The influence of the brain-gut axis in inflammatory bowel disease and possible implications for treatment

Expression and role of CTHRC1 in inflammatory bowel disease in children

Inflammatory bowel disease (IBD) is a chronic, progressive, immune-mediated, gastrointestinal inflammatory disease with increasing occurrences in children. Collagen triple helix repeat containing 1 (CTHRC1), a migration-promoting protein, acts as a tumor-promoting factor in malignant tumors. However, functions and mechanisms of CTHRC1 in children with IBD remain unclear. This study aimed to determine the effects and mechanisms of CTHRC1 on dextran sodium sulfate (DSS)-treated HT-29 cells. HT-29 control cells were exposed to 2% DSS to develop an in vitro IBD model. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to assess CTHRC1 expression in serum of children with IBD and HT-29 cells. Cell viability and apoptosis were assessed using MTT and flow cytometry (FCM). Expressions of cleaved-Caspase3 and Caspase3 were determined by western blotting. The cytokine production (TNF-α, IL-1β and IL-6) in HT-29 cells was measured by ELISA assay. Activation or inactivation of NF-κB signaling pathway was confirmed by western blot assay. Results showed that CTHRC1 expression was upregulated in the IBD serum and HT-29 control cells. The level of CTHRC1 was lower in CTHRC1-siRNA transfected cells than in control siRNA-treated cells. Notably, silence of CTHRC1 markedly enhanced HT-29 cells viability, decreased apoptotic cells, suppressed cleaved-Caspase3 expression, inhibited cleaved-Caspase3/Caspase3 ratio, reduced the production of inflammatory cytokines, and blocked NF-κB signaling pathway induced by DSS. However, these effects were reversed following diprovocim treatment. Thus, that knockdown of CTHRC1 alleviated DSS-induced HT-29 cell injury by inhibiting the NF-κB signaling pathway in vitro, providing a new therapeutic target for IBD in children.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-025-00705-x.

Mechanism of Wuling powder modulating proBDNF/p75NTR/sortilin and BDNF/TrkB pathways in the treatment of ulcerative colitis complicated with depression

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory disease affecting the colon. The most common psychological issue in UC patients is varying degrees of depression, which affects the condition and quality of life of UC patients and may lead to deterioration of the patient’s condition. UC drugs combined with antianxiety and antidepression drugs can alleviate symptoms of both depression and UC. Brain-derived neurotrophic factor (BDNF) precursor (proBDNF)/p75 neurotrophin receptor (p75NTR)/sortilin and BDNF/tropomyosin receptor kinase B (TrkB) signalling balance is essential for maintaining brain homeostasis and preventing the development of depressive behaviours.

AIM

To explore the mechanism by which Wuling powder regulates the proBDNF/p75NTR/sortilin and BDNF/TrkB pathways in the treatment of UC with depression.

METHODS

Depression was established in C57BL/6J mice via chronic restraint stress, and the UC model was induced with dextran sodium sulfate (DSS). In the treatment stage, mesalazine (MS) was the basic treatment, Wuling powder was the experimental treatment, and fluoxetine was the positive control drug for treating depression. Changes in intestinal mucosal inflammation, behaviour, and the proBDNFp75NTR/sortilin and BDNF/TrkB pathways were evaluated.

RESULTS

In the depression groups, Wuling powder decreased the immobility time, increased the distance travelled in the central zone and the total distance travelled, and restored balance in the proBDNF/p75NTR/sortilin and BDNF/TrkB signalling pathways. In the DSS and chronic restraint stress + DSS groups, immobility time increased, distance travelled in the central zone and total distance travelled decreased, activity of the proBDNF/p75NTR/sortilin pathway was upregulated, and activity of the BDNF/TrkB pathway was downregulated, indicating that mice with UC often have comorbid depression. Compared with those of MS alone, Wuling powder combined with MS further decreased the colon histopathological scores and the expression levels of tumor necrosis factor-alpha and interleukin-6 mRNAs.

CONCLUSION

This study confirmed that Wuling powder may play an antidepressant role by regulating the balance of the proBDNF/p75NTR/sortilin and BDNF/TrkB signalling pathways and further relieve intestinal inflammation in UC.

Do the hormetic effects of chlorogenic acid mediate some of the beneficial effects of coffee?

The present paper provides the first documentation and assessment of the capacity of chlorogenic acid to induce hormetic dose-response relationships. The findings suggest that chlorogenic acid may induce anabolic (i.e., growth) and catabolic (i.e., protective) hormetic dose responses in several cell types via a range of complementary and cross-talking pathways, affecting a spectrum of endpoints of biomedical and therapeutic importance. This paper also addresses the issue of whether the widely recognized beneficial effects of coffee consumption, as reported in multiple epidemiological studies, may be related to the hormetic effects of chlorogenic acid and its metabolites and their interactions. The present analysis suggests that some beneficial effects of coffee consumption may be due to the effects of chlorogenic acid and/or its metabolites on the gastrointestinal tract via their capacity to impact gastrointestinal integrity, structure, and functionality. These effects collectively contribute to the attenuation of the gastrointestinal tract and concurrent systemic oxidative stress, positively affecting a range of organ-specific effects.

Recent advances in clinical practice: mastering the challenge-managing IBS symptoms in IBD

Many patients with IBD report persisting symptoms, despite resolution of the inflammatory process. Although by definition, a diagnosis of IBS cannot be made, the prevalence of 'IBS in IBD' surpasses the rate of IBS in the global population by fivefold. Because IBS-like symptoms are associated with a decreased quality of life and increased healthcare utilisation in IBD, diagnosis and treatment are necessary. In this review, we summarise the current knowledge on IBS-like symptoms in IBD. A pathophysiological common ground is present, which includes genetic susceptibility, environmental triggers, gut microbial dysbiosis, increased intestinal permeability, visceral hypersensitivity and involvement of brain-gut interaction. When symptoms persist after resolution of inflammation, other GI diseases should be excluded based on the chief complaint, considering any possible psychological co-morbidity early in the diagnostic work-up. Subsequent treatment should be initiated that is evidence-based and often multimodal, including classical and non-classical pharmacological agents as well as lifestyle and microbiota-based approaches, spanning the breadth of the gut, brain and its interaction. Treatment goals in this substantial part of the IBD population should be adapted to not only focus on treating the inflammation but taking care of the patient.

Wearable technology in inflammatory bowel disease: current state and future direction

INTRODUCTION

Wearables are electronic devices worn on the body to collect health data. These devices, like smartwatches and patches, use sensors to gather information on various health parameters. This review highlights the current use and the potential benefit of wearable technology in patients with inflammatory bowel disease (IBD).

AREAS COVERED

In this review, we explore the current use of wearable technology in healthcare and the studies applying this technology in patients with IBD. We also discuss the limitations of using digital health data in general and wearable technology in particular in the current clinical paradigm and predict a path forward in how to rationally and effectively apply this technology to improve the care of patients with IBD. A comprehensive search of all suitable studies was conducted using the databases of PubMed, MEDLINE, Embase, and Scopus from inception to August 2024.

EXPERT OPINION

Currently, wearable technology is applied to the monitoring of IBD and prediction of flares using devices and sensors. Future applications include early disease detection using biosensors, advanced data collection through ingestible devices, gut microbiome monitoring, and integration with machine learning. These advancements promise to revolutionize disease management, including IBD, by enabling early diagnosis, personalized treatment, and improved patient outcomes.

Disease-State Dependent Associations Between Intrinsic Brain Function and Symptoms of Fatigue, Depression, and Anxiety in Crohn's Disease

BACKGROUND

Extraintestinal symptoms (EIS) in inflammatory bowel diseases, including fatigue, depression and anxiety, are highly prevalent, but poorly understood. Alterations of brain function may contribute to EIS, but their association with disease activity is unclear. This study analyzed intrinsic neural activity (INA) of individuals with Crohn's disease (CD) in different disease states and examined the relationship between INA and EIS.

METHODS

Patients with CD (n = 92) and healthy controls (n = 41) underwent functional magnetic resonance brain imaging and completed symptom-specific psychometry. Temporal (amplitude of low-frequency fluctuations, ALFF) and spatial (regional homogeneity, ReHo) markers of INA were compared between CD and controls and between active (patients with active Crohn's disease [aCD]) versus remitted (rCD) disease. Regression analyses explored disease-state-dependent associations between INA and EIS.

RESULTS

Patients exhibited aberrant INA in frontotemporal, occipital, and thalamic regions. Patients with aCD exhibited lower ALFF in left subcallosal cortex and inferior temporal gyri compared to rCD. Regional homogeneity in aCD was lower in left medial orbital gyrus and higher in right superior frontal, left inferior temporal, and left precentral gyrus. Compared to rCD, aCD showed higher ALFF predominantly in superior, ventro-, and dorsolateral prefrontal regions. Distinct associations between INA and EIS were detected in patients, particularly in the remitted state.

