Mineralization studies related to atherosclerosis

动脉粥样硬化性钙化对动脉壁硬度有深远的影响，与发病率和死亡率密切相关。然而，营养不良钙化的机制仍然知之甚少。最近的一项体外研究表明，从动脉粥样硬化的人和兔主动脉中分离的小泡可以启动钙化。1)引起动脉粥样硬化的高脂血症是否可以通过可钙化囊泡的产生或激活来促进钙化，2)囊泡介导的钙化是如何通过一个活跃的过程来调节的，这些还有待确定。为了解决这些问题，本提案将关注以下具体目标：1)通过评估在动脉粥样硬化过程中，囊泡的可钙化性先于并随着主动脉钙化而逐渐增加的假设，来支持囊泡在钙化中的作用。在不同时期，从对照动物和实验动物身上分离主动脉囊泡，比较其钙化性。傅里叶变换光谱将用于表征类型和测量矿物沉积在主动脉和孤立的囊泡的数量。在囊泡和主动脉中沉积的矿物质的数量和类型上的相似性强烈暗示了动脉粥样硬化钙化中的囊泡。2)验证囊泡介导的钙化受细胞、基质和囊泡成分密切调节的假设。胆固醇及其衍生物羟基胆固醇和脱氧胆酸盐洗涤剂已知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。巨噬细胞产物如骨桥蛋白对囊泡钙化的影响以及肿瘤坏死因子（tnf - α）对钙化囊泡发病机制的影响将被研究，以更好地了解囊泡介导的钙化所涉及的活性过程。该项目的长期目标是确定启动和控制营养不良钙化的因素，从而有助于预防和治疗动脉粥样硬化性钙化。

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.