IL-40 is up-regulated in the synovial fluid and cartilage of osteoarthritis patients and contributes to the alteration of chondrocytes phenotype in vitro.

INTRODUCTION: IL-40 is a novel cytokine associated with autoimmune connective tissue disorders such as rheumatoid arthritis (RA) or Sjögren syndrome. We have previously shown an accumulation of IL-40 in the RA joint and its expression by immune cells and fibroblasts. Therefore, we aimed to assess the role of IL-40 in association with hyaline cartilage and chondrocyte activity. METHODS: Immunohistochemistry was employed to detect IL-40 in paired samples of loaded and unloaded regions of osteoarthritis (OA) cartilage (n=5). Synovial fluid IL-40 was analysed by ELISA in OA (n=31) and control individuals after knee injury (n=34). The impact of IL-40 on chondrocytes was tested in vitro. RESULTS: IL-40 was found in chondrocytes of the superficial zone of the OA cartilage, both in loaded and unloaded explants. Additionally, only biopsies from loaded explants showed significant IL-40 positivity in transitional zone chondrocytes. Levels of IL-40 were significantly elevated in the synovial fluid from OA patients compared to controls (p<0.0009) and correlated with synovial fluid leukocyte counts in OA (r=0.444, p=0.014). Chondrocytes exposed to IL-40 dose dependently increased in the secretion of pro-inflammatory cytokines IL-6 (p<0.0001) and IL-8 (p=0.004). Moreover, a dose dependent up-regulation of matrix degrading metalloproteinases MMP-1 (p=0.004), MMP-3 (p=0.031) and MMP-13 (p=0.0002) upon IL-40 treatment was observed in contrast to untreated chondrocytes. CONCLUSION: This study is the first to demonstrate the accumulation of IL-40 in OA cartilage and its up-regulation in the synovial fluid of OA patients compared to controls. In addition, extracellular IL-40 appears to play a role in promoting inflammation and cartilage destruction by driving chondrocyte behaviour towards a more aggressive phenotype.

Serum biomarkers and their relationship to axial spondyloarthritis associated with inflammatory bowel diseases.

Spondyloarthritis (SpA) constitute a group of chronic inflammatory immune-mediated rheumatic diseases characterized by genetic, clinical, and radiological features. Recent efforts have concentrated on identifying biomarkers linked to axial SpA associated with inflammatory bowel disease (IBD), offering predictive insights into disease onset, activity, and progression. Genetically, the significance of the HLA-B27 antigen is notably diminished in ankylosing spondylitis (AS) associated with IBD, but is heightened in concurrent sacroiliitis. Similarly, certain polymorphisms of endoplasmic reticulum aminopeptidase (ERAP-1) appear to be involved. Carriage of variant NOD2/CARD15 polymorphisms has been demonstrated to correlate with the risk of subclinical intestinal inflammation in AS. Biomarkers indicative of pro-inflammatory activity, including C-reactive protein (CRP) along with erythrocyte sedimentation rate (ESR), are among the consistent predictive biomarkers of disease progression. Nevertheless, these markers are not without limitations and exhibit relatively low sensitivity. Other promising markers encompass IL-6, serum calprotectin (s-CLP), serum amyloid (SAA), as well as biomarkers regulating bone formation such as metalloproteinase-3 (MMP-3) and Dickkopf-related protein 1 (DKK-1). Additional candidate indicators of structural changes in SpA patients include matrix metalloproteinase-3 (MMP-3), vascular endothelial growth factor (VEGF), tenascin C (TNC), and CD74 IgG. Fecal caprotein (f-CLP) levels over long-term follow-up of AS patients have demonstrated predictive value in anticipating the development of IBD. Serologic antibodies characteristic of IBD (ASCA, ANCA) have also been compared; however, results exhibit variability. In this review, we will focus on biomarkers associated with both axial SpA and idiopathic intestinal inflammation, notably enteropathic spondyloarthritis.

Circulating miRNAs in hand osteoarthritis.

