Concordance of judgement: A tool to foster the development of professionalism in dentistry.

INTRODUCTION: Developing professionalism notably involves learning how to make professional judgements in ambiguous situations. The Concordance of Judgement Test (CJT) is a learning tool that was proposed to develop professionalism competencies, but it was never performed in dentistry or used with a synchronous methodology. The present study evaluated the feasibility of the use of CJT in the context of dental education, to foster professionalism and stimulate reflexivity and discussion. MATERIALS AND METHODS: After different steps of optimization, a questionnaire presenting 12 vignettes was submitted to 33 Canadian students. Second, after an additional optimization, a questionnaire of 7 vignettes was submitted to 87 French students. An immediate educational feedback was proposed after each vignette to promote reflexivity and discussions during the experience. RESULTS: The overall experience of the students was reported as good, thanks to the feedback of real-life situations. This promoted reflexivity and stimulated discussion between students and educators regarding professionalism issues. The students considered CJT as a relevant and well-adapted tool, and reported positive feelings regarding the inter-university aspect of the activity. The mean score of the panel members was close to 80/100 and the mean score of the students was 5 to 10 points lower, which is in agreement with docimological performance. CONCLUSION: The results suggested that the use of CJT in a synchronous way was a feasible and relevant tool to motivate the students to improve their professionalism, and to stimulate their reflexivity and discussion. The students reported positive experience with CJT, and we believe that this tool can be integrated in the dental curriculum.

Management of dental care of patients on immunosuppressive drugs for chronic immune-related inflammatory diseases: a survey of French dentists' practices.

OBJECTIVES: The aim of the study was to provide an overview of the practices of French general dentists (GDs) and specialists (SDs) concerning the management of patients with inflammatory bowel diseases (IBDs), rheumatic inflammatory diseases (IRDs), and vasculitis on biologic disease-modifying antirheumatic drugs (bDMARDs), conventional DMARDs, or immunosuppressants (ISs). MATERIALS AND METHODS: An online national cross-sectional survey with 53 questions was developed by a multidisciplinary team including rheumatologists, gastroenterologists and dentists based on their clinical experience. It was refined following a test with nine dentists in private practice and in hospital before being disseminated to the members of French scientific societies and colleges of dentistry teachers over 3 months. Responses of general dentists versus specialists were compared with respect to their experience in managing patients with IRDs or IBDs, knowledge/training, type of invasive procedure performed, management of medical treatment, perioperative oral-care protocols, and frequency of postoperative complications after invasive dental care procedures. RESULT: In total, 105 practitioners fully completed the survey (participation rate 11.1%). SDs more frequently performed invasive surgical procedures and were more aware of the recommendations of learned societies than GDs. They encountered more post-operative complications for patients on bDMARDs. For both SDs and GDs, most patients were managed without stopping treatment and pre- and postoperative antibiotics were prescribed to more than 75% of patients. When medical treatment was stopped, the decision was made by the prescribing physician. CONCLUSION: Complications were reported more frequently by SDs when highly invasive procedures were performed on patients under active drug therapy. Certain common procedures, such as scaling and root planing, appear to be safe, regardless of treatment management. However, adapted guidelines for the practice of dentistry are needed to standardize the management of patients on bDMARDS, conventional DMARDs, or ISs. CLINICAL RELEVANCE: French dentists perform a wide range of oral procedures on patients on bDMARDS, conventional DMARDs, or ISs under antibiotic coverage and antiseptic mouthwashes. SDs reported more postoperative complications after extensive invasive procedures for patients under active drug therapy, despite their greater knowledge of recommendations on how to manage such patients.

Disease activity and patient reported outcome measures in Sjögren's - what are the best tools to evaluate?

