Gut microbiota's effect on mental health: The gut-brain axis

Supplementation of L-glutamine enhanced mucosal immunity and improved hormonal status of combat-sport athletes

BACKGROUND

Maintaining proper immune function and hormone status is important for athletes to avoid upper respiratory tract infection (URTI) and insufficient recovery, which is detrimental to sport performance and health. The aim of this study was to evaluate whether three-week supplementation of L-glutamine could benefit the mucosal immunity and hormonal status of combat-sport athletes as well as their rates of upper respiratory tract infection (URTI) and subjective feelings of well-being after intensive training.

METHODS

Twenty-one combat-sport athletes from the National Taiwan University of Sport were recruited in this study. After intensive training, two groups of the participants were asked to consume powder form of 0.3 g/kg body weight of L-glutamine (GLU group) or maltodextrin (PLA group) with drinking water in a randomized design at the same time every day during 3 weeks. Saliva samples were collected to measure immunoglobulin A (IgA), nitric oxide (NO), testosterone (T) and cortisol (C) before and after three-week supplementation; moreover, Hooper's index questionnaires were completed for wellness assessment. The incidence and duration of URTI were recorded by using a health checklist throughout the entire study period.

RESULTS

Supplementation of L-glutamine significantly enhanced the concentrations of IgA and NO in saliva; additionally, the incidence of URTI was significantly reduced. Regarding hormones, T concentration was significantly decreased in the PLA group, whereas C concentration was significantly increased, resulting in a significant decrease of T/C ratio. In contrast, the GLU group showed a significant increase of T/C ratio, while the mood scores of the Hooper's index questionnaire were higher in the PLA group.

CONCLUSIONS

Three-week supplementation of L-glutamine after intensive training enhanced the mucosal immunity, improved hormonal status and reduced the rate of URTI of combat-sport athletes while feelings of well-being were also enhanced. Therefore, L-glutamine would be beneficial for the sports performance and recovery of athletes.

Contrasting the pharmacokinetic performance and gut microbiota effects of an amorphous solid dispersion and lipid nanoemulsion for a poorly water-soluble anti-psychotic

Increasing attention is being afforded to understanding the bidirectional relationship that exists between oral drugs and the gut microbiota. Often overlooked, however, is the impact that pharmaceutical excipients exert on the gut microbiota. Subsequently, in this study, we contrasted the pharmacokinetic performance and gut microbiota interactions between two commonly employed formulations for poorly soluble compounds, namely 1) an amorphous solid dispersion (ASD) stabilised by poly(vinyl pyrrolidone) K-30, and 2) a lipid nanoemulsion (LNE) comprised of medium chain glycerides and lecithin. The poorly soluble antipsychotic, lurasidone, was formulated with ASD and LNE due to its rate-limiting dissolution, poor oral bioavailability, and significant food effect. Both the ASD and LNE were shown to facilitate lurasidone supersaturation within in vitro dissolution studies simulating the gastrointestinal environment. This translated into profound improvements in oral pharmacokinetics in rats, with the ASD and LNE exerting comparable ∼ 2.5-fold improvements in lurasidone bioavailability, compared to the pure drug. The oral formulations imparted contrasting effects on the gut microbiota, with the LNE depleting the richness and abundance of the microbial ecosystem, as evidenced through reductions in alpha diversity (Chao1 index) and operational taxonomical units (OTUs). In contrast, the ASD exerted a 'gut neutral' effect, whereby a mild enrichment of alpha diversity and OTUs was observed. Importantly, this suggests that ASDs are effective solubility-enhancing formulations that can be used without comprising the integrity of the gut microbiota - an integral consideration in the treatment of mental health disorders, such as schizophrenia, due to the role of the gut microbiota in regulating mood and cognition.

Development of in vitro model of exosome transport in microfluidic gut-brain axis-on-a-chip

The gut communicates with the brain in a variety of ways known as the gut-brain axis (GBA), which is known to affect neurophysiological functions as well as neuronal disorders. Exosomes capable of passing through the blood-brain-barrier (BBB) have received attention as a mediator of gut-brain signaling and drug delivery vehicles. In conventional well plate-based experiments, it is difficult to observe the exosome movement in real time. Here, we developed a microfluidic-based GBA chip for co-culturing gut epithelial cells and neuronal cells and simultaneously observing exosome transport. The GBA-chip is aimed to mimic the in vivo situation of convective flow in blood vessels and convective and diffusive transport in the tissue interstitium. Here, fluorescence-labeled exosome was produced by transfection of HEK-293T cells with CD63-GFP plasmid. We observed in real time the secretion of CD63-GFP-exosomes by the transfected HEK-293T cells in the chip, and transport of the exosomes to neuronal cells and analyzed the dynamics of GFP-exosome movement. Our model is expected to enhance understanding of the roles of exosome in GBA.

Faecalibacterium prausnitzii, FOS and GOS loaded synbiotic reverses treatment-resistant depression in rats: Restoration of gut-brain crosstalk

Alterations in commensal gut microbiota, such as butyrate-producing bacteria and its metabolites, have been linked to stress-related brain disorders, including depression. Herein, we investigated the effect of Faecalibacterium prausnitzii (ATCC-27766) administered along with fructooligosaccharides (FOS) and galactooligosaccharides (GOS) in a rat model of treatment-resistant depression (TRD). The behavioral changes related to anxiety-, anhedonia- and despair-like phenotypes were recorded employing elevated plus maze, sucrose-preference test, and forced-swim test, respectively. Rats exposed to unpredictable chronic mild-stress (UCMS) and adrenocorticotropic hormone (ACTH) injections exhibited a TRD-like phenotype. Six-week administration of F. prausnitzii and FOS + GOS ameliorated TRD-like conditions in rats. This synbiotic treatment also restored the decreased levels of short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate in the fecal samples of TRD rats. Synbiotic-recipient TRD rats displayed an increased abundance of Lactobacillus helveticus, Lactobacillus hamsteri, and Ruminococcus flavefaciens. Moreover, more mucus-producing goblet cells were seen in the colon of synbiotic-treated rats, suggesting improved gut health. The synbiotic treatment effectively modulated neuroinflammation by reducing proinflammatory cytokines (IFN-γ, TNF-α, CRP, and IL-6). It normalized the altered levels of key neurotransmitters such as serotonin, gamma-aminobutyric acid, noradrenaline, and dopamine in the hippocampus and/or frontal cortex. The enhanced expression of brain-derived neurotrophic factor, tryptophan hydroxylase 1, and serotonin transporter-3 (SERT-3), and reduced levels of indoleamine 2,3-dioxygenase 1 (IDO-1) and kynurenine metabolite were observed in the synbiotic-treated group. We suggest that F. prausnitzii and FOS + GOS-loaded synbiotic may reverse the TRD-like symptoms in rats by positively impacting gut health, neuroinflammation, neurotransmitters, and gut microbial composition.

Probiotic Lactobacillus rhamnosus species: considerations for female reproduction and offspring health

Lactobacillus rhamnosus is a type of bacteria known as a probiotic and is often used to support the health of the digestive system and vaginal flora. This type of bacteria has an important role, showing positive effects on female reproductive biology, particularly by maintaining the balance of microorganisms in the vagina, reducing the risk of infection, and strengthening the immune system to support maternal health during pregnancy. There are also studies showing that these probiotics prevent maternal obesity and gestational diabetes. Consuming probiotics containing Lactobacillus rhamnosus strains may support the intestinal health of breastfeeding mothers, but they may also contribute to the health of offspring. Therefore, this review focuses on the current available data for examining the effects of Lactobacillus rhamnosus strains on female reproductive biology and offspring health. A systematic search was conducted in the PubMed and Web of Science databases from inception to May 2024. The search strategy was performed using keywords and MeSH (Medical Subject Headings) terms. Inconsistent ratings were resolved through discussion. This review is strengthened by multiple aspects of the methodological approach. The systematic search strategy, conducted by two independent reviewers, enabled the identification and evaluation of all relevant literature. Although there is a limited number of studies with high heterogeneity, current literature highlights the important contribution of Lactobacillus rhamnosus probiotics in enhancing female reproductive health and fertility. Furthermore, the probiotic bacteria in breast milk may also support the intestinal health of newborn, strengthen the immune system, and protect them against diseases at later ages.

