Irritable bowel syndrome: modern concepts and management options

Gastrointestinal pathophysiology in long COVID: Exploring roles of microbiota dysbiosis and serotonin dysregulation in post-infectious bowel symptoms

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggered an unprecedented public health crisis known as the coronavirus disease 2019 (COVID-19) pandemic. Gastrointestinal (GI) symptoms develop in patients during acute infection and persist after recovery from airway distress in a chronic form of the disease (long COVID). A high incidence of irritable bowel syndrome (IBS) manifested by severe abdominal pain and defecation pattern changes is reported in COVID patients. Although COVID is primarily considered a respiratory disease, fecal shedding of SARS-CoV-2 antigens positively correlates with bowel symptoms. Active viral infection in the GI tract was identified by human intestinal organoid studies showing SARS-CoV-2 replication in gut epithelial cells. In this review, we highlight the key findings in post-COVID bowel symptoms and explore possible mechanisms underlying the pathophysiology of the illness. These mechanisms include mucosal inflammation, gut barrier dysfunction, and microbiota dysbiosis during viral infection. Viral shedding through the GI route may be the primary factor causing the alteration of the microbiome ecosystem, particularly the virome. Recent evidence in experimental models suggested that microbiome dysbiosis could be further aggravated by epithelial barrier damage and immune activation. Moreover, altered microbiota composition has been associated with dysregulated serotonin pathways, resulting in intestinal nerve hypersensitivity. These mechanisms may explain the development of post-infectious IBS-like symptoms in long COVID. Understanding how coronavirus infection affects gut pathophysiology, including microbiome changes, would benefit the therapeutic advancement for managing post-infectious bowel symptoms.

Evaluation of the effects of the FODMAP diet and probiotics on irritable bowel syndrome (IBS) symptoms, quality of life and depression in women with IBS

BACKGROUND

The present study aimed to evaluate the effects of fermented oligosaccharide, disaccharide, monosaccharide and polyols (FODMAP) diet therapy and probiotics on irritable bowel syndrome (IBS) symptoms, quality of life and depression in women diagnosed with IBS.

METHODS

For the study, 52 female IBS patients between the ages of 20 and 55 were enrolled. Individuals were monitored for 6 weeks in two groups. A low-FODMAP diet was given to the first group and a low-FODMAP diet plus a probiotic supplement was given to the second group (Lactobacillus rhamnosus). Three-day food intake records were kept at the start of the study and continued up to its conclusion, with a weekly check-in in between. At the start and end of the trial, participants completed the Hospital Anxiety and Depression Scale, IBS Quality of Life Scale (IBS-QOL) and IBS Symptom Severity Score (IBS-SSS). The Bristol Stool Scale was also used by the subjects to record their daily stool densities.

RESULTS

At the end of the study, it was determined that the daily intake of FODMAP (lactose [g] + oligosaccharides [g] + mannitol [g] + sorbitol [g]) decreased significantly in both groups (p < 0.05). At the end of the study, it was determined that the IBS-SSS, anxiety and depression scores of the individuals in both groups decreased significantly and their IBS-QOL scores increased significantly (p < 0.05). However, the difference between these values between the groups was not statistically significant (p > 0.05).

CONCLUSIONS

A low-FODMAP diet has been demonstrated to benefit people by lessening the severity of their IBS symptoms and enhancing their quality of life. No evidence was found, however, to indicate that the FODMAP diet would be more beneficial on these metrics if additional probiotics were used. It should be emphasised that the reaction of probiotic strains may vary depending on the IBS subtype.

The impact of gastrointestinal conditions on psychosocial factors associated with the biopsychosocial model of health: A scoping review

The increase in the prevalence of gastrointestinal (GI) conditions is an emerging global health concern. Studies of the impact on the lives of individuals living with GI conditions such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) typically focus on biological elements, such as symptomology and treatment efficacy. Comparatively fewer studies have explored the psychological and social aspects of GI conditions, which could provide key information needed to better understand the impact of GI conditions on people and their lived experiences. In this review, existing literature concerning the psychosocial factors and well-being outcomes associated with GI conditions was reviewed using a scoping methodology. Sixty-eight studies were selected for inclusion. Of these studies, the well-being outcomes most frequently addressed, for both IBS and IBD, were quality of life and health-related quality of life, and the most frequently addressed psychosocial factors were social support and coping. These outcomes are largely consistent with those identified for other medical conditions explored using the biopsychosocial model of health, with some exploration of the lived experiences of those with a GI condition.

