Non-pylori Helicobacters (NHPHs) Induce Shifts in Gastric Microbiota in Helicobacter pylori-Infected Patients

Modified Gexia-Zhuyu Tang inhibits gastric cancer progression by restoring gut microbiota and regulating pyroptosis

BACKGROUND

Gexia-Zhuyu Tang (GZT), a traditional Chinese medicine formula, is used to treat a variety of diseases. However, its roles in gastric cancer (GC) remain unclear.

OBJECTIVE

The aim of this study was to explore the roles and underlying molecular mechanisms of modified GZT in GC.

METHODS

The effects of modified GZT on GC were investigated by constructing mouse xenograft models with MFC cell line. The fecal samples from low-dose, high-dose, and without modified GZT treatment groups were collected for the 16S rRNA gene sequencing and fecal microbiota transplantation (FMT). Histopathological alterations of mice were evaluated using the hematoxylin-eosin (HE). Immunohistochemical (IHC) analysis with Ki67 and GSDMD was performed to measure tissue cell proliferation and pyroptosis, respectively. Proteins associated with pyroptosis, invasion, and metastasis were detected by Western blotting. Enzyme-linked immunosorbent assay (ELISA) was used to assess inflammation-related factors levels.

RESULTS

Modified GZT inhibited GC tumor growth and reduced metastasis and invasion-related proteins expression levels, including CD147, VEGF, and MMP-9. Furthermore, it notably promoted caspase-1-dependent pyroptosis, as evidenced by a dose-dependent increase in TNF-α, IL-1β, IL-18, and LDH levels, along with elevated protein expression of NLRP3, ASC, and caspase-1. Additionally, modified GZT increased species abundance and diversity of the intestinal flora. FMT assay identified that modified GZT inhibited GC tumor progression through regulation of intestinal flora.

CONCLUSIONS

Modified GZT treatment may promote pyroptosis by modulating gut microbiota in GC. This study identifies a new potential approach for the GC clinical treatment.

Helicobacter pylori and gastric microbiota homeostasis: progress and prospects

Helicobacter pylori, a Gram-negative microaerobic bacteria belonging to the phylum Proteobacteria, can colonize in the stomach and duodenum, and cause a series of gastrointestinal diseases such as gastritis, gastric ulcer and even gastric cancer. At present, the high diversity of the microorganisms in the stomach has been confirmed with culture-independent methods; some researchers have also studied the stomach microbiota composition at different stages of H. pylori carcinogenesis. Here, we mainly review the possible role of H. pylori-mediated microbiota changes in the occurrence and development of gastric cancer to provide new ideas for preventing H. pylori infection and regulating microecological imbalance.

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.

The Effects of Helicobacter pylori Infection on Gastric Microbiota in Children With Duodenal Ulcer

Background

Helicobacter pylori (H. pylori) infection is the main cause of chronic gastritis and duodenal ulcer in children. Little is known about the effect of H. pylori on gastric microbiota in children with duodenal ulcer. This study is aimed at the characteristics of gastric microbiota in children with duodenal ulcer on H. pylori infection.

Methods

We studied 23 children diagnosed with duodenal ulcer by gastric endoscopy because of the gastrointestinal symptoms, 15 children were diagnosed with H. pylori infection, while 8 children were without H. pylori infection. Endoscopic mucosal biopsy samples were obtained for DNA extraction. Microbiomes were analyzed by 16S rRNA profiling and microbial functions were predicted using the software Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt).

Results

Bacterial richness and diversity of gastric microbiota in duodenal ulcer with H. pylori-positive were lower than those negative. The gastric microbiota in H. pylori-positive group significantly reduced proportions of six phyla and fifteen genera; only Helicobacter taxa were more abundant in H. pylori-positive group. Co-expression network analysis showed a more complex network of interactions in the H. pylori-positive group than that in the H. pylori-negative group. For the predicted functions, lower abundance in the pathways of carbohydrate metabolism, signal transduction, amino acid metabolism, and lipid metabolism were found in H. pylori-positive group than the H. pylori-negative group. H. pylori colonization reduces a microbial community with genotoxic potential in the gastric mucosa of children with duodenal ulcer.

Conclusions

The presence of H. pylori significantly influences gastric microbiota and results in a lower abundance of multiple taxonomic levels in children with duodenal ulcer. Children with duodenal ulcer exhibit a dysbiotic microbial community with genotoxic potential, which is distinct from that of children with H. pylori infection.

Clinical Trial Registration

[http://www.chictr.org.cn], identifier [ChiCTR1800015190].

