Bone Abstracts

Osteoporosis is an age related disease characterised by a progressive decrease of bone mineral density and loss of bone quality. Twin studies show that genetic component contributes up to 85% of the BMD variability of population. Surprisingly little variability of BMD can be explained by genetic polymorphisms (~2.9%). This highlights the complex genetic architecture and suggests that many other molecular processes and genes have to be involved. Our previous research showed tha...

Introduction: Mortality after hip fracture is increased. However, only a few studies have explored for predictors beyond gender and age. Thus our aim was to study risk factors associated with increased mortality in hip fracture patients.Methods: Hip fracture patients (>50 years) admitted to a county hospital in 2004–2005 were consecutively invited for assessment at the hospital osteoporosis centre. A broad spectre of data was collected. Standard...

ASARM peptide (acidic, serine- and aspartate-rich motif) and osteopontin (OPN) fragments accumulate in X-linked hypophosphatemia patients and/or in the Hyp mouse model and, when phosphorylated, potently inhibit mineralization in osteoblast cultures. To investigate this inhibition, we modeled the binding to hydroxyapatite of the human OPN-ASARM peptide (DDSHQSDESHHSDESDEL) using RosettaSurface computational simulations. Peptide binding to hydroxyapatite atomic planes constructe...

Introduction: Prostaglandin E2 has bone-anabolic effects through EP4 receptor but its clinical utility is hindered by gastrointestinal side effects. To avoid these side effects, EP4 agonists (EP4a) were covalently linked to the bisphosphonate alendronate (ALN) to create two ALN-EP4a conjugate drugs, C1 and C2. When administered systemically, C1 and C2 will be target delivered to bone through ALN, where local hydrolytic enzymes liberate EP4a from ALN to exert bone an...

The biomineralization process is initiated inside matrix vesicles (MVs), with phosphate and calcium ions crystallizing as hydroxyapatite. This process is accomplished by the activities of several proteins, such as annexins (e.g. AnxV) that mediates Ca2+ influx into MVs and tissue-nonspecific alkaline phosphatase (TNAP), a phosphomonohydrolase that uses ATP and PPi as substrates. Dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylserine (DPPS...

Bone resorption and deposition occur in a tightly regulated fashion reflecting the coupled activities of osteoclasts and osteoblasts. Several pathological conditions perturb this balance between bone synthesis and resorption, including osteoporosis and skeletal metastases. The uncoupling of remodeling activities contributes to disseminated tumor cells homing to the bone and to tumor growth in bone. Therefore, a reliable marker of bone remodeling would be useful to provide a st...

The aim of the study is to compare the performance of FRAX vs TBS adjusted FRAX using Leslie B et al.1 method to better identify women at high fracture risk. The OsteoLaus cohort (1500 women 50–80 years living in Lausanne, CH) started in 2010. CRF for OP, FRAX, spine and hip BMD, VFA by DXA and TBS were recorded. Sensitivity and specificity in regard to vertebral fracture grade 2 and 3 has been calculated. Net reclassification improvement (NRI) had als...

Introduction: We describe a monozygotic twin pair, of which one boy was diagnosed with anorchia. Both were followed-up till age 17.Case report: At birth, in one twin 46 XY boy (A), testes were not palpable while his brother (B) was unaffected. Stimulation with human chorionic gonadotrophin (hCG) and orchidopexia were unsuccessful at age 3. A second hCG-stimulation test was performed at age 8, where serum testosterone response failed to increase. No testi...

Background: Although both testosterone and estrogens are considered essential for normal bone growth, epiphyseal maturation and bone mass accrual during adolescence, only very few data concerning the changes of estrogens, bone maturation, bone mineral density (BMD) and bone geometry in healthy boys at different pubertal stages have been published.Objectives: This study aimed to analyze the relationship between sex steroids and more especially estrogens a...

Proprotein convertase PC5/6 (Pcsk5) is expressed in mouse bone and Pcsk5 epiblast-specific conditional knockout mice have a bone phenotype displaying small size, delayed ossification and additional thoracic segments and ribs. Some features are attributed to growth and developmental factor 11 (GDF11) – a known substrate for PC5/6 – while the delayed mineralization has yet to be explained. Osteopontin (OPN) is a bone matrix protein with roles in miner...