Gastric juice for the diagnosis of H pylori infection in patients on proton pump inhibitors

AIM： To determine the efficacy of gastric juice polymerase chain reaction （PCR） for the detection of H pylori infection in comparison with histology and gastric antral biopsy PCR in patients on a proton pump inhibitor （PPI）. METHODS： Eighty-five consecutive patients with dyspeptic symptoms were enrolled. Gastric biopsies for histology, PCR and gastric juice were collected at endoscopy for PCR of the H pylori urease C gene （ure C）. Sensitivity, specificity, positive predictive value （PPV）, negative predictive value （NPV）, accuracy, positive and negative likelihood ratio for PCR of gastric juice for the H pylori ure C gene was compared to histology and gastric antral biopsy H pylori ure C PCR in patients with and without PPI. RESULTS： Gastric juice PCR was positive in 66 （78%） patients. Histology showed H pylori associated gastritis in 57 （67%）. Gastric biopsy PCR was positive in 72 （85%）. In patients not taking PPI, the sensitivity, specificity, PPV, NPV, accuracy and positive and negative likelihood ratio for gastric juice PCR were 89%, 72%, 91%, 67%, 90%, 85%, 3.1 and 0.1 respectively. In patients on PPI these values were 86%, 100%%, 100%, 29%, 86%, 9.5 and 1.4, respectively. CONCLUSION： Gastric juice PCR for the diagnosis of H pylori infection has increased sensitivity compared to histology with PPI. The use of gastric juice PCR is recommended to confirm H pylori status in patients taking PPIs.     

Expression of cell-cycle related proteins in Helicobacter pylori gastritis and association with gastric carcinoma

Helicobacter pylori (H. pylori) infection is associated with changes in epithelial turnover, through their significance of these in gastric carcinogenesis is still controversial. The purpose of this study was to determine the influence of H. pylori infection on cell proliferation and the relation with the cell-cycle regulators, and finally to provide insights into the mechanism by which H. pylori may lead to gastric carcinogenesis. We investigated Ki-67, p53, p21(Waf1/Cip1), cyclin D1 expression in 55 patients with H. pylori gastritis, and compared the results with patients those of non-H. pylori gastritis patients (n=21), gastric adenocarcinoma patients (n=8) and samples with normal gastric mucosa (n=12). Gastric biopsies were histologically evaluated for inflammatory reaction, intestinal metaplasia and atrophy according to the Sydney system. Overexpression of Ki-67, p53, p21(Waf1/Cip1) and cyclin D1 was found in H. pylori gastritis patients (32.7%, 10.9%, 20.0% and 7.3%, respectively), whereas only scattered expression in cells in the neck region of the crypts, but no overexpression was found in gastric antral epithelial cells in biopsy specimens from patients with non-H. pylori gastritis and noninflammed mucosa. A significant relationship was found between the grade of H. pylori colonization and Ki-67, p53, p21(Waf1/Cip1) and cyclin D1 expression. Expression was significantly higher in patients with intestinal metaplasia with atrophy, whereas no overexpression was found in patients without intestinal metaplasia with atrophy (p=0.05). H. pylori infection is associated with increased cell proliferation, increased epithelial DNA damage, and atrophy, which might contribute to the development of gastric cancer. Even if the exact mechanism has not been elucidated yet, our results suggest that H. pylori infection acts as a cofactor in gastric carcinogenesis.     

Helicobacter pylori and mitogen-activated protein kinases regulate the cell cycle, proliferation and apoptosis in gastric epithelial cells

Background and Aims:  Helicobacter pylori infection activates mitogen-activated protein kinases (MAPK) and modulates cell proliferation and apoptosis. However, the relationship between H. pylori infection and MAPK signaling in controlling cell proliferation and apoptosis is not clear, nor has the role of MAPK on the gastric epithelial cell cycle and proliferation been established. Therefore, we investigated the effects of H. pylori infection and MAPK inhibition on these processes.
Methods:  Gastric epithelial cell lines (AGS and MKN45) were infected with H. pylori and/or treated with MAPK inhibitors. Cell cycle and apoptosis were measured by flow cytometry. Cell cycle proteins and proliferation were monitored by western blot and cell count, respectively.
Results:  Infection with H. pylori resulted in dose-dependent MAPK activation, cell cycle arrest, reduced proliferation and increased apoptosis. The effect of H. pylori and MAPK at various cell cycle checkpoints was noted: MEK1/2 and p38 inhibition increased H. pylori -induced cell cycle G₁ arrest, while JNK inhibition reduced G₁ arrest. MEK1/2 inhibition increased p21, p27 and cyclin E and JNK inhibition additionally increased cyclin D1 expression. Both inhibitors decreased cell proliferation. All inhibitors enhanced apoptosis after H. pylori infection. We also detected MAPK cross-talk in AGS cells: p38 and JNK inhibitors increased ERK activation. The p38 inhibitor increased JNK and the MEK1/2 inhibitor decreased JNK activation only during H. pylori infection.
Conclusions:  These results suggest H. pylori and MAPK differentially regulate the cell cycle, proliferation and apoptosis in gastric epithelial cells. The imbalance between H. pylori infection and MAPK activation likely contributes to the H. pylori -induced pathogenesis.     

