Gastric and duodenum microflora analysis after long-term Helicobacter pylori infection in Mongolian Gerbils

Comparison of three methods for generating the coccoid form of Helicobacter pylori and proteomic analysis

BACKGROUND

Helicobacter pylori changes from spiral to coccoid depending on the host state, environmental factors, and surrounding microbial communities. The coccoid form of H. pylori still maintains its complete cellular structure, retains virulence genes, and thus plays a role in pathogenicity. To understand the coccoid form, it is crucial to establish the in vitro generation of the coccoid H. pylori. Although some conditions have been studied for the generation of the coccoid form, few studies have compared these conditions for coccoid generation. Here, we generated coccoid forms via three methods and compared the differences in morphology, viability, culturability, and protein expression.

RESULTS

The coccoid H. pylori was generated in vitro via three methods: a starvation method, a method using amoxicillin, and a method using the culture supernatant of Streptococcus mitis. The morphology and viability of the cells were examined by fluorescence microscopy after staining with SYTO9 and propidium iodide. The culturability of H. pylori was examined by counting colony-forming units on chocolate agar plates. In the starvation group, no colonies formed after 7 days, but viable coccoids were continuously observed. In the amoxicillin-treated group, the culturability decreased rapidly after 12 h, and showed a viable but non culturable (VBNC) state after the third day. Most cells treated with S. mitis supernatant changed to coccoid forms after 7 days, but colonies were continuously formed, probably due to living spiral forms. We performed proteomics to analyse the differences in protein profiles between the spiral and coccoid forms and protein profiles among the coccoid forms generated by the three methods.

CONCLUSION

Amoxicillin treatment changed H. pylori to VBNC cells faster than starvation. Treatment with the S. mitis supernatant prolonged the culturability of H. pylori, suggesting that the S. mitis supernatant may contain substances that support spiral form maintenance. Proteomic analysis revealed that the expression of proteins differed between the spiral form and coccoid form of H. pylori, and this variation was observed among the coccoid forms produced via three different methods. The proteins in the coccoid forms produced by the three methods differed from each other, but common proteins were also observed among them.

Exploring the Link between Helicobacter pylori, Gastric Microbiota and Gastric Cancer

Gastric cancer (GC) still represents one of the leading causes of cancer-related mortality and is a major public health issue worldwide. Understanding the etiopathogenetic mechanisms behind GC development holds immense potential to revolutionize patients' treatment and prognosis. Within the complex web of genetic predispositions and environmental factors, the connection between Helicobacter pylori (H. pylori) and gastric microbiota emerges as a focus of intense research investigation. According to the most recent hypotheses, H. pylori triggers inflammatory responses and molecular alterations in gastric mucosa, while non-Helicobacter microbiota modulates disease progression. In this review, we analyze the current state of the literature on the relationship between H. pylori and non-Helicobacter gastric microbiota in gastric carcinogenesis, highlighting the mechanisms by which microecological dysbiosis can contribute to the malignant transformation of the mucosa.

Current Knowledge about Gastric Microbiota with Special Emphasis on Helicobacter pylori-Related Gastric Conditions

The gastric milieu, because of its very low acidic pH, is very harsh for bacterial growth. The discovery of Helicobacter pylori (H.p.) has opened a new avenue for studies on the gastric microbiota, thus indicating that the stomach is not a sterile environment. Nowadays, new technologies of bacterial identification have demonstrated the existence of other microorganisms in the gastric habitat, which play an important role in health and disease. This bacterium possesses an arsenal of compounds which enable its survival but, at the same time, damage the gastric mucosa. Toxins, such as cytotoxin-associated gene A, vacuolar cytotoxin A, lipopolysaccharides, and adhesins, determine an inflammatory status of the gastric mucosa which may become chronic, ultimately leading to a gastric carcinoma. In the initial stage, H.p. persistence alters the gastric microbiota with a condition of dysbiosis, predisposing to inflammation. Probiotics and prebiotics exhibit beneficial effects on H.p. infection, and, among them, anti-inflammatory, antioxidant, and antibacterial activities are the major ones. Moreover, the association of probiotics with prebiotics (synbiotics) to conventional anti-H.p. therapy contributes to a more efficacious eradication of the bacterium. Also, polyphenols, largely present in the vegetal kingdom, have been demonstrated to alleviate H.p.-dependent pathologies, even including the inhibition of tumorigenesis. The gastric microbiota composition in health and disease is described. Then, cellular and molecular mechanisms of H.p.-mediated damage are clarified. Finally, the use of probiotics, prebiotics, and polyphenols in experimental models and in patients infected with H.p. is discussed.

Communal interaction of glycation and gut microbes in diabetes mellitus, Alzheimer's disease, and Parkinson's disease pathogenesis

Diabetes and its complications, Alzheimer's disease (AD), and Parkinson's disease (PD) are increasing gradually, reflecting a global threat vis-à-vis expressing the essentiality of a substantial paradigm shift in research and remedial actions. Protein glycation is influenced by several factors, like time, temperature, pH, metal ions, and the half-life of the protein. Surprisingly, most proteins associated with metabolic and neurodegenerative disorders are generally long-lived and hence susceptible to glycation. Remarkably, proteins linked with diabetes, AD, and PD share this characteristic. This modulates protein's structure, aggregation tendency, and toxicity, highlighting renovated attention. Gut microbes and microbial metabolites marked their importance in human health and diseases. Though many scientific shreds of evidence are proposed for possible change and dysbiosis in gut flora in these diseases, very little is known about the mechanisms. Screening and unfolding their functionality in metabolic and neurodegenerative disorders is essential in hunting the gut treasure. Therefore, it is imperative to evaluate the role of glycation as a common link in diabetes and neurodegenerative diseases, which helps to clarify if modulation of nonenzymatic glycation may act as a beneficial therapeutic strategy and gut microbes/metabolites may answer some of the crucial questions. This review briefly emphasizes the common functional attributes of glycation and gut microbes, the possible linkages, and discusses current treatment options and therapeutic challenges.

