Detection of stromelysin in synovial fluid and serum from patients with rheumatoid arthritis and osteoarthritis

Fibroblast-like synoviocytes orchestrate daily rhythmic inflammation in arthritis

Rheumatoid arthritis is a chronic inflammatory disease that shows characteristic diurnal variation in symptom severity, where joint resident fibroblast-like synoviocytes (FLS) act as important mediators of arthritis pathology. We investigate the role of FLS circadian clock function in directing rhythmic joint inflammation in a murine model of inflammatory arthritis. We demonstrate FLS time-of-day-dependent gene expression is attenuated in arthritic joints, except for a subset of disease-modifying genes. The deletion of essential clock gene Bmal1 in FLS reduced susceptibility to collagen-induced arthritis but did not impact symptomatic severity in affected mice. Notably, FLS Bmal1 deletion resulted in loss of diurnal expression of disease-modulating genes across the joint, and elevated production of MMP3, a prognostic marker of joint damage in inflammatory arthritis. This work identifies the FLS circadian clock as an influential driver of daily oscillations in joint inflammation, and a potential regulator of destructive pathology in chronic inflammatory arthritis.

Cartilage and bone loss in premenopausal women with rheumatoid arthritis: Radiological and laboratory assessments

INTRODUCTION

To investigate the radiological and laboratory features of bone and cartilage losses in premenopausal women with rheumatoid arthritis (RA).

METHODS

This case-control study is the continuation of a study that was conducted on 48 women with RA and 48 matched healthy volunteers. All RA patients were previously subjected to clinical examination, disease activity assessment using the 28-joint Disease Activity Score (DAS28) and Clinical Disease Activity Index (CDAI), serological tests, dual-energy X-ray absorptiometry measuring bone mineral density (BMD), and plain X-ray of both hands. Added to these, matrix metalloproteinase 3 (MMP-3) and cartilage oligomeric matrix protein (COMP) were measured by enzyme-linked immunosorbent assay.

RESULTS

There were statistically significant differences between patients and controls regarding COMP and MMP-3, being higher in patients (p < .001). COMP and MMP-3 have significant positive correlation with serum levels of anti-cyclic citrullinated peptide (anti-CCP) and anti-carbamylated protein (anti-CarP). The original Sharp erosion score was positively correlated with the serum level of the studied antibodies and disease duration, but no significant correlation was found with either COMP, MMP-3, or DAS-28. Spine BMD and Z score were negatively correlated with disease activity and anti-CarP. There were significant positive relationhsips between indices of local cartilage and bone loss and the indices of systemic bone loss. MMP-3 had no correlation with indices of local cartilage and bone loss and disease activity scores.

CONCLUSIONS

The pathogenic mechanism of hand joint damage involved the three studied autoantibodies namely, rheumatoid factor, anti-CCP and anti-CarP antibodies. Anti-CarP antibody was involved in the reduction of BMD of the spine. The association between systemic osteoporosis and hand joint damage pointed to a common pathogenic mechanism.

Matrix metalloproteinases in arthritis: towards precision medicine

Proteolysis of structural molecules of the extracellular matrix (ECM) is an irreversible post-translational modification in all arthropathies. Common joint disorders, including osteoarthritis and rheumatoid arthritis, have been associated with increased levels of matrix remodelling enzymes, including matrix metalloproteinases (MMPs). MMPs, in concert with other host proteinases and glycanases, destroy proteoglycans, collagens and other ECM molecules. MMPs may also control joint remodelling indirectly by signalling through cell-surface receptors or by proteolysis of cytokines and receptor molecules. After synthesis as pro-forms, MMPs can be activated by various types of post-translational modifications, including proteolysis. Once activated, MMPs are controlled by general and specific tissue inhibitors of metalloproteinases (TIMPs). In rheumatoid arthritis, proteolysis of the ECM results in so-called remnant epitopes that enhance and perpetuate autoimmune processes in susceptible hosts. In osteoarthritis, the considerable production of MMP-13 by chondrocytes, often concurrent with mechanical overload, is a key event. Hence, information about the regulation, timing, localization and activities of MMPs in specific disease phases and arthritic entities will help to develop better diagnostics. Insights into beneficial and detrimental effects of MMPs on joint tissue inflammation are also necessary to plan and execute (pre)clinical studies for better therapy and precision medicine with MMP inhibitors. With the advances in proteomics and single-cell transcriptomics, two critical points need attention: neglected neutrophil MMP biology, and the analysis of net proteolytic activities as the result of balances between MMPs and their inhibitors.

