Recollection of childhood events in adults with irritable bowel syndrome

Early Life Exposure to Food Contaminants and Social Stress as Risk Factor for Metabolic Disorders Occurrence?-An Overview

The global prevalence of obesity has been increasing in recent years and is now the major public health challenge worldwide. While the risks of developing metabolic disorders (MD) including obesity and type 2 diabetes (T2D) have been historically thought to be essentially driven by increased caloric intake and lack of exercise, this is insufficient to account for the observed changes in disease trends. Based on human epidemiological and pre-clinical experimental studies, this overview questioned the role of non-nutritional components as contributors to the epidemic of MD with a special emphasis on food contaminants and social stress. This overview examines the impact of early life adverse events (ELAE) focusing on exposures to food contaminants or social stress on weight gain and T2D occurrence in the offspring and explores potential mechanisms leading to MD in adulthood. Indeed, summing up data on both ELAE models in parallel allowed us to identify common patterns that appear worthwhile to study in MD etiology. This overview provides some evidence of a link between ELAE-induced intestinal barrier disruption, inflammation, epigenetic modifications, and the occurrence of MD. This overview sums up evidence that MD could have developmental origins and that ELAE are risk factors for MD at adulthood independently of nutritional status.

Psychological Stress, Intestinal Barrier Dysfunctions, and Autoimmune Disorders: An Overview

Autoimmune disorders (ADs) are multifactorial diseases involving, genetic, epigenetic, and environmental factors characterized by an inappropriate immune response toward self-antigens. In the past decades, there has been a continuous rise in the incidence of ADs, which cannot be explained by genetic factors alone. Influence of psychological stress on the development or the course of autoimmune disorders has been discussed for a long time. Indeed, based on epidemiological studies, stress has been suggested to precede AD occurrence and to exacerbate symptoms. Furthermore, compiling data showed that most of ADs are associated with gastrointestinal symptoms, that is, microbiota dysbiosis, intestinal hyperpermeability, and intestinal inflammation. Interestingly, social stress (acute or chronic, in adult or in neonate) is a well-described intestinal disrupting factor. Taken together, those observations question a potential role of stress-induced defect of the intestinal barrier in the onset and/or the course of ADs. In this review, we aim to present evidences supporting the hypothesis for a role of stress-induced intestinal barrier disruption in the onset and/or the course of ADs. We will mainly focus on autoimmune type 1 diabetes, multiple sclerosis and systemic lupus erythematosus, ADs for which we could find sufficient circumstantial data to support this hypothesis. We excluded gastrointestinal (GI) ADs like coeliac disease to privilege ADs not focused on intestinal disorders to avoid confounding factors. Indeed, GIADs are characterized by antibodies directed against intestinal barrier actors.

Clinical profile of comorbid dysmenorrhea and bladder sensitivity: a cross-sectional analysis

BACKGROUND

Antecedents of chronic pelvic pain are not well characterized, but pelvic organ visceral sensitivity is a hallmark of these disorders. Recent studies have identified that some dysmenorrhea sufferers are much more likely to exhibit comorbid bladder hypersensitivity. Presumably, these otherwise healthy women may be at higher risk of developing full-blown chronic bladder pain later in life. To encourage early identification of patients harboring potential future risk of chronic pain, we describe the clinical profile of women matching this putative pain-risk phenotype.

OBJECTIVE(S)

The objectives of the study were to characterize demographic, menstrual, pelvic examination, and psychosocial profiles of young women with comorbid dysmenorrhea and bladder hypersensitivity, defined using a standardized experimental visceral provocation test, contrasted with healthy controls, pure dysmenorrhea sufferers, and women with existing bladder pain syndrome.

STUDY DESIGN

This prospective cohort study acquired data on participants with moderate to severe dysmenorrhea (n = 212), healthy controls (n = 44), and bladder pain syndrome (n = 27). A subgroup of dysmenorrhea patients was found on screening with noninvasive oral water challenge to report significantly higher bladder pain during experimentally monitored spontaneous bladder filling (>15 out of 100 on visual analogue scale, based on prior validation studies) and separately defined as a group with dysmenorrhea plus bladder pain. Medical/menstrual history and pain history were evaluated with questionnaires. Psychosocial profile and impact were measured with validated self-reported health status Patient Reported Outcomes Measurement Information System short forms and a Brief Symptom Inventory for somatic sensitivity. Pelvic anatomy and sensory sensitivity were examined via a standardized physical examination and a tampon provocation test.

RESULTS

In our largely young, single, nulliparous cohort (24 ± 1 years old), approximately a quarter (46 out of 212) of dysmenorrhea sufferers tested positive for the dysmenorrhea plus bladder pain phenotype. Dysmenorrhea-only sufferers were more likely to be African American (24%) than healthy controls (5%, post hoc χ², P = .007). Pelvic examination findings did not differ in the nonchronic pain groups, except for tampon test sensitivity, which was worse in dysmenorrhea plus bladder pain and dysmenorrhea sufferers vs healthy controls (2.6 ± 0.3 and 1.7 ± 0.2 vs 0.7 ± 0.2, P < .05). Consistent with heightened pelvic sensitivity, participants with dysmenorrhea plus bladder pain also had more nonmenstrual pain, dysuria, dyschezia, and dyspareunia (P's < .05). Participants with dysmenorrhea plus bladder pain had Patient Reported Outcomes Measurement Information System Global Physical T-scores of 47.7 ± 0.9, lower than in women with dysmenorrhea only (52.3 ± 0.5), and healthy controls 56.1 ± 0.7 (P < .001). Similarly, they had lower Patient Reported Outcomes Measurement Information System Global Mental T-score than healthy controls (47.8 ± 1.1 vs 52.8 ± 1.2, P = .017). Similar specific impairments were observed on Patient Reported Outcomes Measurement Information System scales for anxiety, depression, and sleep in participants with dysmenorrhea plus bladder pain vs healthy controls.

CONCLUSION

Women with dysmenorrhea who are unaware they also have bladder sensitivity exhibit broad somatic sensitivity and elevated psychological distress, suggesting combined preclinical visceral sensitivity may be a precursor to chronic pelvic pain. Defining such precursor states is essential to conceptualize and test preventative interventions for chronic pelvic pain emergence. Dysmenorrhea plus bladder pain is also associated with higher self-reported pelvic pain unrelated to menses, suggesting central nervous system changes are present in this potential precursor state.

A Systematic Review of Somatic Symptoms in Children With a Chronically Ill Family Member

OBJECTIVE

Somatization and functional somatic symptoms reflect conditions in which physical symptoms are not sufficiently explained by medical conditions. Literature suggests that these somatic symptoms may be related to illness exposure in the family. Children with a parent or sibling with a chronic illness may be particularly vulnerable to developing somatic symptoms. This study provides a systematic review of the literature on somatic symptoms in children with a chronically ill family member.

METHODS

A systematic review (PROSPERO registry ID: CRD42018092344) was conducted using six databases (PubMed, EMBASE, PsychINFO, Scopus, CINAHL, and Cochrane) from articles published before April 5, 2018. All authors evaluated articles by title and abstract, and then by full-text review. Relevant data were extracted by the first author and reviewed by remaining authors.

RESULTS

Twenty-seven unique studies met the criteria. Seventeen examined somatic symptoms in children with a chronically ill parent, and seven evaluated somatic symptoms in children with a chronically ill sibling. Three studies examined somatic symptoms in children with an unspecified ill relative. The strongest relationship between child somatization and familial illness was found with children with a chronically ill parent (13/17 studies). Evidence for somatic symptoms in children with an ill sibling was mixed (4/7 studies found a positive association).

CONCLUSIONS

The literature on somatic symptoms in children suggests that parental illness is related to increased somatic symptoms in children. Research examining the effects of having a sibling with an illness on somatic symptoms is mixed. Several areas of future research are outlined to further clarify the relationship between familial chronic illness and somatic symptoms.

