Joint inflammation and cartilage destruction may occur uncoupled

IL-27 attenuates IL-23 mediated inflammatory arthritis

Interleukin 27 has both pro-inflammatory and anti-inflammatory properties in autoimmunity. The anti-inflammatory effects of IL-27 are linked with inhibition of Th17 differentiation but the IL-27 effect on myeloid cells is less studied. Herein we demonstrate that IL-27 inhibits IL-23-induced inflammation associated not only with Th17 cells but also with myeloid cell infiltration in the joints and splenic myeloid populations of CD11b+ GR1+ and CD3-CD11b+CD11c-GR1- cells. The IL-27 anti-inflammatory response was associated with reduced levels of myeloid cells in the spleen and bone marrow. Overall, our data demonstrate that IL-27 has an immunosuppressive role that affects IL-23-dependent myelopoiesis in the bone marrow and its progression to inflammatory arthritis and plays a crucial role in controlling IL-23 driven joint inflammation by negatively regulating the expansion of myeloid cell subsets.

Occurrence of familial Mediterranean fever in haemophilia patients

INTRODUCTION

This is the first study of simultaneous occurrences of Familial Mediterranean Fever (FMF) in patients with haemophilia.

AIM

The aim was to investigate the frequency and clinical characteristics of FMF in patients with severe haemophilia.

METHODS

Our study included 30 patients with severe haemophilia (26 haemophilia A and four haemophilia B). All 30 patients are screened for MEFV genotypes in FMF according to the new Eurofever/PRINTO diagnostic criteria. All cohorts were genetically tested for FMF and thrombophilia.

RESULTS

Eight (26%) of 30 haemophilic patients were diagnosed with FMF. Six different heterozygous FMF mutations including M694V (n = 2), E148Q (n = 2), V726A(n = 1), P369S (n = 1), E148Q/K695R (n = 1) and E148Q/M694I (n = 1) were identified. Seven had haemophilia A and only one had haemophilia B. Four (50%) patients had a positive family history and three of them had extraarticular findings specific to FMF. Only one haemophilia B patient received colchicine. Target joints in the knee, ankle, and elbow were identified in three FMF patients. The number of target joints in eight patients with FMF was significantly lower than in twenty-two patients without FMF (p < .05). The annual number of suspected joint bleedings in FMF patients admitted to the hospital was 40; however, 15 (37.5%) were documented bleedings in ultrasounds. Hereditary thrombophilia was detected in seven of eight patients.

CONCLUSION

Our data indicate that screening for FMF may be useful in patients with haemophilia who develop arthritis without prominent bleeding and have a positive family history in many Mediterranean countries, including Turkey.

Epithelial-mesenchymal Transition of Peritoneal Mesothelial Cells Is Enhanced by M2c Macrophage Polarization

BACKGROUND

Peritoneal fibrosis (PF) can reduce the efficiency of peritoneal dialysis and eventually lead to ultrafiltration failure. Epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) is the start of PF. Macrophages are involved in the process. This study was to investigate the effect of macrophage polarization on EMT of PMCs.

METHODS

Monocyte-macrophage cells (THP-1) were treated to induce macrophage subsets (M1, M2a, M2c). The inducing was assessed by detecting protein and mRNA expression of cytokines using ELISA and RT-PCR. Subsequently, PMCs were co-cultured with M1, M2a and M2c, respectively, in Transwell chambers for 48 h and then expressions of E-cadherin and α-SMA were determined in PMCs. The PMCs that were not co-cultured with macrophages served as control PMCs. One-way ANOVA and SNK-q test were used to conduct statistics and P < .05 as significant.

RESULTS

Detection of the cytokines, including IL-6, IL-10, IL-12, TGF-β1, CCL17 and CXCL13, verified that the inducting of macrophage subtypes was successful. Compared to control, E-cadherin protein expression was significantly decreased and α-SMA protein expression increased in M1-treated PMCs (P < .05); M2a-treated PMCs had an increased gene expression of α-SMA (P < .05); E-cadherin protein and gene expression were decreased and α-SMA protein and gene expression increased significantly in M2c-treated PMCs (P < .05 or P < .01).

CONCLUSIONS

EMT of PMCs is enhanced by M2c macrophage polarization; meanwhile, M1 and M2a polarization may have the effect to some extent, but not as definite as M2c.

Comparative Expression Analyses of Pro- versus Anti-Inflammatory Mediators within Synovium of Patients with Joint Trauma, Osteoarthritis, and Rheumatoid Arthritis

Synovial injury and healing are complex processes including catabolic effects by proinflammatory cytokines and anabolic processes by anti-inflammatory mediators. Here we examined the expression of pro- versus anti-inflammatory mediators in synovium of patients with diagnostic arthroscopy (control), joint trauma (JT), osteoarthritis (OA), and rheumatoid arthritis (RA). Synovial samples from these patients were subjected to RT-PCR and double immunofluorescence confocal microscopy of pro- and anti-inflammatory mediators as well as immune cell markers. Interestingly, pro- and anti-inflammatory mediators were expressed predominantly in granulocytes in patients with JT and in macrophages, lymphocytes, and plasma cells in patients with OA and RA. Interestingly, parallel to the severity of inflammation, proinflammatory mediators IL-1β, TNF-α, and 5-LOX specific mRNA as well as immunoreactive (IR) cells were significantly more abundant in patients with RA and JT than in those with OA. However, anti-inflammatory mediators 15-LOX, FPR2, and IL-10 specific mRNA as well as IR cells were significantly more abundant in patients with OA than in those with JT and RA. These findings show that upregulation of proinflammatory mediators contributes to the predominantly catabolic inflammatory process in JT and RA synovium, whereas upregulation of anabolic anti-inflammatory mediators counteracts inflammation resulting in the inferior inflammatory process in OA synovium.

Anti-TNFα alters the natural history of experimental Crohn's disease in rats when begun early, but not late, in disease

Anti-TNFα therapy decreases inflammation in Crohn's disease (CD). However, its ability to decrease fibrosis and alter the natural history of CD is not established. Anti-TNF-α prevents inflammation and fibrosis in the peptidoglycan-polysaccharide (PG-PS) model of CD. Here we studied anti-TNF-α in a treatment paradigm. PG-PS or human serum albumin (HSA; control) was injected into bowel wall of anesthetized Lewis rats at laparotomy. Mouse anti-mouse TNF-α or vehicle treatment was begun day (d)1, d7, or d14 postlaparotomy. Rats were euthanized d21-23. Gross abdominal and histologic findings were scored. Cecal levels of relevant mRNAs were measured by quantitative real-time PCR. There was a stepwise loss of responsiveness when anti-TNFα was begun on d7 and d14 compared with d1 that was seen in the percent decrease in the median gross abdominal score and histologic inflammation score in PG-PS-injected rats [as %decrease; gross abdominal score: d1 = 75% (P = 0.003), d7 = 57% (P = 0.18), d14 = no change (P = 0.99); histologic inflammation: d1 = 57% (P = 0.006), d7 = 50% (P = 0.019), d14 = no change (P = 0.99)]. This was also reflected in changes in IL-1β, IL-6, TNF-α, IGF-I, TGF-β1, procollagen I, and procollagen III mRNAs that were decreased or trended downward in PG-PS-injected animals given anti-TNF-α beginning d1 or d7 compared with vehicle-treated rats; there was no effect if anti-TNF-α was begun d14. This change in responsiveness to anti-TNFα therapy was coincident with a major shift in the cytokine milieu observed on d14 in the PG-PS injected rats (vehicle treated). Our data are consistent with the clinical observation that improved outcomes occur when anti-TNF-α therapy is initiated early in the course of CD.

