Integrin [alpha]^sub v^[beta]^sub 3^ as a PET Imaging Biomarker for Osteoclast Number in Mouse Models of Negative and Positive Osteoclast Regulation

The goal of this study was to determine the specificity of ^sup 64^Cu-CB-TE2A-c(RGDyK) (^sup 64^Cu-RGD) for osteoclast-related diseases, such as Paget's disease or rheumatoid arthritis. 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 ^sup 64^Cu-RGD, followed by determination of serum TRAP5b and bone histology. Standard uptake values were determined to quantify ^sup 64^Cu-RGD in bones and other tissues. Mice treated with OPG showed decreased bone uptake of ^sup 64^Cu-RGD at 1, 2, and 24 h post-injection of the tracer (p