Role of Flagella in the Pathogenesis of Helicobacter pylori

First insight into the whole genome sequence variations in clarithromycin resistant Helicobacter pylori clinical isolates in Russia

Clarithromycin (CLR) is currently a key antibiotic for Helicobacter pylori infection treatment, however, the data on CLR resistance patterns in Russia are missing. Here, we applied WGS-based approach to H. pylori clinical isolates from Russia to comprehensively investigate sequence variation, identify putative markers of CLR resistance and correlate them with phenotypic susceptibility testing. The phenotypic susceptibility of 44 H. pylori isolates (2014-2022) to CLR was determined by disc diffusion method: 23 isolates were CLR-resistant and 21-CLR-susceptible. All isolates were subjected to WGS and submitted to GenBank. Based on complete sequence analysis, we showed that among all sequence variants, the combination of mutations A2146G/A2147G in the 23S rRNA gene is the most reliable for prediction of phenotypic susceptibility. For the first time, the average number of mutations in 106 virulence-associated genes between resistant and susceptible groups were compared. Moreover, this study presents the first WGS insight into genetic diversity of H. pylori in Russia with a particular focus on the molecular basis of drug resistance: the novel mutations were described as potential markers for the resistance development. Of these, the most prominent was a frameshift deletion (252:CGGGT) in HP0820 coding region, which is a good candidate for further investigation.

Effect of Helicobacter pylori on sleeve gastrectomy and gastric microbiome differences in patients with obesity and diabetes

BACKGROUND

Obesity and diabetes mellitus (DM) have become public health concerns worldwide. Both conditions have severe consequences and are associated with significant medical costs and productivity loss. Additionally, Helicobacter pylori infection may be a risk factor for the development of these conditions. However, whether eradicating H. pylori infection directly causes weight loss or improves insulin sensitivity is unknown.

METHODS

In this study, we confirmed the effect of sleeve gastrectomy according to the state of the gastric microbiota in 40 patients with obesity, DM, and H. pylori infection. Patients with obesity were divided into four groups: non-DM without H. pylori infection (ND), non-DM with H. pylori infection (ND-HP), DM, and DM with H. pylori infection (DM-HP) using 16S V3-V4 sequencing.

RESULTS

In the DM group, ALT, hemoglobin, HbA1c, blood glucose, and HSI significantly decreased, whereas high-density lipoprotein significantly increased. However, in the H. pylori-positive group, no significant difference was observed. The diversity of gastric microbiota decreased in the order of the ND > DM > ND-HP > DM-HP groups. We also conducted a correlation analysis between the preoperative microbes and clinical data. In the ND-HP group, most of the top 20 gastric microbiota were negatively correlated with glucose metabolism. However, H. pylori infection was positively correlated with pre-insulin levels.

CONCLUSION

Therefore, these findings indicate that patients with obesity and diabetes clearly benefit from surgery, but H. pylori infection may also affect clinical improvement.

Cinnamaldehyde: An effective component of Cinnamomum cassia inhibiting Helicobacter pylori

ETHNOPHARMACOLOGICAL RELEVANCE

Cinnamomum cassia Presl (Cinnamomum cassia) is a common traditional Chinese medicine, which can promote the secretion and digestion of gastric juice, improve the function of gastrointestinal tract. Cinnamaldehyde (CA) is a synthetic food flavoring in the Chinese Pharmacopoeia.

AIM OF THE STUDY

This study aimed to search for the active ingredient (CA) of inhibiting H. pylori from Cinnamomum cassia, and elucidate mechanism of action, so as to provide the experimental basis for the treatment of H. pylori infection with Cinnamomum cassia.

MATERIALS AND METHODS

It's in vitro and in vivo pharmacological properties were evaluated based on minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and an acute gastric inflammation model in mice infected with H. pylori. Drug safety was evaluated using the CCK8 method and high-dose administration in mice. The advantageous characteristics of CA in inhibiting H. pylori were confirmed using acidic conditions and in combination with the antibiotics. The mechanism underlying the action of CA on H. pylori was explored using scanning electron microscopy (SEM), adhesion experiments, biofilm inhibition tests, ATP and ROS release experiments, and drug affinity responsive target stability (DARTS) screening of target proteins. The protein function and target genes were verified by molecular docking and Real-Time quantitative reverse transcription PCR (qRT-PCR).

RESULTS

The results demonstrated that CA was found to be the main active ingredient against H. pylori in Cinnamomum cassia in-vitro tests, with a MIC of 8-16 μg/mL. Moreover, CA effectively inhibited both sensitive and resistant H. pylori strains. The dual therapy of PPI + CA exhibited remarkable in vivo efficacy in the acute gastritis mouse model, superior to the standard triple therapy. DARTS, molecular docking, and qRT-PCR results suggested that the target sites of action were closely associated with GyrA, GyrB, AtpA, and TopA, which made DNA replication and transcription impossible, then leading to inhibition of bacterial adhesion and colonization, suppression of biofilm formation, and inhibition ATP and enhancing ROS.

CONCLUSIONS

This study demonstrated the suitability of CA as a promising lead drug against H. pylori, The main mechanisms can target GyrA ect, leading to reduce ATP and produce ROS, which induces the apoptosis of bacterial.

The bacterial flagellum as an object for optical trapping

This letter considers the possibility of using the optical trap to study the structure and function of the microbial flagellum. The structure of the flagellum of a typical gram-negative bacterium is described in brief. A standard mathematical model based on the principle of superposition is used to describe the movement of an ellipsoidal microbial cell in a liquid medium. The basic principles of optical trapping based on the combined action of the light pressure and the gradient force are briefly clarified. Several problems related to thermal damage of living microscopic objects when the latter gets to the focus of a laser beam are shortly discussed. It is shown that the probability of cell damage depends nonlinearly on the wavelength of laser radiation. Finally, the model systems that would make it possible to study flagella of the free bacteria and the ones anchored or tethered on the surface of a solid material are discussed in detail.

The application of organoids in cancers associated with pathogenic infections

Cancers associated with pathogen infections are gradually becoming important threats to human health globally, and it is of great significance to study the mechanisms of pathogen carcinogenesis. Current mechanistic studies rely on animal and two-dimensional (2D) cell culture models, but traditional methods have been proven insufficient for the rapid modeling of diseases caused by new pathogens. Therefore, research focus has shifted to organoid models, which can replicate the structural and genetic characteristics of the target tissues or organs in vitro, providing new platforms for the study of pathogen-induced oncogenic mechanisms. This review summarizes the application of organoid technology in the studies of four pathogen-associated cancers: gastric cancer linked to Helicobacter pylori, liver cancer associated with hepatitis B virus or hepatitis C virus, colorectal cancer caused by Escherichia coli, and cervical cancer related to human papillomavirus. This review also proposes several limitations of organoid technology to optimize organoid models and advance the treatment of cancer associated with pathogen infections in the future.

The Comparison of the Clinical Efficacy and Drug Tissue Distribution of Furazolidone and Tetracycline-quadruple Therapy in Helicobacter pylori Eradication: A Randomized Controlled Trial

OBJECTIVE

Helicobacter pylori (H. Pylori) is considered a main causative organism of gastric ulcers, gastric cancer and duodenal ulcers. The current treatment relies on a combination of antimicrobial agents and acid suppressant agents, but the eradication effect is not satisfactory. To clarify the concentration of antibiotics at the lesion site, we investigate the clinical efficacy and drug tissue distribution of the combination therapy of furazolidone and tetracycline in eradicating H. Pylori.

MATERIALS AND METHODS

Patients with H. pylori infection (n = 60) were randomized to either group A or B. Bismuth potassium citrate capsules 220 mg, omeprazole enteric-coated capsules 20 mg, amoxicillin capsules 1000 mg, each twice per day, and furazolidone tablets 500 mg were administered to group A. Group B was treated with bismuth potassium citrate capsules 220 mg, omeprazole enteric-coated capsules 20 mg, amoxicillin capsules 1000 mg, and tetracycline tablets 500 mg each twice per day for 2 weeks. The serum and gastric juice, gastric antrum, gastric horn, and gastric body samples were taken under a gastroscope on the 14th day. The antimicrobial concentrations in serum and tissue samples were determined by high-performance liquid chromatography.

