Brain-gut Interactions Research Articles

Disorders of gut-brain interaction, eating disorders and gastroparesis: a call for coordinated care and guidelines on nutrition support.

Disorders of gut-brain interaction, eating disorders and gastroparesis: a call for coordinated care and guidelines on nutrition support.

The Role of the Gut Microbiota in Individuals with Irritable Bowel Syndrome: A Scoping Review.

Irritable bowel syndrome (IBS) represents the most prevalent disorder of brain-gut interaction, affecting approximately 10% of the global population. The objective of this study was to examine the mechanisms by which the gut microbiota contributes to the development of IBS. To this end, a review of articles that examined the gut microbiota of IBS patients was conducted. A search was conducted using PubMed and J-STAGE for articles published over the past five years that relate to the gut microbiota in patients with IBS. Individuals diagnosed with IBS display a reduction in alpha diversity and a decline in butyrate-producing bacteria, which collectively indicate a state of dysbiosis within their gut microbiota. Butyrate plays a dual role in the body, acting as a source of nutrition for the intestinal epithelium while also regulating the expression of dopamine transporters and D2 receptors in the central nervous system through epigenetic mechanisms. These characteristics may be linked to dysfunction of the central dopamine D2 pathway and play a role in the formation of various symptoms in IBS.

The value of differential diagnosis of post-reflux swallow-induced peristaltic wave index between esophageal diseases of gut-brain interaction and gastroesophageal reflux disease

Objective: To analyze the value of differential diagnosis of post-reflux swallow-induced peristaltic wave index (PSPWI) between esophageal diseases of gut-brain interaction (E-DGBI) and gastroesophageal reflux disease (GERD). Methods: The patients diagnosed as E-DGBI and GERD in the Department of Gastroenterology, Beijing Tsinghua Changguang Hospital from June 2016 to June 2018 were retrospectively included. The medical records, gastroscopy and 24-hour pH-intraluminal impedance monitoring reports were collected. According to clinical diagnosis, the patients were divided into E-DGBI group and GERD group. PSPWI, acid exposure time (AET), DeMeester score, total reflux times and mean nocturnal baseline impedance (MNBI) were compared between the both group. The receiver operating characteristic curve (ROC) of PSPWI, AET, total reflux times and MNBI was drawn to identify the sensitivity and specificity of E-DGBI and GERD. The cut-off values were calculated with Youden index and the area under the curve (AUC) was compared. Results: A total of 73 patients were included,including 36 males and 37 females, whose age [M (Q1, Q3)] was 54.0 (42.6, 63.0) years. There were 39 cases in E-DGBI group and 34 cases in GERD group. The 24-h AET [0.5 (0.1, 1.6) vs 6.0 (3.6, 11.9)], DeMeester score [2.8 (1.1, 5.7) vs 20.4 (14.7, 47.4) score] and total reflux times [32.0 (19.0, 53.0) vs 66.0 (34.3, 96.0) times] were significantly higher in E-DGBI group than those in GERD group (all P<0.001);MNBI in E-DGBI group was higher than that in GERD group[2 375.0 (1 726.0, 2 978.0)Ω vs 1 361.0 (814.0, 2 273.5)Ω, P<0.001]. The PSPWI in E-DGBI group is higher than that in GERD (0.56±0.19 vs 0.25±0.15, P<0.001). According to ROC, with PSPWI>0.46 as the cut-off value, the AUC was 0.895 (95%CI: 0.827-0.963) in differentiating E-DGBI and GERD. The sensitivity was 94.1% and the specificity was 69.2%. There were no significant differences of AUC between PSPWI and AET or total reflux events (all P>0.05). But the AUC of PSPWI was higher than that of MNBI (AUC=0.749,95%CI:0.632-0.866,P=0.031). Conclusion: PSPWI can better distinguish E-DGBI from GERD.

A Review of Pharmacologic and Non-Pharmacologic Therapies in the Management of Irritable Bowel Syndrome: Current Recommendations and Evidence.

