leukotriene-b4 and Arthritis--Rheumatoid

Leukotriene B

Topics: Animals; Arthritis, Rheumatoid; Leukotriene B4; Mice; Receptors, Leukotriene B4; Skin

Rheumatoid arthritis (RA) is a chronic, autoimmune inflammatory disease of multiple joints that puts the patient at high risk for developing cardiovascular diseases (CVDs). The aim of the present study was to conduct an up-to-date systematic review and meta-analysis of published randomized controlled trials (RCTs) to assess potential changes in RA disease activity, inflammation, and CVD risk after oral intake of ω-3 polyunsaturated fatty acids.. Publications up to July 31, 2016 were examined using the PubMed, SCOPUS, and EMBASE databases.. English language; human subjects; both sexes; RCTs; oral intake of ω-3 fatty acids; minimum duration of 3 mo; and no medication change throughout intervention. The Cochrane Risk of Bias tool was used to assess quality of trials. We included 20 RCTs, involving 717 patients with RA in the intervention group and 535 RA patients in the control group.. The beneficial properties of ω-3 polyunsaturated fatty acids on RA disease activity confirm the results of previous meta-analyses. Among five proinflammatory markers evaluated, only leukotriene B4 was found to be reduced. However, a positive effect on blood lipid profile of patients with RA was evident, perhaps for the first time.

Topics: Arthritis, Rheumatoid; Biomarkers; Cardiovascular Diseases; Fatty Acids, Omega-3; Humans; Leukotriene B4; Randomized Controlled Trials as Topic; Triglycerides

Inflammatory arthritis, including rheumatoid arthritis (RA), is characterized by infiltration of inflammatory cells into the joints. Biological agents targeting TNF-α and IL-6 dramatically improve RA. However, some RA patients do not respond to current treatments and these broadly active upstream biological agents increase the risk of severe infection. Therefore, there remains a need for other effective and safe treatments for RA. Many studies have implicated that blockade of leukotriene B4 (LTB

Topics: Animals; Arthritis; Arthritis, Rheumatoid; Clinical Trials as Topic; Disease Models, Animal; Humans; Inflammation; Leukotriene B4; Molecular Targeted Therapy; Receptors, Leukotriene B4

Marine-derived n-3 polyunsaturated fatty acids (PUFA) may have a beneficial effect on inflammation via lowering pro-inflammatory eicosanoid concentrations. We aimed to assess the effect of marine-derived n-3 PUFA on prostaglandin E2 (PGE2), thromboxane B2 (TXB2), and leukotriene B4 (LTB4) through systematic review and meta-analysis of randomized controlled trials.. A structured search strategy on PubMed, Web of Science and Cochrane up to November 2015 was undertaken in this meta-analysis. Standard mean difference was used to calculate the effect size of marine-derived n-3 PUFA on PGE2, TXB2 and LTB4 in a random-effect model. A total of 18 RCTs with 826 subjects were included in this systematic review and meta-analysis. Supplementation of marine-derived n-3 PUFA significantly decreased concentrations of TXB2 in serum/plasma in subjects with high risk of cardiovascular diseases (SMD:-1.26; 95% CI: -1.65, -0.86) and LTB4 in neutrophils in unhealthy subjects (subjects with non-autoimmune chronic diseases or auto-immune diseases) (SMD:-0.59: 95% CI: -1.02, -0.16). Subgroup analyses showed a significant reduction of LTB4 in subjects with rheumatoid arthritis (SMD: -0.83; 95% CI: -1.37, -0.29), but not in non-autoimmune chronic disease patients (SMD: -0.33; 95% CI: -0.97, 0.31). No significant publication bias was shown in the meta-analysis.. Marine-derived n-3 PUFA had a beneficial effect on reducing the concentration of TXB2 in blood of subjects with high risk of CVD as well as LTB4 in neutrophils in unhealthy subjects, and that subjects with RA showed lower LTB4 content with supplementation of marine-derived n-3 PUFA.

Topics: Anti-Inflammatory Agents; Arthritis, Rheumatoid; Chronic Disease; Dietary Supplements; Dinoprostone; Dose-Response Relationship, Drug; Eicosanoids; Fatty Acids, Omega-3; Fish Oils; Humans; Leukotriene B4; Randomized Controlled Trials as Topic; Research Design; Thromboxane B2; Treatment Outcome

The purpose of this review is to summarize the role that murine models of arthritis are playing in the understanding of human rheumatoid arthritis and how leukotriene B(4) (LTB(4)) is emerging as an important target in this field. Both the collagen-induced arthritis (CIA) model and the K/BxN serum transfer arthritis model have contributed to outline the potential mechanisms involved in inflammatory arthritis. Indeed, the CIA model has contributed to the development of effective anti-TNFalpha and anti-IL-1beta based treatments for RA that are currently in the clinic. Many recent studies in mouse models have suggested a critical role for LTB(4) and its receptors in the development of inflammatory arthritis. Inhibitors of LTB(4) biosynthesis as well as LTB(4) receptors are protective in mouse models of RA and mice deficient in the LTB(4) biosynthetic enzymes or LTB(4) receptors are resistant to disease development suggesting several promising targets for RA in this pathway.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Cytokines; Disease Models, Animal; Leukotriene B4; Receptors, Leukotriene B4

Topics: Abatacept; Animals; Arthritis, Rheumatoid; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cells, Cultured; Chemotaxis, Leukocyte; Humans; Immunoconjugates; Immunologic Memory; Leukotriene B4; Mast Cells; Mice; Models, Immunological; Receptors, Leukotriene B4; Receptors, Purinergic P2; Synovial Membrane; T-Lymphocyte Subsets

Many antiinflammatory pharmaceutical products inhibit the production of certain eicosanoids and cytokines and it is here that possibilities exist for therapies that incorporate n-3 and n-9 dietary fatty acids. The proinflammatory eicosanoids prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)) are derived from the n-6 fatty acid arachidonic acid (AA), which is maintained at high cellular concentrations by the high n-6 and low n-3 polyunsaturated fatty acid content of the modern Western diet. Flaxseed oil contains the 18-carbon n-3 fatty acid alpha-linolenic acid, which can be converted after ingestion to the 20-carbon n-3 fatty acid eicosapentaenoic acid (EPA). Fish oils contain both 20- and 22-carbon n-3 fatty acids, EPA and docosahexaenoic acid. EPA can act as a competitive inhibitor of AA conversion to PGE(2) and LTB(4), and decreased synthesis of one or both of these eicosanoids has been observed after inclusion of flaxseed oil or fish oil in the diet. Analogous to the effect of n-3 fatty acids, inclusion of the 20-carbon n-9 fatty acid eicosatrienoic acid in the diet also results in decreased synthesis of LTB(4). Regarding the proinflammatory ctyokines, tumor necrosis factor alpha and interleukin 1beta, studies of healthy volunteers and rheumatoid arthritis patients have shown < or = 90% inhibition of cytokine production after dietary supplementation with fish oil. Use of flaxseed oil in domestic food preparation also reduced production of these cytokines. Novel antiinflammatory therapies can be developed that take advantage of positive interactions between the dietary fats and existing or newly developed pharmaceutical products.

Topics: alpha-Linolenic Acid; Arachidonic Acid; Arthritis, Rheumatoid; Dietary Fats; Dinoprostone; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; Female; Fish Oils; Humans; Inflammation; Inflammation Mediators; Interleukin-1; Leukotriene B4; Linseed Oil; Male; Tumor Necrosis Factor-alpha

A number of studies show the efficacy of methotrexate (MTX) for rheumatoid arthritis (RA) in general. However, is there any reason to single this drug out for early RA? Mechanistically, it probably works differently in RA than in cancer, at least in part. Thus, in addition to dihydrofolate reductase-related effects, MTX inhibits aminoimidazocarboxamide transformylase, decreases leukotriene B4 production, and increases adenosine release at concentrations achieved with low-dose MTX regimens. Clinically, it is well tolerated over relatively long periods. Further, a recent meta-analysis of radiology studies shows that MTX compares favorably with intramuscular gold and is better than azathioprine. Toxicity remains a concern in treating early RA, particularly as pulmonary "hypersensitivity reactions" continue (1% to 7.6%), infections (both fungal and perioperative) are documented, and more cirrhosis is found. With all of the above in mind, the use of MTX seems reasonable but not necessarily uniformly appropriate and not yet proved for early RA. Studies of MTX in early RA, particularly in combination with other drugs, are only beginning.

Topics: Adenosine; Arthritis, Rheumatoid; Clinical Trials as Topic; Humans; Leukotriene B4; Lymphocytes; Meta-Analysis as Topic; Methotrexate; Neutrophils

Topics: Animals; Arthritis, Rheumatoid; Humans; Interleukin-1; Leukotriene B4; Prostaglandins

The arachidonic acid substitution by an alternative fatty acid, substrate for the 5-lipoxygenase and the cyclo-oxygenase pathway constitutes a novel therapeutic approach or a complement for other therapeutics in the inflammation area. Eicosapentaenoic acid (EPA), one of the fish oil components, is a substrate for both enzymes and an inhibitor for several enzymes of arachidonic acid cascade, in vitro and in vivo. The EPA-generated metabolites have less pro-inflammatory effects than those produced by arachidonic acid metabolism.

Topics: Arachidonate 5-Lipoxygenase; Arthritis, Rheumatoid; Eicosapentaenoic Acid; Fish Oils; Humans; Inflammation; Leukotriene B4; Neutrophils

The leukotrienes (LTs) are a novel group of biologically active mediators derived from arachidonic acid via lipoxygenase enzymes. LTB4 is a potent chemotactic agent for polymorphonuclear leukocytes and in vivo may mediate inflammatory reactions by inducing leukocyte recruitment by mediating indirectly vascular permeability charges and by modulating pain responses. LTC4 and LTD4 collectively account for the biological activity known as slow-reacting substance of anaphylaxis and are potent smooth muscle contracting agents. They may mediate inflammatory reactions by producing changes in blood flow and increases in vascular permeability. Evidence for LT involvement in a number of pathological conditions including diseases such as asthma, psoriasis, ulcerative colitis, and gout is now accumulating.

Topics: Animals; Arthritis, Rheumatoid; Asthma; Colitis, Ulcerative; Gout; Humans; In Vitro Techniques; Inflammation; Leukotriene B4; Neutrophils; Psoriasis; Rabbits; SRS-A

Topics: Animals; Arachidonic Acids; Arthritis, Rheumatoid; Edema; Eosinophils; Guinea Pigs; Humans; Hypersensitivity; Leukotriene B4; Mast Cells; Mice; Muscle Contraction; Nephritis; Prostaglandin D2; Prostaglandins; Prostaglandins D; Rabbits; Rats; Receptors, Fc; Receptors, IgE; Receptors, Immunologic; SRS-A; Thromboxanes

To observe the effects of moxibustion on the contents of leukotriene B4 (LTB4), interleukin-17 (IL-17), tumor necrosis factor-α (TNF-α) and matrix metalloproteinase -9 (MMP-9) in serum, and explore the protection mechanisms of moxibustion in the patients with rheumatoid arthritis (RA).. A total of 64 patients with RA were randomly divided into treatment group (. After treatment, VAS score, morning stiffness score, the number of tender joints, the number of swollen joints, DAS28 score, the contents of serum RF in both groups, and contents of serum CRP, ESR, LTB4, IL-17, TNF-α and MMP-9 in the treatment group were significantly reduced when compared with those before treatment (. Moxibustion at BL23 and ST36 combined with conventional medication significantly relieves joint pain and reduce disease activity in RA patients, which may be related to the modulation of LTB4, IL-17 and MMP-9 by moxibustion.

