Modulation of angiogenic vascular endothelial growth factor by tumor necrosis factor alpha and interleukin-1 in rheumatoid arthritis

Anti-angiogenic effect of triptolide in rheumatoid arthritis by targeting angiogenic cascade

Rheumatoid arthritis (RA) is characterized by a pre-vascular seriously inflammatory phase, followed by a vascular phase with high increase in vessel growth. Since angiogenesis has been considered as an essential event in perpetuating inflammatory and immune responses, as well as supporting pannus growth and development of RA, inhibition of angiogenesis has been proposed as a novel therapeutic strategy for RA. Triptolide, a diterpenoid triepoxide from Tripterygium wilfordii Hook F, has been extensively used in treatment of RA patients. It also acts as a small molecule inhibitor of tumor angiogenesis in several cancer types. However, it is unclear whether triptolide possesses an anti-angiogenic effect in RA. To address this problem, we constructed collagen-induced arthritis (CIA) model using DA rats by the injection of bovine type II collagen. Then, CIA rats were treated with triptolide (11-45 µg/kg/day) starting on the day 1 after first immunization. The arthritis scores (P<0.05) and the arthritis incidence (P<0.05) of inflamed joints were both significantly decreased in triptolide-treated CIA rats compared to vehicle CIA rats. More interestingly, doses of 11~45 µg/kg triptolide could markedly reduce the capillaries, small, medium and large vessel density in synovial membrane tissues of inflamed joints (all P<0.05). Moreover, triptolide inhibited matrigel-induced cell adhesion of HFLS-RA and HUVEC. It also disrupted tube formation of HUVEC on matrigel and suppressed the VEGF-induced chemotactic migration of HFLS-RA and HUVEC, respectively. Furthermore, triptolide significantly reduced the expression of angiogenic activators including TNF-α, IL-17, VEGF, VEGFR, Ang-1, Ang-2 and Tie2, as well as suppressed the IL1-β-induced phosphorylated of ERK, p38 and JNK at protein levels. In conclusion, our data suggest for the first time that triptolide may possess anti-angiogenic effect in RA both in vivo and in vitro assay systems by downregulating the angiogenic activators and inhibiting the activation of mitogen-activated protein kinase downstream signal pathway.

Wen Luo Yin inhibits angiogenesis in collagen-induced arthritis rat model and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE AND AIM OF THE STUDY

Wen Luo Yin (WLY) is a traditional Chinese formula, which has the traditional use of scattering cold pathogen, draining dampness, freeing the flow of network vessels and relieving pains. It is extensively used in the treatment of rheumatoid arthritis (RA) patients for more than 2000 years, but its actions on angiogenesis of RA have not been clarified. The present study aims to determine the anti-angiogenic activity of WLY on collagen-induced arthritis (CIA) rat model and in human fibroblast-like synoviocytes of RA (HFLS-RA) and human umbilical vein endothelial cells (HUVEC).

MATERIALS AND METHODS

For in vivo experiment, arthritis was induced by immunization with bovine II collagen in DA rats. Treatment with WLY (3.45, 6.9, 13.8 g/kg, p.o., daily), or vehicle began from day 1 to day 28 of first immunization. The arthritis score, arthritis incidence, microfocal computed tomography analysis and histopathology evaluation of inflamed joints were assessed. Angiogenesis was measured by synovial vessel density with immunohistochemistry and histomorphometric analysis in synovial membrane tissues of joints. For in vitro experiments, HFLS-RA and HUVEC were used. Assays to determine HFLS-RA migration and adhesion were performed in the presence of vascular endothelial growth factor (VEGF)165 or interleukin (IL)-1β and/or the WLY (8, 16, 32 mg/ml). Angiogenesis was assessed by measuring the migration, adhesion, and tube formation of HUVEC. Further the effect of treatment with WLY on expression levels of angiogenic activators in sera of CIA rats and in IL-1β-induced HFLS-RA were evaluated by enzyme linked immunosorbent assay.

RESULTS

WLY significantly decreased the arthritis score and arthritis incidence, and inhibited inflammation, pannus formation, cartilage and bone destruction of inflamed joints in CIA rats. More interestingly, doses of 3.45-13.8 g/kg WLY could markedly reduce the capillaries, small, medium and large vessel density in synovial membrane tissues of inflamed joints. Moreover, WLY suppressed the VEGF-induced chemotactic migration of HFLS-RA and HUVEC, and inhibited matrigel-induced cell adhesion of them. It also disrupted tube formation of HUVEC on matrigel. Furthermore, WLY significantly reduced the expression of angiogenic activators including tumor necrosis factor-α, IL-1β, IL-17, VEGF, VEGFR, angiopoietin (Ang)-1, Ang-2 and Ang-2 receptor in sera of CIA rats and/or in IL-1β-induced HFLS-RA/HUVEC.

CONCLUSIONS

Our data suggest for the first time that WLY posses the anti-angiogenic effect in RA both in vivo and in vitro by downregulating angiogenic activators.

The role of IL-33 in rheumatic diseases

Interleukin-33 (IL-33), a novel member of IL-1 family, has been recently implicated in several inflammatory and autoimmune diseases. IL-33 can be produced by various types of tissues and cells and induce gene expression of Th2-associated cytokines via binding to the orphan receptor ST2. By promoting Th2 type immune response, IL-33 plays important roles in the allergy, whereas its function in autoimmune diseases attracts more attention. Recent studies reported the correlation of IL-33 with rheumatic diseases, and most of them found that the IL-33 expression levels were consistent with disease activity and development. Furthermore, evidence has indicated that IL-33-related treatment may ameliorate the pathogenic conditions and attenuate disease progression of those rheumatic diseases. Therefore, elucidation of the roles of IL-33 in rheumatic diseases would be beneficial to understand the pathogenesis and therapy of these diseases. In this paper, we will summarize the roles of IL-33 in the rheumatic diseases.

Infliximab for the treatment of refractory noninfectious Uveitis: a study of 88 patients with long-term follow-up

OBJECTIVE

To establish the safety and efficacy of infliximab for the treatment of refractory noninfectious uveitis.

DESIGN

Retrospective, interventional, noncomparative cohort study.

PARTICIPANTS

Eighty-eight patients from a single-center private practice.

METHODS

Patients with chronic, recalcitrant uveitis treated with infliximab (Remicade; Janssen Biotech, Inc., Titusville, NJ) were identified through an electronic medical record database. All charts were reviewed for sex, diagnosis, location of inflammation, presence of vasculitis, prior immunomodulatory treatments, duration of infliximab treatment, dose received, secondary side effects, and other medications continued while receiving treatment with infliximab.

MAIN OUTCOME MEASURES

The primary outcome measures were the rate of remission, time to remission, relapse rate, failure rate, and patient tolerance. Additional analysis aimed to identity risk factors that would predict a higher success rate of infliximab to treat various types of noninfectious uveitis.

RESULTS

Of the 72 patients (81.8%) who achieved clinical remission while being treated with infliximab, 42 (58.3%) required additional immunomodulatory medications. At 7, 18.1, and 44.7 weeks, 25%, 50%, and 75% of patients, respectively, achieved clinical remission off all corticosteroids. Thirty-two patients (36.4%) experienced at least 1 side effect while on infliximab therapy, and 17 patients (19.3%) discontinued treatment secondary to 1 or more intolerable side effects. The most common adverse effects were skin rash (9.1%) and fatigue (8%). Factors associated with a higher chance to achieve clinical remission were nonidiopathic uveitis (P < 0.001), intermediate or panuveitis (P < 0.001), absence of vasculitis (P < 0.001), and a starting dose ≥5 mg/kg (P < 0.011).

