Effects of Psychological, Environmental and Physical Stressors on the Gut Microbiota

Therapeutic strategies to modulate gut microbial health: Approaches for sarcopenia management

Sarcopenia is a progressive and generalized loss of skeletal muscle and functions associated with ageing with currently no definitive treatment. Alterations in gut microbial composition have emerged as a significant contributor to the pathophysiology of multiple diseases. Recently, its association with muscle health has pointed to its potential role in mediating sarcopenia. The current review focuses on the association of gut microbiota and mediators of muscle health, connecting the dots between the influence of gut microbiota and their metabolites on biomarkers of sarcopenia. It further delineates the mechanism by which the gut microbiota affects muscle health with progressing age, aiding the formulation of a multi-modal treatment plan involving nutritional supplements and pharmacological interventions along with lifestyle changes compiled in the review. Nutritional supplements containing proteins, vitamin D, omega-3 fatty acids, creatine, curcumin, kefir, and ursolic acid positively impact the gut microbiome. Dietary fibres foster a conducive environment for the growth of beneficial microbes such as Bifidobacterium, Faecalibacterium, Ruminococcus, and Lactobacillus. Probiotics and prebiotics act by protecting against reactive oxygen species (ROS) and inflammatory cytokines. They also increase the production of gut microbiota metabolites like short-chain fatty acids (SCFAs), which aid in improving muscle health. Foods rich in polyphenols are anti-inflammatory and have an antioxidant effect, contributing to a healthier gut. Pharmacological interventions like faecal microbiota transplantation (FMT), non-steroidal anti-inflammatory drugs (NSAIDs), ghrelin mimetics, angiotensin-converting enzyme inhibitors (ACEIs), and butyrate precursors lead to the production of anti-inflammatory fatty acids and regulate appetite, gut motility, and microbial impact on gut health. Further research is warranted to deepen our understanding of the interaction between gut microbiota and muscle health for developing therapeutic strategies for ameliorating sarcopenic muscle loss.

Current advances in microbiome sciences within the US Department of Defense-part 1: microbiomes for human health and performance

Microbiomes involve complex microbial communities where the microorganisms interact with one another as well as their associated hosts or environmental niches. The characterisation of these communities and associations have largely been achieved through 'omics' technologies, such as metagenomics, metaproteomics and metametabolomics, and model systems. Recent research in host-associated microbiomes have been aimed at understanding the roles microbes may play in host fitness or conversely how host activities/conditions may perturb the microbial community, which can further affect host health. These studies have led to the investigation of detection, intervention or modulation methods, which may serve to provide benefits to the host and advance our understanding of microbiome associations. With the clear implications on human health and disease, the US Department of Defense (DoD) has made microbiome research a priority, with the founding of the Tri-Service Microbiome Consortium (TSMC) to enhance collaboration, coordination and communication of microbiome research among DoD organisations and partners in academia and industry. DoD microbiome research focuses mainly on the following themes: (1) Human health and performance; (2) Environmental microbiomes; and (3) Enabling technologies. This review provides an update of current DoD microbiome research efforts centred on human health and performance and highlights innovative research being done in academia and industry that can be leveraged by the DoD. These topics were also communicated and further discussed during the fifth Annual TSMC Symposium. This paper forms part of the special issue of BMJ Military Health dedicated to Personalised Digital Technology for Mental Health in the Armed Forces.

The impact of test anxiety on oral microbiota among medical students-A pilot study

Test anxiety (TA) is a common emotion among students during examinations. Test-induced stress can remarkably impact students' emotions and limit their performance. Mental stress is a crucial factor that could significantly alter gut microbial composition, but rare reports focus on the correlation between TA and oral microbial composition. This study aims to investigate the impact of TA on students' oral microbiota composition. This study targeted medical students who usually face heavier workloads than average undergraduates. 28 females and 19 males aged 18-30 were enrolled in this study. Questionnaires and saliva samples were collected from the participants before, during, and after the end-term examination. The level of anxiety was classified as normal, mild, moderate, and severe based on the questionnaire scores. In addition, 16S amplicon sequencing was used to analyse the composition of oral microbes. More than half of the students faced different levels of TA before and after the examination. Over three-quarters of students showed anxiety during the examination, and a quarter suffered severe TA. The 16S sequencing data showed that TA significantly altered the oral microbial composition between students with and without TA in all three survey periods. Moreover, during the examination, the genera Rothia and Streptococcus, the oral-beneficial bacteria, markedly decreased in students with TA. On the other hand, the potential pathogenic genera, such as Prevotella, Fusobacterium, and Haemophilus, significantly increased in the students with TA. And the TA effect on oral microbes displayed a gender difference among students. A high ratio of TA existed in the students during their examination period, and TA could significantly alter the oral microbial composition, decrease beneficial microbes, and promote potential pathogenic oral microbes.

From gut to brain: unveiling probiotic effects through a neuroimaging perspective-A systematic review of randomized controlled trials

The gut-brain axis, a bidirectional communication network between the gastrointestinal system and the brain, significantly influences mental health and behavior. Probiotics, live microorganisms conferring health benefits, have garnered attention for their potential to modulate this axis. However, their effects on brain function through gut microbiota modulation remain controversial. This systematic review examines the effects of probiotics on brain activity and functioning, focusing on randomized controlled trials using both resting-state and task-based functional magnetic resonance imaging (fMRI) methodologies. Studies investigating probiotic effects on brain activity in healthy individuals and clinical populations (i.e., major depressive disorder and irritable bowel syndrome) were identified. In healthy individuals, task-based fMRI studies indicated that probiotics modulate brain activity related to emotional regulation and cognitive processing, particularly in high-order areas such as the amygdala, precuneus, and orbitofrontal cortex. Resting-state fMRI studies revealed changes in connectivity patterns, such as increased activation in the Salience Network and reduced activity in the Default Mode Network. In clinical populations, task-based fMRI studies showed that probiotics could normalize brain function in patients with major depressive disorder and irritable bowel syndrome. Resting-state fMRI studies further suggested improved connectivity in mood-regulating networks, specifically in the subcallosal cortex, amygdala and hippocampus. Despite promising findings, methodological variability and limited sample sizes emphasize the need for rigorous, longitudinal research to clarify the beneficial effects of probiotics on the gut-brain axis and mental health.

Intestinal biofilms: pathophysiological relevance, host defense, and therapeutic opportunities

SUMMARYThe human intestinal tract harbors a profound variety of microorganisms that live in symbiosis with the host and each other. It is a complex and highly dynamic environment whose homeostasis directly relates to human health. Dysbiosis of the gut microbiota and polymicrobial biofilms have been associated with gastrointestinal diseases, including irritable bowel syndrome, inflammatory bowel diseases, and colorectal cancers. This review covers the molecular composition and organization of intestinal biofilms, mechanistic aspects of biofilm signaling networks for bacterial communication and behavior, and synergistic effects in polymicrobial biofilms. It further describes the clinical relevance and diseases associated with gut biofilms, the role of biofilms in antimicrobial resistance, and the intestinal host defense system and therapeutic strategies counteracting biofilms. Taken together, this review summarizes the latest knowledge and research on intestinal biofilms and their role in gut disorders and provides directions toward the development of biofilm-specific treatments.

