The expression of glycophorin A and osteoprotegerin is locally increased in carotid atherosclerotic lesions of symptomatic compared to asymptomatic patients

Abstract

The aim of this study was to evaluate in detail the histopathological characteristics of endarterectomized carotid atherosclerotic lesions in symptomatic versus asymptomatic patients. Twenty carotid lesions, 10 from asymptomatic and 10 from symptomatic patients who underwent carotid endarterectomy were classified according to histomorphological features. Samples were analyzed for intraplaque localization and for the expression of proteins associated with inflammation, such as CD68, interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), pentraxin-3 (PTX-3), nuclear factor-κB (NF-κB), C-reactive protein (CRP) and transforming growth factor-β (TGF-β), as well as for proteins associated with vascular remodelling, such as matrix-metalloproteinase-9 (MMP-9), glycophorin A (GYPA), osteoprotegerin (OPG), vascular cell adhesion molecule-1 (VCAM-1), endothelin-1 (ET-1), vascular endothelial growth factor (VEGF) and vascular smooth muscle cell actin (VSMA). Corresponding expression scores were compared between the symptomatic and asymptomatic patients and evaluated statistically. The expression of all 14 evaluated markers was significantly elevated in the border zone adjacent to the mixed plaque compared with the unaffected control area of the same sample (p<0,016). The expression scores of GYPA and OPG were significantly higher in the border zones around the calcified (GYPA, p=0.035; OPG, p=0.043) and mixed (GYPA, p<0.001; OPG, p=0.007) plaque zones of symptomatic patients compared to asymptomatic patients. No difference in expression scores was observed for any of the analyzed inflammatory marker proteins between the border zones of symptomatic and asymptomatic patients. In conclusion, the increased expression of GYPA, indicating intraplaque hemorrhage, and OPG, indicating the transdifferentiation of vascular cells, in carotid atherosclerotic lesions may be associated with an increased risk of plaque instability.