Effects of antirheumatic drugs on the interleukin-1 alpha induced synthesis and activation of proteinases in articular cartilage explants in culture

Three human cytokines (interleukin-1 alpha, interleukin-1 beta and tumor necrosis factor-alpha), added into the medium of bovine or rabbit articular cartilage explant cultures, stimulated the synthesis and activation of various proteinases. Proteoglycan degradation, measured by assaying for sulfated glycosaminoglycans released into the medium, was correlated with the proteinase stimulation. Several antirheumatic drugs were tested in a similar tissue culture system as potential inhibitors of the interleukin-1 alpha mediated stimulation of proteinase and PGE2 syntheses. Arteparon, Dexamethasone, Ibuprofen, Indomethacin, Levamisole, Naproxen, Phenylbutazone, Prednisolone, Piroxicam, Rumalon, Tamoxifen and Diclofenac were essentially ineffective in inhibiting the interleukin-1 alpha mediated induction of proteinase synthesis and sulfated glycosaminoglycan release, although some of them inhibited PGE2 synthesis. Two antimalarial drugs showed some inhibition, but only at higher concentrations.     

Adverse cardiovascular effects of antirheumatic drugs: implications for clinical practice and research

Clinical manifestations of most rheumatic diseases have changed over the past few decades, largely due to advances in therapies targeting autoimmune and (auto)inflammatory pathways. Improvements in the management of rheumatic diseases have also now brought to the fore the issue of comorbidities. It has become evident that the burden of cardiovascular morbidity and mortality is increased in rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and the spondyloarthropathies, amongst other conditions. As a result, efforts have switched toward investigating the effects of conventional antirheumatic and new biologic agents on inflammationinduced atherothrombosis. Evidence is accumulating suggesting a beneficial cardiovascular profile of some antirheumatic drugs, such as methotrexate and hydroxychloroquine, but it also indicates the possibility of a variety of adverse events developing in the short- and long-term. The aim of this review is to highlight cardiovascular adverse effects of the drugs widely used in the treatment of rheumatic diseases. The literature search was performed through PubMed, the Cochrane Library, Scopus, and Web of Science databases using the following terms: "antirheumatic drugs", "inflammation", "rheumatic diseases", "cardiovascular diseases", "adverse events", "toxicity", "drug design", and "drug interactions". Adverse events ranging from infusion-related hypertension and myocardial ischemia, to restrictive cardiomyopathy and congestive heart failure have been reported in large trials and case series on most antirheumatic drugs. Clinicians should be alert of the wide variety of cardiovascular adverse effects of individual antirheumatic drugs, and should carefully monitor blood pressure and markers of inflammation, thrombosis, myocardial ischemia, electrolytes, and lipid disturbances while administering these drugs. Future prospective studies should specifically investigate the cardiovascular safety of most antirheumatic drugs as part of mono- or combination therapy in relation to different dosage regimens, duration of therapy, age, and gender.     

Delayed hypersensitivity to tuberculin in rats: effects of antirheumatic drugs.

The effects of different antirheumatic drugs administered according to various dosing regimes on tuberculin hypersensitivity in rats have been assessed quantitating the changes of exudate volume and mononuclear cells immigration at the site of challenge. Dosing at the time of sensitization with aurothiomalate and D-penicillamine enhanced the cell immigration which was decreased by similar treatment with levamisole. Cyclophosphamide increased the exudate formation. Indomethacin had no effect. Dosing at the time of challenge caused a marked reduction of both the parameters by aurothiomalate and cyclophosphamide and enhancement by levamisole. D-penicillamine increased only the cellular immigration and indomethacin the exudate formation. Long treatment with aurothiomalate and cyclophosphamide suppressed the responses. Similar treatment with D-penicillamine and levamisole produced a significant enhancement. Indomethacin had no effect. The relevance of these findings to the testing and mode of action of antirheumatic drugs is discussed.     

Limits of add-on trials: antirheumatic drugs

Purpose  This paper assesses the design of clinical studies used in the process of regulatory approval, focusing on how add-on studies affect regulatory decisions. Methods  The sample case taken is that of the new agents for rheumatoid arthritis (RA) authorised by the European Medicine Agency (EMEA). The European Public Assessment Reports (EPARs) accompanying the marketing authorisations were the source of information on the studies presented in the registration dossiers. Results  The recently approved anti-RA agents are all indicated in combination with methotrexate (MTX) for treating adults with active RA who have responded inadequately to disease-modifier drugs (DMARDs). The add-on design was frequently used in registration studies. For infliximab, etanercept, adalimumab and rituximab, add-on trials contributed, together with parallel-group trials, to gaining the approval as combination therapy. Anakinra and abatacept were authorised on the basis of add-on trial results only. Conclusions  Add-on trials do not allow assessment of the intrinsic efficacy and safety of new agents and their value as alternatives to available treatments. The indications granted for the new anti-RA agents do not specify whether newer drugs can replace standard treatments in nonresponders, can do better in the overall patient population or can be used as first-line treatment.     

