Endoplasmic reticulum stress in the intestinal epithelium initiates purine metabolite synthesis and promotes Th17 cell differentiation in the gut.

Intestinal IL-17-producing T helper (Th17) cells are dependent on adherent microbes in the gut for their development. However, how microbial adherence to intestinal epithelial cells (IECs) promotes Th17 cell differentiation remains enigmatic. Here, we found that Th17 cell-inducing gut bacteria generated an unfolded protein response (UPR) in IECs. Furthermore, subtilase cytotoxin expression or genetic removal of X-box binding protein 1 (Xbp1) in IECs caused a UPR and increased Th17 cells, even in antibiotic-treated or germ-free conditions. Mechanistically, UPR activation in IECs enhanced their production of both reactive oxygen species (ROS) and purine metabolites. Treating mice with N-acetyl-cysteine or allopurinol to reduce ROS production and xanthine, respectively, decreased Th17 cells that were associated with an elevated UPR. Th17-related genes also correlated with ER stress and the UPR in humans with inflammatory bowel disease. Overall, we identify a mechanism of intestinal Th17 cell differentiation that emerges from an IEC-associated UPR.

Hybrid, High-Dose Dual and Bismuth Quadruple Therapies for First-Line Treatment of Helicobacter pylori Infection in Taiwan: A Multicenter, Open-Label, Randomized Trial.

INTRODUCTION: The study aimed to compare the efficacies and safety of 14-day hybrid therapy, 14-day high-dose dual therapy, and 10-day bismuth quadruple therapy in the first-line treatment of Helicobacter pylori infections. METHODS: In this multicenter, open-label, randomized trial, we recruited adult H. pylori -infected patients from 9 centers in Taiwan. Subjects were randomly assigned (1:1:1) to 14-day hybrid therapy, 14-day high-dose dual therapy, or 10-day bismuth quadruple therapy. Eradication status was determined by the 13 C-urea breath test. The primary outcome was the eradication rate of H. pylori assessed in the intention-to-treat population. RESULTS: Between August 1, 2018, and December 2021, 918 patients were randomly assigned in this study. The intention-to-treat eradication rates were 91.5% (280/306; 95% confidence interval [CI] 88.4%-94.6%) for 14-day hybrid therapy, 83.3% (255/306; 95% CI 87.8%-95.0%) for 14-day high-dose dual therapy, and 90.2% (276/306; 95% CI 87.8%-95.0%) for 10-day bismuth quadruple therapy. Both hybrid therapy (difference 8.2%; 95% CI 4.5%-11.9%; P = 0.002) and bismuth quadruple therapy (difference 6.9%; 95% CI 1.6%-12.2%; P = 0.012) were superior to high-dose dual therapy and were similar to one another. The frequency of adverse events was 27% (81/303) with 14-day hybrid therapy, 13% (40/305) with 14-day high-dose dual therapy, and 32% (96/303) with 10-day bismuth quadruple therapy. Patients receiving high-dose dual therapy had the fewest adverse events (both P < 0.001). DISCUSSION: Fourteen-day hybrid therapy and 10-day bismuth quadruple therapy are more effective than 14-day high-dose dual therapy in the first-line treatment of H. pylori infection in Taiwan. However, high-dose dual therapy has fewer adverse effects than hybrid bismuth quadruple therapies.

Tetracycline-levofloxacin versus amoxicillin-levofloxacin quadruple therapies in the second-line treatment of Helicobacter pylori infection.

