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BackgroundChondrocytes in osteoarthritic (OA) cartilage acquire a hypertrophic-like phenotype, where Hedgehog (Hh) signaling is pivotal. Hh overexpression causes OA-like cartilage lesions, whereas its downregulation prevents articular destruction in mouse models. Mutations in EVC and EVC2 genes disrupt Hh signaling, and are responsible for the Ellis-van Creveld syndrome skeletal dysplasia. Since Ellis-van Creveld syndrome protein (Evc) deletion is expected to hamper Hh target gene expression we hypothesized that it would also prevent OA progression avoiding chondrocyte hypertrophy. Our aim was to study Evc as a new therapeutic target in OA, and whether Evc deletion restrains chondrocyte hypertrophy and prevents joint damage in an Evc tamoxifen induced knockout (EvccKO) model of OA.MethodsOA was induced by surgical knee destabilization in wild-type (WT) and EvccKO adult mice, and healthy WT mice were used as controls (n=10 knees/group). Hypertrophic markers and Hh genes were measured by qRT-PCR, and metalloproteinases (MMP) levels assessed by western blot. Human OA chondrocytes and cartilage samples were obtained from patients undergoing knee joint replacement surgery. Cyclopamine (CPA) was used for Hh pharmacological inhibition and IL-1β as an inflammatory insult.ResultsTamoxifen induced inactivation of Evc inhibited Hh overexpression and partially prevented chondrocyte hypertrophy during OA, although it did not ameliorate cartilage damage in DMM-EvccKO mice. Hh pathway inhibition did not modify the expression of proinflammatory mediators induced by IL-1 beta in human OA chondrocytes in culture. Hypertrophic – IHH – and inflammatory – COX-2 – markers co-localized in OA cartilage samples.ConclusionsTamoxifen induced inactivation of Evc partially prevented chondrocyte hypertrophy in DMM-EvccKO mice, but it did not ameliorate cartilage damage. Our results suggest that chondrocyte hypertrophy per se is not a pathogenic event in the progression of OA.

Summary Objective We aimed to assess whether an increase in chondrocyte size might be a feature of the articular cartilage (AC) hypertrophic-like phenotype both in experimental and in human osteoarthritis (OA). The anatomical location of these enlarged cells in the cartilage layers was also evaluated. Methods Experimental OA was carried out in female rabbits alone or in combination with osteoporosis (OPOA). The rabbits were subjected to destabilization knee surgery to develop OA. Osteoporosis was induced with ovariectomy and methylprednisolone administration. Human OA samples obtained from knee replacement surgery were also studied. Cartilage lesions and chondrocyte size were assessed in AC sections. Immunostaining of type-X collagen and metalloproteinase-13 were used as markers of the AC hypertrophic transformation. Both the cell size and the gene expression of type-X collagen were further analyzed in primary murine chondrocyte cultures. Results Compared to healthy AC, chondrocyte size was increased both in experimental and in human OA, in correlation with the severity of cartilage damage. No differences in chondrocyte size were found between deeper or more superficial regions of AC. In cell cultures, accretion of hypertrophic markers and cell enlargement were found to occur synchronized. Conclusions We observed an enhancement in the mean size of chondrocytes at the OA cartilage, which showed correlation with cartilage damage, both in human and in experimental OA. The enlarged chondrocytes were homogeneously distributed throughout the AC. Our results suggest that chondrocyte size could be a reliable measure of disease progression, of potential use in the histopathological assessment of OA cartilage.

Summary The major histocompatibility complex (MHC) class I-related chain A (MICA) is induced upon stress, and labels malfunctioning cells for their recognition by cytotoxic lymphocytes. Alterations in this recognition and also abnormal natural killer (NK) functions have been found in systemic lupus erythematosus (SLE). MICA can be shed from cells, subsequently acting as a soluble decoy receptor (sMICA). Our purpose was to study circulating sMICA levels in relationship with the activation of innate pathways in PBMC in a cohort of lupus patients. NK cells were characterized by flow cytometry. Gene expression of Toll-like receptors (TLR), interferon (IFN)-I sensitive genes and MICA were separately analyzed in monocytes, T cells and B cells. Serum sMICA was measured with enzyme-linked immunosorbent assay (ELISA). In our cohort, NK cell counts dropped in relationship with disease activity. sMICA showed an inverse trend with NK cell counts, as well as a significant association with activity indices, but not with complement decrease. Levels of sMICA associated to proteinuria and active nephritis. A multivariate regression model revealed anti-nuclear antibody (ANA) titres, the up-regulation of TLR-4 in T cells and lower vitamin D as predictors of sMICA enhancement. Interestingly, vitamin D showed an inverse association with proteinuria and a strong correlation with T cell MICA mRNA levels. According to our data, circulating sMICA identifies a subgroup of lupus patients with low vitamin D, innate activation of T cells and nephritis. We propose that lymphocyte shedding could account for the enhancement of sMICA and reflect an immune evasion mechanism driving disease activation in lupus.

Background: Bone alterations have been observed in the course of HIV infection, char-acterized by a marked decrease in bone mineral density (BMD) and an increase in the frequency of fractures as a result of fragility. We aim to evaluate early changes in bone metabolic profile and the possible association with tenofovir and other nucleoside and nucleotide reverse transcriptase inhibi-tors (NRTIs) in treatment-naïve HIV patients. Methods: We conducted a prospective study in naïve HIV-infected adults (under 50 years), separat-ed into three groups according to NRTI therapy: tenofovir disoproxil fumarate (TDF); tenofovir alafenamide (TAF) and abacavir (ABC). BMD and epidemiological, immunological and metabolic bone parameters were evaluated. Bone markers were analyzed in plasma at baseline, 12 and 48 weeks after initiating treatment. Results: Average age of patients was 34.8 years (± 9.6). 92.4% of them with CD4 count > 200 cel/μL. At week 12 after starting treatment, both TDF [increase in PN1P (31.7%, p = 0.004), TRAP (11.1%, p = 0.003), OPN (19.3%, p = 0.045) and OC (38.6%, p = 0.001); decrease in OPG (-23.4%, p = 0.003)] and TAF [increase in 42.6% for CTX (p = 0.011), 27.3% for OC (p = 0.001) and 21% for TRAP (p = 0.008); decrease in OPG (-28.8%, p = 0.049)] presented a deep resorption profile compared to ABC, these differences in bone molecular markers, a tendency to equalize at week 48, where no significant differences were observed. Patients treated with TDF showed the greatest decrease in Z-score in both lumbar spine (LS) and femoral neck (FN) at week 48 without statistically significant differences. Conclusion: Treatment-naïve HIV patients have a high prevalence of low bone density. Treatment with TDF is associated with greater bone deterioration at 12 and 48 weeks. TAF seems to present similar early bone deterioration at 12 weeks which disappears at 48 weeks., This research was financially supported by The Carlos III Health Institute through the “Miguel Servet” program (CP15/00053), co-funded by The European Regional Development Fund and research grants from the Spanish Carlos III Health Institute (PI16/00991 and PI19/00744)

ObjectiveTo evaluate the discriminatory ability of ultrasound in calcium pyrophosphate deposition disease (CPPD), using microscopic analysis of menisci and knee hyaline cartilage (HC) as reference standard.MethodsConsecutive patients scheduled for knee replacement surgery, due to osteoarthritis (OA), were enrolled. Each patient underwent ultrasound examination of the menisci and HC of the knee, scoring each site for presence/absence of CPPD. Ultrasound signs of inflammation (effusion, synovial proliferation and power Doppler) were assessed semiquantitatively (0–3). The menisci and condyles, retrieved during surgery, were examined microscopically by optical light microscopy and by compensated polarised microscopy. CPPs were scored as present/absent in six different samples from the surface and from the internal part of menisci and cartilage. Ultrasound and microscopic analysis were performed by different operators, blinded to each other’s findings.Results11 researchers from seven countries participated in the study. Of 101 enrolled patients, 68 were included in the analysis. In 38 patients, the surgical specimens were insufficient. The overall diagnostic accuracy of ultrasound for CPPD was of 75%—sensitivity of 91% (range 71%–87% in single sites) and specificity of 59% (range 68%–92%). The best sensitivity and specificity were obtained by assessing in combination by ultrasound the medial meniscus and the medial condyle HC (88% and 76%, respectively). No differences were found between patients with and without CPPD regarding ultrasound signs of inflammation.ConclusionUltrasound demonstrated to be an accurate tool for discriminating CPPD. No differences were found between patents with OA alone and CPPD plus OA regarding inflammation.

