Biomarkers For Rheumatoid Arthritis Research Articles

Filgotinib, a JAK1 Inhibitor, Modulates Disease-Related Biomarkers in Rheumatoid Arthritis: Results from Two Randomized, Controlled Phase 2b Trials.

IntroductionThe Janus kinase (JAK) inhibitor therapeutic class has shown significant clinical benefit in the treatment of rheumatoid arthritis (RA). We sought to gain insight into the mode of action and immunological effects of filgotinib, a JAK1 selective inhibitor, in active RA by analyzing secreted and cell-based biomarkers key to RA pathophysiology in two phase 2b trials of filgotinib in active RA.MethodsImmune cell subsets and 34 serum biomarkers were analyzed longitudinally over 12 weeks using blood samples collected from patients with active RA receiving filgotinib (100 or 200 mg once daily) or placebo (PBO) in the two phase 2b trials (DARWIN 1, on a background of methotrexate, and DARWIN 2, as monotherapy).ResultsConsistently across both studies, filgotinib treatment decreased multiple immune response biomarkers that have key roles in RA for immune response, and decreased markers that promote matrix degradation, angiogenesis, leukocyte adhesion, and recruitment. Filgotinib did not significantly modulate T and natural killer (NK) lymphoid subsets, but slightly increased B cell numbers after 12 weeks. Multiple correlations were observed for changes in biomarkers with disease activity score 28-CRP. MIP1β showed modest predictivity at baseline for ACR50 response at 12 weeks in the 100 mg filgotinib dose across both studies (AUROC, 0.65 and 0.67, p < 0.05).ConclusionsFilgotinib regulates biomarkers from multiple pathways, indicative of direct and indirect network effects on the immune system and the stromal response. These effects were not associated with reductions of major circulating lymphoid populations.Trial RegistrationClinicalTrials.gov, NCT01888874, NCT01894516.Electronic supplementary materialThe online version of this article (10.1007/s40744-019-00192-5) contains supplementary material, which is available to authorized users.

Coverage degrees of colloids on electrochemical electrodes and signal amplification for anti-citrullinated peptide antibody detection

Gold nanoparticles (AuNPs) have been used to increase the power of electrochemical biosensors. However, densities and pattern distributions of AuNPs colloids have not been determined yet. In this report, we attempt identifying coverable densities of AuNPs on interdigitated electrodes (IDEs) and increasing the sensing signal by using cyclic antigen (CCP)-coated-AuNPs in impedance biosensors. IDEs were covalently functionalized with CCP-coated AuNPs and used for detection of anti-CCP antibody (ACPA), a remarkable biomarker for rheumatoid arthritis. 36% and 82% of ACPA in human commercial serum were captured by a low CCP (300 CCP per 40-nm nanoparticles) and high CCP (17 × 105 CCP per 40-nm nanoparticles) densities of colloids, respectively. Coverage of the colloids on gaps between two digits of IDEs were observed about at 2.7 × 106 AuNPs (30 nm) per 1 μm2 for low signal-to-noise ratio (SNR). The enzyme-catalyzed deposition of silver nanocrystal increased the SNR of the impedance signal up to 7.8 folds of magnitude higher than un-deposited counterparts. Sensitivity and limit of detection were determined at 1.3 ng/mL and 0.12 ng/mL, respectively, at a frequency 900 kHz in the range of 200–2000 kHz. Finally, Principal Component Analysis (PCA) showed the ability of the biosensor to follow variation over time of the number of CCP and therefore also the quantify of ACPA in the samples.

Biomarkers for rheumatoid arthritis associated lung disease

Biomarkers for rheumatoid arthritis associated lung disease

PKM2: A Potential Regulator of Rheumatoid Arthritis via Glycolytic and Non-Glycolytic Pathways.

