Helicobacter pylori eradication: Exploring its impacts on the gastric mucosa

Exploring the Microbiome in Gastric Cancer: Assessing Potential Implications and Contextualizing Microorganisms beyond H. pylori and Epstein-Barr Virus

While previous research has primarily focused on the impact of H. pylori and Epstein-Barr virus (EBV), emerging evidence suggests that other microbial influences, including viral and fungal infections, may also contribute to gastric cancer (GC) development. The intricate interactions between these microbes and the host's immune response provide a more comprehensive understanding of gastric cancer pathogenesis, diagnosis, and treatment. The review highlights the roles of established players such as H. pylori and EBV and the potential impacts of gut bacteria, mainly Lactobacillus, Streptococcus, hepatitis B virus, hepatitis C virus, and fungi such as Candida albicans. Advanced sequencing technologies offer unprecedented insights into the complexities of the gastric microbiome, from microbial diversity to potential diagnostic applications. Furthermore, the review highlights the potential for advanced GC diagnosis and therapies through a better understanding of the gut microbiome.

Preoperative H. pylori Eradication Therapy Facilitates Precise Delineation in Early Gastric Cancer with Current H. pylori Infection

INTRODUCTION

Early gastric cancer with current Helicobacter pylori infection (HpC-EGC) is common, but it is still unclear whether H. pylori eradication therapy (Hp-ET) or endoscopic submucosal dissection (ESD) should be performed first. We evaluated Hp-ETs short-term effects on horizontal boundary delineations of HpC-EGC in ESD.

METHODS

Prospectively enrolled HpC-EGC patients were randomly assigned to eradication or control groups. Operation scopes of HpC-EGC lesions were delineated with marking dots at 5 mm out of the endoscopic demarcation line by an independent endoscopist, unaware of eradication status, before formal circumferential incision. As representatives, precise delineation rate, the shortest distance of all marking dots to the pathological demarcation line in all slices of one intact resected specimen (Dmin), and negative marking dot specimen rate were examined.

RESULTS

Twenty-three HpC-EGC patients (25 lesions) were allocated to eradication group and 26 patients (27 lesions) were allocated to the control group with similar eradication success rates and all were differentiated type. With improving background mucosa inflammation after Hp-ET and similar gastritis-like epithelium rates, 10 lesions (40.0%) in the eradication group were of precise delineation compared to control group with 2 lesions (7.4%) (relative risk = 5.40, 95% CI 1.31-22.28). Dmin of eradication and control groups were 4.17 ± 2.52 mm and 2.67 ± 2.30 mm (p = 0.029), accompanied by 4 (14.8%) and none (0.0%) specimens that exhibited positive marking dots (p = 0.11), respectively.

CONCLUSION

For HpC-EGC patients, administrating eradication medication before ESD is beneficial for the precise delineation of lesions and reducing the risk of positive horizontal resection margins.

Endoscopic characteristics and high-risk background mucosa factors of early gastric cancer after helicobacter pylori eradication: a single-center retrospective study

Purpose

Gastric cancer still develops after successful Helicobacter pylori(Hp)eradication. In this study, we aimed to explore the characteristics and risks of mucosal factors.

Methods

A total of 139 early gastric cancers (EGC) diagnosed in 133 patients after successful eradication from January 2016 to December 2021 were retrospectively included in the Hp-eradication EGC group and 170 EGCs diagnosed in 158 patients were included in the Hp-positive EGC group. We analyzed the clinical, pathological, and endoscopic characteristics between the two groups to identify the features of EGC after Hp eradication. Another 107 patients with no EGC after Hp eradication were enrolled in a Hp-eradication non-EGC group. The background mucosal factors between the Hp-eradication EGC group and the Hp-eradication non-EGC group were compared to analyze the high-risk background mucosal factors of EGC after eradication. In addition, we divided the EGC group after Hp eradication into IIc type and non-IIc type according to endoscopic gross classification to assess the high-risk background factors of IIc-type EGC after Hp eradication.

