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DOI: 10.1055/s-0032-1329747
Quantitative differences in binding of a fluorescent bisphosphonate to bone minerals are observed in mouse models of bone turnover: potential for application as an imaging probe for bone metabolism
Aim: To establish an in-vivo assay which could quantitatively detect changes in bone metabolism. Such an imaging tool would also be useful in monitoring efficacy of new therapies in bone metastases.
Material und Methods: Osteosense750 (Perkin Elmer), a fluorescent bisphosphonate, was injected into overectomized (OVX) mice (bone loss) and following parathyroid hormone (PTH) treatment (bone gain). The fluorescent signal at the knee region of the hind legs and the spine was collected using an optical imaging device (FMT2500LX, Perkin Elmer). Parallel micro-CT scans (vivaCT40, Scanco Medical) were performed to confirm the efficacy of our models.
Results: OVX mice showed significantly reduced binding of Osteosense750 compared to control mice. Treatment with PTH failed to show any significant increase in bone fluorescence compared to control mice. New bone formation was further investigated by measuring the binding kinetics of Osteosense750. There was significantly increased binding kinetics in PTH-treated mice. These findings are consistent with the changes observed in bone density by micro-ct analysis.
Discussion: Our results suggest that measurement of kinetics of Osteosense750 binding can provide a quantifiable assay system to monitor bone growth at specific skeletal sites in vivo.
Conclusion: The assay will now be tested in osteolytic and osteoblastic bone metastatic mouse models.
Optical Imaging - bone metabolism - bisphosphonate