New insights into irritable bowel syndrome: from pathophysiology to treatment

Aberrant functional connectivity patterns in the pregenual anterior cingulate cortex and anterior midcingulate cortex of patients with irritable bowel syndrome accompanied by depressive symptoms

Irritable bowel syndrome (IBS) is a common brain-gut disorder often accompanied by depressive symptoms, with atrophy and hyperactivity of the anterior cingulate gyrus (ACC) being key drivers of both IBS and its psychiatric comorbidities. This study aimed to investigate the functional connectivity (FC) patterns of pregenual ACC (pgACC) and anterior midcingulate cortex (aMCC) in IBS patients with depressive symptoms (DEP-IBS). A whole-brain FC analysis was conducted using pgACC and aMCC as regions of interest in three groups: 28 DEP-IBS patients, 21 IBS patients without depressive symptoms (nDEP-IBS), and 36 matched healthy controls (HCs). Partial correlation and mediation analyses were performed between abnormal FC and clinical symptoms. The ability of aberrant FC to identify IBS and its psychiatric comorbidity was evaluated using receiver operating characteristic (ROC) curve. DEP-IBS patients exhibited increased pgACC-related FC in the left medial prefrontal cortex (mPFC) and aMCC-related FC in the right middle frontal gyrus, angular gyrus and cerebellum, while showing decreased aMCC-related FC in the right precentral gyrus, superior parietal gyrus and precuneus. Both patient groups demonstrated increased FC between aMCC and left dorsolateral prefrontal cortex (dlPFC), effectively distinguishing them from HCs (AUC = 0.755). The FC between pgACC and left mPFC partially mediated the relationship between gastrointestinal and depressive symptoms, effectively distinguishing DEP-IBS from nDEP-IBS patients (AUC = 0.808). Aberrant FC within the emotional arousal network may serve as a neurobiological marker for IBS with comorbid depression. Furthermore, abnormal FC between the aMCC and the dlPFC may underlie the neural mechanism of IBS.

Tea-derived exosome-like nanoparticles prevent irritable bowel syndrome induced by water avoidance stress in rat model

BACKGROUND AND AIM

Exosome-like nanoparticles (ELNs) have emerged as crucial mediators of intercellular communication, evaluated as potential bioactive nutraceutical biomolecules. We hypothesized that oral ELNs have some therapeutic effect on irritable bowel syndrome (IBS).

METHODS

In our study, ELNs from tea (Camellia sinensis) leaves were extracted by differential centrifugation. We investigated the role of ELNs by assessing visceral hypersensitivity, body weight, bowel habits, tight junctions, and corticotropin-releasing hormone (CRH) in rats subjected to water avoidance stress (WAS) to mimic IBS with and without ELNs (1 mg/kg per day) for 10 days.

RESULTS

The average diameter of ELNs from LCC, FD and MZ tea tree were 165 ± 107, 168 ± 94, and 168 ± 108 nm, the concentration of ELNs were 1.2 × 1013, 1 × 1013, and 1.5 × 1013 particles/mL, respectively. ELNs can be taken up by intestinal epithelial cells. In WAS rats, ELNs significantly restored weight, recovered tight junctions, decreased CRH, and CRH receptor 1 expression levels and inhibited abdominal hypersensitivity in comparison to positive control.

CONCLUSIONS

Oral tea-derived ELN improves symptoms of IBS by potentially modulating the CRH pathway.

Functional Abdominal Bloating and Gut Microbiota: An Update

(1) Background: Functional abdominal bloating and distension (FAB/FAD) are common disorders of the gut-brain interaction. Their physiopathology is complex and not completely clarified, although gut microbiota imbalances play a central role. The treatment of FAB/FAD still represents a clinical challenge for both patients and healthcare providers. Gut microbiota modulation strategies might play a crucial role in their management. The aim of this narrative review was to update the current evidence on FAB/FAD, with a focus on gut microbiota. (2) Methods: In October 2023, a review was conducted through the Medline, PubMed, and Embase databases. Selected literature included all available English-edited studies (randomized controlled trials and cross-sectional, cohort, and case-control studies). (3) Results: Twelve studies were selected, most of which investigated the relationship between IBS and microbiota, with bloating being one of its symptoms. The studies suggest that restoring a balanced microbiome appears to be the most promising solution for better management of FAB/FAD. Targeted approaches, such as the use of probiotics, prebiotics, antibiotics such as rifaximin or dietary modifications, may hold the key to alleviating symptoms. Other therapeutic options, such as diet, neuromodulators, and brain-gut behavioral therapies (i.e., cognitive-behavioral therapy) have shown promising outcomes, but strong data are still lacking. (4) Conclusions: Targeted approaches that focus on the gut microbiota, such as the use of probiotics, prebiotics, and antibiotics, are essential in managing FAB/FAD. Understanding the complex relationship between gut microbiota and FAB/FAD is crucial for developing effective treatments. Further studies are needed to explore the specific roles of different microbial populations in patients with FAB/FAD to enhance therapeutic strategies.

