Bone Abstracts

Formation and growth of long bones occur through the process of endochondral ossification, which depends on proliferation and hypertrophy of chondrocytes in growth cartilage. In a subtractive hybridization study of equine cartilage, we recently identified a number of genes, the roles of which in growth cartilage have not been characterized. A subset of these genes was found to be differentially expressed between the zones of equine growth cartilage. The genes encoding ATPase H...

Calcium represents one of the most versatile and universal signalling particles regulating many different cellular processes. Changes in [Ca2+]i give rise to a vast diversity of modulatory events, amongst others, influencing activities of kinases and ion channels.It was demonstrated that nuclear magnetic resonance therapy (NMRT) treatment in osteoarthritis led to reduced pain and improved function followed by increase in quality of ...

Introduction: Using transgenic mice ectopically expressing Hoxa2 all along chondrogenesis, we previously associated the resulting animal phenotype to human idiopathic proportionate short stature. Our analysis showed that this overall size reduction was due to a negative influence of Hoxa2 in the very first step of endochondral ossification. As the molecular pathways underlying this pathogenesis are still unknown, we here tried to identify the impact of Hoxa2 overexpression on ...

Caffeine is a methylxanthine found in many foods and is widely consumed by the human population. Therefore, its effects and mechanisms in various tissues have been widely studied. But despite changing the postnatal bone growth, there are few studies about its effect on growth cartilage. The objective of this study was to evaluate the In vitro effects of caffeine on proliferation, apoptosis and gene transcripts expression of chondrogenic differentiation in growth carti...

Despite the presence of skeletal anomalies in fetuses of female rats treated with caffeine, their effect on bone’s formation and growth have not yet been elucidated. The objective of this study was to evaluate the effects of caffeine on the formation and endochondral bone growth in rats. There had been used 36 Wistar rats distributed among the control group and others treated with caffeine at doses of 25, 50, and 100 mg/kg. Treated groups received caffeine daily throughou...

The c-Myb transcription factor is associated with proliferation of undifferentiated cells in number of tissues, but recent data suggests its role also in differentiation. c-Myb is important in formation of the cartilage, bone and apparently also in hard tissue mineralization (Matalova et al. 2011).Embryonic micromasses were established from mouse front limbs at the embryonic day E12. Micromass cultures represent an effective tool for experimenta...

Objective: Chondrolysis, chondrocyte apoptosis, and local inflammation are described to exacerbate osteoarthritis development. We therefore aimed to investigate the effect of adrenomedullin (ADM) and its truncated peptide (22–52ADM) on in vitro and in vivo models. Both have exhibited anti-apoptotic and anti-inflammatory properties in collagen-induced arthritis (CIA) in mice.Methods: In normoxia or hypoxia (physiological condition),...

Purpose: Multipotent stromal cells (MSC) have been considered promising for the regenerative strategies of articular cartilage. However, the MSC chondrogenic differentiation can ultimately lead to the formation of hypertrophic chondrocytes responsible for the calcification of cartilage. To prevent this MSC-dependent production of a calcified matrix in articular site, MSC hypertrophic differentiation has to be carefully controlled. Given that articular cartilage is avascular, w...

Purpose: Multipotent stromal cells (MSC)-based regenerative strategy is promising for the repair of cartilage, which is an avascular tissue in which cells experience hypoxia. Hypoxia is known to promote the early chondrogenic differentiation of MSC. Therefore, the aim of our study was to determine whether low oxygen tension could be used to enhance the regenerative potential of MSC for cartilage repair.Methods: MSC from rabbits or human adipose tissues (...

Aim: Wnt/β-catenin pathway promotes cartilage breakdown in osteoarthritis. We have previously shown that sclerostin preserves chondrocyte maintenance in vitro by reducing chondrocyte catabolism through the inhibition of Wnt/β-catenin pathway. However, sclerostin restores partially the expression of the anabolic genes. We therefore investigated the effect of sclerostin in the activation of Wnt non canonical pathways mediated by Ca2+/CaMKII, JNK, an...

