Association of baseline levels of markers of bone and cartilage degradation with long-term progression of joint damage in patients with early rheumatoid arthritis: the COBRA study

A new serum biochemical marker of synovium turnover predicts radiographic progression in patients with early arthritis

OBJECTIVE

To investigate whether serum Col 3-4, a new biochemical marker of synovial tissue turnover, was associated with progression of joint damage in patients with early arthritis.

METHODS

A total of 788 early arthritis patients (<6 months of symptoms, 82% diagnosis of RA, 18% undifferentiated arthritis) from the prospective ESPOIR study were investigated. Progression was defined as an increase of 1 or 5 unit(s) in radiographic van der Heijde modified Sharp score between baseline and 1 or 5 years, respectively. Associations between baseline Col 3-4 and progression were assessed by logistic regression.

RESULTS

Each standard deviation increase of baseline Col 3-4 levels was associated with an increased 5-yr total damage progression with an odds ratio (OR, 95% CI) of 1.51 (1.21, 1.88), which remained significant when DAS28, C-reactive protein and anti-citrullinated protein antibodies positivity were included in the model [OR (95% CI): 1.34 (1.01, 1.76)]. Further adjustment for bone erosion did not modify the association. Patients with both Col 3-4 in the highest quintile and bone erosion had a >2-fold higher risk of progression [OR (95% CI): 7.16 (2.31, 22)] than patients with either high Col 3-4 [2.91 (1.79, 4.73)] or bone erosion [2.36 (2.38, 3.70)] alone. Similar associations were observed for prediction of 12 months progression.

CONCLUSIONS

Increased serum Col 3-4 is associated with a higher risk of structural progression, independently of major risk factors. Col 3-4 may be useful in association with bone erosion to identify patients with early arthritis at higher risk.

Advances in bone turnover markers

Bone fragility fractures remain an important worldwide health and economic problem due to increased morbidity and mortality. The current methods for predicting fractures are largely based on the measurement of bone mineral density and the utilization of mathematical risk calculators based on clinical risk factors for bone fragility. Despite these approaches, many bone fractures remain undiagnosed. Therefore, current research is focused on the identification of new factors such as bone turnover markers (BTM) for risk calculation. BTM are a group of proteins and peptides released during bone remodeling that can be found in serum or urine. They derive from bone resorptive and formative processes mediated by osteoclasts and osteoblasts, respectively. Potential use of BTM in monitoring these phenomenon and therefore bone fracture risk is limited by physiologic and pathophysiologic factors that influence BTM. These limitations in predicting fractures explain why their inclusion in clinical guidelines remains limited despite the large number of studies examining BTM.

Bone Metabolism and RANKL/OPG Ratio in Rheumatoid Arthritis Women Treated with TNF-α Inhibitors

The aim of this study was to evaluate the effect of anti-tumor necrosis factor α (anti-TNF-α) therapy in combination with methotrexate on bone remodeling and osteoclastogenesis in female patients with RA. Serum levels of bone turnover markers (i.e., C- and N-terminal propeptides of type I procollagen (PICP and PINP), C- and N-terminal cross-linking telopeptides of type I collagen (CTX-I and NTX-I), and soluble receptor activator of nuclear factor κB ligand (sRANKL) and osteoprotegerin (OPG)) were determined by immunoassay at baseline and 15 months after initiation of treatment. Bone mineral density was measured by dual-energy x-ray absorptiometry. We found a significant decrease in serum PINP levels, a biomarker of bone formation, and higher levels of CTX-I and sRANKL indicative of increased bone resorption in RA patients prior to TNFαI treatment compared to the controls. Anti-TNF-α therapy was effective in improving bone metabolism in RA patients as reflected in a decrease in CTX-I (at least partially due to the RANKL/OPG reduction) and a concomitant increase in PINP levels. The bone metabolism changes were independent of the type of TNFαI used. PINP and CTX-I were found to be useful markers of bone metabolism, which may prove the effectiveness of TNF-α therapy earlier than the bone density assessment.

Biomarkers in Rheumatoid Arthritis

The utilization and identification of biomarkers in rheumatoid arthritis (RA) to facilitate timely diagnosis and the optimal management of the disease is an area of active investigation. This review focuses on biomarkers available for routine clinical use, details potential investigational biomarkers, and raises outstanding clinical questions.

Bone phenotypes in rheumatology - there is more to bone than just bone

Osteoarthritis, rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis, all have one clear common denominator; an altered turnover of bone. However, this may be more complex than a simple change in bone matrix and mineral turnover. While these diseases share a common tissue axis, their manifestations in the area of pathology are highly diverse, ranging from sclerosis to erosion of bone in different regions. The management of these diseases will benefit from a deeper understanding of the local versus systemic effects, the relation to the equilibrium of the bone balance (i.e., bone formation versus bone resorption), and the physiological and pathophysiological phenotypes of the cells involved (e.g., osteoblasts, osteoclasts, osteocytes and chondrocytes). For example, the process of endochondral bone formation in chondrocytes occurs exists during skeletal development and healthy conditions, but also in pathological conditions. This review focuses on the complex molecular and cellular taxonomy of bone in the context of rheumatological diseases that alter bone matrix composition and maintenance, giving rise to different bone turnover phenotypes, and how biomarkers (biochemical markers) can be applied to potentially describe specific bone phenotypic tissue profiles.

3D gait analysis, haemophilia joint health score, leg muscle laterality and biomarkers of joint damage: A cross-sectional comparative assessment of haemophilic arthropathy

Introduction

3D gait analysis has been proposed as a reproducible and valid method to assess abnormal gait patterns and to monitor disease progression in patients with haemophilia (PWH).

Aim

This study aimed at comparing Gait Deviation Index (GDI) between adult PWH and healthy controls, and at assessing the agreement between outcome measures of haemophilic arthropathy.

Methods

Male PWH aged 18‐49 years (prespecified subgroups: 18‐25 vs 26‐49 years) on prophylactic replacement therapy, and male healthy age‐matched controls passed through a cross‐sectional assessment panel. Besides the 3D gait analysis derived GDI, secondary outcomes included kinematic, kinetic and spatio‐temporal gait parameters, the Haemophilia Joint Health Score (HJHS), electric impedance derived leg muscle laterality and inflammatory biomarkers.

Results

Patients with haemophilia (n = 18) walked slower, in shorter steps and accordingly with less functional range of motion in the hips and ankles, as compared to healthy controls (n = 24). Overall, PWH did not differ significantly in GDI and specific gait parameters. PWH had a higher mean HJHS (18.8 vs 2.6, P = .000) and leg muscle laterality (4.3% vs 1.5%, P = .004). A subgroup analysis revealed progressed gait pathology in PWH aged 26‐49 years (not statistically significant). Leg muscle laterality was strongly correlated with HJHS (r = .76, P = .000), whereas GDI just moderately (r = −.39, P = .110). PWH had higher levels of the inflammatory markers CRP and IL‐6.

Conclusion

Progressed gait pathology was found in PWH, mainly those aged 26‐49 years. Leg muscle laterality correlated strongly with HJHS and was identified as a promising tool for detecting progression and physiological consequences of haemophilic joint arthropathy.

