Metallothionein induction by nonsteroidal antiinflammatory drugs

In the present study we report on the effects of commonly used nonsteroidal antiinflammatory drugs on metallothionein (MT) and MT-I mRNA levels. A single dose of chloroquine (100 mg/kg), diclofenac (100 mg/kg), indomethacin (10 mg/kg), or piroxicam (100 mg/kg) was administered ip to C57B1 mice. After 18 h, MT levels were determined with a Cd-saturation radioassay. MT-I mRNA levels were measured by Northern Blot analyses using a probe containing the mouse MT-I gene. All drugs tested caused an increase in the MT content of the liver but not of the kidneys and lung. The lowest and highest effects were observed with chloroquine (8 times the control value) and diclofenac (18 times), respectively. In accordance with the stimulation of MT synthesis, increased accumulation of hepatic MT-I mRNA could be demonstrated. These results indicate that elevated MT levels may contribute to the effectiveness of nonsteroidal antiinflammatory drugs in the treatment of rheumatoid arthritis (RA).     

Soybean lipoxygenase inhibition by nonsteroidal antiinflammatory drugs

Eighteen known nonsteroidal antiinflammatory drugs (NSAID) were tested for their action against soybean lipoxygenase (E.C.1.13.11.12) using linoleic acid as substrate. It was found that the best inhibitors of lipoxygenase were naproxen, BW 755C, indomethacin and isoxicam. Drugs with intermediate potency were meclofenamic acid, phenyl-butazone and benoxaprofen. Other drugs such as ibuprofen and zomepirac were only weakly active in the test.     

Inhibition of intestinal peroxidase activity by nonsteroidal antiinflammatory drugs

The peroxidase activity of the mitochondrial fraction of rat intestine is inhibited in vitro by non-steroidal antiinflammatory drugs (NSAIDs), such as indomethacin (IMN) and acetylsalicylic acid (ASA), the former being more potent than the latter. The peroxidase was solubilised by cetab-NH₄Cl extraction and purified to apparent homogeneity by Sephadex G-150 gel filtration and affinity chromatography on Con-A Sepharose. The purified enzyme activity was 80% inhibited by 150 μM IMN and 50% by 2.67 mM ASA. IMN could also inhibit lactoperoxidase activity to the same extent but not the horseradish peroxidase activity. The inhibition of peroxidase-catalysed iodide oxidation by IMN and ASA was optimal at pH 5.5 and 4.5, respectively. Kinetic studies revealed that the inhibition by IMN was competitive with respect to iodide or guaiacol, while the inhibition by ASA was noncompetitive and reversible in nature. Studies of some structural analogues showed that indole-3-acetic acid was as effective as IMN, while salicylic acid was more potent than ASA. Spectral studies showed a small bathochromic shift of the Soret band of the enzyme by IMN, suggesting its possible interaction at or near the heme moiety. The competitive nature of IMN may be explained as due to its oxidation by the peroxidase to a product absorbing at 412 nm, the formation of which is inhibited by iodide. We suggest that IMN inhibits intestinal peroxidase activity by acting as a competitive substrate for the enzyme. As intestinal peroxidase is mainly contributed by the invading eosinophils, NSAIDs may affect the host defence mechanism by inhibiting the activity of the enzyme.     

Signal peptide peptidase: biochemical properties and modulation by nonsteroidal antiinflammatory drugs

Signal peptide peptidase (SPP) is an intramembrane aspartyl protease that cleaves remnant signal peptides after their release by signal peptidase. SPP contains active site motifs also found in presenilin, the catalytic component of the gamma-secretase complex of Alzheimer's disease. However, SPP has a membrane topology opposite that of presenilin, cleaves transmembrane substrates of opposite directionality, and does not require complexation with other proteins. Here we show that, upon isolation of membranes and solubilization with detergent, the biochemical characteristics of SPP are remarkably similar to gamma-secretase. The majority of the SPP-catalyzed cleavages occurred at a single site in a synthetic substrate based on the prolactin (Prl) signal sequence. However, as seen with cleavage of substrates by gamma-secretase, additional cuts at other minor sites are also observed. Like gamma-secretase, SPP is inhibited by helical peptidomimetics and apparently contains a substrate-binding site that is distinct from the active site. Surprisingly, certain nonsteroidal antiinflammatory drugs known to shift the site of proteolysis by gamma-secretase also alter the cleavage site of Prl by SPP. Together, these findings suggest that SPP and presenilin share certain biochemical properties, including a conserved drug-binding site for allosteric modulation of substrate proteolysis.     

