The Effect of Class II Major Histocompatibility Complex Expression on Adherence of Helicobacter pylori and Induction of Apoptosis in Gastric Epithelial Cells: A Mechanism for T Helper Cell Type 1–mediated Damage

Helicobacter pylori infection is associated with gastric epithelial damage, including apoptosis, ulceration, and cancer. Although bacterial factors and the host response are believed to contribute to gastric disease, no receptor has been identified that explains how the bacteria attach and signal the host cell to undergo apoptosis. Using H. pylori as “bait” to capture receptor proteins in solubilized membranes of gastric epithelial cells, class II major histocompatibility complex (MHC) molecules were identified as a possible receptor. Signaling through class II MHC molecules leading to the induction of apoptosis was confirmed using cross-linking IgM antibodies to surface class II MHC molecules. Moreover, binding of H. pylori and the induction of apoptosis were inhibited by antibodies recognizing class II MHC. Since type 1 T helper cells are present during infection and produce interferon (IFN)-γ, which increases class II MHC expression, gastric epithelial cell lines were exposed to H. pylori in the presence or absence of IFN-γ. IFN-γ increased the attachment of the bacteria as well as the induction of apoptosis in gastric epithelial cells. In contrast to MHC II–negative cell lines, H. pylori induced apoptosis in cells expressing class II MHC molecules constitutively or after gene transfection. These data describe a novel receptor for H. pylori and provide a mechanism by which bacteria and the host response interact in the pathogenesis of gastric epithelial cell damage.     

Immunization of Mice with Urease Vaccine Affords Protection against Helicobacter pylori Infection in the Absence of Antibodies and Is Mediated by MHC Class II–restricted Responses

We examined the roles of cell- and antibody-mediated immunity in urease vaccine–induced protection against Helicobacter pylori infection. Normal and knockout mice deficient in major histocompatibility complex (MHC) class I, MHC class II, or B cell responses were mucosally immunized with urease plus Escherichia coli heat-labile enterotoxin (LT), or parenterally immunized with urease plus aluminum hydroxide or a glycolipid adjuvant, challenged with H. pylori strain X47-2AL, and H. pylori organisms and leukocyte infiltration in the gastric mucosa quantified. In an adjuvant/route study in normal mice, there was a direct correlation between the level of protection and the density of T cells recruited to the gastric mucosa. In knockout studies, oral immunization with urease plus LT protected MHC class I knockout mice [β₂-microglobulin (−/−)] but not MHC class II knockout mice [I-A^b (−/−)]. In B cell knockout mice [μMT (−/−)], vaccine-induced protection was equivalent to that observed in immunized wild-type (+/+) mice; no IgA⁺ cells were detected in the stomach, but levels of CD4⁺ cells equivalent to those in the wild-type strain (+/+) were seen. These studies indicate that protection of mice against H. pylori infection by immunization with the urease antigen is dependent on MHC class II–restricted, cell-mediated mechanisms, and antibody responses to urease are not required for protection.     

Lansoprazole Novel Effector Sites Revealed by Autoradiography: Relation to Helicobacter pylori, Colon, Esophagus and Others

Lansoprazole uptake sites by two kinds of autoradiographic procedures were compared with recent literature. The uptake sites have been seen in the Helicobacter pylori, colonic epithelial cells, inflammatory cells, peripheral autonomic nerves and enterochromaffinlike cells as well as gastric parietal cells. Each uptake sites corresponded to the reported localization of P-type ATPase or acidic compartment.     

