Anticipation of public speaking and sleep and the hypothalamic-pituitary-adrenal axis in women with irritable bowel syndrome

Genetic Variants in Carbohydrate Digestive Enzyme and Transport Genes Associated with Risk of Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is characterized by abdominal pain and alterations in bowel pattern, such as constipation (IBS-C), diarrhea (IBS-D), or mixed (IBS-M). Since malabsorption of ingested carbohydrates (CHO) can cause abdominal symptoms that closely mimic those of IBS, identifying genetic mutations in CHO digestive enzymes associated with IBS symptoms is critical to ascertain IBS pathophysiology. Through candidate gene association studies, we identify several common variants in TREH, SI, SLC5A1 and SLC2A5 that are associated with IBS symptoms. By investigating rare recessive Mendelian or oligogenic inheritance patterns, we identify case-exclusive rare deleterious variation in known disease genes (SI, LCT, ALDOB, and SLC5A1) as well as candidate disease genes (MGAM and SLC5A2), providing potential evidence of monogenic or oligogenic inheritance in a subset of IBS cases. Finally, our data highlight that moderate to severe IBS-associated gastrointestinal symptoms are often observed in IBS cases carrying one or more of deleterious rare variants.

Genetic Variations in TrkB.T1 Isoform and Their Association with Somatic and Psychological Symptoms in Individuals with IBS

Irritable bowel syndrome (IBS), a disorder of gut-brain interaction, is often comorbid with somatic pain and psychological disorders. Dysregulated signaling of brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin-related kinase B (TrkB), has been implicated in somatic-psychological symptoms in individuals with IBS. Thus, we investigated the association of 10 single nucleotide polymorphisms (SNPs) in the regulatory 3' untranslated region (UTR) of NTRK2 (TrkB) kinase domain-deficient truncated isoform (TrkB.T1) and the BDNF Val66Met SNP with somatic and psychological symptoms and quality of life in a U.S. cohort (IBS n=464; healthy controls n=156). We found that the homozygous recessive genotype (G/G) of rs2013566 in individuals with IBS is associated with worsened somatic symptoms, including headache, back pain, joint pain, muscle pain, and somatization as well as diminished sleep quality, energy level and overall quality of life. Validation using U.K. BioBank (UKBB) data confirmed the association of rs2013566 with increased likelihood of headache. Several SNPs (rs1627784, rs1624327, rs1147198) showed significant associations with muscle pain in our U.S. cohort. Notably, these SNPs are predominantly located in H3K4Me1-enriched regions, suggesting their enhancer and/or transcription regulation potential. Together, our findings suggest that genetic variation within the 3'UTR region of the TrkB.T1 isoform may contribute to comorbid conditions in individuals with IBS, resulting in a spectrum of somatic and psychological symptoms that may influence their quality of life. These findings advance our understanding of the genetic interaction between BDNF/TrkB pathways and somatic-psychological symptoms in IBS, highlighting the importance of further exploring this interaction for potential clinical applications.

Emotional stress responsivity of patients with IBS - a systematic review

OBJECTIVE

Irritable bowel syndrome (IBS) is a highly prevalent disorder of the gut-brain interaction characterized by abdominal discomfort and pain associated with altered bowel habits in the absence of structural abnormalities. Chronic psychological stress is considered a risk factor for the development of IBS. The multifactorial pathogenesis involves complex interactions between biological, psychological and social factors, yet the underlying mechanisms have not been fully understood.

METHODS

We systematically reviewed the literature from the databases MEDLINE, Embase and PsycINFO to assess stress responsivity of patients with IBS in comparison to healthy individuals, specifically focusing acute psychological stressors.

