Anti-inflammatory drugs, prostaglandins and leucocyte migration

Melatonin ameliorates chronic copper-induced lung injury

Copper (Cu) is an important trace element required for several biological processes. The use of copper is increasing gradually in several applications. Previous studies suggest that excess levels of copper are attributed to induce oxidative stress and inflammation, mediating tissue damage. Inline, melatonin the hormone of darkness has been reported to exhibit various therapeutic effects including strong free radical scavenging properties and anti-inflammatory effects. However, its effects against pulmonary injury promoted by copper are not explored and remain unclear so far. Therefore, the present study was aimed to investigate the protective effect of melatonin against copper-induced lung damage. Female Sprague Dawley (SD) rats were exposed to 250 ppm of copper in drinking water for 16 weeks and treated with melatonin (i.p.) 5 and 10 mg/kg from the week (13-16th). The extent of tissue damage was assessed by tissue oxidative stress parameters, metal estimation and histological analysis. Copper-challenged rats showed altered oxidative stress variables. In addition, metal analysis revealed increased copper accumulation in the lungs and histological staining results further indicated severe tissue injury and inflammatory cell infiltration in copper-exposed rats. To this side, treatment with melatonin showed antioxidant and anti-inflammatory activities evidenced by reduced oxidative stress, tissue inflammation and collagen deposition as compared to copper-exposed animals. Moreover, spectral findings suggested melatonin treatment modulated the frequency sift, as compared to copper-challenged animals. Altogether, the present results suggest that melatonin might play a potential role in preventing copper-induced lung aberrations via inhibiting the ROS-mediated oxidative stress and inflammation.

Sulfonic acid functionalized zirconium-based metal–organic framework for the selective detection of copper(ii) ions

A sulphonic acid functionalized Zr(iv) MOF probe was used for the rapid, sensitive and selective sensing of Cu2+.

Lipid Formulations and Bioconjugation Strategies for Indomethacin Therapeutic Advances

Indomethacin (IND) is a drug which after successful clinical trials became available for general prescription in 1965 and from that time is one of the most widely used anti-inflammatory drug with the highest potencies in the in vitro and in vivo models. However, despite its high therapeutic efficacy in relieving the symptoms of certain arthritis and in treating gout or collagen diseases, administration of IND causes a number of adverse effects, such as gastrointestinal ulceration, frequent central nervous system disorders and renal toxicity. These obstacles significantly limit the practical applications of IND and make that 10-20% of patients discontinue its use. Therefore, during the last three decades many attempts have been made to design novel formulations of IND aimed to increase its therapeutic benefits minimizing its adverse effects. In this review we summarize pharmacological information about IND and analyze its new lipid formulations and lipid bioconjugates as well as discuss their efficacy and potential application.

[The therapy of pain in rheumatic joint-and spine diseases.]

The therapy of pain caused by rheumatic diseases above all must take into consideration the cause of the pain. In rheumatoid arthritis, especially in the early stages, inflammation is the primary cause of the pain. The pain decreases the inflammation subsides following the administration of non-steroidal anti-inflammatory drugs (NSAIDs), or corticosteroids, if necessary. The so-called disease modifying anti-rheumatic drugs do not influence the inflammation or consequently, the pain directly, but rather through mechanisms before the local joint process some of which are not exactly known. In later stages of the progressive joint degeneration the NSAIDs only have a limited effect regarding the inhibition of inflammation. In osteoarthrosis, in which the pain is caused by a secondary inflammation and increasingly by capsular, muscular and tendon involvement, the pain is only treated by NSAIDs in active inflammatory stages; otherwise, the treatment is physical activity and medication. In degenerative and static disorders of the spine the pain is caused predominantly by muscular bracing. Therefore, physical and especially gymnastic therapy play a major role. Whether muscle relaxants have an effect on muscle bracing is doubtful. If there is pressure on the ligaments and, in cases of vertebral dislocation with overstraining of the vertebral joints, therapy with local injections is indicated. The pain in osteoporosis is also predominantly muscular and must be treated accordingly. Above all, high doses of calcium and calcitonin are effective analgesics. Moreover, fluoride also acts as an analgesic once the osteoporosis has stabilized. In most cases fibromyalgia, which is mostly of a psychosomatic nature, cannot be influenced by medical therapy. Instead repeated attempts at treatment help to make the affliction chronic with neurotic fixation. Also, as a rule, myotonolytic and tranquilizing substances are not effective.

Comparative tolerability of treatments for juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) includes several forms of chronic arthritis in children. Treatments are chosen according to the type and severity of the disease. Nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids remain the mainstays of therapy. Traditional slower acting anti-rheumatic drugs, such as gold therapy, penicillamine, sulfasalazine, tiopronin and hydroxychloroquine, are usually poorly active in children. In addition, adverse effects are common, including severe macrophage activation syndrome with gold therapy or sulfasalazine. Low dose, once weekly methotrexate has emerged as the therapeutic agent of choice for children who fail to respond adequately to the administration of an NSAID, especially in those with the extended oligoarticular subtype of the disease. Other immunosuppressive agents, such as cyclosporin, are sometimes combined with methotrexate. In recent years, novel treatments have been developed. Autologous hematopoietic stem cell transplantation is effective in a number of children with severe JIA, whose disease has been refractory to conventional therapy. However, only short term follow-up data are currently available for this novel therapy. In addition, severe infections complicated by macrophage activation syndrome and death have been reported. Finally, anti-tumour necrosis factor-alpha therapy has shown efficacy in more than two-thirds of children with JIA and polyarthritis, and other cytokine inhibitors may be soon available.

