p53 expression in rheumatoid and psoriatic arthritis synovial tissue and association with joint damage

Preoperative Synovial Tissue and Synovial Fluid Biomarkers as Predictors for Outcomes After Knee Arthroscopy and ACL Reconstruction: A Narrative Review

Background

Biomarkers collected in synovial tissue and fluid have been identified as potential predictors of outcomes after arthroscopy.

Purpose

To provide a narrative review of the current literature that assesses the associations between preoperative biomarkers in the synovial fluid or synovial tissue and patient outcomes after knee arthroscopy.

Study Design

Narrative review.

Methods

We searched the PubMed database with keywords, "biomarkers AND arthroscopy," "biomarkers AND anterior cruciate ligament reconstruction," and "biomarkers AND meniscectomy." To be included, studies must have collected synovial fluid or synovial tissue from patients before or during arthroscopic knee surgery and analyzed the relationship of biomarkers to postoperative patient outcomes. Biomarkers were classified into 4 main categories: metabolism of aggrecan in cartilage, metabolism of collagen in cartilage (type II collagen), noncollagenous proteins in the knee, and other. When biomarker levels and outcomes were expressed with continuous variables, we abstracted the Pearson or Spearman correlation coefficients as the effect measure. If the biomarker values were continuous and the outcomes binary, we abstracted the mean or median biomarker values in those with favorable versus unfavorable outcomes. We calculated effect sizes as the difference between means of both groups divided by the standard deviation from the mean in the group with better outcomes.

Results

Eight studies were included in the review. Each study reported different patient outcomes. Biomarkers associated with metabolism of aggrecan, type II collagen metabolism, and noncollagenous proteins as well as inflammatory biomarkers had statistically significant associations with a range of patient outcomes after knee arthroscopy. Difference across studies in sample size and outcome measures precluded choosing a single biomarker that best predicted patient outcomes.

Conclusion

The findings suggest that biomarkers associated with metabolism of aggrecan, type II collagen metabolism, noncollagenous proteins, as well as inflammatory biomarkers may help surgeons and their patients anticipate surgical outcomes.

Identification of immunological characteristics and cuproptosis-related molecular clusters in Rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterised by progressive articular damage, functional loss, and comorbidities. The relationship between cuproptosis, a form of programmed cell death, and RA remains unknown. Therefore, this study aimed to explore cuproptosis-related molecular clusters in RA.

METHODS

Gene expression profiles of GSE93272 were downloaded from the Gene Expression Omnibus to identify the expression profiles of cuproptosis regulators and the immune infiltration characteristics of RA. The molecular clusters of cuproptosis-related genes and the related immune cell infiltration were explored. Cluster-specific differentially expressed genes were identified using the weighted gene co-expression network analysis. Further, an external dataset (GSE15573) was used, and an enzyme-linked immunosorbent assay was performed to validate the predictive efficiency.

RESULTS

Thirteen cuproptosis-related genes and activated immune responses were identified between patients with RA and controls. Immune infiltration revealed significant immunological heterogeneity in the two cuproptosis-related molecular clusters in RA. Functional enrichment indicated that Cluster1 and Cluster2 were predominantly enriched in the toll-like receptor signalling pathway and regulation of autophagy, respectively. Further, the performance of FAM96A and CGRRF1 genes in the external validation dataset was observed to be relatively satisfactory (area under the receiver operating characteristic curve = 0.687 and 0.674, respectively). Based on our serum samples, FAM96A and CGRRF1 both exhibited higher expression levels in patients with RA (p = 0.001; p = 0.000).

CONCLUSIONS

Our study systematically illustrated the involvement of cuproptosis in the progression of RA, and explored the pathogenic mechanisms and novel therapeutic strategies for RA, targeting FAM96A and CGRRF1.

Targeting cyclin-dependent kinases in rheumatoid arthritis and psoriasis - a review of current evidence

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with synovial proliferation and bone erosion, which leads to the structural and functional impairment of the joints. Immune cells, together with synoviocytes, induce a pro-inflammatory environment and novel treatment agents target inflammatory cytokines. Psoriasis is a chronic immune-mediated skin disease, and several cytokines are considered as typical mediators in the progression of the disease, including IL-23, IL-22, and IL-17, among others.

AREA COVERED

In this review, we try to evaluate whether cyclin-dependent kinases (CDK), enzymes that regulate cell cycle and transcription of various genes, could become novel therapeutic targets in RA and psoriasis. We present the main results of in vitro and in vivo studies, as well as scarce clinical reports.

EXPERT OPINION

CDK inhibitors seem promising for treating RA and psoriasis because of their multidirectional effects. CDK inhibitors may affect not only the process of osteoclastogenesis, thereby reducing joint destruction in RA, but also the process of apoptosis of neutrophils and macrophages responsible for the development of inflammation in both RA and psoriasis. However, assessing the efficacy of these drugs in clinical practice requires multi-center, long-term clinical trials evaluating the effectiveness and safety of CDK-blocking therapy in RA and psoriasis.

Psoriatic Arthritis: Pathogenesis and Targeted Therapies

Psoriatic arthritis (PsA), a heterogeneous chronic inflammatory immune-mediated disease characterized by musculoskeletal inflammation (arthritis, enthesitis, spondylitis, and dactylitis), generally occurs in patients with psoriasis. PsA is also associated with uveitis and inflammatory bowel disease (Crohn's disease and ulcerative colitis). To capture these manifestations as well as the associated comorbidities, and to recognize their underlining common pathogenesis, the name of psoriatic disease was coined. The pathogenesis of PsA is complex and multifaceted, with an interplay of genetic predisposition, triggering environmental factors, and activation of the innate and adaptive immune system, although autoinflammation has also been implicated. Research has identified several immune-inflammatory pathways defined by cytokines (IL-23/IL-17, TNF), leading to the development of efficacious therapeutic targets. However, heterogeneous responses to these drugs occur in different patients and in the different tissues involved, resulting in a challenge to the global management of the disease. Therefore, more translational research is necessary in order to identify new targets and improve current disease outcomes. Hopefully, this may become a reality through the integration of different omics technologies that allow better understanding of the relevant cellular and molecular players of the different tissues and manifestations of the disease. In this narrative review, we aim to provide an updated overview of the pathophysiology, including the latest findings from multiomics studies, and to describe current targeted therapies.

