Bone Abstracts

Osteocytes make up >90% of bone cells, are embedded in mineralised matrix where they form a communication network. Osteocytes differentiate from osteoblasts, and are mechano-sensitive. They are very difficult to isolate with a dependence on cell lines for in vitro studies of osteocyte biology. Therefore new methods to study these cells are essential. Recent publications indicate that osteoblasts maintained in in vitro 3D collagen gels may differentiate to...

Introduction: Normal mechanical loading potently induces bone formation via effects on osteocytes. Current investigations of mechanical loading of bone do not reflect the interactions of the cells within it, mostly focusing on mechanical loading of osteoblasts in monolayers. Existing 3D models do not elucidate the osteoblast-osteocyte interactions that regulate mechanically-induced bone formation. We developed a novel in vitro 3D co-culture model of bone1 t...

Osteocytes differentiate from osteoblasts, are embedded in mineralised matrix and are critical regulators of bone remodelling. In vitro osteocyte models are limited to cell lines in monolayer, which do not represent their 3D environment in vivo. We have shown that osteoblasts in 3D gels differentiate along the osteocytic pathway. Since IGF1 regulates osteoblasts, and is involved in osteocyte response to mechanical loading, we hypothesised that IGF1 modulates ...

After trauma or carious lesion dental pulp healing is difficult to predict. In addition systemic diseases like diabetes mellitus can impair the regenerative capacity. New regenerative strategies target prolyl hydroxylase (PHD) by pharmacological inhibitors to stimulate hard and soft tissue healing. PHD inhibitors such as L-mimosine (L-MIM) induce vascular endothelial growth factor (VEGF) production by promoting angiogenesis. However, it is unclear if L-MIM is a feasible tool t...

We have reported femoral osteopenia in short term-vitamin D restricted rats without deterioration in tibial cortical bone volume (CBV), geometry or strength1. This study aimed to establish the effect of extended vitamin D deficiency in aged rat tibial volume and strength. Female Sprague-Dawley rats (9 m, n=6/group) were fed a diet containing varying vitamin D3 (D) levels (0, 2, 12, and 20 IU/day) with either low (0.1%, LCa) or high (1%, HCa) diet...

Osteoblasts have a high rate of energy consumption during bone formation and bone protein synthesis. Therefore, it is likely that decreased energy production that accompanies aging, could contribute to reduced osteoblast activity, a critical feature of senile osteoporosis, and that this reduction might be counteracted by favoring energy availability. Cells of the osteoblastic lineage generate 40–80% of the requested energy through fatty acid degradation, thus the modulati...

Background: It is well established that Asians have lower levels of vitamin D (25OHD) when compared to Caucasians. Vitamin D binding protein (DBP) levels are also lower in some races than in Caucasians.Objectives: i) To find out whether DBP is lower in Asians; ii) To find out whether free 25OHD is lower in Asians; iii) To find out whether PTH is increased in Asians and interpret this in relation to 25OHD levels and iv) To find out whether the increment i...

Low circulating levels of total 25-hydroxyvitamin D (25OHD) have been reported in obese people of different ethnicities in several countries. Low total 25OHD in obesity could be due to lower binding proteins (with normal free 25OHD), lower dietary intake or sunlight exposure, greater volume of distribution (pool size) or more rapid metabolic clearance.The aims of this study were to determine if free 25OHD and 1,25-dihydroxyvitamin D (1,25(OH)2...

Background: Hypercalcaemia is a risk following stem cell transplant (SCT) for all types of autosomal recessive osteopetrosis (ARO) due to restored osteoclast differentiation. This can be particularly severe in the osteoclast-poor (OP) form involving the tumour necrosis factor receptor superfamily 11A (TNFRSF11A) gene, encoding RANK. Denosumab, a monoclonal antibody blocking RANK activation, has been described for refractory post-SCT hypercalcaemia in two cases. Our case adds n...

Biographical DetailsDr Matthew L Warman is the Harriet M Peabody Professor of Orthopaedic Surgery and Genetics at Harvard Medical School. He attended college at Brown University and Medical School at Cornell University. While in medical school, he performed research with Dr Adele Boskey at The Hospital for Special Surgery. After medical school he trained in Pediatrics at the Children&#146...