Evidence for the role of the brain-gut axis in inflammatory bowel disease: depression as cause and effect?

Randomized controlled trial of an Acceptance and Commitment Therapy and compassion-based group intervention for persons with inflammatory bowel disease: the LIFEwithIBD intervention

Objectives

This study tested the acceptability and efficacy of an Acceptance and Commitment Therapy and compassion-based intervention (LIFEwithIBD) in people with IBD through a two-arm RCT.

Methods

Participants were recruited at the Gastroenterology Department of the Coimbra University Hospital between June and September 2019. Of the 355 patients screened, those who accepted to participate were randomly assigned to one of two conditions: experimental group (LIFEwithIBD; n = 25) or control group (waitlist; n = 29). Participants completed self-report measures at baseline (T0), post-intervention (T1), and 3-month (T2) and 12-month (T3) follow-ups. Intervention acceptability was assessed. Efficacy was examined using intent-to-treat ANCOVA at post-intervention after adjusting for baseline values of depressive, anxiety, and stress symptoms (primary outcomes). Linear mixed models for all longitudinal outcomes were also analysed. Inflammatory and disease biomarkers were determined at T0 and T3.

Results

Acceptability results revealed a high level of satisfaction and perceived usefulness regarding the intervention. Both groups experienced a significant decrease in stress symptoms and IBD symptom perception at T1. No significant differences were observed at follow-up for the primary outcomes. The experimental group reported significantly lower Crohn's disease Symptom severity at T2 than the control group. Post-hoc analyses designed to mitigate floor effects revealed substantial treatment effects for the experimental group regarding anxiety symptoms. No significant differences were observed in clinical biomarkers from T0 to T3.

Conclusion

The LIFEwithIBD intervention shows promising, although preliminary, benefits for managing disease activity and reducing anxiety symptoms in IBD patients with high severity of psychological distress.Clinical trial registration: https://www.clinicaltrials.gov/ct2/show/NCT03840707, identifier NCT03840707.

Promising new pharmacological targets for depression: The search for efficacy

Pharmacological treatment of major depressive disorder (MDD) still relies on the use of serotonergic drugs, despite their limited efficacy. A few mechanistically new drugs have been developed in recent years, but many fail in clinical trials. Several hypotheses have been proposed to explain MDD pathophysiology, indicating that physiological processes such as neuroplasticity, circadian rhythms, and metabolism are potential targets. Here, we review the current state of pharmacological treatments for MDD, as well as the preclinical and clinical evidence for an antidepressant effect of molecules that target non-serotonergic systems. We offer some insights into the challenges facing the development of new antidepressant drugs, and the prospect of finding more effectiveness for each target discussed.

Gut instincts in neuroimmunity from the eighteenth to twenty-first centuries

In the past two decades, work on the microbiota-gut-brain axis has led to a renewed appreciation for the interconnectedness between body systems in both clinical and scientific circles. In the USA alone, millions of adults are burdened with non-communicable chronic diseases whose putative etiologies were previously thought to be restricted to either the gut or brain, such as inflammatory bowel disease, irritable bowel syndrome, Parkinson's and Alzheimer's disease, and autism spectrum disorder. However, the recent explosion of research into the impacts of the gut microbiome on diverse aspects of human health has revealed the potentially critical importance of reciprocal interactions between the gut microbiota, the immune system, and the brain in diverse diseases and disorders. In this review, we revisit the history of gut-brain interactions in science and medicine, which dates back to at least the eighteenth century, and outline how concepts in this field have shifted and evolved across eras. Next, we highlight the modern resurgence of gut-brain axis research, focusing on neuro-immune-microbiota interactions and recent progress towards a mechanistic understanding of the diverse impacts of the microbiome on human health. Finally, we offer a forward-looking perspective on the future of microbiota-gut-brain research, which may eventually reveal new paths towards the treatment of diverse diseases influenced by the complex connections between the microbiota and the brain.

The ethanol extract of Periplaneta Americana L. improves ulcerative colitis induced by a combination of chronic stress and TNBS in rats

Purpose:

To investigate the effects of Periplaneta americana L. on ulcerative colitis (UC) induced by a combination of chronic stress (CS) and 2,4,6-trinitrobenzene sulfonic acid enema (TNBS) in rats.