Use of Theraflex-TMJ topical cream for the treatment of temporomandibular joint and muscle pain

This randomized, double-blind study was designed to evaluate the effectiveness of the topical cream Theraflex-TMJ (NaBob/Rx, San Mateo, CA) in patients with masseter muscle pain and temporomandibular joint (TMJ) pain. Fifty-two subjects (5 males and 47 females) were instructed to apply a cream over the afflicted masseter muscle(s) or over the jaw joint(s) twice daily for two weeks. Theraflex-TMJ cream was used by the experimental group, while a placebo cream was used by the control group. The means of pain ratings were calculated prior to the application of the cream (baseline), after ten days of tx (period 1), and 15 days of tx (period 2) days of treatment and five days after stopping the treatment (follow-up). There was a significant decrease in reported pain levels from baseline in the experimental group for period 1 (p < 0.01), period 2 (p < 0.001), and follow-up (p < 0.01). For the control group, no significant differences were found between the different time periods (p > 0.05). There was evidence of minor side effects such as skin irritation and/or burning on the site of the application in two subjects in the experimental as well as two subjects in the control groups. The data strongly suggest that Theraflex-TMJ topical cream is safe and effective for reducing pain in the masseter muscle and the temporomandibular joint.

Clostridium difficile toxin A induces the release of neutrophil chemotactic factors from rat peritoneal macrophages: role of interleukin-1beta, tumor necrosis factor alpha, and leukotrienes

Clostridium difficile produces a potent enterotoxin and cytotoxin, toxins A and B, respectively, which appear to be responsible for pseudomenbranous colitis and antibiotic-associated diarrhea. In the present study we explored the neutrophil migration evoked by toxin A in the peritoneal cavities and subcutaneous air pouches of rats and examined the role of macrophages and their inflammatory mediators in this process. Toxin A causes a significant dose-dependent neutrophil influx into the peritoneal cavity, with a maximal response at 0.1 microg/ml and at 4 h. The depletion of macrophages by peritoneal washing prevents the toxin A-induced neutrophil migration into the peritoneal cavity. In contrast, an increase in macrophages induced by peritoneal injection of thioglycolate amplifies this toxin effect on neutrophil migration. Furthermore, the injection of supernatants from toxin A-stimulated macrophages into the rat peritoneal cavity causes significant neutrophil migration. Pretreatment of rats with BWA4C, nordihydroguaiaretic acid, mepacrine, or dexamethasone inhibits the neutrophil migration evoked by toxin A in the peritoneal cavities. However, pretreatment with the cyclooxygenase inhibitor indomethacin or the platelet-activating factor antagonist BN52021 fails to alter toxin A-induced neutrophil migration. Toxin A was also injected into air pouches of normal rats or rats pretreated with anti-interleukin-1beta (anti-IL-1beta) or anti-tumor necrosis factor alpha (anti-TNF-alpha) antibodies. Anti-TNF-alpha or anti-IL-1beta antibodies significantly reduce the neutrophil migration induced by toxin A. These data suggest that neutrophil migration evoked by toxin A is in part dependent on macrophage-derived cytokines, such as TNF-alpha and IL-1beta, and leukotrienes. These mediators may help to explain the intense inflammatory colitis caused by C. dificile toxin A in an experimental animal model of this disease.

Pharmacokinetic behaviour in polymorphonuclear leucocytes of N,N-dimethylcarbamoylmethyl alpha,2-dimethyl-5H-[1]benzopyrano[2,3-b]- pyridine-7-acetate (Y-23023), a new prodrug type of anti-inflammatory agent, and indomethacin after oral administrations in rats

N,N-Dimethylcarbamoylmethyl alpha,2-dimethyl-5H-[1]- benzopyrano[2,3-b]pyridine-7-acetate (Y-23023) is a prodrug developed as a new non-steroidal anti-inflammatory drug (NSAID). Y-23023 is rapidly hydrolysed to an active metabolite, alpha,2-dimethyl-5H-[1]benzopyrano[2,3-b]pyridine-7-acetic acid (M1) following its absorption and then exhibits a strong anti-inflammatory activity. We have examined the pharmacokinetic behaviour in polymorphonuclear leucocytes (PMNs) of M1 and of indomethacin after oral administration to rats of Y-23023 and indomethacin, respectively. Y-23023 was rapidly absorbed, producing a mean Cmax (1.13 micrograms mL-1) of M1 after 1 h in plasma. Indomethacin was less rapidly absorbed, producing a mean Cmax (3.38 micrograms mL-1) after 3 h in plasma. The mean AUC of M1 and indomethacin in plasma were 5.45 micrograms h mL-1 and 22.49 micrograms h mL-1, respectively. The mean tmax, Cmax and AUC of M1 in PMNs were 1 h, 11.1 ng (41 pmol)/10(8) cells and 58.6 ng (164 pmol) h/10(8) cells, respectively. The same parameters for indomethacin in the PMNs were 3 h, 15.4 ng (57 pmol)/10(8) cells and 95.2 ng (266 pmol) h/10(8) cells, respectively. The PMNs/plasma ratio of M1 was about 2.8 times that of indomethacin. These results indicate that the association of M1, an active metabolite of Y-23023, from blood to the PMNs is greater than that of indomethacin.

