Bone Abstracts

see PP254....

Purpose: Multipotent stromal cells (MSC) have been considered promising for the regenerative strategies of articular cartilage. However, the MSC chondrogenic differentiation can ultimately lead to the formation of hypertrophic chondrocytes responsible for the calcification of cartilage. To prevent this MSC-dependent production of a calcified matrix in articular site, MSC hypertrophic differentiation has to be carefully controlled. Given that articular cartilage is avascular, w...

Purpose: Multipotent stromal cells (MSC)-based regenerative strategy is promising for the repair of cartilage, which is an avascular tissue in which cells experience hypoxia. Hypoxia is known to promote the early chondrogenic differentiation of MSC. Therefore, the aim of our study was to determine whether low oxygen tension could be used to enhance the regenerative potential of MSC for cartilage repair.Methods: MSC from rabbits or human adipose tissues (...

Mutations in the PHEX gene cause X-linked familial hypophosphatemic rickets (XLH) with severe bone (osteomalacia) and tooth abnormalities being the distinguishing features of this disease. The PHEX mutations lead to an increase in ASARM peptides (acidic serine- and aspartate-rich motif) and osteopontin fragments which inhibit bone extracellular matrix mineralization. MEPE-derived ASARM has been shown to accumulate in tooth dentin of patients with XLH where it may impair dentin...

Osteosarcoma is the most common primary malignant bone tumor, characterized by osteoid production and/or osteolytic lesions of bone. Despite recent improvements in chemotherapy and surgery, the problem of non-response to chemotherapy remains and constitutes a poor prognosis parameter. Consequently new therapeutic strategies aim to improve the overall rate of survival. The present work investigated the therapeutic interest of a dual phosphatidylinositol-3-kinase (PI3K)/mammalia...

Familial expansile osteolysis (FEO) is characterised by focal areas of increased bone turnover driven by bone-resorbing osteoclasts. The syndrome is caused by a heterozygous tandem insertion duplication mutation within the signal peptide region of TNFRSF11a (encoding receptor activator of NFκB; RANK). Our recent research has demonstrated that heterotrimeric receptor formation may hold the key to the disease phenotype. We have shown previously that, whilst homozygous overe...

Early-onset Paget’s disease of bone (ePDB), familial expansile osteolysis (FEO) and expansile skeletal hyperphosphatasia (ESH) are related syndromes caused by heterozygous tandem insertion duplication mutations within the signal peptide region of TNFRSF11a (encoding receptor activator of NFκB; RANK). Given that patients are always heterozygous for these mutations we have generated thirteen cell lines to investigate the molecular consequences of these mutations in...

Objectives: To evaluate the clinical outcomes of intravenous bisphosphonate treatment in children with mild-moderate osteogenesis imperfecta (OI) who had progressed from active bisphosphonate treatment to maintenance therapy for >2 years.Methods: A retrospective review was conducted on 17 patients with mild-moderate OI. Clinical data, fracture history, biochemistry, dual energy X-ray absorptiometry (DXA) parameters, vertebral measurements, bone age a...

Human mesenchymal stromal cells (hMSC) have been investigated as a clinical therapy to promote tissue repair. However, the disappearance of grafted cells soon after engraftment suggests that hMSC could principally act as initiators of repair through paracrine mechanisms.The aim of this study was to evaluate the relative contribution of grafted hMSC and host cells in promoting bone tissue repair. We isolated hMSC from three bone marrow (BM) donors, then d...

The interaction of Receptor Activator of NFkB ligand (RANKL) with its cognate receptor RANK is crucial for osteoclast formation. We studied eight point mutations within human RANK associated with rare forms of osteopetrosis to gain mechanistic insights into the regulation of RANK signalling.We investigated the role of the oligomerisation domain within the cytoplasmic region of RANK studying two mutations (W434X and G280X) identified in rare cases of oste...