Proton pump inhibitor-amoxicillin-clarithromycin versus proton pump inhibitor-amoxicillin-metronidazole as first-line Helicobacter pylori eradication therapy

The aim of this study was to compare the efficacy and tolerability of the first-line Helicobacter pylori (H. pylori) eradication regimen composed of proton pump inhibitor, clarithromycin, and amoxicillin, with those of a regimen composed of proton pump inhibitor, metronidazole, and amoxicillin. Data of patients, who were administered the first-line H. pylori eradication regimen at Tokyo Medical Center between 2008 and 2011, were reviewed. All patients had H. pylori gastritis without peptic ulcer disease. The 7-day triple regimen composed of lansoprazole, clarithromycin, and amoxicillin was administered to 55 patients, and that composed of omeprazole, metronidazole, and amoxicillin was administered to 55 patients. Intention-to-treat and per-protocol eradication rates were 74.5 and 80.4%, respectively, for the regimen of lansoprazole, clarithromycin, and amoxicillin, whereas the corresponding rates were 96.4 and 100%, respectively, for the regimen of omeprazole, metronidazole, and amoxicillin. In conclusion, first-line H. pylori eradication therapy composed of omeprazole, metronidazole, and amoxicillin was significantly more effective than that composed of lansoprazole, clarithromycin, and amoxicillin, without differences in tolerability.     

Case-control study of association of eosinophilic gastrointestinal disorders with Helicobacter pylori infection in Japan

Recent studies have suggested that decrease in Helicobacter pylori infection may predispose to allergic diseases. However, there are few reports of the relationships of eosinophilic gastrointestinal disorders (EGIDs), especially eosinophilic gastroenteritis (EGE), with H. pylori infection. We investigated the possible influence of H. pylori infection on EGIDs in Japanese patients. We performed a case-control study to investigate the prevalence of H. pylori infection in patients with EGIDs. Eighteen with eosinophilic esophagitis (EoE) and 22 with EGE were enrolled. For each patient, 3 age- and gender-matched normal controls (n = 120) were randomly selected from a population who received a medical check-up between April 2010 and December 2011 at the Shimane Institute of Health Science. The mean ages of the EoE and EGE patients were 50.9 ± 17 and 49.2 ± 20 years, respectively. Males were more frequently seen in the EoE group, while there was no significant gender difference in regard to EGE. Of the patients with EoE, 22.3% were infected with H. pylori, as compared to 55.5% of their age- and sex-matched normal controls. The odds ratio for EoE patients to have an H. pylori infection was 0.22 (p<0.05). In addition, 22.7% of the patients with EGE and 48.5% of their matched controls were infected with H. pylori, with odds ratio for EGE patients to have an H. pylori infection shown to be 0.31 (p<0.05). In conclusion, the prevalence of H. pylori infection was significantly lower in EGE and EoE patients in Japan as compared to normal control subjects.     

Improvement of reflux symptom related quality of life after Helicobacter pylori eradication therapy

The relationship between Helicobacter pylori (H. pylori) eradication therapy and the risk of developing gastroesophageal reflux disease (GERD) is controversial. We investigated the influence of H. pylori eradication on the risk of GERD by focusing on the quality of life (QOL) and evaluating reflux symptoms. Patients with H. pylori infection were administered triple therapy for H. pylori eradication. At 3 months and 1 year after the eradication therapy, surveys were conducted to determine the health-related QOL by quality of life in reflux and dyspepsia-Japanese version, (QOLRAD-J) and the severity of GERD symptoms by Carlsson-Dent questionnaire (CDQ). Forty patients were included in the analysis. Although no significant changes of these scores were apparent 3 months after H. pylori eradication, the QOLRAD-J and CDQ scores were significantly improved after 1 year. The degree of improvement was even more marked in cases with initially low scores. In conclusion, improved GERD-related QOL and reflux symptoms were noted 1 year after H. pylori eradication therapy. In addition, the degree of improvement was more marked in cases with severe reflux symptoms.     

