Non-steroidal anti-inflammatory drugs, Helicobacter pylori and bleeding gastric ulcer

BACKGROUND: Helicobacter pylori infection and NSAID usage are considered to be independent risk factors for gastric ulcer (GU). Whether they interact to influence the risk of bleeding in GU is unclear. AIM: To determine the prevalence of H. pylori infection and NSAID ingestion in a group of patients with GU and determine their roles in bleeding and non-bleeding GU. METHODS AND RESULTS: From January 1993 to June 1996, a total of 217 GU patients (150 male, 67 female, median age 61 years, range 26-94) were eligible for the study. Eighty-five per cent were H. pylori-positive and 15% were H. pylori-negative. NSAID usage within 4 weeks prior to endoscopy was present in 30%, more in the H. pylori-negative than H. pylori-positive patients (59% vs. 25% P = 0.0002). Aspirin was most commonly used (43%). One hundred patients bled from GU (69 male, 31 female, mean age 67 years, range 26-94) and 117 did not (81 male, 36 female, mean age 57 years, range 28-86). Univariate logistic regression showed that advanced age (>/= 65 years) and NSAID usage carried an increased risk of bleeding GU (odds ratio 3.4 and 6.8, respectively) while H. pylori infection alone was not associated with additional risk (OR = 0.8). However, when three variables were considered jointly in a multiple logistic regression, the OR associated with H. pylori infection increased to 2.4, suggesting that in the presence of NSAIDs and advanced age, H. pylori also increases the risk of bleeding GU, indicating an interaction between the variables. CONCLUSION: NSAID usage and advanced age are risk factors for bleeding GU, whereas H. pylori infection by itself is not. In the presence of NSAIDs and advanced age, an increased risk of bleeding GU with H. pylori is observed, indicating the possibility of an interaction between these factors.     

Non-steroidal anti-inflammatory drugs in the treatment of migraine

NSAIDs can be used in both the acute and prophylactic treatment of migraine with and without aura. It is a safe therapeutic alternative fore young healthy patients, but should be used with caution in the elderly. NSAIDs do not influence blood pressure and can be used in combination with most other migraine agents. The selective COX-2 inhibitors are an interesting therapeutic possbility for the future.     

Role of carbonyl reducing enzymes in the phase I biotransformation of the non-steroidal anti-inflammatory drug nabumetone in vitro

1.?Nabumetone is a clinically used non-steroidal anti-inflammatory drug, its biotransformation includes major active metabolite 6-methoxy-2-naphtylacetic acid and another three phase I as well as corresponding phase II metabolites which are regarded as inactive. One important biotransformation pathway is carbonyl reduction, which leads to the phase I metabolite, reduced nabumetone.

2.?The aim of this study is the determination of the role of a particular human liver subcellular fraction in the nabumetone reduction and the identification of participating carbonyl reducing enzymes along with their stereospecificities.

3.?Both subcellular fractions take part in the carbonyl reduction of nabumetone and the reduction is at least in vitro the main biotransformation pathway. The activities of eight cytosolic carbonyl reducing enzymes – CBR1, CBR3, AKR1B1, AKR1B10, AKR1C1-4 – toward nabumetone were tested. Except for CBR3, all tested reductases transform nabumetone to its reduced metabolite. AKR1C4 and AKR1C3 have the highest intrinsic clearances.

4.?The stereospecificity of the majority of the tested enzymes is shifted to the production of an (+)-enantiomer of reduced nabumetone; only AKR1C1 and AKR1C4 produce predominantly an (?)-enantiomer. This project provides for the first time evidence that seven specific carbonyl reducing enzymes participate in nabumetone metabolism.     