Alteration of interleukin-1 activity and the acute phase response in adjuvant arthritic rats treated with disease modifying antirheumatic drugs

Interleukin-1 (IL-1) activity and the acute phase response, as measured by plasma CRP and iron, were used to determine if the standard disease modifying antirheumatic drugs (DMARDs), gold, chloroquine and D-penicillamine had a common profile of activity in the adjuvant arthritic (AA) rat. All drugs were tested at a dose which significantly reduced noninjected paw swelling in AA rats. Inhibition of paw edema ranged from 37% for D-penicillamine (100 mg/kg) to 69% for auranofin (10 mg/kg). Two week medication of AA rats with gold sodium thiomalate (GST, 10 mg/kg, i.m.) or auranofin (10 mg/kg, p.o.) resulted in a significant decrease in splenic IL-1 activity, as measured in the standard lymphocyte activating factor (LAF) assay. The acute phase response, often associated with elevated IL-1 activity, was also significantly reduced following treatment of AA rats with 10 mg/kg of GST or auranofin (oral gold). Inhibition of the acute phase response by gold was determined by a significant reduction of plasma CRP levels (56-71% reduction) and enhancement of plasma iron levels (27-52% enhancement). In contrast to the effect of GST and auranofin on IL-1, CRP and iron, treatment with chloroquine (20, 30 and 35 mg/kg) and D-penicillamine (55 and 100 mg/kg) failed to reduce the acute phase response (as measured by plasma CRP and iron) or alter LAF activity from AA rat spleen cell supernatants. Based on its ability to reduce LAF activity in spleen cell supernatants and reduce the acute phase response, it is possible that the activity of gold in the AA rat may in part be due to its ability to inhibit IL-1 production in vivo. The inability of chloroquine and D-penicillamine to alter LAF activity and the acute phase response in AA rats does not preclude their possession of an immunoregulatory mechanism of action, but it does indicate that their mechanism of action in the AA rat probably differs from that of GST and auranofin.     

Co-mitogenic assay for assessing the effects of aflatoxin B1 on interleukin-1 production in bovine macrophages

Previous research has shown that aflatoxin B₁ (AFB₁) markedly decreases the uptake of tritiated thymidine in bovine peripheral lymphocytes. Currently, the immunosuppressive activities of aflatoxin B₁ are being investigated further using bovine macrophages as a model cell type. Polystyrene-adhered macrophages demonstrated a 50% reduction in up-take of tritiated thymidine at 10 μg/mL aflatoxin B₁. The distribution of ³H-AFB₁ in bovine macrophages was investigated to study mechanisms by which AFB₁ may be exerting immunosuppressive effects. Only 12.96% of the incorporated ³H-AFB₁ was taken into nuclear DNA, whereas 80.13% remained in the cytosolic fraction. A co-mitogenic assay was developed to ascertain the correlation between reduced tritiated thymidine uptake, binding of ³H-AFB₁ to nuclear DNA, and interleukin-1 (IL-1) production and/or activity. Conditioned media containing interleukin-1 activity was prepared by culturing macrophages for 24 hr with 2.5 μg/mL lipopolysaccharide, 45 ng/mL phorbol myristate acetate, with or without 10 μg/mL aflatoxin B₁. The conditioned media was used in a co-mitogenic assay with calf thymocytes as target cells. In this assay, the response of calf thymocytes to conditioned media from AFB₁-treated cells did not differ from the response to control conditioned media. In addition, AFB₁ added to thymocyte cultures co-stimulated with conditioned media and concanavalin A (ConA) greatly diminished the thymocyte response to co-stimulation. The data support the conclusions that the immunosuppressive effects of AFB₁ on the bovine macrophage and T lymphocyte may not be directly related via impaired IL-1 production. The blinding of AFB₁ to macrophage DNA was not sufficient to produce any detectable effect on interleukin-1 production by bovine macrophages.     

Surface plasmon resonance based assay for the detection and characterization of promiscuous inhibitors

Promiscuous binders achieve enzyme inhibition using a nonspecific aggregation-type binding mechanism to proteins. These compounds are a source of false-positive hits in biochemical inhibition assays and should be removed from screening hit lists because they are not good candidates to initiate medicinal chemistry programs. We introduce a robust approach to identify these molecules early in the lead generation process using real time surface plasmon resonance based biosensors to observe the behavior of the binding interactions between promiscuous compounds and proteins. Furthermore, the time resolution of the assay reveals a number of distinct mechanisms that promiscuous compounds employ to inhibit enzyme function and indicate that the type of mechanism can vary depending on the protein target. A classification scheme for these compounds is presented that can be used to rapidly characterize the hits from high-throughput screens and eliminate compounds with a nonspecific mechanism of inhibition.     