We have read with interest the comment from Angelides and Manolios in which they propose an alternative way to account for the potential mechanism of action of glucosamine in osteoarthritis (OA) and other chronic inflammatory diseases.1 Recent and robust epidemiological data suggest that sustained glucosamine intake could partially prevent cardiovascular disease and cancer.2 Our editorial made some hypothetical considerations about the mechanism of action of this compound.3 The editorial also commented on the difficulty of detecting a beneficial effect of glucosamine in OA, due to the modesty of the therapeutic effect, as well as the weakness of the methodological tools employed in OA clinical trials.3 In some way, the relationship between glucosamine and OA takes us fully into the pathophysiology that revolves around immunometabolic regulation, a driver that can account for tissue deterioration in various chronic diseases and still with many aspects to …

Objective: Several studies have linked metabolic syndrome to the development of osteoarthritis (OA) through hypercholesterolemia, one of its components. However, epidemiological studies showed contradictory results, and it is not clear how hypercholesterolemia itself, or oxidized LDL (oxLDL)-a pathological molecule potentially involved in this relationship-could be affecting OA. The objectives of this study were to investigate the effect of hypercholesterolemia induced by high-fat diet (HFD) in cartilage from OA rabbits, and how oxLDL affect human chondrocyte inflammatory and catabolic responses. Design: New Zealand rabbits were fed with HFD for 18 weeks. On week 6, OA was surgically induced. At the end of the study, cartilage damage and IL-1β, IL-6, MCP-1, MMP-13, and COX-2 expression in articular cartilage were evaluated. In addition, cultured human OA articular chondrocytes were treated with oxLDL at concentrations equivalent to those expected in synovial fluid from HFD rabbits, in the presence of IL-1β and TNFα. The effect of oxLDL on cell viability, nitric oxide production and catabolic and pro-inflammatory gene expression was evaluated. Results: HFD intake did not modify cartilage structure or pro-inflammatory and catabolic gene expression and protein presence, both in healthy and OA animals. OxLDL did not affect human chondrocyte viability, ADAMTS5 and liver X receptor (LXR) α gene expression, but decreased the induction of IL-1β, IL-6, MCP-1, MMP-13, iNOS, and COX-2 gene expression and MMP-13 and COX-2 protein presence, evoked by cytokines. Conclusions: Our data suggest that cholesterol intake per se may not be deleterious for articular cartilage. Instead, cholesterol de novo synthesis and altered cholesterol metabolism could be involved in the associations observed in human disease.

Osteoarthritis (OA) is an evolving chronic joint disease with a huge global impact. Given the intricate nature of the etiopathogenesis and subsequent high heterogeneity in the clinical course of OA, it is crucial to discriminate between etiopathogenic endotypes and clinical phenotypes, especially in the early stages of the disease. In this sense, we propose that an OA phenotype should be properly assessed with a set of outcome measures including those specifically related to the main underlying pathophysiological mechanisms. Thus, each OA phenotype can be related to different and clinically meaningful outcomes. OA phenotyping would lead to an adequate patient stratification in well-designed clinical trials and the discovery of precise therapeutic approaches. A significant effort will be required in this field in light of inconclusive results of clinical trials of tissue-targeting agents for the treatment of OA.

Inflammation triggered by metabolic imbalance, also called metainflammation, is low-grade inflammation caused by the components involved in metabolic syndrome (MetS), including central obesity and impaired glucose tolerance. This phenomenon is mainly due to excess nutrients and energy, and it contributes to the pathogenesis of osteoarthritis (OA). OA is characterized by the progressive degeneration of articular cartilage, which suffers erosion and progressively becomes thinner. Purinergic signaling is involved in several physiological and pathological processes, such as cell proliferation in development and tissue regeneration, neurotransmission and inflammation. Adenosine and ATP receptors, and other members of the signaling pathway, such as AMP-activated protein kinase (AMPK), are involved in obesity, type 2 diabetes (T2D) and OA progression. In this review, we focus on purinergic regulation in osteoarthritic cartilage and how different components of MetS, such as obesity and T2D, modulate the purinergic system in OA. In that regard, we describe the critical role in this disease of receptors, such as adenosine A2A receptor (A2AR) and ATP P2X7 receptor. Finally, we also assess how nucleotides regulate the inflammasome in OA.

Osteoarthritis (OA) is a disease with a very long course and varied clinical expression in the initial stages, when it is really challenging to adequately measure disease outcomes both in clinical trials and in daily life.1 It is also very difficult to accurately study the efficacy of symptomatic slow-acting drugs for OA and that of non-pharmacological treatments.2 Although the efficacy of glucosamine (GlcN) in the treatment of OA is still a controversial issue3 4, recent high-quality epidemiological studies confirm previous data showing that prolonged GlcN intake, regardless of its effect on OA progression, could decrease cardiovascular disease (CVD) events, and the incidence of CVD-associated diseases.5–8 These data should be analysed keeping in mind that CVD is the main cause of death in patients with OA.9 Different authors suggest that this protective effect may be associated with the anti-inflammatory properties of GlcN,5 although the molecular basis has been only partially defined. The imbalance between the mechanical loading and its absorption by the articular cartilage is the origin of joint tissue alteration in OA. While a severe overload can deteriorate any kind of cartilage, a certain load that is physiologically well tolerated by a robust cartilage could be the origin of pathological alterations for a weakened one.9 Cartilage damage begins when the load prevails over the resistance, which in the midterm activates innate immune response in the different joint tissues, and is, at least partially, responsible for joint deterioration. Unbalanced mechanical forces and damage-associated molecular patterns turn on the innate immune system through the activation of the Toll-like receptors. Once this response is activated, a secondary wave of inflammatory mediators is released, with a robust increase in the concentration of cytokines and metalloproteases, the final effectors of cartilage destruction.9 Certainly, these mediators can …

Plasma levels of adenosine deaminase (ADA), an enzyme that deaminates adenosine to inosine, are increased during inflammation. An increase in ADA activity occurs with lower human immunodeficiency virus (HIV) viral load and higher CD4+ T cell counts. We aimed to investigate the role of plasma ADA as a biomarker of inflammation in treatment-na&iuml, ve HIV patients who received tenofovir or another nucleoside analog for comparison. Ninety-two treatment-na&iuml, ve patients were included in the study and grouped by treatment, i.e., tenofovir disoproxil fumarate (TDF), tenofovir alafenamide (TAF) or Triumeq. ADA activity was measured in plasma and cytokines were analyzed by MILLIPLEX&reg, MAP-Luminex&reg, Technology. Plasma concentration of monocytes and neutrophils was measured at 0, 3, and 12 months post-treatment. Treatment-na&iuml, ve HIV patients had increased ADA concentrations (over 15 U/L) that decreased after treatment with TAF and Triumeq, though this did not occur in TDF-treated patients. However, all groups exhibited a pro-inflammatory systemic profile at 12 months of treatment. Plasma GM-CSF levels decreased after 12 months of treatment in the TDF group, with a concomitant decrease in blood monocyte count, and a negative correlation with ADA values was found. In conclusion, ADA levels may be modulated by antiretroviral therapy in HIV patients, possibly affecting inflammatory status.

Osteoarthritis (OA) is a multifactorial joint disease mainly affecting articular cartilage (AC) with a relevant biomechanical component. During endochondral ossification growth plate (GP) chondrocytes arrange in columns. GPs do not ossify in skeletally mature rodents. In neonatal mice, an altered joint loading induces GP chondrocyte disorganization. We aimed to study whether experimental OA involves GP disorganization in adult mice and to assess if it may have additional detrimental effects on AC damage. Knee OA was induced by destabilization of the medial meniscus (DMM) in wild-type (WT) adult mice, and in Tamoxifen-inducible Ellis-van-Creveld syndrome protein (Evc) knockouts (EvccKO), used as a model of GP disorganization due to Hedgehog signalling disruption. Chondrocyte column arrangement was assessed in the tibial GP and expressed as Column Index (CI). Both DMM-operated WT mice and non-operated-EvccKO showed a decreased CI, indicating GP chondrocyte column disarrangement, although in the latter, it was not associated to AC damage. The most severe GP chondrocyte disorganization occurred in DMM-EvccKO mice, in comparison to the other groups. However, this altered GP structure in DMM-EvccKO mice did not exacerbate AC damage. Further studies are needed to confirm the lack of interference of GP alterations on the analysis of AC employing OA mice., This work was financially supported by grants from the Instituto de Salud Carlos III [PI15/00340, PI16/00065, PI18/00261] to RL and GH-B, and Fondo Europeo de Desarrollo Regional (FEDER) by grants SAF-2013–43365-R and SAF2016-75434-R to VL R-P. AL and PG were funded by Fundación Conchita Rábago.

The objective of this study was to validate musculoskeletal ultrasound (US) in a rabbit model of acute gout. Acute gout was induced by intra-articular injection of monosodium urate (MSU) crystals in 10 rabbits; the 3 controls received vehicle. Rabbit knees were assessed by B-mode and power Doppler (PD) US 24 and 72 h after injections. After 72 h, all rabbits were euthanized. US discriminated between the MSU-injected and control groups with respect to the different inflammatory findings at both at 24 and 72 h and for MSU crystal-related findings after 24 h of injection. US synovial thickening, intra-synovial power Doppler signal and global joint distension significantly correlated with the synovial global histopathological score (r = 0.47, p = 0.0188), tissue vascularization measured by CD31 immunohistochemical-positive staining (r = 0.46, p = 0.0172) and tissue levels of interleukin-1β (r = 0.53, p = 0.0078), respectively. US is a valid method for assessment of synovial inflammation in experimental gouty arthritis in rabbits.

BACKGROUND AND PURPOSE Patients with active rheumatoid arthritis (RA) have increased cardiovascular mortality, paradoxically associated with reduced circulating lipid levels. The Janus kinase (Jak) inhibitor tofacitinib ameliorates systemic and joint inflammation in RA with a concomitant increase in serum lipids. We analyzed the effect of tofacitinib on the lipid profile of hyperlipidemic rabbits with chronic arthritis (CA) and on the regulation of reverse cholesterol transport (RCT) during chronic inflammation. EXPERIMENTAL APPROACH CA was induced in previously immunized rabbits fed with a high-fat diet (HFD) by administering four intra-articular injections of ovalbumin. A group of rabbits received tofacitinib (10 mg kg-1 day-1) for two weeks. Systemic and synovial inflammation and lipid content were evaluated. For in vitro studies, THP-1-derived macrophages were exposed to high lipid concentrations, and then stimulated with interferon gamma (IFNγ) in the presence or absence of tofacitinib in order to study RCT mediators. KEY RESULTS Tofacitinib decreased systemic and synovial inflammation and increased circulating lipid levels. Although it did not modify synovial macrophage density, it was able to reduce the lipid content within synovial macrophages. In foam macrophages in culture, IFNγ further stimulated intracellular lipid accumulation, while Jak/STAT inhibition provoked by tofacitinib induced lipid release by increasing cellular liver X receptor alpha (LXRα) and ATP-binding cassette transporter (ABCA1) synthesis. CONCLUSION AND IMPLICATIONS Active inflammation could be associated with lipid accumulation within macrophages of CA rabbits. Jak inhibition induced lipid release though RCT activation, providing a plausible explanation for the effect of tofacitinib on the lipid profile of RA patients.

