Pathophysiology of Functional Gastrointestinal Disorders: A Holistic Overview

A multifaceted ecological approach to explore links between environmental factors and the epidemiology of disorders of gut-brain interaction

BACKGROUND

Disorders of gut-brain interaction (DGBI) are characterized by debilitating symptoms not explained by structural or biochemical abnormalities. While functional conditions present with complex, likely heterogeneous pathophysiology, we aimed to investigate if proxy measures of sociocultural and environmental factors are associated with the prevalence of various DGBI in populations across the world.

METHODS

We performed an ecological study utilizing peer-reviewed published datasets reporting for 26 countries prevalence rates of DGBI (Rome Foundation Global Epidemiology Study, RFGES), with six independent variables: Helicobacter pylori prevalence and household size as proxy measures for orofecal infections, gross domestic product per capita (GDP), and median age as a proxy measures for socioeconomic development, density of fast food outlets (FFO) per 100,000 population as proxy measure for processed food exposure, and suicide mortality rate per 100,000 people, and world happiness scores were used as a proxy for psychological stress. The data were retrieved from publicly accessible datasets (United Nations, CIA World Factbook, World Bank, World Happiness Report, commercial/financial reports of a global FFO chain). We used linear regression to assess variables in univariate and multivariate analysis and report standardized β coefficients with 95% confidence intervals (CI).

KEY RESULTS

The regression model revealed that the overall prevalence of DGBI was inversely associated with both GDP per capita (β = -0.57, 95% CI: -0.92, -0.22, p = 0.002) and happiness scores (β = -0.433 95% CI: 0.821, -0.065, p = 0.023), while being positively associated with H. pylori prevalence (β = 0.40, 95% CI: 0.008, 0.81, p = 0.046). The prevalence of functional constipation (FC) was also inversely associated with GDP per capita (β = -0.50, 95% CI: -0.86, -0.13, p = 0.01) and happiness scores (β = -0.497, 95% CI: -0.863, -0.132, p = 0.01), while being positively associated with H. pylori prevalence (β = 0.53, 95% CI: 0.16, 0.91, p = 0.007). The Multivariate model analysis revealed that combining the factors of H. pylori prevalence, suicide rate, household size and happiness scores showed statistically significant association with FC (p = 0.039). Household size (β = -0.43, 95% CI: -0.82, 0.038, p = 0.033) and suicide rates (β = 0.55, 95% CI: 0.19, 0.90, p = 0.004) were statistically significantly associated with functional diarrhea. Irritable bowel syndrome (IBS) was associated with GDP per capita (β = -0.40, 95% CI: -0.79, -0.014, p = 0.043) and happiness scores (β = -0.390, 95% CI: -0.778, -0.003, p = 0.049).

CONCLUSIONS & INFERENCES

Utilizing publicly available data, the prevalence of DGBI across diverse countries is linked to various socio-cultural and environmental factors. Collectively, the data suggests that the prevalence of DGBI is increased in less prosperous regions of the world.

Revolutionizing Gastrointestinal Disorder Management: Cutting-Edge Advances and Future Prospects

In recent years, remarkable strides have been made in the management of gastrointestinal disorders, transforming the landscape of patient care and outcomes. This article explores the latest breakthroughs in the field, encompassing innovative diagnostic techniques, personalized treatment approaches, and novel therapeutic interventions. Additionally, this article emphasizes the use of precision medicine tailored to individual genetic and microbiome profiles, and the application of artificial intelligence in disease prediction and monitoring. This review highlights the dynamic progress in managing conditions such as inflammatory bowel disease, gastroesophageal reflux disease, irritable bowel syndrome, and gastrointestinal cancers. By delving into these advancements, we offer a glimpse into the promising future of gastroenterology, where multidisciplinary collaborations and cutting-edge technologies converge to provide more effective, patient-centric solutions for individuals grappling with gastrointestinal disorders.

The role of the gut microbiome in disorders of gut-brain interaction

Disorders of Gut-Brain Interaction (DGBI) are widely prevalent and commonly encountered in gastroenterology practice. While several peripheral and central mechanisms have been implicated in the pathogenesis of DGBI, a recent body of work suggests an important role for the gut microbiome. In this review, we highlight how gut microbiota and their metabolites affect physiologic changes underlying symptoms in DGBI, with a particular focus on their mechanistic influence on GI transit, visceral sensitivity, intestinal barrier function and secretion, and CNS processing. This review emphasizes the complexity of local and distant effects of microbial metabolites on physiological function, influenced by factors such as metabolite concentration, duration of metabolite exposure, receptor location, host genetics, and underlying disease state. Large-scale in vitro work has elucidated interactions between host receptors and the microbial metabolome but there is a need for future research to integrate such preclinical findings with clinical studies. The development of novel, targeted therapeutic strategies for DGBI hinges on a deeper understanding of these metabolite-host interactions, offering exciting possibilities for the future of treatment of DGBI.

Defining a vitamin A5/X specific deficiency - vitamin A5/X as a critical dietary factor for mental health

A healthy and balanced diet is an important factor to assure a good functioning of the central and peripheral nervous system. Retinoid X receptor (RXR)-mediated signaling was identified as an important mechanism of transmitting major diet-dependent physiological and nutritional signaling such as the control of myelination and dopamine signalling. Recently, vitamin A5/X, mainly present in vegetables as provitamin A5/X, was identified as a new concept of a vitamin which functions as the nutritional precursor for enabling RXR-mediated signaling. The active form of vitamin A5/X, 9-cis-13,14-dehydroretinoic acid (9CDHRA), induces RXR-activation, thereby acting as the central switch for enabling various heterodimer-RXR-signaling cascades involving various partner heterodimers like the fatty acid and eicosanoid receptors/peroxisome proliferator-activated receptors (PPARs), the cholesterol receptors/liver X receptors (LXRs), the vitamin D receptor (VDR), and the vitamin A(1) receptors/retinoic acid receptors (RARs). Thus, nutritional supply of vitamin A5/X might be a general nutritional-dependent switch for enabling this large cascade of hormonal signaling pathways and thus appears important to guarantee an overall organism homeostasis. RXR-mediated signaling was shown to be dependent on vitamin A5/X with direct effects for beneficial physiological and neuro-protective functions mediated systemically or directly in the brain. In summary, through control of dopamine signaling, amyloid β-clearance, neuro-protection and neuro-inflammation, the vitamin A5/X - RXR - RAR - vitamin A(1)-signaling might be "one of" or even "the" critical factor(s) necessary for good mental health, healthy brain aging, as well as for preventing drug addiction and prevention of a large array of nervous system diseases. Likewise, vitamin A5/X - RXR - non-RAR-dependent signaling relevant for myelination/re-myelination and phagocytosis/brain cleanup will contribute to such regulations too. In this review we discuss the basic scientific background, logical connections and nutritional/pharmacological expert recommendations for the nervous system especially considering the ageing brain.

Relationship between gastrointestinal symptoms and COVID-19 infection in the pediatric population: a scoping review

OBJECTIVE

To map the evidence in the literature about the relationship between gastrointestinal symptoms and COVID-19 in the pediatric population.

METHOD

This is a scoping review following the recommendations of the Joanna Briggs Institute and PRISMA Extension for Scoping Reviews (PRISMA-ScR): Checklist and Explanation. The search was carried out on the following bases: Embase, Google Scholar, PubMed, Scopus, LILACS, CINAHL, Scielo, Web of Science and Virtual Health Library Portal, between July and August 2023. Original studies available in full, in any language, were included.

RESULTS

Ten studies were chosen that pointed to three premises: (1) the ACE2 receptor is found in the epithelial cells of the gastrointestinal tract; (2) gastrointestinal symptoms are mediated by stress and infection is justified by the gut-brain axis; (3) it develops the process of Multisystem Inflammatory Syndrome in children, affecting the gastrointestinal tract.

CONCLUSION

The synthesis of evidence provided three assumptions which guide the origin of gastrointestinal symptoms. The identification of gastrointestinal symptoms in children affected by COVID-19 can assist in the clinical approach and management of care and treatments.