Nabumetone: a "nonacidic" nonsteroidal antiinflammatory drug

OBJECTIVE

To review the pharmacology, pharmacokinetic disposition, dosage recommendations, adverse effects, drug interactions, and efficacy of nabumetone in patients with selected rheumatic disorders and soft-tissue injuries.

DATA SOURCES

Data from scientific literature were extracted, evaluated, and summarized for presentation. A MEDLINE search was conducted using the following indexing terms: antiinflammatory agents, nonsteroidal, nabumetone, rheumatoid arthritis (RA), and osteoarthritis (OA). Studies evaluating nabumetone reported in articles, abstracts, or proceedings involving human subjects were considered for inclusion.

STUDY SELECTION

Special consideration was given to clinical studies using double-blind, randomized, parallel, controlled designs. Studies comparing the effectiveness and safety of nabumetone with placebo and other nonsteroidal antiinflammatory drugs (NSAIDs) were included.

DATA EXTRACTION

Data from human studies published in the English language were evaluated. Trials were assessed according to study design, sample size, and description of outcomes.

DATA SYNTHESIS

Nabumetone is a nonacidic prodrug that is metabolized to an active nonsteroidal antiinflammatory moiety, 6-methoxy-2-naphthylacetic acid (6-MNA). 6-MNA is a structural analog of naproxen. Like naproxen and other NSAIDs, 6-MNA possesses analgesic, antipyretic, and antiinflammatory activity, 6-MNA has a prolonged elimination half-life, ranging from 17 to 74 hours, which allows for once-daily dosing. The efficacy of nabumetone for treating symptoms of RA and OA has been established in controlled clinical trials. Nabumetone also has been studied in ankylosing spondylitis and soft-tissue injuries. Adverse effects associated with nabumetone are similar to those associated with other NSAIDs. Gastrointestinal reactions occur most frequently in the form of abdominal pain or indigestion, nausea, or vomiting. Central nervous system adverse effects occur less frequently, and are followed in order of occurrence by rashes.

CONCLUSIONS

Nabumetone is a prodrug metabolized to an active metabolite structurally related to naproxen. Studies have demonstrated the efficacy of nabumetone, but no advantages over the many other NSAIDs now available.

In vitro effects of methotrexate on peripheral blood monocytes: modulation by folinic acid and S-adenosylmethionine

The mechanism of action of low dose methotrexate in rheumatoid arthritis has not been established. It has been shown to have an anti-inflammatory effect and to inhibit neutrophil chemotaxis, but the effect on monocytes has not been widely studied. Normal donor peripheral blood monocytes were incubated with methotrexate in vitro and their superoxide production, chemotaxis, and phagocytosis subsequently assessed. Additionally, the influence of different culture media, and of folinic acid, and the methyl donor S-adenosylmethionine, and spermidine on the methotrexate mediated effects were evaluated. It was found that methotrexate in low concentrations inhibited in vitro monocyte chemotaxis and superoxide production but only after prolonged incubation. This inhibition was augmented by incubation in medium containing a low methionine concentration and was abolished by folinic acid and S-adenosylmethionine, suggesting that methotrexate may interfere with specific methylation reactions.

Non-steroidal anti-inflammatory drugs: effects on a GTP binding protein within the neutrophil plasma membrane

Sodium salicylate and other non-steroidal anti-inflammatory drugs (NSAIDs) inhibit neutrophil functions via unknown mechanisms. To examine their site of action in the neutrophil we have studied discrete events within the plasma membrane which depend upon the normal function of a GTP binding protein (G protein). We demonstrated that sodium salicylate and piroxicam inhibit neutrophil activation in response to stimuli which require signal transduction via a G protein (e.g. formyl-methionine-leucine-phenylalanine) but have no effect on stimuli which do not (e.g. phorbol myristate acetate, ionomycin). NSAIDs blocked the ADP-ribosylation of the pertussis toxin substrate in human neutrophils. This effect was associated with the capacity of NSAIDs to block pertussis toxin-dependent inhibition of neutrophil functions. Finally, NSAIDs inhibited the binding of GTP gamma S, a stable analog of GTP, to purified neutrophil membrane preparations. The data indicate that salicylate and other NSAIDs interact with a G protein in the neutrophil plasmalemma and thereby uncouple post-receptor signaling events.

A skin suction blister model in hairless rats: application to the study of anti-inflammatory and immunomodulatory drugs

A suction blister model was developed in the hairless rat, in order to study the effects of various agents on the migration of polymorphonuclear leukocytes (PMN). A standardized abrasion, a suction blister, was formed by applying negative pressure to the skin and then separating the epidermis from the dermis. A migration chamber containing serum as the chemoattractant was placed over the wound. After 6 h of migration, the cells in the chamber were harvested, counted and identified. We evaluated PMN migration after treating the animals with active compounds: niflumic acid, and anti-inflammatory drug, and RU 41740, an immunomodulator. This in vivo model provided reproducible data and could be used to study further the functional properties of PMN. In addition, because this assay can also be used in man, a drug found to be effective in the animal system could then be tested for its activity in man.

