Gut Microbiome and Its Role in the Pathophysiology of Irritable Bowel Syndrome

2021 ◽  
Vol 51 (4) ◽  
Author(s):  
Giada De Palma ◽  
Premysl Bercik

Irritable bowel syndrome is the most common functional gastrointestinal disorder, affecting up to 9% individuals globally. Although the etiology of this syndrome is likely heterogenous, it presents with its hallmark symptoms of abdominal pain and altered intestinal motility. Moreover, it is considered to be a disorder of the gut-brain interaction, and the microbiome has often been implicated as a central player in its pathophysiology. Patients with irritable bowel syndrome display altered composition and function of the gut microbiota compared to healthy controls. Microbiome directed therapies, such as probiotics, antibiotics and fecal microbiome transplantation, appear to be beneficial for both gut symptoms and psychiatric comorbidities. This review aims to recapitulate the available literature on the microbiome contribution to the pathophysiology and symptoms presentation of irritable bowel syndrome, as well as the current literature on microbiome-targeted treatments for this disease.

2021 ◽  
pp. 155982762110129
Author(s):  
Andrew Thomas ◽  
Annie Thomas ◽  
Madeline Butler-Sanchez

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.


2021 ◽  
Vol 14 ◽  
pp. 175628482199358
Author(s):  
Nikita Hanning ◽  
Adam L. Edwinson ◽  
Hannah Ceuleers ◽  
Stephanie A. Peters ◽  
Joris G. De Man ◽  
...  

Background and Aim: Irritable bowel syndrome (IBS) is a complex and heterogeneous disorder. Sensory, motor and barrier dysfunctions are the key physiological endophenotypes of IBS. Our aim is to review studies evaluating barrier dysfunction in adults and children with IBS, as well as to link those changes with IBS symptomatology and quality of life. Methods: A comprehensive and systematic review of multiple databases was performed up to March 2020 to identify studies comparing intestinal permeability in IBS patients with healthy controls. Both in vivo and in vitro studies were considered. Results: We identified 66 studies, of which 27 used intestinal probes to quantify barrier function. The prevalence of barrier dysfunction differed between PI-IBS (17–50%), IBS-D (37–62%) and IBS-C (4–25%). At a group level, permeability was increased compared with healthy controls in IBS-D (9/13 studies) and PI-IBS (4/4 studies), but only a minority of IBS-C (2/7 studies) and not in the only IBS-M study. All four studies in children with IBS demonstrated loss of barrier function. A heterogeneous set of tight junction genes were found to be altered in small and large intestines of adults with IBS, but these have not been evaluated in children. Positive associations were identified between barrier dysfunction and bowel disturbances (6/9 studies), abdominal pain (9/13 studies), overall symptom severity (1/6 studies), depression and anxiety (1/1 study) and quality of life (1/4 studies). Fecal slurry or supernatants of IBS patients were found to induce barrier disruption in animal models (5/6 studies). Conclusions: Barrier dysfunction is present in a significant proportion of adult and all pediatric IBS studies, especially in the IBS-D and PI-IBS subtype. The majority of studies indicated a positive association between loss of barrier function and symptoms such as abdominal pain and changes in the bowel function.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yue Hu ◽  
Fang Chen ◽  
Haiyong Ye ◽  
Bin Lu

AbstractStress is one of the major causes of irritable bowel syndrome (IBS), which is well-known for perturbing the microbiome and exacerbating IBS-associated symptoms. However, changes in the gut microbiome and metabolome in response to colorectal distention (CRD), combined with restraint stress (RS) administration, remains unclear. In this study, CRD and RS stress were used to construct an IBS rat model. The 16S rRNA gene sequencing was used to characterize the microbiota in ileocecal contents. UHPLC-QTOF-MS/MS assay was used to characterize the metabolome of gut microbiota. As a result, significant gut microbial dysbiosis was observed in stress-induced IBS rats, with the obvious enrichment of three and depletion of 11 bacterial taxa in IBS rats, when compared with those in the control group (q < 0.05). Meanwhile, distinct changes in the fecal metabolic phenotype of stress-induced IBS rats were also found, including five increased and 19 decreased metabolites. Furthermore, phenylalanine, tyrosine and tryptophan biosynthesis were the main metabolic pathways induced by IBS stress. Moreover, the altered gut microbiota had a strong correlation with the changes in metabolism of stress-induced IBS rats. Prevotella bacteria are correlated with the metabolism of 1-Naphthol and Arg.Thr. In conclusion, the gut microbiome, metabolome and their interaction were altered. This may be critical for the development of stress-induced IBS.


