Permeability of rheumatoid and normal human synovium to specific plasma proteins

Evaluation of the prognostic nutritional index (PNI) as a tool for assessing disease activity in rheumatoid arthritis patients

OBJECTIVES

Rheumatoid arthritis (RA) is an autoimmune disease of unknown exact cause, characterized by chronic inflammation. The prognostic nutritional index (PNI), reflecting albumin concentration and lymphocyte count, is a newly established inflammation-based nutritional score. This study aimed to determine the relationship between PNI and disease activity in RA patients.

PATIENTS AND METHODS

This cross-sectional study included 138 RA patients who met the 2010 revised criteria of the American College of Rheumatology (ACR) for RA. PNI was calculated using the following formula: 10 × serum albumin value (g/dL) + 0.005 × total lymphocyte count in the peripheral blood (per mm3). The study population was divided into two groups: DAS28-ESR ≤ 3.2 (group 1 with remission and low disease activity) and DAS28-ESR > 3.2 (group 2 with moderate and high disease activity).

RESULTS

A total of 138 patients with a mean age of 52.1 years were recruited. While the female gender was more prevalent in both groups, it was significantly higher in group 2 (p < 0.05). Group 2 exhibited a lower PNI compared to those in group 1 (42.17 ± 3.46 vs. 44.02 ± 2.92; p = 0.001). Multivariate logistic regression analyses revealed that PNI was an independent predictor of disease activity (OR, 0.850; 95% CI, 0.735-0.983; p = 0.029). ROC curve analysis determined that the optimal cutoff value of PNI for disease activity was 43.01, with a sensitivity of 69.1% and specificity of 57.7% (AUC, 0.66; 95% CI, 0.57-0.75, p = 0.001).

CONCLUSION

This study demonstrates that the simple and readily available PNI could serve as an independent predictor of disease activity in rheumatoid arthritis patients. Key Points •The relationship between disease activity and the prognostic nutritional index, which is a nutritional indicator, in rheumatoid arthritis patients was investigated. •It has been shown that there is a connection between low PNI and high disease activity. •It has been shown that PNI can be used to evaluate disease severity with a simple calculation.

Reproducible Synthesis of Biocompatible Albumin Nanoparticles Designed for Intra-articular Administration of Celecoxib to Treat Osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis, with intra-articular (IA) delivery of therapeutics being the current best option to treat pain and inflammation. However, IA delivery is challenging due to the rapid clearance of therapeutics from the joint and the need for repeated injections. Thus, there is a need for long-acting delivery systems that increase the drug retention time in joints with the capacity to penetrate OA cartilage. As pharmaceutical utility also demands that this is achieved using biocompatible materials that provide colloidal stability, our aim was to develop a nanoparticle (NP) delivery system loaded with the COX-2 inhibitor celecoxib that can meet these criteria. We devised a reproducible and economical method to synthesize the colloidally stable albumin NPs loaded with celecoxib without the use of any of the following conditions: high temperatures at which albumin denaturation occurs, polymer coatings, oils, Class 1/2 solvents, and chemical protein cross-linkers. The spherical NP suspensions were biocompatible, monodisperse with average diameters of 72 nm (ideal for OA cartilage penetration), and they were stable over 6 months at 4 °C. Moreover, the NPs loaded celecoxib at higher levels than those required for the therapeutic response in arthritic joints. For these reasons, they are the first of their kind. Labeled NPs were internalized by primary human articular chondrocytes cultured from the knee joints of OA patients. The NPs reduced the concentration of inflammatory mediator prostaglandin E2 released by the primaries, an indication of retained bioactivity following NP synthesis. Similar results were observed in lipopolysaccharide-stimulated human THP-1 monocytes. The IA administration of these NPs is expected to avoid side-effects associated with oral administration of celecoxib and to maintain a high local concentration in the knee joint over a sustained period. They are now ready for evaluation by IA administration in animal models of OA.

Prodrug-based nanomedicines for rheumatoid arthritis

Most antirheumatic drugs with high toxicity exhibit a narrow therapeutic window due to their nonspecific distribution in the body, leading to undesirable side effects and reduced patient compliance. To in response to these challenges, prodrug-based nanoparticulate drug delivery systems (PNDDS), which combines prodrug strategy and nanotechnology into a single system, resulting their many advantages, including stability for prodrug structure, the higher drug loading capacity of the system, improving the target activity and bioavailability, and reducing their untoward effects. PNDDS have gained attention as a method for relieving arthralgia syndrome of rheumatoid arthritis in recent years. This article systematically reviews prodrug-based nanocarriers for rheumatism treatment, including Nano systems based on prodrug-encapsulated nanomedicines and conjugate-based nanomedicines. It provides a new direction for the clinical treatment of rheumatoid arthritis.

Use of Stem Cells for the Treatment of Musculoskeletal Injuries in Horses

Mesenchymal stem cells (MSCs) are used as a regenerative therapy in horses for musculoskeletal injury since the late 1990s and in some regions are standard of care for certain injuries. Yet, there is no Food and Drug Administration-approved MSC therapeutic in the United States for horses. In humans, lack of regulatory approval in the United States has been caused by failure of late-phase clinical trials to demonstrate consistent efficacy, perhaps because of nonuniformity of MSC preparation and application techniques. This article discusses clinical evidence for musculoskeletal applications of MSCs in the horse and current challenges to marketing approval.

The potential role of synovial cells in the progression and treatment of osteoarthritis

Osteoarthritis (OA), the commonest arthritis, is characterized by the progressive destruction of cartilage, leading to disability. The Current early clinical treatment strategy for OA often centers on anti-inflammatory or analgesia medication, weight loss, improved muscular function and articular cartilage repair. Although these treatments can relieve symptoms, OA tends to be progressive, and most patients require arthroplasty at the terminal stages of OA. Recent studies have shown a close correlation between joint pain, inflammation, cartilage destruction and synovial cells. Consequently, understanding the potential mechanisms associated with the action of synovial cells in OA could be beneficial for the clinical management of OA. Therefore, this review comprehensively describes the biological functions of synovial cells, the synovium, together with the pathological changes of synovial cells in OA, and the interaction between the cartilage and synovium, which is lacking in the present literature. Additionally, therapeutic approaches based on synovial cells for OA treatment are further discussed from a clinical perspective, highlighting a new direction in the treatment of OA.