Methods:

The experiment UC model with CS was established in rats by a combination of chronic restraint stress, excess failure, improper, and TNBS. The body weight, disease activity index (DAI), colonic mucosal injury index (CMDI), histopathological score (HS) and pro-inflammatory mediators were measured. The content of corticotropin-releasing hormone (CRH) in hypothalamus or adrenocorticotropic hormone (ACTH) and corticosteroids (CORT) in plasma were evaluated by enzyme-linked immunosorbent assay. The proportion of T lymphocyte subsets was detected by flow cytometry, and gut microbiota was detected by 16S rDNA amplicon sequencing.

Results:

Weight loss, DAI, CMDI, HS and proinflammatory mediators were reversed in rats by P. americana L. treatment after UC with CS. Increased epidermal growth factor (EGF) was observed in P. americana L. groups. In addition, P. americana L. could reduce the content of CRH and ACTH and regulate the ratio of CD3⁺, CD3⁺CD8⁺ and CD3⁺CD4⁺CD25⁺/CD4⁺ in spleen. Comparably, P. americana L. changes composition of gut microbiota.

Conclusions:

The ethanol extract of Periplaneta Americana L. improves UC induced by a combination of CS and TNBS in rats.

Treatment of Gastrointestinal Disorders-Plants and Potential Mechanisms of Action of Their Constituents

The worldwide prevalence of gastrointestinal diseases is about 40%, with standard pharmacotherapy being long-lasting and economically challenging. Of the dozens of diseases listed by the Rome IV Foundation criteria, for five of them (heartburn, dyspepsia, nausea and vomiting disorder, constipation, and diarrhoea), treatment with herbals is an official alternative, legislatively supported by the European Medicines Agency (EMA). However, for most plants, the Directive does not require a description of the mechanisms of action, which should be related to the therapeutic effect of the European plant in question. This review article, therefore, summarizes the basic pharmacological knowledge of synthetic drugs used in selected functional gastrointestinal disorders (FGIDs) and correlates them with the constituents of medicinal plants. Therefore, the information presented here is intended as a starting point to support the claim that both empirical folk medicine and current and decades-old treatments with official herbal remedies have a rational basis in modern pharmacology.

Gut microbiota and neuropsychiatric disorders: Implications for neuroendocrine-immune regulation

Recently, increasing evidence has shown gut microbiota dysbiosis might be implicated in the physiological mechanisms of neuropsychiatric disorders. Altered microbial community composition, diversity and distribution traits have been reported in neuropsychiatric disorders. However, the exact pathways by which the intestinal microbiota contribute to neuropsychiatric disorders remain largely unknown. Given that the onset and progression of neuropsychiatric disorders are characterized with complicated alterations of neuroendocrine and immunology, both of which can be continually affected by gut microbiota via "microbiome-gut-brain axis". Thus, we assess the complicated crosstalk between neuroendocrine and immunological regulation might underlie the mechanisms of gut microbiota associated with neuropsychiatric disorders. In this review, we summarized clinical and preclinical evidence on the role of the gut microbiota in neuropsychiatry disorders, especially in mood disorders and neurodevelopmental disorders. This review may elaborate the potential mechanisms of gut microbiota implicating in neuroendocrine-immune regulation and provide a comprehensive understanding of physiological mechanisms for neuropsychiatric disorders.

Investigation of early and lifetime clinical features and comorbidities for the risk of developing treatment-resistant depression in a 13-year nationwide cohort study

BACKGROUND

To investigate the risk of treatment-resistant depression (TRD) in patients with depression by examining their clinical features, early prescription patterns, and early and lifetime comorbidities.

METHODS

In total, 31,422 depressive inpatients were followed-up from diagnostic onset for more than 10-years. Patients were diagnosed with TRD if their antidepressant treatment regimen was altered ≥two times or if they were admitted after at least two different antidepressant treatments. Multiple Cox regression model were used to determine whether physical and psychiatric comorbidities, psychosis, and prescription patterns increased the risk of TRD by controlling for relevant demographic covariates. Survival analyses were performed for important TRD-associated clinical variables.

RESULTS

Females with depression (21.24%) were more likely to suffer from TRD than males (14.02%). Early anxiety disorders were more commonly observed in the TRD group than in the non-TRD group (81.48 vs. 58.96%, p < 0.0001). Lifetime anxiety disorders had the highest population attributable fraction (42.87%). Seventy percent of patients with multiple psychiatric comorbidities developed TRD during follow-up. Cox regression analysis further identified that functional gastrointestinal disorders significantly increased TRD risk (aHR = 1.19). Higher doses of antidepressants and benzodiazepines and Z drugs in the early course of major depressive disorder increased TRD risk (p < 0.0001).

