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

Inflammatory bowel disease and neuropsychiatric disorders: Mechanisms and emerging therapeutics targeting the microbiota-gut-brain axis

Crohn's disease (CD) and ulcerative colitis (UC) are the two major entities of inflammatory bowel disease (IBD). These disorders are known for their relapsing disease course and severe gastrointestinal symptoms including pain, diarrhoea and bloody stool. Accumulating evidence suggests that IBD is not only restricted to the gastrointestinal tract and that disease processes are able to reach distant organs including the brain. In fact, up to 35 % of IBD patients also suffer from neuropsychiatric disorders such as generalized anxiety disorder and major depressive disorder. Emerging research in this area indicates that in many cases these neuropsychiatric disorders are a secondary condition as a consequence of the disturbed communication between the gut and the brain via the microbiota-gut-brain axis. In this review, we summarise the current knowledge on IBD-associated neuropsychiatric disorders. We examine the role of different pathways of the microbiota-gut-brain axis in the development of CNS disorders highlighting altered neural, immunological, humoral and microbial communication. Finally, we discuss emerging therapies targeting the microbiota-gut-brain axis to alleviate IBD and neuropsychiatric symptoms including faecal microbiota transplantation, psychobiotics, microbial metabolites and vagus nerve stimulation.

A systematic review of digital and imaging technologies for measuring fatigue in immune mediated inflammatory diseases

Chronic fatigue greatly impacts the quality of life in individuals with immune-mediated inflammatory disease (IMID). Currently, fatigue assessment relies on patient-reported outcome (PRO) questionnaires. A systematic review following PRISMA guidelines was conducted to explore how digital and imaging technologies have been used to measure fatigue. PubMed and Cochrane Library were searched from 2003 to June 2023. Study quality was assessed using the STROBE checklist for observational studies. The database search identified 1541 studies; 16 were selected for inclusion, including three clinical trial reports. Disease cohorts included in this review were rheumatoid arthritis, primary Sjögren's syndrome, systemic lupus erythematosus, and inflammatory bowel disease. The majority of the studies found significant associations between fatigue, as assessed by PROs, and various digital and imaging endpoints. However, the studies were limited by a small sample size and short duration. This review stresses the need for additional research on fatigue using innovative digital and imaging modalities.

Deconditioning in quiescent Crohn's disease patients with heightened fatigue perception

BACKGROUND AND OBJECTIVE

Inflammatory bowel disease (IBD) fatigue aetiology is poorly understood. This study quantified body composition and physical function alongside proton magnetic resonance imaging (1H MRI) and spectroscopy (31P MRS) measures of organ structure and function in quiescent Crohn's disease patients (CD) and healthy volunteers (HVs), to identify a physiological basis for IBD fatigue.

METHODS

Body composition was determined using dual-energy X-ray absorptiometry and 1H MRI. Knee extensor isometric strength and isokinetic fatigue were measured using dynamometry. 1H MRI was used to quantify cardiac output, cerebral blood flow (gmCBF), and brain oxygen extraction fraction (OEF) at rest, and during supine, steady-state exercise, and recovery. 31P MRS was used to quantify post-exercise muscle phosphocreatine (PCr) resynthesis.

RESULTS

Sixteen CD and 12 HV (age, sex, and BMI matched) were recruited. Fatigue perception was greater (13.9 ± 1 vs 8.3 ± 0.9, P = .001), and daily step count was less (5482 ± 684 vs 8168 ± 1123, P = .04) in CD. During steady-state exercise, gmCBF was less in CD (653 ± 30 vs 823 ± 40 mL/min, P = .003). Cardiac output and brain OEF were no different. Post-exercise PCr resynthesis was less in CD (17.2 ± 2.0 vs 25.3 ± 2.4 mM·min-1, P = .02). Body composition, isometric strength, and isokinetic fatigability were no different.

CONCLUSIONS

CD self-reported increased fatigue perception and exhibited a slower rate of post-exercise PCr resynthesis compared to HV. This occurred independently of changes in body composition, muscle strength, and fatigability. IBD fatigue may be linked to peripheral muscle deconditioning and lower gmCBF during submaximal exercise.

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.

Associations Between Brain Morphology, Inflammatory Markers, and Symptoms of Fatigue, Depression, or Anxiety in Active and Remitted Crohn's Disease

BACKGROUND

Fatigue and psychosocial impairments are highly prevalent in IBD, particularly during active disease. Disturbed brain-gut interactions may contribute to these symptoms. This study examined associations between brain structure, faecal calprotectin, and symptoms of fatigue, depression, and anxiety in persons with Crohn's disease [CD] in different disease states.

METHODS

In this prospective observational study, n = 109 participants [n = 67 persons with CD, n = 42 healthy controls] underwent cranial magnetic resonance imaging, provided stool samples for analysis of faecal calprotectin, and completed questionnaires to assess symptoms of fatigue, depression, and anxiety. We analysed differences in grey matter volume [GMV] between patients and controls, and associations between regional GMV alterations, neuropsychiatric symptoms, and faecal calprotectin.

RESULTS

Symptoms of fatigue, depression, and anxiety were increased in patients with CD compared with controls, with highest scores in active CD. Patients exhibited regionally reduced GMV in cortical and subcortical sensorimotor regions, occipitotemporal and medial frontal areas. Regional GMV differences showed a significant negative association with fatigue, but not with depression or anxiety. Subgroup analyses revealed symptom-GMV associations for fatigue in remitted but not in active CD, whereas fatigue was positively associated with faecal calprotectin in active but not in remitted disease.