The Latest Data Concerning the Etiology and Pathogenesis of Irritable Bowel Syndrome

Globally, irritable bowel syndrome (IBS) is present in approximately 10% of the population. While this condition does not pose a risk of complications, it has a substantial impact on the patient's quality of life. Moreover, this disease has a significant financial impact on healthcare systems. This includes the direct costs associated with the diagnosis and treatment of these patients, as well as the indirect costs that arise from work absenteeism and reduced productivity. In light of these data, recent research has focused on elucidating the pathophysiological basis of this condition in order to improve the quality of life for affected individuals. Despite extensive research to date, we still do not fully understand the precise mechanisms underlying IBS. Numerous studies have demonstrated the involvement of the gut-brain axis, visceral hypersensitivity, gastrointestinal dysmotility, gut microbiota dysbiosis, food allergies and intolerances, low-grade mucosal inflammation, genetic factors, and psychosocial factors. The acquisition of new data is crucial for the advancement of optimal therapeutic approaches aimed at enhancing the general health of these patients while simultaneously reducing the financial burden associated with this ailment.

Why are we doing this Staff? Justification and implications of aerobic fitness testing in the military

BACKGROUND

Physical fitness is a key tenet of military organisations worldwide. Specifically, many consider aerobic fitness (AF) an essential physical attribute for ensuring optimal military performance and readiness. However, the intricate relationship between AF and various facets of military job performance necessitates comprehensive review to ascertain the appropriateness and effectiveness of its assessment.

OBJECTIVE

This narrative review aims to describe the relationship between AF and factors influencing individual military performance and readiness, and explores the implications of the enforcement of in-service, generic AF test standards in military populations.

METHODS

Databases (PubMed and Google Scholar) were searched for all relevant published peer-reviewed literature as at August 2023.

RESULTS

Inconsistent associations were found between AF and outcomes influencing individual military performance (physical capabilities, cognitive capabilities, presenteeism and productivity, resilience, and technical/tactical capabilities) and readiness (mental health and wellbeing and physical health). Consequently, the level of AF needed for acceptable or optimal military performance remains uncertain.

CONCLUSIONS

AF is a cornerstone of health and performance, yet linking generic AF test standards to job performance is complex, with multiple factors interacting to influence outcomes. From existing literatures, there does not appear to be a specific level of AF at, and/or above, which acceptable military performance is achieved. As such, the enforcement of and emphasis on in-service, pass/fail, generic AF test standards in military populations is questionable and requires thoughtful re-evaluation. Role/task-specific AF should be assessed through evidence-based PES and the use of generic AF tests limited to the monitoring and benchmarking of health-related fitness.

Contribution of the seminal microbiome to paternal programming

The field of Developmental Origins of Health and Disease has primarily focused on maternal programming of offspring health. However, emerging evidence suggests that paternal factors, including the seminal microbiome, could potentially play important roles in shaping the developmental trajectory and long-term offspring health outcomes. Historically, the microbes present in the semen were regarded as inherently pathogenic agents. However, this dogma has recently been challenged by the discovery of a diverse commensal microbial community within the semen of healthy males. In addition, recent studies suggest that the transmission of semen-associated microbes into the female reproductive tract during mating has potentials to not only influence female fertility and embryo development but could also contribute to paternal programming in the offspring. In this review, we summarize the current knowledge on the seminal microbiota in both humans and animals followed by discussing their potential involvement in paternal programming of offspring health. We also propose and discuss potential mechanisms through which paternal influences are transmitted to offspring via the seminal microbiome. Overall, this review provides insights into the seminal microbiome-based paternal programing, which will expand our understanding of the potential paternal programming mechanisms which are currently focused primarily on the epigenetic modifications, oxidative stresses, and cytokines.

Postbiotics as Potential Detoxification Tools for Mitigation of Pesticides

Pesticides possess a pivotal role in the realm of agriculture and food manufacturing, as they effectively manage the proliferation of weeds, insects, plant pathogens, and microbial contaminations. They are valuable in some ways, but if misused, they can cause health issues like cancer, reproductive toxicity, neurological illnesses, and endocrine system disturbances. In this regard, practical methods for reducing pesticide residue in food should be used. For reducing pesticide residue in food processing, some strategies have been suggested. Recent research has been done on detoxification processes, including microorganisms like probiotics and their metabolites. The term "postbiotics" describes soluble substances, such as peptides, enzymes, teichoic acids, muropeptides generated from peptidoglycans, polysaccharides, proteins, and organic acids that are secreted by living bacteria or released after bacterial lysis. Due to their distinct chemical makeup, safe dosage guidelines, lengthy shelf lives, and presence of various signaling molecules that may have antioxidant, anti-inflammatory, anti-obesogenic, immunomodulatory, anti-hypertensive, and immunomodulatory effects, these postbiotics have attracted interest. They also can detoxify heavy metals, mycotoxins, and pesticides. Hydrolytic enzymes have been proposed as a potential mechanism for pesticide degradation. Postbiotics can also reduce reactive oxygen species production, enhance gastrointestinal barrier function, reduce inflammation, and modulate host xenobiotic metabolism. This review highlights pesticide residues in food products, definitions and safety aspect of postbiotics, as well as their biological role in detoxification of pesticides and the protective role of these compounds against the adverse effects of pesticides.

Exploring microbiota-gut-brain axis biomarkers linked to autism spectrum disorder in prenatally chlorpyrifos-exposed Fmr1 knock-out and wild-type male rats

Fmr1 (fragile X messenger ribonucleoprotein 1)-knockout (KO) rats, modeling the human Fragile X Syndrome (FXS), are of particular interest for exploring the ASD-like phenotype in preclinical studies. Gestational exposure to chlorpyrifos (CPF) has been associated with ASD diagnosis in humans and ASD-like behaviors in rodents and linked to the microbiota-gut-brain axis. In this study, we have used both Fmr1-KO and wild-type male rats (F2 generation) at postnatal days (PND) 7 and 40 obtained after F1 pregnant females were randomly exposed to 1 mg/kg/mL/day of CPF or vehicle. A nuclear magnetic resonance (NMR) metabolomics approach together with gene expression profiles of these F2 generation rats were employed to analyze different brain regions (such as prefrontal cortex, hippocampus, and cerebellum), whole large intestine (at PND7) and gut content (PND40). The statistical comparison of each matrix spectral profile unveiled tissue-specific metabolic fingerprints. Significant variations in some biomarker levels were detected among brain tissues of different genotypes, including taurine, myo-inositol, and 3-hydroxybutyric acid, and exposure to CPF induced distinct metabolic alterations, particularly in serine and myo-inositol. Additionally, this study provides a set of metabolites associated with gastrointestinal dysfunction in ASD, encompassing several amino acids, choline-derived compounds, bile acids, and sterol molecules. In terms of gene expression, genotype and gestational exposure to CPF had only minimal effects on decarboxylase 2 (gad2) and cholinergic receptor muscarinic 2 (chrm2) genes.

The Causal Effects between Mood Swings and Gastrointestinal Diseases: A Mendelian Randomization Study

Background

Numerous studies have examined the links between mental disorders such as depression and bipolar disorder, and gastrointestinal (GI) diseases. However, few studies have investigated the link between mood swings and GI diseases. Given the impact of mood swings on various conditions and the growing comprehension of the gut-brain axis, this study aims to explore their causal relationship using Mendelian randomization (MR) methods.

Methods

Single-nucleotide polymorphisms (SNPs) associated with mood swings were obtained from a recent study. SNPs associated with GI diseases were identified from the FinnGen project. We conducted two-sample bidirectional MR analyses using three methods, primarily the inverse variance weighting (IVW) method. Furthermore, we performed sensitivity analyses and false discovery rate (FDR) analysis to validate the accuracy and robustness of the results.

Results

Bidirectional MR analysis revealed significant causal effects between mood swings and GI diseases according to the IVW method (odds ratio (OR): 1.213; 95% confidence interval (CI): 1.118-1.316; P = 3.490e-6; P FDR = 8.730e-5). Mood swings were linked to an increased risk for 11 of 24 diseases, including five upper GI diseases (gastroesophageal reflux disease (GERD), acute gastritis, gastroduodenal ulcer, duodenal ulcer, and functional dyspepsia), two lower GI diseases (diverticular disease of the intestine and irritable bowel syndrome (IBS)) and four hepatobiliary and pancreatic diseases (nonalcoholic fatty liver disease (NAFLD), chronic pancreatitis, acute pancreatitis, and pancreatic cancer). Inverse MR analysis showed no causal relationship between 24 GI diseases and mood swings.