Effects of non-steroidal anti-inflammatory drugs on canine neutrophil chemotaxis

Non-steroidal anti-inflammatory drugs exhibit differences in their ability to suppress polymorphonuclear leucocyte (PMN) functions in different species. The present study investigated the in-vitro and ex-vivo effects of phenylbutazone and flunixin on leukotriene-B4-directed migration of canine PMN. Furthermore, in-vitro comparison was made to indomethacin and the 5-lipoxygenase inhibitor, nordihydroguaiaretic acid (NDGA). In vitro, flunixin and NDGA were the most potent inhibitors, with IC50S of 13 and 7 mumol/l, respectively. Phenylbutazone had an IC50 of 42 mumol/l whereas indomethacin did not achieve 50% inhibition at concentrations less than 100 mumol/l. Ex vivo, flunixin almost completely abolished the LTB4 response at 1 h, and still possessed significant inhibitory activity 24 h after a dosage of 1 mg/kg i.v. Phenylbutazone was less active ex vivo but did suppress chemotaxis by 23% (P less than 0.05) at 1 h following an i.v. dose of 20 mg/kg. It is suggested that part of the anti-inflammatory action of flunixin in dogs may be attributed to inhibition of PMN recruitment.

Nonsteroidal antiinflammatory drugs exert differential effects on neutrophil function and plasma membrane viscosity. Studies in human neutrophils and liposomes

Nonsteroidal antiinflammatory drugs (NSAIDs) inhibit neutrophil functions via mechanisms separate from their capacity to inhibit prostaglandin synthesis. We have studied discrete events in the process of signal transduction: NSAIDs but not a related analgesic drug (acetaminophen), inhibited aggregation in response to the chemoattractants f-Met-Leu-Phe (FMLP), leukotriene B4, and C5a. NSAIDs, but not acetaminophen, inhibited binding of radiolabeled FMLP to purified neutrophil membranes. Gpp(NH)p, a GTPase insensitive analog of GTP, also inhibited the binding of FMLP but, paradoxically, enhanced superoxide anion generation and lysozyme release. The inhibition of ligand binding by NSAIDs did not correlate with their capacity to inhibit FMLP-induced increments in diacylglycerol (DG): piroxicam, but not salicylate effectively inhibited appearance of label ([3H]arachidonate, [14C]glycerol) in DG. Finally, NSAIDs exerted differential effects on the viscosity of neutrophil plasma membranes and multilamellar vesicles (liposomes): membrane viscosity was increased by piroxicam and indomethacin, decreased by salicylate, and unaffected by acetaminophen. Thus, the different effects of NSAIDs on discrete pathways are not due to their shared capacity to reduce ligand binding but rather to a capacity to uncouple postreceptor signaling events that depend upon the state of membrane fluidity.

Pain associated with juvenile rheumatoid arthritis

Despite a comprehensive approach to the treatment of JRA patients, pain remains a largely underdeveloped area of research and an undertreated clinical problem. Pain is a highly prevalent condition in JRA patients, one that in adults has been shown to be highly predictive of current medication usage and future disability. This recurrent or chronic pain syndrome is currently treated primarily with nonsteroidal anti-inflammatory drugs, but inclusion of pain management specialists on the interdisciplinary team will allow for greater use of nonpharmacologic means of pain management.

Eicosanoids and rheumatology: inflammatory and vascular aspects

Eicosanoids are not only involved in inflammation but also are important in the maintenance of blood vessel tone and blood flow. This may be relevant in the rheumatological disorders of vasculitis and RS. Although little work has been carried out in vasculitis, the beneficial effects of the natural and synthetic antiplatelet vasodilator PGs in RS are well documented. Less well tested has been the effects of manipulation of AA metabolism. It should be remembered however that many patients with Raynaud's Phenomenon do not have an associated rheumatological disorder. Conservative management with vasodilators such as the calcium channel blockers may be very successful (119). At the present time PG treatment should be reserved for patients with severe RS, particularly those whose Raynaud's is complicated by digital ulceration.

Arachidonic acid products and the thoracic accumulation of neutrophils and platelets following i.v. antigen challenge of sensitised guinea-pig

The 5-lipoxygenase inhibitors, AA861 and phenidone, have been shown to inhibit the formation and release of leukotrienes C4, D4 and B4 from isolated perfused sensitised guinea pigs lungs when challenged through either the pulmonary system or the airways. The same drugs inhibit the thoracic neutrophil, but not platelet, accumulation observed following i.v. antigen challenge of sensitised guinea pigs. Indomethacin, a cyclooxygenase inhibitor, at doses which inhibited an arachidonic acid-induced thoracic platelet accumulation, had no effect on the platelet response following antigen challenge. Indomethacin did affect, however, the neutrophil response to antigen challenge presumably through mechanisms unrelated to cyclooxygenase inhibition. These observations suggest a role for lipoxygenase products, possibly LTB4, but not cyclooxygenase products in the neutrophil response to i.v. antigen challenge.