Rapid biotransformation of STW 5 constituents by human gut microbiome from IBS- and non-IBS donors

STW 5, a blend of nine medicinal plant extracts, exhibits promising efficacy in treating functional gastrointestinal disorders, notably irritable bowel syndrome (IBS). Nonetheless, its effects on the gastrointestinal microbiome and the role of microbiota on the conversion of its constituents are still largely unexplored. This study employed an experimental ex vivo model to investigate STW 5's differential effects on fecal microbial communities and metabolite production in samples from individuals with and without IBS. Using 560 fecal microcosms (IBS patients, n = 6; healthy controls, n = 10), we evaluated the influence of pre-digested STW 5 and controls on microbial and metabolite composition at time points 0, 0.5, 4, and 24 h. Our findings demonstrate the potential of this ex vivo platform to analyze herbal medicine turnover within 4 h with minimal microbiome shifts due to abiotic factors. While only minor taxonomic disparities were noted between IBS- and non-IBS samples and upon treatment with STW 5, rapid metabolic turnover of STW 5 components into specific degradation products, such as 18β-glycyrrhetinic acid, davidigenin, herniarin, 3-(3-hydroxyphenyl)propanoic acid, and 3-(2-hydroxy-4-methoxyphenyl)propanoic acid occurred. For davidigenin, 3-(3-hydroxyphenyl)propanoic acid and 18β-glycyrrhetinic acid, anti-inflammatory, cytoprotective, or spasmolytic activities have been previously described. Notably, the microbiome-driven metabolic transformation did not induce a global microbiome shift, and the detected metabolites were minimally linked to specific taxa. Observed biotransformations were independent of IBS diagnosis, suggesting potential benefits for IBS patients from biotransformation products of STW 5.

IMPORTANCE

STW 5 is an herbal medicinal product with proven clinical efficacy in the treatment of functional gastrointestinal disorders, like functional dyspepsia and irritable bowel syndrome (IBS). The effects of STW 5 on fecal microbial communities and metabolite production effects have been studied in an experimental model with fecal samples from individuals with and without IBS. While only minor taxonomic disparities were noted between IBS- and non-IBS samples and upon treatment with STW 5, rapid metabolic turnover of STW 5 components into specific degradation products with reported anti-inflammatory, cytoprotective, or spasmolytic activities was observed, which may be relevant for the pharmacological activity of STW 5.

Effect of Pilates exercises on symptoms of irritable bowel syndrome in women: a randomized controlled trial

Objective

The treatment of irritable bowel syndrome (IBS) is challenging, calling for therapeutic strategies other than pharmacological treatment. Therefore, this study aimed to investigate the effects of Pilates exercises on IBS symptoms and severity, frequency of complete spontaneous bowel movements, fatigue, anxiety, depression, and body weight in women with IBS.

Methods

Sixty women with IBS, aged 20-45, completed this study. They were randomly assigned to two equal groups: a study group (n = 30) and a control group (n = 30). The study group received an 8-week Pilates exercise program (2 sessions per week) in addition to dietary advice, while the control group received dietary advice only. Inclusion criteria were women, IBS diagnosed based on Rome IV Diagnostic criteria, constipation-predominant IBS, and moderate to severe IBS. The outcome measures were the IBS severity scoring system (IBS-SSS), the frequency of complete spontaneous bowel movements, the modified fatigue impact scale (MFIS), hospital anxiety and depression (HADS) scale, and body weight (BW).

Results

The study group showed more significant improvements than the control group in total IBS-SSS score (Cohen d = 0.73, p < 0.001), frequency of complete spontaneous bowel movements (Cohen d = 0.50, p < 0.001), total MFIS score (Cohen d = 0.74, p < 0.001), anxiety (Cohen d = 0.56, p < 0.001), and depression (Cohen d = 0.64, p < 0.001). The study group also showed a significant reduction in body weight compared to baseline (p < 0.05). The control group showed significant improvements in all outcomes, except body weight, compared to baseline (p < 0.05).

Conclusion

Pilates exercises, used in addition to dietary advice, may significantly improve IBS symptoms and severity, frequency of complete spontaneous bowel movements, and alleviate fatigue, anxiety, and depression moderately more than dietary advice alone in women with constipation-predominant IBS. Nevertheless, dietary advice alone may also significantly improve these outcomes in this cohort.

