Inflammatory Biomarkers in Atherosclerosis: Pentraxin 3 Can Become a Novel Marker of Plaque Vulnerability

Abstract

Inflammation is crucially involved in the development of carotid plaques. We examined the relationship between plaque vulnerability and inflammatory biomarkers using intraoperative blood and tissue specimens. We examined 58 patients with carotid stenosis. Following carotid plaque magnetic resonance imaging, 41 patients underwent carotid artery stenting (CAS) and 17 underwent carotid endarterectomy (CEA). Blood samples were obtained from the femoral artery (systemic) and common carotid artery immediately before and after CAS (local). Seventeen resected CEA tissue samples were embedded in paraffin, and histopathological and immunohistochemical analyses for IL-6, IL-10, E-selectin, adiponectin, and pentraxin 3 (PTX3) were performed. Serum levels of IL-6, IL-1β, IL-10, TNFα, E-selectin, VCAM-1, adiponectin, hs-CRP, and PTX3 were measured by multiplex bead array system and ELISA. CAS-treated patients were classified as stable plaques (n = 21) and vulnerable plaques (n = 20). The vulnerable group showed upregulation of the proinflammatory cytokines (IL-6 and TNFα), endothelial activation markers (E-selectin and VCAM-1), and inflammation markers (hs-CRP and PTX3) and downregulation of the anti-inflammatory markers (adiponectin and IL-10). PTX3 levels in both systemic and intracarotid samples before and after CAS were higher in the vulnerable group than in the stable group. Immunohistochemical analysis demonstrated that IL-6 was localized to inflammatory cells in the vulnerable plaques, and PTX3 was observed in the endothelial and perivascular cells. Our findings reveal that carotid plaque vulnerability is modulated by the upregulation and downregulation of proinflammatory and anti-inflammatory factors, respectively. PTX3 may thus be a potential predictive marker of plaque vulnerability.