Adipocytokines are associated with radiographic joint damage in rheumatoid arthritis

Objective

Obesity protects against radiographic joint damage in rheumatoid arthritis (RA) through poorly defined mechanisms. Adipocytokines are produced in adipose tissue and modulate inflammatory responses and radiographic joint damage in animal models. The purpose of this study was to examine the hypothesis that adipocytokines modulate inflammation and radiographic joint damage in patients with RA.

Methods

We compared serum concentrations of leptin, resistin, adiponectin, and visfatin in 167 RA patients and 91 control subjects. The independent association between adipocytokines and body mass index (BMI), measures of inflammation (C‐reactive protein [CRP], interleukin‐6 [IL‐6], and tumor necrosis factor α [TNFα]), and radiographic joint damage (Larsen score; n = 93 patients) was examined in RA patients by multivariable regression analysis first controlling for age, race, and sex, and then for obesity (BMI) and inflammation (TNFα, IL‐6, and CRP).

Results

Concentrations of all adipocytokines were significantly higher in RA patients than in controls; for visfatin and adiponectin, this association remained significant after adjusting for BMI, inflammation, or both. Visfatin concentrations were associated with higher Larsen scores, and this association remained significant after adjustment for age, race, sex, disease duration, BMI, and inflammation (odds ratio [OR] 2.38 [95% confidence interval (95% CI) 1.32–4.29], P = 0.004). Leptin concentrations showed a positive association with the BMI (ρ = 0.58, P < 0.01) and showed a negative association with the Larsen score after adjustment for inflammation (OR 0.32 [95% CI 0.17–0.61], P < 0.001), but not after adjustment for BMI (OR 0.86 [95% CI 0.42–1.73], P = 0.67).

Conclusion

Concentrations of adipocytokines are increased in patients with RA and may modulate radiographic joint damage. Visfatin is associated with increased, and leptin with reduced, levels of radiographic joint damage.

     

Predictors of radiographic joint damage in patients with early rheumatoid arthritis

OBJECTIVE: To determine factors at diagnosis, associated with radiographic damage at diagnosis and after one year, in patients with early rheumatoid arthritis (RA). METHODS: New patients with early RA were followed up for one year. Possible prognostic factors were duration of complaints, morning stiffness, disease activity score (DAS28), functional status (Health Assessment Questionnaire (HAQ) score), rheumatoid factor (IgM RF), and C reactive protein (CRP). Outcome was defined as radiographic damage of the hands and feet (Sharp/van der Heijde score). For the statistical analysis, one way analysis of variance and a forward stepwise logistic regression model was used. RESULTS: 130 patients with RA (68% female; median age 64 years, range 21-86) were included. Despite the fact that the median duration of complaints was short (15 weeks, range 2-106) the radiographic damage at diagnosis was significantly correlated with the duration of complaints (p<0.05). Patients with a duration of complaints of >34 weeks had significantly more radiographic joint damage at diagnosis than patients with a shorter duration of complaints. Radiographic progression at one year was correlated with high radiographic joint damage, high CRP level, and a positive IgM RF at entry. CONCLUSIONS: In early RA, the number of radiographic lesions was correlated with a longer duration of complaints at the first visit. Progression of these lesions was predicted by a high baseline joint damage, high CRP level, and a positive IgM RF. Further reduction of the delay in referral and early treatment may further decrease joint damage in patients with recent onset polyarthritis.     

Antiferritin antibodies discovered by phage display expression cloning are associated with radiographic damage in rheumatoid arthritis