Immunometabolism provides a new perspective on the pathogenesis of rheumatoid arthritis (RA). In recent years, there have been investigations focusing on the role of intracellular glucose metabolism in the pathogenesis of RA. Previous studies have shown that glycolysis of synovial tissue is increased in RA patients, while glycolysis inhibitors can significantly inhibit synovitis. Pyruvate kinase (PK) is a key enzyme in glycolysis, catalyzing the final rate-limiting step in the process. An isoform of PK, PKM2, provides favorable conditions for the survival of tumor cells via its glycolytic or non-glycolytic functions and has become a potential therapeutic target in tumors. RA synovium has the characteristic of tumor-like growth, and, moreover, increased expression of PKM2 was identified in the synovial tissue of RA patients in recent studies, indicating the underlying role of PKM2 in RA. PKM2 has potential value as a new therapeutic target or biomarker for RA, but its exact role in RA remains unclear. In this review, the properties of PKM2 and existing research concerning PKM2 and RA are thoroughly reviewed and summarized, and the possible role and mechanism of PKM2 in RA are discussed.

LncRNA PICSAR promotes cell proliferation, migration and invasion of fibroblast-like synoviocytes by sponging miRNA-4701-5p in rheumatoid arthritis.

BackgroundLong non-coding RNAs (lncRNAs) have drawn increasing attention because they play a pivotal role in various types of autoimmune diseases, including rheumatoid arthritis (RA). Fibroblast-like synoviocytes (FLSs), a prominent component of hyperplastic synovial pannus tissue, are the primary effector cells in RA synovial hyperplasia and invasion which can lead to joint destruction. In this study, we investigated whether lncRNAs could act as competing endogenous RNAs to regulate the pathological behaviors of RA-FLSs.MethodsLncRNA microarray was conducted to establish lncRNA expression profiles in FLSs isolated from RA patients and healthy controls (HCs). Differentially expressed lncRNAs were verified by quantitative real-time PCR (qRT-PCR) on RA-FLSs and synovial fluid. The functional role of lncRNA PICSAR downregulation was evaluated in RA-FLSs. We conducted molecular biological analysis to predict miRNAs which have a potential binding site for PICSAR and further refined the results by qRT-PCR. Luciferase reporter assay was adopted to validate the interaction of lncRNA PICSAR and miR-4701-5p. Western Blot and qPCR were used to identify the target gene and protein. The functional role of miR-4701-5p upregulation was examined in RA-FLSs.FindingsWe identified a long intergenic non-protein-coding RNA162 (LINC00162), also known as lncRNA PICSAR (p38 inhibited cutaneous squamous cell carcinoma associated lincRNA), has significantly higher expression in RA-FLSs and RA synovial fluid. The cell proliferation, migration, invasion and proinflammatory cytokines production of RA-FLSs showed significant alterations after the lncRNA PICSAR suppression. Mechanistically, lncRNA PICSAR functioned through sponging miR-4701-5p in RA-FLSs.InterpretationOur results reveal PICSAR may exert an essential role in promoting synovial invasion and joint destruction by sponging miR-4701-5p in RA and that lncRNA PICSAR may act as a biomarker of RA.

Relationship between polycyclic aromatic hydrocarbons and rheumatoid arthritis in US general population, NHANES 2003–2012

The purpose of this study was to explore the association between urinary concentrations of polycyclic aromatic hydrocarbon (PAH) metabolites and the prevalence of rheumatoid arthritis (RA). Cross-sectional data were analyzed from the National Health and Nutrition Examination Survey (NHANES) 2003–2012 using levels of nine monohydroxylated urinary PAH metabolites as exposure. Multivariable logistic regression was used to examine the association between urinary biomarkers of PAHs and RA. All of the models were adjusted for age, sex, race, education level, marital status, smoking, BMI, physical activity, energy, diabetes, and survey cycle. Ultimately, 6,072 adults (3,108 men and 2,964 women) 20 years of age or older were analyzed. In the quartile analyses, compared with the lowest quartile, increased RA prevalence was observed in the participants with the highest quartile of 2-hydroxynapthalene (OR = 1.89, 95% CI = 1.28–2.78), 3-hydroxyfluorene (OR = 1.55, 95% CI = 1.07–2.25), 2-hydroxyfluorene (OR = 1.51, 95% CI = 1.02–2.24), 3-hydroxyphenanthrene (OR = 1.50, 95% CI = 1.09–2.07), and 9-hydroxyfluorene (OR = 1.60, 95% CI = 1.10–2.33) in a fully adjusted model, respectively. In the subgroup analysis of current smokers, compared with the participants with lower urinary PAH scores, those with higher scores had a dramatically increased prevalence of RA (OR = 15.46, 95% CI = 3.11–76.75) in the adjusted model. There was a significant interaction between all of the urinary PAH metabolite levels and smoking status in the relationship with RA (P < 0.05). High levels of urinary PAH metabolites are positively associated with RA prevalence in the US general population. PAH exposure and smoking may potentially interact to increase the prevalence of RA. Further prospective studies are needed to clarify the possible effect of PAHs on RA.

