Cyclooxygenase (COX) 1 and 2 in normal, inflamed, and ulcerated human gastric mucosa

BACKGROUND AND AIMS: Constitutive cyclooxygenase (COX) 1 is believed to mediate prostaglandin dependent gastric protection. However, gastric mucosa contains cells capable of expressing inducible COX-2. We therefore investigated COX-1 and COX-2 expression, localisation, and activity in normal and abnormal human gastric mucosa. METHODS: COX-1 and COX-2 distribution was investigated by light and electron microscopic immunohistochemistry and by western blot analysis, and their contribution to prostaglandin (PG)E(2) synthesis using selective enzyme inhibitors. RESULTS: There was strong parietal cell COX-1 and COX-2 immunoreactivity in all sections and isolated cells, with macrophage and myofibroblast reactivity in some sections. Immunostaining was specifically abolished by antigen absorption. Western blot analysis confirmed COX-1 and 2 expression. COX-1 and COX-2 immunostaining was increased in Helicobacter pylori gastritis, particularly the mid glandular zone and lamina propria inflammatory cells. This was associated with increased ex vivo PGE(2) synthesis (62.4 (13.5) pg/mg v 36.3 (15.5) pg/mg in uninflamed mucosa; p=0. 017) which was significantly inhibited by COX-1 but not COX-2 inhibition. Increased COX-2 immunostaining in macrophages, endothelial cells, and myofibroblasts (with reduced epithelial expression) was seen at the rim of ulcers. CONCLUSION: COX-2, as well as COX-1, is expressed by normal human gastric mucosa and is increased at the rim of ulcers. Although both are increased with H pylori, COX-1 contributes more than COX-2 to gastric PGE(2) production.     

The role of cyclooxygenase in gastric mucosal protection

COX-1 and COX-2 are two cyclooxygenase enzymes responsible for prostanoid production. COX-2 is expressed in inflammatory cells and fibroblasts of the gastric mucosa, and through the production of various growth factors including hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF), plays a key role in the tissue repair process. Aspirin induces and acetylates COX-2 to produce 15-(R)-epi-lipoxinA4, an anti-inflammatory mediator thought to protect the gastric mucosa against aspirin-induced injury. Recently, three different PGE synthases have been identified, that convert COX-2 metabolites into PGE2. mPGE synthase (mPGES)-1 has been shown to be inducible, and to colocalize with COX-2 in fibroblasts and macrophages infiltrating the gastric ulcer bed. cPGES and mPGES-2 have been found expressed in normal gastric mucosa, with no change in expression levels seen in gastritis or gastric ulcer tissue. Finally, this review discusses the role of these enzymes in the pathophysiology of the gastric mucosa, as well as the biologcal significance of their inhibition.     

Roles of Helicobacter pylori infection and cyclooxygenase-2 expression in gastric carcinogenesis

AIM: Cyclooxygenase (COX)-2 is over expressed in gastrointestinal neoplasm. Helicobacter pylori (H pylori) infection is causally linked to gastric cancer. However, the expression of COX-2 in various stages of H pylori-associated gastric carcinogenesis pathway has not been elucidated. Therefore, the aim of this study was to clarify the role of H pylori induced COX-2 expression during carcinogenesis in the stomach. METHODS: Gastric biopsies from 138 subjects (30 cases of chronic superficial gastritis (CSG), 28 cases of gastric glandular atrophy (GA), 45 cases of gastric mucosal intestinal metaplasia (IM), 12 cases of moderate gastric epithelial dysplasia and 23 cases of gastric cancer) were enrolled. H pylori infection was assessed by a rapid urease test and histological examination (modified Giemsa staining). The expression of COX-1 and COX-2 in human gastric mucosa was detected by immunohistochemical staining. RESULTS: H pylori infection rate was 64.3% in GA and 69.5% in gastric cancer, which was significantly higher than that (36.7%) in CSG (P<0.05). The positive expression rates of COX-2 were 10.0%, 35.7%, 37.8%, 41.7% and 69.5% in CSG, GA, IM, dysplasia and gastric cancer, respectively. From CSG to GA, IM, dysplasia and finally to gastric cancer, expression of COX-2 showed an ascending tendency, whereas COX-1 expression did not change significantly in the gastric mucosa. The level of COX-2 expression in IM and dysplasia was significantly higher in H pylori-positive than in H pylori-negative subjects (P<0.01). CONCLUSION: COX-2 expression induced by H pylori infection is a relatively early event during carcinogenesis in the stomach.     