Irritable bowel syndrome (IBS) is a highly prevalent and debilitating disorder of gut-brain interaction (DGBI) affecting millions globally. It imposes a significant burden on healthcare systems and is a leading cause of workplace absenteeism. IBS is classified into several subtypes based on predominant presenting symptoms, including IBS with constipation (IBS-C) and IBS with diarrhea (IBS-D), with each requiring targeted approaches to treatment. Some treatments, such as psychotherapy, dietary intervention, and medications like tricyclic antidepressants, are nonspecific and recommended for managing IBS symptoms across all subtypes. In contrast, therapies like secretagogues for IBS-C and eluxadoline or rifaximin for IBS-D are subtype-specific. However, many IBS treatments carry conditional recommendations and are based on low-certainty evidence, emphasizing the need for further research to expand the available treatment options. This review compares the latest IBS management guidelines from the American Gastroenterological Association (AGA), American College of Gastroenterology (ACG), British Society of Gastroenterology (BSG), and European Society for Neurogastroenterology and Motility (ESNM). Pharmacologic and non-pharmacologic therapies, including established and emerging interventions, will be explored to provide a comprehensive guide to management.

Altered parasympathetic outflow and central sensitization response to continuous pain in cyclic vomiting syndrome: a functional magnetic resonance imaging study.

Cyclic vomiting syndrome (CVS) is a disorder of brain-gut interaction characterized by recurrent episodes of nausea and vomiting interspersed with asymptomatic periods and associated with autonomic nervous system dysfunction. We examined the dysautonomic response to noxious stimuli seen in CVS patients using our previously validated approach to integrate peripheral autonomic outflow metrics, temporal summation of pain, and brain fMRI. BOLD fMRI and ECG were acquired from CVS patients and healthy adults during a rest condition and a sustained cuff pressure pain stimulus at the leg. After the latter scan, participants rated pain for the full 6-minute pain stimulus as well as first, middle, and last two-minutes to calculate temporal summation. During sustained pain, patients (n=13) exhibited greater reduction in heart rate variability within the high-frequency range (HF-HRV) and reduced anticorrelation between HF-HRV and fMRI signal in the anterior insula, pregenual anterior cingulate cortex, and ventrolateral and dorsolateral prefrontal cortex relative to healthy adults (n=13). Compared to healthy adults (n=14), patients (n=14) exhibited increasing pain intensity over the course of sustained cuff pressure. Seed-based functional connectivity analysis revealed for healthy adults (n=13), pain sensitization correlated with pain-induced increases in connectivity between primary somatosensory cortex and regions of interest in both left anterior insula/posterior orbitofrontal cortex and right pre-supplementary motor area, while this correlation was disrupted in CVS (n=10). Our results support altered central coding of nociceptive stimuli and autonomic responsivity of CVS patients in key brain regions implicated in autonomic control and interoception.

A machine learning approach to stratify patients with hypermobile Ehlers-Danlos syndrome/hypermobility spectrum disorders according to disorders of gut brain interaction, comorbidities and quality of life.

A high prevalence of disorders of gut-brain interaction (DGBI) exist in patients with hypermobile Ehlers-Danlos Syndrome (hEDS) and hypermobility spectrum disorders (HSD). However, it is unknown if clusters of hEDS/HSD patients exist which overlap with different DGBIs and whether this overlap influences presence of comorbidities and quality of life. We aimed to study these knowledge gaps. A prospectively collected hEDS/HSD cohort of 1044 individuals were studied. We undertook Uniform Manifold Approximation and Projection-enabled (UMAP) dimension reduction to create a representation of nonlinear interactions between hEDS/HSD and DGBIs, from which individuals were stratified into clusters. Somatization, Postural Tachycardia Syndrome (PoTS), autonomic symptoms, psychological factors and quality of life were statistically compared between clusters. The mean age of patients was 40 ± 13.2 years; 87.8% were female. Patients segregated into three clusters: Cluster 0 (n = 466): hEDS/HSD+ functional foregut disorders (FFD) + irritable bowel syndrome (IBS); Cluster 1 (n = 180): hEDS/HSD+ IBS and Cluster 2 (n = 337): hEDS/HSD alone. In cluster 0, we demonstrated increased somatization (p <0.0001), anxiety (p <0.0001), depression (p <0.0001), PoTS prevalence (p = 0.003), autonomic symptoms (p <0.0001) and reduced quality of life (p <0.0001) compared to cluster 2. Cluster 0 had greater comorbidity burden than cluster 1. Within hEDS/HSD, subgroups exist with a high prevalence of FFD and IBS. These subgroups have a higher prevalence of psychological disorders, dysautonomia and poorer quality of life compared with hEDS/HSD alone. Further research should focus on healthcare utilization, management and prognosis in hEDS/HSD and DGBI overlap.

