Inhibition of leukotriene B4 synthesis in neutrophils from patients with rheumatoid arthritis by a single oral dose of methotrexate

The Underling Mechanisms Exploration of Rubia cordifolia L. Extract Against Rheumatoid Arthritis by Integrating Network Pharmacology and Metabolomics

Purpose

Rubia cordifolia L. (RC) is a classic herbal medicine for the treatment of rheumatoid arthritis (RA) and has been used since ancient times. The ethanol extract of Rubia cordifolia L. (RCE) showed obvious anti-RA effects in our previous study. However, further potential mechanisms require more exploration. We aimed to investigate the mechanism of RCE for the treatment of RA by integrating metabolomics and network pharmacology in this study.

Methods

An adjuvant-induced arthritis (AIA) rat model was established, and we evaluated the therapeutic effects of RCE. Metabolomics of serum and urine was used to identify the differential metabolites. Network pharmacology was applied to determine the key metabolites and potential targets. Finally, the potential targets and compounds of RCE were verified by molecular docking.

Results

The results indicated that RCE suppressed foot swelling and alleviated joint damage and also had anti-inflammatory properties by inhibiting the expressions of tumor necrosis factor (TNF)-α, Interleukin (IL)-1β, prostaglandin E2 (PGE2), and P65. Ten and seven differential metabolites were found in the serum and urine, respectively, of rats. Six key targets, ie, phospholipase A2 group IIA (PLA2G2A), phospholipase A2 group X (PLA2G10), cytidine deaminase (CDA), uridine-cytidine kinase 2 (UCK2), charcot-leyden crystal galectin (CLC), and 5',3'-nucleotidase, mitochondrial (NT5M), were discovered by network pharmacology and metabolite analysis and were found to be related to glycerophospholipid metabolism and pyrimidine metabolism. Molecular docking confirmed that the favorable compounds showed affinities with the key targets, including alizarin, 6-hydroxyrubiadin, ruberythric acid, and munjistin.

Conclusion

This study revealed the underlying mechanisms of RCE and provided evidence that will allow researchers to further investigate the functions and components of RCE against RA.

Current and emerging pharmacotherapy for chronic spontaneous Urticaria: a focus on non-biological therapeutics

INTRODUCTION

Chronic spontaneous urticaria (CSU) refers to urticaria (wheals) or angioedema, which occur for a period of six weeks or longer without an apparent cause. The condition may impair the patient's quality of life.

AREAS COVERED

Treatment for CSU is mainly symptomatic. Both AAAAI/ACAAI practice parameters and EAACI/GA2LEN/EDF/WAO guidelines suggest CSU management in a stepwise manner. First-line therapy is with second-generation H₁-antihistamines. Treatment should be stepped up along the algorithm if symptoms are not adequately controlled. Increasing the dosage of second-generation H₁-antihistamines, with the addition of first-generation H₁-antihistamines, H₂ antagonist, omalizumab, ciclosporin A, or short-term corticosteroid may be necessary. New medications are being developed to treat refractory CSU. They include spleen tyrosine kinase inhibitor, Bruton tyrosine kinase inhibitor, prostaglandin D₂ receptor inhibitor, H₄-antihistamine, and other agents. The authors discuss these treatments and provide expert perspectives on the management of CSU.

EXPERT OPINION

Second-generation H₁-antihistamines remain the first-line therapeutic options for the management of CSU. For patients not responding to higher-dose H₁-antihistamines, international guidelines recommend the addition of omalizumab. Efficacy and safety data for newer agents are still pending. Large-scale, well-designed, randomized, double-blind, placebo-controlled trials will further provide evidence on the safety profile and efficacy of these agents in patients with CSU.

Chronic inflammatory diseases are stimulated by current lifestyle: how diet, stress levels and medication prevent our body from recovering

Serhan and colleagues introduced the term "Resoleomics" in 1996 as the process of inflammation resolution. The major discovery of Serhan's work is that onset to conclusion of an inflammation is a controlled process of the immune system (IS) and not simply the consequence of an extinguished or "exhausted" immune reaction. Resoleomics can be considered as the evolutionary mechanism of restoring homeostatic balances after injury, inflammation and infection. Under normal circumstances, Resoleomics should be able to conclude inflammatory responses. Considering the modern pandemic increase of chronic medical and psychiatric illnesses involving chronic inflammation, it has become apparent that Resoleomics is not fulfilling its potential resolving capacity. We suggest that recent drastic changes in lifestyle, including diet and psycho-emotional stress, are responsible for inflammation and for disturbances in Resoleomics. In addition, current interventions, like chronic use of anti-inflammatory medication, suppress Resoleomics. These new lifestyle factors, including the use of medication, should be considered health hazards, as they are capable of long-term or chronic activation of the central stress axes. The IS is designed to produce solutions for fast, intensive hazards, not to cope with long-term, chronic stimulation. The never-ending stress factors of recent lifestyle changes have pushed the IS and the central stress system into a constant state of activity, leading to chronically unresolved inflammation and increased vulnerability for chronic disease. Our hypothesis is that modern diet, increased psycho-emotional stress and chronic use of anti-inflammatory medication disrupt the natural process of inflammation resolution ie Resoleomics.

Effect of the leukotriene A4 hydrolase aminopeptidase augmentor 4-methoxydiphenylmethane in a pre-clinical model of pulmonary emphysema

The leukotriene A(4) hydrolase enzyme is a dual functioning enzyme with the following two catalytic activities: an epoxide hydrolase function that transforms the lipid metabolite leukotriene A(4) to leukotriene B(4) and an aminopeptidase function that hydrolyzes short peptides. To date, all drug discovery efforts have focused on the epoxide hydrolase activity of the enzyme, because of extensive biological characterization of the pro-inflammatory properties of its metabolite, leukotriene B(4). Herein, we have designed a small molecule, 4-methoxydiphenylmethane, as a pharmacological agent that is bioavailable and augments the aminopeptidase activity of the leukotriene A(4) hydrolase enzyme. Pre-clinical evaluation of our drug showed protection against intranasal elastase-induced pulmonary emphysema in murine models.