Photosensitizing properties of 6-methoxy-2-naphthylacetic acid, the major metabolite of the phototoxic non-steroidal anti-inflammatory and analgesic drug nabumetone

The photobiological properties of 6-methoxy-2-naphthylacetic acid (6-MNAA) were studied using a variety of in vitro phototoxicity assays: photohemolysis, photoperoxidation of linoleic acid, photosensitized degradation of histidine and thymine and the Candida phototoxicity test. 6-MNAA was phototoxic in vitro. 6-MNAA reduced nitro blue tetrazolium (NBT) when irradiated with lambda > or = 300 nm in deoxygenated aqueous buffer solution (pH 7.4). NBT can be reduced by reaction with the excited state of 6-MNAA subject to interference with molecular oxygen. The photohemolysis rate was inhibited by the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO), sodium azide (NaN3) and reduced glutathione (GSH). Photoperoxidation of linoleic acid and photosensitized degradation of histidine and thymine were significantly inhibited by sodium azide and reduced glutathione. 6-MNAA was phototoxic to C. albicans, C. lipolytica and C. tropicalis. A mechanism involving singlet oxygen, radicals, and electron transfer reactions is suggested for the observed phototoxicity.     

Non-steroidal anti-inflammatory drug for pulmonary administration: Design and investigation of ketoprofen lysinate fine dry powders

Pulmonary inflammation is an important therapeutic target in cystic fibrosis (CF) patients, aiming to limit and delay the lung damage. The purpose of the present research was to produce respirable engineered particles of ketoprofen lysinate, a non-steroidal anti-inflammatory drug able to fight lung inflammatory status by direct administration to the site of action. Micronized drug powders containing leucine as dispersibility enhancer were prepared by co-spray drying the active compound and the excipient from water or hydro-alcoholic feeds. Microparticles were fully characterized in terms of process yield, particle size distribution, morphology and drug content. The ability of the drug to reach the deepest airways after aerosolization of spray-dried formulations was evaluated by Andersen cascade impactor, using the monodose DPI as device. In order to investigate the behaviour of the drug once in contact with lung fluid, an artificial CF mucus was prepared. Drug permeation properties were evaluated interposing the mucus layer between the drug and a synthetic membrane mounted in Franz-type diffusion cells. Finally, the effect of the engineered particles on vitality of human airway epithelial cells of patients homozygous for ΔF 508 CF (CuFi1) was studied and compared to that of raw active compound. Results indicated that powders engineering changed the diameter and shape of the particles, making them suitable for inhalation. The mucus layer in the donor compartment of vertical diffusion cells slowed down drug dissolution and permeation, leucine having no influence. Cell proliferation studies evidenced that the spray drying process together with the addition of leucine reduced the cytotoxic effect of ketoprofen lysine salt as raw material, making the ketoprofen lysinate DPI a very promising product for the inflammation control in CF patients.     

Plaunotol prevents indomethacin-induced gastric mucosal injury in rats by inhibiting neutrophil activation

BACKGROUND: Activated neutrophils play a critical role in indomethacin-induced gastric mucosal injury. AIM: To investigate the effect of plaunotol, an anti-ulcer agent, on neutrophil activation in vitro and its effect on gastric mucosal injury and gastric accumulation of neutrophils in rats given indomethacin. METHODS: Human monocytes and neutrophils were isolated from the peripheral blood of healthy volunteers. We examined the effect of plaunotol on neutrophil elastase release, production of O2-, intracellular calcium concentration and expression of adhesion molecules CD11b and CD18 in activated neutrophils in vitro. The effect of plaunotol on TNF-alpha production by monocytes stimulated with endotoxin also was investigated in vitro. The effect of plaunotol (100 mg/kg, p.o.) on gastric mucosal injury and neutrophil accumulation was investigated in male Wistar rats given indomethacin (30 mg/kg, p.o.). RESULTS: Plaunotol inhibited the fMLP-induced release of neutrophil elastase from activated neutrophils, as well as the opsonized zymosan-induced production of O2- by neutrophils. Plaunotol significantly inhibited increased levels of intracellular calcium, a second messenger of neutrophil activation, in vitro. The fMLP-induced increases in CD11b and CD18 expression were also inhibited by plaunotol in vitro. Plaunotol inhibited monocytic production of TNF-alpha, a potent activator of neutrophils. Both gastric mucosal injury and gastric neutrophil infiltration in rats given indomethacin were significantly inhibited by the oral administration of plaunotol. CONCLUSIONS: Plaunotol inhibits indomethacin-induced gastric mucosal injury, at least in part by inhibiting neutrophil activation.     