BACKGROUND: The Maastricht V/Florence Consensus Report recommends amoxicillin-fluoroquinolone triple or quadruple therapy as a second-line treatment for Helicobacter pylori infection. An important caveat of amoxicillin-fluoroquinolone rescue therapy is poor eradication efficacy in the presence of fluoroquinolone resistance. The study aimed to investigate the efficacies of tetracycline-levofloxacin (TL) quadruple therapy and amoxicillin-levofloxacin (AL) quadruple therapy in the second-line treatment of H. pylori infection. METHODS: Consecutive H. pylori-infected subjects after the failure of first-line therapies were randomly allocated to receive either TL quadruple therapy (tetracycline 500 mg QID, levofloxacin 500 mg QD, esomeprazole 40 mg BID, and tripotassium dicitrato bismuthate 300 mg QID) or AL quadruple therapy (amoxicillin 500 mg QID, levofloxacin 500 mg QD, esomeprazole 40 mg BID, and tripotassium dicitrato bismuthate 300 mg QID) for 10 days. Post-treatment H. pylori status was assessed 6 weeks after the end of therapy. RESULTS: The study was early terminated after an interim analysis. In the TL quadruple group, 50 out of 56 patients (89.3%) had successful eradication of H. pylori infection. Cure of H. pylori infection was achieved only in 39 of 52 patients (69.6%) receiving AL quadruple therapy. Intention-to-treat analysis showed that TL quadruple therapy achieved a markedly higher eradication rate than AL quadruple therapy (95% confidence interval: 4.8% to 34.6%; p = 0.010). Further analysis revealed that TL quadruple therapy had a high eradication rate for both levofloxacin-susceptible and resistant strains (100% and 88.9%). In contrast, AL quadruple therapy yielded a high eradication for levofloxacin-susceptible strains (90.9%) but a poor eradication efficacy for levofloxacin-resistant strains (50.0%). The two therapies exhibited comparable frequencies of adverse events (37.5% vs 21.4%) and drug adherence (98.2% vs 94.6%). CONCLUSIONS: Ten-day TL quadruple therapy is more effective than AL quadruple therapy in the second-line treatment of H. pylori infection in a population with high levofloxacin resistance.

Berberine alleviates visceral hypersensitivity in rats by altering gut microbiome and suppressing spinal microglial activation.

Accumulating evidence shows that agents targeting gut dysbiosis are effective for improving symptoms of irritable bowel syndrome (IBS). However, the potential mechanisms remain unclear. In this study we investigated the effects of berberine on the microbiota-gut-brain axis in two rat models of visceral hypersensitivity, i.e., specific pathogen-free SD rats subjected to chronic water avoidance stress (WAS) and treated with berberine (200 mg· kg-1 ·d-1, ig, for 10 days) as well as germ-free (GF) rats subjected to fecal microbiota transplantation (FMT) from a patient with IBS (designated IBS-FMT) and treated with berberine (200 mg· kg-1 ·d-1, ig, for 2 weeks). Before the rats were sacrificed, visceral sensation and depressive behaviors were evaluated. Then colonic tryptase was measured and microglial activation in the dorsal lumbar spinal cord was assessed. The fecal microbiota was profiled using 16S rRNA sequencing, and short chain fatty acids (SCFAs) were measured. We showed that berberine treatment significantly alleviated chronic WAS-induced visceral hypersensitivity and activation of colonic mast cells and microglia in the dorsal lumbar spinal cord. Transfer of fecal samples from berberine-treated stressed donors to GF rats protected against acute WAS. FMT from a patient with IBS induced visceral hypersensitivity and pro-inflammatory phenotype in microglia, while berberine treatment reversed the microglial activation and altered microbial composition and function and SCFA profiles in stools of IBS-FMT rats. We demonstrated that berberine did not directly influence LPS-induced microglial activation in vitro. In both models, several SCFA-producing genera were enriched by berberine treatment, and positively correlated to the morphological parameters of microglia. In conclusion, activation of microglia in the dorsal lumbar spinal cord was involved in the pathogenesis of IBS caused by dysregulation of the microbiota-gut-brain axis, and the berberine-altered gut microbiome mediated the modulatory effects of the agent on microglial activation and visceral hypersensitivity, providing a potential option for the treatment of IBS.

Distinct Physiological Characteristics of Isolated Laryngopharyngeal Reflux Symptoms.