RESULTS

In the negative group of furazolidone, the concentrations of gastric antrum, gastric body, and gastric angle were significantly higher than those in the positive group (P = 0.017, 0.015, and 0.028). The concentrations of furazolidone in gastric fluid, gastric antrum, gastric angle, and gastric body were ∼421 times, 82 times, 17 times, and 51 times higher than those in serum, respectively. The concentrations of tetracycline in the serum and gastric angle of the tetracycline negative group were significantly higher than those in the positive group (P = 0.036 and 0.042), and the tetracycline concentrations in the gastric horn and gastric body were about 4 and 6 times higher than those in the serum, respectively. The concentration of amoxicillin in group B was higher than that in group A, especially in serum, gastric juice, gastric angle, and gastric body (P < 0.05).

CONCLUSION

Furazolidone is mainly concentrated and sequentially distributed in gastric juice, gastric antrum, and gastric body tissue, and tetracycline is mainly distributed in serum, gastric angle, and gastric body, whereas amoxicillin is mainly distributed in serum, gastric juice, gastric angle, and gastric body. Improving the concentration and tissue distribution of antibacterial drugs in the human gastric mucosa is the key to ensuring the ideal eradication rate of quadruple therapy.

Machine Learning-Based Prediction of Helicobacter pylori Infection Study in Adults

BACKGROUND Helicobacter pylori has a high infection rate worldwide, and epidemiological study of H. pylori is important. Artificial intelligence has been widely used in the field of medical research and has become a hotspot in recent years. This paper proposed a prediction model for H. pylori infection based on machine learning in adults. MATERIAL AND METHODS Adult patients were selected as research participants, and information on 30 factors was collected. The chi-square test, mutual information, ReliefF, and information gain were used to screen the feature factors and establish 2 subsets. We constructed an H. pylori infection prediction model based on XGBoost and optimized the model using a grid search by analyzing the correlation between features. The performance of the model was assessed by comparing its accuracy, recall, precision, F1 score, and AUC with those of 4 other classical machine learning methods. RESULTS The model performed better on the part B subset than on the part A subset. Compared with the other 4 machine learning methods, the model had the highest accuracy, recall, F1 score, and AUC. SHAP was used to evaluate the importance of features in the model. It was found that H. pylori infection of family members, living in rural areas, poor washing hands before meals and after using the toilet were risk factors for H. pylori infection. CONCLUSIONS The model proposed in this paper is superior to other models in predicting H. pylori infection and can provide a scientific basis for identifying the population susceptible to H. pylori and preventing H. pylori infection.

Helicobacter pylori Outer Membrane Proteins and Virulence Factors: Potential Targets for Novel Therapies and Vaccines

Helicobacter pylori is a gastric oncopathogen that infects over half of the world's human population. It is a Gram-negative, microaerophilic, helix-shaped bacterium that is equipped with flagella, which provide high motility. Colonization of the stomach is asymptomatic in up to 90% of people but is a recognized risk factor for developing various gastric disorders such as gastric ulcers, gastric cancer and gastritis. Invasion of the human stomach occurs via numerous virulence factors such as CagA and VacA. Similarly, outer membrane proteins (OMPs) play an important role in H. pylori pathogenicity as a means to adapt to the epithelial environment and thereby facilitate infection. While some OMPs are porins, others are adhesins. The epithelial cell receptors SabA, BabA, AlpA, OipA, HopQ and HopZ have been extensively researched to evaluate their epidemiology, structure, role and genes. Moreover, numerous studies have been performed to seek to understand the complex relationship between these factors and gastric diseases. Associations exist between different H. pylori virulence factors, the co-expression of which appears to boost the pathogenicity of the bacterium. Improved knowledge of OMPs is a major step towards combatting this global disease. Here, we provide a current overview of different H. pylori OMPs and discuss their pathogenicity, epidemiology and correlation with various gastric diseases.

Intravenous Antibiotics in the Management of H. pylori Infection: A Systematic Review

Background: Helicobacter pylori is implicated in the development of gastritis, ulcers, and various gastric cancers, representing significant morbidity, mortality, and healthcare spending. Patients with H. pylori infection have traditionally been treated with oral antibiotics, however, oral therapy is not feasible in all clinical situations. We examined the available evidence supporting the use of intravenous (IV) antibiotics in H. pylori. Methods: This systematic review was carried out by reviewing multiple electronic databases: MEDLINE, CENTRAL, EMBASE, CINAHL, Clinicaltrials.org, and the World Health Organization (WHO) database of clinical trials. Articles published from database inception until February 12, 2023 that discussed the use of IV antibiotics in H. pylori management were included. Results: The search strategy identified 978 studies, with 11 meeting the inclusion criteria. The results demonstrate that there is a lack of robust trials examining the use of IV antibiotics in H. pylori management. Many trials demonstrated that IV antibiotics were safe and efficacious but the results are limited by inconsistencies in the year and geographic location trials were conducted, the IV and oral antibiotic regimens, and the duration of therapy. Conclusions: IV antibiotics appear to be a feasible therapeutic alternative in the management of H. pylori and can be considered, especially in patient populations where oral therapy is contraindicated.

Infiltration to infection: key virulence players of Helicobacter pylori pathogenicity

PURPOSE

This study aims to comprehensively review the multifaceted factors underlying the successful colonization and infection process of Helicobacter pylori (H. pylori), a prominent Gram-negative pathogen in humans. The focus is on elucidating the functions, mechanisms, genetic regulation, and potential cross-interactions of these elements.

METHODS

Employing a literature review approach, this study examines the intricate interactions between H. pylori and its host. It delves into virulence factors like VacA, CagA, DupA, Urease, along with phase variable genes, such as babA, babC, hopZ, etc., giving insights about the bacterial perspective of the infection The association of these factors with the infection has also been added in the form of statistical data via Funnel and Forest plots, citing the potential of the virulence and also adding an aspect of geographical biasness to the virulence factors. The biochemical characteristics and clinical relevance of these factors and their effects on host cells are individually examined, both comprehensively and statistically.

RESULTS

H. pylori is a Gram-negative, spiral bacterium that successfully colonises the stomach of more than half of the world's population, causing peptic ulcers, gastric cancer, MALT lymphoma, and other gastro-duodenal disorders. The clinical outcomes of H. pylori infection are influenced by a complex interplay between virulence factors and phase variable genes produced by the infecting strain and the host genetic background. A meta-analysis of the prevalence of all the major virulence factors has also been appended.

CONCLUSION

This study illuminates the diverse elements contributing to H. pylori's colonization and infection. The interplay between virulence factors, phase variable genes, and host genetics determines the outcome of the infection. Despite biochemical insights into many factors, their comprehensive regulation remains an understudied area. By offering a panoramic view of these factors and their functions, this study enhances understanding of the bacterium's perspective, i.e. H. pylori's journey from infiltration to successful establishment within the host's stomach.

Differential cytokine expression in gastric tissues highlights helicobacter pylori's role in gastritis

Helicobacter pylori (H. pylori), known for causing gastric inflammation, gastritis and gastric cancer, prompted our study to investigate the differential expression of cytokines in gastric tissues, which is crucial for understanding H. pylori infection and its potential progression to gastric cancer. Focusing on Il-1β, IL-6, IL-8, IL-12, IL-18, and TNF-α, we analysed gene and protein levels to differentiate between H. pylori-infected and non-infected gastritis. We utilised real-time quantitative polymerase chain reaction (RT-qPCR) for gene quantification, immunohistochemical staining, and ELISA for protein measurement. Gastric samples from patients with gastritis were divided into three groups: (1) non-gastritis (N-group) group, (2) gastritis without H. pylori infection (G-group), and (3) gastritis with H. pylori infection (GH-group), each consisting of 8 samples. Our findings revealed a statistically significant variation in cytokine expression. Generally, cytokine levels were higher in gastritis, but in H. pylori-infected gastritis, IL-1β, IL-6, and IL-8 levels were lower compared to H. pylori-independent gastritis, while IL-12, IL-18, and TNF-α levels were higher. This distinct cytokine expression pattern in H. pylori-infected gastritis underscores a unique inflammatory response, providing deeper insights into its pathogenesis.

ASSESSMENT OF THE ACCURACY OF THE RAPID TEST FOR THE DIAGNOSIS OF HELICOBACTER PYLORI IN PATIENTS THAT DIDN'T UNDERGO PREVIOUS ERADICATION THERAPY AND WHO WENT THROUGH ENDOSCOPY

BACKGROUND

Helicobacter pylori infection is widely spread globally and is known to cause potentially serious diseases. Several diagnostic methods exist to identify and treat carriers of this bacterium. Serological tests for the diagnosis of infection are based on the detection of antibodies immunoglobulin G against H. pylori, a non-invasive, inexpensive, and easy-to-perform option.

