Gender differences in irritable bowel syndrome

Interacting influences of gender and chronic pain status on parasympathetically mediated heart rate variability in adolescents and young adults

Considerable research links chronic pain to autonomic nervous system (ANS) dysfunction, specifically low heart rate variability (HRV) mediated by reduced parasympathetic activity. However, little is known about factors that influence ANS function in chronic pain. The ANS is the primary pathway for brain-gut communication, making it of particular interest in gastrointestinal disorders, such as irritable bowel syndrome, characterized by functional abdominal pain (FAP). We evaluated the relation of sex, pain severity, and psychological stress to ANS function in adolescents/young adults from a database of pediatric FAP and control participants enrolled 8 years earlier in a prospective study of pain. At follow-up in adolescence/young adulthood (Mean age = 19.46, SD = 3.48), we classified participants as Pain-Remit (n = 130), Pain-Persist (n = 96), and pain-free controls (n = 123). We recorded electrocardiogram data at rest and during laboratory stressors. Results demonstrated significantly lower HRV in Pain-Persist females compared with Pain-Remit females, female controls, and all males regardless of pain category. Spectral analysis of electrocardiogram showed that Pain-Persist females had reduced power in the high frequency domain of cardiac activity, ie, reduced parasympathetic "braking" of sympathetic activity, both at rest and during stress. Pain-Remit females exhibited levels of autonomic imbalance intermediate between those of females with persistent FAP and all other participants. Parasympathetically mediated low HRV in young women with persistent FAP may reflect a peripheral mechanism (eg, gut dysfunction) or a central nervous system mechanism (eg, pain amplification or poor emotion self-regulation) involving prolonged sympathetic activation.

Trends of Cholecystectomies for Presumed Biliary Dyskinesia in Children in the United States

BACKGROUND

Biliary dyskinesia (BD) is a controversial clinical entity. Standardized diagnostic test and management guidelines are lacking in children. Published data suggest that long-term outcomes of surgical and medical management are similar. We sought to determine national population-based trends of cholecystectomies performed in children for BD and associated healthcare expenditure in the United States during a 10-year period.

METHODS

Using Nationwide Inpatient Sample and the International Classification of Diseases, the 9th revision clinical modification codes, we identified children who had a cholecystectomy for BD from 2002 to 2011 in the United States.

RESULTS

A total of 66,380 cholecystectomies were identified as primary procedural diagnosis using weighted analysis from 2002 to 2011 in children. BD was the primary indication for cholecystectomy in 6674 (10.8%) of the patients. During the study period, the number of cholecystectomies performed for BD in children increased from 6.6% in 2002 to 10.6% in 2011, and a majority were adolescent white females. The annual health care expenditure for surgical management of BD for children in the US was estimated to almost $16 million/year.

CONCLUSIONS

Despite lack of standardized diagnostic criteria and variable outcomes of surgical intervention reported in pediatric literature, cholecystectomies are commonly performed for children with BD in the United States. Consensus guidelines for the diagnosis and management of this controversial disorder in children are needed.

Word-of-Mouth Innovation: Hypothesis Generation for Supplement Repurposing based on Consumer Reviews

Dietary supplements remain a relatively underexplored source for drug repurposing. A systematic approach to soliciting responses from a large consumer population is desirable to speed up innovation. We tested a workflow that mines unexpected benefits of dietary supplements from massive consumer reviews. A (non-exhaustive) list of regular expressions was used to screen over 2 million reviews on health and personal care products. The matched reviews were manually analyzed, and one supplement-disease pair was linked to biological databases for enriching the hypothesized association. The regular expressions found 169 candidate reviews, of which 45.6% described unexpected benefits of certain dietary supplements. The manual analysis showed some of the supplement-disease associations to be novel or in agreement with evidence published later in the literature. The hypothesis enrichment was able to identify meaningful function similarity between the supplement and the disease. The results demonstrated value of the workflow in identifying candidates for supplement repurposing.

Ramosetron for the treatment of irritable bowel syndrome with diarrhea: a systematic review and meta-analysis of randomized controlled trials

Background

Ramosetron is a potent and selective serotonin type 3 receptor antagonist. This meta-analysis aimed to analyze the efficacy and safety of ramosetron for irritable bowel syndrome with diarrhea (IBS-D).

Methods

Pubmed, MEDLINE, EMBASE and the Cochrane Library were searched for randomized controlled trials investigating the efficacy and safety of ramosetron for IBS-D. Risk of bias was assessed as described in the Cochrane handbook. A random effects model was used to calculate the effects of ramosetron vs placebo on symptomatic improvements, including relief of overall IBS symptoms, relief of abdominal discomfort/pain, improvement in abnormal bowel habits, and improvement in stool consistency, expressed as pooled relative risks (RRs) with 95% confidence interval (CI). Adverse events data were also summarized with RRs.

Results

Four randomized controlled trials involving 1623 participants were included. Compared with placebo, ramosetron could lead to relief of overall IBS symptoms (RR 1.70; 95%CI 1.48, 1.95), relief of abdominal discomfort/pain (RR 1.41; 95%CI, 1.24, 1.59), improvement in abnormal bowel habits (RR 1.72; 95%CI, 1.50, 1.98) and improvement in stool consistency (RR 1.71; 95%CI 1.40, 2.08). Ramosetron could lead to relief of overall IBS symptoms in both male and female patients (RR; 95%CI: 1.94; 1.58, 2.38 and 1.49; 1.25, 1.79). The RR (95%CI) for reported adverse events of ramosetron vs placebo was 1.10 (0.97, 1.26) across all studies. No serious adverse events (e.g., ischemic colitis) were reported. The incidences of hard stool and constipation were higher in ramosetron group compared with placebo group (RR; 95%CI: 4.74; 3.00, 7.51 and 2.53; 1.57, 4.10, respectively).

Conclusions

Ramosetron had beneficial effects to both male and female IBS-D patients. Treatment with ramosetron could cause more hard stool and constipation, without severe adverse events.

Migraine in young females with irritable bowel syndrome: still a challenge

Migraine without aura is frequently reported in female patients with irritable bowel syndrome (IBS), but knowledge about the relationship between these two conditions is still lacking. This study was aimed to explore the particularities of migraine without aura in young female patients with IBS in order to establish a possible link between them. From a cohort of young female patients hospitalized with IBS in the Internal Medicine Department, 30 joined this pilot study, and they were assigned into two groups on the basis of presence or absence of migraine. In this sample, 15 patients have mild to moderate migraine without aura, with a recently taken normal brain scan, and 15 were without migraine. Diseases and conditions not related to migraine and other possible specific female comorbidities were ruled out. Patients undertook a thorough clinical examination in order to assess fibromyalgia (FM) and chronic pelvic pain (CPP), Questionnaires for migraine disability assessment (MIDAS) and generalized anxiety disorder (GAD) were performed. Laboratory testing of blood, urine, and stool were also performed. Optimized lymphocyte proliferation test for food allergy (FA) and a fecal microbiota (microbiological semiquantitative method) for dysbiosis (DB) assessment were performed. Based on the results, migraine-positive group displayed more severe comorbidities: FM (p=0.0002), FA (p=0.0006), CPP (p=0.026), higher scores of anxiety (GAD, p=0.0008), and more severe DB (p=0.0009). We noticed a strong positive correlation between MIDAS and GAD (r=0.83), a good positive correlation between MIDAS and DB (r=0.56), and a moderate positive correlation between MIDAS, FM, and FA (r=0.46 and 0.41). In conclusion, young female patients with IBS and migraine without aura displayed more severe associated issues - anxiety, intestinal DB, FM, FA, and CPP. The severity of migraine correlated well with anxiety range and DB magnitude and moderately with FM and FA.

Irritable bowel syndrome: prevalence, risk factors in an adult Lebanese population

Background

Very few studies report on the prevalence of irritable bowel syndrome (IBS) and its correlates in the Middle East. This study investigated Irritable Bowel Syndrome (IBS) prevalence in a sample of Lebanese adult individuals and associated demographic and behavioral lifestyle factors.

Methods

This is an observational population-based study. The target population is working Lebanese adults, eighteen-to-sixty five years old. The sample was selected from a convenience population of bank employees in different geographical areas in Lebanon. The study participants completed an anonymous self-administered questionnaire, to collect data on their socio-demographic, behavioral and life style characteristics, and diagnostic questions following Rome III criteria to assess IBS occurrence. The difference in IBS prevalence by socio-demographic characteristics, smoking, alcohol consumption, and physical activity was assessed by using the Chi-square test. Logistic regression adjusted odds ratios were used to investigate the association between risk factors and IBS.