Circulating insulin-like growth factors in patients infected with Helicobacter pylori

OBJECTIVES: The level of insulin-like growth factors (IGFs) and their binding proteins may change in acutely ill humans. The aim of this work was to examine the changes in the IGF system in patients suffering from infection induced by Helicobacter pylori (H. pylori). DESIGN AND METHODS: The serum concentrations of IGF-I, IGF-II and cortisol were measured by radioimmunoassay. IGFBP patterns were characterized by ligand-affinity blotting, and a lectin-binding assay was used to investigate the possible changes in the glycocomponent of IGFBP-3. RESULTS: Both IGF-I and IGF-II concentrations were significantly lower in patients with H. pylori infection (P < 0.001 for IGF-I and P = 0.016 for IGF-II) compared to healthy individuals, whereas the level of cortisol was significantly elevated in analyzed patients (P < 0.001). Autoradiography demonstrated the increased presence of IGFBP-2 and IGFBP-1, together with a decreased level of IGFBP-3. CONCLUSIONS: The circulating IGF/IGFBP system is altered in patients infected with H. pylori. The increased level of cortisol suggests the involvement of the hypothalamic/pituitary/adrenal axis that stimulates the elevation of blood glucose, probably in coordination with decreased IGF activity to minimize anabolic metabolism.     

Helicobacter pylori modulates the T helper cell 1/T helper cell 2 balance through phase-variable interaction between lipopolysaccharide and DC-SIGN

The human gastric pathogen Helicobacter pylori spontaneously switches lipopolysaccharide (LPS) Lewis (Le) antigens on and off (phase-variable expression), but the biological significance of this is unclear. Here, we report that Le+ H. pylori variants are able to bind to the C-type lectin DC-SIGN and present on gastric dendritic cells (DCs), and demonstrate that this interaction blocks T helper cell (Th)1 development. In contrast, Le- variants escape binding to DCs and induce a strong Th1 cell response. In addition, in gastric biopsies challenged ex vivo with Le+ variants that bind DC-SIGN, interleukin 6 production is decreased, indicative of increased immune suppression. Our data indicate a role for LPS phase variation and Le antigen expression by H. pylori in suppressing immune responses through DC-SIGN.     

Changes in 12-Year First-Line Eradication Rate of Helicobacter pylori Based on Triple Therapy with Proton Pump Inhibitor,Amoxicillin and Clarithromycin

A triple therapy based on a proton pump inhibitor (PPI), amoxicillin (AMPC), and clarithromycin (CAM) is recommended as a first-line therapy for Helicobacter pylori (H. pylori) eradication and is widely used in Japan. However, a decline in eradication rate associated with an increase in prevalence of CAM resistance is viewed as a problem. We investigated CAM resistance and eradication rates over time retrospectively in 750 patients who had undergone the triple therapy as first-line eradication therapy at Nagoya City University Hospital from 1995 to 2008, divided into four terms (Term 1: 1997–2000, Term 2: 2001–2003, Term 3: 2004–2006, Term 4: 2007–2008). Primary resistance to CAM rose significantly over time from 8.7% to 23.5%, 26.7% and 34.5% while the eradication rate decreased significantly from 90.6% to 80.2%, 76.0% and 74.8%. Based on the PPI type, significant declines in eradication rates were observed with omeprazole or lansoprazole, but not with rabeprazole. A decrease in the H. pylori eradication rate after triple therapy using a PPI + AMPC + CAM has been acknowledged, and an increase in CAM resistance is considered to be a factor. From now on, a first-line eradication regimen that results in a higher eradication rate ought to be investigated.     

Comparative evaluation of 3 selective media for primary isolation of Helicobacter pylori from gastric biopsies under routine conditions

This study evaluates 3 selective media (Pylori agar [bioMérieux, France], BD Helicobacter agar, modified [Becton Dickinson, USA], and an in-house medium) designed for Helicobacter pylori isolation. Ninety-eight strains were isolated from 400 gastric biopsies. The media were equally efficient for Helicobacter pylori's growth. However, contaminations were only observed using commercial media.     