OBJECTIVE

This research aims to ascertain the accuracy of an immunochromatographic serological test to verify the feasibility of using this method in patients who have not undergone previous eradication therapy.

METHODS

Rapid tests and questionnaires were applied to 53 patients that underwent upper digestive endoscopy with research for H. pylori between the period of September and October 2021. The results were compared with histopathology.

RESULTS

In the rapid tests, seven positive and 46 negative results were obtained. When compared with the gold stan-dard, the following values were described: sensitivity 54.5%, specificity 97.6%, positive predictive value 85.7%, and negative predictive value 89.1%.

CONCLUSION

In the present study, the immunochromatographic serological tests had an accuracy close to the values found in other similar studies. Therefore, it may be concluded that the rapid serological test remains a reasonable choice for screening large populations due to its low cost and ease of application, especially in those individuals who have not undergone previous treatment.

BACKGROUND

• Helicobacter pylori infection can cause potentially serious diseases.

BACKGROUND

• Serological tests are based on the detection of antibodies immunoglobulin G against Helicobacter pylori.

BACKGROUND

• Serological tests for the diagnosis of Helicobacter pylori infection are low cost tools and have easy application.

BACKGROUND

• Rapid serological test is a reasonable choice for screening large populations.

Pangenome Analysis of Helicobacter pylori Isolates from Selected Areas of Africa Indicated Diverse Antibiotic Resistance and Virulence Genes

The challenge facing Helicobacter pylori (H. pylori) infection management in some parts of Africa is the evolution of drug-resistant species, the lack of gold standard in diagnostic methods, and the ineffectiveness of current vaccines against the bacteria. It is being established that even though clinical consequences linked to the bacteria vary geographically, there is rather a generic approach to treatment. This situation has remained problematic in the successful fight against the bacteria in parts of Africa. As a result, this study compared the genomes of selected H. pylori isolates from selected areas of Africa and evaluated their virulence and antibiotic drug resistance, those that are highly pathogenic and are associated with specific clinical outcomes and those that are less virulent and rarely associated with clinical outcomes. 146 genomes of H. pylori isolated from selected locations of Africa were sampled, and bioinformatic tools such as Abricate, CARD RGI, MLST, Prokka, Roary, Phandango, Google Sheets, and iTOLS were used to compare the isolates and their antibiotic resistance or susceptibility. Over 20 k virulence and AMR genes were observed. About 95% of the isolates were genetically diverse, 90% of the isolates harbored shell genes, and 50% harbored cloud and core genes. Some isolates did not retain the cagA and vacA genes. Clarithromycin, metronidazole, amoxicillin, and tinidazole were resistant to most AMR genes (vacA, cagA, oip, and bab). Conclusion. This study found both virulence and AMR genes in all H. pylori strains in all the selected geographies around Africa with differing quantities. MLST, Pangenome, and ORF analyses showed disparities among the isolates. This in general could imply diversities in terms of genetics, evolution, and protein production. Therefore, generic administration of antibiotics such as clarithromycin, amoxicillin, and erythromycin as treatment methods in the African subregion could be contributing to the spread of the bacterium's antibiotic resistance.

Strategies of Helicobacter pylori in evading host innate and adaptive immunity: insights and prospects for therapeutic targeting

Helicobacter pylori (H. pylori) is the predominant pathogen causing chronic gastric mucosal infections globally. During the period from 2011 to 2022, the global prevalence of H. pylori infection was estimated at 43.1%, while in China, it was slightly higher at approximately 44.2%. Persistent colonization by H. pylori can lead to gastritis, peptic ulcers, and malignancies such as mucosa-associated lymphoid tissue (MALT) lymphomas and gastric adenocarcinomas. Despite eliciting robust immune responses from the host, H. pylori thrives in the gastric mucosa by modulating host immunity, particularly by altering the functions of innate and adaptive immune cells, and dampening inflammatory responses adverse to its survival, posing challenges to clinical management. The interaction between H. pylori and host immune defenses is intricate, involving evasion of host recognition by modifying surface molecules, manipulating macrophage functionality, and modulating T cell responses to evade immune surveillance. This review analyzes the immunopathogenic and immune evasion mechanisms of H. pylori, underscoring the importance of identifying new therapeutic targets and developing effective treatment strategies, and discusses how the development of vaccines against H. pylori offers new hope for eradicating such infections.

Helicobacter pylori FlgN binds its substrate FlgK and the flagellum ATPase FliI in a similar manner observed for the FliT chaperone

In bacterial flagellum biogenesis, secretion of the hook-filament junction proteins FlgK and FlgL and completion of the flagellum requires the FlgN chaperone. Similarly, the related FliT chaperone is necessary for the secretion of the filament cap protein FliD and binds the flagellar export gate protein FlhA and the flagellum ATPase FliI. FlgN and FliT require FliJ for effective substrate secretion. In Helicobacter pylori, neither FlgN, FliT, nor FliJ have been annotated. We demonstrate that the genome location of HP1120 is identical to that of flgN in other flagellated bacteria and that HP1120 is the homolog of Campylobacter jejuni FlgN. A modeled HP1120 structure contains three α-helices and resembles the FliT chaperone, sharing a similar substrate-binding pocket. Using pulldowns and thermophoresis, we show that both HP1120 and a HP1120Δ126-144 deletion mutant bind to FlgK with nanomolar affinity, but not to the filament cap protein FliD, confirming that HP1120 is FlgN. Based on size-exclusion chromatography and multi-angle light scattering, H. pylori FlgN binds to FlgK with 1:1 stoichiometry. Overall structural similarities between FlgN and FliT suggest that substrate recognition on FlgN primarily involves an antiparallel coiled-coil interface between the third helix of FlgN and the C-terminal helix of the substrate. A FlgNΔ126-144 N100A, Y103A, S111I triple mutant targeting this interface significantly impairs the binding of FlgK. Finally, we demonstrate that FlgNΔ126-144 , like FliT, binds with sub-micromolar affinity to the flagellum ATPase FliI or its N-terminal domain. Hence FlgN and FliT likely couple delivery of low-abundance export substrates to the flagellum ATPase FliI.

Phylogenetic analysis of pathogenic genes in Helicobacter species

BACKGROUND

Helicobacter bacteria are associated with gastrointestinal diseases, especially Helicobacter pylori (H. pylori). With the isolation of many non-Helicobacter pylori Helicobacters (NHPH) from the liver, intestines, and gallbladder of natural animal reservoirs, NHPH have been potential zoonotic pathogens, but their infection and pathogenic mechanisms are still unclear.

AIM

To explore the phylogenetic relationship of Helicobacter species based on their pathogenic genes.

METHODS

The present study collected the genomic sequences of 50 strains in genus Helicobacter, including 12 strains of H. pylori and 38 strains of NHPH. Based on 16S rRNA gene and several pathogenic genes (flagella, urease, and virulence factors), MAGA software (Version 11.0) was used to align their sequences and construct phylogenetic trees.

RESULTS

The phylogenetic tree of 16S rRNA gene showed that gastric Helicobacter (GH) and enterohepatic Helicobacter species (EHS) were clustered into two large branches, respectively. All of the GH's hosts were mammals, while the hosts of EHS were many wild poultry and mammals. Based on the flagella motility-related genes (flaA, flaB, fliP, fliQ, fliR, fliG, fliM, and fliN), the phylogenetic trees were divided into two major branches (GH and EHS). Similarly, the phylogenetic trees of lipopolysaccharide (LPS) biosynthesis-related genes (lptA, waaC, and waaF) presented two major branches (GH and EHS), too. The urease genes existed in all of the 12 strains of H. pylori, 13 strains of gastric NHPH, and 4 strains of EHS (H. hepaticus, H. muridarum, H. bilis, and H. anseris). However, no significant phylogenetic patterns of GH and EHS were observed in the seven urease genes (ureA, ureB, ureE, ureF, ureG, ureH, and ureI).

CONCLUSION

The phylogenetic relationship of Helicobacter species' pathogenic genes is dominated distinctly by the special colonization areas including gastric and enterohepatic niches.

