Amanda M. Hamilton1,2, Andre JL Belisle1,2, Brian K. Rutt2,3, Ralph Weissleder4, Derek R. Boughner2,5, Kem A. Rogers1
1Anatomy & Cell Biology, University of Western Ontario, London, Ontario, Canada; 2Imaging, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada; 3Radiology, University of Western Ontario, London, Ontario, Canada; 4Massachusetts General Hospital, Boston, MA, USA; 5Medicine, University of Western Ontario, London, Ontario, Canada
Aortic valve sclerosis (AVS) is a prevalent vascular disease with macrophage invasion as a critical pathological feature. This study tested the efficacy of identifying AVS in cholesterol-fed rabbits using passive targeting of macrophages with iron oxide-enhanced MRI. In vivo and ex vivo imaging exhibited evidence of iron oxide uptake in both control and cholesterol-fed rabbit valves. Histopathological analysis revealed iron staining in myofibroblasts in both control and cholesterol-fed rabbit valves as well as in macrophages in cholesterol-fed rabbits only. Our findings suggest that passive targeting of macrophages is insufficient for early AVS identification and macrophage-targeted contrast agents should be investigated.