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.

Abnormal Autonomic Nervous Regulation in Patients with Globus Pharyngeus.

Globus pharyngeus could be described as a benign sensation of lump or foreign object in the throat. The etiology of the globus as a solitary syndrome is still unknown, but it is proposed that stress could have an important role in symptom emergence. To evaluate the autonomic nervous regulation in patients with globus compared to healthy controls in reaction to stress. Patients included in the study were diagnosed based on ROME IV criteria for Disorders of Gut Brain Interaction. Besides globus, the patients did not suffer any other substantial medical condition. As a control group, measurement of healthy volunteers was performed. Both groups underwent the same stress protocol assessment in the same laboratory settings. The protocol consist of two types of stressors: cold pressor test and mental arithmetic test to test different types of autonomic reactivity. Baroreflex sensitivity was significantly decreased in patients compared to controls in all phases of the protocol. Low-frequency band of systolic blood pressure variability was significantly increasedduring both stress phases in patients compared to controls. High-frequency band of heart rate variability was significantly decreased in patients compared to controls during the both of the stress phases. The results of this study shows discrete abnormalities in complex autonomic reflex control which are predominantly manifested in response to stressful stimuli indicating altered neurocardiac regulation as a reaction to stress associated with globus pharynegus. This fact could have an important role in the personalized management of globus patients such as biofeedback.

Prevalence of functional diarrhea in children and adolescents.

Functional diarrhea (FDr) is a common disorder in toddlers and adults. In children, the Rome criteria define FDr as a disorder of children younger than 5 years old exclusively. However, in clinical practice, school-aged children and adolescents sometimes consult for symptoms that mimic the diagnosis of FDr. We conducted a study aimed at assessing the prevalence of FDr in school-aged children and adolescents. A cross-sectional study was conducted in children aged 8-18 years from two schools in Colombia. Children completed self-report validated questionnaires to diagnose disorders of gut-brain interaction (DGBI) per Rome IV (QPGS-IV) for their age group and the questions related to FDr from the Rome IV questionnaire for infants and toddlers. After excluding children with organic diseases and IBS-D, 981 participants were included (female 53.8%, White 24.7%, Indigenous 10.9%, mixed race 52.6%). Of the 981 participants, 325 (33.1%) had a DGBI. Of these, 17 children (5.2%) were diagnosed with FDr (3 participants 8-12 years; 14 participants 13-18 years). FDr was more prevalent among White children compared to non-White children (mixed race, Black, and Indigenous) (p = 0.01). Despite the absence of FDr in the Rome IV criteria for children and adolescents, 1.7% of children aged 8-18 years likely have FDr. This study suggests that FDr does occur in children and adolescents. If confirmed in future studies, the diagnosis of FDr should be considered for inclusion in future editions of the Rome criteria for children of all ages.

Diagnostic classification systems for disorders of gut-brain interaction should include psychological symptoms.

