Epidemiology of irritable bowel syndrome in Asia: something old, something new, something borrowed

The Disease Spectrum and Natural History of Patients With Abdominal Bloating or Distension: A Longitudinal Study

Background/Aims

Abdominal bloating or distension (AB/D) is a common complaint in the outpatient of gastroenterology department. Since the potential contributors are numerous and complex, a longitudinal study on the disease spectrum and natural history of patients was performed to better understand the key factors of AB/D.

Methods

Consecutive patients with the chief complaint of AB/D referred to the outpatient clinic were screened. Functional gastrointestinal disorders (FGIDs) were diagnosed according to Rome IV criteria. A 3-year follow-up was performed to seek for the changes in symptoms as well as disease spectrum.

Results

A total of 261 participants were enrolled and 139 completed the follow-up. Most patients suffered from moderate to severe symptoms more than 1 day per week. Common causes of AB/D were FGIDs (51.7%) and organic diseases (17.2%). The latter group was older with lower body mass index (BMI). Functional dyspepsia was the most common type of FGIDs in AB/D. The symptoms of 18.0% of participants failed to improve at the end of the 3-year follow-up, and those diagnosed with FGIDs were most likely to continue to suffer. Abdominal pain was a positive predictive factor for good prognosis in the FGIDs group. Besides, only 22.7% of participants had a consistent diagnosis of FGIDs during follow-up.

Conclusions

FGIDs are the most common diagnosis in patients with AB/D. Symptoms were especially hard to be improved. Classification diagnoses of FGIDs in AB/D patients fluctuated significantly over time.

The influence of Nav1.9 channels on intestinal hyperpathia and dysmotility

The Nav1.9 channel is a voltage-gated sodium channel. It plays a vital role in the generation of pain and the formation of neuronal hyperexcitability after inflammation. It is highly expressed in small diameter neurons of dorsal root ganglions and Dogiel II neurons in enteric nervous system. The small diameter neurons in dorsal root ganglions are the primary sensory neurons of pain conduction. Nav1.9 channels also participate in regulating intestinal motility. Functional enhancements of Nav1.9 channels to a certain extent lead to hyperexcitability of small diameter dorsal root ganglion neurons. The hyperexcitability of the neurons can cause visceral hyperalgesia. Intestinofugal afferent neurons and intrinsic primary afferent neurons in enteric nervous system belong to Dogiel type II neurons. Their excitability can also be regulated by Nav1.9 channels. The hyperexcitability of intestinofugal afferent neurons abnormally activate entero-enteric inhibitory reflexes. The hyperexcitability of intrinsic primary afferent neurons disturb peristaltic waves by abnormally activating peristaltic reflexes. This review discusses the role of Nav1.9 channels in intestinal hyperpathia and dysmotility.

Sex steroid metabolism and action in colon health and disease

The colon is the largest hormonally active tissue in the human body. It has been known for over a hundred years that various hormones and bioactive peptides play important roles in colon function. More recently there is a growing interest in the role the sex steroids, oestrogens and androgens, may play in both normal colon physiology and colon pathophysiology. In this review, we examine the potential role oestrogens and androgens play in the colon. The metabolism and subsequent action of sex steroids in colonic tissue is discussed and how these hormones impact colon motility is investigated. Furthermore, we also determine how oestrogens and androgens influence colorectal cancer incidence and development and highlight potential new therapeutic targets for this malignancy. This review also examines how sex steroids potentially impact the severity and progression of other colon disease, such as diverticulitis, irritable bowel syndrome, and polyp formation.

Cognition of abdominal pain and abdominal discomfort in Chinese patients with irritable bowel syndrome with diarrhea

BACKGROUND

In Asia, the proportion of patients with irritable bowel syndrome (IBS) with abdominal discomfort alone is significantly higher than that in western countries. The purposes of this study are to understand the cognition of abdominal pain and abdominal discomfort in Chinese patients with IBS and to compare the clinical characteristics of patients with abdominal pain alone and with abdominal discomfort alone.

METHODS

Patients with IBS with diarrhea (IBS-D) who met the Rome III diagnostic criteria and had episodes of at least one day/week were consecutively enrolled. The cognition of abdominal pain and abdominal discomfort were investigated through face-to-face unstructured interview. Patients were divided into a pain group and a discomfort group according to the cognition interviews, then the characteristics and severity of symptoms (IBS symptom severity scale, IBS-SSS), IBS quality of life (IBS-QOL) and psychological state were compared between groups.

RESULTS

A total of 88 patients with IBS-D were enrolled. Most of the patients with self-reported abdominal pain described their pain as spasm/cramping; patients with self-reported abdominal discomfort had as many as 24 different descriptions of discomfort. Most patients having abdominal pain and discomfort could accurately distinguish the two symptoms. The degree of abdominal pain in the pain group was higher than abdominal discomfort in the discomfort group (P = 0.002). There was no significant difference in IBS-SSS, extra-intestinal pain, IBS-QOL, and psychological state between the two groups.

CONCLUSIONS

For Chinese patients with IBS-D, abdominal pain and abdominal discomfort are two different symptoms, but they have similar clinical features.

TRIAL REGISTRATION

ChiCTR, ChiCTR1900028082. Registered 11 December 2019 - Retrospectively registered, http://www.chictr.org.cn .

Patients' perspectives on irritable bowel syndrome: a qualitative analysis based on social media in China

AIM

To explore the perspectives, experience, and concerns of patients with irritable bowel syndrome (IBS) in China.

METHODS

We used data mining to investigate posts shared in Baidu Tieba concerned with IBS; we collected the data through the crawler code, and mined the cleaned data's themes based on Latent Dirichlet allocation (LDA) and the Grounded theory.

RESULTS

We found 5746 network posts related to IBS. LDA analysis generated 20 topics, and grounded theory analysis established eight topics. Combining the two methods, we finally arranged the topics according to five concepts: difficulty in obtaining disease information; serious psychosocial problems; dissatisfied with the treatment; lack of social support; and low quality of life.

CONCLUSION

Social media research improved patient-centric understanding of patients' experiences and perceptions. Our study may facilitate doctor-patient communication and assist in the formulation of medical policies.

Irritable bowel syndrome: Epidemiology, overlap disorders, pathophysiology and treatment

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disease with a significant impact on patients' quality of life and a high socioeconomic burden. And the understanding of IBS has changed since the release of the Rome IV diagnosis in 2016. With the upcoming Rome V revision, it is necessary to review the results of IBS research in recent years. In this review of IBS, we can highlight future concerns by reviewing the results of IBS research on epidemiology, overlap disorders, pathophysiology, and treatment over the past decade and summarizing the latest research.

Efficacy and safety of probiotics in the treatment of irritable bowel syndrome: A systematic review and meta-analysis of randomised clinical trials using ROME IV criteria

BACKGROUND

Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder which affects a great number of patients globally. Clinical trials and meta-analyses have evaluated different therapies for IBS. Some of them have shown that probiotics play a significant role in the management of IBS-patients. Nevertheless, results are controversial, and the efficacy of the administration of probiotics remains to be confirmed, especially in regard to which type of probiotic-strains are beneficial.

AIM

The aim of the present meta-analysis is to assess the efficacy and safety of the administration of probiotics to IBS-patients with a diagnosis based on Rome IV criteria, which is performed for the first time.

