Stress and brain functional changes in patients with Crohn's disease: A functional magnetic resonance imaging study

A Heavy Feeling in the Stomach: Neural Correlates of Anxiety in Crohn's Disease

INTRODUCTION

Crohn's disease (CD) is a chronic inflammatory condition associated with psychological stress and anxiety. Functional magnetic resonance imaging (fMRI) studies have shown differences in brain function between patients with CD and healthy controls (HC). This study aimed to compare the neural correlates of anxiety inindividuals with CD relative to HC, using resting-state fMRI data.

METHODS

Participants filled in the State-Trait Anxiety Inventory (STAI), a validated tool for measuring anxiety, and underwent an MRI acquisition, including both structural and functional sequences, to identify brain regions associated with anxiety scores.

RESULTS

Seventeen patients with CD and eighteen HC matched for age, education, and sex participated in the study. No significant group differences emerged in the STAI scores. However, resting-state fMRI analysis revealed distinct patterns of functional connectivity associated with anxiety scores for the two study groups. Among CD group, greater STAI scores correlated with increased functional connectivity, whereas, in HC, they correlated with decreased functional connectivity. Significant clusters were found in brain regions belonging to specific resting-state networks (RSNs): (a) Posterior Cingulate Cortex (PCC, within the Default Mode Network), (b) left Middle Frontal Gyrus (within the Left Fronto-Parietal Network), and (c) PCC and right Superior Temporal Gyrus (within the Dorsal Attention Network).

CONCLUSION

The differential association between functional connectivity and STAI scores observed for CD and HC participants was located in areas within self-referential (Default Mode Network) and cognitive (Left Fronto-Parietal Network and Dorsal Attention Network) RSNs. Our findings suggest that maladaptive/dysfunctional processing of negative emotions and visceral sensitivity may occur in patients with CD.

Effects of psychological stress on inflammatory bowel disease via affecting the microbiota-gut-brain axis

ABSTRACT

Inflammatory bowel disease (IBD) is an idiopathic intestinal inflammatory condition with chronic and relapsing manifestations and is characterized by a disturbance in the interplay between the intestinal microbiota, the gut, and the brain. The microbiota-gut-brain axis involves interactions among the nervous system, the neuroendocrine system, the gut microbiota, and the host immune system. Increasing published data indicate that psychological stress exacerbates the severity of IBD due to its negative effects on the microbiota-gut-brain axis, including alterations in the stress response of the hypothalamic-pituitary-adrenal (HPA) axis, the balance between the sympathetic nervous system and vagus nerves, the homeostasis of the intestinal flora and metabolites, and normal intestinal immunity and permeability. Although the current evidence is insufficient, psychotropic agents, psychotherapies, and interventions targeting the microbiota-gut-brain axis show the potential to improve symptoms and quality of life in IBD patients. Therefore, further studies that translate recent findings into therapeutic approaches that improve both physical and psychological well-being are needed.

Greater Fatigue and Reduced Neurocognitive Speed With Symptomatic Crohn's Disease

Background

While patients with Crohn's disease commonly report fatigue, an association of Crohn's disease with mild neurocognitive impairment has also been suggested. This study investigated the relationship between Crohn's disease activity, fatigue, and neurocognitive functioning.

Methods

In this cross-sectional study, adults with Crohn's disease (n = 25) and healthy controls (n = 26) completed the PROMIS Fatigue 7a form and Multidimensional Fatigue Inventory and neurocognitive testing across 6 domains. Symptomatic and endoscopic remission were assessed with a short Crohn's Disease Activity Index and Simple Endoscopic Score for Crohn's Disease. Linear regression adjusting for age and sex was used to compare fatigue and neurocognition among patients with Crohn's disease versus controls and those with active Crohn's disease versus those in remission.

Results

Compared to controls, adults with Crohn's disease reported greater overall and domain-specific fatigue (general, physical, and mental) (P < .05 for all comparisons). Patients in symptomatic remission had significantly less fatigue (P < .05). No differences were found in neurocognitive accuracy or speed between Crohn's disease and controls. Disease activity was not associated with accuracy on neurocognitive testing; however, patients with symptomatic Crohn's disease had longer correct response times for social cognition and episodic memory compared to asymptomatic patients (P < .05). Endoscopic disease activity was associated with longer correct response times for tasks linked to social cognition, episodic memory, and complex cognition (P < .05). These differences persisted after adjusting for fatigue.

Conclusions

Patients with symptomatic Crohn's disease experience greater fatigue and have slower response times on neurocognitive testing. However, fatigue does not appear to mediate the slower response times.

Altered Function and Structure of the Cerebellum Associated with Gut-Brain Regulation in Crohn's Disease: a Structural and Functional MRI Study

This study employed structural and functional magnetic resonance imaging (MRI) to investigate changes in the function and structure of the cerebellum associated with gut-brain axis (GBA) regulation in patients diagnosed with Crohn's disease (CD). The study comprised 20 CD patients, including 12 with active disease (CD-A) and 8 in remission (CD-R), as well as 21 healthy controls. Voxel-based morphometry (VBM) was utilized for structural analysis of cerebellar gray matter volume, while independent component analysis (ICA) was applied for functional analysis of cerebellar functional connectivity (FC). The results showed significant GMV reduction in the left posterior cerebellar lobe across all CD patients compared to HCs, with more pronounced differences in the CD-A subgroup. Additionally, an increase in mean FC of the cerebellar network was observed in all CD patients, particularly in the CD-A subgroup, which demonstrated elevated FC in the vermis and bilateral posterior cerebellum. Correlation analysis revealed a positive relationship between cerebellar FC and the Crohn's Disease Activity Index (CDAI) and a trend toward a negative association with the reciprocal of the Self-rating Depression Scale (SDS) score in CD patients. The study's findings suggest that the cerebellum may play a role in the abnormal regulation of the GBA in CD patients, contributing to a better understanding of the neural mechanisms underlying CD and highlighting the cerebellum's potential role in modulating gut-brain interactions.

Not All Stroop-Type Tasks Are Alike: Assessing the Impact of Stimulus Material, Task Design, and Cognitive Demand via Meta-analyses Across Neuroimaging Studies

The Stroop effect is one of the most often studied examples of cognitive conflict processing. Over time, many variants of the classic Stroop task were used, including versions with different stimulus material, control conditions, presentation design, and combinations with additional cognitive demands. The neural and behavioral impact of this experimental variety, however, has never been systematically assessed. We used activation likelihood meta-analysis to summarize neuroimaging findings with Stroop-type tasks and to investigate whether involvement of the multiple-demand network (anterior insula, lateral frontal cortex, intraparietal sulcus, superior/inferior parietal lobules, midcingulate cortex, and pre-supplementary motor area) can be attributed to resolving some higher-order conflict that all of the tasks have in common, or if aspects that vary between task versions lead to specialization within this network. Across 133 neuroimaging experiments, incongruence processing in the color-word Stroop variant consistently recruited regions of the multiple-demand network, with modulation of spatial convergence by task variants. In addition, the neural patterns related to solving Stroop-like interference differed between versions of the task that use different stimulus material, with the only overlap between color-word, emotional picture-word, and other types of stimulus material in the posterior medial frontal cortex and right anterior insula. Follow-up analyses on behavior reported in these studies (in total 164 effect sizes) revealed only little impact of task variations on the mean effect size of reaction time. These results suggest qualitative processing differences among the family of Stroop variants, despite similar task difficulty levels, and should carefully be considered when planning or interpreting Stroop-type neuroimaging experiments.

Burden of delirium on mortality and healthcare resource utilization in geriatric patients hospitalized for inflammatory bowel disease

Background

Delirium is prevalent in elderly patients, linked to elevated mortality rates, heightened healthcare resource use, and caregiver burden. Inflammatory bowel disease (IBD) poses various delirium risk factors, yet the impact on geriatric IBD patient outcomes remains unexplored.

Methods

Using 2016-2019 National Inpatient Sample data, we identified ≥65-year-old patients admitted for IBD (Crohn's, ulcerative colitis) management stratified by delirium presence as a secondary diagnosis. The study aimed to assess delirium's impact on geriatric IBD patient outcomes.

