Eimerian and capillariid infection in farmed ring-necked pheasants (Phasianus colchicus karpowi) in Ehime, Japan, with special reference to their phylogenetic relationships with congeners

We performed a parasitological examination of the gastrointestinal tract of farmed ring-necked pheasants (Phasianus colchicus karpowi) on two farms in Ehime, Japan. Fecal examination through flotation and sedimentation methods (43, 103, and 50 samples in three consecutive years from 2020, respectively) detected coccidian oocysts (5-58%), or capillarid (40-56%) and heterakid eggs (45-72%). Following artificial sporology, most sporulated coccidian oocysts were ellipsoidal without micropyle nor residuum, but with 1-3 polar refractile granules, morphologically reminiscent of Eimeria phasiani (Apicomplexa: Eucoccidiorida: Eimeriidae). Intensive sequencing of mitochondrial cytochrome c oxidase subunit I gene (cox-1) using pan-eimerian primers and multiple oocyst samples from different pheasants indicated a single species. We characterized, for the first time, the cox-1 sequence of E. phasiani, known to be prevalent in wild and captive ring-necked pheasants worldwide. Worm recovery under a dissection microscope revealed two capillariid and one heterakid nematode species: Eucoleus perforans (Nematoda: Trichocephalida: Capillariidae) in the esophageal epithelium (prevalence, 8-73%), Capillaria phasianina (Capillariidae) in the cecal mucosa (10-87%), and Heterakis gallinarum (Nematoda: Ascaridida: Heterakidae) in the cecal lumen (69-88%). The small subunit ribosomal RNA gene (SSU rDNA) of E. perforans was perfectly identical to that in a previous isolate from farmed Japanese green pheasants (Phasianus colchicus versicolor) at a distant locality in Japan. The SSU rDNA of C. phasianina was characterized, for the first time, demonstrating a sister relationship with Capillaria anatis, parasites found in the ceca of domestic ducks, geese, and various wild anatid birds.

Impact of Indazole scaffold as Antibacterial and Antifungal agent

Heterocycles consisting of nitrogen atom, Indazole, is a pungent, biological, heterocyclic, bicyclic compounds possessing electron rich portions. Indazole composed of two nitrogen atoms put under the azoles family, further called as isoindazolone. It is a colorless solid nitrogen-containing heterocyclics with atomic formula C7H6N2 are extraordinary scaffolds, still identified as isoindazole. So, analogs of Indazole have experienced expert approach in later times because of its special biological properties, such as antimicrobial, anti-inflammatory, anticancer, anti-HIV, and antihypertensive actions. 1H-indazole and 2H-indazole are two toutomeric forms of Indazole. Sometimes, indazole produced three tautomeric forms that are 1H, 2H and 3H tautomers of indazole. 1H-indazole is reliable than 2H-indazole. We should note that a series of derivatives of indazole having 2H toutomers follow hybridization of cyclic systems and act as anti-inflammatory as well as antimicrobial compounds. It formed Indazole itself and derivatives of Indazole in natural products. A sequence of N-methyl-3-aryl inazoles has dominant against bacterial strains like xanthomon as campstris, Baillus cereus, Escherichia coli, Bacillus megaterium and a fungal strain candida albicans found by in-vitro antimicrobial study of indazole derivatives.

Novel benzofurane-pyrazole derivatives with anti-inflammatory, cyclooxygenase inhibitory and cytotoxicity evaluation

Novel benzofurane-pyrazolone hybrids have been synthesized for evaluating their anti-inflammatory and cytotoxic properties. 4-(2-chloroacetyl)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one were reacted with α-hydroxy aldehyde or α-hydroxy ketone derivatives to obtain nine novel pyrazolone derivatives. Structures were successfully elucidated by ¹H NMR, ¹³C NMR, IR and HRMS. Enzyme inhibitory activity was measured on cyclooxygenases (COXs) as considered to address anti-inflammatory activity. Compound 2 showed the highest activity on both COX-1 and COX-2 subtypes with 12.0 μM and 8.0 μM IC₅₀, respectively. This activity was found close to indomethacin COX-2 inhibition measured as 7.4 μM IC₅₀. Rest of the compounds (1, 3-9) showed 10.4-28.1 μM IC₅₀ on COX-2 and 17.0-35.6 μM IC₅₀ on COX-1 (Compound 1 has no activity on COX-1). Tested compounds (1-9) showed activity on NO production. Only compound was the 4, which showed a low inhibition on IL-6 levels. Cell viability was up to 60% at 100 μM for all compounds (1-9) on RAW 264.7 and NIH3T3 cell lines, thus compounds were reported to be noncytotoxic.

