Modulation of the gut microbiota: a focus on treatments for irritable bowel syndrome

A New Strategy for Dietary Nutrition to Improve Intestinal Homeostasis in Diarrheal Irritable Bowel Syndrome: A Perspective on Intestinal Flora and Intestinal Epithelial Interaction

BACKGROUND AND OBJECTIVES

Although a reasonable diet is essential for promoting human health, precise nutritional regulation presents a challenge for different physiological conditions. Irritable Bowel Syndrome (IBS) is characterized by recurrent abdominal pain and abnormal bowel habits, and diarrheal IBS (IBS-D) is the most common, seriously affecting patients' quality of life. Therefore, the implementation of precise nutritional interventions for IBS-D has become an urgent challenge in the fields of nutrition and food science. IBS-D intestinal homeostatic imbalance involves intestinal flora disorganization and impaired intestinal epithelial barrier function. A familiar interaction is evident between intestinal flora and intestinal epithelial cells (IECs), which together maintain intestinal homeostasis and health. Dietary patterns, such as the Mediterranean diet, have been shown to regulate gut flora, which in turn improves the body's health by influencing the immune system, the hormonal system, and other metabolic pathways.

METHODS

This review summarized the relationship between intestinal flora, IECs, and IBS-D. It analyzed the mechanism behind IBS-D intestinal homeostatic imbalance by examining the interactions between intestinal flora and IECs, and proposed a precise dietary nutrient intervention strategy.

RESULTS AND CONCLUSION

This increases the understanding of the IBS-D-targeted regulation pathways and provides guidance for designing related nutritional intervention strategies.

Irritable Bowel Syndrome in the Elderly Population: A Comprehensive Review

Irritable bowel syndrome (IBS) is a fairly common functional digestive disorder; it occurs at any age but it is more common in adults and older adults. Patients experience a series of symptoms in which abdominal pain and changes in bowel movements stand out; some studies have revealed a possible association between IBS and psychological problems, such as anxiety and depression. Recent findings point to disorders of gut-brain interaction, disruption and alteration of gut microbiota and dysbiosis as key factors in the etiopathogenesis of IBS; aging is also one the factors involved. Most patients diagnosed with IBS required pharmacotherapy, greater caution needs to be considered when treating older patients because of the risk-benefit profile in the elderly. In this scenario, probiotics and non-pharmacological treatments appear as safe and accessible options. Clinicians must take into consideration the unique biopsychosocial factors in older adults when treating IBS. We aim to review critically recent literature on the topic of IBS as there is a need for consolidated guidelines.

Global research states and trends of micro RNA in irritable bowel syndrome: a bibliometric analysis

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder, but its diagnosis and treatment remain obscure. Non-coding RNAs (ncRNAs), as potential biomarkers, have attracted increasing attention in digestive diseases. Here, we present a comprehensive research status, development trends, and valuable insights in this subject area. The literature search was performed using Web of Science Core Collection. VOSviewer 1.6.20, Citespace 6.2.R4, and Microsoft Excel 2021 were used for bibliometric analysis. A total of 124 articles were included in the analysis. Overall, publication patterns fluctuated. Globally, People's Republic of China, the USA, and Germany were the top three contributors of publications. Guangzhou University of Chinese Medicine, University of California, Mayo Clinic, and University of California, Los Angeles contributed the highest number of publications. The pathways and specific mechanisms by which ncRNAs regulate transcription and translation and thus regulate the pathophysiological processes of IBS are the main research hotspots in this field. We found that microRNA (miRNAs) are intricately involved in the regulation of key pathologies such as viscera sensitivity, intestinal permeability, intestinal mucosal barrier, immunoinflammatory response, and brain-gut axis in the IBS, and these topics have garnered significant attention in research community. Notably, microecological disorders are also associated with IBS pathogenesis, and ncRNA may play an important role in the interactions between host and intestinal flora. This is the first bibliometric study to comprehensively summarize the research hotspots and trends related to IBS and ncRNAs (especially miRNAs). Our findings will help understand the role of ncRNAs in IBS and provide guidance to future studies.

Effectiveness of a Balanced Nine-Strain Synbiotic in Primary-Care Irritable Bowel Syndrome Patients-A Multi-Center, Randomized, Double-Blind, Placebo-Controlled Trial

The aim of the study was to characterize effects of a multi-strain synbiotic in patients with moderate to severe irritable bowel syndrome (IBS) of all stool form types. A total of 202 adult IBS patients were randomized (1:1) and after a four-week treatment-free run-in phase and were treated either with the synbiotic or a placebo for 12 weeks. The primary endpoints were the assessment of the severity of IBS symptoms (IBS-SSS) and the improvement of IBS global symptoms (IBS-GIS). Secondary endpoints comprised adequate relief (IBS-AR scale), stool form type (Bristol Stool Form Scale), bowel movements, severity of abdominal pain and bloating, stool pressure, feeling of incomplete stool evacuation, and adverse events. A total of 201 patients completed the study. Synbiotic treatment, in comparison to placebo, significantly improved IBS-SSS and IBS-GIS scores. At the end of the treatment, 70% of patients in the synbiotic group achieved adequate relief. After 12 weeks of treatment, the secondary endpoints were favorably differentiated in the synbiotic group when compared with the placebo group. Two patients in the synbiotic group reported transient adverse events (headache). The results indicate that treatment of IBS patients with the synbiotic significantly improved all major symptoms of IBS and was well-tolerated. The ClinicalTrials.gov registration was NCT05731232.

Probiotics: Health benefits, food application, and colonization in the human gastrointestinal tract

Probiotics have become increasingly popular over the past two decades due to the continuously expanding scientific evidence indicating their beneficial effects on human health. Therefore, they have been applied in the food industry to produce functional food, which plays a significant role in human health and reduces disease risk. However, maintaining the viability of probiotics and targeting the successful delivery to the gastrointestinal tract remain two challenging tasks in food applications. Specifically, this paper reviews the potentially beneficial properties of probiotics, highlighting the use and challenges of probiotics in food application and the associated health benefits. Of foremost importance, this paper also explores the potential underlying molecular mechanisms of the enhanced effect of probiotics on gastrointestinal epithelial cells, including a discussion on various surface adhesion‐related proteins on the probiotic cell surface that facilitate colonization.

Modulation of microbiota as a target in the management of patients with irritable bowel syndrome

Irritable  bowel syndrome  (IBS) is one of the  most common  diseases  of the  digestive  tract. IBS negatively  affects  the  quality of life and work ability of patients. It is generally  accepted that  IBS is an important medical  and social problem  associated with high financial  costs  both  on the  part of the  patient  and the  public health  system. The pathophysiology of the  disease involves the participation of many factors (genetic, dietary, psychosocial, infectious) and the mechanisms of their implementation, including  disruption  of interaction along  the  functional  “gut-brain axis”, visceral  hypersensitivity,  changes  in motility, low-grade  inflammation, increased permeability of the epithelial intestinal barrier, modulation of microbiota, changes  in neurohumoral  regulation and  processes of central  processing  of peripheral stimuli. Research  shows  an important role  for gut microbiota  in the development of IBS. Modulation of the intestinal microbiota  through  diet, the use of pre- and probiotics  or fecal microbiota transplantation is considered as a promising target  for disease  therapy. A reduction  in the number of bacteria of the genus  Bifidobacterium is described  as a universal  change  in the microbiota  in IBS, regardless of the clinical course and severity of the disease  and the possibility of using different  strains of Bifidobacterium in treatment regimens  for the disease  is of particular  interest. This article  provides  a review of the literature on modern  approaches to prescribing  probiotics  for IBS. Using our own clinical observations as an example, we demonstrated the effectiveness and safety of prolonged administration of the probiotic strain Bifidobacterium longum 35624®  for up to 12 weeks.

