Autoimmunity: red line to arthritis.
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Biomedical subjects
Publications and source records attributed to A Tarkowski.
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OBJECTIVE: To analyse the inflammatory mediators, including monocyte chemoattractant protein-1 (MCP-1), in blood samples donated years before onset of rheumatoid arthritis. Previously, it has been shown in these individuals that antibodies against cyclic citrullinated peptide (anti-CCP) detectable years before the onset of symptoms have a high predictive value for development of rheumatoid arthritis. METHODS: A nested case-control study was performed: patients with rheumatoid arthritis were identified from among blood donors antedating onset by a median of three years (pre-patients, n = 92); four matched controls were selected randomly for each pre-patient. Plasma were analysed for secretory phospholipase A2 (sPLA2) and MCP-1 using ELISA, for high-sensitivity C reactive protein (hsCRP) using the chemiluminescence method and for interleukin-6 using a sensitive bioassay. RESULTS: When the results were stratified for the presence of anti-CCP antibodies and immunoglobulin M-rheumatoid factor (IgM-RF), only MCP-1 levels were found to be significantly raised in patients with anti-CCP and IgM-RF compared with controls. CONCLUSION: Levels of MCP-1 were significantly increased in the plasma of patients having anti-CCP antibodies or IgM-RF and who later developed rheumatoid arthritis. These findings indicate up regulation of chemotactic activity for leucocytes before the development of rheumatoid arthritis.
B cells are in analogy with T cells capable of expressing functional IL-2 receptors. IL-2R alpha-chain (CD25) positive T cells have been studied in detail but not much is known about CD25 positive B cells. The aim of this study was to examine the phenotypic properties of the CD25 expressing B cells collected from different lymphoid organs in mice. Samples were stained for various cell surface markers and analysed using flow cytometry. We found that approximately 49% of B cells in bone marrow, 16% in peritoneal cavity, 2% in spleen and 1% in lymph nodes express CD25. In contrast, CD25 expressing B cells were not found in the blood or in Peyer's patches. Phenotypic characterization showed that CD25+ B cells in spleen, lymph nodes and peritoneal cavity have higher expression of AA4.1, CD5, CD69, CD80, CD86, CD122, CD132, IgA, IgG and IgM on their surface in comparison with CD25- B cells. In contrast, expression of IgD and IA-IE was lower on CD25+ B cells in spleen and lymph nodes. In bone marrow, the expression of CD5, CD80, CD86, CD122, CD132, IgA, IgD and IgM was lower, while the expression of AA4.1, IgG and IA-IE was increased on CD25+ B cells compared with CD25- B cells. In conclusion, our results indicate that B cells expressing CD25 are phenotypically distinctly different from those that are CD25 negative. Our findings suggest that CD25+ B cells are more prone to efficient antigen presentation and display a more mature phenotype.
BACKGROUND: Several proatherothrombotic conditions are associated with enhanced levels of circulating proinflammatory cytokines, which are believed to impair endothelial fibrinolytic capacity. OBJECTIVE: This study aims at investigating how tumor necrosis factor (TNF)-alpha regulates endothelial gene expression of the key fibrinolytic enzyme tissue-type plasminogen activator (t-PA). METHODS: Cultured human umbilical vein endothelial cells were pretreated with selective inhibitors of the three major inflammatory signaling pathways activated by TNF-alpha; the nuclear factor kappa-B (NF-kappaB), the p38 mitogen-activated protein kinase (p38 MAPK), and the c-jun N-terminal kinase (JNK) pathways. Following TNF-alpha stimulation, effects on t-PA gene expression were evaluated with real-time reverse transcriptase polymerase chain reaction and interactions of nuclear proteins with potential gene regulatory elements were studied with electrophoretic mobility shift assays. RESULTS: Approximately 50% suppression of t-PA gene expression was observed after prolonged stimulation with TNF-alpha (> or =24 h). The repression was shown to be preferentially dependent on NF-kappaB activation, but also on p38 MAPK signaling. Further, we provide evidence for a TNF-alpha induced binding of NF-kappaB to the recently described kappaB site in the t-PA gene and of cyclic adenosine monophosphate response element binding protein (CREB) to the t-PA CRE-like site. CONCLUSIONS: We conclude that TNF-alpha impairs fibrinolytic capacity in vascular endothelial cells by a NF-kappaB and p38 MAPK-dependent suppression of t-PA. This mechanism sheds a light on how inflammation contributes to the pathogenesis of cardiovascular diseases.
