Effect of Helicobacter pylori infection on the link between GLP-1 expression and motility of the gastrointestinal tract

Extracellular vesicles from helicobacter pylori-infected cells and helicobacter pylori outer membrane vesicles in atherosclerosis

BACKGROUND

The role of H. pylori infection has been reported in various extragastric diseases, particularly, the correlation between H. pylori and atherosclerosis (AS) have received lots of attention. Some scholars demonstrated that the presence of H. pylori-specific DNA in the sclerotic plaques of atheromatous patients provides biological evidences, with indicating that H. pylori infection is a potential factor of AS. However, the underlying mechanism of H. pylori or their products cross the epithelial barriers to enter the blood circulation remains unclear. Recent studies have shown that the extracellular vesicles (EVs) derived from H. pylori-infected gastric epithelial cells encapsulated H. pylori virulence factor cytotoxin-associated gene A (CagA) and existed in the blood samples of patients or mice, which indicating that they can carry CagA into the blood circulation. Based on these findings, some researchers proposed a hypothesis that H. pylori is involved in the pathogenesis of AS via EVs-based mechanisms. In addition, outer membrane vesicles (OMVs) serve as transport vehicles to deliver H. pylori virulence factors to epithelial cells. It is necessary to discuss the role of H. pylori OMVs in the development of AS.

OBJECTIVES

This review will focus on the correlation between H. pylori infection and AS and tried to unveil the possible role of EVs from H. pylori-infected cells and H. pylori OMVs in the pathogenesis of AS, with a view to providing help in refining our knowledge in this aspect.

METHODS

All of information included in this review was retrieved from published studies on H. pylori infection in AS.

RESULTS

H. pylori infection may be an atherosclerotic risk factor and drives researchers to reevaluate the role of H. pylori in the pathogenesis of AS. Some findings proposed a new hypothesis that H. pylori may be involved in the pathogenesis of AS through EVs-based mechanisms. Besides EVs from H. pylori-infected cells, whether H. pylori OMVs may play some role in the pathogenesis of AS is still remain unclear.

CONCLUSION

Existing epidemiological and clinical evidence had shown that there is a possible association between H. pylori and AS. However, except for the larger randomized controlled trials, more basic research about EVs from H. pylori-infected cells and H. pylori OMVs is the need of the hour to unveil the possible role of H. pylori infection in the pathogenesis of AS.

Investigating Helicobacter pylori-related pyloric hypomotility: functional, histological, and molecular alterations

Multiple theories have been proposed describing the pathogenic mechanisms of Helicobacter pylori (H. pylori)-associated gastric motility disorders. We assessed ex vivo pyloric activity in H. pylori-infected rats, and tried to explore the associated ghrelin hormone alteration and pyloric fibrogenesis. In addition, miR-1 was assessed in pyloric tissue samples, being recently accused of having a role in smooth muscle dysfunction. Ninety adult male Wistar albino rats were assigned into nine groups: 1) control group, 2) sterile broth (vehicle group), 3) amoxicillin control, 4) omeperazole control, 5) clarithromycin control, 6) triple therapy control, 7) H. pylori- group, 8) H. pylori-clarithromycin group, and 9) H. pylori-triple therapy group. Urease enzyme activity was applied as an indicator of H. pylori infection. Ex vivo pyloric contractility was evaluated. Serum ghrelin was assessed, and histological tissue evaluation was performed. Besides, pyloric muscle miR-1 expression was measured. The immunological epithelial to mesenchymal transition (EMT) markers; transforming growth factor β (TGFβ), α-smooth muscle actin (α-SMA), and E-cadherin-3 were also evaluated. By H. pylori infection, a significant (P < 0.001) reduced pyloric contractility index was recorded. The miR-1 expression was decreased (P < 0.001) in the H. pylori-infected group, associated with reduced serum ghrelin, elevated TGFβ, and α-SMA levels and reduced E-cadherin levels. Decreased miR-1 and disturbed molecular pattern were improved by treatment. In conclusion, H. pylori infection was associated with reduced miR-1, epithelial to mesenchymal transition, and pyloric hypomotility. The miR-1 may be a target for further studies to assess its possible involvement in H. pylori-associated pyloric dysfunction, which might help in the management of human H. pylori manifestations and complications.NEW & NOTEWORTHY This work is investigating functional, histopathological, and molecular changes underlying Helicobacter pylori hypomotility and is correlating these with miR-1, whose disturbance is supposed to be involved in smooth muscle dysfunction and cell proliferation according to literature. Epithelial to mesenchymal transition and reduced ghrelin hormone may contribute to H. pylori infection-associated hypomotility. H. pylori infection was associated with reduced pyloric miR-1 expression. Targeting miR-1 could be valuable in the clinical management of pyloric hypofunction.