The group of disorders known as Disorders of Gut Brain Interaction (DGBI) were originally labeled functional GI disorders and were thought to be disorders of the gastrointestinal tract that had several psychological conditions as comorbidities. Despite mounting evidence that psychological morbidity plays an innate role in the etiology and maintenance of DGBI, none of the Rome IV criteria include any measure of psychological symptoms. This study tested the hypothesis that individuals would cluster differently if GI symptoms alone were considered versus GI symptoms combined with measures of psychological symptoms. Data were obtained from the Rome Foundation Global Epidemiology Study measuring Rome IV GI symptoms, psychological measures and demographic characteristics. Latent profile models were used to cluster individuals based on (i) GI symptoms only (GI only) and then (ii) GI and psychological measures (GI + Psych). Individuals clustering into the same group of individuals whether formed via GI only or GI + Psych, ranged from 96% for a 2-class solution (the most simplistic) to 76% with 6 classes (the parsimonious system) and 59% with twenty-two classes (mimicking Rome IV). The generalisability of this finding between six geographic regions was confirmed with agreement varying between 95%-97% for 2 clusters and 71-79% for 6 classes and 51%-63% for 22 classes. These findings were also consistent between DGBI (range 94% with 2 classes to 50% with 22 classes) and non-DGBI (range 97% with 2 clusters to 65% with 22 classes) groups. Our data suggest that considering psychological as well as gastrointestinal symptoms would lead to a different clustering of individuals in more complex, and accurate, classification systems. For this reason, future work on DGBI classification should consider inclusion of psychological traits.

Association Between Irritable Bowel Syndrome and Lower Urinary Tract Symptomatology: A Cross-sectional Study in Mexican Population.

This study aimed to investigate the clinical phenotype of urinary symptoms in patients diagnosed with irritable bowel syndrome, the factors associated with this overlap, and the impact of urinary symptoms on their quality of life. Irritable bowel syndrome is a common disorder, affecting up to 3.8% of the population. The overlap with other disorders of the gut-brain interaction, psychiatric disorders, and other somatic disorders is common. Moreover, the association between irritable bowel syndrome and urinary symptoms has been recognized, but the clinical phenotype remains unclear. This cross-sectional study involved patients with irritable bowel syndrome according to Rome IV. Lower urinary tract symptoms were classified using the International Continence Society's classification. Data on demographics, medical history, medication use, anxiety, depression, and quality of life were collected and analyzed using logistic regression analysis. The study included 428 subjects, 86 diagnosed with irritable bowel syndrome. Patients exhibited a higher prevalence of lower urinary tract symptoms (60.5%, 95% CI: 50.5-71.9). Multivariate analysis revealed associations between irritable bowel syndrome and lower urinary tract symptoms (OR: 2.49, 95% CI: 1.48-4.18, P=0.001), particularly storage urinary symptoms (OR: 1.94, 95% CI: 1.10-3.40, P=0.021). Patients with urinary symptoms reported significantly lower quality of life compared with those without these symptoms (50.8±17.2 vs. 76.7±21.8, P<0.001). Irritable bowel syndrome is associated with lower urinary tract symptoms, contributing to a significant reduction in quality of life. Clinicians should consider referring patients with irritable bowel syndrome and lower urinary tract symptoms to experts in urodynamics to provide targeted management.

Gastrointestinal, Behaviour and Anxiety Outcomes in Autistic Children Following an Open Label, Randomised Pilot Study of Synbiotics vs Synbiotics and Gut-Directed Hypnotherapy.

