Mouse Models for Assessing the Protective Efficacy of Lactobacillus gasseri SBT2055 against Helicobacter suis Infection Associated with the Development of Gastric Mucosa-Associated Lymphoid Tissue Lymphoma

Molecular Mechanisms and Treatment Strategies for Helicobacter pylori-Induced Gastric Carcinogenesis and Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma

Helicobacter pylori has been classified as a class I carcinogen by WHO because of its primary involvement in the development of gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma. This review focuses on understanding the molecular pathophysiological mechanisms that operate within intracellular transduction pathways and their relevance in the treatment strategies for the two main diseases caused by H. pylori. H. pylori virulence factors such as cytotoxin-associated gene A and vacuolating cytotoxin A genotypes, inflammatory mediators, H. pylori-induced microRNA deregulation, alterations in autophagy proteins and regulators, and changes in DNA methylation are some of the molecular mechanisms that play essential roles in H. pylori infection and gastric carcinogenesis. The discovery of novel treatment strategies that target the deregulated intracellular transduction pathways in gastric carcinogenesis and MALT lymphoma is critical. H. pylori eradication (HPE) is not limited to H. pylori-dependent low-grade MALT lymphoma and may be used in patients with high-grade diffuse large B-cell lymphoma (DLBCL) (de novo or DLBCL-MALT lymphoma). The loss of H. pylori dependency and high-grade transformation appear to be distinct events in the progression of gastric lymphoma. Interestingly, patients with H. pylori-positive gastric DLBCL without histological evidence of MALT lymphoma (pure gastric DLBCL) may respond to HPE therapy.

The role of Helicobacter suis, Fusobacterium gastrosuis, and the pars oesophageal microbiota in gastric ulceration in slaughter pigs receiving meal or pelleted feed

This study investigated the role of causative infectious agents in ulceration of the non-glandular part of the porcine stomach (pars oesophagea). In total, 150 stomachs from slaughter pigs were included, 75 from pigs that received a meal feed, 75 from pigs that received an equivalent pelleted feed with a smaller particle size. The pars oesophagea was macroscopically examined after slaughter. (q)PCR assays for H. suis, F. gastrosuis and H. pylori-like organisms were performed, as well as 16S rRNA sequencing for pars oesophagea microbiome analyses. All 150 pig stomachs showed lesions. F. gastrosuis was detected in 115 cases (77%) and H. suis in 117 cases (78%), with 92 cases (61%) of co-infection; H. pylori-like organisms were detected in one case. Higher infectious loads of H. suis increased the odds of severe gastric lesions (OR = 1.14, p = 0.038), while the presence of H. suis infection in the pyloric gland zone increased the probability of pars oesophageal erosions [16.4% (95% CI 0.6-32.2%)]. The causal effect of H. suis was mediated by decreased pars oesophageal microbiome diversity [-1.9% (95% CI - 5.0-1.2%)], increased abundances of Veillonella and Campylobacter spp., and decreased abundances of Lactobacillus, Escherichia-Shigella, and Enterobacteriaceae spp. Higher infectious loads of F. gastrosuis in the pars oesophagea decreased the odds of severe gastric lesions (OR = 0.8, p = 0.0014). Feed pelleting had no significant impact on the prevalence of severe gastric lesions (OR = 1.72, p = 0.28). H. suis infections are a risk factor for ulceration of the porcine pars oesophagea, probably mediated through alterations in pars oesophageal microbiome diversity and composition.

Evaluation of the Potential Protective Effects of Lactobacillus Strains against Helicobacter pylori Infection: A Randomized, Double-Blinded, Placebo-Controlled Trial

BACKGROUND

The beneficial effects of probiotic supplementation standard antibiotic therapies for Helicobacter pylori infection have been verified, but the ability of probiotic monotherapy to eradicate H. pylori remains unclear.

AIM

To evaluate the accuracy and efficacy of specific Lactobacillus strains against H. pylori infection.

METHODS

Seventy-eight patients with H. pylori infection were treated with strain L. crispatus G14-5M (L. crispatus CCFM1118) or L. helveticus M2-09-R02-S146 (L. helveticus CCFM1121) or L. plantarum CCFM8610 at a dose of 2 g twice daily for one month. ¹⁴C-urea breath test, the gastrointestinal symptom rating scale, serum pepsinogen concentrations, and serum cytokine concentrations of patients were measured at baseline and end-of-trial to analyze the effect of the Lactobacillus strains in eradicating H. pylori infection and reducing gastrointestinal discomfort in patients. In addition, the composition and abundance of the intestinal microbiota of patients were also measured at end-of-trial.