Results

Among 67,534 elderly IBD admissions, 0.7% (470) developed delirium. The delirium group had a 4.8-fold increase in in-hospital mortality risk (odds ratio 4.80, P < 0.001, 95% confidence interval [CI] 1.94-11.8). IBD patients with delirium experienced prolonged length of stay (adjusted mean difference 5.15 days, 95% CI 3.24-7.06, P < 0.001) and increased care costs (adjusted mean difference $48,328, 95% CI $26,485-$70,171, P < 0.001) compared to those without delirium.

Conclusion

Elderly IBD patients with delirium face higher mortality risk, prolonged hospitalization, and increased healthcare costs. Clinicians should recognize delirium's detrimental effects in this vulnerable group and adhere to preventive protocols for improved care.

Altered resting-state brain functional activities and networks in Crohn's disease: a systematic review

Background

Crohn's disease (CD) is a non-specific chronic inflammatory disease of the gastrointestinal tract and is a phenotype of inflammatory bowel disease (IBD). The current study sought to compile the resting-state functional differences in the brain between CD patients and healthy controls.

Methods

The online databases PubMed, Web of Science Core, and EMBASE were used to find the published neuroimage studies. The search period was from the beginning through December 15, 2023. The predetermined inclusion and exclusion criteria allowed for the identification of the studies. The studies were assembled by two impartial reviewers, who also assessed their quality and bias.

Results

This review comprised 16 resting-state fMRI studies in total. The included studies generally had modest levels of bias. According to the research, emotional processing and pain processing were largely linked to increased or decreased brain activity in patients with CD. The DMN, CEN, and limbic systems may have abnormalities in patients with CD, according to research on brain networks. Several brain regions showed functional changes in the active CD group compared to the inactive CD group and the healthy control group, respectively. The abnormalities in brain areas were linked to changes in mood fluctuations (anxiety, melancholy) in patients with CD.

Conclusion

Functional neuroimaging helps provide a better understanding of the underlying neuropathological processes in patients with CD. In this review, we summarize as follows: First, these findings indicate alterations in brain function in patients with CD, specifically affecting brain regions associated with pain, emotion, cognition, and visceral sensation; second, disease activity may have an impact on brain functions in patients with CD; and third, psychological factors may be associated with altered brain functions in patients with CD.

An examination of resting-state functional connectivity in patients with active Crohn's disease

Background

Alterations in resting state functional connectivity (rs-FC) in Crohn's Disease (CD) have been documented in default mode network (DMN) and frontal parietal network (FPN) areas, visual, cerebellar, salience and attention resting-state-networks (RSNs), constituting a CD specific neural phenotype. To date, most studies are in patients in remission, with limited studies in active disease.

Methods

Twenty five active CD cases and 25 age-, BMI- and gender-matched healthy controls (HC) were recruited to a resting-state-functional Magnetic Resonance Imaging (rs-fMRI) study. Active disease was defined as C-reactive protein>5 mg/dL, faecal calprotectin>250 μg/g, or through ileocolonoscopy or MRE. rs-fMRI data were analysed using independent component analysis (ICA) and dual regression. Differences in RSNs between HCs and active CD were assessed, and rs-FC was associated with disease duration and abdominal pain.

Results

Increased connectivity in the FPN (fusiform gyrus, thalamus, caudate, posterior cingulate cortex, postcentral gyrus) and visual RSN (orbital frontal cortex) were observed in CD versus HC. Decreased activity was observed in the salience network (cerebellum, postcentral gyrus), DMN (parahippocampal gyrus, cerebellum), and cerebellar network (occipital fusiform gyrus, cerebellum) in CD versus HCs. Greater abdominal pain scores were associated with lower connectivity in the precuneus (visual network) and parietal operculum (salience network), and higher connectivity in the cerebellum (frontal network). Greater disease duration was associated with greater connectivity in the middle temporal gyrus and planum temporale (visual network).

Conclusion

Alterations in rs-FC in active CD in RSNs implicated in cognition, attention, emotion, and pain may represent neural correlates of chronic systemic inflammation, abdominal pain, disease duration, and severity.

Distinct Alterations in Central Pain Processing of Visceral and Somatic Pain in Quiescent Ulcerative Colitis Compared to Irritable Bowel Syndrome and Health

BACKGROUND AND AIMS

Despite relevance to pain chronicity, disease burden, and treatment, mechanisms of pain perception for different types of acute pain remain incompletely understood in patients with inflammatory bowel disease [IBD]. Building on experimental research across pain modalities, we herein addressed behavioural and neural correlates of visceral versus somatic pain processing in women with quiescent ulcerative colitis [UC] compared to irritable bowel syndrome [IBS] as a patient control group and healthy women [HC].

METHODS

Thresholds for visceral and somatic pain were assessed with rectal distensions and cutaneous thermal pain, respectively. Using functional magnetic resonance imaging, neural and behavioural responses to individually calibrated and intensity-matched painful stimuli from both modalities were compared.

RESULTS

Pain thresholds were comparable across groups, but visceral thresholds correlated with gastrointestinal symptom severity and chronic stress burden exclusively within UC. Upon experience of visceral and somatic pain, both control groups demonstrated enhanced visceral pain-induced neural activation and greater perceived pain intensity, whereas UC patients failed to differentiate between pain modalities at both behavioural and neural levels.

CONCLUSIONS

When confronted with acute pain from multiple bodily sites, UC patients' responses are distinctly altered. Their failure to prioritise pain arising from the viscera may reflect a lack of adaptive behavioural flexibility, possibly resulting from long-lasting central effects of repeated intestinal inflammatory insults persisting during remission. The role of psychological factors, particularly chronic stress, in visceral sensitivity and disease-specific alterations in the response to acute pain call for dedicated mechanistic research as a basis for tailoring interventions for intestinal and extraintestinal pain symptoms in IBD.

Exploring neural activity in inflammatory bowel diseases using functional connectivity and DKI-fMRI fusion

Although MRI has made considerable progress in Inflammatory bowel disease (IBD), most studies have concentrated on data information from a single modality, and a better understanding of the interplay between brain function and structure, as well as appropriate clinical aids to diagnosis, is required. We calculated functional connectivity through fMRI time series using resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion kurtosis imaging (DKI) data from 27 IBD patients and 29 healthy controls. Through the DKI data of each subject, its unique structure map is obtained, and the relevant indicators are projected onto the structure map corresponding to each subject by using the graph Fourier transform in the grasp signal processing (GSP) technology. After the features are optimized, a classical support vector machine is used to classify the features. IBD patients have altered functional connectivity in the default mode network (DMN) and subcortical network (SCN). At the same time, compared with the traditional brain network analysis, in the test of some indicators, the average classification accuracy produced by the framework method is 12.73% higher than that of the traditional analysis method. This paper found that the brain network structure of IBD patients in DMN and SCN has changed. Simultaneously, the application of GSP technology to fuse functional information and structural information is superior to the traditional framework in classification, providing a new perspective for subsequent clinical auxiliary diagnosis.

Has the COVID-19 Pandemic Worsened Health-Related Quality of Life of Patients with Inflammatory Bowel Disease? A Longitudinal Disease Activity-Controlled Study

The present longitudinal study aimed to investigate the burden of disease activity change on health-related quality of life (HRQoL) of patients with inflammatory bowel disease (IBD) during the two different pandemic waves in 2020 and 2021. A sample of 221 IBD patients (recruited during March-May 2020 for T0 and March-May 2021 for T1) was included. The psychological impact of the COVID-19 pandemic (Impact of Event Scale-Revised (IES-R)) and HRQoL (Inflammatory Bowel Disease Questionnaire (IBDQ)) were assessed. Post-traumatic COVID-19-related symptoms (IES-R) were not significantly different across the disease activity-related groups. Conversely, IBDQ was consistently higher in patients with persistent, quiescent disease activity compared to the other groups, as expected. Even after controlling for baseline IES-R, repeated-measures ANCOVA showed a non-significant main effect of time (p = 0.60) but a significant time-per-group interaction effect with a moderate effect size (η2 = 0.08). During the two different phases of pandemic restrictions, IBD-specific HRQoL was modified by disease-related factors such as disease activity, rather than by the post-traumatic symptoms of COVID-19. This lends further weight to the need for developing an evidence-based, integrated, biopsychosocial model of care for patients with IBD to identify subjective and objective factors that affect the burden of disease.

