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Abstract
Temporal lobe epilepsy (TLE), exemplified by complex partial seizures, is recognized in ~30% of epileptic patients. Seizures in TLE are associated with cognitive dysfunction and are resistant to antiepileptic drug therapy in ~35% of patients. Although surgical resection of the hippocampus bestows improved seizure regulation in most cases of intractable TLE, this choice can cause lasting cognitive deficiency and reliance on antiepileptic drugs. Thus, alternative therapies that are proficient in both containing the spontaneous recurrent seizures and reversing the cognitive dysfunction are needed. The cell transplantation approach is promising in serving as an adept alternate therapy for TLE, because this strategy has shown the capability to curtail epileptogenesis when used soon after an initial precipitating brain injury, and to restrain spontaneous recurrent seizures and improve cognitive function when utilized after the occurrence of TLE. Nonetheless, this treatment needs further advancement and rigorous evaluation in animal prototypes of chronic TLE before the conceivable clinical use. It is especially vital to gauge the efficacy of distinct donor cell types, such as the hippocampal precursor cells, γ-aminobutyric acid-ergic progenitors, and neural stem cells derived from diverse human sources (including the embryonic stem cells and induced pluripotent stem cells) for longstanding seizure suppression using continuous electroencephalographic recordings for prolonged periods. Additionally, the identification of the mechanisms underlying the graft-mediated seizure suppression and improved cognitive function, and the development of apt grafting strategies that enhance the anti-seizure and pro-cognitive effects of grafts will be necessary. The goal of this review is to evaluate the progress made hitherto in this area and to discuss the prospect for cell-based therapy for TLE.
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Affiliation(s)
- Ashok K Shetty
- Institute for Regenerative Medicine, Texas A&M Health Science Center at Scott & White, Department of Molecular and Cellular Medicine, Temple, TX 76502, USA.
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Shetty AK. Promise of resveratrol for easing status epilepticus and epilepsy. Pharmacol Ther 2011; 131:269-86. [PMID: 21554899 PMCID: PMC3133838 DOI: 10.1016/j.pharmthera.2011.04.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 03/29/2011] [Indexed: 12/26/2022]
Abstract
Resveratrol (RESV; 3,5,4'-tri-hydroxy stilbene), a naturally occurring phytoalexin, is found at a high concentration in the skin of red grapes and red wine. RESV mediates a wide-range of biological activities, which comprise an increased life span, anti-ischemic, anti-cancer, antiviral, anti-aging and anti-inflammatory properties. Studies in several animal prototypes of brain injury suggest that RESV is an effective neuroprotective compound. Ability to enter the brain after a peripheral administration and no adverse effects on the brain or body are other features that are appealing for using this compound as a therapy for brain injury or neurodegenerative diseases. The goal of this review is to discuss the promise of RESV for treating acute seizures, preventing the acute seizure or status epilepticus induced development of chronic epilepsy, and easing the chronic epilepsy typified by spontaneous recurrent seizures and cognitive dysfunction. First, the various beneficial effects of RESV on the normal brain are discussed to provide a rationale for considering RESV treatment in the management of acute seizures and epilepsy. Next, the detrimental effects of acute seizures or status epilepticus on the hippocampus and the implications of post-status epilepticus changes in the hippocampus towards the occurrence of chronic epilepsy and cognitive dysfunction are summarized. The final segment evaluates studies that have used RESV as a neuroprotective compound against seizures, and proposes studies that are critically needed prior to the clinical application of RESV as a prophylaxis against the development of chronic epilepsy and cognitive dysfunction after an episode of status epilepticus or head injury.
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Affiliation(s)
- Ashok K Shetty
- Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC 27705, USA.
