Bone Abstracts

see P168....

Fibronectin is produced in different isoforms by osteoblasts during differentiation. In contrast to the circulating Isoform, which lacks extra domains, the fibronectin laid down by the osteoblasts in the matrix contains one or both extra-domains called EDA and EDB. We had found that deletion of fibronectin in osteoblasts decreased BMD. This is mediated by diminished osteoblast differentiation and cannot be corrected by the circulating isoform of fibronectin, suggesting a role ...

Osteoblasts line the inner surface of the bone and are located in close proximity to the bone marrow, where hematopoiesis takes place. Osteoblasts produce several cytokines that affect various steps of hematopoiesis, and produce fibronectin isoforms that affect cell differentiation. Little is known however on whether osteoblasts modulate the immune response. Our aim was to evaluate the role of fibronectin originating from the osteoblasts on hematopoiesis and the immune respons...

Cholestatic liver disease is often associated with increased fracture risk. We had found that circulating levels of a fibronectin isoform called oncofetal fibronectin (oFN) were elevated in patients with primary biliary cirrhosis. Indeed, injecting oFN to mice suppressed osteoblast differentiation and bone mineral density in vivo, suggesting it is responsible for bone loss in these patients. The aim of this study was to define the mechanism by which oFN affects osteob...