Interleukin-1 in Rheumatoid Arthritis: Its Inhibition by IL-1Ra and Anakinra

Objective:

To review the biology of interleukin-1 (IL-1) in the pathogenesis of rheumatoid arthritis (RA), as well as the biology of its natural inhibitor, IL receptor antagonist (IL-1Ra), and the clinical efficacy and safety of the recombinant form, anakinra.

Data Sources:

A MEDLINE search (1966–January 2007) of English-language articles was conducted using the key words anakinra, arthritis, clinical trial, interleukin-1 receptor antagonist, and Kineret.

Study Selection and Data Extraction:

Over 79 research articles and literature reviews were used to compile a discussion of the biology of IL-1 and IL-1Ra. Ten of these articles were selected to discuss the clinical safety and efficacy of anakinra.

Data Synthesis:

In RA, IL-1 primarily acts locally to mediate erosion of cartilage and bone. IL-1Ra serves to modulate its activity through competitive inhibition of cellular receptors. Administration of anakinra to animals with experimental arthritis reduced inflammation and joint damage. In clinical trials, anakinra was reasonably well tolerated; however, injection site reactions were frequent and there was a slight increased risk of serious infection. Alone or in combination with methotrexate, anakinra significantly reduced the symptoms and clinical signs of RA at the American College of Rheumatology 20% response level. However, no additive benefit was observed following coadministration with etanercept, a soluble tumor necrosis factor antagonist, and anakinra had no beneficial effect in patients that failed treatment with etanercept.

Conclusions:

Laboratory studies have indicated that IL-1 is primarily responsible for cartilage destruction and bone erosion in RA. The selective inhibition of IL-1 through administration of anakinra may offer symptomatic relief of RA in some patients.

Imiquimod: the biochemical mechanisms of immunomodulatory and anti-inflammatory activity

Imidazoquinolins represent a new group of compounds that recently entered into clinical practice as anti-tumor and anti-viral immune modulators. They are low molecular weight synthetic guanosine-like molecules. Although imiquimod, the most widely used imidazoquinolin, is recommended for the treatment of several forms of skin cancer and papillomas, the molecular mechanisms of its action are not fully understood. In particular, imiquimod has been characterized as a specific agonist of Toll-like receptor 7 (TLR7) and is widely used in this capacity in a large number of experimental studies and clinical trials. However, detailed analysis of the published data with the use of imiquimod, suggests that its biological activity can not be explained only by interaction with TLR7. There are indications of a direct interaction of imiquimod with adenosine receptors and other molecules that regulate the synthesis of cyclic adenosine monophosphate. A detailed understanding of the biochemical basis of imiquimod immunomodulating and antitumor effect will increase its clinical effectiveness and accelerate the development of new drugs with similar but improved medical properties. This review summarizes the published data concerning the effects of imiquimod on a variety of intracellular biochemical processes and signaling pathways.

BMP-7 inhibits cartilage degeneration through suppression of inflammation in rat zymosan-induced arthritis

Bone morphogenetic protein-7 (BMP-7) regulates cartilage metabolism and promotes matrix synthesis. However, the effect of BMP-7 on inflammatory arthritis remains unknown. We investigated the effect and mechanism of exogenous BMP-7 on cartilage and synovium in vivo in rat zymosan-induced arthritis. Zymosan was injected into the left knees of Wistar rats. Phosphate-buffered saline or BMP-7 at 10, 100, or 1000 ng per joint was injected into the left knee every 2 days. Normal joints acted as normal controls. The knee joints were analyzed histologically and immunohistologically at 14 days. Joint swelling was evaluated by measuring the transverse diameter of the knee joints. Synovial lysates were collected, and the concentrations of interleukin-1β (IL-1β), IL-6, and IL-10 were measured by enzyme-linked immunosorbent assay. Intra-articular injection of zymosan resulted in acute inflammation and was followed by cartilage degeneration. Local administrations of BMP-7 inhibited this loss of cartilage matrix in a dose-dependent manner. Immunohistochemical analysis demonstrated enhanced type II collagen levels in cartilage and enhanced BMP-7 levels in cartilage and synovium after exogenous BMP-7 treatment. Joint swelling and cell infiltration into synovium were significantly reduced by BMP-7 injections. Administration of BMP-7 decreased IL-1β production significantly and increased IL-10 production in the synovium. Thus, intra-articular injections of BMP-7 had a protective effect on cartilage degeneration in the inflammatory arthritis model by enhancing levels of BMP-7 in cartilage and suppressing the production of IL-1β in synovium.

Rodent preclinical models for developing novel antiarthritic molecules: comparative biology and preferred methods for evaluating efficacy

Rodent models of immune-mediated arthritis (RMIA) are the conventional approach to evaluating mechanisms of inflammatory joint disease and the comparative efficacy of antiarthritic agents. Rat adjuvant-induced (AIA), collagen-induced (CIA), and streptococcal cell wall-induced (SCW) arthritides are preferred models of the joint pathology that occurs in human rheumatoid arthritis (RA). Lesions of AIA are most severe and consistent; structural and immunological changes of CIA best resemble RA. Lesion extent and severity in RMIA depends on experimental methodology (inciting agent, adjuvant, etc.) and individual physiologic parameters (age, genetics, hormonal status, etc.). The effectiveness of antiarthritic molecules varies with the agent, therapeutic regimen, and choice of RMIA. All RMIA are driven by overactivity of proinflammatory pathways, but the dominant molecules differ among the models. Hence, as with the human clinical experience, the efficacy of various antiarthritic molecules differs among RMIA, especially when the agent is a specific cytokine inhibitor.

Adjuvants and delivery systems in veterinary vaccinology: current state and future developments

Modern adjuvants should induce strong and balanced immune responses, and it is often desirable to induce specific types of immunity. As an example, efficient Th1-immunity-inducing adjuvants are highly in demand. Such adjuvants promote good cell-mediated immunity against subunit vaccines that have low immunogenicity themselves. The development of such adjuvants may take advantage of the increased knowledge of the molecular mechanisms and factors controlling these responses. However, knowledge of such molecular details of immune mechanisms is relatively scarce for species other than humans and laboratory rodents, and in addition, there are special considerations pertaining to the use of adjuvants in veterinary animals, such as production and companion animals. With a focus on veterinary animals, this review highlights a number of approaches being pursued, including cytokines, CpG oligonucleotides, microparticles and liposomes.

Expression of aquaporin 1 (AQP1) in human synovitis

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by synovial proliferation (synovitis), articular cartilage and subchondral bone degradation as well as joint swelling. Joint swelling and edema often accompany pannus formation and chronic joint inflammation in RA. We have recently shown that human chondrocytes and synoviocytes express aquaporin 1 (AQP1) water channels and that AQP1 is upregulated in RA cartilage. Clinical evidence suggests that joint swelling and edema accompany the chronic inflammation observed in synovial joints of RA patients. Therefore we hypothesized that AQP1 water channels may be involved in joint swelling and synovial edema formation. To test this hypothesis, we performed immunostaining of normal and human synovitis tissue microarrays (TMAs) to investigate whether the expression of AQP1 water channels is altered in the synovium in synovitis. Immunohistochemistry revealed that AQP1 is expressed in synovial micro-vessels and synoviocytes from normal joints (n=20 normal subjects). Semi-quantitative histomorphometric analysis of AQP1 expression in the TMAs revealed upregulation of the membrane protein in the synovium derived from RA (n=10) and psoriatic arthritis (n=8) patients. These results indicate a potential role for synovial AQP1 and other aquaporins in joint swelling and the vasogenic edema fluid formation and hydrarthrosis associated with synovial inflammation. Future experiments will need to determine whether the expression of other aquaporins is altered in synovitis.

