Catabolic and anabolic periarticular bone changes in patients with rheumatoid arthritis: a computed tomography study on the role of age,disease duration and bone markers

Introduction

The aim of this study was to determine the factors, including markers of bone resorption and bone formation, which determine catabolic and anabolic periarticular bone changes in patients with rheumatoid arthritis (RA).

Methods

Forty RA patients received high-resolution peripheral quantitative computed tomography (HR-pQCT) analysis of the metacarpophalangeal joints II and III of the dominantly affected hand at two sequential time points (baseline, one year follow-up). Erosion counts and scores as well as osteophyte counts and scores were recorded. Simultaneously, serum markers of bone resorption (C-terminal telopeptide of type I collagen (CTX I), tartrate-resistant acid phosphatase 5b (TRAP5b)), bone formation (bone alkaline phosphatase (BAP), osteocalcin (OC)) and calcium homeostasis (parathyroid hormone (PTH), 25-hydroxyvitamin D3 (Vit D)) were assessed. Bone biomarkers were correlated to imaging data by partial correlation adjusting for various demographic and disease-specific parameters. Additionally, imaging data were analyzed by mixed linear model regression.

Results

Partial correlation analysis showed that TRAP5b levels correlate significantly with bone erosions, whereas BAP levels correlate with osteophytes at both time points. In the mixed linear model with erosions as the dependent variable, disease duration (P <0.001) was the key determinant for these catabolic bone changes. In contrast, BAP (P = 0.001) as well as age (P = 0.018), but not disease duration (P = 0.762), were the main determinants for the anabolic changes (osteophytes) of the periarticular bone in patients with RA.

Conclusions

This study shows that structural bone changes assessed with HR-pQCT are accompanied by alterations in systemic markers of bone resorption and bone formation. Besides, it can be shown that bone erosions in RA patients depend on disease duration, whereas osteophytes are associated with age as well as serum level of BAP. Therefore, these data not only suggest that different variables are involved in formation of bone erosions and osteophytes in RA patients, but also that periarticular bone changes correlate with alterations in systemic markers of bone metabolism, pointing out BAP as an important parameter.     

The evolving systemic and local biomarker milieu at different stages of disease progression in rat collagen-induced arthritis

Rats with collagen-induced arthritis (CIA) were necropsied on 14 occasions from 4 days after induction to 27 days after disease onset to evaluate the kinetics of local (joint protein extracts) and systemic (serum) levels of inflammatory and pro-erosive factors. Systemic increases in α1 acid glycoprotein and KC/GRO together with systemic and local enrichment of interleukin (IL)-1β, IL-6, CCL2, transforming growth factor (TGF)-β and elevated IL-1α and IL-18 in joint extracts preceded the onset of clinical disease. Systemic upregulation of IL-1β, IL-6, TGF-β CCL2, RANKL and prostaglandin E₂ (PGE₂) during acute and/or chronic CIA coincided with systemic leukocytosis and a CD4+ T-cell increase in blood and spleen. In contrast, progression of joint erosions during clinical CIA was associated with intra-articular increases in IL-1α/β, IL-6, IL-18, CCL2, KC/GRO and RANKL, and a dramatic decline in osteoprotegerin (OPG). These data indicate that systemic and local events in inflammatory arthritis can be discrete processes, driven by multiple cellular and humoral mediators with distinct temporospatial profiles.     

MTRX1011A,a humanized anti-CD4 monoclonal antibody,in the treatment of patients with rheumatoid arthritis: a Phase I randomized,double-blind,placebo-controlled study incorporating pharmacodynamic biomarker assessments

Introduction  

The purpose of this study was to evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of the humanized anti-CD4 monoclonal antibody MTRX1011A in a randomized, double-blind placebo-controlled Phase 1 study in patients with rheumatoid arthritis (RA).     

