Anti-Inflammatory Effect of High-Density Lipoprotein Blunted by Delivery of Altered MicroRNA Cargo in Patients With Rheumatoid Arthritis

OBJECTIVE

High-density lipoprotein (HDL) has well-characterized anti-atherogenic cholesterol efflux and antioxidant functions. Another function of HDL uncharacterized in rheumatoid arthritis (RA) is its ability to transport microRNAs (miRNAs) between cells and thus alter cellular function. The study's purpose was to determine if HDL-miRNA cargo is altered and affects inflammation in RA.

METHODS

HDL-microRNAs were characterized in 30 RA and 30 control participants by next generation sequencing and quantitative polymerase chain reaction. The most abundant differentially expressed miRNA was evaluated further. The function of miR-1246 was assessed by miRNA mimics, antagomiRs, small interfering RNA knockdown, and luciferase assays. Monocyte-derived macrophages were treated with miR-1246-loaded HDL and unmodified HDL from RA and control participants to measure delivery of miR-1246 and its effect on interleukin-6 (IL-6).

RESULTS

The most abundant miRNA on HDL was miR-1246; it was significantly enriched two-fold on HDL from RA versus control participants. HDL-mediated miR-1246 delivery to macrophages significantly increased IL6 expression 43-fold. miR-1246 delivery significantly decreased DUSP3 1.5-fold and DUSP3 small interfering RNA knockdown increased macrophage IL6 expression. Luciferase assay indicated DUSP3 is a direct target of miR-1246. Unmodified HDL from RA delivered 1.6-fold more miR-1246 versus control participant HDL. Unmodified HDL from both RA and control participants attenuated activated macrophage IL6 expression, but this effect was significantly blunted in RA so that IL6 expression was 3.4-fold higher after RA versus control HDL treatment.

CONCLUSION

HDL-miR-1246 was increased in RA versus control participants and delivery of miR-1246 to macrophages increased IL-6 expression by targeting DUSP3. The altered HDL-miRNA cargo in RA blunted HDL's anti-inflammatory effect.

Elevated transferrin receptor impairs T cell metabolism and function in systemic lupus erythematosus

T cells in systemic lupus erythematosus (SLE) exhibit multiple metabolic abnormalities. Excess iron can impair mitochondria and may contribute to SLE. To gain insights into this potential role of iron in SLE, we performed a CRISPR screen of iron handling genes on T cells. Transferrin receptor (CD71) was identified as differentially critical for TH1 and inhibitory for induced regulatory T cells (iTregs). Activated T cells induced CD71 and iron uptake, which was exaggerated in SLE-prone T cells. Cell surface CD71 was enhanced in SLE-prone T cells by increased endosomal recycling. Blocking CD71 reduced intracellular iron and mTORC1 signaling, which inhibited TH1 and TH17 cells yet enhanced iTregs. In vivo treatment reduced kidney pathology and increased CD4 T cell production of IL-10 in SLE-prone mice. Disease severity correlated with CD71 expression on TH17 cells from patients with SLE, and blocking CD71 in vitro enhanced IL-10 secretion. T cell iron uptake via CD71 thus contributes to T cell dysfunction and can be targeted to limit SLE-associated pathology.

Genome-wide association analyses of common infections in a large practice-based biobank

INTRODUCTION

Infectious diseases are common causes of morbidity and mortality worldwide. Susceptibility to infection is highly heritable; however, little has been done to identify the genetic determinants underlying common infectious diseases. One GWAS was performed using 23andMe information about self-reported infections; we set out to confirm previous loci and identify new ones using medically diagnosed infections.

METHODS

We used the electronic health record (EHR)-based biobank at Vanderbilt and diagnosis codes to identify cases of 12 infectious diseases in white patients: urinary tract infection, pneumonia, chronic sinus infections, otitis media, candidiasis, streptococcal pharyngitis, herpes zoster, herpes labialis, hepatitis B, infectious mononucleosis, tuberculosis (TB) or a positive TB test, and hepatitis C. We selected controls from patients with no diagnosis code for the candidate disease and matched by year of birth, sex, and calendar year at first and last EHR visits. We conducted GWAS using SAIGE and transcriptome-wide analysis (TWAS) using S-PrediXcan. We also conducted phenome-wide association study to understand associations between identified genetic variants and clinical phenotypes.

RESULTS

We replicated three 23andMe loci (p ≤ 0.05): herpes zoster and rs7047299-A (p = 2.6 × 10^-3) and rs2808290-C (p = 9.6 × 10^-3;); otitis media and rs114947103-C (p = 0.04). We also identified 2 novel regions (p ≤ 5 × 10^-8): rs113235453-G for otitis media (p = 3.04 × 10^-8), and rs10422015-T for candidiasis (p = 3.11 × 10^-8). In TWAS, four gene-disease associations were significant: SLC30A9 for otitis media (p = 8.06 × 10^-7); LRP3 and WDR88 for candidiasis (p = 3.91 × 10^-7 and p = 1.95 × 10^-6); and AAMDC for hepatitis B (p = 1.51 × 10^-6).

CONCLUSION

We conducted GWAS and TWAS for 12 infectious diseases and identified novel genetic contributors to the susceptibility of infectious diseases.

Isolevuglandins disrupt PU.1-mediated C1q expression and promote autoimmunity and hypertension in systemic lupus erythematosus

We describe a mechanism responsible for systemic lupus erythematosus (SLE). In humans with SLE and in 2 SLE murine models, there was marked enrichment of isolevuglandin-adducted proteins (isoLG adducts) in monocytes and dendritic cells. We found that antibodies formed against isoLG adducts in both SLE-prone mice and humans with SLE. In addition, isoLG ligation of the transcription factor PU.1 at a critical DNA binding site markedly reduced transcription of all C1q subunits. Treatment of SLE-prone mice with the specific isoLG scavenger 2-hydroxybenzylamine (2-HOBA) ameliorated parameters of autoimmunity, including plasma cell expansion, circulating IgG levels, and anti-dsDNA antibody titers. 2-HOBA also lowered blood pressure, attenuated renal injury, and reduced inflammatory gene expression uniquely in C1q-expressing dendritic cells. Thus, isoLG adducts play an essential role in the genesis and maintenance of systemic autoimmunity and hypertension in SLE.

The non-coding RNA interactome in joint health and disease

Non-coding RNAs have distinct regulatory roles in the pathogenesis of joint diseases including osteoarthritis (OA) and rheumatoid arthritis (RA). As the amount of high-throughput profiling studies and mechanistic investigations of microRNAs, long non-coding RNAs and circular RNAs in joint tissues and biofluids has increased, data have emerged that suggest complex interactions among non-coding RNAs that are often overlooked as critical regulators of gene expression. Identifying these non-coding RNAs and their interactions is useful for understanding both joint health and disease. Non-coding RNAs regulate signalling pathways and biological processes that are important for normal joint development but, when dysregulated, can contribute to disease. The specific expression profiles of non-coding RNAs in various disease states support their roles as promising candidate biomarkers, mediators of pathogenic mechanisms and potential therapeutic targets. This Review synthesizes literature published in the past 2 years on the role of non-coding RNAs in OA and RA with a focus on inflammation, cell death, cell proliferation and extracellular matrix dysregulation. Research to date makes it apparent that 'non-coding' does not mean 'non-essential' and that non-coding RNAs are important parts of a complex interactome that underlies OA and RA.

Plasma miRNAs improve the prediction of coronary atherosclerosis in patients with rheumatoid arthritis

OBJECTIVE

MicroRNAs (miRNAs) regulate gene expression and are disease biomarkers. Rheumatoid arthritis (RA) patients have accelerated atherosclerosis leading to excess cardiovascular morbidity and mortality, but traditional risk factors for cardiovascular risk stratification are inadequate. In the general population, miRNAs improve cardiovascular risk estimation beyond traditional risk factors. Our objective was to develop a miRNA panel that predicts coronary atherosclerosis in RA patients.

METHODS

Plasma small RNA next-generation sequencing (NGS) was performed on 161 RA patients whose Agatston scores for coronary artery calcium were previously measured. Random forest analysis of plasma NGS miRNA expression was used to determine which miRNAs best differentiated between those patients with and without coronary artery calcium. Top predictive miRNAs were assayed by quantitative PCR (qPCR). Elastic net regression was used to develop the most parsimonious models with qPCR-measured miRNA concentrations and clinical variables (age, sex, ACC/AHA 10-year risk score, DAS28 score, and diabetes) separately to predict the presence of coronary artery calcium and high coronary artery calcium. C-statistics were used to assess performance model performance.