RESULTS

The ¹⁴C-urea breath test value of the three Lactobacillus treatment groups had decreased significantly, and the eradication rate of H. pylori had increased by the end of the trial. In particular, the eradication rate in the G14-5M treatment group was significantly higher than the placebo group (70.59% vs. 15.38%, P=0.0039), indicating that one-month administration of the G14-5M regimen was sufficient to eradicate H. pylori infection. The ingestion of Lactobacillus strains also ameliorated the gastrointestinal symptom rating scale scores, and the serum interleukin-8 concentrations of H. pylori-infected patients appeared to modulate the gut microbiota of patients. However, none of the Lactobacillus strains had a significant effect on general blood physiological characteristics, serum tumor necrosis factor α concentrations, or serum pepsinogen concentrations in the patients.

CONCLUSION

Three Lactobacillus strains significantly alleviate the gastrointestinal discomfort and the gastric inflammatory response of H. pylori-infected patients. The activity of probiotics in eradicating H. pyloriinfection may be species/strain specific.

Gastric Helicobacter species associated with dogs, cats and pigs: significance for public and animal health

This article focuses on the pathogenic significance of Helicobacter species naturally colonizing the stomach of dogs, cats and pigs. These gastric "non-Helicobacter (H.) pylori Helicobacter species" (NHPH) are less well-known than the human adapted H. pylori. Helicobacter suis has been associated with gastritis and decreased daily weight gain in pigs. Several studies also attribute a role to this pathogen in the development of hyperkeratosis and ulceration of the non-glandular stratified squamous epithelium of the pars oesophagea of the porcine stomach. The stomach of dogs and cats can be colonized by several Helicobacter species but their pathogenic significance for these animals is probably low. Helicobacter suis as well as several canine and feline gastric Helicobacter species may also infect humans, resulting in gastritis, peptic and duodenal ulcers, and low-grade mucosa-associated lymphoid tissue lymphoma. These agents may be transmitted to humans most likely through direct or indirect contact with dogs, cats and pigs. Additional possible transmission routes include consumption of water and, for H. suis, also consumption of contaminated pork. It has been described that standard H. pylori eradication therapy is usually also effective to eradicate the NHPH in human patients, although acquired antimicrobial resistance may occasionally occur and porcine H. suis strains are intrinsically less susceptible to aminopenicillins than non-human primate H. suis strains and other gastric Helicobacter species. Virulence factors of H. suis and the canine and feline gastric Helicobacter species include urease activity, motility, chemotaxis, adhesins and gamma-glutamyl transpeptidase. These NHPH, however, lack orthologs of cytotoxin-associated gene pathogenicity island and vacuolating cytotoxin A, which are major virulence factors in H. pylori. It can be concluded that besides H. pylori, gastric Helicobacter species associated with dogs, cats and pigs are also clinically relevant in humans. Although recent research has provided better insights regarding pathogenic mechanisms and treatment strategies, a lot remains to be investigated, including true prevalence rates, exact modes of transmission and molecular pathways underlying disease development and progression.

Probiotics as the live microscopic fighters against Helicobacter pylori gastric infections

Background

Helicobacter pylori (H. pylori) is the causative agent of stomach diseases such as duodenal ulcer and gastric cancer, in this regard incomplete eradication of this bacterium has become to a serious concern. Probiotics are a group of the beneficial bacteria which increase the cure rate of H. pylori infections through various mechanisms such as competitive inhibition, co-aggregation ability, enhancing mucus production, production of bacteriocins, and modulating immune response.

Result

In this study, according to the received articles, the anti-H. pylori activities of probiotics were reviewed. Based on studies, administration of standard antibiotic therapy combined with probiotics plays an important role in the effective treatment of H. pylori infection. According to the literature, Lactobacillus casei, Lactobacillus reuteri, Lactobacillus rhamnosus GG, and Saccharomyces boulardii can effectively eradicate H. pylori infection. Our results showed that in addition to decrease gastrointestinal symptoms, probiotics can reduce the side effects of antibiotics (especially diarrhea) by altering the intestinal microbiome.

Conclusion

Nevertheless, antagonist activities of probiotics are H. pylori strain-specific. In general, these bacteria can be used for therapeutic purposes such as adjuvant therapy, drug-delivery system, as well as enhancing immune system against H. pylori infection.