Low dosages: new chemotherapeutic weapons on the battlefield of immune-related disease

Chemotherapeutic drugs eliminate tumor cells at relatively high doses and are considered weapons against tumors in clinics and hospitals. However, despite their ability to induce cellular apoptosis, chemotherapeutic drugs should probably be regarded more as a class of cell regulators than cell killers, if the dosage used and the fact that their targets are involved in basic molecular events are considered. Unfortunately, the regulatory properties of chemotherapeutic drugs are usually hidden or masked by the massive cell death induced by high doses. Recent evidence has begun to suggest that low dosages of chemotherapeutic drugs might profoundly regulate various intracellular aspects of normal cells, especially immune cells. Here, we discuss the immune regulatory roles of three kinds of chemotherapeutic drugs under low-dose conditions and propose low dosages as potential new chemotherapeutic weapons on the battlefield of immune-related disease.

Methotrexate--how does it really work?

Methotrexate remains a cornerstone in the treatment of rheumatoid arthritis and other rheumatic diseases. Folate antagonism is known to contribute to the antiproliferative effects that are important in the action of methotrexate against malignant diseases, but concomitant administration of folic or folinic acid does not diminish the anti-inflammatory potential of this agent, which suggests that other mechanisms of action might be operative. Although no single mechanism is sufficient to account for all the anti-inflammatory activities of methotrexate, the release of adenosine from cells has been demonstrated both in vitro and in vivo. Methotrexate might also confer anti-inflammatory properties through the inhibition of polyamines. The biological effects on inflammation associated with adenosine release have provided insight into how methotrexate exerts its effects against inflammatory diseases and at the same time causes some of its well-known adverse effects. These activities contribute to the complex and multifaceted mechanisms that make methotrexate efficacious in the treatment of inflammatory disorders.

Therapeutic alternatives for chronic urticaria: an evidence-based review, Part 2

OBJECTIVE

To evaluate the use of alternative therapies for chronic urticaria refractory to first-line treatments in an evidence-based manner.

DATA SOURCES

MEDLINE searches were performed cross-referencing urticaria with the names of multiple therapies. Articles were then reviewed for additional citations. Articles published after 1950 were considered.

STUDY SELECTION

All articles, including case reports, were reviewed for soundness and relevance.

RESULTS

Experience has been reported for a wide variety of alternative therapies in the treatment of chronic idiopathic and physical urticarias. Evidence for most agents is limited to anecdotal reports. The therapies reviewed are also categorized based on criteria of safety, efficacy, convenience, and cost. The less preferred alternative agents in the second part of this review are divided between third-line therapies and others that are unable to be firmly recommended or that seem promising but lack substantial evidence.

CONCLUSIONS

Third-line alternative agents should be considered in patients with chronic urticaria who are severely affected and unresponsive to antihistamines and second-line therapies. Although monitoring for toxicity is important in management with third-line agents, safety remains favorable for most agents compared with corticosteroids.

Effects of perioperative antiinflammatory and immunomodulating therapy on surgical wound healing

Patients with various rheumatologic and inflammatory disease states commonly require drugs known to decrease the inflammatory or autoimmune response for adequate control of their condition. Such drugs include nonsteroidal antiinflammatory drugs (NSAIDs), cyclooxygenase (COX)-2 inhibitors, corticosteroids, disease-modifying antirheumatic drugs (DMARDs), and biologic response modifiers. These drugs affect inflammation and local immune responses, which are necessary for proper wound healing in the perioperative setting, thereby potentially resulting in undesirable postoperative complications. Such complications include wound dehiscence, infection, and impaired collagen synthesis. The end result is delayed healing of soft tissue and bone wounds. The current literature provides insight into the effect of some of these drugs on wound healing. For certain drugs, such as methotrexate, trials have been conducted in humans and direct us on what to do during the perioperative period. Whereas with other drugs, we must rely on either small-animal studies or extrapolation of data from human studies that did not specifically look at wound healing. Unfortunately, no clear consensus exists on the need and optimum time for withholding therapy before surgery. Likewise, clinicians are often uncertain of the appropriate time to resume therapy after the procedure. For those drugs with limited or no data in this setting, the use of pharmacokinetic properties and biologic effects of each drug should be considered individually. In some cases, discontinuation of therapy may be required up to 4 weeks before surgery because of the long half-lives of the drugs. In doing so, patients may experience an exacerbation or worsening of disease. Clinicians must carefully evaluate individual patient risk factors, disease severity, and the pharmacokinetics of available therapies when weighing the risks and benefits of discontinuing therapy in the perioperative setting.

