Hemorrhagic transformation associated with delayed reperfusion in perinatal and childhood ischemic stroke: brain maturation-dependent role of leukocytes

摘要 大脑动脉阻塞后的脑微循环再灌注可能具有双重作用- 如果再灌流是早期的神经保护，但如果再灌流会出现不良事件和增加神经功能障碍 被推迟了。机械血栓切除术使成人中风的护理发生了革命性变化，并已被证实对 多个随机临床试验，时间窗口从4.5小时逐渐增加到24小时或更长时间。在……里面 动脉缺血性卒中的儿童，回顾性病例系列提示安全性和可能的益处 然而，血栓切除术的选择偏差和缺乏未经治疗的对照结果引起了人们的关注，即 儿童可以安全地受益于血管内血栓切除术。缺乏以科学为基础的证据 当儿童缺血性中风后血栓清除是安全的时候。围产期动脉缺血性中风(PAIS) 和儿童动脉缺血性中风(CAIS)是发病率和复发率不同的疾病和 中枢神经系统成熟过程中年龄差异导致的多种非重叠损伤机制 和免疫系统。在这项试探性的R21拨款中，我们将开始填补这一知识空白 使用实验性的PAI和CAIS模型清除血栓是安全的。 中心假说：单核细胞-小胶质细胞-中性粒细胞相互作用调节不同的时间窗 PAI和CAI晚期再通的不良反应。 大鼠大脑中动脉长时间短暂性闭塞后的“晚期再灌注”模型 新生儿和青少年男性和女性，我们将确认再灌注并检查出血的程度 转化与血脑屏障(BBB)完整性、水肿和短期组织学结果的关系。 每个年龄组的炎症反应的大小将由累积的 血液和脑中的炎性细胞因子/趋化因子(复合体)，出血标志物(d-二聚体 以及浸润性中性粒细胞和单核细胞的表型(流式细胞术)(目标1)。到时候我们会的 检查CCR2或CX3CR1信号的遗传中断是否影响出血的程度 晚期再灌注后的转化、血脑屏障渗漏以及短期组织学和功能结果 在P9和P21雌雄小鼠中，并测定脑成熟对浸润性脑脊髓炎的表型的影响 白细胞和激活的小胶质细胞/巨噬细胞(流式细胞术、免疫荧光)和 神经炎症(细胞因子复合体)(目标2)。拟议的研究将作为以下方面的原则证明 确定出生后脑成熟如何影响晚期出血性转化的易感性 血管再通和帮助确定婴儿延迟再通的安全指南 卒中。

Abstract Reperfusion of cerebral microcirculation following cerebral artery blockage can have dual roles — neuroprotection if reperfusion is early but adverse events and increased neurological disability if reperfusion is delayed. Mechanical thrombectomy has revolutionized care in adult stroke and is of proven benefit in multiple randomized clinical trials with time windows gradually increasing from 4.5 to 24 or more hours. In children with arterial ischemic stroke, retrospective case series suggest safety and possible benefit of thrombectomy, however selection bias and a lack of non-treated control outcomes raise concerns on whether children can safely benefit from endovascular thrombectomy. There is lack of science-based evidence on when it is safe to remove thrombus after pediatric ischemic stroke. Perinatal arterial ischemic stroke (PAIS) and childhood arterial ischemic stroke (CAIS) are diseases with distinct occurrence and recurrence rates and many non-overlapping injury mechanisms due to the age-related differences in the maturation of the CNS and the immune system. In this exploratory R21 grant we will begin filling the knowledge gap of when it is safe to remove thrombus using experimental PAIS and CAIS models. Central Hypothesis: Monocyte-microglia-neutrophil interactions mediate distinct time windows for adverse effects of late recanalization in PAIS and CAIS. In models of ‘late reperfusion’ following long transient middle cerebral artery occlusion (tMCAO) in neonatal and juvenile males and females we will confirm reperfusion and examine the extent of hemorrhagic transformation in relation to blood-brain barrier (BBB) integrity, edema and short-term histological outcomes. The magnitude of the inflammatory response in each age group will be determined by accumulation of inflammatory cytokines/chemokines (multiplex) in the blood and in the brain, hemorrhagic markers (d-dimer assay) and the phenotypes of infiltrated neutrophils and monocytes (flow cytometry) (Aim 1). We will then examine whether genetic disruption of CCR2 or Cx3CR1 signaling affects the magnitude of hemorrhagic transformation, BBB leakage, and short-term histological and functional outcomes following late reperfusion in P9 and P21 mice of both sexes, and determine the role of brain maturation on the phenotypes of infiltrated leukocytes and activated microglia/macrophages (flow cytometry, immunofluorescence) and neuroinflammation (cytokine multiplex) (Aim 2). The proposed studies will serve as proof-of-principle in defining how postnatal brain maturation affects the susceptibility to hemorrhagic transformation after late recanalization and help define safety guidance for delayed recanalization in infants of children who suffer stroke.