Gut 1993; 34:742-747

Enhanced gastric mucosal leukotriene B4 synthesis inpatients taking non-steroidal anti-inflammatorydrugs

N Hudson, M Balsitis, S Everitt, C J Hawkey

AbstractThe effects of longstanding non-steroidal anti-inflammatory drug (NSAID) treatment ongastric mucosal synthesis of leukotriene B4(LTB4), leukotriene C4 (LTC4), and prosta-glandin E2 (PGE2) was studied. Gastric antralbiopsies in 65 patients with arthritis takingNSAIDs and 23 control patients were takenand eicosanoid concentrations, stimulated byvortex mixing or calcium ionophore, weremeasured by radioimmunoassay. Mediangastric mucosal synthesis of LTB4 wasincreased in patients taking NSAIDs com-pared with non-users: (0 9 (0 2-2 5) pg/mg v 0(0-0.6) pg/mg (p<0001)). These differencespersisted when subgroups of patients wereanalysed according to Helicobacter pyloncolonisation or degree of mucosal injury.Synthesis of LTB4 was strongly associatedwith the presence of type C (chemical) gastri-tis. Increased synthesis of LTC4 was associ-ated with Helicobacter pylori colonisation butnot NSAID use. Synthesis of PGE2 wasdecreased in patients taking NSAIDs com-pared with control patients (p<0001).Enhanced gastric mucosal synthesis of LTB4in patients taking NSAIDs may represent aprimary effect of these drugs and could beimplicated in the pathogenesis of gastritis andulceration associated with NSAIDs.(Gut 1993; 34: 742-747)

Department ofMedicine, UniversityHospital, NottinghamN HudsonM BalsitisS EverittC J HawkeyCorrespondence to:Professor C J Hawkey,Department of Medicine,University Hospital,Nottingham NG7 2UH.Accepted for publication15 October 1992

Non-steroidal anti-inflammatory drugs(NSAIDs) are associated with gastric mucosalinjury that may result in peptic ulceration, uppergastrointestinal haemorrhage, and perforation.'Mucosal injury is often ascribed to the wellestablished ability of NSAIDs to inhibit synthe-sis ofprostaglandins, as prostaglandins stimulatemucosal defence mechanisms such as secretionof mucus and bicarbonate and enhance mucosalblood flow.23 Profound inhibition of synthesisof prostaglandins can occur in the absence ofmucosal injury,4 and depletion of mucosalprostaglandins may be only one of several factorsresponsible for the pathogenesis of injury relatedto NSAIDs.

Theoretically, as a result of substrate diversionof arachidonic acid, inhibition of cyclo-oxygenase by NSAIDs may lead to the increasedformation of the leukotriene series through the5-lipoxygenase pathway. Leukotrienes are

known proinflammatory mediators and leuko-triene B4 (LTB4) is a potent chemoattractant ofpolymorphonuclear cells and causes degranula-tion and release of lysosomal enzymes,56 whichcould play an important part in amplifying the

inflammatory response to NSAIDs. Similarlyleukotriene C4 (LTC4) could mediate gastricmucosal damage both by its vasoconstrictiveactions and its effects on vascular permeabilitypromoting vascular stasis and subsequent reduc-tion in tissue perfusion.78 Animal studies haveshown a correlation between the gastric mucosalinjury induced by ethanol or acid and increasedsynthesis of leukotrienes.8 `' Some authors haveshown that lipoxygenase inhibitors are protec-tive in such protocols,"2-14 but more recently thishas been questioned.'5 16 Where mucosal protec-tion has been shown it does not correlate wellwith potency of inhibition of 5-lipoxygenase andcould be due to another property such as oxygenradical scavenging. Enhancement of gastro-intestinal synthesis of leukotrienes by NSAIDsin humans has not hitherto been shown andexperimental evidence is conflicting; indo-methacin has been reported to enhance synthesisof LTB4,'7 have no effect on synthesis ofLTB4,'8and inhibit synthesis of LTC4, albeit to a lesserextent than its effects on prostaglandins'9 in therat stomach.To clarify a possible role for synthesis of

leukotrienes in damage caused by NSAIDs weinvestigated the effects of long term NSAIDtreatment on gastric mucosal LTB4, LTC4, andprostaglandin E2 (PGE2) concentrations inpatients with arthritis compared with controlsubjects not taking NSAIDs. We correlatedthese findings with endoscopic mucosal damage,the presence or absence of Helicobacter pylori,and the degree of histological gastritis.

