Imaging of amyloid-β deposits in brains of living mice permits direct observation of clearance of plaques with immunotherapy
Imaging of amyloid-β deposits in brains of living mice permits direct observation of clearance of plaques with immunotherapy
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DOI：
10.1038/85525
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发表时间：
2001-03-01
期刊：
影响因子：
82.9
通讯作者：
Hyman, BT
中科院分区：
文献类型：
--
作者：
Backskai, BJ;Kajdasz, ST;Hyman, BT
新发现65个斑块中的45个（70%）在初次成像后3天清除。16 B5组45个斑块中，3天后仅有9个斑块清除（20%，χ2= 30.5，P< 0.001）。该结果表明，致密核心淀粉样蛋白-β沉积物被10 D5应用逆转。接下来，我们通过在初始成像阶段使用标记的10 D5作为成像剂重复实验来检查是否所有免疫可检测形式的淀粉样蛋白-β沉积物都可以通过免疫疗法清除。正如预期的那样，标记的10 D5显示了无数的弥漫性和致密核心淀粉样蛋白-β沉积物。动物恢复，无事件发生，三天后重新成像。在三天前施用的荧光素标记的10 D5的应用中保留非常少或不可检测的荧光;然后将标记的10 D5直接重新应用于两个治疗组的皮质。用标记的3D 6（一种识别斑块上不同表位的单克隆抗体）重复成像（如在低温恒温器切片上评估的），显示在初始成像时存在的淀粉样蛋白-β沉积物很少或没有残留。仍检测到淀粉样血管病（图3）。因此，在单次应用抗淀粉样蛋白-β抗体后三天，我们观察到实质中淀粉样蛋白-β沉积物显著消退。可能的是，血管淀粉样蛋白沉积物更不易接近、更稳定或更快速地补充，因为尽管用抗淀粉样蛋白-β抗体标记，它们似乎基本上没有变化。然而，不能排除三天内血管周围淀粉样蛋白的微小变化。在6只动物中的每只动物的一个或两个部位进行初始成像后延迟3至8天的重复实验显示出几乎相同的结果。在5只动物中进行假实验，其中在初始成像阶段中使用荧光素标记的抗体16 B5。使用抗体16 B5的初始成像阶段根本没有成像任何淀粉样蛋白-β。这是预期的，因为单克隆抗体不针对老年斑上存在的表位。3至5天后，使用标记的10 D5重复成像，成像了许多淀粉样蛋白-β沉积物，其与最初用10 D5成像的6只小鼠中的任何一只的初始成像期不可区分。因此，手术准备、应用不相关的单克隆抗体或成像本身似乎不会导致淀粉样蛋白-β沉积物的消退。由于体内免疫荧光技术成像扩散，
NEW TECHNOLOGY45 of 65 plaques (70%) were cleared 3 days after initial imaging. In the 16B5 group, only 9 of 45 plaques were cleared after 3 days (20%; χ2= 30.5, P< 0.001). This result demonstrates that dense-core amyloid-β deposits are reversed by 10D5 application. We next examined whether all immunodetectable forms of amyloid-β deposits could be cleared by immunotherapy by repeating the experiment using labeled 10D5 as the imaging agent at the initial imaging session. As expected, the labeled 10D5 revealed innumerable diffuse and dense-core amyloid-β deposits. The animals recovered without incident and three days later were re-imaged. Very little or no detectable fluorescence remained from the application of fluorescein-labeled 10D5 that had been administered three days before; labeled 10D5 was then re-applied directly to the cortex in both treatment groups. Repeat imaging with labeled 3D6, a monoclonal antibody that recognizes a distinct epitope on plaques (as assessed on cryostat sections), showed that few or none of the amyloid-β deposits that were present at the initial imaging remained. Amyloid angiopathy was still detected (Fig. 3). Thus, three days after a single application of anti-amyloid-β antibody, we observed dramatic resolution of amyloid-β deposits in the parenchyma. It is possible that the vascular amyloid deposits are less accessible, more stable or more rapidly replenished, as they appear largely unchanged, despite the labeling with anti-amyloid-β antibody. However, small changes in the amyloid surrounding blood vessels over three days cannot be ruled out. Replication of this experiment with 3-to 8-day delays after initial imaging in one or two sites in each of 6 animals showed nearly identical results. Sham experiments were carried out in five animals in which fluorescein-labeled antibody 16B5 was used in the initial imaging session. The initial imaging session, using antibody 16B5, did not image any amyloid-β at all. This was expected as the monoclonal antibody was not directed against an epitope present on senile plaques. Repeat imaging 3 to 5 days later using labeled 10D5 imaged numerous amyloid-β deposits that were indistinguishable from the initial imaging sessions of any of the 6 mice initially imaged with 10D5. Thus it does not appear that the surgical preparation, application of an irrelevant monoclonal antibody, or imaging per se led to resolution of amyloid-β deposits. As the in vivo immunofluorescence technique images both diffuse