Results

Data was collected from 553 individuals and consisted of 52.8% females (mean age 35.9 years, SD = 11.9) and 47.2% males (mean age = 36.1 years, SD = 10.3). The prevalence of IBS in the study population according to Rome III criteria was 20.1%. The bivariate analysis indicated that being younger than 30 years old, a female, an ever water pipe smoker, an ever alcohol consumer are significantly associated with a higher prevalence of IBS. Educational level, cigarettes smoking and physical exercise were not significantly associated with IBS occurrence. The logistic regression adjusted odds ratio showed that females were 1.67 times more likely to have IBS than males (P˂ 0.05). The participants aged less than 30 years old were at a higher risk of having IBS (P˂ 0.01). Those who ever smoked waterpipe were 1.63 times more likely to have IBS than those who never smoked waterpipe (P˂ 0.05). Those who were ever alcohol drinkers were twice as likely to have IBS than never-drinkers (P˂ 0.01).

Conclusion

New data on the high prevalence of IBS in an adult population in Lebanon has been reported. This is also the first study to investigate and show an association of waterpipe smoking and IBS. Further longitudinal studies are warranted to determine whether this association is causal.

Electronic supplementary material

The online version of this article (10.1186/s12876-017-0698-2) contains supplementary material, which is available to authorized users.

Sex differences in stress regulation of arousal and cognition

There are sex differences in the prevalence and presentation of many psychiatric disorders. For example, posttraumatic stress disorder (PTSD) and major depression are more common in women than men, and women with these disorders present with more hyperarousal symptoms than men. In contrast, attention deficit hyperactivity disorder (ADHD) and schizophrenia are more common in men than women, and men with these disorders have increased cognitive deficits compared to women. A shared feature of the aforementioned psychiatric disorders is the contribution of stressful events to their onset and/or severity. Here we propose that sex differences in stress responses bias females towards hyperarousal and males towards cognitive deficits. Evidence from clinical and preclinical studies is detailed. We also describe underlying neurobiological mechanisms. For example, sex differences in stress receptor signaling and trafficking in the locus coeruleus-arousal center are detailed. In learning circuits, evidence for sex differences in dendritic morphology is provided. Finally, we describe how evaluating sex-specific mechanisms for responding to stress in female and male rodents can lead to better treatments for stress-related psychiatric disorders.

Western Dietary Pattern Is Associated with Irritable Bowel Syndrome in the French NutriNet Cohort

Background: Diet appears to play a key role in the pathogenesis of the irritable bowel syndrome (IBS). Some dietary patterns (DP) could increase the risk of triggering or worsening IBS symptoms. This cross-sectional study aimed to assess the association between a posteriori derived DP and IBS in a large French population, the web-based NutriNet-Santé cohort. Methods: Study population included participants of the NutriNet-Santé study who completed a questionnaire based on Rome III criteria assessing IBS. A principal component analysis (PCA) was performed to identify major DPs based on 29 food groups' consumption. Associations between DP quintiles and IBS were investigated with multivariable logistic regressions. Results: 44,350 participants were included, with 2423 (5.5%) presenting IBS. Three major DP were extracted using PCA, "healthy," "western," and "traditional." After adjustments on confounders, the "western" DP was positively associated with IBS (OR _{Q5 vs. Q1} = 1.38, 95% CI 1.19-1.61, p trend < 0.0001) and the "traditional" DP was positively associated with IBS in women (OR _{Q5 vs. Q1} = 1.29 95% CI 1.08-1.54, p trend = 0.001). Conclusions: In this study, a "western" DP-highly correlated with the consumption of fatty and sugary products and snacks-was associated with a moderate increased risk of IBS.

Sex-Related Differences in Clinical Symptoms, Quality of Life, and Biochemical Factors in Irritable Bowel Syndrome

BACKGROUND

Due to the sex differences in physiological and psychological factors, it can be speculated that clinical presentation of symptoms in male and female patients with irritable bowel syndrome (IBS) might be different.

AIM

To evaluate sex-related differences in clinical symptoms, quality of life, and biochemical factors in IBS.

METHODS

Ninety IBS patients (29 men, 61 women (45 premenopausal, 16 postmenopausal)) were recruited from the outpatient clinic of the University Hospital. All the patients met the Rome III Diagnostic Criteria. The IBS severity score system (IBS-SSS), gastrointestinal (GI) symptoms, IBS specific quality of life (IBS-QoL), and biochemical factors (IL-17, IL-10, TNFα, malondialdehyde (MDA), total antioxidant capacity (TAC)) were assessed.

RESULTS

Diarrhea predominant IBS (IBS-D) was more common in men (44.8%), whereas constipation-predominant IBS (IBS-C) and alternating bowel habits IBS (IBS-A) were more common in women (39.3, 42.6%, respectively). The women had a greater severity of abdominal distention, rumbling, flatulence, and dissatisfaction with bowel habits as compared with men. The scores of IBS-QoL in women were significantly (P < 0.05) lower than those in men. Moreover, pro-inflammatory cytokines (IL-17, TNFα) increased, and anti-inflammatory cytokine (IL-10) decreased in women versus men. In addition, there was no significant difference (P > 0.05) between pre- and postmenopausal women in the severity of symptoms. All of the GI symptoms and IBS-SSS have a significant negative correlation with IBS-QoL in both men and women.

CONCLUSIONS

Female with IBS reports a greater severity of IBS symptoms, increased inflammatory cytokines, and has an impaired quality of life compared with male.

Irritable bowel syndrome is concentrated in people with higher educations in Iran: an inequality analysis

OBJECTIVES

Like any other health-related disorder, irritable bowel syndrome (IBS) has a differential distribution with respect to socioeconomic factors. This study aimed to estimate and decompose educational inequalities in the prevalence of IBS.

METHODS

Sampling was performed using a multi-stage random cluster sampling approach. The data of 1,850 residents of Kish Island aged 15 years or older were included, and the determinants of IBS were identified using a generalized estimating equation regression model. The concentration index of educational inequality in cases of IBS was estimated and decomposed as the specific inequality index.

RESULTS

The prevalence of IBS in this study was 21.57% (95% confidence interval [CI], 19.69 to 23.44%). The concentration index of IBS was 0.20 (95% CI, 0.14 to 0.26). A multivariable regression model revealed that age, sex, level of education, marital status, anxiety, and poor general health were significant determinants of IBS. In the decomposition analysis, level of education (89.91%), age (−11.99%), and marital status (9.11%) were the three main contributors to IBS inequality. Anxiety and poor general health were the next two contributors to IBS inequality, and were responsible for more than 12% of the total observed inequality.

CONCLUSIONS

The main contributors of IBS inequality were education level, age, and marital status. Given the high percentage of anxious individuals among highly educated, young, single, and divorced people, we can conclude that all contributors to IBS inequality may be partially influenced by psychological factors. Therefore, programs that promote the development of mental health to alleviate the abovementioned inequality in this population are highly warranted.

Childhood Irritable Bowel Syndrome Characteristics Are Related to Both Sex and Pubertal Development

OBJECTIVE

To determine the relationship of both pubertal development and sex to childhood irritable bowel syndrome (IBS) clinical characteristics including gastrointestinal symptoms (eg, abdominal pain) and psychological factors.

STUDY DESIGN

Cross-sectional study with children ages 7-17 years (n = 143) with a pediatric Rome III IBS diagnosis recruited from both primary and tertiary clinics between January 2009 and January 2014. Subjects completed 14-day prospective pain and stool diaries, as well as validated questionnaires assessing several psychological factors (somatization, depression, anxiety) and Tanner stage. Stool form ratings were completed using the Bristol Stool Form Scale.

RESULTS

Girls with higher Tanner scores (more mature pubertal development) had both decreased pain severity and pain interference; in contrast, boys with higher Tanner scores had both increasing pain severity (β = 0.40, P = .02) and pain interference (β = 0.16, P = .02). Girls (vs boys), irrespective of pubertal status, had both increased somatic complaints (P = .005) and a higher percentage (P = .01) of hard (Bristol Stool Form Scale type 1 or 2) stools. Pubertal status and sex did not significantly relate to IBS subtype, pain frequency, stooling frequency, anxiety, or depression.

CONCLUSIONS

In children with IBS, both pubertal development and/or sex are associated with abdominal pain severity, stool form, and somatization. These differences provide insight into the role of pubertal maturation during the transition from childhood to adult IBS.

