Bidirectional brain-gut axis effects influence mood and prognosis in IBD: a systematic review and meta-analysis

Effect of antidepressants on psychological comorbidities, disease activity, and quality of life in inflammatory bowel disease: a systematic review and meta-analysis

Background

Patients with inflammatory bowel disease (IBD) are often accompanied by a more significant burden of depression or anxiety, and approximately one-third are prescribed antidepressants. However, previous studies on the efficacy of antidepressants in IBD have shown inconsistent results.

Objectives

To evaluate the effect of antidepressants on depression, anxiety, disease activity, and quality of life (QoL) in IBD patients.

Design

A systematic review and meta-analysis.

Methods

We searched MEDLINE via Ovid, EMBASE via Ovid, the Cochrane Library, CINAHL, PsycINFO, Chinese CBM Database, China National Knowledge Infrastructure, VIP, and Wanfang Database from inception to 13th July 2022 without language restrictions.

Results

In all, 13 studies containing 884 individuals were included. Compared with the control group, antidepressants were superior in reducing depression scores [standardized mean difference (SMD) = -0.791; 95% confidence interval (CI): -1.009 to -0.572; p < 0.001], anxiety scores (SMD = -0.877; 95% CI: -1.203 to -0.552; p < 0.001), and disease activity scores (SMD = -0.323; 95% CI: -0.500 to -0.145; p < 0.001). Antidepressants had a positive effect in reaching clinical remission [risk ratio (RR) = 1.383; 95% CI: 1.176-1.626; p < 0.001]. Higher physical QoL (SMD = 0.578; 95% CI: 0.025-1.130; p = 0.040), social QoL (SMD = 0.626; 95% CI: 0.073-1.180; p = 0.027), and Inflammatory Bowel Disease Questionnaire (SMD = 1.111; 95% CI: 0.710-1.512; p < 0.001) were found in the experimental group. No significant differences were observed in clinical response (RR = 1.014; 95% CI: 0.847-1.214; p = 0.881), psychological QoL (SMD = 0.399; 95% CI: -0.147 to 0.944; p = 0.152), and environmental QoL (SMD = 0.211; 95% CI: -0.331 to 0.753; p = 0.446).

Conclusion

Antidepressants are effective for ameliorating depression, anxiety, disease activity, and QoL in IBD patients. Due to most studies having a small sample size, further well-designed studies are required.

Assembly and analytical validation of a metagenomic reference catalog of human gut microbiota based on co-barcoding sequencing

Human gut microbiota is associated with human health and disease, and is known to have the second-largest genome in the human body. The microbiota genome is important for their functions and metabolites; however, accurate genomic access to the microbiota of the human gut is hindered due to the difficulty of cultivating and the shortcomings of sequencing technology. Therefore, we applied the stLFR library construction method to assemble the microbiota genomes and demonstrated that assembly property outperformed standard metagenome sequencing. Using the assembled genomes as references, SNP, INDEL, and HGT gene analyses were performed. The results demonstrated significant differences in the number of SNPs and INDELs among different individuals. The individual displayed a unique species variation spectrum, and the similarity of strains within individuals decreased over time. In addition, the coverage depth analysis of the stLFR method shows that a sequencing depth of 60X is sufficient for SNP calling. HGT analysis revealed that the genes involved in replication, recombination and repair, mobilome prophages, and transposons were the most transferred genes among different bacterial species in individuals. A preliminary framework for human gut microbiome studies was established using the stLFR library construction method.

Depression and anxiety in inflammatory bowel disease: epidemiology, mechanisms and treatment

Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, is a chronic, relapsing immune-mediated disease with a varying and sometimes severe disease course. IBD is often diagnosed in early adulthood and can lead to a substantial decline in quality of life. It has been suggested that patients with IBD are at increased risk of depression and anxiety, but it is still unclear to what extent these diseases co-occur and in what sequence they arise. This Review summarizes the literature on the degree of co-occurrence of IBD with depression and anxiety and the temporal relationship between these diseases. We also discuss the effect of psychological stress on the onset and course of IBD. In addition, we outline the possible mechanisms underlying the co-occurrence of IBD and depression and anxiety, which include changes in brain signalling and morphology, increases in peripheral and intracerebral pro-inflammatory cytokines, impairment of the nitric oxide pathway, changes in vagal nerve signalling, gut dysbiosis and genetics. Finally, we examine the possible effects of treatment of depression and anxiety on the risk and course of IBD, the influence of psychological interventions on IBD, and the effects of IBD treatment on psychiatric comorbidity.