Effect of methotrexate on Th1 and Th2 immune responses in mice

We investigated the effect of the anti-rheumatic drug methotrexate (MTX) on Th1 and Th2 immune responses in mice. For this investigation, mice were immunized subcutaneously at the base of the tail with ovalbumin (OVA) emulsified with complete Freund's adjuvant (day 0). Varying doses of MTX were orally administered daily from days 0 to 20. On day 21, anti-OVA IgG2a and interferon-gamma (IFN-gamma) as indicators of Th1 responses and anti-OVA IgG1 and interleukin-10 (IL-10) as those of Th2 responses were measured. The results showed that treatment with MTX was followed by decreases in OVA-specific IgG and proliferation of spleen cells to the antigen. The anti-rheumatic drug inhibited both anti-OVA IgG2a and IgG1 production, although the inhibitory effect of MTX on the antigen-specific IgG2a production appeared to be greater than that on IgG1 production. IFN-gamma, but not IL-10, secretion was markedly downregulated by MTX. Administration of MTX resulted in suppression of antigen (OVA)-induced arthritis in mice. The suppression of the joint inflammation by MTX was associated with inhibition of OVA-specific proliferative responses of spleen cells, anti-OVA IgG, IgG2a and IgG1 production, and IFN-gamma and IL-10 secretion, although more pronounced decreases in IgG2a and IFN-gamma were observed compared with those in IgG1 and IL-10 in MTX-treated mice. These results indicate that MTX appears to suppress Th1 and, to a lesser extent, Th2 immune responses and its anti-arthritic effect on human rheumatoid arthritis might be at least in part explained by down-regulation of Th1 responses involved in the disease.

[Takayasu's disease: interest in methotrexate treatment]

Takayasu's disease is a nonspecific aortic arteritis that affects mostly young women and sometimes children. Usual treatment consists of early and prolonged steroids. Some patients do not respond to this treatment, become steroid-dependent or suffer from side effects. We report a case in which methotrexate proved to be effective.

CASE REPORT

A 6-year-old girl presented with Takayasu's disease with elevated blood pressure of renovascular origin. Corticosteroids controlled the inflammatory syndrome but not the renal involvement and stopped the growth. Methotrexate (10 mg/m2/week) resulted in the control of the disease, the reduction of steroids and normal growth.

CONCLUSION

In Takayasu's disease, steroids should be given as first-line therapy. In case of failure, side effects or steroid dependency, small doses of methotrexate may facilitate the disease's control and weaning from the steroids.

Polyglutamation of antifolates is not required for induction of extracellular release of adenosine or expression of their anti-inflammatory effects

Methotrexate (MTX) exerts an anti-inflammatory effect, reportedly by enhancing the release of adenosine, through an accumulation of 5-amino-4-imidazolecarboxamide ribonucleotide (AICAR). To examine the role of polyglutamation in promoting anti-inflammatory effects by antifolates, we tested whether a new antifolate designed to be resistant to intracellular polyglutamation (MX-68) exhibited anti-inflammatory effects and stimulated adenosine release. Both MX-68 and MTX (at concentrations greater than 0.1 microM) increased the release of adenosine from Daudi cells in vitro. Inhibition of AICAR synthesis suppressed adenosine release by MX-68 and MTX. The anti-inflammatory effects of antifolates were estimated using the murine air pouch model, in which a BALB/c mouse was intraperitoneally injected with MX-68 or MTX once a week for 3 weeks. MX-68 (0.5 mg kg(-1) week(-1)), as well as MTX, inhibited infiltration of leukocytes into the air pouch. This inhibitory effect was suppressed in the presence of an adenosine A(2) receptor antagonist, 3,7-dimethyl-1-propargylxanthine (DMPX). These results suggest that MX-68, like MTX, exerts anti-inflammatory effects through the accumulation of AICAR and release of adenosine. These results suggest that polyglutamation of antifolate is not required for expression of anti-inflammatory effects.

Inhibition of neutrophil migration soon after initiation of treatment with leflunomide or methotrexate in patients with rheumatoid arthritis: findings in a prospective, randomized, double-blind clinical trial in fifteen patients

OBJECTIVE

Leflunomide is a novel immunomodulating drug that has recently been approved as a disease-modifying antirheumatic drug for the treatment of rheumatoid arthritis (RA). The aim of this study was to determine the relationship between the clinical effects of leflunomide and neutrophil migration.

METHODS

The effects of leflunomide and methotrexate on neutrophil chemotaxis were studied in 15 RA patients who participated in a prospective, randomized, double-blind clinical trial. When possible, neutrophil numbers were counted in synovial fluid (SF) samples at baseline and after 14 days, 4 months, and 1 year of treatment. The chemotactic properties of peripheral blood neutrophils from RA patients treated with either leflunomide or methotrexate were studied by the Boyden chamber technique, using the activators formyl-methionyl-leucyl-phenylalanine (fMLP) and interleukin-8 (IL-8). The in vitro effects of A77 1726, the active metabolite of leflunomide, and methotrexate on peripheral blood neutrophils from 7 healthy control subjects were also investigated.

RESULTS

Both therapy groups exhibited clinical improvement, including rapid reductions in SF neutrophil counts and reduced joint swelling and tenderness. On day 14, 3 of 7 patients who received leflunomide showed no detectable effusions. There was a significant effect on neutrophil chemotaxis (P < 0.001), which was similar for leflunomide and methotrexate. The direct effects on the neutrophils diminished over time. Incubation of peripheral blood neutrophils from healthy controls with A77 1726 confirmed the inhibitory effect on chemotaxis.

CONCLUSION

Leflunomide treatment is beneficial in RA patients. Different mechanisms are operative in various phases of treatment, leading to decreased recruitment of inflammatory cells in the joints.

Enhanced production of tissue inhibitor of metalloproteinases by peripheral blood mononuclear cells of rheumatoid arthritis patients responding to methotrexate treatment

OBJECTIVE

To determine the effects of methotrexate (MTX) treatment of rheumatoid arthritis (RA) patients (a) on the circulating levels and (b) on the ex vivo production of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinases-1 (TIMP-1) by peripheral blood mononuclear cells (PBMNC).

METHODS

Circulating levels, spontaneous ex vivo and in vitro production of MMP-1, TIMP-1 and interleukin-6 (IL-6) were assessed by immunoassays in sera and culture supernatants of PBMNC derived from 27 patients with active RA before and 3 months after beginning MTX treatment and from seven healthy subjects. The production and serum levels of MMP-1, TIMP-1 and IL-6 were correlated to the clinical response.

