Coronary artery disease (CAD) is the leading cause of excess deaths in RA. However, identification of features denoting those with CAD risk is lacking. The composition of circulating mononuclear cell (PBMC) subsets in RA cases differs markedly from healthy controls in extent of T-cell activation with clonal expansion and differentiation to memory effector status and presence of inflammatory monocytes. We sought to evaluate whether elevations in these subpopulations in RA denote those with increased risk for subclinical CAD, as measured by coronary artery calcium (CAC).
72 RA patients underwent cardiac computed tomography to assess CAC. PBMC subsets were determined by multiparameter flow cytometry. Multivariable logistic regression was used to determine the associations between PBMC subpopulations and presence of CAC.
33% had CAC and exhibited significant increases of circulating CD4 T cell subsets denoting activation and differentiation to memory effector phenotypes. Analogous increases in CD8 T cell subsets, and intermediate CD14hiCD16+monocytes, were also present compared to those without CAC. The CD4 and CD8 T cell subset increases were highly intercorrelated, while increases in CD14hiCD16+monocytes were independent of the elevated CD4 subsets. After adjustment for relevant confounders, levels of CD4+CD56+CD57+ T cells and CD14hiCD16+monocytes remained associated with the presence of CAC.
These PBMC subsets are markers for CAC and suggest mechanisms of atherogenesis in RA may operate in part through their increases, raising further questions about the mechanisms underlying the presence of these subset alterations in RA and the potential for shared etiologic pathways between RA and CVD.
Cardiovascular disease (CVD) is a leading cause of death in systemic lupus erythematosus (SLE) and in rheumatoid arthritis (RA). Although only explored in one study, ECG non-specific ST-T abnormalities, in addition to corrected QT-interval (QTc) prolongation, were recently reported in an SLE inception cohort. Importantly, these ECG abnormalities are known predictors of CVD mortality in the general population, yet their prevalence in patients with established SLE has not been evaluated.
We cross-sectionally investigated the presence of non-specific ST-T and QTc abnormalities in 50 patients with SLE, predominantly Hispanic and black, without CVD or SLE-related cardiac involvement and compared them with 139 patients with RA without CVD. Demographics, disease-specific characteristics and CVD risk factors were ascertained and adjusted for.
Patients with SLE (mean age 36±13 years, 92% women, 6 years median disease duration, 96% Hispanics and blacks) had a 3.3-fold higher adjusted prevalence of non-specific ST-T abnormalities (56% vs 17%; p <0.0001) compared with RA, despite the older age and higher percentage of men in the RA group. The QTc was 26 ms longer in SLE compared with RA (p=0.002) in the setting of a higher percentage of women, blacks, Hispanics and higher C reactive protein levels in the SLE group.
This study demonstrates a high prevalence of ECG abnormalities in predominantly Hispanic and black patients with SLE. Longitudinal evaluation of the progression to potentially life-threatening arrhythmias and/or cardiovascular events is warranted.
Cardiovascular Disease; Systemic Lupus Erythematosus; Autoimmune Diseases
To investigate the association between oral calcium supplementation and coronary arterial calcification among rheumatoid arthritis (RA) patients without known cardiovascular disease (CVD).
This study was nested in a prospective cohort study of RA patients without known CVD. Daily supplemental calcium dose was ascertained from prescription and over-the-counter medications at baseline and visit 2 (median 20 months post-baseline). Coronary artery calcium (CAC), a measure of coronary atherosclerosis, was assessed by cardiac multi-detector row computed tomography at baseline and visit 3 (median 39 months post-baseline). The association of calcium supplementation with CAC was explored.
Among the 145 RA patients studied, 42 (28%) took ≥1000mg/day of supplemental calcium at baseline. Forty-four (30%) and 50 (34%) had a CAC score >100 units at baseline and follow-up, respectively. Baseline CAC scores >100 units were significantly less frequent in the higher (≥1000mg/day) supplemental calcium group than in the lower dosed group (<1000mg/day) [OR 0.28 (95% CI 0.11-0.74)]; this remained significant after adjusting for relevant confounders [OR 0.30 (95% CI 0.09-0.93)]. Similarly, at the third study visit, CAC scores >100 units were less frequent in the higher vs. the lower supplemental calcium group [OR 0.41 (95% CI 0.18-0.95)].
When adjusted for relevant confounders, statistical significance was lost [OR 0.39 (95% CI 0.14-1.12)]. No gender interaction and no change in CAC score over time were appreciated.
Higher levels of oral calcium supplementation were not associated with an increased risk of coronary atherosclerosis as measured by CAC score in this RA cohort.