Alterations of the microbiome-gut-brain (MGB) axis have been associated with autism spectrum disorder (ASD) and disorders of gut-brain interaction (DGBI). DGBI are highly prevalent in autistic children and are associated with worsening behaviour and anxiety. Treatments such as probiotics, prebiotics and gut-directed hypnotherapy (GDH) have shown efficacy in improving gut symptoms in children. The primary objective of the study was to compare changes in gastrointestinal (GI) scores following a 12-week intervention of synbiotics (prebiotic + probiotic) +/- GDH with a follow-up at 24 weeks. Secondary objectives included changes in behavioural and anxiety symptoms, while changes in gut microbiome composition were assessed as an exploratory objective. Children diagnosed with ASD aged 5.00-10.99 years (n = 40) were recruited and randomised (1:1) to a 12-week intervention of either synbiotics (SYN group) or synbiotics + GDH (COM group). Both the SYN and COM group experienced significant reductions in total GI scores post-intervention and at follow-up (p < 0.001), with no superiority of the COM treatment over the SYN treatment. The COM group showed beneficial reductions in anxiety scores (p = 0.002) and irritability behaviours (p < 0.001) which were not present in the SYN group. At follow-up, only those in the COM group maintained significant reductions in GI pain scores (p < 0.001). There were significant changes in gut microbiota such as increases in Bifidobacterium animalis and Dialister in both groups over time. In conclusion,synbiotics with or without GDH may help support standard care for autistic children who suffer comorbid DGBI. The trial was prospectively registered at clinicialtrials.gov on 16 November 2020 (NCTO4639141).

Gut-Brain Axis and Psychopathology: Exploring the Impact of Diet with a Focus on the Low-FODMAP Approach.

The gut-brain axis (GBA) is a bidirectional communication network connecting the central nervous system with the gastrointestinal (GI) tract, influencing both mental and physical health. Recent research has underscored the significant role of diet in modulating this axis, with attention to how specific dietary patterns can impact anxiety and depression, particularly when linked to disorders of gut-brain interaction (DGBIs), like intestinal bowel syndrome (IBS). This narrative review examines the effects of specific diet regimens on the GBA and its potential role in managing psychopathology, focusing on anxiety and depression, IBS, and the low-FODMAP diet. We conducted a search on PubMed and MEDLINE by combining the following key terms: "Gut-Brain Axis", "Irritable Bowel Syndrome", "Low FODMAP diet", "Mediterranean Diet", "Psychopathology", "Anxiety and Depression", and "Gut Microbiota". We applied the following filters: "Clinical Trials", "Randomized Controlled Trials", "Reviews", "Meta-Analyses", and "Systematic Reviews". In total, 59 papers were included. Low-FODMAP diet, originally developed to alleviate GI symptoms in IBS, may also positively influence mental health by modulating the GBA and improving the gut microbiota (GM) composition. New insights suggest that combining the low-FODMAP diet with the Mediterranean diet could offer a synergistic effect, enhancing both GI and psychological therapeutic outcomes. Understanding the complex interactions between diet, the GM, and mental health opens new avenues for holistic approaches to managing psychopathology, particularly when linked to GI symptoms.

From microbes to mind: germ-free models in neuropsychiatric research.

The gut-microbiota-brain axis refers to the bidirectional communication system between the gut, its microbial community, and the brain. This interaction involves a complex interplay of neural pathways, chemical transmitters, and immunological mechanisms. Germ-free animal models have been extensively employed to investigate gut-microbiota-brain interactions, significantly contributing to our current understanding of the role of intestinal microbes in brain function. However, despite the many benefits, this absence of microbiota is not futile. Germ-free animals present physiological and neurodevelopmental alterations that can persist even after reconstitution with normal microbiota. Therefore, the main goal of this minireview is to discuss how some of the inherent limitations of this model can interfere with the conclusion obtained when using these animals to study the complex nature of neuropsychiatric disorders. Furthermore, we examine the inclusion and use of antibiotic-based treatments as an alternative in the research of gut-brain interactions.

The Diagnosis and Management of Chronic Constipation in Italy: Results from a Survey Conducted among Italian Gastroenterologists.

