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Objectives Osteoarthritis is a painful joint disease responsible for walking impairment. Its quantitative assessment by gait analysis in mice may be a relevant and noninvasive strategy to assess the disease severity. In this study, we aimed to determine the severity of osteoarthritis at the tissular and gait levels in unilateral and bilateral posttraumatic murine osteoarthritis. Methods Twenty-four C57BL/6 male mice were randomly assigned to 3 groups ( n = 8/group): controls, unilateral surgery, and bilateral surgery. Posttraumatic osteoarthritis was induced unilaterally or bilaterally by destabilization of the medial meniscus. Gait analysis was performed weekly with the CatWalkTM XT system until the 16th week after surgery. After animal sacrifices, histological and micro–computed tomographic assessment was performed. Results Operated knees showed a significant increase in the histological score compared with controls ( P < 0.001). Calcified anterior medial meniscal bone volume was higher on the ipsilateral side after unilateral destabilization of the medial meniscus ( P < 0.001) and on both sides after bilateral intervention ( P < 0.01). One week after surgery, the mice mean speed decreased significantly in both operated groups ( P < 0.001 and P < 0.05). In the unilateral group, a significant increase in the contralateral hind print area appeared from week 4 to week 16. Conclusions While bilateral destabilization of the medial meniscus induced no detectable gait modification except 1 week after surgery, unilateral model was responsible for a gait disturbance on the contralateral side. Further studies are needed to better define the place of the CatWalkTM in the evaluation of mouse models of osteoarthritis.

Mesenchymal stem/stromal cells (MSCs) have been widely used for their therapeutic properties in many clinical applications including osteoarthritis. Despite promising preclinical results showing the ability of MSC to reduce the clinical severity of osteoarthritis (OA) in experimental animal models, the benefits of intra-articular injection of MSC in OA patients are limited to the short term. In this regard, it is anticipated that improving the properties of MSC may collectively enhance their long-term beneficial effects on OA.Recently, we have shown that PPARWe designed and synthesized an interfering peptide that potently and specifically blocks PPAR

Some patients with moderate haemophilia (PWMH) report joint damage potentially responsible for gait disorders. Three-dimensional gait analysis (3DGA) is a relevant tool for the identification of complex musculoskeletal impairment. We performed an evaluation with 3DGA of 24 PWMH aged 44.3 ± 16.1 according to their joint status [Haemophilia Joint Health Score (HJHS) < 10 or HJHS ≥ 10] and assessed the correlation with the radiological and clinical parameters. Sixteen had HJHS < 10 (group 1) and eight had HJHS ≥ 10 (group 2). They were compared to 30 healthy subjects of a normative dataset. Both knee and ankle gait variable scores were increased in group 2 compared to the controls (p = 0.02 and p = 0.04, respectively). The PWMH of group 2 had a significant increase in their stance phase, double support duration, and stride width compared to the controls and group 1 (p < 0.01). Very low correlations were found for the ankle gait variable score with the ankle Pettersson sub-score (r2 = 0.250; p = 0.004) and ankle HJHS sub-score (r2 = 0.150; p = 0.04). For the knee, very low correlation was also found between the knee gait variable score and its HJHS sub-score (r2 = 0.290; p < 0.0001). Patients with moderate haemophilia presented a gait alteration in the case of poor lower limb joint status.

International audience; Introduction: Knee joint bleedings are responsible for quadriceps atrophy and strength deficit in patients with severe haemophilia. Little is known about patients with moderate haemophilia (PWMH).Aim: To evaluate isokinetic quadriceps and hamstrings strength in PWMH and to assess correlation with radiological and clinical parameter.Methods: 18 PWMH aged 37.1 ± 11.4 and 18 healthy age-, weight- and height-matched controls performed a knee isokinetic test at 180°/s to assess quadriceps and hamstrings strength. In the PWMH group, knee Pettersson's score was pursued and Haemophilia Joint Health Score 2.1 (HJHS) was performed to determine unaffected knees (knee HJHS = 0) and affected ones (knee HJHS >0).Results: Affected knees had a decrease of quadriceps strength compared to controls, 1.26 ± 0.47 vs 1.64 ± 0.27 Nm/kg and a decrease of hamstring strength, 0.60 ± 0.29 vs 1.03 ± 0.21 Nm/kg, (P < 0.001). Unaffected knees also had a decrease of quadriceps strength compared to controls, 1.36 ± 0.31 vs 1.64 ± 0.27 Nm/kg and a decrease of hamstring strength, 0.69 ± 0.18 vs 1.03 ± 0.21 Nm/kg, (P < 0.001). The conventional hamstring-to-quadriceps ratio was significantly decreased in affected knees compared to controls, 0.46 ± 0.15 vs 0.64 ± 0.13 (P < 0.001) but also in unaffected knees, 0.53 ± 0.16 vs 0.64 ± 0.13 (P = 0.02).No correlation was found between strength and HJHS or Pettersson's score.Conclusion: PWMH have a significant knee strength deficit, both on the quadriceps and the hamstrings, which is responsible for an important muscle imbalance.