Gut Microbiota and DTI Microstructural Brain Alterations in Rodents Due to Morphine Self-Administration

The opioid epidemic is an evolving health crisis in need of interventions that target all domains of maladaptive changes due to chronic use and abuse. Opioids are known for their effects on the opioid and dopaminergic systems, in addition to neurocircuitry changes that mediate changes in behavior; however, new research lines are looking at complementary changes in the brain and gut. The gut-brain axis (GBA) is a bidirectional signaling process that permits feedback between the brain and gut and is altered in subjects with opioid use disorders. In this work, we determine longitudinal, non-invasive, and in-vivo complementary changes in the brain and gut in rodents trained to self-administer morphine for two weeks using MRI and 16S rDNA analysis of fecal matter. We assess the changes occurring during both an acute phase (early in the self-administration process, after two days of self-administration) and a chronic phase (late in the self-administration process, after two weeks of self-administration), with all measurements benchmarked against baseline (naïve, non-drug state). Rats were surgically implanted with an intravenous jugular catheter for self-administration of morphine. Rats were allowed to choose between an active lever, which delivers a single infusion of morphine (0.4 mg/kg/infusion), or an inactive lever, which had no consequence upon pressing. Animals were scanned in a 7T MRI scanner three times (baseline, acute, and chronic), and before scanning, fecal matter was collected from each rat. After the last scan session, a subset of animals was euthanized, and brains were preserved for immunohistochemistry analysis. We found early changes in gut microbiota diversity and specific abundance as early as the acute phase that persisted into the chronic phase. In MRI, we identified alterations in diffusivity indices both within subjects and between groups, showing a main effect in the striatum, thalamus, and somatosensory cortex. Finally, immunohistochemistry analyses revealed increased neuroinflammatory markers in the thalamus of rats exposed to morphine. Overall, we demonstrate that morphine self-administration shapes the brain and gut microbiota. In conclusion, gut changes precede the anatomical effects observed in MRI features, with neuroinflammation emerging as a crucial link mediating communication between the gut and the brain. This highlights neuroinflammation as a potential target in addressing the impacts of opioid use.

Effects of Physical Exercise on the Microbiota in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder characterized by abdominal pain, bloating, diarrhea, and constipation. Recent studies have underscored the significant role of the gut microbiota in the pathogenesis of IBS. Physical exercise, as a non-pharmacological intervention, has been proposed to alleviate IBS symptoms by modulating the gut microbiota. Aerobic exercise, such as running, swimming, and cycling, has been shown to enhance the diversity and abundance of beneficial gut bacteria, including Lactobacillus and Bifidobacterium. These bacteria produce short-chain fatty acids that possess anti-inflammatory properties and support gut barrier integrity. Studies involving IBS patients participating in structured aerobic exercise programs have reported significant improvements in their gut microbiota's composition and diversity, alongside an alleviation of symptoms like abdominal pain and bloating. Additionally, exercise positively influences mental health by reducing stress and improving mood, which can further relieve IBS symptoms via the gut-brain axis. Long-term exercise interventions provide sustained benefits, maintaining the gut microbiota's diversity and stability, supporting immune functions, and reducing systemic inflammation. However, exercise programs must be tailored to individual needs to avoid exacerbating IBS symptoms. Personalized exercise plans starting with low-to-moderate intensity and gradually increasing in intensity can maximize the benefits and minimize risks. This review examines the impact of various types and intensities of physical exercise on the gut microbiota in IBS patients, highlighting the need for further studies to explore optimal exercise protocols. Future research should include larger sample sizes, longer follow-up periods, and examine the synergistic effects of exercise and other lifestyle modifications. Integrating physical exercise into comprehensive IBS management plans can enhance symptom control and improve patients' quality of life.

Identifying Future Study Designs and Indicators for Somatic Health Associated with Diets of Cohorts Living in Eco-Regions: Findings from the INSUM Expert Workshop

Diets, but also overall food environments, comprise a variety of significant factors with direct and indirect impacts on human health. Eco-Regions are geographical areas with a territorial approach to rural development, utilizing organic food and farming practices, and principles and promoting sustainable communities and food systems. However, so far, little attention has been given to quantifying aspects of the health of citizens living in these sustainable transition territories. The project "Indicators for Assessment of Health Effects of Consumption of Sustainable, Organic School Meals in Eco-Regions" (INSUM) aims to identify and discuss research approaches and indicators that could be applied to effectively measure the somatic, mental, and social health dimensions of citizens in Eco-Regions, linked to the intake of organic foods in their diets. In this paper, we focus on the somatic (physical) health dimension. A two-day workshop was held to discuss suitable methodology with an interdisciplinary, international group of experts. The results showed the limitations of commonly used tools for measuring dietary intake (e.g., relying on the memory of participants), and nutritional biomarkers (e.g., variations in correlations with specific intakes) for research understanding dietary intake and the health effects of diets. To investigate the complexity of this issue, the most suitable approach seems to be the combination of traditional markers of physical and mental health alongside emerging indicators such as the microbiome, nutrigenomics, metabolomics, or inflammatory biomarkers. Using new, digital, non-invasive, and wearable technologies to monitor indicators could complement future research. We conclude that future studies should adopt systemic, multidisciplinary approaches by combining not only indicators of somatic and mental health and social wellbeing (MHSW) but also considering the potential benefits of organic diets for health as well as aspects of sustainability connected to food environments.

Prevalence, demographic characteristics, and clinical features of suicide risk in first episode drug-naïve schizophrenia patients with comorbid severe anxiety

BACKGROUND

Both anxiety symptoms and suicide risk are common in schizophrenia. However, previous findings about the association between anxiety and suicide risk in schizophrenia were controversial. This study is the first to examine the prevalence of suicide risk and related demographic, clinical features in a large sample of first episode drug-naïve (FEDN) schizophrenia patients with comorbid severe anxiety.

METHODS

In total, 316 patients with FEDN schizophrenia were enrolled in this study. Patients' symptoms were assessed using the Hamilton Depression Scale (HAMD), Hamilton Anxiety Rating Scale (HAMA), and Positive and Negative Syndrome Scale (PANSS). Serum levels of glucose, insulin, uric acid, and lipids including total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), were evaluated.

RESULTS

In the current study, 56.3% patients presented comorbid severe anxiety. The rate of suicide risk was higher in the severe anxiety group (55.6%) than in the mild-moderate anxiety group (33.3%). The interactions among severe anxiety, uric acid and HDL-C were associated with suicide risk. Compared with patients with normal uric acid, those with abnormal uric acid exhibited a stronger association between HAMA scores and HAMD-suicide item scores. This enhanced association was also observed for patients with abnormal HDL-C levels.

CONCLUSIONS

In FEDN schizophrenia patients with comorbid severe anxiety, our findings suggested a high incidence of suicide risk. Abnormal levels of uric acid and low levels of HDL-C, as well as high depression may be associated with an increased risk of suicide in FEDN schizophrenia patients with comorbid severe anxiety.

Deciphering the gut microbiota's (Coprococcus and Subdoligranulum) impact on depression: Network pharmacology and molecular dynamics simulation

Depression, a prevalent mental health condition, significantly impacts global mental impairment rates. While antidepressants are commonly used, treatment-resistant depression (TRD) poses a challenge. Emerging research highlights the role of the gut microbiota in depression through the gut-brain axis. This study identifies key genes associated with depression influenced by specific gut microbiota, Coprococcus and Subdoligranulum. Using bioinformatics tools, potential targets were elucidated, and molecular docking studies were performed. Furthermore, gene expression analysis identified hub-genes related to depression, intersecting with metabolite targets. Protein-protein interaction analysis revealed pivotal targets such as PTGS2 and MMP9. Molecular docking demonstrated 3-Indolepropionic acid's superior affinity over (R)-3-(4-Hydroxyphenyl)lactate. Physicochemical properties and toxicity profiles were compared, suggesting favorable attributes for 3-Indolepropionic acid. Molecular dynamics simulations confirmed stability and interactions of compounds with target proteins. This comprehensive approach sheds light on the complex interplay between gut microbiota, genes, and depression, emphasizing the potential for microbiota-targeted interventions in mental health management.

The atypical antipsychotics lurasidone and olanzapine exert contrasting effects on the gut microbiome and metabolic function of rats

BACKGROUND AND PURPOSE

Antipsychotics such as olanzapine are associated with significant metabolic dysfunction, attributed to gut microbiome dysbiosis. A recent notion that most psychotropics are detrimental to the gut microbiome has arisen from consistent findings of metabolic adverse effects. However, unlike olanzapine, the metabolic effects of lurasidone are conflicting. Thus, this study investigates the contrasting effects of olanzapine and lurasidone on the gut microbiome to explore the hypothesis of 'gut neutrality' for lurasidone exposure.

EXPERIMENTAL APPROACH

Using Sprague-Dawley rats, the effects of olanzapine and lurasidone on the gut microbiome were explored. Faecal and blood samples were collected weekly over a 21-day period to analyse changes to the gut microbiome and related metabolic markers.