Results

The endoscopic features of EGC after Hp eradication included location in the lower part of the stomach (p=0.001), yellowish color (p= 0.031), and smaller size (p=0.001). The moderate/severe gastric atrophy (GA), intestinal metaplasia (IM) in the corpus, severe diffuse redness, and map-like redness were risk factors for EGC after eradication (p=0.001, p=0.001, p=0.001, and p= 0.005, respectively). The Kyoto classification total score in the EGC group was higher than the non-EGC group (4 vs.3 p<0.001). A multivariate analysis revealed that depressed erosion (OR=3.42, 95% CI 1.35-8.65, p= 0.009) was an independent risk factor for IIc-type EGC after Hp eradication.

Conclusion

EGC after eradication are smaller and yellowish lesions located in the lower part of the stomach. The risk background mucosal factors include moderate/severe GA, IM in the corpus, severe diffuse redness, and map-like redness. The Kyoto classification total score of 4 or more after successful eradication treatment might indicate EGC risk. In addition, the IIc-type EGC should be cautioned in the presence of depressed erosion after Hp eradication.

A ferroptosis-related gene in Helicobacter pylori infection, SOCS1, serves as a potential prognostic biomarker and corresponds with tumor immune infiltration in stomach adenocarcinoma: In silico approach

OBJECTIVE

Helicobacter pylori (H. pylori) is a major risk factor for the stomach adenocarcinoma (STAD). This study aimed to investigate the potential role of a H. pylori infection-related gene, SOCS1, in STAD.

MATERIALS AND METHODS

Online available databases were analyzed to determine the expression, correlations with clinicopathologic parameters, patients' survival, and immunological characteristics of SOCS1 in TCGA-STAD or GEO datasets. Univariate and multivariate Cox regression analyses were used to determine independent risk factors, which were further integrated to establish a nomogram. A comparison of drug sensitivity was conducted for the chemotherapy responses between individuals with low- and high-SOCS1. Prediction of tumor response to checkpoint inhibitors was based on the tumor immunodeficiency and exclusion (TIDE) score.

RESULTS

SOCS1 expression was significantly increased in both H. pylori-infected and STAD patients. Higher SOCS1 expression indicated an undesirable prognosis in STAD patients. SOCS1 upregulation was related to enhanced immune cell infiltrations and the upregulation of immune checkpoints in STAD patients. N stage, age and SOCS1 were identified as independent risk factors for higher mortality of STAD patients and confirmed using the nomogram. Drug sensitivity analyses demonstrated that high expression of SOCS1 in STAD patients could improve the sensitivity to chemotherapy. TIDE score showed that STAD patients with high SOCS1 expression would have superior response to immunotherapy.

CONCLUSIONS

SOCS1 may act as a potential biomarker for uncovering the underlying mechanisms of gastric cancer. Increasing the activity of immunotherapy through ferroptosis-immunomodulation may be a viable strategy in STAD therapy.

Development and validation of a convolutional neural network model for diagnosing Helicobacter pylori infections with endoscopic images: a multicenter study

BACKGROUND AND AIMS

Insufficient validation limits the generalizability of deep learning in diagnosing Helicobacter pylori infection with endoscopic images. The aim of this study was to develop a deep learning model for the diagnosis of H pylori infection using endoscopic images and validate the model with internal and external datasets.

METHODS

A convolutional neural network (CNN) model was developed based on a training dataset comprising 13,403 endoscopic images from 952 patients who underwent endoscopy at Seoul National University Hospital Gangnam Center. Internal validation was performed using a separate dataset comprised of images of 411 individuals of Korean descent and 131 of non-Korean descent. External validation was performed with the images of 160 patients in Gangnam Severance Hospital. Gradient-weighted class activation mapping was performed to visually explain the model.