Screening for functional gastrointestinal disorders in preterm infants up to 12 months of corrected age: a prospective cohort study

Functional gastrointestinal disorders (FGIDs) are characterized by a variety of symptoms that are frequently age-dependent, chronic, or recurrent and are not explained by structural or biochemical abnormalities. There are studies in the literature reporting different results regarding the relationship between prematurity and FGIDs. The main objective of this study was to compare the frequency of FGIDs between preterm and term infants. The secondary objective was to evaluate whether there was any association between neonatal characteristics and development of FGIDs. A multicenter prospective cohort study that included preterm infants born before 37 weeks of gestation and healthy term infants was carried out. At 1, 2, 4, 6, 9, and 12 months of age, infants were assessed for the presence of FGIDs using the Rome IV criteria. In preterm infants, an additional follow-up visit was made at 12 months corrected age. 134 preterm and 104 term infants were enrolled in the study. Infantile colic, rumination syndrome, functional constipation, and infant dyschezia were more common in preterm infants. Incidence of other FGIDs (infant regurgitation, functional diarrhea and cyclic vomiting syndrome) were similar among preterm and term infants. Preterm infants who are exclusively breastfeed in the first 6 months of life have a lower incidence of infantile colic (18.8% vs 52.1%, p = 0.025). In terms of chronological age, FGIDs symptoms started later in preterm infants; this difference was statistically significant for infantile colic and regurgitation (median age 2 months vs 1 month, p < 0.001).   Conclusions: Preterm infants have a higher prevalence of FGIDs compared with term controls. Therefore, especially if they have gastrointestinal complaints, they should be screened for FGIDs. Possibly due to maturational differences, the time of occurrence of FGIDs may differ in preterm infants. Infantile colic incidence decreases with exclusive breastfeeding. What is Known: • The functional gastrointestinal disorders are a very common in infancy. • Data on preterm infants with FGIDs are currently very limited. What is New: • Preterm infants have a higher incidence of infantile colic, rumination syndrome, functional constipation and infant dyschezia when compared to term infants. • Preterm infants who are exclusively breastfed during the first 6 months of life experience a lower incidence of infantile colic.

Targeted metabolomics revealed the mechanisms underlying the role of Liansu capsule in ameliorating functional dyspepsia

ETHNOPHARMACOLOGICAL RELEVANCE

Liansu capsule could alleviate dyspeptic symptoms; however, the mechanisms underlying its role in treating functional dyspepsia (FD) remain unclear.

AIM OF THE STUDY

To elucidate the mechanism underlying the efficacy of Liansu capsule in alleviating FD symptoms.

MATERIALS AND METHODS

Thirty-six male mice were randomly divided into the following six groups: control, model, low-strength Liansu, moderate-strength Liansu, high-strength Liansu, and domperidone groups. Small intestine propulsion rate, gastric residual rate and histopathological analysis were performed to evaluate efficacy of Liansu capsule. Levels of interleukin-1β, interleukin-6, tumor necrosis factor α, phosphorylation of p65, ghrelin and gastrin were verified by real-time quantitative polymerase chain reaction and immunofluorescence assays. Targeted metabolomic analyses, western blotting and immunofluorescence assays were used to explore the mechanism of Liansu capsule in ameliorating FD.

RESULTS

The Liansu capsule significantly ameliorated the symptoms of FD, and markedly increased the levels of ghrelin and gastrin. Moreover, Liansu capsule significantly downregulated the levels of the proinflammatory cytokine interleukin-1β, interleukin-6, tumor necrosis factor α, and inhibited the phosphorylation of p65. Targeted metabolomic analyses showed that Liansu capsule significantly reduced the levels of deoxycholic acid and hyodeoxycholic acid, which were significantly elevated in the model group. Furthermore, these results showed that deoxycholic acid and hyodeoxycholic acid markedly promoted the levels of Takeda G-protein-coupled receptor 5 (TGR5), phosphorylated signal transducer and activator of transcription 3 (STAT3), and Kruppel-like factor 5 (KLF5) in vitro. whereas, Liansu capsule significantly reduced the levels of TGR5, phosphorylated STAT3, and KLF5.

CONCLUSION

Our findings indicated that Liansu capsule improved FD by regulating the deoxycholic acid/hyodeoxycholic acid-TGR5-STAT3-KLF5 axis. The findings reveal a novel mechanism underlying the role of Liansu capsule, which may be a promising therapeutic strategy for FD.

Exploring the Interconnections of Functional Gut Disorders and Inflammatory Bowel Disease: A Narrative Review Article

This review reveals details of the interaction between disorders of gut-brain interaction (DGBI) and inflammatory bowel disease (IBD) by providing an in-depth review of that relationship. The review provides a nuanced understanding of this multifaceted dynamic by spanning shared symptomatology, the impact of inflammation on functional aspects, and addressing diagnostic challenges, psychological influences, treatment strategies, and emerging research directions. By synthesizing current knowledge and identifying gaps in understanding, this article aims to contribute to the evolving discourse surrounding the interplay between IBD and DGBI, offering valuable insights for clinicians, researchers, and healthcare professionals navigating the complexities of gastrointestinal health.

A Mendelian randomization study on the effects of plasma lipids on irritable bowel syndrome and functional dyspepsia

Although functional gastrointestinal disorder (FGID) is a common clinical condition, its risk factors remain unclear. We performed a Mendelian randomization study to explore the association between plasma lipids and the risk of FGID. Instrumental variables closely related to six plasma lipids were obtained from the corresponding genome-wide association studies, and summary-level data on FGID, including irritable bowel syndrome (IBS) and functional dyspepsia (FD), were extracted from the FinnGen study. The primary inverse variance weighted method and other supplementary analyses were used to evaluate the causal relationship between diverse plasma lipids and FGID. For each increase in the standard deviation of triglyceride levels, there was a 12.0% increase in the risk of IBS rather than that of FD. Low- and high-density lipoprotein cholesterol, total cholesterol, apolipoprotein A, and apolipoprotein B levels were not associated with the risk of IBS or FD. Through this study, we identified the causal role of triglycerides in the pathogenesis of IBS, which could benefit further basic and clinical research.

Si-Ni-San reverses dietary fat absorption defects in a murine model of depression

Depression is often associated with fatigue/energy loss. However, we lack a detailed understanding of the factors explaining this association. In this study, we uncovered that depressed mice have a defect in fat absorption, resulting in weight loss and reduced circulating lipid levels. Si-Ni-San (SNS), a basic formula of traditional Chinese medicine (TCM) for the treatment of depression, was found to not only alleviate depression-like behaviors, but also reverse the weight loss and dietary fat absorption of depressed mice. We found that SNS improved body weight and circulating lipid levels of depressed mice by up-regulating proteins [such as FFA uptake protein (CD36), TAG synthesis proteins (GPAT3, MOGAT2, DGAT1 and DGAT2) and chylomicron packaging proteins (MTP and APOB)] in the fat absorption pathway. Furthermore, cell-based results conducted with LPS-stimulated mouse MODE-K and human Caco-2 cells support that SNS, as well as Sinensetin (SIN) and Nobiletin (NOB), the two active components of the formula, have a role in regulating lipid absorption. Mechanistic studies revealed that SNS reverses body weight and fat absorption defects of depressed mice in part through the NR1D1/BMAL1/DGAT2 axis. These findings advance our understanding of the crosstalk between depression and energy loss, highlight the importance of gut function in disease management, and provide a basis for the application of SNS in the clinical treatment of depression and related disorders.

Myths and Facts about Food Intolerance: A Narrative Review

Most adverse reactions to food are patient self-reported and not based on validated tests but nevertheless lead to dietary restrictions, with patients believing that these restrictions will improve their symptoms and quality of life. We aimed to clarify the myths and reality of common food intolerances, giving clinicians a guide on diagnosing and treating these cases. We performed a narrative review of the latest evidence on the widespread food intolerances reported by our patients, giving indications on the clinical presentations, possible tests, and dietary suggestions, and underlining the myths and reality. While lactose intolerance and hereditary fructose intolerance are based on well-defined mechanisms and have validated diagnostic tests, non-coeliac gluten sensitivity and fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) intolerance are mainly based on patients' reports. Others, like non-hereditary fructose, sorbitol, and histamine intolerance, still need more evidence and often cause unnecessary dietary restrictions. Finally, the main outcome of the present review is that the medical community should work to reduce the spread of unvalidated tests, the leading cause of the problematic management of our patients.

Assesment of functional gastrointestinal diseases in obese children

Functional gastrointestinal disorders (FGID) are disorders of gut-brain interactions characterized by chronic recurrent gastrointestinal symptoms and are reported to be more common in obese individuals. The aim of the study was to evaluate FGID in obese children. A total of 405 children (6-18 years) were enrolled in this cross sectional study. The children were divided into two groups according to body mass index (BMI) as < 85th percentile and > 95th percentile. Diagnosis of FGID was based on ROME VI criteria. Demographic and clinical characteristics of the patients were evaluated. FGID and subgroups were determined. The mean age of the children was 12.73 ± 3.17 years; 52% (n = 211) of them was female and 47.9% (n = 194) was male. A total of 50.6% patients had BMI > 95th percentile, and 55.1% of those patients had FGID. The subgroups of FGID, functional abdominal pain disorders and functional defecation disorders were significantly more common in obese children than non-obese group (P < 0.01). Additionally, constipation-predominant irritable bowel syndrome (IBS), diarrhea-predominant IBS, functional diarrhea, and abdominal distention were significantly more common in obese children than non-obese children (P < 0.01).

CONCLUSION

 FGID in obese children was found to be increased significantly. Assessment of functional gastrointestinal symptoms in obese children will prevent unnecessary examinations.

WHAT IS KNOWN

• Functional gastrointestinal disorders are reported to be more common in obese individuals.

WHAT IS NEW

• Functional abdominal pain disorders and functional defecation disorders were significantly more common in obese children than non-obese group. • Constipation-predominant irritable bowel syndrome (IBS), diarrhea-predominant IBS, functional diarrhea, and abdominal distention were significantly more common in obese children than non-obese children.