Topics: Arthritis, Rheumatoid; Humans; Interleukin-17; Leukotriene B4; Matrix Metalloproteinase 9; Moxibustion; Tumor Necrosis Factor-alpha

Leukotriene B4 (LTB(4)) has a key role in the pathophysiology of rheumatoid arthritis (RA).. To investigate the inhibition of ex vivo LTB(4)-induced Mac-1 (CD11b/CD18) expression in leucocytes of patients with RA by the new oral LTB(4) receptor antagonist BIIL 284.. The pharmacokinetics and inhibition of LTB(4)-induced Mac-1 expression of BIIL 284 were characterised in 26 adult patients with RA who were treated with BIIL 284 25 mg, 150 mg, or placebo given once a day for 14 days according to a double blind, randomised, parallel group design.. T(max) of BIIL 315 in plasma (main metabolite and active principle of BIIL 284 in plasma) was achieved about four hours after drug administration, and C(max,ss) and AUC(0-6h,ss) increased in proportion to the dosage. 100% inhibition of LTB(4)-induced MAC-1 expression was reached after two hours (150 mg) or four hours (25 mg), showing a statistically significant difference in comparison with placebo (p<0.005). A longlasting dynamic effect was seen consistently even when plasma concentrations declined to very low values 24 hours after administration. Secondary clinical efficacy end points remained unchanged probably owing to the short duration of treatment. Adverse events (AEs) were reported in 12 patients during the study. No serious AEs or laboratory AEs were seen.. Both the 25 mg and 150 mg doses of BIIL 284 safely and effectively inhibit Mac-1 expression on neutrophils; thus longer treatment with BIIL 284 may result in clinical benefit for patients with RA.

Topics: Adolescent; Adult; Aged; Amidines; Area Under Curve; Arthritis, Rheumatoid; Carbamates; Double-Blind Method; Female; Humans; Leukotriene Antagonists; Leukotriene B4; Macrophage-1 Antigen; Male; Middle Aged; Neutrophils; Time Factors

Dietary gammalinolenic acid (GLA), a potent inhibitor of 5-lipoxygenase (5-LOX) and suppressor of leukotriene B4 (LTB4), can attenuate the clinical course of rheumatoid arthritics, with negligible side effects. Since Zileuton, also an inhibitor of 5-LOX, attenuates asthma but with an undesirable side effect, we investigated whether dietary GLA would suppress biosynthesis of PMN-LTB4 isolated from asthma patients and attenuate asthma. Twenty-four mild-moderate asthma patients (16-75 years) were randomized to receive either 2.0 g daily GLA (borage oil) or corn oil (placebo) for 12 months. Blood drawn at 3 months intervals was used to prepare sera for fatty acid analysis, PMNs for determining phospholipid fatty acids and for LTB4 generation. Patients were monitored by daily asthma scores, pulmonary function, and exhaled NO. Ingestion of daily GLA (i) increased DGLA (GLA metabolite) in PMN-phospholipids; (ii) increased generation of PMN-15-HETrE (5-LOX metabolite of DGLA). Increased PMN-DGLA/15-HETrE paralleled the decreased PMN generation of proinflammatory LTB4. However, the suppression of PMN-LTB4 did not reveal statistically significant suppression of the asthma scores evaluated. Nonetheless, the study demonstrated dietary fatty acid modulation of endogenous inflammatory mediators without side effects and thus warrant further explorations into the roles of GLA at higher doses, leukotrienes and asthma.

Topics: Adult; Aged; Arthritis, Rheumatoid; Asthma; Dietary Supplements; Double-Blind Method; Fatty Acids; Female; gamma-Linolenic Acid; Humans; Hydroxyurea; Leukotriene B4; Lipoxygenase Inhibitors; Male; Middle Aged; Neutrophils; Plant Oils; Prospective Studies

To investigate the potential anti-inflammatory effects of sesame oil, which is present in the injectable gold preparation Auromyose, the synthesis of tumour necrosis factor alpha (TNF-alpha), prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) by in vitro stimulated blood cells was measured before, during and after 12 weeks of dietary supplementation with 18 g of sesame oil daily in 11 healthy male volunteers. Neither TNF-alpha, PGE2 nor LTB4 production levels showed statistically significant changes during the 12 weeks of dietary supplementation with sesame oil. These results do not suggest an anti-inflammatory effect of sesame oil as present in injectable gold preparations which are used in the treatment of rheumatoid arthritis.

Topics: Adolescent; Adult; Antirheumatic Agents; Arthritis, Rheumatoid; Cells, Cultured; Dinoprostone; Drug Combinations; Gold; Humans; Injections, Intramuscular; Leukocytes; Leukotriene B4; Male; Middle Aged; Pilot Projects; Sesame Oil; Tumor Necrosis Factor-alpha

The effects of zileuton, a new 5-lipoxygenase inhibitor, on leukotriene generation and clinical response in rheumatoid arthritis (RA) was studied in a 4-week randomized double blind placebo controlled study at 2 academic rheumatology centers. Zileuton decreased the mean (+/- SEM) ionophore induced synthesis of leukotriene B4 at Week 1 by 70% from 191.2 +/- 28.5 to 57.5 +/- 17.0 ng/ml. A parallel suppression of all major 5-lipoxygenase pathway products was observed. An improvement in clinical variables was observed in the zileuton and placebo treated population. No unique toxicity was identified in this study. Zileuton inhibited 5-lipoxygenase in RA with a suggestion of clinical response with limited toxicity.

Topics: Adult; Aged; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Double-Blind Method; Female; Humans; Hydroxyurea; Leukotriene B4; Lipoxygenase Inhibitors; Male; Middle Aged; Time Factors

The studies reported here were designed to examine the chemotactic potential, arachidonic acid (AA) metabolism and phospholipid transmethylation in peripheral blood neutrophils from patients with rheumatoid arthritis (RA): a) prior to treatment with BW 91Y (3-deazaadenosine), b) after 4 weeks when half the patients were on active medication and half were on placebo, and c) after 4 weeks at which time all patients were on active medication. The authors demonstrate that BW 91Y in vitro at 600 pg/ml caused a decrease in chemotactic potential as measured by the leading front (LF) assay in neutrophils from both normal volunteers (p less than 0.025) and RA patients. They also demonstrate that BW 91Y caused a significant increase in production of [3H]LTB4 (LTB = leukotriene B) in ionophore-stimulated neutrophils from both normal (p less than 0.025) and RA patients (p less than 0.050) as compared to initial values. BW 91Y caused decreased incorporation and percent distribution of [3H]AA into phosphatidylcholine (PC), with a resultant increase in percent distribution into phosphatidylethanolamine (PE). There was also an increased release of [3H]AA from the PE fraction in BW 91Y-treated cells in response to ionophore stimulation. BW 91Y was found to exhibit a dose-dependent (10(-7) to 10(-4) g/ml) inhibition of the uptake and incorporation of L-[methyl-3H]methionine into the cellular lipids, while at low doses (10(-9) to 10(-5) g/ml) it stimulated the significant uptake and incorporation of [methyl-14C]choline chloride into PC. Although the total cellular content and percent composition of PC remained unchanged, it was found that BW 91Y caused a slight decrease in PC plasmalogens and an apparent increase in the 1,2-diacyl-glycerophosphatidylcholine (-GPC). BW 91Y was found, however, to have no effect on the amount or stimulated metabolism of the ether-linked 1-O-alkyl-2-acyl-GPC. As further evidence for this, the authors demonstrate that BW 91Y has no effect on the ionophore-stimulated production of [14C]acetate-labelled 1-O-alkyl-2-acetyl-GPC, or [14C]PAF.

Topics: Arachidonic Acids; Arthritis, Rheumatoid; Calcimycin; Chemotaxis, Leukocyte; Chromatography, Thin Layer; Dose-Response Relationship, Drug; Double-Blind Method; Humans; Leukotriene B4; Lipid Metabolism; Lipids; Neutrophils; Phosphatidylcholines; Phosphatidylethanolamines; Phospholipids; Platelet Activating Factor; Tubercidin

Altogether 53 patients (31 women, 22 men) with definite rheumatoid arthritis were randomly divided into groups of 5-6 patients and treated for one day only with one of the following non-steroidal anti-inflammatory drugs (NSAIDs): acetylsalicylic acid, carprofen, diclofenac, indomethacin, naproxen, proquazone, timegadine, tolfenamic acid or paracetamol, and with prednisolone, in recommended doses. Synovial fluid samples were collected before and after the treatment. White cell count and its differentiation as well as the concentrations of protein, cyclic adenosine-3',5'-monophosphate (cAMP), prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) were measured from the synovial fluid. Synovial fluid leukocyte counts correlated with PGE2 concentrations, but showed no correlation with LTB4 levels before treatment. Significant changes were seen in the form of lowered PGE2 values following treatment with the clinically and experimentally most potent NSAIDs, and as depressed LTB4 levels following prednisolone treatment. The other markers of inflammation are obviously more resistant, changing only slowly during prolonged treatment, and may thus be, at least in part, secondary to the changes in prostanoids.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Cyclic AMP; Dinoprostone; Female; Humans; Leukocyte Count; Leukotriene B4; Male; Osmolar Concentration; Prednisolone; Synovial Fluid

We administered borage seed oil (9 capsules/day) for 12 weeks to 7 normal controls and to 7 patients with active rheumatoid arthritis. The therapy provided 1.1 gm/day of gamma-linolenic acid (GLA). GLA administration resulted in increased proportions of its first metabolite, dihomo-gamma-linolenic acid (DGLA), in circulating mononuclear cells. The ratios of DGLA to arachidonic acid and DGLA to stearic acid increased significantly in these cells. Significant reductions in prostaglandin E2, leukotriene B4, and leukotriene C4 produced by stimulated monocytes were seen after 12 weeks of GLA supplementation. The antiinflammatory effects of GLA administration observed in animal models, and the apparent clinical improvement experienced by 6 or 7 rheumatoid arthritis patients given borage seed oil in this open, uncontrolled study may be due in part to reduced generation of arachidonic acid oxygenation products.

Topics: Administration, Oral; Adult; Arthritis, Rheumatoid; Blood Cells; Dinoprostone; Eicosanoids; Fatty Acids; Female; Humans; Leukotriene B4; Linolenic Acids; Lipids; Male; Middle Aged; Monocytes; SRS-A

Arachidonic acid (AA) metabolism and phospholipase A2 (PLA2) activity were measured in the peripheral blood polymorphonuclear leukocytes (PMNL) from ten patients with rheumatoid arthritis (RA) on treatment with various non-steroidal anti-inflammatory agents (NSAIA). AA metabolism and PLA2 activity were measured both initially and after treatment with either placebo or Clotrimazole, a broad spectrum anti-mycotic agent, as a possible anti-rheumatic drug. AA metabolism was also measured in PMNL from ten patients with active RA untreated with any NSAIA and ten normal volunteers. Using 3H-AA prelabeled cells, we show that there was a significantly higher (P less than 0.025) production of 3H-LTB4 in response to stimulation with the calcium ionophore A23187 in untreated RA patients than in normal volunteers (mean +/- S.D.:4.8 +/- 1.6% and 3.1 +/- 1.0%, respectively). The production of 3H-LTB4 by PMNL from patients on NSAIAs was less elevated (mean +/- S.D.:4.1 +/- 1.5%) and was not significantly different from normal controls. Concurrently we examined PLA2 activity in PMNL-sonicates from ten of our study patients using autoclaved [14C]oleate-labeled E. coli biomembranes as an exogenous substrate. Using linear regression analysis, we demonstrate a significant correlation between in vitro PLA2 activity and the release of 3H-AA from the cellular phospholipids (deacylation) in response to A23187 stimulation (r = -0.526, P less than 0.025). We also demonstrate significant correlations between the overall clinical state of the RA patient, as evaluated by a modified rheumatoid activity index (MRAI), and both the release of 3H-AA from the cellular phospholipids and its production of total [3H]eicosanoids (r = -0.557, P less than 0.025 and r = 0.644, P less than 0.005, respectively). This data suggests that: PLA2 activity may, in part, account for the higher generation of LTB4 by RA PMNL; NSAIAs may be capable of modulating this abnormality; and Clotrimazole may affect the clinical or laboratory data of RA patients already on treatment with NSAIA.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acids; Arthritis, Rheumatoid; Calcimycin; Clotrimazole; Humans; Imidazoles; Leukotriene B4; Neutrophils; Phospholipases A; Phospholipases A2

In a double blind noncrossover study, dietary supplementation with fish oil (18 g/day), was compared with an olive oil supplement over a 12-week period in patients with rheumatoid arthritis receiving established conventional therapies. An improvement in tender joint score and grip strength was seen at 12 weeks in the fish oil treated group but not in the olive oil treated group. The more subjective measures of mean duration of morning stiffness and analogue pain score improved to a similar extent in both groups, although statistical significance was only achieved in paired analyses in the olive oil treated group. Production of leukotriene B4 by isolated neutrophils stimulated in vitro was reduced by 30% in the fish oil treated group and unchanged in the olive oil treated group.