The Therapeutic Effect of Exercise on Anxiety and Bowel Oxidative Stress in the Maternal Separation Animal Model

Introduction:

According to evidence, Early-Life Stress (ELS), mood disorders, and medical comorbidities, i.e. Irritable Bowel Syndrome (IBS), are correlated; however, the direct contribution of ELS to IBS manifestations is less understood. The current study aimed at evaluating the effect of voluntary exercise on the mitochondrial dysfunction of the bowel fibroblasts, following the confirmation of anxiety behavior.

Methods:

In this study, Postnatal Day (PND) rats underwent Maternal Separation (MS), as a valid animal model of the brain-gut axis dysfunction, in the days 2–14; three hours daily. On day 21, the study animals were divided into 4 groups, as follows: control, Running Wheel (RW) exercise, MS, and MS+RW groups. The study groups were housed in separate cages (4 rats per cage) until the onset of intervention. On day 60, the elevated plusmaze was used to assess anxiety-like behaviors; the level of oxidative stress biomarkers, i.e. Reactive Oxygen Species (ROS), Glutathione (GSH), as well as Adenosine Triphosphate (ATP) was measured to determine the gut mitochondrial function.

Results:

Findings revealed that ELS affected the gut energy metabolism in the studied rats; the negative effects of MS on anxiety and the gut mitochondrial dysfunction decreased via RW exercise during adolescence.

Conclusion:

Overall, anxiety behaviors and ROS production, leading to increased GSH and ATP levels, improved after RW exercise; this significantly impacts the function of colon secretory mitochondria. According to the positive effects of RW exercise on mitochondrial dysfunction in an ELS animal model, a potential relationship was found between the brain and gut in the study rats.

Early life stress in mice is a suitable model for Irritable Bowel Syndrome but does not predispose to colitis nor increase susceptibility to enteric infections

Neonatal period is characterized by an immature intestinal barrier. Scattered evidence suggests that early life stressful events induce long lasting alterations of intestinal homeostasis mimicking Irritable Bowel Syndrome (IBS). Those observations highlighting defect of intestinal barrier by early life stress questioned its potential role as a risk factor for gastrointestinal disorders such as colitis and infections. In this study, we aimed to analyze if maternal separation (MS) in mice mimicks IBS main features. We next addressed whether MS could trigger or exacerbate colitis in genetically predisposed mice and/or enhance susceptibility to gastrointestinal infections in wild type mice. MS induced main features of IBS in adult wild type male mice i.e. intestinal hyperpermeability, visceral hypersensitivity, microbiota dysbiosis, bile acid malabsorption and low grade inflammation in intestine associated with a defect of Paneth cells and the ILC3 population. This breach in mucosal barrier functions in adults was associated with a systemic IgG response against commensal E. coli and increased IFNγ secretion by splenocytes. However, in IL10^-/- mice, MS did not trigger nor worsen colitis. Furthermore, wild type mice submitted to MS did not show increase susceptibility to gastrointestinal infections (S. Typhimurium, L. monocytogenes or T. gondii) compared to controls. Altogether, our results identify MS in mice as a good experimental model for IBS mimicking all the main features. In addition, early life stress, even though it has long lasting consequences on intestinal homeostasis, does not constitute a facilitating factor to colitis in predisposed individuals nor to gastrointestinal infections in wild type mice.

Do Children Just Grow Out of Irritable Bowel Syndrome?

OBJECTIVE

Few data exist on natural history of irritable bowel syndrome (IBS) in children; therefore we investigated symptoms evolution over time in a cohort of children with IBS.

STUDY DESIGN

In this observational, single-center study, we prospectively enrolled newly diagnosed children with IBS and reassessed them after 24 months. At both time points, patients completed a symptoms questionnaire, and a score of stool consistency was obtained. The therapeutic strategy adopted was also recorded.

RESULTS

Eighty-three children (age 11 years, range, 4-16.6 years; 53 males) completed the study. Forty-seven (56.6%) patients received no medical treatment, whereas polyethylene glycol, probiotics, and trimebutine were prescribed to 9 (10.8%), 24 (28.9%), and 3 (3.6%) subjects, respectively. Twenty-four months after diagnosis, 48 children (57.8%) reported resolution of symptoms (P <.001), without differences between sexes (P = .35) or among IBS subtypes (P = .49). Of these, 30 (62.5%) had been only reassured and 18 (37.5%) had been prescribed medical treatment (P = .26). Despite not being statistically significant, symptoms resolution was more common in patients receiving no medical treatment than in those receiving probiotics (63.8% vs 41.6%, P = .08). Among patients with constipation-IBS, no difference was found in symptoms resolution between patients receiving polyethylene glycol and those receiving no medical treatment (67% and 40%, respectively, P = 1).

CONCLUSIONS

Children with IBS are likely to show spontaneous symptoms resolution over a 24-month follow-up, regardless of sex, age, impact of symptoms on daily activities, and IBS subtypes.

Psychosocial mechanisms for the transmission of somatic symptoms from parents to children

AIM

To examine familial aggregation of irritable bowel syndrome (IBS) via parental reinforcement/modeling of symptoms, coping, psychological distress, and exposure to stress.

METHODS

Mothers of children between the ages of 8 and 15 years with and without IBS were identified through the Group Health Cooperative of Puget Sound. Mothers completed questionnaires, including the Child Behavior Checklist (child psychological distress), the Family Inventory of Life Events (family exposure to stress), SCL-90R (mother psychological distress), and the Pain Response Inventory (beliefs about pain). Children were interviewed separately from their parents and completed the Pain Beliefs Questionnaire (beliefs about pain), Pain Response Inventory (coping) and Child Symptom Checklist [gastrointestinal (GI) symptoms]. In addition, health care utilization data was obtained from the automated database of Group Health Cooperative. Mothers with IBS (n = 207) and their 296 children were compared to 240 control mothers and their 335 children, while controlling for age and education.

RESULTS

Hypothesis 1: reinforcement of expression of GI problems is only related to GI symptoms, but not others (cold symptoms) in children. There was no significant correlation between parental reinforcement of symptoms and child expression of GI or other symptoms. Hypothesis 2: modeling of GI symptoms is related to GI but not non-GI symptom reporting in children. Children of parents with IBS reported more non-GI (8.97 vs 6.70, P < 0.01) as well as more GI (3.24 vs 2.27, P < 0.01) symptoms. Total health care visits made by the mother correlated with visits made by the child (rho = 0.35, P < 0.001 for cases, rho = 0.26, P < 0.001 for controls). Hypothesis 3: children learn to share the methods of coping with illness that their mothers exhibit. Methods used by children to cope with stomachaches differed from methods used by their mothers. Only 2/16 scales showed weak but significant correlations (stoicism rho = 0.13, P < 0.05; acceptance rho = 0.13, P < 0.05). Hypothesis 4: mothers and children share psychological traits such as anxiety, depression, and somatization. Child psychological distress correlated with mother's psychological distress (rho = 0.41, P < 0.001 for cases, rho= 0.38, P < 0.001 for controls). Hypothesis 5: stress that affects the whole family might explain the similarities between mothers and their children. Family exposure to stress was not a significant predictor of children's symptom reports. Hypothesis 6: the intergenerational transmission of GI illness behavior may be due to multiple mechanisms. Regression analysis identified multiple independent predictors of the child's GI complaints, which were similar to the predictors of the child's non-GI symptoms (mother's IBS status, child psychological symptoms, child catastrophizing, and child age).

CONCLUSION

Multiple factors influence the reporting of children's gastrointestinal and non-gastrointestinal symptoms. The clustering of illness within families is best understood using a model that incorporates all these factors.

Adult bone strength of children from single-parent families: the Midlife in the United States Study

Bone health may be negatively impacted by childhood socio-environmental circumstances. We examined the independent associations of single-parent childhood and parental death or divorce in childhood with adult bone strength indices. Longer exposure to a single-parent household in childhood was associated with lower bone strength in adulthood.

