Bone Abstracts

see PP137....

Despite recent improvements in therapeutic management of osteosarcoma, ongoing challenges in improving the response to chemotherapy warrants new strategies still needed to improve overall patient survival. Among new therapeutic approaches, zoledronic acid represents a promising adjuvant molecule to chemotherapy to limit the osteolytic component of bone tumors. However, zoledronic acid triggers the elevation of heat shock proteins (Hsp), including Hsp27 and clusterin (CLU), whi...

It has been established that disturbances of intracellular signaling pathways strongly contribute to the oncologic process. Indeed, phosphatidylinositol-3-kinase (PI3K) became a key target in cancer therapy, due to its high frequency of mutation and/or gain of function of its catalytic subunits in cancer cells. In this context, we investigated the in vitro and in vivo effects of a new PI3Kα inhibitor, BYL719 (Novartis Pharma), on bone cells and its thera...

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...

Bone resorption and formation occur in a tightly regulated fashion reflecting the coupled activities of osteoclasts and osteoblasts. Several pathological conditions perturb this balance, including osteoporosis and skeletal metastases. In the case of metastases, the uncoupling of resorption and formation activities contributes to disseminated tumor cells homing to the bone and to tumor growth within the bone in highly localized regions. Therefore, a site-specific marker of bone...