CONCLUSIONS

Intrinsic brain function in patients with CD varies by disease state, with prominent frontal cortex changes in active disease. These brain activity changes are at least partly related to the magnitude of neuropsychiatric symptoms and highlight a role of disturbed brain-gut interactions in the development of EIS especially in rCD.

Crohn's disease, irritable bowel syndrome, and chronic fatigue: the importance of communication and symptom management-a case report

BACKGROUND

Crohn's disease and irritable bowel syndrome may both cause abdominal pain and diarrhea. Irritable bowel syndrome not only is an important differential diagnosis for Crohn's disease but also occurs in one out of three patients with Crohn's disease in remission in parallel. If not adequately diagnosed and treated, additional functional symptoms such as fatigue and/or muscle pain may develop, indicating a more severe course.

CASE PRESENTATION

A 64-year-old Caucasian male with long-standing, widely inactive Crohn's disease presented with persistent diarrhea, bloating, abdominal pain, general fatigue, unexplained hip pain, and frequent shivering with cold extremities, which had worsened following a gastrointestinal infection and psychological stress. A plausible explanation of his symptoms, based on an understanding of mind-body interactions, the autonomic nervous system, and temperature regulation, combined with symptom relief, was associated with rapid and sustainable improvement. After 2.5 years of follow-up, the patient is almost symptom-free.

CONCLUSIONS

This case report exemplifies the interrelation between organic (Crohn's disease) and functional diseases (irritable bowel syndrome, chronic fatigue syndrome, and somatoform pain). It further demonstrates that these connections may be overlooked in daily practice and that providing a plausible explanation in combination with symptom relief may be important for patients with functional syndromes.

Assessment of the quality of life of patients with inflammatory bowel disease

INTRODUCTION

Ulcerative colitis (UC) and Crohn's disease (CD) are diseases that cause a significant impact on patients' quality of life. The aim of this study is to assess the impact of inflammatory bowel disease (IBD) on health-related quality of life (HRQoL).

MATERIAL AND METHODS

Observational, descriptive, cross-sectional study, carried out at Torrecárdenas Hospital (Almería). Patients over 14 years of age diagnosed with CD or UC were included. For the assessment of HRQoL, the reduced 9-item IBDQ-9 questionnaire was used.

RESULTS

106 patients with a mean age of 44 years were included, with a female predominance. Forty-five percent of the patients in the sample had UC compared to 55% with CD. Of the patients, 69.8% were in clinical remission. The median questionnaire score was 60.8 points out of 100. Statistically significant differences were observed between sexes, with worse HRQoL for females. No differences were observed between patients with UC and CD. Differences were also detected between patients who underwent surgery and those who did not. A negative association was observed between the number of flares and the questionnaire score.

CONCLUSIONS

In our study population, there is an acceptable HRQoL, with no differences observed between CD and UC. Female sex, absence of clinical remission, number of previous outbreaks, and surgery have a negative association with HRQoL.

Impact of Nursing Interventions via Telephone and Email on the Quality of Life of Patients with Inflammatory Bowel Disease: Preliminary Results of a Comparative Observational Study

BACKGROUND

Inflammatory bowel disease (IBD), encompassing ulcerative colitis and Crohn's disease, is a heterogeneous chronic condition characterized by periods of relapse and remission. Ulcerative colitis involves inflammation of the colon and rectum mucosa, while Crohn's disease causes deeper, transmural inflammation affecting all four gut layers from the mouth to the anus and can lead to complications such as fistulation. IBD significantly impacts patients' physical and psychological well-being, thus reducing their quality of life (QoL). We aimed to evaluate the effectiveness of nursing intervention facilitated through telephone and email support in improving the quality of life (QoL) of Inflammatory Bowel Disease (IBD) patients.

METHODS

A pilot comparative observational design with pre-test and post-test assessments was employed, involving 50 participants assigned to either an intervention group (Group A, n = 26) or a control group (Group B, n = 24). Group A received regular telephone consultations and prompt email responses from trained nurses; Group B received standard care. Data were collected at baseline and six months post-intervention (T1) using the Patient-Reported Outcomes Measurement Information System (PROMIS®) and Pittsburgh Sleep Quality Index.

RESULTS

Group A showed significant improvements in anxiety, depression, fatigue, and sleep quality, with p-values indicating the significance of these findings.

CONCLUSIONS

Tailored nursing support via remote communication significantly benefits IBD patients by alleviating psychological distress and enhancing their overall well-being, underscoring the importance of integrating such interventions into standard IBD care practices.

Chronic Abdominal Pain in Patients with Inflammatory Bowel Disease in Remission: A Continuing Challenge for Clinicians

Inflammatory bowel disease (IBD) is a chronic condition that includes ulcerative colitis and Crohn's disease. It is characterized by a relapsing and remitting pattern that negatively impacts quality of life (QoL). Current goals of treatment involve symptomatic, biochemical, and endoscopic remission in a treat-to-target approach. Despite effective treatment and remission of IBD, many patients report frequent and isolated abdominal pain. A wide range of etiologies exist, including surgery-related, infections, pelvic conditions, immune-related, and systemic illnesses. Disorders of the gut-brain interaction (DGBI), frequently characterized by abdominal pain, are increasingly recognized in IBD patients, including those with quiescent disease. Various mechanisms are involved and numerous non-pharmacologic and pharmacologic therapies have been proposed. Hereby, we outline the pertinent findings of the literature on management of chronic abdominal pain, focusing on quiescent IBD.

Cell-derived biomimetic drug delivery system for inflammatory bowel disease therapy

Inflammatory bowel disease (IBD) is a chronic recurrent disease with an increasing incidence year by year. At present, no safe and effective treatment for IBD exists. Thus, there is an urgent need to create new therapeutic options that have decreased adverse effects and positive clinical efficacy. A range of nanomaterials have fueled the advancement of nanomedicine in recent years, which is establishing more appealing and prospective treatment approaches for IBD. However, traditional synthetic nanomaterials still have some problems in the IBD drug delivery process, such as weak targeting ability of vectors, difficulty escaping immune surveillance, and poor biosecurity. Natural sources of biological nanomaterials have been identified to solve the above problems. A drug delivery system based on bionic technology is expected to achieve a new breakthrough in the targeted therapy of IBD by nanotechnology due to its organic integration of low immunogenicity and natural targeting of biological materials and the controllability and versatility of synthetic nanocarrier design. We begin this review by outlining the fundamental traits of both inflammatory and healthy intestinal microenvironments. Subsequently, we review the latest application of a cell-derived bionic drug delivery system in IBD therapy. Finally, we discuss the development prospects of this delivery system and challenges to its clinical translation. Biomimetic nanotherapy is believed to offer a new strategy for the treatment of IBD.

Specific probiotics and prebiotics to improve the quality of life of patients with chronic irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a chronic disorder with an important impact on patients' quality of life. Although several data indicate that psychological symptoms are frequently reported by patients with IBS, few therapies have been evaluated regarding these issues.

METHODS

A retrospective observational study was conducted to evaluate the effectiveness of a probiotic-based dietary supplement (Colicron®) in a group of patients with diarrhea-predominant IBS (IBS-D). We included patients treated with Colicron® (1 cps/day for 8 weeks). Primary endpoint was the gastrointestinal symptoms' remission evaluated by Visual Analogue Scale (VAS); secondary endpoint was the impact of the treatment on physical and mental health evaluated by Hospital Anxiety and Depression Score (HADS) and Short Form Health Survey 36 (SF-36). VAS was assessed at week 4 (T4), week 8 (T8) and week 12 (T12), whereas HADS and SF-36 were performed even at the start of the Colicron® treatment (T0).

RESULTS

An improvement of VAS Score was observed at T8 (P<0.001) and T12 (P<0.05) compared to T4. Lower HADS-A (anxiety subdomain) score was obtained at each time point versus T0 (P<0.01), and higher scores of all SF-36 domains were observed during the treatment (0.05

CONCLUSIONS

Colicron® could be useful in improving both gastrointestinal and psychological symptoms in IBS-D patients. Further prospective clinical trials are needed to confirm these preliminary data.

