Psychological stress and corticotropin-releasing hormone increase intestinal permeability in humans by a mast cell-dependent mechanism

Fire in the belly: Stress and antibiotics induce dysbiosis and inflammation in the gut of common carp

Fish are exposed to numerous stressors which negatively affect their immune response and increase infection susceptibility. The risk of bacterial infections results in the excessive and preventive use of antibiotics. Therefore, we aimed to study how antibiotic treatment and restraint stress will affect the stress response, microbiota composition, gut morphology, and inflammatory reaction in common carp. Both restraint stress and antibiotic treatment increased cortisol level. Moreover, antibiotics induced dysbiosis in fish gut, manifested by a decrease in the total abundance of bacteria, and a shift in bacteria diversity, including a reduced number of Aeromonas, Bacteroides, Barnesiellaceae, Cetobacterium and Shewanella and an increased abundance of Flavobacterium. To a lesser extent, stress modified gut microbiota, as it decreased bacteria number and slightly changed the microbiota composition by decreasing Cetobacterium abundance and increasing Vibrio abundance. Microbiota of the antibiotic-treated and stressed fish shifted from the beneficial bacterial genera - Cetobacterium and Bacteroides, to the increased presence of unfavorable bacteria such as Brevinema, Flavobacterium and Desulfovibrionaceae. Stress and antibiotic-induced changes in the gut microbiota were related to the changes in the gut morphology when the higher abundance of goblet and rodlet cells and increased secretion activity of goblet cells were observed. Moreover, up-regulation of the expression of genes encoding pro-inflammatory mediators and cytokines involved in the Th17 immune response was present in the gut of the antibiotic-treated and stressed fish. We conclude that in carp antibiotics and stress alter the abundance and composition of the microbiota and induce Th17-dependent inflammatory reaction in the gut. Moreover, our results strongly suggest the interplay of the stress axis and the brain-gut-microbiota axis.

Brain activity during a public-speaking situation in virtual reality in patients with irritable bowel syndrome and functional dyspepsia

BACKGROUND

Psychosocial stress plays a central role in the pathophysiology of disorders of gut-brain interactions (DGBI), including functional dyspepsia (FD) and irritable bowel syndrome (IBS). Brain activity during psychosocial stress in patients with DGBI has not been adequately investigated. In this prospective study, we aimed to explore brain activity during psychosocial stress in patients with DGBI.

METHODS

Situations in an unmanned room, public space without attention, and public speaking were simulated in a virtual reality (VR) environment. Subjective stress, emotional state, and gastrointestinal (GI) symptoms were assessed using a visual analog scale, the State-Trait Anxiety Inventory, and the GI Symptom Rating Scale, respectively. Electrocardiograms were recorded to evaluate autonomic function. Activity in the prefrontal cortex (PFC) was examined using functional near-infrared spectroscopy (fNIRS).

RESULTS

Overall, 15 healthy controls, 15 patients with IBS, and 15 patients with FD were included. In the public-speaking scenario, subjective stress scores significantly decreased (indicating more stress) and sympathetic nervous activity increased equally among the three groups compared with those in an unmanned scene. Patients with IBS had higher activity in the left ventrolateral prefrontal cortex (VLPFC) and lower activity in the dorsolateral PFC (DLPFC) than those with FD and healthy controls.

CONCLUSIONS

Brain activity increased in the VLPFC and decreased in the DLPFC under stressful psychosocial situations created in the VR space in patients with IBS. Thus, the combination of VR and fNIRS is a viable option for evaluating brain activity under psychosocial stress in natural clinical settings.

Gut microbiota and their influence in brain cancer milieu

Microbial communities are not simply remnants of the past but dynamic entities that continuously evolve under the selective pressures of nature, reflecting the intricate and adaptive processes of evolution. The microbiota residing in the various regions of the human body has numerous roles in different physiological processes such as nutrition, metabolism, immune regulation, etc. In the zeal of achieving empirical insights into the ambit of the gut microbiome, the research over the years led to the revelation of reciprocal interaction between the gut microbiome and the cognitive functioning of the human body. Dysbiosis in the gut microbial composition disturbs the homeostatic cognitive functioning of the human body. This dysbiosis has been associated with various chronic diseases, including brain cancer, such as glioma, glioblastoma, etc. This review explores the mechanistic role of dysbiosis-mediated progression of brain cancers and their subtypes. Moreover, it demonstrates the regulatory role of microbial metabolites produced by the gut microbiota, such as short-chain fatty acids, amino acids, lipids, etc., in the tumour progression. Further, we also provide valuable insights into the microbiota mediating the efficiency of therapeutic regimens, thereby leveraging gut microbiota as potential biomarkers and targets for improved treatment outcomes.

The effect of corticotropin-release hormone on duodenal permeability and immune activation in healthy volunteers in a double-blind placebo-controlled study

In functional dyspepsia, increased gut permeability, low-grade inflammation, and altered sensorimotor function have been reported. Both stress and corticotropin-release hormone (CRH) have been shown to increase small bowel permeability in a mast-cell-dependent manner. Moreover, eosinophil-derived CRH has been implicated in mast cell activation. The aim of this study was to evaluate whether CRH administration alters duodenal permeability and immune activation in healthy volunteers (HVs). An intravenous bolus of 100-µg CRH or placebo was administered in HVs in a crossover, double-blind, randomized manner. Two hours later, a gastroscopy was performed to measure permeability in Ussing chambers and to count mast cells and eosinophils on duodenal biopsies. Supernatant was assessed for eosinophil-derived neurotoxin (EDN), tryptase, and chymase. In addition, CRH was administrated ex vivo to baseline biopsies pretreated with or without lodoxamide. Results are described as means ± SD. P values < 0.05 were considered significant. Twenty HVs completed the study. Mast cell or eosinophil counts were not significantly altered after CRH versus Placebo (respectively P = 0.31 and P = 0.069). Tryptase, but not chymase, significantly decreased after CRH (respectively P = 0.037 and P = 0.44) with a trend for a decrease in EDN (P = 0.053). Permeability was unaltered comparing both conditions. Ex vivo, transepithelial electrical resistance significantly decreased after CRH exposure compared with baseline (P = 0.010), which was not prevented by pretreatment with lodoxamide. In vivo CRH administration reduced tryptase levels in the supernatant of duodenal biopsies without affecting permeability, whereas ex vivo duodenal permeability increased regardless of mast cell stabilization. These results suggest the involvement of mast cells in regulating gut permeability in HVs in response to CRH, possibly influenced by in vivo compensatory mechanisms.NEW & NOTEWORTHY Our investigation breaks new ground by directly examining the effects of corticotropin-release hormone (CRH) on duodenal alterations, including permeability and immune activation, in healthy subjects. Intriguingly, our findings highlight disparities between ex vivo and in vivo pathways affecting duodenal permeability, offering novel insights into the potential pathophysiology of CRH on the duodenum.

The Duodenal Microenvironment in Functional Dyspepsia

Functional dyspepsia (FD) is a chronic gastrointestinal disorder without a readily identifiable organic cause, resulting in bothersome upper abdominal symptoms. It is a highly prevalent disorder of which the pathophysiology remains mostly elusive, despite intensive research efforts. However, recent studies have found alterations in the microenvironment of the duodenum in patients with FD. In this review we summarize the duodenal microenvironment in homeostatic conditions and the alterations found in patients with FD, highlighting the similarities and discrepancies between different studies. The most consistent findings, being an impaired duodenal barrier and duodenal immune activation, are reviewed. We discuss the potential triggers for these observed alterations, including psychological comorbidities, luminal alterations and food related triggers. In summary, this review presents the evidence of molecular and cellular changes in patients with FD, with an impaired duodenal barrier and activated mucosal eosinophils and mast cells, challenging the notion that FD is purely functional, and offering different targets for potential future treatments.

Sleep deprivation as a risk factor for anaphylaxis in children with food allergy

Severity of food allergic reactions is unpredictable, and cofactors influence the development of food-induced anaphylaxis. A lot of cofactors might increase allergic reaction severity, and little is known about sleep deprivation as a possible cofactor in food allergy, especially in children. With the description of a case of a middle child, we want to emphasise the role that sleep deprivation might play as a cofactor, especially during oral immunotherapy (OIT). She was undergoing OIT for milk and experienced anaphylaxis after ingestion of milk and sleep deprivation (sleeping time 3 hours less than the minimum optimal hours per age). No other cofactors were identified. In conclusion, sleep loss could influence the severity of adverse reactions in children with food allergies. Moreover, we propose a questionnaire to be submitted to the patient or the patient's parent prior to dose administration during OIT in order to reduce the risk of severe reactions at home.

