Prevalence of Helicobacter pylori infection and gastric cancer precursor lesions in patients with dyspepsia

BACKGROUND: Helicobacter pylori infection has been considered to play significant role in gastric carcinogenesis, but only a minority of people who harbor this organism will develop gastric cancer. H. pylori infection first causes chronic non atrophic gastritis. Chronic non atrophic gastritis may evolve to atrophic gastritis and intestinal metaplasia and finally to dysplasia and adenocarcinoma. AIMS: To estimate the prevalence of H. pylori infection and the precancerous gastric lesions and their relationship, in patients with dyspeptic symptoms who underwent upper gastrointestinal endoscopy at a reference center in the central region of Rio Grande do Sul state, Brazil. METHODS: We analyzed gastric biopsies taken from corpus and antrum of patients who underwent upper gastrointestinal endoscopy for H. pylori detection, between 1994 and 2003. According to Sydney system, chronic non atrophic gastritis, atrophic gastritis and intestinal metaplasia were diagnosed by histological examination (H-E stain). The histological diagnoses were related to H. pylori infection status. RESULTS: Biopsies from 2,019 patients were included in the study. Patients mean age was 52 (+/-15) and 59% were female. Seventy six percent had H. pylori infection. Normal mucosa, chronic non atrophic gastritis, atrophic gastritis and intestinal metaplasia were diagnosed in 5%, 77%, 3% and 15%, respectively. The OR for any degree of gastric mucosa lesion in infected patients was 10 (CI95% 6.50 - 17%). The OR for infected patients had chronic non atrophic gastritis was 3 (CI95% 2,2 - 3,4). The OR for infected patients had atrophic gastritis or intestinal metaplasia was less than 1. CONCLUSIONS: The prevalence of H. pylori infection in this population was high (76%) and infected individuals had the probability 10 folds greater than non infected individuals to have any lesion of gastric mucosa. The prevalence of precancerous lesions was 77% for non atrophic chronic gastritis, 3% for atrophic gastritis and 15% for intestinal metaplasia. Infected patients had risk 3 folds greater than non-infected for the occurrence of non atrophic chronic gastritis. H. pylori infection did not show risk for occurrence of atrophic gastritis and intestinal metaplasia, suggesting that other risk factors should be involved in the carcinogenesis process.     

Coordinate increase of telomerase activity and c-Myc expression in Helicobacter pylori-associated gastric diseases

AIM: To detect the telomerase activity and c-Myc expression in gastric diseases and to examine the relation between these values and Helicobacter pylori (H pylori) as a risk factor for gastric cancer. METHODS: One hundred and seventy-one gastric samples were studied to detect telomerase activity using a telomerase polymerase chain reaction enzyme linked immunosorbent assay (PCR-ELISA), and c-Myc expression using immunohistochemistry. RESULTS: The telomerase activity and c-Myc expression were higher in cancers (87.69% and 61.54%) than in noncancerous tissues. They were higher in chronic atrophic gastritis with severe intestinal metaplasia (52.38% and 47.62%) than in chronic atrophic gastritis with mild intestinal metaplasia (13.33% and 16.67%). In chronic atrophic gastritis with severe intestinal metaplasia, the telomerase activity and c-Myc expression were higher in cases with H pylori infection (67.86% and 67.86%) than in those without infection (21.43% and 7.14%). c-Myc expression was higher in gastric cancer with H pylori infection (77.27%) than in that without infection (28.57%). The telomerase activity and c-Myc expression were coordinately up-regulated in H pylori infected gastric cancer and chronic atrophic gastritis with severe intestinal metaplasia. CONCLUSION: H pylori infection may influence both telomerase activity and c-Myc expression in gastric diseases, especially in chronic atrophic gastritis.     

Helicobacter pylori and gastric premalignant conditions.

