United European Gastroenterology (UEG) and European Society for Neurogastroenterology and Motility (ESNM) consensus on functional dyspepsia

Clinical Practice Updates: AGA Clinical Practice Update on GI Manifestations and Autonomic or Immune Dysfunction in Hypermobile Ehlers-Danlos Syndrome: Expert Review

DESCRIPTION

The purpose of this Clinical Practice Update Expert Review is to describe key principles in the evaluation and management of patients with disorders of gut-brain interaction (DGBI) and hypermobile Ehlers-Danlos syndrome (hEDS) or hypermobility spectrum disorders (HSDs) with coexisting postural orthostatic tachycardia syndrome (POTS) and/or mast cell activation syndrome (MCAS).

METHODS

This expert review/commentary was commissioned and approved by the American Gastroenterological Association (AGA) Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the Clinical Practice Updates Committee and external peer review through standard procedures of Clinical Gastroenterology and Hepatology. These Best Practice Advice statements were drawn from a review of the published literature and from expert opinion. Because systematic reviews were not performed, these Best Practice Advice statements do not carry formal ratings regarding the quality of evidence or strength of the presented considerations. BEST PRACTICE ADVICE 1: Clinicians should be aware of the observed associations between hEDS or HSDs and POTS and/or MCAS and their overlapping gastrointestinal (GI) manifestations; while theoretical explanations exist, experimental evidence of the biological mechanisms that explain relationships is limited and evolving. BEST PRACTICE ADVICE 2: Testing for POTS/MCAS should be targeted to patients presenting with clinical manifestations of POTS/MCAS, but universal testing for POTS/MCAS in all patients with hEDS/HSDs is not supported by the current evidence. BEST PRACTICE ADVICE 3: Gastroenterologists seeing patients with DGBI should inquire about joint hypermobility and strongly consider incorporating the Beighton score for assessing joint hypermobility into their practice as a screening tool; if the screen is positive, gastroenterologists may consider applying 2017 diagnostic criteria to diagnose hEDS (https://www.ehlers-danlos.com/wp-content/uploads/2017/05/hEDS-Dx-Criteria-checklist-1.pdf) or offer appropriate referral to a specialist where resources are available. BEST PRACTICE ADVICE 4: Testing for POTS through postural vital signs (eg, symptomatic increase in heart rate of 30 beats/min or more with 10 minutes of standing during an active stand or head-up tilt table test in the absence of orthostasis) and referral to specialty practices (eg, cardiology or neurology) for autonomic testing should be considered in patients with hEDS/HSDs and refractory GI symptoms who also report orthostatic intolerance after exclusion of medication side effects and appropriate lifestyle or behavioral modifications (eg, adequate hydration and physical exercise) have been attempted but is not required for all patients with hEDS/HSDs who report GI symptoms alone. BEST PRACTICE ADVICE 5: In patients presenting to gastroenterology providers, testing for mast cell disorders including MCAS should be considered in patients with hEDS/HSDs and DGBI who also present with episodic symptoms that suggest a more generalized mast cell disorder (eg, visceral and somatic pain, pruritus, flushing, sweating, urticaria, angioedema, wheezing, tachycardia, abdominal cramping, vomiting, nausea, diarrhea, urogynecological and neurological complaints) involving 2 or more physiological systems (eg, cutaneous, GI, cardiac, respiratory, and neuropsychiatric), but current data do not support the use of these tests for routine evaluation of GI symptoms in all patients with hEDS/HSDs without clinical or laboratory evidence of a primary or secondary mast cell disorder. BEST PRACTICE ADVICE 6: If MCAS is suspected, diagnostic testing with serum tryptase levels collected at baseline and 1-4 hours following symptom flares may be considered by the gastroenterologist; increases of 20% above baseline plus 2 ng/mL are necessary to demonstrate evidence of mast cell activation. BEST PRACTICE ADVICE 7: If a diagnosis of MCAS is supported through clinical and/or laboratory features, patients should be referred to an allergy specialist or mast cell disease research center where additional testing (eg, urinary N-methylhistamine, leukotriene E4, 11β-prostaglandin F2) may be performed. BEST PRACTICE ADVICE 8: Diagnostic evaluation of GI symptoms consistent with DGBI in patients with hEDS/HSDs and comorbid POTS and/or MCAS should follow a similar approach to the evaluation of DGBI as in the general population including the use of a positive symptom-based diagnostic strategy and limited noninvasive testing. BEST PRACTICE ADVICE 9: Testing for celiac disease may be considered earlier in the diagnostic evaluation of patients with hEDS/HSDs who report a variety of GI symptoms and not only limited to those with diarrhea. There is insufficient research to support routine testing for disaccharidase deficiencies or other diet-mediated mechanisms as causes of GI symptoms in hEDS/HSDs. BEST PRACTICE ADVICE 10: Diagnostic testing for functional defecation disorders with anorectal manometry, balloon expulsion test, or defecography should be considered in patients with hEDS/HSDs and lower GI symptoms such as incomplete evacuation given the high prevalence of pelvic floor dysfunction, especially rectal hyposensitivity, in this population. BEST PRACTICE ADVICE 11: In patients with hEDS/HSDs and comorbid POTS who report chronic upper GI symptoms, timely diagnostic testing of gastric motor functions (eg, measurement of gastric emptying and/or accommodation) should be considered after appropriate exclusion of anatomical and structural diseases, as abnormal gastric emptying may be more common than in the general population. BEST PRACTICE ADVICE 12: Medical management of GI symptoms in hEDS/HSDs and POTS/MCAS should focus on treating the most prominent GI symptoms and abnormal GI function test results. In addition to general DGBIs and GI motility disorder treatment, management should also include treating any symptoms attributable to POTS and/or MCAS. BEST PRACTICE ADVICE 13: Treatment of POTS may include increasing fluid and salt intake, exercise training, and use of compression garments. Special pharmacological treatments for volume expansion, heart rate control, and vasoconstriction with integrated care from multiple specialties (eg, cardiology, neurology) should be considered in patients who do not respond to conservative lifestyle measures. BEST PRACTICE ADVICE 14: When MCAS is suspected, patients can benefit from treatment with histamine receptor antagonists and/or mast cell stabilizers, in addition to avoiding triggers such as certain foods, alcohol, strong smells, temperature changes, mechanical stimuli (eg, friction), emotional distress (eg, pollen, mold), or specific medications (eg, opioids, nonsteroidal anti-inflammatory agents, iodinated contrast). BEST PRACTICE ADVICE 15: Besides general nutritional support, special diets including a gastroparesis diet (ie, small particle diet) and various elimination diets (eg, low fermentable carbohydrates, gluten- or dairy-free, low-histamine diets) can be considered for improving GI symptoms. Dietary interventions should be delivered with appropriate nutritional counseling or guidance to avoid the pitfalls of restrictive eating. BEST PRACTICE ADVICE 16: Management of chronic GI symptoms in patients with hEDS/HSDs who do not exhibit symptoms consistent with POTS or MCAS should align with existing approaches to management of DGBI and GI motility disorders in the general population, including integrated multidisciplinary care involving multiple specialties, where appropriate (eg, cardiology, rheumatology, dietician, psychology).