Background 9The OMERACT Ultrasound (US) in calcium pyrophosphate deposition disease (CPPD) sub-task force has been working on the assessment of the utility of US in CPPD since 2014 first creating definitions for CPPD identification and then demonstrating that US is a reliable tool[1]. Objectives Objective of this study is to assess the diagnostic accuracy of US in CPPD Methods This is a multicentre international diagnostic accuracy study involving 17 centres from 9 countries. We enrolled in this study consecutive patients waiting to undergo knee replacement surgery due to severe osteoarthritis. Each patient underwent US examination of the knee, focusing on the menisci and the hyaline cartilage, the day prior to surgery, scoring each site according to the presence/absence of CPP as defined by OMERACT[1]. After surgery, the menisci and the condyles were collected and examined microscopically. Six samples were collected, both from the surface and from the internal part of menisci and cartilage trying to cover a large part of the structure. All slides were observed under transmitted light microscopy and by compensated polarised microscopy. A dichotomous score was given for the presence/absence of CPP crystals. US and microscopic analysis were performed by blinded operators. Sensitivity and specificity of US were calculated using microscopic findings of the menisci and cartilage as the gold standard. Results These preliminary analyses include 30 patients. The mean age was 71yrs (SD±9.1), 19 (63%) were females. 17 patients were positive at US analysis and 12 at microscopic analysis. Diagnostic accuracy results of US at patient level, are presented in figure 1. Conclusion These preliminary results demonstrate that US is a sensitive exam for identification of CPPD with acceptable specificity. US is the first diagnostic technique with consistent reliability and validity to be applied for non-invasive screening for CPPD in clinical practice. References [1] Filippou G, Scire CA, Adinolfi A, et al. Identification of calcium pyrophosphate deposition disease (CPPD) by ultrasound: reliability of the OMERACT definitions in an extended set of joints—an international multiobserver study by the OMERACT Calcium Pyrophosphate Deposition Disease Ultrasound Subtask Force. Ann Rheum Dis 2018;:annrheumdis-2017-212542. doi:10.1136/annrheumdis-2017-212542 Disclosure of Interests Georgios Filippou Speakers bureau: Laborest, Abbvie, BMS, Sanofi, Anna Scanu: None declared, Antonella Adinolfi: None declared, Carmela Toscano: None declared, Raquel Largo-Carazo: None declared, Esperanza Naredo Consultant for: Abbvie, Speakers bureau: AbbVie, Roche, Bristol-Myers Squibb, Pfizer, UCB, Lilly, Novartis, Janssen, and Celgene GmbH, Emilio Calvo: None declared, Gabriel Herrero-Beaumont: None declared, Pascal Zufferey: None declared, Christel Madelaine-Bonjour: None declared, Daryl MacCarter: None declared, Stanley Makman: None declared, Zachary Weber: None declared, Ingrid Moller: None declared, Marwin Gutierrez: None declared, Carlos Pineda: None declared, Denise Clavijo Cornejo: None declared, Hector Garcia: None declared, Victor Ilizaliturri: None declared, Jaime Mendoza Torres: None declared, Raul Pichardo: None declared, Luis Carlos Rodriguez Delgado: None declared, Emilio Filippucci: None declared, Edoardo Cipolletta: None declared, Teodora Serban: None declared, Florentin Ananu Vreju Consultant for: abbvie and novartis, Speakers bureau: abbvie, novartis, pfizer, sandoz, eli lilly, ucb pharma, Gael Mouterde: None declared, Maria-Antonietta d’Agostino: None declared, Marcello Govoni: None declared, Leonardo Punzi Consultant for: BMS, Fidia, Grunenthal, Menarini, Speakers bureau: BMS, Fidia, Grunenthal, Menarini, Nemanja Damjanov Grant/research support from: AbbVie, Pfizer and Roche, Consultant for: Abbvie, Gedeon Richter, Merck, Novartis, Pfizer and Roche., Speakers bureau: Abbvie, Gedeon Richter, Merck, Novartis, Pfizer and Roche., Lene Terslev Speakers bureau: Speakers fee from : Roche, Novartis, Pfizer, MSD, BMS, Celgene, Irene Azzolin: None declared, Giulio Guerrini: None declared, Carlo Alberto Scire: None declared, Annamaria Iagnocco: None declared

Background: Patients with active rheumatoid arthritis (RA) have increased cardiovascular mortality, paradoxically associated with reduced circulating lipid levels (1-3). Several disease-modifying antirheumatic drugs (DMARDs), such as the JAK inhibitor tofacitinib, ameliorate disease activity along with an increase in serum lipids (4, 5). We previously demonstrated in vitro that tofacitinib favored cholesterol efflux from macrophages through an ABCA1-dependent mechanism (6). Furthermore, tofacitinib-treated chronic arthritic rabbits showed increased circulating lipids and decreased lipid accumulation within the synovium (6). Objectives: Our aim was to explore in vivo whether inflammation impedes cholesterol efflux from macrophages, and whether tofacitinib restores macrophage cholesterol release during chronic arthritis. For that purpose, we assessed the ability of intraperitoneally-injected 3H-cholesterol labelled macrophages to efflux cholesterol to circulating lipoproteins in collagen-induced arthritis (CIA) mice treated with tofacitinib or placebo, as compared to healthy controls. Methods: DBA/1J mice were randomly assigned to healthy controls (Control, n = 9), CIA (CIA, n = 6) and CIA mice receiving 50 mg/kg/day tofacitinib, orally, for three consecutive days, starting on day 39 after CIA induction and coinciding with disease peak (CIA+TOFA, n = 6). The day after, 3H-cholesterol labeled RAW264.7 macrophages were intraperitoneally injected into mice and tracer appearance was monitored in plasma lipoprotein subfractions, synovium, liver, bile and feces. Results: The CIA group showed higher C-Reactive protein levels (CRP, μg/ml; Control: 10.90±0.49, CIA: 13.86±1.05, p=0.03 vs. Control) and lower circulating 3H-cholesterol levels (% of injected disintegrations per minute (dpm)/ml; Control: 1.29±0.11, CIA: 0.92±0.11, p=0.04 vs. Control). Both serum CRP and 3H-cholesterol –particularly the HDL fraction– were restored to baseline after the treatment with the JAK inhibitor (CIA+TOFA: 10.97±0.67 μg/ml and 1.37±0.20 % of injected dpm/ml, respectively, p=0.05 vs. CIA). Concomitantly, we observed an upward trend in 3H-cholesterol accumulation within the synovium of CIA animals as compared to controls, which tended to normalize with the treatment. Conclusion: Systemic inflammation induces cholesterol sequestering within macrophages in vivo by acting on cholesterol efflux transporters (6). Tofacitinib favors cholesterol release to plasma lipoproteins, hence increasing circulating cholesterol. This is not only due to a decrease in inflammation –an effect very likely shared with some other biologic DMARDs–, but also to a direct mechanism on ABCA1 transporters that favors cholesterol efflux. To our knowledge, this is the first report suggesting that cholesterol dynamics in the macrophage may contribute to the overall circulating cholesterol levels, especially considering that this phenomenon may occur in other cell types, such as adipocytes. References [1] Johnsson H. et al. Ann Rheum Dis. 2013;73:1495–9. [2] Myasoedova E. et al. Ann Rheum Dis. 2012;70:482–7. [3] Choy E, Sattar N. Ann Rheum Dis. 2009;68:460–9. [4] Charles-Schoeman C. et al. Semin Arthritis Rheum. 2016;46:71–80. [5] Robertson J. et al. Nat Rev Rheumatol. 2013;9:513–23. [6] Perez-Baos S. et al. Br J Pharmacol. 2017;174:3018–31. Disclosure of Interests: None declared

Background Chondrocytes (CHs) in articular cartilage undergo phenotypic changes and senescence, restricting cartilage regeneration and favoring osteoarthritis (OA) progression. CHs and synovial cells from OA patients show a chronic increase in the channel protein connexin43 (Cx43), which regulates signal transduction. Extracellular vesicles (EVs), including exosomes, have been shown to play important roles in many biological functions and harbour Cx channels that allow the formation of gap junctions (GJs) between the exosome and the target cell, but the role of these EVs and exosomal-Cx43 in OA progression has not been studied yet. Objectives The objective of this study was to investigate the role of EVs released by OA chondrocytes (OACs) in cellular plasticity, inflammation and senescence of surrounding joint tissues. Methods CHs, bone and synovial cells were isolated from healthy and OA donors. EVs were obtained by ultracentrifugation and their protein content was analysed by LC-MS/MS. Protein levels were evaluated by western blot, immunofluorescence and flow cytometry. RNA expression was evaluated by RT-qPCR. Senescence and GJ intercellular communication was studied by flow cytometry and scrape loading assay, respectively. Results OACs showed increased levels of Cx43 within their EVs in comparison to the EVs isolated from healthy donors. Overexpression of Cx43 in CHs increased senescence and exosomal Cx43 levels. Interestingly, the treatment of CHs, bone cells and synoviocytes (target cells) with Cx43-EVs released by OACs, led to a significant increase in both Cx43 mRNA and protein levels in the recipient cells. The increase of Cx43 in target cells acted as a positive regulator of the reversion to a less differentiated state via EMT by activation of Twist-1, associated with increased levels of the mesenchymal markers, as CD105/CD166. The phenotypic changes detected in OACs lead to a decrease in Col2A1 and aggrecan expression in CHs, and increased the levels of cellular senescence and the senescence-associated secretory phenotype (SASP) in the target cells in target cells via p53/p16 and NF-ks. These results were corroborated by analysing the protein cargo of these Cx43 positive EVs by LC-MS/MS, finding enrichment in proteins related with catabolic, senescence and wound-healing pathways. Conclusion Our results indicate that Cx43-positive exosomes released by OACs may be involved in the spread of cellular senescence and inflammation involved in wound healing failure. Further understanding of the role of exosomal Cx43 in OA will help to halt the disease spread and progression. Disclosure of Interests None declared

