Intestinal microbiota in functional bowel disorders: a Rome foundation report

Genetic Variants in Carbohydrate Digestive Enzyme and Transport Genes Associated with Risk of Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is characterized by abdominal pain and alterations in bowel pattern, such as constipation (IBS-C), diarrhea (IBS-D), or mixed (IBS-M). Since malabsorption of ingested carbohydrates (CHO) can cause abdominal symptoms that closely mimic those of IBS, identifying genetic mutations in CHO digestive enzymes associated with IBS symptoms is critical to ascertain IBS pathophysiology. Through candidate gene association studies, we identify several common variants in TREH, SI, SLC5A1 and SLC2A5 that are associated with IBS symptoms. By investigating rare recessive Mendelian or oligogenic inheritance patterns, we identify case-exclusive rare deleterious variation in known disease genes (SI, LCT, ALDOB, and SLC5A1) as well as candidate disease genes (MGAM and SLC5A2), providing potential evidence of monogenic or oligogenic inheritance in a subset of IBS cases. Finally, our data highlight that moderate to severe IBS-associated gastrointestinal symptoms are often observed in IBS cases carrying one or more of deleterious rare variants.

The Role of Bovine Kappa-Casein Glycomacropeptide in Modulating the Microbiome and Inflammatory Responses of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder marked by chronic abdominal pain, bloating, and irregular bowel habits. Effective treatments are still actively sought. Kappa-casein glycomacropeptide (GMP), a milk-derived peptide, holds promise because it can modulate the gut microbiome, immune responses, gut motility, and barrier functions, as well as binding toxins. These properties align with the recognized pathophysiological aspects of IBS, including gut microbiota imbalances, immune system dysregulation, and altered gut barrier functions. This review delves into GMP's role in regulating the gut microbiome, accentuating its influence on bacterial populations and its potential to promote beneficial bacteria while inhibiting pathogenic varieties. It further investigates the gut microbial shifts observed in IBS patients and contemplates GMP's potential for restoring microbial equilibrium and overall gut health. The anti-inflammatory attributes of GMP, especially its impact on vital inflammatory markers and capacity to temper the low-grade inflammation present in IBS are also discussed. In addition, this review delves into current research on GMP's effects on gut motility and barrier integrity and examines the changes in gut motility and barrier function observed in IBS sufferers. The overarching goal is to assess the potential clinical utility of GMP in IBS management.

Diagnosis of Irritable Bowel Syndrome: Primary Care Physicians Compared with Gastroenterologists

Objective: To examine disparities between primary care provider (PCP) and gastroenterologist diagnosis and management of irritable bowel syndrome (IBS).Design: Retrospective cross-sectional study.Setting: A 547-bed quaternary-care hospital within the Loyola University Healthcare System.Participants: 1000 patients aged 18-65 with an ICD-10 diagnosis of IBSMethods: We randomly selected 1000 patients aged 18 to 65 years within the Loyola University Healthcare System's electronic medical record with an ICD-10 diagnosis of IBS. Physician notes and diagnostic results were reviewed for documentation of symptoms fulfilling Rome IV criteria and resolution of symptoms. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of primary diagnoses assigned by PCPs and gastroenterologists were assessed along with number of diagnostic tests ordered.Results: The mean age (SD) was 45 (12) years, and 76.9% were female. Sensitivity of an IBS diagnosis by a PCP was 77.6% (95% CI 73.3-81.9), compared with 60.1% (95% CI 54.7-65.6) for a gastroenterologist. Specificity of an IBS diagnosis by a PCP was 27.5% (95% CI 23.5-31.5), compared with 71.1% (95% CI 64.6-77.5) for a gastroenterologist diagnosis of IBS. A gastroenterologist diagnosis of IBS carried a high PPV (77.3%, 95% CI 72.0-82.6) compared with 44.6% (95% CI 40.7-48.5) for a PCP. Of 180 patients with outcome data, 69.4% had resolution of symptoms at follow-up.Conclusion: The sensitivity of gastroenterologist diagnosis of IBS closely matches the sensitivity of Rome IV criteria in validation studies. The high specificity and PPV of gastroenterologists suggest more cautious diagnosis by gastroenterologists, with PCPs more likely to assign a diagnosis of IBS incorrectly or without sufficient documentation of symptoms fulfilling Rome IV criteria. Reported resolution rates suggest primary care management of IBS is appropriate, but PCPs may benefit from gastroenterologist consultation and diagnostic guidelines for greater specificity in diagnosing IBS.

Unraveling mechanistic insights into the role of microbiome in neurogenic hypertension: A comprehensive review

Neurogenic hypertension, a complex and multifactorial cardiovascular disorder, is known to be influenced by various genetic, environmental, and lifestyle factors. In recent years, there has been growing interest in the role of the gut microbiome in hypertension pathogenesis. The bidirectional communication between the gut microbiota and the central nervous system, known as the microbiota-gut-brain axis, has emerged as a crucial mechanism through which the gut microbiota exerts its influence on neuroinflammation, immune responses, and blood pressure regulation. Recent studies have shown how the microbiome has a substantial impact on a variety of physiological functions, such as cardiovascular health. The increased sympathetic activity to the gut may cause microbial dysbiosis, increased permeability of the gut, and increased inflammatory reactions by altering a number of intestinal bacteria producing short-chain fatty acids (SCFAs) and the concentrations of lipopolysaccharide (LPS) in the plasma. Collectively, these microbial metabolic and structural compounds stimulate sympathetic stimulation, which may be an important stage in the onset of hypertension. The result is an upsurge in peripheral and central inflammatory response. In addition, it has recently been shown that a link between the immune system and the gut microbiota might play a significant role in hypertension. The therapeutic implications of the gut microbiome including probiotic usage, prebiotics, dietary modifications, and fecal microbiota transplantation in neurogenic hypertension have also been found. A large body of research suggests that probiotic supplementation might help reduce chronic inflammation and hypertension that have an association with dysbiosis in the gut microbiota. Overall, this review sheds light on the intricate interplay between the gut microbiome and neurogenic hypertension, providing valuable insights for both researchers and clinicians. As our knowledge of the microbiome's role in hypertension expands, novel therapeutic strategies and diagnostic biomarkers may pave the way for more effective management and prevention of this prevalent cardiovascular disorder. Exploring the potential of the microbiome in hypertension offers an exciting avenue for future research and offers opportunities for precision medicine and improved patient care.

Efficacy and safety of human gut-derived multi-strain probiotics in patients with irritable bowel syndrome: A prospective open-label observation study

This study aimed to investigate the efficacy and safety of human gut-derived multi-strain probiotics in patients with irritable bowel syndrome (IBS). This was an open-label, prospective, observational study. Patients with IBS were administered human gut-derived multi-strain probiotics for 4 weeks. The primary and secondary outcomes were based on the overall responder rate of the total IBS severity scoring system (IBS-SSS) score (>50-point decrease) and the IBS quality of life (IBS-QOL) score and IBS-SSS1 subscore (>10-point decrease in both scores), respectively. The estimated response rate is 55%. Of 44 patients, the total IBS-SSS score responder rate was 18.2% and 63.6% of patients at 2 and 4 weeks, respectively (P = .018). Compared with baseline, a significant improvement in the IBS-QOL score was observed in 27.3% and 63.6% of patients at 2 and 4 weeks, respectively (P = .001). Overall improvement rates in the IBS-SSS1 subscore were observed in 29.5% and 61.4% of patients at 2 and 4 weeks, respectively (P < .001). Primary and secondary outcomes were higher at 4 weeks (total IBS-SSS score, 63.6%; IBS-QOL score, 63.6%; IBS-SSS1 subscore, 61.4%) than the estimated responder rate (55%). Human gut-derived multi-strain probiotics have the potential to become an effective and safe treatment option for IBS patients.

Global trends and hotspots of gastrointestinal microbiome and toxicity based on bibliometrics

BACKGROUND

Toxicity concerns persist in the fields of public health, environmental science, and pharmacology. The intricate and vital role of the gastrointestinal microbiome in influencing toxicity and overall human health has gained increasing recognition in recent years. This study presents a comprehensive bibliometric analysis to evaluate the global scientific output, emerging trends, and research focal points in the area of gastrointestinal microbiome and toxicity.

METHODS

The Web of Science Core Collection database was retrieved for publications on the gastrointestinal microbiome and toxicity from 1980 to 2022. Our analysis included scholarly research papers written in English and excluded duplicate publications. We used Biblioshiny and R to summarize the count and citation metrics of included articles, and visualized research trends and keywords. CiteSpace was used to identify reference literature, keywords, and citation bursts. VOSviewer was used to visualize the network of related countries, institutions, authors, co-cited authors, and keywords.

RESULTS

A total of 2,140 articles were included, allowing us to identify significant countries, institutions, authors, and research focal points. Our results indicate a growing trend in the field, with China and the United States leading the research. The most productive journal in this area is Science of the Total Environment. Key findings revealed that research hotspots have shifted from drugs to environmental pollutants, emphasizing microplastics. Important mechanisms studied include oxidative stress, metabolism, inflammation, and apoptosis, with target organs being the gastrointestinal tract, liver, and brain. Furthermore, we highlight the rising significance of the gut-brain axis and the usage of zebrafish as a model organism.

CONCLUSION

Despite certain limitations, such as focusing solely on English-language publications and excluding unpublished literature, our findings provide valuable insights into the current state of research on toxicity and the gastrointestinal microbiome. In the future, modifications to the gastrointestinal microbiome could offer new directions for treating and mitigating toxicity. These discoveries provide a comprehensive perspective on the broader scope of this research field.

Efficacy and dose response of Lactiplantibacillus plantarum in diarrhea-predominant irritable bowel syndrome

BACKGROUND

Probiotics have shown promise in alleviating symptoms of diarrhea-predominant irritable bowel syndrome (IBS-D); however, the certainty of evidence is low. Well-powered randomized controlled dose-ranging trials are warranted on promising single-strain candidates.