Topics: Adult; Aged; Arthritis, Rheumatoid; Dietary Fats, Unsaturated; Double-Blind Method; Female; Fish Oils; Food, Fortified; Humans; Leukotriene B4; Male; Middle Aged; Neutrophils; Pain Measurement; Random Allocation; Triglycerides

to determine the efficacy of fish-oil dietary supplements in active rheumatoid arthritis and their effect on neutrophil leukotriene levels.. nonrandomized, double-blinded, placebo-controlled, crossover trial with 14-week treatment periods and 4-week washout periods.. academic medical center, referral-based rheumatology clinic.. forty volunteers with active, definite, or classical rheumatoid arthritis. Five patients dropped out, and two were removed for noncompliance.. treatment with nonsteroidal anti-inflammatory drugs, slow-acting antirheumatic drugs, and prednisone was continued. Twenty-one patients began with a daily dosage of 2.7 g of eicosapaentanic acid and 1.8 g of docosahexenoic acid given in 15 MAX-EPA capsules (R.P. Scherer, Clearwater, Florida), and 19 began with identical-appearing placebos. The background diet was unchanged.. the following results favored fish oil placebo after 14 weeks: mean time to onset of fatigue improved by 156 minutes (95% confidence interval, 1.2 to 311.0 minutes), and number of tender joints decreased by 3.5 (95% Cl, -6.0 to -1.0). Other clinical measures favored fish oil as well but did reach statistical significance. Neutrophil leukotriene B4 production was correlated with the decrease in number of tender joints (Spearman rank correlation r=0.53; p less than 0.05). There were no statistically significant differences in hemoglobin level, sedimentation rate, or presence of rheumatoid factor or in patient-reported adverse effects. An effect from the fish oil persisted beyond the 4-week washout period.. fish-oil ingestion results in subjective alleviation of active rheumatoid arthritis and reduction in neutrophil leukotriene B4 production. Further studies are needed to elucidate mechanisms of action and optimal dose and duration of fish-oil supplementation.

Topics: Adult; Aged; Arthritis, Rheumatoid; Clinical Trials as Topic; Diet; Double-Blind Method; Eicosapentaenoic Acid; Female; Fish Oils; Humans; Leukotriene B4; Male; Middle Aged; Neutrophils

Rheumatoid arthritis (RA)-associated lung disease (LD) associates with significantly increased morbidity and mortality. Although oxidative stress plays an important role in the inflammatory responses in other forms of lung disease, minimal work has evaluated its role in RA-LD. The current work examines the relationship between the anti-oxidant HDL-associated enzyme paraoxonase-1 (PON1), the PON1 Q192R polymorphism, and a targeted oxylipin panel with RA-LD.. This study was conducted as a retrospective chart review of a longitudinal single-center cohort of 250 RA patients. CT scans of the chest were reviewed by the interpreting radiologist and classified as small airways disease (SAD), interstitial lung disease (ILD), and bronchiectasis. PON1 activity was measured by its lactonase, arylesterase, and paraoxonase functions. The PON1 Q192R polymorphism and a targeted lipidomics panel were performed as previously reported.. 43.2% of the 250 RA patient cohort (n = 108) had available CT scans, including 48 patients (44.4%) with SAD, 27 patients (25.0%) with bronchiectasis, and 16 patients (14.8%) with ILD. Patients with SAD had significantly lower baseline PON1 activity by its arylesterase, and lactonase functions, as well as higher 15-HETE, LTB4, and PGE2 levels compared to those without SAD. These predictors of SAD remained significant after multivariate analysis including known risk factors for RA-LD. Suppressed PON1 activity also correlated with higher levels of 15-HETE and 12-HETE.. In a single-center RA cohort, suppressed baseline PON1 activity and elevation in the oxylipins 15-HETE, LTB4, and PGE2 predicted the presence of RA-SAD in longitudinal follow-up. Key Points • Small airways disease (SAD) was present in 44.4% of this rheumatoid arthritis (RA) cohort. • Patients with SAD had significantly lower baseline PON1 activity, as well as higher levels of the oxylipins 15-HETE, LTB4, and PGE2 levels compared to those without SAD. • Further work is warranted to confirm these findings and further define the role of PON1 and lipid oxidation in RA lung disease.

Topics: Arthritis, Rheumatoid; Aryldialkylphosphatase; Bronchiectasis; Dinoprostone; Humans; Leukotriene B4; Lung Diseases; Oxylipins; Retrospective Studies

Leukotriene B4 (LTB4) is a potent chemoattractant that can recruit and activate immune cells such as neutrophils, eosinophils, and monocytes to sites of inflammation. Excessive production of LTB4 has been linked to acute and chronic inflammatory diseases, including asthma, rheumatoid arthritis, and psoriasis. Inhibiting the binding of LTB4 to its receptors, BLT1 and BLT2, is a potential strategy for treating these conditions. While several BLT1 antagonists have been developed for clinical trials, most have failed due to efficacy and safety issues. Therefore, discovering selective BLT2 antagonists could improve our understanding of the distinct functions of BLT1 and BLT2 receptors and their pharmacological implications. In this study, we aimed to discover novel BLT2 antagonists by synthesizing a series of biphenyl analogues based on a BLT2 selective agonist, CAY10583. Among the synthesized compounds, 15b was found to selectively inhibit the chemotaxis of CHO-BLT2 cells with an IC

Topics: Animals; Arthritis, Rheumatoid; Asthma; CHO Cells; Cricetinae; Inflammation; Leukotriene B4; Mice; Receptors, Leukotriene B4

Rheumatoid arthritis is characterized by progressive joint inflammation and affects ~1% of the human population. We noted single-nucleotide polymorphisms (SNPs) in the apoptotic cell-engulfment genes ELMO1, DOCK2, and RAC1 linked to rheumatoid arthritis. As ELMO1 promotes cytoskeletal reorganization during engulfment, we hypothesized that ELMO1 loss would worsen inflammatory arthritis. Surprisingly, Elmo1-deficient mice showed reduced joint inflammation in acute and chronic arthritis models. Genetic and cell-biology studies revealed that ELMO1 associates with receptors linked to neutrophil function in arthritis and regulates activation and early neutrophil recruitment to the joints, without general inhibition of inflammatory responses. Further, neutrophils from the peripheral blood of human donors that carry the SNP in ELMO1 associated with arthritis display increased migratory capacity, whereas ELMO1 knockdown reduces human neutrophil migration to chemokines linked to arthritis. These data identify 'noncanonical' roles for ELMO1 as an important cytoplasmic regulator of specific neutrophil receptors and promoter of arthritis.

Topics: Adaptor Proteins, Signal Transducing; Animals; Apoptosis; Arthritis, Experimental; Arthritis, Rheumatoid; Chemotaxis; Collagen; Complement C5a; Cytoplasm; Disease Models, Animal; Female; Gene Expression Profiling; Healthy Volunteers; Humans; Intravital Microscopy; Joints; Leukotriene B4; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Polymorphism, Single Nucleotide; Proteomics; Severity of Illness Index; Signal Transduction; Time-Lapse Imaging

G Protein Signaling Modulator-3 (GPSM3) is a leukocyte-specific regulator of G protein-coupled receptors (GPCRs), which binds inactivated Gαi·GDP subunits and precludes their reassociation with Gβγ subunits. GPSM3 deficiency protects mice from inflammatory arthritis and, in humans, GPSM3 single-nucleotide polymorphisms (SNPs) are inversely associated with the risk of rheumatoid arthritis development; recently, these polymorphisms were linked to one particular SNP (rs204989) that decreases GPSM3 transcript abundance. However, the precise role of GPSM3 in leukocyte biology is unknown. Here, we show that GPSM3 is induced in the human promyelocytic leukemia NB4 cell line following retinoic acid treatment, which differentiates this cell line into a model of neutrophil physiology (NB4*). Reducing GPSM3 expression in NB4* cells, akin to the effect ascribed to the rs204989 C>T transition, disrupts cellular migration toward leukotriene B4 (LTB4) and (to a lesser extent) interleukin-8 (a.k.a. IL-8 or CXCL8), but not migration toward formylated peptides (fMLP). As the chemoattractants LTB4 and CXCL8 are involved in recruitment of neutrophils to the arthritic joint, our results suggest that the arthritis-protective GPSM3 SNP rs204989 may act to decrease neutrophil chemoattractant responsiveness.

Topics: Arthritis, Rheumatoid; Cell Line, Tumor; Chemotaxis, Leukocyte; Guanine Nucleotide Dissociation Inhibitors; Humans; Interleukin-8; Leukopoiesis; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Polymorphism, Single Nucleotide; Tretinoin

Arachidonic acid metabolites, such as leukotriene B4 (LTB4), are known to play an important role in pathogenesis of rheumatoid arthritis (RA). Apart from leukocytes, RA synovial fibroblasts (RASF) produce a broad array of inflammatory mediators to recruit, retain and activate immune cells and resident mesenchymal cells in the joints to promote ongoing inflammation and tissue destruction. To determine how LTB4 may contribute to this process, RASF was cultured from synovial tissues collected from RA patients undergoing total knee replacement. The level of LTB4 in culture medium was determined using ELISA, and expression of LTB4 receptors (BLT1 and BLT2) by RT-PCR. In the presence of exogenous LTB4, mRNA and protein levels of tumor necrosis factor-alpha (TNFalpha) and interleukin 1beta (IL1beta) were determined by real-time PCR and ELISA. Furthermore, we examined the effects of leukotrienes synthesis inhibitors, MK886 and bestatin, on mRNA and protein levels of TNFalpha and IL1beta in RASF. We found that LTB4 was present at a low concentration in the culture medium of RASF, and the major LTB4 receptor expressed in RASF was BLT2. LTB4 synthesis was activated by treatment with LIT (LPS, ionomycin and thapsogargin), and suppressed by MK886 and bestatin. Exogenous LTB4 remarkably increased the expression of TNFalpha and IL1beta at both the mRNA level and the protein level. In contrast, MK886 and bestatin significantly inhibited their expression. These data suggested that LTB4 contributed to RA by regulating the expression of TNFalpha and IL1beta in RASF. BLT2 was probably the major receptor mediating such effects.

Topics: Arthritis, Rheumatoid; Fibroblasts; Humans; Inflammation Mediators; Interleukin-1beta; Leukocytes; Leukotriene B4; Lipopolysaccharides; Receptors, Leukotriene B4; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Synovial Membrane; Tumor Necrosis Factor-alpha

Our previous study showed that Leukotriene B4 can directly stimulate osteoclast differentiation independent of RANKL. In order to determine whether Leukotriene B4 could indirectly stimulate human osteoclast differentiation through increasing RANKL expression of rheumatoid arthritis fibroblast-like synoviocytes, we utilize the coculture model of rheumatoid arthritis fibroblast-like synoviocytes and monocyte, which were stimulated in the presence of 2.5 ng/ml M-CSF in the control group, 2.5 ng/ml M-CSF+10(-8)M LTB4 in the experimental group a, and 2.5 ng/ml M-CSF+10(-8)M LTB4+100 ng/ml OPG in the experimental group b. After culture for 3 weeks, the number of multinucleated TRAP staining positive osteoclast-like cells stained with TRAP was counted to evaluate the differentiation effect in each group. There was almost no osteoclast-like cell in the control group and the experimental group b. There were many osteoclast-like cells in the experimental group a. These results indicated that Leukotriene B4 is capable of inducing osteoclast differentiation by a RANKL-dependent mechanism.