Gastric microbiota: an emerging player in gastric cancer

Gastric cancer (GC) is a common cancer worldwide with a high mortality rate. Many microbial factors influence GC, of which the most widely accepted one is Helicobacter pylori (H. pylori) infection. H. pylori causes inflammation, immune reactions and activation of multiple signaling pathways, leading to acid deficiency, epithelial atrophy, dysplasia and ultimately GC. It has been proved that complex microbial populations exist in the human stomach. H. pylori can affect the abundance and diversity of other bacteria. The interactions among gastric microbiota are collectively implicated in the onset of GC. Certain intervention strategies may regulate gastric homeostasis and mitigate gastric disorders. Probiotics, dietary fiber, and microbiota transplantation can potentially restore healthy microbiota. In this review, we elucidate the specific role of the gastric microbiota in GC and hope these data can facilitate the development of effective prevention and therapeutic approaches for GC.

Linking dysbiosis to precancerous stomach through inflammation: Deeper than and beyond imaging

Upper gastrointestinal endoscopy is considered the gold standard for gastric lesions detection and surveillance, but it is still associated with a non-negligible rate of missing conditions. In the Era of Personalized Medicine, biomarkers could be the key to overcome missed lesions or to better predict recurrence, pushing the frontier of endoscopy to functional endoscopy. In the last decade, microbiota in gastric cancer has been extensively explored, with gastric carcinogenesis being associated with progressive dysbiosis. Helicobacter pylori infection has been considered the main causative agent of gastritis due to its interference in disrupting the acidic environment of the stomach through inflammatory mediators. Thus, does inflammation bridge the gap between gastric dysbiosis and the gastric carcinogenesis cascade and could the microbiota-inflammation axis-derived biomarkers be the answer to the unmet challenge of functional upper endoscopy? To address this question, in this review, the available evidence on the role of gastric dysbiosis and chronic inflammation in precancerous conditions of the stomach is summarized, particularly targeting the nuclear factor-κB (NF-κB), toll-like receptors (TLRs) and cyclooxygenase-2 (COX-2) pathways. Additionally, the potential of liquid biopsies as a non-invasive source and the clinical utility of studied biomarkers is also explored. Overall, and although most studies offer a mechanistic perspective linking a strong proinflammatory Th1 cell response associated with, but not limited to, chronic infection with Helicobacter pylori, promising data recently published highlights not only the diagnostic value of microbial biomarkers but also the potential of gastric juice as a liquid biopsy pushing forward the concept of functional endoscopy and personalized care in gastric cancer early diagnosis and surveillance.

Clinical Pathogenesis, Molecular Mechanisms of Gastric Cancer Development

The human pathogen Helicobacter pylori is the strongest known risk factor for gastric disease and cancer, and gastric cancer remains a leading cause of cancer-related death across the globe. Carcinogenic mechanisms associated with H. pylori are multifactorial and are driven by bacterial virulence constituents, host immune responses, environmental factors such as iron and salt, and the microbiota. Infection with strains that harbor the cytotoxin-associated genes (cag) pathogenicity island, which encodes a type IV secretion system (T4SS) confer increased risk for developing more severe gastric diseases. Other important H. pylori virulence factors that augment disease progression include vacuolating cytotoxin A (VacA), specifically type s1m1 vacA alleles, serine protease HtrA, and the outer-membrane adhesins HopQ, BabA, SabA and OipA. Additional risk factors for gastric cancer include dietary factors such as diets that are high in salt or low in iron, H. pylori-induced perturbations of the gastric microbiome, host genetic polymorphisms, and infection with Epstein-Barr virus. This chapter discusses in detail host factors and how H. pylori virulence factors augment the risk of developing gastric cancer in human patients as well as how the Mongolian gerbil model has been used to define mechanisms of H. pylori-induced inflammation and cancer.

Helicobacter Pylori Infection Induces Intestinal Dysbiosis That Could Be Related to the Onset of Atherosclerosis

Cardiovascular diseases represent one of the first causes of death around the world, and atherosclerosis is one of the first steps in the development of them. Although these problems occur mainly in elderly, the incidence in younger people is being reported, and an undetermined portion of patients without the classic risk factors develop subclinical atherosclerosis at earlier stages of life. Recently, both the H. pylori infection and the intestinal microbiota have been linked to atherosclerosis. The mechanisms behind those associations are poorly understood, but some of the proposed explanations are (a) the effect of the chronic systemic inflammation induced by H. pylori, (b) a direct action over the endothelial cells by the cytotoxin associated gene A protein, and (c) alterations of the lipid metabolism and endothelial dysfunction induced by H. pylori infection. Regarding the microbiota, several studies show that induction of atherosclerosis is related to high levels of Trimethylamine N-oxide. In this review, we present the information published about the effects of H. pylori over the intestinal microbiota and their relationship with atherosclerosis and propose a hypothesis to explain the nature of these associations. If H. pylori contributes to atherosclerosis, then interventions for eradication and restoration of the gut microbiota at early stages could represent a way to prevent disease progression.

Saccharomyces cerevisiae I4 Showed Alleviating Effects on Dextran Sulfate Sodium-Induced Colitis of Balb/c Mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease. The purpose of this study was to investigate the ameliorating effects of three yeast strains, Saccharomyces cerevisiae I4, Clavispora lusitaniae 30 and Pichia kudriavzevii 11, isolated from traditional fermented dairy food in Xinjiang, China, on the ulcerative colitis symptoms of Balb/c mice treated by dextran sulfate sodium (DSS). Among which, S. cerevisiae I4 had good tolerance to simulated gastrointestinal juice and strong adhesion to HT–29 cells monolayers. Furthermore, the three yeast strains were oral administered to Balb/c mice with DSS induced colitis. The weight loss, colon shortening and histological injury of colitis mice were ameliorated. Then, oral administration of S. cerevisiae I4 improved the immune state by reducing the contents of TNF–α, IL–6 and IL–1β and increasing immunoglobulin. The relative expression of intestinal barrier proteins Claudin–1, Occludin and Zonula Occludins–1 (ZO–1) of the mice enhanced, and the short chain fatty acids (SCFAs) content such as Propionic acid, Butyric acid, Isobutyric acid and Isovaleric acid in the feces of the mice increased to varying degrees, after S. cerevisiae I4 treatment compared with the model group of drinking 3% DSS water without yeast treatment. Moreover, S. cerevisiae I4 treatment lifted the proportion of beneficial bacteria such as Muribaculaceae, Lactobacillaceae and Rikenellaceae in the intestinal tract of the mice, the abundance of harmful bacteria such as Staphylococcus aureus and Turicibacter was decreased. These results suggested that S. cerevisiae I4 could alleviate DSS induced colitis in mice by enhancing intestinal barrier function and regulating intestinal flora balance.