AIM

To investigate the clinical efficacy of Lactiplantibacillus plantarum (L. plantarum) Lpla33 (DSM34428) in adults with IBS-D.

METHODS

This is a randomized, double-blind, placebo-controlled, multi-center, and dose-ranging study. Three hundred and seven adults, 18-70 years of age, with IBS-D, according to Rome IV criteria, were allocated (1:1:1) to receive placebo or L. plantarum Lpla33 at 1 × 109 (1B) or 1 × 1010 (10B) colony-forming units/d over an 8-wk intervention period. The primary outcome was the change in IBS severity scoring system (IBS-SSS) total score after 8 wk, while secondary and exploratory outcomes included abdominal pain severity, IBS related quality of life, stool and microbial profile, and perceived stress.

RESULTS

IBS-SSS was significantly reduced, after 8 wk, in participants receiving L. plantarum 1B (-128.45 ± 83.30; P < 0.001) and L. plantarum 10B (-156.77 ± 99.06; P < 0.001), compared to placebo (-58.82 ± 74.75). Further, a dose-ranging effect was observed, with a greater absolute reduction in the L. plantarum 10B group (P < 0.05). A reduction in sub-scores related to abdominal pain, abdominal distension, bowel habits, and quality of life was observed in both L. plantarum groups compared to placebo (P < 0.001). Further, 62.5% and 88.4% of participants administered L. plantarum 1B and 10B, respectively, were classified as stool consistency responders based on a reduction in diarrheal stool form, as compared to 26.3% in the placebo group (P < 0.001). In contrast, no significant shifts were observed in microbial diversity.

CONCLUSION

L. plantarum Lpla33 (DSM34428) is well tolerated and improves IBS symptom severity with a dose-ranging effect and a corresponding normalization of bowel habits in adults with IBS-D.

Nutritional Interventions with Bacillus coagulans Improved Glucose Metabolism and Hyperinsulinemia in Mice with Acute Intermittent Porphyria

Acute intermittent porphyria (AIP) is a metabolic disorder caused by mutations in the porphobilinogen deaminase (PBGD) gene, encoding the third enzyme of the heme synthesis pathway. Although AIP is characterized by low clinical penetrance (~1% of PBGD mutation carriers), patients with clinically stable disease report chronic symptoms and frequently show insulin resistance. This study aimed to evaluate the beneficial impact of nutritional interventions on correct carbohydrate dysfunctions in a mouse model of AIP that reproduces insulin resistance and altered glucose metabolism. The addition of spores of Bacillus coagulans in drinking water for 12 weeks modified the gut microbiome composition in AIP mice, ameliorated glucose tolerance and hyperinsulinemia, and stimulated fat disposal in adipose tissue. Lipid breakdown may be mediated by muscles burning energy and heat dissipation by brown adipose tissue, resulting in a loss of fatty tissue and improved lean/fat tissue ratio. Probiotic supplementation also improved muscle glucose uptake, as measured using Positron Emission Tomography (PET) analysis. In conclusion, these data provide a proof of concept that probiotics, as a dietary intervention in AIP, induce relevant changes in intestinal bacteria composition and improve glucose uptake and muscular energy utilization. Probiotics may offer a safe, efficient, and cost-effective option to manage people with insulin resistance associated with AIP.

Probiotics Alleviate Chemotherapy-Associated Intestinal Mucosal Injury via the TLR4-NFκB Signaling Pathway

Introduction

Temozolomide (TMZ) induces intestinal mucosa injury that cannot be fully counteracted by supportive treatment. Probiotics regulate gut microbial composition and the host immune system and may alleviate this side effect. We aimed to investigate the potential and mechanism of Lactobacillus rhamnosus GG (LGG) in relieving intestinal mucosal injury induced by TMZ.

Methods

Glioblastoma mice were divided into four groups: CON (control), LGG (10⁹ CFU/mL, treated for 7 days), TMZ (50 mg/kg·d, treated for 5 days), LGG+TMZ (LGG for 7 days and TMZ subsequently for 5 days). Body weight, food intake, and fecal pH were recorded. Intestinal tissue samples were collected 1 day after the end of TMZ treatment. Degree of damage to intestine, expression of IL1β, IL6, TNFα, and IL10 in jejunum were determined. Levels of tight-junction proteins (ZO1, occludin), TLR4, IKKβ, IκBα, and P65 with their phosphorylation in jejunum were measured.

Results

Decreases in body weight, food intake, spleen index in the TMZ group were mitigated in the LGG+TMZ group, and the degree of intestinal shortening and damage to jejunum villus were also alleviated. The expression of tight-junction proteins in the LGG+TMZ group was significantly greater than that in the TMZ group. IκBα in intestinal tissue significantly decreased in the TMZ group, phos-IKKβ and phos-P65 increased compared to the CON group, and LGG reversed such changes in IκBα and phos-P65 in the LGG+TMZ group. Intestinal inflammatory cytokines were significantly increased in the TMZ group, but lower in the LGG+TMZ group. Moreover, expression of TLR4 in LGG group was significantly lower than that in the CON group. LGG inhibited the rise of TLR4 after TMZ in the LGG+TMZ group compared to the TMZ group.

Conclusion

LGG inhibits the activation of the TLR4-NFκB pathway and alleviates intestinal mucosal inflammation induced by TMZ, thereby protect the jejunum villi and mucosal physical barrier.

Effect of a probiotic formula on gastrointestinal health, immune responses and metabolic health in adults with functional constipation or functional diarrhea

Objective

Our aim was to determine the efficacy of four-week probiotic supplementation on gastrointestinal health. The secondary objectives were to assess probiotic effects on immune reaction, as well as weight control and metabolic health.

Methods

We conducted two randomized sub-trials, respectively, among subjects who were diagnosed with functional constipation (FC) or functional diarrhea (FDr) according to the Rome IV criteria. In each sub-trial, 70 eligible Chinese adults were randomized to receive a multi-strain probiotic combination or a placebo. Gastrointestinal symptoms, defecation habits, stool characteristics, blood and fecal biochemistry markers, anthropometrics measures, stress-associated responses, and intestinal flora changes were assessed at baseline and after probiotics intervention.

Results

Four weeks of probiotic supplementation reduced overall gastrointestinal symptoms scores in FC participants (p < 0.0001). Their mean weekly stool frequency increased from 3.3 times to 6.2 times; immune response and inflammation markers improved with increases in serum IgA, IFN-γ and fecal sIgA, and decrease in hsCRP; most components of lipid profile were significantly ameliorated, with increases in HDL-C and reductions in TC and TG; body weight, body mass index and basal metabolic rate decreased following probiotics consumption. For FDr participants, probiotics consumption markedly reduced overall gastrointestinal symptom scores (p < 0.0001); decreased stool frequency by 3 times per week; increased IgA, IFN-γ, sIgA concentrations, while lowered hsCRP and IL-4 levels. Both FC and FDr participants had improvement in the scores of defecation habits, anxiety or depression, and perceived stress. Probiotics supplementation promoted the production of all three major short-chain fatty acids. No changes were observed in LDL-C, IgG, IgM, IL-8, IL-10 and motilin.

Conclusion

Supplementation with the probiotic formula over a four-week period could help relieving gastrointestinal symptoms, improving satisfaction with defecation habits, emotional state and immune response, and ameliorating dysbacteriosis in participants with FC or FDr. It also had beneficial effects on lipid metabolism and weight control for FC participants.

Comparison of DNA extraction methods for 16S rRNA gene sequencing in the analysis of the human gut microbiome

The gut microbiome is widely analyzed using high-throughput sequencing, such as 16S rRNA gene amplicon sequencing and shotgun metagenomic sequencing (SMS). DNA extraction is known to have a large impact on the metagenomic analyses. The aim of this study was to compare DNA extraction protocols for 16S sequencing. In that context, four commonly used DNA extraction methods were compared for the analysis of the gut microbiota. Commercial versions were evaluated against modified protocols using a stool preprocessing device (SPD, bioMérieux) upstream DNA extraction. Stool samples from nine healthy volunteers and nine patients with a Clostridium difficile infection were extracted with all protocols and 16S sequenced. Protocols were ranked using wet- and dry-lab criteria, including quality controls of the extracted genomic DNA, alpha-diversity, accuracy using a mock community of known composition and repeatability across technical replicates. SPD improved overall efficiency of three of the four tested protocols compared with their commercial version, in terms of DNA extraction yield, sample alpha-diversity, and recovery of Gram-positive bacteria. The best overall performance was obtained for the S-DQ protocol, SPD combined with the DNeasy PowerLyser PowerSoil protocol from QIAGEN. Based on this evaluation, we strongly believe that the use of such stool preprocessing device improves both the standardization and the quality of the DNA extraction in the human gut microbiome studies.

Signalling cognition: the gut microbiota and hypothalamic-pituitary-adrenal axis

Cognitive function in humans depends on the complex and interplay between multiple body systems, including the hypothalamic-pituitary-adrenal (HPA) axis. The gut microbiota, which vastly outnumbers human cells and has a genetic potential that exceeds that of the human genome, plays a crucial role in this interplay. The microbiota-gut-brain (MGB) axis is a bidirectional signalling pathway that operates through neural, endocrine, immune, and metabolic pathways. One of the major neuroendocrine systems responding to stress is the HPA axis which produces glucocorticoids such as cortisol in humans and corticosterone in rodents. Appropriate concentrations of cortisol are essential for normal neurodevelopment and function, as well as cognitive processes such as learning and memory, and studies have shown that microbes modulate the HPA axis throughout life. Stress can significantly impact the MGB axis via the HPA axis and other pathways. Animal research has advanced our understanding of these mechanisms and pathways, leading to a paradigm shift in conceptual thinking about the influence of the microbiota on human health and disease. Preclinical and human trials are currently underway to determine how these animal models translate to humans. In this review article, we summarize the current knowledge of the relationship between the gut microbiota, HPA axis, and cognition, and provide an overview of the main findings and conclusions in this broad field.

