Feasibility of ex vivo fluorescence imaging of angiogenesis in (non-) culprit human carotid atherosclerotic plaques using bevacizumab-800CW

Abstract

Vascular endothelial growth factor-A (VEGF-A) is assumed to play a crucial role in the development and rupture of vulnerable plaques in the atherosclerotic process. We used a VEGF-A targeted fluorescent antibody (bevacizumab-IRDye800CW [bevacizumab-800CW]) to image and visualize the distribution of VEGF-A in (non-)culprit carotid plaques ex vivo. Freshly endarterectomized human plaques ( n = 15) were incubated in bevacizumab-800CW ex vivo. Subsequent NIRF imaging showed a more intense fluorescent signal in the culprit plaques ( n = 11) than in the non-culprit plaques ( n = 3). A plaque received from an asymptomatic patient showed pathologic features similar to the culprit plaques. Cross-correlation with VEGF-A immunohistochemistry showed co-localization of VEGF-A over-expression in 91% of the fluorescent culprit plaques, while no VEGF-A expression was found in the non-culprit plaques ( p < 0.0001). VEGF-A expression was co-localized with CD34, a marker for angiogenesis ( p < 0.001). Ex vivo near-infrared fluorescence (NIRF) imaging by incubation with bevacizumab-800CW shows promise for visualizing VEGF-A overexpression in culprit atherosclerotic plaques in vivo.