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描述（由申请人提供）： 我们实验室最近的研究表明，心脏中的血管生成脉管系统可以使用由天冬酰胺-甘氨酸-精氨酸（NGR）组成的合成肽序列进行靶向和成像。该归巢序列的血管地址是细胞表面氨肽酶，氨肽酶N（APN），也称为CD 13。在心脏血管生成中，我们已经确定，CD 13/APN在新生血管系统中的内皮细胞上强烈上调，并且在血管生成区域外的静止血管上不能检测到。此外，我们已经表明，使用NGR与不同的荧光分子和生物素的缀合物，心脏新生血管可以被靶向和成像选择性地与这些缀合物。在其他研究中，我们已经表明，在内皮细胞上，CD 13/APN响应于缺氧、血管生成生长因子（HIF-1 α、bFGF和VEGF）而上调。基于这些研究，我们建议利用这种新的血管地址和多功能NGR归巢序列来研究在心肌梗死（MI）和后肢缺血（HLI）背景下通过靶向成像识别的血管生成血管系统所起的作用。在小鼠MI和HLI模型中，我们将NGR荧光强度和断层扫描与通过微CT、双光子显微镜和连续组织切片的新生血管的3D图像以及组织灌注、氧合和左心室（L. V.）功能结合NGR的新生血管的分子表征将通过使用激光解剖显微镜进行，以分离结合荧光标记的NGR的内皮细胞和不结合NGR的内皮细胞，然后进行微阵列表达分析。将在猪心肌缺血模型中使用NGR-铁颗粒测试NGR成像的临床适用性，并将在小鼠中并通过活内皮细胞的共聚焦和电子显微镜研究生物分布、药代动力学和内化。 (End摘要）

DESCRIPTION (provided by applicant): Recent studies from our laboratory have demonstrated that angiogenic vasculature in the heart can be targeted and imaged using a synthetic peptide sequence consisting of asparagine-glycine-arginine (NGR). The vascular address for this homing sequence is a cell surface aminopeptidase, aminopeptidase N (APN) also known as CD13. In cardiac angiogenesis we have established, that CD13/APN is strongly up-regulated on endothelial cells in the neo-vasculature, and that it cannot be detected on quiescent vessels outside the angiogenic area. Furthermore, we have shown, using conjugates of NGR with different fluorescent molecules and with biotin, that cardiac neo-vessels can be targeted and imaged selectively with these conjugates. In other studies, we have shown that on endothelial cells CD13/APN is up-regulated in response to hypoxia, angiogenic growth factors (HIF-la, bFGF and VEGF). Based on these studies we propose to utilize this novel vascular address and the versatile NGR homing sequence to study the role played by the angiogenic vasculature that is identified by targeted imaging in the setting of myocardial infarction (MI), and in hind limb ischemia (HLI). In mouse MI and HLI models we will co-register NGR fluorescence intensity and tomography with 3D images of neo-vessels by micro-CT, 2 photon microscopy and serial histological sections together with indices of tissue perfusion, oxygenation and left ventricular (L.V.) function. Molecular characterization of neo-vessels that bind NGR, will be performed by using laser dissection microscopy to isolate endothelial cells that bind fluorescently labeled NGR and endothelial cells that do not bind NGR that will then be subjected to microarray expression analysis. Clinical applicability of NGR imaging will be tested with NGR-iron particles in a porcine model of myocardial ischemia and bio-distribution, pharmacokinetics and internalization will be studied in mice and by confocal and electron microscopy of live endothelial cells. (End of Abstract)