Effect of the switch status of Helicobacter pylori outer inflammatory protein A on gastric diseases

Helicobacter pylori OipA (Outer Inflammatory Protein A) is an outer membrane protein that takes role in the adherence and colonization to the stomach. oipA gene expression is regulated by the slipped-strand mispairing mechanism through a hypermutable CT dinucleotide repeat motif in the 5΄ region. Alterations in the CT number repeats cause frame-shift mutations to result in phase variation of oipA expression. While a functional "On" status has been recognized as a risk factor for peptic ulcer diseases and gastric cancer in many studies, some controversial findings still exist. To this end, this study compiled the sequence data of oipA from 10 different studies between 2000-2019 and 50 oipA DNA sequences from our own research that examined the relationship between the phase On/Off status of oipA and gastric diseases based on CT repeat number. Overall, we have reached 536 oipA DNA sequences from patients. This large collection of oipA sequences first clarified the absolute conservation of the peptide-pentamer of FWLHA for phase ''On'' status, suggesting this pentamer as a superior marker for the determination of oipA status than counting the number of CT repeats. Combining the sequence and patient data, we have re-analyzed the association between the ''On'' status of oipA and gastric diseases. Our results showed a strong association between oipA ''On'' status and gastric cancer supporting previous findings. We also investigated the AlphaFold2 computed structure of OipA that adopts a beta-barrel fold closely resembling to the autotransporter family of H. pylori. Altogether, this study confirms a strong association between oipA ''On'' statuses and severe gastrointestinal diseases like cancer and provides useful insights into the FWLHA pentamer as an indicator of "On" status of oipA putative autotransporter function rather than CT repeats number.

Clinical value of serum pepsinogen in the diagnosis and treatment of gastric diseases

Pepsinogen, secreted from the gastric mucosa, is the precursor of pepsin. It is categorized as pepsinogen 1 and pepsinogen 2 based on its immunogenicity. The pepsinogen content that can enter the blood circulation through the capillaries of the gastric mucosa is approximately 1% and remains stable all the time. The pepsinogen content in serum will change with the pathological changes of gastric mucosa. Therefore, the level of pepsinogen in serum can play a role in serologic biopsy to reflect the function and morphology of different regions of gastric mucosa and serve as an indicator of gastric disease. This study conducts relevant research on serum pepsinogen 1, pepsinogen 2, and the ratio of pepsinogen 1 to pepsinogen 2, and reviews their important value in clinical diagnosis of Helicobacter pylori infection, gastric ulcer, and even gastric carcinoma, providing ideas for other researchers.

Helicobacter pylori infection affects the human gastric microbiome, as revealed by metagenomic sequencing

Helicobacter pylori infection is a prevalent infectious disease, associated with many gastric diseases, including gastritis, gastric ulcer, and gastric cancer. To reveal the characteristics of the gastric microbiome in patients infected with H. pylori, we performed metagenomic shotgun sequencing of stomach swab samples from 96 patients and then conducted metagenomic association analyses between alterations in the gastric microbiome and H. pylori infection status. The overall composition of the gastric microbiota in H. pylori‐infected individuals was distinctly different from the negative controls; H. pylori became the dominant species after colonizing the human stomach and significantly decreased the α‐diversity of the gastric community (P < 0.05, Wilcoxon rank‐sum test). We also identified 6 HPI‐associated microbial species (FDR < 0.05, Wilcoxon rank‐sum test): Stenotrophomonas maltophilia, Stenotrophomonas unclassified, Chryseobacterium unclassified, Pedobacter unclassified, Variovorax unclassified, and Pseudomonas stutzeri. Furthermore, 55 gastric microbial pathways were enriched in the H. pylori‐positive group, whereas only 2 pathways were more abundant in the H. pylori‐negative group: dTDP‐L‐rhamnose biosynthesis and tetrapyrrole biosynthesis (FDR < 0.05, Wilcoxon rank‐sum test). Gastritis was not associated with non‐H. pylori species in the stomach (P > 0.05, Wilcoxon rank‐sum test). This study revealed alterations in gastric microbial taxa and function associated with HPI in the Chinese population, which provides an insight into gastric microbial interactions and their potential role in the pathological process of gastric diseases.