Effects of intra-articular pulsed radiofrequency current administration on a rabbit model of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovial proliferation and inflammation. Intra-articular corticosteroid injections are commonly used for the treatment of arthritis affecting one or two joints. Although corticosteroid injections are fast-acting, repeated usage can result in severe adverse events. Recently, intra-articular pulsed radiofrequency (PRF) stimulation has been proposed to treat arthritis. The aim of the present study was to compare the effectiveness of intra-articular PRF with corticosteroid injection based on histopathological and motion analysis of an ovalbumin (OVA)-induced RA rabbit model. RA was induced in the right knee joint of 18 rabbits via OVA injection. The rabbits were randomly allocated into a PRF, an intra-articular corticosteroid injection or a sham PRF stimulation group. Movement was assessed in the rabbits before treatment, then at 2, 4 and 8 weeks after treatment using walking distance, fast walking time and mean walking speed. Histopathological evaluation of the distal femur and synovium was conducted 2, 4 and 8 weeks after treatment. Motion analysis demonstrated that changes in all movement variables showed significant group and time interaction as well as group effect among the three groups. The semiquantitative score based on the histopathological findings for the distal femoral condyle decreased 2 and 4 weeks after both the PRF and steroid groups, compared with the sham PRF group. Moreover, in the synovium, the semiquantitative histological score in the PRF and steroid groups tended to be lower compared with the sham PRF group, although this result was not statistically significant. Thus, intra-articular PRF stimulation may delay cartilage destruction and improve functional motion in RA.

The role of biochemical markers of joint tissue remodelling to predict progression and treatment efficacy in inflammatory rheumatic diseases

Structural damage is a hallmark in RA, spondyloarthropy (SpA) and psoriatric arthritis (PsA). Its progression is difficult to predict and current radiological or inflammatory biological markers lack sensitivity. Biochemical markers of bone, cartilage and synovial tissues provide a dynamic indication of the anabolism and catabolism of joint tissues and can be easily measured by immunoassays. Novel biochemical markers including post-translational modifications of matrix proteins and enzyme-generated neoepitopes with increased tissue and/or biological pathway specificity have been developed. Their evaluation in clinical trials of novel biologic therapies and epidemiological studies indicated that their measurements could be useful to predict progression of structural damage and treatment efficacy, independently of current clinical, radiological and biological indices of disease activity. In this paper we briefly describe the latest developments in biochemical markers and critically analyse the clinical data assessing the utility of established and novel biochemical markers in RA, SpA and PsA.

Outcomes and Findings of the International Rheumatoid Arthritis (RA) BIODAM Cohort for Validation of Soluble Biomarkers in RA

OBJECTIVE

The Outcome Measures in Rheumatology Soluble Biomarker Working Group initiated an international, multicenter, prospective study, the Rheumatoid Arthritis (RA) BIODAM cohort, to generate resources for the clinical validation of candidate biomarkers predictive of radiographic progression. This first report describes the cohort, clinical outcomes, and radiographic findings.

METHODS

Patients with RA from 38 sites in 10 countries starting or changing conventional synthetic disease-modifying antirheumatic drugs and/or starting tumor necrosis factor inhibitors were followed for 2 years. Participating physicians were required to adhere to a treat-to-target strategy. Biosamples (serum, urine) were acquired every 3 months, radiography of hands and feet every 6 months, and ultrasound of hands and feet every 3 months in a subset. Primary endpoint was radiographic progression by the Sharp/van der Heijde score.

RESULTS

A total of 571 patients were recruited and 439 (76.9%) completed 2-year followup. At baseline, the majority was female (76%), mean age 55.7 years, and mean disease duration 6.5 years. Patients had a mean of 8.4 swollen and 13.6 tender joints, 44-joint count Disease Activity Score (DAS44) 3.8, 77.7% rheumatoid factor-positive or anticitrullinated protein antibody-positive. Percentage of patients in DAS and American College of Rheumatology remission at 2 years was 52.2% and 27.1%, respectively. Percentage of patients with radiographic progression (> 0.5) at 1 and 2 years was 38.2% and 59.9%, respectively.

CONCLUSION

The RA BIODAM prospective study succeeded in generating an extensive list of clinical, imaging (2343 radiographs), and biosample (4638 sera) resources that will be made available to expedite the identification and validation of biomarkers for radiographic damage endpoints. (Clinicaltrials.gov: NCT01476956, clinicaltrials.gov/ct2/show/NCT01476956).

GPDPLQ1237-A Type II Collagen Neo-Epitope Biomarker of Osteoclast- and Inflammation-Derived Cartilage Degradation in vitro

C-telopeptide of type II collagen (CTX-II) has been shown to be a highly relevant biomarker of cartilage degradation in human rheumatic diseases, if measured in synovial fluid or urine. However, serum or plasma CTX-II have not been demonstrated to have any clinical utility to date. Here, we describe the GPDPLQ₁₂₃₇ ELISA which targets the EKGPDPLQ↓ neo-epitope, an elongated version of the CTX-II neo-epitope (EKGPDP↓), speculated to be a blood-precursor of CTX-II generated by the cysteine protease cathepsin K. Human osteoclast cartilage resorption cultures as well as oncostatin M and tumour necrosis factor α-stimulated bovine cartilage explant cultures were used to validate GPDPLQ₁₂₃₇ biologically by treating the cultures with the cysteine protease inhibitor E-64 and/or the matrix metalloproteinase (MMP) inhibitor GM6001 to assess the potential contributions of these two protease classes to GPDPLQ₁₂₃₇ release. Cartilage resorption-derived GPDPLQ₁₂₃₇ release was inhibited by E-64 (72.1% inhibition), GM6001 (75.5%), and E-64/GM6001 (91.5%), whereas CTX-II release was inhibited by GM6001 (87.0%) but not by E-64 (5.5%). Cartilage explant GPDPLQ₁₂₃₇ and CTX-II release were both fully inhibited by GM6001 but were not inhibited by E-64. No clinically relevant GPDPLQ₁₂₃₇ reactivity was identified in human serum, plasma, or urine from healthy donors or arthritis patients. In conclusion, the GPDPLQ₁₂₃₇ biomarker is released during osteoclast-derived cysteine protease- and MMP-mediated cartilage degradation in vitro, whereas CTX-II release is mediated by MMPs and not by cysteine proteases, as well as from MMP-mediated cartilage degradation under a pro-inflammatory stimulus. These findings suggest that GPDPLQ₁₂₃₇ may be relevant in diseases with pathological osteoclast activity and cartilage degradation. Further studies are required to validate the neo-epitope in human samples.

Effects of the Cathepsin K Inhibitor ONO-5334 and Concomitant Use of ONO-5334 with Methotrexate on Collagen-Induced Arthritis in Cynomolgus Monkeys

We examined whether the cathepsin K inhibitor, ONO-5334, administered alone or in combination with methotrexate (MTX), could ameliorate joint destruction evoked by collagen-induced arthritis (CIA) in female cynomolgus monkeys. CIA was induced by immunizing with bovine type II collagen. ONO-5334 (30 mg/kg/day) was orally administered once daily and MTX (10 mg/body/day) twice weekly for 9 weeks. X-ray (evaluation of joint destruction) and swelling (inflammatory) scores of proximal interphalangeal (PIP), distal interphalangeal (DIP), and metacarpophalangeal (MP) joints were evaluated. Urinary concentrations of C-terminal telopeptide of type I collagen (CTX-I) and type II collagen (CTX-II) were measured. Arthritis, accompanied by bone and cartilage destruction, was successfully induced in this collagen-induced arthritis monkey model. ONO-5334 showed no suppressive effect on joint swelling, while the joint swelling scores in the MTX and combination (ONO-5334 + MTX) groups were less than 50% compared with the control group. ONO-5334 decreased X-ray score by a mean of 64% (p<0.05 vs the control group), and MTX also decreased in X-ray score by a mean of 46% but with no statistical significance. Combination of ONO-5334 and MTX further decreased the X-ray score by 28% over MTX group (74% reduction vs the control group, p<0.01). Maximum increase in CTX-I (10-fold) and CTX-II (7-fold) compared to baseline was observed at 7 and 3 weeks after the first sensitization, respectively. After treatment with ONO-5334 alone or in combination with MTX, concentrations were maintained near baseline for both markers. In conclusion, ONO-5334 prevented joint destruction but not joint inflammation in this monkey CIA model. Concomitant use of ONO-5334 with MTX reduced architectural joint destruction compared to MTX alone; therefore, ONO-5334 may help to prevent joint destruction in combination with MTX for the treatment of rheumatoid arthritis.