Background: Chronic constipation (CC) is one of the most common disorders of gut-brain interaction (DGBI). The management of CC requires specific skills due to its complex and multifactorial pathophysiology and its multistep treatment. The aims of this study were to evaluate the availability and the use of diagnostic tools for CC in Italy and the therapeutic management of CC by Italian gastroenterologists (GEs). Methods: A survey was conducted during the 28th meeting of the Italian Federation of Digestive Disease Societies (FISMAD; Rome, Italy, 11-14 May 2022). The survey explored the presence of a clinic dedicated to DGBIs, the availability and the use of specific diagnostic tools, the routine use of digital rectal examination (DRE), and the therapeutic approach to CC by Italian GEs. Results: The survey was taken by 236 GEs. The most significant results were that 42% of respondents had a clinic dedicated to DGBI in their institute; DRE was regularly performed by 56.8% of GEs when evaluating a CC patient; young GEs (≤40 years) performed DRE less frequently than older ones (p < 0.001); anorectal manometry was available to 44.3% of GEs; balloon expulsion test (BET) was available to 19.1% of GEs; GEs with a clinic dedicated to DGBI had more frequent access to anorectal physiology testing (p < 0.001); diet and lifestyle advice were the most frequently prescribed treatments; and fiber and macrogol were the second and third most prescribed treatments, respectively. Conclusions: The survey provides an interesting picture of CC management by Italian GEs. The results are in line with previous data collected about 10 years ago among Italian GEs ("CHRO.CO.DI.T.E study"); DRE is still rarely performed by Italian GEs (particularly by young GEs). The availability of anorectal physiology testing is still limited, and BET, which could be easily performed in everyday clinical settings, is rarely performed. Lifestyle suggestions, macrogol and fiber are the preferred treatment, as recommended by all guidelines. These results will be useful to identify as yet unmet educational needs and critical issues to improve CC management.

New Role of the Serotonin as a Biomarker of Gut-Brain Interaction.

Serotonin (5-hydroxytryptamine: 5-HT), a neurotransmitter that regulates mood in the brain and signaling in the gut, has receptors throughout the body that serve various functions, especially in the gut and brain. Selective serotonin reuptake inhibitors (SSRIs) are used to treat depression, but their efficacy is uncertain. Depression is often associated with early gastrointestinal symptoms. Gut disorders such as functional dyspepsia (FD), irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are linked to elevated serotonin levels. In this review, we would like to discuss the approach of using serotonin as a biomarker for gut-brain, and body-wide organ communication may lead to the development of preventive and innovative treatments for gut-brain disorders, offering improved visibility and therapeutic monitoring. It could also be used to gauge stress intensity for self-care and mental health improvement.

Symptom bothersomeness and life interference support Rome clinical criteria as clinically relevant indicators of DGBI.

Irritable bowel syndrome (IBS) and functional dyspepsia (FD) are common disorders of gut-brain interaction (DGBI). The Rome IV criteria are the gold standard for research when diagnosing DGBI. However, bothersomeness, or the degree to which symptoms are distressing or disruptive to a person's daily life, is a potential treatment-seeking motivator that is not assessed by the Rome criteria. The Rome Foundation developed and published diagnostic criteria for clinical practice that include bothersomeness. We aimed to evaluate these constructs via patient focus groups to determine what prompts healthcare-seeking as a means to assess its value in the Rome clinical criteria. Adults meeting Rome IV criteria for IBS, FD, or both participated in focus groups in Australia and the United States. Semi-structured interview transcripts were analyzed using Template Thematic Analysis, with three a priori and other a posteriori themes refined iteratively through team discussion and consensus. Participants confirmed the frequency and duration of symptoms was not sufficient to reflect illness experience. Four major themes emerged: (1) Bothersomeness should be included in assessments of IBS and FD; (2) Patients find many DGBI symptoms bothersome; (3) Bothersomeness traverses multiple domains of quality of life; (4) Patients may hesitate to seek medical advice due to past negative experiences. These findings support the value of the Rome Clinical Criteria. They emphasize the importance of expanding assessments of patients with DGBI to include how bothersome they perceive symptoms to be, how much symptoms interfere with their daily life, and what may moderate their decisions to seek treatment.

Exploring cyclic vomiting syndrome (CVS) worldwide: Current epidemiological insights and recent developments.

