The effects of methotrexate on the production and activity of interleukin-1

Systemic bee venom exerts anti-arthritic and anti-inflammatory properties in a rat model of arthritis

Bee venom (BV) is widely used as a traditional China medicine to treat various conditions, including rheumatoid arthritis (RA). The aim of the present study was to evaluate the effects of systemic BV (60 mg/kg) as an anti-arthritic natural product, compare it with Methotrexate and determine the possible underlying mechanisms of BV action using complete Freund's adjuvant-induced arthritic rats. The development of signs of RA signs (knee joint circumference and arthritis scoring index) was evaluated. Erythrocyte sedimentation rate, serum tumor necrosis factor-α (TNF-α) and serum interleukin-1β (IL-1β) levels were measured at the end of the study. Histopathological examination followed by immunostaining of NF-κB (P65) was performed on the affected knee joints. Additionally, in vitro cyclooxygenase (COX) inhibition activity, carrageenan paw edema test and acetic acid writhing tests were performed to evaluate the anti-inflammatory and analgesic effects of the assessed dose and compared with diclofenac. An acute toxicity test was performed to establish the safety of BV at high doses. The results of the present study highlighted the potential of systemic BV on preventing the development of signs of RA. BV also significantly reduced serum levels of TNF-α, IL-1β and NF-κB in the affected joints. In addition to its potent analgesic activity, BV exhibited favorable inhibitory activity of the COX pathway in both in vivo and in vitro models. Therefore, high dose administration of systemic BV displayed safe and promising anti-arthritic, anti-inflammatory and analgesic properties through regulation of different mechanisms associated with the pathogenesis of RA.

Methotrexate an Old Drug with New Tricks

Methotrexate (MTX) is the first line drug for the treatment of a number of rheumatic and non-rheumatic disorders. It is currently used as an anchor disease, modifying anti-rheumatic drug in the treatment of rheumatoid arthritis (RA). Despite the development of numerous new targeted therapies, MTX remains the backbone of RA therapy due to its potent efficacy and tolerability. There has been also a growing interest in the use of MTX in the treatment of chronic viral mediated arthritis. Many viruses—including old world alphaviruses, Parvovirus B19, hepatitis B/C virus, and human immunodeficiency virus—have been associated with arthritogenic diseases and reminiscent of RA. MTX may provide benefits although with the potential risk of attenuating patients’ immune surveillance capacities. In this review, we describe the emerging mechanisms of action of MTX as an anti-inflammatory drug and complementing its well-established immunomodulatory activity. The mechanisms involve adenosine signaling modulation, alteration of cytokine networks, generation of reactive oxygen species and HMGB1 alarmin suppression. We also provide a comprehensive understanding of the mechanisms of MTX toxic effects. Lastly, we discussed the efficacy, as well as the safety, of MTX used in the management of viral-related rheumatic syndromes.

How I treat patients with adult onset Still's disease in clinical practice

Adult onset Still's disease (AOSD) is a rare systemic inflammatory disease of unknown etiology characterized by four cardinal signs which are almost always present in patients: high spiking fever, arthralgia (with or without synovitis), maculo-papular salmon-pink evanescent skin rash, striking leukocytosis with neutrophilia. Here, we review the clinical features of AOSD and describe the best practice approaches for its management, reviewing available guidelines and recommendations and providing experts' insights.

Effects of polysaccharide fractions isolated from Caltha palustris L. on the activity of phagocytic cells & humoral immune response in mice with collagen-induced arthritis: A comparison with methotrexate

BACKGROUND & OBJECTIVES

The extracts from Caltha palustris L. have been shown to be beneficial for treating arthritis and rheumatism. In this study, the immunomodulatory effects of polysaccharide fractions B and C of C. palustris extracts were studied, using the collagen-induced arthritis (CIA) mouse arthritis experimental model. The aim was to determine the activity of blood phagocytic cells and humoral immune response in CIA mice treated with polysaccharide fractions from C. palustris.

METHODS

The effects of fractions B and C of C. palustris were explored by evaluating phagocytic activity of peripheral blood granulocytes and monocytes and humoral immune response in sheep red blood cell (SRBC)-immunized mice. The results were compared with methotrexate (MTX) treatment. Following the onset of CIA, DBA/1J mice were treated for 21 days with B or C fractions (10 mg/kg; i.p.) or MTX (every 48 h, 6.6 mg/kg; i.p.).

RESULTS

The results showed that fraction B reduced the level of interleukin (IL)-1β, boosted nitric oxide synthesis in murine peritoneal macrophages stimulated in vitro with lipopolysaccharide and enhanced the monocyte phagocytic activity. Exposure of SRBC-immunized mice to fraction B and MTX during the course of CIA resulted in decreased total anti-SRBC haemagglutinin titres.

INTERPRETATION & CONCLUSIONS

Fraction B of C. palustris polysaccharides modulated macrophage function and exerted beneficial effects on the clinical course of CIA in mice. The results also suggested efficacy of fraction B was comparable to that of MTX treatment for certain parameters.

Transient low-dose methotrexate generates B regulatory cells that mediate antigen-specific tolerance to alglucosidase alfa

Biologic drugs, including enzyme-replacement therapies, can elicit anti-drug Abs (ADA) that may interfere with drug efficacy and impact patient safety. In an effort to control ADA, we focused on identifying regimens of immune tolerance induction that may be readily available for clinical use. Data generated in both wild-type mice and a Pompe disease mouse model demonstrate that single-cycle, low-dose methotrexate can be as effective as three cycles of methotrexate in providing a long-lived reduction in alglucosidase alfa-specific ADA. In addition, we show that methotrexate induces Ag-specific tolerance as mice generate similar Ab responses to an irrelevant Ag regardless of prior methotrexate treatment. Methotrexate-induced immune tolerance does not seem to involve cell depletion, but rather a specific expansion of IL-10- and TGF-β-secreting B cells that express Foxp3, suggesting an induction of regulatory B cells. The mechanism of immune tolerance induction appears to be IL-10 dependent, as methotrexate does not induce immune tolerance in IL-10 knockout mice. Splenic B cells from animals that have been tolerized to alglucosidase alfa with methotrexate can transfer tolerance to naive hosts. We hypothesize that methotrexate induction treatment concomitant with initial exposure to the biotherapeutic can induce Ag-specific immune tolerance in mice through a mechanism that appears to involve the induction of regulatory B cells.