RESULTS

The top miRNAs which differentiated those with and without coronary atherosclerosis based on random forest analysis included let-7c-5p, miR-30e-5p, miR-30c-5p, miR-4446-3p, miR-126-5p, miR-3168, miR-425-5p, miR-126-3p, miR-30a-5p, and miR-125a-5p. For coronary artery calcium prediction, addition of all miRNAs except miR-126-3p to clinical factors improved the c-statistic modestly from 0.86 to 0.87. For high coronary artery calcium prediction, addition of all miRNAs except miR-30c-5p to clinical factors improved the c-statistic from 0.75 to 0.80.

CONCLUSION

A plasma miRNA panel improved the prediction of high coronary artery calcium beyond traditional risk factors and RA disease activity. Further evaluation of the miRNA panel for prediction of coronary events in RA is necessary. Key Point • A plasma microRNA panel including let-7c-5p, miR-30a-5p, miR-30e-5p, miR-125a-5p, miR-126-3p, miR-126-5p, miR-425-5p, miR-3168, and miR-4446-3p improved the prediction of high coronary artery calcium beyond clinical factors in patients with rheumatoid arthritis.

A Network Biology Approach to Understanding the Tissue-Specific Roles of Non-Coding RNAs in Arthritis

Discovery of non-coding RNAs continues to provide new insights into some of the key molecular drivers of musculoskeletal diseases. Among these, microRNAs have received widespread attention for their roles in osteoarthritis and rheumatoid arthritis. With evidence to suggest that long non-coding RNAs and circular RNAs function as competing endogenous RNAs to sponge microRNAs, the net effect on gene expression in specific disease contexts can be elusive. Studies to date have focused on elucidating individual long non-coding-microRNA-gene target axes and circular RNA-microRNA-gene target axes, with a paucity of data integrating experimentally validated effects of non-coding RNAs. To address this gap, we curated recent studies reporting non-coding RNA axes in chondrocytes from human osteoarthritis and in fibroblast-like synoviocytes from human rheumatoid arthritis. Using an integrative computational biology approach, we then combined the findings into cell- and disease-specific networks for in-depth interpretation. We highlight some challenges to data integration, including non-existent naming conventions and out-of-date databases for non-coding RNAs, and some successes exemplified by the International Molecular Exchange Consortium for protein interactions. In this perspective article, we suggest that data integration is a useful in silico approach for creating non-coding RNA networks in arthritis and prioritizing interactions for further in vitro and in vivo experimentation in translational research.

Ambulatory blood pressure in patients with systemic lupus erythematosus: Association with markers of immune activation

Objectives: Ambulatory blood pressure monitoring measures 24-hour blood pressure, night-time blood pressure, and impaired dipping of nocturnal blood pressure, parameters that better predict cardiovascular risk than standard office blood pressure measurements. Systemic lupus erythematosus is characterized by immune system hyperactivity, elevated cardiovascular risk and high prevalence of hypertension; however, little is known about ambulatory blood pressure in lupus patients and its relationship to immune activation. Methods: We studied 26 patients with lupus and 26 control subjects. We obtained ambulatory 24-hour blood pressure measurements and report plasma concentrations of 77 markers of immune activation using a multiplex immunoassay and assessed their association with blood pressure measurements. Results: Despite similar office blood pressure measurements in patients with lupus and controls, lupus patients had higher 24-hour systolic [median (interquartile range) 129 (113 - 140) vs. 116 (111 - 121) mmHg, p = 0.03] and diastolic blood pressure [80 (69 - 86) vs. 72 (64 - 75) mmHg, p = 0.006] as well as less nocturnal dipping [7.8% (5.1 - 14.2%) vs. 12.0% (8.1 20.0%)] p = 0.03], compared to controls. In patients with lupus, markers of the innate (monocyte chemotactic protein-3) and adaptive immune systems [CUB domain-containing protein-1 and Interleukin-15 receptor subunit-α,] were associated with nocturnal blood pressure measurements and attenuated nocturnal dipping. In conclusion, 24-hour systolic and diastolic blood pressure was higher and nocturnal blood pressure dipping was attenuated in patients with lupus compared to control subjects. Conclusion: In patients with SLE, nocturnal blood pressure and attenuated nocturnal blood pressure dipping were significantly associated with several innate and adaptive immune system biomarkers.

Circulating microbial small RNAs are altered in patients with rheumatoid arthritis

OBJECTIVES

To determine if plasma microbial small RNAs (sRNAs) are altered in patients with rheumatoid arthritis (RA) compared with control subjects, associated with RA disease-related features, and altered by disease-modifying antirheumatic drugs (DMARDs).

METHODS

sRNA sequencing was performed on plasma from 165 patients with RA and 90 matched controls and a separate cohort of 70 patients with RA before and after starting a DMARD. Genome alignments for RA-associated bacteria, representative bacterial and fungal human microbiome genomes and environmental bacteria were performed. Microbial genome counts and individual sRNAs were compared across groups and correlated with disease features. False discovery rate was set at 0.05.

RESULTS

Genome counts of Lactobacillus salivarius, Anaerobaculum hydrogeniformans, Staphylococcus epidermidis, Staphylococcus aureus, Paenisporosarcina spp, Facklamia hominis, Sphingobacterium spiritivorum, Lentibacillus amyloliquefaciens, Geobacillus spp, and Pseudomonas fluorescens were significantly decreased in the plasma of RA compared with control subjects. Three microbial transfer RNA-derived sRNAs were increased in RA versus controls and inversely associated with disease activity. Higher total microbial sRNA reads were associated with lower disease activity in RA. Baseline total microbial sRNAs were threefold higher among patients who improved with DMARD versus those who did not but did not change significantly after 6 months of treatment.

CONCLUSION

Plasma microbial sRNA composition is altered in RA versus control subjects and associated with some measures of RA disease activity. DMARD treatment does not alter microbial sRNA abundance or composition, but increased abundance of microbial sRNAs at baseline was associated with disease activity improvement at 6 months.

Abstract MP41: A Role Of Isolevuglandins In Systemic Lupus Erythematosus Associated Autoimmunity And Hypertension

Essential hypertension and systemic lupus erythematosus (SLE) are devastating conditions that disproportionately affect women. SLE has heterogeneous manifestations and treatment is limited to the use of non-specific global immunosuppression. Importantly, there is an increased prevalence of hypertension in women with SLE compared to healthy controls. Isolevuglandins (IsoLGs) are oxidation products of fatty acids that form as a result of reactive oxygen species. These molecules adduct covalently to lysine residues of proteins. Adducted proteins are then presented as autoantigens to T-cells resulting in immune cell activation. Previous studies have shown an essential role of IsoLGs in immune cell activation and the development of hypertension in animal models. We hypothesize that isoLGs are important for the development of hypertension and systemic immune activation in SLE. We first examined isoLG adduct accumulation within monocytes of human subjects with SLE compared to healthy controls. By flow cytometry, we found marked accumulation of isoLG adducts within CD14 + monocytes (34.2% ± 12.4% vs 3.81% ± 2.1% of CD14 + , N = 10-11, P <0.05). We confirmed this increase in isoLG adducts by mass spectrometry. To determine a causative role of isoLG adducts in immune activation and hypertension in SLE, we employed the B6.SLE123 and NZBWF1 mouse models of SLE. Animals were treated with the isoLG scavenger 2-hydroxybenzylamine (2-HOBA) or vehicle beginning at 7 weeks and were sacrificed at 32 weeks of age. C57BL/6 and NZW were used as controls. Importantly, treatment with 2-HOBA attenuated blood pressure in both mouse models (systolic BP 136.2 ± 5.6 mmHg for B6.SLE123 vs 120.9 ± 4.46 mmHg for B6.SLE123 +2HOBA; 164.7 ± 24.4 mmHg for NZBWF1 vs 136.9 ± 14.9 mmHg for NZBWF1 +2HOBA, N = 6-8, P < 0.05). Moreover, treatment with 2-HOBA reduced albuminuria and renal injury in the B6.SLE123 model (albumin/creatinine ratio 33.8 ± 2.0 x 10 -2 μg/mg for B6.SLE123 vs 5.5 ± 0.9 x 10 -2 μg/mg for B6.SLE123 +2HOBA, N = 7-9, P < 0.05). Finally, immune cell accumulation in primary and secondary lymphoid organs is significantly attenuated by 2-HOBA. These studies suggest a critical role of isoLG adduct accumulation in both systemic immune activation and hypertension in SLE.

