Predictors of gastroduodenal erosions in patients taking low-dose aspirin

Background  Gastroduodenal ulcers are common in patients taking low-dose aspirin. However, the factors predisposing to mucosal erosions, the precursor lesions, are not well known.
Aims  To examine the potential risk factors for the development of erosions in patients chronically taking low-dose aspirin.
Methods  Patients included were taking aspirin 75–325 mg daily for >28 days. Exclusion criteria included use of nonsteroidal anti-inflammatory and ulcer-healing drugs. Demographic data were collected at baseline, prior to endoscopy to determine the frequency and number of erosions and Helicobacter pylori status. In those without ulcer or other exclusions, endoscopy was repeated at 3 months.
Results  Fewer patients had gastric erosions if they were H. pylori +ve (48.5% vs. 66.4% in H. pylori −ve patients at baseline, P  = 0.17; 40.0% vs. 64.1% at 3 months, P  = 0.029). If gastric erosions were present, they were also less numerous in H. pylori +ve patients (3.61 ± 0.83 vs. 4.90 ± 0.53 at baseline, P  = 0.026; 2.17 ± 0.68 vs. 5.68 ± 0.86 at 3 months, P  = 0.029). There was a trend (0.1 >  P  > 0.05) for more gastric erosions in those taking >100 mg/day aspirin. Males had more duodenal erosions at baseline (25.2% vs. 7.5%, P  = 0.016). Patient age did not affect the presence or number of erosions. H. Pylori was not significantly associated with duodenal erosion numbers.
Conclusions  Helicobacter pylori infection may partially protect against low-dose aspirin-induced gastric erosions; damage to the stomach appears weakly dose-related; and older age does not increase the risk of erosions.     

Effect of cyclooxygenase-2 inhibition on human Helicobacter pylori gastritis: mechanisms underlying gastrointestinal safety and implications for cancer chemoprevention

Cyclooxygenase (COX)-2 expression and prostaglandin production is increased by Helicobacter pylori infection. Non-selective COX inhibitors reduce prostaglandins and mucosal proliferation in infected mucosa and may reduce gastric cancer risk, but ulceration precludes their use. COX-2 inhibitors cause fewer ulcers and may be chemopreventive. Physiological studies of COX-2 inhibitors in humans with H. pylori infection have not been performed. AIM: To study the impact of COX-2 specific inhibition on gastric prostaglandin levels, H. pylori gastritis and proliferation. METHODS: Twenty infected (eight males, 12 females; age 38 +/- 1.8) and six uninfected (four males, two females; age 36 +/- 3.5) healthy volunteers received rofecoxib 25 mg daily for 14 days. Endoscopic biopsies were evaluated for prostaglandin E2 (PGE2) content, gastritis and proliferation. RESULTS: Before drug therapy, compared to uninfected, H. pylori-infected subjects had significantly higher: (a) gastric mucosal PGE2 (pg/mg tissue) in the gastric body and antrum, (b) H. pylori score in body and antrum and (c) mid-gland proliferation index in antrum and body. The COX-2 inhibitor did not significantly affect PGE2 levels, gastritis scores or proliferation indices in the body or antrum in the H. pylori-positive or -negative subjects. CONCLUSION: The predominant source of increased gastric PGE2 in H. pylori infection appears to be COX-1-derived. In non-ulcerated H. pylori gastritis, COX-2 inhibition does not affect cellular proliferation. Rofecoxib's lack of effect on gastric prostaglandin levels and proliferation in H. pylori-infected mucosa may explain the absence of an increased ulcer risk among COX-2 inhibitor users with H. pylori infection. The lack of significant effect on intermediate biomarkers raises uncertainty regarding the potential of specific COX-2 inhibitors for chemoprevention of gastric cancer.     