Biomolecules from Plant Wastes Potentially Relevant in the Management of Irritable Bowel Syndrome and Co-Occurring Symptomatology

During and following the processing of a plant’s raw material, considerable amounts are wasted, composted, or redistributed in non-alimentary sectors for further use (for example, some forms of plant waste contribute to biofuel, bioethanol, or biomass production). However, many of these forms of waste still consist of critical bioactive compounds used in the food industry or medicine. Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders. The primary treatment is based on symptomatology alleviation and controlled dietary management. Thus, this review aimed to describe the possible relevance of molecules residing in plant waste that can be used to manage IBS and co-occurring symptoms. Significant evidence was found that many forms of fruit, vegetable, and medicinal plant waste could be the source of some molecules that could be used to treat or prevent stool consistency and frequency impairments and abdominal pain, these being the main IBS symptoms. While many of these molecules could be recovered from plant waste during or following primary processing, the studies suggested that enriched food could offer efficient valorization and prevent further changes in properties or stability. In this way, root, stem, straw, leaf, fruit, and vegetable pomaces were found to consist of biomolecules that could modulate intestinal permeability, pain perception, and overall gastrointestinal digestive processes.

A survey of gastroenterologists in the United States on the use of central neuromodulators for treating irritable bowel syndrome

BACKGROUND

Central neuromodulators are an effective treatment for irritable bowel syndrome (IBS) but may be used less frequently than other therapies.

AIMS

To survey gastroenterologists in the United States (US) about their use of neuromodulators in patients with IBS.

METHODS

A 23-question survey was distributed to gastroenterologists in the United States. Comparisons in prescribing practices were conducted between (a) gastroenterologists who were "high prescribers" versus "low prescribers" of neuromodulators in patients with IBS and (b) gastroenterologists and "gastroenterology experts" in the use of neuromodulators using descriptive statistics and multivariable logistic regression analyses.

RESULTS

The 525 gastroenterologists who were surveyed used neuromodulators for a median range of 21%-30% of their patients with IBS. Neuromodulators were described as extremely/very important in managing IBS by 55% of clinicians. Significant predictors of high-prescribing behaviour were academic versus clinical practice setting (odds ratio [OR] 2.60 [95% CI 1.61-4.20]), disorders of brain-gut interaction focused practice (OR 4.80 [2.60-8.84]), and greater perceived effectiveness of neuromodulators (OR 2.75 [1.30-5.84]). Compared to gastroenterologists, experts prescribed neuromodulators to a higher percentage of their patients with IBS (41%-50% vs 21%-30%; P = 0.019) and more frequently found neuromodulators effective (70% vs 27%; P = 0.003). However, concern about side effects was the most common barrier to neuromodulator use (59%).

CONCLUSIONS

The majority of US gastroenterologists believe central neuromodulators are important in treating IBS, and 27% believe they are effective in most patients. High prescribers are in academic practice, focus in IBS and perceive central neuromodulators as effective. Education is needed to improve gastroenterologists' prescribing behaviour.

Anti-inflammatory and tight junction protective activity of the herbal preparation STW 5-II on mouse intestinal organoids

BACKGROUND

Irritable bowel syndrome (IBS) is a functional bowel disorder, in which recurrent abdominal pain is associated with defecation or a change in bowel habits. STW 5-II is a combination of six medicinal herbs with a clinically proven efficacy in managing IBS.

AIM

This study aims to establish an in vitro IBS model using mouse intestinal organoids and to explore the anti-inflammatory and tight junction protective activities of the multi-herbal preparation STW 5-II.

METHODS

Intestinal organoids were cultured in 1:1 Matrigel™ and medium domes. Inflammation and tight junction disruption were induced by a cocktail of cytokines (TNFα, IFNγ, IL-1β, IL-6) and bacterial proteins (LPS, flagellin). Organoids were treated with different concentrations of STW 5-II, and its multi-target activity was assessed using microarray analyses, RT-qPCR, immunofluorescence, western blot, immunohistochemistry, and a FITC permeability assay. In addition, we analyzed the expression of pNF-κB, pSTAT1, iNOS and ZO-1. In silico analyses were conducted to predict and identify the active components that may be responsible in mediating the multi-target anti-inflammatory activity of STW 5-II.

RESULTS

An organoid based IBS model was successfully established. STW 5-II effectively reduced the cytokines-induced overexpression of the pro-inflammatory mediators pNF-κB, pSTAT1 and iNOS. Moreover, STW 5-II attenuated cytokine-mediated downregulation of the tight junction protein, ZO-1. This finding was confirmed by a FITC permeability assay. In silico analyses revealed a promising inhibitory activity of some isolated compounds from STW 5-II against NF-κB, STAT1 and iNOS.

CONCLUSION

STW 5-II possesses multiple anti-inflammatory as well as tight junction protective activities that could explain its clinically proven efficacy in managing IBS symptoms.