Treatment of functional dyspepsia in Chinese adult patients with domperidone: A multicenter, randomized, double-blind, placebo-controlled pilot study

OBJECTIVE

This pilot study aimed to evaluate the efficacy and safety of domperidone for the treatment of Chinese patients with functional dyspepsia (FD) who were diagnosed according to the Rome IV criteria and to identify the FD subtypes that potentially responded better to domperidone.

METHODS

This multicenter prospective study was conducted in China from August 2018 to July 2020, consisting of a 1-week screening phase and a 2-week double-blind treatment phase. Participants were randomized to receive domperidone 10 mg or matching placebo tablets thrice daily for 14 days. The primary end-point was the overall treatment effect (OTE) response rate after 2-week therapy.

RESULTS

Altogether 160 patients were included, with 80 patients in each group. The OTE response rate after 2-week therapy was significantly higher for domperidone compared with placebo (60.7% vs 46.0%; relative risk [RR] 1.318, 95% confidence interval [CI] 0.972-1.787). Moreover, the OTE response rate after 2-week domperidone or placebo treatment was 60.3% versus 54.9% for postprandial distress syndrome (PDS) (RR 1.098, 95% CI 0.750-1.607) and 60.6% versus 35.2% for overlapping PDS-epigastric pain syndrome (EPS) (RR 1.722, 95% CI 0.995-2.980). Adverse events were reported by seven patients in the domperidone group and 12 patients in the placebo group. None of the adverse events in the domperidone group were serious.

CONCLUSION

Domperidone showed a positive pattern regarding OTE response rates after 2-week therapy compared to placebo in patients with FD, as well as in subtypes of PDS and overlapping PDS-EPS. No new safety issue was observed.

Low fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet is associated with increased risk of uninvestigated chronic dyspepsia and its symptoms in adults

BACKGROUND

Assessing the potential effects of a low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) diet on functional gastrointestinal symptoms, particularly upper gastrointestinal symptoms, is not clearly understood. The current study aimed to explore the association of a diet low in FODMAPs with uninvestigated chronic dyspepsia (UCD) and functional dyspeptic symptoms in a large population of Iranian adults.

METHODS

This cross-sectional study was conducted on 2987 adults. Dietary FODMAPs intake estimated using a validated food-frequency questionnaire. UCD, early satiation, postprandial fullness and gastric pain were determined using a modified and validated version of the Rome III Questionnaire.

RESULTS

After controlling for various confounders, consumption of a diet low in FODMAPs was associated with increased risk of UCD in the whole population (OR=1.85; 95% CI: 1.23-2.78; P=0.009) and women (OR=2.41; 95% CI: 1.46-3.95; P=0.004), but not in men. Higher consumption of a low-FODMAPs diet was related to increased risk of postprandial fullness (OR=1.38; 95% CI: 1.08-1.78; P=0.046). The inverse association between FODMAPs and epigastric pain tended to be significant after controlling for eating behaviors (OR=1.31; 95% CI: 0.98-1.76; P=0.084). No significant association was observed for early satiation.

CONCLUSIONS

Our data suggest that consumption of a low-FODMAPs diet may increase the risk of UCD and postprandial fullness; however, well-planned randomized controlled trials and prospective cohorts are required to ascertain the effect of FODMAPs on upper gastrointestinal symptoms.

The Role of Ion Channels in Functional Gastrointestinal Disorders (FGID): Evidence of Channelopathies and Potential Avenues for Future Research and Therapeutic Targets

Several gastrointestinal (GI) tract abnormalities, including visceral hypersensitivity, motility, and intestinal permeability alterations, have been implicated in functional GI disorders (FGIDs). Ion channels play a crucial role in all the functions mentioned above. Hormones and natural molecules modulate these channels and represent targets of drugs and bacterial toxins. Mutations and abnormal functional expression of ion channel subunits can lead to diseases called channelopathies. These channelopathies in gastroenterology are gaining a strong interest, and the evidence of co-relationships is increasing. In this review, we describe the correlation status between channelopathies and FGIDs. Different findings are available. Among others, mutations in the ABCC7/CFTR gene have been described as a cause of constipation and diarrhea. Mutations of the SCN5A gene are instead associated with irritable bowel syndrome. In contrast, mutations of the TRPV1 and TRPA genes of the transient receptor potential (TRP) superfamily manifest hypersensitivity and visceral pain in sensory nerves. Recently, mice and humans affected by Cantu syndrome (CS), which is associated with the mutations of the KCNJ8 and ABCC9 genes encoding for the Kir6.1 and SUR2 subunits, showed dysfunction of contractility throughout the intestine and death in the mice after the weaning on solid food. The discovery of a correlation between channelopathies and FIGD opens new avenues for discovering new direct drug targets for specific channelopathies, leading to significant implications for diagnosing and treating functional GI diseases.

Perinatal high-fat diet exposure alters oxytocin and corticotropin releasing factor inputs onto vagal neurocircuits controlling gastric motility

Perinatal high-fat diet (pHFD) exposure alters the development of vagal neurocircuits that control gastrointestinal (GI) motility and reduce stress resiliency in offspring. Descending oxytocin (OXT; prototypical anti-stress peptide) and corticotropin releasing factor (CRF; prototypical stress peptide) inputs from the paraventricular nucleus (PVN) of the hypothalamus to the dorsal motor nucleus of the vagus (DMV) modulate the GI stress response. How these descending inputs, and their associated changes to GI motility and stress responses, are altered following pHFD exposure are, however, unknown. The present study used retrograde neuronal tracing experiments, cerebrospinal fluid extraction, in vivo recordings of gastric tone, motility and gastric emptying rates, and in vitro electrophysiological recordings from brainstem slice preparations to investigate the hypothesis that pHFD alters descending PVN-DMV inputs and dysregulates vagal brain-gut responses to stress. Compared to controls, rats exposed to pHFD had slower gastric emptying rates and did not respond to acute stress with the expected delay in gastric emptying. Neuronal tracing experiments demonstrated that pHFD reduced the number of PVNOXT neurons that project to the DMV, but increased PVNCRF neurons. Both in vitro electrophysiology recordings of DMV neurons and in vivo recordings of gastric motility and tone demonstrated that, following pHFD, PVNCRF -DMV projections were tonically active, and that pharmacological antagonism of brainstem CRF1 receptors restored the appropriate gastric response to brainstem OXT application. These results suggest that pHFD exposure disrupts descending PVN-DMV inputs, leading to a dysregulated vagal brain-gut response to stress. KEY POINTS: Maternal high-fat diet exposure is associated with gastric dysregulation and stress sensitivity in offspring. The present study demonstrates that perinatal high-fat diet exposure downregulates hypothalamic-vagal oxytocin (OXT) inputs but upregulates hypothalamic-vagal corticotropin releasing factor (CRF) inputs. Both in vitro and in vivo studies demonstrated that, following perinatal high-fat diet, CRF receptors were tonically active at NTS-DMV synapses, and that pharmacological antagonism of these receptors restored the appropriate gastric response to OXT. The current study suggests that perinatal high-fat diet exposure disrupts descending PVN-DMV inputs, leading to a dysregulated vagal brain-gut response to stress.

Overlap of disorders of gut-brain interaction: a systematic review and meta-analysis

BACKGROUND

Rome criteria differentiate distinct types of disorders of gut-brain interaction (DGBI); also known as functional gastrointestinal disorders. Overlap of symptom categories frequently occurs. This systematic review and meta-analysis aimed to define the prevalence of DGBI overlap and compare overlap in population-based, primary care or tertiary care health settings. Furthermore, we aimed to compare symptom severity of psychological comorbidities in DGBI with and without overlap.

METHODS

For this systematic review and meta-analysis we searched MEDLINE (PubMed) and Embase electronic databases from inception until March 1, 2022, for original articles and conference abstracts of observational cross-sectional, case-controlled, or cohort design studies that reported the prevalence of DGBI overlap in adult participants (aged ≥18 years). We included only those studies where the diagnosis of DGBI was based on clinical assessment, questionnaire data, or specific symptom-based criteria. Studies were excluded if reporting on mixed populations of DGBI and organic diseases. Aggregate patient data were extracted from eligible published studies. The prevalence of DGBI overlap in all studies was pooled using the DerSimonian and Laird random effects model, and further analysis stratified by subgroups (care setting, diagnostic criteria, geographic region, and gross domestic product per capita). We also assessed the relationship between DGBI overlap with anxiety, depression, and quality of life symptom scores. This study was registered with PROSPERO (CRD42022311101).