A modification of rat adjuvant arthritis for testing antirheumatic drugs

An inflammation having an acute and a prolonged phase was induced by the injection of carrageenan into the paw of rats inoculated with adjuvant 6 days previously (adjuvant-carrageenan-induced inflammation, ACII). Steroidal and acidic non-steroidal anti-inflammatory drugs were effective on both phases. Basic non-steroidal antiinflammatory drugs were effective only on the acute phase, and cytotoxic drugs only on the prolonged phase. Neither gold nor chloroquine preparations inhibited either phase. Effectiveness of drugs on the acute phase was similar to that on carrageenan oedema. Inhibitory effects of drugs on the prolonged phase were similar to those on the secondary lesions of adjuvant arthritis. The ACII test is considered to have advantages compared with the adjuvant arthritis test in duration of drug administration, in the measurement of intensity of inflammation, in the time for experiment and in analysing the action of drugs.     

Disease-modifying antirheumatic drugs in pregnancy: current status and implications for the future.

Drug use during pregnancy is sometimes unavoidable, especially in chronic inflammatory diseases such as rheumatoid arthritis (RA). The use of disease-modifying antirheumatic drugs (DMARDs) often starts in the early stage of RA; therefore, women of reproductive age are at risk for exposure to a DMARD at time of conception as well as during pregnancy. The aim of this paper was to review recent literature about DMARDs used for rheumatic diseases in pregnancy and to describe the type of study designs and results reported.Twenty-nine studies; eight on hydroxychloroquine/chloroquine, thirteen on methotrexate, three on sulfasalazine and six on azathioprine were identified. With respect to hydroxychloroquine, most studies concluded that it could be safely used in systemic lupus erythematosus or RA. The same conclusions were drawn from the azathioprine studies, but the available evidence is scarce. Although the evidence regarding the safety of methotrexate during pregnancy is conflicting, a high rate of pregnancy losses indicates a risk to the fetus. For each individual case it must be decided whether the benefits outweigh the potential risks. No major teratogenic effects of sulfasalazine were seen although teratogenic effects still can not be excluded. For all other DMARDs, the information on their use in pregnancy was limited.This review underscores the gross absence of data on safety and risks of DMARD use during conception and pregnancy. While young women use these drugs in pregnancy, this review stresses the importance of good monitoring and further research.     

The effect of antirheumatic drugs on collagenolytic activity of cathepsin B1.

Seven antirheumatic drugs were tested for their possible inhibition of collagenolytic activity of cathepsin B1. Arteparon, Antilysin, Sanocrysin and phenylbutazone were found to be potent inhibitors of collagenolytic activity of cathepsin B1. Indomethacin and flufenamic acid were weak inhibitors, flurbiprofen was ineffective. A possible mechanism of action is discussed.     

Thio- and oxoflavopiridols, cyclin-dependent kinase 1-selective inhibitors: synthesis and biological effects

Flavopiridol analogues, thio- and oxoflavopiridols which contain a sulfur (16) or oxygen (18) atom linker between a chromone ring and the hydrophobic side chain, are selective cyclin-dependent kinase 1 (CDK1) inhibitors with an IC(50) of 110 and 130 nM. These analogues were prepared from key intermediate 7 by substituting the ethyl sulfoxide. Enantio pure intermediate piperidone 10 was obtained from the racemic piperidone 8 via a very efficient "dynamic kinetic resolution" in 76% yield. Hydrophobic side chains such as chlorophenyl or tert-butyl produced potent CDK1 inhibitory activity, while hydrophilic side chains such as pyrimidine or aniline caused a severe reduction in CDK inhibitory activity. These analogues are competitive inhibitors with respect to ATP, and therefore activity was dependent upon the CDK subunit without being affected by the cyclin subunit or protein substrate. Thio- and oxoflavopiridols 16 and 18 are not only selective within the CDK family but also discriminated between unrelated serine/threonine and tyrosine protein kinases. CDK1 selective thio- and oxoflavopiridol analogues inhibit the colony-forming ability of multiple human tumor cell lines and possess a unique antiproliferative profile in comparison to flavopiridol.     

