Macromolecular Structure of Arterial Walls

动脉壁和动脉瓣膜是复杂的大分子结构。这些结构的主要元素之一是支架，它提供了完成手头任务的力量和灵活性，要么保持血管中的血液对抗动脉压，要么通过冠状动脉瓣膜的功能维持压力。在过去的几年里，很明显，这些大分子的实际微观结构和组成可以影响不同疾病状态的进展，最明显的是动脉粥样硬化和钙化。为了更好地了解这一过程，我们开始研究动脉血管床中大分子的精细结构，使用一种新的光学成像技术，该技术依赖于胶原和弹性蛋白的非线性激发(NLE)，在未固定的新鲜样品中提供其结构的亚微米图像，并使用荧光显微镜和传统组织学方法直接测量低密度脂蛋白(LDL)结合。这些研究已经确定核心蛋白和大聚糖是瓣膜小叶和肾口低密度脂蛋白的主要结合部位。基于核心蛋白聚糖/双聚糖和低密度脂蛋白相互作用部位的相对浓度，我们决定以低密度脂蛋白的静电结合部位为靶点，以评估这种相互作用在动脉粥样硬化进展中的干扰作用。对低密度脂蛋白赖氨酸氨基酸残基以及模型分子如硫酸肝素的特定修饰已经证明，通过在特殊设计的体外分析中显著抑制低密度脂蛋白与核心蛋白的结合，这一策略是可行的。其中一个主要问题是寻找与低密度脂蛋白结合活性最低的高亲和力分子。目前，我们正在与行业合作伙伴合作，评估其他试图阻止低密度脂蛋白-核心蛋白相互作用的候选分子。如果在体外成功发现高亲和力抑制剂，我们将启动易患动脉粥样硬化的转基因小鼠模型的研究。考虑到这一目标，我们已经开始了对正常和易患动脉粥样硬化的转基因小鼠的研究，以使用NLE显微镜来关联动脉大分子结构的发展。此外，CARS显微镜直接观察脂肪酸C-H键也将被用来完成对该动物模型动脉粥样硬化性疾病发展的微创评价。这项研究完成后，将对哺乳动物模型中动脉壁大分子结构的发展进行深入分析，并为采用不同策略减少动脉粥样硬化的慢性研究奠定基础。

The arterial wall and arterial valves are complex macromolecular structures. One of the major elements of these structures is the scaffold that provides the strength and flexibility to perform the task in hand either retaining the blood in vessels against the arterial pressure or maintaining pressure via the function of coronary valves. In the last several years it has become apparent that the actual microstructure and composition of these macromolecules could influence the progress of different disease states most notably atherosclerosis and value calcification. To gain a better understanding of this process, we have embarked on studies to understand the fine structure of the macromolecules in arterial vascular bed using a novel optical imaging technique that relies on the non-linear excitation (NLE) of collagen and elastin to provide sub-micron images of their structure in unfixed fresh samples together with direct measures of low density lipoprotein particles (LDL) binding using fluorescence microscopy and conventional histology methods. These studies have identified decorin and biglycan as the major binding sites for LDL in the valve leaflet and renal ostia. Based on the relative concentration of the interaction sites of decorin/biglycan and LDL, we have decided to target the LDL electrostatic binding sites to evaluate the interference of this interaction in the progression of atherosclerosis. Specific modification of the LDL lysine amino acid residues as well as model molecules such as Heparin sulfate has demonstrated that this strategy is feasible by significantly inhibiting LDL association with decorin in specially designed in vitro assays. One of the major issues is to find molecules with high affinity to the LDL sites with minimum off target activity. Currently we are working with industry partners to evaluate other candidate molecules for attempting to block the LDL-decorin interaction. If successful finding high affinity inhibitors, in vitro, we will initiate studies in the atherosclerotic prone transgenic mouse models. With this goal in mind, we have initiated studies in normal and atherosclerosis prone transgenic mice to correlate the development of the arterial macromolecular structures using NLE microscopy. In addition, CARS microscopy directly observing the fatty acid C-H bonds will also be used to complete the minimally invasive approach evaluation of the development of atherosclerotic disease in this animal model. This study when completed will provide an in depth analysis of the development of the macromolecular structures of the arterial wall in a mammalian model and permit the background for chronic studies with different strategies to reduce atherosclerosis.