Progressively decreasing plasma high-density lipoprotein cholesterol levels preceding diagnosis of smoldering myeloma

We report a case of disappearing high-density lipoprotein (HDL) syndrome caused by oxidative modification of HDL and by autoantibodies against modified HDL, with subsequent diagnosis of myeloma. An elderly Caucasian man had normal lipid levels with HDL cholesterol (HDL-C) levels in the upper 70 mg/dL range from 1999 to 2003. In 2003, his HDL-C levels began to progressively fall, and by 2011, they were undetectable (<5 mg/dL) when measured with a Beckman Synchron LX auto analyzer. Analyses of the plasma sample from 2011 using ultracentrifugation (Vertical Auto Profile), nuclear magnetic resonance, and Ace EXCEL auto analyzer have shown that HDL-C levels were easily detectable (47-54 mg/dL), although reduced compared with his pre-2003 values. Analyses of his plasma sample from 2011 also showed the presence of lipid-adducted apolipoprotein A1 (apoA1) and high titer of antibodies against the adducted apoA1. Interestingly, a negative correlation between HDL-C levels and the titer of antibodies against apoA1 adducts was found in the control cohort. Finally, we show that in the mouse system, an antibody against apoA1 increases the clearance of HDL from plasma. This case of smoldering myeloma preceded by acquired, severe HDL-C deficiency, likely because of oxidative modifications of the HDL protein leading to the formation of autoantibodies, interference with clinical measurement of HDL-C, and increased plasma clearance of HDL, adds to the list of diagnostic considerations for unexplained HDL-C decreases over time.

Heart Failure Risk Associated With Rheumatoid Arthritis-Related Chronic Inflammation

Background

Inflammation may contribute to incident heart failure (HF). Rheumatoid arthritis (RA), a prototypic inflammatory condition, may serve as a model for understanding inflammation‐related HF risk.

Methods and Results

Using the Vanderbilt University Medical Center electronic health record, we retrospectively identified 9889 patients with RA and 9889 control patients without autoimmune disease matched for age, sex, and race. Prevalent HF at entry into the electronic health record or preceding RA diagnosis was excluded. Incident HF was ascertained using International Classification of Diseases, Ninth Revision (ICD‐9), codes and medications. Over 177 566 person‐years of follow‐up, patients with RA were at 21% greater risk of HF (95% CI, 3–42%) independent of traditional cardiovascular risk factors. Among patients with RA, higher CRP (C‐reactive protein) was associated with greater HF risk (P<0.001), while the anti‐inflammatory drug methotrexate was associated with ≈25% lower HF risk (P=0.021). In a second cohort (n=115) of prospectively enrolled patients with and without RA, we performed proteomics and cardiac magnetic resonance imaging to discover circulating markers of inflammation associated with cardiac structure and function. Artemin levels were higher in patients with RA compared with controls (P=0.009), and higher artemin levels were associated with worse ventricular end‐systolic elastance and ventricular‐vascular coupling ratio (P=0.044 and P=0.031, respectively).

Conclusions

RA, a prototypic chronic inflammatory condition, is associated with increased risk of HF. Among patients with RA, higher levels of CRP were associated with greater HF risk, while methotrexate was associated with lower risk.

Tissue sodium content in patients with systemic lupus erythematosus: association with disease activity and markers of inflammation

OBJECTIVES

Sodium (Na⁺) is stored in the skin and muscle and plays an important role in immune regulation. In animal models, increased tissue Na⁺ is associated with activation of the immune system, and high salt intake exacerbates autoimmune disease and worsens hypertension. However, there is no information about tissue Na⁺ and human autoimmune disease. We hypothesized that muscle and skin Na⁺ content is (a) higher in patients with systemic lupus erythematosus (SLE) than in control subjects, and (b) associated with blood pressure, disease activity, and inflammation markers (interleukin (IL)-6, IL-10 and IL-17 A) in SLE.

METHODS

Lower-leg skin and muscle Na⁺ content was measured in 23 patients with SLE and in 28 control subjects using ²³Na⁺ magnetic resonance imaging. Demographic and clinical information was collected from interviews and chart review, and blood pressure was measured. Disease activity was assessed using the SLE Disease Activity Index (SLEDAI). Plasma inflammation markers were measured by multiplex immunoassay.

RESULTS

Muscle Na⁺ content was higher in patients with SLE (18.8 (16.7-18.3) mmol/L) than in control subjects (15.8 (14.7-18.3) mmol/L; p < 0.001). Skin Na⁺ content was also higher in SLE patients than in controls, but this difference was not statistically significant. Among patients with SLE, muscle Na⁺ was associated with SLEDAI and higher concentrations of IL-10 after adjusting for age, race, and sex. Skin Na⁺ was significantly associated with systolic blood pressure, but this was attenuated after covariate adjustment.

CONCLUSION

Patients with SLE had higher muscle Na⁺ content than control subjects. In patients with SLE, higher muscle Na⁺ content was associated with higher disease activity and IL-10 concentrations.

The Endogenous Plasma Small RNAome of Rheumatoid Arthritis

OBJECTIVE

Small RNA (sRNA) sequencing has revealed new sRNA classes beyond microRNAs (miRNAs). These sRNAs can regulate genes and act as biomarkers. The aim of this study was to determine if the endogenous plasma sRNA landscape is altered in patients with rheumatoid arthritis (RA) compared with control subjects and to determine its association with disease-related parameters in RA.

METHODS

sRNA sequencing was performed on plasma from 165 RA and 90 control subjects who were frequency-matched for age, race, and sex. Endogenous sRNAs, such as miRNAs, isomiRs, sRNAs derived from small nuclear RNAs (snDRs), small nucleolar RNAs (snoDRs), Y RNAs (yDRs), transfer-derived RNAs (tDRs), long noncoding RNAs (lncDRs) as well as miscellaneous sRNAs (miscRNAs), were quantified using Tools for Integrative Genome analysis of Extracellular sRNAs (TIGER). Individual and categories of sRNAs were compared between RA and controls, and significantly altered sRNAs and sRNA categories were correlated with disease activity and general laboratory measures in RA.

RESULTS

Patients with RA had more miRNAs (1.42-fold, P = 0.01), more tDRs (1.14-fold, P = 0.04), and fewer yDRs (-1.41-fold, P = 0.009) compared with control subjects. Disease duration was inversely associated with yDRs. Disease-related parameters, such as Disease Activity Score-28 (DAS28), swollen joint count, and inflammatory markers were significantly positively associated with tDRs and miscRNAs, and miR-22-3p and related sequences and isomiRs were most significantly associated with DAS28.

CONCLUSION

Endogenous plasma sRNAs are altered in RA compared with control subjects. Although individual miRNAs have been well studied and many are excellent biomarkers in RA, several non-miRNA sRNAs were significantly associated with disease-related parameters as classes and may represent novel biomarkers for RA.

Development and Validation of a MicroRNA Panel to Differentiate Between Patients with Rheumatoid Arthritis or Systemic Lupus Erythematosus and Controls

OBJECTIVE

MicroRNA (miRNA) are short noncoding RNA that regulate genes and are both biomarkers and mediators of disease. We used small RNA (sRNA) sequencing and machine learning methodology to develop an miRNA panel to reliably differentiate between rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) and control subjects.

METHODS

Plasma samples from 167 RA and 91 control subjects who frequency-matched for age, race, and sex were used for sRNA sequencing. TIGER was used to analyze miRNA. DESeq2 and random forest analyses were used to identify a prioritized list of miRNA differentially expressed in patients with RA. Prioritized miRNA were validated by quantitative PCR, and lasso and logistic regression were used to select the final panel of 6 miRNA that best differentiated RA from controls. The panel was validated in a separate cohort of 12 SLE, 32 RA, and 32 control subjects. Panel efficacy was assessed by area under the receiver operative characteristic curve (AUC) analyses.