Gastric Accommodation Testing Using Hybrid Nuclear Imaging Volumetry and Combined High-Resolution Manometry-Nutrient Drink Test: A Pilot Study in Healthy Individuals

BACKGROUND

Gastric accommodation (GA) testing is gaining clinical recognition as novel and minimally invasive modalities emerge. We investigated the feasibility of hybrid nuclear imaging volumetry (SPECT/CT) and combined high-resolution manometry-nutrient drink test (HRM-NDT) to assess GA.

METHODS

In this non-randomized pilot study, [99mTc]NaTcO4 gastric SPECT/CT (250 mL protocol) and proximal gastric HRM-NDT (~60 mL/min protocol) were performed separately within 30 days using Ensure Gold test meal (1.05 kcal/mL; Abbott). GA parameters were measured, and their preliminary associations were examined using Spearman's ρ and Hoeffding's D correlation tests. Data were presented as median ± normalized median absolute deviation.

KEY RESULTS

Twenty healthy, asymptomatic individuals (11 females; 23.5 ± 2.2 years, 23.7 ± 2.2 kg/m2) completed both procedures without serious adverse events and interrupted sessions. The accommodation volume and postprandial-to-fasting volume ratio from SPECT/CT were 325.8 ± 28.5 mL and 5.31 ± 1.28, respectively. During HRM-NDT, the nadir-intragastric pressure (IGP) was -6.6 ± 3.6 mmHg at an ingested volume of 360.0 ± 177.9 mL, and the area-under-curve of IGP was -1566.0 ± 1596.8 mmHg·mL. The maximum tolerated volume for reaching satiety/maximum discomfort was 450.0 ± 177.9 mL, and the area-under-curve of satiation score was 900.0 ± 266.9 satiation-unit·mL. The area-under-curve of IGP showed significant associations with maximum tolerated volume (ρ: -0.702; D: 0.234) and the area-under-curve of satiation score (D: 0.119): all p < 0.01. No correlations were found between volumetric with manometric and subjective NDT GA parameters.

CONCLUSIONS & INFERENCES

SPECT/CT and HRM-NDT are feasible and tolerable techniques for measuring GA in healthy individuals. Thus, determining their diagnostic utility among patient populations requires further optimization and standardization.