Integrating metabonomics and metagenomics sequencing to study the anti-liver fibrosis effects of palmatine in Corydalis saxicola Bunting

ETHNOPHARMACOLOGICAL RELEVANCE

Corydalis saxicola Bunting (CS), a traditional Chinese folk medicine, has been effectively used for treating liver disease in Zhuang nationality in South China. However, the main anti-liver fibrosis ingredients in CS are incompletely understood.

AIM OF THE STUDY

To elucidate the main anti-liver fibrosis ingredients in CS and its underlying mechanism.

MATERIAL AND METHODS

Firstly, spectrum-effect relationship (SER) strategy was applied to identify the major ingredients against liver fibrosis in CS. Subsequently, ¹H NMR metabonomics and metagenomics sequencing techniques were used to clarify the intervention of palmatine (PAL) on liver fibrosis. Furthermore, the expression of tight junction proteins and the levels of liver inflammation factors were examination, the effect of PAL on microbiota was verified by FMT.

RESULTS

The SER model revealed that PAL was the most important active ingredient in CS. ¹H NMR fecal metabonomics showed that PAL could reserve the abnormal levels of gut microbial-mediated metabolites of liver fibrosis, such as isoleucine, taurine, butyrate, propionate, lactate, glucose, which mainly involved in amino acid metabolism, intestinal flora metabolism and energy metabolism. Metagenomics sequencing found that PAL could callback the abundance of s__Lactobacillus_murinus, s__Lactobacillus_reuteri, s__Lactobacillus_johnsonii, s__Lactobacillus_acidophilus and s__Faecalibaculum_rodentium to varying degree. Furthermore, the intestinal barrier function and the levels of hepatic inflammation factors were significantly ameliorated by PAL. FMT demonstrated that the therapeutic efficiency of PAL was closely associated with gut microbiota.

CONCLUSION

The effects of CS on liver fibrosis were attributed in part to PAL by alleviating metabolic disorders and rebalancing gut microbiota. The SER strategy may be a useful method for the discovery of active constituents in natural plants.

Gut microbiota and irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that poses a significant health concern. Although its etiology remains unknown, there is growing evidence that gut dysbiosis is involved in the development and exacerbation of IBS. Previous studies have reported altered microbial diversity, abundance, and composition in IBS patients when compared to controls. However, whether dysbiosis or aberrant changes in the intestinal microbiota can be used as a hallmark of IBS remains inconclusive. We reviewed the literatures on changes in and roles of intestinal microbiota in relation to IBS and discussed various gut microbiota manipulation strategies. Gut microbiota may affect IBS development by regulating the mucosal immune system, brain-gut-microbiome interaction, and intestinal barrier function. The advent of high-throughput multi-omics provides important insights into the pathogenesis of IBS and promotes the development of individualized treatment for IBS. Despite advances in currently available microbiota-directed therapies, large-scale, well-organized, and long-term randomized controlled trials are highly warranted to assess their clinical effects. Overall, gut microbiota alterations play a critical role in the pathophysiology of IBS, and modulation of microbiota has a significant therapeutic potential that requires to be further verified.

Efficacy and safety of probiotics in the treatment of irritable bowel syndrome: A systematic review and meta-analysis of randomised clinical trials using ROME IV criteria

BACKGROUND

Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder which affects a great number of patients globally. Clinical trials and meta-analyses have evaluated different therapies for IBS. Some of them have shown that probiotics play a significant role in the management of IBS-patients. Nevertheless, results are controversial, and the efficacy of the administration of probiotics remains to be confirmed, especially in regard to which type of probiotic-strains are beneficial.

AIM

The aim of the present meta-analysis is to assess the efficacy and safety of the administration of probiotics to IBS-patients with a diagnosis based on Rome IV criteria, which is performed for the first time.

METHODS

Electronic databases (Pubmed, Scopus and Cochrane) were searched until 26.01.2023 for randomized controlled trials (RCTs) studying the administration of probiotics in adult IBS-patients, who were categorized according to the Rome IV criteria. The risk of bias was assessed using the Cochrane Risk of Bias tool (ROB) 2.0. Weighted and standardized mean difference with the 95% confidence intervals were used for the synthesis of the results. Primary outcomes were the decrease of IBS-Symptom Severity Score (IBS-SSS) and decrease of abdominal pain. The secondary outcomes were the improvement in quality of life (QoL) and the decrease of bloating. Lastly, the adverse effects of probiotics were evaluated. The protocol of the study has been registered at protocols.io (DOI dx.doi.org/10.17504/protocols.io.14egn218yg5d/v1).

RESULTS

Six double-blind (N = 970) placebo-control RCTs fulfilled the inclusion criteria and overall, nine different strains of probiotics were examined. No significant reduction in IBS-SSS (WMD -43.2, 95% CI -87.5 to 1.0, I2 = 82.9%) was demonstrated, whereas a significant decrease regarding abdominal pain (SMD -0.94, 95% CI -1.53 to -0.35, I2 = 92,2) was shown. Furthermore, no correlation between improvement of QoL and the use of probiotics (SMD -0.64, 95% CI -1.27 to 0.00, I2 = 93,9%) was shown. However, probiotics were associated with a significant reduction in bloating (SMD -0.28, 95% CI -0.47 to -0.09, I2 = 36,0%). A qualitative synthesis was conducted about adverse events and showed that the use of probiotics' is safe without severe adverse events.

CONCLUSIONS

The administration of probiotics to IBS-patients demonstrated a positive effect on pain and bloating, but due to significant heterogeneity and confounding factors, that were not examined in the included studies, a definitive statement cannot be made. Moreover, probiotics did not lead to an improvement in other parameters. There is a need for larger RCTs in IBS-patients diagnosed according to Rome IV (not III) criteria and especially it is essential to be conducted RCTs which examine the administration of specific strains and have similar methodological characteristics.

Intestinal Barrier Function in the Pathogenesis of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. The mechanisms involved in NAFLD onset are complicated and multifactorial. Recent literature has indicated that altered intestinal barrier function is related to the occurrence and progression of liver disease. The intestinal barrier is important for absorbing nutrients and electrolytes and for defending against toxins and antigens in the enteric environment. Major mechanisms by which the intestinal barrier influences the development of NAFLD involve the altered epithelial layer, decreased intracellular junction integrity, and increased intestinal barrier permeability. Increased intestinal permeability leads to luminal dysbiosis and allows the translocation of pathogenic bacteria and metabolites into the liver, inducing inflammation, immune response, and hepatocyte injury in NAFLD. Although research has been directed to NAFLD in recent decades, the pathophysiological changes in NAFLD initiation and progression are still not completely understood, and the therapeutic targets remain limited. A deeper understanding on the correlation between NAFLD pathogenesis and intestinal barrier regulation must be attained. Therefore, in this review, the components of the intestinal barrier and their respective functions and disruptions during the progression of NAFLD are discussed.

Otilonium Bromide Prevents Cholinergic Changes in the Distal Colon Induced by Chronic Water Avoidance Stress, a Rat Model of Irritable Bowel Syndrome

Irritable Bowel syndrome (IBS) is a highly widespread gastrointestinal disorder whose symptomatology mainly affect the large intestine. Among the risk factors, psychosocial stress is the most acknowledged. The repeated water avoidance stress (rWAS) is considered an animal model of psychosocial stress that is capable of mimicking IBS. Otilonium bromide (OB), which is orally administered, concentrates in the large bowel and controls most of the IBS symptoms in humans. Several reports have shown that OB has multiple mechanisms of action and cellular targets. We investigated whether the application of rWAS to rats induced morphological and functional alterations of the cholinergic neurotransmission in the distal colon and whether OB prevented them. The results demonstrated that rWAS affects cholinergic neurotransmission by causing an increase in acid mucin secretion, in the amplitude of electrically evoked contractile responses, abolished by atropine, and in the number of myenteric neurons expressing choline acetyltransferase. OB counteracted these changes and also showed an intrinsic antimuscarinic effect on the post-synaptic muscular receptors. We assume that the rWAS consequences on the cholinergic system are linked to corticotrophin-releasing factor-1 (CRF1) receptor activation by the CRF hypothalamic hormone. OB, by interfering with the CFR/CRFr activation, interrupted the cascade events responsible for the changes affecting the rWAS rat colon.

16S rRNA Gene Amplicon Sequencing of Gut Microbiota Affected by Four Probiotic Strains in Mice

Probiotics, also referred to as "living microorganisms," are mostly present in the genitals and the guts of animals. They can increase an animal's immunity, aid in digestion and absorption, control gut microbiota, protect against sickness, and even fight cancer. However, the differences in the effects of different types of probiotics on host gut microbiota composition are still unclear. In this study, 21-day-old specific pathogen-free (SPF) mice were gavaged with Lactobacillus acidophilus (La), Lactiplantibacillus plantarum (Lp), Bacillus subtilis (Bs), Enterococcus faecalis (Ef), LB broth medium, and MRS broth medium. We sequenced 16S rRNA from fecal samples from each group 14 d after gavaging. According to the results, there were significant differences among the six groups of samples in Firmicutes, Bacteroidetes, Proteobacteria, Bacteroidetes, Actinobacteria, and Desferribacter (p < 0.01) at the phylum level. Lactobacillus, Erysipelaceae Clostridium, Bacteroides, Brautella, Trichospiraceae Clostridium, Verummicroaceae Ruminococcus, Ruminococcus, Prevotella, Shigella, and Clostridium Clostridium differed significantly at the genus level (p < 0.01). Four kinds of probiotic changes in the composition and structure of the gut microbiota in mice were observed, but they did not cause changes in the diversity of the gut microbiota. In conclusion, the use of different probiotics resulted in different changes in the gut microbiota of the mice, including genera that some probiotics decreased and genera that some pathogens increased. According to the results of this study, different probiotic strains have different effects on the gut microbiota of mice, which may provide new ideas for the mechanism of action and application of microecological agents.

