Novel Therapies to Improve Functional Recovery After Stroke

描述(由申请人提供)： 中风是美国第三大致死原因，也是导致长期残疾的主要原因。中风的风险随着年龄的增长而显著增加，随着越战时代的退伍军人继续老龄化，退伍军人的平均年龄将继续增加。该项目的总体目标是开发和表征新的治疗策略，这些策略将改善结果并减少中风后的长期残疾。脑缺血和随后的再灌流可引发一系列事件，导致炎症和继发性神经元损伤，导致梗塞范围增加和较差的临床预后。补体系统在缺血性卒中的病理生理学中起着核心作用。我们建议研究补体在卒中后脑损伤中的致病机制和保护机制，并开发和表征新的补体抑制策略，以减少继发性组织损伤，改善认知和长期功能恢复。拟议的研究集中在临床前卒中小鼠模型中靶向补体抑制剂的特征。我们已经证明了靶向和全身性补体抑制在包括缺血性中风在内的中枢神经系统损伤模型中的显著益处，在这里，我们建议表征第二代靶向补体抑制剂，它针对缺血后受损的脑组织。我们的靶向策略包括将不同类型的补体抑制剂连接到单链抗体(ScFv)的靶向部分。我们将在两种不同的卒中模型中描述不同的靶向性和不同类型的补体抑制剂，并从组织损伤、组织修复和再生以及认知和功能恢复的角度确定短期和长期治疗结果。在目标1中，我们将在小鼠大脑中动脉闭塞(MCAO)模型中鉴定重组蛋白。这是一个很有特点的模型，可以与以前的数据和存档的数据进行比较。我们将研究再灌注后的治疗窗口，以及不同新表位在缺血脑组织中的时间表达(这可能表明不同的靶向策略，取决于卒中后何时给予抑制剂)。我们还将探索对脑血管内皮细胞更具选择性的应激/损伤新表位。 以确定提供治疗药物的其他目标。在目的2中，我们将使用相同的MCAO模型来研究不同重组蛋白在组织损伤和修复、认知功能和功能恢复方面对远期结局的影响。这些研究还将探讨补体在损伤和修复/神经再生中的双重作用。在目标3中，我们将在微栓子性卒中模型中描述最有希望的候选抑制剂。微栓子模型可以更好地控制血栓负荷、血流灌注障碍和神经功能障碍。这里的重点将是认知和功能评估以及长期康复。该模型还可以结合补体抑制疗法评估血栓的自发溶解和治疗性溶解。这将提供重要的临床前数据，因为目前唯一被批准的治疗缺血性中风的药物是组织型纤溶酶原激活剂(TPA)。

DESCRIPTION (provided by applicant): Stroke is the third leading cause of death in the United States and the main cause of long-term disability. The risk of stroke increases significantly with age, and the average age of Veterans will continue to increase as Veterans from the Vietnam era continue to age. The overall goals of this project are to develop and characterize novel therapeutic strategies that will improve outcome and reduce long-term disability after stroke. Cerebral ischemia and subsequent reperfusion initiates a cascade of events that can lead to inflammation and secondary neuronal damage resulting in an increased extent of infarct and poorer clinical outcome. The complement system plays a central role in the pathophysiology of ischemic stroke. We propose to investigate the pathogenic, as well as the protective mechanisms of complement that are involved in cerebral injury after stroke, and to develop and characterize novel complement inhibitory strategies for reducing secondary tissue injury and improving cognitive and long-term functional recovery. The proposed studies are focused on the characterization of targeted complement inhibitors in pre-clinical murine models of stroke. We have demonstrated the significant benefits of targeted versus systemic complement inhibition in models of CNS injury, including ischemic stroke, and here we propose to characterize second-generation targeted complement inhibitors that target to injured brain tissue after ischemia. Our targeting strategy consists of linking different types of complement inhibitor to single chain antibody (scFv) targeting moieties. We will characterize different targeting specificities and different types of complement inhibitor in two different models of stroke, and determine short-term and long-term therapeutic outcome in terms of tissue injury, tissue repair and regeneration, and cognitive and functional recovery. In aim 1, we will characterize the recombinant proteins in a mouse model of middle cerebral artery occlusion (MCAO). This is a well characterized model and will allow comparisons with previous and archived data. We will investigate the post-reperfusion treatment window, and the temporal expression of different neoepitopes on the ischemic brain (which may indicate different targeting strategies, depending on when inhibitor is administered after stroke). We will additionally explore stress/injury neoepitopes that are more selective for brain endothelial cells in an attempt to identify additional targets for delivery of therapeutics. In aim 2, we will use the same MCAO model to investigate the effect of the different recombinant proteins in long-term outcome, in terms of tissue injury and repair, cognitive function and functional recovery. These studies will also address the dual role of complement in injury and repair/neuroregeneration. In aim 3, we will characterize the most promising candidate inhibitors in a model of microembolic stroke. The microembolic model allows more control over clot burden, perfusion impairment and neurological deficit. A focus here will be cognitive and functional evaluation and long-term recovery. The model also allows evaluation of spontaneous and therapeutic dissolution of clots in combination with complement inhibitory therapy. This will provide important pre-clinical data since the only currently approved treatment for ischemic stroke is tissue plasminogen activator (tPA).