[Guideline on functional dyspepsia, a disorder of gut-brain-interaction (DGBI): S1 Guideline of the German Society for Neurogastroenterology and Motility (DGNM)]

Functional dyspepsia is common and classified as a disorder of gut-brain interaction (DGBI). The prevalence is estimated around 10 % of the population. Diagnosis is based on symptoms, which are based on the Rome IV criteria, in combination with diagnostic procedures that may include laboratory testing, Helicobacter pylori testing, upper gastrointestinal endoscopy, abdominal ultrasound, and other examinations, depending on the severity, duration and presence of alarming symptoms. Therapeutic procedures include psychoeducation, dietary counseling, mind-body procedures, psychotherapy and medication. The S1 guideline summarizes the current state of knowledge and allows a targeted approach based on the currently available medical evidence.

Review Article: Rome Foundation Working Team Report: Consensus Statement on the Design and Conduct of Behavioural Clinical Trials for Disorders of Gut-Brain Interaction

BACKGROUND

Brain-gut behaviour therapies (BGBT) have gained widespread acceptance as therapeutic modalities for the management of disorders of gut-brain interaction (DGBI). However, existing treatment evaluation methods in the medical field fail to capture the specific elements of scientific rigour unique to behavioural trial evaluation.

AIMS

To offer the first consensus on the development and testing of BGBT in DGBI.

METHODS

An international, interdisciplinary team of experts developed a consensus statement heavily informed by best practice recommendations for behavioural clinical trials for chronic diseases, organised by a selected treatment development model.

RESULTS

We suggest an existing behavioural treatment development model that has an iterative progression aligned with the drug development model with nuances specific to BGBT. We describe the iterative phases through initial discovery and experimental work, assembly of a mechanistic pathway and candidate treatment components, treatment refinement and optimisation, initial proof-of-concept, feasibility of clinical trials and, finally, confirmatory efficacy and effectiveness testing. We delineate recommendations for and provide examples that lend themselves to gastroenterologists planning to develop or test BGBT, reviewing proposals for or results from BGBT studies or writing management guidelines for DGBI.

CONCLUSIONS

This working team report facilitates a shared understanding of the elements of scientific rigour necessary for BGBT development and could support future standards on which BGBT are evaluated in gastroenterology.

Ultrasonographic assessment of gastric and gallbladder dynamics in human health and disease

The diagnosis of functional disorders of the upper gastrointestinal tract relies on clinical evaluation after exclusion of most frequent organic diseases. Diagnostic techniques contribute to better characterization of disease, choice of specific therapy, and follow-up. Functional ultrasonography was introduced in the early '80 s for the non-invasive study of gastric and gallbladder emptying without ionizing radiation, during fasting and postprandially. This technique detects dysfunctional motility in several gastrointestinal and systemic conditions, and can be used along with the assessment of real-time satiety and gastrointestinal symptoms after food ingestion, and dosing of hormones involved in the modulation of gastrointestinal and metabolic homeostasis. Functional ultrasonography has been increasingly used to explore the gastrointestinal pathophysiology, the gut-brain interaction, the effects of drugs (such as antidiabetics), the response to specific dietary and feeding patterns, and to support the development of nutraceuticals. In this evolving scenario, ultrasonography stands as a widely available, highly sustainable, non-invasive, repeatable, safe and low-cost tool, as compared with more expensive, less sustainable or still scarcely standardized procedures to study gastric and gallbladder motility as scintigraphy, wireless motility capsule tests, 13C breath tests, or magnetic resonance imaging. Functional ultrasonography not only provides reliable data in experimental protocols, but also in the assessment of clinical conditions as dyspeptic symptoms, diabetes, gastroenteric and neurological diseases, critical illness, and as a benchmark to evaluate the gastrointestinal effects of innovative drugs.

A Non-Pharmacological Paradigm Captures the Complexity in the Mechanism of Action of Poliprotect Against Gastroesophageal Reflux Disease and Dyspepsia

When the protective mechanisms of the gastroesophageal mucosa are overwhelmed by injurious factors, the structural and functional mucosal integrity is compromised, resulting in a wide spectrum of disorders. Poliprotect has recently been shown to be non-inferior to standard-dose omeprazole for the treatment of endoscopy-negative patients with heartburn and/or epigastric pain or burning. Here, we provide preclinical data describing the mechanism of action of the Poliprotect formulation, a 100% natural, biodegradable, and environmental friendly medical device according to EU 2017/745 and containing UVCB (unknown or variable composition, complex-reaction products, or biological materials) substances of botanical and mineral origin, according to the REACH and European Chemical Agency definitions. Different in vitro assays demonstrated the capability of Poliprotect to adhere to mucus-secreting gastric cells and concomitantly deliver a local barrier with buffering and antioxidant activity. In studies conducted in accordance with systems biology principles, we evaluated the effects of this barrier on human gastric cells exposed to acidic stress. Biological functions identified via Ingenuity Pathway Analysis highlighted the product's ability to create a microenvironment that supports the mucosal structural and functional integrity, promotes healing, and restores a balanced mucosal inflammatory status. Additionally, transepithelial electrical resistance and an Ussing chamber showed the product's capability of preserving the integrity of the gastric and esophageal epithelial barriers when exposed to an acid solution. Two in vivo models of erosive gastropathy further highlighted its topical protection against ethanol- and drug-induced mucosal injury. Overall, our findings sustain the feasibility of a paradigm shift in therapeutics R&D by depicting a very innovative and desirable mode of interaction with the human body based on the emerging biophysical, rather than the pharmacological properties of these therapeutic agents.