Chabaudstrongylus ninhae (Trichostrongylidae: Cooperiinae) and Oesophagostomum muntiacum (Chabertiidae: Oesophagostominae) in feral alien Reeves's muntjacs on Izu-Oshima Island, Tokyo, Japan

The naturalization of alien Reeves's muntjacs (Muntiacus reevesi) on Izu-Oshima Island, Tokyo, Japan, has proceeded intensively over the last five decades. To clarify whether the gastrointestinal helminths of these animals were brought from their original endemic area or were newly acquired in Japan, 32 Reeves's muntjacs trapped on the island were parasitologically examined. In addition to Gongylonema pulchrum in the oesophagus (34.4% prevalence), Chabaudstrongylus ninhae (Dróżdż, 1967) (Trichostrongylidae: Cooperiinae) and Oesophagostomum muntiacum Jian, 1989 (Chabertiidae: Oesophagostominae) were prevalent in the small (28.1%) and large (46.9%) intestines, respectively. For the first time, these trichostrongylid or chabertiid worms were genetically characterized based on partial nucleotide sequences of the nuclear ribosomal RNA gene (rDNA) and mitochondrial DNA cytochrome c oxidase subunit 1 gene (cox-1), and the phylogenetic relationships with other members of their family were explored. Since these two intestinal nematode species are inherent in muntjacs, this study demonstrates a new distribution of exotic helminth species in Japan in accordance with the naturalization of alien mammalian hosts. The molecular genetic data collected here could assist the taxonomic assessment of morphological variants in different Muntiacus spp. and/or of different geographical origins. Furthermore, our data may help to define the phylogenetic relationships among such isolates.

First record of Gongylonema nepalensis in domestic and wild ruminants in Europe

The gullet worm, Gongylonema pulchrum, is cosmopolitan in distribution, infecting a variety of mammals including domestic and wild ruminants. Gongylonema nepalensis recently collected from the esophageal epithelium of water buffaloes in Nepal was separated from G. pulchrum based on its distinctly shorter left spicule relative to body length and unique nucleotide sequences of the ribosomal RNA gene (rDNA) and the mitochondrial cytochrome c oxidase subunit 1 gene (cox-1). During meat inspections at four abattoirs on Sardinia Island, Italy, 25 Gongylonema worms were collected from one each individual of cattle (n=8), sheep (n=7), goats (n=4), and mouflon (Ovis aries musimon; n=6), and characterized morphologically and genetically. Intriguingly, all of the collected worms from these ruminants were G. nepalensis, exhibiting comparable body lengths to G. pulchrum in cattle from other regions but with significantly shorter left spicules like G. nepalensis (less than 20.9% of the entire body length in contrast to 21.8-65.6%, the reported proportion of G. pulchrum). Furthermore, the rDNA nucleotide sequences of these worms from different ruminant species on Sardinia Island were almost identical to each other and to Nepalese G. nepalensis isolates. With the exception of one worm from a sheep (displaying a single nucleotide substitution), the 369-bp cox-1 nucleotide sequences of all the Sardinian G. nepalensis isolates from the different host sources were absolutely identical, forming a clade with Nepalese G. nepalensis isolates and not G. pulchrum isolates. The present study reveals that G. nepalensis is not a local parasite in the Indian subcontinent (Nepal), but instead has a certain geographical distribution in Europe and takes several ruminant species as a definitive host.

Intraspecific and interspecific genetic variation of Gongylonema pulchrum and two rodent Gongylonema spp. (G. aegypti and G. neoplasticum), with the proposal of G. nepalensis n. sp. for the isolate in water buffaloes from Nepal

The gullet worm (Gongylonema pulchrum) has been recorded from a variety of mammals worldwide. In an earlier study, we demonstrated two separate transmission cycles in cattle (Bos taurus) and wild mammals in Japan based on nucleotide sequences of the ribosomal RNA gene (rDNA) and cytochrome c oxidase subunit I (cox-1) region of mitochondrial DNA of multiple isolates of different origins. Our earlier study additionally demonstrated two major cox-1 haplotypes of G. pulchrum prevalent in cattle in Japan. In the present study, we collected G. pulchrum from cattle and goats (Capra hircus) in Alashan League, Inner Mongolia, China; Gongylonema aegypti from spiny mice (Acomys dimidiatus) in the Sinai Peninsula, Egypt; and Gongylonema neoplasticum from a black rat (Rattus rattus) in Okinawa Island, Japan, to analyze their genetic relationships with G. pulchrum in Japan. The gullet worms from Alashan League had almost identical rDNA nucleotide sequences and two cox-1 haplotypes as seen in G. pulchrum from the cattle in Japan. The two rodent Gongylonema spp. had distinct rDNA nucleotide sequences compared with those of G. pulchrum; only the 18S and 5.8S rDNA sequences showed high identities at 97.2-98.7%, while the remaining sequences were less than 75% identical. The 18S, 5.8S, and 28S rDNA sequences of the two rodent Gongylonema spp. showed nucleotide identities of 99.8% (1811/1814), 100% (158/158), and 98.9% (3550/3590), respectively. The cox-1 regions showed 91.6% (338/369)-92.1% (340/369) identities, with completely identical amino acid sequences. The genetic diversities of three distinct Gongylonema spp. and their possible intraspecific genetic variation may allow us to resolve the taxonomic position of Gongylonema spp. which display few obvious morphological differences from their congeners. Consequently, the Gongylonema isolate from water buffaloes (Bubalus bubalis) in Nepal reported in our previous study is concluded to be a new species, and Gongylonema nepalensis n. sp. is erected for it.