METHODS

Electronic databases (Pubmed, Scopus and Cochrane) were searched until 26.01.2023 for randomized controlled trials (RCTs) studying the administration of probiotics in adult IBS-patients, who were categorized according to the Rome IV criteria. The risk of bias was assessed using the Cochrane Risk of Bias tool (ROB) 2.0. Weighted and standardized mean difference with the 95% confidence intervals were used for the synthesis of the results. Primary outcomes were the decrease of IBS-Symptom Severity Score (IBS-SSS) and decrease of abdominal pain. The secondary outcomes were the improvement in quality of life (QoL) and the decrease of bloating. Lastly, the adverse effects of probiotics were evaluated. The protocol of the study has been registered at protocols.io (DOI dx.doi.org/10.17504/protocols.io.14egn218yg5d/v1).

RESULTS

Six double-blind (N = 970) placebo-control RCTs fulfilled the inclusion criteria and overall, nine different strains of probiotics were examined. No significant reduction in IBS-SSS (WMD -43.2, 95% CI -87.5 to 1.0, I2 = 82.9%) was demonstrated, whereas a significant decrease regarding abdominal pain (SMD -0.94, 95% CI -1.53 to -0.35, I2 = 92,2) was shown. Furthermore, no correlation between improvement of QoL and the use of probiotics (SMD -0.64, 95% CI -1.27 to 0.00, I2 = 93,9%) was shown. However, probiotics were associated with a significant reduction in bloating (SMD -0.28, 95% CI -0.47 to -0.09, I2 = 36,0%). A qualitative synthesis was conducted about adverse events and showed that the use of probiotics' is safe without severe adverse events.

CONCLUSIONS

The administration of probiotics to IBS-patients demonstrated a positive effect on pain and bloating, but due to significant heterogeneity and confounding factors, that were not examined in the included studies, a definitive statement cannot be made. Moreover, probiotics did not lead to an improvement in other parameters. There is a need for larger RCTs in IBS-patients diagnosed according to Rome IV (not III) criteria and especially it is essential to be conducted RCTs which examine the administration of specific strains and have similar methodological characteristics.

Indian consensus statements on irritable bowel syndrome in adults: A guideline by the Indian Neurogastroenterology and Motility Association and jointly supported by the Indian Society of Gastroenterology

The Indian Neurogastroenterology and Motility Association (INMA), earlier named the Indian Motility and Functional Diseases Association developed this evidence-based practice guidelines for the management of irritable bowel syndrome (IBS). A modified Delphi process was used to develop this consensus containing 28 statements, which were concerning diagnostic criteria, epidemiology, etiopathogenesis and comorbidities, investigations, lifestyle modifications and treatments. Owing to the Coronavirus disease-19 (COVID-19) pandemic, lockdowns and mobility restrictions, web-based meetings and electronic voting were the major tools used to develop this consensus. A statement was regarded as accepted when the sum of "completely accepted" and "accepted with minor reservation" voted responses were 80% or higher. Finally, the consensus was achieved on all 28 statements. The consensus team members are of the view that this work may find use in teaching, patient care, and research on IBS in India and other nations.

Daikenchuto significantly improves stool consistency and lower gastrointestinal symptoms in patients with chronic constipation

Background and Aim

A number of basic and clinical studies have confirmed that the traditional Japanese herbal medicine, Daikenchutou (DKT) has a pharmacological effect on cholinergic and serotonergic mechanisms with a favorable safety profile and an improving effect on lower gastrointestinal (GI) symptoms including abdominal pain or bloating. The purpose of this study is to evaluate the efficacy and safety of DKT on chronic constipation.

Methods

This multicenter, randomized, placebo-controlled, double-blinded clinical trial enrolled 67 patients with chronic constipation fulfilling Rome III criteria. After a 2-week observation period, 63 patients with persistent symptoms were finally randomized to a 4-week course of treatment with DKT or placebo. The primary endpoint consisted of a global assessment of overall treatment effect (OTE), while the secondary endpoints consisted of improvements in stool consistency, spontaneous bowel movements, lower GI symptoms related to constipation, and quality of life. Factors associated with OTE were also investigated.

Results

After 4 weeks administration of DKT, OTE was significantly higher than placebo. No side effects were observed. Significant improvement in stool consistency and lower GI symptoms was observed in the DKT group. The improvements in lower GI symptoms as well as stool consistency were associated with OTE. OTE was higher in patients with greater improvement in lower GI symptoms with mental component summary scores close to normal before treatment.

Conclusion

DKT was effective and safe in treating chronic constipation, especially in patients having symptoms related to constipation with no impaired mental component summary score.

Asia-Pacific guidelines for managing functional dyspepsia overlapping with other gastrointestinal symptoms

Contemporary systems for the diagnosis and management gastrointestinal symptoms not attributable to organic diseases (Functional GI Disorders, FGID, now renamed Disorders of Gut-Brain Interaction, DGBI) seek to categorize patients into narrowly defined symptom-based sub-classes to enable targeted treatment of patient cohorts with similar underlying putative pathophysiology. However, an overlap of symptom categories frequently occurs and has a negative impact on treatment outcomes. There is a lack of guidance on their management. An Asian Pacific Association of Gastroenterology (APAGE) working group was set up to develop clinical practice guidelines for management of patients with functional dyspepsia (FD) who have an overlap with another functional gastrointestinal disorder: FD with gastroesophageal reflux (FD-GERD), epigastric pain syndrome with irritable bowel syndrome (EPS-IBS), postprandial distress syndrome with IBS (PDS-IBS), and FD-Constipation. We identified putative pathophysiology to provide a basis for treatment recommendations. A management algorithm is presented to guide primary and secondary care clinicians.

LMWP (S3-3) from the Larvae of Musca domestica Alleviate D-IBS by Adjusting the Gut Microbiota

Diarrhea-based Irritable Bowel Syndrome (D-IBS) and diarrhea are both associated with ecological imbalance of the gut microbiota. Low Molecular Weight Peptides (LMWP) from the larvae of Musca domestica have been shown to be effective in the treatment of diarrhea and regulation of gut microbiota. Meanwhile, the single polypeptide S3-3 was successfully isolated and identified from LMWP in our previous studies. It remains unclear exactly whether and how LMWP (S3-3) alleviate D-IBS through regulating gut microbiota. We evaluated the gut microbiota and pharmacology to determine the regulation of gut microbiota structure and the alleviating effect on D-IBS through LMWP (S3-3). The rates of loose stools, abdominal withdrawal reflex (AWR) and intestinal tract motility results revealed that LMWP (S3-3) from the larvae of Musca domestica had a regulating effect against diarrhea, visceral hypersensitivity and gastrointestinal (GI) dysfunction in D-IBS model mice. Additionally, 16S rRNA gene sequencing was utilized to examine the gut microbiota, which suggests that LMWP induce structural changes in the gut microbiota and alter the levels of the following gut microbiota: Bacteroidetes, Proteobacteria and Verrucomicrobia. LMWP putatively functioned through regulating 5-HT, SERT, 5-HT2AR, 5-HT3AR and 5-HT4R according to the results of ELISA, qRT-PCR and IHC. The findings of this study will contribute to further understanding how LMWP (S3-3) attenuate the effects of D-IBS on diarrhea, visceral hypersensitivity and GI dysfunction.

Exploration of "Zhang" in functional gastrointestinal disorders: A cross-cultural challenge in Chinese clinical setting

OBJECTIVES

In China, four symptoms of functional gastrointestinal disorders, postprandial fullness, early satiety, bloating, and abdominal distension are commonly and interchangeably expressed as a single chief complaint, "Zhang". In this study we aimed to explore the most efficient method of determining the characteristics of symptoms in such patients.