CONCLUSION

Our findings indicate the need to monitor early comorbidities and polypharmacy patterns in patients with depression associated with elevated TRD risk.

The influence of self-criticism on depression symptoms among ambulatory patients with inflammatory bowel disease

Considering that self-criticism is an important process in the development and maintenance of depression, and taking into account the stigma associated with inflammatory bowel disease (IBD), the present study aimed to analyse whether self-criticism exacerbates the relationships of depression symptoms with IBD symptomatology and chronic illness-related shame. The sample included 53 ambulatory IBD patients (66% females) with ages from 18 to 65. Moderation analyses were conducted using structural equation modelling. Self-criticism exacerbated the associations of depression with IBD symptoms (b = 0.01; standard error [SE] = 0.00; Z = 3.73; P < .001) and illness shame (b = 0.02; SE = 0.01; Z = 2.40; P = .016). For the same level of IBD symptomatology or chronic illness-related shame, those individuals who present more feelings of inadequacy towards the self, experience more symptoms of depression. This exacerbation effect is stronger when IBD symptomatology and chronic illness-related shame are more intense. A high self-critical IBD patient may view the illness and/or symptomatology as a flaw or error that should be self-corrected. Physicians and other health professionals should be attentive to these pathological mechanisms and should attempt to alleviate them. It may be beneficial to refer high self-critical patients to psychological care.

Ghrelin exhibited antidepressant and anxiolytic effect via the p38-MAPK signaling pathway in hippocampus

Ghrelin, a peptide derived from stomach, is an endogenous ligand for growth hormone secretagogue receptor (GHSR). So far, the exact role of ghrelin in depression and anxiety is still being debated. The p38 mitogen-activated protein kinase (p38-MAPK) is known to be activated in response to various stress stimuli. Thus, we hypothesize that ghrelin has an antidepressant effect, to which the p38-MAPK signaling pathway significantly contributes. To test this hypothesis, chronic social defeat stress (CSDS) was used as a model of depression. We employed the adeno-associated virus-mediated siRNA approach to down-regulate GHSR expression in the hippocampus of mice in vivo. Both ghrelin and the p38 inhibitor, SB203580, were administered to identify the effect of ghrelin on depressive-like behavior of stressed mice and to better assess the role of the p38-MAPK signaling pathway in this process. We found that CSDS activated the endogenous ghrelin-GHSR in hippocampal neurons, which possibly resulted in opposing the formation of depression- and anxiety-like behaviors in mice. Furthermore, the p38-MAPK signaling pathway had an important role in the antidepressant effect of ghrelin. Therefore, we conclude that ghrelin may reduce CSDS-induced depression- and anxiety-like behaviors via inhibiting the p38-MAPK signaling pathway in hippocampal neurons of mice.

Involvement of central opioid receptors in protective effects of methadone on experimental colitis in rats

PURPOSE

There are several lines of evidence on the protective roles of opioids in gastrointestinal inflammatory conditions. This study aims to distinguish the central and peripheral roles of methadone, a non-selective opioid receptor agonist, in an acute model of ulcerative colitis in male rats.

METHODS

Ulcerative colitis was induced by intrarectal administration of acetic acid 4%. Methadone was injected subcutaneously (s.c.), 5 and 10 mg/kg, and intracerebroventricular (i.c.v.), 50 and 300 ng/rat. Opioid antagonists were employed. Methylnaltrexone (MNTX; 5 mg/kg, i.p.), a peripherally acting opioid receptor antagonist, and naltrexone (NTX; 5 mg/kg, i.p. and 10 ng/rat, i.c.v.), a peripherally and centrally acting opioid receptor antagonist were injected before methadone (10 mg/kg, s.c. and or 300 ng/rat, i.c.v.) administration. NTX (5 mg/kg, i.p. and 10 ng/rat, i.c.v.) were administered 30 min prior to administration of methadone (10 mg/kg, s.c. and 300 ng/rat, i.c.v.), respectively. MNTX (5 mg/kg, i.p.) was injected 30 min prior to methadone (10 mg/kg, s.c.). Seventy-two hours following colitis induction, macroscopic and microscopic mucosal lesions, and the colonic levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) were determined.

