Mineralization studies related to atherosclerosis

动脉粥样硬化钙化对动脉壁硬度有深远的影响，并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动脉粥样硬化中分离的囊泡可以启动钙化。 尚待确定的是：1）导致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）囊泡介导的钙化如何通过主动过程进行调节。 为了解决这些问题，本提案将重点关注以下具体目标：1）通过评价动脉粥样硬化形成过程中囊泡钙化先于主动脉钙化并随主动脉钙化逐渐增加的假设，支持囊泡在钙化中的作用。 在不同的时间段，将从对照和实验动物中分离主动脉囊泡，并比较其可钙化性。傅立叶变换光谱将用于表征类型和测量沉积在主动脉和分离的囊泡中的矿物质的量。 囊泡和动脉粥样硬化中沉积的矿物质的数量和类型的相似性强烈暗示囊泡在动脉粥样硬化钙化中。 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设。胆固醇及其衍生物、羟基胆固醇和脱氧胆酸盐去污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。 巨噬细胞产物如骨桥蛋白对囊泡钙化和肿瘤坏死因子（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中涉及的主动过程。 该项目的长期目标是确定引发和控制营养不良性钙化的因素，从而有助于预防和治疗动脉粥样硬化钙化的知识。

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.