Central Sensitivity and Fibromyalgia

Fibromyalgia presents with symptoms of widespread pain, fatigue, sleeping and cognitive disturbances as well as other somatic symptoms. It often overlaps with other conditions termed 'central sensitivity syndromes' such as irritable bowel syndrome, chronic fatigue syndrome and temporomandibular disorder. Central sensitisation, mediated by amplified processing in the central nervous system, has been identified as the key pathogenic mechanism in these disorders. The term 'central sensitivity' can be used to collectively describe the clinical presentation of these disorders. Fibromyalgia is highly prevalent in most rheumatic diseases as well as non-rheumatic chronic diseases and if unrecognised results in high morbidity. It is diagnosed clinically after excluding important differential diagnoses. Diagnostic criteria have been developed as tools to help identify and diagnose fibromyalgia. Such tools can fulfill an important need when managing patients with rheumatic disease and other chronic diseases as a way to identify fibromyalgia and improve patient outcomes. Treatment involves an integrated approach including education, exercise, stress reduction and pharmacological therapies targeting the central nervous system. This approach is suitable for all presentations of central sensitivity and some central sensitivity syndromes have additional treatment options specific to the clinical presentation. This article is protected by copyright. All rights reserved.

IBS Patients' Treatment Expectancy and Motivation Impacts Quality of the Therapeutic Alliance With Provider: Results of the IBS Outcome Study

BACKGROUND

In the absence of a satisfactory medical or dietary treatment, the quality of the therapeutic alliance between irritable bowel syndrome (IBS) patients and their provider is deemed critical to managing refractory IBS. Surprisingly, little research has been conducted on the nature of the therapeutic alliance, factors that influence it, or practical strategies to improve it. This study sought to identify actionable variables that impact therapeutic alliance in patients with refractory IBS.

METHODS

Subjects included a total of 436 Rome III-diagnosed IBS patients (80% female, mean age=41.39 y) who completed a battery of clinical measures at the beginning of the acute treatment phase of an National Institutes of Health (NIH) behavioral trial. Pretreatment candidate predictor variables were organized into 4 categories: sociodemographic, extraintestinal, interpersonal, clinical (eg, symptom severity, pain intensity), cognitive (eg, treatment motivation, expectancy for improvement). Alliance was assessed by patient and clinician-rated measures of the Working Alliance Inventory after first treatment session.

RESULTS

Patient reports of alliance were most strongly and consistently predicted by patient access to interpersonal support [β=0.16; 95% confidence interval (CI)=0.07-0.25], motivation for IBS symptom improvement (β=0.12; 95% CI=0.02-0.21), and expectancy of IBS symptom improvement (β=0.35; 95% CI=0.25-0.44). Therapist ratings of alliance also were predicted by patient expectancy of IBS symptom improvement (β=0.16; 95% CI=0.05-0.26).

CONCLUSION

When managing IBS, a focus on dynamic factors of treatment motivation, social support, and treatment expectancy may be useful in improving the quality of the therapeutic alliance between patient and clinical gastroenterologist.

The self-management work of food hypersensitivity

Background

Food hypersensitivity (FH) has received considerable attention in the scientific community in recent years. However, little attention has been given to the efforts people make to manage their FH. We aimed to explore these efforts by using Normalization Process Theory, which is a conceptual framework formerly used to describe the self-management ‘work’ of long-term conditions.

Methods

We carried out qualitative individual interviews with 16 women with FH. Transcripts from recorded interviews were analyzed using template analysis.

Results

16 women participated; some had diagnoses from conventional medicine (celiac disease, lactose intolerance, food allergies, irritable bowel syndrome) and some did not. Participants described carrying out several tasks, some of which were time-consuming, to manage their FH. Women who had clarified once and for all what food(s) caused symptoms, described that they could concentrate on carrying out a restricted diet, which could become routine. Conversely, participants who had not achieved such clarification described carrying out tasks to identify what food(s) caused symptoms, and to implement and evaluate a tentative diet. Participants’ descriptions also revealed a heightened vigilance when they ate food that others had prepared, and some made efforts to conceal their FH.

Conclusions

Self-management of FH may, like the self-management of other long-term conditions, imply a large workload and burden of treatment. Efforts made to conceal FH may be considered part of this workload, while help in clarifying which food(s) cause symptoms has the potential to reduce the workload.

The Brain-Gut-Microbiotal Axis: A framework for understanding functional GI illness and their therapeutic interventions

Functional gastrointestinal disorders (FGIDs), characterized by chronic abdominal complaints without a structural or biochemical cause, are common diseases that are frequently encountered by specialists in internal medicine. Collectively, irritable bowel syndrome (IBS) and functional dyspepsia are estimated to affect up to 22% of the population, and are often associated with additional somatic and pain complaints, all without an obvious structural source [1,2]. An appreciation of the current understanding of the mechanistic basis for these disorders is key to developing treatment goals and optimization of patient management strategies. In recent years, the brain-gut axis increasingly has been recognized as a central factor in the experience of functional abdominal pain disorders, including the most recent Rome IV guidelines which identify FGIDs as disorders of gut-brain interaction [3]. The brain-gut axis (BGA), simply defined, is a complex network of bidirectional communication between the central and enteric nervous systems. This axis broadly includes all the systems involved with communication between the GI tract and central nervous system (CNS), with principle inputs into this network occurring between the CNS, enteric nervous system (ENS), and autonomic nervous systems (ANS), but also includes interfaces with numerous other factors, including endocrine hormones and immune effector cells as well as interactions with the gut microbiota. Perturbances to this system have been found to play a critical role in the development of visceral hypersensitivity, bowel dysregulation, and mood. This review will summarize the principle processes involved in the neurologic and biologic function of the brain-gut axis, our current understanding of its role in functional GI disorders, and potential targets for therapeutic intervention.