Cooking methods affect advanced glycation end products and lipid profiles: A randomized cross-over study in healthy subjects

Thermal treatments used in ultra-processed foods (UPFs) lead to advanced glycation end products (AGEs). UPFs and serum AGEs are associated with cardiometabolic disease. We explore differential cooking methods as a mechanistic link between UPFs and detrimental health outcomes through a randomized cross-over cooking method trial in healthy subjects using identical ingredients and a deep profiling analysis. We show that low-AGE-generating cooking methods such as boiling and steaming decrease serum AGEs, improve lipid profiles, and increase serum protein 4E-BP1. In contrast, high-AGE-generating cooking methods such as grilling and baking increase fecal butyrate. In sum, this suggests that low-AGE-generating cooking methods should be considered in cardiovascular risk prevention. Since current dietary guidelines focus on ingredients, but not cooking methods, our results suggest that culinary techniques should be considered as an important factor in cardiometabolic preventive strategies and future dietary trial design. This study was registered at ClinicalTrials.gov (NCT06547190).

[Guideline on functional dyspepsia, a disorder of gut-brain-interaction (DGBI): S1 Guideline of the German Society for Neurogastroenterology and Motility (DGNM)]

Functional dyspepsia is common and classified as a disorder of gut-brain interaction (DGBI). The prevalence is estimated around 10 % of the population. Diagnosis is based on symptoms, which are based on the Rome IV criteria, in combination with diagnostic procedures that may include laboratory testing, Helicobacter pylori testing, upper gastrointestinal endoscopy, abdominal ultrasound, and other examinations, depending on the severity, duration and presence of alarming symptoms. Therapeutic procedures include psychoeducation, dietary counseling, mind-body procedures, psychotherapy and medication. The S1 guideline summarizes the current state of knowledge and allows a targeted approach based on the currently available medical evidence.

scRNA-seq of the intestine reveals the key role of mast cells in early gut dysfunction associated with acute pancreatitis

BACKGROUND

Intestinal barrier dysfunction is a prevalent and varied manifestation of acute pancreatitis (AP). Molecular mechanisms underlying the early intestinal barrier in AP remain poorly understood.

AIM

To explore the biological processes and mechanisms of intestinal injury associated with AP, and to find potential targets for early prevention or treatment of intestinal barrier injury.

METHODS

This study utilized single-cell RNA sequencing of the small intestine, alongside in vitro and in vivo experiments, to examine intestinal barrier function homeostasis during the early stages of AP and explore involved biological processes and potential mechanisms.

RESULTS

Seventeen major cell types and 33232 cells were identified across all samples, including normal, AP1 (4x caerulein injections, animals sacrificed 2 h after the last injection), and AP2 (8x caerulein injections, animals sacrificed 4 h after the last injection). An average of 980 genes per cell was found in the normal intestine, compared to 927 in the AP1 intestine and 1382 in the AP2 intestine. B cells, dendritic cells, mast cells (MCs), and monocytes in AP1 and AP2 showed reduced numbers compared to the normal intestine. Enterocytes, brush cells, enteroendocrine cells, and goblet cells maintained numbers similar to the normal intestine, while cytotoxic T cells and natural killer (NK) cells increased. Enterocytes in early AP exhibited elevated programmed cell death and intestinal barrier dysfunction but retained absorption capabilities. Cytotoxic T cells and NK cells showed enhanced pathogen-fighting abilities. Activated MCs, secreted chemokine (C-C motif) ligand 5 (CCL5), promoted neutrophil and macrophage infiltration and contributed to barrier dysfunction.

CONCLUSION

These findings enrich our understanding of biological processes and mechanisms in AP-associated intestinal injury, suggesting that CCL5 from MCs is a potential target for addressing dysfunction.

Effects of psychological stress on inflammatory bowel disease via affecting the microbiota-gut-brain axis

ABSTRACT

Inflammatory bowel disease (IBD) is an idiopathic intestinal inflammatory condition with chronic and relapsing manifestations and is characterized by a disturbance in the interplay between the intestinal microbiota, the gut, and the brain. The microbiota-gut-brain axis involves interactions among the nervous system, the neuroendocrine system, the gut microbiota, and the host immune system. Increasing published data indicate that psychological stress exacerbates the severity of IBD due to its negative effects on the microbiota-gut-brain axis, including alterations in the stress response of the hypothalamic-pituitary-adrenal (HPA) axis, the balance between the sympathetic nervous system and vagus nerves, the homeostasis of the intestinal flora and metabolites, and normal intestinal immunity and permeability. Although the current evidence is insufficient, psychotropic agents, psychotherapies, and interventions targeting the microbiota-gut-brain axis show the potential to improve symptoms and quality of life in IBD patients. Therefore, further studies that translate recent findings into therapeutic approaches that improve both physical and psychological well-being are needed.

Intestinal Permeability in Disorders of Gut-Brain Interaction: From Bench to Bedside

Intestinal barrier function lies at a critical interface of a range of peripheral and central processes that influence disorders of gut-brain interactions (DGBI). Although rigorously tested, the role of barrier dysfunction in driving clinical phenotype of DGBI remains to be fully elucidated. In vitro, in vivo, and ex vivo strategies can test various aspects of the broader permeability and barrier mechanisms in the gut. Luminal mediators of host, bacterial, and dietary origin can influence the barrier function and a disrupted barrier can also influence the luminal milieu. Critical to our understanding is how barrier dysfunction is influenced by stress and other comorbidities that associate with DGBI and the crosstalk between barrier and neural, hormonal, and immune responses. Additionally, the microbiome's significant role in the communication between the brain and gut has led to the integrative model of a microbiome gut-brain axis with reciprocal interactions between brain networks and networks composed of multiple cells in the gut, including immune cells, enterochromaffin cells, gut microbiota and the derived luminal mediators. This review highlights the techniques for assessment of barrier function, appraises evidence for barrier dysfunction in DGBI including mechanistic studies in humans, as well as provides an overview of therapeutic strategies that can be used to directly or indirectly restore barrier function in DGBI patients.

Prescription of commonly used drugs in patients with functional bowel disorders. A cross-sectional comparison with the general population

OBJECTIVES

Comorbidity with other conditions is common in functional bowel disorders. We aimed to investigate the prescription patterns of commonly used drugs in patients with irritable bowel syndrome (IBS) and functional unspecific bowel disorder, compared to the general population.

MATERIAL AND METHODS

Prescriptions of commonly used drugs in 2022 were compared between patients and the general population from the same age group and region in Sweden.

RESULTS

Of 526 patients, 317 were followed up in 2022 (219 women and 98 men) and were compared to 51,001 women and 55,571 men in the general population. The median follow-up time from the first visit to 2022 was 8 years (25th-75th percentile 6-11 years). Female patients were significantly more likely than controls to be prescribed PPIs, antibiotics, NSAIDs, paracetamol, opioids, muscle relaxants, antimigraine drugs, antidepressants and asthma medications. Male patients were significantly more likely than controls to be prescribed PPIs, opioids, antidepressants, and asthma medications. In the year prior diagnosis and through 2022, female patients showed a significant decline in the use of PPIs (38% vs.10%; p < 0.001), antibiotics (27.5% vs. 20.1%; p = 0.0426), NSAIDs (23.3% vs.14.6%; p = 0.012), opioids (20.6% vs. 7.5%; p < 0.001), and a significantly increase in the use of asthma medications (15.5% vs. 24.2%; p = 0.0088). Male patients showed a significant decline in the use of PPIs and NSAIDs.

CONCLUSION

Patients with functional bowel disorders are more likely to be prescribed medications for conditions other than IBS. Over time, there was a decline in the prescriptions of most drugs, except for antidepressants and asthma medications.