RESULTS

A total of 37 case-control studies were included in the narrative synthesis. Findings comprised subjective changes in emotion (k = 18) and of gastrointestinal symptoms (k = 8) as well as objective parameters of gastrointestinal motility (k = 10), autonomic nervous system (k = 23), hypothalamic-pituitary-adrenal axis (k = 11), functional brain activity (k = 7) and immune system (k = 3). Mental stress was found to increase IBS-specific symptomatology and alter gastrointestinal motility. Some patients with IBS showed stress-induced emotional hyperresponsivity and different patterns of neural activation. Autonomic and endocrine stress responses depend on the type of stressor and showed no clear evidence of differential reactivity, partly due to confounding factors. Data on acute immunological changes remains sparse and requires further investigation.

CONCLUSIONS

Current evidence suggests altered stress reactivity in patients with IBS however, it remains unclear whether it can be attributed to the syndrome itself or the high prevalence of psychiatric comorbidities.

Concordant pattern of the HPA axis response to visceral stimulation and CRH administration

The physiological and psychological mechanisms explaining the individual variability in the stress response are poorly understood. We tested the hypothesis that hypothalamic-pituitary- adrenal (HPA) axis responses to colorectal stimulation affect HPA axis reactivity to corticotropin-releasing hormone (CRH), the visceral pain threshold, and perceived stress. We examined 31 healthy volunteers and 27 individuals with irritable bowel syndrome. According to the ACTH response to colorectal stimulation, the participants were classified into three groups: flattened, decreased, and increased. We found significant differences in the abdominal pain threshold, discomfort threshold, and sensitivity to anxiety among the groups. There were significant differences in the ACTH change and peak level after CRH administration among the groups. The area under the curve of the cortisol response to CRH was significantly different among the groups. The increased group showed a higher basal ACTH level, earlier peak level in the CRH administration test, and higher stress rating during the experiment. The increased group had an exaggerated psychological and physiological stress response, whereas the decreased group had a higher anticipatory endocrine response, stress, and sensitivity to anxiety. Further studies are needed to determine factors including gut microbiota on the individual difference in HPA response.

Associations between chronotype, social jetlag, and weekday sleep in women with irritable bowel syndrome

Sleep deficiency is well-documented in individuals with irritable bowel syndrome (IBS). Sleep deficiency includes poor sleep quality and an inadequate amount of sleep, and is a modifiable risk factor for IBS symptom exacerbations. Prior studies in other populations have identified chronotype and social jetlag (SJL) as important determinants of sleep outcomes. However, chronotype and SJL have not been examined in women with IBS. We used multiple linear regression analyses to determine whether chronotype and SJL are associated with sleep outcomes during weekdays among women with IBS predominant constipation (IBS-C), IBS with predominant diarrhea (IBS-D), and healthy control (HC) women. This sample included 62 women with IBS (IBS-C = 29, IBS-D = 33) and 58 HC women who completed a 28-day daily diary from two study cohorts. The average age of the participants was 30.1 (SD 7.2) years. Chronotype was estimated from daily diary data with the average mid-sleep time on weekends (MSW^we). SJL was calculated by subtracting the average mid-sleep time on weekdays from MSW^we. Sleep outcomes included diary assessments of sleep quality, sleep need met, and restorative sleep during weekdays. In HCs, later chronotype was predictive of lower sleep quality (β = -0.19, p < .01), a perception of sleep need not met (β = -0.17, p < .001), and a less restorative sleep during weekdays (β = -0.15, p = .073), whereas SJL was not associated with sleep outcomes. Similar to HCs, earlier chronotypes in women with IBS-C reported better sleep quality and more sufficient sleep need met and restorative sleep during weekdays than later chronotypes (all p > .05). Compared to HCs, the relationships of chronotype with weekday sleep outcomes in the women with IBS-D were in the opposite directions (all p < .05). This exploratory study suggests that chronotype expression may reflect the temporal associations of sleep outcomes within IBS bowel pattern predominance subgroups, particularly sleep quality and sleep need met. Additional investigations are warranted to examine whether specific temporal attributes of symptoms and/or symptom severity associated with IBS subgroups contribute to chronotype expression.