In vitro spontaneous contractile activity of colonic smooth muscle in naive Lewis rats: Acute effect of gonadal hormones

OBJECTIVE

Functional gastrointestinal disorders affect females more often. Changes in colonic motility may be etiological co-factors for the clinical symptoms. The aim of the present study was to analyze the influence of gonadal hormones on colonic contractile activity.

METHODS

In vitro measurements of colonic contractile activity in longitudinal smooth muscle strips of female and male Lewis rats were performed in an organ chamber experiment. After the administration of a gonadal hormone estradiol [EST], progesterone [PROG] and testosterone [TEST]) or ethanol solution as control, stimulation with acetylcholine (ACh) or inhibition with norepinephrine (NE) was performed.

RESULTS

Compared to the smooth muscle strips of male rats, significantly higher spontaneous colonic contractile activity (SCCA) was observed in female animals. Increasing doses of ACh showed the progressive stimulation of SCCA whereas rising doses of NE resulted in a stepwise inhibition of SCCA, respectively. EST superfusion displayed an inhibitory effect on SCCA in both sexes and inhibited the ACh effect in female rats. Similarly, acute superfusion with high-dose PROG inhibited SCCA in females. Acute TEST superfusion inhibited SCCA in males and led to significant higher colonic contractile activity in males following subsequent stimulation with ACh. In female rats, the inhibitory effect of NE was reduced by prior exposure to TEST.

CONCLUSION

In our in vitro study the acute exposure of colonic smooth muscle tissue to gonadal hormones led to sex-dependent changes in SCCA and translated in a modified response of smooth muscle strips to both pro-contractile and anti-contractile neurotransmitters.

Consistent sex-dependent effects of PKMζ gene ablation and pharmacological inhibition on the maintenance of referred pain

BACKGROUND

Persistently active PKMζ has been implicated in maintaining spinal nociceptive sensitization that underlies pain hypersensitivity. However, evidence for PKMζ in the maintenance of pain hypersensitivity comes exclusively from short-term studies in males using pharmacological agents of questionable selectivity. The present study examines the contribution of PKMζ to long-lasting allodynia associated with neuropathic, inflammatory, or referred visceral and muscle pain in males and females using pharmacological inhibition or genetic ablation.

RESULTS

Pharmacological inhibition or genetic ablation of PKMζ reduced mild formalin pain and slowly developing contralateral allodynia in nerve-injured rats, but not moderate formalin pain or ipsilateral allodynia in models of neuropathic and inflammatory pain. Pharmacological inhibition or genetic ablation of PKMζ also effectively reduced referred visceral and muscle pain in male, but not in female mice and rats.

CONCLUSION

We show pharmacological inhibition and genetic ablation of PKMζ consistently attenuate long-lasting pain hypersensitivity. However, differential effects in models of referred versus inflammatory and neuropathic pain, and in males versus females, highlight the roles of afferent input-dependent masking and sex differences in the maintenance of pain hypersensitivity.

Effect of estrogen on visceral sensory function in a non-inflammatory colonic hypersensitivity rat model

BACKGROUND

Increased prevalence of functional gastrointestinal disorders in women and perimenstrually accentuated symptoms imply that sexual hormones play a crucial role in the pathogenesis of such syndromes. The aim of this study was to analyze the selective effect of estrogen on visceral sensitivity in gonadectomized female and male Lewis rats with or without prior treatment with butyrate enemas.

METHODS

Following ovariectomy (OVX) or orchiectomy (ORX) estradiol pellets (E2-P) or sham pellets (Sham-P) were implanted. After treatment with butyrate (BUT) or saline (NaCl) enemas, colorectal distensions (CRD) were performed and the visceromotor reflex (VMR) to CRD was measured by electromyography.

KEY RESULTS

Gender did not influence VMR to CRD in gonadectomized animals. VMR in E2-P animals compared to Sham-P animals was increased (635 ± 32 μVs vs 470 ± 39 μVs; p = 0.002). Overall, instillation of butyrate enemas did not influence VMR to CRD. A comparison of CRD clusters showed that butyrate enemas in the E2-P animals resulted in a significant sensitization in both OVX and ORX animals. In female rats, sensitization was also caused by estrogen substitution alone.

CONCLUSION & INFERENCES

In our animal model, estrogen is a strong factor for an increase in visceral sensory function. Surprisingly, the treatment with butyrate alone did not evoke a general rise in VMR to CRD. Rats treated with butyrate enemas and under selective estrogen substitution developed visceral sensitization during the series of CRDs.

Comparison of Rectal and Esophageal Sensitivity in Women With Functional Heartburn

This study tested the primary hypothesis that there is a correlation of maximum pain threshold (MPT) in the esophagus and rectum in persons with functional heartburn. Secondary aims evaluated correlations with initial perception threshold (IPT) and pain threshold (PT). This study explored objective sensory endpoints of IPT, PT, and MPT in the esophagus and rectum of 14 females with functional heartburn to determine whether visceral hypersensitivity is generalized or organ-specific. Data on volume and pressure measurements at IPT, PT, and MPT with esophageal and rectal barostat distention were collected. The relationship of sensation and pain to volume, pressure, and compliance was analyzed. Esophageal and rectal IPT balloon volume scores were highly and significantly correlated (r = .61, p = .02). Esophageal and rectal PT balloon volume scores were highly and significantly correlated (r = .6, p = .02). Esophageal and rectal MPT balloon volume scores were not correlated (r = .35, p = .26). The correlation of visceral sensitivity in the esophagus and rectum in persons with functional heartburn supports the hypothesis that visceral sensory changes in functional gastrointestinal disorders are not organ specific.

Gastrointestinal Symptoms in Celiac Disease Patients on a Long-Term Gluten-Free Diet

Experience suggests that many celiac patients suffer from persistent symptoms despite a long-term gluten-free diet (GFD). We investigated the prevalence and severity of these symptoms in patients with variable duration of GFD. Altogether, 856 patients were classified into untreated (n = 128), short-term GFD (1–2 years, n = 93) and long-term GFD (≥3 years, n = 635) groups. Analyses were made of clinical and histological data and dietary adherence. Symptoms were evaluated by the validated GSRS questionnaire. One-hundred-sixty healthy subjects comprised the control group. Further, the severity of symptoms was compared with that in peptic ulcer, reflux disease, inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Altogether, 93% of the short-term and 94% of the long-term treated patients had a strict GFD and recovered mucosa. Untreated patients had more diarrhea, indigestion and abdominal pain than those on GFD and controls. There were no differences in symptoms between the short- and long-term GFD groups, but both yielded poorer GSRS total score than controls (p = 0.03 and p = 0.05, respectively). Furthermore, patients treated 1–2 years had more diarrhea (p = 0.03) and those treated >10 years more reflux (p = 0.04) than controls. Long-term treated celiac patients showed relatively mild symptoms compared with other gastrointestinal diseases. Based on our results, good response to GFD sustained in long-term follow-up, but not all patients reach the level of healthy individuals.

The effect of sex and irritable bowel syndrome on HPA axis response and peripheral glucocorticoid receptor expression

BACKGROUND AND AIMS

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been reported in irritable bowel syndrome (IBS). Enhanced HPA axis response has been associated with reduced glucocorticoid receptor (GR) mediated negative feedback inhibition. We aimed to study the effects of IBS status, sex, or presence of early adverse life events (EAL) on the cortisol response to corticotropin-releasing factor (CRF) and adrenocorticotropic hormone (ACTH), and on GR mRNA expression in peripheral blood mononuclear cells (PBMCs).

METHODS

Rome III+ IBS patients and healthy controls underwent CRF (1μg/kg ovine) and ACTH (250μg) stimulation tests with serial plasma ACTH and cortisol levels measured (n=116). GR mRNA levels were measured using quantitative PCR (n=143). Area under the curve (AUC) and linear mixed effects models were used to compare ACTH and cortisol response measured across time between groups.

RESULTS

There were divergent effects of IBS on the cortisol response to ACTH by sex. In men, IBS was associated with an increased AUC (p=0.009), but in women AUC was blunted in IBS (p=0.006). Men also had reduced GR mRNA expression (p=0.007). Cumulative exposure to EALs was associated with an increased HPA response. Lower GR mRNA was associated with increased pituitary HPA response and increased severity of overall symptoms and abdominal pain in IBS.

