MMP-8 and MMP-9 are associated with vulnerable, macrophage-rich carotid plaques, while MMP-2 is associated with stable, smooth muscle cell-rich plaques.
BACKGROUND AND PURPOSE: We studied matrix metalloproteinases (MMP) 2, 8, and 9 and extracellular matrix metalloproteinase inducer (EMMPRIN) levels in relation to carotid atherosclerotic plaque characteristics. METHODS: Carotid atherosclerotic plaques (n=150) were stained and analyzed for the presence of collagen, smooth muscle cell (SMC), and macrophages. Adjacent segments were used to isolate total protein to assess MMP-2 and MMP-9 activities and gelatin breakdown, MMP-8 activity, and EMMPRIN levels. RESULTS: Macrophage-rich lesions revealed higher MMP-8 and MMP-9 activities, whereas SMC-rich lesions showed higher MMP-2 activity. The levels of less glycosylated EMMPRIN-45kD were higher in SMC-rich lesions and lower in macrophage-rich plaques. EMMPRIN-45kD was associated with MMP-2 levels, whereas EMMPRIN-58kD was related to MMP-9 levels. CONCLUSIONS: MMP-2, MMP-8, and MMP-9 activities differed among carotid plaque phenotypes. Different EMMPRIN glycosylation forms are associated with either MMP-2 or MMP-9 activity, which suggests that EMMPRIN glycosylation may play a role in MMP regulation and plaque destabilization.
Sluijter et al. (Fri,) studied this question.