Recent developments in the pathophysiology of irritable bowel syndrome

Investigating the causal links between obstructive sleep apnea and gastrointestinal diseases mediated by metabolic syndrome through mendelian randomization

Previous studies have pointed to a potential link between Obstructive Sleep Apnea (OSA) and gastrointestinal diseases, suggesting that this relationship might be influenced by the presence of Metabolic Syndrome. However, the exact role of these factors in determining gastrointestinal diseases has not been thoroughly explored. In our study, we utilized data from the Genome-wide Association Studies (GWAS) database, focusing on OSA, metabolic syndrome characteristics such as Body Mass Index (BMI), waist circumference, triglycerides, cholesterol, hypertension, type 2 diabetes, and common gastrointestinal diseases including chronic gastritis, gastric ulcers, irritable bowel syndrome, colorectal cancer, inflammatory bowel disease, cholecystitis, nonalcoholic fatty liver, and dyspepsia. By applying Single-variable and Multi-variable Mendelian randomization methods, we aimed to assess the correlation between OSA and gastrointestinal diseases and investigate whether this correlation is influenced by metabolic syndrome. Our findings revealed a strong association between OSA and an increased risk of chronic gastritis, gastric ulcers, inflammatory bowel disease, and nonalcoholic fatty liver disease. No significant connections were found with irritable bowel syndrome, colorectal cancer, cholecystitis, or dyspepsia. Additionally, OSA was linked to metabolic syndrome traits like BMI, waist circumference, triglycerides, hypertension, and type 2 diabetes. Further analysis showed that BMI, triglycerides, and hypertension were causally related to inflammatory bowel disease; BMI, waist circumference, hypertension, and type 2 diabetes to nonalcoholic fatty liver disease; and triglycerides, hypertension, and type 2 diabetes to chronic gastritis. The multivariable analysis indicated that hypertension mediates the relationship between OSA and chronic gastritis; BMI, triglycerides, and hypertension mediate the link between OSA and inflammatory bowel disease; and waist circumference mediates the connection between OSA and nonalcoholic fatty liver disease. To wrap up, this finding helps us understand how these issues might be related and stresses the role of metabolic syndrome in preventing them, which could lessen their effect on health.

Proinflammatory Diet Increases the Risk of Irritable Bowel Syndrome: A Prospective Study of 129,408 UK Biobank Participants and Mendelian Randomization Analysis

BACKGROUND

Patients with irritable bowel syndrome (IBS) often have chronic low-grade inflammation in the intestinal mucosa. Some dietary components are known to be associated with inflammation. However, there is currently limited research on the relationship between dietary inflammatory potential and the risk of IBS.

METHODS

A total of 129,408 participants in the UK Biobank were included in this study. Energy-Adjusted Dietary Inflammatory Index (E-DII) based on 26 nutrients and the Empirical Dietary Inflammatory Pattern (EDIP) based on 17 food groups were constructed, and on the basis of the tertiles, the continuous score was categorized into proinflammatory, neutral, and antiinflammatory categories. Associations between IBS and E-DII and EDIP were investigated by multivariable Cox proportional hazard models. Potential confounders including sociodemographic, lifestyle, body mass index (BMI), psychological state, type 2 diabetes, and thyroiditis were adjusted. In addition, subgroup analysis and sensitivity analysis were also performed. Finally, a two-sample Mendelian randomization (MR) analysis was employed to explore the independent causality of nutrients and dietary-derived serum antioxidants with IBS.

RESULTS

In the cohort study, over a median follow-up period of 13.26 years, 2421(1.87%) participants developed IBS. In the E-DII categories, after adjusting for the confounders, individuals in the proinflammatory diet category had a higher risk of IBS compared with the antiinflammatory category (HR 1.15, 95% CI 1.03-1.28, p = 0.015, p trend = 0.017) and neutral category (HR 1.13, 95% CI 1.01-1.26, p = 0.030, p trend = 0.017). In the EDIP categories, after adjusting for the confounders, individuals in the proinflammatory diet category had a higher risk of IBS compared with antiinflammatory category (HR 1.19, 95% CI 1.06-1.33, p = 0.002, p trend = 0.002) but no significant association compared with neutral category (HR 1.10, 95% CI 0.99-1.23, p = 0.067, p trend = 0.002). In the MR analysis, genetically determined intake levels of 16 nutrients and 6 dietary sources of circulating antioxidants did not have a causal effect on IBS.

CONCLUSIONS

Our findings indicate that proinflammatory dietary components are independent risk factors for IBS. However, there is no causal relationship between individual nutrient intake or serum antioxidants from dietary sources and IBS.

The role of miRNA in IBS pathogenesis, diagnosis and therapy: The latest thought

IBS is a prevalent clinical condition affecting bowel function. There is a restricted comprehension of its pathogenesis, an absence of particular diagnostic tools, and an insufficiency of efficient pharmacological remedies. MiRNAs are a highly conserved class of non-coding small molecule RNAs, with a length of 20-24 nucleotides. Research has shown the presence of a number of differentially expressed miRNAs in the colonic tissue and peripheral blood of IBS patients. Meanwhile, miRNAs have a critical role in gene expression and the pathology of IBS as they act as significant mediators of post-transcriptional gene silencing. The investigation of miRNA molecular regulatory networks proves useful in examining the convoluted pathogenesis of IBS. This paper presents a review of recent literature on miRNAs associated with IBS, explains how miRNAs contribute to the development of IBS, and assesses the potential usefulness of miRNA analysis for diagnosing and treating IBS.

Gut microbial signatures of patients with diarrhea-predominant irritable bowel syndrome and their healthy relatives

AIMS

Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder, encompassing diarrhea-predominant irritable bowel syndrome (IBS-D). Here, we utilized 16S rDNA gene sequencing to identify potential microbial drivers of IBS-D.

METHODS AND RESULTS

A total of 30 healthy relatives and 27 patients with IBS-D were recruited. Clinical data and fecal samples were collected from patients and controls. 16S rDNA gene sequencing was performed to obtain fecal bacterial data. Differences in community composition were evaluated utilizing analysis of similarity (ANOSIM) using Bray-Curtis dissimilarity. The Wilcoxon rank sum test was used to compare differences in taxa and functional pathways. Finally, the key gut microbiota was identified using the random forest algorithm. Gut microbiota diversity, estimated through the Observe, Chao1, and abundance-based coverage estimator (ACE) indices, was significantly lower in the IBS-D patients than in the healthy relatives. ANOSIM analysis further confirmed significant differences in the composition of the gut microbiota between IBS-D patients and healthy relatives, with an R value of 0.106 and a P-value of 0.005. Notably, the IBS-D patients exhibited a significant enrichment of specific bacterial genera, including Fusicatenibacter, Streptococcus, and Klebsiella, which may possess potential pathogenic properties. In particular, the bacterial genus Klebsiella demonstrated a positive correlation with irritable bowel syndrome severity scoring system scores. Conversely, healthy subjects showed enrichment of bacterial genera such as Alistipes, Akkermansia, and Dialister, which may be beneficial bacteria in IBS-D. Utilizing the random forest model, we developed a discriminative model for IBS-D based on differential bacterial genera. This model exhibited impressive performance, with an area under the curve value of 0.90. Additionally, our analysis did not reveal any gender-specific differences in the microbiota community composition among IBS-D patients.

CONCLUSIONS

Our findings offer preliminary insights into the potential relationship between intestinal microbiota and IBS-D. The identification model for IBS-D, grounded in gut microbiota, holds promising prospects for improving early diagnosis of IBS-D.

Increasing the transplant dose and repeating faecal microbiota transplantation results in the responses of male patients with IBS reaching those of females

BACKGROUND

Faecal microbiota transplantation (FMT) performed with a proper protocol is a safe treatment for IBS that has high efficacy and durable effects. Females have been reported to respond better than males to FMT. The present study aimed at determining whether increasing the transplant dose or repeating FMT improve the responses of males to FMT.

METHODS

This study included 186 IBS patients (131 females and 55 males) who were randomized at a 1:1:1 ratio to receive 90 g of donor faeces once into the large intestine, once into the small intestine or twice into the small intestine. Patients completed five questionnaires that assessed their symptoms and quality of life, and provided faecal samples at baseline and at 3, 6 and 12 months after FMT. The faecal bacterial profile and dysbiosis index were determined using 16S rRNA gene PCR DNA amplification covering variable genes V3-V9.

RESULTS

The response rates to FMT at all observation times did not differ significantly between females and males regardless of the transplant administration route or whether it was repeated. Faecal Alistipes levels were higher in females than in males at baseline and increased in both females and males after FMT. In the repeated group, the Alistipes levels did not differ between females and males after FMT.

CONCLUSIONS

Increasing the transplant dose and repeating FMT results in the responses of male IBS patients to FMT reaching those of females regardless of the administration route. Alistipes spp. levels appear to play a role in this improvement.www.clinicaltrials.gov (NCT04236843).