Low-dose misoprostol for the prevention of low-dose aspirin-induced gastroduodenal injury

INTRODUCTION: The harmful effects of non-steroidal anti-inflammatory drugs (NSAIDs) on the gastric mucosa and the prophylactic effects of misoprostol are both dose-dependent. AIM: To investigate whether a low-dose of misoprostol is sufficient to prevent gastric mucosal injury caused by low-dose aspirin. METHODS: We conducted a double-blind placebo controlled parallel group endoscopic study in 32 evaluable volunteers. The main outcome measure was erosive injury (ulcers and superficial erosions) in the gastric mucosa over 28 days. RESULTS: Most subjects developed erosions on aspirin 300 mg daily. This was significantly reduced by misoprostol 100 microg daily. (Odds ratio 0.18, 95% CI: 0.07-0.48). There were no drug-related or gastrointestinal adverse events in subjects receiving misoprostol. CONCLUSION: Misoprostol 100 microg daily can prevent low-dose aspirin induced gastric mucosal injury without causing identifiable adverse effects.     

COX-2 inhibitors vs. NSAIDs in gastrointestinal damage and prevention

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit production of protective gastric mucosal prostaglandins and also have a direct topical irritant effect. In some patients this results in dyspepsia and development of gastroduodenal erosions and ulceration. The risk of ulcer complications, such as bleeding, perforation and death is increased approximately 4-fold in NSAID users. Patients at high risk of ulcer complications include the elderly, those taking anticoagulants, steroids and aspirin, those with a previous history of peptic ulceration and patients with concomitant serious medical problems. The interaction of NSAIDs with Helicobacter pylori (the major cause of peptic ulceration in non-NSAID users) is controversial and some studies suggest that H. pylori infection may even protect against NSAID-induced ulceration. Selective inhibitors of the inducible cyclooxygenase-2 (COX-2) enzyme spare COX-1 in the gastric mucosa and, hence, do not inhibit production of mucosal prostaglandins. COX-2-selective inhibitors are associated with a significant reduction in gastroduodenal damage compared with traditional NSAIDs. Proton pump inhibitors (PPI) are probably the best agents for healing and prevention of NSAID-induced ulcers. Preliminary studies suggest that COX-2 selective inhibitors, like traditional NSAIDs, may prevent lower gastrointestinal cancer. Further studies are needed but they may be useful in individuals at high risk of certain types of lower gastrointestinal malignancy with increased gastrointestinal tolerability and safety.     

Treatment and prevention of aspirin-induced gastroduodenal ulcers and gastrointestinal bleeding

Aspirin use is associated with gastroduodenal mucosal damage and increased risk of upper gastrointestinal (GI) bleeding. Many aspirin users should receive prophylactic treatment since they often have several risk factors for upper GI complications. The best therapeutic approach for reducing GI toxicity in low-dose aspirin users is still ill-defined as only a few studies have focused on this problem. Omeprazole appears to be very effective in reducing both acute gastroduodenal mucosal damage and upper GI bleeding in the high-risk patient taking low-dose aspirin, but data with other anti-ulcer agents are lacking (misoprostol) or inconsistent (ranitidine) at present. The role of Helicobacter pylori is controversial in NSAID users, but there is now wide agreement that H. pylori infection increases mucosal damage and the risk of upper GI bleeding in low-dose aspirin users.     

Protection of human gastric mucosa against aspirin—enteric coating or dose reduction?

