PILOT PROJECT

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。我们研究的长期目标是了解动脉粥样硬化病变的血管化如何导致斑块不稳定和破裂。斑块血管化和斑块内出血与人动脉标本中的斑块破裂相关。以往的研究表明，基质金属蛋白酶（MMP）-9在组织缺血诱导的血管生成过程中起重要作用。在这项研究中，我们将专门研究MMP-9在动脉粥样硬化斑块血管化的作用，通过比较载脂蛋白E（apoE）基因敲除和apoE MMP-9双基因敲除小鼠颈动脉病变的血管生成。将使用颈动脉结扎法诱导病变。在病变诱导后14天和21天，使用CD 31、血管性血友病因子和平滑肌？的免疫组织化学方法，在结扎的颈动脉的冷冻切片中定量斑块血管生成。肌动蛋白。我们将通过用荧光微球灌注血管，然后用二甲苯提取来测量斑块微血管的功能灌注能力。我们也将使用荧光微血管造影术和共聚焦显微镜重建颈动脉病变内微血管的三维结构，以测量毛细血管分支点的数量。 我们期望观察到MMP-9缺陷动物的功能性灌注能力和毛细血管分支的缺陷。我们还希望将这项工作扩展到研究两种小鼠品系病变内血管生成微血管的跨毛细血管通透性，以确定血管生成过程中MMP依赖性的内皮基底膜降解是否可以改变斑块内大分子的转运。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The long-term goal of our research is to understand how vascularization of atherosclerotic lesions contributes to plaque destabilization and rupture. Plaque vascularization and intraplaque hemorrhage have been correlated with plaque rupture in human artery specimens. Previous studies have demonstrated that matrix metalloproteinase(MMP)-9 is important for capillary branching during angiogenesis induced by tissue ischemia. In this study, we will specifically examine the role of MMP-9 in the vascularization of atherosclerotic plaques by comparing angiogenesis in carotid artery lesions of apolipoprotein E (apoE) knockout and apoE MMP-9 double knockout mice. Lesions will be induced using the carotid ligation method. Plaque angiogenesis will be quantified in frozen sections of ligated carotid arteries 14 and 21 days after lesion induction using immunohistochemistry for CD31, von Willebrand factor, and smooth muscle ?-actin. We will measure functional perfusion capacity of the plaque microvasculature by perfusing the vessels with fluorescent microspheres followed by xylene extraction. We will also reconstruct the three-dimensional structure of the microvasculature within carotid artery lesions using fluorescence microangiography and confocal microscopy, in order to measure the number of capillary branch points. We expect to observe defects in both functional perfusion capacity and in capillary branching in MMP-9-deficient animals. We also hope to extend this work to examine transcapillary permeability of angiogenic microvessels within lesions in the two mouse strains, to determine whether MMP-dependent degradation of endothelial basement membranes during angiogenesis can alter macromolecular transport within the plaque.