Osteoarthritis affects hundreds of millions of people worldwide, and its prevalence is constantly increasing. While there is no effective treatment to date, new promising therapeutic strategies and targets are being investigated. Innovative cell therapies are reaching clinical trials, and the most recent progress in our understanding of the pathology is opening new routes for gene therapy. In the long term, the development of new biofabrication tools such as 3D bioprinting might pave the way for the use of personalized mini-joint models that would allow clinicians to screen drugs and personalize treatments. This review offers an overview of the most promising therapeutic approaches in the field of osteoarthritis, from coming treatments to those that are yet to be discovered., L’arthrose affecte des centaines de millions de personnes à travers le monde et sa prévalence ne fait qu’augmenter. Si aucun traitement ne permet de stopper le développement de l’arthrose à ce jour, de nouvelles stratégies et cibles thérapeutiques sont à l’étude. Ainsi, alors que des thérapies cellulaires de nouvelle génération font d’ores et déjà l’objet d’études cliniques, l’amélioration de la compréhension de cette pathologie ouvre la voie à de possibles thérapies géniques. À plus long terme, le développement d’outils de biofabrication tels que la bio-impression 3D permettent d’entrevoir l’utilisation de modèles personnalisés de mini-articulations pour le criblage de principes actifs et l’application de traitements sur mesure. Cette revue propose un tour d’horizon des approches thérapeutiques les plus prometteuses pour traiter l’arthrose, des traitements à venir à ceux qu’il reste à découvrir.

Summary Objective TGFβ is a key player in cartilage homeostasis and OA pathology. However, few data are available on the role of TGFβ signalling in the different OA phenotypes. Here, we analysed the TGFβ pathway by transcriptomic analysis in six mouse models of OA. Method We have brought together seven expert laboratories in OA pathophysiology and, used inter-laboratories standard operating procedures and quality controls to increase experimental reproducibility and decrease bias. As none of the available OA models covers the complexity and heterogeneity of the human disease, we used six different murine models of knee OA: from post-traumatic/mechanical models (meniscectomy (MNX), MNX and hypergravity (HG-MNX), MNX and high fat diet (HF-MNX), MNX and seipin knock-out (SP-MNX)) to aging-related OA and inflammatory OA (collagenase-induced OA (CIOA)). Four controls (MNX-sham, young, SP-sham, CIOA-sham) were added. OsteoArthritis Research Society International (OARSI)-based scoring of femoral condyles and ribonucleic acid (RNA) extraction from tibial plateau samples were done by single operators as well as the transcriptomic analysis of the TGFβ family pathway by Custom TaqMan® Array Microfluidic Cards. Results The transcriptomic analysis revealed specific gene signatures in each of the six models; however, no gene was deregulated in all six OA models. Of interest, we found that the combinatorial Gdf5-Cd36-Ltbp4 signature might discriminate distinct subgroups of OA: Cd36 upregulation is a hallmark of MNX-related OA while Gdf5 and Ltbp4 upregulation is related to MNX-induced OA and CIOA. Conclusion These findings stress the OA animal model heterogeneity and the need of caution when extrapolating results from one model to another.

International audience; Haemophilia is characterized by a congenital deficiency of clotting factor VIII or IX. One of the consequences of haemophilia is joint bleedings. Repetitive haemathroses induce cartilage damage and chronic synovitis leading to joint deterioration, and to definitive haemophilic arthropathy which is source of walking disability. Three-dimension gait analysis (3DGA) appears particularly relevant in the case of haemophilia because it allows an evaluation of several joints in weight-bearing situations. The purpose of this study was to review the interest and the contribution of 3DGA in the management of patients with haemophilia. The greatest interest of gait analysis would be to detect early walking changes with a non-invasive and well-tolerated examination, especially in paediatric population. In adulthood, this technic may be also useful to help detect walking worsening in patients known to have already arthropathy. However, it takes time to realize and needs expensive equipment, which limits its possibility of routine use. Although generalizations of these results remain difficult,especially to compare patients with haemophilia to normal population. Indeed, in the studies, patient groups are small and usually heterogeneous in terms of age and target joints. It certainly results of the rarity of the disease. So, it could be interesting to perform a study with a larger cohort in order to allow subgroup analysis, helping to define clearly the place of 3DGA in the strategy of haemophilia evaluation.