Rome Foundation and international neurogastroenterology and motility societies' consensus on idiopathic gastroparesis

To establish a consensus on the definition and management of idiopathic gastroparesis, international experts (selected by neurogastroenterology and motility societies and initiated by the Rome Foundation) devised 144 statements using the Delphi method, with at least 80% agreement required. This consensus defined idiopathic gastroparesis as the presence of symptoms associated with delayed gastric emptying in the absence of mechanical obstruction. Nausea and vomiting were identified as cardinal symptoms. Frequently co-existing symptoms are early satiation and postprandial fullness. Diagnosis requires the presence of these symptoms alongside delayed gastric emptying, measured by a 4 h scintigraphy or gastric emptying breath test of a mixed composition meal in the absence of mechanical obstruction. Therapeutic options with proven efficacy were sparse. Dietary adjustments, nutritional support (per guidelines from the European Society for Clinical Nutrition and Metabolism for substantial weight loss or intractable vomiting), and opioid cessation were recommended by a consensus opinion. Antiemetic and prokinetic agents were also considered potentially beneficial. This consensus offers a global perspective on idiopathic gastroparesis.

Treatment of dyspeptic symptoms with YamatoGast. A non-interventional study of a registered traditional herbal Rikkunshito extract product from Japanese Kampo Medicine in routine practice in Germany

INTRODUCTION

Dyspeptic symptoms belong to the most frequent reasons to seek medical advice and are a burden both for the individual affected and the healthcare system. In Japan, the traditional herbal Kampo prescription rikkunshito has proven benefit for this indication.

METHODS

In a prospective, multicentre, non-interventional study (NIS), the effectiveness, safety, and tolerability of a two-week treatment with the registered rikkunshito extract product YamatoGast was assessed in German patients with an acute episode of dyspeptic symptoms of functional origin under real-world conditions. The primary endpoint was the responsiveness to treatment assessed by the overall treatment effect (OTE) score. Secondary endpoints were the change in severity of dyspeptic symptoms and the change in quality of life (QoL). Safety evaluation was based on reported adverse drug reactions, drug compliance, and ratings of tolerability by physicians and patients.

RESULTS

Sixty-six patients were enrolled (mean age 48.9 years, 74% females). The treatment was well tolerated and highly beneficial, as expressed by pronounced responder rates of 78.9% for the primary endpoint OTE. All secondary endpoints were also met. The severity of dyspeptic symptoms significantly improved by 62-77% compared to baseline, confirmed by a remarkable improvement of QoL. Significant symptom relief started from the third day of treatment onwards.

CONCLUSION

In this non-interventional study, two-week treatment with YamatoGast resulted in a significant improvement of dyspeptic symptoms and was associated with high patient response and satisfaction. YamatoGast was confirmed as a safe and clinically relevant therapeutic option for patients suffering upper gastrointestinal complaints in routine practice.

Epidemiology of functional dyspepsia and gastroparesis as diagnosed in Flemish-Belgian primary care: A registry-based study from the Intego database

BACKGROUND

Dyspepsia is a prevalent condition in the general population. Besides organic causes, the differential diagnosis of dyspepsia includes functional dyspepsia (FD) and gastroparesis (GP) which share similar pathophysiological mechanisms and clinical presentation. So far, no study investigated the prevalence of FD and GP in a primary care in Belgium.

METHODS

Data were obtained from Intego, a Flemish-Belgian general practice-based morbidity registration network. From 586,164 patients between 2000 and 2021, we selected patients with ICD-10 code for FD and GP. Patients with organic gastrointestinal diseases were excluded. We determined demographics and comorbidities of FD/GP. For prevalence and incidence calculation, we included those who consulted their general practitioners at least once in the given year. Pair-wise comparison was conducted to access the impact of comorbidities on risk of FD/GP.

KEY RESULTS

Between 2011 and 2021, the prevalence of FD/GP ranged from 1.03% to 1.21%. The incidence of FD/GP ranged from 109 to 142 per 100,000 adults. In total 5242 cases of FD/GP were identified. These cases shared commonly coexisting diagnoses of gastroesophageal reflux disease (18.8%), irritable bowel syndrome (17.1%), and chronic constipation (18.7%). Patients with somatization/anxiety/depression had significantly higher risk of FD/GP, compared to the control (OR 1.38, 95% CI 1.19-1.61, p < 0.01).

CONCLUSIONS AND INFERENCES

The prevalence (1.03%-1.21%) and incidence (109-142/100,000) of FD/GP in primary care over last decade appear to conflict with epidemiological research in the general population. The discrepancies suggest a potential lack of awareness of FD and GP among physicians and/or patients in Flemish-Belgium.