CONCLUSIONS

Infliximab induces a high rate of complete clinical remission in recalcitrant uveitis and is well tolerated by most patients.

Molecular targeting of hepatocyte growth factor by an antagonist, NK4, in the treatment of rheumatoid arthritis

Introduction

Hepatocyte growth factor (HGF) is a potent proangiogenic molecule that induces neovascularization. The HGF antagonist, NK4, competitively antagonizes HGF binding to its receptor. In the present study, we determined the inhibitory effect of NK4 in a rheumatoid arthritis (RA) model using SKG mice.

Methods

Arthritis was induced in SKG mice by a single intraperitoneal injection of β-glucan. Recombinant adenovirus containing NK4 cDNA (AdCMV.NK4) was also injected intravenously at the time of or 1 month after β-glucan injection. Ankle bone destruction was examined radiographically. The histopathologic features of joints were examined using hematoxylin and eosin and immunohistochemical staining. Enzyme-linked immunosorbent assays were used to determine the serum levels of HGF, interferon γ (IFN-γ, interleukin 4 (IL-4) and IL-17 production by CD4⁺ T cells stimulated with allogeneic spleen cells.

Results

The intravenous injection of AdCMV.NK4 into SKG mice suppressed the progression of β-glucan-induced arthritis. Bone destruction was also inhibited by NK4 treatment. The histopathologic findings of the ankles revealed that angiogenesis, inflammatory cytokines and RANKL expression in synovial tissues were significantly inhibited by NK4 treatment. Recombinant NK4 (rNK4) proteins inhibited IFN-γ, IL-4 and IL-17 production by CD4⁺ T cells stimulated with allogeneic spleen cells.

Conclusions

These results indicate that NK4 inhibits arthritis by inhibition of angiogenesis and inflammatory cytokine production by CD4⁺ T cells. Therefore, molecular targeting of angiogenic inducers by NK4 can potentially be used as a novel therapeutic approach for the treatment of RA.

Etanercept for the treatment of rheumatoid arthritis

BACKGROUND

Etanercept is a soluble tumour necrosis factor alpha-receptor disease-modifying anti-rheumatic drug (DMARD) for the treatment of rheumatoid arthritis (RA).

OBJECTIVES

The purpose of this review was to update the previous Cochrane systematic review published in 2003 assessing the benefits and harms of etanercept for the treatment of RA. In addition, we also evaluated the benefits and harms of etanercept plus DMARD compared with DMARD monotherapy in those people with RA who are partial responders to methotrexate (MTX) or any other traditional DMARD.

SEARCH METHODS

Five electronic databases were searched from 1966 to February 2003 with no language restriction. The search was updated to January 2012. Attempts were made to identify other studies by contact with experts, searching reference lists and searching trial registers.

SELECTION CRITERIA

All controlled trials (minimum 24 weeks' duration) comparing four possible combinations: 1) etanercept (10 mg or 25 mg twice weekly) plus a traditional DMARD (either MTX or sulphasalazine) versus a DMARD, 2) etanercept plus DMARD versus etanercept alone, 3) etanercept alone versus a DMARD or 4) etanercept versus placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias of the trials.

MAIN RESULTS

Three trials were included in the original version of the review. An additional six trials, giving a total of 2842 participants, were added to the 2012 update of the review. The trials were generally of moderate to low risk of bias, the majority funded by pharmaceutical companies. Follow-up ranged from six months to 36 months.BenefitAt six to 36 months the American College of Rheumatology (ACR) 50 response rate was statistically significantly improved with etanercept plus DMARD treatment when compared with a DMARD in those people who had an inadequate response to any traditional DMARD (risk ratio (RR) 2.0; 95% confidence interval (CI) 1.3 to 2.9, absolute treatment benefit (ATB) 38%; 95% CI 13% to 59%) and in those people who were partial responders to MTX (RR 11.7; 95% CI 1.7 to 82.5, ATB 36%). Similar results were observed when pooling data from all participants (responders or not) (ACR 50 response rates at 24 months: RR 1.9; 95% CI 1.3 to 2.8, ATB 29%; 36 months: RR 1.6; 95% CI 1.3 to 1.9, ATB 24%). Statistically significant improvement in physical function and a higher proportion of disease remission were observed in combination-treated participants compared with DMARDs alone ((mean difference (MD) -0.36; 95% CI -0.43 to -0.28 in a 0-3 scale) and (RR 1.92; 95% CI 1.60 to 2.31), respectively) in those people who had an inadequate response to any traditional DMARD. All changes in radiographic scores were statistically significantly less with combination treatment (etanercept plus DMARD) compared with MTX alone for all participants (responders or not) (Total Sharp Score (TSS) (scale = 0 to 448): MD -2.2, 95% CI -3.0 to -1.4; Erosion Score (ES) (scale = 0 to 280): MD -1.6; 95% CI -2.4 to -0.9; Joint Space Narrowing Score (JSNS) (scale = 0 to 168): MD -0.7; 95% CI -1.1 to -0.2), and with combination treatment compared with etanercept alone (TSS: MD -1.1; 95% CI -1.8 to -0.5; ES: MD -0.7; 95% CI -1.1 to -0.2; JSNS: MD -0.5, 95% CI -0.7 to -0.2). The estimate of irreversible physical disability over 10 years given the radiographic findings was 0.45 out of 3.0.When etanercept monotherapy was compared with DMARD monotherapy, there was generally no evidence of a difference in ACR50 response rates when etanercept 10 mg or 25 mg was used; at six months etanercept 25 mg was significantly more likely to achieve ACR50 than DMARD monotherapy but this difference was not found at 12, 24 or 36 months. TSS and ES radiographic scores were statistically significantly improved with etanercept 25 mg monotherapy compared with DMARD (TSS: MD -0.7; 95% CI -1.4 to 0.1; ES: MD -0.7; 95% CI -1.0 to -0.3) but there was no evidence of a statistically significant difference between etanercept 10 mg monotherapy and MTX.HarmsThere was no evidence of statistically significant differences in infections or serious infections between etanercept plus DMARD and DMARD alone at any point in time. Infection rates were higher in people receiving etanercept monotherapy compared with DMARD; however, there were no differences regarding serious infections. For those participants who had an inadequate response to DMARDs, the rate of total withdrawals was lower for the etanercept plus DMARD group compared with DMARD alone (RR 0.53; 95% CI 0.36 to 0.77, ATB 18%). No other statistically significant differences were observed in any of the assessed comparisons.

AUTHORS' CONCLUSIONS

Etanercept 25 mg administered subcutaneously twice weekly together with MTX was more efficacious than either etanercept or MTX monotherapy for ACR50 and it slowed joint radiographic progression after up to three years of treatment for all participants (responders or not). There was no evidence of a difference in the rates of infections between groups.

Anti-tumor and anti-metastatic actions of wogonin isolated from Scutellaria baicalensis roots through anti-lymphangiogenesis

Tumor growth and metastasis are associated with angiogenesis and lymphangiogenesis through the production of vascular endothelial growth factor (VEGF) or VEGF-C in tumors, and the phosphorylation of VEGF receptor (VEGFR)-2 or VEGFR-3 in vascular endothelial cells or lymphatic endothelial cells (LECs). Tumor-associated macrophages (TAMs) play an important role in tumor lymphangiogenesis, and consequently stimulate metastasis through the lymphatic system to lymph nodes. We examined the effects of wogonin isolated from Scutellaria baicalensis roots on tumor growth and metastasis using a highly metastatic model in osteosarcoma LM8-bearing mice. Wogonin (25 and 50 mg/kg, twice daily) reduced tumor growth and metastasis to the lung, liver and kidney, angiogenesis (CD31-positive cells), lymphangiogenesis (LYVE-1-positive cells), and TAM (F4/80-positive cell) numbers in the tumors of LM8-bearing mice. Wogonin (10-100 μM) also inhibited increases in IL-1β production and cyclooxygenase (COX)-2 expression induced by lipopolysaccharide in THP-1 macrophages. Wogonin had no effect on VEGF-C production in LM8 cells, or VEGFR-3 expression in human lymphatic endothelial cells (HLECs), however, it inhibited VEGF-C-induced VEGFR-3 phosphorylation in HLECs. The anti-tumor and anti-metastatic actions of wogonin may be associated with the inhibition of VEGF-C-induced lymphangiogenesis through a reduction in VEGF-C-induced VEGFR-3 phosphorylation by the inhibition of COX-2 expression and IL-1β production in TAMs.

