Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018099 (gout)
 5,192 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A number of cells, chemotactic factors, and inflammatory mediators are implicated in the complex mechanisms underlying crystal-mediated inflammation. Interleukin-8, released from mononuclear cells that have been exposed to urate and other crystals, is a potent chemotaxin and activator of neutrophils. Experimental and clinical observations suggest that joint movements, local biomechanical factors, and previous joint damage may play a role in influencing the intensity of microcrystalline synovitis and the distribution of articular and periarticular crystal deposits in both calcium pyrophosphate dihydrate crystal deposition disease and gout. There are rare reports of extra-articular calcium pyrophosphate dihydrate crystal deposition in tendons, bursae, dura mater, and ligamentum flavum (with radiculomyelopathy) and of massive "tumoral," tophuslike, periarticular calcium pyrophosphate dihydrate crystal deposits. Synovial fluid levels of ATP, the main substrate for nucleoside triphosphate pyrophosphohydrolase ectoenzyme, which cleaves ATP-releasing inorganic pyrophosphate, are higher in patients with calcium pyrophosphate dihydrate crystal deposition disease than in those with other arthritides, and the levels correlate with inorganic pyrophosphate concentrations. Further reports of acute calcific periarthritis of the first metatarsophalangeal joint (hydroxyapatite pseudopodagra) in young women have been described. The mitogenic response of fibroblasts to stimulation with basic calcium phosphate crystals is accompanied by induction and secretion of collagenase and neutral proteases, implicating a role for the crystals in the pathogenesis of both synovial proliferation and joint damage in chronic basic calcium phosphate crystal-associated arthropathy. Subcutaneous cholesterol crystal deposition with tophus formation is extremely rare and has been described in a patient with scleroderma and calcinosis cutis.
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PMID:Calcium pyrophosphate crystal deposition disease and other crystal deposition diseases. 150 84

Human neutrophils at inflammatory sites may be an important source of the chemotactic cytokines macrophage inflammatory protein 1 alpha (M1P-1 alpha; a C-C chemokine) and interleukin 8 (IL-8; a C-X-C chemokine). In this study, we show that the inflammatory microcrystals monosodium urate monohydrate (MSU) and calcium pyrophosphate dihydrate (CPPD), the major mediators of gout and pseudogout, differentially regulate the production of these two chemokines by human neutrophils. Both MSU and CPPD increased the secretion of IL-8 by neutrophils in a dose- and time-dependent manner, but had no effect on that of MIP-1 alpha. Since inflammatory cytokines are likely to be present in the synovium during crystal-induced inflammation, we examined the interaction between TNF-alpha and GM-CSF and the crystals. Both TNF-alpha and GM-CSF stimulated IL-8 production; however, only TNF-alpha exerted a significant effect on MIP-1 alpha secretion in neutrophils. IL-8 production induced by TNF-alpha and GM-CSF was synergistically enhanced in the presence of MSU or CPPD, whereas MIP-1 alpha secretion induced by TNF was completely inhibited in the presence of either MSU or CPPD. Interestingly, no interaction between the crystals and the inflammatory cytokines was observed with respect to synthesis of the C-X-C chemokine MGSA in neutrophils. These results suggest that the combination of TNF-alpha and GM-CSF with MSU or CPPD will lead to the production of IL-8 by neutrophils and abolish the release of MIP-1 alpha, an event that will theoretically lead to recruitment of neutrophils but not mononuclear cells. These results are in accordance with the pathological state of gout and pseudogout, where the predominant inflammatory cell is the neutrophil.
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PMID:Inflammatory microcrystals differentially regulate the secretion of macrophage inflammatory protein 1 and interleukin 8 by human neutrophils: a possible mechanism of neutrophil recruitment to sites of inflammation in synovitis. 750 47

IL-8 was measured in knee joint synovial fluid of 60 patients with rheumatoid arthritis, 8 with gout, 6 with osteoarthritis and 4 with meniscus lesions. IL-8 could be demonstrated in most SF samples. The highest levels were observed in rheumatoid joint effusions, yet mean levels were not significantly different between the different subgroups (mean +/- SE; RA 1537 +/- 3049 pg/ml, gout 570 +/- 952 pg/ml, OA/ML 178 +/- 188 pg/ml). In RA patients, IL-8 levels could not be related to various serological, clinical or radiological parameters. However, a correlation was observed between SF levels of IL-8 with those of lactate, LDH, beta 2-microglobulin and glucose. These observations suggest that next to the laboratory parameters IL-8 will be a parameter of the activity of the local inflammatory process. The results also demonstrate that IL-8 is not a disease-specific marker of joint inflammation.
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PMID:Interleukin-8 (IL-8) in synovial fluid of rheumatoid and nonrheumatoid joint effusions. 812 12