A hypothetical sequence occurs in the stomach from H. pylori infection to premalignant conditions. This sequence is characterized by several well documented steps. First, the H. pylori infection seems to be the main course of chronic gastritis, and is seen to be associated with gastritis at least in 80% of the cases. Second, chronic gastritis tends to slowly progress to atrophy and intestinal metaplasia of the underlying mucosa in a great proportion of affected subjects, this progression of chronic gastritis to atrophy being, however, multifactorial in nature, and being obviously affected also by factors other than the H. pylori. Third, there occurs an increased risk of gastric cancer in atrophic stomach (atrophic gastritis) with intestinal metaplasia, this risk being dependent upon the extend and grade of atrophic and metaplastic alterations in the stomach. Thus, it can be suggested that the H. pylori infection may trigger a sequence which will finally result in a development of conditions that favour the cancer formation. Recent epidemiological observations support this view: gastric cancer tends to be common in populations in which the H. pylori infection and the gastritis are common and in which the people will be commonly infected already in childhood, or in young age.     

Expression of gastric cancer—associated MG7 antigen in gastric cancer,precancerous lesions and H.pylori—associated gastric diseases

AIM: To investigate the relationship between the antigen MG7 antigen expression and gastric cancer as well as precancerous condition; to study the relationship between the MG7 antigen expression and H. pyloriinfection in benign gastric lesions in order to find out the effect of H. pylori infection on the process of gastric cancer development.METHODS: The level of MG7 antigen expression was determined by immunohistochemical method in 383 gastric biopsied materials. The intestinal metaplasia was determined by histochemistry method. The H. pyloriinfection was determined by HE stain, PCR and ELISA in 291 specimens, among which only 34 cases of H. pylori-associated gastric lesions were followed up.RESULTS: The positive rate of MG7 expression in normal gastric mucosa, intestinal metaplasia, dysplasia and gastric cancer increased gradually in ascending order (P＜0.01). The positive rate of MG7 antigen expression in type Ⅲ intestinal metaplasia of gastric mucosa was higher than that of type Ⅰand Ⅱ intestinal metaplasia, being highly significant (P＜0.05).The positive rate of MG7 antigen expression in superficial gastritis, atrophic gastritis and gastric cancer increased gradually (11.9 %, 64.8 %, 91.2 %, P＜0.01). There was no significant difference between H.pylori-negative and H. pyloripositive intestinal metaplasia, atrophic gastritis and dysplasia of gastric epithelium in the positive rate of MG7 antigen expression. There was no expression of MG7 antigen in H. pylori-negative superficial gastritis. The positive rate of MG7 expression in H. pylori-positive superficial gastritis was 20.5 %, and the difference between them was significant (P＜0.05). During following up, one of the three H. pylori negative cases turned positive again, and its MG7 antigen expression turned to be stronger correspondingly. 3 of 31 H. pyloripositive cases were detected as early gastric cancer, among which one with "+++" MG7 antigen expression was diminished after H. pylori eradication.CONCLUSION: MG7 antigen expression is highly specific in gastric cancer and can be used as a good marker for screening of gastric cancer; type Ⅲ intestinal metaplasia, atrophic gastritis and dysplasia should be followed up and MG7 antigen expression has high clinical value in the dynamic follow-up study; although the positive -MG7 in positiveH. pylorisuperficial gastritis show benign morphology in features, there is still the potential risk of developing into gastric cancer, hence special attention should be paid to those showing increasing MG7 antigen expression.     

Gastric epithelial cell kinetics in the progression from normal mucosa to gastric carcinoma.

Increased epithelial cell proliferation is associated with an increased risk of adenocarcinoma and is associated with Helicobacter pylori infection. The aim of this study was to assess both gastric epithelial cell proliferation and the influence of H pylori infection on cell kinetics in the progression from normal mucosa to gastric carcinoma. One hundred and forty four subjects were assigned to study groups based on diagnosis and H pylori status: microscopically normal mucosa and H pylori negative (n = 28); chronic active gastritis and H pylori positive (n = 83); atrophic gastritis (n = 9); intestinal metaplasia (n = 19); gastric carcinoma (n = 12). Gastric antral epithelial cell proliferation was assessed using the in vitro bromodeoxyuridine immunohistochemical technique and expressed as the labelling index per cent (LI%). Subjects with chronic atrophic gastritis, intestinal metaplasia or gastric cancer have increased gastric epithelial cell proliferation compared with normal mucosa (LI% mean (SEM): 5.14 (0.6), 4.68 (0.3), 6.50 (0.5) v 3.08 (0.2), p < 0.001). This increase in gastric epithelial cell proliferation was not influenced by H pylori status. Gastritis associated with H pylori had an increased LI% compared with normal controls or subjects with H pylori negative gastritis (4.98 (0.2) v 3.08 (0.2), 3.83 (0.2), p < 0.01). H pylori infection although associated with an increased epithelial cell proliferation in subjects with chronic gastritis, does not influence the increased epithelial cell proliferation seen in subjects with precancerous lesions or gastric carcinoma. This is further evidence that H pylori may be an initiating step in gastric carcinogenesis.     