Linking systemic angiogenic factors (VEGF, angiogenin, TIMP-2) and Doppler ultrasound to anti-inflammatory treatment in rheumatoid arthritis

OBJECTIVE

To evaluate an association between synovial Doppler flow and serum levels of vascular endothelial growth factor (VEGF), angiogenin and TIMP-2 in patients with rheumatoid arthritis during anti-inflammatory treatment with glucocorticoids and TNF-α inhibitors.

METHODS

Inflamed wrists of 15 patients with rheumatoid arthritis (RA) were examined by two independent ultrasound investigators prior to and at days 3, 7, 14 and 42 after the initiation of treatment with glucocorticoids in therapy-naïve patients or after the beginning of a therapy with a TNF-α inhibitor in patients with DMARD failure. Quantitative three-dimensional power Doppler ultrasonographic assessment of synovial vascularization was compared at each visit with serum levels of VEGF, angiogenin and TIMP-2.

RESULTS

In the glucocorticoid group, synovial Doppler signals decreased significantly at day 3 (-44%; P=0.003) in comparison to a delayed decrease in the TNF-α inhibitor group after 6 weeks (-46%; P=0.001). A significant reduction of serum VEGF levels could be determined with a delay of 1 week after the decrease of Doppler activity but no correlation was found between both parameters (rho: P=0.7; r=-0.03). Angiogenin concentrations decreased in the TNF group and increased in the GC group. Levels of TIMP-2 did not change significantly in both groups.

CONCLUSION

The decrease of serum VEGF levels under treatment with glucocorticoids or TNF-α inhibitors followed the reduction of the intra-articular synovial Doppler flow. This result supports the idea that the reduction of synovial perfusion due to anti-inflammatory treatment is not regulated by systemic VEGF, but that the inflamed joints are the source for circulating VEGF.

What Have We Learned about the Pathogenesis of Rheumatoid Arthritis from TNF-Targeted Therapy?

Studies of cytokine regulation in rheumatoid arthritis led to the development of TNFα inhibitors which are now used for a number of indications, including rheumatoid arthritis, inflammatory bowel disease, psoriasis, psoriatic arthritis, and ankylosing spondylitis. The widespread use of biologics in the clinic offers unique opportunities for probing disease pathogenesis and this paper provides an overview of rheumatoid arthritis, with a particular emphasis on the impact of anti-TNFα therapy on pathogenetic mechanisms. An overview is also provided on the most commonly used animal models that mimic RA, including adjuvant-induced arthritis, collagen-induced arthritis, TNFα-transgenic mice, and the K/BxN and SKG models. These models have led to significant discoveries relating to the importance of pro-inflammatory cytokines in the pathogenesis of rheumatoid arthritis, resulting from disregulation of the normally finely tuned balance of pro- and anti-inflammatory cytokine signalling. In addition, experimental evidence is discussed suggesting how genetic and environmental factors can contribute to disease susceptibility. The role of effector and regulatory T cells is discussed in the light of the relatively disappointing therapeutic effects of T cell modifying agents such as anti-CD4 antibody and cyclosporin. It is concluded that comprehensive analyses of mechanisms of action of biologics and other drugs entering the clinic will be essential to optimise therapy, with the ultimate aim of providing a cure.

c-Jun N-Terminal Kinase in Inflammation and Rheumatic Diseases

The c-Jun N-terminal kinases (JNKs) are members of the mitogen-activated protein kinase (MAPK) family and are activated by environmental stress. JNK is also activated by proinflammatory cytokines, such as TNF and IL-1, and Toll-like receptor ligands. This pathway, therefore, can act as a critical convergence point in immune system signaling for both adaptive and innate responses. Like other MAPKs, the JNKs are activated via the sequential activation of protein kinases that includes two dual-specificity MAP kinase kinases (MKK4 and MKK7) and multiple MAP kinase kinase kinases. MAPKs, including JNKs, can be deactivated by a specialized group of phosphatases, called MAP kinase phosphatases. JNK phosphorylates and regulates the activity of transcription factors other than c-Jun, including ATF2, Elk-1, p53 and c-Myc and non-transcription factors, such as members of the Bcl-2 family. The pathway plays a critical role in cell proliferation, apoptosis, angiogenesis and migration. In this review, an overview of the functions that are related to rheumatic diseases is presented. In addition, some diseases in which JNK participates will be highlighted.

Gene expression profiling and functional analysis of angiogenic markers in murine collagen-induced arthritis

Introduction

Dysregulated angiogenesis is implicated in the pathogenesis of rheumatoid arthritis (RA). To provide a more profound understanding of arthritis-associated angiogenesis, we evaluated the expression of angiogenesis-modulating genes at onset, peak and declining phases of collagen-induced arthritis (CIA), a well-established mouse model for RA.

Methods

CIA was induced in DBA/1 mice with type II collagen. Functional capillary density in synovial tissue of knee joints was determined by intravital fluorescence microscopy. To assess the ability of arthritic joint homogenates to induce angiogenesis, an endothelial chemotaxis assay and an in vivo matrigel plug assay were employed. The temporal expression profile of angiogenesis-related genes in arthritic paws was analysed by quantitative real-time RT-PCR using an angiogenesis focused array as well as gene specific PCR. Finally, we investigated the therapeutic effect of a monoclonal antibody specifically blocking the binding of VEGF to neuropilin (NRP)-1.

Results

Although arthritic paw homogenates displayed angiogenic activity in vitro and in vivo, and synovia of arthritic paws appeared highly vascularised on histological examination, the functional capillary density in arthritic knee synovia was significantly decreased, whereas capillary diameter was increased. Of the 84 genes analysed, 41 displayed a differential expression in arthritic paws as compared to control paws. Most significant alterations were seen at the peak of clinical arthritis. Increased mRNA expression could be observed for VEGF receptors (Flt-1, Flk-1, Nrp-1, Nrp-2), as well as for midkine, hepatocyte growth factor, insulin-like growth factor-1 and angiopoietin-1. Signalling through NRP-1 accounted in part for the chemotactic activity for endothelial cells observed in arthritic paw homogenates. Importantly, therapeutic administration of anti-NRP1^B antibody significantly reduced disease severity and progression in CIA mice.

Conclusions

Our findings confirm that the arthritic synovium in murine CIA is a site of active angiogenesis, but an altered balance in the expression of angiogenic factors seems to favour the formation of non-functional and dilated capillaries. Furthermore, our results validate NRP-1 as a key player in the pathogenesis of CIA, and support the VEGF/VEGF receptor pathway as a potential therapeutic target in RA.

An observational study of endothelial function in early arthritis

BACKGROUND

Endothelial dysfunction is present in established rheumatoid arthritis, but it is not clear at what stage of the disease this abnormality develops. We set out to determine whether endothelial damage/dysfunction is present in a group of patients with early arthritis (EA) (new onset inflammatory arthritis, EA).