Topics: Arthritis, Rheumatoid; Bone Resorption; Cell Differentiation; Cells, Cultured; Coculture Techniques; Fibroblasts; Humans; Leukotriene B4; Macrophage Colony-Stimulating Factor; Monocytes; Osteoclasts; Osteogenesis; RANK Ligand; Recombinant Proteins; Synovial Membrane

Lipid mediators derived from arachidonic acid through the cyclooxygenase and lipoxygenase pathways are known to be important mediators of inflammation. Studies in mouse models demonstrated an important role for the high-affinity leukotriene B(4) receptor BLT1 in arthritis, atherosclerosis, and asthma. BLT2, a low-affinity leukotriene B(4) receptor, was also shown to be a high-affinity receptor for cyclooxygenase-1 derived 12(S)-hydroxyheptadeca-5Z, 8E, 10E-trienoic acid. However, its biochemical activities and physiological roles remain unknown. In this study, we developed mice deficient in BLT2 by targeted disruption. The BLT2(-/-) mice developed normally, and analysis of immune cells showed that disruption of BLT2 did not alter BLT1 expression or function. Mast cells from the C57BL/6 mice but not from the BLT2(-/-) mice showed intracellular calcium mobilization in response to 12(S)-hydroxyheptadeca-5Z, 8E, 10E-trienoic acid. In an autoantibody-induced inflammatory arthritis model, the BLT2(-/-) mice showed reduced incidence and severity of disease, including protection from bone and cartilage loss. Reciprocal bone marrow transplant experiments identified that loss of BLT2 expression on a bone marrow-derived cell lineage offers protection against severe disease. Thus, BLT2, a unique receptor for 5-lipoxygenase- and cyclooxygenase-1-derived lipid mediators, represents a novel target for therapies directed at treating inflammation associated with arthritis.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Marrow Cells; Chemotaxis, Leukocyte; Humans; Inflammation Mediators; Knee Joint; Leukotriene B4; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Neutrophils; Receptors, Leukotriene B4

To determine the effect of combinations of cyclooxygenase (COX) inhibitors and inhibitors of leukotriene (LT) syntheses on collagen induced arthritis (CIA) in mice.. The CIA model was evaluated for the presence of eicosanoids in the paw tissue. Several selective cyclooxygenase 2 (COX-2) inhibitors or non-selective non-steroidal anti inflammatory drugs (NSAIDs) were evaluated alone or in combination with leukotriene (LT) synthesis inhibitors in the CIA model.. Arthritic paw tissue showed increased levels of prostaglandins and leukotrienes in comparison to normal paws. Analysis of mRNA levels indicated the inducible form of the COX-2 enzyme to be the source of prostaglandins. NSAIDs, COX-2 or leukotriene synthesis inhibitors administered alone in CIA decreased severity but had little effect on disease incidence. However, the combination of selective COX-2 inhibitors with leukotriene synthesis inhibitors produced significant decreases in both incidence and severity, suggesting an additive or synergistic effect. This effect was reversible with removal of drug. Little decrease in incidence was observed with the NSAID/5-LO inhibitor combinations.. These results suggest that the induction of the disease in CIA is mediated by products of the COX-2 enzyme and LTB4 production, and that blockade of both pathways is required to prevent CIA.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Arachidonate 5-Lipoxygenase; Arthritis, Experimental; Arthritis, Rheumatoid; Celecoxib; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Epoxide Hydrolases; Humans; Hydroxyurea; Leukotriene B4; Leukotrienes; Male; Mice; Mice, Inbred DBA; Prostaglandins; Pyrazoles; RNA, Messenger; Sulfonamides

The trafficking of immune cells to inflamed joints is the hallmark of rheumatoid arthritis. It has been known for years that neutrophils are abundant in the rheumatoid joints and have the potential to inflict tissue damage by the secretion of oxidants and proteases; however, the crucial role of neutrophil trafficking to the joints has only been demonstrated in recent years using transgenic mice and animal models of the disease. This finding opens the door to potential therapies based on inhibition of neutrophil trafficking. In this issue of the European Journal of Immunology, a study reports the use of antisense RNA to knock down the expression of cytosolic phospholipase A2alpha in mice. This has a major effect on neutrophil trafficking into inflamed joints and reverses the inflammatory swelling and tissue damage in the animal model used. This puts cytosolic phospholipase A2alpha, alongside its product leukotriene B4, on the list of potential targets for reducing cell trafficking to the joint in chronic inflammatory diseases like rheumatoid arthritis.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Cell Movement; Disease Models, Animal; Group IV Phospholipases A2; Joints; Leukotriene B4; Mice; Neutrophil Infiltration; Neutrophils; RNA, Antisense

The TNF superfamily member LIGHT has a T-cell co-stimulatory role and has previously been associated with inflammation and autoimmunity. To investigate its role in rheumatoid arthritis (RA), a disease where activated T cells contribute in a prominent way, we have analysed the expression of LIGHT and its receptors in RA and analysed its effects on synovial fibroblasts in vitro.. The expression of LIGHT was measured in synovial tissues and fluids and the receptors of LIGHT were detected on synovial fibroblasts derived from patients with RA and osteoarthritis (OA). The effects of recombinant LIGHT on the production of proinflammatory cytokines and proteases and on the apoptosis of synovial fibroblasts was assessed.. LIGHT mRNA was present in synovial tissues of patients with RA but not with OA. Correspondingly, soluble LIGHT protein could be detected in RA synovial fluid samples at much higher levels than in synovial fluid from patients with OA. Immunohistochemical detection of LIGHT and analysis of synovial fluid cells by flow cytometry revealed CD4 T cells as the major source of LIGHT in the rheumatoid joint. Synovial fibroblasts from RA patients were found to express the LIGHT receptors HVEM and LTbetaR. Recombinant LIGHT induced RA synovial fibroblasts to upregulate MMP-9 mRNA, CD54 and IL-6 in an NF-kappaB-dependent fashion. In vitro, exposure of cultured synovial fibroblasts to LIGHT reduced FAS-mediated apoptosis significantly, without affecting the rate of spontaneous apoptosis.. The results provide evidence for a novel T-cell-dependent activation of synovial fibroblasts by LIGHT in joints of patients with RA, contributing to an inflammatory and destructive phenotype.

Topics: Aged; Apoptosis; Arthritis, Rheumatoid; CD4-Positive T-Lymphocytes; Cell Proliferation; Cell Survival; Cells, Cultured; Female; Fibroblasts; Flow Cytometry; Humans; Immunohistochemistry; Intercellular Adhesion Molecule-1; Interleukin-6; Leukotriene B4; Male; Matrix Metalloproteinase 9; Middle Aged; NF-kappa B; Osteoarthritis; Receptors, Tumor Necrosis Factor, Member 14; Recombinant Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Statistics, Nonparametric; Synovial Fluid; Synovial Membrane; Tumor Necrosis Factor Ligand Superfamily Member 14

To investigate quantification of expression of LTB4 inducing IL-1beta and TNF-alpha at mRNA level in synovial membrane cells of rheumatoid arthritis.. Primary cultured synovial cells from RA patients were treated with exogenous LTB4, MK-886 (inhibitor of 5-lipoxygenase activating protein) and Bestatin(inhibitor of leukotriene A4 hydrolase) in the presence of LIT respectively, expressions of TNF-alpha and IL-1beta were detected at mRNA level by Real-time Quantitative PCR.. Expressions of basic TNF-alpha (TNF-alpha/GAPDH) and IL-beta (IL-beta/GAPDH) at mRNA level in primary cultured synovial cells were 0.02 +/- 0.00 and 0.16 +/- 0.01 respectively. LTB4 (10(-9) mol/L-10(-8) mol/L) was shown to induce dose-dependent increase of mRNA expression of TNF-alpha. (7-15 times) and IL-1beta (1 time) , endogenous product of LTB4 by LIT significantly increased mRNA expressions of TNF-alpha (145 times) and IL-1beta (12 times) respectively. LIT-treated synoviocytes with addition of MK-886 (5-LOX exciting protein FLAP inhibitor) (1-10 micromol/L) were inhibited to secrete LTB4 dose-dependently, following the markedly down-regulated expressions of TNF-alpha (15%-66%) and IL-1beta (41%-71%) at mRNA level . Bestatin(100 mg/L) could also remarkably diminish LTB4-induced mRNA expressions of TNF-alpha(86%) and IL-1beta (79%).. LTB4 of synovial membrance cells in rheumatoid arthritis could induce expressions of TNF-alpha and IL-1beta at mRNA level, and their expression at mRNA level had been quantified successfully. It is a beneficial help to quantify all kinds of cytokines in methodology.

Topics: Arthritis, Rheumatoid; Cells, Cultured; Gene Expression; Humans; Indoles; Interleukin-1beta; Leukotriene B4; Polymerase Chain Reaction; RNA, Messenger; Synovial Membrane; Tumor Necrosis Factor-alpha

IL-18 expression and functional activity have been associated with a range of autoimmune diseases. However, the precise mechanism by which IL-18 induces such pathology remains unclear. In this study we provide direct evidence that IL-18 activates neutrophils via TNF-alpha induction, which drives the production of leukotriene B(4) (LTB(4)), which in turn leads to neutrophil accumulation and subsequent local inflammation. rIL-18 administered i.p. resulted in the local synthesis of LTB(4) and a rapid influx of neutrophils into the peritoneal cavity, which could be effectively blocked by the LTB(4) synthesis inhibitor MK-886 (MK) or its receptor antagonist CP-105,696. IL-18-induced neutrophils recruitment and LTB(4) production could also be blocked by a neutralizing anti-TNF-alpha Ab. In addition, IL-18 failed to induce neutrophil accumulation in vivo in TNFRp55(-/-) mice. In an IL-18-dependent murine collagen-induced arthritis model, administration of MK significantly inhibited disease severity and reduced articular inflammation and joint destruction. Furthermore, MK-886-treated mice also displayed suppressed proinflammatory cytokine production in response to type II collagen in vitro. Finally, we showed that IL-18-activated human peripheral blood neutrophils produced significant amounts of LTB(4) that were effectively blocked by the MK. Together, these findings provide a novel mechanism whereby IL-18 can promote inflammatory diseases.

Topics: Adjuvants, Immunologic; Administration, Oral; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Cells, Cultured; Chemotaxis, Leukocyte; Collagen Type II; Humans; Indoles; Inflammation Mediators; Injections, Intradermal; Injections, Intraperitoneal; Interleukin-18; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Knockout; Neutrophil Infiltration; Neutrophils; Severity of Illness Index; Tumor Necrosis Factor-alpha

Rheumatoid arthritis (RA) is a chronic polyarticular joint disease associated with massive synovial proliferation, inflammation, and angiogenesis. PPAR-gamma ligands, both 15-deoxy-Delta(12,14)-prostaglandin J2 (15d- PGJ2) and troglitazone (TRO), can inhibit the growth of RA synoviocytes in vitro, and suppress the chronic inflammation of adjuvant-induced arthritis in rats, but the potency of 15d-PGJ2 is higher than TRO. Prostaglandin (PG) E2 plays important roles in joint erosion and synovial inflammation. In the present study, 15d-PGJ2, but not TRO and other prostanoids, suppressed interleukin (IL)-1beta-induced PGE2 synthesis in rheumatoid synovial fibroblasts (RSFs) through the inhibition of cyclooxygenase (COX-2) and cytosolic phospholipase A2 (cPLA2) expression. Furthermore, the inhibition was not affected by pretreatment with anti-PPAR-gamma antibody. It means that this anti-inflammatory effect of 15d-PGJ2 for PG synthesis may be independent of PPAR-gamma and 15d-PGJ2 is a key regulator of negative feedback of the arachidonate cascade on the COX pathway. These findings provide new insight into the feedback mechanism of the arachidonate cascade.