Patients and methodsSixty five patients with rheumatoid arthritis(n=57) or osteoarthritis (n=7) on NSAIDs for>3 months (mean (SD): 4-7 (3-1) years) wererecruited from a rheumatology clinic to undergoscreening by upper gastrointestinal endoscopybefore entry into a therapeutic trial, approved bythe hospital ethics committee. Patients were notincluded in the study if they had undergoneprevious gastric surgery or if they were receivingcytotoxic drugs or >5 mg/day prednisolone.Patients receiving other second line agents -namely, gold, penicillamine, sulphasalazine, orhydroxychloroquine - were included in thestudy. Those taking H2 receptor antagonistsstopped this medication at least one week beforeendoscopy. The control subjects were 23patients concurrently undergoing endoscopy fordyspeptic symptoms. The control subjects hadreceived neither aspirin nor NSAIDs in the threemonths before study.

Informed consent was obtained before endo-

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Enhanced gastric mucosal leukotriene B4 synthesis in patients taking non-steroidal anti-inflammatory drugs

scopy. At endoscopy, a visual assessment andvideo recordings were made of ulceration andgastropathy (Olympus GIF XV10). Nine antralgastric biopsies were taken 3-4 cm from thepyloric ring. One sample was placed in a CLOtest (a gel based rapid urease test)20 for assess-ment of Helicobacter pylon colonisation (apositive result was denoted by a colour change atfour hours). Two samples were immediatelyfixed in 10% formalin for histological assess-ment. Paraffin wax sections were cut and stainedby both haematoxylin and eosin and giemsa andassessed for evidence of gastritis and Helicobacterpylori organisms. Gastritis was defined accordingto the system proposed by Wyatt and Dixon.2'Type C (chemical) gastritis was characterisedby the presence of foveolar hyperplasia andtortuosity, vasodilatation, and congestion with apaucity of inflammatory cells in the laminapropria layer. Type B gastritis (chronic activegastritis) was characterised by an increase ininflammatory cells (lymphocytes, plasma cells,histiocytes) in the lamina propria of the mucosaand polymorphonuclear neutrophils infiltratingthe epithelium. Histopathology assessmentswere made without knowledge of the endoscopicor biochemical findings.The remaining six biopsy samples were

divided into pairs and washed in 1 ml of Trissaline buffer. Each pair was then vortex mixedfor six seconds and centrifuged for 10 seconds,the supernatant stored, and the procedurerepeated. A further 300 tl of Tris saline bufferwas then added. Synthesis of eicosanoids wasstimulated by vortex mixing for a furtherminute. After centrifiguration for 10 seconds thesupernatant was removed and stored at -70°Cuntil assayed (within three months.)22 In a sub-group of patients further biopsy samples werestimulated by calcium ionophore A23187 for aperiod of 20 minutes, as described elsewhere,23before the supernatant was stored. Immuno-reactive LTB4, LTC4, and PGE2 were measuredby radioimmunoassay and results were expres-sed as pg/mg wet weight of gastric biopsysample. Chemicals for radioimmunoassay werefrom Amersham International except PGE2antiserum, which was from Sigma ChemicalCompany.