MATERIALS AND METHODS

Eighteen patients with EA, 48 healthy controls and 25 disease controls were recruited. Plasma was obtained for endothelial [von Willebrand factor (vWF) and soluble E-selectin] and angiogenesis markers (vascular endothelial growth factor and its receptor sFlt-1), adhesion molecules (intercellular adhesion molecule 1 and vascular cell adhesion molecule 1) and circulating endothelial cells (CECs, as a marker of endothelial damage). Microvascular endothelial function was assessed using laser Doppler perfusion imaging and macrovascular function using flow-mediated dilatation of the brachial artery.

RESULTS

von Willebrand factor and CECs (both P < 0.05) were significantly elevated in EA suggesting endothelial dysfunction and damage but were unrelated to classical laboratory markers of inflammation C-reactive protein, erythrocyte sedimentation rate or IL6. No other biomarkers was elevated in EA. Microvascular and macrovascular abnormalities were confined to endothelium-independent (smooth muscle cell) responses.

CONCLUSIONS

Endothelial damage/dysfunction is present early in the course of inflammatory arthritis but is not directly related to inflammation markers.

Hypoxia--a key regulator of angiogenesis and inflammation in rheumatoid arthritis

The importance of inflammation in rheumatoid arthritis (RA) is well understood. This knowledge has resulted in the development of anti-inflammatory therapies--either broadly acting (such as steroids) or more specific approaches (such as antibodies against TNF)--with biologic therapies (including TNF inhibitors) revolutionizing the treatment of RA. However, what is less well appreciated in RA are the links between inflammation, blood-vessel formation (angiogenesis) and cellular responses to changes in oxygen tension. Inadequate oxygenation, termed hypoxia, is thought to drive the increase in synovial angiogenesis that occurs in RA, through expression of hypoxia-inducible molecules, including vascular endothelial growth factor (VEGF). This process promotes further infiltration of inflammatory cells and production of inflammatory mediators, perpetuating synovitis. This Review highlights the molecular pathways activated by hypoxia, and how these pathways might interact with inflammatory signaling to promote and maintain synovitis in RA, with a particular focus on the response of macrophages to hypoxia in the context of RA. Successful treatment of RA, for example with anti-TNF antibodies, reduces levels of proangiogenic factors, including VEGF, and leads to normalization of the vasculature. These processes emphasise the close links between hypoxia, angiogenesis and inflammation in this disease and supports the concept that angiogenesis blockade could be of therapeutic benefit in RA.

Resistance--the true face of biological defiance

Biological therapeutics are widely used in chronic inflammatory and malignant disease. The underlying mechanisms of treatment failure for these drugs are poorly understood. Resistance to these biological agents and the further subdivision into intrinsic and acquired resistance are not clearly defined. In this review, we explore the current understanding of the mechanisms of action of several biological agents as well as the complex biological processes that underlie resistance. A better understanding of why biologicals fail might help to improve their single or combinational use and will ultimately help to alleviate disease burden more efficiently.

Histopathologic spectrum of psoriasiform skin reactions associated with tumor necrosis factor-α inhibitor therapy. A study of 16 biopsies

Tumor necrosis factor (TNF)-α inhibitors (anti-TNF-α biologic drugs), currently used to treat different autoimmune conditions, may be associated with cutaneous drug reactions. New onset or worsening of psoriasis and psoriasis-like reactions have been reported in these patients. However, not much is known about the different histopathologic patterns of such skin lesions. The aim of this study was to evaluate the pathologic spectrum of clinically papulosquamous to pustular "psoriasiform" lesions in this setting. Sixteen biopsies from 9 patients on anti-TNF-α therapy for rheumatoid arthritis (n = 7), Crohn disease (n = 1), and Behçet disease (n = 1) who developed a "psoriasiform" skin rash during treatment were included in this study. None of the patients had history of psoriasis. Five patients (10 biopsies) showed a psoriasis-like pattern that varied from that seen in guttate lesions (4 biopsies), to well-established plaques (3 biopsies) to pustular psoriasis (3 biopsies). Three patients (4 biopsies) showed an interface/lichenoid dermatitis mimicking lichen planus. Two patients (2 biopsies) showed features of pustular folliculitis. Eosinophils varied from none (2 biopsies) to scattered (7 biopsies) to numerous (7 biopsies). Plasma cells were present in most cases. All pustular lesions had negative cultures. In conclusion, anti-TNF drugs elicit a spectrum of cutaneous reactions that go beyond the classical eosinophilic-rich hypersensitivity reaction and may closely mimic primary dermatitis. In addition to psoriasis-like lesions, lichen planus-like dermatitis and sterile pustular folliculitis should be included in the list of anti-TNF-α-related drug reactions. Because the different histopathologic findings may be subtle, clinical correlation is crucial to make the diagnosis.

Serum concentrations of VEGF and TGF-β1 during exclusive enteral nutrition in IBD

BACKGROUND AND AIM

Exclusive enteral nutrition (EEN) is an effective method of treatment in achieving remission in inflammatory bowel disease (IBD); however, its mechanism of action is still poorly understood. The objective of our study was to assess the influence of EEN on serum vascular endothelial growth factor (VEGF) and transforming growth factor-beta 1 (TGF-β1) in children and adolescents with IBD.

PATIENTS AND METHODS

Thirty-nine children and adolescents with IBD (24 with Crohn disease [CD] and 15 with ulcerative colitis [UC]) and 25 healthy controls were enrolled in the study. VEGF and TGF-β1 were assessed at the baseline and after 2 and 4 weeks of EEN in CD and UC groups and once in controls using enzyme-linked immunosorbent assay immunoassays.

RESULTS

At the baseline, we found increased serum VEGF in the CD versus UC group and controls (P < 0.05) and serum TGF-β1 in the UC versus CD group and controls (P < 0.05). During EEN, VEGF decreased in the UC and CD groups, whereas TGF-β1 increased in the CD group and decreased in the UC group. The CD group achieved disease remission faster than the UC group, and the weight gain of patients with CD during EEN was higher compared with patients with UC. Additionally, TGF-β1 concentration correlated with protein and energies daily intake in the CD group (R = 0.95; P < 0.05).

CONCLUSIONS

Different effectiveness of EEN in achieving remission in CD and UC may result from a modification of growth factor production. EEN stimulated TGF-β1 production in CD but not in UC, which possibly resulted in higher effectiveness of EEN in this group of patients.

Involvement of IL-33 in the pathogenesis of rheumatoid arthritis: the effect of etanercept on the serum levels of IL-33

To investigate the role of interleukin (IL)-33 in rheumatoid arthritis (RA) patients, we measured the serum levels of IL-33 in RA patients before and after the administration of etanercept. Twenty-four patients with RA were treated with etanercept. Clinical and laboratory examinations, including serum levels of C-reactive protein (CRP) and hemoglobin (Hb); white blood cell (WBC) and red blood cell (RBC) counts; and the Disease Activity Score of 28 joints including CRP (DAS28-CRP), were performed at the baseline and at 3 and 6 months after the initial treatment with etanercept. The mean serum IL-33 levels had decreased significantly at 3 and 6 months after the initial treatment with etanercept. Serum IL-33 levels showed a significant correlation with the number of tender joints, CRP, DAS28-CRP, and the WBC count, and an inverse correlation with the RBC count and Hb level. These findings indicated that the decrease of serum IL-33 levels was a novel function of etanercept, shown for the first time in this study. Measurement of serum levels of IL-33 may become a useful control marker for RA treatment.