Effect of nabumetone (BRL 14777), a new anti-inflammatory drug, on human platelet reactivity ex vivo: comparison with naproxen

The effect of nabumetone (BRL 14777) on human platelet reactivity ex vivo was compared with that of naproxen at equitherapeutic doses in the same six subjects. Nabumetone had only a weak and equivocal effect on collagen-induced and second phase aggregation in response to adenosine diphosphate and adrenaline. After nabumetone, platelets fully aggregated in response to sodium arachidonate, though approximately twice as much was needed as on control occasions. Sodium arachidonate was unable to elicit a full aggregation response after naproxen. These results suggest that nabumetone may cause less interference with haemostasis than other non-steroidal anti-inflammatory drugs.     

Non-steroidal anti-inflammatory drug (NSAID)-derived poly(anhydride-esters) in bone and periodontal regeneration

Bioresorbable polymers offer the potential to deliver biologically active agents that selectively modulate wound healing in bone and periodontal regeneration. This preliminary study characterizes early wound healing in calvarial defects grafted with demineralized bone matrix (DBM) overlaid with membranes made from a novel class of non-steroidal anti-inflammatory drug (NSAID)-derived poly(anhydride-esters). These polymers chemically incorporate either salicylic acid (SA) or 5-(2',4'-difluorophenyl)salicylic acid (diflunisal) into the polymeric backbone and release the NSAIDs upon hydrolysis. Inflammatory cell infiltrate in response to the novel NSAID-derived polymers was compared to defects grafted with DBM alone at 10 days and to defects grafted with DBM and overlaid with poly(lactic acid) (PLA; Atrisorb) at 21 days in 8 Wistar rats (350-450 g). Histological analysis of the calvarial sites at 10 days revealed that the NSAID-derived polymers were associated with moderate levels of inflammation similar to defects grafted without polymer (2.3 +/- 0.96 versus 2.0 +/- 0.82, respectively), consistent with the therapeutic activity of salicylic acid and diflunisal. Defects grafted with DBM and overlaid with NSAID-derived polymers at 21 days exhibited mild inflammation; whereas, defects treated with PLA were consistently associated with moderate to severe inflammatory cell infiltrate (1.8 +/- 0.50 versus 2.7 +/- 0.58, respectively). Histopathological findings, such as foreign body giant cells or fibrous encapsulation, were not observed in any defects with NSAID-derived polymers. Cellular features consistent with bone formation were found in all grafted defects. This novel class of non-steroidal anti-inflammatory drug-derived poly(anhydride-esters) were well tolerated and elicited no demonstrable increase in inflammation, as shown with PLA, during osseous wound healing in a regenerative application.     

Non-steroidal anti-inflammatory drugs antagonise the constipating effects of tramadol

We report an antagonistic interaction between tramadol and non-steroidal anti-inflammatory drugs (NSAIDs), on gastrointestinal transit in rats. Transit was evaluated with charcoal and results are expressed as %inhibition. Tramadol and morphine had ED(50)s of 120.70+/-9.54 and 3.20+/-0.26 mg/kg, respectively, while metamizol (85 mg/kg), paracetamol (100 mg/kg) or ibuprofen (50 mg/kg) had no effect. All combinations of tramadol plus an NSAID, resulted in a rightward, non-parallel shift of the curves, which showed (two-way analysis of variance, ANOVA) significant differences from tramadol alone for the dose (P<0.0001), the drug (P<0.0001) and their interaction (P<0.0001), demonstrating antagonism. No interaction was present for morphine plus NSAIDs. The results demonstrate that NSAIDs antagonise the constipating effects of tramadol in rats, a fact that could have clinical relevance when combinations of these drugs are used in pain management in humans.     