OBJECTIVE: Hand osteoarthritis (OA) is a frequent musculoskeletal disorder with an increasing prevalence during ageing. This study aimed to evaluate circulating microRNAs (miRNAs) in the plasma of patients with hand OA compared with age- and sex-matched healthy control subjects. METHODS: In total, 238 participants (96 with erosive and 73 with non-erosive hand OA patients and 69 healthy control subjects) were included in this study. All patients underwent clinical examinations, including self-reported measures (AUSCAN and Algofunctional index). Radiographs of both hands were scored with the Kallman scale. The profile of miRNAs in plasma was screened using TaqMan™ Low-Density Array, and candidate miRNAs were validated on two quantitative real-time PCR (qRT-PCR) systems (QuantStudio and SmartChip). RESULTS: Of all the 754 miRNAs, 40 miRNAs were different between hand OA patients and healthy control subjects in the screening cohort. Following the two-phase validation process, three miRNAs (miR-23a-3p, miR-146a-5p, and miR-652-3p) were increased in patients with hand OA compared with healthy control subjects and were associated with the AUSCAN sum score and AUSCAN pain. Furthermore, an inverse correlation of miR-222-3p with the Kallman radiographic score was found. The expression of miRNAs did not differ between erosive and non-erosive hand OA. CONCLUSION: The profile of circulating miRNAs could unveil candidate biomarkers associated with hand OA symptoms. Longitudinal studies are required to determine the role of miRNAs in hand OA.

Circulating miR-145 as a marker of therapeutic response to anti-TNF therapy in patients with ankylosing spondylitis.

Circulating miRNAs appear promising therapeutic and prognostic biomarkers. We aimed to investigate the predictive value of circulating miRNAs on the disease outcome following anti-TNF therapy in patients with ankylosing spondylitis (AS). Our study included 19 AS patients assessed at baseline (M0), after three (M3) and twelve months (M12) of therapy. Total RNA was isolated from plasma. A comprehensive analysis of 380 miRNAs using TaqMan Low Density Array (TLDA) was followed by a single assay validation of selected miRNAs. All AS patients had high baseline disease activity and an excellent response to anti-TNF therapy at M3 and M12. TLDA analysis revealed the dysregulation of 17 circulating miRNAs, including miR-145. Single assay validation confirmed that miR-145 is significantly downregulated at M3 compared to baseline. The decrease in the levels of miR-145 from M0 to M3 negatively correlated with the change in BASDAI from M0 to M3; and positively correlated with disease activity improvement from M3 to M12 as per BASDAI and ASDAS. The predictive value of the early change in miR-145 and levels of miR-145 at M3 were further validated by Receiver operating curves analysis. We show thatthe early change in circulating miR-145 may be a predictor for the future outcome ofAS patients treated with TNF inhibitors. Patients with a more significant decrease in miR-145 levels may show further significant improvement of disease activity after 12 months. Monitoring the expression of miR-145 in plasma in AS patients may, therefore, influence our therapeutic decision-making.

Elevated Tenascin-C Serum Levels in Patients With Axial Spondyloarthritis.

This study aimed to examine serum tenascin C (TNC) in different subsets of axial spondyloarthritis (axSpA) patients. Sixty-one patients fulfilling the Assessment of SpondyloArthritis international Society classification criteria for axSpA and 20 healthy subjects (HS) were included in study. Based on imaging, patients were classified as non-radiographic (n=16) and radiographic (n=45) axSpA. TNC serum levels were determined by ELISA. Disease-related factors including the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and C-reactive protein (CRP) levels, were determined. TNC levels were elevated in axSpA patients [535.3 (457.7-677.2) ng/ml] compared to HS [432.1 (329.1-565.9) ng/ml, p=0.007]. Dividing axSpA into radiographic and non-radiographic subsets, the difference in TNC was observed between the radiographic subset and HS [535.3 (434.5-677.2) vs. 432.1 (329.1-565.9) ng/ml, p=0.022]. TNC levels did not correlate with disease activity measures (serum CRP or BASDAI). Nevertheless, the weak correlation of TNC levels with different disease stages (r=0.25, p=0.025) was found, with the highest levels in patients with syndesmophytes. TNC levels are elevated across various subsets of axSpA, and although not related to systemic disease activity, TNC levels might reflect chronic structural spinal changes in axSpA patients. However, its specific role in bone metabolism should be elucidated in further studies.

Is serum TWEAK a useful biomarker of neuropsychiatric systemic lupus erythematosus?

