1
|
Potassium channelopathies associated with epilepsy-related syndromes and directions for therapeutic intervention. Biochem Pharmacol 2023; 208:115413. [PMID: 36646291 DOI: 10.1016/j.bcp.2023.115413] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
A number of mutations to members of several CNS potassium (K) channel families have been identified which result in rare forms of neonatal onset epilepsy, or syndromes of which one prominent characteristic is a form of epilepsy. Benign Familial Neonatal Convulsions or Seizures (BFNC or BFNS), also referred to as Self-Limited Familial Neonatal Epilepsy (SeLNE), results from mutations in 2 members of the KV7 family (KCNQ) of K channels; while generally self-resolving by about 15 weeks of age, these mutations significantly increase the probability of generalized seizure disorders in the adult, in some cases they result in more severe developmental syndromes. Epilepsy of Infancy with Migrating Focal Seizures (EIMSF), or Migrating Partial Seizures of Infancy (MMPSI), is a rare severe form of epilepsy linked primarily to gain of function mutations in a member of the sodium-dependent K channel family, KCNT1 or SLACK. Finally, KCNMA1 channelopathies, including Liang-Wang syndrome (LIWAS), are rare combinations of neurological symptoms including seizure, movement abnormalities, delayed development and intellectual disabilities, with Liang-Wang syndrome an extremely serious polymalformative syndrome with a number of neurological sequelae including epilepsy. These are caused by mutations in the pore-forming subunit of the large-conductance calcium-activated K channel (BK channel) KCNMA1. The identification of these rare but significant channelopathies has resulted in a resurgence of interest in their treatment by direct pharmacological or genetic modulation. We will briefly review the genetics, biophysics and pharmacology of these K channels, their linkage with the 3 syndromes described above, and efforts to more effectively target these syndromes.
Collapse
|
2
|
Shegani A, Kealey S, Luzi F, Basagni F, Machado JDM, Ekici SD, Ferocino A, Gee AD, Bongarzone S. Radiosynthesis, Preclinical, and Clinical Positron Emission Tomography Studies of Carbon-11 Labeled Endogenous and Natural Exogenous Compounds. Chem Rev 2022; 123:105-229. [PMID: 36399832 PMCID: PMC9837829 DOI: 10.1021/acs.chemrev.2c00398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The presence of positron emission tomography (PET) centers at most major hospitals worldwide, along with the improvement of PET scanner sensitivity and the introduction of total body PET systems, has increased the interest in the PET tracer development using the short-lived radionuclides carbon-11. In the last few decades, methodological improvements and fully automated modules have allowed the development of carbon-11 tracers for clinical use. Radiolabeling natural compounds with carbon-11 by substituting one of the backbone carbons with the radionuclide has provided important information on the biochemistry of the authentic compounds and increased the understanding of their in vivo behavior in healthy and diseased states. The number of endogenous and natural compounds essential for human life is staggering, ranging from simple alcohols to vitamins and peptides. This review collates all the carbon-11 radiolabeled endogenous and natural exogenous compounds synthesised to date, including essential information on their radiochemistry methodologies and preclinical and clinical studies in healthy subjects.
Collapse
Affiliation(s)
- Antonio Shegani
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Steven Kealey
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Federico Luzi
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Filippo Basagni
- Department
of Pharmacy and Biotechnology, Alma Mater
Studiorum−University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | - Joana do Mar Machado
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Sevban Doğan Ekici
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Alessandra Ferocino
- Institute
of Organic Synthesis and Photoreactivity, Italian National Research Council, via Piero Gobetti 101, 40129 Bologna, Italy
| | - Antony D. Gee
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom,A.G.: email,
| | - Salvatore Bongarzone
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom,S.B.:
email,
| |
Collapse
|
3
|
Bajza Á, Kocsis D, Berezvai O, Laki AJ, Lukács B, Imre T, Iván K, Szabó P, Erdő F. Verification of P-Glycoprotein Function at the Dermal Barrier in Diffusion Cells and Dynamic "Skin-On-A-Chip" Microfluidic Device. Pharmaceutics 2020; 12:E804. [PMID: 32854319 PMCID: PMC7559210 DOI: 10.3390/pharmaceutics12090804] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 01/05/2023] Open
Abstract
The efficacy of transdermal absorption of drugs and the irritation or corrosion potential of topically applied formulations are important areas of investigation in pharmaceutical, military and cosmetic research. The aim of the present experiments is to test the role of P-glycoprotein in dermal drug delivery in various ex vivo and in vitro platforms, including a novel microchip technology developed by Pázmány Péter Catholic University. A further question is whether the freezing of excised skin and age have any influence on P-glycoprotein-mediated dermal drug absorption. Two P-glycoprotein substrate model drugs (quinidine and erythromycin) were investigated via topical administration in diffusion cells, a skin-on-a-chip device and transdermal microdialysis in rat skin. The transdermal absorption of both model drugs was reduced by P-glycoprotein inhibition, and both aging and freezing increased the permeability of the tissues. Based on our findings, it is concluded that the process of freezing leads to reduced function of efflux transporters, and increases the porosity of skin. P-glycoprotein has an absorptive orientation in the skin, and topical inhibitors can modify its action. The defensive role of the skin seems to be diminished in aged individuals, partly due to reduced thickness of the dermis. The novel microfluidic microchip seems to be an appropriate tool to investigate dermal drug delivery.
