Acid, helicobacter and immunity: a new paradigm for oesophagogastric cancer.

Epidemiological evidence has clearly shown a highly significant relationship between Helicobacter pylori infection and the development of duodenal ulcer and distal gastric adenocarcinoma. Despite H. pylori being a common aetiological factor for both disorders, the two disease phenotypes are virtually mutually exclusive. This indicates that the host response to infection has a pivotal role in determining outcome; these disease phenotypes relate to the effect of infection on gastric acid secretion, duodenal ulcer being closely related to sustained acid secretion whereas gastric cancer follows gastric atrophy and impaired gastric acid secretion. Cancer at the oesophageal junction and that associated with Barrett's oesophagus is now the most rapidly increasing tumour in the gastrointestinal tract. The challenge for the next millennium, therefore, is to try and develop methods for identifying patients at risk of developing oesophagogastric cancer. A common feature in the pathogenesis of both gastric and oesophageal adenocarcinoma is inflammation presenting clinically as gastritis and oesophagitis. The pathway from gastritis to gastric atrophy, dysplasia and carcinoma is thought to be a multi-step process, probably triggered by free radicals within the gastric epithelium and increased exposure to luminal carcinogens. However, it has been unclear as to which aspect of the host response determines whether an individual will move along the neoplasia pathway. Recent work has shown that qualitative aspects of the immune environment in the stomach may account for a substantial part of the phenotypic divergence following H. pylori infection. Interleukin-1 beta polymorphisms relate closely to the propensity for an individual to develop distal gastric cancer and maybe useful for predicting risk in family members. In Barrett's oesophagus, we have recently shown that the immune environment may also be important in determining whether an individual will develop cancer. Although we did not find that Barrett's oesophagus was a profoundly inflammatory condition (unlike esophagitis in the squamous epithelium), where there was evidence of inflammation it was qualitatively different from that of oesophagitis in that a Th-2 response with increased expression of IL-4 predominated in Barrett's, whereas a Th-1 proinflammatory response characterised oesophagitis in squamous epithelium. It seems likely that the specific immune environment within Barrett's metaplasia may be an important driver towards dysplasia and carcinoma. Thus, the immune environment in the stomach and esophagus may be critical in determining whether an individual is at risk of developing neoplastic complications of H. pylori infection and gastroesophageal reflux. Identification of the genetic factors which underpin these responses may ultimately result in development of methods to identify individuals at high risk.     

Helicobacter pylori, ethnicity, and the gastroesophageal reflux disease spectrum: a study from the East

BACKGROUND: Ethnic differences in gastroesophageal reflux disease (GERD) and its complications as well as racial variations in the prevalence of Helicobacter pylori infection are well documented. Nevertheless, the association between reflux disease, H. pylori, and race has not been adequately explored. AIMS: We estimated the strength of the association between H. pylori, ethnicity, and the gastroesophageal reflux disease (GERD) spectrum, including Barrett's esophagus, in Asian patients presenting for endoscopy in a tertiary referral center. METHODS: Prospectively, we studied 188 consecutive patients with GERD, short- and long-segment Barrett's esophagus, and controls. All patients underwent gastroscopy with gastric biopsies to assess H. pylori, gastritis, and atrophy. CagA status and H. pylori infection were determined by immunoblot assay. RESULTS: The overall prevalence of H. pylori infection was 52.1% (of which 77.6% were cagA(+)) and was lowest in the long-segment Barrett's esophagus group (36.7%) (p = .048). When Barrett's esophagus was present, the length of abnormality was 44.8% shorter in the presence of H. pylori (p = .015). Indians had the highest prevalence of H. pylori (75%) and Malays the lowest (19.6%) (p < .001). In Indians, increased prevalence of H. pylori and cagA-positive strains was associated with reduced severity of GERD (p < .004 and p < .001, respectively), a trend not apparent in the other races. Corpus atrophy, which was almost exclusively associated with H. pylori, was highest in Indians as compared to the other races (p = .013). CONCLUSIONS: Presence of H. pylori was associated with a reduced severity of GERD spectrum disease in Asians, especially Indians. H. pylori infection may protect against complicated reflux disease via induction of corpus atrophy.     