2022 ◽  
Vol 25 (8) ◽  
pp. 864-873
Author(s):  
A. Y. Tikunov ◽  
A. N. Shvalov ◽  
V. V. Morozov ◽  
I. V. Babkin ◽  
G. V. Seledtsova ◽  
...  

To date, the association of an imbalance of the intestinal microbiota with various human diseases, including both diseases of the gastrointestinal tract and disorders of the immune system, has been shown. However, despite the huge amount of accumulated data, many key questions still remain unanswered. Given limited data on the composition of the gut microbiota in patients with ulcerative colitis (UC) and irritable bowel syndrome (IBS) from different parts of Siberia, as well as the lack of data on the gut microbiota of patients with bronchial asthma (BA), the aim of the study was to assess the biodiversity of the gut microbiota of patients with IBS, UC and BA in comparison with those of healthy volunteers (HV). In this study, a comparative assessment of the biodiversity and taxonomic structure of gut microbiome was conducted based on the sequencing of 16S rRNA genes obtained from fecal samples of patients with IBS, UC, BA and volunteers. Sequences of the Firmicutes and Bacteroidetes types dominated in all samples studied. The third most common in all samples were sequences of the Proteobacteria type, which contains pathogenic and opportunistic bacteria. Sequences of the Actinobacteria type were, on average, the fourth most common. The results showed the presence of dysbiosis in the samples from patients compared to the sample from HVs. The ratio of Firmicutes/Bacteroidetes was lower in the IBS and UC samples than in HV and higher the BA samples. In the samples from patients with intestinal diseases (IBS and UC), an increase in the proportion of sequences of the Bacteroidetes type and a decrease in the proportion of sequences of the Clostridia class, as well as the Ruminococcaceae, but not Erysipelotrichaceae family, were found. The IBS, UC, and BA samples had signif icantly more Proteobacteria sequences, including Methylobacterium, Sphingomonas, Parasutterella, Halomonas, Vibrio, as well as Escherichia spp. and Shigella spp. In the gut microbiota of adults with BA, a decrease in the proportion of Roseburia, Lachnospira, Veillonella sequences was detected, but the share of Faecalibacterium and Lactobacillus sequences was the same as in healthy individuals. A signif icant increase in the proportion of Halomonas and Vibrio sequences in the gut microbiota in patients with BA has been described for the f irst time.


Nutrients ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 2048 ◽  
Author(s):  
Hanna Fjeldheim Dale ◽  
Stella Hellgren Rasmussen ◽  
Özgün Ömer Asiller ◽  
Gülen Arslan Lied

Irritable bowel syndrome (IBS) is a frequent functional gastrointestinal disorder, and alterations in the gut microbiota composition contributes to symptom generation. The exact mechanisms of probiotics in the human body are not fully understood, but probiotic supplements are thought to improve IBS symptoms through manipulation of the gut microbiota. The aim of this systematic review was to assess the latest randomized controlled trials (RCTs) evaluating the effect of probiotic supplementation on symptoms in IBS patients. A literature search was conducted in Medline (PubMed) until March 2019. RCTs published within the last five years evaluating effects of probiotic supplements on IBS symptoms were eligible. The search identified in total 35 studies, of which 11 met the inclusion criteria and were included in the systematic review. Seven studies (63.6%) reported that supplementation with probiotics in IBS patients significantly improved symptoms compared to placebo, whereas the remaining four studies (36.4%) did not report any significant improvement in symptoms after probiotic supplementation. Of note, three studies evaluated the effect of a mono-strain supplement, whereas the remaining eight trials used a multi-strain probiotic. Overall, the beneficial effects were more distinct in the trials using multi-strain supplements with an intervention of 8 weeks or more, suggesting that multi-strain probiotics supplemented over a period of time have the potential to improve IBS symptoms.