Study of Antispasmodic and Antidiarrheal Activities of Tagetes lucida (Mexican Tarragon) in Experimental Models and Its Mechanism of Action

Tagetes lucida has been used in traditional medicine as a remedy to alleviate several gastrointestinal disorders that provoke stomachaches, abdominal cramps, and diarrhea. However, there is not enough scientific evidence that supports these effects. Therefore, the purpose of this study was to evaluate antispasmodic and antidiarrheal activities of aqueous extract of T. lucida (AqExt-TL) as well as its mechanism of action in experimental models. Antispasmodic activity and the mechanism of action of AqExt-TL were assessed on segments of the guinea pig ileum precontracted with KCl, acetylcholine (ACh), or electrical field stimulation (EFS). Furthermore, the antispasmodic effect of two coumarins (umbelliferone and herniarin) previously identified in this species was evaluated. Antidiarrheal activity of AqExt-TL was determined using the charcoal meal test in mice. AqExt-TL showed antispasmodic activity in segments of the guinea pig ileum precontracted with KCl (83.7 ± 1.9%) and ACh (77.2 ± 5.3%) at the maximal concentration; however, practically, it did not alter the contractions induced by EFS (10.1 ± 2.2%). Antispasmodic activity of AqExt-TL was not significantly altered by hexamethonium (a ganglionic blocker) or L-NAME (an inhibitor of nitric oxide synthase). However, this extract decreased the maximal contractile response to calcium (82.7 ± 8.5%), serotonin (68.1 ± 8.5%), and histamine (63.9 ± 5.9%) in their concentration-response curves. Umbelliferone and herniarin also induced an antispasmodic effect on tissues precontracted with KCl. In addition, low doses of AqExt-TL reduced to 50% the distance traveled by charcoal meal in the gastrointestinal transit model in mice as loperamide, an antidiarrheal agent, did. These results provided evidence of the antispasmodic and antidiarrheal activity of T. lucida, which supports its use in the folk medicine in relieving symptoms in some gastrointestinal disorders. In the antispasmodic effect, the blockade of histaminergic and serotoninergic pathway as well as the calcium channels seems to be involved. Finally, umbelliferone and herniarin could be partially responsible for the antispasmodic activity induced by T. lucida.

Adult Stress Promotes Purinergic Signaling to Induce Visceral Pain in Rats with Neonatal Maternal Deprivation

Chronic visceral pain is one of the primary symptoms of patients with irritable bowel syndrome (IBS), which affects up to 15% of the population world-wide. The detailed mechanisms of visceral pain remain largely unclear. Our previous studies have shown that neonatal maternal deprivation (NMD) followed by adult multiple stress (AMS) advances the occurrence of visceral pain, likely due to enhanced norepinephrine (NE)-β₂ adrenergic signaling. This study was designed to explore the roles of P2X3 receptors (P2X3Rs) in the chronic visceral pain induced by combined stress. Here, we showed that P2X3Rs were co-expressed in β₂ adrenergic receptor (β₂-AR)-positive dorsal root ganglion neurons and that NE significantly enhanced ATP-induced Ca²⁺ signals. NMD and AMS not only significantly increased the protein expression of P2X3Rs, but also greatly enhanced the ATP-evoked current density, number of action potentials, and intracellular Ca²⁺ concentration of colon-related DRG neurons. Intrathecal injection of the P2X3R inhibitor A317491 greatly attenuated the visceral pain and the ATP-induced Ca²⁺ signals in NMD and AMS rats. Furthermore, the β₂-AR antagonist butoxamine significantly reversed the expression of P2X3Rs, the ATP-induced current density, and the number of action potentials of DRG neurons. Overall, our data demonstrate that NMD followed by AMS leads to P2X3R activation, which is most likely mediated by upregulation of β₂ adrenergic signaling in primary sensory neurons, thus contributing to visceral hypersensitivity.

A Qualitative Study of the Experiences of Complementary and Alternative Medicine of Patients With IBS-C

The aim of this study was to examine the complementary and alternative medicine (CAM) experiences of patients with constipation irritable bowel syndrome (IBS-C). This qualitative study consisted of a total of 30 patients, who were admitted to a university hospital in Turkey. Data were collected using a descriptive questionnaire and a semistructured interview. Data analysis identified 5 main themes: (1) constipation-related difficulties experienced due to IBS, (2) the feeling that the CAM use is natural and useful, (3) the effect of the environmental stimuli in preferring the use of CAM, (4) the feeling that CAM is not negative and relieves, and (5) suggesting the CAM use. In conclusion, it was determined that all the patients with constipation IBS used various CAM methods. It may be recommended to raise the awareness of the patients by health care professionals about the CAM methods that may be useful.