Direct detection and analysis of vacA genotypes and cagA gene of Helicobacter pylori from gastric biopsies by a novel multiplex polymerase chain reaction assay

Several tests/methods for the infection, detection, and genotyping of Helicobacter pylori have been developed in the past; all these differ in specificity and sensitivity and thereby could not be routinely used in clinical study especially in resource-poor developing countries. In the present study, a novel method based on multiplex polymerase chain reaction (PCR) assay was developed to detect H. pylori in patients suffering from gastrointestinal diseases. This method does not require steps of sonication, boiling, or centrifugation for obtaining DNA from biopsy samples, which are otherwise prerequisite in detecting H. pylori by PCR assay. Two hundred seventy-six patients were examined, of which 182 cases (excluding 36 patients having multiple H. pylori strain infection and 8 showing amplification of 16S rDNA only) were H. pylori positive. The dominant vacA genotype was s1 and m1 being present in 168 (92.3%) and 106 (58.2%) patients, respectively, followed by m2 (41.7%), and the lowest being s2 (7.7%). Detection of H. pylori by this method seems rapid, simpler, and suitable for both types 1 and 2 bacteria. Furthermore, genotyping of vacA and cagA genes could also be routinely performed in a large number of patients for diagnostic purposes.     

氨茶碱对淋巴瘤细胞系增殖与凋亡的影响及机制探讨

为探讨磷酸二酯酶（phosphodiesterase，PDE）抑制剂在淋巴瘤细胞增殖与凋亡中的作用及机制，研究了非选择性PDE抑制剂氨茶碱（aminophylline，AM）对Burkitt淋巴瘤细胞系Raji的影响。采用MTT检测，光学显微术，电镜术及膜联蛋白V染色观察细胞增殖、细胞凋亡的形态学变化及凋亡率；用流式细胞术和RT-PCR技术检测细胞周期，周期蛋白B1和Bcl-2的表达及线粒体跨膜电位的变化。结果显示，氨茶碱对Raji细胞增殖呈浓度依赖性抑制作用；形态学观察发现随氨茶碱浓度增加，细胞体积明显缩小，核固缩，核染色质核膜下聚集，出现凋亡小体；细胞涂片显示，核染色质凝聚、核碎裂；电镜观察有典型凋亡细胞；膜联蛋白V染色显示氨茶碱诱导Raji细胞凋亡率增加，线粒体跨膜电位（Δφm）呈浓度依赖性下降；流式细胞术及RT-PCR显示氨茶碱下调Bcl-2蛋白及mR-NA的表达；细胞周期分析显示经氨茶碱处理的细胞出现S期阻滞、细胞周期蛋白B1表达下调。结论：氨茶碱可通过S期阻滞抑制细胞增殖、下调Bcl-2的表达及降低线粒体膜电位而诱导Raji细胞凋亡。     

Roles of oxidative stress in stomach disorders

The stomach is a sensitive digestive organ that is susceptible and exposed to exogenous pathogens from the diet. In response to such pathogens, the stomach induces oxidative stress, which might be related to the development of gastric organic disorders such as gastritis, gastric ulcers, and gastric cancer, as well as functional disorders such as functional dyspepsia. In particular, the bacterium Helicobacter pylori plays a major role in eliciting and confronting oxidative stress in the stomach. The present paper summarizes the pathogenesis of oxidative stress in the stomach during the development of various stomach diseases.     

粘着斑激酶活性对气道上皮细胞增殖的影响

目的：研究粘着斑激酶（focal adhesion kinase，FAK）磷酸化对细胞外基质成份诱导的气道上皮细胞增殖和细胞周期演进的影响，探讨粘着斑激酶活化对气道上皮细胞损伤后修复影响的机制。方法：通过纤维连接蛋白（finbronectin，FN）诱导培养的气道上皮细胞，利用四唑盐（MTT）比色实验研究气道上皮细胞增殖情况，采用流式细胞术分析气道上皮细胞细胞周期各期分布，以Western blot和免疫共沉淀检测FAK表达水平及其酪氨酸磷酸化程度；以FAK反义寡核苷酸（ODNs）经脂质体转染细胞，观察其对FAK磷酸化、细胞增殖和细胞在细胞周期各期分布的影响。结果：FN诱导的气道上皮细胞MTT吸光度明显增强，G1期细胞数量明显减少，S期和G2期细胞数量明显增多，同时FAK表达水平及其酪氨酸磷酸化程度显著增高；经脂质体转染了反义FAK寡核苷酸的气道上皮细胞MTT吸光度值显著降低，G1期细胞数明显增多，S期和G2期细胞数显著减少，FAK表达水平及其酪氨酸磷酸化程度降低，且与Gt期细胞数量的增多成显著负相关，与S期、G2期细胞数量和MTT吸光度的减少成明显正相关。结论：FAK是细胞外基质诱导气道上皮细胞增殖的重要信号分子，其活化促进气道上皮细胞的增殖和细胞周期的演进，在气道上皮细胞损伤后修复过程中起重要作用。     