Histopathology of Psoriatic Arthritis Synovium—A Narrative Review

Psoriatic arthritis (PsA) is a phenotypically heterogeneous chronic inflammatory disease associated to type I major histocompatibility complex alleles whose complex pathogenesis is still not completely understood. The psoriatic synovium shares general features of chronic inflammation with rheumatoid arthritis (RA) and other arthritis, such as hyperplasia of the intimal lining layer, sublining influx of inflammatory cells and neoangiogenesis, but recognizing disease-specific histopathologic findings may help in diagnosis and definition of therapeutic targets. Available literature reports conflicting data regarding the extension of lining hyperplasia, that does not allow depiction from RA. Sublining inflammatory cells consist of T and B cells and macrophages, plasma cells, mast cells and follicular dendritic cells, with a higher amount of overall T, mast cell and IL-17 producing CD8+ T lymphocytes and lower proportion of plasma cells when compared to the rheumatoid synovium. The amount of synovium IL17+ CD8+ T cells correlates positively to measures of disease activity. Lymphoid follicles with characteristics of germinal centers have been identified, similar to the ones described in RA. Neoangiogenesis is more prominent in PsA but can also be an outstanding feature in some RA samples, and different molecules involved in the process appear to have different influence in each disease. IL-17 and IL-22 expression in the synovium does not allow depiction between diseases. Among other cytokines and molecules likely implicated in disease physiopathology, only IL-35 is demonstrated to be reduced in PsA when compared to RA.

Will rheumatologists ever pick up the arthroscope again?

Conditions prompting physicians and surgeons first adapting endoscopes to peer into joints were mainly the sort of synovial conditions that would concern today's rheumatologists. Rheumatologists were among the pre-World War II pioneers developing and documenting arthroscopy. The post-War father of modern arthroscopy, Watanabe, found rheumatologists among his early students, who took back the technique to their home countries, teaching orthopedists and rheumatologists alike. Rheumatologists described and analyzed the intra-articular features of their common diseases in the '60s and '70s. A groundswell of interest from academic rheumatologists in adapting arthroscopy grew considerably in the '90s with development of "needle scopes" that could be used in an office setting. Rheumatologists helped conduct the very trials the findings of which reduced demand for their arthroscopic services by questioning the efficacy of arthroscopic debridement in osteoarthritis (OA) and also developing biological compounds that greatly reduced the call for any resective intervention in inflammatory arthropathies. The arthroscope has proven an excellent tool for viewing and sampling synovium and continues to serve this purpose at several international research centers. While cartilage is now imaged mainly by magnetic resonance imaging, some OA features - such as a high prevalence of visible calcinosis - beg further arthroscopy-directed investigation. A new generation of "needle scopes" with far superior optics awaits future investigators, should they develop interest.

The p53 status in rheumatoid arthritis with focus on fibroblast-like synoviocytes

P53 is a transcription factor that regulates many signaling pathways like apoptosis, cell cycle, DNA repair, and cellular stress responses. P53 is involved in inflammatory responses through the regulation of inflammatory signaling pathways, induction of cytokines, and matrix metalloproteinase expression. Also, p53 regulates immune responses through modulating Toll-like receptors expression and innate and adaptive immune cell differentiation and maturation. P53 is a modulator of the apoptosis and proliferation processes through regulating multiple anti and pro-apoptotic genes. Rheumatoid arthritis (RA) is categorized as an invasive inflammatory autoimmune disease with irreversible deformity of joints and bone resorption. Different immune and non-immune cells contribute to RA pathogenesis. Fibroblast-like synoviocytes (FLSs) have been recently introduced as a key player in the pathogenesis of RA. These cells in RA synovium produce inflammatory cytokines and matrix metalloproteinases which results in synovitis and joint destruction. Besides, hyper proliferation and apoptosis resistance of FLSs lead to synovial hyperplasia and bone and cartilage destruction. Given the critical role of p53 in inflammation, apoptosis, and cell proliferation, lack of p53 function (due to mutation or low expression) exerts a prominent role for this gene in the pathogenesis of RA. This review focuses on the role of p53 in different mechanisms and cells (specially FLSs) that involved in RA pathogenesis.

GM-CSF Expression and Macrophage Polarization in Joints of Undifferentiated Arthritis Patients Evolving to Rheumatoid Arthritis or Psoriatic Arthritis

Background and Aims

GM-CSF-dependent macrophage polarization has been demonstrated in rheumatoid arthritis (RA). Our aim was to seek diagnostic/prognostic biomarkers for undifferentiated arthritis (UA) by analyzing GM-CSF expression and source, macrophage polarization and density in joints of patients with UA evolving to RA or PsA compared with established RA or PsA, respectively.

Methods

Synovial tissue (ST) from patients with UA evolving to RA (UA>RA, n=8), PsA (UA>PsA, n=9), persistent UA (UA, n=16), established RA (n=12) and PsA (n=10), and healthy controls (n=6), were analyzed. Cell source and quantitative expression of GM-CSF and proteins associated with pro-inflammatory (GM-CSF-driven) and anti-inflammatory (M-CSF-driven) macrophage polarization (activin A, TNFα, MMP12, and CD209, respectively) were assessed in ST CD163⁺ macrophages by multicolor immunofluorescence. GM-CSF and activin A levels were also quantified in paired synovial fluid samples. CD163⁺ macrophage density was determined in all groups by immunofluorescence.