Molecular basis of recognition of human osteopontin by 23C3, a potential therapeutic antibody for treatment of rheumatoid arthritis

Osteopontin plays an important role in the development and perpetuation of rheumatoid arthritis (RA). Antibodies targeting osteopontin have shown promising therapeutic benefits against this disease. We have previously reported a novel anti-RA monoclonal antibody, namely, 23C3, and shown it capable of alleviating the symptoms of RA in a murine collagen-induced arthritis model, restoring the cytokine production profile in joint tissues, and reducing T-cell recall responses to collagen type II. We describe here the crystal structure of 23C3 in complex with its epitope peptide. Analyses of the complex structure reveal the molecular mechanism of osteopontin recognition by 23C3. The peptide folds into two tandem β-turns, and two key residues of the peptide are identified to be critical for the recognition by 23C3: TrpP43 is deeply embedded into a hydrophobic pocket formed by AlaL34, TyrL36, LeuL46, TyrL49, PheL91, and MetH102 and therefore has extensive hydrophobic interactions with 23C3, while AspP47 has a network of hydrophilic interactions with residues ArgH50, ArgH52, SerH53, and AsnH56 of the antibody. Besides the complementarity-determining region loops, the framework region L2 of 23C3 is also shown to interact with the epitope peptide, which is not common in the antibody-antigen interactions and thus could be exploited in the engineering of 23C3. These results not only provide valuable information for further improvement of 23C3 such as chimerization or humanization for its therapeutic application, but also reveal the features of this specific epitope of osteopontin that may be useful for the development of new antibody drugs against RA.     

Early restoration of immune and vascular phenotypes in systemic lupus erythematosus and rheumatoid arthritis patients after B cell depletion

This translational multi‐centre study explored early changes in serologic variables following B lymphocyte depletion by rituximab (RTX) treatment in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) patients and investigated in vitro effects on the activity of other immune cells and the vascular endothelium. Eighty‐five SLE patients, seventy‐five RA patients and ninety healthy donors were enrolled. Two additional cohorts of selected SLE and RA patients were treated with RTX for 3 months. Changes in circulating levels of inflammatory mediators, oxidative stress markers and NETosis‐derived bioproducts were evaluated. Serum miRNomes were identified by next‐generation sequencing, and RTX‐induced changes were delineated. Mechanistic in vitro studies were performed to assess activity profiles. Altered inflammatory, oxidative and NETosis‐derived biomolecules were found in SLE and RA patients, closely interconnected and associated to specific miRNA profiles. RTX treatment reduced SLE and RA patients' disease activity, linked to a prominent alteration in those biomolecules and the reversal of altered regulating miRNAs. In vitro studies showed inhibition of NETosis and decline of pro‐inflammatory profiles of leucocytes and human umbilical vein endothelial cells (HUVECs) after B cell depletion. This study provides evidence supporting an early RTX‐induced re‐setting of the pro‐inflammatory status in SLE and RA, involving a re‐establishment of the homeostatic equilibrium in immune system and the vascular wall.     

Filifactor alocis and Dialister pneumosintes in a Mexican population affected by periodontitis and rheumatoid arthritis: An exploratory study

Filifactor alocis and Dialister pneumosintes have been associated with the initiation and progression of periodontitis (PE). We determined and compared the frequency of both bacteria in patients with PE, rheumatoid arthritis (RA), and PE/RA simultaneously. Detection was performed by polymerase chain reaction in the subgingival biofilm. Bacteria were more frequent in patients with PE, and clinical periodontal parameters such as pocket depth (PD) and clinical attachment loss (CAL) were significantly higher in patients with PE/RA. F. alocis and D. pneumosintes could influence PD and CAL, hence participating in the initiation and progression of PE in patients with RA.     

The inhibitory effects of a RANKL-binding peptide on articular and periarticular bone loss in a murine model of collagen-induced arthritis: a bone histomorphometric study