KEY RESULTS

Lurasidone triggered no significant weight gain or metabolic alterations, instead positively modulating the gut microbiome through increases in mean operational taxonomical units (OTUs) and alpha diversity. This novel finding suggests an underlying mechanism for lurasidone's metabolic inertia. In contrast, olanzapine triggered a statistically significant decrease in mean OTUs, substantial compositional variation and a depletion in short-chain fatty acid abundance. Microbiome depletion correlated with metabolic dysfunction, producing a 30% increase in weight gain, increased pro-inflammatory cytokine expression, and increased blood glycaemic and triglyceride levels.

CONCLUSION AND IMPLICATIONS

Our results challenge the notion that all antipsychotics disrupt the gut microbiome similarly and highlights the potential benefits of gut-neutral antipsychotics, such as lurasidone, in managing metabolic side effects. Further research is warranted to validate these findings in humans to guide personalised pharmacological treatment regimens for schizophrenia.

Probiotic Functions in Fermented Foods: Anti-Viral, Immunomodulatory, and Anti-Cancer Benefits

Fermented foods can provide many benefits to our health. These foods are created by the action of microorganisms and help support our digestive health and immune system. Fermented foods include yogurt, kimchi, pickles, kefir, beer, wine, and more. Fermented foods contain probiotics, lactic acid bacteria (LAB), yeast, organic acids, ethanol, or antimicrobial compounds, which help balance the gut microbiome and improve digestive health. Fermented foods can also benefit your overall health by increasing the diversity of your gut microbiome and reducing inflammation. By routinely consuming fermented foods with these benefits, we can continue to improve our health. Probiotics from fermented foods are beneficial strains of bacteria that are safe for human health and constitute an important component of human health, even for children and the elderly. Probiotics can have a positive impact on your health, especially by helping to balance your gut microbiome and improve digestive health. Probiotics can also boost your immune system and reduce inflammation, which can benefit your overall health. Probiotics, which can be consumed in the diet or in supplement form, are found in many different types of foods and beverages. Research is continuing to investigate the health effects of probiotics and how they can be utilized. The potential mechanisms of probiotics include anti-cancer activity, preventing and treating immune system-related diseases, and slowing the development of Alzheimer's disease and Huntington's disease. This is due to the gut-brain axis of probiotics, which provides a range of health benefits beyond the digestive and gastrointestinal systems. Probiotics reduce tumor necrosis factor-α and interleukins through the nuclear factor-kappa B and mitogen-activated protein kinase pathways. They have been shown to protect against colon cancer and colitis by interfering with the adhesion of harmful bacteria in the gut. This article is based on clinical and review studies identified in the electronic databases PubMed, Web of Science, Embase, and Google Scholar, and a systematic review of clinical studies was performed.

Defensins: Exploring Their Opposing Roles in Colorectal Cancer Progression

Colorectal cancer (CRC) represents a significant global healthcare burden, with a particularly concerning rising incidence among younger adults. This trend may highlight potential links between diet, gut microbiome, and CRC risk. Novel therapeutic options have been increasingly based on the understanding of molecular mechanisms and pathways. The PI3K/AKT/mTOR pathway, a crucial cell growth regulator, offers a promising target for CRC therapy. mTOR, a key component within this pathway, controls cell growth, survival, and metabolism. Understanding the specific roles of defensins, particularly human β-Defensin 1 (HBD-1), in CRC is crucial. HBD-1 exhibits potent antimicrobial activity and may influence CRC development. Deciphering defensin expression patterns in CRC holds the promise of improved understanding of tumorigenesis, which may pave the way for improved diagnostics and therapies. This article reviews recent advances in understanding regarding how HBD-1 influences CRC initiation and progression, highlighting the molecular mechanisms by which it impacts CRC. Further, we describe the interaction between defensins and mTOR pathway in CRC.

The Role of Probiotics in Skin Care: Advances, Challenges, and Future Needs

The skin, being the largest organ in the human body, plays a pivotal role in safeguarding the body against invasive pathogens. Therefore, it is essential to reinforce and protect this vital organ. Current research supports the impact of probiotics on skin health and their ability to alleviate various skin disorders. However, the effectiveness and probable side effects of probiotics in skin care remain a subject of debate, necessitating further investigation and analysis. Hence, this study aims to highlight existing gaps and future needs in the current research on probiotics in skin care and pave the way for future investigations. Therefore, we scrutinized the effects of oral (fermented foods and dietary supplements) and non-oral/topical probiotics on skin care, and the mechanism of probiotics that affect skin health. The results of most studies showed that fermented foods containing probiotics, particularly dairy products, positively impact skin health. The research results regarding the efficacy of probiotic supplements and live strains in treating skin disorders show promising potential. However, safety evaluations are crucial, to identify any potential adverse effects. While research has identified numerous potential mechanisms by which probiotics may influence skin health, a complete understanding of their precise mode of action remains elusive. However, it seems that probiotics can exert their positive effects through the gut-skin and gut-skin-brain axis on the human body. Therefore, following the identification of safe probiotics, additional studies should be carried out to establish optimal dosages, potential side effects, suitable regulatory guidelines, and validation methods.

Microbiota-brain axis: Exploring the role of gut microbiota in psychiatric disorders - A comprehensive review

Mental illness is a hidden epidemic in modern science that has gradually spread worldwide. According to estimates from the World Health Organization (WHO), approximately 10% of the world's population suffers from various mental diseases each year. Worldwide, financial and health burdens on society are increasing annually. Therefore, understanding the different factors that can influence mental illness is required to formulate novel and effective treatments and interventions to combat mental illness. Gut microbiota, consisting of diverse microbial communities residing in the gastrointestinal tract, exert profound effects on the central nervous system through the gut-brain axis. The gut-brain axis serves as a conduit for bidirectional communication between the two systems, enabling the gut microbiota to affect emotional and cognitive functions. Dysbiosis, or an imbalance in the gut microbiota, is associated with an increased susceptibility to mental health disorders and psychiatric illnesses. Gut microbiota is one of the most diverse and abundant groups of microbes that have been found to interact with the central nervous system and play important physiological functions in the human gut, thus greatly affecting the development of mental illnesses. The interaction between gut microbiota and mental health-related illnesses is a multifaceted and promising field of study. This review explores the mechanisms by which gut microbiota influences mental health, encompassing the modulation of neurotransmitter production, neuroinflammation, and integrity of the gut barrier. In addition, it emphasizes a thorough understanding of how the gut microbiome affects various psychiatric conditions.

From Skin and Gut to the Brain: The Infectious Journey of the Human Commensal Fungus Malassezia and Its Neurological Consequences

The human mycobiome encompasses diverse communities of fungal organisms residing within the body and has emerged as a critical player in shaping health and disease. While extensive research has focused on the skin and gut mycobiome, recent investigations have pointed toward the potential role of fungal organisms in neurological disorders. Among those fungal organisms, the presence of the commensal fungus Malassezia in the brain has created curiosity because of its commensal nature and primary association with the human skin and gut. This budding yeast is responsible for several diseases, such as Seborrheic dermatitis, Atopic dermatitis, Pityriasis versicolor, Malassezia folliculitis, dandruff, and others. However recent findings surprisingly show the presence of Malassezia DNA in the brain and have been linked to diseases like Alzheimer's disease, Parkinson's disease, Multiple sclerosis, and Amyotrophic lateral sclerosis. The exact role of Malassezia in these disorders is unknown, but its ability to infect human cells, travel through the bloodstream, cross the blood-brain barrier, and reside along with the lipid-rich neuronal cells are potential mechanisms responsible for pathogenesis. This also includes the induction of pro-inflammatory cytokines, disruption of the blood-brain barrier, gut-microbe interaction, and accumulation of metabolic changes in the brain environment. In this review, we discuss these key findings from studies linking Malassezia to neurological disorders, emphasizing the complex and multifaceted nature of these cases. Furthermore, we discuss potential mechanisms through which Malassezia might contribute to the development of neurological conditions. Future investigations will open up new avenues for our understanding of the fungal gut-brain axis and how it influences human behavior. Collaborative research efforts among microbiologists, neuroscientists, immunologists, and clinicians hold promise for unraveling the enigmatic connections between human commensal Malassezia and neurological disorders.

Current Approaches to Prevent or Reverse Microbiome Dysbiosis in Chronic Inflammatory Rheumatic Diseases

Advances in knowledge of the microbiome and its relationship with the immune system have led to a better understanding of the pathogenesis of chronic inflammatory rheumatic diseases (CIRD). Indeed, the microbiome dysbiosis now occupies a particular place with implications for the determinism and clinical expression of CIRD, as well as the therapeutic response of affected patients. Several approaches exist to limit the impact of the microbiome during CIRD. This review aimed to present current strategies to prevent or reverse microbiome dysbiosis based on existing knowledge, in order to provide practical information to healthcare professionals treating patients suffering from CIRD.