Conclusions

This comprehensive MR analysis suggests that genetically predicted mood swings may be a risk factor in the development of GI diseases. Interventions for mood swings may help to treat GI diseases.

Effects of the medicinal plant, Tamarindus indica, as a potential supplement, on growth, nutrient digestibility, body composition and hematological indices of Cyprinus carpio fingerlings

Tamarindus indica, a beneficial herb, has many health benefits but there is limited research on its use in fish nutrition industry. The current study investigated the effects of incorporating extracts of T. indica into the canola meal-based diets of Cyprinus carpio (common carp); following which, the growth, digestibility, carcass and hematological markers were assessed. A total of six diets were formulated with varying concentrations of T. indica extracts (TIE) viz, 0 %, 0.5 %, 1 %, 1.5 %, 2 % and 2.5 %. The fish (N = 270, 15 fish/tank with triplicates) in each tank were fed experimental diets for 70 days. The study demonstrated that TIE supplementation significantly improved the growth of common carp when compared to 0 % TIE level (control). The best results were observed at 1 % TIE level for the specific growth rate (1.68 ± 0.03 %), weight gain (15.00 ± 0.57 g), and feed conversion ratio (1.36 ± 0.05). Conversely, the 2.5 % TIE level gave the least improvement in terms of growth performance. Specifically for nutrient digestibility, the maximum values of crude protein (CP, 67.60 ± 0.83 %), crude fat (CF, 67.49 ± 0.45 %) and gross energy (GE, 70.90 ± 0.56 %) were recorded at 1 % TIE level. In addition, the best results of body composition (protein: 63.92 ± 0.06 %, ash: 18.60 ± 0.03 %, fat: 7.12 ± 0.02 % and moisture: 10.36 ± 0.04 %) and hematological indices, were measured in carps fed with 1 % supplementation level. In conclusion, the overall health of C. carpio fingerlings was improved with TIE supplementation in the diet containing 1 % TIE.

Road traffic noise exposure and its impact on health: evidence from animal and human studies-chronic stress, inflammation, and oxidative stress as key components of the complex downstream pathway underlying noise-induced non-auditory health effects

In heavily urbanized world saturated with environmental pollutants, road traffic noise stands out as a significant factor contributing to widespread public health issues. It contributes in the development of a diverse range of non-communicable diseases, such as cardiovascular diseases, metabolic dysregulation, cognitive impairment, and neurodegenerative disorders. Although the exact mechanisms behind these non-auditory health effects remain unclear, the noise reaction model centres on the stress response to noise. When exposed to noise, the body activates the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system, leading to the secretion of stress hormones like catecholamines and cortisol. Prolonged exposure to noise-induced stress results in chronic inflammation and oxidative stress. This review underscores the role of inflammation and oxidative stress in the progression of noise-induced vascular dysfunction, disruption of the circadian rhythm, accelerated aging, neuroinflammation, and changes in microbiome. Additionally, our focus is on understanding the interconnected nature of these health outcomes: These interconnected factors create a cascade effect, contributing to the accumulation of multiple risk factors that ultimately lead to severe adverse health effects.

Microbiome and Metabolite Analysis Insight into the Potential of Shrimp Head Hydrolysate to Alleviate Depression-like Behaviour in Growth-Period Mice Exposed to Chronic Stress

Chronic stress (CS) endangers the physical and mental health of adolescents. Therefore, alleviating and preventing such negative health impacts are a top priority. This study explores the effect of feeding shrimp head hydrolysate (SHH) on gut microbiota, short-chain fatty acids (SCFAs), and neurotransmitters in growing C57BL/6 mice subjected to chronic unpredictable mild stress. Mice in the model group and three SHH groups were exposed to CS for 44 days, distilled water and SHH doses of 0.18, 0.45, 0.90 g/kg·BW were given respectively by gavage daily for 30 days from the 15th day. The results showed that SHH can significantly reverse depression-like behaviour, amino acids degradation, α diversity and β diversity, proportion of Firmicutes and Bacteroidota, abundance of genera such as Muribaculaceae, Bacteroides, Prevotellaceae_UCG-001, Parabacteroides and Alistipes, concentration of five short-chain fatty acids (SCFAs), 5-HT and glutamate induced by CS. Muribaculaceae and butyric acid may be a controlled target. This study highlights the potential and broad application of SHH as an active ingredient in food to combat chronic stress damage.

Rejuvenating fecal microbiota transplant enhances peripheral nerve repair in aged mice by modulating endoneurial inflammation

Peripheral nerve injury (PNI) resulting from trauma or neuropathies can cause significant disability, and its prognosis deteriorates with age. Emerging evidence suggests that gut dysbiosis and reduced fecal short-chain fatty acids (SCFAs) contribute to an age-related systemic hyperinflammation (inflammaging), which hinders nerve recovery after injury. This study thus aimed to evaluate the pro-regenerative effects of a rejuvenating fecal microbiota transplant (FMT) in a preclinical PNI model using aged mice. Aged C57BL/6 mice underwent bilateral crush injuries to their sciatic nerves. Subsequently, they either received FMT from young donors at three and four days after the injury or retained their aged gut microbiota. We analyzed gut microbiome composition and SCFA concentrations in fecal samples. The integrity of the ileac mucosal barrier was assessed by immunofluorescence staining of Claudin-1. Flow cytometry was utilized to examine immune cells and cytokine production in the ileum, spleen, and sciatic nerve. Various assessments, including behavioural tests, electrophysiological studies, and morphometrical analyses, were conducted to evaluate peripheral nerve function and repair following injury. Rejuvenating FMT reversed age-related gut dysbiosis by increasing Actinobacteria, especially Bifidobacteriales genera. This intervention also led to an elevation of gut SCFA levels and mitigated age-related ileac mucosal leakiness in aged recipients. Additionally, it augmented the number of T-helper 2 (Th2) and regulatory T (Treg) cells in the ileum and spleen, with the majority being positive for anti-inflammatory interleukin-10 (IL-10). In sciatic nerves, rejuvenating FMT resulted in increased M2 macrophage counts and a higher IL-10 production by IL-10+TNF-α- M2 macrophage subsets. Ultimately, restoring a youthful gut microbiome in aged mice led to improved nerve repair and enhanced functional recovery after PNI. Considering that FMT is already a clinically available technique, exploring novel translational strategies targeting the gut microbiome to enhance nerve repair in the elderly seems promising and warrants further evaluation.

Superparamagnetic iron oxide nanoparticle regulates microbiota-gut-inner ear axis for hearing protection

Noise-induced hearing loss (NIHL) is a highly prevalent form of sensorineural hearing damage that has significant negative effects on individuals of all ages and there are no effective drugs approved by the US Food and Drug Administration. In this study, we unveil the potential of superparamagnetic iron oxide nanoparticle assembly (SPIOCA) to reshape the dysbiosis of gut microbiota for treating NIHL. This modulation inhibits intestinal inflammation and oxidative stress responses, protecting the integrity of the intestinal barrier. Consequently, it reduces the transportation of pathogens and inflammatory factors from the bloodstream to the cochlea. Additionally, gut microbiota-modulated SPIOCA-induced metabolic reprogramming in the gut-inner ear axis mainly depends on the regulation of the sphingolipid metabolic pathway, which further contributes to the restoration of hearing function. Our study confirms the role of the microbiota-gut-inner ear axis in NIHL and provides a novel alternative for the treatment of NIHL and other microbiota dysbiosis-related diseases.

