Summary
Plaque rupture underlies most myocardial infarctions. Plaques vulnerable to rupture
have thin fibrous caps, an excess of macrophages over vascular smooth muscle cells,
large lipid cores, and depletion of collagen and other matrix proteins form the cap
and lipid core. Production of matrix metalloproteinases from macrophages is prominent
in human plaques, and studies in genetically modified mice imply a causative role
for metallopro teinases in plaque vulnerability. Recent in-vitro studies on human
monocyte-derived macrophages and on foam-cell macrophages generated in vivo suggest the existence of several macrophage phenotypes with distinct patterns of
metalloproteinase expression. These phenotypes could play differing roles in cap,
core and aneurysm formation.
Keywords
Atherosclerosis - atherothrombosis - extracellular matrix - inflammation - matrix
metalloproteinases