Background Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage degradation, although both subchondral bone deterioration and synovial inflammation are also hallmarks of the disease. Chiropractic manipulation (CM) is a therapeutic approach focused on the diagnosis, treatment and prevention of musculoskeletal disorders. It is essentially manual, allowing the chiropractor to restore the normal range of motion and function of the joints, muscles, and ligaments. Clinical evidences suggest that CM might exert positive effects in OA patients. Objectives The aim of this study was to evaluate the effects of CM on cartilage, subchondral bone and synovitis state in an OA rabbit model. Methods Ten (4 months old) male New Zealand rabbits underwent knee surgery to induce OA by transection of anterior cruciate ligament. One week after the surgery, CM was performed using the chiropractic adjusting instrument ActivatorV as follows: Force 2 setting was applied onto the tibial tubercle of the right hind limb (true manipulation, TM-OA group), at an angle of approximately 90°, from medial to lateral, whereas the corresponding left hind limb received a false manipulation (FM-OA group) consisting of ActivatorV firing in the air and slightly touching the tibial tubercle. These procedures were repeated 3 times a week for 8 weeks. Three healthy animals were used as control. Following sacrifice, μCT and histological damage evaluation (Mankin score) were done in femur and tibiae. RANKL/OPG protein expressions were studied by immunohistochemistry in tibia samples. Sinovitis was assessed by Krenn score and immunohistochemistry for macrophages (RAM11) and angiogenesis (CD31) were done. Protein expression of VEGF, COX2, TNFa, IL-1b and MMP3 were determinated by Western Blot. Results In the OA rabbits, subchondral BMD decreased in relation to control, been partially reversed in the tibiae of TM-OA group. When subchondral trabecular bone structural parameters were analyzed by microCT, a significant decrease of bone volume/trabecular volume (BV/TV), trabecular number (Tb.N) and trabecular thickness (Tb.Th) was observed in the OA rabbits, while trabecular separation (Tb.S) increased compared to control animals. TM-OA group showed a significant improvement of these parameters compare to FM-OA group. FM-OA joints had higher Mankin score (cartilage damage) than control joints, and TM decreased Mankin score compare to FM-OA (p Conclusion These results suggest that mechanical stimulus induced by CM may retard the pathologic progression of OA. The beneficial effects of CM might be associated with an improvement in bone and cartilage damage and also inflammatory state. Disclosure of Interests None declared

Osteoarthritis (OA) is a chronic joint disease characterized by cartilage degradation, osteophyte formation, subchondral bone sclerosis, and synovitis. Systemic factors such as obesity and the components of the metabolic syndrome seem to contribute to its progression. Breakdown of cartilage ensues from an altered balance between mechanical overload and its absorption by this tissue. There is in this context a status of persistent local inflammation by means of the chronic activation of innate immunity. A broad variety of danger-associated molecular patterns inside OA joint are able to activate pattern recognition receptors, mainly TLR (toll-like receptor) 2 and 4, which are overexpressed in the OA cartilage. Chronic activation of innate immune responses in chondrocytes results in a robust production of pro-inflammatory cytokines and chemokines, as well as of tissue-destructive enzymes, downstream of NF-κB and MAPK (mitogen activated protein kinase) dependent pathways. Besides, the toxic effects of an excess of glucose and/or fatty acids, which share the same pro-inflammatory intracellular signalling pathways, may add fuel to the fire. Not only high concentrations of glucose can render cells prone to inflammation, but also AGEs (advanced glycation end products) are integrated into the TLR signalling network through their own innate immune receptors. Considering these mechanisms, we argue for the control of both primary inflammation and proteolytic catabolism as a preventive strategy in OA, instead of focusing treatment on the enhancement of anabolic responses. Even though this approach would not return to normal already degraded cartilage, it nonetheless might avoid damage extension to the surrounding tissue.

Background In order to gain insight into the early effects drawn by JAK inhibitors on intra-joint JAK/STAT-dependent signaling, we sought synovial activation of STATs and their end-products, along with their modification with tofacitinib (TOFA), at flare-up in antigen induced arthritis (AIA). New Zealand rabbits were randomly assigned to four groups –healthy controls, AIA, TOFA-treated AIA, or TOFA-treated controls–. AIA was induced with 4 weekly intra-articular ovalbumin injections in sensitized animals. TOFA (10 mg·kg− 1·day− 1) was administered for the last 2 weeks. Animals were euthanized 24 h after the last injection. Results AIA animals showed high-grade synovitis, which was partially improved by TOFA. No effects of the treatment were found on serum C-reactive protein or on the synovial macrophage infiltration at this stage. Synovial MMP-1,-3 and -13 expression levels in treated AIA rabbits were found to drop to those of controls, while a downregulation of IL6, IFNγ and TNF was evident in treated versus untreated AIA rabbits. Concurrently, a reduction in pSTAT1 and SOCS1, but not in pSTAT3, SOCS3 or active NFκB-p65, was noted with TOFA. Conclusions Studying the mechanism of action of immunomodulatory drugs represents a major challenge in vivo, since drug-dependent decreases in inflammation very likely mask direct effects on disease mechanisms. This study design allowed us to prevent any confounding effect resulting from reductions in the overall inflammatory status, hence assessing the true pharmacological actions of TOFA in a very severe synovitis. Our findings point to pSTAT1 and MMPs as early molecular readouts of response to this JAK inhibitor. Electronic supplementary material The online version of this article (10.1186/s12950-019-0206-2) contains supplementary material, which is available to authorized users.

Objectives Despite the high prevalence of osteoarthritis (OA) in postmenopausal women, a relationship between circulating estrogen levels and the development of OA has not been found. Therefore, the purpose of this study was to evaluate the expression and activity of aromatase, a key enzyme in local production of estrogens, in human OA cultured articular chondrocytes, and to determine the physiological relevance of this enzyme in cartilage. Methods Human OA articular chondrocytes were isolated and cultured. Local production of estradiol was measured after incubation with 100ng/ml testosterone for 8 and 24 h. Furthermore, chondrocytes were culture for 2 h, 48 h, 7 days or 15 days, or in alginate beads for 10 days. Aromatase, type II and X collagen, aggrecan, alkaline phosphatase, and Runx2 expression were evaluated in cartilage, freshly isolated chondrocytes and cultured chondrocytes. Results Aromatase was expressed and active in cultured human chondrocytes. Human cartilage, freshly isolated chondrocytes, and chondrocytes cultured for 2 h expressed an insignificant amount of aromatase; however, expression arose after 48 h of culture and remained increased thereafter. Aromatase expression was not related to estrogen deprivation and was inversely correlated with differentiation. Re-differentiation did not reduce its expression. Conclusions Aromatase presents an almost undetectable expression in human cartilage but is induced in cultured chondrocytes. Therefore, human cartilage might act as a mere target for estrogens rather than a producer, and researchers using cell expansion in culture for latter therapies should consider these changes in estrogen metabolism which may not be reverted after re-differentiation.