RESULTS

PBMNC of RA patients showing >/= 20% improvement of the Paulus index after 3 months of MTX treatment (responders; n = 16) exhibited a significantly enhanced production of spontaneous TIMP-1 ex vivo which was associated with the enhanced synthesis of IL-6. In contrast, PBMNC of 11 patients with <20% improvement and/or progression of disease showed a marked reduction of TIMP-1 and IL-6 secretion. Circulating levels of TIMP-1 remained unchanged in both groups whereas serum IL-6 levels declined in the responder group. MMP-1 was detectable only in very few culture supernatants and RA sera. Moreover, PBMNC of healthy donors revealed that MTX also stimulated TIMP-1 and IL-6 release in vitro, IL-6 being partially responsible for the induction of TIMP-1 production.

CONCLUSIONS

Both ex vivo and in vitro, the enhanced TIMP-1 production by PBMNC of RA patients and healthy individuals upon MTX treatment is associated with simultaneously enhanced IL-6 release, and enhanced ex vivo production of both is clearly associated with short-term clinical efficacy. This may reflect disease remission and favourable effects on host defence mechanisms against aberrant inflammation and extracellular matrix turnover in RA patients undergoing MTX treatment.

Tumour necrosis factor (TNF) production by T cell receptor-primed T lymphocytes is a target for low dose methotrexate in rheumatoid arthritis

Methotrexate (MTX) is an effective immunosuppressive agent in various chronic inflammatory diseases such as rheumatoid arthritis (RA). However, its mechanisms of action are only partially understood. In this study, we assessed the effects of MTX on the differentiation of peripheral blood (PB) CD4+CD45RA 'naive' and CD4+CD45RO 'memory' T cells from healthy controls and patients with RA. Accordingly, purified T cells were primed and restimulated in vitro via the T cell receptor (TCR) in the presence of IL-2 to generate effector T cells secreting large amounts of Th1 and Th2 cytokines. We observed that low doses of MTX strongly suppress TNF and to a lesser extent interferon-gamma (IFN-gamma) production by T cells from both healthy donors and RA patients when present during T cell priming via the TCR. Similar data were obtained for TCR-primed synovial fluid mononuclear cells in RA. In contrast, production of IL-4 by TCR-primed CD45RA T cells was significantly increased upon MTX treatment. Interestingly, MTX did not enhance IL-4 production when present during restimulation of effector CD45RO T cells, although it still suppressed TNF production. The results indicate that MTX effects depend on the stage of T cell activation and identify TNF production by TCR-primed T lymphocytes as a target for low-dose MTX treatment in RA. These findings could explain the delayed clinical effects of MTX and may contribute to its potent anti-inflammatory and immunoregulatory properties.

Induction of leukotriene production by bleomycin and asparaginase in mast cells in vitro and in patients in vivo

Bleomycin and asparaginase are widely used antineoplastic agents which may induce allergic or inflammatory side-effects. Mast cells are implicated as effector cells in allergic and inflammatory responses. The aim of this study was to establish whether bleomycin or asparaginase modulate leukotriene production in vitro and in vivo. Leukotriene C4 (LTC4) production by murine bone marrow-derived mast cells (BMMC) was determined by radioimmunoassay (RIA). Leukotriene production in patients was assessed by determining leukotriene E4 and N-acetyl-leukotriene E4 in urine by means of combined HPLC and RIA. Bleomycin induced an up to 2.1-fold increase in LTC4 production both in unstimulated and in calcium ionophore-stimulated mast cells. In 3 of 7 patients treated with bleomycin, a greater than 2-fold increase in endogenous leukotriene production was observed. This effect was associated with febrile responses and was most pronounced in a patient who developed an Adult Respiratory Distress Syndrome (ARDS). Asparaginase increased leukotriene production up to 10-fold in stimulated but not in unstimulated BMMC. In a patient who developed an anaphylactic reaction after treatment with asparaginase, a pronounced increase in urinary leukotriene concentration was observed. In contrast to bleomycin or asparaginase, a number of other cytostatic agents did not significantly change leukotriene production by BMMC. Our data indicate that some of the inflammatory and allergic side-effects of bleomycin and asparaginase could be mediated by leukotrienes, a possible source of which may be mast cells.

Antiinflammatory and immunoregulatory action of methotrexate in the treatment of rheumatoid arthritis: evidence of increased interleukin-4 and interleukin-10 gene expression demonstrated in vitro by competitive reverse transcriptase-polymerase chain reaction

OBJECTIVE

To look for in vitro modulation of the main immunoregulatory and antiinflammatory cytokines by methotrexate (MTX) during the course of rheumatoid arthritis (RA).

METHODS

We quantified interleukin-2 (IL-2), IL-4, IL-10, and interferon-gamma (IFNgamma) gene expression by peripheral blood mononuclear cells ex vivo under basal conditions and in vitro after stimulation with phytohemagglutinin (PHA) or PHA plus MTX, by competitive reverse transcriptase-polymerase chain reaction (RT-PCR), in 12 patients with untreated active RA (group 1), 10 patients with MTX-treated disease in partial remission (group 2), and 11 healthy control subjects. Simultaneously, under the same experimental conditions, we quantified cytokine production by specific enzyme-linked immunosorbent assays (ELISAs).

RESULTS

Under basal conditions, we found no differences in IL-2, IL-10, and IFNgamma gene expression in the 3 groups, while IL-4 gene expression was significantly decreased in RA patient group 1 compared with the control group. In vitro, under the action of MTX, IL-10 gene expression was significantly increased in the 3 groups, IL-4 gene expression was significantly increased in RA group 1 and in the control group, and IL-2 and IFNgamma gene expression was significantly decreased in RA group 1. Cytokine gene expression assessed by RT-PCR and cytokine production assessed by specific ELISAs were highly correlated.