幽门螺杆菌感染Balb/c 小鼠模型的建立及对N-甲基-N-亚硝基脲诱发胃癌的影响

目的建立一种稳定的造模周期短的幽门螺杆菌(Hp)感染模型,观察Hp对小鼠胃黏膜的损害程度,同时研究Hp感染是否促进亚硝基类化合物的致癌作用.方法 94只Balb/c小鼠分为4组.第1组单用N-甲基-N-亚硝基脲(MNU);第2、3组小鼠用灌胃法定植Hp,第3组小鼠加用MNU灌胃;第4组为正常对照.36周后处死全部小鼠,分别用尿素酶、Giemsa染色和微需氧细菌培养检测Hp定植;H-E染色进行鼠胃黏膜病理诊断.结果 Balb/c小鼠Hp定植率达93.9%.Hp单一处理组中度以上炎症占100.0%,其中萎缩性胃炎占20.0%;而Hp和MNU联合处理组中度以上炎症占100.0%,其中萎缩性胃炎占23.1%,不典型增生占42.3%和57.7%(胃体和胃窦),并发现2只小鼠有低分化腺癌,占7.1%.Hp处理组和Hp MNU联合处理组在炎症程度上与正常对照组相比,差异有统计学意义(P＜0.01).结论本实验成功建立了Hp感染小鼠模型,验证了Hp和胃癌的发生有高度相关性,证实Hp在协同MNU致癌性中的作用,提示胃癌的发生并非Hp感染单一因素的结果,而和多因素共同作用有关.     

Effect of Helicobacter pylori eradication on the outcome of reflux esophagitis and chronic gastritis in the elderly. A randomized, multicenter, eight-month study

BACKGROUND: The effect of Helicobacter pylori eradication on the clinical outcome of esophagitis in elderly patients is controversial. AIM: To evaluate the effect of H. pylori eradication on clinical outcome of esophagitis and on chronic gastritis and its activity. MATERIALS AND METHODS: Sixty-one symptomatic elderly patients with esophagitis and H. pylori infection were randomized into two groups. Group 1 (PPI-only, 30 patients) was treated with pantoprazole 40 mg daily for 2 months followed by pantoprazole 20 mg daily for a further 6 months; group 2 (PPI + eradication, 31 patients) was treated as group 1 plus a 1-week course of amoxicillin 1 g twice daily and clarithromycin 250 mg twice daily. Endoscopy with gastric biopsies, 13C-UBT and clinical visits were repeated after 2 and 8 months. RESULTS: After 8 months, the intention-to-treat H. pylori eradication rates were 19.2% in group 1 vs. 80.7% in group 2 (p < 0.0001). No differences between group 1 and group 2 were observed in symptoms improvement (77 vs. 77%, p = n.s.) and healing rates of esophagitis (92.3 vs. 88.5%, p = n.s.). A significant decrease in the prevalence of moderate/severe chronic gastritis (from 52.2 to 4.7%, p = 0.002) and its activity (from 38 to 4.7%, p = 0.02) was observed in the antrum of patients of group 2, and not in patients of group 1. While a nonsignificant reduction in the chronic gastritis activity (from 28.6 to 4.7%, p = 0.09) was observed in the corpus of the eradicated patients of group 2, conversely a significant worsening of the chronic gastritis activity was found in the corpus of group 1 patients (from 25 to 60%, p = 0.05). CONCLUSION: The eradication of H. pylori infection does not affect the clinical outcome of esophagitis, while it improves chronic gastritis and its activity in elderly patients on short- and long-term treatment with PPIs. These findings suggest that H. pylori infection should be eradicated in elderly patients with esophagitis who need maintenance treatment with PPI.     