A cross sectional study of bone and cartilage biomarkers: correlation with structural damage in rheumatoid arthritis

The aim of our study was to assess the relationship between bone and cartilage remodeling biomarkers and joint damage in Rheumatoid Arthritis (RA), and to detect whether they have the capacity to predict the progression of joint disease assessment by computed tomography (CT) erosion score. We analyzed 65 female patients with established RA in our Rheumatology Department. Serum levels of bone and cartilage markers were measured: osteocalcin (OC), N-propeptide of type I collagen (PINP), collagen type I and II, C-telopeptide (CTX I, CTX-II) and cartilage oligomeric matrix protein (COMP). Radiography of both wrist and MCP joints were available. Two expert-readers independently scored articular damage and progression using the High-resolution low dose CT scan in a blinded fashion. 65 female patients with established RA with a median age of 44 years were included. The median disease-duration was two years and the median (Disease activity score) DAS 28 score at 4.46 [2.65-7.36]. The percentage of patient with low disease activity was 13.8%, while 55.4 and 30.8% for those with moderate and high disease activity respectively. The resorption bone markers were high in active versus non-active RA. Wrist and MCP erosion scores were also associated with RA activity. Our study shows that biomarkers of bone and cartilage collagen breakdown were related to specific joint erosion in RA and could predict subsequent radiographic damage in RA. Further larger scale longitudinal studies maybe needed to confirm our data.

Serum N-propeptide of collagen IIA (PIIANP) as a marker of radiographic osteoarthritis burden

OBJECTIVE

Cartilage homeostasis relies on a balance of catabolism and anabolism of cartilage matrix. Our goal was to evaluate the burden of radiographic osteoarthritis and serum levels of type IIA procollagen amino terminal propeptide (sPIIANP), a biomarker representing type II collagen synthesis, in osteoarthritis.

METHODS

OA burden was quantified on the basis of radiographic features as total joint faces with an osteophyte, joint space narrowing, or in the spine, disc space narrowing. sPIIANP was measured in 1,235 participants from the Genetics of Generalized Osteoarthritis study using a competitive enzyme-linked immunosorbent assay. Separate multivariable linear regression models, adjusted for age, sex, and body mass index and additionally for ipsilateral osteophytes or joint/disc space narrowing, were used to assess the independent association of sPIIANP with osteophytes and with joint/disc space narrowing burden in knees, hips, hands and spine, individually and together.

RESULTS

After full adjustment, sPIIANP was significantly associated with a lesser burden of hip joint space narrowing and knee osteophytes. sPIIANP was associated with a lesser burden of hand joint space narrowing but a greater burden of hand osteophytes; these results were only evident upon adjustment for osteoarthritic features in all other joints. There were no associations of sPIIANP and features of spine osteoarthritis.

CONCLUSIONS

Higher cartilage collagen synthesis, as reflected in systemic PIIANP concentrations, was associated with lesser burden of osteoarthritic features in lower extremity joints (knees and hips), even accounting for osteoarthritis burden in hands and spine, age, sex and body mass index. These results suggest that pro-anabolic agents may be appropriate for early treatment to prevent severe lower extremity large joint osteoarthritis.

Measuring clinically relevant endpoints in a serum-free, three-dimensional, primary cell culture system of human osteoarthritic articular chondrocytes

Osteoarthritis (OA) is characterized by degeneration of articular cartilage within the joint, inflammation and pain. The purpose of this study was to develop a primary, serum free cell culture system of human osteoarthritic articular chondrocytes (HOACs) with which to study manifestations of the disease process. Joint tissues were obtained from OA patients undergoing total knee arthroplasty (TKA). HOACs isolated from the femoral condyles and tibial plateau of the same side were combined, plated in three-dimensional, alginate beads and cultured for five days in serum, hormone and protein free medium. More living cells were obtained from the femoral condyles than the tibial plateau. The optimal plating density was 2.5 × 10⁶ cells/ml of alginate. The amounts of DNA, RNA, proteoglycans and total collagen were similar in cultures prepared from the sides of least and greatest pathology. More type 1 than type 2 collagen was detected in the medium on days 2 and 5. A greater percentage of type 1 than type 2 collagen was degraded. The inflammatory cytokine interleukin-1 beta was present in the medium and alginate associated matrix. Although variation in the metabolic profiles between subjects was observed, HOACs from all patients continued to reflect the OA phenotype for five days in culture. This serum free, three-dimensional primary culture system of HOACs provides a platform with which to measure clinically relevant endpoints of OA and screen potential disease modifying OA therapeutics.

Development and validation of novel biomarker assays for osteoarthritis

Background

Osteoarthritis (OA) is the most common chronic joint disease usually diagnosed at relatively advanced stages when there is irreparable damage to the joint(s). Recently, we have identified two novel biomarkers C3f and V65 which appear to be OA-specific and therefore potential markers of early disease. We report the development of immunoassays for quantitative measure of these two novel biomarkers.

Method

Monoclonal and polyclonal antibodies were generated by immunising mouse and rabbits respectively with peptide-carrier conjugates of C3f and V65. Affinity purified antibodies were used for immunoassays development and assays validated using serum from OA patients and controls.

Results

The ELISAs developed showed spiked recovery of up to 96% for C3f and V65 peptides depending on serum dilutions with a coefficient of variation (CV) <10%. The intra- and inter-assay CVs for C3f and V65 were 1.3–10.8% and 4.2–10.3% respectively. Both assays were insensitive for measurements of the peptides in patients and the use of different signal amplification systems did not increase assay sensitivity.

Conclusion

We have developed two immunoassays for measurements of C3f and V65 peptides biomarkers discovered by our earlier proteomic study. These assays could detect the endogenous peptides in serum samples from patients and controls but lacked sensitivity for accurate measurements of the peptides in patients. Our study highlights the difficulties and challenges of validating biomarker from proteomic studies and demonstrates how to overcome some of the technical challenges associated with developing immunoassays for small peptides.

Defining the proteomic landscape of rheumatoid arthritis: progress and prospective clinical applications

INTRODUCTION

The heterogeneity of Rheumatoid Arthritis (RA) and the absence of clinical tests accurate enough to identify the early stages of this disease have hampered its management. Therefore, proteomics research is increasingly focused on the discovery of novel biological markers, which would not only be able make an early diagnosis, but also to gain insight into the different pathological mechanisms underlying the heterogeneity of RA and also to stratify patients, which is critical to enabling effective treatments. Areas covered: The proteomic approaches that have been utilised to provide knowledge about RA pathogenesis, and to identify biomarkers for RA diagnosis, prognosis, disease monitoring and prediction of response to therapy, are summarized. Expert commentary: Although each proteomic study is unique in its design, all of them have contributed to the understanding of RA pathogenesis and the discovery of promising biomarkers for patient stratification, which would improve clinical care of RA patients. Still, efforts need to be made to validate these findings and translate them into clinical practice.