RESULTS

In predicting H pylori ever-infected status, the sensitivity, specificity, and accuracy of internal validation for people of Korean descent were .96 (95% confidence interval [CI], .93-.98), .90 (95% CI, .85-.95), and .94 (95% CI, .91-.96), respectively. In the internal validation for people of non-Korean descent, the sensitivity, specificity, and accuracy in predicting H pylori ever-infected status were .92 (95% CI, .86-.98), .79 (95% CI, .67-.91), and .88 (95% CI, .82-.93), respectively. In the external validation cohort, sensitivity, specificity, and accuracy were .86 (95% CI, .80-.93), .88 (95% CI, .79-.96), and .87 (95% CI, .82-.92), respectively, when performing 2-group categorization. Gradient-weighted class activation mapping showed that the CNN model captured the characteristic findings of each group.

CONCLUSIONS

This CNN model for diagnosing H pylori infection showed good overall performance in internal and external validation datasets, particularly in categorizing patients into the never- versus ever-infected groups.

Microbiome and function alterations in the gastric mucosa of asymptomatic patients with Helicobacter pylori infection

BACKGROUND

Most patients with Helicobacter pylori (H. pylori) infection have no clinical symptoms, numerous studies reported the gastric microbiome in H. pylori-infected patients, but asymptomatic patients have not been distinguished. How the microbiome and function changes in asymptomatic patients with H. pylori infection remains poorly understood.

METHODS

A total of 29 patients were divided into H. pylori-infected asymptomatic group (10 patients), H. pylori-infected symptomatic group (11 patients) and H. pylori-uninfected group (8 patients). Gastric mucosa specimens were taken for histopathological examination, special staining, and 16 S rDNA sequencing. High-throughput results were evaluated by community composition analysis, indicator species analysis, alpha diversity analysis, beta diversity analysis, and function prediction.

RESULTS

The gastric microbiota composition at phylum and genus level of H. pylori-infected asymptomatic patients were similar with H. pylori-infected symptomatic group, but different from H. pylori-uninfected patients. The diversity and richness of gastric microbial community declined significantly in H. pylori-infected asymptomatic group comparing with H. pylori-uninfected group. Sphingomonas may be an indicator between symptomatic and asymptomatic patients with H. pylori infection, the AUC value of Sphingomonas is 0.79. Interactions between species increased and altered notably after H. pylori infection. More genera were affected by Helicobacter in H. pylori-infected asymptomatic patients. The function condition changed significantly in asymptomatic patients with H. pylori infection, there was no difference comparing with symptomatic ones. Amino acid metabolism and lipid metabolism strengthened but carbohydrate metabolism remained constant after H. pylori infection. The metabolism of fatty acid and bile acid was disturbed after infection with H. pylori.

CONCLUSION

The gastric microbiota composition and function mode changed significantly after H. pylori infection regardless of the presence of clinical symptoms, there was no difference between H. pylori-infected asymptomatic and symptomatic patients. The difference in gastric microbiota composition and interactions between species might be responsible for presence of digestive symptoms.

How Charge, Size and Protein Corona Modulate the Specific Activity of Nanostructured Lipid Carriers (NLC) against Helicobacter pylori

The major risk factor associated with the development of gastric cancer is chronic infection with Helicobacter pylori. The available treatments, based on a cocktail of antibiotics, fail in up to 40% of patients and disrupt their gut microbiota. The potential of blank nanostructured lipid carriers (NLC) for H. pylori eradication was previously demonstrated by us. However, the effect of NLC charge, size and protein corona on H. pylori-specific bactericidal activity herein studied was unknown at that time. All developed NLC formulations proved bactericidal against H. pylori. Although cationic NLC had 10-fold higher bactericidal activity than anionic NLC, they lacked specificity, since Lactobacillus acidophilus was also affected. Anionic NLC achieved complete clearance in both H. pylori morphologies (rod- and coccoid-shape) by inducing alterations in bacteria membranes and the cytoplasm, as visualized by transmission electron microscopy (TEM). The presence of an NLC protein corona, composed of 93% albumin, was confirmed by mass spectrometry. This protein corona delayed the bactericidal activity of anionic NLC against H. pylori and hindered NLC activity against Escherichia coli. Overall, these results sustain the use of NLC as a promising antibiotic-free strategy targeting H. pylori.