Ethanol Extract of Mao Jian Green Tea Attenuates Gastrointestinal Symptoms in a Rat Model of Irritable Bowel Syndrome with Constipation via the 5-hydroxytryptamine Signaling Pathway

In a previous study, we demonstrated that the hydro extract of Mao Jian Green Tea (MJGT) promotes gastrointestinal motility. In this study, the effect of MJGT ethanol extract (MJGT_EE) in treating irritable bowel syndrome with constipation (IBS-C) in a rat model constructed via maternal separation combined with an ice water stimulation was investigated. First, a successful model construction was confirmed through the determination of the fecal water content (FWC) and the smallest colorectal distension (CRD) volume. Then, the overall regulatory effects of MJGT_EE on the gastrointestinal tract were preliminarily evaluated through gastric emptying and small intestinal propulsion tests. Our findings indicated that MJGT_EE significantly increased FWC (p < 0.01) and the smallest CRD volume (p < 0.05) and promoted gastric emptying and small intestinal propulsion (p < 0.01). Furthermore, mechanistically, MJGT_EE reduced intestinal sensitivity by regulating the expression of proteins related to the serotonin (5-hydroxytryptamine; 5-HT) pathway. More specifically, it decreased tryptophan hydroxylase (TPH) expression (p < 0.05) and increased serotonin transporter (SERT) expression (p < 0.05), thereby decreasing 5-HT secretion (p < 0.01), activating the calmodulin (CaM)/myosin light chain kinase (MLCK) pathway, and increasing 5-HT₄ receptor (5-HT₄R) expression (p < 0.05). Moreover, MJGT_EE enhanced the diversity of gut microbiota, increased the proportion of beneficial bacteria, and regulated the number of 5-HT-related bacteria. Flavonoids may play the role of being active ingredients in MJGT_EE. These findings suggest that MJGT_EE could serve as a potential therapeutic pathway for IBS-C.

Food as Medicine: How to Influence the Microbiome and Improve Symptoms in Patients with Irritable Bowel Syndrome

PURPOSE OF REVIEW

This review highlights effects of dietary interventions on the gut microbiome and gastrointestinal symptoms in those with irritable bowel syndrome (IBS).

RECENT FINDINGS

It is hypothesized that gut dysbiosis factors into the pathophysiology of IBS. Various diets that influence the microbiome and intestinal physiology may have therapeutic properties. At present, data suggests that implementation of personalized dietary interventions have a mixed, but overall positive effect on the gut microbiome and IBS symptoms. The effect of dietary modification on the gut microbiome and GI symptoms in patients with IBS is a topic that has garnered interest due to the increasing prevalence of IBS and heightened awareness of the importance of gut health. The composition of the gut microbiome may be modulated by promoting fiber intake and implementation of exclusionary diets and dietary supplements; however, additional studies are needed to provide evidence-based guidelines in this patient population.

Interplay of Gut Microbiota in Polycystic Ovarian Syndrome: Role of Gut Microbiota, Mechanistic Pathways and Potential Treatment Strategies

Polycystic Ovarian Syndrome (PCOS) comprises a set of symptoms that pose significant risk factors for various diseases, including type 2 diabetes, cardiovascular disease, and cancer. Effective and safe methods to treat all the pathological symptoms of PCOS are not available. The gut microbiota has been shown to play an essential role in PCOS incidence and progression. Many dietary plants, prebiotics, and probiotics have been reported to ameliorate PCOS. Gut microbiota shows its effects in PCOS via a number of mechanistic pathways including maintenance of homeostasis, regulation of lipid and blood glucose levels. The effect of gut microbiota on PCOS has been widely reported in animal models but there are only a few reports of human studies. Increasing the diversity of gut microbiota, and up-regulating PCOS ameliorating gut microbiota are some of the ways through which prebiotics, probiotics, and polyphenols work. We present a comprehensive review on polyphenols from natural origin, probiotics, and fecal microbiota therapy that may be used to treat PCOS by modifying the gut microbiota.

Application and development of fecal microbiota transplantation in the treatment of gastrointestinal and metabolic diseases: A review

Fecal microbiota transplantation (FMT) restores a balanced intestinal flora, which helps to cure recurrent Clostridium difficile infections (RCDI). FMT has also been used to treat other gastrointestinal diseases, including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and chronic constipation, as well as a variety of non-GI disorders. The purpose of this review is to discuss gut microbiota and FMT treatment of GI and non-GI diseases. An imbalanced gut microbiota is known to predispose one to Clostridium difficile infections (CDI), IBD, and IBS. However, the complex role of the gut microbiota in maintaining health is a newer concept that is being increasingly studied. The microbiome plays a major role in cellular immunity and metabolism and has been implicated in the pathogenesis of non-GI autoimmune diseases, chronic fatigue syndrome, obesity, and even some neuropsychiatric disorders. Many recent studies have reported that viral gastroenteritis can affect intestinal epithelial cells, and SARS-CoV-2 virus has been identified in the stool of infected patients. FMT is a highly effective cure for RCDI, but a better understanding of the gut microbiota in maintaining health and controlled studies of FMT in a variety of conditions are needed before FMT can be accepted and used clinically.

Impact of Saccharomyces boulardii CNCM I-745 on Bacterial Overgrowth and Composition of Intestinal Microbiota in Diarrhea-Predominant Irritable Bowel Syndrome Patients: Results of a Randomized Pilot Study

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is associated with diarrhea-predominant irritable bowel syndrome (IBS-D). Probiotics like Saccharomyces boulardii CNCM I-745 (Sb) may be efficacious in balancing the microbiota. This randomized open label study assessed the effect of Sb in patients with bacterial overgrowth associated with IBS-D and its impact on the intestinal microbiota.

METHODS

Patients were randomized to receive Sb + dietary advice (Sb + DA) or dietary advice (DA) only for 15 days. SIBO was assessed by the lactulose hydrogen breath test (LHBT). Symptoms were assessed with the IBS Symptom Severity Scale (IBS-SSS) and stool consistency with the Bristol Stool Form Scale. Microbiota and mycobiota were analyzed by 16S rDNA and ITS2.

RESULTS

54 patients were included, among whom 48 (27 Sb + DA, 21 DA) were evaluated. Decrease of hydrogen excretion was slightly higher in Sb + DA group, 41% versus 29% in DA group, and IBS-SSS total score were reduced by -134 and -93, respectively. The proportion of patients with diarrhea was lower in the Sb + DA group than in the DA group (25.9% compared to 47.6%). Bacterial and fungal microbiota showed that Sb treatment was associated with several modifications. Interestingly, F. prausnitzii was more abundant in Sb-treated patients with marked clinical improvement. The safety of S. boulardii CNCM I-745 was excellent.

CONCLUSIONS

In patients with SIBO, S. boulardii CNCM I-745 associated with dietary advice reduced bacterial overgrowth and improved digestive symptoms while restoring the intestinal microbiota. The increased abundance of F. prausnitzii coupled with symptom improvement merits further research.

Cystic Fibrosis-Related Gut Dysbiosis: A Systematic Review

BACKGROUND AND AIMS

Cystic Fibrosis (CF) is associated with gut dysbiosis, local and systemic inflammation, and impaired immune function. Gut microbiota dysbiosis results from changes in the complex gut milieu in response to CF transmembrane conductance regulator (CFTR) dysfunction, pancreatic malabsorption, diet, medications, and environmental influences. In several diseases, alteration of the gut microbiota influences local and systemic inflammation and disease outcomes. We conducted a systematic review of the gut microbiota in CF and explored factors influencing dysbiosis.

METHODS

An electronic search of three databases was conducted in January 2019, and re-run in June 2021. Human, animal, and in vitro studies were included. The primary outcome was differences in the gut microbiota between people with CF (pwCF) and healthy controls. Secondary outcomes included the relationship between the gut microbiota and other factors, including diet, medication, inflammation, and pulmonary function in pwCF.

RESULTS

Thirty-eight studies were identified. The literature confirmed the presence of CF-related gut dysbiosis, characterized by reduced diversity and several taxonomic changes. There was a relative increase of bacteria associated with a pro-inflammatory response coupled with a reduction of those considered anti-inflammatory. However, studies linking gut dysbiosis to systemic and lung inflammation were limited. Causes of gut dysbiosis were multifactorial, and findings were variable. Data on the impact of CFTR modulators on the gut microbiota were limited.

CONCLUSIONS

CF-related gut dysbiosis is evident in pwCF. Whether this influences local and systemic disease and is amenable to interventions with diet and drugs, such as CFTR modulators, requires further investigation.

Aging is Associated With Constipation in Japanese Patients With Ulcerative Colitis: A Post Hoc Analysis

Aim: Age is a risk factor for constipation. Constipation is common in patients with ulcerative colitis (UC) and has been positively associated with disease activity, but evidence is limited. This study aimed to assess the association between disease activity and constipation in patients with UC. Methods: The study subjects consisted of 290 Japanese UC patients. The definition of constipation was based on Rome I criteria and/or medication for constipation. Information on and lifestyle habits was obtained from a self-administered questionnaire. Mucosal healing (MH) was defined as Mayo endoscopic subscore 0. Clinical remission (CR) was defined as both the absence of rectal bleeding and no abnormally high stool frequency (<3 times per day). Results: The prevalence of constipation is not associated with MH, CR, duration of UC and disease extent of UC. The prevalence of constipation among age groups, <40, 40-49 years, 50-59 years, 60-69 years, and >70 years was 10.0%, 5.8%, 15.7%, 11.8%, and 25.6%, respectively. >70 years was independently and positively associated with the prevalence of constipation (adjusted odds ratio 3.64 [95% confidence interval 1.26, 10.95], p for trend: .001). Conclusions: Aging was independently and positively associated with the prevalence of constipation in UC.