Inhibition of hepatic 17 beta- and 3 alpha-hydroxysteroid dehydrogenases by antiinflammatory drugs and nonsteroidal estrogens

Antiinflammatory agents and estrogens have been tested as inhibitors of two isozymes of guinea pig liver testosterone 17 beta-dehydrogenase (NADP) 1.1.1.64) and rat liver 3 alpha-hydroxysteroid dehydrogenase (EC 1.1.1.50). Antiinflammatory steroids and estradiols were highly inhibitory to 3 alpha-hydroxysteroid dehydrogenase and one isozyme of testosterone 17 beta-dehydrogenase, respectively, but nonsteroidal antiinflammatory agents and nonsteroidal estrogens such as hexestrol, dienstrol, diethylstilbestrol and zearalenone showed potent inhibitions on all the enzymes. Although the inhibitory potency of indomethacin for one isozymes of testosterone 17 beta-dehydrogenase and 3 alpha-hydroxysteroid dehydrogenase decreased with changing pH from 9.7 to 7.0, that of the nonsteroidal estrogens for all the enzymes was little affected by pH. No additive effect in double inhibitor experiments with indomethacin and the nonsteroidal estrogens was observed, and the compounds were all competitive inhibitors with respect to steroidal substrate. The results suggest that there is a very similar region in substrate binding sites of the enzymes.     

IL-1 beta converting enzyme is a target for nitric oxide-releasing aspirin: new insights in the antiinflammatory mechanism of nitric oxide-releasing nonsteroidal antiinflammatory drugs

Caspase-1, the IL-1beta converting enzyme (ICE), is required for intracellular processing/maturation of IL-1beta and IL-18. NO releasing nonsteroidal antiinflammatory drugs (NSAIDs) are a new class of NSAID derivatives that spare the gastric mucosa. Here, we tested the hypothesis that NCX-4016, a NO-aspirin derivative, inhibits proinflammatory cytokine release from endotoxin (LPS)-challenged monocytes. Our results demonstrated that exposing LPS-stimulated human monocytes to NCX-4016 resulted in a 40-80% inhibition of IL-1beta, IL-8, IL-12, IL-18, IFN-gamma, and TNF-alpha release with an EC(50) of 10-20 microM for IL-1beta and IL-18. Incubating LPS-primed monocytes with NCX-4016 resulted in intracellular NO formation as assessed by measuring nitrite/nitrate, intracellular cGMP concentration, and intracellular NO formation. Exposing LPS-stimulated monocytes to aspirin or celecoxib caused a 90% inhibition of prostaglandin E(2) generation but had no effect on cytokine release. NCX-4016, similar to the NO donor S-nitroso-N-acetyl-D-L-penicillamine, inhibited caspase-1 activity with an EC(50) of approximately 20 microM. The inhibition of caspase-1 by NCX-4016 was reversible by the addition of DTT, which is consistent with S-nitrosylation as the mechanism of caspase-1 inhibition. NCX-4016, but not aspirin, prevented ICE activation as measured by assessing the release of ICE p20 subunit. IL-18 immunoneutralization resulted in a 60-80% reduction of IL-1beta, IL-8, IFN-gamma, and TNF-alpha release from LPS-stimulated monocytes. Taken together, these data indicate that incubating human monocytes with NCX-4016 causes intracellular NO formation and suppresses IL-1beta and IL-18 processing by inhibiting caspase-1 activity. Caspase-1 inhibition is a new, cycloxygenase-independent antiinflammatory mechanism of NO-aspirin.     