BACKGROUND: Aspirin is widely used for cardiovascular prophylaxis. AIM: To compare the effectiveness of two widely-used strategies-dose reduction and enteric coating-for the minimization of gastric mucosal injury or toxicity. METHODS: Twelve healthy volunteers were studied. On four separate occasions each received, under blinded conditions, five daily doses of plain aspirin 300 mg, plain aspirin 75 mg, enteric-coated aspirin 300 mg or placebo. Ex vivo prostaglandin E2 synthesis was stimulated by the vortex mixing of gastric mucosal biopsies in Tris saline and measured by radioimmunoassay. Mucosal injury was quantified both by counting erosions and with a visual analogue scale. RESULTS: All three preparations reduced prostaglandin E2 synthesis by day five, by (median) 84% for plain aspirin 300 mg, by 80% for enteric coated aspirin 300 mg and by 63% for plain aspirin 75 mg. There was little mucosal injury prior to the start of each dose and period and no significant change with placebo. Plain aspirin caused a dose-dependent mucosal injury, with two (median, IQR 0-7) gastric erosions after five days of plain aspirin 75 mg, and 18 (2-26) after five days of plain aspirin 300 mg. With enteric-coated aspirin 300 mg there were 0 (0-1) gastric erosions (P = 0.003 compared to plain aspirin 300 mg P = 0.11, compared to plain aspirin 75 mg). CONCLUSION: Enteric coated aspirin reduces acute gastric mucosal injury to placebo levels, despite its inhibition of prostaglandin synthesis. Enteric coating is an appropriate strategy for the prevention of gastric mucosal damage induced by low-dose aspirin, which warrants systematic clinical evaluation.     

Treatment and prevention of aspirin-induced gastroduodenal ulcers and gastrointestinal bleeding

Aspirin use is associated with gastroduodenal mucosal damage and increased risk of upper gastrointestinal (GI) bleeding. Many aspirin users should receive prophylactic treatment since they often have several risk factors for upper GI complications. The best therapeutic approach for reducing GI toxicity in low-dose aspirin users is still ill-defined as only a few studies have focused on this problem. Omeprazole appears to be very effective in reducing both acute gastroduodenal mucosal damage and upper GI bleeding in the high-risk patient taking low-dose aspirin, but data with other anti-ulcer agents are lacking (misoprostol) or inconsistent (ranitidine) at present. The role of Helicobacter pylori is controversial in NSAID users, but there is now wide agreement that H. pylori infection increases mucosal damage and the risk of upper GI bleeding in low-dose aspirin users.     

Prophylactic effect of rebamipide on aspirin-induced gastric lesions and disruption of tight junctional protein zonula occludens-1 distribution

Aspirin and nonsteroidal anti-inflammatory agents are known to induce gastroduodenal complications such as ulcer, bleeding, and dyspepsia. In this study, we examined the prophylactic effect of rebamipide, an anti-ulcer agent with free-radical scavenging and anti-inflammatory effect, on acidified aspirin-induced gastric mucosal injury in rats. In addition, we investigated the mucosal barrier functions disrupted by aspirin. Oral administration of acidified aspirin resulted in linear hemorrhagic erosions with increasing myeloperoxidase activity and thiobarbituric acid-reactive substance concentrations in the gastric mucosa. Rebamipide suppressed these acidified aspirin-induced gastric lesions and inflammatory changes significantly, and its protective effect was more potent in the case of repeated (twice daily for 3 days) treatment than single treatment before aspirin administration. Immunostaining of zonula occludens (ZO)-1, one of the tight junctional proteins, was strengthened in rat gastric mucosa after repeated administration of rebamipide. In addition, aspirin induced the increasing transport of fluorescine isothiocyanate-labeled dextrans with localized disruption and decreased expression of ZO-1 protein on rat gastric mucosal cell line RGM-1. Rebamipide effectively prevented aspirin-induced permeability changes and disruption of ZO-1 distribution. These results suggest that rebamipide protects against aspirin-induced gastric mucosal lesions by preserving gastric epithelial cell-to cell integrity in addition to the anti-inflammatory effects.     

Relationship between lesion formation and permeability of rat gastric mucosa to H+ and other cations.