METHODS

Consecutive patients with the chief complaint of abdominal "Zhang" from December 2017 to June 2018 were included. Their symptom patterns were determined by face-to-face interviews. Patients with a single symptom (postprandial fullness, early satiety, bloating, or abdominal distension) completed the questionnaire assessing their understanding of the symptoms using three methods including concept terms, pictograms, and verbal descriptions.

RESULTS

A total of 230 patients (121 men, 109 women; mean age 43.7 ± 12.6 y) were included. Verbal descriptions were most applicable to identify patients' symptom patterns, followed by concept terms and pictograms. Early satiety was the most difficult to identify (20.9% agreement between patient's understanding and doctor's diagnosis by using concept term), whereas fullness and bloating had apparently higher recognition (70.7% and 72.1% by concept terms). Elder patients (>60 y) and those with more frequent symptom attacks (≥once daily) showed relatively poorer understanding of the symptoms.

CONCLUSIONS

Early satiety is poorly identified by patients. Existing pictograms fail to show comprehension-improving features in a Chinese cultural setting. Verbal descriptions may be the best option for diagnosing abdominal "Zhang". More caution is required during the inquiry of medical history from elder patients with frequent symptom attacks.

The Prevalence of Irritable Bowel Syndrome Among Chinese University Students: A Systematic Review and Meta-Analysis

Background

Irritable bowel syndrome (IBS) has become a common public health issue among university students, impairing their physical and mental health. This meta-analysis aimed to examine the pooled prevalence of IBS and its associated factors among Chinese university students.

Methods

Databases of PubMed, EMBASE, MEDLINE (via EBSCO), CINAHL (via EBSCO), Wan Fang, CNKI and Weipu (via VIP) were systematically searched from inception date to May 31, 2021. Meta-analysis was performed using random-effects models. Meta-regression and subgroup analysis were used to detect the potential source of heterogeneity.

Key Results

A total of 22 cross-sectional studies (14 were in Chinese and 8 were in English) with 33,166 Chinese university students were included. The pooled prevalence of IBS was estimated as 11.89% (95% CI = 8.06%, 16.35%). The prevalence was 10.50% (95% CI = 6.80%, 15.87%) in Rome II criteria, 12.00% (95% CI = 8.23%, 17.17%) in Rome III criteria, and 3.66% (95% CI = 2.01%, 6.60%) in Rome IV criteria. The highest prevalence of IBS was 17.66% (95% CI = 7.37%, 36.64%) in North China, and the lowest was 3.18% (95% CI = 1.28%, 7.68%) in South China. Subgroup analyses indicated that gender, major, anxiety and depression symptoms, drinking and smoking behaviors were significantly associated with the prevalence of IBS. Meta-regression analyses suggested that region influenced prevalence estimates for IBS.

Conclusions and Inferences

This meta-analysis illustrated that IBS is very common in Chinese university students. Regular screening, effective prevention, and appropriate treatments should be implemented to reduce the risk of IBS in this population. More future studies should be conducted in Northeastern and Southwestern parts of China.

Global prevalence and burden of meal-related abdominal pain

BACKGROUND

Patients with disorders of gut-brain interaction (DGBI) report meal intake to be associated with symptoms. DGBI patients with meal-related symptoms may have more severe symptoms overall and worse health outcomes, but this subgroup has not been well characterized. We aimed to describe the global prevalence of meal-related abdominal pain and characterize this subgroup.

METHODS

The data analyzed originated from the Internet survey component of the population-based Rome Foundation Global Epidemiology Study, completed in 26 countries (n = 54,127). Adult subjects were asked whether they had abdominal pain and how often this was meal-related. Respondents were categorized into "no," "occasional," and "frequent" meal-related abdominal pain groups based on 0%, 10-40%, and ≥50% of the pain episodes being meal-related, respectively. DGBI diagnoses, frequency of other GI symptoms, psychological distress, non-GI somatic symptoms, quality of life, and healthcare utilization were compared between groups. Mixed linear and ordinal regression was used to assess independent associations between psychological distress, non-GI somatic symptoms, quality of life, other GI symptoms, and meal-related abdominal pain.

RESULTS

Overall, 51.9% of the respondents reported abdominal pain in the last 3 months, and 11.0% belonged to the group with frequent meal-related abdominal pain, which included more females and younger subjects. DGBI diagnoses were more common in subjects with frequent meal-related abdominal pain, and the frequency of several GI symptoms was associated with having more frequent meal-related abdominal pain. Having meal-related abdominal pain more frequently was also associated with more severe psychological distress, non-GI somatic symptoms, and a poorer quality of life. The group with frequent meal-related abdominal pain also more often consulted a doctor for bowel problems compared to the other groups of meal-related abdominal pain.

CONCLUSION

Reporting frequent meal-related abdominal pain is common across the globe and associated with other GI and non-GI somatic symptoms, psychological distress, healthcare utilization, and a poorer quality of life. Individuals who frequently experience meal-related abdominal pain also more frequently fulfill the diagnostic criteria for DGBI. Assessing meal-related symptoms in all DGBI patients could be of major importance to improve and individualize symptom management.

Prevalence, clinical characteristics, and management of irritable bowel syndrome in Vietnam: A scoping review

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders worldwide. Its prevalence varies significantly from country to country, largely due to heterogeneity in the available data. Recent studies show that the prevalence of IBS in Asia is on the rise. However, there are very limited data regarding its prevalence in the Vietnamese population. This review aims to offer an overview of the prevalence and clinical characteristics of IBS in the Vietnamese population; and to discuss the current management of IBS in Vietnam-taking into account the available medical resources and the local spectrum of lower gastrointestinal disorders that may mimic IBS.

Impact of the coronavirus disease 2019 pandemic on irritable bowel syndrome

BACKGROUND AND AIM

Gastrointestinal manifestations of the coronavirus disease 2019 (COVID-19) pandemic may mimic irritable bowel syndrome (IBS), and social distancing measures may affect IBS patients negatively. We aimed to study the impact of COVID-19 on respondents with self-reported IBS.

METHODS

We conducted an anonymized survey from May to June 2020 in 33 countries. Knowledge, attitudes, and practices on personal hygiene and social distancing as well as psychological impact of COVID-19 were assessed. Statistical analysis was performed to determine differences in well-being and compliance to social distancing measures between respondents with and without self-reported IBS. Factors associated with improvement or worsening of IBS symptoms were evaluated.

RESULTS

Out of 2704 respondents, 2024 (74.9%) did not have IBS, 305 (11.3%) had self-reported IBS, and 374 (13.8%) did not know what IBS was. Self-reported IBS respondents reported significantly worse emotional, social, and psychological well-being compared with non-IBS respondents and were less compliant to social distancing measures (28.2% vs 35.3%, P = 0.029); 61.6% reported no change, 26.6% reported improvement, and 11.8% reported worsening IBS symptoms. Higher proportion of respondents with no change in IBS symptoms were willing to practice social distancing indefinitely versus those who deteriorated (74.9% vs 51.4%, P = 0.016). In multivariate analysis, willingness to continue social distancing for another 2-3 weeks (vs longer period) was significantly associated with higher odds of worsening IBS.

CONCLUSION

Our study showed that self-reported IBS respondents had worse well-being and compliance to social distancing measures than non-IBS respondents. Future research will focus on occupational stress and dietary changes during COVID-19 that may influence IBS.

Positioning of Bristol Stool Form Scale type 3 in constipation treatment satisfaction: A multicenter study in Japan

BACKGROUND AND AIM

Many patients are not satisfied with chronic constipation (CC) treatments. The aim of this study was to identify factors linked to CC treatment satisfaction or dissatisfaction.