Helicobacter pylori: A Contemporary Perspective on Pathogenesis, Diagnosis and Treatment Strategies

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that colonizes the gastric mucosa and is associated with various gastrointestinal disorders. H. pylori is a pervasive pathogen, infecting nearly 50% of the world's population, and presents a substantial concern due to its link with gastric cancer, ranking as the third most common cause of global cancer-related mortality. This review article provides an updated and comprehensive overview of the current understanding of H. pylori infection, focusing on its pathogenesis, diagnosis, and treatment strategies. The intricate mechanisms underlying its pathogenesis, including the virulence factors and host interactions, are discussed in detail. The diagnostic methods, ranging from the traditional techniques to the advanced molecular approaches, are explored, highlighting their strengths and limitations. The evolving landscape of treatment strategies, including antibiotic regimens and emerging therapeutic approaches, is thoroughly examined. Through a critical synthesis of the recent research findings, this article offers valuable insights into the contemporary knowledge of Helicobacter pylori infection, guiding both clinicians and researchers toward effective management and future directions in combating this global health challenge.

Helicobacter pylori antigens as immunomodulators of immune system

Helicobacter pylori (H. pylori) is one of the most prevalent human pathogens and the leading cause of chronic infection in almost half of the population in the world (~59%). The bacterium is a major leading cause of chronic gastritis, gastric and duodenal ulcers, and two type of malignancies, gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. Despite the immune responses mounted by the host, the bacteria are not cleared from the body resulting in a chronic infection accompanied by a chronic inflammation. Herein, a review of the literature discussing H. pylori antigens modulating the immune responses is presented. The mechanisms that are involved in the modulation of innate immune response, include modulation of recognition by pattern recognition receptors (PRRs) such as modulation of recognition by toll like receptors (TLR)4 and TLR5, modulation of phagocytic function, and modulation of phagocytic killing mediated by reactive oxygen species (ROS) and nitric oxide (NO). On the other hands, H. pylori modulates acquired immune response by the induction of tolerogenic dendritic cells (DCs), modulation of apoptosis, induction of regulatory T cells, modulation of T helper (Th)1 response, and modulation of Th17 response.

Microparticles and nanoparticles-based approaches to improve oral treatment of Helicobacter pylori infection

Helicobacter pylori is a gram-negative, spiral-shaped, flagellated bacterium that colonizes the stomach of half the world's population. Helicobacter pylori infection causes pathologies of varying severity. Standard oral therapy fails in 15-20% since the barriers of the oral route decrease the bioavailability of antibiotics and the intrinsic factors of bacteria increase the rates of resistance. Nanoparticles and microparticles are promising strategies for drug delivery into the gastric mucosa and targeting H. pylori. The variety of building blocks creates systems with distinct colloidal, surface, and biological properties. These features improve drug-pathogen interactions, eliminate drug depletion and overuse, and enable the association of multiple actives combating H. pylori on several fronts. Nanoparticles and microparticles are successfully used to overcome the barriers of the oral route, physicochemical inconveniences, and lack of selectivity of current therapy. They have proven efficient in employing promising anti-H. pylori compounds whose limitation is oral route instability, such as some antibiotics and natural products. However, the current challenge is the applicability of these strategies in clinical practice. For this reason, strategies employing a rational design are necessary, including in the development of nano- and microsystems for the oral route.

Motility provides specific adhesion patterns and improves Listeria monocytogenes invasion into human HEp-2 cells

Listeria monocytogenes is motile at 22°C and non-motile at 37°C. In contrast, expression of L. monocytogenes virulence factors is low at 22°C and up-regulated at 37°C. Here, we studied a character of L. monocytogenes near surface swimming (NSS) motility and its effects on adhesion patterns and invasion into epithelial cells. L. monocytogenes and its saprophytic counterpart L. innocua both grown at 22°C showed similar NSS characteristics including individual velocities, trajectory lengths, residence times, and an asymmetric distribution of velocity directions. Similar NSS patterns correlated with similar adhesion patterns. Motile bacteria, including both pathogenic and saprophytic species, showed a preference for adhering to the periphery of epithelial HEp-2 cells. In contrast, non-motile bacteria were evenly distributed across the cell surface, including areas over the nucleus. However, the uneven distribution of motile bacteria did not enhance the invasion into HEp-2 cells unless virulence factor production was up-regulated by the transient shift of the culture to 37°C. Motile L. monocytogenes grown overnight at 22°C and then shifted to 37°C for 2 h expressed invasion factors at the same level and invaded human cells up to five times more efficiently comparatively with non-motile bacteria grown overnight at 37°C. Taken together, obtained results demonstrated that (i) NSS motility and correspondent peripheral location over the cell surface did not depend on L. monocytogenes virulence traits; (ii) motility improved L. monocytogenes invasion into human HEp-2 cells within a few hours after the transition from the ambient temperature to the human body temperature.

Helicobacter pylori in the post-antibiotics era: from virulence factors to new drug targets and therapeutic agents

Helicobacter pylori is considered one of the most prevalent human pathogenic microbes globally. It is the main cause of a number of gastrointestinal ailments, including peptic and duodenal ulcers, and gastric tumors with high mortality rates. Thus, eradication of H. pylori is necessary to prevent gastric cancer. Still, the rise in antibiotic resistance is the most important challenge for eradication strategies. Better consideration of H. pylori virulence factors, pathogenesis, and resistance is required for better eradication rates and, thus, prevention of gastrointestinal malignancy. This article is aimed to show the role of virulence factors of H. pylori. Some are involved in its survival in the harsh environment of the human gastric lumen, and others are related to pathogenesis and the infection process. Furthermore, this work has highlighted the recent advancement in H. pylori treatment, as well as antibiotic resistance as a main challenge in H. pylori eradication. Also, we tried to provide an updated summary of the evolving H. pylori control strategies and the potential alternative drugs to fight this lethal resistant pathogen. Recent studies have focused on evaluating the efficacy of alternative regimens (such as sequential, hybrid, concomitant treatment, vonoprazan (VPZ)-based triple therapy, high-dose PPI-amoxicillin dual therapy, probiotics augmented triple therapy, or in combination with BQT) in the effective eradication of H. pylori. Thus, innovating new anti-H. pylori drugs and establishing H. pylori databanks are upcoming necessities in the near future.

Phages on filaments: A genetic screen elucidates the complex interactions between Salmonella enterica flagellin and bacteriophage Chi

The bacterial flagellum is a rotary motor organelle and important virulence factor that propels motile pathogenic bacteria, such as Salmonella enterica, through their surroundings. Bacteriophages, or phages, are viruses that solely infect bacteria. As such, phages have myriad applications in the healthcare field, including phage therapy against antibiotic-resistant bacterial pathogens. Bacteriophage χ (Chi) is a flagellum-dependent (flagellotropic) bacteriophage, which begins its infection cycle by attaching its long tail fiber to the S. enterica flagellar filament as its primary receptor. The interactions between phage and flagellum are poorly understood, as are the reasons that χ only kills certain Salmonella serotypes while others entirely evade phage infection. In this study, we used molecular cloning, targeted mutagenesis, heterologous flagellin expression, and phage-host interaction assays to determine which domains within the flagellar filament protein flagellin mediate this complex interaction. We identified the antigenic N- and C-terminal D2 domains as essential for phage χ binding, with the hypervariable central D3 domain playing a less crucial role. Here, we report that the primary structure of the Salmonella flagellin D2 domains is the major determinant of χ adhesion. The phage susceptibility of a strain is directly tied to these domains. We additionally uncovered important information about flagellar function. The central and most variable domain, D3, is not required for motility in S. Typhimurium 14028s, as it can be deleted or its sequence composition can be significantly altered with minimal impacts on motility. Further knowledge about the complex interactions between flagellotropic phage χ and its primary bacterial receptor may allow genetic engineering of its host range for use as targeted antimicrobial therapy against motile pathogens of the χ-host genera Salmonella, Escherichia, or Serratia.

Biofilm of Helicobacter pylori: Life Cycle, Features, and Treatment Options

Helicobacter pylori is a gastric pathogen that infects nearly half of the global population and is recognized as a group 1 carcinogen by the Word Health Organization. The global rise in antibiotic resistance has increased clinical challenges in treating H. pylori infections. Biofilm growth has been proposed to contribute to H. pylori's chronic colonization of the host stomach, treatment failures, and the eventual development of gastric diseases. Several components of H. pylori have been identified to promote biofilm growth, and several of these may also facilitate antibiotic tolerance, including the extracellular matrix, outer membrane proteins, shifted morphology, modulated metabolism, efflux pumps, and virulence factors. Recent developments in therapeutic approaches targeting H. pylori biofilm have shown that synthetic compounds, such as small molecule drugs and plant-derived compounds, are effective at eradicating H. pylori biofilms. These combined topics highlight the necessity for biofilm-based research in H. pylori, to improve current H. pylori-targeted therapeutic approaches and alleviate relative public health burden. In this review we discuss recent discoveries that have decoded the life cycle of H. pylori biofilms and current biofilm-targeted treatment strategies.