Psychological, physical, and sleep comorbidities and functional impairment in irritable bowel syndrome: Results from a national survey of U.S. adults

BACKGROUND/AIMS

Patients with irritable bowel syndrome (IBS) in referral practice commonly report mental disorders and functional impairment. Our aim was to determine the prevalence of mental, physical and sleep-related comorbidities in a nationally representative sample of IBS patients and their impact on functional impairment.

METHODS

IBS was defined by modified Rome Criteria based on responses to the chronic conditions section of the National Comorbidity Survey-Replication. Associations between IBS and mental, physical and sleep disorders and 30-day functional impairment were examined using logistic regression models.

RESULTS

Of 5,650 eligible responders, 186 met criteria for IBS {weighted prevalence 2.5% (SE = 0.3)}. Age >60 years was associated with decreased odds (OR = 0.3; 95% CI:.1-.6); low family income (OR = 2.4; 95% CI:1.2-4.9) and unemployed status (OR = 2.3; 95% CI:1.2-4.2) were associated with increased odds of IBS. IBS was significantly associated with anxiety, behavior, mood disorders (ORs 1.8-2.4), but not eating or substance use disorders. Among physical conditions, IBS was associated with increased odds of headache, chronic pain, diabetes mellitus and both insomnia and hypersomnolence related symptoms (ORs 1.9-4.0). While the association between IBS and patients' role impairment persisted after adjusting for mental disorders (OR = 2.4, 95% CI 1.5-3.7), associations with impairment in self-care, cognition, and social interaction in unadjusted models (ORs 2.5-4.2) were no longer significant after adjustment for mental disorders.

CONCLUSION

IBS is associated with socioeconomic disadvantage, comorbidity with mood, anxiety and sleep disorders, and role impairment. Other aspects of functional impairment appear to be moderated by presence of comorbid mental disorders.

Tryptophan Metabolites in Irritable Bowel Syndrome: An Overnight Time-course Study

Background/Aims

Patients with irritable bowel syndrome (IBS) often report poor sleep quality. Whether poor sleep is associated with tryptophan (Trp) metabolites is unknown. We compared serum Trp metabolites in women with IBS and healthy controls (HCs) using targeted liquid chromatography mass spectrometry (LC-MS)-based profiling. In IBS only, we explored whether Trp metabolites are associated with IBS symptoms and subjective and objective sleep indices, serum cortisol, plasma adrenocorticotropic hormone (ACTH), and cortisol/ACTH levels.

Methods

Blood samples were obtained every 80 minutes in 21 HCs and 38 IBS subjects following an anticipation-of-public-speaking stressor during a sleep laboratory protocol. Subjects completed symptom diaries for 28 days. Adjacent values of metabolites were averaged to represent 4 time-periods: awake, early sleep, mid-sleep, and mid-to-late sleep. Thirteen of 20 targeted Trp metabolites were identified.

Results

Ten of 13 Trp metabolites decreased across the night, while nicotinamide increased in both groups. A MANOVA omnibus test performed after principal component analysis showed a significant difference in these 13 principal component (P = 0.014) between groups. Compared to HCs, nicotinamide levels were higher and indole-3-lactic acid levels lower in the IBS group. Melatonin and indole-3-acetic acid levels were associated with several subjective/objective sleep measures; decreased stool consistency/frequency and abdominal pain were positively associated with melatonin and serotonin in the IBS group. The kynurenine and kynurenic acid were associated with ACTH (positively) and cortisol/ACTH (negatively).

Conclusions

Nighttime Trp metabolites may provide clues to poor sleep and stress with IBS. Further study of the mechanism of metabolite action is warranted.

Sleep quality and functional gastrointestinal disorders. A psychological issue

OBJECTIVE

Sleep disorders are often associated with functional gastrointestinal disorders (FGIDs). This study aims to evaluate the association of sleep disorders with specific FGIDs and to assess the related importance of psychological disorders.

