Bone Abstracts

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 ...

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...

Cysteine-rich with EGF like domains 2 (Creld2) has recently been identified as an endoplasmic reticulum (ER) stress inducible gene in the context of skeletal dysplasia caused by mutant protein accumulating in the ER eliciting an unfolded protein response (UPR). Creld2 was originally implicated in ER stress following the treatment of Neuro2α cells with thapsigargin. Furthermore, the promoter of Creld2 contains an ER stress activating transcription factor ...

New food strategies should be developed to fight against child malnutrition and growth retardation in developing countries. Spirulina alga, one of the richest sources of vegetable protein, contains all essential amino acids. It easily grows in tropical regions. We hypothesized that impaired peak bone mass acquisition (PBMA) caused by dietary protein deficiency could be prevented by Spirulina supplementation in growing rats.One-month old female rats were ...

In adults, majority of bone marrow (BM) space of long bones is filled with fat tissue. Adipocytes are also present within trabecular bone areas such as vertebral bodies. Despite its prevalence the roles of BM fat in energy and bone metabolism have been largely overlooked. To characterize bone marrow metabolic activity we measured regional glucose uptake in femoral and vertebral bone marrow during fasting and insulin stimulation in normal weight healthy subjects.<p class="a...

The bone organ integrates the activity of bone tissue, bone marrow, and blood vessels and the factors ensuring this coordination remain ill defined. Bone sialoprotein (BSP) is with osteopontin (OPN) a member of the small integrin binding ligand N-linked glycoprotein (SIBLING) family, involved in bone formation, hematopoiesis, and angiogenesis. In rodents, bone marrow ablation induces a rapid formation of medullary bone which peaks by ~8 days (d8) and is blunted in BSP...

Purpose: To determine the association between socio-economic status (SES) and risk of hip fracture.Methods: Retrospective cohort study. We used a population database which contains primary care and hospital inpatient records of over >5 million people. Anyone registered in this database in 2009–2012 and resident in an urban area was eligible. Main measures: a validated SES composite index (accounting for proportion of unemployed, insufficiently e...

Periosteum contains mesenchymal progenitors and is essential for fracture healing. Signaling mechanisms governing periosteal reaction to injury remain largely unidentified. We previously investigated how PI3 kinase signaling affects the skeletal system using CblYF/YF knock-in (YF) mice wherein PI3K signaling is perturbed by abolition of interaction between Cbl, an E3 ubiquitin-ligase/adaptor protein, and p85 subunit of PI3K. YF mice displayed increased bone volume u...

Objectives: Osteogenesis imperfecta (OI) displays a heterozygous phenotype even amongst similar genotypes. It has therefore been difficult to establish a mouse model which represents clinical OI in children. By engrafting human OI bone into mice we have developed a hybrid model enabling us to investigate the efficacy of new treatments for this phenotypically diverse condition.Methods: Bone chips, that would otherwise be discarded, were collected from chi...

Objectives: Fibroblast growth factor 23 (FGF23) is a bone-derived phosphaturic hormone. The main target organ is the kidney, where FGF23 suppresses renal phosphate reabsorption and vitamin D synthesis. It also stimulates calcium reabsorption in the kidney. FGF23 secretion is stimulated by 1,25(OH)2D and by increased extracellular phosphate concentration, thus forming a feedback loop between kidney and bone. The bioactive intact FGF23 contains 251 amino acids and is glycosylate...