Cyclooxygenase (COX) Inhibitors and the Newborn Kidney

This review summarizes our current understanding of the role of cyclo-oxygenase inhibitors (COXI) in influencing the structural development as well as the function of the developing kidney. COXI administered either during pregnancy or after birth can influence kidney development including nephronogenesis, and can decrease renal perfusion and ultrafiltration potentially leading to acute kidney injury in the newborn period. To date, which COX isoform (COX-1 or COX-2) plays a more important role in during fetal development and influences kidney function early in life is not known, though evidence points to a predominant role for COX-2. Clinical implications of the use of COXI in pregnancy and in the newborn infant are also evaluated herein, with specific reference to the potential effects of COXI on nephronogenesis as well as newborn kidney function.

Genetic variation in inflammatory pathways is related to colorectal cancer survival

PURPOSE

Prognosis of patients with colorectal cancer (CRC) is associated with systemic inflammation, and anti-inflammatory drugs can reduce both CRC incidence and mortality. Genetic variation in proinflammatory pathways can affect an individual's CRC risk. However, few studies have investigated the prognostic importance of this genetic variation in CRC patients.

EXPERIMENTAL DESIGN

We investigated the association between CRC survival and genetic variation in proinflammatory pathways among patients from the Puget Sound Surveillance Epidemiology and End Results registry. Single-nucleotide polymorphisms were genotyped in five genes (PTGS-1, PTGS-2, MRP4, NFκB, and IκBKβ). Vital status was ascertained through linkage to the National Death Index. Cox proportional hazards regression was used to calculate HRs and 95% confidence intervals (CI). The false discovery rate method of Benjamini and Hochberg was applied to address multiple testing.

RESULTS

Four PTGS-1 variants were associated with CRC survival. One, G>A intron 9 (rs1213266), was associated with approximately 50% lower CRC mortality (HR(AA/AG vs. GG) = 0.48; 95% CI, 0.25-0.93). Three variants, including L237M, resulted in significantly elevated CRC mortality risk, with HRs ranging from approximately 1.5 to 2.0. Two variants in IκBKβ, including R526Q, were significantly associated with CRC survival. Correction for multiple testing indicated that variants in both PTGS-1 and IκBKβ are reproducibly associated with CRC survival.

CONCLUSION

Our findings suggest that genetic variation in proinflammatory pathways may be important for CRC prognosis. This investigation represents one of the first descriptions of the relationship between inherited polymorphisms and mortality in CRC patients and provides a starting point for further research.

Isolation and evaluation of kaempferol glycosides from the fern Neocheiropteris palmatopedata

Kaempferol glycosides, named palmatosides A (1), B (2) and C (3), together with three known kaempferol glycosides, multiflorins A (4) and B (5), and afzelin (6), were isolated from the roots of the fern Neocheiropteris palmatopedata. Palmatosides A (1) and B (2) each possessed an unusual sugar moiety containing a 4,4-dimethyl-3-oxo-butoxy substituent group. The isolated compounds were evaluated for their cancer chemopreventive potential based on their ability to inhibit tumor necrosis factor alpha (TNF-alpha)-induced NF-kappaB activity, nitric oxide (NO) production, aromatase, quinone reductase 2 (QR2) and COX-1/-2 activities. Palmatosides B (2) and C (3) inhibited TNF-alpha-induced NF-kappaB activity with IC(50) values of 15.7 and 24.1 microM, respectively; multiflorin A (4) inhibited aromatase enzyme with an IC(50) value of 15.5 microM; afzelin (6) showed 68.3% inhibition against QR2 at a concentration of 11.5 microg/ml; palmatoside A (1) showed 52% inhibition against COX-1 enzyme at a concentration of 10 microg/ml; and multiflorin B (5) showed 52% inhibition against nitric oxide production at a concentration of 20 microg/ml. In addition, compounds 3-6 were shown to bind QR2 enzyme using LC-MS ultrafiltration binding assay.

The effect of non-steroidal anti-inflammatory agents on behavioural changes and cytokine production following systemic inflammation: Implications for a role of COX-1