RESULTS

Methadone (300 ng/rat, i.c.v.) and Methadone (5 and 10 mg/kg, s.c.) improved the macroscopic and microscopic scores through opioid receptors. Also, a significant reduction in TNF-α and IL-1β was observed. Peripherally and centrally injected NTX significantly reversed methadone 10 mg/kg s.c. anti-inflammatory effects while MNTX could not completely reverse this effect. Moreover, centrally administered methadone (300 ng/rat) showed the anti-inflammatory effect which was reversed by central administration of NTX (10 ng/rat).

CONCLUSIONS

The opioid receptors mainly the central opioid receptors may mediate the protective actions of methadone on the experimental model of inflammatory bowel disease in rat.

An 18-month study of the effects of IBD symptomatology and emotion regulation on depressed mood

PURPOSE

Depressive symptomatology in IBD patients is known to predict disease activity, which, in turn, can increase depressive symptoms in perpetuating a cycle between depression and IBD symptomatology. The mechanisms that contribute to the relationship between disease activity and depressive symptoms are not clearly investigated yet. Since emotion regulation has been considered particularly relevant to define the impact of adverse experiences on different outcomes, the current study aimed to examine the longitudinal influence of two maladaptive emotion regulation processes, cognitive fusion and brooding, on the association between disease activity and depressed mood.

METHODS

This study was conducted over an 18-month period, using a sample of 116 IBD patients that completed self-report validated measures in three different waves. Correlation analyses and cross-lagged panel models were performed.

RESULTS

The main result from this study discovered that the experience of IBD symptomatology at baseline, although positively linked to the manifestation of depressed mood 18 months later (r = 0.25; p < 0.01), does not directly predict depressive symptoms. This relationship is rather indirect, as it is explained by the engagement in cognitive fusion (p = 0.028) and brooding (p = 0.017). These maladaptive emotion regulation processes, that were revealed to be consistent over time, link IBD symptoms with subsequent depressed mood.

CONCLUSIONS

These findings indicate that clinicians should be aware of the emotion regulation processes patients tend to use to handle difficult experiences. The inclusion of psychological assessments and interventions in the healthcare of IBD patients should be seriously considered. Further implications are discussed.

Cognitive impairment in Crohn's disease is associated with systemic inflammation, symptom burden and sleep disturbance

BACKGROUND

Patients with Crohn's disease (CD) frequently complain of cognitive difficulties such as problems with concentration and clouding of thought, yet this has scarcely been objectively defined and underlying mechanisms remain unknown.

OBJECTIVE

The objective of this article is to objectively measure cognitive impairments in patients with CD compared with healthy controls, and if present, to identify potentially modifiable, contributing factors associated with cognitive impairment.

METHODS

CD patients and healthy age-/sex-matched controls completed surveys encompassing clinical, demographic, psychiatric, fatigue and sleep parameters. Contemporaneously, disease activity assessment with serum CRP, faecal calprotectin, Harvey-Bradshaw Index and the Subtle Cognitive Impairment test (SCIT) were performed, with the primary measure of response time (SCIT-RT) compared between groups. Multiple linear regression assessed for factors associated with slower SCIT-RT, denoting subtle cognitive impairment.

RESULTS

A total of 49 CD and 31 control individuals participated, with median age 44 years (range 22-65) and 43 years (21-63), respectively. Compared to controls, SCIT-RT was slower across all timepoints in CD patients (ANOVA p < 0.001). In multivariate analysis, serum CRP (standardised beta coefficient 0.27, 95% CI (0.02, 0.51)), abdominal pain (0.43 (0.16, 0.70)), plasma haemoglobin (1.55 (1.42, 1.68)), and concurrent fatigue (0.56 (0.25, 0.88)) were each independently associated with slower SCIT-RT in CD (each p < 0.05), with a trend for poorer sleep quality 0.54 (-0.03, 1.11) (p = 0.06), yet conversely, higher faecal calprotectin titres were associated with faster SCIT-RT (-1.77 (-1.79, -1.76), p < 0.01).

CONCLUSIONS

Patients with CD demonstrated subtle cognitive impairment utilising the objective SCIT, correlating with systemic inflammation and other disease burden measures, although higher faecal calprotectin titres were unexpectedly associated with less cognitive impairment.

