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(Arteriosclerosis, Thrombosis, and Vascular Biology. 2006;26:2181.)
© 2006 American Heart Association, Inc.

Editorials

Perplexity of Plaque Proteinases

Peter Libby

From the Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Mass.

Correspondence to Peter Libby, Division of Cardiovascular Medicine, Department of Medicine, and the Donald W. Reynolds Cardiovascular Clinical Research Center, Brigham and Women’s Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115. E-mail plibby@rics.bwh.harvard.edu

An extract of the first 250 words of the full text is provided, because this article has no abstract.

Cells found in atherosclerotic plaques express matrix metalloproteinases (MMPs). Human atheromata contain a broad array of proteases (Table 1) and their endogenous inhibitors. Altered balance between proteinases and their inhibitors may participate in a number of biological processes important in the clinical manifestations of atherosclerosis.¹ For example, matrix remodeling must occur during compensatory enlargement, arterial aneurysm formation, angiogenesis, desquamation of endothelial cells that accompanies superficial erosion, and the weakening of the atherosclerotic plaque’s fibrous cap that presumably renders it prone to rupture and hence thrombosis.

View this table: [in this window] [in a new window]   TABLE 1. Examples of the Plethora of Proteinases in Atherosclerotic Plaques

See page 2351

In this issue of Arteriosclerosis, Thrombosis, and Vascular Biology, Choudhary et al confirm the presence of MMP gelatinases and highlight the heterogeneity of MMP distribution in human carotid endarterectomy specimens.² They show differential expression of 2 prototypical MMP gelatinases, MMP-2 and -9. Many normal carotid segments contain more MMP-2 than MMP-9. More complex lesions tended to have more MMP-9 than MMP-2. As normal arteries contain substantial medial pro–MMP-2 (the inactive zymogen form; Figure), this finding is expected.^3,4 Likewise, MMP-9 overexpression in human plaques generally localizes to macrophages, explaining why the more advanced lesions may have disclosed higher levels of this MMP. The sophisticated analysis presented by Choudhary et al may then reflect the cellular content of lesions of different types and in different regions within a given endarterectomy specimen, an issue not addressed in their study.

View larger version (35K): [in this window] [in a new window]   Atherogenic risk factors including oxidized LDL and angiotensin II result in . . . [Full Text of this Article]

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Quantitation and Localization of Matrix Metalloproteinases and Their Inhibitors in Human Carotid Endarterectomy Tissues

Salman Choudhary, Catherine L. Higgins, Iou Yih Chen, Michael Reardon, Gerald Lawrie, G. Wesley Vick, III, Christof Karmonik, David P. Via, and Joel D. Morrisett
Arterioscler Thromb Vasc Biol 2006 26: 2351-2358. [Abstract] [Full Text] [PDF]