Effects of low-dose aspirin on gastric erosions, cyclooxygenase expression and mucosal prostaglandin-E2 do not depend on Helicobacter pylori infection

Inflammatory microRNAs in gastric mucosa are modulated by Helicobacter pylori infection and proton-pump inhibitors but not by aspirin or NSAIDs

Gastric carcinogenesis is associated with alterations of microRNAs (miRNAs) and reversal of these alterations may be a crucial element in cancer prevention. Here we evaluate the influence of H. pylori eradication, low-dose aspirin (LDA), non-steroidal anti-inflammatory drugs (NSAIDs) and proton-pump inhibitors (PPI) on modification of inflammatory mucosal miRNAs miR-155 and miR-223 in Helicobacter pylori-infected and non-infected subjects. The study was performed in two parts: 1) interventional study in 20 healthy subjects with and without H. pylori infection or following eradication (each n = 10) where LDA (100 mg) was given daily for 7 days; 2) prospective case-control observational study (n = 188). MiR-155 and miR-223 expression was strongly linked to H. pylori-infection and in short-term view showed a trend for reversal after eradication. Daily LDA as well as regular NSAIDs showed no influence on miRNAs expression both in healthy subjects and patients, while regular PPI intake was associated with lower miR-155 expression in antrum of patients with chronic gastritis independent of density of neutrophils and mononuclear infiltrate. In summary, PPI but not LDA or NSAIDs were associated with modification of inflammatory miRNAs miR-155 and miR-223 in an H. pylori dependent manner. The functional role of inflammatory miR-155 and miR-223 in understanding of H. pylori-related diseases needs further evaluation.

Teprenone for the prevention of low-dose aspirin-induced gastric mucosal injury in Helicobacter pylori-negative patients

Objectives: Low-dose aspirin is the standard treatment for the prevention of cardiovascular events in at-risk patients. We performed a randomized, placebo-controlled study to determine the efficacy of teprenone for primary prevention of gastrointestinal injury in patients taking LDA for vascular protection.Methods: Patients were eligible for enrollment if they required aspirin 100 mg/day. Aspirin- naïve patients without gastroduodenal ulcer and Helicobacter pylori infection were randomized to receive teprenone 150 mg/day or placebo for 12 weeks. Primary outcome was assessed by the incidence rate of gastroduodenal ulcer. Secondary outcomes were assessed by the incidence rate of gastric mucosal injury, the improvement in modified Lanza score (MLS), gastrointestinal symptom rating scale (GSRS) and the change of gastric immunohistochemical expression for COX-1.Results: Total of 130 patients were randomized, 64 in teprenone group and 66 in placebo group. There was no incidence of ulcer after 12 weeks in both groups. Incidence of gastric mucosal injury was higher in placebo group than in teprenone group (40.0 vs. 13.38%, p = .039). Mean change of MLS was higher in placebo group than in teprenone group (0.767 ± 0.467 vs. 0.271 ± 0.158, p = .003). Scores of mucosal edema, hyperemia and hemorrhage and the change of GSRS were not different between the two groups. Change of COX-1 immunoreactive score was higher in placebo group than in teprenone group (2.433 ± 1.476 vs. 1.233 ± 0.955, p = .001). There were no treatment-related adverse events.Conclusions: Teprenone is effective in preventing gastric mucosal injury in patients taking LDA. Preventive effects of teprenone on LDA-related gastroduodenal ulcers require further investigation.

Clinical and tumor significance of tropomyosin-1 expression levels in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common type of kidney cancer in adults and has been described as one of the deadliest of cancers affecting the genitourinary tract. Tropomyosin is a two-stranded α-helical coiled coil protein found in cell cytoskeletons. One of its isoforms, tropomyosin-1 (TPM1) has been reported as a novel tumor-suppressor gene and is downregulated in many solid tumors. However the expression level and function of TPM1 in RCC have not yet been determined. In the present study, we evaluated the TPM1-4 mRNA and TPM1 protein levels in RCC tissue samples. TPM1-overexpressing OSRC-2 and 786-O cell lines were also used to investigate the impact of TPM1 on RCC cells. We found that TPM1 was significantly and specifically downregulated in the RCC tissues. TPM1 expression was associated with tumor size, smoking status, Fuhrman grade and the prognosis of RCC patients. After TPM1 transfection, the migratory and invasive abilities of the OSRC-2 and 786-O cell lines were both reduced when compared to the control groups. Meanwhile, apoptosis was also enhanced in these two RCC cell lines following TPM1 transfection. Taken together, TPM1 exhibits characteristics of a tumor-suppressor gene while being overexpressed in RCC cell lines.