Role of Corticotropin-releasing Factor Signaling in Stress-related Alterations of Colonic Motility and Hyperalgesia

The corticotropin-releasing factor (CRF) signaling systems encompass CRF and the structurally related peptide urocortin (Ucn) 1, 2, and 3 along with 2 G-protein coupled receptors, CRF₁ and CRF₂. CRF binds with high and moderate affinity to CRF₁ and CRF₂ receptors, respectively while Ucn1 is a high-affinity agonist at both receptors, and Ucn2 and Ucn3 are selective CRF₂ agonists. The CRF systems are expressed in both the brain and the colon at the gene and protein levels. Experimental studies established that the activation of CRF₁ pathway in the brain or the colon recaptures cardinal features of diarrhea predominant irritable bowel syndrome (IBS) (stimulation of colonic motility, activation of mast cells and serotonin, defecation/watery diarrhea, and visceral hyperalgesia). Conversely, selective CRF₁ antagonists or CRF₁/CRF₂ antagonists, abolished or reduced exogenous CRF and stress-induced stimulation of colonic motility, defecation, diarrhea and colonic mast cell activation and visceral hyperalgesia to colorectal distention. By contrast, the CRF₂ signaling in the colon dampened the CRF₁ mediated stimulation of colonic motor function and visceral hyperalgesia. These data provide a conceptual framework that sustained activation of the CRF₁ system at central and/or peripheral sites may be one of the underlying basis of IBS-diarrhea symptoms. While targeting these mechanisms by CRF₁ antagonists provided a relevant novel therapeutic venue, so far these promising preclinical data have not translated into therapeutic use of CRF₁ antagonists. Whether the existing or newly developed CRF₁ antagonists will progress to therapeutic benefits for stress-sensitive diseases including IBS for a subset of patients is still a work in progress.

Effect of venlafaxine on experimental colitis in normal and reserpinised depressed rats

Psychological disorders such as depression have more prevalence in inflammatory bowel disease patients and can exacerbate the clinical course of the disease, so anti-depressant therapy may have a potential to positively impact the disease course. On the other hand several antidepressant drugs have shown anti-inflammatory and immunomodulatory properties. Thus, this study aimed to explore the beneficial effects of venlafaxine on experimental colitis in normal and reserpinised depressed rats. Acetic acid colitis was induced in both reserpinised and non-reserpinised rats. Reserpinised groups received reserpine at dose of 6 mg/kg i.p.1 h prior to colitis induction and then treated with venlafaxine at doses of 10, 20, 40 mg/kg given i.p. 2 h after induction of colitis and daily for 4 consecutive days. Non-reserpinised groups treated with 10, 20, 40 mg/kg venlafaxine i.p. 2 h after the induction of colitis and daily for 4 successive days. Dexamethasone (1 mg/kg, i.p.) was used as reference drug. Colonic inflammation was evaluated using macroscopic, histological and myeloperoxidase activity measurements. Results showed that reserpine at dose of 6 mg/kg exacerbated the colitis damage. Compared to acetic acid control, venlafaxine at dose of 40 mg/kg as well as dexamethasone significantly improved colitis parameters in both reserpinised and non-reserpinised animals. Venlafaxine reduced inflammatory injury in this animal model of induced ulcerative colitis. These effects are probably mediated first through depressive behavioral changes that could be mediated through the brain-gut axis and second for the anti-inflammatory effect of the drug.

The brain-gut axis in health and disease

The interaction between the brain and the gut has been recognized for many centuries. This bidirectional interaction occurs via neural, immunological and hormonal routes, and is important not only in normal gastrointestinal function but also plays a significant role in shaping higher cognitive function such as our feelings and our subconscious decision-making. Therefore, it remains unsurprising that perturbations in normal signalling have been associated with a multitude of disorders, including inflammatory and functional gastrointestinal disorders, and eating disorders.