Influence of proton pump inhibitors on gastritis diagnosis and pathologic gastric changes

AIM: To investigate the influence of proton pump inhibitors (PPIs) exposure on the diagnosis of Helicobacter pylori (H. pylori) gastritis and intestinal metaplasia.METHODS: Chronic PPI use is associated with masking of H. pylori infection. Patients with H. pylori infection are predisposed to gastric and duodenal ulcers, and long-term infection with this organism has been associated with gastric mucosal atrophy and serious long-term complications, such as gastric lymphoma and adenocarcinoma. Three hundred patients diagnosed with gastritis between January 2008 and April 2010 were included in our study. The computerized medical database of these patients was reviewed retrospectively in order to assess whether the type of gastritis diagnosed (H. pylori vs non-H. pylori gastritis) is influenced by PPI exposure. H. pylori density was graded as low, if corresponding to mild density following the Updated Sydney System, or high, if corresponding to moderate or severe densities in the Updated Sydney System.RESULTS: Patients were equally distributed between males and females with a median age at the time of diagnosis of 50 years old (range: 20-87). The histological types of gastritis were classified as H. pylori gastritis (n = 156, 52%) and non-H. pylori gastritis (n = 144, 48%). All patients with non-H. pylori gastritis had inactive chronic gastritis. Patients with no previous PPI exposure were more likely to be diagnosed with H. pylori gastritis than those with previous PPI exposure (71% vs 34.2%, P < 0.001). Intestinal metaplasia was more likely to be detected in the latter patients (1.4% vs 6.5%, P = 0.023). Multivariate analysis has also demonstrated that in the presence of previous PPI exposure (OR = 0.217, 95%CI: 0.123-0.385), GERD (OR = 0.317, 95%CI: 0.132-0.763, P = 0.01), alcohol intake (OR = 0.396, 95%CI: 0.195-0.804, P = 0.01), the detection of H. pylori was less likely. Chronic use of PPIs may mask H. pylori infections promoting the diagnosis of non-H. pylori gastritis and leads to a significant drop in H. pylori densities and to an increased risk of intestinal metaplasia.CONCLUSION: The use of PPIs masks H. pylori infection, promotes the diagnosis of non-H. pylori inactive chronic gastritis diagnosis, and increases the incidence of intestinal metaplasia.     

幽门螺杆菌感染与上胃肠道疾病

1982年Marshall和Mareen首次从慢性活动性胃炎患者的胃粘膜中分离出为幽门螺杆菌(Hp)。本文概括了Hp与上胃肠道疾病的关系，并评估其感染的治疗。现已确认Hp与4种上胃肠道疾病密切相关：(1)慢性胃炎；(2)消化性溃疡病；(3)胃癌；(4)胃粘膜相关淋巴样组织(MALT)淋巴瘤。Hp是慢性胃炎的主要病因，与消化性溃疡病的发生密切相关，Hp感染增加了胃腺癌发生的危险性，而且也涉及到胃MALT淋巴瘤发生的致病机理。Hp感染的治疗是以PPI、铋制剂以及RBC为基础的三联疗法，当三联疗法失败时则推荐四联疗法。四联疗法是传统的三联疗法(铋剂为基础的三联疗法)十PPI组成。     

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.     

Role of Helicobacter pylori in the pathogenesis of gastric carcinoma and progression of lymphoid nodules to lymphoma.

The pathology of gastritis associated with Helicobacter pylori infection is summarized. The literature is reviewed regarding the role of H pylori in the pathogenesis of gastric carcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. The potential mechanisms of gastric carcinogenesis include transformation of the gastric mucosa by metabolic products of H pylori, transformation of the host cell by incorporation of H pylori DNA and genotoxic effects of the inflammatory response to the organism. A model for gastric carcinogenesis is proposed in which H pylori causes cell proliferation, and the risk of DNA damage is increased, leading to inadequate repair and malignant transformation. Investigation of early gastric carcinomas concluded that two main pathways operated in gastric carcinogenesis, both starting from H pylori gastritis and leading to phenotypically variable gastric or intestinal tumour growth. The histological features and molecular genetics of MALT lymphoma are briefly reviewed. There is evidence that tumour cells of low grade B cell MALT lymphoma proliferate specifically in response to H pylori. This response is dependent on T cell activation by H pylori. A proposed model for the pathogenesis of MALT lymphoma postulates that B lymphocytes with a genetic change acquire a growth advantage resulting in a monoclonal proliferation in response to H pylori-activated T cells. Further genetic changes may result in escape from T cell dependency.     

Aggretin, a snake venom-derived endothelial integrin alpha 2 beta 1 agonist, induces angiogenesis via expression of vascular endothelial growth factor

