GENETICS OF EARLY NEUROLOGICAL INSTABILITY AFTER ISCHEMIC STROKE (GENISIS)

中风是全世界第二大死亡原因，也是导致长期残疾的主要原因。 缺血性中风是最常见的亚型，是由脑中动脉闭塞引起的， 突然出现神经功能缺损。在中风发作后的最初几个小时内，神经功能障碍可能会 非常不稳定，许多患者病情好转，而另一些患者病情恶化。这些早期的变化 对长期结果有重大影响。事实上，最初24小时内神经功能缺损的变化， 90天改良兰金量表（最广泛接受的卒中结局指标）方差的40% 组织型纤溶酶原激活剂（tPA）治疗的患者。在我的初步分析中，发现 基线临床因素对前24个月内神经功能缺损的变化几乎没有影响。 而遗传因素似乎占50%以上。考虑到遗传学会影响 早期神经系统变化的差异，这是我的中心假设，遗传学发挥了重要作用， 确定患有急性缺血性中风（AIS）的患者经历的早期结果。 作为一名接受过奖学金培训的急诊医生，我长期从事神经病学急诊， 我们的目标是开发一个独立的研究项目，调查遗传对急性 神经系统紧急情况，以改善患者预后。为了实现这一目标，我制定了 在奖励期间将实现两个短期目标：1）在技术上精通 遗传/基因组分析和研究方法; 2）更熟悉细胞 以及AIS后脑和神经血管损伤的分子机制。为了 为了实现这些目标，我组建了一个由导师、顾问和合作者组成的多学科团队。来 在过去的几年里，我一直与我的主要导师李金茂博士（ 神经科脑血管疾病和神经重症监护科）和我的第二位导师博士。 卡洛斯Cruchaga（人类遗传学家，具有复杂遗传分析的专业知识），以检查可能的遗传 对急性缺血性卒中后早期神经功能预后的影响。他们都有着良好的记录 指导初级调查员，并为我的指导带来免费的背景和专业知识， 职业发展。 在Jin-Moo Lee博士和卡洛斯·克鲁查加博士的指导下，我将参加结构化的课程， 高级培训和独立学习，精通以患者为导向的研究，遗传分析， 和研究方法。为了捕捉AIS后的早期神经变化，我们开发了一种新的 定量内表型，称为Δ NIHSS 24 h，其是NIH卒中量表变化的量度 基线（发作后<6小时）和24小时之间的NIHSS评分。使用接受治疗的AIS患者队列 IV tPA，将由来自国际多中心联盟的3，000名表型受试者组成 并代表了世界上最大的与遗传学相关的早期中风结果数据集，我将探索 如下： 目的1：进行全基因组关联研究（GWAS），检查早期神经系统变化 （Δ NIHSS 24h）。使用前3，000例tPA治疗的AIS患者（发现队列，估计招募 2016年9月），将进行常见和罕见编码变体的GWAS以发现单个变体， 与Δ NIHSS 24 h相关的基因和途径。另外3，000例tPA治疗患者（复制 队列）将在2019年9月前累积，并用于复制初始Discovery队列的结果。 目的2：使用极端表型采样，具有大效应量的低频功能变体 AIS后早期神经功能恶化（目标2a）或改善（目标2b）。我们会挑选病人 最极端的Δ NIHSS 24 h，代表恶化或改善最大的那些，以及 Δ NIHSS 24 h变化不大。在每个极端中的顶级命中的复制将是 在整个队列中进行基于基因的测序和分析。在病情恶化的病人中， 我们将确定哪些遗传变异与出血性转化相关，哪些不相关。 这个研究计划反映了我在紧急情况下的多学科培训和职业发展 医学神经系统急症和遗传学这是一个长期的目标， 这项研究提案中提出的将揭示参与急性脑损伤的重要变异、基因和途径。 缺血，可能导致诊断和治疗目标，以改善中风后的结果。

Stroke is the 2nd leading cause of death throughout the world, and the leading cause of long-term disability. Ischemic stroke, the most common subtype, is caused by occlusion of an artery in the brain, resulting in the abrupt development of neurological deficits. In the first hours after stroke onset, neurological deficits can be highly unstable, with many patients improving while others deteriorate. These early changes have a major impact on long-term outcome. In fact, changes in neurologic deficits during the first 24 hours account for 40% of the variance of the 90-day modified Rankin Scale (the most widely accepted stroke outcome measure) in patients treated with tissue plasminogen activator (tPA). In my preliminary analyses, it was discovered that baseline clinical factors account for very little of the variation seen in neurologic deficits during the first 24 hours while genetic factors appear to account for over 50%. Given the finding that genetics influence the variance of early neurologic changes, it is my central hypothesis that genetics play a significant role in determining the early outcomes experienced by patients suffering from acute ischemic stroke (AIS). As a fellowship-trained emergency physician subspecializing in neurologic emergencies, my long term goal is to develop an independent research program to investigate genetic influences on acute neurological emergencies to improve patient outcomes. In order to achieve this goal, I have developed two short term goals that will be achieved during the award period: 1) to become technically proficient in genetic/genomic analysis and research