CONCLUSION

This study highlights the importance of considering sex in studies of IBS and the stress response in general. Our findings also provide support for PBMC GR mRNA expression as a peripheral marker of central HPA response.

Sex Differences in Cannabis Use and Effects: A Cross-Sectional Survey of Cannabis Users

Introduction: Despite known sex differences in the endocannabinoid system of animals, little attention has been paid to sex differences in human's cannabis use patterns and effects. The purpose of the present study was to examine sex differences in cannabis use patterns and effects in a large sample of recreational and medical cannabis users.

Methods: A large sample (n=2374) of cannabis users completed an anonymous, online survey that assessed their cannabis use practices and experiences, including the short-term acute effects of cannabis and withdrawal effects. A subsample of 1418 medical cannabis users further indicated the medical conditions for which they use cannabis and its perceived efficacy.

Results: The results indicated that men reported using cannabis more frequently and in higher quantities than did women. Men were more likely to report using joints/blunts, vaporizers, and concentrates, while women were more likely to report using pipes and oral administration. Men were more likely than women to report increased appetite, improved memory, enthusiasm, altered time perception, and increased musicality when high, while women were more likely than men to report loss of appetite and desire to clean when high. Men were more likely than women to report insomnia and vivid dreams during periods of withdrawal, while women were more likely than men to report nausea and anxiety as withdrawal symptoms. Sex differences in the conditions for which medical cannabis is used, and its efficacy, were trivial.

Conclusions: These results may be used to focus research on biological and psychosocial mechanisms underlying cannabis-related sex differences, to inform clinicians treating individuals with cannabis use disorders, and to inform cannabis consumers, clinicians, and policymakers about the risks and benefits of cannabis for both sexes.

Sex difference in pathology of the ageing gut mediates the greater response of female lifespan to dietary restriction

Women live on average longer than men but have greater levels of late-life morbidity. We have uncovered a substantial sex difference in the pathology of the aging gut in Drosophila. The intestinal epithelium of the aging female undergoes major deterioration, driven by intestinal stem cell (ISC) division, while lower ISC activity in males associates with delay or absence of pathology, and better barrier function, even at old ages. Males succumb to intestinal challenges to which females are resistant, associated with fewer proliferating ISCs, suggesting a trade-off between highly active repair mechanisms and late-life pathology in females. Dietary restriction reduces gut pathology in aging females, and extends female lifespan more than male. By genetic sex reversal of a specific gut region, we induced female-like aging pathologies in males, associated with decreased lifespan, but also with a greater increase in longevity in response to dietary restriction.

Fatigue in Irritable Bowel Syndrome: A Systematic Review and Meta-analysis of Pooled Frequency and Severity of Fatigue

PURPOSE

Fatigue is the third most common "extraintestinal" complaint of patients with irritable bowel syndrome (IBS), but it is still poorly understood. This study aimed to review characteristics of IBS-associated fatigue and to examine pooled frequency, severity of fatigue, and correlations of related factors with fatigue in IBS via meta-analyses.

METHODS

Publications were searched in eight databases from 1995 to 2014. Random effects meta-analyses were applied with standard error, weighted effect size, and correlation-based measure of effect size.

RESULTS

Twenty-four studies were included in systematic review. Seventeen studies were used for meta-analyses (2 studies were excluded in the frequency of fatigue analysis due to data unavailability). Using "tiredness" to define fatigue, and Fatigue Impact Scale to assess fatigue were the most frequently used across the studies. Gastrointestinal symptoms, psychological distress, and health-related quality of life were the most common correlates with fatigue. The pooled frequency of fatigue was 54.2% [95% confidence interval (38.5, 69.4)]. Metaregression on the frequency of fatigue showed positive and significant relations with tertiary care settings, female sex, and younger age. There was a negatively moderate relationship between the severity of fatigue and health-related quality of life score (correlation-based measure of effect size: -.378).

CONCLUSIONS

Fatigue is prevalent among patients with IBS and commonly co-occurs with other symptoms. This is the first study to fully examine fatigue in IBS, which shed light on the comprehensive management of fatigue in this patient group. Future research is warranted to further explore fatigue-related factors and underlying mechanisms of fatigue in IBS.

Abnormal Amygdala Resting-State Functional Connectivity in Irritable Bowel Syndrome

BACKGROUND AND PURPOSE

Functional neuroimaging studies in irritable bowel syndrome have revealed abnormalities in the corticolimbic regions, specifically, hyperactivity of the amygdala during visceral and somatic stimulation. This study investigated changes in the neural circuitry of the amygdala in patients with irritable bowel syndrome based on resting-state functional connectivity.

MATERIALS AND METHODS

Functional MR imaging data were acquired from 31 patients with irritable bowel syndrome and 32 healthy controls (matched for age, sex, and educational level) during rest, and the resting-state functional connectivity of bilateral amygdalae was compared. Multiple regression was performed to investigate the relationship between clinical indices of patients with irritable bowel syndrome and resting-state functional connectivity.

RESULTS

Compared with healthy controls, patients with irritable bowel syndrome had higher positive resting-state functional connectivity between the amygdala and insula, midbrain, parahippocampal gyrus, pre- and postcentral gyri, and supplementary motor area. The inclusion of anxiety and depression as covariates did not alter amygdala resting-state functional connectivity differences between the study groups. Multiple covariate regression results showed that the pain intensity in patients with irritable bowel syndrome positively correlated with resting-state functional connectivity between the amygdala and supplementary motor area, pre- and postcentral gyri, and insula, while the Irritable Bowel Syndrome-Symptom Severity Score positively correlated with resting-state functional connectivity between the amygdala and insula and midbrain.

CONCLUSIONS

Patients with irritable bowel syndrome showed disturbed amygdala resting-state functional connectivity with the corticolimbic regions, which could partly account for the enhanced emotional arousal and visceral information processing associated with irritable bowel syndrome.

Efficacy of Lactobacillus casei Shirota for patients with irritable bowel syndrome

BACKGROUND AND AIMS

Meta-analyses point to a modest but significant effect of probiotics on symptoms in irritable bowel syndrome (IBS). We aimed to assess the effect of the probiotic Lactobacillus casei Shirota (LcS) on symptoms and quality of life in IBS patients in a randomized, double-blind, placebo-controlled intervention study.

MATERIALS AND METHODS

IBS patients (Rome II) between 18 and 65 years of age were included. The study consisted of an 8-week intervention period in which the participants received probiotic (LcS) or placebo twice daily, followed by an 8-week follow-up period. Symptom diaries and quality of life were scored at weeks 0, 8 and 16. The primary outcome parameter was a decrease of at least 30% in a composite mean symptom score (MSS) at week 8 on the basis of an intention-to-treat analysis.

RESULTS

Thirty-nine individuals (67% women) were included in the probiotic group and 41 individuals (71% women) were included in the placebo group. After the intervention period, the mean relative improvement did not reach 30% for MSS or any individual symptom score. After follow-up (week 16), a mean improvement of at least 30% was achieved for MSS in the probiotic group, but no significant difference was found between both treatment groups (mean±SD: 34±7%; 13±8%, P=0.06).

CONCLUSION

After probiotic treatment with LcS, no improvement of 30% in MSS was observed after 8 weeks.

Functional Gastrointestinal Symptoms Are Associated with Higher Serum Total IgE Levels, but Less Atopic Sensitization

BACKGROUND

The relation of gastrointestinal (GI) complaints to IgE-mediated allergy is not well understood. Increased numbers of "IgE-armed" mast cells have been observed in duodenal mucosa of patients with functional GI complaints.

AIMS

To explore whether total IgE and atopic sensitization were associated with functional GI complaints.

METHODS

Levels of serum total and specific IgE and GI complaints were measured in 161 patients and in a general population sample of 478 persons. Standard inhalant allergens were measured in the patient group, and selected inhalant allergens in the general population. GI complaints were assessed by two standardized questionnaires. The associations between GI complaints and total IgE were analyzed in multiple regression models.

RESULTS

GI complaints were positively associated with higher total IgE levels (all: b = 0.028, p = 0.012; patient group: b = 0.038, p = 0.072; general population: b = 0.038, p = 0.005), but negatively associated with atopic sensitization (all: b = -11.256, p = 0.181; patient group: b = -85.667, p < 0.001; general population: b = -14.394, p = 0.083). The relationship between total IgE and GI complaints was consistent among sensitized and non-sensitized persons, among men and women, and across age groups.