Dissecting the Role of NF-κb Protein Family and Its Regulators in Rheumatoid Arthritis Using Weighted Gene Co-Expression Network.

Rheumatoid arthritis (RA) is a chronic synovial autoinflammatory disease that destructs the cartilage and bone, leading to disability. The functional regulation of major immunity-related pathways like nuclear factor kappa B (NF-κB), which is involved in the chronic inflammatory reactions underlying the development of RA, remains to be explored. Therefore, this study has adopted statistical and knowledge-based systemic investigations (like gene correlation, semantic similarity, and topological parameters based on graph theory) to study the gene expression status of NF-κB protein family (NKPF) and its regulators in synovial tissues to trace the molecular pathways through which these regulators contribute to RA. A complex protein–protein interaction map (PPIM) of 2,742 genes and 37,032 interactions was constructed from differentially expressed genes (p ≤ 0.05). PPIM was further decomposed into a Regulator Allied Protein Interaction Network (RAPIN) based on the interaction between genes (5 NKPF, 31 seeds, 131 hubs, and 652 bottlenecks). Pathway network analysis has shown the RA-specific disturbances in the functional connectivity between seed genes (RIPK1, ATG7, TLR4, TNFRSF1A, KPNA1, CFLAR, SNW1, FOSB, PARVA, CX3CL1, and TRPC6) and NKPF members (RELA, RELB, NFKB2, and REL). Interestingly, these genes are known for their involvement in inflammation and immune system (signaling by interleukins, cytokine signaling in immune system, NOD-like receptor signaling, MAPK signaling, Toll-like receptor signaling, and TNF signaling) pathways connected to RA. This study, for the first time, reports that SNW1, along with other NK regulatory genes, plays an important role in RA pathogenesis and might act as potential biomarker for RA. Additionally, these genes might play important roles in RA pathogenesis, as well as facilitate the development of effective targeted therapies. Our integrative data analysis and network-based methods could accelerate the identification of novel drug targets for RA from high-throughput genomic data.

Epigenetically regulated co-expression network of genes significant for rheumatoid arthritis.

Aim: To identify epigenetically regulated network of genes in peripheral blood mononuclear cells significant for rheumatoid arthritis (RA). Methods: Differentially expressed genes (DEGs) and their associated differentially expressed miRNAs and differentially methylated positions (DMPs) were identified. Causal inference test (CIT)identified the causal regulation chains. The analyses, for example, weighted gene co-expression network (WGCNA), protein-protein interaction and functional enrichment, evaluated interaction patterns among the DEGs and the associated epigenetic factors. Results: A total of 181 DEGs were identified. The DEGs were significantly regulated by DMPs and/or differentially expressed miRNAs. Causal inference test analyses identified 18 causal chains of DMP-DEG-RA and 16 intermediate DEGs enriched in 'protein kinase inhibitor activity'. BTN2A1 was co-expressed with other 9 intermediate genes and 11 known RA-associated genes and played a pivotal role in the co-expression network. Conclusion: Epigenetically regulated network of genes in peripheral blood mononuclear cells (PBMC)contributed to RA. The causal DMPs and key intermediate genes may serve as potential biomarkers for RA.

Pre-analytical and analytical confounders of serum calprotectin as a biomarker in rheumatoid arthritis.

