The prevalence of intestinal dysbiosis in patients referred for antireflux surgery

Intestinal Dysbiosis: Exploring Definition, Associated Symptoms, and Perspectives for a Comprehensive Understanding - a Scoping Review

Dysbiosis is a clinical condition marked by altered gut microbiota resulting from external and internal host factors. It is strongly associated with gastrointestinal and extraintestinal alterations, so its symptomatology is broad and nonspecific. To date, gaps remain that limit professionals from making a timely diagnosis and prescribing the appropriate treatment. We aim to synthesize existing literature regarding clinical parameters for the early detection of patients with intestinal dysbiosis and the clinical events in which the use of probiotics as adjuvant therapy is most frequently reported. A scoping review of the literature was conducted in PubMed, Embase, Cochrane, and BVS (Biblioteca Virtual en Salud in Spanish) databases for articles published in the last 5 years. Primary studies and literature reviews related to clinical presentation, dysbiosis screening, and probiotics as adjuvant therapy for adult and pediatric patients were included. Twenty-three articles were retrieved in which the most frequently reported symptoms were abdominal distension, abdominal pain, and diarrhea. Chronic and metabolic diseases where the conditions most strongly associated with dysbiosis. Depending on symptomatology and etiology, dysbiosis is often treated with probiotics. Dysbiosis, often linked to diarrhea, should be considered with other symptoms like abdominal distension and pain, along with predisposing conditions and patient risk factors. Probiotics are commonly used as co-adjuvant treatments for antibiotic-associated diarrhea, irritable bowel syndrome, and childhood allergic diseases. The most commonly used probiotics were Weizmannia coagulans (formerly B. coagulans), Alkalihalobacillus clausii (formerly Bacillus clausii), Lacticaseibacillus rhamnosus, Limosilactobacillus reuteri, and Saccharomyces boulardii.

Treatment of oesophageal and laryngo-pharyngeal symptoms of reflux in patients diagnosed with SIBO and IMO with antibiotics

Gastro-oesophageal reflux disease (GERD) may present with esophageal and/or extra-oesophageal, laryngo-pharyngeal (LPR) symptoms including cough, throat clearing and dysphonia. A definitive diagnosis can be challenging, and existing treatments are often ineffective in resolving them. Oesophageal symptoms thought to be caused by GERD can overlap with those from functional dyspepsia (FD) and previous studies have proposed intestinal dysbiosis such as small intestinal bacteria overgrowth (SIBO) and intestinal methogenic overgrowth (IMO) as potential causes. This study aims to establish the relationship between SIBO/IMO and LPR symptoms, and if their treatment improves LPR symptoms. We performed a retrospective cohort study of patients with SIBO or IMO in a high-volume, tertiary referral center for anti-reflux procedures between 2018 and 2023. The primary outcome measures were GERD-HQRL and LPR/RSI scores after treatment for SIBO/IMO, and anti-reflux medication use. Twenty-three patients were eligible. The mean decrease in GERD-HQRL score was 11.8 (3.31) (P = 0.0017). The mean decrease in RSI score was 8.57 (1.97) (P = 0.0003). In patients with raised DeMeester scores, the GERD-HQRL scores improved by 17.2 (5.02) (P = 0.009) and RSI scores by 9.33 (3.60) (P = 0.03). The symptom association probability was highest at 72.7% (n = 8) for belching; followed by 80% for heartburn (n = 4) and 66.7% for regurgitation (n = 4). The use of PPIs decreased in 95% (n = 19) of patients; 18 had stopped PPIs completely. All patients avoided potential surgical interventions. The diagnosis and treatment of SIBO in patients with atypical reflux symptoms may prevent unnecessary surgical and pharmacological treatments. Further prospective work is required to confirm this.

Symptom Profile of Patients With Intestinal Methanogen Overgrowth: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Archaea constitute one of the main 3 domains of the tree of life, distinct from eukaryotes and bacteria. Excessive luminal loads of methanogenic archaea (intestinal methanogen overgrowth [IMO]) have been implicated in the pathophysiology of various diseases, including constipation. To elucidate the phenotypical presentation of IMO, we performed a systematic review and meta-analysis of the prevalence and severity of gastrointestinal symptoms in subjects with IMO as compared with subjects without IMO.

METHODS

Electronic databases, including OVID MEDLINE and Cochrane Database from inception until September 2023, were systematically searched. Prevalence rates, odds ratios (ORs), standardized mean difference (SMD), and 95% confidence intervals (CIs) of symptoms were calculated.