Functional and mechanistic studies of a phytogenic formulation, Shrimp Best, in growth performance and vibriosis in whiteleg shrimp

Climate change and disease threaten shrimp farming. Here, we studied the beneficial properties of a phytogenic formulation, Shrimp Best (SB), in whiteleg shrimp. Functional studies showed that SB dose-dependently increased shrimp body weight and decreased feed conversion ratio. We found that SB protected against Vibrio parahaemolyticus as evidenced by survival rate, bacterial load, and hepatopancreatic pathology in shrimp. Finally, we explored the likely mechanism by which SB affects growth performance and vibriosis in shrimp. The 16S rRNA sequencing data showed that SB increased 6 probiotic genera and decreased 6 genera of pathogenic bacteria in shrimp. Among these, SB increased the proportion of Lactobacillus johnsonii and decreased that of V. parahaemolyticus in shrimp guts. To dissect the relationship among SB, Lactobacillus and Vibrio, we investigated the in vitro regulation of Lactobacillus and Vibrio by SB. SB at ≥ 0.25 μg/mL promoted L. johnsonii growth. Additionally, L. johnsonii and its supernatant could inhibit V. parahaemolyticus. Furthermore, SB could up-regulate five anti-Vibrio metabolites of L. johnsonii, which caused bacterial membrane destruction. In parallel, we identified 3 fatty acids as active compounds from SB. Overall, this work demonstrated that SB improved growth performance and vibriosis protection in shrimp via the regulation of gut microbiota.

Oral Exposure to Benzalkonium Chlorides in Male and Female Mice Reveals Sex-Dependent Alteration of the Gut Microbiome and Bile Acid Profile

Benzalkonium chlorides (BACs) are commonly used disinfectants in a variety of consumer and food-processing settings, and the COVID-19 pandemic has led to increased usage of BACs. The prevalence of BACs raises the concern that BAC exposure could disrupt the gastrointestinal microbiota, thus interfering with the beneficial functions of the microbes. We hypothesize that BAC exposure can alter the gut microbiome diversity and composition, which will disrupt bile acid homeostasis along the gut-liver axis. In this study, male and female mice were exposed orally to d 7 -C12- and d 7 -C16-BACs at 120 µg/g/day for one week. UPLC-MS/MS analysis of liver, blood, and fecal samples of BAC-treated mice demonstrated the absorption and metabolism of BACs. Both parent BACs and their metabolites were detected in all exposed samples. Additionally, 16S rRNA sequencing was carried out on the bacterial DNA isolated from the cecum intestinal content. For female mice, and to a lesser extent in males, we found that treatment with either d 7 -C12- or d 7 -C16-BAC led to decreased alpha diversity and differential composition of gut bacteria with notably decreased actinobacteria phylum. Lastly, through a targeted bile acid quantitation analysis, we observed decreases in secondary bile acids in BAC-treated mice, which was more pronounced in the female mice. This finding is supported by decreases in bacteria known to metabolize primary bile acids into secondary bile acids, such as the families of Ruminococcaceae and Lachnospiraceae. Together, these data signify the potential impact of BACs on human health through disturbance of the gut microbiome and gut-liver interactions.

Diet quality and anxiety: a critical overview with focus on the gut microbiome

Anxiety disorders disproportionally affect females and are frequently comorbid with eating disorders. With the emerging field of nutritional psychiatry, focus has been put on the impact of diet quality in anxiety pathophysiology and gut microbiome underlying mechanisms. While the relationship between diet and anxiety is bidirectional, improving dietary habits could better facilitate the actions of pharmacological and psychological therapies, or prevent their use. A better understanding of how gut bacteria mediate and moderate such relationship could further contribute to develop personalized programs and inform probiotics and prebiotics manufacturing. To date, studies that look simultaneously at diet, the gut microbiome, and anxiety are missing as only pairwise relationships among them have been investigated. Therefore, this study aims at summarizing and integrating the existing knowledge on the dietary effects on anxiety with focus on gut microbiome. Findings on the effects of diet on anxiety are critically summarized and reinterpreted in relation to findings on (i) the effects of diet on the gut microbiome composition, and (ii) the associations between the abundance of certain gut bacteria and anxiety. This novel interpretation suggests a theoretical model where the relationship between diet and anxiety is mediated and/or modulated by the gut microbiome through multiple mechanisms. In parallel, this study critically evaluates methodologies employed in the nutritional field to investigate the effects of diet on anxiety highlighting a lack of systematic operationalization and assessment strategies. Therefore, it ultimately proposes a novel evidence-based approach that can enhance studies validity, reliability, systematicity, and translation to clinical and community settings.

The central executive network moderates the relationship between posttraumatic stress symptom severity and gastrointestinal related issues

Although most adults experience at least one traumatic event in their lifetime, a smaller proportion will go on to be clinically diagnosed with post-traumatic stress disorder (PTSD). Persons diagnosed with PTSD have a greater likelihood of developing gastrointestinal (GI) disorders. However, the extent to which subclinical levels of post-traumatic stress (PTS) correspond with the incidence of GI issues in a normative sample is unclear. Resting state fMRI, medical history, psychological survey, and anthropometric data were acquired from the Enhanced Nathan Kline Institute-Rockland Sample (n = 378; age range 18-85.6 years). The primary aim of this study was to test the main effect of subclinical PTS symptom severity on the number of endorsed GI issues. The secondary aim was to test the moderating effect of high versus low resting state functional connectivity (rsFC) of the central executive network (CEN) on the relationship between PTS symptom severity and GI issues. Trauma Symptom Checklist-40 (TSC-40) scores were positively associated with the number of endorsed GI issues (b = -0.038, SE = .009, p < .001). The interaction between TSC-40 scores and rsFC within the CEN was significant on GI issues after controlling for sociodemographic and cardiometabolic variables (b = -0.031, SE = .016, p < .05), such that above average rsFC within the CEN buffered the effect of TSC-40 scores on GI issues. Our findings of higher rsFC within the CEN moderating the magnitude of coincidence in PTS and GI symptom severity may reflect the mitigating role of executive control processes in the putative stress signaling mechanisms that contribute to gut dysbiosis.

High-altitude-induced alterations in intestinal microbiota

In high-altitude environments characterized by low pressure and oxygen levels, the intestinal microbiota undergoes significant alterations. Whether individuals are subjected to prolonged exposure or acute altitude changes, these conditions lead to shifts in both the diversity and abundance of intestinal microbiota and changes in their composition. While these alterations represent adaptations to high-altitude conditions, they may also pose health risks through certain mechanisms. Changes in the intestinal microbiota induced by high altitudes can compromise the integrity of the intestinal mucosal barrier, resulting in gastrointestinal dysfunction and an increased susceptibility to acute mountain sickness (AMS). Moreover, alterations in the intestinal microbiota have been implicated in the induction or exacerbation of chronic heart failure. Targeted modulation of the intestinal microbiota holds promise in mitigating high-altitude-related cardiac damage. Dietary interventions, such as adopting a high-carbohydrate, high-fiber, low-protein, and low-fat diet, can help regulate the effects of intestinal microbiota and their metabolic byproducts on intestinal health. Additionally, supplementation with probiotics, either through dietary sources or medications, offers a means of modulating the composition of the intestinal microbiota. These interventions may offer beneficial effects in preventing and alleviating AMS following acute exposure to high altitudes.