CONCLUSION

In vitro modulation of the cytokine network by MTX, increasing Th2 cytokines and decreasing Th1 cytokines, could explain its antiinflammatory and immunoregulatory actions in vivo during the treatment of RA.

The mechanism of action of methotrexate

Because of methotrexate's well-documented efficacy in the treatment of rheumatoid arthritis, it is important that we understand the mechanism of action of this drug. There are two biochemical mechanisms by which methotrexate may modulate inflammation: (1) promotion of adenosine release and (2) inhibition of transmethylation reactions. Evidence is reviewed that favors the notion that the endogenous anti-inflammatory autocoid adenosine mediates the anti-inflammatory effects of methotrexate. This insight should aid in the design of new agents for the treatment of rheumatoid arthritis and other inflammatory diseases.

The mechanisms of action of disease-modifying antirheumatic drugs: a review with emphasis on macrophage signal transduction and the induction of proinflammatory cytokines

1. Rheumatoid arthritis (RA) is probably the most common source of treatable disability. A major problem in modern rheumatology is that the mechanism(s) of action of the currently used disease-modifying antirheumatic drugs (DMARDs) remain unclear. Many of these drugs entered rheumatology mainly through clinical intuition and have been used for decades. 2. The former T-cell-centered paradigm of rheumatoid inflammation has given way to a model of inflammation highlighting the macrophage and its proinflammatory cytokines. In particular, tumor necrosis factor alpha (TNF-alpha) has gained prominence as a central proinflammatory mediator in RA, and antibodies against TNF-alpha have been successfully used in patients with RA. 3. This review will summarize the recent advances in determining the mechanisms of action of the currently used DMARDs, with particular emphasis on their effects on the induction of TNF-alpha and interleukin 1 (IL-1) in mononuclear phagocytes. Although some DMARDs, such as auranofin, antimalarials and tenidap, act as inhibitors of the induction of these cytokines in monocytes or macrophages or both, other drugs, such as methotrexate, D-penicillamine and aurothiomalate, do not seem to affect either TNF-alpha or IL-1. 4. The drugs' effects on proinflammatory cytokine induction are correlated to those on other macrophage responses.

Inhibition of neutrophil-dependent cytotoxicity for human endothelial cells by antirheumatic drugs

Because polymorphonuclear (PMN) neutrophils are major effector cells in vasculitides, we assessed whether disease-modifying antirheumatic drugs impaired the ability of human PMNs to lyse human umbilical vein endothelial cells (HUVECs) in vitro. HUVECs were grown to confluence and labeled with chromium 51. PMNs, stimuli, and antirheumatic drugs were added stepwise, and the release of 51Cr was subsequently assessed. Lipoxin A4 (LXA4) and the oligopeptide fMLP, activating PMNs by surface receptors, conferred highly significant cytolysis that was dose-dependently reduced when auranofin, gold sodium aurothiomalate (GSTM), and sulfasalazine and its metabolites sulfapyridine and 5-ASA were added to the assay system. This protection remained, but with stimulus- and drug-specific variations, when either PMNs or HUVECs alone were treated with drugs before washings and PMN activation. In contrast, methotrexate did not protect HUVECs. Cytotoxicity conferred by the ionophore A23187 was inhibited by auranofin and GSTM only. Likewise, when HUVEC cytolysis was induced by two major cytotoxic mechanisms of PMNs, exogenous H2O2, or PMN lysates, auranofin and GSTM hampered lysis significantly. Thus in this in vitro model of vasculitis, auranofin, GSTM, sulfasalazine, sulfapyridine, and 5-ASA--but not methotrexate--dose-dependently reduced the PMN-dependent endothelial cell damage by effects on the PMNs as well as effects on the HUVECs.

Methotrexate inhibits superoxide production and chemotaxis in neutrophils activated by granulocyte colony-stimulating factor

Treatment of circulating human neutrophils with recombinant human granulocyte colony-stimulating factor (rhG-CSF) for 30 min augmented superoxide generation and chemotaxis induced by N-formylmethionyl-leucyl-phenylalanine (fMLP) in a dose dependent manner. When neutrophils were treated with 1 microM of methotrexate (MTX) for 60 min after incubation with rhG-CSF (10 ng/ml), the effects of rhG-CSF on superoxide generation and chemotaxis were inhibited by approximately 49 and 29%, respectively. Although inhibitory effects of MTX were also seen in neutrophils not pretreated with rhG-CSF, the degree of inhibition was much less. The addition of either hypoxanthine or guanosine at a concentration of 100 microM to the culture medium significantly attenuated the effects of MTX. However, in neutrophils obtained from a patient with Lesch-Nyhan syndrome, which lacked hypoxanthine-guanine phosphoribosyl transferase activity neither hypoxanthine nor guanosine had any rescue effect. These results suggest that MTX inhibits superoxide generation and chemotaxis in rhG-CSF-activated neutrophils, at least in part, by disturbing purine nucleotide biosynthesis.

Divergent effects of methotrexate on the clonal growth of T and B lymphocytes and synovial adherent cells from patients with rheumatoid arthritis

OBJECTIVE

To define the mechanisms whereby methotrexate (MTX) manifests its effects in patients with rheumatoid arthritis.

METHODS

T and B cells from peripheral blood and rheumatoid synovial tissues, synovial adherent cells, and the human fibrosarcoma cell line HT1080 and its mutant (defective in an enzyme in the nucleotide salvage pathway) were tested for clonal growth when cultured with MTX. Normal human fibroblasts and those with a deficiency in a salvage pathway were cultured with MTX in the presence or absence of purine and pyrimidine bases.