A Qualitative Study of the Experiences of Complementary and Alternative Medicine Use in Patients With IBS-C

The aim of this study was to explore the experiences of complementary and alternative medicine (CAM) among patients with constipation irritable bowel syndrome (IBS-C). This qualitative study consisted of a total of 30 patients who were admitted to a university hospital in Turkey. Data were collected using a descriptive questionnaire and a semistructured interview. Data analysis identified 5 main themes: (1) the constipation-associated difficulties experienced because of IBS; (2) the feeling that CAM is natural and useful; (3) the effect of environmental stimuli in preferring the use of CAM; (4) the feeling that CAM is not negative and relieves symptoms; and (5) suggesting the use of CAM. In conclusion, it was determined that all the patients with IBS-C used various CAM methods. It may be recommended that health care professionals should raise awareness among patients about CAM methods that may be useful.

Neonatal Maternal Deprivation Followed by Adult Stress Enhances Adrenergic Signaling to Advance Visceral Hypersensitivity

The pathophysiology of visceral pain in patients with irritable bowel syndrome remains largely unknown. Our previous study showed that neonatal maternal deprivation (NMD) does not induce visceral hypersensitivity at the age of 6 weeks in rats. The aim of this study was to determine whether NMD followed by adult stress at the age of 6 weeks induces visceral pain in rats and to investigate the roles of adrenergic signaling in visceral pain. Here we showed that NMD rats exhibited visceral hypersensitivity 6 h and 24 h after the termination of adult multiple stressors (AMSs). The plasma level of norepinephrine was significantly increased in NMD rats after AMSs. Whole-cell patch-clamp recording showed that the excitability of dorsal root ganglion (DRG) neurons from NMD rats with AMSs was remarkably increased. The expression of β₂ adrenergic receptors at the protein and mRNA levels was markedly higher in NMD rats with AMSs than in rats with NMD alone. Inhibition of β₂ adrenergic receptors with propranolol or butoxamine enhanced the colorectal distention threshold and application of butoxamine also reversed the enhanced hypersensitivity of DRG neurons. Overall, our data demonstrate that AMS induces visceral hypersensitivity in NMD rats, in part due to enhanced NE-β₂ adrenergic signaling in DRGs.

New Protocol for Production of Reduced-Gluten Wheat Bread and Pasta and Clinical Effect in Patients with Irritable Bowel Syndrome: A randomised, Double-Blind, Cross-Over Study

It has been suggested that sourdough fermented products have beneficial health effects. Fungal proteases and selected sourdough lactic acid bacteria were used to produce wheat bread and pasta with a reduced-gluten content (<50% of traditional products). Fermentable oligo-, di- and mono- saccharides and polyols and amylase/trypsin inhibitors were also evaluated. The sensorial features of new products were similar to traditional ones. The efficacy of these new products in reducing the severity of symptoms in Irritable Bowel Syndrome (IBS) patients were compared to traditional bread and pasta using a randomized, crossover-controlled trial. While on a strict gluten-free diet, patients were randomized to consume a reduced- or normal-gluten diet for 2weeks; then, patients from both arms started the wash-out period of one week, and subsequently started the final 2-week period on a normal or reduced-gluten diet. Compared to normal-gluten content, the administration of a reduced-gluten content diet resulted in a decrease of the Visual Analogue Scale score (p = 0.042), while no differences were found in the IBS-Severity Score, Hospital Anxiety and Depression Scale, and IBS-Quality of Life. Data herein reported are novel encouraging findings that should spur a new avenue of research aiming to develop products specifically designed for IBS patients.

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.

Chronic abdominal pain in irritable bowel syndrome - current and future therapies

INTRODUCTION

Irritable bowel syndrome (IBS) is a functional gut disorder that typically manifests in early adult years. One of the two major symptoms of the disease is chronic, visceral pain. The patients report pain as the most distressing symptom with the greatest impact on quality of life, challenging both to patients and healthcare providers. Areas covered: This review focuses on the pathophysiology of abdominal pain in IBS and describes current treatment possibilities. It also covers latest findings that may lead to novel pharmacological options in IBS pain management. Expert commentary: Pain is the main contributor to severity in IBS. Seeking pain alleviation is the most common reason that IBS sufferers consult with their physicians. Not all patients report being satisfied with available treatments for pain in IBS and there is a pressing need to find new, more efficient therapies for this syndrome.

