Virulence markers of Helicobacter pylori in patients with diarrhoea-dominant irritable bowel syndrome

No evidence for a causal link between Helicobacter pylori infection and Irritable bowel syndrome: a Mendelian randomization study

Background

Although clinical studies have revealed a potential link between Helicobacter pylori (H. pylori) infection and irritable bowel syndrome (IBS), the causal relationship between them remains unknown. The objective of this study was to investigate whether H. pylori infection is causally associated with IBS.

Method

A two-sample Mendelian randomization (MR) analysis using the inverse variance weighted (IVW), weighted mode, weighted median and MR-Egger methods was performed. We used the publicly available summary statistics data sets of genome-wide association studies (GWAS) for H. pylori infection in individuals of European descent (case = 1,058, control = 3,625) as the exposure and a GWAS for non-cancer illness code self-reported: IBS (case = 10,939, control = 451,994) as the outcome.

Results

We selected 10 single nucleotide polymorphisms at genome-wide significance from GWASs on H. pylori infection as the instrumental variables. The IVW, weighted mode, weighted median and MR-Egger methods all provided consistent evidence that suggests a lack of causal association between H. pylori and IBS. MR-Egger regression revealed that directional pleiotropy was unlikely to be biasing the result (intercept = -1e-04; P = 0.831). Cochran's Q-test and the funnel plot indicated no evidence of heterogeneity and asymmetry, indicating no directional pleiotropy.

Conclusion

The results of MR analysis support that H. pylori infection may not be causally associated with an increased risk of IBS.

Gut microbiota mediated the therapeutic efficiency of Simiao decoction in the treatment of gout arthritis mice

BACKGROUND

Gut microbiota plays a significant role in the development and treatment of gouty arthritis. Simiao decoction has been shown to alleviate gouty arthritis by inhibiting inflammation, regulating NLRP3 inflammasome, and altering gut microbiota. However, there is no evidence to prove whether gut microbiota directly mediates the therapeutic efficiency of Simiao decoction in treating gout arthritis.

METHODS

In this study, fecal microbiota transplantation (FMT) was used to transfer the gut microbiota of gout arthritis mice treated with Simiao decoction or allopurinol to blank gout arthritis mice, in order to investigate whether FMT had therapeutic effects on gout arthritis.

RESULTS

Both Simiao decoction and allopurinol effectively reduced the levels of serum uric acid, liver XOD activity, foot thickness, serum IL-1β, and G-CSF in gout arthritis mice. However, Simiao decoction also had additional benefits, including raising the pain threshold, reducing serum TNF-α and IL-6, alleviating gut inflammation, and repairing intestinal pathology, which were not observed with allopurinol treatment. Moreover, Simiao decoction had a greater impact on gut microbiota than allopurinol, as it was able to restore the abundance of phylum Proteobacteria and genus Helicobacter. After transplantation into gout arthritis mice, gut microbiota altered by Simiao decoction exhibited similar therapeutic effects to those of Simiao decoction, but gut microbiota altered by allopurinol showed no therapeutic effect.

CONCLUSIONS

These findings demonstrates that Simiao decoction can alleviate gout arthritis symptoms by regulating gut microbiota.

Helicobacter pylori Infection—A Risk Factor for Irritable Bowel Syndrome? An Updated Systematic Review and Meta-Analysis

Nowadays, the relationship between Helicobacter pylori infection (HPI) and irritable bowel syndrome (IBS) remains controversial. Objective: The aim of this study is to investigate the relationship between HPI and IBS through a systematic review and meta-analysis based on the current evidence. Methods: We performed a systematic literature search in electronic databases (PubMed, EMBASE, and the Cochrane library) by computer to identify all reports published before 8 August 2021. The odds ratio (OR) and confidence interval (CI) were calculated to evaluate the association between HPI and IBS. Subgroup analyses were conducted for further assessment and exploration of heterogeneity sources. In addition, we assessed publication bias through funnel plots, Egger’s test, and Begg’s test. Finally, we conducted a sensitivity analysis to evaluate the robustness of the results. Results: Thirteen studies with 13,173 participants were included in the meta-analysis. The pooled OR of the association between HPI and IBS was 1.03 (95% CI [0.80,1.31]; p = 0.84). The adjusted OR of the association between HPI and IBS after excluding the studies with confounding factors defined by our team was 1.29 (95% CI [1.03,1.62]; p = 0.03). We found a positive association between HPI and IBS-D (diarrhea subtype) (OR: 1.54; 95% CI [1.22,1.95]; p = 0.0003). The OR of the relationship between cytotoxin-associated gene A (Cag A) positive HPI and IBS was 4.3 (95% CI [0.51,36.17]; p = 0.18). Conclusions: The likelihood of HPI in IBS patients is relatively higher than that of non-IBS participants but not statistically significant, implying that HPI is not significantly associated with IBS, albeit we may underestimate this association. Moreover, we found a positive association between HPI and IBS-D. We also observed an increased likelihood of Cag-A positive HPI in IBS patients than that of non-IBS participants but not statistically significant.