Background There is a need for additional biomarkers to assist in the diagnosis and prognosis of rheumatoid arthritis (RA). The aim of our study was to evaluate the (pre-analytical, analytical and clinical) performance of serum calprotectin as a marker of inflammation in RA. Methods The study population included 463 rheumatologic patients (including 111 RA patients and 352 controls) who for the first time consulted a rheumatologist, 20 healthy controls and 27 patients with an infectious disease. Calprotectin was measured (using four different assays) in serum or in serum and EDTA plasma (healthy controls and infectious disease group). For rheumatologic patients, results for C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA) were available. Results Results for blood calprotectin were assay- and matrix-dependent, with higher values found in serum than in plasma. Serum calprotectin was higher in RA patients than in rheumatologic diseased controls and in healthy controls. Serum calprotectin was lower in RA patients than in patients with an infectious disease. Serum calprotectin was associated with disease activity (DAS score). The area under the curve (AUC) to discriminate RA from controls was 0.756 for CRP, 0.714 for ESR and 0.726-0.783 for calprotectin. Conclusions Our data document that calprotectin measurement is assay- and matrix-dependent. Serum calprotectin is associated with disease activity. Additional (prospective) studies are warranted to further evaluate the prognostic and diagnostic value of blood calprotectin measurements.

METTL3 Attenuates LPS-Induced Inflammatory Response in Macrophages via NF-κB Signaling Pathway.

Methyltransferase-like 3 (METTL3), an RNA N6-methyladenosine (m6A) methyltransferase, is essential for the m6A mRNA modification. As a key enzyme of m6A methylation modification, METTL3 has been implicated in immune and inflammation regulation. However, little is known of the role and underlying mechanism of METTL3 in rheumatoid arthritis (RA). The aim of the present study is to elucidate the function and potential mechanism of METTL3 in RA pathogenesis. We used quantitative real-time polymerase chain reaction to detect the expression of METTL3 in RA patients and controls as well as the macrophage cell line. CCK-8 was used for cell proliferation assay. Enzyme-linked immunosorbent assay (ELISA) was adopted to estimate the generation of IL-6 and TNF-α in macrophages. Western blot and immunofluorescence were applied to evaluate the activation of NF-κB in macrophages. The expression of METTL3 was significantly elevated in patients with RA. It was positively associated with CRP and ESR, two common markers for RA disease activity. Besides, LPS could enhance the expression and biological activity of METTL3 in macrophages, while overexpression of METTL3 significantly attenuated the inflammatory response induced by LPS in macrophages. Moreover, the effect of METTL3 on LPS-induced inflammation in macrophages was dependent on NF-κB. This study firstly demonstrates the critical role of METTL3 in RA, which provides novel insights into recognizing the pathogenesis of RA and a promising biomarker for RA.

An Overview of VPAC Receptors in Rheumatoid Arthritis: Biological Role and Clinical Significance.

The axis comprised by the Vasoactive Intestinal Peptide (VIP) and its G protein-coupled receptors (GPCRs), VPAC1, and VPAC2, belong to the B1 family and signal through Gs or Gq proteins. VPAC receptors seem to preferentially interact with Gs in inflammatory cells, rather than Gq, thereby stimulating adenylate cyclase activity. cAMP is able to trigger various downstream pathways, mainly the canonical PKA pathway and the non-canonical cAMP-activated guanine nucleotide exchange factor (EPAC) pathway. Classically, the presence of VPACs has been confined to the plasma membrane; however, VPAC1 location has been described in the nuclear membrane in several cell types such as activated Th cells, where they are also functional. VPAC receptor signaling modulates a number of biological processes by tipping the balance of inflammatory mediators in macrophages and other innate immune cells, modifying the expression of TLRs, and inhibiting MMPs and the expression of adhesion molecules. Receptor signaling also downregulates coagulation factors and acute-phase proteins, promotes Th2 over Th1, stimulates Treg abundance, and finally inhibits a pathogenic Th17 profile. Thus, the VIP axis signaling regulates both the innate and adaptive immune responses in several inflammatory/autoimmune diseases. Rheumatoid arthritis (RA) is a complex autoimmune disease that develops on a substrate of genetically susceptible individuals and under the influence of environmental factors, as well as epigenetic mechanisms. It is a heterogeneous disease with different pathogenic mechanisms and variable clinical forms between patients with the same diagnosis. The knowledge of VIP signaling generated in both animal models and human ex vivo studies can potentially be translated to clinical reality. Most recently, the beneficial effects of nanoparticles of VIP self-associated with sterically stabilized micelles have been reported in a murine model of RA. Another novel research area is beginning to define the receptors as biomarkers in RA, with their expression levels shown to be associated with the activity of the disease and patients-reported impairment. Therefore, VPAC expression together VIP genetic variants could allow patients to be stratified at the beginning of the disease with the purpose of guiding personalized treatment decisions.

