Department of Medicine (A.C.C.), Division of Nuclear Medicine (J.M.L., D.A.M., J.F.E.), Department of Anesthesiology and Pain Medicine (K.B.D.), and Department of Oral Health Sciences (C.F.S.), University of Washington, Seattle, Washington
| | - Jashvant D Unadkat
- Department of Pharmaceutics (L.L., P.H., A.K.D., J.D.U.), Department of Medicine (A.C.C.), Division of Nuclear Medicine (J.M.L., D.A.M., J.F.E.), Department of Anesthesiology and Pain Medicine (K.B.D.), and Department of Oral Health Sciences (C.F.S.), University of Washington, Seattle, Washington
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Abstract
Epilepsy is a serious neurological disorder that affects more than 60 million people worldwide. Intractable epilepsy (IE) refers to approximately 20%-30% of epileptic patients who fail to achieve seizure control with antiepileptic drug (AED) treatment. Although the mechanisms underlying IE are not well understood, it has been hypothesized that multidrug transporters such as P-glycoprotein (P-gp) play a major role in drug efflux at the blood-brain barrier, and may be the underlying factor in the variable responses of patients to AEDs. The main goal of the present review is to show evidence from different areas that support the idea that the overexpression of P-gp is associated with IE. We discuss here evidence from animal studies, pharmacology, clinical cases and genetic studies.
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Affiliation(s)
- Guang-Xin Wang
- a Medical Institute of Paediatrics , Qilu Children's Hospital of Shandong University , Jinan , P.R. China
| | - Da-Wei Wang
- b Department of Biochemistry and Molecular Biology , School of Medicine, Shandong University , Jinan , P.R. China
| | - Yong Liu
- a Medical Institute of Paediatrics , Qilu Children's Hospital of Shandong University , Jinan , P.R. China
| | - Yan-Hui Ma
- a Medical Institute of Paediatrics , Qilu Children's Hospital of Shandong University , Jinan , P.R. China
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Fekete Z, Rajnai Z, Nagy T, Jakab KT, Kurunczi A, Gémes K, Herédi-Szabó K, Fülöp F, Tóth GK, Czerwinski M, Loewen G, Krajcsi P. Membrane Assays to Characterize Interaction of Drugs with ABCB1. J Membr Biol 2015; 248:967-77. [DOI: 10.1007/s00232-015-9804-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 04/20/2015] [Indexed: 11/29/2022]
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Bauer M. [MUV researcher of the month, March 2015]. Wien Klin Wochenschr 2015; 127:232-3. [PMID: 25794564 DOI: 10.1007/s00508-015-0778-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Martin Bauer
- Universitätsklinik für Klinische Pharmakologie, Medizinische Universität Wien, Währinger Gürtel 18-20, 1090, Wien, Österreich,
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