Results

Synovial stromal cells (FAP⁺ CD90⁺ fibroblast, CD90⁺ endothelial cells) and CD163⁺ sublining macrophages were the sources of GM-CSF. ST CD163⁺ macrophages from all groups expressed pro-inflammatory polarization markers (activin A, TNFα, and MMP12). Expression of the M-CSF-dependent anti-inflammatory marker CD209 identified two macrophage subsets (CD163⁺ CD209^high and CD163⁺ CD209^low/-). CD209⁺ macrophages were more abundant in ST from healthy controls and PsA patients, although both macrophage subtypes showed similar levels of pro-inflammatory markers in all groups. In paired synovial fluid samples, activin A was detected in all patients, with higher levels in UA>RA and RA, while GM-CSF was infrequently detected. ST CD163⁺ macrophage density was comparable between UA>RA and UA>PsA patients, but significantly higher than in persistent UA.

Conclusions

GM-CSF is highly expressed by sublining CD90⁺ FAP⁺ synovial fibroblasts, CD90⁺ activated endothelium and CD163⁺ macrophages in different types of arthritis. The polarization state of ST macrophages was similar in all UA and established arthritis groups, with a predominance of pro-inflammatory GM-CSF-associated markers. CD163⁺ macrophage density was significantly higher in the UA phases of RA and PsA compared with persistent UA. Taken together, our findings support the idea that GM-CSF is a strong driver of macrophage polarization and a potential therapeutic target not only in RA but also in PsA and all types of UA.

Differential synovial tissue biomarkers among psoriatic arthritis and rheumatoid factor/anti-citrulline antibody-negative rheumatoid arthritis

Background

Differential diagnosis among psoriatic arthritis (PsA) and seronegative rheumatoid arthritis (Ab^neg RA) can be challenging particularly in the clinical setting of peripheral phenotype and autoantibodies seronegativity. The aim of the study was to identify synovial tissue (ST) biomarkers differentially expressed in PsA and Ab^neg RA and test their predictive value of therapeutic response.

Methods

Thirty-four PsA patients [12 DMARD naive and 22 non-responder to methotrexate (MTX-IR)] with peripheral joint involvement and 55 Ab^neg RA (27 DMARD naive and 28 MTX-IR) underwent US-guided ST biopsy and immunohistochemistry (IHC) for CD68⁺, CD3⁺, CD20⁺, CD21⁺, CD117⁺, and CD138⁺ cells. After study entry, each DMARD-naive patient started MTX therapy and was followed in an outpatient setting for at least 6 months to define the achievement of Minimal Disease Activity (PsA) and DAS remission (Ab^neg RA) status respectively. Each IR-MTX patient was treated according to EULAR recommendations.

Results

At study entry, IHC analysis revealed that PsA patients had comparable levels of lining and sublining CD68⁺ and sublining CD21⁺, CD20⁺, and CD3⁺ cells than Ab^neg RA, despite the therapeutic regimen. Moreover, regardless of the therapeutic scheme, PsA patients showed higher IHC score of CD117⁺ cells (p = 0.0004 and p = 0.0005 for naive and MTX-IR patients respectively) compared to Ab^neg RA patients. Conversely, Ab^neg RA patients showed higher IHC score of CD138⁺ cells, irrespective to the therapeutic scheme (p = 0.04 and p = 0.002 for naive and MTX-IR patients respectively). Analyzing the response rate to the therapeutic scheme, naive PsA patients reaching MDA status at 6 months follow-up, showed, at the study entry, lower IHC score of CD3⁺ cells compared to PsA patients not reaching this outcome (p = 0.02); conversely, naive Ab^neg RA patients reaching DAS remission status at 6 months follow-up, showed, at the study entry, lower IHC score of sublining CD68⁺ cells compared to Ab^neg RA patients not reaching this outcome (p < 0.001).

Conclusions

CD117⁺ and CD138⁺ cells are differentially distributed among PsA and Ab^neg RA. Histological analysis of ST may help to solve the clinical overlap between the two diseases and provides prognostic data about the therapy success.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1898-7) contains supplementary material, which is available to authorized users.

Psoriatic Synovitis: Singularity and Potential Clinical Implications

Psoriatic arthritis (PsA) is an immuno-inflammatory disease with a heterogeneous clinical presentation as affects musculoskeletal tissues (arthritis, enthesitis, spondylitis), skin (psoriasis) and, less frequently, eye (uveitis) and bowel (inflammatory bowel disease). It has been suggested that distinct affected tissues could exhibit different immune-inflammatory pathways so complicating the understanding of the physiopathology of psoriatic disease as well as its treatment. Despite of the key pathogenic and clinical relevance that enthesitis has in PsA, peripheral arthritis is more easily perceived. At the macroscopic level, PsA synovitis has predominantly tortuous, bushy vessels, whereas rheumatoid arthritis (RA) is characterized by mainly straight, branching vessels so reflecting prominent neo-angiogenesis in PsA. Synovial biopsies have demonstrated a similar cellular and molecular picture in PsA and RA, although some differences have been reported at the group level, as higher density of vessels, CD163+ macrophages, neutrophils and mast cells in PsA. In fact, synovial IL-17+ mast cells are significantly increased in PsA and produce more IL-17A compared with RA, and a proof of concept study supports its relevant role in the synovitis of SpA, included PsA. As firstly reported in RA, synovial lymphoid neogenesis is found also in the same proportion of PsA as in RA patients, despite the lack of autoantibodies in PsA. These lymphoid structures are associated with activation of the IL-23/Th17 pathway in RA and seemly in PsA, which could be useful to stratify RA patients. Immunohistochemical and transcriptomic methodologies have still not found synovial biomarkers useful to distinguish psoriatic from rheumatoid synovitis at the patient level. However, modern methodologies, as MALDI-Mass Spectrometry Imaging, applied to the study of synovial tissue have revealed metabolic and lipid signatures which could support clinical decision-making in the diagnosis of PsA and RA and to go further toward the personalized medicine.