Microbial signatures and therapeutic strategies in neurodegenerative diseases

Neurodegenerative diseases (NDs), including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS), arise from complex interactions between genetic factors, environmental exposures, and aging. Additionally, gut dysbiosis has been linked to systemic inflammation and neurodegeneration. Advances in microbiome and metabolome profiling techniques have provided deeper insights into how alterations in gut microbiota and dietary patterns affect metabolic pathways and contribute to the progression of NDs. This review explores the profiles of gut microbiome and metabolome derived biomarkers and their roles in NDs. Across phyla, families, and genera, we identified 55 microbial alterations in PD, 24 in AD, 4 in ALS, and 17 in MS. Some notable results include an increase in Akkermansia in PD, AD, and MS and a decrease in short-chain fatty acids (SCFAs) in PD and AD. We examined the effects of probiotics, prebiotics, fecal microbiota transplants (FMT), sleep, exercise, and diet on the microbiota, all of which contributed to delayed onset and alleviation of symptoms. Further, artificial intelligence (AI) and machine learning (ML) algorithms applied to omics data have been crucial in identifying novel therapeutic targets, diagnosing and predicting prognosis, and enabling personalized medicine using microbiota-modulating therapies in NDs patients.

Association between adverse childhood experiences and gastro-esophageal diseases later in life: A large-population cohort and Mendelian randomization study

BACKGROUND

Adverse childhood experiences (ACEs) are widely recognized as associated with stress-associated digestive disorders, yet their comprehensive relationship with gastro-esophageal diseases as well as the potential mechanisms of depression remains underexplored.

METHODS

The prospective study included 133,638 participants aged 40-69 from UK Biobank with full information on ACEs, depression, and gastro-esophageal diseases. ACEs were retrospectively measured both as individual types (physical, emotional, and sexual abuse, and physical and emotional neglect) and cumulative scores of experienced types. Cox proportional hazards model was utilized to assess the association of ACEs with the overall and type-specific risks of diseases. Two-sample Mendelian randomization (TSMR) was conducted utilizing data from a genome-wide association study of ACEs (N = 185,414) to further examine the causal relationship. Mediation analysis was performed to quantify the role of depression.

RESULTS

During a median follow-up of 13.3 years, those who had a history of ACEs were observed with a 15 % higher overall risk of gastro-esophageal diseases (HR, 1.15; 95%CI, 1.12-1.19) and 10-25 % increased type-specific risks compared to unexposed participants. Among five individual types of ACEs, the association was more prominent for emotional abuse (1.22, 1.17-1.27) and sexual abuse (1.24, 1.18-1.30). TSMR analysis consistently reported positive associations between ACE and four subtypes of gastro-esophageal diseases. Depression was found to mediate 17.2 % (13.5 %, 24.0 %) of the aforementioned relationship.

CONCLUSIONS

Our findings highlight the importance of early screening and intervention on ACEs to reduce the long-term risk of gastro-esophageal diseases, and stress the potential of depression as a ponderable indirect intervention target.

Psychological Stress-Induced Local Immune Response to Food Antigens Increases Pain Signaling Across the Gut in Mice

BACKGROUND AND AIMS

We recently showed that a bacterial infection can break oral tolerance to food and lead to immunoglobulin E (IgE)-dependent mast cell activation and food-induced abdominal pain, which could constitute an important pathogenic mechanism in postinfectious irritable bowel syndrome (IBS). Here, we investigated whether similar immune mechanisms in response to psychological stress lead to food-evoked pain signaling, and thus potentially explain the pathophysiology in a larger group of patients with IBS.

METHODS

Mice were exposed to ovalbumin (OVA) during water avoidance stress (WAS) and re-exposed to OVA 5 weeks later. Nociception was evaluated by visceromotor responses and afferent nerve recordings to intestinal distension, and patch-clamp recordings of sensory neurons incubated with intestinal supernatants. The role of IgE and type 2 immunity was evaluated using pharmacologic and genetic approaches.

RESULTS

Re-exposure to OVA increased pain signaling in the colon and small intestine only in mice exposed to OVA during WAS, in the absence of systemic allergy. OVA-induced increases in pain responses depended on mast cells, IgE, and signal transducer and activator of transcription 6 signaling. Notably, incubation of sensory neurons with ileum and colon supernatants from WAS/OVA+OVA mice lowered their threshold of excitability. Finally, treatment with histamine receptor H1 antagonist pyrilamine blocked the increased sensory neuron excitability, and reduced ileal afferent nerve firing to distension in WAS/OVA+OVA mice.

CONCLUSIONS

Psychological stress induces a type 2 immune response to food antigens, with IgE-mediated mast cell activation and increased pain signaling in the small intestine and colon in response to food. These findings may explain the potential role of psychological stress in food-induced symptoms in IBS.

Exploring the Multifaceted Therapeutic Potential of Probiotics: A Review of Current Insights and Applications

The interplay between human health and the microbiome has gained extensive attention, with probiotics emerging as pivotal therapeutic agents due to their vast potential in treating various health issues. As significant modulators of the gut microbiota, probiotics are crucial in maintaining intestinal homeostasis and enhancing the synthesis of short-chain fatty acids. Despite extensive research over the past decades, there remains an urgent need for a comprehensive and detailed review that encapsulates probiotics' latest insights and applications. This review focusses on the multifaceted roles of probiotics in promoting health and preventing disease, highlighting the complex mechanisms through which these beneficial bacteria influence both gut flora and the human body at large. This paper also explores probiotics' neurological and gastrointestinal applications, focussing on their significant impact on the gut-brain axis and their therapeutic potential in a broad spectrum of pathological conditions. Current innovations in probiotic formulations, mainly focusing on integrating genomics and biotechnological advancements, have also been comprehensively discussed herein. This paper also critically examines the regulatory landscape that governs probiotic use, ensuring safety and efficacy in clinical and dietary settings. By presenting a comprehensive overview of recent studies and emerging trends, this review aims to illuminate probiotics' extensive therapeutic capabilities, leading to future research and clinical applications. However, besides extensive research, further advanced explorations into probiotic interactions and mechanisms will be essential for developing more targeted and effective therapeutic strategies, potentially revolutionizing health care practices for consumers.

Updated document on the management of functional dyspepsia by the Asociación Española de Neurogastroenterologia y Motilidad (ASENEM) and Sociedad Española de Medicina Familiar y Comunitaria (semFYC)

Functional dyspepsia (FD) is a gut-brain axis disorder characterized by postprandial fullness, early satiety, bloating and/or epigastric pain, which are presumed to originate in the gastroduodenal tract. While the international recommendations in the Rome IV consensus require endoscopy to rule out an organic condition before establishing a diagnosis of FD, international guidelines recommend that, in the absence of risk factors, patient management be initiated at the primary care level by establishing Helicobacter pylori infection status, with eradication when positive, followed by empiric therapy with proton pump inhibitors and/or prokinetics, and that endoscopy be reserved for patients refractory to said measures. Second-line therapy includes neuromodulating agents, among which tricyclic antidepressants and atypical antipsychotics such as levosulpiride stand out. The latter has a predominant prokinetic effect, hence it is also used as first-line therapy for patients where early satiety and postprandial fullness predominate. Other therapy alternatives include phytotherapy using STW5 or peppermint/caraway oil, which have shown their superiority over placebo in controlled studies. Concurrently, dietary and lifestyle counseling, as well as psychological interventions such as cognitive-behavioral therapy, when available, may represent a therapeutic alternative worth considering for some patients.

Beyond the "Master" Role in Allergy: Insights into Intestinal Mast Cell Plasticity and Gastrointestinal Diseases

Mast cells (MCs) are essential components of the immune system that enter the circulation as immature bone marrow progenitors and differentiate in peripheral organs under the influence of microenvironment factors. As tissue-resident secretory immune cells, MCs rapidly detect the presence of bacteria and parasites because they harbor many surface receptors, which enable their activation via a multitude of stimuli. MC activation has been traditionally linked to IgE-mediated allergic reactions, but MCs play a pivotal role in different physiological and pathological processes. In gut, MCs are essential for the maintenance of gastrointestinal (GI) barrier function, and their interactions with neurons, immune cells, and epithelial cells have been related to various GI disorders. This review recapitulates intestinal MC roles in diseases with a main focus on inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Emerging therapies targeting MCs and their mediators in clinical practices will also be discussed.

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.