The relationship between lesion formation and ionic permeability has been investigated in rat gastric mucosa in vivo. Changes in these parameters were measured in the mucosa treated topically with prostaglandins E2 and A2 and/or aspirin. Particular attention was paid to the net flux of H+ ions across the gastric mucosa. The effect of aspirin concentrations of 5 mM, 20 mM and '40 mM' (the latter, a suspension in a saturated solution) was investigated. Aspirin concentrations of 20 mM and '40 mM' produced a marked increase in lesion formation and increased the net mucosal to serosal flux of H+ ions. Aspirin 5 mM produced a significant increase in lesion formation but did not cause a significant change in net H+ ion flux. This result suggests that aspirin can have a direct irritant effect on the gastric mucosa and that the back diffusion of H+ ions is not a pre-requisite for the development of overt mucosal ulceration. The effect of topically applied prostaglandin E2 (PGE2) on aspirin-induced gastric mucosal damage was investigated. Concentrations of PGE2 of 10(-5) M and 10(-4) M ameliorated aspirin-induced damage, but these changes were not necessarily accompanied by a significant reduction in net H+ ion flux. Again, this result is not consistent with a direct relationship between lesion formation and mucosal permeability to H+ ions. Since PGA2 did not ameliorate aspirin-induced mucosal damage, the protective effect of PGE2 could not be attributed to its conversion to PGA2 in the acidic environment of the gastric lumen.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ranitidine: differential effects on gastric bleeding and mucosal damage induced by aspirin

This study investigated the influence of ranitidine on mucosal injury and gastric bleeding in 20 normal volunteers taking 600 mg aspirin q.d.s. This study was a double-blind placebo controlled crossover study comparing ranitidine, as 150 mg b.d., 300 mg q.d.s. and 600 mg b.d. with placebo. Gastric mucosal injury was assessed at unsedated endoscopy by counting haemorrhagic and non-haemorrhagic erosions; bleeding was measured in gastric washings. Aspirin alone increased mucosal injury from 0 to 11.4 erosions (mean, P < 0.01) and bleeding from 1.77 to 9.11 microliters blood/10 min (mean P < 0.001). Ranitidine prophylaxis reduced bleeding to 5.34, 3.18 and 3.47 microliters/10 min with 150 mg b.d., 300 mg q.d.s. and 600 mg b.d. respectively (overall effect of ranitidine P < 0.001) and also reduced haemorrhagic erosions though it had no effect on the total number of erosions. Ranitidine is effective at reducing aspirin-induced gastric bleeding and whilst not reducing aspirin-induced gastric erosions, it does reduce the number that appear haemorrhagic. Ranitidine may have a role in the prophylaxis of aspirin-induced gastric bleeding.     

Nonsteroidal antiinflammatory drug-induced mucosal lesions of the upper gastrointestinal tract and their relationship to Helicobacter pylori

The aim of the present study was to determine the prevalence of Helicobacter pylori infection in a group of patients hospitalized at the clinic of rheumatology who presented peptic ulcers and erosions associated with nonsteroidal antiinflammatory drugs (NSAIDs). Of a group of 4,256 hospitalized patients receiving therapy with NSAIDs, 221 patients with persistent dyspepsia underwent endoscopic examination of the upper segment of the gastrointestinal tract. Among them, mucosal abnormalities in the stomach and duodenum were confirmed in 69 patients. H. pylori was found in 42% (29/69) of the examined patients. Peptic ulcers were confirmed in 19 patients. Localization was gastric in 12 patients and duodenal in seven. H. pylori was found in only 17% of the patients (2/12) with gastric ulcers, but in as many as 86% (6/7) of those with duodenal ulcers. Patients with H. pylori taking NSAIDs were at higher risk of developing duodenal mucosal abnormalities, both ulcers (OR: 10.17; 95% CI: 1.08-23.88, p = 0.013) and erosions (OR: 2.67; 95 CI: 1.94-3.66, p = 0.001). Concomitant administration of corticoids and NSAIDs did not increase the risk of gastrotoxicity in patients with positive finding of H. pylori (OR: 0.32; 95% CI: 0.1-0.96). In conclusion, a close association was found between H. pylori infection and duodenal ulcers and erosions, but not between gastric ulcers and gastric erosions in a group of patients hospitalized for rheumatic diseases and undergoing NSAID therapy.     

Effects of fasting, stress and drugs on gastric glycoprotein synthesis in the rat.