In primary SS (pSS), clinical features in SS can be divided into two facets: the patient perceived manifestations such as dryness, pain and fatigue, and the systemic manifestations. In the past decades, with efforts made by an international collaboration, consensual clinical indexes were developed for assessing both facets: one patient reported outcome, the EULAR SS Patients Reported Index (ESSPRI), and one activity index for systemic manifestations, the EULAR SS Disease Activity Index (ESSDAI). In addition, objective measures were developed to quantify the importance and consequence of ocular and oral dryness, few being specific of pSS. Work is ongoing to develop indexes combining all these approaches. Recent changes in the assessment of pSS patients, and the emergence of new targeted therapies, have put a greater emphasis on the design of clinical trials in pSS, and led for the first time to a positive randomized clinical trial.

OSCEGame: A serious game for OSCE training.

BACKGROUND: Objective Structured Clinical Examinations (OSCEs) are amongst the most anxiety-provoking competency assessment methods. An online serious game (OSCEGame) was developed and implemented within the OSCE curriculum. This study aimed to evaluate the usefulness of this serious game on preparedness and reducing OSCE-related stress. METHODS: A serious game was designed to help dental students train for OSCEs. Two game courses (4 stations each) were designed according to year of undergraduate training (4th and 5th year), based on 6 pre-existing multi-competency OSCE stations. The OSCEGame was available online on a learning platform 4 to 6 weeks before the summative OSCEs. Game use was evaluated by analysing connection data. Preparedness, stress and time management skills were assessed using a questionnaire following the summative OCSEs. The results of 4th -year students (OSCE naive population) were compared to those of 5th -year students to assess usefulness and benefits of such preparation method. RESULTS: In total, 97% and 60% of the students in 4th year and 5th year, respectively, used the game. The game was seen as an essential preparation tool to reduce anxiety (for 60% of all students) and increase time management skills (65% of all students). However, significant differences were observed between 4th- and 5th -year students (anxiety reduction: 65% vs. 22%, p < 0.001; time management skills: 59% vs. 41%, p < 0.05) suggesting that it is most useful for OSCE naive students. CONCLUSION: This serious game is a useful time efficient online tool, for OSCE preparation, especially in OSCE naive students.

NAMPT expression in osteoblasts controls osteoclast recruitment in alveolar bone remodeling.

In bone remodeling, osteoclasts are recruited via increased production of RANKL (receptor activator of nuclear factor-κB ligand) and migrate to the bone surface, aided by matrix metalloproteinases (MMPs). NAMPT (nicotinamide phosphoribosyl transferase), which catalyzes the rate-limiting step in the NAD+ salvage pathway, increases during in vitro osteogenic differentiation and inhibits RANKL-induced osteoclast differentiation. Alveolar bone loss, due to disturbance of the remodeling process, is a major feature of periodontitis. Thus, we investigated the role of NAMPT in a synchronized alveolar bone remodeling rat model. NAMPT expression increased in osteogenic cells during the remodeling activation phase, in parallel with RANKL and MMP-2 expression. Inhibition of NAMPT activity, by systemic delivery of its selective inhibitor FK866, decreased the recruitment of osteoclasts, but not their activity. In vitro, NAMPT mRNA, and protein expression also increased during osteoblast differentiation in primary calvarial osteoblast cultures. Recombinant NAMPT and NMN, its direct metabolite, dose-dependently increased bone marker expression, including that of sialoprotein (BSP) and osteocalcin (OC), whereas their expression was inhibited by FK866 treatment. Recombinant NAMPT did not regulate MMP-2, -9, MMP-13, or RANKL/OPG mRNA expression in osteoblasts. Our data suggest that de novo NAMPT synthesis in osteoblasts controls cell differentiation through osteoclast recruitment during the activation of bone remodeling.

Identification of soluble 14-3-3∊ as a novel subchondral bone mediator involved in cartilage degradation in osteoarthritis.