Biologic therapies and bone loss in rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a common systemic autoimmune disease of unknown cause, characterized by a chronic, symmetric, and progressive inflammatory polyarthritis. One of the most deleterious effects induced by the chronic inflammation of RA is bone loss. During the last 15 years, the better knowledge of the cytokine network involved in RA allowed the development of potent inhibitors of the inflammatory process classified as biological DMARDs. These new drugs are very effective in the inhibition of inflammation, but there are only few studies regarding their role in bone protection. The principal aim of this review was to show the evidence of the principal biologic therapies and bone loss in RA, focusing on their effects on bone mineral density, bone turnover markers, and fragility fractures.

METHODS

Using the PICOST methodology, two coauthors (PC, LM-S) conducted the search using the following MESH terms: rheumatoid arthritis, osteoporosis, clinical trials, TNF- antagonists, infliximab, adalimumab, etanercept, certolizumab, golimumab, IL-6 antagonists, IL-1 antagonists, abatacept, tocilizumab, rituximab, bone mineral density, bone markers, and fractures. The search was conducted electronically and manually from the following databases: Medline and Science Direct. The search period included articles from 2003 to 2015. The selection included only original adult human research written in English. Titles were retrieved and the same two authors independently selected the relevant studies for a full text. The retrieved selected studies were also reviewed completing the search for relevant articles. The first search included 904 titles from which 253 titles were selected. The agreement on the selection among researchers resulted in a Kappa statistic of 0.95 (p < 0.000). Only 248 abstracts evaluated were included in the acronym PICOST. The final selection included only 28 studies, derived from the systematic search. Additionally, a manual search in the bibliography of the selected articles was made and included into the text and into the section of "small molecules of new agents."

CONCLUSION

Treatment with biologic drugs is associated with the decrease in bone loss. Studies with anti-TNF blocking agents show preservation or increase in spine and hip BMD and also a better profile of bone markers. Most of these studies were performed with infliximab. Only three epidemiological studies analyzed the effect on fractures after anti-TNF blocking agent's treatment. IL-6 blocking agents also showed improvement in localized bone loss not seen with anti-TNF agents. There are a few studies with rituximab and abatacept. Although several studies reported favorable actions of biologic therapies on bone protection, there are still unmet needs for studies regarding their actions on the risk of bone fractures.

Bone Turnover Markers in the Diagnosis and Monitoring of Metabolic Bone Disease

BACKGROUND

Disorders of bone metabolism, most notably osteoporosis, are highly prevalent and predispose to fractures, causing high patient morbidity and mortality. Diagnosis and monitoring of bone metabolic defects can present a major challenge as these disorders are largely asymptomatic and radiographic measures of bone mass respond slowly to changes in bone physiology.

CONTENT

Bone turnover markers (BTMs) are a series of protein or protein derivative biomarkers released during bone remodeling by osteoblasts or osteoclasts. BTMs can offer prognostic information on fracture risk that supplements radiographic measures of bone mass, but testing using BTMs has to take into account the large number of preanalytic factors and comorbid clinical conditions influencing BTM levels. BTMs respond rapidly to changes in bone physiology, therefore, they have utility in determining patient response to and compliance with therapies for osteoporosis.

SUMMARY

BTMs are a useful adjunct for the diagnosis and therapeutic monitoring of bone metabolic disorders, but their use has to be tempered by the known limitations in their clinical utility and preanalytic variables complicating interpretation.

Boron neutron capture synovectomy (BNCS) as a potential therapy for rheumatoid arthritis: radiobiological studies at RA-1 Nuclear Reactor in a model of antigen-induced arthritis in rabbits

Rheumatoid arthritis is a chronic autoimmune pathology characterized by the proliferation and inflammation of the synovium. Boron neutron capture synovectomy (BNCS), a binary treatment modality that combines the preferential incorporation of boron carriers to target tissue and neutron irradiation, was proposed to treat the pathological synovium in arthritis. In a previous biodistribution study, we showed the incorporation of therapeutically useful boron concentrations to the pathological synovium in a model of antigen-induced arthritis (AIA) in rabbits, employing two boron compounds approved for their use in humans, i.e., decahydrodecaborate (GB-10) and boronophenylalanine (BPA). The aim of the present study was to perform low-dose BNCS studies at the RA-1 Nuclear Reactor in the same model. Neutron irradiation was performed post intra-articular administration of BPA or GB-10 to deliver 2.4 or 3.9 Gy, respectively, to synovium (BNCS-AIA). AIA and healthy animals (no AIA) were used as controls. The animals were followed clinically for 2 months. At that time, biochemical, magnetic resonance imaging (MRI) and histological studies were performed. BNCS-AIA animals did not show any toxic effects, swelling or pain on palpation. In BNCS-AIA, the post-treatment levels of TNF-α decreased in four of six rabbits and IFN-γ levels decreased in five of six rabbits. In all cases, MRI images of the knee joint in BNCS-AIA resembled those of no AIA, with no necrosis or periarticular effusion. Synovial membranes of BNCS-AIA were histologically similar to no AIA. BPA-BNCS and GB-10-BNCS, even at low doses, would be therapeutically useful for the local treatment of rheumatoid arthritis.

The effects of dopamine receptor 2 expression on B cells on bone metabolism and TNF-α levels in rheumatoid arthritis

Background

Dopamine receptor 2 (DR2) expressions on B cells from Rheumatoid arthritis (RA) patients has been found to be negatively correlated with disease activity and can potentially predict the response to treatment. This study aimed to investigate the role of B cell DR2 expression on bone remodeling in RA.

Methods

Patients with RA (n = 14) or osteoarthritis (OA; n = 12), and healthy controls (n = 12) were recruited for this study. Dopamine receptor (DR) 2 expression was assessed using flow cytometry. Pro-inflammatory cytokines, including interleuin(IL)-1β, IL-6, IL-17, and tumor necrosis factor(TNF)-α, and bone turnovers, including osteocalcin (OC),serum procollagen type I N propeptide (PINP), C-terminal telopeptide of type I collagen (β-CTX), collagen type I cross-linked telopeptide (ICTP), as well as matrix metalloproteinase-3 (MMP-3) and osteoprotegerin (OPG) were measured by electrochemiluminescence, chemiluminescence, or enzyme-linked immunosorbent assay. DR2 expression on synovial B cells from 4 RA patients and 3 OA patients was detected by immunofluorescence.

Results

There were more DR2⁺CD19⁺ B cells in synovial tissues from RA patients than in those from OA patients. The frequency of peripheral B cells that expressed DR2 was positively correlated with plasma TNF-α level. Levels of ICTP and MMP-3 were significantly higher, and OPG were lower in RA patients compared to those in the OA group and healthy controls (all P < 0.05).

Conclusion

The frequency of B cells that expressed DR2 showed a correlation with levels of the pro-inflammatory cytokine TNF-α. DR2⁺CD19⁺ B cells in synovial tissues might have a role in bone metabolism and TNF-α production.

Effect of mud compress therapy on cartilage destruction detected by CTX-II in patients with knee osteoarthritis

BACKGROUND/OBJECTIVE

The aim of this study is to investigate the effect of mud compress (MC) therapy compared to hot pack (HP) therapy on cartilage destruction and subchondral bone alterations detected by urine levels of C telopeptide fragment of collagen type-II (uCTX-II) in patients with knee osteoarthritis (OA).

METHODS

Fifty-nine patients between 49-74 years of age with bilateral knee OA divided into 2 groups. Twenty-five patients (16 females, 9 males) and 34 patients (22 females, 13 males) were given HP versus local natural organic and mineral-rich MC therapy respectively for 2 weeks as a total of 12 sessions. uCTX-II, Visual Analog Scale (VAS), 15 m walking time, Western Ontario and McMaster Universities multifunctional (WOMAC) index were measured at baseline, after-treatment and 3 months after treatment.