Local interleukin-1-driven joint pathology is dependent on toll-like receptor 4 activation

Toll-like receptors (TLRs) may contribute to the pathogenesis of chronic inflammatory destructive diseases through the recognition of endogenous ligands produced on either inflammation or degeneration of the extracellular matrix. The presence of endogenous TLR agonists has been reported in rheumatoid joints. In the present study, we investigated the significance of TLR2 and TLR4 activation by locally- produced endogenous ligands in the severity of joint inflammation and destruction. Local joint pathology independent of systemic immune activation was induced by overexpression of interleukin (IL)-1 and TNF in naive joints using adenoviral gene transfer. Here, we report that at certain doses, IL-1-induced local joint inflammation, cartilage proteoglycan depletion, and bone erosion are dependent on TLR4 activation, whereas TLR2 activation is not significantly involved. In comparison, tumor necrosis factor alpha-driven joint pathology seemed to be less dependent on TLR2 and TLR4. The severity of IL-1-induced bone erosion and irreversible cartilage destruction was markedly reduced in TLR4(-/-) mice, even though the degree of inflammation was similar, suggesting uncoupled processes. Furthermore, the expression of cathepsin K, a marker for osteoclast activity, induced by IL-1beta was dependent on TLR4. Overexpression of IL-1beta in the joint as well as ex vivo IL-1 stimulation of patellae provoked the release of endogenous TLR4 agonists capable of inducing TLR4-mediated cytokine production. These data emphasize the potential relevance of TLR4 activation in rheumatoid arthritis, particularly with respect to IL-1-mediated joint pathology.

Superior protective immunity against murine listeriosis by combined vaccination with CpG DNA and recombinant Salmonella enterica serovar typhimurium

Preexisting antivector immunity can severely compromise the ability of Salmonella enterica serovar Typhimurium live vaccines to induce protective CD8 T-cell frequencies after type III secretion system-mediated heterologous protein translocation in orally immunized mice. To circumvent this problem, we injected CpG DNA admixed to the immunodominant p60(217-225) peptide from Listeria monocytogenes subcutaneously into BALB/c mice and coadministered a p60-translocating Salmonella strain by the orogastric route. The distribution of tetramer-positive p60(217-225)-specific effector and memory CD8 T cells was analyzed by costaining of lymphocytes with CD62L and CD127. In contrast to the single oral application of recombinant Salmonella or single immunization with CpG and p60, in the spleens from mice immunized with a combination of both vaccine types a significantly higher level of p60-specific CD8 T cells with a predominance of the effector memory T-cell subset was detected. In vivo protection studies revealed that this CD8 T-cell population conferred sterile protective immunity against a lethal infection with L. monocytogenes. However, p60-specific central memory CD8 T cells induced by single vaccination with CpG and p60 were not able confer effective protection against rapidly replicating intracellular Listeria. In conclusion, we provide compelling evidence that the combination of Salmonella type III-mediated antigen delivery and CpG immunization is an attractive novel vaccination strategy to modulate CD8 differentiation patterns toward distinct antigen-specific T-cell subsets with favorable protective capacities.

Delivery strategies of melanoma vaccines: an overview

For many years, various cancer vaccines have been widely evaluated, however clinical responses remain rare. In this review, we attempt to address the question of which delivery strategies and platforms are feasible to produce clinical response and define the characteristics of the strategy that will induce long-lasting antitumor response. We limit our analysis and discussion to microparticles/nanoparticles, liposomes, heat-shock proteins, viral vectors and different types of adjuvants. This review aims to provide an overview of the specific characteristics, strengths and limitations of these delivery systems, focusing on their impacts on the development of melanoma vaccine. To date, only adoptive T-cell transfer has shown promising clinical outcomes compared to other treatments.

Enhancement of immunity and resistance in mice by pig IL-6 gene and CpG motifs encapsulated in chitosan nanoparticle

This study was conducted to explore the synergetic effect of a novel plasmid containing a porcine IL-6 gene and CpG motifs on immunity of mice in order to develop an effective adjuvant to boost resistance against infection. The synthetic oligodeoxynucleotide containing 11 CpG motifs was inserted into the reconstructed VR1020 plasmid containing the pig IL-6 gene (VRPIL6), designated VRIL6C, and then encapsulated in chitosan nanoparticles (CNP) prepared by ionic cross linkage, designated VRIL6C-CNP. The 3-week old mice were injected, respectively, with VRIL6C-CNP, VRIL6-CNP, CpG-CNP and VR1020-CNP to detect the changes of immunity. At 28 days post inoculation, the mice were challenged with virulent hemolytic serotype 2 Streptococcus to test their resistance against infection. The results showed that there was a significant increase in immunoglobulins and interleukins in mice receiving VRIL6C-CNP compared with the control groups, as well as an increase in the lymphocytes and monocytes in the inoculated mice, so that the immunity was remarkably improved in the VRIL6C-CNP group. The challenge provoked stronger immunity and protection against infection in the VRIL6C-CNP group than in the control mice that manifested severe symptoms and lesions. This suggests that VRIL6C-CNP could remarkably enhance the nonspecific immunity of mice, and facilitate the development of an effective immunopotentiator to promote the resistance of the animals against infection.

17beta-estradiol induces IL-1alpha gene expression in rheumatoid fibroblast-like synovial cells through estrogen receptor alpha (ERalpha) and augmentation of transcriptional activity of Sp1 by dissociating histone deacetylase 2 from ERalpha

Rheumatoid arthritis (RA) occurs four times more frequently in women than in men, although the mechanistic basis of the gender difference is unknown. RA is characterized by the overproliferation of synoviocytes producing proinflammatory cytokines such as IL-1, implicated in the pathogenesis of the disease. In this study we examined whether 17beta-estradiol (E2) induced IL-1alpha mRNA expression in the rheumatoid fibroblast-like cell line MH7A, as well as in primary synovial cells from RA patients, and investigated the underlying molecular mechanisms. E2 induced IL-1alpha mRNA expression in both cell types in an estrogen receptor-dependent manner. In MH7A cells ERalpha but not ERbeta mediated the effects of E2. Deletion and mutation analysis revealed that a GC-rich region within the IL-1alpha gene promoter was responsible for the response to E2. EMSAs showed that Sp1 and Sp3 bound to the GC-rich region and that the transcriptional activity of Sp1 was up-regulated by the treatment with E2. Sp1 and ERalpha interacted physically regardless of the presence of E2. Physical interaction was also observed between ERalpha and histone deacetylase 2 (HDAC2), and E2 induced the dissociation of HDAC2 from ERalpha. These results suggest that E2 induces the dissociation of corepressor HDAC2 from ERalpha, which leads to the augmentation of Sp1 transcriptional activity through the GC-rich region within the IL-1alpha gene promoter.