Tacrolimus (FK506) inhibits interleukin-1β-induced angiopoietin-1, Tie-2 receptor, and vascular endothelial growth factor through down-regulation of JNK and p38 pathway in human rheumatoid fibroblast-like synoviocytes

OBJECT

This study aimed to identify the regulatory effect of tacrolimus on the interleukin-1β (IL-1β)-induced expressions of angiopoietin-1 (Ang-1), Tie-2 receptor (Tie-2), and vascular endothelial growth factor (VEGF) in human rheumatoid fibroblast-like synoviocytes (FLS) and to determine the regulatory mechanism in the mitogen-activated protein kinases (MAPKs) signaling pathway.

METHODS

IL-1β-induced Ang-1, Tie-2, and VEGF expressions with and without tacrolimus were measured in cultured FLS using real time-polymerase chain reaction, enzyme-linked immunosorbent assay, Western blotting, and immunofluorescence staining. The effect of tacrolimus on the regulation of Ang-1, Tie-2 and VEGF expressions through the MAPK signaling pathway was identified by Western blotting and immunofluorescence staining.

RESULTS

IL-1β appeared to induce marked expressions of Ang-1, Tie-2, and VEGF in cultured FLS. Tacrolimus significantly inhibited Ang-1, Tie-2, and VEGF mRNA and protein in cultured FLS treated with 10 ng/ml IL-1β. In addition, expressions of these angiogenic molecules were shown to involve all three of the studied MAPK signaling pathways, including ERK, JNK, and p38. However, the inhibitory effects of tacrolimus on Ang-1, Tie-2, and VEGF proteins were regulated by blocking the phosphorylations of JNK and p38 MAPK, but not that of ERK.

CONCLUSION

This study demonstrates that tacrolimus inhibits the expressions of Ang-1, Tie-2, and VEGF by blocking the activations of the IL-1β-mediated JNK and p38 MAPK pathways in human FLS. This suggests that tacrolimus contributes to the suppression of angiogenesis in the pathogenesis of RA.

Muscle hypoxia in rheumatoid hands: does it play a role in ulnar drift?

PURPOSE

The cause of ulnar drift in patients with rheumatoid arthritis (RA) is unknown. It may occur because of external forces applied to the fingers during normal use. Alternatively, it may arise after changes in the internal forces on the anatomy of the digits owing to alterations in the supporting structures of the joints or their control mechanisms, or both. Intrinsic muscle tightness, which is commonly seen in RA hands, may be the result of adaptive shortening or a direct consequence of RA. Previous studies carried out by our group have shown that joints, tendons, and associated synovium in RA hands are consistently hypoxic. Therefore, we formed the hypothesis that there is a difference in hand/forearm muscle oxygen tension in RA versus non-RA.

METHODS

We measured tissue oxygen levels in the intrinsic muscles of the hands and forearm muscles of 29 patients with a diagnosis of RA, who were undergoing elective surgery. We measured oxygen levels using a microelectrode technique. A total of 31 patients without RA undergoing elective surgery served as matched controls.

RESULTS

Our results show that the intrinsic muscles of RA patients are significantly more hypoxic than in non-RA controls. Moreover, there is a trend in the RA group for increasing hypoxia in a radial-to-ulnar direction when comparing the different intrinsic muscle groups. We also demonstrate that forearm and thenar and hypothenar muscles are significantly more hypoxic in RA versus non-RA patients.

CONCLUSIONS

The intrinsic muscle weakness, intrinsic tightness, and muscle wasting observed in RA may not be due to disuse atrophy resulting from joint disease. From our data, we speculate that these changes may be the result of direct muscular involvement in RA leading to muscle hypoxia.

CD248 and its cytoplasmic domain: a therapeutic target for arthritis

OBJECTIVE

CD248 is a transmembrane glycoprotein expressed on the surface of activated perivascular and fibroblast-like cells. This study was undertaken to explore the function of CD248 and its cytoplasmic domain in arthritis.

METHODS

Synovial tissue biopsy samples from healthy controls, from patients with psoriatic arthritis (PsA), and from patients with rheumatoid arthritis (RA) were stained for CD248. Transgenic mice that were CD248-deficient (CD248-knockout [CD248(KO/KO) ]) or mice with CD248 lacking the cytoplasmic domain (CD248(CyD/CyD) ) were generated. Collagen antibody-induced arthritis (CAIA) was induced in these mice and in corresponding wild-type (WT) mice as controls. Clinical signs and histologic features of arthritis were evaluated. Cytokine levels were determined by enzyme-linked immunosorbent assay, and the number of infiltrating inflammatory cells was quantified by immunohistochemistry. In vitro studies were performed with fibroblasts from CD248-transgenic mouse embryos to explain the observed effects on inflammation.

RESULTS

Immunostaining of synovium from patients with PsA and patients with RA and that from mice after the induction of CAIA revealed strong CD248 expression in perivascular and fibroblast-like stromal cells. CD248(KO/KO) and CD248(CyD/CyD) mice had less severe arthritis, with lower plasma levels of proinflammatory cytokines, as compared with WT controls. Moreover, the joints of these mice had less synovial hyperplasia, reduced accumulation of inflammatory cells, and less articular cartilage and bone damage. Tumor necrosis factor α-induced monocyte adhesion to CD248(CyD/CyD) fibroblasts was impaired. CD248(CyD/CyD) fibroblasts exhibited reduced expression of hypoxia-inducible factor 1α, placental growth factor, vascular endothelial growth factor, and matrix metalloproteinase 9 activity in response to transforming growth factor β.

CONCLUSION

CD248 contributes to synovial hyperplasia and leukocyte accumulation in inflammatory arthritis, the effects of which are mediated partly via its cytoplasmic domain. CD248 is therefore a potential new target in the treatment of arthritis.

Quantitative Power Doppler Ultrasonography Is a Sensitive Measure of Metacarpophalangeal Joint Synovial Vascularity in Rheumatoid Arthritis and Declines Significantly Following a 2-week Course of Oral Low-dose Corticosteroids

Objective.

To investigate the stability over 2 weeks of ultrasonographic assessments of synovial thickness and vascularity in all 10 metacarpophalangeal joints of subjects with rheumatoid arthritis (RA) with a range of disease activities as measured by the validated Disease Activity Score-28 joint score (DAS28-ESR). And in subjects with severe disease activity, to compare the sensitivity of these measurements, acute-phase markers, and vascular endothelial growth factor to change in response to 2 weeks of oral prednisolone (7.5 mg daily).

Methods.

A group of 38 subjects with RA were enrolled, 13 (mean DAS28 2.1), 14 (mean DAS28 5.2), and 11 (mean DAS28 5.7) meriting oral corticosteroid treatment. Synovial thickness and vascularity were assessed by ultrasonography at 3 timepoints. Images were ranked by semiquantitative scale. Vascularity was also measured by quantitative determination of the power Doppler area (PDA).

Results.

In the whole RA cohort, baseline indices of synovial thickness and vascularity correlated with DAS28, as did PDA (r = 0.42, p < 0.05). In the RA groups on stable therapy, synovial thickness and vascularity showed little variation over 2 weeks. In the corticosteroid group, PDA had fold changes of −1.9-fold (p < 0.05) after 1 week and −2.2-fold (p < 0.05) after 2 weeks. These were the largest fold changes of all measured variables.

Conclusion.

Ultrasonographic measures can differentiate disease severity in RA correlating closely with DAS28. Quantitative power Doppler signal was significantly reduced within 1 week of oral prednisolone, a rapid kinetic suggesting that PDA may have value as a sensitive early marker of therapeutic response.

Anti-TNF therapy, from rationale to standard of care: what lessons has it taught us?

In the mid-1980s, new molecular tools enabled the biology of cytokine expression and regulation to be studied. Our group uncovered a TNF-dependent cascade in active rheumatoid synovium, suggesting that TNF might be a therapeutic target; this concept was supported in an animal model of the disease. The proof of concept was a series of clinical trials, which have led to marked changes in the therapy of human rheumatoid arthritis and subsequently of other diseases. The work with TNF clearly demonstrated the importance of cytokines in medicine as well as the capacity of mAbs (or receptor fusion proteins) to be used long-term in large populations, thus changing the therapeutic landscape.