Therapeutic effects of curcumin on constipation-predominant irritable bowel syndrome is associated with modulating gut microbiota and neurotransmitters

Introduction

Constipation-predominant irritable bowel syndrome (IBS-C) is a functional bowel disease that affects 10-20% of the population worldwide. Curcumin (CUR) is widely used in traditional Chinese medicine to treat IBS, but its mechanism of action needs further investigation.

Methods

In this study, we used mosapride (MOS) as a positive control to evaluate the changes in gut microbiota in IBS-C rat models after treatment with CUR or MOS by analyzing 16S rDNA variation. In addition, we used enzyme immunoassay kits and immunohistochemical analysis to investigate whether CUR or MOS influenced serotonin (5-HT), substance P (SP), and vasoactive intestinal peptide (VIP) levels in the serum and colon of IBS-C rats.

Results

The study showed that rats supplemented with CUR showed significantly increased fecal weight, fecal water content, small intestine transit rate and significantly decreased serum levels of 5-HT, VIP and SP compared to the IBS group (p < 0.05). In addition, treatment with CUR changed the relative abundance of Blautia, Sutterella, Acetanaerobacterium and Ruminococcus2 in the gut microbiota.

Discussion

This study showed that the efficacy of CUR on IBS-C was possibly by modulating the microbiota and lowering the serum levels of HT, SP, and VIP.

The critical role of gut-brain axis microbiome in mental disorders

The Gut-brain axis is a bidirectional neural and humoral signaling that plays an important role in mental disorders and intestinal health and connects them as well. Over the past decades, the gut microbiota has been explored as an important part of the gastrointestinal tract that plays a crucial role in the regulation of most functions of various human organs. The evidence shows several mediators such as short-chain fatty acids, peptides, and neurotransmitters that are produced by the gut may affect the brain's function directly or indirectly. Thus, dysregulation in this microbiome community can give rise to several diseases such as Parkinson's disease, depression, irritable bowel syndrome, and Alzheimer's disease. So, the interactions between the gut and the brain are significantly considered, and also it provides a prominent subject to investigate the causes of some diseases. In this article, we reviewed and focused on the role of the largest and most repetitive bacterial community and their relevance with some diseases that they have mentioned previously.

How Tongxie-Yaofang Regulates Intestinal Synaptic Plasticity by Activating Enteric Glial Cells and NGF/TrkA Pathway in Diarrhea-Predominant Irritable Bowel Syndrome Rats

Purpose

Diarrhea-predominant irritable bowel syndrome (D-IBS) is a frequent functional gastrointestinal disease that affects health and quality of life owing to its high incidence and recurrence rate. Tongxie-Yaofang (TXYF) is a traditional Chinese medicine prescribed for D-IBS. However, the therapeutic mechanism of TXYF has not been fully elucidated. This study aimed to investigate the effects of TXYF on visceral hypersensitivity in stress-induced D-IBS rats and the underlying mechanisms.

Methods

Electromyographic (EMG) activity of the external oblique muscles and the abdominal withdrawal reflex (AWR) score captured by Barostat were used to quantify the effect of TXYF on visceral sensitivity. Transmission electron microscopy (TEM) was used to observe the ultrastructure of the enteric nervous system (ENS). For molecular detection, the colonic expression of enteric glial cell's (EGC's) activation markers, glial fibrillary acidic protein (GFAP) and calcium-binding protein S100β, NGF, TrkA, synaptic plasticity-related factors, synaptophysin (SYN) and postsynaptic density-95 (PSD-95), glutamate, glutamate receptors α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR), and N-methyl-D-aspartate receptor (NMDAR) were detected by immunohistochemistry, enzyme-linked immunosorbent assay, and real-time PCR. An ex vivo experiment was conducted to measure the EGC-induced NGF release.

Results

TXYF decreased the EMG activity and AWR scores in rats with D-IBS. Under TEM, TXYF improved the dense and irregular nerve arrangement, narrowed the synaptic cleft, and decreased the number of synaptic vesicles in D-IBS rats. In addition, TXYF decreased the expression of GFAP, S100β, SYN, and PSD-95; down-regulated the levels of NGF, TrkA, and glutamate; and reduced the mRNA expression of AMPAR1, NMDAR1, and NMDAR2B. In an ex vivo experiment, TXYF decreased NGF release in D-IBS rats, and this trend disappeared under EGC inhibition.

Conclusion

TXYF alleviated visceral hypersensitivity in D-IBS rats possibly by improving synaptic plasticity through inhibiting the activity of EGCs and the NGF/TrkA signaling pathway in the colon.