The relationship between Central Nervous System morphometry changes and key symptoms in Crohn’s disease

Alterations in grey matter volume (GMV) and cortical thickness (CT) in Crohn’s disease (CD) patients has been previously documented. However, the findings are inconsistent, and not a true representation of CD burden, as only CD patients in remission have been studied thus far. We investigate alterations in brain morphometry in patients with active CD and those in remission, and study relationships between brain structure and key symptoms of fatigue, abdominal pain, and extraintestinal manifestations (EIM). Magnetic Resonance Imaging brain scans were collected in 89 participants; 34 CD participants with active disease, 13 CD participants in remission and 42 healthy controls (HCs); Voxel based morphometry (VBM) assessed GMV and white matter volume (WMV), and surface-based analysis assessed cortical thickness (CT). We show a significant reduction in global cerebrospinal fluid (CSF) volume in CD participants compared with HCs, as well as, a reduction in regional GMV, WMV and CT in the left precentral gyrus (motor cortex), and an increase in GMV in the frontal brain regions in CD compared with HCs. Atrophy of the supplementary motor area (SMA) was associated with greater fatigue in CD. We also show alterations in brain structure in multiple regions in CD associated with abdominal pain and extraintestinal inflammations (EIMs). These brain structural alterations likely reflect neuroplasticity to a chronic systemic inflammatory response, abdominal pain, EIMs and fatigue. These findings will aid our understanding of the cross-linking between chronic inflammation, brain structural changes and key unexplained CD symptomatology like fatigue.

Disease course and treatment outcomes of Crohn's disease patients with early or late surgery - A Danish nationwide cohort study from 1997 to 2015

BACKGROUND

Studies on early surgery among Crohn's disease patients are few and focus on ileocolonic resections.

AIM

The aim of this nationwide cohort study was to investigate the disease course in all Crohn's disease patients who underwent early and late major abdominal surgery.

METHODS

In a Danish nationwide cohort of Crohn's disease patients from 1997 to 2015 we included 493 patients (group 1) resected within 29 days, 472 patients (group 2) resected between 30 and 180 days, and 1,518 patients (group 3) resected after 180 days of diagnosis. Re-operation, hospitalisations and medications were analysed.

RESULTS

The cumulative risk of re-operation was lower among patients from group 1 (five-year risk: 16.5% vs. group 2: 18.2% and group 3: 21.2%, p = 0.004). Fewer patients from group 2 and 3 required hospitalisations (269 (56.5%) and 803 (52.8%) vs. group 1: 329 (66.8%) p<0.001). Patients from group 3 had a higher cumulative use of immunomodulators in the first three years after initial surgery (one-year risk: 24.6% vs. group 1: 19.4% and group 2: 17.0%, p<0.001).

CONCLUSION

Crohn's disease patients resected within 29 days of diagnosis had a lower cumulative risk of re-operation and a lower cumulative exposure to immunomodulators in the initial years after surgery.

Psychological stress in inflammatory bowel disease: Psychoneuroimmunological insights into bidirectional gut–brain communications

Inflammatory bowel disease (IBD), mainly including ulcerative colitis (UC) and Crohn’s disease (CD), is an autoimmune gastrointestinal disease characterized by chronic inflammation and frequent recurrence. Accumulating evidence has confirmed that chronic psychological stress is considered to trigger IBD deterioration and relapse. Moreover, studies have demonstrated that patients with IBD have a higher risk of developing symptoms of anxiety and depression than healthy individuals. However, the underlying mechanism of the link between psychological stress and IBD remains poorly understood. This review used a psychoneuroimmunology perspective to assess possible neuro-visceral integration, immune modulation, and crucial intestinal microbiome changes in IBD. Furthermore, the bidirectionality of the brain–gut axis was emphasized in the context, indicating that IBD pathophysiology increases the inflammatory response in the central nervous system and further contributes to anxiety- and depression-like behavioral comorbidities. This information will help accurately characterize the link between psychological stress and IBD disease activity. Additionally, the clinical application of functional brain imaging, microbiota-targeted treatment, psychotherapy and antidepressants should be considered during the treatment and diagnosis of IBD with behavioral comorbidities. This review elucidates the significance of more high-quality research combined with large clinical sample sizes and multiple diagnostic methods and psychotherapy, which may help to achieve personalized therapeutic strategies for IBD patients based on stress relief.

Altered mean apparent propagator-based microstructure and the corresponding functional connectivity of the parahippocampus and thalamus in Crohn’s disease

Crohn’s disease (CD) is a chronic and relapsing inflammatory bowel disorder that has been shown to generate neurological impairments, which has the potential to signify disease activity in an underlying neurological manner. The objective of this study was to investigate the abnormalities of brain microstructure and the corresponding functional connectivity (FC) in patients with CD, as well as their associations with disease condition. Twenty-two patients with CD and 22 age-, gender-, and education-matched healthy controls (HCs) were enrolled in this study. All subjects underwent mean apparent propagator (MAP)-MRI and resting-state functional magnetic resonance imaging (MRI) (rs-fMRI) data collection. Each patient was evaluated clinically for the condition and duration of the disease. The MAP metrics were extracted and compared between two groups. Pearson’s correlation analysis was conducted to determine the relationship between disease characteristics and significantly abnormal MAP metrics in the CD group. Regions of interest (ROIs) for ROI-wise FC analysis were selected based on their correlation with MAP metrics. Results showed that multiple brain regions, including the parahippocampus and thalamus, exhibited statistically significant differences in MAP metrics between CD patients and HCs. Additionally, CD patients exhibited decreased FC between the left parahippocampus and bilateral thalamus, as well as the right parahippocampus and bilateral thalamus. The findings of this work provide preliminary evidence that structural abnormalities in the parahippocampal gyrus (PHG) and thalamus, as well as decreased FC between them, may reflect the degree of inflammatory of the disease and serve as brain biomarkers for evaluating CD activity.

Impact of the COVID‐19 pandemic on inflammatory bowel disease: The role of emotional stress and social isolation

Inflammatory bowel disease (IBD) is a chronic health condition exacerbated by negative emotional stress experiences. In the current study, we examined whether the outbreak of the COVID-19 pandemic coincided with an increase in stress experiences and accordingly an aggravation of disease activity in IBD patients. Sixty-three IBD patients (30 Crohn's disease or CD, 33 ulcerative colitis) completed an online survey during the COVID-19-related lockdown, assessing clinical disease activity, disease-related quality of life, presence of functional gastrointestinal symptoms, social isolation and stress experiences. Scores were then compared to pre-lockdown baseline screening. The pandemic yielded a significant baseline-to-lockdown increase in emotional stress and social isolation. Stress increments, particularly those occasioned by interpersonal tension and excessive interpersonal proximity, were associated with a worsening of functional gastrointestinal symptoms. Exacerbations of loneliness coincided with an escalation of CD activity, functional gastrointestinal symptoms and a decline in subjective health. Lastly, COVID-19 anxiety was significantly related to CD symptom severity and social dysfunction. The findings show that shifts in IBD expression are closely linked to changes in emotional stress experiences and interpersonal relatedness. As such, they contribute to a better understanding of inter-individual differences in IBD progression and provide leads for therapeutic interventions.

Altered Intra- and Inter-Network Functional Connectivity in Patients With Crohn’s Disease: An Independent Component Analysis-Based Resting-State Functional Magnetic Resonance Imaging Study

Background

Many studies have reported changes in the structure and function of several brain areas in patients with Crohn’s disease (CD). However, little is known about whether the possible functional connectivity of resting-state networks (RSNs) is altered in CD patients.

Purpose

Aim to investigate the intra- and inter-network alterations between related RSNs in patients with CD and the potential relationships between altered neuroimaging and CD clinical indices.

Materials and Methods

In this study, 20 CD patients and 22 age- and sex-matched healthy controls were included. All participants underwent functional magnetic resonance imaging examination. We used independent component analysis (ICA) to explore the changes in RSNs and evaluated functional connectivity between different RSNs using functional network connectivity (FNC) analysis, and Pearson correlation analysis was performed between altered intra- and inter-network functional connectivity and CD clinical index.

