The serotonin story is also interesting from the perspective that Lrp5 expression in the gut rather than the osteoblast has been proposed to be the critical site for Lrp5-mediated bone mass regulation.
Rajakumar SA, Papp E, Grandal I, Merico D, Liu CC, Allo B, et al. RANK-RANKL mediated bone destruction in B-cell acute lymphoblastic leukemia.
The balance between osetoclast mediated bone resorption and osteoblast mediated bone deposition is the essential feature of homeostatic bone remodelling.
The reduced bone turnover suggests that both treatments have effects on inflammatory mediated bone loss.
These monocyte-derived osteoclasts then mediate bone destruction.
This process is precisely coordinated to maintain the bone mass homeostasis mediated by multiple signaling pathways such as parathyroid hormone, transforming growth factor-β (TGF-β) and BMP [3], [7].
The association between menstrual irregularity and bone mass was partially mediated by markers of androgen status especially free testosterone.
Adult mice lacking JunB in the epidermis developed skin ulcerations in the facial area, hypergranulopoiesis and lost bone mass, most probably mediated by granulocyte colony-stimulating factor release from the epidermis (A Meixner, R Zenz, HB Schonthaler, L Kenner, H Scheuch, JM Penninger, EF Wagner, manuscript under revision).
We found that irregular cycles were associated with higher bone mass and this was partially mediated by SHBG and FAI.
Our own previous work revealed a significant increase of early vascularization mediated by EPC [ 7] which foster the bone mass increase supported by MSC in critical size defects of the femur [ 8, 9] and of the skull [ 10] in rats.
The Wnt pathway has also been implicated in mediating positive and negative control of bone formation and bone mass by environmental factors such as pharmacological glucocorticoids [31] [34] and mechanical stimulation [35].