Assessment of Serum sTREM-1 as a Marker of Subclinical Inflammation in Diarrhea-Predominant Patients with Irritable Bowel Syndrome

BACKGROUND

Irritable bowel disease (IBS) is viewed upon as a functional disorder of subclinical inflammatory changes in recent years, and there is no reliable biomarker. Triggering receptor expressed on myeloid cells 1 (TREM-1), also produced in a soluble form (sTREM-1), is involved in the activation of inflammatory cascades of intracellular events and may play a role in pathogenesis of IBS.

AIM

To investigate whether serum sTREM-1 level can be used as a marker of subclinical inflammation in D-IBS.

METHODS

Abdominal pain was quantified by a validated questionnaire. Expression level of TREM-1 in colonic mucosa as well as sTREM-1 level in serum was also detected. Furthermore, we investigated the involvement of TREM-1-associated macrophage activation in IBS-like visceral hypersensitivity.

RESULTS

No evidence for obvious inflammation was found in D-IBS patients. Serum sTREM-1 level in D-IBS patients was significantly higher than that in HCs, which was also significantly correlated with abdominal pain scores. We showed a marked increase in the proportion of TREM-1-expressing macrophages in D-IBS, which was significantly correlated with abdominal pain scores. Functionally, gadolinium chloride (GdCl₃), a macrophage selective inhibitor, or LP17, the TREM-1-specific peptide, significantly suppressed the visceral hypersensitivity in trinitrobenzene sulfonic acid (TNBS)-treated mice with IBS-like visceral hypersensitivity.

CONCLUSIONS

Serum sTREM-1 level is significantly higher in D-IBS patients and positively correlates with abdominal pain, which may be initiated by TREM-1-associated macrophage activation, indicating the existence of subclinical inflammation in D-IBS. Therefore, serum sTREM-1 is a potential marker of subclinical inflammation in D-IBS.

Comparison of Symptoms, Healthcare Utilization, and Treatment in Diagnosed and Undiagnosed Individuals With Diarrhea-Predominant Irritable Bowel Syndrome

OBJECTIVES

Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by symptoms including abdominal pain and altered bowel function. Up to 75% of individuals with IBS may be undiagnosed. The aim of this study was to characterize symptoms, healthcare utilization, and treatments in populations with both diagnosed and undiagnosed IBS.

METHODS

An online survey was conducted to compare gastrointestinal (GI) symptoms, healthcare visits, well-being, symptom management, and treatment satisfaction in individuals with and without medically diagnosed IBS (Rome III criteria). Symptom severity, disruptiveness, and treatment satisfaction were rated using a 7-point scale. Adjustments to daily life were determined by predefined survey responses.

RESULTS

A total of 1,924 individuals with a history of GI symptoms were eligible and completed the survey. Of these, 1,094 individuals (56.9%) met the criteria for IBS; 830 individuals (43.1%) had no medical diagnosis of IBS despite meeting diagnostic criteria. Most participants received a diagnosis from either gastroenterologists (45%) or primary care physicians (42%). A greater percentage of diagnosed patients had severe GI symptoms (score ≥6) vs. undiagnosed individuals (16% vs. 8%, respectively; P<0.05); diagnosed patients were more likely to report that GI symptoms adversely affected their quality of life. Approximately 40% of participants received IBS-related treatment from primary care physicians; 26% and 43% of diagnosed and undiagnosed individuals, respectively, were not receiving treatment for GI symptoms.

CONCLUSIONS

Many individuals with IBS-related symptoms have not been medically diagnosed with IBS. IBS-related symptoms impact quality of life, yet more than one-third of individuals are not receiving treatment for IBS.

High throughput RNA sequencing utility for diagnosis and prognosis in colon diseases

RNA sequencing is the use of high throughput next generation sequencing technology to survey, characterize, and quantify the transcriptome of a genome. RNA sequencing has been used to analyze the pathogenesis of several malignancies such melanoma, lung cancer, and colorectal cancer. RNA sequencing can identify differential expression of genes (DEG's), mutated genes, fusion genes, and gene isoforms in disease states. RNA sequencing has been used in the investigation of several colorectal diseases such as colorectal cancer, inflammatory bowel disease (ulcerative colitis and Crohn's disease), and irritable bowel syndrome.

Low FODMAPs and gluten-free foods for irritable bowel syndrome treatment: Lights and shadows

Irritable bowel syndrome (IBS) is a functional bowel disorder with a global prevalence of 10-20% and in which abdominal pain or discomfort is associated with defecation or a change in bowel habit. IBS strongly impairs quality of life, social function, work productivity, and brings substantial costs to health care services. The etiology of IBS remains poorly understood and the search for biomarkers is ongoing. Bloating, distension, and disordered defecation are commonly associated features. The role of dietary components in inducing IBS symptoms is difficult to explore. To date, foods are not generally considered a cause but rather symptom-triggering factors, and are a significant component of the management pathway for many individuals. The use of functional foods in the management of IBS has been limited to dairy products, with particular interest in the use of probiotics. Particular interest has been given to gluten-free and low fermentable oligosaccharides, disaccharides, monosaccharides, and polyol (FODMAP) approach to treatment of IBS. There is scope to modify some of the existing products in the cereal market, in such a way that they would then comply with the gluten-free/low FODMAP diet. This modification could then in turn, help individual patients to experience a beneficial reduction in the symptoms of IBS. This literature review is intended to provide a discussion on the diet disease link between IBS and gluten-free/low FODMAP diet, for the purpose of creating an academic foundation on which to develop functional foods, suitable for patients with IBS.