Results

Six CD-related RSNs were identified via ICA, namely the high visual, prime visual, language, dorsal default mode, posterior insula, and precuneus networks. Compared to healthy controls, patients with CD showed significant changes in prime visual and language networks. Additionally, the functional connectivity (FC) values of the left calcarine within the prime visual network were negatively correlated with CD duration. The inter-alterations showed that a significantly increased FNC existed between the language and dorsal default mode networks.

Conclusion

The results showed CD-related changes in brain functional networks. This evidence provides more insights into the pathophysiological mechanisms of brain plasticity in CD.

Supraspinal Mechanisms of Intestinal Hypersensitivity

Gut inflammation or injury causes intestinal hypersensitivity (IHS) and hyperalgesia, which can persist after the initiating pathology resolves, are often referred to somatic regions and exacerbated by psychological stress, anxiety or depression, suggesting the involvement of both the spinal cord and the brain. The supraspinal mechanisms of IHS remain to be fully elucidated, however, over the last decades the series of intestinal pathology-associated neuroplastic changes in the brain has been revealed, being potentially responsible for the phenomenon. This paper reviews current clinical and experimental data, including the authors' own findings, on these functional, structural, and neurochemical/molecular changes within cortical, subcortical and brainstem regions processing and modulating sensory signals from the gut. As concluded in the review, IHS can develop and maintain due to the bowel inflammation/injury-induced persistent hyperexcitability of viscerosensory brainstem and thalamic nuclei and sensitization of hypothalamic, amygdala, hippocampal, anterior insular, and anterior cingulate cortical areas implicated in the neuroendocrine, emotional and cognitive modulation of visceral sensation and pain. An additional contribution may come from the pathology-triggered dysfunction of the brainstem structures inhibiting nociception. The mechanism underlying IHS-associated regional hyperexcitability is enhanced NMDA-, AMPA- and group I metabotropic receptor-mediated glutamatergic neurotransmission in association with altered neuropeptide Y, corticotropin-releasing factor, and cannabinoid 1 receptor signaling. These alterations are at least partially mediated by brain microglia and local production of cytokines, especially tumor necrosis factor α. Studying the IHS-related brain neuroplasticity in greater depth may enable the development of new therapeutic approaches against chronic abdominal pain in inflammatory bowel disease.

Alterations of Regional Homogeneity in Crohn's Disease With Psychological Disorders: A Resting-State fMRI Study

Abnormal psychological processing in the central nervous system has been found in Crohn's disease (CD) patients. Resting-state functional magnetic resonance images of 57 inactive and 58 active CD patients, and 92 healthy controls (HC) were obtained. The psychological assessment used a psychological questionnaire that was collected within 1 week before functional MRI examination. We investigated the neural basis of CD patients and the correlation among regional homogeneity (ReHo), clinical features and psychological assessment scores. We found that more severe psychological assessment disorder scores were observed in the active CD group than in the inactive CD group and HC group (P<0.001). Compared with HC, the active CD patients exhibited higher ReHo values in the frontal superior medial, frontal middle and lower values in the postcentral, supplementary motor area, and temporal middle. Meanwhile, inactive CD patients exhibited higher ReHo values in the frontal middle and lower ReHo values in the precentral, postcentral and putamen (all voxel P< 0.001, cluster P<0.01, corrected). The values of the frontal superior medial, postcentral and supplementary motor area were correlation with psychological assessment scores (r = 0.38, −0.41, −0.32, P = 0.001, 0.014, 0.003), and the clinical features of simple endoscopic score for Crohn's disease and erythrocyte sedimentation rate were negatively correlated with psychological assessment scores in active CD patients (r = −0.35, −0.34, P = 0.06, 0.08). These results provide evidence for abnormal resting-state brain activity in CD and suggest that the psychological of CD may play a critical role in brain function.

Is It a Gut Feeling? Bodily Sensations Associated With the Experience of Valence and Arousal in Patients With Inflammatory Bowel Disease

BACKGROUND

Previous studies have shown dysfunctional emotion processing in patients with inflammatory bowel diseases (IBD), characterized by a hypersensitivity to negative emotions and a hyposensitivity to positive emotions. Models of emotion processing emphasize the importance of bodily sensations to the experience of emotions. Since there have been no studies on whether emotion-associated bodily sensations are changed in IBD, we investigated the experience of bodily sensations related to valence and arousal, together with their links to emotional awareness, as one domain of interoceptive sensibility relevant to emotion processing.

METHODS

Using a topographical self-report measure, 41 IBD patients in clinical remission and 44 healthy control (HC) participants were asked to indicate where and how intensely in their body they perceive changes when experiencing emotions of positive and negative valence, as well as relaxation and tension. Additionally, we used self-report questionnaires to assess emotional awareness as one domain of an individual's interoceptive sensibility, gastrointestinal-specific anxiety (GSA), and psychological distress.

RESULTS

Patients with IBD reported higher emotional awareness but lower intensities of perceived changes in their bodily sensations related to valence and arousal of emotional processing. IBD patients reported less intense bodily activation during positive emotions and less intense bodily deactivation during negative emotional states in comparison to HC participants. Higher emotional awareness and psychological distress were linked to stronger experiences of emotion-related bodily sensations in IBD patients.

CONCLUSION

Inflammatory bowel diseases patients exhibited alterations in how they link bodily sensations to their emotional experience. Such persistent changes can affect a patient's wellbeing and are related to higher levels of anxiety and depression among IBD patients, even in remission.

Altered Brain Structure in Chronic Visceral Pain: Specific Differences in Gray Matter Volume and Associations With Visceral Symptoms and Chronic Stress

Structural brain alterations in chronic pain conditions remain incompletely understood, especially in chronic visceral pain. Patients with chronic-inflammatory or functional bowel disorders experience recurring abdominal pain in concert with other gastrointestinal symptoms, such as altered bowel habits, which are often exacerbated by stress. Despite growing interest in the gut-brain axis and its underlying neural mechanisms in health and disease, abnormal brain morphology and possible associations with visceral symptom severity and chronic stress remain unclear. We accomplished parallelized whole-brain voxel-based morphometry analyses in two patient cohorts with chronic visceral pain, i.e., ulcerative colitis in remission and irritable bowel syndrome, and healthy individuals. In addition to analyzing changes in gray matter volume (GMV) in each patient cohort vs. age-matched healthy controls using analysis of covariance (ANCOVA), multiple regression analyses were conducted to assess correlations between GMV and symptom severity and chronic stress, respectively. ANCOVA revealed reduced GMV in frontal cortex and anterior insula in ulcerative colitis compared to healthy controls, suggesting alterations in the central autonomic and salience networks, which could however not be confirmed in supplemental analyses which rigorously accounted for group differences in the distribution of sex. In irritable bowel syndrome, more widespread differences from healthy controls were observed, comprising both decreased and increased GMV within the sensorimotor, central executive and default mode networks. Associations between visceral symptoms and GMV within frontal regions were altered in both patient groups, supporting a role of the central executive network across visceral pain conditions. Correlations with chronic stress, on the other hand, were only found for irritable bowel syndrome, encompassing numerous brain regions and networks. Together, these findings complement and expand existing brain imaging evidence in chronic visceral pain, supporting partly distinct alterations in brain morphology in patients with chronic-inflammatory and functional bowel disorders despite considerable overlap in symptoms and comorbidities. First evidence pointing to correlations with chronic stress in irritable bowel syndrome inspires future translational studies to elucidate the mechanisms underlying the interconnections of stress, visceral pain and neural mechanisms of the gut-brain axis.

Comprehensive Lifestyle Modification Influences Medium-Term and Artificially Induced Stress in Ulcerative Colitis-A Sub-Study within a Randomized Controlled Trial Using the Trier Social Stress Test

OBJECTIVE

The present study presents long-term results of stress-related outcomes of a prospective RCT that evaluated effects of a ten-week comprehensive lifestyle-modification program (LSM) in patients with inactive ulcerative colitis (UC). In addition, exploratory results of a sub-study applying a laboratory stress protocol (Trier Social Stress Test; TSST) conducted within the RCT are reported.