OBJECTIVE: Mechanical stress plays an important role in cartilage degradation and subchondral bone remodeling in osteoarthritis (OA). The remodeling of the subchondral bone could initiate cartilage loss in OA through the interplay of bone and cartilage. The aim of this study was to identify soluble mediators released by loaded osteoblasts/osteocytes that could induce the release of catabolic factors by chondrocytes. METHODS: Murine osteoblasts/osteocytes were subjected to cyclic compression, and then conditioned medium from either compressed (CCM) or uncompressed (UCM) cells was used to stimulate mouse chondrocytes. Chondrocyte expression of matrix metalloproteinase 3 (MMP-3), MMP-13, type II collagen, and aggrecan was assessed by reverse transcription-polymerase chain reaction, Western blotting, and enzyme-linked immunosorbent assay. Soluble mediators released by compressed osteoblasts/osteocytes were identified using iTRAQ (isobaric tags for relative and absolute quantification), a differential secretome analysis. Subchondral bone and cartilage samples were isolated from OA patients, and culture medium conditioned with OA subchondral bone or cartilage was used to stimulate human chondrocytes. RESULTS: Stimulation of mouse chondrocytes with CCM strongly induced the messenger RNA (mRNA) expression and protein release of MMP-3 and MMP-13 and inhibited the mRNA expression of type II collagen and aggrecan. Differential secretome analysis revealed that 10 proteins were up-regulated in compressed osteoblasts/osteocytes. Among them, soluble 14-3-3∊ (s14-3-3∊) dose-dependently induced the release of catabolic factors by chondrocytes, mimicking the effects of cell compression. Addition of a 14-3-3∊ blocking antibody greatly attenuated the CCM-mediated induction of MMP-3 and MMP-13 expression. Furthermore, in human OA subchondral bone, s14-3-3∊ was strongly released, and in cultures of human OA chondrocytes, s14-3-3∊ stimulated MMP-3 expression. CONCLUSION: The results of this study identify s14-3-3∊ as a novel soluble mediator critical in the communication between subchondral bone and cartilage in OA. Thus, s14-3-3∊ may be a potential target for future therapeutic or prognostic applications in OA.

Engaging student analysis of the practitioner-patient relationship assessed with reflective outcomes.

The representations and beliefs of both patient and practitioner influence the relationship that develops between them. We developed an innovative, interactive teaching tool in two stages (1- interviews with the patient or healthcare practitioner and 2- a session with sharing of the patient's and practitioner's perspective) whose objectives are to recognize the basic characteristics of PPR and identify how it can be influenced by expectations, beliefs and emotions. This pedagogical device was particularly appreciated by the students, as it enabled them to identify the importance of the patient's point of view and to reflect on their future professional identity.

Immune Checkpoint Inhibitor-induced Sicca Syndrome.

The development of sicca in patients treated with immune checkpoint inhibitors (ICIs) is undoubtedly an underestimated complication, but one whose functional consequences and impact on quality of life are significant for patients. This update aims to review the frequency of this complication and different clinical pictures. The authors also propose a diagnostic and therapeutic approach to guide clinicians in daily practice.

[Periodontitis : An underestimated risk of cardiovascular diseases]. / La parodontite : un risque sous-estimé des maladies cardiovasculaires.

Epidemiological studies have identified periodontitis as a contributing factor to cardiovascular risk. Periodontitis is a chronic inflammatory disease that affects the tissues supporting the teeth. Although the nature of the association between periodontitis and cardiovascular disease (CVD) remains to be defined, the low-grade systemic inflammation and chronic bacteremia associated with periodontitis appear to be involved in the development of atherosclerosis and associated cardiovascular pathologies. Periodontal treatment has been shown to improve cardiovascular health parameters. A bidirectional preventive approach, involving the management of both periodontitis and cardiovascular risk factors, could lead to a reduction in morbidity and mortality related to cardiovascular disease.