Serum Levels and in Vitro Production of Th1- and Th2-Type Cytokines by Peripheral Blood Mononuclear Cells in Patients Suffering from Systemic Lupus Erythematosus

Th1-type and Th2-type cytokine profiles and adhesion molecules in the serum of patients suffering from systemic lupus erythematosus and the cytokine production by peripheral blood mononuclear cells (PBMC) were studied. Tumor necrosis factor-alpha (TNF-α), interferongamma (IFN-γ), interleukin-1β (IL-1β), IL-4, IL-10, IL-13, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were measured using ELISA technique in the sera of 16 systemic lupus erythematosus patients without vasculitis (SLE), 30 SLE patients with vasculitis (LV), and in 18 healthy controls. The cytokines were also measured in the culture media of unstimulated, concana valin-A (Con-A) and phorbol-12-myristate-13-acetate (PMA) stimulated PBMC. TNF-α serum levels were significantly elevated in both SLE and LV patients and those of IL-1β in SLE patients. TNF-α was also significantly increased in SLE compared to LV patients. Serum levels of all three Th-2 cytokines were significantly elevated in both SLE and LV patients compared to healthy controls. Serum IFN-γ and Th2 cytokine levels were significantly increased in patients with more active disease. Both ICAM-1 and VCAM-1 were significantly increased in SLE patients and only VCAM-1 in LV patients. ICAM-1 showed a significant correlation with IL-1β, IFN-γ, IL-4 and IL-10 in both patient groups. In the SLE group VCAM-1 correlated significantly only with ICAM-1, but in the LV group only with IL-1β and IFN-γ. Compared to healthy controls, basal TNF-α and IL-4 production by unstimulated PBMC derived from SLE patients were significantly increased. Con-A-stimulated PBMC of both SLE groups produced significantly more IFN-γ, IL-4 and IL-13 than Con-A-stimulated control cells. Con-A-stimulated cells derived from LV patients produced much more INF-γ than cells from SLE patients. PMA strongly stimulated INFγ, TNFα and IL-13 production by cells derived from both SLE groups but had no effect on IL-4 production. In addition, it had little if any effect on the production of INFγ and IL-13 by PBMC derived from healthy donors. These findings suggest that the altered pattern of cytokine production by PBMC may play an important role in the SLE pathophysiology, accounting for differences in the clinical expression of the disease. The differences in adhesion molecules production and their correlation with cytokines suggest ICAM-1 and VCAM-1 as useful markers in SLE patients stratification.

Effect of etanercept on serum levels of soluble cell adhesion molecules (sICAM-1, sVCAM-1, and sE-selectin) and vascular endothelial growth factor in patients with rheumatoid arthritis

OBJECTIVE

Endothelium and adhesion molecules are engaged in the pathogenesis of rheumatoid arthritis (RA). This study was undertaken to analyse the effect of etanercept on the levels of soluble cell adhesion molecules (sCAMs) and vascular endothelial growth factor (VEGF) in patients with active RA.

METHODS

Patients were receiving 50 mg/week of subcutaneous etanercept and 10-25 mg/week of methotrexate (MTX). Serum levels of soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), E-selectin (sE-selectin), and VEGF were measured by enzyme-linked immunosorbent assay (ELISA) in 18 RA patients (prior to injection) at 0, 3, 6, 9, and 12 months.

RESULTS

A decrease in serum levels of sICAM-1 (p<0.001), sVCAM-1 (p<0.01), sE-selectin (p<0.01), and VEGF (p<0.001) was observed in RA patients after 3 months of treatment with etanercept. Six months of therapy with etanercept prolonged the suppression of serum sICAM-1 (p<0.01) and even more remarkably diminished sVCAM-1, sE-selectin, and VEGF (in all cases p<0.001) concentrations as compared to baseline (month 0). Treatment also effectively diminished sICAM-1, sVCAM-1, and VEGF levels at months 9 and 12 (in all cases p<0.001), and less significantly sE-selectin (p<0.05 at month 9 and p<0.01 at month 12). The Disease Activity Score including a 28-joint count (DAS28) measured at 3, 6, 9, and 12 months decreased significantly compared to baseline (in all cases p<0.001).

CONCLUSION

Our study shows that, besides a rapid suppression of disease activity, serum sCAM and VEGF concentrations are downregulated following anti-tumour necrosis factor alpha (TNFalpha) therapy combined with MTX. Prolonged treatment with etanercept sustained or even more remarkably diminished the sCAM and VEGF serum concentrations.

Immature blood vessels in rheumatoid synovium are selectively depleted in response to anti-TNF therapy

Background

Angiogenesis is considered an important factor in the pathogenesis of Rheumatoid Arthritis (RA) where it has been proposed as a therapeutic target. In other settings, active angiogenesis is characterized by pathologic, immature vessels that lack periendothelial cells. We searched for the presence of immature vessels in RA synovium and analyzed the dynamics of synovial vasculature along the course of the disease, particularly after therapeutic response to TNF antagonists.

Methodology/Principal Findings

Synovial arthroscopic biopsies from RA, osteoarthritis (OA) and normal controls were analyzed by double labeling of endothelium and pericytes/smooth muscle mural cells to identify and quantify mature/immature blood vessels. To analyze clinicopathological correlations, a cross-sectional study on 82 synovial biopsies from RA patients with variable disease duration and severity was performed. A longitudinal analysis was performed in 25 patients with active disease rebiopsied after anti-TNF-α therapy. We found that most RA synovial tissues contained a significant fraction of immature blood vessels lacking periendothelial coverage, whereas they were rare in OA, and inexistent in normal synovial tissues. Immature vessels were observed from the earliest phases of the disease but their presence or density was significantly increased in patients with longer disease duration, higher activity and severity, and stronger inflammatory cell infiltration. In patients that responded to anti-TNF-α therapy, immature vessels were selectively depleted. The mature vasculature was similarly expanded in early or late disease and unchanged by therapy.

Conclusion/Significance

RA synovium contains a significant fraction of neoangiogenic, immature blood vessels. Progression of the disease increases the presence and density of immature but not mature vessels and only immature vessels are depleted in response to anti-TNFα therapy. The different dynamics of the mature and immature vascular fractions has important implications for the development of anti-angiogenic interventions in RA.

Changes in plasma IL-6, plasma VEGF and serum YKL-40 during Treatment with Etanercept and Methotrexate or Etanercept alone in Patients with Active Rheumatoid Arthritis Despite Methotrexate Therapy

Changes in plasma IL-6, plasma VEGF and serum YKL-40 were determined in rheumatoid arthritis (RA) patients during treatment with etanercept alone or in combination with methotrexate. Twenty-five patients with active RA (DAS28 ≥ 3.2) were randomized to receive etanercept (25 mg sc. biweekly) plus methotrexate (n = 12) or etanercept alone (n = 13). Plasma IL-6, plasma VEGF and serum YKL-40 were determined by ELISA. The 3 biomarkers and DAS28 scores were evaluated at baseline and after 4, 8, 12 and 16 weeks of treatment. At inclusion all patients had significantly (p < 0.001) elevated plasma IL-6, plasma VEGF and serum YKL-40 compared to healthy subjects. Eighteen patients responded to treatment (pooled data from both treatment groups), and they had significant (p < 0.05 to p < 0.001) decreases in plasma IL-6, plasma VEGF, serum YKL-40, ESR and DAS28 after 4 weeks of treatment and throughout the study (except serum YKL-40 at week 16). Plasma IL-6 showed the largest reductions. Non-responders had unchanged biomarkers. At week 16 the patients with DAS28 < 3.2 had lower levels compared to baseline values in plasma IL-6 (p = 0.005), plasma VEGF (p = 0.014), and ESR (p = 0.024).