Yeast Peptides Improve the Intestinal Barrier Function and Alleviate Weaning Stress by Changing the Intestinal Microflora Structure of Weaned Lambs

Early weaning stress in lambs leads to decreased feed intake, damage to intestinal morphology, changes in the microbial flora structure, and subsequent complications. Yeast peptides are antimicrobial peptides with anti-inflammatory, antioxidant, and bacteriostasis effects. To study the effects of yeast peptides on relieving weaning stress in lambs, 54 lambs were randomly divided into three groups: ewe-reared (ER), yeast-peptide-treated (AP), and early-weaned (EW) lambs. The body weight and dry matter intake did not significantly differ among all groups. After weaning, the daily gain and feed conversion rate decreased significantly (p < 0.01), but AP showed an upward trend. In the EW group, immunoglobulin (Ig) levels changed significantly post-weaning (IgG decreased; IgA and IgM increased); the villi shortened, the crypt depth increased, and the villi height/crypt depth decreased (p < 0.001). The abundance and diversity of microflora among all groups were not significantly different. A column coordinate analysis showed significant differences in the intestinal microbial structure between the AP and EW groups. Lactobacillus, Aeriscardovia, Ruminosaceae_UCG-014, and Catenisphaera may play key roles in alleviating weaning stress in lambs. Our study provides new clues for alleviating weaning stress in lambs by describing the influence of yeast peptides on the intestinal microflora during weaning.

Exploring the Role of Vitamin D and the Gut Microbiome: A Cross-Sectional Study of Individuals with Irritable Bowel Syndrome and Healthy Controls

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction with multifaceted pathophysiology. Prior studies have demonstrated higher rates of vitamin D deficiency in individuals with IBS compared to healthy controls (HC), as well as associations of vitamin D concentration with IBS symptoms. A systematic review of 10 mouse and 14 human studies reported a positive association between vitamin D (serum levels and supplementation) and beta diversity of gut microbiome in a variety of conditions. The present retrospective case-control study aimed to compare vitamin D (25(OH)D) plasma concentrations and gut microbiome composition in adult women with IBS (n=99) and HC (n=62). Plasma concentrations of 25(OH)D were assessed using the Endocrine Society Guidelines definition of vitamin D deficiency (25(OH)D <20 ng/ml) and insufficiency (25(OH)D >20-<30 ng/ml). 16S rRNA microbiome gene sequencing data was available for 39 HC and 62 participants with IBS. Genus-level Bifidobacterium and Lactobacillus and phylum-level Firmicutes and Bacteroidetes relative abundances were extracted from microbiome profiles. Results showed vitamin D deficiency in 40.3% (n=25) vs. 41.4% (n=41), and insufficiency 33.9% (n=21) vs. 34.3% (n=34) in the HCs vs. IBS groups, respectively. The odds of IBS did not differ depending on 25(OH)D status (p=0.75 for deficient, p=0.78 for insufficient), and the average plasma vitamin D concentration did not differ between IBS (mean 24.8 ng/ml) and HCs (mean 25.1 ng/ml; p=0.57). We did not find evidence of an association between plasma 25(OH)D concentration and richness, Shannon index, Simpson index or specific bacterial abundances in either HCs or the IBS group.

Sonchus arvensis L. water extract attenuates dextran sulfate sodium-induced colitis by adjusting gut microbiota

Sonchus arvensisL. (SA) is a traditional Chinese food and medicine termed "Ju Mai Cai". The aim of this study was to investigate the protective effects of an aqueous extract of SA on dextran sulfate sodium (DSS) - induced colitis in mice by adjusting the diversity of gut microbiota. Male C57BL/6 mice were randomly divided into four groups: CL (control group); ML group (DSS only); SA group (SA extract); and MS group (SA extract + DSS). The protective effect of SA on ulcerative disease was estimated by several analyses (i.e., body weight loss, diarrhea, bloody stools, disease activity index scores, and hematoxylin and eosin staining). The effect of SA on gut microbiota was determined by analysis of the 16S ribosomal RNA gene sequences. The results indicated that MS significantly attenuated the body weight loss. The disease activity index scores were markedly lower in the MS group versus in the ML group. Moreover, the length of the colon was significantly improved in the MS groups versus in the ML group. Pathological changes were markedly improved following the administration of SA to mice with DSS-induced ulcerative disease. The results of Beta diversity analysis revealed that the composition of gut microbiota was significantly different between groups. Taken together, the results indicated that SA extract may prevent ulcerative colitis.

The Short-term Efficacy of Bifidobacterium Quadruple Viable Tablet in Patients with Diarrhea-Predominant Irritable Bowel Syndrome: Potentially Mediated by Metabolism rather than Diversity Regulation

OBJECTIVES

The therapeutic effect of probiotics for irritable bowel syndrome (IBS) was controversial. This study aims to evaluate the short-term efficacy of Bifidobacterium quadruple viable tablet in patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and explore factors associated with response to probiotics.

METHODS

A randomized, double-blind, placebo-controlled, multicenter trial was performed in 15 hospitals. 290 patients who fulfilled the eligibility criteria were assigned to the probiotics or placebo group randomly with a ratio of 1:1 for a 4-week treatment and a 2-week follow-up. The primary outcome was the response rate. It was regarded as the proportion of patients with composite responses of improvement in both abdominal pain and diarrhea simultaneously.

RESULTS

After 4-week continuous administration, the response rate of the probiotics and the placebo were 67.59% and 36.55% respectively (p<0.001). In the probiotics, those with higher abdominal pain scores (2.674 [1.139, 6.279]) were more likely to respond but responders in placebo had lower Hamilton Depression Scale (HAMD) score (0.162 [0.060, 0.439]), lower Hamilton Anxiety Scale (HAMA) score (0.335 [0.148, 0.755]) and higher degree of bloating (2.718 [1.217, 6.074]). Although the diversity of the microbiota was not significantly changed by probiotics, the abundance of bacteria producing short chain fatty acids (SCFAs) including Butyricimonas (p=0.048), Pseudobutyrivibrio (p=0.005), Barnesiella (p=0.020) and Sutterella (p=0.020), and the concentration of SCFAs including butyric acid (p=0.010), valeric acid (p=0.019) and caproic acid (p=0.046) in feces increased.

CONCLUSIONS

Bifidobacterium quadruple viable tablet had a significant short-term efficacy for the treatment of IBS-D, and were more effective in patients with higher abdominal pain scores. This kind of probiotics could improve the abundance of several bacteria producing SCFAs as well as the concentration of fecal SCFAs compared to placebos.

Care of Patients With Transthyretin Amyloidosis: the Roles of Nutrition, Supplements, Exercise, and Mental Health

Transthyretin (ATTR) amyloidosis is a debilitating disease that results in organ failure and eventual death. As the disease progresses, patients experience neurologic, gastrointestinal, and cardiovascular symptoms that increasingly compromise their nutritional status and exercise capacity. These symptoms cause considerable emotional stress and mental health challenges for patients and caregivers. This review summarizes common symptoms and mechanisms associated with malnutrition and exercise intolerance, and sources of emotional stress, and offers therapeutic strategies to address these issues. Although earlier diagnosis and disease-specific treatment are central to caring for patients with ATTR amyloidosis, additional attention to symptom-focused treatments to improve nutritional status, maintain exercise tolerance and capacity, and improve and maintain mental health are also important. In conclusion, a team-based approach involving multiple clinicians and providers can offer more comprehensive and coordinated care, support, and education for patients and caregivers.

Interaction between the Gut Microbiota and Intestinal Motility

The gut microbiota is the largest symbiotic ecosystem with the host and has been proven to play an important role in maintaining the stability of the intestinal environment. The imbalance of the gut microbiota is caused by the imbalance between the symbiotic microbiota and the pathogenic microbiota. The commensal microbiome regulates intestinal motility, while the pathogenic microbiome causes intestinal motility disorder, resulting in disease development. Intestinal motility is a relatively general term, and its meaning may include intestinal muscle contraction, intestinal wall biomechanics, intestinal compliance, and transmission. The role of intestinal microecology and intestinal motility are interrelated, intestinal flora disorder mediates intestinal motility, and abnormal intestinal motility affects colonization of the intestinal flora. In this review, we briefly outlined the interaction between gut microbiota and intestinal motility and provided a reference for future studies.