The aim of this study was to determine the role of the tumor necrosis factor like weak inducer of apoptosis (TWEAK) as a serum biomarker of neuropsychiatric involvement in systemic lupus erythematosus (NPSLE). Levels of TWEAK levels were measured in sera of 92 patients with systemic lupus erythematosus (SLE), including 28 patients with neuropsychiatric lupus, and in 59 healthy controls using ELISA. All SLE patients underwent rheumatological, neurological and psychiatric assessment. We found no significant differences in TWEAK levels, between SLE patients and the healthy controls (p=0.2411). Similarly, no difference was observed between subgroup of NPSLE and healthy controls (p=0.7658). The mean SLE disease activity (SLEDAI) was 13.25. No correlations between TWEAK levels with disease activity (SLEDAI, r=0.2113, p=0.2805) or the most common NPSLE manifestations such as headache (r=0.2079), seizures (r=0.1101), cerebrovascular disease (r= 0.2347), cognitive dysfunction (r=0.1597) and anxiety (r=0.1397) were observed. Our data do not support the use of serum TWEAK as a discriminating biomarker for NPSLE. The role of the TWEAK in NPSLE remains to be investigated.

Decrease in serum interleukin-21 levels is associated with disease activity improvement in patients with recent-onset rheumatoid arthritis.

Interleukin-21 (IL-21) plays an important role in the pathogenesis of rheumatoid arthritis (RA). The aim of our study was to assess serum levels of IL-21 in patients with recent-onset RA in relation to disease activity and response to treatment. We analyzed serum levels of IL-21 in 51 RA patients, both before and 12 weeks after the initiation of treatment and in 36 healthy individuals. Disease activity was assessed at baseline and at weeks 12 and 24 using the Disease Activity Score for 28 joints, serum levels of C-reactive protein, and the total swollen joint count. We found that IL-21 levels were not increased in patients with recent-onset RA compared with healthy controls, but they had significantly decreased from baseline to week 12 during treatment. Baseline levels of IL-21 significantly correlated with measures of disease activity (p<0.02 for all). Although IL-21 levels did not predict achievement of remission, decrease in IL-21 levels correlated with improvement in disease activity after 12 weeks (p<0.02) and also after 24 weeks (p<0.04) of treatment. Our data suggest that circulating IL-21 levels may serve as a biomarker of disease activity and better outcome in early phase of RA.

[Regular exercise training decreases asymmetric dimethylarginine after kidney transplantation]. / Casný pohybový rezim snizuje asymetrický dimetylarginin po transplantaci ledviny.

BACKGROUND: Levels of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine are elevated in patients undergoing kidney transplantation and may contribute to vascular complications. In this study we tested the hypothesis that elevated asymmetric dimethylarginine can be reduced in patients after kidney transplantation by early regular physical exercise. Selected cytokines and metabolic parameters were also analysed. METHODS: Plasma samples for analysis of asymmetric dimethylarginine, adiponectin, leptin, soluble leptin receptor, resistin, visfatin, CRP, TNFα and selected metabolic parameters were obtained from randomly selected sixty eight patients after kidney transplantation who agreed to participate in a supervised aerobic exercise program for six months. Samples were collected before the training began (one month after surgery with stabilized graft function) and at six months after initiation. Sixty transplant patients matched for age, sex, HLA typing, duration of previous dialysis, history of cardiovascular disease and immunosupression regimen who did not exercise regularly and did not participate in the training program were examined as controls. RESULTS: There were no differences in elevated asymmetric dimethylarginine levels between both groups before the training program began. After six months of exercise, asymmetric dimethylarginine concentration in the exercising group I significantly decreased (3.5 ± 0.45 vs 2.11 ± 0.35 µmol/L, P < 0.01) and was also significantly lower comparing to non-exercising group II (2.11 ± 0.23 vs 3.25 ± 0.34 µmol/L, P < 0.01). We found significant changes in exercising group I: adiponectin (15.4 ± 6.6 vs 22.3 ± 6.2 mg/mL, P < 0.01), leptin (51.3 ± 11.2 vs 20.3 ± 9.2 ng/L, P < 0.01), soluble leptin receptor (24.6 ± 8.4 vs 46.1 ± 11.4 U/mL, P < 0.01), resistin (20.8 ± 10.1 vs 14.6 ± 6.4 mg/mL, P < 0.025) and visfatin (1.8 ± 0.2 vs 1.2 ± 0.01 ng/mL, P < 0.05). Blood lipids, HbA1c, CRP and TNFα were also affected by the training program. CONCLUSIONS: Elevated asymmetric dimethylarginine level, selected adipocytokines and proinflammatory cytokines in patients after kidney transplantation were significantly influenced by early regular exercise. This regimen may decrease cardiovascular risk in patients after kidney transplantation.

