Agata Burska

Cytokines as Biomarkers in Rheumatoid Arthritis

RA is a complex disease that develops as a series of events often referred to as disease continuum. RA would benefit from novel biomarker development for diagnosis where new biomarkers are still needed (even if progresses have been made with the inclusion of ACPA into the ACR/EULAR 2010 diagnostic criteria) and for prognostic notably in at risk of evolution patients with autoantibody-positive arthralgia. Risk biomarkers for rapid evolution or cardiovascular complications are also highly desirable. Monitoring biomarkers would be useful in predicting relapse. Finally, predictive biomarkers for therapy outcome would allow tailoring therapy to the individual. Increasing numbers of cytokines have been involved in RA pathology. Many have the potential as biomarkers in RA especially as their clinical utility is already established in other diseases and could be easily transferable to rheumatology. We will review the current knowledges relation to cytokine used as biomarker in RA. However, given the complexity and heterogeneous nature of RA, it is unlikely that a single cytokine may provide sufficient discrimination; therefore multiple biomarker signatures may represent more realistic approach for the future of personalised medicine in RA.

Autoantibodies to posttranslational modifications in rheumatoid arthritis.

Autoantibodies have been associated with human pathologies for a long time, particularly with autoimmune diseases (AIDs). Rheumatoid factor (RF) is known since the late 1930s to be associated with rheumatoid arthritis (RA). The discovery of anticitrullinated protein antibodies in the last century has changed this and other posttranslational modifications (PTM) relevant to RA have since been described. Such PTM introduce neoepitopes in proteins that can generate novel autoantibody specificities. The recent recognition of these novel specificities in RA provides a unique opportunity to understand human B-cell development in vivo. In this paper, we will review the three of the main classes of PTMs already associated with RA: citrullination, carbamylation, and oxidation. With the advancement of research methodologies it should be expected that other autoantibodies against PTM proteins could be discovered in patients with autoimmune diseases. Many of such autoantibodies may provide significant biomarker potential.

Gene expression analysis in RA: towards personalized medicine

Gene expression has recently been at the forefront of advance in personalized medicine, notably in the field of cancer and transplantation, providing a rational for a similar approach in rheumatoid arthritis (RA). RA is a prototypic inflammatory autoimmune disease with a poorly understood etiopathogenesis. Inflammation is the main feature of RA; however, many biological processes are involved at different stages of the disease. Gene expression signatures offer management tools to meet the current needs for personalization of RA patient’s care. This review analyses currently available information with respect to RA diagnostic, prognostic and prediction of response to therapy with a view to highlight the abundance of data, whose comparison is often inconclusive due to the mixed use of material source, experimental methodologies and analysis tools, reinforcing the need for harmonization if gene expression signatures are to become a useful clinical tool in personalized medicine for RA patients.

Increased serum resistin in elite endurance athletes with high insulin sensitivity

Aims/hypothesisResistin is an adipokine associated with obesity and type 2 diabetes in animal models, but in humans its role remains uncertain. This study was undertaken to test whether serum resistin is related to insulin resistance and markers of low-grade inflammation in elite athletes taken as a model of extreme insulin sensitivity.Subjects materials and methodsIn 23 elite athletes (sprinters, middle-distance and marathon runners) and in 72 sedentary men including lean and obese individuals with NGT, and obese individuals with IGT or new-onset type 2 diabetes, we assessed insulin sensitivity using a whole-body insulin-sensitivity index (WBISI) derived from a 3-h OGTT; energy homeostasis was also assessed by means of indirect calorimetry, along with circulating adipokines and low-grade pro-inflammatory cyto-chemokines.ResultsProfessional athletes had increased WBISIs (p<0.001) and lipid oxidation (p<0.03); they also showed higher serum resistin concentrations (p<0.001), although the pro-inflammatory chemokines were not increased in comparison with the other study groups. Resistin was independently associated only with fasting plasma NEFA. Increased resistin was detected in the middle-distance and marathon runners, but not in the sprinters when compared with the lean, young, sedentary individuals.Conclusions/interpretationSerum resistin concentration is increased in elite athletes, providing evidence against the notion that resistin levels reflect insulin resistance in humans, as seen in animal studies. Increased resistin was observed in aerobic-endurance, but not sustained-power athletes and this feature appeared to be independently associated with parameters of fatty acid metabolism.