Dietary Modification for the Restoration of Gut Microbiome and Management of Symptoms in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder leading to chronic debilitating issues. A healthy diet plays an integral role in maintaining the gut microbiota equilibrium, thus promoting digestive health. The structure and function of gut microbiota are affected by genetics and environmental factors, such as altered dietary habits, gastroenteritis, stress, increased use of alcohol and drugs, and medication use. Whereas there are various management approaches cited in the literature to manage symptoms of IBS, the purpose of this article is to focus on dietary options that will restore the gut microbiome and help in managing IBS symptoms. Some of the diets that are discussed in this article include a low-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet, gluten-free/wheat-free diet, high-fiber diet, dietary and herbal supplements (psyllium, peppermint oil), and probiotics/prebiotics/synbiotics. The clinical practice guidelines recommended by the American College of Gastroenterology outlines evidence-based dietary recommendations for patients with IBS to manage symptoms. Recent advancements in the dietary management of IBS highlighting the use of a patient-centered, personalized nutrition approach along with lifestyle changes, pharmacological therapies, and psychosocial and behavioral interventions are also reviewed and discussed.

Wumei pills attenuates 5-fluorouracil-induced intestinal mucositis through Toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-κB pathway and microbiota regulation

BACKGROUND

Radiotherapy and chemotherapy can kill tumor cells and improve the survival rate of cancer patients. However, they can also damage normal cells and cause serious intestinal toxicity, leading to gastrointestinal mucositis[1]. Traditional Chinese medicine is effective in improving the side effects of chemotherapy. Wumei pills (WMP) was originally documented in the Treatise on Exogenous Febrile Diseases. It has a significant effect on chronic diarrhea and other gastrointestinal diseases, but it is not clear whether it affects chemotherapy-induced intestinal mucositis (CIM).

AIM

To explore the potential mechanism of WMP in the treatment of CIM through experimental research.

METHODS

We used an intraperitoneal injection of 5-fluorouracil (5-Fu) to establish a CIM mouse model and an oral gavage of WMP decoction (11325 and 22650 mg/kg) to evaluate the efficacy of WMP in CIM. We evaluated the effect of WMP on CIM by observing the general conditions of the mice (body weight, food intake, spleen weight, diarrhea score, and hematoxylin and eosin stained tissues). The expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β, and myeloperoxidase (MPO), as well as the Toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-κB (TLR4/MyD88/NF-κB) signaling pathway proteins and tight junction proteins (zonula occludens-1, claudin-1, E-cadherin, and mucin-2) was determined. Furthermore, intestinal permeability, intestinal flora, and the levels of short-chain fatty acids (SCFA) were also assessed.

RESULTS

WMP effectively improved the body weight, spleen weight, food intake, diarrhea score, and inflammatory status of the mice with intestinal mucositis, which preliminarily confirmed the efficacy of WMP in CIM. Further experiments showed that in addition to reducing the levels of TNF-α, IL-1β, IL-6, and MPO and inhibiting the expression of the TLR4/MyD88/NF-κB pathway proteins, WMP also repaired the integrity of the mucosal barrier of mice, regulated the intestinal flora, and increased the levels of SCFA (such as butyric acid).

CONCLUSION

WMP can play a therapeutic role in CIM by alleviating inflammation, restoring the mucosal barrier, and regulating gut microbiota.

Probiotics and Functional Gastrointestinal Disorders in Pediatric Age: A Narrative Review

Assessment and management of pain are essential components of pediatric care. Pain in pediatric age is characterized by relevant health and socio-economic consequences due to parental concern, medicalization, and long-term physical and psychological impact in children. Pathophysiological mechanisms of nociception include several pathways in which also individual perception and gut-brain axis seem to be involved. In this narrative review, we analyze the rational and the current clinical findings of probiotic use in the management of functional gastrointestinal disorders (FGID) in pediatric age, with special focus on infantile colic, irritable bowel syndrome, constipation, and gastroesophageal reflux. Some specific probiotics showed a significant reduction in crying and fussing compared to placebo in breastfed infants with colic, although their exact mechanism of action in this disorder remains poorly understood. In irritable bowel syndrome, a limited number of studies showed that specific strains of probiotics can improve abdominal pain/discomfort and bloating/gassiness, although data are still scarce. As for constipation, whilst some strains appear to reduce the number of hard stools in constipated children, the evidence is not adequate to support the use of probiotics in the management of functional constipation. Similarly, although some probiotic strains could promote gastric emptying with a potential improvement of functional symptoms related to gastroesophageal reflux, current evidence is insufficient to provide any specific recommendation for the prevention or treatment of gastroesophageal reflux. In conclusion, probiotics have been proposed as part of management of pain in functional gastrointestinal disorders in pediatric age, but mechanisms are still poorly understood and evidence to guide clinical practice is currently inadequate.

Dyspepsia and Gut Microbiota in Female Patients with Postcholecystectomy Syndrome

BACKGROUND

Gallstone disease (GSD) represents one of the most frequent digestive disorders, highly reported in female gender. The purpose of the study was to explore the clinical and gut microbiota particularities of female patients with postcholecystectomy syndrome (PCS) and the possible relationship between gut dysbiosis (DB) and abdominal complaints.

PATIENTS AND METHODS

In total, 129 female participants: 104 outpatients divided into two equal groups, 52 PCS (+), 52 PCS (-) and 25 healthy controls were consecutively enrolled in this observational study. Patients underwent clinical examination with assessment of pain, bloating, transit disturbances, abdominal ultrasound/computer tomography/magnetic resonance imaging/endoscopic retrograde cholangiopancreatography, upper and lower digestive endoscopies. Laboratory work-ups and stool microbiology assessments were performed for all study participants (patients and controls). Stool microorganisms were identified by matrix-assisted laser desorption ionization - time-of-flight- mass spectrometry and in patients with DB also by next-generation sequencing.

RESULTS

Older age, complicated gallstones disease, associated conditions like diabetes mellitus/impaired glucose tolerance and irritable bowel syndrome were significantly present in PCS (+) group, as well as sedentary lifestyle and diets characterized by a low fiber intake (p<0.0001). PCS (+) patients displayed significant differences related to the incidence and severity of overall gut microbiota DB, decreased H index of biodiversity and the unbalanced Firmicutes/Bacteroidetes (F/B) ratios by comparison to the PCS (-) group (p<0.0001). Strong positive correlations of the severity of overall DB with bloating and the intestinal habit disorders, as well as of F/B ratios to all abdominal symptoms were noted.

CONCLUSION

PCS in female patients was associated with older age, sedentary lifestyle, specific dietary habits, history of complicated gallstone disease, diabetes mellitus/impaired glucose tolerance and irritable bowel syndrome, as well as gut microbiota particularities. Overall DB and unbalanced F/B ratios were strongly correlated to abdominal complaints.

Preventive and Therapeutic aspects of Fermented Foods

In recent times, the status of some fermented foods which are considered as functional foods that confer health benefits in certain disease conditions has grown rapidly. The health benefits of fermented foods are due to the presence of probiotic microbes and the bioactive compound formed during fermentation. Microbes involved and metabolites produced by them are highly species-specific and contribute to the authenticity of the fermented foods. Several studies pertaining to the effect of fermented foods on various disease conditions have been conducted in recent years using both animal models and clinical trials on humans. This review focuses on the impact of fermented foods on conditions like diabetes, cardiovascular disease (CVD), obesity, gastrointestinal disorder, cancer and neurodegenerative disorders.