INTRODUCTION

Because peak bone mass is acquired during childhood, bone health may be negatively impacted by childhood socio-environmental disadvantage. The goal of this study was to determine whether being raised in a single-parent household is associated with lower bone strength in adulthood.

METHODS

Using dual-energy X-ray absorptiometry data from 708 participants (mean age 57 years) in the Midlife in the United States Biomarker Project, we examined the independent associations of composite indices of femoral neck bone strength relative to load (in three failure modes: compression, bending, and impact) in adulthood with the experience of single-parent childhood and parental death or divorce in childhood.

RESULTS

After adjustment for gender, race, menopause transition stage, age, and body mass index, each additional year of single-parent childhood was associated with 0.02 to 0.03 SD lower indices of adult femoral neck strength. In those with 9-16 years of single-parent childhood, the compression strength index was 0.41 SD lower, bending strength index was 0.31 SD lower, and impact strength index was 0.25 SD lower (all p values < 0.05). In contrast, parental death or divorce during childhood was not by itself independently associated with adult bone strength indices. The magnitudes of these associations were unaltered by additional adjustment for lifestyle factors and socioeconomic status in childhood and adulthood.

CONCLUSIONS

Independent of parental death or divorce, growing up in a single-parent household is associated with lower femoral neck bone strength in adulthood, and this association is not entirely explained by childhood or adult socioeconomic conditions or lifestyle choices.

Psychosocial factors and central sensitivity syndromes

Central sensitivity syndromes (CSSs) represent a heterogeneous group of disorders (e.g., fibromyalgia [FM], irritable bowel syndrome [IBS], chronic headache, temporomandibular disorders [TMDs], pelvic pain syndromes) that share many common symptoms, with persistent pain being the most prominent feature. Although the etiology and pathophysiology of CSSs are currently incompletely understood, central sensitization has emerged as one of the significant mechanisms. Given that there are currently no known cures for CSSs, people living with these disorders must learn to cope with and manage their symptoms throughout their lives. Medical interventions alone have not proven to be sufficient for helping people with CSSs manage their symptoms. A biopsychosocial perspective that considers the ways that biological, psychological, and social factors work independently and jointly to affect a person's experience is the most effective conceptualization and guide for effective treatment. In this article, we discuss several psychological and social features that may influence the experience of a person with CSS and their symptom management, regardless of their specific diagnosis. We highlight the longitudinal aspect of adjustment to illness, the distinction between psychosocial factors as causes of symptoms versus modifiers and perpetuators of symptoms, dispel the notion that all patients with the same diagnosis are a homogeneous group (the "patient-uniformity myth"), and acknowledge the importance of environmental and situational context on symptom management for individuals with any CSS.

Irritable bowel syndrome: The evolution of multi-dimensional looking and multidisciplinary treatments

Irritable bowel syndrome (IBS) is common in the society. Among the putative pathogeneses, gut dysmotility results in pain and disturbed defecation. The latter is probably caused by the effect of abnormal gut water secretion. The interaction between abnormal gas accumulation, abdominal pain and bloating remains controversial. Visceral hypersensitivity and its modification along with the central transmission are the characteristics of IBS patients. The identification of biologic markers based on genetic polymorphisms is undetermined. Imbalanced gut microbiota may alter epithelial permeability to activate nociceptive sensory pathways which in turn lead to IBS. Certain food constituents may exacerbate bowel symptoms. The impact of adult and childhood abuses on IBS is underestimated. Using the concept of biopsychosocial dysfunction can integrate multidimensional pathogeneses. Antispasmodics plus stool consistency modifiers to treat the major symptoms and defecation are the first-line drug treatment. New drugs targeting receptors governing bowel motility, sensation and secretion can be considered, but clinicians must be aware of their potential serious side effects. Psychiatric drugs and modalities may be the final options for treating intractable subjects. Probiotics of multi-species preparations are safe and worth to be considered for the treatment. Antibiotics are promising but their long-term safety and effectiveness are unknown. Diet therapy including exclusion of certain food constituents is an economic measure. Using relatively safe complementary and alternative medicines (CAMs) may be optional to those patients who failed classical treatment. In conclusion, IBS is a heterogeneous disorder with multidimensional pathogeneses. Personalized medicines with multidisciplinary approaches using different classes of drugs, psychiatric measures, probiotics and antibiotics, dietary therapy, and finally CAMs, can be considered.

Unpredictable neonatal stress enhances adult anxiety and alters amygdala gene expression related to serotonin and GABA

Anxiety-related disorders are among the most common psychiatric illnesses, thought to have both genetic and environmental causes. Early-life trauma, such as abuse from a caregiver, can be predictable or unpredictable, each resulting in increased prevalence and severity of a unique set of disorders. In this study, we examined the influence of early unpredictable trauma on both the behavioral expression of adult anxiety and gene expression within the amygdala. Neonatal rats were exposed to unpaired odor-shock conditioning for 5 days, which produces deficits in adult behavior and amygdala dysfunction. In adulthood, we used the Light/Dark box test to measure anxiety-related behaviors, measuring the latency to enter the lit area and quantified urination and defecation. The amygdala was then dissected and a microarray analysis was performed to examine changes in gene expression. Animals that had received early unpredictable trauma displayed significantly longer latencies to enter the lit area and more defecation and urination. The microarray analysis revealed over-represented genes related to learning and memory, synaptic transmission and trans-membrane transport. Gene ontology and pathway analysis identified highly represented disease states related to anxiety phenotypes, including social anxiety, obsessive-compulsive disorders, post-traumatic stress disorder and bipolar disorder. Addiction-related genes were also overrepresented in this analysis. Unpredictable shock during early development increased anxiety-like behaviors in adulthood with concomitant changes in genes related to neurotransmission, resulting in gene expression patterns similar to anxiety-related psychiatric disorders.

Natural history of irritable bowel syndrome

BACKGROUND

Chronic diarrhea and functional abdominal pain (FAP) in childhood could be an early manifestation of adult irritable bowel syndrome (IBS). The aim of this study was to investigate the presence of chronic functional digestive symptoms in childhood, interviewing adult patients diagnosed with IBS, in an attempt to establish a relationship between them.

METHODS

By means of a questionnaire, the history of colic, chronic diarrhea, functional abdominal pain, constipation and migraine in childhood, was analyzed in patients diagnosed with IBS according to the current Rome III criteria, and in control patients without known chronic digestive disorders. Fisher's exact test was used for comparison of frequencies.

RESULTS

The IBS study group was made up of 40 patients (24 women; average age, 33.03 years), and the control group by 40 adults (22 women; average age, 29.62 years). IBS-diagnosed adults spoke about a significantly higher prevalence of chronic diarrhea (32.5/7.5%; odds ratio [OR], 7.01; 95% confidence interval [CI]: 26.84-1.80), and FAP (37.5/15%; OR, 4.30; 95%CI: 12.67-1.43) in their childhood, than the control group. There were no differences in the presence of other childhood functional symptoms. Interestingly, the present patients, when asked about the onset of symptoms that led to the diagnosis of IBS, referred to them mostly beginning in adulthood, not linking their current diagnosis of IBS with their background in childhood.

CONCLUSIONS

In a proportion of adults with IBS the natural history of their symptoms probably began during their childhood.

Life course study of the etiology of self-reported irritable bowel syndrome in the 1958 British birth cohort

OBJECTIVE

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder with unknown etiology. This is the first study to use a life course approach to examine premorbid risk markers for self-reported IBS in a UK birth cohort.

METHODS

Cohort study using the 1958 British birth cohort, which included 98.7% of births in 1 week in England, Wales, and Scotland. The outcome was self-reported IBS by the age of 42 years, classified with onset after 24 years and onset after 34 years. Childhood psychopathology was assessed by the Rutter scales, and adulthood psychopathology was assessed by the Malaise Inventory.