Serum macrophage inhibitory cytokine 1 in rheumatoid arthritis: a potential marker of erosive joint destruction

OBJECTIVE

The transforming growth factor beta superfamily member macrophage inhibitory cytokine 1 (MIC-1) is expressed upon macrophage activation, regulated by the p53 pathway, and linked to clinical events in atherosclerosis and cancer. Since rheumatoid arthritis (RA) shares similar etiopathologic mechanisms with the above diseases, we sought to determine the clinical utility of determining MIC-1 serum levels and MIC-1 genotype in the management of RA.

METHODS

Ninety-one RA patients were recruited. Serum was collected from 83 of these patients and synovial biopsy samples were collected from the remaining 8 patients. Of the 83 patients from whom serum was collected, 61 were treated on an outpatient basis (defined as having nonsevere disease), and 22 patients went on to undergo hemopoietic stem cell transplantation (HSCT) (defined as having severe disease).

RESULTS

Serum levels of MIC-1 were higher in RA patients and reflected disease severity independently of classic disease markers. MIC-1 was detected in rheumatoid synovial specimens, and allelic variation of MIC-1 was associated with earlier erosive disease and severe treatment-resistant chronic RA. Additionally, algorithms including serum and/or allelic variation in MIC-1 predicted response to HSCT, the presence of severe disease, and joint erosions.

CONCLUSION

Determination of serum levels of MIC-1 and MIC-1 genotype may be clinically useful in the management of RA as well as in selection of patients for HSCT, since they predict disease course and response to therapy. The data indicate a potential role for MIC-1 in RA pathogenesis. These results warrant larger prospective studies to fully delineate and confirm a role for MIC-1 genotyping and serum estimation in patient selection for HSCT and in the management of RA.

TNF-alpha is necessary for induction of coronary artery inflammation and aneurysm formation in an animal model of Kawasaki disease

Kawasaki disease is the most common cause of multisystem vasculitis in childhood. The resultant coronary artery lesions make Kawasaki disease the leading cause of acquired heart disease in children in the developed world. TNF-alpha is a pleiotropic inflammatory cytokine elevated during the acute phase of Kawasaki disease. In this study, we report rapid production of TNF-alpha in the peripheral immune system after disease induction in a murine model of Kawasaki disease. This immune response becomes site directed, with migration to the coronary arteries dependent on TNF-alpha-mediated events. Production of TNF-alpha in the heart is coincident with the presence of inflammatory infiltrate at the coronary arteries, which persists during development of aneurysms. More importantly, inflammation and elastin breakdown in the coronary vessels are completely eliminated in the absence of TNF-alpha effector functions. Mice treated with the TNF-alpha-blocking agent etanercept, as well as TNFRI knockout mice, are resistant to development of both coronary arteritis and coronary aneurysm formation. Taken together, TNF-alpha is necessary for the development of coronary artery lesions in an animal model of Kawasaki disease. These findings have important implications for potential new therapeutic interventions in children with Kawasaki disease.

The chrondoprotective actions of a natural product are associated with the activation of IGF-1 production by human chondrocytes despite the presence of IL-1beta

BACKGROUND

Cartilage loss is a hallmark of arthritis and follows activation of catabolic processes concomitant with a disruption of anabolic pathways like insulin-like growth factor 1 (IGF-1). We hypothesized that two natural products of South American origin, would limit cartilage degradation by respectively suppressing catabolism and activating local IGF-1 anabolic pathways. One extract, derived from cat's claw (Uncaria guianensis, vincaria), is a well-described inhibitor of NF-kappaB. The other extract, derived from the vegetable Lepidium meyenii (RNI 249), possessed an uncertain mechanism of action but with defined ethnomedical applications for fertility and vitality.

METHODS

Human cartilage samples were procured from surgical specimens with consent, and were evaluated either as explants or as primary chondrocytes prepared after enzymatic digestion of cartilage matrix. Assessments included IGF-1 gene expression, IGF-1 production (ELISA), cartilage matrix degradation and nitric oxide (NO) production, under basal conditions and in the presence of IL-1beta.

RESULTS

RNI 249 enhanced basal IGF-1 mRNA levels in human chondrocytes by 2.7 fold, an effect that was further enhanced to 3.8 fold by co-administration with vincaria. Enhanced basal IGF-1 production by RNI 249 alone and together with vincaria, was confirmed in both explants and in primary chondrocytes (P < 0.05). As expected, IL-1beta exposure completely silenced IGF-1 production by chondrocytes. However, in the presence of IL-1beta both RNI 249 and vincaria protected IGF-1 production in an additive manner (P < 0.01) with the combination restoring chondrocyte IGF-1 production to normal levels. Cartilage NO production was dramatically enhanced by IL-1beta. Both vincaria and RNI 249 partially attenuated NO production in an additive manner (p < 0.05). IL-1beta - induced degradation of cartilage matrix was quantified as glycosaminoglycan release. Individually RNI 249 or vincaria, prevented this catabolic action of IL-1beta.

CONCLUSION

The identification of agents that activate the autocrine production of IGF-1 in cartilage, even in the face of suppressive pro-inflammatory, catabolic cytokines like IL-1beta, represents a novel therapeutic approach to cartilage biology. Chondroprotection associated with prevention of the catabolic events and the potential for sustained anabolic activity with this natural product suggests that it holds significant promise in the treatment of debilitating joint diseases.

Decrease in expression of bone morphogenetic proteins 4 and 5 in synovial tissue of patients with osteoarthritis and rheumatoid arthritis

Bone morphogenetic proteins (BMPs) have been identified as important morphogens with pleiotropic functions in regulating the development, homeostasis and repair of various tissues. The aim of this study was to characterize the expression of BMPs in synovial tissues under normal and arthritic conditions. Synovial tissue from normal donors (ND) and from patients with osteoarthritis (OA) and rheumatoid arthritis (RA) were analyzed for BMP expression by using microarray hybridization. Differential expression of BMP-4 and BMP-5 was validated by semiquantitative RT-PCR, in situ hybridization and immunohistochemistry. Activity of arthritis was determined by routine parameters for systemic inflammation, by histological scoring of synovitis and by semiquantitative RT-PCR of IL-1β, TNF-α, stromelysin and collagenase I in synovial tissue. Expression of BMP-4 and BMP-5 mRNA was found to be significantly decreased in synovial tissue of patients with RA in comparison with ND by microarray analysis (p < 0.0083 and p < 0.0091). Validation by PCR confirmed these data in RA (p < 0.002) and also revealed a significant decrease in BMP-4 and BMP-5 expression in OA compared with ND (p < 0.015). Furthermore, histomorphological distribution of both morphogens as determined by in situ hybridization and immunohistochemistry showed a dominance in the lining layer of normal tissues, whereas chronically inflamed tissue from patients with RA revealed BMP expression mainly scattered across deeper layers. In OA, these changes were less pronounced with variable distribution of BMPs in the lining and sublining layer. BMP-4 and BMP-5 are expressed in normal synovial tissue and were found decreased in OA and RA. This may suggest a role of distinct BMPs in joint homeostasis that is disturbed in inflammatory and degenerative joint diseases. In comparison with previous reports, these data underline the complex impact of these factors on homeostasis and remodeling in joint physiology and pathology.