Functional Implications and Clinical Potential of MicroRNAs in Irritable Bowel Syndrome: A Concise Review

MicroRNAs (miRNAs) are tiny (20-24 nucleotides long), non-coding, highly conserved RNA molecules that play a crucial role within the post-transcriptional regulation of gene expression via sequence-specific mechanisms. Since the miRNA transcriptome is involved in multiple molecular processes needed for cellular homeostasis, its altered expression can trigger the development and progression of several human pathologies. In this context, over the last few years, several relevant studies have demonstrated that dysregulated miRNAs affect a wide range of molecular mechanisms associated with irritable bowel syndrome (IBS), a common gastrointestinal disorder. For instance, abnormal miRNA expression in IBS patients is related to the alteration of intestinal permeability, visceral hyperalgesia, inflammatory pathways, and pain sensitivity. Besides, specific miRNAs are differentially expressed in the different subtypes of IBS, and therefore, they might be used as biomarkers for precise diagnosis of these pathological conditions. Accordingly, miRNAs have noteworthy potential as theragnostic targets for IBS. Hence, in this current review, we present an overview of the recent discoveries regarding the clinical relevance of miRNAs in IBS, which might be useful in the future for the development of miRNA-based drugs against this disorder.

Modulation of Intestinal Corticotropin-Releasing Hormone Signaling by the Herbal Preparation STW 5-II: Possible Mechanisms for Irritable Bowel Syndrome Management

Corticotropin-releasing factor (CRF) mediates stress responses and alters the gut-brain axis, contributing to the pathogenesis of irritable bowel syndrome (IBS), which is recognized by abdominal pain accompanied by bowel habit disturbance. STW 5-II, a mixture of six herbal extracts, is clinically effective in functional dyspepsia and IBS. Here we aimed to establish an organoid-based stress-induced IBS-like model to investigate the mechanisms of action of STW 5-II. STW 5-II (10, 20, and 30 g/mL) was applied to intestinal organoids for 24 h before being treated with CRF (100 nM) for 48 h. The effects of STW 5-II on CRF signaling were investigated using several in vitro and in silico approaches. STW 5-II activities were further explored by in silico PyRx screening followed by molecular docking of the main 52 identified compounds in STW 5-II with both CRF receptors CRFR1 and CRFR2. CRF exposure stimulated inflammation and increased proinflammatory mediators, while STW 5-II dose-dependently counteracted these effects. STW 5-II inhibited CRF-induced claudin-2 overexpression and serotonin release. Docking of the STW 5-II constituents oleanolic acid and licorice saponin G2 to CRFR1 and CRFR2, respectively, showed a good affinity. These multi-target activities support and elucidate the clinically proven efficacy of STW 5-II in disorders of gut-brain interaction.

Acupuncture relieves the visceral pain of diarrhea-predominant irritable bowel syndrome rats by regulating P2X4 expression

OBJECTIVES

We researched the effect and mechanism of acupuncture treatment for visceral pain in rats with diarrhea-predominant irritable bowel syndrome (IBS-D).

METHODS

We set up a rat model of IBS-D with chemical and chronic- and acute-pressure stimulations. Then, the IBS-D rats were treated with acupuncture or 5-BDBD, and the therapeutic efficacy of acupuncture in IBS-D rats was assessed by means of the Bristol scale, diarrhea index, abdominal withdrawal reflex (AWR) score, mast cell count and histologic staining.

RESULTS

Acupuncture significantly decreased clinical symptoms in IBS-D rats after a 14 day-treatment. Furthermore, significant down-regulation of P2X4, OX42, BDNF (brain-derived neurotrophic factor) and IRF-5 (interferon regulatory factor 5) expressions were observed in the IBS-D rats, along with the decreased inflammatory factors [interleukin 1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL-6)], chemokines [monocyte chemoattractant protein-1 (MCP-1), regulated on activation, normal T cell expressed and secreted (RANTES), and C-X-C motif chemokine ligand 1 (CXCL1)], and neurotransmitters [substance P (SP), 5-hydroxytryptamine (5-HT), and calcitonin gene-related peptide (CGRP)]. 5-BDBD treatment had a similar effect on IBS-D rats.

CONCLUSIONS

Acupuncture can effectively alleviate abdominal pain by decreasing visceral hypersensitivity and controlling the expression of P2X4 and spinal microglial inflammation in IBS rats.

Bifidobacterium bifidum and Bacteroides fragilis Induced Differential Immune Regulation of Enteric Glial Cells Subjected to Exogenous Inflammatory Stimulation

