Mechanism of arterial calcification: Role of matrix metalloproteinases

目的：当前糖尿病/透析患者的增加增加了动脉钙化缺血性疾病治疗的机会。在本研究中，我们探讨了糖尿病/透析患者动脉钙化的机制和动物模型，以及基质金属蛋白酶在动脉钙化中的作用。材料与方法：研究期间，从12例因肢体缺血而行静脉分流术3-10个月后行静脉移植狭窄改良手术的糖尿病/透析患者中获取人静脉移植标本，从40周龄的老年糖尿病大鼠（Otsuka Long Evans Tokushima Fatty大鼠；OLETF大鼠）中获取动物主动脉标本，保存于细胞banner中供后期分析。对所有标本进行横切，通过光镜和扫描电镜对钙化微斑进行筛选；扫描电镜观察到钙化微斑后，用电镜电探针分析（EPMA）确定钙化，并进行免疫组化处理。免疫组化检测骨钙素、MMC-3、-9、13。确认后，用透射电镜评价钙化斑与周围组织的关系。结果：扫描电镜显示，在所有人静脉移植物和大鼠主动脉的基质中有许多大小不等的微斑，EPMA显示斑点中存在磷和钙，探测微斑是否钙化。在糖尿病/透析患者的人静脉移植中，微钙化在植入后3个月内开始。免疫组织化学显示MMPs和骨钙素的表达，但与动脉钙化起始机制的详细关系尚不清楚。透射电镜显示，钙化斑点直径70 ~ 300 nm，位于细胞外基质中。进一步放大显示钙化由直径为10nm的纳米颗粒聚集组成。结论：动脉钙化形成细胞外基质，形成直径为10nm的颗粒聚集。钙化的发生与骨钙素、骨基质蛋白酶等基因表达的关系尚不清楚。少

OBJECTIVES: Current increase of patients with diabetes/dialysis increases opportunities of management of ischemic diseases with calcified arteries. In the present study, we investigated the mechanism of arterial calcification in diabetic/dialysis patients as well as animal model, and a role of matrix metalloproteinases in arterial calcification.MATERIAL AND METHOD : During the study period, human vein graft specimens were obtained from 12 patients with diabetes/dialysis who underwent revised surgery for vein graft stenosis 3-10 months after the initial vein bypasses for limb ischemia, and animal aortic specimens were obtained from old diabetic rats (Otsuka Long Evans Tokushima Fatty rat; OLETF rat) with age of 40 weeks, and were stored in cell baner for later analysis. All of the specimens were cross-sectioned, and calcification microspots were screened by light microscopy and SEM; when calcified microspots were identified by SEM, the specimens were analyzed by the electroprobe microan … More alysis (EPMA) for confirmation of calcification, and were also subjected to immunohistochemistry. In immunohistochemistry, osteocalcin and MMC-3,-9, and-13 were examined. After the confirmation, the calcification spots was subjected to TEM to evaluate relation to the surrounding tissue.RESULTS : The SEM demonstrated many various sized microspots in the media in all human vein grafts as well as rat aortas, and EPMA demonstrated the presense of phosphorus and calcium in the spots, probing the microspots to be calcification. In human vein grafts in diabetic/ dialysis patients, microcalcification initiates within 3 months after implantation.Immunohistochemistry demonstrated the expression of MMPs as well as osteocalcin, but the detail relationship to the initiation mechanism of arterial calcification remained unclear. TEM showed calcification spots were with diameters of 70-300 nm, and located in extracellular matrix. Further magnification disclosed the calcification consisted of an aggreigation of nanoparticles with a diameter of 10nm.CONCLUSION : Arterial calcification develops extracellular matrix in media, and forms aggregation with a diameter of 10 nm particles. Relation between development of calcification and gene expressions such as MMPs and osteocalcin still remained unclear. Less