Transcription factor T-bet regulates inflammatory arthritis through its function in dendritic cells

The transcription factor T-bet (Tbx21) plays a major role in adaptive immunity and is required for optimal IFN-gamma production by DCs. Here we demonstrate an essential function for T-bet in DCs in controlling inflammatory arthritis. We show that collagen antibody-induced arthritis (CAIA), a model of human RA, is a bipartite disease characterized by an early innate immune system component intact in RAG2 mice and a later adaptive immune system phase. Mice lacking T-bet had markedly reduced joint inflammation at both early and late time points and RAG2T-bet double-deficient mice were essentially resistant to disease. Remarkably, adoptive transfer of T-bet-expressing DCs reconstituted inflammation in a T-bet deficient and T-bet/RAG2-deficient milieu. T-bet regulates the production of proinflammatory cytokine IL-1alpha and chemokines macrophage inflammatory protein-1alpha (MIP-1alpha) and thymus- and activation-related chemokine (TARC) by DCs. Further, T-bet expression in DCs is required for T helper cell activation. We conclude that T-bet plays a vital function in DCs that links innate and adaptive immunity to regulate inflammatory responses. T-bet provides an attractive new target for the development of novel therapeutics for inflammatory arthritis.

Punica granatum L. extract inhibits IL-1beta-induced expression of matrix metalloproteinases by inhibiting the activation of MAP kinases and NF-kappaB in human chondrocytes in vitro

Interleukin (IL)-1beta induces the expression of matrix metalloproteinases (MMPs) implicated in cartilage resorption and joint degradation in osteoarthritis (OA). Pomegranate fruit extract (PFE) was recently shown to exert anti-inflammatory effects in different disease models. However, no studies have been undertaken to investigate whether PFE constituents protect articular cartilage. In the present studies, OA chondrocytes or cartilage explants were pretreated with PFE and then stimulated with IL-1beta at different time points in vitro. The amounts of proteoglycan released were measured by a colorimetric assay. The expression of MMPs, phosphorylation of the inhibitor of kappaBalpha (IkappaBalpha) and mitogen-activated protein kinases (MAPKs) was determined by Western immunoblotting. Expression of mRNA was quantified by real-time PCR. MAPK enzyme activity was assayed by in vitro kinase assay. Activation of nuclear factor-kappaB (NF-kappaB) was determined by electrophoretic mobility shift assay. PFE inhibited the IL-1beta-induced proteoglycan breakdown in cartilage explants in vitro. At the cellular level, PFE (6.25-25 mg/L) inhibited the IL-1beta-induced expression of MMP-1, -3, and -13 protein in the medium (P < 0.05) and this was associated with the inhibition of mRNA expression. IL-1beta-induced phosphorylation of p38-MAPK, but not that of c-Jun-N-terminal kinase or extracellular regulated kinase, was most susceptible to inhibition by low doses of PFE, and the addition of PFE blocked the activity of p38-MAPK in a kinase activity assay. PFE also inhibited the IL-1beta-induced phosphorylation of IkappaBalpha and the DNA binding activity of the transcription factor NF-kappaB in OA chondrocytes. Taken together, these novel results indicate that PFE or compounds derived from it may inhibit cartilage degradation in OA and may also be a useful nutritive supplement for maintaining joint integrity and function.

The fibroblast-like synovial cell in rheumatoid arthritis: a key player in inflammation and joint destruction

Although multiple cell types are present in the rheumatoid joint, the fibroblast-like synovial cell (FLS) is among the most prominent. It is now appreciated that the FLS is not only space-filling, but is directly responsible for cartilage destruction, and also drives both inflammation and autoimmunity. In this article, we consider the normal role of the FLS in healthy joints, and review evidence that implicates the FLS as a central player in the propagation of rheumatoid arthritis.

Suppressive effect of Dai-bofu-to on collagen-induced arthritis

Dai-bofu-to (DBT) is a traditional Japanese herbal medicine (Kampo medicine) used for the treatment of rheumatoid arthritis (RA). In the present study, to establish the usefulness of DBT, we examined the effect of DBT on collagen-induced arthritis (CIA). DBT (1.72 g/kg/d) significantly reduced the severity of arthritis throughout the experiment and significantly delayed the onset of arthritis. The induction of CIA decreased T cells and increased B cells in popliteal lymph nodes close to the affected joints, while the treatment of CIA with DBT counteracted the changes in T and B cells. In pX transgenic mice as a spontaneously developed arthritis model, a decrease in T cells and increase in B cells in popliteal lymph nodes were observed, as compared to BALB/c mice, the littermates of pX transgenic mice. In contrast, DBT returned the cell number of T and B cells to the level of BALB/c mice. As osteoclastogenesis is regulated by some T cell cytokines and osteotropic factors, we examined the effect of DBT on the receptor activator of NF-kappa B (RANK), RANK ligand (RANKL), osteoprotegerin (OPG) and M-CSF mRNAs, which were induced by arthritis induction. Although DBT had no effect on RNAK or RANKL mRNA levels, DBT stimulated an increase in OPG mRNA levels and suppressed an increase in M-CSF mRNA level. These results suggest that DBT may possess an anti-osteoclastogenetic effect, which is brought by reducing the ratio of RANKL/OPG and by decreasing M-CSF mRNA levels. In conclusion, immunomodulatory and anti-osteoclastogenetic effects might be involved in the suppression of arthritis by DBT.

Tissue repair in rheumatoid arthritis: challenges and opportunities in the face of a systemic inflammatory disease

Rheumatoid arthritis (RA) is a systemic inflammatory disease that can elicit a variable disease course, can influence a variable number of joints, and can exhibit a variable response to treatment. All of these factors contribute to the degree and extent of damage to joint components, as well as the potential for repair of other injured joint tissues/components. Furthermore, some of the RA treatments/drugs themselves can influence repair and injury responses, as well as the outcome of surgical interventions for advanced disease. However, as treatments and interventions become more sophisticated and successful in patient populations, the opportunity to initiate the repair/replacement of the damaged joint tissues also becomes more of a reality. This review will address the current clinical findings in the literature, and then discuss the issues and opportunities to initiate repair of damaged or injured joint tissues in order to restore joint function. These include growth factors, gene therapy, and bioengineered tissues, alone or in combination to augment endogenous repair or replace tissue damaged beyond such repair capabilities.

Coinjection with CpG-containing immunostimulatory oligodeoxynucleotides reduces the pathogenicity of a live vaccine against cutaneous Leishmaniasis but maintains its potency and durability

The inoculation of live, nonattenuated Leishmania major to produce a lesion in a selected site that heals, referred to as leishmanization, is to date the only vaccine against leishmaniasis that has proven to be effective in humans. Its use has been restricted or abandoned entirely, however, due to safety concerns. In an attempt to develop a leishmanization protocol that minimizes pathology while maintaining long-term protection, live parasites were coinjected with CpG-containing immunostimulatory oligodeoxynucleotides (CpG ODNs) alone or in combination with whole-cell lysates of heat-killed L. major promastigotes bound to alum (ALM). C57BL/6 mice infected intradermally by using L. major plus CpG ODN with or without ALM developed few or no dermal lesions and showed an early containment of parasite growth, while mice infected with L. major with or without ALM developed sizable dermal lesions that required up to 10 weeks to heal. The CpG ODNs provoked a transient inflammation that included an early recruitment and accumulation of gamma interferon-producing CD4(+) lymphocytes in the site. Attenuation of the live vaccine did not compromise its ability to confer long-term immunity, as mice receiving L. major and CpG ODN plus ALM were totally protected against reinfection with L. major for up to 6 months. By comparison, the immunity elicited by two efficient nonlive vaccines began to wane by 6 months. Our results suggest that immune modulation using CpG ODNs might be a practical approach to improving the safety of a highly effective live vaccine that has already been widely applied.