Advancement of Traditional Chinese Medicine in Regulation of Intestinal Flora: Mechanism-based Role in Disease Management

Intestinal microecology is the largest and most complex human microecology. The intestinal microflora plays an important role in human health. Imbalance of intestinal microflora contributes to the occurrence and development of many diseases. Recently, the treatment of human diseases by regulating intestinal microflora has become a research topic of interest. Traditional Chinese medicine considers the whole human body as the central concept in disease treatment strategies. It advocates maintaining the coordination and balance of the functions of various organs and systems of the human body, including the intestinal microflora. Traditional Chinese medicine improves the metabolism and immune function of the human body by regulating the intestinal microflora. The intestinal microflora could trigger pharmacological activity or reduce toxicity of drugs through regulating metabolism, which enables traditional Chinese medicine formulations to exert their best therapeutic effects. This review summarized the relationship between the intestinal microflora and digestive system, tumors, and other diseases. Furthermore, the role of traditional Chinese medicine in the treatment of tumors, and other diseases is discussed. The relationship among traditional Chinese medicine and the common intestinal microflora, pathogenesis of human diseases, and effective intervention methods were elaborated. In addition, we explored the research progress of traditional Chinese medicine in the treatment of various human diseases by regulating intestinal microflora to provide new treatment concepts. There is a close relationship between traditional Chinese medicine and the intestinal microflora. Traditional Chinese medicine formulations contribute to maintain the natural balance of the intestinal tract and the intestinal microflora to achieve treatment effects. This paper summarizes the mechanism of action of traditional Chinese medicine formulations in regulating the intestinal microflora in the prevention and treatment of various diseases. Furthermore, it summarizes information on the application of the interaction between traditional Chinese medicine preparations and the regulation of intestinal microflora in the treatment of common human diseases. Intestinal microflora plays a key role in traditional Chinese medicine in maintaining the natural balance of physiology and metabolism of human body. It will provide a theoretical basis for the traditional Chinese medicine preparations in the prevention and treatment of common human diseases, and simulate future research on this aspect.

Crosstalk Between Intestinal Serotonergic System and Pattern Recognition Receptors on the Microbiota-Gut-Brain Axis

Disruption of the microbiota-gut-brain axis results in a wide range of pathologies that are affected, from the brain to the intestine. Gut hormones released by enteroendocrine cells to the gastrointestinal (GI) tract are important signaling molecules within this axis. In the search for the language that allows microbiota to communicate with the gut and the brain, serotonin seems to be the most important mediator. In recent years, serotonin has emerged as a key neurotransmitter in the gut-brain axis because it largely contributes to both GI and brain physiology. In addition, intestinal microbiota are crucial in serotonin signaling, which gives more relevance to the role of the serotonin as an important mediator in microbiota-host interactions. Despite the numerous investigations focused on the gut-brain axis and the pathologies associated, little is known regarding how serotonin can mediate in the microbiota-gut-brain axis. In this review, we will mainly discuss serotonergic system modulation by microbiota as a pathway of communication between intestinal microbes and the body on the microbiota-gut-brain axis, and we explore novel therapeutic approaches for GI diseases and mental disorders.

Early Evidence Indicates Vitamin D Improves Symptoms of Irritable Bowel Syndrome: Nursing Implications and Future Research Opportunities

Irritable bowel syndrome (IBS) affects approximately 11.2% of the population. Yet, full understanding of its etiology and optimal treatment remains elusive. Understanding of the underlying pathophysiology of IBS has been limited. However, research is beginning to identify the cause as multifactorial (e.g., low-grade local mucosal inflammation, systemic immune activation, altered intestinal permeability, intestinal hypersensitivity, altered central nervous system processing, changes in intestinal microbiota). Understanding of the role of vitamin D in intestinal inflammation, immunity, and gastrointestinal conditions is increasing but is not yet fully understood. Growing evidence has linked vitamin D deficiency with a variety of gastrointestinal disorders, including inflammatory bowel disease, diverticulitis, colorectal cancer, and IBS. Several studies have demonstrated that individuals with IBS are more likely to have vitamin D deficiency than healthy controls. Recent vitamin D supplementation studies have shown improvement in quality of life and reduction in IBS symptoms (including abdominal pain, distention, flatulence, constipation, and visceral sensitivity) but the mechanism remains unclear. Nurses are well positioned to educate patients about the importance of sufficient vitamin D for overall health in individuals with IBS as well as participate in well-designed therapeutic studies to explore whether enhanced vitamin D status will ultimately help treat IBS more effectively.

Enteric Microbiota-Mediated Serotonergic Signaling in Pathogenesis of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic functional disorder that affects the gastrointestinal tract. Details regarding the pathogenesis of IBS remain largely unknown, though the dysfunction of the brain-gut-microbiome (BGM) axis is a major etiological factor, in which neurotransmitters serve as a key communication tool between enteric microbiota and the brain. One of the most important neurotransmitters in the pathology of IBS is serotonin (5-HT), as it influences gastrointestinal motility, pain sensation, mucosal inflammation, immune responses, and brain activity, all of which shape IBS features. Genome-wide association studies discovered susceptible genes for IBS in serotonergic signaling pathways. In clinical practice, treatment strategies targeting 5-HT were effective for a certain portion of IBS cases. The synthesis of 5-HT in intestinal enterochromaffin cells and host serotonergic signaling is regulated by enteric resident microbiota. Dysbiosis can trigger IBS development, potentially through aberrant 5-HT signaling in the BGM axis; thus, the manipulation of the gut microbiota may be an alternative treatment strategy. However, precise information regarding the mechanisms underlying the microbiota-mediated intestinal serotonergic pathway related to the pathogenesis of IBS remains unclear. The present review summarizes current knowledge and recent progress in understanding microbiome–serotonin interaction in IBS cases.

Utilizing Probiotics for the Prevention and Treatment of Gastrointestinal Diseases

Probiotics are heavily advertised to promote a healthy gastrointestinal tract and boost the immune system. This review article summarizes the history and diversity of probiotics, outlines conventional in vitro assays and in vivo models, assesses the pharmacologic effects of probiotic and pharmaceutical co-administration, and the broad impact of clinical probiotic utilization for gastrointestinal disease indications.

Probiotics, Photobiomodulation, and Disease Management: Controversies and Challenges

In recent decades, researchers around the world have been studying intensively how micro-organisms that are present inside living organisms could affect the main processes of life, namely health and pathological conditions of mind or body. They discovered a relationship between the whole microbial colonization and the initiation and development of different medical disorders. Besides already known probiotics, novel products such as postbiotics and paraprobiotics have been developed in recent years to create new non-viable micro-organisms or bacterial-free extracts, which can provide benefits to the host with additional bioactivity to probiotics, but without the risk of side effects. The best alternatives in the use of probiotics and postbiotics to maintain the health of the intestinal microbiota and to prevent the attachment of pathogens to children and adults are highlighted and discussed as controversies and challenges. Updated knowledge of the molecular and cellular mechanisms involved in the balance between microbiota and immune system for the introspection on the gut-lung-brain axis could reveal the latest benefits and perspectives of applied photobiomics for health. Multiple interconditioning between photobiomodulation (PBM), probiotics, and the human microbiota, their effects on the human body, and their implications for the management of viral infectious diseases is essential. Coupled complex PBM and probiotic interventions can control the microbiome, improve the activity of the immune system, and save the lives of people with immune imbalances. There is an urgent need to seek and develop innovative treatments to successfully interact with the microbiota and the human immune system in the coronavirus crisis. In the near future, photobiomics and metabolomics should be applied innovatively in the SARS-CoV-2 crisis (to study and design new therapies for COVID-19 immediately), to discover how bacteria can help us through adequate energy biostimulation to combat this pandemic, so that we can find the key to the hidden code of communication between RNA viruses, bacteria, and our body.

Impact of the factors shaping gut microbiota on obesity

Obesity is considered as a risk factor for chronic health diseases such as heart diseases, cancer and diabetes 2. Reduced physical activities, lifestyle, poor nutritional diet and genetics are among the risk factors associated with the development of obesity. In recent years, several studies have explored the link between the gut microbiome and the progression of diseases including obesity, with the shift in microbiome abundance and composition being the main focus. The alteration of gut microbiome composition affects both nutrients metabolism and specific gene expressions, thereby disturbing body physiology. Specifically, the abundance of fibre-metabolizing microbes is associated with weight loss and that of protein and fat-metabolizing bacteria with weight gain. Various internal and external factors such as genetics, maternal obesity, mode of delivery, breastfeeding, nutrition, antibiotic use and the chemical compounds present in the environment are known to interfere with the richness of the gut microbiota (GM), thus influencing weight gain/loss and ultimately the development of obesity. However, the effectiveness of each factor in potentiating the shift in microbes' abundance to result in significant changes that can lead to obesity is not yet clear. In this review, we will highlight the factors involved in shaping GM, their influence on obesity and possible interventions. Understanding the influence of these factors on the diversity of the GM and how to improve their effectiveness on disease conditions could be keys in the treatment of metabolic diseases.