Economic burden of inadequate symptom control among US commercially insured patients with irritable bowel syndrome with diarrhea

AIMS

To assess healthcare resource use and costs among irritable bowel syndrome (IBS) with diarrhea (IBS-D) patients with and without evidence of inadequate symptom control on current prescription therapies and estimate incremental all-cause costs associated with inadequate symptom control.

METHODS

IBS-D patients aged ≥18 years with ≥1 medical claim for IBS (ICD-9-CM 564.1x) and either ≥2 claims for diarrhea (ICD-9-CM 787.91, 564.5x), ≥1 claim for diarrhea plus ≥1 claim for abdominal pain (ICD-9-CM 789.0x), or ≥1 claim for diarrhea plus ≥1 pharmacy claim for a symptom-related prescription within 1 year of an IBS diagnosis were identified from the Truven Health MarketScan database. Inadequate symptom control, resource use, and costs were assessed up to 1 year following the index date. Inadequate symptom control included any of the following: (1) switch or (2) addition of new symptom-related therapy; (3) IBS-D-related inpatient or emergency room (ER) admission; (4) IBS-D-related medical procedure; (5) diagnosis of condition indicating treatment failure; or (6) use of a more aggressive prescription. Generalized linear models assessed incremental costs of inadequate symptom control.

RESULTS

Of 20,624 IBS-D patients (mean age = 48.5 years; 77.8% female), 66.4% had evidence of inadequate symptom control. Compared to those without inadequate symptom control, patients with evidence of inadequate symptom control had significantly more hospitalizations (12.0% vs 6.0%), ER visits (37.1% vs 22.6%), use of outpatient services (73.0% vs 60.7%), physician office visits (mean 11.0 vs 8.1), and prescription fills (mean 40.0 vs 26.7) annually (all p < .01). Incremental costs associated with inadequate symptom control were $3,065 (2013 US dollars), and were driven by medical service costs ($2,391; 78%).

LIMITATIONS

Study included US commercially insured patients only and inferred IBS-D status and inadequate symptom control from claims.

CONCLUSIONS

Inadequate symptom control associated with available IBS-D therapies represents a significant economic burden for both payers and IBS-D patients.

Efficacy of double-coated probiotics for irritable bowel syndrome: a randomized double-blind controlled trial

BACKGROUND

The purpose of this study was to elucidate the effects of a dual-coated probiotic supplement (Duolac Care) on symptoms of diarrhea-predominant irritable bowel syndrome in a randomized double-blind clinical trial.

METHODS

Fifty subjects with diarrhea-predominant irritable bowel syndrome were randomly assigned to either the non-coating group or the dual-coating group in order to receive two capsules per day of multi-species probiotics containing 5 billion bacteria per capsule for 4 weeks. Data from an adequate relief questionnaire were used in assessment of primary outcome. Daily records of stool frequencies and the Bristol stool scale, a weekly symptom diary using 100-mm visual analog scale, and Beck depression inventories were collected. Blood tests including blood cell counts, interleukin-10, tumor necrosis factor-alpha and inducible nitric oxide synthase, and regulatory T cells-CD4 + CD25^high T cells, CD4 + LAP + T cells and CD25^high + LAP + T cells-were analyzed before and after the study. The shift of gut microbiota was investigated using a quantitative real-time polymerase chain reaction assay.

RESULTS

Responses to the adequate relief questionnaire indicated significant improvement in overall discomfort in the dual-coating group and the ratio of normal stools to hard or watery stools had a better effect from dual-coated probiotics compared to non-coated probiotics. This may be due to a shift of intestinal microbiota, as our correlation analysis showed significant negative correlation between Bifidobacterium and urgency of defecation.

CONCLUSIONS

Our result implies that dual-coating layers of probiotic supplement can be a candidate for treatment of diarrhea-predominant irritable bowel syndrome.

Efficacy and safety of enteric coated capsules of anise oil to treat irritable bowel syndrome

ETHNOPHARMACOLOGICAL RELEVANCE

Anise is a well-recognized plant in Traditional Persian Medicine (TPM) sources. Anise oil has been suggested for the treatment of bowel disorders in Persian medical textbooks. Based on TPM scholars, this ingredient has a favorable effect on gastrointestinal diseases. We did this trial to determine the efficacy and safety of enteric coated capsules of anise oil for clinical symptoms of irritable bowel syndrome (IBS).