Analysis of the cell infiltrate and expression of proinflammatory cytokines and matrix metalloproteinases in arthroscopic synovial biopsies: comparison with synovial samples from patients with end stage, destructive rheumatoid arthritis

BACKGROUND

Synovial tissue (ST) from end stage destructive rheumatoid arthritis (RA) and arthroscopic biopsies obtained during active inflammation might exhibit different characteristics.

OBJECTIVE

To define the cell infiltrate and the expression of proinflammatory cytokines, angiogenic factors, and matrix metalloproteinases (MMPs) in ST selected at arthroscopy compared with that from end stage RA.

METHODS

Synovial biopsy specimens were obtained from the actively inflamed knee joints of 13 patients with chronic RA by arthroscopy and compared with ST from 10 patients with end stage, destructive RA. Immunohistological analysis was performed to detect T cells, plasma cells, macrophages, fibroblast-like synoviocytes (FLS), and the expression of interleukin (IL)1beta, IL6, tumour necrosis factor alpha (TNFalpha), MMP-1, MMP-3, MMP-13, TIMP-1, and VEGF.

RESULTS

The expression of CD68+ macrophages was significantly higher in ST selected at arthroscopy than in samples obtained at surgery, both in the intimal lining layer and in the synovial sublining. The expression of CD3+ T cells also tended to be higher in arthroscopic samples. The expression of TNFalpha, IL6, MMP-1, MMP-3, MMP-13, TIMP-1, and VEGF was on average higher in ST obtained at arthroscopy. In contrast, the expression of IL1beta was on average higher in surgical samples.

CONCLUSION

Active arthritis activity is associated with increased cell infiltration, expression of proinflammatory cytokines, MMPs, and angiogenic growth factors in synovial biopsy samples selected at arthroscopy. Increased expression of IL1beta in the synovium of patients with destructive RA requiring joint replacement may well reflect the important role of IL1beta in cartilage and bone destruction.

IL-17 promotes bone erosion in murine collagen-induced arthritis through loss of the receptor activator of NF-kappa B ligand/osteoprotegerin balance

IL-17 is a T cell-derived proinflammatory cytokine in experimental arthritis and is a stimulator of osteoclastogenesis in vitro. In this study, we report the effects of IL-17 overexpression (AdIL-17) in the knee joint of type II collagen-immunized mice on bone erosion and synovial receptor activator of NF-kappa B ligand (RANKL)/receptor activator of NF-kappa B/osteoprotegerin (OPG) expression. Local IL-17 promoted osteoclastic bone destruction, which was accompanied with marked tartrate-resistant acid phosphatase activity at sites of bone erosion in cortical, subchondral, and trabecular bone. Accelerated expression of RANKL and its receptor, receptor activator of NF-kappa B, was found in the synovial infiltrate and at sites of focal bone erosion, using specific immunohistochemistry. Interestingly, AdIL-17 not only enhanced RANKL expression but also strongly up-regulated the RANKL/OPG ratio in the synovium. Comparison of arthritic mice from the AdIL-17 collagen-induced arthritis group with full-blown collagen-arthritic mice having similar clinical scores for joint inflammation revealed lower RANKL/OPG ratio and tartrate-resistant acid phosphatase activity in the latter group. Interestingly, systemic OPG treatment prevented joint damage induced by local AdIL-17 gene transfer in type II collagen-immunized mice. These findings suggest T cell IL-17 to be an important inducer of RANKL expression leading to loss of the RANKL/OPG balance, stimulating osteoclastogenesis and bone erosion in arthritis.

Cytokine traps: multi-component, high-affinity blockers of cytokine action

Cytokines can initiate and perpetuate human diseases, and are among the best-validated of therapeutic targets. Cytokines can be blocked by the use of soluble receptors; however, the use of this approach for cytokines such as interleukin (IL)-1, IL-4, IL-6 and IL-13 that use multi-component receptor systems is limited because monomeric soluble receptors generally exhibit low affinity or function as agonists. We describe here a generally applicable method to create very high-affinity blockers called 'cytokine traps' consisting of fusions between the constant region of IgG and the extracellular domains of two distinct cytokine receptor components involved in binding the cytokine. Traps potently block cytokines in vitro and in vivo and represent a substantial advance in creating novel therapeutic candidates for cytokine-driven diseases.

Molecular aspects of glucocorticoid hormone action in rheumatoid arthritis

Glucocorticoids (GC) are the most powerful anti-inflammatory drugs used in the treatment of autoimmune diseases such as rheumatoid arthritis. In addition, endogenous GC are involved in numerous physiological processes. Most of their effects are mediated by the glucocorticoid receptor (GR) via activation or repression of gene expression. Whereas activation requires DNA binding of the receptor, repression is mediated by protein-protein interactions with other transcription factors. In particular, most immunosuppressive and anti-inflammatory effects are exerted by an interaction of GR with the activating protein 1 (AP-1) and nuclear factor kappaB (NF-kappaB) families of transcription factors without DNA binding. Cytokines such as tumor necrosis factor alpha (TNF-alpha) and interleukin 1 (IL-1) activate the hypothalamus pituitary adrenal (HPA) axis, whereas GC inhibit IL-1 and TNF-alpha forming a cytokine-HPA axis feedback circuit. The high effectiveness of cytokine-antagonists blocking TNF-alpha or IL-1 in RA and the understanding of the precise molecular mechanisms of GC function will enhance our understanding of autoimmune diseases, such as RA, and could suggest new beneficial therapeutic approaches with fewer side-effects.

Use of immunostimulatory sequence-containing oligonucleotides as topical therapy for genital herpes simplex virus type 2 infection

Synthetic oligonucleotides containing CpG motifs in specific sequence contexts have been shown to induce potent immune responses. We have evaluated mucosal administration of two immunostimulatory sequence (ISS)-containing phosphorothioate-stabilized oligonucleotides for antiherpetic efficacy in animal models. The ISS oligonucleotides, suspended in phosphate-buffered saline, were tested in mouse and guinea pig vaginal models of herpes simplex virus type 2 (HSV-2) infection. For comparison, groups of untreated, non-ISS oligonucleotide-treated, and acyclovir-treated animals also were monitored. The results indicated that vaginal epithelial application of ISS (up to 6 h after viral inoculation) with mice lethally challenged with HSV-2 delayed disease onset and reduced the number of animals that developed signs of disease (P = 0.003). ISS application significantly increased survival rates over those of controls (P = 0.0014). The ISS also impacted an established infection in the guinea pig model of HSV-2 disease. A single administration of ISS (21 days after viral inoculation) significantly reduced the frequency and severity of HSV-2 lesions compared to results with non-ISS oligonucleotide-treated and untreated guinea pigs (P < 0.01). HSV-2 is shed from the vaginal cavity of the guinea pig in the absence of lesions, similar to the case with humans. As an additional indication of ISS efficacy, the magnitude of viral shedding also was significantly reduced in ISS-treated animals (P < 0.001). These effects appeared to be immunologically mediated, since ISS had no direct effect on HSV-2 replication in vitro using standard plaque assays. These data suggest that ISS may be useful in the treatment and control of genital herpes in humans.