Enteric Nervous System Alterations in Inflammatory Bowel Disease: Perspectives and Implications

The enteric nervous system (ENS), consisting of neurons and glial cells, is situated along the gastrointestinal (GI) tract's wall and plays a crucial role in coordinating digestive processes. Recent research suggests that the optimal functioning of the GI system relies on intricate connections between the ENS, the intestinal epithelium, the immune system, the intestinal microbiome, and the central nervous system (CNS). Inflammatory bowel disease (IBD) encompasses a group of chronic inflammatory disorders, such as Crohn's disease (CD) and ulcerative colitis (UC), characterized by recurring inflammation and damage to the GI tract. This review explores emerging research in the dynamic field of IBD and sheds light on the potential role of ENS alterations in both the etiology and management of IBD. Specifically, we delve into IBD-induced enteric glial cell (EGC) activation and its implications for persistent enteric gliosis, elucidating how this activation disrupts GI function through alterations in the gut-brain axis (GBA). Additionally, we examine IBD-associated ENS alterations, focusing on EGC senescence and the acquisition of the senescence-associated secretory phenotype (SASP). We highlight the pivotal role of these changes in persistent GI inflammation and the recurrence of IBD. Finally, we discuss potential therapeutic interventions involving senotherapeutic agents, providing insights into potential avenues for managing IBD by targeting ENS-related mechanisms. This approach might represent a potential alternative to managing IBD and advance treatment of this multifaceted disease.

Harnessing the Health and Techno-Functional Potential of Lactic Acid Bacteria: A Comprehensive Review

This review examines the techno-functional properties of lactic acid bacteria (LABs) in the food industry, focusing on their potential health benefits. We discuss current findings related to the techno-functionality of LAB, which includes acidification, proteolytic and lipolytic features, and a variety of other biochemical activities. These activities include the production of antimicrobial compounds and the synthesis of exopolysaccharides that improve food safety and consumer sensory experience. LABs are also known for their antioxidant abilities, which help reduce oxidative reactions in foods and improve their functional properties. In addition, LABs' role as probiotics is known for their promising effects on gut health, immune system modulation, cholesterol control, and general wellbeing. Despite these advantages, several challenges hinder the effective production and use of probiotic LABs, such as maintaining strain viability during storage and transport as well as ensuring their efficacy in the gastrointestinal tract. Our review identifies these critical barriers and suggests avenues for future research.

A comprehensive review on the pharmacological role of gut microbiome in neurodegenerative disorders: potential therapeutic targets

Neurological disorders, including Alzheimer and Parkinson's, pose significant challenges to public health due to their complex etiologies and limited treatment options. Recent advances in research have highlighted the intricate bidirectional communication between the gut microbiome and the central nervous system (CNS), revealing a potential therapeutic avenue for neurological disorders. Thus, this review aims to summarize the current understanding of the pharmacological role of gut microbiome in neurological disorders. Mounting evidence suggests that the gut microbiome plays a crucial role in modulating CNS function through various mechanisms, including the production of neurotransmitters, neuroactive metabolites, and immune system modulation. Dysbiosis, characterized by alterations in gut microbial composition and function, has been observed in many neurological disorders, indicating a potential causative or contributory role. Pharmacological interventions targeting the gut microbiome have emerged as promising therapeutic strategies for neurological disorders. Probiotics, prebiotics, antibiotics, and microbial metabolite-based interventions have shown beneficial effects in animal models and some human studies. These interventions aim to restore microbial homeostasis, enhance microbial diversity, and promote the production of beneficial metabolites. However, several challenges remain, including the need for standardized protocols, identification of specific microbial signatures associated with different neurological disorders, and understanding the precise mechanisms underlying gut-brain communication. Further research is necessary to unravel the intricate interactions between the gut microbiome and the CNS and to develop targeted pharmacological interventions for neurological disorders.

Oral exposure to food grade titanium dioxide (E171) induces intestinal and behavioural alterations in adult mice but limited effects in young mice

BACKGROUND

Food-grade titanium dioxide (E171), a white colourant widely used in ultra-processed food products, has been banned in the European Union. However, its usage is still permitted in medicines, and in several other countries. The estimated intake of E171 in children is higher than in adults, which led us to hypothesise that E171 induces differential effects depending on age, with adult mice being the most susceptible due to age, despite the lower dose.

AIM

To evaluate the effects of oral administration of E171 on intestinal permeability, ileum, and colon histology, and how these effects impact anxious and depressive behaviour in young and adult mice of both sexes.

METHODS

Young and adult mice of both sexes C57BL/6 mice received 10 mg/kgbw E171/3 times per week for 3 months. E171 was administered orally in water by pipetting, while control groups only received drinking water, then intestinal permeability, histology and animal behaviour were analysed.

RESULTS

E171 showed an amorphous shape, primary particles sized below 1 µm and anatase crystalline structure. Oral administration of E171 disrupted the intestinal permeability in adult male and female mice, but no effects were observed in young mice of both sexes. E171 promoted ileal adenoma formation in half of the adult female population, moreover hyperplastic crypts, and hyperplastic goblet cells at histological level in adult mice of both sexes. The colon presented hyperplastic goblet cells, hyperchromatic nuclei, increased proliferation and DNA damage in adult mice of both sexes. The anxiety and depressive behaviour were only altered in adult mice treated with E171, but no changes were detected in young animals of both sexes.

CONCLUSIONS

Adult mice displayed higher susceptibility in all parameters analysed in this study compared to young mice of both sexes.

Combination of vitamin D3 and fructooligosaccharides upregulates colonic vitamin D receptor in C57BL/6J mice and affects anxiety-related behavior in a sex-specific manner

Depression and anxiety disorders are among the most common mental health disorders that affect US adults today, frequently related to vitamin D (VD) insufficiency. Along with VD, growing evidence suggests gut microbiota likely play a role in neuropsychiatric disorders. Here, we investigated if modulation of gut microbiota would disrupt host VD status and promote behaviors related to depression and anxiety in adult mice. Six-week-old male and female C57BL/6J mice (n = 10/mice/group) were randomly assigned to receive (1) control diet (CTR), control diet treated with antibiotics (AB), control diet with total 5000 IU of VD (VD), VD treated with antibiotics (VD + AB), VD supplemented with 5% w/w fructooligosaccharides (FOS; VF), and VF diet treated with antibiotics (VF + AB), respectively, for 8 weeks. Our study demonstrated that VD status was not affected by antibiotic regimen. VD alone ameliorates anxiety-related behavior in female mice, and that combination with FOS (i.e., VF) did not further improve the outcome. Male mice, in contrast, exhibit greater anxiety with VF, but not VD, when compared with CTR mice. Colonic VD receptor was elevated in VF-treated mice in both sexes, compared with CTR, which was positively correlated to colonic TPH1, a rate-limiting enzyme for serotonin synthesis. Taken together, our data indicate that the effect of VF on anxiety-related behavior is sex-specific, which may partially be attributed to the activation of colonic VD signaling and subsequent serotonin synthesis. The synergistic or additive effect of VD and FOS on mood disorders remained to be investigated.

Gut Microbiota Profiles in Myopes and Nonmyopes

Purpose

To identify compositional differences in the gut microbiome of nonmyopes (NM) and myopes using 16S ribosomal RNA sequencing and to investigate whether the microbiome may contribute to the onset or progression of the condition.

Methods

Faecal samples were collected from 52 adult participants, of whom 23 were NM, 8 were progressive myopes (PM), and 21 were stable myopes (SM). The composition of the gut microbiota in each group was analysed using 16S ribosomal RNA gene sequencing.

Results

There were no significant differences in alpha and beta diversity between the three groups (NM, PM, and SM). However, the distributions of Bifidobacterium, Bacteroides, Megamonas, Faecalibacterium, Coprococcus, Dorea, Roseburia, and Blautia were significantly higher in the myopes (SM and PM combined) when compared with emmetropes. The myopes exhibited significantly greater abundance of bacteria that are linked to the regulation of dopaminergic signalling, such as Clostridium, Ruminococcus, Bifidobacterium, and Bacteroides. Individuals with stable myopia were found to have a significantly higher proportion of Prevotella copri than those with progressive myopia. Bifidobacterium adolescentis, a gamma-aminobutyric acid (GABA)-producing bacterium, was significantly higher in all myopes than in NM and, in the comparison between SM and PM, it is significantly higher in SM. B. uniformis and B. fragilis, both GABA-producing Bacteroides, were present in relatively high abundance in all myopes and in SM compared with PM, respectively.

