1
|
Xue T, Wang S, Chen S, Wang H, Liu C, Shi L, Bai Y, Zhang C, Han C, Zhang J. Subthalamic nucleus stimulation attenuates motor seizures via modulating the nigral orexin pathway. Front Neurosci 2023; 17:1157060. [PMID: 37214393 PMCID: PMC10196042 DOI: 10.3389/fnins.2023.1157060] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/17/2023] [Indexed: 05/24/2023] Open
Abstract
Background Focal motor seizures that originate in the motor region are a considerable challenge because of the high risk of permanent motor deficits after resection. Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a potential treatment for motor epilepsy that may enhance the antiepileptic actions of the substantia nigra pars reticulata (SNr). Orexin and its receptors have a relationship with both STN-DBS and epilepsy. We aimed to investigate whether and how STN inputs to the SNr regulate seizures and the role of the orexin pathway in this process. Methods A penicillin-induced motor epileptic model in adult male C57BL/6 J mice was established to evaluate the efficacy of STN-DBS in modulating seizure activities. Optogenetic and chemogenetic approaches were employed to regulate STN-SNr circuits. Selective orexin receptor type 1 and 2 antagonists were used to inhibit the orexin pathway. Results First, we found that high-frequency ipsilateral or bilateral STN-DBS was effective in reducing seizure activity in the penicillin-induced motor epilepsy model. Second, inhibition of STN excitatory neurons and STN-SNr projections alleviates seizure activities, whereas their activation amplifies seizure activities. In addition, activation of the STN-SNr circuits also reversed the protective effect of STN-DBS on motor epilepsy. Finally, we observed that STN-DBS reduced the elevated expression of orexin and its receptors in the SNr during seizures and that using a combination of selective orexin receptor antagonists also reduced seizure activity. Conclusion STN-DBS helps reduce motor seizure activity by inhibiting the STN-SNr circuit. Additionally, orexin receptor antagonists show potential in suppressing motor seizure activity and may be a promising therapeutic option in the future.
Collapse
Affiliation(s)
- Tao Xue
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Shu Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Shujun Chen
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Huizhi Wang
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Chong Liu
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Lin Shi
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yutong Bai
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Chunkui Zhang
- Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Chunlei Han
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jianguo Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| |
Collapse
|
2
|
Bröer S. Not Part of the Temporal Lobe, but Still of Importance? Substantia Nigra and Subthalamic Nucleus in Epilepsy. Front Syst Neurosci 2020; 14:581826. [PMID: 33381016 PMCID: PMC7768985 DOI: 10.3389/fnsys.2020.581826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/09/2020] [Indexed: 01/15/2023] Open
Abstract
The most researched brain region in epilepsy research is the temporal lobe, and more specifically, the hippocampus. However, numerous other brain regions play a pivotal role in seizure circuitry and secondary generalization of epileptic activity: The substantia nigra pars reticulata (SNr) and its direct input structure, the subthalamic nucleus (STN), are considered seizure gating nuclei. There is ample evidence that direct inhibition of the SNr is capable of suppressing various seizure types in experimental models. Similarly, inhibition via its monosynaptic glutamatergic input, the STN, can decrease seizure susceptibility as well. This review will focus on therapeutic interventions such as electrical stimulation and targeted drug delivery to SNr and STN in human patients and experimental animal models of epilepsy, highlighting the opportunities for overcoming pharmacoresistance in epilepsy by investigating these promising target structures.
Collapse
Affiliation(s)
- Sonja Bröer
- Faculty of Veterinary Medicine, Institute of Pharmacology and Toxicology, Freie Universität Berlin, Berlin, Germany
| |
Collapse
|
3
|
Sirvanci S, Akakin D, Gulcebi İdrizoglu M, Kaya OT, Karamahmutoglu T, Turgan Aşık ZN, Onat F. Ultrastructural GABA immunogold labeling in the substantia nigra pars reticulata of kindled genetic absence epilepsy rats. Ultrastruct Pathol 2020; 44:379-386. [PMID: 33118420 DOI: 10.1080/01913123.2020.1839153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Genetic Absence Epilepsy Rats from Strasbourg (GAERS) is a well-known animal model of absence epilepsy and they are resistant to electrical kindling stimulations. The present study aimed to examine possible differences in gamma-aminobutyric acid (GABA) levels and synapse counts in the substantia nigra pars reticulata anterior (SNRa) and posterior (SNRp) regions between GAERS and Wistar rats receiving kindling stimulations. Animals in the kindling group either received six stimulations in the amygdala and had grade 2 seizures or they were kindled, having grade five seizures. Rats were decapitated one hour after the last stimulation. SNR regions were obtained after vibratome sectioning of the brain tissue. GABA immunoreactivity was detected by immunogold method and synapses were counted. Sections were observed by transmission electron microscope and analyzed by Image J program. GABA density in the SNRa region of fully kindled GAERS and Wistar groups increased significantly compared to that of their corresponding grade 2 groups. The number of synapses increased significantly in kindled and grade 2 GAERS groups, compared to kindled and grade 2 Wistar groups, respectively, in the SNRa region. GABA density in the SNRp region of kindled GAERS group increased significantly compared to that of GAERS grade 2 group. In the SNRp region, both kindled and grade 2 GAERS groups were found to have increased number of synapses compared to that of GAERS control group. We concluded that both SNRa and SNRp regions may be important in modulating resistance of GAERS to kindling stimulations.
Collapse
Affiliation(s)
- Serap Sirvanci
- Department of Histology and Embryology, School of Medicine, Marmara University , Maltepe, Turkey
| | - Dilek Akakin
- Department of Histology and Embryology, School of Medicine, Marmara University , Maltepe, Turkey
| | | | - Ozlem Tugce Kaya
- Department of Histology and Embryology, School of Medicine, Marmara University , Maltepe, Turkey
| | - Tugba Karamahmutoglu
- Department of Medical Pharmacology, School of Medicine, Marmara University , Maltepe, Turkey
| | - Zehra Nur Turgan Aşık
- Department of Medical Pharmacology, School of Medicine, Marmara University , Maltepe, Turkey
| | - Filiz Onat
- Department of Medical Pharmacology, School of Medicine, Marmara University , Maltepe, Turkey
| |
Collapse
|
4
|
Backofen-Wehrhahn B, Gey L, Bröer S, Petersen B, Schiff M, Handreck A, Stanslowsky N, Scharrenbroich J, Weißing M, Staege S, Wegner F, Niemann H, Löscher W, Gernert M. Anticonvulsant effects after grafting of rat, porcine, and human mesencephalic neural progenitor cells into the rat subthalamic nucleus. Exp Neurol 2018; 310:70-83. [PMID: 30205107 DOI: 10.1016/j.expneurol.2018.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/20/2018] [Accepted: 09/07/2018] [Indexed: 12/11/2022]
Abstract
Cell transplantation based therapy is a promising strategy for treating intractable epilepsies. Inhibition of the subthalamic nucleus (STN) or substantia nigra pars reticulata (SNr) is a powerful experimental approach for remote control of different partial seizure types, when targeting the seizure focus is not amenable. Here, we tested the hypothesis that grafting of embryonic/fetal neural precursor cells (NPCs) from various species (rat, human, pig) into STN or SNr of adult rats induces anticonvulsant effects. To rationally refine this approach, we included NPCs derived from the medial ganglionic eminence (MGE) and ventral mesencephalon (VM), both of which are able to develop a GABAergic phenotype. All VM- and MGE-derived cells showed intense migration behavior after grafting into adult rats, developed characteristics of inhibitory interneurons, and survived at least up to 4 months after transplantation. By using the intravenous pentylenetetrazole (PTZ) seizure threshold test in adult rats, transient anticonvulsant effects were observed after bilateral grafting of NPCs derived from human and porcine VM into STN, but not after SNr injection (site-specificity). In contrast, MGE-derived NPCs did not cause anticonvulsant effects after grafting into STN or SNr (cell-specificity). Neither induction of status epilepticus by lithium-pilocarpine to induce neuronal damage prior to the PTZ test nor pretreatment of MGE cells with retinoic acid and potassium chloride to increase differentiation into GABAergic neurons could enhance anticonvulsant effectiveness of MGE cells. This is the first proof-of-principle study showing anticonvulsant effects by bilateral xenotransplantation of NPCs into the STN. Our study highlights the value of VM-derived NPCs for interneuron-based cell grafting targeting the STN.