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Key Words Collapse

MESH Headings

• Humans
• Irritable Bowel Syndrome/psychology
• Irritable Bowel Syndrome/therapy
• Irritable Bowel Syndrome/complications
• Quality of Life
• Probiotics/therapeutic use
• Female
• Male
• Retrospective Studies
• Adult
• Middle Aged
• Prebiotics
• Chronic Disease
• Treatment Outcome
• Anxiety/etiology
• Diarrhea
• Depression/etiology
• Dietary Supplements

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Grants Collapse

Affiliation(s)

Lorenzo Bertani Department of General Surgery and Gastroenterology, Tuscany North West ASL, Hospital of Pontedera, Pontedera, Pisa, Italy -
Linda Balestrini Laboratori Aliveda srl, Crespina Lorenzana, Pisa, Italy
Lucia Chico Laboratori Aliveda srl, Crespina Lorenzana, Pisa, Italy
Giulia Della Scala Laboratori Aliveda srl, Crespina Lorenzana, Pisa, Italy
Francesca Geri Department of General Surgery and Gastroenterology, Tuscany North West ASL, Hospital of Pontedera, Pontedera, Pisa, Italy
Alessandro Tornar Department of General Surgery and Gastroenterology, Tuscany North West ASL, Hospital of Pontedera, Pontedera, Pisa, Italy
Claudio Belcari Department of General Surgery and Gastroenterology, Tuscany North West ASL, Hospital of Pontedera, Pontedera, Pisa, Italy

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Identification of neural alterations in patients with Crohn's disease with a novel multiparametric brain MRI-based radiomics model

OBJECTIVES

Gut-brain axis dysfunction has emerged as a key contributor to the pathogenesis of Crohn's disease (CD). The elucidation of neural alterations may provide novel insights into its management. We aimed to develop a multiparameter brain MRI-based radiomics model (RM) for characterizing neural alterations in CD patients and to interpret these alterations using multiomics traits.

METHODS

This prospective study enrolled 230 CD patients and 46 healthy controls (HCs). Participants voluntarily underwent brain MRI and psychological assessment (n = 155), blood metabolomics analysis (n = 260), and/or fecal 16S rRNA sequencing (n = 182). The RM was developed using 13 features selected from 13,870 first-order features extracted from multiparameter brain MRI in training cohort (CD, n = 75; HCs, n = 32) and validated in test cohort (CD, n = 34; HCs, n = 14). Multiomics data (including gut microbiomics, blood metabolomics, and brain radiomics) were compared between CD patients and HCs.

RESULTS

In the training cohort, area under the receiver operating characteristic curve (AUC) of RM for distinguishing CD patients from HCs was 0.991 (95% confidence interval (CI), 0.975-1.000). In test cohort, RM showed an AUC of 0.956 (95% CI, 0.881-1.000). CD-enriched blood metabolites such as triacylglycerol (TAG) exhibited significant correlations with both brain features detected by RM and CD-enriched microbiota (e.g., Veillonella). One notable correlation was found between Veillonella and Ctx-Lh-Middle-Temporal-CBF-p90 (r = 0.41). Mediation analysis further revealed that dysbiosis, such as of Veillonella, may regulate the blood flow in the middle temporal cortex through TAG.

CONCLUSION

We developed a multiparameter MRI-based RM that characterized the neural alterations of CD patients, and multiomics data offer potential evidence to support the validity of our model. Our study may offer clues to help provide potential therapeutic targets.

CRITICAL RELEVANCE STATEMENT

Our brain-gut axis study developed a novel model using multiparameter MRI and radiomics to characterize brain changes in patients with Crohn's disease. We validated this model's effectiveness using multiomics data, making it a potential biomarker for better patient management.

KEY POINTS

Utilizing multiparametric MRI and radiomics techniques could unveil Crohn's disease's neurophenotype. The neurophenotype radiomics model is interpreted using multiomics data. This model may serve as a novel biomarker for Crohn's disease management.

A vagus nerve dominant tetra-synaptic ascending pathway for gastric pain processing

Gastric pain has limited treatment options and the mechanisms within the central circuitry remain largely unclear. This study investigates the central circuitry in gastric pain induced by noxious gastric distension (GD) in mice. Here, we identified that the nucleus tractus solitarius (NTS) serves as the first-level center of gastric pain, primarily via the vagus nerve. The prelimbic cortex (PL) is engaged in the perception of gastric pain. The lateral parabrachial nucleus (LPB) and the paraventricular thalamic nucleus (PVT) are crucial regions for synaptic transmission from the NTS to the PL. The glutamatergic tetra-synaptic NTS-LPB-PVT-PL circuitry is necessary and sufficient for the processing of gastric pain. Overall, our finding reveals a glutamatergic tetra-synaptic NTS-LPB-PVT-PL circuitry that transmits gastric nociceptive signaling by the vagus nerve in mice. It provides an insight into the gastric pain ascending pathway and offers potential therapeutic targets for relieving visceral pain.

Underneath the Gut-Brain Axis in IBD-Evidence of the Non-Obvious

The gut-brain axis (GBA) plays a pivotal role in human health and wellness by orchestrating complex bidirectional regulation and influencing numerous critical processes within the body. Over the past decade, research has increasingly focused on the GBA in the context of inflammatory bowel disease (IBD). Beyond its well-documented effects on the GBA-enteric nervous system and vagus nerve dysregulation, and gut microbiota misbalance-IBD also leads to impairments in the metabolic and cellular functions: metabolic dysregulation, mitochondrial dysfunction, cationic transport, and cytoskeleton dysregulation. These systemic effects are currently underexplored in relation to the GBA; however, they are crucial for the nervous system cells' functioning. This review summarizes the studies on the particular mechanisms of metabolic dysregulation, mitochondrial dysfunction, cationic transport, and cytoskeleton impairments in IBD. Understanding the involvement of these processes in the GBA may help find new therapeutic targets and develop systemic approaches to improve the quality of life in IBD patients.

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.

Disease-specific alterations in central fear network engagement during acquisition and extinction of conditioned interoceptive fear in inflammatory bowel disease

Interoceptive fear, which is shaped by associative threat learning and memory processes, plays a central role in abnormal interoception and psychiatric comorbidity in conditions of the gut-brain axis. Although animal and human studies support that acute inflammation induces brain alterations in the central fear network, mechanistic knowledge in patients with chronic inflammatory conditions remains sparse. We implemented a translational fear conditioning paradigm to elucidate central fear network reactivity in patients with quiescent inflammatory bowel disease (IBD), compared to patients with irritable bowel syndrome (IBS) and healthy controls (HC). Using functional magnetic resonance imaging, conditioned differential neural responses within regions of the fear network were analyzed during acquisition and extinction learning. In contrast to HC and IBS, IBD patients demonstrated distinctly altered engagement of key regions of the central fear network, including amygdala and hippocampus, during differential interoceptive fear learning, with more pronounced responses to conditioned safety relative to pain-predictive cues. Aberrant hippocampal responses correlated with chronic stress exclusively in IBD. During extinction, differential engagement was observed in IBD compared to IBS patients within amygdala, ventral anterior insula, and thalamus. No group differences were found in changes of cue valence as a behavioral measure of fear acquisition and extinction. Together, the disease-specific alterations in neural responses during interoceptive fear conditioning in quiescent IBD suggest persisting effects of recurring intestinal inflammation on central fear network reactivity. Given the crucial role of interoceptive fear in abnormal interoception, these findings point towards inflammation-related brain alterations as one trajectory to bodily symptom chronicity and psychiatric comorbidity. Patients with inflammatory conditions of the gut-brain axis may benefit from tailored treatment approaches targeting maladaptive interoceptive fear.

Review article: Measuring disease severity in inflammatory bowel disease - Beyond treat to target

BACKGROUND

Inflammatory bowel disease (IBD) follows a heterogenous disease course and predicting a patient's prognosis is challenging. There is a wide burden of illness in IBD and existing tools measure disease activity at a snapshot in time. Comprehensive assessment of IBD severity should incorporate disease activity, prognosis, and the impacts of disease on a patient. This review investigates the concept of disease severity in adults with IBD to highlight key components contributing to this.

METHODS

To perform this narrative review, a Medline search was conducted for full-text articles available at 1st March 2024 using search terms which encompassed disease activity assessment, disease severity, prognosis, natural history of Crohn's disease (CD) and ulcerative colitis (UC), and the burden of IBD.

RESULTS

Current methods of disease assessment in IBD have evolved from a focus on the burden of symptoms to one that includes inflammatory targets, genetic, serological, and proteomic profiles, and assessments of quality-of-life (QoL), disability, and psychosocial health. Longitudinal studies of IBD suggest that the burden of illness is driven by disease phenotype, clinical markers of complicated disease course (previous intestinal resection, corticosteroid use, perianal disease in CD, recent hospitalisations in UC), gut inflammation, and the impact of IBD on the patient.

CONCLUSIONS

Disease severity in IBD can be difficult to conceptualise due to the multitude of factors that contribute to IBD outcomes. Measurement of IBD severity may better encapsulate the full burden of illness rather than gut inflammation alone at a single timepoint and may be associated with longitudinal outcomes.

