Imaging Macrophage and Hematopoietic Progenitor Proliferation in Atherosclerosis

Rationale:Local plaque macrophage proliferation and monocyte production in hematopoietic organs promote progression of atherosclerosis. Therefore, noninvasive imaging of proliferation could serve as a biomarker and monitor therapeutic intervention. Objective:To explore 18F-FLT positron emission tomography–computed tomography imaging of cell proliferation in atherosclerosis. Methods and Results:18F-FLT positron emission tomography–computed tomography was performed in mice, rabbits, and humans with atherosclerosis. In apolipoprotein E knock out mice, increased 18F-FLT signal was observed in atherosclerotic lesions, spleen, and bone marrow (standardized uptake values wild-type versus apolipoprotein E knock out mice, 0.05±0.01 versus 0.17±0.01, P<0.05 in aorta; 0.13±0.01 versus 0.28±0.02, P<0.05 in bone marrow; 0.06±0.01 versus 0.22±0.01, P<0.05 in spleen), corroborated by ex vivo scintillation counting and autoradiography. Flow cytometry confirmed significantly higher proliferation of macrophages in aortic l...