A population-based cohort showed an association between cigarette smoking and subclinical parenchymal lung disease defined as regions of increased computed tomography (CT) lung densitometry. This technique has not been applied to the rheumatoid arthritis (RA) population where associated ILD is highly prevalent. The association between cumulative cigarette smoking and volume of areas of high attenuation (HAA: >-600 and <-250 Hounsfield Units) on full inspiratory CT was compared in 172 RA participants and 3,969 controls in a general population sample. Multivariable regression models were used to adjust for demography, anthropometrics, percent emphysema, and CT parameters. The mean cumulative cigarette smoking exposure was 25 (IQR 10–42) and 15(IQR 5–31) pack-years for the RA and non-RA cohorts, respectively. Mean HAA was 153(±57) cm3 and 129(±50) cm3 in the RA and non-RA cohorts, respectively. Each 10 cigarette pack-year increment was associated with a higher HAA by 0.03% (95% CI, 0.007–0.05%) in RA patients and by 0.008% (95% CI, 0.003–0.01%) in those without RA (interaction p = 0.001). Cigarette smoking was associated with higher lung attenuation; with a magnitude of association more pronounced in those with RA than in the general population. These data suggest that cigarette smoking may be a more potent ILD risk factor for RA patients than in the general population.
To explore the contributions from and interactions between articular swelling and damage, psychosocial factors, and body composition characteristics on walking speed in rheumatoid arthritis (RA).
RA patients underwent the timed 400 meter long-corridor walk. Demographics, self-reported levels of depressive symptoms and fatigue, RA characteristics, and body composition [using whole-body dual-energy X-ray absorptiometry (DXA), and abdominal and thigh computed tomography (CT)] were assessed and their associations with walking speed explored.
A total of 132 RA patients had data for the 400 meter walk, among whom 107 (81%) completed the full 400 meters. Significant multivariable indicators of slower walking speed were older age, higher depression scores, higher reported pain and fatigue, higher swollen and replaced joint counts, higher cumulative prednisone exposure, non-treatment with disease-modifying anti-rheumatic drugs (DMARDs), and worse body composition. These features accounted for 60% of the modeled variability in walking speed. Among specific articular features, slower walking speed was primarily correlated with large/medium lower-extremity joint involvement. However, these articular features accounted for only 21% of the explainable variability in walking speed. Having any relevant articular characteristics was associated with a 20% lower walking speed among those with worse body composition (p<0.001) compared with only a 6% lower speed among those with better body composition (p-value for interaction=0.010).
Psychosocial factors and body composition are potentially reversible contributors to walking speed in RA. Relative to articular disease activity and damage, non-articular indicators were collectively more potent indicators of an individual's mobility limitations.
Mobility; Disability; Prediction; Rheumatoid Arthritis
This review focuses on the genetic features of psoriatic arthritis (PsA) and their relationship to phenotypic heterogeneity in the disease, and addresses three questions: what do the recent studies on human leukocyte antigen (HLA) tell us about the genetic relationship between cutaneous psoriasis (PsO) and PsA – that is, is PsO a unitary phenotype; is PsA a genetically heterogeneous or homogeneous entity; and do the genetic factors implicated in determining susceptibility to PsA predict clinical phenotype? We first discuss the results from comparing the HLA typing of two PsO cohorts: one cohort providing the dermatologic perspective, consisting of patients with PsO without evidence of arthritic disease; and the second cohort providing the rheumatologic perspective, consisting of patients with PsA. We show that these two cohorts differ considerably in their predominant HLA alleles, indicating the heterogeneity of the overall PsO phenotype. Moreover, the genotype of patients in the PsA cohort was shown to be heterogeneous with significant elevations in the frequency of haplotypes containing HLA-B*08, HLA-C*06:02, HLA-B*27, HLA-B*38 and HLA-B*39. Because different genetic susceptibility genes imply different disease mechanisms, and possibly different clinical courses and therapeutic responses, we then review the evidence for a phenotypic difference among patients with PsA who have inherited different HLA alleles. We provide evidence that different alleles and, more importantly, different haplotypes implicated in determining PsA susceptibility are associated with different phenotypic characteristics that appear to be subphenotypes. The implication of these findings for the overall pathophysiologic mechanisms involved in PsA is discussed with specific reference to their bearing on the discussion of whether PsA is conceptualised as an autoimmune process or one that is based on entheseal responses.
The interleukin-6 receptor (IL-6R) blocker tocilizumab (TCZ) reduces inflammatory disease activity in rheumatoid arthritis (RA) but elevates lipid concentrations in some patients. We aimed to characterise the impact of IL-6R inhibition on established and novel risk factors in active RA.
Randomised, multicentre, two-part, phase III trial (24-week double-blind, 80-week open-label), MEASURE, evaluated lipid and lipoprotein levels, high-density lipoprotein (HDL) particle composition, markers of coagulation, thrombosis and vascular function by pulse wave velocity (PWV) in 132 patients with RA who received TCZ or placebo.