Mixed-method Irish study exploring the role of diet in IBD based on an online questionnaire and a patient panel opinion

OBJECTIVE

Diet is a risk factor in inflammatory bowel diseases (IBD) pathogenesis. This study aims to examine the dietary patterns and beliefs of Irish patients living with IBD through an online questionnaire and subsequent open discussions with an IBD patient collaborator panel (PCP). All data presented here are selected and presented following the PCP's suggestions and views.

DESIGN

This mixed-method study included an online questionnaire using a short food frequency questionnaire examining dietary patterns, dietary opinions, beliefs and behaviours (phase I). Six in-person PCP sessions were conducted, where findings from the online questionnaire, diet and lifestyle in the context of IBD were discussed in depth (phase II).

RESULTS

The questionnaire revealed that respondents with active IBD are associated with the consumption of high-sugar, processed and meat-based foods while reducing their consumption of high-fibre foods. Individuals with active Crohn's disease have a decrease in overall daily energy consumption and a significant reduction in intake of fibre, non-starch polysaccharides, micronutrients [B vitamins (B1, B2, and B9), vitamin C, calcium] and trace elements (iron, zinc, copper and manganese). The PCP reported that food tolerability is limited during relapse, leading patients to prefer simple carbohydrates for energy, consistent with the dietary intake data. The PCP reported that most dietary advice was received during hospitalisation (relapse), focused on food avoidance, with little follow-up during remission. The consensus among the PCP was that factors, such as disease type, psychological aspects, dietary understanding and support, can influence peoples' dietary choices.

CONCLUSION

In summary, we show that dietary intake in people with IBD varies and may depend on several factors, not just the disease itself. This PCP desires more dietary information and professional support outside of hospitalisation to assist with disease management.

The potential influence of microplastics on the microbiome and disease susceptibility in sea turtles

Microplastics (MPs) are particles with sizes of ≤5 mm formed when plastic materials break down. These contaminants are often found in marine environments, making it easy for sea turtles to ingest them and for their microbiome to be exposed. MPs can disrupt microbiome balance, leading to dysbiosis and making organisms more susceptible to diseases. Owing to the significance of these processes, it is crucial to dedicate research to studying the metabolic and genetic analysis of the gut microbiome in sea turtles. The objective of this study was to describe the effects of exposure to MPs on the gut microbiome of sea turtles, based on current knowledge. This review also aimed to explore the potential link between MP exposure and disease susceptibility in these animals. We show that the metabolites produced by the gut microbiome, such as short-chain fatty acids (SCFAs), polyamines, and polysaccharide A, can regulate the expression of host genes. Regulation occurs through various mechanisms, including histone acetylation, DNA methylation, and the modulation of cytokine gene expression. These processes are essential for preserving the integrity of the gut mucosa and enhancing the functionality of immune cells. Exposure to MPs disrupts the gut microbiome and alters gene expression, leading to immune system disturbances in sea turtles. This vulnerability makes turtles more susceptible to opportunistic microorganisms such as chelonid alphaherpesvirus 5 (ChAHV5), which is linked to the development of fibropapillomatosis (FP). Additionally, targeted dietary interventions or the use of live microorganisms such as probiotics can help restore microbial biodiversity and recover lost metabolic pathways. The goal of these interventions is to restore the functionality of the immune system in sea turtles undergoing rehabilitation at specialized centers. The gut microbiome plays a crucial role in sea turtle health, sparking discussions and investigations that can potentially lead to promising treatments for these animals.

Impact of Opioid Use on the Natural History of Inflammatory Bowel Disease: Prospective Longitudinal Follow-up Study

BACKGROUND

Opioid use is increasingly prevalent amongst patients with inflammatory bowel disease (IBD), but whether opioids have deleterious effects, or their use is merely linked with more severe disease, is unclear. We conducted a longitudinal follow-up study examining this issue.

METHODS

Data on demographics, gastrointestinal and psychological symptoms, quality of life, and opioid use were recorded at baseline. Data on healthcare use and adverse disease outcomes were obtained from a review of electronic medical records at 12 months. Characteristics at baseline of those using opioids and those who were not were compared, in addition to occurrence of flare, prescription of glucocorticosteroids, treatment escalation, hospitalization, or intestinal resection during the 12 months of follow-up.

RESULTS

Of 1029 eligible participants, 116 (11.3%) were taking opioids at baseline. Medium (odds ratio [OR], 4.67; 95% confidence interval [CI], 1.61-13.6) or high (OR, 8.03; 95% CI, 2.21-29.2) levels of somatoform symptom-reporting and use of antidepressants (OR, 2.54; 95% CI, 1.34-4.84) or glucocorticosteroids (OR, 6.63; 95% CI, 2.26-19.5; P < .01 for all analyses) were independently associated with opioid use. Following multivariate analysis, opioid users were significantly more likely to undergo intestinal resection (hazard ratio,  7.09; 95% CI, 1.63 to 30.9; P = .009), particularly when codeine or dihydrocodeine were excluded (hazard ratio, 42.9; 95% CI, 3.36 to 548; P = .004).

CONCLUSIONS

Opioid use in IBD is associated with psychological comorbidity and increased risk of intestinal resection, particularly in stronger formulations. Future studies should stratify the risk of individual opioids, so that robust prescribing algorithms can be developed and assess whether addressing psychological factors in routine IBD care could be an effective opioid avoidance strategy.

Allostatic load increases the incidence and risk of adverse prognosis in inflammatory bowel disease

BACKGROUND

Elevated allostatic load (AL) has been associated with the risk and poor prognosis of many chronic diseases. The association between AL and inflammatory bowel disease (IBD) is unknown.

AIMS

The aim of this study is to investigate the associations between AL and the risk and prognosis of IBD.

METHODS

We included 326,345 adults and 3767 patients with IBD from the UK Biobank. AL served as the exposure, estimated using the AL biomarker panel, with the primary outcomes including the risk and prognosis of IBD. We used Cox regression models to examine the associations.

RESULTS

High AL biomarker panel was associated with a greater risk of IBD (hazard ratio: 1.19, 95% CI: 1.08-1.31), ulcerative colitis (1.17, 95%CI: 1.04-1.32), and Crohn's disease (1.25, 95%CI: 1.05-1.49). Risk of developing IBD increased by 12% in quartile 2, 20% in quartile 3, and 37% in quartile 4 as AL biomarker panel increased. The all-cause mortality risk in IBD compared with quartile 1 rose by 54% for quartile 2, 72% for quartile 3, and 82% for quartile 4, as AL biomarker panel increased. Similar effects were also observed for ulcerative colitis and Crohn's disease. An increase in AL biomarker panel count was associated with an elevated risk of intestinal resection and colorectal cancer in IBD.

CONCLUSIONS

Increased AL is associated with IBD risk, as well as the risks of intestinal resection, colorectal cancer and mortality.

A population-based study of familial coaggregation and shared genetic etiology of psychiatric and gastrointestinal disorders

BACKGROUND

It has been proposed that having a psychiatric disorder could increase the risk of developing a gastrointestinal disorder, and vice versa. The role of familial coaggregation and shared genetic loading between psychiatric and gastrointestinal disorders remains unclear.

METHODS

This study used the Taiwan National Health Insurance Research Database; 4,504,612 individuals born 1970-1999 with parental information, 51,664 same-sex twins, and 3,322,959 persons with full-sibling(s) were enrolled. Genotyping was available for 106,796 unrelated participants from the Taiwan Biobank. A logistic regression model was used to examine the associations of individual history, affected relatives, and polygenic risk scores (PRS) for schizophrenia (SCZ), bipolar disorder (BPD), major depressive disorder (MDD), and obsessive-compulsive disorder (OCD), with the risk of peptic ulcer disease (PUD), gastroesophageal reflux disease (GERD), irritable bowel syndrome (IBS), and inflammatory bowel disease (IBD), and vice versa.

RESULTS

Here we show that parental psychiatric disorders are associated with gastrointestinal disorders. Full-siblings of psychiatric cases have an increased risk of gastrointestinal disorders except for SCZ/BPD and IBD; the magnitude of coaggregation is higher in same-sex twins than in full-siblings. The results of bidirectional analyses mostly remain unchanged. PRS for SCZ, MDD, and OCD are associated with IBS, PUD/GERD/IBS/IBD, and PUD/GERD/IBS, respectively. PRS for PUD, GERD, IBS, and IBD are associated with MDD, BPD/MDD, SCZ/BPD/MDD, and BPD, respectively.

CONCLUSIONS

There is familial coaggregation and shared genetic etiology between psychiatric and gastrointestinal comorbidity. Individuals with psychiatric disorder-affected relatives or with higher genetic risk for psychiatric disorders should be monitored for gastrointestinal disorders, and vice versa.