Targeting the endocannabinoid system for the treatment of abdominal pain in irritable bowel syndrome

The management of visceral pain in patients with disorders of gut-brain interaction, notably irritable bowel syndrome, presents a considerable clinical challenge, with few available treatment options. Patients are increasingly using cannabis and cannabinoids to control abdominal pain. Cannabis acts on receptors of the endocannabinoid system, an endogenous system of lipid mediators that regulates gastrointestinal function and pain processing pathways in health and disease. The endocannabinoid system represents a logical molecular therapeutic target for the treatment of pain in irritable bowel syndrome. Here, we review the physiological and pathophysiological functions of the endocannabinoid system with a focus on the peripheral and central regulation of gastrointestinal function and visceral nociception. We address the use of cannabinoids in pain management, comparing them to other treatment modalities, including opioids and neuromodulators. Finally, we discuss emerging therapeutic candidates targeting the endocannabinoid system for the treatment of pain in irritable bowel syndrome.

Effect of Massa Medicata Fermentata on the intestinal flora of rats with functional dyspepsia

BACKGROUND

Massa Medicata Fermentata (MMF) is one of the most commonly used traditional fermented Chinese medicines. MMF is widely used for the treatment of digestive diseases such as dyspepsia and flatulence in traditional Chinese medicine (TCM). However, the therapeutic mechanism of MMF is not well understood.

METHOD

In this study, SD rats received 0.1% iodoacetamide either alone or in combination with water platform sleep deprivation to induce functional dyspepsia and were administered MMF (1 or 3 g/kg/d, ig), mosapride citrate (Mosa., 2 mg/kg/d, ig) or saline for 21 days. After treatment, the sucrose preferences and gastric emptying rates of the rats were assessed; HE staining was used to detect the pathological changes in the rat duodenum; ELISA kits were used to detect motilin (MTL) in the rat duodenum and the serum contents of Interferon-λ (IFN-λ), Interleukin 6 (IL-6), and Tumor Necrosis Factor-α (TNF-α). An approach based on 16S rDNA amplicon sequencing was utilized to explore the intestinal microflora in the colon contents of rats and the metabolism of the microflora to assess the potential mechanisms of MMF in ameliorating functional dyspepsia (FD). In addition, gas chromatography-mass spectrometry (GC/MS) was used to detect changes in short fatty acids (SCFAs) in the colon contents of rats.

RESULTS

MMF reduced the serum levels of TNF-α, and IFN-λ, improved the morphology of duodenal intestinal villi and ameliorated intestinal mucosal lamina propria injury in FD rats, and the sucrose preference increased and the gastric emptying rate decreased in FD rats. MMF alleviated intestinal microflora disturbance and exerted a regulatory effect on Bacteroidetes, Proteobacteria, and Firmicutes, reduced total SCAFs, Butyric Acid, Propionic acid-2-methyl, Butanoic Acid-3-methyl, and Hexanoic acid.

CONCLUSIONS

These results showed that the effect of MMF on the intestinal flora and its metabolites may provide a new treatment strategy for FD.

Randomised clinical trial: efficacy and safety of the live biotherapeutic product MRx1234 in patients with irritable bowel syndrome

BACKGROUND

MRx1234 is a live biotherapeutic product that contains a strain of Blautia hydrogenotrophica. It is in development for the treatment of irritable bowel syndrome (IBS).

AIMS

To assess the efficacy and safety of MRx1234 in patients with IBS with predominant constipation (IBS-C) or diarrhoea (IBS-D) METHODS: We conducted a multicentre, randomised, double-blind, placebo-controlled, phase 2 trial. Patients aged 18-70 years in two parallel cohorts (IBS-C; IBS-D) were randomised (1:1) to MRx1234 or placebo for 8 weeks. The primary efficacy endpoint was overall responder rate-a composite of improved bowel habit (IBS-C: stool frequency; IBS-D: stool consistency) and abdominal pain intensity-for ≥50% of the treatment period in each cohort. Statistical testing was at a one-sided 0.10 significance level.

RESULTS

Of 366 randomised patients (164 IBS-C; 202 IBS-D), 365 received any study medication (177 MRx1234, 188 placebo). Numerically, although not statistically significantly different, more patients who received MRx1234 than placebo were overall responders in the IBS-C (25.0% vs. 17.1%) and IBS-D (23.4% vs. 17.8%) cohorts. Similar results were observed in the additional combined cohort analysis (24.1% vs. 17.5%; p = 0.063). For the components of the primary endpoint, significantly more patients on MRx1234 than placebo reported improvement in bowel habit in the IBS-C, IBS-D and combined cohorts, while improvements in abdominal pain were observed in each cohort. The safety profile of MRx1234 was similar to placebo.

CONCLUSIONS

MRx1234 has the potential to become a novel, safe treatment option for patients with IBS-C or IBS-D, and for those who have mixed symptoms or transition between subtypes.

CLINICALTRIALS

gov #NCT03721107.

Lactobacillus gasseri LA806 Supplementation in Patients with Irritable Bowel Syndrome: A Multicenter Study

The potential benefits of Lactobacillus gasseri LA806 in IBS were previously identified in a comprehensive preclinical research program. The purpose of this multicenter study was to explore in real-life conditions changes in IBS symptoms and quality of life in patients receiving a 4-week supplementation with L. gasseri LA806. Altogether 119 patients meeting Rome IV criteria for IBS were included, of whom 118 received the supplement. The majority of patients (71.8% (95% CI 63.6−79.9%)) manifested a ≥30% decrease in abdominal pain at 4 weeks, the mean abdominal pain score diminishing by 54.2% (from 5.3 ± 2.2 to 2.2 ± 2.4, p < 0.0001). A statistically significant decrease in abdominal pain was seen as early as the first week. A decrease of ≥30% in both abdominal pain score and global IBS symptom score was attained in 61.5% of patients (95% CI 51.7−71.2%). The mean IBS-SSS score fell by 152 ± 112 points (p = 0.001), with symptoms being attenuated in 85% of patients (CGI-I). Supplementation led to a 10-fold decrease in the number of patients reporting severe IBS symptoms. The concomitant intake of antidiarrheals, antispasmodics and analgesics decreased and quality of life scores significantly improved. These preliminary results warrant confirmation by a randomized, placebo-controlled study that this study will allow a better design.

Dysbiosis of Fecal Microbiota in Tg2576 Mice for Alzheimer's Disease during Pathological Constipation

Tg2576 transgenic mice for Alzheimer's disease (AD) exhibited significant phenotypes for neuropathological constipation, but no research has been conducted on the association of the fecal microbiota with dysbiosis. The correlation between fecal microbiota composition and neuropathological constipation in Tg2576 mice was investigated by examining the profile of fecal microbiota and fecal microbiota transplantation (FMT) in 9-10-month-old Tg2576 mice with the AD phenotypes and constipation. Several constipation phenotypes, including stool parameters, colon length, and histopathological structures, were observed prominently in Tg2576 mice compared to the wild-type (WT) mice. The fecal microbiota of Tg2576 mice showed decreases in Bacteroidetes and increases in the Firmicutes and Proteobacteria populations at the phylum level. The FMT study showed that stool parameters, including weight, water content, and morphology, decreased remarkably in the FMT group transplanted with a fecal suspension of Tg2576 mice (TgFMT) compared to the FMT group transplanted with a fecal suspension of WT mice (WFMT). The distribution of myenteric neurons and the interstitial cells of Cajal (ICC), as well as the enteric nervous system (ENS) function, remained lower in the TgFMT group. These results suggest that the neuropathological constipation phenotypes of Tg2576 mice may be tightly linked to the dysbiosis of the fecal microbiota.

The effects of Saccharomyces boulardii on rat colonic hypermotility induced by repeated water avoidance stress and the potential mechanism

Background

Saccharomyces boulardii (Sb) has been reported to have the potential to regulate gut motility. The aim of this experiment was to explore the possible function of Sb in gut hypermotility elicited by repeated water avoidance stress (WAS).

Methods

Adult male Wistar rats (N = 24) were divided into one of the following three groups: control (C), NS (normal saline) + WAS group (N), and Sb + WAS group (S). A diarrhea-predominant irritable bowel syndrome (IBS-D) model in rats was induced using the WAS method. Gut motility was evaluated by stool pellet expulsion per hour. The contractile activity of the colonic muscle strips was measured using an RM6240 multichannel physiological signal instrument. qRT-PCR and immunohistochemistry were used to assess Toll-like receptor 4 (TLR4) expression in colon tissue. ELISA was used to measure the level of cytokines in the serum and colonic tissue. Also, the microbiota composition was determined using high-throughput 16S rRNA sequencing.

Result

The results showed that oral Sb decreased the WAS-induced increased defecation and colonic hypermotility in vivo. Furthermore, Sb also decreased the contractile amplitude of colonic circular muscle (CM) and longitudinal muscle (LM) strips in a dose-dependent manner in vitro. Repeated WAS increased TLR4 expression, but Sb reversed it. Sb also reduced interleukin-6 (IL-6), IL-1β, and interferon-γ (IFN-γ) levels in serum and colonic tissue, while increasing IL-10 levels in colonic tissue. Meanwhile, the rats from the NS + WAS group had decreased microbiota diversity and had lower relative abundances of Patescibacteria, Epsilonbacteraeota, Cyanobacteria, and Turicibacter compared with controls. The rats in the Sb + WAS group showed a tendency to increase the relative abundance of Blautia when compared to control rats and had lower relative abundances of Acidobacteria and Anaerostipes compared with the NS + WAS group.

Conclusion

Our findings demonstrated that Sb improved colonic hypermotility in rats, reversed the high-expression of TLR4 in the colon caused by repeated WAS, modulated cytokines in the colon and serum, and altered the gut microbiota, indicating that Sb may be useful for IBS-D.