Key Taxa of the Gut Microbiome Associated with the Relationship Between Environmental Sensitivity and Inflammation-Related Biomarkers

Individual differences in environmental sensitivity are linked to stress-related psychiatric symptoms. In previous research, we found that high environmental sensitivity can be a risk factor for increased inflammation and gut permeability, particularly when gut microbiome diversity is low. However, the specific gut bacterial taxa involved in this interaction remain unclear. As a preliminary study, this research aimed to identify the key gut microbiome taxa associated with this relationship. Environmental sensitivity, gut microbiome composition, gut permeability (lipopolysaccharide-binding protein, LBP), and inflammation (C-reactive protein, CRP) biomarkers were evaluated in 88 participants. The interaction between environmental sensitivity and the relative abundance of the family Marinifilaceae (genus Butyricimonas) was a predictor of CRP levels. Similarly, the interaction between environmental sensitivity and relative abundance of the family Barnesiellaceae (genus Coprobacter), the family Akkermansiaceae (genus Akkermansia), the genus Family XIII AD3011 group, the genus GCA-900066225, or the genus Ruminiclostridium 1 predicted LBP levels. Individuals with high environmental sensitivity exhibited elevated CRP or LBP levels when the relative abundance of these taxa was low. Conversely, highly sensitive individuals had lower CRP or LBP levels when the relative abundance of these taxa was high. This study suggests that specific taxa serve as one of the protective factors against inflammation and gut permeability in individuals with high environmental sensitivity. Further in-depth studies are needed to confirm these associations and understand the underlying mechanisms.

Acute stress triggers sex-dependent rapid alterations in the human small intestine microbiota composition

Background/aims

Digestive disorders of gut-brain interaction (DGBI) are very common, predominant in females, and usually associated with intestinal barrier dysfunction, dysbiosis, and stress. We previously found that females have increased susceptibility to intestinal barrier dysfunction in response to acute stress. However, whether this is associated with changes in the small bowel microbiota remains unknown. We have evaluated changes in the small intestinal microbiota in response to acute stress to better understand stress-induced intestinal barrier dysfunction.

Methods

Jejunal biopsies were obtained at baseline and 90 min after cold pain or sham stress. Autonomic (blood pressure and heart rate), hormonal (plasma cortisol and adrenocorticotropic hormone) and psychological (Subjective Stress Rating Scale) responses to cold pain and sham stress were monitored. Microbial DNA from the biopsies was analyzed using a 16S metabarcoding approach before and after cold pain stress and sham stress. Differences in diversity and relative abundance of microbial taxa were examined.

Results

Cold pain stress was associated with a significant decrease in alpha diversity (P = 0.015), which was more pronounced in females, along with significant sex differences in the abundance of specific taxa and the overall microbiota composition. Microbiota alterations significantly correlated with changes in psychological responses, hormones, and gene expression in the intestinal mucosal. Cold pain stress was also associated with activation of autonomic, hormonal and psychological response, with no differences between sexes.

Conclusions

Acute stress elicits rapid alterations in bacterial composition in the jejunum of healthy subjects and these changes are more pronounced in females. Our results may contribute to the understanding of female predominance in DGBI.

Elevated IL-22 as a result of stress-induced gut leakage suppresses septal neuron activation to ameliorate anxiety-like behavior

Psychological stress and its sequelae pose a major challenge to public health. Immune activation is conventionally thought to aggravate stress-related mental diseases such as anxiety disorders and depression. Here, we sought to identify potentially beneficial consequences of immune activation in response to stress. We showed that stress led to increased interleukin (IL)-22 production in the intestine as a result of stress-induced gut leakage. IL-22 was both necessary and sufficient to attenuate stress-induced anxiety behaviors in mice. More specifically, IL-22 gained access to the septal area of the brain and directly suppressed neuron activation. Furthermore, human patients with clinical depression displayed reduced IL-22 levels, and exogenous IL-22 treatment ameliorated depressive-like behavior elicited by chronic stress in mice. Our study thus identifies a gut-brain axis in response to stress, whereby IL-22 reduces neuronal activation and concomitant anxiety behavior, suggesting that early immune activation can provide protection against psychological stress.

Metagenomic symphony of the intestinal ecosystem: How the composition affects the mind

Mental health disorders and neurodegenerative diseases place a heavy burden on patients and societies, and, although great strides have been made to understand the pathophysiology of these conditions, advancement in drug development is lagging. The importance of gastrointestinal health in maintaining overall health and preventing disease is not a new concept. Hundreds of years ago, healers from various cultures and civilizations recognized the crucial role of the gut in sustaining health. More than a century ago, scientists began exploring the restorative effects of probiotics, marking the early recognition of the importance of gut microbes. The omics era brought more enlightenment and enabled researchers to identify the complexity of the microbial ecosystems we harbour, encompassing bacteria, eukaryotes (including fungi), archaea, viruses, and other microorganisms. The extensive genetic capacity of the microbiota is dynamic and influenced by the environment. The microbiota therefore serves as a significant entity within us, with evolutionarily preserved functions in host metabolism, immunity, development, and behavior. The significant role of the bacterial gut microbiome in mental health and neurodegenerative disorders has been realized and described within the framework of the microbiota-gut-brain axis. However, the bacterial members do not function unaccompanied, but rather in concert, and there is a substantial knowledge gap regarding the involvement of non-bacterial microbiome members in these disorders. In this review, we will explore the current literature that implicates a role for the entire metagenomic ensemble, and how their complex interkingdom relationships could influence CNS functioning in mental health disorders and neurodegenerative diseases.

Stress-induced VIPergic activation mediates microbiota/Th17cell-dependent depressive-like behaviors

Chronic stress often has deleterious effects leading to the development of psychiatric diseases. The gut-brain axis represents a novel avenue for stress research. The negative effects of stress on the gut physiology have been well-described, whereas the pathways whereby stress controls microbial composition to modulate behaviors remains mainly unknown. We discovered that vasoactive intestinal peptide (VIP) activation promoted stress-induced microbial changes leading to increased infiltration of T helper (Th) 17 cells and microglial activation in the hippocampus and depressive-like behaviors, uncovering a close crosstalk between intestinal VIPergic release and the gut microbiota during stress and providing a new interaction between the nervous system and the gut microbiome after stress. Neutralization of the signature cytokine of Th17 cells, interleukin (IL)-17A, was sufficient to block depressive-like behaviors, reduce neuronal VIPergic activation and microglia activation induced by VIPergic activation after stress, opening new potential therapeutic targets for depression.

Metabolomic Signatures Highlight Fiber-Degrading Bacteroides Species in Mediterranean Diet Response Among Ulcerative Colitis

Background and Aims

The Mediterranean diet pattern (MDP) is associated with health-associated gut microbes and metabolites. However, the impact of the MDP on the fecal metabolome in ulcerative colitis (UC) remains unclear. We characterized the fecal metabolome of patients with UC with high adherence to the MDP compared to the Canadian habitual diet (CHD). Furthermore, we explored potential differences in the fecal metabolome between dietary responders and nonresponders to the MDP.

Methods

Utilizing untargeted metabolomics on a subset of fecal samples obtained from a randomized controlled trial, adult patients with quiescent UC underwent a 12-week intervention following either the MDP (n = 8) or CHD (n = 8). Liquid chromatography-tandem mass spectrometry was employed to profile endogenous fecal metabolites, while 16S amplicon sequencing was utilized to profile the fecal microbiota.

Results

A total of 701 human metabolites were detected, with 35 exhibiting significant differential expression between the MDP and CHD groups. Noteworthy, folate biosynthesis, sphingolipid biosynthesis, and steroid biosynthesis were identified as major pathways affected. Moreover, microbial analysis showed that individuals with increased levels of the class Bacteroidia (Bacteroides vulgatus [B. vulgatus], B. uniformis, and B. acidifaciens) in their stool at baseline were more likely to respond to the MDP.

Conclusion

High adherence to an MDP is associated with beneficial metabolite changes associated with reducing inflammation in UC. In addition, fiber-degrading microbes abundant before dietary intervention played a role in the responsiveness to the MDP. This work lays the groundwork for developing a metabolic signature associated with the MDP to develop personalized nutrition strategies for UC prevention and treatment. ClinicalTrials.gov Number: NCT03053713.