2-甲氧基雌二醇对骨髓瘤细胞系增殖与凋亡的影响

为了探讨2-甲氧基雌二醇对骨髓瘤细胞系增殖及凋亡的影响,并观察其与地塞米松、反应停、三氧化二砷、唑仑膦酸钠等药物联合时的协同作用,采用台盼蓝染色法检测细胞活力,应用BrdU掺入法检测浆细胞标记指数(PCLI),DNA片段原位末端标记(TUNEL法)检测凋亡细胞.药物协同作用判断标准按金氏公式计算Q值.结果表明,7株骨髓瘤细胞系NCI-H929、HS-sultan、KM3、SK0-007、CZ-1、U266、LP-1经1、4、8、12、16 μmol/L 2-甲氧基雌二醇分别作用12、24、36和48小时后细胞活力明显受抑制,呈现时间剂量依赖性,经统计学分析,差异显著(P＜0.05).各细胞系对2-甲氧基雌二醇敏感性不同,其IC50介于(20.8±0.27)μmol/L与(34.1±0.57)μmol/L之间.1、4、8、12、16 μmol/L 2-甲氧基雌二醇分别作用12、24、36和48小时可诱导骨髓瘤细胞系凋亡,凋亡率介于9%-33%之间,呈现时间和剂量依赖性,经统计学分析,差异显著(P＜0.05).经12 μmol/L 2-甲氧基雌二醇作用24小时后浆细胞标记指数(PCLI)由作用前平均(30.14±4.28)%下降到作用后的(14.71±6.27)%,差异显著(P＜0.05).2-甲氧基雌二醇与药物联合作用后计算Q值介于1.13-1.43之间,具有协同作用.结论2-甲氧基雌二醇可抑制骨髓瘤细胞生长,并可诱导骨髓瘤细胞凋亡,与地塞米松、反应停、三氧化二砷、唑仑膦酸钠联合使用具有协同作用.     

黄芪多糖对人胃癌细胞MKN45诱导凋亡和细胞周期的影响

目的 观察不同浓度﹑不同时间的黄芪多糖对人胃癌细胞MKN45的影响.方法 应用四甲基偶氮唑蓝（MTT）实验﹑流式细胞仪﹑细胞免疫组化等方法对人胃癌细胞MKN45进行检测.结果 MTT实验显示黄芪多糖可抑制MKN45细胞增殖;细胞周期分析提示黄芪多糖可将细胞MKN45阻滞于G0/G1期,均与浓度和时间呈正相关;免疫组化法显示凋亡相关基因Bcl-2蛋白表达下调, Bax蛋白表达上调.结论 黄芪多糖对人胃癌细胞MKN45有直接杀伤作用,同时诱导肿瘤细胞凋亡,可将细胞周期阻滞于G0/G1期,其作用机制可能通过上调促凋亡蛋白和下调抑制凋亡蛋白实现.     