Prevention by bovine milk against Helicobacter pylori-associated atrophic gastritis through its adherence inhibition

BACKGROUND/AIMS: The effects of Helicobacter pylori infection on the development of atrophic gastritis and intestinal metaplasia in relation to lifestyle and diet and the effect of the bovine milk on H. pylori adherence to gastric antral mucosa were investigated. METHODOLOGY: H. pylori infection was investigated in 63 patients without endoscopic evidence of gastroduodenal disease. Presence of H. pylori infection was assessed by culture and histologic examination of antral and corpus biopsy samples. Grades of atrophic gastritis and intestinal metaplasia were judged with chromoendoscopy (Congo red-methylene blue test). Adherence of H. pylori was evaluated with scanning electron microscopic examination of antral mucosa in Mongolian gerbils. RESULTS: Cross-sectional analysis of lifestyle and diet showed that a high intake of bovine milk was significantly related to prevention of H. pylori infection and the developments of atrophic gastritis and intestinal metaplasia. H. pylori adherence to the gastric mucosa was inhibited by bovine milk in a dose-dependent manner. CONCLUSIONS: Bovine milk prevents the development of atrophic gastritis and intestinal metaplasia through its defense mechanisms against the attachment of H. pylori to the gastric mucosa.     

Association of Helicobacter pylori infection with atrophic gastritis and intestinal metaplasia

AIMS: To evaluate the effect of Helicobacter pylori infection and aging on atrophy and intestinal metaplasia of the gastric mucosa. METHODS: One hundred and sixty-three patients were divided into three age groups and underwent an upper gastrointestinal endoscopy where no esophagitis, peptic ulcers, or malignancies were detected. Two biopsy specimens were obtained from the anterior and posterior walls of the antrum and of the fundus. These were used to evaluate the grade of gastritis, bacterial culture and histologic evidence of H. pylori infection. RESULTS: Helicobacter pylori infection was found to be directly associated with an increased risk of gastritis grade (odds ratio (OR) = 90 (95% CI; 30-270)). An age of 60 years and older along with H. pylori infection was also strongly associated with an increased risk of atrophy (OR = 6.6, (95% CI; 2.9-15.2)); OR = 9.8, (95% CI; 2.7-35.4)), as was intestinal metaplasia of the gastric mucosa (OR = 5.5, (95% CI; 1.7-17.6)); OR = 7.9, (95% CI; 2.8-46.1)). The prevalence of atrophic gastritis increased with advancing age in H. pylori-infected patients, but no such phenomenon was observed in H. pylori-uninfected patients. The prevalence of intestinal metaplasia significantly increased with advancing age, irrespective of the presence of H. pylori infection. In addition, H. pylori uninfected female patients had a decreased risk of intestinal metaplasia. CONCLUSIONS: These results suggest that atrophic gastritis is not a normal aging process, but instead is likely to be the result of H. pylori infection, while intestinal metaplasia is caused by both the aging process and H. pylori infection. A decreased risk of intestinal metaplasia found in uninfected female subjects may partly explain the lower prevalence of gastric cancer in females than in males.     