Effect of nonsteroidal anti-inflammatory drugs on the microsomal monooxygenase system of rat liver

The effect of acetylsalicylic acid, ibuprofen, indomethacin, ketoprofen, naproxen, phenylbutazone, and salicylic acid on the microsomal oxidative drug metabolism of rat liver was studied. Pretreatment of the rats with pharmacologic doses of acetylsalicylic acid, indomethacin, and ketoprofen decreased both the demethylase and hydroxylase activities of rat liver microsomes. These effects were paralleled by decreases in microsomal cytochrome P-450 content. The rate of the microsomal reactions was increased after pretreatment with ibuprofen and naproxen but only the former increased the concentration of cytochrome P-450. Phenylbutazone and salicylic acid had no in vivo effect on the hepatic monooxygenase. The addition of 1 mM of ibuprofen, indomethacin, ketoprofen, naproxen, and phenylbutazone to rat liver microsomes inhibit both the aminopyrine N-demethylase and p-nitro-anisole O-demethylase activities. The extent of the inhibition varied between 21 and 73% of the control incubation. Indomethacin, naproxen, and phenylbutazone also decreased the aniline hydroxylase activity to roughly 60% of the control value. Acetylsalicylic acid and salicylic acid had no in vitro effect on the microsomal monooxygenase. The nonsteroidal anti-inflammatory drugs produced a reverse type I binding spectrum with oxidized cytochrome P-450; indomethacin and phenylbutazone were the strongest ligands. There is no correlation between the effect of addition of nonsteroidal anti-inflammatory drugs to the hepatic microsomal homogenate and their in vivo effect on the monooxygenase activity.     

Glucocorticoid/antiinflammatory activities of nonsteroidal phenylpyrazoles in the rat

Six nonsteroidal phenylpyrazoles are described that have significant glucocorticoid and antiinflammatory activities. These agents competed with dexamethasone for the glucocorticoid receptor from the rat thymus, suppressed adrenal weight when administered orally to intact female rats, produced liver glycogen deposition and thymolysis when administered orally to adrenalectomized male rats, and reduced cotton granuloma formation when administered in the cotton pellet. In addition, in the latter model, no systemic activity (thymolysis or reduced body weight gain) was seen with doses up to 500 to 5000 times the dose which reduced granuloma formation. At least one compound was more potent than methylprednisolone in three of the four rat assay systems used. The compounds described are structurally different from conventional steroidal glucocorticoids but possessed potent glucocorticoid activities. However, they exhibited antiinflammatory activity without evidence of systemic activity when administered locally.     

Marked disability and high use of nonsteroidal antiinflammatory drugs associated with knee osteoarthritis in rural China: a cross-sectional population-based survey

Introduction  

The burden of disability, analgesia, and health services use associated with knee pain and osteoarthritis (OA) in developing countries is relatively unknown, despite a high proportion of these populations required to be engaged in heavy occupational physical activity throughout their life span. The aim of this survey was to estimate the burden of disability, analgesia, and health services use associated with knee pain in rural China.     

Lysosomal membrane stabilization by antiinflammatory drugs

Lysosomal enzymes are important mediators of acute and chronic inflammatory diseases. The release of lysosomal enzymes into cytoplasm stimulate the inflammatory mediators like oxygen radicals, prostaglandins etc. Enfenamic acid, a fenamate, along with other antiinflammatory drugs, did not stabilize lysosomal membrane isolated from normal and activated phagocytic polymorphonuclear leucocytes of different species.     

Tuberculosis and nonsteroidal anti-inflammatory drugs.

In 1980 and 1982 two case reports documented reactivation of pulmonary tuberculosis in patients who had used nonsteroidal anti-inflammatory drugs (NSAIDs). A case-control study was designed to test the hypothesis that such an association does exist. Data for 38 patients were obtained from the patients'' family physicians, and each patient was matched with a control from the same practice for age, sex, race and length of time in that practice. A statistically significant relation was found between the reactivation of tuberculosis and the use of NSAIDs. However, further research is imperative to determine whether the association is direct, indirect or secondary to an unknown factor. Physicians should keep in mind that NSAIDs are potent anti-inflammatory agents and may thus activate, spread and mask infections.     

Carbachol interactions with nonsteroidal anti-inflammatory drugs

The inhibition of cyclooxygenase enzymes by nonsteroidal anti-inflammatory drugs (NSAIDs) does not completely explain the antinociceptive efficacy of these agents. It is known that cholinergic agonists are antinociceptive, and this study evaluates the interactions between carbachol and some NSAIDs. Antinociceptive activity was evaluated in mice by the acetic acid writhing test. Dose-response curves were constructed for NSAIDs and carbachol, administered either intraperitoneally (i.p.) or intrathecally (i.t.). The interactions of carbachol with NSAIDs were evaluated by isobolographic analysis after the simultaneous administration of fixed proportions of carbachol with each NSAID. All of the drugs were more potent after spinal than after systemic administration. The combinations of NSAIDs and carbachol administered i.p. were supra-additive; however, the i.t. combinations were only additive. Isobolographic analysis of the coadministration of NSAIDs and carbachol and the fact that atropine antagonized the synergistic effect suggest that carbachol may strongly modulate the antinociceptive activity of NSAIDs; thus, central cholinergic modulation would be an additional mechanism for the antinociceptive action of NSAIDs, unrelated to prostaglandin biosynthesis inhibition.     