Background:The OMERACT Ultrasound (US) in calcium pyrophosphate deposition disease (CPPD) sub-task force has been working on the use of US in CPPD since 2014 first creating definitions for CPPD identification and then assessing the reliability[1].Objectives:Objective of this study is to assess the diagnostic accuracy (truth) of US in CPPD.Methods:Consecutive patients waiting to undergo knee replacement surgery due to osteoarthritis were enrolled in 12 centres from 6 countries. Each patient underwent US examination of the knee, focusing on the menisci and the hyaline cartilage, the day prior to surgery, scoring each site for presence/absence of CPP as defined previously[1]. After surgery, the menisci and the condyles were retrieved and examined microscopically. Six samples were collected, both from the surface and from the internal part of menisci and cartilage trying to cover a large part of it. All slides were observed under transmitted light microscopy and by compensated polarised microscopy. A dichotomous score was given for the presence/absence of CPP. US and microscopic analysis were performed by different operators, blind to each other’s findings. Sensitivity and specificity of US were calculated using microscopic findings as the gold standard.Results:101 patients have been enrolled in the study. 33 patients have been excluded due to loss of anatomical pieces at surgery. The mean age of the remaining 68 pts was 71yo (±8), 44 women, 34 were affected by CPPD according to microscopy. Overall and per site diagnostic US accuracy results are presented in table 1Diagnostic accuracySensitivitySpecificityPositive Predictive valueNegative Predictive valueGlobal0.750.910.590.690.87Medial meniscus0.820.870.770.770.87Lateral meniscus0.750.830.680.680.83Medial cartilage0.860.790.920.880.85Lateral cartilage0.820.710.880.770.84Medial side (combined cartilage and meniscus)0.820.880.760.790.87Lateral side (combined cartilage and meniscus)0.780.880.690.730.86Conclusion:Our results demonstrate that US is an accurate exam for identification of CPPD. The best combination of sensitivity and specificity is achieved by examining the medial aspect of the knee.References:[1]Filippou G, Scirè CA, Adinolfi A,et al.Identification of calcium pyrophosphate deposition disease (CPPD) by ultrasound: reliability of the OMERACT definitions in an extended set of joints—an international multiobserver study by the OMERACT Calcium Pyrophosphate Deposition Disease Ultrasound Subtask Force.Ann Rheum Dis2018;:annrheumdis-2017-212542. doi:10.1136/annrheumdis-2017-212542Disclosure of Interests:Georgios Filippou: None declared, Anna Scanu: None declared, Antonella Adinolfi: None declared, Carmela Toscano: None declared, Dario Gambera: None declared, Raquel Largo: None declared, Esperanza Naredo: None declared, Emilio Calvo: None declared, Gabriel Herrero-Beaumont: None declared, Pascal Zufferey: None declared, Christel Madelaine-Bonjour: None declared, Daryl MacCarter: None declared, Stanley Makman: None declared, Zachary Weber: None declared, Fabiana Figus: None declared, Ingrid Möller: None declared, Marwin Gutierrez: None declared, Carlos Pineda: None declared, Denise Clavijo Cornejo: None declared, Héctor García: None declared, Victor Ilizaliturri: None declared, Jaime Mendoza Torres: None declared, Raul Pichardo: None declared, Luis Carlos Rodriguez Delgado: None declared, Emilio Filippucci Speakers bureau: Dr. Filippucci reports personal fees from AbbVie, personal fees from Bristol-Myers Squibb, personal fees from Celgene, personal fees from Roche, personal fees from Union Chimique Belge Pharma, personal fees from Pfizer, outside the submitted work., Edoardo Cipolletta: None declared, Teodora Serban: None declared, Catalin Cirstoiu: None declared, Florentin Ananu Vreju: None declared, Dun Grecu: None declared, Gael Mouterde: None declared, Marcello Govoni: None declared, Leonardo Punzi: None declared, Nemanja Damjanov Grant/research support from: from AbbVie, Pfizer, and Roche, Consultant of: AbbVie, Gedeon Richter, Merck, Novartis, Pfizer, and Roche, Speakers bureau: AbbVie, Gedeon Richter, Merck, Novartis, Pfizer, and Roche, Lene Terslev Speakers bureau: LT declares speakers fees from Roche, MSD, BMS, Pfizer, AbbVie, Novartis, and Janssen., Carlo Alberto Scirè: None declared, Annamaria Iagnocco Grant/research support from: Abbvie, MSD and Alfasigma, Consultant of: AbbVie, Abiogen, Alfasigma, Biogen, BMS, Celgene, Eli-Lilly, Janssen, MSD, Novartis, Sanofi and Sanofi Genzyme, Speakers bureau: AbbVie, Alfasigma, BMS, Eli-Lilly, Janssen, MSD, Novartis, Sanofi

Background Osteoarthritis (OA) is a complex joint disease characterised by a progressive lost of articular cartilage (AC), synovial inflammation and subchondral bone alterations. The latest theories of OA pathogenesis implicate the interplay between mechanical damage and chronic inflammation that has been associated to the activation of the innate immune system, intricately involved in the development of this low-grade inflammation. During the course of OA, Toll like receptor (TLR) activation has been related to the release of cytokines and inflammatory mediators, which further aggravate synovitis and AC damage.1 In this scenario, hyaline chondrocytes seem to acquire a hypertrophic-like phenotype associated to AC degradation. 6-shogaol (6S), an effective anti-inflammatory Ginger derivative, is able to inhibit TLR4-mediated innate immune responses.2 Objectives Our aim was to study the therapeutic benefit of 6-shogaol studying its anti-inflammatory effects in an OA mice model, and in the modulation of hypertrophic markers in chondrocyte cultures. Methods C57BL/6 male mice were randomly assigned to two groups: control (n=7) and OA (n=17). OA was induced by transection of the medial menisco-tibial ligament. Nine OA mice started receiving 6S (15 mg/kg/day; OA +6S) since surgery. After 8 weeks, animals were euthanized and joints were collected. Chondrogenic differentiation was induced in vitro in the pre-chondrogenic cell line ATDC5 in presence or absence of 5 × 10–6M 6S. Gene expression of hypertrophic markers, as well as mineralization and proteoglycan synthesis were determined. Results Both synovial inflammation and AC damage were more severe in OA animals (Control: 0.1±0.1; OA: 3.0±0; p Conclusions Our results showed that 6S significantly prevented cartilage degradation and synovial inflammation, in parallel to a reduction in the presence of hypertrophic markers in the cartilage of OA mice. In vitro, 6S inhibited the chondrogenic differentiation of ATDC5 cells. These results suggest that 6S could work as a good treatment in OA both inhibiting differentiation markers and reducing the severity of joint damage in an OA murine model. References [1] Gomez R, et al. Nat Rev Rheumatol2015. [2] Villalvilla A, et al. J Mol Nutr Food Res2013. Disclosure of Interest P. Gratal: None declared, A. Lamuedra: None declared, A. Mediero Grant/research support from: CP15/00053 PI16/00991, G. Herrero-Beaumont Grant/research support from: PI16/00065, R. Largo Grant/research support from: PI15/00340

Background Osteoarthritis (OA) is a degenerative joint disease characterised by the degradation and inflammation of cartilage and synovium with bone damage. Different approaches that decrease subchondral bone remodelling during OA have demonstrated to improve cartilage damage and synovial inflammation. Chiropractic is a therapeutic approach focused on the diagnosis, treatment and prevention of musculoskeletal disorders. Chiropractic manipulation (CM) is essentially manual, allowing the chiropractor to restore the normal range of motion and function of the joints, muscles, and ligaments. We have previously observed that CM is able to increase subchondral bone mineral density (BMD) in an experimental model of osteoporosis1. Objectives To evaluate if CM could prevent the subchondral BMD alterations induced by OA, in association to an improvement in synovial membrane inflammation and cartilage damage in an OA model in rabbits. Methods Ten male New Zealand rabbits were submited knee surgery to induce OA by transection of anterior cruciate ligament. CM was performed using the chiropractic adjusting instrument ActivatorV 3 times a week during 8 weeks as follows: Force 2 setting was applied onto the tibial tubercle of the rabbit right hind limb (CM-OA group), at an angle of 90°, whereas the corresponding left hind limb received a false manipulation (FM-OA group) consisting of ActivatorV firing in the air and touching the tibial tubercle. Three healthy animals were used as controls. Following sacrifice, tibiae and femora were removed for mCT and histological evaluation. Synovial inflammation was evaluated by Krenn’s score and the protein presence of VEGF, MMP3 and CollagenVI in the synovial membrane was evaluated by western blot. Results In the OA rabbits, subchondral BMD decreased in relation to control animals (OA 4729±193 vs Control 5181±209 mg/cc), been partially reversed in the tibiae of OA rabbits with CM (TM-OA 5055±216 vs FM-OA 4404±170 mg/cc). Subchondral trabecular bone structural parameters were analysed by microCT and a significant decrease of bone volume/trabecular volume (BV/TV), trabecular number (TbN) and trabecular thickness (TbTh) was observed in the OA rabbits, while trabecular separation (TbS) increased compared to control animals. TM-OA group showed a significant improvement of these parameters compare to FM-OA group. TM-OA had lower cartilage damage compare to FM-OA (TM-OA 4±0,67 AU vs FM-OA 8±1,25 AU). TM-OA synovial membranes presented a total Krenn score lower than FM-OA joints (TM-OA 3±0,35 vs FM-OA 4.5±0,38 AU). OA synovial membranes showed higher levels of CollagenVI respect to control ones; TM-OA synovial membranes presented less expression of CollagenVI than FM-OA group (TM-OA 1.4±0,13 vs FM-OA 2.2±0,3 AU), been this associated with a decrease of both MMP3 (TM-OA 1.2±0,1 vs FM-OA 1.7±0.2 AU) and VEGF (TM-OA 1.2±0.14 vs FM-OA 1.9±0.26 AU). Conclusions These results support the hypothesis that CM may ameliorate subchondral BMD alterations induced by OA, in association to an improvement on synoviopathy and cartilage degradation. Reference [1] Lopez-Herradon A, et al. Impact of Chiropractic Manipulation on Bone and Skeletal Muscle of Ovariectomized Rats.CalcifTissueInt2017;101(5):519–529. Disclosure of Interest F. Conesa: None declared, R. Fujikawa: None declared, A. Mediero Grant/research support from: CP15/00053 PI16/00991, P. Gratal: None declared, F. Mulero: None declared, G. Herrero-Beaumont Grant/research support from: PI16/00065, R. Largo Grant/research support from: PI15/00340, A. Ortega-de Mues: None declared

Besides its primary function in locomotion, skeletal muscle (SKM), which represents up to half of human’s weight, also plays a fundamental homeostatic role. Through the secretion of soluble peptides, or myokines, SKM interacts with major organs involved in metabolic processes. In turn, metabolic cues from these organs are received by muscle cells, which adapt their response accordingly. This is done through an intricate intracellular signaling network characterized by the cross-talking between anabolic and catabolic pathways. A fine regulation of the network is required to protect the organism from an excessive energy expenditure. Systemic inflammation evokes a catabolic reaction in SKM known as sarcopenia. In turn this response comprises several mechanisms, which vary depending on the nature of the insult and its magnitude. In this regard, aging, chronic inflammatory systemic diseases, osteoarthritis and idiopathic inflammatory myopathies can lead to muscle loss. Interestingly, sarcopenia may persist despite remission of chronic inflammation, an issue which warrants further research. The Janus kinase/signal transducer and activator of transcription (JAK/STAT) system stands as a major participant in muscle loss during systemic inflammation, while it is also a well-recognized orchestrator of muscle cell turnover. Herein we summarize current knowledge about models of sarcopenia, their triggers and major mediators and their effect on both protein and cell growth yields. Also, the dual action of the JAK/STAT pathway in muscle mass changes is discussed. We highlight the need to unravel the precise contribution of this system to sarcopenia in order to design targeted therapeutic strategies.