Histopathological Evaluation of Gastric Mucosal Atrophy for Predicting Gastric Cancer Risk: Problems and Solutions

Patients suffering from chronic gastritis and developing gastric mucosa atrophy are at increased risk of the development of gastric cancer. The diagnosis of chronic atrophic gastritis (CAG) is a complex procedure involving a detailed history taking, a thorough physical examination and the use of laboratory and instrumental diagnostic methods among which the endoscopy of the upper digestive tract is the cornerstone because it allows the assessment of the topography of gastritis and identification of erosions and areas of intestinal metaplasia with the use of NBI endoscopy. However, the diagnosis of CAG requires morphological examination of the gastric mucosa. So, in addition to assessing macroscopic changes in the gastric mucosa, it is necessary to take biopsy specimens in accordance with the protocols for their morphological and immunohistochemical examination. In the absence of specific diagnostic stigmas of CAG, close cooperation between a clinician, endoscopist and pathologist is necessary. The article presents systematized data on the histopathological assessment of the gastric mucosa atrophy to predict the risk of gastric cancer.

The interactions of Candida albicans with gut bacteria: a new strategy to prevent and treat invasive intestinal candidiasis

BACKGROUND

The gut microbiota plays an important role in human health, as it can affect host immunity and susceptibility to infectious diseases. Invasive intestinal candidiasis is strongly associated with gut microbiota homeostasis. However, the nature of the interaction between Candida albicans and gut bacteria remains unclear.

OBJECTIVE

This review aimed to determine the nature of interaction and the effects of gut bacteria on C. albicans so as to comprehend an approach to reducing intestinal invasive infection by C. albicans.

METHODS

This review examined 11 common gut bacteria's interactions with C. albicans, including Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterococcus faecalis, Staphylococcus aureus, Salmonella spp., Helicobacter pylori, Lactobacillus spp., Bacteroides spp., Clostridium difficile, and Streptococcus spp.

RESULTS

Most of the studied bacteria demonstrated both synergistic and antagonistic effects with C. albicans, and just a few bacteria such as P. aeruginosa, Salmonella spp., and Lactobacillus spp. demonstrated only antagonism against C. albicans.

CONCLUSIONS

Based on the nature of interactions reported so far by the literature between gut bacteria and C. albicans, it is expected to provide new ideas for the prevention and treatment of invasive intestinal candidiasis.

How Long Will It Take to Launch an Effective Helicobacter pylori Vaccine for Humans?

Helicobacter pylori infection often occurs in early childhood, and can last a lifetime if not treated with medication. H. pylori infection can also cause a variety of stomach diseases, which can only be treated with a combination of antibiotics. Combinations of antibiotics can cure H. pylori infection, but it is easy to relapse and develop drug resistance. Therefore, a vaccine is a promising strategy for prevention and therapy for the infection of H. pylori. After decades of research and development, there has been no appearance of any H. pylori vaccine reaching the market, unfortunately. This review summarizes the aspects of candidate antigens, immunoadjuvants, and delivery systems in the long journey of H. pylori vaccine research, and also introduces some clinical trials that have displayed encouraging or depressing results. Possible reasons for the inability of an H. pylori vaccine to be available over the counter are cautiously discussed and some propositions for the future of H. pylori vaccines are outlined.

Outer Membrane Vesicles (OMVs) as Biomedical Tools and Their Relevance as Immune-Modulating Agents against H. pylori Infections: Current Status and Future Prospects

Outer membrane vesicles (OMVs) are lipid-membrane-bounded nanoparticles that are released from Gram-negative bacteria via vesiculation of the outer membrane. They have vital roles in different biological processes and recently, they have received increasing attention as possible candidates for a broad variety of biomedical applications. In particular, OMVs have several characteristics that enable them to be promising candidates for immune modulation against pathogens, such as their ability to induce the host immune responses given their resemblance to the parental bacterial cell. Helicobacter pylori (H. pylori) is a common Gram-negative bacterium that infects half of the world's population and causes several gastrointestinal diseases such as peptic ulcer, gastritis, gastric lymphoma, and gastric carcinoma. The current H. pylori treatment/prevention regimens are poorly effective and have limited success. This review explores the current status and future prospects of OMVs in biomedicine with a special focus on their use as a potential candidate in immune modulation against H. pylori and its associated diseases. The emerging strategies that can be used to design OMVs as viable immunogenic candidates are discussed.

States and hotspots in Helicobacter pylori research from 2002 to 2021: A bibliometric analysis

BACKGROUND

Recently, numerous publications on Helicobacter pylori (H. pylori) have been published, but bibliometric analyses on this research field are scarce. To address this gap, we conducted a bibliometric analysis to provide a comprehensive overview and to explore the current research states and hotspots in this field.

MATERIALS AND METHODS

Publications on H. pylori from 2002 to 2021 were retrieved from the Web of Science Core Collection database (WoSCC). Trends in publications and citations were analyzed using Excel 2021. VOSviewer and Citespace were used to perform bibliometrics analysis.

RESULTS

36,266 publications on H. pylori were retrieved from the WoSCC database. In general, we observed an increasing trend in the number of publications over the past 20 years. The United States was the most productive and influential country, with the largest proportion of both publications and total citations. Helicobacter, US Department of Veterans Affairs, and Graham, David were the most productive journals, institutions and authors, respectively. Further analysis the co-occurrence and burst detection of keywords revealed that the most common keywords were "Helicobacter pylori," "gastric cancer," and "gastritis," all keywords were divided into eight main clusters, and the most important current research hotspot was the relationship between H. pylori infection and the changes of gut microbiota.

CONCLUSIONS

The United States has been the most productive and influential country on H. pylori research, and H. pylori-related research remains an active research field. The relationship between H. pylori infection and the changes of gut microbiota is a research hotspot attracting significant attention.

The Role of Adhesion in Helicobacter pylori Persistent Colonization

Helicobacter pylori (H. pylori) has coevolved with its human host for more than 100 000 years. It can safely colonize around the epithelium of gastric glands via their specific microstructures and proteins. Unless patients receive eradication treatment, H. pylori infection is always lifelong. However, few studies have discussed the reasons. This review will focus on the adhesion of H. pylori from the oral cavity to gastric mucosa and summarize the possible binding and translocation characteristics. Adhesion is the first step for persistent colonization after the directional motility, and factors related to adhesion are necessary. Outer membrane proteins, such as the blood group antigen binding adhesin (BabA) and the sialic acid binding adhesin (SabA), play pivotal roles in binding to human mucins and cellular surfaces. And this may offer different perspectives on eradication.

Trends and Complication Rates in Ulcerative Colitis Patients With and Without Helicobacter pylori Infections

Background Previous studies have shown an inverse relationship between ulcerative colitis (UC) and Helicobacter pylori infections (HPI). Though these two conditions have opposite geographic distributions, there may also be a physiological explanation for the decreased incidence of H. pylori infections in patients with UC. The purpose of this study is to analyze trends and complication rates of ulcerative colitis patients with and without HPI. Materials and methods The National Inpatient Sample (NIS) database was queried for patients with a primary diagnosis of UC, stratified by the presence of H. pylori infection. Patient demographics, length of stay, total hospital charges, and mortality were compared by H. pylori status. Additionally, complication rates were also compared between the two groups. Chi-squared and independent t-tests were used to compare outcomes and demographics, and multiple logistic regression was used to analyze primary and secondary outcomes. Results Patients with UC and HPI had a lower mortality rate (8.22 vs. 3.48, P<0.05, adjusted odds ratio [AOR] 0.33) and lower hospital charges ($65,652 vs. $47,557, p<0.05, AOR 1) with similar length of stay. Patients with UC and HPI also had lower rates of intestinal perforation (2.16% vs. 1.12%, p=0.05, AOR 0.408) and intrabdominal abscess formation (0.89% vs. 0.12%, AOR 0.165, p=0.072), though this difference was not significant. From 2001 to 2013, the incidence of UC has increased while the incidence of HPI has decreased. Conclusions The lower hospital charges and mortality rate as well as decreased rates of intestinal perforation and abscess formation suggest that there may be a physiologic role that HPI plays in modulating UC. Further studies into the interaction of these two conditions would be beneficial in clarifying their relationship and may help guide treatment of UC.