Dysbiotic change in gastric microbiome and its functional implication in gastric carcinogenesis

Although there is a growing interest in the role of gastric microbiome on the development of gastric cancer, the exact mechanism is largely unknown. We aimed to investigate the changes of gastric microbiome during gastric carcinogenesis, and to predict the functional potentials of the microbiome involved in the cancer development. The gastric microbiome was analyzed using gastric juice samples from 88 prospectively enrolled patients, who were classified into gastritis, gastric adenoma, or early/advanced gastric cancer group. Differences in microbial diversity and composition were analyzed with 16S rRNA gene profiling, using next-generation sequencing method. Metagenomic biomarkers were selected using logistic regression models, based on relative abundances at genus level. We used Tax4Fun to predict possible functional pathways of gastric microbiome involved in the carcinogenesis. The microbial diversity continuously decreased in its sequential process of gastric carcinogenesis, from gastritis to gastric cancer. The microbial composition was significantly different among the four groups of each disease status, as well as between the cancer group and non-cancer group. Gastritis group was differently enriched with genera Akkermansia and Lachnospiraceae NK4A136 Group, whereas the cancer group was enriched with Lactobacillus and Veillonella. Predictive analysis of the functional capacity of the microbiome suggested enrichment or depletion of several functional pathways related to carcinogenesis in the cancer group. There are significant changes in the diversity and composition of gastric microbiome during the gastric carcinogenesis process. Gastric cancer was characterized with microbial dysbiosis, along with functional changes potentially favoring carcinogenesis.

A comprehensive update: gastrointestinal microflora, gastric cancer and gastric premalignant condition, and intervention by traditional Chinese medicine

With the recent upsurge of studies in the field of microbiology, we have learned more about the complexity of the gastrointestinal microecosystem. More than 30 genera and 1000 species of gastrointestinal microflora have been found. The structure of the normal microflora is relatively stable, and is in an interdependent and restricted dynamic equilibrium with the body. In recent years, studies have shown that there is a potential relationship between gastrointestinal microflora imbalance and gastric cancer (GC) and precancerous lesions. So, restoring the balance of gastrointestinal microflora is of great significance. Moreover, intervention in gastric premalignant condition (GPC), also known as precancerous lesion of gastric cancer (PLGC), has been the focus of current clinical studies. The holistic view of traditional Chinese medicine (TCM) is consistent with the microecology concept, and oral TCM can play a two-way regulatory role directly with the microflora in the digestive tract, restoring the homeostasis of gastrointestinal microflora to prevent canceration. However, large gaps in knowledge remain to be addressed. This review aims to provide new ideas and a reference for clinical practice.

Effects of Helicobacter pylori Infection on the Oral Microbiota of Reflux Esophagitis Patients

The human oral microbiota plays a vital role in maintaining metabolic homeostasis. To explore the relationship between Helicobacter pylori (Hp) and reflux esophagitis, we collected 86 saliva samples from reflux esophagitis patients (RE group) and 106 saliva samples from healthy people (C group) for a high-throughput sequencing comparison. No difference in alpha diversity was detected between the RE and the C groups, but beta diversity of the RE group was higher than the C group. Bacteroidetes was more abundant in the RE group, whereas Firmicutes was more abundant in the C group. The linear discriminant analysis effect size analysis demonstrated that the biomarkers of the RE group were Prevotella, Veillonella, Leptotrichia, and Actinomyces, and the biomarkers of the C group were Lautropia, Gemella, Rothia, and Streptococcus. The oral microbial network structure of the C group was more complex than that of the RE group. Second, to explore the effect of Hp on the oral microbiota of RE patients, we performed the ¹⁴C-urea breath test on 45 of the 86 RE patients. We compared the oral microbiota of 33 Hp-infected reflux esophagitis patients (REHpp group) and 12 non-Hp-infected reflux esophagitis patients (REHpn group). No difference in alpha diversity was observed between the REHpn and REHpp groups, and beta diversity of the REHpp group was significantly lower than that of the REHpn group. The biomarkers in the REHpp group were Veillonella, Haemophilus, Selenomonas, Megasphaera, Oribacterium, Butyrivibrio, and Campylobacter; and the biomarker in the REHpn group was Stomatobaculum. Megasphaera was positively correlated with Veillonella in the microbial network of the REHpp group. The main finding of this study is that RE disturbs the human oral microbiota, such as increased beta diversity. Hp infection may inhibit this disorderly trend.