Features of the subpopulation composition of dendritic cells in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most common rheumatic diseases. Dendritic cells (DCs) as the main antigen-presenting cells play an important role in the pathogenesis of RA. There are two major DC populations: myeloid and plasmacytoid DCs (mDCs and pDCs). B cells as antibody-producing cells also play an important role in the pathogenesis of RA. The probability of achieving low disease activity and clinical and laboratory remission has been proven to be maximal in the very early period of the disease and in the patients who have not been previously prescribed disease-modifying antirheumatic drugs (DMARDs). In this connection, it is necessary to elaborate additional criteria and biomarkers for early RA. Objective : to investigate the subpopulation composition of DCs in patients with early-stage RA. Patients and methods . The investigation enrolled 60patients with RA who met the 2010 ACR/EULAR and the 1987ACR criteria. The patients with RA were divided into two groups: 1) 30patients with early RA (the disease duration was not more than 1 year); 2) 30 patients with advanced RA. A control group consisted of 30 patients with osteoarthritis (OA) who met the ACR criteria. All the patients with RA were treated with DMARDs. The patients with early RA had not previously received DMARDs; after being included in the study, they were prescribed methotrexate 15-20 mg/week. The patients with advanced RA took methotrexate 15-25 mg/week (n=24), sulfasalazine 2 g/day (n=5), or leflunomide 20 mg/day (n=1). At the first stage, the levels of different subpopulations of DCs and B lymphocytes were studied in the patients with early RA before initiation of therapy and in those with advanced RA and in the control persons. At the following stage, the time course of changes was investigated in the subpopulation composition of DCs and B lymphocytes during therapy. Results and discussion . The subpopulations of peripheral blood DCs in early RA were characterized. A subpopulation of mDCs was shown to dominate in the patients with early RA versus those with advanced RA or osteoarthritis (OA). In addition, the patients with RA showed a high B lymphocyte level. It was noted that there was no significant differences in the level of pDCs between RA and OA patients and there was an inverse relationship between the relative peripheral blood level of pDC and disease activity, which confirms the immunosuppressive role of pDCs in the pathogenesis of RA. The levels of mDCs and B lymphocytes during DMARD therapy were ascertained to significantly decrease to those seen in healthy donors. Conclusion . Thus, the findings suggest that the number of mDCs and B lymphocytes increases in patients with early RA, unlike those with OA. In addition, the change in the number of mDCs and B cells during therapy is associated with the dynamics of disease activity and may suppose that mDCs are a target for the action of DMARDs.

New progress in research and application of biomarkers for rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic chronic inflammatory disease of unclear pathogenesis that is manifested by a progressive and destructive poly-arthritis. The early diagnosis of RA is critical to determine the severity of the disease, which may have an impact on improving the prognosis and life quality of patients with RA. A variety of autoantibodies and protein biomarkers have been reported in the serum of RA patients. Herein will be reviewed updates in the field of serum autoantibodies and biomarkers of RA, as well as their application in diagnosis, prognosis, and potential future directions for study. Key words: Arthritis,rheumatoid; Autoantibodies; Biomarkers

N-Linked Glycans in the Variable Domain of IgG Anti-Citrullinated Protein Antibodies Predict the Development of Rheumatoid Arthritis.