Monocyte chemoattractant protein 1 (MCP-1) released from Helicobacter pylori stimulated gastric epithelial cells induces cyclooxygenase 2 expression and activation in T cells

BACKGROUND: and aims: To clarify the interaction between gastric epithelial and mucosal T cells, we examined the role of cytokines released from epithelial cells in response to Helicobacter pylori water extract protein (HPWEP) in regulating T cell cyclooxygenase 2 (COX-2) expression and activation. METHODS: Media from MKN-28 cells incubated with HPWEP for 48 hours were added to Jurkat T cells and human peripheral T cells. C-C and CXC chemokine concentrations in MKN-28 cell media, and COX-2 expression, interferon gamma (IFN-gamma), and interleukin (IL)-4 secretions in T cells were determined by western blot analysis and ELISA methods. Distributions of COX-2 positive T cells and monocyte chemoattractant protein 1 (MCP-1) in tissue specimens with H pylori associated gastritis were determined as single or double labelling by immunohistochemistry. RESULTS: MCP-1, IL-7, IL-8, and RANTES were detected in media from MKN-28 cells incubated with HPWEP. Media as a whole, and MCP-1 alone, stimulated COX-2 expression and peripheral T cell proliferation. Anti-MCP-1 antibody inhibited media stimulated COX-2 mRNA expression in Jurkat T cells. Media stimulated IFN-gamma but not IL-4 secretion from peripheral T cells, while MCP-1 stimulated IL-4 but not IFN-gamma secretion. Both stimulated cytokine release, and peripheral T cell proliferation was partially inhibited by NS-398, a specific COX-2 inhibitor. In mucosa with gastritis, COX-2 was expressed in T cells and MCP-1 was localised mainly in epithelial and mononuclear cells. MCP-1 levels and the intensity of COX-2 expression in tissue samples were closely related. CONCLUSIONS: Cytokines such as MCP-1, released from gastric epithelial cells in response to HPWEP, seem to modulate T cell immune responses, at least in part via COX-2 expression.     

Influence of COX-2 and local cytokine expressions in gastric ulcer mucosa by H. pylori and NSAID

BACKGROUND/AIMS: H. pylori and NSAIDs are the two most important pathogenic factors in gastric ulcer. NSAIDs and H. pylori share common pathogenic characteristics, but have different effects in modulating COX-2 and local cytokines in gastric ulcer mucosa. This study was designed to explore the influence of COX-2 and local cytokine expressions in gastric ulcer mucosa induced by H. pylori infection and NSAID use. METHODOLOGY: Twenty-three patients were recruited. Sixteen subjects were infected with H. pylori. Fifteen patients used NSAIDs. Gastric biopsy specimens were obtained by endoscopy. COX-2 and local cytokine mRNA expressions were assessed by real-time RT-PCR. RESULTS: COX-2 and local cytokines were over-expressed in gastric ulcer and were positively intercorrelated. H. pylori did not alter COX-2 and local cytokine expressions in gastric ulcer, but induced IL-8 and COX-2 in antral mucosa. NSAIDs inhibited COX-2 expression in gastric ulcer, but had no effect on other local cytokines. COX-2 inhibition by NSAIDs in gastric ulcer was compatible with the findings that NSAIDs delayed gastric ulcer healing. CONCLUSIONS: H. pylori increased IL-8 and COX-2 in the antral mucosa, but did not influence COX-2 and local cytokines in gastric ulcer. NSAIDs inhibited COX-2 in gastric ulcer and delayed gastric ulcer healing.     

