Immunoprofiling postoperative delirium during aging and neurodegeneration

此R21应用程序使用高风险、高回报的质量细胞术(简称CyTOF)技术来 在井中确定介导中枢神经系统(CNS)神经炎症的免疫细胞亚群- 建立骨科小鼠术后勃起功能障碍模型。免疫失调是该病的一个特点 正常衰老；它也被认为是许多神经疾病的关键特征，包括痴呆和 围手术期的并发症，比如精神错乱。POD很常见，高达50%的老年患者骨折后会发生POD 修理。POD的最大危险因素是高龄和痴呆症。有趣的是，术后 精神错乱的出现可能是痴呆症的前兆。事实上，痴呆症叠加精神错乱(DSD)有助于 认知能力下降的速度更快，死亡率也更高。这一点意义重大，因为数百万人 每年定期接受整形外科或其他手术的老年患者。这些生物机制 衰老过程中的驱动POD和DSD是未知的，也没有批准的药物来治疗或预防它。我们有 开创了一种临床相关的骨科手术小鼠模型，显示出全身炎症，改变 小胶质细胞激活，并导致小鼠记忆障碍。在我们的模型中，手术动员离散的免疫细胞 具有促炎信号反应的人群，这些反应介导血脑屏障的损害 神经血管单位(NVU)和损害正常的突触转导。翻译过来，类似的免疫 具有相同促炎标志物的特征现在已经在神志不清的液体生物标志物中被描述 病人。然而，目前的免疫表型仅限于选定的非特异性细胞因子和亲本细胞因子。 肿瘤坏死因子、白介素1、白介素6、单核细胞趋化蛋白1和S100B等炎性分子在脑组织(啮齿动物)和脑脊液中的表达 液体(人类)。目前还没有研究试图无偏见地描述免疫子集对 中枢神经系统的骨科外科创伤。我们提出了两个具体目标：(1)定义年龄差异如何 幼年(6mos)和老年(22mos)雄性和雌性小鼠调节中枢神经系统和 骨科手术后的血液；以及(2)确定阿尔茨海默病(AD)样病理特征的影响 6个月龄(AD和术后神经炎时)的5xFAD转基因雄性和雌性小鼠 对整形外科手术后中枢神经系统和血液中的免疫细胞亚群有显著影响。这个 能够分解免疫细胞亚群，并将它们与促炎症信号的离散谱系相结合 细胞因子分子将是理解POD是否是由神经炎症引起的关键 外周迁移和/或驻留于中枢神经系统的免疫细胞。这些实验将为 在未来的RO1研究中，我们追求的关键发现集中在NVU的功能障碍与 NOT-AG-19-033寻求的阿尔茨海默病的神经退行性变。我们预计我们的发现将有一个 对ADRD领域的重要积极影响，以减少痴呆症和痴呆症对老龄人口的影响 通过帮助识别患POD和DSD风险更高的患者。

This R21 application uses the high risk, high reward technique of mass cytometry (abbreviated as CyTOF) to identify immune cell subsets that mediate neuroinflammation in the central nervous system (CNS) in a well- established orthopedic mouse model of postoperative delirium (POD). Dysregulated immunity is a hallmark of normal aging; it is also recognized as a key feature of many neurological disorders including dementia and perioperative complications like delirium. POD is common, occurring in up to 50% of older patients after a fracture repair. The strongest risk factors for POD are advanced age and dementia. Interestingly, the postoperative emergence of delirium may presage dementia. In fact, delirium superimposed on dementia (DSD) contributes to a faster trajectory of cognitive decline as well as significant mortality. This is significant because of the millions of elderly patients that routinely undergo orthopedic or other surgeries every year. The biologic mechanisms that drive POD and DSD during aging are unknown and without approved drugs to treat or prevent it. We have pioneered a clinically-relevant orthopedic surgery murine model that displays systemic inflammation, alters microglial activation, and causes memory deficits in mice. In our model, surgery mobilizes discrete immune cell populations with pro-inflammatory signaling responses that mediate damage to the blood-brain barrier, damage the neurovascular unit (NVU) and impair normal synaptic transduction. Translationally, similar immune signatures with the same pro-inflammatory markers have now been described in fluid biomarkers of delirious patients. However, current immunophenotyping is limited to selected non-specific cytokines and pro- inflammatory molecules such as TNF, IL-1, IL-6, MCP-1 and S100b in brain tissue (rodents) and cerebrospinal fluid (humans). No study has yet attempted to unbiasedly profile the immune subset specific response to orthopedic surgical trauma in the CNS. We propose two specific aims: (1) to define how age differences between young adult (6mos) and elderly (22mos) male and female mice modulate immune cell subsets in the CNS and blood after orthopedic surgery; and (2) to determine the impact of Alzheimer’s (AD)-like pathologic features using 5xFAD transgenic male and female mice at 6mos of age (when AD and postoperative neuroinflammation become pathologically significant) on immune cell subsets in the CNS and blood after orthopedic surgery. The ability to resolve immune cell subsets and align them with discrete repertoires of pro-inflammatory signaling molecules with CyTOF will be key to understanding whether POD results from neuroinflammation due to peripherally migrating and/or CNS-resident immunocytes. These experiments will provide the foundation for future RO1 studies in which we pursue key findings focused on dysfunction of the NVU associated with neurodegeneration in Alzheimer’s disease as sought by NOT-AG-19-033. We expect our findings to have an important positive impact on the ADRD field to reduce the impact of delirium and dementia in the aging population by helping identify patients at greater risk for developing POD and DSD.