OBJECTIVE AND DESIGN: Riboflavin, also known as vitamin B2, is a micronutrient with a key role in maintaining human health. It has also been shown to enhance host resistance to bacterial infections in mice. The aim of this study was to assess the role of vitamin B2 treatment in inflammatory conditions. SUBJECTS AND METHODS: Three models of inflammatory states were assessed. One of them encompasses neutrophil mediated but T cell/macrophage independent cutaneous inflammation. Another one is delayed type hypersensitivity reaction (DTH), a T cell/macrophage dependent but neutrophil independent inflammatory response. The third one is collagen- induced arthritis, having components from both of the above described reactions. Mice were treated with vitamin B2, administered by peritoneal injections, throughout the course of the experiments. RESULTS: The granulocyte dependent reaction to olive oil was significantly reduced in vitamin B2 treated mice. In contrast, DTH reactivity and collagen II arthritis were not affected by the treatment. CONCLUSION: Riboflavin administration affects neutrophil migration but does not alter acquired immune responsiveness.
OBJECTIVE: Clinical cartilage repair with transplantation of cultured chondrocytes, the first described technique introduced in 1994, includes a periosteal membrane but today cells are also implanted without the periosteal combination. The aim of this study was to see if the periosteum had more than a biomechanical function and if the periosteum had a biological effect on the seeded cells tested in an agarose system in which the clonal growth in agarose and the external growth stimulation could be analysed. METHODS: Four different experiments were used to study the growth of human chondrocytes in agarose and the periosteal influence. Human chondrocytes were isolated and transferred to either primary or secondary agarose culture. After 4 weeks, the total number of clones >50 microm was counted. Cocultures of chondrocytes and periosteal tissue, cultures of chondrocytes with conditioned medium from chondrocytes, periosteal cells and fibroblast were used to study a potential stimulatory effect on growth and different cytokines and growth factors were analysed. RESULTS: It was found that the human chondrocytes had different growth properties in agarose with the formation of four different types of clones: a homogenous clone without matrix production, a homogenous clone with matrix production, a differentiated clone with matrix production and finally a differentiated clone without matrix production. The periosteum exerted a paracrine effect on cultured chondrocytes in agarose resulting in a higher degree of cloning. The chondrocytes produced significant amounts of interleukin (IL)-6, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor (TGF)-beta. The periosteum produced significant amounts of IL-6, IL-8 and TGF-beta. Cocultures of chondrocytes and periosteum demonstrated a potentiation of IL-6 and IL-8 release but not of TGF-beta and GM-CSF. CONCLUSION: Articular chondrocytes are able to form clones of different properties in agarose and the periosteum has a capacity of stimulating chondrocyte clonal growth and differentiation and secretes significant amounts of IL-6, IL-8, GM-CSF and TGF-beta. It may be that the repair of cartilage defects with seeded chondrocytes could benefit from the combination with a periosteal graft. The production of TGF-beta by implanted chondrocytes could influence the chondrogenic cells in the periosteum to start a periosteal chondrogenesis and together with the matrix from implanted chondrocyte production, a repair of cartilaginous appearance may develop; a dual chondrogenic response is possible.
OBJECTIVE: Rheumatoid arthritis (RA) is an autoimmune disease, characterized by a chronic inflammation in the joints. The model of collagen-induced arthritis (CIA) has been extensively used to elucidate the pathogenic mechanisms relevant to human RA and is widely employed for the evaluation of potential anti-rheumatic agents. Etoposide and mitoxantrone are immunosuppressive drugs, both acting by inhibiting the topoisomerase II function. We have previously demonstrated an ameliorating effect of etoposide in CIA. The aims of this study were (1) to assess the optimal ameliorating dose of etoposide and (2) to ascertain that topoisomerase II inhibition, irrespective of the chemical composition of the drug, affects the course of autoimmunity. METHODS: Male DBA/1 mice were treated with 12.5 mg/kg body weight of etoposide five times, twice, once per week or once every second week. Mitoxantrone was administered as high dose (1 mg/kg body weight five times after immunization or after booster with collagen II) or low dose (3 microg/mouse, 5 days/week starting after collagen II immunization or after booster). RESULTS: Treatment with 12.5 mg/kg body weight five times or twice weekly with etoposide completely inhibited development of arthritis. Low-dose treatment with mitoxantrone after collagen II immunization or high-dose treatment after collagen II booster delayed the onset of arthritis. These results were observed clinically as well as histologically. In addition, serum levels of anti-collagen II antibodies were significantly lower in mice displaying less severe arthritis. CONCLUSION: Treatment of collagen-induced arthritis with topoisomerase II inhibitors ameliorates the development of disease.
