Bone Abstracts

Background and methods: Pigment epithelium-derived factor (PEDF) is a potent antiangiogenic factor, ubiquitously expressed and secreted in human tissues. Hypertrophic cartilage and osteoblasts express PEDF that binds to type I collagen and glycosaminoglycans in the extracellular matrix. Two rare forms of osteogenesis imperfecta (OI) with intact collagen synthesis are associated with PEDF deficiency. Histological observations revealed excessive osteoid formation and prolonged m...

Mineralized tissues like bone, articular calcified cartilage or mineralized turkey leg tendon (MTLT) are build by a composite of hydroxyapatite nano-particles and organic matrix. In bone and MTLT the matrix is formed by collagen type-I, but in contrast to bone in MTLT the collagen is uniaxial orientated, while in cartilage the matrix consists of collagen type-II and proteoglycans.Composition/orientation differences were investigated by a new scanning aco...

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The local mechanical properties of bone are influenced not only by the material chemical composition but also by the spatial arrangement of the component’s e.g. orientation of collagen matrix. However, not much is known about local elastic modulus variations in cortical bone. Our goal was to use acoustic imaging to map elastic properties of murine bone with a several microns resolution. Rodent long bones exhibit a permanent growth with endosteal/periosteal bone formation ...

Menopause is accompanied by a decrease in bone mineral density which can be caused by a reduction in bone volume and/or degree of bone matrix mineralization. Both of them are suggested to contribute to the increased fracture risk in postmenopausal individuals. In the present work, we aimed for information whether a drop in bone matrix mineralization is occurring in the perimenopausal stage of women. For this purpose, we measured the bone mineralization density distribution (BM...

Children with osteogenesis imperfecta (OI) still suffer from frequent fractures, despite bisphosphonate treatment. Thus new therapeutic approaches are needed. Sclerostin is a protein that is thought to inhibit bone formation. Treatment with sclerostin antibodies (SclAB) increases bone mass in animal models and in clinical trials and may be a rational therapy for OI as well.Transgenic (TgOI) Col1a1Jrt/+ mice were gene...

Background: Crohn’s disease (CD) is an inflammatory bowel disease which affects many organ systems including the skeleton. In children with CD, bone mineral density is frequently low. Bone metabolic abnormalities, including lower biochemical measures of bone turnover (NTX) as well as decreased bone formation indices at the tissue level have been reported. The aim of our study was to gain information on the bone matrix mineralization in CD.Methods: W...

For a reliable assessment of bone’s material quality in a clinical environment, a fast way to measure the mechanical properties of bone is needed. The investigation of material heterogeneity and anisotropy resulting from bone remodeling and mineralization requires an imaging technique with micrometer resolution. Scanning acoustic microscopy (SAM) using high-frequency lenses allows measuring the stiffness of bone under wet conditions in a non-destructive way with this spat...

Impaired bone material properties have been invoked as being responsible for the development of atypical femoral fractures (AFF) after long term bisphosphonate use. We therefore analyzed bone material properties in a bone biopsy obtained at the fracture site from an 88-year-old female with AFF, who had been treated with alendronate for 8 years. We used conventional histology, quantitative backscattered electron imaging (qBEI), and Raman spectroscopy (RS).<p class="abstext"...

Lack of Klotho, the co-receptor for the bone-derived hormone fibroblast growth factor-23 (FGF23), leads to a severe impairment in bone mineralization in mice. However, the mechanisms underlying the Klotho deficiency-associated defects in bone mineralization are still poorly understood. Here, we sought to elucidate the vitamin D independent role of Klotho in bone mineralization. To ablate increased vitamin D signaling in Klotho knockout mice (Kl−/−), we c...