Gut Microbiota, Bacterial Translocation, and Stroke: Current Knowledge and Future Directions

Stroke is one of the most devastating pathologies in terms of mortality, cause of dementia, major adult disability, and socioeconomic burden worldwide. Despite its severity, treatment options remain limited, with no pharmacological therapies available for hemorrhagic stroke (HS) and only fibrinolytic therapy or mechanical thrombectomy for ischemic stroke (IS). In the pathophysiology of stroke, after the acute phase, many patients develop systemic immunosuppression, which, combined with neurological dysfunction and hospital management, leads to the onset of stroke-associated infections (SAIs). These infections worsen prognosis and increase mortality. Recent evidence, particularly from experimental studies, has highlighted alterations in the microbiota-gut-brain axis (MGBA) following stroke, which ultimately disrupts the gut flora and increases intestinal permeability. These changes can result in bacterial translocation (BT) from the gut to sterile organs, further contributing to the development of SAIs. Given the novelty and significance of these processes, especially the role of BT in the development of SAIs, this review summarizes the latest advances in understanding these phenomena and discusses potential therapeutic strategies to mitigate them, ultimately reducing post-stroke complications and improving treatment outcomes.

Personalisation of therapy in irritable bowel syndrome: a hypothesis

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction characterised by symptoms of abdominal pain, occurring at least 1 day per week, and a change in stool frequency or form. Individuals with IBS are usually subtyped according to their predominant bowel habit, which is used to direct symptom-based treatment. However, this approach is probably an oversimplification of a complex and multidimensional condition, and other factors, such as psychological health, are known to influence symptom severity and prognosis. We have previously used latent class analysis, a method of mathematical modelling, to show that people with IBS can be classified into seven unique clusters based on a combination of gastrointestinal symptoms, abdominal pain, extraintestinal symptoms, and psychological comorbidity. The clusters can be used to predict the prognosis of IBS (eg, symptom severity), health-care use (eg, consultation behaviour, prescribing, and costs), and impact (eg, quality of life, work and productivity, activities of daily living, and income). These clusters could also be used to increase the personalisation of IBS treatment that better recognises the heterogenous nature of the condition. We present new data providing additional validation of our seven-cluster model and conduct a comprehensive evidence-based review of IBS management. Based on this evidence, we propose a framework of first-line and second-line treatments according to IBS cluster. Finally, we discuss what further research is needed to implement this approach in clinical practice, including the need for randomised trials comparing cluster-based treatment with conventional treatment according to stool subtype.

Lipopolysaccharide-mediated effects of the microbiota on sleep and body temperature

Recent research suggests that microbial molecules translocated from the intestinal lumen into the host's internal environment may play a role in various physiological functions, including sleep. Previously, we identified that butyrate, a short-chain fatty acid produced by intestinal bacteria, and lipoteichoic acid, a cell wall component of gram-positive bacteria, induce sleep when their naturally occurring translocation is mimicked by direct delivery into the portal vein. Building upon these findings, we aimed to explore the sleep signaling potential of intraportally administered lipopolysaccharide (LPS), a primary component of gram-negative bacterial cell walls, in rats. Low dose of LPS (1 μg/kg) increased sleep duration and prolonged fever, without affecting systemic LPS levels. Interestingly, administering LPS systemically outside the portal region at a dose 20 times higher did not affect sleep, indicating a localized sensitivity within the hepatoportal region for the sleep and febrile effects of LPS. Furthermore, both the sleep- and fever-inducing effects of LPS were inhibited by indomethacin, a prostaglandin synthesis inhibitor, and replicated by intraportal administration of prostaglandin E2 or arachidonic acid, suggesting the involvement of the prostaglandin system in mediating these actions.

The effects of a 6-week intervention with Limosilactobacillus reuteri ATCC PTA 6475 alone and in combination with L. reuteri DSM 17938 on gut barrier function, immune markers, and symptoms in patients with IBS-D-An exploratory RCT

BACKGROUND

An increased intestinal permeability is a common feature in patients with diarrhoea-predominant irritable bowel syndrome (IBS-D). Probiotics have shown to improve IBS symptoms and might also affect intestinal barrier function.

AIM

The aim of this study was to investigate the effects of a 6-week intervention with Limosilactobacillus reuteri ATCC PTA 6475 alone (single strain) or in combination with Limosilactobacillus reuteri DSM 17938 (dual strain) on gut barrier function, immune markers, and symptoms in IBS-D patients (ClinicalTrials.gov registration number: NCT03986476).

METHODS

65 IBS-D patients were randomised into three groups (placebo, single strain, dual strain). Small and large intestinal permeability were assessed using a multi-sugar urinary recovery test. Blood, saliva, faecal samples, and several symptom scales were collected before, and after three and six weeks of intervention.

RESULTS

Small and large intestinal permeability as well as other markers of gut barrier function were not significantly affected by the probiotic interventions. Serum IL-6 levels showed a tendency to be reduced in the single strain group (descriptive p = 0.052). In addition, high-sensitivity C-reactive protein was significantly reduced in the dual strain group (p = 0.041). The participants in both treatment groups reported less gastrointestinal symptoms after three weeks, but this reached significance only in the dual strain group (total score: p = 0.032, pain subscore: p = 0.028). After six weeks, none of the assessed symptoms were significantly different from the placebo.

CONCLUSION

The probiotic compounds investigated in this study did not seem to affect IBS-D patients' gut barrier function, but showed potential anti-inflammatory and symptom-improving properties, which need to be confirmed in larger study cohorts.

The Influence of Maternal Lifestyle Factors on Human Breast Milk Microbial Composition: A Narrative Review

Human breast milk (HBM) is considered the gold standard for infant nutrition due to its optimal nutrient profile and complex composition of cellular and non-cellular components. Breastfeeding positively influences the newborn's gut microbiota and health, reducing the risk of conditions like gastrointestinal infections and chronic diseases (e.g., allergies, asthma, diabetes, and obesity). Research has revealed that HBM contains beneficial microbes that aid gut microbiota maturation through mechanisms like antimicrobial production and pathogen exclusion. The HBM microbiota composition can be affected by several factors, including gestational age, delivery mode, medical treatments, lactation stage, as well as maternal lifestyle habits (e.g., diet, physical activity, sleep quality, smoking, alcohol consumption, stress level). Particularly, lifestyle factors can play a significant role in shaping the HBM microbiota by directly modulating the microbial composition or influencing the maternal gut microbiota and influencing the HBM microbes through the enteromammary pathway. This narrative review of current findings summarized how maternal lifestyle influences HBM microbiota. While the influence of maternal diet on HBM microbiota is well-documented, indicating that dietary patterns, especially those rich in plant-based proteins and complex carbohydrates, can positively influence HBM microbiota, the impact of other lifestyle factors is poorly investigated. Maintaining a healthy lifestyle during pregnancy and breastfeeding is crucial for the health of both mother and baby. Understanding how maternal lifestyle factors influence microbial colonization of HBM, along with their interactions and impact, is key to developing new strategies that support the beneficial maturation of the infant's gut microbiota.

Microbiota-gut-brain axis in perioperative neurocognitive and depressive disorders: Pathogenesis to treatment

An increasing number of people undergo anesthesia and surgery. Perioperative neurocognitive and depressive disorders are common central nervous system complications with similar pathogeneses. These conditions pose a deleterious threat to human health and a significant societal burden. In recent years, numerous studies have focused on the role of the gut microbiota and its metabolites in the central nervous system via the gut-brain axis. Its involvement in perioperative neurocognitive and depressive disorders has attracted considerable attention. This review aimed to elucidate the role of the gut microbiota and its metabolites in the pathogenesis of perioperative neurocognitive and depressive disorders, as well as the value of targeted interventions and treatments.

Letter: Dietary emulsifiers and intestinal health-The beginning of an evolving story: Authors' reply

This article is linked to Fitzpatrick et al papers. To view these articles, visit https://doi.org/10.1111/apt.18172 and https://doi.org/10.1111/apt.18226

The effect of dietary emulsifiers and thickeners on intestinal barrier function and its response to acute stress in healthy adult humans: A randomised controlled feeding study

BACKGROUND

Although dietary emulsifiers are implicated in the pathogenesis of Crohn's disease, their effect has not been studied in humans.

AIM

To determine the effects of high- and low-emulsifier diets (HED, LED) on intestinal barrier function in healthy subjects in unstressed and acutely stressed states.