METHODS

Ninety-seven patients with inactive UC were randomized to LSM (n = 47; 50.28 ± 11.90 years; 72.3% female) or self-care (n = 50; 45.54 ± 12.49 years; 70% female). Patients' perceived stress, anxiety, flourishing and depression were assessed at week 0, 12, 24 and 48. After the respective intervention, 16 female patients (LSM: n = 8; 44.6 ± 14.3 years; Self-care: n = 8; 49.25 ± 4.30 years) additionally underwent the TSST. State anxiety, blood pressure, pulse, complete blood counts, adrenocorticotropic hormone (ACTH), cortisol, adrenalin and noradrenalin were measured at baseline (-15 min), stress (+10 min), recovery1 (+20 min) and recovery2 (+55 min). Statistical significance was set at p < 0.05; for the exploratory sub-study using the TSST, p-values < 0.10 were considered significant.

RESULTS

Patients' perceived stress declined significantly after the LSM (p < 0.001) compared with control. This lasted until week 24 (p = 0.023) but did not persist until week 48 (p = 0.060). After 48 weeks, patients' flourishing was significantly increased compared with control (p = 0.006). In response to the TSST, significant group differences were evident for pulse (p = 0.015), adrenaline (p = 0.037) and anxiety (p = 0.066). After 55 min, group differences were found for ACTH (p = 0.067) and systolic blood pressure (p = 0.050).

CONCLUSIONS

LSM has a medium-term positive effect on perceived stress. First indications show that it is promising to investigate these effects further under laboratory conditions. It is also desirable to find out how the effects of LSM can be maintained in the long term.

Brain functional changes in patients with Crohn's disease: A resting-state fMRI study

BACKGROUND

Crohn's disease (CD) is a chronic recurrent intestinal inflammatory disease, often accompanied by poor adaptation and excessive stress response. However, the potential neurological mechanisms of these symptoms have not yet been studied in-depth.

OBJECTIVE

To investigate alterations in brain activity in patients with Crohn's disease and study the relationship between altered regions and clinical indices.

METHODS

A total of 15 CD patients and 26 matched healthy controls were recruited. All participants underwent fMRI scans. The amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) assessed differences in spontaneous regional brain activity. Differences between the groups were selected as seeds for functional connectivity (FC) analyses. Correlations between disease duration and ALFF/ReHo/FC values in abnormal regions were analyzed.

RESULTS

Patients with CD had significantly higher ALFF values in the left superior frontal gyrus, anterior cingulate cortex, and supplementary motor area, and lower values in the left hippocampus. They also had higher ReHo values in the left anterior cingulate cortex, supplementary motor area, putamen, and the bilateral superior frontal gyri. FC strength in the left precentral and middle temporal gyri was found to be increased when the left superior frontal gyrus was used as the seed point. FC strength was also observed to be increased in the left postcentral, middle frontal gyri, inferior frontal orbital cortex, and right rolandic operculum when the left anterior cingulate cortex was used as the seed point.

CONCLUSION

CD demonstrated abnormal neural activity and FC in various regions primarily associated with emotional, pain and cognitive-related functions, which provides more information to further understand the neural mechanisms of the disease.

Higher Levels of Psychological Burden and Alterations in Personality Functioning in Crohn's Disease and Ulcerative Colitis

Aims: Is there evidence for increased psychological distress and alterations in personality functioning in patients with Crohn’s disease (CD) and ulcerative colitis (UC) compared to healthy controls (HCs)?

Background: In patients with CD and UC, perceived stress is closely associated with changes in disease activity. The stress response is influenced by psychological burden and personality functioning, but only little is known about these factors in inflammatory bowel diseases (IBD).

Study: A total of 62 patients with an endoscopic ensured CD/UC without remission (n = 31 per group) and 31 HC were included. Patients with an active CD/UC and HC were individually matched (n = 93, 31 per group) for age, sex, education, and disease activity. Depression and anxiety were assessed to evaluate the effect of psychological burden (Patient Health Questionnaire-9/PHQ-9, Generalized Anxiety Disorder-7/GAD-7). Personality functioning was measured by validated questionnaires for psychodynamic structural characteristics, mentalization, and attachment (Operationalized Psychodynamic Diagnosis-Structure Questionnaire/OPD-SQ, Mentalization Questionnaire/MZQ, and Experiences in Close Relationships scale/ECR-RD 12).

Results: Levels of depression and anxiety were higher in CD/UC patients than in HC with large effect sizes. Comparing personality functioning in CD/UC with HC, psychodynamic structural characteristics differed between CD/UC and HC with medium effect sizes, with structural differences occurring primarily in the domain of self-perception and regulation. Only minor differences were found regarding mentalization and attachment. CD and UC differed only with small effect sizes.

Conclusion: Our data show that compared to HC, patients with CD/UC are characterized by a higher level of psychological burden and structural alterations in the domain of self.

Exploring joint patterns of brain structure and function in inflammatory bowel diseases using multimodal data fusion

BACKGROUND

A growing number of neuroimaging studies suggest distinct neural changes in inflammatory bowel diseases (IBDs). Whether such changes may show similar spatial patterns across distinct neural features within and between specific IBD is unclear. To address this question, we used multivariate multimodal data fusion analysis to investigate structure/function modulation in remitted patients with Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

Patients with IBD (n = 46; n = 31 with CD, n = 15 with UC) in stable remission and 17 healthy controls (HC) underwent structural magnetic resonance imaging (sMRI) and resting-state functional magnetic resonance imaging (rs-fMRI) as well as cognitive testing. Anxiety, depression, and fatigue were assessed using self-rating questionnaires. sMRI data were analyzed via voxel-based morphometry (VBM) and rs-fMRI data via amplitude of low-frequency fluctuations (ALFFs) and regional homogeneity (ReHo). Detection of cross-information between VBM, ALFF, and ReHo was conducted by means of a joint independent component analysis (jICA), followed by group-inference statistics.

KEY RESULTS

Joint independent component analysis detected structural alterations in middle frontal and temporal regions (VBM), and functional changes in the superior frontal gyrus (ReHo) and the medial as well as inferior frontal, inferior temporal, rectal, and subcallosal gyrus (ALFF). One joint component of extracted features of the three modalities differed significantly between IBD patients and controls (p = 0.03), and most distinctly between HC and patients with UC.

CONCLUSIONS AND INFERENCES

Using a multivariate data fusion technique, this study provides further evidence to brain alterations in IBD. The data suggest distinct neural differences between CD and UC, particularly in frontotemporal regions.

Structural and functional changes in the brain of patients with Crohn's disease: an activation likelihood estimation meta-analysis

Multiple reports for brain functional and structural alterations in patients with Crohn's disease (CD) were published. The current study aimed to meta-analyze the existing neuroimaging data and hence produce a brain map revealing areas with functional and structural differences between patients with CD and healthy controls. Original studies published until 2019 were identified from Scopus, Web of Science and PubMed databases, and included into the analysis if they reported relevant results from task-related or resting state functional magnetic resonance imaging (fMRI or rsfMRI) or voxel-based morphometry (VBM), in the form of standardized brain coordinates based on whole-brain analysis. The brain coordinates and sample size of significant results were extracted from eligible studies to be meta-analyzed with the activation likelihood estimation method using the GingerALE software. Sixteen original studies comprised of a total of 865 participants fulfilled the inclusion criteria. Compared to healthy controls, patients with CD had reduced resting state brain connectivity in the paracentral lobule and cingulate gyrus as well as reduced grey matter volume in the medial frontal gyrus. No significant results were found vice versa. These neural correlates allow a better understanding on the effects of CD on the pain expectation, emotion, and quality of life of patients and potentially serve as useful biomarkers for evaluating treatment efficacy.