IntroductionWe designed OP3-4 (YCEIEFCYLIR), a cyclic peptide, to mimic the soluble osteoprotegerin (OPG), and was proven to bind to RANKL (receptor activator of NF-κB ligand), thereby inhibiting osteoclastogenesis. We recently found that another RANKL binding peptide, W9, could accelerate bone formation by affecting RANKL signaling in osteoblasts. We herein demonstrate the effects of OP3-4 on bone formation and bone loss in a murine model of rheumatoid arthritis.MethodsTwenty-four seven-week-old male DBA/1J mice were used to generate a murine model of collagen-induced arthritis (CIA). Then, vehicle or OP3-4 (9 mg/kg/day or 18 mg/kg/day) was subcutaneously infused using infusion pumps for three weeks beginning seven days after the second immunization. The arthritis score was assessed, and the mice were sacrificed on day 49. Thereafter, radiographic, histological and biochemical analyses were performed.ResultsThe OP3-4 treatment did not significantly inhibit the CIA-induced arthritis, but limited bone loss. Micro-CT images and quantitative measurements of the bone mineral density revealed that 18 mg/kg/day OP3-4 prevented the CIA-induced bone loss at both articular and periarticular sites of tibiae. As expected, OP3-4 significantly reduced the CIA-induced serum CTX levels, a marker of bone resorption. Interestingly, the bone histomorphometric analyses using undecalcified sections showed that OP3-4 prevented the CIA-induced reduction of bone formation-related parameters at the periarticular sites.ConclusionThe peptide that mimicked OPG prevented inflammatory bone loss by inhibiting bone resorption and stimulating bone formation. It could therefore be a useful template for the development of small molecule drugs for inflammatory bone loss.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0753-8) contains supplementary material, which is available to authorized users.     

Simultaneous targeting of TNF and Ang2 with a novel bispecific antibody enhances efficacy in an in vivo model of arthritis

Despite the clinical success of anti-tumor necrosis factor (TNF) therapies in the treatment of inflammatory conditions such as rheumatoid arthritis, Crohn disease and psoriasis, full control of the diseases only occurs in a subset of patients and there is a need for new therapeutics with improved efficacy against broader patient populations. One possible approach is to combine biological therapeutics, but both the cost of the therapeutics and the potential for additional toxicities needs to be considered. In addition to the various mediators of immune and inflammatory pathways, angiogenesis is reported to contribute substantially to the overall pathogenesis of inflammatory diseases. The combination of an anti-angiogenic agent with anti-TNF into one molecule could be more efficacious without the risk of severe immunosuppression. To evaluate this approach with our Zybody technology, we generated bispecific antibodies that contain an Ang2 targeting peptide genetically fused to the anti-TNF antibody adalimumab (Humira®). The bispecific molecules retain the binding and functional characteristics of the anti-TNF antibody, but with additional activity that neutralizes Ang2. In a TNF transgenic mouse model of arthritis, the bispecific anti-TNF-Ang2 molecules showed a dose-dependent reduction in both clinical symptoms and histological scores that were significantly better than that achieved by adalimumab alone.     

Simultaneous targeting of TNF and Ang2 with a novel bispecific antibody enhances efficacy in an in vivo model of arthritis

Despite the clinical success of anti-tumor necrosis factor (TNF) therapies in the treatment of inflammatory conditions such as rheumatoid arthritis, Crohn disease and psoriasis, full control of the diseases only occurs in a subset of patients and there is a need for new therapeutics with improved efficacy against broader patient populations. One possible approach is to combine biological therapeutics, but both the cost of the therapeutics and the potential for additional toxicities needs to be considered. In addition to the various mediators of immune and inflammatory pathways, angiogenesis is reported to contribute substantially to the overall pathogenesis of inflammatory diseases. The combination of an anti-angiogenic agent with anti-TNF into one molecule could be more efficacious without the risk of severe immunosuppression. To evaluate this approach with our Zybody technology, we generated bispecific antibodies that contain an Ang2 targeting peptide genetically fused to the anti-TNF antibody adalimumab (Humira®). The bispecific molecules retain the binding and functional characteristics of the anti-TNF antibody, but with additional activity that neutralizes Ang2. In a TNF transgenic mouse model of arthritis, the bispecific anti-TNF-Ang2 molecules showed a dose-dependent reduction in both clinical symptoms and histological scores that were significantly better than that achieved by adalimumab alone.     