Inhibition of both COX-1 and COX-2 is required for development of gastric damage in response to nonsteroidal antiinflammatory drugs.

We examined the gastric ulcerogenic property of selective COX-1 and/or COX-2 inhibitors in rats, and investigated whether COX-1 inhibition is by itself sufficient for induction of gastric damage. Animals fasted for 18 h were given various COX inhibitors p.o., either alone or in combination, and they were killed 8 h later. The nonselective COX inhibitors such as indomethacin, naproxen and dicrofenac inhibited PG production, increased gastric motility, and provoked severe gastric lesions. In contrast, the selective COX-2 inhibitor rofecoxib did not induce any damage in the stomach, with no effect on the mucosal PGE(2) contents and gastric motility. Likewise, the selective COX-1 inhibitor SC-560 also did not cause gastric damage, despite causing a significant decrease in PGE(2) contents. The combined administration of SC-560 and rofecoxib, however, provoked gross damage in the gastric mucosa, in a dose-dependent manner. SC-560 also caused a marked gastric hypermotility, whereas rofecoxib had no effect on basal gastric motor activity. On the other hand, the COX-2 mRNA was expressed in the stomach after administration of SC-560, while the normal gastric mucosa expressed only COX-1 mRNA but not COX-2 mRNA. These results suggest that the gastric ulcerogenic property of conventional NSAIDs is not accounted for solely by COX-1 inhibition and requires the inhibition of both COX-1 and COX-2. The inhibition of COX-1 up-regulates the COX-2 expression, and this may counteract the deleterious influences, such as gastric hypermotility and the subsequent events, due to a PG deficiency caused by COX-1 inhibition.     

Enantiomeric resolution of some nonsteroidal antiinflammatory and anticoagulant drugs using β‐cyclodextrins by capillary electrophoresis

β‐cyclodextrin (CD) and its derivatives HP‐β‐CD, DM‐β‐CD, and TM‐β‐CD have been employed as chiral selectors for the separation of three nonsteroidal antiinflammatory drugs (NSAIDs) and anticoagulant at relatively low concentration (8–15 mM) by capillary zone electrophoresis (CZE). In this study, baseline separation was achieved for ibuprofen, ketoprofen, naproxen, and warfarin. It was found that the addition of 0.1% hydroxypropyl methyl cellulose (HPMC) was effective for separation. Under these conditions, the S‐(+) enantiomer eluted before R‐(−) in terms of ibuprofen; the calculated energy values obtained from the molecular modeling correlated well with the elution order. An equation for calculating the pK_a values by capillary electrophoresis was introduced, and the pK_a values of the four chiral drugs at 25°C were obtained based on the equation. The value pK_a + 0.5 is proposed to be the suitable pH of the background electrolyte for the separation of chiral compounds containing a carboxylic group. Chirality 11:56–62, 1999. © 1999 Wiley‐Liss, Inc.     

Effect of drugs on urate binding to plasma proteins

The effect of various drugs on urate binding to plasma proteins was investigated in normal subjects. Whereas allopurinol, aspirin, phenylbutazone, probenecid, and sulphinpyrazone all significantly reduced plasma urate concentrations, only aspirin, phenylbutazone, and probenecid significantly impaired urate binding. Colchicine and indomethacin in the doses administered had no significant effect on plasma urate concentrations or binding. In the case of aspirin, urate binding was reduced to 25% of normal, and this effect was quickly abolished after cessation of therapy. Phenylbutazone reduced urate binding to 56% and probenecid to 46% of normal; this impairment was still detected four days after cessation of therapy. Drugs may impair urate binding by competition for plasma protein binding sites, with displacement of bound urate. Impairment of urate binding in vivo by administration of certain drugs may be relevant to the precipitation of acute gouty arthritis, to the formation of gouty tophi, and to the augmentation of uricosuria. Furthermore, the role of drugs must be seriously considered during all studies on urate binding in patients with gout.