Use of some bone-related cytokines as predictors for rheumatoid arthritis severity by neural network analysis

Background. Rheumatoid arthritis (RA) is characterized by synovial membrane inflammation that results in joint damage. Many earlier studies have measured cytokines for a better diagnosis of RA. In the present study, three bone biomarkers (osteopontin, Stromelysin-1 (MMP3), and vascular endothelial growth factor-A (VEGF)) are examined for their ability to estimate the severity of disease by using artificial neural network (NN) analysis and regression analysis. Methods: The study enrolled 87 RA patients and 44 healthy control subjects. The biomarkers were measured by the enzyme-linked immunosorbent assay (ELISA) technique. Disease Activity Score (28 joints) and C-reactive protein (CRP) (DAS28-CRP) was calculated by using (DAS28-CRP) calculator. The patients with DAS28-CRP5.1 are considered as having high disease activity (HDA). While patients group with DAS28-CRP5.1 are considered as moderate disease activity (MDA). The neural network (NN) analysis was used for the differentiation between groups. Results. Results showed that the most sensitive predictor for high disease activity (HDA) of RA is MMP3, followed by osteopontin and VEGF. These three biomarkers can differentiate significantly between HDA and moderate disease activity (MDA) with a relatively high size effect (Partial 2=0.323, p0.001). HDA group has a significantly higher MMP3, CRP, RF, and anti-citrullinated protein antibodies (ACPA) than the MDA group. Conclusions. The use of the NN analysis indicated that the measured biomarkers help predict the HDA state in RA patients. MMP3 and osteopontin are diagnostic biomarkers for the severity of RA disease and related to many disease-related characteristics with a sensitivity of 88.9% and specificity of 68.4%.

Concentration of Selected Metalloproteinases and Osteocalcin in the Serum and Synovial Fluid of Obese Women with Advanced Knee Osteoarthritis

The aim of the study was to evaluate the levels of selected MMPs (matrix metalloproteinases) and osteocalcin in the serum and synovial fluid of obese women with osteoarthritis and their correlations with clinical status. The studied group consisted of 39 overweight females undergoing primary total knee arthroplasty due to osteoarthritis (OA). The staging of knee OA was evaluated according to the Ahlbӓck and Kellgren–Lawrence scores. Synovial fluid and peripheral blood samples were obtained. The levels of selected MMPs and osteocalcin were assessed using commercial ELISA kits. The mean value of MMP3 was significantly higher in patients with more advanced disease in both serum (p = 0.0067) and synovial fluid (p = 0.0328). The pro-MMP13 level tended to be higher in synovial fluid in the case of more advanced stages (p = 0.0882), with no tendency regarding the serum level (p = 0.9595). The synovial level of pro-MMP1 was significantly correlated with the synovial concentration of MMP9 and MMP3. The synovial level of MMP9 also showed a significant correlation with the synovial level of MMP3 and pro-MMP13. Furthermore, it was found that the serum level of MMP3 was significantly correlated with the synovial pro-MMP13 level. A correlation between the osteocalcin level in serum and its synovial level was determined. The serum MMP9 level showed a significant correlation with BMI, whereas the synovial MMP9 level was notably correlated with age. Our results showed that the levels of MMP3, MMP9, and pro-MMP13 increased in more advanced radiological stages of OA, indicating the underlying inflammatory process of OA.

Proteoform Analysis of Matrix Metalloproteinase-9/Gelatinase B and Discovery of Its Citrullination in Rheumatoid Arthritis Synovial Fluids

Objectives

To explore posttranslational modifications (PTMs), including proteolytic activation, multimerization, complex formation and citrullination of gelatinases, in particular of gelatinase B/MMP-9, and to detect in gelatin-Sepharose affinity-purified synovial fluids, the presence of specific MMP proteoforms in relation to arthritis.