Collapse
Affiliation(s)
- Bianca Backofen-Wehrhahn
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Laura Gey
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Sonja Bröer
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Björn Petersen
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Mariensee, Germany
| | - Miriam Schiff
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Annelie Handreck
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | | | - Jessica Scharrenbroich
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Michael Weißing
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Selma Staege
- Center for Systems Neuroscience, Hannover, Germany; Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Florian Wegner
- Center for Systems Neuroscience, Hannover, Germany; Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Heiner Niemann
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Mariensee, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
| |
Collapse
|
5
|
Functional integration of human neural precursor cells in mouse cortex. PLoS One 2015; 10:e0120281. [PMID: 25763840 PMCID: PMC4357458 DOI: 10.1371/journal.pone.0120281] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 01/31/2015] [Indexed: 12/14/2022] Open
Abstract
This study investigates the electrophysiological properties and functional integration of different phenotypes of transplanted human neural precursor cells (hNPCs) in immunodeficient NSG mice. Postnatal day 2 mice received unilateral injections of 100,000 GFP+ hNPCs into the right parietal cortex. Eight weeks after transplantation, 1.21% of transplanted hNPCs survived. In these hNPCs, parvalbumin (PV)-, calretinin (CR)-, somatostatin (SS)-positive inhibitory interneurons and excitatory pyramidal neurons were confirmed electrophysiologically and histologically. All GFP+ hNPCs were immunoreactive with anti-human specific nuclear protein. The proportions of PV-, CR-, and SS-positive cells among GFP+ cells were 35.5%, 15.7%, and 17.1%, respectively; around 15% of GFP+ cells were identified as pyramidal neurons. Those electrophysiologically and histological identified GFP+ hNPCs were shown to fire action potentials with the appropriate firing patterns for different classes of neurons and to display spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs). The amplitude, frequency and kinetic properties of sEPSCs and sIPSCs in different types of hNPCs were comparable to host cells of the same type. In conclusion, GFP+ hNPCs produce neurons that are competent to integrate functionally into host neocortical neuronal networks. This provides promising data on the potential for hNPCs to serve as therapeutic agents in neurological diseases with abnormal neuronal circuitry such as epilepsy.
Collapse
|
6
|
|
7
|
Handreck A, Backofen-Wehrhahn B, Bröer S, Löscher W, Gernert M. Anticonvulsant Effects by Bilateral and Unilateral Transplantation of GABA-Producing Cells into the Subthalamic Nucleus in an Acute Seizure Model. Cell Transplant 2014. [DOI: 10.3727/096368912x658944] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Neural transplantation of GABA-producing cells into key structures within seizure-suppressing circuits holds promise for medication-resistant epilepsy patients not eligible for resection of the epileptic focus. The substantia nigra pars reticulata (SNr), a basal ganglia output structure, is well known to modulate different seizure types. A recent microinjection study by our group indicated that the subthalamic nucleus (STN), which critically regulates nigral activity, might be a more promising target for focal therapy in epilepsies than the SNr. As a proof of principle, we therefore assessed the anticonvulsant efficacy of bilateral and unilateral allografting of GABA-producing cell lines into the STN using the timed intravenous pentylenetetrazole seizure threshold test, which allows repeated seizure threshold determinations in individual rats. We observed (a) that grafted cells survived up to the end of the experiments, (b) that anticonvulsant effects can be induced by bilateral transplantation into the STN using immortalized GABAergic cells derived from the rat embryonic striatum and cells additionally transfected to obtain higher GABA synthesis than the parent cell line, and (c) that anticonvulsant effects were observed even after unilateral transplantation into the STN. Neither grafting of control cells nor transplantation outside the STN induced anticonvulsant effects, emphasizing the site and cell specificity of the observed anticonvulsant effects. To our knowledge, the present study is the first showing anticonvulsant effects by grafting of GABA-producing cells into the STN. The STN can be considered a highly promising target region for modulation of seizure circuits and, moreover, has the advantage of being clinically established for functional neurosurgery.
Collapse
Affiliation(s)
- Annelie Handreck
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Bianca Backofen-Wehrhahn
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
| | - Sonja Bröer
- 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
| | - Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| |
Collapse
|
8
|
Arber C, Li M. Cortical interneurons from human pluripotent stem cells: prospects for neurological and psychiatric disease. Front Cell Neurosci 2013; 7:10. [PMID: 23493959 PMCID: PMC3595684 DOI: 10.3389/fncel.2013.00010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 01/28/2013] [Indexed: 01/20/2023] Open
Abstract
Cortical interneurons represent 20% of the cells in the cortex. These cells are local inhibitory neurons whose function is to modulate the firing activities of the excitatory projection neurons. Cortical interneuron dysfunction is believed to lead to runaway excitation underlying (or implicated in) seizure-based diseases, such as epilepsy, autism, and schizophrenia. The complex development of this cell type and the intricacies involved in defining the relative subtypes are being increasingly well defined. This has led to exciting experimental cell therapy in model organisms, whereby fetal-derived interneuron precursors can reverse seizure severity and reduce mortality in adult epileptic rodents. These proof-of-principle studies raise hope for potential interneuron-based transplantation therapies for treating epilepsy. On the other hand, cortical neurons generated from patient iPSCs serve as a valuable tool to explore genetic influences of interneuron development and function. This is a fundamental step in enhancing our understanding of the molecular basis of neuropsychiatric illnesses and the development of targeted treatments. Protocols are currently being developed for inducing cortical interneuron subtypes from mouse and human pluripotent stem cells. This review sets out to summarize the progress made in cortical interneuron development, fetal tissue transplantation and the recent advance in stem cell differentiation toward interneurons.
Collapse
Affiliation(s)
- Charles Arber
- Stem Cell Neurogenesis, MRC Clinical Sciences Centre, Imperial College London London, UK
| | | |
Collapse
|
9
|
|
10
|
Innovative treatments for epilepsy: radiosurgery and local delivery. HANDBOOK OF CLINICAL NEUROLOGY 2012. [PMID: 22939079 DOI: 10.1016/b978-0-444-52899-5.00041-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|
11
|
Stewart AM, Desmond D, Kyzar E, Gaikwad S, Roth A, Riehl R, Collins C, Monnig L, Green J, Kalueff AV. Perspectives of zebrafish models of epilepsy: What, how and where next? Brain Res Bull 2012; 87:135-43. [DOI: 10.1016/j.brainresbull.2011.11.020] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 11/20/2011] [Accepted: 11/25/2011] [Indexed: 10/14/2022]
|
12
|
JEDLICKA SABRINAS, DADARLAT MARIA, HASSELL TRAVIS, LIN YANZHU, YOUNG AARON, ZHANG MIN, IRAZOQUI PEDRO, RICKUS JENNAL. CALIBRATION OF NEUROTRANSMITTER RELEASE FROM NEURAL CELLS FOR THERAPEUTIC IMPLANTS. Int J Neural Syst 2011; 19:197-212. [DOI: 10.1142/s0129065709001963] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this work we quantified the in vitro calibration relationships between high frequency electrical stimulation and GABA and glutamate release in both mature retinoic acid differentiated P19 neurons and immortalized embryonic cortical cells engineered to express glutamic acid decarboxylase, GAD65. Extracellular glutamate and GABA was quantified by 2D gas chromatography and time of flight mass spectrometry after stimulation at varying amplitudes and frequencies. Amplitude sweeps resulted in a linear calibration for P19 neurons; the level of neurotransmitter varied over one order of magnitude from ~ 200 pg/neuron to ~ 1.2 ng/neuron for glutamate and ~ 1 ng/neuron to ~ 2 ng/neuron for GABA, depending on the stimulation amplitude. Frequency sweeps resulted in a peak release at 250 Hz for glutamate and 400 Hz for GABA in P19 cells. The GABA transporter inhibitor, nipecotic acid, increased extracellular GABA levels and decrease glutamate. In contrast the embryonic cortical cells had a strongly nonlinear dependency of release on stimulation amplitude, and a weak dependence on frequency. These cells had roughly equal extracellular glutamate and GABA levels after stimulation despite the expression of GAD65. In addition glutamate and GABA levels were insensitive to nipecotic acid. These results demonstrate an ability to calibrate and tune neurotransmitter release from neural cells using high frequency stimulation parameters.