Altered Gut Microbiota in Irritable Bowel Syndrome and Its Association with Food Components

The interplay between diet and gut microbiota has gained interest as a potential contributor in pathophysiology of irritable bowel syndrome (IBS). The purpose of this study was to compare food components and gut microbiota patterns between IBS patients and healthy controls (HC) as well as to explore the associations of food components and microbiota profiles. A cross-sectional study was conducted with 80 young adults with IBS and 21 HC recruited. The food frequency questionnaire was used to measure food components. Fecal samples were collected and profiled by 16S rRNA Illumina sequencing. Food components were similar in both IBS and HC groups, except in caffeine consumption. Higher alpha diversity indices and altered gut microbiota were observed in IBS compared to the HC. A negative correlation existed between total observed species and caffeine intake in the HC, and a positive correlation between alpha diversity indices and dietary fiber in the IBS group. Higher alpha diversity and gut microbiota alteration were found in IBS people who consumed caffeine more than 400 mg/d. Moreover, high microbial diversity and alteration of gut microbiota composition in IBS people with high caffeine consumption may be a clue toward the effects of caffeine on the gut microbiome pattern, which warrants further study.

Quorum sensing: a new prospect for the management of antimicrobial-resistant infectious diseases

INTRODUCTION

Quorum-sensing (QS) is a microbial cell-to-cell communication system that utilizes small signaling molecules to mediates interactions between cross-kingdom microorganisms, including Gram-positive and -negative microbes. QS molecules include N-acyl-homoserine-lactones (AHLs), furanosyl borate, hydroxyl-palmitic acid methylester, and methyl-dodecanoic acid. These signaling molecules maintain the symbiotic relationship between a host and the healthy microbial flora and also control various microbial virulence factors. This manuscript has been developed based on published scientific papers.

AREAS COVERED

Furanones, glycosylated chemicals, heavy metals, and nanomaterials are considered QS inhibitors (QSIs) and are therefore capable of inhibiting the microbial QS system. QSIs are currently being considered as antimicrobial therapeutic options. Currently, the low speed at which new antimicrobial agents are being developed impairs the treatment of drug-resistant infections. Therefore, QSIs are currently being studied as potential interventions targeting QS-signaling molecules and quorum quenching (QQ) enzymes to reduce microbial virulence.

EXPERT OPINION

QSIs represent a novel opportunity to combat antimicrobial resistance (AMR). However, no clinical trials have been conducted thus far assessing their efficacy. With the recent advancements in technology and the development of well-designed clinical trials aimed at targeting various components of the, QS system, these agents will undoubtedly provide a useful alternative to treat infectious diseases.

Adjunctive treatment with probiotics partially alleviates symptoms and reduces inflammation in patients with irritable bowel syndrome

PURPOSE

Irritable bowel syndrome (IBS) is a functional bowel disorder. This study aimed to assess the effect of a probiotic product (containing Lactobacillus casei Zhang, Lactobacillus plantarum P-8, and Bifdobacterium animalis subsp. lactis V9) as an adjunct to a routine regimen in IBS management.

METHODS

Forty-five patients with IBS were randomized into the probiotic (n = 24) and control (n = 21) groups, receiving the routine regimen with or without probiotics for 28 days, respectively. Serum and fecal samples were collected and analyzed.

RESULTS

The IBS-symptom severity score (P < 0.01), serum levels of IL-6 (P < 0.01) and TNF-α (P < 0.001) were significantly lower in the probiotic group than the control group at day 28. The probiotic adjunctive treatment resulted in significant decreases in some bacterial genera that worsen IBS, such as Bacteroides (P < 0.01), Escherichia (P < 0.05), and Citrobacter (P < 0.05), significant decreases were also observed in some beneficial genera in the control group, including Bifidobacterium (P < 0.05), Eubacterium (P < 0.05), Dorea (P < 0.01), and Butyricicoccus (P < 0.05). Furthermore, significant correlations were found between some monitored parameters and compositional changes in the fecal microbiota, suggesting that the clinical improvement of IBS was likely associated with gut microbiota modulation. The enterotype analysis revealed that the initial fecal microbiota composition could influence clinical outcomes.

CONCLUSIONS

The adjunctive use of probiotics with a routine regimen showed additional clinical effectiveness compared to the routine regimen alone in managing IBS. A pretreatment gut microbiome analysis might help tailor a personalized probiotic regimen to optimize treatment effects.

Sequential laxative-probiotic usage for treatment of irritable bowel syndrome: a novel method inspired by mathematical modelling of the microbiome

The gut microbiome plays an important role in human health. However, its response to external intervention is complex. A previous study showed that the response to Clostridium butyricum (CB) treatment of irritable bowel syndrome (IBS) is heterogeneous. We proposed that mathematical model simulation of the microbiota may help to optimize the management of IBS-associated microbiota. In this study, a novel mathematical non-extinction and defecation normalized (NEDN) model was generated for stable simulation of the dynamic nature of gut microbiota. In silico simulation revealed that a laxative may create a favourable opportunity for Clostridium cluster XIVa to shift the microbiota. An explorative clinical trial was conducted to compare three CB regimens in an IBS cohort: laxative, interval of 2 weeks and CB administration for 2 weeks (L2P); laxative immediately followed by CB administration (LP) for 2 weeks; and CB administration for 2 weeks (P). The LP regimen optimally relieved the IBS symptoms and shifted the microbiota closer to those of the healthy subjects during 2 weeks of CB intake. These results indicate that integration of biological/mathematical approaches and clinical scenarios is a promising method for management of microbiota. Additionally, the optimal effect of sequential laxative-CB usage for IBS treatment warrants further validation.

Clinical trial registration numbers: NCT02254629.

Date of registration: October 2, 2014.

Daily Fermented Whey Consumption Alters the Fecal Short-Chain Fatty Acid Profile in Healthy Adults

Gut microbiota influences many aspects of host health including immune, metabolic, and gut health. We examined the effect of a fermented whey concentrate (FWC) drink rich in L-(+)-Lactic acid, consumed daily, in 18 healthy men (n = 5) and women (n = 13) in free-living conditions.

Objective: The aims of this 6-weeks pilot trial were to (i) identify changes in the gut microbiota composition and fecal short chain fatty acid (SCFA) profile, and (ii) to monitor changes in glucose homeostasis.

Results: Total fecal SCFA (mM) concentration remained constant throughout the intervention. Proportionally, there was a significant change in the composition of different SCFAs compared to baseline. Acetate levels were significantly reduced (−6.5%; p < 0.01), coupled to a significant increase in the relative amounts of propionate (+2.2%; p < 0.01) and butyrate (+4.2%; p < 0.01), respectively. No changes in the relative abundance of any specific bacteria were detected. No significant changes were observed in glucose homeostasis in response to an oral glucose tolerance test.

Conclusion: Daily consumption of a fermented whey product led to significant changes in fecal SCFA metabolite profile, indicating some potential prebiotic activity. These changes did not result in any detectable differences in microbiota composition. Post-hoc analysis indicated that baseline microbiota composition might be indicative of participants likely to see changes in SCFA levels. However, due to the lack of a control group these findings would need to be verified in a rigorously controlled trial. Future work is also required to identify the biological mechanisms underlying the observed changes in microbiota activity and to explore if these processes can be harnessed to favorably impact host health.

Clinical Trial Registration: www.clinicaltrials.gov, identifier NCT03615339; retrospectively registered on 03/08/2018.