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Venturin GT, Greggio S, Marinowic DR, Zanirati G, Cammarota M, Machado DC, DaCosta JC. Bone marrow mononuclear cells reduce seizure frequency and improve cognitive outcome in chronic epileptic rats. Life Sci 2011; 89:229-34. [PMID: 21718708 DOI: 10.1016/j.lfs.2011.06.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 05/10/2011] [Accepted: 06/03/2011] [Indexed: 11/27/2022]
Abstract
AIMS Epilepsy affects 0.5-1% of the world's population, and approximately a third of these patients are refractory to current medication. Given their ability to proliferate, differentiate and regenerate tissues, stem cells could restore neural circuits lost during the course of the disease and reestablish the physiological excitability of neurons. This study verified the therapeutic potential of bone marrow mononuclear cells (BMMCs) on seizure control and cognitive impairment caused by experimentally induced epilepsy. MAIN METHODS Status epilepticus (SE) was induced by lithium-pilocarpine injection and controlled with diazepam 90 min after SE onset. Lithium-pilocarpine-treated rats were intravenously transplanted 22 days after SE with BMMCs obtained from enhanced green fluorescent protein (eGFP) transgenic C57BL/6 mice. Control epileptic animals were given an equivalent volume of saline or fibroblast injections. Animals were video-monitored for the presence of spontaneous recurrent seizures prior to and following the cell administration procedure. In addition, rats underwent cognitive evaluation using a Morris water maze. KEY FINDINGS Our data show that BMMCs reduced the frequency of seizures and improved the learning and long-term spatial memory impairments of epileptic rats. EGFP-positive cells were detected in the brains of transplanted animals by PCR analysis. SIGNIFICANCE The positive behavioral effects observed in our study indicate that BMMCs could represent a promising therapeutic option in the management of chronic temporal lobe epilepsy.
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Affiliation(s)
- Gianina Teribele Venturin
- Programa de Pós-Graduação em Neurociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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GABAergic neuronal precursor grafting: implications in brain regeneration and plasticity. Neural Plast 2011; 2011:384216. [PMID: 21766042 PMCID: PMC3135013 DOI: 10.1155/2011/384216] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 04/11/2011] [Indexed: 12/20/2022] Open
Abstract
Numerous neurological disorders are caused by a dysfunction of the GABAergic system that impairs or either stimulates its inhibitory action over its neuronal targets. Pharmacological drugs have generally been proved very effective in restoring its normal function, but their lack of any sort of spatial or cell type specificity has created some limitations in their use. In the last decades, cell-based therapies using GABAergic neuronal grafts have emerged as a promising treatment, since they may restore the lost equilibrium by cellular replacement of the missing/altered inhibitory neurons or modulating the hyperactive excitatory system. In particular, the discovery that embryonic ganglionic eminence-derived GABAergic precursors are able to disperse and integrate in large areas of the host tissue after grafting has provided a strong rationale for exploiting their use for the treatment of diseased brains. GABAergic neuronal transplantation not only is efficacious to restore normal GABAergic activities but can also trigger or sustain high neuronal plasticity by promoting the general reorganization of local neuronal circuits adding new synaptic connections. These results cast new light on dynamics and plasticity of adult neuronal assemblies and their associated functions disclosing new therapeutic opportunities for the near future.
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Waldau B, Hattiangady B, Kuruba R, Shetty AK. Medial ganglionic eminence-derived neural stem cell grafts ease spontaneous seizures and restore GDNF expression in a rat model of chronic temporal lobe epilepsy. Stem Cells 2010; 28:1153-64. [PMID: 20506409 DOI: 10.1002/stem.446] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Nearly 30% of patients with mesial temporal lobe epilepsy (TLE) are resistant to treatment with antiepileptic drugs. Neural stem cell (NSC) grafting into the hippocampus could offer an alternative therapy to hippocampal resection in these patients. As TLE is associated with reduced numbers of inhibitory gamma-amino butyric acid (GABA)-ergic interneurons and astrocytes expressing the anticonvulsant glial-derived neurotrophic factor (GDNF) in the hippocampus, we tested the hypothesis that grafting of NSCs that are capable of adding new GABA-ergic interneurons and GDNF-expressing astrocytes into the epileptic hippocampus restrains spontaneous recurrent motor seizures (SRMS) in chronic TLE. We grafted NSCs expanded in vitro from embryonic medial ganglionic eminence (MGE) into hippocampi of adult rats exhibiting chronic TLE with cognitive impairments. NSC grafting reduced frequencies of SRMS by 43% and stage V seizures by 90%. The duration of individual SRMS and the total time spent in seizures were reduced by 51 and 74%, respectively. Grafting did not improve the cognitive function however. Graft-derived cells (equivalent to approximately 28% of injected cells) were observed in various layers of the epileptic hippocampus where they differentiated into NeuN+ neurons (13%), S-100beta+ astrocytes (57%), and NG2+ oligodendrocyte-progenitors (3%). Furthermore, among graft-derived cells, 10% expressed GABA and 50% expressed GDNF. Additionally, NSC grafting restored GDNF in a vast majority of the hippocampal astrocytes but had no effect on neurogenesis. Thus, MGE-NSC therapy is efficacious for diminishing SRMS in chronic TLE. Addition of new GABA-ergic neurons and GDNF+ cells, and restoration of GDNF in the hippocampal astrocytes may underlie the therapeutic effect of MGE-NSC grafts.
