Mineralization studies related to atherosclerosis

动脉粥样硬化性钙化对动脉壁僵硬有深远的影响，与发病率和死亡率密切相关。然而，营养不良性钙化的机制仍不清楚。最近的一项体外研究表明，从动脉粥样硬化的人和兔的动脉中分离出的囊泡可以启动钙化。目前尚不清楚：1)引起动脉粥样硬化炎的高脂血症是否可以通过产生或激活可钙化的小泡促进钙化；2)小泡介导的钙化是如何通过一个活跃的过程来调节的。为了解决这些问题，本提案将集中于以下具体目标：1)通过评估在动脉粥样硬化形成过程中小泡的钙化能力先于并随着主动脉钙化而逐渐增加的假说，来支持小泡在钙化中的作用。在不同的时间段，从对照组和实验动物中分离出主动脉小泡，并比较它们的钙化程度。傅立叶变换光谱分析将被用来表征矿物质的类型，并测量在主动脉和分离的小泡中沉积的矿物质的数量。小泡和动脉中沉积的矿物质的数量和类型相似，这将强烈地表明小泡与动脉粥样硬化性钙化有关。2)验证囊泡介导的钙化受细胞、基质和囊泡成分密切调控的假说。胆固醇及其衍生物羟基胆固醇和脱氧胆酸盐洗涤剂已知可刺激细胞和囊泡介导的钙化，将用于研究高脂血症导致钙化的机制。为了更好地了解囊泡介导的钙化过程中的活性过程，将研究骨桥蛋白等巨噬细胞产物对囊泡钙化和肿瘤坏死因子(TNF-α)在钙化小泡发病机制中的作用。该项目的一个长期目标是确定启动和控制营养不良钙化的因素，从而有助于了解可能导致预防和治疗动脉粥样硬化性钙化的知识。

Atherosclerotic calcification has profound effects on arterial wall rigidity and is closely associated with morbidity and mortality. However, the mechanisms of dystrophic calcification remain poorly understood. A recent in vitro study demonstrated that vesicles isolated from atherosclerotic human and rabbit aortas can initiate calcification. It remains to be established: 1) whether hyperlipidemia, which causes atherosclerotis, can promote calcification through the production or activation of calcifiable vesicles and 2) how vesicle-mediated calcification is regulated through an active process. To address these issues, the present proposal will focus on the following Specific Aims: 1) To support the role of vesicles in calcification by evaluating the hypothesis that calcifiability of vesicles precedes and progressively increases with aortic calcification during atherogenesis. At different periods of time, aortic vesicles will be isolated from the control and experimental animals and compared for their calcifiability. Fourier transform spectroscopy will be used to characterize the types and to measure the amount of mineral deposited in aorta and by isolated vesicles. A similarity in the amounts and types of mineral deposited by vesicles and in aortas would strongly implicate vesicles in atherosclerotic calcification. 2) To test the hypothesis that vesicle-mediated calcification is closely regulated by cellular, matrix, and vesicle constituents. Cholesterol and its derivatives hydroxycholesterol and deoxycholate detergent known to stimulate cell- and vesicle- mediated calcification will be used to study the mechanisms whereby hyperlipidemia can lead to calcification. The effects of macrophage products such as osteopontin on vesicle calcification and tumor necrosis factor (TNF-alpha) on pathogenesis of calcifying vesicles will be investigated for a better understanding of the active process involved in vesicle-mediated calcification. A long-term goal of the project is to identify factors that initiate and control dystrophic calcification, thereby contributing to the knowledge that may lead to the prevention and treatment of atherosclerotic calcification.