Background Metabolic syndrome (MetS) may be associated with knee osteoarthritis (OA), but the association between the individual components and OA are not well-understood. We aimed to study the effect of hypercholesterolemia on synovial inflammation in knee OA. Methods OA was surgically induced in rabbits fed with standard diet (OA group, n = 10) or in rabbits fed with high fat diet (OA-HFD, n = 10). Healthy rabbits receiving standard diet (Control, n = 10) or fed with HFD (HFD, n = 6) were also monitored. Twelve weeks after OA induction, synovial membranes were isolated and processed for studies. Results Animals fed HFD showed higher levels of total serum cholesterol, triglycerides and C-reactive protein than control rabbits. Twelve weeks after OA induction, synovial membrane inflammation and macrophage infiltration were increased in rabbits with OA, particularly in the OA-HFD group. Extensive decrease of synovial adipose tissue area, adipocyte size and perilipin-1A synthesis were observed in the OA-HFD group in comparison to the OA and control groups. The HFD further increased the proinflammatory mediators IL-1β, IL-6 and TNF in the OA synovium. However, the synovial gene expression of adipokines, such as leptin and adiponectin, were markedly decreased in the rabbits with OA, especially in the OA-HFD group, in correlation with adipose tissue loss. However, circulating leptin was upregulated in the HFD and OA-HFD groups. Conclusion Our results indicate that a HFD is an aggravating factor worsening synovial membrane inflammation during OA, guided by increased infiltration of macrophages and removal of the adipose tissue, together with a remarkable presence of proinflammatory factors. Synovial adipocytes and dyslipemia could probably play pivotal roles in OA joint deterioration in patients with MetS, supporting that the link between obesity and OA transcends mechanical loading. Electronic supplementary material The online version of this article (doi:10.1186/s13075-017-1473-z) contains supplementary material, which is available to authorized users.

Osteoarthritis (OA), the most common rheumatic disease, is characterized by joint-space narrowing due to progressive cartilage degradation and alterations in subchondral bone and the synovial membrane. These articular disturbances can have severe consequences, including pain, disability and loss of joint architectural integrity. Although the aetiology of OA is not understood, chondrocyte-mediated inflammatory responses triggered by the activation of innate immune receptors by damage-associated molecules are thought to be involved. In this Review, we examine the relationship between Toll-like receptor 4 (TLR4) and OA in cartilage as well as in other OA-affected tissues, such as subchondral bone and synovium. We also discuss the different TLR4 agonists associated with OA and their effects in joint tissues. Finally, we describe existing and novel strategies that might be used to develop TLR4-specific disease-modifying OA drugs (DMOADs).

Background Patients with active rheumatoid arthritis (RA) have increased cardiovascular mortality, paradoxically associated with reduced serum lipid levels. In fact, an inverse relationship between C-reactive protein (CRP) and circulating lipid levels has been observed [1,2]. The Jak inhibitor tofacitinib ameliorates systemic and joint inflammation in RA with a concomitant increase in serum lipids [3]. Objectives Our aim was to analyze the effect of tofacitinib on the lipid and inflammatory profile of hyperlipidemic rabbits with chronic arthritis (CA), and on the regulation of reverse cholesterol transport (RCT) during chronic inflammation. Methods New Zealand male rabbits were randomly assigned to three groups: control group (n=6), chronic arthritic rabbits (CA, n=9) and CA rabbits receiving tofacitinib (CA+TOFA, n=9). All animals were fed ad libitum with a high-fat diet (0.5% cholesterol, 4% peanut oil). CA was induced in previously immunized rabbits by administering four intra-articular injections of ovalbumin. A group of rabbits received tofacitinib (10mg/kg/day) for two weeks. All animals were euthanized 6 weeks after challenge, when synovial and serum samples were collected. For in vitro studies, vehicle and ABCA1 siRNA-treated THP-1-derived macrophages were exposed to high lipid concentrations, and then stimulated with interferon gamma (IFNγ) in the presence or absence of tofacitinib, in order to assess their cholesterol efflux capacity and the involved mediators. Results CA rabbits showed lower levels of serum TC and LDL-C compared to controls (p=0.001, p=0.012), while TC/HDL-C ratio was higher in CA+TOFA rabbits when compared to CA animals (150±15 vs 231±17, p=0.004). Synovial inflammation and CRP levels were increased in CA animals, and a significant reduction was shown in CA+TOFA rabbits in both parameters. We also observed an inverse correlation between serum TC and CRP (R=-0.454, p=0.029). Tofacitinib was able to reduce the lipid content within synovial macrophages up to a 58% (p=0.041), although it did not modify synovial macrophage density. In foam macrophages in culture, an inflammatory milieu induced by IFNγ further stimulated the intracellular lipid accumulation (p=0.041) along with a decrease in the protein levels of the nuclear factor LXRα (liver X receptor α) and the cholesterol transporter ABCA1 (ATP-binding cassette transporter 1) (p=0.002 and p=0.0047, respectively). Tofacitinib prevented the lipid accumulation within macrophages (p=0.029) by increasing LXRα (p=0.047) and ABCA1 synthesis (p=0.004) in a Jak/STAT-dependent manner, while it was unable to reduce lipid accumulation in ABCA1 silenced macrophages. Conclusions Our results suggest that active inflammation could be associated with lipid accumulation within macrophages – in the synovium and probably in other tissues – thus inducing a decrease in serum lipid levels. Tofacitinib may prevent this phenomenon, at least partially, by increasing RCT pathways in macrophages. Taken together, these findings further explain how serum lipid levels are diminished in RA and partially justify the effect of tofacitinib on the lipid profile in RA patients. References Choy E, Sattar N. Ann Rheum Dis 2009;68:460–9. Johnsson H et al. Ann Rheum Dis 2013;73:1495–9. van Vollenhoven RF et al. N Engl J Med 2012;367:508–19. Disclosure of Interest None declared

Background HIV infection devastates the immune system but also affects other tissues and organs Bone alterations have been observed in HIV disease for nearly two decades, in particular a higher risk of low bone mineral density (BMD) and fragility fractures. Treatment with Tenofovir alone or as part of HAART, leads to changes in bone catabolism markers and significant reductions in BMD in children and young adults. Tenofovir is taken up by cells and phosphorylatedand inhibits HIV-reverse transcriptase by mimicking AMP. We have recently found that Tenofovir inhibits Pannexin-1/Connexin-43-mediated ATP release from cells and decreases extracellular adenosine levels and fibrosis in murine models. Inhibition of osteoclast formation via adenosine A2A receptor stimulation or increasing local adenosine concentration stimulates new bone formation as well as rhBMP-2. Objectives As adenosine and ATP are key regulators of bone homeostasis, we determined whether Tenofovir directly affects bone by an adenosine- or ATP-dependent mechanism and if treatment with Dipyridamole, an agent that increases extracellular adenosine by blocking cellular adenosine uptake, may be a useful treatment to counteract Tenofovir effects. Methods M-CSF/RANKL-induced osteoclast (OC) was studied in primary murine bone marrow culture as the number of TRAP-positive cells after challenge with Tenofovir (1nM-100μM) alone or in combination with Dipyridamole (1nM-100μM). OC markers were measured by RT-PCR. Pannexin-1 and Connexin-43 expression were permanently knocked down by lentiviral infection with appropriate shRNA or scrambled shRNA and these cells were induced to differentiate into OC by RANKL. Male C57Bl/6 mice received Tenofovir 75mg/Kg/day alone or in combination with Dipyridamole 1mg/Kg/day for 4 weeks. Double labelling of bone with calcein/Alizarin Red to analized bone formation was performed and long bones prepared for microCT and histology. Results Tenofovir produced a dose-dependent increase in OC differentiation (EC50=44.5nM) that was reversed by Dipyridamole (IC50=0.3μM). When Pannexin-1 and Connexin-43 were absent, Tenofovir did not increase OC number. Tenofovir increases Cathepsin K and NFATc1 mRNA levels during OC differentiation, and the effect was reverted by Dipyridamole. Tenofovir reduced bone formation in vivo (19±2μm bone aposition vs 35±4μ m untreated p Conclusions These results indicate that Tenofovir enhances OC differentiation and inhibits osteoblast differentiation by an adenosine-dependent mechanism and suggests that treatment with agents that increase local adenosine concentrations, like Dipyridamole, might prevent bone loss following Tenofovir treatment. Disclosure of Interest F. Conesa: None declared, P. Llamas: None declared, T. Wilder: None declared, P. Atencio: None declared, A. Cabello: None declared, M. Gόrgolas: None declared, B. Cronstein: None declared, R. Largo: None declared, G. Herrero-Beaumont: None declared, A. Mediero Grant/research support from: Instituto de Salud Carlos III, Fondos FEDER

Stromal cell-derived factor 1 (SDF-1) is a potent chemoattractant cytokine with various biological functions such as stem cell mobilization, inflammatory cell infiltration and angiogenesis. Therefore, it has also been implicated in several pathological processes, from ischemic conditions to cancer. Remarkably, SDF-1 and its receptors, CXCR4 and CXCR7, are also present in joint tissues, where they play a role in the pathogenesis of rheumatoid arthritis (RA) and osteoarthritis (OA).This review summarizes the physiological and pathological role of SDF-1 signaling and its involvement in RA and OA. That includes synovial inflammation, bone erosion, cartilage degradation and increased bone turnover. Although this cytokine could play different roles in these rheumatic diseases, specific and differentiated therapeutic targets in each process can be identified. Current therapeutic strategies to block SDF-1 signaling in several diseases and their possible use in rheumatic diseases are also discussed.Emerging drugs that block CXCR4 or CXCR7 in different disorders may represent promising therapies for rheumatic disease via inhibition of key pathological events involved in the progression of RA and OA.