Collapse
Affiliation(s)
- Ágnes Bajza
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Práter u. 50a, H-1083 Budapest, Hungary; (Á.B.); (D.K.); (O.B.); (A.J.L.); (K.I.)
| | - Dorottya Kocsis
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Práter u. 50a, H-1083 Budapest, Hungary; (Á.B.); (D.K.); (O.B.); (A.J.L.); (K.I.)
| | - Orsolya Berezvai
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Práter u. 50a, H-1083 Budapest, Hungary; (Á.B.); (D.K.); (O.B.); (A.J.L.); (K.I.)
- Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | - András József Laki
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Práter u. 50a, H-1083 Budapest, Hungary; (Á.B.); (D.K.); (O.B.); (A.J.L.); (K.I.)
- Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó u. 37-47, H-1094 Budapest, Hungary
| | - Bence Lukács
- MedRes Medical Research Engineering Ltd., Albert Flórián út 3/b, H-1097 Budapest, Hungary; or
| | - Tímea Imre
- Research Centre for Natural Sciences, Instrumentation Centre, Magyar tudósok körútja 2, H-1117 Budapest, Hungary; (T.I.); (P.S.)
| | - Kristóf Iván
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Práter u. 50a, H-1083 Budapest, Hungary; (Á.B.); (D.K.); (O.B.); (A.J.L.); (K.I.)
| | - Pál Szabó
- Research Centre for Natural Sciences, Instrumentation Centre, Magyar tudósok körútja 2, H-1117 Budapest, Hungary; (T.I.); (P.S.)
| | - Franciska Erdő
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Práter u. 50a, H-1083 Budapest, Hungary; (Á.B.); (D.K.); (O.B.); (A.J.L.); (K.I.)
| |
Collapse
|
4
|
Neuroimaging Biomarkers of Experimental Epileptogenesis and Refractory Epilepsy. Int J Mol Sci 2019; 20:ijms20010220. [PMID: 30626103 PMCID: PMC6337422 DOI: 10.3390/ijms20010220] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 12/31/2018] [Accepted: 01/03/2019] [Indexed: 11/17/2022] Open
Abstract
This article provides an overview of neuroimaging biomarkers in experimental epileptogenesis and refractory epilepsy. Neuroimaging represents a gold standard and clinically translatable technique to identify neuropathological changes in epileptogenesis and longitudinally monitor its progression after a precipitating injury. Neuroimaging studies, along with molecular studies from animal models, have greatly improved our understanding of the neuropathology of epilepsy, such as the hallmark hippocampus sclerosis. Animal models are effective for differentiating the different stages of epileptogenesis. Neuroimaging in experimental epilepsy provides unique information about anatomic, functional, and metabolic alterations linked to epileptogenesis. Recently, several in vivo biomarkers for epileptogenesis have been investigated for characterizing neuronal loss, inflammation, blood-brain barrier alterations, changes in neurotransmitter density, neurovascular coupling, cerebral blood flow and volume, network connectivity, and metabolic activity in the brain. Magnetic resonance imaging (MRI) is a sensitive method for detecting structural and functional changes in the brain, especially to identify region-specific neuronal damage patterns in epilepsy. Positron emission tomography (PET) and single-photon emission computerized tomography are helpful to elucidate key functional alterations, especially in areas of brain metabolism and molecular patterns, and can help monitor pathology of epileptic disorders. Multimodal procedures such as PET-MRI integrated systems are desired for refractory epilepsy. Validated biomarkers are warranted for early identification of people at risk for epilepsy and monitoring of the progression of medical interventions.