1, 25-dihydroxy-vitamin D3 with tumor necrosis factor-alpha protects against rheumatoid arthritis by promoting p53 acetylation-mediated apoptosis via Sirt1 in synoviocytes

Impaired apoptosis of fibroblast-like synoviocytes (FLSs) causes synovial hyperplasia, facilitating destruction of cartilage and bone in rheumatoid arthritis (RA). Tumor necrosis factor (TNF)-α, a dominant inflammatory mediator in RA pathogenesis, promotes progression of RA symptoms. Prevalence of 1, 25-dihydroxy-vitamin D₃ (hereafter termed VD) deficiency is 30-63% in patients with RA. Whether VD leads to apoptosis or enhances TNF-α-mediated apoptosis in FLSs to ameliorate RA is unclear. To determine this, 10-week-old CYP27B1-deficient (CYP27B1^-/-) mice with collagen-induced arthritis (CIA) were intraperitoneally treated with 1 μg/kg VD every other day for 9 weeks. RA phenotypes were compared between vehicle-treated CYP27B1^-/- and wild-type CIA mice. Human rheumatoid FLS-MH7A cells were treated with Dulbecco's modified Eagle's medium (DMEM) without fetal bovine serum (FBS) for 24 h, then with different concentrations of VD and TNF-α, human vitamin D receptor (VDR) siRNA or the p53 pro-apoptotic inhibitor pifithrin-α. Apoptosis and p53 pro-apoptotic signaling were analyzed. The 19-week-old vehicle-treated CYP27B1^-/- CIA mice had increased cumulative arthritis scores and levels of serous rheumatoid factors and C-reactive protein. They had exacerbated articular cartilage and bone destruction, joint space narrowing, joint stiffness, deformity and dysfunction, synovitis and TNF-α secretion, FLS hyperplasia with increased proliferation and decreased apoptosis compared to CIA mice. These RA phenotypes that were aggravated in CIA mice by CYP27B1 deficiency were largely rescued by VD treatment. In vitro, VD with TNF-α treatment upregulated p53 acetylation-mediated apoptosis in MH7A cells by promoting Sirt1 translocation from the nucleus to the cytoplasm. These findings indicated that VD with TNF-α protected against RA by promoting apoptosis of FLSs. The results indicated that clinical administration of VD could be a specific therapy to promote FLS apoptosis and prevent RA progression.

Immunopathology of synovitis: from histology to molecular pathways

Increased knowledge about pathological processes active in inflammatory joint diseases is needed to initiate personalized medicine based on targeted treatments in the future. The molecular and cellular pathways that are active during joint inflammation may differ between the various inflammatory joint diseases, between different patient subgroups within one disease, or even between different stages of the disease in a single patient. In this review, we evaluate synovial inflammation in terms of descriptive histopathology through to more functional studies on human synovial tissue inflammation in RA and SpA, in phenotypic subgroups of RA and SpA patients, and during the disease course of both diseases.

Differential co-expression analysis of rheumatoid arthritis with microarray data

The aim of the present study was to investigate the underlying molecular mechanisms of rheumatoid arthritis (RA) using microarray expression profiles from osteoarthritis and RA patients, to improve diagnosis and treatment strategies for the condition. The gene expression profile of GSE27390 was downloaded from Gene Expression Omnibus, including 19 samples from patients with RA (n=9) or osteoarthritis (n=10). Firstly, the differentially expressed genes (DEGs) were obtained with the thresholds of |logFC|>1.0 and P<0.05, using the t‑test method in LIMMA package. Then, differentially co-expressed genes (DCGs) and differentially co-expressed links (DCLs) were screened with q<0.25 by the differential coexpression analysis and differential regulation analysis of gene expression microarray data package. Secondly, pathway enrichment analysis for DCGs was performed by the Database for Annotation, Visualization and Integrated Discovery and the DCLs associated with RA were selected by comparing the obtained DCLs with known transcription factor (TF)-targets in the TRANSFAC database. Finally, the obtained TFs were mapped to the known TF-targets to construct the network using cytoscape software. A total of 1755 DEGs, 457 DCGs and 101988 DCLs were achieved and there were 20 TFs in the obtained six TF-target relations (STAT3-TNF, PBX1‑PLAU, SOCS3-STAT3, GATA1-ETS2, ETS1-ICAM4 and CEBPE‑GATA1) and 457 DCGs. A number of TF-target relations in the constructed network were not within DCLs when the TF and target gene were DCGs. The identified TFs may have an important role in the pathogenesis of RA and have the potential to be used as biomarkers for the development of novel diagnostic and therapeutic strategies for RA.

Light and electron microscopic features of synovium in patients with psoriatic arthritis

INTRODUCTION

Few ultrastructural studies have been reported in psoriatic arthritis (PsA). The authors report a series of synovial biopsies with emphasis on patients with early disease to look for distinctive light (LM) and electron microscopic (EM) features of possible importance.

METHODS

The authors examined synovial biopsies obtained primarily by needle biopsy from 13 PsA patients using LM and/or EM. Sections from 12 patients were evaluated by LM for vascularity, synovial lining thickness, fibrin deposition, and inflammation via a semi-quantitative scale. Nine EM specimens were descriptively analyzed. Clinical, synovial fluid (SF), and radiographic characteristics were recorded.

RESULTS

Patients were mostly male, with mean disease duration before biopsy of 2.19 ± 2.60 years; 7 patients had arthritis for less than 1 year. All patients had peripheral arthritis, 2 had axial involvement. SFs disclosed predominance of polymorphonuclear leukocytes. LM demonstrated proliferation of synovial lining cells, lymphocyte and plasma cell infiltration, as well as dramatic clusters of small vessels in the superficial synovium. EMs showed more detailed vascular changes, including small, subendothelial, electron-dense deposits and scattered microparticles in vessel lumens and walls.

CONCLUSIONS

Prominent vascularity is confirmed as an important feature of some PsA. Vascular changes and other features, including the first EM demonstration of microparticles in PsA (identified as potent factors in other inflammatory joint diseases), are potential targets for therapy.