Association between Helicobacter pylori infection and irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori infection and irritable bowel syndrome (IBS) negatively affect the quality of life. Some previous studies found that H. pylori infection should be positively associated with the risk of IBS, but others did not. The present study aims to clarify this association, and to further analyse whether H. pylori treatment can improve IBS symptoms.

MATERIALS AND METHODS

The PubMed, EMBASE, Cochrane library, Chinese National Knowledge Infrastructure, China Science and Technology Journal and Wanfang databases were searched. Meta-analysis was performed using a random-effect model. The pooled odds ratios (ORs)/risk ratios (RRs) and their 95% CIs were calculated. Heterogeneity was evaluated using the Cochran's Q test and I² statistics. Meta-regression analysis was used to explore the sources of heterogeneity.

RESULTS

Thirty-one studies with 21 867 individuals were included. Meta-analysis of 27 studies found that patients with IBS had a significantly higher risk of H. pylori infection than those without (OR=1.68, 95% CI 1.29 to 2.18; p<0.001). The heterogeneity was statistically significant (I^²=85%; p<0.001). Meta-regression analyses indicated that study design and diagnostic criteria of IBS might be the potential sources of heterogeneity. Meta-analysis of eight studies demonstrated that H. pylori eradication treatment had a higher improvement rate of IBS symptoms (RR=1.24, 95% CI 1.10 to 1.39; p<0.001). The heterogeneity was not significant (I^²=32%; p=0.170). Meta-analysis of four studies also demonstrated that successful H. pylori eradication had a higher improvement rate of IBS symptoms (RR=1.25, 95% CI 1.01 to 1.53; p=0.040). The heterogeneity was not significant (I^²=1%; p=0.390).

CONCLUSION

H. pylori infection is associated with an increased risk of IBS. H. pylori eradication treatment can improve IBS symptoms.

Inflammation and Overlap of Irritable Bowel Syndrome and Functional Dyspepsia

Irritable bowel syndrome (IBS) and functional dyspepsia (FD) are common functional gastrointestinal disorders (FGIDs) and account for a large proportion of consulting patients. These 2 disorders overlap with each other frequently. The pathogenesis of IBS or FD is complicated and multi-factors related, in which infectious or non-infectious inflammation and local or systemic immune response play significant roles. There are few studies focusing on the mechanism of inflammation in patients with overlap syndrome of irritable bowel syndrome and functional dyspepsia (IBS-FD). This review focuses on current advances about the role of inflammation in the pathogenesis of IBS and FD and the possible mechanism of inflammation in IBS-FD.

Association between Helicobacter pylori infection and irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

In recent years, the incidence of IBS has gradually increased, and it is considered as one of the most common functional gastrointestinal diseases. However, the etiology of IBS is still unclear, and expectations are rising for more targeted treatments. Many clinical trials have explored the link between Helicobacter pylori (H pylori) and IBS, with different conclusions. Therefore, we conducted a meta-analysis to explore whether there is an association between H pylori and IBS, which is of great significance for targeted treatment of IBS.

METHODS

We performed a systematic review and meta-analysis of the association between H pylori and IBS. We searched PubMed, EMBASE, Medline and the Cochrane Library to collect related studies. OR was used to describe the ratio of the probability of the H pylori infection occurring in IBS patients versus the controls. Heterogeneity was assessed by subgroup and meta-regression analysis.

RESULTS

Eight studies, including 1861 patients, assessed the association between H pylori infection and IBS. The OR of H pylori in IBS patients compared to controls was 1.32 (95% CI: 0.94-1.87; P = 0.11). Subgroup analyses showed a difference between IBS patients diagnosed with Roman III criteria and those diagnosed with non-Roman III criteria.

CONCLUSIONS

Our study suggests that H pylori may have a positive effect on the development of IBS. Although the differences were not statistically significant, there were significant differences among subgroups of patients. Considering the limitations and heterogeneity, high quality studies are needed to further explore the effect of H pylori on the development of IBS.

