Matrix vesicles in atherosclerotic calcification.

Matrix vesicles, small extracellular membranous structures, are known to be the initial loci of calcification of cartilage, bone, and dentin. Calcification is an important complication of atherosclerosis. Using histologic, ultrastructural, and cytochemical techniques, the present study has demonstrated that matrix vesicle-like structures are involved in the calcification of atherosclerotic lesions, as well as in arterial medial calcification. In aortas from autopsied humans and from rabbits and chickens on atherogenic diets, the matrix vesicles appear to be derived from intimal and medial cellular components, mainly smooth muscle cells.