The Use of Pictograms in the Evaluation of Functional Abdominal Pain Disorders in Children

OBJECTIVE

To evaluate whether the use of pictograms improves symptom evaluation for children with functional abdominal pain disorders (FAPDs).

STUDY DESIGN

This survey study was conducted in 2 academic centers and included patients aged 8-18 years visiting the outpatient clinic for FAPD symptom evaluation. Patients were randomized to fill out the questionnaire without or with accompanying pictograms to assess gastrointestinal symptoms. Afterwards, patients underwent clinical health assessment by the healthcare professional (HCP). Subsequently, the HCP filled out the same questionnaire without pictograms, while blinded to the questionnaire completed by the patient. Primary outcome was the level of agreement between identified symptoms as assessed by patients and HCP.

RESULTS

We included 144 children (questionnaire without accompanying pictograms [n = 82] and with accompanying pictograms [n = 62]). Overall agreements rates were not significantly different (without pictograms median, 70% vs with pictograms median, 70%). Accompanying pictograms did not significantly improve the assessment of abdominal pain symptoms. Accompanying pictograms were beneficial for concordance rates for nausea and vomiting symptoms (without pictograms median, 67% vs with pictograms median, 100%; P = .047). Subgroup analyses for children aged 8-12 years of age revealed similar results (concordance on the presence of nausea and vomiting without pictograms median, 67% vs with pictograms median, 100%; P = .015). Subgroup analyses for children ages 12-18 years showed no significant differences in concordance rates.

CONCLUSIONS

Pictograms do not seem to improve the assessment of FAPDs. However, the use of pictograms improves the evaluation of nausea and vomiting, especially for children aged 8-12 years. Therefore, HCPs could consider using pictograms in that setting during consultations.

Serine proteases and metalloproteases are highly increased in irritable bowel syndrome Tunisian patients

Serine proteases are involved in many biological processes and are associated with irritable bowel syndrome (IBS) pathology. An increase in serine protease activity has been widely reported in IBS patients. While most of the studies focused on host proteases, the contribution of microbial proteases are poorly studied. In the present study, we report the analysis of proteolytic activities in fecal samples from the first Tunisian cohort of IBS-M patients and healthy individuals. We demonstrated, for the first time, that metalloproteases activities were fourfold higher in fecal samples of IBS patients compared to controls. Of interest, the functional characterization of serine protease activities revealed a 50-fold increase in trypsin-like activities and a threefold in both elastase- and cathepsin G-like activities. Remarkably, we also showed a fourfold increase in proteinase 3-like activity in the case of IBS. This study also provides insight into the alteration of gut microbiota and its potential role in proteolytic modulation in IBS. Our results stressed the impact of the disequilibrium of serine proteases, metalloproteases and gut microbiota in IBS and the need of the further characterization of these targets to set out new therapeutic approaches.

Intestinal bacteria associated with irritable bowel syndrome and chronic fatigue

The etiology of irritable bowel syndrome (IBS) is unknown. Abnormal intestinal bacterial profiles and low bacterial diversity appear to play important roles in the pathophysiology of IBS. This narrative review was designed to present recent observations made relating to fecal microbiota transplantation (FMT), which implicate possible roles of 11 intestinal bacteria in the pathophysiology of IBS. The intestinal abundances of nine of these bacteria increased after FMT in patients with IBS, and these increases were inversely correlated with IBS symptoms and fatigue severity. These bacteria were Alistipes spp., Faecalibacterium prausnitzii, Eubacterium biforme, Holdemanella biformis, Prevotella spp., Bacteroides stercoris, Parabacteroides johnsonii, Bacteroides zoogleoformans, and Lactobacillus spp. The intestinal abundances of two bacteria were decreased in patients with IBS after FMT and were correlated with the severity of IBS symptoms and fatigue (Streptococcus thermophilus and Coprobacillus cateniformis). Ten of these bacteria are anaerobic and one (Streptococcus thermophilus) is facultative anaerobic. Several of these bacteria produce short-chain fatty acids, especially butyrate, which is used as an energy source by large intestine epithelial cells. Moreover, it modulates the immune response and hypersensitivity of the large intestine and decreases intestinal cell permeability and intestinal motility. These bacteria could be used as probiotics to improve these conditions. Protein-rich diets could increase the intestinal abundance of Alistipes, and plant-rich diet could increase the intestinal abundance of Prevotella spp., and consequently improve IBS and fatigue.

A systematic review, pairwise meta-analysis and network meta-analysis of randomized controlled trials exploring the role of fecal microbiota transplantation in irritable bowel syndrome

BACKGROUND

Treatment is a challenge in Irritable Bowel Syndrome (IBS) and fecal microbiota transplantation (FMT) has attracted significant interest. Network meta-analysis (NWM) has been established as an evidence-synthesis tool that incorporates direct and indirect evidence in a collection of randomized controlled trials (RCTs) comparing therapeutic intervention competing for similar therapeutic results. No NWM exists concerning the comparative effectiveness and safety of various FMT modalities for IBS.

AIM

We updated pairwise meta-analyses published in the past and assessed the comparative effectiveness and safety of various FMT delivery modalities for IBS.

METHODS

Pairwise meta-analyses and Bayesian NWM were performed. Heterogeneity, consistency of results and publication bias were explored.

RESULTS

Of 510 titles raised by initial search, seven RCTs were entered into meta-analyses and NWM. They included 470 patients and controls, in whom four FMT delivery modalities were used, that is via colonoscopy, nasojejunal tube, duodenoscope and capsules per os. In the pairwise meta-analysis, the pooled results showed that overall FMT was not superior to placebo, whereas the subgroup analyses showed that FMT via duodenoscope and nasojejunal tube was superior. The NWM showed that 60-g FMT via duodenoscope had the highest efficacy (OR, 26.38; 95% CI, 9.22-75.51) and was by far the highest in the efficacy ranking (SUCRA, 98.8%).

CONCLUSION

The pooled results showed no overall advantage of FMT over placebo in IBS. However, upper GI delivery (via duodenoscopy or nasojejunal tube) proved to be effective. Consequently, well-designed RCTs are needed to ensure the efficacy and safety profile before FMT can be applied in everyday clinical practice for IBS patients.

Irritable bowel syndrome patients who are not likely to respond to fecal microbiota transplantation

BACKGROUND

Fecal microbiota transplantation (FMT) interventions have recently been advocated to not succeed in every irritable bowel syndrome (IBS) patient, since the outcome of FMT varies with the IBS subset. This study investigated the factors potentially affecting FMT response using the same patient cohort used in our previous study.

METHODS

This study included 109 patients who received allogenic FMT. Patients completed five questionnaires that assessed their symptoms and quality of life at baseline and at 2 weeks, 1 month, and 3 months after FMT. Patients also provided fecal samples at baseline and 1 month after FMT. The fecal bacterial profile and dysbiosis index (DI) were determined using 16S rRNA gene PCR DNA amplification covering variable genes V3-V9. Response to FMT was defined as a decrease of ≥50 points in the total IBS-SSS score after FMT.

RESULTS

An IBS patient's response or nonresponse to FMT was not determined by age, IBS duration, IBS subtype, IBS symptoms, fatigue, quality of life, or DI. There were more male nonresponders than responders, and the fluorescence signals of Alistipes were lower in nonresponders than in responders.

CONCLUSIONS

We concluded that IBS patients who are male and/or have low fecal Alistipes levels are most likely to not respond to FMT treatment. Whether low fecal Alistipes levels could be used as a marker for predicting the outcome of FMT remains to be determined. www.

CLINICALTRIALS

gov (NCT03822299).

The fecal microbiota transplantation response differs between patients with severe and moderate irritable bowel symptoms

OBJECTIVES

Fecal microbiota transplantation (FMT) is a promising intervention for patients with irritable bowel syndrome (IBS). The present study aimed to identify any differences in FMT response between patients with severe and moderate IBS symptoms.

MATERIALS AND METHOD

The study included the 164 patients who participated in our previous study, of which 96 (58.5%) and 68 (41.5%) had severe (S-IBS-S) and moderate (Mo-IBS-S) IBS, respectively. The patients were randomly divided into a placebo group (own feces) and 30-g and 60-g (donor feces) FMT groups. Patients completed three questionnaires that assessed their symptoms and quality of life at baseline and at 2 weeks, 1 month, and 3 months after FMT, and provided fecal samples before and 1 month after FMT. The fecal bacteria were analyzed using the 16S rRNA gene in PCR DNA amplification covering the V3-V9 variable genes.

RESULTS

Response rates of the placebo group did not differ between S-IBS-S and Mo-IBS-S patients at 2 weeks, 1 month and 3 months after FMT. The response rates in the active treatment group were higher in S-IBS-S patients than in Mo-IBS-S patients at each observation time. FMT reduced abdominal symptoms and fatigue and improved the quality of life in patients with both severe and moderate IBS. Patients with S-IBS-S had higher levels of Eubacterium siraeum, and lower levels of Eubacterium rectale than Mo-IBS-S, after FMT.