International audience; Osteoarthritis affects hundreds of millions of people worldwide, and its prevalence is constantly increasing. While there is currently no treatment that can alter the course of the disease, promising therapeutic strategies and novel targets are being investigated. Innovative cell therapies are already reaching clinical trials, and recent progress in our understanding of the disease is opening new routes for gene therapy. In the long term, the development of new biofabrication tools, such as 3D bioprinting, may pave the way for personalized mini-joint models that could be used to screen drugs and to personalize treatments. This review provides an overview of the most promising therapeutic approaches in the field of osteoarthritis, from upcoming treatments to those that are yet to be discovered.

International audience; Osteoarthritis (OA) is a degenerative and inflammatory joint disease that affects the cartilage, subchondral bone, and joint tissues. Although current drug therapies can provide a degree of symptomatic relief from pain, they fail to prevent joint damage. Mesenchymal stem/stromal cells (MSCs) have generated significant interest in terms of medical applications because they exert their therapeutic properties by secretion of bioactive factors that have potent immunomodulatory, antiapoptotic, antifibrotic, and anti-inflammatory effects. However, intra-articular injection of MSCs has major limitations including cell death upon injection and massive leakage from the injection site. Encapsulation of MSCs has therefore been developed as a way to overcome these limitations and to deliver therapeutic bioactive factors in several pathologies. In this review, we first briefly highlight the main therapeutic properties of MSCs and their applications in OA treatment. We then focus on MSC encapsulation and the current advances this strategy offers for the treatment of OA.

Polyphenols are widely acknowledged for their health benefits, especially for the prevention of inflammatory and age-related diseases. We previously demonstrated that hydroxytyrosol (HT) and procyanidins (PCy), alone or in combination, drive preventive anti-osteoathritic effects in vivo. However, the lack of sufficient clinical evidences on the relationship between dietary phytochemicals and osteoarthritis remains. In this light, we investigated in humans the potential osteoarticular benefit of a grapeseed and olive extract (OPCO) characterized for its hydroxytyrosol (HT) and procyanidins (PCy) content. We first validated, in vitro, the anti-inflammatory and chondroprotective properties of the extract on primary cultured human articular chondrocytes stimulated by interleukin-1 beta (IL-1 &beta, ). The sparing effect involved a molecular mechanism dependent on the nuclear transcription factor-kappa B (NF-&kappa, B) pathway. To confirm the clinical relevance of such a nutritional strategy, we designed an innovative clinical approach taking into account the metabolites that are formed during the digestion process and that appear in circulation after the ingestion of the OPCO extract. Blood samples from volunteers were collected following ingestion, absorption, and metabolization of the extract and then were processed and applied on human primary chondrocyte cultures. This original ex vivo methodology confirmed at a clinical level the chondroprotective properties previously observed in vitro and in vivo.

International audience; Current protocols for chondrocyte expansion and chondrogenic differentiation of stem cells fail to reduce phenotypic loss and to mitigate hypertrophic tendency. To this end, cell genetic manipulation is gaining pace as a means of generating cells with stable chondrocyte phenotype. Herein, we provide an overview of candidate genes that either induce cartilage regeneration or inhibit cartilage degeneration. We further discuss in vitro, ex vivo and in vivo viral transduction and non-viral transfection strategies for targeted cells (chondrocytes, me-senchymal stem cells, induced pluripotent stem cells and synovial cells), along with the most representative results obtained in pre-clinical models and in clinical trials. We highlight current challenges and associated risks that slowdown clinical acceptance and commercialisation of gene transfer technologies.