Macrophages infiltrated into synovium play an important role in joint destruction in inflammatory joint diseases. In this study we focused on the production of monocyte chemoattractant protein-1 (MCP-1), a recently identified monocyte chemotactic protein, by inflammatory synovium. Synovial fluid (SF) from rheumatoid arthritis (RA), osteoarthritis, gout, and traumatic arthritis contained MCP-1. MCP-1 was produced in the synovium of patients with RA and other inflammatory joint disease in in vitro culture systems; differences in the amounts produced were not significant. Synovial MCP-1 production in RA was further investigated. Levels of MCP-1 were significantly correlated with levels of IL-1 beta, IL-6, and IL-8 in the culture supernatants of synovia from RA. Using immunohistochemical techniques, MCP-1 was detected in the lining and sublining cells and in the vascular endothelial cells of rheumatoid synovia. Rheumatoid synovia with active inflammation were stained more intensely by anti-MCP-1 antibody than were those with weak or inactive inflammation. IL-1 beta and TNF-alpha stimulated the expression of MCP-1 mRNA and de novo MCP-1 synthesis by cultured synovial cells. These results suggest the production of MCP-1 by synovium of various inflammatory joint diseases. In rheumatoid synovium, a cytokine network involving MCP-1 and other proinflammatory cytokines (IL-1 beta, IL-6, IL-8, and TNF-alpha) contributes to the immunopathogenesis of RA.
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PMID:Monocyte chemoattractant protein-1 (MCP-1) in inflammatory joint diseases and its involvement in the cytokine network of rheumatoid synovium. 840 45

Activin A is a cytokine whose multiple functions have yet to be fully determined. In this study, the role of proinflammatory cytokines in regulatory control of activin A production was shown in synoviocytes and chondrocytes. Additional facets of functional inflammation-related activities of activin A were also determined. Results showed that activin A concentrations in the synovial fluid of patients with rheumatoid arthritis and gout were elevated relative to those in patients with osteoarthritis. Further studies showed that production of activin A by synoviocytes and chondrocytes in culture was stimulated by cytokines such as IL-1, transforming growth factor-beta (TGF-beta), interferon-gamma (IFN-gamma), and IL-8, consistent with previous studies in regard to the control of activin A production in marrow stromal cells and monocytes by cytokines, glucocorticoids and retinoic acid. In addition, the relationship of activin A to IL-6-induced biological activities was investigated. Three major IL-6 activities involved in inflammatory responses were found to be suppressed by activin A. In a dose-dependent manner, activin A efficiently suppressed IL-6-induced proliferation of 7TD1 B lymphoid cells, phagocytic activity of monocytic M1 cells, and fibrinogen production in HepG2. Therefore, it is likely that activin A serves as a suppressor for IL-6, dampening inflammatory responses, and has the potential to perform some previously unrecognized roles in inflammation.
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PMID:Suppression of IL-6 biological activities by activin A and implications for inflammatory arthropathies. 956

In the present study, we analyzed the cytokine network among TNFalpha, IL-1beta, IL-8, and IL-1 receptor antagonist (IL-1Ra) in a rabbit experimental model of acute gout. The production of TNFalpha in synovial fluids reached the peak at 2 hours after the intra-articular injection of monosodium urate (MSU) crystals. The production of IL-1beta and IL-8 reached the first peak at 2 hours and the second peak at 9 and 12 hours, respectively. The production of endogenous IL-1Ra reached the peak at 9 hours. The source of TNFalpha and the first phase of IL-8 was synovial cells, whereas infiltrating leukocytes were the source of the second phase of IL-8 and also of IL-1beta and IL-1Ra. The production of TNFalpha was not altered by either anti-lL-8 IgG or IL-1Ra. The first IL-1beta peak was reduced only with a combination of anti-TNFalpha mAb and anti-lL-8 IgG, whereas the second peak was significantly reduced by either inhibitor. The first IL-8 peak was not altered with anti-TNFalpha mAb or IL-1 Ra, whereas the second IL-8 peak was reduced with IL-1Ra. Anti-TNFalpha mAb or anti-lL-8 IgG significantly reduced the peak level of endogenous IL-1Ra. These cytokine inhibitors also attenuated the maximal leukocyte accumulation at 9 hours, but not the initial phase, which occurred within 2 hours. These results provide evidence that IL-8 and TNFalpha were responsible for the production of IL-1beta and IL-1Ra, and that IL-1beta was responsible for the second phase of IL-1beta and IL-8 production. Our data also suggest that the initial and the maximal phases of leukocyte influx are differently regulated. Finally, the intravenous injection of colchicine inhibited neutrophil infiltration without affecting the production of TNFalpha or the first peak of IL-8, suggesting that colchicine inhibits MSU crystal-induced arthritis by directly inhibiting the migration of neutrophils.
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PMID:Analysis of the cytokine network among tumor necrosis factor alpha, interleukin-1beta, interleukin-8, and interleukin-1 receptor antagonist in monosodium urate crystal-induced rabbit arthritis. 960 81