Effect of gastric microbiota on quadruple Helicobacter pylori eradication therapy containing bismuth

BACKGROUND

Helicobacter pylori (H. pylori) is an important pathogen that can cause a variety of diseases. Yet, full eradication of H. pylori remains a significant challenge in clinical practice. H. pylori and other microbial communities have complex interactions in the unique gastric microecological environment. However, it is not clear whether the interactions have any effect on the therapeutic effect of H. pylori.

AIM

The aim was to investigate the characteristics of the gastric microbiota with H. pylori infection and the influence on the H. pylori eradication treatment.

METHODS

Patients with H. pylori infection underwent gastroscopy and received treatment for eradication. The prescription included esomeprazole 20 mg bid, Livzon Dele 220 mg bid, amoxicillin 1000 mg bid, and clarithromycin 500 mg bid for 14 d. Patients who did not respond to treatment and failed eradication were compared with those who achieved eradication by 1:2 propensity matching. High-throughput sequencing of the gastric mucosal microbiota was performed, and the results were evaluated by alpha diversity analysis, beta diversity analysis, species correlation analysis, and metabolic pathway correlation analysis.

RESULTS

The eradication rate of all the patients was 95.5% (171/179). Twenty-four patients were enrolled in the study after propensity-matched scoring. There were eight cases in the failure group (patients who did not respond well to therapy) and 16 cases in the success group. The majority phyla in the two groups were the same, and included Proteobacteria, Bacteroides, Firmicutes, Actinomycetes, and Fusobacteria. The microbial diversity in the failure group had a decreasing trend (P = 0.092) and the species abundance was significantly lower (P = 0.031) compared with the success group. The high rate of H. pylori eradication was associated with Rhodococcus, Lactobacillus, and Sphingomonas, as they were significantly enriched in the successful group (P < 0.05). Veronococcus and Cilium were enriched in the mucosa of chronic atrophic gastritis patients compared with chronic superficial gastritis patients (P = 0.0466 and 0.0122, respectively). In both study groups, H. pylori was negatively correlated with other bacterial genera. More bacterial genera were directly related to H. pylori in the successful group compared with the failure group.

CONCLUSION

The effectiveness of quadruple H. pylori eradication therapy containing bismuth depended on gastric microbiota, and the high rate of H. pylori eradication was associated with the presence of Rhodococcus, Lactobacillus, and Sphingomonas.

Helicobacter pylori infection-induced changes in the intestinal microbiota of 14-year-old or 15-year-old Japanese adolescents: a cross-sectional study

OBJECTIVE

The relationship between Helicobacter pylori and the intestinal microbiota has not yet been clearly demonstrated in children and adolescents. The present study aimed at evaluating how H. pylori infection could affect the intestinal microbiota in adolescents using genetic analysis.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

We included subjects from a longitudinal project involving H. pylori screening and treatment of junior high school third-grade students (aged 14 or 15 years) in Saga Prefecture. The study included a control group (n=79) and an H. pylori group (n=80) tested negative and positive for the anti-H. pylori antibody in the urine and H. pylori antigen in stool specimens, respectively.

INTERVENTIONS

The intestinal microbiota was evaluated in stool specimens using 16S rRNA gene/DNA/amplicon sequencing with next-generation sequencing.

PRIMARY AND SECONDARY OUTCOME MEASURES

We assessed alpha and beta diversity, just as well as relative abundances within the bacterial composition at the genus level in both groups.

RESULTS

As shown by the alpha diversity of the 16S rRNA gene/DNA/amplicon sequence data, the control group exhibited lower microbial species richness with lower alpha diversity compared with the H. pylori group (p<0.001). The beta diversity of the intestinal microbiota profile also differed between the two groups (p<0.01). The relative abundance of the Prevotella genus was higher in the H. pylori group (p<0.01) concomitant with a gain in body mass index (BMI) in the H. pylori group (p<0.01) compared with the control group.

CONCLUSION

H. pylori infection significantly affected the intestinal microbiota in Japanese adolescents. In addition, the prevalence of the Prevotella genus is concomitantly increased along with the BMI in H. pylori-infected students.

TRIAL REGISTRATION NUMBER

UMIN000028721.

The impact of Helicobacter pylori infection on gut microbiota-endocrine system axis; modulation of metabolic hormone levels and energy homeostasis

The gut microbiota is a complex ecosystem that is involved in the development and preservation of the immune system, energy homeostasis and nutritional status of the host. The crosstalk between gut microbiota and the host cells modulates host physiology and metabolism through different mechanisms. Helicobacter pylori (H. pylori) is known to reside in the gastric mucosa, induce inflammation, and alter both gastric and intestinal microbiota resulting in a broad spectrum of diseases, in particular metabolic syndrome-related disorders. Infection with H. pylori have been shown to affect production level and physiological regulation of the gut metabolic hormones such as ghrelin and leptin which are involved in food intake, energy expenditure and body mass. In this study, we reviewed and discussed data from the literature and follow-up investigations that links H. pylori infection to alterations of the gut microbiota and metabolic hormone levels, which can exert broad influences on host metabolism, energy homeostasis, behavior, appetite, growth, reproduction and immunity. Also, we discussed the strong potential of fecal microbiota transplantation (FMT) as an innovative and promising investigational treatment option for homeostasis of metabolic hormone levels to overcome H. pylori-associated metabolic syndrome-related disorders.

Maternal H. pylori is associated with differential fecal microbiota in infants born by vaginal delivery

Helicobacter pylori colonization may affect the mucosal immune system through modification of microbiota composition and their interactions with the host. We hypothesized that maternal H. pylori status affects the maternal intestinal microbiota of both mother and newborn. In this study, we determine the structure of the fecal microbiota in mothers and neonates according to maternal H. pylori status and delivery mode. We included 22 mothers and H. pylori infection was determined by fecal antigen test. Eleven mothers (50%) were H. pylori-positive (7 delivering vaginally and 4 by C-section), and 11 were negative (6 delivering vaginally and 5 by C-section). Stool samples were obtained from mothers and infants and the fecal DNA was sequenced. The fecal microbiota from mothers and their babies differed by the maternal H. pylori status, only in vaginal birth, not in C-section delivery. All 22 infants tested negative for fecal H. pylori at 15 days of age, but those born vaginally -and not those by C-section- showed differences in the infant microbiota by maternal H. pylori status (PERMANOVA, p = 0.01), with higher abundance of Enterobacteriaceae and Veillonella, in those born to H. pylori-positive mothers. In conclusion, the structure of the infant fecal microbiota is affected by the maternal H. pylori status only in infants born vaginally, suggesting that the effect could be mediated by labor and birth exposures.

