We performed a complex morphological study of samples of different types of unstable atherosclerotic plaques obtained from 33 men with occlusive coronary atherosclerosis, who underwent coronary artery endarterectomy during coronary artery bypass surgery. In the samples, expression of MMP-2 and MMP-9, collagen IV, CD31, CD34, factor VIII, and actin of smooth muscle cells was evaluated by morphometric and immunohistochemical methods. The maximum expression of MMP-9 was found in unstable plaques of the lipid type, where it 1.4- and 1.24-fold surpassed the corresponding levels in plaques of the inflammatory-erosive and degenerative-necrotic types. Unstable plaques of the degenerative-necrotic type are characterized by the most intensive expression of collagen IV in comparison with plaques of the inflammatory-erosive and lipid types (by 2.8 and 2.2 times, respectively). The maximum neovascularization was detected in inflammatory-erosive plaques, which was confirmed by enhanced expression of CD31 and CD34 markers in comparison with plaques of the lipid (by 7.6 and 18.95 times, respectively) and degenerative-necrotic (by 31.1 and 39.8 times) types.
Keywords: atherosclerosis; immunohistochemistry; metalloproteinases; neovascularization; unstable plaque.