Potential utility of nano-based treatment approaches to address the risk of Helicobacter pylori

INTRODUCTION

Helicobacter pylori (H. pylori) has occupied a significant place among infectious pathogens and it has been documented as a leading challenge due to its higher resistance to the commonly used drugs, higher adaptability, and lower targeting specificity of the available drugs.

AREAS COVERED

New treatment strategies are urgently needed in order to improve the current advancement in modern medicine. Nanocarriers have gained an advantage of drug encapsulation and high retention time in the stomach with a prolonged drug release rate at the targeted site. This article aims to highlight the recent advances in nanotechnology with special emphasis on metallic, polymeric, lipid, membrane coated, and target-specific nanoparticles (NPs), as well as, natural products for treating H. pylori infection. We discussed a comprehensive approach to understand H. pylori infection and elicits to rethink about the increasing threat posed by H. pylori and its treatment strategies.

EXPERT OPINION

To address these issues, nanotechnology has got huge potential to combat H. pylori infection and has made great progress in the field of biomedicine. Moreover, combinatory studies of natural products and probiotics in conjugation with NPs have proven efficiency against H. pylori infection, with an advantage of lower cytotoxicity, minimal side effects, and stronger antibacterial potential.[Figure: see text].

Human Gut Microbiota-associated Gastrointestinal Malignancies: A Comprehensive Review

The human gastrointestinal tract houses trillions of microbes. The gut and various types of microorganisms, including bacteria, viruses, fungi, and archaea, form a complex ecosystem known as the gut microbiota, and the whole genome of the gut microbiota is referred to as the gut microbiome. The gut microbiota is essential for homeostasis and the overall well-being of a person and is increasingly considered an adjunct "virtual organ," with a complexity level comparable to that of the other organ systems. The gut microbiota plays an essential role in nutrition, local mucosal homeostasis, inflammation, and the mucosal immune system. An imbalanced state of the gut microbiota, known as dysbiosis, can predispose to development of various gastrointestinal malignancies through three speculated pathogenic mechanisms: (a) direct cytotoxic effects with damage to the host DNA, (b) disproportionate proinflammatory signaling inducing inflammation, and (c) activation of tumorigenic pathways or suppression of tumor-suppressing pathways. Several microorganisms, including Helicobacter pylori, Epstein-Barr virus, human papillomavirus, Mycoplasma species, Escherichia coli, and Streptococcus bovis, are associated with gastrointestinal malignancies such as esophageal adenocarcinoma, gastric adenocarcinoma, gastric mucosa-associated lymphoid tissue lymphoma, colorectal adenocarcinoma, and anal squamous cell carcinoma. Imaging plays a pivotal role in diagnosis and management of microbiota-associated gastrointestinal malignancies. Appropriate use of probiotics, fecal microbiota transplantation, and overall promotion of the healthy gut are ongoing areas of research for prevention and treatment of malignancies. Online supplemental material is available for this article. ^©RSNA, 2021.

Isolation and characterization of Helicobacter suis from human stomach

Helicobacter suis, a bacterial species naturally hosted by pigs, can colonize the human stomach in the context of gastric diseases such as gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Because H. suis has been successfully isolated from pigs, but not from humans, evidence linking human H. suis infection to gastric diseases has remained incomplete. In this study, we successfully in vitro cultured H. suis directly from human stomachs. Unlike Helicobacter pylori, the viability of H. suis decreases significantly on neutral pH; therefore, we achieved this using a low-pH medium for transport of gastric biopsies. Ultimately, we isolated H. suis from three patients with gastric diseases, including gastric MALT lymphoma. Successful eradication of H. suis yielded significant improvements in endoscopic and histopathological findings. Oral infection of mice with H. suis clinical isolates elicited gastric and systemic inflammatory responses; in addition, progression of gastric mucosal metaplasia was observed 4 mo postinfection. Because H. suis could be isolated from the stomachs of infected mice, our findings satisfied Koch's postulates. Although further prospective clinical studies are needed, H. suis, like H. pylori, is likely a gastric pathogen in humans. Furthermore, comparative genomic analysis of H. suis using complete genomes of clinical isolates revealed that the genome of each H. suis isolate contained highly plastic genomic regions encoding putative strain-specific virulence factors, including type IV secretion system-associated genes, and that H. suis isolates from humans and pigs were genetically very similar, suggesting possible pig-to-human transmission.