An altered gut microbiome in pre-eclampsia: cause or consequence

Hypertensive disorders of pregnancy, including pre-eclampsia, are a leading cause of serious and debilitating complications that affect both the mother and the fetus. Despite the occurrence and the health implications of these disorders there is still relatively limited evidence on the molecular underpinnings of the pathophysiology. An area that has come to the fore with regard to its influence on health and disease is the microbiome. While there are several microbiome niches on and within the body, the distal end of the gut harbors the largest of these impacting on many different systems of the body including the central nervous system, the immune system, and the reproductive system. While the role of the microbiome in hypertensive disorders, including pre-eclampsia, has not been fully elucidated some studies have indicated that several of the symptoms of these disorders are linked to an altered gut microbiome. In this review, we examine both pre-eclampsia and microbiome literature to summarize the current knowledge on whether the microbiome drives the symptoms of pre-eclampsia or if the aberrant microbiome is a consequence of this condition. Despite the paucity of studies, obvious gut microbiome changes have been noted in women with pre-eclampsia and the individual symptoms associated with the condition. Yet further research is required to fully elucidate the role of the microbiome and the significance it plays in the development of the symptoms. Regardless of this, the literature highlights the potential for a microbiome targeted intervention such as dietary changes or prebiotic and probiotics to reduce the impact of some aspects of these disorders.

Beyond probiotics, uses of their next-generation for poultry and humans: A review

The production of healthy food is one of the basic requirements and challenges. Research efforts have been introduced in the human's food industry to reduce the microbial resistance and use safe and healthy alternatives with a high durability. However, the conducted work about these issues in the field of livestock animal production have been started since 2015. Inappropriate and extensive use of antibiotics has resulted in the increase of antimicrobial resistance, presence of drug residues in tissues, and destruction of the gut microbiome. Therefore, discovering and developing antibiotic substitutes were urgent demands. Probiotic compounds containing living micro-organisms are important antibiotic alternative that have been beneficially and extensively used in humans, animals, and poultry. However, some probiotics show some obstacles during production and applications. Accordingly, this review article proposes a comprehensive description of the next-generation of probiotics including postbiotics, proteobiotics, psychobiotics, immunobiotics and paraprobiotics and their effects on poultry production and human's therapy. These compounds proved great efficiency in terms of restoring gut health, improving performance and general health conditions, modulating the immune response and reducing the pathogenic micro-organisms. However, more future research work should be carried out regarding this issue.

The Profound Influence of Gut Microbiome and Extracellular Vesicles on Animal Health and Disease

The animal gut microbiota, comprising a diverse array of microorganisms, plays a pivotal role in shaping host health and physiology. This review explores the intricate dynamics of the gut microbiome in animals, focusing on its composition, function, and impact on host-microbe interactions. The composition of the intestinal microbiota in animals is influenced by the host ecology, including factors such as temperature, pH, oxygen levels, and nutrient availability, as well as genetic makeup, diet, habitat, stressors, and husbandry practices. Dysbiosis can lead to various gastrointestinal and immune-related issues in animals, impacting overall health and productivity. Extracellular vesicles (EVs), particularly exosomes derived from gut microbiota, play a crucial role in intercellular communication, influencing host health by transporting bioactive molecules across barriers like the intestinal and brain barriers. Dysregulation of the gut-brain axis has implications for various disorders in animals, highlighting the potential role of microbiota-derived EVs in disease progression. Therapeutic approaches to modulate gut microbiota, such as probiotics, prebiotics, microbial transplants, and phage therapy, offer promising strategies for enhancing animal health and performance. Studies investigating the effects of phage therapy on gut microbiota composition have shown promising results, with potential implications for improving animal health and food safety in poultry production systems. Understanding the complex interactions between host ecology, gut microbiota, and EVs provides valuable insights into the mechanisms underlying host-microbe interactions and their impact on animal health and productivity. Further research in this field is essential for developing effective therapeutic interventions and management strategies to promote gut health and overall well-being in animals.

Gut microbiome resilience of green-lipped mussels, Perna canaliculus, to starvation

Host gut microbiomes play an important role in animal health and resilience to conditions, such as malnutrition and starvation. These host-microbiome relationships are poorly understood in the marine mussel Perna canaliculus, which experiences significant variations in food quantity and quality in coastal areas. Prolonged starvation may be a contributory factor towards incidences of mass mortalities in farmed mussel populations, resulting in highly variable production costs and unreliable market supplies. Here, we examine the gut microbiota of P. canaliculus in response to starvation and subsequent re-feeding using high-throughput amplicon sequencing of the 16S rRNA gene. Mussels showed no change in bacterial species richness when subjected to a 14-day starvation, followed by re-feeding/recovery. However, beta bacteria diversity revealed significant shifts (PERMANOVA p-value < 0.001) in community structure in the starvation group and no differences in the subsequent recovery group (compared to the control group) once they were re-fed, highlighting their recovery capability and resilience. Phylum-level community profiles revealed an elevation in dominance of Proteobacteria (ANCOM-BC p-value <0.001) and Bacteroidota (ANCOM-BC p-value = 0.04) and lower relative abundance of Cyanobacteria (ANCOM-BC p-value = 0.01) in the starvation group compared to control and recovery groups. The most abundant genus-level shifts revealed relative increases of the heterotroph Halioglobus (p-value < 0.05) and lowered abundances of the autotroph Synechococcus CC9902 in the starvation group. Furthermore, a SparCC correlation network identified co-occurrence of a cluster of genera with elevated relative abundance in the starved mussels that were positively correlated with Synechococcus CC9902. The findings from this work provide the first insights into the effect of starvation on the resilience capacity of Perna canaliculus gut microbiota, which is of central importance to understanding the effect of food variation and limitation in farmed mussels.

Effects of subchronic and mild social defeat stress on the intestinal microbiota and fecal bile acid composition in mice

The gut microbiota plays a crucial role in both the pathogenesis and alleviation of host depression by modulating the brain-gut axis. We have developed a murine model of human depression called the subchronic and mild social defeat stress (sCSDS) model, which impacts not only behavior but also the host gut microbiota and gut metabolites, including bile acids. In this study, we utilized liquid chromatography/mass spectrometry (LC/MS) to explore the effects of sCSDS on the mouse fecal bile acid profile. sCSDS mice exhibited significantly elevated levels of deoxycholic acid (DCA) and lithocholic acid (LCA) in fecal extracts, leading to a notable increase in total bile acids and 7α-dehydroxylated secondary bile acids. Consequently, a noteworthy negative correlation was identified between the abundances of DCA and LCA and the social interaction score, an indicator of susceptibility in stressed mice. Furthermore, analysis of the colonic microbiome unveiled a negative correlation between the abundance of CDCA and Turicibacter. Additionally, DCA and LCA exhibited positive correlations with Oscillospiraceae and Lachnospiraceae but negative correlations with the Eubacterium coprostanoligenes group. These findings suggest that sCSDS impacts the bidirectional interaction between the gut microbiota and bile acids and is associated with reduced social interaction, a behavioral indicator of susceptibility in stressed mice.

