Bone Abstracts

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)...

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 ...

Dominant osteogenesis imperfecta (OI) is a bone disease mainly caused by collagen type I mutations and characterized by bone fragility and growth delay. Nowadays no definitive cure is available. A zebrafish OI model (Chihuahua) carrying an heterozygous G574D substitution in the α1 chain of collagen type I was generated by ENU mutagenesis and is available in our laboratory. Control (WT) and mutant (Chi+/−) fish growth was followed up from day 1 post fertilization to ...

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Here we identify the lipolytic enzyme hepatic lipase (HL, encoded by Lipc) as a novel cell-autonomous regulator of osteoblast function. In an unbiased genome-wide expression analysis, we find Lipc – which was formerly thought to be expressed almost exclusively by the liver – to be highly induced upon osteoblast differentiation, as verified by quantitative Taqman analyses of primary osteoblasts in vitro and of bone samples in vivo. ...

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Bone marrow is the main hematopoietic organ of adults. There, hematopoietic stem cells from which all hematopoietic lineages can be generated are preferentially homing. Importantly, bone provides niches for early B cell differentiation and survival of long-lived plasma cells that produced antibodies. Thus, that perturbing bone homeostasis might impact B cell function and antibody production is a highly relevant hypothesis for patients receiving antiresorptive drugs.<p clas...

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...

Inflammatory stimuli can lead to bone loss by mechanisms that are not well understood. We recently showed that skin inflammation induces bone loss in mice and humans. In psoriasis, one of the prototypic IL-17A-mediated inflammatory human skin diseases, low bone formation and bone loss correlates with increased serum IL-17A levels. Similarly, in two mouse models with chronic IL-17A-mediated skin inflammation, K14-IL17Aind and JunB&...