FINDINGS

46 of 1268 screened studies, reporting on 75 682 adult DGBI participants, were eligible for inclusion in this systematic review and meta-analysis. Overall, 24 424 (pooled prevalence 36·5% [95% CI 30·7 to 42·6]) participants had a DGBI overlap, with considerable between-study heterogeneity (I²=99·51, p=0·0001). In the tertiary health-care setting, overlap among participants with DGBI was more prevalent (8373 of 22 617, pooled prevalence 47·3% [95% CI 33·2 to 61·7]) compared with population-based cohorts (11 332 of 39 749, pooled prevalence 26·5% [95% CI 20·5 to 33·4]; odds ratio 2·50 [95% CI 1·28 to 4·87]; p=0·0084). Quality of life physical component scores were significantly lower in participants with DGBI overlap compared with participants without overlap (standardised mean difference -0·47 [95% CI -0·80 to -0·14]; p=0·025). Participants with DGBI overlap had both increased symptom scores for anxiety (0·39 [95% CI 0·24 to 0·54]; p=0·0001) and depression (0·41 [0·30 to 0·51]; p=0·0001).

INTERPRETATION

Overlap of DGBI subtypes is frequent, and is more prevalent in tertiary care settings and associated with more severe symptom manifestations or psychological comorbidities. Despite the large sample size, the comparative analyses revealed substantial heterogeneity, and the results should be interpreted with caution.

FUNDING

National Health and Medical Research Council and Centre for Research Excellence.

Effects of a Low-FODMAP Diet on Irritable Bowel Syndrome in Both Children and Adults-A Narrative Review

Irritable bowel syndrome is a typical gastrointestinal disease that causes bloating, flatulence, abdominal pain, diarrhoea, constipation, or alteration of the last two in adults and children. A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) is one of the potential treatment strategies to reduce abdominal symptoms and increase the quality of life. The present narrative review aims to present a general overview of current studies that have evaluated the efficacy of a low-FODMAP diet against other diets in gastrointestinal symptoms, nutrient intake in adults and children, and lifestyle quality. The research was performed using seven searchable databases, which included the Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews (CDSR), Excerpta Medica Database (EMBASE), Medline, PubMed, Scopus, and Web of Science, up to March 2023. In conclusion, there is significant evidence that the follow-up of a low-FODMAP diet might be a feasible first-line therapeutic strategy to reduce stomach discomfort, pain, bloating, and quality of life for patients with irritable bowel syndrome.

Functional gastrointestinal disorders among healthcare professionals at a tertiary Australian hospital

Background and Aim

The aim of this study was to determine the frequency, characteristics, and associations of functional gastrointestinal disorders (FGIDs) among healthcare professionals.

Methods

A qualitative survey was conducted among the staff at a tertiary Australian hospital between January 2017 and June 2018. Rome III criteria (excluding endoscopic) were used to define FGID. Multivariable logistic regression was used to explore associations.

Results

Of the 274 respondents (17% doctors, 66% nurses, 17% others; 77% female), 54% had experienced GI symptoms ≥3 times per week and 23% were diagnosed with FGIDs (2% IBS, 19% FD, 2% both). GI symptoms were more common in females (58% vs. 38%), Caucasians versus Asians (59% vs. 35%), respondents who were easily (67% vs. 40%) or often stressed (58% vs. 37%), and had irregular working hours (62% vs. 46%, each P < 0.05). Independent predictors of GI symptoms included being easily stressed (OR 2.7) and female sex (OR 2.4), while Asian ethnicity was protective (OR 0.42, each P < 0.05). FGIDs were more prevalent in respondents who often felt stressed (27% vs. 10%), felt easily stressed (29% vs. 17%), and in nurses compared to others (27% vs. 16%; each P < 0.05). The only independent predictor of FGID was being often stressed (OR 4.1, P = 0.011).

Conclusions

FGIDs and GI symptoms are prevalent among hospital workers. Stress, female sex, irregular working hours, and non-Asian ethnicity appeared to be associated with GI symptoms and FGIDs.

Food, Dietary Patterns, or Is Eating Behavior to Blame? Analyzing the Nutritional Aspects of Functional Dyspepsia

Functional dyspepsia is a gastrointestinal disorder characterized by postprandial fullness, early satiation, epigastric pain, and epigastric burning. The pathophysiology of the disease is not fully elucidated and there is no permanent cure, although some therapies (drugs or herbal remedies) try to reduce the symptoms. Diet plays a critical role in either the reduction or the exacerbation of functional dyspepsia symptoms; therefore dietary management is considered to be of high importance. Several foods have been suggested to be associated with worsening functional dyspepsia, such as fatty and spicy foods, soft drinks, and others, and other foods are thought to alleviate symptoms, such as apples, rice, bread, olive oil, yogurt, and others. Although an association between functional dyspepsia and irregular eating habits (abnormal meal frequency, skipping meals, late-night snacking, dining out, etc.) has been established, not many dietary patterns have been reported as potential factors that influence the severity of functional dyspepsia. A higher adherence to Western diets and a lower adherence to FODMAPs diets and healthy patterns, such as the Mediterranean diet, can contribute to the worsening of symptoms. More research is needed on the role of specific foods, dietary patterns, or specific eating habits in the management of functional dyspepsia.

Emotional-Single Prolonged Stress: A promising model to illustrate the gut-brain interaction

Excessive stress can precipitate depression and anxiety diseases, and damage gastrointestinal functionality and microbiota changes, favoring the development of functional gastrointestinal disorders (FGIDs) - defined by dysregulation in the brain-gut interaction. Therefore, the present study investigated if Emotional-Single Prolonged Stress (E-SPS) induces depressive/anxiety-like phenotype and gut dysfunction in adult Swiss male mice. For this, mice of the E-SPS group were subjected to three stressors sequential exposure: immobilization, swimming, and odor of the predator for 7 days (incubation period). Next, animals performed behavior tests and 24 h later, samples of feces, blood, and colon tissue were collected. E-SPS increased the plasma corticosterone levels, immobility time in the tail suspension and forced swim test, decreased the grooming time in the splash test, OAT%, and OAE% in the elevated plus-maze test, as well as increased anxiety index. Mice of E-SPS had increased % of intestinal transit rate, % of fecal moisture content, and fecal pellets number, and decreased Claudin1 content in the colon. E-SPS decreased the relative abundance of Bacteroidetes phylum, Bacteroidia class, Bacteroidales order, Muribaculaceae and Porphyromonadaceae family, Muribaculum, and Duncaniella genus. However, E-SPS increased Firmicutes and Actinobacteria phylum, Coriobacteriales order, and the ratio of Firmicutes/Bacteroidetes, and demonstrated Mucispirillum genus presence. The present study showed that E-SPS induced depressive/anxiety-like phenotype, predominant diarrhea gut dysfunction, and modulated the gut bacterial microbiota profile in male adult Swiss mice. E-SPS might be a promising model for future studies on the brain-gut interaction and the development of FGIDs with psychological comorbidities.

Poo Matters! A scoping review of impact of constipation on epilepsy

BACKGROUND

Epilepsy is a common neurological disorder which frequently presents with co-morbid physical health conditions, including constipation. However, the nature of the relationship between the two conditions has not been well defined.

AIM

To quantify constipation's relationship with epilepsy and anti-seizure medication (ASM).

METHOD

A scoping review registered on PROSPERO (CRD42022320079) with suitable search terms was conducted and reported in accordance with PRISMA guidance. CINAHL, Embase, PsycInfo and MEDLINE electronic databases were searched by an information specialist. The Joanna Briggs Institute (JBI) critical appraisal tools alongside the Oxford Centre for Evidence Based Medicine (OCEBM) levels of evidence were used to assist in assessing relevance, quality, and results of the included publications.

RESULTS

Nine articles selected for inclusion in the review. The prevalence of irritable bowel syndrome (including constipation) was reported to be up to five times more frequent in people with epilepsy (PWE). Functional constipation was reported in 36% of PWE. Constipation was found to be the second most common co-morbid condition in children with epilepsy. Two studies found constipation to precede seizures. Constipation was reported as a common side effect of ASMs in PWE. Two studies rated OCEBM level 2 the remaining level 3.

CONCLUSION

Our findings suggest a higher prevalence of constipation in PWE. Co-occurring multimorbidity and resulting polypharmacy adds further complexity to the process of establishing aetiology of constipation in PWE. Potential contributory aetiological factors for constipation such as neurodevelopmental and genetic disorders, ASM side effects and the epilepsy itself require better understanding and research.

Regional and seasonal variations in functional abdominal pain and functional constipation prevalence among Saudi children

Objectives:

This study aimed to evaluate functional abdominal pain disorders and functional constipation prevalence in the central region of Saudi Arabia, and compare it to that of the western region.

Methods:

This was a cross-sectional study using online questionnaires targeting the general population of Riyadh region of Saudi Arabia. Subjects were randomly selected by sharing links on social media groups. Any parent with a 3–18-year-old child was included, and children with chronic medical illnesses or symptoms of organic GI disorders were excluded.

Results:

Three hundred nineteen subjects were included in the final analysis; the prevalence of functional abdominal pain disorders overall was 6.2% and the prevalence of functional constipation was 8.1%.

Conclusions:

Functional constipation diagnosis seems to be affected by life stressors or a previous viral illness. Seasonal variations had minimal effect on functional abdominal pain disorder and functional constipation symptom frequency and severity.