Introduction Owing to their ability to secrete anti-inflammatory and immuno-modulatory factors Mesenchymal Stromal Cells (MSCs) are an attractive tool for the treatment of osteoarthritis. Considering cell death and the risk of cell leakage upon intra-articular injection, MSCs encapsulation therefore could protect cell from death, avoid cell effusion outside the articular space, and supply a suitable 3D microenvironment supporting the biological activity of MSCs. Objectives Our objective was to develop a method of MSC encapsulation compatible with their intra-articular injection through a 26G needle. Methods Human adipose-derived stem cells (hASCs) were encapsulated via a micromolding method. We first manufactured polydimethylsiloxane chips containing 1600 micromolds with a circular shape, 150 µm in diameter and 100 µm in depth. For cell encapsulation, a solution of 2% alginate (w/v) containing 3 million of hASCs per mL polymer was deposited onto the chips, loaded in the moulds either by sedimentation or centrifugation and crosslinked using an agarose gel charged with CaCl2. The number of encapsulated cells was evaluated by a CyQUANT assay immediately and 24 hour after encapsulation. The impact of encapsulation on metabolic activity was determined by a presto blue assay 24 hours after encapsulation and 24 hour after their injection through a 26G needle. Results We successfully obtained cylindrical alginate microparticles presenting a diameter of 103±0.7 µm. Using cell quantification, we determined that the centrifugation method allowed the encapsulation of 30 333 (±5552) cells within one chip versus 6056 (±2862) by sedimentation. Cell number and metabolic activity remained stable for 24 hours after encapsulation. We also demonstrated that injection through a 26G needle had no impact on the viability of encapsulated cells. Conclusions Our results show that micromolding allows hASCs encapsulation into alginate particles injectable through a 26 G needle without impacting cell viability. Future work will focus on evaluating in vitro long-term encapsulated cell survival and functionality. In case of success, we will then consider intra-articular injection in an animal model of osteoarthritis. Disclosure of interest None declared

Introduction The pathogenesis of OA is not fully characterised, but is thought to be due to perturbation of chondrocytes homeostasis including an impairment in the autophagy process particularly during ageing. Among the anti-ageing factors, Klotho has been shown to regulate autophagy in a variety of cell types, and Klotho polymorphisms have been associated with higher risks of OA. Objectives The aim of this project was to investigate the role of Klotho in OA. Methods The expression of Klotho and autophagy markers (LC3b and Beclin-1) and OA onset were evaluated in ageing C57BL/6 mice as an age-related spontaneous model of OA. The cartilage integrity, autophagy and apoptosis status in Klotho-deficient mice knee joints were also analysed. In parallel, to investigate the relationship between Klotho and autophagy, immature murine articular chondrocytes (iMACs) were stimulated with increasing doses of soluble recombinant Klotho. The effect of Klotho on autophagy was also evaluated in a pathological context, i.e. following IL1-β stimulation (10 ng/ml) for 24 hours. Bax/Bcl-2 ratio, a marker of the intrinsic apoptotic pathway, was also evaluated in IL1-β-treated chondrocytes. Results In the knee joints of mice from escalating ages, the expression of Klotho correlated with LC3b and Beclin-1 expression and gradually decreased with age while OA features appear. Articular cartilage of KL-/- mice revealed an increase in the OARSI score, associated with increased chondrocyte death and LC3b expression, as well as caspase 3 and TUNEL expression. In IL1-β-treated chondrocytes, the autophagy markers and Bax/Bcl-2 ratio were overexpressed, while the addition of Klotho counteracted this effect. Conclusions In summary, we described an early articular cartilage degradation in the absence of Klotho, suggesting a potential protective role of Klotho in OA development. The increase in autophagic process in Klotho mutant mice associated with the decrease in autophagy and Klotho expression with age clearly indicate intimate relationships between these two players. In vitro experiments suggested that Klotho may not have a direct effect on autophagy but rather through reducing apoptosis induced by pro-inflammatory cytokines such as IL1-β. Our study revealed the close relationship between the anti-ageing Klotho protein and chondrocyte death in articular cartilage, unveiling Klotho as a potential target to enhance chondrocyte survival. Disclosure of interest None declared