An immunological biomarker to predict MTX response in early RA

Objectives The therapeutic goal for patients with rheumatoid arthritis (RA) is clinical remission. This is best achieved by early diagnosis and appropriate therapeutic intervention. RA is associated with dysregulation of T-cell subsets (naïve, regulatory (Treg) and inflammation-related cells (IRC)) early in the disease. Our aim was to test the hypothesis that T-cell subset quantification can predict the achievement of clinical remission with early treatment in RA. Methods T-cell subsets were quantified in 108 drug-naïve, early RA patients commencing methotrexate (MTX) or MTX+antitumor necrosis factor (anti-TNF) and in 105 healthy controls (HC). The primary outcome assessed was remission (DAS28<2.6). A pilot study used frozen cells (38 patients and 35 HCs, see online supplementary material) and was validated with fresh blood (70 patients and 70 HCs). Results Immune dysregulation in early RA was confirmed with an association between age and reduced naïve cells compared with HCs (p=0.006), a lower age-adjusted Treg and higher IRC frequency (p=0.001). Anticitrullinated peptide antibody (ACPA) positivity was associated with lower naïve (p=0.031) and Treg frequencies (p=0.039). In 50 patients treated with MTX, ACPA/age-adjusted analysis demonstrated that higher naïve cell frequency (relative to HC) was associated with remission (OR 5.90 (1.66 to 20.98), p=0.006, sensitivity/specificity 62%/79%, Positive Predictive Value (PPV)/Negative Predictive Value (NPV) 66%/76%). Remission with MTX+anti-TNF (n=20) was not found to be associated with naïve cell frequency, and for patients with reduced naïve cells the remission rate increased from 24% (MTX) to 42% (MTX+anti-TNF). Conclusions Baseline T-cell subset analysis has a value in predicting early RA remission with first therapy with MTX. Immunological analysis could be used in conjunction with clinical/serological features to predict response to MTX and help select the most appropriate therapy at disease presentation.

Effects of Tumour Necrosis Factor Antagonists on Insulin Sensitivity/Resistance in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis.

Objective Beyond the joints, TNFi (tumour necrosis factor inhibitor) therapy may confer systemic benefits in rheumatoid arthritis (RA). Several studies have investigated the role of TNFi on insulin resistance/sensitivity (IR/IS). This question is of general interest given the emerging evidence linking inflammation and insulin resistance. The main aim of this review was to summarise the published data and to determine the effects of TNFi on IR/IS. Methods We searched the PubMed and ISI Web of Knowledge databases for studies which examined the effects of TNFi on IR/IS. The studies were assessed independently by two reviewers according to a pre-specified protocol. The data on Homeostatic Model Assessment for Insulin resistance (HOMA) and Quantitative Insulin Sensitivity Check Index (QUICKI) were pooled and reported as standard difference in means (SDM) with 95% confidence interval (CI) using a random-effects model. Results A total of eight studies with 260 subjects met the selection criteria. The duration of the studies was from 8 weeks to 12 months. There was statistically significant reduction in HOMA index in six out of eight studies and four reported significant increment in QUICKI. The pooled analysis revealed significant reduction in HOMA [SDM-0.148, 95%CI[-0.278 to -0.017], p=0.026] and increment in QUICKI [SDM 0.312, 95%CI[0.019 to 0.606], p=0.037] with TNFi. Conclusion There is emerging evidence to support that TNFi therapy improves IS and reduces IR in RA. Further, well conducted trials are needed to determine if such effects translate to lower incidence of diabetes in RA or other autoimmune conditions on biologic therapy.

Changes in peripheral blood immune cell composition in osteoarthritis

Summary Objectives Immune age-related abnormalities may synergise with osteoarthritis (OA) pathology. We explored whether abnormalities in the blood immune cell composition are present in OA, beyond defects typically associated with ageing. Design Blood was collected from 121 healthy controls (HC) and 114 OA patients. Synovial biopsies were obtained from another 52 OA patients. Flow cytometry was used to establish the frequencies of lineage subsets, naïve, memory and regulatory T and B-cells, cells with an abnormal phenotype related to inflammation (IRC) and memory-like CD8+ T-cells. Multivariate analysis of covariance (MANCOVA) was used to determine whether the relative subset frequencies differed between HC and OA, controlling for age. Results Expected histology and T/B-cell infiltration were observed. Following age adjusted analysis, we confirmed the lack of age association in HC for CD4+, B, NK and NKT cells but a negative trend for CD8+ T-cells. In OA, CD4+ T-cell and B-cell frequency were lower compared to HC while CD8+ T-cell frequencies were higher. CD8+ memory-like cells were more likely to be found in OA (odds ratio = 15). Increased CD8+ IRC frequencies were also present in OA. The relationship between age and CD4+ or CD8+ naïve T-cells in HC were changed in OA while the age relationships with memory cells were lost. The increase in CD4+ Treg with age was also lost in OA. B-cells showed limited evidence of disturbance. Conclusions Immune dysfunction may be present in OA beyond what appears related to ageing; this requires further investigation.