胃黏膜病变演化过程中抗氧化蛋白Peroxiredoxin6的表达及其与幽门螺杆菌感染的关系

目的探讨胃黏膜病变演化过程中抗氧化蛋白Peroxiredoxin 6(Prx6)表达水平变化及其与幽门螺杆菌(H.pylori)感染的关系。方法根据组织形态学将104例临床内镜检查活检标本分为慢性浅表性胃炎(33例)、慢性萎缩性胃炎(25例)、肠上皮化生(32例)及异型增生(14例)4组。用免疫组织化学方法检测组织标本中Prx6的表达水平。用快速尿素酶试验及Warthin-Starry银染检测H.pylori感染。结果 Prx6在慢性浅表性胃炎、慢性萎缩性胃炎、肠上皮化生、异型增生组的阳性表达率分别为39.4%(13/33)、80.0%(20/25)、93.8%(30/32)、92.9%(13/14),过表达率分别为15.2%(5/33)、44.0%(11/25)、81.3%(26/32)、85.7%(12/14)。慢性浅表性胃炎、慢性萎缩性胃炎组H.pylori阳性者Prx6阳性表达率显著高于H.pylori阴性者(P<0.05),肠上皮化生组Prx6的表达在H.pylori阳性者和阴性者无显著差异(P>0.05)。结论在胃黏膜病变演化过程中,Prx6的表达随着胃黏膜病变的进展而增加,H.pylori在胃黏膜病变演化的早期阶段促进了Prx6的表达。     

Helicobacter pylori infection and early gastric cancer

BACKGROUND: Helicobacter pylori has recently been associated with an increased risk of gastric cancer. This study aimed to examine the association between H. pylori, histologic chronic gastritis, and intestinal metaplasia in early gastric cancers of different histologic types. STUDY: Seventy-four patients who were surgically diagnosed as having early gastric cancer were included in this study. All tissue specimens were obtained from patients by endoscopic biopsy and were classified histopathologically as intestinal-type early gastric cancer in 55 patients and diffuse-type early gastric cancer in 19 patients. RESULTS: H. pylori infection was found in 67 patients (90.5%) but not found in seven (9.5%). And the prevalence of H. pylori infection with nongastric cancer patients was also high (68.5%). There was no significant difference between the intestinal-type and the diffuse-type early gastric cancer in chronic active gastritis and atrophic chronic gastritis. Intestinal metaplasia was observed more frequently in patients with the intestinal-type than with the diffuse-type early gastric cancer (P = 0.0102). CONCLUSIONS: Infection with H. pylori has an important relationship to both histopathologic types of early gastric cancer.     

Helicobacter pylori and gastric cancer: correlation with gastritis, intestinal metaplasia, and tumour histology.

This study aimed to examine the association between Helicobacter pylori, histological gastritis, and intestinal metaplasia in gastric cancers of different histological types. A total of 169 gastrectomy specimens received in one pathology department were studied. Altogether 156 were adenocarcinomas (intestinal type 87, diffuse type 50, mixed type 19). Gastritis occurred in 137 of 163 body specimens (84%) and in 126 of 131 antral specimens (96%). Its presence was unrelated to tumour histology. Atrophic gastritis was more common in both body and antral mucosa in intestinal type compared with diffuse type carcinoma. This was also true for intestinal metaplasia of the body, but not of the antral mucosa. H pylori was present in 101 of 163 (62%) body specimens and 56 of 131 (43%) antral specimens. In intestinal type carcinoma, H pylori was found in 52/84 (62%) body specimens and in 24/70 (34%) antral specimens, while the corresponding figures for diffuse type carcinoma were 29/48 (60%) and 17/38 (45%) respectively. Tumour histology therefore had no influence on the occurrence of H pylori. Tumour site had no effect on the presence or absence of gastritis, atrophic changes, intestinal metaplasia, or H pylori. While both H pylori and gastritis are associated with gastric cancer, the association is unrelated to tumour histology and may not be a causal one.     