Novel adipokine fibroblast growth factor 21 is increased in rheumatoid arthritis.

Fibroblast growth factor-21 (FGF-21) has been recently characterized as a new adipokine. The aim of this study was to assess FGF-21 levels in patients with rheumatoid arthritis (RA) and osteoarthritis (OA) and to study the relationship between FGF-21, disease activity and metabolic status. The levels of FGF-21 in serum and synovial fluid samples from 38 patients with RA and 42 control individuals with OA were determined by ELISA. Patients were assessed for disease activity using the disease activity score (DAS28), a serum glucose and lipid profile. Age, sex and BMI-adjusted FGF-21 levels in the serum (p=0.024) and synovial fluid (p=0.010) samples were significantly higher in patients with RA when compared with OA. The levels of FGF-21 in the serum significantly correlated with the levels in the synovial fluid. Serum and synovial fluid FGF-21 levels adjusted for confounders correlated positively with C-reactive protein. The levels of FGF-21 were positively correlated with BMI in patients with RA; however, the levels were not associated with disease activity or lipid profiles. Furthermore, serum FGF-21 levels were significantly higher in seropositive compared with seronegative RA patients. This work shows that patients with seropositive RA have increased levels of FGF-21. The results suggest that FGF-21 is related to BMI but not disease activity or lipid profiles in patients with RA.

Low circulating Dickkopf-1 and its link with severity of spinal involvement in diffuse idiopathic skeletal hyperostosis.

OBJECTIVE: Dickkopf-1 (DKK-1) is an inhibitor of osteoblastogenesis, and its lower levels are linked to new bone formation. The aim of this study was therefore to explore serum levels of DKK-1 and to evaluate DKK-1's association with the severity of spinal involvement in diffuse idiopathic skeletal hyperostosis (DISH). METHODS: Serum levels of total and functional DKK-1 and C-reactive protein (CRP) were measured in 37 patients with DISH and 22 healthy age and sex-matched controls. Plain radiographs of the cervical and thoracic spine were performed, and the diagnosis of DISH was defined using the Resnick criteria. Patients were divided into three groups based on spinal involvement. Bone mineral density (BMD) and bone turnover markers were evaluated in patients with DISH. RESULTS: The levels of total serum DKK-1 were significantly lower in patients with DISH than in healthy controls (p<0.0001). Importantly, low serum levels of DKK-1 were associated with more severe spinal involvement in DISH, independent of age, sex, disease duration, CRP, bone turnover markers or BMD. However, these findings were less significant for functional DKK-1. CONCLUSION: These observations indicate that DKK-1 may play a significant role in bone formation during DISH.

Elevated prolactin levels in patients with rheumatoid arthritis: association with disease activity and structural damage.

OBJECTIVES: Prolactin (PRL) is a hormone with cytokine-like activities that has been demonstrated to be involved in immune responses. However, there are inconsistent results related to the role of PRL in rheumatoid arthritis (RA). Therefore, the aim of this study was to evaluate the levels of PRL in serum and synovial fluid in patients with RA and osteoarthritis (OA) and examine whether PRL might be associated with laboratory and clinical disease activity of RA. METHODS: A total of 29 patients with RA and 26 patients with OA were included in the study. The concentration of PRL in the serum and synovial fluid was measured by immunoradiometric assays, and the levels of serum anti-citrullinated protein/peptide autoantibodies (ACPA) and IgM rheumatoid factor (IgM-RF) were analysed by ELISA. Disease activity score (DAS 28) and radiological (Larsen) score were assessed. RESULTS: The levels of PRL in serum (299.55±27.28 vs. 230.59±16.61 mIU/l, p=0.041) as well as in synovial fluid (338.85±33.49 vs. 245.97±21.88 mIU/l, p=0.024) were significantly higher in patients with RA than in patients with OA. A moderate correlation was found between disease activity of RA and levels of PRL in synovial fluid (r=0.485, p=0.010) and the serum PRL levels correlated significantly with the total Larsen score (r=0.484, p=0.014). CONCLUSIONS: The findings of increased prolactin levels in patients with RA lead to the assumption that prolactin may play a role in disease severity and the process of joint damage in RA.