Systemic inflammation gives rise to metabolic and behavioural changes, largely mediated by pro-inflammatory cytokines and prostaglandin production (PGE(2)) at the blood-brain barrier. Despite numerous studies, the exact biological pathways that give rise to these changes remains elusive. This study investigated the mechanisms underlying immune-to-brain communication following systemic inflammation using various anti-inflammatory agents. Mice were pre-treated with selective cyclo-oxygenase (COX) inhibitors, thromboxane synthase inhibitors or dexamethasone, followed by intra-peritoneal injection of lipopolysaccharide (LPS). Changes in body temperature, open-field activity, and burrowing were assessed and mRNA and/or protein levels of inflammatory mediators measured in serum and brain. LPS-induced systemic inflammation resulted in behavioural changes and increased production of IL-6, IL-1beta and TNF-alpha, as well as PGE(2) in serum and brain. Indomethacin and ibuprofen reversed the effect of LPS on behaviour without changing peripheral or central IL-6, IL-1beta and TNF-alpha mRNA levels. In contrast, dexamethasone did not alter LPS-induced behavioural changes, despite complete inhibition of cytokine production. A selective COX-1 inhibitor, piroxicam, but not the selective COX-2 inhibitor, nimesulide, reversed the LPS-induced behavioural changes without affecting IL-6, IL-1beta and TNF-alpha protein expression levels in the periphery or mRNA levels in the hippocampus. Our results suggest that the acute LPS-induced changes in burrowing and open-field activity depend on COX-1. We further show that COX-1 is not responsible for the induction of brain IL-6, IL-1beta and TNF-alpha synthesis or LPS-induced hypothermia. Our results may have implications for novel therapeutic strategies to treat or prevent neurological diseases with an inflammatory component.

Acute and chronic estradiol replacements differentially alter corticosterone and COX-mediated responses to an inflammatory stimulus in female rats

INTRODUCTION

This study aimed to determine whether the previously reported differential effects of estradiol on inflammation-induced behavioral responses are in part explained through differential activation of the corticosterone-cyclooxygenase (CORT-COX) regulatory pathway.

METHODS

Prostaglandin E2 (PGE2), COX, and CORT levels were analyzed before and after a formalin administration (1% vs. 5%, representing different intensities of inflammatory stimuli).

RESULTS

In vehicle-treated rats, chronic estradiol administration increased corticosterone, and decreased COX and PGE2. After acute estradiol administration, although corticosterone serum levels were increased, COX protein levels were unchanged. In rats treated with formalin, PGE2 serum levels were higher in rats administered 5% formalin than vehicle- and 1%-treated rats. Significant correlations were observed between PGE2 serum levels, CORT serum levels, and COX protein levels.

CONCLUSIONS

Our results suggest that the administration of exogenous estradiol may mediate inflammatory responses by regulating the levels of PGE2 and/or CORT release, thereby mediating the nociceptive response to an inflammatory stimulus.

Heme-a, the heme prosthetic group of cytochrome c oxidase, is increased in Alzheimer's disease

Heme-a, is the heme prosthetic group of cytochrome c oxidase (COX), the terminal complex of the mitochondrial electron transport chain. We measured heme-a levels in postmortem brain tissue from nine patients diagnosed with dementia: Alzheimer's disease (AD) was the primary diagnosis in five, AD/diffuse Lewy body disease (DLBD) was diagnosed in two, DLBD was diagnosed in one, and DLBD (severe)/AD (mild) was diagnosed in one. Eight non-demented patients who died from non-neurological causes served as controls. When the primary diagnosis was AD (AD and AD/DLBD), levels of cerebral heme-a were increased almost two-fold on a protein basis compared to controls (p<0.001). Using perfused and non-perfused rats we showed that measured levels of cerebral heme-a were unaffected by the presence of blood in brain tissue. In mice we showed that levels of cerebral heme-a were unaffected by 24h of storage at 4 degrees C prior to freezing. These animal studies suggest that increased levels of cerebral heme-a in AD were not due to blood in postmortem brain or variation in postmortem interval.

Antiplatelet Effect and Selective Binding to Cyclooxygenase (COX) by Molecular Docking Analysis of Flavonoids and Lignans

The known flavonoids ginkgetin (1), taiwanhomoflavone A (2), taiwanhomoflavone B (3), and taiwanhomoflavone C (4) and eight known lignans: justicidin B (9), justicidin C (10), justicidin D (11), chinensinaphthol methyl ether (12), procumphthalide A (13), procumbenoside A (15), and ciliatosides A (16) and B (17) were isolated from Cephalotaxus wilsoniana and Justicia species, respectively. The antiplatelet effects of the above constituents on human platelet-rich plasma (PRP) were evaluated. Of the compounds tested on human PRP, compounds 1, 4, 9, and 11 showed inhibition of secondary aggregation induced by adrenaline. Compound 1 had an inhibitory effect on cyclooxygenase-1 (COX-1). Molecular docking studies revealed that 1 and the related compounds apigenin (5), cycloheterophyllin (6), broussoflavone F (7), and quercetin (8) were docked near the gate of active site of COX-1. It indicated that the antiplatelet effect of 1, 4, 9, and 11 is partially owed to suppression of COX-1 activity and reduced thromboxane formation. Flavonoids, 1, 5, 6, 7, and 8 may block the gate of the active site of COX-1 and interfere the conversion of arachidonic acid to prostaglandin (PG) H₂ in the COX-1 active site.