RESULTS

The prevalence of self-reported IBS in this cohort was 8.4% by 42 years (95% confidence interval [CI]=8.2-8.6). In multivariate analyses, being female (odds ratio [OR]=2.00, 95% CI=1.67-2.36), reporting 1 week to 1 month of school absence for ill health at 16 years (OR=1.27, 95% CI=1.03-1.56) and psychopathology at 23 years (OR=1.25, 95% CI=1.01-1.54) and 33 years (OR=2.20, 95% CI=1.74-2.76) were associated with an increased odds for IBS. Prospectively measured childhood adversity showed no significant association.

CONCLUSIONS

This is the first study to show a long-term prospective link between premorbid psychopathology and later self-reported IBS, in agreement with previous findings on chronic fatigue syndrome. There is no evidence that prospective measures of childhood adversity are risk markers for IBS, and there is weak evidence that prospective measures of childhood illness at 16 years are risk markers for IBS, differing to results from the same cohort for psychopathology, chronic fatigue syndrome, and chronic widespread pain. This study also does not replicate the findings of retrospective studies examining the etiology of IBS.

Irritable bowel syndrome: Diagnosis and pathogenesis

Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) disorder that considerably reduces the quality of life. It further represents an economic burden on society due to the high consumption of healthcare resources and the non-productivity of IBS patients. The diagnosis of IBS is based on symptom assessment and the Rome III criteria. A combination of the Rome III criteria, a physical examination, blood tests, gastroscopy and colonoscopy with biopsies is believed to be necessary for diagnosis. Duodenal chromogranin A cell density is a promising biomarker for the diagnosis of IBS. The pathogenesis of IBS seems to be multifactorial, with the following factors playing a central role in the pathogenesis of IBS: heritability and genetics, dietary/intestinal microbiota, low-grade inflammation, and disturbances in the neuroendocrine system (NES) of the gut. One hypothesis proposes that the cause of IBS is an altered NES, which would cause abnormal GI motility, secretions and sensation. All of these abnormalities are characteristic of IBS. Alterations in the NES could be the result of one or more of the following: genetic factors, dietary intake, intestinal flora, or low-grade inflammation. Post-infectious IBS (PI-IBS) and inflammatory bowel disease-associated IBS (IBD-IBS) represent a considerable subset of IBS cases. Patients with PI- and IBD-IBS exhibit low-grade mucosal inflammation, as well as abnormalities in the NES of the gut.

Pathways to lifespan health following childhood parental death

The death of a parent is a profoundly stressful form of childhood adversity, increasing the short- and long-term risk of mental health problems. Emerging research suggests it may also disrupt biological regulatory systems and increase the risk of long-term physical health problems. This article presents a theoretical framework of the process by which the experience of parental death during childhood may influence mental and physical health outcomes over time. Drawing from a broad literature on adaptation following childhood parental loss, we focus on risk and protective factors in the childhood environment that are theoretically and empirically linked to emotional and biological regulatory responses to stress later in life, the effects of which may accumulate to impact long-term health.

Do interactions between stress and immune responses lead to symptom exacerbations in irritable bowel syndrome?

Irritable bowel syndrome (IBS) is a common, debilitating gastrointestinal (GI) disorder, with a worldwide prevalence of between 10% and 20%. This functional gut disorder is characterized by episodic exacerbations of a cluster of symptoms including abdominal pain, bloating and altered bowel habit, including diarrhea and/or constipation. Risk factors for the development of IBS include a family history of the disorder, childhood trauma and prior gastrointestinal infection. It is generally accepted that brain-gut axis dysfunction is fundamental to the development of IBS; however the underlying pathophysiological mechanisms remain elusive. Additional considerations in comprehending the chronic relapsing pattern that typifies IBS symptoms are the effects of both psychosocial and infection-related stresses. Indeed, co-morbidity with mood disorders such as depression and anxiety is common in IBS. Accumulating evidence points to a role for a maladaptive stress response in the initiation, persistence and severity of IBS-associated symptom flare-ups. Moreover, mechanistically, the stress-induced secretion of corticotropin-releasing factor (CRF) is known to mediate changes in GI function. Activation of the immune system also appears to be important in the generation of IBS symptoms and increasing evidence now implicates low-grade inflammation or immune activation in IBS pathophysiology. There is a growing body of research focused on understanding at a molecular, cellular and in vivo level, the relationship between the dysregulated stress response and immune system alterations (either individually or in combination) in the etiology of IBS and to the occurrence of symptoms.

Lessons Learnt from Post-Infectious IBS

The development of IBS symptoms – altered bowel function and abdominal cramping in a subset of adult subjects exposed to severe enteric infections opened up an unprecedented opportunity to understand the etiology of this poorly understood disorder. Perhaps, for the reasons that these symptoms follow a severe enteric infection, and mucosal biopsy tissues are readily available, the focus of most studies thus far has been to show that mild/low-grade mucosal inflammation persisting after the initial infection has subsided causes the IBS symptoms. Parallel studies in non-infectious IBS patients, who did not have prior enteritis, showed similar mild mucosal inflammation. Together, these studies examined the mucosal infiltration of specific immune cells, increase of select inflammatory mediators, mast cell and enterochromaffin cell hyperplasia, and epithelial permeability. In spite of the fact that the data on these topics were not consistent among different studies and clinical trials with prednisone, fluoxetine, and ketotifen failed to provide relief of IBS symptoms, the predominant conclusions were that mild mucosal inflammation is the cause of IBS symptoms. However, the circular smooth muscle cells, and myenteric neurons are the primary regulators of gut motility function, while primary afferent neurons and CNS play essential roles in induction of visceral hypersensitivity – no explanation was provided as to how mild mucosal inflammation causes dysfunction in cells far removed. Accumulating evidence shows that mild mucosal inflammation in IBS patients is in physiological range. It has little deleterious effects on cells within its own environment and therefore it is unlikely to affect cells in the muscularis externa. This review discusses the disconnect between the focus on mild/low-grade mucosal inflammation and the potential mechanisms and molecular dysfunctions in smooth muscle cells, myenteric neurons, and primary afferent neurons that may underlie IBS symptoms.

Lessons Learnt from Post-Infectious IBS

The development of IBS symptoms - altered bowel function and abdominal cramping in a subset of adult subjects exposed to severe enteric infections opened up an unprecedented opportunity to understand the etiology of this poorly understood disorder. Perhaps, for the reasons that these symptoms follow a severe enteric infection, and mucosal biopsy tissues are readily available, the focus of most studies thus far has been to show that mild/low-grade mucosal inflammation persisting after the initial infection has subsided causes the IBS symptoms. Parallel studies in non-infectious IBS patients, who did not have prior enteritis, showed similar mild mucosal inflammation. Together, these studies examined the mucosal infiltration of specific immune cells, increase of select inflammatory mediators, mast cell and enterochromaffin cell hyperplasia, and epithelial permeability. In spite of the fact that the data on these topics were not consistent among different studies and clinical trials with prednisone, fluoxetine, and ketotifen failed to provide relief of IBS symptoms, the predominant conclusions were that mild mucosal inflammation is the cause of IBS symptoms. However, the circular smooth muscle cells, and myenteric neurons are the primary regulators of gut motility function, while primary afferent neurons and CNS play essential roles in induction of visceral hypersensitivity - no explanation was provided as to how mild mucosal inflammation causes dysfunction in cells far removed. Accumulating evidence shows that mild mucosal inflammation in IBS patients is in physiological range. It has little deleterious effects on cells within its own environment and therefore it is unlikely to affect cells in the muscularis externa. This review discusses the disconnect between the focus on mild/low-grade mucosal inflammation and the potential mechanisms and molecular dysfunctions in smooth muscle cells, myenteric neurons, and primary afferent neurons that may underlie IBS symptoms.

Exploring the intergenerational transmission of illness behavior: from observations to experimental intervention

BACKGROUND

Functional abdominal pain (FAP) of childhood is characterized by, among other things, pain with no known physiological cause, and family patterns of related disorders have been reported.