OBJECTIVE: Several autoantibodies have been described in individuals with rheumatoid arthritis (RA), leading to interest in the use of such antibodies as diagnostic or prognostic markers in RA as well as in their relevance to disease pathology. The objective of this study was to use a phage display expression cloning system to identify novel autoantibody targets in RA. METHODS: We used immunoscreening of a phage-displayed complementary DNA (cDNA) library to isolate a cDNA clone encoding the ferritin heavy chain polypeptide. Antiferritin antibody levels in patients with early and established RA, healthy controls, and disease controls were measured by enzyme-linked immunosorbent assay. Antibody-positive and antibody-negative individuals were compared with respect to disease severity as measured by the modified Larsen score, demographic variables, rheumatoid factor status, and carriage of HLA-DRB1 shared epitope alleles. RESULTS: Antiferritin antibodies were present in 60 (16%) of 366 patients with established RA, 23 (19%) of 118 patients with early RA, 2 (2.7%) of 73 healthy blood donors, 2 (2.1%) of 94 individuals with osteoarthritis, and 2 (2.1%) of 97 patients with systemic lupus erythematosus (P < 0.01, RA patients versus healthy and disease controls). Antiferritin antibodies were more common in men than in women (28.4% versus 12.2%; P < 0.001), and antiferritin levels were associated with the severity of joint damage (P = 0.01). CONCLUSION: Antiferritin antibodies are observed in a subset of patients with RA, are present early in the disease course, and are associated with the severity of radiographic damage. Further studies are required to explore their potential as diagnostic and prognostic markers in RA.     

Enhanced concentrations of interleukin 16 are associated with joint destruction in patients with rheumatoid arthritis

OBJECTIVE: To investigate the role of interleukin 16 (IL-16) in the development of rheumatoid arthritis (RA) and joint destruction. METHODS: We measured systemic IL-16 levels longitudinally in 39 patients with recent-onset RA, in 13 patients with initially undifferentiated arthritis who will develop RA over time, in 15 patients with undifferentiated arthritis, and in 12 healthy controls, and correlated the levels with joint damage and disease activity. Systemic IL-16 levels were measured by ELISA. Joint destruction was measured according to the Sharp method and the disease activity variables included C-reactive protein (CRP) and Disease Activity Score (DAS) measured at disease onset, and after one and 2 years of followup. RESULTS: A significantly increased IL-16 level in RA patients at disease onset [median (25th-75th percentile) 45.2 (37.7-82.4) pg/ml] was observed compared to both controls [30.4 (24.4-37.0) pg/ml, p = 0.0008], and to patients with undifferentiated arthritis [29.0 (21.5-52.4) pg/ml; p = 0.005]. The IL-16 levels of the patients who presented with undifferentiated arthritis but who developed RA over time were also increased [47.9 (34.5-108.2) pg/ml] compared to the controls (p = 0.004) and to the patients who over time remained diagnosed with undifferentiated arthritis (p = 0.01). We found that high IL-16 levels correlated positively with joint destruction during the 2-year followup (p = 0.02) and not with the disease activity variables. CONCLUSION: Our results suggest that the cytokine IL-16 plays a role in the disease process underlying RA and joint destruction.     

Autoantibodies recognizing carbamylated proteins are present in sera of patients with rheumatoid arthritis and predict joint damage

Autoimmune responses against posttranslationally modified antigens are a hallmark of several autoimmune diseases. For example, antibodies against citrullinated protein antigens (ACPA) have shown their relevance for the prognosis and diagnosis of rheumatoid arthritis (RA), and have been implicated in disease pathogenesis. It is conceivable that other autoantibody systems, recognizing other posttranslationally modified proteins, are also present in RA. Here, we describe the presence of an autoantibody system that discriminates between citrulline- and homocitrulline-containing antigens in the sera of RA-patients. IgG antibodies recognizing carbamylated (homocitrulline-containing) antigens were present in sera of over 45% of RA-patients. Likewise, anticarbamylated protein (anti-CarP) IgA antibodies were observed in 43% of RA-sera. ACPA and anti-CarP antibodies are distinct autoantibodies because, in selected double-positive patients, the anti-CarP antibody binding to carbamylated antigens could be inhibited by carbamylated antigens, but not by control or citrullinated antigens. Similarly, ACPA-binding to citrullinated antigens could only be inhibited by citrullinated antigens. In line with this observation, 16% of ACPA-negative RA-patients, as measured by a standard ACPA assay, harbored IgG anti-CarP antibodies, whereas 30% of these patients tested positive for IgA anti-CarP antibodies. The presence of anti-CarP antibodies was predictive for a more severe disease course in ACPA-negative patients as measured by radiological progression. Taken together, these data show the presence of a unique autoantibody system recognizing carbamylated, but not citrullinated, protein antigens. These antibodies are predictive for a more severe clinical course in ACPA-negative RA-patients, indicating that anti-CarP antibodies are a unique and relevant serological marker for ACPA-negative RA.     