Conclusions

The presence of bacteria related to dopamine effect and GABA-producing bacteria in the gut microbiome of myopes may suggest a role of these microorganisms in the onset and progression of myopia.

The role of cognitive emotion regulation strategies in predicting the resilience, symptom severity, and quality of life of patients with irritable bowel syndrome

BACKGROUND

Psychosocial stressors contribute to the development of irritable bowel syndrome (IBS) and exacerbate the symptoms. The capability to cope with stress is an essential element in the management of IBS. This study assessed nine cognitive emotion regulation strategies (CERS) and their role in predicting symptom severity, quality of life (QOL), and resilience in IBS subjects.

METHODS

The scores regarding nine subscales of CERS were obtained by cognitive emotion regulation questionnaire (CERQ) and compared between study patients based on the severity and subtypes of IBS using one-way ANOVA. To evaluate the predictive role of CERS, logistic regression was performed. The correlation between CERS and the QOL was assessed by Pearson correlation analysis. The score of resilience was measured by Connor-Davidson Resilience Scale (CD-RISC).

RESULTS

We recruited 100 patients diagnosed with IBS based on ROME IV criteria. Among nine subscales of CERS, patients with more severe symptoms scored higher in catastrophizing (p < 0.001) and blaming others (p = 0.015) while lower in positive reappraisal (p = 0.028). Blaming others was the only predictor of resilience and severity of IBS in our patients (odds ratio (OR): -2.103, p=0.028, and OR:1.715, p = 0.049, respectively). We observed significant negative correlations between the quality of life and rumination (r= -0.202, p=0.044), self-blame (r= -0.241, p=0.016), catastrophizing (r= -0.342, p<0.001), and blaming others (r= -0.219, p=0.028).

CONCLUSION

Maladaptive strategies are more common in IBS patients with more severe symptoms and have negative correlations with the QOL. Blaming others has the potential to predict the resilience and severity of symptoms in IBS patients.

Nutraceuticals in Psychiatric Disorders: A Systematic Review

Correct nutrition and diet are directly correlated with mental health, functions of the immune system, and gut microbiota composition. Diets with a high content of some nutrients, such as fibers, phytochemicals, and short-chain fatty acids (omega-3 fatty acids), seem to have an anti-inflammatory and protective action on the nervous system. Among nutraceuticals, supplementation of probiotics and omega-3 fatty acids plays a role in improving symptoms of several mental disorders. In this review, we collect data on the efficacy of nutraceuticals in patients with schizophrenia, autism spectrum disorders, major depression, bipolar disorder, and personality disorders. This narrative review aims to provide an overview of recent evidence obtained on this topic, pointing out the direction for future research.

Hormetic Nutrition and Redox Regulation in Gut-Brain Axis Disorders

The antioxidant and anti-inflammatory effects of hormetic nutrition for enhancing stress resilience and overall human health have received much attention. Recently, the gut-brain axis has attracted prominent interest for preventing and therapeutically impacting neuropathologies and gastrointestinal diseases. Polyphenols and polyphenol-combined nanoparticles in synergy with probiotics have shown to improve gut bioavailability and blood-brain barrier (BBB) permeability, thus inhibiting the oxidative stress, metabolic dysfunction and inflammation linked to gut dysbiosis and ultimately the onset and progression of central nervous system (CNS) disorders. In accordance with hormesis, polyphenols display biphasic dose-response effects by activating at a low dose the Nrf2 pathway resulting in the upregulation of antioxidant vitagenes, as in the case of heme oxygenase-1 upregulated by hidrox® or curcumin and sirtuin-1 activated by resveratrol to inhibit reactive oxygen species (ROS) overproduction, microbiota dysfunction and neurotoxic damage. Importantly, modulation of the composition and function of the gut microbiota through polyphenols and/or probiotics enhances the abundance of beneficial bacteria and can prevent and treat Alzheimer's disease and other neurological disorders. Interestingly, dysregulation of the Nrf2 pathway in the gut and the brain can exacerbate selective susceptibility under neuroinflammatory conditions to CNS disorders due to the high vulnerability of vagal sensory neurons to oxidative stress. Herein, we aimed to discuss hormetic nutrients, including polyphenols and/or probiotics, targeting the Nrf2 pathway and vitagenes for the development of promising neuroprotective and therapeutic strategies to suppress oxidative stress, inflammation and microbiota deregulation, and consequently improve cognitive performance and brain health. In this review, we also explore interactions of the gut-brain axis based on sophisticated and cutting-edge technologies for novel anti-neuroinflammatory approaches and personalized nutritional therapies.

Neuroactive metabolites and bile acids are altered in extremely premature infants with brain injury

The gut microbiome is associated with pathological neurophysiological evolvement in extremely premature infants suffering from brain injury. The exact underlying mechanism and its associated metabolic signatures in infants are not fully understood. To decipher metabolite profiles linked to neonatal brain injury, we investigate the fecal and plasma metabolome of samples obtained from a cohort of 51 extremely premature infants at several time points, using liquid chromatography (LC)-high-resolution mass spectrometry (MS)-based untargeted metabolomics and LC-MS/MS-based targeted analysis for investigating bile acids and amidated bile acid conjugates. The data are integrated with 16S rRNA gene amplicon gut microbiome profiles as well as patient cytokine, growth factor, and T cell profiles. We find an early onset of differentiation in neuroactive metabolites between infants with and without brain injury. We detect several bacterially derived bile acid amino acid conjugates in plasma and feces. These results provide insights into the early-life metabolome of extremely premature infants.

Current iron therapy in the light of regulation, intestinal microbiome, and toxicity: are we prescribing too much iron?

Iron deficiency is a widespread global health concern with varying prevalence rates across different regions. In developing countries, scarcity of food and chronic infections contribute to iron deficiency, while in industrialized nations, reduced food intake and dietary preferences affect iron status. Other causes that can lead to iron deficiency are conditions and diseases that result in reduced intestinal iron absorption and blood loss. In addition, iron absorption and its bioavailability are influenced by the composition of the diet. Individuals with increased iron needs, including infants, adolescents, and athletes, are particularly vulnerable to deficiency. Severe iron deficiency can lead to anemia with performance intolerance or shortness of breath. In addition, even without anemia, iron deficiency leads to mental and physical fatigue, which points to the fundamental biological importance of iron, especially in mitochondrial function and the respiratory chain. Standard oral iron supplementation often results in gastrointestinal side effects and poor compliance. Low-dose iron therapy seems to be a valid and reasonable therapeutic option due to reduced hepatic hepcidin formation, facilitating efficient iron resorption, replenishment of iron storage, and causing significantly fewer side effects. Elevated iron levels influence gut microbiota composition, favoring pathogenic bacteria and potentially disrupting metabolic and immune functions. Protective bacteria, such as bifidobacteria and lactobacilli, are particularly susceptible to increased iron levels. Dysbiosis resulting from iron supplementation may contribute to gastrointestinal disorders, inflammatory bowel disease, and metabolic disturbances. Furthermore, gut microbiota alterations have been linked to mental health issues. Future iron therapy should consider low-dose supplementation to mitigate adverse effects and the impact on the gut microbiome. A comprehensive understanding of the interplay between iron intake, gut microbiota, and human health is crucial for optimizing therapeutic approaches and minimizing potential risks associated with iron supplementation.

The Role of Gut Microbiota, Nutrition, and Physical Activity in Depression and Obesity-Interdependent Mechanisms/Co-Occurrence

Obesity and depression are interdependent pathological disorders with strong inflammatory effects commonly found worldwide. They determine the health status of the population and cause key problems in terms of morbidity and mortality. The role of gut microbiota and its composition in the treatment of obesity and psychological factors is increasingly emphasized. Published research suggests that prebiotic, probiotic, or symbiotic preparations can effectively intervene in obesity treatment and mood-dysregulation alleviation. Thus, this literature review aims to highlight the role of intestinal microbiota in treating depression and obesity. An additional purpose is to indicate probiotics, including psychobiotics and prebiotics, potentially beneficial in supporting the treatment of these two diseases.

The effect of microbiome therapy on COVID-19-induced gut dysbiosis: A narrative and systematic review

AIMS

Emerging evidence highlights the role of COVID-19 in instigating gut dysbiosis, with repercussions on disease severity and bidirectional gut-organ communication involving the lung, heart, brain, and liver. This study aims to evaluate the efficacy of probiotics, prebiotics, synbiotics, and fecal microbiota transplantation (FMT) in addressing gut dysbiosis associated with COVID-19, as well as their impact on related disease severity and clinical outcomes.