BACKGROUND & AIMS: Patients with isolated laryngopharyngeal reflux symptoms (LPRS) defined as those without concomitant typical reflux symptoms (CTRS) are clinically challenging to manage due to unclear pathophysiology. We investigated esophageal physiology in patients with isolated LPRS and their response to proton-pump inhibitors (PPI) therapy. METHODS: This is a multi-center observational study conducted in referral hospitals in Taiwan. Patients with predominant LPRS, but without common non-reflux causes, underwent esophageal manometry, 24-hr ambulatory esophagopharyngeal pH testing, and Bernstein test, followed by a 12-week esomeprazole 40 mg twice-daily treatment. Participants with pathological reflux were divided into the isolated LPRS group (ie, LPRS without CTRS, n = 40) and the CTRS group (ie, LPRS with CTRS, n = 66). Participants without pathological reflux or esophagitis (n = 132) served as the nonreflux controls. RESULTS: The PPI-responsiveness was similar between the isolated LPRS group and CTRS group (63% vs 57%, P = .8), but lower in the nonreflux controls (32%, P = .005). Despite similar distal esophageal acid exposure time (P = .7) when compared to those with CTRS, the isolated LPRS group had a lower prevalence of both positive Bernstein test (P = .001) and ineffective esophageal motility disorder (P = .03), and fewer pharyngeal acid reflux episodes (P < .0001). CONCLUSIONS: Our findings indicate similar distal esophageal acid exposure and PPI-responsiveness between LPRS patients with and without CTRS. The lack of CTRS in the isolated LPRS group is likely due to esophageal acid hyposensitivity and fewer pharyngeal acid reflux episodes, thus implicating distinct pathophysiology of isolated LPRS from those with CTRS.

Dendritic cell-derived TGF-ß mediates the induction of mucosal regulatory T-cell response to Helicobacter infection essential for maintenance of immune tolerance in mice.

BACKGROUND: Helicobacter pylori infection leads to regulatory T-cell (Treg) induction in infected mice, which contributes to H. pylori immune escape. However, the mechanisms responsible for H. pylori induction of Treg and immune tolerance remain unclear. We hypothesized DC-produced TGF-ß may be responsible for Treg induction and immune tolerance. MATERIALS AND METHODS: To test this hypothesis, we generated TGF-ß∆DC mice (CD11c+ DC-specific TGF-ß deletion) and assessed the impact of DC-specific TGF-ß deletion on DC function during Helicobacter infection in vitro and in vivo. To examine the T cell-independent DC function, we crossed TGF-ß∆DC mice onto Rag1KO background to generate TGF-ß∆DC xRag1KO mice. RESULTS: When stimulated with H. pylori, TGF-ß∆DC BMDC/splenocyte cocultures showed increased levels of proinflammatory cytokines and decreased levels of anti-inflammatory cytokines compared to control, indicating a proinflammatory DC phenotype. Following 6 months of H. felis infection, TGF-ß∆DC mice developed more severe gastritis and a trend toward more metaplasia compared to TGF-ßfl/fl with increased levels of inflammatory Th1 cytokine mRNA and lower gastric H. felis colonization compared to infected TGF-ßfl/fl mice. In a T cell-deficient background using TGF-ß∆DC xRag1KO mice, H. felis colonization was significantly lower when DC-derived TGF-ß was absent, revealing a direct, innate function of DC in controlling H. felis infection independent of Treg induction. CONCLUSIONS: Our findings indicate that DC-derived TGF-ß mediates Helicobacter-induced Treg response and attenuates the inflammatory Th1 response. We also demonstrated a previously unrecognized innate role of DC controlling Helicobacter colonization via a Treg-independent mechanism. DC TGF-ß signaling may represent an important target in the management of H. pylori.

Equivalent efficacies of reverse hybrid and concomitant therapies in first-line treatment of Helicobacter pylori infection.

