Macromolecular Structure of Arterial Walls

动脉壁和动脉瓣是复杂的大分子结构。这些结构的主要元素之一是支架，它提供了强度和灵活性来执行手头的任务，或者在动脉压力下保持血管中的血液，或者通过冠状动脉瓣膜的功能维持压力。在过去的几年里，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价值钙化。为了更好地理解这一过程，我们已经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，该技术依赖于胶原蛋白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常规组织学方法直接测量低密度脂蛋白颗粒（LDL）的结合。这些研究已经确定了decorin和biglycan是瓣膜小叶和肾口LDL的主要结合位点。基于decorin/biglycan与LDL相互作用位点的相对浓度，我们决定以LDL静电结合位点为目标，评估这种相互作用对动脉粥样硬化进展的干扰。对LDL赖氨酸氨基酸残基以及硫酸肝素等模型分子进行特异性修饰，通过在专门设计的体外实验中显著抑制LDL与decorin的关联，证明了该策略是可行的。其中一个主要问题是找到与低密度脂蛋白位点高亲和力的分子，并使其脱靶活性最小。目前，我们正在与行业合作伙伴一起评估其他候选分子，以试图阻断LDL-decorin相互作用。如果成功地在体外找到高亲和力的抑制剂，我们将开始在动脉粥样硬化易感性转基因小鼠模型中进行研究。考虑到这一目标，我们已经开始在正常和动脉粥样硬化易感转基因小鼠中进行研究，使用NLE显微镜来关联动脉大分子结构的发展。此外，CARS显微镜下直接观察脂肪酸C-H键也将用于完成该动物模型动脉粥样硬化疾病发展的微创入路评估。这项研究一旦完成，将为哺乳动物模型中动脉壁大分子结构的发展提供深入的分析，并为采用不同策略减少动脉粥样硬化的慢性研究提供背景。

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.