Helicobacter pylori infection: How does age influence the inflammatory pattern?

The inflammatory pattern during Helicobacter pylori (H. pylori) infection is changeable and complex. During childhood, it is possible to observe a predominantly regulatory response, evidenced by high concentrations of key cytokines for the maintenance of Treg responses such as TGF-β1 and IL-10, in addition to high expression of the transcription factor FOXP3. On the other hand, there is a predominance of cytokines associated with the Th1 and Th17 responses among H. pylori-positive adults. In the last few years, the participation of the Th17 response in the gastric inflammation against H. pylori infection has been highlighted due to the high levels of TGF-β1 and IL-17 found in this infectious scenario, and growing evidence has supported a close relationship between this immune response profile and unfavorable outcomes related to the infection. Moreover, this cytokine profile might play a pivotal role in the effectiveness of anti-H. pylori vaccines. It is evident that age is one of the main factors influencing the gastric inflammatory pattern during the infection with H. pylori, and understanding the immune response against the bacterium can assist in the development of alternative prophylactic and therapeutic strategies against the infection as well as in the comprehension of the pathogenesis of the outcomes related to that microorganism.

Helicobacter delphinicola sp. nov., isolated from common bottlenose dolphins Tursiops truncatus with gastric diseases

Gastritis and gastric ulcers are well-recognized symptoms in cetaceans, and the genus Helicobacter is considered as the main cause. In this study, we examined the gastric fluid of captive common bottlenose dolphins Tursiops truncatus with gastric diseases in order to isolate the organisms responsible for diagnosis and treatment. Four Gram-negative, rod-shaped isolates (TSBT, TSH1, TSZ, and TSH3) with tightly coiled spirals with 2-4 turns and 2-6 bipolar, sheathed flagella, were obtained from gastric fluids of common bottlenose dolphins with gastric diseases. Phylogenetic analysis, based on 16S rRNA, atpA, and 60 kDa heat-shock protein (hsp60) genes, demonstrated that these isolates form a novel lineage within the genus Helicobacter. Analyses of 16S rRNA, atpA, and hsp60 gene sequences showed that isolate TSBT was most closely related to H. cetorum MIT99-5656T (98.5% similarity), H. pylori ATCC 43504T (76.7% similarity), and H. pylori ATCC 43504T (78.0% similarity), respectively. Type strains of Helicobacter showing resistance to 2% NaCl have not been reported previously; however, these novel isolates were resistant to 2% NaCl. Culture supernatant of some isolates induced intracellular vacuolization in mammalian cultured cells. These data, together with the different morphological and biochemical characteristics of the isolates, reveal that these isolates represent a novel species for which we propose the name Helicobacter delphinicola sp. nov. with type strain TSBT (= JCM 32789T = TSD-183T). Future studies will confirm whether H. delphinicola plays a role in lesion etiopathogenesis in cetaceans.