Enteric glial cells (EGCs) are involved in intestinal inflammation. In this study, we will investigate how Bifidobacterium bifidum (B.b.) and Bacteroides fragilis (B.f.) influence EGC regulation. After pretreatment with lipopolysaccharide (LPS) and interferon-γ (IFN-γ), the expressions of major histocompatibility complex class II (MHC-II), CD80, CD86, glial cell line-derived neurotrophic factor (GDNF), toll-like receptor 2 (TLR-2), and tumor necrosis factor-α (TNF-α) in EGCs were detected using polymerase chain reaction and western blot after co-culture with the supernatants of B.b. or B.f. (multiplicity of infection, 40:1 or 80:1). Finally, EGCs were co-cultured with naive CD₄⁺ T cells, and the expressions of interleukin (IL)-2, IL-4, IL-10, and IL-17 in supernatant were measured using enzyme-linked immunosorbent assay (ELISA). The mRNA expressions of MHC-II and CD86 in EGCs were increased after combined stimulation with LPS and IFN-γ. The expressions of MHC-II, GDNF, TLR-2, and TNF-α were all significantly upregulated in stimulated EGCs. The B.b. supernatant downregulated the expressions of MHC-II, GDNF, TLR-2, and TNF-α in stimulated EGCs, whereas the B.f. supernatant upregulated TLR-2 expression and downregulated MHC-II expression. The expressions of IL-4, IL-2, and IL-17 after co-culture of naive CD₄⁺ T cells and stimulated EGCs were significantly increased. The supernatant of B.b. or B.f. downregulated the expressions of these cytokines. The low-concentration B.b. supernatant upregulated IL-10 expression. Conclusions B.b. and B.f. may influence intestinal inflammation by regulating MHC-II, GDNF, TLR-2, and TNF-α expression in EGCs and IL-4, IL-2, IL-17, and IL-10 secretion.

Cisapride versus Maren Pill for Functional Constipation: A Meta-Analysis

Background

The efficacy and safety of cisapride in functional constipation (FC) remain unclear. This meta-analysis aimed at investigating the efficacy and safety of cisapride and Maren pill in the treatment of FC. Material and Methods. PubMed, Web of Science, Embase, Cochrane Library, WANFANG DATA, VIP, and CNKI databases were searched from inception to December 2021 for eligible comparative studies investigating the effects and safety of cisapride and Maren pill for FC. The primary outcome was the therapeutic effectiveness rate. The secondary outcomes were recurrence rate and incidence of adverse events.

Results

A total of 526 studies were screened out by searching the electronic databases and by manually searching the relevant reference lists. According to the four-step process (identification, screening, eligibility, and inclusion) to select studies for meta-analysis, 521 articles were excluded. Finally, 5 studies with a total of 414 patients with FC were included in the quantitative analysis after sequential exclusion. The cisapride group had a significantly higher effectiveness rate than the control one (90.78% vs 64.97%, P < 0.05). The incidence of adverse events in the cisapride group was lower than that in the Maren pill group (10.08% vs 13.95%, P < 0.05). Similarly, the recurrence rate of the cisapride group was lower than that of the Maren pill group (32.31% vs 53.16%, P < 0.05).

Conclusion

For FC patients, cisapride is more effective than Maren pill; the recurrence rate and adverse event rate are lower than the latter, which makes it a better choice. The combination of cisapride and Maren pill is a direction of future research studies, which may increase the efficiency and reduce the dosage of cisapride.

A Combination of Mediterranean and Low-FODMAP Diets for Managing IBS Symptoms? Ask Your Gut!

Among other factors, food intolerance is cardinal in triggering irritable bowel syndrome (IBS) symptoms in a significant percentage of patients. As a result, specific dietary patterns are the first-line therapeutic approach. The low-FODMAP diet (LFD) is gaining ground as the most well-documented diet intervention that significantly reduces IBS symptoms. Though the LFD improves symptoms, the diet’s impact on intestinal low-grade inflammation, one of the cardinal mechanisms contributing to symptom development, remains doubtful. On the other hand, the Mediterranean diet (MedDiet) is recommended for chronic low-grade inflammation-related diseases because of its anti-inflammatory properties, derived predominantly from olive oil and phenolic compounds. Thus far, the role of a modified LFD, enriched with the MedDiet’s anti-inflammatory components, has not been evaluated in IBS patients. This review aims to examine the hypothesis of a potential combination of the immunomodulatory effects of the MedDiet with the LFD to improve IBS symptoms.

Antibiotics, gut microbiota, and irritable bowel syndrome: What are the relations?

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder in which recurrent abdominal pain is associated with defecation or a change in bowel habits (constipation, diarrhea, or both), and it is often accompanied by symptoms of abdominal bloating and distension. IBS is an important health care issue because it negatively affects the quality of life of patients and places a considerable financial burden on health care systems. Despite extensive research, the etiology and underlying pathophysiology of IBS remain incompletely understood. Proposed mechanisms involved in its pathogenesis include increased intestinal permeability, changes in the immune system, visceral hypersensitivity, impaired gut motility, and emotional disorders. Recently, accumulating evidence has highlighted the important role of the gut microbiota in the development of IBS. Microbial dysbiosis within the gut is thought to contribute to all aspects of its multifactorial pathogenesis. The last few decades have also seen an increasing interest in the impact of antibiotics on the gut microbiota. Moreover, antibiotics have been suggested to play a role in the development of IBS. Extensive research has established that antibacterial therapy induces remarkable shifts in the bacterial community composition that are quite similar to those observed in IBS. This suggestion is further supported by data from cohort and case-control studies, indicating that antibiotic treatment is associated with an increased risk of IBS. This paper summarizes the main findings on this issue and contributes to a deeper understanding of the link between antibiotic use and the development of IBS.