The communication mechanism of the gut-brain axis and its effect on central nervous system diseases: A systematic review

Gut microbiota is involved in intricate and active metabolic processes the host's brain function, especially its role in immune responses, secondary metabolism, and symbiotic connections with the host. Gut microbiota can promote the production of essential metabolites, neurotransmitters, and other neuroactive chemicals that affect the development and treatment of central nervous system diseases. This article introduces the relevant pathways and manners of the communication between the brain and gut, summarizes a comprehensive overview of the current research status of key gut microbiota metabolites that affect the functions of the nervous system, revealing those adverse factors that affect typical communication between the brain-gut axis, and outlining the efforts made by researchers to alleviate these neurological diseases through targeted microbial interventions. The relevant pathways and manners of communication between the brain and gut contribute to the experimental design of new treatment plans and drug development. The factors that may cause changes in gut microbiota and affect metabolites, as well as current intervention methods are summarized, which helps improve gut microbiota brain dialogue, prevent adverse triggering factors from interfering with the gut microbiota system, and minimize neuropathological changes.

Psychological Distress Is Associated With Inflammatory Bowel Disease Manifestation and Mucosal Inflammation

BACKGROUND

Stress is a potentially significant risk factor for the occurrence and progression of inflammatory bowel disease (IBD).

METHODS

The study analyzed the level of stress, anxiety, and depression in patients with Crohn's disease (CD; n = 50) and ulcerative colitis (UC; n = 54) in comparison with non-IBD controls (n = 100), using Perceived Stress Scale (PSS), Patient Health Questionnaire (PHQ-9), and Hospital Anxiety and Depression Scale (HADS) questionnaires. Additionally, a correlation between psychological scores and expression of IL17A, IL17F, and IL23A genes in the intestinal mucosa of IBD patients was assessed.

RESULTS

Compared to controls, CD and UC patients had higher PSS (P = 4 × 10-14, P = 2.5 × 10-16), PHQ-9 (P = 2 × 10-16, P = 2 × 10-16), HADS depression (P = 2.6 × 10-10, P = 2.5 × 10-11), and HADS anxiety (P = 3.5 × 10-9, P = 1.2 × 10-11). We found a positive correlation between PSS and IL17F mRNA (rs = 0.43, P = .036) while HADS depression and HADS anxiety positively correlated with the IL23A mRNA in inflamed ileal mucosa of CD subjects (rs = 0.55, P = .0048; rs = 0.53, P = .0062).

CONCLUSIONS

A significantly higher psychological distress was identified in IBD patients. CD patients with increased ileal expression of IL17F and IL23A genes had higher PSS and HADS, suggesting a potential interplay between psychological distress and inflammation.

Children and Young Adults With Inflammatory Bowel Disease Have an Increased Incidence and Risk of Developing Mental Health Conditions: A UK Population-Based Cohort Study

BACKGROUND

The burden of mental health conditions in children and young adults with inflammatory bowel disease remains unclear. We assessed this using a primary care database in the United Kingdom.

METHODS

A retrospective, observational study compared children and young adults with incident inflammatory bowel disease 5 to 25 years of age (2010-2020) against population control subjects. Outcomes comprised incident depression, anxiety disorder, eating disorders, body image disorders, attention-deficit disorders, behavioral disorders, adjustment disorders, acute stress disorder, schizophrenia, bipolar disorder, posttraumatic stress disorder, self-harm, parasuicide (including suicide), and sleep disturbance. The any mental health condition category comprised any of these conditions.

RESULTS

A total of 3898 young patients with incident inflammatory bowel disease were matched to 15 571 control subjects. Inflammatory bowel disease patients were significantly more likely to develop new posttraumatic stress disorder (adjusted hazard ratio [aHR], 2.47; 95% confidence interval [CI], 1.23-4.94), eating disorders (aHR, 1.85; 95% CI, 1.05-3.26), self-harm (aHR, 1.49; 95% CI, 1.00-2.21), sleep disturbance (aHR, 1.40; 95% CI, 1.15-1.71), depression (aHR, 1.34; 95% CI, 1.16- 1.56), anxiety (aHR, 1.25; 95% CI, 1.06-1.48), and any mental health condition (aHR, 1.28; 95% CI, 1.12-1.46). Male inflammatory bowel disease patients aged 12 to 17 years, and patients with Crohn's disease appear to have the highest risk for developing new mental health conditions.

CONCLUSIONS

Young inflammatory bowel disease patients have a significantly higher incidence and risk of new mental health conditions. Mental health remains a critically overlooked aspect of inflammatory bowel disease patient management. Further research into identifying optimal monitoring tools and support for these patients is required to improve patient care. The study protocol was specified and registered a priori.ClinicalTrials.gov study identifier: NCT05206734.

Miniaturized implantable temperature sensors for the long-term monitoring of chronic intestinal inflammation

Diagnosing and monitoring inflammatory bowel diseases, such as Crohn's disease, involves the use of endoscopic imaging, biopsies and serology. These infrequent tests cannot, however, identify sudden onsets and severe flare-ups to facilitate early intervention. Hence, about 70% of patients with Crohn's disease require surgical intestinal resections in their lifetime. Here we report wireless, miniaturized and implantable temperature sensors for the real-time chronic monitoring of disease progression, which we tested for nearly 4 months in a mouse model of Crohn's-disease-like ileitis. Local measurements of intestinal temperature via intraperitoneally implanted sensors held in place against abdominal muscular tissue via two sutures showed the development of ultradian rhythms at approximately 5 weeks before the visual emergence of inflammatory skip lesions. The ultradian rhythms showed correlations with variations in the concentrations of stress hormones and inflammatory cytokines in blood. Decreasing average temperatures over the span of approximately 23 weeks were accompanied by an increasing percentage of inflammatory species in ileal lesions. These miniaturized temperature sensors may aid the early treatment of inflammatory bowel diseases upon the detection of episodic flare-ups.

Systematic review and meta-analysis: Impact of depression on prognosis in inflammatory bowel disease

BACKGROUND AND AIM

Depression is highly prevalent in patients with inflammatory bowel disease (IBD), which may affect the prognosis of IBD. This aimed to investigate the impact of depression on prognosis in IBD.

METHODS

A systematic literature search was performed in four databases (Medline, Embase, Web of Science, and PsycINFO) up to December 31, 2023. Studies were included if they investigated the impact of depression on prognosis in IBD. The primary outcome was flare in IBD, and secondary outcomes were hospitalization, readmission, emergency visits, surgery, and escalation of medical therapy. Relative risks (RRs) were utilized to estimate the risk in each of the above prognostic indicators.

RESULTS

Fourteen cohort and 10 case-control studies matched our entry criteria, comprising 630 408 patients with IBD. Twenty-two of included studies were considered to have a low risk of bias. Depression was found to significantly increase the risk of flare (RR = 1.37, 95% CI 1.16-1.63), hospitalization (RR = 1.11, 95% CI 1.00-1.23), readmission (RR = 1.32, 95% CI 1.04-1.67), emergency visits (RR = 1.33, 95% CI 1.12-1.59), surgery (1.38, 95% CI 1.08-1.76), and escalation of medical therapy (RR = 1.38, 95% CI 1.13-1.69) in IBD. Of note, patients with depression in ulcerative colitis had significant differences in readmission (RR = 1.38, 95% CI 1.19-1.60) and escalation of medical therapy (RR = 1.78, 95% CI 1.55-2.04). Additionally, the association was observed in patients with Crohn's disease in terms of flare (RR = 1.47, 95% CI 1.08-2.01) and hospitalization (RR = 1.20, 95% CI 1.03-1.40).

CONCLUSIONS

Current evidence suggested that depression could significantly increase the risk of poor prognosis worsening in patients with IBD. However, the association varied in IBD subtypes.

Association between dietary inflammatory index and energy-adjusted dietary inflammatory index and constipation in US adults

BACKGROUND

Diet and inflammation are associated with constipation. Dietary inflammation index (DII) and energy-dietary inflammation index (E-DII) have not been evaluated together with constipation. Therefore, this study was conducted to further observe the relationship between DII and E-DII and constipation in American adults.

METHODS

Data were extracted from the National Health and Nutrition Examination Survey (NHANES) for 12,400 adults aged 20 years and older between 2005 and 2010. DII and E-DII were obtained by employing data from the two 24-h dietary recall of the participants. Constipation was defined and categorized using the Bristol Stool Form Scale.

RESULTS

In the logistic regression model, the relationship between DII and E-DII and constipation remained positive after adjusting for confounding factors (odds ratio [OR] = 1.13; 95% confidence interval [CI]: 1.07-1.20 in DII logistic regression model III; odds ratio [OR] = 1.09; 95% confidence interval [CI]: 1.03-1.17 in E-DII logistic regression model III). Constipation was more common in quartile 4 (DII: 2.87-5.09; E-DII: 1.78-8.95) than in quartile 1 (DII: -5.11-0.25; E-DII: -2.60-0.11) (OR = 1.79, 95% CI: 1.30-2.47 in DII and OR = 1.75, 95% CI: 1.25-2.46 in E-DII for all participants; OR = 2.04, 95% CI: 1.39-3.00 in DII OR = 2.20, 95% CI: 1.39-3.47 in E-DII for males; OR = 1.86, 95% CI: 1.08-3.22 and OR = 1.80, 95% CI: 1.06-3.06 for females). These results were confirmed using multiple imputations.