Helicobacter pylori and Non-malignant Diseases

In 2007 Helicobacter pylori research continued to deal with some controversies raised in the last decade. The main problems remain unsolved: peptic ulcer disease negative for H. pylori , synergism of H. pylori infection and aspirin and other nonsteroidal anti-inflammatory drugs or cyclooxygenase 2 specific inhibitors, the role of H. pylori eradication in uninvestigated and nonulcer dyspepsia, and the possible protective effect of H. pylori infection against gastroesophageal reflux disease and its complications such as Barrett's esophagus and adenocarcinoma. The incidence and prevalence of peptic ulcer disease as well as ulcer-related mortality are continuing to decline all over the world. The increasing consumption of anti-inflammatory and antisecretory drugs was not found to change the trend over the last period and therefore H. pylori was considered the key factor in causing ulcer-related mortality. Some progress has been achieved in understanding H. pylori -induced immunological processes, and attack mechanisms, as well as specific pathogenesis in uremic and cirrhotic patients. There is still a lot to learn about the bacterium and host factors related to H. pylori infection and its complications.     

Acid, bile, and CDX: the ABCs of making Barrett's metaplasia

Barrett's esophagus, a squamous-to-columnar cell metaplasia that develops as a result of chronic gastroesophageal reflux disease (GERD), is a risk factor for esophageal adenocarcinoma. The molecular events underlying the pathogenesis of Barrett's metaplasia are poorly understood, but recent studies suggest that interactions among developmental signaling pathways, morphogenetic factors, and Caudal homeobox (Cdx) genes play key roles. Strong expression of Cdx genes normally is found in the intestine but not in the esophagus and stomach. When mice are genetically engineered so that their gastric cells express Cdx, the stomach develops a metaplastic, intestinal-type epithelium similar to that of Barrett's esophagus. Exposure to acid and bile has been shown to activate the Cdx promoter in certain esophageal cell lines, and Cdx expression has been found in inflamed esophageal squamous epithelium and in the specialized intestinal metaplasia of Barrett's esophagus. Barrett's metaplasia must be sustained by stem cells, which might be identified by putative, intestinal stem cell markers like leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) and doublecortin and CaM kinase-like-1 (DCAMKL-1). Emerging concepts in tumor biology suggest that Barrett's cancers may develop from growth-promoting mutations in metaplastic stem cells or their progenitor cell progeny. This report reviews the roles of developmental signaling pathways and the Cdx genes in the development of normal gut epithelia and the potential mechanisms whereby GERD may induce the esophageal expression of Cdx genes and other morphogenetic factors that mediate the development of Barrett's metaplasia. The role of stem cells in the development of metaplasia and in carcinogenesis and the potential for therapies directed at those stem cells also is addressed.     

Does Helicobacter pylori infection contribute to gastroesophageal reflux disease?

Helicobacter pylori organisms that infect the stomach conceivably could contribute to esophageal inflammation in patients with gastroesophageal reflux disease (GERD) through any of at least three potential mechanisms: 1) by causing an increase in gastric acid secretion; 2) by spreading to infect the gastric-type columnar epithelium that occasionally can line the distal esophagus; and/or 3) by secreting noxious bacterial products into the gastric juice. Studies regarding these potential mechanisms are discussed in this report. Most investigations have found no apparent association between H. pylori infection and reflux esophagitis. Presently, infection with H. pylori does not appear to play an important role in the pathogenesis of GERD.     