Observation of tumor-associated macrophages expression in gastric cancer and its clinical pathological relationship

The present study was designed to investigate the expression of tumor-associated macrophages (TAMs) in gastric cancer and its clinicopathological relationship. In addition, we also aimed to analyze the relationship between helicobacter pylori (HP) infection and TAMs in gastric cancer.The protein expression of CD16 and CD163 in 90 gastric cancer tissues and 30 margin tissues was detected by immunohistochemistry. HP infection was detected in 90 gastric cancer tissues and 30 margin tissues by gram staining and immunohistochemistry.There was no clear correlation between CD16 macrophages and gastric cancer. The density of CD163 macrophages was not correlated with the general condition of tumor patients, but with tumor size, tumor differentiation, lymphatic metastasis, depth of invasion and TNM stage. Additionally, the infection rate of HP in gastric cancer tissues was significantly higher.In summary, TAMs are associated with tumor size, degree of differentiation, depth of invasion, lymph node metastasis and TNM stage, suggesting their critical role in the invasion and metastasis of gastric cancer.

Helicobacter pylori eradication in dyspepsia: New evidence for symptomatic benefit

A causal relationship between Helicobacter pylori (H. pylori) infection and functional dyspepsia (FD) is well established in a subset of infected patients. In the Kyoto and Maastricht/Florence consensus reports H. pylori-associated dyspepsia is defined as an independent entity distinct from FD. H. pylori eradication is therefore the most cost-effective approach for infected patients with dyspeptic symptoms and superior to other medical therapies, such as Proton Pump Inhibitors. The therapeutic gain of H.pylori eradication for symptom relief compared to other therapeutic options is significant with the number needed to benefit of 12. Furthermore H.pylori cures chronic gastritis except in severe cases of atrophic gastritis and may prevent severe complications attributable to the infection. Several pathophysiological mechanisms are suggested for the generation of symptoms and are related to the distinct topographic expression and degree of gastric inflammation as well as changes of gastric acid secretion, gastrointestinal motility and visceral hypersensitivity.

Alteration of GLP-1/GPR43 expression and gastrointestinal motility in dysbiotic mice treated with vancomycin

Gut microbiota plays a pivotal role in various aspects of host physiology, including metabolism, gastrointestinal (GI) motility and hormonal secretion. In the present study, we investigated the effect of antibiotic-associated dysbiosis on metabolism and GI motility in relation to colonic expression of glucagon-like peptide-1 (GLP-1) and G protein coupled receptor (GPR)43. Specific pathogen-free (SPF) mice (ICR, 6 weeks old, female) were orally administered vancomycin (0.2 mg/ml) in drinking water for 7 days. In another experiment, germ-free (GF) mice (ICR, 6 weeks old, female) were subjected to oral fecal transplantation (FT) using a fecal bacterial suspension prepared from SPF mice that had received vancomycin treatment (FT-V) or one from untreated control SPF mice (FT-C). The gastrointestinal transit time (GITT) was measured by administration of carmine red (6% w/v) solution. The expression of GLP-1 and GPR43 was examined by immunohistochemistry and realtime RT-PCR, and the plasma GLP-1 level was measured by ELISA. In vancomycin-treated SPF mice, the diversity of the gut microbiota was significantly reduced and the abundance of Lactobacillus was markedly increased. Significant increases in body weight, cecum weight, plasma GLP-1 level and colonic GLP-1/GPR43 expression were also noted relative to the controls. These alterations were reproducible in GF mice with FT-V. Moreover, FT-V GF mice showed a significantly increased food intake and a significantly prolonged GITT in comparison with FT-C GF mice. Vancomycin-induced dysbiosis promotes body weight gain and prolongs GITT, accompanied by an increase of colonic GLP-1/GPR43 expression.