METHODS

Our study population included patients who received CC treatment at a clinic or hospital. CC was diagnosed by a physician based on the patient's complaint. Treatment satisfaction was evaluated using the 28th question of the Patient Assessment of Constipation Quality of Life questionnaire.

RESULTS

We conducted this study at 28 facilities. We included 167 patients (mean age 66.7 ± 15.2 years, male:female ratio is 1:3.07). Sixty-eight (40.7%) of patients were satisfied with their constipation treatment. Treatment dissatisfaction of CC was significantly associated with frequency of bowel movement <3/week (odds ratio [OR] = 0.376, 95% confidence interval [CI]: 0.156-0.904, P = 0.029) or Bristol Stool Form Scale (BSFS) type 3 (OR = 0.401, 95% CI: 0.170-0.946, P = 0.037).

CONCLUSIONS

Our study showed that CC patients with BSFS type3 were not satisfied with constipation treatment. In general, BSFS types 3-5 are defined as normal stools. Therefore, BSFS type 3 may be set as a treatment goal even though the patient is not satisfied. The pathophysiology of CC differs by region and patient background. Therefore, parameters used to define successful treatment will be different by patient or region. We should reconsider the positioning of BSFS type 3 to improve treatment satisfaction for CC.

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.

Global burden of irritable bowel syndrome: trends, predictions and risk factors

Irritable bowel syndrome (IBS) is one of the most common disorders of gut-brain interaction worldwide, defined according to patterns of gastrointestinal symptoms as described by the Rome diagnostic criteria. However, these criteria, developed with reference to research conducted largely in Western populations, might be limited in their applicability to other countries and cultures. Epidemiological data show a wide variation in the prevalence of IBS globally and more rigorous studies are needed to accurately determine any differences that might exist between countries as well as the potential explanations. The effects of IBS on the individual, in terms of their quality of life, and on health-care delivery and society, in terms of economic costs, are considerable. Although the magnitude of these effects seems to be comparable between nations, their precise nature can vary based on the existence of societal and cultural differences. The pathophysiology of IBS is complex and incompletely understood; genetics, diet and the gut microbiome are all recognized risk factors, but the part they play might be influenced by geography and culture, and hence their relative importance might vary between countries. This Review aims to provide an overview of the burden of IBS in a global context, to discuss future implications for the care of people with IBS worldwide, and to identify key areas for further research.

Probiotic treatment induced change of inflammation related metabolites in IBS-D patients/double-blind, randomized, placebo-controlled trial

There have been many studies suggesting that probiotics are effective in patients with diarrhea-predominant irritable bowel syndrome (IBS-D). However, its mechanism of action as well as prediction of response is still to be elucidated. In the present study, to find out metabolomic characteristics of probiotic effect in IBS-D, we compared IBS symptom changes and metabolomic characteristics in the subjects' urine samples between multi-strain probiotics (one strain of Lactobacillus sp. and four strains of Bifidobacterium sp.) group (n = 32) and placebo group (n = 31). After 8 weeks' administration (3 times/day), dissatisfaction in bowel habits and stool frequencies were significantly improved. Also, probiotics group had significantly changed seven metabolites including palmitic acid methyl ester (PAME) and 4,6-dihydroxyquinoline, 4-(2-aminophenyl)-2,4-dioxobutanoic acid (DOBA). According to IBS-SSS and IBS-QoL questionnaires, IBS-SSS responders showed higher PAME levels and IBS-QoL responders showed lower DOBA levels. This suggests potential role of these metabolites as a biomarker to predict probiotics effect in IBS-D patients.

Targeting the gut microbiota for the treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder that affects an estimated 11% of people across the world. IBS patients are one of the largest subgroups seen in gastroenterology clinics, exhibit a lesser quality of life, and take greater use of the healthcare system. The exact etiology of IBS remains uncertain. Alterations in the gut microbiome may characterize apotential mechanism in the pathogenesis of IBS. This hypothesis is paralleled by rodent models in which manipulation of the gut microbiota leads to disturbed physiological functions along the brain-gut axis. Recent research in IBS treatments has redirected its focus towards gu microbiome based therapeutics. In this review, we discuss potential roles of enteric bacteria in the pathogenesis of IBS and its comorbidities. We then explore the manipulation of the enteric microbiota by prebiotics, probiotics, antibiotics, dietary changes, and fecal microbiota transfer. We also discuss the positive and negative effects of these therapeutics on IBS symptoms.

Nature and specificity of altered cognitive functioning in IBS

BACKGROUND

It is unknown whether cognitive dysfunction found in patients with irritable bowel syndrome (IBS) was attributable to the different subtypes, ongoing pathophysiological processes, trait characteristics, or psychiatric comorbidity.

METHODS

Forty Rome-III patients with IBS (20 diarrhea-predominant [IBS-D] and 20 constipation-predominant [IBS-C]) and 40 age-, sex-, education-matched healthy controls were systematically recruited and compared on their cognitive function with continuous performance test (CPT), Wisconsin Card Sorting Test (WCST) and emotional Stroop test. Beck Anxiety Inventory (BAI), Beck Depression Inventory-II (BDI-II), Patient Health Questionnaire-15 (PHQ-15) and a structured bowel symptom questionnaire were performed to measure anxiety, depressive, somatization, and bowel symptoms, respectively. Psychiatric diagnoses were ascertained with SCID-I (Structured Clinical Interview for DSM-IV Axis I Disorders).

KEY RESULTS

Patients with IBS showed significantly increased standard deviation of reaction time (SDRT) (P = .003) on CPT, increased failure to maintain set (FMS) (P=.002), and percentage of perseverative errors (P = .003) on WCST. SDRT did not correlate with illness chronicity or bowel symptoms. FMS correlated with bowel symptom severity. In logistic regression models controlled for BAI, BDI-II, and PHQ-15, SDRT (AOR = 1.08, P = .025), but not FMS (P = .25) or percentage of perseverative errors (P = .24), significantly differentiated IBS from controls. Cognitive function was not significantly different between IBS-C and IBS-D (P > .05), or between pure IBS (n = 22) and IBS with generalized anxiety disorder (GAD) (n = 17) (P > .05).

CONCLUSIONS & INFERENCES

Patients with IBS showed attentional and executive function impairment irrespective of subtypes but otherwise heterogeneous in terms of its state-trait correlations and overlap with anxiety comorbidity.

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.

Second Asian Consensus on Irritable Bowel Syndrome

BACKGROUND/AIMS

There has been major progress in our understanding of the irritable bowel syndrome (IBS), and novel treatment classes have emerged. The Rome IV guidelines were published in 2016 and together with the growing body of Asian data on IBS, we felt it is timely to update the Asian IBS Consensus.

METHODS

Key opinion leaders from Asian countries were organized into 4 teams to review 4 themes: symptoms and epidemiology, pathophysiology, diagnosis and investigations, and lifestyle modifications and treatments. The consensus development process was carried out by using a modified Delphi method.

RESULTS

Thirty-seven statements were developed. Asian data substantiate the current global viewpoint that IBS is a disorder of gut-brain interaction. Socio-cultural and environmental factors in Asia appear to influence the greater overlap between IBS and upper gastrointestinal symptoms. New classes of treatments comprising low fermentable oligo-, di-, monosacharides, and polyols diet, probiotics, non-absorbable antibiotics, and secretagogues have good evidence base for their efficacy.