Mucosa microbiome of gastric lesions: Fungi and bacteria interactions

Many components of the gastric non-Helicobacter pylori microbiota have been identified recently thanks to advances in DNA sequencing techniques. Several lines of evidence support the hypothesis that the gastric microbiome is essential for gastric disorders such as gastric cancer. Microbial interactions impact the pathophysiology of various gastric disorders. This chapter provides an overview of recent findings regarding general gastric microbial community profiling, microbial interactions in the stomach, and microbial characteristics in various gastric disorders.

Gastric microflora and gastric disease

Gastric environment has long been considered sterile, but the discovery of Helicobacter pylori (H. pylori) changed such concept in 1982. Over the past few decades, modern techniques have provided insight into microbial communities in the stomach and the interactions between communities, ranging from methods that rely on bacterial culture to the application of macrogenomics and high-throughput sequencing techniques. H. pylori is an important risk factor for gastric disease, but there may be other bacteria involved in the occurrence of gastric disease. This review summarizes the current progress in the understanding of the relationship between gastric microflora and gastric disease.

A Novel View of Human Helicobacter pylori Infections: Interplay between Microbiota and Beta-Defensins

The gut microbiota is significantly involved in the preservation of the immune system of the host, protecting it against the pathogenic bacteria of the stomach. The correlation between gut microbiota and the host response supports human gastric homeostasis. Gut microbes may be shifted in Helicobacter pylori (Hp)-infected individuals to advance gastric inflammation and distinguished diseases. Particularly interesting is the establishment of cooperation between gut microbiota and antimicrobial peptides (AMPs) of the host in the gastrointestinal tract. AMPs have great importance in the innate immune reactions to Hp and participate in conservative co-evolution with an intricate microbiome. β-Defensins, a class of short, cationic, arginine-rich proteins belonging to the AMP group, are produced by epithelial and immunological cells. Their expression is enhanced during Hp infection. In this review, we discuss the impact of the gut microbiome on the host response, with particular regard to β-defensins in Hp-associated infections. In microbial infections, mostly in precancerous lesions induced by Hp infection, these modifications could lead to different outcomes.

Helicobacter pylori infection as a risk factor for serum bilirubin change and less favourable lipid profiles: a hospital-based health examination survey

Background

Helicobacter pylori infection is associated with several extragastric conditions including dyslipidemia and metabolic syndrome. This study aimed to investigate additional metabolic parameters associated with H. pylori infection in a Chinese population.

Methods

Using a case-control approach we studied 617 subjects with ¹³C-urea breath test (¹³C-UBT) values ≥10‰ who were defined as being positive for H. pylori (cases), while 617 sex and age- matched subjects with ¹³C-UBT values ≤1‰ were defined as H. pylori negative (controls) in Beijing Tongren Hospital from March 2016 to May 2017. Biochemical parameters including serum bilirubin and lipids were tested.

Results

A total of 1982 subjects participated in this study. The H. pylori infected subjects had significantly lower serum direct bilirubin concentrations (2.34 ± 0.38 vs. 2.47 ± 0.90 μmol/L, P = 0.008). H. pylori infection was independently associated with lower direct bilirubin levels (OR = 1.497, 95% CI =1.121–1.999, P = 0.006) or total bilirubin levels (OR = 1.322, 95% CI =1.005–1.738, P = 0.046) after adjustment for age, sex, body mass index (BMI), alanine aminotransferase (ALT), aspartate aminotransferase (AST), high-density lipoprotein cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), total cholesterol (TC) and triglycerides(TG). In addition, the H. pylori infected subjects had higher LDL-C levels (2.98 ± 0.76 vs. 2.89 ± 0.75 mmol/L, P = 0.033) and lower HDL-C levels (1.39 ± 0.37 vs. 1.44 ± 0.41 mmol/L, P = 0.044). LDL-C was negatively correlated with direct bilirubin concentration (R = − 0.260, P < 0.0001).

Conclusions

Bilirubin has been found to be a potent endogenous antioxidant and negatively associated with metabolic syndrome. Our results suggest that H. pylori infection is an independent risk factor for serum bilirubin reduction and less favorable lipid profiles.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3787-8) contains supplementary material, which is available to authorized users.

NAFLD, Helicobacter species and the intestinal microbiome

Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide. It is well-accepted that gut dysbiosis is associated with NAFLD, however, there is some conflicting evidence regarding the nature of these alterations. Infection with Helicobacter species, mainly H. pylori, has also been associated with increased NAFLD risk, however, some studies have failed to reproduce this finding. Further studies including large study samples and standardised procedures for microbiota analyses, H. pylori detection and NAFLD diagnostic criteria, are required. The mechanisms involving Helicobacter species and the intestinal microbiome in NAFLD pathogenesis appear to be part of the multiple-hit theory, in which increased intestinal permeability, inflammatory responses, altered choline, bile acids and carbohydrate metabolism, production of short-chain fatty acids, urea cycle and urea transport systems, altered maintenance of hepatic γδT-17 cells, insulin resistance, hormones secreted by the adipose tissue, metabolic hormones, bacterial metabolites and Helicobacter toxins, are all implicated.

Helicobacter pylori infection is associated with an increased risk of Parkinson's disease: A population-based retrospective cohort study

BACKGROUND

Several studies have evaluated the association of Parkinson's disease with Helicobacter pylori (HP) infection, although no cohort studies have evaluated this association among the general population.

OBJECTIVE

This study aimed to investigate the risk of Parkinson's disease after HP infection in the general Taiwanese population.

METHODS

This study of Taiwanese health insurance data (2000-2012) evaluated 9105 cases of HP infection and 9105 controls matched with propensity scoring. Univariate and multivariate Cox proportional hazards regression models were used to assess the risk of subsequent Parkinson's disease.