Altered functional connectivity of the amygdala in Crohn's disease

Crohn's disease (CD), a chronic inflammatory bowel disease, involved in brain structural and functional changes, including the amygdala. Amygdala is a key structure in the limbic system and its related circuits are implicated in processing of emotion, pain and sensory. However, limited study of the amygdala is elucidated in CD. This study mainly investigated altered functional connectivity (FC) of the amygdala in CD patients during resting-state. Magnetic resonance imaging scans were acquired from 42 CD patients and 35 healthy controls (HCs). Whole amygdala bilaterally were selected as regions of interest (ROIs). Voxel-based morphometry and FC methods were applied to investigate the differences of structure or intrinsic connectivity of the amygdala between the two groups, separately. Pearson correlations were performed to explore relationships between the clinical characteristics and neuroimaging findings in CD patients. Based on the whole amygdala bilaterally as ROIs, compared with HCs, CD patients showed no statistical differences of grey matter destiny but exhibited decreased FC between the amygdala and insula, parahippocampus, as well as anterior middle cingulate cortex/dorsal anterior cingulate cortex. CD patients had negative correlation between the disease duration and amygdala-insula connectivity. In the patient group, patients with higher anxiety or depression scores revealed increased FC of the amygdala with thalamus and orbitofrontal cortex. Our results reveal that aberrant FC of the amygdala may be involved in processing of visceral pain and sensation, and emotion in CD. These findings may further enhance the understanding of neural mechanisms of CD.

Changes in the anterior cingulate cortex in Crohn's disease: A neuroimaging perspective

INTRODUCTION

Evidence suggests that Crohn's disease (CD) pathophysiology goes beyond the gastrointestinal tract and is also strongly associated with the brain. In particular, the anterior cingulate cortex (ACC), which plays an integral role in the first brain as part of the default mode network (DMN) and pain matrix, shows abnormalities using multiple neuroimaging modalities. This review summarizes nine related studies that investigated changes in the ACC using structural magnetic resonance imaging, resting-state functional magnetic resonance imaging, and magnetic resonance spectroscopy.

METHODS

An extensive PubMed literature search was conducted from 1980 to August 2020. In a review of the articles identified, particular attention was paid to analysis methods, technical protocol characteristics, and specific changes in the ACC.

RESULTS

In terms of morphology, a decrease in gray matter volume and cortical thickness was observed along with an increase in local gyrification index. In terms of function, functional connectivity (FC) within the DMN was increased. FC between the ACC and the amygdala was decreased. Higher amplitudes of low-frequency fluctuation and graph theory results, including connectivity strength, clustering coefficient, and local efficiency, were detected. In terms of neurotransmitter changes, the concentrations of glutamate increased along with a decrease in gamma-aminobutyric acid, providing a rational explanation for abdominal pain. These changes may be attributed to stress, pain, and negative emotions, as well as changes in gut microbiota.

CONCLUSIONS

For patients with CD, the ACC demonstrates structural, functional, and metabolic changes. In terms of clinical findings, the ACC plays an important role in the onset of depression/anxiety and abdominal pain. Therefore, successful modulation of this pathway may guide treatment.

Functional disruption of cortical cingulate activity attenuates visceral hypersensitivity and anxiety induced by acute experimental colitis

Visceral pain is a highly complex experience and is the most common pathological feature in patients suffering from inflammatory gastrointestinal disorders. Whilst it is increasingly recognized that aberrant neural processing within the gut-brain axis plays a key role in development of neurological symptoms, the underlying mechanisms remain largely unknown. Here, we investigated the cortical activation patterns and effects of non-invasive chemogenetic suppression of cortical activity on visceral hypersensitivity and anxiety-related phenotypes in a well-characterized mouse model of acute colitis induced by dextran sulfate sodium (DSS). We found that within the widespread cortical network, the mid-cingulate cortex (MCC) was consistently highly activated in response to innocuous and noxious mechanical stimulation of the colon. Furthermore, during acute experimental colitis, impairing the activity of the MCC successfully alleviated visceral hypersensitivity, anxiety-like behaviors and visceromotor responses to colorectal distensions (CRDs) via downregulating the excitability of the posterior insula (PI), somatosensory and the rostral anterior cingulate cortices (rACC), but not the prefrontal or anterior insula cortices. These results provide a mechanistic insight into the central cortical circuits underlying painful visceral manifestations and implicate MCC plasticity as a putative target in cingulate-mediated therapies for bowel disorders.

Interrogating the Gut-Brain Axis in the Context of Inflammatory Bowel Disease: A Translational Approach

This review examines preclinical and clinical studies relevant to our understanding of how the bidirectional gut-brain axis influences the natural history of inflammatory bowel disease. Preclinical studies provide proof of concept that preexisting behavioral illness, such as depression, results in increased susceptibility to inflammatory stimuli and that commonly used classes of antidepressants protect against this vulnerability. However, clinical studies suggesting behavioral illness as a risk factor for IBD and a protective role for antidepressants have relied primarily on symptom-reporting rather than objective measurements of inflammation. In terms of gut-to-brain signaling, there is emerging evidence from preclinical and clinical observation that intestinal inflammation alters brain functions, including the induction of mood disorders, alteration of circadian rhythm both centrally and peripherally, and changes in appetitive behaviors. Furthermore, preclinical studies suggest that effective treatment of intestinal inflammation improves associated behavioral impairment. Taken together, the findings of this review encourage a holistic approach to the management of patients with IBD, accommodating lifestyle issues that include the avoidance of sleep deprivation, optimized nutrition, and the monitoring and appropriate management of behavioral disorders. The review also acknowledges the need for better-designed clinical studies evaluating the impact of behavioral disorders and their treatments on the natural history of IBD, utilizing hard end points to assess changes in the inflammatory process as opposed to reliance on symptom-based assessments. The findings of the review also encourage a better understanding of changes in brain function and circadian rhythm induced by intestinal inflammation.

Disease course, stress, attachment, and mentalization in patients with inflammatory bowel disease

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, are chronic intestinal disorders that requires lifelong treatments. IBD are associated with perceived stress, poor quality of life, and psychopathological disorders. Previous studies have documented that psychological distress and depression are risk factors for IBD. On the other hand, IBD itself might be a source of psychological stress. IBD negatively affect individuals' daily social interactions and close interpersonal relationships. Despite IBD's detrimental effects on quality of life, patients' adherence to medicaments remains low, increasing the risk of relapses and the subsequent worsening of the clinical condition. Drawing on attachment and mentalization theories, we aim to contribute to understanding of the mechanisms involved in the poor quality of social relationships and the tendency for medication non-adherence in patients with IBD. We hypothesize a bidirectional link between IBD and attachment style and related mentalization abilities, where an individual's attachment style refers to a complex and characteristic pattern of relating to self and others and mentalization refers to the process of inferring one's own and others' mental and physical states. This hypothesized link between IBD and insecure attachment style, mediated by reduced mentalizing abilities, may be a risk factor for developing both IBD-related psychological disorders and reduced medication adherence, which could then lead to worsening disease management and prognoses for the disease course. The medication nonadherence is here considered as both an outcome and a risk factor of this vicious circle. We share the view that preventing the worsening of the IBD condition and promoting patients' medication adherence would be possible by considering the circular relationship between IBD, attachment, and mentalization and by promoting reflective functioning in patients with IBD, from the onset of the disease.

Brain Resting-State Network Alterations Associated With Crohn's Disease

Inflammatory bowel disease (IBD) is a chronic disease that is associated with aspects of brain anatomy and activity. In this preliminary MRI study, we investigated differences in brain structure and in functional connectivity (FC) of brain regions in 35 participants with Crohn's disease (CD) and 21 healthy controls (HC). Voxel-based morphometry (VBM) analysis was performed to contrast CD and HC structural images. Region of interest (ROI) analyses were run to assess FC for resting-state network nodes. Independent component analysis (ICA) identified whole brain differences in FC associated with resting-state networks. Though no structural differences were found, ROI analyses showed increased FC between the frontoparietal (FP) network and salience network (SN), and decreased FC between nodes of the default mode network (DMN). ICA results revealed changes involving cerebellar (CER), visual (VIS), and SN components. Differences in FC associated with sex were observed for both ROI analysis and ICA. Taken together, these changes are consistent with an influence of CD on the brain and serve to direct future research hypotheses.

Alterations in brain white matter microstructural properties in patients with Crohn's disease in remission

Patients with inflammatory bowel disease have been shown to have abnormal brain morphometry or function, which are associated with psychological symptoms such as stress, depression or anxiety. The present work recruited 20 Crohn’s disease patients in remission (CDs) and 20 age-gender-handedness-education matched healthy controls (HCs) and compared their brain white matter microstructural properties using Diffusion Tensor Imaging (DTI). Additionally, we examined the correlations between the microstructural properties and cognition (verbal fluency language task, VF) and affect (anxiety) in both groups as well as disease duration in CDs. Results showed that CDs exhibited significant alterations in microstructural properties compared to HCs in various white matter tracts relevant to language function despite no significant difference in VF scores. Furthermore, CDs’ microstructural changes exhibited correlations with anxiety level and disease duration. These findings suggest that CD patients may experience changes in white matter microstructural properties which may be a biomarker of neuropsychiatric comorbidities of CD.