RESULTS

The final panel included miR-22-3p, miR-24-3p, miR-96-5p, miR-134-5p, miR-140-3p, and miR-627-5p. The panel differentiated RA from control subjects in discovery (AUC = 0.81) and validation cohorts (AUC = 0.71), seronegative RA (AUC = 0.84), RA remission (AUC = 0.85), and patients with SLE (AUC = 0.80) versus controls. Pathway analysis showed upstream regulators and targets of panel miRNA are associated with pathways implicated in RA pathogenesis.

CONCLUSION

An miRNA panel identified by a bioinformatic approach differentiated between RA or SLE patients and control subjects. The panel may represent an autoimmunity signature, perhaps related to inflammatory arthritis, which is not dependent on active disease or seropositivity.

The role of microRNA-22 in the dysregulation of lupus Tregs and the pathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease affecting over 1.5 million Americans and at least 5 million individuals worldwide. Evidence demonstrates autoantibody producing B cells and dysfunctional CD4+T cells contribute to SLE pathology, however lack of understanding surrounding mechanisms of disease pathogenesis have prevented therapeutic advancement. Studies indicate one mechanism for dysregulated immune homeostasis in autoimmunity is through microRNAs (miRNAs). MiRNAs are short, endogenous post-transcriptional regulators of gene expression which act by degradation or translation repression of target mRNAs. Our group previously identified miR-22-3p as being increased three-fold in SLE patient plasma compared to age- and gender-matched heathy controls. MiR-22-3p levels were increased in whole CD4+T cells (four-fold) and Tregs (three-fold) from B6.SLE1.2.3 mice compared to B6 controls, and inhibition of miR-22-3p, using locked-nucleic acid (LNA)-22 ameliorated key disease pathologies including glomerulonephritis. There was also a 10% reduction in IFN-g+CD4+T cells in mice treated with LNA-22. Based on these data, we hypothesized increased miR-22-3p levels in SLE T cells propagated inflammation directly by skewing naïve CD4+T cells towards the Th1 phenotype during polarization, or indirectly by reducing the regulatory capacity of Tregs. Results show miR-22-3p deficiency is not sufficient to prevent the polarization of Th1 cells. However, inhibition of miR-22-3p in vivo increases Treg IL-10 production, suggesting heightened levels of miR-22-3p may alter their function. We conclude that miR-22-3p overexpression in Tregs indirectly contributes to autoimmune T cell dysregulation in SLE.

Abstract 396: A Unique Case of Artefactual and Real HDL Disappearance Due to Isolevuglandins Adducts

We report a case of acquired, progressive, and severe HDL cholesterol (HDL-C) deficiency that emerged in an individual with multiple myeloma. An 81 year-old white male presented with extremely low HDL-c (≤5 mg/dL). Between the ages of 69 - 73 years old, his annual lipid panels demonstrated HDL-c >70 mg/dL. At that point, his HDL-C levels progressively decreased until their virtual disappearance over a period of 12 years. During this time, he developed anemia, an IgG-kappa M-spike, and increased plasma cells on bone marrow biopsy, compatible with a diagnosis of multiple myeloma. Review of his medications, medical history, and metabolic status failed to identify a cause for his progressive decine of HDL-C. Parallel analyses of plasma samples using detergent to solubilize and release HDL-associated cholesterol (SYNCHRO LX, Beckman) and separation of non-HDL precipitated by dextran sulfate yielded HDL-C values of 5 mg/dL and 47 mg/dL, respectively. Furthermore, HDL-C levels of 52 mg/dL and 54 mg/dL were confirmed using ultracentrifugation and NMR-based methods, respectively. Serum apoAI concentration was 153 mg/dL, suggesting normal levels of HDL, in contrast with the ultra-low HDL-C reported in one method. The patient’s alpha migrating band on lipoprotein gel electrophoresis also appeared normal, suggesting the presence of roughly normal amounts of HDL. Methodological artifact alone, however, did not explain the significant “real” decrease in HDL-C (from the upper 70’s mg/dL to the 40’s mg/dL) recorded during 12 years of monitoring. Isolevuglandins (IsoLG) are highly reactive ketoaldehydes that interact with lysine residues of proteins and head groups of phosphatidylethanolamine. It was recently proposed that IsoLG adducts on HDL can result in deleterious structural and functional changes in the particle. Interestingly, the patient’s serum showed high titers of autoantibodies to IsoLG-apoAI, but low titers against native apoAI. We further studied the turnover of IsoLG-apoAI and native apoAI in mice. This case of artefactual and real HDL-C disappearance in a patient with multiple myeloma is likely due to paraprotein-related interference of HDL-C assays and increased plasma clearance of modified apoA1.

Abstract 415: HDL-small RNA Gene Regulatory Networks Alter T Cell Signalling

Small non-coding RNAs (sRNA) are critical regulators of adaptive immunity and the flow of information between immune cells likely extends beyond cytokines and danger signals to sRNAs. microRNAs (miRNA) are sRNAs that post-transcriptionally regulate gene expression and are transferred between cells within intercellular communication networks. In addition to miRNAs, another class of sRNAs has emerged as critical regulators of gene expression - tRNA-derived small RNAs (tDRs). During cell stress, parent tRNAs are cleaved by RNaseIII enzymes, e.g. Angiogenin (ANG), and tDRs suppresses protein synthesis and gene expression; however, the functional relevance of ANG and tDRs in T cell activation is unknown. To determine if ANG is altered during T cell activation, ANG expression was quantified in anti-CD3 and anti-CD28 activated human CD4+ T cells, and we found that both mRNA and protein levels were significantly ( p <0.05) increased compared to non-activated T cells by real-time PCR and ELISA, respectively. Strikingly, 12 T cell tDRs were significantly upregulated ( p <0.05) during activation, as quantified by high-throughput sRNA sequencing (sRNA-seq). In addition, tDR-GlyGCC was found to be readily exported from CD4+ T cells to HDL after 24 hr post-activation. Moreover, sRNA-seq analysis showed that tDRs (e.g. tDR-GlyGCC) are highly abundant on human HDL. Based on these results, we hypothesized that HDL mediates T cell-originating tDR intercellular communication networks. In support, we found that HDL transferred tDR-GlyGCC from T cells to monocytes, as evidenced by an 18-fold increase ( p <0.05) in tDR-GlyGCC in recipient cells. In conclusion, we demonstrate that HDL facilitates a novel intercellular communication network of tDRs between immune cells which is likely enhanced during T cell activation.

Absence of Fibrosis and Inflammation by Cardiac Magnetic Resonance Imaging in Rheumatoid Arthritis Patients with Low to Moderate Disease Activity

OBJECTIVE

The prevalence of heart failure is increased 2-fold in patients with rheumatoid arthritis (RA); this is not explained by ischemic heart disease or other risk factors for heart failure. We hypothesized that in patients with RA without known heart disease, cardiac magnetic resonance imaging (cMRI) would detect altered cardiac structure, function, and fibrosis.

METHODS

We performed 1.5-T cMRI in 59 patients with RA and 56 controls frequency-matched for age, race, and sex, and compared cMRI indices of structure, function, and fibrosis [late gadolinium enhancement (LGE), native T1 mapping, and extracellular volume (ECV)] using Mann-Whitney U tests and linear regression, adjusting for age, race, and sex.

RESULTS

Most patients with RA had low to moderate disease activity [28-joint count Disease Activity Score-C-reactive protein median 3.16, interquartile range (IQR) 2.03-4.05], and 49% were receiving anti-tumor necrosis factor agents. Left ventricular (LV) mass, LV end-diastolic and -systolic volumes indexed to body surface area, and LV ejection fraction and left atrial size were not altered in RA compared to controls (all p > 0.05). Measures of fibrosis were not increased in RA: LGE was present in 2 patients with RA and 1 control subject; native T1 mapping was similar comparing RA and control subjects, and ECV (median, IQR) was lower (26.6%, 24.7-28.5%) in patients with RA compared to control subjects (27.5%, 25.4-30.4%, p = 0.03).

CONCLUSION

cMRI measures of cardiac structure and function were not significantly altered, and measures of fibrosis were similar or lower in RA patients with low to moderate disease activity compared to a matched control group.

