Open source software for semi-automated histomorphometry of bone resorption and formation parameters

Micro-CT analysis has become the standard method for assessing bone volume and architecture in small animals. However, micro-CT does not allow the assessment of bone turnover parameters such as bone formation rate and osteoclast (OC) number and surface. For these crucial variables histomorphometric analysis is still an essential technique. Histomorphometry however, is time consuming and, especially in mouse bones, OCs can be difficult to detect. The main purpose of this study was to develop and validate a relatively easy and rapid method to measure static and dynamic bone histomorphometry parameters. Here we present the adaptation of established staining protocols and three novel open source image analysis packages: TrapHisto, OsteoidHisto and CalceinHisto that allow rapid, semi-automated analysis of histomorphometric bone resorption, osteoid, and calcein double labelling parameters respectively. These three programs are based on ImageJ, but use a relatively simple user interface that hides the underlying complexity of the image analysis

Apc+/Min colonic epithelial cells express TNF receptors and ICAM-1 when they are co-cultured with large intestine intra-epithelial lymphocytes

48 ref.International audienc

Apc+/Min colonic epithelial cells express TNF receptors and ICAM-1 when they are co-cultured with large intestine intra-epithelial lymphocytes

48 ref.International audienc

Cannabinoid receptor type 1 protects against age-related bone loss by regulating osteoblast and adipocyte differentiation of bone marrow stromal cells

Osteoporosis is characterised by reduced bone formation with replacement of the bone marrow compartment by fat, due to an age-dependent reduction in osteoblast differentiation and a reciprocal increase in adipocyte differentiation. Here we report that the type 1 cannabinoid receptor (CB1) regulates this process to protect against age related bone loss. Mice with CB1 deficiency (CB1<sp>-/-</sp>) had a increased peak bone mass when compared with wild type littermates (females; 28% increase and males 14% increase) due to a reduction in bone resorption. However, CB1<sp>-/-</sp> mice developed an accelerated age-related osteoporosis characterised by reduced bone formation and a dramatic accumulation of fat in the bone marrow (BM) compartment. Studies <i>in vitro</i> showed that bone nodule formation was reduced by 45% in marrow stromal cells from CB1<sp>-/-</sp> mice when compared with wild type littermates (p<0.05) and expression of Runx2, alkaline phosphatase and osteopontin were reduced. Conversely, adipocyte differentiation was increased by 30% (p<0.02) in marrow stromal cultures from CB1<sp>-/-</sp> mice when compared with wild type. Adipocyte cultures from CB1<sp>-/-</sp> mice showed enhanced insulin-induced AKT activation and increased expression of the adipocyte-specific genes PPAR gamma and C/EBP when compared with wild type. Adipocyte differentiation was increased in wild type BM cultures exposed to the CB1 selective antagonist AM251, but these effects were blocked by the cannabinoid receptor agonist CP55,490 and the Gi/o inhibitor pertussis toxin, consistent with a CB1 mediated effect. Intracellular cAMP levels were elevated in stromal cells cultured from CB1<sp>-/-</sp> mice and these cells exhibited increased enhanced phosphorylation of the cAMP response element transcription factor CREB. The CB agonist CP55,490 inhibited cAMP accumulation in 3T3-L1 pre-adipocytes and this effect was reversed by AM251 and pertussis toxin. Furthermore, exposure of wild type stromal cells to AM251 was sufficient to stimulate adipogenesis in the absence of the phosphodiesterase inhibitor IBMX. Taken together, these observations indicate that CB1 regulates the commitment of mesenchymal stem cells to differentiate into osteoblasts and adipocytes by a cAMP mediated mechanism. The CB1 pathway therefore plays a unique role in bone metabolism by restraining peak bone mass through effects on osteoclast differentiation but by protecting against age-related bone loss by regulating adipocyte and osteoblast differentiation

Fabrication of a silver nanoparticle-coated collagen membrane with anti-bacterial and anti-inflammatory activities for guided bone regeneration

Alveolar bone loss is a common problem that affects dental implant placement. A barrier between the bone substitute and gingiva that can prevent fibro-tissue ingrowth, bacterial infection and induce bone formation is a key factor in improving the success of alveolar ridge reconstruction. This study aims to develop a bioactive collagen barrier material for guided bone regeneration, that is coupled with anti-bacterial and anti-inflammatory properties. We have evaluated two silver coating methods and found controllable and precise coating achieved by sonication compared with sputtering. The optimized AgNP-coated collagen membrane exhibited excellent anti-bacterial effects against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) with limited cellular toxicity. It also displayed effective anti-inflammatory effects by reducing the expression and release of inflammatory cytokines including IL-6 and TNF-alpha. Additionally, AgNP-coated collagen membranes were able to induce osteogenic differentiation of mesenchymal stem cells that guide bone regeneration. These findings demonstrate the potential application of AgNP-coated collagen membranes to prevent infection after bone graft introduction in alveolar ridge reconstruction