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Affiliation(s)
- Ben Waldau
- Department of Surgery (Neurosurgery), Duke University Medical Center, Durham, North Carolina 27710, USA
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57
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Mejía-Toiber J, Márquez-Ramos JA, Díaz-Muñoz M, Peña F, Aguilar MB, Giordano M. Glutamatergic Excitation and GABA Release from a Transplantable Cell Line. Cell Transplant 2010; 19:1307-23. [DOI: 10.3727/096368910x509059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The cell line M213-2O CL-4 was derived from cell line M213-2O and further modified to express human glutamate decarboxylase (hGAD-67), the enzyme that synthesizes GABA. Brain transplants of this cell line in animal models of epilepsy have been shown to modulate seizures. However, the mechanisms that underlie such actions are unknown. The purpose of the present study was to characterize this cell line and its responsiveness to several depolarizing conditions, in order to better understand how these cells exert their effects. Intracellular GABA levels were 34-fold higher and GAD activity was 16-fold higher in clone M213-2O CL-4 than in M213-2O. Both cell lines could take up [3H]GABA in vitro, and this uptake was prevented by nipecotic acid. By combining GABA release measurements and calcium imaging in vitro, we found that high extracellular K+, zero Mg2+, or glutamate activated M213-2O CL-4 cells and resulted in GABA release. The response to glutamate appeared to be mediated by AMPA/NMDA-like receptors. High KCl-induced GABA release was prevented when a Ca2+-free Krebs solution was used, suggesting an exocytotic-like mechanism. These results indicate that the cell line M213-2O CL-4 synthesizes, releases, and takes up GABA in vitro, and can be activated by depolarizing stimuli.
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Affiliation(s)
- Jana Mejía-Toiber
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, México
| | | | - Mauricio Díaz-Muñoz
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Quéretaro, México
| | - Fernando Peña
- Departamento de Farmacobiología, CINVESTAV-Sur. Calzada de los Tenorios 235, Delegación Tlalpan, México
| | - Manuel B. Aguilar
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Quéretaro, México
| | - Magda Giordano
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, México
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Schenk GJ, Werkman T, Wadman W, Veldhuisen B, Dijkmans TF, Blaas E, Kegel L, de Kloet ER, Vreugdenhil E. Over-expression of the DCLK gene transcript CARP decreases CA3/CA1 network excitability. Brain Res 2010; 1352:21-34. [DOI: 10.1016/j.brainres.2010.07.068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 07/19/2010] [Accepted: 07/19/2010] [Indexed: 12/18/2022]
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Calcagnotto ME, Zipancic I, Piquer-Gil M, Mello LE, Alvarez-Dolado M. Grafting of GABAergic precursors rescues deficits in hippocampal inhibition. Epilepsia 2010; 51 Suppl 3:66-70. [PMID: 20618404 DOI: 10.1111/j.1528-1167.2010.02613.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
gamma-Aminobutyric acid (GABA) has an important role in the mechanism of epilepsy. Cell grafts from different sources have been performed to modulate local circuits or increase GABAergic inhibition in animal models of epilepsy. Among the different transplanted cell types, the medial ganglionic eminence (MGE)-derived cells present the best properties to be used in cell-based therapy. In this work we review previous experiences with these cells. In addition, we present new evidence showing their ability to modulate the levels of inhibition in the host brain of mice with alterations in the GABAergic system, caused by the specific ablation of hippocampal interneurons. Grafted GFP(+) MGE-derived cells occupied the area of ablation and differentiated into mature NK-1-, SOM-, PV-, CR-, and NPY-expressing interneurons. Inhibitory postsynaptic current (IPSC) frequency and amplitude on CA1 pyramidal cells of the ablated hippocampus significantly increased after transplantation, reaching levels similar to controls. Our data strongly suggest the suitability of MGE-derived cells for the treatment of neurologic conditions for which an increase or modulation of synaptic inhibition is required.