Synovitis in psoriatic arthritis: immunohistochemistry, comparisons with rheumatoid arthritis, and effects of therapy

Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy associated with psoriasis that affects the peripheral joints, spine, and entheses. Most patients with PsA present with peripheral synovitis of the oligoarticular or polyarticular subtype. As one of the targets of this disease, studies on the synovium may provide insight into the mechanisms involved in this condition. Key findings from the available studies comparing synovial tissue of PsA and rheumatoid arthritis patients are discussed in this review. Also, changes in the synovial infiltrate, expression of proinflammatory cytokines and adhesion molecules, and vascularity in synovial tissue after treatment with various medications are addressed. Finally, a model for proof-of-principle study design using serial synovial biopsies is described, which could be used to predict clinical (in)efficacy in early clinical trial design in PsA.

Effect of Wenhua Juanbi recipe on proliferation and apoptosis of synoviocytes in rats with collagen-inducing arthritis

OBJECTIVE

To study the effect of Wenhua Juanbi Recipe (WJR) on proliferation and apoptosis of synoviocytes in rats with collagen-inducing arthritis (CIA).

METHODS

A CIA model was induced by intradermal injection of bovine collagen type II emulsion at the base of rat tails. Thirty modeled healthy Wistar rats were randomly assigned to one of three groups (10 per group): the model group, the methotrexate (MTX)-treated group (0.78 mg/kg) and the WJR-treated group (22.9 g/kg). A group of 10 healthy rats was used as normal control. Treatments or normal saline for the control group were administered by oral gavage once daily. Rats were sacrificed after 30-day treatment and subjected to the following examinations: arthritis index (AI) was estimated, inflammatory cell infiltration and proliferation in synovial membrane were evaluated by microscopy, the synoviocyte apoptosis was determined by TUNEL assay, and the cell apoptosis index was calculated.

RESULTS

AI was lowered significantly in the WJR group compared to the model group (P<0.01). The pathological findings observed in the model group were reversed in the WJR group, including increase in inflammatory cell infiltration and synoviocyte proliferation in synovial membrane and reduction in cell apoptosis index (all P<0.01).

CONCLUSIONS

Synoviocyte proliferation and apoptosis reduction were present in CIA rats. WJR was effective in treating the rat model of CIA. The therapeutic effect might be exerted through inducing apoptosis and suppressing proliferation of synoviocytes.

Genotoxicity of anti-tumor necrosis factor therapy in patients with juvenile idiopathic arthritis

OBJECTIVE

To assess the possible effects of both inflammation and the anti-tumor necrosis factor agents (anti-TNF) on DNA damage with a specific assay, and their effects on the repair capacity of DNA.

METHODS

From a group of 20 children with juvenile idiopathic arthritis (JIA), 16 patients who completed the study and 16 control subjects were evaluated. DNA damage and repair capacity were analyzed by the comet assay at the level of peripheral lymphocytes before anti-TNF (etanercept) injections and on the 15th, 90th, and 180th days after the first injection.

RESULTS

The amount of damage as detected by the aforementioned assay was higher in patients with JIA compared with controls. On the 15th day after the initial anti-TNF injection, there was a decrease in the mean DNA tail length of JIA patients, however on the 90th day an increase was observed; thereafter, an upward trend was observed until the end of the study. JIA patients had a DNA repair capacity that was significantly less than that of controls.

CONCLUSION

The results of the comet technique suggests that JIA patients already have increased basal DNA damage before anti-TNF therapy; they are more sensitive to the DNA damage produced by H(2)O(2), and have a less efficient DNA repair system in comparison with control cells. After an initial improvement at 2 weeks, parameters of genotoxicity worsened, and DNA repair was further impaired 6 months after the addition of an anti-TNF agent to treatment.

Amelioration of experimental arthritis by a telomerase-dependent conditionally replicating adenovirus that targets synovial fibroblasts

OBJECTIVE

Synovial fibroblasts (SFs) play a pivotal role in the pathogenesis of rheumatoid arthritis (RA). It has been documented that the phenotype of rheumatoid synovium is similar, in many respects, to that of an aggressive tumor. In this study, a novel, genetically engineered adenovirus was designed to lyse SFs that exhibit high telomerase activity and p53 mutations, and its effects as a novel therapeutic strategy were assessed in an experimental arthritis model.

METHODS

An E1B-55-kd-deleted adenovirus driven by the human telomerase reverse transcriptase promoter was constructed (designated Ad.GS1). Cytolysis of SFs and productive replication of Ad.GS1 in the SFs of rats with collagen-induced arthritis (CIA), as well as the SFs of patients with RA (RASFs), were assessed in vitro and in vivo. Treatment responses, as well as the presence of disease-related cytokines and enzymes in the ankle joints, were determined in the murine model.

RESULTS

Ad.GS1 replicated in and induced cytolysis of human RASFs and SFs from arthritic rats, but spared normal fibroblasts. Bioluminescence imaging in vivo also demonstrated replication of Ad.GS1 in arthritic rat joints, but not in normal rat joints. Intraarticular administration of Ad.GS1 significantly reduced the ankle circumference, articular index scores, radiographic scores, and histologic scores and decreased the production of interleukin-1beta, matrix metalloproteinase 9, and prolyl 4-hydroxylase in rats with CIA compared with their control counterparts.

CONCLUSION

This study is the first to demonstrate the amelioration of arthritic symptoms by a novel, telomerase-dependent adenovirus in the rat CIA model, an experimental model that resembles human RA. In addition, the results suggest that because of its ability to induce cytolysis of SFs, this virus may be further explored as a therapeutic agent in patients with RA.