An overview of the structure and function of the flagellar hook FlgE protein

The flagellum is an important organelle for the survival of bacteria and consists of a basal body, hook, and filament. The FlgE protein is the subunit of the hook that connects the basal body and the filament and determines the motility of bacteria. Also, flgE gene plays an essential role in flagellar biosynthesis, swimming ability and biofilm formation. Although the intact flagella and the major component filament have been extensively studied, so far, little is known about the comprehensive understanding of flagellar hook and FlgE. Here in this review, we summarize the structures of flagellar hook and its subunit FlgE in various species and physiological functions of FlgE, including the hook assembly, the structural characteristics of flagellar hook, the mechanical properties of hook, and the similarities and differences between FlgE (hook) and FlgG (distal rod), with special attention on the interaction of FlgE with other molecules, the antigenicity and pro-inflammatory effect of FlgE, and cross-linking of FlgE in spirochetes. We hope our summary of this review could provide a better understanding of the FlgE protein and provide some useful information for developing new effective antibacterial drugs in the future work.

Motility of Different Gastric Helicobacter spp

Helicobacter spp., including the well-known human gastric pathogen H. pylori, can cause gastric diseases in humans and other mammals. They are Gram-negative bacteria that colonize the gastric epithelium and use their multiple flagella to move across the protective gastric mucus layer. The flagella of different Helicobacter spp. vary in their location and number. This review focuses on the swimming characteristics of different species with different flagellar architectures and cell shapes. All Helicobacter spp. use a run-reverse-reorient mechanism to swim in aqueous solutions, as well as in gastric mucin. Comparisons of different strains and mutants of H. pylori varying in cell shape and the number of flagella show that their swimming speed increases with an increasing number of flagella and is somewhat enhanced with a helical cell body shape. The swimming mechanism of H. suis, which has bipolar flagella, is more complex than that of unipolar H. pylori. H. suis exhibits multiple modes of flagellar orientation while swimming. The pH-dependent viscosity and gelation of gastric mucin significantly impact the motility of Helicobacter spp. In the absence of urea, these bacteria do not swim in mucin gel at pH < 4, even though their flagellar bundle rotates.

Targeted Computed Tomography Visualization and Healing of Inflammatory Bowel Disease by Orally Delivered Bacterial-Flagella-Inspired Polydiiododiacetylene Nanofibers

Accurate diagnosis and timely therapeutic intervention of inflammatory bowel disease (IBD) is essential in preventing the progression of the disease, although it still represents an insurmountable challenge. Here we report the design of bacterial-flagella-inspired polydiiododiacetylene (PIDA) nanofibers and its performance in targeted computed tomography (CT) imaging and on-demand therapeutic intervention of IBD. With a morphology mimicking bacterial flagella, PIDA nanofibers attach on the mucus layer of the gastrointestinal (GI) tract after oral administration, evenly distributing on the GI surface to portray the GI lining under CT scan within 2 h. PIDA can retain for a longer time in the damaged mucosa at the inflamed lesions than in normal GI tissues to enable the targeted CT visualization of IBD. PIDA also scavenges reactive oxygen species and ameliorates gut dysbiosis attributed to its iodine-substituted polydiacetylene structure, so that the enriched PIDA nanofibers at the targeted IBD lesions can alleviate the inflammation while maintaining the gut microbiota homeostasis, thus promoting the rebalance of GI microenvironment and the mucosal healing.

Assembly of novel microbial genomes from gut metagenomes of rhesus macaque (Macaca mulatta)

Rhesus macaque (RM, Macaca mulatta), as an important model animal, commonly suffers from chronic diarrheal disease, challenging the breeding of RMs. Gut microbiomes play key roles in maintaining intestinal health of RMs. However, it is still unclear about more features of gut microbiome as responsible for intestinal health of RMs. In this study, we performed de novo assembly of metagenome-assembled genomes (MAGs) based on fecal metagenomes from chronic diarrheal RMs and asymptomatic individuals. In total of 731 non-redundant MAGs with at least 80% completeness were reconstructed in this study. More than 97% MAGs were novel genomes compared with more than 250,000 reference genomes. MAGs of Campylobacter and Helicobacteraceae from RM guts mainly carried flagella-associated virulence genes and chemotaxis-associated virulence genes, which might mediate motility and adhesion of bacteria. Comparing to MAGs of Campylobacter from humans, distributions and functions of these MAGs of Campylobacter from RMs exhibited significant differences. Most members of Bacteroidota, Spirochaetota, Helicobacteraceae, Lactobacillaceae and Anaerovibrio significantly decreased in guts of chronic diarrhea RMs. More than 92% MAGs in this study were not contained in 2,985 MAGs previously reported from other 22 non-human primates (NHPs), expanding the microbial diversity in guts of NHPs. The distributions and functions of gut microbiome were prominently influenced by host phylogeny of NHPs. Our results could help to more clearly understand about the diversity and function of RMs gut microbiome.

Pathogenomics of Helicobacter pylori

The human stomach bacterium Helicobacter pylori, the causative agent of gastritis, ulcers and adenocarcinoma, possesses very high genetic diversity. H. pylori has been associated with anatomically modern humans since their origins over 100,000 years ago and has co-evolved with its human host ever since. Predominantly intrafamilial and local transmission, along with genetic isolation, genetic drift, and selection have facilitated the development of distinct bacterial populations that are characteristic for large geographical areas. H. pylori utilizes a large arsenal of virulence and colonization factors to mediate the interaction with its host. Those include various adhesins, the vacuolating cytotoxin VacA, urease, serine protease HtrA, the cytotoxin-associated genes pathogenicity island (cagPAI)-encoded type-IV secretion system and its effector protein CagA, all of which contribute to disease development. While many pathogenicity-related factors are present in all strains, some belong to the auxiliary genome and are associated with specific phylogeographic populations. H. pylori is naturally competent for DNA uptake and recombination, and its genome evolution is driven by extraordinarily high recombination and mutation rates that are by far exceeding those in other bacteria. Comparative genome analyses revealed that adaptation of H. pylori to individual hosts is associated with strong selection for particular protein variants that facilitate immune evasion, especially in surface-exposed and in secreted virulence factors. Recent studies identified single-nucleotide polymorphisms (SNPs) in H. pylori that are associated with the development of severe gastric disease, including gastric cancer. Here, we review the current knowledge about the pathogenomics of H. pylori.

Perspectives from recent advances of Helicobacter pylori vaccines research

BACKGROUND

Helicobacter pylori (H. pylori) infection is the main factor leading to some gastric diseases. Currently, H. pylori infection is primarily treated with antibiotics. However, with the widespread application of antibiotics, H. pylori resistance to antibiotics has also gradually increased year by year. Vaccines may be an alternative solution to clear H. pylori.

AIMS

By reviewing the recent progress on H. pylori vaccines, we expected it to lead to more research efforts to accelerate breakthroughs in this field.

MATERIALS & METHODS

We searched the research on H. pylori vaccine in recent years through PubMed®, and then classified and summarized these studies.

RESULTS

The study of the pathogenic mechanism of H. pylori has led to the development of vaccines using some antigens, such as urease, catalase, and heat shock protein (Hsp). Based on these antigens, whole-cell, subunit, nucleic acid, vector, and H. pylori exosome vaccines have been tested.

DISCUSSION

At present, researchers have developed many types of vaccines, such as whole cell vaccines, subunit vaccines, vector vaccines, etc. However, although some of these vaccines induced protective immunity in mouse models, only a few were able to move into human trials. We propose that mRNA vaccine may play an important role in preventing or treating H. pylori infection. The current study shows that we have developed various types of vaccines based on the virulence factors of H. pylori. However, only a few vaccines have entered human clinical trials. In order to improve the efficacy of vaccines, it is necessary to enhance T-cell immunity.

CONCLUSION

We should fully understand the pathogenic mechanism of H. pylori and find its core antigen as a vaccine target.