BACKGROUND AND AIM: Concomitant therapy is a recommended first-line treatment for Helicobacter pylori infection in most national or international consensuses. Reverse hybrid therapy is a modified 14-day concomitant therapy without clarithromycin and metronidazole in the final 7 days. This study aims to test whether 14-day reverse hybrid therapy is non-inferior to 14-day concomitant therapy in the first-line treatment of H. pylori infection. METHODS: Helicobacter pylori-infected adult patients were randomly assigned to receive either reverse hybrid therapy (dexlansoprazole 60 mg o.d. plus amoxicillin 1 g b.d. for 14 days, and clarithromycin 500 mg plus metronidazole 500 mg b.d. for initial 7 days) or concomitant therapy (dexlansoprazole 60 mg once o.d. plus amoxicillin 1 g, clarithromycin 500 mg, and metronidazole 500 mg b.d. for 14 days). H. pylori status was assessed 6 weeks after the end of treatment. RESULTS: Helicobacter pylori-infected participants (n = 248) were randomized to receive either 14-day reverse hybrid therapy (n = 124) or 14-day concomitant therapy (n = 124). Intention-to-treat analysis demonstrated that the two therapies had comparable eradication rate (95.2% vs 93.5%; 95% confidence interval, -4.0% to 7.4%; P = 0.582). However, reverse hybrid therapy had a much lower frequency of adverse events than concomitant therapy (20.2% vs 38.7%, P = 0.001). The two therapies exhibited comparable drug adherence (93.5% vs 87.9%, P = 0.125). CONCLUSIONS: Fourteen-day reverse hybrid therapy and 14-day concomitant therapy are equivalent in efficacy for the first-line treatment of H. pylori infection. However, reverse hybrid therapy has fewer adverse events compared with concomitant therapy.

Effects of Anti-Helicobacter pylori Therapy on Incidence of Autoimmune Diseases, Including Inflammatory Bowel Diseases.

BACKGROUND & AIMS: Helicobacter pylori induces immune tolerance and is associated with a lower risk for immune-mediated disorders, such as autoimmune and inflammatory bowel diseases (IBD). We aimed to determine the effects of treatment for H pylori infection on the incidence of autoimmune disease and IBD. METHODS: We collected data from the National Health Insurance Research Database in Taiwan on patients younger than 18 years old without a prior diagnosis of autoimmune disease or IBD. Patients with peptic ulcer disease (PUD) with treatment of H pylori infection (PUD+HPRx), PUD without H pylori treatment (PUD-HPRx), a urinary tract infection (UTI) treated with cephalosporin, or without PUD (controls) were matched for age, sex, insurance, and Charlson's comorbidity index score. RESULTS: Of the 1 million patients we collected data from in 2005, we included 79,181 patients in the study. We compared the effects of treatment for H pylori infection on the risk of autoimmunity or IBD and found that PUD+HPRx has the highest adjusted hazard risk (aHR) for autoimmunity or IBD (aHR, 2.36), compared to PUD-HPRx (aHR, 1.91) or UTI (aHRs, 1.71) (P < .001). The increased risk of autoimmune disease was not completely accounted for by antibiotic therapy alone, because PUD+HPRx had a higher aHR than UTI (P < .001). A small but significant increase in mortality was observed in the PUD+HPRx cohort (aHR, 1.11; P = .001). CONCLUSION: In an analysis of data from the National Health Insurance Research Database in Taiwan, we found that treatment for H pylori infection is associated with a significant increase in the risk for autoimmune disease, including IBD.

Indoleamine 2,3-Dioxygenase 1, Increased in Human Gastric Pre-Neoplasia, Promotes Inflammation and Metaplasia in Mice and Is Associated With Type II Hypersensitivity/Autoimmunity.