METHODS

We included 1009 consecutive patients with FGIDs (70.9% females). The patients completed a Rome III questionnaire and after a psychological evaluation on anxiety and depression they were classified according to their sleep disorders using a 7-point grading scale: Groups 1-3, drowsiness (severe, moderate, mild); Group 4, no change; Groups 5-7, insomnia (mild, moderate, severe). Multinomial logistic regression using sleep group as a dependent variable with no sleep change as reference and body mass index, FGIDs, anxiety and depression as independent variables were used for statistical analysis.

RESULTS

Altogether 667 (66.1%) patients reported changes in sleep disorders, of whom 487 (48.3%) had decreased sleep and 180 (17.8%) had increased sleep while 342 (33.9%) reported no change. Depression was lower in patients with no change in sleep pattern and increased with the severity of their sleep disorder (P < 0.001). State-anxiety is associated with moderate drowsiness (P = 0.024), while trait anxiety is associated with mild insomnia (P = 0.048). FGIDs associated with sleep disorders included chest pain, epigastric pain syndrome, irritable bowel syndrome with constipation, diarrhea, bloating, fecal incontinence and proctalgia fugax.

CONCLUSION

Sleep disorders are associated with FGIDs, especially in the presence of depressive symptoms.

Sleep disturbances in irritable bowel syndrome: a systematic review

BACKGROUND

Sleep disturbances are well-documented among persons with irritable bowel syndrome (IBS). Difficulty in falling asleep, shorter sleep time, frequent arousal and awakenings, or non-restorative sleep are the most common manifestations. Sleep disturbances are also related to a higher risk of having IBS. Some researchers have provided evidence of a positive association between poorer subjective sleep quality and increased severity and frequency in gastrointestinal (GI) symptoms in those with IBS. However, findings from studies using objective sleep and activity measures, such as polysomnography and actigraphy, are inconclusive.

PURPOSE

This systematic review of the literature between 1990 and 2015 evaluates the evidence of sleep disturbances in adults with IBS and their relationship with GI symptoms.

Rare Variants of the Serotonin Transporter Are Associated With Psychiatric Comorbidity in Irritable Bowel Syndrome

Alterations in serotonin signaling are suspected in the pathophysiology of irritable bowel syndrome (IBS). By modulating the extracellular reuptake of serotonin, the serotonin transporter (SERT) acts as a key regulator of the bioavailability of serotonin. This study is the first to investigate the impact of rare SERT variants (i.e., those with a minor allele frequency of < 1%) on the risk for IBS, gastrointestinal (GI) symptom level, response to cognitive-behavioral treatment, and psychiatric comorbidity. We sequenced a 0.19 megabase chromosomal stretch containing the SERT gene and surrounding regions in a community sample of 304 IBS patients and 83 controls. We found no significant associations between rare variants in and around the SERT gene and IBS risk, GI symptom profile, or response to treatment. We found preliminary evidence, however, that IBS subjects with a history of either depression or anxiety were significantly more likely to carry multiple rare likely functional variant alleles than IBS patients without psychiatric comorbidity.

Biopsychosocial Aspects of Functional Gastrointestinal Disorders

In this paper, we provide a general framework for understanding the functional gastrointestinal disorders (FGID) from a biopsychosocial perspective. More specifically, we provide an overview of the recent research on how the complex interactions of environmental, psychological, and biological factors contribute to the development and maintenance of the FGID. We emphasize that considering and addressing all these factors is a conditio sine qua non for appropriate treatment of these conditions. First, we provide an overview of what is currently known about how each of these factors - the environment, including the influence of those in an individual's family, the individual's own psychological states and traits, and the individual's (neuro)physiological make-up - interact to ultimately result in the generation of FGID symptoms. Second, we provide an overview of commonly used assessment tools which can assist clinicians in obtaining a more comprehensive assessment of these factors in their patients. Finally, the broader perspective outlined earlier is applied to provide an overview of centrally acting treatment strategies, both psychological and pharmacological, which have been shown to be efficacious to treat FGID.