Collapse
|
5
|
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]
|
6
|
Verbeek J, Eriksson J, Syvänen S, Huisman M, Schuit RC, Molthoff CFM, Voskuyl RA, de Lange EC, Lammertsma AA, Windhorst AD. Synthesis and preliminary preclinical evaluation of fluorine-18 labelled isatin-4-(4-methoxyphenyl)-3-thiosemicarbazone ([ 18F]4FIMPTC) as a novel PET tracer of P-glycoprotein expression. EJNMMI Radiopharm Chem 2018; 3:11. [PMID: 30294663 PMCID: PMC6150866 DOI: 10.1186/s41181-018-0046-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 07/18/2018] [Indexed: 01/16/2023] Open
Abstract
Background Several P-glycoprotein (P-gp) substrate tracers are available to assess P-gp function in vivo, but attempts to develop a tracer for measuring expression levels of P-gp have not been successful. Recently, (Z)-2-(5-fluoro-2-oxoindolin-3-ylidene)-N-(4-methoxyphenyl)hydrazine-carbothioamide was described as a potential selective P-gp inhibitor that is not transported by P-gp. Therefore, the purpose of this study was to radiolabel two of its analogues and to assess their potential for imaging P-gp expression using PET. Results [18F]2-(4-fluoro-2-oxoindolin-3-ylidene)-N-(4-methoxyphenyl)hydrazine-carbothioamide ([18F]5) and [18F]2-(6-fluoro-2-oxoindolin-3-ylidene)-N-(4-methoxyphenyl)hydrazine-carbothioamide ([18F]6) were synthesized and both their biodistribution and metabolism were evaluated in rats. In addition, PET scans were acquired in rats before and after tariquidar (P-gp inhibitor) administration as well as in P-gp knockout (KO) mice. Both [18F]5 and [18F]6 were synthesized in 2–3% overall yield, and showed high brain uptake in ex vivo biodistribution studies. [18F]6 appeared to be metabolically unstable in vivo, while [18F]5 showed moderate stability with limited uptake of radiolabelled metabolites in the brain. PET studies showed that transport of [18F]5 across the blood-brain barrier was not altered by pre-treatment with the P-gp inhibitor tariquidar, and uptake was significantly lower in P-gp KO than in wild-type animals and indeed transported across the BBB or bound to P-gp in endothelial cells. Conclusion In conclusion, [18F]5 and [18F]6 were successfully and reproducibly synthesized, albeit with low radiochemical yields. [18F]5 appears to be a radiotracer that binds to P-gp, as showed in P-gp knock-out animals, but is not a substrate for P-gp.
Collapse
Affiliation(s)
- Joost Verbeek
- 1Department of Radiology & Nuclear Medicine, VU University Medical Center, P.O. box 7057, 1007 MB Amsterdam, The Netherlands
| | - Jonas Eriksson
- 1Department of Radiology & Nuclear Medicine, VU University Medical Center, P.O. box 7057, 1007 MB Amsterdam, The Netherlands.,3Present Address: Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Stina Syvänen
- 2Division of Pharmacology, LACDR, Leiden University, Leiden, The Netherlands.,3Present Address: Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Marc Huisman
- 1Department of Radiology & Nuclear Medicine, VU University Medical Center, P.O. box 7057, 1007 MB Amsterdam, The Netherlands
| | - Robert C Schuit
- 1Department of Radiology & Nuclear Medicine, VU University Medical Center, P.O. box 7057, 1007 MB Amsterdam, The Netherlands
| | - Carla F M Molthoff
- 1Department of Radiology & Nuclear Medicine, VU University Medical Center, P.O. box 7057, 1007 MB Amsterdam, The Netherlands
| | - Rob A Voskuyl
- 2Division of Pharmacology, LACDR, Leiden University, Leiden, The Netherlands.,4Stichting Epilepsie Instellingen Nederland, SEIN, Heemstede, The Netherlands
| | | | - Adriaan A Lammertsma
- 1Department of Radiology & Nuclear Medicine, VU University Medical Center, P.O. box 7057, 1007 MB Amsterdam, The Netherlands
| | - Albert D Windhorst
- 1Department of Radiology & Nuclear Medicine, VU University Medical Center, P.O. box 7057, 1007 MB Amsterdam, The Netherlands
| |
Collapse
|
7
|
van Dijkman SC, Voskuyl RA, de Lange EC. Biomarkers in epilepsy-A modelling perspective. Eur J Pharm Sci 2017; 109S:S47-S52. [PMID: 28528284 DOI: 10.1016/j.ejps.2017.05.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 05/15/2017] [Indexed: 10/19/2022]
Abstract