Diagnostic advances of artificial intelligence and radiomics in gastroenterology

Traditional medical imaging, including ultrasound, computed tomography, magnetic resonance imaging, or positron emission tomography, remains widely used diagnostic modalities for gastrointestinal diseases at present. These modalities are used to assess changes in morphology, attenuation, signal intensity, and enhancement characteristics. Gastrointestinal tumors, especially malignant tumors, are commonly seen in clinical practice with an increasing number of deaths each year. Because the imaging manifestations of different diseases usually overlap, accurate early diagnosis of tumor lesions, noninvasive and effective evaluation of tumor staging, and prediction of prognosis remain challenging. Fortunately, traditional medical images contain a great deal of important information that cannot be recognized by human eyes but can be extracted by artificial intelligence (AI) technology, which can quantitatively assess the heterogeneity of lesions and provide valuable information, including therapeutic effects and patient prognosis. With the development of computer technology, the combination of medical imaging and AI technology is considered to represent a promising field in medical image analysis. This new emerging field is called “radiomics”, which makes big data mining and extraction from medical imagery possible and can help clinicians make effective decisions and develop personalized treatment plans. Recently, AI and radiomics have been gradually applied to lesion detection, qualitative and quantitative diagnosis, histopathological grading and staging of tumors, therapeutic efficacy assessment, and prognosis evaluation. In this minireview, we briefly introduce the basic principles and technology of radiomics. Then, we review the research and application of AI and radiomics in gastrointestinal diseases, especially diagnostic advancements of radiomics in the differential diagnosis, treatment option, assessment of therapeutic efficacy, and prognosis evaluation of esophageal, gastric, hepatic, pancreatic, and colorectal diseases.

Astaxanthin Prevents Decreases in Superoxide Dismutase 2 Level and Superoxide Dismutase Activity in Helicobacter pylori-infected Gastric Epithelial Cells

Background

Helicobacter pylori increases production of reactive oxygen species (ROS), which activates inflammatory and carcinogenesis-related signaling pathways in gastric epithelial cells. Therefore, reducing ROS, by upregulating antioxidant enzyme, such as superoxide dismutase (SOD), may be a novel strategy to prevent H. pylori-associated gastric diseases. Astaxanthin is an antioxidant carotenoid that prevents oxidative stress-induced cell injury. The present study was aimed to determine whether H. pylori decreases SOD activity by changing the levels of SOD1/SOD2 and whether astaxanthin prevents changes in SOD levels and activity in H. pylori-infected gastric epithelial AGS cells.

Methods

AGS cells were pre-treated with astaxanthin for 3 hours prior to H. pylori infection and cultured for 1 hour in the presence of H. pylori. SOD levels and activity were assessed by Western blot analysis and a commercial assay kit, respectively. Mitochondrial ROS was determined using MitoSOX fluorescence.

Results

H. pylori decreased SOD activity and the SOD2 level, but increased mitochondrial ROS in AGS cells. The SOD1 level was not changed by H. pylori infection. Astaxanthin prevented H. pylori-induced decreases in the SOD2 level and SOD activity and reduced mitochondrial ROS in AGS cells.

Conclusions

Consumption of astaxanthin-rich food may prevent the development of H. pylori-associated gastric disorders by suppressing mitochondrial oxidative stress.

Assessment of dental caries and salivary nitric oxide levels in children with dyspepsia

BACKGROUND

The increase in nitric oxide (NO) levels in the oral cavity and saliva have been associated with various oral diseases; however, the gastro-salivary interaction of NO remains controversial. Thus, the aim of this study was to determine and compare salivary NO levels of dyspeptic and non-dyspeptic healthy children and to conduct an evaluation of its association with dental caries.

METHODS

Seventy children with dyspepsia (dyspeptic group) and 30 children without any gastrointestinal complaints (control group) were included in the study. Two biopsies from the gastric tissues were collected from dyspeptic children for histopathologic examination. Oral examination involved the assessment of dental caries, gingival index, plaque index, buffering capacity, salivary flow rate and pH. Salivary Streptococcus mutans (S. mutans) and Lactobacilli sp. counts were performed by commercial kits. For the comparison of the normal distribution between dyspeptic and control groups, Student t-test and for the comparison of the non-normal distribution, Kruskal-Wallis and Mann-Whitney-U tests were used. Chi-square test was used for comparison of qualitative data and the Pearson correlation test was used to evaluate the association between certain variables. Significance was assessed at p < 0.05 level.

RESULTS

Helicobacter pylori (H.pylori) were found in gastric biopsies of 84.2% (59/70) of the dyspeptic children. While the mean salivary NO values did not differ significantly between gastric H.pylori positive, negative and control groups, the salivary NO level of the dyspeptic group (213.7 ± 51.68 μmol/dL) was found to be significantly higher than the control group (185.7 ± 16.66 μmol/dL). No significant relationship was found between the mean salivary NO values, DMFT/dmft numbers and other oral parameters.