The interaction of H. pylori infection and NSAIDs in cyclooxygenase-2 mRNA expression in gastric antral, corpus mucosa, and gastric ulcer

BACKGROUND: Although Helicobacter pylori infection and use of nonsteroidal anti-inflammatory drugs (NSAIDs) are the two major causes of gastric ulcer, their interaction remains controversial. We constructed a prospective cohort study to evaluate how these two factors influence the expression of COX-2 mRNA in gastric antral, corpus mucosa, and gastric ulcer. METHODS: Tissues were obtained by endoscopic biopsy of gastric antral, corpus mucosa, and gastric ulcer. The presence of H. pylori was determined by culture or histology using Giemsa stain. NSAID use was assessed by structured questionnaire and medical record review. The expression of COX-2 mRNA was detected by the TaqMan quantitative RT-PCR system. RESULTS: H. pylori infection was associated with increased COX-2 expression only in antral mucosa (0.77 +/- 0.13 vs. 0.31 +/- 0.07, P < 0.01). NSAID use was significantly associated with decreased COX-2 expression in ulcer (4.49 +/- 1.50 vs. 9.82 +/- 2.48, P < 0.05) but not in antral or corpus mucosa. Regarding the interaction between H. pylori and NSAID, we found that H. pylori infection was associated with increased COX-2 expression in antral mucosa for both NSAID users and nonusers. In NSAID users, H. pylori infection was not associated with increased COX-2 expression in ulcer edge. CONCLUSION: H. pylori infection was associated with increased COX-2 expression in gastric antral mucosa for both NSAID users and nonusers, but not in gastric ulcer, where the effect of NSAID inhibition plays a major role. With these observations, we can interpret indirectly that H. pylori eradication does not interfere with gastric ulcer healing in NSAID users.     

Effect of H. pylori on COX-2 expression in gastric remnant after distal gastrectomy

BACKGROUND/AIMS: Helicobacter pylori infection is known to induce gastritis, oxidative stress, and cyclooxygenase (COX)-2 expression in the gastric mucosa. However, the effect of H. pylori infection on remnant gastritis has not been studied. We investigated whether the severity of remnant gastritis and COX-2 expression were affected by H. pylori infection after distal gastrectomy. METHODOLOGY: The study included 97 patients with gastric cancer who underwent curative distal gastrectomy with lymphadenectomy in our department between May 1999 and April 2001. All patients underwent endoscopic examination 2 weeks before and 12 weeks after surgery. The presence of H. pylori infection was determined by urease activity, hematoxylin-eosin staining, and immunochemical staining. Histologic remnant gastritis was graded based on the degree of neutrophil infiltration using the updated Sydney System. COX-2 expression was estimated immunohistochemically. RESULTS: Both the degree of neutrophil infiltration and the level of COX-2 expression were significantly higher in patients with than without H. pylori (p<0.05). There was a significant correlation between the degree of neutrophil infiltration and the degree of COX-2 expression (p<0.001). CONCLUSIONS: H. pylori eradication may become a treatment for preventing both remnant gastritis as well as remnant gastric carcinoma after distal gastrectomy.     

幽门螺杆菌感染诱导胃粘膜环氧化酶-2表达

目的 探讨幽门螺杆菌（Hp)感染对胃粘膜环氧化酶－2（COX－2）表达的影响。方法 27例无任何症状健康检查者，经胃镜采取胃窦部粘膜组织，用于Hp检测、病理组织学检查及免疫组织化学检查COX－2的表达。结果 18例Hp感染者胃粘膜上皮细胞和炎症细胞表达COX－2，而9例Hp阴性者胃粘膜均不表达COX－2。结论 Hp感染诱导胃粘膜COX－2表达。     

Cyclooxygenase-2 expression in gastric antral mucosa before and after eradication of Helicobacter pylori infection