MATERIALS AND METHODS

We systematically review 27 studies exploring the efficacy of different microbiome-modulating therapies: probiotics, prebiotics, synbiotics, and fecal microbiota transplantation as potential interventions for COVID-19.

KEY FINDINGS

The probiotics and synbiotics investigated encompassed a spectrum of eight bacterial and fungal genera, namely Lactobacillus, Bifidobacterium, Streptococcus, Enterococcus, Pediococcus, Bacillus, Saccharomyces, and Kluyveromyces. Noteworthy prebiotics employed in these studies included chestnut tannin, galactooligosaccharides, fructooligosaccharides, xylooligosaccharide, and resistant dextrin. The majority of the investigated biotics exhibited positive effects on COVID-19 patients, manifesting in symptom alleviation, inflammation reduction, and notable decreases in mortality rates. Five studies reported death rates, showing an average mortality ranging from 0 % to 11 % in the intervention groups, as compared to 3 % to 30 % in the control groups. Specifically, probiotics, prebiotics, and synbiotics demonstrated efficacy in diminishing the duration and severity of symptoms while significantly accelerating viral and symptomatic remission. FMT emerged as a particularly effective strategy, successfully restoring gut microbiota and ameliorating gastrointestinal disorders.

SIGNIFICANCE

The insights gleaned from this review significantly contribute to our broader comprehension of the therapeutic potential of biotics in addressing COVID-19-related gut dysbiosis and mitigating secondary multi-organ complications.

Risk of Anxiety, Depression, and Attention-Deficit/Hyperactivity Disorder in Pediatric Patients With Inflammatory Bowel Disease: A Population-Based Cohort Study

INTRODUCTION

Inflammatory bowel disease (IBD) is associated with depression and anxiety in adults, but data are scarce on risk of psychiatric diseases in children with IBD. We aimed to estimate the risk of anxiety, depression, or attention-deficit/hyperactivity disorder (ADHD) in patients with pediatric-onset IBD.

METHODS

We performed a nationwide, register-based cohort study including all patients with pediatric-onset IBD diagnosed in Denmark during 1998-2018, resulting in 3,559 patients matched 1:5 on age, sex, municipality of residence, and time period, resulting in 17,795 reference individuals. We used Cox regression to calculate hazard ratios for each outcome after a diagnosis with IBD.

RESULTS

Patients with pediatric-onset IBD had an increased risk of depression (hazard ratio [HR] 1.50; 95% confidence interval [CI] 1.26-1.80) and of using antidepressants (HR, 1.54; 95% CI, 1.39-1.71) and, surprisingly, a reduced risk of using methylphenidate (HR, 0.75; 95% CI, 0.58-0.98). Patients with both IBD subtypes (Crohn's disease and ulcerative colitis) had an increased risk of using antidepressants and developing depression, which was particularly high in patients with Crohn's disease (HR, 1.73; 95% CI, 1.35-2.22). Patients with ulcerative colitis had reduced risk of using methylphenidate (HR, 0.63; 95% CI, 0.43-0.93) and a reduced-although not statistically significant-risk of being diagnosed with ADHD compared with the background population.

DISCUSSION

Patients with pediatric-onset IBD have a 50% increased risk of developing depression, which is important for healthcare providers to be aware of and manage. Remarkably, we found a reduced risk of receiving methylphenidate and being diagnosed with ADHD, which merits further investigation.

The gastrointestinal microbiota in the development of ME/CFS: a critical view and potential perspectives

Like other infections, a SARS-CoV-2 infection can also trigger Post-Acute Infection Syndromes (PAIS), which often progress into myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). ME/CFS, characterized by post-exercise malaise (PEM), is a severe multisystemic disease for which specific diagnostic markers or therapeutic concepts have not been established. Despite numerous indications of post-infectious neurological, immunological, endocrinal, and metabolic deviations, the exact causes and pathophysiology remain unclear. To date, there is a paucity of data, that changes in the composition and function of the gastrointestinal microbiota have emerged as a potential influencing variable associated with immunological and inflammatory pathways, shifts in ME/CFS. It is postulated that this dysbiosis may lead to intestinal barrier dysfunction, translocation of microbial components with increased oxidative stress, and the development or progression of ME/CFS. In this review, we detailed discuss the findings regarding alterations in the gastrointestinal microbiota and its microbial mediators in ME/CFS. When viewed critically, there is currently no evidence indicating causality between changes in the microbiota and the development of ME/CFS. Most studies describe associations within poorly defined patient populations, often combining various clinical presentations, such as irritable bowel syndrome and fatigue associated with ME/CFS. Nevertheless, drawing on analogies with other gastrointestinal diseases, there is potential to develop strategies aimed at modulating the gut microbiota and/or its metabolites as potential treatments for ME/CFS and other PAIS. These strategies should be further investigated in clinical trials.

Neuroprotective effects of probiotics on anxiety- and depression-like disorders in stressed mice by modulating tryptophan metabolism and the gut microbiota

Anxiety- and depression-like behaviors are commonly observed clinical features of depression and many other mental disorders. Recent evidence has revealed the crucial role of the microbiota-gut-brain axis in the bidirectional communication between the gastrointestinal tract and the central nervous system. Supplementation with psychobiotics may provide a novel approach for the adjunctive treatment of mental disorders by regulating the intestinal microecology. We isolated and identified a novel probiotic, Lactiplantibacillus plantarum D-9 (D-9), from traditional Chinese fermented foods in our previous work, which exhibited a high yield of gamma-aminobutyric acid (GABA). Herein, it was proved that the oral administration of D-9 could alleviate the depression- and anxiety-like behaviors of Chronic Unpredicted Mild Stress (CUMS) mice, and show non-toxicity or side-effects in the mice. Physiological and biochemical analyses demonstrated that D-9 regulated tryptophan metabolism, the HPA-axis and inflammation in CUMS mice. Moreover, D-9 modulated the structure and composition of the gut microbiota, leading to an increase in the relative abundance of Ligilactobacillus murinus and Lactobacillus johnsonii, and a decrease in the levels of Kineothrix alysoides and Helicobacter bilis compared to those in CUMS mice. Our work demonstrates that D-9 alleviated anxiety- and depression-like disorders in CUMS mice by modulating tryptophan metabolism and the gut microbiota. These findings provide an innovative strategy for the intervention and treatment of depressive disorders.

Impact of evolution on lifestyle in microbiome

This chapter analyses the interaction between microbiota and humans from an evolutionary point of view. Long-term interactions between gut microbiota and host have been generated as a result of dietary choices through coevolutionary processes, where mutuality of advantage is essential. Likewise, the characteristics of the intestinal environment have made it possible to describe different intrahost evolutionary mechanisms affecting microbiota. For its part, the intestinal microbiota has been of great importance in the evolution of mammals, allowing the diversification of dietary niches, phenotypic plasticity and the selection of host phenotypes. Although the origin of the human intestinal microbial community is still not known with certainty, mother-offspring transmission plays a key role, and it seems that transmissibility between individuals in adulthood also has important implications. Finally, it should be noted that certain aspects inherent to modern lifestyle, including refined diets, antibiotic intake, exposure to air pollutants, microplastics, and stress, could negatively affect the diversity and composition of our gut microbiota. This chapter aims to combine current knowledge to provide a comprehensive view of the interaction between microbiota and humans throughout evolution.

Gut dysbiosis and neurological modalities: An engineering approach via proteomic analysis of gut-brain axis

The human gut microbiota is a complex and dynamic community of microorganisms, that influence metabolic, neurodevelopmental, and immune pathways. Microbial dysbiosis, characterized by changes in microbial diversity and relative abundances, is implicated in the development of various chronic neurological and neurodegenerative disorders. These disorders are marked by the accumulation of pathological protein aggregates, leading to the progressive loss of neurons and behavioural functions. Dysregulations in protein-protein interaction networks and signalling complexes, critical for normal brain function, are common in neurological disorders but challenging to unravel, particularly at the neuron and synapse-specific levels. To advance therapeutic strategies, a deeper understanding of neuropathogenesis, especially during the progressive disease phase, is needed. Biomarkers play a crucial role in identifying disease pathophysiology and monitoring disease progression. Proteomics, a powerful technology, shows promise in accelerating biomarker discovery and aiding in the development of novel treatments. In this chapter, we provide an in-depth overview of how proteomic techniques, utilizing various biofluid samples from patients with neurological conditions and diverse animal models, have contributed valuable insights into the pathogenesis of numerous neurological disorders. We also discuss the current state of research, potential challenges, and future directions in proteomic approaches to unravel neuro-pathological conditions.

