Progressive seizure-induced cardiorespiratory dysfunction in a novel mutant rat model of seizure disorder

项目摘要 全球有超过5000万人患有癫痫。目前的抗癫痫药物(AEDs)无法预防 这些患者中约30%的人癫痫发作，导致无法控制或难治性癫痫。不幸的是，这些病人 极有可能导致癫痫猝死(SUDEP)，这是#年的主要死亡原因 这群人。基于具有里程碑意义的SUDEP研究，目前的假设是反复癫痫发作会导致极端 通过对调节生命的神经网络的负面影响而导致心肺抑制和/或心力衰竭 功能，如呼吸、心率和血压。然而，目前仍不清楚反复发作的原因 从根本上影响脑干内的心肺控制网络，以及通过什么机制 SUDEP中的重要系统出现故障。在这里，我们的目的是描述反复发作的病理生理后果 一种钾通道基因已知突变的新型大鼠模型(kcnj16；SSkcnj16-/-鼠)的癫痫发作 一种温和强度的特定声音容易且可重复地引起全身强直阵挛发作 (GTCSs)。声诱导SSkcnj16-/-大鼠的GTCS导致类似于所描述的刻板印象的事件模式 在癫痫患者中，包括发作后全身脑电抑制和呼吸暂停，其次是呼吸频率 (RR)和心率(HR)抑制。反复发作(每天1次，最多10天)导致：1)癫痫发作后 发作抑制RR和HR，降低对低氧和高碳酸血症的呼吸反应，以及 这些老鼠中约33%的人意外死亡。重复暴露对SSkcnj16-/-大鼠脑干组织的影响 癫痫发作显示炎症和腺苷调节失调(ADO)呈时间依赖性增加。 和5-羟色胺(5-羟色胺)--两个强大的心肺神经网络调节器。最后，从药理上讲 加用5-羟色胺(SSRI)(氟西汀)可防止反复发作的进行性抑制发作后RR 癫痫发作。在这里，我们将检验我们的中心假设，即反复癫痫发作会导致进行性脑干 由神经炎症引发的病理，由ADO和5-羟色胺功能障碍介导 SUDEP的心肺功能抑制和/或衰竭。利用这一新突变大鼠进行的拟议研究 模型将提供：1)进行性病理生理反应的综合表征 反复听源性癫痫发作和导致意外死亡的事件顺序(目标1)，2)已查明 危重心肺疾病中炎症和/或神经调节通路功能障碍的机制 反复癫痫发作对脑干核团的负面影响(目标2)，以及3)对我们的 阻断神经炎症或调节ADO或5-羟色胺系统活性的假说 反复发作(目标3)。我们将利用成熟和尖端技术的组合来提供 对病理生理后果的前所未有的分子、细胞和系统水平的洞察 在生命控制系统上反复发作，以确定新的治疗干预目标 预防或减轻人类癫痫患者的SUDEP风险。

Project Summary More than 50 million people suffer from epilepsy globally. Current anti-epileptic drugs (AEDs) cannot prevent seizures in ~30% of these patients, leading to uncontrolled or refractory epilepsy. Unfortunately, these patients are at extreme risk of Sudden Unexpected Death in Epilepsy (SUDEP), which is the leading cause of death in this cohort. Based on landmark SUDEP studies, the current hypothesis is that recurrent seizures induce extreme cardiorespiratory suppression and/or failure through negative effects on the neural networks that regulate vital functions such as breathing, heart rate and blood pressure. However, it remains unclear how repeated seizures fundamentally affect cardiorespiratory control networks within the brainstem, and by what mechanisms these vital systems fail in SUDEP. Here we aim to characterize the pathophysiologic consequences of repeated seizures in a novel rat model with a known mutation in a potassium channel gene (kcnj16; SSkcnj16-/- rats), in which a specific sound of mild intensity readily and reproducibly causes generalized tonic-clonic seizures (GTCSs). Sound-induced GTCSs in SSkcnj16-/- rats led to a stereotypic pattern of events similar to that described in epilepsy patients, including post-ictal generalized EEG suppression and apnea, followed by respiratory rate (RR) and heart rate (HR) suppression. Repeated seizures (1/day for up to 10 days) led to: 1) augmented post- ictal suppression of RR and HR, reduced ventilatory responses to hypoxic and hypercapnic challenges, and unexpected mortality in ~33% of these rats. Brainstem tissue analyses of SSkcnj16-/- rats exposed to repeated seizures showed evidence of time-dependent increases in inflammation and dysregulation of adenosine (ADO) and serotonin (5-HT) – two powerful modulators of cardiorespiratory neural networks. Finally, pharmacologically augmenting 5-HT with an SSRI (fluoxetine) prevented the progressive suppression of post-ictal RR with repeated seizures. Herein we will test our central hypothesis that repeated seizures cause a progressive brainstem pathology initiated by neuroinflammation and mediated by ADO and 5-HT dysfunction leading to cardiorespiratory suppression and/or failure in SUDEP. The proposed studies utilizing this novel mutant rat model will provide: 1) a comprehensive characterization of the progressive pathophysiological responses to repeated audiogenic seizures, and sequence of events leading to unexpected death (Aim 1), 2) identified mechanisms of dysfunction in inflammatory and/or neuromodulatory pathways within critical cardiorespiratory brainstem nuclei negatively affected by repeated seizures (Aim 2), and 3) interventions that functionally test our hypothesis by blocking neuroinflammation or modulating ADO or 5-HT system activity on the backdrop of repeated seizures (Aim 3). We will utilize a combination of established and cutting-edge technologies to provide unprecedented molecular, cellular and systems-level insights into the pathophysiological consequences repeated seizures on vital control systems in order to identify novel targets for therapeutic interventions aimed at preventing or mitigating the risk of SUDEP in human epilepsy patients.