Bone Abstracts

Chondrosarcomas are cartilage-forming, poorly vascularized tumors. With an estimated annual incidence of 1 in 200 000, they represent the second malignant primary bone tumor of adults after osteosarcoma. These tumors are resistant to chemotherapy and radiotherapy, surgical excision remaining the only therapeutic option. However, very few cell lines and animal models are available, and the mechanisms behind their chemoresistance remain largely unknown. Our goal was to establish...

Fibroblast growth factor receptor 3 (FGFR3) is an important regulator of bone formation. Achondroplasia (ACH) is the most common form of dwarfism; it involved FGFR3 gene mutations, in which skull, appendicular and axial skeletons are affected. The comparative analyses of the skeletal phenotype of Fgfr3 mice (Fgfr3Y367C/+) and patients with ACH showed, in both cases, short stature, defective proliferation, and differentiat...

Biographical DetailsLaurence Legeai-Mallet is currently Director of Research at Imagine Institute-Paris Descartes University. She received her PhD in genetic from University of Paris V, she is a member of International skeletal dysplasia Society, European Skeletal Dysplasia Network and the French reference center of bone dysplasias. She has been involved in the field of skeletal disease s...

This study aims at determining if casein would lead to a better bone status than soy in the context of a moderate protein restriction (6% of total energy intake) in growing mice.Ten-week-old female Balb/C mice were divided in four groups of 15 animals. Two groups received 6% of their energy intake as protein, one as casein and the other as soy protein. The third group was a normal-protein control receiving 20% soy protein. The last group (positive contro...

Small GTPases of the Rho family (RhoA and Rac-1) are responsible for cytoskeleton dynamics (particularly actin polymerisation) and control cellular tension. For these reasons, they are implicated in the commitment of multipotent cells (MCs). In one hand, increased tension (important RhoA activity) is commonly associated with osteogenesis (OS), in the other hand, a reduced one (low RhoA activity) is associated with adipogenesis (AD). Nevertheless, precise RhoGTPases regulations...

The fibroblast growth factor receptor 3 (FGFR3) activation leads to dwarfism with a spectrum of severity, hypochondroplasia (HCH), severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN), and thanatophoric dysplasia (TD). Interestingly, FGFR3 mutations localized at the same position in the tyrosine kinase domain are responsible for HCH (p. Lys650Asn), SADDAN (p. Lys650Met) and TD (p. Lys650Glu).The mechanisms of FGFR3 activation ...

Background: Primary hyperparathyroidism (PH), whilst common in elderly populations, is much rarer in adolescents. Although up to 90% of cases are sporadic in nature, hereditary cases make up less than 10% of remaining causes. Multiple genetic causes and syndromes have been described in the literature including multiple endocrine neoplasia (MEN), familial hypocalciuric hypercalcemia and hyperparathyroidism-jaw tumour syndrome (HPT-JT).Presenting problem: ...

Bone sialoprotein regulates osteoblast activity and bone formation. In knockout (BSP−/−) mouse bone marrow (BM) stromal cell cultures, the pool of osteoprogenitor (OP) cells (CFU-F number) is not different from wild-type (+/+), nor is their early differentiation (same numbers of alkaline phosphatase positive colonies=CFU-ALP, although these are smaller), while the number of osteoblast, mineralized colonies (CFU-OB) is dramatically reduced. Because ossifi...

Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic cause of renal failure. Data from adult ADPKD population show increased fibroblast growth factor 23 (FGF23) levels while circulating Klotho levels decrease, with a low TmP/GFR even in patients with normal renal function. Moreover, in ADPKD animal models, cyst lining renal cells were demonstrated to produce FGF23, although the animals displayed FGF23 resistance. No data are available in a paediatr...

Background: High zoledronic acid (ZOL) dose protocol, one of the most potent inhibitors of bone resorption, is currently evaluated in a phase III clinical trial in Europe for the treatment of malignant pediatric primary bone tumors. The impact of such an intensive treatment on the craniofacial skeleton growth is a critical question in the context of patients with actively growing skeleton, in the light of our previous studies evidencing that endochondral bone formation was tra...