Balance of Autonomic Nervous System Predicts Who Benefits from a Self-management Intervention Program for Irritable Bowel Syndrome

Background/Aims

To determine if potential biomarkers can be used to identify subgroups of people with irritable bowel syndrome (IBS) who will benefit the most or the least from a comprehensive self-management (CSM) intervention.

Methods

In a two-armed randomized controlled trial a CSM (n = 46) was compared to a usual care (n = 46) group with follow-up at 3 and 6 months post randomization. Biomarkers obtained at baseline included heart rate variability, salivary cortisol, interleukin-10 produced by unstimulated peripheral blood mononuclear cells, and lactulose/mannitol ratio. Linear mixed models were used to test whether these biomarkers predicted improvements in the primary outcomes including daily abdominal pain, Gastrointestinal Symptom score and IBS-specific quality of life.

Results

The nurse-delivered 8-session CSM intervention is more effective than usual care in reducing abdominal pain, reducing Gastrointestinal Symptom score, and enhancing quality of life. Participants with lower nighttime high frequency heart rate variability (vagal modulation) and increased low frequency/high frequency ratio (sympathovagal balance) had less benefit from CSM on abdominal pain. Salivary cortisol, IL-10, and lactulose/mannitol ratio were not statistically significant in predicting CSM benefit. Baseline symptom severity interacts with treatment, namely the benefit of CSM is greater in those with higher baseline symptoms.

Conclusions

Cognitively-focused therapies may be less effective in reducing abdominal pain in IBS patients with higher sympathetic tone. Whether this a centrally-mediated patient characteristic or related to heightened arousal remains to be determined.

Early-life adversity and brain development: Is the microbiome a missing piece of the puzzle?

The prenatal and postnatal early-life periods are both dynamic and vulnerable windows for brain development. During these important neurodevelopmental phases, essential processes and structures are established. Exposure to adverse events that interfere with this critical sequence of events confers a high risk for the subsequent emergence of mental illness later in life. It is increasingly accepted that the gastrointestinal microbiota contributes substantially to shaping the development of the central nervous system. Conversely, several studies have shown that early-life events can also impact on this gut community. Due to the bidirectional communication between the gut and the brain, it is possible that aberrant situations affecting either organ in early life can impact on the other. Studies have now shown that deviations from the gold standard trajectory of gut microbiota establishment and development in early life can lead not only to disorders of the gastrointestinal tract but also complex metabolic and immune disorders. These are being extended to disorders of the central nervous system and understanding how the gut microbiome shapes brain and behavior during early life is an important new frontier in neuroscience.

Serum Tryptophan Metabolite Levels During Sleep in Patients With and Without Irritable Bowel Syndrome (IBS)

Poor sleep and stress are more frequently reported by women with irritable bowel syndrome (IBS) than by healthy control (HC) women. The pathophysiology linking poor sleep and stress to gastrointestinal symptoms remains poorly understood. We used a metabolomic approach to determine whether tryptophan (TRP) metabolites differ between women with and without IBS and whether the levels are associated with sleep indices and serum cortisol levels. This study sample included 38 women with IBS and 21 HCs. The women were studied in a sleep laboratory for three consecutive nights. On the third night of the study, a social stressor was introduced, then blood samples were drawn every 20 min and sleep indices were measured. Metabolites were determined by targeted liquid chromatography tandem mass spectrometry in a sample collected 1 hr after the onset of sleep. The ratios of each metabolite to TRP were used for analyses. Correlations were controlled for age and oral contraceptive use. Melatonin/TRP levels were lower (p = .005) in the IBS-diarrhea group versus the IBS-constipation and HC groups, and kynurenine/TRP ratios tended to be lower (p = .067) in the total IBS and IBS-diarrhea groups compared to HCs. Associations within the HC group included melatonin/TRP with polysomnography-sleep efficiency (r = .61, p = .006) and weaker positive correlations with the other ratios for either sleep efficiency or percentage time in rapid eye movement sleep (r > .40, p = .025-.091). This study suggests that reductions in early nighttime melatonin/TRP levels may be related to altered sleep quality in IBS, particularly those with diarrhea.