Collapse
Affiliation(s)
- SABRINA S. JEDLICKA
- Department of Agricultural and Biological Engineering, USA
- Physiological Sensing Facility at the Bindley Bioscience Center, USA
| | | | - TRAVIS HASSELL
- Weldon School of Biomedical Engineering, USA
- Indiana University School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - YANZHU LIN
- Department of Statistics, Purdue University, West Lafayette, IN 47907, USA
| | - AARON YOUNG
- Weldon School of Biomedical Engineering, USA
| | - MIN ZHANG
- Department of Statistics, Purdue University, West Lafayette, IN 47907, USA
| | | | - JENNA L. RICKUS
- Department of Agricultural and Biological Engineering, USA
- Physiological Sensing Facility at the Bindley Bioscience Center, USA
- Weldon School of Biomedical Engineering, USA
| |
Collapse
|
13
|
Weinberg MS, McCown TJ. Current prospects and challenges for epilepsy gene therapy. Exp Neurol 2011; 244:27-35. [PMID: 22008258 DOI: 10.1016/j.expneurol.2011.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 09/16/2011] [Accepted: 10/03/2011] [Indexed: 12/25/2022]
Abstract
This review addresses the state of gene therapy research for the treatment of epilepsy. Preclinical studies have demonstrated the anti-seizure efficacy of viral vector-based gene transfer through the use of a variety of strategies - from modulating classic neurotransmitter systems to targeting or overexpressing of neuropeptide receptors in seizure-specific brain regions. While these studies provide substantive proof of principle for viral vector gene therapy, future studies must address the challenges of vector immunity, cellular specificity and effective global delivery. As these issues are resolved, viral vector gene therapy should significantly impact the treatment of intractable epilepsy.
Collapse
Affiliation(s)
- Marc S Weinberg
- University of North Carolina Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | | |
Collapse
|
14
|
De la Cruz E, Zhao M, Guo L, Ma H, Anderson SA, Schwartz TH. Interneuron progenitors attenuate the power of acute focal ictal discharges. Neurotherapeutics 2011; 8:763-73. [PMID: 21748528 PMCID: PMC3250298 DOI: 10.1007/s13311-011-0058-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Interneuron progenitors from the embryonic medial ganglionic eminence (MGE) can migrate, differentiate, and enhance local inhibition after transplantation into the postnatal cortex. Whether grafted MGE cells can reduce ictal activity in adult neocortex is unknown. We transplanted live MGE or killed cells (control) from pan green fluorescent protein expressing mice into adult mouse sensorimotor cortex. One week, 2 and 1/2 weeks, or 6 to 8 weeks after transplant, acute focal ictal epileptiform discharges were induced by injection of 4-aminopyridine (4-AP) 2 mm away from the site of transplantation. The local field potential of the events was recorded with 2 electrodes, 1 located in the 4-AP focus and the other 1 in the transplantation site. In all control groups and in the 1-week live cell transplant, 4-AP ictal discharges revealed no attenuation in power and duration from the onset site to the site of transplantation. However, 2.5 or 6 ~ 8 weeks after MGE transplants, there was a dramatic decrease in local field potential power at the MGE transplanted site with little decrease in ictal duration. Surprisingly, there was no relationship between grafted cell distribution or density and the degree of attenuation. As remarkably low graft densities still significantly reduced discharge power, these data provide further support for the therapeutic potential of interneuron precursor transplants in the treatment of neocortical epilepsy.
Collapse
Affiliation(s)
- Estanislao De la Cruz
- Department of Neurological Surgery, Weill Cornell Medical College, New York Presbyterian Hospital, New York, NY 10065 USA
| | - Mingrui Zhao
- Department of Neurological Surgery, Weill Cornell Medical College, New York Presbyterian Hospital, New York, NY 10065 USA
| | - Lihua Guo
- Department of Psychiatry, Weill Cornell Medical College, New York Presbyterian Hospital, New York, NY 10065 USA
| | - Hongtao Ma
- Department of Neurological Surgery, Weill Cornell Medical College, New York Presbyterian Hospital, New York, NY 10065 USA
| | - Stewart A. Anderson
- Department of Psychiatry, Weill Cornell Medical College, New York Presbyterian Hospital, New York, NY 10065 USA
| | - Theodore H. Schwartz
- Departments of Neurological Surgery, Neurology and Neuroscience, Weill Cornell Medical College, New York Presbyterian Hospital, New York, NY 10065 USA
| |
Collapse
|
15
|
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.
Collapse
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.
| |
Collapse
|
16
|
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.
Collapse
|
17
|
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
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.
Collapse
Affiliation(s)
- Maria E Calcagnotto
- Department of Cell Therapy and Regenerative Medicine, Andalusian Center for Molecular Biology and Regenerative Medicine CABIMER, Seville, Spain
| | | | | | | | | |
Collapse
|
20
|
Castillo CG, Mendoza S, Saavedra J, Giordano M. Lack of effect of intranigral transplants of a GABAergic cell line on absence seizures. Epilepsy Behav 2010; 18:358-65. [PMID: 20634143 DOI: 10.1016/j.yebeh.2010.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 06/03/2010] [Accepted: 06/05/2010] [Indexed: 01/12/2023]
Abstract
The substantia nigra pars reticulata (SNpr) is involved in controlling a variety of seizure phenomena. Intranigral transplants of GABAergic cells have been shown to decrease the severity of already established epileptic seizures, but the effects observed have been short-lived. This study evaluated the ability of intranigral transplants of GABA-producing cells to reduce spontaneous absence seizures in a genetic animal model for periods up to 3 months after transplantation. Intranigral transplants did not induce any behavioral deficits in the animals, and they did not form tumors; however, the transplants failed to decrease absence seizures in the genetic model. The assumed increase in intranigral levels of GABA after the transplants may be insufficient to counteract all the factors involved in generating the absence seizures; in this animal model, it may be necessary to further decrease nigral activity by implanting GABAergic cells in another area. These results bear down on the fact that cell transplants need to be tailored for each type of convulsive disorder in terms of the type of cells delivered and the location of the transplants.
Collapse
Affiliation(s)
- Claudia G Castillo
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, México
| | | | | | | |
Collapse
|
21
|
Shetty AK, Hattiangady B, Rao MS. Vulnerability of hippocampal GABA-ergic interneurons to kainate-induced excitotoxic injury during old age. J Cell Mol Med 2010. [PMID: 20141618 DOI: 10.1111/j.1582-4934.2008.00675.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Hippocampal inhibitory interneurons expressing glutamate decarboxylase-67 (GAD-67) considerably decline in number during old age. Studies in young adult animals further suggest that hippocampal GAD-67+ interneuron population is highly vulnerable to excitotoxic injury. However, the relative susceptibility of residual GAD-67+ interneurons in the aged hippocampus to excitotoxic injury is unknown. To elucidate this, using both adult and aged F344 rats, we performed stereological counting of GAD-67+ interneurons in different layers of the dentate gyrus and CA1 & CA3 sub-fields, at 3 months post-excitotoxic hippocampal injury inflicted through an intracerebroventricular administration of kainic acid (KA). Substantial reductions of GAD-67+ interneurons were found in all hippocampal layers and sub-fields after KA-induced injury in adult animals. Contrastingly, there was no significant change in GAD-67+ interneuron population in any of the hippocampal layers and sub-fields following similar injury in aged animals. Furthermore, the stability of GAD-67+ interneurons in aged rats after KA was not attributable to milder injury, as the overall extent of KA-induced hippocampal principal neuron loss was comparable between adult and aged rats. Interestingly, because of the age-related disparity in vulnerability of interneurons to injury, the surviving GAD-67+ interneuron population in the injured aged hippocampus remained comparable to that observed in the injured adult hippocampus despite enduring significant reductions in interneuron number with aging. Thus, unlike in the adult hippocampus, an excitotoxic injury to the aged hippocampus does not result in significantly decreased numbers of GAD-67+ interneurons. Persistence of GAD-67+ interneuron population in the injured aged hippocampus likely reflects an age-related change in the response of GAD-67+ interneurons to excitotoxic hippocampal injury. These results have implications towards understanding mechanisms underlying the evolution of initial precipitating injury into temporal lobe epilepsy in the elderly population.