METHODS

We conducted a single-blinded, cross-over, controlled feeding trial in 22 healthy adults. After recording 7 days of their habitual diet, we randomised participants to HED or LED with ≥3-week washout between diets. On dietary completion, acute stress was induced via intravenous corticotrophin-releasing hormone. We assessed dietary adherence, effects on 2-h urinary lactulose: rhamnose ratio (LRR), serum concentrations of lipopolysaccharide-binding protein, soluble-CD14 and markers of epithelial injury and inflammation.

RESULTS

Dietary adherence was excellent. In an unstressed state, median (interquartile range) LRR during HED was 0.030 (0.018-0.042); on LED, this was 0.042 (0.029-0.078; p = 0.04). LPB concentrations were lower on HED than LED (p = 0.026), but no differences were observed for epithelial injury or inflammation. Under acute stress, LRR increased by 89% (-1% to 486%) on HED (p = 0.004), differing (p = 0.001) from 39% (1%-90%) decrease on LED (p = 0.009). Soluble-CD14 also increased (p < 0.001). The LED had a prolonged carry-over effect on suppressing HED-induced changes during stress. Similar changes in LRR and soluble-CD14 were observed when HED was used as the first diet (both p < 0.01).

CONCLUSION

High intake of emulsifiers improved barrier function in the unstressed state, but increased intestinal permeability to stress, without evidence of inflammation. A LED was protective of the stress effect.

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.

Breaking the Barrier: The Role of Gut Epithelial Permeability in the Pathogenesis of Hypertension

PURPOSE OF THE REVIEW

To review what intestinal permeability is and how it is measured, and to summarise the current evidence linking altered intestinal permeability with the development of hypertension.

RECENT FINDINGS

Increased gastrointestinal permeability, directly measured in vivo, has been demonstrated in experimental and genetic animal models of hypertension. This is consistent with the passage of microbial substances to the systemic circulation and the activation of inflammatory pathways. Evidence for increased gut permeability in human hypertension has been reliant of a handful of blood biomarkers, with no studies directly measuring gut permeability in hypertensive cohorts. There is emerging literature that some of these putative biomarkers may not accurately reflect permeability of the gastrointestinal tract. Data from animal models of hypertension support they have increased gut permeability; however, there is a dearth of conclusive evidence in humans. Future studies are needed that directly measure intestinal permeability in people with hypertension.

Long-Term Vonoprazan and Acotiamide-Refractory Patients With Functional Dyspepsia Partly Exhibit Pancreatic Enzyme Abnormalities

BACKGROUND

Although a new potassium-competitive acid blocker (P-CAB) vonoprazan has been developed in Japan, no data are available regarding long-term vonoprazan or vonoprazan and acotiamide combination treatment in patients with functional dyspepsia (FD).

METHODOLOGY

A total of 73 consecutive patients with FD diagnosed according to the Rome III classification were enrolled. Forty-two patients with FD were treated with vonoprazan monotherapy and thirty-one patients with FD were treated with vonoprazan and acotiamide combination therapy for 24 weeks. The levels of five pancreatic enzymes were measured, and the overall treatment efficacy (OTE) was defined as the ratio of FD patients with improved or unchanged in all items of GSRS and FD symptom scores after the treatment.

RESULTS

Treatment with vonoprazan monotherapy and vonoprazan and acotiamide combination therapy significantly improved FD symptoms. There were no significant differences in OTE between patients treated with vonoprazan monotherapy (42.9%) and those treated with vonoprazan and acotiamide combination therapy (52%). There were no significant differences in duodenal eosinophilic infiltration between the improved and unimproved groups treated with vonoprazan alone and vonoprazan and acotiamide combination therapy, respectively. In contrast, there was a significant difference (P = 0.004) in the ratio of pancreatic enzyme abnormalities between the improved and unimproved patients treated with vonoprazan monotherapy and those treated with vonoprazan and acotiamide combination therapy.

CONCLUSIONS

Long-term vonoprazan alone or vonoprazan and acotiamide combination therapy significantly improved each FD symptom. The OTE in patients treated with vonoprazan alone or vonoprazan and acotiamide combination therapy was only 50%. Long-term vonoprazan and acotiamide combination therapy may differentiate patients with pancreatic enzyme abnormalities from those with FD.

The Intersection of Ultra-Processed Foods, Neuropsychiatric Disorders, and Neurolaw: Implications for Criminal Justice

Over the last decade there has been increasing interest in the links between the consumption of ultra-processed foods and various neuropsychiatric disorders, aggression, and antisocial behavior. Neurolaw is an interdisciplinary field that seeks to translate the rapid and voluminous advances in brain science into legal decisions and policy. An enhanced understanding of biophysiological mechanisms by which ultra-processed foods influence brain and behavior allows for a historical reexamination of one of forensic neuropsychiatry's most famous cases-The People v. White and its associated 'Twinkie Defense'. Here in this Viewpoint article, we pair original court transcripts with emergent research in neurolaw, including nutritional neuroscience, microbiome sciences (legalome), pre-clinical mechanistic research, and clinical intervention trials. Advances in neuroscience, and related fields such as the microbiome, are challenging basic assumptions in the criminal justice system, including notions of universal free will. Recent dismissals of criminal charges related to auto-brewery syndrome demonstrate that courts are open to advances at the intersection of neuromicrobiology and nutritional neuroscience, including those that relate to criminal intent and diminished capacity. As such, it is our contention that experts in the neurosciences will play an increasing role in shaping research that underpins 21st-century courtroom discourse, policy, and decision-making.

Nemo mRNA vaccination improves airway barrier function in mice with airway allergy

Epithelial barrier dysfunction plays an important role in the pathogenesis of Th2 bias. The mechanism requires further clarification. NEMO is associated with regulating apoptotic activities in the cell. The purpose of this study is to investigate the role of insufficient Nemo signals in developing Th2 bias in the respiratory tract. Nemof/fEpcam-Cre mice (A mouse strain carrying NEMO-deficient epithelial cells. NemoKO mice, in short) was generated. An airway Th2 bias mouse model was established with the ovalbumin/alum protocol. The NemoKO mice exhibited spontaneous airway Th2 bias. Respiratory tract epithelial barrier integrity was compromised in NemoKO mice. Apoptosis was found in approximately 10% of the epithelial cells of the respiratory tract in NemoKO mice. The reconstruction of the Nemo expression restored homeostasis within the epithelial barrier of the airways. Restoration of Nemo gene expression in epithelial cells by Nemo mRNA vaccination alleviated Th2 bias in mice with airway allergy. To sum up, NEMO plays an important role in maintaining the integrity of the epithelial barrier in the respiratory tract. Administration of NEMO mRNA vaccines can restore epithelial barrier functions and alleviate Th2 bias in the airways.

Validation of an in vivo dual permeability marker technique to characterize regional gastrointestinal tract permeability in mid lactation Holstein cows during short-term feed restriction

This study evaluated the impact of short-term feed restriction in lactating dairy cows on regional permeability of the gastrointestinal tract (GIT), and the recovery of DMI, ruminal pH, and milk yield. In addition, sampling methods for a novel dual marker technique to characterize total GIT and post ruminal permeability were validated. Six ruminally cannulated lactating Holstein cows were blocked by parity (3 primiparous, 3 multiparous; 189 DIM ± 25.2) and enrolled in a crossover design. Experimental periods included a 5-d baseline phase (BASE), 5-d challenge phase (CHAL), and 2 weeks of recovery (REC1 and REC2). During CHAL cows received either 100% ad libitum feed intake (AL) or 40% of ad libitum feed intake (FR). To assess, total-tract and post-ruminal permeability, equimolar doses of Cr-EDTA and Co-EDTA were infused on d 3 of CHAL into the rumen and abomasum (0.369 mmol/kg BW). Following infusions, total urine and feces were collected every 8 h over 96 h, and blood samples were collected at h 0, 1, 2, 3, 4, 6, 8, 12, 16, 20, 24, 32, 40, 48, and 64. The plasma area under the curve (AUC) for Cr and Co were calculated. By design, DMI for FR was reduced by 60% during CHAL and remained 19% lower than AL during REC1 but was not different from AL in REC2. Mean ruminal pH for FR was greatest during CHAL and the least during REC1, with no differences detected between AL and FR in REC2. The duration that pH was < 5.8 was the least for FR during CHAL and greatest during REC1 which were different from AL and were no longer different between treatments in REC2. Milk yield was the least for FR during CHAL and REC1 and no longer different from AL in REC2. Feed restriction reduced milk fat, protein, and lactose yields by 26, 31% and 31%, respectively. Plasma Cr AUC was 34% greater and Co AUC tended to be 35% greater for FR than AL on d 3 of CHAL. Urinary Cr recovery after 48-h was not affected by treatment; however, urinary Co recovery was 36% greater for FR than AL. Positive correlations between plasma AUC and urinary recovery for Cr and Co were detected. It was determined that blood samples collected at h 2, 8, 20, 40, and 48 could predict the total plasma Cr and Co AUC within 1.9% and 6.2%, respectively. In summary, short-term FR in lactating dairy cows increases permeability of the total GIT and may increase permeability of the post-ruminal regions with more than 60% of the permeability occurring post-ruminally. After FR, cows experienced low ruminal pH and a sustained reduction in milk yield. When utilizing Cr- and Co-EDTA to evaluate regional GIT permeability, plasma AUC can be used as an alternate to urinary Cr and Co excretion. In addition, blood samples collected at h 2, 8, 20, 40, and 48 result in adequate prediction accuracy, at least when comparing GIT permeability for lactating dairy cows exposed to AL and FR.