CONCLUSION

Patients with S-IBS-S have a higher response rate to FMT and a marked improvement in fatigue and in quality of life compared with those with Mo-IBS-S. The clinical trial registration number is NCT03822299 and is available at www.clinicaltrials.gov.

Fecal microbiota transplantation in the treatment of irritable bowel syndrome: a single-center prospective study in Japan

Background

Fecal microbiota transplantation (FMT) is a potential treatment for irritable bowel syndrome (IBS), but its efficacy in Japanese IBS patients is unknown. This study aimed to evaluate the efficacy, side effects, and microbiome changes following FMT in Japanese IBS patients.

Methods

Seventeen Japanese patients with refractory IBS received FMT (4 donors) under colonoscopy. Responders were defined by an improvement in the IBS severity index (IBS-SI) of 50 points or more after 12 weeks. We evaluated the IBS-SI and Bristol Stool Form Scale (BSFS) and compared the diversity and microbiome before and 12 weeks after FMT. For the microbiome, we analyzed the V3–V4 region of the 16S rRNA gene.

Results

IBS-SI decreased an average of 115.58 points after 12 weeks, and 10 patients (58.8%) were considered responders. Eight patients with diarrhea (66.7%) and three patients with constipation (60.0%) showed improvement in the BSFS. Two patients complained of mild abdominal pain, but there were no cases with severe side-effects. α-diversity was increased only in the responder group (p = 0.017). Patients who closely paralleled the donor microbiome had a higher rate of IBS-SI improvement. The relative abundance of Neisseria and Akkermansia increased and Desulfovibrio and Delftia were decreased in the responder group after FMT.

Conclusions

Following FMT, about 60% of Japanese patients with IBS showed improvement in both the IBS-SI and BSFS, without severe side effects. Increased α-diversity and similarity to the donor microbiome after FMT may be associated with better treatment effects.

Trial registration: This study was registered in the University Hospital Medical Information Network Clinical Trial Registration (UMIN000026363). Registered 31 May 2017, https://rctportal.niph.go.jp/s/detail/um?trial_id=UMIN000026363. The study was registered prospectively.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02408-5.

The Impact of Zinc and Zinc Homeostasis on the Intestinal Mucosal Barrier and Intestinal Diseases

Zinc is an essential trace element for living organisms, and zinc homeostasis is essential for the maintenance of the normal physiological functions of cells and organisms. The intestine is the main location for zinc absorption and excretion, while zinc and zinc homeostasis is also of great significance to the structure and function of the intestinal mucosal barrier. Zinc excess or deficiency and zinc homeostatic imbalance are all associated with many intestinal diseases, such as IBD (inflammatory bowel disease), IBS (irritable bowel syndrome), and CRC (colorectal cancer). In this review, we describe the role of zinc and zinc homeostasis in the intestinal mucosal barrier and the relevance of zinc homeostasis to gastrointestinal diseases.

Clinical translation of advanced colonic drug delivery technologies

Targeted drug delivery to the colon offers a myriad of benefits, including treatment of local diseases, direct access to unique therapeutic targets and the potential for increasing systemic drug bioavailability and efficacy. Although a range of traditional colonic delivery technologies are available, these systems exhibit inconsistent drug release due to physiological variability between and within individuals, which may be further exacerbated by underlying disease states. In recent years, significant translational and commercial advances have been made with the introduction of new technologies that incorporate independent multi-stimuli release mechanisms (pH and/or microbiota-dependent release). Harnessing these advanced technologies offers new possibilities for drug delivery via the colon, including the delivery of biopharmaceuticals, vaccines, nutrients, and microbiome therapeutics for the treatment of both local and systemic diseases. This review details the latest advances in colonic drug delivery, with an emphasis on emerging therapeutic opportunities and clinical technology translation.

Experimental and Computational Studies of Peristaltic Flow in a Duodenal Model

We study peristaltic flow in a C-shaped compliant tube representing the first section of the small intestine—the duodenum. A benchtop model comprising of a silicone tube filled with a glycerol-water mixture deformed by a rotating roller was created. Particle image velocimetry (PIV) was used to image flow patterns for deformations approximating conditions in the duodenum (contraction amplitude of 34% and wave speed 13 mm/s). Reversed flow was present underneath the roller with fluid moving opposite to the direction of the peristaltic wave propagation. Deformations of the tube were imaged and used to construct a computational fluid dynamics (CFD) model of flow with moving boundaries. The PIV and CFD vorticity and velocity fields were qualitatively similar. The vorticity field was integrated over the imaging region to compute the total circulation and there was on average a 22% difference in the total circulation between the experimental and numerical results. Higher shear rates were observed with water compared to the higher viscosity fluids. This model is a useful tool to study the effect of digesta properties, anatomical variations, and peristaltic contraction patterns on mixing and transport in the duodenum in health and disease.

Gluten-free Diet Reduces the Risk of Irritable Bowel Syndrome: A Mendelian Randomization Analysis

Background: Whether a gluten-free diet (GFD) is a cause of irritable bowel syndrome (IBS) remains controversial. We aim at exploring the causal relationship between gluten intake and IBS within Mendelian randomization (MR) design. Methods: We conducted a two-sample MR and selected single-nucleotide polymorphisms (SNPs) associated with GFD as instrumental variables (IVs). SNPs and genetic associations with GFD and IBS were obtained from the latest genome-wide association studies (GWAS) in Europeans (GFD: cases: 1,376; controls: 63,573; IBS: cases:1,121; controls: 360,073). We performed inverse variance weighting (IVW) as the primary method with several sensitivity analyses like MR-Egger and MR-PRESSO for quality control. The above analyses were re-run using another large dataset of IBS, as well as changing the p-value threshold when screening IVs, to verify the stability of the results. Results: The final estimate indicated significant causal association [per one copy of effect allele predicted log odds ratio (OR) change in GFD intake: OR = 0.97, 95% confidence interval (CI) 0.96 to 0.99, p < 0.01] without heterogeneity statistically (Q = 2.48, p = 0.78) nor horizontal pleiotropy biasing the causality (p = 0.92). Consistent results were found in validation analyses. Results of MR Steiger directionality test indicated the accuracy of our estimate of the causal direction (Steiger p < 0.001). Conclusion: GFD might be a protective factor of IBS. Therefore, we suggest taking a diet of lower gluten intake into account in IBS prevention and clinical practice.

Current status of fecal microbiota transplantation for irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common gastrointestinal functional disorder. Although IBS is a benign condition, it reduces the quality of life considerably. While there is currently no effective treatment for this disorder, fecal microbiota transplantation (FMT) seems to be promising.

PURPOSE

The aim of this review was to analysis possible factors affecting the success or failure of the randomized controlled trials (RCTs) of FMT for IBS and highlighting the gaps in our knowledge that need to be filled and of sketching a possible model for successful FMT in IBS patients.

METHODS

A systematic search was conducted of literature published in English from January 2015 to December 2020 using the keywords: fecal microbiota transplantation, randomized trials, and IBS.

KEY RESULTS

Seven randomized controlled trials (RCTs) on the efficacy of FMT for IBS were found in the literature. Four of the seven RCTs found various positive effects, while the other three did not find any effect.

CONCLUSIONS AND INFERENCES

The efficacy of FMT for IBS appears to be donor-dependent. The effective (super) donor would need to have a favorable microbiota signature, and 11 clinical criteria that are known to be associated with a favorable microbiota have been suggested for selecting FMT donors for IBS. Comparing the microbiota of the effective donors with those of healthy subjects would reveal the favorable microbiota signature required for a super-donor. However, the studies reviewed were not designed to compare efficacy of different donor types. The dose of the fecal transplant is also an important factor influencing the outcome of FMT for IBS. However, further studies designed to test the effect of fecal transplant dose are needed to answer this question. Administering the fecal transplant to either the small or large intestine seems to be effective, but the optimal route of administration remains to be determined. Moreover, whether single or repeated FMT is more effective is also still unclear. A 1-year follow-up of IBS patients who received FMT showed that adverse events of abdominal pain, diarrhea, and constipation were both mild and self-limiting.

Obesity and functional bowel disorders: are they linked?

Obesity and functional bowel disease (FBD) are affecting a large number of people worldwide. They have psychosocial consequences and associated with considerable healthcare resource use. The purpose of this review was a comprehensive study of the relationship between obesity and FBD, as well as mechanisms to explain this relationship. An analysis of the literature provides strong evidence of a link between obesity and diarrhea, but there is currently insufficient data to speak confidently about the link between obesity and irritable bowel syndrome. Most studies suggest that adult obesity is not associated or negatively associated with constipation. The association of obesity with diarrhea is most convincingly explained through diet, eating behavior, changes in the metabolism of bile acids, accelerated colonic transit, altered intestinal microbiota and associated inflammation and increased intestinal permeability. Medicines taken by patients, as well as non-alcoholic fatty liver disease, can play their own role.