Incongruent Views of Functioning between Patients and Gastroenterologists: A Mixed Methods Study

Gastrointestinal patients, especially those diagnosed with functional digestive disorders (FGIDs), usually present a complex clinical picture that poses a challenge for their management in primary care. The main objective of the current research was to examine the relationship of the congruence of the perception of severity and quality of life between gastroenterologists and their patients with psychological distress and the helping attitude experienced by the latter attended in primary care centres. Additionally, we wanted to explore patients' and practitioners' perceptions. We performed a cross-sectional study with a total of 2261 patients (1562 analysed) that attended three primary care centres. Patients completed questionnaires that measured physical functioning, distress, and perception of helping attitude. Gastroenterologists registered the functional status of each participating patient. Patients were then invited to take part in the qualitative part of the study if they were considered to have incongruent views on their functioning with their gastroenterologist. In total, 52 patients took part in one of eight focus groups. Additionally, four individual interviews were carried out with three gastroenterologists and one consultation-liaison psychiatrist specialised in FGIDs. Both incongruence and functional diagnosis correlated with distress. However, incongruent views between patients and gastroenterologists explained more variance. Statistically significant differences in patients' helping attitude perception were detected between diagnostic but no incongruence groups. In the second stage of the study, a total of five themes were identified from the patient focus groups and the gastroenterologist interviews: illness-emotional and personal problems, disease-health system interaction, health system, intervention, and patients. The current research allowed us to confirm that incongruence in the perception of severity and quality of life between gastroenterologists and patients is related to psychological distress and that this occurs in a multifactorial context where the characteristics of the disorder interact with those of the health system.

Patterns of Functional Gastrointestinal Disorders Among Children in Makkah City: A Single Institutional Experience

Background Functional gastrointestinal disorders (FGIDs) are syndromes identified based on a group of symptoms defined according to the criteria of the Rome Foundation. The most commonly observed disorders among the pediatric population are functional abdominal pain disorders and functional constipation. This study aims to identify the patterns of FGIDs among children in Makkah, Saudi Arabia. Methods A retrospective cohort study was conducted at pediatric gastroenterology clinics from 2015 to 2019 in a tertiary centre in Makkah, Saudi Arabia. The FGID outcomes were compared with the patient's gender, age, and other characteristics using Statistical Package for the Social Sciences (SPSS, IBM Corp., Armonk, NY) software to analyze the data. Results One hundred and fifty-two participants met the inclusion criteria, with a mean age of 5.49 ± 3.27 and an average weight of 20.68 ± 12.15 kg. Male patients account for 59.2% of the total population. The prevalence of abdominal pain was 17.84%, while constipation was 50.93%. There was a statistically significant association between abdominal pain and independent variables such as family history (p=0.004) and age, particularly in older children (5-12 years; p=0.001). A statistically significant correlation was found between constipation with gender (p=0.032) and family history (p<0.001). Conclusion The prevalence of functional constipation and abdominal pain increased with age among children in Makkah City, with constipation being significantly more prevalent than functional abdominal pain. There is a significant relationship between age and family history with abdominal pain, whereas gender and family history are associated with a greater likelihood of constipation.

In silico investigation of molecular networks linking gastrointestinal diseases, malnutrition, and sarcopenia

Malnutrition (MN) is a common primary or secondary complication in gastrointestinal diseases. The patient’s nutritional status also influences muscle mass and function, which can be impaired up to the degree of sarcopenia. The molecular interactions in diseases leading to sarcopenia are complex and multifaceted, affecting muscle physiology, the intestine (nutrition), and the liver at different levels. Although extensive knowledge of individual molecular factors is available, their regulatory interplay is not yet fully understood. A comprehensive overall picture of pathological mechanisms and resulting phenotypes is lacking. In silico approaches that convert existing knowledge into computationally readable formats can help unravel mechanisms, underlying such complex molecular processes. From public literature, we manually compiled experimental evidence for molecular interactions involved in the development of sarcopenia into a knowledge base, referred to as the Sarcopenia Map. We integrated two diseases, namely liver cirrhosis (LC), and intestinal dysfunction, by considering their effects on nutrition and blood secretome. We demonstrate the performance of our model by successfully simulating the impact of changing dietary frequency, glycogen storage capacity, and disease severity on the carbohydrate and muscle systems. We present the Sarcopenia Map as a publicly available, open-source, and interactive online resource, that links gastrointestinal diseases, MN, and sarcopenia. The map provides tools that allow users to explore the information on the map and perform in silico simulations.

The duodenal mucosa associated microbiome, visceral sensory function, immune activation and psychological comorbidities in functional gastrointestinal disorders with and without self-reported non-celiac wheat sensitivity

Frequently, patients with functional gastrointestinal disorders (FGIDs) report intolerance of wheat products. We compared gastrointestinal symptoms, sensory function, psychiatric comorbidities, gut-homing immune cells, and duodenal mucosa-associated microbiome (d-MAM) in FGID patients and controls with and without self-reported wheat sensitivity (SR-NCWS). We recruited 40 FGID patients and 20 controls referred by GPs for treatment. Gastrointestinal/extraintestinal symptoms, visceral sensory function, psychological comorbidities, and SR-NCWS were assessed in a standardized approach. Peripheral gut homing T-cells (CD4⁺α4⁺β7⁺CCR9⁺/CD8⁺α4⁺β7⁺CCR9⁺) were quantified, and the d-MAM was assessed by DNA sequencing for 46 subjects. Factors of bacterial genera were extracted utilizing factor analysis with varimax rotation and factors univariately associated with FGID or SR-NCWS included in a subsequent multivariate analysis of variance to identify statistically independent discriminators. Anxiety scores (p < .05) and increased symptom responses to a nutrient challenge (p < .05) were univariately associated with FGID. Gut homing T-cells were increased in FGID patients with SR-NCWS compared to other groups (p all <0.05). MANOVA revealed that anxiety (p = .03), visceral sensory function (p = 0.007), and a d-MAM factor comprise members of the Alloprevotella, Prevotella, Peptostreptococcus, Leptotrichia, and Veillonella lineages were significantly (p = .001) associated with FGID, while gut homing CD4⁺α4⁺ β7⁺CCR9⁺ T-cells were associated (p = .002) with SR-NCWS. Compared to controls, patients with and without SR-NCWS show that there are shifts in the amplicon sequence variants within specific bacterial genera between the FGID subgroups (particularly Prevotella and Streptococcus) as well as distinct bacterial taxa discriminatory for the two different FGID subtypes. Compared to controls, both FGID patients with and without SR-NCWS have an increased symptom response to a standardized nutrient challenge and increased anxiety scores. The FGID patients with SR-NCWS - as compared to FGID without SR-NCWS (and controls without SR-NCWS) - have increased gut homing T-cells. The d-MAM profiles suggest species and strain-based variations between the two FGID subtypes and in comparison to controls.

Prevalence of gastrointestinal disorders in individuals with RASopathies: May RAS/MAP/ERK pathway dysfunctions be a model of neuropathic pain and visceral hypersensitivity?

RASopathies are a group of neurodevelopmental syndromes caused by germline variants in genes of the Ras/MAP/ERK pathway. Growth failure, neurological involvement, and pain represent the main features of these conditions. ERK signaling cascade plays a crucial role in nociception and visceral pain and it is likely implicated in the genesis of neuropathic pain and maintenance of altered pain states. We studied the prevalence of abdominal pain and functional gastrointestinal (GI) disorders in a large sample of individuals with RASopathies. A brief pain inventory questionnaire and semi-structured dedicated interview were used to investigate presence and localization of pain. A Rome IV questionnaire was used to screen for functional GI disorders. Eighty patients with clinical and molecular diagnoses of RASopathy were recruited (42 with Noonan syndrome; 17 with Costello Syndrome and 21 with cardio-facio-cutaneous syndrome). Overall, the prevalence of abdominal pain was 44% and prevalence of functional GI disorders was 78% with constipation, abdominal pain, and aerophagia being the most frequently detected ones. A significant association was found between pain and irritable bowel syndrome, functional constipation and aerophagia. Children with RASopathies have a high prevalence of functional gastrointestinal disorders. These children could represent a good in vivo model to study neuropathic pain, visceral hypersensitivity and gut-brain axis disorders.

Duodenal Eosinophils and Mast Cells in Functional Dyspepsia: A Systematic Review and Meta-Analysis of Case-Control Studies

BACKGROUND & AIMS

This study explored the link between duodenal eosinophils and mast cells in patients with functional dyspepsia (FD).

METHODS

MEDLINE (PubMed) and Embase electronic databases were searched until June 2021 for case-control studies reporting duodenal eosinophils and mast cells in FD. Pooled standardized mean difference (SMD), odds ratio, and 95% CIs of duodenal eosinophils and mast cells in FD patients and controls were calculated, using a random-effects model.