Bibliometric and visual analysis of research on the links between the gut microbiota and pain from 2002 to 2021

BACKGROUND AND AIMS

The gut microbiota is involved in the regulation of pain, which is proved by plenty of evidence. Although a substantial quantity of research on the link between the gut microbiota and pain has emerged, no study has focused on the bibliometric analysis of this topic. We aim to present a bibliometric review of publications over the past 20 years and predict research hot spots.

METHODS

Relevant publications between 2002 and 2021 were extracted from the Science Citation Index-Expanded (SCI-EXPANDED) of the Web of Science Core Collection (WoSCC) database on April 22, 2022. CiteSpace (version 5.8 R3c), VOSviewer, the Online Analysis Platform of Literature Metrology, and the R package bibliometrix were used to analyze and visualize.

RESULTS

A total of 233 articles have been published between 2002 and 2021. The number of publication outputs increased rapidly since 2016. The collaboration network revealed that the USA, Baylor College of Medicine, and Vassilia Theodorou were the most influential country, institute, and scholar, respectively. Alimentary pharmacology and therapeutics and Gut were the most co-cited journal and Neurogastroenterology and Motility was the most productive journal. Visceral sensitivity, fibromyalgia, gastrointestinal, chronic pain, stress, gut microbiome, LGG, brain-gut axis, SLAB51, and sequencing were the top 10 clusters in co-occurrence cluster analysis. Keyword burst detection indicated that the brain-gut axis and short-chain fatty acid were the current research hot spots.

CONCLUSION

Research on the links between the gut microbiota and pain has increased rapidly since 2016. The current research focused on the brain-gut axis and short-chain fatty acid. Accordingly, the SCFAs-mediated mechanism of pain regulation will be a research direction of great importance on the links between the gut microbiota and pain. This study provided instructive assistance to direct future research efforts on the links between the gut microbiota and pain.

The impact of using a multistrain probiotic supplement on gastrointestinal function in children and adolescents with severe recessive dystrophic epidermolysis bullosa

BACKGROUND

Children and adolescents with severe recessive dystrophic epidermolysis bullosa (RDEB-S) often have severe constipation in addition to gastrointestinal dysbiosis, due to frequent antibiotic use and reduced oral diet. Constipation is treated with long-term use of high daily doses of macrogol gel (Movicol Paediatric PlainTM or LaxidoTM). Constipation is refractory to increases in fibre and fluids, and impacts severely on quality of life.

AIM

To study the initial impact and efficacy of using a multistrain probiotic supplement daily for 12 weeks in patients with RDEB-S. The authors sought to determine the impact of such a supplement on  gastrointestinal symptoms, stool consistency and the use of macrogol gel to treat constipation, as well as understanding patient reaction, palability and ease of use.

METHODS

Patients were identified through the epidermolysis bullosa tertiary multidisciplinary team clinic in July 2021. Patients were included if they had a diagnosis of RDEB-S, prescribed at least one sachet of macrogol gel and provided written consent to take part. Patients were provided, proprietary liquid multistrain probiotic supplement (Symprove™) with a high bacterial count, at a dose of 1 mL kg-1 once a day. Each patient completed an anonymous, nine-question, electronic survey to document symptoms and report overall findings at the start and end of a 12-week trial period.

RESULTS

Four patients with RDEB-S (two boys and two girls; age range 7-14 years) who met the inclusion criteria were approached to take part. All patients had chronic constipation requiring daily macrogol gel use (range 2-5 sachets per day). Three out of four (75%) completed the 12-week course. At baseline (before supplementation commenced), all three (100%) patients reported poor oral appetite, constipation, flatulence, abdominal bloating and pain, and frequent skin infections requiring oral antibiotics, with two of the three (66%) patients also having nausea. After 12 weeks of supplementation, all three patients (100%) reported a significant improvement in abdominal pain and bloating, nausea, stool consistency, stool frequency, flatulence and increased appetite. Two of the three patients (66%) were able to reduce their macrogol gel usage and the third patient (33%) was able to stop macrogol gel usage altogether during the study period. All three patients said they would choose to continue using the supplement if it was available.

CONCLUSION

We have shown in this case series that giving a multistrain probiotic supplement in patients with RDEB-S has the potential to improve stool consistency and reduce or prevent the need for chronic macrogol gel use. Future larger-scale, placebo-controlled trials are needed to confirm these results.

Gut microbiota plays a role in irritable bowel syndrome by regulating 5-HT metabolism

Irritable bowel syndrome (IBS) is a common chronic functional gastrointestinal disorder. Brain-gut-microbiota axis dysfunction is an important pathogenic factor for IBS, in which neurotransmitters and gut microbes play key roles. The gastrointestinal tract contains large amounts of serotonin (5-hydroxytryptamine, 5-HT), a neurotransmitter that has been strongly linked to IBS-related symptoms. More than 90% of serotonin is synthesized in the gut by enterochromaffin cells (ECs), and certain intestinal flora can affect the occurrence and development of IBS by regulating 5-HT and its metabolism. In this review, we will discuss the role of gut microbiota in IBS by regulating 5-HT.

Early life events in functional abdominal pain disorders in children

OBJECTIVES

Functional abdominal pain disorders (FAPDs) are common gastrointestinal problems in children, and the pathophysiology is thought to be multifactorial. Adverse early life events (ELE) induce alterations in the central nervous system, perhaps predisposing individuals to develop FAPDs. We aimed to study the potential adverse ELE that are associated with FAPDs.

METHODS

We steered a school-based survey involving 1000 children from 4 randomly selected schools. FAPDs were assessed using the translated Rome III questionnaire, and ELE were identified using a pre-tested, parental questionnaire. FAPDs were diagnosed using the Rome III criteria.

RESULTS

Hundred and eighty-two (182) children had FAPDs (62.1% girls, mean age 8.5, SD 2.1). ELE of them were compared with 571 children without FAPDs (51.1% girls, mean age 8.8, SD 1.9). According to the binary logistic regression analysis, family members with abdominal pain, family member with chronic pain other than abdominal pain, prenatal maternal complications and interventional deliveries, were recognized as potential risk factors for the development of FAPDs. Breast feeding over two years has shown to reduce the prevalence of FAPDs.a.

CONCLUSIONS

Prenatal maternal medical problems are associated a with higher prevalence of FAPDs later in life. Prolonged breastfeeding and normal vaginal delivery could be considered as factors that reduce the vulnerability of developing FAPDs in children. Therefore, minimizing pregnancy-related complications, encouraging vaginal deliveries, and encouraging breastfeeding are potentially valuable measures to prevent FAPDs during childhood.

A Comparison Between Rome III and Rome IV Criteria in Children with Chronic Abdominal Pain: A Prospective Observational Cohort Study

BACKGROUND

The Rome IV includes a redefinition of functional gastrointestinal disorders and diagnostic criteria. The present study aimed to compare the Rome III and Rome IV classification results and to reveal their differences in children with chronic abdominal pain.

METHODS

The present study is a prospective observational cohort study. Three hundred forty-four children, who were admitted to the pediatric gastroenterology clinic, had abdominal pain for more than 2 months, and were not diagnosed with an organic disease, were included in our study.

RESULTS

In children with chronic abdominal pain, Rome IV criteria did not cause a change in the number of patients diagnosed with functional abdominal pain disorders according to Rome III (89.8% vs 89.2%, P >.05). Functional abdominal pain and functional abdominal pain syndrome were the most common diagnoses in Rome III and functional abdominal pain, not otherwise specified in Rome IV. When compared to Rome III, while the diagnosis of functional dyspepsia increased in Rome IV, irritable bowel syndrome decreased.

CONCLUSION

In children with chronic abdominal pain, Rome IV criteria did not cause a change in the number of patients diagnosed with functional abdominal pain disorders according to Rome III, but it caused a diagnostic shift. It was seen that some of the children diagnosed with irritable bowel syndrome in Rome III shifted to functional dyspepsia diagnosis in Rome IV.

Gastrointestinal symptoms in COVID-19: the long and the short of it

PURPOSE OF REVIEW

A large and growing number of patients have persistent gastrointestinal symptoms that they attribute to COVID-19. SARS-CoV-2, the virus that causes COVID-19, replicates within the gut and acute COVID-19 is associated with alteration of the gut microbiome. This article reviews recent observational data related to gastrointestinal symptoms in 'long COVID' and discusses pathophysiologic mechanisms that might explain persistent post-COVID gastrointestinal symptoms.

RECENT FINDINGS

Gastrointestinal symptoms are present in half of the patients with acute COVID-19, persist 6 months after COVID-19 in 10-25% of patients, and are rated as the most bothersome symptom in 11% of all patients. These symptoms include heartburn, constipation, diarrhoea and abdominal pain and decline in prevalence with the passage of time. Long COVID gastrointestinal symptoms are associated with mental health symptoms (anxiety and depression) that predate COVID-19 and also with mental health symptoms that are concurrent, after recovery from COVID-19. The cause of long COVID gastrointestinal symptoms is unknown and hypotheses include the SARS-CoV-2 virus itself, which infects the gastrointestinal tract; COVID-19, which can be accompanied by gut microbiome changes, a profound systemic inflammatory response and critical illness; and/or effects of pandemic stress on gastrointestinal function and symptom perception, which may be unrelated to either SARS-CoV-2 or to COVID-19.

SUMMARY

New, persistent gastrointestinal symptoms are commonly reported after recovery from COVID-19. The pathophysiology of these symptoms is unknown but likely to be multifactorial.

Compositional Changes in the Gut Microbiota of Responders and Non-responders to Probiotic Treatment Among Patients With Diarrhea-predominant Irritable Bowel Syndrome: A Post Hoc Analysis of a Randomized Clinical Trial

Background/Aims

We aim to evaluate the differences in the microbiome of responders and non-responders, as well as predict the response to probiotic therapy, based on fecal microbiome data in patients with diarrhea-predominant irritable bowel syndrome (IBS-D).