OBJECTIVE: Helicobacter pylori (H. pylori) causes chronic gastritis. The inducible prostaglandin synthetase cyclooxygenase 2 (COX-2) plays an important role in inflammatory conditions. We hypothesized that H. pylori-associated chronic gastritis would express COX-2 protein. Our aim was to evaluate the effect of eradication of H. pylori infection on COX-2 expression in the antral mucosa of patients before and after antibiotic therapy. METHODS: Tissues were obtained from patients with non-ulcer dyspepia undergoing H. pylori eradication. Ten patients with proven H. pylori infection and subsequent successful eradication were studied. Three biopsies of antral mucosa were evaluated before and after H. pylori eradication. The amount of acute and chronic inflammation was quantitated. Immunohistochemical staining for COX-2 was expressed as a percentage of the total number of cells and correlated with the degree of chronic inflammation. RESULTS: Specific immunostaining for COX-2 was observed in antral mucosa of patients infected with H. pylori. Patchy cytoplasmic staining was seen in surface epithelial cells and strong cytoplasmic staining for COX-2 was seen in parietal cells. Spotty cytoplasmic staining for COX-2 was also seen in lamina propria plasma cells, as well as there being macrophages present in the germinal centers of lymphoid aggregates. COX-2 expression could be detected both before and after eradication of H. pylori. The mean percentage of cells staining for COX-2 was significantly higher in H. pylori-infected mucosa, compared with mucosa after successful H. pylori eradication (33.4% +/- 5.4 vs 18.9% +/- 3.3, p = 0.038). COX-2 immunostaining correlated best with the chronic inflammation score (r2 = 0.78, p < 0.001). There was a strong correlation for those subjects who were H. pylori infected, as well as for those who had successful H. pylori eradication. CONCLUSIONS: H. pylori associated acute and chronic antral inflammation was associated with immunohistochemical detection of COX-2 protein in epithelial cells, in addition to associated mononuclear cells and parietal cells. Expression was reduced, but not eliminated, in the epithelium after successful eradication of H. pylori. Despite the reduction in COX-2 expression after H. pylori eradication, expression of COX-2 in epithelial cells remained and strongly correlated with the extent of the chronic inflammatory cell infiltrate. The clinical implications of H. pylori-associated induction of COX-2 expression for patients on selective COX-2 inhibitors, in addition to the role of COX-2 in gastric carcinogenesis, deserve further study.     

Effects of cyclooxygenase-2 inhibitor on gastric acid secretion in Helicobacter pylori-infected C57BL/6 mice.

BACKGROUND: Helicobacter pylori-associated body gastritis inhibits gastric acid secretion. The aim of this study was to determine the effects of H. pylori infection on gastric acid secretion and further determine whether cyclooxygenase-2 was involved. METHODS: 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. Before, 12 and 24 weeks after inoculation, the gastric acid secretion, prostaglandin E2 (PGE2) levels in the gastric mucosa, and gastritis scores according to the updated Sydney system were determined. Immunohistochemical staining of COX-2 protein was also performed. RESULTS: No significant changes in gastric acid secretion, gastritis scores or PGE2 levels in the gastric mucosa were observed in uninfected groups with or without etodolac treatment during the study period. In the H. pylori-infected group without etodolac treatment, gastric acid secretion was significantly decreased with increases in PGE2 levels in the gastric mucosa 24 weeks after inoculation compared with the controls. Gastritis score for activity was significantly higher, and strong staining for COX-2 protein was observed in the H. pylori-infected group. In the H. pylori-infected group with etodolac treatment, PGE2 in the gastric mucosa was decreased and acid secretion was restored to the same level as in the control group. CONCLUSION: One of the mechanisms by which H. pylori infection inhibits gastric acid secretion is increased release of PGE2 produced by COX-2, which is induced by H. pylori infection.     

Update on the pathologic approach to the diagnosis of gastritis, gastric atrophy, and Helicobacter pylori and its sequelae

