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Figure 3 Noninvasive Imaging of Apoptosis in Experimentally Induced Atherosclerosis With Radiolabeled Annexin A5

The images were obtained in both control (nonatherosclerotic) and atherosclerotic (athero) rabbits with or without caspase (Casp) inhibitor therapy. The top panel demonstrates planar gamma images, and the bottom panel presents micro-single photon emission computed tomography (CT) images superimposed on a morphologic background of micro-CT images. (A) Lack of annexin uptake in the region of the abdominal aorta as denoted by arrows in the normal rabbit with no atherosclerotic lesions. The annexin metabolism and excretion results in variation burden to liver (L), spleen (S), and kidney (K). (B) Compared with the negative control, significant radiotracer accumulation can be seen in the abdominal aorta (shown by arrows in front of vertebral column activity) of the animal with experimental atherosclerotic lesions. The animals receiving (C) nonselective caspase inhibitor or (D) selective caspase-1 inhibitor demonstrate total abrogation of annexin uptake. (E and F) The bottom panel reveals superimposed nuclear and CT images after treatment with selective caspase-3 inhibitor and caspase-8 inhibitor. The images are present in the set of 2 projections, transverse and sagittal. Whereas the caspase-3 inhibitor completely prevented annexin A5 uptake (arrows pointing to aortic area in front of vertebral uptake), caspase-8 inhibition did not affect annexin uptake or apoptosis. In caspase-8 inhibitor-treated animals, vivid uptake of radiotracer is seen in the abdominal aorta.