RESULTS

Clonal growth of T and B cells, but not synovial cells, was inhibited by clinically relevant concentrations of MTX. Slowly proliferating fibroblast lines were resistant to MTX, whereas their rapidly proliferating counterparts were not. However, mutant fibroblast lines deficient in a salvage pathway were sensitive to MTX despite slow proliferation. Similarly, while skin fibroblasts were resistant to MTX, germline mutant fibroblasts deficient in a salvage pathway were sensitive to small concentrations of MTX.

CONCLUSION

T and B lymphocytes, but not synovial cells, may be the target of MTX in vivo. Resistance to MTX may be associated with slow proliferation and the ability to synthesise nucleotides via salvage pathways. MTX can inhibit proliferation of even slowly growing cells by restricting the supply of nucleotides obtained via a salvage pathway, by removal of purine and pyrimidine bases, or by inducing a deficiency in a salvage pathway. It may be possible to manipulate the therapeutic effect of MTX by adjusting the amounts of purines and pyrimidines available to the cells in vivo.

Postoperative joint infections in rheumatoid arthritis patients on methotrexate therapy

The effect of low dose methotrexate (MTX) on postoperative complications in rheumatoid arthritis patients undergoing elective total joint arthroplasty was observed prospectively in 32 patients. Patients were assigned to discontinue MTX the week prior to and during the week of surgery (Group 1, n = 19) or to continue MTX throughout the perioperative period (Group 2, n = 13). Nineteen patients in Group 1 had 26 procedures, with no postoperative infections. Thirteen patients in Group 2 had 16 procedures, with 4 postoperative infections: 2 infected prostheses, 1 infected joint fusion, and 1 deep wound infection (P = .03). No patient had a postoperative flare of rheumatoid arthritis. Temporary discontinuation of MTX prior to joint arthroplasty appears to decrease the risk of postoperative infection.

Effects of methotrexate, sulphasalazine and aurothiomalate on polymorphonuclear leucocytes in rheumatoid arthritis

The aim of the study was to evaluate the effects of treatment with methotrexate, sulphasalazine and aurothiomalate on polymorphonuclear leucocytes (PMN) in rheumatoid arthritis (RA). Circulating PMNs from 58 RA patients treated with either methotrexate (n = 27), sulphasalazine (n = 16) or aurothiomalate (n = 15) were assayed for their chemotactic capacity and generation of superoxide anions. The expression of CD18/CD11b was measured for 17 RA patients treated with methotrexate. Chemotaxis and generation of superoxide anions were not affected by any of the three drugs. We found no difference in the expression of CD18/CD11b in RA patients treated with methotrexate compared to healthy subjects. Further methotrexate and aurothiomalate did not in vitro alter chemotaxis, generation of superoxide anion or expression of CD18/CD11b on normal PMNs. In conclusion we found no evidence that the effect of methotrexate, aurothiomalate or sulphasalazine in RA can be explained by modulation of chemotactic ability or superoxide anion generation of peripheral circulating PMNs.

Methotrexate for the treatment of severe mucocutaneous lupus erythematosus

We report three women with severe, chronic mucocutaneous lupus erythematosus who showed a significant improvement during oral methotrexate therapy; the improvement was sustained after the drug was discontinued. Their disease had previously been refractory to a wide range of conventional systemic immunosuppressive therapies. Other treatments were progressively withdrawn, and control was maintained, for a variable length of time, with methotrexate alone, or with a small dose of prednisolone.

Conversion of endogenous arachidonic acid to 5,15-diHETE and lipoxins by polymorphonuclear cells from patients with rheumatoid arthritis

The conversion of endogenous arachidonic acid (AA) by polymorphonuclear cells (PMN) from patients with rheumatoid arthritis (RA) was studied before (D0) and one day (D1) after antiinflammatory drug therapy. The biosynthesis of 5,15-diHETE and lipoxins (LXS), were investigated ex vivo, after PMN stimulation by ionophore A23187 without exogenous addition of 15-HETE. The eicosanoids were resolved by RP-HPLC and simultaneously detected at 246 and 302 nm respectively. Large amounts of 5,15-diHETE (50 to 400 ng/10(7) PMN) and significant levels of LXS (from 2 to 20 ng/10(7) PMN) were produced with individual differences between donors. Metabolite levels varied between patients but this work showed for the first time a linear relationship between the amounts of 5,15-diHETE and LXS. Moreover LXS production after treatment may be related to long-term clinical improvement of patients.

Plasma thiols, copper and rheumatoid arthritis

A means by which methotrexate diminishes the overproduction of leukotriene B4 by neutrophils from rheumatoid arthritic patients is described. It is postulated that neutrophil intracellular reduced glutathione is decreased by increased cellular copper, which results in leukotriene B4 overproduction. In the arthritic patient it is proposed that there is an inappropriate amount of a copper donor form of ceruloplasmin which contains a reduced copper that was formed during ceruloplasmin's oxidation of plasma cysteine. Oxidation of increased amounts of plasma homocysteine, present during methotrexate administration, restores ceruloplasmin's redox state leading to decreased copper transport into cells.

Should methotrexate be used to treat early rheumatoid arthritis?

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.

Methotrexate for steroid-resistant systemic lupus erythematosus

We here report two patients with steroid-resistant systemic lupus erythematosus (SLE) who were successfully treated with methotrexate (MTX). In both cases, a steroid resistant high fever, associated with mild myositis and pancytopenia were the main common findings, and all these symptoms were alleviated within a few days either by 7.5 mg or 5 mg MTX per week. The number of CD4+ cells increased along with the clinical improvement, whereas the number of CD20+ cells and HLA-DR expressing cells also decreased. Taking into account the side effects of high dose corticosteroids and cyclophosphamides, treatment with a weekly low dose of MTX is known to contribute to an improvement in the long-term prognosis for patients with refractory SLE.

