Mechanisms of Seizure Genesis in Human Hypothalamic Hamartomas

人类下丘脑错构瘤癫痫发作的发生机制

基本信息

批准号：
7428968
负责人：
Jong Min Rho
金额：
$ 23.99万
依托单位：
ST. JOSEPH'S HOSPITAL AND MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-04-01 至 2010-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7428968
关键词：
Agonist Anatomy Bicuculline Brain Brain Neoplasms Bumetanide Calcium Calcium Channel Calcium Channel Blockers Cations Cells Cellular Membrane Child Childhood Chloride Ion Chlorides Clinical Complex Condition Data Development Disease Dyes Early Diagnosis Epilepsy Epileptogenesis Exhibits Gene Expression Goals Gramicidin Hamartoma Human Image Infant Institutes L-Type Calcium Channels Label Lesion Life Mediating Medical Membrane Membrane Potentials Modeling Molecular Morbidity - disease rate Muscimol Neurologic Neurons Newly Diagnosed Operative Surgical Procedures Output Pacemakers Patients Personal Satisfaction Population Positioning Attribute Precocious Puberty Prevalence Principal Investigator Public Health Receptor Activation Refractory Relative (related person)Research Proposals Resected Rest Reverse Transcriptase Polymerase Chain Reaction Seizures Series Slice Syndrome Techniques Tissues Translational Research United States base biocytin brain malformation calcium indicator experience fluorescence imaging fura-2-am hypothalamus hamartoma insight multidisciplinary nervous system disorder neurobehavioral novel prevent programs receptor research study response symporter voltage

项目摘要

DESCRIPTION (provided by applicant): The hypothalamic hamartoma (HH) is a rare congenital human brain malformation associated with gelastic (or laughing) seizures that are difficult to diagnosis early in life and are notoriously refractory to medical therapy. Despite increasing clinical recognition of this condition, the mechanisms of epileptogenesis are largely unknown. Importantly, seizures have previously been shown to originate from the hamartoma itself. At the Barrow Neurological Institute, we have treated over 100 patients with this condition over the past several years, constituting the largest single-center series ever; we are currently the only multidisciplinary program for HH management in the United States, and the most active HH program in the world. Thus, we are uniquely positioned to study the mechanisms of epileptogenesis in HH. The major goal of the proposed studies is to determine the mechanisms of seizure genesis in surgically resected HH tissue using a combination of cellular electrophysiological, fluorescence imaging, immunocytochemical and gene expression techniques. Our preliminary data demonstrate that HH tissue contains two distinct populations of neurons; small HH neurons exhibit intrinsic pacemaker-like activity, whereas large HH neurons are quiescent. We have demonstrated that a subpopulation of large HH neurons depolarize when perfused with the GABAA-receptor agonist muscimol. Based on these intriguing findings, we hypothesize that such GABAA-receptor mediated depolarization may be a consequence of decreased expression of the cation-chloride co-transporter KCC2 (relative to its cousin, NKCC1), and that such responses may contribute to seizure genesis. Specifically, we hypothesize that muscimol will increase intracellular calcium levels, an effect that can be blocked by the NKCC1 antagonist bumetanide. Further, we hypothesize that HH tissue will demonstrate decreased expression of KCC2 relative to NKCC1 using immunocytochemical and single-cell RT-PCR expression techniques. Although HH itself is uncommon with an estimated prevalence of 1 in 50,000-100,000 it is perhaps the best human model for subcortical epilepsy, and one of the most intriguing models for understanding the consequences of catastrophic epilepsy in childhood. As such, a detailed scientific understanding of this disorder has major ramifications for expediting translational research focused on the developmental epilepsies. PUBLIC HEALTH RELEVANCE: Epilepsy is a common neurological disorder that afflicts more than 3 million people in the United States alone, and many newly diagnosed patients are infants and children. There is a substantial need to understand how epilepsy develops in the pediatric population in order to develop newer, more effective treatments. This research proposal, while focused on a rare brain tumor that causes uncontrolled seizures, may provide novel insights into the mechanisms of seizure propagation and progression.

描述（由申请人提供）：下丘脑错构瘤（HH）是一种罕见的先天性人类大脑畸形，与痉挛（或大笑）癫痫发作相关，在生命早期很难诊断，并且众所周知难以接受药物治疗。尽管临床对这种情况的认识不断增加，但癫痫发生的机制在很大程度上仍不清楚。重要的是，此前已证明癫痫发作源于错构瘤本身。在巴罗神经病学研究所，我们在过去几年中治疗了 100 多名患有这种疾病的患者，构成了有史以来最大的单中心系列研究；我们目前是美国唯一的 HH 管理多学科项目，也是世界上最活跃的 HH 项目。因此，我们在研究 HH 癫痫发生机制方面具有独特的优势。拟议研究的主要目标是结合细胞电生理学、荧光成像、免疫细胞化学和基因表达技术来确定手术切除的 HH 组织中癫痫发作的机制。我们的初步数据表明 HH 组织包含两种不同的神经元群体：小的 HH 神经元表现出内在的起搏器样活动，而大的 HH 神经元则处于静止状态。我们已经证明，当用 GABAA 受体激动剂蝇蕈醇灌注时，大 HH 神经元的亚群会去极化。基于这些有趣的发现，我们假设这种 GABAA 受体介导的去极化可能是阳离子氯化物协同转运蛋白 KCC2（相对于其表亲 NKCC1）表达减少的结果，并且这种反应可能有助于癫痫发作的发生。具体来说，我们假设蝇蕈醇会增加细胞内钙水平，这种作用可以被 NKCC1 拮抗剂布美他尼阻断。此外，我们假设使用免疫细胞化学和单细胞 RT-PCR 表达技术，HH 组织将表现出 KCC2 相对于 NKCC1 表达降低。尽管 HH 本身并不常见，估计患病率为 50,000-100,000 分之一，但它可能是皮质下癫痫的最佳人体模型，也是了解儿童灾难性癫痫后果的最有趣的模型之一。因此，对这种疾病的详细科学理解对于加快针对发育性癫痫的转化研究具有重大影响。公共卫生相关性：癫痫是一种常见的神经系统疾病，仅在美国就有超过 300 万人受到影响，许多新诊断的患者是婴儿和儿童。为了开发更新、更有效的治疗方法，迫切需要了解癫痫在儿科人群中是如何发生的。这项研究提案虽然专注于一种导致癫痫失控的罕见脑肿瘤，但可能为癫痫传播和进展的机制提供新的见解。