Comparative protection against rat intestinal reperfusion injury by a new inhibitor of sPLA2, COX-1 and COX-2 selective inhibitors, and an LTC4 receptor antagonist

(1) A new group IIa sPLA2 inhibitor was compared with selective inhibitors of COX-1, COX-2 and an LTC4 antagonist for effects on local and remote tissue injuries following ischaemia and reperfusion (I/R) of the small intestine in rats. (2) In an acute model of ischaemia (30 min) and reperfusion (150 min) injury in the absence of inhibitors, there was significant intestinal haemorrhage, oedema and mucosal damage, neutropenia, elevated serum levels of aspartate aminotransferase (AST) and hypotension. (3) Preischaemic treatment with the inhibitor of sPLA2 (Group IIa), at 5 mg kg-1 i.v. or 10 mg kg-1 p.o. significantly inhibited I/R-induced neutropenia, the elevation of serum levels of AST, intestinal oedema and hypotension. (4) Pretreatment with the COX-2 inhibitor celebrex (10 mg kg-1 i.v.) and the LTC4 antagonist zafirlukast (1 mg kg-1 i.v.) also showed marked improvement with I/R-induced AST, oedema and neutropenia. Hypotension was only reduced by the LTC4 antagonist. The COX-1 inhibitor flunixin (1 mg kg-1 i.v.) did not effect improvement in the markers of tissue injury. (5) Histological examination of rat I/R injury showed that all of the drugs offered some protection to the mucosal layer damage compared to no drug treatment. Given i.v., the sPLA2 inhibitor was more effective than either the COX-1 or COX-2 inhibitors in preventing rat I/R injury. (6) These results indicate that a potent new inhibitor of sPLA2 (group IIa) protects the rat small intestine from I/R injury after oral or intravenous administration. COX-2 and LTC4 inhibitors also showed some beneficial effects against intestinal I/R injury. Our study suggests that sPLA2 (Group IIa) may have a pathogenic role in intestinal I/R in rats.

Assessment of the relative contribution of COX-1 and COX-2 isoforms to ischemia-induced oxidative damage and neurodegeneration following transient global cerebral ischemia

We investigated the relative contribution of COX-1 and/or COX-2 to oxidative damage, prostaglandin E2 (PGE2) production and hippocampal CA1 neuronal loss in a model of 5 min transient global cerebral ischemia in gerbils. Our results revealed a biphasic and significant increase in PGE2 levels after 2 and 24-48 h of reperfusion. The late increase in PGE2 levels (24 h) was more potently reduced by the highly selective COX-2 inhibitor rofecoxib (20 mg/kg) relative to the COX-1 inhibitor valeryl salicylate (20 mg/kg). The delayed rise in COX catalytic activity preceded the onset of histopathological changes in the CA1 subfield of the hippocampus. Post-ischemia treatment with rofecoxib (starting 6 h after restoration of blood flow) significantly reduced measures of oxidative damage (glutathione depletion and lipid peroxidation) seen at 48 h after the initial ischemic episode, indicating that the late increase in COX-2 activity is involved in the delayed occurrence of oxidative damage in the hippocampus after global ischemia. Interestingly, either selective inhibition of COX-2 with rofecoxib or inhibition of COX-1 with valeryl salicylate significantly increased the number of healthy neurons in the hippocampal CA1 sector even when the treatment began 6 h after ischemia. These results provide the first evidence that both COX isoforms are involved in the progression of neuronal damage following global cerebral ischemia, and have important implications for the potential therapeutic use of COX inhibitors in cerebral ischemia.

Pharmacokinetics of diclofenac and inhibition of cyclooxygenases 1 and 2: no relationship to the CYP2C9 genetic polymorphism in humans

AIMS

The cytochrome P450 enzyme CYP2C9 catalyses the 4'-hydroxylation of the nonsteroidal analgesic drug diclofenac in humans. We studied the influences of the known amino acid variants, CYP2C9*2 (Arg144Cys) and CYP2C9*3 (Ile359Leu), on diclofenac pharmacokinetics after a 50-mg oral dose of diclofenac in healthy volunteers. As a surrogate marker of diclofenac activity, the ex vivo formation of prostaglandin E2 and thromboxane B2, which reflects COX-2 and COX-1 activity, was measured.

METHODS

Genotyping was performed in 516 healthy volunteers to obtain 20 participants with all allelic combinations of the two CYP2C9 variants Arg144Cys (*2) and Ile359Leu (*3). Diclofenac and 4'-hydroxydiclofenac were quantified in plasma by reversed phase h.p.l.c. after oral intake of 50 mg diclofenac. Concentrations of thromboxane B2 (TxB2) and prostaglandin E2 (PGE2) were measured by immunoassays.

RESULTS

There was no evidence of impaired metabolism of oral diclofenac in heterozygous and homozygous carriers of the CYP2C9 alleles *2 and *3 compared with the wild type (mean CL/F (95% CI) 20.5 (11, 30) l h-1 for *1/*1, 29.9 (19, 40) l h-1 for *1/*2, 30.0 (4, 56) l h-1 for *2/*2, 22.6 (12, 33) l h-1 for *1/*3, 23.5 (11, 37) l h-1 for *3/*3 and 37.3 (-15, 89) l h-1 in *2/*3). Furthermore, plasma concentrations of the metabolite 4'-hydroxydiclofenac were not lower in carriers of the CYP2C9 low-activity alleles *2 and *3 compared with carriers of the CYP2C9*1/*1 genotype. Marked diclofenac mediated inhibition of COX-1- and COX-2 activity was detected in all individuals independent of CYP2C9 genotype.