Methotrexate induces production of IL-1 and IL-6 in the monocytic cell line U937

Introduction

Methotrexate (MTX) has been for decades a standard treatment in a wide range of conditions, from malignancies to rheumatoid arthritis (RA). Despite this long experience, the mechanisms of action of MTX remain incompletely understood. Reported immunologic effects of MTX include induction of increased production of some cytokines, an effect that seems to be at odds with the generally anti-inflammatory effects of this drug in diseases like RA. To further elucidate these immune activities, we examined effects of MTX on the human monocytic cell line U937.

Methods

The U937 cell line was treated in vitro with pharmacologic-range concentrations of MTX and effects on production of interleukin (IL)-1, IL-6 and TNF alpha were measured. Changes in gene expression for IL-1 and IL-6 and specificities in the Jun-N-terminal kinase (JNK) signaling pathway including JNK 1, JNK2, JUN and FOS were also determined. The contribution of NF-kB, folate and adenosine pathways to the observed effects was determined by adding appropriate inhibitors to the MTX cultures.

Results

MTX mediated a dose-dependent increase in IL-1 and IL-6 in U937 cells, as measured by secreted proteins and levels of gene expression. The increased cytokine expression was inhibited by addition of parthenolide and folinic acid, but not by caffeine and theophylline, suggesting that NF-kB and folates, but not adenosine, were involved in mediating the observed effects. When U937 cells were cultured with MTX, upregulated expression of JUN and FOS, but not JNK 1 or 2, also was observed.

Conclusions

MTX induces expression of proinflammatory cytokines in U937 monocytic cells. These effects might mediate the known toxicities of MTX including pneumonitis, mucositis and decreased bone mineral density.

Interactions among Low Dose of Methotrexate and Drugs Used in the Treatment of Rheumatoid Arthritis

Methotrexate (MTX) is a nonbiological disease-modifying antirheumatic drug that has shown both a good control of clinical disease and a good safety. Usually drug-drug interactions (DDIs) represent the most limiting factor during the clinical management of any disease, in particular when several drugs are coadministered to treat the same disease. In this paper, we report the interactions among MTX and the other drugs commonly used in the management of rheumatoid arthritis. Using Medline, PubMed, Embase, Cochrane libraries, and Reference lists, we searched for the articles published until June 30, 2012, and we reported the most common DDIs between MTX and antirheumatic drugs. In particular, clinically relevant DDIs have been described during the treatment with MTX and NSAIDs, for example, diclofenac, indomethacin, or COX-2 inhibitors, and between MTX and prednisone or immunosuppressant drugs (e.g., leflunomide and cyclosporine). Finally, an increase in the risk of infections has been recorded during the combination treatment with MTX plus antitumor necrosis factor-α agents. In conclusion, during the treatment with MTX, DDIs play an important role in both the development of ADRs and therapeutic failure.

Phase II trial of methotrexate in myasthenia gravis

Prednisone is a frequently used treatment for myasthenia gravis (MG) but it has numerous side effects. Methotrexate is a selective inhibitor of dihydrofolate reductase and lymphocyte proliferation and is an effective immuosuppressive medication for autoimmune diseases. Given the negative results of the mycophenolate mofetil study, search for an effective immunosuppressant drug therapy is ongoing. The objective is to determine if oral methotrexate is safe and effective for MG patients who take prednisone. We have initiated a randomized, double-blind, placebo-controlled multicenter trial of methotrexate versus placebo in patients taking at least 10 mg/day of prednisone at enrollment. The methotrexate dose is increased to 20 mg and the prednisone dose is adjusted per protocol during the study. Clinical and laboratory evaluations are performed monthly for 12 months, with the primary efficacy measure being the nine-month prednisone area under the curve (AUC) from months 3 to 12. Secondary outcome measures include MG outcomes, quality of life measures, and a polyglutamation biomarker assay. A total of 18 U.S. sites and 2 Canadian sites are participating, with 48 screened cases, 42 enrolled, with 19 still active in the study.

Identification of a cytokine network sustaining neutrophil and Th17 activation in untreated early rheumatoid arthritis

Introduction

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by sustained synovitis. Recently, several studies have proposed neutrophils and Th17 cells as key players in the onset and perpetuation of this disease. The main goal of this work was to determine whether cytokines driving neutrophil and Th17 activation are dysregulated in very early rheumatoid arthritis patients with less than 6 weeks of disease duration and before treatment (VERA).

Methods

Cytokines related to neutrophil and Th17 activation were quantified in the serum of VERA and established RA patients and compared with other very early arthritis (VEA) and healthy controls. Synovial fluid (SF) from RA and osteoarthritis (OA) patients was also analyzed.

Results

VERA patients had increased serum levels of cytokines promoting Th17 polarization (IL-1β and IL-6), as well as IL-8 and Th17-derived cytokines (IL-17A and IL-22) known to induce neutrophil-mediated inflammation. In established RA this pattern is more evident within the SF. Early treatment with methotrexate or corticosteroids led to clinical improvement but without an impact on the cytokine pattern.

Conclusions

VERA patients already display increased levels of cytokines related with Th17 polarization and neutrophil recruitment and activation, a dysregulation also found in SF of established RA. 0 Thus, our data suggest that a cytokine-milieu favoring Th17 and neutrophil activity is an early event in RA pathogenesis.

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.

TNF-alpha and neuropathic pain--a review

Tumor necrosis factor alpha (TNF-α) was discovered more than a century ago, and its known roles have extended from within the immune system to include a neuro-inflammatory domain in the nervous system. Neuropathic pain is a recognized type of pathological pain where nociceptive responses persist beyond the resolution of damage to the nerve or its surrounding tissue. Very often, neuropathic pain is disproportionately enhanced in intensity (hyperalgesia) or altered in modality (hyperpathia or allodynia) in relation to the stimuli. At time of this writing, there is as yet no common consensus about the etiology of neuropathic pain - possible mechanisms can be categorized into peripheral sensitization and central sensitization of the nervous system in response to the nociceptive stimuli. Animal models of neuropathic pain based on various types of nerve injuries (peripheral versus spinal nerve, ligation versus chronic constrictive injury) have persistently implicated a pivotal role for TNF-α at both peripheral and central levels of sensitization. Despite a lack of success in clinical trials of anti-TNF-α therapy in alleviating the sciatic type of neuropathic pain, the intricate link of TNF-α with other neuro-inflammatory signaling systems (e.g., chemokines and p38 MAPK) has indeed inspired a systems approach perspective for future drug development in treating neuropathic pain.