Protective effects of Helicobacter pylori against gastroesophageal reflux disease may be due to a neuroimmunological anti-inflammatory mechanism

There is some evidence that Helicobacter pylori infection has a protective effect against gastroesophageal reflux disease (GORD) and its complications such as Barrett's oesophagus and oesophageal adenocarcinoma. In this paper, we propose that a neuroimmunological mechanism is responsible for the protective effect of H. pylori on GORD. H. pylori infection of the gastric mucosa induces a T helper1-like immune response and production of pro-inflammatory cytokines. These cytokines can inhibit local sympathetic tone, whereas they increase systemic sympathetic tone. Increased sympathetic tone can induce an anti-inflammatory milieu, which in turn can inhibit inflammation in the oesophagus and lower oesophageal sphincter (LOS). Furthermore, H. pylori infection may stimulate the cholinergic anti-inflammatory pathway. It has been suggested that reflux-induced oesophageal inflammation plays an important role in the pathogenesis of reflux oesophagitis. Reduction of oesophageal inflammation by increased systemic sympathetic tone and vagal activity may lead to a decrease in reflux-induced oesophageal injury and LOS dysfunction in GORD.     

Changing pattern of cytokeratin 7 and 20 expression from normal epithelium to intestinal metaplasia of the gastric mucosa and gastroesophageal junction

It is currently unclear whether intestinal metaplasia at the esophagogastric junction and in the distal esophagus represent a continuum of the same underlying disease process, i.e., gastroesophageal reflux, or constitute different entities with a different pathogenesis. Biopsies below the Z line might show specialized epithelium in some patients and the question is whether this is another form of short segment Barrett's esophagus or whether it is related to a generalized atrophic process of the stomach. Data from recent studies regarding the expression of cytokeratin CK7 and CK20 in intestinal metaplasia (IM) found at the gastroesophageal junction are conflicting. Prompted by these data we undertook the present study: a) to evaluate the expression of CK7 and CK20 in IM of the gastric cardia and to compare the findings with those in patients with Barrett's esophagus and IM of the gastric corpus and antrum mucosa; and b) to evaluate the immunophenotype of non-intestinalized cardiac mucosa and to compare it with that of normal gastric epithelium. We studied the expression of CK7 and CK20 on biopsy specimens from patients with long-segment Barrett's esophagus (n=17) and surgical resection and biopsy specimens of gastric cardia (n=15), corpus (n=14) and antrum (n=22) from patients with histological evidence of IM. Eighty-four biopsy specimens from 42 patients (antrum n=15, corpus n=20, cardia n=7) without evidence of IM were studied as a control group. We observed an immunophenotype characterised by diffuse moderate to strong CK7 staining on the surface and crypt epithelium combined with strong CK20 staining on the surface and superficial part of the crypts in 94.1% (16/17) of the cases with long-segment Barrett's esophagus, but in none of the 36 cases with IM in distal stomach (antrum and corpus). IM in the gastric cardia expressed the immunophenotype seen in IM of the gastric mucosa in 93.3% (14/15) of the cases. On the other hand, normal cardiac epithelium expressed patchy strong CK7 staining on the surface epithelium and on both, superficial and deep parts of the pits combined with patchy strong CK20 staining on the surface epithelium and superficial pits, a feature permitting distinction of the normal cardiac epithelium from those of the normal gastric antrum and corpus epithelium. We conclude that the expression of cytokeratins 7 and 20 can be used to distinguish the origin of IM of the gastroesophageal junction. The CK7/20 immunophenotype of IM in the gastric cardia closely resembles that of the IM in the gastric antrum and corpus and is different from IM in long-segment Barrett's esophagus. In contrast, the CK7/20 immunophenotype of the cardiac epithelium is different from that of the gastric antrum and corpus mucosa, suggesting that cardiac epithelium might not be a native normal gastric epithelium but one that is acquired as a consequence of longstanding inflammation. Changing pattern of CK7 and CK20 expression from normal to intestinalized epithelium suggests that IM arising from cardiac epithelium might have distinctive features.     

Cloning and expression of Helicobacter pylori GDP-l-fucose synthesizing enzymes (GMD and GMER) in Saccharomyces cerevisiae.