Surface modification of cyclic olefin copolymers for osteochondral defect repair can increase pro-destructive potential of human chondrocytes in vitro.

Materials on the basis of cycloolefin copolymers (COC) are suitable for subchondral defect repairs. The objective of this study was to evaluate the influence of surface modification of COC and COC/LLDPE blends on the viability and gene expression of chondrocytes. Human chondrocytes were incubated on the surface of the studied materials. Half of the materials were plasmatically modified with a subsequent type II collagen application. The gene expression of matrix metalloproteinases (MMP-1,-3,-13), pro-inflammatory cytokines (IL-1, TNF-alpha) and apoptotic molecules (BAX, Bcl-2) was evaluated using quantitative Taq-Man PCR after 48 h incubation. Chondrocyte viability was evaluated by the MTT test after 2, 4 and 8 days of incubation. The synthesis of MMPs was measured by ELISA assay in cell culture medium after 48 h of incubation. Chondrocytes incubated on plasmatically modified in contrast to unmodified materials demonstrated significantly increased gene expression of IL-1 (p<0.05), MMP-1 and MMP-3 (p<0.05 for both comparisons) as well as MMP-13 (p<0.001). Increased gene expression was confirmed by significantly increased production of active forms of particular MMPs into the cell culture medium. Unlike surface unmodified polymers, the modified materials showed time-dependent reduction of chondrocyte viability. The gene expression of TNF-alpha and apoptotic molecules by chondrocytes was not significantly changed by different materials. Cycloolefin copolymers and their blends may represent suitable materials for tissue engineering, however, their surface modification followed by collagen type II application may, at least under in vitro conditions, reduce the viability of chondrocytes and induce their pro-destructive behavior. The potential benefit or disadvantage of surface modifications of materials for osteochondral defect repairs needs to be further elucidated.

Serum hyaluronic acid as a potential marker with a predictive value for further radiographic progression of hand osteoarthritis.

OBJECTIVE: To compare serum levels of hyaluronic acid (HA) between patients with erosive and non-erosive hand osteoarthritis (HOA), and investigate its association with morphological changes and radiographic progression over 2 years. METHODS: Fifty-five women with erosive and 33 women with non-erosive HOA were included in this study. All underwent clinical examination, which included assessment of pain, swelling, deformity and deviation of small hand joints and completed health assessment questionnaires. Serum levels of HA were measured by ELISA. Three-phase bone scintigraphy was performed at baseline. Radiographs of both hands were performed at baseline and after 2 years and scored according Kallman grading scale. RESULTS: Serum levels of HA were significantly higher in patients with erosive than with non-erosive HOA (P<0.01). It correlated significantly with the number of hand joints with deviations and deformities. HA adjusted for age and disease duration significantly correlated with radiographs at baseline and after 2 years in all patients with HOA (r=0.560 and r=0.542, P<0.01 for both correlations). Although there was an association between HA and radiographic score in erosive disease, after adjustment for confounders it remained no longer significant. HA adjusted for confounders correlated significantly with the late phase in all patients with HOA (r=0.412, P<0.01) and in patients with erosive disease (r=0.320, P<0.05). CONCLUSION: HA is increased in patients with erosive HOA and could be proposed as a surrogate marker with a predictive value for further radiographic progression of HOA in general. Further investigation is necessary to confirm these results.

Increasing the infliximab dose in rheumatoid arthritis patients: a randomised, double blind study failed to confirm its efficacy.

OBJECTIVE: To evaluate the effect of infliximab dose escalation in incomplete responders in a randomised controlled trial. METHODS: 141 rheumatoid arthritis (RA) patients treated with infliximab for 12 months (3 mg/kg; intervals 0, 2, 6 and then 8 weeks) who responded to the drug (disease activity score in 28 joints (DAS28) decrease >1.2) but who were not in remission (DAS28 >2.6) were enrolled into the study. Patients were randomly assigned into arm A, 3 mg/kg, and arm B, 5 mg/kg infliximab every 8 weeks. Outcome measures included the DAS28, its components and C-reactive protein (CRP). RESULTS: There were no significant differences in changes in the DAS28, its components, or CRP in patients in arms A and B during the 12 months of treatment. All patients showed a DAS28 decrease greater than 0.6 after 28 weeks. Eleven patients interrupted therapy in arm A and 14 in arm B. Infusion reactions and non-serious adverse events were observed in 4.2% and 28.2% of arm A patients and in 7.2% and 47.8% of arm B patients. The frequency of serious adverse events was comparable between arms A and B (16.9% and 15.9%, respectively), and the frequency of serious infections was not significantly greater in the higher dose group (5.8%) than in the lower dose group (5.6%). CONCLUSIONS: In this setting, increasing the infliximab dose from 3 mg/kg to 5 mg/kg in RA patients with residual disease activity did not improve efficacy but moderately increased toxicity. These data indicate that a switch to another biological treatment would be a more appropriate strategy in incomplete responders.

