Bone Abstracts

Background: Marfan syndrome (MFS) is a rare connective tissue disorder caused by mutation in the gene encoding the extracellular matrix protein fibrillin-1 (FBN1), leading to transforming growth factor-beta (TGF-β) signaling dysregulation. Although decreased axial and peripheral bone mineral density (BMD) has been reported in adults with MFS, data about the evolution of bone mass during childhood and adolescence are limited.Objectives: The aim of th...

Cancer cell growth is dependent on the microenvironmental support. Prostate and mammary cancer (PCa and MCa) cells preferentially metastasize to bone, where they induce either an osteoblastic or osteolytic response. These opposite stromal responses suggest that different types of cancers adopt distinct strategies to hijack the bone marrow/bone stroma for their growth support. However, the molecular cues underlying these divergent responses are largely elusive.<p class="abs...

Background: Pseudohypoparathyroidism (PHP) is a group of heterogeneous endocrine disorders characterised by hormone resistance, primarily to parathyroid hormone (PTH). The resistance is caused by defects in the GNAS gene, which encodes the Gsα protein that activates the cAMP pathway. PHP patients demonstrate elevated plasma PTH, hypocalcaemia, hyperphosphataemia with normal renal function. PTH resistance can be confirmed by Ellsworth-Howard test (PTH s...

IGF1 is an osteo-anabolic factor that stimulates osteogenic precursor cell differentiation. IGF1 is produced in bone in response to mechanical stimulation, but also in mechanically-stimulated muscle cells. IGF1 enhances the rate of mRNA translation in muscle cells via activation of the PI3K/AKT/mTOR pathway, thereby increasing in muscle mass. Therefore we hypothesized that IGF1 not just enhances osteogenic differentiation of precursors, but also stimulates protein syn...

Fibrous dysplasia (FD) is a benign skeletal disease caused by activating mutations of Gsα. These mutations lead to formation of abnormal and mechanically unsound bone and fibrotic tissue. Clinical sequelae include deformity, fracture, and pain. Studies in bisphosphonates have shown improvement in bone pain and inconsistent effects on FD mineralization; however interpretation has been limited by a lack of controlled trials.Objecti...

Background: Low vitamin D concentrations among children and adolescents at northern latitudes are frequently observed. Also, inverse associations between 25-hydroxyvitamin D (25(OH)D) and PTH concentrations have been found in children of different ages. More studies on the link between vitamin D status and childhood bone health are needed.Objective: To evaluate the status of serum 25(OH)D in autumn and the association between 25(OH)D concentrations and b...

Parathyroid hormone (PTH) is used to stimulate bone formation in osteoporotic patients, however concerns have been raised about the quality of the matrix produced since lower levels of total matrix mineral have been reported in osteoporotic and fracture patients treated with PTH. High resolution synchrotron-based Fourier Transform Infrared Microscopy (sFTIRM) was used to determine mineral content in age-matched bone during anabolic PTH treatment, using the simplified lamellar ...

Sclerostin, encoded by the SOST gene, functions as an inhibitor of the Wnt pathway and thus it is an important regulator of bone homeostasis. The fact that osteoblasts, the only cells expressing SOST, lay buried deeply in the bone matrix, poses intrinsic difficulties to the study of the regulation of this gene. Since RUNX2 and SP7/OSX are two known regulators of the differentiation of cells of the osteoblastic lineage, the aim of this study was to determine t...

Background: Hyperphosphatemic familial tumoral calcinosis (HFTC)/hyperostosis-hyperphosphatemia syndrome (HHS) is an autosomal recessive disorder due to deficiency of or resistance to intact fibroblast growth factor 23 (FGF23). This leads to hyperphosphatemia, increased renal reabsorption of phosphorus (TRP), and elevated or inappropriately normal 1,25-dihydroxyvitamin D (1,25D). Affected individuals may develop ectopic calcifications and/or diaphyseal hyperostosis. Mutations ...

see PP357....