Helicobacter pylori is a Gram-negative gastric pathogen causing diseases from mild gastric infections to gastric cancer. The difference in clinical outcome has been suggested to be due to strain differences. H. pylori undergoes phase variation by changing its lipopolysaccharide structure according to the environmental conditions. The O-antigen of H. pylori contains fucosylated glycans, similar to Lewis structures found in human gastric epithelium. These Lewis glycans of H. pylori have been suggested to play a role in pathogenesis in the adhesion of the bacterium to gastric epithelium. In the synthesis of fucosylated structures, GDP-l-fucose is needed as a fucose donor. Here, we cloned the two key enzymes of GDP-l-fucose synthesis, H. pylori gmd coding for GDP-d-mannose dehydratase (GMD), and gmer coding for GDP-4-keto-6-deoxy-d-mannose-3,5-epimerase/4-reductase (GMER) and expressed them in an enzymatically active form in Saccharomyces cerevisiae. The end product of these enzymes, GDP-l-fucose was used as a fucose donor in a fucosyltransferase assay converting sialyl-N-acetyllactosamine to sialyl Lewis X.     

p53 and the malignant progression of Barrett's esophagus

Barrett's esophagus (BE) is a metaplastic disorder in which specialized columnar epithelium replaces healthy squamous epithelium (intestinal metaplasia). Even though its pathophysiology and the steps of its neoplastic progression are not completely understood, BE can be considered as a complication of gastroesophageal reflux disease (GERD). Given that esophageal adenocarcinoma, which is continually increasing in the Western world, still has a poor prognosis and suffers from late diagnosis, and because BE is a precancerous lesion, there is a strong need for good molecular markers of malignant progression in Barrett's metaplasia (BM). The aim of this review is to examine the published data regarding the role that assessment of p53 may play in the management of BE, trying to understand if it may be a useful marker to early diagnose BE malignant transformation.     

Failure of capsaicin-containing red pepper sauce suspension to induce esophageal motility response in patients with Barrett's esophagus.

The physiologic importance of afferent sensory pathways in the esophageal motor functions has been recently recognised. Capsaicin-sensitive sensory afferents were shown to play a role in the maintenance of mucosal integrity of the GI tract, and regulation of human esophageal motility. The aim of this study was to investigate the effect of topical application of capsaicin-containing red pepper sauce (Tabasco, 25%v/v, pH:7.0) suspension on the phasic activity of the human esophagus of healthy volunteers and patients with Barrett's esophagus. METHODS: The diagnosis of Barrett's esophagus was based on the findings of esophagoscopy and histology taken from the squamocolumnar junction of the esophagus. Esophageal motility was measured by perfusion manometry before and after application of red pepper sauce. RESULTS: Capsaicin containing red pepper sauce increases the motility response (LES tone, contraction amplitude, propagation velocity) of the human esophagus in healthy volunteers. This response failed in patients with Barrett's esophagus. CONCLUSION: Impaired esophageal sensory motor function may serve as one etiologic role in the development of Barrett's esophagus.     

Specificity of histological interrelations of cardial glands of the esophagus with its multi-layer lining]

Bioptates obtained from 163 mature persons have been studied, using spiral sections. When the conditions of functioning are altered (at the gastro-esophageal reflux) the organ's integument can destroy, but the defects formed in the lining are covered with a simple cylinder epithelium of the cardial glands. A connection between Barrett's syndrome in the esophagus with its cardial gland is demonstrated. The most widely distributed histological forms of Barrett's esophagus are described.     

Deoxycholic acid impairs glycosylation and fucosylation processes in esophageal epithelial cells

It is generally accepted that esophageal adenocarcinoma arises from a Barrett's metaplastic lesion. Altered glycoprotein expression has been demonstrated in tissue from patients with Barrett's esophagus and esophageal cancer but the mechanisms regarding such changes are unknown. The bile acid deoxycholic acid (DCA) alters many cell signaling pathways and is implicated in esophageal cancer progression. We have demonstrated that DCA disrupts Golgi structure and affects protein secretion and glycosylation processes in cell lines derived from normal squamous epithelium (HET-1A) and Barrett's metaplastic epithelium (QH). Cell surface expression of glycans was identified using carbohydrate-specific probes (wheat germ agglutinate, conconavalin A, peanut agglutinin, lithocholic acid and Ulex europaeus agglutinin) that monitored N-glycosylation, O-glycosylation and core fucosylation in resting and DCA-treated cells. DCA altered intracellular localization and reduced cell surface expression of N-acetyl-D-glucosamine, α-methyl-mannopyranoside (Man/Glc) and fucose in both cell lines. Furthermore, DCA reduced the expression of epithelial growth factor receptor and E-cadherin in a manner analogous to treatment of cells with the N-glycan biosynthesis inhibitor tunicamycin. This is the first study to identify an altered Golgi structure and glycomic profile in response to DCA in esophageal epithelial cells, a process which could potentially contribute to metaplasia, dysplasia and cancer of the esophagus.     

