Effect of collagen fiber lipoidosis on the development of coronary atherosclerotic plaques in coronary heart disease

Abstract

Objective. To examine pathomorphological modifications of collagen fibers (CF) and some structural components of coronary atherosclerotic plaques (AP) in CHD and their role in the development of plaque instability and morphogenesis of atherosclerosis and evaluate pleiotropic effects of statins on stabilisation of AP. Materials and methods. Fndarterectomized segments of coronary arteries from 92 patients with CHD aged 55-73 years undergoing coronary bypass surgery. Collagen structures, lipids, macrophages and SMC were studied by histological and histochemical methods. Segments from 9 patients were examined under electron microscope. Computed morphometry of AP was performed in 85 AP in coronary arteries of 19 male patients with CHD and in 30 male andfemale patients on statins from 3 months to 3years and longer. Results. Lipoidosis of collagen fibers in coronary AP was observed in all CHD patients. It coincided with destruction of CF fibers, being a factor facilitating the development of plaque instability. Electron microscopy revealed accumulation of lipid masses between CF fibrils and destruction of these fibrils. Morphometrie analysis has revealed AP with varied degrees of stability. Vulnerability of unstable AP was determined by reduced number of stabilising structures, predominantly of collagen fibers, and depended to a lesser degree on lipid and macrophage contents. Structural changes in unstable AP under the effect of statins (decreased areas occupied by lipids and macrophages and increased area of CF) reflect pleiotropic effects of these drugs and indicate that they produce positive effects on “ the processes associated with lipid metabolism, vascular wall inflammation and extracellular matrix stabilisation.