CONCLUSIONS

Polymorphisms of the CYP2C9 gene had no discernible effect on the pharmacokinetics and pharmacodynamics of diclofenac. The question of whether enzymes other than CYP2C9 play a major role in diclofenac 4'-hydroxylation in vivo or whether 4'-hydroxylation is not a rate-limiting step in diclofenac elimination in vivo, or whether the effect of the CYP2C9 polymorphisms is substrate-dependent, needs further investigation.

Effects of non-steroidal anti-inflammatory drugs on cyclo-oxygenase and lipoxygenase activity in whole blood from aspirin-sensitive asthmatics vs healthy donors

1. Cyclo-oxygenase (COX) and lipoxygenase (LO) share a common substrate, arachidonic acid. Aspirin and related drugs inhibit COX activity. In a subset of patients with asthma aspirin induces clinical symptoms associated with increased levels of certain LO products, a phenomenon known as aspirin-sensitive asthma. The pharmacological pathways regulating such responses are not known. 2. Here COX-1 and LO activity were measured respectively by the formation of thromboxane B(2) (TXB(2)) or leukotrienes (LT) C(4), D(4) and E(4) in whole blood stimulated with A23187. COX-2 activity was measured by the formation of prostaglandin E(2) (PGE(2)) in blood stimulated with lipopolysaccharide (LPS) for 18 h. 3. No differences in the levels of COX-1, COX-2 or LO products or the potency of drugs were found in blood from aspirin sensitive vs aspirin tolerant patients. Aspirin, indomethacin and nimesulide inhibited COX-1 activity, without altering LO activity. Indomethacin, nimesulide and the COX-2 selective inhibitor DFP [5,5-dimethyl-3-(2-isopropoxy)-4-(4-methanesulfonylphenyl)-2(5H)-furanone] inhibited COX-2 activity. NO-aspirin, like aspirin inhibited COX-1 activity in blood from both groups. However, NO-aspirin also reduced LO activity in the blood from both patient groups. Sodium salicylate was an ineffective inhibitor of COX-1, COX-2 or LO activity in blood from both aspirin-sensitive and tolerant patients. 4. Thus, when COX activity in the blood of aspirin-sensitive asthmatics is blocked there is no associated increase in LO products. Moreover, NO-aspirin, unlike other NSAIDs tested, inhibited LO activity in the blood from both aspirin sensitive and aspirin tolerant individuals. This suggests that NO-aspirin may be better tolerated than aspirin by aspirin-sensitive asthmatics.

The growth of malignant keratinocytes depends on signaling through the PGE(2) receptor EP1

Recent discoveries shed light on the importance of prostaglandin (PG) production in the development of skin cancer. Work by Fischer et al. demonstrates that skin tumor promotion caused by ultraviolet B radiation can be decreased by up to 89% by blocking cyclooxygenase-2 (COX-2) with the drug Celecoxib. A similar study showed that Celecoxib can decrease new tumor formation by 44% in mice that already have tumors. These studies demonstrate the importance of COX-2 and PGs in the development of squamous cell carcinoma. We have explored growth signaling in a model of skin tumor progression. Because changes in PG production have been implicated in skin carcinogenesis, we examined this pathway. We found that malignant cell lines secrete more prostaglandin E(2) (PGE(2)) than the parental cells. We observed increased expression of COX-1 and -2. We also found that these cells express the PGE(2) receptors EP1 and EP4. When the cells are grown in the presence of indomethacin, the growth rate of the malignant cells is decreased. This effect can be reversed by addition of PGE(2) or an EP1 agonist to the medium. Thus, we have shown that skin tumor cells depend in part on PGE(2) signaling through the EP1 prostanoid receptor for their in vitro growth.

Ex vivo assay to determine the cyclooxygenase selectivity of non-steroidal anti-inflammatory drugs

1. In this study we describe experiments to establish ex vivo the selectivity of non-steroidal anti-inflammatory drugs (NSAIDs) given in vivo. 2. Anaesthetised (Inactin, 120 mg kg(-1)) male Wistar rats (220-250 g) received an i.v. dose of one of the following compounds (dose mg kg(-1)): aspirin (20), diclofenac (3), L-745,337 (30), nimesulide (15), salicylate (20), sulindac (10). Blood samples were taken before and up to 6 h after dosing and the plasma obtained from it was tested for its ability to inhibit prostanoid formation in IL-1beta-treated A549 cells (COX-2 system) and human washed platelets (COX-1 system). For control the same compounds were also added directly to the assay systems. 3. All drugs, except sodium salicylate, inhibited COX-1 and COX-2 when added directly to the test systems. Plasma from aspirin-treated rats was without effect on either COX-1 or COX-2, consistent with the rapid in vivo metabolism to salicylate. Conversely, plasma from sulindac-treated rats inhibited COX-1 and COX-2 with potencies according with in vivo metabolism to sulindac sulphide. Diclofenac was COX-1/2 non-selective when tested in vitro, but a slightly preferential inhibitor of COX-2 when tested ex vivo. Nimesulide was confirmed as preferential inhibitor of COX-2 both in vitro and ex vivo. L-745,337 was a selective COX-2 inhibitor when tested in vitro or ex vivo. 4. In conclusion, our experiments show clearly (a) NSAIDs inactivation, (b) activation of prodrugs, and (c) NSAIDs selectivity. Our assay provides useful information about the selectivity of NSAIDs that could be extended by the analysis of plasma samples taken from humans similarly treated with test drugs.

