Vascular endothelial cadherin expression in human carotid atherosclerotic plaque and its relationship with plaque morphology and clinical data

Objectives. To determine the relationship between Vascular Endothelial (VE)-cadherin expression in carotid plaques, carotid plaque morphology and clinical findings of carotid disease. Materials and methods. Fifty-three formalin-fixed, paraffin embedded specimens of human carotid atherosclerotic plaque obtained by endarterectomy and 20 normal postmortem arteries (control group) were studied. Thirty patients were symptomatic and 23 asymptomatic. The expression of VE-cadherin was examined by an avidin-biotin immunoperoxidase technique using specific monoclonal antibodies against this molecule. We used a scale for the estimation of the expression of the VE-cadherin, in which negative expression was indicated by 0, weak expression by 1, and strong expression by 2. In serial sections we also determined the cellular phenotype of atherosclerotic plaques: i.e. the endothelial cells (F8), macrophage (CD68) and smooth muscle cells. Possible relations between variables in statistical analysis were examined by the chi-square test or Fisher's exact test. Results. Expression of VE-cadherin was observed in small newly established vessels, particularly in areas with intense inflammatory infiltrations by macrophages and leucocytes. A strong expression of VE-cadherin was evident particularly in symptomatic instead in asymptomatic patients (43% vs. 13%, p = 0.057), in high degree stenosis group (81% vs. 0%, p = 0.005), and in patients with ischaemic infarct in brain scan (71% vs. 23%, p = 0.021). On the other hand, there was no relation between molecule expression and plaque ultrasonic characteristics (echogenic or echolucent, p = 0.499). Finally, there was a significant statistical correlation in the expression of VE-cadherin and the histological type of the plaque, namely fibrotic and complicated plaques. Strong VE-cadherin expression was observed in 64% of complicated plaques instead of 6.5% in fibrotic plaques (p = 0.001). Conclusion. An intense expression of VE-cadherin in carotid plaques is linked with plaque instability, high degree of stenosis and clinical events. This molecule seems to be a marker of progression of the atherosclerotic plaque.