CONCLUSIONS

The findings of this study show that a high DII and E-DII were associated with an increased incidence of constipation among US adults.

Novel Insights into Changes in Gene Expression within the Hypothalamus in Two Asthma Mouse Models: A Transcriptomic Lung-Brain Axis Study

Patients with asthma experience elevated rates of mental illness. However, the molecular links underlying such lung-brain crosstalk remain ambiguous. Hypothalamic dysfunction is observed in many psychiatric disorders, particularly those with an inflammatory component due to many hypothalamic regions being unprotected by the blood-brain barrier. To gain a better insight into such neuropsychiatric sequelae, this study investigated gene expression differences in the hypothalamus following lung inflammation (asthma) induction in mice, using RNA transcriptome profiling. BALB/c mice were challenged with either bacterial lipopolysaccharide (LPS, E. coli) or ovalbumin (OVA) allergens or saline control (n = 7 per group), and lung inflammation was confirmed via histological examination of postmortem lung tissue. The majority of the hypothalamus was micro-dissected, and total RNA was extracted for sequencing. Differential expression analysis identified 31 statistically significant single genes (false discovery rate FDR5%) altered in expression following LPS exposure compared to controls; however, none were significantly changed following OVA treatment, suggesting a milder hypothalamic response. When gene sets were examined, 48 were upregulated and 8 were downregulated in both asthma groups relative to controls. REACTOME enrichment analysis suggests these gene sets are involved in signal transduction metabolism, immune response and neuroplasticity. Interestingly, we identified five altered gene sets directly associated with neurotransmitter signaling. Intriguingly, many of these altered gene sets can influence mental health and or/neuroinflammation in humans. These findings help characterize the links between asthma-induced lung inflammation and the brain and may assist in identifying relevant pathways and therapeutic targets for future intervention.

Alterations in tryptophan metabolism and de novo NAD+ biosynthesis within the microbiota-gut-brain axis in chronic intestinal inflammation

Background

Inflammatory bowel disease is an incurable and idiopathic disease characterized by recurrent gastrointestinal tract inflammation. Tryptophan metabolism in mammalian cells and some gut microbes comprise intricate chemical networks facilitated by catalytic enzymes that affect the downstream metabolic pathways of de novo nicotinamide adenine dinucleotide (NAD+) synthesis. It is hypothesized that a correlation exists between tryptophan de novo NAD+ synthesis and chronic intestinal inflammation.

Methods

Transcriptome analysis was performed using high-throughput sequencing of mRNA extracted from the distal colon and brain tissue of Winnie mice with spontaneous chronic colitis and C57BL/6 littermates. Metabolites were assessed using ultra-fast liquid chromatography to determine differences in concentrations of tryptophan metabolites. To evaluate the relative abundance of gut microbial genera involved in tryptophan and nicotinamide metabolism, we performed 16S rRNA gene amplicon sequencing of fecal samples from C57BL/6 and Winnie mice.

Results

Tryptophan and nicotinamide metabolism-associated gene expression was altered in distal colons and brains of Winnie mice with chronic intestinal inflammation. Changes in these metabolic pathways were reflected by increases in colon tryptophan metabolites and decreases in brain tryptophan metabolites in Winnie mice. Furthermore, dysbiosis of gut microbiota involved in tryptophan and nicotinamide metabolism was evident in fecal samples from Winnie mice. Our findings shed light on the physiological alterations in tryptophan metabolism, specifically, its diversion from the serotonergic pathway toward the kynurenine pathway and consequential effects on de novo NAD+ synthesis in chronic intestinal inflammation.

Conclusion

The results of this study reveal differential expression of tryptophan and nicotinamide metabolism-associated genes in the distal colon and brain in Winnie mice with chronic intestinal inflammation. These data provide evidence supporting the role of tryptophan metabolism and de novo NAD+ synthesis in IBD pathophysiology.

Peyer's Patch: Possible target for modulating the Gut-Brain-Axis through microbiota

The gastrointestinal (GI) tract and the brain form bidirectional nervous, immune, and endocrine communications known as the gut-brain axis. Several factors can affect this axis; among them, various studies have focused on the microbiota and imply that alterations in microbiota combinations can influence both the brain and GI. Also, many studies have shown that the immune system has a vital role in varying gut microbiota combinations. In the current paper, we will review the multidirectional effects of gut microbiota, immune system, and nervous system on each other. Specifically, this review mainly focuses on the impact of Peyer's patches as a critical component of the gut immune system on the gut-brain axis through affecting the gut's microbial composition. In this way, some factors were discussed as proposed elements of missing gaps in this field.

Shared genetic basis and causality between schizophrenia and inflammatory bowel disease: evidence from a comprehensive genetic analysis

BACKGROUND

The comorbidity between schizophrenia (SCZ) and inflammatory bowel disease (IBD) observed in epidemiological studies is partially attributed to genetic overlap, but the magnitude of shared genetic components and the causality relationship between them remains unclear.

METHODS

By leveraging large-scale genome-wide association study (GWAS) summary statistics for SCZ, IBD, ulcerative colitis (UC), and Crohn's disease (CD), we conducted a comprehensive genetic pleiotropic analysis to uncover shared loci, genes, or biological processes between SCZ and each of IBD, UC, and CD, independently. Univariable and multivariable Mendelian randomization (MR) analyses were applied to assess the causality across these two disorders.

RESULTS

SCZ genetically correlated with IBD (rg = 0.14, p = 3.65 × 10−9), UC (rg = 0.15, p = 4.88 × 10−8), and CD (rg = 0.12, p = 2.27 × 10−6), all surpassed the Bonferroni correction. Cross-trait meta-analysis identified 64, 52, and 66 significantly independent loci associated with SCZ and IBD, UC, and CD, respectively. Follow-up gene-based analysis found 11 novel pleiotropic genes (KAT5, RABEP1, ELP5, CSNK1G1, etc) in all joint phenotypes. Co-expression and pathway enrichment analysis illustrated those novel genes were mainly involved in core immune-related signal transduction and cerebral disorder-related pathways. In univariable MR, genetic predisposition to SCZ was associated with an increased risk of IBD (OR 1.11, 95% CI 1.07–1.15, p = 1.85 × 10−6). Multivariable MR indicated a causal effect of genetic liability to SCZ on IBD risk independent of Actinobacteria (OR 1.11, 95% CI 1.06–1.16, p = 1.34 × 10−6) or BMI (OR 1.11, 95% CI 1.04–1.18, p = 1.84 × 10−3).

CONCLUSIONS

We confirmed a shared genetic basis, pleiotropic loci/genes, and causal relationship between SCZ and IBD, providing novel insights into the biological mechanism and therapeutic targets underlying these two disorders.

Ameliorated Effects of Fucoidan on Dextran Sulfate Sodium-Induced Ulcerative Colitis and Accompanying Anxiety and Depressive Behaviors in Aged C57BL/6 Mice

Fucoidan has shown better effects on the improvement of acute ulcerative colitis (UC). However, the specific mechanisms by which fucoidan improves UC-related behavioral disorders in aged mice, especially its effect on the gut-brain axis, remain to be further explored. C57BL/6 male mice aged 8 months were gavaged with 400 or 100 mg/kg bw day fucoidan for five consecutive weeks, with UC being induced by ad libitum to dextran sulfate sodium (DSS) solution in the fifth week. The results showed that fucoidan ameliorated UC and accompanying anxiety- and depressive-like behaviors with downregulated expressions of (NOD)-like receptor family and pyrin domain-containing 3 (NLRP3), apoptosis-associated speck-like protein (ASC), cysteine aspartate-specific protease-1 (Caspase-1) and interlekin-1β (IL-1β), and elevated mRNA levels of brain-derived neurotrophic factor (Bdnf) and postsynaptic-density protein 95 (Psd-95) in cortex and hippocampus. Furthermore, fucoidan improved the permeability of intestinal barrier and blood-brain barrier and restored the abnormal structure of the gut microbiota with a significantly decreased ratio of Firmicutes to Bacteroidota (F/B) and obviously increased abundance of Akkermansia. As a diet-derived bioactive ingredient, fucoidan might be a better alternative for the prevention of UC and accompanying anxiety- and depressive-like behaviors.

Irritable Bowel Syndrome Is Associated With Brain Health by Neuroimaging, Behavioral, Biochemical, and Genetic Analyses

BACKGROUND

Irritable bowel syndrome (IBS) interacts with psychopathology in a complex way; however, little is known about the underlying brain, biochemical, and genetic mechanisms.