PURPOSE

The purpose of this paper is to trace the development of one FAP research program and highlight some of its key findings from observations of interaction patterns to intervention studies designed to test outcomes of altering these patterns.

METHODS

Studies summarized include observational and experimental research.

RESULTS

Parental response to child pain behaviors appears to be a key factor in the development and maintenance of FAP, and intervention which includes targeting changes in parental responses can decrease reports of pain and other illness behaviors.

CONCLUSIONS

Research into FAP can provide valuable information for not only FAP and other unexplained pain conditions, but other medical conditions where environmental responses may play an important role in their etiology and maintenance.

Combined effect of early life stress and acute stress on colonic sensory and motor responses through serotonin pathways: differences between proximal and distal colon in rats

Clinically, adults who have experienced stresses in childhood present with episodes of serious symptoms of irritable bowel syndrome that are associated with acute stress, but the mechanism is not well understood. This study aimed to investigate the colonic sensory/motor responses to acute water avoidance stress (WAS) in male adult rats subjected to neonatal maternal separation (NMS), and the underlying mechanism of sensory/motor responses. Effects of the combined acute and early life stress on visceral sensation, colonic motility, and the tissue and luminal content of serotonin (5-hydroxytryptamine, 5-HT) in the proximal and distal colon were evaluated using the abdominal withdrawal reflex test, faecal pellet output measurement and capillary electrophoresis analysis, respectively. Results showed that WAS significantly increased not only visceral sensitivity but also colonic motility in NMS rats compared to the normal rats. These alterations were accompanied by significant increase in 5-HT content in the proximal but not the distal colonic tissues; these alterations were also associated with increased density of enterochromaffin (EC) cells in the proximal segment. In contrast, the faecal content of 5-HT increased similarly in both segments. Consecutive administration of parachlorophenylalanine to NMS rats was more potent at 500 mg kg⁻¹ day⁻¹ than at 150 mg kg⁻¹ day⁻¹ in suppressing colonic sensory/motor responses to WAS, corresponding to the greater reduction of the tissue and faecal content of 5-HT and of EC cell density in the colon. These data indicate that combined early life stress and acute stress effectively induce visceral hyperalgesia and motility disorder through 5-HT pathways in the colon of rats, and the proximal and distal colon have different responses towards the combined stressors.

Do Parents Maintain or Exacerbate Pediatric Functional Abdominal Pain? A Systematic Review and Meta-analysis

Parents may maintain or exacerbate functional abdominal pain (FAP) in children through modeling of physical symptoms and solicitous responses to the child’s complaints. This systematic review and meta-analysis aimed to examine these relationships. Parents of children with FAP reported more physical symptoms than parents of healthy children (effect size d = .36). As all studies were cross-sectional or retrospective, the causal direction was unclear. For parental responses to child complaints, not enough studies were available to perform a meta-analysis. We conclude that the present literature is unfit to establish whether parents maintain or exacerbate pediatric FAP through the processes investigated.

The effects of gabapentin in two animal models of co-morbid anxiety and visceral hypersensitivity

Visceral hypersensitivity and an increased response to stress are two of the main symptoms of irritable bowel syndrome. Thus efforts to develop animal models of irritable bowel syndrome have centred on both of these parameters. The anticonvulsant gabapentin, which is widely used as an analgesic agent, also reduces anxiety. No data exists to our knowledge of the effects of gabapentin in animal models of co-morbid exaggerated stress response and visceral pain. Our aim was to assess the effect of gabapentin on stress and visceral hypersensitivity in two different animal models of irritable bowel syndrome. The animal models employed were the genetically susceptible Wistar Kyoto rat and the neonatally stressed maternal separation model. These animals were subjected to the open field paradigm to assess stress-induced defecation rates and colorectal distension to assess the level of visceral sensitivity. Gabapentin (30 mg/kg) prevented the stress-induced increase in faecal pellet output in the maternally separated rat, but not the Wistar Kyoto animals. On the other hand gabapentin (30 mg/kg) reduced the number of pain behaviours in response to colorectal distension in both models. These results show that whilst both models have similar responses to gabapentin in terms of visceral pain they differ in terms of their physiological response to stress. This indicates that the origin of anxiety and perhaps then visceral hypersensitivity differs in these models. Overall, these data suggest that gabapentin may be a useful treatment in disorders of co-morbid pain and an overactive stress system such as irritable bowel syndrome.

Functional abdominal pain and irritable bowel syndrome in children and adolescents

Functional abdominal pain (FAP) and irritable bowel syndrome (IBS) are both associated with recurrent abdominal pain and are among the most commonly diagnosed medical problems in pediatrics. The majority of patients with mild complaints improve with reassurance and time. For a distinct subset of patients with more severe and disabling illness, finding effective treatment for these disorders remains a challenge. Based on the biopsychosocial model of functional disease, the Rome III criteria have helped frame FAP and IBS in terms of being a positive diagnosis and not a diagnosis of exclusion. However, the lack of a single, proven intervention highlights the complex interplay of pathologic mechanisms likely involved in the development of childhood FAP and IBS and the need for a multidisciplinary, integrated approach. This article discusses the epidemiology, proposed mechanisms, clinical approach and therapeutic options for the management of FAP and IBS in children and adolescents.

The role of genetics in IBS

Irritable bowel syndrome (IBS) is a common disorder that has been shown to aggregate in families and to affect multiple generations, but not in a manner consistent with a major Mendelian effect. Relatives of an individual with IBS are 2 to 3 times as likely to have IBS, with both genders being affected. To date, more than 100 genetic variants in more than 60 genes from various pathways have been studied in a number of candidate gene studies, with several positive associations reported. These findings suggest that there may be distinct, as well as shared, molecular underpinnings for IBS and its subtypes.

Riluzole normalizes early-life stress-induced visceral hypersensitivity in rats: role of spinal glutamate reuptake mechanisms

BACKGROUND & AIMS

The molecular basis underlying visceral hypersensitivity in functional irritable bowel syndrome remains elusive, resulting in poor treatment effectiveness. Because alterations in spinal non-neuronal (astrocytic) glutamate reuptake are suspected to participate in chronic pain, we asked whether such processes occur in visceral hypersensitivity.

METHODS

Visceral hypersensitivity was induced in Sprague-Dawley rats by maternal separation. Separated adults were given a systemic administration of riluzole (5 mg/kg), an approved neuroprotective agent activating glutamate reuptake. Visceral hypersensitivity was assessed using colorectal distension (40 mm Hg). Somatic nociception was quantified using Hot Plate, Randall-Sellito, and Hargreaves tests. Spinal proteins were quantified using immunofluorescence and Western blot. The dependence of visceral sensory function upon spinal glutamate transport was evaluated by intrathecal injection of glutamate transport antagonist DL-threo-beta-benzyloxyaspartate (TBOA). For in vitro testing of riluzole and TBOA, primary cultures of astrocytes were used.

RESULTS

We show that riluzole counteracts stress-induced visceral hypersensitivity without affecting visceral response in nonseparated rats or altering nociceptive responses to somatic pain stimulation. In addition, maternal separation produces a reduction in glial excitatory amino acid transporter (EAAT)-1 with no change in EAAT-2 or gamma-amino butyric acid transporters. Stress was not associated with changes in glial fibrillary acidic protein or astrocytic morphology per se. Furthermore, visceral normosensitivity relies on spinal EAAT, as intrathecal TBOA is sufficient to induce hypersensitivity in normal rats.

CONCLUSIONS

We identify spinal EAAT as a therapeutic target, and establish riluzole as a candidate to counteract gastrointestinal hypersensitivity in disorders such as irritable bowel syndrome.