幽门螺杆菌相关性胃炎和胃癌前期病变的发病机制

幽门螺杆菌（H．pylori）感染诱发胃黏膜的炎症反应是引起一切病变的基础，并且它在慢性胃炎→萎缩性胃炎→胃黏膜肠上皮化生→不典型增生→胃癌的演变过程中至始至终起作用，因此H．priori相关性胃炎是H．priori致病的启动因子。H．priori感染可引起胃黏膜局部固有和获得性免疫异常，炎症介质的释放、ROS和NO含量的异常，胃上皮细胞增殖与凋亡失衡，端粒酶及相关基因表达异常。这些因素综合作用引起胃黏膜炎症，并且由其发展为胃癌前病变，最终导致胃癌发生。     

Diagnosis of Helicobacter pylori infection in patients with atrophic gastritis: comparison of histology, 13C-urea breath test, and serology

BACKGROUND: Atrophic gastritis, a risk factor for gastric cancer, is a late consequence of Helicobacter pylori infection in approximately one-third of the infected patients. It has been suggested that gastric cancer would develop less frequently if H. pylori were eradicated. However, the prevalence of H. pylori infection may be underestimated in patients with atrophic gastritis and intestinal metaplasia if only biopsy-based diagnostic methods are used. METHODS: We compared histology, 13C-urea breath test (13C-UBT), and serology in H. pylori diagnostics in 50 male patients with atrophic corpus gastritis. RESULTS: H. pylori was detected in 15 (30%) patients by histology and in 14 (28%) by 13C-UBT, whereas increased serum antibody levels indicating H. pylori infection were found in 41 (82%) patients (P < 0.0001 between serology and both histology and 13C-UBT). H. pylori infection was associated with atrophic corpus gastritis in 84% of the present patients (in one patient with normal antibody titres H. pylori was defined histologically). CONCLUSIONS: H. pylori infection would have been missed in most patients with atrophic gastritis without the analysis of H. pylori antibodies. Therefore, in patients with atrophic gastritis, the use of serology is encouraged in diagnosing H. pylori infection.     

Antral-type mucosa in the gastric incisura, body, and fundus (antralization): a link between Helicobacter pylori infection and intestinal metaplasia?

OBJECTIVES: Helicobacter pylori is a carcinogen; gastric carcinoma involves a multistep process from chronic gastritis to atrophy, intestinal metaplasia, and dysplasia. The aims of this study were to determine the types of mucosa at different gastric sites in H. pylori-infected and uninfected patients, and whether the presence of antral-type mucosa in the incisura, body, and fundus is associated with gastric atrophy and intestinal metaplasia. METHODS: Two hundred and sixty-eight patients with dyspepsia were enrolled. Eight biopsies (i.e., antrum x3, body x2, fundus x2, and incisura x1) were obtained. One antral biopsy was used for the CLO-test. Three (each from the antrum, body, and fundus) were cultured. The remaining biopsies were examined histologically according to the updated Sydney System after staining with hematoxylin and eosin and Giemsa. A validated serological test was also applied. RESULTS: Overall, 113 (42%) patients were infected with H. pylori. At the incisura, antral-type mucosa was more prevalent in infected than in uninfected patients (84% vs. 18%; odds ratio [OR] = 23.9, 95% confidence interval [CI] 12.5-45.8; p<0.001). Atrophic gastritis and intestinal metaplasia at the incisura was present in 19.5% and 13.3%, respectively, of infected, and 4.5% and 3.2%, respectively, of uninfected patients (both p<0.01). Moreover, atrophic gastritis at the incisura was associated with the presence of antral-type mucosa at the site (termed antralization); the prevalence of atrophic gastritis was 19.5% (24/123) in the presence of antralization, whereas the rate was 2.1% (3/145) without antralization (OR = 11.4, 95% CI 3.4-39.2; p<0.001). Similarly, at the incisura, 16.3% (20/123) of "antralized" cases and 1.4% (2/145) of "unantralized" cases had intestinal metaplasia (OR = 13.8, 95% CI, 3.2-60.7; p<0.001). The association between antralization at gastric body and fundus also appeared to be associated with atrophic gastritis and intestinal metaplasia at these sites. CONCLUSIONS: Atrophic gastritis and intestinal metaplasia occurs predominantly at the gastric antrum and incisura with H. pylori infection. Antralization of the gastric incisura is a common event in H. pylori-infected patients, and appears to be associated with an increased risk of atrophic gastritis and intestinal metaplasia.     