Stress and the brain-gut axis in functional and chronic-inflammatory gastrointestinal diseases: A transdisciplinary challenge

The broad role of stress in the brain-gut axis is widely acknowledged, with implications for multiple prevalent health conditions that are characterized by chronic gastrointestinal symptoms. These include the functional gastrointestinal disorders (FGID), such as irritable bowel syndrome and functional dyspepsia, as well as inflammatory bowel diseases (IBD) like ulcerative colitis and Crohn's disease. Although the afferent and efferent pathways linking the gut and the brain are modulated by stress, the fields of neurogastroenterology and psychoneuroendocrinology (PNE)/ psychoneuroimmunology (PNI) remain only loosely connected. We aim to contribute to bringing these fields closer together by drawing attention to a fascinating, evolving research area, targeting an audience with a strong interest in the role of stress in health and disease. To this end, this review introduces the concept of the brain-gut axis and its major pathways, and provides a brief introduction to epidemiological and clinical aspects of FGIDs and IBD. From an interdisciplinary PNE/PNI perspective, we then detail current knowledge regarding the role of chronic and acute stress in the pathophysiology of FGID and IBD. We provide an overview of evidence regarding non-pharmacological treatment approaches that target central or peripheral stress mechanisms, and conclude with future directions, particularly those arising from recent advances in the neurosciences and discoveries surrounding the gut microbiota.

Attachment and Mentalizing Abilities in Patients with Inflammatory Bowel Disease

Background

Inflammatory bowel diseases (IBD) are associated with stress, poor quality of life, and attachment insecurity. Mentalization is the human ability to perceive and reason about feelings and psychological dispositions of one's self and others. The chronic disorders are believed to affect patients' mentalizing abilities and to determine a shift towards attachment insecurity in patients affected. In this study, the attachment dimensions and mentalization were assessed in IBD patients and healthy controls. Further knowledge about the interplay among IBD, mentalization, and attachment might shed more light into the psychopathological mechanisms leading to insecurity and vulnerability to stress in IBD.

Methods

A group of 96 IBD patients and 102 healthy controls completed the attachment style questionnaire (ASQ), the reflective functioning questionnaire (RFQ), and the Eyes test, a performance-based measure of mentalization.

Results

Compared to controls, IBD patients have shown more pronounced attachment anxiety and lower scores in the Eyes test. Disease activity was negatively correlated with the Eyes test scores.

Conclusion

These findings have suggested a plausible impact of IBD on mentalization abilities and have provided new insights into the interplay between IBD, deficits in mentalization, and attachment insecurity. IBD patients are highly vulnerable to disease-related stress that may promote impairments in mentalization. Low mentalization might play a central role in the development of attachment insecurity and emotional disturbances in IBD. The present study's results might open new scenarios for psychodynamic approaches to the treatment of the emotional disturbances in IBD based on attachment and mentalization theory.

Vagus Nerve Stimulation at the Interface of Brain-Gut Interactions

The vagus nerve, a key component of the cross-communication between the gut and the brain, is a major element of homeostasis sensing the "milieu intérieur" and boosting the nervous and endocrine responses to maintain the gastrointestinal health status. This nerve has anti-inflammatory properties regulating the gut through the activation of the hypothalamic-pituitary-adrenal axis and the release of cortisol and through a vagovagal reflex, which has an anti-tumor necrosis factor (TNF) effect called the cholinergic anti-inflammatory pathway. Stimulating this nerve is an interesting tool as a nondrug therapy for the treatment of gastrointestinal diseases in which brain-gut communication is dysfunctional, such as inflammatory bowel disorders and others. This review presents the rationale of vagal gastrointestinal physiology and diseases and the most recent advances in vagus nerve stimulation. It also highlights the main issues to be addressed in the future to improve this bioelectronic therapy for gastrointestinal disorders.

Central hypersensitivity - A model for persistent musculoskeletal pain in inflammatory bowel diseases

Pain is reported to affect over 70% of individuals with inflammatory bowel diseases (IBD), with abdominal and musculoskeletal (MSK) pain representing the most common complaints. MSK pain is typically considered within the narrow framework of inflammatory extraintestinal manifestations of IBD, resulting in a limited scope for the nature and underlying mechanisms participating in MSK pain experiences in this population. Symptoms related to central sensitization have recently demonstrated association with active IBD and worse MSK pain experiences, suggesting a potential roll for central mechanisms in MSK-related pain. Current literature exploring persistent pain in chronic inflammatory and MSK populations propose complex pain models comprised of dynamic nervous system relationships influenced by primary disease features and concomitant pain states, as well as affective and cognitive components. Nervous system contributions in the development and maintenance of persistent pain are postulated to include mechanisms of peripheral and central sensitization, changes in descending central modulation, as well as structural brain changes. These models go beyond current MSK pain models described in IBD literature, highlighting the need for new frameworks for considering MSK-related pain in IBD. Consequently, this paper proposes a broader theoretical model whereby central mechanisms, such as central sensitization and grey matter changes, as well as psychological and disease factors are suggested to modulate pain experiences in this population. Exploration of relationships within the proposed framework may provide not only a deeper understanding of the generation and maintenance of persistent MSK pain in IBD, but also highlight the need for new targeted management pathways in this population. This paper hypothesizes that exploration of central sensitization in IBD patients will demonstrate altered somatosensory functioning in patients with MSK pain, and that IBD activity and psychological factors will be associated with altered somatosensory functioning and worse pain experiences.

Implications of the Westernized Diet in the Onset and Progression of IBD

Inflammatory bowel diseases (IBD) are currently considered multifactorial pathologies in which various combined environmental factors act on a genetic background, giving rise to a chronic inflammation of the gastrointestinal tract. Among the various environmental factors, it now seems clear that the diet plays the major role in IBD onset and progression. Several clinical studies have attempted to understand the impact of diet in the development and progression of these diseases in order to establish useful guidelines for their management. However, the modest and sometimes contradictory results did not lead to the definition of shared dietary suggestions. On the other hand, food fads and recommendations based on anecdotal episodes are often followed by IBD patients to improve their diet. This review provides a critical overview of existing data on the role of diet as a risk factor for IBD. The methodology used was that of analyzing the results of clinical studies conducted on diet and IBD over the last 12 years through PubMed, as well as analyzing the most relevant studies on nutrients and their possible roles in IBD through the knowledge of the mechanisms by which they can modulate the microbiota or the intestinal physiology.

Aberrant Brain Function in Active-Stage Ulcerative Colitis Patients: A Resting-State Functional MRI Study

Background: Patients with ulcerative colitis (UC) usually display cognitive impairments, such as memory loss, attention deficits, and declining executive functions, particularly during the active stage of the disease. However, the potential neurological mechanisms of these symptoms remain unclear.

Method: Forty-one patients with mildly to moderately active UC, as well as 42 matched healthy controls, were recruited for an examination using psychological scales, cognitive function tests and resting-state functional magnetic resonance imaging (rs-fMRI). Seed points were identified via analysis of amplitude of low-frequency fluctuation (ALFF), and functional connectivity (FC) was calculated between these seed regions and other voxels in the whole brain. Correlation analyses were performed among clinical indexes, neuropsychological assessments and neuroimaging data.

Result: Compared with the healthy controls, patients with UC exhibited lower ALFF values in the bilateral hippocampal/parahippocampal (HIPP/ParaHIPP) region and higher ALFF values in the left posterior cingulate cortex (PCC.L) and left middle frontal gyrus (MFG.L). With HIPP/ParaHIPP as the seed point, the strengths of the FC in the bilateral middle frontal gyri (MFG), anterior cingulate cortex (ACC), and left caudate nucleus (CAU.L) increased; using the PCC.L as the seed point, the strengths of the FC in the middle cingulate cortex (MCC) and the left angular gyrus (AUG.L) increased. These abnormal brain regions were mainly located in the limbic system. By analyzing the correlations between these brain regions and behavioral data, we observed a close correlation between decreased HIPP/ParaHIPP activity and memory loss; increased PCC activity and strength of FC with the AUG.L were related to dysfunction of executive function and attention network in patients with UC.