Characteristics and background mucosa status of early gastric cancer after Helicobacter pylori eradication: A narrative review

Helicobacter pylori (H pylori) eradication treatment can reduce the risk of gastric cancer. However, early gastric cancer (EGC) can still be detected after eradication. Meanwhile, EGC after eradication is challenging to diagnose by an endoscopist in some cases due to the lack of apparent characteristics and the complex mucosal status. This review aims to summarize the endoscopic and histological characteristics and the mucosal risk factors for gastric cancer after H pylori eradication. The literature was searched for possible reported gastric cancer after eradication in "PubMed." These included related clinical studies and reviews, and unrelated or non-English articles were excluded. Endoscopically, EGC displays a small, reddish and depressed lesion, indistinct border, "gastritis-like" appearance and submucosal invasion. Histologically, it is divided into surface differentiation, nontumorous epithelium, and intestinal type. The risk factors include severe gastric atrophy, intestinal metaplasia in the corpus, and map-like redness. In conclusion, these studies on the characteristics and risk mucosal factors of patients with gastric cancer after H pylori eradication will drive the establishment of a novel endoscopic surveillance and diagnosis system for H pylori-eradicated patients.

Detection and Characterization of Early Gastric Cancer

In this review, we would like to focus on risk stratification and quality indicators of diagnostic upper gastrointestinal endoscopy in the detection and characterization of early gastric cancer. Preparation of the upper gastrointestinal tract with mucolytic agents or simethicone is often overlooked in the west, and this inexpensive step prior to endoscopy can greatly improve the quality of imaging of the upper digestive tract. Risk stratification based on epidemiological features including family history, Helicobacter pylori infection status, and tobacco smoking is often overlooked but may be useful to identify a subgroup of patients at higher risk of developing gastric cancer. Quality indicators of diagnostic upper gastrointestinal endoscopy are now well defined and include: minimal inspection time of 3 min, adequate photographic documentation of upper gastrointestinal landmarks, utilization of advanced endoscopic imaging technology including narrow band imaging and blue laser imaging to detect intestinal metaplasia and characterize early gastric cancer; and standardized biopsy protocols allow for histological evaluation of gastric mucosa and detection of atrophic gastritis and intestinal metaplasia. Finally, endoscopic and histologic classifications such as the Kimura–Takemoto Classification of atrophic gastritis and the OLGA–OLGIM classifications may help stratify patients at a higher risk of developing early gastric cancer.

Surveillance strategies for precancerous gastric conditions after Helicobacter pylori eradication: There is still need for a tailored approach

Prevailing evidence declares that Helicobacter pylori (H. pylori) eradication therapy could shift precancerous gastric conditions (PGC) and positively confines gastric cancer (GC) risk during long-term endoscopic follow-up. Nonetheless, there is a yet unsolved controversy regarding the best-individualized surveillance strategies following H. pylori eradication, based on malignant risk stratification. This last dispute is due to the uncertainty of contemporary evidence and the role of H. pylori inflammatory changes in underestimating PGC at the index endoscopy. However, the current state of the art suggests that it is reasonable that high-quality endoscopy with histological assessment for the most accurate diagnosis of PGC may be delayed in selected high-risk patients without alarm signs for malignancy, following the eradication of H. pylori. Notwithstanding, these aspects need to be further examined in the next future to establish and optimize the most beneficial and cost-effective strategies for recognizing and managing H. pylori-positive patients with PGC in the short- and long-term follow-up. Accordingly, additional studies are yet required to sharpen the hazard stratification of patients with the greatest chance of GC evolution, also recognizing the evolving racial, ethnic, immigration factors and the necessity of novel biomarkers to limit GC development or accomplish a diagnosis of malignancy at an early stage.