1 The relationship between gastric mucosal damage and synthesis of gastric glycoproteins, as measured by the rate of incorporation of N-acetyl-[3H]glucosamine, was investigated in rats after fasting and restraint stress and a single administration of aspirin (200 mg/kg, orally), phenylbutazone (200 mg/kg, orally), prednisolone (200 mg/kg, orally), or adrenaline (2 mg/kg, i.p.). In one experiment, the effects of aspirin and phenylbutazone on carbohydrate content of the glycoproteins were also determined. 2 Restraint stress, phenylbutazone and aspirin resulted in acute gastric mucosal erosions in some of the rats. Adrenaline produced severe sub-mucosal haemorrhage, but no erosions or ulceration, while prednisolone and fasting gave no gross pathology. 3 The rate of incorporation of N-acetyl-[3H]glucosamine into glycoproteins was decreased after all treatments except adrenaline. In the groups receiving restraint stress, aspirin or phenylbutazone, the decreases were more marked in rats which developed erosions than in those with no gastric pathology. 4 Aspirin and phenylbutazone also produced changes in the carbohydrate content of the glycoproteins, the effects again being greater in the rats which developed erosions. 5 The results are discussed in the context of a possible association between erosion formation and glycoprotein synthesis and it is proposed that inhibition of mucus glycoprotein biosynthesis may be one mode of action of stress and drugs in causing gastric mucosal damage.     

Inhibition of Helicobacter pylori-induced cyclo-oxygenase-2 aggravates NSAID-caused gastric damage in Mongolian gerbils

BACKGROUND: The effect of Helicobacter pylori infection on non-steroidal anti-inflammatory drug-induced gastric mucosal injury is controversial. AIM: To examine the effect of the interaction between H. pylori and non-steroidal anti-inflammatory drugs on gastric mucosal injury. METHODS: Mongolian gerbils infected with H. pylori were treated with indometacin at 8 mg/kg for 2 days or 7 days. Mucosal damage was assessed by macroscopic and histological examination, and myeloperoxidase activity was measured as an index of neutrophil infiltration. The expression levels of cyclo-oxygenase proteins were determined by Western blot analysis and cyclo-oxygenase activity. RESULTS: A 2-day course of indometacin did not cause an increase in gastric damage in H. pylori-infected Mongolian gerbils compared to uninfected gerbils, while a 7-day course of indometacin caused additive gastric damage in H. pylori-infected animals. H. pylori infection induced cyclo-oxygenase-2 expression in the stomach. Treatment with indometacin for 2 days did not significantly affect cyclo-oxygenase activity in H. pylori-infected animals, while treatment for 7 days inhibited both cyclo-oxygenase-1 and cyclo-oxygenase-2 activities. Pre-treatment with a selective cyclo-oxygenase-2 inhibitor aggravated mucosal injury in H. pylori-infected animals treated or not treated with indometacin for 2 days. CONCLUSIONS: Our results suggest that cyclo-oxygenase-2 protein induced by H. pylori infection may be involved in the defence of the gastric mucosa against damage caused by non-steroidal anti-inflammatory drugs. Therefore, inhibition of cyclo-oxygenase-2 activity may enhance non-steroidal anti-inflammatory drug-caused gastric damage in H. pylori-infected animals.     

Specific inhibition of cyclooxygenase-2 with MK-0966 is associated with less gastroduodenal damage than either aspirin or ibuprofen