Steroid-resistant adult-onset Still's disease which showed a quick response to methotrexate

A case of steroid-resistant adult-onset Still's disease is herein reported. The patient consulted us because of night fever, arthralgia and evanescent rashes. She was diagnosed with adult-onset Still's disease, with a C-reactive protein (CRP) value of 29.5 mg/dL and serum ferritin level of 4500 ng/mL. The fever, rashes and arthralgia disappeared after medication of medium-dose oral prednisolone, however, the CRP value persisted at high levels, and the serum ferritin level nevertheless increased by 5200 ng/mL. Following the pulse therapy with corticosteroid, the CRP value decreased once but thereafter returned to a high level again. The serum ferritin level did not respond during that therapy. Finally, 10 days after starting the administration of methotrexate, the CRP value dramatically decreased from 7 mg/dL to 0.16 mg/dL, and thereafter the serum ferritin level started to decline, which thus enabled us to eventually taper the dose of oral prednisolone.

Immune tolerance induction to enzyme-replacement therapy by co-administration of short-term, low-dose methotrexate in a murine Pompe disease model

Clinical investigations of recombinant human acid alpha-glucosidase for the treatment of Pompe disease often reveal the appearance of therapy-specific antibodies. These antibodies could potentially interfere with recombinant human acid alpha-glucosidase efficacy and induce immunological consequences. Several immunosuppressive agents, including methotrexate, mycophenolate mofetil and cyclosporin A with azathioprine, were evaluated for their potential to induce immune tolerance to recombinant human acid alpha-glucosidase. Methotrexate was the only agent that reduced recombinant human acid alpha-glucosidase-specific antibody responses in acid alpha-glucosidase knock-out mice. A 3-week, low-dose methotrexate regimen controlled recombinant human acid alpha-glucosidase-specific antibody levels throughout 8 months of weekly recombinant human acid alpha-glucosidase treatment. The success of this methotrexate regimen appears to require methotrexate administration within the first 24 h of recombinant human acid alpha-glucosidase treatment. In an attempt to understand the benefit of methotrexate within the first day of recombinant human acid alpha-glucosidase administration, the immune response 24 h following intravenous recombinant human acid alpha-glucosidase treatment was investigated. A consistent expansion of peritoneal B1 B cells was observed. Control over this B1 B cell response may be part of the complex mechanism of action of methotrexate-induced immune tolerance.

Methotrexate enhances prostaglandin D2-stimulated heat shock protein 27 induction in osteoblasts

As for the pathogenesis of rheumatoid arthritis (RA), prostaglandins (PGs) act as important mediators of inflammation and joint destruction. Among them, PGD2 is well recognized as a potent regulator of osteoblastic functions. We previously showed that PGD2 stimulates the induction of heat shock protein 27 (HSP27) via protein kinase C (PKC)-dependent p38 mitogen-activated protein (MAP) kinase and p44/p42 MAP kinase in osteoblast-like MC3T3-E1 cells. Therefore, it is a current topic to clarify how HSP27 plays a role for regulating osteoblastic functions in the lesion of RA. On the other hand, methotrexate (MTX) is one of the most effective medicines for the treatment of RA. Here, we examined the effect of MTX on PGD2-stimulated HSP27 induction in MC3T3-E1 cells. The cells were pretreated with various doses of MTX including therapeutic dosage for RA, and then stimulated by PGD2. MTX significantly enhanced the PGD2- increased levels of HSP27 in a dose-dependent manner, although MTX alone had no effect on the levels of HSP27. In addition, MTX amplified the PGD2-increased levels of HSP27 mRNA. On the contrary, MTX had little effect on PGD2-induced formation of inositol phosphates, PKC activation and phosphorylations of MAP kinases. Our results strongly suggest that MTX enhances PGD2-stimulated HSP27 induction at a point downstream from MAP kinases in osteoblasts.

Reduction of synovial sublining layer inflammation and proinflammatory cytokine expression in psoriatic arthritis treated with methotrexate

OBJECTIVE

Methotrexate is one of the most commonly used disease-modifying antirheumatic drugs in the management of psoriatic arthritis (PsA). Despite the differences between the inflammation in PsA and rheumatoid arthritis (RA), the effects of methotrexate on the synovium have been described solely in RA. In this study, we sought to determine the effects of methotrexate on the inflammatory infiltrate and on cytokine and metalloproteinase gene expression in the synovium of PsA patients.

METHODS

Ten patients with PsA (median duration 18 months) underwent arthroscopy and synovial biopsy of an inflamed knee before and after clinical improvement induced by methotrexate. Immunohistologic analysis was performed using antibodies to CD3, CD4, CD8, CD68, factor VIII, vascular cell adhesion molecule, E-selectin, and intercellular adhesion molecule (ICAM). Matrix metalloproteinase 3 (MMP-3) and tissue inhibitor of metalloproteinases 1 (TIMP-1) messenger RNA (mRNA) were quantified by competitive reverse transcription-polymerase chain reaction (RT-PCR). Interleukin-1alpha (IL-1alpha), IL-1beta, IL-2, IL-4, IL-5, IL-8, IL-10, IL-12p35, IL-12p40, IL-15, interferon-gamma (IFNgamma), and tumor necrosis factor alpha (TNFalpha) mRNA expression was quantified by real-time PCR.

RESULTS

Patients received a median methotrexate dosage of 13.75 mg/week (range 7.5-15) for a median of 11.5 months (range 7-14 months). The Ritchie Articular Index, swollen joint count, and Disease Activity Score were significantly reduced. There was a decrease in all immunohistologic staining, although this was statistically significant only for CD3, CD4, CD8, CD68, E-selectin, and ICAM. Despite clinical improvement in all patients, there was a residual T cell infiltrate in all synovial biopsy tissues. The synovial lining layer thickness, but not hypervascularity, was significantly reduced. There was also a significant reduction in MMP-3, but not TIMP-1, expression. Before treatment, PsA synovium was characterized by a predominant expression of the proinflammatory cytokines IL-15, IFNgamma, IL-1beta, and TNFalpha and the antiinflammatory cytokine IL-10. Methotrexate reduced synovial IL-1alpha, IL-1beta, IL-8, IL-10, IL-15, IFNgamma, and TNFalpha mRNA expression, but the effect was significant only for IL-8.