A sustained hypothalamic-pituitary-adrenal axis response to acute psychosocial stress in irritable bowel syndrome

BACKGROUND

Despite stress being considered a key factor in the pathophysiology of the functional gastrointestinal (GI) disorder irritable bowel syndrome (IBS), there is a paucity of information regarding the ability of IBS patients to respond to acute experimental stress. Insights into the stress response in IBS could open the way to novel therapeutic interventions. To this end, we assessed the response of a range of physiological and psychological parameters to the Trier Social Stress Test (TSST) in IBS.

METHOD

Thirteen female patients with IBS and 15 healthy female age-matched control participants underwent a single exposure to the TSST. Salivary cortisol, salivary C-reactive protein (CRP), skin conductance level (SCL), GI symptoms, mood and self-reported stress were measured pre- and post-exposure to the TSST.

RESULTS

The hypothalamic-pituitary-adrenal (HPA) axis response to the TSST was sustained in IBS, as shown by a greater total cortisol output throughout (p = 0.035) and higher cortisol levels measured by an area under the curve with respect to ground (AUCG) analysis (p = 0.044). In IBS patients, GI symptoms increased significantly during the recovery period following exposure to the TSST (p = 0.045). Salivary CRP and SCL activity showed significant changes in relation to stress but with no differential effect between experimental groups.

CONCLUSIONS

Patients with IBS exhibit sustained HPA axis activity, and an increase in problematic GI symptoms in response to acute experimental psychosocial stress. These data pave the way for future interventional studies aimed at identifying novel therapeutic approaches to modulate the HPA axis and GI symptom response to acute psychosocial stress in IBS.

Sleep measures predict next-day symptoms in women with irritable bowel syndrome

STUDY OBJECTIVES

Patients with irritable bowel syndrome (IBS) often report sleep disturbances. Previously, we have shown that self-reported sleep difficulties predicted exacerbations of next-day IBS symptoms, mood disturbance, and fatigue. The purpose of this study was to explore whether objectively measured sleep using actigraphy, as well as self-report, predicts next-day symptoms in women with IBS and to explore whether or not symptoms also predict self-report and objective sleep.

METHODS

Women aged 18-45 years with IBS were community-recruited (n = 24, mean age = 32 ± 8 years). Participants completed sleep and IBS symptom diaries for one menstrual cycle and wore Actiwatch-64 actigraphs for 7 days at home. Statistical analyses used generalized estimating equation (GEE) models.

RESULTS

Poorer self-reported sleep quality significantly (p < 0.05) predicted higher next-day abdominal pain, anxiety, and fatigue, but was not significant for gastrointestinal (GI) symptoms or depressed mood. Actigraphic sleep efficiency (SEF) significantly predicted worsening next-day anxiety and fatigue, but not abdominal pain, GI symptoms, or depressed mood. On temporally reversed analyses, none of the symptoms significantly predicted subsequent sleep, except that GI symptoms significantly predicted higher actigraphic sleep efficiency.

CONCLUSION

This small exploratory study supports previous findings that self-reported sleep disturbance predicted exacerbation of next-day symptoms in women with IBS and extends this relationship using an objective sleep measure. The study adds further evidence that sleep quality predicts subsequent IBS symptoms, but not the converse. The findings from this small study support the importance of additional longitudinal research to further understand the relationships between sleep and IBS.

Update on irritable bowel syndrome program of research

PURPOSE

This article provides an update and overview of a nursing research program focused on understanding the pathophysiology and management of irritable bowel syndrome (IBS).