METHODS

To clarify the phenotypic and genetic associations between IBS and brain health, we performed a comprehensive retrospective cohort study on a large population. Our study included 171,104 participants from the UK Biobank who underwent a thorough assessment of IBS, with the majority also providing neuroimaging, behavioral, biochemical, and genetic information. Multistage linked analyses were conducted, including phenome-wide association analysis, polygenic risk score calculation, and 2-sample Mendelian randomization analysis.

RESULTS

The phenome-wide association analysis showed that IBS was linked to brain health problems, including anxiety and depression, and poor cognitive performance. Significantly lower brain volumes associated with more severe IBS were found in key areas related to emotional regulation and higher-order cognition, including the medial orbitofrontal cortex/ventromedial prefrontal cortex, anterior insula, anterior and mid-cingulate cortices, dorsolateral prefrontal cortex, and hippocampus. Higher triglycerides, lower high-intensity lipoprotein, and lower platelets were also related (p < 1 × 10-10) to more severe IBS. Finally, Mendelian randomization analyses demonstrated potential causal relationships between IBS and brain health and indicated possible mediating effects of dyslipidemia and inflammation.

CONCLUSIONS

For the first time, this study provides a comprehensive understanding of the relationship between IBS and brain health phenotypes, integrating perspectives from neuroimaging, behavioral performance, biochemical factors, and genetics, which is of great significance for clinical applications to potentially address brain health impairments in patients with IBS.

Mechanisms of inflammation after ischemic stroke in brain-peripheral crosstalk

Stroke is a devastating disease with high morbidity, disability, and mortality, among which ischemic stroke is more common. However, there is still a lack of effective methods to improve the prognosis and reduce the incidence of its complications. At present, there is evidence that peripheral organs are involved in the inflammatory response after stroke. Moreover, the interaction between central and peripheral inflammation includes the activation of resident and peripheral immune cells, as well as the activation of inflammation-related signaling pathways, which all play an important role in the pathophysiology of stroke. In this review, we discuss the mechanisms of inflammatory response after ischemic stroke, as well as the interactions through circulatory pathways between peripheral organs (such as the gut, heart, lung and spleen) and the brain to mediate and regulate inflammation after ischemic stroke. We also propose the potential role of meningeal lymphatic vessels (MLVs)-cervical lymph nodes (CLNs) as a brain-peripheral crosstalk lymphatic pathway in ischemic stroke. In addition, we also summarize the mechanisms of anti-inflammatory drugs in the treatment of ischemic stroke.

Review article: A practical approach to persistent gastrointestinal symptoms in inflammatory bowel disease in remission

BACKGROUND

Persistent gastrointestinal symptoms are prevalent in adult patients with inflammatory bowel disease (IBD), even when endoscopic remission is reached. These symptoms can have profound negative effects on the quality of life of affected patients and can be difficult to treat. They may be caused by IBD-related complications or comorbid disorders, but they can also be explained by irritable bowel syndrome (IBS)-like symptoms.

AIMS

To provide a practical step-by-step guide to diagnose and treat persistent gastrointestinal symptoms in patients with IBD in remission via a personalised approach.

METHODS

We scrutinised relevant literature on causes, diagnostics and treatment of persistent gastrointestinal symptoms (abdominal pain or discomfort, bloating, abdominal distension, diarrhoea, constipation and faecal incontinence) in patients with IBD in remission.

RESULTS

A graphical practical guide for several steps in diagnosing, identifying potential triggers and adequate treatment of persistent gastrointestinal symptoms in IBD in remission is provided based on supporting literature. The first part of this review focuses on the diagnostic and treatment approaches for potential IBD-related complications and comorbidities. The second part describes the approach to IBS-like symptoms in IBD in remission.

CONCLUSIONS

Persistent gastrointestinal symptoms in IBD in remission can be traced back to potential pathophysiological mechanisms in individual patients and can be treated adequately. For both IBD-related complications and comorbidities and IBS-like symptoms in IBD in remission, pharmacological, dietary, lifestyle or psychological treatments can be effective. A systematic and personalised approach is required to reduce the burden for patients, healthcare systems, and society.

Graph Theory Further Revealed Visual Spatial Working Memory Impairment in Patients with Inflammatory Bowel Disease

Background

Inflammatory Bowel Disease (IBD) patients may experience cognitive impairments in Visuospatial Working Memory (VSWM), significantly impacting their quality of life. However, the mechanisms underlying these impairments remain poorly understood.

Methods

We studied functional MRI and graph theory analysis to investigate changes in functional connectivity networks during the Mental Rotation Task (MRT) in IBD patients. Twenty IBD patients (13 males, 7 females; mean age = 34.95 ± 13.80 years; mean disease duration = 2.43 ± 2.37 years) participated in the study. Exclusion criteria encompassed recent use of analgesics, 5-Aminosalicylate, corticosteroids, or immunosuppressants within the past three months. Additionally, we recruited 20 age-, gender-, and education-matched healthy controls for comparison.

Results

Compared to a control group, IBD patients exhibited significantly longer reaction times and reduced accuracy during the MRT. Our analysis revealed abnormalities in multiple nodal attributes within the functional connectivity network, particularly in regions such as the bilateral orbitofrontal cortex, right supplementary motor area, bilateral parahippocampal gyrus, and bilateral anterior temporal lobe. We observed that the nodal efficiency in the left temporal pole is negatively correlated with Red Blood Cell Distribution Width (RDW) and positively correlated with response time of MRT.

Conclusion

Our findings revealed notable abnormalities in multiple node attributes among IBD patients during MRT, providing evidence of cognitive impairments in VSWM in IBD patients. This study found RDW maybe can serve as a clinical indicator for predicting early VSWM impairment in patients with IBD.

Short-Chain Fatty Acids and Human Health: From Metabolic Pathways to Current Therapeutic Implications

The gastrointestinal tract is home to trillions of diverse microorganisms collectively known as the gut microbiota, which play a pivotal role in breaking down undigested foods, such as dietary fibers. Through the fermentation of these food components, short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate are produced, offering numerous health benefits to the host. The production and absorption of these SCFAs occur through various mechanisms within the human intestine, contingent upon the types of dietary fibers reaching the gut and the specific microorganisms engaged in fermentation. Medical literature extensively documents the supplementation of SCFAs, particularly butyrate, in the treatment of gastrointestinal, metabolic, cardiovascular, and gut-brain-related disorders. This review seeks to provide an overview of the dynamics involved in the production and absorption of acetate, propionate, and butyrate within the human gut. Additionally, it will focus on the pivotal roles these SCFAs play in promoting gastrointestinal and metabolic health, as well as their current therapeutic implications.

Effectiveness of Probiotic Use in Alleviating Symptoms of Irritable Bowel Syndrome: A Systematic Review

Irritable bowel syndrome (IBS) is a common functional gastrointestinal (GI) condition, and changes in the gut microbiota's composition contribute to the development of symptoms. Although the precise mechanisms of probiotic use in the human body are not fully understood, probiotic supplements are believed to reduce symptoms, such as abdominal pain, by regulating neurotransmitters and receptors associated with pain modulation in IBS patients compared to placebo by altering the gut flora. This systematic review aimed to assess the most current randomized controlled trials (RCTs) on how probiotic supplementation affects the symptoms in people with IBS. The effects of probiotic supplements on IBS symptoms were studied in RCTs published between January 2018 and June 2023. After a search through PubMed and Google Scholar using the keywords probiotics, gut microbiota, irritable bowel syndrome, and IBS; eight articles matched the inclusion criteria and were reviewed. Four trials used a multistrain probiotic, whereas the remaining four trials examined the effects of a monostrain supplement. All eight trials came to the same conclusion: Probiotic treatment may significantly reduce symptoms.

The Interaction between Stress and Inflammatory Bowel Disease in Pediatric and Adult Patients

Background: Inflammatory bowel diseases (IBDs) have seen an exponential increase in incidence, particularly among pediatric patients. Psychological stress is a significant risk factor influencing the disease course. This review assesses the interaction between stress and disease progression, focusing on articles that quantified inflammatory markers in IBD patients exposed to varying degrees of psychological stress. Methods: A systematic narrative literature review was conducted, focusing on the interaction between IBD and stress among adult and pediatric patients, as well as animal subjects. The research involved searching PubMed, Scopus, Medline, and Cochrane Library databases from 2000 to December 2023. Results: The interplay between the intestinal immunity response, the nervous system, and psychological disorders, known as the gut-brain axis, plays a major role in IBD pathophysiology. Various types of stressors alter gut mucosal integrity through different pathways, increasing gut mucosa permeability and promoting bacterial translocation. A denser microbial load in the gut wall emphasizes cytokine production, worsening the disease course. The risk of developing depression and anxiety is higher in IBD patients compared with the general population, and stress is a significant trigger for inducing acute flares of the disease. Conclusions: Further large studies should be conducted to assess the relationship between stressors, psychological disorders, and their impact on the course of IBD. Clinicians involved in the medical care of IBD patients should aim to implement stress reduction practices in addition to pharmacological therapies.