CONCLUSION

Methotrexate produced a clinical response in PsA by reducing, but not abolishing, the inflammatory infiltrate, adhesion molecule expression, and MMP-3 and proinflammatory cytokine gene expression, particularly IL-8, in the synovium. Methotrexate did not reduce hypervascularity, which is a prominent differentiating feature of PsA synovium.

Methotrexate ameliorates T cell dependent autoimmune arthritis and encephalomyelitis but not antibody induced or fibroblast induced arthritis

OBJECTIVE

To investigate the mode of action of methotrexate (MTX) in different types of models for rheumatoid arthritis (RA) and multiple sclerosis (MS).

METHODS

Models for RA and MS were selected known to have different pathogenesis--that is, fibroblast induced arthritis in SCID mice, collagen induced arthritis (CIA), anticollagen II antibody induced arthritis (CAIA), and experimental autoimmune encephalomyelitis (EAE) in (Balb/c x B10.Q)F1 and B10.Q mice, and Pristane induced arthritis in DA rats (PIA). The MTX treatment was started 1 day after the onset of disease and continued for 14 days to compare effects on the different models.

RESULTS

All models known to be critically dependent on T cell activation (CIA, PIA, and EAE) were effectively down regulated by titrated doses of MTX. In contrast, no effects were seen on fibroblast induced arthritis or CAIA. No effects were seen on the levels of anticollagen II antibodies in the CIA experiment.

CONCLUSION

The data show that MTX has strong ameliorative effect on both classical models of RA, like CIA and PIA, but also on a model for MS, EAE. It also suggests that MTX operates only in diseases which are preceded by, and dependent on, T cell activation. A comparison of CAIA and CIA suggested that MTX operates independently of arthritogenic antibodies. These results demonstrate that different animal models reflect the complexity of the corresponding human diseases and suggest that several models should be used for effective screening of new therapeutic agents.

Methotrexate for immunosuppression in life-supporting pig-to-cynomolgus monkey renal xenotransplantation

Methotrexate (MTX) has been used successfully as an immunosuppressant in rodent xenotransplantation models, but the data generated so far with MTX in pig-to-baboon cardiac transplantation studies have been disappointing. The potential of this agent was consequently explored in a life-supporting pig-to-primate renal model using the cynomolgus monkey as the recipient species. Introductory in vitro and in vivo pharmacokinetic and pharmacodynamic studies with MTX were conducted in three cynomolgus monkeys. Subsequently, 10 cynomolgus monkey recipients of a life-supporting kidney from human decay-accelerating factor transgenic pigs were administered MTX intravenously according to three different regimens. All the animals also received cyclosporine A and steroids. In addition, mycophenolate sodium (MPS) was administered post-operatively in two of the three groups of transplanted animals. At clinically relevant concentrations, MTX is able in vitro to inhibit the mixed lymphocyte reactions (MLR) in cynomolgus monkeys. After intravenous administration, moreover, exposure of cynomolgus monkeys to MTX appeared to be higher than had been previously reported in baboons. Graft function was observed in the transplanted animals, which survived from 0 to 41 days. All but two animals revealed acute humoral rejection in the explanted graft and developed diarrhea. Diarrhea was the cause of euthanasia in five cases. It was unrelated to the administration of MPS and associated with severe histopathological signs of enteritis. This study demonstrates that the pharmacokinetic and pharmacodynamic profiles if MTX vary substantially between non-human primate species. In vitro, MTX has immunosuppressive properties in the cynomolgus monkey at clinically relevant concentrations. In vivo, MTX has a very narrow therapeutic window in cynomolgus monkeys, however, as it does in baboons. We conclude that MTX is scarcely effective as an immunosuppressant, be it for induction or maintenance, in pig-to-cynomolgus monkey renal xenotransplantation.

Decrease of B-cells and autoantibodies after low-dose methotrexate

The purpose was to assess the efficacy of low-dose methotrexate (MTX) on immunological parameters in patients with lupus erythematosus (LE) under short- (</=10 weeks) vs. long-term (>10 weeks) conditions. Patients who did not respond to classical LE treatment (antimalarials and/or glucocorticosteroids) were retrospectively analyzed. Twenty-two LE-patients received 10-30 mg MTX per week. Sera and ethylenediaminetetra-acetic blood specimens were analyzed for autoantibodies and lymphocyte subsets (flow cytometry), respectively. Clinical improvement occurred in 21 patients (complete response n = 15, 68.2%). B-cells were the main targets: their absolute number significantly dropped down after long-term treatment (290 +/- 49 vs. 221 +/- 41 microl(-1), P = 0.00254). This was accompanied by down-regulation of autoantibodies. The effect on B-cells was more pronounced in patients with (before vs. long-term 172 +/- 34 vs. 99 +/- 15 microl(-1), P = 0.02853) than without autoantibodies (169 +/- 40 vs. 144 +/- 51 microl(-1), P = 0.55406). MTX did not induce immunosuppression. Low-dose MTX has different short- and long-term effects on immunologic parameters, which could explain the clinical improvement.

Methotrexate inhibits proliferation and regulation of the expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 by cultured human umbilical vein endothelial cells

BACKGROUND

The mechanism by which a low dose of methotrexate (MTX) works to treat psoriasis is not clear. The overexpression of cell adhesion molecules on dermal vessels is important in the pathogenesis of psoriasis and is probably induced by upregulation of tumour necrosis factor (TNF)-alpha.

OBJECTIVES

To determine the effects of MTX at concentrations comparable with in vivo levels after the administration of low-dose MTX to human umbilical vein endothelial cells (HUVEC) on the growth and expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1).

METHODS

Cell proliferation assay, immunostaining, immunoblotting, cell enzyme-linked immunosorbent assay and reverse transcriptase-polymerase chain reaction (RT-PCR) were performed to examine the effects of MTX on HUVEC.

RESULTS

MTX inhibited the proliferation of HUVEC at 10-7 mol L-1 and 10-6 mol L-1 without showing cytotoxic effects. It also inhibited TNF-alpha-induced ICAM-1 and VCAM-1 expression by HUVEC at 10-6 mol L-1. The inhibitory effect of MTX was more pronounced on ICAM-1 expression than on VCAM-1 expression. RT-PCR analysis revealed that TNF-alpha-induced ICAM-1 gene expression was strongly downregulated by MTX.

