Pathobiology of Vascular Cognitive Impairment

描述(申请人提供)：血管认知障碍(VCI)是一种异质性疾病，是痴呆症的主要原因。小血管疾病患者的选择，皮质下缺血性血管性痴呆(SIVD)，提供了一个更同质的人群，这将促进临床试验。SIVD的病理研究显示血管周围基底板增厚，继发于高血压、糖尿病和先天性血管疾病的纤维素样坏死和透明蛋白沉着。缺血/缺氧导致基质降解金属蛋白酶(MMPs)的产生，作为损伤后炎症反应和组织重塑的一部分。我们发现，VCI患者脑组织中MMPs免疫反应阳性的星形胶质细胞和巨噬细胞/小胶质细胞，MMPs破坏血管周围的基质，打开血脑屏障(BBB)。此外，MMPs分解髓鞘，这可能导致SIVD中的血管脱髓鞘。最近，我们报道了VCI患者脑脊液中MMPs水平升高，而阿尔茨海默病(AD)患者脑脊液中MMPs水平升高。我们推测MMPs是由缺血/缺氧性脑细胞分泌的，参与了VCI的病理生物学过程。其具体目的是：1)建立基于多模式测试的SIVD评定量表，包括临床评估、磁共振成像(MRI)和多体素质子波谱(1H-MRS)、神经心理测试和脑脊液研究；2)通过将脑脊液和血液中的MMPs与白蛋白进行索引来确定脑脊液中MMPs的来源；3)用Patlak图解方法定性和定量地确定BBB与Gd-DTPA增强的关系，并将其与MMPs水平相关；4)将患者血清MMPs水平与SIVD评定量表结果进行盲法相关分析，并经长期随访验证。这些研究将确定蛋白酶介导的信息在进行性SIVD中的作用，并可能导致抑制蛋白水解酶的新疗法。

DESCRIPTION (provided by applicant): Vascular cognitive impairment (VCI) is a heterogeneous disorder that is a major cause of dementia. Selection of patients with small vessel disease, subcortical ischemic vascular dementia (SIVD), provides a more homogenous population that would facilitate clinical trials. Pathological studies in SIVD show thickening of the basal lamina around blood vessels with fibrinoid necrosis and hyalinosis secondary to hypertension, diabetes mellitus, and congenital vascular diseases. Ischemia/hypoxia leads to the production of matrix-degrading metalloproteinases (MMPs) as part of both an inflammatory response and tissue remodeling after injury. We have shown that brain tissues from patients with VCI immunostain for MMPs in reactive astrocytes and macrophage/microglia cells, MMPs disrupt the matrix around blood vessels and open the blood-brain barrier (BBB). In addition, MMPs break down myelin, which could contribute to the vascular demyelination seen in SIVD. Recently, we reported that increased levels of MMPs are found in the CSF of patients with VCI, but not in patients with Alzheimer's disease (AD). We hypothesize that MMPs are secreted by ischemic/hypoxic brain cells and contribute to the pathobiology of VCI. The specific aims are: 1) to develop a SIVD rating scale based on rnultimodal testing, including clinical evaluation, magnetic resonance imaging (MRI) and multivoxel proton spectroscopy (1H-MRS), neuropsychological testing, and CSF studies; 2) to identify the source of MMPs in the CSF by indexing the MMPs in the CSF and blood to albumin; 3} to determine the involvement of the BBB qualitatively with Gadolinium-DTPA enhancement and quantitatively with the Patlak Graphical Method and to correlate the opening with MMP levels; and 4) to correlate the levels of MMPs in a blinded fashion with the results of the SIVD rating scale that has been validated by long-term follow-up of the patients. These studies will determine the role of protease-mediated nflammation in the progressive form of SIVD, and could lead to novel treatments to suppress proteases.