Amirbekian Vardan, Aguinaldo Juan Gilberto S, Amirbekian Smbat, Hyafil Fabien, Vucic Esad, Sirol Marc, Weinreb David B, Le Greneur Soizic, Lancelot Eric, Corot Claire, Fisher Edward A, Galis Zorina S, Fayad Zahi A
Translational and Molecular Imaging Institute, Department of Radiology, Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai Schoolof Medicine, New York, NY 10029, USA.
Radiology. 2009 May;251(2):429-38. doi: 10.1148/radiol.2511080539.
To evaluate the capability of P947, a magnetic resonance (MR) imaging contrast agent that molecularly targets matrix metalloproteinases (MMPs), to aid detection and imaging of MMPs in atherosclerotic lesions in vivo; its specificity compared with that of P1135; expression and distribution of MMPs in atherosclerotic vessels; and in vivo distribution and molecular localization of fluorescent europium (Eu) P947.
The Animal Care and Use Committee approved all experiments. P947 was synthesized by attaching a gadolinium chelate (1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid) to a peptide that specifically binds MMPs. Scrambled form of P947 (P1135) was synthesized by replacing the targeting moiety of P947 with a scrambled peptide lacking the ability to bind MMPs. P947, P1135, and gadoterate meglumine were injected into atherosclerotic apolipoprotein E-deficient and wild-type mice. The aortic MR imaging enhancement produced by the contrast agents was measured at different times and was compared by using one-way analysis of variance. MMP expression was investigated in the aortas by using MMP immunostaining and in situ MMP zymography. A fluorescent form of P947 (Eu-P947) was synthesized to compare the in vivo distribution of the contrast agent (Eu-P947) with specific MMP immunofluorescent staining.
MMP-targeted P947 facilitated a 93% increase (P < .001) in MR image signal intensity (contrast-to-noise ratio [CNR], 17.7 compared with 7.7; P < .001) of atherosclerotic lesions in vivo. Nontargeted P1135 (scrambled P947) provided 33% MR image enhancement (CNR, 10.8), whereas gadoterate meglumine provided 5% (CNR, 6.9). Confocal laser scanning microscopy demonstrated colocalization between fluorescent Eu-P947 and MMPs in atherosclerotic plaques. Eu-P947 was particularly present in the fibrous cap region of plaques.
P947 improved MR imaging for atherosclerosis through MMP-specific targeting. The results were validated and provide support for further assessment of P947 as a potential tool for the identification of unstable atherosclerosis.
评估P947（一种分子靶向基质金属蛋白酶（MMP）的磁共振（MR）成像造影剂）在体内辅助检测和成像动脉粥样硬化病变中MMP的能力；与P1135相比其特异性；MMP在动脉粥样硬化血管中的表达和分布；以及荧光铕（Eu）P947的体内分布和分子定位。
动物护理与使用委员会批准了所有实验。P947是通过将钆螯合物（1,4,7,10 - 四氮杂环十二烷 - N,N',N'',N'''- 四乙酸）连接到特异性结合MMP的肽上合成的。P947的 scrambled形式（P1135）是通过用缺乏结合MMP能力的 scrambled肽替换P947的靶向部分合成的。将P947、P1135和钆喷酸葡胺注入动脉粥样硬化载脂蛋白E缺陷型和野生型小鼠体内。在不同时间测量造影剂产生的主动脉MR成像增强，并使用单因素方差分析进行比较。通过MMP免疫染色和原位MMP酶谱分析研究主动脉中的MMP表达。合成了荧光形式的P947（Eu - P947），以比较造影剂（Eu - P947）的体内分布与特异性MMP免疫荧光染色。
靶向MMP的P947使体内动脉粥样硬化病变的MR图像信号强度增加了93%（P <.001）（对比噪声比[CNR]，从7.7增加到17.7；P <.001）。非靶向的P1135（scrambled P947）使MR图像增强了33%（CNR，10.8），而钆喷酸葡胺使增强了5%（CNR，6.9）。共聚焦激光扫描显微镜显示荧光Eu - P947与动脉粥样硬化斑块中的MMP共定位。Eu - P947特别存在于斑块的纤维帽区域。
P947通过MMP特异性靶向改善了动脉粥样硬化的MR成像。结果得到验证，并为进一步评估P947作为识别不稳定动脉粥样硬化的潜在工具提供了支持。