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Affiliation(s)
- Maria E Calcagnotto
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine CABIMER, Seville, Spain
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60
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Zipancic I, Calcagnotto ME, Piquer-Gil M, Mello LE, Álvarez-Dolado M. Transplant of GABAergic Precursors Restores Hippocampal Inhibitory Function in a Mouse Model of Seizure Susceptibility. Cell Transplant 2010; 19:549-64. [DOI: 10.3727/096368910x491383] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Defects in GABAergic function can cause epilepsy. In the last years, cell-based therapies have attempted to correct these defects with disparate success on animal models of epilepsy. Recently, we demonstrated that medial ganglionic eminence (MGE)-derived cells grafted into the neonatal normal brain migrate and differentiate into functional mature GABAergic interneurons. These cells are able to modulate the local level of GABA-mediated synaptic inhibition, which suggests their suitability for cell-based therapies. However, it is unclear whether they can integrate in the host circuitry and rescue the loss of inhibition in pathological conditions. Thus, as proof of principle, we grafted MGE-derived cells into a mouse model of seizure susceptibility caused by specific elimination of GABAergic interneuron subpopulations in the mouse hippocampus after injection of the neurotoxic saporin conjugated to substance P (SSP-Sap). This ablation was associated with significant decrease in inhibitory postsynaptic currents (IPSC) on CA1 pyramidal cells and increased seizure susceptibility induced by pentylenetetrazol (PTZ). Grafting of GFP+ MGE-derived cells in SSP-Sap-treated mice repopulates the hippocampal ablated zone with cells expressing molecular markers of mature interneurons. Interestingly, IPSC kinetics on CA1 pyramidal cells of ablated hippocampus significantly increased after transplantation, reaching levels similar to the normal mice. More importantly, this was associated with reduction in seizure severity and decrease in postseizure mortality induced by PTZ. Our data show that MGE-derived cells fulfill most of the requirements for an appropriate cell-based therapy, and indicate their suitability for neurological conditions where a modulation of synaptic inhibition is needed, such as epilepsy.
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Affiliation(s)
- I. Zipancic
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Seville, Spain
- Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | - M. E. Calcagnotto
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Seville, Spain
| | - M. Piquer-Gil
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Seville, Spain
| | - L. E. Mello
- Department of Physiology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - M. Álvarez-Dolado
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Seville, Spain
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Naegele JR, Maisano X, Yang J, Royston S, Ribeiro E. Recent advancements in stem cell and gene therapies for neurological disorders and intractable epilepsy. Neuropharmacology 2010; 58:855-64. [PMID: 20146928 DOI: 10.1016/j.neuropharm.2010.01.019] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 01/22/2010] [Accepted: 01/26/2010] [Indexed: 12/11/2022]
Abstract
The potential applications of stem cell therapies for treating neurological disorders are enormous. Many laboratories are focusing on stem cell treatments for CNS diseases, including spinal cord injury, Amyotrophic lateral sclerosis, Parkinson's disease, Huntington's disease, multiple sclerosis, stroke, traumatic brain injury, and epilepsy. Among the many stem cell types under testing for neurological treatments, the most common are fetal and adult brain stem cells, embryonic stem cells, induced pluripotent stem cells, and mesenchymal stem cells. An expanding toolbox of molecular probes is now available to allow analyses of neural stem cell fates prior to and after transplantation. Concomitantly, protocols are being developed to direct the fates of stem cell-derived neural progenitors, and also to screen stem cells for tumorigenicity and aneuploidy. The rapid progress in the field suggests that novel stem cell and gene therapies for neurological disorders are in the pipeline.