Cutaneous inflammation: effects of hydroxy acids and eicosanoid pathway inhibitors on vascular permeability

Four metabolic products of arachidonic acid lipoxygenation, 5-hydroxyeicosatetraenoate (5-HETE), 12-HETE, 15-HETE, 5(S),12(S)-DiHETE, were injected intradermally into depilated dorsae of albino guinea pigs. The presence of intravenously injected 125I-bovine serum albumin (10uCi/kg) in 13-mm punch biopsy specimens served as a marker for altered vascular response; histologic changes were evaluated at 6 and 24 h after the injection in 1-micron-thick sections. Thirty minutes after the injections of 15 nanomoles and 60 nanomoles of 5-HETE, the ratios of radioactivity in HETE-injected to that in buffer-injected sites were 1.35 +/- 0.06 (mean +/- SE) and 2.80 +/- 0.27, respectively. Corresponding effects of 15-HETE were 1.39 +/- 0.17 and 1.63 +/- 0.21, respectively. Values for 60 nanomoles of 12-HETE and 5,12-DiHETE were intermediate in comparison with the above eicosanoids. The most notable histologic changes were a neutrophilic infiltrate induced by 12-HETE at 6 and 24 h, and neutrophilic and eosinophilic infiltrates in response to 5,12-DiHETE injection at 6 and 24 h. Effects of topically applied eicosanoid pathway inhibitors were also evaluated, using intradermally injected sodium arachidonate (AA) as agonist. Three mixed cyclooxygenase/lipoxygenase inhibitors, BW755C, phenidone, and nordihydroguaiaretic acid, suppressed vascular response by 9%, 9%, and 6% for 150 nmol of AA, and by 9%, 13%, and 12% for 300 nmol of AA, respectively. The cyclooxygenase inhibitor, indomethacin, induced suppressions of 39% for 150 nmol AA and 22% for 300 nmol AA, respectively. These data demonstrate that metabolites of both cyclooxygenase and lipoxygenase eicosanoid pathways are involved in alteration in vascular response accompanying cutaneous inflammation.

Anti-arthritic activity of boswellic acids in bovine serum albumin (BSA)-induced arthritis

The effect of boswellic acids on bovine serum albumin (BSA)-induced arthritis in rabbits was studied. Oral administration of boswellic acids (25, 50 and 100 mg/kg/day) significantly reduced the population of leucocytes in a BSA-injected knee and changed the electrophoretic pattern of the synovial fluid proteins. The local injection of boswellic acids (5, 10 and 20 mg) into the knee 15 min prior to BSA challenge also significantly reduced the infiltration of leucocytes into the knee joint, reduced the infiltration of leucocytes into the pleural cavity and inhibited the migration of PMN in vitro. The leucocyte-inhibitory activity of boswellic acids was not due to its cytotoxic effect. The boswellic acids did not show any detergent or surfactant properties.

Effect of salai guggal ex-Boswellia serrata on cellular and humoral immune responses and leucocyte migration

Effect of alcoholic extract of salai guggal (AESG) was studied on cellular and humoral immune responses in mice and leucocyte migration in rats. Oral administration of AESG strongly inhibited the antibody production and cellular responses to sheep red blood cells in mice. It inhibited the infiltration of polymorphonuclear leucocytes and reduced the volume of pleural exudate in carrageenan induced pleurisy in rats. It showed no cytotoxic effect.

Inhibition by nonsteroidal anti-inflammatory drugs of superoxide production and granule enzyme release by polymorphonuclear leukocytes stimulated with immune complexes or formyl-methionyl-leucyl-phenylalanine

The effects of nonsteroidal anti-inflammatory agents on superoxide production and granule enzyme release by human polymorphonuclear leukocytes stimulated with either formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe] or immune complexes were investigated. Cytochrome c reduction and the release of lysozyme, beta-glucuronidase, myeloperoxidase and gelatinase were measured. Auranofin, phenylbutazone, sulfasalazine and the phospholipase A2 inhibitor, 4-bromophenacyl bromide, strongly inhibited these responses in fMet-Leu-Phe stimulated cells, at concentrations below 50 microM. Indomethacin, piroxicam, mefenamic acid, primaquine and quinacrine at 50-250 microM were inhibitory. Up to 1 mM ibuprofen and chloroquine inhibited superoxide production but had little effect on degranulation. With cells stimulated by IgG aggregates (immune complexes), up to 1 mM ibuprofen, mefenamic acid and piroxicam did not inhibit either response. Indomethacin, phenylbutazone, sulfasalazine and primaquine inhibited, but considerably higher concentrations were required than with fMet-Leu-Phe. Quinacrine inhibited superoxide production equally well with both stimuli but inhibited enzyme release only with fMet-Leu-Phe. Only auranofin, 4-bromophenacyl bromide, and the weakly effective chloroquine exerted approximately the same effect with both stimuli. D-Penicillamine did not affect enzyme release with either stimulus and interfered in the superoxide assay. Gelatinase release induced by fMet-Leu-Phe was affected to the same extent, or slightly more, than release of the other granule enzymes. With immune complexes, there was only modest inhibition of gelatinase release by any of the drugs at 250-1000 microM. Our results reinforce previous observations that many anti-inflammatory drugs affect neutrophil functions, but their effects vary with stimulus. The relative insensitivity of immune complex-induced responses to most of the drugs must be taken into account when considering their mode of action.

