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...

Osteoclasts resorb bone matrix through a specific adhesion structure called the sealing zone or actin ring, which is based on a belt of podosome. Much remains to be uncovered regarding the molecular mechanisms driving podosome organization into superstructures in particular the osteoclast podosome belt. Proteomic analyses in osteoclasts revealed the adaptor protein tensin 3 as a partner of Dock5, a Rac exchange factor necessary for podosome belt formation and bone resorption. ...

Many of our assumptions concerning oral implant osseointegration are extrapolated from experimental models studying skeletal tissue repair in long bones rather than in oral bones. This discrepancy between clinical practice and experimental research hampers our understanding on how alveolar bone forms or resorbs around implants and how osseointegration of oral implants can be improved. To overcome this disconnect, we have developed a mouse model which mimics oral implant placem...

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Hypoxia and the hypoxia-inducible factor 1alpha (Hif1alpha) are known to play critical physiological functions in endochondral bone development. However, their role in abnormal cartilage formation (chondrodysplasia) is unknown. Our goal was to test the possibility that altered oxygen homeostasis, which would result in abnormal Hif1alpha expression and activity, could lead to chondrodysplasia. This was done using matrix metalloproteinase (MMP) 9 and 13 deficient mice, which pre...

Fanconi anemia (FA) is a rare genetic disease associated with a progressive decline in hematopoietic stem cells leading to bone marrow failure. FA is also characterized by various developmental defects including short stature and skeletal malformations of the upper and lower limbs. Indeed, more than half of children affected with FA have radial-ray abnormalities with a tendency to early osteoporosis and osteopenia. However, the underlying mechanisms leading to bone defects in ...