CONCLUSIONS

Our consensus is that all patients with functional gastrointestinal disorders should be evaluated comprehensively with a view to holistic management. Physicians should be encouraged to take a positive attitude to the treatment outcomes for IBS patients.

An open-label randomized pragmatic non-inferiority pilot trial to compare the effectiveness of Dysentery compound with individualized homeopathic medicines in irritable bowel syndrome

Background Irritable Bowel Syndrome (IBS) is a prevalent gastro-intestinal disorder characterized by recurrent abdominal pain, bloating, altered bowel function and myriad of gastro-intestinal symptoms. Dysentery compound (DC), a 'bowel nosode', is one of the homeopathic medicines to treat IBS, but remained under-researched. We hypothesized that DC would be non-inferior to individualized homeopathy (IH) in treatment of IBS. Method An open, randomized (1:1), parallel arms, pragmatic, non-inferiority, pilot trial was conducted to compare the effectiveness of DC with IH medicines in 60 IBS patients. IBS Quality of Life (IBS-QOL) questionnaire was used as the outcome measure; assessed at baseline and after 3 months. Comparative analysis was carried out on the primary outcome to detect non-inferiority by one-tailed t test at alpha=5% with a prefixed margin (Δ) of 1.0 based on assumption. Results Six subjects dropped out. Groups were comparable at baseline (all p>0.01). Though intra-group changes were higher favoring IH over DC, group differences were statistically non-significant (all p>0.01). Non-inferiority was not demonstrated by DC against IH over 3 months (mean difference= -3.3, SE=5.2, lower 95% confidence limit -11.9, t= -0.453, p=0.674). No adverse events were reported from either group. Conclusion Non-inferiority of DC against IH in treatment of IBS was not demonstrated though it appeared as safe; still, being a pilot trial, no definite conclusion could be drawn. Further exploration of both efficacy and effectiveness of either of the therapies is necessary by adequately powered trials and independent replications. Trial registration: CTRI/2017/05/008480; UTN: U1111-1196-1004.

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

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

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.

Serotonin-estrogen interactions: What can we learn from pregnancy?

We have reviewed the scientific literature related to four diseases in which to serotonin (5-HT) is involved in the etiology, herein named 5-HT-linked diseases, and whose prevalence is influenced by estrogenic status: depression, migraine, irritable bowel syndrome and eating disorders. These diseases all have in common a sex-dimorphic prevalence, with women more frequently affected than men. The co-occurrence between these 5-HT-linked diseases suggests that they have common physiopathological mechanisms. In most 5-HT-linked diseases (except for anorexia nervosa and irritable bowel syndrome), a decrease in the serotonergic tone is observed and estrogens are thought to contribute to the improvement of symptoms by stimulating the serotonergic system. Human pregnancy is characterized by a unique 5-HT and estrogen synthesis by the placenta. Pregnancy-specific disorders, such as hyperemesis gravidarum, gestational diabetes mellitus and pre-eclampsia, are associated with a hyperserotonergic state and decreased estrogen levels. Fetal programming of 5-HT-linked diseases is a complex phenomenon that involves notably fetal-sex differences, which suggest the implication of sex steroids. From a mechanistic point of view, we hypothesize that estrogens regulate the serotonergic system, resulting in a protective effect against 5-HT-linked diseases, but that, in turn, 5-HT affects estrogen synthesis in an attempt to retrieve homeostasis. These two processes (5-HT and estrogen biosynthesis) are crucial for successful pregnancy outcomes, and thus, a disruption of this 5-HT-estrogen relationship may explain pregnancy-specific pathologies or pregnancy complications associated with 5-HT-linked diseases.

A prospective study on incidence, risk factors, and validation of a risk score for post-infection irritable bowel syndrome in coastal eastern India

BACKGROUND AND AIM

Post-infection irritable bowel syndrome (PI-IBS) can occur following acute gastroenteritis (AGE). This study was designed to evaluate the incidence and risk factors of PI-IBS following AGE and to validate a PI-IBS risk score.

METHODS

This prospective study was performed between September 2014 and October 2016 on AGE patients by documenting their AGE severity and following up after 3 and 6 months to study the development of IBS (ROME III criteria). The risk score was calculated for all the subjects, and its discrimination ability was tested.

RESULTS

Out of 136 hospitalized AGE patients, 35 developed PI-IBS after 6 months. The factors associated with PI-IBS were younger age, longer duration of AGE, anxiety, depression, abdominal pain, bloody stool, vomiting, fever, family history of IBS, and positive stool culture (univariate analysis); however, on multivariate analysis, younger age (adjusted odds ratio [AOR] 0.5; p 0.03), prolonged duration of AGE (AOR 8.6; p 0.01), and abdominal cramps (AOR 2.1; p 0.02) were the independent factors influencing its occurrence. PI-IBS occurred even after infection with Vibrio cholerae. The PI-IBS risk score was significantly higher in patients who developed PI-IBS (72.4 ± 14.48 vs. 31.56 ± 20.4, p-value < 0.001); score > 50 had a sensitivity and specificity of 91.4% and 84.2%, respectively.

CONCLUSION

One fourth of AGE patients developed PI-IBS after 6 months. Factors influencing its development were younger age, long duration of AGE, and abdominal pain. The PI-IBS risk score had good predictive accuracy in our population.

Positive endoscopic and ultrasonographic findings in patients with symptom-diagnosed functional gastrointestinal disorder: Data from a Chinese cross-sectional study

OBJECTIVE

Few studies have systematically assessed symptom-based diagnoses of functional gastrointestinal disorders (FGID) in China. This study aimed to evaluate the positive endoscopic and ultrasonographic findings in patients with symptom-based FGID.

METHODS

Adult patients with gastrointestinal symptoms but not red flag symptoms who were empirically diagnosed with FGID underwent an upper or lower gastrointestinal endoscopy. An abdominal ultrasonography was also performed to screen for potential organic diseases. Patients' data were collected and the Rome III questionnaire was used for symptom-based assessment.

RESULTS

Positive endoscopic and ultrasonographic findings were detected in 31.8%, 26.2% and 9.9% of patients with esophageal, gastroduodenal and intestinal disorders, respectively. Among patients diagnosed with FGID using the questionnaire, the rates of positive endoscopic and ultrasonographic findings were higher in patients with upper gastrointestinal symptoms than in those with lower gastrointestinal symptoms. Moreover, patients elder than 34.5 years with upper gastrointestinal symptoms and those elder than 47.5 years with lower gastrointestinal symptoms were more likely to have positive endoscopic and ultrasonographic findings.

CONCLUSIONS

The Rome III questionnaire is a valuable diagnostic tool for screening FGID in China. However, the rates of positive endoscopic and ultrasonographic findings vary depending on the location of symptoms. Endoscopy and ultrasonography have irreplaceable value, especially for investigating upper gastrointestinal symptoms.

Cultural Factors Influencing Functional Gastrointestinal Disorders in the East

Culture forms an integral aspect of environmental factors which influences disease presentation and clinical outcomes in functionalgastrointestinal disorders (FGIDs). In this review, the role of culture in FGIDs in the East is briefly explored with regards to symptompresentation and diagnostic issues, lifestyle and cultural habits, epidemiology, and healthcare seeking behavior. In both functionaldyspepsia and irritable bowel syndrome, symptom presentation and disease sub-typing in Asians are known to differ from their Western counterparts, possibly relating to cultural dietary practices and from cultural perception of symptoms. Dietary patterns, together with defecating practices are explored as factors contributing to a lower prevalence of constipation in the East. An urban-rural difference in the prevalence of FGIDs in Asia is attributed to a change in dietary patterns in rapidly developing urban communities, together with an increased level of psychological morbidity. Lastly, cultural attitudes towards traditional/local remedies, variation in healthcare systems, anxiety regarding organic disease, and religious practices have been shown to influence healthcare seeking behavior among FGID patients in the East.