Increased gastric mucus secretion alleviates non-steroidal anti-inflammatory drug-induced abdominal pain

Non-steroidal anti-inflammatory drugs (NSAIDs) can cause dyspeptic symptoms, including abdominal pain. Gastric mucus is important as the first line of defense against luminal irritants. In the present study, we investigated whether gastric mucus secretion could influence the severity of gastric mucosal injuries or NSAID-induced dyspeptic symptoms. Fifteen Helicobacter pylori-negative, healthy males were administered two types of NSAIDs, a non-selective cyclooxygenase inhibitor, naproxen (300 mg, twice a day), or a cyclooxygenase-2-selective inhibitor, etodolac (200 mg, twice a day), for 1 week in a crossover study, with an interval of ≥ 4 weeks. Study participants underwent endoscopic examinations before and after treatment. Pentagastrin-stimulated gastric secretions were collected for 10 min during endoscopic examinations, and were analyzed for gastric acid levels (mEq/10 min) and mucus output (mg hexose/10 min). The grade of gastric mucosal injury was assessed endoscopically. Among 29 subjects who completed the crossover study, 11 individuals reported abdominal pain following the administration of naproxen or etodolac for 1 week, as judged by elevated pain scores, while 18 individuals did not report abdominal pain. The occurrence of symptoms was not associated with the type of NSAIDs administered or the occurrence of erosive injury visualized by endoscopy. Gastric mucus secretion was significantly increased in subjects without drug-induced abdominal pain (P < 0.05), whereas it was significantly reduced in those with drug-induced abdominal pain (P < 0.05). In conclusion, the occurrence of NSAID-induced abdominal pain is associated with reduced levels of gastric mucus secretion rather than the occurrence of endoscopic mucosal injury.

Reactive increase in gastric mucus secretion is an adaptive defense mechanism against low-dose aspirin-induced gastropathy

BACKGROUND

Gastric mucus is considered to play an essential role in gastric mucosal defense mechanisms, especially when irritants are present in the stomach.

AIM

To investigate the relationship between low-dose aspirin-induced gastropathy and gastric secretory function, especially gastric mucus secretion, in healthy volunteers.

METHODS

Thirty male, asymptomatic, Helicobacter pylori pylori-negative healthy volunteers were asked to take 100 mg of enteric-coated aspirin (Bayaspirin) once a day for 10 days. Endoscopic examination was performed before and 3 and 10 days after drug administration. The extent of endoscopically assessed gastric mucosal injury was semi-quantitatively evaluated according to the modified Lanza score. The pentagastrin-stimulated gastric juice was collected for 10 min during the endoscopic examination and subjected to analysis for gastric acid (mEq/10 min) or mucus (mg hexose/10 min) output.

RESULTS

Overall, the 10-day aspirin treatment significantly increased gastric mucus secretion from 0.8 (interquartile range 1.7) to 1.6 (1.6) mg hexose/10 min (P < 0.05), with a concomitant and significant decrease in the gastric acid/mucus ratio from 4.3 (5.2) to 2.9 (4.7) (P < 0.01). Subsequent analysis of two subgroups of volunteers categorized according to their endoscopic status ("severe gastropathy" vs. "modest gastropathy") revealed that changes in gastric secretory parameters occurred exclusively in those subjects without severe gastric injury; there was no alteration in these parameters in subjects with severe gastric injury.

CONCLUSIONS

The results of this study suggest that the reactive increase in gastric mucus secretion is an adaptive defense mechanism against low-dose aspirin-induced gastropathy. In some individuals, such a response may be insufficient to prevent the development of severe mucosal injury and even ulcers and their complications.

Differential expression of human beta defensin 2 and 3 in gastric mucosa of Helicobacter pylori-infected individuals

BACKGROUND

Antimicrobial peptides are key players of initial innate immune responses to human pathogens. Two major representatives, the human beta defensin 2 and 3 (hBD2 and hBD3), are both known to be regulated by, and to affect viability of, Helicobacter pylori. Previously, it was demonstrated in vitro that H. pylori actively abrogates hBD3 expression during prolonged infections. Here, we comprehensively assessed hBD2 and hBD3 expression ex vivo in the gastric mucosa of healthy individuals.