Title: La parodontite : un risque sous-estimé des maladies cardiovasculaires. Abstract: Les études épidémiologiques identifient la parodontite, maladie inflammatoire chronique des tissus de soutien des dents, comme un facteur contribuant au risque cardiovasculaire. Bien que la nature de l'association entre parodontite et maladies cardio-vasculaires (MCV) reste à définir (causalité ou corrélation), l'inflammation systémique de bas grade et les bactériémies chroniques qui sont associées aux parodontites apparaissent impliquées dans le développement de l'athérosclérose et des maladies cardio-vasculaires associées. Le traitement parodontal semble contribuer à l'amélioration des paramètres de la santé cardiovasculaire. Dès lors, une approche de prévention bidirectionnelle, impliquant à la fois la gestion de la parodontite et des facteurs de risque cardiovasculaire, pourrait permettre une réduction de la morbidité et de la mortalité liées aux MCV.

Proinflammatory actions of visfatin/nicotinamide phosphoribosyltransferase (Nampt) involve regulation of insulin signaling pathway and Nampt enzymatic activity.

Visfatin (also termed pre-B-cell colony-enhancing factor (PBEF) or nicotinamide phosphoribosyltransferase (Nampt)) is a pleiotropic mediator acting on many inflammatory processes including osteoarthritis. Visfatin exhibits both an intracellular enzymatic activity (nicotinamide phosphoribosyltransferase, Nampt) leading to NAD synthesis and a cytokine function via the binding to its hypothetical receptor. We recently reported the role of visfatin in prostaglandin E(2) (PGE(2)) synthesis in chondrocytes. Here, our aim was to characterize the signaling pathways involved in this response in exploring both the insulin receptor (IR) signaling pathway and Nampt activity. IR was expressed in human and murine chondrocytes, and visfatin triggered Akt phosphorylation in murine chondrocytes. Blocking IR expression with siRNA or activity using the hydroxy-2-naphthalenyl methyl phosphonic acid tris acetoxymethyl ester (HNMPA-(AM)(3)) inhibitor diminished visfatin-induced PGE(2) release in chondrocytes. Moreover, visfatin-induced IGF-1R(-/-) chondrocytes released higher concentration of PGE(2) than IGF-1R(+/+) cells, a finding confirmed with an antibody that blocked IGF-1R. Using RT-PCR, we found that visfatin did not regulate IR expression and that an increased insulin release was also unlikely to be involved because insulin was unable to increase PGE(2) release. Inhibition of Nampt activity using the APO866 inhibitor gradually decreased PGE(2) release, whereas the addition of exogenous nicotinamide increased it. We conclude that the proinflammatory actions of visfatin in chondrocytes involve regulation of IR signaling pathways, possibly through the control of Nampt enzymatic activity.

Stress-induced cartilage degradation does not depend on the NLRP3 inflammasome in human osteoarthritis and mouse models.

OBJECTIVE: The main feature of osteoarthritis (OA) is degradation and loss of articular cartilage. Interleukin-1ß (IL-1ß) is thought to have a prominent role in shifting the metabolic balance toward degradation. IL-1ß is first synthesized as an inactive precursor that is cleaved to the secreted active form mainly in the "inflammasome," a complex of initiators (including NLRP3), adaptor molecule ASC, and caspase 1. The aim of this study was to clarify the roles of IL-1ß and the inflammasome in cartilage breakdown. METHODS: We assessed IL-1ß release by cartilage explants from 18 patients with OA. We also evaluated the lipopolysaccharide (LPS)-, IL-1α-, and tumor necrosis factor α (TNFα)-induced activity of matrix metalloproteinase 3 (MMP-3), MMP-9, and MMP-13 in NLRP3-knockout mice and wild-type mice and the inhibition of caspase 1 with Z-YVAD-FMK and the blockade of IL-1ß with IL-1 receptor antagonist (IL-1Ra). Cartilage explants from NLRP3-knockout mice and IL-1R type I (IL-1RI)-knockout mice were subjected to excessive dynamic compression (0.5 Hz, 1 MPa) to trigger degradation, followed by assessment of load-induced glycosaminoglycan (GAG) release and MMP enzymatic activity. RESULTS: Despite the expression of NLRP3, ASC, and caspase 1, OA cartilage was not able to produce active IL-1ß. LPS, IL-1α, and TNFα dose-dependently increased MMP-3, MMP-9, and MMP-13 activity in cultured chondrocytes and in NLRP3(-/-) chondrocytes, and this effect was not changed by inhibiting caspase 1 or IL-1ß. The load-induced increase in GAG release and MMP activity was not affected by knockout of NLRP3 or IL-1RI in cartilage explants. CONCLUSION: OA cartilage may be degraded independently of any inflammasome activity, which may explain, at least in part, the lack of effect of IL-1ß inhibitors observed in previous trials.