Beneficial Effects of Maprotiline in a Murine Model of Colitis in Normal and Reserpinised Depressed Rats

Background. Anti-inflammatory and immunomodulatory activities have been reported for maprotiline, a strong norepinephrine reuptake inhibitor. In addition, some other antidepressant drugs have shown beneficial effects in experimental colitis. Methods. All the animals were divided into normal and depressed groups. In normal rats colitis was induced by instillation of 2 mL of 4% acetic acid and after 2 hours, maprotiline (10, 20, and 40 mg/kg, i.p.) was administered. In reserpinised depressed rats, depression was induced by injection of reserpine (6 mg/kg, i.p.), 1 h prior to colitis induction, and then treated with maprotiline (10, 20, and 40 mg/kg). Treatment continued daily for four days. Dexamethasone (1 mg/kg, i.p.) was given as a reference drug. On day five following colitis induction, animals were euthanized and distal colons were assessed macroscopically, histologically, and biochemically (assessment of myeloperoxidase activity). Results. Maprotiline significantly improved macroscopic and histologic scores and diminished myeloperoxidase activity in both normal and depressed rats while reserpine exacerbated the colonic damage. Conclusion. Our data suggests that the salutary effects of maprotiline on acetic acid colitis are probably mediated first through depressive behavioral changes that could be mediated through the brain-gut axis and second for the anti-inflammatory effect of the drug.

Correlation between depression, anxiety, and polymorphonuclear cells' resilience in ulcerative colitis: the mediating role of heat shock protein 70

Background

To investigate whether anxiety and depression levels are associated with Heat Shock Protein 70 (HSP70) induction in the colon of patients with ulcerative colitis (UC).

Methods

The design was cross-sectional. Clinical activity was assessed by the Rachmilewitz Index (CAI). Three psychometric questionnaires were used: Zung Depression Rating Scale (ZDRS), Spielberg State-Trait Anxiety Inventory (STAI), Hospital Anxiety and Depression Scale (HADS). Colon biopsies were obtained from each affected anatomical site. Severity of inflammation was assessed by eosin/hematoxylin. Constitutive (HSP70c) and inducible (HSP70i) HSP70 expression were immunohistochemically studied.

Results

29 UC patients were enrolled (69% men). Mean age was 46.5 years (SD: 19.5). Inflammation severity was moderate in 17 patients, severe in 6, and mild in 6. The mean number of years since diagnosis was 7.9 (SD: 6.5). The mean CAI was 6.4 (SD: 3.1). In active UC, there was downregulation of HSP70c in inflamed epithelium, without significant HSP70 induction. In 22/29 cases of active cryptitis, polymorphonuclear cells (PMN) clearly expressed HSP70i, with weak, focal positivity in the other 7 cases. Except for the hospital anxiety scale, scores in all psychometric tools were higher in patients with strong HSP70i immunoreactivity in the PMN. Logistic regression showed a strong positive relationship between HSP70i immunoreactivity in the PMN cells and scores in the trait anxiety, ZDRS, and hospital depression scales, (Odds ratios 1.3, 1.3, and 1.5; P = 0.018, 0.023, and 0.038; Wald test, 5.6, 5.2, and 4.3 respectively) and a weaker but significant positive correlation with the CAI (Odds ratio 1.654; P = 0.049; Wald test 3.858).

Conclusion

HSP70 is induced in PMN cells of UC patients and its induction correlates with depression and anxiety levels.

Psychological factors and stress in inflammatory bowel disease

The role of psychological distress and personality as predisposing factors for the development of inflammatory bowel disease (IBD) remains controversial. Attempts to investigate the role of psychological factors in IBD exhibited rather conflicting results. Among the studies concerning the effects of stress or depression on the course of IBD, the majority suggest that stress worsened IBD, the rest giving either negative or inconclusive results. However, application of strategies, including avoidance of coping and training patients in problem solving or emotion-oriented, could influence the course of IBD. Large controlled clinical trials are needed in order to clarify the impact of psychological interventions on the quality of life and the course of disease.