High serum levels of pro-matrix metalloproteinase-3 are associated with greater radiographic damage and the presence of the shared epitope in patients with rheumatoid arthritis

OBJECTIVE: To determine if there is a relationship between serum pro-matrix metalloproteinase-3 (proMMP-3) levels and radiographic damage in rheumatoid arthritis (RA), and to investigate whether high levels are associated with presence of the HLA-DRB1 shared epitope (SE). METHODS: Serum proMMP-3 levels were measured by ELISA on 45 RA patients with early disease and 292 with established disease. Early RA was arbitrarily defined as disease duration <3 years. Clinical and laboratory measures of disease activity and severity were obtained. Radiographic damage was assessed by scoring radiographs of the hands and feet using the method of Larsen. HLA-DRB1 typing was performed by sequence-specific oligonucleotide probing. Data were analyzed by multiple regression analysis. RESULTS: In all patients, there was a correlation (r = 0.318, p<0.0001) between serum proMMP-3 levels and Larsen scores. Other correlations were found with Health Assessment Questionnaire score (r = 0.261, p<0.0001) and C-reactive protein (CRP) (r = 0.357, p<0.0001) levels. ProMMP-3 levels were significantly higher in SE+/+ patients than in those completely lacking the SE, with the highest levels in patients carrying an HLA-DRI+/DR4+ phenotype. The greatest difference in proMMP-3 levels between SE+/+ and SE-/- patients was in those with a disease duration <3 years (381.6 vs. 71.7 ng/ml; p = 0.02). CONCLUSION: Our data indicate that there is a significant relationship between radiographic damage and serum levels of proMMP-3. As well, higher circulating levels of proMMP-3 are found in patients positive for the SE, particularly in early RA, and this may partly explain the association between the SE and more erosive disease.     

Antilactoferrin antibodies in patients with rheumatoid arthritis are associated with vasculitis

Objective. To determine the occurrence of antineutrophil cytoplasmic antibodies (ANCA) and the specificity of these antibodies (Ab) in serum from patients with rheumatoid arthritis (RA) and patients with rheumatoid arthritis complicated by vasculitis (rheumatoid vasculitis [RV]). Methods. ANCA was detected with an indirect immunofluorescence test on ethanol-fixed granulocytes. Ab against the cytoplasmic antigens proteinase-3, elastase, lactoferrin (LF), and myeloperoxidase were measured by enzyme-linked immunosorbent assay. Results. ANCA were found in the serum of 43% of 49 patients with RV and in 36% of 50 patients with RA. Anti-LF Ab occurred more frequently in RV patients (45%) than in RA patients (4%), whereas reactivity against the other cytoplasmic antigens did not differ significantly between these groups. Conclusion. Anti-LF Ab in serum of patients with RA may be useful in the diagnosis of vasculitis in RA.     

T cells, fibroblast-like synoviocytes, and granzyme B+ cytotoxic cells are associated with joint damage in patients with recent onset rheumatoid arthritis