BACKGROUND & AIMS: Chronic gastrointestinal inflammation increases the risk of cancer by mechanisms that are not well understood. Indoleamine-2,3-dioxygenase 1 (IDO1) is a heme-binding enzyme that regulates the immune response via catabolization and regulation of tryptophan availability for immune cell uptake. IDO1 expression is increased during the transition from chronic inflammation to gastric metaplasia. We investigated whether IDO1 contributes to the inflammatory response that mediates loss of parietal cells leading to metaplasia. METHODS: Chronic gastric inflammation was induced in Ido1-/- and CB57BL/6 (control) mice by gavage with Helicobacter felis or overexpression of interferon gamma in gastric parietal cells. We also performed studies in Jh-/- mice, which are devoid of B cells. Gastric tissues were collected and analyzed by flow cytometry, immunostaining, and real-time quantitative polymerase chain reaction. Plasma samples were analyzed by enzyme-linked immunosorbent assay. Gastric tissues were obtained from 20 patients with gastric metaplasia and 20 patients without gastric metaplasia (controls) and analyzed by real-time quantitative polymerase chain reaction; gastric tissue arrays were analyzed by immunohistochemistry. We collected genetic information on gastric cancers from The Cancer Genome Atlas database. RESULTS: H felis gavage induced significantly lower levels of pseudopyloric metaplasia in Ido1-/- mice, which had lower frequencies of gastric B cells, than in control mice. Blood plasma from H felis-infected control mice had increased levels of autoantibodies against parietal cells, compared to uninfected control mice, but this increase was lower in Ido1-/- mice. Chronically inflamed stomachs of Ido1-/- mice had significantly lower frequencies of natural killer cells in contact with parietal cells, compared with stomachs of control mice. Jh-/- mice had lower levels of pseudopyloric metaplasia than control mice in response to H felis infection. Human gastric pre-neoplasia and carcinoma specimens had increased levels of IDO1 messenger RNA compared with control gastric tissues, and IDO1 protein colocalized with B cells. Co-clustering of IDO1 messenger RNA with B-cell markers was corroborated by The Cancer Genome Atlas database. CONCLUSIONS: IDO1 mediates gastric metaplasia by regulating the B-cell compartment. This process appears to be associated with type II hypersensitivity/autoimmunity. The role of autoimmunity in the progression of pseudopyloric metaplasia warrants further investigation.

Short-term and long-term impacts of Helicobacter pylori eradication with reverse hybrid therapy on the gut microbiota.

BACKGROUND AND AIMS: Anti-Helicobacter pylori therapy may lead to the growth of pathogenic or antibiotic-resistant bacteria in the gut. The study aimed to investigate the short-term and long-term impacts of H. pylori eradication with reverse hybrid therapy on the components and macrolide resistance of the gut microbiota. METHODS: Helicobacter pylori-related gastritis patients were administered a 14-day reverse hybrid therapy. Fecal samples were collected before treatment and at the end of week 2, week 8, and week 48. The V3-V4 region of the bacterial 16S rRNA gene in fecal specimens was amplified by polymerase chain reaction and sequenced on Illumina MiSeq platform. Additionally, amplification of erm(B) gene (encoding erythromycin resistance methylase) was performed. RESULTS: Reverse hybrid therapy resulted in decreased relative abundances of Firmicutes (from 62.0% to 30.7%; P < 0.001) and Actinobacteria (from 3.4% to 0.6%; 0.032) at the end of therapy. In contrast, the relative abundance of Proteobacteria increased from 10.2% to 49.1% (0.002). These microbiota alterations did not persist but returned to the initial levels at week 8 and week 48. The amount of erm(B) gene in fecal specimens was comparable with the pretreatment level at week 2 but increased at week 8 (0.025) and then returned to the pretreatment level by week 48. CONCLUSIONS: Helicobacter pylori eradication with reverse hybrid therapy can lead to short-term gut dysbiosis. The amount of erm(B) gene in the stool increased transiently after treatment and returned to the pretreatment level at 1-year post-treatment.

Early timing of single balloon enteroscopy is associated with increased diagnostic yield in patients with overt small bowel bleeding.

BACKGROUND/PURPOSE: Although performing balloon enteroscopy soon after the onset of small bowel bleeding appeared to enhance diagnostic rate, the optimal timing was unclear. METHODS: A retrospective cohort study in a single referral center. Patients with overt, suspected small bowel bleeding who underwent primary single-balloon enteroscopy (SBE) were evaluated to determine the association between procedure timing and diagnostic yield rates. RESULTS: A total of 220 patients were enrolled (47.7% males; mean age, 65.6 ± 18.1 years). They were stratified into four groups based on the timing of SBE: emergency (<24 h after onset or continued bleeding, n = 64), 24-72 h (n = 28), 3-7 days (n = 41), and >7 days (n = 87). A significant trend of decreasing diagnostic yields was observed across the groups (90.6%, 67.9%, 68.3%, and 44.8%, respectively, P < 0.0001). Diagnostic yield rates were different between emergency and 24-72 h groups (P < 0.0001), and between 3 and 7 days and >7 days groups (P < 0.05), but not between 24 and 72 h and 3-7 days groups (P = 0.97). In multivariate regression analysis, emergency, ≤ 3 days, and ≤7 days SBEs had greater yield rates than SBEs at later timings. CONCLUSION: The likelihood of diagnostic yield was highest when SBE was performed during continued bleeding or within 24 h of onset, and gradually declined as waiting time increased. We therefore recommend that SBE should be performed as soon as possible, preferably no later than seven days.