Collapse
Affiliation(s)
- Ashok K Shetty
- Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC, USA.
| | | | | |
Collapse
|
22
|
Shetty AK, Hattiangady B, Rao MS. Vulnerability of hippocampal GABA-ergic interneurons to kainate-induced excitotoxic injury during old age. J Cell Mol Med 2010; 13:2408-23. [PMID: 20141618 DOI: 10.1111/j.1582-4934.2009.00675.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Hippocampal inhibitory interneurons expressing glutamate decarboxylase-67 (GAD-67) considerably decline in number during old age. Studies in young adult animals further suggest that hippocampal GAD-67+ interneuron population is highly vulnerable to excitotoxic injury. However, the relative susceptibility of residual GAD-67+ interneurons in the aged hippocampus to excitotoxic injury is unknown. To elucidate this, using both adult and aged F344 rats, we performed stereological counting of GAD-67+ interneurons in different layers of the dentate gyrus and CA1 & CA3 sub-fields, at 3 months post-excitotoxic hippocampal injury inflicted through an intracerebroventricular administration of kainic acid (KA). Substantial reductions of GAD-67+ interneurons were found in all hippocampal layers and sub-fields after KA-induced injury in adult animals. Contrastingly, there was no significant change in GAD-67+ interneuron population in any of the hippocampal layers and sub-fields following similar injury in aged animals. Furthermore, the stability of GAD-67+ interneurons in aged rats after KA was not attributable to milder injury, as the overall extent of KA-induced hippocampal principal neuron loss was comparable between adult and aged rats. Interestingly, because of the age-related disparity in vulnerability of interneurons to injury, the surviving GAD-67+ interneuron population in the injured aged hippocampus remained comparable to that observed in the injured adult hippocampus despite enduring significant reductions in interneuron number with aging. Thus, unlike in the adult hippocampus, an excitotoxic injury to the aged hippocampus does not result in significantly decreased numbers of GAD-67+ interneurons. Persistence of GAD-67+ interneuron population in the injured aged hippocampus likely reflects an age-related change in the response of GAD-67+ interneurons to excitotoxic hippocampal injury. These results have implications towards understanding mechanisms underlying the evolution of initial precipitating injury into temporal lobe epilepsy in the elderly population.
Collapse
Affiliation(s)
- Ashok K Shetty
- Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC, USA.
| | | | | |
Collapse
|
23
|
Calcagnotto ME, Ruiz LP, Blanco MM, Santos-Junior JG, Valente MF, Patti C, Frussa-Filho R, Santiago MF, Zipancic I, Álvarez-Dolado M, Mello LE, Longo BM. Effect of neuronal precursor cells derived from medial ganglionic eminence in an acute epileptic seizure model. Epilepsia 2010; 51 Suppl 3:71-5. [DOI: 10.1111/j.1528-1167.2010.02614.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
24
|
Boison D. Cell and gene therapies for refractory epilepsy. Curr Neuropharmacol 2010; 5:115-25. [PMID: 18615179 DOI: 10.2174/157015907780866938] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 03/07/2007] [Accepted: 03/08/2007] [Indexed: 12/20/2022] Open
Abstract
Despite recent advances in the development of antiepileptic drugs, refractory epilepsy remains a major clinical problem affecting up to 35% of patients with partial epilepsy. Currently, there are few therapies that affect the underlying disease process. Therefore, novel therapeutic concepts are urgently needed. The recent development of experimental cell and gene therapies may offer several advantages compared to conventional systemic pharmacotherapy: (i) Specificity to underlying pathogenetic mechanisms by rational design; (ii) specificity to epileptogenic networks by focal delivery; and (iii) avoidance of side effects. A number of naturally occurring brain substances, such as GABA, adenosine, and the neuropeptides galanin and neuropeptide Y, may function as endogenous anticonvulsants and, in addition, may interact with the process of epileptogenesis. Unfortunately, the systemic application of these compounds is compromised by limited bioavailability, poor penetration of the blood-brain barrier, or the widespread systemic distribution of their respective receptors. Therefore, in recent years a new field of cell and gene-based neuropharmacology has emerged, aimed at either delivering endogenous anticonvulsant compounds by focal intracerebral transplantation of bioengineered cells (ex vivo gene therapy), or by inducing epileptogenic brain areas to produce these compounds in situ (in vivo gene therapy). In this review, recent efforts to develop GABA-, adenosine-, galanin-, and neuropeptide Y- based cell and gene therapies are discussed. The neurochemical rationales for using these compounds are discussed, the advantages of focal applications are highlighted and preclinical cell transplantation and gene therapy studies are critically evaluated. Although many promising data have been generated recently, potential problems, such as long-term therapeutic efficacy, long-term safety, and efficacy in clinically relevant animal models, need to be addressed before clinical applications can be contemplated.
Collapse
Affiliation(s)
- Detlev Boison
- RS Dow Neurobiology Laboratories, Legacy Research, Portland, OR 97232, USA.
| |
Collapse
|
25
|
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.
Collapse
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
| |
Collapse
|
26
|
Ludvig N, Medveczky G, French JA, Carlson C, Devinsky O, Kuzniecky RI. Evolution and prospects for intracranial pharmacotherapy for refractory epilepsies: the subdural hybrid neuroprosthesis. EPILEPSY RESEARCH AND TREATMENT 2010; 2010:725696. [PMID: 22937227 PMCID: PMC3428620 DOI: 10.1155/2010/725696] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 11/05/2009] [Indexed: 11/17/2022]
Abstract
Intracranial pharmacotherapy is a novel strategy to treat drug refractory, localization-related epilepsies not amenable to resective surgery. The common feature of the method is the use of some type of antiepileptic drug (AED) delivery device placed inside the cranium to prevent or stop focal seizures. This distinguishes it from other nonconventional methods, such as intrathecal pharmacotherapy, electrical neurostimulation, gene therapy, cell transplantation, and local cooling. AED-delivery systems comprise drug releasing polymers and neuroprosthetic devices that can deliver AEDs into the brain via intraparenchymal, ventricular, or transmeningeal routes. One such device is the subdural Hybrid Neuroprosthesis (HNP), designed to deliver AEDs, such as muscimol, into the subdural/subarachnoid space overlaying neocortical epileptogenic zones, with electrophysiological feedback from the treated tissue. The idea of intracranial pharmacotherapy and HNP treatment for epilepsy originated from multiple sources, including the advent of implanted medical devices, safety data for intracranial electrodes and catheters, evidence for the seizure-controlling efficacy of intracerebral AEDs, and further understanding of the pathophysiology of focal epilepsy. Successful introduction of intracranial pharmacotherapy into clinical practice depends on how the intertwined scientific, engineering, clinical, neurosurgical and regulatory challenges will be met to produce an effective and commercially viable device.
Collapse
Affiliation(s)
- Nandor Ludvig
- Comprehensive Epilepsy Center, New York University School of Medicine, NYU Langone Medical Center, 223 East 34th Street, New York, NY 10016, USA
| | - Geza Medveczky
- Comprehensive Epilepsy Center, New York University School of Medicine, NYU Langone Medical Center, 223 East 34th Street, New York, NY 10016, USA
| | - Jacqueline A. French
- Comprehensive Epilepsy Center, New York University School of Medicine, NYU Langone Medical Center, 223 East 34th Street, New York, NY 10016, USA
| | - Chad Carlson
- Comprehensive Epilepsy Center, New York University School of Medicine, NYU Langone Medical Center, 223 East 34th Street, New York, NY 10016, USA
| | - Orrin Devinsky
- Comprehensive Epilepsy Center, New York University School of Medicine, NYU Langone Medical Center, 223 East 34th Street, New York, NY 10016, USA
| | - Ruben I. Kuzniecky
- Comprehensive Epilepsy Center, New York University School of Medicine, NYU Langone Medical Center, 223 East 34th Street, New York, NY 10016, USA
| |
Collapse
|
27
|
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.
Collapse
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.
| | | | | | | | | |
Collapse
|
28
|
Farin A, Liu CY, Langmoen IA, Apuzzo ML. BIOLOGICAL RESTORATION OF CENTRAL NERVOUS SYSTEM ARCHITECTURE AND FUNCTION. Neurosurgery 2009; 65:831-59; discussion 859. [DOI: 10.1227/01.neu.0000351721.81175.0b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
|
29
|
Schachter SC, Guttag J, Schiff SJ, Schomer DL. Advances in the application of technology to epilepsy: the CIMIT/NIO Epilepsy Innovation Summit. Epilepsy Behav 2009; 16:3-46. [PMID: 19780225 PMCID: PMC8118381 DOI: 10.1016/j.yebeh.2009.06.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In 2008, a group of clinicians, scientists, engineers, and industry representatives met to discuss advances in the application of engineering technologies to the diagnosis and treatment of patients with epilepsy. The presentations also provided a guide for further technological development, specifically in the evaluation of patients for epilepsy surgery, seizure onset detection and seizure prediction, intracranial treatment systems, and extracranial treatment systems. This article summarizes the discussions and demonstrates that cross-disciplinary interactions can catalyze collaborations between physicians and engineers to address and solve many of the pressing unmet needs in epilepsy.