VALIDATION OF ASSAYSIntra-assay coefficients of variation were 3-8%for LTB4, 3-9% for LTC4, and 2-5% for PGE2(n= 10). Interassay coefficients of variation were

TABLE I Patient characteristics and Helicobacter pyloricolonisation in patients on NSAID treatment and controlsubjects

NSAIDs Controls(n=65) (n=23)

Male:female 27:38 11:12Mean (SEM) age (y) 58 0(1-3) 58-9 (2 4)Smokers (%) 16(25) 8 (30)Mean (SD) duration ofNSAID

treatment (y) 4-7 (3-1) -

Helicobacterpylori colonisation (%) 25 (38) 12 (52)Endoscopic injury:

Ulcer 9 5Erosions 17 5Haemorrhages 16 0Normal 23 13

7-6% for LTB4, 5-3% for LTC4, and 12 4% forPGE2. Experiments with exogenous compoundsshowed a good correlation between amountsadded and amounts measured. Overall correla-tions for measured v added were 0-998 for LTB4,0-988 for LTC4, and 0 990 for PGE2 (n=6).Cross reactivity and sensitivity of all threeradioimmunoassays has been previously des-cribed.2223 The lower limits of detection byradioimmunoassay were: LTB4 0-2 pg, LTC41 pg, and PGE2 2 pg.

STATISTICAL METHODSThe influence of age, sex, smoking, use ofprednisolone or second line treatment, Helico-bacter pyloni colonisation, and NSAID use oneach of the dependent variables was analysed bystepwise multivariate regression analysis withthe SPSS programme (statistical package forsocial sciences). Non-parametric methods wereused with significance determined at the 5%level. The Mann-Whitney U test was used forpairwise comparisons where the influence ofindependent variables was identified as signifi-cant by the multivariate analysis. Results areexpressed as medians (interquartile ranges).

Results

PATIENTSOverall 65 patients taking NSAIDs for arthritisand 23 control non-users were analysed. Table Ishows characteristics of sex, age, smoking, andduration of NSAID use. Of 65 patients takingNSAIDs nine had endoscopic evidence ofulcera-tion (six gastric, three duodenal), as defined by amucosal lesion greater than 3 mm in diameterwith definite depth. Seventeen had gastricerosions, mainly confined to the antrum. Sixteenpatients had minor gastropathy consisting ofsubmucosal or petechiae haemorrhage and theremaining 23 patients had endoscopically normalmucosa. Twenty five of the patients takingNSAIDs were positive for Helicobacter pylori asdetermined by histology andCLO test. Ofthe 23control subjects who did not use NSAIDs ulcera-tion was present in five (three gastric, twoduodenal), five had erosions, and 14 had anendoscopically normal mucosa. Twelve of thesecontrols were positive for Helicobacter pylori.Twenty (31%) patients taking NSAIDs had ahistologically normal antral gastric mucosa.Twenty (31%) patients had a type C (chemical)gastritis, and the remaining 25 (38%) had a typeB (active) gastritis. Helicobacter organisms wereidentified in all but two patients with type Bgastritis and in two patients with type C gastritis.(Table II).

TABLE II Relation ofhistology to NSAID use andHelicobacter pylori colonisation

NSAID ControlsHelicobacter pylori Helicobacter pylori

+ - + -

Normal 0 20 0 12TypeCgastritis 2 18 0 0Type B gastritis 23 2 12 0

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Hudson, Balsitis, Everitt, Hawkey

p < 0 001

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Figure 1: Gastric mucosalsynthesis ofleukotriene B4(L TB4) in 65 patients witharthritis on longstandingNSAID treatment comparedwisth 23 controls. Mediansdenoted by bar lines.

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EFFECT OF NSAID USE ON SYNTHESIS OFEICOSANOIDS

Leukotriene C4By contrast with LTB4, colonisation by Helico-bacter pylon, but not NSAID use was associatedwith increased vortex stimulated LTC4 syn-thesis. Among NSAID users those with Helico-bacter pylori colonisation synthesised 3-1(1-5-4 0) pg/mg (n=23) compared with 3-2(0 6-5 3) pg/mg (n= 12) in non-users. In thosenot colonised with the organism synthesis ofLTC4 was 2-0 (1-2-2-8) pg/mg (n=32) inNSAID users and 2-2 (0-2 6) pg/mg (n=11) innon-users. The values for synthesis of LTC4 inthose colonised with Helicobacter pylon weresignificantly higher (p<004) than in those notcolonised (Fig 2).