Median total-cholesterol, low-density lipoprotein-cholesterol (LDL-C) and triglyceride levels increased in TCZ versus placebo recipients by week 12 (12.6% vs 1.7%, 28.1% vs 2.2%, 10.6% vs −1.9%, respectively; all p<0.01). There were no significant differences in mean small LDL, mean oxidised LDL or total HDL-C concentrations. However, HDL-associated serum amyloid A content decreased in TCZ recipients. TCZ also induced reductions (>30%) in secretory phospholipase A2-IIA, lipoprotein(a), fibrinogen and D-dimers and elevation of paraoxonase (all p<0.0001 vs placebo). The ApoB/ApoA1 ratio remained stable over time in both groups. PWV decreases were greater with placebo than TCZ at 12 weeks (adjusted mean difference 0.79 m/s (95% CI 0.22 to 1.35; p=0.0067)).
These data provide the first detailed evidence for the modulation of lipoprotein particles and other surrogates of vascular risk with IL-6R inhibition. When compared with placebo, TCZ induced elevations in LDL-C but altered HDL particles towards an anti-inflammatory composition and favourably modified most, but not all, measured vascular risk surrogates. The net effect of such changes for cardiovascular risk requires determination.
Cardiovascular Disease; Lipids; Inflammation; Rheumatoid Arthritis; DMARDs (biologic)
Current disease activity measures for systemic lupus erythematosus (SLE) are difficult to score or interpret and problematic for use in clinical practice. Lupus Foundation of America (LFA)-Rapid Evaluation of Activity in Lupus (REAL) is a pilot application composed of anchored visual analogue scores (0–100 mm each) for each organ affected by lupus. This study evaluated the use of LFA-REAL in capturing SLE disease activity.
In a preliminary test of LFA-REAL, this simplified, organ-based system was compared with the most widely used outcome measures in clinical trials, the British Isles Lupus Assessment Group 2004 Index (BILAG), the SLE Disease Activity Index (SLEDAI) and the Safety of Estrogens in Lupus Erythematosus National Assessment (SELENA) SLEDAI Physician's Global Assessment (SS-PGA). The level of agreement was analysed using Spearman rank correlations.
91 patients with SLE with mild to severe disease activity were evaluated, their median SLEDAI score was 4.0 (range 0–28) and BILAG score 8.0 (0–32). The median SS-PGA was 38 mm (4–92) versus the total REAL 50 mm (0–268), which expands in range by additive organ scores. Thirty-three patients had moderate to severe disease activity (≥1.5 on SS-PGA landmarks). The median SS-PGA score of this group was 66 mm (50–92) versus median REAL score of 100 mm (59–268), confirming ability to detect a wider distribution of scores at higher disease activity. Total REAL correlated with SLEDAI, BILAG and SS-PGA (correlation coefficient=0.816, 0.933 and 0.903, respectively; p<0.001 for all). Individual LFA-REAL organ scores for musculoskeletal and mucocutaneous also correlated with corresponding BILAG domain scores (correlation coefficient=0.925 and 0.934, p<0.001).
In this preliminary exercise, there were strong correlations between LFA-REAL and validated lupus disease activity indices. Further development may be valuable for consistent scoring in clinical trials, grading optimal assessment of change in disease activity and reliable monitoring of patients in practice.
Autoimmune Diseases; Systemic Lupus Erythematosus; Autoantibodies
A subset of rheumatoid arthritis (RA) patients have detectable antibodies directed against the peptidyl-arginine deiminase (PAD) enzyme isoforms 3 and 4. Anti-PAD3/4 cross-reactive antibodies (anti-PAD3/4XR) have been shown to lower the calcium threshold required for PAD4 activation, an effect potentially relevant to the pathogenesis of RA-associated interstitial lung disease (ILD).
RA patients underwent multi-detector computed tomography (MDCT) of the chest with interpretation by a pulmonary radiologist for ILD features. A semi-quantitative ILD Score (range 0–32) was calculated. Concurrent serum samples were assessed for antibodies against PAD by immunoprecipitation with radiolabeled PAD3 and PAD4.
Among the 176 RA patients studied, any ILD was observed in 58 (33%) and anti-PAD3/4XR was detected in 19 (11%). The frequency of any ILD among those with anti-PAD3/4XR was 68% vs. 29% among those with no anti-PAD (crude OR = 5.39; p = 0.002) and vs. 27% among those with anti-PAD4 that was not cross-reactive with PAD3 (crude OR = 5.74; p = 0.001). Both associations were stronger after adjustment for relevant confounders (adjusted ORs = 7.22 and 6.61, respectively; both p-values<0.01). Among ever smokers with anti-PAD3/4XR, the adjusted frequency of any ILD was 93% vs. 17% for never smokers without the antibody (adjusted OR = 61.4; p = 0.001, p-value for the interaction of smoking with anti-PAD3/4XR<0.05).