Background: Cartilage matrix breakdown in osteoarthritis (OA) is due to mechanical stress and inflammation leading to increased metalloproteinases (MMPs) production. Currently, IL1β is thought to have a major role in this process. IL1β is synthesized as an inactive precursor, which is cleaved into the secreted active form. This maturation process mainly occurs in the inflammasome complex. Inflammasome is constituted by initiators (including NALP3) and adaptor molecul...

Objectives: Sox9 is a dominant but insufficient transcription factor to induce thorough primary chondrogenesis, so other factors which may induce primary chondrogenesis besides Sox9 have been assumed. The previously reported function of transcription factor Nkx3.2 is to maintain chondrogenic phenotype by suppressing Runx2, while recent studies demonstrated that mouse Nkx3.2 null mice shows severe metaphyseal dysplasia which is similar to that seen in type II collagen a1 (Col2a...

Surgical removal of the stomach (gastrectomy, Gx) leads to osteopenia in animals and in humans. In the rat, Gx causes loss of calvaria and trabecular bone, which can be reduced by 2-oxoglutaric acid (2-Ox), a precursor of hydroxyproline the most abundant amino acid in bone collagen. The purpose of this study was to investigate the effects (if any) of Gx on articular cartilage and if dietary 2-Ox can protects against eventual adverse effects of Gx. Twenty female Sprague–Da...

Our earlier results indicate that prenatal exposure to dexamethasone, synthetic glucocorticoid, may disturb metabolic processes in skeletal system with long-term consequences. Functional foods show a beneficial action that improve the state of health and reduce the risk of disease. The study was performed to determine whether 2-oxoglutaric acid (2-Ox) can abolish the growth inhibiting effect of prenatally administered dexamethasone (DEX) manifested in the growth plate and arti...

Acrylamide is a byproduct that forms when certain carbohydrate and aminoacid rich foods are fried, baked, or roasted at high temperatures (>120°C). Our earlier study showed that acrylamide altered the morphology and histology of the small intestinal wall damaging the intestinal barrier and reducing absorption surface. The study was performed to determine whether acrylamide influences gut-bone axis in foetus when administered to guinea pig during the last 35 days of pr...

Background: Bone metabolic disorders, such as osteoarthritis (OA), osteopenia and osteoporosis have been associated to iron overload, both in humans and animal models. In the case of hereditary hemochromatosis (HH), arthropathy represents one of the most prevalent and disabling symptoms. This work aims at investigating the roles of HH-related HFE mutation and iron accumulation on chondrocyte metabolism.Materials and methods: Primary cultures of articular...

Indoxyl sulfate (IS) is one of a number of protein-bound uremic toxins that accumulate in patients with chronic kidney disease. Current conventional hemodialysis is ineffective at removing this toxin. Although IS may impair osteoblast function and induce abnormalities of bone turnover or arthropathy, the effects on knee joint tissue by IS has not been investigated yet. The present studies have been carried out to test the IS effects on synovial fibroblasts, meniscal fibrochond...

Better quality of cartilage repair in developing skeleton is recognized. The associated repair factors may be important in osteoarthritis and those factors would be the targets for the management of osteoarthritis. Microarray analysis of cartilage repair in rat knee joint was therefore carried out. Surgical injury on the femoral cartilage of the right patello-femoral joint in the 3- and 8-week-old rats for 2 weeks was first made. The left side of joint cartilage was used as th...

Destruction of the articular cartilage is the major feature of Osteoarthritis (OA). Ageing is the primary risk factor, but how ageing results in OA is still an enigma. In OA, articular chondrocytes degrade their own matrix, while in healthy articular cartilage they preserve it.Transforming growth factor β (TGFβ) is a central regulator of chondrocyte proliferation, differentiation and extracellular matrix production. Deregulation of TGFβ si...

It is well-established that in vitro differentiation of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) can recapitulate embryonic development through germ layer induction, enrichment and expansion of specific lineages. We have used PSC technology and developed a novel, mESC differentiation system for investigating the mechanisms of chondrocyte and osteoblast lineage commitment and differentiation. This step-wise, serum-free protocol uses specif...