Regional Gray Matter Volume Changes in Brains of Patients With Ulcerative Colitis

Vascular Disease Is Associated With Differences in Brain Structure and Lower Cognitive Functioning in Inflammatory Bowel Disease: A Cross-Sectional Study

BACKGROUND

Vascular disease and cognitive impairment have been increasingly documented in inflammatory bowel disease (IBD), and both have been individually correlated with changes in brain structure. This study aimed to determine if both macro- and microstructural brain changes are prevalent in IBD and whether alterations in brain structure mediate the relationship between vascular disease and cognitive functioning.

METHODS

Eighty-four IBD participants underwent multimodal magnetic resonance imaging. Volumetric and mean diffusivity measures of the thalamus, hippocampus, normal-appearing white matter, and white matter lesions were converted to age- and sex-adjusted z scores. Vascular comorbidity was assessed using a modified Framingham Risk Score and cognition was assessed using a battery of neuropsychological tests. Test scores were standardized using local regression-based norms. We generated summary statistics for the magnetic resonance imaging metrics and cognitive tests, and these were examined using canonical correlation analysis and linear regression modeling.

RESULTS

Greater vascular comorbidity was negatively correlated with thalamic, normal-appearing white matter, and white matter lesion volumes. Higher Framingham Risk Score were also correlated with lower processing speed, learning and memory, and verbal fluency. Increased vascular comorbidity was predictive of poorer cognitive functioning, and this effect was almost entirely mediated (94.76%) by differences in brain structure.

CONCLUSIONS

Vascular comorbidity is associated with deleterious effects on brain structure and lower cognitive functioning in IBD. These findings suggest that proper identification and treatment of vascular disease is essential to the overall management of IBD, and that certain brain areas may serve as critical targets for predicting the response to therapeutic interventions.

Functional and Structural Abnormalities in the Pain Network of Generalized Anxiety Disorder Patients with Pain Symptoms

Pain symptoms significantly impact the well-being and work capacity of individuals with generalized anxiety disorder (GAD), and hinder treatment and recovery. Despite existing literature focusing on the neural substrate of pain and anxiety separately, further exploration is needed to understand the possible neuroimaging mechanisms of the pain symptoms in GAD patients. We recruited 73 GAD patients and 75 matched healthy controls (HC) for clinical assessments, as well as resting-state functional and structural magnetic resonance imaging scans. We defined a pain-related network through a published meta-analysis, including the insula, thalamus, periaqueductal gray, prefrontal cortex, anterior cingulate cortex, amygdala, and hippocampus. Subsequently, we conducted the regional homogeneity (ReHo) and the gray matter volume (GMV) within the pain-related network. Correlation analysis was then employed to explore associations between abnormal regions and self-reported outcomes, assessed using the Patient Health Questionnaire-15 (PHQ-15) and pain scores. We observed significantly increased ReHo in the bilateral insula but decreased GMV in the bilateral thalamus of GAD compared to HC. Further correlation analysis revealed a positive correlation between ReHo of the left anterior insula and pain scores in GAD patients, while a respective negative correlation between GMV of the bilateral thalamus and PHQ-15 scores. In summary, GAD patients exhibit structural and functional abnormalities in pain-related networks. The enhanced ReHo in the left anterior insula is correlated with pain symptoms, which might be a crucial brain region of pain symptoms in GAD.

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.

Brain imaging derived phenotypes: a biomarker for the onset of inflammatory bowel disease and a potential mediator of mental complications

Background and aims

Inflammatory bowel disease (IBD), mainly categorized into Crohn's disease (CD) and ulcerative colitis (UC), is a chronic relapsing gastrointestinal disorder that significantly impairs patients' quality of life. IBD patients often experience comorbidities such as anxiety and depression, and the underlying mechanisms and treatment strategies remain areas of investigation.

Methods

We conducted a Mendelian randomization(MR) analysis utilizing brain image derived phenotypes (IDP) from the UK Biobank database to investigate the causal relationships between IBD and alterations in brain structural morphology and connectivity of neural tracts. This study aimed to identify biological evidence linking IBD to psychiatric disorders such as anxiety and depression.