RESULTS

We observed 64 cases of Parkinson's disease in the HP infection group (1.7/1000 person-years), and 25 cases in the control group (0.7/1000 person-years). Overall, there was a significantly higher risk of Parkinson's disease in the HP infection group (adjusted hazard ratio [aHR]: 2.29, 95% confidence interval [CI]: 1.44-3.66). HP infection was significantly associated with an increased risk of Parkinson's disease among individuals who were ≥60 years old (aHR: 2.53, 95% CI: 1.47-4.35), but not among those <60 years old (aHR: 1.86, 95% CI: 0.69-4.98). Furthermore, HP infection was associated with an increased risk of Parkinson's disease among both men (aHR: 2.14, 95% CI: 1.15-3.96) and women (aHR: 2.84, 95% CI: 1.37-5.89). Nonetheless, eradication therapy was not significantly associated with the risk of Parkinson's disease (aHR: 1.07, 95% CI: 0.63-1.82).

CONCLUSION

Although HP infection was associated with an increased risk of Parkinson's disease, eradication therapy did not ameliorate this association. Further research is needed to explore the underlying biological mechanisms.

Higher dietary cholesterol and ω-3 fatty acid intakes are associated with a lower success rate of Helicobacter pylori eradication therapy in Japan

Background:Helicobacter pylori infection is a known risk factor for duodenal ulcers, gastritis, and gastric cancer. The eradication of H. pylori is successful in treating these disorders; however, the success rate of eradication therapy is declining. There may be an interaction with nutrient intake to account for this decline.Objective: We investigated the influence of food and nutrient intake on H. pylori eradication therapy.Design: In this study, 4014 subjects underwent endoscopy, were tested for serum antibodies to H. pylori (2046 positive; 51.0%), and had their food intake assessed with the use of a food-frequency questionnaire (FFQ). Of the positive subjects, endoscopies showed that 389 (19.0%) had gastritis and/or duodenal ulcers and were also positive for a ¹³C-urea breath test (UBT). These 389 subjects received 1-wk H. pylori eradication therapy with lansoprazole, amoxicillin, and clarithromycin and a second UBT 8 wk after treatment. Complete demographic characteristics, serum lipid, insulin, glycated hemoglobin, C-reactive protein (CRP), and creatinine concentrations as well as complete FFQs were available for 352 subjects. Multivariate logistic regression analyses were performed to determine factors that were associated with successful H. pylori eradication therapy.Results: The success rate of eradication therapy was 60.4% (235 of 389). Factors associated with the failure of eradication therapy included increased age (P = 0.02), higher CRP concentrations (P < 0.01), higher dietary cholesterol (P < 0.01) or egg intake (P < 0.01), higher ω-3 (n-3) fatty acid (P = 0.02) or fish intake (P = 0.01), and higher vitamin D intake (P = 0.02). Moreover, the higher vitamin D intake was strongly linked to higher fish intake. A limitation of the study is that we did not assess the antibiotic resistance of H. pyloriConclusions: Our results indicate that higher egg and fish intake may be negatively correlated with successful H. pylori eradication therapy in H. pylori-positive subjects with gastritis and/or duodenal ulcers.

Imbalance of Gastrointestinal Microbiota in the Pathogenesis of Helicobacter pylori-Associated Diseases

The development of new nucleotide sequencing techniques and advanced bioinformatics tools has opened the field for studying the diversity and complexity of the gastrointestinal microbiome independent of traditional cultural methods. Owing largely to the gastric acid barrier, the human stomach was long thought to be sterile. The discovery of Helicobacter pylori, the gram-negative bacterium that infects upwards of 50% of the global population, has started a major paradigm shift in our understanding of the stomach as an ecologic niche for bacteria. Recent sequencing analysis of gastric microbiota showed that H. pylori was not alone and the interaction of H. pylori with those microorganisms might play a part in H. pylori-associated diseases such as gastric cancer. In this review, we summarize the available literature about the changes of gastrointestinal microbiota after H. pylori infection in humans and animal models, and discuss the possible underlying mechanisms including the alterations of the gastric environment, the secretion of hormones and the degree of inflammatory response. In general, information regarding the composition and function of gastrointestinal microbiome is still in its infancy, future studies are needed to elucidate whether and to what extent H. pylori infection perturbs the established microbiota. It is assumed that clarifying the role of gastrointestinal communities in H. pylori-associated diseases will provide an opportunity for translational application as a biomarker for the risk of serious H. pylori diseases and perhaps identify specific organisms for therapeutic eradication.

Nutrition and Helicobacter pylori: Host Diet and Nutritional Immunity Influence Bacterial Virulence and Disease Outcome

Helicobacter pylori colonizes the stomachs of greater than 50% of the world's human population making it arguably one of the most successful bacterial pathogens. Chronic H. pylori colonization results in gastritis in nearly all patients; however in a subset of people, persistent infection with H. pylori is associated with an increased risk for more severe disease outcomes including B-cell lymphoma of mucosal-associated lymphoid tissue (MALT lymphoma) and invasive adenocarcinoma. Research aimed at elucidating determinants that mediate disease progression has revealed genetic differences in both humans and H. pylori which increase the risk for developing gastric cancer. Furthermore, host diet and nutrition status have been shown to influence H. pylori-associated disease outcomes. In this review we will discuss how H. pylori is able to create a replicative niche within the hostile host environment by subverting and modifying the host-generated immune response as well as successfully competing for limited nutrients such as transition metals by deploying an arsenal of metal acquisition proteins and virulence factors. Lastly, we will discuss how micronutrient availability or alterations in the gastric microbiome may exacerbate negative disease outcomes associated with H. pylori colonization.

Metabolic Interaction of Helicobacter pylori Infection and Gut Microbiota

As a barrier, gut commensal microbiota can protect against potential pathogenic microbes in the gastrointestinal tract. Crosstalk between gut microbes and immune cells promotes human intestinal homeostasis. Dysbiosis of gut microbiota has been implicated in the development of many human metabolic disorders like obesity, hepatic steatohepatitis, and insulin resistance in type 2 diabetes (T2D). Certain microbes, such as butyrate-producing bacteria, are lower in T2D patients. The transfer of intestinal microbiota from lean donors increases insulin sensitivity in individuals with metabolic syndrome, but the exact pathogenesis remains unclear. H. pylori in the human stomach cause chronic gastritis, peptic ulcers, and gastric cancers. H. pylori infection also induces insulin resistance and has been defined as a predisposing factor to T2D development. Gastric and fecal microbiota may have been changed in H. pylori-infected persons and mice to promote gastric inflammation and specific diseases. However, the interaction of H. pylori and gut microbiota in regulating host metabolism also remains unknown. Further studies aim to identify the H. pylori-microbiota-host metabolism axis and to test if H. pylori eradication or modification of gut microbiota can improve the control of human metabolic disorders.