Antioxidant,hepatoprotective, genoprotective,and cytoprotective effects of quercetin in a murine model of arthritis

Rheumatoid arthritis is a highly debilitating inflammatory autoimmune disease which is characterized by joint destruction. The present study sought to investigate the effect of quercetin in rats with complete Freund's adjuvant-induced arthritis. Animals were divided into control/saline, control/quercetin (5 mg/kg, 25 mg/kg, and 50 mg/kg) arthritis/saline, and arthritis/quercetin (5 mg/kg, 25 mg/kg, and 50 mg/kg); the treatments were administered for 45 days. Biochemical, oxidative stress, genotoxicity, and cytotoxicity parameters were evaluated. All doses of quercetin reduced the levels of aspartate aminotransferase, thiobarbituric acid-reactive substances, and reactive oxygen species; however, only treatment with 25 or 50 mg/kg increased catalase activity. Total thiol and reduced glutathione levels were not significantly affected by the induction nor by the treatments. Genotoxicity assessed by DNA damage, and cytotoxicity through picogreen assay, decreased after treatments with quercetin. Our results present evidence of the antioxidant, cytoprotective, genoprotective and hepatoprotective, and effects of quercetin, demonstrating its potential as a candidate for coadjuvant therapy.     

Syndecan-4 involves in the pathogenesis of rheumatoid arthritis by regulating the inflammatory response and apoptosis of fibroblast-like synoviocytes

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, and the pathogenesis of RA is still unknown. Rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) are of significance in the pathogenesis of RA. In this study, three microarray profiles (GSE55457, GSE55584, and GSE55235) of human joint FLSs from 33 RA patients and 20 normal controls were extracted from the Gene Expression Omnibus Dataset and analyzed to investigate the underlying pathogenesis of RA. As analyzed by the differently expressed genes, gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway enrichment, and protein-protein interaction network analysis, syndecan-4 (SDC4), a receptor of multiple cytokines and chemokines, which played a key role in the regulation of inflammatory response, was found to be an essential regulator in RA. To further validate these results, the levels of SDC4, reactive oxygen species (ROS), nitric oxide (NO), inflammation, and apoptosis in RA-FLSs were examined. SDC4-silenced RA-FLSs were also used. The results demonstrated that SDC4 and the level of ROS, NO, and inflammation were highly expressed while the apoptosis was decreased in RA-FLSs compared with normal FLSs. SDC4 silencing significantly suppressed the levels of ROS, NO, and inflammation; elevated the expression of nuclear factor erythroid 2-related factor 2; and promoted the apoptosis of RA-FLSs. Collectively, our results demonstrated a new mechanism of SDC4 in initiating the inflammation and inhibiting the apoptosis of RA-FLSs and that a potential target for the diagnosis and treatment of RA in the clinic might be developed.     

Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a marker of oxidative stress in rheumatoid arthritis and aging: effect of progressive resistance training

Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG), as a measure of oxidative stress, was measured before and after 12 weeks of progressive resistance strength training in 8 healthy elderly (65–80 yr) and eight healthy young (22–30 yr) men and women, and in eight adults (25–65 yr) with rheumatoid arthritis (RA).Training subjects exercised at 80% of their one-repetition maximum and performed eight repetitions per set, three sets per session, on a twice-weekly basis. 8-OHdG was measured at baseline and follow-up (at least 24 hr after the last exercise session) in the RA and elderly subject groups, and at baseline only in young subjects.Baseline 8-OHdG levels were greater among subjects with RA compared to both healthy young (P < 0.001) and elderly (P < 0.05) subjects. There were no changes in 8-OHdG levels in either RA or elderly subjects as a result of the strength training intervention.These results suggest that subjects with RA have higher levels of oxidative stress than young and elderly healthy individuals. Furthermore, there is no change in oxidative stress, measured by urinary 8-OHdG, in elderly healthy individuals or in subjects with RA after a 12-week strength training intervention.     