Methods

A multi-strain probiotics that contains Lactobacillus acidophilus (KCTC 11906BP), Lactobacillus plantarum (KCTC11867BP), Lactobacillus rhamnosus (KCTC 11868BP), Bifidobacterium breve (KCTC 11858BP), Bifidobacterium lactis (KCTC 11903BP), Bifidobacterium longum (KCTC 11860BP), and Streptococcus thermophilus (KCTC 11870BP) were used. Patients were categorized into probiotic and placebo groups, and fecal samples were collected from all patients before and at the end of 8 weeks of treatment. The probiotic group was further divided into responders and non-responders. Responders were defined as patients who experienced adequate relief of overall irritable bowel syndrome symptoms after probiotic therapy. Fecal microbiota were investigated using Illumina MiSeq and analyzed using the EzBioCloud 16S database and microbiome pipeline (https://www.EZbiocloud.net).

Results

There was no significant difference in the alpha and beta diversity between the responder and non-responder groups. The abundances of the phylum Proteobacteria and genus Bacteroides significantly decreased after probiotic treatment. Bifidobacterium bifidum, Pediococcus acidilactici, and Enterococcus faecium showed a significantly higher abundance in the probiotic group after treatment compared to the placebo group. Enterococcus faecalis and Lactococcus lactis were identified as biomarkers of non-response to probiotics. The abundance of Fusicatenibacter saccharivorans significantly increased in the responders after treatment.

Conclusions

Probiotic treatment changes some composition of fecal bacteria in patients with IBS-D. E. faecalis and L. lactis may be prediction biomarkers for non-response to probiotics. Increased abundance of F. sccharivorans is correlated to symptom improvement by probiotics in patients with IBS-D.

Alterations in gut microbiota are related to metabolite profiles in spinal cord injury

Studies have shown that gut microbiota metabolites can enter the central nervous system via the blood-spinal cord barrier and cause neuroinflammation, thus constituting secondary injury after spinal cord injury. To investigate the correlation between gut microbiota and metabolites and the possible mechanism underlying the effects of gut microbiota on secondary injury after spinal cord injury, in this study, we established mouse models of T8-T10 traumatic spinal cord injury. We used 16S rRNA gene amplicon sequencing and metabolomics to reveal the changes in gut microbiota and metabolites in fecal samples from the mouse model. Results showed a severe gut microbiota disturbance after spinal cord injury, which included marked increases in pro-inflammatory bacteria, such as Shigella, Bacteroides, Rikenella, Staphylococcus, and Mucispirillum and decreases in anti-inflammatory bacteria, such as Lactobacillus, Allobaculum, and Sutterella. Meanwhile, we identified 27 metabolites that decreased and 320 metabolites that increased in the injured spinal cord. Combined with pathway enrichment analysis, five markedly differential amino acids (L-leucine, L-methionine, L-phenylalanine, L-isoleucine and L-valine) were screened out, which play a pivotal role in activating oxidative stress and inflammatory responses following spinal cord injury. Integrated correlation analysis indicated that the alteration of gut microbiota was related to the differences in amino acids, which suggests that disturbances in gut microbiota might participate in the secondary injury through the accumulation of partial metabolites that activate oxidative stress and inflammatory responses. Findings from this study provide a new theoretical basis for improving the secondary injury after spinal cord injury through fecal microbial transplantation.

Population-based metagenomics analysis reveals altered gut microbiome in sarcopenia: data from the Xiangya Sarcopenia Study

BACKGROUND

Several studies have examined gut microbiota and sarcopenia using 16S ribosomal RNA amplicon sequencing; however, this technique may not be able to identify altered specific species and functional capacities of the microbes. We performed shotgun metagenomic sequencing to compare the gut microbiome composition and function between individuals with and without sarcopenia.

METHODS

Participants were from a community-based observational study conducted among the residents of rural areas in China. Appendicular skeletal muscle mass was assessed using direct segmental multi-frequency bioelectrical impedance and grip strength using a Jamar Hydraulic Hand dynamometer. Physical performance was evaluated using the Short Physical Performance Battery, 5-time chair stand test and gait speed with the 6 m walk test. Sarcopenia and its severity were diagnosed according to the Asian Working Group for Sarcopenia 2019 algorithm. The gut microbiome was profiled by shotgun metagenomic sequencing to determine the microbial composition and function. A gut microbiota-based model for classification of sarcopenia was constructed using the random forest model, and its performance was assessed using the area under receiver-operating characteristic curve (AUC).

RESULTS

The study sample included 1417 participants (women: 58.9%; mean age: 63.3 years; sarcopenia prevalence: 10.0%). β-diversity indicated by Bray-Curtis distance (genetic level: P = 0.004; taxonomic level of species: P = 0.020), but not α-diversity indicated by Shannon index (genetic level: P = 0.962; taxonomic level of species: P = 0.922), was significantly associated with prevalent sarcopenia. After adjusting for potential confounders, participants with sarcopenia had higher relative abundance of Desulfovibrio piger (P = 0.003, Q = 0.090), Clostridium symbiosum (P < 0.001, Q = 0.035), Hungatella effluvii (P = 0.003, Q = 0.090), Bacteroides fluxus (P = 0.002, Q = 0.089), Absiella innocuum (P = 0.002, Q = 0.072), Coprobacter secundus (P = 0.002, Q = 0.085) and Clostridium citroniae (P = 0.001, Q = 0.060) than those without sarcopenia. The relative abundance of six species (Desulfovibrio piger, Clostridium symbiosum, Hungatella effluvii, Bacteroides fluxus, Absiella innocuum, and Clostridium citroniae) was also positively associated with sarcopenia severity. A differential species-based model was constructed to separate participants with sarcopenia from controls. The value of the AUC was 0.852, suggesting that model has a decent discriminative performance. Desulfovibrio piger ranked the highest in this model. Functional annotation analysis revealed that the phenylalanine, tyrosine, and tryptophan biosynthesis were depleted (P = 0.006, Q = 0.071), while alpha-Linolenic acid metabolism (P = 0.008, Q = 0.094), furfural degradation (P = 0.001, Q = 0.029) and staurosporine biosynthesis (P = 0.006, Q = 0.072) were enriched in participants with sarcopenia. Desulfovibrio piger was significantly associated with staurosporine biosynthesis (P < 0.001).

CONCLUSIONS

This large population-based observational study provided empirical evidence that alterations in the gut microbiome composition and function were observed among individuals with sarcopenia.

Microbiota- Brain-Gut-Axis Relevance to Parkinson's Disease: Potential Therapeutic Effects of Probiotics

Parkinson's disease (PD) is the second most common type of neurogenerative disease among middleaged and older people, characterized by aggregation of alpha-synuclein and dopaminergic neuron loss. The microbiota- gut-brain axis is a dynamic bidirectional communication network and is involved in the pathogenesis of PD. The aggregation of misfolded protein alpha-synuclein is a neuropathological characteristic of PD, originates in the gut and migrates to the central nervous system (CNS) through the vagus nerve and olfactory bulb. The change in the architecture of gut microbiota increases the level short-chain fatty acids (SCFAs) and other metabolites, acting on the neuroendocrine system and modulating the concentrations of gamma-Aminobutyric acid (GABA), serotonin, and other neurotransmitters. It also alters the vagus and intestinal signalling, influencing the brain and behaviour by activating microglia and systemic cytokines. Both experimental and clinical reports indicate the role of intestinal dysbiosis and microbiota host interaction in neurodegeneration. Probiotics are live microorganisms that modify the gut microbiota in the small intestine to avoid neurological diseases. Probiotics have been shown in clinical and preclinical studies to be effective in the treatment of PD by balancing the gut microbiota. In this article, we described the role of gut-microbiota in the pathogenesis of PD. The article aims to explore the mechanistic strategy of the gut-brain axis and its relation with motor impairment and the use of probiotics to maintain gut microbial flora and prevent PD-like symptoms.

Randomized, Double-Blind Placebo-Controlled Trial to Assess the Effect of Probiotics on Irritable Bowel Syndrome in Veterans With Gulf War Illness

Background

Many veterans who served in Operation Desert Storm (August 1990 to March 1991) experienced a complex of symptoms of unknown etiology called Gulf War illness (GWI), which significantly impacts the health and quality of life (QOL) and may have contributed to irritable bowel syndrome (IBS).

Methods

We performed a prospective, double-blind placebocontrolled study to determine the efficacy of the multistrain De Simone Formulation probiotic containing 8 strains of bacteria on symptoms of IBS and GWI. Veterans of Operation Desert Storm who had IBS and ≥ 2 nonintestinal symptoms of GWI were included. The primary study endpoint was change in bowel symptom score. The secondary endpoints were mean change in symptoms, QOL, and extra-intestinal and posttraumatic stress disorder (PTSD) symptoms.

Results

A total of 101 Gulf War veterans with IBS and GWI were screened at the Veteran Affairs Medical Center in Salt Lake City, Utah. The study was completed by 53 veterans; 47 (89%) were male with a mean (SD) age of 55 (8) years. The probiotic did not improve IBS symptoms or other extra-intestinal symptoms common to IBS and GWI.

Conclusions

Our study did not demonstrate statistically significant improvement in IBS symptoms or QOL after treatment with the probiotic. We also did not find any improvement in symptoms of GWI or PTSD.

Potential tolerability of ancient grains in non-celiac wheat sensitivity patients: A preliminary evaluation

BACKGROUND AND AIMS

A wheat-free diet (WFD) represents the elective treatment for Non-celiac Wheat Sensitivity (NCWS) patients. Preliminary reports have shown a possible better tolerability of ancient grains in these subjects. The aim of this observational study was to evaluate the frequency of consumption of ancient grains and its correlation with clinical manifestations in NCWS patients.

METHODS

223 NCWS patients were recruited, and their consumption of ancient grains was monitored. Participants were first administered a modified version of the Pavia/Biagi questionnaire to investigate their adherence to "modern WFD." The appearance/exacerbation of symptoms after ingestion of ancient grains was then assessed with WHO toxicity grading scale.