Background Osteoarthritis (OA) joints display relevant microstructure alterations associated to an increase in remodeling at subchondral bone, which supports its crucial role in OA pathogenesis. Despite this, the treatment of knee OA patients with antiresorptive drugs has given discordant results, suggesting the existence of a particular patient subset with good response to halting high subchondral remodeling. Objective To identify an OA phenotype that may obtain major benefit from therapy with bone-acting agents. Methods A systematic review of the literature was performed by searching the Medline and PubMed databases from 1990 to April 2013 using the following keywords: subchondral bone, articular cartilage, and osteoarthritis in various combinations with bone agents, bone mineral density, and scintigraphy. Results Early animal and human studies provided the rationale for the beneficial use of bone agents on OA cartilage damage. Several bone-acting agents have reduced low back pain and likely spondylosis progression. Recently, strontium ranelate has been reported to exert both structural and clinical benefits in knee OA patients with radiological progression. However, other antiresorptives have shown divergent results. Human studies suggest that these contradictory results may be due to the lack of well-defined OA phenotypes and an accurate methodology to recruit and follow up these patients. Conclusions A particular subset of postmenopausal patients with high remodeling and/or low subchondral bone density may benefit from the treatment with bone-acting agents hindering OA progression. This OA population could be identified with the simultaneous use of subchondral bone dual-energy X-ray absorptiometry and scintigraphy.

cope Ginger has long been used in traditional Asian medicine to treat osteoarthritis. Indeed, scientific research has reported that ginger derivatives (GDs) have the potential to control innate immune responses. Given the widespread use and demonstrated properties of GDs, we set out to study their anti-inflammatory and anticatabolic properties in chondrocytes. Methods and results 6-shogaol (6-S), the most active GD, was obtained from ginger. 6-S was not toxic as measured by MTT assay, and inhibited NO production and IL-6 and MCP-1 induced gene expression in LPSbut not in IL-1β-stimulated chondrocytes. 6-S also inhibited LPS-mediated ERK1/2 activation as well as NOS2 and MyD88 induced expression as determined by Western blot. Moreover, zymography revealed that 6-S inhibited matrix metalloproteinases (MMP) 2/9 induction in LPS-treated cells. Hydrated 6-S was modified to obtain a compound (SSi6) without 6-S potential anti-inflammatory properties. Both 6-S and SSi6 inhibited cathepsin-K activity. Conclusion 6-S blocked TLR4-mediated innate immune responses and MMP induction in chondrocytes. These results, together with GDs-mediated cathepsin-K inhibition, suggest the potential for GDs use against cartilage and bone degradation. Therefore, considering that clinical trials involving oral administration of ginger achieved relevant nontoxic GDs serum concentrations, we suggest that a ginger-supplemented diet might reduce OA symptoms.

Osteoarthritis is the most common chronic joint disorder especially during aging. Although with controversies, glucosamine, both in its forms of sulfate and hydrochloride, and chondroitin sulfate are commonly employed to treat osteoarthritis. Due to the modest improve in the symptoms observed in patients treated with these drugs alone, a formulation combining both agents has been considered. The discrepant results achieved for pain control or structural improvement in osteoarthritis patients has been attributed to the quality of chemical formulations or different bias in clinical studies. The current study has been designed to test the effects of two different combined formulations with adequate pharmaceutical grade of these drugs in osteoarthritic joints, and to explore the underlying mechanisms modulated by both formulations in different osteoarthritis target tissues. Knee osteoarthritis was surgically induced in experimental rabbits. Some animals received the combined therapy (CT)1, (chondroitin sulfate 1200mg/day + glucosamine sulfate 1500mg/day), or the CT2 ((chondroitin sulfate 1200mg/day + glucosamine hydrochloride 1500mg/day). Neither CT1 nor CT2 significantly modified the cartilage damage or the synovial inflammation observed in osteoarthritic animals. Treatments were also unable to modify the presence of pro-inflammatory mediators, and the synthesis of metalloproteinases in the cartilage or in the synovium of osteoarthritic animals. Combined therapies did not modify the decrease in the subchondral bone mineral density observed in osteoarthritic rabbits. Therapies of chondroitin sulfate plus glucosamine sulfate or chondroitin sulfate plus glucosamine hydrochloride failed to improve structural damage or to ameliorate the inflammatory profile of joint tissues during experimental osteoarthritis.

The lack of a complete understanding of the complex processes involved in the etiopathogenesis and subsequent appropriate phenotyping makes it difficult to find therapies that may be efficacious in most patients with osteoarthritis (OA). Consensus recommendations involve mainly non-pharmacological approaches. Analgesics and NSAIDs are considered second choice options due to their poor efficacy/safety ratios. To some extent, OA may be considered an orphan disease. Therefore, there is an urgent need to identify effective and safe new pharmacologic modalities for treating OA.This review is based on a Medline comprehensive literature search for published articles evaluating new formulations of current drugs and promising emerging therapies in OA. We discuss the current status of novel systemic agents in development including potent analgesic options, inhibitors of innate immunity, inducible nitric oxide synthase (iNOS), pro-inflammatory cytokines and cartilage proteases as well as bone agents. Furthermore, we also revise the potential benefit of intraarticular (IA) therapy with hyaluronic acid (HA), pro-inflammatory mediator blockers, cartilage anabolic agents, mesenchymal stem cell and gene transfer.Despite the renewed interest in the search of new compounds for treatment of OA, results have been limited. Novel systemic and IA administered agents are in active development. IA drug administration is particularly an attractive approach because can diminish some of the severe side effects associated with systemic drugs. Indeed, one of the most promising fields for pharmacology innovation in OA is joint injected therapy, as suggested by preliminary data from recent studies using IA sprifermin (rhFGF-18), mesenchymal stem cells or TGF-B1 transduced allogenic chondrocytes. Last, the effort to develop new drugs must be accompanied by the interest for establishing well-defined phenotypes, and only then, a more tailored therapy should be practiced in OA.

Objective To assess the efficacy and safety of combination therapy with chondroitin sulfate (CS) and glucosamine sulfate (GS) compared to placebo in patients with symptomatic knee osteoarthritis (OA). Methods A multicenter, randomized, double-blind, placebo-controlled study was performed in 164 patients with Kellgren/Lawrence grade 2 or grade 3 radiographic knee OA and moderate-to-severe knee pain (mean ± SD global pain score 62.1 ± 11.3 mm on a 100-mm visual analog scale [VAS]). Patients were randomized to receive either combined treatment with CS (1,200 mg) plus GS (1,500 mg) or placebo in a single oral daily dose for 6 months. The mean change from baseline in the VAS global pain score was set as the primary end point. Secondary outcomes included the mean change in the investigator's global assessment of disease activity, total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), pain and function subscale scores on the WOMAC, responder rates based on the Outcome Measures in Rheumatology (OMERACT)–Osteoarthritis Research Society International (OARSI) 2004 response criteria, and rescue medication use. Adverse events were also recorded. A Data and Safety Monitoring Board was instituted to ensure patient safety and data accuracy. Results Intriguingly, in the modified intent-to-treat (mITT) population, CS/GS combination therapy was inferior to placebo in the reduction of joint pain (mean ± SD change in VAS global pain score over 6 months −11.8 ± 2.4 mm [19% reduction] in patients receiving CS plus GS versus −20.5 ± 2.4 mm [33% reduction] in patients receiving placebo; peak between-group difference in global pain score at 6 months 8.7 mm [14.2%], P

Osteoarthritis (OA), the most common form of arthritis, is a debilitating and progressive disease that has become a major cause of disability and impaired quality of life in the elderly. OA is considered an organ disease that affects the whole joint, where the subchondral bone (SB) plays a crucial role. Regardless of whether SB alterations precede cartilage damage or appear during the evolution of the disease, SB is currently recognised as a key target in OA treatment. In fact, bone abnormalities, especially increased bone turnover, have been detected in the early evolution of some forms of OA. Systemic osteoporosis (OP) and OA share a paradoxical relationship in which both high and low bone mass conditions may result in induction and/or OA progression. Recent findings suggest that some drugs may be useful in treating both processes simultaneously, at least in a subgroup of patients with OA and OP. This review focuses on the role of SB in OA pathogenesis, describing relevant underlying mechanisms involved in the process and examining the potential activity as disease-modifying anti-osteoarthritic drugs (DMOADs) of certain SB-targeting agents currently under study.

The newly published findings from the Chondroitin Versus Celecoxib Versus Placebo Trial (CONCEPT) underscore the complexity of performing clinical trials in the field of knee osteoarthritis. But do the results of CONCEPT merit the consideration of chondroitin sulfate as a first-line therapy?