Exploring the serotonin-probiotics-gut health axis: A review of current evidence and potential mechanisms

Modulatory effects of serotonin (5-Hydroxytryptamine [5-HT]) have been seen in hepatic, neurological/psychiatric, and gastrointestinal (GI) disorders. Probiotics are live microorganisms that confer health benefits to their host. Recent research has suggested that probiotics can promote serotonin signaling, a crucial pathway in the regulation of mood, cognition, and other physiological processes. Reviewing the literature, we find that peripheral serotonin increases nutrient uptake and storage, regulates the composition of the gut microbiota, and is involved in mediating neuronal disorders. This review explores the mechanisms underlying the probiotic-mediated increase in serotonin signaling, highlighting the role of gut microbiota in the regulation of serotonin production and the modulation of neurotransmitter receptors. Additionally, this review discusses the potential clinical implications of probiotics as a therapeutic strategy for disorders associated with altered serotonin signaling, such as GI and neurological disorders. Overall, this review demonstrates the potential of probiotics as a promising avenue for the treatment of serotonin-related disorders and signaling of serotonin.

Nutrition and Disorders of Gut-Brain Interaction

BACKGROUND

Disorders of gut-brain interaction (DGBIs) have a complex pathophysiology that is often characterized by a relationship between food ingestion and triggering of symptoms. Understanding of the underlying mechanisms and the role of nutrients as a therapeutic target are rapidly evolving.

AIMS AND METHODS

We performed a narrative review of the literature using the following keywords, their acronyms, and their associations: nutrients, disorders of gut-brain interaction; functional dyspepsia; malabsorption; irritable bowel syndrome; diarrhea; constipation.

RESULTS

Functional dyspepsia displayed a significant correlation between volume, fat and/or wheat abundance, chemical composition of ingested food and symptoms of early satiety, fullness and weight loss. Carbohydrate malabsorption is related to enzyme deficiency throughout the GI tract. Food composition and richness in soluble vs. non-soluble fibers is related to constipation and diarrhea. The elimination of fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) has a significant and non-unidirectional impact on irritable bowel syndrome (IBS) symptoms.

CONCLUSIONS

Food volume, nutritive and chemical composition, and its malabsorption are associated with symptom generation in DGBIs. Further multicenter, randomized-controlled clinical trials are needed to clarify the underlying pathophysiology.

Prevalence of delayed gastric emptying in patients with gastroparesis-like symptoms

BACKGROUND

The European consensus defined gastroparesis as a condition characterised by delayed gastric emptying (GE) in the absence of mechanical obstruction, with a symptom pattern of predominant nausea and/or vomiting and overlapping postprandial distress syndrome (PDS). The distinction between patients with gastroparesis and those with functional dyspepsia (FD), another gastrointestinal condition characterised by predominant PDS or epigastric pain syndrome symptoms, is ongoing.

AIM

To investigate the extent that symptom patterns may differentiate gastroparesis from FD.

METHODS

This retrospective study included 637 patients from Leuven University Hospital in 2006-2021 who had upper gastrointestinal symptoms, underwent a GE test, and completed the Dyspepsia Symptom Severity (DSS) questionnaire. Patients were identified as with gastroparesis-like symptoms (GPLS; i.e., moderate to severe nausea with moderate to severe PDS) or FD symptoms (not fitting GPLS). We excluded patients aged <18 years, and those with diabetes, organic gastrointestinal disease or a history of abdominal surgeries. Demographic and clinical variables were compared.

RESULTS

Among 545 patients, 238 reported GPLS and 307 reported FD symptoms. Those with GPLS had a significantly higher prevalence of delayed GE (half emptying time (T1/2) ≥109 min) and lower body mass index than those with FD (33.2% vs 17.6%, p < 0.01; 19.9 vs 21.2, p < 0.01, respectively). Among GPLS patients, those with delayed GE had higher DSS than those without (13.0 vs 12.0, p < 0.01).

CONCLUSIONS

In tertiary care patients who reported gastroparesis or FD symptoms, the presence of delayed GE was associated with GPLS. In patients with GPLS, delayed GE was associated with higher symptom severity.

Review article: An analysis of the pharmacological rationale for selecting drugs to inhibit vomiting or increase gastric emptying during treatment of gastroparesis

BACKGROUND

Drugs which can inhibit nausea/vomiting and/or increase gastric emptying are used to treat gastroparesis, mostly 'off-label'. Within each category, they act at different targets and modulate different physiological mechanisms.

AIMS

Address the questions: In gastroparesis, why should blocking one pathway causing vomiting, be more appropriate than another? Why might increasing gastric emptying via one mechanism be more appropriate than another?

METHODS

Drugs used clinically were identified via consensus opinions and reviews, excluding the poorly characterised. Their pharmacology was defined, mapped to mechanisms influencing vomiting and gastric emptying, and rationale developed for therapeutic use.