Biomarkers can be categorised from type 0 (genotype or phenotype), through 6 (clinical scales), each level representing a part of the processes involved in the biological system and drug treatment. This classification facilitates the identification and connection of information required to fully (mathematically) model a disease and its treatment using integrated information from biomarkers. Two recent reviews thoroughly discussed the current status and development of biomarkers for epilepsy, but a path towards the integration of such biomarkers for the personalisation of anti-epileptic drug treatment is lacking. Here we aim to 1) briefly categorise the available epilepsy biomarkers and identify gaps, and 2) provide a modelling perspective on approaches to fill such gaps. There is mainly a lack of biomarker types 2 (target occupancy) and 3 (target activation). Current literature typically focuses on qualitative biomarkers for diagnosis and prediction of treatment response or failure, leaving a need for biomarkers that help to quantitatively understand the overall system to explain and predict differences in disease and treatment outcome. Due to the complexity of epilepsy, filling the biomarker gaps will require collaboration and expertise from the fields of systems biology and systems pharmacology.
Collapse
Affiliation(s)
- Sven C van Dijkman
- Division of Pharmacology, Leiden Academic Centre for Drug Research, The Netherlands.
| | - Rob A Voskuyl
- Division of Pharmacology, Leiden Academic Centre for Drug Research, The Netherlands
| | - Elizabeth C de Lange
- Division of Pharmacology, Leiden Academic Centre for Drug Research, The Netherlands
| |
Collapse
|
8
|
Neuroimaging in animal models of epilepsy. Neuroscience 2017; 358:277-299. [DOI: 10.1016/j.neuroscience.2017.06.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 02/06/2023]
|
9
|
Non-invasive PET imaging of brain inflammation at disease onset predicts spontaneous recurrent seizures and reflects comorbidities. Brain Behav Immun 2017; 61:69-79. [PMID: 28017648 DOI: 10.1016/j.bbi.2016.12.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/05/2016] [Accepted: 12/18/2016] [Indexed: 02/06/2023] Open
Abstract
Brain inflammation is an important factor in the conversion of a healthy brain into an epileptic one, a phenomenon known as epileptogenesis, offering a new entry point for prognostic tools. The development of anti-epileptogenic therapies to treat before or at disease onset is hampered by our inability to predict the severity of the disease outcome. In a rat model of temporal lobe epilepsy we aimed to assess whether in vivo non-invasive imaging of brain inflammation at disease onset was predictive of spontaneous recurrent seizures (SRS) frequency and severity of depression-like and sensorimotor-related comorbidities. To this end, translocator protein, a biomarker of inflammation, was imaged by means of positron emission tomography (PET) 2 and 4weeks post-status epilepticus using [18F]-PBR111. Translocator protein was highly upregulated 2weeks post-status epilepticus in limbic structures (up to 2.1-fold increase compared to controls in temporal lobe, P<0.001), whereas 4weeks post-status epilepticus, upregulation decreased (up to 1.6-fold increase compared to controls in temporal lobe, P<0.01) and was only apparent in a subset of these regions. Animals were monitored with video-electroencephalography during all stages of disease (acute, latent - first seizures appearing around 2weeks post-status epilepticus - and chronic phases), for a total of 12weeks, in order to determine SRS frequency for each subject (range 0.00-0.83SRS/day). We found that regional PET uptake at 2 and 4weeks post-status epilepticus correlated with the severity of depression-like and sensorimotor-related comorbidities during chronic epilepsy (P<0.05 for each test). Regional PET imaging did not correlate with SRS frequency, however, by applying a multivariate data-driven modeling approach based on translocator protein PET imaging at 2weeks post-status epilepticus, we accurately predicted the frequency of SRS (R=0.92; R2=0.86; P<0.0001) at the onset of epilepsy. This study not only demonstrates non-invasive imaging of translocator protein as a prognostic biomarker to ascertain SRS frequency, but also shows its capability to reflect the severity of depression-like and sensorimotor-related comorbidities. Our results are an encouraging step towards the development of anti-epileptogenic treatments by providing early quantitative assessment of SRS frequency and severity of comorbidities with high clinical relevance.
