Analysis of the relationship between invasive capability of Helicobacter pylori and gastroduodenal diseases

The role of CEACAMs versus integrins in Helicobacter pylori CagA translocation: a systematic review

The delivery of Helicobacter pylori CagA into host cells was long believed to occur through the integrin cell surface receptors. However, the role of CEACAM receptors has recently been highlighted, instead. Here, we have categorized the existing experimental evidence according to whether deletion, upregulation, downregulation, or inhibition of the target ligands (T4SS or HopQ) or receptors (integrins or CEACAMs), result in alterations in CagA phosphorylation, cell elongation, or IL-8 production. According to our analysis, the statistics favor the essence of most of the T4SS constituents and the involvement of HopQ adhesin in all three functions. Concerning the integrin family, the collected data is controversial, but yielding towards it being dispensable or involved in CagA translocation. Yet, regarding cell elongation, more events are showing β1 integrin being involved, than αvβ4 being inhibitory. Concerning IL-8 secretion, again there are more events showing α5, β1 and β6 integrins to be involved, than those showing inhibitory roles for β1, β4 and β6 integrins. Finally, CEACAM 1, 3, and 5 are identified as mostly essential or involved in CagA phosphorylation, whereasCEACAM 4, 7, and 8 are found dispensable and CEACAM6 is under debate. Conversely, CEACAM1, 5 and 6 appear mostly dispensable for cell elongation. Noteworthy is the choice of cell type, bacterial strain, multiplicity and duration of infection, as well as the sensitivity of the detection methods, all of which can affect the variably obtained results.

Enhanced enzymatic production of cholesteryl 6'-acylglucoside impairs lysosomal degradation for the intracellular survival of Helicobacter pylori

Background

During autophagy defense against invading microbes, certain lipid types are indispensable for generating specialized membrane-bound organelles. The lipid composition of autophagosomes remains obscure, as does the issue of how specific lipids and lipid-associated enzymes participate in autophagosome formation and maturation. Helicobacter pylori is auxotrophic for cholesterol and converts cholesterol to cholesteryl glucoside derivatives, including cholesteryl 6ʹ-O-acyl-α-d-glucoside (CAG). We investigated how CAG and its biosynthetic acyltransferase assist H. pylori to escape host-cell autophagy.

Methods

We applied a metabolite-tagging method to obtain fluorophore-containing cholesteryl glucosides that were utilized to understand their intracellular locations. H. pylori 26695 and a cholesteryl glucosyltransferase (CGT)-deletion mutant (ΔCGT) were used as the standard strain and the negative control that contains no cholesterol-derived metabolites, respectively. Bacterial internalization and several autophagy-related assays were conducted to unravel the possible mechanism that H. pylori develops to hijack the host-cell autophagy response. Subcellular fractions of H. pylori-infected AGS cells were obtained and measured for the acyltransferase activity.

Results

The imaging studies of fluorophore-labeled cholesteryl glucosides pinpointed their intracellular localization in AGS cells. The result indicated that CAG enhances the internalization of H. pylori in AGS cells. Particularly, CAG, instead of CG and CPG, is able to augment the autophagy response induced by H. pylori. How CAG participates in the autophagy process is multifaceted. CAG was found to intervene in the degradation of autophagosomes and reduce lysosomal biogenesis, supporting the idea that intracellular H. pylori is harbored by autophago-lysosomes in favor of the bacterial survival. Furthermore, we performed the enzyme activity assay of subcellular fractions of H. pylori-infected AGS cells. The analysis showed that the acyltransferase is mainly distributed in autophago-lysosomal compartments.

Conclusions

Our results support the idea that the acyltransferase is mainly distributed in the subcellular compartment consisting of autophagosomes, late endosomes, and lysosomes, in which the acidic environment is beneficial for the maximal acyltransferase activity. The resulting elevated level of CAG can facilitate bacterial internalization, interfere with the autophagy flux, and causes reduced lysosomal biogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-021-00768-w.