[Inflammatory diseases of the salivary]. / Pathologies inflammatoires des glandes salivaires.

INFLAMMATORY DISEASES OF THE SALIVARY GLANDS. Salivary glands can be affected by inflammatory pathologies. They are most often manifested by the occurrence of swelling of the main salivary glands that can be associated with a dryness. Main inflammatory diseases with salivary gland involvement are Sjögren's disease, IgG4-associated disease and sarcoidosis. These diseases are rare and characterized by systemic involvement. The existence of multiple organ involvement must lead to the diagnosis. The first step in the diagnostic process is to eliminate the much more frequent differential diagnoses, primarily lithiasis and infectious diseases, as well as nutritional causes. In case of suspicion, a biopsy of the minor salivary glands may help to advance the etiological investigation.

glandes salivaires peuvent être le siège de pathologies inflammatoires. Celles-ci se manifestent le plus souvent par la survenue du gonflement des glandes salivaires principales, parfois associé à un syndrome sec. Les principales pathologies inflammatoires avec atteinte des glandes salivaires sont le la maladie de Sjögren, la maladie associée aux IgG4 et la sarcoïdose. Ces maladies sont des pathologies rares avec atteintes systémiques ; l'existence d'atteintes d'organes multiples doit en faire évoquer le diagnostic. La démarche diagnostique élimine dans un premier temps les pathologies lithiasiques et infectieuses, plus fréquentes, ainsi que les causes nutritionnelles. En cas de suspicion, la réalisation d'une biopsie des glandes salivaires accessoires permet d'avancer dans l'enquête étiologique.

Managing the sexualization of the dentist-patient relationship by the patient: Innovative teaching through forum-theatre.

Dental students may be exposed to patients' sexual behavior. We developed a theater-forum session whose aims were to identify when the patient's behavior crosses the line, to collectively develop cover strategies, and to present the reporting system. The strategies pointed out by the group were to ask a pair to be present, set limits on personal life, share discomfort to the patient and report the situation to the staff. Theater-forum is a powerful tool for this learning process.

Inhibition of matrix metalloproteinase-3 and -13 synthesis induced by IL-1beta in chondrocytes from mice lacking microsomal prostaglandin E synthase-1.

Joint destruction in arthritis is in part due to the induction of matrix metalloproteinase (MMP) expression and their inhibitors, especially MMP-13 and -3, which directly degrade the cartilage matrix. Although IL-1ß is considered as the main catabolic factor involved in MMP-13 and -3 expression, the role of PGE(2) remains controversial. The goal of this study was to determine the role of PGE(2) on MMP synthesis in articular chondrocytes using mice lacking microsomal PGE synthase-1 (mPGES-1), which catalyses the rate-limiting step of PGE(2) synthesis. MMP-3 and MMP-13 mRNA and protein expressions were assessed by real-time RT-PCR, immunoblotting, and ELISA in primary cultures of articular chondrocytes from mice with genetic deletion of mPGES-1. IL-1ß-induced PGE(2) synthesis was dramatically reduced in mPGES-1(-/-) and mPGES-1(+/-) compared with mPGES-1(+/+) chondrocytes. A total of 10 ng/ml IL-1ß increased MMP-3 and MMP-13 mRNA, protein expression, and release in mPGES-1(+/+) chondrocytes in a time-dependent manner. IL-1ß-induced MMP-3 and MMP-13 mRNA expression, protein expression, and release decreased in mPGES-1(-/-) and mPGES-1(+/-) chondrocytes compared with mPGES-1(+/+) chondrocytes from 8 up to 24 h. Otherwise, MMP inhibition was partially reversed by addition of 10 ng/ml PGE(2) in mPGES-1(-/-) chondrocytes. Finally, in mPGES-1(-/-) chondrocytes treated by forskolin, MMP-3 protein expression was significantly decreased compared with wild-type, suggesting that PGE(2) regulates MMP-3 expression via a signaling pathway dependent on cAMP. These results demonstrate that PGE(2) plays a key role in the induction of MMP-3 and MMP-13 in an inflammatory context. Therefore, mPGES-1 could be considered as a critical target to counteract cartilage degradation in arthritis.

