Novel SIV Model of HAND

描述（由申请人提供）：HAART极大地改变了HIV的流行，延缓了疾病，延长了生命，并改变了HIV相关神经认知障碍（HAND）的性质，从显性痴呆转变为认知/运动障碍。抗逆转录病毒药物具有不同的渗透进入CNS的能力。尚不清楚人类HAART治疗中CNS渗透剂HAART是否通过减少CNS中的病毒复制和炎症来改善CNS结果，或者由于潜在神经毒性药物的较高CNS水平而矛盾地导致长期CNS损伤。我们开发并表征了一种严格的SIV猕猴模型的联合抗逆转录病毒治疗（cART），该模型与HIV感染个体的HAART非常相似，结合了具有低CNS转移率的抗逆转录病毒药物。该模型的价值在于：1）CD 4 + T细胞和单核细胞/巨噬细胞均被感染，2）HAART治疗的猕猴中包括脑和脾的组织携带病毒，准确模拟HIV感染者中的HAART，3）血液和淋巴组织中潜伏感染的静息CD 4+细胞的数量与HAART治疗的HIV感染患者相当。这些优势证明了该模型研究脑和外周神经系统中潜伏病毒储库的能力。病毒在大脑中的复制是检测在低水平使用敏感的 单拷贝测定; SIV DNA水平与未处理的SIV感染的猕猴相当，并且脑中存在持续的炎性变化。我们现在建议使用CNS渗透剂cART（pcART）研究SIV模型以确定其影响，并直接将其与非CNS渗透剂ART（ncART）进行比较，以1）控制病毒复制和炎症2）减少大脑中的病毒DNA库3）保留神经元功能的标记物。我们还将检查pcART与ncART在停止cART后延长病毒再活化时间的相对能力。我们的假设是，CNS渗透性cART在减少CSF和CNS中的残留病毒复制、减少脑中的病毒储库以及由于渗透增加而可能存在的其他组织中（如通过病毒DNA和残留病毒复制所测量的）、减少CNS炎症以及延迟cART停药后的病毒再活化方面将比非渗透性cART更有效。然而，CNS-渗透剂cART也可能具有神经毒性作用，在CNS和PNS两者中增加神经元损伤。我们将：1）在我们的SIV猕猴模型中使用优化的CNS-渗透cART（pcART）与非渗透cART（ncART）表征和比较血浆和CSF中SIV的衰变动力学;定量和比较pcART与ncART处理的动物中血浆、PBMC、CSF和组织中的残留病毒复制; 2）检测经pcART和ncART处理的SIV感染的猕猴的血液中的CD 4 + T细胞和单核细胞以及组织中的CD 4 +T细胞和巨噬细胞中的病毒潜伏期; 3）用pcART和ncART方案测量SIV感染的猕猴中神经元功能的CNS和PNS标志物，以评估神经保护和神经毒性; 4）比较pcART与ncART延迟或防止病毒从SIV感染的猕猴中的储库（包括CNS）再活化的能力。

DESCRIPTION (provided by applicant): HAART has dramatically changed the HIV epidemic, delaying disease, prolonging life and altering the nature of HIV-associated neurocognitive disorders (HAND) from overt dementia to cognitive/motor disorders. Antiretroviral drugs have differing capacities to penetrate into the CNS. It is not clear from HAART therapy in humans whether CNS-penetrant HAART improves CNS outcomes by reducing viral replication and inflammation in the CNS or paradoxically contributes to long term CNS damage due to higher CNS levels of potentially neurotoxic drugs. We developed and characterized a rigorous SIV macaque model of combined antiretroviral therapy (cART) that is very similar to HAART in HIV-infected individuals, combining classes of antiretroviral drugs that have low CNS penetrance. The value of this model is: 1) Both CD4+ T cells and monocyte/macrophages are infected, 2) tissues including brain and spleen harbor virus in HAART-treated macaques, accurately modeling HAART in HIV-infected humans, 3) the number of latently infected resting CD4+ cells in blood and lymphoid tissues is comparable to that in HIV-infected patients on HAART. These advantages demonstrate the model's ability to study latent viral reservoirs in brain and the peripheral nervous system. Virus replication in brain is detectable at low levels using a sensitive single copy assay; SIV DNA levels were comparable to untreated SIV-infected macaques, and there were ongoing inflammatory changes in brain. We now propose to study a SIV model using CNS-penetrant cART (pcART) to determine its impact and compare it directly with non-CNS-penetrant ART (ncART) for ability to 1) control viral replication& inflammation 2) reduce viral DNA reservoirs in brain 3) preserve markers of neuronal function. We will also examine the relative ability of pcART versus ncART to prolong time to virus reactivation after stopping cART. Our hypothesis is that CNS-penetrant cART will be more effective than non-penetrant cART in reducing residual viral replication in CSF and CNS, in reducing viral reservoirs in brain, and potentially other tissues due to increased penetration, as measured by viral DNA and residual virus replication, in reducing CNS inflammation, and in delaying virus reactivation upon withdrawal of cART. However, CNS-penetrant cART might also have neurotoxic effects with increased neuronal damage in both CNS and PNS. We will: 1) Characterize and compare decay kinetics of SIV in plasma and CSF using an optimized CNS-penetrant cART (pcART) to non- penetrant cART (ncART) in our SIV macaque model; quantitate and compare residual virus replication in plasma, PBMCs, CSF and tissues in pcART versus ncART-treated animals; 2) Examine viral latency in CD4+T cells and monocytes in blood and CD4+T cells and macrophages in tissues of SIV-infected macaques treated with pcART & ncART; 3) Measure CNS and PNS markers of neuronal function in SIV-infected macaques with pcART & ncART regimens to evaluate neuroprotection and neurotoxicity; 4) Compare ability of pcART versus ncART to delay or prevent reactivation of virus from reservoirs including the CNS in SIV-infected macaques.