The prevalence and extent of ILD was markedly higher among RA patients with anti-PAD3/4 cross-reactive antibodies, even after accounting for relevant confounders, particularly among ever smokers. These findings may suggest etiopathologic mechanisms of RA-ILD, and their clinical utility for predicting ILD warrants additional study.
Up to 50% of women receiving aromatase inhibitor (AI) complain of AI-associated musculoskeletal symptoms (AIMSS) and 15% discontinue treatment. We conducted a randomized, sham-controlled trial to evaluate whether acupuncture improves AIMSS and to explore potential mechanisms.
Patients and Methods
Postmenopausal women with early stage breast cancer, experiencing AIMSS were randomized to 8 weekly real or sham acupuncture sessions. We evaluated changes in the Health Assessment Questionnaire Disability Index (HAQ-DI) and pain visual analog scale (VAS) following the intervention compared to baseline. Serum estradiol, β-endorphin and proinflammatory cytokine concentrations were measured pre and post-intervention.
We enrolled 51 women, of whom 47 were evaluable, including 23 randomized to real and 24 to sham acupuncture. Baseline characteristics were balanced between groups with the exception of a higher HAQ-DI score in the real acupuncture group (p=0.047). We did not observe a statistically significant difference in reduction of HAQ-DI (p=0.30) or VAS (p=0.31) between the two groups. Following 8 weekly treatments, we observed a statistically significant reduction of IL-17 (p≤0.009) in both groups. No significant modulation was seen in estradiol, β-endorphin, or other proinflammatory cytokine concentrations in either group.
We did not observe a significant difference in AIMSS changes between real and sham acupuncture. As sham acupuncture used in this study may not be equivalent to placebo, further studies with a non-acupuncture arm may be required to establish whether acupuncture is beneficial for the treatment of AIMSS.
Peptidylarginine deiminases (PADs) play a critical role in generating autoantigens in rheumatoid arthritis (RA), but the mechanisms underlying their dysregulation in this disease remain unknown. Although PADs require supraphysiologic concentrations of calcium for activity in vitro, the enzymes are clearly active in vivo (e.g. in RA synovial fluid) where calcium concentrations are much lower. In this study, we have discovered a novel subset of anti-PAD4 autoantibodies (identified by their cross-reactivity with PAD3) which strikingly increase the catalytic efficiency of PAD4 by decreasing the enzyme’s requirement for calcium into the physiologic range. Patients with these novel PAD3/PAD4 cross-reactive autoantibodies had higher baseline radiographic damage scores and a higher likelihood of radiographic progression compared to individuals negative for these antibodies. The ability of autoantibodies to activate an enzyme that itself generates citrullinated autoantigens identifies an important feed-forward loop which may drive the erosive outcome observed in RA patients with these autoantibodies. PAD3 autoantibodies may therefore identify RA patients who would benefit from early aggressive treatment or addition of PAD-inhibitor therapy.
Individuals with rheumatoid arthritis (RA) are at a greater risk for cardiovascular disease (CVD). Vitamin D deficiency is a potential risk factor for CVD and metabolic syndrome. Since patients with RA have a high prevalence of vitamin D deficiency, we investigated the association of vitamin D levels with cardiometabolic risk factors in a cohort of RA patients with no prior history of CVD.
Serum 25(OH)D levels were measured among RA patients enrolled in a cohort study of subclinical CVD. The cross-sectional associations of 25(OH)D level with traditional CVD risk factors, such as insulin resistance [estimated using the Homeostatic Model Assessment (HOMA)], adiopokines, markers of systemic inflammation and endothelial activation were explored, adjusting for pertinent sociodemographic, lifestyle, and RA characteristics.
Among 179 RA patients, 73 (41%) had a 25(OH)D level <30ng/mL. Only 23 patients (13%) had a 25(OH)D level ≥45ng/mL. After adjusting for demographics and BMI, 25(OH)D remained significantly associated with HDL and inversely associated with HOMA-IR, fibrinogen, E-selectin, and s-ICAM. Significant associations with HDL, E-selectin, and s-ICAM were maintained after adjusting for DAS28 and autoantibody status. These associations were similar between groups subdivided by gender, ethnicity, body mass index, DAS28 level and autoantibody status.
These data suggest that vitamin D deficiency is common in RA and may be independently associated with several cardiometabolic intermediates in this population.
In cross-sectional studies, patients with rheumatoid arthritis (RA) have higher coronary artery calcium (CAC) than controls. However, their rate of progression of CAC and the predictors of CAC progression have heretofore remained unknown.
Incidence and progression of CAC were compared in 155 patients with RA and 835 control participants. The association of demographic characteristics, traditional cardiovascular risk factors, RA disease characteristics and selected inflammatory markers with incidence and progression of CAC were evaluated.