GERD is associated with shortened telomeres in the squamous epithelium of the distal esophagus

Telomeres are repetitive DNA sequences located at the ends of chromosomes. Telomeres are shortened by repeated cell divisions and by oxidative DNA damage, and cells with critically shortened telomeres cannot divide. We hypothesized that chronic gastroesophageal reflux disease (GERD)-induced injury of the esophageal squamous epithelium results in progressive telomeric shortening that eventually might interfere with mucosal healing. To address our hypothesis, we compared telomere length and telomerase activity in biopsy specimens of esophageal squamous epithelium from GERD patients and control patients. Endoscopic biopsies were taken from the esophageal squamous epithelium of 38 patients with GERD [10 long-segment Barrett's esophagus (LSBE), 15 short-segment (SSBE), 13 GERD without Barrett's esophagus] and 16 control patients without GERD. Telomere length was assessed using the terminal restriction fragment assay, and telomerase activity was studied by the PCR-based telomeric repeat amplification protocol assay. Patients with GERD had significantly shorter telomeres in the distal esophagus than controls [8.3 +/- 0.5 vs. 10.9 +/- 1.5 (SE) Kbp, P = 0.043]. Among the patients with GERD, telomere length in the distal esophagus did not differ significantly in those with and without Barrett's esophagus (LSBE 7.9 +/- 0.8, SSBE 8.6 +/- 0.9, GERD without BE 8.7 +/- 1.0 Kbp). No significant differences in telomerase activity in the distal esophagus were noted between patients with GERD and controls (4.0 +/- 0.39 vs. 5.2 +/- 0.53 RIUs). Telomeres in the squamous epithelium of the distal esophagus of patients who have GERD, with and without Barrett's esophagus, are significantly shorter than those of patients without GERD despite similar levels of telomerase activity.     

Gain of allelic gene expression for IGF-II occurs frequently in Barrett's esophagus

The IGF-II gene normally exhibits genomic imprinting, a DNA modification that allows the expression of only one of the two inherited alleles. With loss of imprinting, there is a gain of allelic gene expression (GOAGE) due to IGF-II being expressed by both alleles. GOAGE for IGF-II has been demonstrated in a number of malignancies and in normal epithelia surrounding malignancies, but not in epithelia without associated neoplasia. We hypothesized that nonneoplastic Barrett's epithelium might have GOAGE for IGF-II that could facilitate its progression to neoplasia. Endoscopic biopsies were obtained from metaplastic esophageal, normal gastric, and normal duodenal epithelia from 43 patients with Barrett's esophagus. Genomic DNA were analyzed using PCR followed by ApaI restriction enzyme digestion or allele-specific PCR to identify an ApaI polymorphism of IGF-II. cDNA from patients with the ApaI polymorphism were analyzed for IGF-II GOAGE using exon connection PCR, followed by a secondary nested PCR and ApaI restriction enzyme digestion. We found that 13 (30%) of 43 samples of Barrett's metaplasia contained the ApaI polymorphism and were thus informative for IGF-II, and sufficient material was available for GOAGE analysis in 9 of those 13 cases. GOAGE for IGF-II was demonstrated in five (56%) of those nine cases. All patients with GOAGE in Barrett's metaplasia also demonstrated GOAGE in the gastric and duodenal epithelia. In contrast, patients without GOAGE in Barrett's metaplasia also had no GOAGE in their gastric and duodenal epithelia. We conclude that in patients with Barrett's esophagus, GOAGE for IGF-II is found frequently in the metaplastic esophageal epithelium as well as in normal gastric and duodenal epithelia.     