Prostaglandin E2As found in previous studies patients takingNSAIDs synthesised less PGE2 than those nottaking these drugs. Median gastric mucosalsynthesis of PGE2 stimulated by vortex mixingwas 16&2 (8-0-403) pg/mg (n=65) in NSAIDusers and 51-4 (22 3-75 0) pg/mg (n=23) in non-users (p<0001). Concentrations of PGE2 werenot measured in samples stimulated by calciumionophore because limited material was avail-able.

Leukotriene B4Treatment with NSAIDs, gastritis, and use ofsecond line treatment were the only independentvariables identified as exerting a significantinfluence on synthesis of LTB4 in the multi-variate analysis.Median gastric mucosal synthesis of LTB4 in

patients taking NSAIDs as determined by vortexmixing was 0 9 (0-2-2-5) pg/mg (n=65). Thiswas significantly higher than the value of 0(0-06) pg/mg seen in controls (n=23, p<0001,Fig 1). Similarly when synthesis of LTB4 wasstimulated by calcium ionophore there was also asignificant increase in LTB4 concentrationsfound in NSAID users (1 5 (0 3-2 6) pg/mg(n=60)) compared with non-users (0 (0-01)pg/mg (n= 14)) (p<0 01).The increase in synthesis of LTB4 seen in

patients taking NSAIDs remained significantwhen the subgroups who were Helicobacter pyloripositive or negative were analysed separately.Among those patients who were Helicobacterpylori positive NSAID treatment was associatedwith synthesis of LTB4 of 1-2 (0-4-2-6) pg/mg(n=25) compared with 0 (0-0 4) pg/mg in non-users (n=12, p<0005). In those who wereHelicobacter pylori negative NSAID use wasassociated with LTB4 synthesis of 0-8 (0-0-2 2)pg/mg (n=40) compared with 0 (>-I O)pg/mg innon-users (n= 11) (p<0005). Within the twogroups, NSAID users and non-users, there wereno significant differences between synthesis ofLTB4 in patients colonised or not colonised withthe organism.A similar pattern of results of enhanced

synthesis of LTB4 with NSAID use across all

CORRELATION OF SYNTHESIS OF LEUKOTRIENESWITH ENDOSCOPIC INJURYAlthough there was a trend ofhigher synthesis of

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Figure 2: Influence ofHelicobacter pylori (HP) colonisationon gastric mucosal synthesis ofleukotriene C4 (L TC4) in 55patients with arthritis on longstanding NSAID treatment and23 controls. Medians denoted by bar lines.

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Enhanced gastric mucosal leukotriene B4 synthesis in patients taking non-steroidal anti-inflammatory drugs

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2-Figure 3: Influence ofendoscopic mucosal injury ongastric mucosal leukotrieneB4 (L TB4) in 65 patientswith arthritis onlongstanding NSAIDtreatment. Medians denotedby bar lines.

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LTB4 in those NSAID subjects with endoscopicevidence of more severe mucosal injury this didnot reach statistical significance. Patients withulceration or erosions synthesised 2-2 (0-1-3-0)pg/mg of LTB4. In comparison those withonly submucosal haemorrhages synthesised 10(O-4-2' 1) pg/mg and those with an endoscopic-ally normal mucosa synthesised 07 (00-1 7)pg/mg (p= 0 1 1, Fig 3). By contrast no such trendwas seen with synthesis of LTC4. In NSAIDusers with ulcers or erosions synthesis of LTC4was 1 9 (12-3 1) pg/mg LTC4 (n=22) comparedwith 2-8 (1-2-3-7) pg/mg (n=20) in those with anormal mucosa (p=0 4).