The Association between Helicobacter pylori Infection and Irritable Bowel Syndrome: A Meta-Analysis

The association of Helicobacter pylori (H. pylori) infection with functional dyspepsia has been well studied. However, the data on the relationship between H. pylori infection and irritable bowel syndrome (IBS) are conflicting. This study aims to elucidate the association between H. pylori infection and IBS. PubMed, Cochrane Library, CINAHL and SCOPUS databases were searched to identify eligible English articles published up to December 2019. Cross-sectional studies, case–control studies and cohort studies reporting both prevalence of H. pylori infection and IBS were selected for the detailed review. The pooled odds ratio (ORs) and their 95% confidence interval (CI) were calculated. A total of 7269 individuals in four cross-sectional studies and six case-control studies were included. The prevalence of H. pylori infection ranged from 12.8% to 73.4% in the control group, and 9.7% to 72.1% in the IBS group. The combined OR for H. pylori infection was 1.10 (95% CI: 0.93–1.29, I²: 37.5%). In a subgroup analysis of IBS defined according to Rome criteria, the OR for H. pylori infection was 1.10 (95% CI: 0.93–1.30, I² = 31.7%). In this meta-analysis, H. pylori infection was not significantly associated with IBS. Well-designed studies are needed to identify the relationship between H. pylori infection and IBS.

Is there an association between Helicobacter pylori infection and irritable bowel syndrome? A meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is a prevalent and debilitating gastrointestinal condition. Research has reported persistent, low-grade mucosal inflammation and significant overlaps between patients with IBS and those with dyspepsia, suggesting a possible pathogenic role of Helicobacter pylori (H. pylori) in IBS. This study therefore aimed to provide the first systematic review and meta-analysis on the association between H. pylori infection and IBS.

AIM

To investigate the association between H. pylori infection and IBS.

METHODS

Using the keywords "H. pylori OR Helicobacter OR Helicobacter pylori OR infection" AND "irritable bowel syndrome OR IBS", a preliminary search of PubMed, Medline, Embase, Cochrane Database of Systematic Reviews, Web of Science, Google Scholar and WanFang databases yielded 2924 papers published in English between 1 January 1960 and 1 June 2018. Attempts were also made to search grey literature.

RESULTS

A total of 13 clinical studies were systematically reviewed and nine studies were included in the final meta-analysis. Random-effects meta-analysis found a slight increased likelihood of H. pylori infection in patients with IBS, albeit this was not statistically significant (pooled odds ratio 1.47, 95% confidence interval: 0.90-2.40, P = 0.123). It must also be acknowledged that all of the available studies reported only crude odd ratios. H. pylori eradication therapy also does not appear to improve IBS symptoms. Although publication bias was not observed in the funnel plot, there was a high degree of heterogeneity amongst the studies included in the meta-analysis (I 2 = 87.38%).

CONCLUSION

Overall, current evidence does not support an association between IBS and H. pylori infection. Further rigorous and detailed studies with larger sample sizes and after H. pylori eradication therapy are warranted.

The possible role of bacteria, viruses, and parasites in initiation and exacerbation of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a prolonged and disabling functional gastrointestinal disorder with the incidence rate of 18% in the world. IBS could seriously affect lifetime of patients and cause high economic burden on the community. The pathophysiology of the IBS is hardly understood, whereas several possible mechanisms, such as visceral hypersensitivity, irregular gut motility, abnormal brain-gut relations, and the role of infectious agents, are implicated in initiation and development of this syndrome. Different studies demonstrated an alteration in B-lymphocytes, mast cells (MC), T-lymphocytes, and cytokine concentrations in intestinal mucosa or systemic circulation that are likely to contribute to the formation of the IBS. Therefore, IBS could be developed in those with genetic predisposition. Infections' role in initiation and exacerbation of IBS has been investigated by quite several clinical studies; moreover, the possible role of some pathogens in development and exacerbation of this disease has been described. It appears that the main obligatory pathogens correspond with the IBS disease, Clostridium difficile, Escherichia coli, Mycobacterium avium subspecies paratuberculosis, Campylobacter concisus, Campylobacter jejuni, Chlamydia trachomatis, Helicobacter pylori, Pseudomonas aeruginosa, Salmonella spp, Shigella spp, and viruses, particularly noroviruses. A number of pathogenic parasites (Blastocystis, Dientamoeba fragilis, and Giardia lamblia) may also be involved in the progression and exacerbation of the disease. Based on the current knowledge, the current study concludes that the most common bacterial, viral, and parasitic pathogens may be involved in the development and progression of IBS.