The incidence rate of newly detected CAC was 8.2/100 person-years in RA and 7.3/100 person-years in non-RA control subjects [IRR 1.1 (0.7-1.8)]. RA patients who developed newly detectable CAC were older (59±7 vs. 55±6 years old, p=0.03), had higher triglyceride levels (137±86 vs. 97±60 mg/dL, p=0.03), and higher systolic blood pressure (129±17 vs. 117±15 mm Hg, p=0.01) compared to those who did not develop incident CAC. Differences in blood pressure and triglyceride levels remained significant after adjustment for age (p<=0.05). RA patients with any CAC at baseline had a median rate of yearly progression of 21 (7–62) compared to 21 (5–70) Agatston units in controls. No statistical differences between RA progressors and RA non-progressors were observed for inflammatory markers or for RA disease characteristics.
The incidence and progression of CAC did not differ between RA and non-RA participants. In patients with RA, incident CAC was associated with older age, higher triglyceride levels, and higher blood pressure, but not with inflammatory markers or RA disease characteristics.
To explore the associations of thigh computed tomography (CT)-derived measures of body composition with functional outcomes in patients with rheumatoid arthritis (RA).
Patients with RA underwent bilateral mid-femoral quantitative CT for measurement of thigh fat area (TFA), muscle area (TMA), and muscle density (TMD). The associations of thigh composition measures with disability and physical performance, measured with the Health Assessment Questionnaire (HAQ), Valued Life Activities (VLA) scale, and Short Physical Performance Battery (SPPB), were explored for the total cohort and by gender, controlling for pertinent demographic, lifestyle, and RA disease and treatment covariates.
A total of 152 RA patients were studied. Among potential determinants of TMD, higher age, higher duration of sedentary activity, longer RA duration, higher tender joint count, higher serum IL-6 levels, use of glucocorticoids, and non-use of hydroxychloroquine were all significantly associated with lower TMD in multivariable modeling. RA characteristics accounted for 77% of the explainable variability in TMD. When co-modeled, higher TFA and lower TMD, but not lower TMA, were significantly and independently associated with higher HAQ scores, lower SF-36 total physical scores, lower composite SPPB scores, and a greater proportion of affected obligatory VLAs.
Thigh CT-derived measures of body composition, particularly fat area and muscle density, were strongly associated with disability and physical performance in RA patients, with RA disease features as potential determinants. Efforts to reduce fat and improve muscle quality may reduce disability in this population with impaired physical functioning.
Body Composition; Disability; Muscle; Adipose
Adipokines have inflammatory and immunomodulatory properties that may contribute to erosive joint damage. The association of serum adipokine levels with progression of radiographic joint damage in patients with rheumatoid arthritis (RA) was prospectively explored.
Patients with RA underwent serum adipokine assessment (adiponectin, resistin, leptin) at three timepoints and hand/feet x-rays, scored using the Sharp-van der Heijde Score (SHS), at baseline and the third study visit, separated by an average of 39 ± 4 months. The associations of baseline and average adipokine levels with change in SHS were explored, adjusting for pertinent confounders.
Of the 152 patients studied, 85 (56%) showed an increase in SHS (defined as >0 SHS units). Among the adipokines studied, only adiponectin was significantly associated with radiographic progression, with average adiponectin levels more strongly associated than baseline levels. After adjusting for average C reactive protein and baseline SHS, patients in the highest quartile of average adiponectin had a SHS progression rate more than double the lowest quartile (1.00 vs 0.48 units/year; p=0.008). Similarly, those in the highest quartile of adiponectin had a more than fivefold greater odds of any radiographic progression compared with the lowest quartile (OR 5.75; p=0.002). The magnitude of the association of average adiponectin levels with radiographic progression was greater in women, those with body mass index <30 kg/m2 and those receiving baseline biological disease-modifying antirheumatic drugs.
These prospective data provide evidence of temporality and dose-response in the relationship between circulating adiponectin and erosive joint destruction in RA, and highlight subgroups of patients at highest risk for adiponectin-associated radiographic progression.
Despite the recognized risk of accelerated atherosclerosis in patients with rheumatoid arthritis (RA), little is known about cardiovascular risk management in contemporary cohorts of these patients. We tested the hypotheses that major modifiable cardiovascular risk factors were more frequent and rates of treatment, detection, and control were lower in patients with RA than in non-RA controls.
The prevalence of hypertension, diabetes, elevated low-density lipoprotein (LDL) cholesterol, elevated body mass index, smoking, moderate-high 10-year cardiovascular risk and the rates of underdiagnosis, therapeutic treatment, and recommended management were compared in 197 RA patients and 274 frequency-matched control subjects, and their associations with clinical characteristics were examined.