慢性胃炎胃黏膜细胞DNA含量和增殖活性的流式细胞仪检测

背景慢性萎缩性胃炎是一种胃癌癌前状态,研究表明正常胃黏膜、癌前病变和胃癌细胞的DNA含量随病变的进展而逐渐增高。目的应用流式细胞仪检测慢性胃炎胃黏膜细胞的DNA含量和增殖活性,探讨两者在慢性胃炎发生、发展过程中的临床意义。方法选取90例经胃镜检查诊断为慢性胃炎者的胃黏膜活检标本,制备单细胞悬液,应用流式细胞仪进行细胞DNA含量和增殖活性检测。结果所有慢性胃炎胃黏膜细胞的DNA倍体类型均为二倍体,但慢性萎缩性胃炎和慢性萎缩性胃炎伴肠化生胃黏膜细胞的增殖指数(PI)较慢性非萎缩性胃炎显著增高(P<0.05)。除慢性非萎缩性胃炎外,其余慢性胃炎组幽门螺杆菌(H.pylori)阳性患者胃黏膜细胞的PI值均较阴性患者显著增高(P<0.05)。结论慢性萎缩性胃炎和H.pylori阳性慢性胃炎胃黏膜细胞的增殖活性显著增高。应用流式细胞仪检测胃黏膜细胞的DNA含量和增殖活性,也许能成为胃癌癌前状态和癌前病变病理诊断的参考指标。     

Helicobacter pylori infection, glandular atrophy and intestinal metaplasia in superficial gastritis, gastric erosion, erosive gastritis, gastric ulcer and early gastric cancer

AIM: To evaluate the histological features of gastric mucosa, including Helicobacter pylori infection in patients with early gastric cancer and endoscopically found superficial gastritis, gastric erosion, erosive gastritis, gastric ulcer. METHODS: The biopsy specimens were taken from the antrum, corpus and upper angulus of all the patients. Giemsa staining, improved toluidine-blue staining, and Hpylori-specific antibody immune staining were performed as appropriate for the histological diagnosis of H pylori infection. Hematoxylin-eosin staining was used for the histological diagnosis of gastric mucosa inflammation, gastric glandular atrophy and intestinal metaplasia and scored into four grades according to the Updated Sydney System. RESULTS: The overall prevalence of H pylori infection in superficial gastritis was 28.7%, in erosive gastritis 57.7%, in gastric erosion 63.3%, in gastric ulcer 80.8%, in early gastric cancer 52.4%. There was significant difference (P<0.05), except for the difference between early gastric cancer and erosive gastritis. H pylori infection rate in antrum, corpus, angulus of patients with superficial gastritis was 25.9%, 26.2%, 25.2%, respectively; in patients with erosive gastritis 46.9%, 53.5%, 49.0%, respectively; in patients with gastric erosion 52.4%, 61.5%, 52.4%, respectively; in patients with gastric ulcer 52.4%, 61.5%, 52.4%, respectively; in patients with early gastric cancer 35.0%, 50.7%, 34.6%, respectively. No significant difference was found among the different site biopsies in superficial gastritis, but in the other diseases the detected rates were higher in corpus biopsy (P<0.05). The grades of mononuclear cell infiltration and polymorphonuclear cell infiltration, in early gastric cancer patients, were significantly higher than that in superficial gastritis patients, lower than that in gastric erosion and gastric ulcer patients (P<0.01); however, there was no significant difference compared with erosive gastritis. The grades of mucosa glandular atrophy and intestinal metaplasia were significantly highest in early gastric cancer, lower in gastric ulcer, the next were erosive gastritis, gastric erosion, the lowest in superficial gastritis (P<0.01). Furthermore, 53.3% and 51.4% showed glandular atrophy and intestinal metaplasia in angular biopsy specimens, respectively; but only 40.3% and 39.9% were identified in antral biopsy, and 14.1% and 13.6% in corpus biopsy; therefore, the angulus was more reliable for the diagnosis of glandular atrophy and intestinal metaplasia compared with antrum and corpus (P<0.01). The positivity rate of glandular atrophy and intestinal metaplasia of superficial gastritis with H pyloripositivity was 50.7%, 34.1%; of erosive gastritis 76.1%, 63.0%; of gastric erosion 84.8%, 87.8%; of gastric ulcer 80.6%, 90.9%; and of early gastric cancer 85.5%, 85.3%, respectively. The positivity rate of glandular atrophy and intestinal metaplasia of superficial gastritis with H pylorinegativity was 9.9%, 6.9%; of erosive gastritis 42.5%, 42.1%; of gastric erosion 51.1%, 61.9%; of gastric ulcer 29.8%, 25.5%; and of early gastric cancer 84.0%, 86.0%, respectively. The positivity rate of glandular atrophy and intestinal metaplasia of superficial gastritis, erosive gastritis, gastric erosion, and gastric ulcer patients with H pylon positivity was significantly higher than those with H pylori negativity (P<0.01); however, there was no significant difference in patients with early gastric cancer with or without H pylori infection. CONCLUSION: The progression of the gastric pre-cancerous lesions, glandular atrophy and intestinal metaplasia in superficial gastritis, gastric erosion, erosive gastritis and gastric ulcer was strongly related to H pylori infection. In depth studies are needed to evaluate whether eradication of H pylori infection will really diminish the risk of gastric cancer.     