Cyclic vomiting syndrome (CVS), a disorder of gut-brain interaction, presents with recurrent episodes of severe nausea and vomiting. It is often associated with missed or delayed diagnoses and substantial healthcare utilization. Despite historical recognition dating back to the 19th century, epidemiological insights remain limited, with research predominantly originating from specific regions, such as the US. CVS prevalence and incidence rates vary widely and are hindered by inconsistent methodologies and disease recognition. This review aims to provide a comprehensive overview of CVS prevalence and incidence rates. It reviews the currently available data and identifies gaps in knowledge. Understanding the global epidemiology of CVS, increasing awareness of the disease, and fostering global collaboration are crucial. Other pertinent issues include disparities in outcomes, particularly among African Americans and Hispanics in the United States, underscoring the need to understand the social determinants of health that drive disease outcomes. This understanding can inform targeted interventions to address these barriers and achieve equitable healthcare both in the United States and globally.

From Microbes to Myocardium: A Comprehensive Review of the Impact of the Gut-Brain Axis on Cardiovascular Disease.

Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality worldwide despite advances in medical research and therapeutics. Emerging evidence suggests a significant role of the gut-brain axis, a complex communication network involving the gut microbiota, central nervous system, and cardiovascular system, in modulating cardiovascular health. The gut microbiota influences systemic inflammation, neurohumoral pathways, and metabolic processes, which are critical in the pathogenesis of CVD. Dysbiosis, or an imbalance in the gut microbiota, has been implicated in various cardiovascular conditions, including hypertension, atherosclerosis, and heart failure. This comprehensive review aims to elucidate the intricate relationship between the gut microbiome, brain, and cardiovascular system, highlighting the mechanisms by which gut-derived signals affect cardiovascular function. Key microbial metabolites, such as short-chain fatty acids (SCFAs) and trimethylamine N-oxide (TMAO), and their impact on vascular health and blood pressure regulation are discussed. Furthermore, the review explores potential therapeutic strategies targeting the gut-brain axis, including probiotics, prebiotics, dietary modifications, and pharmacological interventions, to improve cardiovascular outcomes. Despite promising findings, the field faces challenges such as individual variability in microbiome composition, complexities in gut-brain interactions, and the need for robust clinical trials to establish causality. Addressing these challenges through interdisciplinary research could pave the way for innovative, personalized therapeutic approaches. This review provides a comprehensive understanding of the gut-brain-cardiovascular axis, underscoring its potential as a novel target for preventing and treating CVD.

Review article: The role of the gut-brain axis in inflammatory bowel disease and its therapeutic implications.

Treatments targeting the gut-brain axis (GBA) are effective at reducing symptom burden in irritable bowel syndrome (IBS). The prevalence of common mental disorders and IBS-type symptom reporting is significantly higher in inflammatory bowel disease (IBD) than would be expected, suggesting potential GBA effects in this setting. Manipulation of the GBA may offer novel treatment strategies in selected patients with IBD. We present a narrative review of the bi-directional effects of the GBA in IBD and explore the potential for GBA-targeted therapies in this setting. We searched MEDLINE, EMBASE, EMBASE Classic, PsychINFO, and the Cochrane Central Register of Controlled Trials for relevant articles published by March 2024. The bi-directional relationship between psychological well-being and adverse longitudinal disease activity outcomes, and the high prevalence of IBS-type symptom reporting highlight the presence of GBA-mediated effects in IBD. Treatments targeting gut-brain interactions including brain-gut behavioural treatments, neuromodulators, and dietary interventions appear to be useful adjunctive treatments in a subset of patients. Psychological morbidity is prevalent in patients with IBD. The relationship between longitudinal disease activity outcomes, IBS-type symptom reporting, and poor psychological health is mediated via the GBA. Proactive management of psychological health should be integrated into routine care. Further clinical trials of GBA-targeted therapies, conducted in selected groups of patients with co-existent common mental disorders, or those who report IBS-type symptoms, are required to inform effective integrated models of care in the future.