Collapse
|
10
|
van Vliet EA, Dedeurwaerdere S, Cole AJ, Friedman A, Koepp MJ, Potschka H, Immonen R, Pitkänen A, Federico P. WONOEP appraisal: Imaging biomarkers in epilepsy. Epilepsia 2016; 58:315-330. [PMID: 27883181 DOI: 10.1111/epi.13621] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2016] [Indexed: 01/04/2023]
Abstract
Neuroimaging offers a wide range of opportunities to obtain information about neuronal activity, brain inflammation, blood-brain barrier alterations, and various molecular alterations during epileptogenesis or for the prediction of pharmacoresponsiveness as well as postoperative outcome. Imaging biomarkers were examined during the XIII Workshop on Neurobiology of Epilepsy (XIII WONOEP) organized in 2015 by the Neurobiology Commission of the International League Against Epilepsy (ILAE). Here we present an extended summary of the discussed issues and provide an overview of the current state of knowledge regarding the biomarker potential of different neuroimaging approaches for epilepsy.
Collapse
Affiliation(s)
- Erwin A van Vliet
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Andrew J Cole
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, U.S.A
| | - Alon Friedman
- Department of Brain and Cognitive Sciences, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel.,Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Matthias J Koepp
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology and Pharmacy, Ludwig-Maximilian-University, Munich, Germany
| | - Riikka Immonen
- Department of Neurobiology, A I Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Asla Pitkänen
- Department of Neurobiology, A I Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Paolo Federico
- Departments of Clinical Neurosciences and Radiology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
11
|
Brandt C, Rankovic V, Töllner K, Klee R, Bröer S, Löscher W. Refinement of a model of acquired epilepsy for identification and validation of biomarkers of epileptogenesis in rats. Epilepsy Behav 2016; 61:120-131. [PMID: 27343814 DOI: 10.1016/j.yebeh.2016.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/09/2016] [Accepted: 05/12/2016] [Indexed: 01/23/2023]
Abstract
In rodent models in which status epilepticus (SE) is used to induce epilepsy, typically most animals develop spontaneous recurrent seizures (SRS). The SE duration for induction of epileptogenesis depends on the type of SE induction. In models with electrical SE induction, the minimum duration of SE to induce epileptogenesis in >90% of animals ranges from 3-4h. A high incidence of epilepsy is an advantage in the search of antiepileptogenic treatments, whereas it is a disadvantage in the search for biomarkers of epileptogenesis, because it does not allow a comparison of potential biomarkers in animals that either develop or do not develop epilepsy. The aim of this project was the refinement of an established SE rat model so that only ~50% of the animals develop epilepsy. For this purpose, we used an electrical model of SE induction, in which a self-sustained SE develops after prolonged stimulation of the basolateral amygdala. Previous experiments had shown that the majority of rats develop SRS after 4-h SE in this model so that the SE reduced duration to 2.5h by administering diazepam. This resulted in epilepsy development in only 50% of rats, thus reaching the goal of the project. The latent period to onset of SRS wa s >2weeks in most rats. Development of epilepsy could be predicted in most rats by behavioral hyperexcitability, whereas seizure threshold did not differentiate rats that did and did not develop SRS. The refined SE model may offer a platform to identify and validate biomarkers of epileptogenesis.