The lack of correlation between the increased frequency of allele IL-1RN*2 of interleukin-1 receptor antagonist gene in Czech patients with knee osteoarthritis and the markers of cartilage degradation.

Primary OA is a common multifactorial disease with not fully clarified molecular factors influencing the development of the disease. Among factors disturbing the cartilage integrity are cytokines, such as IL-1, which can stimulate proteinases, resulting in the cartilage destruction. In this regard, IL-1RA competing with IL-1 for binding to its receptor may act as an inhibitor of cartilage breakdown. Because of the possible functional implications, we tested VNTR polymorphism in the second intron of the IL-1RN gene as a putative factor of susceptibility to knee OA. Fifty patients with primary knee OA (diagnosed according to ACR criteria) and 170 healthy controls were included into the study. PCR using primers flanking the VNTR region containing variable numbers of an 86-bp tandem repeat was employed to test the hypothesis. An increased frequency and carriage rate of the IL-1RN*2 allele was found in OA patients in comparison with controls (28 % vs. 15 %, P = 0.0013, OR = 2.97; 95% CI 1.55-5.68 for frequency; 52.5 % vs. 25.3 %, P = 0.0019, OR = 2.95; 95% CI 1.54-5.68 for carriage rate). In addition, a higher frequency of genotype IL-1RN*1/*2 in OA patients was observed as compared with controls (42 % vs. 20.6 %, P = 0.0032, OR = 2.79; 95% CI 1.42-5.48). These results suggest that the IL-1RN*2 allele might represent a factor of susceptibility to OA; however, no correlation between this allele and the markers of cartilage degradation was found.

The metastasis associated protein S100A4: a potential novel link to inflammation and consequent aggressive behaviour of rheumatoid arthritis synovial fibroblasts.

The metastasis-associated protein S100A4 belongs to the large family of S100 calcium-binding proteins that appear to play regulatory roles in diverse biological activities. Moreover, a prognostic role of S100A4 has been suggested for patients with several types of cancer. Cancer promoting properties for S100A4 have been demonstrated, particularly through its regulation of cell motility, proliferation and apoptosis, as well as by stimulation of angiogenesis and remodelling of the extracellular matrix. Increased expression of S100A4 mRNA has been detected in proliferating synovial fibroblasts in rheumatoid arthritis. Furthermore, strong upregulation of the S100A4 protein in rheumatoid arthritis synovial tissue compared with osteoarthritis and control tissues has been demonstrated recently, especially at sites of joint invasion. Several immune and vascular cells were also identified to be producing S100A4 within the synovium. The local upregulation of S100A4 was accompanied by high plasma and synovial fluid concentrations of the S100A4 protein existing in the bioactive oligomeric form in patients with rheumatoid arthritis. Consistent with data from cancer studies, the extracellular S100A4 oligomer appears to be involved in regulation of several matrix-degrading enzymes and modulation of the transcriptional activation function of the tumour suppressor protein p53 in rheumatoid arthritis synovial fibroblasts. Taken together, one can speculate that increased S100A4 protein in circulation and locally at sites of inflammation, particularly at sites of joint destruction, might be linked to the process of aggressive fibroblast behaviour contributing to the pathogenesis of chronic autoinflammatory diseases such as rheumatoid arthritis.

Advanced glycation end-product pentosidine is not a relevant marker of disease activity in patients with rheumatoid arthritis.