An ESR and HPLC-EC assay for the detection of alkyl radicals

The correlation of lipid peroxidation with release of alkanes (RH) is considered a noninvasive method for the in vivo evaluation of oxidative stress. The formation of RH is believed to reflect a lipid hydroperoxide (LOOH)-dependent generation of alkoxyl radicals (LO*) that undergo beta-scission with release of alkyl radicals (R*). Alternatively, R* could be spin-trapped with a nitrone before the formation of RH and analyzed by ESR. Extracts from the liver and lung of CCl(4)- and asbestos-treated rats that were previously loaded with nitrones exhibited ESR spectra suggesting the formation of iso-propyl, n-butyl, ethyl, and pentyl radical-derived nitroxides. In biological systems, various nitroxides with indistinguishable ESR spectra could be formed. Hence, experiments with N-tert-butyl-alpha-phenylnitrone (PBN) for spin trapping of R* were carried out in which the nitroxides formed were separated and analyzed by HPLC with electrochemical detection (EC). The C(1-5) homologous series of PBN nitroxides and hydroxylamines were synthesized, characterized by ESR, GC-MS, and HPLC-EC, and used as HPLC standards. For in vivo generation and spin trapping of R*, rats were loaded with CCl(4) and PBN. The HPLC-EC chromatograms of liver extracts from CCl(4)-treated rats demonstrated the formation of both the nitroxide and hydroxylamine forms of PBN/*CCl(3), as well as the formation of a series of unidentified PBN nitroxides and hydroxylamines. However, formation of PBN adducts with retention times similar to these of the PBN/C(2-5) derivatives was not observed. In conclusion, we could not correlate the production of PBN-detectable alkyl radicals with the reported CCl(4)-dependent production of C(1-5) alkanes. We speculate that the major reason for this is the low steady-state concentrations of R* produced because only a small fraction of LO* undergo beta-scission to release R*.     

Role of interleukin-1 inhibitors in osteoarthritis: an evidence-based review

Osteoarthritis (OA), the most common chronic musculoskeletal disease, represents a leading cause of disability in the elderly population worldwide. At present, there is no aetiological treatment for OA patients. Also, current therapeutic regimens for OA are only partially effective, and that is the main reason for most physicians' complaints. Therefore, one of the biggest challenges in the future will be to find the most appropriate therapy or therapies for OA. Currently, there are three basic modalities of treatment: nonpharmacological, pharmacological and surgical. Regarding pharmacological treatment, numerous molecular pathways involved in the pathophysiology of OA have been investigated as potential therapeutic targets. In preclinical and clinical trials, many compounds and agents have been tested, and some of them have already shown positive effects on the progression of knee and/or hip OA. One such possible pharmacological treatment of OA is anticytokine therapy. Interleukin-1 (IL-1), as a main inflammatory and catabolic cytokine in the pathophysiology of OA, represents one of the possible treatment targets. For specific inhibition of IL-1 production or activity, various treatment strategies could be used. These include the inhibition or modification of IL-1 action through the application of IL-1 receptor antagonist proteins, soluble IL-1 receptors, monoclonal antibodies against IL-1 or against IL-1 receptor I, blocking the formation of active IL-1β, blocking the IL-1 cellular signalling pathways, or using gene therapy. All the above mentioned treatment strategies for specific inhibition of IL-1 production or activity have been investigated in numerous preclinical and clinical studies. Some of these investigations led to the discovery of new potential drugs for the treatment of OA. However, the results of treatment with these drugs were not entirely satisfactory, and further research is required to achieve the desired goals of therapy.     

Action of antirheumatic drugs on the function of human leucocytes

The effect of 4 antirheumatic drugs, used in the basic therapy of patients with rheumatoid arthritis, on the cellular function of human leucocytes has been studied in vitro. Chloroquine and gold salt aurothioglucose inhibited in a dose-related manner the chemotaxis of polymorphonuclear neutrophils (PMN) and monocytes at therapeutic concentrations. D-Penicillamine only reduced migration of monocytes, but not that of PMN. Chloroquine has been found to suppress the phagocytosis and the microbicide effect of PMN, the transformation of T-lymphocytes and the chemotactic locomotion of the cells in similar concentrations. On the contrary, the concentrations of the gold salt and D-penicillamine inhibitory in these activities were substantially higher than those required for prevention of chemotaxis in vitro. Levamisole, known for immunostimulatory properties in patients, reduced the responsiveness of the leucocytes only at the highest dosage. The relevance of these experimental findings for the therapeutic approach and for their interaction with the host's defense mechanisms has been discussed.     

Cyclooxygenase inhibitors: drugs for cancer prevention

Evidence that chronic intake of non-steroidal anti-inflammatory drugs, especially aspirin, prevents cancer development continues to accumulate. The data are particularly convincing for colorectal cancer; however, because of well-known side effects, they cannot routinely be recommended for this purpose. An appreciation of the mechanisms that underlie their anti-cancer effects might permit the development of safer agents. Intensive investigation has led to the characterization of several potential chemopreventive mechanisms of action of these drugs. Antineoplastic actions could result from effects on overlapping processes in the different cell-types that comprise tumors, such as epithelial and stromal cells.