CONCLUSIONS

Low-dose MTX may act on psoriasis by suppressing the TNF-alpha-induced expression of ICAM-1 and VCAM-1 by vascular endothelial cells. Inhibition of neovascularization may be another mechanism of action of MTX.

The induction of apoptosis by methotrexate in activated lymphocytes as indicated by fluorescence hyperpolarization: a possible model for predicting methotrexate therapy for rheumatoid arthritis patients

The objectives of this study were to test the in vitro response of healthy non-activated, activated, and rheumatoid arthritis (RA) lymphocytes to methotrexate (MTX), and design an in vitro model for predicting the efficiency of MTX treatment for RA patients. Considering the RA profile of clonal-expanded CD4(+) T cells, phytohemagglutinin-activated mononuclear cells taken from healthy donors were incubated with different concentrations of MTX. The MTX-immunosuppressive effect was tested by fluorescence intensity measurements, including PI assay and annexin V assay. For simple detection, we used the Individual Cell Scanner (IC-S), which enables the measurement of early events in individual cells. Healthy mononuclear cells (MNC), and MNC derived from RA patients, were tested by the IC-S while utilizing fluorescence polarization (FP) measurements of fluorescein diacetate (FDA) as an established marker of activation or suppression. In healthy activated MNC, we found that MTX, through its early incubation period, interferes with the activation signal obtained by PHA and exerts an apoptotic signal, which is noted by increases in the FP. Comparing our model to six long-standing RA patients and five newly-diagnosed patients revealed significant differences in the FP measurements, including fluorescence depolarization as an early established measurement of lymphocyte activation, and hyperpolarization as a measurement of an early immunosuppressive effect. We conclude that MTX, an effective therapy for RA patients, could easily be tested by fluorescence polarization measurements of FDA before (or during) clinical use in order to predict its efficiency on a specific RA patient. Moreover, the FP measurements can be used for the diagnosis, and making timing and dosage decisions.

FACS monitoring of lymphocyte-subsets in patients with discoid and subacute-cutaneous lupus erythematosus receiving low-dose methotrexate

OBJECTIVE

Our purpose was to describe and characterize the influence of low-dose methotrexate (MTX) treatment on absolute counts of peripheral blood cells and lymphocyte subsets in patients with cutaneous lupus erythematosus (LE).

METHODS

In 6 patients with discoid (DLE) and 9 patients with subacute-cutaneous LE (SCLE) who received low-dose MTX (10-30 mg/week) leukocytes and lymphocyte subsets were monitored flowcytometrically.

RESULTS

Absolute numbers of leukocytes, monocytes, lymphocytes, and lymphocyte subsets displayed cell-type specific patterns under low-dose MTX. Moreover, we found different reaction patterns in patients with DLE and SCLE. In patients with DLE leukocytes, lymphocytes, monocytes (p < 0.02), CD3+ cells (p < 0.04), CD3+ CD4+ cells (p < 0.009), and CD3+ CD8+ cells increase, and only B-cells decrease. Whereas in patients with SCLE no significant changes were found.

CONCLUSION

Low-dose MTX treatment seems to independently influence peripheral blood cell compartments and thereby the underlying LE manifestation could be of some relevance.

Immunomodulating drugs in the management of psoriatic arthritis

Psoriatic arthritis is a chronic inflammatory arthropathy which can be distinguished from rheumatoid arthritis on the basis of differing patient demographics, genetic predisposition, histopathologic change, radiographic appearance, and clinical course. The cause of psoriatic arthritis remains unknown but appears to be autoimmune in nature as its pathogenesis is characterized by persistent synovial inflammation resulting in damage to the articular cartilage and osteolysis. Compared with rheumatoid arthritis, distinct lymphocyte subpopulations and pro-inflammatory cytokine levels appear to be present within the joint but the importance and therapeutic implications of these differences is uncertain. The clinical presentation of psoriatic arthritis is variable and overlapping patterns of joint involvement affecting both the appendicular and axial skeleton are seen. For patients with mild synovial disease and a favorable prognosis, the use of a nonsteroidal anti-inflammatory drug for symptomatic relief is often sufficient. However, the destructive potential of psoriatic arthritis is increasingly recognized and patients with more synovial disease and radiographic change at presentation appear to be at risk for greater morbidity and increased mortality. Immunomodulating therapy has the potential to suppress joint inflammation and preserve functional capacity but true disease modification has yet to be shown. The toxicity associated with presently available immunomodulatory agents makes careful patient selection and conscientious monitoring essential. The efficacy of methotrexate and sulfasalazine in patients with psoriatic arthritis is well defined while more anecdotal reports of benefit exist for other agents including the antimalarials, azathioprine, colchicine, cyclosporine, and the retinoids. For all treatment regimens, the magnitude of clinical improvement demonstrated to date has been rather small and quite subjective in character with few controlled studies of adequate size and duration having been reported. Emerging biologic therapies, such as those which target tumor necrosis factor, will hopefully provide future treatment options with greater efficacy and improved safety for patients with psoriatic arthritis.

Methotrexate treatment for refractory subacute cutaneous lupus erythematosus

Methotrexate is beneficial in rheumatoid arthritis and has been used in small studies of patients with systemic lupus erythematosus. We describe a patient with severe subacute cutaneous lupus erythematosus refractory to therapy with antimalarials and corticosteroids. Treatment with methotrexate resulted in complete clearing of the skin lesions without any side effects.