Irritable Bowel Syndrome, Depression, and Neurodegeneration: A Bidirectional Communication from Gut to Brain

Patients with irritable bowel syndrome (IBS) are increasingly presenting with a wide range of neuropsychiatric symptoms, such as deterioration in gastroenteric physiology, including visceral hypersensitivity, altered intestinal membrane permeability, and gastrointestinal motor dysfunction. Functional imaging of IBS patients has revealed several abnormalities in various brain regions, such as significant activation of amygdala, thinning of insular and anterior cingulate cortex, and increase in hypothalamic gray matter, which results in poor psychiatric and cognitive outcomes. Interrelations between the enteric and central events in IBS-related gastrointestinal, neurological, and psychiatric pathologies have compelled researchers to study the gut-brain axis-a bidirectional communication that maintains the homeostasis of the gastrointestinal and central nervous system with gut microbiota as the protagonist. Thus, it can be disrupted by any alteration owing to the gut dysbiosis or loss of diversity in microbial composition. Available evidence indicates that the use of probiotics as a part of a balanced diet is effective in the management of IBS and IBS-associated neurodegenerative and psychiatric comorbidities. In this review, we delineate the pathogenesis and complications of IBS from gastrointestinal and neuropsychiatric standpoints while also discussing the neurodegenerative events in enteric and central nervous systems of IBS patients and the therapeutic potential of gut microbiota-based therapy established on clinical and preclinical data.

Probiotics, Prebiotics, and Synbiotics in the Irritable Bowel Syndrome Treatment: A Review

Irritable bowel syndrome is not a life-threatening disease, yet it significantly affects the quality of life and contributes to economic loss. It is estimated that even up to 45% of the world's population can suffer from the disease. The first attempts to diagnose irritable bowel syndrome were made at the end of the 19th century; however, establishing appropriate diagnostic criteria and treatment methods is still ongoing. To date, little is known about the etiology of irritable bowel syndrome; however, growing attention is drawn to the intestinal microbiota as a factor in the disease development. For this reason, researchers have conducted many studies on therapies that modulate the microbiota, among which probiotics, prebiotics, and synbiotics are widely studied. To date, most studies have examined probiotics; however, there are also several studies demonstrating the efficacy of prebiotics and synbiotics. The aim of this review was to summarize findings on the usefulness of probiotics, prebiotics, and synbiotics in the treatment of irritable bowel syndrome.

Disruption of the pro-inflammatory, anti-inflammatory cytokines and tight junction proteins expression, associated with changes of the composition of the gut microbiota in patients with irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a pathologic condition characterized by changes in gut microbiome composition, low-grade inflammation, and disruption of intestinal wall permeability. The interaction between the gut microbiome and the disease manifestation remains unclear. The changing of tight junction proteins and cytokines expression throughout the gastrointestinal tract in IBS patients has not been studied yet.

AIM OF THE STUDY

To assess the changes of gut microbiome composition, tight junction proteins, and cytokines expression of intestinal mucosa from the duodenum to the distal part of the colon in IBS patients and healthy volunteers.

METHODS

In 31 IBS patients (16 patients with IBS-D; 15 patients with IBS-C) and 10 healthy volunteers the expression of CLD-2, CLD-3, CLD-5, IL-2, IL-10, and TNF-α in mucosal biopsy specimens was determined by morphological and immune-histochemical methods. The qualitative and quantitative composition of the intestinal microbiota was assessed based on 16S rRNA gene sequencing in both groups of patients.

RESULTS

The expression of IL-2 and TNF-α was significantly increased in IBS patients compared with the controls (p<0.001), with a gradual increase from the duodenum to the sigmoid colon. The expression of IL-10, CLD-3, and CLD-5 in mucosal biopsy specimens of these patients was lower than in the control group (p<0.001). Increased ratios of Bacteroidetes and decreased ratios of Firmicutes were noted in IBS patients compared to healthy volunteers (p<0.05).

CONCLUSION

IBS patients have impaired gut permeability and persisting low-grade inflammation throughout the gastrointestinal tract. Changes in the gut microbiota may support or exacerbate these changes.

Efficacy and safety of Bacillus coagulans LBSC in irritable bowel syndrome: A prospective, interventional, randomized, double-blind, placebo-controlled clinical study [CONSORT Compliant]

GOALS

To evaluate safety and efficacy of Bacillus coagulans LBSC [DSM17654] in irritable bowel syndrome (IBS) through a prospective, interventional, randomized, double-blind, and placebo-controlled, CONSORT compliant clinical trial.