CONCLUSION

Serum total IgE was positively associated with GI complaints, while atopic sensitization was inversely associated with GI complaints. This suggests that IgE-mediated immunology plays a role in the pathophysiology of functional GI complaints. The biological mechanisms reflected in higher total IgE levels, but less atopic sensitization, warrant further studies.

Unique Microstructural Changes in the Brain Associated with Urological Chronic Pelvic Pain Syndrome (UCPPS) Revealed by Diffusion Tensor MRI, Super-Resolution Track Density Imaging, and Statistical Parameter Mapping: A MAPP Network Neuroimaging Study

Studies have suggested chronic pain syndromes are associated with neural reorganization in specific regions associated with perception, processing, and integration of pain. Urological chronic pelvic pain syndrome (UCPPS) represents a collection of pain syndromes characterized by pelvic pain, namely Chronic Prostatitis/Chronic Pelvic Pain Syndrome (CP/CPPS) and Interstitial Cystitis/Painful Bladder Syndrome (IC/PBS), that are both poorly understood in their pathophysiology, and treated ineffectively. We hypothesized patients with UCPPS may have microstructural differences in the brain compared with healthy control subjects (HCs), as well as patients with irritable bowel syndrome (IBS), a common gastrointestinal pain disorder. In the current study we performed population-based voxel-wise DTI and super-resolution track density imaging (TDI) in a large, two-center sample of phenotyped patients from the multicenter cohort with UCPPS (N = 45), IBS (N = 39), and HCs (N = 56) as part of the MAPP Research Network. Compared with HCs, UCPPS patients had lower fractional anisotropy (FA), lower generalized anisotropy (GA), lower track density, and higher mean diffusivity (MD) in brain regions commonly associated with perception and integration of pain information. Results also showed significant differences in specific anatomical regions in UCPPS patients when compared with IBS patients, consistent with microstructural alterations specific to UCPPS. While IBS patients showed clear sex related differences in FA, MD, GA, and track density consistent with previous reports, few such differences were observed in UCPPS patients. Heat maps illustrating the correlation between specific regions of interest and various pain and urinary symptom scores showed clustering of significant associations along the cortico-basal ganglia-thalamic-cortical loop associated with pain integration, modulation, and perception. Together, results suggest patients with UCPPS have extensive microstructural differences within the brain, many specific to syndrome UCPPS versus IBS, that appear to be localized to regions associated with perception and integration of sensory information and pain modulation, and seem to be a consequence of longstanding pain.

Gender differences in irritable bowel syndrome: the interpersonal connection

BACKGROUND

While irritable bowel syndrome (IBS) affects women more than men, the reasons are unclear. Research on the female preponderance of IBS has focused on gender differences in sex-linked biological processes; much less attention has been paid to the role of psychosocial factors. Interpersonal difficulties may be one source of stress that may significantly impact on women with IBS. Because of the importance that women attach to relationships, we suspected they would be more reactive to interpersonal stress.

METHODS

A total of 283 (M age = 41 years, F = 80%), Rome III-diagnosed IBS patients completed a test battery that included the IBS Symptom Severity Scale, McGill Pain Questionnaire, Inventory of Interpersonal Problems (IIP), interpersonal support evaluation list (social support), Negative Interactions Scale, Brief Symptom Inventory (distress), Beck Depression Inventory, Anxiety Sensitivity Inventory, and IBS-Quality of Life as part of baseline assessment of an NIH trial.

KEY RESULTS

Males scored higher on two IIP scales reflecting a hostile-dominant interpersonal pattern, and reported less social support. The quality of relationship problems (more interpersonal difficulties, lower support) correlated with IBS symptom severity as measured mainly by gastroenterologists.

CONCLUSIONS & INFERENCES

Male, not female, IBS patients reported more interpersonal difficulties. Male patients-a population for whom little is known-are characterized by hostile-dominant interpersonal problems. This finding has clinical importance, given that relationship problems may influence MDs' estimation of IBS symptom severity and undermine the physician-patient relationship.

How many segments are necessary to characterize delayed colonic transit time?

BACKGROUND AND AIMS

Measuring colonic transit time with radiopaque markers is simple, inexpensive, and very useful in constipated patients. Yet, the algorithm used to identify colonic segments is subjective, rather than founded on prior experimentation. The aim of the present study is to describe a rational way to determine the colonic partition in the measurement of colonic transit time.

METHODS

Colonic transit time was measured in seven segments: ascending colon, hepatic flexure, right and left transverse colon, splenic flexure, descending colon, and rectosigmoid in 852 patients with functional bowel and anorectal disorders. An unsupervised algorithm for modeling Gaussian mixtures served to estimate the number of subgroups from this oversegmented colonic transit time. After that, we performed a k-means clustering that separated the observations into homogenous groups of patients according to their oversegmented colonic transit time.

RESULTS

The Gaussian mixture followed by the k-means clustering defined 4 populations of patients: "normal and fast transit" (n = 548) and three groups of patients with delayed colonic transit time "right delay" (n = 82) in which transit is delayed in the right part of the colon, "left delay" (n = 87) with transit delayed in the left part of colon and "outlet constipation" (n = 135) for patients with transit delayed in the terminal intestine. Only 3.7 % of patients were "erroneously" classified in the 4 groups recognized by clustering.

CONCLUSIONS

This unsupervised analysis of segmental colonic transit time shows that the classical division of the colon and the rectum into three segments is sufficient to characterize delayed segmental colonic transit time.

Estradiol modulates visceral hyperalgesia by increasing thoracolumbar spinal GluN2B subunit activity in female rats

BACKGROUND

We previously reported estrogen modulates spinal N-methyl-d-aspartate (NMDA) receptor processing of colorectal pain through changes in spinal GluN1 subunit phosphorylation/expression. The purpose of this study was to investigate whether spinal GluN2B containing NMDA receptors are involved in estrogen modulation of visceral pain processing.

METHODS

Behavioral, molecular, and immunocytochemical techniques were used to determine spinal GluN2B expression/phosphorylation and function 48 h following subcutaneous injection of estradiol (E2) or vehicle (safflower oil, Saff oil) in ovariectomized rats in the absence or presence of colonic inflammation induced by mustard oil.

KEY RESULTS

E2 increased the magnitude of the visceromotor response (VMR) to colorectal distention compared to Saff oil in non-inflamed rats. Intrathecal injection of the GluN2B subunit antagonist, Ro 25-6981, had no effect on the VMR in non-inflamed E2 or Saff oil rats. Colonic inflammation induced visceral hyperalgesia in E2, but not Saff oil rats. Visceral hyperalgesia in E2 rats was blocked by intrathecal GluN2B subunit selective antagonists. In inflamed rats, E2 increased GluN2B protein and gene expression in the thoracolumbar (TL), but not lumbosacral (LS), dorsal spinal cord. Immunocytochemical labeling showed a significant increase in GluN2B subunit in the superficial dorsal horn of E2 rats compared to Saff oil rats.

CONCLUSIONS & INFERENCES

These data support the hypothesis that estrogen increases spinal processing of colonic inflammation-induced visceral hyperalgesia by increasing NMDA receptor activity. Specifically, an increase in the activity of GluN2B containing NMDA receptors in the TL spinal cord by estrogen underlies visceral hypersensitivity in the presence of colonic inflammation.

Clinical, metabolic, and psychological characteristics in patients with gastroesophageal reflux disease overlap with irritable bowel syndrome

OBJECTIVES

Gastroesophageal reflux disease (GERD) and irritable bowel syndrome (IBS) are highly prevalent in the general population, with significant symptom overlap, whereas the interaction between both remains poorly understood. We aim to identify the clinical and psychological factors that contribute toward the overlap of GERD and IBS.

PATIENTS AND METHODS

We carried out a case-control study among 806 GERD and 176 IBS patients from a health check-up cohort (n=2604). All participants were evaluated using the Reflux Disease Questionnaire score, the Pittsburgh Sleep Quality Index score, the Taiwanese Depression Questionnaire score, and the State-Trait Anxiety Inventory score. Endoscopic findings were classified according to the Los Angeles classification. IBS was diagnosed on the basis of Rome III criteria, and metabolic syndrome was defined by the National Cholesterol Education Program Adult Treatment Panel III definition.

RESULTS

Among the study population, 727 individuals had GERD, 97 individuals had IBS, and 79 individuals had a diagnosis of both GERD and IBS (GERD-I). GERD-I patients had more severe GERD symptoms compared with patients with GERD or IBS alone (P<0.0001). Moreover, GERD-I patients had more frequent healthcare-seeking behavior, decreased quality of sleep, and higher depression scores than patients with GERD (P<0.0001) or IBS alone (P<0.05). In addition, GERD-I patients had lower blood pressure, waist-to-hip ratio, and higher serum high-density lipoprotein levels than those with GERD alone (P<0.05).