A review of mechanism of action of aspirin and its potential as an immunomodulating agent

The basic aspects of PG immune function interactions are presented and discussed herein. Specifically, the findings of many of the studies summarized suggest the possibility that pharmacologic actions of aspirin may play a role in enhancing the immune response to viral infections. Mechanisms proposed for ASA include: PG inhibition via the cyclooxygenase pathway, an interaction with cyclic nucleotides, altered cellular interactions with PG's, altered leukocyte migration, activation of complement components, stimulation of monocytopoiesis, and induction of interferon. Since dual effects for ASA have been observed for several of these mechanisms, it is clear that its role in modulating the immune response to viral infections is very complex. This delineation of a role for ASA, that would seem to constitute a defense against viral infections leads to an area worthy of study and surveillance.

Salvage of ischemic rabbit ear by BW-755C and steroids, but not by indomethacin

The effects of anti-inflammatory steroids and BW-755C (both of which inhibit the formation of prostaglandins and leukotrienes) were studied in ischemia-induced edema and necrosis of the rabbit ear utilizing an occlusion reperfusion model. The results were compared with cyclooxygenase inhibitors which selectively block the synthesis of prostaglandins without affecting leukotriene production. Significant inhibition of the progression of necrosis was observed with both methyl prednisolone and BW-755C. The cyclooxygenase inhibitors, naproxen and low-dose indomethacin had no effect on the progression of ear necrosis. By contrast, high-dose indomethacin significantly inhibited edema but accelerated the progression of necrosis.

A comparison of air pouch, sponge and pleurisy models of acute carrageenan inflammation in the rat

A comparative assessment of the time course of changes in three models of acute carrageenan-induced inflammation, the six-day air pouch, polyester sponge and pleurisy models, was obtained by measuring exudate volume, leucocyte numbers, PGE2 concentrations and lactate dehydrogenase activity at 2, 6 and 24 h. The greatest increases in exudate volume, leucocyte numbers and PGE2 concentration and the smallest rise in protein occurred in the air pouch model. Increases in lactate dehydrogenase were greatest in the sponge and least in the pleural exudate, indicating that the least cell damage occurred in the pleurisy model. PGE2 was not detectable in most pleural exudate samples. The actions of two steroids, betamethasone and dexamethasome, at two dose levels, 80 and 160 micrograms/kg, were assessed in each model. Overall, the six-day air pouch was found to be most satisfactory and most sensitive for assessing the actions of the steroids. The sponge model was either less sensitive or gave inconsistent responses, for the variables measured, than the cavity models of inflammation. Since the six-day air pouch has previously been shown to resemble synovium, our findings indicate that it is likely to be superior to the other two models as a model of joint inflammation.

Leukocyte recruitment in the subcutaneous sponge implant model of acute inflammation in the rat is not mediated by leukotriene B1

The subcutaneous sponge implant model of acute inflammation in the rat has been evaluated as a suitable test system for evaluating the potential anti-inflammatory efficacy of 5-lipoxygenase inhibitors. The inflammatory parameters measured were exudate volume and leukocyte recruitment. Specific radioimmunoassays were used to measure (1) 5-lipoxygenase (LPO) and cyclo-oxygenase (CO) activity in exudate leukocytes stimulated ex vivo with A23187, and (2) the LTB4 and PGE2 content of inflammatory exudate. The NSAIDs flurbiprofen and indomethacin inhibited cell recruitment, exudate volume and CO activity with ED50S of approximately 1 mg per kg p.o. but failed to inhibit LPO activity at 10 mg per kg p.o. Nafazatrom (Bayer 6575), quercetin and NDGA, which inhibit LPO activity in vitro, were inactive against all parameters when dosed at 100 mg per kg p.o. The "mixed inhibitors" BW755C and phenidone were approximately equipotent inhibitors of LPO activity but BW755C was 10 times more potent than phenidone against CO activity. BW755C was also greater than 10 times more potent at inhibiting cell recruitment and exudate volume than phenidone suggesting that the anti-inflammatory efficacy of the mixed inhibitors reflect their potency against CO rather than LPO activity. Time course studies demonstrated that the inhibitor effects of BW755C and phenidone on leukocyte recruitment reflected a reduction in the PGE2 but not the LTB4 content of the inflammatory exudate. Polyester sponges soaked in high concentrations of LTB4 caused only a modest (2-fold) increase in leukocyte recruitment whilst physiological levels were inactive. The results taken together suggest that CO products make a major contribution to leukocyte recruitment in this model whilst the LPO product LTB4 has little role. This model therefore is of little value for evaluating the anti-inflammatory efficacy of 5-lipoxygenase inhibitors. Moreover, the rat would appear to be unsuitable for evaluating the role of LTB4 in acute inflammation.