Results

Specifically, the volume of grey matter in the Left Frontal Orbital Cortex exhibited a negative association with the onset of Crohn's disease (odds ratio (OR) [95% confidence interval (CI)]: 0.315[0.180~0.551], adjusted P=0.001), while the volume of the superior frontal cortex in the right hemisphere showed a positive correlation with the development of Ulcerative colitis (OR [95% CI]: 2.285[1.793~2.911], adjusted P<0.001), and the volume of lateral occipital cortex in the left hemisphere demonstrated a positive relationship with Crohn's disease onset (OR [95% CI]: 1.709[1.671~1.747], adjusted P<0.001). In the context of reverse causality, the onset of UC or CD has led to alterations in imaging derived phenotypes associated with five disorders (anxiety, depression, schizophrenia, bipolar disorder, pain) and three functions (memory, emotion, language).

Conclusion

Our study has demonstrated a causal relationship between IBD and IDPs. IDPs may serve as potential biomarkers for the progression of IBD and as predictive intermediaries for the development of neurological diseases in IBD patients.

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.

Immunoception: the insular cortex perspective

To define the systemic neuroimmune interactions in health and disease, we recently suggested immunoception as a term that refers to the existence of bidirectional functional loops between the brain and the immune system. This concept suggests that the brain constantly monitors changes in immune activity and, in turn, can regulate the immune system to generate a physiologically synchronized response. Therefore, the brain has to represent information regarding the state of the immune system, which can occure in multiple ways. One such representation is an immunengram, a trace that is partially stored by neurons and partially by the local tissue. This review will discuss our current understanding of immunoception and immunengrams, focusing on their manifestation in a specific brain region, the insular cortex (IC).

Altered voxel-based and surface-based morphometry in inflammatory bowel disease

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is characterized by inflammation of the gastrointestinal tract and is a disorder of the brain-gut axis. Neuroimaging studies of brain function and structure have helped better understand the relationships between the brain, gut, and comorbidity in IBD. Studies of brain structure have primarily employed voxel-based morphometry to measure grey matter volume and surface-based morphometry to measure cortical thickness. Far fewer studies have employed other surface-based morphometry metrics such as gyrification, cortical complexity, and sulcal depth. In this study, brain structure differences between 72 adults with IBD and 90 healthy controls were assessed using all five metrics. Significant differences were found for cortical thickness with the IBD group showing extensive left-lateralized thinning, and for cortical complexity with the IBD group showing greater complexity in the left fusiform and right posterior cingulate. No significant differences were found in grey matter volume, gyrification, or sulcal depth. Within the IBD group, a post hoc analysis identified that disease duration is associated with cortical complexity of the right supramarginal gyrus, albeit with a more lenient threshold applied.

Causality between inflammatory bowel disease and the cerebral cortex: insights from Mendelian randomization and integrated bioinformatics analysis

Background

Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD), is a chronic, progressive, and recurrent intestinal condition that poses a significant global health burden. The high prevalence of neuropsychiatric comorbidities in IBD necessitates the development of targeted management strategies.

Methods

Leveraging genetic data from genome-wide association studies and Immunochip genotype analyses of nearly 150,000 individuals, we conducted a two-sample Mendelian randomization study to elucidate the driving force of IBD, UC, and CD on cortical reshaping. Genetic variants mediating the causality were collected to disclose the biological pathways linking intestinal inflammation to brain dysfunction.

Results

Here, 115, 69, and 98 instrumental variables genetically predicted IBD, UC, and CD. We found that CD significantly decreased the surface area of the temporal pole gyrus (β = -0.946 mm2, P = 0.005, false discovery rate-P = 0.085). Additionally, we identified suggestive variations in cortical surface area and thickness induced by exposure across eight functional gyri. The top 10 variant-matched genes were STAT3, FOS, NFKB1, JAK2, STAT4, TYK2, SMAD3, IL12B, MYC, and CCL2, which are interconnected in the interaction network and play a role in inflammatory and immune processes.

Conclusion

We explore the causality between intestinal inflammation and altered cortical morphology. It is likely that neuroinflammation-induced damage, impaired neurological function, and persistent nociceptive input lead to morphological changes in the cerebral cortex, which may trigger neuropsychiatric disorders.