CONCLUSION

GERD patients overlapping with IBS have different clinical and psychological profiles than those with GERD or IBS alone. Our study suggests that awareness of these symptom presentations will help optimize the treatment of these conditions.

Prevalence and factors associated with irritable bowel syndrome among university students in Lebanon: Findings from a cross-sectional study

AIM: To describe the bowel habits and the prevalence of irritable bowel syndrome (IBS) and to investigate the influence of health behavior and social factors on IBS prevalence in university students.

METHODS: This cross-sectional study was conducted at five major universities in Greater Beirut and its suburbs, between February and June 2014. Using a convenience sample, a total of 813 students aged 18 years old and above participated in this study. Participants were asked to complete a comprehensive anonymous questionnaire which detailed characteristics on socio-demographic, health-related, and lifestyle factors, as well as IBS. The ROME III criteria were used as a tool to ascertain IBS. A χ² test was used to determine differences between categorical variables; stepwise logistic regression was used to measure the association between IBS and its risk factors.

RESULTS: An overall prevalence of IBS of 20% was recorded among university students. The bivariate analysis showed that females were significantly more likely to report having IBS than males (29.1% vs 18.2%, P < 0.01). Those living at the school dormitory or in a private residence (39.5%) were more likely to have IBS than those living with their families (16.3%) (P < 0.01). The multivariate analysis showed that those who had a relatively high family income level (US$ > 2000) were almost 6 times more likely to report having IBS than their counterparts.

CONCLUSION: This is the first study to describe the nature of IBS among young adults in Lebanon. The prevalence of IBS among university students in our sample was higher than that reported in the West.

Acute Uterine Irritation Provokes Colonic Motility via Transient Receptor Potential A1-dependent Spinal NR2B Phosphorylation in Rats

Background:

Patients with inflammatory gynecological/obstetrical problems often complain of irritable bowel syndrome. The authors examined whether acute uterus irritation reflexively provokes colonic motility in rat preparations.

Methods:

A modified colon manometry and striated abdominal muscle electromyogram activity in response to mustard oil (MO) instillation into the uterine horn were continuously recorded in anesthetized rats. The lumbosacral (L6-S1) dorsal horn was dissected to assess the level and the cellular location of phosphorylated NR2B subunit using Western blotting and immunofluorescence analysis, respectively. Finally, the uterine transient receptor potential A1 or spinal NR2B subunit was pharmacologically blocked to elucidate its roles.

Results:

MO (0.1%, 0.2 ml) injected into the lower uterine horn dramatically provoked colonic hypermotility characterized by rhythmic colonic contractions (about 3–4 contractions per 10 min, n = 7) accompanied by synchronized electromyogram firing in the abdominal muscle (about 4–5 folds of control, n = 7). In addition to provoking colonic hypermotility, MO administration also up-regulated phosphorylated (about 2–3 folds of control, n = 7), but not total, NR2B expression in the dorsal horn neurons. Both intrathecal Ro 25–6981 (a selective NR2B subunit antagonist; 10 μM, 10 μl) and intrauterine HC-030031 (a selective transient receptor potential A1 receptor antagonist; 30 mg/kg, 0.2 ml) injected before the MO instillation attenuated the MO-induced colonic hypermotility and spinal NR2B phosphorylation.

Conclusion:

The comorbidity of gynecological/obstetrical and gastrointestinal problems is not coincidental but rather causal in nature, and clinicians should investigate for gynecological/urological diseases in the setting of bowel problems with no known pathological etiology.

Fear of severe pain mediates sex differences in pain sensitivity responses to thermal stimuli

The purpose of this paper was to examine the relationship of sex and pain-related fear in pain intensity reports to thermal stimuli and whether sex differences in reported pain intensity were mediated by pain-related fear. 177 participants, 124 female (23.5 ± 4.5 years old), filled out a demographic and fear of pain questionnaire (FPQ-III). Experimental pain testing was performed using thermal stimuli applied to the lower extremity. Participants rated the intensity of pain using the numerical pain rating scale (NPRS). Independent t-tests, Sobel's test, and linear regression models were performed to examine the relationships between sex, fear of pain, and pain sensitivity. We found significant sex differences for thermal pain threshold temperatures (t = 2.04,  P = 0.04) and suprathreshold pain ratings for 49°C (t = -2.12,  P = 0.04) and 51°C (t = -2.36,  P = 0.02). FPQ-severe score mediated the effect of suprathreshold pain ratings of 49° (t = 2.00,  P = 0.05), 51° (t = 2.07,  P = 0.04), and pain threshold temperatures (t = -2.12,  P = 0.03). There are differences in the pain sensitivity between sexes, but this difference may be mediated by baseline psychosocial factors such as fear of pain.

Patients with chronic visceral pain show sex-related alterations in intrinsic oscillations of the resting brain

Abnormal responses of the brain to delivered and expected aversive gut stimuli have been implicated in the pathophysiology of irritable bowel syndrome (IBS), a visceral pain syndrome occurring more commonly in women. Task-free resting-state functional magnetic resonance imaging (fMRI) can provide information about the dynamics of brain activity that may be involved in altered processing and/or modulation of visceral afferent signals. Fractional amplitude of low-frequency fluctuation is a measure of the power spectrum intensity of spontaneous brain oscillations. This approach was used here to identify differences in the resting-state activity of the human brain in IBS subjects compared with healthy controls (HCs) and to identify the role of sex-related differences. We found that both the female HCs and female IBS subjects had a frequency power distribution skewed toward high frequency to a greater extent in the amygdala and hippocampus compared with male subjects. In addition, female IBS subjects had a frequency power distribution skewed toward high frequency in the insula and toward low frequency in the sensorimotor cortex to a greater extent than male IBS subjects. Correlations were observed between resting-state blood oxygen level-dependent signal dynamics and some clinical symptom measures (e.g., abdominal discomfort). These findings provide the first insight into sex-related differences in IBS subjects compared with HCs using resting-state fMRI.

Sex-related differences of cortical thickness in patients with chronic abdominal pain

Background & Aims

Regional reductions in gray matter (GM) have been reported in several chronic somatic and visceral pain conditions, including irritable bowel syndrome (IBS) and chronic pancreatitis. Reported GM reductions include insular and anterior cingulate cortices, even though subregions are generally not specified. The majority of published studies suffer from limited sample size, heterogeneity of populations, and lack of analyses for sex differences. We aimed to characterize regional changes in cortical thickness (CT) in a large number of well phenotyped IBS patients, taking into account the role of sex related differences.

Methods

Cortical GM thickness was determined in 266 subjects (90 IBS [70 predominantly premenopausal female] and 176 healthy controls (HC) [155 predominantly premenopausal female]) using the Laboratory of Neuro Imaging (LONI) Pipeline. A combined region of interest (ROI) and whole brain approach was used to detect any sub-regional and vertex-level differences after removing effects of age and total GM volume. Correlation analyses were performed on behavioral data.

Results

While IBS as a group did not show significant differences in CT compared to HCs, sex related differences were observed both within the IBS and the HC groups. When female IBS patients were compared to female HCs, whole brain analysis showed significant CT increase in somatosensory and primary motor cortex, as well as CT decrease in bilateral subgenual anterior cingulate cortex (sgACC). The ROI analysis showed significant regional CT decrease in bilateral subregions of insular cortex, while CT decrease in cingulate was limited to left sgACC, accounting for the effect of age and GM volume. Several measures of IBS symptom severity showed significant correlation with CT changes in female IBS patients.

Conclusions

Significant, sex related differences in CT are present in both HCs and in IBS patients. The biphasic neuroplastic changes in female IBS patients are related to symptom severity.

Effects of demographic factors, body mass index, alcohol drinking and smoking habits on irritable bowel syndrome: a case control study

BACKGROUND

Irritable Bowel Syndrome (IBS) is a common functional gastrointestinal disorder.

AIMS

To identify demographic factors in patients with IBS.

SUBJECTS AND METHODS

One-hundred and fifty three IBS patients seen at Taleghani Hospital Gastroenterology Clinic and met the Rome III criteria and 163 peoples who did not meet IBS criteria were consecutively enrolled. Both groups were asked to complete a self-rating questionnaire containing information, which included questions about age, sex, monthly income, education level, marital status, height, weight, alcohol drinking and smoking habits. Student's t-test, Pearson's Chi-square and logistic regression were used to statistical analysis.