Synovial fluids (SF) from patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), gout, and osteoarthritis (OA) were investigated for the levels of interleukin (IL)-1 beta, IL-6 and IL-8, tryptophan (Trp) and indoleamine 2,3-dioxygenase (IDO) activity. Significant differences exist in the levels of IL-1 beta between inflammatory arthritides RA, PsA and gout and non inflammatory arthritis, such as OA. The highest concentration of IL-1 beta was found in RA, that showed high levels also of IL-6 and IL-8. In the same disease we also found the highest IDO activity and the lowest Trp concentration. In addition, IDO activity seems to be related with the decrease in Trp, as demonstrated by the inverse correlation found between these two substances in the SF of all patients.
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PMID:Tryptophan catabolism in synovial fluid of various arthropathies and its relationship with inflammatory cytokines. 1072 Nov 1

Neutrophil-dependent inflammation dependent on monosodium urate (MSU) crystal-induced IL-8 expression occurs in gout. MSU crystals activate phagocyte Src family tyrosine kinases and the serine/threonine kinase p70s6k. Thus, using monocytic THP-1 cells, we assessed the potential for Src family kinases and p70s6k to mediate MSU-induced IL-8 expression. MSU crystals induced phosphorylation of p70s6k and the Src kinases c-Src, Lyn, Hck, and Fyn. IL-8 expression was attenuated more by the Src kinase inhibitor PP1 than by the p70s6k inhibitor rapamycin. PP1 inhibited crystal-induced phosphorylation of ERK1/2 and IkappaBalpha and suppressed IkappaB kinase (IKK) activation and NF-kappaB binding to the IL-8 promoter, signals that mediate MSU-induced IL-8 expression. Transfection of the native Src inhibitor, C-terminal Src kinase (Csk), also suppressed crystal-induced c-Src, ERK1/2, and IkappaBalpha phosphorylation and IL-8 expression. We conclude that Src family tyrosine kinase signaling plays a significant role in MSU crystal-induced IL-8 expression via stimulation of ERK1/2 pathway and NF-kappaB activation.
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PMID:Src family protein tyrosine kinase signaling mediates monosodium urate crystal-induced IL-8 expression by monocytic THP-1 cells. 1173 59

Cytokines are a complex family of small regulatory proteins able to mediate intercellular communication and play a crucial role in immunologic and inflammatory reactions. Many reports have demonstrated that some cytokines, in particular tumor necrosis factor alpha (TNFalpha) and interleukin (IL)-1beta, IL-6, and IL-8, so-called proinflammatory, may have a major role in the pathogenesis of joint diseases. Thus, high levels of these substances have been found in inflammatory arthropathies, in particular in those characterized by a more aggressive and destructive outcome, such as rheumatoid arthritis, gout, and infectious arthritis. In keeping with their role, the determination of cytokines in synovial fluid may be proposed for clinical purposes, including diagnostic and prognostic assessments. Furthermore, as some of these cytokines may reflect disease activity, their determination may also be useful in the evaluation of therapy.
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PMID:Clinical significance of cytokine determination in synovial fluid. 1189 Feb 8

Chronic crystal-associated arthropathies such as gout and pseudogout can lead to local bone destruction. Because osteoblasts, which orchestrate bone remodeling via soluble factors and cell-to-cell interactions, have been described in contact with microcrystals, particularly in uratic foci of gout, we hypothesized that microcrystals of monosodium urate monohydrate (MSUM) and of calcium pyrophosphate dihydrate (CPPD) could alter osteoblastic functions. MSUM and CPPD adhered to human osteoblastic cells (hOB) in vitro and were partly phagocytized as shown by scanning electron microscopy. MSUM and CPPD dose-dependently stimulated the production of PGE(2) in hOB as assessed by enzyme immunoassay, a response that was synergistically enhanced in the presence of IL-1. The mechanism of this synergism was, at least in part, at the level of the expression of cyclooxygenase-2 as evaluated by immunoblot analysis. MSUM and CPPD also stimulated the expression of IL-6 and IL-8 and reduced the 1,25-dihydroxyvitamin D(3)-induced activity of alkaline phosphatase and osteocalcin in hOB (with no synergism with IL-1). MSUM- or CPPD-stimulated expression of IL-6 in hOB pretreated with the selective cyclooxygenase-2 inhibitor NS-398 was increased, unlike that induced by IL-1 alone which was partially reduced. MSUM-, CPPD- or IL-1-induced expression of IL-8 was unchanged by pretreating hOB with NS-398. These results suggest that inflammatory microcrystals alter the normal phenotype of hOB, redirecting them toward reduced bone formation and amplified osteoblast-mediated bone resorption, abnormalities that could play a role in the bone destruction associated with chronic crystal-induced arthritis.
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PMID:Inflammatory microcrystals alter the functional phenotype of human osteoblast-like cells in vitro: synergism with IL-1 to overexpress cyclooxygenase-2. 1199 89


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