Eighty percent of RA patients and 81% of control subjects had at least 1 modifiable traditional cardiovascular risk factor. Hypertension was more prevalent in the RA group (57%) than in controls [42%, P =0.001]. There were no statistically significant differences in the frequency of diabetes, elevated body mass index, smoking, intermediate-high 10-year coronary heart disease risk, or elevated LDL in patients with RA versus controls. Rates of newly identified diabetes, hypertension, and hyperlipidemia were similar in RA patients versus controls. Rates of therapeutic interventions were low in both groups but their use was associated with well-controlled blood pressure (OR = 4.55, 95% CI: 1.70, 12.19) and lipid levels (OR = 9.90, 95% CI: 3.30, 29.67).
Hypertension is more common in RA than in controls. Other traditional cardiovascular risk factors are highly prevalent, underdiagnosed, and poorly controlled in patients with RA, as well as controls.
rheumatoid arthritis; cardiovascular risk; epidemiology
To define the relationship between autoantigen citrullination and different peptidylarginine deiminase (PAD) enzymes in rheumatoid arthritis (RA).
Citrullinated autoantigens were identified by immunoblotting control and ionomycin-activated human primary neutrophil lysate with RA sera. Autoantigen identity and citrullination sites were defined by mass spectrometry. PAD isoenzyme expression in human neutrophils was determined by immunoblotting. PAD substrate specificity was addressed in HL-60 cell lysates co-incubated with human recombinant PAD2, PAD3 and PAD4.
Although prominent protein citrullination is observed in ionomycin activated neutrophils, RA sera only recognized a limited number of these citrullinated molecules. Among these, we identified that beta and gamma actins are citrullinated on at least ten arginine residues, generating a novel 47kDa species that is frequently recognized by RA autoantibodies. Interestingly, we showed that the PAD enzymes expressed in human neutrophils (i.e. PAD2, PAD3 and PAD4) have unique substrate specificities, independent of their subcellular distribution. Thus, only PAD2 was able to citrullinate native beta/gamma-actin, while histone H3 was only citrullinated by PAD4.
These studies identified beta and gamma actins as novel citrullinated autoantigens in RA, allowing enzyme specificity against intracellular substrates to be addressed. The studies provide evidence that PAD enzymes have the intrinsic capacity to select unique protein targets. We propose that unique PAD specificity may play a role in autoantigen selection in RA.
Citrullination; rheumatoid arthritis; anti-CCP; actin; peptidylarginine deiminase
To explore predictors of change in measures of carotid atherosclerosis among rheumatoid arthritis (RA) patients without known cardiovascular disease (CVD) at baseline
RA patients underwent carotid ultrasonography at two timepoints, separated by an average of 3.2 ± 0.3 years. The associations of baseline and average patient characteristics with the average yearly change in mean maximal intima-medial thickness (IMT) of the common (CCA) and internal carotid arteries (ICA), and with incident or progressive plaque in the ICA/carotid bulb, were explored.
Among the 158 RA patients, maxCCA-IMT increased in 82% (median=16 μm/year; p<0.001) and maxICA-IMT increased in 70% (median=25 μm/year; p<0.001). Incident plaque was observed in 14% without baseline plaque [incidence rate=4.2/100 person-years (95% CI 1.61–6.82)]. Plaque progression was observed in 5% with baseline plaque. Among RA predictors, the adjusted average yearly change in maxCCA-IMT was significantly greater in patients with earlier RA vs. longer disease. Those prescribed TNF inhibitors at baseline had a 37% lower adjusted rate of maxCCA-IMT progression vs. non-users (14 vs. 22 μm/year; p=0.026). For maxICA-IMT, cumulative prednisone exposure was associated with progression [1.2 μm/year per gram (95% CI 0.1–2.4)] after adjustment, and was lower in patients prescribed statins concomitant with prednisone. Higher swollen joint count and higher average CRP were both associated with incident or progressive plaque, primarily in patients with elevated baseline CVD risk based on the Framingham score.
These prospective data provide evidence for inflammation as a contributor to subclinical atherosclerosis progression in RA, potentially modified favorably by TNF inhibitors and detrimentally by glucocorticoids.
Atherosclerosis; Inflammation; prediction; carotid ultrasound
Tissue-infiltrating multinucleated giant cells (MNGs) within geographic necrosis are pathologic hallmarks of granulomatosis with polyangiitis (GPA). However, the origin, phenotype, and function of these cells in GPA remain undefined.
MNG phenotype in GPA lung tissue was examined by immunohistochemistry using antibody directed against cathepsin K and calcitonin-receptor. Tartrate-resistant-acid-phosphatase (TRAP) expression was assessed using enzymatic color reaction. Peripheral blood mononuclear cells (PBMCs) from 13 GPA patients (5 with localized and 8 with systemic disease) and 11 healthy controls were cultured in the presence of RANKL and M-CSF for 9 days, and TRAP+ MNGs containing 3 or more nuclei were identified. GPA lung granulomata contained numerous MNGs that expressed osteoclastic TRAP and cathepsin K but not calcitonin receptors. In the presence of RANKL and M-CSF, PBMCs of GPA patients formed significantly more MNGs than healthy controls (114±29 MNG/well vs. 22±9 MNG/well, P = 0.02). In a subgroup analysis, patients with systemic disease generated significantly more MNGs than patients with localized disease (161±35 MNG/well vs. 39±27 MNG/well, P<0.01) or healthy controls (P<0.01). MNG production did not differ between localized GPA and control subjects (P = 0.96).