Synergistic effect of Lactobacillus gasseri and Cudrania tricuspidata on the modulation of body weight and gut microbiota structure in diet-induced obese mice

High-fat diet (HFD)-induced obesity has been associated with alteration of gut microbiota alongside body weight gain. In this study, the synbiotic effect of Lactobacillus gasseri 505 (LG) and Cudrania tricuspidata (CT) in HFD-induced mice was revealed. After feeding mice with high-fat diet for 10 weeks, combination of LG and CT (LG_CT) exhibited the greatest reduction in the final body weight (11.9%). Moreover, microbial diversity significantly increased, and Principal Coordinate Analysis (PCoA) revealed that the LG_CT group showed closer cluster to NORM. At phylum level, the Firmicutes/Bacteroidetes (F/B) ratio increased in HFD, and the abundance of Bacteroidetes was restored by LG and CT. At genus level, notable changes in Alistipes, Desulfovibrio, Bilophila, and Acetatifactor were observed. Helicobacter elevated to 16.2% in HFD and diminished dramatically to less than 0.01% in LG and/or CT. At species level, L. gasseri increased after the administration of LG (0.54%) and LG_CT (1.14%), suggesting that LG may grow and colonize in the gut and CT can function as a prebiotic. Finally, functional analysis revealed certain metabolic factors correlated with body weight and gut microbiota. This study serves as a potential basis for the application of L. gasseri 505 and C. tricuspidata in the prevention and treatment of diet-induced obesity.Key Points • Combination of L. gasseri (LG) and C. tricuspidata (CT) reduced body weight gain.• Microbial diversity significantly increased in LG_CT treatment.• Abundance of microorganisms involved with leanness increased in LG, CT, and LG_CT.• Body weight is associated with some metabolic functions of gut microbiota.

Protective efficacy of a hydroxy fatty acid against gastric Helicobacter infections

BACKGROUND

We have previously revealed that omega-3 polyunsaturated fatty acids can prevent Helicobacter pylori infection by blocking the futalosine pathway, an alternative route for menaquinone (MK) biosynthesis.

MATERIALS AND METHODS

1, Different H. pylori strains were grown in liquid media supplemented with linoleic acid, an omega-6 fatty acid, or its 10-hydroxy derivative, 10-hydroxy-cis-12-octadecenoic acid (HYA), in the presence or absence of MK. The bacterial numbers in the media were estimated by plating; 2, C57BL/6NCrl mice received drinking water supplemented with different fatty acids starting from 1 week before infection with H. pylori or Helicobacter suis until the end of the experiment. The gastric colonization levels of H. pylori or H. suis were determined 2 weeks after infection by plating or quantitative PCR, respectively; 3, Mice were given HYA, starting 1 week before infection with H. suis and continuing until 6 months after infection, for analysis of the gastric conditions.

RESULTS

1, A low concentration (20 μmol/L) of HYA in culture broth suppressed the growth of H. pylori, and this inhibition was reduced by MK supplementation; 2, HYA treatment protected mice against H. pylori or H. suis infection; 3, HYA treatment suppressed the formation of lymphoid follicles in the gastric mucus layer after H. suis infection.

CONCLUSIONS

HYA prevents gastric Helicobacter infections by blocking their futalosine pathways. Daily HYA supplementation is effective for the prevention of gastric mucosa-associated lymphoid tissue lymphoma induced by persistent infection with H. suis.

Development of the gut microbiota in infancy and its impact on health in later life

Gut microbial ecology and function are dynamic in infancy, but are stabilized in childhood. The 'new friends' have a great impact on the development of the digestive tract and host immune system. In the first year of life, especially, the gut microbiota dramatically changes through interactions with the developing immune system in the gut. The process of establishing the gut microbiota is affected by various environmental factors, with the potential to be a main determinant of life-long health. In this review, we summarize recent findings regarding gut microbiota establishment, including the importance of various factors related to the development of the immune system and allergic diseases later in life.

Adhesion Properties of Lactic Acid Bacteria on Intestinal Mucin

Lactic acid bacteria (LAB) are Gram-positive bacteria that are natural inhabitants of the gastrointestinal (GI) tracts of mammals, including humans. Since Mechnikov first proposed that yogurt could prevent intestinal putrefaction and aging, the beneficial effects of LAB have been widely demonstrated. The region between the duodenum and the terminal of the ileum is the primary region colonized by LAB, particularly the Lactobacillus species, and this region is covered by a mucus layer composed mainly of mucin-type glycoproteins. The mucus layer plays a role in protecting the intestinal epithelial cells against damage, but is also considered to be critical for the adhesion of Lactobacillus in the GI tract. Consequently, the adhesion exhibited by lactobacilli on mucin has attracted attention as one of the critical factors contributing to the persistent beneficial effects of Lactobacillus in a constantly changing intestinal environment. Thus, understanding the interactions between Lactobacillus and mucin is crucial for elucidating the survival strategies of LAB in the GI tract. This review highlights the properties of the interactions between Lactobacillus and mucin, while concomitantly considering the structure of the GI tract from a histochemical perspective.