Helicobacter pylori in gastric cancer: Features of infection and their correlations with long-term results of treatment

BACKGROUND

Helicobacter pylori (H. pylori) is a spiral-shaped bacterium responsible for the development of chronic gastritis, gastric ulcer, gastric cancer (GC), and MALT-lymphoma of the stomach. H. pylori can be present in the gastric mucosa (GM) in both spiral and coccoid forms. However, it is not known whether the severity of GM contamination by various vegetative forms of H. pylori is associated with clinical and morphological characteristics and long-term results of GC treatment.

AIM

To establish the features of H. pylori infection in patients with GC and their correlations with clinical and morphological characteristics of diseases and long-term results of treatment.

METHODS

Of 109 patients with GC were included in a prospective cohort study. H. pylori in the GM and tumor was determined by rapid urease test and by immunohistochemically using the antibody to H. pylori. The results obtained were compared with the clinical and morphological characteristics and prognosis of GC. Statistical analysis was performed using the Statistica 10.0 software.

RESULTS

H. pylori was detected in the adjacent to the tumor GM in 84.5% of cases, of which a high degree of contamination was noted in 50.4% of the samples. Coccoid forms of H. pylori were detected in 93.4% of infected patients, and only coccoid-in 68.9%. It was found that a high degree of GM contamination by the coccoid forms of H. pylori was observed significantly more often in diffuse type of GC (P = 0.024), in poorly differentiated GC (P = 0.011), in stage T3-4 (P = 0.04) and in N1 (P = 0.011). In cases of moderate and marked concentrations of H. pylori in GM, a decrease in 10-year relapse free and overall survival from 55.6% to 26.3% was observed (P = 0.02 and P = 0.07, respectively). The relationship between the severity of the GM contamination by the spiral-shaped forms of H. pylori and the clinical and morphological characteristics and prognosis of GC was not revealed.

CONCLUSION

The data obtained indicates that H. pylori may be associated not only with induction but also with the progression of GC.

A retrospective study assessing the acceleration effect of type I Helicobacter pylori infection on the progress of atrophic gastritis

Based on the antibody typing classification, Helicobacter pylori infection can be divided into type I H. pylori infection and type II H. pylori infection. To observe the effects of different H. pylori infection types on the distribution of histopathological characteristics and the levels of three items of serum gastric function (PG I, PG II, G-17). 1175 cases from October 2018 to February 2020 were collected with ratio 1:2. All patients were performed with ¹⁴C-Urea breath test (¹⁴C-UBT), H. pylori antibody typing classification, three items of serum gastric function detection, painless gastroscopy, pathological examination, etc. According to H. pylori antibody typing classification, patients were divided into three groups: type I H. pylori infection group, type II H. pylori infection group and control group. Significant difference existed among type I H. pylori infection group, type II H. pylori infection group and control group in inflammation and activity (χ² = 165.43, 354.88, P all < 0.01). The proportion of three groups in OLGA staging had statistic difference (χ² = 67.99, P all < 0.01); Compared with type II H. pylori infection group and control group, the level of pepsinogen I, pepsinogen II, gastrin17 in type I H. pylori infection group increased, and PG I/PG II ratio (PG I/PG II ratio, PGR) decreased, which was statistically significant (χ² = 35.08, 166.24, 134.21, 141.19; P all < 0.01). Type I H. pylori infection worsened the severity of gastric mucosal inflammation and activity. H. pylori infection was prone to induce atrophy of gastric mucosa, while type I H. pylori infection played a key role in promoting the progress of atrophic gastritis and affected the level of serum gastric function. The study indicated that the eradication of H. pylori should be treated individually.

Apparent intracellular Helicobacter pylori detected by immunohistochemistry - the missing link in eradication failure

BACKGROUND

Helicobacter (H.) pylori is primarily an extracellularly living bacterium. However, seemingly intracellular occurrence can often be detected by immunohistochemical stains. Considering antimicrobial resistance, we investigated the impact of the apparent intracellular H. pylori (aiHp) on treatment failure of first-line triple therapies.