A Significant Question in Cancer Risk and Therapy: Are Antibiotics Positive or Negative Effectors? Current Answers and Possible Alternatives

Cancer is predominantly considered as an environmental disease caused by genetic or epigenetic alterations induced by exposure to extrinsic (e.g., carcinogens, pollutants, radiation) or intrinsic (e.g., metabolic, immune or genetic deficiencies). Over-exposure to antibiotics, which is favored by unregulated access as well as inappropriate prescriptions by physicians, is known to have led to serious health problems such as the rise of antibiotic resistance, in particular in poorly developed countries. In this review, the attention is focused on evaluating the effects of antibiotic exposure on cancer risk and on the outcome of cancer therapeutic protocols, either directly acting as extrinsic promoters, or indirectly, through interactions with the human gut microbiota. The preponderant evidence derived from information reported over the last 10 years confirms that antibiotic exposure tends to increase cancer risk and, unfortunately, that it reduces the efficacy of various forms of cancer therapy (e.g., chemo-, radio-, and immunotherapy alone or in combination). Alternatives to the current patterns of antibiotic use, such as introducing new antibiotics, bacteriophages or enzybiotics, and implementing dysbiosis-reducing microbiota modulatory strategies in oncology, are discussed. The information is in the end considered from the perspective of the most recent findings on the tumor-specific and intracellular location of the tumor microbiota, and of the most recent theories proposed to explain cancer etiology on the notion of regression of the eukaryotic cells and systems to stages characterized for a lack of coordination among their components of prokaryotic origin, which is promoted by injuries caused by environmental insults.

Can the FUT 2 Gene Variant Have an Effect on the Body Weight of Patients Undergoing Bariatric Surgery?-Preliminary, Exploratory Study

BACKGROUND

The FUT2 gene (Se gene) encoding the enzyme α-1,2-L-fucosyltransferase 2 seems to have a significant effect on the number and type of bacteria colonizing the intestines.

METHODS

In a group of 19 patients after bariatric surgery, the polymorphism (rs601338) of FUT2 gene was analyzed in combination with body mass reduction, intestinal microbiome (16S RNA sequencing), and short chain fatty acids (SCFA) measurements in stools.

RESULTS

Among the secretors (Se/Se polymorphism of the FUT2 gene rs601338, carriers of GG variant), correlations between waist-hip ratio (WHR) and propionate content and an increase in Prevotella, Escherichia, Shigella, and Bacteroides were observed. On the other hand-in non-secretors (carriers of GA and AA variants)-higher abundance of Enterobacteriaceae, Ruminococcaceae, Enterobacteriaceae, Clostridiales was recorded.

CONCLUSIONS

The increased concentrations of propionate observed among the GG variants of FUT 2 may be used as an additional source of energy for the patient and may have a higher risk of increasing the WHR than carriers of the other variants (GA and AA).

Probiotics' efficacy in paediatric diseases: which is the evidence? A critical review on behalf of the Italian Society of Pediatrics

During the last decade several paediatric studies have been published with different possible indications for probiotics, leading to a global increase of probiotics' market. Nevertheless, different study designs, multiple single/combined strains and small sample size still leave many uncertainties regarding their efficacy. In addition, different regulatory and quality control issues make still very difficult the interpretation of the clinical data. The objective of this review is to critically summarise the current evidence on probiotics' efficacy and safety on a different number of pathologies, including necrotizing enterocolitis, acute infectious diarrhoea, allergic diseases and functional gastrointestinal disorders in order to guide paediatric healthcare professionals on using evidence-based probiotics' strains. To identify relevant data, literature searches were performed including Medline-PubMed, the Cochrane Library and EMBASE databases. Considering probiotics strain-specific effects, the main focus was on individual probiotic strains and not on probiotics in general.

The efficacy of Bifidobacterium quadruple viable tablet in the treatment of diarrhea predominant irritable bowel syndrome: protocol for a randomized, double-blind, placebo-controlled, multicenter trial

Background

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders characterized by recurrent abdominal pain associated with defecation or a change in bowel habits. Leading to significant negative effect on patients’ quality of life and huge financial burden to health system, the management of IBS is a great challenge. Probiotics are considered as an effective therapy; however, in a lack of high-quality evidence of efficacy, no strain- and dose-specific probiotics were recommended in clinical guidelines. This study aims to evaluate the efficacy of the Bifidobacterium quadruple viable tablet in the treatment of IBS-D.

Methods/design

A multicenter randomized controlled trial will be performed in fourteen hospitals. A total of three hundred patients who fulfill the eligibility criteria will be stratified divided into an experimental group and a control group randomly in a ratio of 1:1. The experimental group is treated with the Bifidobacterium quadruple viable tablet while the control group is treated with placebo. All the patients will receive a 4-week treatment and a 2-week follow-up. The primary outcome is the effectiveness in improving abdominal pain and stool consistency; the secondary outcome includes evaluation of overall symptom relief, frequency of defecation, bloating, urgency of defecation, remedial medication, score of IBS-QOL, and changes of microbiota and metabonomics. Physical examination, vital signs, laboratory tests, adverse events, and concomitant medication will be taken into account for intervention safety assessment during the trial.

Discussion

This multicenter randomized controlled trial may provide high-quality evidence on the efficacy of the Bifidobacterium quadruple viable tablet for IBS-D on both physical and mental dimensions in China. To fill the gap of previous probiotic intervention studies, in addition, this study will also present safety assessment which will be a significant emphasis.

Trial registration

ChiCTR1800017721. Registered on 10 August 2018.

Long-Term Exposure to Ceftriaxone Sodium Induces Alteration of Gut Microbiota Accompanied by Abnormal Behaviors in Mice

Background: Growing evidence points out that a disturbance of gut microbiota may also disturb the gut–brain communication. However, it is not clear to what extent the alteration of microbiota composition can modulate brain function, affecting host behaviors. Here, we investigated the effects of gut microbiota depletion on emotional behaviors.

Methods: Mice in the experimental group were orally administered ceftriaxone sodium solution (250 mg/ml, 0.2 ml/d) for 11 weeks. The open-field test and tail-suspension test were employed for the neurobehavioral assessment of the mice. Fecal samples were collected for 16s rDNA sequencing. The serum levels of cytokines and corticosterone were quantified using enzyme-linked immunosorbent assays. The immunohistochemistry method was used for the detection of brain-derived neurotrophic factor (BDNF) and c-Fos protein.

Results: The gut microbiota for antibiotic-treated mice showed lower richness and diversity compared with normal controls. This effect was accompanied by increased anxiety-like, depression-like, and aggressive behaviors. We found these changes to be possibly associated with a dysregulation of the immune system, abnormal activity of the hypothalamic-pituitary-adrenal axis, and an alteration of neurochemistry.

Conclusions: The findings demonstrate the indispensable role of microbiota in the gut–brain communication and suggest that the absence of conventional gut microbiota could affect the nervous system, influencing brain function.

Pectin and inulin stimulated the mucus formation at a similar level: An omics-based comparative analysis

Mucin 2 (MUC2) is the skeleton of colonic mucus that comprises the physical intestinal barrier. Different dietary polysaccharides may affect colonic mucus at different extents. The effect of pectin on MUC2 production is contradictory. To investigate whether and how pectin affected hosts' colonic mucus, the amount of MUC2 in colon, the cecal, mucosal microbiota, and metabolites profiles were analyzed and compared with inulin. The results showed pectin stimulated the production of MUC2 at a similar level to inulin. Both interventions increased the abundance of cecal Lachnospira and Christensenellaceae_R-7_group, and enhanced the production of specific metabolites including soyasapogenol B 24-O-b-d-glucoside, lucyoside Q, trans-EKODE-(E)-Ib, and 1,26-dicaffeoylhexacosanediol. Additionally, pectin increased the relative abundance (RA) of cecal Lactobacillus, and induced less RA of potentially harmful bacteria such as Helicobacter in mucosal microbiota than inulin. In conclusion, we first reported that pectin and inulin stimulated the mucus formation at a similar level. Two genera of cecal bacteria and four metabolites may play an important role in enhancing the production of MUC2. Moreover, the MUC2 production may be unrelated to several traditional health-beneficial bacteria; pectin possibly performed as good as or better than the inulin in rats' gut.

Quyushengxin Formula Causes Differences in Bacterial and Phage Composition in Ulcerative Colitis Patients

Background

Ulcerative colitis (UC) is a chronic inflammatory disease that affects the colon and the rectum. Recently, some studies have shown that microorganisms in the gut play important roles in many chronic diseases such as UC.

Methods

To study the candidate viruses and bacteria involved in UC and to investigate the therapeutic mechanism of Quyushengxin formula (QYSX) in UC patients, metagenomic sequencing was performed on the feces from healthy donors and UC patients before and after QYSX treatment.