RESULTS

Vomiting: Rationale for 5-HT₃ , D₂ , H₁ or muscarinic antagonists, and mirtazapine, amitriptyline, nortriptyline, are poor. Arguments for inhibiting central consequences of vagal afferent transmission by NK₁ antagonism are complicated by doubts over effects on nausea. Gastric emptying: Confusion emerges because of side-effects of drugs increasing gastric emptying: Metoclopramide (5-HT₄ agonist, D₂ and 5-HT₃ antagonist; also blocks some emetic stimuli and causes tardive dyskinesia) and Erythromycin (high-efficacy motilin agonist, requiring low doses to minimise side-effects). Limited trials with selective 5-HT₄ agonists indicate variable efficacy.

CONCLUSIONS

Several drug classes inhibiting vomiting have no scientific rationale. NK₁ antagonism has rationale but complicated by limited efficacy against nausea. Studies must resolve variable efficacy of selective 5-HT₄ agonists and apparent superiority over motilin agonists. Overall, lack of robust activity indicates a need for novel approaches targeting nausea (e.g., modulating gastric pacemaker or vagal activity, use of receptor agonists or new targets such as GDF15) and objective assessments of nausea.

Research trends in the field of the gut-brain interaction: Functional dyspepsia in the spotlight – An integrated bibliometric and science mapping approach

Objectives

This study aims to perform a bibliometric analysis of functional dyspepsia (FD), which includes visualizing bibliographic information, in order to identify prevailing study themes, topics of interest, contributing journals, countries, institutions, and authors as well as co-citation patterns.

Methods

The Web of Science™ Core Collection Database was used to retrieve all peer-reviewed scientific publications related to FD research. The validated search terms were entered into the “title” and “author keywords” fields, and the results were sorted by publication year from 2006 to 2022. There were no restrictions on language. On 12 February 2023, a manual export of the complete metadata for each original publication and review article was performed. CiteSpace was used to reveal co-authorship, publication, and co-citation patterns to find prominent authors, organizations, countries, and journals in FD research as well as to identify author keywords with strong citation bursts, which could indicate an emerging research area. VOSviewer was used to build the co-occurrence indicator (co-word) to identify the main author keywords on which previous studies focused and to induce clustered scientific landscape for two consecutive periods to identify intriguing areas for future research.

Results

A search of the database retrieved 2,957 documents. There was a wave-like pattern in the number of publications until 2017, after which there was a spike in publication volume. The USA, China, and Japan provided the majority of contributions. In terms of institution, Mayo Clin, Univ Newcastle, and Katholieke Univ Leuven were found to be the prolific institutions. Additionally, the results indicate that eastern Asian researchers contributed significantly to the global knowledge of literature that led other countries; however, Canada, the USA, Australia, England, and Germany were found to have the highest degree of betweenness centrality. Nicholas J. Talley, Jan Tack, Gerald Holtmann, Michael Camilleri, Ken Haruma, and Paul Moayyedi occupied the top positions based on productivity and centrality indicators. Six thematic clusters emerged (Helicobacter pylori infection; pathophysiological mechanisms of FD; extraintestinal co-morbidities and overlap syndromes associated with FD; herbal medicine in FD; diabetic gastroparesis; and dietary factors in FD). “Acupuncture,” “duodenal eosinophilia,” “gut microbiota,” and others were among the author keywords with rising prevalence.

Conclusion

In FD research, eastern Asian countries have established themselves as major contributors with the highest publishing productivity; however, research has primarily been driven by North America, Europe, and Australia, where cooperation is generally more active and highly influential scientific results are produced. Our analysis suggests that increased investments, training of human resources, improved infrastructures, and expanded collaborations are essential to improving the quality of FD research in Asia. The emerging author keyword analysis suggests that eosinophil-mast cell axis, gut microbiota, mental disorders, and acupuncture are the key areas that attract researchers’ attention as future research boulevards. There is a highly skewed distribution of research output across Asia, with most focus on complementary and alternative medicine (CAM) coming from Chinese, Japanese, and South Korean centers. However, CAM remains an underexplored area of research in the context of FD, and it deserves greater research efforts in order to obtain quality scientific evidence. Furthermore, we propose that the research framework of CAM should not be limited to dysmotility; rather, it could be interpreted within a more holistic context that includes the brain-gut-microbiota axis, as well as novel concepts such as duodenitis, increased mucosal permeability, and infiltration and activation of eosinophils and mast cells, among others. Overall, we provided bibliometrics-based overviews of relevant literature to researchers from different backgrounds and healthcare professionals to provide an in-depth overview of major trends in FD research.