METHODS

Gastric biopsies of 814 H. pylori infected patients naïve for treatment were analyzed before and after eradication therapy by immunohistochemistry. Thereof, 373 received treatment consisting of amoxicillin, clarithromycin and PPI (AC/PPI). Availability of PCR-based clarithromycin susceptibility test results from pre-treatment gastric biopsies was a pre-condition for matching 52 aiHp to 52 non-aiHp cases within the AC/PPI-group.

RESULTS

AiHp were detected mostly in low counts predominantly in corpus, rarely in antrum biopsies (95.2% vs. 24.6%); they were found in 497 (61%) of all patients and in 192 of 373 patients (51.5%) in the AC/PPI-group. The eradication rate in aiHp vs. non-aiHp cases was 44.4% vs. 72.9% in the entire sample and 45.3% vs. 66.8% in the AC/PPI-group. Among the 104 paired patients, respective values were 46.2% vs. 78.8%; in clarithromycin susceptible cases 60.6% vs. 91.9%. Both aiHp and resistance to clarithromycin proved to be highly significant (p≤0.001) and independent predictors of eradication failure. Twelve of 13 aiHp cases with a clarithromycin sensitive strain, who failed eradication, developed resistance to the antibiotic.

CONCLUSIONS

AiHp found by immunohistochemical staining especially in corpus biopsies proved to be a risk factor for failure of first-line triple therapies; occurrence of aiHp should be considered with regard to therapy options.

Natural Products for the Prevention and Management of Helicobacter pylori Infection

Helicobacter pylori is the main pathogen that induces chronic gastritis, peptic ulcers, atrophic gastritis, and other gastric disorders, and it is classified as a group I carcinogen. To eradicate H. pylori infection, triple therapy consisting of two antibiotics and a proton pump inhibitor is the most widely recommended first-line therapeutic strategy. Antimicrobial resistance to antibiotics contained in triple therapy could lead to therapeutic regimen failures. Recent studies showed that many natural products, including fruits, vegetables, spices, and medicinal plants, possess inhibitory effects on H. pylori, indicating their potential to be alternatives to prevent and manage H. pylori infection. This review summarizes the effects of natural products on H. pylori infection and highlights the mechanisms of action.

Adhesion and Invasion of Gastric Mucosa Epithelial Cells by Helicobacter pylori

Helicobacter pylori is the main pathogenic bacterium involved in chronic gastritis and peptic ulcer and a class 1 carcinogen in gastric cancer. Current research focuses on the pathogenicity of H. pylori and the mechanism by which it colonizes the gastric mucosa. An increasing number of in vivo and in vitro studies demonstrate that H. pylori can invade and proliferate in epithelial cells, suggesting that this process might play an important role in disease induction, immune escape and chronic infection. Therefore, to explore the process and mechanism of adhesion and invasion of gastric mucosa epithelial cells by H. pylori is particularly important. This review examines the relevant studies and describes evidence regarding the adhesion to and invasion of gastric mucosa epithelial cells by H. pylori.

Why do we still have Helicobacter Pylori in our Stomachs

The existence of any infectious agent in a highly acidic human stomach is contentious, but the chance finding of Helicobacter pylori is by no means an accident. Once H. pylori colonises the gastric mucosa, it can persist for a lifetime, and it is intriguing why our immune system is able to tolerate its existence. Some conditions favour the persistence of H. pylori in the stomach, but other conditions oppose the colonisation of this bacterium. Populations with high and extremely low prevalence of H. pylori provide useful insights on the clinical outcomes that are associated with this type of infection. Adverse clinical outcomes including peptic ulcer disease and gastric cancer depend on a delicate balance between a harmless inflammation and a more severe kind of inflammation. Is the only good H. pylori really a dead H. pylori? The jury is still out.