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Affiliation(s)
- Janice R Naegele
- Department of Biology and Program in Neuroscience and Behavior, Hall Atwater Laboratory, 52 Lawn Avenue, Wesleyan University, Middletown, CT 06459, USA.
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Reduction of seizures by transplantation of cortical GABAergic interneuron precursors into Kv1.1 mutant mice. Proc Natl Acad Sci U S A 2009; 106:15472-7. [PMID: 19706400 DOI: 10.1073/pnas.0900141106] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Epilepsy, a disease characterized by abnormal brain activity, is a disabling and potentially life-threatening condition for nearly 1% of the world population. Unfortunately, modulation of brain excitability using available antiepileptic drugs can have serious side effects, especially in the developing brain, and some patients can only be improved by surgical removal of brain regions containing the seizure focus. Here, we show that bilateral transplantation of precursor cells from the embryonic medial ganglionic eminence (MGE) into early postnatal neocortex generates mature GABAergic interneurons in the host brain. In mice receiving MGE cell grafts, GABA-mediated synaptic and extrasynaptic inhibition onto host brain pyramidal neurons is significantly increased. Bilateral MGE cell grafts in epileptic mice lacking a Shaker-like potassium channel (a gene mutated in one form of human epilepsy) resulted in significant reductions in the duration and frequency of spontaneous electrographic seizures. Our findings suggest that MGE-derived interneurons could be used to ameliorate abnormal excitability and possibly act as an effective strategy in the treatment of epilepsy.
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63
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Kriegstein AR, Pitkänen A. Commentary: the prospect of cell-based therapy for epilepsy. Neurotherapeutics 2009; 6:295-9. [PMID: 19332322 PMCID: PMC5084206 DOI: 10.1016/j.nurt.2009.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Accepted: 01/22/2009] [Indexed: 12/15/2022] Open
Abstract
About 30% of patient with epilepsy do not respond to available antiepileptic drugs. In addition to seizure suppression, novel approaches are needed to prevent or alleviate epileptogenic process after various types of brain injuries. The use of cell transplants as factories to produce endogeneous anticonvulsants or as bricks to repair abnormal ictogenic and epileptogenic neuronal circuits has generated hope that cell-based therapies could become a novel therapeutic category in the treatment arsenal of epilepsy. Herein we summarize the current status and future perspectives of cell-based therapies in the treatment of epilepsy.
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Affiliation(s)
- Arnold R Kriegstein
- Department of Neurology, University of California, San Francisco, California 94143-0525, USA.
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64
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Thompson K. Transplantation of GABA-producing cells for seizure control in models of temporal lobe epilepsy. Neurotherapeutics 2009; 6:284-94. [PMID: 19332321 PMCID: PMC5084205 DOI: 10.1016/j.nurt.2009.01.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 01/20/2009] [Accepted: 01/22/2009] [Indexed: 11/27/2022] Open
Abstract
A high percentage of patients with temporal lobe epilepsy (TLE) are refractory to conventional pharmacotherapy. The progressive neurodegenerative processes associated with a lifetime of uncontrolled seizures mandate the development of alternative approaches to treat this disease. Transplantation of inhibitory cells has been suggested as a potential therapeutic strategy to achieve seizure suppression in humans with intractable TLE. Preclinical investigations over 20 years have demonstrated that multiple cell types from several sources can produce anticonvulsant, and antiepileptogenic, effects in animal models of TLE. Transplanting GABA-producing cells, in particular, has been shown to reduce seizures in several well-established models. This review addresses experimentation using different sources of transplantable GABAergic cells, highlighting progress with fetal tissue, neural cell lines, and stem cells. Regardless of the source of the GABAergic cells used in seizure studies, common challenges have emerged. Several variables influence the anticonvulsant potential of GABA-producing cells. For example, tissue availability, graft survival, immunogenicity, tumorigenicity, and varying levels of cell migration, differentiation, and integration into functional circuits and the microenvironment provided by sclerotic tissue all contribute to the efficacy of transplanted cells. The challenge of understanding how all of these variables work in concert, in a disease process that has no well-established etiology, suggests that there is still much basic research to be done before rational cell-based therapies can be developed for TLE.
