Neuroinflammation is thought to be important in the progression of Alzheimer's disease (AD). To evaluate cerebral inflammation using positron emission tomography (PET) imaging with a radioligand that target TSPO, a translocator protein upregulated in microglia and macrophages during inflammation, can be used in conjunction with positron emission tomography (PET) imaging. In AD patients, neuroinflammation is up-regulated compared to both healthy volunteers as well as to subjects with mild cognitive impairment (MCI). Peripheral biomarkers, such as serum cytokines and total fatty acids (FAs), can also be indicative of the inflammatory state of subjects with neurodegenerative disorders. To understand whether peripheral biomarkers are predictive of neuroinflammation we conducted a secondary exploratory analysis of two TSPO imaging studies conducted in subjects with AD, MCI and aged matched healthy volunteers. We examined the association between candidate peripheral biomarkers (including amyloid beta, cytokines and serum total fatty acids) with brain TSPO levels. Our results showed that serum IL-6 and IL-10 are higher in AD compared to the MCI and healthy volunteers while levels of some fatty acids are modulated during the disease. A limited number of associations were observed between region-specific inflammation and fatty acids in MCI patients, and between amyloid beta 42 and brain inflammation in AD, however no associations were present with systemic cytokines. Our study suggests that while TSPO binding and systemic IL-6 and IL-10 were elevated in AD, serum amyloid beta, cytokines and fatty acids were generally not predictive of the disease nor correlated with neuroinflammation.

中文翻译：

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外周细胞因子和脂肪酸与 AD 和 aMCI 患者神经炎症的关联：一项探索性研究

神经炎症被认为在阿尔茨海默病 (AD) 的进展中很重要。使用正电子发射断层扫描 (PET) 成像与靶向 TSPO 的放射性配体评估脑炎症，炎症期间小胶质细胞和巨噬细胞中的易位蛋白上调，可与正电子发射断层扫描 (PET) 成像结合使用。在 AD 患者中，与健康志愿者以及轻度认知障碍 (MCI) 受试者相比，神经炎症均上调。外周生物标志物，例如血清细胞因子和总脂肪酸 (FA)，也可以指示患有神经退行性疾病的受试者的炎症状态。为了了解外周生物标志物是否可以预测神经炎症，我们对在 AD、MCI 和老年匹配健康志愿者中进行的两项 TSPO 成像研究进行了二次探索性分析。我们检查了候选外周生物标志物（包括淀粉样蛋白 β、细胞因子和血清总脂肪酸）与大脑 TSPO 水平之间的关联。我们的结果表明，与 MCI 和健康志愿者相比，AD 中的血清 IL-6 和 IL-10 更高，而某些脂肪酸的水平在疾病期间受到调节。在 MCI 患者中观察到区域特异性炎症与脂肪酸之间以及淀粉样蛋白 42 与 AD 中的脑炎症之间存在有限数量的关联，但与全身细胞因子不存在关联。