Alzheimer's disease (AD) is the most common cause of dementia. Senile plaques, consisting of β-amyloid, and neurofibrillary tangles (NFTs), composed of tau protein, are representative pathological hallmarks of AD. It is believed that the accumulation of NFTs precedes the onset of clinical symptoms of AD and correlates with the progression of memory dysfunction. Thus, the use of noninvasive detection techniques including radiolabeled probes and positron emission tomography (PET) will facilitate early diagnosis or staging of AD. In this study, we synthesized and evaluated novel hydroxylated 2-arylquinoline derivatives as tau imaging PET probes. The binding affinities of compounds for tau were evaluated by fluorescent staining of the AD hippocampal section and a competitive binding assay using [18F]THK-523. THK-951 showed high binding affinity for tau pathology in an AD brain section and K18Δ280K fibrils (Ki = 20.7 nM); thus, we radiosynthesized a 11C-labeled THK-951 and further studied its potential as a tau PET probe. The [11C]THK-951 demonstrated excellent kinetics in a normal mouse brain (3.23% ID/g at 2 min postinjection and 0.15% ID/g at 30 min postinjection) and showed the labeling of NFTs in an AD brain section by autoradiography assay. These findings indicate the availability of [11C]THK-951 for in vivo PET imaging of tau pathology in AD. Copyright © 2013 John Wiley & Sons, Ltd.
阿尔茨海默病(AD)是导致痴呆症的最常见原因。老年斑(由β-淀粉样蛋白组成)和神经纤维缠结(NFTs,主要由tau蛋白组成)是AD的典型病理特征。研究认为,NFT的积累在临床症状出现之前,并与记忆功能障碍的进展相关。因此,采用包括放射性标记探针和正电子发射断层扫描(PET)在内的非侵入性检测技术将有助于AD的早期诊断或分期。在本研究中,我们合成并评估了新型羟基化2-芳基
喹啉衍
生物作为tau成像的PET探针。通过对AD海马切片的荧光染色和使用[18F]THK-523的竞争结合实验,评估了化合物与tau的结合亲和力。THK-951在AD脑切片和K18Δ280K纤维中显示出对tau病理的高结合亲和力(Ki = 20.7 nM);因此,我们放射合成了11C标记的THK-951,并进一步研究其作为tau PET探针的潜力。[11C]THK-951在正常小鼠脑中表现出优良的动力学(注射后2分钟为3.23% ID/g,注射后30分钟为0.15% ID/g),并通过自显影实验显示在AD脑切片中标记了NFT。这些发现表明[11C]THK-951可用于AD中tau病理的体内PET成像。版权 © 2013 John Wiley & Sons, Ltd.