Increased serum insulin-like growth factor-1 levels in women with gestational diabetes.

BACKGROUND Insulin-like growth factor-1 (IGF-1), which has effects similar to insulin, reduces blood glucose level, improves insulin sensitivity and may play an important role in the pathogenesis of gestational diabetes (GDM). OBJECTIVE The aim of the study was to estimate the concentration of IGF-1 in pregnant women with GDM and 3 months after delivery and find relationships between IGF-1 and clinical and biochemical parameters. MATERIALS AND METHODS 67 women between 24th - 28th week of pregnancy were enrolled in the study (46 with GDM and 21 as a control group). All women underwent clinical and biochemical examinations. Concentrations of IGF-1, adiponectin, fasting glucose, insulin, lipids, CRP, fibrinogen were measured during pregnancy, additionally IGF-1 concentration was determined 3 months after delivery. RESULTS IGF-1, glucose, insulin, CRP, fibrinogen, lipids concentrations and HOMA-IR were significantly higher in women with GDM than in the control group (p<0.05). A significant decrease in IGF-1 concentration was observed in both groups after delivery. In the GDM group significant correlations between IGF-1 and BMI (r=0.370, p<0.05), insulin (r=0.469, p<0.01) and HOMA-IR (r=0.439, p<0.01) were observed. Regression analysis with IGF-1 as a dependent parameter showed that only BMI and insulin remained as predictors, explaining 32% of plasma IGF-1 variation. Re-evaluation after delivery revealed impaired glucose tolerance in 9% of the population studied. CONCLUSIONS Increased IGF-1 concentrations in pregnancy complicated with GDM may partly reflect metabolic disturbances, especially insulin resistance and hyperinsulinemia, and may be one of possible compensatory reactions of the organism in response to these disturbances.

T cell subsets: an immunological biomarker to predict progression to clinical arthritis in ACPA-positive individuals

Objectives Anticitrullinated protein antibody (ACPA)+ individuals with non-specific musculoskeletal symptoms are at risk of inflammatory arthritis (IA). This study aims to demonstrate the predictive value of T cell subset quantification for progression towards IA and compare it with previously identified clinical predictors of progression. Methods 103 ACPA+ individuals without clinical synovitis were observed 3-monthly for 12 months and then as clinically indicated. The end point was the development of IA. Naïve, regulatory T cells (Treg) and inflammation related cells (IRCs) were quantified by flow cytometry. Areas under the ROC curve (AUC) were calculated. Adjusted logistic regressions and Cox proportional hazards models for time to progression to IA were constructed. Results Compared with healthy controls (age adjusted where appropriate), ACPA+ individuals demonstrated reduced naïve (22.1% of subjects) and Treg (35.8%) frequencies and elevated IRC (29.5%). Of the 103 subjects, 48(46.6%) progressed. Individually, T cell subsets were weakly predictive (AUC between 0.63 and 0.66), although the presence of 2 T cell abnormalities had high specificity. Three models were compared: model-1 used T cell subsets only, model-2 used previously published clinical parameters, model-3 combined clinical data and T cell data. Model-3 performed the best (AUC 0.79 (95% CI 0.70 to 0.89)) compared with model-1 (0.75 (0.65 to 0.86)) and particularly with model-2 (0.62 (0.54 to 0.76)) demonstrating the added value of T cell subsets. Time to progression differed significantly between high-risk, moderate-risk and low-risk groups from model-3 (p=0.001, median 15.4 months, 25.8 months and 63.4 months, respectively). Conclusions T cell subset dysregulation in ACPA+ individuals predates the onset of IA, predicts the risk and faster progression to IA, with added value over previously published clinical predictors of progression.

Age-related Changes in Bone Marrow Mesenchymal Stromal Cells: A Potential Impact on Osteoporosis and Osteoarthritis Development

Aging at the cellular level is a complex process resulting from accumulation of various damages leading to functional impairment and a reduced quality of life at the level of the organism. With a rise in the elderly population, the worldwide incidence of osteoporosis (OP) and osteoarthritis (OA) has increased in the past few decades. A decline in the number and “fitness” of mesenchymal stromal cells (MSCs) in the bone marrow (BM) niche has been suggested as one of the factors contributing to bone abnormalities in OP and OA. It is well recognized that MSCs in vitro acquire culture-induced aging features such as gradual telomere shortening, increased numbers of senescent cells, and reduced resistance to oxidative stress as a result of serial population doublings. In contrast, there is only limited evidence that human BM-MSCs “age” similarly in vivo. This review compares the various aspects of in vitro and in vivo MSC aging and suggests how our current knowledge on rejuvenating cultured MSCs could be applied to develop future strategies to target altered bone formation processes in OP and OA.