Effects of Antiretrovirals on Neuronal Health: Screening ARVs for Neurotoxicity

描述(由申请人提供)： 尽管有足够的抗艾滋病毒药物治疗，但大约50%的艾滋病毒阳性退伍军人会患上艾滋病毒相关的神经认知障碍或手部疾病。与艾滋病毒感染相关的神经疾病范围从无症状的神经认知障碍(只能通过复杂的神经心理测试才能发现)到坦率的痴呆症。在美国等工业化国家，逆转录病毒药物疗法降低了因艾滋病毒感染而导致的严重痴呆症的发生率，但Hand的患病率出人意料地上升(尤其是在较轻的形式中)。原因尚不清楚(S)；然而，新的数据表明，用于对抗艾滋病毒感染的抗逆转录病毒药物(ARV)可能独立地发挥中枢神经系统(CNS)毒性，并导致不良神经症状的增加。较温和的手型更常见，发病时更隐蔽，会对退伍军人保持健康和经济安全的能力产生不利影响。令人惊讶的是，ARV对中枢神经系统神经元功能信号的直接影响还有待研究。通过这笔资金，我们有机会填补这一知识缺口。大多数积累的证据表明，抗艾滋病毒药物可能涉及认知功能障碍，这些证据是从涉及感觉神经元的VITR实验中推断出来的，或者是从设计上大多是观察性的临床研究中推断出来的。了解我们治疗艾滋病毒的潜在不利影响的机制是将其对健康的负面影响降至最低的唯一途径。这项拟议研究的主要目标是在没有炎症或感染的情况下检查ARV的中枢神经毒性。这将通过生理学、解剖学和行为学方法进行研究。通过在临床前研究中确定神经毒性的机制，我们可以开始为ARV治疗的这些并发症开发合理的治疗方法，并调整药物治疗方案，使其对现有认知功能障碍患者的中枢神经系统影响较小。由于手在时空记忆任务中可能首先表现为轻度认知障碍，我们的研究工作将集中在这些已知与记忆任务密切相关的大脑皮层区域。这项拟议工作的基本假设是，尽管它们在减少HIV负荷方面有效，但临床上与周围神经病变相关的某些ARV也会损害正常的皮质神经元解剖、生理和突触传递，这些神经生理学效应将导致记忆相关任务的可测量变化，无论是急性或通过慢性暴露。为了验证我的假设，我提议对不同的抗逆转录病毒药物(8种不同的药物)进行一系列体外和体外实验，以确定这些药物对皮质神经元的树突分支、兴奋性和网络活动的影响；从而建立潜在毒性抗逆转录病毒的生物物理图谱。然后，我将使用记忆障碍的体内行为测试来验证神经毒性的生物物理预测指标。然后使用最简单的生物物理测试方法建立一个有效的生物物理筛选，以检测ARV介导的神经毒性，该测试方法可以预测在整个动物中测量到的最严重的记忆损害。最后，我将只对所有常用的抗逆转录病毒药物应用必要的筛查工具，以简化神经毒性检测的方法。通过这个导师奖，我将把我的实验室技能扩展到我的神经生理学背景之外，包括行为和神经解剖技术。一旦掌握了必要的工具箱，我打算开发一个独立的科学计划，专注于将药理学测试转化为指导神经科学的临床决策。

DESCRIPTION (provided by applicant): Approximately 50% of HIV positive veterans develop HIV associated neurocognitive disorders, or HAND, despite adequate anti-HIV drug therapy. The neurologic disease associated with HIV infection ranges from asymptomatic neurocognitive impairment, only detected by sophisticated neuropsychological testing, to frank dementia. In industrialized nations like the United States, retroviral pharmacotherapy has reduced the incidence of severe dementia due to HIV infection, but the prevalence of HAND has unexpectedly risen (especially among the milder forms). The reason(s) for this is unclear; however, new data suggest that the antiretroviral agents (ARVs) used to combat HIV infection may independently exert central nervous system (CNS) toxicities and contribute to this increased prevalence of adverse neurologic symptomatology. The milder forms of HAND are more common, more insidious in their onset and can detrimentally impact a veteran's ability to remain healthy and financially secure. Surprisingly, the direct effects of ARV on functional signaling of CNS neurons has yet to be examined. Through this funding, we have the opportunity to fill that knowledge gap. The majority of the accumulated evidence that implicates anti-HIV drugs as potentially involved in cognitive dysfunction is inferred from in vitr experiments involving sensory neurons or derived from clinical studies that are mostly observational in their design. Understanding the mechanisms of the potential adverse effects of our treatments for HIV is the only way to minimize their negative impact on health. The primary goal of the proposed research is to examine ARVs for CNS neuronal toxicity in the absence of inflammation or infection. This will be investigated through physiological, anatomical, and behavioral approaches. By determining mechanisms of neurotoxicity in preclinical investigations, we can begin to develop rational treatments for these complications of ARV therapy and to adapt pharmacologic regimens to involve less toxic CNS effects in patients with existing cognitive dysfunction. As HAND may first manifest as mild cognitive impairment in spatiotemporal memory tasks, our research efforts will focus on these cortical brain regions known to be closely associated with memory tasks. The underlying hypotheses of the proposed work is that despite their efficacy in reducing HIV load, certain ARVs clinically associated with peripheral neuropathy will also impair normal cortical neuron anatomy, physiology, and synaptic transmission and these neurophysiological effects will lead to measurable changes on memory-associated tasks either acutely or via chronic exposure. To test my hypotheses, I am proposing to subject a diverse subset of the ARVs (8 separate drugs) to a battery of in vitro and ex vivo experiments in order to determine the effects of these drugs on the dendritic branching, excitability, and network activity of cortical neurons; thus establishing a biophysical profile of potentially toxic ARV. I will then validate biophysical predictors of neurotoxicity using in vivo behavioral testing of memory disruption. And then establish an efficient biophysical screen for ARV-mediated neurotoxicity using the simplest biophysical testing modality which predicts the most severe memory impairments measured in the whole animal. Finally, I will apply only the necessary screening tools to all of the commonly prescribed ARVs to streamline the method of neurotoxicity detection. Through this mentored award, I will extend my laboratory skills beyond my background in neurophysiology to include behavioral and neuroanatomical techniques. Once armed with the necessary toolbox, I intend to develop an independent science program focusing on translating pharmacological testing to guiding clinical decisions in the neurosciences.