Association between urinary sodium and potassium excretion and blood pressure and inflammation in patients with rheumatoid arthritis

Hypertension is highly prevalent in patients with rheumatoid arthritis (RA). In other populations, high sodium (Na⁺) and low potassium (K⁺) intake are associated with an increased risk of hypertension, and in animal models, a high salt intake exacerbated arthritis. Patients with RA have many comorbidities associated with salt sensitivity, but their salt intake and its relationship to blood pressure and inflammation is unknown. Using the Kawasaki formula, Na⁺ and K⁺ urinary excretion (reflecting intake) was estimated in 166 patients with RA and 92 controls, frequency matched for age, sex, and race. Inflammatory markers and disease activity were measured in RA patients. We tested the associations between blood pressure and Na⁺ and K⁺ excretion. Estimated 24-h Na⁺ excretion was similarly high in both RA (median [IQR] 5.1 g, [3.9-6.6 g]) and controls (4.9 g, [4.0-6.5 g]), p = 0.9, despite higher rates of hypertension in RA (54 vs. 39%, p = 0.03). The Na⁺:K⁺ excretion ratio was significantly higher in RA (2.0 [1.6-2.4]) vs. 1.7 [1.5-2.1]), p = 0.02] compared to controls. In RA, a lower K⁺ excretion was inversely correlated with diastolic blood pressure (adjusted β = - 1.79, p = 0.04). There was no significant association between Na⁺ or K⁺ excretion and inflammatory markers. Despite a similar Na⁺ excretion, patients with RA had higher rates of hypertension than controls, a finding compatible with increased salt sensitivity. Patients with RA had a lower Na⁺:K⁺ excretion ratio than controls, and lower K⁺ excretion was associated with higher diastolic blood pressure in RA.

Effect of Drug Therapy on Net Cholesterol Efflux Capacity of High-Density Lipoprotein-Enriched Serum in Rheumatoid Arthritis

OBJECTIVE

Patients with rheumatoid arthritis (RA) have an increased risk of coronary heart disease (CHD). Some RA therapies may modify this risk, but the underlying mechanisms are unclear. The cholesterol efflux capacity of high-density lipoprotein (HDL) is associated with a reduced CHD risk in non-RA populations; however, inflammation may impair the function of HDL. The aim of this study was to evaluate whether reduced inflammation resulting from treatment with methotrexate (MTX), adalimumab (ADA), or tocilizumab (TCZ) would increase the net cholesterol efflux capacity of HDL in patients with RA.

METHODS

A longitudinal multicenter study repository (Treatment Efficacy and Toxicity in Rheumatoid Arthritis Database and Repository) provided clinical information for and serum samples from 70 patients with RA before and 6 months after starting treatment with a new drug (MTX [n = 23], ADA [n = 22], or TCZ [n = 25]). Disease activity was measured using the Disease Activity Score in 28 joints using the erythrocyte sedimentation rate (DAS28-ESR). The net cholesterol efflux capacity was measured in paired serum samples using THP-1 macrophages, and total cellular cholesterol was measured by fluorometric assay.

RESULTS

The DAS28-ESR decreased with all treatments (P < 0.001). Net cholesterol efflux capacity was not significantly changed after 6 months of new RA therapy (mean ± SD 36.9 ± 17.3% units at baseline versus 38.0% ± 16.9% units at 6 months [P = 0.58]). However, change in net cholesterol efflux capacity was associated with change in the DAS28-ESR (ρ = -0.25, P = 0.04). In a post hoc analysis of patients with impaired net cholesterol efflux capacity at baseline, treatment with TCZ resulted in significant improvement in net cholesterol efflux capacity (21.9 ± 14.7% units at baseline versus 31.3% ± 12.8% units at 6 months [P < 0.02]), but this was not observed with MTX or ADA.

CONCLUSION

Net cholesterol efflux capacity of HDL cholesterol did not change significantly after 6 months of new RA therapy, except in patients with impaired baseline cholesterol efflux capacity who were receiving TCZ. Change in disease activity was associated with change in the net cholesterol efflux capacity.

Net cholesterol efflux capacity of HDL enriched serum and coronary atherosclerosis in rheumatoid arthritis

BACKGROUND/OBJECTIVES

Cardiovascular (CV) risk is increased in patients with rheumatoid arthritis (RA), but not fully explained by traditional risk factors such as LDL and HDL cholesterol concentrations. The cholesterol efflux capacity of HDL may be a better CV risk predictor than HDL concentrations. We hypothesized that HDL's cholesterol efflux capacity is impaired and inversely associated with coronary atherosclerosis in patients with RA.

METHODS

We measured the net cholesterol efflux capacity of apolipoprotein B depleted serum and coronary artery calcium score in 134 patients with RA and 76 control subjects, frequency-matched for age, race and sex. The relationship between net cholesterol efflux capacity and coronary artery calcium score and other clinical variables of interest was assessed in patients with RA.

RESULTS

Net cholesterol efflux capacity was similar among RA (median [IQR]: 34% removal [28, 41%]) and control subjects (35% removal [27%, 39%]) (P=0.73). In RA, increasing net cholesterol efflux capacity was not significantly associated with decreased coronary calcium score (OR=0.78 (95% CI 0.51-1.19), P=0.24, adjusted for age, race and sex, Framingham risk score and presence of diabetes). Net cholesterol efflux capacity was not significantly associated with RA disease activity score, C-reactive protein, urinary F₂-isoprostanes, or degree of insulin resistance in RA.

CONCLUSIONS

Net cholesterol efflux capacity is not significantly altered in patients with relatively well-controlled RA nor is it significantly associated with coronary artery calcium score.

Telomere Length and Coronary Atherosclerosis in Rheumatoid Arthritis

OBJECTIVE

Telomeres protect against chromosomal end damage and shorten with each cell division; their length may be a marker of cardiovascular and overall biological aging. We examined the hypothesis that reduced telomere length is associated with increased coronary atherosclerosis in rheumatoid arthritis (RA).

METHODS

We performed a cross-sectional study in 145 patients with RA and 87 control subjects frequency-matched for age, race, and sex. Coronary artery calcium score was determined by noncontrast cardiac computed tomography. Telomere length was measured from whole blood DNA, using real-time quantitative polymerase chain reaction and expressed as telomeric product to a single-copy gene product ratio (T/S ratio). Associations between telomere length, coronary artery calcium score, and 28-joint Disease Activity Score (DAS28) were assessed with Spearman correlation, proportional odds logistic regression, and linear regression, adjusting for age, race, and sex.

RESULTS

Telomere length was significantly inversely correlated with age in patients with RA (ρ = -0.37, p < 0.001) and control subjects (ρ = -0.39, p = 0.001). Among patients with RA, for every interquartile range (IQR) decrease in telomere length (T/S ratio), the odds of higher coronary artery calcium score increased by 38% (95% CI: 4-60) after adjusting for age, race, and sex (p adjusted = 0.03). Telomere length was not associated with DAS28 (p adjusted = 0.17). Telomere length was not significantly different in patients with RA [median (IQR): 1.02 units (0.9-1.11)] compared to control subjects [1.05 units (0.95-1.17); p = 0.10].

CONCLUSION

Telomere length is inversely associated with coronary artery calcium score, independent of age, race, and sex in patients with RA.