Effect of 5-Hydroxytryptophan on Fatigue in Quiescent Inflammatory Bowel Disease: A Randomized Controlled Trial

BACKGROUND & AIMS

Fatigue is highly prevalent among patients with inflammatory bowel disease (IBD), and only limited treatment options are available. Based on the hypothetical link between low serum tryptophan concentrations and fatigue, we determined the effect of 5-hydroxytryptophan supplementation on fatigue in patients with inactive IBD.

METHODS

A multicenter randomized controlled trial was performed at 13 Belgian hospitals, including 166 patients with IBD in remission but experiencing fatigue, defined by a fatigue visual analog scale (fVAS) score of ≥5. Patients were treated in a crossover manner with 100 mg oral 5-hydroxytryptophan or placebo twice daily for 2 consecutive periods of 8 weeks. The primary end point was the proportion of patients reaching a ≥20% reduction in fVAS after 8 weeks of intervention. Secondary outcomes included changes in serum tryptophan metabolites, Functional Assessment of Chronic Illness Therapy Fatigue scale, and scores for depression, anxiety, and stress. The effect of the intervention on the outcomes was evaluated by linear mixed modeling.

RESULTS

During 5-hydroxytryptophan treatment, a significant increase in serum 5-hydroxytryptophan (estimated mean difference, 52.66 ng/mL; 95% confidence interval [CI], 39.34-65.98 ng/mL; P < .001) and serotonin (3.0 ng/mL; 95 CI, 1.97-4.03 ng/mL; P < .001) levels was observed compared with placebo. The proportion of patients reaching ≥20% reduction in fVAS was similar in placebo- (37.6%) and 5-hydroxytryptophan (35.6%)-treated patients (P = .830). The fVAS reduction (-0.18; 95% CI, -0.81 to 0.46; P = .581) and Functional Assessment of Chronic Illness Therapy Fatigue scale increase (0.68; 95% CI, -2.37 to 3.73; P = .660) were both comparable between 5-hydroxytryptophan and placebo treatment as well as changes in depression, anxiety, and stress scores.

CONCLUSIONS

Despite a significant increase in serum 5-hydroxytryptophan and serotonin levels, oral 5-hydroxytryptophan did not modulate IBD-related fatigue better than placebo. (Trial Registration: Belgian Federal Agency for Medication and Health Products, EudraCT number: 2017-005059-10 and ClinicalTrials.gov: NCT03574948, https://clinicaltrials.gov/ct2/show/NCT03574948.).

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.

The Gut–Immune–Brain Axis: An Important Route for Neuropsychiatric Morbidity in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) comprises Crohn’s disease (CD) and ulcerative colitis (UC) and is associated with neuropsychiatric symptoms like anxiety and depression. Both conditions strongly worsen IBD disease burden. In the present review, we summarize the current understanding of the pathogenesis of depression and anxiety in IBD. We present a stepwise cascade along a gut–immune–brain axis initiated by evasion of chronic intestinal inflammation to pass the epithelial and vascular barrier in the gut and cause systemic inflammation. We then summarize different anatomical transmission routes of gut-derived peripheral inflammation into the central nervous system (CNS) and highlight the current knowledge on neuroinflammatory changes in the CNS of preclinical IBD mouse models with a focus on microglia, the brain-resident macrophages. Subsequently, we discuss how neuroinflammation in IBD can alter neuronal circuitry to trigger symptoms like depression and anxiety. Finally, the role of intestinal microbiota in the gut–immune–brain axis in IBD will be reviewed. A more comprehensive understanding of the interaction between the gastrointestinal tract, the immune system and the CNS accounting for the similarities and differences between UC and CD will pave the path for improved prediction and treatment of neuropsychiatric comorbidities in IBD and other inflammatory diseases.