Conclusion: Based on these results, the limbic lobe might be the core of the brain-gut axis (BGA) and play an important role in cognitive impairments, suggesting potential mechanisms for cognitive impairment in patients with UC in the active stage of the disease.

Novel Perceived Stress and Life Events Precede Flares of Inflammatory Bowel Disease: A Prospective 12-Month Follow-Up Study

BACKGROUND AND AIMS

Inflammatory bowel disease [IBD] is characterized by recurrent disease flares. The impact of psychosocial wellbeing on the occurrence of flares is unclear. In this prospective study, we aimed to evaluate the association between patient-reported psychosocial wellbeing and disease flares using continuous monitoring.

METHODS

Consecutive IBD patients were recruited from the myIBDcoach telemedicine study cohort. Over 12 months, participants reported on disease activity together with anxiety, depression, fatigue, perceived stress and life events every 1-3 months. Flares were defined using a combination of clinical disease activity and additional measurements. Generalized estimating equation models were used to assess associations between psychosocial wellbeing and flares over time. The influences of both the presence of psychosocial symptoms in general as well as novel psychosocial symptoms were analysed.

RESULTS

In total, 417 patients were included. Forty-nine patients [11.8%] experienced a flare during the study period. The occurrence of life events in the preceding 3 months was positively associated with flares (odds ratio [OR] = 1.81; 95% confidence interval [CI] = 1.04-3.17), while the presence of anxiety, depression, fatigue and perceived stress in general was not. However, novel perceived stress [OR = 2.92; 95% CI = 1.44-5.90] was associated with flares.

CONCLUSIONS

The occurrence of life events and novel perceived stress are associated with disease flares in the next 3 months, while the presence of perceived stress in general is not. These findings underline the importance of continuous personalized monitoring of IBD patients and may contribute to the prevention of disease flares.

Neuroimmunophysiology of the gut: advances and emerging concepts focusing on the epithelium

The epithelial lining of the gastrointestinal tract serves as the interface for digestion and absorption of nutrients and water and as a defensive barrier. The defensive functions of the intestinal epithelium are remarkable considering that the gut lumen is home to trillions of resident bacteria, fungi and protozoa (collectively, the intestinal microbiota) that must be prevented from translocation across the epithelial barrier. Imbalances in the relationship between the intestinal microbiota and the host lead to the manifestation of diseases that range from disorders of motility and sensation (IBS) and intestinal inflammation (IBD) to behavioural and metabolic disorders, including autism and obesity. The latest discoveries shed light on the sophisticated intracellular, intercellular and interkingdom signalling mechanisms of host defence that involve epithelial and enteroendocrine cells, the enteric nervous system and the immune system. Together, they maintain homeostasis by integrating luminal signals, including those derived from the microbiota, to regulate the physiology of the gastrointestinal tract in health and disease. Therapeutic strategies are being developed that target these signalling systems to improve the resilience of the gut and treat the symptoms of gastrointestinal disease.

Etiology, pathogenesis, diagnosis and treatment of bile reflux gastritis

Bile reflux gastritis is a common disease of the digestive system, whose clinical characteristics are abdominal pain, abdominal distention and nausea and vomiting, affecting the quality of life of patients seriously. However, the etiology and pathogenesis of bile reflux gastritis are still unclear, which may be related to gastrointestinal surgery, gallbladder disease, Helicobacter pylori infection, psychological factors, etc. There are many diagnostic methods, but a consensus on diagnosis is still lacking. Most of the current treatments are symptomatic treatments, but the overall efficacy is poor. This article reviews the etiology, pathogenesis, diagnosis and treatment of bile reflux gastritis, with an aim to provide a reference for further research of this disease.

GABAA Receptor Subtypes Regulate Stress-Induced Colon Inflammation in Mice

BACKGROUND & AIMS

Psychological stress, in early life or adulthood, is a significant risk factor for inflammatory disorders, including inflammatory bowel diseases. However, little is known about the mechanisms by which emotional factors affect the immune system. γ-Aminobutyric acid type A receptors (GABA_ARs) regulate stress and inflammation, but it is not clear whether specific subtypes of GABA_ARs mediate stress-induced gastrointestinal inflammation. We investigated the roles of different GABA_AR subtypes in mouse colon inflammation induced by 2 different forms of psychological stress.

METHODS

C57BL/6J mice were exposed to early-life stress, and adult mice were exposed to acute-restraint stress; control mice were not exposed to either form of stress. We collected colon tissues and measured contractility using isometric tension recordings; colon inflammation, based on levels of cluster of differentiation 163 and tumor necrosis factor messenger RNA (mRNA) and protein and myeloperoxidase activity; and permeability, based on levels of tight junction protein 1 and occludin mRNA and protein. Mice were given fluorescently labeled dextran orally and systemic absorption was measured. We also performed studies of mice with disruption of the GABA_AR subunit α3 gene (Gabra3^-/- mice).

RESULTS

Mice exposed to early-life stress had significantly altered GABA_AR-mediated colonic contractility and impaired barrier function, and their colon tissue had increased levels of Gabra3 mRNA compared with control mice. Restraint stress led to colon inflammation in C57/BL6J mice but not Gabra3^-/- mice. Colonic inflammation was induced in vitro by an α3-GABA_AR agonist, showing a proinflammatory role for this receptor subtype. In contrast, α1/4/5-GABA_AR ligands decreased the expression of colonic inflammatory markers.

CONCLUSIONS

We found stress to increase expression of Gabra3 and induce inflammation in mouse colon, together with impaired barrier function. The in vitro pharmacologic activation of α3-GABA_ARs recapitulated colonic inflammation, whereas α1/4/5-GABA_AR ligands were anti-inflammatory. These proteins might serve as therapeutic targets for treatment of colon inflammation or inflammatory bowel diseases.

The stress concept in gastroenterology: from Selye to today

More than eighty years after Hans Selye (1907-1982) first developed a concept describing how different types of environmental stressors affect physiological functions and promote disease development (called the "general adaptation syndrome") in 1936, we herein review advances in theoretical, mechanistic, and clinical knowledge in stress research, especially in the area of gastroenterology, and summarize progress and future perspectives arising from an interdisciplinary psychoneurobiological framework in which genetics, epigenetics, and other advanced ( omics) technologies in the last decade continue to refine knowledge about how stress affects the brain-gut axis in health and gastrointestinal disease. We demonstrate that neurobiological stress research continues to be a driving force for scientific progress in gastroenterology and related clinical areas, inspiring translational research from animal models to clinical applications, while highlighting some areas that remain incompletely understood, such as the roles of sex/gender and gut microbiota in health and disease. Future directions of research should include not only the genetics of the stress response and resilience but also epigenetic contributions.

Intrinsic neural network dysfunction in quiescent Crohn's Disease

Psychological factors and comorbidities play an important role in inflammatory bowel diseases. Such comorbidity could be associated with a specific neural phenotype. Brain regions associated with emotion regulation and self-referential processing, including areas assigned to the “default mode network” (DMN), could be promising candidates in this regard. We investigated the functional integrity of multiple intrinsic neural networks in remitted patients with Crohn’s disease (CD) and sought to establish relationships between neural network connectivity and psychiatric symptoms. Fifteen CD patients in remission and 14 controls were investigated. We employed resting-state functional magnetic resonance imaging (fMRI) at 3 Tesla followed by a spatial Independent Component Analysis for fMRI data. Abnormal connectivity in CD patients was observed in DMN subsystems only (p < 0.05, cluster-corrected). Increased connectivity was found in the anterior cingulate and left superior medial frontal gyrus (aDMN) and the middle cingulate cortex (pDMN). Middle cingulate activity showed a significant association with anxiety scores in patients (p = 0.029). This study provides first evidence of selectively disrupted intrinsic neural network connectivity in CD and suggests abnormalities of self-referential neural networks. An increased sensitivity to self-related affective and somatic states in CD patients could account for these findings and explain a higher risk for anxiety symptoms.