Topics: Arachidonic Acid; Arthritis, Rheumatoid; Chromans; Cyclooxygenase 2; Cysteine; Dinoprostone; Feedback; Humans; Isoenzymes; Leukotriene Antagonists; Leukotriene B4; Leukotrienes; Membrane Proteins; Prostaglandin D2; Prostaglandin-Endoperoxide Synthases; Receptors, Cytoplasmic and Nuclear; Synovial Membrane; Thiazoles; Thiazolidinediones; Transcription Factors; Troglitazone

Leukotriene B(4) (LTB(4)) is a potent chemoattractant and activator of both granulocytes and macrophages. The actions of LTB(4) appear to be mediated by a specific G protein-coupled receptor (GPCR) BLT1, originally termed BLT (Yokomizo, T., T. Izumi, K. Chang, Y. Takuwa, and T. Shimizu. 1997. Nature. 387:620-624). Here, we report the molecular cloning of a novel GPCR for LTB(4), designated BLT2, which binds LTB(4) with a Kd value of 23 nM compared with 1.1 nM for BLT1, but still efficiently transduces intracellular signaling. BLT2 is highly homologous to BLT1, with an amino acid identity of 45.2%, and its open reading frame is located in the promoter region of the BLT1 gene. BLT2 is expressed ubiquitously, in contrast to BLT1, which is expressed predominantly in leukocytes. Chinese hamster ovary cells expressing BLT2 exhibit LTB(4)-induced chemotaxis, calcium mobilization, and pertussis toxin-insensitive inhibition of adenylyl cyclase. Several BLT1 antagonists, including U 75302, failed to inhibit LTB(4) binding to BLT2. Thus, BLT2 is a pharmacologically distinct receptor for LTB(4), and may mediate cellular functions in tissues other than leukocytes. BLT2 provides a novel target for antiinflammatory therapy and promises to expand our knowledge of LTB(4) function. The location of the gene suggests shared transcriptional regulation of these two receptors.

Topics: Amino Acid Sequence; Animals; Arthritis, Rheumatoid; Asthma; Base Sequence; Cell Line; CHO Cells; Cloning, Molecular; Cricetinae; DNA, Complementary; Humans; Inflammatory Bowel Diseases; Leukotriene B4; Mice; Molecular Sequence Data; Psoriasis; Receptors, Leukotriene B4; Renal Insufficiency; Sequence Homology, Amino Acid; Signal Transduction; Tissue Distribution

Omega-3 (omega-3) fatty acid rich-fish oil (FO) and vitamin E (vit-E) may delay the progress of certain autoimmune diseases. The present study examined the mechanism of action of omega-3 and omega-6 lipids and vit-E on the serum cytokines and lipid mediators in autoimmune-prone MRL/lpr mice (a model for rheumatoid arthritis, RA). The lpr (lymphoproliferative) gene is overexpressed in these mice causing extensive lymphoproliferation, lupus-like symptoms and accelerated aging.. Weanling female MRL/lpr and congenic control MRL/++ mice were fed 10% corn oil (CO, omega6) or FO-based semipurified diets containing two levels of vitamin E (vit-E-75, I.U. and vit-E-500 I.U./Kg diet) for four months. At the end of the experiment, serum anti-DNA antibodies, cytokines and lipid mediators levels were determined.. The appearance of enlarged lymph nodes was delayed in the mice fed FO, and the FO-500 IU vit-E diet offered further protection against enlargement of lymph nodes. The MRL/lpr mice exhibited significantly higher levels of serum anti-dsDNA antibodies. The FO-fed mice had significantly lower serum IL-6, IL-10, IL-12, TNF-alpha, PGE2, TXB2 and LTB4 levels compared with CO-fed mice. In mice fed 500 IU vit-E diets, the serum IL-6, IL-10, IL-12 and TNF-alpha levels were significantly lower and serum IL-1beta was significantly higher compared to 75 IU-vit-E-fed mice in CO/FO or both. The levels of anti-DNA antibodies, IL-4, IL-6, TNF-alpha, IL-10 and IL-12 were higher in the sera of MRL/lpr mice. The FO diet lowered the levels of these cytokines (except IL-4) and lipid mediators. Adding 500 IU of vit-E to the FO diet further lowered the levels of IL-6, IL-10, IL-12, and TNF-alpha.. It is clear from our observations that the beneficial effects of FO can be enhanced by the addition of 500 IU of vit-E in the diet. The FO diet containing 500 IU of vit-E may specifically modulate the levels of IL-6, IL-10, IL-12 and TNF-alpha and thereby may delay the onset of autoimmunity in the MRL/lpr mouse model. The observations from this study may form a basis for selective nutrition intervention based on specific fatty acids and antioxidants in delaying the progress of RA.

Topics: Animals; Antibodies, Antinuclear; Arthritis, Rheumatoid; Body Weight; Cytokines; Dietary Fats, Unsaturated; Dinoprostone; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Female; Interleukins; Kidney; Leukotriene B4; Mice; Thromboxane B2; Tumor Necrosis Factor-alpha; Vitamin E; Weaning

The possible association of leukotriene B4 (LTB4)-like activity with the development of active rheumatoid arthritis was studied in 25 children with the disease and in 15 normal subjects. Serum LTB4-like activity was found to be significantly higher in the active stage of the disease when compared with the values obtained from patients during the inactive stage and from healthy children. No correlation was found between LTB4-activity and other laboratory parameters, e.g. haemoglobin level, white cell count and erythrocyte sedimentation rate.

Topics: Adolescent; Anti-Inflammatory Agents; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Aspirin; Blood Sedimentation; Case-Control Studies; Child; Child, Preschool; Cyclooxygenase Inhibitors; Female; Hemoglobins; Humans; Indomethacin; Leukocyte Count; Leukotriene B4; Lipoxygenase Inhibitors; Male; Prednisolone

Lipids in the synovial fluid of patients with active rheumatoid arthritis are elevated compared to normal synovial fluid and that of other inflammatory arthropathies. Various assumptions about the role of these lipids have been made. This study offers evidence that these lipids may contribute to the synovitis in rheumatoid arthritis through participation in the arachidonic pathway within the joint space. Phospholipase A2 activity, phospholipids, prostaglandin E2, and leukotriene B4 have been correlated in the synovial fluid and plasma of untreated rheumatoid patients and compared with that of patients with osteoarthritis.

Topics: Arthritis, Rheumatoid; Case-Control Studies; Dinoprostone; Humans; Leukotriene B4; Lipoproteins; Male; Middle Aged; Osteoarthritis; Phospholipases A; Phospholipases A2; Phospholipids; Synovial Fluid; Synovitis

Clinical and experimental evidence suggests that arachidonic acid metabolism through lipoxygenase and cyclooxygenase pathways may play an important role in the pathogenesis of both inflammatory and degenerative joint diseases. The aim of the present paper was to measure the levels of different arachidonate metabolites in arthrosis or rheumatoid joint effusions.. We studied synovial fluids from 22 patients with arthrosis and 8 patients with rheumatoid arthritis. The levels of TxB2, 6-keto-PGF1 alpha LTB4 and LTC4 were measured by radioimmunoassay.. The levels of the different arachidonate metabolites were higher in patients with rheumatoid arthritis than in those with arthrosis and the differences were always statistically significant, except for TxB2 values. Furthermore, in patients with arthrosis the levels of such metabolites were not significantly correlated with one another, with the exception of LTB4 and LTC4 values, while in patients with rheumatoid arthritis these levels were directly and significantly correlated.. In inflammatory joint disease levels of arachidonate metabolites are higher and more directly correlated with one another than in degenerative joint disease. Our data may explain the better efficacy of non-steroidal anti-inflammatory drugs in patients with arthrosis than in those with rheumatoid arthritis and the frequent necessity for steroidal treatment in this last condition.

Topics: 6-Ketoprostaglandin F1 alpha; Arachidonic Acid; Arthritis, Rheumatoid; Humans; Joint Diseases; Leukotriene B4; Leukotriene C4; Radioimmunoassay; Synovial Fluid; Thromboxane B2

The synthesis of leukotriene B4 by A23187-stimulated rat peritoneal leukocytes was studied in the presence of 0.1% normal human serum, serum from patients treated with NSAIDs for either an inflammatory (rheumatoid arthritis, RA) or a non-inflammatory condition (lumbar disc protrusion, LDP), and serum from RA patients drawn one week after withdrawal from NSAID treatment. The capacity for LTB4 synthesis was significantly lower in the presence of serum from NSAID treated patients: thirty per cent less than observed in presence of normal serum in the RA group, and fifty per cent in the LDP group. When NSAIDs were withdrawn from RA patients, the LTB4 production in presence of serum increased, but was not completely normalized after one week. These results indicate that NSAID treatment may down-regulate the capacity for leukotriene synthesis by an indirect effect.

Topics: Adult; Aged; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Blood; Female; Humans; Leukocytes; Leukotriene B4; Male; Middle Aged; Rats; Rats, Sprague-Dawley; Spinal Diseases

The present study was designed to compare peripheral blood neutrophil migration and leukotriene (LT) release between patients with rheumatoid arthritis (RA) and healthy controls and to correlate the neutrophil functions with clinical disease activity. Nineteen patients with moderately active RA and 19 age and sex matched healthy volunteers participated in this study. Isolated peripheral blood neutrophils from RA patients released equal amounts of LTB4 but their random migration was enhanced as compared with neutrophils from healthy controls. LTB4 release in whole blood was significantly lower in samples from RA patients than in those from the healthy volunteers (13.5 +/- 1.4 and 19.1 +/- 1.4 ng/10(6) neutrophils respectively; P < 0.001). LTB4 release from isolated RA neutrophils correlated with the levels of C-reactive protein, duration of morning stiffness and Ritchie articular swelling index. Concentrations of hyaluronate, cyclic AMP and 13, 14-dihydro-15-keto prostaglandin were not different between patients with RA and healthy volunteers. Neither was there any difference in TXB2 production by platelets during blood clotting. In conclusion, peripheral blood neutrophils of RA patients seem to be primed and/or activated as their random migration is enhanced as compared with those of healthy volunteers. In RA, LTB4 release from peripheral blood neutrophils seems to reflect the clinical activity of the disease. However, RA neutrophils released smaller (in whole blood) or equal (isolated cells) amount of LTB4 as compared with the respective controls. These contradictory findings suggest that LTB4 release from peripheral blood neutrophils has no major role in the regulation of disease activity in rheumatoid arthritis.

Topics: Adolescent; Adult; Aged; Arthritis, Rheumatoid; Case-Control Studies; Cell Movement; Female; Humans; In Vitro Techniques; Leukotriene B4; Male; Middle Aged; Neutrophil Activation; Neutrophils

Leukotriene B4 (LTB4) is a product of the 5-lipoxygenase pathway of arachidonic acid metabolism. LTB4 is a potent chemotactic factor for neutrophils and has been postulated to play an important role in a variety of pathological conditions including rheumatoid arthritis (RA), psoriasis, and inflammatory bowel disease. The role of LTB4 in such diseases has not yet been defined but in this paper we provide direct evidence that LTB4 plays a critical role in a murine model of RA. CP-105,696, (+)-1-(3S,4R)-[3-(4-phenylbenzyl)- 4-hydroxychroman-7-yl]cyclopentane carboxylic acid, is an LTB4 receptor antagonist that inhibits LTB4 binding to human neutrophil membranes with an IC50 of 3.7 nM and inhibits LTB4-induced chemotaxis of these cells with an IC50 of 5.2 nM. CP-105,696 inhibits LTB4-induced neutrophil influx in mouse skin when administered orally with an ED50 of 4.2 mg/kg. CP-105,696 had a dramatic effect on both the clinical symptoms and histological changes of murine collagen-induced arthritis when administered at doses of 0.3-10 mg/kg. Inhibition was not associated with suppression of the humoral immune response to collagen and was equally effective if drug treatment was commenced just prior to the onset of arthritis or throughout the experiment. These results suggest that LTB4 receptor antagonists may be effective therapeutic agents for the treatment of RA.