Collapse
Affiliation(s)
- Steven C Schachter
- Center for Integration of Medicine and Innovative Technology, Boston, MA, USA.
| | | | | | | |
Collapse
|
30
|
Jing M, Shingo T, Yasuhara T, Kondo A, Morimoto T, Wang F, Baba T, Yuan WJ, Tajiri N, Uozumi T, Murakami M, Tanabe M, Miyoshi Y, Zhao S, Date I. The combined therapy of intrahippocampal transplantation of adult neural stem cells and intraventricular erythropoietin-infusion ameliorates spontaneous recurrent seizures by suppression of abnormal mossy fiber sprouting. Brain Res 2009; 1295:203-17. [PMID: 19646969 DOI: 10.1016/j.brainres.2009.07.079] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 07/21/2009] [Accepted: 07/22/2009] [Indexed: 11/27/2022]
Abstract
Adult neural stem cells (NSCs) possess the potentials to self-renew and exert neuroprotection. In this study, we examined whether adult NSCs had anti-epileptic effects in rats with status epilepticus (SE) induced by kainic acid (KA) and whether co-administration of erythropoietin (EPO) enhanced anti-epileptic effects or cell survival. Adult NSCs were transplanted into KA-lesioned hippocampus with or without intracerebroventricular EPO infusion. Electronic encephalography (EEG) was recorded for 3 weeks after transplantation. The frequency of abnormal spikes in rats with NSC transplantation decreased significantly compared to those of rats without NSC transplantation. Most of the transplanted NSCs differentiated into GFAP-positive astrocytes. EPO infusion significantly enhanced the survival of NSCs, but not neuronal differentiation or migration. NSC transplantation increased the number of neuropeptide Y (NPY) and glutamic acid decarboxylase 67 (GAD67)-positive interneurons. NSC transplantation also suppressed mossy fiber sprouting into the inner molecular layer with subsequent reduction of hippocampal excitability, which finally prevented the development of spontaneous recurrent seizures in adult rats after KA-induced SE. This study might shed light on the cytoarchitectural mechanisms of temporal lobe epilepsy as well as clarify the effect of adult NSC transplantation with intracerebroventricular EPO infusion for temporal lobe epilepsy.
Collapse
Affiliation(s)
- Meng Jing
- Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences 2-5-1, Shikata-cho, Okayama 700-8558, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Barcia JA, Gallego JM. Intraventricular and intracerebral delivery of anti-epileptic drugs in the kindling model. Neurotherapeutics 2009; 6:337-43. [PMID: 19332328 PMCID: PMC5084212 DOI: 10.1016/j.nurt.2009.01.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Revised: 01/19/2009] [Accepted: 01/22/2009] [Indexed: 11/20/2022] Open
Abstract
A means to avoid the pharmacokinetic problems affecting the anti-epileptic drugs may be their direct intracerebroventricular (ICV) or intracerebral delivery. This approach may achieve a greater drug concentration at the epileptogenic area while minimizing it in other brain or systemic areas, and thus it could be an interesting therapeutic alternative in drug-resistant epilepsies. The objective of this article is to review a series of experiments, ranging from actute ICV injection to continuous intracerebral infusion of anti-epileptic drugs or grafting of neurotransmitter producing cells, in experimental models, especially in the kindling model of epilepsy in the rat. Acute ICV injection of phenytoin, phenobarbital or carbamacepine is able to diminish the intensity of kindling seizures, but it is also associated with a high neurologic toxicity, especially phenobarbital. Continuous ICV infusion of anti-epileptic drugs can effectively control seizures, but neurologic toxicity is not improved compared with systemic delivery. However, systemic toxicity may be improved, as in the case of valproic acid, whose continuous ICV infusion results in very low plasmatic or hepatic drug concentrations. Continuous intracerebral infusion at the epileptogenic area was studied as an alternative to minimize neurologic toxicity. Thus, intra-amygdalar infusion of gamma-aminobutyric acid (GABA) controls seizures with minimal neurotoxicity in amygdala-kindled rats. Similarly, continuous infusion of GABA into the dorsomedian nucleus of the thalamus improves seizure spread, while not affecting the local epileptogenic activity at the amygdala. Grafting of GABA releasing cells may reduce kindling parameter severity without behavioral side effects. We may conclude that ICV or intracerebral delivery of anti-epileptic drugs or neurotransmitters may be a useful technique to modulate epilepsy.
Collapse
Affiliation(s)
- Juan A Barcia
- Servicio de Neurocirugía and Instituto de Neurociencias, Hospital Clínico San Carlos, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | | |
Collapse
|
32
|
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.
Collapse
Affiliation(s)
- Arnold R Kriegstein
- Department of Neurology, University of California, San Francisco, California 94143-0525, USA.
| | | |
Collapse
|
33
|
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.
Collapse
Affiliation(s)
- Kerry Thompson
- Department of Biology, Occidental College, Los Angeles, California 90041, USA.
| |
Collapse
|
34
|
Maisano X, Carpentino J, Becker S, Lanza R, Aaron G, Grabel L, Naegele JR. Embryonic stem cell-derived neural precursor grafts for treatment of temporal lobe epilepsy. Neurotherapeutics 2009; 6:263-77. [PMID: 19332319 PMCID: PMC2830617 DOI: 10.1016/j.nurt.2009.01.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 01/15/2009] [Accepted: 01/17/2009] [Indexed: 01/08/2023] Open
Abstract
Complex partial seizures arising from mesial temporal lobe structures are a defining feature of mesial temporal lobe epilepsy (TLE). For many TLE patients, there is an initial traumatic head injury that is the precipitating cause of epilepsy. Severe TLE can be associated with neuropathological changes, including hippocampal sclerosis, neurodegeneration in the dentate gyrus, and extensive reorganization of hippocampal circuits. Learning disabilities and psychiatric conditions may also occur in patients with severe TLE for whom conventional anti-epileptic drugs are ineffective. Novel treatments are needed to limit or repair neuronal damage, particularly to hippocampus and related limbic regions in severe TLE and to suppress temporal lobe seizures. A promising therapeutic strategy may be to restore inhibition of dentate gyrus granule neurons by means of cell grafts of embryonic stem cell-derived GABAergic neuron precursors. "Proof-of-concept" studies show that human and mouse embryonic stem cell-derived neural precursors can survive, migrate, and integrate into the brains of rodents in different experimental models of TLE. In addition, studies have shown that hippocampal grafts of cell lines engineered to release GABA or other anticonvulsant molecules can suppress seizures. Furthermore, transplants of fetal GABAergic progenitors from the mouse or human brain have also been shown to suppress the development of seizures. Here, we review these relevant studies and highlight areas of future research directed toward producing embryonic stem cell-derived GABAergic interneurons for cell-based therapies for treating TLE.
Collapse
Affiliation(s)
- Xu Maisano
- grid.268117.b0000000122937601Program in Neuroscience and Behavior, Department of Biology, Wesleyan University, 06459 Middletown, Connecticut
| | - Joseph Carpentino
- grid.15276.370000000419368091Program in Stem Cell Biology and Regenerative Medicine, McKnight Brain Institute, University of Florida, 32610 Gainesville, Florida
| | - Sandy Becker
- grid.421980.6Advanced Cell Technology, Inc., 01605 Worcester, Massachusetts
| | - Robert Lanza
- grid.421980.6Advanced Cell Technology, Inc., 01605 Worcester, Massachusetts
| | - Gloster Aaron
- grid.268117.b0000000122937601Program in Neuroscience and Behavior, Department of Biology, Wesleyan University, 06459 Middletown, Connecticut
| | - Laura Grabel
- grid.268117.b0000000122937601Program in Neuroscience and Behavior, Department of Biology, Wesleyan University, 06459 Middletown, Connecticut
| | - Janice R. Naegele
- grid.268117.b0000000122937601Program in Neuroscience and Behavior, Department of Biology, Wesleyan University, 06459 Middletown, Connecticut
- grid.268117.b0000000122937601Department of Biology, Hall-Atwater Laboratory, Wesleyan University, 52 Lawn Avenue, 06459-0170 Middletown, CT
| |
Collapse
|
35
|
Yuan TF. Transplantation of autonomous rhythm neurons as new approach of deep brain stimulation. Brain Stimul 2009; 2:55-6. [PMID: 20633403 DOI: 10.1016/j.brs.2008.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 07/23/2008] [Accepted: 09/05/2008] [Indexed: 10/21/2022] Open
|
36
|
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.