Results

QYSX improved the symptoms of UC. In all participants, Caudovirales and Herpesvirales were the most dominant viruses. The abundance of Caudovirales in UC patients was significantly higher than that in the normal controls, while QYSX restored Caudovirales abundance. Furthermore, the abundance of crAssphage was enhanced in UC patients compared with the normal control, while the diversity was then decreased after QYSX treatment. However, there was no significant difference (P > 0.05). Additionally, other non-crAssphage bacteriophages including phiST, SP-10, and phi17:2 were higher in UC patients and QYSX decreased these viruses, while the trends of MED4−213, P-HM1, and P−HM2 were adverse. Interestingly, PhiDP23.1 was only found in UC patients before and after QYSX treatment. In addition, Bifidobacterium, Bacteroidetes, Prevotellaceae, Actinobacteria, and Corynebacteriales were the biomarkers in UC patients after QYSX treatment due to their high abundance. GO terms and KEGG analysis showed that the identified gut microbiome was involved in many biological processes and pathways.

Conclusions

QYSX could regulate disordered gut microbiome and phages, indicating that QYSX has great therapeutic potential for UC.

Duodenal and rectal mucosal microbiota related to small intestinal bacterial overgrowth in diarrhea-predominant irritable bowel syndrome

BACKGROUND AND AIM

Small intestinal bacterial overgrowth (SIBO) has been proposed as an etiologic factor in irritable bowel syndrome, particularly the diarrhea-predominant subtype (IBS-D). We aimed to identify potential intestinal microbial pattern in IBS-D patients with SIBO.

METHODS

Diarrhea-predominant irritable bowel syndrome patients fulfilling Rome III criteria were recruited and randomly divided into an exploratory cohort (57 cases) and a validation cohort (20 cases). SIBO was identified according to standard glucose hydrogen breath test. For 16S rRNA gene sequencing, samples of duodenal mucosa, duodenal fluid, rectal mucosa, and fresh feces were collected and performed. The α and β diversity, as well as differences in microbial composition and function, in SIBO⁺ and SIBO^- IBS-D subjects were evaluated.

RESULTS

The microbial diversity and composition obviously differed between SIBO⁺ and SIBO^- IBS-D in duodenal and rectal mucosa but not in duodenal fluid and fresh feces. For rectal mucosal microbiota, it displayed markedly reduced aerobe and Gram-negative bacteria and increased facultative anaerobe and Gram-positive bacteria, moreover, altered functions of microbial metabolism in SIBO⁺ IBS-D. Significantly higher rectal mucosa-related microbial dysbiosis index was observed in SIBO⁺ IBS-D, and a cut-off value at -0.37 had a sensitivity of 56.55% and specificity of 90.91% to identify the SIBO in IBS-D subjects.

CONCLUSIONS

Mucosal microbiota, rather than luminal bacteria, has a more apparent dysbiosis in SIBO⁺ IBS-D patients relative to those without SIBO. Rectal mucosa-associated microbiota may act as a potential predictor of SIBO in IBS-D patients.

Volatomics in inflammatory bowel disease and irritable bowel syndrome

Volatile organic compounds (VOCs) are produced by the human metabolism, inflammation and gut microbiota and form the basis of innovative volatomics research. VOCs detected through breath and faecal analysis hence serve as attractive, non-invasive biomarkers for diagnosing and monitoring irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). This review describes the clinical applicability of volatomics in discriminating between IBS, IBD and healthy volunteers with acceptable accuracy in breath (70%-100%) and faecal (58%-85%) samples. Promising compounds are propan-1-ol for diagnosing and monitoring of IBD patients, and 1-methyl-4-propan-2-ylcyclohexa-1,4-diene as biomarker for IBS diagnosis. However, these VOCs often seem to be related to inflammation and probably will need to be used in conjunction with other clinical evidence. Furthermore, three interventional studies underlined the potential of VOCs in predicting treatment outcome and patient follow-up. This shows great promise for future use of VOCs as non-invasive breath and faecal biomarkers in personalised medicine. However, properly designed studies that correlate VOCs to IBD/IBS pathogenesis, while taking microbial influences into account, are still key before clinical implementation can be expected.

Gut microbiome composition and risk factors in a large cross-sectional IBS cohort

Objective

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that is difficult to diagnose and treat due to its inherent heterogeneity and unclear aetiology. Although there is evidence suggesting the importance of the microbiome in IBS, this association remains poorly defined. In the current study, we aimed to characterise a large cross-sectional cohort of patients with self-reported IBS in terms of microbiome composition, demographics, and risk factors.

Design

Individuals who had previously submitted a stool sample for 16S microbiome sequencing were sent a comprehensive survey regarding IBS diagnosis, demographics, health history, comorbidities, family history, and symptoms. Log ratio-transformed abundances of microbial taxa were compared between individuals reporting a diagnosis of IBS without any comorbidities and individuals reporting no health conditions. Univariable testing was followed by a multivariable logistic regression model controlling for relevant confounders.

Results

Out of 6386 respondents, 1692 reported a diagnosis of IBS without comorbidities and 1124 reported no health conditions. We identified 3 phyla, 15 genera, and 19 species as significantly associated with IBS after adjustment for confounding factors. Demographic risk factors include a family history of gut disorders and reported use of antibiotics in the last year.

Conclusion

The results of this study confirm important IBS risk factors in a large cohort and support a connection for microbiome compositional changes in IBS pathogenesis. The results also suggest clinical relevance in monitoring and investigating the microbiome in patients with IBS. Further, the exploratory models described here provide a foundation for future studies.

Irritable bowel syndrome and gut microbiota

PURPOSE OF REVIEW

To provide an overview of recent studies exploring the gut microbiota in pathogenesis and treatment of irritable bowel syndrome (IBS).

RECENT FINDINGS

Primary bacterial gut disturbances have been linked to the development and severity of IBS. Dysbiosis, or alteration in the normal intestinal flora, modulates intestinal permeability, inflammation, gut motility and likely quality of life. These biomechanical changes are associated with enteric and central nervous system processing as well. When compared to healthy controls, IBS patients display poor quality of life measures and are at increased risk of depression and anxiety. The severity of psychological and gastrointestinal symptoms in IBS has been linked with a distinct intestinal microbiota signature. Efforts to modulate intestinal dysbiosis in IBS have shown little improvement in large systematic reviews. The low FODMAP diet reduces bacteria, such as Bifidobacterum and Actinobacteria. Although rifaximin improves symptoms, it may only stimulate a transient effect on the gut microbiota. Fecal microbiota transplant does not provide prolonged symptom relief in IBS.

SUMMARY

This review elucidates recent advances in IBS and the gut microbiota. Microbiota changes are one underlying factor in perpetuating global IBS symptoms. The opportunity to exploit this disturbance through treatment modalities requires further investigation.

Deep-Fried Atractylodis Rhizoma Protects against Spleen Deficiency-Induced Diarrhea through Regulating Intestinal Inflammatory Response and Gut Microbiota

According to the theories of traditional Chinese medicine, spleen deficiency often leads to diarrhea, and deep-fried Atractylodis Rhizoma (DAR) is commonly used for the treatment. However, the association between spleen deficiency and diarrhea remains unclear. The present study aimed to investigate the therapeutic effect of DAR for the treatment of diarrhea caused by spleen deficiency and analyze the related mechanisms. It was found that a high dose group of an ethanolic extract of deep-fried Atractylodis Rhizoma (EEDAR-H) significantly inhibited weight loss, diarrhea, and pathological changes in colon tissue induced by rhubarb. EEDAR-H was found to significantly reduce the level of intestinal inflammatory cytokines and increase the expression of gastrointestinal motility hormones. In addition, EEDAR-H significantly increased the expression of aquaporin 3 (AQP3) and aquaporin 8 (AQP8) and restored abnormal water metabolism; Shen-Ling-Bai-Zhu-San (SLBZS) induced the same effect as EEDAR-H. Additional tests on the mechanism found that EEDAR-H and SLBZS promoted the integrity of the intestinal barrier. Both significantly increased the expression of the tight junction protein ZO-1 and Occludin, inhibited the phosphorylation of p38MAPK and MLC, and significantly reduced the expression levels of PAR-2. Analysis of the gut microbiota indicated that overall changes in its structure were reversed after treatment with EEDAR-H or SLBZS, in addition to significant modulation of the abundance of different phyla. At the genus level, EEDAR-H or SLBZS significantly reduced the levels of potential pathogens and increased those of beneficial bacteria.