Efficacy and safety of anti-TNF multivalent NANOBODY® compound 'ozoralizumab' without methotrexate co-administration in patients with active rheumatoid arthritis: A 52-week result of phase III, randomised, open-label trial (NATSUZORA trial)

OBJECTIVES

The aim is to assess the efficacy and safety of a 52-week subcutaneous ozoralizumab treatment at 30 and 80 mg without methotrexate (MTX) in active rheumatoid arthritis.

METHODS

This randomised, open-label, multicentre phase III trial randomly allocated 140 patients in 2:1 ratio as subcutaneous ozoralizumab at 30 or 80 mg every 4 weeks for 52 weeks without MTX.

RESULTS

Both groups administered ozoralizumab at 30 and 80 mg showed good clinical improvement. The American College of Rheumatology response rates were high at Week 24 and maintained through 52 weeks. The ozoralizumab groups also showed good improvement in other end points, and improvements observed from Week 1 were maintained through 52 weeks. Improvements in many efficacy assessments were similar between doses. No deaths were reported, and serious adverse events occurred in a total of 20 patients in the ozoralizumab groups. Increased antidrug antibodies were observed in approximately 40% of patients in the ozoralizumab groups, and 27.7% of the patients in the 30 mg group were neutralising antibody-positive.

CONCLUSIONS

Ozoralizumab, at 30 and 80 mg, demonstrated significant therapeutic effects without MTX, and the efficacy was maintained for 52 weeks with active rheumatoid arthritis. Ozoralizumab showed an acceptable tolerability profile over 52 weeks.

Efficacy and safety of the anti-TNF multivalent NANOBODY® compound ozoralizumab in patients with rheumatoid arthritis and an inadequate response to methotrexate: A 52-week result of a Phase II/III study (OHZORA trial)

OBJECTIVE

To assess the efficacy and safety through a 52-week treatment with subcutaneous ozoralizumab at 30 or 80 mg in patients with active rheumatoid arthritis despite methotrexate therapy.

METHODS

This multicentre, randomized, placebo-controlled, double-blind, parallel-group confirmatory trial included a 24-week double-blind treatment period followed by a 28-week open-label treatment period. The double-blind treatment period randomized 381 (2:2:1) patients to placebo and ozoralizumab at 30 or 80 mg, and patients receiving placebo were re-randomized (1:1) to ozoralizumab at 30 or 80 mg in the open-label period.

RESULTS

The ozoralizumab groups showed good clinical improvement, with high American College of Rheumatology response rates at 52 weeks, as well as good improvements in other endpoints, which were observed from Day 3 and maintained through Week 52. Furthermore, the ozoralizumab groups showed a high remission rate in clinical and functional remission at Week 52. Serious adverse events occurred in a total of 23 patients in the ozoralizumab groups, without differences in incidence between doses.

CONCLUSIONS

Ozoralizumab demonstrated significant therapeutic effects and efficacy, which was maintained for 52 weeks. The safety profile was consistent with the evaluated results in interim analysis at Week 24, and ozoralizumab was well-tolerated up to Week 52.

Multifunctional Janus Nanoplatform for Efficiently Synergistic Theranostics of Rheumatoid Arthritis

Progress has been made in the application of nanomedicine in rheumatoid arthritis (RA) treatment. However, the whole process of monitoring and treatment of RA remains a formidable challenge due to the complexity of the chronic autoimmune disease. In this study, we develop a Janus nanoplatform (denoted as Janus-CPS) composed of CeO₂-Pt nanozyme subunit on one side and periodic mesoporous organosilica (PMO) subunit on another side for simultaneous early diagnosis and synergistic therapy of RA. The Janus nanostructure, which enables more active sites to be exposed, enhances the reactive oxygen species scavenging capability of CeO₂-Pt nanozyme subunit as compared to their core-shell counterpart. Furthermore, micheliolide (MCL), an extracted compound from natural plants with anti-osteoclastogenesis effects, is loaded into the mesopores of PMO subunit to synergize with the anti-inflammation effect of nanozymes for efficient RA treatment, which has been demonstrated by in vitro cellular experiments and in vivo collagen-induced arthritis (CIA) model. In addition, by taking advantage of the second near-infrared window (NIR-II) fluorescent imaging, indocyanine green (ICG)-loaded Janus-CPS exhibits desirable effectiveness in detecting RA lesions at a very early stage. It is anticipated that such a Janus nanoplatform may offer an alternative strategy of functional integration for versatile theranostics.

A composite device for viscosupplementation treatment resistant to degradation by reactive oxygen species and hyaluronidase

Osteoarthritis (OA) is one of the most common musculoskeletal disorders in the world. OA is often associated with the loss of viscoelastic and tribological properties of synovial fluid (SF) due to degradation of hyaluronic acid (HA) by reactive oxygen species (ROS) and hyaluronidases. Viscosupplementation is one of the ways how to effectively restore SF functions. However, current viscosupplementation products provide only temporal therapeutic effect because of short biological half-life. In this article we describe a novel device for viscosupplementation (NV) based on the cross-linked tyramine derivative of HA, chondroitin sulfate (CS), and high molecular weight HA by online determination of viscoelastic properties loss during degradation by ROS and hyaluronidase. Rheological and tribological properties of developed viscosupplement were compared with HA solutions with different molecular weights in the range 500-2000 kDa, which are currently commonly used as medical devices for viscosupplementation treatment. Moreover, based on clinical practice and scientific literature all samples were also diluted by model OA SF in the ratio 1:1 (vol/vol) to better predict final properties after injection to the joint. The observed results confirmed that NV exhibits appropriate rheological properties (viscosity, elastic, and viscous moduli) comparable with healthy SF and maintain them during degradation for a significantly longer time than HA solutions with molecular weight in the range 500-2000 kDa and cross-linked material without CS.

Low serum albumin concentration is associated with increased risk of osteoporosis in postmenopausal patients with rheumatoid arthritis

BACKGROUND

The risk of osteoporosis in patients with rheumatoid arthritis (RA) is frequently overlooked, and investigating a simple indicator in routine care may be beneficial to motivate osteoporosis examination. The aim of this retrospective, case-controlled study was to identify the correlation between serum albumin concentrations and the prevalence of osteoporosis in postmenopausal patients with RA.