Tong-Xie-Yao-Fang Regulates 5-HT Level in Diarrhea Predominant Irritable Bowel Syndrome Through Gut Microbiota Modulation

Tong-Xie-Yao-Fang (TXYF) has been widely used for the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D) in traditional Chinese medicine. However, its mechanism of action in the treatment of IBS-D remains to be fully understood. Recent reports have shown that Clostridium species in the gut can induce 5-HT production in the colon, which then contributes to IBS-D. Due to the wide use of TXYF in the clinical treatment of IBS-D and the close relationship between gut microbiota and IBS-D, we hypothesize that TXYF treats IBS-D by modulating gut microbiota and regulating colonic 5-HT levels. In this study, variation analysis of 16S rRNA was conducted to evaluate changes in the distribution of gut microbiota in IBS-D model rats after TXYF treatment. Moreover, we investigated whether TXYF could affect colonic 5-HT levels in IBS-D model rats. We then performed fecal transplantation experiments to confirm the effects of TXYF on gut microbiota and 5-HT levels. We found that TXYF treatment can ameliorate IBS-D and regulate 5-HT levels in colon tissue homogenates. TXYF treatment also affected the diversity of gut microbiota and altered the relative abundance of Akkermansia and Clostridium sensu stricto 1 in gut flora populations. Finally, we showed that fecal transplantation from TXYF-treated rats could relieve IBS-D and regulate 5-HT levels in colon tissue homogenates. In conclusion, the present study demonstrates that TXYF treatment diminishes colonic 5-HT levels and alleviates the symptoms of IBS-D by favorably affecting microbiota levels in gut flora communities.

Long-Term Gastrointestinal Consequences are Frequent Following Sporadic Acute Infectious Diarrhea in a Tropical Country: A Prospective Cohort Study

BACKGROUND

Postinfection irritable bowel syndrome (PI-IBS) and functional dyspepsia (PI-FD), though reported from the temperate countries, have not been studied in the tropics; PI-malabsorption syndrome (MAS), which mimics PI-IBS, is reported from the tropics. No report till date on PI-IBS excluded PI-MAS. We studied: (i) the frequency of continuing bowel dysfunction after acute gastroenteritis (AG), (ii) its predictors, and (iii) PI-MAS among patients with PI-IBS.

METHODS

345 consecutive subjects each, with AG and age- and gender-matched healthy controls were followed up 3-monthly for 12 months using a translated-validated questionnaire and functional gastrointestinal disorders (FGIDs) were diagnosed by Rome III criteria. Symptom duration >3 months but <6 months was diagnosed as chronic bowel dysfunction (CBD) and dyspeptic symptoms, respectively. MAS was diagnosed if 2/3 tests (D-xylose H₂ breath test, Sudan III-stained stool microscopy, and duodenal histology) were abnormal. Fecal microbiological studies were performed in 245/345 (71%) patients.

RESULTS

AG patients more often developed PI-IBS and PI-FD than controls (16.5 vs. 2.6% and 7.4 vs. 0.6%, respectively; p<0.001). Presence of FD was a risk factor for PI-IBS and IBS for PI-FD. On multivariate analysis, dyspeptic symptoms, CBD, and weight loss were the risk factors for PI-FGIDs. The frequency of PI-IBS following Vibrio cholera and other bacterial infection was comparable. Malabsorption was present among 2/23 (9%) patients with PI-IBS.

CONCLUSION

FGIDs are common after AG; dyspeptic symptoms, CBD, and weight loss were risk factors for PI-FGIDs. Vibrio cholerae infection caused PI-FGID, which was never reported. About 9 % patients fulfilling the criteria for PI-IBS had PI-MAS.

How the Change in IBS Criteria From Rome III to Rome IV Impacts on Clinical Characteristics and Key Pathophysiological Factors

OBJECTIVES

The diagnostic criteria for irritable bowel syndrome (IBS) have recently been updated from Rome III to Rome IV. Whereas in Rome III a diagnosis of IBS entailed chronic abdominal pain or discomfort at least 3 days per month, in Rome IV the term discomfort has been removed and the frequency of abdominal pain increased to at least 1 day per week. We examined how this change in IBS criteria impacts on clinical characteristics and pathophysiological factors.

METHODS

A total of 542 Swedish subjects with Rome III IBS completed a baseline questionnaire enquiring for the number of abdominal pain days in the last 10 days; this was subsequently used as a surrogate marker to identify Rome IV IBS, in that (a) those with 0 or 1 day of pain were classed as Rome IV-negative, and (b) those with ≥2 days of pain were classed as Rome IV-positive. Comparisons were made between Rome IV-positive and -negative IBS groups for demographics, IBS subtype, gastrointestinal and psychological symptoms, somatisation, fatigue, disease-specific quality of life, rectal sensitivity, and oro-anal transit time.

RESULTS

Overall, 85% of Rome III IBS patients fulfilled the Rome IV criteria for IBS, but 15% did not. Rome IV-positive subjects were significantly more likely to be female, have poorer quality of life, greater pain severity, bloating, somatisation, fatigue, and rectal sensitivity than Rome IV-negative subjects. There were no differences in severity of anxiety or depression, IBS subtypes, bowel habit dissatisfaction, or oro-anal transit time. Finally, increasing number of pain days correlated positively with symptoms and visceral hypersensitivity.

CONCLUSIONS

Most Rome III-positive IBS patients seeking healthcare fulfil the Rome IV IBS criteria. They constitute a more severe group than those who lose their IBS diagnosis.

Rome Foundation-Asian working team report: Asian functional gastrointestinal disorder symptom clusters

OBJECTIVE

Functional gastrointestinal disorders (FGIDs) are diagnosed by the presence of a characteristic set of symptoms. However, the current criteria-based diagnostic approach is to some extent subjective and largely derived from observations in English-speaking Western patients. We aimed to identify latent symptom clusters in Asian patients with FGID.

DESIGN

1805 consecutive unselected patients with FGID who presented for primary or secondary care to 11 centres across Asia completed a cultural and linguistic adaptation of the Rome III Diagnostic Questionnaire that was translated to the local languages. Principal components factor analysis with varimax rotation was used to identify symptom clusters.

RESULTS

Nine symptom clusters were identified, consisting of two oesophageal factors (F6: globus, odynophagia and dysphagia; F9: chest pain and heartburn), two gastroduodenal factors (F5: bloating, fullness, belching and flatulence; F8 regurgitation, nausea and vomiting), three bowel factors (F2: abdominal pain and diarrhoea; F3: meal-related bowel symptoms; F7: upper abdominal pain and constipation) and two anorectal factors (F1: anorectal pain and constipation; F4: diarrhoea, urgency and incontinence).

CONCLUSION

We found that the broad categorisation used both in clinical practice and in the Rome system, that is, broad anatomical divisions, and certain diagnoses with long historical records, that is, IBS with diarrhoea, and chronic constipation, are still valid in our Asian societies. In addition, we found a bowel symptom cluster with meal trigger and a gas cluster that suggests a different emphasis in our populations. Future studies to compare a non-Asian cohort and to match to putative pathophysiology will help to verify our findings.