BACKGROUND

Bacteriotherapy shows promising impact on alleviating clinical conditions of IBS and associated functional gastrointestinal disorders. B coagulans LBSC is a genetically and phenotypically safe probiotic strain used in this study to study its impact on ameliorating IBS symptoms and improving quality of life.

METHODS

In this interventional, randomized, double-blind, placebo-controlled clinical study, total 40 subjects (18-65 years) were screened through Rome IV criteria and randomized into 2 groups, that is, interventional and placebo arm (n = 20/arm). Similar dosages were received by both the arm, that is, placebo (vehicle) and interventional arm (B coagulans LBSC, 6 billion/d) for a period of 80 days. Study completed with per protocol subjects (n = 38) and results were considered to evaluate the primary and secondary endpoints.

RESULTS

Assessment through Digestive Symptom Frequency Questionnaire 5 point Likert scale showed significant improvement in interventional arm compared to placebo on symptoms such as bloating/cramping, abdominal pain, diarrhea, constipation, stomach rumbling, nausea, vomiting, headache, and anxiety. Maximum of "no symptoms" cases and mild to moderate gastrointestinal symptoms along with improved stool consistency were from interventional arm tested following IBS severity scoring system and Bristol stool form scale. Upper gastrointestinal endoscopy revealed no clinical difference of gastrointestinal mucosa between both the arms. B coagulans LBSC was well tolerated with no serious adverse events.

CONCLUSIONS

B coagulans LBSC was safe for human consumption and efficacious in alleviating overall pathophysiological symptoms of IBS and thereby improving inclusive quality of life evaluated.

Acupuncture for Adults with Diarrhea-Predominant Irritable Bowel Syndrome or Functional Diarrhea: A Systematic Review and Meta-Analysis

Objective. To evaluate the clinical effectiveness and safety of acupuncture therapy in the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D) or functional diarrhea (FD) in adults. Method. Five electronic databases-PubMed, EMBASE, CNKI, VIP, and Wanfang-were searched, respectively, until June 8, 2020. The literature of clinical randomized controlled trials of acupuncture for the treatment of IBS-D or FD in adults were collected. Meta-analysis was conducted by Using Stata 16.0 software, the quality of the included studies was assessed by the RevMan ROB summary and graph, and the results were graded by GRADE. Result. Thirty-one studies with 3234 patients were included. Most of the studies were evaluated as low risk of bias related to selection bias, attrition bias, and reporting bias. Nevertheless, seven studies showed the high risk of bias due to incomplete outcome data. GRADE's assessments were either moderate certainty or low certainty. Compared with loperamide, acupuncture showed more effectiveness in weekly defecation (SMD = -0.29, 95% CI [-0.49, -0.08]), but no significant improvement in the result of the Bristol stool form (SMD = -0.28, 95% CI [-0.68, 0.12]). In terms of the drop-off rate, although the acupuncture group was higher than the bacillus licheniformis plus beanxit group (RR = 2.57, 95% CI [0.24, 27.65]), loperamide group (RR = 1.11, 95% CI [0.57, 2.15]), and trimebutine maleate group (RR = 1.19, 95% CI [0.31, 4.53]), respectively, it was lower than the dicetel group (RR = 0.83, 95% CI [0.56, 1.23]) and affected the overall trend (RR = 0.93, 95% CI [0.67, 1.29]). Besides, acupuncture produced more significant effect than dicetel related to the total symptom score (SMD = -1.17, 95% CI [-1.42, -0.93]), IBS quality of life (SMD = 2.37, 95% CI [1.94, 2.80]), recurrence rate (RR = 0.43, 95% CI [0.28, 0.66]), and IBS Symptom Severity Scale (SMD = -0.75, 95% CI [-1.04, -0.47]). Compared to dicetel (RR = 1.25, 95% CI [1.18, 1.32]) and trimebutine maleate (RR = 1.35, 95% CI [1.13, 1.61]), acupuncture also showed more effective at total efficiency. The more adverse effect occurred in the acupuncture group when comparing with the dicetel group (RR = 11.86, 95% CI [1.58, 89.07]) and loperamide group (RR = 4.42, 95% CI [0.57, 33.97]), but most of the adverse reactions were mild hypodermic hemorrhage. Conclusion. Acupuncture treatment can improve the clinical effectiveness of IBS-D or FD, with great safety, but the above conclusions need to be further verified through the higher quality of evidence.