BACKGROUND: Compared with currently available NSAIDs (which inhibit COX-1 and COX-2 isoforms of cyclooxygenase), MK-0966 (a specific COX-2 inhibitor) is expected to cause less gastrointestinal toxicity. AIM: To compare the effect on the upper gastrointestinal mucosae of a high dose of MK-0966 with that of conventional doses of ibuprofen and aspirin. METHODS: Healthy subjects (n = 170; age range 18-54 years) with endoscopically normal gastric and duodenal mucosa were randomized to either MK-0966 250 mg q.d. (n = 51), ibuprofen 800 mg t.d.s. (n = 51), aspirin 650 mg q.d.s. (n = 17), or placebo (n = 51) in this 7-day, double-blind, parallel-group study. The mucosae were evaluated by endoscopy using a predefined scale; scores could range from 0 to 4. The primary end-point was the percentage of subjects who developed a mucosal score >/= 2 (i.e. the development of one or more erosions). To evaluate COX-1 activity, serum thromboxane B2 levels were determined in a subset of the population. RESULTS: The percentage of subjects who developed a mucosal score >/= 2 in the MK-0966 group (12%) was significantly lower (P < 0.001) than that in the ibuprofen (71%) and aspirin (94%) groups, and was similar to that in the placebo group (8%). Only ibuprofen and aspirin significantly (P < 0.0001) reduced baseline thromboxane B2 levels. All treatments were generally well tolerated. CONCLUSIONS: In this acute short-term endoscopic study, MK-0966 250 mg q.d. (a dose at least 10 times higher than that demonstrated to reduce the signs and symptoms of osteoarthritis) produced significantly less gastrointestinal mucosal damage than either ibuprofen 800 mg t.d.s. or aspirin 650 mg q.d.s. and was comparable to placebo in this regard.     

NSAID-induced peptic ulcers and Helicobacter pylori infection: implications for patient management.

The conflicting data about the influence of Helicobacter pylori infection on the ulcer risk in patients receiving NSAIDs can be accounted for by the heterogeneity of study designs and the diversified host response to H. pylori. Factors that will affect the outcome include the choice of H. pylori diagnostic tests, previous ulcer complications, concurrent use of acid suppressants, NSAID-naive versus long-term users, low-dose aspirin (acetylsalicylic acid) versus non-aspirin NSAIDs and whether the result was derived from a pre-specified endpoint or post hoc subgroup analysis. Current evidence suggests that H. pylori eradication reduces the ulcer risk for patients who are about to start receiving NSAIDs but not for those who are already on long-term NSAID therapy. Since treatment with a proton pump inhibitor (PPI) worsens H. pylori-associated corpus gastritis, H. pylori should be tested for, and eradicated if present, before starting long-term prophylaxis with PPIs. Patients with H. pylori infection and a history of ulcer complications who require NSAIDs should receive concomitant PPIs or misoprostol after curing the infection. Among patients receiving low-dose aspirin, who have H. pylori infection and previous ulcer complications, long-term treatment with a PPI further reduces the risk of complicated ulcers if H. pylori eradication fails or if patients use concomitant non-aspirin NSAIDs. Current data on the gastric safety of COX-2 selective NSAIDs in H. pylori-infected patients are conflicting. Limited data suggest that the gastroduodenal sparing effect of rofecoxib is negated by H. pylori infection in patients who have had prior upper gastrointestinal events. In light of potential cardiovascular risk with COX-2 selective NSAIDs, it is important to weigh the potential adverse effects against the benefits for an individual patient.     

Cimetidine decreases aspirin-induced gastric mucosal damage in humans

Aspirin induces gastric mucosal damage in animals and humans. The purpose of this study was to examine whether cimetidine protects the human gastric mucosa from acute aspirin-induced damage. Eight healthy subjects were studied on 4 separate days. Cimetidine, 400 mg, or placebo was given orally 1 hour before initial endoscopy. The stomach was isolated and atropine given to suppress basal acid secretion. Each study consisted of four 15 min periods during which an acidic test solution was instilled into the stomach. During the second period only, either aspirin (1300 mg, 36 mmol) or control for aspirin (36 mmol HCl) was added to the test solution. Ion fluxes and gastric mucosal potential difference were measured, and endoscopy performed following each test. After placebo, aspirin significantly altered hydrogen ion flux and potential difference versus basal and control. Cimetidine decreased the damaging effect of aspirin. Endoscopic scores increased after aspirin plus placebo, whereas they remained unchanged after aspirin plus cimetidine. Therefore, cimetidine decreased aspirin-induced gastric mucosal damage in humans. As gastric acidity was identical during all studies, the effect of cimetidine was independent of gastric acid secretion.     