Methods

Latent, activated, complexed and truncated gelatinase-A/MMP-2 and gelatinase B/MMP-9 proteoforms were detected with the use of zymography analysis to compare specific levels, with substrate conversion assays, to test net proteolytic activities and by Western blot analysis to decipher truncation variants. Citrullination was detected with enhanced sensitivity, by the use of a new monoclonal antibody against modified citrullines.

Results

All MMP-9 and MMP-2 proteoforms were identified in archival synovial fluids with the use of zymography analysis and the levels of MMP-9 versus MMP-2 were studied in various arthritic diseases, including rheumatoid arthritis (RA). Secondly, we resolved misinterpretations of MMP-9 levels versus proteolytic activities. Thirdly, a citrullinated, truncated proteoform of MMP-9 was discovered in archival RA synovial fluid samples and its presence was corroborated as citrullinated hemopexin-less MMP-9 in a small prospective RA sample cohort.

Conclusion

Synovial fluids from rheumatoid arthritis contain high levels of MMP-9, including its truncated and citrullinated proteoform. The combination of MMP-9 as analyte and its PTM by citrullination could be of clinical interest, especially in the field of arthritic diseases.

Comparison of efficacy between anti-IL-6 receptor antibody and other biological disease-modifying antirheumatic drugs in the patients with rheumatoid arthritis who have knee joint involvement: the ANSWER cohort, retrospective study

OBJECTIVE

We aimed to investigate the efficacy of anti-IL-6 receptor antibody (aIL-6) and other biologic disease-modifying antirheumatic drugs (bDMARDs), such as TNF inhibitor and CTLA4-Ig in the treatment of rheumatoid arthritis (RA) in patients with knee joint involvement.

METHODS

We retrospectively analyzed 1059 treatment courses of patients with RA who visited our hospitals and were treated with bDMARDs. We categorized them into two groups, with or without knee joint involvement. We investigated the clinical disease activity index (CDAI) at baseline and 12 weeks after the initiation of bDMARDs. We compared the improvement of the markers between aIL-6 and other bDMARDs.

RESULTS

Treatment with aIL-6 significantly increased ΔCDAI (n = 91, 15.4 ± 1.1; mean ± SEM) in patients with knee joint involvement, compared to other bDMARDs (n = 232, 11.0 ± 0.7) at 12 weeks (P = 0.006). Following the multivariate analysis adjusted by the CDAI levels at baseline, age, gender, concomitant use of methotrexate, and the first use of bDMARDs, ΔCDAI levels were significantly higher in aIL-6, compared to other bDMARDs (P = 0.02). However, there was no significant difference in ΔCDAI improvement between aIL-6 (n = 162, 5.9 ± 0.6) and other bDMARDs (n = 573, 6.2 ± 0.4) in patients without swollen knee joints. ΔCDAI levels were equally increased in patients with shoulder and elbow joint involvement.

CONCLUSION

aIL-6 was more effective in the patients with RA and knee joint involvement, compared to other bDMARDs.

Serum matrix metalloproteinase-3 as a noninvasive biomarker of histological synovitis for diagnosis of rheumatoid arthritis

Objective. To explore the correlation between matrix metalloproteinase- (MMP-) 3 and histological synovitis in rheumatoid arthritis (RA). Methods. Serum MMP-3 of 62 patients with active RA was detected by ELISA. Serial synovial tissue sections from all RA patients, 13 osteoarthritis, and 10 orthopedic arthropathies patients were stained with hematoxylin and eosin and immunohistochemically for MMP-3, CD3, CD20, CD38, CD68, and CD15. Results. The percentage of lining MMP3+ cells was significantly higher in RA patients especially with high grade synovitis and it was significantly correlated with Krenn's synovitis score (r = 0.574, P < 0.001) and sublining inflammatory cells. Multivariate stepwise linear regression analysis revealed that the association of the percentage of lining MMP3+ cells with activation of synovial stroma, sublining CD68+ macrophages, and CD15+ neutrophils was stronger than other histological indicators. The percentage of lining MMP3+ cells was significantly correlated with serum MMP-3 in RA (r = 0.656, P < 0.001). Serum MMP-3 was higher in RA patients with high grade synovitis than that of low grade synovitis and significantly correlated with synovitis score and activation of synovial stroma subscore (all P < 0.05). Conclusion. Serum MMP-3 may be an alternative noninvasive biomarker of histological synovitis and RA diagnosis.