黄芪多糖对人胃癌细胞MKN45诱导凋亡和细胞周期的影响

目的观察不同浓度不同时间的黄芪多糖对人胃癌细胞MKN45的影响。方法应用四甲基偶氮唑蓝(MTT)实验流式细胞仪细胞免疫组化等方法对人胃癌细胞MKN45进行检测。结果 MTT实验显示黄芪多糖可抑制MKN45细胞增殖;细胞周期分析提示黄芪多糖可将细胞MKN45阻滞于G0/G1期,均与浓度和时间呈正相关;免疫组化法显示凋亡相关基因Bcl-2蛋白表达下调,Bax蛋白表达上调。结论黄芪多糖对人胃癌细胞MKN45有直接杀伤作用,同时诱导肿瘤细胞凋亡,可将细胞周期阻滞于G0/G1期,其作用机制可能通过上调促凋亡蛋白和下调抑制凋亡蛋白实现。     

Strategies for peptic ulcer healing after 1 week proton pump inhibitor-based triple Helicobacter pylori eradication therapy in Japanese patients: differences of gastric ulcers and duodenal ulcers

Helicobacter pylori (H. pylori) eradication therapy alone is insufficient to ensure healing of large ulcers with H. pylori-positive gastric ulcer (GU). The question of what is the optimum antiulcer treatment following H. pylori eradication therapy has not been fully elucidated. Furthermore, the ulcer healing effects of eradication therapy itself with H. pylori-positive duodenal ulcer (DU) have not been investigated. In GU study, the eradication therapy + proton pump inhibitor (PPI) group (group A) were administered eradication therapy followed by 7 weeks of a PPI, and the eradication therapy + gastroprotective drug (GP) group (group B) eradication therapy followed by 7 weeks of a GP. In DU study, the eradication therapy + PPI group (group C) were administered eradication therapy followed by 5 weeks of a PPI, and the eradication therapy only group (group D) was eradication therapy alone. In GU study, healing rates for ulcer of ≥15 mm in diameter were significant greater in the group A. In DU study, high healing rates were seen both the group C and D. In conclusion, a PPI could significantly heal GU than a GP after eradication therapy in GU. Meanwhile, the eradication alone is sufficient for DU.     

D-柠檬烯对K562细胞增殖及凋亡的影响

本研究探讨D-柠檬烯对K562白血病细胞增殖的影响及机制。应用MTT试验观察不同浓度D-柠檬烯作用后K562细胞增殖的改变；应用细胞形态学检查、流式细胞术、DNA琼脂糖凝胶电泳观察和检测细胞凋亡。结果表明：在0．125-1．0mmol／L浓度范围内，D-柠檬烯对K562细胞增殖的抑制作用呈现剂量依赖的关系。典型的细胞形态学改变、DNA琼脂糖凝胶电泳梯形条带及流式细胞仪检测出亚G1峰共同证实了D-柠檬烯能诱导K562白血病细胞凋亡。结论：D-柠檬烯抑制K562细胞的增殖并呈剂量依赖的方式，使细胞滞留于G1期，诱导其凋亡。     

丙戊酸钠抑制HL-60细胞增殖并诱导其凋亡与分化

为进一步研究丙戊酸钠(sodium valproate;VPA)对白血病细胞HL-60的增殖、凋亡和分化的影响,采用MTT法检测不同浓度的VPA对HL-60细胞增殖的作用;细胞化学染色法观察药物作用后细胞形态的变化;NBT还原实验结合形态学作为观测细胞分化指标;应用流式细胞术检测不同浓度药物作用后细胞周期的变化及凋亡细胞的比例。结果显示:VPA能明显抑制HL-60的增殖;经2mmol/L VPA处理24-48小时后,HL-60出现胞浆空泡、核固缩、核碎裂及凋亡小体;Annexin V阳性的早期凋亡细胞比例由2.9%升高到17.1%;流式细胞术检测出明显的亚二倍体峰;G1期细胞由51.1%增加至84.6%,S期细胞由37.9%减低至14.4%。0.25mmol/L VPA作用1周后,促进HL-60细胞向中幼粒、晚幼粒阶段分化,NBT阳性细胞百分率为(47±2)%。结论:VPA能明显抑制白血病细胞HL-60的增殖,并诱导其分化及凋亡。