Planning and conducting studies, including longitudinal ones, based on valid diagnostic criteria and taking into account the widest possible range of confounders, will allow a deeper study of the problem of comorbidity of obesity and FBD. This will help optimize the treatment of these diseases.

Fecal microbiota transplantation for irritable bowel syndrome: An intervention for the 21st century

Irritable bowel syndrome (IBS) affects about 12% of the global population. Although IBS does not develop into a serious disease or increase mortality, it results in a considerable reduction in the quality of life. The etiology of IBS is not known, but the intestinal microbiota appears to play a pivotal role in its pathophysiology. There is no effective treatment for IBS, and so the applied treatments clinically focus on symptom relief. Fecal microbiota transplantation (FMT), an old Chinese treatment, has been applied to IBS patients in seven randomized controlled trials (RCTs). Positive effects on IBS symptoms in various degrees were obtained in four of these RCTs, while there was no effect in the remaining three. Across the seven RCTs there were marked differences in the selection processes for the donor and treated patients, the transplant dose, the route of administration, and the methods used to measure how the patients responded to FMT. The present frontier discusses these differences and proposes: (1) criteria for selecting an effective donor (superdonor); (2) selection criteria for patients that are suitable for FMT; (3) the optimal FMT dose; and (4) the route of transplant administration. FMT appears to be safe, with only mild, self-limiting side effects of abdominal pain, cramping, tenderness, diarrhea, and constipation. Although it is early to speculate about the mechanisms underlying the effects of FMT, the available data suggest that changes in the intestinal bacteria accompanied by changes in fermentation patterns and fermentation products (specifically short-chain fatty acids) play an important role in improving the IBS symptoms seen after FMT. FMT appears to be a promising treatment for IBS, but further studies are needed before it can be applied in everyday clinical practice.

Responses to faecal microbiota transplantation in female and male patients with irritable bowel syndrome

BACKGROUND

Faecal microbiota transplantation (FMT) seems to be a promising treatment for irritable bowel syndrome (IBS) patients. In Western countries (United States and Europe), there is a female predominance in IBS. A sex difference in the response to FMT has been reported recently in IBS patients.

AIM

To investigate whether there was a sex difference in the response to FMT in the IBS patients who were included in our previous randomized controlled trial of the efficacy of FMT.

METHODS

The study included 164 IBS patients who participated in our previous randomized controlled trial. These patients had moderate-to-severe IBS symptoms belonging to the IBS-D (diarrhoea-predominant), IBS-C (constipation-predominant) and IBS-M (mixed) subtypes, and had not responded to the National Institute for Health and Care Excellence (NICE)-modified diet. They belonged in three groups: placebo (own faeces), and active treated group (30-g or 60-g superdonor faeces). The patients completed the IBS severity scoring system (IBS-SSS), Fatigue Assessment Scale (FAS) and the IBS quality of life scale (IBS-QoL) questionnaires at the baseline and 2 wk, 1 mo and 3 mo after FMT. They also provided faecal samples at the baseline and 1 mo after FMT. The faecal bacteria profile and dysbiosis were determined using the 16S rRNA gene polymerase chain reaction DNA amplification covering V3-V9; probe labelling by single nucleotide extension and signal detection. The levels of short-chain fatty acids (SCFAs) were determined by gas chromatography and flame ionization.

RESULTS

There was no sex difference in the response to FMT either in the placebo group or active treated group. There was no difference between females and males in either the placebo group or actively treated groups in the total score on the IBS-SSS, FAS or IBS-QoL, in dysbiosis, or in the faecal bacteria or SCFA level. However, the response rate was significantly higher in females with diarrhoea-predominant (IBS-D) than that of males at 1 mo, and 3 mo after FMT. Moreover, IBS-SSS total score was significantly lower in female patients with IBS-D than that of male patients both 1 mo and 3 mo after FMT.

CONCLUSION

There was no sex difference in the response to FMT among IBS patients with moderate-to-severe symptoms who had previously not responded to NICE-modified diet. However, female patients with IBS-D respond better and have higher reduction of symptoms than males after FMT.

The Effects of Fecal Microbiota Transplantation on the Symptoms and the Duodenal Neurogenin 3, Musashi 1, and Enteroendocrine Cells in Patients With Diarrhea-Predominant Irritable Bowel Syndrome

Introduction

Interactions between the gut microbiota and enteroendocrine cells play important role in irritable bowel syndrome (IBS). Reduced stem cell densities and their differentiation into enteroendocrine cells may cause abnormal densities of the duodenal enteroendocrine cells in IBS patients.

Materials and Methods

We aimed to investigate the effects of fecal microbiota transplantation (FMT) on stem cell differentiation into enteroendocrine cells as detected by neurogenin 3, stem cells as detected by Musashi 1, and the enteroendocrine cells in the duodenum of IBS patients. The study included 16 IBS patients according to Rome III criteria. Four patients were excluded. The remaining patients (n = 12, four females and eight males) were divided according to the cause of IBS into post-infectious (n = 6) and idiopathic (n = 6) IBS. They completed the following questionnaires before and 3 weeks after FMT: IBS-Symptom Severity Scoring system (IBS-SSS) and IBS-Symptom Questionnaire (IBS-SQ). Feces donated by healthy relatives of the patients were transplanted via gastroscope. Biopsies were taken from the descending part of the duodenum at baseline and 3 weeks after FMT. They were immunostained for neurogenin 3, Musashi 1, and all types of duodenal enteroendocrine cells and quantified by computerized image analysis. Microbiota analyses of feces collected just before and 3 weeks after FMT were performed using GA-map™ Dysbiosis test (Genetic Analysis AS, Oslo, Norway).

Results

The total scores for IBS-SSS and IBS-SQ were significantly improved 3 weeks after receiving FMT, P = 0.0009 and <0.0001, respectively. The stem cell densities of neurogenin 3 increased significantly following FMT (P = 0.0006) but not for Musashi 1 (P = 0.42). The cell densities of chromogranin A, cholecystokinin, gastric inhibitory peptide, serotonin, and somatostatin, but not for secretin, have significantly changed in both IBS groups after 3 weeks from receiving FMT.

Conclusion

More than two-thirds of IBS patients experienced improvement in their symptoms parallel to changes in the enteroendocrine cells densities 3 weeks after FMT. The changes in the enteroendocrine cell densities do not appear to be caused by changes in the stem cells or their early progenitors rather by changes in the differentiation progeny as detected by neurogenin 3. The study was retrospectively registered at ClinicalTrials.gov (ID: NCT03333291).

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT03333291.

Psychological defense mechanisms and use of corporeal discourse: a comparison between patients with irritable bowel syndrome, medical personnel and healthy volunteers

OBJECTIVE

The aim of this study was to compare the use of psychological defense mechanisms and corporeal discourse among patients with irritable bowel syndrome (IBS), medical personnel and healthy volunteers.

METHODS

All participants completed an identical battery of questionnaires: a demographic questionnaire, the Corporeal Discourse Questionnaire, the Defense Style Questionnaire and a Visual Analogue Scale for situational anxiety and depression. Patients and medical personnel were recruited from the Rabin Medical Center, a tertiary university-affiliated hospital. Findings were analyzed according to the study variables and compared among the groups.

RESULTS

Questionnaires were completed by 40 patients with IBS, 39 medical personnel and 40 healthy volunteers. Correlations between the study variables within the entire study group (all study participants, N = 119) revealed that corporeal discourse was found to be significantly correlated with the immature and neurotic class of defense mechanisms (r = 0.41, P < 0.01 and r = 0.20, P < 0.05, respectively), depression (r = 0.46, P < 0.05) and anxiety (r = 0.46, P < 0.05). Differences between IBS and the other two groups were significant for corporeal discourse, depression, anxiety and use of immature defense mechanisms. Posthoc analyses showed that medical personnel differed from IBS patients in all of these measures. Healthy volunteers had an inconsistent pattern of differences from the other two groups.

CONCLUSION

Maturity level of defense mechanisms and the tendency to use corporeal discourse are expressed among IBS patients in a diverse and unique manner. These findings may indicate additional psychological mechanisms that could explain the use of somatic complaints in IBS and support the implementation of tailored psychological interventions.

The CCL28 levels are elevated in the serum of patients with irritable bowel syndrome and associated with the clinical symptoms

BACKGROUND

Inflammation and inflammatory mediators have been proposed to be key players in the pathobiology of Irritable bowel syndrome (IBS. The chemokine CCL28 plays a role in the trafficking of inflammatory cells into mucosal tissues. However, its levels in patients with IBS has not been yet elucidated.

METHOD

In this study, the levels of CCL28 were measured in the serum of 41 patients with IBS and 41 age- and gender-matched normal individuals using Elisa. Then, the receiver operating characteristic (ROC) curve was conducted to assess the diagnostic value of CCL28.