Collapse
Affiliation(s)
- Claudia Brandt
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Vladan Rankovic
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Kathrin Töllner
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Rebecca Klee
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Sonja Bröer
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
| |
Collapse
|
12
|
Liow JS, Zoghbi SS, Hu S, Hall MD, Hines CS, Shetty HU, Araneta MD, Page EM, Pike VW, Kreisl WC, Herscovitch P, Gottesman MM, Theodore WH, Innis RB. (18)F-FCWAY, a serotonin 1A receptor radioligand, is a substrate for efflux transport at the human blood-brain barrier. Neuroimage 2016; 138:134-140. [PMID: 27211474 DOI: 10.1016/j.neuroimage.2016.05.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/02/2016] [Accepted: 05/17/2016] [Indexed: 01/16/2023] Open
Abstract
Efflux transporters at the blood-brain barrier can decrease the entry of drugs and increase the removal of those molecules able to bypass the transporter. We previously hypothesized that (18)F-FCWAY, a radioligand for the serotonin 5-HT1A receptor, is a weak substrate for permeability glycoprotein (P-gp) based on its very early peak and rapid washout from human brain. To determine whether (18)F-FCWAY is a substrate for P-gp, breast cancer resistance protein (BCRP), and multidrug resistance protein (MRP1) - the three most prevalent efflux transporters at the blood-brain barrier - we performed three sets of experiments. In vitro, we conducted fluorescence-activated cell sorting (FACS) flow cytometry studies in cells over-expressing P-gp, BCRP, and MRP1 treated with inhibitors specific to each transporter and with FCWAY. Ex vivo, we measured (18)F-FCWAY concentration in plasma and brain homogenate of transporter knockout mice using γ-counter and radio-HPLC. In vivo, we conducted positron emission tomography (PET) studies to assess changes in humans who received (18)F-FCWAY during an infusion of tariquidar (2-4mg/kg iv), a potent and selective P-gp inhibitor. In vitro studies showed that FCWAY allowed fluorescent substrates to get into the cell by competitive inhibition of all three transporters at the cell membrane. Ex vivo measurements in knockout mice indicate that (18)F-FCWAY is a substrate only for P-gp and not BCRP. In vivo, tariquidar increased (18)F-FCWAY brain uptake in seven of eight subjects by 60-100% compared to each person's baseline. Tariquidar did not increase brain uptake via some peripheral mechanism, given that it did not significantly alter concentrations in plasma of the parent radioligand (18)F-FCWAY or its brain-penetrant radiometabolite (18)F-FC. These results show that (18)F-FCWAY is a weak substrate for efflux transport at the blood-brain barrier; some radioligand can enter brain, but its removal is hastened by P-gp. Although (18)F-FCWAY is not ideal for measuring 5-HT1A receptors, it demonstrates that weak substrate radioligands can be useful for measuring both increased and decreased function of efflux transporters, which is not possible with currently available radioligands such as (11)C-loperamide and (11)C-verapamil that are avid substrates for transporters.
Collapse
Affiliation(s)
- Jeih-San Liow
- Molecular Imaging Branch, NIMH/NIH, Bethesda, MD, USA.
| | - Sami S Zoghbi
- Molecular Imaging Branch, NIMH/NIH, Bethesda, MD, USA
| | - Shuo Hu
- PET Center, Xiang-Ya Hospital, Central South University, Hunan, China
| | | | - Christina S Hines
- Dept of Psychiatry, University of Texas Health Sciences Center, San Antonio, Texas, USA
| | | | | | - Emily M Page
- Molecular Imaging Branch, NIMH/NIH, Bethesda, MD, USA
| | - Victor W Pike
- Molecular Imaging Branch, NIMH/NIH, Bethesda, MD, USA
| | - William C Kreisl
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | | | | | | | | |
Collapse
|
13
|
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]
|
14
|
Investigation of therapeutic efficiency of phenytoin (PHT) labeled with radioactive 131I in the cancer cell lines. J Radioanal Nucl Chem 2016. [DOI: 10.1007/s10967-015-4119-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
15
|
Abstract
PURPOSE OF REVIEW Drug resistance is an important clinical problem: it is associated with higher rates of somatic and psychiatric comorbidities and cognitive/memory decline, with seizures being just the 'tip of the iceberg'. This review summarizes recent developments in imaging research, focusing specifically on the functional consequence of chronic epilepsies and mechanisms of drug resistance, restricted to work published in 2013. RECENT FINDINGS Functional imaging approaches reliably identify underlying specific networks in patients with different epileptic syndromes, show specific responses to certain antiepileptic drugs and differentiate between responder and nonresponder. Functional MRI (fMRI) and the intracarotid amobarbital test (IAT) are generally congruent, but fMRI may be more sensitive than IAT to right hemisphere language processing. In addition, memory fMRI supports the functional adequacy of ipsilateral structures rather than functional reserve of the contralateral hemisphere. There is further evidence from group analysis of fMRI data for a node within the ipsilateral piriform cortex to be important for seizure modulation in focal refractory epilepsies of different cortical origin. Molecular imaging with verapamil-PET identifies P-glycprotein overexpression as a mechanism contributing to drug resistance in individual patients. SUMMARY Neuroimaging in epilepsy has progressed from correlations with demographic, semiologic, neuropsychological and other observational data primarily in patients undergoing presurgical investigations to imaging network connectivity changes in epilepsy syndromes, and testing specific mechanisms underlying drug-resistant epilepsy.