OBJECTIVE: To determine immunohistological markers in synovial tissue of patients with early rheumatoid arthritis (RA) which are associated with unfavourable disease outcome. METHODS: Synovial tissue was obtained from 36 patients with RA within 1 year after the initial symptoms and before starting disease modifying antirheumatic drug treatment. Clinical, laboratory, and radiological assessments (Larsen score) were performed at the time of the biopsy and at the end of follow up (mean 58 months, range 38-72). Immunohistological analysis was performed to detect T cells, B cells, plasma cells, fibroblast-like synoviocytes (FLS), macrophages, and granzyme B+ cytotoxic cells. The sections were evaluated by digital image analysis. RESULTS: Patients were divided into two groups based upon the radiological progression per year of follow up: group I with mild progression (n = 20; Larsen <2 points/year); group II with more severe progression (n = 16; Larsen > or =2 points/year). Regression analysis with a univariate model showed that the numbers of granzyme B+ cytotoxic cells (relative risk (RR) = 12, p = 0.003), T cells (RR = 11, p = 0.013), and FLS (RR = 10, p = 0.020) discriminated between groups I and II. A multivariate model demonstrated that the numbers of T cells (RR = 1.2, p = 0.015) and FLS (RR = 1.4, p = 0.013) were independent discriminators between groups I and II. CONCLUSION: The numbers of granzyme B+ cytotoxic cells, T cells, and FLS in synovial tissue of patients with RA are related to the severity of joint damage. The data suggest a pathogenetic role for these cells in the process of joint damage.     

Inflammation and damage in an individual joint predict further damage in that joint in patients with early rheumatoid arthritis

OBJECTIVE; Several factors predict joint damage in early rheumatoid arthritis (RA). In the context of a trial in early RA, we studied the relationship between clinical signs in individual joints and their propensity to develop progressive damage. METHODS: The COBRA (Combinatietherapie Bij Reumatoide Artritis) multicenter trial compared the efficacy of prednisolone, methotrexate, and sulfasalazine against sulfasalazine alone in 155 patients with early RA. Two blinded observers interpreted radiographs in sequence (using the Sharp/Van der Heijde scoring system); in each center, one blinded observer performed clinical assessments every 3 months. The current analysis is based on clinical and radiologic data of the individual metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints of 135 patients. Conditional stepwise logistic regression analyzed the relationship between damage (progression) and clinical signs at baseline and followup for each of these joints individually in each patient. RESULTS: Combination therapy strongly retarded the progression of damage. Progression was stronger in patients with rheumatoid factor, HLA-DR4, and high levels of disease activity at baseline. At baseline, 6% of the MCP and PIP joints showed damage; after 1 year, disease had progressed in 10% of these joints. Baseline damage, swelling, or pain in a joint independently and strongly predicted the progression of damage in that joint (P < 0.001). Each additional point in the swelling score (range 0-2) tripled the risk for subsequent progression. Each additional point on the Sharp scale (range 0-8 per joint) and each additional point on the pain scale (range 0-3) doubled the risk. The mean pain and swelling scores over the year were even stronger predictors of damage. CONCLUSION: Local expression of early RA disease activity, both at baseline and at 1-year followup, is strongly related to progression of damage in the individual joint.     

Etanercept versus methotrexate in patients with early rheumatoid arthritis: two-year radiographic and clinical outcomes

OBJECTIVE: To compare the clinical and radiographic outcomes in patients with rheumatoid arthritis (RA) who received monotherapy with either etanercept or methotrexate (MTX) for 2 years and to assess the safety of this therapy. METHODS: In the Enbrel ERA (early rheumatoid arthritis) trial, 632 patients with early, active RA were randomized to receive either twice-weekly subcutaneous etanercept (10 mg or 25 mg) or weekly oral MTX (mean dosage 19 mg per week) for at least 1 year in a double-blind manner. Following the blinded phase of the trial, 512 patients continued to receive the therapy to which they had been randomized for up to 1 additional year, in an open-label manner. Radiograph readers remained blinded to treatment group assignment and the chronologic order of images. RESULTS: At 24 months, more 25-mg etanercept patients than MTX patients met American College of Rheumatology 20% improvement criteria (72% and 59%, respectively; P = 0.005), and more had no increase in total score and erosion scores on the Sharp scale (P = 0.017 and P = 0.012, respectively). The mean changes in total Sharp score and erosion score in the 25-mg etanercept group (1.3 and 0.66 units, respectively) were significantly lower than those in the MTX group (3.2 and 1.86 units, respectively; P = 0.001). Significantly more patients in the 25-mg etanercept group (55%) than in the MTX group (37%) had at least 0.5 units of improvement in the Health Assessment Questionnaire disability index (P < 0.001). Fewer patients in the etanercept group than in the MTX group experienced adverse events or discontinued treatment because of adverse events. CONCLUSION: Etanercept as monotherapy was safe and was superior to MTX in reducing disease activity, arresting structural damage, and decreasing disability over 2 years in patients with early, aggressive RA.     

