Lee Moonhee, Guo Jian-Ping, Kennedy Krista, McGeer Edith G, McGeer Patrick L
J Alzheimers Dis. 2017;55(3):1175-1182. doi: 10.3233/JAD-160748.
We have developed a non-invasive method of diagnosing Alzheimer's disease (AD), which can also predict the risk of its future onset. It is based on measuring salivary levels of amyloid-β protein terminating at position 42 (Aβ42). Brain deposits of this peptide are characteristic of AD. Biomarker studies indicate that such brain deposits commence a decade or more prior to clinical onset of the disease. We report here that Aβ42 is produced in all peripheral organs tested, thus establishing the generality of its production. We used this information to develop simple and sensitive tests to determine salivary Aβ42 levels. The levels were first stabilized by adding thioflavin S as an anti-aggregation agent and sodium azide as an anti-bacterial agent. We then quantitated the Aβ42 in a series of samples with ELISA type tests. Control cases showed almost identical levels of salivary Aβ42 regardless of sex or age. All AD cases secreted levels of Aβ42 more than double those of controls. Individuals at elevated risk of developing AD secreted levels comparable to the AD cases. The results establish that salivary Aβ42 levels can be used to diagnose AD as well as to predict the risk of its future onset.
我们开发了一种诊断阿尔茨海默病（AD）的非侵入性方法，该方法还能预测其未来发病风险。它基于测量唾液中42位终止的β-淀粉样蛋白（Aβ42）水平。这种肽的脑内沉积物是AD的特征。生物标志物研究表明，这种脑内沉积物在疾病临床发作前十年或更早便已开始形成。我们在此报告，Aβ42在所有测试的外周器官中均有产生，从而确定了其产生的普遍性。我们利用这一信息开发了简单且灵敏的检测方法来测定唾液Aβ42水平。首先通过添加硫黄素S作为抗聚集剂和叠氮化钠作为抗菌剂来稳定水平。然后我们用ELISA类型的检测方法对一系列样本中的Aβ42进行定量。对照病例显示，无论性别或年龄，唾液Aβ42水平几乎相同。所有AD病例分泌的Aβ42水平是对照病例的两倍多。有患AD高风险的个体分泌的水平与AD病例相当。结果表明，唾液Aβ42水平可用于诊断AD以及预测其未来发病风险。