RESULTS

The mean (SD) age for IBS patients 36.3 (13.5) years and 33.1 (9.9) years in non-IBS group (P < 0.001). Frequency of IBS defined by Rome III criteria was higher in females and younger individuals. Univariate analysis showed that IBS in males was associated with a lower monthly income and educational level and in females younger age, single, lower monthly income and educational level, body mass index (BMI), and unemployment status. Multivariate logistic regression identified a low level of education in males (Odds ratio [OR] = 3.6, 95% Confidence interval [CI]: 1.4-9.6) and in females, lower education level (OR = 2.4, 95% CI: 1.1-5.2), lower BMI (OR = 0.94, 95% CI: 0.89-0.99), unemployed (OR = 0.31, 95% CI: 0.11-0.85) and smoking (OR = 6.2, 95% CI: 1.03-37.2).

CONCLUSION

We identified demographic factors in IBS patients. Being single and having a lower educational level, income, lower BMI and being unemployed were the most important factors associated with IBS, particularly in females.

Sex differences in emotion-related cognitive processes in irritable bowel syndrome and healthy control subjects

Greater responsiveness of emotional arousal circuits in relation to delivered visceral pain has been implicated as underlying central pain amplification in irritable bowel syndrome (IBS), with female subjects showing greater responses than male subjects. Functional magnetic resonance imaging was used to measure neural responses to an emotion recognition paradigm, using faces expressing negative emotions (fear and anger). Sex and disease differences in the connectivity of affective and modulatory cortical circuits were studied in 47 IBS (27 premenopausal female subjects) and 67 healthy control subjects (HCs; 38 premenopausal female subjects). Male subjects (IBS+HC) showed greater overall brain responses to stimuli than female subjects in prefrontal cortex, insula, and amygdala. Effective connectivity analyses identified major sex- and disease-related differences in the functioning of brain networks related to prefrontal regions, cingulate, insula, and amygdala. Male subjects had stronger connectivity between anterior cingulate subregions, amygdala, and insula, whereas female subjects had stronger connectivity to and from the prefrontal modulatory regions (medial/dorsolateral cortex). Male IBS subjects demonstrate greater engagement of cortical and affect-related brain circuitry compared to male control subjects and female subjects, when viewing faces depicting emotions previously shown to elicit greater behavioral and brain responses in male subjects.

Association between symptoms of irritable bowel syndrome and methane and hydrogen on lactulose breath test

Whether hydrogen and methane gas produced during lactulose breath test (LBT) are associated with symptoms of irritable bowel syndrome (IBS) is not determined. We aimed to investigate whether hydrogen and methane on LBT are associated with IBS symptoms. Sixty-eight IBS patients meeting the Rome III criteria for IBS, and 55 healthy controls, underwent LBT. The IBS subjects recorded their customary gastrointestinal symptoms on a questionnaire using visual analogue scales. LBT positivity was defined to be above 20 ppm rise of hydrogen or 10 ppm rise of methane within 90 min. Gas amounts produced during LBT were determined by calculating area under the curve of hydrogen and methane excretion. Symptom severity scores were not different between the LBT (+) IBS and LBT (-) IBS subjects and also between methane producers and non-methane producers. Gas amounts produced during LBT were not associated with IBS symptoms, except a weak correlation between total gas amounts and a few IBS symptoms such as bloating (r = 0.324, P = 0.039), flatulence (r = 0.314, P = 0.046) and abdominal pain (r = 0.364, P = 0.018) only in LBT (+) IBS. In conclusion, hydrogen and methane gas on LBT are not useful for predicting the customary symptoms and subtypes of IBS.

Negative aspects of close relationships are more strongly associated than supportive personal relationships with illness burden of irritable bowel syndrome

OBJECTIVE

This study assessed the relative magnitude of associations between IBS outcomes and different aspects of social relationships (social support, negative interactions).

METHOD

Subjects included 235 Rome III diagnosed IBS patients (M age=41yrs, F=78%) without comorbid GI disease. Subjects completed a testing battery that included the Interpersonal Support Evaluation List (Social Support or SS), Negative Interaction (NI) Scale, IBS Symptom Severity Scale (IBS-SSS), IBS-QOL, BSI Depression, STAI Trait Anxiety, SOMS-7 (somatization), Perceived Stress Scale, and a medical comorbidity checklist.

RESULTS

After controlling for demographic variables, both SS and NI were significantly correlated with all of the clinical variables (SS r's=.20 to .36; NI r's=.17 to .53, respectively; ps<.05) save for IBS symptom severity (IBS-SSS). NI, but not SS, was positively correlated with IBS-SSS. After performing r-to-z transformations on the correlation coefficients and then comparing z-scores, the correlation between perceived stress, and NI was significantly stronger than with SS. There was no significant difference between the strength of correlations between NI and SS for depression, somatization, trait anxiety, and IBSQOL. A hierarchical linear regression identified both SS and NI as significant predictors of IBS-QOL.

CONCLUSIONS

Different aspects of social relationships - support and negative interactions - are associated with multiple aspects of IBS experience (e.g. stress, QOL impairment). Negative social relationships marked by conflict and adverse exchanges are more consistently and strongly related to IBS outcomes than social support.

An evaluation of the FDA responder endpoint for IBS-C clinical trials: analysis of data from linaclotide Phase 3 clinical trials

BACKGROUND

Our objective was to evaluate the performance of the Food and Drug Administration (FDA) Responder Endpoint for clinical trials in IBS-C, using data from two large Phase 3 clinical trials of linaclotide. The FDA interim endpoint requires that, for 50% of trial weeks, patients report ≥30% decrease in Abdominal Pain at its worst and (in the same week) an increase in Complete Spontaneous Bowel Movements (CSBMs) of ≥1 from baseline.

METHODS

Anchor-based methodology was used to estimate thresholds of clinically meaningful change using symptom-specific patient rating of change questions (PRCQs) and symptom severity questions. The diagnostic accuracy of the FDA Responder Endpoint was assessed using sensitivity/specificity-based methods.

KEY RESULTS

Using anchor-based methods, the estimates of the clinically meaningful improvement thresholds for Abdominal Pain ranged from 25.9% to 32.4% and thresholds for increase in weekly CSBM rate ranged from 1.4 to 1.6 CSBMs per week. Compared with the symptom-specific PRCQs for patient rating of relief, the FDA Responder Endpoint has a sensitivity of 60.7%, a specificity of 93.5%, and an accuracy of 82.0%. Changing the number of weeks required to be a responder or the percentage improvement in the Abdominal Pain criteria did not result in notable improvement in the accuracy of the FDA Responder Endpoint.

CONCLUSIONS & INFERENCES

The FDA Responder Endpoint for IBS-C clinical trials represents clinically meaningful improvements in IBS-C symptoms for patients with excellent specificity and reasonable sensitivity.

Diffusion tensor imaging detects microstructural reorganization in the brain associated with chronic irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by recurring abdominal pain associated with alterations in bowel habits. We hypothesized that patients with chronic visceral pain associated with IBS may have microstructural differences in the brain compared with healthy control subjects (HCs), indicative of long-term neural reorganization of chronic pain pathways and regions associated with sensory integration. In the current study we performed population-based voxel-wise diffusion tensor imaging (DTI) comparisons and probabilistic tractography in a large sample of phenotyped patients with IBS (n=33) and in HCs (n=93). Patients had lower fractional anisotropy (FA) in thalamic regions, the basal ganglia (BG) and sensory/motor association/integration regions as well as higher FA in frontal lobe regions and the corpus callosum. In addition, patients had reduced mean diffusivity (MD) within the globus pallidus (GP) and higher MD in the thalamus, internal capsule, and coronal radiata projecting to sensory/motor regions, suggestive of differential changes in axon/dendritic density in these regions. Sex differences in FA and MD were also observed in the patients but not in HCs. Probabilistic tractography in patients confirmed a higher degree of connectivity between the thalamus and prefrontal cortex, as well as between the medial dorsal thalamic nuclei and anterior cingulate cortex, and a lower degree of connectivity between the GP and thalamus. Together, these results support the hypothesis that patients with chronically recurring visceral pain from IBS have long-term microstructural changes within the brain, particularly in regions associated with integration of sensory information and corticothalamic modulation.