METHODS

This study enrolled 197 patients who underwent dual-energy X-ray absorptiometry of lumbar spine (LS) and proximal femur without osteoporosis treatment [mean age, 67.5 years; disease duration, 12.8 years; Disease Activity Score assessing 28 joints with C-reactive protein, 2.0; prednisolone dose, 4.9 mg/day (usage, 42.6%); and LS T-score, -1.9]. Patients were classified into 2 groups: osteoporosis, defined as ≥ 1 part bone mineral density T-score ≤ -2.5 or history of fragility fracture of the vertebra or proximal femur (121 patients), and non-osteoporosis (76 patients). Groups were then matched by propensity score using clinical backgrounds affecting bone metabolism.

RESULTS

In non-matched model, serum albumin concentration was significantly associated with osteoporosis-related factors such as aging, inflammation, physical disability, and glucocorticoid dose. Multivariate logistic regression revealed that serum albumin concentration was independently and significantly associated with osteoporosis risk (odds ratio = 0.22, 95% confidence interval = 0.08, 0.61, p = 0.0033). After propensity score matching, 57 patients for each group showed that in addition to the LS and femoral neck T-scores (p < 0.001), serum albumin concentrations (p = 0.01) remained lower in the osteoporosis group compared to non-osteoporosis group. Receiver operating characteristic curve analysis in non-matched model revealed that when cut-off value of serum albumin concentration for indicating osteoporosis was set at 4.2 g/dl, the area under the curve was 0.69, sensitivity 0.74, and specificity 0.58.

CONCLUSIONS

Low serum albumin concentration was significantly and independently associated with the prevalence of osteoporosis, which may be considered as one of the osteoporosis-related factors in postmenopausal patients with RA.

Phase II/III Results of a Trial of Anti-Tumor Necrosis Factor Multivalent NANOBODY Compound Ozoralizumab in Patients With Rheumatoid Arthritis

OBJECTIVE

To assess the efficacy and safety of subcutaneous administration of 30 mg or 80 mg of ozoralizumab plus methotrexate (MTX) in patients with rheumatoid arthritis (RA) whose disease remained active despite MTX therapy.

METHODS

In this multicenter, double-blind, parallel-group, placebo-controlled phase II/III trial, 381 patients were randomized to receive placebo, ozoralizumab 30 mg, or ozoralizumab 80 mg, plus MTX subcutaneously injected every 4 weeks for 24 weeks. The primary end points were the response rates based on the American College of Rheumatology 20% improvement criteria (ACR20) at week 16 and change in the Sharp/van der Heijde score (ΔSHS) from baseline to week 24.

RESULTS

The proportion of patients with an ACR20 response at week 16 was significantly higher (P < 0.001) in both ozoralizumab groups (79.6% for 30 mg, 75.3% for 80 mg), compared with placebo (37.3%); these improvements were observed from the first week of treatment. The proportion of the patients with structural nonprogression (ΔSHS ≤0) was significantly higher in both ozoralizumab groups than in the placebo group. For some secondary end points, significantly greater improvements were observed starting from as early as day 3. Serious adverse events occurred in 4 patients in the ozoralizumab 30-mg group and 5 patients in the ozoralizumab 80-mg group.

CONCLUSION

In patients with active RA who received ozoralizumab in combination with MTX, the signs and symptoms of RA were significantly reduced as compared with the outcomes in those receiving placebo. Ozoralizumab demonstrated acceptable tolerability with no new safety signals when compared with other antibodies against tumor necrosis factor.

A novel anti-TNF-α drug ozoralizumab rapidly distributes to inflamed joint tissues in a mouse model of collagen induced arthritis

In clinical studies, the next-generation anti-tumor necrosis factor-alpha (TNF-α) single domain antibody ozoralizumab showed high clinical efficacy shortly after the subcutaneous injection. To elucidate the mechanism underlying the rapid onset of the effects of ozoralizumab, we compared the biodistribution kinetics of ozoralizumab and adalimumab after subcutaneous injection in an animal model of arthritis. Alexa Fluor 680-labeled ozoralizumab and adalimumab were administered by subcutaneous injection once (2 mg/kg) at five weeks after induction of collagen-induced arthritis (CIA) in an animal arthritis model. The time-course of changes in the fluorescence intensities of the two compounds in the paws and serum were evaluated. The paws of the CIA mice were harvested at four and eight hours after the injection for fluorescence microscopy. Biofluorescence imaging revealed better distribution of ozoralizumab to the joint tissues than of adalimumab, as early as at four hours after the injection. Fluorescence microscopy revealed a greater fluorescence intensity of ozoralizumab in the joint tissues than that of adalimumab at eight hours after the injection. Ozoralizumab showed a significantly higher absorption rate constant as compared with adalimumab. These results indicate that ozoralizumab enters the systemic circulation more rapidly and is distributed to the target tissues earlier and at higher levels than conventional IgG antibodies. Our investigation provides new insight into the mechanism underlying the rapid onset of the effects of ozoralizumab in clinical practice.

Development of an artificial synovial fluid useful for studying Staphylococcus epidermidis joint infections

Staphylococcus epidermidis is a major causative agent of prosthetic joint infections (PJI). The ability to form biofilms supports this highly selective pathogenic potential. In vitro studies essentially relying on phenotypic assays and genetic approaches have provided a detailed picture of the molecular events contributing to biofilm assembly. A major limitation in these studies is the use of synthetic growth media, which significantly differs from the environmental conditions S. epidermidis encounters during host invasion. Building on evidence showing that growth in serum substantially affects S. epidermidis gene expression profiles and phenotypes, the major aim of this study was to develop and characterize a growth medium mimicking synovial fluid, thereby facilitating research addressing specific aspects related to PJI. Using fresh human plasma, a protocol was established allowing for the large-scale production of a medium that by biochemical analysis matches key characteristics of synovial fluid and therefore is referred to as artificial synovial fluid (ASF). By analysis of biofilm-positive, polysaccharide intercellular adhesion (PIA)-producing S. epidermidis 1457 and its isogenic, PIA- and biofilm-negative mutant 1457-M10, evidence is provided that the presence of ASF induces cluster formation in S. epidermidis 1457 and mutant 1457-M10. Consistent with the aggregative properties, both strains formed multilayered biofilms when analyzed by confocal laser scanning microscopy. In parallel to the phenotypic findings, expression analysis after growth in ASF found upregulation of genes encoding for intercellular adhesins (icaA, aap, and embp) as well as atlE, encoding for the major cell wall autolysin being responsible for eDNA release. In contrast, growth in ASF was associated with reduced expression of the master regulator agr. Collectively, these results indicate that ASF induces expression profiles that are able to support intercellular adhesion in both PIA-positive and PIA-negative S. epidermidis. Given the observation that ASF overall induced biofilm formation in a collection of S. epidermidis isolates from PJI, the results strongly support the idea of using growth media mimicking host environments. ASF may play an important role in future studies related to the pathogenesis of S. epidermidis PJI.