Helicobacter pylori immunoproteomes in case reports of rosacea and chronic urticaria

Rosacea and chronic urticaria are two common skin disorders existing in idiopathic forms. A role of Helicobacter pylori bacterium infection in the aetiopathogenesis of rosacea or chronic urticaria has been suggested although still controversial. The aim of the present study was to establish a relationship between H. pylori infection and rosacea chronic urticaria by means of an immunoproteomic investigation. We analyzed immunoglobulin A (IgA)-, IgG-, and IgE-mediated immune-responses against H. pylori antigens and we identified some bacterial immunoresponsive proteins. A general IgA- and IgE-mediated immune response against antioxidative bacterial proteins was observed. A correlation between the bacterial occurrence and skin diseases pathogenesis is discussed.     

Use of an improved zirconyl hematoxylin stain in the diagnosis of Barrett's esophagus

Barrett's esophagus is a precancerous condition characterized by replacement of the normal stratified squamous epithelium by a simple columnar epithelium with goblet cells that secrete an acidic mucin. As originally formulated, fresh solutions of zirconyl hematoxylin stain goblet cells poorly. An improved formula, quintupling the amount of oxidant, yields zirconyl hematoxylin solutions that stain goblet cells darkly even when fresh. The improved zirconyl hematoxylin can be used in place of alcian blue in the diagnosis of Barrett's esophagus. The ingredients of zirconyl hematoxylin are always readily available and are generally recognized as safe.     

Helicobacter pylori CagA-dependent macrophage migration inhibitory factor produced by gastric epithelial cells binds to CD74 and stimulates procarcinogenic events

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that has recently been implicated in carcinogenesis. Helicobacter pylori, which is closely linked to gastric cancer, induces the gastric epithelium to produce proinflammatory cytokines, including MIF. MIF can bind to CD74, which we have previously shown to be highly expressed on the surface of gastric epithelial cells (GEC) during H. pylori infection. In this study, we sought to investigate the role of the H. pylori-induced MIF on epithelial proliferation and procarcinogenic events. Upon establishing a role for the H. pylori CagA virulence factor in MIF production, MIF binding to CD74 on GEC was confirmed. rMIF and H. pylori were shown to increase GEC proliferation, which was decreased when cagA- strains were used and when CD74 was blocked by mAbs. Apoptosis was also decreased by MIF, but increased by cagA- strains that induced much lower amounts of MIF than the wild-type bacteria. Furthermore, MIF binding to CD74 was also shown to decrease p53 phosphorylation and up-regulate Bcl-2 expression. This data describes a novel system in which an H. pylori virulence factor contributes to the production of a host factor that in turn up-regulates procarcinogenic events by the gastric epithelium.     

Detection of Helicobacter pylori in saliva and esophagus

The route of Helicobacter pylori transmission remains unclear and the currently suggested route is person-to-person transfer by faecal-oral and oral-oral mode. The aim of this study was to verify the presence of H. pylori in esophagus and saliva of humans. Saliva samples, mucosal biopsies from esophagus, gastric antrum and fundus were collected from 19 patients with positive Urea Breath Test (UBT). Gastric biopsies were used for H. pylori colture and antimicrobial susceptibility tests whereas saliva samples were collected to detect H. pylori with a Nested-PCR targeting 16S rRNA gene as well as esophagus biopsies which were also investigated with immunohistochemical staining. Helicobacter pylori was isolated in 18 patients both in gastric antrum and fundus. The molecular analysis, confirmed by comparative sequences evaluation, gave positive results in all saliva and esophageal samples whereas the immunohistochemistry revealed the presence of H. pylori in 15.8% (3/19) of the esophagus samples. Our data suggest that saliva and esophagus may be considered reservoirs for H. pylori in humans and emphasize the need to use more susceptible techniques for H. pylori detection, in particular in over-crowded sites. Identification of the transmission route of H. pylori is crucial in developing an effective plan of surveillance by finding new means of disease management.