Bone Abstracts

see P168....

Fibronectin is produced in different isoforms by osteoblasts during differentiation. In contrast to the circulating Isoform, which lacks extra domains, the fibronectin laid down by the osteoblasts in the matrix contains one or both extra-domains called EDA and EDB. We had found that deletion of fibronectin in osteoblasts decreased BMD. This is mediated by diminished osteoblast differentiation and cannot be corrected by the circulating isoform of fibronectin, suggesting a role ...

Cholestatic liver disease is often associated with increased fracture risk. We had found that circulating levels of a fibronectin isoform called oncofetal fibronectin (oFN) were elevated in patients with primary biliary cirrhosis. Indeed, injecting oFN to mice suppressed osteoblast differentiation and bone mineral density in vivo, suggesting it is responsible for bone loss in these patients. The aim of this study was to define the mechanism by which oFN affects osteob...

Background: Infantile Hypophosphatasia (HPP) is an inborn error of metabolism characterized by low serum alkaline phosphatase activity caused by loss-of-function mutations within the ALPL-gene encoding the tissue nonspecific isoenzyme of ALP (TNSALP). TNSALP controls skeletal and dental mineralization by hydrolyzing inorganic pyrophosphate, a potent inhibitor of bone mineralization. Patients develop substantial skeletal disease, failure to thrive, and sometimes vitamin B6&#150...

Introduction: Loss in bone mineral density may occur soon after initiation of adjuvant therapy for hormone-receptor-positive (HR+), breast cancer (BC) and correlates with changes in hormone levels. Adding zoledronic acid (ZOL) to adjuvant treatment for BC can preserve/improve bone mineral density and delay disease recurrence; however, effects of ZOL on endocrine hormone levels are currently unclear.Methods: Probone II assessed the course of endocrine hor...

Introduction: Bone mineral density (BMD) evaluations have shown that adjuvant chemotherapy or endocrine therapy (ET) for early breast cancer (BC) is associated with accelerated BMD loss and increased fracture risk. In recent studies, zoledronic acid (ZOL) increased BMD in premenopausal and postmenopausal women with BC, and improved disease-free survival in some patient subsets compared with no ZOL. The purpose of the current study was to investigate the effect of adjuvant trea...

Objective: Oosteoporoti fractures are a growing problem especially in aged societies of industrialized countries. Therefore, a clinical demand for synthetic bone graft substitutes is increasing. Despite the general success CPC showed clinically, development of CPC-based material by adding stronsium could improve its suitability to treat osteoporotic fractures.Methods: Sprague–Dawley rates model of induced osteoporosis via multi-deficiencies diet com...

Due to its huge socio-economic impact a better understating of osteoporotic fracture healing is crucial.Thirty-one female merino land sheep were randomly divided into four groups. (i) Untreated control-group (C, n=8); (ii) bilateral ovariectomy (OVX, n=7); (iii) OVX and calcium-deficient diet (OVXD, n=8); and (iv) OVXD and additional biweekly corticosteroid injections (OVXDS, n=8). Drill-hole defects (7.5 mm in diamete...

Osteoclasts are multinucleated giant cells derived from the monocyte/macrophage lineage in the presence of receptor activator of nuclear factor kappa-B ligand (RANKL) and colony-stimulating factor 1 (CSF1). The bone remodeling process in zebrafish is incompletely understood. Here we describe several methods to quantify bone formation and resorption using a zebrafish mutant that lacks functional colony stimulating factor 1a receptor (csf1ramh5/mh5). Mice deficient in...

Osteoclasts are myeloid-derived cells that degrade bone through the localized production of acid and proteases. The catabolic action of osteoclasts is counterbalanced by formation of new matrix by osteoblasts. In mammals, bone resorption and formation are coupled through crosstalk between osteoclasts and osteoblasts. Zebrafish are emerging as a valuable model to study bone biology, but how closely zebrafish osteoclast function parallels that of higher vertebrates is unknown. T...