Assessment of joint pharmacokinetics and consequences for the intraarticular delivery of biologics

Intraarticular (IA) injections provide the opportunity to deliver biologics directly to their site of action for a local and efficient treatment of osteoarthritis. However, the synovial joint is a challenging site of administration since the drug is rapidly eliminated across the synovial membrane and has limited distribution into cartilage, resulting in unsatisfactory therapeutic efficacy. In order to rationally develop appropriate drug delivery systems, it is essential to thoroughly understand the unique biopharmaceutical environments and kinetics in the joint to adequately simulate them in relevant experimental models. This review presents a detailed view on articular kinetics and drug-tissue interplay of IA administered drugs and summarizes how these can be translated into reasonable formulation strategies by identification of key factors through which the joint residence time can be prolonged and specific structures can be targeted. In this way, pros and cons of the delivery approaches for biologics will be evaluated and the extent to which biorelevant models are applicable to gain mechanistic insights and ameliorate formulation design is discussed.

Albumin-Methotrexate Prodrug Analogues That Undergo Intracellular Reactivation Following Entrance into Cancerous Glioma Cells

A family of monomodified bovine serum albumin (BSA) linked to methotrexate (MTX) through a variety of spacers was prepared. All analogues were found to be prodrugs having low MTX-inhibitory potencies toward dihydrofolate reductase in a cell-free system. The optimal conjugates regenerated their antiproliferative efficacies following entrance into cancerous glioma cell lines and were significantly superior to MTX in an insensitive glioma cell line. A BSA–MTX conjugate linked through a simple ethylene chain spacer, containing a single peptide bond located 8.7 Å distal to the protein back bone, and apart from the covalently linked MTX by about 12 Å, was most effective. The inclusion of an additional disulfide bond in the spacer neither enhanced nor reduced the killing potency of this analogue. Disrupting the native structure of the carrier protein in the conjugates significantly reduced their antiproliferative activity. In conclusion, we have engineered BSA–MTX prodrug analogues which undergo intracellular reactivation and facilitate antiproliferative activities following their entrance into glioma cells.

Psoriasis to Psoriatic Arthritis: The Application of Proteomics Technologies

Psoriatic disease (PsD) is a spectrum of diseases that affect both skin [cutaneous psoriasis (PsC)] and musculoskeletal features [psoriatic arthritis (PsA)]. A considerable number of patients with PsC have asymptomatic synovio-entheseal inflammations, and approximately one-third of those eventually progress to PsA with an enigmatic mechanism. Published studies have shown that early interventions to the very early-stage PsA would effectively prevent substantial bone destructions or deformities, suggesting an unmet goal for exploring early PsA biomarkers. The emergence of proteomics technologies brings a complete view of all involved proteins in PsA transitions, offers a unique chance to map all potential peptides, and allows a direct head-to-head comparison of interaction pathways in PsC and PsA. This review summarized the latest development of proteomics technologies, highlighted its application in PsA biomarker discovery, and discussed the possible clinical detectable PsA risk factors in patients with PsC.

Preparation Technique Affects Recipient Immune Targeting of Autologous Mesenchymal Stem Cells

Fetal bovine serum (FBS) is used for MSC preparation in pre-clinical animal models and veterinary applications, recently in US clinical trials, and for MSC products with current foreign market authorizations. The effect of anti-bovine titers, which are common in animals and humans, has not been investigated. In the equine model, where anti-bovine titers are universally high due to routine vaccination, we evaluated the recipient immune response to autologous MSCs prepared with and without FBS. Preparation of MSCs with FBS resulted in post injection inflammation and antibody mediated cytotoxicity of MSCs when compared to MSCs prepared without FBS. Importantly, synovial MSC concentrations were reduced and LPS induced pain was higher, when FBS was used to prepare MSCs, demonstrating reduced efficacy of FBS prepared MSCs. Fetal bovine serum should no longer be utilized for MSC preparation in pre-clinical study, clinical study, or veterinary applications. The use of FBS in previously reported studies, and in MSC therapeutics with current foreign market authorization, should be considered when interpreting results.

In Vitro Study of the Synergistic Effect of an Enzyme Cocktail and Antibiotics against Biofilms in a Prosthetic Joint Infection Model

Prosthetic joint infections (PJI) are frequent complications of arthroplasties. Their treatment is made complex by the rapid formation of bacterial biofilms, limiting the effectiveness of antibiotic therapy. In this study, we explore the effect of a tri-enzymatic cocktail (TEC) consisting of an endo-1,4-β-d-glucanase, a β-1,6-hexosaminidase, and an RNA/DNA nonspecific endonuclease combined with antibiotics of different classes against biofilms of Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli grown on Ti-6Al-4V substrates. Biofilms were grown in Trypticase soy broth (TSB) with 10 g/liter glucose and 20 g/liter NaCl (TGN). Mature biofilms were assigned to a control group or treated with the TEC for 30 min and then either analyzed or reincubated for 24 h in TGN or TGN with antibiotics. The cytotoxicity of the TEC was assayed against MG-63 osteoblasts, primary murine fibroblasts, and J-774 macrophages using the lactate dehydrogenase (LDH) release test. The TEC dispersed 80.3 to 95.2% of the biofilms' biomass after 30 min. The reincubation of the treated biofilms with antibiotics resulted in a synergistic reduction of the total culturable bacterial count (CFU) compared to that of biofilms treated with antibiotics alone in the three tested species (additional reduction from 2 to more than 3 log₁₀ CFU). No toxicity of the TEC was observed against the tested cell lines after 24 h of incubation. The combination of pretreatment with TEC followed by 24 h of incubation with antibiotics had a synergistic effect against biofilms of S. aureus, S. epidermidis, and E. coli Further studies should assess the potential of the TEC as an adjuvant therapy in in vivo models of PJI.