CORRELATION OF SYNTHESIS OF LEUKOTRIENEWITH GASTRITISSynthesis ofLTB4 was also measured in patientsaccording to the histological state of antralbiopsies. All controls with type B (active)gastritis were Helicobacter pyloni positive withLTB4 values of 0 (0 0-0 4) pg/mg, whereas thosewho were Helicobacter pylon negative all had anormal histological appearance and values of 0(0-0-1 0) pg/mg. In patients taking NSAIDsthose with type C (chemical) gastritis synthesisedLTD4 concentrations of 2-2 (0-4-3 0) pg/mg,significantly higher than 0-6 (0 0-0 9) pg/mg inpatients with a normal mucosa (p<0008).Patients with type B gastritis synthesised 1-0(0 4-2 6) pg/mg, again significantly higher thanthose with a normal mucosa (p<002, Fig 4)..By contrast there were no significant differ-

ences in synthesis of LTC4 in NSAID usersbetween those with type C gastritis (2-3 (1 -5-3 0)pg/mg) compared with those with normal mucosa(1 8 (1 -2-2-8) pg/mg) although enhanced syn-thesis in those with type B gastritis (3-2 ( 5-4 0)pg/mg) reflected the higher concentrations seenin patients colonised with Helicobacter pylori(p<0 02).

CORRELATION OF SYNTHESIS OF LEUKOTRIENESWITH SECOND LINE TREATMENTThe use of second line drugs in the managementof rheumatoid arthritis was also identified asan independent variable that significantlyinfluenced leukotriene concentrations. Thus inpatients taking NSAIDs synthesis of LTB4 was2-2 (0 8-4 5) pg/mg (n=24) in those takingsecond line treatment compared with 0-8 (0 0-2 3) pg/mg (n=41) in patients not on these drugs(p<0006). In patients taking NSAIDs but nottaking second line treatment synthesis of LTB4was still significantly higher than in controls(p<0005). Use of prednisolone, however, didnot influence synthesis of LTB4. Synthesis ofLTC4 was also unrelated to second line treatment(2-3 (1L4-3-5) v 2-8 (1L6-3-9) pg/mg).

DiscussionIn this paper we have shown that longstandingNSAID treatment in patients with arthritis isassociated with increased gastric mucosalsynthesis ofLTB4 compared with controls. Thisincrease was seen whether synthesis was stimu-lated by vortex mixing or by calcium ionophoreand persisted across subgroups of patients withor without mucosal damage and with or withoutHelicobacter pylori colonisation. Our study alsoshows that NSAID treatment results in reducedgastric mucosal synthesis of PGE2, as is wellknown,24 but no significant changes in synthesisof LTC4 related to NSAIDs.Although age and sex did not influence the

results, enhanced synthesis of lipoxygenase pro-ducts has been reported in the synovial fluid and

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Figure 4: Relation between gastritis as assessed histologicallyand gastric mucosal synthesis ofleukotriene B4 (L TB4) in 65patients with arthritis on longstanding NSAID treatment.Medians denoted by bar lines.

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Hudson, Balsitis, Everitt, Hawkey

tissue of patients with rheumatoid arthritis orspondyloarthritis25 and it is possible that this wasa confounding variable. As most patients withrheumatoid arthritis take NSAIDs it may bedifficult to discriminate between these factors.We also found an independent correlationbetween second line treatment and increasedLTB4 concentrations that may either reflect apharmacological effect or a correlation withdisease activity. The confounding use of secondline drugs does not explain the increased syn-thesis of LTB4 seen in patients taking NSAIDsoverall. Dexamethasone has also been reportedto suppress leukotriene activity in vitro"although we found no effect of low doseprednisolone in this study. Similarly, althoughsmoking is known to suppress gastric mucosalcyclo-oxygenase activity26 27 we found no correla-tion with synthesis of LTB4.