Treatment of experimental adjuvant arthritis with the combination of methotrexate and lyophilized Enterococcus faecium enriched with organic selenium

The efficacy of combination therapy with methotrexate (MTX) and probiotic bacteria Enterococcus faecium enriched with organic selenium (EFSe) in rats with adjuvant arthritis was determined. Rats with adjuvant arthritis were given MTX (0.3 mg/kg 2-times weekly, orally); lyophilized E. faecium enriched with Se (15 mg/kg, 5 d per week, orally); and a combination of MTX plus EFSe for a period of 50 d from the immunization. Levels of serum albumin, serum nitrite/nitrate concentrations, changes in hind paw swelling, arthrogram score, bone erosions, whole body bone mineral density (BMD) and bone mineral content (BMC) were assayed in the rats as variables of inflammation and destructive arthritis-associated changes. Treatment with MTX and with the combination MTX + EFSe significantly inhibited markers of both inflammation and arthritis. Significant differences in favor of combination therapy with MTX + EFSe as compared to MTX alone were seen in serum albumin concentration, hind paw swelling and arthrogram score. Reductions in radiographic scores were also more pronounced in the combination therapy group. Combination therapy, but not MTX alone, inhibited the reduction of BMD and BMC; treatment with lyophilized EFSe alone had no significant effect on adjuvant arthritis in rats. The potent therapeutic effect of low dosage MTX therapy in combination with lyophilized EFSe on adjuvant arthritis in rats was shown.

Molecular action of methotrexate in inflammatory diseases

Despite the recent introduction of biological response modifiers and potent new small-molecule antirheumatic drugs, the efficacy of methotrexate is nearly unsurpassed in the treatment of inflammatory arthritis. Although methotrexate was first introduced as an antiproliferative agent that inhibits the synthesis of purines and pyrimidines for the therapy of malignancies, it is now clear that many of the anti-inflammatory effects of methotrexate are mediated by adenosine. This nucleoside, acting at one or more of its receptors, is a potent endogenous anti-inflammatory mediator. In confirmation of this mechanism of action, recent studies in both animals and patients suggest that adenosine-receptor antagonists, among which is caffeine, reverse or prevent the anti-inflammatory effects of methotrexate.

Establishment of a consistent L929 bioassay system for TNF-alpha quantitation to evaluate the effect of lipopolysaccharide, phytomitogens and cytodifferentiation agents on cytotoxicity of TNF-alpha secreted by adherent human mononuclear cells

TUMOR necrosis factor-alpha (TNF-alpha) plays an important role in the pathogenesis of rheumatoid arthritis. The present study was to evaluate the effects of lipopolysaccharide (LPS), phytomitogens and cytodifferentiation agents on cytotoxicity of TNF-alpha secreted by adherent human mononuclear cells (AMC). TNF-alpha cytotoxicity in LPS-treated, phytomitogen-treated, and cytodifferentiation agent-treated AMC supernatants were analyzed by the L929 bioassay system. Our results showed that LPS could induce homogeneous TNF-alpha production by AMC whereas, in addition to TNF-alpha, phytomitogens could also induce other TNF-like factors. Neither methotrexate, retinoic acid nor sodium butyrate can inhibit TNF-alpha cytotoxicity, while hexamethylene bisacetamide could not only inhibit TNF-alpha cytotoxicity but also TNF-alpha inducing ability of LPS to AMC.

[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.

Methotrexate therapy for chronic noninfectious uveitis: analysis of a case series of 160 patients

PURPOSE

To evaluate the outcomes of patients with chronic noninfectious uveitis unresponsive to conventional antiinflammatory therapy who were treated with methotrexate.

DESIGN

Retrospective noncomparative interventional case series.

PARTICIPANTS

All patients with chronic noninfectious uveitis treated with methotrexate at a single institution from 1985 to 1999.

METHODS

Charts of patients seen on the Ocular Immunology & Uveitis Service at the Massachusetts Eye & Ear Infirmary were reviewed. Patients with chronic uveitis of noninfectious origin treated with methotrexate were included in the study.

MAIN OUTCOME MEASURES

Control of inflammation, steroid-sparing effect, visual acuity, adverse reactions.

RESULTS

A total of 160 patients met the inclusion criteria. Control of inflammation was achieved in 76.2% of patients. Steroid-sparing effect was achieved in 56% of patients. Visual acuity was maintained or improved in 90% of patients. Side effects requiring discontinuation of medication occurred in 18% of patients. Potentially serious adverse reactions occurred in only 8.1% of patients. There was neither long-term morbidity nor mortality caused by methotrexate.

CONCLUSIONS

Methotrexate is effective in the treatment of chronic noninfectious uveitis that fails to respond to conventional steroid treatment. It is an effective steroid-sparing immunomodulator, is a safe medication, and is well tolerated.

FK506 potently inhibits T cell activation induced TNF-alpha and IL-1beta production in vitro by human peripheral blood mononuclear cells

The aim of this study was to elucidate the in vitro inhibitory potency of FK506 on production of the inflammatory cytokines, tumour necrosis factor (TNF)-alpha and interleukin (IL)-1beta, with a view to assessing this immunosuppressive agent as a potential anti-rheumatic drug. We employed an in vitro model which produces TNF-alpha and IL-1beta through T cell activation. Human peripheral blood mononuclear cells (PBMC) were cultured with immobilized anti-CD3/CD28 monoclonal antibody in this model. FK506 inhibited anti-CD3/CD28 induced TNF-alpha and IL-1beta production at concentrations less than 1 ng ml(-1). Flow cytometric analysis of intracellular TNF-alpha and IL-1beta positive cells showed that FK506 potently suppresses inflammatory cytokine production from CD14+ monocytes as well as from T cells. Cyclosporin A (CsA) and dexamethasone (DEX) also inhibited the anti-CD3/CD28 induced cytokine production, but were less potent than FK506. FK506 and CsA, but not DEX, specifically inhibited anti-CD3/CD28 induced inflammatory cytokine production without affecting the lipopolysaccaride (LPS) induced effect. Methotrexate (MTX) was completely inactive for suppressing cytokine production under either condition. Anti-CD3/CD28 stimulated PBMC culture supernatants were found to enhance the expression of adhesion molecules in human vascular endothelial cells. FK506, CsA and DEX led to the suppression of adhesion molecule expression probably by inhibiting cytokine production from PBMC. The inhibitory potency of agents on TNF-alpha and IL-1beta production was compared with cytotoxicity and FK506 was not cytotoxic at concentrations several orders of magnitude greater than those required for cytokine inhibition. These results strongly suggest that FK506 may be most effective to specifically prevent T cell activation mediated inflammatory cytokine production in a clinical setting.

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.