Lifelong voluntary joint loading increases osteoarthritis in mice housing a deletion mutation in type II procollagen gene, and slightly also in non-transgenic mice

OBJECTIVES

To investigate the effects of voluntary running on the incidence and severity of osteoarthritis (OA) and associated changes in cartilage matrix and subchondral bone in a transgenic Del1 mouse model for OA.

METHODS

Del1 mice and their non-transgenic littermate controls were housed from the age of 5-6 weeks to 15 months in individual cages with running wheels. The running activity of each mouse was monitored for the entire 12 month period. Additional Del1 and control mice were housed in individual cages without running wheels. At the end of the experiment the severity of OA was evaluated by light microscopy, and the articular cartilage matrix changes by digital densitometry and quantitative polarised light microscopy.

RESULTS

Lifelong voluntary running increased the incidence and severity of OA significantly in Del1 mice (transgenic runners), and slightly also in non-transgenic runners. Severe OA changes increased from 39% in transgenic non-runners to 90% in transgenic runners (p=0.006) in lateral tibial condyles, and from 24% to 80% (p=0.013) in lateral femoral condyles, respectively. The proteoglycan content of articular cartilage was reduced in transgenic runners in comparison with transgenic non-runners (p=0.0167), but a similar effect was not seen in non-transgenic runners compared with non-transgenic non-runners. No attributable differences were seen in the collagen network of articular cartilage or in the subchondral bone between any of the groups.

CONCLUSION

The Del1 mutation has earlier been shown to disturb the assembly of the cartilage collagen network and thereby increase the incidence and severity of OA with age. In this study, voluntary running was shown to increase further cartilage damage in the lateral compartments of the knee. This suggests that articular cartilage in Del1 mice is less resistant to physical loading than in control mice. Despite severe OA lesions in the knee joint at the age of 15 months, Del1 mice continued to run voluntarily 2-3 km every night.

Lectin-like oxidized low-density lipoprotein receptor 1 mediates leukocyte infiltration and articular cartilage destruction in rat zymosan-induced arthritis

OBJECTIVE

The relationship between rheumatoid arthritis and atherosclerosis has been recognized for >20 years. This study aimed to elucidate the roles of oxidized low-density lipoprotein (ox-LDL; one of the main pathogenic factors of atherosclerosis) and its endothelial receptor, lectin-like ox-LDL receptor 1 (LOX-1), in arthritic joints using a rat zymosan-induced arthritis (ZIA) model.

METHODS

LOX-1 expression and ox-LDL accumulation in arthritic joints were detected by immunohistochemistry using specific mouse anti-LOX-1 and anti-ox-LDL monoclonal antibodies, respectively. To elucidate the effects of the expressed LOX-1 on arthritis, ZIA rats were treated with anti-LOX-1 antibody or normal mouse IgG. The severity of arthritis was analyzed by joint swelling. Cell infiltration, synovial hyperplasia, and proteoglycan losses were also determined by histologic scoring. Proinflammatory cytokine and nitrite levels in serum and joint fluid were also measured.

RESULTS

Immunohistochemical study of ZIA demonstrated LOX-1 expression on synovial endothelium and postcapillary venules at 6 hours after the induction of inflammation, with maximum expression detected at 24 hours. LOX-1 was also expressed weakly on both joint cartilage and synovium. Ox-LDL, a ligand of LOX-1, was also detected in articular chondrocytes. Administration of anti-LOX-1 antibody, which blocks LOX-1 activity, suppressed joint swelling (by 33.5%), leukocyte infiltration, and joint nitrite accumulation at 24 hours, as well as cartilage destruction at 7 days, compared with control rats.

CONCLUSION

LOX-1 induction in arthritic joints might play a role in promoting joint inflammation and cartilage destruction by mediating leukocyte infiltration into the arthritic joints of ZIA rats.

Reduction of CpG-induced arthritis by suppressive oligodeoxynucleotides

OBJECTIVE

Bacterial DNA contains immunostimulatory CpG motifs that cause inflammation when injected into the knee joints of normal mice. We examined whether synthetic oligodeoxynucleotides (ODN) that suppress CpG-induced immune responses prevent CpG-induced arthritis.

METHODS

CpG, suppressive, and/or control ODN were injected into the knees of BALB/c mice. Joint swelling and inflammation were evaluated by physical measurement, by histologic analysis of joint tissue, and by magnetic resonance imaging.

RESULTS

Immunostimulatory CpG DNA induced local arthritis, characterized by swelling of the knee joints, the presence of inflammatory cell infiltrates, the perivascular accumulation of mononuclear cells, and hyperplasia of the synovial lining. Administering suppressive (but not control) ODN reduced the manifestations and severity of arthritis up to 80%.

CONCLUSION

Suppressive ODN may be useful for the prevention or treatment of arthritis induced by bacterial DNA.

Autoantibodies against interleukin 1alpha in rheumatoid arthritis: association with long term radiographic outcome

OBJECTIVES

To investigate the possible association of interleukin 1alpha autoantibodies (IL1alpha aAb) with the long term course of joint erosion in patients with rheumatoid arthritis (RA).

METHODS

Serum samples from 176 patients with RA included in a prospective study over 30 years were analysed for IL1alpha aAb by binding to human [(125)I]IL1alpha. Erosions of 19 diarthrodial joints were radiographically scored by the Larsen method.

RESULTS

The relative risk (RR) of early IL1alpha aAb positive patients developing at least 30% of maximum radiographic joint destruction was significantly lower than for IL1alpha aAb negative patients, RR=0.29 (p=0.04). In rheumatoid factor positive patients RR was only 0.18 (p=0.02). Patients who seroconverted more than two years after the onset of RA showed the most aggressive development of joint erosion, with a relative risk of at least 40% of maximum radiographic joint destruction of 2.56 (p=0.048)

CONCLUSIONS

The progression of radiographic joint destruction in patients with RA is associated with, and perhaps modified by, circulating IL1alpha aAb, suggesting that IL1alpha or IL1alpha aAb, or both, have a role in the erosive processes. IL1alpha aAb appear to be of prognostic significance in RA.

Cytokine imbalance in non-immunological chronic disease

Over the last decade, cytokine imbalances have been associated with a plethora of diseases. While the Th(1)/Th(2) paradigm is widely used to explain the pathogenesis of immunological diseases, the role of cytokine imbalances for non-immunological diseases is still incompletely defined. The major obstacle here is to assess the extent to which non-immunological diseases are influenced by inflammation. Non-immunological diseases cover the whole spectrum from those triggered by infection-as may be the case for Alzheimer's disease-to those where the immune system has no apparent impact at all. Examples of the latter are bone diseases, including post-menopausal osteoporosis and skeletal malformations. In between there are diseases such as intrinsic asthma and osteoarthritis where the impact of the immune system is unclear. Thus far, imbalances affecting tumour necrosis factor (TNF)-alpha and members of the interleukin (IL)-1 and the TGF superfamily have been found in association with all of these diseases. We speculate here that cytokine imbalance will be found in additional diseases and touch on the role in phylogeny of cytokines outside the immune system.