Analyses of differential proteome of human synovial fibroblasts obtained from arthritis

There is mounting evidence indicating that the synovial fibroblasts (SFs) contribute to the pathogenesis of rheumatoid arthritis (RA). The present study showed the differential proteins expression pattern of SFs from patients with RA or osteoarthritis (OA) and healthy control. Cellular proteins of cultured SFs were subjected to 2-DE and visualized by silver nitrate staining. A total of 49 spots that were statistically and differentially overexpressed in RA or OA in comparison to healthy ones were identified by MALDI-TOF-MS, and 25 proteins were successfully identified. Western blot was used to further verify some of the differential proteins. These proteins included enzymatic and structural proteins, signal transduction proteins, calcium binding protein, etc. From all of the identified proteins, a number of proteins have been implicated that involved in the healthy or pathological SFs function (e.g., S100A4, S100A10, cathepsin D) or that have potential diagnostic and prognostic value for RA (alpha-enolase and TPI) or that may be the new therapeutic targets (Annexin, SOD, PRX).

Psoriatic disease--from skin to bone

Psoriatic arthritis is an inflammatory joint disease that is heterogeneous in presentation and clinical course. Evidence that this disease is distinct from rheumatoid arthritis and other spondyloarthropathies is based on data derived from characteristic clinical features, histopathologic analyses, immunogenetic associations and musculoskeletal imaging. Emphasis has centered previously on a dominant role for the T lymphocyte in the inflammatory process; however, studies provide support for a major contribution from monocyte-macrophages in the initiation and perpetuation of joint and skin inflammation. The occurrence of arthritis in the absence of psoriasis in a minority of patients with psoriatic arthritis, coupled with divergent genetic risk factors, indicates that psoriatic arthritis is distinct from psoriatic skin inflammation. A new terminology, psoriatic disease, has emerged that encompasses the various manifestations of tissue and organ involvement observed in many psoriasis patients, including inflammation in the joint, eye and gut. Moreover, adverse cardiovascular and metabolic outcomes in patients with psoriasis or psoriatic arthritis might be directly linked to the cutaneous and musculoskeletal manifestations of these diseases via subsets of circulating monocytes and tissue macrophages activated by inflammatory cytokine networks that arise in the skin and possibly the joint.

Mutation and citrullination modifies vimentin to a novel autoantigen for rheumatoid arthritis

OBJECTIVE

Modification of antigens represents a trigger for the generation of autoantibodies. In the pathogenesis of rheumatoid arthritis (RA), citrullination of proteins has been shown to be a critical process, and the determination of antibodies against citrullinated antigens has been a diagnostic milestone. We undertook this study to determine whether antibodies to mutated and citrullinated vimentin (MCV) could serve as a diagnostic and prognostic marker for RA.

METHODS

We identified novel isoforms of human MCV in the synovial fluid of RA patients. The significance of these disease-related modifications was investigated by the analysis of autoantibody reactivities. In a group of 1,151 RA patients, the diagnostic significance and the prognostic value of an anti-MCV enzyme-linked immunosorbent assay (ELISA) were compared with that of an anti-cyclic citrullinated peptide (anti-CCP) ELISA.

RESULTS

In RA, sensitivities of 82% and 72% were calculated for the anti-MCV and anti-CCP assays, respectively. The specificity of both assays was comparable (98% and 96%, respectively). In followup analyses of 16 RA patients with moderate disease activity (mean Disease Activity Score in 28 joints [DAS28] of 2.72) and 26 RA patients with active disease (mean DAS28 of 5.07), disease stratification of RA was possible using the anti-MCV assay (P = 0.0084). A significant correlation of anti-MCV antibodies with the DAS28 was documented (r = 0.5334, P = 0.0003), in 42 RA patients (n = 427 antibody determinations at different time points).

CONCLUSION

Antigenic properties of vimentin were determined by mutation and citrullination. Anti-MCV antibodies are a novel diagnostic marker for RA. Furthermore, they may allow monitoring and-if confirmed in even larger series of patients-stratification of disease.

Expression of p53 in lesions and unaffected skin of patients with plaque-type and guttate psoriasis: A quantitative comparative study

Psoriasis is a common inflammatory and hyperproliferative skin disease characterized by hyperproliferation of keratinocytes. The pathogenesis of psoriasis has yet to be determined. The control of cell growth is a delicately balanced process, regulated by external signals or the internal genetic program of an individual cell. In psoriasis, these processes are disturbed and some candidate genes like p53 are suspected of being involved in the pathogenesis of the disease. The p53 protein is essential for the regulation of cell proliferation. The study was performed on 32 patients with psoriasis (24 plaque type, eight guttate type). Biopsy specimens for immunohistochemical determination of p53 protein expression were collected from both the lesional and the nonlesional skin sites that were not exposed to sun in all of the patients (n = 32). Taking the ultraviolet (UV) exposure of the skin into consideration, a third skin sample was taken from each patient (n = 7) who had lesions on the sun-exposed areas. Immunohistochemical assessment of p53 expression in skin was determined as p53 protein expression per 1000 cells (keratinocytes). The statistical analysis revealed that the expressions of p53 per 1000 cells were higher in non-sun-exposed lesional skin than the non-sun-exposed nonlesional skin, also in plaque-type psoriasis than guttate-type psoriasis (P = 0.000, P = 0.046, P = 0.037, respectively). There was a positive correlation between the p53 expression in non-sun-exposed lesional skin versus expression in sun-exposed lesional skin (cubic centimeters = 0.811, P = 0.027). Our results show a stronger association of elevated p53 expression with chronic rather than acute inflammatory psoriasis. This may indicate a mechanistic difference between plaque-type and guttate psoriasis. Alternatively, this could reflect a chronological course as the disease transitions from an acute to a chronic phase.

Differential expression of syndecans and glypicans in chronically inflamed synovium

BACKGROUND

Membrane-bound heparan sulphate proteoglycans (HSPGs) act as co-receptors and presenters of cytokines and are involved in cell-matrix and cell-cell adhesion.

AIM

To investigate which HSPGs are expressed in knee joint synovia from patients with different forms of arthritis and normal individuals.

METHODS

Synovial samples were obtained from patients with early rheumatoid arthritis (n = 8), longstanding rheumatoid arthritis (n = 13), psoriatic arthritis (n = 7), osteoarthritis (n = 6) and normal joints (n = 12). Expression of syndecan-1, -2, -3 and -4 and glypican-1, -3 and -4 was analysed by immunohistochemistry and dual label immunofluorescence.

