Expression of osteopontin in calcified coronary atherosclerotic plaques

Advanced atherosclerosis is often associated with dystrophic calcification and remodeling of extracellular matrix of vascular wall. Recently many stud ies have documented a general relationship between calcification and severi ty of coronary disease, and discussed the feasibility of electron beam comp uted tomography for detecting and quantifying the coronary artery calcifica tion in the patients. The present study investigated the expression and the localization of osteopontin, one of noncollagenous bone matrix protein, wi thin the calcified coronary arteries. Autopsy-derived coronary artery speci mens were scanned and reconstructed to visualize the pattern of coronary ca lcification using a novel microscopic computed tomography technique. The lo calization of the osteopontin were evaluated by immunohistochemial stain wi th LF7. The present study showed that the pattern of coronary calcification is variable and the expression of osteopontin is localized mainly to calci fied lesion. The smooth muscle cells in addition to macrophage expressed os teopontin protein in human coronary atherosclerotic plaques. Soluble osteop ontin released near to the sites of vascular calcification may represent an adaptive mechanism aimed at regulating the process of vascular calcificati on.