HEMODYNAMICS AND MOLECULAR GENETIC RISK FACTORS IN ATHEROSCLEROSIS

动脉粥样硬化的早期病变，在人类受试者和 实验动物，总是以非随机的模式发育， 在动脉血管系统中，以及这些病变倾向的几何形状 面积~与分支点、曲率和其他区域相关 血液流动的改变 最近的研究表明， 生物力学力对表达的影响 内皮细胞（EC）的病理生理相关基因。 这使我们假设，血液动力学的力量，特别是 层流和扰动层流产生的壁面剪应力 流动，可以作为积极和消极的刺激， 动脉粥样硬化，通过对EC基因表达的影响。 为了验证这一 假设，我们提出了一系列相互关联的体外和体内 实验，利用细胞生物学，分子生物学， 生物学和实验病理学技术，三种以下 具体目标：在第一个具体目标，基于RT-PCR 差异显示将用于确定分子遗传学 在培养的EC中通过暴露于稳定的层流中而引起的程序 在“病变保护”中典型发生的剪切应力 区域，与“病变倾向”中发现的改变的剪切应力相比 地区 这些基因表达的差异模式， 在特别设计的模型系统中进行体外验证， 在培养的EC单层上产生扰动流场，以及 “动脉粥样硬化保护”和“动脉粥样硬化致病”的候选基因将被 根据结构和功能数据进行选择。 在第二 具体目标，已知的潜在协同作用或拮抗作用 生化危险因素（例如，氧化脂蛋白的成分， 例如溶血磷脂酰胆碱和升高水平的 高半胱氨酸），和抗动脉粥样硬化物质（例如，抗氧化剂） 将在体外模型中检查改变的剪切应力刺激。 在第三个具体目标中，候选人的表达方式 EC中的动脉粥样硬化保护基因和动脉粥样硬化致病基因将被 在受损伤保护和易损伤区域的体内检查 动脉粥样硬化易感者（ApoE缺乏和LDL 受体缺陷型）小鼠品系和人动脉标本。 一 病理生理学相关性的最终测试将尝试 研究转基因过表达的影响， 候选基因对病变定位/进展/消退的影响。 的 这些研究的结果应该增加我们对 生物力学和生物化学“危险因素”的相互作用 动脉粥样硬化，并可能导致关键EC的定义 基因参与。

The early lesions of atherosclerosis, in human subjects and experimental animals, consistently develop in a non-random pattern in the arterial vasculature, and the geometry of these ~lesion-prone areas~ correlates with branch points, curvatures and other regions of altered blood flow. Recent studies have demonstrated direct effects of biomechanical forces on the expression of pathophysiologically relevant genes by the endothelial cell (EC). This leads us to hypothesize that hemodynamic forces, in particular wall shear stresses generated by laminar and disturbed laminar flow, can function as both positive and negative stimuli in atherogenesis, via effects on EC gene expression. To test this hypothesis, we propose a series of interrelated in vitro and in vivo experiments, utilizing a combination of cell biological, molecular biological and experimental pathological techniques, under three Specific Aims: In the First Specific Aim, RT-PCR-based differential display will be used to define the molecular genetic programs elicited in cultured EC by exposure to the steady laminar shear stresses that characteristically occur in 'lesion-protected' areas, versus the altered shear stresses found in 'lesion-prone' areas. These differential patterns of gene expression then will be validated in vitro in a specially designed model system that generates a disturbed flow field over a cultured EC monolayer, and 'athero-protective' and 'athero-pathogenic' candidate genes will be selected, based on structural and functional data. In the Second Specific Aim, the potential synergism or antagonism of known biochemical risk factors (e.g., constituents of oxidized lipoproteins, such as lysophosphatidylcholine and elevated levels of homocysteine), and anti-atherogenic substances (e.g., antioxidants) with altered shear stress stimuli will be examined in vitro models. In the Third Specific Aim, the patterns of expression of candidate athero-protective and athero-pathogenic genes in EC will be examined in vivo in the lesion-protected and lesion-prone areas of the aorta of atherosclerosis-susceptible (ApoE-deficient and LDL receptor-deficient) mouse strains, and human arterial specimens. A final test of pathophysiological relevance will be attempted by examining the effects of transgenic overexpression of selected candidate genes on lesion localization/progression/regression. The results of these studies should increase our understanding of the interplay of biomechanical and biochemical 'risk factors' in atherogenesis, and may lead to the definition of the critical EC genes involved.