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Affiliation(s)
- Kerry Thompson
- Department of Biology, Occidental College, Los Angeles, California 90041, USA.
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Molecular and cellular basis of epileptogenesis in symptomatic epilepsy. Epilepsy Behav 2009; 14 Suppl 1:16-25. [PMID: 18835369 DOI: 10.1016/j.yebeh.2008.09.023] [Citation(s) in RCA: 214] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 09/18/2008] [Accepted: 09/18/2008] [Indexed: 12/21/2022]
Abstract
Epileptogenesis refers to a process in which an initial brain-damaging insult triggers a cascade of molecular and cellular changes that eventually lead to the occurrence of spontaneous seizures. Cellular alterations include neurodegeneration, neurogenesis, axonal sprouting, axonal injury, dendritic remodeling, gliosis, invasion of inflammatory cells, angiogenesis, alterations in extracellular matrix, and acquired channelopathies. Large-scale molecular profiling of epileptogenic tissue has provided information about the molecular pathways that can initiate and maintain cellular alterations. Currently we are learning how these pathways contribute to postinjury epileptogenesis and recovery process and whether they could be used as treatment targets.
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Nolte MW, Löscher W, Herden C, Freed WJ, Gernert M. Benefits and risks of intranigral transplantation of GABA-producing cells subsequent to the establishment of kindling-induced seizures. Neurobiol Dis 2008; 31:342-54. [PMID: 18632280 PMCID: PMC2435195 DOI: 10.1016/j.nbd.2008.05.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 05/16/2008] [Accepted: 05/18/2008] [Indexed: 02/07/2023] Open
Abstract
Neural transplantation has been investigated experimentally and clinically for the purpose of developing new treatment options for intractable epilepsy. In the present study we assessed the anticonvulsant efficacy and safety of bilateral allotransplantation of genetically engineered striatal GABAergic rat cell lines into the substantia nigra pars reticulata (SNr). Rats with previously-established seizures, induced by amygdala kindling, were used as a model of temporal lobe epilepsy. Three cell lines were transplanted: (1) immortalized GABAergic cells (M213-2O) derived from embryonic rat striatum; (2) M213-2O cells (CL4) transfected with human GAD67 cDNA to obtain higher GABA synthesis than the parent cell line; and (3) control cells (121-1I), also derived from embryonic rat striatum, but which did not show GAD expression. A second control group received injections of medium alone. Transplantation of M213-2O cells into the SNr of kindled rats resulted in significant but transient anticonvulsant effects. Neither control cells nor medium induced anticonvulsant effects. Strong tissue reactions were, however, induced in the host brain of kindled but not of non-kindled rats, and only in animals that received grafts of genetically modified CL4 cells. These tissue reactions included graft rejection, massive infiltration of inflammatory immune cells, and gliosis. The anticonvulsant effect of M213-2O cells emphasizes the feasibility of local manipulations of seizures by intranigral transplantation of GABA-producing cells. On the other hand, the present data suggest that kindling-induced activation of microglia in the SNr can enhance immune reactions to transplanted cells. In this case, under conditions of further immunological stimulation by CL4 cells, transfected with a human cDNA, substantial immune reactions occurred. Thus, it appears that the condition of the host brain and the production of foreign proteins by transplanted cells have to be considered in estimating the risks of rejection of transplants into the brain.
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Affiliation(s)
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Christiane Herden
- Institute of Pathology, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - William J. Freed
- NIDA IRP, NIH, DHHS, 333 Cassell Dr., Baltimore, MD, 21224, U.S.A
| | - Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
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