MATERIALS AND METHODS

Twenty volunteers (H. pylori positive and H. pylori negative: n = 10) were enrolled. Helicobacter pylori-positive subjects underwent eradication therapy and repeated the protocol. Expression of both defensins was assessed by quantitative RT-PCR and ELISA, and correlated with histopathologic degree of gastritis.

RESULTS

hBD2 and hBD3 were found to be ubiquitously expressed in all three groups. In general, hBD2 levels were elevated in relation to H. pylori infection (up to 40-fold). This upregulation correlated with degree of gastritis in corpus and antrum. In contrast, hBD3 protein levels were significantly decreased, while corresponding mRNA amounts remained unchanged. Eradication therapy led to normalization of mucosal hBD2 expression, while hBD3 expression demonstrated high interindividual variations among individuals.

CONCLUSIONS

Both defensins are ubiquitously but differentially expressed in gastric mucosa in relation to H. pylori infection. Ex vivo data support the notion that H. pylori infection is associated with reduced hBD3 expression in chronic active gastritis.

Expression pattern of cathepsin W isoforms in peripheral blood and gastroesophageal mucosa of patients with gastroesophageal reflux disease

Cathepsin W is exclusively expressed in immune cells, and a novel isoform was identified previously. To characterize the expression pattern of the wildtype and isoform Ins10, specific polymerase chain reaction assays were generated and used to study respective transcript levels in peripheral blood cells and gastric biopsies in healthy subjects. The wildtype-encoding transcript levels were 3- and 9-fold higher in mucosal samples and peripheral immune cells, respectively (p<0.05). The predominant expression of wildtype form by infiltrating immune cells was confirmed in 116 patients with gastroesophageal reflux disease and 27 reflux-negative individuals demonstrating that cathepsin W expression is not altered in this disease.

Phase II study of the effects of ginger root extract on eicosanoids in colon mucosa in people at normal risk for colorectal cancer

Inhibitors of COX indicate that upregulation of inflammatory eicosanoids produced by COX, and in particular prostaglandin E(2) (PGE(2)), are early events in the development of colorectal cancer (CRC). Ginger has shown downregulation of COX in vitro and decreased incidence/multiplicity of adenomas in rats. This study was conducted to determine if 2.0 g/d of ginger could decrease the levels of PGE(2), 13-hydroxy-octadecadienoic acids, and 5-, 12-, and 15-hydroxyeicosatetraenoic acid (5-, 12-, and 15-HETE), in the colon mucosa of healthy volunteers. To investigate this aim, we randomized 30 subjects to 2.0 g/d ginger or placebo for 28 days. Flexible sigmoidoscopy at baseline and day 28 was used to obtain colon biopsies. A liquid chromatography mass spectrometry method was used to determine eicosanoid levels in the biopsies, and levels were expressed per protein or per free arachidonic acid. There were no significant differences in mean percent change between baseline and day 28 for any of the eicosanoids, when normalized to protein. There was a significant decrease in mean percent change in PGE(2) (P = 0.05) and 5-HETE (P = 0.04), and a trend toward significant decreases in 12-HETE (P = 0.09) and 15-HETE (P = 0.06) normalized to free arachidonic acid. There was no difference between the groups in terms of total adverse events P = 0.55). On the basis of these results, it seems that ginger has the potential to decrease eicosanoid levels, perhaps by inhibiting their synthesis from arachidonic acid. Ginger also seemed to be tolerable and safe. Further investigation in people at high risk for CRC seems warranted.

Interaction of Helicobacter pylori infection and nonsteroidal anti-inflammatory drugs in gastric and duodenal ulcers

BACKGROUND

Gastric (GU) and duodenal ulcers (DU) are in most instances either induced by Helicobacter pylori infection or by nonsteroidal anti-inflammatory drugs (NSAIDs). Whether eradication of H. pylori is beneficial in NSAID users for preventing NSAID induced GU and DU has been the focus of different studies.

MATERIALS AND METHODS

Mechanisms shared by both H. pylori and NSAIDs for the induction of GU and DU were reviewed and randomized controlled trials on H. pylori eradication for prevention and healing of GU and DU in patients requiring NSAID therapy were identified by a PubMed search.