Distinct alterations in colonic morphology and physiology in two rat models of enhanced stress-induced anxiety and depression-like behaviour

Stress and anxiety are important causal and exacerbating factors in functional gastro-intestinal (GI) disorders such as irritable bowel syndrome. Stress affects GI motility, faecal transit and visceral pain sensitivity. Additionally, permeability and function of the gut epithelium, which acts as a barrier between the external environment and the body's internal milieu is altered by stress. However, the effects of an enhanced stress response on colonic morphology require further investigation. We have used two animal models of stress and anxiety, the maternally separated (MS) and Wistar Kyoto (WKY) rats to examine colonic morphology. These rats exhibit increased anxiety behaviours, visceral hypersensitivity and increased stress-induced defecation in the open field arena. At a morphological level, increased mucus secretion and an associated elevation in the number of mucosal goblet cells was observed in the high anxiety rats. Additionally, the mucosal layer was flattened in MS and WKY rats, a finding indicative of mild mucosal damage. Furthermore, the muscular layer of the distal colon in these animals was thickened, an observation that may have implications for faecal transit and visceral pain perception. This study provides evidence of altered colonic function and morphology in two animal models with a heightened response to stress.

Acute stress increases colonic paracellular permeability in mice through a mast cell-independent mechanism: involvement of pancreatic trypsin

AIMS

Increased colonic paracellular permeability (CPP) is a key feature of gastro-intestinal disorders as irritable bowel syndrome and inflammatory bowel diseases. Stress stimulates exocrine pancreatic secretion through cholinergic pathways, and trypsin is known to increase CPP. Consequently we have investigated in this work whether trypsin released into the gut lumen following an acute stress may participate to the short-term increase in CPP.

MAIN METHODS

Mice were treated with atropine or a non-selective CRF (corticotropin-releasing factor) receptor antagonist (alpha-helical CRF (9-41)), before being submitted to a 2-h stress session. Then, CPP and protease activity in colonic contents (total proteolytic, trypsin activity, and mouse mast cell protease (MMCP)-1 levels) were determined. The effects of colonic contents from sham-stressed or stressed animals on CPP were evaluated in mice colonic tissues mounted in Ussing chambers, in presence or not of soybean trypsin inhibitor (SBTI) or FSLLRY, a protease-activated receptor-2 (PAR2) antagonist.

KEY FINDINGS

Acute stress significantly increased CPP, proteolytic and trypsin activities, and MMCP-1 levels. Atropine inhibited stress-induced impairment of CPP and strongly diminished total proteolytic and trypsin activities in stressed animals, but not MMCP-1 levels. Colonic contents from stressed animals increased CPP in mice tissues, this effect being inhibited by SBTI and PAR2 antagonist.

SIGNIFICANCE

Acute stress activates cholinergic pathways, to trigger exocrine pancreatic secretion. Trypsin, released in these conditions, may be responsible for colonic barrier alterations through the activation of PAR2.

Intestinal microbiota during infancy and its implications for obesity

Obesity is a worldwide epidemic, threatening both industrialized and developing countries, and is accompanied by a dramatic increase in obesity-related disorders, including type 2 diabetes mellitus, hypertension, cardiovascular diseases, and nonalcoholic fatty liver disease. Recent studies have shown that the gut microbial community (microbiota) is an environmental factor that regulates obesity by increasing energy harvest from the diet and by regulating peripheral metabolism. However, there are no data on how obesogenic microbiotas are established and whether this process is determined during infancy. The sterile fetus is born into a microbial world and is immediately colonized by numerous species originating from the surrounding ecosystems, especially the maternal vaginal and fecal microflora. This initial microbiota develops into a complex ecosystem in a predictable fashion determined by internal (eg, oxygen depletion) and external (eg, mode of birth, impact of environment, diet, hospitalization, application of antibiotics) factors. We discuss how the gut microbiota regulates obesity and how environmental factors that affect the establishment of the gut microbiota during infancy may contribute to obesity later in life.

Recollection of childhood abdominal pain in adults with functional gastrointestinal disorders

OBJECTIVE

It is hypothesized that adults who can recall abdominal pain as children are at risk of experiencing a functional gastrointestinal disorder (FGID), but this is not specific to any particular FGID. The aim of this study was to evaluate the association between recollecting abdominal pain as a child and experiencing a FGID.

MATERIAL AND METHODS

A valid self-reported questionnaire of GI symptoms was mailed to a random population-based sample in Olmsted County, Minnesota. Logistic regression models adjusting for age, gender, body mass index (BMI), somatization, and other factors were used to estimate the odds ratios (ORs) for having a FGID in individuals recalling bouts of stomach or abdominal pain in childhood (before age 15).

RESULTS

Overall, 2298 (55%) of a total of 4194 eligible adult subjects returned a completed questionnaire. Of the respondents, 213 (9%) recalled experiencing abdominal pain as children. Adults who recalled experiencing abdominal pain in childhood had greater odds for reporting symptoms of a FGID (OR 1.9; 95% CI 1.4-2.7). Recalling abdominal pain in childhood was significantly associated with irritable bowel syndrome (IBS) (OR 2.5; 95% CI 1.7-3.6) but not gastroesophageal reflux, dyspepsia, constipation, or diarrhea, adjusting for age, gender, BMI, somatic symptoms, marital status, and education.

CONCLUSIONS

Recollection of childhood abdominal pain is specifically associated with IBS in adults. This suggests that a proportion of adults with IBS may have onset of symptoms of abdominal pain during childhood.

Genes and irritable bowel syndrome: is there a link?

Advances in genetics and genomics during the past decade, including sequencing of the human genome and DNA sequencing technologies, have made it possible to discover the genetic basis for many diseases. With the discovery of multiple genetic loci for gastrointestinal diseases such as Crohn's disease, some have begun to wonder-Could there be a genetic basis for irritable bowel syndrome (IBS)? This article summarizes the evidence for and against a link between genes and IBS. In addition, a gene-environment paradigm is presented to combine the two opposing hypotheses, as IBS may represent a complex genetic disorder that results from the interaction of several genes and environmental risk factors.

Factors influencing functional abdominal pain in children

Functional gastrointestinal disorders (FGIDs) commonly affect children and are associated with short- and long-term morbidity. Although the pathogenesis of pain-related FGIDs remains incompletely understood, most investigators agree on a multifactorial etiology and the presence of an altered brain-gut interaction. A continuous interplay of genetic and environmental factors appears to shape the development of the central and enteric nervous systems. The biopsychosocial model is the current operational framework for children with FGIDs, as it recognizes the interaction between social and environmental influences and psychological and physiologic processes. The biopsychosocial model proposes that specific permutations of genetic susceptibility, early life experiences, sociocultural issues, and coping mechanisms could explain the variability in clinical presentation and outcome among individuals.

Early life risk factors that contribute to irritable bowel syndrome in adults: a systematic review

BACKGROUND

Irritable bowel syndrome (IBS) is a common disorder that occurs in adults. The natural history of symptoms and risk factors that contribute to IBS may begin in childhood. The aim of this systematic review was to determine what early life factors contribute to the development of IBS in adolescents and adults.

METHODS

A computer-assisted search of the PubMed database from 1966 to 2007 was performed. The selection criteria were: (a) studies conducted in adolescents or adults with IBS that (b) investigate premorbid factors occurring specifically during the childhood period and are (c) associated with the outcomes of symptoms, quality of life, health-care utilization, and interferences with work or disability.

RESULTS

Twenty-five articles met inclusion criteria. The studies were categorized into articles examining the persistence of childhood gastrointestinal symptoms into adulthood, affluent childhood socioeconomic status and adult IBS, infantile and childhood trauma associated with the development of adult IBS, and social learning of illness behavior as predictors of adult IBS.

CONCLUSION

Pediatricians should be aware of potentially modifiable childhood risk factors and should consider interventions such as early symptom management of recurrent functional abdominal pain with cognitive therapies and parent education about social learning of illness behavior. Early treatment may have a long-term impact. Research examining the effect of affluent childhood socioeconomic status and early childhood trauma in the evolution of functional gastrointestinal disorders may help identify causative factors of IBS.

