Matrix Metalloproteinase 2 Is Associated With Stable and Matrix Metalloproteinases 8 and 9 With Vulnerable Carotid Atherosclerotic Lesions

Abstract

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 (nϭ150) 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. Key Words: atherosclerosis Ⅲ carotid arteries Ⅲ carotid artery plaque Ⅲ endarterectomy Ⅲ inflammation Ⅲ matrix metalloproteinases A therosclerosis is characterized by remodeling of the extracellular matrix and the accumulation of lipids and inflammatory cells. 1 Advanced stable atherosclerotic plaques are rich in collagen and smooth muscle cells (SMCs), whereas a large lipid core covered by a thin fibrous cap with a dense inflammatory infiltrate characterizes unstable and ruptured plaques. 2 Increased expressions of matrix metalloproteinases (MMPs) 1, 2, 3, 7, 8, 9, and 13 are found in macrophages and in SMCs covering the shoulder regions of atherosclerotic plaques. 3 Extracellular MMP inducer (EMMPRIN) stimulates the production of different MMPs. 4 EMMPRIN has been identified in human macrophage-rich atheroma. 5 However, the relation of EMMPRIN with plaque characteristics and MMP expression remains to be elucidated. In the present study, carotid endarterectomy plaque characteristics were associated with MMP-2, MMP-8, and MMP-9 activities and EMMPRIN expression levels. MethodsAthero-Express is an ongoing multicenter study in which carotid atherosclerotic specimen are obtained from patients undergoing endarterectomy. 6 Segments of the culprit lesion of each plaque were studied semiquantitatively for collagen content, SMCs, and macrophages and classified as no/minor or moderately/heavily stained. Moreover, an overall plaque phenotype was assigned to each lesion based on overall appearance.The adjacent segment was used to isolate total protein and MMP-2, MMP-8, and MMP-9. Total MMP activities were measured using the Biotrak activity assays RPN2631, RPN2635, and RPN2634, respectively (Amersham Biosciences). To determine pro-and active MMP-2 and MMP-9 levels in each plaque, zymography was performed as described elsewhere. 7 EMMPRIN expression levels were determined by Western blotting (sc-9753, Santa Cruz Bi...

Levels of extra domain A containing fibronectin in human atherosclerotic plaques are associated with a stable plaque phenotype

“…These smooth muscle cells produce next to fibronectin containing EDA [2,3] also collagen [32] and other matrix molecules for repair of the arterial wall. This is in agreement with the previously observed correlations between EDA, collagen content, MMP2 and Emmprin 45 kDa levels [27] in the plaque. SMC proliferation and their production of ECM components may stabilize or reorganize the plaques from unstable into more stable atherosclerotic lesions.…”

“…Previously, smooth muscle cell rich, stable lesions were associated with high Emmprin 45 kDa and MMP-2 levels. In contrast, unstable inflammatory lesions were associated with Emmprin 58 kDa and MMP-9 levels [27]. The expression of 45 kDa variant of MMP inducer Emmprin was positively correlated with EDA in the plaque, while the 58 kDa variant showed a trend to correlation with EDA (45 kDa, P < 0.001; 58 kDa, P = 0.072).…”

“…MMP-8 has been related with thrombus formation. Recently we demonstrated an increase of MMP-8 and MMP-9 activity levels in unstable plaques, whereas MMP-2 activity levels are higher in stable lesions [27].…”

“…Extracellular matrix metalloproteinase inducer (Emmprin) expression levels were determined by Western blotting [27] (sc-9753, Santa Cruz Biotechnology).…”

Blockade of Ets-1 attenuates epidermal growth factor-dependent collagen loss in human carotid plaque smooth muscle cells

“…Recently, we have reported increased expression of MMP-1 and MMP-9 and decreased expression of collagen type I and III in VSMCs isolated from S plaques compared with AS plaques, supporting the role of collagen in plaque stability. These results are in agreement with similar studies (45,50,53). However, the molecular mechanism of MMP activation in S plaques is poorly understood.…”