RESULTS

Key factors in the induction of GU and DU for both H. pylori and NSAIDs are a decrease in pH, imbalance between apoptosis and proliferation, reduction in mucosal blood flow, and recruitment of polymorphonucleates in distinct compartments. For primary ulcer prevention, H. pylori eradication before starting an NSAID therapy reduces the risk of NSAID induced GU and virtually abolishes the risk of DU. H. pylori eradication alone is not sufficient for secondary prevention of NSAID induced GU and DU. H. pylori infection appears to further increase the protective effects of proton-pump inhibitors (PPI) to reduce the risk of ulcer relapse. H. pylori eradication does not influence the healing of both GU and DU if NSAID intake is discontinued.

CONCLUSIONS

Duodenal ulcer is more closely related to H. pylori infection than GU in NSAID users. H. pylori eradication is recommended for primary prevention of GU and DU in patients requiring NSAID therapy. PPI therapy is mandatory for secondary prevention of gastroduodenal ulcers, and appears to further reduce the risk of ulcer relapse in the presence of H. pylori.

Gastroduodenal toxicity of low-dose acetylsalicylic acid: a comparison with non-steroidal anti-inflammatory drugs

BACKGROUND

Low-dose acetylsalicylic acid (ASA; aspirin; 75-325 mg/day) is effective for the prevention of cardiovascular events, and its use in this indication is rapidly increasing. However, the use of ASA and, indeed, other non-steroidal anti-inflammatory drugs (NSAIDs) is limited by the incidence of adverse gastroduodenal events. OBJECTIVES AND SCOPE: To review the clinical evidence for, and the pharmacodynamic basis of, ASA-induced gastroduodenal toxicity in comparison with NSAIDs, and address the question of whether low-dose ASA is 'safe' from a gastroduodenal perspective. This was a narrative, descriptive review, rather than a formal systematic review.

FINDINGS

Adverse gastroduodenal effects, which are well known to occur with NSAIDs, are also prevalent in patients receiving low-dose ASA for cardiovascular protection even at doses as low as 75 mg/day. The risk of gastroduodenal toxicity is particularly high among 'at-risk' low-dose ASA patients (aged >70 years, previous ulcer or upper gastrointestinal bleeding and users of antiplatelets or NSAIDs). There are important differences in the mechanism of ASA-induced gastroduodenal toxicity, relative to NSAIDs. These differences include the effects on the cyclooxygenase (COX)-1 isoenzyme, local effects on the gastroduodenal mucosa specific to ASA and a reduction in platelet aggregation.

CONCLUSION

Data suggest that ASA causes significant gastroduodenal damage even at the low doses used for cardiovascular protection. These effects (both systemic and possibly local) may be pharmacodynamically distinct from the gastroduodenal toxicity seen with NSAIDs. Studies are required to establish strategies for improving the tolerability of low-dose ASA, allowing patients to continue to benefit from the cardiovascular protection associated with such therapy.

Influence of cyclooxygenase inhibitors on the function of the prostaglandin transporter organic anion-transporting polypeptide 2A1 expressed in human gastroduodenal mucosa

The human organic anion-transporting polypeptide 2A1 (OATP2A1) is a prostaglandin transporter expressed in several tissues and plays an important role for local distribution of prostaglandins, which contribute to the integrity of gastric mucosa. Blockade of prostaglandin pathways by cyclooxygenase (COX) inhibitors has been associated with serious side effects such as gastrointestinal ulceration and bleeding. However, little is known regarding OATP2A1 expression in the upper gastrointestinal tract and the potential impact of cyclooxygenase inhibitors on OATP2A1 function. We first investigated the expression of OATP2A1 mRNA and protein in human gastroduodenal mucosa using human biopsy specimens obtained from antrum, corpus, and duodenum. The results indicate that OATP2A1 is expressed in the neck region and deep pyloric glands of antrum and in parietal cells of gastric corpus. Second, we examined various COX inhibitors for their effects on OATP2A1 transporter activity. Using HEK293 cells expressing OATP2A1, we found that diclofenac and lumiracoxib are potent inhibitors of OATP2A1-mediated transport of prostaglandin (PG) E(2) with IC(50) values of 6.2 +/- 1.2 and 3.1 +/- 1.2 microM. In contrast, indomethacin, ketoprofen, and naproxen led to significant stimulation of OATP2A1-mediated PGE(2) transport by 162.7 +/- 13.9, 77.2 +/- 3.6, and 32.3 +/- 4.9%, respectively. Taken together, our results suggest that various clinically used COX inhibitors have differential impact on the function of the prostaglandin transporter OATP2A1 in human stomach and that these effects may contribute to differences in the gastrointestinal side effects of COX inhibitors.