MNGs in granulomata in the GPA lung express osteoclastic enzymes TRAP and cathepsin K. GPA patients have a higher propensity to form TRAP+ MNGs from peripheral blood than healthy controls. These data suggest that (i) the tendency to form MNGs is a component of the GPA phenotype itself, and (ii) that lesional MNGs might participate in the destructive process through their proteolytic enzymes.
The aim of this study was to explore the presence and localization of myocardial citrullination in samples from rheumatoid arthritis (RA) patients compared to rheumatic and non-rheumatic disease control groups.
Archived myocardial samples obtained during autopsy from 1995 to 2009 were assembled into four groups: RA; scleroderma; fatal myocarditis; and non-rheumatic disease controls. Samples were examined by immunohistochemistry (IHC) for the presence and localization of citrullination and peptidyl arginine deiminase enzymes (PADs) by a single cardiovascular pathologist blinded to disease group and clinical characteristics.
Myocardial samples from seventeen RA patients were compared with those from fourteen controls, five fatal myocarditis patients, and ten scleroderma patients. Strong citrullination staining was detected exclusively in the myocardial interstitium in each of the groups. However, average and peak anti-citrulline staining was 59% and 44% higher, respectively, for the RA group compared to the combined non-RA groups (P < 0.05 for both comparisons). Myocardial fibrosis did not differ between the groups. In contrast to citrullination, PADs 1 to 3 and 6 were detected in cardiomyocytes (primarily PADs 1 and 3), resident inflammatory cells (primarily PADs 2 and 4), and, to a smaller extent, in endothelial cells and vascular smooth muscle cells. PAD staining did not co-localize with anti-citrulline staining in the interstitium and did not vary by disease state.
Staining for citrullination was higher in the myocardial interstitium of RA compared to other disease states, a finding that could link autoimmunity to the known increase in myocardial dysfunction and heart failure in RA.
Abdominal adiposity, especially visceral adiposity, is an emerging cardiometabolic risk factor. How abdominal fat is distributed in rheumatoid arthritis (RA) and its RA-related determinants have not been explored.
Men and women with RA were compared to non-RA controls from the Multi-Ethnic Study of Atherosclerosis. Participants underwent anthropometric measures and quantification of visceral and subcutaneous fat areas (VFA, SFA) using abdominal computed tomography.
A total of 131 RA patients were compared with 121 controls. Despite similar body mass index and waist circumference between the RA and control groups, the adjusted mean VFA was 45cm2 higher (+51%) for RA vs. control men (p=0.005) but not significantly different by RA status in women. The adjusted mean SFA was 119cm2 higher (+68%) for RA vs. control women (p<0.001) but not significantly different by RA status in men. Elevated VFA (>75th percentile) was associated with a significantly higher adjusted probability of having an elevated fasting glucose, hypertension, or the composite definition of the metabolic syndrome for the RA group compared with controls. Within the RA group, rheumatoid factor seropositivity and higher cumulative prednisone exposure were significantly associated with a higher mean adjusted VFA. Higher C-reactive protein levels and lower Sharp scores were significantly associated with both VFA and SFA.
The distribution of abdominal fat differs significantly by RA status. Higher VFA in men with RA, and the more potent association of VFA with cardiometabolic risk factors in men and women with RA, may contribute to cardiovascular risk in RA populations.
Aromatase inhibitors (AIs) are increasingly used as adjuvant treatment of postmenopausal women with hormone receptor-positive breast cancer. AIs are commonly associated with musculoskeletal symptoms. The primary objective of this study was to describe the musculoskeletal symptoms that developed in the first 100 subjects enrolled who had at least 6 months follow-up.
Women with early stage hormone receptor-positive breast cancer were recruited into a multicenter randomized clinical trial to study the pharmacogenomics of two AIs, exemestane, and letrozole. Patients completed the Health Assessment Questionnaire (HAQ) and Visual Analog Scale (VAS) at baseline, 1, 3, 6, and 12 months to assess changes in function and pain, respectively. Patients were referred for evaluation by a rheumatologist if their HAQ and/or VAS scores exceeded a predefined threshold.
Forty-four of 97 eligible patients (45.4%) met criteria for rheumatologic referral. Three patients were ineligible because of elevated baseline HAQ (2) and failure to initiate AI therapy (1). No baseline characteristics were significantly associated with referral. Median time to onset of symptoms was 1.6 months (range 0.4–10 months). Clinical and laboratory evaluation of patients evaluated by rheumatology suggested that the majority developed either non-inflammatory musculoskeletal symptoms or inflammation localized to tenosynovial structures. Thirteen patients discontinued AI therapy because of musculoskeletal toxicity after a median 6.1 months (range 2.2–13 months).
