Abstract 201: A New Multimodal Contrast Agent for Molecular Imaging of Adhesion Molecules Expressed in Atherosclerosis

Abstract

Background: Inflammation is involved in many chronic diseases, one of which is atherosclerosis. Early detection of inflammation could improve clinical management. Most existing contrast agents on the market are non-specific and single-modal. Our aim was to apply an innovative new multimodal contrast agent, a polyvinyl alcohol based microbubble (MB), to target adhesion molecules expressed in atherosclerosis, opening a new scenario for biomedicine. Objective: To evaluate a contrast agent with different surface modifications and their adhesion to inflammatory in vitro models as a proof of concept, by imaging inflamed endothelium, that is involved in the pathogenesis of atherosclerosis. Methods: Microbubbles were antibody (Ab) or peptide conjugated to the adhesion molecule of interest. To evaluate attachment between MBs and an inflamed murine cell line, endothelial cells (EC), confocal laser scanning microscopy (CLSM) and flow cytometry (FACS) were used. To verify expression of cell adhesion molecules we used FACS and western blot. Stimulated and non-stimulated cells were incubated with MBs conjugated with active ligands, or a negative control. Results: In endothelial cells CLSM showed an increased uptake, or adherence, of peptide-conjugated microbubbles compared to non-stimulated control. MBs tagged with Abs against; ICAM-1, VCAM-1, E-Selectin, or with Cyclic Arginine-Glycine-Aspartate (cRGD) peptide showed stronger adherence to EC compared to non-targeted control. Microbubbles labeled with cRGD-peptide was shown to be the most prominent, indicating a specific interaction. Conclusions: Adhesion molecules expressed in atherosclerosis may be targeted by our labeled multimodal contrast agent in vitro , with potential for disease specific diagnostics in vivo.