Topics: Animals; Arthritis, Rheumatoid; Benzopyrans; Binding, Competitive; Carboxylic Acids; Chemotaxis, Leukocyte; Dose-Response Relationship, Drug; Humans; Joints; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Mice, Inbred DBA; Neutrophils; Receptors, Leukotriene B4

Human blood polymorphonuclear cells (PMN) from seven patients with active rheumatoid arthritis (RA) were compared for their capacities to produce leukotrienes ex vivo before (D0) and 24 hr (D1) after glucocorticoid pulse therapy. The present study shows for the first time that endogenous arachidonic acid metabolism via 5-lipoxygenase pathway is significantly increased after glucocorticoid administration, leading to increased generation of the unstable precursor leukotriene A4 (LTA4) followed by predominant non-enzymatic LTA4 opening and leukotriene B4 (LTB4) omega-hydroxylation pathway. These results are unexpected since usually glucocorticoids are usually thought to decrease inflammatory mediator biosynthesis and, moreover, they work to the detriment of the clinical improvement of the patient. The results are discussed in terms of product inactivation and cellular cooperation with monocytes and endothelial cells.

Topics: Arachidonate 5-Lipoxygenase; Arachidonic Acid; Arthritis, Rheumatoid; Female; Glucocorticoids; Humans; Leukotriene A4; Leukotriene B4; Male; Middle Aged; Neutrophils

Twelve patients suffering from rheumatoid arthritis and having swollen knees were treated with 1.1 g/day of sodium naproxen administered in one dose, daily for 5 days. The 72-h wash-out period was verified by the absence of any nonsteroidal anti-inflammatory drug using a HPLC screening. Blood and synovial fluid samples were drawn just before treatment and 24 h after the last dose. Eicosanoids (PGE2, 6-keto-PGF1 alpha, TXB2, LTB4, LTC4) in synovial fluid were determined by immunoenzymatic assays. In plasma and synovial fluid, hyaluronic acid was assayed by radiometric assay and sodium naproxen by HPLC. Free drug was determined by equilibrium dialysis. Statistical analysis used nonparametric tests. Pain relief (evaluated on a visual scale), morning stiffness, and scores on the Lee and Ritchie indices all decreased significantly, as did PGE2 and LTB4 concentrations. The decrease in 6-keto-PGF1 alpha and TXB2 was not significant. No significant change was found for LTC4 and hyaluronic acid. Total concentrations of sodium naproxen were equivalent in plasma (16.1 micrograms.ml-1) and synovial fluid (18.9 micrograms.ml-1). Free fractions were significantly higher in synovial fluid (0.14%) than in plasma (0.11%), as shown by binding of the drug to human serum albumin, at various protein concentrations. Interestingly, the clinical efficacy, as shown by decreases in morning stiffness and in the Lee index score, correlated with the free concentration of naproxen in synovial fluid.

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Arthritis, Rheumatoid; Biomarkers; Chromatography, High Pressure Liquid; Dinoprostone; Female; Humans; Hyaluronic Acid; Immunoenzyme Techniques; Knee Joint; Leukotriene B4; Male; Middle Aged; Naproxen; Protein Binding; Synovial Fluid; Thromboxane B2

We examined the role of Leukotrien B4 (LTB4) in the production of Interleukin-1 beta (IL-1 beta) by rheumatoid synovial cells since a substantial amount of LTB4 has been detected in the synovial fluid from patients with rheumatoid arthritis. The production of IL-1 beta was augmented by LTB4 at concentrations of 10(-9) to 10(-8) M. Furthermore, LTB4 showed the additive effect on the IL-1 beta production with interferon-gamma but not with lipopolysaccharide. These results suggest that LTB4 in cooperation with certain cytokines might play a pivotal role in the IL-1 beta production by rheumatoid synovial cells in vivo.

Topics: Arthritis, Rheumatoid; Cells, Cultured; Dose-Response Relationship, Drug; Humans; Interleukin-1; Leukotriene B4; Lipopolysaccharides; Osmolar Concentration; Synovial Membrane

We have examined the ability of interleukin-4 (IL-4), interleukin-10 (IL-10) and interleukin-1 receptor antagonist protein (IL-1ra) to regulate spontaneous interleukin-8 (IL-8) production in cultured SF mononuclear cells (SFMC) from RA. Furthermore, we examined whether IL-4, IL-10, or IL-1ra could influence the production of the arachidonic acid products leukotriene B4 (LTB4), 12-hydroxy-eicosatetraenoic acid (12-HETE) and 15-hydroxy-eicosatetraenoic acid (15-HETE). IL-4 induced a maximal suppression of 75% in the IL-8 secretion in SFMC from 10.0 ng/ml down to 2.5 ng/ml after 24 h and from 17.2 ng/ml to 4.2 ng/ml after 72 h of culture. IL-10 induced a 55% inhibition of the IL-8 secretion at 24 h and a 40% inhibition at 72 h. IL-1ra did not change the spontaneous IL-8 secretion from rheumatoid SFMC. We also examined, whether addition of IL-4, IL-10 or IL-1ra was able to modulate formation of the arachidonic acid products LTB4, 12-HETE and 15-HETE in cultured SF cells, stimulated with the calcium ionophore A23187. 15-HETE was not detected in untreated cultures, nor in IL-10 or IL-1ra treated cultures. IL-4, however, stimulated the formation of the anti-inflammatory mediator; 15-HETE (23 ng/10(6) cells). These results suggest that IL-4 or IL-10, could have beneficial anti-inflammatory effects in RA.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Arthritis, Rheumatoid; Humans; Hydroxyeicosatetraenoic Acids; Interleukin 1 Receptor Antagonist Protein; Interleukin-10; Interleukin-4; Interleukin-8; Leukotriene B4; Sialoglycoproteins; Synovial Fluid

To compare the cumulative effects of oral methotrexate (MTX) therapy (after 6-8 weeks) with the acute effects (24 hours after a dose) on arachidonic acid metabolism by the 5-lipoxygenase (5-LO) pathway in neutrophils from patients with active rheumatoid arthritis (RA) who were beginning therapy with MTX.. Neutrophils and monocytes were isolated from whole blood from 7 patients with RA, immediately before and 24 hours after their first weekly dose of 7.5 mg of MTX, and again after their dose at 6-8 weeks.. Total immunoreactive leukotriene B4 (LTB4) formation in neutrophils activated ex vivo with calcium ionophore A23187 was significantly suppressed (by 33%) before the 6-8-week dose, compared with the level before the first dose (mean +/- SEM 8.29 +/- 1.24 ng/10(6) cells at predose 6-8 weeks versus 12.29 +/- 2.13 ng/10(6) cells at predose 1; P = 0.03). Reductions were also observed after the first dose (27%; P = 0.07) and after the 6-8-week dose (43%; P = 0.05) compared with the respective predose levels. MTX treatment produced significant reductions in the total generation of 5-LO pathway products (5-hydroxyeicosatetraenoic acid + 6-trans-LTB4 + LTB4 + omega-oxidation products of LTB4) by calcium ionophore-activated neutrophils, as quantitated by integrated optical density after resolution on reverse-phase high-performance liquid chromatography. Decreases were observed after the first dose (26%; P = 0.025), immediately before the 6-8-week dose (23%; P = 0.05), and after the 6-8-week dose (47%; P = 0.0033) compared with levels before the first dose, and after the 6-8-week dose compared with the level before it (32%; P = 0.04). The generation of LTB4 by calcium ionophore-activated monocytes was not significantly affected by MTX therapy.. The significant decreases in the formation of omega-oxidation products of LTB4 and in the total generation of neutrophil 5-LO pathway products in the absence of a significant change in the release of 3H-arachidonic acid or the generation of platelet-activating factor suggest that the activity of the 5-LO enzyme in neutrophils is inhibited. We conclude that weekly oral MTX therapy in patients with active RA inhibits neutrophil 5-LO pathway product generation in a pattern consistent with inhibition of the activity of the 5-LO enzyme; an effect is observed after the first dose. The inhibition of 5-LO is cell-selective and cumulative, with a superimposed incremental inhibition observed after the weekly MTX dose.

Topics: Adult; Aged; Arachidonate 5-Lipoxygenase; Arthritis, Rheumatoid; Chemotaxis, Leukocyte; Humans; Leukotriene B4; Methotrexate; Middle Aged; Monocytes; Neutrophils; Time Factors

The inhibition of 5-lipoxygenase could be involved in the mechanism of action of methotrexate (MTX). We studied 8 patients with active rheumatoid arthritis (RA) immediately before and the day after the first dose of MTX (10 mg intramuscularly). Leukotriene B4 (LTB4) formation by polymorphonuclear leukocytes was significantly decreased (32%, p less than 0.01). This essentially involved released LTB4. A slight decrease was also obtained in omega-oxidation products. Similar results were obtained for plasma LTB4 (30%, p less than 0.02). A non-significant decrease in 5-HETE was noted. Conversely, 12-HETE was not modified. Our results suggest MTX has an effect on the 5-lipoxygenase pathway, particularly at the LTA4 epoxide hydrolase step, since 5-HETE and 6-trans-LTB4 isomers are not involved.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Arachidonate 12-Lipoxygenase; Arachidonate 5-Lipoxygenase; Arachidonic Acids; Arthritis, Rheumatoid; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Female; Humans; Hydroxyeicosatetraenoic Acids; Injections, Intramuscular; Leukotriene B4; Male; Methotrexate; Middle Aged; Neutrophils; Time Factors

Leukotriene B4 (LTB4) was measured in synovial fluid from 20 patients with rheumatoid arthritis and 15 patients with osteoarthritis. The level of LTB4 was significantly higher in synovial fluid from rheumatoid arthritis patients as compared with synovial fluid from osteoarthritis patients. LTB4 levels also significantly correlated with cell numbers, rheumatoid factor, and immune complexes in synovial fluid from rheumatoid arthritis patients. There was an inverse correlation between LTB4 levels and complement components. The high-pressure liquid chromatography peak of immunoreactivity extracted from the synovial fluid occurred at a retention volume identical to that of authentic LTB4. These results suggest that the increased level of this mediator in synovial fluid may contribute to perpetuation of inflammation and tissue destruction in rheumatoid arthritis.

Topics: Adult; Aged; Antigen-Antibody Complex; Arthritis, Rheumatoid; Complement System Proteins; Female; Humans; Leukotriene B4; Male; Middle Aged; Osteoarthritis; Synovial Fluid

The effects of sulfasalazine (SASP) and its metabolites sulfapyridine (SP) and 5-aminosalicylic acid (5-ASA) were investigated on release of prostaglandins (PG) and leukotrienes (LT) from synovial tissue of 37 patients with osteoarthritis, chondrocalcinosis and rheumatoid arthritis. Calcium ionophore A23187 significantly increased the release of PGE2, 6-keto-PGF1 alpha, LTB4, and LTC4 from human synovial tissue irrespective of the underlying joint disease. SASP inhibited release of LTC4 and increased release of PGE2. On the other hand, 5-ASA and SP inhibited the release of all eicosanoids measured. The effective concentrations of SASP and SP were found to be in the range which can be reached during SASP therapy. On the other hand, blood and synovial fluid levels of 5-ASA are considerably lower than those which inhibit eicosanoid synthesis in vitro. While nonsteroidal anti-inflammatory drugs, which are used for symptomatic therapy of rheumatoid arthritis, inhibit cyclooxygenase only, SP, the active metabolite of the second line anti-rheumatic drug SASP, inhibits both PG and LT release. Inhibition of LT synthesis by SASP and SP could contribute to the second line efficacy of SASP therapy in rheumatoid arthritis.