Accurate assessment of mucosal eicosanoidconcentrations is notoriously difficult. Biopsytrauma is itself a stimulus to the synthesis ofeicosanoids, but tissue fragments used for shortincubation periods overcome the problems oftissue viability and both mechanical andchemical stimulation of synthesis of leukotrieneare well established methods ofgeneration understandardised conditions.28 29 Extraction pro-cedures were the same in patients and controlsand values can be regarded as an index of thecapacity of the mucosa to synthesis eicosanoids.

Previous studies in humans have shown thatsynthesis of leukotrienes correlates with gastro-duodenal mucosal injury. In patients withduodenal ulcers gastric and duodenal mucosalsynthesis of LTB4 and synthesis of LTC4 wereraised compared with controls and were signific-antly reduced after the ulcer healed.30 Similarlywe found a trend towards higher synthesis ofLTB4 in patients with endoscopic evidence ofinjury. Increases of both LTB4 and LTC4 havealso been reported with gastritis associated withHelicobacter pylori.3'32 We also found enhancedsynthesis of LTC4 associated with Helicobacterpylori colonisation. There was, however, nosignificant enhancement ofLTB4 associated withHelicobacter pylorn colonisation among patientstaking NSAIDs. Values were too low to judge.whether there was any effect associated withHelicobacter pylo7i colonisation in controls.Our study does not identify the mechanism by

which NSAID treatment leads to enhancedsynthesis of LTB4. Although the possibility thatinhibition of cyclo-oxygenase results in diver-sion of the substrate arachidonic acid down5-lipoxygenase pathways has been much dis-cussed it has been difficult to confirm. In vitroconcentrations of indomethacin that completelyblock cyclo-oxygenase seem to increase produc-tion of 5-hydroperoxy-eicosatetraenoic acid(5-HETE), another lipoxygenase product inleukocytes.33 Peskar, however, found that highdoses of indomethacin actually inhibited syn-thesis of LTC4 in rat gastric mucosa.'9 As thisinhibition was less than the accompanyinginhibition of PGE2 it was possible to argue thatsome substrate diversion might have occurred,although weak inhibition of the 5-lipoxygenaseenzyme by indomethacin seems a simpler andmore plausible explanation. Clayton and col-

leagues have reported findings in isolated ratstomach antrum in vitro where indomethacinenhanced the release of LTB4 as well as LTC4,LTD4, and LTE4 in the presence of calciumionophore A23187,'7 but other studies byWallace et al have failed to show any increasein gastric mucosal synthesis of LTB4 after acuteadministration of indomethacin.'8 We haveshown enhanced LTB4 with no significant effecton LTC4 in patients on NSAID treatment. Thisraises the possibility that a mechanism other thansubstrate diversion is involved or that the variouseicosanoids arise from different cellular sourcesand substrate diversion only occurred in a cellcapable of synthesising LTB4 but not LTC4.Synthesis of LTB4 by gastric mucosal epithelialcells has been reported34 and it is possible thatthese are an important source of the increasedconcentrations we have seen in patients takingNSAIDs.An alternative explanation of the raised

synthesis of LTB4 is that it is a secondaryconsequence of gastritis or injury related toNSAIDs. The multivariate analysis showedsignificantly increased synthesis of LTB4 inNSAID users, however, compared with controlsindependent of the degree or type of the accom-panying gastritis. Again there was a dissociationbetween LTB4 and LTC4 with significantincreases in LTB4 being particularly associatedwith type C gastritis and increases in LTC4 withtype B gastritis associated with Helicobacterpylon. Increases in LTC4 could be secondary tothe invasion of inflammatory cells that accom-panies Helicobacter pylon colonisation and thatcharacterises type B gastritis. By contrast type Cgastritis is characterised by foveolar hyperplasiaand elongation and tortuosity of vessels togetherwith oedema, vasodilatation, and congestionwith a paucity of inflammatory cells. Our dataconfirm the previous reports of an associationwith NSAID use.3537 The paucity of inflamma-tory cells in the lamina propria that is usuallyseen with this type of gastritis makes it difficultto argue that the increased synthesis derives frominflammatory cells. If gastric mucosal epithelialcells are the main source of LTB4,34 enhancedsynthesis could simply be a consequence ofthe hyperplastic epithelium characteristic ofchemical gastritis. Conversely, these hyper-plastic features could be taken to imply epithelialremodelling possibly under the influence of achemical mediator. Our data raise the possibilitythat LTB4 is a candidate for this role as it isplausible that LTB4 contributes to the vascularchanges and oedema that characterise type Cgastritis.