METHODS

This review includes English language papers from the United States, Europe, and Asia (e.g., South Korea) from 1999 to 2013. We addressed IBS as a health problem, emerging etiologies, diagnostic and treatment approaches and the importance of a biopsychosocial model.

RESULTS

IBS is a chronic, functional gastrointestinal disorder characterized by recurrent episodes of abdominal pain and alterations in bowel habit (diarrhea, constipation, mixed). It is a condition for which adults, particularly women ages 20-45, seek health care services in both the United States and South Korea. Clinically, nurses play key roles in symptom prevention and management including designing and implementing approaches to enhance the patients' self-management strategies. Multiple mechanisms are believed to participate in the development and maintenance of IBS symptoms including autonomic nervous system dysregulation, intestinal inflammation, intestinal dysbiosis, dietary intolerances, alterations in emotion regulation, heightened visceral pain sensitivity, hypothalamic-pituitary-adrenal dysregulation, and dysmotility. Because IBS tends to occur in families, genetic factors may also contribute to the pathophysiology. Patients with IBS often report a number of co-morbid disorders and/or symptoms including poor sleep.

CONCLUSION

The key to planning effective management strategies is to understand the heterogeneity of this disorder. Interventions for IBS include non-pharmacological strategies such as cognitive behavior therapy, relaxation strategies, and exclusion diets.

Physiological underpinnings of irritable bowel syndrome: neurohormonal mechanisms

The gastrointestinal tract is a vast neuroendocrine organ with extensive extrinsic and intrinsic neural circuits that interact to control its function. Circulating and paracrine hormones (amine and peptide) provide further control of secretory, absorptive, barrier, motor and sensory mechanisms that are essential to the digestion and assimilation of nutrients, and the transport and excretion of waste products. Specialized elements of the mucosa (including enteroendocrine cells, enterocytes and immune cells) and the microbiome interact with other intraluminal contents derived from the diet, and with endogenous chemicals that alter the gut's functions. The totality of these control mechanisms is often summarized as the brain-gut axis. In irritable bowel syndrome (IBS), which is the most common gastrointestinal disorder, there may be disturbances at one or more of these diverse control mechanisms. Patients present with abdominal pain in association with altered bowel function. This review documents advances in understanding the pathophysiological mechanisms in the brain-gut axis in patients with IBS. It is anticipated that identification of one or more disordered functions in clinical practice will usher in a renaissance in the management of IBS, leading to effective therapy tailored to the needs of the individual patient.

Conditioned pain modulation in women with irritable bowel syndrome

Evidence suggests that patients with irritable bowel syndrome (IBS) are more vigilant to pain-associated stimuli. The aims of this study were to compare women with IBS (n = 20) to healthy control (HC, n = 20) women on pain sensitivity, conditioned pain modulation (CPM) efficiency, and salivary cortisol levels before and after the CPM test and to examine the relationship of CPM efficiency with gastrointestinal pain, somatic pain, psychological distress symptoms, and salivary cortisol levels in each group. Women, aged 20-42 years, gave consent, completed questionnaires, and kept a symptom diary for 2 weeks. CPM efficiency was tested with a heat test stimulus and cold water condition stimulus in a laboratory between 8 and 10 a.m. on a follicular phase day. Salivary cortisol samples were collected just before and after the experimental testing. Compared to the HC group, women with IBS reported more days with gastrointestinal and somatic pain/discomfort, psychological distress, fatigue, and feeling stressed. During the CPM baseline testing, women with IBS reported greater pain sensitivity compared to the HC group. There was no significant group difference in salivary cortisol levels nor in CPM efficiency, though a post-hoc analysis showed a higher prevalence of impaired CPM efficiency among IBS subjects with more severe lower-GI symptoms. In the IBS group, reduced CPM efficiency was associated with daily abdominal pain/discomfort and psychological distress. Overall, women with IBS exhibited an increased sensitivity to thermal stimuli. Impaired CPM was present in a subset of women with IBS.