Cross-matching of allogeneic mesenchymal stromal cells eliminates recipient immune targeting

Allogeneic mesenchymal stromal cells (MSCs) have been used clinically for decades, without cross-matching, on the assumption that they are immune-privileged. In the equine model, we demonstrate innate and adaptive immune responses after repeated intra-articular injection with major histocompatibility complex (MHC) mismatched allogeneic MSCs, but not MHC matched allogeneic or autologous MSCs. We document increased peri-articular edema and synovial effusion, increased synovial cytokine and chemokine concentrations, and development of donor-specific antibodies in mismatched recipients compared with recipients receiving matched allogeneic or autologous MSCs. Importantly, in matched allogeneic and autologous recipients, but not mismatched allogeneic recipients, there was increased stromal derived factor-1 along with increased MSC concentrations in synovial fluid. Until immune recognition of MSCs can be avoided, repeated clinical use of MSCs should be limited to autologous or cross-matched allogeneic MSCs. When non-cross-matched allogeneic MSCs are used in single MSC dose applications, presensitization against donor MHC should be assessed.

Antioxidant Carbon Nanoparticles Inhibit Fibroblast-Like Synoviocyte Invasiveness and Reduce Disease Severity in a Rat Model of Rheumatoid Arthritis

Reactive oxygen species have been involved in the pathogenesis of rheumatoid arthritis (RA). Our goal was to determine the effects of selectively scavenging superoxide (O2•-) and hydroxyl radicals with antioxidant nanoparticles, called poly(ethylene glycol)-functionalized hydrophilic carbon clusters (PEG-HCCs), on the pathogenic functions of fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA) and on the progression of an animal model of RA. We used human FLS from patients with RA to determine PEG-HCC internalization and effects on FLS cytotoxicity, invasiveness, proliferation, and production of proteases. We used the pristane-induced arthritis (PIA) rat model of RA to assess the benefits of PEG-HCCs on reducing disease severity. PEG-HCCs were internalized by RA-FLS, reduced their intracellular O2•-, and reduced multiple measures of their pathogenicity in vitro, including proliferation and invasion. In PIA, PEG-HCCs caused a 65% reduction in disease severity, as measured by a standardized scoring system of paw inflammation and caused a significant reduction in bone and tissue damage, and circulating rheumatoid factor. PEG-HCCs did not induce lymphopenia during PIA. Our study demonstrated a role for O2•- and hydroxyl radicals in the pathogenesis of a rat model of RA and showed efficacy of PEG-HCCs in treating a rat model of RA.

Methotrexate-loaded multifunctional nanoparticles with near-infrared irradiation for the treatment of rheumatoid arthritis

Backgrounds

Despite the advances of rheumatoid arthritis (RA) therapeutics, several patients do not receive adequate treatment due to the toxicity and/or insufficient response of drugs. The aim of this study is to design photothermally controlled drug release from multifunctional nanoparticles (MNPs) at a near-infrared (NIR) irradiated site to improve therapeutic efficacy for RA and reduce side effects.

Methods

Au film was deposited onto methotrexate (MTX)-loaded poly(ethylene glycol)-poly(lactic-co-glycolic acid) (PLGA) nanoparticles, resulting in MTX-loaded MNPs. The synergistic effects of MTX-loaded MNPs with NIR irradiation were investigated using RA fibroblast-like synoviocytes (FLSs) and collagen-induced arthritis (CIA) mice.

Results

Upon NIR irradiation, NIR resonance of the Au half-shell generated heat locally, accelerating MTX release from PLGA nanoparticles. In vivo NIR images of MTX-loaded MNPs indicated effective delivery of the MNPs to the inflamed joints. Moreover, in collagen-induced arthritis mice, MTX-loaded MNPs containing 1/1400 of MTX solution (repeated-dose administration) had therapeutic effects comparable to conventional treatment with MTX solution. In vitro experiments showed higher therapeutic efficacy of MTX-loaded MNPs with NIR irradiation than that of chemotherapy alone.

Conclusions

A combination therapy of MTX-loaded MNP and NIR irradiation showed durable and good treatment efficacy for the suppression of arthritis in a single administration of small dose of MTX. Our results demonstrate that the treatment modality using drug-loaded MNP with NIR irradiation may be a promising therapeutic strategy for the treatment of RA and allow in vivo NIR optical imaging.

Targeted drug-delivery systems in the treatment of rheumatoid arthritis: recent advancement and clinical status

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that is characterized by synovial inflammation, cellular infiltration in joints which leads to progressive joint destruction and bone erosion. RA is associated with many comorbidities including pulmonary disease, rheumatoid nodules and can have a pessimistic impact on quality of life. The current therapies of RA treatment comprise conventional, small molecule and biological antirheumatic drugs. Their utility as therapeutic agents is limited because of poor absorption, rapid metabolism and adverse effects (dose-escalation, systemic toxicity, lack of selectivity and safety). To overcome these limitations, the novel drug delivery systems are being investigated. This review has compiled currently approved therapies along with emerging advanced drug-delivery systems for RA treatment. Further, active targeting of therapeutic agents to inflamed joints via folate receptor, CD44, angiogenesis, integrins and other provided an improved therapeutic efficacy in the treatment of RA.

Platelets Disseminate Extracellular Vesicles in Lymph in Rheumatoid Arthritis

OBJECTIVE

The lymphatic system is a circulatory system that unidirectionally drains the interstitial tissue fluid back to blood circulation. Although lymph is utilized by leukocytes for immune surveillance, it remains inaccessible to platelets and erythrocytes. Activated cells release submicron extracellular vesicles (EV) that transport molecules from the donor cell. In rheumatoid arthritis, EV accumulate in the joint where they can interact with numerous cellular lineages. However, whether EV can exit the inflamed tissue to recirculate is unknown. Here, we investigated whether vascular leakage that occurs during inflammation could favor EV access to the lymphatic system. Approach and Results: Using an in vivo model of autoimmune inflammatory arthritis, we show that there is an influx of platelet EV, but not EV from erythrocytes or leukocytes, in joint-draining lymph. In contrast to blood platelet EV, lymph platelet EV lacked mitochondrial organelles and failed to promote coagulation. Platelet EV influx in lymph was consistent with joint vascular leakage and implicated the fibrinogen receptor α2bβ3 and platelet-derived serotonin.

CONCLUSIONS

These findings show that platelets can disseminate their EV in fluid that is inaccessible to platelets and beyond the joint in this disease.