NSAID-induced antral ulcers are associated with distinct changes in mucosal gene expression

BACKGROUND

The basis for individual variation in gastroduodenal vulnerability to NSAIDs is not well understood.

AIM

To assess whether a gene expression signature is associated with susceptibility to gastroduodenal ulcerations.

METHODS

Twenty-five Helicobacter pylori negative adults were treated for 7 days with naproxen 500 mg b.d. Subjects underwent baseline and post-treatment endoscopy, during which biopsies were taken from antrum and duodenum. RNA extraction and cDNA synthesis were performed, followed by PCR of 23 genes relevant to mucosal injury and repair. Fold changes in gene expression were compared between subjects who developed ulcers and those who did not.

RESULTS

Compared with subjects who did not develop ulcers (n = 18), subjects who developed antral ulcers (n = 7) had significantly greater mucosal up-regulation of interleukin-8 [Fold change = 33.5 (S.E.M. = 18.5) vs. -7.7 (3.2)] and of cyclo-oxygenase-2 [2.3 (1.7) vs. -10.8 (2.2)]. Conversely, non-ulcer subjects had significantly greater up-regulation of toll-like receptor-4, cyclo-oxygenase-1 and hepatocyte growth factor [14.0 (2.2) vs. -0.8 (1.0), 9.8 (2.4) vs. 0.0 (0.7) and 8.2 (2.6) vs. -2.2 (0.3) respectively].

CONCLUSIONS

NSAID-induced antral ulcers are associated with a specific pattern of gastroduodenal mucosal gene expression. These patterns may provide an insight into the molecular basis of individual susceptibility to mucosal injury.

Helicobacter pylori infection and short-term intake of low-dose aspirin have different effects on alpha-1 antitrypsin/alpha-1 peptidase inhibitor (alpha1-PI) levels in antral mucosa and peripheral blood

OBJECTIVE

Alpha-1 protease inhibitor (alpha1-PI) is the major circulating serine protease inhibitor. The purpose of the study was to investigate alpha1-PI expression in gastroduodenal mucosa and blood with respect to two major etiological risk factors for gastroduodenal diseases, Helicobacter pylori infection and intake of low-dose aspirin.

MATERIAL AND METHODS

Twenty volunteers (H. pylori-positive and -negative: n=10) received 2 x 50 mg aspirin/day for 7 days. H. pylori-positive subjects underwent eradication therapy and repeated the protocol. Blood and tissue samples were obtained on days 0, 1, 3 and 7; alpha1-PI levels were determined by enzyme-linked immunosorbent assay (ELISA) and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and analyzed for histopathological findings.

RESULTS

Mucosal alpha1-PI expression was between 30 and 75 pg/10 microg total protein in H. pylori-negative subjects, and found to be similar in antral, corpus and duodenal mucosa. In H. pylori-infected subjects, alpha1-PI levels were significantly increased in the antrum (mean: 111 versus 37.4 pg/10 microg protein; p=0.019), whereas corresponding levels in the corpus, duodenum and sera were unchanged. Alpha-1-PI transcript levels were similarly induced in H. pylori-infected subjects (0.13+/-0.15 versus 0.027+/-0.043 a.u. (arbitrary units), p=0.018). Immunohistochemistry demonstrated that infiltrating immune cells and antral surface epithelium contributed to elevated alpha1-PI expression in H. pylori-infected subjects. The concomitant use of low-dose aspirin did not change mucosal alpha1-PI levels, but led to a 2-fold increase in alpha1-PI levels in sera independently of the H. pylori status (p<0.009).

CONCLUSIONS

Antral alpha1-PI expression is specifically induced by H. pylori infection, suggesting a pathophysiological role of this protease inhibitor in the upper gastrointestinal tract, whereas low-dose aspirin led to an increase in systemic alpha1-PI levels.