If NSAIDs directly enhance leukotrienesynthesis this may also contribute to mucosalinjury. Whereas removal of prostaglandindependent mucosal defence mechanismsremains a central mechanism in the developmentofgastric mucosal injury related to NSAIDs, thiscould be enhanced by increased synthesis ofleukotriene, as LTB4 attracts and activates poly-morphonuclear leucocytes36 and peptidoleuko-trienes are potent vasoconstrictors capable ofincreasing vascular permeability and causingmicrocirculatory stasis.78 Establishment of acausal role for leukotrienes in the pathogenesis of

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Enhanced gastric mucosal leukotriene B4 synthesis in patients taking non-steroidal anti-inflammatory drugs 747

mucosal damage has, however, remainedelusive. Studies in rats have shown a correlationbetween gastric damage induced by ethanol andother agents and endogenous LTC4 concentra-tions,8 9 1' and infusion of peptidoleukotrienescan potentiate ethanol mediated gastric damage.'0Although some studies have shown lipoxygenaseinhibitors to be protective,'2-'4 more recentstudies have not.'"6 Dietary replacement ofarachidonic acid by eicosapentaenoic acid resultsin an enhanced resistance to ethanol inducedgastric damage. This might be due to the accom-panying reduction in synthesis of the 4 seriesleukotrienes.38More recent reports suggest that acute indo-

methacin induced gastric mucosal injury in ratsis accompanied by neutrophil adherence tomesenteric microvascular endothelium and thatthe severity of gastric injury can be greatlyreduced by prior neutrophil depletion withneutrophil antibodies.26 Moreover neutrophiladhesion to the endothelium seems to correlatewith increased LTB4 concentrations andadhesion is prevented by inhibitors of thesynthesis of leukotrienes.39 This finding suggestsa direct interaction between NSAIDs, synthesisof LTB4, and mechanisms of subsequentmucosal injury. Measurement of gastric mucosalleukotrienes in humans after acute dosing withindomethacin and other NSAIDs and investi-gation of the effects of other inhibitors of5 lipoxygenase will be necessary to define moreprecisely the role of leukotrienes in mucosalinjury related to NSAIDs.

In conclusion, we have shown that enhancedin vitro synthesis. of LTB4 by human gastricmucosa occurs with NSAID use and is stronglyassociated with type C gastritis. There arereasons to believe that the association may be aprimary affect of drug treatment, which couldmediate some of the pathological changes associ-ated with NSAID use rather than a secondaryconsequence of these changes.

Part of this work was presented at the American GastroenterologyAssociation Meeting, New Orleans, USA, in May 1991.

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2 Vane JR. Inhibition ofprostaglandin synthesis as a mechanismof action of aspirin like drugs. Nature New Biol 1971; 231:232-5.

3 Hawkey CJ, Rampton DS. Prostaglandins and the gastro-intestinal mucosa: are they important in its function,disease, or treatment. Gastroenterology 1985; 89: 1162-88.

4 Ligumsky M, Golanska EM, Hansen DG, Kauffman GL.Aspirin can inhibit gastric mucosal cyclo-oxygenase withoutcausing lesions in rats. Gastroenterology 1983; 84: 756-61.