A report of nonexistence of the non-Helicobacter pylori Helicobacter species in Iranian patients suffering from inflammatory bowel disease

Inflammatory bowel disease is a chronic, relapsing-remitting gastrointestinal disorder which has become a serious global concern, and it imposes a great degree of health and economic burdens on communities worldwide. Although the presence of non-Helicobacter pylori Helicobacter (NHPH) microorganisms has been reported in various gastrointestinal disorders, their putative role in the pathogenesis of IBD has been a matter of controversy. The present study aimed to investigate the existence of gastric and enterohepatic NHPHs and their probable coinfection with H. pylori in IBD. Totally, 168 clinical specimens including 70 colonic biopsies and 98 fecal specimens were obtained from IBD patients. Genomic DNA was extracted from all samples, and its quality and concentration were assessed by β-globin PCR and spectrophotometry. The Helicobacter genus-specific PCR was performed using 16S rRNA gene. All samples were also tested for H. pylori infection by PCR of ureC gene fragment (glmM). The presence of NHPH was examined by using species-specific PCR assays. Based on PCR results, H. pylori was detected in 12.9% and 3.1% of colonic biopsies and fecal specimens, respectively. However, no statistically significant correlation was observed (P value > 0.05). We failed to find NHPH in both colonic biopsies and fecal specimens from IBD patients. Despite the fact that none of the IBD patients harbored the NHPH in the current work, further cohorts with larger sample size are required to determine the possible relationship between NHPH infection and IBD pathogenesis.

Changes in Gastric Corpus Microbiota With Age and After Helicobacter pylori Eradication: A Long-Term Follow-Up Study

Helicobacter pylori infection changes gastric microbiota profiles. However, it is not clear whether H. pylori eradication can restore the healthy gastric microbiota. Moreover, there has been no study regarding the changes in gastric microbiota with aging. The objective of this study was to investigate the changes in gastric corpus microbiota with age and following H. pylori eradication. Changes in corpus mucosa-associated microbiota were evaluated in 43 individuals with endoscopic follow-up > 1 year, including 8 H. pylori-uninfected and 15 H. pylori-infected subjects with no atrophy/metaplasia by histology and pepsinogen I/II ratio > 4.0; 17 H. pylori-infected subjects with atrophy/metaplasia and pepsinogen I/II ratio < 2.5; and 3 subjects with atrophy/metaplasia, no evidence of active H. pylori infection, negative for anti-H. pylori immunoglobulin G (IgG) antibody testing, and no previous history of H. pylori eradication. Successful H. pylori eradication was achieved in 21 patients. The gastric microbiota was characterized using an Illumina MiSeq platform targeting 16S ribosomal DNA (rDNA). The mean follow-up duration was 57.4 months (range, 12-145 months), and median follow-up visit was 1 (range, 1-3). Relative abundance of Lactobacillales and Streptococcus was increased with atrophy/metaplasia. In H. pylori-uninfected subjects (n = 8), an increase in Proteobacteria (Enhydrobacter, Comamonadaceae, Sphingobium); a decrease in Firmicutes (Streptococcus, Veillonella), Fusobacteria (Fusobacterium), Nocardioidaceae, Rothia, and Prevotella; and a decrease in microbial diversity were observed during the follow-up (p trend < 0.05). In 10 of 21 subjects (47.6%), H. pylori eradication induced restoration of microbial diversity; however, a predominance of Acinetobacter with a decrease in microbial diversity occurred in 11 subjects (52.3%). The presence of atrophy/metaplasia at baseline and higher neutrophil infiltration in the corpus were associated with the restoration of gastric microbiota after successful eradication, whereas a higher relative abundance of Acinetobacter at baseline was associated with the predominance of Acinetobacter after H. pylori eradication (p < 0.05). To conclude, in H. pylori-uninfected stomach, relative abundance of Proteobacteria increases, relative abundance of Firmicutes and Fusobacteria decreases, and microbial diversity decreases with aging. H. pylori eradication does not always restore gastric microbiota; in some individuals, gastric colonization by Acinetobacter species occurs after anti-Helicobacter treatment.

The relationship of gastric microbiota and Helicobacter pylori infection in pediatrics population

BACKGROUND

In recent years, the impact of Helicobacter pylori (H pylori) on the gut microbiota has attracted more attention; however, the relationship in pediatric population rarely was reported.

METHODS

Endoscopic gastric mucosal biopsy specimens from 55 children with gastrointestinal symptoms were collected, 37 of them were H pylori-positive (23 nonpeptic ulcer and 14 peptic ulcer) and 18 were H pylori-negative. In addition, 11 specimens were collected from H pylori-positive children who performed second endoscopy in 4 weeks after therapy. Microbial abundance and compositions were analyzed by 16S ribosomal RNA amplification and microbial functions were predicted using the software PICRUSt.