Corticotropin-releasing factor (CRF) in stress and disease: a review of literature and treatment perspectives with special emphasis on psychiatric disorders

The CRF family of neuropeptides and receptors is involved in a variety of stress responses, in the regulation of appetite, metabolic and inflammatory processes as well as intestinal movements. From a primarily psychiatric perspective, the present paper reviews the literature on its anatomy, physiology and its involvement in psychiatric, neurological and inflammatory diseases. Finally, recent developments in the pharmacological aspects of CRF in these diseases are reviewed.

New insights in the etiology and pathophysiology of irritable bowel syndrome: contribution of neonatal stress models

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, characterized by abdominal pain and disturbed defecation that cannot be explained by structural abnormalities. Although IBS symptoms (visceral pain, increased gut permeability, motility alterations) are clearly established, the etiology of this pathology is loosely understood. Nevertheless, clinical studies have reported that some early abuse (physical and psychological) is often associated with IBS development. Thus, loss and separation in the family during childhood may contribute to the IBS development. The recent development of animal models has pointed out the importance of early traumatic experiences in favoring the occurrence of IBS in adult life. Among these different models, neonatal maternal deprivation (NMD), neonatal colonic irritation (inflammatory stimuli), and neonatal colonic pain (rectal distension) have been described to mimic some cardinal features of IBS. The purpose of this review is 3-fold. First, to present the different neonatal stress models. Second, to review the literature on the influence of these early traumatic experiences on the gastrointestinal tract disturbances observed in adult life. Finally, we will also present the mediators and mechanisms involved in gut dysfunction triggered by NMD and probably in IBS.

Long-term colonic hypersensitivity in adult rats induced by neonatal unpredictable vs predictable shock

Our goal was to examine the relationship between early life trauma and the development of visceral hypersensitivity in later life in irritable bowel syndrome (IBS). Rat pups underwent neonatal conditioning: (i) paired odour-shock, where odour is a predictable shock signal, (ii) unpaired odour-shock, where odour is an unpredictable shock signal or (iii) control odour-only with odour presentations and handling without shock. At maturity, colorectal sensitivity was measured as a visceromotor behavioural response. In adulthood, colorectal distension (CRD) induced a pressure-dependent increase in the number of abdominal muscle contractions all three experimental groups. However, compared to animals that had received control odour-only presentations in infancy, there was an attenuated response to CRD in animals previously exposed to neonatal predictable shock pups and an exaggerated response in the animals previously exposed to neonatal unpredictable shock. Adult responses to CRD were altered by infant experience with shock trauma. However, depending on the context of that early life trauma, there are major differences between the long-term effects of that early life trauma on colonic sensitivity compared to controls. These results strengthen the link between early life trauma and adult IBS, and suggest that unpredictable trauma is a critical factor for later life disorders.

Social learning contributions to the etiology and treatment of functional abdominal pain and inflammatory bowel disease in children and adults

This paper reviews empirical work on cognitive and social learning contributions to the etiology and treatment of illness behavior associated with functional abdominal pain and inflammatory bowel disease. A particular emphasis is placed on randomized controlled trials, the majority of which are multi-modal in orientation, incorporating elements of cognitive behavioral therapy, social learning, and relaxation. Based on this review, we offer methodological and clinical suggestions: (1) Research investigations should include adequate sample sizes, long-term follow-up assessments, and a credible, active control group. (2) Standard gastrointestinal practice should include, when appropriate, learning opportunities for patients and family members, for example, instruction regarding the encouragement of wellness behavior.

Pathways involved in gut mucosal barrier dysfunction induced in adult rats by maternal deprivation: corticotrophin-releasing factor and nerve growth factor interplay

Neonatal maternal deprivation (NMD) increases gut paracellular permeability (GPP) through mast cells and nerve growth factor (NGF), and modifies corticotrophin-releasing factor (CRF) and corticosterone levels. CRF, corticosterone and mast cells are involved in stress-induced mucosal barrier impairment. Consequently, this study aimed to specify whether corticosteronaemia and colonic expression of both preproCRF and CRF are modified by NMD, and to determine if altered expression may participate in the elevated GPP in connection with NGF and mast cells. Male Wistar rat pups were either separated from postnatal days 2-14, or left undisturbed with their dam. At 12 weeks of age, adult rats were treated with mifepristone (an antagonist of corticoid receptors), alpha-helical CRF((9-41)) (a non-specific CRF receptor antagonist), or SSR-125543 (CRF-R(1) receptor antagonist). We also determined corticosteronaemia and both colonic preproCRF and CRF expression. Then, control rats were treated by CRF, doxantrazole (mast cell stabilizer), BRX-537A (a mast cell activator) and anti-NGF antibody. NMD did not modify colonic CRF level but increased colonic preproCRF expression and corticosteronaemia. Peripheral CRF, via CRF-R(1) receptor, but not corticosterone, was involved in the elevated GPP observed in these rats, through a mast-cell-mediated mechanism, since the increase of GPP induced by exogenous CRF was abolished by doxantrazole. Anti-NGF antibody treatment also reduced the elevated GPP induced by CRF or BRX-537A. CRF acts through CRF-R(1) receptors to stimulate NGF release from mast cells, which participates in the elevated GPP observed in NMD adult rats. This suggests that early traumatic experience induced neuro-endocrine dysfunction, involved in alterations of gut mucosal barrier.

In vivo and transgenic animal models used to study visceral hypersensitivity

Measurement of visceral sensitivity in animals is mainly based on 'pseudoaffective' responses, which are brain stem reflexes. For example, in female, but not male rats, acute partial restraint stress induces hypersensitivity to colorectal distension. Mucosal mast cell density increases in rats after nematode infection or maternal deprivation, and both also induce colon hypersensitivity. Significantly, the proximity between nerves and mast cells has been found to be increased in adult rats submitted to maternal deprivation. Protease activation of the proteinase-activated receptor-2 also increases visceral nociception in rats, suggesting that an increase in paracellular permeability may be the primum movens in several animal models of visceral hypersensitivity. Accumulating evidence suggests that sensitization of visceral afferents is not restricted to the presumed nociceptor population, suggesting that most of the mechanosensitive afferent population can contribute to visceral discomfort and pain. Other inflammation-produced changes (e.g. subunit composition of purine-gated P2X channels) in visceral sensory neurones may also contribute to visceral hypersensitivity. This article discusses use of in vivo strategies (and transgenic mouse models) to reveal putative roles in mechanosensitivity and sensitization for molecules not previously considered to have mechanosensory functions.

Neonatal immune challenge exacerbates experimental colitis in adult rats: potential role for TNF-alpha

Early life events and childhood infections have been associated with the development and onset of inflammatory bowel disease in adulthood. However, the consequences of neonatal infection in the development and severity of colitis are not established. We investigated the effects of a neonatal (postnatal day 14) or juvenile (postnatal day 28) immune challenge with LPS on 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced damage and weight loss, as well as on food intake and body temperature in adult rats. Neonatally (n)LPS-treated rats developed more severe colitis than control animals, reflected in a greater loss of weight and a significantly increased macroscopic tissue damage score. These findings were associated with a hypothermic response after TNBS treatment in nLPS rats, but not in neonatally saline-treated rats receiving TNBS. These differences were not seen after TNBS in rats that had received LPS on postnatal day 28. Plasma corticosterone was measured as an index of adult hypothalamic-pituitary-adrenal (HPA) axis activation as was TNF-alpha, a proinflammatory cytokine associated with inflammatory bowel disease. Four days after TNBS treatment, plasma corticosterone was unaltered in all groups; however, TNF-alpha was significantly increased in adult TNBS-treated rats that had LPS as neonates compared with all other groups. In conclusion, neonatal, but not later, exposure to LPS produces long-term exacerbations in the development of colitis in adults. This change is independent of HPA axis activation 4 days after TNBS treatment but is associated with increased circulating TNF-alpha, suggestive of an exaggerated immune response in adults exposed to neonatal infection.