Neuromicrobiology Comes of Age: The Multifaceted Interactions between the Microbiome and the Nervous System

The past decade has seen an explosion in our knowledge about the interactions between gut microbiota, the central nervous system, and the immune system. The gut-brain axis has recently gained much attention due to its role in regulating host physiology. This review explores recent findings concerning potential pathways linking the gut-brain axis to the initiation, pathophysiology, and development of neurological disorders. Our objective of this work is to uncover causative factors and pinpoint particular pathways and therapeutic targets that may facilitate the translation of experimental animal research into practical applications for human patients. We highlight three distinct yet interrelated mechanisms: (1) disruptions of both the intestinal and blood-brain barriers, (2) persistent neuroinflammation, and (3) the role of the vagus nerve.

Gastrointestinal adverse reaction to food (GARF) and endoscopic confocal laser endomicroscopy (eCLE)

BACKGROUND AND STUDY AIMS

Gastrointestinal adverse reaction to food (GARF) is reported frequently in the general population and even more in patients with disorders of the gut brain axis. However, there is a significant difference between self-reported and objective proven GARF. The aim of the study was to characterize a mucosal correlate of GARF by endoscopic confocal laser endomicroscopy (eCLE) with duodenal food challenge (DFC).

PATIENTS AND METHODS

In an observational and proof of concept study we evaluated 71 patients with disorders of the gut brain axis without (group I, n=19) and with (group II, n=52) GARF by eCLE and DFC. Spontaneous and food induced transfer of fluorescein into duodenal lumen was detected 10 minutes following intravenously application of fluorescein and 10 minutes after DFC.

RESULTS

According to Rom IV, the patients (group I/II) could be classified as irritable bowel syndrome (IBS) 32%/31%, functional abdominal pain without changes in bowel movement 47 %/48 %, functional abdominal bloating/distension 0 %/10 %, functional diarrhea 5 %/ 2 %, and unspecified functional bowel disorder 16 %/10 %, respectively. 21 %/27 % of the patients responded with a fluorescein leakage into the duodenal lumen before and 74 %/69 % following to DFC. Frequency rank order of food components that induced a response were soy (55.5 %/60 %), wheat (60 %/45.5 %), egg (35.7 %/8.3), milk (30 %/18.2 %) and yeast (10 %/6.6 %), respectively. Histology of duodenal biopsies, number, form and distribution of intraepithelial lymphocytes and mucosal mast cells as well as mast cell function were normal. Overall, 14 %/79 % reported main symptom benefit following a food exclusion therapy according to eCLE and DFC that was significant different between the groups.

CONCLUSION

The results of our study indicate that eCLE with DFC is a technique to clinically evaluate patients with disorders of the gut brain axis and GARF resulting in a high proportion of patients reporting symptom benefit upon food exclusion dietary advice focussed on the results of eCLE.

Docosahexaenoic acid (DHA) promotes recovery from postoperative ileus and the repair of the injured intestinal barrier through mast cell-nerve crosstalk

The objective of this study was to investigate the neuroimmune mechanisms implicated in the enhancement of gastrointestinal function through the administration of oral DHA. Mast cell-deficient mice (KitW-sh) and C57BL/6 mice were used to establish postoperative ileus (POI) models. To further validate our findings, we conducted noncontact coculture experiments involving dorsal root ganglion (DRG) cells, bone marrow-derived mast cells (BMMCs) and T84 cells. Furthermore, the results obtained from investigations conducted on animals and cells were subsequently validated through clinical trials. The administration of oral DHA had ameliorative effects on intestinal barrier injury and postoperative ileus. In a mechanistic manner, the anti-inflammatory effect of DHA was achieved through the activation of transient receptor potential ankyrin 1 (TRPA1) on DRG cells, resulting in the stabilization of mast cells and increasing interleukin 10 (IL-10) secretion in mast cells. Furthermore, the activation of the pro-repair WNT1-inducible signaling protein 1 (WISP-1) signaling pathways by mast cell-derived IL-10 resulted in an enhancement of the intestinal barrier integrity. The current study demonstrated that the neuroimmune interaction between mast cells and nerves played a crucial role in the process of oral DHA improving the intestinal barrier integrity of POI, which further triggered the activation of CREB/WISP-1 signaling in intestinal mucosal cells.

Investigating the molecular mechanisms underlying the co-occurrence of Parkinson's disease and inflammatory bowel disease through the integration of multiple datasets

Parkinson's disease (PD) and inflammatory bowel disease (IBD) are chronic diseases affecting the central nervous system and gastrointestinal tract, respectively. Recent research suggests a bidirectional relationship between neurodegeneration in PD and intestinal inflammation in IBD. PD patients may experience gastrointestinal dysfunction over a decade before motor symptom onset, and IBD may increase the risk of developing PD. Despite the "gut-brain axis" concept, the underlying pathophysiological mechanisms of this potential association remain unclear. This study aimed to investigate the biological mechanisms of differentially expressed genes in PD and IBD using bioinformatics tools, providing novel insights into the co-diagnosis and treatment of these diseases. We constructed a gene marker for disease diagnosis and identified five important genes (BTK, NCF2, CRH, FCGR3A and SERPINA3). Through nomogram and decision tree analyses, we found that both the IBD and PD required only the expression levels of BTK and NCF2 for accurate discrimination. Additionally, small molecule drugs RO-90-7501 and MST-312 may be useful for the treatment of both IBD and PD. These findings offer new perspectives on the co-diagnosis and treatment of PD and IBD, and suggest that targeting BTK may be a promising therapeutic strategy for both diseases.

Acupuncture influences multiple diseases by regulating gut microbiota

Acupuncture, an important green and side effect-free therapy in traditional Chinese medicine, is widely use both domestically and internationally. Acupuncture can interact with the gut microbiota and influence various diseases, including metabolic diseases, gastrointestinal diseases, mental disorders, nervous system diseases, and other diseases. This review presents a thorough analysis of these interactions and their impacts and examines the alterations in the gut microbiota and the potential clinical outcomes following acupuncture intervention to establish a basis for the future utilization of acupuncture in clinical treatments.

ReFerm®: a postbiotic fermented oat gruel composition is reducing mast cell degranulation in the colon of patients with irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder that affects ~4% of the global population. ReFerm® is a postbiotic product derived from oat gruel fermented with Lactobacillus plantarum 299v, and it has been shown to have beneficial effects on intestinal permeability in patients with IBS. In this study, we investigated the effects of ReFerm® on regulators of intestinal permeability, namely mast cells and enteric glial cells.

MATERIALS AND METHODS

A total of 30 patients with moderate to severe IBS were treated with an enema containing ReFerm® or a placebo twice daily. The patients underwent sigmoidoscopy with biopsies obtained from the distal colon at baseline and after 14 days of treatment. These biopsies were processed in two ways: some were fixed, embedded in paraffin, sectioned, and stained for mast cells and enteric glial cells; others were cryopreserved, lysed, and subjected to Western blotting to analyze the same markers.

