Bone Abstracts

Rheumatoid arthritis (RA) and osteoarthritis (OA), two common types of arthritis, affect the joints mainly by targeting the synovium and cartilage. Increasing evidence indicates that a significant network connects synovitis and cartilage destruction during the progression of arthritis. We recently demonstrated that hypoxia-inducible factor (HIF)-2α causes RA and OA by regulating the expression of catabolic factors in fibroblast-like synoviocytes (FLS) or chondrocytes. To ...

It is well known that thyroid hormone (TH) is essential for normal bone growth and development. However, the mechanisms by which TH regulates these processes are poorly understood. Recently, the sympathetic nervous system (SNS) was identified as a potent regulator of bone metabolism. In vivo studies by our group have shown that TH interacts with the SNS to regulate bone mass and structure, and that this interaction involves α2 adrenoceptor (α2-A...

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Objectives: This study is aimed at investigating of histological features of mandibular condylar cartilage (MCC) in rats after 2-month inhalation of epichlorohydrin (ECh) vapors and administration of thiotriazoline (Th) and Echinaceae tinctura (ET) as medication.Methods: The experiment involved 420 male rats (young, adult and senile). The animals were split into the groups: 1st group comprised control animals, the 2nd group comprised the animals...

In a recent unbiased transcriptomic study of genes associated with equine osteochondrosis, we identified several novel cartilage genes. The current study was undertaken to determine whether these genes are regulated during chondrocyte hypertrophy, and to identify novel hypertrophy-associated genes for further study in vitro. Gene expression was investigated by quantitative PCR (qPCR) in different zones of growth cartilage microdissected from equine foetal metatarsal b...

Hypoxia and the hypoxia-inducible factor 1alpha (Hif1alpha) are known to play critical physiological functions in endochondral bone development. However, their role in abnormal cartilage formation (chondrodysplasia) is unknown. Our goal was to test the possibility that altered oxygen homeostasis, which would result in abnormal Hif1alpha expression and activity, could lead to chondrodysplasia. This was done using matrix metalloproteinase (MMP) 9 and 13 deficient mice, which pre...

While the connection between under-nutrition and growth retardation is well documented, the opposite connection between over-nutrition and bone development was barely studied. For instance, obese children grow faster in height than normal-weighed children, and prospective studies demonstrated an over-presentation of obese children amongst fracture cases. Furthermore, little is known about the direct effect and the underlying cellular and molecular mechanisms of the diet or sin...

Desbuquois dysplasia (DBQD) is a rare recessive chondrodysplasia, characterized by growth retardation, multiple dislocations and advanced carpal ossification. Two forms of DBQD have been described on the basis of the presence (type 1) or absence (type 2) of characteristic hand anomalies. DBQD type 1 is caused by mutations in the Calcium-Activated Nucleotidase 1 gene (CANT1), while DBQD type 2 is caused by mutations in the xylosiltransferase 1 gene.CANT1 ...

Background: Estrogens act on estrogen receptors distributed in articular cartilages, synovial membrane, and ligaments, which are thought to be related with degenerative changes. Meanwhile, progesterone is known to have a weak anabolic action on bone formation. This study evaluates the effects of estrogen and progesterone hormone on bone/cartilage turnover in ovariectomized (OVX) rats.Methods: Thirty-five 7-month-old female Sprague–Dawley rats were r...

Reduced availability of oxygen, i.e. hypoxia, could occur during disuse, bone development, and fracture. Cartilage tissue is avascular in nature and the microenvironment of cartilage is hypoxic. Hypoxic regulation of gene expression generally involves activation of the hypoxia-inducible factor (HIF) transcription pathway. Receptor activator of nuclear factor-kappaB ligand (RANKL) is an osteoblast/stromal cell derived essential factor for osteoclastogenesis. Hypoxia-induced enh...

COMP (Cartilage Oligomeric Matrix Protein) is a member of the thrombospondin family of extracellular matrix proteins and also referred to as thrombospondin-5. Mutations in COMP lead to chondrodysplasias. Here we studied COMP in zebrafish (Danio rerio) which is a powerful vertebrate model organism. In silico analysis revealed that only one COMP coding gene exists in zebrafish and that the domain structure of COMP is fully conserved. Inspection of gene locus and phyloge...

Introduction: The matrilin-3 polymorphism T298M has been described to be associated with hand osteoarthritis in the carpometacarpal joint 1 (CMC1) and with spinal disc degeneration. In vitro studies revealed that expression levels, processing and secretion of matrilin-3 T298M were similar to the wt protein. Structural analysis indicated an impact on the formation of collagen II/IX/XI heterofibrils, whereas the binding to collagen was not affected. We have now generate...

Skeletogenesis is an intricate process controlled by numerous transcriptional factors, hormones and signalling pathways. Recently, microRNAs emerged as important players in skeletogenesis but, only few were identified and most of their targets remain unknown. Previous works showed that miR-199a-2/214 cluster is essential for skeletal development and that miR-214 inhibits bone formation in mammals. However, data regarding its skeletal role in other vertebrates is scarce and its...

Background, subjects and methods: Vitamin D insufficiency in older people in the UK is common and may cause secondary hyperparathyroidism and bone loss. In a randomised, double blind intervention trial to optimise “Vitamin D status in Older People’ (VDOP) three oral dosages of vitamin D3 (12 kIU, 24 kIU or 48 kIU/month) were given for 12 months to 375 participants aged over 70 years (ANOVA) adjustment for covariables with results below presented in ascendi...