Effects of non-steroidal anti-inflammatory agents on human neutrophil functions in vitro and in vivo

Human blood neutrophils exposed to appropriate stimuli aggregate, degranulate and generate superoxide anion (O2-). These responses are anteceded by mobilization of membrane-associated calcium, monitored as a decrease in fluorescence of cells preloaded with chlortetracycline (CTC). We studied the effects, both in vitro and in vivo, of non-steroidal anti-inflammatory agents (aspirin, indomethacin, ibuprofen and piroxicam) on these neutrophil responses to three stimuli: a chemoattractant, N-formyl-methionyl-leucyl-phenylalanine (FMLP); a tumor promotor, phorbol myristate acetate (PMA); and a lectin, concanavalin A (Con A). The effects of these drugs were compared with those of two polyenoic inhibitors of arachidonate metabolism: eicosatrienoic acid (ETI) and eicosatetraynoic acid (ETYA). The pattern of inhibition of neutrophil functions varied both with inhibitor and the nature of the stimulus. Thus, aspirin, piroxicam, ETYA and ETI inhibited neutrophil aggregation, degranulation, and O2- generation in response to FMLP, whereas ibuprofen inhibited only aggregation and degranulation and indomethacin only inhibited aggregation. None of the agents inhibited aggregation or degranulation induced by PMA or Con A: only piroxicam inhibited O2- generation in response to PMA or Con A. ETI and ibuprofen inhibited decrements of CTC fluorescence induced by FMLP, but whereas ETI inhibited the CTC response to PMA or Con A, ibuprofen was without effect. The agents had varying effects on binding of the stimulus [( 3H]FMLP, [3H]Con A), but these did not correlate with neutrophil responses to the ligands. Neutrophils from subjects taking therapeutic doses of ibuprofen, indomethacin, or piroxicam showed profiles of inhibited responses to FMLP similar to those observed with these agents in vitro. These data suggest that, although non-steroidal anti-inflammatory agents may inhibit discrete neutrophil functions both in vitro and in vivo, their effects do not duplicate those of polyenoic inhibitors of arachidonate metabolism. Moreover, since the susceptibility of neutrophils differed not only with respect to each inhibitor, but also to the stimulus, it is unlikely that all neutrophil responses are necessarily linked by a common pathway that is blocked by inhibitors of arachidonic acid metabolism.     

Differential inhibition of human neutrophil functions. Role of cyclic AMP-specific, cyclic GMP-insensitive phosphodiesterase.

Multiple molecular forms of cyclic nucleotide phosphodiesterase have been characterized in various tissues and cells according to their substrate specificity, intracellular location, and calmodulin dependence. The purpose of this study was to evaluate the possible involvement of different molecular forms of phosphodiesterase in regulating the respiratory burst and lysosomal enzyme release responses of human neutrophils. Treatment with the selective cyclic AMP-specific, cyclic GMP-insensitive phosphodiesterase inhibitors Ro 20-1724 or rolipram, or the nonselective phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX), resulted in inhibition of respiratory burst stimulated by the chemoattractants formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) (IC50 values: 0.71-17 microM) and complement fragment C5a (IC50 values: 61-93 microM), but did not inhibit phagocytosis-stimulated respiratory burst (less than 10% inhibition at 100 microM). Selective inhibitors of calmodulin-dependent phosphodiesterase (ICI 74,917), calmodulin-insensitive, cyclic GMP-specific phosphodiesterase (M & B 22,948), cyclic GMP-stimulated phosphodiesterase (AR-L 57), or cyclic AMP-specific, cyclic GMP-inhibited phosphodiesterase (amrinone and cilostamide) exhibited little or no inhibitory effect on FMLP- or phagocytosis-stimulated respiratory burst (0-42% inhibition at 100 microM). Regulation of neutrophil activation by phosphodiesterase was also response specific, as Ro 20-1724, rolipram and IBMX were less potent inhibitors of FMLP-induced lysosomal enzyme release (0-14% inhibition at 100 microM). Analysis of human neutrophil preparations confirmed the existence of a cyclic AMP-specific, cyclic GMP-insensitive phosphodiesterase, which was associated with the particulate fraction of the cell. These results demonstrate a role for the cyclic AMP-specific, cyclic GMP-insensitive phosphodiesterase in the regulation of human neutrophil functions, which appears to be both stimulus specific and response specific.     

