To determine the involvement of the non-
receptor tyrosine kinase cSrc in plaque destabilization in
carotid atherosclerosis (CAS), which is responsible for
cerebral infarction, we performed quantitative and morphological detection of phosphorylated active cSrc (p-cSrc) and histopathological examination in CAS lesions. We examined
carotid endarterectomy specimens obtained from 32 CAS patients. Each specimen was used for immunoblot and immunohistochemical analyses of p-cSrc, histopathological analysis, and image analysis of macrophage content. There was a strong positive correlation between cSrc activation on blots and macrophage content on sections. When we defined the macrophage-rich plaque (MRP) and the macrophage-poor plaque (MPP) as having macrophage content more and less than 5%, respectively, the p-cSrc density and the occurrence of plaque
hemorrhage and
thrombus formation were significantly increased in the MRP group (n=18) compared to the MPP group (n=14). p-cSrc immunoreactivity was localized in lesional endothelial cells, macrophages, and smooth muscle cells, which contained proinflammatory substances: the upstream
oxidized low density lipoprotein,
tissue factor and
osteopontin, and the downstream active forms of extracellular signal-activated
kinase and p38 and
nuclear factor-kappaB. Our results suggest that cSrc activation in lesional cells contributes to plaque destabilization in CAS via persistent
inflammation.