methodology and 2) to develop greater familiarity with cellular and molecular mechanisms involved with brain and neurovascular injury following AIS. In order to achieve these goals, I have crafted a multidisciplinary team of mentors, advisors and collaborators. Over the past several years, I have been working closely with my primary mentor, Dr. Jin-Moo Lee (Director of the Cerebrovascular Disease and Neurointensive Care Sections in Neurology) and my secondary mentor Dr. Carlos Cruchaga (a human geneticist with expertise in complex genetic analyses), to examine possible genetic influences on the early neurologic outcomes after acute ischemic stroke. They both have a strong track record of mentoring junior investigators and bring complimentary backgrounds and expertise to my mentoring and career development. Under the guidance of Drs. Jin-Moo Lee and Carlos Cruchaga, I will engage in structured coursework, advanced training and independent study to become proficient in patient-oriented research, genetic analysis, and research methodology. To capture early neurological change following AIS, we have developed a novel quantitative endophenotype, termed ΔNIHSS24h, which is a measure of the change in NIH stroke scale (NIHSS) score between baseline (<6 hours after onset) and 24 hours. Using a cohort of AIS patients treated with IV tPA that will consist of 3,000 phenotyped subjects drawn from an international multicenter consortium and representing the largest such dataset of early stroke outcomes linked to genetics in the world, I will explore the following: Aim 1: To perform genome-wide association studies (GWAS), examining early neurological change (ΔNIHSS24h) after AIS. Using the first 3,000 tPA-treated AIS patients (Discovery cohort, estimated accrual September, 2016), GWAS of common & rare coding variants will be performed to discover single variants, genes, and pathways associated with ΔNIHSS24h. An additional 3,000 tPA-treated patients (Replication Cohort) will be accrued by September 2019, and used to replicate findings from the initial Discovery cohort. Aim 2: To use extreme phenotype sampling with low frequency functional variants of large effect size for early neurological deterioration (Aim 2a) or improvement (Aim 2b) after AIS. We will select patients with the most extremes of ΔNIHSS24h, representing those with greatest deterioration or improvement, and compare to matched controls with little change in ΔNIHSS24h. Replication of the top hits in each extreme will be performed in the overall cohort with gene-based sequencing and analysis. Of those patients who deteriorate, we will determine which genetic variants associate with hemorrhagic transformation and which do not. This research plan reflects my multidisciplinary training and career development in emergency medicine, neurologic emergencies, and genetics. It is a long-term objective that the unbiased approach presented in this research proposal will reveal important variants, genes and pathways involved in acute brain ischemia, possibly leading to both diagnostic and therapeutic targets to improve outcomes following stroke.