RESULTS

uCTX-II level did not show any difference between the two groups, however it decreased significantly in MC and HP groups 3 months after treatment (p< 0.017). WOMAC stiffness sore was significantly lower in MC group 3 months after treatment (p< 0.05). Both MC and HP therapies lowered VAS, WOMAC total and subscores significantly up to 3 months (p< 0.017).

CONCLUSIONS

HP and MC therapies for OA of knee are not superior to one another with respect to the level of uCTX-II. MC may probably decrease the ongoing cartilage destruction and related subchonral bone interactions earlier compared to HP treatment in patients with knee OA as evidenced by decreased uCTX-II levels after-treatment.

Osteopontin as a biochemical marker and severity indicator for idiopathic hip osteoarthritis

INTRODUCTION

A diagnostic evaluation of the severity and progression of hip osteoarthritis (OA) using biochemical markers is lacking in the current medical literature. Osteopontin (OPN) has been proved to correlate with the progression and severity of knee OA. Therefore, the examination of plasma OPN levels in patients with idiopathic hip OA and its correlation with disease severity and progression was necessary.

METHODS

Our study included 21 patients displaying symptomatic severe idiopathic hip OA; the diagnosis of the disease was based on the checklist of the American College of Rheumatology and the severity was evaluated according to the K-L grading (Kellgran and Lawrence score).

RESULTS

14 patients showed radiological changes according K-L grade 3 (66.66%), and 7 patients showed radiological changes according K-L grade 4 (33.33%). We observed a highly statistically significant increase of plasma OPN levels in comparison with normal referenced values, the cut off value for differentiating between normal people and patients with hip OA was 193.6 ng/ml. Furthermore, the mean of plasma OPN levels in idiopathic hip osteoarthritis patients with K-L grade 4 (362.51 ± 83.31 ng/mL) was greater than those with K-L grade 3 (283.41 ± 56.31 ng/mL), the difference being statistically significant.

CONCLUSIONS

plasma OPN levels are increased in idiopathic hip OA and are correlated with the severity of the disease.

Association of a multibiomarker disease activity score at multiple time-points with radiographic progression in rheumatoid arthritis: results from the SWEFOT trial

OBJECTIVES

In rheumatoid arthritis (RA), predictive biomarkers for subsequent radiographic progression (RP) could improve therapeutic choices for individual patients. We previously showed that the multibiomarker disease activity (MBDA) score in patients with newly diagnosed RA identified patients at risk for RP. We evaluated the MBDA score at multiple time-points as a predictor of RP during 2 years of follow-up.

METHODS

A subset of patients with RA (N=220) from the Swedish Farmacotherapy (SWEFOT) trial were analysed for MBDA score, disease activity score of 28 joints (DAS28), C reactive protein (CRP) and erythrocyte sedimentation rate (ESR) at baseline (BL), month 3 and year 1, for predicting RP based on modified Sharp/van der Heijde scores at BL, year 1 and year 2.

RESULTS

Patients with persistently low MBDA (<30) scores or those with a decrease from moderate (30-44) to low MBDA scores, did not develop RP during 2 years of follow-up. The highest risk for RP during 2 years of follow-up (42%) was observed among patients with persistently high (>44) MBDA scores. Among methotrexate non-responders with a high MBDA score at BL or month 3, significantly more of those who received triple therapy had RP at year 2 compared with those who received antitumour necrosis factor therapy.

CONCLUSIONS

Measuring the MBDA score both before and during treatment in RA was useful for the assessment of individual patient risk for RP during 2 years of follow-up. In comparison with low CRP, ESR or DAS28, a low MBDA score at any time-point was associated with numerically lower proportions of RP.

TRIAL REGISTRATION NUMBER

NCT00764725.

Inflammatory signaling induced bone loss

A broad spectrum of inflammatory disorders have the capacity to target the skeleton and to de-regulate the processes of physiological bone remodeling. This review will focus on the systemic inflammatory rheumatologic disorders, which target articular and peri-articular bone tissues. Many of these disorders also affect extra-articular tissues and organs, and in addition, have the capacity to produce systemic bone loss and increased risk of osteoporotic fractures. Attention will focus on rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and the seronegative spondyloarthropathies (SpAs), which include ankylosing spondylitis (AS), reactive arthritis (formerly designated as Reiter's syndrome), the arthritis of inflammatory bowel disease, juvenile onset spondyloarthropathy and psoriatic arthritis. The discussion will principally focus on RA, which is a prototypical model of an inflammatory disorder that de-regulates bone remodeling, but also will review the other forms of inflammatory joint disease to highlight the differential effects of inflammation on bone remodeling in these conditions. This article is part of a Special Issue entitled "Muscle Bone Interactions".

Early biomarkers of joint damage in rheumatoid and psoriatic arthritis

Joint destruction, as evidenced by radiographic findings, is a significant problem for patients suffering from rheumatoid arthritis and psoriatic arthritis. Inherently irreversible and frequently progressive, the process of joint damage begins at and even before the clinical onset of disease. However, rheumatoid and psoriatic arthropathies are heterogeneous in nature and not all patients progress to joint damage. It is therefore important to identify patients susceptible to joint destruction in order to initiate more aggressive treatment as soon as possible and thereby potentially prevent irreversible joint damage. At the same time, the high cost and potential side effects associated with aggressive treatment mean it is also important not to over treat patients and especially those who, even if left untreated, would not progress to joint destruction. It is therefore clear that a protein biomarker signature that could predict joint damage at an early stage would support more informed clinical decisions on the most appropriate treatment regimens for individual patients. Although many candidate biomarkers for rheumatoid and psoriatic arthritis have been reported in the literature, relatively few have reached clinical use and as a consequence the number of prognostic biomarkers used in rheumatology has remained relatively static for several years. It has become evident that a significant challenge in the transition of biomarker candidates to clinical diagnostic assays lies in the development of suitably robust biomarker assays, especially multiplexed assays, and their clinical validation in appropriate patient sample cohorts. Recent developments in mass spectrometry-based targeted quantitative protein measurements have transformed our ability to rapidly develop multiplexed protein biomarker assays. These advances are likely to have a significant impact on the validation of biomarkers in the future. In this review, we have comprehensively compiled a list of candidate biomarkers in rheumatoid and psoriatic arthritis, evaluated the evidence for their potential as biomarkers of bone (joint) damage, and outlined how mass spectrometry-based targeted and multiplexed measurement of candidate biomarker proteins is likely to accelerate their clinical validation and the development of clinical diagnostic tests.

Initial high-dose prednisolone combination therapy using COBRA and COBRA-light in early rheumatoid arthritis

Treatment with initial high-dose prednisolone and a combination of methotrexate (MTX) and sulfasalazine (SSZ) according to the COBRA regimen (Dutch acronym for combinatietherapie bij reumatoide artritis, 'combination therapy for rheumatoid arthritis'), has repeatedly been demonstrated to be very effective in early rheumatoid arthritis (RA). COBRA combination therapy is superior to initial monotherapy of SSZ and MTX, is also associated with a good long-term outcome, is as safe as other treatment regimes, and performs as well as the combination of high-dose MTX and the tumor necrosis factor antagonist infliximab. A pilot study with an intensified version of the COBRA combination therapy showed that strict monitoring and aggressive treatment intensification based on the Disease Activity Score can result in a remission rate of 90% in patients with active early RA. Also, the first results indicate that an attenuated variation on COBRA combination therapy, called 'COBRA-light', is effective in decreasing disease activity and is generally well tolerated. Based on these results, we conclude that initial high-dose prednisolone in combination with MTX and SSZ could or should be the first choice in early active RA since it is effective and safe, and the cost price of the drugs is low.