Traumatic brain injury and bone healing: radiographic and biomechanical analyses of bone formation and stability in a combined murine trauma model

Introduction:The combination of traumatic brain injury (TBI) and long-bone fractures has previously been reported to lead to exuberant callus formation. The aim of this experimental study was to radiographically and biomechanically study the effect of TBI on bone healing in a mouse model.Materials and methods:138 female C57/Black6N mice were assigned to four groups (fracture (Fx) / TBI / combined trauma (Fx/TBI) / controls). Femoral osteotomy and TBI served as variables: osteotomies were stabilized with external fixators, TBI was induced with controlled cortical impact injury. During an observation period of four weeks, in vivo micro-CT scans of femora were performed on a weekly basis. Biomechanical testing of femora was performed ex vivo.Results:The combined-trauma group showed increased bone volume, higher mineral density, and a higher rate of gap bridging compared to the fracture group. The combined-trauma group showed increased torsional strength at four weeks.Discussion:TBI results in an increased formation of callus and mineral density compared to normal bone healing in mice. This fact combined with a tendency towards accelerated gap bridging leads to increased torsional strength. The present study underscores the empirical clinical evidence that TBI stimulates bone healing. Identification of underlying pathways could lead to new strategies for bone-stimulating approaches in fracture care.     

Role of protein arginine methyltransferase 5 in inflammation and migration of fibroblast‐like synoviocytes in rheumatoid arthritis

To probe the role of protein arginine methyltransferase 5 (PRMT5) in regulating inflammation, cell proliferation, migration and invasion of fibroblast‐like synoviocytes (FLSs) from patients with rheumatoid arthritis (RA). FLSs were separated from synovial tissues (STs) from patients with RA and osteoarthritis (OA). An inhibitor of PRMT5 (EPZ015666) and short interference RNA (siRNA) against PRMT5 were used to inhibit PRMT5 expression. The standard of protein was measured by Western blot or immunofluorescence. The excretion and genetic expression of inflammatory factors were, respectively, estimated by enzyme‐linked immunosorbent assay (ELISA) and real‐time polymerase chain reaction (PCR). Migration and invasion in vitro were detected by Boyden chamber assay. FLSs proliferation was detected by BrdU incorporation. Increased PRMT5 was discovered in STs and FLSs from patients with RA. In RA FLSs, the level of PRMT5 was up‐regulated by stimulation with IL‐1β and TNF‐α. Inhibition of PRMT5 by EPZ015666 and siRNA‐mediated knockdown reduced IL‐6 and IL‐8 production, and proliferation of RA FLSs. In addition, inhibition of PRMT5 decreased in vitro migration and invasion of RA FLSs. Furthermore, EPZ015666 restrained the phosphorylation of IκB kinaseβ and IκBα, as well as nucleus transsituation of p65 as well as AKT in FLSs. PRMT5 regulated the production of inflammatory factors, cell proliferation, migration and invasion of RA FLS, which was mediated by the NF‐κB and AKT pathways. Our data suggested that targeting PRMT5 to prevent synovial inflammation and destruction might be a promising therapy for RA.     

Targeting nanomedicines in the treatment of rheumatoid arthritis: focus on certolizumab pegol

Anti-TNFalpha therapy has revolutionized the treatment of rheumatoid arthritis (RA) and other inflammatory diseases. These drugs are powerful and expensive. A new anti-TNFalpha agent, a nanomolecule comprising a humanized Fab' antibody fragment against TNFalpha with a polyethylene glycol tail, is shortly to complete phase III trials in RA. In this review we will discuss the construct of this new molecule, data from trials so far, and its potential place in the market place.     

Hormone replacement therapy,calcium and vitamin D<Subscript>3</Subscript> versus calcium and vitamin D<Subscript>3</Subscript>alone decreases markers of cartilage and bone metabolism in rheumatoid arthritis: a randomized controlled trial [ISRCTN46523456]