Helicobacter pylori gastritis in Africa

* Helicobacter pylori gastritis progresses to gland loss and intestinal metaplasia in a considerable proportion of colonized subjects. * The progression to atrophic gastritis is a slow process, occurring with an incidence of 1-2% per year. * The progression of chronic H. pylori gastritis is the same in Africa as in Europe and South America. * This supports the concept of H. pylori as a causative factor of pre-neoplastic conditions of the gastric mucosa; other factors must play a modulating role in the progression to cancer. H. pylori gastritis may progress to atrophic gastritis and lead to the development of intestinal metaplasia, dysplasia and eventually gastric cancer in a minority of subjects. The available data on the kinetics of H. pylori gastritis are limited, but nevertheless very consistent. They suggest that the progression to gland loss or atrophic gastritis among H. pylori-positive subjects occurs at a rate of 1-2% per year. As H. pylori gastritis usually persists for life, a considerable proportion of H. pylori-positive subjects thus eventually show signs of gastric gland loss. The majority of these subjects progress to intestinal metaplasia. Despite these consistent findings in different areas of the world, the incidence of gastric cancer is only moderately related to the prevalence of H. pylori. An example is the so-called African enigma, referring to a low incidence of gastric cancer in certain countries of Africa, despite a high prevalence of H. pylori in all age groups. This is not due to differences in progression to atrophic gastritis; other yet unidentified factors therefore must play a role.     

Effect of Helicobacter pylori infection and its eradication on cell proliferation, DNA status, and oncogene expression in patients with chronic gastritis.

BACKGROUND: Helicobacter pylori, the main cause of chronic gastritis, is a class I gastric carcinogen. Chronic gastritis progresses to cancer through atrophy, metaplasia, and dysplasia. Precancerous phenotypic expression is generally associated with acquired genomic instability. AIM: To evaluate the effect of H pylori infection and its eradication on gastric histology, cell proliferation, DNA status, and oncogene expression. METHODS/SUBJECTS: Morphometric and immunohistochemical techniques were used to examine gastric mucosal biopsy specimens from eight controls, 10 patients with H pylori negative chronic gastritis, 53 with H pylori positive chronic gastritis, and 11 with gastric cancer. RESULTS: All patients with chronic gastritis were in a hyperproliferative state related to mucosal inflammation, regardless of H pylori infection. Atrophy was present in three of 10 patients with H pylori negative chronic gastritis and in 26 of 53 with H pylori positive chronic gastritis, associated in 18 with intestinal metaplasia. DNA content was abnormal in only 11 patients with atrophy and H pylori infection; eight of these also had c-Myc expression, associated in six cases with p53 expression. Fifty three patients with H pylori positive chronic gastritis were monitored for 12 months after antibiotic treatment: three dropped out; infection was eradicated in 45, in whom cell proliferation decreased in parallel with the reduction in gastritis activity; atrophy previously detected in 21/45 disappeared in five, regressed from moderate to mild in nine, and remained unchanged in seven; complete metaplasia disappeared in 4/14, and markers of genomic instability disappeared where previously present. In the five patients in whom H pylori persisted, atrophy, metaplasia, dysplasia, and markers of genomic instability remained unchanged. CONCLUSIONS: Chronic H pylori infection seems to be responsible for genomic instability in a subset of cases of H pylori positive chronic atrophic gastritis; eradication of H pylori infection can reverse inflammation and the related atrophy, metaplasia, and genomic instability.     