BMJ Open ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. e041733
Author(s):  
Paul Moayyedi ◽  
Glenda MacQueen ◽  
Charles N Bernstein ◽  
Stephen Vanner ◽  
Premysl Bercik ◽  
...  

IntroductionGut microbiome and diet may be important in irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and comorbid psychiatric conditions, but the mechanisms are unclear. We will create a large cohort of patients with IBS, IBD and healthy controls, and follow them over time, collecting dietary and mental health information and biological samples, to assess their gastrointestinal (GI) and psychological symptoms in association with their diet, gut microbiome and metabolome.Methods and analysisThis 5-year observational prospective cohort study is recruiting 8000 participants from 15 Canadian centres. Persons with IBS who are 13 years of age and older or IBD ≥5 years will be recruited. Healthy controls will be recruited from the general public and from friends or relatives of those with IBD or IBS who do not have GI symptoms. Participants answer surveys and provide blood, urine and stool samples annually. Surveys assess disease activity, quality of life, physical pain, lifestyle factors, psychological status and diet. The main outcomes evaluated will be the association between the diet, inflammatory, genetic, microbiome and metabolomic profiles in those with IBD and IBS compared with healthy controls using multivariate logistic regression. We will also compare these profiles in those with active versus quiescent disease and those with and without psychological comorbidity.Ethics and disseminationApproval has been obtained from the institutional review boards of all centres taking part in the study. We will develop evidence-based knowledge translation initiatives for patients, clinicians and policymakers to disseminate results to relevant stakeholders.Trial registration number:NCT03131414


2020 ◽  
Vol 13 ◽  
pp. 175628481989753 ◽  
Author(s):  
William D. Chey ◽  
Eric D. Shah ◽  
Herbert L. DuPont

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder with a multifactorial pathophysiology. The gut microbiota differs between patients with IBS and healthy individuals. After a bout of acute gastroenteritis, postinfection IBS may result in up to approximately 10% of those affected. Small intestinal bacterial overgrowth (SIBO) is more common in patients with IBS than in healthy individuals, and eradication of SIBO with systemic antibiotics has decreased symptoms of IBS in some patients with IBS and SIBO. The nonsystemic (i.e. low oral bioavailability) antibiotic rifaximin is indicated in the United States and Canada for the treatment of adults with IBS with diarrhea (IBS-D). The efficacy and safety of 2-week single and repeat courses of rifaximin have been demonstrated in randomized, placebo-controlled studies of adults with IBS. Rifaximin is widely thought to exert its beneficial clinical effects in IBS-D through manipulation of the gut microbiota. However, current studies indicate that rifaximin induces only modest effects on the gut microbiota of patients with IBS-D, suggesting that the efficacy of rifaximin may involve other mechanisms. Indeed, preclinical data reveal a potential role for rifaximin in the modulation of inflammatory cytokines and intestinal permeability, but these two findings have not yet been examined in the context of clinical studies. The mechanism of action of rifaximin in IBS is likely multifactorial, and further study is needed.


2019 ◽  
Vol 12 ◽  
pp. 175628481988642 ◽  
Author(s):  
Qihong Yu ◽  
Xinru Liu ◽  
Haojie Huang ◽  
Xingfeng Zheng ◽  
Xue Pan ◽  
...  