Digestive symptoms in older adults: prevalence and associations with institutionalization and mortality

BACKGROUND

Digestive symptoms are common in adults. However, little is known about their prevalence in older adults and the association of digestive symptoms with institutionalization and mortality in community-dwelling older adults.

OBJECTIVE

To determine the prevalence of digestive symptoms among older adults in Canada and whether they are associated with increased risk of institutionalization and mortality, independent of the effect of potential confounders.

METHODS

The present study was a secondary analysis of data collected from community-dwelling participants 65 years of age and older in the Canadian Study of Health and Aging. Measures incuded age, sex, presence of digestive symptoms, cognition, impairment in activities of daily living (ADL) and self-reported health. Outcome measures included death or institutionalization over the 10 years of follow-up.

RESULTS

Digestive symptoms were found in 2288 (25.6%) of the 8949 subjects. Those with digestive symptoms were older, with a mean difference in age of six months (P=0.007). Digestive symptoms were more common among women (28.4%) than men (20.3%), among individuals with poor self-reported health and those with an increased number of impairments in their ADLs (P<0.001). The presence of digestive symptoms was associated with higher mortality (HR 1.15 [95% CI 1.05 to 1.25] adjusted for age, sex, cognitive function and ADL impairment); however, this association was not statistically significant after adjusting for self-reported health.

CONCLUSION

Although digestive symptoms were associated with increased mortality independent of age and sex, cognition and function, this association was largely explained by poor self-assessed health. Digestive symptoms were not associated with institutionalization.

Visceral analgesia induced by acute and repeated water avoidance stress in rats: sex difference in opioid involvement

BACKGROUND

Chronic psychological stress-induced alterations in visceral sensitivity have been predominantly assessed in male rodents. We investigated the effect of acute and repeated water avoidance stress (WAS) on the visceromotor response (VMR) to colorectal distension (CRD) and the role of opioids in male and cycling female Wistar rats using a novel non-invasive manometric technique.

METHODS

After a baseline VMR (1st CRD, day 0), rats were exposed to WAS (1 h day(-1) ) either once or for four consecutive days, without injection or with naloxone (1 mg kg(-1) ) or saline injected subcutaneously before each WAS session.

KEY RESULTS

The VMR to CRD recorded on day 1 or 4 immediately after the last WAS was reduced in both females and males. The visceral analgesia was mainly naloxone-dependent in females, but naloxone-independent in males. In non-injected animals, on days 2 and 5, VMR was not significantly different from baseline in males whereas females exhibited a significant VMR increase at 60 mmHg on day 5. Basal CRD and CRD on days 1, 2, and 5 in both sexes without WAS induced similar VMR.

CONCLUSIONS & INFERENCES

  When monitored non-invasively, psychological stress induces an immediate poststress visceral analgesia mediated by an opiate signaling system in females while naloxone-independent in males, and hyperalgesia at 24 h after repeated stress only in females. These data highlight the importance of sex-specific interventions to modulate visceral pain response to stress.

Prevalence, comorbidity, and risk factors for functional bowel symptoms: a population-based survey in Northern Norway

OBJECTIVE

To assess the occurrence of functional bowel (FB) symptoms in Northern Norway, and to describe gender differences, comorbidity, and association to risk factors, including Helicobacter pylori infection.

MATERIALS AND METHODS

Adult subjects (18-85 years) from the communities Bodø and Sørreisa were invited to complete a questionnaire on gastrointestinal symptoms, and to provide stool samples for assessment of H. pylori.

RESULTS

Of 3927 invited subjects, 1731 (44.1%) responded to the questionnaire and 1416 (36.0%) provided stool samples. Functional bowel symptoms were found in 25%, somewhat more frequent in females (28.6%). Symptom pattern differed between genders only with regard to constipation. Presence of FB symptoms was significantly associated with gastroesophageal reflux symptoms, headache, dizziness, palpitations, sleep disturbances, and musculoskeletal symptoms. Psychometric traits were also more prevalent: feeling of low coping ability, feeling depressed, feeling of time pressure, and a low self-evaluation of health. In a multivariate regression model, factors that influenced the reporting FB symptoms were male gender (OR 0.71, 95% CI (0.52; 0.96)), age 50-69 years or ≥70 years (OR 0.49 (0.30; 0.80) and 0.40 (0.21; 0.79)), obesity (OR 1.61 (1.05; 2.47)), NSAID use (OR 2.50 (1.63; 3.83)), and previous abdominal surgery (OR 1.54 (1.05; 2.26)). The presence of H. pylori was not associated with FB symptoms.

CONCLUSIONS

Functional bowel symptoms are prevalent, but our findings may be prone to self-selection bias. FB symptoms carry a significant burden of comorbidity. Female gender and low age are known risk factors for FB symptoms, whereas NSAID use as a risk factor deserves further clarification.

Effects of personality traits on the manifestations of irritable bowel syndrome

Objective

Previous studies have reported that patients with irritable bowel syndrome (IBS) show high neuroticism. However, the precise association between the IBS subtypes and the degree of neuroticism in younger populations is largely unknown. We tested our hypothesis that subjects with diarrhea-predominant IBS may have a higher degree of neuroticism than subjects without IBS or those with other subtypes of IBS. We also verified the additional hypothesis that the severity of neuroticism might be correlated with the severity of IBS in younger populations.

Methods

We conducted a cross-sectional survey of 557 university students, ranging in age from 18 to 21 years. Presence/ absence of IBS and determination of the IBS subtype was by the Rome II Modular Questionnaire, while the severity of IBS was determined by the IBS severity index (IBS-SI). The degree of neuroticism was evaluated using the Maudsely Personality Inventory (MPI). The presence/absence of psychological distress was measured with the K6 scale.

Results

Neuroticism scores in the subjects with diarrhea-predominant IBS were significantly higher than those in the non-IBS subjects or subjects with constipation-predominant IBS. The neuroticism scores were significantly correlated with the IBS-SI scores in all subjects with IBS.

Conclusion

These results suggest that neuroticism is involved in the pathophysiology of IBS in young subjects, especially in that of the diarrhea-predominant subtype.

Alosetron: an effective treatment for diarrhea-predominant irritable bowel syndrome

Serotonin (5-HT) is one of the key mediators of gut motility, secretion and sensation. Most 5-HT is localized in the gastrointestinal tract. Particularly important for gut function and regulation are the 5-HT(1P), 5-HT(3) and 5-HT(4) receptors. These receptors have been the focus of research evaluating the pathophysiologic mechanisms of irritable bowel syndrome (IBS) as well as targets for the development of novel agents to treat irritable bowel syndrome. Alosetron is one of three 5-HT(3) antagonists currently available. The other two, ondansetron and granisetron, are primarily used in the treatment of chemotherapy-induced nausea and vomiting. Alosetron, which slows gut transit, has been approved for the treatment of severe diarrhea-predominant IBS (IBS-D) in women. This review will examine the common, yet therapeutically challenging, disorder IBS, as well as the role of alosetron in the treatment of IBS-D.

Sex differences in spinal processing of transient and inflammatory colorectal stimuli in the rat

Sex differences in the spinal processing of somatic and visceral stimuli contribute to greater female sensitivity in many pain disorders. The present study examined spinal mechanisms that contribute to sex differences in visceral sensitivity. The visceromotor response to colorectal distention (CRD) was more robust in normal female rats and after intracolonic mustard oil compared with that in male rats. No sex difference was observed in the CRD-evoked response of lumbosacral (LS) and thoracolumbar (TL) colonic afferents in normal and mustard oil-treated rats, but there was a sex difference in spontaneous activity that was exacerbated by intracolonic mustard oil. The response of visceroceptive dorsal horn neurons to CRD was greater in normal female rats in the LS and TL spinal segments. The effect of intracolonic mustard oil on the CRD-evoked response of different phenotypes of visceroceptive dorsal horn neurons was dependent on sex and segment. The NMDA receptor antagonist 2-amino-5-phosphonopentanoic acid (APV) dose-dependently attenuated the visceromotor response in normal rats with greater effect in male rats. Correspondingly, there was greater cell membrane expression of the GluN1 subunit in dorsal horn extracts in female rats. After intracolonic mustard oil, there was no longer a sex difference in the effect of APV nor GluN1 expression in LS segments, but greater female expression in TL segments. These data document a sex difference in spinal processing of nociceptive visceral stimuli from the normal and inflamed colon. Differences in dorsal horn neuronal activity and NMDA receptor expression contribute to the sex differences in the visceral sensitivity observed in awake rats.