Low-dose aspirin reduces the gene expression of gastrokine-1 in the antral mucosa of healthy subjects

BACKGROUND

Gastrokine 1 (GKN1), one of the most abundant transcripts in normal stomach, is down-regulated by Helicobacter pylori infection. Aspirin (ASA), which is often used for secondary prevention of cardiovascular events, can damage gastric-duodenal mucosa within 1 or 2 h of ingestion.

AIM

To study the gastric mucosal expression of GKN1 during acute low-dose ASA consumption.

METHODS

Ten H. pylori-negative human volunteers took 100 mg ASA per day for 1 week, and underwent multiple upper GI endoscopies. GKN1 expression was analysed in antral and corpus mucosa by quantitative reverse-transcriptase polymerase chain reaction, western blot and immunohistochemistry (IHC). Gastric mucosal damage was detected endoscopically and histologically.

RESULTS

Gastrokine 1 was similarly expressed in both antral and corpus mucosa. The use of low-dose ASA led to a significant decrease (3.07 a.u. vs. 0.23 a.u., P < 0.001) in antrum at day 7, while GKN1 transcript levels in corpus mucosa were slightly elevated (twofold, P < 0.005). Western blot and IHC confirmed these changes at the protein level. Furthermore, IHC revealed a vesicular staining pattern in the cytoplasm for GKN1 that was confirmed by transfected human gastric adenocarcinoma cell line expressing GKN1.

CONCLUSION

Our data demonstrated that low-dose ASA downregulates GKN1 expression specifically in antral mucosa.

Short-term/low-dose aspirin-induced duodenal erosions are not dependent on Helicobacter pylori infection, cyclooxygenase expression and prostaglandin E2 levels

OBJECTIVE

The mechanisms of interaction between Helicobacter pylori infection and low-dose aspirin in the induction of duodenal erosions are not fully understood. The aim of this study was to investigate the effects of low-dose aspirin on the induction of duodenal erosions, the expression of cyclooxygenases and prostaglandin (PG)-E(2) levels in healthy subjects according to their H. pylori status.

MATERIAL AND METHODS

Twenty healthy volunteers (H. pylori-negative n=10, H. pylori-positive n=10) received 100 mg aspirin/day for 1 week. During esophagogastroduodenoscopy, duodenal biopsies were taken before and at days 1, 3, and 7 of medication. COX-1 and -2 expressions were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR), and immunohistochemistry; mucosal PGE(2) levels were determined by ELISA. Three months after successful eradication of infection, nine H. pylori-positive subjects repeated the protocol.

RESULTS

Aspirin-induced duodenal erosions occurred independently of whether H. pylori infection was present or not. There was no difference in duodenal COX-1 and COX-2 expression among the groups and expression was not affected by aspirin. Basal duodenal PGE(2) levels were similar among the different groups (H. pylori-negative 4.3+/-4.2, H. pylori-positive 5.2+/-1.3, following H. pylori eradication 5.2+/-1.4 ng/microg protein) and were not affected by low-dose aspirin.

CONCLUSIONS

In healthy subjects, low-dose aspirin-induced duodenal erosions are not influenced by H. pylori status. Low-dose aspirin medication for one week does not affect either cyclooxygenase expression or duodenal PGE(2) levels and therefore is likely to induce duodenal damage mainly through topical toxicity.

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.

Helicobacter pylori and non-malignant diseases

In recent years, the focus of Helicobacter pylori clinical research has been mainly on gastric malignancy. However, the role of H. pylori in non-malignant diseases, such as peptic ulcer, gastroesophageal reflux disease (GERD) and non-ulcer dyspepsia, as well as non-steroidal anti-inflammatory drug consumption, is still of great interest. A 1- to 2-week course of H. pylori eradication therapy is an effective treatment for H. pylori-positive peptic ulcer disease and a positive CagA status is a predictor for successful eradication of H. pylori. Antral prostaglandin-E2-basal levels appear to be critical for the development of aspirin-induced gastric damage in subjects without H. pylori infection. In clinical practice, among patients treated with proton-pump inhibitors, H. pylori status has no effect on the speed or degree of GERD symptom relief. For the management of dyspepsia in primary care, antisecretory therapy confers a small insignificant benefit compared to strategies based on H. pylori testing while these latter strategies may be cost-effective. H. pylori eradication therapy has a small but statistically significant effect on H. pylori-positive non-ulcer dyspepsia. An economic model suggests that this modest benefit may still be cost-effective but more research is needed.