RESULTS

The gastric microbiota of H pylori-positive children were mainly dominated by Helicobacter in genus (95.43%). The microbiota richness and diversity of H pylori-positive children were lower than that of H pylori-negative children. No difference was found in microbiota structure between H pylori-positive children with or without peptic ulcer. The richness and compositions after therapy were closer to the characteristics of H pylori-negative children. For predicted functions, higher abundance in pathways of infection diseases, cancer and lower abundance in the pathways of amino acid, lipid, and carbohydrate metabolism were found in H pylori-positive group than H pylori-negative group.

CONCLUSION

The characteristics of gastric microbiota were affected by H pylori infection rather than disease states, and the richness and diversity of gastric species were inverse correlation with H pylori infection in children. Eradication therapy was helpful to restore shifted gastric microbiota.

Helicobacter suis infection alters glycosylation and decreases the pathogen growth inhibiting effect and binding avidity of gastric mucins

Helicobacter suis is the most prevalent non-Helicobacter pylori Helicobacter species in the human stomach and is associated with chronic gastritis, peptic ulcer disease, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. H. suis colonizes the gastric mucosa of 60-95% of pigs at slaughter age, and is associated with chronic gastritis, decreased weight gain, and ulcers. Here, we show that experimental H. suis infection changes the mucin composition and glycosylation, decreasing the amount of H. suis-binding glycan structures in the pig gastric mucus niche. Similarly, the H. suis-binding ability of mucins from H. pylori-infected humans is lower than that of noninfected individuals. Furthermore, the H. suis growth-inhibiting effect of mucins from both noninfected humans and pigs is replaced by a growth-enhancing effect by mucins from infected individuals/pigs. Thus, Helicobacter spp. infections impair the mucus barrier by decreasing the H. suis-binding ability of the mucins and by decreasing the antiprolific activity that mucins can have on H. suis. Inhibition of these mucus-based defenses creates a more stable and inhabitable niche for H. suis. This is likely of importance for long-term colonization and outcome of infection, and reversing these impairments may have therapeutic benefits.

Compositional and Functional Differences between Microbiota and Cervical Carcinogenesis as Identified by Shotgun Metagenomic Sequencing

Recent studies have reported the potential role of microbiomes in cervical disease. However, little is known about the microbiome composition and function in cervical carcinogenesis. We aimed to identify the compositional and functional alterations of cervical microbiomes in cases of cervical carcinogenesis of Korean women using shotgun metagenomic sequencing. In this study, using shotgun sequencing, we sequenced the cervical metagenomes of cervical intraneoplasia 2/3 (n = 17), cervical cancer (n = 12), and normal controls (n = 18) to identify the microbial abundances and enriched metabolic functions in cervical metagenomes. At the genus level, the microbiota of cervical cancer were differentially enriched with genera Alkaliphilus, Pseudothermotoga, and Wolbachia. Cervical intraepithelial neoplasia (CIN) 2/3 were enriched with Lactobacillus, Staphylococcus, and Candidatus Endolissoclinum. The normal group was enriched with Pseudoalteromonas and Psychrobacter. Further characterization of the functionalities of the metagenomes may suggest that six Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologies (KOs) that are involved in 10 pathways are associated with an increased risk of CIN2/3 and cervical cancer. Specifically, cervical metagenomes were enriched in the course of peptidoglycan synthesis and depleted by dioxin degradation and 4-oxalocrotonate tautomerase. The Cluster of Orthologous Groups (COG) category ‘Defense mechanisms’ was depleted in cervical cancer patients. Our findings based on shotgun metagenomic sequencing suggest that cervical microbiome community compositions and their metagenomics profiles differed between cervical lesions and normal subjects. Future studies should have larger sample sizes and/or aggregate their results to have sufficient power to detect reproducible and significant associations.

Other Helicobacters and the gastric microbiome

The current article is a review of the most important, accessible, and relevant literature published between April 2017 and March 2018 on other Helicobacters and the gastric microbiome. The first part of the review focuses on literature describing non-Helicobacter pylori-Helicobacter (NHPH) infections in humans and animals whilst the subsequent section focuses specifically on the human gastric microbiome. Novel diagnostic methods as well as new NHPHs species have been identified in recent studies. Furthermore, our knowledge about the pathogenesis of NHPH infections has been further enhanced by important fundamental studies in cell lines and animal models. Over the last year, additional insights over the prevalence and potential prevention strategies of NHPHs have also been reported. With regard to understanding the gastric microbiome, new information detailing the structure of the gastric microbiota at different stages of H. pylori infection, within different patient geographical locations, was documented. There was also a study detailing the impact of proton-pump inhibitor usage and the effect on the gastric microbiome. Newer analysis approaches including defining the active microbiome through analysis of RNA rather than DNA-based sequencing were also published allowing the first assessments of the functional capabilities of the gastric microbiome.