Draft Genome Sequence of Helicobacter suis Strain SNTW101, Isolated from a Japanese Patient with Nodular Gastritis

We present here the draft whole-genome shotgun sequence of an uncultivated strain SNTW101 of Helicobacter suis, which has been maintained in the stomachs of mice. This strain was originally isolated from gastric biopsy specimens of a urea breath test-negative Japanese patient suffering from nodular gastritis.

In vitro investigation of molecules involved in Lactobacillus gasseri SBT2055 adhesion to host intestinal tract components

AIMS

The adhesion ability of Lactobacillus gasseri SBT2055 was investigated in vitro by searching for its adhesion molecules.

METHODS AND RESULTS

Lactobacillus gasseri SBT2055 showed adherence to host components, including two commercially available mucins, Caco-2 epithelial-like cells and the extracellular matrix molecule fibronectin (Fn). Its adhesion rates to host components were generally higher than those of other Lactobacillus strains. We examined sortase-dependent proteins (SDPs) anchored by a sortase enzyme encoded by srtA1. The adhesion rates of an srtA1 disruptant were lower than those of Lact. gasseri SBT2055, and the relative adherences were as follows: two mucins, 43 and 40%; Caco-2, 66% and Fn, 28%. Seven additional gene disruptants were generated to determine the precise SDPs that contribute to adhesion to each component.

CONCLUSIONS

The adhesion ability of Lact. gasseri SBT2055 was superior to those of other Lactobacillus strains. Additionally, four adhesion molecules were newly identified from candidate SDPs.

SIGNIFICANCE AND IMPACT OF THE STUDY

Although the contribution of SDPs to adhesion has been reported using sortase gene disruptants, this is the first report to identify the precise SDPs that act as adhesion molecules. Our results will contribute to achieving better understanding of probiotic bacterial adherence.

Lactobacillus rhamnosus GG SpaC pilin subunit binds to the carbohydrate moieties of intestinal glycoconjugates

Lactobacillus rhamnosus GG (LGG) is a well-established probiotic strain. The beneficial properties of this strain are partially dependent on its prolonged residence in the gastrointestinal tract, and are likely influenced by its adhesion to the intestinal mucosa. The pilin SpaC subunit, located within the Spa pili structure, is the most well studied LGG adhesion factor. However, the binding epitopes of SpaC remain largely unknown. The aim of this study was to evaluate the binding properties of SpaC to the carbohydrate moieties of intestinal glycoconjugates using a recombinant SpaC protein. In a competitive enzyme-linked immunosorbent assay, SpaC binding was markedly reduced by addition of purified mucin and the mucin oligosaccharide fraction. Histochemical staining revealed that the binding of SpaC was drastically reduced by periodic acid treatment. Moreover, in the surface plasmon resonance-based Biacore assay, SpaC bound strongly to the carbohydrate moieties containing β-galactoside at the non-reducing terminus of glycolipids. We here provide the first demonstration that SpaC binds to the oligosaccharide chains of mucins, and that the carbohydrate moieties containing β-galactoside at the non-reducing termini of glycoconjugates play a crucial role in this binding. Our results demonstrate the importance of carbohydrates of SpaC for mucus interactions.

The Other Helicobacters

In the past year, a substantial number of (putative) novel Helicobacter species have been described, including Helicobacter himalayensis colonizing the Himalayan marmot and Helicobacter apodemus, colonizing the Korean striped field mouse. In addition, a putative novel gastric Helicobacter species was identified in wild gorillas and chimpanzees, for which the name "Candidatus H. homininae" was proposed. A high incidence of gastric non-H. pylori Helicobacter infection was described in China and multiple case reports have described the involvement of enterohepatic Helicobacter species, especially Helicobacter cinaedi, in a wide range of diseases. Several studies in rodent models further elucidated the mechanisms underlying the development of gastric mucosa-associated lymphoid tissue lymphoma during infection with gastric non-H. pylori Helicobacters. The effects of infection with gastric Helicobacters on the development of neuroinflammation were investigated and several enterohepatic Helicobacter species were shown to affect the composition of the gut microbiota, to influence vaccine efficiency as well as the progression of cancer in distant sites of the body.