Blinded Comparison of Different Alpha-Synuclein Seeding Assays as Cutaneous Biomarkers of Lewy Body Dementias

摘要 随着人口寿命的延长，痴呆症被广泛认为是一种迫在眉睫的公共健康危机。 路易体痴呆(LBD)，包括路易体痴呆(DLB)和帕金森病痴呆 (PDD)是第二个最常见的原因。LBD的特点是异常聚集和堆积 一种蛋白质，α-突触核蛋白(ASyn)。临床上，PDD和DLB仅通过发病的相对时间来区分 帕金森症和痴呆症。目前，这些疾病的治疗进展受到严重阻碍。 由于缺乏能够提供准确诊断和预后的非侵入性、廉价的生物标志物 信息。这种情况可能很快就会得到解决，因为近年来，通过我们自己的 研究和其他研究表明，外周组织部位的活组织检查可以发现具有诊断意义的aSyn。 我们的项目将评估a Syn在皮肤穿孔活检中的作用。我们来自新的“播种试验”的初步数据 方法包括实时抖动诱导转换(RT-QuIC)和蛋白质错误折叠循环扩增 来自尸检确认的LBD患者的(PMCA)显示出高敏感性和特异性，用于预测 在受影响的受试者的皮肤中存在Syn。要在生活中证实这些结果，还需要进一步的工作 符合这些条件的受试者，这是本拟议项目的目标。我们会做两次活组织检查 在四年的时间里，90名aSyn病患者，30名PD，PDD和DLB患者，以及30名正常对照 研究对象。两个独立的实验室将盲目地进行单独开发的种子分析，严格 测试实验室间的可靠性，并提供aSyn密度随时间变化的估计。播种 化验结果将与目前的金标准活检法进行比较， 免疫组织化学(IHC)。所有受试者将在两点接受认知和运动障碍评估。 在这个为期四年的项目中的时间点，可以将测试指标与认知和运动能力下降进行比较 费率。许多受试者将参加亚利桑那州关于衰老和神经退行性疾病的研究 (AZSAND)，尸检率超过90%的纵向临床病理研究。这将允许在一个 帕金森综合征的分子病因的实质性亚集，最终神经病理学确认 每个受试者都患有痴呆症。

Abstract With increasing longevity in our population, dementia is widely recognized as an impending public health crisis. Lewy body dementia (LBD), encompassing dementia with Lewy bodies (DLB) and Parkinson disease dementia (PDD), is the second most common cause. LBD is characterized by abnormal aggregation and accumulation of a protein, α-synuclein (aSyn). PDD and DLB are clinically separated only by the relative timing of the onset of parkinsonism and dementia. At present, advances in the treatment of these conditions are critically hampered by the lack of non-invasive, inexpensive biomarkers that can provide accurate diagnostic and prognostic information. This situation may soon be resolved, as in recent years it has become apparent, through our own studies and those of others, that biopsies of peripheral tissue sites can detect diagnostically significant aSyn. Our project will assess aSyn in punch biopsies of the skin. Our preliminary data from new “seeding assay” methods including real-time quaking-induced conversion (RT-QuIC) and protein misfolding cyclic amplification (PMCA), from autopsy-confirmed LBD subjects, indicate high sensitivity and specificity for predicting the presence of aSyn in the skin of affected subjects. Further work is necessary to confirm these results in living subjects with these conditions, which is the objective of this proposed project. We will biopsy, twice during a four year period, 90 subjects with aSyn disease, 30 each with PD, PDD and DLB, as well as 30 normal control subjects. Two independent laboratories will blindly perform separately-developed seeding assays, rigorously testing the interlaboratory reliability and providing estimates of aSyn density change over time. The seeding assay results will be compared with those obtained by the current gold-standard biopsy method, immunohistochemistry (IHC). All subjects will receive cognitive and movement disorder assessments at two timepoints in this four year project, enabling comparisons of assay measures with cognitive and motor decline rates. Many of the subjects will be enrolled in the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND), a longitudinal clinicopathological study with an autopsy rate exceeding 90%. This will allow, in a substantial subset, eventual neuropathological confirmation of the molecular cause of parkinsonism and dementia in each subject.