Abstract 193: HDL-Small RNA Intercellular Communication in Systemic Lupus Erythematosus

Extracellular small non-coding RNAs (sRNAs) are a new class of disease biomarkers and are transferred between cells by high-density lipoproteins (HDL) in a novel form of intercellular communication. In chronic inflammatory states and auto-immunity, HDL can become dysfunctional, likely through alterations in its diverse cargo, including changes to sRNA signatures. We have previously found that HDL-microRNAs (miRNA) are altered in systemic lupus erythematosus (SLE); however, miRNAs are just one type of sRNAs. As such we hypothesized that changes to HDL-sRNA cargo and cell-to-cell communication in SLE extend beyond miRNAs. To test this hypothesis, HDL was isolated from SLE and control (n=6-8) subjects by density-gradient ultracentrifugation followed by size-exclusion chromatography. High-throughput sRNA sequencing of HDL demonstrated that tRNA-derived sRNAs (tDRs) were the most abundant class of sRNAs on HDL and were significantly altered in SLE subjects compared to controls (26 up, 10 down). In addition, circulating levels of angiogenin, an RNaseIII enzyme capable of cleaving parent tRNAs into tDRs, was also significantly ( P <0.05) increased in SLE plasma. To determine if tDRs are altered in CD4+ T cells in SLE subjects, real-time PCR was used to quantify candidate tDRs, and we found that tDR-GlyGCC levels were significantly increased 4.2-fold in SLE ( P <0.01). Most importantly, we found that T cells exported tDR-GlyGCC to HDL. To determine if T cell exported tDR-GlyGCC is transferred to other cells by HDL, ex vivo studies were completed using Trans-PhotoActivatable-Ribonucleoside-CrossLinking-ImmunoPrecipitation high-throughput Sequencing (Trans-PAR-CLIPseq) to trace sRNAs from human CD4+ T cells to HDL and then to recipient CD14+ monocytes and CD19+ B-cells. Using this approach, we found a cassette of T cell originating sRNAs, including tDR-GlyGCC, transferred by HDL to recipient B cells and monocytes and loaded onto RNA-Induced Silencing Complexes (RISC) targeting genes associated with inflammation. Here, we demonstrate that HDL facilitates the intercellular transfer of sRNAs between immune cells and these sRNAs are altered in SLE. This altered communication may contribute to T cell imbalance and B cell activation observed in SLE.

High-density lipoprotein function in rheumatoid arthritis

PURPOSE OF REVIEW

Patients with rheumatoid arthritis (RA) have accelerated atherosclerosis despite the appearance of having a less atherogenic lipid profile; however, lipoprotein function rather than concentration may be a better indicator of atherosclerotic risk. The purpose of this review is to summarize recent findings concerning HDL function in patients with RA.

RECENT FINDINGS

Two major activities of HDL, its antioxidant and cholesterol efflux functions have been examined in RA. HDL antioxidant capacity is inversely associated with inflammation and RA disease activity; however, there is no clear consensus if antioxidant capacity is altered significantly in RA compared with control study participants. Moreover, despite numerous studies there is no consensus whether HDL cholesterol efflux capacity is significantly altered in RA compared with control study participants or influenced by inflammation or disease activity.

SUMMARY

Additional studies will be valuable to consolidate existing data and find consensus. Moreover, studies evaluating the impact of various HDL functions on cardiovascular disease in RA are needed.

GlycA, a novel marker of inflammation, is elevated in systemic lupus erythematosus

BACKGROUND

GlycA is a novel marker of systemic inflammation detected by nuclear magnetic resonance (NMR) spectroscopy. In the general population, GlycA is correlated with inflammatory markers such as C-reactive protein (CRP) and associated with coronary heart disease and diabetes. The utility of GlycA in patients with systemic lupus erythematosus (SLE) has not been defined. Therefore, we tested the hypothesis that GlycA concentrations are elevated in patients with SLE and associated with other markers of inflammation and coronary atherosclerosis.

METHODS

We compared concentrations of GlycA, detected by NMR, in 116 patients with SLE and 84 control subjects frequency-matched for age, sex, and race. SLE disease activity index (SLEDAI) and the SLE Collaborating Clinics damage index (SLICC) were calculated. Acute phase reactants, a panel of cytokines, and a lipid panel were measured. Electron beam computer tomography (EBCT) was used to quantify coronary artery calcification, a measure of coronary artery atherosclerosis.

RESULTS

Patients with SLE had higher concentrations of GlycA (398 (350-445)) than control subjects (339 (299-391)) µmol/L, p < 0.001. In patients with SLE, concentrations of GlycA were significantly associated with sedimentation rate (rho = 0.43), C-reactive protein (rho = 0.59), e-selectin (rho = 0.28), intracellular adhesion molecule-1 (rho = 0.30), triglycerides (rho = 0.45), all p < 0.0023 to account for multiple comparisons, but not with creatinine, SLEDAI, SLICC, or coronary calcium scores.

CONCLUSIONS

Concentrations of GlycA are higher in patients with SLE than control subjects and associated with markers of inflammation but not with SLE disease activity or chronicity scores or coronary artery calcification.

Utility of Select Plasma MicroRNA for Disease and Cardiovascular Risk Assessment in Patients with Rheumatoid Arthritis

OBJECTIVE

MicroRNA (miRNA) are small noncoding RNA that posttranscriptionally regulate gene expression and serve as potential mediators and markers of disease. Recently, plasma miR-24-3p and miR-125a-5p concentrations were shown to be elevated in rheumatoid arthritis (RA) and useful for RA diagnosis. We assessed the utility of 7 candidate plasma miRNA, selected for biological relevance, for RA diagnosis and use as markers of disease activity and subclinical atherosclerosis in RA.

METHODS

The cross-sectional study included 168 patients with RA and 91 control subjects of similar age, race, and sex. Plasma concentrations of miR-15a-5p, miR-24-3p, miR-26a-5p, miR-125a-5p, miR-146a-5p, miR-155-5p, and miR-223-3p were measured by quantitative PCR. Utility of plasma miRNA concentrations for RA diagnosis was assessed by area under the receiver-operating characteristic curve (AUROC). Associations between plasma miRNA concentrations and RA disease activity and coronary artery calcium score were assessed by Spearman correlations.

RESULTS

Plasma concentrations of miR-15a-5p, miR-24-3p, miR-26a-5p, miR-125a-5p, miR-146a-5p, miR-155-5p, and miR-223-3p were significantly increased in patients with RA. The highest AUROC for diagnosis of RA (AUROC = 0.725) was found in miR-24-3p, including among rheumatoid factor-negative patients (AUROC = 0.772). Among all patients with RA, the combination of miR-24-3p, miR-26a-5p, and miR-125a-5p improved the model modestly (AUROC = 0.747). One miRNA, miR-155-5p, was weakly inversely associated with swollen joint count (p = 0.024), but no other miRNA were associated with disease activity or coronary artery calcium score.

CONCLUSION

The combination of miR-24-3p, miR-26a-5p, and miR-125a-5p had the strongest diagnostic accuracy for RA. Candidate miRNA had little or no association with RA disease activity or subclinical atherosclerosis.

Insulin resistance is associated with increased concentrations of NT-proBNP in rheumatoid arthritis: IL-6 as a potential mediator

We examined the hypothesis that insulin resistance (IR) decreases circulating concentrations of N-terminal (NT)-probrain natriuretic peptide (BNP). Obesity, despite being a risk factor for heart failure (HF), is paradoxically associated with lower concentrations of BNP, a marker of myocardial stress. Low BNP in obesity is postulated to be due to IR; however, it has been difficult to define the role of IR independent of obesity. IR in rheumatoid arthritis (RA) is increased, independent of obesity, thus allowing potential mechanistic insights into the relationship between IR and BNP. We measured demographic factors, traditional cardiovascular risk factors, body mass index (BMI), markers of inflammation (interleukin-6 (IL-6), C-reactive protein (CRP), tumor necrosis factor α (TNFα)), NT-proBNP, and IR by the homeostatic model assessment (HOMA) in 140 patients with RA and 82 control subjects. Patients with heart failure and coronary artery disease were excluded. We used multiple linear regression models to examine the relationship between HOMA and NT-proBNP in RA and controls and in RA alone, the additional effect of inflammation. As previously reported, NT-proBNP concentrations were higher in RA (median 80.49 pg/mL, IQR (23.67-167.08 pg/mL)) than controls (17.84 pg/mL (3.28-36.28 pg/mL)) (P < 0.001), and the prevalence of IR, defined by HOMA > 2.114, was higher among RA than controls (53 % vs. 15%, P > 0.001). HOMA was positively correlated with NT-proBNP (rho = 0.226, P = 0.007) in RA, but not in controls (rho = -0.154, P = 0.168). In a multivariable model adjusted for age, race, and sex, we found that increasing HOMA was statistically associated with increasing NT-proBNP concentrations in RA (P = 0.001), but not controls (P = 0.543) (P for interaction = 0.036). In RA subjects, when IL-6 was further included in the model, IL-6 (P = 0.0014), but not HOMA (P = 0.43), remained significantly associated with NT-proBNP, suggesting that IL-6 may be mechanistically involved in the relationship between IR and NT-proBNP in RA. We conclude that in patients with RA, insulin resistance is associated with higher, rather than the expected lower, concentrations of NT-proBNP and that this may be related to increased IL-6.