Aggretin, a collagen-like alpha 2 beta 1 agonist purified from Calloselasma rhodostoma venom, was shown to increase human umbilical vein endothelial cell (HUVEC) proliferation and HUVEC migration toward immobilized aggretin was also increased. These effects were blocked by A2-IIE10, an antibody raised against integrin alpha 2. Aggretin bound to HUVECs in a dose-dependent and saturable manner, which was specifically inhibited by A2-IIE10, as examined by flow cytometry. Aggretin elicited significant angiogenic effects in both in vivo and in vitro angiogenesis assays, and incubation of HUVECs with aggretin activated phosphatidylinositol 3-kinase (PI3K), Akt, and extracellular-regulated kinase 1/2 (ERK1/2); these effects were blocked by A2-IIE10 or vascular endothelial growth factor (VEGF) monoclonal antibody (mAb). The angiogenic effect induced by aggretin may be via the production of VEGF because the VEGF level was elevated and VEGF mAb pretreatment inhibited Akt/ERK1/2 activation as well as the in vivo angiogenesis induced by aggretin. The VEGF production induced by aggretin can be blocked by A2-IIE10 mAb pretreatment. In conclusion, aggretin induces endothelial cell proliferation, migration, and angiogenesis by interacting with integrin alpha 2 beta 1 leading to activation of PI3K, Akt, and ERK1/2 pathways, and the increased expression of VEGF may be responsible for its angiogenic activity.     

Mucosal tumour necrosis factor alpha and interleukin-6 in patients with Helicobacter pylori associated gastritis.

The production of tumour necrosis factor alpha (TNF alpha) and interleukin-6 by human antral mucosa during short term culture in vitro has been measured by enzyme linked immunosorbent assay. TNF alpha and interleukin-6 concentrations in culture supernatants were significantly greater (p less than 0.001) in patients infected with Helicobacter pylori, all of whom had chronic gastritis, than in patients who were H pylori negative with histologically normal gastric mucosa. Among H pylori colonised patients, TNF alpha concentrations were significantly higher in those with active gastritis and neutrophil infiltration into the epithelium than in those with inactive gastritis. In contrast, interleukin-6 concentrations were raised in both active and inactive gastritis. This study shows that H pylori gastritis is associated with increased gastric mucosal production of TNF alpha and interleukin-6 and that the nature of the mucosal cytokine response varies with the immunohistology of the disease. Inflammatory cytokines generated locally within the gastric mucosa could be relevant to the gastric physiology of H pylori infection.     

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

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Tnfluence of various proton pump inhibitors on intestinal metaplasia in noneradicated Helicobacter pylori patients

AIM: Intestinal metaplasia (IM) is more often found in patients with Helicobacter pylori(H pylori) infection, while eradication of H pylori results in significant reduction in the severity and activity of chronic gastritis. We aimed to determine in patients with unsuccessful eradication of H pylori the role of various proton pump inhibitors (PPIs)having different mechanisms in the resolution of IM.METHODS: We confirmed endoscopically and pathohistologically (Sydney classification) the IM in 335 patients with gastritis before and after medication for eradication of H pylori(Maastricht Protocol 2002). H pylori infection was determined by using histology, urease test and culture. Control endoscopy and histology were done after 30 d and thereafter (within 1 year). Unsuccessful eradication was considered if only one of the three tests (histology, urease and culture) was negative after therapy protocol. We used omeprazole, pantoprazole,lansoprazole in therapy protocols (in combination with two antibiotics).RESULTS: We found no significant difference in resolution of IM by using different PPI between the groups of eradicated and noneradicated patients (P＜0.4821 and P＜0.4388,respectively).CONCLUSION: There is no significant difference in resolution of intestinal metaplasia by different proton pump inhibitors.     

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.     

Differential roles of interleukin-1beta and interleukin-8 in neutrophil transendothelial migration in patients with Helicobacter pylori infection

BACKGROUND: Little information is currently available on the contribution of locally generated inflammatory and chemotactic cytokines to endothelial cell activation and subsequent neutrophil transendothelial migration in patients with Helicobacter pylori (H. pylori)-associated gastritis. METHODS: The contents of interleukin (IL)-1beta and IL-8 in the organ culture supernatants of antral mucosal tissues were measured with an enzyme-linked immunosorbent assay. The effects of the endogenous IL-1beta and IL-8 in mucosal tissues on neutrophil adherence and transendothelial migration were investigated using an experimental model of human umbilical vein endothelial cells (HUVEC). RESULTS: The contents of IL-1beta and IL-8 in organ cultures of antral mucosal tissues were significantly higher in patients with H. pylori infection than in those without infection. The organ culture supernatants from H. pylori-positive patients induced the expression of intercellular adhesion molecule-1 mRNA in HUVEC with increased binding of neutrophils, and these stimulatory effects were inhibited when HUVEC were pretreated with a nuclear factor-kappaB inhibitor, MG-132. Moreover, neutrophil adherence to HUVEC induced by the supernatants decreased after preincubation with neutralizing anti-IL-1beta antibody. As compared with the supernatants from H. pylori-negative patients, the samples from H. pylori-positive patients exhibited a significantly higher chemotactic activity for neutrophils, which was inhibited almost completely by preincubation of the supernatants with anti-IL-8 antibody. CONCLUSIONS: Locally generated IL-1beta and IL-8 could coordinate with each other during the process of neutrophil infiltration into the gastric mucosa in patients with H. pylori infection.