RESULTS

Treatment with ReFerm®, but not the placebo, significantly reduced mast cell tryptase protein levels in the biopsy lysates. Although the number of mast cells remained unchanged in colonic biopsies, ReFerm® treatment significantly reduced mast cell degranulation, a result not observed in the placebo group. Neither ReFerm® or placebo treatment had an impact on total protein levels or the number of enteric glial cells in the biopsies.

CONCLUSION

ReFerm® treatment significantly reduced both total mast cell tryptase levels and the degranulation of mast cells in colonic biopsies from patients with IBS, suggesting a decrease in mast cell activity as a potential mechanism underlying the beneficial effects of ReFerm®. However, further research is required to assess the molecular mechanisms through which ReFerm® operates in the colons of patients with IBS.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov, identifier: NCT05475314.

The Leuven Prolonged Acute Stress Test (L-PAST): A novel paradigm to induce a subjective and glucocorticoid stress response for at least ninety minutes

Laboratory stress tests typically administer stress acutely, ranging from 3 to 15 minutes. However, everyday stressors usually last longer than ten minutes (e.g., examination stressors, work stressors, and social stressors. Moreover, in some studies, it may be relevant to induce stress for a longer period to affect certain psychological or physiological parameters. To this end, we developed a novel stress test that intends to induce psychosocial stress for 90 minutes. The Leuven Prolonged Acute Stress Test (L-PAST) combines physical (hand immersion in cold water), cognitive (mental arithmetic), and psychosocial (social evaluation and feelings of failure) stress elements of two well-known laboratory stress tests, the Maastricht Acute Stress Test (MAST) and the Montreal Imaging Stress Test (MIST). Fifty healthy women were subjected to both the L-PAST and a sham (control) test in a randomized and counterbalanced manner. The stress response was determined by salivary cortisol measurements and assessment of subjective stress ratings at regular time points during the time preceding the stress period (5 min), the stress period (90 min), and the recovery period (35 min). Cognitive reactivity to failure and subjective pain levels were also assessed at various time points. The childhood trauma questionnaire (CTQ) and the perceived stress scale (PSS) were administered prior to the testing phase. As expected, linear mixed models revealed that the stress response was significantly higher during the L-PAST as indicated by a significant time point by condition interaction effect for both the cortisol response (F(10,450)=12.21, p < 0.0001, ηp2=0.11) and the subjective stress response (F(13,637)=13.98, p < 0.0001, ηp2 = 0.12). Moreover, there was a significant time point by condition interaction effect for cognitive reactivity to failure (F(13,637) = 7.97, p < 0.0001, ηp2 = 0.07) and subjective pain (F(13,637) = 38.52, p < 0.0001, ηp2 = 0.27), indicating that the levels were higher during the L-PAST at most stress induction time points. Lastly, higher CTQ scores were associated with higher subjective pain levels during the L-PAST (F(1,44)=6.05, p = 0.02). Collectively, our results confirm the efficacy of the L-PAST in inducing a prolonged subjective as well as cortisol stress response.

HucMSC-Ex alleviates DSS-induced colitis in mice by decreasing mast cell activation via the IL-33/ST2 axis

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory disease that poses challenges in terms of treatment. The precise mechanism underlying the role of human umbilical cord mesenchymal stem cell-derived exosome (HucMSC-Ex) in the inflammatory repair process of IBD remains elusive. Mucosal mast cells accumulate within the intestinal tract and exert regulatory functions in IBD, thus presenting a novel target for addressing this intestinal disease.

METHODS

A mouse model of Dextran Sulfate Sodium (DSS)-induced colitis was established and hucMSC-Ex were administered to investigate their impact on the regulation of intestinal mast cells. An in vitro co-culture model using the human clonal colorectal adenocarcinoma cell line (Caco-2) and human mast cell line (LAD2) was also established for further exploration of the effect of hucMSC-Ex.

RESULTS

We observed the accumulation of mast cells in the intestines of patients with IBD as well as mice. In colitis mice, there was an upregulation of mast cell-related tryptase, interleukin-33 (IL-33), and suppression of tumorigenicity 2 receptor (ST2 or IL1RL1), and the function of the intestinal mucosal barrier related to intestinal tight junction protein was weakened. HucMSC-Ex treatment significantly reduced mast cell infiltration and intestinal damage. In the co-culture model, a substantial number of mast cells interact with the epithelial barrier, triggering activation of the IL-33/IL1RL1 (ST2) pathway and subsequent release of inflammatory factors and trypsin. This disruption leads to aberrant expression of tight junction proteins, which can be alleviated by supplementation with hucMSC-Ex.

CONCLUSION

Our results suggest that hucMSC-Ex may reduce the release of mast cell mediators via the IL-33/IL1RL1 (ST2) axis, thereby mitigating its detrimental effects on intestinal barrier function.

Sarcopenia and Dinapenia in Patients with Ulcerative Colitis (Cross-Sectional Observational Study)

Background. Sarcopenia is a generalised, progressive decline in skeletal muscle mass, strength and performance leading to reduced quality of life, increased risk of falls, hospitalisation and mortality. Primary sarcopenia results from age-related changes in muscle tissue. In certain cases, sarcopenia develops secondary as a consequence of diseases including ulcerative colitis (UC), which is associated with a systemic inflammatory process, malabsorption syndrome, restriction of patients’ physical activity and nutrient deficiencies. The term “dynapenia” or “probable sarcopenia” has been proposed to describe the decrease in muscle strength. Studies have demonstrated that muscle strength is a more relevant marker for predicting adverse outcomes because its measurement is more practical, whereas muscle mass is technically difficult to measure. Aims — to increase the effectiveness of the diagnosis of dinapenia, to assess the prevalence and risk factors of its formation in patients with UC. Methods. A single-centre, observational cross-sectional study included 80 UC patients. To identify factors associated with the development of dinapenia, patients with dinapenia were compared with patients without dinapenia. The investigated parameters in patients: sex, age, body mass index, peculiarities of the course of the disease, ongoing treatment, concomitant pathology, peculiarities of nutrition, nutritional deficiency, malabsorption syndrome, bad habits, psychological stress and sleep duration, physical activity, laboratory indicators of inflammation, myokine-adipokine profile. Statistical parameters were calculated using Statistica 10.0.1011.0 programme. Results. Dinapenia is present in 32.5% of UC patients. Risk factors for the formation of dinapenia in UC patients include female sex (p = 0.0003); nutritional insufficiency (p = 0.021); low physical activity (p = 0.010); artificial feeding in infancy (p = 0.024); inflammation, namely C-reactive protein, autoantibodies of class G against double-stranded DNA (p = 0.006; p = 0.002 respectively). Patients with UC with dinapenia significantly more often gave a positive answer to the questionnaire question “Does daily activity cause you a lot of stress?” (p = 0.048). In the group of UC patients with dinapenia, the level of cortisol in evening saliva was significantly higher than in the comparison group (p = 0.005). Conclusions. Sarcopenia and UC are multifactorial conditions with common developmental mechanisms that can burden each other. Dynamometry is not technically difficult and is justified from an economic point of view. The timely detection of dinapenia and its correction will additionally affect the mechanisms of UC pathogenesis in order to improve the quality of life and prognosis of patients.

Exploring environmental exposomes and the gut-brain nexus: Unveiling the impact of pesticide exposure

This review delves into the escalating concern of environmental pollutants and their profound impact on human health in the context of the modern surge in global diseases. The utilisation of chemicals in food production, which results in residues in food, has emerged as a major concern nowadays. By exploring the intricate relationship between environmental pollutants and gut microbiota, the study reveals a dynamic bidirectional interplay, as modifying microbiota profile influences metabolic pathways and subsequent brain functions. This review will first provide an overview of potential exposomes and their effect to gut health. This paper is then emphasis the connection of gut brain function by analysing microbiome markers with neurotoxicity responses. We then take pesticide as example of exposome to elucidate their influence to biomarkers biosynthesis pathways and subsequent brain functions. The interconnection between neuroendocrine and neuromodulators elements and the gut-brain axis emerges as a pivotal factor in regulating mental health and brain development. Thus, manipulation of gut microbiota function at the onset of stress may offer a potential avenue for the prevention and treatment for mental disorder and other neurodegenerative illness.

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.