Blastocystis subtypes isolated from irritable bowel syndrome patients and co-infection with Helicobacter pylori

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disease presenting clinically by abdominal pain with alteration of bowel habits. Although IBS has uncertain etiology, chronic gut inflammation due to persistent exposure to an infectious agent including Blastocystis sp. was proposed. The aim of this study was to detect the prevalence of Blastocystis sp. subtype (ST) isolated from stool of IBS patients and to assess Blastocystis sp. and H. pylori co-infection in IBS patients from Beni-Suef Governorate, Egypt. Stool samples were collected from 115 IBS patients, following Rome III criteria. All stool samples were microscopically examined by wet mount and permanent trichrome stain, cultured on Jones' medium with further sequencing of positive Blastocystis isolates and screened for detection of H. pylori coproantigen. Blastocystis sp. was the predominant parasite in IBS patients; it had statistical significant association with both rural residence (OR = 10) and flatulence (OR = 8.2). There was a predominance of Blastocystis sp. ST3 (81%) followed by ST1 (19%). Blastocystis culture results (19.1%) were superior than microscopy (16.5%). The majority of Blastocystis-positive IBS patients (72.7%) were co-infected with H. pylori with statistical significance; however, H. pylori was higher in Blastocystis-negative IBS patients (47/64) than in Blastocystis-positive IBS patients (17/64). Interestingly, IBS is usually associated with gut dysbiosis, while the most prevalent parasite in our IBS patients was Blastocystis sp., which is frequently found in asymptomatic individuals. Whether Blastocystis sp. is a cause or a consequence of IBS still needs further investigation, with a particular focus on correlation of IBS with different Blastocystis sp. subtypes and gut microbiomes.

Lack of Association Found between Helicobacter pylori Infection and Diarrhea-Predominant Irritable Bowel Syndrome: A Multicenter Retrospective Study. Gastroenterol Res Pract. 2016;2016:3059201. [PMID: 27493660 PMCID: PMC4967462 DOI: 10.1155/2016/3059201]

Aims. The association between Helicobacter pylori (H. pylori) infection and diarrhea-predominant irritable bowel syndrome (IBS-D) is still controversial. Here we performed a retrospective study to explore this issue. Methods. A total of 502 inpatients with Rome III confirmed IBS-D and known H. pylori status from 8 hospitals were enrolled. H. pylori-positive patients, hospitalized in the recent year, were followed up to evaluate the effects of H. pylori eradication on IBS-D clinical course. Results. Of the 502 IBS-D patients, 206 were H. pylori-positive, with an infection rate that has no significant difference with that of the general population in Guangdong province (p = 0.348). For patients followed up, no significant differences were noted as to overall symptoms (p = 0.562), abdominal pain/discomfort (p = 0.777), bloating (p = 0.736), stool frequency (p = 0.835), or stool characteristics (p = 0.928) between the H. pylori-eradicated group and the control group. The results were the same in long-term follow-up patients except the improvement of bloating, which showed that the bloating score in the H. pylori-eradicated group was significantly lower (p = 0.047). Conclusions. No significant correlation between H. pylori infection and IBS-D was noted. Overall, IBS-D patients may not benefit from H. pylori eradication.

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.

Irritable bowel syndrome is associated with gastroesophageal reflux symptom but not erosive esophagitis

BACKGROUND/AIMS

Although several studies have suggested overlaps between gastroesophageal reflux symptom and irritable bowel syndrome (IBS), the studies for the association between erosive esophagitis and IBS are rare. The aim of this study was to evaluate the association among IBS, non-erosive reflux disease (NERD), and erosive esophagitis.

METHODS

A total of 2,769 participants completed questionnaires and underwent esophagogastroduodenoscopy and colonoscopy. IBS was diagnosed by Rome III; NERD was defined as heartburn or acid regurgitation occurring at least once per week without erosive esophagitis. Erosive esophagitis was defined by Los Angeles classification. Psychological distress was evaluated with modified 4 dimensions from revised Hopkins symptom checklist 90.

RESULTS

Psychological distress was associated with both IBS and NERD, but not with erosive esophagitis. IBS was associated with somatization (adjusted OR, 2.88; 95% CI, 1.55-5.36; P < 0.001), anxiety (adjusted OR, 2.82; 95% CI, 1.36-5.88; P = 0.005), and hostility (adjusted OR, 2.06; 95% CI, 1.10-3.87; P = 0.024) and NERD was associated with somatization (adjusted OR, 5.65; 95% CI, 2.92-10.98; P < 0.001) and anxiety (adjusted OR, 3.29; 95% CI, 1.47-7.34; P = 0.004). Erosive esophagitis was associated with somatization (adjusted OR, 2.69; 95% CI, 1.26-7.91; P < 0.001). Hiatal hernia and male sex were related with erosive esophagitis but not with IBS or NERD. H. pylori had an inverse relationship with erosive esophagitis, but had no association with IBS. Whereas IBS was positively associated with NERD (adjusted OR, 2.72; 95% CI, 1.84-4.03; P < 0.001), it had no association with erosive esophagitis.

CONCLUSIONS

IBS shared many risk factors with NERD but not with erosive esophagitis. It partially explains why IBS was associated with NERD, but not with erosive esophagitis.