Short-term Psychodynamic Psychotherapy in Addition to Standard Medical Therapy Increases Clinical Remission in Adolescents and Young Adults with Inflammatory Bowel Disease: a Randomised Controlled Trial

BACKGROUND

Inflammatory bowel diseases [IBD] are chronic and pervasive conditions of the gastrointestinal tract with a rising incidence in paediatric and young adult populations. Evidence suggests that psychological disorders might be associated with relapse of disease activity. This study aims to evaluate the efficacy of short-term psychodynamic psychotherapy [STPP] in addition to standard medical therapy [SMT] in maintaining clinical remission in adolescents and young adults [AYA] with quiescent IBD, compared with SMT alone.

METHODS

A two-arm, single-centre, randomised, controlled trial was conducted in 60 IBD AYA in clinical remission. Patients were randomised to receive an 8-week STPP + SMT [n = 30] or SMT alone [n = 30]. The primary outcome was the steroid-free remission rate at 52 weeks after treatment. Secondary outcomes included the overall hospitalisation rate within 52 weeks after treatment, and medication adherence obtained from patient's electronic medical records.

RESULTS

Intention-to-treat analysis showed significant improvement in maintaining disease remission rates in the 8-week STPP + SMT group compared with the control one. The proportion of patients maintaining steroid-free remission at 52 weeks was higher in patients in STTP group [93.1%] compared with patients randomised to control group [64.3%; p = 0.01]. There were no significant differences in secondary outcomes, except for depression reduction in STPP + SMT group.

CONCLUSIONS

An 8-week STPP intervention in addition to SMT effectively increases the steroid-free remission rates in AYA with quiescent IBD. Results do not support effects for other secondary outcomes, except for depression reduction.

The role of gut microbiota in intestinal disease: from an oxidative stress perspective

Recent studies have indicated that gut microbiota-mediated oxidative stress is significantly associated with intestinal diseases such as colorectal cancer, ulcerative colitis, and Crohn's disease. The level of reactive oxygen species (ROS) has been reported to increase when the gut microbiota is dysregulated, especially when several gut bacterial metabolites are present. Although healthy gut microbiota plays a vital role in defending against excessive oxidative stress, intestinal disease is significantly influenced by excessive ROS, and this process is controlled by gut microbiota-mediated immunological responses, DNA damage, and intestinal inflammation. In this review, we discuss the relationship between gut microbiota and intestinal disease from an oxidative stress perspective. In addition, we also provide a summary of the most recent therapeutic approaches for preventing or treating intestinal diseases by modifying gut microbiota.

Global evolving patterns and cross-country inequalities of inflammatory bowel disease burden from 1990 to 2019: a worldwide report

AIMS

Inflammatory bowel disease (IBD) is a global disease. We aim to summarize the latest epidemiological patterns of IBD at the national, regional and global levels to give well-deserved attention and outline facilitating measures to reduce the disease burden.

METHODS

We collected the incidence, prevalence, mortality and disability-adjusted life years (DALYs) of IBD in 204 countries and territories from 1990 to 2019 using data from the Global Burden of Disease Study 2019. We further calculated the estimated annual percentage change (EAPC) to qualify the temporal trends of IBD burden by sex, age and region over the past 30 years.

RESULTS

Globally, a total of 404.55 thousand incident cases, 4898.56 thousand prevalent cases, 41.00 thousand deaths and 1622.50 thousand DALYs of IBD were estimated in 2019. The age-standardized DALYs decreased from 27.2 in 1990 to 20.15 per 100,000 people in 2019, with an EAPC of -1.04. The high socio-demographic index regions presented pronounced age-standardized rates (ASRs) consistently over the last 30 years. The high-income North America had the highest ASRs in 2019, followed by Western Europe and Australasia. No gender difference was observed after being stratified by sex.

CONCLUSIONS

The accumulated IBD patients are expected to increase in the future due to the increased rate of IBD in developing countries, and social aging in developed countries. Understanding the changes in epidemiological patterns helps to provide evidence to mitigate the rising burden of IBD.

Postbiotics: An alternative and innovative intervention for the therapy of inflammatory bowel disease

Inflammatory Bowel Disease (IBD) is a persistent gastrointestinal (GI) tract inflammatory disease characterized by downregulated mucosal immune activities and a disrupted microbiota environment in the intestinal lumen. The involvement of bacterium postbiotics as mediators between the immune system and gut microbiome could be critical in determining why host-microbial relationships are disrupted in IBD. Postbiotics including Short-chain fatty acids (SCFAs), Organic acids, Proteins, Vitamins, Bacteriocins, and Tryptophan (Trp) are beneficial bioactive compounds formed via commensal microbiota in the gut environment during the fermentation process that can be used to improve consumer health. The use of metabolites or fragments from microorganisms can be a very attractive treatment and prevention technique in modern medicine. Postbiotics are essential in the immune system's development since they alter the barrier tightness, and the gut ecology and indirectly shape the microbiota's structure. As a result, postbiotics may be beneficial in treating or preventing various diseases, even some for which there is no effective causative medication. Postbiotics may be a promising tool for the treatment of IBD in individuals of all ages, genders, and even geographical locations. Direct distribution of postbiotics may provide a new frontier in microbiome-based therapy for IBD since it allows both the management of host homeostasis and the correction of the negative implications of dysbiosis. Further studies of the biological effects of these metabolites are expected to reveal innovative applications in medicine and beyond. This review attempts to explore the possible postbiotic-based interventions for the treatment of IBD.

Exploring the Interconnections of Functional Gut Disorders and Inflammatory Bowel Disease: A Narrative Review Article

This review reveals details of the interaction between disorders of gut-brain interaction (DGBI) and inflammatory bowel disease (IBD) by providing an in-depth review of that relationship. The review provides a nuanced understanding of this multifaceted dynamic by spanning shared symptomatology, the impact of inflammation on functional aspects, and addressing diagnostic challenges, psychological influences, treatment strategies, and emerging research directions. By synthesizing current knowledge and identifying gaps in understanding, this article aims to contribute to the evolving discourse surrounding the interplay between IBD and DGBI, offering valuable insights for clinicians, researchers, and healthcare professionals navigating the complexities of gastrointestinal health.

Rice bran extract mitigates depressive-like behavior in dextran sulfate sodium-induced colitis: Involvement of the gut-brain axis and Sirt1 signaling pathway

Inflammatory bowel disease (IBD) patients frequently suffer from depressive disorders as well. The present study was carried out to explore whether treatment with a standardized rice bran extract (RBE) could affect depression-like behavior in rats with dextran sulfate sodium (DSS)-induced colitis. Male Wistar rats were treated with RBE (100 mg/kg/day; p.o.) for 2 weeks. During the second week, colitis was induced by feeding the rats with 5 % (w/v) DSS in drinking water. RBE protected against DSS-induced body weight loss as well as against the macro- and microscopic inflammatory changes of the colon. Additionally, RBE mitigated DSS-induced dysregulation in blood-brain barrier tight junctional proteins, preserved the hippocampal histopathological architecture and improved the animal behavior in the forced swimming test. This was associated with modulation of hippocampal oxidative stress marker; GSH as well as hippocampal pro-inflammatory mediators; NF-ĸB and IL-1β. Treatment with RBE also led to a profound increase in the hippocampal levels of Sirt1, PGC-1α, Nrf2, and HO-1, which were drastically dropped by DSS. In conclusion, the study revealed the protective effect of RBE against DSS-induced depressive-like behavior through modulation of different parameters along the gut-brain axis and up-regulated the Sirt1/PGC-1α/Nrf2/HO-1 signaling pathway.

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.

Psychiatric Comorbidities of Inflammatory Bowel Disease: It Is a Matter of Microglia's Gut Feeling

Inflammatory bowel disease (IBD), a common term for Crohn's disease and ulcerative colitis, is a chronic, relapse-remitting condition of the gastrointestinal tract that is increasing worldwide. Psychiatric comorbidities, including depression and anxiety, are more prevalent in IBD patients than in healthy individuals. Evidence suggests that varying levels of neuroinflammation might underlie these states in IBD patients. Within this context, microglia are the crucial non-neural cells in the brain responsible for innate immune responses following inflammatory insults. Alterations in microglia's functions, such as secretory profile, phagocytic activity, and synaptic pruning, might play significant roles in mediating psychiatric manifestations of IBD. In this review, we discuss the role played by microglia in IBD-associated comorbidities.