Treatment of glucocorticoid-resistant or relapsing Takayasu arteritis with methotrexate

OBJECTIVE

To identify the role of methotrexate (MTX) in the treatment of persistent or recurrent Takayasu arteritis that is refractory to treatment with glucocorticoids (GC) alone.

METHODS

An open-label pilot study of weekly low-dose MTX+GC treatment was performed. Outcome was evaluated according to clinical characteristics, laboratory abnormalities, findings on routinely performed angiographic studies, and ability to withdraw GC and MTX therapy. Eighteen patients entered the study; 2 dropped out, and 16 were followed up for a mean period of 2.8 years (range 1.3-4.8 years).

RESULTS

Weekly administration of MTX (mean stable dose of 17.1 mg) and GC resulted in remissions in 13 of 16 patients (81%). However, 7 patients (44%) had relapses as GC was tapered to or near discontinuation. Retreatment again led to remission, and 3 of 7 patients in this group have successfully stopped GC therapy. Of those patients who achieved remission, 8 (50%) have sustained remissions of 4-34 months (mean 18 months), and 4 of this group have not required GC or MTX therapy for 7-18 months (mean 11.3 months). Three patients experienced disease progression in spite of treatment.

CONCLUSION

About half of all Takayasu arteritis patients have chronic active disease for which GC therapy alone does not provide sustained remissions that allow withdrawal of treatment. Weekly low-dose MTX is an effective means of inducing remission and minimizing GC therapy and toxicity in most of these patients. Further long-term studies will be required to assess the durability of remission and the need for maintenance MTX therapy in this subset of Takayasu arteritis patients.

Methotrexate in rheumatoid arthritis. An update

Methotrexate has been approved for the treatment of refractory rheumatoid arthritis by several regulatory agencies, including the Food and Drug Administration. The tendency is now to prescribe it at earlier stages of the disease. Methotrexate is a well known antifolate. Its exact mechanism of action in rheumatoid arthritis remains uncertain. The polyglutamated derivatives of methotrexate are potent inhibitors of various enzymes, including dihydrofolate reductase and 5-aminoimidazole-4-carboxamide ribonucleotide transformylase. Inhibitory effects on cytokines, particularly interleukin-1, and on arachidonic acid metabolism, as well as effects on proteolytic enzymes, have been reported. Some of them may be linked to the antifolate properties of methotrexate. Overall, the drug appears to act in rheumatoid arthritis as an anti-inflammatory agent with subtle immunomodulating properties. Direct inhibitory effects on rapidly proliferating cells in the synovium have also been suggested. Methotrexate is usually given orally. Marked interindividual variation in its bioavailability has been found. Food intake has no significant effect on the pharmacokinetics of oral methotrexate. Methotrexate undergoes significant metabolism. The functionally important metabolites are the polyglutamated derivatives of methotrexate, which are selectively retained in the cells. Less than 10% of a dose of methotrexate is oxidised to 7-hydroxy-methotrexate, irrespective of the route of administration. This metabolite is extensively (91 to 93%) bound to plasma proteins, in contrast to the parent drug (35 to 50% bound). Methotrexate is mainly excreted by the kidneys. It undergoes tubular secretion and may thereby compete with various organic acid compounds. Early placebo-controlled trials demonstrated that weekly low dosage methotrexate produced early symptomatic improvement in most rheumatoid arthritis patients. Two meta-analyses showed that methotrexate is among the most efficacious of slow-acting antirheumatic agents, together with parenteral gold (sodium aurothiomalate), penicillamine and sulfasalazine. Furthermore, in the short term context of clinical trials, methotrexate has one of the best efficacy/toxicity ratios. There is little evidence that methotrexate, or any available slow-acting antirheumatic agent, is a true disease-modifying drug. However, the probability that a patient will continue methotrexate therapy over time appears quite favourable compared with any other slow-acting antirheumatic drug. Combination therapy with slow-acting drugs has been advised for the management of rheumatoid arthritis, but the evidence currently available does not support general use of combination therapy including methotrexate. Almost all investigations indicated that toxic effects, rather than lack of response, were the major reason for discontinuing methotrexate therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

The antiinflammatory mechanism of methotrexate. Increased adenosine release at inflamed sites diminishes leukocyte accumulation in an in vivo model of inflammation

Methotrexate, a folate antagonist, is a potent antiinflammatory agent when used weekly in low concentrations. We examined the hypothesis that the antiphlogistic effects of methotrexate result from its capacity to promote intracellular accumulation of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) that, under conditions of cell injury, increases local adenosine release. We now present the first evidence to establish this mechanism of action in an in vivo model of inflammation, the murine air pouch model. Mice were injected intraperitoneally with either methotrexate or saline for 3-4 wk during induction of air pouches. Pharmacologically relevant doses of methotrexate increased splenocyte AICAR content, raised adenosine concentrations in exudates from carrageenan-inflamed air pouches, and markedly inhibited leukocyte accumulation in inflamed air pouches. The methotrexate-mediated reduction in leukocyte accumulation was partially reversed by injection of adenosine deaminase (ADA) into the air pouch, completely reversed by a specific adenosine A2 receptor antagonist, 3,7-dimethyl-1-propargylxanthine (DMPX), but not affected by an adenosine A1 receptor antagonist, 8-cyclopentyl-dipropylxanthine. Neither ADA nor DMPX affected leukocyte accumulation in the inflamed pouches of animals treated with either saline or the potent antiinflammatory steroid dexamethasone. These results indicate that methotrexate is a nonsteroidal antiinflammatory agent, the antiphlogistic action of which is due to increased adenosine release at inflamed sites.