Matrix metalloproteinase-3 inhibitor retards treadmill running-induced cartilage degradation in rats

INTRODUCTION

The effect of intra-articular injection of matrix metalloproteinase (MMP)-3 inhibitor was investigated in a rat model to understand the role of MMP-3 in cartilage degradation induced by excessive loading from running.

METHODS

A total of 24 male Wistar rats were randomly assigned into groups of sedentary control (SED), high-intensity running (HIR), HIR + low dosage of MMP-3 Inhibitor I (HIRI1), and HIR + high dosage of MMP-3 Inhibitor I (HIRI2). Rats in the HIR, HIRI1 and HIRI2 groups were intensively trained for six weeks on the treadmill. Those in HIRI1 and HIRI2 groups were provided bilateral intra-articular injections of 80 μL of 0.2 mM and 2 mM MMP-3 Inhibitor I in knee joints once a week, respectively. Blood samples were collected to measure serum MMP-3 level using ELISA. Femoral condyles were collected to observe cartilage characteristics by histochemistry, and MMP-3 as well as collagen II was measured by immunohistochemistry. In addition, cartilage samples were obtained to assess MMP-3 mRNA expression by RT-PCR.

RESULTS

Histological examination showed osteoarthritic changes in rats after six weeks of high intensity running. In comparison to the SED group, significant decreases in glycosaminoglycans (GAG) and collagen content were found in the HIR group, which corresponded to significant increase in serum MMP-3 level, cartilage MMP-3 activity and gene expression. However, such a degradative process was considerably retarded by intra-articular injection of MMP-3 inhibitor at higher dosage. Statistical differences were found between the HIR and HIRI2 groups with regard to GAG and collagen II content, serum MMP-3 level, cartilage MMP-3 activity and gene expression.

CONCLUSIONS

High-intensity running for six weeks may lead to cartilage degradation in a rat model. It was shown that the chrondroprotective effect was offered by the use of intra-articular injection of MMP-3 inhibitor. MMP-3 acts as the key mediator of this catabolic change under such mechanical condition. The results also showed that MMP-3 selective inhibitor may be an effective option for retarding such osteoarthritic changes.

Synovial proinflammatory cytokines and their correlation with matrix metalloproteinase-3 expression in Behçet's disease. Does interleukin-1beta play a major role in Behçet's synovitis?

The objective of this study has been the well established fact that proinflammatory cytokines and metalloproteinases play a crucial role in the pathogenesis of chronic arthritis as well as the development of pannus, with the eventual erosive changes. Among the proinflammatory cytokines, interleukin-18 (IL-18) has been shown to contribute to the pathogenesis of chronic synovitis by increasing the secretion of interleukin-1beta (IL-1beta) and the tumor necrosis factor-alpha (TNF-alpha) and also stimulating angiogenesis. The aim of this study is to investigate the synovial IL-18, IL-1beta, TNF-alpha and matrix metalloproteinase-3 (MMP-3) levels in patients with Behçet's disease (BD), and compare them with the levels of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). 30 patients with BD, 20 with RA, and 20 with OA were included in the study. The synovial levels of IL-18, IL-1beta, TNF-alpha and MMP-3 were detected using the two-step sandwich ELISA method. The synovial IL-18, TNF-alpha and MMP-3 levels were significantly higher in RA patients than patients with BD (P=0.004, 0.019, 0.025, respectively) and with OA (P=0.004, 0.045, 0.032, respectively). There were no differences, with respect to the cytokine levels, when patients with BD were compared with those with OA. Patients with RA and BD had higher IL-1beta levels than patients with OA (P=0.017, 0.013, respectively). However, no such difference was found for IL-1beta between BD and RA patients. Among patients with RA, positive correlations were found between TNF-alpha and MMP-3 (r=0.683, P=0.001). Our results showed that MMP-3 and proinflammatory cytokines, except IL-1beta, were expressed in relatively small quantities in Behçet's synovitis. Detection of the lower levels of these cytokines and metalloproteinases might explain the non-erosive character of Behçet's arthritis. We suggest that IL-1beta may be involved in the pathogenesis of Behçet's synovitis.