RESULTS

The expression of HSPGs in chronically inflamed synovium exhibited a differential distribution. Syndecan-1 was present in the mononuclear infiltrates of synovia from patients with rheumatoid and psoriatic arthritis where it was expressed by plasma cells. Syndecan-2 was present mainly in blood vessels where it occurred on endothelial cells, pericytes and smooth muscle cells. Syndecan-3 stained intensely in endothelial cells but also occurred in sublining macrophages and the lining layer. Glypican-4 occurred in the lining layer and blood vessels. Increased expression of these HSPGs was apparent in rheumatoid and psoriatic compared to osteoarthritic and normal synovia. Little or no staining for syndecan-4, glypican-1 and glypican-3 was seen in all samples.

DISCUSSION

Selected HSPGs, such as syndecan-1, -2 and -3 and glypican-4, could play a part in the pathophysiology of arthritis, such as the migration and retention of leukocytes and angiogenesis in the chronically inflamed synovium.

Ectopic lymphoid neogenesis in psoriatic arthritis

BACKGROUND

Ectopic lymphoid neogenesis (LN) occurs in rheumatoid synovium, where it is thought to drive local antigen-dependent B cell development and autoantibody production. This process involves the expression of specific homing chemokines and the development of high endothelial venules (HEV).

OBJECTIVE

To investigate whether these mechanisms occur in psoriatic arthritis (PsA) synovium, where autoantibodies have not been described and the organisation and function of B cells is not clear, and to analyse their clinical correlates.

METHODS

Arthroscopic synovial biopsy specimens from patients with PsA before and after tumour necrosis factor alpha blockade were characterised by immunohistochemical analysis for T/B cell segregation, peripheral lymph node addressin (PNAd)-positive HEV, and the expression of CXCL13, CCL21 and CXCL12 chemokines in relation to the size of lymphoid aggregates.

RESULTS

Lymphoid aggregates of variable sizes were observed in 25 of 27 PsA synovial tissues. T/B cell segregation was often observed, and was correlated with the size of lymphoid aggregates. A close relationship between the presence of large and highly organised aggregates, the development of PNAd+ HEV, and the expression of CXCL13 and CCL21 was found. Large organised aggregates with all LN features were found in 13 of 27 tissues. LN in PsA synovitis was not related to the duration, pattern or severity of the disease. The synovial LN pattern remained stable over time in persistent synovitis, but a complete response to treatment was associated with a regression of the LN features.

CONCLUSIONS

LN occurs frequently in inflamed PsA synovial tissues. Highly organised follicles display the characteristic features of PNAd+ HEV and CXCL13 and CCL21 expression, demonstrating that the microanatomical bases for germinal centre formation are present in PsA. The regression of LN on effective treatment indicates that the pathogenic and clinical relevance of these structures in PsA merits further investigation.

Detailed analysis of the cell infiltrate and the expression of mediators of synovial inflammation and joint destruction in the synovium of patients with psoriatic arthritis: implications for treatment

BACKGROUND

The synovial tissue is a primary target of many inflammatory arthropathies, including psoriatic arthritis (PsA). Identification of proinflammatory molecules in the synovium may help to identify potentially therapeutic targets.

OBJECTIVE

To investigate extensively the features of cell infiltration and expression of mediators of inflammation and joint destruction in the synovium of patients with PsA compared with patients with rheumatoid arthritis matched for disease duration and use of drugs.

METHODS

Multiple synovial tissue biopsy specimens were obtained by arthroscopy from an inflamed joint in 19 patients with PsA (eight oligoarthritis, 11 polyarthritis) and 24 patients with rheumatoid arthritis. Biopsy specimens were analysed by immunohistochemistry to detect T cells, plasma cells, fibroblast-like synoviocytes, macrophages, proinflammatory cytokines, matrix metalloproteinases and tissue inhibitor metalloproteinase-1, adhesion molecules and vascular markers. Stained sections were evaluated by digital image analysis.

RESULTS

The synovial infiltrate of patients with PsA and rheumatoid arthritis was comparable with regard to numbers of fibroblast-like synoviocytes and macrophages. T cell numbers were considerably lower in the synovium of patients with PsA. The number of plasma cells also tended to be lower in PsA. The expression of tumour necrosis factor alpha (TNFalpha), interleukin (IL) 1beta, IL6 and IL18 was as high in PsA as in rheumatoid arthritis. The expression of matrix metalloproteinases, adhesion molecules and vascular markers was comparable for PsA and rheumatoid arthritis.

CONCLUSION

These data show increased proinflammatory cytokine expression in PsA synovium, comparable to results obtained for rheumatoid arthritis, and support the notion that, in addition to TNFalpha blockade, there may be a rationale for treatments directed at IL1beta, IL6 and IL18.

Synovial vascular patterns and angiogenic factors expression in synovial tissue and serum of patients with rheumatoid arthritis

OBJECTIVE

To determine whether subgroups of rheumatoid arthritis (RA) patients classified according to their synovial vascular pattern have a different expression of angiogenic mediators or exhibit distinct clinical or biological characteristics.

METHODS

Arthroscopies were performed in 27 patients with RA and synovial samples were obtained. Vascular morphology was classified in three patterns: straight (S), tortuous (T) and mixed (M). Immunostaining was performed with anti-vascular endothelial growth factor (anti-VEGF), anti-vascular endothelial growth factor receptor (VEGFR)-1, anti-VEGFR-2, anti-IL-8 and anti-TGF-beta, and measured by digital image analysis. Serum levels of VEGF, TGF-beta and IL-8, and clinical, radiographic and serological data were also analysed.

RESULTS

Eleven (41%) patients had the S pattern, nine (33%) the M pattern and seven (26%) the T pattern. The S and M groups had a higher prevalence of rheumatoid factor positivity and erosive disease, and higher levels of markers of systemic inflammation compared with the T group. Synovial expression of VEGF was higher in the S and T groups compared with the M group, whereas TGF-beta was higher in the T compared with the S and M groups. Distinct synovial distribution of VEGF and TGF-beta between groups was also observed.