Topics: 6-Ketoprostaglandin F1 alpha; Aminosalicylic Acids; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Chondrocalcinosis; Culture Techniques; Dinoprostone; Humans; Knee Joint; Leukotriene B4; Leukotrienes; Mesalamine; Osteoarthritis; Prostaglandins; SRS-A; Sulfapyridine; Sulfasalazine; Synovial Membrane

We studied the effect of tenidap sodium, a new antiinflammatory/antirheumatic drug (120 mg/day for 7 days), on eicosanoid production and neutrophil degranulation in patients with rheumatoid arthritis. Endogenous prostaglandin E2 levels and ex vivo production of leukotriene B4 (LTB4) were measured in synovial fluid samples obtained at baseline and 1 week later. We measured peripheral blood polymorphonuclear cell (PMN) degranulation following surface-bound IgG stimulation, a possible 5-lipoxygenase product-mediated event, by determining lactoferrin and elastase release into the culture fluid. We found decreased levels of endogenous prostaglandin E2 as measured by radioimmunoassay, and decreased ex vivo production of LTB4 by PMN as measured by high performance liquid chromatography, in synovial fluid samples from patients who took tenidap. Release of the granule proteins lactoferrin and elastase was decreased in PMN obtained from patients receiving tenidap, as well as in the PMN incubated in vitro with tenidap. Improvement in clinical measures paralleled the biochemical changes. The unique 5-lipoxygenase inhibitory property of tenidap, as measured by LTB4 production and degranulation, suggests that it may have clinical activity which differentiates it from nonsteroidal antiinflammatory drugs.

Topics: Aged; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Cell Degranulation; Cells, Cultured; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Dinoprostone; Humans; Indoles; Lactoferrin; Leukotriene B4; Lipoxygenase Inhibitors; Middle Aged; Neutrophils; Oxindoles; Pancreatic Elastase; Radioimmunoassay; Synovial Fluid

Monocytes from peripheral blood and synovial fluid of patients with definite and classic rheumatoid arthritis spontaneously produced significantly greater amounts of prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and interleukin-1 beta (IL-1 beta) than samples of peripheral blood from normal controls. Peripheral blood monocytes from patients with rheumatoid arthritis produced significantly greater amounts of PGE2 than control samples when stimulated with lipopolysaccharide. There were no significant differences in the spontaneous release of superoxide or N-acetyl-beta-D-glucosaminidase by peripheral blood monocytes between patients and healthy controls. Both stimulated and unstimulated peripheral blood monocytes from patients with definite or classic rheumatoid arthritis produced significantly greater amounts of PGE2 than samples from normal controls. This was true, regardless of the stage of disease and the presence or absence of roentgenological joint abnormalities. Amounts of N-acetyl-beta-D-glucosaminidase released by peripheral blood monocytes from patients correlated positively with the erythrocyte sedimentation rate (ESR) and negatively with duration of disease. Amounts of IL-1 beta and N-acetyl-beta-D-glucosaminidase released from the peripheral blood monocytes of patients who had had their disease for less than one year were significantly higher than those of normal controls. There were no significant correlations between the types of treatment and the amounts of PGE2, LTB4, IL-1 beta or N-acetyl-beta-D-glucosaminidase released by peripheral blood monocytes in patients with rheumatoid arthritis. The findings suggest that monocytes are activated in patients with rheumatoid arthritis both at the onset of disease and during its chronic phase, and that they produce large amounts of mediators which may have a role in the induction and extension of the inflammatory process which leads to tissue damage.

Topics: Acetylglucosaminidase; Arthritis, Rheumatoid; Dinoprostone; Female; Humans; Interleukin-1; Leukotriene B4; Male; Middle Aged; Monocytes; Superoxides

We studied the effects of a single, oral dose of methotrexate (MTX) on arachidonic acid metabolism in neutrophils from 6 patients with rheumatoid arthritis, which were obtained 1 day before and 1 day after their usual weekly MTX dose. The 6 patients had received a mean weekly MTX dose of 9.6 mg (range 5-15) for a mean of 61.7 months (range 58-64), and none received concomitant corticosteroids. Total generation of leukotriene B4 (LTB4) in neutrophils stimulated ex vivo with 10 microM calcium ionophore A23187 for 20 minutes was significantly suppressed, by a mean of 53%, after the MTX dose compared with the predose levels (mean +/- SEM 13.0 +/- 1.4 ng/10(6) cells versus 6.0 +/- 0.9 ng/10(6) cells; P = 0.0019), reflecting a comparable suppression of both released and cell-retained LTB4. A 49% decrease in omega-oxidation products of LTB4 demonstrates that decreased LTB4 synthesis, rather than increased degradation, is responsible for the decrease in LTB4 generation. The absence of a significant change in either 3H-labeled arachidonic acid release or platelet-activating factor generation indicates that the observed decrease in LTB4 synthesis was apparently not caused by diminished phospholipase A2 activity. A 28% decrease in the total formation of the 5-lipoxygenase products 5-hydroxyeicosatetraenoic acid and the 6-trans-LTB4 diastereoisomers, and a 48% suppression of production of LTB4 plus its omega-oxidation metabolites after the MTX dose suggest inhibition of 5-lipoxygenase activity and possible suppression of leukotriene A4 epoxide hydrolase activity.

Topics: Aged; Arachidonic Acid; Arachidonic Acids; Arthritis, Rheumatoid; Calcimycin; Chemotaxis, Leukocyte; Humans; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Methotrexate; Middle Aged; Neutrophils; Phospholipases; Platelet Activating Factor

Circulating human neutrophil granulocytes (PMNs) from patients with rheumatoid arthritis (RA) have earlier been described to possess an enhanced capacity for production of certain 5-lipoxygenase-derived metabolites of arachidonic acid (AA), 5-hydroxyeicosatetraenoic acid (5-HETE) and leukotriene B4 (LTB4). In the present investigation the endogenous AA metabolism of synovial fluid PMNs of RA patients was studied and compared with that of the corresponding circulating PMNs. Synovial fluid PMNs prelabelled with 14C-AA released significantly less radioactivity than circulating PMNs when stimulated with calcium ionophore. Furthermore, synovial fluid PMNs produced significantly smaller amounts of both 5-HETE and LTB4 than circulating PMNs from the same patients, whereas no such difference was observed in the LTB4 catabolites or the cyclo-oxygenase products. More information dealing with the complex way in which arachidonic acid is metabolized in diseased RA joints may provide future rational approaches in the treatment of this chronic inflammatory disease.

Topics: Adult; Aged; Arachidonic Acids; Arthritis, Rheumatoid; Female; Humans; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Male; Middle Aged; Neutrophils; Synovial Fluid

The synthesis of products of the 5-lipoxygenase pathway by synovial fluid (SF) and peripheral blood neutrophils of 12 patients with rheumatoid arthritis was compared in 3 experimental conditions using high performance liquid chromatographic analysis. Major differences were observed when blood and SF neutrophils were incubated with ionophore A23187, the formation of all 5-lipoxygenase products being lower (p less than 0.0005) in the SF neutrophils. Addition of exogenous arachidonic acid to the A23187 stimulated cells partially overcame the difference in 5-lipoxygenase product synthesis between the 2 neutrophil populations. In contrast, upon incubation with arachidonic acid alone, SF neutrophils produced significantly larger amounts of 5-lipoxygenase products. The increased reactivity of the SF neutrophil 5-lipoxygenase to arachidonic acid and the decreased 5-lipoxygenase product synthesis upon A23187 stimulation may be the consequence of the previous activation of the cells and 5-lipoxygenase product synthesis in situ.

Topics: Adult; Aged; Arachidonic Acids; Arthritis, Rheumatoid; Cells, Cultured; Chromatography, High Pressure Liquid; Female; Humans; Lasalocid; Leukotriene A4; Leukotriene B4; Leukotrienes; Male; Middle Aged; Neutrophils; SRS-A; Synovial Fluid

Leukotriene B4 (LTB4) is an activator of white blood cells (WBC) and it has been suggested that its inhibition may be useful in rheumatoid arthritis (RA). Its production by peripheral WBC has not yet been investigated. We measured LTB4 production in 105 patients with RA and compared it with 59 matched controls. C-reactive protein (CRP) and ESR were measured in 90 patients and correlated with LTB4 values. Ten millilitres of blood were drawn. Separation was undertaken to obtain polymorphonuclear leukocytes (PMN) which were stimulated with calcium ionophore, and the supernatant was frozen for radioimmunoassay of LTB4. Results show that RA patients produce significantly higher levels of LTB4. It has been suggested that blockage of the cyclo-oxygenase enzyme by non-steroid anti-inflammatory drugs (NSAID) leads to increased production of LT via the lipoxygenase enzyme. Twenty-one patients not taking NSAID were compared with 84 on therapy. There was no significant difference. A linear regression was used to obtain Pearson's correlation coefficients. With LTB4 and CRP, r = 0.3 (p less than 0.003). With LTB4 and ESR, r = 0.25 (p less than 0.02). Low but significant correlations with CRP and ESR were obtained.

Topics: Adult; Aged; Arthritis, Rheumatoid; Blood Sedimentation; C-Reactive Protein; Humans; Leukotriene B4; Middle Aged; Neutrophils

Leukotriene B4 (LTB4) synthesis in rheumatoid synovitis was studied using peripheral and synovial fluid polymorphonuclear leukocytes (PMNs) and rheumatic synovial lining cells. No differences were found in LTB4 synthesis between peripheral PMNs from healthy volunteers and rheumatoid arthritis patients. When peripheral and synovial PMNs from the same RA patient were compared, arachidonic acid-induced LTB4 synthesis in synovial fluid PMNs was increased 1.7-7.2 fold, whereas the response to Ca ionophore A23187 stimulation was similar. This suggests 5-lipoxygenase stimulating factor(s) in inflamed joints. Rheumatic synovial lining cells in a primary cell culture produced small amounts of LTB4, the concentrations being less than 0.1 per cent of those of prostaglandin E2 (PGE2). PGE2 synthesis in synovial cells was increased when arachidonic acid or interleukin-1 was added to the culture, whereas LTB4 production remained unaltered. The present results suggest that in inflamed joints LTB4 originates mainly from PMNs whereas synovial lining cells are the source for PGE2.

Topics: Adult; Aged; Arthritis, Rheumatoid; Dinoprostone; Humans; Leukotriene B4; Leukotrienes; Middle Aged; Neutrophils; SRS-A; Synovial Fluid; Synovitis

This study investigated the presence of arachidonic acid metabolites, (leukotriene B4, leukotriene C4 and prostaglandin E2) in the serum, synovial fluid and synovium of rheumatoid arthritis patients (RA). We obtained the serum, synovial fluid and synovium from 16 female patients with RA during knee operations. Leukotriene B4 (LTB4), leukotriene C4 (LTC4) and prostaglandin E2 (PGE2) were detected by RIA analysis. In the patients administered steroids, a positive correlation was found between the concentrations of LTB4 and PGE2 in the synovium. In the patients not administered steroids, significant correlations were found between the concentrations of LTB4 in the synovium and serum, and also between the concentrations of LTB4 and LTC4 in the synovium. The levels of immunoglobulins and LTB4 in the serum were determined and a significant correlation was found between the content of IgG and the concentration of LTB4. In the serum, the concentration of LTB4 was elevated in RA patients relative to the control normal subjects, and the difference was statistically significant. In conclusion, these data suggest that LTB4 in the serum reflects the concentration of LTB4 in the synovium.