ObjectiveAnti–citrullinated protein antibodies (ACPAs) are disease‐specific biomarkers in rheumatoid arthritis (RA). More than 90% of IgG ACPAs harbor N‐linked glycans in the antibody variable (V) domain. The corresponding N‐glycosylation sites in ACPA V‐region sequences result from somatic hypermutation, a T cell–dependent process. As ample evidence indicates that T cells drive the maturation of the ACPA response prior to arthritis onset, we undertook this study to investigate whether the presence of glycans in IgG ACPA V domains predicts the transition from predisease autoimmunity to overt RA.MethodsWe analyzed 2 independent sets of serum samples obtained from 126 ACPA‐positive first‐degree relatives (FDRs) of RA patients. Both sets originated from an Indigenous North American population and comprised cross‐sectional and longitudinal samples of individuals who did or did not develop inflammatory arthritis. Serum IgG ACPAs were affinity‐purified and subjected to ultra high‐performance liquid chromatography–based glycan analysis.ResultsIn both data sets, FDR‐derived IgG ACPA displayed markedly lower levels of V domain glycans (<50%) compared to IgG ACPA from RA patients. Notably, FDRs who later developed RA showed extensive V‐domain glycosylation before the onset of arthritis. Moreover, IgG ACPA V‐domain glycosylation was strongly associated with future development of RA (hazard ratio 6.07 [95% confidence interval 1.46–25.2]; P = 0.013).ConclusionExtensive glycosylation of the IgG ACPA V domain is present in a subset of predisposed FDRs of Indigenous North American RA patients. The presence of this feature substantially increases the risk of RA development. Based on these findings, we propose that glycosylation of the IgG ACPA V domain represents a predictive marker for RA development in ACPA‐positive individuals and may serve to better target prevention measures.

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

The Outcome Measures in Rheumatology Soluble Biomarker Working Group initiated an international, multicenter, prospective study, the Rheumatoid Arthritis (RA) BIODAM cohort, to generate resources for the clinical validation of candidate biomarkers predictive of radiographic progression. This first report describes the cohort, clinical outcomes, and radiographic findings. Patients with RA from 38 sites in 10 countries starting or changing conventional synthetic disease-modifying antirheumatic drugs and/or starting tumor necrosis factor inhibitors were followed for 2 years. Participating physicians were required to adhere to a treat-to-target strategy. Biosamples (serum, urine) were acquired every 3 months, radiography of hands and feet every 6 months, and ultrasound of hands and feet every 3 months in a subset. Primary endpoint was radiographic progression by the Sharp/van der Heijde score. A total of 571 patients were recruited and 439 (76.9%) completed 2-year followup. At baseline, the majority was female (76%), mean age 55.7 years, and mean disease duration 6.5 years. Patients had a mean of 8.4 swollen and 13.6 tender joints, 44-joint count Disease Activity Score (DAS44) 3.8, 77.7% rheumatoid factor-positive or anticitrullinated protein antibody-positive. Percentage of patients in DAS and American College of Rheumatology remission at 2 years was 52.2% and 27.1%, respectively. Percentage of patients with radiographic progression (> 0.5) at 1 and 2 years was 38.2% and 59.9%, respectively. The RA BIODAM prospective study succeeded in generating an extensive list of clinical, imaging (2343 radiographs), and biosample (4638 sera) resources that will be made available to expedite the identification and validation of biomarkers for radiographic damage endpoints. (Clinicaltrials.gov: NCT01476956, clinicaltrials.gov/ct2/show/NCT01476956).

How to investigate: Pre-clinical rheumatoid arthritis.

Multiple studies have shown that there is a pre-clinical period preceding the development of rheumatoid arthritis (RA). During this period, complex interactions between the environmental and genetic causes occur, and the expression "preclinical RA" has been proposed to define it. Early treatment intervention is associated with less joint damage and has an increased possibility of achieving remission. In this review, we provide an overview of the preclinical phases of RA, new immunological and imaging biomarkers, and the clinical features, and the management of individuals at-risk of developing RA.