CONCLUSIONS

The association of dental caries and salivary NO levels could not be considered specific in the current study. Although there were no statistically significant differences between salivary NO levels of gastric H.pylori positive, gastric H.pylori negative and control groups, greater salivary NO levels among dyspeptic children compared with the control group demonstrated that the concentration of NO in the saliva could be used as a biological marker in dyspepsia, which could lead to the improvement of more specified, uncomplicated and susceptible methods for analysis.

The prevalence of Helicobacter pylori infection and other risk factors among Mongolian dyspeptic patients who have a high incidence and mortality rate of gastric cancer

BACKGROUND

Mongolia has not only the second highest incidence rate but also the highest mortality rate for gastric cancer globally. In addition to gastric cancer, ulcerative disease complications are also life threatening; thus, investigating Helicobacter pylori infection and other risk factors is essential.

RESULTS

H.pylori infection was high in tested dyspeptic patients from all parts of Mongolia, with an overall infection rate of 80.0%. Logistic regression analysis showed that H. pylori infection was associated with gastritis (odds ratio; 9.0 ([95% confidence interval 5.0-16.2]); p < 0.0001). H. pylori infection (3.3 [2.0-5.4]; p < 0.0001) and > 40 years old (1.5 [1.0-2.0]; p < 0.02) were both associated with atrophy. However, > 40 years old (3.8 [2.4-6.0]; p < 0.0001) and high salt intakes (1.6 [1.0-2.3]; p < 0.02), but not H. pylori infection, were associated with intestinal metaplasia. Excessive amount of salt usage was dramatically higher in northern and western parts of Mongolia, where precancerous diseases, such as erosive esophagitis (for cardia cancer), severe atrophy, and intestinal metaplasia (for non-cardia cancer), were highly prevalent.

CONCLUSIONS

H. pylori infection was the major gastric health problem among the Mongolian population. In addition, environmental factors such as high salt intake worsened the clinical outcome. Therefore, a nationwide screening and eradication of H. pylori infection as well as salt-reducing measures should be implemented.

Association between patient characteristics and magnetically controlled capsule endoscopy findings

BACKGROUND/AIM

Magnetically-controlled capsule endoscopy (MCE) is a potential option for the evaluation of gastric diseases in cases that are unsuited for conventional endoscopy, avoiding discomfort, sedation, and related complications. This retrospective study investigated associations between MCE findings and patient gender, age, and inpatient/outpatient status.

PATIENTS AND METHODS

The data of 580 consecutive patients who underwent MCE from 2015 to 2016 were analyzed. Data included age, gender, indication for MCE, inpatient/outpatient status, overall coverage of gastric anatomical landmarks, and comorbid conditions.

RESULTS

Compared with outpatients, inpatients had a higher rate of overall significant MCE findings (P = 0.014), polyp (P = 0.03), and ulceration (P = 0.003). MCE findings of the inpatient men and women were similar. Considering all patients, the percentage with ulceration was significantly higher in men than in women (P = 0.004), and men were younger (P < 0.001). Compared with younger patients, those aged ≥60 years had significantly higher rates of overall significant findings, mainly polyp and angiodysplasia.

CONCLUSIONS

Compared with outpatients, the inpatients showed higher overall significant findings. Men undergoing MCE were younger than the women, and more likely to have ulcerations. Older patients, whether outpatient or inpatient, had higher rates of significant findings, mainly polyp and angiodysplasia.

Challenges to the Treatment and New Perspectives for the Eradication of Helicobacter pylori

Helicobacter pylori (H. pylori) is one of the leading causes of gastric diseases such as chronic gastritis, peptic ulcer, and gastric adenocarcinoma. The current treatment of H. pylori infection with antibiotics and proton pump inhibitors has several limitations, including poor adherence and intrinsic patient-related factors, drug resistance, and the absence of adequate treatments. This review summarizes the current therapeutic approaches to eradicating H. pylori, the difficulties associated with its treatment, and several new perspectives aimed at improving existing treatment strategies.