Measurement of inflammatory biomarkers in synovial tissue extracts by enzyme-linked immunosorbent assay

We developed methods for measuring inflammatory biomarkers (cytokines, chemokines, and metalloproteinases) in synovial biopsy specimens from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Soluble extracts of synovial fragments were prepared with mild detergent and analyzed by enzyme-linked immunosorbent assay (ELISA) for interleukin 1beta (IL-1beta), IL-6, IL-8, tumor necrosis factor alpha (TNF-alpha), and matrix metalloproteinase 3. The optimal detergent was 0.1% Igepal CA-630, which interfered minimally with ELISA detection but extracted 80% of IL-6 from synovial tissue. Upon spiking, 81 to 107% of added biomarkers could be recovered. To determine within-tissue variability, multiple biopsy specimens from each RA synovial extract were analyzed individually. A resulting coefficient of variation of 35 to 62% indicated that six biopsy specimens per synovial extract would result in a sampling error of < or = 25%. Preliminary power analysis suggested that 8 to 15 patients per group would suffice to observe a threefold difference before and after treatment in a serial biopsy clinical study. The previously described significant differences in IL-1beta, IL-6, IL-8, and TNF-alpha levels between RA and OA could be detected, thereby validating the use of synovial extracts for biomarker analysis in arthritis. These methods allow monitoring of biomarker protein levels in synovial tissue and could potentially be applied to early-phase clinical trials to provide a preliminary estimate of drug efficacy.

Increased matrix metalloproteinase-3 serum levels in rheumatic diseases: relationship with synovitis and steroid treatment

OBJECTIVE

To determine matrix metalloproteinase-3 (MMP-3) serum levels in patients with rheumatic diseases and to study the relation between MMP-3 and C reactive protein (CRP) levels.

METHODS

MMP-3 serum levels were determined by enzyme linked immunosorbent assay (ELISA) in (a) patients with active inflammatory rheumatic diseases: rheumatoid arthritis (RA), psoriatic arthritis, polymyalgia rheumatica, acute crystal arthritis, and ankylosing spondylitis; (b) patients with active inflammatory systemic diseases: cutaneo-articular or renal systemic lupus erythematosus (SLE), systemic sclerosis, and vasculitides; (c) patients with non-inflammatory rheumatic diseases: osteoarthritis and fibromyalgia; (d) critically ill patients without rheumatic diseases, representing an acute inflammatory control group; (e) healthy controls.

RESULTS

MMP-3 serum levels were significantly increased in patients with active RA, psoriatic arthritis, and polymyalgia rheumatica, whether treated or not by corticosteroids, and in female patients with acute crystal arthritis. MMP-3 serum levels were normal in steroid-free patients with active cutaneo-articular or renal SLE, systemic sclerosis, and vasculitides but were significantly increased in steroid treated patients. MMP-3 levels were normal in fibromyalgia, osteoarthritis, ankylosing spondylitis, and acute inflammatory controls. MMP-3 was significantly correlated with CRP in RA (r=0.5, p=0.0004) but not in any of the other disease groups.

CONCLUSIONS

MMP-3 serum levels are increased in inflammatory rheumatic diseases characterised by joint synovitis, such as RA, polymyalgia rheumatica, psoriatic arthritis, and acute crystal arthritis-that is, whether the diseases are acute or chronic, erosive or not. They are normal in SLE, systemic sclerosis, and vasculitides as well as in non-rheumatic inflammatory controls, but are significantly increased by steroids. These data strongly suggest that serum MMP-3 reflects synovial inflammation.

Increased serum proMMP-3 in inflammatory arthritides: a potential indicator of synovial inflammatory monokine activity

OBJECTIVE

To investigate if the increased concentrations of stromelysin (MMP-3) found in the synovial fluid (SF) of patients with various arthritides reflect the concentrations in the circulation.

METHODS

Using a double antibody ELISA, we have measured proMMP-3 concentrations in sera from these patient groups and in others with a heightened acute phase response (APR) as a result of multiple organ failure.

RESULTS

The median serum concentration of proMMP-3 was increased by up to ninefold in the inflammatory arthritides, but not in osteoarthritis or in patients with a heightened APR resulting from a non-chronic inflammatory condition.

CONCLUSION

In chronic inflammatory diseases such as rheumatoid arthritis, serum proMMP-3 may prove to be a more specific indicator of monokine activity than currently available serum markers.