RESULTS

Our data showed that the levels of CCL28 are significantly elevated in patients with IBS compared to the control donors. Moreover, we observed that the level of CCL28 is associated with many clinical symptoms such as constipation, diarrhea, and abdominal pain. The area under the ROC curve was 0.71 (95% confidential interval, 0.598-0.823), the sensitivity and specificity of CCL28 for the diagnosis of IBS patients were 68.3% and 70.7%, respectively with a cut off of 278.9 ng/mL.

CONCLUSIONS

We demonstrated that CCL28 is elevated in patients with IBS and correlates with clinical findings, indicating that CCL28 might be an appropriate biomarker for the diagnosis of IBS; however, further studies are necessary.

The role of diet in the pathophysiology and management of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic gastrointestinal (GI) disorder that reportedly affects 5% to 20% of the world population. The etiology of IBS is not completely understood, but diet appears to play an important role in its pathophysiology. Asian diets differ considerably from those in Western countries, which might explain differences in the prevalence, sex, and clinical presentation seen between patients with IBS in Asian and Western countries. Dietary regimes such as a low-fermentable oligo-, di-, monosaccharides, and polyols (FODMAP) diet and the modified National Institute for Health and Care Excellence (NICE) diet improve both symptoms and the quality of life in a considerable proportion of IBS patients. It has been speculated that diet is a prebiotic for the intestinal microbiota and favors the growth of certain bacteria. These bacteria ferment the dietary components, and the products of fermentation act upon intestinal stem cells to influence their differentiation into enteroendocrine cells. The resulting low density of enteroendocrine cells accompanied by low levels of certain hormones gives rise to intestinal dysmotility, visceral hypersensitivity, and abnormal secretion. This hypothesis is supported by the finding that changing to a low-FODMAP diet restores the density of GI cells to the levels in healthy subjects. These changes in gut endocrine cells caused by low-FODMAP diet are also accompanied by improvements in symptoms and the quality of life.

NUTRITIONAL STATUS, QUALITY OF LIFE AND LIFE HABITS OF WOMEN WITH IRRITABLE BOWEL SYNDROME: A CASE-CONTROL STUDY

BACKGROUND

Irritable bowel syndrome is a functional and chronic gastrointestinal disorder that may cause abdominal pain and altered bowel habits, affecting the nutritional status and quality of life of its carriers. Its prevalence is high, affecting about 10% to 15% of the general population in developed countries, being more prevalent in women than in men in the proportion 2:1.

OBJECTIVE

The aim of our study was to compare the profile of body adiposity, life habits, and the quality of life of women with irritable bowel syndrome with a healthy control group.

METHODS

Case-control study on 70 women, 34 with irritable bowel syndrome and 36 healthy. We applied the "Irritable Bowel Syndrome Quality of Life Questionnaire"to assess quality of life. Body adiposity was assessed from body mass index, waist circumference, and waist-to-hip ratio. We investigated the self-reporting of gastrointestinal symptoms with food deemed as problematic for carriers of irritable bowel syndrome and the presence of typical comorbidities. Assessment of life habits included: practice of physical activities, alcoholism, smoking, daytime sleepiness, and exclusion of foods from the feeding routine. For statistical analysis we used the IBM SPSS program, with a significance level at 5%.

RESULTS

There was higher volume of central and general adiposity in the case group compared with the control group (P<0.05). Cases presented a higher chance of developing IBS-related comorbidities (P<0.05). About of 80% of patients with irritable bowel syndrome have excluded some food from the diet (P<0.01) and the total amount of troublesome foods varied from 7 to 21 (P<0.01). The case group featured worse quality of life compared with the control (P<0.05).

CONCLUSION

Compared to the control group, women with irritable bowel syndrome showed greater body adiposity, higher frequency of comorbidities, greater restriction on the consumption of problematic foods and worse quality of life.

Density of Musashi‑1‑positive stem cells in the stomach of patients with irritable bowel syndrome

Irritable bowel syndrome (IBS) affects ~12% of the global population. Although the etiology of IBS is not completely understood, several factors are known to serve a pivotal role in its pathophysiology, including genetic factors, diet, the intestinal microbiota, gastrointestinal endocrine cells and low‑grade inflammation. Musashi‑1 is expressed by stem cells and their early progeny, and is used as a stem cell marker. The low density of intestinal endocrine cells in patients with IBS is thought to be caused by decreased numbers of intestinal stem cells and their differentiation into enteroendocrine cells. The present study employed Musashi‑1 as a marker to detect stem cells in the stomach of 54 patients with IBS and 51 healthy subjects. The patients and controls underwent standard gastroscopy, and biopsy samples were taken from the corpus and antrum. Immunohistochemical staining of gastrin, somatostatin and Mushasi‑1 was carried out and semi‑quantified by computerized image analysis. The density (number of positive cells/mm2 epithelium) of gastrin‑positive cells in the controls and patients with IBS were 337.9±560 and 531.0±908 (median ± range; P<0.0001), respectively. For somatostatin‑positive cells, the density reached 364.4±526.0 in the healthy controls and 150.7±514.0 in patients with IBS (P<0.0001). The density of Musashi‑1‑positive cells was defined as the number of cells per gastric or pyloric gland neck. In the corpus, Musashi‑1‑positive cells density reached 3.0±7.0 in the corpus of the healthy controls and 3.8±7.7 in the patients with IBS. Moreover, the corresponding values in the antrum were 6.0±6.0 and 6.0±6.0, respectively. The Musashi‑1‑positive cell density did not differ significantly between the controls and patients with IBS in the corpus or antrum (P=0.4 and 0.3, respectively). These findings indicated that changes in the stomach endocrine cells observed in patients with IBS may not be explained by an abnormality in stem cells like those found in the small and large intestines of these patients.

Burnout, but not job strain, is associated with irritable bowel syndrome in working adults

OBJECTIVE

Although stress is an important component of irritable bowel syndrome (IBS) pathophysiology, the possibility that work-related stress is implicated in the pathophysiology of IBS has not been widely studied. This study aimed to examine whether job strain (a combination of high job demands and low control at work) and/or burnout, the outcome of a gradual depletion of energetic resources resulting from chronic exposure to work-related stress, are associated with IBS.

METHODS

Fifty-five patients fulfilling the Rome III criteria for IBS and 214 matched healthy controls (HC) participated in this cross-sectional study. All participants completed a job strain measure, the Shirom - Melamed Burnout Measure (SMBM), and dietary and health questionnaires.

RESULTS

There was no significant difference in the prevalence of job strain between IBS patients and HC (25.5% vs. 23.0%, respectively). Job strain was not associated with increased IBS prevalence (adjusted OR = 1.99, 95% CI: 0.54-7.33). In contrast, the mean burnout score in the IBS group was significantly higher than in HC (2.9 ± 1.1 vs. 2.1 ± 0.8, p < .001). Burnout was associated with a 2.41-fold elevated prevalence of IBS (95% CI: 1.16-5.02), after adjusting for potential confounding variables including job strain. Moreover, the odds of having IBS increased in patients with a high burnout level (adjusted OR = 3.3, 95% CI:1.09-10.03).

CONCLUSION

Burnout, but not job strain, is associated with the prevalence of IBS in working adults.

Irritable bowel syndrome increases the risk of chronic obstructive pulmonary disease: A retrospective cohort study

Both inflammation and infection are associated with the development of irritable bowel syndrome (IBS) and chronic obstructive pulmonary disease (COPD). The purpose of this study is to further elucidate the association between IBS and COPD through a retrospective cohort study. We enrolled IBS patients diagnosed between 2000 and 2011 with follow-up for at least one year. The non-IBS patients as comparison group were selected with 1:3 matching by propensity score. Statistical analysis was utilized to assess the differences in characteristic distribution, and to compare the cumulative incidence of COPD between the IBS and non-IBS cohorts. We selected 14,021 IBS patients and 42,068 non-IBS patients for comparison. The IBS patients exhibited a significant risk to develop COPD compared with non-IBS patients. Additionally, the cumulative incidence rate of COPD in the IBS cohort increased significantly during the follow-up period of more than ten years, compared to the non-IBS cohort, based on the Kaplan-Meier analysis. The risk of COPD was also significantly decreased in those patients with more than eighteen IBS-related clinical visits. This retrospective cohort study demonstrates the significantly increased risk of COPD in patients with IBS. Therefore, early inspection and prevention of COPD is essential for patients with IBS.