The effect of methotrexate on lipoxygenase metabolism in neutrophils from rats: in vitro and ex vivo studies

Studies were undertaken to examine the effect of methotrexate (MTX) administered in vivo or added in vitro upon the production of the 5-lipoxygenase (5-LO) metabolites of arachidonic acid (AA) by rat neutrophils. Peptone-induced peritoneal exudate cells were stimulated by A23187 and the cell suspensions assayed for leukotriene B4 (LTB4), the all-trans isomers of LTB4 and 5-hydroxyeicosatetraenoic acid (5-HETE) using high-pressure liquid chromatography. MTX added in vitro to rat cells was weakly inhibitory; however, no inhibition of LTB4 production was seen following in vivo administration of MTX by oral, subcutaneous or intraperitoneal routes. On the basis of these findings, inhibition of 5-LO metabolism does not appear to explain the anti-inflammatory effects of MTX.

Reduction of leukocyte and interleukin-1 beta concentrations in the synovial fluid of rheumatoid arthritis patients treated with methotrexate

OBJECTIVE

To examine the effect of methotrexate (MTX) on the numbers of leukocytes in the peripheral blood (PB) and synovial fluid (SF) of patients with active rheumatoid arthritis (RA).

METHODS

Twelve patients were treated with MTX; 5 patients not taking MTX served as controls. Samples of PB and SF were collected at 0, 1, 4, and 8 weeks of the study. Disease activity was scored, and total leukocytes, neutrophils, lymphocytes, and CD4+, CD8+, DR+, and CD25+ lymphocyte subsets were analyzed in PB and SF. Interleukin-1 beta (IL-1 beta) concentrations in SF were determined.

RESULTS

Patients treated with MTX showed significant clinical improvement. No change in PB leukocytes or lymphocyte subsets was observed in either patient group over the 8-week study period. In contrast, the number of leukocytes, the number and proportion of neutrophils, and the concentration of IL-1 beta in the SF of patients treated with MTX were reduced. In addition, in MTX-treated patients, there was an appreciable decrease in SF CD8+ lymphocytes, but not CD4+, DR+, or CD25+ lymphocytes.

CONCLUSION

These findings suggest that in RA, MTX acts, at least in part, by reducing the migration of leukocytes into the inflamed synovium. Local reduction of IL-1 beta secretion may contribute to this effect.

The treatment of Wegener's granulomatosis with glucocorticoids and methotrexate

OBJECTIVE

To identify alternatives to daily low-dose cyclophosphamide (CYC) in the treatment of Wegener's granulomatosis (WG).

METHODS

An open-label pilot study of weekly low-dose methotrexate (MTX) plus glucocorticoids (GC) for treatment of patients with WG was performed. Twenty-nine patients who did not have immediately life-threatening disease were included. Outcome was determined by clinical characteristics, pathologic findings, course of illness, laboratory and radiographic findings, and successful withdrawal of GC therapy.

RESULTS

Weekly administration of MTX (at a mean stable dosage of 20 mg) and GC resulted in marked improvement in 76% of the 29 patients. Remission was achieved in 69% of the patients, 7% improved but had intermittent smoldering disease that precluded total withdrawal of GC, and 17% had progressive disease within 2-6 months of starting the study treatment. Two patients who initially achieved remission later had relapses after GC was discontinued. Of those who remain in remission (mean followup time 14.5 months), 72% have not required GC for a mean period of 10 months.

CONCLUSION

Although standard therapy for WG (daily CYC and GC) has dramatically improved outcome in this often-fatal disease, treatment morbidity has led to attempts to identify effective interventions that have less toxicity. Weekly low-dose MTX was shown in this study to be a feasible alternative to CYC in patients whose illness was not immediately life-threatening or in whom prior CYC treatment was ineffective or produced serious toxicity. Although these results are preliminary, they are encouraging and justify further studies in which MTX, CYC, and other alternative therapeutic approaches are compared concurrently.

The role of cytokines and their inhibitors in arthritis

The role of cytokines in inflammatory joint diseases is well documented, especially with regard to tissue destruction and remodelling. In these processes, IL-1 and TNF alpha play a prominent part by stimulating protease production. The regulation of their production, their release and their effects on target cells (e.g. synovial cells, chondrocytes and bone-derived cells) has therefore been the subject of intensive investigations. In this context a new dimension has emerged recently due to the observation of the existence of natural specific cytokine inhibitors. IL-1-ra and the soluble fragments of both TNF receptors--inhibitory by binding to TNF alpha--are natural products. These appear to be the molecules best suited for controlling the imbalance between pro- and anti-inflammatory processes. The use of the recombinant forms of these inhibitors may open new perspectives for therapeutic intervention. The fact that the respective mechanisms of action of receptor antagonists and inhibitory binding proteins differ does not rule out their complementarity. Preliminary experiments with animal models have yielded promising results which should be followed up by clinical trials.

Controlled trial of methotrexate versus 10-deazaaminopterin in the treatment of rheumatoid arthritis

A 15 week double blind controlled trial of methotrexate and 10-deazaaminopterin for the treatment of rheumatoid arthritis (RA) was performed in 26 patients. Significant improvement in all measured clinical parameters was observed in the two patient groups. The drugs were well tolerated; only one patient (10-deazaaminopterin) withdrew from the study because of side effects. It is concluded that, in the context of this relatively short clinical trial, 10-deazaaminopterin is at least as beneficial as methotrexate in the treatment of RA.

Acute and chronic suppression of leukotriene B4 synthesis ex vivo in neutrophils from patients with rheumatoid arthritis beginning treatment with methotrexate

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.