1α, 25-Dihydroxyvitamin D3 protects gastric mucosa epithelial cells against Helicobacter pylori-infected apoptosis through a vitamin D receptor-dependent c-Raf/MEK/ERK pathway

CONTEXT

Due to the resistance of Helicobacter pylori to antibiotics, it is difficult to eradicate this pathogenic bacterium from the host. The role of 1α, 25-dihydroxyvitamin D3 (1,25-D3) in H. pylori-infected gastric mucosa epithelial cells remains unknown.

OBJECTIVE

This study investigates the protective property of 1,25-D3 against H. pylori-infected apoptosis in gastric mucosa epithelial cells and its potential molecular mechanisms.

MATERIALS AND METHODS

GES-1 cells were infected with H. pylori SS1 strain (MOI: 100) and treated with 1,25-D3 at 100, 200, and 300 nM for 24 h. Mice were orally gavaged with 10⁸ CFUs of H. pylori and 25 µg/kg 1,25-D3 every other day for 1 month. CCK-8, LDH assay, TUNEL assay and western blot were used to determine the effect of 1,25-D3 on H. pylori-induced apoptosis.

RESULTS

H. pylori infection decreased cell viability to 59.2%, while 100-300 nM 1,25-D3 increased cell viability to 62.2%, 78.4% and 87.1%, respectively. Compared with positive control (4.53-fold), 1,25-D3 reduced caspase-3 activity to 4.49-, 2.88- and 1.49-fold, reduced caspase-6 activity to 2.36-, 1.88- and 1.50-fold, reduced caspase-9 activity to 4.55-, 2.91- and 2.01-fold. 1,25-D3 alters Bcl-2 family, caspase protein expression and c-Raf/MEK/ERK phosphorylation levels in vivo and in vitro. Suppression of 1,25-D3 in apoptosis was reliant on binding to vitamin D receptor. The pharmacological inhibition of c-Raf/MEK/ERK phosphorylation blocked the anti-apoptotic effect of 1,25-D3.

DISCUSSION AND CONCLUSION

1,25-D3 protected gastric mucosa epithelial cells against H. pylori-infected apoptosis through a VDR-dependent c-Raf/MEK/ERK pathway.

Histopathological Features of Helicobacter pylori Infection in Gastric Mucosa

Objective

To investigate the histopathological characteristics of Helicobacter pylori (Hp) infection in the gastric mucosa in the process from occurrence to intraepithelial neoplasia.

Methods

Specimens obtained from the endoscopic biopsy and endoscopic submucosal dissection of 2457 cases of gastric Hp infection were observed and assessed in detail using histology and immunohistochemistry techniques. The condition was divided according to the histopathological characteristics of gastric mucosal damage caused by Hp infection. The histopathological characteristics and immunophenotype of each stage were subsequently elucidated.

Results

Helicobacter pylori is initially implanted in the mucus layer covered by the epithelium on the surface of the gastric mucosa. It then selectively adheres to the cytoplasm of the surface mucus cells, which makes the oval and spherical particles containing mucus that is wrapped by the bounded membrane in the cytoplasm on the nucleus of the surface mucus cells disappear, while the cytoplasm undergoes spiderweb-like vacuolar degeneration. This leads to the proliferation and transformation of the surface mucous cells before developing into intraepithelial neoplasia. In the process of histomorphology, mucosal ulcers, mucosal lymphoid tissue proliferation, gland atrophy, intestinal epithelial metaplasia, mucosa-associated lymphoid tissue lymphoma, and adenocarcinoma may occur. In this study, the condition was divided into five stages according to the histopathological characteristics of gastric mucosal damage caused by Hp infection, as well as the degree of gastric mucosal damage and involvement depth as follows: the mucus infection stage, the surface epithelial cell infection stage, the lamina propria lesion stage, the mucosal atrophy stage, and the intraepithelial neoplasia stage.

Conclusion

Understanding the histopathological characteristics of gastric Hp infection in terms of its occurrence and development into intraepithelial neoplasia is conducive to the precise treatment and tracking of malignant cell transformation, and is of great significance in controlling the occurrence and development of gastric cancer.

Brazilian Red Propolis Presents Promising Anti-H. pylori Activity in In Vitro and In Vivo Assays with the Ability to Modulate the Immune Response

Helicobacter pylori is a Gram-negative, microaerophilic, curved-rod, flagellated bacterium commonly found in the stomach mucosa and associated with different gastrointestinal diseases. With high levels of prevalence worldwide, it has developed resistance to the antibiotics used in its therapy. Brazilian red propolis has been studied due to its biological properties, and in the literature, it has shown promising antibacterial activities. The aim of this study was to evaluate anti-H. pylori from the crude hydroalcoholic extract of Brazilian red propolis (CHEBRP). For this, in vitro determination of the minimum inhibitory and bactericidal concentration (MIC/MBC) and synergistic activity and in vivo, microbiological, and histopathological analyses using Wistar rats were carried out using CHEBRP against H. pylori strains (ATCC 46523 and clinical isolate). CHEBRP presented MIC/MBC of 50 and 100 μg/mL against H. pylori strains (ATCC 43526 and clinical isolate, respectively) and tetracycline MIC/MBC of 0.74 µg/mL. The association of CHEBRP with tetracycline had an indifferent effect. In the stomach mucosa of rats, all treatments performed significantly decreased the number of H. pylori, and a concentration of 300 mg/kg was able to modulate the inflammatory response in the tissue. Therefore, CHEBRP showed promising anti-H. pylori in in vitro and in vivo assays.

Gastric cancer in a patient with chronic gastritis after <i>H. pylori</i> eradication: assessing the risks

Stomach cancer occupies a leading position in oncological morbidity and mortality worldwide. Approximately 800,000 people die from stomach cancer every year. In two-thirds of patients gastric cancer is diagnosed at a late stage, when radical treatment becomes impossible. Helicobacter pylori (H. pylori) infection is considered as the main etiological factor for gastric cancer. To stratify the risk of developing gastric cancer an assessment of morphological changes in the gastric mucosa using the Operative Link for Gastritis Assessment of Atrophic Gastritis (OLGA) system is used. The stage of gastritis plays a key role in determining an individual’s risk of developing stomach cancer. H. pylori eradication therapy is an effective method for preventing gastric cancer. However not in all patients the elimination of the infection can prevent the development of gastric cancer in the future. It is extremely important to identify a group of people with ex-helicobacter gastritis, who have a high risk of developing stomach cancer, and to take timely preventive measures in them. The purpose of this publication is to summarize and systematize the currently available data on the risk of developing gastric cancer in patients with H. pylori-associated gastritis, including those after successful eradication.

Incorporating Immunotherapy in the Management of Gastric Cancer: Molecular and Clinical Implications

Simple Summary

Gastric cancer is one of the most common malignant tumours worldwide, with the fifth and third highest morbidity and mortality, respectively, of all cancers. Survival is limited, as most of the patients are diagnosed at an advanced stage, and are not suitable for surgery with a curative intent. Chemotherapy has only modestly improved patients’ outcomes and is mainly given with a palliative intent. Immunotherapy has improved overall survival of patients with gastric cancer, and has thus become a new standard of care in clinic. In this review we discuss the strong molecular rationale for the administration of immunotherapy in this disease and analyse the clinical data supporting its use.

Abstract

Gastric cancer has a median survival of 11 months, and this poor prognosis has not improved over the last 30 years. Recent pre-clinical data suggest that there is high tumour-related neoantigen expression in gastric cancer cells, suggesting that a clinical strategy that enhances the host’s immune system against cancer cells may be a successful approach to improve clinical outcomes. Additionally, there has been an increasing amount of translational evidence highlighting the relevance of PD-L1 expression in gastric cancer cells, indicating that PD-1/PD-L1 inhibitors may be useful. Several molecular subgroups of gastric cancer have been identified to respond with excellent outcomes to immunotherapy, including microsatellite instable tumours, tumours bearing a high tumour mutational burden, and tumours related to a chronic EBV infection. In gastric cancer, immunotherapy has produced durable responses in chemo-refractory patients; however, most recently there has been a lot of enthusiasm as several large-scale clinical trials highlight the improved survival noted from the incorporation of immunotherapy in the first line setting for advanced gastric cancer. Our review aims to discuss current pre-clinical and clinical data supporting the innovative role of immunotherapy in gastric cancer.

Stomach Cancer Screening Services of Bhutan

Stomach cancer is a common public health problem in South East Asia including Bhutan. Chronic infection with Helicobacter pylori is regarded as the principal cause of stomach cancer. Herein, we present the incidence of stomach cancer in Bhutan for eight years (from 2014 to 2021). We also discuss the steps taken for the prevention and early detection of stomach cancer.