OBJECTIVES: The aim of the study was to assess the role of extracellular cytochrome c as an inducer of joint inflammation and to examine its levels in sera and synovial fluids of rheumatoid arthritis (RA) patients. METHODS: Mice were injected intra-articularly with different doses of cytochrome c and joints were evaluated histopathologically and immunohistochemically 3 and 10 days later. In addition, mouse spleen cells were stimulated with different concentrations of cytochrome c, followed by assessment of NF-kappaB activation and cytokine production. Sera and synovial fluid from RA patients and sera from healthy individuals were assessed with respect to cytochrome c levels by an enzyme-linked immunoassay technique. RESULTS: Histopathological signs of arthritis were evident in 75% of animals following intra-articular injection of cytochrome c. Synovitis was characterized by influx of Mac-1+ cells. In vivo depletion of neutrophils and monocytes led to abrogation of arthritis. Stimulation of mouse spleen cells in vitro with cytochrome c resulted in activation of NF-kappaB and release of proinflammatory cytokines and chemokines. Cytochrome c levels in RA patients' sera were significantly lower than in healthy controls. Further, cytochrome c levels in synovial fluid were significantly lower than in corresponding blood samples. CONCLUSIONS: Our findings demonstrate that extracellular cytochrome c displays direct proinflammatory properties mediated by activation of NF-kappaB and causing neutrophil and monocyte triggered inflammation. We hypothesize that decreased levels of cytochrome c in RA patients reflect consumption of this molecule in the synovial tissue, decreasing apoptosis and shifting the balance towards inflammation.
The authors performed an open, randomized trial in patients with inclusion body myositis comparing 1) 12-month treatment with oral methotrexate 7.5 mg/week alone (MTX group) with 2) 12-month MTX treatment preceded by 7 days of IV anti-T-lymphocyte immunoglobulin treatment (ATG group). Eleven patients were randomized; 10 patients completed 12 months follow-up. Myometry showed that patients in the ATG group (n = 6) increased in mean muscle strength by 1.4% compared with the MTX group (n = 5), whose muscle strength decreased by 11.1% (p = 0.021).
OBJECTIVE AND DESIGN: The aim of this study was to investigate the impact of the isoflavone genistein on in vivo cell-mediated responses. In addition, we wanted to study the influence of genistein on collagen induced arthritis (CIA) in mice. METHODS: Delayed type hypersensitivity reaction (DTH) to oxazolone and the inflammatory response to olive oil were measured in mice treated with genistein. In addition, the impact of genistein treatment on disease progression and outcome of collagen induced arthritis (CIA) was examined. RESULTS: The DTH reaction to oxazolone and the granulocyte-mediated response were significantly suppressed in genistein-treated as compared to control mice. Also, genistein treatment led to decreased levels of oxazolone-specific antibodies. Histologically, mice exposed to genistein and immunized with collagen II displayed somewhat lower degree of inflammation and joint destruction. In addition, serum levels of autoantibodies to collagen II were significantly lower following genistein-treatment in immunized mice. CONCLUSION: We conclude that genistein exerts evident anti-inflammatory properties affecting granulocytes, monocytes, and lymphocytes.