An effective and safe treatment strategy for rheumatoid arthritis based on human serum albumin and Kolliphor® HS 15

Aim: We aimed to construct human serum albumin-Kolliphor® HS 15 nanoparticles (HSA-HS15 NPs) to overcome the limitations in targeted therapy for rheumatoid arthritis (RA) and enhance the safety of drug-loaded HSA NPs. Methodology: Celastrol (CLT)-loaded HSA-HS15 NPs were prepared and the properties were adequately investigated; the treatment effect were evaluated in RA rats; in vitro and in vivo studies were performed to explain the mechanism. Results: CLT-HSA-HS15 NPs had remarkable treatment ability and enhanced safety in the treatment of RA compared with free CLT and CLT-HSA NPs. Conclusion: HSA-HS15 NPs could be a safe and efficient therapeutic strategy for the treatment of RA, because of the inflammatory targeting ability of albumin, the added HS15 and ELVIS effect (extravasation through leaky vasculature followed by inflammatory cell-mediated sequestration) of nanoparticles.

Role of Liposome Size, Surface Charge, and PEGylation on Rheumatoid Arthritis Targeting Therapy

Rheumatoid arthritis (RA) is a chronic, systemic, progressive autoimmune disease. The vascular permeability of inflamed joints in RA makes it a natural candidate for passive targeting, similar to the enhanced permeability and retention (EPR) effect in solid tumors. Thus, various therapeutic drugs have been encapsulated in nanocarriers to achieve longer in vivo circulation times and improve RA targeting. Although liposomes are the most widely used nanocarriers for RA treatment, the effects of physical and chemical characteristics of liposomes, such as particle sizes, surface charge, polyethylene glycol (PEG) chain length, and PEG concentration, on their passive RA targeting effect have not been fully elucidated. Here, we systematically investigated the effects of physical and chemical properties of liposomes on circulation time and conducted preliminary studies on their passive targeting mechanisms. A series of liposomes with different particle sizes (70, 100, 200, and 350 nm), surface charges (positive, negative, slight positive, and slight negative), PEG chain lengths (1, 2, and 5 kDa), and concentrations (5, 10, and 20% w/w of total lipid) were prepared by lipid film dispersion and extrusion. The pharmacokinetics of liposomes with different formulas were evaluated with a fluorescence microplate reader. A collagen-induced arthritis (CIA) mouse model was utilized to mimic RA pathological conditions and to evaluate the targeting and efficacy of liposomes with different properties using a near-infrared fluorescence imaging system. Uptake of fluorescent liposomes by various synovial cells was measured by flow cytometry. The results indicated that liposomes with 100 nm diameter, a slight negative charge, and 10% incorporation of 5 kDa PEG had better in vivo circulation time and inflamed joint targeting than did other liposomes. Dexamethasone (Dex) was encapsulated into optimized liposomes as an active ingredient for RA treatment. Pharmacodynamic studies demonstrated that Dex liposomes could significantly improve the antiarthritic efficacy of Dex in a CIA mouse model of RA. This study also found that the retention mechanism of RA was mainly increased because of the uptake of liposomes by fibroblasts and macrophages in inflamed joints. This study provides a persuasive explanation for passive RA targeting by liposomes and advances our ability to treat RA with nanomedicine.

Navigating albumin-based nanoparticles through various drug delivery routes

As a natural polymer, albumin is well-received for being nontoxic, nonimmunogenic, biodegradable and biocompatible. Together with its targeting potential on specific cells, albumin-based nanoparticles appear as an effective carrier for various therapeutics. In recent years, there has been an increasing number of studies investigating the use of albumin-based nanoparticles across different administration routes. Although each route and target tissue presents a distinct anatomical and physiological profile that demands specific consideration, pharmaceuticals could still be delivered effectively via albumin-based nanoparticles. Therefore, this review discusses the features that warrant such applications across various delivery routes and explores their possibilities in other administration routes. The challenges associated with its use will also be elaborated to provide a holistic consideration to realise their clinical potentials.

Design of a ligand for cancer imaging with long blood circulation and an enhanced accumulation ability in tumors

The use of imaging agents to visualize tumor cells is an advantageous technique to achieve a more efficient intraoperative diagnosis and effective debulking operations. Targeting of these agents to certain receptors that are overexpressed in cancer cells, such as the folate receptor, aids in tumor targeting. Several imaging probes have been developed using this strategy. However, these ligand-targeting cancer imaging probes are rapidly cleared during systemic delivery due to their small size, which compromises their biodistribution and circulation. Improving the detection of cancer requires higher accumulation and effective retention activities of imaging probes. Here we developed a new design for a folate-fluorophore conjugate that is modified with palmitoyl. Palmitic acid has a strong binding affinity with human serum albumin (HSA), which has the ability to form non-covalent host-guest complexes and has a blood half-life of 19 days. In this strategy, HSA is expected to serve as an endogenous nanocarrier for the designed probe in blood circulation. We hypothesized that via a reversible interaction with HSA, this simple palmitoyl modification on a folate-fluorophore conjugate can induce long blood circulation of the probe. Our folate-targeted probe could show longer blood circulation compared to the probe which lacks palmitoyl.

Cellular and molecular perspectives in rheumatoid arthritis

Synovial immunopathology in rheumatoid arthritis is complex involving both resident and infiltrating cells. The synovial tissue undergoes significant neovascularization, facilitating an influx of lymphocytes and monocytes that transform a typically acellular loose areolar membrane into an invasive tumour-like pannus. The microvasculature proliferates to form straight regularly-branching vessels; however, they are highly dysfunctional resulting in reduced oxygen supply and a hypoxic microenvironment. Autoantibodies such as rheumatoid factor and anti-citrullinated protein antibodies are found at an early stage, often before arthritis has developed, and they have been implicated in the pathogenesis of RA. Abnormal cellular metabolism and mitochondrial dysfunction thus ensue and, in turn, through the increased production of reactive oxygen species actively induce inflammation. Key pro-inflammatory cytokines, chemokines and growth factors and their signalling pathways, including nuclear factor κB, Janus kinase-signal transducer, are highly activated when immune cells are exposed to hypoxia in the inflamed rheumatoid joint show adaptive survival reactions by activating. This review attempts to highlight those aberrations in the innate and adaptive immune systems including the role of genetic and environmental factors, autoantibodies, cellular alterations, signalling pathways and metabolism that are implicated in the pathogenesis of RA and may therefore provide an opportunity for therapeutic intervention.