Effect of Helicobacter pylori infection on gastric epithelial proliferation in progression from normal mucosa to gastriccarcinoma

ＥｆｅｃｔｏｆＨｅｌｉｃｏｂａｃｔｅｒｐｙｌｏｒｉｉｎｆｅｃｔｉｏｎｏｎｇａｓｔｒｉｃｅｐｉｔｈｅｌｉａｌｐｒｏｌｉｆｅｒａｔｉｏｎｉｎｐｒｏｇｒｅｓｓｉｏｎｆｒｏｍｎｏｒｍａｌｍｕｃｏｓａｔｏｇａｓｔｒｉｃｃａｒｃｉｎｏｍａＬＩＵＷｅｎＺｈｏｎ...     

胃黏膜细胞线粒体DNA不稳定及核内整合与幽门螺杆菌感染有关

目的：线粒体DNA（mtDNA）因缺乏组蛋白保护，且损伤修复系统不健全，容易为幽门螺杆菌（Hp）相关胃炎中氧自由基的重要靶点，为此探讨胃黏膜细胞线粒体DNA不稳及核内整合与Hp感染的关系。方法：采用PCR和Giemsa染色检测Hp；采用限制性片段多态性（PCR－SSCP）和原位杂交方法检测胃黏膜细胞线粒体DNA微卫星不稳定（mtMSI）及核内mtDNA序列。结果：30例胃癌检出mtMSI11例（36．7％），15例肠化中有2例（13．3％），10例异型增生中有2例，10例萎缩性胃炎中有1例检出mtMSI。胃癌细胞核内mtDNA序列的检出率为20．0％（6／30），异型增生为1／10例，肠上皮化生为6．7％（1／15），萎缩性胃炎为1／10例，胃黏膜细胞mtMSI及核内mtDNA序列的检出率在Hp感染组（12／39，8／39）显著高于非Hp感染组（4／36，1／36，P＜0．05）。虽cagA^ 组mtMSI及核内mtDNA序列检出率（10／25，6／25）高于cagA^-组（2／14，2／14），但两组mtMSI及核内mtDNA序列检出率比较，差异并无显著性（P＞0．05）。结论：胃黏膜细胞mtMSI及mtDNA序列核内整合可能与Hp感染有关，并参与胃癌的发生。     

幽门螺杆菌及胃粘膜肠上皮化生与CD_(44)V_6表达的关系

目的　探讨幽门螺杆菌 (Hp)感染及慢性萎缩性胃窦炎伴肠上皮化生与CD4 4V6表达程度之间的关系。方法　以单克隆抗体及免疫组化技术等方法对Hp阴性单纯慢性胃炎、Hp阴性萎缩性胃炎伴肠上皮化生、Hp阳性萎缩性胃窦炎伴肠上皮化生、胃窦腺癌的胃镜下活检组织标本进行测定分析。结果　在Hp阴性单纯性胃炎组粘膜上皮未见CD4 4V6表达 ,Hp阴性萎缩性胃窦炎伴肠上皮化生、Hp阳性萎缩性胃窦炎伴肠上皮化生、胃窦腺癌各组CD4 4V6表达程度依次逐渐升高 ,各组之间比较差异有显著性 (P <0 .0 5 )。结论　CD4 4V6的表达可能是上皮细胞癌前病变出现的早期生物学信号 ,肠上皮化生细胞可能诱导CD4 4V6的表达 ,而Hp感染则有促进这种诱导表达的作用。