Potential effect of chronic Helicobacter pylori infection on glucose metabolism of Mongolian gerbils

AIM: To assess the effect of Helicobacter pylori (H. pylori) infection on metabolic parameters in Mongolian gerbils.

METHODS: A total of 40 male, 5- to 8-wk-old, specific-pathogen-free Mongolian gerbils (30-50 g) were randomly allocated into two groups: a control group (n = 20) and an H. pylori group (n = 20). After a two-week acclimation period, the control group was administered Brucella broth and the H. pylori group was challenged intra-gastrically five times every other day with approximately 10⁹/CFU H. pylori ATCC43504 (CagA+, VacA+). Each group was then divided into two subgroups, which were sacrificed at either 6 or 12 mo. The control and H. pylori subgroups each contained 10 Mongolian gerbils. Body weight, abdominal circumference, and body length were measured, and body mass index (BMI) and Lee’s index were calculated. Biochemical assays were used to detect serum indexes, including glucose, glycated hemoglobin (GHb), glycated hemoglobin A1c (HbA1c), triacylglycerol, and total cholesterol, using an automatic biochemistry analyzer. Inflammatory cytokines, including interleukin (IL)-1β, IL-2, IL-4, IL-10, IL-12, tumor necrosis factor-α (TNF-α) and interferon (IFN)-γ, were assayed using ELISA. The expression of insulin and insulin-like growth factor 1 (IGF-1) was detected by immunohistochemistry, and islet apoptosis was measured using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay.

RESULTS: At each time point, body weight, abdominal circumference, BMI, and Lee’s index were increased after H. pylori infection. However, these differences were not significant. H. pylori infection significantly increased the GHb (5.45 ± 0.53 vs 4.98 ± 0.22, P < 0.05) and HbA1c (4.91 ± 0.61 vs 4.61 ± 0.15, P < 0.05) levels at 12 mo. We observed no significant differences in serum biochemical indexes, including fasting blood glucose, triacylglycerol and total cholesterol, at 6 or 12 mo after infection. H. pylori infection significantly increased the expression of IGF-1 (P < 0.05). Insulin levels from the pancreas and the apoptotic rate of islet β-cells remained unchanged. Also, we observed no significant differences among cytokines levels, including IL-1β, IL-2, IL-4, IL-10, IL-12, TNF-α and IFN-γ. IL-4 was the only exception, which increased at 6 (44.36 ± 25.17 vs 17.38 ± 3.47, P < 0.05) and 12 mo (33.41 ± 10.00 vs 18.91 ± 5.31, P < 0.05) after H. pylori infection.

CONCLUSION: Long-term H. pylori infection is significantly associated with high levels of HbA1c in Mongolian gerbils, indicating a potential role of H. pylori infection in glucose dysregulation.

Helicobacter pylori-Mediated Protection against Extra-Gastric Immune and Inflammatory Disorders: The Evidence and Controversies

A large number of studies link H. pylori infection with a reduced risk of developing extra-gastric conditions such as allergy, asthma, inflammatory bowel disease, coeliac disease and multiple sclerosis. The strength of the evidence for these protective associations is quite variable, and published studies often do not agree. This review article discusses some of the reasons for these discrepancies, and the difficulties faced when designing studies. Examples of some protective disease associations are described in detail, where the evidence is most abundant and thought to be more reliable. The most convincing of these are supported by published mechanistic data, for example with animal models, or incidence of disease exacerbation in humans following H. pylori eradication. Although controversial, this field is very important as the prevalence of H. pylori is decreasing throughout the world whilst many chronic diseases are becoming more common. These trends are likely to continue in the future, therefore it is important that we fully understand if and how H. pylori confers protection.

Helicobacter pylori infection reduces disease severity in an experimental model of multiple sclerosis

Recent research has demonstrated that infection with the bacterial pathogen Helicobacter pylori is less common amongst patients with multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS). We aimed to compare the prevalence of H. pylori amongst MS patients and healthy controls, and also investigated the impact of this infection on an animal model for MS, experimental autoimmune encephalomyelitis (EAE). The H. pylori status of 71 MS patients and 42 healthy controls was determined by serology. Groups of C57BL/6 mice were infected with H. pylori, or given diluent alone as a placebo, prior to inducing EAE. Clinical scores were assessed for all mice, and spleens and spinal cord tissue were harvested. CD4⁺ T cell subsets were quantified by flow cytometry, and T cell proliferation assays were performed. In MS patients the seroprevalence of H. pylori was half that of healthy controls (p = 0.018). Over three independent experiments, prior H. pylori infection had a moderate effect in reducing the severity of EAE (p = 0.012). In line with this, the antigen-specific T cell proliferative responses of infected animals were significantly reduced (p = 0.001), and there was a fourfold reduction in the number of CD4⁺ cells in the CNS. CD4⁺ populations in both the CNS and the spleens of infected mice also contained greatly reduced proportions of IFNγ⁺, IL-17⁺, T-bet⁺, and RORγt⁺ cells, but the proportions of Foxp3⁺ cells were equivalent. There were no differences in the frequency of splenic CD4⁺cells expressing markers of apoptosis between infected and uninfected animals. H. pylori was less prevalent amongst MS patients. In mice, the infection exerted some protection against EAE, inhibiting both Th1 and Th17 responses. This could not be explained by the presence of increased numbers of Foxp3⁺ regulatory T cells, or T cell apoptosis. This is the first direct experimental evidence showing that H. pylori may provide protection against inflammatory demyelination in the CNS.