Plasma IL-6, plasma VEGF and serum YKL-40, which reflect different aspects of the inflammatory process, may provide useful information regarding early differentiation of responders from non-responders.

Decreased TNF-alpha synthesis by macrophages restricts cutaneous immunosurveillance by memory CD4+ T cells during aging

Immunity declines during aging, however the mechanisms involved in this decline are not known. In this study, we show that cutaneous delayed type hypersensitivity (DTH) responses to recall antigens are significantly decreased in older individuals. However, this is not related to CC chemokine receptor 4, cutaneous lymphocyte-associated antigen, or CD11a expression by CD4⁺ T cells or their physical capacity for migration. Instead, there is defective activation of dermal blood vessels in older subject that results from decreased TNF-α secretion by macrophages. This prevents memory T cell entry into the skin after antigen challenge. However, isolated cutaneous macrophages from these subjects can be induced to secrete TNF-α after stimulation with Toll-like receptor (TLR) 1/2 or TLR 4 ligands in vitro, indicating that the defect is reversible. The decreased conditioning of tissue microenvironments by macrophage-derived cytokines may therefore lead to defective immunosurveillance by memory T cells. This may be a predisposing factor for the development of malignancy and infection in the skin during aging.

The vasculature in rheumatoid arthritis: cause or consequence?

The expansion of the synovial lining of joints in rheumatoid arthritis (RA) necessitates an increase in the vascular supply to the synovium, to cope with the increased requirement for oxygen and nutrients. New blood vessel formation -'angiogenesis'- is recognized as a key event in the formation and maintenance of the pannus in RA, suggesting that targeting blood vessels in RA may be an effective future therapeutic strategy. Although many pro-angiogenic factors have been demonstrated to be expressed in RA synovium, vascular endothelial growth factor (VEGF) has been demonstrated to a have a central involvement in the angiogenic process in RA. Nevertheless, it is unclear whether angiogenesis - whether driven by VEGF and/or other factors - should be considered as a 'cause' or 'consequence' of disease. This ongoing 'chicken vs. egg' debate is difficult, as even the success of angiogenesis inhibition in models of RA does not provide a direct answer to the question. This review will focus on the role of the vasculature in RA, and the contribution of different angiogenic factors in promoting disease. Although no data regarding the effectiveness of anti-angiogenic therapy in RA have been reported to date, the blockade of angiogenesis nevertheless looks to be a promising therapeutic avenue.

Circulating endothelial progenitor cells as a link between synovial vascularity and cardiovascular mortality in rheumatoid arthritis

Cardiovascular disease refers to the class of diseases that involve the heart and/or blood vessels (arteries and veins). Most Western countries face high and ever-increasing rates of cardiovascular disease. Each year, more Americans are killed by heart disease than by cancer. Diseases of the heart alone cause 30% of all deaths, with other diseases of the cardiovascular system causing substantial further deaths and disability. Indeed, cardiovascular disease is the major cause of death and disability in the USA and most European countries. The development of the vascular systems requires an intricate interplay of molecules such as vascular endothelial growth factor and endothelial progenitor cells. A defective vascular repair/regeneration is thought to be responsible for propagation of atherosclerosis, a key feature of cardiovascular disease. This is partly attributed to a reduction in the circulating endothelial progenitor cells in peripheral blood. Patients with rheumatoid arthritis (RA) have a higher than average incidence of cardiovascular disease in comparison with the general population, with an increased risk of stroke and myocardial infarction, and an increased risk of fatality following myocardial infarction. This review focuses on the current evidence linking the role played by endothelial progenitor cells to the development of cardiovascular disease and why this might relate to the increased risk observed in RA patients.

Translating molecular insights in autoimmunity into effective therapy

Autoimmunity and the pathogenesis of autoimmune diseases were a major focus of the Walter and Eliza Hall Institute, where I started my research career. After my initial studies on immune cell culture and immune regulation, I returned to an analysis of the pathogenesis of human autoimmunity in London. Linking upregulated antigen presentation to autoimmunity led to an investigation of the role of cytokines in rheumatoid arthritis (RA), in collaboration with Ravinder Maini. These experiments defined the concept of a TNF-dependent cytokine cascade driving the manifestations of RA, which led to successful clinical trials of anti-TNF monoclonal antibody in RA patients, heralding a major change in medical practice. This success was made possible by enthusiastic support from many laboratory and clinical colleagues and taught us that cytokines are important rate-limiting steps and hence good therapeutic targets. My current scientific challenge is exploring the hypothesis of whether all major medical needs can be approached via cytokine blockade.

Etanercept reduces the serum levels of macrophage chemotactic protein-1 in patients with rheumatoid arthritis

This study was performed to analyze the effect of etanercept, the soluble tumor necrosis factor-alpha (TNF-alpha) receptor, on the serum levels of several chemokines including monocyte chemotactic protein-1 (MCP-1), regulated upon activation normal T expressed and presumably secreted (RANTES), and granzyme B in rheumatoid arthritis (RA) patients. Twenty-eight patients with RA were administered etanercept once or twice a week for more than 6 months. Clinical and laboratory parameters were measured and serum levels of MCP-1, RANTES, and granzyme B were determined using enzyme-linked immunosorbent assay (ELISA) kits at baseline and at 3 and 6 months after the initial treatment. In addition, the levels of MCP-1, RANTES, and granzyme B produced by cultured synovial cells stimulated with TNF-alpha were measured. A significant decrease in serum MCP-1 levels was observed at 3 and 6 months after initial treatment with etanercept. Serum RANTES and granzyme B levels did not show significant changes. TNF-alpha induced MCP-1, RANTES, and granzyme B production in cultured synovial cells from RA patients. Serum MCP-1 levels were significantly correlated with the disease activity scores of 28 joints combined with CRP (DAS28-CRP), indicating the role of MCP-1 in the pathogenesis of rheumatoid inflammation. This study demonstrated that a reduction of MCP-1 production in RA patients was a newly determined effect of etanercept. Another cascade not associated with TNF-alpha may induce granzyme B and RANTES production in RA patients.

Hypoxia upregulates angiogenesis and synovial cell migration in rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is characterised by invasion of cartilage, bone and tendon by inflamed synovium. Previous studies in our laboratory have shown that hypoxia is a feature of RA synovitis. In the present study, we investigated the consequences of hypoxia on angiogenesis and synovial fibroblast migration in RA.

METHODS

Synovial tissue was harvested from RA patients, and synovial membrane cells were cultured under conditions either of hypoxia (1% oxygen) or normoxia (21% oxygen). Protein levels of matrix metalloproteinases (MMPs) and angiogenic factors were measured, while RNA was extracted for PCR quantification of MMPs/tissue inhibitors of MMP (TIMPs) and angiogenic factors. Migration of RA synovial fibroblasts through collagen, and the effect of RA synovial cell supernatants in an in vitro angiogenesis assay, were utilised to determine the functional relevance of changes in mRNA/protein.

RESULTS

We observed upregulation under hypoxic conditions of MMPs responsible for collagen breakdown, specifically collagenase MMP-8, and the gelatinases MMP-2 and MMP-9, at both mRNA and protein levels. Increased MT1-MMP mRNA was also observed, but no effect on TIMP-1 or TIMP-2 was detected. RA fibroblast migration across collagen was significantly increased under hypoxic conditions, and was dependent on MMP activity. Furthermore, expression of angiogenic stimuli, such as vascular endothelial growth factor (VEGF), and VEGF/placental growth factor heterodimer, was also increased. Crucially, we show for the first time that hypoxia increased the angiogenic drive of RA cells, as demonstrated by enhanced blood vessel formation in an in vitro angiogenesis assay.