Adolescent–Parent Relationships in the Context of Adolescent Chronic Pain Conditions

OBJECTIVE

This study explored adolescent-parent relationships in families of adolescents with chronic pain.

METHODS

A retrospective review was conducted on 112 adolescents with chronic pain who presented for clinical evaluation at an outpatient pediatric multidisciplinary pain management clinic. Adolescents reported on pain severity and duration, functional disability, and psychological distress. Parents responded to a measure of adolescent-parent relationship distress.

RESULTS

The findings show that as a group, parents of adolescents with chronic pain syndromes reported less adolescent-parent relationship distress compared to normative data. Adolescent-parent relationship distress was inversely correlated with pain severity. A multiple regression model containing indicators of global psychological distress, pain severity, and adolescent-parent relationship distress predicted levels of adolescents' functional disability. Pain severity and functional disability were more closely linked at the low end of Adolescent-Parent Relationship Domain scores.

DISCUSSION

The findings suggest important directions for future research to advance our understanding of the role of adolescent-parent relationships in the pain-disability cycle.

From the bench to the 'crib'-side: implications of scientific advances to paediatric neurogastroenterology and motility

Paediatric gastrointestinal motility disorders may present in the neonatal period as the result of a congenital insult that occurred during embryonic development or as a manifestation of an abnormal genetic background. Functional gastrointestinal and motility disorders may also be acquired and present during childhood as the first presentation of a condition that can persist or re-occur throughout adolescence and adulthood. These disorders can have a significant psychological and financial impact on the lives of the affected children and their families. Recently, enteric neuroscience research has advanced the understanding of the pathogenesis and treatment of uncommon congenital or developmental gastrointestinal motility disorders such as Hirschsprung disease and chronic intestinal pseudo-obstruction. In addition, research has contributed to improvements in the understanding of more prevalent functional gastrointestinal disorders in children, such as chronic constipation and functional abdominal pain syndromes. The purpose of this review is to highlight these advances with particular regard to the clinical impact they have in the understanding and management of disorders in the field of paediatric neurogastroenterology and motility.

Neonatal maternal separation causes colonic dysfunction in rat pups including impaired host resistance

Previous studies have shown that early life stress in the form of intermittent maternal separation (MS) predisposes adult rats to develop stress-induced intestinal mucosal dysfunction and visceral hypersensitivity. However, the mechanism involved in the functional abnormalities is unclear. Our aim was to study immature animals during or shortly after exposure to MS to determine whether there are early pathophysiological changes in the gut. Sprague-Dawley rat pups were individually separated from the dam for 3 h/d from 4 to 21 d of age; nonseparated (NS) control pups remained in the home cage with the dam. On d 19-20, d 24-25, and d 29-30, blood was collected for corticosterone measurement, and colonic tissues were removed for functional and morphologic assessment. Corticosteroid levels were elevated in MS pups compared with NS, indicating that MS was indeed stressful. The distal colon demonstrated significantly enhanced ion secretion and macromolecular permeability at d 19-20 and d 24-25, returning to normal by d 29-30. Electron microscopy and bacterial culture studies indicated bacteria adhering to and penetrating into the colonic epithelium of the MS pups at all time points, while such events were rare in NS pups. The pathophysiological changes were inhibited by injecting pups sc with a corticotropin-releasing hormone (CRH) receptor antagonist daily during MS. Our studies indicate that early psychological trauma predisposes neonatal rats to develop persistent mucosal barrier dysfunction, including impaired host defense to luminal bacteria, by a mechanism involving peripheral CRH receptors.

Corticotropin-releasing factor receptor 1 mediates acute and delayed stress-induced visceral hyperalgesia in maternally separated Long-Evans rats

In rodents, maternal pup interactions play an important role in programming the stress responsiveness of the adult organism. The aims of this study were 1) to determine the effect of different neonatal rearing conditions on acute and delayed stress-induced visceral sensitivity as well as on other measures of stress sensitivity of the adult animal; and 2) to determine the role of corticotropin-releasing factor receptor (CRF-R) subtype 1 (CRF(1)R) in mediating visceral hypersensitivity. Three groups of male Long-Evans rat pups were used: separation from their dam for 180 min daily from postnatal days 2-14 (MS180), daily separation (handling) for 15 min (H), or no handling. The visceromotor responses (VMR) to colorectal distension, stress-induced colonic motility, and anxiety-like behavior were assessed in the adult rats. The VMR was assessed at baseline, immediately after a 1-h water avoidance (WA) stress, and 24 h poststress. Astressin B, a nonselective CRF-R antagonist, or CP-154,526, a selective CRF(1)R antagonist, was administered before the stressor and/or before the 24-h measurement. MS rats developed acute and delayed stress-induced visceral hyperalgesia. In contrast, H rats showed hypoalgesia immediately after WA and no change in VMR on day 2. MS rats with visceral hyperalgesia also exhibited enhanced stress-induced colonic motility and increased anxiety-like behavior. In MS rats, both CRF-R antagonists abolished acute and delayed increases in VMR. Rearing conditions have a significant effect on adult stress responsiveness including immediate and delayed visceral pain responses to an acute stressor. Both acute and delayed stress-induced visceral hypersensitivity in MS rats are mediated by the CRF/CRF(1)R system.

The epidemiology of childhood recurrent abdominal pain in Western countries: a systematic review

OBJECTIVE

Recurrent abdominal pain (RAP) of childhood is a common problem encountered by clinicians. The aim of this study was to systematically review published literature about the prevalence, incidence, natural history, and co-morbid conditions of childhood RAP in western countries.

METHODS

A computer-assisted search of MEDLINE, EMBASE, and Current Contents/Science Edition databases was performed. Study selection criteria included: (1) United States and European population and school-based samples of children; (2) diagnostic criteria of RAP; and (3) published in full manuscript form in English. Data were extracted, tabulated, and presented in descriptive form.

RESULT

The prevalence of RAP ranged from 0.3 to 19% (median 8.4; IQR 2.3-14.7). Published studies in children demonstrate a higher prevalence of RAP in females, with the highest prevalence of symptoms between 4 and 6 yr and early adolescence. Identified studies demonstrated associations between RAP and the child's familial and socioeconomic environment. In addition, childhood RAP was reported to be associated with psychological co-morbidity in childhood and adulthood. Population/school-based studies have not, however, established the incidence of this disorder, what features predict long-standing symptoms, or whether RAP is a risk factor for adult functional bowel disorders.

CONCLUSION

RAP is a common complaint of childhood with associated familial, psychological, and co-morbid conditions. Epidemiologic studies of RAP in children may offer information on the evolution of functional bowel disorders through the lifespan.

Decreased cortisol awakening response after early loss experience

Early loss experience (ELE) due to death or separation is a major risk factor for the development of several psychiatric and physical disorders in adulthood. Few studies have focused on the effects of ELE on neuroendocrine systems, which might mediate this risk in part. The goal of this study was to evaluate salivary cortisol responses to awakening in individuals with and without ELE. A total of 95 healthy college students (29 men, 66 women) completed a questionnaire on ELE and were instructed to collect saliva immediately after awakening and 30 min later. Fifty-five of the 95 subjects reported having experienced the separation or divorce of their parents and/or the death of a close relative before the age of 14 years. Subjects with such ELE exhibited decreased salivary cortisol responses to awakening compared to subjects without ELE (net increase: 4.78 nmol/l versus 9.83 nmol/l; t93 = 2.88, p = 0.005). The effect was most pronounced in individuals who experienced multiple types of ELE, while there were no sex differences. In conclusion, ELE appears to be associated with decreased salivary cortisol responses to awakening. Low cortisol awakening responses are believed to reflect altered dynamics of the hypothalamic-pituitary-adrenal (HPA) axis, possibly conferring risk for certain stress-related disorders.