RESULTS

Twenty-two case-control studies with 1108 FD patients and 893 controls were identified. Duodenal eosinophils (SMD, 1.29; 95% CI, 0.85-1.73; P = .0001) and mast cells (SMD, 2.11; 95% CI, 1.14-3.07; P = .0001) were increased in FD patients compared with controls. Substantial heterogeneity was found (I² = 93.61, P = .0001; and I² = 96.69, P = .0001, respectively) and visual inspection of funnel plots confirmed publication bias. Degranulation of duodenal eosinophils was significantly higher in FD patients compared with controls (odds ratio, 3.78; 95% CI, 6.76-4.48; P = .0001), without statistically significant heterogeneity. We conducted a sensitivity analysis for duodenal eosinophils, by including only high-quality studies, and the results remained unchanged (SMD, 1.73; 95% CI, 1.06-2.40; P = .0001), with substantial heterogeneity. Postinfectious FD patients had increased duodenal eosinophils compared with controls (SMD, 3.91; 95% CI, 1.32-6.51; P = .001) and FD patients without any history of infection (SMD, 1.42; 95% CI, 0.88-1.96; P = .001). Helicobacter pylori-negative FD patients had significantly higher duodenal eosinophils compared with controls (SMD, 3.98; 95% CI, 2.13-5.84; P = .0001), with substantial heterogeneity. No significant difference in duodenal eosinophils was seen according to FD subtypes.

CONCLUSIONS

This meta-analysis suggests a link between duodenal microinflammation and FD. However, the quality of evidence is very low, largely owing to the unexplained heterogeneity and serious risk of publication bias in all comparative analyses. Thus, causality remains uncertain and further studies are required.

Alterations to the duodenal microbiota are linked to gastric emptying and symptoms in functional dyspepsia

OBJECTIVE

Functional dyspepsia (FD) is a complex disorder, with debilitating epigastric symptoms. Evidence suggests alterations in gastrointestinal (GI) motility, visceral hypersensitivity, permeability and low-level immune activation in the duodenum may play a role. However, we still have a relatively poor understanding of how these factors interact to precipitate the onset of FD symptoms which are frequently meal related. The duodenal microbiota, in combination with specific dietary substrates, may be important mediators in disease pathophysiology; however, these interlinked factors have not been thoroughly investigated in FD.

DESIGN

Eighty-six individuals (56 FD, 30 controls) undergoing endoscopy were consecutively recruited and underwent detailed clinical assessment, including upper GI symptoms, gastric emptying and dietary assessment. Duodenal biopsies were obtained aseptically, and the mucosa-associated microbiota (MAM) analysed via 16S rRNA gene amplicon sequencing.

RESULTS

The relative abundances of predominant members of the Firmicutes, Bacteroidota and Fusobacteriota phyla were linked to symptom burden in FD. Inverse relationships between the relative abundances of Streptococcus and Prevotella, and the relative abundance of Veillonella spp with gastric emptying time, were also observed. No significant differences in long-term nutrient intake or diet quality were found between FD and controls, and there appeared to be limited association between habitual diet and duodenal MAM profiles.

CONCLUSION

This study suggests a link between the duodenal MAM, gastric emptying and FD symptoms, and this is largely independent of long-term dietary intake.

Aspalathus linearis (Rooibos) and Agmatine May Act Synergistically to Beneficially Modulate Intestinal Tight Junction Integrity and Inflammatory Profile

In order to promote gastrointestinal health, significant increases in the prevalence of gastrointestinal disorders should be paralleled by similar surges in therapeutics research. Nutraceutical interventions may play a significant role in patient management. The current study aimed to determine the potential of Aspalathus linearis (rooibos) to prevent gastrointestinal dysregulation resulting from high-dose trace-amine (TA) exposure. Considering the substantial female bias in functional gastrointestinal disorders, and the suggested phytoestrogenicity of rooibos, the study design allowed for a comparison between the effects of an ethanol extract of green rooibos and 17β-estradiol (E2). High levels of ρ-tyramine (TYR) and agmatine (AGM), but not β-phenethylamine (PEA) or tryptamine (TRP), resulted in prostaglandin E2 (PGE2) hypersecretion, increased tight-junction protein (TJP; occludin and ZO-1) secretion and (dissimilarly) disrupted the TJP cellular distribution profile. Modulating benefits of rooibos and E2 were TA-specific. Rooibos pre-treatment generally reduced IL-8 secretion across all TA conditions and prevented PGE2 hypersecretion after exposure to both TYR and AGM, but was only able to normalise TJP levels and the distribution profile in AGM-exposed cells. In contrast, E2 pre-treatment prevented only TYR-associated PGE2 hypersecretion and TJP dysregulation. Together, the data suggest that the antioxidant and anti-inflammatory effects of rooibos, rather than phytoestrogenicity, affect benefits illustrated for rooibos.

Association of Diet, Body Mass Index, and Lifestyle on the Gastrointestinal Health Risk in a Sample of Adults

Gastrointestinal functional disorders are characterized by abnormalities in motility with visceral hypersensitivity, representing a global public health problem. We aimed to determine whether eating habits, lifestyle characteristics, and body mass index (BMI) are associated with gastrointestinal health risk. The Gastrointestinal Health (GIH) test of the World Gastroenterology Organization (WGO) and the Roma IV criteria were applied. We obtained information on food consumption habits and aerobic exercise, among other variables. Not exercising regularly, drinking water and eating vegetables less than recommended, having high body weight, and taking symptomatic medication were variables that explained 73% of the probabilities of not having good GIH (R² = 0.734). According to Rome IV criteria, women had a 50% higher risk than men of having functional bowel disorder (RR 1.6, 95% CI: 1.04, 2.45). Among the men studied, eating few or no vegetables and drinking less than 1 L of water daily was more frequent; however, the women had significantly more intestinal symptoms. In addition, constipation was higher among women than men (p = 0.020). All of the above explains the prognostic value of eating habits and the importance of paying attention to body weight to reduce the risk of gastrointestinal disease.

Abdominal massage: A review of clinical and experimental studies from 1990 to 2021

OBJECTIVE

To systematically review the current state and holistic application of abdominal massage (AM).

DESIGN

A systematic review of qualitative evidence was conducted. All English articles exploring the topic of AM that had been published until the end of June 2021 were retrieved.

DATA SOURCES

The PubMed, Cochrane library, and Embase databases were accessed. Some original texts were obtained from Google Scholar.

DATA EXTRACTION AND SYNTHESIS

Two authors independently evaluated all search data to identify relevant studies. Disagreements were settled by discussion with a third author. Results were independently extracted into standardized sheets and checked for accuracy.

MAIN RESULTS

A total of 107 full-text reports were eligible for inclusion. Adult digestive disorders, pediatric disorders, gynecological disorders, obstetric disorders, metabolic disorders, psychological disorders, the side effects of AM, and animal experiments accounted for 49.53%, 14.02%, 7.48%, 7.48%, 4.67%, 4.67%, 5.61%, and 6.54% of all these papers, respectively, with most reports focusing on clinical studies.

CONCLUSION

The variety of diseases treated with AM is gradually increasing, and the treatment programs of AM for many diseases are being gradually optimized. Different forms of AM, especially mechanical AM, have been widely studied; the side effects of AM have also been considered; and the possible mechanisms of AM therapy continue to be discovered. In general, AM is an effective and safe therapy and can be widely used in various diseases, but further studies are necessary to clarify the mechanism of AM for different diseases. In the future, AM could become an even safer, more popular, and more modern therapy.

Epidemiology of functional gastrointestinal disorders using ROME III adult questionnaire, a population based cross sectional study in Karachi-Pakistan

Objective

Functional Gastrointestinal Disorder (FGIDs) are a heterogenous group of disorders, with Irritable Bowel Syndrome (IBS) and Functional Dyspepsia (FD) being the most common disorders worldwide. The purpose of this study was to identify the spectra of FGIDs classified according to the ROME III criteria amongst an adult Pakistani population. It also aimed to correlate the psychosocial alarm symptoms with the prevalence of FGIDs and report the overlap of all FGID.

Design

This was a community based cross-sectional study. Multi-stage cluster sampling technique was applied, and 1062 households were initially randomly chosen using systematic sampling technique. Only one person from each household was enrolled in the study. After eligibility screening, 860 participating individuals were requested to fill out a structured ROME III interview questionnaire, administered to them by a trained interviewer.

Results

FGIDs were diagnosed in 468 individuals (54.4%), out of 860 participants. FD was found to be the most prevalent (70.2%), followed by Functional Heartburn (58.9%) and Functional bloating (56.6%). Amongst a total of 468 participants diagnosed with FGIDs, 347 (74.1%) had overlapping disorders. There was also a higher incidence of psychosocial alarm symptoms including higher pain severity (62.6% vs 46.4%) and being victimized at some point in their lives (26.1% vs 6.6%) amongst FGID patients.

Conclusion

There is a high disease burden of FGIDs in this study population, with approximately half of the population suffering from at least one type of FGID. Overlapping disorders are also common in this part of the world.