Novel multimeric IL-1 receptor antagonist for the treatment of rheumatoid arthritis

Protein therapeutics targeting inflammatory mediators have shown great promise for the treatment of autoimmunities such as rheumatoid arthritis (RA). However, a significant challenge in this area has been their low in vivo stability and consequently their severely compromised therapeutic efficacy. One such therapeutic molecule IL-1 receptor antagonist (IL-1ra), used in the treatment of rheumatoid arthritis, has displayed only modest efficacy in human clinical trials owing to its short biological half-life. Herein, we report a novel approach to conglomerate individual protein entities into a drug depot by incorporation of an amyloidogenic motif Lys-Phe-Phe-Glu (KFFE) thereby dramatically improving their systemic persistence and in turn their therapeutic efficacy in a mice model of autoimmune arthritis.

The chondrocyte primary cilium

The presence and role of primary, or non-motile, cilia on chondrocytes has confused cartilage researchers for decades. Initial explanations attributed a vestigial nature to chondrocyte cilia. Evidence is now emerging that supports the role of the chondrocyte primary cilium as a sensory organelle, in particular, in mechanotransduction and as a compartment for signaling pathways. Early electron microscopy images depicted bent cilia aligned with the extracellular matrix (ECM) in a manner that suggested a response to mechanical forces. Molecules known to be mechanotransducers in other cell types, including integrins and proteoglycans, are present on chondrocyte cilia. Further, chondrocytes which lack cilia fail to respond to mechanical forces in the same manner that chondrocytes with intact cilia respond. From a clinical perspective, chondrocytes from osteoarthritic (OA) cartilage have cilia with different characteristics than cilia found on chondrocytes from healthy cartilage.

OBJECTIVE

This review examines the evidence supporting the function of chondrocyte cilia and briefly speculates on the involvement of intraflagellar transport (IFT) in the signaling pathway of mechanotransduction through the cilium.

CONCLUSIONS

Emerging evidence suggests cilia may be a promising target for preventing and treating OA.

Pretreatment multi-biomarker disease activity score and radiographic progression in early RA: results from the SWEFOT trial

Objectives

Prediction of radiographic progression (RP) in early rheumatoid arthritis (eRA) would be very useful for optimal choice among available therapies. We evaluated a multi-biomarker disease activity (MBDA) score, based on 12 serum biomarkers as a baseline predictor for 1-year RP in eRA.

Methods

Baseline disease activity score based on erythrocyte sedimentation rate (DAS28-ESR), disease activity score based on C-reactive protein (DAS28-CRP), CRP, MBDA scores and DAS28-ESR at 3 months were analysed for 235 patients with eRA from the Swedish Farmacotherapy (SWEFOT) clinical trial. RP was defined as an increase in the Van der Heijde-modified Sharp score by more than five points over 1 year. Associations between baseline disease activity measures, the MBDA score, and 1-year RP were evaluated using univariate and multivariate logistic regression, adjusted for potential confounders.

Results

Among 235 patients with eRA, 5 had low and 29 moderate MBDA scores at baseline. None of the former and only one of the latter group (3.4%) had RP during 1 year, while the proportion of patients with RP among those with high MBDA score was 20.9% (p=0.021). Among patients with low/moderate CRP, moderate DAS28-CRP or moderate DAS28-ESR at baseline, progression occurred in 14%, 15%, 14% and 15%, respectively. MBDA score was an independent predictor of RP as a continuous (OR=1.05, 95% CI 1.02 to 1.08) and dichotomised variable (high versus low/moderate, OR=3.86, 95% CI 1.04 to 14.26).

Conclusions

In patients with eRA, the MBDA score at baseline was a strong independent predictor of 1-year RP. These results suggest that when choosing initial treatment in eRA the MBDA test may be clinically useful to identify a subgroup of patients at low risk of RP.

Trial registration number

WHO database at the Karolinska Institute: CT20080004; and clinicaltrials.gov: NCT00764725.

Usefulness of urinary CTX-II and NTX-I in evaluating radiological knee osteoarthritis : the Matsudai knee osteoarthritis survey

BACKGROUND

To assess the usefulness of the urinary crosslinked C-telopeptide of type II collagen (uCTX-II) or crosslinked N-telopeptide of type I collagen (uNTX-I) for evaluating radiological knee osteoarthritis (OA), a cross-sectional study was conducted in the cohorts of the Matsudai knee osteoarthritis survey performed in Niigata, Japan.

METHODS

Urine specimens and standing knee AP X-rays were obtained from 1040 subjects who provided informed consent. The relationship between these markers and gender, age (patients aged 40-59 or 60-79 years), use of bisphosphonates, and OA grades (K-L classification) were analyzed. The diagnostic ability of uCTX-II to detect radiological knee OA was confirmed in the over 60-year-old subjects using a ROC curve.

RESULTS

The over 60-year-old men with OA grade 3,4 group had significantly higher uCTX-II levels than the other OA grade groups. In the over 60-year-old women, the uCTX-II levels significantly increased according to the progression of the knee OA grade. No significant difference was observed between the uNTX-I levels in the different OA grade groups. From the standpoint of biomarkers, the higher quartiles of the uCTX-II and uNTX-I levels gradually included higher numbers of grade ≥2 OA subjects in the over 60 year-old women. The area under the curve (AUC) in ROC analysis of uCTX-II exhibited a significant association with the diagnosis of knee OA in women (AUC 0.63), although the accuracy was evaluated to be low in the single measurement of our health checkup-based analysis.

CONCLUSIONS

This population-based study indicates that the uCTX-II level is strongly correlated with the knee OA grade in women over age 60. A further analysis is needed to clarify its predictive accuracy.

Bone remodelling markers in rheumatoid arthritis

Bone loss in rheumatoid arthritis (RA) patients results from chronic inflammation and can lead to osteoporosis and fractures. A few bone remodeling markers have been studied in RA witnessing bone formation (osteocalcin), serum aminoterminal propeptide of type I collagen (PINP), serum carboxyterminal propeptide of type I collagen (ICTP), bone alkaline phosphatase (BAP), osteocalcin (OC), and bone resorption: C-terminal telopeptide of type 1 collagen (I-CTX), N-terminal telopeptide of type 1 collagen (I-NTX), pyridinolines (DPD and PYD), and tartrate-resistant acid phosphatase (TRAP). Bone resorption can be seen either in periarticular bone (demineralization and erosion) or in the total skeleton (osteoporosis). Whatever the location, bone resorption results from activation of osteoclasts when the ratio between osteoprotegerin and receptor activator of nuclear factor kappa-B ligand (OPG/RANKL) is decreased under influence of various proinflammatory cytokines. Bone remodeling markers also allow physicians to evaluate the effect of drugs used in RA like biologic agents, which reduce inflammation and exert a protecting effect on bone. We will discuss in this review changes in bone markers remodeling in patients with RA treated with biologics.

Could biomarkers of bone, cartilage or synovium turnover be used for relapse prediction in rheumatoid arthritis patients?

