Bone Abstracts

see P248....

Abnormal tissue levels of certain trace elements such as Zinc (Zn) were reported in various types of cancer. Little is known about the role of Zn in osteosarcoma.Using confocal synchrotron radiation micro X-ray fluorescence analysis, we characterized the spatial distribution of Zn in high-grade (G3) sclerosing osteosarcoma of nine patients (4 f/5 m; 7 knee/1 humerus/1 femur) following chemotherapy and wide surgical resection. The study was done in accord...

Analysis of genome wide data such as transcriptomics can identify genes of potential interest to bone biology. These techniques are primarily hypothesis-generating. Determining the role of candidate factors in bone ultimately requires in vivo experiments. Gene expression analysis of mouse osteoclast differentiation identified G protein-coupled receptor 137B (GPR137b) as highly upregulated. GPR137b is an orphan seven-pass transmembrane receptor of unknown func...

miRNAs are epigenetic regulators of gene expression, increasingly recognised as prominent regulators of bone metabolism. Following our in vitro studies of miRNAs profiles in osteoblasts we extended the research to human bone samples. Our aim was to find and functionally validate miRNAs differentially expressed in osteoporotic and osteoarthrotic bone with potential for targeting genes relevant in bone metabolism.Trabecular bone tissue samples wer...

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 ...

Objectives: X-linked hypophosphatemia (XLH) is a rare genetic disorder of phosphate metabolism caused by mutations in the PHEX gene. This pilot study aims to apply novel imaging techniques to asses the musculoskeletal phenotype of XLH patients by bidirectional axial transmission (BDAT) ultrasound, magnetic resonance spectroscopy (MRS) and high resolution peripheral quantitative computed tomography (HR-pQCT).Methods: BDAT bone ultrasound of the radius and...

Background/aim: X-linked hypophosphatemia (XLH) is a rare disease characterized by low phosphate level. Scientific evidence points to link between hypophosphatemia and obesity in general population. The aim of our longitudinal observational study was to investigate the prevalence of obesity and associated factors in a large cohort of children with XLH.Patients/methods: We selected 172 XLH-children of 5–20 years (113 girls/59 boys). Anthropometric pa...

Neurofibromatosis type I (NF1) is a monogenetic disorder caused by mutations in the NF1 gene encoding for the Ras-GAP protein neurofibromin. Apart from benign tumour development NF1 is frequently associated with skeletal manifestations such as osteopenia or debilitating focal skeletal dysplasia. To assess a function of Nf1 in osteocytes we here apply a combinatorial approach of biophysical, histological and molecular techniques allowing differential analysis ...

Objectives: We sought to identify the disease-causing mutations in two unrelated girls with a clinical diagnosis of osteogenesis imperfecta type IV.Methods: Whole-exome sequencing and cellular studies in skin fibroblasts were conducted.Results: We identified two homozygous variants in SPARC (NM_003118.3; c.497G>A (p.Arg166His) in individual 1; c.787G>A (p.Glu263Lys) in individual 2). Secreted protein, acidic, cyste...

Aging is a complex process that results in the decline of physiologic functions due to accumulation of damage in cells and tissues. Mesenchymal stem cells (MSCs) counteract this decline but their regeneration capacity decreases with age. In particular osteogenic differentiation potential of MSCs has been shown to decrease with age thereby contributing to slowed down bone formation and osteoporosis. While much is known about cellular aging of MSCs, little is known about factors...