This study aimed to evaluate the effects of hormone replacement therapy (HRT), known to prevent osteoporosis and fractures, on markers of bone and cartilage metabolism. Furthermore, we assessed whether changes in these markers corresponded to alterations in bone mineral density and radiographic joint destructions in postmenopausal women with rheumatoid arthritis. Eighty-eight women were randomized to receive HRT, calcium, and vitamin D3, or calcium and vitamin D3 alone, for 2 years. Bone turnover was studied by analyzing serum levels of C-terminal telopeptide fragments of type I collagen (CTX-I), C-terminal telopeptide of type I collagen (ICTP), bone sialoprotein, and C-terminal propeptide of type I procollagen (PICP) and cartilage turnover by urinary levels of collagen type II C-telopeptide degradation fragments (CTX-II) and cartilage oligomeric matrix protein (COMP) in serum. Treatment with HRT resulted in decrease in CTX-I (P < 0.001), ICTP (P < 0.001), PICP (P < 0.05), COMP (P < 0.01), and CTX-II (P < 0.05) at 2 years. Reductions in CTX-I, ICTP, and PICP were associated with improved bone mineral density. Of the markers tested, CTX-I reflected bone turnover most sensitively; it was reduced by 53 +/- 6% in the patients receiving HRT. Baseline ICTP (P < 0.001), CTX-II (P < 0.01), and COMP (P < 0.05) correlated with the Larsen score. We suggest that biochemical markers of bone and cartilage turnover may provide a useful tool for assessing novel treatment modalities in arthritis, concerning both joint protection and prevention of osteoporosis.     

Comparison of biosimilar CT-P10 and innovator rituximab in patients with rheumatoid arthritis: a randomized controlled Phase 3 trial

This multinational, randomized, double-blind trial, (ClinicalTrials.gov identifier NCT02149121) was designed to demonstrate equivalence in pharmacokinetics and efficacy between CT-P10 and innovator rituximab (RTX) in patients with rheumatoid arthritis (RA). Adults with active RA were treated with CT-P10, United States-sourced RTX (US-RTX; Rituxan®), or European Union-sourced RTX (EU-RTX; MabThera®) at weeks 0 and 2. The co-primary pharmacokinetic endpoints were area under the serum concentration–time curve (AUC) from time zero to last measurable concentration (AUC_0–last), AUC from time zero to infinity (AUC_0–∞), and maximum concentration (C_max) after two infusions. The primary efficacy endpoint was change from baseline to week 24 in Disease Activity Score using 28 joints-C-reactive protein (DAS28-CRP). Pharmacodynamics, immunogenicity, and safety were also assessed. 372 patients were randomly assigned to CT-P10 (n = 161) or RTX (n = 211 [US-RTX, n = 151; EU-RTX, n = 60]). For the co-primary pharmacokinetic endpoints, 90% confidence intervals (CI) for ratios of geometric means (CT-P10/US-RTX, CT-P10/EU-RTX or EU-RTX/US-RTX) all fell within the equivalence margin of 80–125%. Adjusted least squares (LS) mean (standard error) change from baseline in DAS28-CRP at week 24 was ?2.13 (0.175) for CT-P10 and ?2.09 (0.176) for RTX. The 95% CI (?0.29, 0.21) of the estimated treatment difference between CT-P10 and RTX (?0.04) was entirely within the efficacy equivalence margin of ±0.5. Pharmacodynamics, immunogenicity, and safety profiles were similar for CT-P10 and RTX. The pharmacokinetics of CT-P10, US-RTX, and EU-RTX were equivalent. CT-P10 and RTX were also equivalent in terms of efficacy and displayed similar pharmacodynamic, immunogenicity, and safety profiles up to week 24.     

Effect of rapamycin on bone mass and strength in the α2(I)‐G610C mouse model of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is commonly caused by heterozygous type I collagen structural mutations that disturb triple helix folding and integrity. This mutant‐containing misfolded collagen accumulates in the endoplasmic reticulum (ER) and induces a form of ER stress associated with negative effects on osteoblast differentiation and maturation. Therapeutic induction of autophagy to degrade the mutant collagens could therefore be useful in ameliorating the ER stress and deleterious downstream consequences. To test this, we treated a mouse model of mild to moderate OI (α2(I) G610C) with dietary rapamycin from 3 to 8 weeks of age and effects on bone mass and mechanical properties were determined. OI bone mass and mechanics were, as previously reported, compromised compared to WT. While rapamycin treatment improved the trabecular parameters of WT and OI bones, the biomechanical deficits of OI bones were not rescued. Importantly, we show that rapamycin treatment suppressed the longitudinal and transverse growth of OI, but not WT, long bones. Our work demonstrates that dietary rapamycin offers no clinical benefit in this OI model and furthermore, the impact of rapamycin on OI bone growth could exacerbate the clinical consequences during periods of active bone growth in patients with OI caused by collagen misfolding mutations.