The gastrointestinal microbiome - functional interference between stomach and intestine

The gastrointestinal (GI) tract is a complex and dynamic network with interplay between various gut mucosal cells and their defence molecules, the immune system, food particles, and the resident microbiota. This ecosystem acts as a functional unit organized as a semipermeable multi-layer system that allows the absorption of nutrients and macromolecules required for human metabolic processes and, on the other hand, protects the individual from potentially invasive microorganisms. Commensal microbiota and the host are a unique entity in a continuum along the GI tract, every change in one of these players is able to modify the whole homeostasis. In the stomach, Helicobacter pylori is a gram-negative pathogen that is widespread all over the world, infecting more than 50% of the world's population. In this scenario, H. pylori infection is associated with changes in the gastric microenvironment, which in turn affects the gastric microbiota composition, but also might trigger large intestinal microbiota changes. It is able to influence all the vital pathways of human system and also to influence microbiota composition along the GI tract. This can cause a change in the normal functions exerted by intestinal commensal microorganisms leading to a new gastrointestinal physiological balance. This review focuses and speculates on the possible interactions between gastric microorganisms and intestinal microbiota and on the consequences of this interplay in modulating gut health.

Streptococcus mitis induces conversion of Helicobacter pylori to coccoid cells during co-culture in vitro

Helicobacter pylori (H. pylori) is a major gastric pathogen that has been associated with humans for more than 60,000 years. H. pylori causes different gastric diseases including dyspepsia, ulcers and gastric cancers. Disease development depends on several factors including the infecting H. pylori strain, environmental and host factors. Another factor that might influence H. pylori colonization and diseases is the gastric microbiota that was overlooked for long because of the belief that human stomach was a hostile environment that cannot support microbial life. Once established, H. pylori mainly resides in the gastric mucosa and interacts with the resident bacteria. How these interactions impact on H. pylori-caused diseases has been poorly studied in human. In this study, we analyzed the interactions between H. pylori and two bacteria, Streptococcus mitis and Lactobacillus fermentum that are present in the stomach of both healthy and gastric disease human patients. We have found that S. mitis produced and released one or more diffusible factors that induce growth inhibition and coccoid conversion of H. pylori cells. In contrast, both H. pylori and L. fermentum secreted factors that promote survival of S. mitis during the stationary phase of growth. Using a metabolomics approach, we identified compounds that might be responsible for the conversion of H. pylori from spiral to coccoid cells. This study provide evidences that gastric bacteria influences H. pylori physiology and therefore possibly the diseases this bacterium causes.

Correlation between chronic treatment with proton pump inhibitors and bacterial overgrowth in the stomach: any possible beneficial role for selected lactobacilli?

BACKGROUND

The inhibition of physiological gastric acid secretion induced by proton pump inhibitors (PPIs), the most widely used drugs in the world, may cause a significant bacterial overgrowth in the gastrointestinal tract as a side effect. This study was undertaken firstly to correlate PPI intake with concentration of specific bacterial groups in the stomach as well as possible Helicobacter pylori infection, and secondly to assess the efficacy of the 4 lactobacilli L. rhamnosus LR06 (DSM 21981), L. pentosus LPS01 (DSM 21980), L. plantarum LP01 (LMG P-21021), and L. delbrueckii subsp. delbrueckii LDD01 (DSM 22106) in the restoration of a physiological gastric barrier.

METHODS

Total bacteria, sulphite-reducing bacteria (SRB), total coliforms, and total lactobacilli were quantified in samples of gastric juice from 29 subjects taking PPIs for at least 3 months compared with 36 control subjects. The presence of H. pylori was also assessed.The subjects treated with PPIs with a concentration of total bacteria in the gastric juice higher than 10(5) cells/mL were selected for an intervention study with the 4 lactobacilli L. rhamnosus LR06, L. pentosus LPS01, L. plantarum LP01, and L. delbrueckii subsp. delbrueckii LDD01. After 15 days of supplementation, the same bacterial groups were quantified to compare these values with the baseline.

RESULTS

No significant correlation was found between the presence of H. pylori and PPI intake. The baseline quantification of bacterial groups (log10 CFU/mL of gastric juice, PPI group vs. control) showed: total bacteria 8.35 versus 3.95 (P<0.001); total coliforms 4.98 versus 2.35 (P<0.001); SRB 5.71 versus 2.28 (P=0.065); and total lactobacilli 3.85 versus 2.20 (P=0.005). After 15 days of treatment with the 4 lactobacilli, the quantification of bacterial groups gave the following results: total bacteria 7.91 versus 8.35 at time zero (P=0.002); total coliforms 4.21 versus 4.98 at time zero (P<0.001); SRB 4.94 versus 5.71 at baseline (P=0.060); and total lactobacilli 7.20 versus 3.85 at baseline (P=0.040).

CONCLUSIONS

A significant impairment of intragastric acidity is sufficient to induce a relevant bacterial overgrowth, with particular reference to SRB and total coliforms. This fact can contribute to an increase in the risk of infections and intestinal diseases. It could be crucial to restore the physiological "gastric barrier." The 2-week supplementation with the 4 lactobacilli tested proved to be effective in significantly reducing total bacteria and coliforms in the gastric milieu in subjects chronically treated with PPIs. It is therefore possible to hopothesise a beneficial role for such lactobacilli in clinical practice.

Helicobacter pylori

PURPOSE OF REVIEW

This review focuses on new treatment options for eradicating Helicobacter pylori that have emerged as a result of decreased efficacy of standard triple therapy due to increasing antibiotic resistance. We also report on new data regarding primary and secondary gastric cancer prevention strategies and the potential role of H. pylori as a risk factor for extragastric malignancies.

RECENT FINDINGS

Treatment options have shifted from triple to various quadruple modifications. The length of therapy duration has, in general, been extended from 7 to 10 and 14 days. Nonbismuth-based quadruple therapies prescribed as sequential, concomitant, and hybrid have shown superiority as compared to standard triple therapy in the eradication of clarithromycin-resistant H. pylori. Bismuth-based quadruple therapy appears almost totally independent of antibiotic resistance and maintains high eradication rates. Levofloxacin is an adequate substitute for clarithromycin and is recommended in second-line regimens. However, it should be used prudently as H. pylori has developed resistance to levofloxacin in many regions of the world. Strategies for primary gastric cancer prevention by H. pylori eradication are effective, whereas H. pylori eradication for secondary gastric cancer prevention is uncertain. Very recent data implicate H. pylori as a risk factor for extragastric malignancies.