Gut Microbiota-Bile Acid Crosstalk in Diarrhea-Irritable Bowel Syndrome

The occurrence of diarrhea-predominant irritable bowel syndrome (IBS-D) is the result of multiple factors, and its pathogenesis has not yet been clarified. Emerging evidence indicates abnormal changes in gut microbiota and bile acid (BA) metabolism have a close relationship with IBS-D. Gut microbiota is involved in the secondary BA production via deconjugation, 7α-dehydroxylation, oxidation, epimerization, desulfation, and esterification reactions respectively. Changes in the composition and quantity of gut microbiota have an important impact on the metabolism of BAs, which can lead to the occurrence of gastrointestinal diseases. BAs, synthesized in the hepatocytes, play an important role in maintaining the homeostasis of gut microbiota and the balance of glucose and lipid metabolism. In consideration of the complex biological functional connections among gut microbiota, BAs, and IBS-D, it is urgent to review the latest research progress in this field. In this review, we summarized the alterations of gut microbiota in IBS-D and discussed the mechanistic connections between gut microbiota and BA metabolism in IBS-D, which may be involved in activating two important bile acid receptors, G-protein coupled bile acid receptor 1 (TGR5) and farnesoid X receptor (FXR). We also highlight the strategies of prevention and treatment of IBS-D via regulating gut microbiota-bile acid axis, including probiotics, fecal microbiota transplantation (FMT), cholestyramine, and the cutting-edge technology about bacteria genetic engineering.

The Diagnosis Performance of the TCM Syndromes of Irritable Bowel Syndrome by Gastroenterologists Based on Modified Simple Criteria Compared to TCM Practitioners: A Prospective, Multicenter Preliminary Study

PURPOSE

Traditional Chinese medicine (TCM) including Chinese patent medicine has been widely used to treat irritable bowel syndrome (IBS). Syndrome differentiation is the essence of TCM. However, the diagnostic ability of gastroenterologists to detect TCM syndromes in IBS in China remains unknown. The aim of this study was to investigate the ability of gastroenterologists to diagnose the TCM syndromes of IBS based on modified simple criteria compared with TCM practitioners.

METHODS

Patients meeting the Rome III criteria for IBS-D or IBS-C were recruited from six tertiary referral centers between January 2016 and December 2017. After learning the diagnosis criteria of the TCM syndromes in IBS, gastroenterologists first diagnosed the syndromes of the enrolled patients. Subsequently, the patients were diagnosed by TCM practitioners. The rate of agreement between the gastroenterologists and TCM practitioners was analyzed. In addition, demographic data and the distribution of TCM syndrome types in IBS were also analyzed.

RESULTS

A total of 178 patients (93 males and 85 females), including 131 patients with IBS-D and 47 patients with IBS-C, were enrolled in this study. The rate of agreement of the syndrome diagnosis between the gastroenterologists and TCM practitioners was 84.3%. The diagnosis consistency rates among IBS-D patients and IBS-C patients were 87.0% and 76.5%, respectively. The most common TCM syndrome type in IBS-D patients was liver depression and spleen deficiency syndrome (27.5%), followed by spleen-yang deficiency syndrome (19.8%). Dryness and heat in intestine syndrome was the most common TCM syndrome in IBS-C patients (57.4%).

CONCLUSIONS

Gastroenterologists had good diagnostic agreement with TCM practitioners for diagnosing TCM syndrome types in IBS after learning the diagnostic criteria. This knowledge can aid gastroenterologists in selecting suitable Chinese patent medicine to treat IBS.

Cannabidiol and Other Non-Psychoactive Cannabinoids for Prevention and Treatment of Gastrointestinal Disorders: Useful Nutraceuticals?

Cannabis sativa is an aromatic annual flowering plant with several botanical varieties, used for different purposes, like the production of fibers, the production of oil from the seeds, and especially for recreational or medical purposes. Phytocannabinoids (terpenophenolic compounds derived from the plant), include the well-known psychoactive cannabinoid Δ9-tetrahydrocannabinol, and many non-psychoactive cannabinoids, like cannabidiol. The endocannabinoid system (ECS) comprises of endocannabinoid ligands, enzymes for synthesis and degradation of such ligands, and receptors. This system is widely distributed in the gastrointestinal tract, where phytocannabinoids exert potent effects, particularly under pathological (i.e., inflammatory) conditions. Herein, we will first look at the hemp plant as a possible source of new functional food ingredients and nutraceuticals that might be eventually useful to treat or even prevent gastrointestinal conditions. Subsequently, we will briefly describe the ECS and the general pharmacology of phytocannabinoids. Finally, we will revise the available data showing that non-psychoactive phytocannabinoids, particularly cannabidiol, may be useful to treat different disorders and diseases of the gastrointestinal tract. With the increasing interest in the development of functional foods for a healthy life, the non-psychoactive phytocannabinoids are hoped to find a place as nutraceuticals and food ingredients also for a healthy gastrointestinal tract function.