Chemotaxis Allows Bacteria To Overcome Host-Generated Reactive Oxygen Species That Constrain Gland Colonization.

The epithelial layer of the gastrointestinal tract contains invaginations, called glands or crypts, which are colonized by symbiotic and pathogenic microorganisms and may function as designated niches for certain species. Factors that control gland colonization are poorly understood, but bacterial chemotaxis aids occupation of these sites. We report here that a Helicobacter pylori cytoplasmic chemoreceptor, TlpD, is required for gland colonization in the stomach. tlpD mutants demonstrate gland colonization defects characterized by a reduction in the percentage of glands colonized but not in the number of bacteria per gland. Consistent with TlpD's reported role in reactive oxygen species (ROS) avoidance, tlpD mutants showed hallmarks of exposure to high ROS. To assess the role of host-generated ROS in TlpD-dependent gland colonization, we utilized mice that lack either the ability to generate epithelial hydrogen peroxide or immune cell superoxide. tlpD gland colonization defects were rescued to wild-type H. pylori levels in both of these mutants. These results suggest that multiple types of innate immune-generated ROS production limit gland colonization and that bacteria have evolved specific mechanisms to sense and direct their motility in response to this signal and thus spread throughout tissue.

Houston Consensus Conference on Testing for Helicobacter pylori Infection in the United States.

Despite guidelines for detection and treatment of Helicobacter pylori infection, recommendations to test patients before and after therapy are commonly not followed in the United States. At the Houston Consensus Conference, 11 experts on management of adult and pediatric patients with H pylori, from different geographic regions of the United States, met to discuss key factors in diagnosis of H pylori infection, including identification of appropriate patients for testing, effects of antibiotic susceptibility on testing and treatment, appropriate methods for confirmation of infection and eradication, and relevant health system considerations. The experts divided into groups that used a modified Delphi panel approach to assess appropriate patients for testing, testing for antibiotic susceptibility and treatment, and test methods and confirmation of eradication. The quality of evidence and strength of recommendations were evaluated using the GRADE system. The results of the individual workshops were presented for a final consensus vote by all panel members. After the Expert Consensus Development meeting, the conclusions were validated by a separate panel of gastroenterologists, who assessed their level of agreement with each of the 29 statements developed at the Expert Consensus Development. The final recommendations are provided, on the basis of the best available evidence, and provide consensus statements with supporting literature to implement testing for H pylori infection at health care systems across the United States.

Equivalent Efficacies of Reverse Hybrid and Bismuth Quadruple Therapies in Eradication of Helicobacter pylori Infection in a Randomized Controlled Trial.