Collapse
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
| |
Collapse
|
37
|
Hattiangady B, Rao MS, Shetty AK. Grafting of striatal precursor cells into hippocampus shortly after status epilepticus restrains chronic temporal lobe epilepsy. Exp Neurol 2008; 212:468-81. [PMID: 18579133 DOI: 10.1016/j.expneurol.2008.04.040] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2008] [Revised: 04/17/2008] [Accepted: 04/25/2008] [Indexed: 01/05/2023]
Abstract
Status epilepticus (SE) typically progresses into temporal lobe epilepsy (TLE) typified by complex partial seizures. Because sizable fraction of patients with TLE exhibit chronic seizures that are resistant to antiepileptic drugs, alternative therapies that are efficient for diminishing SE-induced chronic epilepsy have great significance. We hypothesize that bilateral grafting of appropriately treated striatal precursor cells into hippocampi shortly after SE is efficacious for diminishing SE-induced chronic epilepsy through long-term survival and differentiation into GABA-ergic neurons. We induced SE in adult rats via graded intraperitoneal injections of kainic acid, bilaterally placed grafts of striatal precursors (pre-treated with fibroblast growth factor-2 and caspase inhibitor) into hippocampi at 4 days post-SE, and examined long-term effects of grafting on spontaneous recurrent motor seizures (SRMS). Analyses at 9-12 months post-grafting revealed that, the overall frequency of SRMS was 67-89% less than that observed in SE-rats that underwent sham-grafting surgery and epilepsy-only controls. Graft cell survival was approximately 33% of injected cells and approximately 69% of surviving cells differentiated into GABA-ergic neurons, which comprised subclasses expressing calbindin, parvalbumin, calretinin and neuropeptide Y. Grafting considerably preserved hippocampal calbindin but had no effects on aberrant mossy fiber sprouting. The results provide novel evidence that bilateral grafting of appropriately treated striatal precursor cells into hippocampi shortly after SE is proficient for greatly reducing the frequency of SRMS on a long-term basis in the chronic epilepsy period. Presence of a large number of GABA-ergic neurons in grafts further suggests that strengthening of the inhibitory control in host hippocampi likely underlies the beneficial effects mediated by grafts.
Collapse
Affiliation(s)
- Bharathi Hattiangady
- Department of Surgery (Neurosurgery) Duke University Medical Center, Durham, NC 27710, USA
| | | | | |
Collapse
|
38
|
Castillo CG, Mendoza-Trejo S, Aguilar MB, Freed WJ, Giordano M. Intranigral transplants of a GABAergic cell line produce long-term alleviation of established motor seizures. Behav Brain Res 2008; 193:17-27. [PMID: 18571743 DOI: 10.1016/j.bbr.2008.04.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 04/10/2008] [Accepted: 04/18/2008] [Indexed: 11/26/2022]
Abstract
We have previously shown that intranigral transplants of immortalized GABAergic cells decrease the number of kainic acid-induced seizures [Castillo CG, Mendoza S, Freed WJ, Giordano M. Intranigral transplants of immortalized GABAergic cells decrease the expression of kainic acid-induced seizures in the rat. Behav Brain Res 2006;171:109-15] in an animal model. In the present study, recurrent spontaneous behavioral seizures were established by repeated systemic injections of this excitotoxin into male Sprague-Dawley rats. After the seizures had been established, cells were transplanted into the substantia nigra. Animals with transplants of control cells (without hGAD67 expression) or with sham transplants showed a death rate of more than 40% over the 12 weeks of observation, whereas in animals with M213-2O CL-4 transplants, the death rate was reduced to less than 20%. The M213-2O CL-4 transplants significantly reduced the percentage of animals showing behavioral seizures; animals with these transplants also showed a lower occurrence of stage V seizures than animals in the other groups. In vivo and in vitro analyses provided evidence that the GABAergic cells show sustained expression of both GAD67 and hGAD67 cDNA, as well as increased gamma-aminobutyric acid (GABA) levels in the ventral mesencephalon of transplanted animals. Therefore, transplantation of GABA-producing cells can produce long-term alleviation of behavioral seizures in an animal model.
Collapse
Affiliation(s)
- Claudia G Castillo
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro, Qro. 76230, Mexico.
| | | | | | | | | |
Collapse
|
39
|
Cell and gene therapies in epilepsy – promising avenues or blind alleys? Trends Neurosci 2008; 31:62-73. [DOI: 10.1016/j.tins.2007.11.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 11/28/2007] [Accepted: 11/30/2007] [Indexed: 11/23/2022]
|
40
|
Raedt R, Van Dycke A, Vonck K, Boon P. Cell therapy in models for temporal lobe epilepsy. Seizure 2007; 16:565-78. [PMID: 17566770 DOI: 10.1016/j.seizure.2007.05.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 04/03/2007] [Accepted: 05/08/2007] [Indexed: 12/18/2022] Open
Abstract
For patients with refractory epilepsy it is important to search for alternative treatments. One of these potential treatments could be introducing new cells or modulating endogenous neurogenesis to reconstruct damaged epileptic circuits or to bring neurotransmitter function back into balance. In this review the scientific basis of these cell therapy strategies is discussed and the results are critically evaluated. Research on cell transplantation strategies has mainly been performed in animal models for temporal lobe epilepsy, in which seizure foci or seizure propagation pathways are targeted. Promising results have been obtained, although there remains a lot of debate about the relevance of the animal models, the appropriate target for transplantation, the suitable cell source and the proper time point for transplantation. From the presented studies it should be evident that transplanted cells can survive and sometimes even integrate in an epileptic brain and in a brain that is subjected to epileptogenic interventions. There is evidence that transplanted cells can partially restore damaged structures and/or release substances that modulate existent or induced hyperexcitability. Even though several studies show encouraging results, more studies need to be done in animal models with spontaneous seizures in order to have a better comparison to the human situation.
Collapse
Affiliation(s)
- R Raedt
- Laboratory for Clinical and Experimental Neurophysiology, Department of Neurology, Ghent University Hospital, De Pintelaan 145, B-9000 Ghent, Belgium.
| | | | | | | |
Collapse
|
41
|
Rao MS, Hattiangady B, Rai KS, Shetty AK. Strategies for promoting anti-seizure effects of hippocampal fetal cells grafted into the hippocampus of rats exhibiting chronic temporal lobe epilepsy. Neurobiol Dis 2007; 27:117-32. [PMID: 17618126 PMCID: PMC3612502 DOI: 10.1016/j.nbd.2007.03.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 03/22/2007] [Accepted: 03/27/2007] [Indexed: 01/10/2023] Open
Abstract
Efficacy of hippocampal fetal cell (HFC) grafting for restraining spontaneous recurrent motor seizures (SRMS) in chronic temporal lobe epilepsy (TLE) is unknown. We investigated both survival and anti-seizure effects of 5'-bromodeoxyuridine (BrdU) labeled embryonic day 19 (E19) HFC grafts pretreated with different neurotrophic factors and a caspase inhibitor. Grafts were placed bilaterally into the hippocampi of F344 rats exhibiting kainate (KA) induced chronic TLE, where the frequency of SRMS varied from 3.0 to 3.5 seizures/8-h duration. The first group received standard (untreated) HFC grafts, the second group received HFC grafts pretreated and transplanted with brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and caspase inhibitor Ac-YVAD-cmk (BNC-treated HFC grafts), the third group received HFC grafts pretreated and transplanted with fibroblast growth factor-2 (FGF-2) and caspase inhibitor Ac-YVAD-cmk (FC-treated HFC grafts), and the fourth group served as epilepsy-only controls. Epileptic rats receiving standard HFC grafts exhibited 119% increase in the frequency of SRMS at 2 months post-grafting consistent with 125% increase in seizure frequency observed in epilepsy-only controls during the same period. However, in epileptic rats receiving HFC grafts treated with BNC or FC, the frequency of SRMS was 33-39% less than their pre-transplant scores and 73-76% less than rats receiving standard HFC grafts or epilepsy-only rats. The yield of surviving neurons was equivalent to 30% of injected cells in standard HFC grafts, 57% in HFC grafts treated with BNC and 98% in HFC grafts treated with FC. Thus, standard HFC grafts survive poorly in the chronically epileptic hippocampus and fail to restrain the progression of chronic TLE. In contrast, HFCs treated and grafted with BNC or FC survive robustly in the chronically epileptic hippocampus, considerably reduce the frequency of SRMS and blunt the progression of chronic TLE.
Collapse
Affiliation(s)
| | | | | | - Ashok K. Shetty
- Corresponding author. Division of Neurosurgery, Box 3807, Duke University Medical Center, Durham NC 27710, USA. (A.K. Shetty)
| |
Collapse
|
42
|
Noe' F, Nissinen J, Pitkänen A, Gobbi M, Sperk G, During M, Vezzani A. Gene therapy in epilepsy: the focus on NPY. Peptides 2007; 28:377-83. [PMID: 17196301 DOI: 10.1016/j.peptides.2006.07.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 07/24/2006] [Indexed: 01/16/2023]
Abstract
Gene therapy represents an innovative and promising alternative for the treatment of epileptic patients who are resistant to conventional antiepileptic drugs. Among the various approaches for the application of gene therapy in the treatment of CNS disorders, recombinant viral vectors have been most widely used so far. Several gene targets could be used to correct the compromized balance between inhibitory and excitatory transmission in epilepsy. Transduction of neuropeptide genes such as galanin and neuropeptide Y (NPY) in specific brain areas in experimental models of seizures resulted in significant anticonvulsant effects. In particular, the long-lasting NPY over-expression obtained in the rat hippocampus using intracerebral application of recombinant adeno-associated viral (AAV) vectors reduced the generalization of seizures from their site of onset, delayed acquisition of fully kindled seizures and afforded neuroprotection. These results establish a proof-of-principle for the applicability of AAV-NPY vectors for the inhibition of seizures in epilepsy. Additional investigations are required to demonstrate a therapeutic role of gene therapy in chronic models of seizures and to address in more detail safety concerns and possible side-effects.