Lactobacillus rhamnosus GG supplementation on eradication rate and dyspepsia in Helicobacter pylori infection treated with three-in-one bismuth quadruple therapy

Introduction

Helicobacter pylori (Hp)-related dyspepsia has been related to gastroduodenal dysbiosis. The role of probiotic supplementation in the clinical management of Hp infection has been the object of several studies in terms of improvement of efficacy and tolerability of eradication treatments but data on their effects on the outcomes of post-eradication dyspepsia are lacking. The aim of the present study was to evaluate the influence of Lactobacillus rhamnosus GG (LGG) supplementation on bismuth quadruple therapy (BQT) in the clinical management of Hp-related infection both in terms of efficacy and tolerability and persistence of post-treatment dyspepsia.

Methods

A total of 164 (121 women) Hp-positive adult patients were enrolled in this pilot study and assigned to two different treatment regimens: group A received BQT for 10 days (three capsules qid, IPP bid) and group B received BQT for 10 days in combination with 6 × 109CFU LGG (ATCC53103) taken for 24 days (7 days before, 10 days during, and 7 days after therapy). Eradication was assessed after 45 days using the 13C-urea breath test (13C-UBT). Dyspepsia, distinguished into postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS), was assessed at the time of enrollment and 6 months after eradication.

Results

Approximately 98 patients were enrolled in group A and 66 patients in group B. At the enrollment, dyspepsia was present in 76.5% of group A and 86.5% of group B. No significant differences were observed in eradication rate between the 2 groups, both in intention-to-treat (ITT) analysis (82.3 vs. 75.0%) and per-protocol (PP) analysis (95 vs. 96%), and in the presence of side effects during the treatment (70.6 vs. 65.4%). At 6 months after eradication of Hp infection, the persistence of dyspepsia was statistically higher in patients of group A than in group B (38.8 vs. 16.1%; p = 0.032). The positive influence of LGG supplementation in improving post-eradication dyspepsia resulted in statistically more effectiveness in PDS dyspepsia, whose remission was 41.7% in group A and 84% in group B patients (p = 0.011).

Conclusion

In conclusion, LGG supplementation during Hp eradication therapy, even if not affecting eradication rates and therapy-related side effects, significantly impacts the remission of dyspepsia.

Diagnostic yield of upper gastrointestinal endoscopy in patients attending a UK centre with symptoms compatible with Rome IV functional dyspepsia

Background

Dyspeptic symptoms are common and mainly due to functional dyspepsia (FD). The Rome IV criteria mandate a normal upper gastrointestinal (UGI) endoscopy before diagnosing FD. However, endoscopies are costly, resource-intensive procedures that generate substantial waste. Hence, simpler means of diagnosing FD are desirable.

Objectives

To determine what proportion of UGI endoscopies are represented by patients with symptoms compatible with Rome IV FD, and the diagnostic yield in this cohort stratified according to alarm features.

Methods

Adult patients attending a UK centre for outpatient UGI endoscopy completed a preprocedure questionnaire on demographics, medical history, alarm features, mood, somatisation and GI symptoms. Alarm features were defined as age ≥55 years, dysphagia, anaemia, unintentional weight loss, UGI bleed or a family history of UGI cancer. Clinically significant endoscopic findings were cancers, Barrett's oesophagus, erosive oesophagitis, peptic ulcers or strictures.

Results

Of 387 patients attending for an outpatient non-surveillance diagnostic UGI endoscopy, 221 had symptoms compatible with FD whereas 166 did not. Approximately 80% in both groups had alarm features, with a similar prevalence of clinically significant endoscopic findings at ~10%. UGI endoscopy was normal in a cohort of 9% (n=35) with symptoms compatible with FD and no alarm features, while benign peptic ulcer was noted in two of 29 cases without FD symptoms and no alarm features.

Conclusion

1-in-10 UGI endoscopies are performed in patients with symptoms compatible with FD and no alarm features, in whom there is no diagnostic yield. We recommend such patients receive a positive diagnosis of FD without endoscopy.

British Society of Gastroenterology guidelines on the management of functional dyspepsia

Functional dyspepsia (FD) is a common disorder of gut-brain interaction, affecting approximately 7% of individuals in the community, with most patients managed in primary care. The last British Society of Gastroenterology (BSG) guideline for the management of dyspepsia was published in 1996. In the interim, substantial advances have been made in understanding the complex pathophysiology of FD, and there has been a considerable amount of new evidence published concerning its diagnosis and classification, with the advent of the Rome IV criteria, and management. The primary aim of this guideline, commissioned by the BSG, is to review and summarise the current evidence to inform and guide clinical practice, by providing a practical framework for evidence-based diagnosis and treatment of patients. The approach to investigating the patient presenting with dyspepsia is discussed, and efficacy of drugs in FD summarised based on evidence derived from a comprehensive search of the medical literature, which was used to inform an update of a series of pairwise and network meta-analyses. Specific recommendations have been made according to the Grading of Recommendations Assessment, Development and Evaluation system. These provide both the strength of the recommendations and the overall quality of evidence. Finally, in this guideline, we consider novel treatments that are in development, as well as highlighting areas of unmet need and priorities for future research.