Utility of a novel inflammatory marker, GlycA, for assessment of rheumatoid arthritis disease activity and coronary atherosclerosis

Introduction

GlycA is a novel inflammatory biomarker measured using nuclear magnetic resonance (NMR). Its NMR signal primarily represents glycosylated acute phase proteins. GlycA was associated with inflammation and development of cardiovascular disease in initially healthy women. We hypothesized that GlycA is a biomarker of disease activity and is associated with coronary artery atherosclerosis in patients with rheumatoid arthritis (RA).

Methods

We conducted a cross-sectional study of 166 patients with RA and 90 control subjects. GlycA was measured from an NMR signal originating from N-acetylglucosamine residues on circulating glycoproteins. The relationship between GlycA and RA disease activity (Disease Activity Score based on 28 joints (DAS28)) and coronary artery calcium score was determined.

Results

GlycA concentrations were higher in patients with RA (median (interquartile range): 398 μmol/L (348 to 473 μmol/L)) than control subjects (344 μmol/L (314 to 403 μmol/L) (P < 0.001). In RA, GlycA was strongly correlated with DAS28 based on erythrocyte sedimentation rate (DAS28-ESR) and DAS28 based on C-reactive protein (DAS28-CRP) and their components, including tender and swollen joint counts, global health score, ESR and CRP (all P < 0.001). The area under the receiver operating characteristic curve for GlycA’s ability to differentiate between patients with low versus moderate to high disease activity based on DAS28-CRP was 0.75 (95 % confidence interval (CI): 0.68, 0.83). For each quartile increase in GlycA, the odds of having coronary artery calcium increased by 48 % (95 % CI: 4 %, 111 %), independent of age, race and sex (P = 0.03).

Conclusion

GlycA is a novel inflammatory marker that may be useful for assessment of disease activity and is associated with coronary artery atherosclerosis in patients with RA.

Urinary albumin excretion is increased in patients with rheumatoid arthritis and associated with arterial stiffness

OBJECTIVE

Rheumatoid arthritis (RA) is associated with increased risk of cardiovascular disease (CVD). High urinary albumin excretion is a risk factor for CVD in the general population, but its role in atherosclerosis in patients with RA is not well defined.

METHODS

We determined the urine albumin to creatinine ratio (UACR) in 136 patients with RA and 79 controls. Individuals with diabetes or a clinical history of CVD were excluded. We measured coronary artery calcium (CAC) with electron beam computer tomography and augmentation index (AIx) using pulse wave analysis. In patients with RA, erythrocyte sedimentation rate and concentrations of vascular cell adhesion protein-1 (VCAM-1), interleukin 10 (IL-10), C-reactive protein, IL-6, tumor necrosis factor-α, and cystatin-C were measured and results correlated with UACR.

RESULTS

Patients with RA had higher UACR [median (interquartile range): 7.6 (4.0-15.5) mg/g] than control subjects: 5.6 (3.3-9.0) mg/g; p = 0.02. The presence of CAC was not associated with UACR in RA or control subjects. In patients with RA, UACR was significantly correlated with AIx (rho = 0.24, p = 0.01), higher levels of VCAM-1 (rho = 0.2, p = 0.01), and lower levels of IL-10 (rho = -0.2, p = 0.02). The association between AIx and higher UACR remained significant in multivariate analysis [β coefficient of 1.5 (95% CI 0.1-2.8), p = 0.03 that adjusted for age, sex, and race].

CONCLUSION

Urinary albumin excretion was higher in patients with RA than controls and correlated with increased arterial stiffness, higher VCAM-1, and lower IL-10 concentrations.

Reversing vascular dysfunction in rheumatoid arthritis: improved augmentation index but not endothelial function with peroxisome proliferator-activated receptor γ agonist therapy

OBJECTIVE

To examine the hypothesis that improving insulin sensitivity improves vascular function in rheumatoid arthritis (RA).

METHODS

We performed a 20-week, single center, randomized, double-blind, placebo-controlled crossover study. Patients with RA (n = 34) with moderate disease activity who were receiving stable disease-modifying antirheumatic drug therapy were randomized to drug sequence, receiving either pioglitazone 45 mg/day or matching placebo for 8 weeks, followed by a 4-week washout period and the alternative treatment for 8 weeks. We measured changes in vascular stiffness (augmentation index and aortic pulse wave velocity [PWV]), endothelial function (reactive hyperemia index), and blood pressure. High-sensitivity C-reactive protein levels and the homeostatic model assessment of insulin resistance were also measured. The treatment effect of pioglitazone on outcomes was analyzed using linear mixed-effects models.

RESULTS

Pioglitazone treatment resulted in a change in augmentation index of -4.7% units (95% confidence interval [95% CI] -7.9, -1.5) (P = 0.004) and in diastolic blood pressure of -3.0 mm Hg (95% CI -5.7, -0.2) (P = 0.03), but did not significantly change aortic PWV (P = 0.33) or reactive hyperemia index (P = 0.46). The improvements in augmentation index and diastolic blood pressure were not mediated by the effect of pioglitazone on insulin resistance or inflammation.

CONCLUSION

Our findings indicate that pioglitazone improves some indices of vascular function, including augmentation index and diastolic blood pressure, in patients with RA. This is not mediated by improved insulin sensitivity.

Peroxisome proliferator-activated receptor γ agonist effect on rheumatoid arthritis: a randomized controlled trial

Introduction

Rheumatoid arthritis (RA), a chronic inflammatory disease, is associated with insulin resistance. Experimental evidence indicates that the relationship between insulin resistance and inflammation is bidirectional: Inflammation promotes insulin resistance, and insulin resistance promotes inflammation. Therefore, we examined the hypothesis that pioglitazone, a thiazolidinedione peroxisome proliferator-activated receptor γ agonist, would decrease inflammation and disease activity and improve insulin resistance in patients with RA.

Methods

In a single-center, randomized, double-blind, placebo-controlled crossover study patients with RA (N = 34) receiving stable therapy were randomized to also receive either pioglitazone 45 mg daily (n = 17) or matching placebo (n = 17) for eight weeks. This was followed by a four-week washout period and alternative treatment for eight weeks. Outcomes included change in Disease Activity Score in 28 joints (DAS28) score, individual components of the DAS28 score and homeostatic model assessment for insulin resistance (HOMA). Intention-to-treat analysis and linear mixed-effects models were used.

Results

Patients had a mean (±SD) age of 51 (±14.2) years, 82.4% were female and baseline DAS28 high-sensitivity C-reactive protein (DAS28-CRP) was 4.58 (±1.1) units. Addition of pioglitazone was associated with a 9.3% reduction (95% confidence interval (CI) = 0.17% to 17.6%) in DAS28-CRP (P = 0.046), but no significant change in DAS28 erythrocyte sedimentation rate (DAS28-ESR) (P = 0.92). There was a 10.7mm (95% CI = 0.4 to 20.9 mm) improvement in patient-reported global health (P = 0.042), a 48.6% decrease (95% CI = 27.6% to 63.5%) in CRP (P < 0.001) and a 26.4% decrease (95% CI = 3.7% to 43.8%) in insulin resistance as measured by HOMA (P = 0.025), but no significant reduction in swollen or tender joint count or in ESR (all P > 0.05). Lower-extremity edema was more common during pioglitazone treatment (16%) than placebo (0%).

Conclusion

Addition of pioglitazone to RA therapy improves insulin resistance and modestly reduces RA disease activity measured by DAS28-CRP and two of its components, including patient-reported global health and CRP, but not DAS28-ESR or ESR.

Trial registration

NCT00763139

Association of epicardial adipose tissue with cardiometabolic risk and metabolic syndrome in patients with rheumatoid arthritis

OBJECTIVE

Patients with rheumatoid arthritis (RA) have increased coronary atherosclerosis possibly related to increased prevalence of visceral adiposity, insulin resistance, and metabolic syndrome. Epicardial adipose tissue (EAT), a type of visceral fat, may contribute to cardiometabolic risk. The aim of this study was to measure EAT volume in patients with RA and determine its relationship with cardiometabolic risk markers and coronary artery calcium.

METHODS

EAT volume and coronary artery calcium score were measured by noncontrast cardiac computed tomography and compared in RA patients (n = 162) and controls (n = 89). The relationships between EAT volume and markers of cardiometabolic risk in RA were examined with adjustment for age, race, and sex.