Interleukin 1alpha activity of peritoneal and bone marrow macrophages infected with Leishmania major and Leishmania donovani in vitro

In this study, the pattern of interleukin-1alpha (IL-1alpha) production by both peritoneal (PM) and bone marrow macrophages (BMM) from resistant (C3H/HeJ) and susceptible (BALB/c) mice was investigated, using a bioassay and an IL-1alpha-specific ELISA kit. PM from normal uninfected mice showed either an initial high (C3H/HeJ) or a neglected (BALB/c) level of IL-1alpha activity, respectively, probably due to thioglycollate stimulation. Infection with Leishmania major induced only a marginal effect on IL-1 production by both cells. Normal, uninfected and unstimulated BMM from both mice did not produce IL-1alpha over a 7-day period of cultivation in vitro. Upon stimulation with either lipopolysaccharide (LPS) (BALB/c) or concanavalin A (Con A) (C3H/HeJ), both cell types produced IL-1alpha that peaked within the first 12-24 h following stimulation. BMM from C3H/HeJ and BALB/c mice failed to produce IL-1alpha when infected in vitro with L. major or L. donovani promastigotes. However, infection with these two parasites did not interfere with the capability of the host cell to produce IL-1alpha when stimulated with LPS or Con A. The level of IL-1alpha production was independent of the degree of parasitization of the macrophages. Similar results were observed with IL-1beta and IL-6 production by BMM, even though their levels were generally slightly higher than those obtained with IL-1alpha.

Risk-benefit assessment of methotrexate in the treatment of severe psoriasis

Methotrexate is an established and highly effective systemic treatment for severe psoriasis, including the pustular and erythrodermic forms. It has been widely used during the last 3 decades. For this reason, the long term adverse effects of methotrexate are well known, in contrast to other relatively new systemic treatments like cyclosporin and retinoids. The most frequent adverse effects occurring during methotrexate therapy are abnormal liver function tests, nausea and gastric complaints. The most feared adverse effects are myelosuppression and hepatotoxicity. Because hepatotoxicity is related to a high cumulative dose of methotrexate, rotational therapy or an intermittent instead of a continuous treatment schedule are advised. The histological assessment of liver biopsies, according to the international guidelines, remains the gold standard for detection of liver damage until equally reliable noninvasive screening methods for liver damage--tentatively dynamic hepatic scintigraphy (DHS) or measurement of levels of serum aminoterminal propeptide of type III procollagen--are well evaluated. Low dose methotrexate therapy is relatively well tolerated, provided that there is careful patient selection and regular monitoring for adverse effects and drug interactions during methotrexate therapy is carried out. The long term clinical efficacy and relative safety of methotrexate remain impressive.

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.

Methotrexate and leflunomide: biochemical basis for combination therapy in the treatment of rheumatoid arthritis

OBJECTIVES

Methotrexate is currently one of the most widely prescribed disease-modifying antirheumatic drugs (DMARDs) for the treatment of rheumatoid arthritis (RA). Combination therapy of methotrexate with other DMARDs increases the clinical success of low-dose methotrexate treatment. Leflunomide is a new DMARD that may have a high potential for success in combination therapy with methotrexate. This review compares the mode of action of methotrexate and leflunomide and speculates on how this contributes to therapeutic efficacy in RA when these agents are used singly or in combination.

METHODS

A literature review of the biochemical mechanisms considered to be the basis for the therapeutic efficacy of methotrexate and leflunomide in treating RA is presented.

RESULTS

Low-dose methotrexate inhibits cytokine production, purine biosynthesis, and, in an animal model, causes the release of adenosine, a potent antiinflammatory agent. Leflunomide, through inhibition of de novo pyrimidine biosynthesis, can regulate lymphocyte proliferation.

CONCLUSIONS

The biochemical mechanisms underlying the therapeutic efficacy of low-dose methotrexate and leflunomide in the treatment of RA are quite different. The potentially complementary mechanisms of action of these two effective DMARDs should provide a rationale for their use in combination therapy for patients whose condition no longer responds to methotrexate alone.

Molecular and cellular effects of methotrexate

In 1998, knowledge about the mechanisms of action of methotrexate (MTX) in immunoinflammatory disorders further increased. The most interesting results to date came from studies showing that most of the anti-inflammatory actions of MTX are mediated by adenosine, which may account for the profound effects of MTX on cytokines, cytokine inhibitors, and cell differentiation. Finally, potential novel pharmacologic strategies are discussed based on actual knowledge about the molecular and cellular actions of MTX.

Newer therapeutic agents for asthma

The past decade has seen significant advances in the available treatments for asthma. These include longer-acting bronchodilating agents, high topical potency inhaled corticosteroids, and agents that interfere with leukotriene production or action. Table 3 summarizes the clinical effects of the newer therapeutic agents reviewed. Experimental therapies for the steroid-dependent patient have also been discussed. Although clinical trials to date have established many of these as effective in asthma, the results of ongoing, large, multicenter studies investigating the relative merits of these therapies, alone and in combination, will further clarify how to maximize the utility of these agents in the treatment of asthma.

Methotrexate specifically modulates cytokine production by T cells and macrophages in murine collagen-induced arthritis (CIA): a mechanism for methotrexate-mediated immunosuppression

Immunosuppressive therapy with methotrexate (MTX) has been established as effective treatment for patients with rheumatoid arthritis. To analyse the therapeutic potential and mechanisms of action of MTX, we determined serum cytokine levels and cytokine production by splenic T cells and macrophages in untreated and MTX-treated mice. Furthermore, we assessed the role of MTX in a murine model of experimental arthritis induced by collagen type II (CIA). MTX reduced spontaneous and IL-15-induced tumour necrosis factor (TNF) production by splenic T cells but not by macrophages from healthy mice in vitro in a dose-dependent manner. In contrast, interferon-gamma (IFN-gamma) production was less strikingly reduced and IL-4 production was virtually unaffected. In addition, treatment of healthy mice with MTX in vivo led to reduced TNF serum levels and diminished TNF production by splenic T cells and macrophages. Intraperitoneal administration of MTX prior to the onset of arthritis completely prevented clinical and pathological signs of CIA. This was associated with a striking reduction of TNF production by spleen cells from MTX-treated mice. The role of TNF in MTX-mediated effects on cytokine production was further underlined by the finding that MTX effects on IFN-gamma production were augmented in TNF-transgenic mice but abrogated in mice in which the TNF-alpha gene had been inactivated by homologous recombination. Thus, MTX specifically modulates spontaneous and IL-15-induced TNF-alpha production in mice and prevents experimental murine CIA. These data suggest that TNF production by T cells is an important target of MTX and may serve as a basis to understand and further analyse MTX-mediated mechanisms of immunosuppression in patients with RA.