OBJECTIVE AND DESIGN: In systemic inflammatory diseases such as rheumatoid arthritis, cytokines and chemokines are deeply involved in the development of the disease manifestations. Etoposide is a cytostatic drug, known to deplete the monocyte population in mice and rabbits. We have recently shown that suboptimal doses have a disease-ameliorating effect in collagen II induced arthritis in the absence of monocyte depletion. Anti-arthritic properties parallelled with almost total eradication of production of specific collagen II antibodies. The aim of the present study was to investigate ex vivo and in vitro the function of the mononuclear cells and their production of B cell stimulating cytokines following exposure to etoposide, a topoisomerase II inhibitor. MATERIALS AND METHODS: Spleen cells from mice treated during four weeks with etoposide were cultured and the supernatants were analyzed with respect to content of TNF and IL-6. In addition, cells from the murine macrophage cell clone IC-21 were exposed to etoposide and the production of IL-6, using a bioassay, and the production of TNF, MIP-1alpha, RANTES, and IL-1beta, using sandwich ELISAs, was determined. RESULTS: Spleen cells from etoposide-treated mice secreted lower amounts of IL-6 and TNF as compared to the control animals. In addition, in vitro etoposide-exposed macrophages showed reduced capacity to produce TNF, IL-6 and MIP-1alpha. CONCLUSION: Our results indicate that inhibition of topoisomerase II downregulated the function of monocytes. Owing to its immunoregulatory properties, use of etoposide is suggested in treatment of chronic inflammatory diseases.
The high number of gamma/delta-expressing T cells found in the epithelial lining layer suggests that they form a first line of defence against invading pathogens. To evaluate the role of gamma/delta T cell-receptor (TCR)-expressing cells in cutaneous infection caused by Staphylococcus aureus, mice lacking gamma/delta-expressing T cells (TCRdelta-/-) were inoculated intradermally with S. aureus, and compared with S. aureus-infected congeneic TCRdelta+/- control mice. The number of bacteria recovered from the skin of TCRdelta-/- mice was significantly higher (P = 0.0071) at early time-points after inoculation compared to the number of bacteria isolated from infected TCRdelta+/- congeneic controls. Nevertheless, inflammatory responses measured as serum IL-6 levels, were significantly lower in TCRdelta-/- mice than in the control group. A possible explanation for this discrepancy was the observation of significantly decreased overall numbers of infiltrating cutaneous T lymphocytes, which are important producers of IL-6. These results support the notion that the gamma/delta-expressing T cells that reside at the epithelial lining layer of the skin is of importance for early containment of the bacteria, thereby limiting their replication and spread.
BACKGROUND: Leptin has been shown to participate in bone remodelling and leptin substitution reported to have a protective effect in experimental septic arthritis. OBJECTIVE: To assess leptin levels in inflamed joints and plasma of patients with RA. MATERIAL AND METHODS: Leptin concentrations were assessed in matched blood and synovial fluid samples from 76 patients with RA. Blood samples from 34 healthy subjects acted as additional controls. Results were analysed and correlated with duration and activity of RA, x ray changes, and treatment at time of sampling. RESULTS: In patients with RA, leptin levels were significantly higher in plasma than in synovial fluid samples obtained simultaneously and higher than in control samples. Plasma and synovial fluid leptin levels correlated strongly. Locally in the joint, leptin levels were related to WBC count. Such a relation was not seen in the bloodstream. Leptin levels were not related to sex, age, or disease duration. Difference between leptin levels in plasma and synovial fluid was greater in non-erosive arthritis (5.1 (SEM 1.2) v 3.7 (0.9) ng/ml, p=0.006), than in patients with erosive joint disease (6.2 (1.0) v 5.4 (0.8) ng/ml, NS). Methotrexate treatment was associated with relatively high plasma leptin levels, while treatment with other DMARDs was associated with lower leptin levels than in patients receiving no DMARD treatment (p=0.0005). CONCLUSIONS: Leptin production was significantly increased in patients with RA compared with healthy controls. Synovial fluid leptin levels were significantly lower than in matched plasma samples, suggesting an in situ consumption of this molecule.