The influence of non-carious lesions in the surgical treatment of gingival recession: A systematic review & meta-analysis.

BACKGROUND: The presence of a non-carious cervical lesion (NCCL) is a complicating factor for tooth coverage following gingival recession. It is generally associated with disappearance of the enamel-cementum junction, a key landmark, and a surface discrepancy requiring restoration or compensation using a connective tissue graft (CTG). The aim of this systematic review is to study the efficacy of periodontal plastic surgery on recession defects associated with a NCCL, with or without restorative treatment. MATERIALS AND METHODS: RCT assessing the root coverage of teeth with Miller's class I and class II isolated gingival recession with an NCCL published up to April 2020, with at least 10 patients per group and a follow-up longer than 6 months, were included through electronic databases and hand-searched journals. RESULTS: Seven articles were finally included. Treatment systematically consisted of a coronally advanced flap in association with partial or complete restorative treatment ± CTG. Meta-analyses showed that periodontal plastic procedures are less effective in terms of complete root coverage in cases of teeth with an NCCL. Overall Mean Recession Reduction was 2.00 mm (CI: [1.72, 2.28]), and overall mean complete root coverage was 5% (CI: [2,8]). CONCLUSION: The presence of an NCCL is a complicating factor in plastic surgery. The use of CTG without NCCL restoration provides better outcomes except for the reduction of dental hypersensitivity for which the combined treatment (restoration + CTG) is the most effective.

NLRP3 Is Involved in Neutrophil Mobilization in Experimental Periodontitis.

The NLRP3 inflammasome is overexpressed in gingiva of periodontitis patients but its role remains unclear. In our study, we use a periodontitis mouse model of ligature, impregnated or not with Porphyromonas gingivalis, in WT or NLRP3 KO mice. After 28 days of induction, ligature alone provoked exacerbated periodontal destruction in KO mice, compared to WT mice, with an increase in activated osteoclasts. No difference was observed at 14 days, suggesting that NLRP3 is involved in regulatory pathways that limit periodontitis. In contrast, in the presence of P. gingivalis, this protective effect of NLRP3 was not observed. Overexpression of NLRP3 in connective tissue of WT mice increased the local production of mature IL-1ß, together with a dramatic mobilization of neutrophils, bipartitely distributed between the site of periodontitis induction and the alveolar bone crest. P. gingivalis enhanced the targeting of NLRP3-positive neutrophils to the alveolar bone crest, suggesting a role for this subpopulation in bone loss. Conversely, in NLRP3 KO mice, mature IL-1ß expression was lower and almost no neutrophils were mobilized. Our study sheds new light on the role of NLRP3 in periodontitis by highlighting the ambiguous role of neutrophils, and P. gingivalis which affects NLRP3 functions.

Periodontal and dental health in inflammatory bowel diseases: a systematic review.