The antibacterial activity of Berberis heteropoda Schrenk and its effect on irritable bowel syndrome in rats

The dried roots of Berberis heteropoda Schrenk have traditionally been used to treat acute gastroenteritis and dysentery. The aim of this study was to confirm the antibacterial activity of an extract of Berberis heteropoda Schrenk rootin vitro and its therapeutic effects on rats with diarrhea-predominant irritable bowel syndrome (D-IBS) in vivo, as well as to identify the related signaling pathways. A water extract of Berberis heteropoda Schrenk root (BHS) inhibited the growth of S. aureus, E. coli, P. aeruginosa and S. faecalis. BHS potentially damaged the structure of the bacterial cell membrane and decreased the activity of some membranous enzymes, eventually killing the S. aureus, E. coli, P. aeruginosa and S. faecalis bacteria. Oral administration of BHS (low, middle and high dose group, L, M and H) significantly alleviated the abdominal pain, diarrhea, and depression-like symptoms of D-IBS rats, and the efficacy index ranged from 30% to 60%, indicating that the BHS treatment was effective. BHS (L, M and H) alleviated the abnormal pathological changes in the brain, as evidenced by HE staining. The expression of CHAT, 5-HT, C-FOS and CGRP was reduced by the BHS treatment (L, M and H). Our findings provide novel insights into the use of the natural product BHS to inhibit pathogenic bacteria by destroying the bacterial structure, indicating that BHS possesses certain biological activities. Furthermore, BHS has the potential to alleviate diarrhea, abdominal pain and depression-like behaviors in D-IBS rats by regulating the brain-gut peptide levels.

Possible role of intestinal stem cells in the pathophysiology of irritable bowel syndrome

The pathophysiology of irritable bowel syndrome (IBS) is not completely understood. However, several factors are known to play a role in pathophysiology of IBS such as genetics, diet, gut microbiota, gut endocrine cells, stress and low-grade inflammation. Understanding the pathophysiology of IBS may open the way for new treatment approaches. Low density of intestinal stem cells and low differentiation toward enteroendocrine cells has been reported recently in patients with IBS. These abnormalities are believed to be the cause of the low density of enteroendocrine cells seen in patients with IBS. Enteroendocrine cells regulate gastrointestinal motility, secretion, absorption and visceral sensitivity. Gastrointestinal dysmotility, abnormal absorption/secretion and visceral hypersensitivity are all seen in patients with IBS and haven been attributed to the low density the intestinal enteroendocrine cells in these patients. The present review conducted a literature search in Medline (PubMed) covering the last ten years until November 2019, where articles in English were included. Articles about the intestinal stem cells and their possible role in the pathophysiology of IBS are discussed in the present review. The present review discusses the assumption that intestinal stem cells play a central role in the pathophysiology of IBS and that the other factors known to contribute to the pathophysiology of IBS such as genetics, diet gut microbiota, stress, and low-grade inflammation exert their effects through affecting the intestinal stem cells. It reports further the data that support this assumption on genetics, diet, gut microbiota, stress with depletion of glutamine, and inflammation.

Possible role of peptide YY (PYY) in the pathophysiology of irritable bowel syndrome (IBS)

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder of unknown aetiology for which there is no effective treatment. Although IBS does not increase mortality, it reduces the quality of life and is an economic burden to both the patients themselves and society as a whole. Peptide YY (PYY) is localized in endocrine cells located in the ileum, colon and rectum. The concentration of PYY and the density of PYY cells are decreased in both the colon and rectum but unchanged in the ileum of patients with IBS. The low density of PYY cells in the large intestine may be caused by a decreased number of stem cells and their progeny toward endocrine cells. PYY regulates the intestinal motility, secretion and absorption as well as visceral sensitivity via modulating serotonin release. An abnormality in PYY may therefore contribute to the intestinal dysmotility and visceral hypersensitivity seen in IBS patients. Diet management involving consuming a low-FODMAP diet restores the density of PYY cells in the large intestine and improves abdominal symptoms in patients with IBS. This review shows that diet management appears to be a valuable tool for correcting the PYY abnormalities in the large intestine of IBS patients in the clinic.

Randomised, double-blind, placebo controlled multi-centre study to assess the efficacy, tolerability and safety of Enterosgel® in the treatment of irritable bowel syndrome with diarrhoea (IBS-D) in adults

BACKGROUND

Irritable bowel syndrome (IBS) with diarrhoea (IBS-D) is a common and chronic condition that can significantly impair quality of life. The emergence of new drugs for IBS-D has been slow and there is a need for new treatments, including drug-free treatments, which are easy to use and suitable for different patient groups. Currently available drug-free treatments include Enterosgel®, an intestinal adsorbent approved for use in IBS-D and acute diarrhoea and available over-the-counter in the UK and 30 countries worldwide. The aim of this randomised, double-blind, placebo-controlled, multi-centre study is to test the efficacy and safety of Enterosgel® compared to placebo in symptomatic treatment in IBS-D.

METHODS/DESIGN

We will recruit 430 participants with IBS-D from approximately 30 primary and secondary care sites in England. Participants meeting the required abdominal pain and stool consistency criteria over a 2-week screening period will be randomly allocated to receive blinded treatment (Enterosgel® or placebo) for 8 weeks. This will be followed by an 8-week open-label treatment phase with Enterosgel®. Participants will be allowed to adjust their daily dosage during both phases based on their symptoms. Participants will then return to standard care and those who responded to treatment will receive a follow-up call 8 weeks later. Co-medication with loperamide will be permitted and use recorded. The primary outcome measure is the percentage of participants defined as responders for abdominal pain and stool consistency during at least 4 weeks in the 8-week blinded phase. Secondary outcome measures include stool frequency, stool consistency, abdominal pain, bloating, urgency, adequate relief, questionnaire scores and rescue medication use. Exploratory outcomes will be assessed in subsets of participants including qualitative and quantitative data on faecal microorganisms and biomarkers and gut-related measurements from magnetic resonance imaging data.

DISCUSSION

This is the first large scale randomised controlled trial investigating Enterosgel® in IBS-D. A study design with blinded phase followed by an open-label phase was chosen to encourage participation and study completion. Demonstrating that Enterosgel® is effective and safe in IBS-D could encourage adoption by patients and healthcare professionals and foster future clinical trials assessing its use in related conditions.

TRIAL REGISTRATION

ISRCTN17149988. Prospectively registered on 14 November 2017.

The Role of Transient Receptor Potential Vanilloid 1 in Common Diseases of the Digestive Tract and the Cardiovascular and Respiratory System

Transient receptor potential vanilloid subtype 1 (TRPV1), a member of the transient receptor potential vanilloid (TRPV) channel family, is a nonselective cation channel that is widely expressed in sensory nerve fibers and nonneuronal cells, including certain vascular endothelial cells and smooth muscle cells. The activation of TRPV1 may be involved in the regulation of various physiological functions, such as the release of inflammatory mediators in the body, gastrointestinal motility function, and temperature regulation. In recent years, a large number of studies have revealed that TRPV1 plays an important role in the physiological and pathological conditions of the digestive system, cardiovascular system, and respiratory system, but there is no systematic report on TRPV1. The objective of this review is to explain the function and effects of TRPV1 on specific diseases, such as irritable bowel syndrome, hypertension, and asthma, and to further investigate the intrinsic relationship between the expression and function of TRPV1 in those diseases to find new therapeutic targets for the cure of related diseases.

Diet in Irritable Bowel Syndrome (IBS): Interaction with Gut Microbiota and Gut Hormones

Diet plays an important role not only in the pathophysiology of irritable bowel syndrome (IBS), but also as a tool that improves symptoms and quality of life. The effects of diet seem to be a result of an interaction with the gut bacteria and the gut endocrine cells. The density of gut endocrine cells is low in IBS patients, and it is believed that this abnormality is the direct cause of the symptoms seen in IBS patients. The low density of gut endocrine cells is probably caused by a low number of stem cells and low differentiation progeny toward endocrine cells. A low fermentable oligo-, di-, monosaccharide, and polyol (FODMAP) diet and fecal microbiota transplantation (FMT) restore the gut endocrine cells to the level of healthy subjects. It has been suggested that our diet acts as a prebiotic that favors the growth of a certain types of bacteria. Diet also acts as a substrate for gut bacteria fermentation, which results in several by-products. These by-products might act on the stem cells in such a way that the gut stem cells decrease, and consequently, endocrine cell numbers decrease. Changing to a low-FODMAP diet or changing the gut bacteria through FMT improves IBS symptoms and restores the density of endocrine cells.

Increasing the Dose and/or Repeating Faecal Microbiota Transplantation (FMT) Increases the Response in Patients with Irritable Bowel Syndrome (IBS)

BACKGROUND

Faecal microbiome transplantation (FMT) appears to be an effective method for treating irritable bowel syndrome (IBS) patients. However, it is not clear if a high transplant dose and/or repeating FMT are/is needed to ensure a response. The present study was undertaken to clarify this matter.

METHODS

Ten IBS patients who did not respond to a 30-g transplant subsequently received a 60-g transplant into the duodenum via a gastroscope. The patients provided faecal samples before and 1 month after FMT. They completed five questionnaires measuring symptoms, fatigue and quality of life at baseline and then at 2 weeks, 1 month and 3 months after FMT. The dysbiosis index (DI) was measured using the GA-map Dysbiosis Test®.

