Quantitative Correlation of the MR-Angiography and Atherosclerosis Probe VSOP in Atherosclerotic Plaques with Markers for PlaqueInstability by Element Microscopy (LA-ICP-MS)

我们已经证明，超顺磁性非常小的氧化铁颗粒(VSOP)不仅非常适合于磁共振血管成像(MRA)，而且还可以非常灵敏地检测动脉粥样硬化斑块，与其他几种阴离子纳米颗粒相比，它们被发现是最适合的。与立体稳定的氧化铁纳米粒子(例如，已被批准用于铁替代治疗的阿魏酸甘油)不同，VSOP由于其快速的动力学特性，有可能在单个MR成像会话中在不到3小时内进行联合MRA和斑块成像。最近，我们已经表明，与现有的方法(例如，普鲁士蓝铁染色，与内源性组织铁的非特异性)相比，首次将铕标记的VSOP(EU-VSOP)与激光消融电感耦合等离子体质谱(LA-ICP-MS)相结合，可以选择性、灵敏和定量地识别组织切片中的氧化铁纳米粒子。在拟议的项目中，我们打算使用这一组合来调查哪些典型的炎症和易损性标记物与动脉粥样硬化斑块中VSOP的积聚相关，以及含有内源性或颗粒铁的区域是否包含活性氧物种(ROS)。当用不同的稀土元素标记抗体时，这项技术允许在同一组织切片中同时将几个标记与EU-VSOP相关联(多路传输)。为了进行比较，计划进行常规的免疫组织学染色，然后(在移除盖片后)用LA-ICPMS额外研究这些制剂。最后，Eu-VSOP将通过在Eu通道中应用电感耦合等离子体质谱来进行器官分布的非放射性测定。这些研究对于了解VSOP在斑块中的积聚和VSOP的临床翻译具有很高的相关性。

We have shown that superparamagnetic very small iron oxide particles (VSOP) are not only well suited for magnetic resonance angiography (MRA) but also allow very sensitive detection of atherosclerotic plaques, for which they have been found to be most suitable compared with several other anionic nanoparticles. Unlike sterically stabilized iron oxide nanoparticles (e.g., ferumoxytol, approved for iron replacement therapy) VSOP have due to their fast kinetics the potential for performing combined MRA and plaque imaging in less than 3 hours in a single MR imaging session.Recently, we have shown that, in contrast to established methods, (e.g., Prussian blue iron staining, unspecific with endogenous tissue iron) the combination of Europium-doted VSOP (Eu-VSOP) with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for the first time allows selective, sensitive, and quantitative identification of iron oxide nanoparticles in tissue sections. In the proposed project, we intend to use this combination to investigate which typical markers of inflammation and vulnerability correlate with VSOP accumulation in atherosclerotic plaques and whether areas with endogenous or particle iron contain reactive oxygen species (ROS). When antibodies are labeled with different lanthanoids, this technique allows simultaneous correlation of several markers with Eu-VSOP in the same tissue section (multiplexing). For comparison, it is planned to perform conventional immunohistological staining and to then (after removal of the cover slips) additionally investigate these preparations with LA-ICP-MS. Finally, the Eu-VSOP will be used for nonradioactive determination of organ distribution by applying ICP-MS in the Europium channel. These investigations are highly relevant for understanding VSOP accumulation in plaques and for clinical translation of VSOP.