Assessment of subchondral bone microdamage quantification using contrast-enhanced imaging techniques.

Bone microdamage is common at subchondral bone (SCB) sites subjected to repeated high rate and magnitude of loading in the limbs of athletic animals and humans. Microdamage can affect the biomechanical behaviour of bone under physiological loading conditions. To understand the effects of microdamage on the mechanical properties of SCB, it is important to be able to quantify it.

Reducing the prosthesis modulus by inclusion of an open space lattice improves osteogenic response in a sheep model of extraarticular defect.

Stress shielding is a common complication following endoprosthetic reconstruction surgery. The resulting periprosthetic osteopenia often manifests as catastrophic fractures and can significantly limit future treatment options. It has been long known that bone plates with lower elastic moduli are key to reducing the risk of stress shielding in orthopedics.

Effect of a protease-activated receptor-2 antagonist (GB88) on inflammation-related loss of alveolar bone in periodontal disease.

Background And Objective: Protease-activated receptor-2 (PAR ), a pro-inflammatory G-protein coupled receptor, has been associated with pathogenesis of periodontitis and the resulting bone loss caused by oral pathogens, including the keystone pathogen Porphyromonas gingivalis (P. gingivalis). We hypothesised that administration of a PAR antagonist, GB88, might prevent inflammation and subsequent alveolar bone resorption in a mouse model of periodontal disease.

Biomechanical and Microstructural Properties of Subchondral Bone From Three Metacarpophalangeal Joint Sites in Thoroughbred Racehorses.

Fatigue-induced subchondral bone (SCB) injury is common in racehorses. Understanding how subchondral microstructure and microdamage influence mechanical properties is important for developing injury prevention strategies. Mechanical properties of the disto-palmar third metacarpal condyle (MCIII) correlate poorly with microstructure, and it is unknown whether the properties of other sites within the metacarpophalangeal (fetlock) joint are similarly complex.

Microstructural properties of the proximal sesamoid bones of Thoroughbred racehorses in training.

Background: Proximal sesamoid bone fractures are common catastrophic injuries in racehorses. Understanding the response of proximal sesamoid bones to race training can inform fracture prevention strategies.

Objectives: To describe proximal sesamoid bone microstructure of racehorses and to investigate the associations between microstructure and racing histories.

Associations between the radiographic appearance of vascular channels in proximal sesamoid bones, their microstructural characteristics and past racing performance in Thoroughbreds.

Background: Abnormalities in vascular channel appearance within the proximal sesamoid bone (PSB) are the most common findings in Thoroughbred yearling presale radiographs and are often evaluated on radiographs of adult racehorses. Despite this, their pathogenesis and clinical significance are poorly understood, and associations with racing performance are inconsistent.

Objectives: To determine microstructural characteristics of the PSBs associated with the radiographic appearance of vascular channels using microcomputed tomography (µCT) and to determine associations with past racing performance in mature horses.

Keratinocyte-specific ablation of protease-activated receptor 2 prevents gingival inflammation and bone loss in a mouse model of periodontal disease.

Chronic periodontitis is characterised by gingival inflammation and alveolar bone loss. A major aetiological agent is Porphyromonas gingivalis, which secretes proteases that activate protease-activated receptor 2 (PAR ). PAR expressed on oral keratinocytes is activated by proteases released by P.

The vacuolar H ATPase V subunit d is associated with chondrocyte hypertrophy and supports chondrocyte differentiation.

Chondrocyte hypertrophy makes important contributions to bone development and growth. We have investigated a number of novel cartilage genes identified in a recent transcriptomic study to determine whether they are differentially expressed between different zones of equine foetal growth cartilage. Twelve genes (, , , , , , , , , , and ) were found to be more highly expressed in the zone of hypertrophic chondrocytes than in the reserve or proliferative zones, whereas and were expressed at lower levels in the hypertrophic zone than in the reserve zone.

A T cell-specific knockout reveals an important role for protease-activated receptor 2 in lymphocyte development.

Activation of protease-activated receptor-2 (PAR) expressed by T cells has been linked to the bone loss associated with periodontitis. We generated PAR conditional-null mice and crossed these with mice expressing Cre recombinase under control of the Lck proximal promoter, to produce T cell-specific PAR-null mice in order to further study the cellular mechanism involved in periodontitis. Here we report that efficient deletion of PAR in thymocytes isolated from T cell-specific PAR-null mice resulted in thymic and splenic hypoplasia and a reduction in the cells of the cortex and a loss of distinction between the cortex and the medulla of the thymus.

Identification of novel osteochondrosis--Associated genes.

During the early stages of articular osteochondrosis, cartilage is retained in subchondral bone, but the pathophysiology of this condition of growing humans and domestic animals is poorly understood. A subtractive hybridization study was undertaken to compare gene expression between the cartilage of early experimentally induced equine osteochondrosis lesions and control cartilage. Of the many putative differentially expressed genes identified, eight were confirmed by quantitative PCR analysis as differentially expressed, in addition to those already known to be associated with early lesions.