Biopsy sampling of the gastric mucosa at diagnostic endoscopy provides information that cannot be obtained otherwise. The most common indication for gastric biopsy is the need to know whether the patient is infected with Helicobacter pylori or not and whether the stomach is gastritic or not. Microscopic examination of gastric biopsy specimens gives, in addition to H. pylori status, information about the grade, extent, and topography of gastritis- and atrophy-related alterations in the gastric mucosa. This information provides further possibilities for the assessment of risk and likelihood of various gastric disorders. The presence of atrophy (loss of mucosal glands) results in failures in secretory functions of the corresponding mucosa and leads to errors in the homeostasis of normal gastric physiology. The grade of atrophy of the corpus mucosa linearly correlates with peak and maximal output of acid. The presence of advanced (moderate or severe) corpus atrophy indicates an extremely hypochlorhydric or achlorhydric stomach in which, for example, ordinary peptic ulcer is unlikely or impossible in spite of a possible H. pylori infection. Some well characterized and common topographic phenotypes of H. pylori gastritis and atrophic gastritis can be delineated as follows: Predominance or restriction of the H. pylori-related inflammation in antrum, in association with a nonatrophic corpus mucosa--of which phenotype is the most common--and with an increased risk of peptic ulcer disease, duodenal ulcer in particular ("duodenal ulcer phenotype" of gastritis); the presence of atrophic gastritis in corpus of the stomach ("corpus predominant gastritis"), which indicates a low risk of peptic ulcer and a reduction in the capacity of the patient to secrete acid; the occurrence of advanced atrophic gastritis and intestinal metaplasia multifocally in the stomach (advanced "multifocal atrophic gastritis"), which are features of a gastritis type and which also indicate a low acid secretion capacity and an increased risk of gastric neoplasias ("gastric cancer phenotype of gastritis"), suggesting a need for a careful exclusion of concomitant presence of small focal neoplastic or dysplastic lesions; and the presence of normal and healthy gastric mucosa, which indicates an extremely low risk of both peptic ulcer disease or gastric cancer and, therefore, is a finding of high clinical relevance. The presence of duodenal or gastric ulcer in conjunction with normal, healthy gastric mucosa suggests either aspirin or nonsteroidal antiinflammatory drugs to be the most likely cause of the ulcer.     

Healing of duodenal ulcers is not impaired by indomethacin or rofecoxib,the selective COX-2 inhibitor,in rats

BACKGROUND/AIM: Studies have demonstrated an important role for endogenous PG and NO in the healing of chronic gastric ulcers. We investigated the effects of COX and NOS inhibitors on the healing of duodenal ulcers, in comparison with gastric ulcers, in rats. METHODS: Gastric and duodenal ulcers were induced by serosal application of acetic acid (0.1 ml of 100% acetic acid) for 60 and 20 s, respectively. Indomethacin (a nonselective COX inhibitor) or rofecoxib (a selective COX-2 inhibitor) was given p.o. once daily for 14 days from 3 days after ulcer induction, while N(G)-nitro-L-arginine methyl ester (L-NAME: a nonselective NOS inhibitor) or aminoguanidine (a relatively selective iNOS inhibitor) was given s.c. twice daily during this period. RESULTS: Both gastric and duodenal ulcers induced by acetic acid healed spontaneously within 17 days to a minimal size. Daily administration of indomethacin or rofecoxib significantly delayed the healing of gastric but not duodenal ulcers. In contrast, the healing of both gastric and duodenal ulcers was delayed by repeated administration of either L-NAME or aminoguanidine. Ulceration markedly increased the PGE(2) content of the ulcerated mucosa in both the stomach and duodenum, and the increased PG biosynthetic response was inhibited by either indomethacin or rofecoxib in both tissues. The expression of both COX-2 and iNOS mRNAs was upregulated in the ulcerated mucosa of the stomach and duodenum. CONCLUSION: These results suggest that COX-2/PG is actively involved in the healing of gastric but not duodenal ulcers, although the mRNA for COX-2 is expressed in the duodenal mucosa after ulceration, as potently as in the gastric mucosa. In contrast, NO produced by both cNOS and iNOS plays a role in the healing of both gastric and duodenal ulcers.     

Increase in apoptosis and decrease in ornithine decarboxylase activity of the gastric mucosa in patients with atrophic gastritis and gastric ulcer after successful eradication of Helicobacter pylori