International audience

The development of biologically and mechanically competent hydrogels is a prerequisite in cartilage engineering. We recently demonstrated that a marine exopolysaccharide, GY785, stimulates the in vitro chondrogenesis of adipose stromal cells. In the present study, we thus hypothesized that enriching our silated hydroxypropyl methylcellulose hydrogel (Si-HPMC) with GY785 might offer new prospects in the development of scaffolds for cartilage regeneration. The interaction properties of GY785 with growth factors was tested by surface plasmon resonance (SPR). The biocompatibility of Si-HPMC/GY785 towards rabbit articular chondrocytes (RACs) and its ability to maintain and recover a chondrocytic phenotype were then evaluated in vitro by MTS assay, cell counting and qRT-PCR. Finally, we evaluated the potential of Si-HPMC/GY785 associated with RACs to form cartilaginous tissue in vivo by transplantation into the subcutis of nude mice for 3 weeks. Our SPR data indicated that GY785 was able to physically interact with BMP-2 and TGFβ. Our analyses also showed that three-dimensionally (3D)-cultured RACs into Si-HPMC/GY785 strongly expressed type II collagen (COL2) and aggrecan transcripts when compared to Si-HPMC alone. In addition, RACs also produced large amounts of extracellular matrix (ECM) containing glycosaminoglycans (GAG) and COL2. When dedifferentiated RACs were replaced in 3D in Si-HPMC/GY785, the expressions of COL2 and aggrecan transcripts were recovered and that of type I collagen decreased. Immunohistological analyses of Si-HPMC/GY785 constructs transplanted into nude mice revealed the production of a cartilage-like extracellular matrix (ECM) containing high amounts of GAG and COL2. These results indicate that GY785-enriched Si-HPMC appears to be a promising hydrogel for cartilage tissue engineering. Copyright © 2015 John Wiley & Sons, Ltd.

Mesenchymal stem cells-containing alginate particles for intra-articular injection in osteoarthritis. World Congress of the Osteoarthritis-Research-Society-International

Peter Ratcliffe,1,2 Peppi Koivunen,3 Johanna Myllyharju,3 Jiannis Ragoussis,4 Judith VMG Bovée,5 Ines Batinic-Haberle,6 Claire Vinatier,7 Valérie Trichet,8 Florence Robriquet,9 Lisa Oliver,9 Betty Gardie9,10 1Target Discovery Institute, University of Oxford, 2The Francis Crick Institute, London, UK; 3Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland; 4McGill University and Genome Quebec Innovation Centre, McGill University, Montreal, Canada; 5Department of Pathology, Leiden University Medical Center, Leiden, the Netherlands; 6Department of Radiation Oncology, Duke University School of Medicine, Durham, NC, USA; 7INSERM UMR 1229, Regenerative Medicine and Skeleton-RMeS, Team STEP, University of Nantes, UFR Odontology, 8UMR 1238 INSERM, Université de Nantes, Faculté de Médecine, 9CRCINA, INSERM, Université de Nantes, Nantes, 10Ecole Pratique des Hautes Etudes, PSL Research University, Paris, France Abstract: The “Hypoxia Nantes 2016” organized its second conference dedicated to the field of hypoxia research. This conference focused on “the role of hypoxia under physiological conditions as well as in cancer” and took place in Nantes, France, in October 6–7, 2016. The main objective of this conference was to bring together a large group of scientists from different spheres of hypoxia. Recent advances were presented and discussed around different topics: genomics, physiology, musculoskeletal, stem cells, microenvironment and cancer, and oxidative stress. This review summarizes the major highlights of the meeting. Keywords: hypoxia, genomics, lipid metabolism, musculoskeletal, cancer, oxidative stress&nbsp

International audience; Alteromonas infernus bacterium isolated from deep-sea hydrothermal vents can produce by fermentation a high molecular weight exopolysaccharide (EPS) called GY785. This EPS described as a new source of glycosaminoglycan-like molecule presents a great potential for pharmaceutical and biotechnological applications. However, this unusual EPS is secreted by a Gram-negative bacterium and can be therefore contaminated by endotoxins, in particular the lipopolysaccharides (LPS). Biochemical and chemical analyses of the LPS extracted from A. infernus membranes have shown the lack of the typical LPS architecture since 3-deoxy-D-manno-oct-2-ulopyranosonic acid (Kdo), glucosamine (GlcN), and phosphorylated monosaccharides were not present. Unlike for other Gram-negative bacteria, the results revealed that the outer membrane of A. infernus bacterium is most likely composed of peculiar glycolipids. Furthermore, the presence of these glycolipids was also detected in the EPS batches produced by fermentation. Different purification and chemical detoxification methods were evaluated to efficiently purify the EPS. Only the method based on a differential solubility of EPS and glycolipids in deoxycholate detergent showed the highest decrease in the endotoxin content. In contrast to the other tested methods, this new protocol can provide an effective method for obtaining endotoxin-free EPS without any important modification of its molecular weight, monosaccharide composition, and sulfate content.