CONCLUSIONS

This preliminary study suggests that RA patients with the S and M patterns share different clinical, biological and serological characteristics compared with those with the T pattern, which may constitute a group with less severe disease. Differences in the intensity and distribution of synovial expression of VEGF and TGF-beta observed between groups could have pathophysiological relevance. However, larger, prospective multicentre studies would be need to determine the clinical relevance of vascular patterns in RA.

Association of functional variants of PTPN22 and tp53 in psoriatic arthritis: a case-control study

Recent studies have implicated PTPN22 and tp53 in susceptibility to several autoimmune diseases, including rheumatoid arthritis, suggesting that these genes are important in maintaining immune homeostasis. Because autoimmune diseases may share similar susceptibility loci, investigation of these genes in psoriatic arthritis (PsA) is of potential relevance. As a result we investigated known coding polymorphisms in PTPN22 and tp53 in a homogenous Caucasian PsA cohort from Newfoundland, Canada and an admixed Caucasian PsA cohort from Toronto, Canada. We observed a moderate association of the R620W variant of PTPN22 with PsA in the Toronto population only. Because of the conflicting findings reported regarding the association of PTPN22 with PsA, further studies in other PsA populations are warranted.

Pathogenesis of psoriatic arthritis

PURPOSE OF REVIEW

Heterogeneity in clinical presentation and disease course has hindered understanding of disease mechanisms in psoriatic arthritis, but recent studies have provided insights into pathogenesis. This review examines relevant animal models and genetic factors implicated in disease susceptibility. Also, recent reports on mechanisms related to synovial and entheseal inflammation are discussed.

RECENT FINDINGS

Two transgenic mouse models (amphiregulin, STAT-3) were reported that have features of psoriatic arthritis and psoriasis respectively. Genetic studies did not find associations between psoriatic arthritis and several class I major histocompatibility complex alleles, the caspase-activating recruitment domain 15 domain, or the major histocompatibility complex class I chain-related gene A9 allele, in sharp contrast to previous reports. The striking association of psoriatic arthritis with mutations in the killer immunoglobulin receptors on natural killer cells is particularly exciting but needs further study. Psoriatic arthritis has histopathologic features that are more characteristic of other forms of spondyloarthritis than rheumatoid arthritis. Moreover, several of these features correlate with clinical disease activity. Matrix metalloproteinases are strongly expressed in psoriatic arthritis synovium, and serum matrix metalloproteinases-3 may be a reliable biomarker for monitoring disease response. Finally, the concept of an 'enthesis organ' may explain the magnetic resonance imaging findings and clinical signs of psoriatic enthesitis and dactylitis.

SUMMARY

Recent findings highlight the importance of innate immune mechanisms in disease pathogenesis. Moreover, psoriatic arthritis and rheumatoid arthritis synovium have divergent histopathologic features that indicate distinct disease mechanisms. The generation of appropriate animal models coupled with reliable biomarkers will result in a deeper understanding of disease pathogenesis and will facilitate the identification of new therapeutic targets.

Synovial histopathology of psoriatic arthritis, both oligo- and polyarticular, resembles spondyloarthropathy more than it does rheumatoid arthritis

At present only few biological data are available to indicate whether psoriatic arthritis (PsA) is part of the spondyloarthropathy (SpA) concept, whether it is a separate disease entity or a heterogeneous disease group with oligoarticular/axial forms belonging to SpA and polyarticular forms resembling rheumatoid arthritis (RA). To address this issue with regard to peripheral synovitis, we compared the synovial characteristics of PsA with those of ankylosing spondylitis (AS)/undifferentiated SpA (USpA) and RA, and compared the synovium of oligoarticular versus polyarticular PsA. Synovial biopsies were obtained from patients with RA, nonpsoriatic SpA (AS + USpA), and oligoarticular and polyarticular PsA. The histological analysis included examination(s) of the lining layer thickness, vascularity, cellular infiltration, lymphoid aggregates, plasma cells and neutrophils. Also, we performed immunohistochemical assessments of CD3, CD4, CD8, CD20, CD38, CD138, CD68, CD163, CD83, CD1a, CD146, alphaVbeta3, E-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, S100A12, intracellular citrullinated proteins and major histocompatibility complex (MHC)-human cartilage (HC) gp39 peptide complexes. Comparing SpA (PsA + AS + USpA) with RA, vascularity, and neutrophil and CD163+ macrophage counts were greater in SpA (P < 0.05), whereas lining layer thickness and the number of CD83+ dendritic cells were greater in RA (P < 0.05). In RA, 44% of samples exhibited positive staining for intracellular citrullinated proteins and 46% for MHC-HC gp39 peptide complexes, whereas no staining for these markers was observed in SpA samples. We excluded influences of disease-modifying antirheumatic drug and/or corticosteroid treatment by conducting systematic analyses of treated and untreated subgroups. Focusing on PsA, no significant differences were observed between PsA and nonpsoriatic SpA. In contrast, vascularity (P < 0.001) and neutrophils were increased in PsA as compared with RA (P = 0.010), whereas staining for intracellular citrullinated proteins and MHC-HC gp39 peptide complexes was exclusively observed in RA (both P = 0.001), indicating that the same discriminating features are found in PsA and other SpA subtypes compared with RA. Exploring synovial histopathology between oligoarticular and polyarticular PsA, no significant differences were noted. Moreover, intracellular citrullinated proteins and MHC-HC gp39 peptide complexes, which are specific markers for RA, were observed in neither oligoarticular nor polyarticular PsA. Taken together, these data indicate that the synovial histopathology of PsA, either oligoarticular or polyarticular, resembles that of other SpA subtypes, whereas both groups can be differentiated from RA on the basis of these same synovial features, suggesting that peripheral synovitis in PsA belongs to the SpA concept.