METHODS AND MATERIALS

This three-armed double-blind clinical trial was carried out from August 2014 to February 2015. 120 patients were divided into three groups by block randomization: AnisEncap, placebo and Colpermin®. Patients in each group received 3 similar capsules per day for 4 weeks. The primary outcome was measured as a visual analogue scale (VAS) score, and the secondary outcome was assessed with an IBS-quality of life questionnaire. Chi-squared tests were used for categorical variables and t-tests to compare continuous variables.

RESULTS

There were no significant differences in demographic characteristics among the three groups. According to intention-to-treat sample analysis, 75% of patients in the treatment group, 35% in the placebo group and 52.5% in active control group were free from IBS symptoms (P<0.001). The effectiveness of AnisEncap in improving IBS symptoms (abdominal discomfort or pain, bloating, diarrhea, constipation severity, difficulty in defecation, gastroesophageal reflux, headache, tiredness, overall satisfaction and quality of life) was significantly greater than placebo or Colpermin® after the 4-week treatment period and the 2-week follow-up period (P<0.0001). The number needed to treat for enteric coated capsules of anise oil was 4, which indicated significantly superior efficacy compared to the other two groups (P<0.001).

CONCLUSION

The effectiveness of AnisEncap was superior to that of placebo or Colpermin® in patients with IBS. Further studies are suggested to find the main mechanism of action of anise oil in this regard.

Regulation of the serotonin transporter in the pathogenesis of irritable bowel syndrome

Serotonin (5-HT) and the serotonin transporter (SERT) have earned a tremendous amount of attention regarding the pathogenesis of irritable bowel syndrome (IBS). Considering that enteric 5-HT is responsible for the secretion, motility and perception of the bowel, the involvement of altered enteric 5-HT metabolism in the pathogenesis of IBS has been elucidated. Higher 5-HT availability is commonly associated with depressed SERT mRNA in patients with IBS compared with healthy controls. The expression difference of SERT between IBS patients and healthy controls might suggest that SERT plays an essential role in IBS pathogenesis, and SERT was expected to be a novel therapeutic target for IBS. Progress in this area has begun to illuminate the complex regulatory mechanisms of SERT in the etiology of IBS. In this article, current insights regarding the regulation of SERT in IBS are provided, including aspects of SERT gene polymorphisms, microRNAs, immunity and inflammation, gut microbiota, growth factors, among others. Potential SERT-directed therapies for IBS are also described. The potential regulators of SERT are of clinical importance and are important for better understanding IBS pathophysiology and therapeutic strategies.

Effects of synbiotic fermented milk containing Lactobacillus acidophilus La-5 and Bifidobacterium animalis ssp. lactis BB-12 on the fecal microbiota of adults with irritable bowel syndrome: A randomized double-blind, placebo-controlled trial

We conducted a randomized double-blind, placebo-controlled multicentric study to investigate the influence of a synbiotic fermented milk on the fecal microbiota composition of 30 adults with irritable bowel syndrome (IBS). The synbiotic product contained Lactobacillus acidophilus La-5, Bifidobacterium animalis ssp. lactis BB-12, Streptococcus thermophilus, and dietary fiber (90% inulin, 10% oligofructose), and a heat-treated fermented milk without probiotic bacteria or dietary fiber served as placebo. Stool samples were collected after a run-in period, a 4-wk consumption period, and a 1-wk follow-up period, and were subjected to real-time PCR and 16S rDNA profiling by next-generation sequencing. After 4wk of synbiotic (11 subjects) or placebo (19 subjects) consumption, a greater increase in DNA specific for L. acidophilus La-5 and Bifidobacterium animalis ssp. lactis was detected in the feces of the synbiotic group compared with the placebo group by quantitative real-time PCR. After 1wk of follow-up, the content of L. acidophilus La-5 and B. animalis ssp. lactis decreased to levels close to initial levels. No significant changes with time or differences between the groups were observed for Lactobacillus, Enterobacteriaceae, Bifidobacterium, or all bacteria. The presence of viable BB-12- and La-5-like bacteria in the feces resulting from the intake of synbiotic product was confirmed by random amplification of polymorphic DNA (RAPD)-PCR. At the end of consumption period, the feces of all subjects assigned to the synbiotic group contained viable bacteria with a BB-12-like RAPD profile, and after 1wk of follow-up, BB-12-like bacteria remained in the feces of 87.5% of these subjects. The presence of La-5-like colonies was observed less frequently (37.5 and 25% of subjects, respectively). Next-generation sequencing of 16S rDNA amplicons revealed that only the percentage of sequences assigned to Strep. thermophilus was temporarily increased in both groups, whereas the global profile of the fecal microbiota of patients was not altered by consumption of the synbiotic or placebo. In conclusion, daily consumption of a synbiotic fermented milk had a short-term effect on the amount and proportion of La-5-like strains and B. animalis ssp. lactis in the fecal microbiome of IBS patients. Furthermore, both synbiotic and placebo products caused a temporary increase in fecal Strep. thermophilus.