Urease Inhibitory Activities of some Commonly Consumed Herbal Medicines

Urease enzyme has a crucial role in the persistent habitation of Helicobacter pylori (H. pylori) that induces gastrointestinal diseases, in particular gastritis, duodenal, peptic ulcer, and gastric cancer. Plants have long been utilized as the biggest source of substances with medicinal properties from natural origin and therefore result in less toxicity and adverse side effects upon usage. 15 medicinal plant extracts were examined against Jack bean urease activity by Berthelot reaction. Each herb was extracted using 80% aqueous methanol. The more effective extracts were further tested and their IC50 values were determined. Three plant extracts including Ginkgo biloba, Rhus coriaria, and Matricaria inodora were found to be the most effective ones with IC50 values of 36.17, 80.29, and 100.6 μg/mL, respectively.

Effect of Helicobacter pylori on gastric epithelial cells

The gastrointestinal epithelium has cells with features that make them a powerful line of defense in innate mucosal immunity. Features that allow gastrointestinal epithelial cells to contribute in innate defense include cell barrier integrity, cell turnover, autophagy, and innate immune responses. Helicobacter pylori (H. pylori) is a spiral shape gram negative bacterium that selectively colonizes the gastric epithelium of more than half of the world’s population. The infection invariably becomes persistent due to highly specialized mechanisms that facilitate H. pylori’s avoidance of this initial line of host defense as well as adaptive immune mechanisms. The host response is thus unsuccessful in clearing the infection and as a result becomes established as a persistent infection promoting chronic inflammation. In some individuals the associated inflammation contributes to ulcerogenesis or neoplasia. H. pylori has an array of different strategies to interact intimately with epithelial cells and manipulate their cellular processes and functions. Among the multiple aspects that H. pylori affects in gastric epithelial cells are their distribution of epithelial junctions, DNA damage, apoptosis, proliferation, stimulation of cytokine production, and cell transformation. Some of these processes are initiated as a result of the activation of signaling mechanisms activated on binding of H. pylori to cell surface receptors or via soluble virulence factors that gain access to the epithelium. The multiple responses by the epithelium to the infection contribute to pathogenesis associated with H. pylori.

Helicobacter pylori and gastric cancer: Indian enigma

Helicobacter pylori (H. pylori) is a gram negative microaerophilic bacterium which resides in the mucous linings of the stomach. It has been implicated in the causation of various gastric disorders including gastric cancer. The geographical distribution and etiology of gastric cancer differ widely in different geographical regions and H. pylori, despite being labeled as a grade I carcinogen, has not been found to be associated with gastric cancer in many areas. Studies in Asian countries such as Thailand, India, Bangladesh, Pakistan, Iran, Saudi Arabian countries, Israel and Malaysia, have reported a high frequency of H. pylori infection co-existing with a low incidence of gastric cancer. In India, a difference in the prevalence of H. pylori infection and gastric cancer has been noted even in different regions of the country leading to a puzzle when attempting to find the causes of these variations. This puzzle of H. pylori distribution and gastric cancer epidemiology is known as the Indian enigma. In this review we have attempted to explain the Indian enigma using evidence from various Indian studies and from around the globe. This review covers aspects of epidemiology, the various biological strains present in different parts of the country and within individuals, the status of different H. pylori-related diseases and the molecular pathogenesis of the bacterium.

