Integrin αvβ3 as a PET Imaging Biomarker for Osteoclast Number in Mouse Models of Negative and Positive Osteoclast Regulation

Purpose The goal of this study was to determine the specificity of 64 Cu-CB-TE2A-c(RGDyK) ( 64 Cu-RGD) for osteoclast-related diseases, such as Paget's disease or rheumatoid arthritis. Procedures C57BL/6 mice were treated systemically with osteoprotegerin (OPG) for 15 days or RANKL for 11 days to suppress and stimulate osteoclastogenesis, respectively. The mice were then imaged by positron emission tomography/computed tomography using 64 Cu-RGD, followed by determination of serum TRAP5b and bone histology. Standard uptake values were determined to quantify 64 Cu-RGD in bones and other tissues. Results Mice treated with OPG showed decreased bone uptake of 64 Cu-RGD at 1, 2, and 24 h post-injection of the tracer ( p