Novel SIV Model of HAND

描述(申请人提供)：HAART极大地改变了艾滋病毒的流行，延缓了疾病，延长了生命，并改变了艾滋病毒相关神经认知障碍(HAND)的性质，从明显的痴呆症转变为认知/运动障碍。抗逆转录病毒药物具有不同的穿透中枢神经系统的能力。人类的HAART治疗尚不清楚CNS穿透性HAART是通过减少CNS中的病毒复制和炎症来改善CNS预后，还是矛盾地由于CNS潜在神经毒性药物水平的增加而导致长期CNS损害。我们开发并鉴定了一种严格的SIV猕猴联合抗逆转录病毒疗法(CART)模型，该模型非常类似于HIV感染者的HAART，将具有低中枢神经系统渗透率的抗逆转录病毒药物类别结合在一起。该模型的价值是：1)CD4+T细胞和单核/巨噬细胞都被感染；2)HAART治疗的猕猴体内包括脑和脾在内的组织中含有病毒，准确地模拟了HIV感染者的HAART；3)血液和淋巴组织中潜伏感染的静止CD4+细胞的数量与HAART上HIV感染患者的数量相当。这些优势表明，该模型有能力研究大脑和周围神经系统中的潜伏病毒库。病毒在大脑中的复制是可以在低水平检测到的 单拷贝分析：SIV DNA水平与未经处理的感染SIV的猕猴相当，大脑中存在持续的炎性变化。我们现在建议研究一种使用CNS穿透性CART(PcART)的SIV模型，以确定其影响并直接与非CNS穿透性ART(NcART)进行比较：1)控制病毒复制和炎症；2)减少大脑中的病毒DNA储存库；3)保存神经元功能的标志。我们还将检查pcART和ncART在停止CART后延长病毒重新激活时间的相对能力。我们的假设是，CNS穿透性CART在减少脑脊液和CNS中的残留病毒复制方面将比非穿透性CART更有效，在减少脑内和潜在的其他组织中的病毒库方面，根据病毒DNA和残留病毒复制的测量，在减少CNS炎症方面，在延迟病毒在CART停用时的重新激活方面，更有效。然而，CNS穿透性CART也可能具有神经毒性作用，导致CNS和PNS神经元损伤增加。我们将：1)在我们的SIV猕猴模型中，使用优化的CNS穿透性CART(PcART)和非穿透性CART(NcART)来表征和比较SIV在血浆和脑脊液中的衰变动力学；量化和比较在pcART和ncART治疗的动物中SIV在血浆、PBMC、脑脊液和组织中的残留病毒复制；2)检测SIV感染猕猴血液中CD4+T细胞和单核细胞中的病毒潜伏时间以及SIV感染猕猴组织中CD4+T细胞和巨噬细胞的病毒潜伏期；3)用PCART和ncART方案测量SIV感染猕猴神经功能的CNS和PNS标记物，以评估神经保护和神经毒性；4)比较pcART和ncART在延缓或防止SIV感染猕猴体内包括中枢神经系统在内的蓄水池病毒重新激活的能力。

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.