The role of vitamin D in depression and anxiety disorders: a review of the literature

BACKGROUND

Prevalence of mental health disorders continue to increase worldwide. Over the past decades, suboptimal vitamin D (VD) levels and gut dysbiosis have been associated with neurological dysfunction and psychiatric disorders.

METHODS

In this review, we examined the available literature on VD and mental health disorders, particularly depression and anxiety, in both clinical and pre-clinical studies.

RESULTS

Our extensive review failed to find a link between VD deficiency, depression, and anxiety-related behavior in preclinical animal models. However, strong evidence suggests that VD supplementation may alleviate symptoms in chronically stressed rodents, with some promising evidence from clinical studies. Further, fecal microbiota transplantations suggest a potential role of gut microbiota in neuropsychiatric disorders, although the underlying mechanisms remain to be fully elucidated. It has been postulated that serotonin, primarily produced by gut bacteria, may be a crucial factor. Hence, whether VD has the ability to impact gut microbiota and modulate serotonin synthesis warrants further investigation.

CONCLUSIONS

Taken together, literature has suggested that VD may serve as a key regulator in the gut-brain axis to modulate gut microbiota and alleviate symptoms of depression and anxiety. The inconsistent results of VD supplementation in clinical studies, particularly among VD deficient participants, suggests that current intake recommendations may need to be re-evaluated for individuals at-risk (i.e. prior to diagnosis) of developing depression and/or anxiety.

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

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

Knowledge of Dietitians on Gut Microbiota in Health-An Online Survey of the European Federation of the Associations of Dietitians (EFAD)

Explorations of current knowledge of dietitians about gut-health interconnection and the role of diet in gut microbiota manipulation are rather scarce in the literature. In this online survey we assessed the perceived and current knowledge of dietitians across Europe about gut microbiota and systemic health, nutrition as a modulator of the gut ecosystem, and the role of probiotics and prebiotics. Pre-graduate dietetic students and other professionals were also invited to participate. A total of 179 full responses were recorded (dietitians, n = 155), mainly from Southern and Western regions. Most participants (>78.0%) reported an average to good level of perceived knowledge, with significant positive correlations between perceived and current knowledge in all sections and overall (p for all <0.05). Nevertheless, a rather low current knowledge scoring of participants about probiotics and prebiotics was observed. Features such as being a dietitian, having a higher educational level as dietitian and working in an academic/research setting were usually associated with higher current knowledge. Further analysis revealed that dietitians had a trend for higher scoring about probiotics and prebiotics compared to pre-graduate students or other professionals. Moreover, for dietitians, working in an academic or research setting was an independent factor for scoring in the highest quartile in all tested sections and overall (p for all <0.05). In conclusion, this online survey shed some light on the current knowledge of dietitians across Europe about gut microbiota parameters, including dietary modulation, highlighting in parallel possible knowledge determinants. Potential areas for future educational efforts in this rather unexplored field were indicated.

Placebo-resistant gut bacteria: Akkermansia muciniphila spp. and Familial Mediterranean fever disease

Introduction

Despite numerous investigations into the impact of drugs/probiotics on the gut microbiota composition in Familial Mediterranean Fever (FMF) patients, the question as to whether there exists a significant bacterial diversity(ies) independent of the placebo effect that can be reliably considered in clinical and nutritional trials remains unresolved.

Methods

This study represents the in augural analysis of the placebo's influence on the gut microbiota of both healthy individuals and FMF afflicted men, utilizing previously collected data from PhyloChip™ DNA microarray experiments. A total of 15 healthy and 15 FMF male volunteers, aged 18 to 50, participated in this partially randomized placebo trial, which is accessible through the GEO Series accession number GSE111835.

Results and Discussion

Key findings from current investigations include i. the anticipated divergence in gut bacteria resistance to placebo between healthy and FMF individuals, ii. the minor impact of placebo on gut bacterial diversities in healthy individuals, with Enterobacteriaceae diversities identified as placebo-resistant among "healthy" gut bacteria, and iii. the comprehensive influence of placebo on all bacterial phyla in the gut microbiome of FMF patients, extending to nearly all bacterial genera, except for the resilience of gut Akkermansia muciniphila spp. to placebo in FMF patients. This study underscores the susceptibility of Faecalibacterium, Blautia, and Clostridium genera to placebo. Consequently, this investigation holds significance for the proper design of placebo-controlled trials and establishes a foundation for further exploration of the gut-brain axis. Furthermore, it contributes valuable insights to discussions regarding proposals for probiotic therapies, particularly focusing on Faecalibacterium spp., Blautia spp., and Clostridium spp.

Pogostemon cablin essential oil affects anxiety- and depressive-like behaviors and the gut microbiota in chronic unpredictable mild stress model rats

The gut microbiota is thought to be an important factor that influences brain processes and behaviors through the gut-brain axis. Pogostemon cablin is used in traditional Chinese medicine (TCM) to treat gastrointestinal symptoms. Patchouli essential oil (PCO), the main active agent in P. cablin, is used in aromatherapy for stress relief. The aim of our study was to investigate the effects of orally administered PCO on anxiety- and depressive-like behaviors and the gut microbiota. We constructed a rat model of chronic unpredictable mild stress (CUMS) and explored the anxiolytic- and antidepressant-like effects of PCO using the open field test (OFT) and forced swim test (FST). Changes in the abundance of the gut microbiota, short-chain fatty acids (SCFAs), and other related molecules were assessed to determine the role of the gut microbiota. Our results showed that CUMS induced an anxiety-like phenotype in the OFT, which was reversed by PCO, and that PCO also significantly mitigated the depression-like behaviors caused by CUMS in the FST. Furthermore, we found that PCO increased the relative abundances of several probiotics, including Bacteroides and Blautia, and decreased the relative abundances of Ruminococcus_1 and Ruminococcus_2, which were increased by CUMS. Regarding SCFAs, the metabolites of the gut microbiota, PCO increased the concentration of propionic acid and decreased that of caproic acid. Finally, PCO restored the serotonin (5-hydroxytryptamine, 5-HT) level in the hippocampus, which had been decreased by CUMS. The results of this study suggested that PCO can improve stress-related anxiety- and depression-like behaviors and might exert its effects on the central nervous system through interactions with the gut microbiota.

Mood and microbes: a comprehensive review of intestinal microbiota's impact on depression

Depression is considered a multifaceted and intricate mental disorder of growing concern due to its significant impact on global health issues. The human gut microbiota, also known as the "second brain," has an important role in the CNS by regulating it through chemical, immunological, hormonal, and neurological processes. Various studies have found a significant bidirectional link between the brain and the gut, emphasizing the onset of depression therapies. The biological and molecular processes underlying depression and microbiota are required, as the bidirectional association may represent a novel study. However, profound insights into the stratification and diversity of the gut microbiota are still uncommon. This article investigates the emerging evidence of a bacterial relationship between the gut and the brain's neurological system and its potential pathogenicity and relevance. The interplay of microbiota, immune system, nervous system neurotransmitter synthesis, and neuroplasticity transitions is also widely studied. The consequences of stress, dietary fibers, probiotics, prebiotics, and antibiotics on the GB axis are being studied. Multiple studies revealed the processes underlying this axis and led to the development of effective microbiota-based drugs for both prevention and treatment. Therefore, the results support the hypothesis that gut microbiota influences depression and provide a promising area of research for an improved knowledge of the etiology of the disease and future therapies.

How the adaptation of the human microbiome to harsh space environment can determine the chances of success for a space mission to Mars and beyond

The ability of human cells to adapt to space radiation is essential for the well-being of astronauts during long-distance space expeditions, such as voyages to Mars or other deep space destinations. However, the adaptation of the microbiomes should not be overlooked. Microorganisms inside an astronaut's body, or inside the space station or other spacecraft, will also be exposed to radiation, which may induce resistance to antibiotics, UV, heat, desiccation, and other life-threatening factors. Therefore, it is essential to consider the potential effects of radiation not only on humans but also on their microbiomes to develop effective risk reduction strategies for space missions. Studying the human microbiome in space missions can have several potential benefits, including but not limited to a better understanding of the major effects space travel has on human health, developing new technologies for monitoring health and developing new radiation therapies and treatments. While radioadaptive response in astronauts' cells can lead to resistance against high levels of space radiation, radioadaptive response in their microbiome can lead to resistance against UV, heat, desiccation, antibiotics, and radiation. As astronauts and their microbiomes compete to adapt to the space environment. The microorganisms may emerge as the winners, leading to life-threatening situations due to lethal infections. Therefore, understanding the magnitude of the adaptation of microorganisms before launching a space mission is crucial to be able to develop effective strategies to mitigate the risks associated with radiation exposure. Ensuring the safety and well-being of astronauts during long-duration space missions and minimizing the risks linked with radiation exposure can be achieved by adopting this approach.