Background: Irritable bowel syndrome (IBS) is a common gastrointestinal disorder without obvious structural abnormalities or consistent associated biomarkers, making its diagnosis difficult. In the present study, we used a urine-based metabolomics approach to identify IBS biomarkers. Methods: We used an ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) on urine samples from patients suffering from IBS and healthy controls. Data were coupled for multivariate statistical analysis methods. Results: We selected 30 differential metabolites associated with IBS and found steroid hormone biosynthesis and histidine metabolism alterations in patients with IBS that may be involved in the pathogenesis of the disease. In addition, we identified a panel of five metabolite markers composed of cortisone, citric acid, tiglylcarnitine, N6,-N6,-N6-trimethyl-L-lysine and L-histidine that could be used to discriminate between patients and healthy controls and may be appropriate as IBS diagnosis biomarkers. Conclusion: Our findings indicate that metabolomics combined with pattern recognition can be useful to identify disease diagnostic IBS markers. Clinical trial registration: ChiCTR1800020072


2021 ◽  
Author(s):  
Joann Phan ◽  
Divya Nair ◽  
Suneer Jain ◽  
Thibaut Montagne ◽  
Demi Valeria Flores ◽  
...  

AbstractBackgroundIrritable bowel syndrome (IBS) is characterized by abdominal discomfort and irregular bowel movements and stool consistency. Because there are different symptoms associated with IBS, it is difficult to diagnose the role of the microbiome in IBS.ObjectiveHere, we present a study that includes metagenomic sequencing of stool samples from subjects with the predominant subtypes of IBS and a healthy cohort. We collected longitudinal samples from individuals with IBS who took daily made-to-order precision probiotic and prebiotic supplementation throughout the study.Materials and MethodsThis study includes a population of 489 individuals with IBS and 122 healthy controls. All stool samples were subjected to shotgun metagenomic sequencing. Precision probiotics and prebiotics were formulated for all subjects with longitudinal timepoints.ResultsThere was significant variation explained in the microbiome between the healthy and IBS cohorts. Individuals with IBS had a lower gut microbiome diversity and reduced anti-inflammatory microbes compared to the healthy controls. Eubacterium rectale and Faecalibacterium prausnitzii were associated with healthy microbiomes while Shigella species were associated with IBS. Pathway analysis indicated a functional imbalance of short chain fatty acids, vitamins, and a microbial component of Gram-negative bacteria in IBS compared to healthy controls. In the longitudinal dataset, there was a significant difference in microbiome composition between timepoints 1 and 3. There was also a significant increase in the overall microbiome score and relative abundances of probiotic species used to target the symptoms associated with IBS.ConclusionsWe identified microbes and pathways that differentiate healthy and IBS microbiomes. In response to precision probiotic supplementation, we identified a significant improvement in the overall microbiome score in individuals with IBS. These results suggest an important role for probiotics in managing IBS symptoms and modulation of the microbiome as a potential management strategy.ImportanceAn estimated 35 million people in the United States and 11.5% of the population globally are affected by IBS. Immunity, genetics, environment, diet, small intestinal bacterial overgrowth (SIBO), and the gut microbiome are all factors that contribute to the onset or triggers of IBS. With strong supporting evidence that the gut microbiome may influence symptoms associated with IBS, elucidating the important microbes that contribute to the symptoms and severity is important to make decisions for targeted treatment. As probiotics have become more common in treating IBS symptoms, identifying effective probiotics may help inform future studies and treatment.


2011 ◽  
Vol 140 (2) ◽  
pp. 323-328 ◽  
Author(s):  
J. YAKOOB ◽  
Z. ABBAS ◽  
M. A. BEG ◽  
S. NAZ ◽  
R. KHAN ◽  
...  

SUMMARYWe determined the prevalence of Entamoeba (E.) histolytica, E. dispar and E. moshkovskii in patients with chronic diarrhoea associated with abdominal pain or discomfort mimicking irritable bowel syndrome. Stool samples were collected from 161 patients with chronic diarrhoea and from 157 healthy controls. Stool microscopy with modified trichrome stain, culture and polymerase chain reaction (PCR) for Entamoeba spp. differentiation was performed. Microscopy demonstrated Entamoeba cysts in 44% (57/129) of patients with diarrhoea compared to 29% (44/151) of controls (P=0·009). In patients with diarrhoea, PCR for E. histolytica was positive in 9% (11/129) (P=0·008), E. dispar in 19% (24/129) (P=0·117) and E. moshkovskii in 19% (24/129) (P<0·001). E. histolytica and E. moshkovskii were significantly associated with diarrhoea while E. dispar was found equally in both groups.


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