Cyclo-oxygenase isozymes in mucosal ulcergenic and functional responses following barrier disruption in rat stomachs

1. We examined the effects of selective and nonselective cyclo-oxygenase (COX) inhibitors on various functional changes in the rat stomach induced by topical application of taurocholate (TC) and investigated the preferential role of COX isozymes in these responses. 2. Rat stomachs mounted in ex vivo chambers were perfused with 50 mM HCl and transmucosal potential difference (p.d.), mucosal blood flow (GMBF), luminal acid loss and luminal levels of prostaglandin E2 (PGE2) were measured before, during and after exposure to 20 mM TC. 3. Mucosal application of TC in control rats caused a reduction in p.d., followed by an increase of luminal acid loss and GMBF, and produced only minimal damage in the mucosa 2 h later. Pretreatment with indomethacin (10 mg kg[-1], s.c.), a nonselective COX-1 and COX-2 inhibitor, attenuated the gastric hyperaemic response caused by TC without affecting p.d. and acid loss, resulting in haemorrhagic lesions in the mucosa. In contrast, selective COX-2 inhibitors, such as NS-398 and nimesulide (10 mg kg[-1], s.c.), had no effect on any of the responses induced by TC and did not cause gross damage in the mucosa. 4. Luminal PGE2 levels were markedly increased during and after exposure to TC and this response was significantly inhibited by indomethacin but not by either NS-398 or nimesulide. The expression of COX-1-mRNA was consistently detected in the gastric mucosa before and after TC treatment, while a faint expression of COX-2-mRNA was detected only 2 h after TC treatment. 5. Both NS-398 and nimesulide significantly suppressed carrageenan-induced rat paw oedema, similar to indomethacin. 6. These results confirmed a mediator role for prostaglandins in the gastric hyperaemic response following TC-induced barrier disruption, and suggest that COX-1 but not COX-2 is a key enzyme in maintaining 'housekeeping' functions in the gastric mucosa under both normal and adverse conditions.

Biochemical and pharmacological profile of a tetrasubstituted furanone as a highly selective COX-2 inhibitor