Non-steroidal anti-inflammatory drugs and upper gastrointestinal bleeding,a post-marketing surveillance case-control study

A post-marketing surveillance case-control study was set up and applied in an Italian hospital network to quantify the risk of upper gastrointestinal bleeding (UGB) and exposure to non-steroidal anti-inflammatory drugs (NSAIDs). During the period of study 441 cases of UGB and 1323 controls were recruited. The odds ratios associated with NSAIDs use were estimated for intake occurring over two different periods of time prior to hospital admission (i.e. during the preceding week and month). A strong association emerged for aspirin intake, both in the week (OR_MLR = 11.2; 95% CI 7.8–16.9) and in the month (OR_MLR = 6.9; 95% CI 4.6–10.2) preceding hospital admission. A significant increase in the risk of UGB and use of diclofenac, naproxen and ibuprofen, and indomethacin was also found in the two exposure periods considered, while for piroxicam a significant association was only apparent in the analysis of 1-month exposure. As expected, paracetamol and pyrazolone derivatives were not associated with UGB. This pilot experience has shown the feasibility of setting up a multicentre post-marketing surveillance programme and of establishing a network for drug monitoring within the Italian National Health Service, capable of providing a thorough evaluation of the benefit/risk profile of drugs.     

A study of the novel anti-inflammatory agent florifenine topical anti-inflammatory activity and influence on arachidonic acid metabolism and neutrophil functions

We have evaluated the effects of the novel anti-inflammatory agent florifenine, 2-(1-Pyrrolidinyl)ethyl N-[7-(trifluoromethyl)-4-quinolyl]anthranilate, on topical inflammation in mice, free radical-mediated reactions, arachidonic acid metabolism and some neutrophil functions. Topical administration of florifenine produced dose-related anti-inflammatory activity in 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced ear oedema and with a lower potency, in the response induced by arachidonic acid (AA). Florifenine also inhibited neutrophil migration and PGE₂ content in the inflammed ears. In human whole blood, florifenine was a potent and selective inhibitor of TXB₂ generation. This anti-inflammatory agent did not exert antioxidant effects but inhibited elastase release in human neutrophils without affecting superoxide anion generation. Florifenine administration to mice dose-dependently inhibited leukocyte migration and PGE₂ levels in the air pouch inflammation induced by zymosan. These results demonstrate the topical anti-inflammatory activity of florifenine and provide a basis for understanding the mechanisms involved in the inhibitory effects of this agent on inflammatory responses.     

An anti-inflammatory ent-kaurane from the stems of Annona squamosa that inhibits various human neutrophil functions

We have previously shown that 11 ent-kauranes isolated from the stems of Annona squamosa exhibited immunomodulating effects in leukocytes. In this study, a cellular model using isolated human neutrophils, which are important in the pathogenesis of rheumatoid arthritis, ischemia-reperfusion injury, chronic obstructive pulmonary disease, asthma and other inflammatory diseases, was established in order to elucidate the anti-inflammatory functions of 16beta,17-dihydroxy-ent-kauran-19-oic acid (1). Reactive oxygen species (ROS) and granule proteases produced by neutrophils contribute to the pathogenesis of inflammatory diseases. Compound 1 inhibited the generation of superoxide anion, the formation of ROS, and the release of elastase in formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-activated human neutrophils in a concentration-dependent manner with IC (50) values of 3.95 +/- 0.68, 12.20 +/- 2.16, and 12.52 +/- 2.26 microM, respectively. The anti-inflammatory actions were not attributable to cytotoxicity because incubation of the neutrophils with 1 did not result in lactate dehydrogenase release. Compound 1 did not display antioxidant or superoxide anion-scavenging activity. Furthermore, neither subcellular NADPH oxidase activity nor cAMP-dependent pathways were altered by 1. Compound 1 significantly inhibited rapid calcium release from internal calcium stores induced by FMLP but not by thapsigargin. In summary, the presented results indicate that the inhibitory effects of 1 on respiratory burst and degranulation of human neutrophils are through the inhibition of cytosolic calcium mobilization, but not via the cAMP-dependent pathways.