5 Ford-Hutchinson AW, Bray MA, Doig MW, Shipley ME,Smith MJH. Leukotriene B: a potent chemokinetic andaggregating substance released from polymophonuclearleukocytes. Nature 1980; 286: 264-5.

6 Bokoch GM, Reed PW. Effect of various lipooxygenasemetabolites of arachidonic acid on degranulation of poly-morphonuclear leukocytes.JBiolChem 1981; 256: 5317-20.

7 Whittde BJR, Oren-Walnan N, Guth PH. Gastric vasocon-strictor actions of leukotriene C4, PGF2, and thromboxanemimetic U-46619 on rat submucosal microcirculation invivo. AmjPhysiol 1985; 248: G580-6.

8 Pihan G, Rogers C, Szabo S. Vascular injury in acute mucosaldamage. Mediatory role of leukotrienes. Dig Dis Sci 1988;33: 625-32.

9 Peskar BM, Hoppe U, Lange K, Peskar BA. Effects of nonsteroidal anti-inflammatory drugs on rat gastric mucosalleukotriene C4, and prostanoid release: relation to ethanolinduced injury. BrJ' Pharmnacol 1988; 93: 937-43.

10 Wallace JL, McKnight GW, Keenan CM, Byles NIA,MacNaughton WK. Effects of leukotrienes on susceptibilityof the rat stomach to damage and investigation of themechanisms of action. Gastroenterology 1990; 98: 1178-86.

11 Wallace JL, MacNaughton WK. Gastrointestinal damage

induced by platelet-activating factor: role ot leukotrienes.EurJ Pharmacol 1988; 151: 43-50.

12 Konturek SJ, Brzozowski T, Drozdowicz D, Beck G. Role ofLeukotrienes in acute gastric lesions induced by ethanol,taurocholate, aspirin, platelet activating factor and stress inrats. Dig Dis Sci 1988; 33: 806-13.

13 Yonei Y, Guth P. Lipoxygenase metabolites in the rat gastricmicrovascular response to intragastric ethanol. Gastro-enterology 1989; 97: 304-12.

14 Wallace JL, Whittle BJR. Role ofprostanoids in the protectiveactions of BW755C on the gastric mucosa. Eurj Pharmacol1985; 115: 45-52.

15 Boughton-Smith NK, Whittle BJR. Failure of the inhibitionof rat gastric mucosal 5 lipoxygenase by a novel ace-thydroxamic acid to prevent ethanol induced gastricdamage. BrJPharmacol 1988; 95: 155-62.

16 Wallace JL, Beck PL, Morris GP. Is there a role forleukotrienes as mediators ofethanol induced gastric damage.AmJ Physiol 1988; 254: G117-23.

17 Clayton NM, Trevethick MA, Strong P. Eicosanoid releasefrom the antral and corpus regions of the rat stomach. BrJPharmacol 1991; 102: 362P.

18 Wallace JL, Keenan CM, Granger DN. Gastric ulcerationinduced by non steroidal anti-inflammatory drugs is aneutrophil dependent process. Am J Physiol 1990; 259:G462-7.

19 Peskar BM. Role of leukotriene C4 in mucosal damage causedby necrotising agents and indomethacin in the rat stomach.Gastroenterology 1991; 100: 619-26.

20 Marshall BJ, Warren RJ, Francis GJ, Langton SR, GoodwinCS, Blincow ED. Rapid urease test in the management ofCampylobacter pyloridis-associated gastritis. Am JGastroenterol 1987; 82: 200-10.

21 Wyatt JI, Dixon MF. Chronic gastritis: a pathogeneticapproach.J Pathol 1988; 154: 113-24.

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anti-inflammatory drugs.synthesis in patients taking non-steroidal Enhanced gastric mucosal leukotriene B4

N Hudson, M Balsitis, S Everitt and C J Hawkey

doi: 10.1136/gut.34.6.7421993 34: 742-747 Gut 

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