International audience; Osteoarthritis (OA) is a degenerative joint disease that, despite recent progress, has no curative treatment. Considerable research has recently been initiated to identify new potential therapeutic targets. In this review, we will set forth some of the major discoveries in the past 5 years, notably those dealing with the identification of pathogenic factors [hypoxia-inducible factors (HIFs), complement, transforming growth factor (TGF)-β and zinc-ZIP8]. New drugs and concepts currently in clinical development [anti-nerve growth factor (NGF), mesenchymal stromal cells and fibroblast growth factor (FGF)-18] will then be addressed. Finally, we will consider prospective avenues that could lead to mid-to-long-term developments of novel therapeutic concepts, notably those dealing with autophagy regulation and induced pluripotent stem cells.

International audience; Articular cartilage is a non-vascularized and poorly cellularized connective tissue that is frequently damaged as a result of trauma and degenerative joint diseases such as osteoarthrtis. Because of the absence of vascularization, articular cartilage has low capacity for spontaneous repair. Today, and despite a large number of preclinical data, no therapy capable of restoring the healthy structure and function of damaged articular cartilage is clinically available. Tissue-engineering strategies involving the combination of cells, scaffolding biomaterials and bioactive agents have been of interest notably for the repair of damaged articular cartilage. During the last 30 years, cartilage tissue engineering has evolved from the treatment of focal lesions of articular cartilage to the development of strategies targeting the osteoarthritis process. In this review, we focus on the different aspects of tissue engineering applied to cartilage engineering. We first discuss cells, biomaterials and biological or environmental factors instrumental to the development of cartilage tissue engineering, then review the potential development of cartilage engineering strategies targeting new emerging pathogenic mechanisms of osteoarthritis.

International audience

The authors are grateful to B. Fellah, I. Leborgne, and P. Roy (CRIP-ONIRIS) who contributed to experiments using rabbits; S. Sourice (Inserm UMRS 791) for her advice with histological analysis; E. Hay (Inserm UMRS 1132) for his advice with NITEGE IHC; P.Pilet for his fruitful discussion for IHC intensity analysis; F. Berenbaum for his help in DMM mice model; UTE Platform (SFR Francois Bonamy, FED 4203/ Inserm UMS 016/CNRS 3556) who provided daily care to animals and specially P. Monmousseau who provided help with forced-fed rabbits; MS and NMR experiments were undertaken at the Metabolome Facility at the Functional Genomic Center in Bordeaux, France and specially E. Renouf for her assistance in UPLC-MS analysis. R Pace who provided help with manuscript. This study was supported by Grap'Sud, Region Languedoc Roussillon, the BPI and the ANRT; International audience; Polyphenols exert a large range of beneficial effects in the prevention of age-related diseases. We sought to determine whether an extract of olive and grape seed standardized according to hydroxytyrosol (HT) and procyanidins (PCy) content, exerts preventive anti-osteoathritic effects. To this aim, we evaluated whether the HT/PCy mix could (i) have in vitro anti-inflammatory and chondroprotective actions, (ii) exert anti-osteoarthritis effects in two post-traumatic animal models and (iii) retain its bioactivity after oral administration. Anti-inflammatory and chondroprotective actions of HT/PCy were tested on primary cultured rabbit chondrocytes stimulated by interleukin-1 beta (IL-1β). The results showed that HT/PCy exerts anti-inflammatory and chondroprotective actions in vitro. The preventive effect of HT/PCy association was assessed in two animal models of post-traumatic OA in mice and rabbits. Diet supplementation with HT/PCy significantly decreased the severity of post-traumatic osteoarthritis in two complementary mice and rabbit models. The bioavailability and bioactivity was evaluated following gavage with HT/PCy in rabbits. Regular metabolites from HT/PCy extract were found in sera from rabbits following oral intake. Finally, sera from rabbits force-fed with HT/PCy conserved anti-IL-1β effect, suggesting the bioactivity of this extract. To conclude, HT/PCy extract may be of clinical significance for the preventive treatment of osteoarthritis.