SUMMARY

H. pylori therapy should be tailored according to local antibiotic resistance patterns. In many regions of the world, H. pylori is becoming increasingly resistant to clarithromycin, metronidazole, and levofloxacin. Gastric cancer prevention by H. pylori eradication is most effective, if implemented early in the course of infection. New data are provided which indicate H. pylori as risk factor for extragastric malignancies.

Helicobacter pylori infection in Mongolian gerbils does not initiate hematological diseases

AIM: To investigate whether Helicobacter pylori (H. pylori) infection contributes to idiopathic thrombocytopenic purpura (ITP) or iron-deficiency anemia (IDA) onset in gerbils.

METHODS: A total of 135 Mongolian gerbils were randomly divided into two groups: an H. pylori infection group and a control group. Both groups were fed the same diet and the same amount of food. Each group was then divided into three subgroups, which were sacrificed at 6, 12, or 18 mo for analysis. At each time point, arterial blood was collected from the abdominal aorta and a complete blood cell count was analyzed in the clinical laboratory in the First Affiliated Hospital of Nanchang University.

RESULTS: There were no significant differences in platelet counts (938.00 ± 270.27/L vs 962.95 ± 162.56 × 10⁹/L), red blood cell counts (8.11 ± 1.25/L vs 8.44 ± 1.48 × 10¹²/L), or hemoglobin levels (136.9 ± 8.76 g/L vs 123.21 ± 18.42 g/L) between the control and the H. pylori groups, respectively, at 18 mo. With the exception of the mean corpuscular volume (MCV), all other indicators, including white blood cell counts, hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red blood cell distribution width, mean platelet volume, platelet distribution width, lymphocyte count, and lymphocyte count percentage, showed no significant differences between the control and H. pylori infection groups at each time point. The MCV in the H. pylori infection group (52.32 f/L ± 2.86 f/L) was significantly lower than the control group (55.63 ± 1.89 f/L) at 18 mo (P = 0.005), though no significant differences were observed at 6 (54.40 ± 2.44 f/L vs 53.30 ± 1.86 f/L) or 12 mo (53.73 ± 2.31 f/L vs 54.80 ± 3.34 f/L).

CONCLUSION: A single H. pylori infection is insufficient to cause onset of ITP or IDA and other factors may be required for disease onset.

Helicobacter pylori induced gastric immunopathology is associated with distinct microbiota changes in the large intestines of long-term infected Mongolian gerbils

Background

Gastrointestinal (GI) inflammation in mice and men are frequently accompanied by distinct changes of the GI microbiota composition at sites of inflammation. Helicobacter (H.) pylori infection results in gastric immunopathology accompanied by colonization of stomachs with bacterial species, which are usually restricted to the lower intestine. Potential microbiota shifts distal to the inflammatory process following long-term H. pylori infection, however, have not been studied so far.

Methodology/Principal Findings

For the first time, we investigated microbiota changes along the entire GI tract of Mongolian gerbils after 14 months of infection with H. pylori B8 wildtype (WT) or its isogenic ΔcagY mutant (MUT) strain which is defective in the type IV secretion system and thus unable to modulate specific host pathways. Comprehensive cultural analyses revealed that severe gastric diseases such as atrophic pangastritis and precancerous transformations were accompanied by elevated luminal loads of E. coli and enterococci in the caecum and together with Bacteroides/Prevotella spp. in the colon of H. pylori WT, but not MUT infected gerbils as compared to naïve animals. Strikingly, molecular analyses revealed that Akkermansia, an uncultivable species involved in mucus degradation, was exclusively abundant in large intestines of H. pylori WT, but not MUT infected nor naïve gerbils.

Conclusion/Significance

Taken together, long-term infection of Mongolian gerbils with a H. pylori WT strain displaying an intact type IV secretion system leads to distinct shifts of the microbiota composition in the distal uninflamed, but not proximal inflamed GI tract. Hence, H. pylori induced immunopathogenesis of the stomach, including hypochlorhydria and hypergastrinemia, might trigger large intestinal microbiota changes whereas the exact underlying mechanisms need to be further unraveled.

The role of the gastrointestinal microbiome in Helicobacter pylori pathogenesis

The discovery of Helicobacter pylori overturned the conventional dogma that the stomach was a sterile organ and that pH values<4 were capable of sterilizing the stomach. H. pylori are an etiological agent associated with gastritis, hypochlorhydria, duodenal ulcers, and gastric cancer. It is now appreciated that the human stomach supports a bacterial community with possibly 100s of bacterial species that influence stomach homeostasis. Other bacteria colonizing the stomach may also influence H. pylori-associated gastric pathogenesis by creating reactive oxygen and nitrogen species and modulating inflammatory responses. In this review, we summarize the available literature concerning the gastric microbiota in humans, mice, and Mongolian gerbils. We also discuss the gastric perturbations, many involving H. pylori, that facilitate the colonization by bacteria from other compartments of the gastrointestinal tract, and identify risk factors known to affect gastric homeostasis that contribute to changes in the microbiota.

Upper gastrointestinal microbiota and digestive diseases

Metagenomics which combines the power of genomics, bioinformatics, and systems biology, provide new access to the microbial world. Metagenomics permit the genetic analysis of complex microbial populations without requiring prior cultivation. Through the conceptual innovations in metagenomics and the improvements in DNA high-throughput sequencing and bioinformatics analysis technology, gastrointestinal microbiology has entered the metagenomics era and become a hot topic worldwide. Human microbiome research is underway, however, most studies in this area have focused on the composition and function of the intestinal microbiota and the relationship between intestinal microbiota and metabolic diseases (obesity, diabetes, metabolic syndrome, etc.) and intestinal disorders [inflammatory bowel disease, colorectal cancer, irritable bowel syndrome (IBS), etc.]. Few investigations on microbiota have been conducted within the upper gastrointestinal tract (esophagus, stomach and duodenum). The upper gastrointestinal microbiota is essential for several gastrointestinal illnesses, including esophagitis, Barrett’s esophagus, and esophageal carcinoma, gastritis and gastric cancer, small intestinal bacterial overgrowth, IBS and celiac disease. However, the constitution and diversity of the microbiota in different sections of the upper gastrointestinal tract under health and various disease states, as well as the function of microbiota in the pathogenesis of various digestive diseases are still undefined. The current article provides an overview of the recent findings regarding the relationship between upper gastrointestinal microbiota and gastrointestinal diseases; and discusses the study limitations and future directions of upper gastrointestinal microbiota research.