Introduction: An increased risk of dental caries and periodontal diseases has been reported for inflammatory bowel disease (IBD) patients and are challenging conditions to manage.Areas covered: The authors searched international databases to find all studies assessing dental/periodontal outcomes in patients with IBD and other immune-mediated inflammatory disease (IMID), as well as the association between IMID medications and dental/periodontal status.Expert opinion: IBD are associated with a higher risk of both periodontitis and caries. Some evidence from rheumatoid arthritis suggests that periodontitis may be associated with a lower response to anti-TNF. There is no reliable evidence that IBD patients may be at greater risk of complications during routine dental care. On the basis of current data, guidelines can be proposed for the dental management focusing on the detection and eradication of infectious foci prior to the implementation of immunosuppressants/biologics and modified dental treatment protocol for invasive dental procedures that includes antibiotic prophylaxis.

Antibiotic Use in Periodontal Therapy among French Dentists and Factors Which Influence Prescribing Practices.

The aim of the present survey is to investigate the use of antibiotics during periodontal therapy among French dentists with a focus on exploring potential differences between various groups of practitioners. A self-administered questionnaire was distributed to different groups of practitioners including members of (i) the French Society of Periodontology and Implantology; (ii) the College of University Teachers in Periodontology and, (iii) private practitioners participating in the French general dental practice-based research network. 272 questionnaires were included in the analysis. Prescription patterns were globally in line with the current recommendations. Systemic antibiotics are most frequently used as a first-line therapy in necrotizing periodontitis (92%) and aggressive periodontitis (53.3% to 66.1%). However, malpractice still exists, including in the management of periodontal abscesses. Antibiotics are prescribed (i) less frequently for periodontal abscesses and (ii) more frequently for generalized aggressive periodontitis by members of the periodontal society and University college (p < 0.05). Amoxicillin (59.9%) and the amoxicillin + metronidazole (59.6%) combination were the most frequently prescribed molecules. Providing a high number of periodontal treatments per week, being more recently graduated, having a post-graduate certificate in periodontology and holding or having held an academic position/hospital practice were all factors associated with a better knowledge of and/or more adequate antibiotic use.

Mechanical stress and prostaglandin E2 synthesis in cartilage.

Knee osteoarthritis (OA) results, at least in part, from overloading and inflammation leading to cartilage degradation. Prostaglandin E2 (PGE2) is one of the main catabolic factors involved in OA in which metalloproteinase (MMP) is crucial for cartilage degradation. Its synthesis is the result of cyclooxygenase (COX) and prostaglandin E synthase (PGES) activities whereas NAD+-dependent 15 hydroxy-prostaglandin dehydrogenase (15-PGDH) is the key enzyme implicated in the catabolism of PGE2. Among the isoforms described, COX-1 and cytosolic PGES are constitutively expressed whereas COX-2 and microsomal PGES type 1 (mPGES-1) are inducible in an inflammatory context. We investigated the regulation of the COX, PGES and 15-PGDH and MMP-2, MMP-9 and MMP-13 genes by mechanical stress applied to cartilage explants. Mouse cartilage explants were subjected to compression (0.5 Hz, 1 MPa) from 2 to 24 h. After determination of the PGE2 release in the media, mRNA and proteins were extracted directly from the cartilage explants and analyzed by real-time RT-PCR and western blot respectively. Mechanical compression of cartilage explants significantly increased PGE2 production in a time dependent manner. This was not due to the synthesis of IL-1, since pretreatment with IL1-Ra did not alter the PGE2 synthesis. Interestingly, COX-2 and mPGES-1 mRNA expression significantly increased after 2 hours, in parallel with protein expression. Moreover, we observed a delayed overexpression of 15-PGDH just before the decline of PGE2 synthesis after 18 hours suggesting that PGE2 synthesis could be altered by the induction of 15-PGDH expression. MAPK are involved in signaling, since specific inhibitors partially inhibited COX-2 and mPGES-1 expressions. Lastly, compression induced MMP-2, -9, -13 mRNA expressions in cartilage. We conclude that dynamic compression induces pro-inflammatroy mediators release and matrix degradating enzymes synthesis. Notably, compression increases mPGES-1 mRNA and protein expression in cartilage explants. Thus, the mechanosensitive mPGES-1 enzyme represents a potential therapeutic target in osteoarthritis.