Vascular smooth muscle cells and calcification in atherosclerosis

Vascular calcification is a prominent feature of atherosclerosis but the mechanisms underlying vascular calcification are still obscure. Since bone-associated proteins such as osteonectin, osteocalcin, and matrix Gla protein have been detected in calcified vascular tissues, calcification has been considered to be an organized, regulated process similar to mineralization in bone tissue. Vascular smooth muscle cells (VSMCs) are currently considered to be responsible for the formation of vascular calcifications. Apoptosis of VSMCs appears to be a key factor in this process, while other factors including cell-cell interactions (macrophages and VSMCs), lipids, and plasma inorganic phosphate levels modulate the calcification process. The focus of this review is on the role of VSMCs in the development of calcifications in atherosclerotic plaques.