CONCLUSIONS

Hypoxia may be responsible for rendering RA synovial lining proangiogenic and proinvasive, thus leading to the debilitating features characteristic of RA.

Osteopontin: a new emerging role in psoriasis

Osteopontin (OPN) is a phosphorylated acidic glycoprotein produced by cells of the immune system, epithelial tissue, smooth muscle cells, osteoblasts, and tumor cells. OPN interacts with integrins and CD44 to enhance Th1 and inhibit Th2 cytokine expression. The involvement of this molecule in the onset of psoriasis has not previously been studied. Here, we demonstrate that OPN is expressed in peripheral blood mononuclear cells and in skin biopsies of psoriatic patients. The study was conducted on 30 patients affected with plaque psoriasis, and on 11 healthy donors. Two blood samples and two skin samples from patients affected with atopic dermatitis were used as control for Th2 typical inflammatory skin disease. The analysis of IL-1beta, IFN-gamma, TauNuF-alpha, IL-8, and ICAM-1 showed the characteristic Th1 pattern in all the psoriatic blood and skin samples analyzed. This study offers an opportunity for understanding inflammation in psoriasis and supports the hypothesis that OPN could represent a potential target for therapeutic intervention in psoriatic patients.

IL-6/sIL-6R trans-signalling, but not TNF-alpha induced angiogenesis in a HUVEC and synovial cell co-culture system

Angiogenesis in synovia is a characteristic of RA patients. We examined whether IL-6 or TNF-alpha induce tubule formation in a co-culture system of fibroblast-like synovial cells from RA patients (RA-FLS) and human umbilical vein endothelial cells (HUVEC). The effects of IL-6 and TNF-alpha on the expression of angiogenic factors in RA-FLS and HUVEC, and the proliferation of HUVEC were also studied. IL-6 + sIL-6R induced tubule formation, whereas IL-6 alone did not. IL-6/sIL-6R-induced tubule formation was completely suppressed by the addition of either anti-IL-6R or anti-VEGF antibody. TNF-alpha did not induce tubule formation. On the contrary, it decreased CD31-positive area compared with the control. IL-6 + sIL-6R augmented VEGF production in RA-FLS, whereas IL-6 alone did not. Anti-IL-6R antibody suppressed IL-6/sIL-6R-induced VEGF production, but not spontaneous VEGF production. In contrast, TNF-alpha did not induce VEGF production from RA-FLS and HUVEC. IL-6 + sIL-6R stimulation of RA-FLS strongly induced mRNA expression of VEGF, but not of other angiogenic factors, such as EGF, bFGF, TGF-beta, IL-1, TNF-alpha and IL-8. Neither IL-6 nor IL-6/sIL-6R promoted HUVEC proliferation, whereas TNF-alpha significantly inhibited VEGF-induced HUVEC proliferation. In conclusion, IL-6/sIL-6R complex showed angiogenic activity via the production of VEGF from RA-FLS, but TNF-alpha was anti-angiogenic in our experimental system.

Inhibitory effects of erythromycin on wear debris-induced VEGF/Flt-1 gene production and osteolysis

OBJECTIVES

A highly vascularized and inflammatory periprosthetic tissue augments the progress of aseptic loosening, a major clinical problem after total joint replacement. The purpose of this study is to investigate the effect of erythromycin (EM) on ultra high molecular weight polyethylene (UHMWPE) particle-induced VEGF/VEGF receptor 1 (Flt-1) gene production and inflammatory osteolysis in a mouse model.

METHODS

UHMWPE particles were introduced into established air pouches on BALB/c mice, followed by implantation of calvaria bone from syngeneic littermates. EM treatment started 2 weeks after bone implantation (5 mg/kg day, i.p. injection). Mice without drug treatment as well as mice injected with saline alone were included. Pouch tissues were harvested 2 weeks after bone implantation. Expression of VEGF, Flt-1, RANKL, IL-1, TNF and CD68 was measured by immunostain and RT-PCR, and implanted bone resorption was analyzed by micro-CT (muCT).

RESULTS

Exposure to UHMWPE induced pouch tissue inflammation, increase of VEGF/Flt-1 proteins, and increased bone resorption. EM treatment significantly improved UHMWPE particle-induced tissue inflammation, reduced VEGF/Flt-1 protein expression, and diminished the number of TRAP(+) cells, as well as the implanted bone resorption.

CONCLUSION

This study demonstrated that EM inhibited VEGF and Flt-1 gene expression. The molecular mechanism of EM action on VEGF/Flt-1 signaling-mediated osteoclastogenesis warrants further investigation.

[Interleukin 6 in the physiopathology of rheumatoid arthritis]

Interleukin (IL) 6 was identified in 1986 as a factor produced by T lymphocytes, that mediates growth and immunoglobulin synthesis on B lymphocytes. IL-6 is a member of a large cytokine family sharing a gp130 membrane receptor. This receptor mediates specific Jak/STAT3 activation, which induces widespread expression of pro-inflammatory and immunoregulatory genes. IL-6 mediates potent systemic responses, in organs distant from its local inflammatory sources, in a prominent fashion compared to other cytokines. Most specific effects involve hematopoiesis and hepatic acute phase reactants synthesis. IL-6 became a rheumatoid arthritis (RA) target due to its pro-inflammatory and joint destructive potential, as well as its participation in T and B immunoregulation. The therapeutic success of tocilizumab has confirmed IL-6 as an RA target. Although additional studies on the participation of IL-6 in RA physiopathology are needed, a number of indirect data point to a relevant position in this setting.

Hypoxia. The role of hypoxia and HIF-dependent signalling events in rheumatoid arthritis

An adequate supply of oxygen and nutrients is essential for survival and metabolism of cells, and consequentially for normal homeostasis. Alterations in tissue oxygen tension have been postulated to contribute to a number of pathologies, including rheumatoid arthritis (RA), in which the characteristic synovial expansion is thought to outstrip the oxygen supply, leading to areas of synovial hypoxia and hypoperfusion. Indeed, the idea of a therapeutic modality aimed at 'starving' tissue of blood vessels was born from the concept that blood vessel formation (angiogenesis) is central to efficient delivery of oxygen to cells and tissues, and has underpinned the development of anti-angiogenic therapies for a range of cancers. An important and well characterized 'master regulator' of the adaptive response to alterations in oxygen tension is hypoxia-inducible factor (HIF), which is exquisitely sensitive to changes in oxygen tension. Activation of the HIF transcription factor signalling cascade leads to extensive changes in gene expression, which allow cells, tissues and organisms to adapt to reduced oxygenation. One of the best characterized hypoxia-responsive genes is the angiogenic stimulus vascular endothelial growth factor, expression of which is dramatically upregulated by hypoxia in many cells types, including RA synovial membrane cells. This leads to an apparent paradox, with the abundant synovial vasculature (which might be expected to restore oxygen levels to normal) occurring nonetheless together with regions of synovial hypoxia. It has been shown in a number of studies that vascular endothelial growth factor blockade is effective in animal models of arthritis; these findings suggest that hypoxia may activate the angiogenic cascade, thereby contributing to RA development. Recent data also suggest that, as well as activating angiogenesis, hypoxia may regulate many other features that are important in RA, such as cell trafficking and matrix degradation. An understanding of the biology of the HIF transcription family may eventually lead to the development of therapies that are aimed at interfering with this key signalling pathway, and hence to modulation of hypoxia-dependent pathologies such as RA.