Immunohistochemical and ultrasonic signs of the disturbance of anti-thrombogenic properties of endothelium in atherosclerosis of the carotid sinus

Introduction. Endothelial dysfunction is currently believed to play a crucial role in pathogenesis of atherosclerosis. Nevertheless, there are only few studies that demonstrate the relationship between changes in parameters of the atherosclerotic process and the main functional properties of endothelium. In addition, the findings are often controversial, which served as an incentive for this study.
Materials and methods. Thirteen atherosclerotic plaques resected during carotid endarterectomy were subjected to immunochemical and electron microscopy examination. The intensity of expression of the von Willebrand factor, thrombomodulin, and endothelial nitric acid synthase was assessed semi-quantitatively and compared to the main parameters of activity and the course of atherosclerosis in a plaque (volume of atheromatosis, lipophage aggregation, infiltration of the fibrous cap by monocytes and macrophages). Complicated and uncomplicated plaques were also compared.
Results. The level of von Willebrand factor in the carotid sinus endothelium increased as lipids were accumulated in it and as the fibrous cap was infiltrated by monocytes and macrophages (р<0.017), as opposed to the levels of thrombomodulin and endothelial nitric oxide synthase whose expression did not show the activity of the atherosclerotic process and did not correlate with the level of von Willebrand factor. Meanwhile, the expression of thrombomodulin and endothelial nitric oxide synthase correlated with each other (р=0.004). No difference in staining intensity for all three markers was detected between the complicated and uncomplicated plaques. Ultrasonic analysis of endothelium demonstrated the strongly pronounced disturbance of anti-thrombogenicity of the vascular wall as a result of numerous defects of the endothelial stratum, adhesion of blood cells to the arterial surface causing microthrombi formation and activation of endotheliocytes along with dystrophic changes in them, necrosis, and exfoliation into the vascular lumen.
Conclusions. The von Willebrand factor is found to have high diagnostic significance in the assessment of activity of the atherosclerotic process in the carotid sinus and the risk of developing complications. Thrombomodulin and endothelial nitric acid synthase are not recommended to be used as biomarkers of progression of atherosclerosis of this localization, since they are not indicative of the intensity of inflammatory response and destructive processes in a plaque.