Wei-Tong-Xin ameliorates functional dyspepsia via inactivating TLR4/MyD88 by regulating gut microbial structure and metabolites

BACKGROUND

Wei-Tong-Xin (WTX) is a traditional Chinese medicine (TCM) that has been screened and improved in accordance with the famous ancient Chinese formula "Wan Ying Yuan". It has been shown to be clinically effective in treating gastric dysmotility, but its underlying molecular mechanism remains unclear.

PURPOSE

This study primarily dealt with the effects and mechanisms of WTX on functional dyspepsia (FD) induced by chemotherapeutic drug cisplatin (CIS).

METHODS

Firstly, the UPLC fingerprint and multi-component determination of WTX were established. In vivo, gastrointestinal motility of mice was detected by charcoal propulsion test. Besides, H&E, western blot and qRT-PCR were performed to evaluate the occurrence of gastric antral inflammation. ROS-DHE staining was used to detect ROS levels. Further, the gut microbiota were subjected to sequencing by 16S rRNA, and the levels of bacterial metabolites short-chain fatty acids (SCFAs) and lipopolysaccharide (LPS) were detected by GC-MS and Limulus kits, respectively. The levels of GLP-1 in gastric antrum were assessed by ELISA kits. Finally, siRNA-FFAR2 experiment was performed in Raw 264.7 cells.

RESULTS

23 common peaks were obtained from the UPLC fingerprint, and the content of 10 target components was determined. WTX increased the relative abundance of Firmicutes and decreased the number of Verrucomicrobia, accompanied by changes in the levels of SCFAs and LPS. By mediating the expression changes of free fatty acid receptor 2 (FFAR2) and toll-like receptor 4 (TLR4), WTX inhibited the phosphorylation of nuclear factor-κB (NF-κB), JNK and P38, decreased the levels of IL-1β, inducible nitric oxide synthase (iNOS) and ROS, increased the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), IL-4 and arginase-1 (Arg-1). Decreased expressions of glucagon-like peptide 1 (GLP-1) induced by WTX promoted gastric motility in FD mice. In vitro, siRNA-FFAR2 of Raw 264.7 cells eliminated the effects of WTX on TLR4 signaling pathway.

CONCLUSIONS

In this study, the chemical profile of WTX was first reported. Based on remodeling the gut microbiota structure and adjusting the levels of metabolites (SCFAs and LPS), WTX inactivated the TLR4/MyD88 signaling pathway to inhibit the occurrence of gastric antral inflammation, which reversed the inhibitory effect of GLP-1 on gastric motility, and improved CIS-induced FD symptoms.

Exclusion Diets in Functional Dyspepsia

Functional dyspepsia represents one of the most common and prevalent disorders of the brain-gut interaction, with a large number of widespread risk factors being identified. With an intricate pathogenesis and symptomatology, it heavily impacts the quality of life and, due to the limited efficacy of traditional pharmacological agents, patients are likely to seek other medical and non-medical solutions to their problem. Over the last few years, significant research in this domain has emphasized the importance of various psychological therapies and nutritional recommendations. Nevertheless, a correlation has been established between functional dyspepsia and food intolerances, with more and more patients adopting different kinds of exclusion diets, leading to weight loss, restrictive eating behaviour and an imbalanced nutritional state, further negatively impacting their quality of life. Thus, in this systematic review, we aimed at analysing the impact and efficiency of certain exclusion diets undertook by patients, more precisely, the gluten-free diet and the low-FODMAP diet.

Immune Activation in Functional Dyspepsia: Bystander Becoming the Suspect

Disorders of gut-brain interaction (DGBI), formerly termed functional gastrointestinal disorders (FGID), are highly prevalent although exact pathophysiological mechanisms remain unclear. Intestinal immune activation has been recognized, but increasing evidence supports a pivotal role for an active inflammatory state in these disorders. In functional dyspepsia (FD), marked eosinophil and mast cell infiltration has been repeatedly demonstrated and associations with symptoms emphasize the relevance of an eosinophil-mast cell axis in FD pathophysiology. In this Review, we highlight the importance of immune activation in DGBI with a focus on FD. We summarize eosinophil biology in both homeostasis and inflammatory processes. The evidence for immune activation in FD is outlined with attention to alterations on both cellular and molecular level, and how these may contribute to FD symptomatology. As DGBI are complex and multifactorial conditions, we shed light on factors associated to, and potentially influencing immune activation, including bidirectional gut-brain interaction, allergy and the microbiota. Crucial studies reveal a therapeutic benefit of treatments targeting immune activation, suggesting that specific anti-inflammatory therapies could offer renewed hope for at least a subset of DGBI patients. Lastly, we explore the future directions for DGBI research that could advance the field. Taken together, emerging evidence supports the recognition of FD as an immune-mediated organic-based disorder, challenging the paradigm of a strictly functional nature.