Involvement of cyclooxygenase-2 in hyperplastic gastritis induced by Helicobacter pylori infection in C57BL/6 mice

BACKGROUND AND AIMS: The hyperplastic changes observed in Helicobacter pylori-associated gastritis have been considered to increase the risk of gastric cancer. The aim of this study was to determine whether cyclooxygenase-2 is involved in the hyperplastic changes in mice infected with H. pylori. METHODS: Seven-week-old, male C57BL/6 mice (n=40) were inoculated with the Sydney strain of H. pylori. Control mice (n=40) were treated with vehicle only. Half of the infected and control mice were fed an experimental diet containing etodolac (10 mg/kg/day) from 1 week after inoculation until the end of the experiment. The thickness of gastric pits, COX-2 mRNA and protein levels, and prostaglandin E2 (PGE2) levels in the gastric mucosa were determined before and 12, and 24 weeks after inoculation. RESULTS: The thickness of gastric pits, COX-2 mRNA and protein levels, and PGE2 levels were significantly increased at 24 weeks after inoculation of H. pylori compared with the control groups. Treatment with etodolac resulted in significant decreases in PGE2 production and in the thickness of gastric pits in the infected groups at 24 weeks after inoculation. CONCLUSIONS: Our findings suggest that COX-2 is involved in the development of hyperplastic gastritis caused by H. pylori infection via the production of PGE2.     

Recent advances in gastric ulcer therapeutics

In developed countries at least, ulcers related to Helicobacter pylori infection are becoming rarer. However, ulcers associated with the use of non-steroidal anti-inflammatory drugs (NSAIDs) remain a major clinical problem, which has not been solved through the introduction of selective inhibitors of cyclooxygenase (COX)-2. Recent studies suggest that NSAID-induced ulcers can be prevented largely through co-administration of a proton pump inhibitor to block acid secretion in the stomach. In patients requiring aspirin therapy to prevent cardiovascular diseases, co-administration of aspirin plus a proton pump inhibitor was found to be safer than using another anti-platelet therapy that does not block gastric prostaglandin production (e.g. clopidogrel). Several recent papers have clarified further the contribution of COX-2 to gastric mucosal defence and to the healing of ulcers. In some circumstances, COX-2 produces a highly potent gastroprotective substance (15-R-lipoxin A(4)), and analogues of this substance could have therapeutic value for preventing gastric ulceration. Nitric oxide-releasing NSAIDs continue to show promise in terms of limiting damage to the gastrointestinal tract, even when given in combination with aspirin. Recent studies support the notion that platelets make a major contribution to ulcer healing, and the release of several key growth factors from platelets appears to be regulated by proteinase-activated receptors.     

Review article: the effect of Helicobacter pylori infection on nonsteroidal anti-inflammatory drug-induced upper gastrointestinal tract injury

Helicobacter pylori and nonsteroidal anti-inflammatory drugs (NSAIDs) are the two major causes of peptic ulcers. This article reviews the interaction of H. pylori and NSAIDs on the development of gastric mucosal histological changes, endoscopically confirmed ulcers, and ulcer complications, and assesses whether underlying H. pylori infection potentiates (or mitigates) the development of NSAID-induced ulcer disease. The weight of evidence does not suggest that H. pylori infection potentiates the risk of ulcer formation or ulcer complications in NSAID users. If such an effect occurs, it is likely to be relatively small. Some data even suggest that H. pylori may be protective against NSAID-induced gastric ulcers. Limited data raise the possibility that H. pylori infection, however, may potentiate the effect of low-dose aspirin with respect to ulcer bleeding. Both NSAIDs and H. pylori are independent risk factors for ulcer disease. Therefore, in an individual patient with an ulcer, one cannot be certain which factor is responsible for the ulcer, and both risks should be removed if possible.