RESULTS

50.2% of the recruited patients reported consuming ancient grains before NCWS diagnosis; the diagnostic delay in this group was significantly higher than in non-consumers [median (range) 72 (6-612) vs. 60 months (3-684), P = 0.03] and these patients reported lower frequency of constipation (P = 0.04). Of the 107 patients with optimal adherence to modern WFD, 14 reported eating ancient wheat after NCWS diagnosis. Among them, 5 reported milder symptoms than those caused by modern wheat intake and 3 had an excellent tolerability without symptoms. Timilia/Tumminia variety was the most frequently used ancient grain.

CONCLUSIONS

NCWS patients who consume ancient grains may receive a late diagnosis due to the possible clinical benefit (tolerability) obtained with these grains. Even after diagnosis, 10% of the patients still consumed ancient grains and had mild or no symptoms. Further studies are required to define the pathophysiological mechanism behind their putative greater tolerability.

Clinical study on sequential treatment of severe diarrhea irritable bowel syndrome with precision probiotic strains transplantation capsules, fecal microbiota transplantation capsules and live combined bacillus subtilis and enterococcus faecium capsules

Objective

To study the effect of precision probiotic strains transplantation capsules on diarrhea irritable bowel syndrome compared with fecal microbiota transplantation capsules and live combined bacillus subtilis and enterococcus faecium capsules.

Methods

Two patients with severe irritable bowel syndrome were treated with precision probiotic strains transplantation capsules, fecal microbiota transplantation capsules and live combined bacillus subtilis and enterococcus faecium capsules in sequence. IBS-SSS, IBS-QoL, GSRS, stool frequency, stool character, degree of abdominal pain, GAD-7, and PHQ9 scores of patients at 0, 2, 4, 6, 8, 10, and 12 weeks of treatment were monitored and recorded, and stool samples were collected for metagenomics and metabolomics.

Results

It was found that the IBS-SSS score of patient case 1 decreased by 175 points and that of patient case 2 decreased by 100 points after treatment of precision probiotic strains transplantation capsules. There was no significant decrease after fecal microbiota transplantation capsules and live combined bacillus subtilis and enterococcus faecium capsules were used. At the same time, compared with fecal microbiota transplantation and live combined bacillus subtilis and enterococcus faecium capsules, the IBS QoL, stool frequency, stool character, degree of abdominal pain and GAD-7 score of patient case 1 improved more significantly by the precision probiotic strains transplantation capsules. And the stool frequency and stool character score of patient case 2 decreased more significantly. Intestinal microbiota also improved more significantly after the precise capsule transplantation treatment. And we found Eubacterium_ Eligens showed the same change trend in the treatment of two patients, which may play a role in the treatment.

Conclusion

precision probiotic strains transplantation capsules is more beneficial to improve the intestinal microbiota of patients than microbiota transplantation capsule and live combined bacillus subtilis and enterococcus faecium capsules, so as to better alleviate clinical symptoms. This study provides a more perfect and convenient therapeutic drugs for the treatment of IBS.

Bacteroides fragilis ameliorates Cronobacter malonaticus lipopolysaccharide-induced pathological injury through modulation of the intestinal microbiota

Cronobacter has attracted considerable attention due to its association with meningitis and necrotizing enterocolitis (NEC) in newborns. Generally, lipopolysaccharide (LPS) facilitates bacterial translocation along with inflammatory responses as an endotoxin; however, the pathogenicity of Cronobacter LPS and the strategies to alleviate the toxicity were largely unknown. In this study, inflammatory responses were stimulated by intraperitoneal injection of Cronobacter malonaticus LPS into Sprague–Dawley young rats. Simultaneously, Bacteroides fragilis NCTC9343 were continuously fed through gavage for 5 days before or after injection of C. malonaticus LPS to evaluate the intervention effect of B. fragilis. We first checked the morphological changes of the ileum and colon and the intestinal microbiota and then detected the generation of inflammatory factors, including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10) and the expression of Toll-like receptor 4 (TLR4), occludin, claudin-4, and iNOs. The results indicated that C. malonaticus LPS exacerbated intestinal infection by altering gut microbe profile, tight junction protein expression, and releasing inflammatory factors in a time- and dose-dependent manner. Intriguingly, treatment with B. fragilis obviously diminished the pathological injuries and expression of TLR4 caused by C. malonaticus LPS while increasing gut microbes like Prevotella-9. We note that Shigella, Peptoclostridium, and Sutterella might be positively related to C. malonaticus LPS infection, but Prevotella-9 was negatively correlated. The results suggested that the intestinal microbiota is an important target for the prevention and treatment of pathogenic injuries induced by C. malonaticus LPS.

Fecal Microbiota Transplantation Combined with a Low FODMAP Diet for the Treatment of Irritable Bowel Syndrome with Predominant Diarrhea

BACKGROUND

Fecal microbiota transplantation (FMT) has been found to be effective in irritable bowel syndrome with predominant diarrhea (IBS-D). We conducted this study to determine the impact of a low FODMAP diet (LFD) on the gut microbiota and the efficacy of FMT in the treatment of IBS-D.

METHODS

A retrospective analysis of a single-arm open-label prospective study was conducted to investigate the impact of FMT alone (n = 40) and FMT+LFD (n = 40) in refractory IBS-D. The IBS-quality of life (QOL), IBS-severity scoring system (SSS), gastrointestinal symptom rating scale (GSRS), Hamilton anxiety scale (HAMA), and Hamilton depression scale (HAMD) were used to evaluate the efficacy, and partial 16S rDNA amplicon sequencing was used to profile the microbiota.

RESULTS

The response rates were higher in the FMT+LFD group than in the FMT group (1 mo, 3 mo, 6 mo: 70.0% vs. 55.0%, 67.5% vs. 57.5%, 62.5% vs. 27.5%, respectively). The FMT+LFD group showed significantly better improvement in IBS-QOL at 1, 3, and 6 months; IBS-SSS at 6 months; and GSRS at 1 month compared to FMT alone. Changes in HAMA and HAMD were similar in the two groups. The LFD significantly upregulated the FMT-induced microbial diversity (OTUs: 666 vs. 574, Adonis: P = 0.02) and significantly strengthened the upregulation of Bacteroides, Alistipes, and Ruminococcaceae_UCG-002 and the downregulation of Bifidobacterium.

CONCLUSION

An LFD enhanced the efficacy of FMT, increased the gut microbial diversity after FMT, and strengthened the inhibitory effect of FMT on conditional pathogens.

Explore and Analyze the Composition and Characteristics of Intestinal Microbiota between Gastric Cancer Patients and Healthy People

Gastric cancer is one of the most common malignant tumors in the world. As the intestine is downstream of the digestive tract, the occurrence of gastric cancer may have a certain significant impact on it. Therefore, it is particularly important to find out the intestinal bacteria closely related to gastric cancer, to identify the specific flora related to gastric cancer, and to maintain the stability of the core structure of intestinal microecology in patients with gastric cancer. Based on this, the fecal samples of gastric cancer patients and healthy people were collected, and the diversity and composition of intestinal flora in patients with gastric cancer were analyzed by 16S rRNA sequencing technology. We found that there was no significant difference in the diversity and abundance of intestinal flora between gastric cancer patients and healthy people. The relative abundance of Faecalibacterium, Bifidobacterium, and Subdoligranulum in the intestinal tract of patients with gastric cancer was significantly lower than that in healthy people, while the relative abundance of Enterococcus, Streptococcus, and Bacteroides was increased. This study found that there were six kinds of intestinal microflora closely related to the occurrence of gastric cancer, which provided a theoretical basis for further exploring the pathogenesis of gastric cancer.

Relation of gut microbiota and postoperative gastrointestinal dysfunction in older patients with colon cancer undergoing elective colon resection: a protocol for a prospective, observational cohort study

INTRODUCTION

Gut microbiota (GM) appears critical for gastrointestinal symptoms, but whether alterations in GM are associated with increased risk of postoperative gastrointestinal dysfunction (POGID) in older patients with colon cancer (CC) undergoing elective colon resection remains unclear.

METHODS AND ANALYSIS

This study aims to prospectively recruit 284 elderly patients with CC undergoing elective colon resection. GM of fresh faeces specimens is characterised using 16S rRNA gene sequencing. Data are collected preoperatively, daily postoperatively during the in-hospital stay, and follow-up visits are scheduled four times within 30 days after discharge. Associations with POGID will be investigated using logistic regression models to calculate ORs with 95% CIs. The models include the adjustment for age, sex, frequency of spicy diet, coffee drinking and tea drinking, tobacco and alcohol history, diabetes, obesity, gastroenteritis, preoperative gut microbial composition. Furthermore, we will use joint modelling for longitudinal data to study several outcome variables simultaneously.

ETHICS AND DISSEMINATION

This study was approved by the Institutional Review Board of West China Hospital, Sichuan University (IRB Number: 20201334). The results will be disseminated through peer-reviewed publications or conference presentations.

TRIAL REGISTRATION NUMBER

It has been registered in PROSPERO, number CRD42019145032. It has been registered in the Chinese clinical trial registry, number ChiCTR2100043646.

Current perspectives on irritable bowel syndrome: a narrative review

The pathophysiology of irritable bowel syndrome (IBS) has not yet been fully elucidated. We reviewed articles addressing IBS that have been published in the last 2 years and selected papers related to IBS pathophysiology and treatment. Studies of intestinal bacteria, low-grade mucosal inflammation, and increased mucosal permeability—factors involved in the pathophysiology of IBS—have been conducted. In addition, the involvement of intestinal bacteria in IBS pathology has been clarified; many studies of treatments related to intestinal bacteria have been reported. Moreover, several studies address the effect on IBS of antidepressants and psychotherapy through the brain–gut axis. The contents of these papers are described in this narrative review.