Expression and significance of integrin α5β1 and fibronectin in atherosclerotic plaques from autopsy specimens

Abstract

Objective: To investigate the expression of integrin α5β1 and fibronectin in the human aorta and coronary artery, and their effects in the development of atherosclerosis. Methods: One hundred and twenty autopsy aorta and coronary artery specimens were collected, and the expression of CD68, actin, integrin α5β1 and fibronectin was detected by immunohistochemical staining. Atherosclerotic plaques were located by CD68 and actin staining, and the degree of coronary artery stenosis was determined by elastic fiber staining and NIH Scion Image(60.1) software. The coronary artery tissues were divided into groups A (0-25%); B (26%-50%); C (51%-75%) and D (76%-100%) according to the degree of stenosis. Results: Integrin α5β1 showed cytoplasmic expression in endothelium, foam cells, monocytes, smooth muscle cells and adjacent tissue around calcification. In both the aorta and coronary artery, integrin α5β1 expression was stronger in the smooth muscle cells in the internal elastic lamina than in the tunica. The expression intensity in coronary artery smooth muscle decreased with increasing degree of coronary artery stenosis. Fibronectin showed cytoplasmic expression in foam cells, monocytes, smooth muscle cells of the internal elastic lamina and adjacent tissue around calcification. There was positive correlation of fibronectin and integrin α5β1 expression in smooth muscle cells and adjacent tissue around calcification. Conclusions: In the development of atherosclerosis, integrin α5β1 and fibronectin may participate in the regulating the migration of smooth muscle cells to the intima, and promote the formation of local calcification of atherosclerotic plaques. But integrin α5β1 is not involved in the late stage of atherosclerosis with increasing coronary artery stenosis.