BACKGROUND & AIMS: Bismuth quadruple therapy is recommended as a first-line treatment for Helicobacter pylori infection in the United States but hybrid therapy is an alternative option. Reverse hybrid therapy (proton pump inhibitor plus amoxicillin for 14 days, and clarithromycin plus metronidazole for the initial 7 days) is a simplified hybrid treatment. We aimed to assess the efficacies of reverse hybrid therapy vs bismuth quadruple therapy as first-line treatments for patients with H pylori infection in a randomized trial. METHODS: In a prospective study, patients with H pylori infection were randomly assigned to groups that received either reverse hybrid therapy (n = 176) or a bismuth quadruple therapy (pantoprazole, bismuth, tetracycline, and metronidazole for 14 days; n = 176). Patients were examined the end of therapy for adverse events. The study was performed from August 2015 through February 2017. The primary outcome was cure of H pylori infection, determined based on a negative result from the urea breath test, or negative results from histologic analysis, the urease test, and bacterial culture analyses. RESULTS: H pylori infection was eradicated from 96.6% of patients who received reverse hybrid therapy and 96.0% who received bismuth quadruple therapy-this difference was not significant in the intention-to-treat analysis (95% CI, 8.0% ∼ 2.2%; P = .281). There were no significant differences between therapies eradication of clarithromycin-resistant strains (88.2% with reverse hybrid therapy vs 92.3% with bismuth quadruple therapy) or metronidazole-resistant strains (100% vs 96.9%). However, reverse hybrid therapy was associated with fewer adverse events (18.7% of patients) than bismuth quadruple therapy (47.7%) (P < .001). CONCLUSIONS: In a randomized trial, we found 14-day reverse hybrid therapy to not be inferior to bismuth quadruple therapy as a first-line treatment for H pylori infection. Reverse hybrid therapy was associated with fewer adverse events. ClincialTrials.gov no: NCT02547038.

Helicobacter pylori eradication with bismuth quadruple therapy leads to dysbiosis of gut microbiota with an increased relative abundance of Proteobacteria and decreased relative abundances of Bacteroidetes and Actinobacteria.

BACKGROUND: Bismuth quadruple therapy is the treatment of choice for the first-line therapy of Helicobacter pylori infection in areas of high clarithromycin resistance. Currently, the impact of the promising treatment on gut microbiota remains unclear. AIM: To investigate the short-term and long-term impacts of bismuth quadruple therapy on gut microbiota. METHODS: Adult patients with H. pylori-related gastritis were treated with 14-day bismuth quadruple therapy. Fecal samples were collected before treatment at week 2, week 8, and week 48. Nucleic acid extraction from fecal samples was performed. The V3-V4 region of the bacterial 16S rRNA gene was amplified by polymerase chain reaction and sequenced with the MiSeq followed by data analysis using Qiime pipeline. RESULTS: Eleven patients received complete follow-up. Before treatment, the most abundant phyla were Firmicutes (45.3%), Bacteroidetes (24.3%), Proteobacteria (9.9%), and Actinobacteria (5.0%). At the end of bismuth therapy, the relative abundances of Bacteroidetes and Actinobacteria decreased to 0.5% (P < .001) and 1.3% (P = .038), respectively. Additionally, the relative abundance of Verrucomicrobia also decreased from 3.2% to 1.11E-3% (P = .034). In contrast, the relative abundances of Proteobacteria and Cyanobacteria increased (P < .001 and P = .003, respectively). At week 8, the relative abundances of all phyla restored to the levels at baseline. The relative abundances of all phyla at week 48 also did not significantly differ from those at baseline. During eradication therapy, 6 patients (55%) reported at least 1 adverse event. The relative abundance of phylum Proteobacteria in patients with adverse effects was more than that in patients without adverse effects (68.7% ± 8.8% vs 43.4% ± 25.5%; P = .048). CONCLUSIONS: Bismuth quadruple therapy for H. pylori eradication can lead to short-term dysbiosis of gut microbiota. The increase in Proteobacteria in gut microbiota may attribute to the development of adverse effects during bismuth quadruple therapy.

Helicobacter pylori Antimicrobial Susceptibility Testing-Guided Salvage Therapy in the USA: A Real Life Experience.

