Mechanism of cerebral vaculopathy and stroke in sickle cell disease

项目摘要 镰状细胞病(SCD)中的脑梗塞(卒中)是最戏剧性和改变生活的并发症之一。 导致身体受限和潜在的学习障碍。有证据表明，这种反常行为 白细胞-血管内皮细胞相互作用和血管重塑可能是病理生物学的重要因素 脑血管病变和卒中在SCD中的发病率。我们的总体目标是确定白细胞的潜在作用- 血管内皮细胞黏附和血管重塑在脑血管病病理生物学机制中的作用 SCD中的脑梗塞。识别在这些病理生物学机制中具有重要作用的分子可能 为预防中风提供了一种潜在的新型药物靶点。在我们的初步数据中，我们结合了两个光子 12月龄Townes人源化镰状细胞小鼠的激光扫描显微镜(TPLSM)和MRI/MRA观察。这 方法使我们能够进行体内成像，记录异常血管动力学的发生 测量(较高的红细胞流速和流量)、脑血管病变(血管扭曲)和镰刀形脑梗塞 细胞与对照小鼠进行比较。因为我们的结果是自发发展的，我们有能力 以确定潜在的因素，如白细胞-内皮细胞黏附和/或异常血管生成 可能是导致脑血管疾病和脑梗塞的原因。我们的假设是自发的 SCD脑血管病变的发生和扩散部分是由于白细胞-内皮细胞的异常 相互作用和血管重塑，由增加的内皮激活和促血管生成介导 周围的环境。基因或药物阻断白细胞-内皮细胞相互作用介质的镰状细胞小鼠 而血管生成将被产生和使用。这些小鼠将被前瞻性地与适当的 对照组采用TPLSM和MRI/MRA相结合的方法进行脑血管病变和脑梗塞的研究。 我们的具体目标是1)确定存在和/或 SCD的脑血管病变部位及脑梗塞的发生率、大小和数目。这将是 使我们能够进一步验证我们的模型，并有可能确定脑血管病变的发病年龄和 镰刀鼠脑梗塞。2)确定异常的白细胞-内皮细胞相互作用在发病中的作用 以及脑血管病变和脑梗塞的进展。这将使我们能够确定 已经有充分证据证明与已知的SCD血管并发症有关的黏附分子是 脑血管病变或脑梗塞的病理生物学因素，并可能成为中风的潜在靶点 预防。3)探讨血管内皮细胞生长因子受体2(VEGFR2)在血管内皮生长因子受体2(VEGFR2)中的作用 胎盘生长因子在SCD脑血管重构、血管病变及卒中中的作用在这里我们 将确定血管生成分子参与脑血管病变或脑梗塞的病理生物学 SCD。也是为了表明阻断这些分子的信号是否是预防中风的有用策略. 实现这些目标将极大地促进我们对SCD卒中机制的了解。

Project Abstract Cerebral infarction (stroke) in sickle cell disease (SCD) is one of the most dramatic and life altering complications of the disease, resulting in physical limitations and potential learning disabilities. Evidence suggests that aberrant leukocyte-endothelial interactions and vascular remodeling might be important contributors to the pathobiology of cerebral vasculopathy and stroke in SCD. Our overall goal is to define the potential role of leukocyte- endothelial adhesion and vascular remodeling in the pathobiological mechanism of cerebral vasculopathy and cerebral infarct in SCD. Identifying molecules with significant role in these pathobiological mechanisms could provide a potentially novel drug target for stroke prevention. In our preliminary data we combined two photon laser scanning microscopy (TPLSM) and MRI/MRA in 12 months old Townes humanized sickle cell mice. This approach enabled us to conduct in vivo imaging documenting the occurrence of abnormal vasodynamic measures (higher RBC velocity and flux), cerebral vasculopathy (vessel tortuosity), and cerebral infarcts in sickle cell compared to control mice. Because our outcomes were spontaneously developing, we are poised to be able to determine the potential factors such as leukocyte-endothelial adhesion and/or aberrant angiogenesis that could be driving the evolution of cerebral vasculopathy and infarction. Our hypothesis is that the spontaneous onset and propagation of cerebral vasculopathy in SCD is due in part to aberrant leukocyte-endothelial interaction and vascular remodeling, mediated by increased endothelial activation and a proangiogenic milieu. Sickle cell mice with genetic or pharmacologic blockade of mediators of leukocyte-endothelial interaction and angiogenesis will be generated and used. These mice will be prospectively imaged alongside appropriate controls using the combination of TPLSM and MRI/MRA for development of cerebral vasculopathy and infarcts. Our specific aims are 1) To determine the spatio-temporal relationship between the presence and/or location of cerebral vasculopathy and incidence, size and number of cerebral infarcts in SCD. This will enable us further validate our model and potentially establish the age of onset for cerebral vasculopathy and infarct in sickle mice. 2) To determine the role of aberrant leukocyte-endothelial interaction in the onset and progression of cerebral vasculopathy and cerebral infarcts. This will allow us to determine whether adhesion molecules already well documented to be associated with known SCD vascular complications are contributors to the pathobiology of cerebral vasculopathy or infarcts and could be potential targets of stroke prevention. 3) To determine the role of vascular endothelial growth factor receptor 2 (VEGFR2) and placenta growth factor (PlGF) in cerebral vascular remodeling, vasculopathy and stroke in SCD. Here we will determine the involvement of angiogenic molecules in the pathobiology of cerebral vasculopathy or infarct in SCD. Also to show whether blocking signaling from these molecules a useful strategy for stroke prevention. Achieving these aims will significantly advance our knowledge of the mechanisms of stroke in SCD.