The pharmacological treatment of osteoarthritis is traditionally accomplished with nonspecific symptomatic agents that are generally effective only for acute symptom relief. Compounds are currently being searched for that might exert specific effects on osteoarthritis pathogenesis and thus induce at least a similar shortterm symptomatic effect, but also control the progression of the disease in the long-term. Glucosamine sulfate is, so far, the only drug that has demonstrated a combined symptom-modifying and potential structure-modifying effect in knee osteoarthritis when used as the prescription crystalline glucosamine sulfate formulation at the dose of 1500 mg once daily. These effects may be explained by reversal of the proinflammatory and joint-degenerating effects of IL-1 through the inhibition of the cytokine intracellular signaling pathway. However, efficacy data obtained with this prescription glucosamine sulfate formulation may not be applicable to all glucosamine products available as generics or dietary supplements, owing to pharmacodynamic and pharmacokinetic reasons.

BACKGROUND AND PURPOSE Non-steroidal anti-inflammatory drugs improve inflammatory cachexia in several conditions. Thus, we have explored inhibition of cyclooxygenase-2 (COX-2) in an experimental model of rheumatoid cachexia in rabbits. EXPERIMENTAL APPROACH Chronic arthritis was induced in immunized rabbits by repeated intra-articular injections of ovalbumin. To increase the degree of systemic inflammation and also to induce atherosclerotic lesions, the animals were fed a hyperlipidaemic diet (2% cholesterol and 6% peanut oil) and were given an endothelial injury of the femoral artery. Rabbits were randomized to receive the COX-2 inhibitor celecoxib (10 mg·kg−1·day−1) or no treatment. After 4 weeks, sera, peripheral mononuclear cells and vessel specimens were collected. KEY RESULTS Inhibition of COX-2 by celecoxib modulated the systemic inflammatory response and increased total cholesterol and triglyceride levels. Celecoxib also minimized weight loss and prevented serum albumin fall. At a vascular level, celecoxib reduced COX-2 protein in the femoral arterial wall, but did not modify size or the macrophage infiltration of femoral lesions nor the percentage of rabbits with spontaneous aortic plaques. CONCLUSIONS AND IMPLICATIONS Our animal model induced a severe inflammatory cachexia, comparable to that of persistently active rheumatoid arthritis. The inhibition of COX-2 by celecoxib improves this state, suggesting that COX products play an important role in its development, without affecting the development or the progression of vascular lesions. Overall, these results suggest that celecoxib might be considered as a new therapeutic tool for the treatment of rheumatoid cachexia.

Summary Objective Our aim was to explore the effect of chondroitin sulfate (CS), a natural glycosaminoglycan with attributed anti-inflammatory properties, on synovitis in a rabbit model of chronic arthritis with intense systemic inflammation bolstered by endothelial lesion and atherosclerotic diet. Methods Chronic arthritis was induced by intraarticular injections of ovalbumin in immunized rabbits. Systemic inflammation was boosted in these rabbits by receiving a hyperlipidemic diet after producing an endothelial lesion in the femoral arteries. A group of these rabbits were treated with CS (100mg/kg/day). At sacrifice, synovial membranes were isolated, and cyclooxygenase-2 (COX-2) and chemokine (C-C motif) ligand 2 (CCL2) mRNA, as well as protein expression were assayed by quantitative real-time polymerase chain reaction (RT-PCR) and western blot studies. Histological synovial examination was also carried out employing the histopathological synovitis score (Krenn scale). Results CS diminished both gene expression and protein synthesis of COX-2 and CCL2, and the histopathological score of the synovial membrane, when compared to untreated rabbits. In fact, CS partially prevented the intimal layer proliferation and the inflammatory cell infiltration in the synovial membrane, which was observed in non-treated animals. Conclusion CS reduced the inflammatory response of the synovial membrane, as well as decreased the synovial histopathological lesions in our animal model. Further studies are warranted to demonstrate whether CS might be beneficial in the treatment of inflammatory arthritis.

SummaryThe rheumatic diseases have been associated with accelerated atherosclerosis. Rheumatoid arthritis (RA) is a systemic inflammatory disease characterized by persistent synovial inflammation which leads to disability and structural changes in joints. Epidemiological studies have demonstrated an increased cardiovascular mortality in patients with RA. In these patients, atherosclerotic plaque occurs earlier, and it has a faster evolution than in general population. Atherosclerosis (AT) is also an inflammatory disease partly mediated by cytokines, many of them involved on chronic synovitis. Our group has developed a rabbit experimental model of AT aggravated by chronic arthritis to study inflammatory mechanisms involved on the progression of vascular lesions and their response to drugs. A preliminary study using this model suggests a beneficial effect of chondroitin sulphate (CS), a drug recommended for the treatment of osteoarthritis, in controlling AT lesions. Yet clinical trials should be conducted with this compound to address the same hypothesis in human studies.

The purpose of this study was to compare the effects of estrogen deficiency and bone mass loss on normal knee cartilage in mature rabbits. Bilateral ovariectomy (OVX) was performed in 13 rabbits, 6 of which also received systemic glucocorticoid for 4 weeks. Seven additional healthy rabbits were used as controls. Bone mineral density (BMD) was measured by dual X-ray absorptiometry in lumbar spine, knee, and subchondral bone of the knee at baseline and 22 weeks after OVX. After sacrifice, the knees were dissected, macroscopy was assessed, and histological cartilage abnormalities were evaluated according to the Mankin score. Correlations of Mankin with BMD at different regions were also performed. When compared to baseline, differences in BMD were only found in spine and knee of the animals receiving glucocorticoids. All the animals subjected to OVX had a significantly higher Mankin score than controls. Mankin was upper in OVX animals receiving glucocorticoids, but differences were not significant. The Mankin score was inversely related with BMD in lumbar spine (r = -0.67; p < 0.01). Although low bone mineral density contributes to the minor osteoarthritic alterations observed in our model, estrogen deficiency itself seems to act directly to induce the main pathogenic effects in healthy cartilage of the rabbit.

Summary Objective To simultaneously study the effect of a selective cyclooxygenase-2 (COX-2) inhibitor and that of a classic non-steroidal anti-inflammatory drug (NSAID) on the expression of pro-inflammatory genes in the cartilage of patients with severe knee osteoarthritis (OA) and in cultured human OA chondrocytes. Methods A 3-month clinical trial was carried out on 30 patients with severe knee OA scheduled for knee replacement surgery. Patients were randomized into two groups: patients treated with celecoxib (CBX) and patients treated with aceclofenac (ACF). OA patients who did not want to be treated served as the control group. After surgery, cartilage was processed for molecular biology studies. We also employed cultured chondrocytes from different OA patients to examine NSAID effects on pro-inflammatory gene expression in cells stimulated with interleukin (IL)-1β. Results Both CBX and ACF inhibited COX-2, microsomal prostaglandin E synthase-1 (mPGES-1) and inducible nitric oxide synthase (iNOS) synthesis in the articular cartilage of OA patients. In cultured chondrocytes, both NSAID decreased COX-2 and mPGES-1 synthesis and prostaglandin E2 (PGE2) release induced by IL-1β, while no effect was observed on nitric oxide or iNOS synthesis. In OA patients, only CBX decreased tumor necrosis factor alpha and IL-1β expression in the cartilage, while both NSAID diminished IL-1β induced cytokine synthesis in cultured OA chondrocytes. Conclusions Both NSAID diminished PGE2 release and induced a decrease in COX-2 and mPGES-1 synthesis in the cartilage from OA patients and in OA chondrocytes. These data suggest that prolonged therapy with PGE2 blocking agents decreases PGE2 production not only by direct inhibition of COX-2 activity, but also by down-regulating COX-2 and mPGES-1 synthesis in the cartilage. However, CBX and ACF seem to have a different anti-inflammatory profile in controlling pro-inflammatory gene expression in the cartilage.

Background and purpose: Among the agents employed to manage osteoarthritis, chondroitin sulphate (CS) is a natural glycosaminoglycan with an anti-inflammatory effect on joint cells. CS might also influence the inflammatory component of atherosclerosis. Our aim was to examine the effect of CS administration on vascular injury and on markers of systemic inflammation in a rabbit model of atherosclerosis aggravated by systemic inflammation provoked by chronic antigen-induced arthritis. Experimental approach: Atherosclerosis was induced in rabbits by maintaining them on a hyperlipidaemic diet after producing an endothelial lesion in the femoral arteries. Simultaneously, chronic arthritis was induced in these animals by repeated intraarticular injections of ovalbumin in previously immunized rabbits. A group of these rabbits were treated prophylactically with CS (100 mg kg−1day−1) and when the animals were killed, serum and peripheral blood mononuclear cells (PBMC) were isolated. Furthermore, femoral arteries and thoracic aorta were used for gene expression studies and histological examination. Key results: CS administration reduced the concentration of the proinflammatory molecules C-reactive protein and IL-6 in serum. Likewise, CS inhibited the expression of CCL2/monocyte chemoattractant protein (MCP)-1 and cyclooxygenase (COX)-2 in PBMC, and reduced the nuclear translocation of nuclear factor-κB. In the femoral lesion, CS also diminished the expression of CCL2 and COX-2, as well as the ratio of the intima/media thickness. Moreover, CS decreased the percentage of rabbits with atherosclerosis and chronic arthritis that developed vascular lesions in the aorta. Conclusions and implications: These findings suggest that CS treatment may to some extent impede the progression of atherosclerosis. British Journal of Pharmacology (2008) 154, 843–851; doi:10.1038/bjp.2008.113; published online 21 April 2008