OBJECTIVE

The aim of this review is to clarify the usefulness of bone, cartilage, and synovial biomarker in the management of rheumatoid arthritis (RA) therapy in remission. SYNOVIAL BIOMARKERS: High MMP-3 levels are associated with joint progression in RA patients, but there is no data about their utility in clinical remission. IIINys and Glc-Gal-PYD seem to be more specific to synovium, but more studies are required. CARTILAGE BIOMARKERS: Unbalance between cartilage break-down biomarkers (urinary CTX II and COMP) and cartilage formation biomarker (PIIANP) was described. This unbalance is also associated with joint destruction and prognosis of destruction. No data are available on patients in remission. BONE BIOMARKERS: RA activity is correlated with an increase of bone resorption markers such as CTX I, PYD, and TRACP 5b and a decrease of bone formation markers such as OC and BALP. RA therapies seem to improve bone turnover in limiting bone resorption. There is no study about bone marker utility in remission.

CONCLUSION

Biomarkers seem to correlate with RA activity and progression. They also could be used to manage RA therapies, but we need more data on RA remission to predict relapse.

Updating the OMERACT filter: implications for imaging and soluble biomarkers

OBJECTIVE

The Outcome Measures in Rheumatology (OMERACT) Filter provides a framework for the validation of outcome measures for use in rheumatology clinical research. However, imaging and biochemical measures may face additional validation challenges because of their technical nature. The Imaging and Soluble Biomarker Session at OMERACT 11 aimed to provide a guide for the iterative development of an imaging or biochemical measurement instrument so it can be used in therapeutic assessment.

METHODS

A hierarchical structure was proposed, reflecting 3 dimensions needed for validating an imaging or biochemical measurement instrument: outcome domain(s), study setting, and performance of the instrument. Movement along the axes in any dimension reflects increasing validation. For a given test instrument, the 3-axis structure assesses the extent to which the instrument is a validated measure for the chosen domain, whether it assesses a patient-centered or disease-centered variable, and whether its technical performance is adequate in the context of its application. Some currently used imaging and soluble biomarkers for rheumatoid arthritis, spondyloarthritis, and knee osteoarthritis were then evaluated using the original OMERACT Filter and the newly proposed structure. Breakout groups critically reviewed the extent to which the candidate biomarkers complied with the proposed stepwise approach, as a way of examining the utility of the proposed 3-dimensional structure.

RESULTS

Although there was a broad acceptance of the value of the proposed structure in general, some areas for improvement were suggested including clarification of criteria for achieving a certain level of validation and how to deal with extension of the structure to areas beyond clinical trials.

CONCLUSION

General support was obtained for a proposed tri-axis structure to assess validation of imaging and soluble biomarkers; nevertheless, additional work is required to better evaluate its place within the OMERACT Filter 2.0.

The clinical utility of bone turnover markers in the evaluation of bone disease in patients with haemophilia A and B

Haemophilia A and B have been associated with increased prevalence of low bone mineral density (BMD). However, the utility of bone turnover markers (BTM) remains unknown. The aim of this study was to evaluate bone metabolism in men with haemophilia and to investigate associations between BTM and bone disease. Serum N- (NTX-I), C-terminal telopeptide of type I collagen (CTX-I) and tartrate-resistant acid phosphatase band-5b (TRAP-5b), as bone resorption markers, and osteocalcin (OC) and bone-specific alkaline phosphatase (b-ALP), as bone formation markers, were assessed. Seventy men with haemophilia A (n = 59) or B (n = 11) were studied. Patients with low BMD had significantly higher b-ALP concentrations compared with those with normal BMD (12.8 ± 1.60 vs. 9.72 ± 0.58 μg/L, P = 0.009), without any differences in the other BTM. NTX-I and CTX-I concentrations were negatively associated with oestradiol levels and hip BMD and positively with human immunodeficiency virus infection, number of affected joints and arthropathy scores. B-ALP and OC concentrations were negatively associated with hip BMD, severity of haemophilia and fracture history, and positively with the number of affected joints and testosterone concentrations. After multivariate analysis, NTX-I levels remained negatively associated with oestradiol levels, whereas b-ALP concentrations negatively correlated with the level of physical activity and positively with the number of affected joints. Increased bone metabolism exists in men with haemophilia and low BMD. Increased b-ALP levels may identify patients at high risk for fracture. Increased number of target joints, low physical activity and low oestradiol concentrations are independently associated with increased bone metabolism.

Serological identification of fast progressors of structural damage with rheumatoid arthritis

Introduction

Rheumatoid arthritis (RA) patients with structural progression are in most need of immediate treatment to maintain tissue integrity. The serum protein fingerprint, type I collagen degradation mediated by matrix metalloproteinases (MMP)-cleavage (C1M), is a biomarker of tissue destruction. We investigated whether baseline serum C1M levels could identify structural progressors and if the biomarker levels changed during anti-inflammatory treatment with tocilizumab (TCZ).

Methods

The LITHE-biomarker study (NCT00106535, n = 585) was a one-year phase III, double-blind, placebo (PBO)-controlled, parallel group study of TCZ 4 or 8 mg/kg every four weeks, in RA patients on stable doses of methotrexate (MTX). Spearman's ranked correlation was used to assess the correlation between baseline C1M levels and structural progression at baseline and at weeks 24 and 52. Multivariate regression was performed for delta structural progression. Change in C1M levels were studied as a function of time and treatment.

Results

At baseline, C1M was significantly correlated to C-reactive protein (P <0.0001), visual analog scale pain (P <0.0001), disease activity score28-erythrocyte sedimentation rate (DAS28-ESR) (P <0.0001), joint space narrowing (JSN) (P = 0.0056) and modified total Sharp score (mTSS) (P = 0.0006). Baseline C1M was significantly correlated with delta-JSN at Week 24 (R² = 0.09, P = 0.0001) and at Week 52 (R² = 0.27, P <0.0001), and with delta-mTSS at 24 weeks (R² = 0.006, P = 0.0015) and strongly at 52 weeks (R² = 0.013, P <0.0001) in the PBO group. C1M levels were dose-dependently reduced in the TCZ + MTX group.

Conclusions

Baseline C1M levels correlated with worsening joint structure over one year. Serum C1M levels may enable identification of those RA patients that are in most need of aggressive treatment

Trial registration

ClinicalTrials.gov: NCT00106535

Plasma osteopontin is correlated with bone resorption markers in rheumatoid arthritis patients

AIM

To assess whether any form of osteopontin (OPN) is correlated with bone resorption markers or treatment effects in rheumatoid arthritis (RA).

METHOD

Subjects comprised 119 patients with RA. RA disease activity was evaluated by Disease Activity Score (DAS) 28, erythrocyte sedimentation rate (ESR), and levels of C-reactive protein (CRP), rheumatoid factor (RF) and matrix metalloproteinase (MMP)-3. OPN levels in plasma and urine were measured by enzyme-linked immunosorbent assay (ELISA). Levels of tartrate-resistant acid phosphatase (TRACP) 5b in serum and C-terminal telopeptide of type 1 collagen (CTX)-1 in urine were measured by ELISA. Patients were divided into responder and nonresponder groups, and OPN levels were compared at baseline and after treatment.

RESULTS

Levels of full-length OPN in plasma (P-fOPN) were significantly correlated with levels of TRACP 5b (r = 0.44, P < 0.001), urine CTX-1 (r = 0.26, P = 0.004) and MMP-3 (r = 0.34, P < 0.001). Levels of TRACP 5b were significantly correlated with age (r = 0.25, P = 0.007), but levels of P-fOPN were not. After treatment, plasma OPN levels were significantly decreased in responders (P = 0.003). Levels of full-length or thrombin-cleaved forms of OPN in urine were not correlated with TRACP 5b or CTX-1.

CONCLUSION

Our results suggest that plasma OPN may reflect inflammatory bone destruction in RA patients.