OBJECTIVE: Recent reports have shown that patients infected with Helicobacter pylori (H. pylori) have a higher risk of gastric cancer. However, the mechanism of this increased risk is still unclear. In the gastric mucosa, the size of a continuously renewed population of cells is determined by the rates of cell production and of cell loss. Ornithine decarboxylase (ODC) activity is elevated in various gastrointestinal cancers and serves as a marker of mucosal proliferative activity. Apoptosis occurs throughout the gut and is associated with cell loss. Both cell proliferation and cell loss have important roles in H. pylori-associated gastric carcinogenesis. Therefore, we investigated the effect of H. pylori eradication on ODC activity and apoptosis in the gastric mucosa of patients with atrophic gastritis and gastric ulcers. METHODS: Biopsy specimens of the gastric antrum were obtained at endoscopy from 17 H. pylori-positive gastric ulcers patients and 15 H. pylori-positive gastritis patients before and 4 wk after eradication therapy with amoxicillin, omeprazole, and a new anti-ulcer agent, ecabet sodium, and from 10 gastric ulcer patients in whom ulcer healed but H. pylori was left untreated. ODC activity and induction of apoptosis were determined immunohistochemically. RESULTS: H. pylori was successfully eradicated with the triple therapy in 12 (80%) of 15 gastritis patients and 13 (76%) of 17 gastric ulcer patients. ODC activity was present in the gastric mucosa in 21 (84%) patients before eradication but in only four (16%) patients after successful eradication (p = 0.0005). The apoptotic index increased significantly (p = 0.0006) from 4.2% +/- 0.4% before treatment to 7.4% +/- 0.5% after successful eradication. CONCLUSIONS: Successful eradication of H. pylori decreases mucosal ODC activity and increases apoptosis in the gastric mucosa. These findings indicate that by decreasing mucosal cell proliferation and increasing epithelial cell loss, H. pylori eradication may help decrease the subsequent risk of gastric cancer.     

环氧合酶-2表达与幽门螺杆菌相关性胃十二指肠疾病的研究

目的　探讨环氧合酶 2表达与幽门螺杆菌Helicobacterpylori ,H .pylori相关性胃十二指肠疾病的关系 ,并通过抗菌治疗评价根除H pylori感染对胃窦黏膜中COX 2表达的影响。方法　用免疫组化方法半定量检测 2 64例经胃镜和组织病理学检查患有十二指肠球部溃疡、胃溃疡、复合性溃疡、胃癌、单纯性慢性胃炎及胃黏膜正常者的胃窦黏膜COX 2蛋白的表达 ,比较H pylori感染与非感染者之间的差异。对检出的 3 5例H pylori的单纯慢性胃炎进行H pylori抗菌根除治疗 ,比较根除前后胃窦黏膜COX 2蛋白的表达变化。根据 2 0 0 0年 5月全国慢性胃炎研讨会共识意见 (江西 井冈山 )对胃黏膜炎症、活动性、异型增生、肠化生和H pylori密 ,度进行半定量测定。结果　胃黏膜表面上皮、腺上皮细胞和固有层间质细胞的浆中可见COX 2蛋白表达 ,但阳性染色细胞多集中在表层上皮。 2 53例中 ,14 3例H pylori者 (56 52 % )COX 2平均阳性细胞率显著高于 110例H pylori者 (43 48% ) ,(P =0 ) ,各疾病组H pylori患者的COX 2平均阳性细胞率均显著高于H pylori者 (P =0 ) ,各疾病组H pylori患者COX 2平均阳性细胞率也均显著高于正常对照组 (P <0 0 5)。 2 7例H pylori根除后的胃黏膜COX 2平均阳性细胞率明显下降 (P =0 ) ,但仍明显高于正     

The gastric transitional zones: neglected links between gastroduodenal pathology and helicobacter ecology

The gastric transitional zones are the junctional zones between the different types of mucosa: antral-body, body-cardia, and antrum-duodenum. In this article, the importance of the transitional zone in determining disease outcome, specifically duodenal ulcer, gastric ulcer, and possibly gastric cancer, is reviewed. Both gastric ulcers and duodenal ulcers are located immediately adjacent to the transitional zones. The transitional zones are dynamic rather than static areas. Local acid levels determine the behavior of Helicobacter pylori at the antral-body transitional zone and, as a consequence, the geographic distribution of gastritis in the stomach and the formation of duodenal ulcer and gastric ulcer. This review also explains that diffuse antral gastritis and multifocal atrophic gastritis are part of the same disease and not separate entities.     

