Neonatal ischemic seizures: age and gender susceptibility to refractoriness

新生儿缺血性惊厥：年龄和性别对难治性癫痫的易感性

• 批准号: 8658589
• 负责人: Shilpa Dattatray Kadam
• 金额: $ 23.62万
• 依托单位: HUGO W. MOSER RES INST KENNEDY KRIEGER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8658589
• 关键词: Acids; Acute; Address; Adult; Affinity; Age; Agonist; Anticonvulsants; Antiepileptic Agents; Binding; Biological; Blood - brain barrier anatomy; Brain; Brain-Derived Neurotrophic Factor; Bumetanide; Cerebral Ischemia; Child; Chloride Ion; Chlorides; Combined Modality Therapy; Comorbidity; Data; Development; Diffusion Magnetic Resonance Imaging; Dose; Down-Regulation; Early treatment; Electroencephalography; Epilepsy; Event; Female; Funding; Future; Gender; Goals; Hour; Hypoxia; Immunohistochemistry; In Vitro; Infant; Injury; Intervention; Ischemia; Ischemic Stroke; KCC2 cotransporter; Life; Ligation; Magnetic Resonance Imaging; Modeling; Molecular Profiling; Mouse Strains; Mus; Neonatal; Neurons; Newborn Infant; Outcome; Pathway interactions; Pattern; Pharmaceutical Preparations; Pharmacotherapy; Phenobarbital; Phosphorylation; Phosphotransferases; Photons; Predisposition; Preparation; Protein Dephosphorylation; Protein Isoforms; Protocols documentation; Rattus; Refractory; Rodent Model; Role; Seizures; Severities; Stroke; Techniques; Testing; Tropomyosin; Up-Regulation; Western Blotting; age related; base; chloride-cotransporter potassium; clinical care; clinical practice; clomeleon; design; evidence based guidelines; gray matter; improved; in vivo; in vivo imaging; insight; interest; male; mouse model; novel; novel strategies; patient population; post stroke; postnatal; pre-clinical; prevent; public health relevance; pup; receptor; research study; response; sex; sexual dimorphism; small molecule; sodium-potassium-chloride cotransporter 1 protein; trend; white matter

DESCRIPTION (provided by applicant): The immature brain is susceptible to post-ischemic seizures. Current clinical practice includes empiric treatments with phenobarbital (PB) as first line for confirmed or suspected seizures in the newborn. This proposal will investigate the age and gender dependent differences in KCC2 expression and modulation following ischemic neonatal brains of CD1 mice. In preparation we have established the age-dependent increase in KCC2 expression and the age-dependent efficacy of first line anticonvulsant drug, phenobarbital on neonatal ischemic seizures in-vivo in P7, P10 and P12 pups. We have found phenobarbital to be inefficacious in suppressing ischemic seizures at P7 and significantly efficacious at P10 and P12 using quantitative video-EEG. Our data show a significant biological sex related difference both in the severity of post-ischemic seizures and in the efficacy of phenobarbital to suppress seizures at P7. The following hypotheses will be tested in the CD1 mouse model of neonatal stroke induced by unilateral common carotid ligation only (i.e., no global hypoxia): 1.Ischemic insults downregulate the acute and delay the sub-acute developmental expression profile of the adult-form electroneutral chloride cotransporter KCC2 (chloride-extruding K-Cl cotransporter) at P7 and P10; 2. Early blocking of KCC2 downregulation following ischemia may be a novel strategy to prevent emergence of refractory neonatal seizures. 3. Quantitative video-EEG of acute post-stroke events from P7 and P10 CD1 pups and their response to standard and novel anticonvulsants like PB and bumetanide (BTN; potent NKCC1 antagonist) will help predict the efficacy of combination therapies immediate versus early after blocking KCC2 downregulation following neonatal stroke. The added inefficacy of novel anticonvulsant BTN; a potent NKCC1 antagonist detected in our previously funded study by the EFA (2011) has highlighted the importance of the differential efficacy of BTN in different seizure models. Especially of interest are our preliminary findings that KCC2 is downregulated after ischemia in this model whereas NKCC1 expression remains stable with trends towards upregulation. Therefore the mechanism by which acute seizures are induced in immature brains and the specific effect that protocol has on enhancing or worsening chloride cotransporter function by phosphorylation or degradation of KCC2 may dictate the efficacy of anticonvulsants that depend on the chloride gradient for their anti-seizure effects. Post-ischemic response of preventing KCC2 downregulation to immediate treatment with combination therapy of phenobarbital and NKCC1 antagonist bumetanide will be investigated and compared to early treatment after the occurrence of ischemic seizures and evaluated for sexual dimorphism.

描述（由申请人提供）：未成熟的大脑易发生缺血后癫痫发作。目前的临床实践包括经验性治疗与苯巴比妥（PB）作为一线确认或疑似癫痫发作的新生儿。本研究将探讨KCC 2表达和调节的年龄和性别依赖性差异后，缺血新生儿脑的CD 1小鼠。在准备中，我们已经确定了KCC 2表达的年龄依赖性增加和一线抗惊厥药物苯巴比妥对P7、P10和P12幼仔体内新生儿缺血性癫痫发作的年龄依赖性疗效。我们已经发现苯巴比妥在P7抑制缺血性癫痫发作是无效的，而在P10和P12使用定量视频脑电图显着有效。我们的数据显示，在缺血后癫痫发作的严重程度和苯巴比妥抑制P7癫痫发作的疗效方面，存在显著的生物学性别相关差异。将在仅通过单侧颈总动脉结扎诱导的新生儿中风的CD 1小鼠模型中检验以下假设（即，无全身缺氧）：1.缺血损伤下调了成年型电中性氯离子转运体KCC 2（chloride-extruding K-Cl cotransporter）在P7和P10的急性表达谱，并延迟了亚急性发育表达谱;缺血后早期阻断KCC 2下调可能是预防难治性新生儿癫痫发作的一种新策略。3. P7和P10 CD 1幼仔急性卒中后事件的定量视频EEG及其对标准和新型抗惊厥药（如PB和布美他尼（BTN;强效NKCC 1拮抗剂））的反应将有助于预测新生儿卒中后阻断KCC 2下调后立即与早期联合治疗的疗效。新型抗惊厥药BTN（一种在我们先前由EFA（2011）资助的研究中检测到的强效NKCC 1拮抗剂）的无效性增加，突出了BTN在不同癫痫发作模型中差异疗效的重要性。特别令人感兴趣的是我们的初步发现，在该模型中，KCC 2在缺血后下调，而NKCC 1表达保持稳定，并有上调的趋势。因此，在未成熟的大脑中诱导急性癫痫发作的机制以及该方案通过磷酸化或降解KCC 2对增强或恶化氯协同转运蛋白功能的特定作用可能决定了依赖于氯梯度的抗癫痫作用的抗惊厥药的疗效。将研究预防KCC 2下调对苯巴比妥和NKCC 1拮抗剂布美他尼联合治疗的立即治疗的缺血后反应，并与缺血性癫痫发作发生后的早期治疗进行比较，并评价性二态性。