The bidirectional interaction between antidepressants and the gut microbiota: are there implications for treatment response?

This review synthesizes the evidence on associations between antidepressant use and gut microbiota composition and function, exploring the microbiota's possible role in modulating antidepressant treatment outcomes. Antidepressants exert an influence on measures of gut microbial diversity. The most consistently reported differences were in β-diversity between those exposed to antidepressants and those not exposed, with longitudinal studies supporting a potential causal association. Compositional alterations in antidepressant users include an increase in the Bacteroidetes phylum, Christensenellaceae family, and Bacteroides and Clostridium genera, while a decrease was found in the Firmicutes phylum, Ruminococcaceae family, and Ruminococcus genus. In addition, antidepressants attenuate gut microbial differences between depressed and healthy individuals, modulate microbial serotonin transport, and influence microbiota's metabolic functions. These include lyxose degradation, peptidoglycan maturation, membrane transport, and methylerythritol phosphate pathways, alongside gamma-aminobutyric acid metabolism. Importantly, baseline increased α-diversity and abundance of the Roseburia and Faecalibacterium genera, in the Firmicutes phylum, are associated with antidepressant response, emerging as promising biomarkers. This review highlights the potential for gut microbiota as a predictor of treatment response and emphasizes the need for further research to elucidate the mechanisms underlying antidepressant-microbiota interactions. More homogeneous studies and standardized techniques are required to confirm these initial findings.

Leger AJ, Galor A. Living with your biome: how the bacterial microbiome impacts ocular surface health and disease

Introduction

Microbiome research has grown exponentially but the ocular surface microbiome (OSM) remains an area in need of further study. This review aims to explore its complexity, disease-related microbial changes, and immune interactions, and highlights the potential for its manipulation as a therapeutic for ocular surface diseases.

Areas Covered

We introduce the OSM by location and describe what constitutes a normal OSM. Second, we highlight aspects of the ocular immune system and discuss potential immune microbiome interactions in health and disease. Finally, we highlight how microbiome manipulation may have therapeutic potential for ocular surface diseases.

Expert Opinion

The ocular surface microbiome varies across its different regions, with a core phyla identified, but with genus variability. A few studies have linked microbiome composition to diseases like dry eye but more research is needed, including examining microbiome interactions with the host. Studies have noted that manipulating the microbiome may impact disease presentation. As such, microbiome manipulation via diet, oral and topical pre and probiotics, and hygienic measures may provide new therapeutic algorithms in ocular surface diseases.

Are fecal samples an appropriate proxy for amphibian intestinal microbiota?

The intestinal microbiota, an invisible organ supporting a host's survival, has essential roles in metabolism, immunity, growth, and development. Since intestinal microbiota influences a host's biology, application of such data to wildlife conservation has gained interest. There are standard protocols for studying the human intestinal microbiota, but no equivalent for wildlife. A major challenge is sampling the intestinal microbiota in an effective, unbiased way. Fecal samples are a popular proxy for intestinal microbiota because collection is non-invasive and allows for longitudinal sampling. Yet it is unclear whether the fecal microbiota is representative of the intestinal microbiota. In wildlife studies, research on the sampling methodology is limited. In this study focusing on amphibians, we characterize and compare the microbiota (small intestine, large intestine, and feces) of two Hong Kong stream-dwelling frog species: Lesser Spiny Frog (Quasipaa exilispinosa) and Hong Kong Cascade Frog (Amolops hongkongensis). We found that the microbiota of both species are similar at the level of phylum and family, but diverge at the level of genus. When we assessed the performance of fecal microbiota in representing the intestinal microbiota in these two species, we found that (1) the microbiota of the small and large intestine differs significantly, (2) feces are not an appropriate proxy of either intestinal sections, and (3) a set of microbial taxa significantly differs between sample types. Our findings raise caution equating fecal and intestinal microbiota in stream-dwelling frogs. Sampling feces can avoid sacrifice of an animal, but researchers should avoid over-extrapolation and interpret results carefully.

Assessing the Effectiveness of ChatGPT in Delivering Mental Health Support: A Qualitative Study

Background

Artificial Intelligence (AI) applications are widely researched for their potential in effectively improving the healthcare operations and disease management. However, the research trend shows that these applications also have significant negative implications on the service delivery.

Purpose

To assess the use of ChatGPT for mental health support.

Methods

Due to the novelty and unfamiliarity of the ChatGPT technology, a quasi-experimental design was chosen for this study. Outpatients from a public hospital were included in the sample. A two-week experiment followed by semi-structured interviews was conducted in which participants used ChatGPT for mental health support. Semi-structured interviews were conducted with 24 individuals with mental health conditions.

Results

Eight positive factors (psychoeducation, emotional support, goal setting and motivation, referral and resource information, self-assessment and monitoring, cognitive behavioral therapy, crisis interventions, and psychotherapeutic exercises) and four negative factors (ethical and legal considerations, accuracy and reliability, limited assessment capabilities, and cultural and linguistic considerations) were associated with the use of ChatGPT for mental health support.

Conclusion

It is important to carefully consider the ethical, reliability, accuracy, and legal challenges and develop appropriate strategies to mitigate them in order to ensure safe and effective use of AI-based applications like ChatGPT in mental health support.

Translational bioinformatics and data science for biomarker discovery in mental health: an analytical review

Translational bioinformatics and data science play a crucial role in biomarker discovery as it enables translational research and helps to bridge the gap between the bench research and the bedside clinical applications. Thanks to newer and faster molecular profiling technologies and reducing costs, there are many opportunities for researchers to explore the molecular and physiological mechanisms of diseases. Biomarker discovery enables researchers to better characterize patients, enables early detection and intervention/prevention and predicts treatment responses. Due to increasing prevalence and rising treatment costs, mental health (MH) disorders have become an important venue for biomarker discovery with the goal of improved patient diagnostics, treatment and care. Exploration of underlying biological mechanisms is the key to the understanding of pathogenesis and pathophysiology of MH disorders. In an effort to better understand the underlying mechanisms of MH disorders, we reviewed the major accomplishments in the MH space from a bioinformatics and data science perspective, summarized existing knowledge derived from molecular and cellular data and described challenges and areas of opportunities in this space.

Microbiota Implications in Endocrine-Related Diseases: From Development to Novel Therapeutic Approaches

This comprehensive review article delves into the critical role of the human microbiota in the development and management of endocrine-related diseases. We explore the complex interactions between the microbiota and the endocrine system, emphasizing the implications of microbiota dysbiosis for the onset and progression of various endocrine disorders. The review aims to synthesize current knowledge, highlighting recent advancements and the potential of novel therapeutic approaches targeting microbiota-endocrine interactions. Key topics include the impact of microbiota on hormone regulation, its role in endocrine pathologies, and the promising avenues of microbiota modulation through diet, probiotics, prebiotics, and fecal microbiota transplantation. We underscore the importance of this research in advancing personalized medicine, offering insights for more tailored and effective treatments for endocrine-related diseases.

Long-Term Implicit Epigenetic Stress Information in the Enteric Nervous System and its Contribution to Developing and Perpetuating IBS

Psychiatric and mood disorders may play an important role in the development and persistence of irritable bowel syndrome (IBS). Previously, we hypothesized that stress-induced implicit memories may persist throughout life via epigenetic processes in the enteric nervous system (ENS), independent of the central nervous system (CNS). These epigenetic memories in the ENS may contribute to developing and perpetuating IBS. Here, we further elaborate on our earlier hypothesis. That is, during pregnancy, maternal prenatal stresses perturb the HPA axis and increase circulating cortisol levels, which can affect the maternal gut microbiota. Maternal cortisol can cross the placental barrier and increase cortisol-circulating levels in the fetus. This leads to dysregulation of the HPA axis, affecting the gut microbiota, microbial metabolites, and intestinal permeability in the fetus. Microbial metabolites, such as short-chain fatty acids (which also regulate the development of fetal ENS), can modulate a range of diseases by inducing epigenetic changes. These mentioned processes suggest that stress-related, implicit, long-term epigenetic memories may be programmed into the fetal ENS during pregnancy. Subsequently, this implicit epigenetic stress information from the fetal ENS could be conveyed to the CNS through the bidirectional microbiota-gut-brain axis (MGBA), leading to perturbed functional connectivity among various brain networks and the dysregulation of affective and pain processes.