Role of Inflammation in Atherosclerosis
Immunohistochemical and Electron Microscopic Images of a Coronary Endarterectomy Specimen
A 60-year-old man with triple-vessel coronary artery disease was admitted for coronary artery bypass grafting. An endarterectomy of the left anterior descending coronary artery was needed to achieve revascularization. The endarterectomized plaque was subjected to light and electron microscopic examination, including immunohistochemistry for smooth muscle actin and macrophage marker CD 68. The images (Figure 1 through Figure 4⇓⇓⇓) show very graphically the inflammatory component of the atherosclerotic process, including “neovessel” formation, macrophage concentration, and active diapedesis and emigration of the macrophages through the endothelial gap junction of the neovessels into the interstitium, especially in the “shoulder” region. The sinusoidal nature of these vessels is clearly demonstrated. The endothelial lining of these vessels has increased expression of adhesion molecules1 and provides an alternative entry pathway for macrophages, in addition to that coming across the endothelium of the main arterial lumen.2
O’Brien K, McDonald T, Chait A, Allen M, Alpers C. Neovascular expression of E-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 in human atherosclerosis and their relation to intimal leukocyte content. Circulation. 1996; 93: 672–682.
Davies MJ. Atlas of Coronary Artery Disease. Philadelphia, Pa: Lippincott-Raven; 1998: 48.