Concomitant Irritable Bowel Syndrome Does Not Influence the Response to Antimicrobial Therapy in Patients with Functional Dyspepsia

BACKGROUND AND AIMS

Antimicrobial therapy improves symptoms in patients with irritable bowel syndrome (IBS), but the efficacy in functional dyspepsia (FD) is largely unknown. While FD and IBS frequently overlap, it is unknown if concomitant IBS in FD alters the response to antimicrobial therapy in FD. Thus, we aimed to assess and compare the effect of antimicrobial therapy on visceral sensory function and symptom improvement in FD patients with and without IBS.

METHODS

Adult patients with FD with or without IBS received rifaximin 550 mg BD for 10 days, followed by a 6-week follow-up period. The total gastrointestinal symptom score as measured by the SAGIS (Structured Assessment of Gastrointestinal Symptoms) questionnaire and subscores (dyspepsia, diarrhea, and constipation), symptom response to a standardized nutrient challenge and normalization of the glucose breath tests were measured.

RESULTS

Twenty-one consecutive adult patients with FD and 14/21 with concomitant IBS were recruited. Treatment with rifaximin resulted in a significant (p = 0.017) improvement in the total SAGIS score from 34.7 (± 15.4) at baseline to 26.0 (± 16.8) at 2 weeks and 25.6 (± 17.8) at 6 weeks post-treatment. Similarly, compared to baseline there was a statistically significant improvement in SAGIS subscores for dyspepsia and diarrhea (all p < 0.05) and effects persisted for 6 weeks post-treatment. Similarly, the symptom score (and subscores) following a standardized nutrient challenge improved significantly (p < 0.001) 2 weeks post-treatment. The presence of concomitant IBS did not significantly influence the improvement of symptoms after antibiotic therapy (all p > 0.5).

CONCLUSIONS

In FD patients, the response to antimicrobial therapy with rifaximin is not influenced by concomitant IBS symptoms.

Current and Future Approaches for Diagnosing Small Intestinal Dysbiosis in Patients With Symptoms of Functional Dyspepsia

The development and application of next generation sequencing technologies for clinical gastroenterology research has provided evidence that microbial dysbiosis is of relevance for the pathogenesis of gastrointestinal and extra-intestinal diseases. Microbial dysbiosis is characterized as alterations of diversity, function, and density of the intestinal microbes. Emerging evidence suggests that alterations of the gastrointestinal microbiome are important for the pathophysiology of a variety of functional gastrointestinal conditions, e.g., irritable bowel syndrome (IBS) and functional dyspepsia (FD), also known as disorders of brain-gut axis interaction. Clinicians have for many years recognized that small intestinal bacterial overgrowth (SIBO) is typified by a microbial dysbiosis that is underpinned by abnormal bacterial loads in these sites. SIBO presents with symptoms which overlap with symptoms of FD and IBS, point toward the possibility that SIBO is either the cause or the consequence of functional gastrointestinal disorders (FGIDs). More recently, new terms including “intestinal methanogen overgrowth” and “small intestinal fungal overgrowth” have been introduced to emphasize the contribution of methane production by archea and fungi in small intestinal dysbiosis. There is emerging data that targeted antimicrobial treatment of SIBO in patients with FD who simultaneously may or may not have IBS, results in symptom improvement and normalization of positive breath tests. However, the association between SIBO and FGIDs remains controversial, since widely accepted diagnostic tests for SIBO are lacking. Culture of jejunal fluid aspirate has been proposed as the “traditional gold standard” for establishing the diagnosis of SIBO. Utilizing jejunal fluid culture, the results can potentially be affected by cross contamination from oropharyngeal and luminal microbes, and there is controversy regarding the best cut off values for SIBO diagnosis. Thus, it is rarely used in routine clinical settings. These limitations have led to the development of breath tests, which when compared with the “traditional gold standard,” have sub-optimal sensitivity and specificity for SIBO diagnosis. With newer diagnostic approaches–based upon applications of the molecular techniques there is an opportunity to characterize the duodenal and colonic mucosa associated microbiome and associated gut microbiota dysbiosis in patients with various gastrointestinal and extraintestinal diseases. Furthermore, the role of confounders like psychological co-morbidities, medications, dietary practices, and environmental factors on the gastrointestinal microbiome in health and disease also needs to be explored.

The difference of disrupted rhythms of life, work and entertainment between patients with FGIDs and healthy people and their associations with psychological disorders under COVID-19 pandemic

AIMS

To investigate the differences in disrupted rhythms between healthy people and patients with functional gastrointestinal disorders (FGIDs) and their associations with mood disorders during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

The rhythm scales were composed of subscales 1 and 2 for the assessment of life-work and entertainment rhythms, respectively; Zung's Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) were used to assess mood disorders.

RESULTS

A total of 671 patients with FGIDs and 4373 healthy people successfully participated. The scores of subscales 1 and 2 for patients with FGIDs were significantly higher than those for healthy people (p < .005). The SAS and SDS scores, their prevalence rates were significantly higher than those for the healthy group (all p < .001). Health status, current occupation, life-work rhythm, SDS, and SAS were independent related factors of FGIDs. The score of life-work-entertainment rhythm was significantly positively correlated with SDS and SAS (both p < .001).

CONCLUSION

Disrupted rhythms in patients with FGIDs under the COVID-19 pandemic were more frequently and significantly positively associated with mood disorders.

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.

Tissue engineering of the gastrointestinal tract: the historic path to translation

The gastrointestinal (GI) tract is imperative for multiple functions including digestion, nutrient absorption, and timely waste disposal. The central feature of the gut is peristalsis, intestinal motility, which facilitates all of its functions. Disruptions in GI motility lead to sub-optimal GI function, resulting in a lower quality of life in many functional GI disorders. Over the last two decades, tissue engineering research directed towards the intestine has progressed rapidly due to advances in cell and stem-cell biology, integrative physiology, bioengineering and biomaterials. Newer biomedical tools (including optical tools, machine learning, and nuanced regenerative engineering approaches) have expanded our understanding of the complex cellular communication within the GI tract that lead to its orchestrated physiological function. Bioengineering therefore can be utilized towards several translational aspects: (i) regenerative medicine to remedy/restore GI physiological function; (ii) in vitro model building to mimic the complex physiology for drug and pharmacology testing; (iii) tool development to continue to unravel multi-cell communication networks to integrate cell and organ-level physiology. Despite the significant strides made historically in GI tissue engineering, fundamental challenges remain including the quest for identifying autologous human cell sources, enhanced scaffolding biomaterials to increase biocompatibility while matching viscoelastic properties of the underlying tissue, and overall biomanufacturing. This review provides historic perspectives for how bioengineering has advanced over time, highlights newer advances in bioengineering strategies, and provides a realistic perspective on the path to translation.

Re-evaluation of the Cardiovascular Safety Profile of Tegaserod: A Review of the Clinical Data

BACKGROUND AND AIMS

Tegaserod is a 5-HT₄ receptor agonist approved for irritable bowel syndrome with constipation in women <65 years of age without a history of cardiovascular ischemic events. Safety data are presented from 2 external adjudications from the 2018 Gastrointestinal Drugs Advisory Committee meeting supporting tegaserod's reintroduction after its voluntary 2007 withdrawal. Withdrawal was based on an internal adjudication using pooled placebo-controlled tegaserod data to identify potential cardiovascular ischemic signals.

METHODS

An independent committee conducted an external adjudication to evaluate 24 possible cardiovascular ischemic events (tegaserod: n = 20; placebo: n = 4) identified internally. A second independent external adjudication further evaluated these events.

RESULTS

A total of 18,645 patients were included (tegaserod: n = 11,614; placebo: n = 7031). The first adjudication identified 14 (0.075%) events (tegaserod: n = 13 [0.11%]; placebo: n = 1 [0.014%]). All patients had ≥1 cardiovascular risk factor, and 11 had ≥2. The second adjudication identified 390 events, 24 (0.13%) were classified as probable new or worsening events (tegaserod: 18 [0.16%]; placebo: 6 [0.09%]). For tegaserod, 7 (0.06%) were coronary or cerebrovascular ischemic events compared with 1 (0.01%) for placebo (odds ratio, 4.24; 95% confidence interval, 0.52-34.74; P = .273). All tegaserod patients reporting cardiovascular events had ≥1 risk, including cardiovascular disease, hyperlipidemia, ≥55 years of age, hypertension, diabetes, obesity, and smoking. Women <65 years of age without a history of cardiovascular ischemic events and ≤1 cardiovascular risk factor receiving tegaserod experienced no major adverse cardiovascular event(s).

CONCLUSIONS

Two independent, external adjudications suggest that tegaserod is safe for women <65 years of age with irritable bowel syndrome with constipation, no history of cardiovascular ischemic events, and ≤1 cardiovascular risk factor.

