Comparison of contrast agents for atherosclerosis imaging using cultured macrophages: FDG versus ultrasmall superparamagnetic iron oxide

Various noninvasive imaging methods have been developed to evaluate atherosclerotic plaques. Among them, 18F-FDG PET and MR imaging with ultrasmall superparamagnetic iron oxide particles (USPIO) have been used to quantify plaque inflamma-tion. Both methods are based on the efficient uptake of FDG and USPIO by macrophages in atherosclerotic lesions. Differently po-larized macrophages have been reported to have different characteristics that are involved in the pathologic development of atherosclerosis. M1 polarized macrophages are considered the more proatherogenic phenotype than M2 polarized mac-rophages. However, little is known regarding the association between macrophage polarization and FDG or USPIO ac-cumulation. In this study, we investigated intracellular FDG and USPIO accumulation in M1 and M2 polarized macrophages. Methods: THP-1 macrophages were differentiated into M1 an