Association of mitochondrial displacement loop polymorphisms with diarrhea-predominant irritable bowel syndrome: A preliminary study

OBJECTIVES

To investigate whether single nucleotide polymorphisms (SNPs) in the mitochondrial displacement loop (D-loop) were associated with irritable bowel syndrome (IBS).

METHODS

Altogether 40 participants were recruited and classified into three groups, including 20 that fulfilled the Rome III criteria for diarrhea-predominant IBS (IBS-D), 10 with constipation-predominant IBS (IBS-C), and 10 healthy volunteers (controls). DNA was extracted from biopsy specimens of the colon obtained during routine colonoscopies. The mitochondrial D-loop was sequenced and variants were identified in comparison with the reference sequence from GenBank. We searched GenBank and MITOMAP to determine whether a variant could be considered an SNP.

RESULTS

No significant differences in sex, age and body mass index were found among the three groups. The average numbers of SNPs in the IBS-D, IBS-C and control groups were 12.2 ± 2.7, 9.8 ± 1.8 and 9.9 ± 2.1, respectively. The frequency of SNPs was significantly higher in the IBS-D group than in the IBS-C group and controls (P < 0.05). No significant difference was found between the latter two groups. Each SNP was compared among the three groups and the frequency of 199C was found to be significantly higher in the control group than in the IBS-D group (P = 0.03), but no significant difference in its frequency was found between the IBS-C group and controls.

CONCLUSIONS

Patients with IBS-D have a higher incidence of SNPs in the mitochondrial D-loop than controls. The genotype 199C may be associated with a lower risk of IBS-D.

Cross cultural comparison of constipation profiles at tertiary care centers between India and USA

BACKGROUND

Despite potential differences in patient perception of chronic constipation (CC) in geographically and culturally distinct regions, head-to-head studies comparing the clinical profile, constipation severity, impact on quality of life (QOL) and economic impact are lacking.

METHODS

We conducted a cross-sectional cohort study of patients presenting with CC to tertiary care centers in the USA and India. Standardized instruments were used to assess constipation subtype, disease severity, disease-specific QOL, somatization, and psychiatric comorbidities. We used multivariable linear regression to determine the predictors of QOL and number of healthcare visits.

KEY RESULTS

Sixty-six and 98 patients with CC were enrolled in the USA and India, respectively. Indian patients with CC had significantly more frequent bowel movements/week compared to their USA counterparts (Median 5 vs 3, P < .0001). The proportion of patients with Bristol stool form scale type 1 and 2 was significantly higher in the USA compared to India (65.5% vs 48%, P = .04). Higher depression score (P = .001), more severe constipation symptoms (P = .001) and site of the study being USA (P = .008) independently predicted worse QOL. Indian patients (P < .001) and worse QOL (P = .02) were independent predictors of number of healthcare visits in the last 12 months.

CONCLUSIONS AND INFERENCES

Indian patients with CC have more frequent and softer bowel movements compared to those in the USA suggesting significant differences in perception of CC in different geographic and cultural settings. QOL and economic impact related to constipation varies with geographic/cultural setting irrespective of other clinical and psychosomatic features.

Breath Hydrogen Testing in East and Southeast Asia

Breath hydrogen tests are popular, noninvasive tests for the assessment of carbohydrate fermentation in patients with irritable bowel syndrome (IBS) and functional dyspepsia (FD). There is limited information regarding the utility of breath hydrogen and methane tests in IBS and FD patients in East and Southeast Asia. This review aims to summarize current literature about common indications of breath testing in this region, the genesis of functional gastrointestinal symptoms by provocative breath testing and provide suggestions for correct use. The most common testing indication is the assessment of lactose intolerance, followed by small intestinal bacterial overgrowth (SIBO) and differentiation of intestinal gas profiles in research setting. Studies in this region not only documented a high prevalence of lactose malabsorption but a population, both healthy and IBS, that is highly symptomatic to typical lactose intakes. Breath hydrogen assessment of other fermentable carbohydrates (FODMAPs) are fairly uncommon, whereas methane breath testing is almost nonexistent. Cumulative hydrogen production following lactulose was also not excessive in IBS patients compared with controls. The evidence however, for the detection of SIBO suggests limited reliability in the use of lactulose or glucose breath testing alone and inconclusive data on its correlation with symptoms. Conversely, little has been carried out in FD. In conclusion, breath testing should be limited in the predicting patients with SIBO for directing clinical management but can be considered in the objective assessment of lactose malabsorption within a low FODMAP diet. Recommendations to improve the interpretation of breath testing in research were also provided.

Dietary practices and FODMAPs in South Asia: Applicability of the low FODMAP diet to patients with irritable bowel syndrome

The low Fermentable Oligosaccharides, Disaccharides, and Monosaccharides And Polyols (FODMAP) diet has been described, evaluated, and found efficacious for the treatment of patients with irritable bowel syndrome primarily in Western countries. The aim of this review was to address the applicability of this diet to South Asia. The high prevalence of irritable bowel syndrome in South Asia and its associated effects of quality of life and economics warrant the introduction of efficacious therapies. The considerable heterogeneity of dietary patterns and methods of food preparation across South Asian countries and a paucity of food analysis limit precision in defining foods that are high or low in FODMAPs. Spices and condiments are commonly consumed and mostly have a low FODMAP content. However, major high FODMAP sources are frequently used and include onion, garlic, shallots, legumes/pulses, and wheat-based products, as well as coconut and milk products, offering an opportunity for dietary management to reduce the symptom load. The feasibility of instituting a restrictive diet in which foods with a high FODMAP content are replaced by foods low in FODMAPs must be addressed as a substantial proportion of the nutritional intake including energy, proteins, and micronutrients, is often obtained from FODMAP-rich food. Furthermore, limited knowledge of health professionals together with a paucity of dietitians further challenge the practicality of introducing the diet. Thus, while the use of the low FODMAP diet in South Asia may be more limited than in westernized countries, it does offer potential therapeutic opportunities, the efficacy, and impact of which require further investigation.

Irritable bowel syndrome in Asia: Pathogenesis, natural history, epidemiology, and management

Historically, the epidemiology of gastrointestinal diseases in Asia was different from that in Western countries. Early studies suggested a low prevalence of irritable bowel syndrome (IBS) in Asia. As the diagnosis of IBS is symptom-based and as symptom perception, expression, and interpretation are influenced by sociocultural perspectives including language, the presentation of IBS is expected to vary in different communities. Furthermore, the pathogenesis is multifactorial with psychosocial (stress, illness, behavior, and diet) and biological (infection, gut microbiota, and immune activation) variables interacting, and so, the present study can anticipate that the development of IBS will vary in different environments. In recognition of this aspect of functional gastrointestinal disorders, the recently published Rome IV documents have provided greater focus on cross-cultural factors. In this review, the present study seeks to highlight Asian perspectives by identifying historical trends and recent publications from the region and comparing these with the observations from Western societies.

The role of the microbiome and the use of probiotics in gastrointestinal disorders in adults in the Asia-Pacific region - background and recommendations of a regional consensus meeting

The Asia-Pacific region is diverse, with regard to ethnicity, culture, and economic development incorporating some of the world's least and most developed nations. Gastrointestinal diseases are common in the Asia-Pacific region, and their prevalence, presentation, and management vary considerably within the region. There is growing evidence for an important role for the human gut microbiota in gastrointestinal health. As a consequence, geographic variations in the composition of the gut microbiota may contribute to variations in both the prevalence and response to therapy of specific diseases. Probiotics have been proposed as a valuable option in the prevention and treatment of a number of gastrointestinal illnesses, but the quality of available evidence to support their efficacy is variable. A meeting of international experts in adult and pediatric gastroenterology was held at the Sorbonne University, Paris, France, on April 11 and 12, 2016, to discuss current evidence supporting the use of probiotics in gastrointestinal disorders in the Asia-Pacific region. This article provides an overview of the discussions held at this meeting and recommends the formation of an Asia-Pacific Consortium on Gut Microbiota similar to those established in Europe and North America.