Gut microbiota profile in CDKL5 deficiency disorder patients

CDKL5 deficiency disorder (CDD) is a neurodevelopmental condition characterized by global developmental delay, early-onset seizures, intellectual disability, visual and motor impairments. Unlike Rett Syndrome (RTT), CDD lacks a clear regression period. Patients with CDD frequently encounter gastrointestinal (GI) disturbances and exhibit signs of subclinical immune dysregulation. However, the underlying causes of these conditions remain elusive. Emerging studies indicate a potential connection between neurological disorders and gut microbiota, an area completely unexplored in CDD. We conducted a pioneering study, analyzing fecal microbiota composition in individuals with CDD (n = 17) and their healthy relatives (n = 17). Notably, differences in intestinal bacterial diversity and composition were identified in CDD patients. In particular, at genus level, CDD microbial communities were characterized by an increase in the relative abundance of Clostridium_AQ, Eggerthella, Streptococcus, and Erysipelatoclostridium, and by a decrease in Eubacterium, Dorea, Odoribacter, Intestinomonas, and Gemmiger, pointing toward a dysbiotic profile. We further investigated microbiota changes based on the severity of GI issues, seizure frequency, sleep disorders, food intake type, impairment in neuro-behavioral features and ambulation capacity. Enrichment in Lachnoclostridium and Enterobacteriaceae was observed in the microbiota of patients with more severe GI symptoms, while Clostridiaceae, Peptostreptococcaceae, Coriobacteriaceae, Erysipelotrichaceae, Christensenellaceae, and Ruminococcaceae were enriched in patients experiencing daily epileptic seizures. Our findings suggest a potential connection between CDD, microbiota and symptom severity. This study marks the first exploration of the gut-microbiota-brain axis in subjects with CDD. It adds to the growing body of research emphasizing the role of the gut microbiota in neurodevelopmental disorders and opens doors to potential interventions that target intestinal microbes with the aim of improving the lives of patients with CDD.

Association of Blast Exposure in Military Breaching with Intestinal Permeability Blood Biomarkers Associated with Leaky Gut

Injuries and subclinical effects from exposure to blasts are of significant concern in military operational settings, including tactical training, and are associated with self-reported concussion-like symptomology and physiological changes such as increased intestinal permeability (IP), which was investigated in this study. Time-series gene expression and IP biomarker data were generated from "breachers" exposed to controlled, low-level explosive blast during training. Samples from 30 male participants at pre-, post-, and follow-up blast exposure the next day were assayed via RNA-seq and ELISA. A battery of symptom data was also collected at each of these time points that acutely showed elevated symptom reporting related to headache, concentration, dizziness, and taking longer to think, dissipating ~16 h following blast exposure. Evidence for bacterial translocation into circulation following blast exposure was detected by significant stepwise increase in microbial diversity (measured via alpha-diversity p = 0.049). Alterations in levels of IP protein biomarkers (i.e., Zonulin, LBP, Claudin-3, I-FABP) assessed in a subset of these participants (n = 23) further evidenced blast exposure associates with IP. The observed symptom profile was consistent with mild traumatic brain injury and was further associated with changes in bacterial translocation and intestinal permeability, suggesting that IP may be linked to a decrease in cognitive functioning. These preliminary findings show for the first time within real-world military operational settings that exposures to blast can contribute to IP.

Cold exposure, gut microbiota and health implications: A narrative review

Temperature has been recognized as an important environmental factor affecting the composition and function of gut microbiota (GM). Although research on high-temperature impacts has been well studied, knowledge about the effect of cold exposure on GM remains limited. This narrative review aims to synthesize the latest scientific findings on the impact of cold exposure on mammalian GM, and its potential health implications. Chronic cold exposure could disrupt the α-diversity and the composition of GM in both experimental animals and wild-living hosts. Meanwhile, cold exposure could impact gut microbial metabolites, such as short-chain fatty acids. We also discussed plausible biological pathways and mechanisms by which cold-induced changes may impact host health, including metabolic homeostasis, fitness and thermogenesis, through the microbiota-gut-brain axis. Intriguingly, alterations in GM may provide a tool for favorably modulating the host response to the cold temperature. Finally, current challenges and future perspectives are discussed, emphasizing the need for translational research in humans. GM could be manipulated by utilizing nutritional strategies, such as probiotics and prebiotics, to deal with cold-related health issues and enhance well-being in populations living or working in cold environments.

Strain specific differences in vitamin D3 response: impact on gut homeostasis

Vitamin D3 regulates a variety of biological processes irrespective of its well-known importance for calcium metabolism. Epidemiological and animal studies indicate a role in immune regulation, intestinal barrier function and microbiome diversity. Here, we analyzed the impact of different vitamin D3- containing diets on C57BL/6 and BALB/c mice, with a particular focus on gut homeostasis and also investigated effects on immune cells in vitro. Weak regulatory effects were detected on murine T cells. By trend, the active vitamin D3 metabolite 1,25-dihydroxyvitamin D3 suppressed IFN, GM-CSF and IL-10 cytokine secretion in T cells of C57BL/6 but not BALB/c mice, respectively. Using different vitamin D3-fortified diets, we found a tissue-specific enrichment of mainly CD11b+ myeloid cells but not T cells in both mouse strains e.g. in spleen and Peyer's Patches. Mucin Reg3γ and Batf expression, as well as important proteins for gut homeostasis, were significantly suppressed in the small intestine of C57BL76 but not BALB/c mice fed with a high-vitamin D3 containing diet. Differences between both mouse stains were not completely explained by differences in vitamin D3 receptor expression which was strongly expressed in epithelial cells of both strains. Finally, we analyzed gut microbiome and again an impact of vitamin D3 was detected in C57BL76 but not BALB/c. Our data suggest strain-specific differences in vitamin D3 responsiveness under steady state conditions which may have important implications when choosing a murine disease model to study vitamin D3 effects.

Local and Systemic Effects of Bioactive Food Ingredients: Is There a Role for Functional Foods to Prime the Gut for Resilience?

Scientific advancements in understanding the impact of bioactive components in foods on the gut microbiota and wider physiology create opportunities for designing targeted functional foods. The selection of bioactive ingredients with potential local or systemic effects holds promise for influencing overall well-being. An abundance of studies demonstrate that gut microbiota show compositional changes that correlate age and disease. However, navigating this field, especially for non-experts, remains challenging, given the abundance of bioactive ingredients with varying levels of scientific substantiation. This narrative review addresses the current knowledge on the potential impact of the gut microbiota on host health, emphasizing gut microbiota resilience. It explores evidence related to the extensive gut health benefits of popular dietary components and bioactive ingredients, such as phytochemicals, fermented greens, fibres, prebiotics, probiotics, and postbiotics. Importantly, this review distinguishes between the potential local and systemic effects of both popular and emerging ingredients. Additionally, it highlights how dietary hormesis promotes gut microbiota resilience, fostering better adaptation to stress-a hallmark of health. By integrating examples of bioactives, this review provides insights to guide the design of evidence-based functional foods aimed at priming the gut for resilience.

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.

A cross-sectional study observing the association of psychosocial stress and dietary intake with gut microbiota genera and alpha diversity among a young adult cohort of black and white women in Birmingham, Alabama

BACKGROUND

The relationships between psychosocial stress and diet with gut microbiota composition and diversity deserve ongoing investigation. The primary aim of this study was to examine the associations of psychosocial stress measures and dietary variables with gut microbiota genera abundance and alpha diversity among young adult, black and white females. The secondary aim was to explore mediators of psychosocial stress and gut microbiota diversity and abundance.

METHODS

Data on 60 females who self-identified as African American (AA; n = 29) or European American (EA; n = 31) aged 21-45 years were included. Cortisol was measured in hair and saliva, and 16S analysis of stool samples were conducted. Discrimination experiences (recent and lifetime), perceived stress, and depression were evaluated based on validated instruments. Spearman correlations were performed to evaluate the influence of psychosocial stressors, cortisol measures, and dietary variables on gut microbiota genus abundance and alpha diversity measured by amplicon sequence variant (ASV) count. Mediation analyses assessed the role of select dietary variables and cortisol measures on the associations between psychosocial stress, Alistipes and Blautia abundance, and ASV count.

RESULTS

AA females were found to have significantly lower ASV count and Blautia abundance. Results for the spearman correlations assessing the influence of psychosocial stress and dietary variables on gut microbiota abundance and ASV count were varied. Finally, diet nor cortisol was found to partially or fully mediate the associations between subjective stress measures, ASV count, and Alistipes and Blautia abundance.