Role-Playing Between Environmental Pollutants and Human Gut Microbiota: A Complex Bidirectional Interaction

There is a growing interest in the characterization of the involvement of toxicant and pollutant exposures in the development and the progression of several diseases such as obesity, diabetes, cancer, as well as in the disruption of the immune and reproductive homeostasis. The gut microbiota is considered a pivotal player against the toxic properties of chemicals with the establishment of a dynamic bidirectional relationship, underlining the toxicological significance of this mutual interplay. In fact, several environmental chemicals have been demonstrated to affect the composition, the biodiversity of the intestinal microbiota together with the underlining modulated metabolic pathways, which may play an important role in tailoring the microbiotype of an individual. In this review, we aimed to discuss the latest updates concerning the environmental chemicals–microbiota dual interaction, toward the identification of a distinctiveness of the gut microbial community, which, in turn, may allow to adopt personalized preventive strategies to improve risk assessment for more susceptible workers.

Probiotics and Phytochemicals: Role on Gut Microbiota and Efficacy on Irritable Bowel Syndrome, Functional Dyspepsia, and Functional Constipation

Functional gastrointestinal disorders (FGIDs), such as irritable bowel syndrome, functional constipation, and functional dyspepsia, have had a high prevalence over the past few years. Recent evidence suggests that functional foods and bioactive compounds, such as probiotics and phytochemicals, may have a positive effect in treating the symptoms of the above diseases. In this systematic review study, 32 published studies were selected with the use of comprehensive scientific databases, according to PRISMA guidelines, with emphasis on recent interventional studies that reflect the effect of probiotics and selected phytochemicals on the improvement of FGID symptoms. The bioactive compounds in the selected studies were administered to patients either in capsule form or in enriched food products (yogurt, juice, etc.). According to the results, there is a correlation between the consumption of probiotics and phytochemicals, such as polyphenols, and the relief of symptoms in selected gastrointestinal disorders. Enriching foods that are regularly consumed by the population, such as fruit juices, yogurt, and cheese, with ingredients that may have a positive effect on gastrointestinal disorders, could be a possible novel goal for the management of these diseases. However, further evidence is required for the role of probiotics and phytochemicals in FGIDs to be fully understood.

FUNCTIONAL ABDOMINAL PAIN IS THE MAIN ETIOLOGY AMONG CHILDREN REFERRED TO TERTIARY CARE LEVEL FOR CHRONIC ABDOMINAL PAIN

ABSTRACT Background Chronic abdominal pain (CAP) carries a significant burden of disease. The last edition of the Rome Criteria (Rome IV) allows the diagnosis of functional gastrointestinal disorders (FGIDs) according to symptoms-based criteria; however, patients continue to experience a delay in their diagnosis and to be submitted to different interventions before the establishment of a positive diagnosis. Objective We aimed to characterize etiology, clinical features, and interventions in a pediatric cohort of patients with CAP secondary to FGIDs, who were referred to our tertiary care university-affiliated hospital, in Brazil. Methods A retrospective descriptive study of children and adolescents (aged 20 years and younger) referred to our institution, from January/2013 to December/2018, for CAP, and who fulfilled criteria for FGIDs classified according to Rome IV criteria. Results Three hundred twenty-eight patients with CAP were screened, of which 67.9% (223 patients) fulfilled the criteria for FGIDs and were included in the study. Sixty percent were female, with a mean age of 8.3 years. At the time of referral, the mean duration of symptoms was 2.8 years. Length/height for age and weight for age mean z-scores were -0.08±1.87 and -0.38±1.62, respectively. Functional abdominal pain not otherwise specified was overall the most common diagnosis (70.4%). Before establishing the diagnosis of FGIDs, multiple pharmacological interventions were described, while after, the mainstay of therapy was education/reassurance and dietary interventions. Thirty-two percent of patients did not further require specialized follow-up. Conclusion Even at the tertiary care level, FGIDs were still the most common etiology of chronic abdominal pain, particularly functional abdominal pain not otherwise specified. Despite the relatively long duration of symptoms at referral, cessation of specialized care follow-up was possible in approximately a third of the cases.

Impact of Helicobacter pylori infection on fluid duodenal microbial community structure and microbial metabolic pathways

Background

The bioactivities of commensal duodenal microbiota greatly influence the biofunction of hosts. We investigated the role of Helicobacter pylori infection in extra-gastroduodenal diseases by determining the impact of H. pylori infection on the duodenal microbiota. We sequenced 16 S rRNA genes in samples aspirated from the descending duodenum of 47 (male, 20; female, 27) individuals who were screened for gastric cancer. Samples were analysed using 16 S rRNA gene amplicon sequencing, and the LEFSe and Kyoto Encyclopaedia of Genes and Genomes methods were used to determine whether the duodenal microflora and microbial biofunctions were affected using H. pylori infection.

Results

Thirteen and 34 participants tested positive and negative for H. pylori, respectively. We identified 1,404 bacterial operational taxonomic units from 23 phyla and 253 genera. H. pylori infection changed the relative mean abundance of three phyla (Proteobacteria, Actinobacteria, and TM7) and ten genera (Neisseria, Rothia, TM7-3, Leptotrichia, Lachnospiraceae, Megasphaera, F16, Moryella, Filifactor, and Paludibacter). Microbiota features were significantly influenced in H. pylori-positive participants by 12 taxa mostly classified as Gammaproteobacteria. Microbial functional annotation revealed that H. pylori significantly affected 12 microbial metabolic pathways.

Conclusions

H. pylori disrupted normal bacterial communities in the duodenum and changed the biofunctions of commensal microbiota primarily by upregulating specific metabolic pathways. Such upregulation may be involved in the onset of diseases associated with H. pylori infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02437-w.

The Effect of Electroacupuncture Treatment with Different Intensities for Functional Diarrhea: A Randomized Controlled Trial

Background

Electroacupuncture (EA) may have a role in the treatment of diarrhea symptoms. However, the efficacy and safety of EA with different current intensities in improving gastrointestinal function, psychology, and quality of life (QOL) of functional diarrhea (FD) remain unknown.

Objective

To investigate the efficacy and safety of EA with different current intensities in improving gastrointestinal function, psychology, and QOL for FD patients.

Methods

73 FD patients were randomly divided into three groups: low current intensity group (LI) of EA, high current intensity group (HI) of EA, and loperamide control group (LC). Four weeks of treatment were provided in the three groups. The primary outcome was the proportion of normal defecation. Additional outcomes included the change from baseline for the weekly spontaneous bowel movements (SBMs) and the change from baseline for the mean Bristol Stool Form Scale (BSFS). QOL was assessed by the 36-item short-form health survey (SF-36). Self-rating Anxiety Scale (SAS) and Self-rating Depression Scale (SDS) were used to assess the psychology state.

Results

Low current intensity of EA significantly improved the proportion of normal defecation during treatment and follow-up period (P < 0.01). EA significantly improves the mean BSFS scores and weekly SBMs, and this efficacy is equivalent to loperamide (P < 0.05). The SF-36 scores of general health in LI and HI groups and vitality and mental health in LI group were significantly increased compared to baseline (P < 0.05). Low current intensity of EA can significantly improve SAS and SDS scores (P < 0.05).

Conclusions

EA significantly improved stool consistency and weekly SBMs in FD patients. Compared with loperamide, low current intensity of EA may have a better sustainable effect in restoring normal defecation in patients with FD, and it can also effectively improve QOL, anxiety, and depression. However, larger sample sizes are needed to determine safety and efficacy. Trial registration number: NCT01274793.

[Irritable bowel syndrome and functional dyspepsia : Diagnosis and treatment]

Irritable bowel syndrome (IBS) and functional dyspepsia are chronic diseases of the digestive tract that challenge both patients and physicians due to their difficult diagnosis and limited treatment options. The international Rome IV diagnostic criteria are commonly used for research purposes. For IBS, the diagnostic criteria based on the German S3 guideline offer a less complicated alternative for everyday clinical practice. A thorough history and basic diagnostic work-up are essential for diagnosis, as reliable biomarkers are still lacking. Clinical manifestations of both disorders are variable, and it has been useful to allocate subtypes based on leading symptom clusters; these may facilitate the choice of diagnostic tests as well as symptomatic treatment approaches. Used correctly, the combination of available drug (mostly off-label) and non-drug options can help to reduce symptoms and improve quality of life.

Effects of Alkaline-Reduced Water on Gastrointestinal Diseases

Living a healthy lifestyle is the most important need in the world today. However, oxidative stress (OS) is caused by several stress-inducing factors such as smoking, alcohol consumption, chronic diseases, and inflammatory responses, oxygen-free radicals are produced in excess and can damage major organs in the body. This phenomenon has been implicated in the pathogenesis of several gastrointestinal (GI) diseases, including gastritis, constipation, and inflammatory bowel diseases, which include Crohn’s disease, ulcerative colitis, functional dyspepsia, acid reflux, diverticular disease, and irritable bowel syndrome. In this review article, we provide a brief overview of the role of OS in the pathogenesis of GI disorders. Additionally, we discuss the therapeutic role of alkaline-reduced water (ARW) on GI diseases and existing studies on ARW related to GI diseases. Furthermore, we believe that findings from this review article will enhance the knowledge of the readers on the role of ARW on OS and inflammation-based GI diseases.

Functional gastrointestinal disorders. Overlap syndrome Clinical guidelines of the Russian Scientific Medical Society of Internal Medicine and Gastroenterological Scientific Society of Russia

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