High-Performance Liquid Chromatography (HPLC) Quantification of Liposome-Delivered Doxorubicin in Arthritic Joints of Collagen-Induced Arthritis Rats

Background

Neoangiogenesis occurring in inflamed articular synovium in early rheumatoid arthritis (RA) is characterized by enhanced vascular permeability that allows nanoparticle agents, including liposomes, to deliver encapsulated drugs to arthritic joints and subsequently improve therapeutic efficacy and reduce adverse effects. However, the targeting distribution of liposomes in arthritic joints during RA has not been quantitatively demonstrated. We performed this study to evaluate the targeting distribution of PEGylated doxorubicin liposomes in the arthritic joints of collagen-induced arthritis (CIA) rats by high-performance liquid chromatography (HPLC).

Material/Methods

Two doxorubicin formulations were administered to CIA rats via tail intravenous injection at a single dose (50 mg/m²). CIA rats were sacrificed and the tissues of the inflamed ankle joints were collected. The content of doxorubicin in the arthritic joints was analyzed by a validated and reproducible HPLC method. A two-way ANOVA for 2×5 factorial design was used for statistical analysis.

Results

The developed HPLC method was sensitive, precise, and reproducible. The method was successfully applied to quantify doxorubicin content in arthritic tissues. At each time point (6, 12, 24, 48, and 72 h), doxorubicin content in the arthritic joints of the doxorubicin liposome group (DOX-LIP group) was higher than in the free doxorubicin group (DOX group) (P<0.05). In the DOX-LIP group, doxorubicin levels in the arthritic joints increased gradually and significantly in the interval of 6–72 h post-administration.

Conclusions

PEGylated doxorubicin liposomes were targeted to, accumulated, and retained in the arthritic joints of CIA rats. The present study indicates that liposome encapsulation increases the therapeutic efficacy of antirheumatic drugs, presenting a promising therapeutic strategy for RA.

Dendritic polyglycerol anions for the selective targeting of native and inflamed articular cartilage

Dye-conjugated polyanions show high affinities toward native and inflamed cartilage dependent on the anionic moiety and the condition of the tissue.

Fibroblastic synoviocytes secrete plasma proteins via α2 -macroglobulins serving as intracellular and extracellular chaperones

Changes in plasma protein levels in synovial fluid (SF) have been implicated in osteoarthritis and rheumatoid arthritis. It was previously thought that the presence of plasma proteins in SF reflected ultrafiltration or extravasation from the vasculature, possibly due to retraction of inflamed endothelial cells. Recent proteomic analyses have confirmed the abundant presence of plasma proteins in SF from control and arthritic patients. Systematic depletion of high-abundance plasma proteins from SF and conditioned media from synoviocytes cultured in serum, and protein analysis under denaturing/reducing conditions have limited our understanding of sources and the native structures of "plasma protein" complexes in SF. Using Western blotting, qPCR, and mass spectrometry, we found that Hig-82 lapine fibroblastic synovicytes cultured under serum-free conditions expressed and secreted plasma proteins, including the cytokine-binding protein secreted phosphoprotein 24 kDa (Spp24) and many of the proteases and protease inhibitors found in SF. Treating synoviocytes with TGF-β1 or BMP-2 for 24 h upregulated the expression of plasma proteins, including Spp24, α2 -HS-glycoprotein, α1 -antitrypsin, IGF-1, and C-reactive protein. Furthermore, many of the plasma proteins of mass <151 kDa were secreted as disulfide-bound complexes with members of the α2 -macroglobulin (A2M) family, which serve as intracellular and extracellular chaperones, not protease inhibitors. Using brefeldin A to block vesicular traffic and protease inhibitors to inhibit endogenous activation of naïve A2M, we demonstrated that the complexes were formed in the endoplasmic reticulum lumen and that Ca(2+) cysteine protease-dependent processes are involved.

Synovial fluid total protein concentration as a possible marker for canine idiopathic polyarthritis

Idiopathic polyarthritis (IPA) is a very common inflammatory arthropathy in the dog. Canine IPA is diagnosed mainly by detecting increased number of leukocytes in the synovial fluid (SF), which is easily influenced by glucocorticoid therapy. We obtained 31 SF samples from 24 IPA dogs prior to (n=19) and/or after (n=12) 1 to 10 weeks of glucocorticoid therapy. The SF total protein concentrations of IPA dogs were significantly higher than those of dogs with non-arthritis diseases (n=34) and healthy controls (n=10). Our data revealed that the SF total protein concentrations are not influenced by several weeks of glucocorticoid therapy. Hence, the SF total protein concentration is applicable as a diagnostic marker of canine IPA even when the patients are receiving glucocorticoid therapy.

Programming Bioactive Architectures with Cyclic Peptide Amphiphiles

We present a versatile approach for the synthesis of cyclic peptide amphiphiles of the hormone somatostatin (SST) with tunable lipophilic tails to program bioactive nanoarchitectures. A novel bis-alkylation reagent is synthesized that facilitates the functionalization of SST with a thiol anchor. Different hydrophobic moieties are introduced inspired by a biomimetic palmitoylation approach which opens access to cyclic peptide amphiphiles that display rich self-organization and cell membrane interactions.

Signs and symptoms after temporomandibular joint washing and cannula placement assessed by cone beam computerized tomography

OBJECTIVE

Analyses of temporomandibular joint synovial fluid using the hydroxocobalamin push-pull technique are increasingly used. However, objective complications and subjective experiences from this procedure have not been described. Firstly, this study aimed to describe discomfort and potential side-effects of this method with special emphasis on symptoms related to the arthrocentesis to be used for future patient information and Ethical Committee applications. Secondly, this study aimed to evaluate the use of cone beam computed tomography (CBCT) as control of intra-capsular cannula placement.

METHODS

Twenty healthy, young adult volunteers were included. Extensive objective and subjective questionnaires were completed before and 14 days after the synovial fluid sampling. With the cannula inside the joints a CBCT was done to investigate if this procedure can be used to verify intra-capsular cannula position.

RESULTS

The subjective findings: Most subjects did experience mild pain or discomfort post-operatively. In 12 of 20 subjects symptoms had resolved after 2 days and no subjects had symptoms for more than a week. The longer lasting symptoms were mainly transient joint sounds on mandibular movement. Objective findings: 14 days after the sampling mandibular protrusion had improved 1 mm, but all other objective measures were equal compared to baseline. CBCT showed a large variation in cannula position and no conclusions could be drawn from this.