Structure Dependent-Immunomodulation by Sugar Beet Arabinans via a SYK Tyrosine Kinase-Dependent Signaling Pathway

There is much interest in the immunomodulatory properties of dietary fibers but their activity may be influenced by contamination with microbial-associated molecular patterns (MAMPs) such as lipopolysaccharide (LPS) and lipoteichoic acids, which are difficult to remove completely from biological samples. Bone marrow-derived dendritic cells (BMDCs) from TLR2x4 double-KO mice were shown to be a reliable approach to analyse the immunomodulatory properties of a diverse range of dietary fibers, by avoiding immune cell activation due to contaminating MAMPs. Several of the 44 tested dietary fiber preparations induced cytokine responses in BMDCs from TLR2x4 double-KO mice. The particulate fractions of linear arabinan (LA) and branched arabinan (BA) from sugar beet pectin were shown to be strongly immune stimulatory with LA being more immune stimulatory than BA. Enzymatic debranching of BA increased its immune stimulatory activity, possibly due to increased particle formation by the alignment of debranched linear arabinan. Mechanistic studies showed that the immunostimulatory activity of LA and BA was independent of the Dectin-1 recognition but Syk kinase-dependent.

Association between gastrointestinal motility and macrophage/mast cell distribution in mice during the healing stage after DSS‑induced colitis

Irritable bowel syndrome (IBS) frequently occurs after infectious colitis or inflammatory bowel disease in patients with complete remission. This suggests that post‑inflammation‑associated factors may serve a role in the pathophysiology of IBS; however, the mechanism responsible remains unclear. In the present study, the involvement of macrophages and mast cells in alteration of gastrointestinal (GI) motility was investigated in mice in the remission stage after acute colitis. C57BL/6 mice were administered 2% dextran sulfate sodium in drinking water for 5 days and their intestinal tissues were investigated at intervals for up to 24 weeks. Expression of the mannose receptor (MR) and tryptase was examined by immunohistochemistry, and the GI transit time (GITT) was measured by administration of carmine red solution. A minimal degree of inflammatory cell infiltration persisted in the colon and also the small intestine of mice in remission after colitis and the GITT was significantly shorter. The number of muscularis MR‑positive macrophages was significantly increased in the small intestine of mice in remission after colitis and negatively correlated with GITT. Furthermore, results indicated that the number of muscularis tryptase‑positive mast cells was significantly increased throughout the intestine of mice during the healing process after colitis and was positively correlated with GITT. The present findings suggested an increased number of macrophages and/or mast cells in the intestinal muscular layer may be associated with the pathophysiology of GI dysmotility after colitis.

Definition, Pathogenesis, and Management of That Cursed Dyspepsia

Dyspepsia is an umbrella term used to encompass a number of symptoms thought to originate from the upper gastrointestinal tract. These symptoms are relatively nonspecific; not surprisingly, therefore, a myriad of conditions may present with any one or a combination of these symptoms. Therein lays the clinician's first challenge: detecting the minority who may have a potentially life-threatening disorder, such as gastric cancer, from a population whose symptoms are, for the most part, considered functional in origin. The second challenge lies in the definition and management of those individuals with functional dyspepsia (FD); the major focus of this review. The Rome process has addressed the issue of FD definition and a look back at the evolution of Rome criteria for this disorder illustrates the complexities that have so frustrated us. There has been no shortage of hypotheses to explain symptom pathogenesis in FD; initially focused on gastric sensorimotor dysfunction, these have now strayed well into the duodenum and have come to entertain such factors as immune responses and the microbiome. FD has proven to be an equally challenging area for therapeutics; while the staple approaches of acid suppression and eradication of Helicobacter pylori have some limited efficacy in select populations, strategies to ameliorate symptoms in the majority of sufferers based on presumed pathophysiology have largely foundered. Lacking a validated biomarker(s) FD continues to be an elusive target and is likely to remain so until we can better define the various phenotypes that it must surely contain.