An overview of radiographic analysis of joint damage in rheumatoid arthritis and its use in metaanalysis

A brief history of the development of scoring methods to represent the extent of radiographic abnormalities in rheumatoid arthritis shows that grading systems have become more detailed with time. Taken together with the observation that physicians continue to modify scoring methods it is clear that we have not yet arrived at the ideal method. Issues to be considered in evaluating scoring methods include which abnormalities and which joints to score and what scale to use. Data from one early trial indicate that erosion and joint space narrowing scores do not progress in lockstep and progression in one does not predict progression in the other; this leads to the conclusion that including both features in a scoring method is important. Data from the same trial raise the possibility that joint space narrowing scores for the proximal interphalangeal finger joints may not be helpful in detecting treatment differences, illustrating that further investigation of which joints to include in scoring is needed. The possibility that an expanded scoring scale might be more sensitive to recording a change in radiographic damage also was raised. A simple method of determining which patients show progression of damage was proposed based on assessing the distribution of negative progression scores (baseline erosion scores subtracted from followup scores adjusted for time). It was pointed out that radiographic assessment has established that a few drugs slow the progression of joint damage. Radiographic evaluation of disease progression should continue to be utilized as an outcome measure in evaluating new therapies.     

Pathogenesis of joint damage in rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by the appearance of progressive joint damage that may be identified only months after the onset of symptoms. Early cartilage and bone erosion is associated with the accumulation of several cell populations in the synovial membrane (SM) and the formation of a proliferating pannus. The synovial sublining layer contains several cell populations including macrophages, T and B lymphocytes, dendritic cells, and polymorphonuclear leukocytes. The lining layer contains large numbers of macrophages and fibroblast-like synoviocytes. The interface between pannus and cartilage is occupied predominantly by activated macrophage populations and synoviocytes capable of secreting destructive proteases in abundance. We have observed that macrophages aggregate preferentially adjacent to the cartilage-pannus junction (CPJ) and express differentiation phenotypes that are absent from the lining layer macrophages of more remote SM. Moreover, in a prospective study, the number of SM macrophages correlated with the degree of joint damage occurring over one year. Similar results were obtained when SM biopsy samples were analyzed and correlated with clinical and radiological changes occurring over 6 years. Macrophages and synoviocytes at the CPJ express matrix metalloproteinase and cathepsin mRNA from the earliest stage of RA. The mechanisms involved in the secretion of tissue degrading enzymes by macrophages and synoviocytes are undergoing further investigation and preliminary results suggest that different regulation pathways may exist.     

The clinical and health status of patients with recent-onset rheumatoid arthritis

This study was designed to document the clinical and health status of patients with recent-onset rheumatoid arthritis (RA). Three groups were studied: 108 patients who had had RA for greater than 1 year (established RA group), 313 patients who had had RA for less than or equal to 1 year (recent-onset RA group), and 188 healthy friend of the patients with recent-onset RA (no RA group). Clinical status was measured using tender joint count, erythrocyte sedimentation rate, and overall physician assessment. Health status was measured using the physical, psychological, pain, and arthritis impact scores of the Arthritis Impact Measurement Scales. Scores on all clinical and health status measures indicated substantial disease effects in the group with recent-onset RA. For most of these measures, effect size analysis indicated that clinical and health status impacts in the recent-onset RA group were similar in magnitude to those found in the groups with more established disease, with scores in both groups being substantially different from those found in the no RA group. These results document the magnitude of the clinical and health status impacts in recent-onset RA. They lend support to recent arguments advocating aggressive therapy earlier in the course of this frequently disabling disease.