New therapies in Irritable Bowel Syndrome: what works and when

PURPOSE OF REVIEW

The purpose of this review is to examine the evidence supporting the use of recently developed pharmacological treatments for IBS together with new evidence supporting more traditional therapies in order to understand where the new agents are best used in the treatment pathway.

RECENT FINDINGS

There is evidence to support the use of traditional treatments such as antispasmodics, antidepressants and dietary alteration in IBS. New therapeutic agents such as Linaclotide, Lubiprostone, Plecanatide, Rifaxamin and Eluxadoline are all more effective than placebo in treating symptoms of IBS with Tenapanor being a promising new agent. The majority of patients, however, treated with these medications remain symptomatic and they are not suitable for use in all patients.

SUMMARY

Traditional treatments such as antispasmodics, antidepressants, dietary and lifestyle modifications retain their importance in the treatment of IBS with the newer agents to be considered wherever these treatments are ineffective or poorly tolerated.

Indian consensus on chronic constipation in adults: A joint position statement of the Indian Motility and Functional Diseases Association and the Indian Society of Gastroenterology

The Indian Motility and Functional Diseases Association and the Indian Society of Gastroenterology developed this evidence-based practice guideline for management of chronic constipation. A modified Delphi process was used to develop this consensus containing 29 statements, which were generated by electronic voting iteration as well as face to face meeting and review of the supporting literature primarily from India. These statements include 9 on epidemiology, clinical presentation, and diagnostic criteria; 8 on pathophysiology; and the remaining 12 on investigations and treatment. When the proportion of those who voted either to accept completely or with minor reservation was 80% or higher, the statement was regarded as accepted. The members of the consensus team believe that this would be useful for teaching, clinical practice, and research on chronic constipation in India and in other countries with similar spectrum of the disorders.

Enteroendocrine, Musashi 1 and neurogenin 3 cells in the large intestine of Thai and Norwegian patients with irritable bowel syndrome

OBJECTIVES

The prevalence, gender distribution and clinical presentation of IBS differ between Asian and Western countries. This study aimed at studying and comparing enteroendocrine, Musashi 1 (Msi 1) and neurogenin 3 (neurog 3) cells in Thai and Norwegian IBS patients.

MATERIAL AND METHODS

Thirty Thai and 61 Norwegian IBS patients as well as 20 Thai and 24 Norwegian controls were included. Biopsy samples were taken from each of the sigmoid colon and the rectum during a standard colonoscopy. The samples were immunostained for serotonin, peptide YY, oxyntomodulin, pancreatic polypeptide, somatostatin, Msi 1 and neurog 3. The densities of immunoreactive cells were determined with computerized image analysis.

RESULTS

The densities of several enteroendocrine cell types were altered in both the colon and rectum of both Thai and Norwegian IBS patients. Some of these changes were similar in Thai and Norwegian IBS patients, while others differed.

CONCLUSIONS

The findings of abnormal densities of the enteroendocrine cells in Thai patients support the notion that enteroendocrine cells are involved in the pathophysiology of IBS. The present observations highlight that IBS differs in Asian and Western countries, and show that the changes in large-intestine enteroendocrine cells in Thai and Norwegian IBS patients might be caused by different mechanisms.

Epidemiological and clinical perspectives on irritable bowel syndrome in India, Bangladesh and Malaysia: A review

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder, common in clinic and in the community. It has a significant impact on both society and patients' quality of life. The epidemiology, clinical presentation, and management of IBS may vary in different geographical regions due to differences in diet, gastrointestinal infection, socio-cultural and psycho-social factors, religious and illness beliefs, symptom perception and reporting. Although previous reviews and consensus reports on IBS in Asia have been published, Asia is quite diverse socio-demographically. In this context, India, Bangladesh and Malaysia share some similarities, including: (1) large proportion of the population living in rural areas; (2) rapid development and associated lifestyle changes in urban areas; and (3) dietary, cultural and religious practices. The present review explores the clinical and epidemiological data on IBS from these three major nations in South and South-East Asia. In-depth review of the literature revealed important differences between IBS in the East, as revealed by studies from these three countries, and the West; these include a predominantly rural profile, differences in bowel habit and symptom profile, raising concern with regards to diagnostic criteria and subtyping of IBS, higher dietary fiber consumption, frequent lactose malabsorption, parasitosis, and possible overlap between post-infectious IBS and tropical sprue. Moreover, the current perception on difference in prevalence of the disorder in these countries, as compared to the West, might be related to variation in survey methods.

Chromogranin A cell density in the large intestine of Asian and European patients with irritable bowel syndrome

OBJECTIVE

Patients with irritable bowel syndrome (IBS) in Asia show distinctive differences from those in the western world. The gastrointestinal endocrine cells appear to play an important role in the pathophysiology of IBS. The present study aimed at studying the density of chromogranin A (CgA) cells in the large intestine of Thai and Norwegian IBS patients.

METHODS

Thirty Thai IBS patients and 20 control subjects, and 47 Norwegian IBS patients and 20 control subjects were included. A standard colonoscopy was performed in both the patients and controls, and biopsy samples were taken from the colon and the rectum. The biopsy samples were stained with hematoxylin-eosin and immunostained for CgA. The density of CgA cells was determined by computerized image analysis.

RESULTS

In the colon and rectum, the CgA cell densities were far higher in both IBS and healthy Thai subjects than in Norwegians. The colonic CgA cell density was lower in Norwegian IBS patients than in controls, but did not differ between Thai IBS patients and controls. In the rectum, the CgA cell densities in both Thai and Norwegian patients did not differ from those of controls.

CONCLUSIONS

The higher densities of CgA cells in Thai subjects than Norwegians may be explained by a higher exposure to infections at childhood and the development of a broad immune tolerance, by differences in the intestinal microbiota, and/or differing diet habits. The normal CgA cell density in Thai IBS patients in contrast to that of Norwegians may be due to differences in pathophysiology.

Post-Infectious Irritable Bowel Syndrome

PURPOSE OF REVIEW

Post-infectious irritable bowel syndrome (PI-IBS) is characterized by persistent abdominal pain and diarrhea, typically following an episode of infectious gastroenteritis. The mechanisms that underlie IBS-D remain elusive, but PI-IBS provides a mechanistic model of this disorder. This review provides an up-to-date appraisal of the pathophysiology, clinical features, and management approaches for PI-IBS.

RECENT FINDINGS

Disordered immune reactions and release of cytokines with resultant gut inflammation and dysfunction appear to be key features of PI-IBS. Disordered brain-gut-microbiota interactions, type of infecting agent, and host-genetic susceptibility are risk factors but also are reasons for the varying spectrum of clinical severity. Although prognosis is generally good, symptoms and inflammation may persist for a long time. Symptomatic relief with antidiarrheals, antispasmodics, 5HT₃ antagonists, mesalamine, probiotics, and low-dose antidepressants remain the primary approaches, but in some difficult cases, a combination of drugs that target the pathophysiology may be helpful. PI-IBS has many overlapping features with IBS-D and shares similar pathophysiology and management approaches.