Detrimental and protective action of microglial extracellular vesicles on myelin lesions: astrocyte involvement in remyelination failure

Microglia are highly plastic immune cells which exist in a continuum of activation states. By shaping the function of oligodendrocyte precursor cells (OPCs), the brain cells which differentiate to myelin-forming cells, microglia participate in both myelin injury and remyelination during multiple sclerosis. However, the mode(s) of action of microglia in supporting or inhibiting myelin repair is still largely unclear. Here, we analysed the effects of extracellular vesicles (EVs) produced in vitro by either pro-inflammatory or pro-regenerative microglia on OPCs at demyelinated lesions caused by lysolecithin injection in the mouse corpus callosum. Immunolabelling for myelin proteins and electron microscopy showed that EVs released by pro-inflammatory microglia blocked remyelination, whereas EVs produced by microglia co-cultured with immunosuppressive mesenchymal stem cells promoted OPC recruitment and myelin repair. The molecular mechanisms responsible for the harmful and beneficial EV actions were dissected in primary OPC cultures. By exposing OPCs, cultured either alone or with astrocytes, to inflammatory EVs, we observed a blockade of OPC maturation only in the presence of astrocytes, implicating these cells in remyelination failure. Biochemical fractionation revealed that astrocytes may be converted into harmful cells by the inflammatory EV cargo, as indicated by immunohistochemical and qPCR analyses, whereas surface lipid components of EVs promote OPC migration and/or differentiation, linking EV lipids to myelin repair. Although the mechanisms through which the lipid species enhance OPC maturation still remain to be fully defined, we provide the first demonstration that vesicular sphingosine 1 phosphate stimulates OPC migration, the first fundamental step in myelin repair. From this study, microglial EVs emerge as multimodal and multitarget signalling mediators able to influence both OPCs and astrocytes around myelin lesions, which may be exploited to develop novel approaches for myelin repair not only in multiple sclerosis, but also in neurological and neuropsychiatric diseases characterized by demyelination.

Diagnosis and treatment of gastrointestinal dysfunction in hereditary TTR amyloidosis

PURPOSE

To review the management of gastrointestinal symptoms in patients with hereditary transthyretin amyloidosis, discussing diagnostic evaluations, assessment of disease progression and therapeutic strategies that could be implemented in routine practice.

METHODS

Literature review. Key search terms included "gastrointestinal symptoms", "autonomic neuropathy", "hereditary transthyretin amyloidosis" and "familial amyloid polyneuropathy".

RESULTS

Gastrointestinal disturbances are a common and serious manifestation of hereditary transthyretin amyloidosis, with significant effects on patients' quality of life and demonstrating a strong association with mortality. Gastrointestinal involvement is more often subclinical in the early stages of the disease, although in some patients gastric and/or bowel abnormalities may be the inaugural symptoms. In both cases, under-recognition, delayed investigation and suboptimal treatment frequently occur. A clear understanding of the mechanisms underlying gastrointestinal dysfunction in hereditary transthyretin amyloidosis is still lacking, but similar to diabetic enteropathy, multiple pathophysiological alterations seem to play a role.

CONCLUSIONS

Early detection and treatment of gastrointestinal disturbances is key to the successful treatment of this devastating disease. Gastroenterologists play a valuable role in both the diagnosis and the timely management of gastrointestinal symptoms in hereditary transthyretin amyloidosis and should, therefore, be part of a multidisciplinary and comprehensive approach to this disorder.

Bacillus spp. Spores-A Promising Treatment Option for Patients with Irritable Bowel Syndrome

Dysbiosis is a condition that can cause various clinical disorders, from gastrointestinal problems to allergies or even cancer. Resetting the microbiota using antibiotics and/or probiotics could be a possible therapy for many diseases. The aim of this study was to evaluate the effects of three treatment regimens in patients with irritable bowel syndrome (IBS). The regimens were short-term rifaximin treatment (10 days) followed by either a nutraceutical agent (G1) or a low- Fermentable, Oligo-, Di-, Monosaccharide and Polyol (FODMAP) diet (24 days) (G3) or treatment with MegaSporeBiotic a mixture of spores of five Bacillus spp. for medium-term (34 days) (G2). Ninety patients with IBS without constipation were enrolled and divided into three groups (G1, G2, G3). Patients in G1 and G3 were evaluated over four visits (baseline/first day (V1), 10 days (V2), 34 days (V3), 60 days (V4)), and, those in G2 over three visits (V1, V3, V4). Severity score, quality of life, and parameters from the rectal volume sensation test were determined. The results demonstrated that patients treated with MegaSporeBiotic, compared with those treated with rifaximin followed by nutraceutical or low-FODMAP diet, had similar severity scores and rectal volume sensation test results for all parameters tested and statistically significant improvement in measurements of quality of life.

The Microbiome and Irritable Bowel Syndrome - A Review on the Pathophysiology, Current Research and Future Therapy

Irritable bowel syndrome (IBS) is a functional disorder which affects a large proportion of the population globally. The precise etiology of IBS is still unknown, although consensus understanding proposes IBS to be of multifactorial origin with yet undefined subtypes. Genetic and epigenetic factors, stress-related nervous and endocrine systems, immune dysregulation and the brain-gut axis seem to be contributing factors that predispose individuals to IBS. In addition to food hypersensitivity, toxins and adverse life events, chronic infections and dysbiotic gut microbiota have been suggested to trigger IBS symptoms in tandem with the predisposing factors. This review will summarize the pathophysiology of IBS and the role of gut microbiota in relation to IBS. Current methodologies for microbiome studies in IBS such as genome sequencing, metagenomics, culturomics and animal models will be discussed. The myriad of therapy options such as immunoglobulins (immune-based therapy), probiotics and prebiotics, dietary modifications including FODMAP restriction diet and gluten-free diet, as well as fecal transplantation will be reviewed. Finally this review will highlight future directions in IBS therapy research, including identification of new molecular targets, application of 3-D gut model, gut-on-a-chip and personalized therapy.

Fecal microbiota transfer for bowel disorders: efficacy or hype?

PURPOSE OF REVIEW

Dysbiosis has been related to the pathophysiology of disorders of - gut-brain interaction (DGBI) including irritable bowel syndrome (IBS) and functional constipation (FC). Accordingly, modulation of gut microbiota has been proposed as a potential treatment for these disorders. Gut microbiota modulation can be effected by probiotics, prebiotics, symbiotics, postbiotics, antibiotics and fecal transplantation (FMT) or bacteriotherapy. The latter is currently used for recurrent or severe Clostridium difficile colitis and has been the focus of recent research in IBS and FC.

RECENT FINDINGS

Several case series reported promising results for FMT in patients with IBS and FC, which prompted the conduction of randomized controlled trials (RCT) in these DGBI.

SUMMARY

Both case series and RCTs are herein discussed. To the best of our knowledge, as of yet, 5 RCTs have been published on IBS and one in FC with slow colonic transit. In IBS, the majority of studies have used the IBS severity scoring system (IBS-SSS) as an outcome measure; however, the selection criteria were different among the trials as well as the route and form of administration of the FMT. Therefore, the results are inconsistent and no conclusion can be drawn. Some studies suggest that the presence of post-infection (PI)-IBS and the baseline microbiota status in the donors could be predictor factors of successful FMT in IBS. In constipation with slow colonic transit, the FMT seems to be more effective, although the data is based on only one RCT. We believe that larger RCTs, controlled with true placebos and considering baseline intestinal microbiota of the study subjects as well as donors' microbiota are still needed before recommending FMT in IBS and/or FC. History of previous GI infection (e.g. PI-IBS) and IBS subtypes should also be taken into account.