| Budget Amount *help |
¥13,800,000 (Direct Cost: ¥13,800,000)
Fiscal Year 2006: ¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 2005: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥6,300,000 (Direct Cost: ¥6,300,000)
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| Research Abstract |
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
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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
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