How Does Helicobacter pylori Infection Cause Gastric Mucosal Atrophy

Objective

To investigate the occurrence and development of gastric mucosal atrophy due to Helicobacter pylori (Hp) infection and the accompanying histomorphological features.

Methods

Detailed histological observations and immunohistochemical examinations were conducted via 197 endoscopic biopsies and endoscopic submucosal dissection specimens of gastric mucosal atrophic lesions with gastric Hp infection. Detailed observation was made of columnar cells in the proliferative region of the deep gastric pit and the isthmus of the gastric gland, as well as the upper part of the glandular cervix.

Results

The infection of the gastric mucosa by Hp firstly led to the proliferative disorder of stem cells in the normal proliferative region of the gastric mucosa. This caused substantial propagation of cells in the proliferative region of the deep gastric pit and the isthmus of the gastric gland, as well as the upper part of the glandular cervix, as a means to replenish the damaged surface mucus cells. However, the propagation of stem cells in the proliferative region was insufficient for downward migration, and the normal physiological process of differentiation into fundic/pyloric gland cells was disrupted, resulting in glandular atrophy of the intrinsic layer of the gastric mucosa. Persistent Hp infection and disruption of stem cell proliferation in the proliferative region subsequently resulted in extensive segmental hyperplasia of the gastric mucosa and glandular atrophy of the lamina propria.

Conclusion

The occurrence, development, and histomorphological features of gastric mucosal atrophy due to gastric Hp infection provide a reliable pathological basis for precise treatment by clinicians and are of great significance for controlling the development of gastric cancer.

Flagellotropic Bacteriophages: Opportunities and Challenges for Antimicrobial Applications

Bacteriophages (phages) are the most abundant biological entities in the biosphere. As viruses that solely infect bacteria, phages have myriad healthcare and agricultural applications including phage therapy and antibacterial treatments in the foodservice industry. Phage therapy has been explored since the turn of the twentieth century but was no longer prioritized following the invention of antibiotics. As we approach a post-antibiotic society, phage therapy research has experienced a significant resurgence for the use of phages against antibiotic-resistant bacteria, a growing concern in modern medicine. Phages are extraordinarily diverse, as are their host receptor targets. Flagellotropic (flagellum-dependent) phages begin their infection cycle by attaching to the flagellum of their motile host, although the later stages of the infection process of most of these phages remain elusive. Flagella are helical appendages required for swimming and swarming motility and are also of great importance for virulence in many pathogenic bacteria of clinical relevance. Not only is bacterial motility itself frequently important for virulence, as it allows pathogenic bacteria to move toward their host and find nutrients more effectively, but flagella can also serve additional functions including mediating bacterial adhesion to surfaces. Flagella are also a potent antigen recognized by the human immune system. Phages utilizing the flagellum for infections are of particular interest due to the unique evolutionary tradeoff they force upon their hosts: by downregulating or abolishing motility to escape infection by a flagellotropic phage, a pathogenic bacterium would also likely attenuate its virulence. This factor may lead to flagellotropic phages becoming especially potent antibacterial agents. This review outlines past, present, and future research of flagellotropic phages, including their molecular mechanisms of infection and potential future applications.

Scope and Limitations of Current Antibiotic Therapies against Helicobacter pylori: Reviewing Amoxicillin Gastroretentive Formulations

Even though general improvement of quality of life has happened around the globe, statistics show that gastric cancer is still a very serious medical concern in some regions of the world. A big portion of malignant neoplasms that develop inside the stomach are linked to an infection of Helicobacter pylori; in fact, this pathogen has already been categorized as a group 1 carcinogen by the World Health Organization (WHO). Still, the efficacy of current anti-H. pylori therapeutic approaches is insufficient and follows a worrying decreasing trend, mainly due to an exponential increase in resistance to key antibiotics. This work analyzes the clinical and biological characteristics of this pathogen, especially its link to gastric cancer, and provides a comprehensive review of current formulation trends for H. pylori eradication. Research effort has focused both on the discovery of new combinations of chemicals that function as optimized antibiotic regimens, and on the preparation of gastroretentive drug delivery systems (GRDDSs) to improve overall pharmacokinetics. Regarding the last topic, this review aims to summarize the latest trend in amoxicillin-loaded GRDDS, since this is the antibiotic that has shown the least bacterial resistance worldwide. It is expected that the current work could provide some insight into the importance of innovative options to combat this microorganism. Therefore, this review can inspire new research strategies in the development of efficient formulations for the treatment of this infection and the consequent prevention of gastric cancer.

Inflammation and Gastric Cancer

Gastric cancer remains a major killer globally, although its incidence has declined over the past century. It is the fifth most common cancer and the third most common reason for cancer-related deaths worldwide. Gastric cancer is the outcome of a complex interaction between environmental, host genetic, and microbial factors. There is significant evidence supporting the association between chronic inflammation and the onset of cancer. This association is particularly robust for gastrointestinal cancers in which microbial pathogens are responsible for the chronic inflammation that can be a triggering factor for the onset of those cancers. Helicobacter pylori is the most prominent example since it is the most widespread infection, affecting nearly half of the world’s population. It is well-known to be responsible for inducing chronic gastric inflammation progressing to atrophy, metaplasia, dysplasia, and eventually, gastric cancer. This review provides an overview of the association of the factors playing a role in chronic inflammation; the bacterial characteristics which are responsible for the colonization, persistence in the stomach, and triggering of inflammation; the microbiome involved in the chronic inflammation process; and the host factors that have a role in determining whether gastritis progresses to gastric cancer. Understanding these interconnections may improve our ability to prevent gastric cancer development and enhance our understanding of existing cases.

Biomarker Characterization and Prediction of Virulence and Antibiotic Resistance from Helicobacter pylori Next Generation Sequencing Data

The Gram-negative bacterium Helicobacter pylori colonizes c.a. 50% of human stomachs worldwide and is the major risk factor for gastric adenocarcinoma. Its high genetic variability makes it difficult to identify biomarkers of early stages of infection that can reliably predict its outcome. Moreover, the increasing antibiotic resistance found in H. pylori defies therapy, constituting a major human health problem. Here, we review H. pylori virulence factors and genes involved in antibiotic resistance, as well as the technologies currently used for their detection. Furthermore, we show that next generation sequencing may lead to faster characterization of virulence factors and prediction of the antibiotic resistance profile, thus contributing to personalized treatment and management of H. pylori-associated infections. With this new approach, more and permanent data will be generated at a lower cost, opening the future to new applications for H. pylori biomarker identification and antibiotic resistance prediction.

Influence of Helicobacter pylori infection on PD-1/PD-L1 blockade therapy needs more attention

BACKGROUND AND OBJECTIVE

The tumor microenvironment and tumor immunity are crucially involved in tumor therapy. Immune checkpoint inhibitors targeting PD-1/PD-L1 signal transduction have been widely used in tumor therapy and have shown ideal clinical efficacy. However, some kinds of cancers still do not respond to PD-1/PD-L1 blockade therapy effectively, including gastric cancer. The related factors should be explored.

METHODS AND RESULTS

This review summarizes the recent progression of understanding the influence of Helicobacter pylori infection on PD-1/PD-L1 blockade therapy. Current pieces of evidence have indicated that H. pylori infection might affect the curative effect of tumor therapy associating with the induced immunomodulation.

CONCLUSION

It is necessary to understand the overall integration of PD-1/PD-L1 blockade therapy, the tumor microenvironment, and H. pylori infection. Much attention on the influence of H. pylori infection on the efficacy of tumor immunotherapy should be paid.

AI-2 Induces Urease Expression Through Downregulation of Orphan Response Regulator HP1021 in Helicobacter pylori

Helicobacter pylori causes gastric infections in more than half of the world's population. The bacterium's survival in the stomach is mediated by the abundant production of urease to enable acid acclimation. In this study, our transcriptomic analysis demonstrated that the expression of urease structural proteins, UreA and UreB, is induced by the autoinducer AI-2 in H. pylori. We also found that the orphan response regulator HP1021 is downregulated by AI-2, resulting in the induction of urease expression. HP1021 represses the expression of urease by directly binding to the promoter region of ureAB, ranging from −47 to +3 with respect to the transcriptional start site. The study findings suggest that quorum sensing via AI-2 enhances acid acclimation when bacterial density increases, and might enable bacterial dispersal to other sites when entering gastric acid.