Bone Abstracts

Osteoporosis is a frequent disease leading to an increased risk of fractures caused by a systemic impairment of bone mass, strength, and microarchitecture. Given the emerging role of the Wnt signaling pathway in bone biology, we focused on the function of the important Wnt inhibitor dickkopf-1 (Dkk-1) and examined how the deletion of Dkk-1 solely in osteoblasts or osteocytes influences bone homeostasis. Therefore, we used the Cre-LoxP recombination system and crossed Dkk-1-flo...

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Milk fat globule-epidermal growth factor 8 (MFG-E8) is a glycoprotein that controls the engulfment of apoptotic cells and exerts anti-inflammatory effects. It has been implicated in the pathogenesis of several diseases, but its role in the bone microenvironment is still unknown. Here we tested the hypothesis that MFG-E8 also regulates bone metabolism and the development of arthritis.MFG-E8 expression was detected in mouse bones and primary murine osteobl...

Glucocorticoids (GC) are effective drugs in the treatment of inflammatory diseases, including various forms of arthritis. However, their use is limited by negative effects on bone mass and strength, resulting in increased osteoporotic fractures. Conditional knockout mice demonstrated that the GR in osteoblasts is essential for GC-dependent bone loss. Recent studies show that GC profoundly inhibit Wnt signaling by stimulating the expression of Wnt antagonists such as dickkopf-1...

Introduction: Bone metastases represent a frequent complication of breast cancer and are characterized by increased tumour-driven activation of osteoclasts and subsequent bone loss. Aminobisphosphonates inhibit osteoclast function and are established therapies of skeletal metastases. Similar to statins, they block the mevalonate pathway and are thought to have direct anti-tumour effects. Here, we report on the anti-tumour potential of a sequential inhibition of the mevalonate ...

Breast cancer is the most frequent malignancy in women and frequently results in osteolytic bone metastases. Amino-bisphosphonates are a standard bone protective therapy and, similarly to statins, inhibit the mevalonate pathway that is crucial for posttranslational protein modifications (farnesylation and geranylation). Direct anti-tumor effects of amino-bisphosphonates and statins have been suggested but high concentrations are necessary to achieve meaningful effects. Our stu...

Wnt proteins and their cognate receptors play a significant role in malignant diseases, in particular in prostate cancer (PCa). We previously showed that WNT5A inhibits PCa cell proliferation and induces apoptosis in vitro, leading to reduced PCa growth in vivo. However, the involved receptors remain unknown. Here, we determine the role of two Wnt receptors (FZD8, RYK) and their influence on the WNT5A-induced effects on PCa cells.The ex...

Antenatal glucocorticoid (GC) injections are not only used to enhance fetal lung maturation in preterm children but also for the treatment of maternal conditions such as autoimmune diseases or infections. Animal models and clinical studies suggest that the regulation of the hypothalamic–pituitary–adrenal axis is altered in the offspring of GC-treated mothers with increased sensitivity to stress.Objective: The aim of this study is i) to define t...

Fractures of the hip are serious complications associated with osteoporosis. In previous work we found evidence of osteoblast dysfunction in middle aged men with idiopathic osteoporosis. The aim of this study was to investigate gene expression and bone microarchitecture in bone samples derived from elderly men with osteoporotic hip fractures. Femoral heads and adjacent bone tissue from 12 men with low-trauma hip fractures (mean age 82±7 years) and consecutive surgical hip...

Chronic stress and depression are associated with alterations in the hypothalamic–pituitary–adrenal signalling cascade and considered a risk factor for bone loss and fractures. However, the mechanisms underlying the association between stress and poor bone health are unclear. Utilising a transgenic (tg) mouse model in which glucocorticoid signalling is selectively disrupted in mature osteoblasts and osteocytes (HSD2OB-tg mice), the current study examines t...