Is There a Link Between Alzheimer's and Atheroclerosis

描述(申请人提供)：阿尔茨海默病(AD)是一种神经退行性疾病，影响超过400万美国人。我们是第一个证明阿尔茨海默病患者脑血管释放神经毒性蛋白的人。然而，导致这种血管功能障碍的因素尚不清楚。我们的假设是，参与动脉粥样硬化发病机制的危险因素也与阿尔茨海默病血管介导的神经细胞死亡的发展有因果联系。我们的研究是及时和重要的，因为越来越多的证据表明动脉粥样硬化和阿尔茨海默病之间存在联系。目的：探讨全身性氧化应激或高脂血症对载脂蛋白E转基因小鼠血管凝血酶释放、血管介导的神经毒性及认知功能的影响。从apoE基因敲除或表达人E3或E4的转基因小鼠分离的脑血管被用来评估apoE亚型对凝血酶血管表达的作用。饮食诱导的高同型半胱氨酸血症和高脂血症分别用于评估氧化应激和血脂在血管凝血酶释放和血管介导的神经毒性中的作用。此外，这些转基因小鼠还被用来评估氧化剂和脂质应激对学习和记忆损害的可能的apoE亚型特异性影响。目的：确定参与动脉粥样硬化发病的危险因素是否也与阿尔茨海默病血管介导的神经细胞死亡有关。分离AD患者和非痴呆患者的脑微血管，分析凝血酶和其他可能的神经毒性蛋白的水平和/或活性，包括基质金属蛋白酶(MMPs)、炎性细胞因子和趋化因子以及内皮素-L。蛋白水平用ELISA法和Western blots法测定，mRNA水平用Northern blots法和RT-PCR法测定。载脂蛋白E亚型在调节这些蛋白中的作用是通过比较从不同载脂蛋白E基因型患者分离的微血管来确定的。在体外向分离的脑微血管中加入氧或脂分子，分别评估氧化应激和脂类对凝血酶、基质金属蛋白酶、炎性蛋白和内皮素释放的影响-L。在暴露于这些蛋白质的培养神经元细胞中检测到了细胞的凋亡和坏死。 这些结果将首次确定阿尔茨海默病心血管风险因素与血管介导的神经细胞死亡之间的机械性级联反应，并确定治疗干预的新靶点。

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is a neurodegenerative disease that affects over 4 million Americans. We are the first to demonstrate that brain blood vessels release neurotoxic proteins in Alzheimer's disease. However, the factors that cause this vessel dysfunction are not known. It is our hypothesis that risk factors involved in the pathogenesis of atherosclerosis are also causally linked to the development of vascular-mediated neuronal cell death in Alzheimer's disease. Our studies are timely and important as increasing evidence points to a link between atherosclerosis and Alzheimer's disease. Aim 1: To determine the effects of systemic oxidant stress or hyperlipidemia on vascular thrombin release, vascular-mediated neurotoxicity and on the cognitive performance of apoE transgenic mice. Brain blood vessels isolated from apoE knockout or transgenic mice expressing human E3 or E4 are used to assess the role of apoE isoforms on vascular expression of thrombin. Diet-induced hyperhomocystinemia and hyperlipidemia, are used to assess the role of oxidant stress and lipids, respectively, on vascular thrombin release and vascular-mediated neurotoxicity. Also, these transgenic mice are utilized to evaluate possible apoE isoform-specific effects of oxidant and lipid stress on impairments in learning and memory. Aim 2: To determine if risk factors involved in the pathogenesis of atherosclerosis are also causally linked to the development of vascular-mediated neuronal cell death in Alzheimer's disease. Brain microvessels are isolated from AD patients and non-demented patients and analyzed for levels and/or activity of thrombin and other possible neurotoxic proteins, including, matrix metalloproteinases (MMPs), inflammatory cytokines and chemokines, and endothelin-l. Protein levels are determined by ELISA and Western blots and Mrna levels assessed by Northern blots and RT-PCR. The role that apoE isoforms play in regulating these proteins is determined by comparing microvessels isolated from patients with different APOE genotypes. In vitro addition of oxygen species or lipid molecules to isolated brain microvessels is used to assess the effects of oxidative stress and lipids, respectively, on release of thrombin, MMPs, inflammatory proteins, and endothelin-l. Apoptosis and necrosis are measured in cultured neuronal cells exposed to these proteins. These results would, for the first time, identify a mechanistic cascade linking cardiovascular risk factors to vascular-mediated neuronal cell death in Alzheimer's disease and identify novel targets for therapeutic intervention.