CpG motifs in bacterial DNA and their immune effects

Unmethylated CpG motifs are prevalent in bacterial but not vertebrate genomic DNAs. Oligodeoxynucleotides (ODN) containing CpG motifs activate host defense mechanisms leading to innate and acquired immune responses. The recognition of CpG motifs requires Toll-like receptor (TLR) 9, which triggers alterations in cellular redox balance and the induction of cell signaling pathways including the mitogen activated protein kinases (MAPKs) and NF kappa B. Cells that express TLR-9, which include plasmacytoid dendritic cells (PDCs) and B cells, produce Th1-like proinflammatory cytokines, interferons, and chemokines. Certain CpG motifs (CpG-A) are especially potent at activating NK cells and inducing IFN-alpha production by PDCs, while other motifs (CpG-B) are especially potent B cell activators. CpG-induced activation of innate immunity protects against lethal challenge with a wide variety of pathogens, and has therapeutic activity in murine models of cancer and allergy. CpG ODN also enhance the development of acquired immune responses for prophylactic and therapeutic vaccination.

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Cytokines in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic disease characterized by synovial inflammation that leads to the destruction of cartilage and bone. In the last decade, there was a lot of successful research in the field of cytokine expression and regulation. It has become clear that pro- and anti-inflammatory cytokines, derived predominantely from cells of macrophage lineage, play a major role in the initiation and perpetuation of the chronic inflammatory process in the RA synovial membrane. Monokines are abundant in rheumatoid synovial tissue, whereas low amounts of lymphokines are found. The involvement of pro-inflammatory cytokines, particularly interleukin (IL)-1 and tumor necrosis factor-alpha, in the pathogenesis of RA is well accepted. Recent data provide evidence that the pro-inflammatory cytokine IL-18 plays a crucial role in the development and sustenance of inflammatory joint diseases. There also appears to be a compensatory anti-inflammatory response in RA synovial membrane. It has become clear in the last few years that T cell-derived cytokines expressed preferentially by Th1 cells contribute to joint destruction and inflammation in RA. However, products from Th2 cells may be protective.

Recent advances in TGF-beta effects on chondrocyte metabolism. Potential therapeutic roles of TGF-beta in cartilage disorders

Novel approaches to treat osteoarthritis are required and progress in understanding the biology of cartilage disorders has led to the use of genes whose products stimulate cartilage repair or inhibit breakdown of the cartilaginous matrix. Among them, transforming growth factor-beta (TGF-beta) plays a significant role in promoting chondrocyte anabolism in vitro (enhancing matrix production, cell proliferation, osteochondrogenic differentiation) and in vivo (short-term intra-articular injections lead to increased bone formation and subsequent cartilage formation, beneficial effects on osteochondrogenesis). In vivo induction of the expression of TGF-beta and the use of gene transfer may provide a new approach for treatment of osteoarthritic lesions.

Catechins from green tea (Camellia sinensis) inhibit bovine and human cartilage proteoglycan and type II collagen degradation in vitro

Polyphenolic compounds from green tea have been shown to reduce inflammation in a murine model of inflammatory arthritis, but no studies have been undertaken to investigate whether these compounds are protective to joint tissues. We therefore investigated the effects of catechins found in green tea on cartilage extracellular matrix components using in vitro model systems. Bovine nasal and metacarpophalangeal cartilage as well as human nondiseased, osteoarthritic and rheumatoid cartilage were cultured with and without reagents known to accelerate cartilage matrix breakdown. Individual catechins were added to the cultures and the amount of released proteoglycan and type II collagen was measured by metachromatic assay and inhibition ELISA, respectively. Possible nonspecific or toxic effects of the catechins were assessed by lactate output and proteoglycan synthesis. Catechins, particularly those containing a gallate ester, were effective at micromolar concentrations at inhibiting proteoglycan and type II collagen breakdown. No toxic effects of the catechins were evident. We conclude that some green tea catechins are chondroprotective and that consumption of green tea may be prophylactic for arthritis and may benefit the arthritis patient by reducing inflammation and slowing cartilage breakdown. Further studies will be required to determine whether these compounds access the joint space in sufficient concentration and in a form capable of providing efficacy in vivo.

Treatment of recalcitrant psoriatic arthritis with anti-tumor necrosis factor-alpha antibody

Currently available treatments for psoriatic arthritis are either not completely effective or toxic in some patients. As tumour necrosis factor (TNF)-alpha is involved in both the joint and skin involvement in psoriatic arthritis, blockade of TNF-alpha seems a reliable way to treat patients with this disease. We report two patients with progressive recalcitrant psoriatic arthritis treated with low-dose methotrexate (7.5 mg, once per week) in combination with intravenous chimeric monoclonal anti-TNF-alpha antibody (infliximab, 3 mg/kg body weight). Both showed a dramatic and rapid response in the reduction of pain, followed by improvement of laboratory and clinical signs of joint inflammation. Skin disease also responds after a short delay. The observation shows that infliximab is effective and well tolerated in patients with recalcitrant progressive psoriatic arthritis. Different kinetics of symptom release during treatment suggest a variable role for TNF-alpha in disease pathways of pain, joint inflammation and skin involvement.

Cytokine inhibitors in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is an immune-mediated disease characterised by articular inflammation and subsequent tissue damage leading to severe disability and increased mortality. A variety of cytokines are produced locally in the rheumatoid joints. Numerous studies have demonstrated that IL-1 and TNF-alpha, two prototypic pro-inflammatory cytokines, play an important role in the mechanisms involved in synovial inflammation and in progressive joint destruction. Indeed, the administration of TNF-alpha and IL-1 inhibitors in patients with RA led to a dramatic improvement of clinical and biological signs of inflammation and a reduction of radiological signs of bone erosion and cartilage destruction. However, despite these encouraging results, a significant percentage of patients do not respond to these agents, suggesting that other mediators are also involved in the pathophysiology of arthritis. This review describes the results of clinical trials with TNF-alpha inhibitors and a specific IL-1 inhibitor (IL-1 receptor antagonist [IL-1Ra]). In addition, other therapeutic strategies are also discussed.

Prognostic use of human leukocyte antigen genotyping for rheumatoid arthritis susceptibility, disease course, and clinical stratification

HLA markers of the class II region are important for determination of the predisposition to RA, clinical manifestations, and rate of progression of joint destruction in this autoimmune disease. Furthermore, evidence emerges indicating that HLA markers also have an impact on treatment outcome in RA. Currently, several immunopathogenetic models of HLA-dependent influences in RA are under debate. These models insufficiently explain the graded influence of HLA-DR and HLA-DQ on manifestation and joint destruction, however. Currently, there is not enough evidence to unequivocally identify a primary susceptibility locus or to pinpoint the HLA-dependent mechanism in RA. Overall, the influence of HLA class II markers on disease susceptibility is rather restricted, and, in turn, their utility in establishing the diagnosis of RA is of limited use. Although relative risks are higher for the association of particular genotypes with extra-articular forms of RA, HLA genotyping may not contribute to prognostication in individual patients but may aid in disease stratification. In contrast, HLA genotyping in early RA, particularly when combined with the determination of RFs and determination of the presence of bony erosions, is of value to identify patients at risk for poor outcome. In turn, these patients may benefit from early aggressive therapy, and HLA genotyping should be useful to aid in risk stratification in patients and thus helpful for the choice of treatment. Lastly, disease and risk stratification based on HLA markers along with the elucidation of HLA-dependent mechanisms may facilitate the development of specific immunotherapy modalities.