RESULTS

Seven patients (70%) responded to the 60-g transplant, with significant clinical improvements in the abdominal symptoms, fatigue and quality of life in 57%, 80% and 67% of these patients. The 60-g transplant also reduced the DI.

CONCLUSION

FMT is an effective treatment for IBS. A high-dose transplant and/or repeated FMT increase the response rate and the intensity of the effects of FMT.

Proton pump inhibitors and dysbiosis: Current knowledge and aspects to be clarified

Proton pump inhibitors (PPIs) are common medications within the practice of gastroenterology. These drugs, which act through the irreversible inhibition of the hydrogen/potassium pump (H+/K+-ATPase pump) in the gastric parietal cells, are used in the treatment of several acid-related disorders. PPIs are generally well tolerated but, through the long-term reduction of gastric acid secretion, can increase the risk of an imbalance in gut microbiota composition (i.e., dysbiosis). The gut microbiota is a complex ecosystem in which microbes coexist and interact with the human host. Indeed, the resident gut bacteria are needed for multiple vital functions, such as nutrient and drug metabolism, the production of energy, defense against pathogens, the modulation of the immune system and support of the integrity of the gut mucosal barrier. The bacteria are collected in communities that vary in density and composition within each segment of the gastrointestinal (GI) tract. Therefore, every change in the gut ecosystem has been connected to an increased susceptibility or exacerbation of various GI disorders. The aim of this review is to summarize the recently available data on PPI-related microbiota alterations in each segment of the GI tract and to analyze the possible involvement of PPIs in the pathogenesis of several specific GI diseases.

How Patients with IBS Use Low FODMAP Dietary Information Provided by General Practitioners and Gastroenterologists: A Qualitative Study

There is a lack of dietitians trained to deliver the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet (LFD) for irritable bowel syndrome (IBS). Many patients receive nutritional information from general practitioners (GPs) or gastroenterologists (GEs). Since the LFD is dietitian-led, the aim of this research was to qualitatively explore the effects of GP- and GE-delivered LFD information, in IBS self-management. Semi-structured interviews were conducted in a purposive sample of 8 people with IBS (6 female), who used the LFD as their primary treatment. Interpretive Phenomenological Analysis (IPA) was used to develop themes on the lived experience of the participant’s use of LFD information from GPs and GEs. This information was perceived as trustworthy but simplistic; often just ”food lists” with little personalisation to meet individual needs and difficult to apply in ”real life”. The information required substantial interpretation and the familial and social effects of implementation were not addressed in the materials provided. Supplementary digital resources were regarded as more practical but the participants expressed concern in relation to the validity of these materials. The findings in this study support current clinical guidelines proposed by both the National Institute for Health and Care Excellence and the British Dietetic Association that the LFD should be considered a dietitian-led only intervention.

Overlapping of irritable bowel syndrome with erosive esophagitis and the performance of Rome criteria in diagnosing IBS in a clinical setting

Irritable bowel syndrome (IBS) and gastroesophageal reflux disease (GERD) overlap. It is not clear whether GERD is caused by non-erosive esophagitis, or erosive esophagitis. The Rome criteria are not widely used for the diagnosis of IBS in the clinic. In total, 1,489 IBS patients without red flags were included in the present retrospective study. They comprised of 1,331 females and 158 males with a mean age of 51 years. The diagnosis of IBS was verified by endoscopic and histopathological examinations. Whereas erosive esophagitis occurred in 97% of patients, only 66% had GERD symptoms. Endoscopy and histopathological examinations revealed that 1.4% of the IBS patients with diarrhea as the predominant symptom had other organic gastrointestinal diseases: 0.3% with celiac disease, 0.2% with Crohn's disease, 0.07% with ulcerative colitis, 0.6% with microscopic colitis, and 0.2% with colon cancer. Applying the Rome III criteria produced a sensitivity of 100% [95% confidence intervals (CI)=99.8–100.0%] a specificity of 98.7% (95% CI=98.0–99.2%), a positive likelihood ratio of 76.9%, and a negative likelihood ratio of 0%. IBS is associated with erosive esophagitis. Applying Rome III criteria without red flags and history, was effective in diagnosing IBS. Celiac disease and microscopic colitis should be considered as alternative diagnoses.

[One or more functional somatic syndromes? Comparison of the health status of fibromyalgia and electro-hypersensitive people]

INTRODUCTION

Functional somatic syndromes, grouping somatic symptoms without an organic explanation, are defined either by their predominant symptoms or by an attribution to an, often hypothetical, cause. Due to many similarities, some authors consider that there is only one FSS due to a general phenomenon of "somatization". The objective of this work was to compare two functional somatic syndromes, one defined by its symptoms, fibromyalgia, and the other by a specific contested attribution, electro-hypersensitivity.

METHOD

Fibromyalgia or electro-hypersensitive participants (EHS) were recruited from September 2016 to April 2017 through associations of patients in Auvergne-Rhône-Alpes. Home interviews included the collection of medical, psychopathological, and symptom histories. The assessment of psychological distress, quality of life and the search for other functional somatic syndromes was performed through structured questionnaires, self-administrated scales, and clinical examination.

RESULTS

Sixteen fibromyalgia subjects and sixteen EHS subjects were included. There are differences in symptomatology, although many symptoms are common to both conditions. Lifetime history of psychiatric disorders and current psychological distress and psychopathology are frequent in both groups but more prevalent in fibromyalgia subjects. The experience of the symptoms, their interpretation, the diagnostic itineraries and the therapeutic behaviours differ radically according to the group, even if for all socio-professional impact is high and quality of life are altered.

CONCLUSION

The health status of fibromyalgia persons is overall worse than the health status of electro-hypersensitive individuals in this small sample. Despite the overlap in symptoms and a similar impact on daily functioning, this exploratory study suggests that heterogeneous mechanisms of "somatization" may be at stake in functional somatic syndromes.

Adherence with a low-FODMAP diet in irritable bowel syndrome: are eating disorders the missing link?

OBJECTIVES

The low-FODMAP diet has emerged as an option for the treatment of irritable bowel syndrome (IBS). This diet is very restrictive, and compliance is usually low. Preliminary findings suggest an association between eating disorders (EDs) and the risk of developing IBS. The aim of this study was to assess the correlation between compliance with a low-FODMAP diet and the risk of ED behaviours among patients with IBS.

PATIENTS AND METHODS

A single-centre prospective study was carried out among 233 IBS patients (79.8% females) at University College London Hospital, who commenced a low FODMAPs group programme for IBS (Rome III or IV). Self-reported diet adherence at the end of the 6-week programme was measured. At baseline, and at the 6-week follow-up visit, participants completed the validated IBS-Symptom Severity Score, the SCOFF ED screening questionnaire and the Hospital Anxiety and Depression Scale.

RESULTS

Adherence with a low-FODMAP diet was found in 95 (41%) patients. Overall, 54 (23%) patients were classified to be at risk for ED behaviour. Adherence was 57% in the ED group (31/54) versus 35% in the non-ED group (64/179); P<0.05. Adherence with a low-FODMAP diet was highest (51%) in the IBS with diarrhoea subtype and lowest (10%) in IBS with constipation. There was no significant correlation between IBS-Symptom Severity Score and either adherence (P=0.39) or ED behaviour (P=0.28).

CONCLUSION

In this IBS cohort, greater adherence to a low-FODMAP diet is associated with ED behaviour. The implications of our study are important in clinical practice for a clinician to have a high index of suspicion of EDs in IBS patients when a high level of low-FODMAP diet achieved.

Stress-strain analysis of duodenal contractility in response to flow and ramp distension in rabbits fed low-fiber diet

BACKGROUND

Previously we demonstrated that low-fiber diet in rabbits affects the passive mechanomorphological properties in the small intestine, resulting in reduced intestinal wall thickness and collagen content, as well as intestinal wall softening. The aim of the present study was to evaluate the contractility in rabbits on long-term low-fiber diet and specifically to compare the contraction threshold, the frequency, and the amplitude of flow-induced and distension-induced contractions in the duodenum between rabbits on normal diet and on long-term low-fiber diet.

METHODS

Ten rabbits were fed a low-fiber diet for 5 months (Intervention group), and five rabbits were fed normal diet (Control group). The duodenal segments were used for determination of mechanical parameters for analyses of contractility. The duodenal experiments were carried out in organ baths containing physiological Krebs solution. Pressure and diameter changes induced by contractions in response to flow and ramp distension were measured. The frequencies and amplitude of contractions were analyzed. Distension-induced contraction thresholds and maximum contraction amplitude of flow-induced contractions were calculated in terms of mechanical stress and strain. Multiple linear regression analyses were applied to study dependencies between contractility parameters and wall thickness, wall area, and muscle layer thickness.