Topics: Arthritis, Rheumatoid; Dinoprostone; Female; Humans; Immunoglobulin G; Leukotriene B4; SRS-A; Synovial Fluid; Synovial Membrane

Fourteen patients with rheumatoid arthritis (RA) were studied before, during, and after a 1-week total fast. Disease activity decreased, as did the neutrophil release of lysozyme induced by the ionophore A23187. The ability of zymosan-activated RA patient serum to aggregate control neutrophils was reduced, together with serum concentrations of C3. The relative contents of arachidonic acid and eicosapentaenoic acid were increased in serum, platelets, and neutrophils, whereas levels of linoleic acid and linolenic acid were unchanged. Fasting also reduced the release of leukotriene B4 from neutrophils. We thus conclude that a reduced ability to generate cytotaxins, reduced release of enzyme, and reduced leukotriene formation from RA neutrophils, together with an altered fatty acid composition of membrane phospholipids, may be mechanisms for the decrease of inflammatory symptoms that results from fasting.

Topics: Adult; Aged; Arthritis, Rheumatoid; Fasting; Fatty Acids; Female; Humans; Leukotriene B4; Lipid Metabolism; Lipids; Middle Aged; Neutrophils

The formation of 5-lipoxygenase products (5-hydroxyeicosatetraenoic acid [5-HETE], leukotriene B4 [LTB4], and leukotriene C4 [LTC4]) by polymorphonuclear and mononuclear leukocytes isolated from peripheral blood of patients with rheumatoid arthritis was evaluated and compared with the data obtained from a group of control subjects. Although the levels of arachidonic acid metabolites via 5-lipoxygenase pathway by stimulated polymorphonuclear cells were comparable between patients and controls, mononuclear leukocytes from patients synthesized, when stimulated, significantly greater amounts of 5-HETE, LTB4, and LTC4 than did cells isolated from normal subjects. In addition, the release of superoxide anion, stimulated by either a particulate or a soluble stimulus, was increased in mononuclear cells from patients. The enhanced capacity of peripheral mononuclear leukocytes isolated from patients with rheumatoid arthritis to generate proinflammatory metabolites of arachidonic acid and oxygenated species with bactericidal and tissue-damaging properties may contribute to the pathogenesis of this complex disease.

Topics: Arthritis, Rheumatoid; Calcimycin; Cell Aggregation; Humans; Hydroxyeicosatetraenoic Acids; Leukocytes, Mononuclear; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Phagocytosis; SRS-A; Superoxides

Topics: Arthritis, Rheumatoid; Fish Oils; Humans; Leukotriene B4; Prostaglandins; Thromboxanes

A procedure for the quantification of leukotriene B4 (LTB4) in synovial fluid has been developed using gas chromatography/tandem mass spectrometry based on selected reaction monitoring of the elimination of t-butyldimethylsilanol from the ions of m/z 431 and 438 in the negative ion chemical ionization mass spectra of the di-t-butyldimethylsilyl/pentafluorobenzyl derivatives of leukotriene B4 and the internal standard (2H8)leukotriene B4. The detection limit (approximately 10 pg ml-1) is sufficiently low to permit determination of LTB4 concentration in the synovial fluid of patients with various arthropathies. Single-stage mass spectrometry was found not to be selective enough to permit quantification of LTB4 in synovial fluid.

Topics: Arthritis, Rheumatoid; Gas Chromatography-Mass Spectrometry; Humans; Leukotriene B4; Osteoarthritis; Synovial Fluid

The calcium dependent metabolism of endogenous arachidonic acid (AA) was investigated in 17 patients with rheumatoid arthritis during treatment with dextropropoxyphene alone and in 25 healthy volunteers. Incorporation of [1-14C]AA into intracellular phospholipids of purified neutrophils was achieved by incubation until steady state before activation with ionophore A23187. Analysis of extracellular metabolites was performed by extraction, thin layer chromatography, autoradiography, and laser densitometry. The patients showed a twofold increase in the total capacity for oxidation of AA. Release of leucotriene B4 (LTB4) and its omega oxidation products, 20-OH LTB4 and 20-COOH LTB4, was 29%, range 11-48%, in patients compared with 8%, range 4-12%, in healthy volunteers. Total amounts of radioactivity released and the specific activity of LTB4, as assessed by high pressure liquid chromatography, were equal in experimental and control groups. The demonstrated increased capacity for metabolism of AA to the major proinflammatory metabolite, LTB4, via the 5-lipoxygenase pathway may contribute to perpetuation of inflammation and to tissue destruction in rheumatoid arthritis.

Topics: Adult; Aged; Arachidonic Acid; Arachidonic Acids; Arthritis, Rheumatoid; Calcimycin; Chromatography, Thin Layer; Female; Humans; Leukotriene B4; Male; Middle Aged; Neutrophils

The object of this study was to investigate the importance of omega oxidation in regulating leukotriene B4 (LTB4) levels in man. In human polymorphonuclear leukocytes metabolism of LTB4 was rapid but was critically dependent on PMN number: greater than 1.5 X 10(6) PMN/ml were required. Metabolism of LTB4 was blocked in the presence of plasma. In whole blood and in PMN-rich rheumatoid synovial fluids no significant metabolism of LTB4 was detected within 30 min at 37 degrees C. We conclude that LTB4 metabolism at inflamed sites will be regulated both by cellular content and the degree of plasma exudation. In most pathological conditions rapid exchange with the micro-vasculature will be more important than metabolism in limiting LTB4 levels.

Topics: Arthritis, Rheumatoid; Cell Count; Humans; In Vitro Techniques; Kinetics; Leukotriene B4; Neutrophils; Oxidation-Reduction; Synovial Fluid

The metabolism in vitro of synthetic leukotriene B4 (LTB4) in synovial fluid from rheumatoid arthritis and osteoarthritis patients and in whole blood from these same patient groups and from normal volunteers has been studied. A linear relationship existed between a plot of the time of incubation of samples with LTB4 and the percentage of the initial concentration of LTB4 at each time point. The slope of this line, the rate constant for metabolism, has been used to compare different samples. LTB4 was metabolised more rapidly in the synovial fluid of rheumatoid arthritis patients than osteoarthritis patients. Furthermore, LTB4 was metabolised more rapidly in the blood of rheumatoid arthritis patients than either osteoarthritis patients or normal volunteers. These differences in metabolism correlate with the polymorphonuclear leukocyte (PMN) and albumin content of samples. It is suggested that binding of LTB4 to albumin in vivo will in part determine the available concentration of LTB4 in inflammatory lesions.

Topics: Arthritis, Rheumatoid; Humans; In Vitro Techniques; Kinetics; Leukotriene B4; Neutrophils; Osteoarthritis; Reference Values; Synovial Fluid

Topics: Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Cells, Cultured; Eicosanoic Acids; Humans; Hydrocortisone; Leukotriene B4; Neutrophils; Penicillamine; Prostaglandins; Synovial Fluid; Thromboxane B2

Despite the extensive use of sulfasalazine (SAS) and/or 5-aminosalicylic acid (5-ASA) in patients with inflammatory bowel disease and, more recently, rheumatoid arthritis, their mode of action has not been elucidated so far. None of the numerous pharmacological and biochemical effects described, including immunosuppressive, antifolate, and modulatory actions on lymphocyte and leukocyte functions, could be defined unequivocally as mediating their beneficial activity. Recently, interest has focused on actions of SAS and 5-ASA on the various enzymes of the arachidonic acid cascade. Mucosa of patients with inflammatory bowel disease generates excessive amounts of cyclooxygenase products such as prostaglandins (PG) as well as 5-lipoxygenase products such as leukotriene (LT) B4 and sulfidopeptide-LT. Both PG and LT exert proinflammatory actions and are potentially important mediators of mucosal inflammation. SAS and 5-ASA, however, have been found to inhibit PG synthesis under certain experimental conditions only, while increasing PG formation under other conditions. While SAS was found to inhibit colonic LTB4 synthesis, 5-ASA was reported to selectively affect the cyclooxygenase pathway of arachidonate metabolism in this tissue. Our results demonstrate that, like the parent compound, the metabolite 5-ASA in a dose-dependent manner inhibits release of LTB4 and sulfidopeptide-LT from normal human colonic mucosa (IC50 3.5 and 3.7 mmol/liter, respectively). Indomethacin, which has no efficacy in the treatment of patients with inflammatory bowel disease, on the other hand, selectively inhibited PGE2 formation in normal and inflamed colonic mucosa (IC50 1.7 and 1.0 mmol/liter, respectively) without reducing synthesis of LTB4 or sulfidopeptide-LT.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aminosalicylic Acids; Arachidonic Acid; Arachidonic Acids; Arthritis, Rheumatoid; Colitis, Ulcerative; Crohn Disease; Dose-Response Relationship, Drug; Humans; In Vitro Techniques; Intestinal Mucosa; Leukotriene B4; Leukotriene E4; Mesalamine; Rectum; SRS-A; Sulfasalazine

Six patients suffering from rheumatoid arthritis with massive knee joint effusions were treated with single daily doses of 600 mg pirazolac, a novel non-steroidal anti-inflammatory drug, for 3 days. Before the first dose, 3 hours after the second and the third dose, specimens of plasma and synovial fluid were drawn simultaneously. Plasma and synovial fluid concentrations of pirazolac, as determined by HPLC, amounted to 47.9 micrograms/ml and 19.8 micrograms/ml (Day 2) and 55.5 micrograms/ml and 18.7 micrograms/ml (Day 3), respectively. The samples were analyzed for PGE2, LTB4, LTC4 and LTD4 applying various extraction procedures and subsequent radioimmunoassays. PGE2 levels decreased during treatment from 928 pg/ml to 443 pg/ml after the third dose of pirazolac. LTB4 levels were slightly but insignificantly augmented. LTC4 and LTD4 concentrations were below the detection limit prior to and after administration of the drug.

Topics: Aged; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Rheumatoid; Dinoprostone; Fatty Acids, Unsaturated; Female; Humans; Leukotriene B4; Male; Middle Aged; Prostaglandins E; Pyrazoles; Synovial Fluid

Leukotriene B4 (LTB4), generated from arachidonic acid following lipoxygenase activity by a variety of inflammatory leucocytes, has been shown to be present in synovial fluid from patients with active rheumatoid arthritis. It does not persist as such, being converted to less active metabolites. The role of LTB4 as one of the natural mediators of inflammation is discussed.

Topics: Adult; Arthritis, Rheumatoid; Female; Humans; Leukocytes; Leukotriene B4; Male; Middle Aged; Neutrophils; Synovial Fluid

Topics: Anti-Inflammatory Agents; Arachidonic Acids; Arthritis, Rheumatoid; Humans; Inflammation; Leukotriene B4; Prostaglandins

Topics: Animals; Anti-Inflammatory Agents; Arthritis, Rheumatoid; Guinea Pigs; Humans; Leukotriene B4; Prostaglandins

Topics: Arachidonic Acids; Arthritis, Rheumatoid; Humans; Leukotriene B4; Synovial Fluid

The predominant lipoxygenase products of arachidonic acid were extracted and purified from synovial fluid and sonicates of synovial tissue of patients with rheumatoid arthritis (RA), spondyloarthritis (SA), or a noninflammatory arthropathy (NIA). The concentration of 5(S),12(R)-dihydroxy-6,8,10-(trans/trans/cis)-14-cis-eicosatetraenoic acid (leukotriene B4) in synovial fluid was elevated significantly in patients with RA and a positive latex test for rheumatoid factor (P < 0.05, n = 14) and in patients with SA (P < 0.05, n = 10), compared with that of subjects with NIA (n = 9). The content of 5(S)-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), but not of leukotriene B4, was elevated significantly in synovial tissue of seven patients with RA in comparison with that of four subjects with NIA (P < 0.05). A single intra-articular injection of corticosteroid significantly lowered the synovial fluid level of leukotriene B4 in six patients with RA. These data suggest an involvement of the potent chemotactic factors 5-HETE and leukotriene B4 in human inflammatory disease.

Topics: Arachidonic Acids; Arthritis, Rheumatoid; Chemotactic Factors; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Lipoxygenase; Neutrophils; Spondylitis, Ankylosing; Synovial Fluid