Successful methotrexate therapy for adult Still's disease with marked thrombocytopenia

A 34-year-old Japanese woman developed spiking fever, splenomegaly, arthritis, neutrophilia, hyperferritinaemia (22517 ng/ml), elevated C-reactive protein (9.1 mg/ml) and severe thrombocytopenia (1.7 x 10(4)/microl). The patient had depressed antithrombin III activity and abnormally high concentrations of both fibrin degradation products and thrombin-antithrombin complexes. This condition was resistant to high-dose prednisolone therapy (120 mg/day) and non-steroidal anti-inflammatory drugs. We initiated oral methotrexate therapy (7.5 mg/week, orally) with a favourable outcome. The patient's spiking fever subsided on the first day of methotrexate administration. Elevated levels of ferritin and C-reactive protein in the sera rapidly normalised. Methotrexate rapidly improved the disease state which suggested that methotrexate act via modulation of cytokine production or secretion.

Effects of methotrexate on normal articular cartilage in vitro and in vivo

OBJECTIVE

Methotrexate (MTX) has become the disease modifying drug of choice for the treatment of rheumatoid arthritis (RA). Direct effects of MTX on articular cartilage in vivo and in vitro were studied to determine possible adverse effects of the drug.

METHODS

For in vitro experiments, adult bovine articular cartilage explants were cultured in the presence of MTX (0 to 100 microM), and effects on DNA and matrix metabolism were studied. For in vivo studies, 48 adult female rabbits were treated with MTX (30 mg/kg/week intramuscularly) or placebo, respectively, for up to 12 weeks, and effects on the cartilage of the femoral condyles were assessed.

RESULTS

In vitro, MTX dose dependently increased the uptake of [3H]-thymidine, and decreased incorporation of [3H]-d-uridine into chondrocytes with a half maximal effect at 0.03 microM, suggesting inhibition of thymidylate-synthetase activity by the drug. MTX also dose dependently reduced the proportion of chondrocytes in S-phase, as determined by flow cytometry. MTX did not affect LDH release from chondrocytes or the proportion of viable cells, nor did it change the rate of protein synthesis, proteoglycan synthesis, proteoglycan breakdown, or the hydrodynamic size of newly synthesised proteoglycans. In vivo, MTX did not appreciably affect proteoglycan synthesis of the chondrocytes, proteoglycan content of the cartilage matrix, density of the chondrocyte population, or histological integrity of the cartilage.

CONCLUSIONS

The data suggest the absence of major adverse effects by MTX on articular cartilage proteoglycan metabolism. Chondrocyte DNA metabolism seems to be changed by MTX only in concentrations and exposition periods clearly exceeding those found in synovial fluid of RA patients receiving the commonly prescribed doses of the drug.

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.

Methotrexate suppresses nitric oxide production ex vivo in macrophages from rats with adjuvant-induced arthritis

We examined the effects of methotrexate (MTX) on the level of nitric oxide (NO) produced by peritoneal macrophages from rats with adjuvant-induced arthritis (AA) ex vivo. During the development of AA, paw swelling increased and LPS enhanced the capacity of peritoneal macrophages to produce NO and prostaglandin E2 (PGE2). MTX (0.1 mg/kg, p.o.) treatment for 21 days reduced the paw swelling, and inhibited the increased NO and PGE2 production. However, when MTX (0.1 mg/kg, p.o.) was administered to rats with established AA, these parameters were not significantly influenced. In normal rats, MTX (0.1 mg/kg, p.o.) treatment for 21 days did not change NO and PGE2 production of LPS-stimulated macrophages. On the other hand, macrophages from normal and AA rats cultured in the presence of MTX (1, 10 and 100 microM), were activated by LPS in vitro. MTX did not influence NO or PGE2 production by LPS-stimulated macrophages in normal and AA rats. By contrast, indomethacin (IM) (1.0 mg/kg, p.o.) treatment for 21 days reduced the paw swelling, and inhibited NO and PGE2 production in AA rats. IM inhibited significantly PGE2 production, but did not influence NO production by LPS-stimulated macrophages in vitro. These results suggest that MTX treatment reduces NO production in peritoneal macrophages in AA rats, and these actions of MTX may have an inhibitory effect without the modulation of PGE2.

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.

In vitro effect of gold sodium thiomalate and methotrexate on tumor necrosis factor production in normal healthy individuals and patients with rheumatoid arthritis

We studied the in vitro action of gold sodium thiomalate (GSTM) and Methotrexate (MTX) on spontaneous and lipopolysaccharide (LPS) stimulated TNF alpha production by peripheral blood mononuclear cells (PBMC) of patients with rheumatoid arthritis (RA) and normal healthy individuals. GSTM and MTX (10 microg) each were added to the cultures of PBMC either in medium alone (spontaneous) or in the presence of 10 microg of LPS. GSTM and MTX augmented spontaneous TNF alpha production in normal individuals and patients with RA but did not influence LPS stimulated TNF alpha production. However, TNF alpha production by the PBMC of normal individuals was inhibited if the PBMC were stimulated with LPS, for 6 or 12 h, washed to remove LPS and subsequently incubated with GSTM. These data indicate that GSTM can inhibit TNF alpha production when the PBMC are preactivated by LPS.

The effect of methotrexate on the expression of a cysteine protease inhibitor (type 2 cystatin) in rat sebaceous glands

The purpose of this study was to assess whether rat cystatin S, a cysteine proteinase inhibitor, is present in rat sebaceous glands, and to measure the effects of methotrexate on the expression of cystatin in these glands. With methotrexate treatment, the number of skin sebaceous cells expressing cystatin increased from 13.9% to 34.3% (P < .05). A smaller increase (from 15.3% to 23.9%; P = .1) was observed in Zymbal sebaceous glands. Type 2 cystatin could not be detected in the major salivary glands, nor in trachea, lung, stomach, small intestine, large intestine, spleen, liver, kidney, or pancreas, in any of the rats given either saline or methotrexate. Our results suggest that type 2 cystatin is a constituent of normal sebaceous glands, and that the amount of cystatin present in these glands increases with methotrexate administration. We speculate that, in addition to the protective functions ascribed to sebaceous lipids, sebum may augment the physical barrier of skin through secretion of cysteine proteinases that may be pharmacologically modulated.