A Pilot Study to Evaluate the Effects of Oral N-Acetyl Cysteine on Inflammatory and Oxidative Stress Biomarkers in Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is a common inflammatory disease of the joints. Due to the importance of inflammation and oxidative stress in the pathogenesis of RA, drugs that have anti-oxidant and anti-inflammatory properties, such as N-acetyl Cysteine (NAC), can be used as adjunctive therapy in patients with RA. The aim of this study was to evaluate the effects of oral NAC on inflammatory cytokines and oxidative stress in patients with RA. Adjunct to standard treatment, the NAC group (23 patients) received 600 mg of NAC twice daily and the placebo group (19 patients) received identical placebo twice daily for 12 weeks. Serum levels of Total Oxidant Status (TOS), Total Antioxidant Capacity (TAC), nitric oxide (NO), Total Thiol Groups (TTG), Malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), interleukin- 6 (IL-6), C-reactive Protein (CRP), and Erythrocyte Sedimentation Rate (ESR) were measured at baseline and at the end of the study. Results showed that in the NAC group, the serum levels of MDA, NO, IL-6, TNF-α, ESR and CRP were significantly lower than the baseline. Also, the serum level of TAC and TTG, as antioxidant parameters, increased significantly. However, only NO, MDA and TTG showed a significant difference in the NAC group as compared to the placebo group at the end of study. According to the results of this study, oral NAC can significantly reduce the several oxidative stress factors and inflammatory cytokines. These results need to be confirmed in larger studies while considering clinical outcomes of RA patients.

The Importance of Antibodies and other Molecules as Biomarkers in Rheumatoid Arthritis

The Importance of Antibodies and other Molecules as Biomarkers in Rheumatoid Arthritis

Galectin-1, -4, and -7 Were Associated with High Activity of Disease in Patients with Rheumatoid Arthritis.

Background Due to the variety of functions that galectins (Gal) possess, it is clear that they participate in the pathogenesis of rheumatoid arthritis (RA). Although some studies demonstrate their functions, there is still no correlation with the clinical data of the disease, having the physiological meaning still unknown. Objectives To compare serum levels of Gal-1, -4, and -7 in patients with RA and healthy controls and to correlate them with clinical parameters. Methods Serum samples were collected from patients with RA and healthy donors to determine the serum levels of Gal-1, -4, and -7. Results Serum levels of Gal-1, -4, and -7 were significantly higher in RA patients compared to controls. We evaluated disease activity (CDAI) with serum levels of galectins and found that patients who were high in disease activity had high levels of galectin compared to the moderate activity group. Galectin-4 had higher levels in patients who were in high activity when compared to the group in remission or low activity. Evaluating the activity of the individual disease (DAS28), patients in high individual activity had high levels of Gal-4 when compared to the group in remission or low activity. We also found an association between positive rheumatoid factor and Gal-1 and Gal-4 levels. Conclusion Our results show for the first time the relationship between serum levels of galectin and the clinical parameters of patients with RA. Demonstrating their role in pathogenesis, new studies with galectins are needed to assess how they function as a biomarker in RA.

Metabolomic approach to the exploration of biomarkers associated with disease activity in rheumatoid arthritis.

We aimed to investigate metabolites associated with the 28-joint disease activity score based on erythrocyte sedimentation rate (DAS28-ESR) in patients with rheumatoid arthritis (RA) using capillary electrophoresis quadrupole time-of-flight mass spectrometry. Plasma and urine samples were collected from 32 patients with active RA (DAS28-ESR≥3.2) and 17 with inactive RA (DAS28-ESR<3.2). We found 15 metabolites in plasma and 20 metabolites in urine which showed a significant but weak positive or negative correlation with DAS28-ESR. When metabolites between active and inactive patients were compared, 9 metabolites in plasma and 15 in urine were found to be significantly different. Consequently, we selected 11 metabolites in plasma and urine as biomarker candidates which significantly correlated positively or negatively with DAS28-ESR, and significantly differed between active and inactive patients. When a multiple logistic regression model was built to discriminate active and inactive cohorts, three variables—histidine and guanidoacetic acid from plasma and hypotaurine from urine—generated a high area under the receiver operating characteristic (ROC) curve value (AUC = 0.8934). Thus, this metabolomics approach appeared to be useful for investigating biomarkers of RA. Combination of plasma and urine analysis may lead to more precise and reliable understanding of the disease condition. We also considered the pathophysiological significance of the found biomarker candidates.