CONCLUSION

In this cross-sectional study, AA females had lower alpha diversity and Blautia abundance compared to EA females. Some psychosocial stressors and dietary variables were found to be correlated with ASV count and few gut microbiota genera. Larger scale studies are needed to explore the relationships among psychosocial stress, diet and the gut microbiome.

Effect of three different insect larvae on growth performance and antioxidant activity of thigh, breast, and liver tissues of chickens reared under mild heat stress

This study investigated the potential of insect-based diets to mitigate heat stress impact on broiler chickens, focusing on growth performance and antioxidant stability. Four dietary groups were examined, including a control and three treated groups with Tenebrio molitor (TM), Hermetia illucens (HI), and Zophobas morio (ZM) larvae, respectively, at a 5% replacement ratio. Temperature and relative humidity of the poultry house were monitored. Under heat stress conditions, the HI-fed group consistently exhibited the highest body weight, demonstrating their remarkable growth-promoting potential. TM-fed broilers also displayed commendable growth compared to the control. Insect larvae inclusion in the diet improved feed intake during early growth stages, indicating their positive influence on nutrient utilization. Regarding antioxidant stability, malondialdehyde (MDA) levels in the liver, an oxidative stress and lipid peroxidation marker, were significantly lower in the TM-fed group, suggesting reduced oxidative stress. While the specific insect-based diet did not significantly affect MDA levels in thigh and breast tissues, variations in the total phenolic content (TPC) were observed across tissues, with HI larvae significantly increasing it in the breast. However, the total antioxidant capacity (TAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) levels did not differ significantly among dietary groups in the examined tissues. Results suggest that insect-based diets enhance broiler growth and potentially reduce oxidative stress, particularly in the liver. Dietary presence of bioactive compounds may contribute to these benefits. Further research is required to fully elucidate the mechanisms underlying these findings. Insect-based diets seem to offer promise as feed additives in addressing the multifaceted challenges of oxidative stress and enhancing broiler health and resilience under heat stress conditions.

Metabolic model predictions enable targeted microbiome manipulation through precision prebiotics

While numerous health-beneficial interactions between host and microbiota have been identified, there is still a lack of targeted approaches for modulating these interactions. Thus, we here identify precision prebiotics that specifically modulate the abundance of a microbiome member species of interest. In the first step, we show that defining precision prebiotics by compounds that are only taken up by the target species but no other species in a community is usually not possible due to overlapping metabolic niches. Subsequently, we use metabolic modeling to identify precision prebiotics for a two-member Caenorhabditis elegans microbiome community comprising the immune-protective target species Pseudomonas lurida MYb11 and the persistent colonizer Ochrobactrum vermis MYb71. We experimentally confirm four of the predicted precision prebiotics, L-serine, L-threonine, D-mannitol, and γ-aminobutyric acid, to specifically increase the abundance of MYb11. L-serine was further assessed in vivo, leading to an increase in MYb11 abundance also in the worm host. Overall, our findings demonstrate that metabolic modeling is an effective tool for the design of precision prebiotics as an important cornerstone for future microbiome-targeted therapies.IMPORTANCEWhile various mechanisms through which the microbiome influences disease processes in the host have been identified, there are still only few approaches that allow for targeted manipulation of microbiome composition as a first step toward microbiome-based therapies. Here, we propose the concept of precision prebiotics that allow to boost the abundance of already resident health-beneficial microbial species in a microbiome. We present a constraint-based modeling pipeline to predict precision prebiotics for a minimal microbial community in the worm Caenorhabditis elegans comprising the host-beneficial Pseudomonas lurida MYb11 and the persistent colonizer Ochrobactrum vermis MYb71 with the aim to boost the growth of MYb11. Experimentally testing four of the predicted precision prebiotics, we confirm that they are specifically able to increase the abundance of MYb11 in vitro and in vivo. These results demonstrate that constraint-based modeling could be an important tool for the development of targeted microbiome-based therapies against human diseases.

The human gut microbiome in critical illness: disruptions, consequences, and therapeutic frontiers

With approximately 39 trillion cells and over 20 million genes, the human gut microbiome plays an integral role in both health and disease. Modern living has brought a widespread use of processed food and beverages, antimicrobial and immunomodulatory drugs, and invasive procedures, all of which profoundly disrupt the delicate homeostasis between the host and its microbiome. Of particular interest is the human gut microbiome, which is progressively being recognized as an important contributing factor in many aspects of critical illness, from predisposition to recovery. Herein, we describe the current understanding of the adverse impacts of standard intensive care interventions on the human gut microbiome and delve into how these microbial alterations can influence patient outcomes. Additionally, we explore the potential association between the gut microbiome and post-intensive care syndrome, shedding light on a previously underappreciated avenue that may enhance patient recuperation following critical illness. There is an impending need for future epidemiological studies to encompass detailed phenotypic analyses of gut microbiome perturbations. Interventions aimed at restoring the gut microbiome represent a promising therapeutic frontier in the quest to prevent and treat critical illnesses.

Health position paper and redox perspectives - Disease burden by transportation noise

Transportation noise is a ubiquitous urban exposure. In 2018, the World Health Organization concluded that chronic exposure to road traffic noise is a risk factor for ischemic heart disease. In contrast, they concluded that the quality of evidence for a link to other diseases was very low to moderate. Since then, several studies on the impact of noise on various diseases have been published. Also, studies investigating the mechanistic pathways underlying noise-induced health effects are emerging. We review the current evidence regarding effects of noise on health and the related disease-mechanisms. Several high-quality cohort studies consistently found road traffic noise to be associated with a higher risk of ischemic heart disease, heart failure, diabetes, and all-cause mortality. Furthermore, recent studies have indicated that road traffic and railway noise may increase the risk of diseases not commonly investigated in an environmental noise context, including breast cancer, dementia, and tinnitus. The harmful effects of noise are related to activation of a physiological stress response and nighttime sleep disturbance. Oxidative stress and inflammation downstream of stress hormone signaling and dysregulated circadian rhythms are identified as major disease-relevant pathomechanistic drivers. We discuss the role of reactive oxygen species and present results from antioxidant interventions. Lastly, we provide an overview of oxidative stress markers and adverse redox processes reported for noise-exposed animals and humans. This position paper summarizes all available epidemiological, clinical, and preclinical evidence of transportation noise as an important environmental risk factor for public health and discusses its implications on the population level.

The intersection of social determinants of health, the microbiome, and health outcomes in immigrants: A scoping review

In the present scoping review, we explore whether existing evidence supports the premise that social determinants of health (SDoH) affect immigrant health outcomes through their effects on the microbiome. We adapt the National Institute on Minority Health and Health Disparities' research framework to propose a conceptual model that considers the intersection of SDoH, the microbiome, and health outcomes in immigrants. We use this conceptual model as a lens through which to explore recent research about SDoH, biological factors associated with changes to immigrants' microbiomes, and long-term health outcomes. In the 17 articles reviewed, dietary acculturation, physical activity, ethnicity, birthplace, age at migration and length of time in the host country, socioeconomic status, and social/linguistic acculturation were important determinants of postmigration microbiome-related transformations. These factors are associated with progressive shifts in microbiome profile with time in host country, increasing the risks for cardiometabolic, mental, immune, and inflammatory disorders and antibiotic resistance. The evidence thus supports the premise that SDoH influence immigrants' health postmigration, at least in part, through their effects on the microbiome. Omission of important postmigration social-ecological variables (e.g., stress, racism, social/family relationships, and environment), limited research among minoritized subgroups of immigrants, complexity and inter- and intra-individual differences in the microbiome, and limited interdisciplinary and biosocial collaboration restrict our understanding of this area of study. To identify potential microbiome-based interventions and promote immigrants' well-being, more research is necessary to understand the intersections of immigrant health with factors from the biological, behavioral/psychosocial, physical/built environment, and sociocultural environment domains at all social-ecological levels.