This study describes an innovative experimentally induced model of intervertebral disc degeneration. This innovative approach is based on the induction of extracellular matrix disorders in the intervertebral disc (IVD) using a diode laser. For this study, 15 one-year-old and five 30-month-old New Zealand White rabbits were used. Two procedures were tested to trigger IVD degeneration: needle aspiration (reference technique) and a laser approach. The IVD degeneration process was assessed 20, 40, 60, 90 and 120 days after surgery by X-ray radiography (IVD height), magnetic resonance imaging (MRI) (T2 intensity of IVD signal) and histological analysis using modified Boos’ scoring. Our data indicate that a marked IVD degeneration was found compared with sham-operated animals regardless of the procedure tested. A significant decrease in disc height on X-ray radiographs was first demonstrated. In addition, MRI disc signals were significantly reduced in both groups. Finally, a statistically significant increase in Boos’ scoring was found in both laser and aspiration-induced IVD degeneration. Interestingly, IVD degeneration induced by laser treatment was more progressive compared with aspiration. Moreover, the histological results indicated that laser-induced disc degeneration was quite similar to that obtained during the natural aging process as observed in 30-month-old rabbits. Our study describes the consistency of this innovative experimentally-induced animal model of IVD degeneration. The radiological, MRI and histological data confirm its relevance. The histological examination indicates that IVD degeneration induced by laser treatment is comparable to the degenerative process observed during the onset of spontaneous IVD degeneration. This model could be a useful tool to help us validate biomaterial-assisted, cell-based, regenerative medicine strategies for the prevention and treatment of IVD degeneration.

Resume Le cartilage articulaire est un tissu conjonctif non innerve, non vascularise et faiblement cellularise. Il peut etre le siege de nombreuses alterations d’origine traumatologique ou liee au vieillissement. Ce tissu possede de faibles capacites de cicatrisation spontanee et l’etablissement de ces alterations se manifeste aux stades terminaux par la perte du role fonctionnel des articulations. La derniere decennie a permis le developpement de nouvelles technologies permettant de stimuler les capacites intrinseques de reparation du cartilage. Malheureusement, l’ensemble de ces technologies n’a pas demontre de succes clinique satisfaisant. Dans ce contexte, la regeneration du cartilage par ingenierie tissulaire est aujourd’hui consideree avec un interet croissant. En particulier, le transfert de cellules reparatrices autologues a l’aide de biomateriaux synthetiques apparait prometteur. Nous avons ainsi developpe et brevete un hydrogel biocompatible de cellulose silanisee autoreticulant pouvant etre utilise comme un vecteur injectable pour la medecine regeneratrice. Ainsi, nos etudes portent sur l’association de cet hydrogel avec une source de cellules reparatrices, les cellules souches mesenchymateuses (CSM) adultes derivees du tissu adipeux. Dans un premier temps, nous avons determine les conditions de culture optimales necessaires a l’orientation chondrogenique des cellules souches (morphogenes, hypoxie, trois dimensions…). L’interet preclinique de nos associations hybrides cellules et materiaux a ensuite ete teste avec succes dans differents modeles animaux (souris, lapin). La medecine regeneratrice et l’ingenierie tissulaire basees sur l’utilisation de cellules souches et d’hydrogel pourraient permettre d’ouvrir de nouvelles fenetres therapeutiques dans le traitement de ces atteintes dont le vieillissement de la population ne fait qu’accroitre l’impact socioeconomique.

Mesenchymal stem cells (MSCs) are considered as an attractive source of cells for cartilage engineering due to their availability and capacity for expansion and multipotency. Differentiation of MSC into chondrocytes is crucial to successful cartilage regeneration and can be induced by various biological agents, including polysaccharides that participate in many biological processes through interactions with growth factors. Here, we hypothesize that growth factor-induced differentiation of MSC can be increased by chemically oversulfated marine polysaccharides. To test our hypothesis, human adipose tissue-derived MSCs (hATSCs) were cultured in pellets with transforming growth factor (TGF)-beta 1-supplemented chondrogenic medium containing either the polysaccharide GY785 DR or its oversulfated isoform GY785 DRS. Chondrogenesis was monitored by the measurement of pellet volume, quantification of DNA, collagens, glycosaminoglycans (GAGs), and immunohistological staining. Our data revealed an increase in pellet volume, total collagens, and GAG production with GY785 DRS and chondrogenic medium. The enhanced chondrogenic differentiation of hATSC was further demonstrated by the increased expression of several chondrogenic markers by real-time reverse transcription-polymerase chain reaction. In addition, surface plasmon resonance analyses revealed that TGF-beta 1 bound GY785 DRS with higher affinity compared to GY785 DR. In association with TGF-beta 1, GY785 DRS was found to upregulate the phosphorylation of extracellular signal-regulated kinase 1/2, indicating that oversulfated polysaccharide affects the mitogen activated protein kinase signaling activity. These results demonstrate the upregulation of TGF-beta 1-dependent stem cell chondrogenesis by a chemically oversulfated marine polysaccharide. This polysaccharide of marine origin is easily producible and therefore could be considered a promising additive to drive efficient and reliable MSC chondrogenesis for cartilage tissue engineering. STEM CELLS 2012;30:471-480