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OBJECTIVES: To analyse the cerebrospinal fluid (CSF) values of the proinflammatory cytokines, interleukin 1beta (IL1beta), tumour necrosis factor alpha (TNFalpha), GM-CSF, of the anti-inflammatory cytokine TGFbeta, of tau protein, a marker for neurodegeneration, and of beta amyloid (Abeta), a protein involved in the formation of senile plaques, in prospectively followed up patients with mild cognitive impairment (MCI). METHODS: Analyses of CSF levels of TNFalpha, IL1beta, GM-CSF, TGFbeta, betaa, and tau protein were performed using ELISA in 56 patients with MCI who were followed up prospectively and in 25 age matched, healthy controls. RESULTS: Patients with MCI displayed significantly higher levels of TNFalpha and tau protein and significantly lower levels of TGFbeta and Abeta compared with the healthy controls. After nine months of follow up, 25 patients still displayed MCI while the remaining 31 patients had progressed to Alzheimer's disease (AD). Only MCI patients who progressed to AD at follow up, showed significantly higher CSF levels of TNFalpha than controls. In addition, reduced CSF-Abeta42 levels were only found in MCI patients that progressed to AD, further supporting the notion that disturbed metabolism of Abeta is an early finding in AD. CONCLUSIONS: These results demonstrate increased production of the proinflammatory cytokine, TNFalpha and decreased production of the anti-inflammatory cytokine TGFbeta in patients with MCI at risk to develop AD, suggesting a propensity towards inflammation in this patient group and indicating that CNS inflammation is a early hallmark in the pathogenesis of AD.
Few diseases in clinical medicine cause as much diagnostic consternation as central nervous system (CNS) vasculitis because of its varying modes of presentation and frequently overlapping clinical and pathological features. There are no pathognomonic clinical or laboratory findings. The purpose of the present retrospective study was to validate the use of the light subunit of neurofilament triplet protein (NFL) and glial fibrillary acidic protein (GFAP) as markers of CNS tissue damage for patients with systemic or isolated CNS vasculitis. Levels of cerebrospinal fluid (CSF) NFL and GFAP were measured using ELISAs. Both CSF NFL and CSF GFAP concentrations were significantly higher in a patient group diagnosed with CNS vasculitis (P < 0.01 and P < 0.05, respectively) than in a patient group for whom CNS vasculitis was excluded. In the future, analysis of CSF NFL in particular, but also GFAP, may be a useful complement in the difficult clinical task of diagnosing CNS vasculitis.
OBJECTIVE: Fibrin accumulation in the joint cavity is a common feature of chronic arthritides, such as rheumatoid arthritis (RA). Complex formation between tissue factor (TF) and factor VII (FVII) is the initial step in such a fibrin formation. METHODS: To assess the role of the TF/FVII complex in the pathogenesis of joint inflammation, 1) the levels of TF/FVII complex were measured in synovial fluid of RA patients; 2) the complex was injected to healthy mice intra-articularly. RESULTS: Morphological analysis of the joints 4 days after TF/FVII injection revealed influx of CD4-Mac1+ mononuclear leukocytes into synovial tissue followed by cartilage and bone destruction. Inflammation induced by TF/FVII complex was more profound than that caused by each of the proteins separately, both with respect to frequency, severity and duration of arthritis. Interaction between macrophages and lymphocytes in sustaining joint inflammation was proved by the requirement of the combined lymphocyte/ monocyte depletion to abolish TF/FVII induced arthritis. Induction of monocyte attracting chemokines (MIP-1 alpha and RANTES) was shown to be one of the potential mechanisms for TF/FVII complex triggered inflammatory cell influx. Interestingly, TF/FVII complexes were detected in synovial fluid of 20/40 patients with RA. CONCLUSIONS: Altogether these findings indicate that TF/FVII complexes, frequently found intra-articularly in joints of RA patients, may be an important component in both induction and progression of chronic destructive arthritis.
Staphyllococcus aureus-induced infections often result in high mortality and permanent joint destruction, despite treatment with antibiotics. IL-10 is typically regarded as an anti-inflammatory cytokine because it promotes a T helper cell type 2 response, and subsequently down-regulates cell mediated immune functions. To investigate the role of IL-10 in S. aureus-induced arthritis and sepsis, Balb/c mice, intact or defective with respect to IL-10 gene were intravenously inoculated with bacteria. IL-10-/- mice develop a more frequent and destructive arthritis compared to their congeneic controls. The mechanisms regulating such outcome may be due not only to the anti-inflammatory properties of IL-10 but also, directly or indirectly, to antibacterial features of this molecule. Indeed, inoculation of staphylococci to IL-10-/- mice resulted in higher bacterial load in blood and kidneys compared to congeneic controls. Altogether our data indicate that IL-10 is essential for efficient elimination of bacteria and thereby for protection against septic arthritis.