ALZHEIMER'S AMYLOID PLAQUE PERSISTENCE IN VIVO

阿尔茨海默病（AD）是一种退行性脑部疾病，临床表现为记忆力、认知、推理、判断和情绪稳定性的进行性丧失，逐渐导致严重的精神退化，最终导致死亡。阿尔茨海默病的特征是含有β -淀粉样蛋白（Abeta）的不溶性纤维淀粉样蛋白沉积在大脑中，以细胞外淀粉样斑块或在脑实质的血管壁上积聚。大脑中β -淀粉样蛋白的持续存在被认为在AD的发病机制中发挥核心作用，导致神经元丢失和记忆功能障碍。在过去的几年里，我们的研究已经确定了其他额外的因素，如特定的硫酸肝素蛋白聚糖（即perlecan），对于阿尔茨海默病大脑中“纤维状”β沉积的形成和持续是必要的。利用纯化的粗蛋白建立了一个一致的啮齿类动物模型，用于大脑中β淀粉样蛋白的快速沉积和持久性。1或2周向海马内注射Abeta + perlecan可导致80只动物中的80只（100%）出现嗜血性淀粉样蛋白沉积，而单独注射Abeta的70只动物中有41只（58.5%）出现嗜血性淀粉样蛋白沉积。Perlecan有助于脑内β -淀粉样蛋白的长期持续和脑血管淀粉样蛋白沉积的形成，而在β -淀粉样蛋白输注后未观察到。我们现在通过实施新的专有方案，在体外诱导马尔氏交叉嗜嗜性淀粉样斑块样沉积物的形成，显著地推进了该动物模型，该沉积物在形态和超微结构上与来自AD大脑的淀粉样斑块核心相似。新的动物建模方法可用于快速体内鉴定潜在的抗淀粉样斑块治疗方法，这些治疗方法针对淀粉样斑块a)沉积，b)持续存在和/或c)在大脑中的溶解和清除。本I期计划的主要目标是：1)确定蛋白聚糖/ gag在淀粉样斑块形成中的作用；2)确定“淀粉样斑块”、“纤维”Abeta持久性和脑内脑血管淀粉样蛋白沉积的解剖和分子后果。所描述的研究将进一步建立一致的Abeta淀粉样斑块沉积和持久性动物模型，并将允许（在II期建议中）快速筛选新的潜在治疗候选药物来治疗AD中的Abeta斑块淀粉样变性。拟议的商业应用：阿尔茨海默病（AD）目前影响着4-5百万美国人，估计成本为800 - 1000亿美元。目前尚无治愈或有效治疗方法，患者通常在发病后3-10年内死亡。迫切需要新的动物模型来快速测试抗-淀粉样蛋白疗法的疗效。我们已经发现了在试管中持续形成阿尔茨海默病淀粉样斑块样沉积物的新方法，并且正在建立一种新的淀粉样斑块在体内持续存在的动物模型。该模型可用于快速筛选新的抗淀粉样斑块治疗方法。

Alzheimer's disease (AD) is a degenerative brain disorder characterized clinically by progressive loss of memory, cognition, reasoning, judgement and emotional stability that gradually leads to profound mental deterioration and ultimately death. AD is characterized by the brain accumulation of insoluble fibrillar amyloid deposits containing the beta-amyloid protein (Abeta), either as extracellular amyloid plaques or in blood vessel walls in the brain parenchyma. Abeta amyloid persistence in brain is believed to play a central role in AD pathogenesis by contributing to neuronal loss and memory dysfunction. Over the last few years, our studies have determined that other additional factors, such as specific heparan sulfate proteoglycans (i.e. perlecan), are necessary for the formation and persistence of "fibrillar" Abeta deposits in AD brain. Use of purified perlecan has established a consistent rodent model for the rapid deposition, and persistence of Abeta amyloid in brain. 1 or 2- week infusions of Abeta + perlecan into hippocampus leads to congophilic amyloid deposits in 80 of 80 animals (100%), in comparison to 41 of 70 (58.5%) following infusions of Abeta alone. Perlecan contributes to the long- term persistence of Abeta amyloid in brain and the formation of cerebrovascular amyloid deposits, not observed following Abeta infusions. We have now significantly advanced this animal model by implementing new proprietary protocols to induce the in vitro formation of maltese-cross congophilic amyloid plaque-like deposits, which are morphologically and ultrastructurally similar to those amyloid plaque cores derived from AD brain. New animal modeling methodologies can be used for the rapid in vivo identification of potential anti-amyloid plaque therapeutics that target amyloid plaque a) deposition, b) persistence and/or c) dissolution and clearance, in brain. The major objectives of this phase I proposal are 1) to determine the role of proteoglycans/ GAGs on amyloid plaque formation, and 2) to determine anatomical and molecular consequences of "amyloid plaque", "fibrillar" Abeta persistence, and cerebrovascular amyloid deposition in brain. The studies described will further establish a consistent animal model for Abeta amyloid plaque deposition and persistence, and will allow (in a phase II proposal) for the rapid screening of new potential therapeutic candidates to treat Abeta plaque amyloidosis in AD. PROPOSED COMMERCIAL APPLICATIONS: Alzheimer's disease (AD) currently affects 4-5 million Americans, at an estimated costs of $80-$100 billion. Currently, there is no cure or effective treatment, and the patient usually dies within 3-10 years from disease onset. New animal models which can be implemented to rapidly test the efficacy of anti-Abeta amyloid therapeutics are desperately needed. We have discovered new methods to consistently form Alzheimer's amyloid plaque-like deposits in a test tube, and are establishing a new animal model of amyloid plaque persistence in vivo. This model can be utilized to rapidly screen for new anti- amyloid plaque therapeutics in the future.