Modes of action of aspirin-like drugs

Current dogma holds that nonsteroidal anti-inflammatory drugs (NSAIDs) act by inhibition of the synthesis and release of prostaglandins. However, NSAIDs also inhibit the activation of neutrophils, which provoke inflammation by releasing products other than prostaglandins. We now report that NSAIDs (e.g., indomethacin, piroxicam) inhibit activation of neutrophils by inflammatory stimuli, such as C5-derived peptides and leukotriene B4, even when cyclooxygenase products generated in suspensions of stimulated neutrophils (prostaglandin E and thromboxanes) are present. Sodium salicylate (3 mM) greatly inhibited aggregation of neutrophils but had no effect on aggregation of platelets or production of thromboxane induced by arachidonate. Sodium salicylate and other NSAIDs also inhibit calcium movements (45Ca uptake, changes in fluorescence of chlortetracycline and quin-2). Aspirin, sodium salicylate, indomethacin, and piroxicam also enhanced the poststimulation increase in intracellular cyclic AMP. NSAIDs therefore inhibit early steps in neutrophil activation as reflected by their capacity to inhibit movements of Ca and to enhance intracellular levels of cyclic AMP.

Models for evaluating the anti-inflammatory effects of inhibitors of arachidonic acid metabolism

Inhibitors of arachidonic acid metabolism were characterized by their ability to modulate slow reacting substance (SRS) and prostaglandin E2 (PGE2) release from stimulated mouse peritoneal macrophages in-vitro. Differential effects of cyclo-oxygenase (CO) and lipoxygenase (LO) enzyme inhibitors and compounds which inhibit both enzymes were demonstrated using several animal models of inflammation. Carrageenan-impregnated sponges implanted subcutaneously in rats and immune-complexes injected intraperitoneally in mice produced inflammatory responses characterized respectively by polymorphonuclear (PMN) cell infiltration and by increased vascular permeability. Dual CO/LO inhibitors (eg. BW 755c and timegadine) were capable of suppressing both parameters and reduced SRS and PGE2 formation in-vivo. In contrast, selective CO inhibitors (e.g. indomethacin, naproxen and R-830) were less active against permeability, and potentiated SRS release. Although selective CO inhibitors reduced PMN migration, this occurred at doses which exceeded those required for inhibition of PGE2. Compounds possessing LO inhibitory activity suppressed the cellular component of an Arthus type reaction in the rat pleural cavity, but were less active than selective CO inhibitors against carrageenan-induced paw oedema in rats.

In vivo modulation of leukotaxis by non-steroidal anti-inflammatory drugs

Since non-steroidal anti-inflammatory drugs (NSAIDs) are widely used for inhibition of inflammation, an in vivo assay for leukotaxis would be of use in comparing the biological activity effects of the agents. Here, the effects of 4 different NSAIDs on in vivo leukocyte accumulation was determined by quantitating N-formyl-methionyl-leucylphenylalanine induced leukotaxis in the rabbit anterior eye chamber. New Zealand white female rabbits were treated for three days with the following regimens: ibuprofen or aspirin, 0.1, 1.0, 10.0 or 100.0 mg/kg/day, indomethacin or flurbiprofen, 0.01, 0.1, 1.0, or 10.0 mg/kg/day. Indomethacin and flurbiprofen significantly reduced leukotaxis in a dose of 10.0 mg/kg/day. Aspirin was associated with a weak inhibition of leukotaxis. Ibuprofen had biphasic effects, 1.0 mg/kg/day potentiated and 10 mg/kg/day inhibited leukotaxis, whereas leukocyte accumulation was uneffected by a high dose (100.0 mg/kg/day). These results suggest that modulation of leukotaxis by NSAIDs may reflect a differential dose-response sensitivity of lipoxygenase and cycloxygenase pathways.

Modulation of leukotaxis by ibuprofen. A quantitative determination in vivo

The purpose of this study was to evaluate the rabbit anterior eye chamber as a quantitative measure of leukotaxis using 51Cr-labeled homologous leukocytes and then to determine the effects of ibuprofen on N-formyl-methionyl-leucyl-phenylalanine (FMLP) -induced leukotaxis. Leukocyte accumulation was assessed at various intervals (0-24 h) after instillation of FMLP (10(-4) M, 40 microliters) and at various doses (FMLP 10(-6)-10(-4) M). New Zealand white rabbits (2.6-3.0 kg) were treated with ibuprofen for three days with the following regimens: 8.0, 17.5, 35.0, 70.0 mg/kg/ day. Leukocyte quantitation was determined using a direct cell count and recovery of 51Cr-labeled leukocytes from anterior eye chamber aspirations 3 h after their injection into the systemic circulation. FMLP induced a dose-dependent accumulation of leukocytes. Leukocyte influx into the anterior eye chamber increased between 2 and 4 h after FMLP instillation, peaking between 4 and 6 h, then resolving after 8 h. Ibuprofen inhibited leukocyte accumulation into the anterior eye chamber in a dose dependent fashion with a maximum (90.0 +/- 1.4%, X +/- SEM) inhibition with 70 mg/kg/day and an ID50 of 8 mg/kg/day. In conclusion, the anterior eye chamber FMLP-stimulated leukotaxis assay is useful to evaluate the role of pharmacologic agents. Here, ibuprofen was found to inhibit leukotaxis in a dose-dependent manner.

