Reversing Inflammatory Macrophage Activation as Treatment for Neonatal Intraventricular Hemorrhage and Hydrocephalus

新生儿脑室内出血(IVH)起源于生发基质发育不良的部位 大脑侧脑室附近的细胞快速分裂。静脉内出血导致出血后 脑积水(PHH)。在新生儿IVH发生的同一时间范围内，新生儿的大脑也迅速 产生髓鞘形成所需的细胞。少突胶质细胞，即大脑的髓鞘形成细胞，是从 来自少突胶质前体细胞(OPC)。OPC是脆弱的细胞-对许多因素非常敏感 存在于多种神经系统疾病中，如兴奋性毒性、炎性细胞因子和氧化 压力。在广泛的神经系统疾病中，神经炎症会导致OPC丢失和OPC失败 髓鞘形成。浸润性脑巨噬细胞与多种形式的新生儿脑损伤有关。巨噬细胞 在中枢神经系统损伤和疾病中被许多不同的刺激激活，包括释放到 脑室空间。了解IVH后巨噬细胞的作用对于改善预后至关重要，因为 巨噬细胞激活在其他形式的新生儿脑损伤中介导白质损伤。 阿奇霉素是一种常用的抗生素，对新生儿是安全的。除了它的抗生素 性质，阿奇霉素也是抗炎的，并将巨噬细胞的激活转变为抗炎 实际上促进组织恢复而不是损伤的表型。阿奇霉素已被用于各种 抗炎应用，包括改善组织保护的脊髓损伤的临床前工作 和神经功能。重要的是，阿奇霉素已经在新生儿身上进行了严格的临床试验。 治疗炎症引起的肺损伤。本研究将从药理上阻断巨噬细胞的侵袭。 IVH/PHH及阿奇霉素对巨噬细胞诱导的OPC损伤的保护作用 新生儿IVH。我将使用体内和体外实验相结合的方法来检测巨噬细胞的激活， 阿奇霉素治疗前后OPC死亡和髓鞘形成。我的活体工作将允许我们使用 神经行为结果评估阿奇霉素的疗效，而我的体外模型将允许深入研究 巨噬细胞-OPC相互作用的机制研究。该项目将支持米勒博士在以下方面的培训 神经炎症和神经治疗学。如果成功，该项目将为临床研究铺平道路。 阿奇霉素改善新生儿IVH后的神经预后。

Neonatal Intraventricular hemorrhage (IVH) originates from the underdeveloped germinal matrix, a site of cell rapid cell division adjacent to the lateral ventricles of the brain. IVH leads to post-hemorrhagic hydrocephalus (PHH). Within the same time frame that neonatal IVH occurs, the neonatal brain is also rapidly producing the cells needed for myelination. Oligodendrocytes, the myelin-forming cells of the brain, are derived from oligodendrocyte progenitor cells (OPCs). OPCs are fragile cells - exquisitely sensitive to many factors that are present across multiple neurological diseases such as excitotoxicity, inflammatory cytokines, and oxidative stress. Across a wide spectrum of neurological diseases, neuroinflammation causes OPC loss and failure of myelination. Infiltrating brain macrophages are implicated in many forms of neonatal brain injury. Macrophages are activated by many different stimuli in CNS injury and disease, including blood products released into the ventricular space. Understanding the role of macrophages after IVH is critical to improving outcomes, as macrophage activation mediates white matter injury in other forms of neonatal brain injury. Azithromycin is a commonly prescribed antibiotic that is safe in neonates. Besides its antibiotic properties, azithromycin is also anti-inflammatory and shifts macrophage activation into an anti-inflammatory phenotype that actually promotes tissue recovery rather than injury. Azithromycin has been used in a variety of anti-inflammatory applications including preclinical work in spinal cord injury where it improves tissue sparing and neurological function. Importantly, azithromycin has already undergone rigorous clinical trials in neonates for inflammation-induced lung injury. This study will pharmacologically block infiltrating macrophages in IVH/PHH and test azithromycin’s ability to protect OPCs from macrophage-induced injury in a rat model of neonatal IVH. I will use a combination of in vivo and in vitro experiments to examine macrophage activation, OPC death and myelination with and without azithromycin treatment. My in vivo work will allow us to use neurobehavioral outcomes to assess the efficacy of azithromycin while my in vitro model will allow for in-depth mechanistic studies of macrophage-OPC interaction. This project will support Dr. Miller’s training in studies of neuroinflammation and neurotherapeutics. If successful, this project will pave the way for clinical studies of azithromycin for improving neurological outcome after neonatal IVH.