CONCLUSION

Our findings support disturbed brain-gut interactions in CD which may be particularly relevant for fatigue during remitted disease. Reduced GMV in the precentral gyrus and other sensorimotor areas could reflect key contributions to fatigue pathophysiology in CD. A sensorimotor model of fatigue in CD could also pave the way for novel treatment approaches.

Evidence linking gut-brain axis and Crohn's disease, focusing on neurotrophic dysfunctions and radiological imaging analysis - a systematic review

OBJECTIVE

To conduct a systematic review (SR) to find evidence for a connection between Crohn's disease (CD) and the gut-brain axis (GBA).

METHODS

This study conducted a systematic review (SR) employing a search strategy and strict inclusion criteria. It was conducted by searching for studies published between 2017 and 2024 in the following databases: PUBMED, PUBMED PMC, BVS-BIREME, SCOPUS, WEB OF SCIENCE, EMBASE, and COCHRANE.

RESULTS

Fifty original research articles were included. Among these, 20 studies addressed neuroimaging methods to evaluate CD patients' functional or structural brain changes. Neurodegenerative diseases were the second most addressed topic in the studies, with 18 articles related to different diseases such as Parkinson's disease, Alzheimer's disease, dementia, Amyotrophic Lateral Sclerosis, Multiple Sclerosis, and Multiple System Atrophy. Eight articles addressed sleep disorders related to CD; two explored Electroencephalography changes; one investigated Brain-Derived Neurotrophic Factor serum levels and one correlated vagotomy with CD.

CONCLUSION

Interest in the link between CD and GBA is increasing, but studies remain varied and inconclusive, spanning from epidemiology to brain imaging and neglecting to investigate a mechanistic relationship. This SR underscores the need for further research to better understand the potential role of GBA in the prognosis and etiology of CD, highlighting its complexity.

Structural alterations of brain in different disease states of Crohn's disease: Results of a cross-sectional study in a Chinese hospital

Rationale and objectives

To investigate alterations in the brain structure in patients with Crohn's disease in activity (CD-A) and in remission (CD-R) compared to healthy controls (HCs) and explore the relationship between gray matter volume (GMV) and psychological disorders.

Materials and methods

A total of 127 CD patients (62 CD-A, 65 CD-R) and 92 healthy controls (HCs) were enrolled and analyzed in this study. The Crohn's disease activity index (CDAI) was used as the grouping criteria. Voxel-based morphometry (VBM) was applied to investigate gray matter volume (GMV), white matter volume (WMV) and global cerebrospinal fluid (CSF) volume alterations. Pearson correlation analysis was used to evaluate the relationships.

Results

The CSF volume was negatively correlated with the disease duration in CD-R. Increased GMV of CD was observed in the parahippocampal gyrus, precentral gyrus, precuneous cortex, and subcallosal cortex, decreased was located in the occipital pole, precentral gyrus, inferior temporal gyrus, middle frontal gyrus, angular gyrus, frontal pole, lateral occipital cortex, and lingual gyrus. The GMV in the right temporal pole, left precuneous cortex, and left cingulate gyrus had a positive correlation with erythrocyte and hemoglobin in CD groups. The GMV in the right frontal pole, right postcentral gyrus, and left cingulate gyrus had a negative correlation with somatization in the CD groups. The GMV in the right temporal pole had a negative correlation with psychoticism and other in the CD groups. The GMV in the left cingulate gyrus was positive with bowel symptoms and systemic symptoms in the CD groups.

Conclusion

Alterations of GMV in CD-A and CD-R and associated correlation with psychological disorders may provide evidence for possible neuro-mechanisms of CD with psychological disorders.

Structural brain morphometry differences and similarities between young patients with Crohn's disease in remission and healthy young and old controls

Introduction

Crohn's disease (CD), one of the main phenotypes of inflammatory bowel disease (IBD), can affect any part of the gastrointestinal tract. It can impact the function of gastrointestinal secretions, as well as increasing the intestinal permeability leading to an aberrant immunological response and subsequent intestinal inflammation. Studies have reported anatomical and functional brain changes in Crohn's Disease patients (CDs), possibly due to increased inflammatory markers and microglial cells that play key roles in communicating between the brain, gut, and systemic immune system. To date, no studies have demonstrated similarities between morphological brain changes seen in IBD and brain morphometry observed in older healthy controls..

Methods

For the present study, twelve young CDs in remission (M = 26.08 years, SD = 4.9 years, 7 male) were recruited from an IBD Clinic. Data from 12 young age-matched healthy controls (HCs) (24.5 years, SD = 3.6 years, 8 male) and 12 older HCs (59 years, SD = 8 years, 8 male), previously collected for a different study under a similar MR protocol, were analyzed as controls. T1 weighted images and structural image processing techniques were used to extract surface-based brain measures, to test our hypothesis that young CDs have different brain surface morphometry than their age-matched young HCs and furthermore, appear more similar to older HCs. The phonemic verbal fluency (VF) task (the Controlled Oral Word Association Test, COWAT) (Benton, 1976) was administered to test verbal cognitive ability and executive control.

Results/Discussion

On the whole, CDs had more brain regions with differences in brain morphometry measures when compared to the young HCs as compared to the old HCs, suggesting that CD has an effect on the brain that makes it appear more similar to old HCs. Additionally, our study demonstrates this atypical brain morphometry is associated with function on a cognitive task. These results suggest that even younger CDs may be showing some evidence of structural brain changes that demonstrate increased resemblance to older HC brains rather than their similarly aged healthy counterparts.

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.