Advanced glycation end-product (AGE) pentosidine has previously been demonstrated in different tissues and body fluids. It was suggested as a novel marker for evaluating the pathologic activity in rheumatoid arthritis (RA). In this study we analyzed the relation between pentosidine and markers of inflammation, cartilage turnover, immune response, and disease status of RA. Using HPLC, we analyzed pentosidine in serum and synovial fluid from 39 patients with RA and in serum from 38 healthy controls. Cartilage oligomeric matrix protein (COMP) and antibodies to CCP (anti-CCP) were measured by ELISA. Clinical disease status was assessed by Disease Activity Score 28 (DAS 28) and functional status by Health Assessment Questionnaire (HAQ). We demonstrated significantly higher serum levels of pentosidine in RA patients in comparison with controls. Pentosidine in serum significantly correlated with pentosidine in synovial fluid. Serum pentosidine levels were associated with erythrocyte sedimentation rate (p<0.03) but not with CRP, COMP, anti-CCP antibodies, DAS 28, or HAQ. In contrast to previous studies, we could not show any correlation of pentosidine levels with inflammatory status, clinical disease activity, markers of immune response, or cartilage breakdown. However, AGEs can be suggested as important players participating in joint destruction rather than markers of disease activity.

Resistin in rheumatoid arthritis synovial tissue, synovial fluid and serum.

BACKGROUND: Resistin is a newly identified adipocytokine which has demonstrated links between obesity and insulin resistance in rodents. In humans, proinflammatory properties of resistin are superior to its insulin resistance-inducing effects. OBJECTIVES: To assess resistin expression in synovial tissues, serum and synovial fluid from patients with rheumatoid arthritis, osteoarthritis and spondylarthropathies (SpA), and to study its relationship with inflammatory status and rheumatoid arthritis disease activity. METHODS: Resistin expression and localisation in synovial tissue was determined by immunohistochemistry and confocal microscopy. Serum and synovial fluid resistin, leptin, interleukin (IL)1beta, IL6, IL8, tumour necrosis factor alpha, and monocyte chemoattractant protein-1 levels were measured. The clinical activity of patients with rheumatoid arthritis was assessed according to the 28 joint count Disease Activity Score (DAS28). RESULTS: Resistin was detected in the synovium in both rheumatoid arthritis and osteoarthritis. Staining in the sublining layer was more intensive in patients with rheumatoid arthritis compared with those with osteoarthritis. In rheumatoid arthritis, macrophages (CD68), B lymphocytes (CD20) and plasma cells (CD138) but not T lymphocytes (CD3) showed colocalisation with resistin. Synovial fluid resistin was higher in patients with rheumatoid arthritis than in those with SpA or osteoarthritis (both p<0.001). In patients with rheumatoid arthritis and SpA, serum resistin levels were higher than those with osteoarthritis (p<0.01). Increased serum resistin in patients with rheumatoid arthritis correlated with both CRP (r=0.53, p<0.02), and DAS28 (r=0.44, p<0.05), but not with selected (adipo) cytokines. CONCLUSION: The upregulated resistin at local sites of inflammation and the link between serum resistin, inflammation and disease activity suggest a role for resistin in the pathogenesis of rheumatoid arthritis.

S100A4 is expressed at site of invasion in rheumatoid arthritis synovium and modulates production of matrix metalloproteinases.

The metastasis-associated protein S100A4 promotes the progression of cancer by regulating the remodelling of the extracellular matrix. The expression of S100A4 in vivo is shown and the functional role of S100A4 in the pathogenesis of osteoarthritis and rheumatoid arthritisis is explored. The expression of S100A4 in rheumatoid arthritis, osteoarthritis and normal synovial tissues was determined by immunohistochemistry. The expression of matrix metalloproteinase (MMP) mRNA was measured in rheumatoid arthritis and osteoarthritis synovial fibroblasts treated and untreated with S100A4 oligomer by real-time polymerase chain reaction. Levels of released MMPs were confirmed by ELISA in cell culture supernatants. S100A4 protein was expressed in rheumatoid arthritis and osteoarthritis synovial tissues, in contrast with normal synovium. S100A4 up regulated MMP-3 mRNA in rheumatoid arthritis synovial fluid, with a peak after 6 h. This resulted in release of MMP-3 protein. MMP-1, MMP-9 and MMP-13 mRNA were also up regulated in synovial fluid, but with different kinetics. MMP-14 mRNA showed no change. Thus, S100A4 protein is expressed in synovial tissues of patients with rheumatoid arthritis and osteoarthritis in contrast with healthy people. It induces the expression and release of MMP-3 and other MMPs from synovial fluid. The data suggest that S100A4-producing cells could be involved in the pathogenesis of osteoarthritis and rheumatoid arthritis, including pannus formation and joint destruction.