Activation of metalloproteinase-2, loss of matrix scleroprotein content and coronary artery calcification.

Plaques from the coronary arteries of explanted hearts showed massive calcification (15-fold increase) with a loss of scleroproteins (-36%), an increase in the collagen to elastin ratio (twofold) and activation (+15%) of matrix metalloproteinase-2 (MMP-2). Plaque-free portions of the coronary artery gave results similar to those obtained with the internal mammary artery. There was a significant correlation between plaque calcification and MMP-2 activation, suggesting that the two processes may be linked.