Bone Abstracts

Introduction: Wnt/β-catenin signalling and mechanical loading are able to inhibit adipogenesis and to stimulate osteoblastogenesis of mesenchymal stem cells1,2. The involvement of β-catenin signalling in mechanically induced bone formation has already been shown in vivo using a tibia loading model3. The aim of this study was to investigate the influence of the activation of β-catenin on the osteogenic and adip...

Dysfunctions of Wnt/β-catenin and estrogen receptor signalling resulted in impaired mechanotransduction and bone loss as in osteoporosis. Previous studies demonstrated the interaction of these pathways in mechanotransduction in vitro and in vivo. In this study, the influence of the activation of estrogen receptor and β-catenin signalling on mechanically induced bone formation was investigated in ovariectomized mice. 12-week-old mice were ovariectomi...

Introduction: Fracture healing is impaired in aged and osteoporotic patients. Because bone formation is tightly regulated by the mechanical conditions in the fracture gap and because suitable mechanical stimuli improve fracture healing (Claes et al. 1998), we investigated whether low-magnitude high-frequency vibration (LMHFV; Rubin et al. 2004) is able to improve delayed fracture healing induced by age and ovariectomy in mice.Sudy desig...

One growth factor that potentially plays a role in fracture healing is midkine (Mdk). Mdk is expressed in chondrocytes during bone repair (Ohta et al. 1999) and has been shown to influence bone mass and mechanotransduction (Neunaber et al. 2010, Liedert et al. 2011). The aim of the present study was to evaluate the effects of Mdk-deficiency on bone repair in a standardized mouse femur osteotomy model.Mdk-deficient and wildtype ...

Mast cells (MCs) are pro-inflammatory sensor and effector cells of the immune system. MCs seem to play a role in bone metabolism, because patients with systemic mastocytosis develop osteoporosis. MCs are present in the fracture callus during bone healing, however, their function has not yet been investigated. Here, we examined the role of MCs in the inflammatory and repair phase during fracture healing.Male 12-week old MC deficient mice (Mcpt5-Cre R-DTA)...

Interleukin-6 (IL-6) plays an important role in bone metabolism and regulates fracture healing in a presently unknown process. In the fracture callus IL-6 expression is biphasic; it peaks during the inflammatory phase and again during intramembranous and endochondral ossification (Ai-Aql et al. 2008). Few studies using IL-6 knockout mice indicate that IL-6 might be crucial for bone healing (Yang et al. 2007). However, a generalized IL-6 knockout induces multi...

Chronic calcium- and vitamin-D-deficiencies are crucial risk factors for osteoporosis. However, their significance for fracture healing is still poorly investigated, despite the clinical evidence that osteoporotic bone healing is disturbed. This study addressed the important question, whether chronic deprivation of calcium and vitamin D compromises bone repair and if this could be rescued by a supplementation post-trauma. Because clinical hints suggest that a fracture induces ...

Previous studies demonstrated a negative influence of the growth- and differentiation factor midkine (MDK) on bone formation during bone remodeling and fracture healing. Additionally, MDK-deficiency protected mice from a loss of trabecular bone mass after ovariectomy (OVX). Therefore, we hypothesized that MDK may also be involved in the pathogenesis of delayed, osteoporotic fracture healing after OVX in mice. Thus, we analyzed the expression of MDK during bone regeneration and...

We recently established a large animal model of osteoporosis in sheep using hypothalamic–pituitary disconnection (HPD). As central regulation is important for bone metabolism, HPD-sheep developed severe osteoporosis because of low bone turnover. In this study we investigated metaphyseal fracture healing in HPD-sheep. To elucidate potential pathomechanisms, we included a treatment group receiving thyroxine (T4) and 17β-estradiol. Because clinically osteopor...