KEY RESULTS

During distension, the pressure, stress, and strain thresholds for induction of phasic contraction were biggest in the Intervention Group (P < 0.05). In addition, the contraction frequencies during flow-induced contraction were highest in the Intervention Group (P < 0.05), whereas the maximum contraction amplitudes in terms of pressure, diameter, stress, and strain were lowest in the Intervention Group (P < 0.05). The contraction thresholds and contraction frequencies were negatively associated with the wall thickness, wall area, and muscle layer thickness, whereas maximum contraction amplitudes were positively associated with the wall thickness, wall area, and muscle layer thickness.

CONCLUSIONS AND INFERENCES

Duodenal contractility in rabbits fed with long-term low-fiber diet exhibited low contraction amplitudes and high contraction thresholds and frequencies. The changes were associated with the low-fiber diet-induced histomorphological remodeling. Studies on detailed structural and functional diet-induced changes in smooth muscle and intestinal nerves are needed for better understanding the remodeling mechanisms.

Association of the Vitamin D Level and Quality of School Life in Adolescents with Irritable Bowel Syndrome

There is no treatment of choice for irritable bowel syndrome, which affects up to 20% of school-aged children. This cross-sectional study evaluated the difference in the average vitamin D level between subtypes of irritable bowel syndrome, and the relationship between the vitamin D level as well as the severity of irritable bowel syndrome symptoms. We included 124 adolescents aged 10–17 years (68 boys, 56 girls; mean age 12.29 ± 1.92 years) from 2014 to 2016. Patients with irritable bowel syndrome were diagnosed by Rome III criteria and classified by clinical manifestation: irritable bowel syndrome with constipation (n = 29), irritable bowel syndrome with diarrhea (n = 63), and irritable bowel syndrome with constipation and diarrhea (n = 32). The severity of irritable bowel syndrome symptoms and school absence were evaluated. Vitamin D levels were measured by serum 25-hydroxyvitamin D. The chi-square test and analysis of variance were used. The patients’ average vitamin D level was 16.25 ± 6.58 ng/mL. There was a significant negative association of the 25-hydroxyvitamin D level with symptom severity and school absence (p = 0.022 and p < 0.001, respectively). Vitamin D supplementation could be considered as a choice of therapeutic method.

Local delivery of macromolecules to treat diseases associated with the colon

Current treatments for intestinal diseases including inflammatory bowel diseases, irritable bowel syndrome, and colonic bacterial infections are typically small molecule oral dosage forms designed for systemic delivery. The intestinal permeability hurdle to achieve systemic delivery from oral formulations of macromolecules is challenging, but this drawback can be advantageous if an intestinal region is associated with the disease. There are some promising formulation approaches to release peptides, proteins, antibodies, antisense oligonucleotides, RNA, and probiotics in the colon to enable local delivery and efficacy. We briefly review colonic physiology in relation to the main colon-associated diseases (inflammatory bowel disease, irritable bowel syndrome, infection, and colorectal cancer), along with the impact of colon physiology on dosage form design of macromolecules. We then assess formulation strategies designed to achieve colonic delivery of small molecules and concluded that they can also be applied some extent to macromolecules. We describe examples of formulation strategies in preclinical research aimed at colonic delivery of macromolecules to achieve high local concentration in the lumen, epithelial-, or sub-epithelial tissue, depending on the target, but with the benefit of reduced systemic exposure and toxicity. Finally, the industrial challenges in developing macromolecule formulations for colon-associated diseases are presented, along with a framework for selecting appropriate delivery technologies.

Aluminum Ingestion Promotes Colorectal Hypersensitivity in Rodents

Background & Aims

Irritable bowel syndrome (IBS) is a multifactorial disease arising from a complex interplay between genetic predisposition and environmental influences. To date, environmental triggers are not well known. Aluminum is commonly present in food, notably by its use as food additive. We investigated the effects of aluminum ingestion in rodent models of visceral hypersensitivity, and the mechanisms involved.

Methods

Visceral hypersensitivity was recorded by colorectal distension in rats administered with oral low doses of aluminum. Inflammation was analyzed in the colon of aluminum-treated rats by quantitative PCR for cytokine expression and by immunohistochemistry for immune cells quantification. Involvement of mast cells in the aluminum-induced hypersensitivity was determined by cromoglycate administration of rats and in mast cell-deficient mice (KitW-sh/W-sh). Proteinase-activated receptor-2 (PAR2) activation in response to aluminum was evaluated and its implication in aluminum-induced hypersensitivity was assessed in PAR2 knockout mice.

Results

Orally administered low-dose aluminum induced visceral hypersensitivity in rats and mice. Visceral pain induced by aluminum persisted over time even after cessation of treatment, reappeared and was amplified when treatment resumed. As observed in humans, female animals were more sensitive than males. Major mediators of nociception were up-regulated in the colon by aluminum. Activation of mast cells and PAR2 were required for aluminum-induced hypersensitivity.

Conclusions

These findings indicate that oral exposure to aluminum at human dietary level reproduces clinical and molecular features of IBS, highlighting a new pathway of prevention and treatment of visceral pain in some susceptible patients.

Guidelines on the management of irritable bowel syndrome: In memory of Professor Witold Bartnik

These guidelines constitute an update of the previous "Recommendations on the management of irritable bowel syndrome" issued in 2008. They have been developed by a Task Force organized by the Governing Board of the Polish Society of Gastroenterology. They discuss, with particular emphasis on new scientific data covering papers published since 2008, the aetiology, epidemiology, clinical presentation, diagnostic principles and criteria for the diagnosis, and recommendations for the treatment of irritable bowel syndrome (IBS). The English-language acronym for the syndrome (IBS) has become popular in medical and popular scientific language. It is also widely recognized by patients who identify with this diagnosis. Therefore, in the discussed guidelines, this is what we will use.

Investigating the Effect of Mindfulness-Based Training on Psychological Status and Quality of Life in Patients with Breast Cancer

Cancer poses substantial challenges to both physical and mental health of patients. On the other hand, breast cancer is one of the most common cancers among Iranian women. Therefore, the present study was conducted to investigate the effect of mindfulness-based training on psychological status and quality of life (QoL) of patients with breast cancer living in Ilam, Iran. This quasi-experimental study was performed on 66 patients diagnosed with breast cancer. The patients assigned into two groups of experimental and control. Experimental group received mindfulness-based group training through eight 90-min sessions. Sessions were conducted twice a week and were completed within 1 month. The research tools included a QoL questionnaire (WHOQOL-BREF), Schneider’s life expectancy questionnaire, and the depression anxiety stress scale (DASS-21). The questionnaires were completed before and during the interviews with the patients 2 months after intervention. Data were analyzed using SPSS (version 16) and running descriptive and analytical statistics. Before the intervention, there was no significant difference between he experimental and control groups considering QoL, life expectancy, depression, anxiety, and stress (p>0.05). However, after the intervention, the patients in the experimental group reported higher QoL and life expectancy and less severe depression, anxiety, and stress (p < 0.05). Considering the positive effect of mindfulness-based training on the psychological status and QoL of patients with breast cancer, we recommend health nurses conduct mindfulness-based training for patients receiving clinical care services.

FABP4 blocker attenuates colonic hypomotility and modulates white adipose tissue-derived hormone levels in mouse models mimicking constipation-predominant IBS

BACKGROUND

The role of fatty acid binding protein 4 (FABP4) in lower gastrointestinal (GI) motility is unknown. We aimed to verify the effect of inhibition of FABP4 on GI transit in vivo, and to determine the expression of FABP4 in mouse and human tissues.

METHODS

Fatty acid binding protein 4 inhibitor, BMS309403, was administered acutely or chronically for 6 and 13 consecutive days and its effect on GI transit was assessed in physiological conditions and in loperamide-induced constipation. Intracellular recordings were made to examine the effects of BMS309403 on colonic excitatory and inhibitory junction potentials. Abdominal pain was evaluated using behavioral pain response. Localization and expression of selected adipokines were determined in the mouse colon and serum using immunohistochemistry and Enzyme-Linked ImmunoSorbent Assay respectively. mRNA expression of FABP4 and selected adipokines in colonic and serum samples from irritable bowel syndrome (IBS) patients and control group were assessed.

KEY RESULTS

Acute injection of BMS309403 significantly increased GI motility and reversed inhibitory effect of loperamide. BMS309403 did not change colonic membrane potentials. Chronic treatment with BMS309403 increased the number of pain-induced behaviors. In the mouse serum, level of resistin was significantly decreased after acute administration; no changes in adiponectin level were detected. In the human serum, level of adiponectin and resistin, but not of FABP4, were significantly elevated in patients with constipation-IBS (IBS-C). FABP4 mRNA expression was significantly downregulated in the human colon in IBS-C.

CONCLUSIONS AND INFERENCES

Fatty acid binding protein 4 may be involved in IBS pathogenesis and become a novel target in the treatment of constipation-related diseases.