Serum pyridinoline levels and prediction of severity of joint destruction in rheumatoid arthritis

OBJECTIVE

Previous studies indicated that pyridinoline, a collagen crosslink in cartilage and bone, might be a good marker to predict joint destruction in patients with rheumatoid arthritis (RA), although large prospective studies are lacking. We evaluated the predictive value of serum pyridinoline levels for joint destruction, both at baseline for longterm prediction and during the disease course for near-term prediction.

METHODS

Patients with early RA from the Leiden Early Arthritis Clinic were studied. Radiographs at baseline and yearly during 7 years of followup were scored according to the Sharp-van der Heijde Scoring (SHS) method. Pyridinoline serum levels at baseline and during followup were measured by ELISA. The association between baseline pyridinoline levels and difference in SHS over 7 years was tested, with a multivariate normal regression model. Second, the association between pyridinoline levels determined during the disease course and progression of SHS over the next year was tested with a multivariable linear regression analysis.

RESULTS

Studying baseline pyridinoline serum levels in 437 patients revealed that the mean SHS over 7 years was 6% higher for every higher pyridinoline level (nmol/l) at baseline (p = 0.001). Subsequently, during followup (n = 184 patients) the progression in SHS in the upcoming year was 17% higher for every higher nmol/l pyridinoline level (p = 0.001). The area under the receiver-operation characteristic curve for rapid radiological progression was 0.59.

CONCLUSION

Increased pyridinoline serum levels, both at baseline and during the disease course, are associated with more severe joint destruction during the coming year(s), although the predictive accuracy as a sole predictor was moderate.

Biologic therapies and systemic bone loss in rheumatoid arthritis

Chronic inflammation affects bone metabolism leading to disequilibrium in the rates of bone resorption and repair and subsequently to local and generalized bone loss. Osteoporosis represents an important co-morbidity of rheumatoid arthritis (RA) patients, which exhibit increased fracture risk. Osteoclasts play a pivotal role in the development and progression of bone loss, while resident synovial cells such as T cells, monocytes and synovial fibroblasts have been identified as sources of osteoclast differentiation signals in RA. This process is mainly mediated through the receptor activator of nuclear-kappa B ligand (RANKL) signalling system, which is upregulated by numerous proinflammatory cytokines involved in the pathogenesis of RA. Improved knowledge of the association between cells and cytokines of the immune system and their relationship to bone remodeling has revealed several promising targets for the treatment of inflammatory bone loss in RA. In this respect, initiation of biologic therapies targeting inflammatory cytokines and/or lymphocyte activation has modified RA therapy not only by blocking local and systemic inflammatory cascades but also by providing beneficial effects against bone and joint degradation. In this article we briefly present the modern view of the mechanisms that govern inflammatory bone loss, highlighting the role of cytokine-induced molecular pathways, and discuss in detail the effects of different biologic treatment strategies on bone mass in RA patients.

Periarticular bone gain at proximal interphalangeal joints and changes in bone turnover markers in response to tumor necrosis factor inhibitors in rheumatoid and psoriatic arthritis

OBJECTIVE

Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) are characterized by periarticular bone erosion; periarticular bone formation is a feature in PsA. The effect of anti-tumor necrosis factor-α (TNF-α) on periarticular bone remodeling is unclear in both diseases. Our aim was to assess the response of bone turnover markers (BTM) and hand bone mineral density (BMD) to anti-TNF over 3 years in RA and PsA.

METHODS

We measured serum bone-specific alkaline phosphatase (bone ALP), procollagen type-I N-propeptide (PINP), intact osteocalcin, C-terminal cross-linking telopeptides (CTX-I), urinary N-terminal cross-linking telopeptide of type-I collagen (NTX-I), and free deoxypyridinoline crosslinks (fDPD) at baseline, 1, 12, and 36 months. BMD measurements (hands/spine/hip) were obtained at 3 timepoints.

RESULTS

We recruited 62 patients (RA 35; PsA 27). BTM correlated significantly with hand BMD but not with central BMD. Low hand BMD was associated with RA and increased BTM. Following anti-TNF therapy, hip BMD declined while spine and hand BMD were unchanged. Periarticular BMD at proximal interphalangeal (PIP) joints increased while it decreased at metacarpophalangeal joints. Bone ALP increased steadily and was always higher in PsA. PINP and intact osteocalcin increased to a lesser extent, but resorption markers did not change.

CONCLUSION

At baseline, hand BMD was inversely associated with BTM. Bone formation rather than resorption markers better showed the bone response to anti-TNF. Despite a lack of effect on central BMD, the modest effect of anti-TNF on PIP BMD may provide evidence that BTM reflect specifically bone remodeling activity at periarticular sites of inflammation in RA and PsA.

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.

Common bone turnover markers in rheumatoid arthritis and ankylosing spondylitis: a literature review

We studied the impact of inflammatory rheumatism and its treatment on the most common bone turnover markers, based on six previously defined questions in a systematic literature review in order to define their place in daily clinical practice. The role of bone is currently considered of particular importance concerning cartilage damage in inflammatory rheumatism (rheumatoid arthritis and ankylosing spondylitis) and the new concept of osteoimmunology has emerged. Some bone turnover markers are available in clinical practice. In spite of rich and extensive literature on bone turnover markers, their use in inflammatory rheumatism or even osteoporosis is not clear, and a systematic literature review became necessary. In spite of a large number of different markers used in literature, few of them that are useful in common practice have been studied in the field of inflammatory rheumatism such as rheumatoid arthritis and ankylosing spondylitis. Although their study enables understanding of the physiopathological mechanisms of osteoporosis in inflammatory rheumatism, their use in current common practice cannot be recommended. Interesting data on the forecast of the structural evolution of rheumatoid arthritis has been found within the framework of clinical research, without any real practical impact today.

Prevention of cartilage degeneration and gait asymmetry by lubricin tribosupplementation in the rat following anterior cruciate ligament transection

OBJECTIVE

To investigate whether cartilage degeneration is prevented or minimized in a rat model of anterior cruciate ligament (ACL) injury following a single dose-escalated intraarticular injection of lubricin derived from human synoviocytes in culture.

METHODS

Unilateral ACL transection (ACLT) of the right hind limb was performed in Lewis rats (n = 56). Control animals underwent a capsulotomy alone, leaving the ACL intact (n = 11). Intraarticular injections (50 μl/injection) of phosphate buffered saline (PBS; n = 14 rats) and human synoviocyte lubricin (1,600 μg/ml; n = 14 rats) were performed on day 7 postsurgery. Animals were killed on day 70 postsurgery. Histologic specimens were immunoprobed for lubricin and sulfated glycosaminoglycans. Urinary C-telopeptide of type II collagen (CTX-II) levels were measured on days 35 and 70 postsurgery. Hind limb maximum applied force was determined using a variable resistor walkway to monitor quadruped gait asymmetries.

RESULTS

Increased immunostaining for lubricin in the superficial zone and on the surface of cartilage was observed in lubricin-treated and control animals but not in PBS-treated or untreated animals with ACLT. On days 35 and 70 after surgery, urinary CTX-II levels in human synoviocyte lubricin-treated animals were lower than in untreated and PBS-treated animals (P < 0.005 and P < 0.001, respectively). Animals with ACLT treated with human synoviocyte lubricin and control animals distributed their weight equally between hind limbs compared to PBS-treated or untreated animals (P < 0.01).

CONCLUSION

Our findings indicate that a single intraarticular injection of concentrated lubricin following ACLT reduces type II collagen degradation and improves weight bearing in the affected rat joint. These findings support the practice of tribosupplementation with lubricin for retarding cartilage degeneration and possibly the development of posttraumatic osteoarthritis.