Gastric diseases in Mongolian gerbils infected with different strains of Helicobacter pylori

Helicobacter pylori (H.pylori) is a bacterium responsible for one of the most widespread infections found in humans. It colonizes the gastric mucosa and can result in chronic gastritis and gastric cancer. The incidence of spontaneous gastric gastritis is low in Mongolian gerbils, and spontaneous H.pylori infection can not be detected in this animal. Since H.pylori-related gastric diseases in Mongolian gerbils are very similar to those in humans, they have been considered as ideal animals to establish H.pylori infection models. However, different strains of H.pylori may induce different types of pathologic changes in Mongolian gerbils. Clarification of the pathogenic mechanisms of different strains of H.pylori may provide a theoretical basis for screening appropriate H.pylori strains and directing individualized treatment in patients with H.pylori-related gastric diseases. In this paper, we review the recent progress in research of gastric diseases in Mongolian gerbils infected with different strains of H.pylori.

Molecular cross-talk between Helicobacter pylori and human gastric mucosa

Helicobacter pylori (H. pylori) has co-evolved with humans to be transmitted from person to person and to colonize the stomach persistently. A well-choreographed equilibrium between the bacterial effectors and host responses permits microbial persistence and health of the host, but confers a risk for serious diseases including gastric cancer. During its long coexistence with humans, H. pylori has developed complex strategies to limit the degree and extent of gastric mucosal damage and inflammation, as well as immune effector activity. The present editorial thus aims to introduce and comment on major advances in the rapidly developing area of H. pylori/human gastric mucosa interaction (and its pathological sequelae), which is the result of millennia of co-evolution of, and thus of reciprocal knowledge between, the pathogen and its human host.

In situ detection of Helicobacter pylori in gastric cancer and precancerous diseases and its significance

AIM: To investigate the distribution of H pylori infection in gastric cancer and precancerous diseases and the role of H pylori infection in the incidence and differentiation of gastric cancer, as well as the clinical value of H pylori infection detection using immunohistochemical method.

METHODS: Biopsy specimens of gastric mucosa in various diseases were randomly selected from 327 cases in Zhuanghe region in Liaoning Province, including 63 cases of superficial gastritis, 62 cases of atrophic gastritis and 202 cases of gastric cancer. HE staining and immunohistochemical staining were used to measure the density of H pylori infection in gastric mucosa and mucus.

RESULTS: The H pylori colonization status was higher in superficial gastritis group or in atrophic gastritis than gastric cancer group (χ² = 96.998, 87.542, both P < 0.01), while the status was lower in gastric cancer group than peri-cancer mucosa (χ² = 5.378, P < 0.01), higher in the intestinal gastric cancer group than in diffused gastric cancer (χ² = 19.253, P< 0.01). When H pylori density score was ≤ 2, the H pylori free status in superficial gastritis and atrophic gastritis were lower than that of gastric cancer (χ² = 6.526, 6.218, both P < 0.01), and when H pylori density score > 2, it was higher in superficial gastritis group or atrophic gastritis group than in gastric cancer group (χ² = 20.252, 46.248, both P < 0.01), it was higher in atrophic gastritis than in superficial gastritis (χ² = 4.746, P < 0.05), and it was higher in the intestinal gastric cancer than in diffused gastric cancer (χ² = 6.784, P < 0.01).

CONCLUSION: The H pylori distribution is higher in superficial gastritis and atrophic gastritis than in gastric cancer, lower in gastric cancer than in peri-cancer mucosa, higher in the intestinal gastric cancer than in diffused one. There is no significant difference in the free H pylori density score between gastric cancer tissue and peri-cancer mucosa. Immunohistochemical detection of H pylori is better than HE staining.

Application of magnifying endoscopy in diagnosis of gastric diseases

Micro-structure of gastrointestinal mucosa can be showed clearly by magnifying endoscopy. Magnifying endoscopy has unique advantage in diagnosis of gastrointestinal diseases, especially in gastric cancer and precancerous lesions. Some diseases, such as H. pylori-related gastritis, early gastric cancer, peptic ulcer, chronic atrophic gastritis and intestinal metaplasia in larger lesions, have characteristic performance under magnifying endoscopy. Magnifying endoscopic observation may improve the early diagnosis rate of these diseases.