1. DFU (5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulphonyl)phenyl-2(5H)-furan one) was identified as a novel orally active and highly selective cyclo-oxygenase-2 (COX-2) inhibitor. 2. In CHO cells stably transfected with human COX isozymes, DFU inhibited the arachidonic acid-dependent production of prostaglandin E2 (PGE2) with at least a 1,000 fold selectivity for COX-2 (IC50 = 41 +/- 14 nM) over COX-1 (IC50 > 50 microM). Indomethacin was a potent inhibitor of both COX-1 (IC50 = 18 +/- 3 nM) and COX-2 (IC50 = 26 +/- 6 nM) under the same assay conditions. The large increase in selectivity of DFU over indomethacin was also observed in COX-1 mediated production of thromboxane B2 (TXB2) by Ca2+ ionophore-challenged human platelets (IC50 > 50 microM and 4.1 +/- 1.7 nM, respectively). 3. DFU caused a time-dependent inhibition of purified recombinant human COX-2 with a Ki, value of 140 +/- 68 microM for the initial reversible binding to enzyme and a kappa 2 value of 0.11 +/- 0.06 s-1 for the first order rate constant for formation of a tightly bound enzyme-inhibitor complex. Comparable values of 62 +/- 26 microM and 0.06 +/- 0.01 s-1, respectively, were obtained for indomethacin. The enzyme-inhibitor complex was found to have a 1:1 stoichiometry and to dissociate only very slowly (t1/2 = 1-3 h) with recovery of intact inhibitor and active enzyme. The time-dependent inhibition by DFU was decreased by co-incubation with arachidonic acid under non-turnover conditions, consistent with reversible competitive inhibition at the COX active site. 4. Inhibition of purified recombinant human COX-1 by DFU was very weak and observed only at low concentrations of substrate (IC50 = 63 +/- 5 microM at 0.1 microM arachidonic acid). In contrast to COX-2, inhibition was time-independent and rapidly reversible. These data are consistent with a reversible competitive inhibition of COX-1. 5. DFU inhibited lipopolysaccharide (LPS)-induced PGE2 production (COX-2) in a human whole blood assay with a potency (IC50 = 0.28 +/- 0.04 microM) similar to indomethacin (IC50 = 0.68 +/- 0.17 microM). In contrast, DFU was at least 500 times less potent (IC50 > 97 microM) than indomethacin at inhibiting coagulation-induced TXB2 production (COX-1) (IC50 = 0.19 +/- 0.02 microM). 6. In a sensitive assay with U937 cell microsomes at a low arachidonic acid concentration (0.1 microM), DFU inhibited COX-1 with an IC50 value of 13 +/- 2 microM as compared to 20 +/- 1 nM for indomethacin. CGP 28238, etodolac and SC-58125 were about 10 times more potent inhibitors of COX-1 than DFU. The order of potency of various inhibitors was diclofenac > indomethacin approximately naproxen > nimesulide approximately meloxicam approximately piroxicam > NS-398 approximately SC-57666 > SC-58125 > CGP 28238 approximately etodolac > L-745,337 > DFU. 7. DFU inhibited dose-dependently both the carrageenan-induced rat paw oedema (ED50 of 1.1 mg kg-1 vs 2.0 mg kg-1 for indomethacin) and hyperalgesia (ED50 of 0.95 mg kg-1 vs 1.5 mg kg-1 for indomethacin). The compound was also effective at reversing LPS-induced pyrexia in rats (ED50 = 0.76 mg kg-1 vs 1.1 mg kg-1 for indomethacin). 8. In a sensitive model in which 51Cr faecal excretion was used to assess the integrity of the gastrointestinal tract in rats, no significant effect was detected after oral administration of DFU (100 mg kg-1, b.i.d.) for 5 days, whereas chromium leakage was observed with lower doses of diclofenac (3 mg kg-1), meloxicam (3 mg kg-1) or etodolac (10-30 mg kg-1). A 5 day administration of DFU in squirrel monkeys (100 mg kg-1) did not affect chromium leakage in contrast to diclofenac (1 mg kg-1) or naproxen (5 mg kg-1). 9. The results indicate that COX-1 inhibitory effects can be detected for all selective COX-2 inhibitors tested by use of a sensitive assay at low substrate concentration. The novel inhibitor DFU shows the lowest inhibitory potency against COX-1, a consistent high selectivity of inhibition of COX-2 over COX-1 (>300 fold) with enzyme, whole cell and whole blood assays, with no detectable loss of integrity of the gastrointestinal tract at doses >200 fold higher than efficacious doses in models of inflammation, pyresis and hyperalgesia. These results provide further evidence that prostanoids derived from COX-1 activity are not important in acute inflammatory responses and that a high therapeutic index of anti-inflammatory effect to gastropathy can be achieved with a selective COX-2 inhibitor.

Selective induction of cyclo-oxygenase-2 activity in the permanent human endothelial cell line HUV-EC-C: biochemical and pharmacological characterization

1. Cyclo-oxygenase (COX), the enzyme responsible for the conversion of arachidonic acid (AA) to prostaglandin H2 (PGH2), exists in two forms, termed COX-1 and COX-2 which are encoded by different genes. COX-1 is expressed constitutively and is known to be the site of action of aspirin and other nonsteroidal anti-inflammatory drugs. COX-2 may be induced by a series of pro-inflammatory stimuli and its role in the development of inflammation has been claimed. 2. Endothelial cells are an important physiological source of prostanoids and the selective induction of COX-2 activity has been described for finite cultures of endothelial cells, but not for permanent endothelial cell lines. 3. The HUV-EC-C line is a permanent endothelial cell line of human origin. We have determined the COX activity of these cells under basal conditions and after its exposure to two different stimuli, phorbol 12-myristate 13-acetate (PMA) and interleukin-1 beta (IL-1 beta). 4. Both PMA and IL-1 beta produced dose- and time-dependent increases of the synthesis of the COX-derived eicosanoids. These increases were maximal after the treatment with 10 nM PMA for 6 to 9 h. Under these conditions, the main eicosanoid produced by the cells was PGE2. 5. The increase of COX activity by PMA or IL-1 beta correlated with an increase of the enzyme's apparent Vmax, whilst the affinity for the substrate, measured as apparent Km, remained unaffected. 6. Treatment of the cells with PMA induced a time-dependent increase in the expression of both COX-1 and COX-2 mRNAs. Nevertheless, this increase was reflected only as an increase of the COX-2 isoenzyme at the protein level. 7. The enzymatic activity of the PMA-induced COX was measured in the presence of a panel of enzyme inhibitors, and the IC50 values obtained were compared with those obtained for the inhibition of human platelet COX activity, a COX-1 selective assay. Classical non-steroidal anti-inflammatory drugs (NSAIDs) inhibited both enzymes with varying potencies but only the three compounds previously shown to be selective COX-2 inhibitors (SC-58125, NS-398 and nimesulide) showed higher potency towards the COX of PMA-treated HUV-EC-C. 8. Overall, it appears that the stimulation of the HUV-EC-C line with PMA selectively induces the COX-2 isoenzyme. This appears to be a suitable model for the study of the physiology and pharmacology of this important isoenzyme, with a permanent endothelial cell line of human origin.