Distribution and prevalence of Campylobacter pylori in the stomach

We investigated the distribution and prevalence of Campylobacter pylori in the stomach and duodenum. In this study, 500 biopsy specimens were obtained from 245 patients. In each case, biopsy specimens were taken from more than 2 sites. C. pylori was detected by culture, urease test and acridine-orange stain. C. pylori was not detected on the intestinal metaplasia, gastric cancer tissue and duodenal mucosa without gastric metaplasia. In 21% of cases, C. pylori was detected in only one site. Because of the patchy distribution of C. pylori, more than 2 biopsy specimens from different sites were needed to avoid sampling error. Detection rate of C. pylori was almost equal in antrum, angle and body as well as in male and female. H2 receptor antagonists did not affect the detection rate of C. pylori. According to the endoscopic diagnosis of the biopsied site, C. pylori was detected in 87% of gastric ulcer, 60% of duodenal ulcer (duodenal mucosa with gastric metaplasia), 73% of chronic gastritis and 62% of endoscopically normal gastric mucosa.     

Influence of gastritis on cyclooxygenase-2 expression before and after eradication of Helicobacter pylori infection

OBJECTIVES: Helicobacter pylori infection causes chronic gastritis and induces cyclooxygenase (COX)-2 expression. The relationship between gastritis and COX-2 expression is not well understood, especially long after the organism has been eradicated. We designed a study to elucidate this relationship. METHODS: Four endoscopic gastric biopsies from each of 118 H. pylori-infected subjects were assessed for COX-2 expression immunohistochemically, gastritis, by an updated Sydney System. In the 107 successfully eradicated subjects, the assessment was repeated once yearly, for 3 years. RESULTS: After successful eradication, COX-2 expression was reduced significantly regardless of site. Atrophy improved significantly and intestinal metaplasia improved but not in the antrum greater curvature. After 1 year COX-2 expression was not significantly different in the epithelia with and without intestinal metaplasia. Correlation between COX-2 expression and neutrophil score in the antrum (r = 0.214, P = 0.042) and inflammation in the corpus (r = 0.234, P = 0.025) disappeared after eradication. COX-2 expression correlated well with atrophy and metaplasia before and after eradication. No significant reduction in COX-2 or improvement in gastritis was found in subjects with eradication failure. CONCLUSION: H. pylori infection is associated with the enhancement of COX-2 expression in the gastric mucosa. Eradication therapy reduces COX-2 expression and hence may reduce the risk of cancer development.     

Ki-67表达及幽门螺杆菌感染在阿司匹林相关性胃黏膜病变中的作用

目的探讨Ki-67表达及幽门螺杆菌(Helicobacter pylori,H.pylori)在阿司匹林相关性胃黏膜病变中的作用。方法本组阿司匹林相关性胃黏膜病变患者共136例,根据胃镜下表现分为出血组、溃疡组和胃炎组;所有患者均应用快速尿素酶试验检测、病理组织学Giemsa染色及13C尿素呼气试验将136例阿司匹林相关性胃黏膜病变患者分为H.pylori感染阳性组和阴性组,应用免疫组织化学染色对各组病变的增殖细胞核抗原Ki-67表达进行检测。结果在正常胃黏膜上皮组织Ki-67无表达或呈弱阳性表达,平均染色积分为0.125±0.354。在阿司匹林相关性胃黏膜病变中,出血组胃黏膜上皮组织Ki-67平均染色积分为3.916±1.676;溃疡组胃黏膜上皮组织Ki-67平均染色积分为2.174±1.527;胃炎组胃黏膜上皮组织Ki-67平均染色积分为1.394±0.899。出血组胃黏膜上皮组织Ki-67平均染色积分显著高于溃疡组及胃炎组(P<0.05)。H.pylori感染阳性组胃黏膜上皮组织Ki-67平均染色积分为2.275±1.511,H.pylori感染阴性组胃黏膜上皮组织Ki-67平均染色积分为1.588±1.698。H.pylori感染阳性组胃黏膜上皮组织Ki-67染色积分明显高于H.pylori感染阴性组(P<0.05)。结论阿司匹林相关性胃黏膜病变组织中,阿司匹林和H.py-lori均可导致胃黏膜的损伤,促进胃黏膜上皮细胞增殖。