BACKGROUND: The current practice guidelines recommend that Helicobacter pylori (H. pylori) culture and antimicrobial susceptibility testing (AST) be considered after patients failed the second course of H. pylori eradication therapy. AIMS: Here we report the real life experience of following this recommendation in the USA. METHODS: We established an in-house H. pylori culture protocol for AST and identified retrospectively patients who previously failed ≥ 2 courses of anti-H. pylori therapy and underwent esophagogastroduodenoscopy with AST at University of Michigan from 2010 to 2017. We determined the rate of H. pylori antibiotic resistance, the success rates of AST-guided tailored therapy, and the risk factors associated with treatment failure. RESULTS: Forty-seven patients were identified and 34 (72.3%) had successful cultures and AST. The most common antibiotic resistance was to metronidazole (79.4%), followed by clarithromycin (70.6%) and ciprofloxacin (42.9%). None of the patients were resistant to amoxicillin or tetracycline. The overall success rate of AST-guided tailored therapy was low (44.4%, 12/27). In patients infected with metronidazole-resistant H. pylori, bismuth quadruple therapy appears to be superior compared to non-bismuth quadruple therapy (6/8 or 75.0% vs. 3/14 or 21.4%, P = 0.03). High body mass index was significantly associated with tailored therapy failure (OR 1.24, 95% CI 1.00-1.54, P = 0.049). CONCLUSIONS: The success rate of AST-guided salvage therapy in the USA is low particularly in those with high BMI. Bismuth-based therapy appears to be better than non-bismuth-based regimens.

Restoration of short chain fatty acid and bile acid metabolism following fecal microbiota transplantation in patients with recurrent Clostridium difficile infection.

A significant proportion of individuals develop recurrent Clostridium difficile infection (CDI) following initial disease. Fecal microbiota transplantation (FMT), a highly effective treatment method for recurrent CDI, has been demonstrated to induce microbiota recovery. One of the proposed functions associated with restoration of colonization resistance against C. difficile has been recovery of bile acid metabolism. In this study, we aimed to assess recovery of short chain fatty acids (SCFAs) in addition to bile acids alongside microbial community structure in six patients with recurrent CDI following treatment with FMT over time. Using 16S rRNA gene-based sequencing, we observed marked similarity of the microbiota between recipients following FMT (n = 6, sampling up to 6 months post-FMT) and their respective donors. Sustained increases in the levels of the SCFAs butyrate, acetate, and propionate were observed post-FMT, and variable recovery over time was observed in the secondary bile acids deoxycholate and lithocholate. To correlate these changes with specific microbial taxa at an individual level, we applied a generalized estimating equation approach to model metabolite concentrations with the presence of specific members of the microbiota. Metabolites that increased following FMT were associated with bacteria classified within the Lachnospiraceae, Ruminococcaceae, and unclassified Clostridiales families. In contrast, members of these taxa were inversely associated with primary bile acids. The longitudinal aspect of this study allowed us to characterize individualized patterns of recovery, revealing variability between and within patients following FMT.

CCR2 mediates Helicobacter pylori-induced immune tolerance and contributes to mucosal homeostasis.

BACKGROUND: We previously demonstrated that H. pylori infection leads to increased induction of regulatory T cells in local and systemic immune compartments. Here, we investigate the role of CCR2 in the tolerogenic programing of dendritic cells in a mouse model of H. pylori infection. MATERIALS AND METHODS: CCR2 deficient (CCR2KO) mice and wild-type (Wt) mice infected with H. pylori SS1 strain were analyzed by qPCR and FACS analysis. In vitro, bone marrow-derived DC on day 6 from CCR2KO and Wt mice cocultured with or without H. pylori were examined to determine the impact of CCR2 signaling on dendritic cells function by qPCR, ELISA, and FACS analyses. RESULTS: Acute H. pylori infection was associated with a threefold increase in CCR2 mRNA expression in the gastric mucosa. H. pylori-infected CCR2KO mice exhibited a higher degree of mucosal inflammation, that is, increased gastritis scores and pro-inflammatory cytokine mRNA levels, but lower degree of H. pylori gastric colonization compared to infected Wt mice. Peripheral H. pylori-specific immune response measured in the CCR2KO spleen was characterized by a higher Th17 response and a lower Treg response. In vitro, CCR2KO bone marrow-derived DC was less mature and shown a lower Treg/Th17 ratio. Moreover, blockade of CCR2 signaling by MCP-1 neutralizing antibody inhibited H. pylori-stimulated bone marrow-derived DC maturation. CONCLUSIONS: Our results indicate that CCR2 plays an essential role in H. pylori-induced immune tolerance and shed light on a novel mechanism of CCR2-dependent DC Treg induction, which appears to be important in maintaining mucosal homeostasis during H. pylori infection.