Collapse
Affiliation(s)
- Francesco Noe'
- Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via Eritrea 62, 20157 Milano, Italy
| | | | | | | | | | | | | |
Collapse
|
43
|
de Lima AD, Lima BD, Voigt T. Earliest spontaneous activity differentially regulates neocortical GABAergic interneuron subpopulations. Eur J Neurosci 2007; 25:1-16. [PMID: 17241262 DOI: 10.1111/j.1460-9568.2006.05251.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Although less than one quarter of all neurons in the cerebral cortex are GABAergic, these neurons are morphologically diverse and their physiological complexity decisively moulds the network physiology. An important question is how different subpopulations of GABAergic neurons are regulated numerically during development. In rat neocortical cultures, neuronal precursors continue to divide, generating both GABAergic and non-GABAergic neurons. In vitro generated GABAergic neurons form a population of uniquely small, mostly fusiform neurons that differ in size and morphology from older, in situ generated, large stellate GABAergic neurons. In a large series of experiments we investigated the impact of neuronal activity on the development of these two subpopulations of GABA interneurons present in cortical networks during the first 2 weeks in vitro. Here we show that a moderate increase in the generation of GABAergic neurons was achieved by blocking activity with tetrodotoxin, indicating that intrinsic spontaneous activity inhibits GABAergic neurogenesis in culture. Antagonists to ionotropic glutamate receptor and/or GABA(A) receptor did not significantly alter GABAergic generation but agonists to these receptors showed a time-sensitive regulation of the size of small and large GABAergic neuronal subpopulations. Further, our results indicate that alterations of cell generation by activity manipulations might be overwritten by later activity effects on the survival of GABAergic cell populations.
Collapse
Affiliation(s)
- Ana D de Lima
- Otto-von-Guericke University, Department of Developmental Physiology, Institute of Physiology, Leipziger Strasse 44, D-39120 Magdeburg, Germany
| | | | | |
Collapse
|
44
|
Castillo CG, Mendoza S, Freed WJ, Giordano M. Intranigral transplants of immortalized GABAergic cells decrease the expression of kainic acid-induced seizures in the rat. Behav Brain Res 2006; 171:109-15. [PMID: 16677720 DOI: 10.1016/j.bbr.2006.03.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 03/16/2006] [Accepted: 03/20/2006] [Indexed: 01/14/2023]
Abstract
Repeated systemic administration of low doses of kainic acid (KA) induces spontaneous convulsive seizures [Hellier JL, Patrylo PR, Buckmaster PS, Dudek FE. Recurrent spontaneous motor seizures after repeated low-dose systemic treatment with kainate: assessment of a rat model of temporal lobe epilepsy. Epilepsy Res 1998;31:73-84]. In this study, male Sprague-Dawley animals received intranigral transplants of a control cell line M213-2O, or a cell line transfected with human GAD67 cDNA (M213-2O CL4) [Conejero-Goldberg C, Tornatore C, Abi-Saab W, Monaco MC, Dillon-Carter O, Vawter M, et al. Transduction of human GAD67 cDNA into immortalized striatal cell lines using an Epstein-Barr virus-based plasmid vector increases GABA content. Exp Neurol 2000;161:453-61], or no transplant. Eight weeks after transplantation surgery, KA was administered (5 mg/kg/h) until animals reached stage V seizures as described by Racine [Racine RJ. Modification of seizure activity by electrical stimulation. II. Motor seizure. Electroencephalogr Clin Neurophysiol 1972;32:281-94]. The group transplanted with CL4 required a larger dose of KA and a longer latency to reach a stage V seizure. In addition, this group exhibited significantly fewer stage III and IV seizures. These results indicate that intranigral transplants of a GABA-producing cell line can decrease the number of kainic acid-induced seizures.
Collapse
Affiliation(s)
- Claudia G Castillo
- Department of Cognitive and Behavioural Neurobiology, Instituto de Neurobiología, Campus Juriquilla, Universidad Nacional Autónoma de México, Querétaro
| | | | | | | |
Collapse
|
45
|
Kumar SS, Wen X, Yang Y, Buckmaster PS. GABAA receptor-mediated IPSCs and alpha1 subunit expression are not reduced in the substantia nigra pars reticulata of gerbils with inherited epilepsy. J Neurophysiol 2006; 95:2446-55. [PMID: 16407426 DOI: 10.1152/jn.01173.2005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Domestic Mongolian gerbils, a model of inherited epilepsy, begin having spontaneous seizures at approximately 1.5 mo of age, making it possible to evaluate them during epileptic and pre-epileptic stages. Previous studies have shown that GABA binding is reduced in the substantia nigra pars reticulata (SNr) of both epileptic and pre-epileptic gerbils compared with controls, suggesting that reduced expression of GABAA receptors in SNr might be epileptogenic in this model. To test this hypothesis, we measured the expression of the GABAA receptor alpha1 subunit, the dominant alpha subunit expressed in the SNr, and evaluated GABAA receptor-mediated postsynaptic currents in SNr neurons. GABA(A) alpha1 subunit mRNA levels in substantia nigra-rich tissue from pre-epileptic animals were similar to controls, and immunocytochemistry for the alpha1 subunit showed similar strong expression in the SNr in both groups. Western analysis confirmed that expression of the alpha1 subunit protein was similar in substantia nigra-rich tissue from pre-epileptic and control gerbils. The frequency and amplitude of spontaneous inhibitory postsynaptic currents (IPSCs) and the frequency of miniature (m)IPSCs in SNr neurons of pre-epileptic gerbil were similar to those of controls. The amplitude of mIPSCs in the pre-epileptics was significantly larger than controls. Zolpidem, an alpha1 subunit-specific modulator of the GABAA receptor, was equally efficacious in prolonging the decay time of mIPSCs in both groups. Hence, contrary to the predictions of the hypothesis, mRNA and protein expression levels of the major GABAA receptor alpha subunit were normal, and neurons of the SNr in pre-epileptic gerbils displayed normal or enhanced IPSC frequencies and amplitudes. Therefore reduced expression of GABAA receptors in SNr is not likely to be an epileptogenic mechanism in this model.
Collapse
Affiliation(s)
- Sanjay S Kumar
- Department of Comparative Medicine, Stanford University, Stanford, CA 94305-5342, USA
| | | | | | | |
Collapse
|
46
|
Thompson KW. Genetically engineered cells with regulatable GABA production can affect afterdischarges and behavioral seizures after transplantation into the dentate gyrus. Neuroscience 2005; 133:1029-37. [PMID: 15927406 DOI: 10.1016/j.neuroscience.2005.03.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2004] [Revised: 02/15/2005] [Accepted: 03/02/2005] [Indexed: 11/24/2022]
Abstract
Intractable seizures originating in the mesial temporal lobe can often be controlled by resection. An alternative to removing hippocampal tissue may be transplantation of GABA-producing cells. Neural cell transplantation has been performed in hundreds of patients, including some with temporal lobe epilepsy. This study evaluates the seizure-suppressing capabilities of engineered GABA-producing cells transplanted into the dentate gyrus. Immortalized neurons were engineered to produce GABA under the control of doxycycline. The cells were characterized for GABA production in vitro and for their ability to raise GABA concentrations in vivo. Cells were transplanted bilaterally into the dentate gyrus of rats and tested in two separate paradigms. Afterdischarge thresholds and durations were tested with granule cell stimulation, and the development of behavioral seizures, induced by daily electrical stimulation of the major excitatory input pathway into the dentate gyrus, was assessed in the presence, or the absence, of doxycycline. GABA production was under the tight control of doxycycline. Cells engineered to produce GABA raised tissue GABA concentrations in the hippocampus compared with non GABA-producing cells, and this was abolished when doxycycline was administered. GABA-producing cells raised the threshold, and shortened the duration of hippocampal afterdischarges elicited by granule cell stimulation. Lastly, the appearance of stage 5 seizures was slowed in the kindling paradigm, compared with a group that received non-GABA-producing cells, and compared with a group that received GABA-producing cells but was administered doxycycline. This study shows that targeted hippocampal implants of genetically engineered cells have the potential to raise GABA levels and to affect seizure development. The ability to suppress the production of GABA, and to modulate the physiological effects of the transplanted cells provides an important level of experimental control. These techniques, combined with stem cell technology, may advance cell-based therapies for epilepsy and other diseases of the CNS.