Collapse
|
16
|
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]
|
17
|
Brandt C, Löscher W. Antiepileptic efficacy of lamotrigine in phenobarbital-resistant and -responsive epileptic rats: a pilot study. Epilepsy Res 2014; 108:1145-57. [PMID: 24908562 DOI: 10.1016/j.eplepsyres.2014.05.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 05/07/2014] [Accepted: 05/10/2014] [Indexed: 12/30/2022]
Abstract
About 25% of patients with epilepsy are refractory to treatment, so that new, more effective antiepileptic drugs (AEDs) are urgently needed. Animal models that simulate the clinical situation with individuals responding and not responding to treatment are important to determine mechanisms of AED resistance and develop novel more effective treatments. We have previously developed and characterized such a model in which spontaneous recurrent seizures (SRS) develop after a status epilepticus induced by sustained electrical stimulation of the basolateral amygdala. In this model, prolonged treatment of epileptic rats with phenobarbital (PB) results in two subgroups, PB responders and PB nonresponders. When PB nonresponders were treated in previous experiments with phenytoin (PHT), 83% of the PB-resistant rats were also resistant to PHT. In the present study we examined if rats with PB resistant seizures are also resistant to lamotrigine (LTG), using continuous EEG/video recording of spontaneous seizures over 10 consecutive weeks. For this purpose, a new group of epileptic rats was produced and selected by treatment with PB into responders and nonresponders. As in previous studies, PB nonresponders had a significantly higher seizure frequency before onset of treatment. During subsequent treatment with LTG, all PB nonresponders and 60% of the PB responders exhibited >75% reduction of seizure frequency and were therefore considered as LTG responders. Plasma levels of LTG did not differ significantly between responders and nonresponders. The data of this pilot study indicate that LTG is more effective than PHT to suppress seizures in PB nonresponders in this model, but that not all PB responders also respond to LTG. Overall, our data provide further evidence that AED studies in post-SE TLE models are useful in determining and comparing AED efficacy and investigating predictors and mechanisms of pharmacoresistance.
Collapse
Affiliation(s)
- Claudia Brandt
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
| |
Collapse
|
18
|
Dedeurwaerdere S, Shultz SR, Federico P, Engel J. Workshop on Neurobiology of Epilepsy appraisal: new systemic imaging technologies to study the brain in experimental models of epilepsy. Epilepsia 2014; 55:819-28. [PMID: 24836499 DOI: 10.1111/epi.12642] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2014] [Indexed: 12/14/2022]
Abstract
Modern functional neuroimaging provides opportunities to visualize activity of the entire brain, making it an indispensable diagnostic tool for epilepsy. Various forms of noninvasive functional neuroimaging are now also being performed as research tools in animal models of epilepsy and provide opportunities for parallel animal/human investigations into fundamental mechanisms of epilepsy and identification of epilepsy biomarkers. Recent animal studies of epilepsy using positron emission tomography, tractography, and functional magnetic resonance imaging were reviewed. Epilepsy is an abnormal emergent property of disturbances in neuronal networks which, even for epilepsies characterized by focal seizures, involve widely distributed systems, often in both hemispheres. Functional neuroimaging in animal models now provides opportunities to examine neuronal disturbances in the whole brain that underlie generalized and focal seizure generation as well as various types of epileptogenesis. Tremendous advances in understanding the contribution of specific properties of widely distributed neuronal networks to both normal and abnormal human behavior have been provided by current functional neuroimaging methodologies. Successful application of functional neuroimaging of the whole brain in the animal laboratory now permits investigations during epileptogenesis and correlation with deep brain electroencephalography (EEG) activity. With the continuing development of these techniques and analytical methods, the potential for future translational research on epilepsy is enormous. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.
Collapse
|