RESULTS

Nineteen studies were included (1293 patients with IMO and 3208 controls). Patients with IMO exhibited various gastrointestinal symptoms, including bloating (78%), constipation (51%), diarrhea (33%), abdominal pain (65%), nausea (30%), and flatulence (56%). Patients with IMO had a significantly higher prevalence of constipation as compared with controls (47% vs 38%; OR, 2.04; 95% CI, 1.48-2.83; P < .0001) along with lower prevalence of diarrhea (37% vs 52%; OR, 0.58; 95% CI, 0.37-0.90; P = .01) and nausea (32% vs 45%; OR, 0.75; 95% CI, 0.60-0.94; P = .01). Patients with IMO had higher severity of constipation (SMD, 0.77; 95% CI, 0.11-1.43; P = .02) and lower severity of diarrhea (SMD, -0.71; 95% CI, -1.39 to -0.03; P = .04). Significant heterogeneity was detected.

CONCLUSION

Patients with IMO exhibit a higher rate and severity of constipation along with lower rate and severity of diarrhea. The distinct phenotype of patients with IMO should be incorporated in patient-reported outcome measures and further correlated with mechanistic microbiome studies.

Microbiota gut-brain axis: implications for pediatric-onset leukodystrophies

Neurodegenerative disorders are a group of diseases characterized by progressive degeneration of the nervous system, leading to a gradual loss of previously acquired motor, sensory and/or cognitive functions. Leukodystrophies are amongst the most frequent childhood-onset neurodegenerative diseases and primarily affect the white matter of the brain, often resulting in neuro-motor disability. Notably, gastrointestinal (GI) symptoms and complications, such as gastroesophageal reflux disease (GERD) and dysphagia, significantly impact patients' quality of life, highlighting the need for comprehensive management strategies. Gut dysbiosis, characterized by microbial imbalance, has been implicated in various GI disorders and neurodegenerative diseases. This narrative review explores the intricate relationship between GI symptoms, Gut Microbiota (GM), and neurodegeneration. Emerging evidence underscores the profound influence of GM on neurological functions via the microbiota gut-brain axis. Animal models have demonstrated alterations in GM composition associated with neuroinflammation and neurodegeneration. Our single-centre experience reveals a high prevalence of GI symptoms in leukodystrophy population, emphasizing the importance of gastroenterological assessment and nutritional intervention in affected children. The bidirectional relationship between GI disorders and neurodegeneration suggests a potential role of gut dysbiosis in disease progression. Prospective studies investigating the GM in leukodystrophies are essential to understand the role of gut-brain axis dysfunction in disease progression and identify novel therapeutic targets. In conclusion, elucidating the interplay between GI disorders, GM, and neurodegeneration holds promise for precision treatments aimed at improving patient outcomes and quality of life.

The Lactulose Breath Test Can Predict Refractory Gastroesophageal Reflux Disease by Measuring Bacterial Overgrowth in the Small Intestine

OBJECTIVE

The diagnosis of RGERD in patients typically involves 24-hour esophageal pH monitoring, but due to its invasiveness and low patient compliance, new screening methods are needed. In this study, a lactulose breath test (LBT) was conducted to detect the growth of small intestine bacteria (SIBO) and explore the potential relationship between LBT and RGERD to identify a new treatment method for RGERD.

METHODS

A total of 178 patients with gastroesophageal reflux were enrolled from June 2020 to December 2022 in the Gastroenterology Department, Building 3, the First Affiliated Hospital of Kunming Medical University; these patients included 96 patients with nonrefractory GERD (NRGERD) and 82 patients with RGERD. The Gerd Q score, reflux symptom index (RSI) score, gastroscopy results, clinical symptoms, and other related indicators were collected. Statistical methods were used to analyze the gathered data.

RESULTS

The incidence of acid reflux and heartburn in patients with RGERD was significantly greater than that in patients with NRGERD (67.10% vs. 42.70%, P<0.01 and 65.00% vs. 34.40%, P<0.01). The CH4 values of patients with RGERD were significantly greater than those of patients with NRGERD at each time point, and there was a correlation between the CH4 values at 60 min and RGERD (P<0.05). For patients with RGERD, the incidence of abdominal pain, acid regurgitation, and heartburn was greater in the CH4-positive group than in the CH4-negative group (61.90% vs. 57.50%, 69.05% vs. 65.00%, 69.05% vs. 57.50%, P>0.05). The incidence of nausea was also greater in the CH4-positive group than in the CH4-negative group (61.90% vs. 35.00%, P<0.05).

CONCLUSION

Increased CH4 levels are correlated with RGERD. In addition, patients with RGERD may develop SIBO after long-term use of PPIs, and interventions involving SIBO could provide new ideas for the treatment of RGERD.

Causal relationship between gut microbiota and risk of gastroesophageal reflux disease: a genetic correlation and bidirectional Mendelian randomization study

Background

Numerous observational studies have identified a linkage between the gut microbiota and gastroesophageal reflux disease (GERD). However, a clear causative association between the gut microbiota and GERD has yet to be definitively ascertained, given the presence of confounding variables.