International audience; Human adipose tissue-derived stem cells (hATSC) have been contemplated as reparative cells for cartilage engineering. Chondrogenic differentiation of hATSC can be induced by an enriched culture medium and a three-dimensional environment. Given that bone is vascularized and cartilage is not, oxygen tension has been suggested as a regulatory factor for osteochondrogenic differentiation. Our work aimed at determining whether hypoxia affects the osteochondrogenic potential of hATSC. hATSC were cultured in chondrogenic or osteogenic medium for 28 days, in pellets or monolayers, and under 5% or 20% oxygen tension. Cell differentiation was monitored by real-time PCR (COL2A1, aggrecan, Runx2, and osteocalcin). The chondrogenic differentiation was further evaluated by Alcian blue and immunohistological staining for glycosaminoglycans (GAGs) and type II collagen, respectively. Osteogenic differentiation was also assessed by the staining of mineralized matrix (Alizarin Red) and measurement of alkaline phosphatase (ALP) activity. The expression of chondrogenic markers was upregulated when hATSC were exposed to hypoxia in chondrogenic medium. Conversely, osteocalcin expression, mineralization, and ALP activity were severely reduced under hypoxic conditions even in the presence of osteogenic medium. Our data strongly suggest that hypoxia favors the chondrogenic differentiation of hATSC as evidenced by the expression of the chondrogenic markers, whereas it could alter their osteogenic potential. Our results highlight the differential regulatory role of hypoxia on the chondrogenic and osteogenic differentiation processes of hATSC. These data could help us exploit the potential of tissue engineering and stem cells to replace or restore the function of osteoarticular tissues.

Lowbackpainhasalifetimeprevalenceof80%inthegeneralpopulation and causes a huge public health burden in industri-alized countries. The most common cause of low back pain isdegenerativediseaseoftheintervertebraldiscs(IVDs).Theeco-nomic impact of low back pain is tremendous, with estimateddirect and indirect costs of 20 to 100billion dollars per year inthe US [1]. Symptomatic treatment is rarely sufficient and newtherapeutic approaches are therefore needed, most notably tocounteractthedegenerativeprocess.Formanyyears,researchershave been working on methods to regenerate the Nucleus pulpo-sus (NP), the central component of the IVD. Among the severalapproaches suggested to date, tissue engineering is consideredpromising by clinicians. Tissue engineering involves replac-ing the damaged tissue by a biomaterial and appropriate cells.Preclinical studies are under way, and the place for tissue engi-neeringinthetherapeuticmanagementforlowbackpainisbeingdefined.

The purpose of this study was to compare bone reconstruction using either mesenchymal stem cells (MSCs) or total bone marrow (TBM) in association with biphasic calcium phosphate (BCP) granules after irradiation in a rat model. Three weeks after an external irradiation of the hind limbs of rats, four bone defects were created per animal. The defects were filled with either BCP alone, or with a mixture of BCP and TBM, or with a mixture of BCP and MSCs (adipose-derived or bone marrow-derived MSCs). Three weeks after implantations, new-bone formation was assessed. Histological examination showed osteoconductive and osteointegrative properties of BCP in irradiated tissue. The BCP-TBM mixture significantly improved bone ingrowth (p

We have developed a self-reticulating polymer based on silanized hydroxypropylmethylcellulose (Si-HPMC). The aim of this study was to determine whether this Si-HPMC hydrogel with or without calcium phosphate granules could represent a potential scaffold for bone tissue engineering. This study showed that Si-HPMC hydrogel didn't affect SaOS-2 and rat bone marrow cells viability. In addition, SaOS-2 cells are able to proliferate within Si-HPMC hydrogel containing or not calcium phosphate granules whereas Rat bone marrow cells proliferate only at the surface of calcium phosphate granules contained within Si-HPMC hydrogel. Finally, SaOS-2 cells seeded at the surface of reticulated Si-HPMC were not able to penetrate the hydrogel, while J774, a macrophage cells line, were able to move into the Si-HPMC hydrogel. These data indicate that Si-HPMC is a promissing scaffold for tissue engineering.