Relative Contribution of Disease Activity and Psychological Health to Prognosis of Inflammatory Bowel Disease During 6.5 Years of Longitudinal Follow-Up

BACKGROUND & AIMS

Symptoms of common mental disorders, such as anxiety or depression, are common in inflammatory bowel disease (IBD) and may affect prognosis. However, unlike clinical or biochemical markers of disease activity, psychological health is not a recommended therapeutic target. We assessed relative contribution of poor psychological health and clinical or biochemical activity to prognosis.

METHODS

Demographic features, IBD subtype, treatments, and anxiety and depression scores were recorded at baseline for 760 adults, with clinical activity determined using validated scoring systems. Fecal calprotectin was analyzed in 379 (49.9%) patients (≥250 μg/g used to define biochemical activity). Glucocorticosteroid prescription or flare, escalation, hospitalization, intestinal resection, or death were assessed during 6.5 years of follow-up. Occurrence was compared using multivariate Cox regression across 4 patient groups according to presence of disease remission or activity, with or without symptoms of a common mental disorder, at baseline.

RESULTS

In total, 718 (94.5%) participants provided data. Compared with clinical remission without symptoms of a common mental disorder at baseline, need for glucocorticosteroid prescription or flare (hazard ratio [HR], 2.36; 95% confidence interval [CI], 1.58-3.54), escalation (HR, 1.65; 95% CI, 1.14--2.40), and death (HR, 4.99; 95% CI, 1.80-13.88) were significantly higher in those with clinical activity and symptoms of a common mental disorder. Rates in those with clinical remission and symptoms of a common mental disorder at baseline or those with clinical activity without symptoms of a common mental disorder were not significantly higher. Similarly, with biochemical activity and symptoms of a common mental disorder, rates of glucocorticosteroid prescription or flare (HR, 2.48; 95% CI, 1.38-4.46), escalation (HR, 2.97; 95% CI, 1.74-5.06), hospitalization (HR, 3.10; 95% CI, 1.43-6.68), and death (HR, 6.26; 95% CI, 2.23-17.56) were significantly higher.

CONCLUSIONS

Psychological factors are important determinants of poor prognostic outcomes in IBD and should be considered as a therapeutic target.

Brain-immune axis regulation is responsive to cognitive behavioral therapy and mindfulness intervention: Observations from a randomized controlled trial in patients with Crohn's disease

Background and aims

Crohn's disease (CD) is a chronic inflammatory bowel disease associated with psychological stress that is regulated primarily by the hypothalamus-pituitary-adrenal (HPA) axis. Here, we determined whether the psychological characteristics of CD patients associate with their inflammatory state, and whether a 3-month trial of cognitive-behavioral and mindfulness-based stress reduction (COBMINDEX) impacts their inflammatory process.

Methods

Circulating inflammatory markers and a wide range of psychological parameters related to stress and well-being were measured in CD patients before and after COBMINDEX. Inflammatory markers in CD patients were also compared to age- and sex-matched healthy controls (HCs).

Results

CD patients exhibited increased peripheral low-grade inflammation compared with HCs, demonstrated by interconnected inflammatory modules represented by IL-6, TNFα, IL-17, MCP-1 and IL-18. Notably, higher IL-18 levels correlated with higher score of stress and a lower score of wellbeing in CD patients. COBMINDEX was accompanied by changes in inflammatory markers that coincided with changes in cortisol: changes in serum levels of cortisol correlated positively with those of IL-10 and IFNα and negatively with those of MCP-1. Furthermore, inflammatory markers of CD patients at baseline predicted COBMINDEX efficacy, as higher levels of distinct cytokines and cortisol at baseline, correlated negatively with changes in disease activity (by Harvey-Bradshaw Index) and psychological distress (global severity index measure) following COBMINDEX.

Conclusion

CD patients have a characteristic immunological profile that correlates with psychological stress, and disease severity. We suggest that COBMINDEX induces stress resilience in CD patients, which impacts their well-being, and their disease-associated inflammatory process.

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Patients with Crohn's disease exhibit distinct inflammatory and psychological modules.

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IL-18 correlates with clinical and psychological features of patients with Crohn's disease.

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COBMINDEX treatment strengthens resilience and recovers stress-induced inflammation among Crohn's disease patients.

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Both inflammatory and psychological measures predict COBMINDEX efficacy.