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Posts Tagged ‘P1NP’


Reporter: Aviral Vatsa PhD, MBBS

A new study in JBMR highlights a novel glucocorticoid receptor modulator Compound A (CpdA) with the potential for an improved risk/benefit profile. They tested the effects of CpdA on bone in a mouse model of GC‐induced bone loss.

This study underlines the bone‐sparing potential of CpdA and suggests that by preventing increases in the RANKL/OPG ratio or DKK‐1 in osteoblast lineage cells, GC‐induced bone loss may be ameliorated. © 2012 American Society for Bone and Mineral Research.

RESULTS

PRED reduced the total and trabecular bone density in the femur by 9% and 24% and in the spine by 11% and 20%, respectively, whereas CpdA did not influence these parameters. Histomorphometry confirmed these results and further showed that the mineral apposition rate was decreased by PRED whereas the number of osteoclasts was increased. Decreased bone formation was paralleled by a decline in serum P1NP, reduced skeletal expression of osteoblast markers, and increased serum levels of the osteoblast inhibitor dickkopf‐1 (DKK‐1). In addition, serum CTX‐1 and the skeletal RANKL/OPG ratio were increased by PRED. None of these effects were observed with CpdA. Consistent with the in vivo data, CpdA did not increase the RANKL/OPG ratio in MLO‐Y4 cells. Finally, CpdA also failed to transactivate DKK‐1 expression in bone tissue, BMSCs and osteocytes.

METHODS

Bone loss was induced in FVB/N mice by implanting slow‐release pellets containing either vehicle, prednisolone (PRED) (3.5 mg), or CpdA (3.5 mg). After 4 weeks, mice were killed to examine the effects on the skeleton using quantitative computed tomography, bone histomorphometry, serum markers of bone turnover, and gene expression analysis. To assess the underlying mechanisms, in vitro studies were performed with human bone marrow stromal cells (BMSCs) and murine osteocyte‐like cells (MLO‐Y4 cells).

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