Hybrid in vivo FMT-CT imaging of protease activity in atherosclerosis with customized nanosensors.
Hybrid in vivo FMT-CT imaging of protease activity in atherosclerosis with customized nanosensors.
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DOI：
10.1161/atvbaha.109.193086
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发表时间：
2009-10
期刊：
影响因子：
--
通讯作者：
Weissleder R
中科院分区：
文献类型：
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作者：
Nahrendorf M;Waterman P;Thurber G;Groves K;Rajopadhye M;Panizzi P;Marinelli B;Aikawa E;Pittet MJ;Swirski FK;Weissleder R
蛋白水解酶是炎症性疾病的新兴生物标志物。在动脉粥样硬化中，这些酶通常由炎性巨噬细胞分泌，消化纤维帽的细胞外基质，破坏动脉粥样硬化的稳定性。蛋白水解酶的功能可以用可激活的成像探针进行监测，并通过荧光分子断层扫描(FMT)进行体内定量。为了解决目前与小鼠动脉粥样硬化成像相关的两个主要限制因素(缺乏高度敏感的探针和缺乏解剖学信息)，我们比较了不同大小和药动学的蛋白酶传感器(PS)和共同注册的FMT数据集与计算机断层扫描(FMT-CT)。FMT和CT的联合配准是通过一个包含两种模式都能检测到的基准标记的多模式成像盒实现的。一种高分辨率CT血管成像方案准确地将荧光定位到动脉粥样硬化的载脂蛋白E−/−小鼠的主动脉根部。为了确定合适的传感器，我们首先在硅胶中建立了信号动力学模型，然后比较了三种具有相同寡聚-L-赖氨酸切割序列的探针：PS-5，直径5 nm，含有2个荧光染料的PS-25，25 nm版本的加长赖氨酸链的PS-25，以及PS-40，一种聚合物纳米颗粒。序列FMT-CT显示PS-5的动力学最快，但令人惊讶的是，在主动脉根部病变中PS-40的荧光最高。PS-40强有力地报道了阿托伐他汀的治疗效果，体外成像和模型组织蛋白B的定量聚合酶链式反应证实了阿托伐他汀的疗效。FMT-CT是一种强大的、独立于观察者的非侵入性评估炎症性小鼠动脉粥样硬化的工具。在活体成像方面，含报告纳米材料可能比小分子试剂具有独特的优势。
Proteases are emerging biomarkers of inflammatory diseases. In atherosclerosis, these enzymes are often secreted by inflammatory macrophages, digest the extracellular matrix of the fibrous cap and destabilize atheromata. Protease function can be monitored with protease activatable imaging probes and quantitated in vivo by fluorescence molecular tomography (FMT). To address two major constraints currently associated with imaging of murine atherosclerosis (lack of highly sensitive probes and absence of anatomical information), we compared protease sensors (PS) of variable size and pharmacokinetics and co-registered FMT datasets with computed tomography (FMT-CT). Co-registration of FMT and CT was achieved with a multimodal imaging cartridge containing fiducial markers detectable by both modalities. A high-resolution CT angiography protocol accurately localized fluorescence to the aortic root of atherosclerotic apoE−/− mice. To identify suitable sensors, we first modeled signal kinetics in-silico and then compared three probes with identical oligo-L-lysine cleavage sequences: PS-5, 5nm in diameter containing 2 fluorochromes , PS-25, a 25nm version with an elongated lysine chain and PS-40, a polymeric nanoparticle. Serial FMT-CT showed fastest kinetics for PS-5 but, surprisingly, highest fluorescence in lesions of the aortic root for PS-40. PS-40 robustly reported therapeutic effects of atorvastatin, corroborated by ex vivo imaging and qPCR for the model protease cathepsin B. FMT-CT is a robust and observer-independent tool for non-invasive assessment of inflammatory murine atherosclerosis. Reporter-containing nanomaterials may have unique advantages over small molecule agents for in vivo imaging.