Musculoskeletal side effects were common in AI-treated patients, resulting in therapy discontinuation in more than 10% of patients. There are no identifiable pre-therapy indicators of risk, and the etiology remains elusive.
Aromatase inhibitor; Arthralgia; Breast cancer; Musculoskeletal symptoms; Rheumatology
Pain is among the most frequently-reported, bothersome, and disabling symptoms described by patients with rheumatoid arthritis, and the experience of pain is partially shaped by catastrophizing, a set of cognitive and emotional pain-related processes. However, other variables may moderate catastrophizing’s influence on the experience of pain. In this study, we investigated a variety of factors that might buffer or magnify catastrophizing’s deleterious consequences among patients with RA.
A total of 185 RA patients were surveyed to determine levels of catastrophizing, pain, general psychological distress, and physical functioning.
Catastrophizing was associated with increased pain severity and psychological distress, and with poorer physical functioning. Some of these relationships were significantly moderated by education and social functioning; among RA patients with above-average social functioning and a college education, minimal relationships of catastrophizing with pain and distress symptoms were observed, while these associations were highly significant (p’s< .001) among patients with lower levels of education or social functioning.
Collectively, educational achievement and positive social interactions may protect against some of the deleterious effects of catastrophizing. The design of future interventions to reduce catastrophizing, or ameliorate its impact on pain outcomes, may benefit from further study of these subgroups of patients.
Pain; Coping; Catastrophizing; Rheumatoid Arthritis; Education
Heart failure is a major contributor to cardiovascular morbidity and mortality in rheumatoid arthritis. However, little is known about myocardial structure and function in this population.
Using cardiac magnetic resonance imaging, measures of myocardial structure and function were assessed in men and women with rheumatoid arthritis enrolled in ESCAPE RA, a cohort study of subclinical cardiovascular disease in rheumatoid arthritis, and compared with controls without rheumatoid arthritis enrolled in the Baltimore cohort of the Multi-Ethnic Study of Atherosclerosis.
Myocardial measures were compared between 75 rheumatoid arthritis patients and 225 matched controls. After adjustment, mean left-ventricular mass was 26 grams lower for the RA group compared to controls (p<0.001), an 18% difference. After similar adjustment, mean left-ventricular ejection fraction, cardiac output, and stroke volume were modestly lower in the rheumatoid arthritis group vs. controls. Mean left-ventricular end-systolic and end-diastolic volumes did not differ by rheumatoid arthritis status. Within the rheumatoid arthritis group, higher levels of anti-CCP antibodies and current use of biologics, but not other disease activity or severity measures, were associated with significantly lower adjusted mean left-ventricular mass, end-diastolic volume, and stroke volume, but not ejection fraction. The combined associations of anti-CCP antibody level and biologic use on myocardial measures were additive, without evidence of interaction.
These findings suggest that the progression to heart failure in RA may occur through reduced myocardial mass rather than hypertrophy. Both modifiable and non-modifiable factors may contribute to lower levels of left-ventricular mass and volume.
myocardial dysfunction; heart failure; inflammation; cardiac imaging
Recent reports have suggested that increasing adiposity may protect against radiographic damage in rheumatoid arthritis. We explored the role of serum adipokines (adiponectin, resistin, leptin) in mediating this association.
RA patients underwent total-body dual-energy absorptiometry for measurement of total and regional body fat and lean mass, abdominal computed tomography for measurement of visceral fat area, and radiographs of the hands and feet scored according to the Sharp-van der Heijde method. Serum levels of adipokines were measured and cross-sectional associations with radiographic damage were explored, adjusting for pertinent confounders. The associations of measures of adiposity with radiographic damage were explored with the introduction of adipokines into multivariable modeling as potential mediators.
Among the 197 patients studied, adiponectin demonstrated a strong association with radiographic damage, with the log Sharp score increasing 0.40 units for each log unit increase in adiponectin (p=0.001) after adjusting for pertinent predictors of radiographic damage. Adiponectin independently accounted for 6.1% of the explainable variability in Sharp score, a proportion comparable to rheumatoid factor and greater than HLA-DRB1 shared epitope alleles or C-reactive protein. Resistin and leptin were not associated with radiographic damage in adjusted models. An inverse association between visceral fat area and radiographic damage was attenuated when adiponectin was modeled as a mediator. The association of adiponectin with radiographic damage was stronger in patients with longer disease duration.
Adiponectin may represent a mechanistic link between low adiposity and increased radiographic damage in RA. Adiponectin modulation may represent a novel strategy for attenuating articular damage.
adipose; body composition; erosion; rheumatoid arthritis; comorbidity