Collapse
Affiliation(s)
- K W Thompson
- VA Greater Los Angeles Healthcare System/UCLA Department of Neurology, Building 114, Room 137, 11301 Wilshire Boulevard, Los Angeles, CA 90073, USA.
| |
Collapse
|
47
|
Güttinger M, Fedele D, Koch P, Padrun V, Pralong WF, Brüstle O, Boison D. Suppression of kindled seizures by paracrine adenosine release from stem cell-derived brain implants. Epilepsia 2005; 46:1162-9. [PMID: 16060924 DOI: 10.1111/j.1528-1167.2005.61804.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE Stem cells and their derivatives have emerged as a promising tool for cell-based drug delivery because of (a) their unique ability to differentiate into various somatic cell types, (b) the virtually unlimited donor source for transplantation, and (c) the advantage of being amenable to a wide spectrum of genetic manipulations. Previously, adenosine-releasing embryonic stem (ES) cells have been generated by disruption of both alleles of adenosine kinase (Adk-/-). Lack of ADK did not compromise the cells' differentiation potential into embryoid bodies or glial precursor cells. The aim of the present study was to investigate the potential of differentiated Adk-/- ES cell progeny for seizure suppression by paracrine adenosine release. METHODS To isolate paracrine effects of stem cell-derived implants from effects caused by network integration, ES cell-derived embryoid bodies and glial precursor cells were encapsulated into semipermeable polymer membranes and grafted into the lateral brain ventricles of kindled rats. RESULTS While seizure activity in kindled rats with wild-type Adk+/+ implants remained unaltered, rats with adenosine-releasing Adk-/- ES cell-derived implants displayed transient protection from convulsive seizures and a profound reduction of afterdischarge activity in EEG recordings. Long-term seizure suppression was precluded by limited viability of the encapsulated cells. CONCLUSIONS We thereby provide a proof-of-principle that Adk-/- ES cell-derived brain implants can suppress seizure activity by a paracrine mode of action. Adk-deficient stem cells therefore represent a potential tool for the treatment of epileptic disorders.
Collapse
Affiliation(s)
- Martin Güttinger
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
| | | | | | | | | | | | | |
Collapse
|
48
|
Rüschenschmidt C, Koch PG, Brüstle O, Beck H. Functional Properties of ES Cell-Derived Neurons Engrafted into the Hippocampus of Adult Normal and Chronically Epileptic Rats. Epilepsia 2005; 46 Suppl 5:174-83. [PMID: 15987274 DOI: 10.1111/j.1528-1167.2005.01028.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE Embryonic stem (ES) cell-based therapy strategies are thought to bear considerable promise in chronic neurologic disorders. Nonetheless, studies addressing the functional properties of ES cell-derived progeny after transplantation into the adult, pathologically modified CNS are scarce. METHODS We therefore transplanted ES cell-derived neural precursors expressing enhanced green fluorescent protein only in neuronal progeny bilaterally into the hippocampi of pilocarpine-treated chronically epileptic and sham-control rats. Whole-cell patch-clamp recordings of identified ES cell-derived neurons (ESNs) in hippocampal slices were performed 13 to 34 days after transplantation. RESULTS Most ESNs were found in clusters at the transplant site and did not migrate into host tissue. However, they gave rise to a dense network of processes extending over large distances into the host tissue. All ESNs possessed the ability to generate action potentials and expressed voltage-gated Na+ and K+ currents, as well as hyperpolarization-activated currents. Likewise, most ESNs received non-N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA)A receptor-mediated synaptic input. Both types of synapses displayed intact short-term plasticity. An unusual feature of the majority of ESNs was the occurrence of spontaneous pacemaking activity at frequencies approximately 3 Hertz. No obvious differences were found between the functional properties of ESNs in sham-control and in pilocarpine-treated rats. CONCLUSIONS After transplantation into adult control and epileptic rats, ESNs displayed intrinsic and synaptic properties characteristic of neurons. Even though ESNs remained close to the transplant site, the formation of extensive networks of graft-derived processes may be useful for ES cell-based substance delivery.
Collapse
Affiliation(s)
- Christiane Rüschenschmidt
- Institute of Reconstructive Neurobiology, University of Bonn Medical Center and Hertie Foundation, Bonn, Germany
| | | | | | | |
Collapse
|
49
|
Gernert M, Fedrowitz M, Wlaz P, Löscher W. Subregional changes in discharge rate, pattern, and drug sensitivity of putative GABAergic nigral neurons in the kindling model of epilepsy. Eur J Neurosci 2004; 20:2377-86. [PMID: 15525279 DOI: 10.1111/j.1460-9568.2004.03699.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The substantia nigra pars reticulata (SNr) is thought to act as a seizure-gating mechanism in kindling and other epilepsy models. We investigated whether the kindling process induces site-specific (anterior-posterior) and seizure-outlasting alterations in the activity of putative GABAergic SNr neurons and in their response to pharmacological manipulation. Female Wistar rats were kindled via the basolateral amygdala by daily stimulation. In vivo extracellular single unit recordings of SNr neurons were performed in kindled rats 1 day after a generalized seizure in order to examine activity changes that outlast the kindled seizures. Sham-kindled and naive rats served as controls. We found a significant and seizure-outlasting increase of discharge rates within the posterior but not within the anterior SNr of kindled rats when compared to controls. Furthermore, kindling resulted in seizure-outlasting burst-like firing pattern of SNr neurons. The antiepileptic drug valproic acid (VPA; 100 mg/kg i.v.) significantly reduced SNr discharge rates in all animal groups. Interestingly, neurons located in the anterior SNr of kindled rats were significantly less depressed by VPA compared to the reduction obtained in naive controls. The present data disclose kindling induced functional plasticity within basal ganglia regions. The findings are relevant for a better understanding of the mechanisms underlying the seizure-gating function of the SNr and might provide new targets for rational therapeutic manipulations, which aim to establish a remote control of epileptic seizures.
Collapse
Affiliation(s)
- Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Bünteweg 17, D-30559 Hannover, Germany.
| | | | | | | |
Collapse
|
50
|
Devaud LL, Alele P. Differential effects of chronic ethanol administration and withdrawal on gamma-aminobutyric acid type A and NMDA receptor subunit proteins in male and female rat brain. Alcohol Clin Exp Res 2004; 28:957-65. [PMID: 15201639 DOI: 10.1097/01.alc.0000128225.83916.40] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Investigations have shown that chronic ethanol exposure results in selective alterations in levels of gamma-aminobutyric acid (GABA)A and NMDA receptor subunits. We previously reported significant sex differences in these chronic ethanol-induced adaptations. Because we have more recently found important sex differences in timing for the development of and recovery from ethanol dependence, we wanted to ascertain whether there were associations between overt expression of withdrawal and neuroadaptations at the level of GABAA and NMDA receptors. METHODS Western blot analysis was used to assay protein levels for several GABAA and NMDA receptor subunits in rat cerebral cortex and hippocampus by using subunit-selective antibodies. Rats were fed 6% ethanol in a liquid diet with pair-fed controls. Feeding, harvesting of tissue, and Western blot experiments were all conducted while maintaining the paired design. Tissue was harvested after 3 days of ethanol exposure, 9 days of ethanol exposure, or 3 days of ethanol withdrawal after 14 days of liquid diet administration. RESULTS We again found sex-, subunit-, and brain region-selective effects of ethanol administration and withdrawal for GABAA and NMDA receptors. There was a strong association between increased GABAA receptor alpha4 subunit levels and previously determined withdrawal-induced changes in seizure susceptibility, highlighted by the sex differences in ethanol exposure length required to cause withdrawal signs. In addition, results obtained after 9 days of ethanol administration were in general agreement with previous findings after 14 days of ethanol administration. CONCLUSIONS These data further support the suggestion that alterations in subunit assembly of GABAA and NMDA receptors may have some mechanistic role in neuroadaptations underlying ethanol dependence and withdrawal. Furthermore, significant sex differences in these adaptations suggest that multiple types of adaptations may be elicited, depending on innate differences in the actions/effects of ethanol.
Collapse
Affiliation(s)
- Leslie L Devaud
- Department of Pharmaceutical Sciences, Idaho State University, Pocatello, Idaho 83209-8334, USA.
| | | |
Collapse
|