CONCLUSION

The hydroxocobalamin push-pull synovial fluid sampling may cause minor, transient symptoms. CBCT does not seem to provide any clinical benefits concerning the correct cannula position in relation to the upper joint compartment and disc.

Drug-loaded gold/iron/gold plasmonic nanoparticles for magnetic targeted chemo-photothermal treatment of rheumatoid arthritis

We have developed methotrexate (MTX)-loaded poly(lactic-co-glycolic acid, PLGA) gold (Au)/iron (Fe)/gold (Au) half-shell nanoparticles conjugated with arginine-glycine-aspartic acid (RGD), which can be applied for magnetic targeted chemo-photothermal treatment, and in vivo multimodal imaging of rheumatoid arthritis (RA). Upon near-infrared (NIR) irradiation, local heat is generated at the inflammation region due to the NIR resonance of Au half-shells and MTX release from PLGA nanoparticles is accelerated. The Fe half-shell layer embedded between the Au half-shell layers enables in vivo T2-magnetic resonance (MR) imaging in addition to NIR absorbance imaging. Furthermore, the delivery of the nanoparticles to the inflammation region in collagen-induced arthritic (CIA) mice, and their retention can be enhanced under external magnetic field. When combined with consecutive NIR irradiation and external magnetic field application, these nanoparticles provide enhanced therapeutic effects with an MTX dosages of only 0.05% dosage compared to free MTX therapy for the treatment of RA.

The human knee: A window on the microvasculature

In synovial joints, the lining cells do not have tight junctions with their neighboring cells and they have no underlying basement membrane. Therefore, the synovial fluid within the articular cavity is continuous with the interstitial fluid of the synovial intima. These features, combined with ready access to the space via arthrocentesis, permit quantitative studies of microvascular function in the knees of unanesthetized, volunteer, human subjects both with and without chronic arthritis. This brief article reviews the principal findings of such work over ∼40 years at the University of Washington. Examined variables include bidirectional fenestral diffusion of small solutes, effective blood flow, lymphatic drainage, and endothelial pore size and permeability. The latter work introduced a new method using gel filtration chromatography of paired synovial fluid (SF) and serum (S) to obtain essentially continuous SF/S ratios over a range of radii between 1 and 12 nanometers.

Structure and Size-selective Permeability of the Synovial Membrane of the Temporomandibular Joint of the Mouse Measured by MR Imaging at 7T

PURPOSE

We analyzed the anatomical structure of the temporomandibular joint (TMJ) and molecular weight dependency of synovial membrane permeability in mice using 7-tesla magnetic resonance (MR) imaging.

METHODS

We obtained 3-dimensional (3D) T1-weighted gradient echo (3D-T1W) and 3D T2-weighted rapid acquisition with relaxation enhancement (3D-T2W RARE) MR images of the TMJ of male C57BL6 mice with voxel resolution of 65 µm. Two-dimensional (2D) T1w images were measured every 45 s before and after bolus intravenous (IV) injection of contrast reagents: gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA; 0.5 kDa); oligomer-based contrast agent (CH3-DTPA-Gd; 2.1 kDa); gadolinium-labeled polylysine (Gd-polylysine; 10 kDa); and gadolinium-labeled albumin (Gd-albumin; 74 kDa).

RESULTS

T1W images depicted the temporal bone and mandibular condyle as regions with lower signal intensity and the disc as a region of intermediate intensity. In the Gd-DTPA-enhanced T1W and T2W images, the articular disc could be identified as a region with lower signal intensity than that of the upper and lower joint cavities. After IV injection of Gd-DTPA or CH3-DTPA-Gd, the signal intensity of the joint cavities increased within 10 min, but this increase was not shown with Gd-polylysine and Gd-albumin.

CONCLUSION

The structural findings obtained by MR imaging agreed with those obtained by hematoxylin-eosin staining under light microscopy. Contrast-enhanced MR imaging suggested that smaller (<2.1 kDa) but not larger (>10 kDa) molecules can permeate the synovial membrane. Our results suggest the utility of MR imaging for analyzing the structure of the TMJ as well as permeability of the synovial membrane.

A normative study of the synovial fluid proteome from healthy porcine knee joints

Synovial fluid in an articulating joint contains proteins derived from the blood plasma and proteins that are produced by cells within the joint tissues, such as synovium, cartilage, ligament, and meniscus. The proteome composition of healthy synovial fluid and the cellular origins of many synovial fluid components are not fully understood. Here, we present a normative proteomics study using porcine synovial fluid. Using our optimized method, we identified 267 proteins with high confidence in healthy synovial fluid. We also evaluated mRNA expression data from tissues that can contribute to the synovial fluid proteome, including synovium, cartilage, blood, and liver, to better estimate the relative contributions from these sources to specific synovial fluid components. We identified 113 proteins in healthy synovial fluid that appear to be primarily derived from plasma transudates, 37 proteins primarily derived from synovium, and 11 proteins primarily derived from cartilage. Finally, we compared the identified synovial fluid proteome to the proteome of human plasma, and we found that the two body fluids share many similarities, underlining the detected plasma derived nature of many synovial fluid components. Knowing the synovial fluid proteome of a healthy joint will help to identify mechanisms that cause joint disease and pathways involved in disease progression.

Delineating the synovial fluid proteome: recent advancements and ongoing challenges in biomarker research

There is an urgent need for identifying novel serum biomarkers that can be used to improve diagnosis, predict disease progression or response to therapy, or serve as therapeutic targets for rheumatic diseases. Synovial fluid (SF) is secreted by and remains in direct contact with the synovial membrane, and can reflect the biochemical state of the joint under different physiological and pathological conditions. Therefore, SF is regarded as an excellent source for identifying biomarkers of rheumatologic diseases. The use of high-throughput and/or quantitative proteomics and sophisticated computational software applied to analyze the protein content of SF has been well-adopted as an approach to finding novel arthritis biomarkers. This review will focus on some of the potential pitfalls of biomarker studies using SF, summarize the status of the field of SF proteomics in general, as well as discuss some of the most promising biomarker study approaches using proteomics. A brief status of the biomarker discovery efforts in rheumatoid arthritis, osteoarthritis and juvenile idiopathic arthritis is also provided.