Investigation into hMSC-derived therapy in ischemic stroke at high field MRimaging and spectroscopy

项目摘要 在美国，中风引起的神经损伤是导致长期残疾的主要原因， 每年有超过795，000人患有中风，其中约17%导致死亡。不幸的是， 只有一种药物，组织纤溶酶原激活剂，具有狭窄的4.5小时治疗窗， 只有5%的患者受益。因此，很明显，需要一种有效的治疗方法来最大限度地减少短期和长期的疼痛。 间充质干细胞（hMSC）在胚胎干细胞移植中表现出治疗作用。 神经损伤后的组织恢复。本研究评价了动脉内注射 在临床相关治疗窗（4-6小时）内给予hMSC衍生治疗，靶向急性 使用缺血性中风大鼠模型观察神经变性。组织恢复，特别是脑钠波动 以及由诱导的短暂性缺血引起的相应代谢物变化， 利用创新的磁共振成像和光谱（MRI/S）采集技术， 领域恢复的MR评估将与行为和免疫组织化学分析相关。 具体地说，这项工作提出了在2D培养下研究hMSC预处理的影响， 缺氧或从3D聚集体解离的细胞，以建立3D预处理在细胞生长过程中的作用。 扩大治疗效果。预处理方法旨在增强细胞的稳健性和分泌性。 提高基于hMSC的脑缺血治疗效果的能力。这种预处理可以获得 对移植细胞以及细胞来源的外泌体的益处，提供了两种基于细胞的方法， 缺血治疗，这将有助于确定和优化的主要机制，hMSC的影响，无论是通过 直接细胞相互作用或旁分泌效应。作为一种天然的延伸，来源于hMSC或神经干细胞的外泌体可以被称为外泌体。 将评价祖细胞（NPC）在分泌治疗对组织恢复的作用。到 为了评估归巢，基于细胞的疗法将用氧化铁MR造影剂在细胞内标记。 此外，正在提出一种利用19 F标记追踪外来体的创新和新颖的方法。 由多官能氟化聚合物组成的造影剂，以可视化和定量外泌体递送， 缺血性梗塞我们的目标是确定hMSC在缺血区域的存在是否是必需的， 单独递送细胞分泌物局部地或通过募集内源性再生作用来改善结果。

Project Summary Neurological damage resulting from stroke is a leading cause of long-term disability in the United States with more than 795,000 people suffering a stroke annually, of which approximately 17% result in death. Unfortunately, only one drug, tissue plasminogen activator, is clinically effective with a narrow 4.5-h therapeutic window that benefits only 5% of patients. Thus, it is evident that an effective therapy is needed to minimize short- and long- term damages, and human mesenchymal stem cells (hMSC) have been shown to exhibit therapeutic effects on tissue recovery following neurological damage. This study evaluates the therapeutic effects of intra-arterially administered hMSC-derived therapy in the clinically relevant treatment window (4-6 h) targeting acute neurodegeneration using an ischemic stroke rat model. Tissue recovery, notably cerebral sodium fluctuations and corresponding metabolite changes resulting from induced transient ischemia, will be mapped temporally utilizing innovative magnetic resonance imaging and spectroscopy (MRI/S) acquisition techniques at ultra-high field. MR assessment of recovery will be correlated to behavioral and immunohistochemical analysis. Specifically, this work proposes investigation into the effects of hMSC preconditioning under 2D culture with hypoxia or dissociated cells from 3D aggregates to establish the role of 3D pre-conditioning during cellular expansion on therapeutic efficacy. Preconditioning methods aim to enhance cell robustness and secretory capacity to improve the efficacy of hMSC-based treatment for cerebral ischemia. Such preconditioning can reap benefits for transplanted cells as well as cell-derived exosomes, providing two cellular-based approaches to ischemic therapy that will help to identify and optimize the primary mechanism of hMSC impact—whether by direct cell interaction or paracrine effect. As a natural extension, exosomes derived either from hMSC or neural progenitor cells (NPC) will be evaluated for their role in secretory therapeutic effects on tissue recovery. To evaluate homing, cell-based therapies will be labeled intracellularly with an iron oxide MR contrast agent. Additionally, an innovative and novel method for tracking exosomes is being proposed utilizing a 19F labeling contrast agent composed of multifunctional fluorinated polymers to visualize and quantify exosome delivery to the ischemic infarct. Our goal is to determine if the presence of hMSC in an ischemic region is required or if delivery of cell secretions alone improves outcomes, locally or by recruiting endogenous regenerative action.