Disruption of Periaqueductal Gray-default Mode Network Functional Connectivity in Patients with Crohn's Disease with Abdominal Pain

Abdominal pain in Crohn's disease (CD) has been known to be associated with changes in the central nervous system. The periaqueductal gray (PAG) plays a well-established role in pain processing. However, the role of PAG-related network and the effect of pain on the network in CD remain unclear.Resting-state functional magnetic imaging (fMRI) data were collected from 24 CD patients in remission with abdominal pain, 24 CD patients without abdominal pain and 28 healthy controls (HCs). Using the subregions of PAG (dorsomedial (dmPAG), dorsolateral (dlPAG), lateral (lPAG) and ventrolateral (vlPAG)) as seeds, the seed-based FC maps were calculated and one-way analysis of variance (ANOVA) was performed to investigate the differences among the three groups.Results showed that the group differences were mainly involved in the FC of the vlPAG with the precuneus, medial prefrontal cortex (mPFC) as well as orbitofrontal cortex (OFC), and the FC of the right lateral PAG (lPAG) with the precuneus, inferior parietal lobule (IPL), angular gyrus and premotor cortex. The FC values of all these regions decreased successively in the order of HCs, CD without abdominal pain and CD with abdominal pain. The pain score was negatively correlated with the FC of the l/vlPAG with the precuneus, angular gyrus and mPFC in CD patients with abdominal pain.This study implicated the disrupt communication between the PAG and the default mode network (DMN). These findings complemented neuroimaging evidence for the pathophysiology of visceral pain in CD patients.

A meta-analysis of structural MRI studies of the brain in systemic lupus erythematosus (SLE)

A comprehensive search of published literature in brain volumetry was conducted in three autoimmune diseases - systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and ulcerative colitis (UC) - with the intention of performing a meta-analysis of published data. Due to the lack of data in RA and UC, the reported meta-analysis was limited to SLE. The MEDLINE database was searched for studies from 1988 to March 2022. A total of 175 papers met the initial inclusion criteria, and 16 were included in a random-effects meta-analysis. The reduction in the number of papers included in the final analysis is primarily due to the lack of overlap in measured and reported brain regions. A significantly lower volume was seen in patients with SLE in the hippocampus, corpus callosum, and total gray matter volume measurements as compared to age- and sex-matched controls. There were not enough studies to perform a meta-analysis for RA and UC; instead, we include a summary of published volumetric studies. The meta-analyses revealed structural brain abnormalities in patients with SLE, suggesting that lower global brain volumes are associated with disease status. This volumetric difference was seen in both the hippocampus and corpus callosum and total gray matter volume measurements. These results indicate both gray and white matter involvements in SLE and suggest there may be both localized and global reductions in brain volume.

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.

Gray matter microstructural alterations in manganese-exposed welders: a preliminary neuroimaging study

OBJECTIVES

Chronic occupational manganese (Mn) exposure is characterized by motor and cognitive dysfunction. This study aimed to investigate structural abnormalities in Mn-exposed welders compared to healthy controls (HCs).

METHODS

Thirty-five HCs and forty Mn-exposed welders underwent magnetic resonance imaging (MRI) scans in this study. Based on T1-weighted MRI, the voxel-based morphometry (VBM), structural covariance, and receiver operating characteristic (ROC) curve were applied to examine whole-brain structural changes in Mn-exposed welders.

RESULTS

Compared to HCs, Mn-exposed welders had altered gray matter volume (GMV) mainly in the medial prefrontal cortex, lentiform nucleus, hippocampus, and parahippocampus. ROC analysis indicated the potential highest classification power of the hippocampus/parahippocampus. Moreover, distinct structural covariance patterns in the two groups were associated with regions, mainly including the thalamus, insula, amygdala, sensorimotor area, and middle temporal gyrus. No significant relationships were found between the findings and clinical characteristics.

CONCLUSIONS

Our findings showed Mn-exposed welders had changed GMV and structural covariance patterns in some regions, which implicated in motivative response, cognitive control, and emotional regulation. These results might provide preliminary evidence for understanding the pathophysiology of Mn overexposure.

KEY POINTS

• Chronic Mn exposure might be related to abnormal brain structural neural mechanisms. • Mn-exposed welders had morphological changes in brain regions implicated in emotional modulation, cognitive control, and motor-related response. • Altered gray matter volume in the hippocampus/parahippocampus and putamen might serve as potential biomarkers for Mn overexposure.