Methods

The genome-wide association study (GWAS) pertaining to the microbiome, conducted by the MiBioGen consortium and comprising 18,340 samples from 24 population-based cohorts, served as the exposure dataset. Summary-level data for GERD were obtained from a recent publicly available genome-wide association involving 78 707 GERD cases and 288 734 controls of European descent. The inverse variance-weighted (IVW) method was performed as a primary analysis, the other four methods were used as supporting analyses. Furthermore, sensitivity analyses encompassing Cochran's Q statistics, MR-Egger intercept, MR-PRESSO global test, and leave-one-out methodology were carried out to identify potential heterogeneity and horizontal pleiotropy. Ultimately, a reverse MR assessment was conducted to investigate the potential for reverse causation.

Results

The IVW method's findings suggested protective roles against GERD for the Family Clostridiales Vadin BB60 group (P = 0.027), Genus Lachnospiraceae UCG004 (P = 0.026), Genus Methanobrevibacter (P = 0.026), and Phylum Actinobacteria (P = 0.019). In contrast, Class Mollicutes (P = 0.037), Genus Anaerostipes (P = 0.049), and Phylum Tenericutes (P = 0.024) emerged as potential GERD risk factors. In assessing reverse causation with GERD as the exposure and gut microbiota as the outcome, the findings indicate that GERD leads to dysbiosis in 13 distinct gut microbiota classes. The MR results' reliability was confirmed by thorough assessments of heterogeneity and pleiotropy.

Conclusions

For the first time, the MR analysis indicates a genetic link between gut microbiota abundance changes and GERD risk. This not only substantiates the potential of intestinal microecological therapy for GERD, but also establishes a basis for advanced research into the role of intestinal microbiota in the etiology of GERD.

Prevalence and severity of abdominal bloating in patients with gastroesophageal reflux disease

Abdominal bloating (AB) is a common symptom among patients with gastroesophageal reflux disease (GERD); however, in clinical practice, its prevalence is likely underestimated due to the lack of objective tools to measure its frequency and severity. It is associated with dissatisfaction and worse quality of life, but data on its prevalence before and after mechanical control of GERD (i.e. fundoplication, magnetic sphincter augmentation, and antireflux mucosectomy) are lacking. To assess and determine the pre- and postoperative prevalence and severity of AB among patients with GERD, we conducted a structured literature search using MeSH and free-text terms in MEDLINE (via Pubmed), EMBASE, and Taylor & Francis Online between January 1977 and October 2022. Fifteen articles reporting the prevalence or severity of AB using quality-of-life questionnaires before or after antireflux surgery (ARS) were included. Overall, a high prevalence of AB before ARS was found. A decline in the prevalence and severity of AB was documented postoperatively in most cases independent of the surgical approach. Among surgical approaches, a complete fundoplication had the highest reported postoperative AB. Overall, patients reported less severe and less frequent AB after ARS than before. The traditional belief that postoperative bloating is a sequela of ARS should be reevaluated.

Efficacy of Atezolizumab in Patients With Advanced NSCLC Receiving Concomitant Antibiotic or Proton Pump Inhibitor Treatment: Pooled Analysis of Five Randomized Control Trials

INTRODUCTION

Gut dysbiosis may reduce immune checkpoint inhibitor (ICI) efficacy. Antibiotics and proton pump inhibitors (PPIs) are commonly used drugs causing gut dysbiosis. There is limited randomized controlled trial (RCT) evidence on whether antibiotics or PPIs impact ICI benefit versus comparator treatments.

METHODS

This study pooled five RCTs (IMpower130, IMpower131, IMpower150, OAK, and POPLAR) evaluating atezolizumab in advanced NSCLC. Atezolizumab efficacy (hazard ratio with 95% confidence intervals) was assessed for subgroups on the basis of antibiotic and PPI use at randomization. The association between antibiotic and PPI use with pretreatment peripheral blood immunophenotype was also explored.

RESULTS

Of 4458 participants, 285 received an antibiotic in the 30-day pretreatment and 1225 were using a PPI at treatment initiation. Overall survival efficacy of atezolizumab was similar (p[interaction] = 0.35) for antibiotic users (hazard ratio 95% confidence interval: 0.73 [0.53-0.99]) and antibiotic nonusers (0.82 [0.74-0.91]). Nevertheless, efficacy was reduced (p[interaction] = 0.003) for PPI users (1.00 [0.85-1.17]) compared with PPI nonusers (0.76 [0.69-0.83]). Findings were consistent across RCTs and for progression-free survival. PPI use was associated with 9%, 18%, and 9% lower counts of lymphocytes, CD19+, and CD16+CD56+ immune cells, respectively (p < 0·01).

CONCLUSIONS

Reassuringly, atezolizumab efficacy did not differ for antibiotic users. Opposingly, PPI use was consistently associated with decreased atezolizumab efficacy and lower pretreatment counts of lymphocytes, CD19+, and CD16+CD56+ immune cells. Given that approximately 30% of patients with cancer use PPIs, there is an urgent need for evidence on the impacts of PPIs on other ICIs and for the development of guidelines on nonessential PPI use with ICIs.