Copper and inflammation--a possible rationale for the pharmacological manipulation of inflammatory disorders

Acute and chronic inflammations are characterized, among other features, by changes in the metabolism of copper and by a widespread responsiveness to the therapy with copper-containing molecules. The exact map of inflammation-induced copper movements as well as the role played by the metal in the pathogenesis of inflammatory disorders are, however, far from being clear, and this is especially true in the case of chronic processes. Nevertheless the present knowledge suggests that the "copper approach' may provide a new way for coping with the problem of anti-inflammatory/anti-arthritic therapies. The administration of exogenous copper, and the in vivo manipulation of the endogenous metal levels are proposed as two possible therapeutic strategies, not necessarily mutually exclusive. For a better understanding of the value of such an approach, further research work is needed, especially to attain a more detailed know-how on the involved chemical forms, distribution and functions of copper in both normal as well as inflamed organisms.

Directional movement of cells in vivo and in vitro under the influence of 5-lipoxygenase inhibitors

Five inhibitors of 5-lipoxygenase activity [phenidone, nordihydroguaiaretic acid (NDGA), BW755c, nafazatrom and the methyl ester of caffeic acid] have been compared with the cyclo-oxygenase inhibitor indomethacin as inhibitors of aggregation and chemotaxis by guinea-pig polymorphonuclear leukocytes. The results suggest that neither 5-lipoxygenase nor cyclo-oxygenase products are of significance in these in vitro assays. However, all of these compounds, with the exception of BW755c, significantly inhibited cell accumulation in an acute inflammatory model. These results cast doubt on the central importance of any individual arachidonic acid metabolite in the development of inflammation in vivo.

Comparison of anti-inflammatory compounds in the carrageenan induced paw edema model and the reversed passive Arthus model utilizing the same animal

In order to better define antiinflammatory activity in new agents, a test was devised utilizing both carrageenan induced paw edema and the reversed passive Arthus reaction in the same animal. The model of carrageenan induced rat paw edema is a standard laboratory assay used to predict classical "aspirin-like" antiinflammatory molecules. The reversed passive cutaneous Arthus reaction involves precipitating antigen-antibody complexes, complement and infiltrating polymorphonuclear leukocytes (PMN's) and can be used to identify agents that affect one or more of these factors specifically. Antiinflammatory compounds were given orally one hour prior to the administration of carrageenan and goat anti-rat serum. Comparisons were made between several non-steroidal compounds and the steroid hydrocortisone. All of the compounds tested gave good carrageenan activity, but only hydrocortisone produced significant Arthus lesion inhibition in this assay.

The biology, pathophysiology and control of eicosanoids in inflammation

The involvement in inflammatory conditions of those cyclo-oxygenase and lipoxygenase derivatives of arachidonic acid (5,8,11,14-eicosatetraenoic acid), which are known as the eicosanoids, is reviewed in the light of recent studies. Although it is now generally recognized that cyclo-oxygenase products are fundamental to the inflammatory process as chemical mediators, and that inhibition of the cyclo-oxygenase enzyme pathway explains the mode of action of most non-steroidal anti-inflammatory drugs (NSAIDs) commonly prescribed in veterinary practice, evidence for the involvement of lipoxygenase products of arachidonate metabolism in inflammation is increasing. The leukotrienes (LTs) are 5-lipoxygenase-derived eicosanoids which have been shown to be leucotactic and involved in anaphylactic and hypersensitivity reactions. Leucocytes, drawn to sites of injury by chemotaxis, themselves liberate pro-inflammatory eicosanoids which perpetuate the response and may aggravate the clinical condition. At therapeutic dose rates, most NSAIDs have no effect on the biosynthesis of LTs, whereas corticosteroids, by inhibiting the release of arachidonic acid, may prevent the formation of both cyclo-oxygenase and lipoxygenase products. However, because of the undesirable side-effects of steroids, the clinical use of these agents in treating inflammatory conditions is sometimes limited. Novel non-steroid inhibitors of cyclo-oxygenase and lipoxygenase enzyme pathways could offer more effective and safer control of inflammation in animals.

Therapeutic reduction of ongoing carrageenin-induced inflammation by lipoxygenase, but not cyclooxygenase inhibitors

A variety of steroidal and nonsteroidal antiinflammatory agents (NSAs) were compared for their effectiveness against a developing acute inflammatory reaction. Only BW 755C [3-amino-1-(m-trifluoromethyl)-phenyl-2-pyrazole] was immediately effective when administered 2 h after carrageenin, as the 3-h swelling was significantly reduced. Dexamethasone, a steroidal antiinflammatory agent, produced a delayed reduction. When administered at 2 h postcarrageenin, there was no effect at 3 h; but at 6 h, dexamethasone significantly reduced the swelling. In contrast, neither of the classic NSAs, aspirin or indomethacin, were effective when administered after the carrageenin. The results demonstrating a postcarrageenin effectiveness by BW 755C and dexamethasone are discussed as a possible reflection of an action on the lipoxygenase pathways of the arachidonic cascade that is not shared by the classic NSA.

Ibuprofen in the prevention of experimentally induced postoperative adhesions

Using a five-dose 70 mg/kg regimen, of ibuprofen significantly reduced both overall adhesion formation and the severity of adhesions when given to rabbits in the immediate postoperative period. This reduction was apparently time- and dose-related, as animals given smaller doses of ibuprofen at subsequent intervals had a tendency toward more adhesions and also more severe adhesions. A positive correlation was found between the severity of adhesions and the formation of new glycosaminoglycans and collagens.