Neuropeptide Y, peptide YY and pancreatic polypeptide in the gut-brain axis

The gut-brain axis refers to the bidirectional communication between the gut and the brain. Four information carriers (vagal and spinal afferent neurons, immune mediators such as cytokines, gut hormones and gut microbiota-derived signalling molecules) transmit information from the gut to the brain, while autonomic neurons and neuroendocrine factors carry outputs from the brain to the gut. The members of the neuropeptide Y (NPY) family of biologically active peptides, NPY, peptide YY (PYY) and pancreatic polypeptide (PP), are expressed by cell systems at distinct levels of the gut-brain axis. PYY and PP are exclusively expressed by endocrine cells of the digestive system, whereas NPY is found at all levels of the gut-brain and brain-gut axis. The major systems expressing NPY comprise enteric neurons, primary afferent neurons, several neuronal pathways throughout the brain and sympathetic neurons. In the digestive tract, NPY and PYY inhibit gastrointestinal motility and electrolyte secretion and in this way modify the input to the brain. PYY is also influenced by the intestinal microbiota, and NPY exerts, via stimulation of Y1 receptors, a proinflammatory action. Furthermore, the NPY system protects against distinct behavioural disturbances caused by peripheral immune challenge, ameliorating the acute sickness response and preventing long-term depression. At the level of the afferent system, NPY inhibits nociceptive input from the periphery to the spinal cord and brainstem. In the brain, NPY and its receptors (Y1, Y2, Y4, Y5) play important roles in regulating food intake, energy homeostasis, anxiety, mood and stress resilience. In addition, PP and PYY signal to the brain to attenuate food intake, anxiety and depression-related behaviour. These findings underscore the important role of the NPY-Y receptor system at several levels of the gut-brain axis in which NPY, PYY and PP operate both as neural and endocrine messengers.

An integrated model of care for inflammatory bowel disease sufferers in Australia: development and the effects of its implementation

BACKGROUND

Psychological comorbidities are associated with poor outcome and increased healthcare utilization in patients with inflammatory bowel disease (IBD). However, a model of care addressing the biopsychosocial dimension of disease is not routinely applied in IBD. This review describes the development of such a model and the effects of its implementation in a hospital-based cohort of patients with IBD.

METHODS

Three different approaches were used: 1) collecting baseline epidemiological data on mental health comorbidities; 2) raising awareness of and targeting mental health problems; 3) examining the effects of the model implementation.

RESULTS

High rates of anxiety and depressive symptoms (36% and 13%, respectively) that are maintained over time were identified in IBD patients presenting at a metropolitan teaching hospital. Patients with documented psychological comorbidities were more likely to be hospitalized than those without (odds ratio [OR] = 4.13, 95% confidence interval [CI]: 1.25, 13.61). Improvements in disease activity, anxiety, depression, quality of life, and coping have been noted when cognitive-behavioral therapy (CBT) was provided to patients. A drop in the use of opiates (P = 0.037) and hospitalization rates (from 48% to 30%) in IBD patients has been noted as a result of introduction of the changed model of care. In addition, the mean total cost of inpatient care was lower for IBD patients than controls (US$12,857.48 [US$15,236.79] vs. US$ 30,467.78 [US$ 53,760.20], P = 0.005).

CONCLUSION

Our data to date suggest that an integrated model of care for patients with IBD may yield superior long-term outcomes in terms of medication use and hospitalization rates and reduce healthcare costs.

Psychological issues in inflammatory bowel disease: an overview

Inflammatory bowel disease (IBD) including Crohn's disease (CD) and ulcerative colitis (UC) is a chronic and disabling disease with unknown etiology. There have been some controversies regarding the role of psychological factors in the course of IBD. The purpose of this paper is to review that role. First the evidence on role of stress is reviewed focusing on perceived stress and patients' beliefs about it in triggering or exacerbating the course of IBD. The possible mechanisms by which stress could be translated into IBD symptoms, including changes in motor, sensory and secretory gastrointestinal function, increase intestinal permeability, and changes in the immune system are, then reviewed. The role of patients' concerns about psychological distress and their adjustment to disease, poor coping strategies, and some personality traits that are commonly associated with these diseases are introduced. The prevalence rate, the timing of onset, and the impact of anxiety and depression on health-related quality of life are then reviewed. Finally issues about illness behavior and the necessity of integrating psychological interventions with conventional treatment protocols are explained.

Gut feelings: the emerging biology of gut-brain communication

The concept that the gut and the brain are closely connected, and that this interaction plays an important part not only in gastrointestinal function but also in certain feeling states and in intuitive decision making, is deeply rooted in our language. Recent neurobiological insights into this gut-brain crosstalk have revealed a complex, bidirectional communication system that not only ensures the proper maintenance of gastrointestinal homeostasis and digestion but is likely to have multiple effects on affect, motivation and higher cognitive functions, including intuitive decision making. Moreover, disturbances of this system have been implicated in a wide range of disorders, including functional and inflammatory gastrointestinal disorders, obesity and eating disorders.