RESULTS

Among RA patients, EAT volume was positively associated with interleukin-6 (P = 0.03), triglycerides (P = 0.004), hypertension (P = 0.01), homeostatic model of insulin resistance (HOMA) (P < 0.001), smoking history (P = 0.04), and homocysteine level (P = 0.001), and negatively associated with high-density lipoprotein (P = 0.005). With further adjustment for waist circumference (a measure of visceral obesity), EAT volume remained independently associated with triglycerides, HOMA, current smoking, and homocysteine level (all P < 0.05). EAT volume was not associated with corticosteroid use or coronary artery calcium score. Patients with metabolic syndrome had significantly greater EAT volume (P < 0.001) and each increase in metabolic syndrome criteria was associated, on average, with a 20% increase (95% confidence interval 14-26%) in EAT volume (P < 0.001).

CONCLUSION

EAT volume is associated with metabolic syndrome and cardiometabolic risk factors, including insulin resistance, triglycerides, current smoking, and homocysteine levels, but not with coronary artery calcium in RA patients.

Free fatty acids are associated with metabolic syndrome and insulin resistance but not inflammation in systemic lupus erythematosus

Free fatty acids (FFAs) are implicated in the pathogenesis of insulin resistance and atherosclerosis. Inflammatory cytokines promote lipolysis and increase FFAs, a cause of endothelial dysfunction and increased atherosclerosis risk. We hypothesized that increased inflammation is associated with increased FFAs, resulting in insulin resistance and atherosclerosis in patients with systemic lupus erythematosus (SLE). We measured clinical variables, serum FFAs, homeostasis model assessment for insulin resistance (HOMA), inflammatory cytokines, markers of endothelial activation, cholesterol concentrations and coronary artery calcium in 156 patients with SLE and 90 controls. We compared FFAs in patients with SLE and controls using Wilcoxon rank sum tests and further tested for the independent association between FFAs and disease status with adjustment for age, race and sex using multivariable regression models. We assessed the relationship between FFAs and continuous variables of interest using Spearman correlation and multivariable regression analysis. Levels of FFAs were higher in patients with SLE than controls (0.55 mmol/l (0.37-0.71) vs 0.44 mmol/l (0.32-0.60), P = 0.02). Levels of FFAs remained significantly higher among patients with SLE after adjustment for age, race and sex (P = 0.03) but not after further adjustment for body mass index (P = 0.13). FFA levels did not differ according to the usage of current immunosuppressive medications in univariate and adjusted analysis (all P > 0.05). Among patients with SLE, concentrations of FFAs were higher among those with metabolic syndrome compared to those without (0.66 mmol/l (0.46-0.81) vs 0.52 mmol/l (0.35-0.66), P < 0.001). FFAs were positively correlated with insulin resistance (HOMA) (rho = 0.23, P = 0.004, P adjusted = 0.006) and triglyceride levels (rho = 0.22, P = 0.01, P adjusted = 0.004). FFAs were not associated with inflammatory cytokines (IL-6, TNF-α) (all P > 0.05) but were positively associated with levels of E-selectin (rho = 0.33, P = < 0.001, P adjusted = 0.001) and ICAM-1 (rho = 0.35, P < 0.001, P adjusted = 0.001). FFAs were correlated with coronary artery calcium score (rho = 0.20, P = 0.01) but this was attenuated after adjustment for age, race and sex (P = 0.33). From our study we concluded that FFAs are elevated in patients with SLE, particularly those with metabolic syndrome. FFAs in patients with SLE are not associated with markers of generalized inflammation but are associated with insulin resistance and markers of endothelial activation.

Free fatty acids are associated with insulin resistance but not coronary artery atherosclerosis in rheumatoid arthritis

BACKGROUND

Free fatty acids (FFAs) affect insulin signaling and are implicated in the pathogenesis of insulin resistance and atherosclerosis. Inflammatory cytokines such as interleukin-6 (IL-6) increase lipolysis and thus levels of FFAs. We hypothesized that increased IL-6 concentrations are associated with increased FFAs resulting in insulin resistance and atherosclerosis in rheumatoid arthritis (RA).

METHODS

Clinical variables, serum FFAs and inflammatory cytokines, homeostasis model assessment for insulin resistance (HOMA-IR), and coronary artery calcium were measured in 166 patients with RA and 92 controls. We compared serum FFAs in RA and controls using Wilcoxon rank sum tests and further tested for multivariable association by adjusting for age, race, sex and BMI. Among patients with RA, we assessed the relationship between serum FFAs and inflammatory cytokines, HOMA-IR, and coronary artery calcium scores using Spearman correlation and multivariable regression analyses.

RESULTS

Serum FFAs did not differ significantly in patients with RA and controls (0.56mmol/L [0.38-0.75] and 0.56mmol/L [0.45-0.70] respectively, p=0.75). Presence of metabolic syndrome was associated with significantly increased serum FFAs in both RA and controls (p=0.035 and p=0.025). In multivariable regression analysis that adjusted for age, race, sex and BMI, serum FFAs were associated with HOMA-IR (p=0.011), CRP (p=0.01), triglycerides (p=0.005) and Framingham risk score (p=0.048) in RA, but not with IL-6 (p=0.48) or coronary artery calcium score (p=0.62).

CONCLUSIONS

Serum FFAs do not differ significantly in patients with RA and controls. FFAs may contribute to insulin resistance, but are not associated with IL-6 and coronary atherosclerosis in RA.

Duloxetine in the management of diabetic peripheral neuropathic pain

Diabetic neuropathy affects up to 70% of diabetics, and diabetic peripheral neuropathic pain (DPNP) is the most common and debilitating of the diabetic neuropathies. DPNP significantly reduces quality of life and increases management costs in affected patients. Despite the impact of DPNP, management is poor with one-quarter of patients receiving no treatment and many treated with medications having little or no efficacy in managing DPNP. Duloxetine is one of two drugs approved by the United States Food and Drug Administration for DPNP management. Duloxetine is a serotonin and norepinephrine reuptake inhibitor (SNRI) proven safe, effective, and cost-saving in reducing DPNP symptoms at a dose of 60 mg/day. Duloxetine doses greater than 60 mg/day for DPNP management are not recommended since they are no more efficacious and associated with more side effects; addition of pregabalin or gabapentin for these patients may be beneficial. Side effects of duloxetine are generally mild and typical for the SNRI class including nausea, dizziness, somnolence, fatigue, sweating, dry mouth, constipation, and diarrhea. Given its other indications, duloxetine is a particularly good choice for DPNP treatment in patients with coexisting depression, anxiety, fibromyalgia, or chronic musculoskeletal pain. Duloxetine treatment had no clinically significant effect on glycemic control and did not increase the risk of cardiovascular events in diabetes patients. However, duloxetine use should be avoided in patients with hepatic disease or severe renal impairment. Given its safety, efficacy, and tolerability, duloxetine is an excellent choice for DPNP treatment in many patients.

Milnacipran for the management of fibromyalgia syndrome

Fibromyalgia syndrome (FMS) is a widespread pain condition associated with fatigue, cognitive dysfunction, sleep disturbance, depression, anxiety, and stiffness. Milnacipran is one of three medications currently approved by the Food and Drug Administration in the United States for the management of adult FMS patients. This review is the second in a three-part series reviewing each of the approved FMS drugs and serves as a primer on the use of milnacipran in FMS treatment including information on pharmacology, pharmacokinetics, safety and tolerability. Milnacipran is a mixed serotonin and norepinephrine reuptake inhibitor thought to improve FMS symptoms by increasing neurotransmitter levels in descending central nervous system inhibitory pathways. Milnacipran has proven efficacy in managing global FMS symptoms and pain as well as improving symptoms of fatigue and cognitive dysfunction without affecting sleep. Due to its antidepressant activity, milnacipran can also be beneficial to FMS patients with coexisting depression. However, side effects can limit milnacipran tolerability in FMS patients due to its association with headache, nausea, tachycardia, hyper- and hypotension, and increased risk for bleeding and suicidality in at-risk patients. Tolerability can be maximized by starting at low dose and slowly up-titrating if needed. As with all medications used in FMS management, milnacipran works best when used as part of an individualized treatment regimen that includes resistance and aerobic exercise, patient education and behavioral therapies.