Vitamin B12 produced by gut bacteria modulates cholinergic signalling

A growing body of evidence indicates that gut microbiota influence brain function and behaviour. However, the molecular basis of how gut bacteria modulate host nervous system function is largely unknown. Here we show that vitamin B12-producing bacteria that colonize the intestine can modulate excitatory cholinergic signalling and behaviour in the host Caenorhabditis elegans. Here we demonstrate that vitamin B12 reduces cholinergic signalling in the nervous system through rewiring of the methionine (Met)/S-adenosylmethionine cycle in the intestine. We identify a conserved metabolic crosstalk between the methionine/S-adenosylmethionine cycle and the choline-oxidation pathway. In addition, we show that metabolic rewiring of these pathways by vitamin B12 reduces cholinergic signalling by limiting the availability of free choline required by neurons to synthesize acetylcholine. Our study reveals a gut-brain communication pathway by which enteric bacteria modulate host behaviour and may affect neurological health.

Chronic Stress as a Risk Factor for Type 2 Diabetes: Endocrine, Metabolic, and Immune Implications

BACKGROUND

Chronic stress is a condition of pressure on the brain and whole body, which in the long term may lead to a frank disease status, even including type 2 diabetes (T2D). Stress activates the hypothalamus-pituitary-adrenal axis with release of glucocorticoids (GCs) and catecholamines, as well as activation of the inflammatory pathway of the immune system, which alters glucose and lipid metabolism, ultimately leading to beta-cell destruction, insulin resistance and T2D onset. Alteration of the glucose and lipid metabolism accounts for insulin resistance and T2D outcome. Furthermore, stress-related subversion of the intestinal microbiota leads to an imbalance of the gut-brain-immune axis, as evidenced by the stress-related depression often associated with T2D. A condition of generalized inflammation and subversion of the intestinal microbiota represents another facet of stress-induced disease. In fact, chronic stress acts on the gut-brain axis with multiorgan consequences, as evidenced by the association between depression and T2D. Oxidative stress with the production of reactive oxygen species and cytokine-mediated inflammation represents the main hallmarks of chronic stress. ROS production and pro-inflammatory cytokines represent the main hallmarks of stress-related disorders, and therefore, the use of natural antioxidant and anti-inflammatory substances (nutraceuticals) may offer an alternative therapeutic approach to combat stress-related T2D. Single or combined administration of nutraceuticals would be very beneficial in targeting the neuro-endocrine-immune axis, thus, regulating major pathways involved in T2D onset. However, more clinical trials are needed to establish the effectiveness of nutraceutical treatment, dosage, time of administration and the most favorable combinations of compounds. Therefore, in view of their antioxidant and anti-inflammatory properties, the use of natural products or nutraceuticals for the treatment of stress-related diseases, even including T2D, will be discussed. Several evidences suggest that chronic stress represents one of the main factors responsible for the outcome of T2D.

Restraint stress-associated gastrointestinal injury and implications from the Evans blue-fed restraint stress mouse model

The association between stress and gastrointestinal (GI) tract diseases is well established, while the exact mechanism remains elusive. As a result, it is urgent to establish mouse models to investigate restraint stress-associated GI leakage, but current models have their limitations. A new Evans blue-fed restraint mouse model has recently been developed that allows researchers to study restraint stress-associated GI leakage in live animals. This review article will focus on this model, including its mechanisms, clinical implications, and applications for studying restraint stress-associated GI injury. Recent findings from studies using this model will also be highlighted, along with their potential for diagnosis and treatment. The article aims to discuss about current research and provide recommendations for further study, ultimately improving our understanding of the link between stress and GI injury and improving patient outcomes.

Changes of Intestinal Flora and the Effect on Intestinal Function in Infants With Ventricular Septal Defect After Cardiopulmonary Bypass Surgery

This study aimed to investigate the changes in intestinal flora in infants with ventricular septal defect (VSD) after cardiopulmonary bypass (CPB) surgery and their potential relationship with postoperative gastrointestinal function recovery. Fecal samples of 20 infants with VSD were collected before and after CPB surgery at our hospital from September 2021 to March 2022. 16S rRNA was used to detect and analyze the fecal samples. The most abundant intestinal microbes in the preoperative intestinal flora were Enterococcus (37.14%), Bifidobacterium (20.71%), Shigella (8.15%), Streptococcus (5.19%), Lactobacillus (3.7%), Rothia (2.22%). However, the most abundant intestinal microbes in the postoperative intestinal flora were Enterococcus (49.63%), Bifidobacterium (12.59%), Shigella (10.37%), Streptococcus (8.14%), Rothia (4.43%). The diversity and species richness of intestinal flora after CPB surgery were significantly lower than those preoperatively. The intestinal Enterococcus content in patients with postoperative gastrointestinal dysfunction was significantly higher than that in patients without gastrointestinal dysfunction (P < 0.05). Intestinal Bifidobacterium content in patients with postoperative gastrointestinal dysfunction was significantly lower than that in patients without gastrointestinal dysfunction (P < 0.05). After surgery, the content of intestinal Enterococcus was negatively correlated with the full feeding time, and the content of intestinal Bifidobacterium was positively correlated with full feeding time. After CPB surgery, the diversity and richness of intestinal flora decreased, intestinal pathogenic bacteria increased, and beneficial intestinal bacteria decreased. An increase in Enterococcus and decrease in Bifidobacterium can increase the incidence of gastrointestinal dysfunction and prolong the recovery time of gastrointestinal function.

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.

Maternal stress during the third trimester of pregnancy and the neonatal microbiome

OBJECTIVES

Preliminary research suggests that maternal prenatal stress may alter the development of the fetal microbiome and resulting microbial composition after birth. However, the findings of existing studies are mixed and inconclusive. The purpose of this exploratory study was to assess whether maternal stress during pregnancy is associated with the overall number and diversity of various microbial species in the infant gut microbiome or the abundance of specific bacterial taxa.

METHODS

Fifty-one women were recruited during their third trimester of pregnancy. The women completed a demographic questionnaire and Cohen's Perceived Stress Scale at recruitment. A stool sample was collected from their neonate at one month of age. Data on potential confounders, such as gestational age and mode of delivery, were extracted from medical records to control for their effects. 16s rRNA gene sequencing was used to identify the diversity and abundance of microbial species, along with multiple linear regression models to examine the effects of prenatal stress on microbial diversity. We employed negative binomial generalized linear models to test for differential expression of various microbial taxa among infants exposed to prenatal stress and those not exposed to prenatal stress.

RESULTS

More severe symptoms of prenatal stress were associated with a greater diversity of microbial species in the gut microbiome of neonates (β = .30, p = .025). Certain microbial taxa, such as Lactobacillus and Bifidobacterium, were enriched among infants exposed to greater maternal stress in utero, while others, such as Bacteroides and Enterobacteriaceae, were depleted in contrast to infants exposed to less stress.

CONCLUSIONS

Findings suggest that mild to moderate stress exposure in utero could be associated with a microbial environment in early life that is more optimally prepared to thrive in a stressful postnatal environment. Adaptation of gut microbiota under conditions of stress may involve upregulation of bacterial species, including certain protective microorganisms (e.g. Bifidobacterium), as well as downregulation of potential pathogens (e.g. Bacteroides) via epigenetic or other processes within the fetal/neonatal gut-brain axis. However, further research is needed to understand the trajectory of microbial diversity and composition as infant development proceeds and the ways in which both the structure and function of the neonatal microbiome may mediate the relationship between prenatal stress and health outcomes over time. These studies may eventually yield microbial markers and gene pathways that are biosignatures of risk or resilience and inform targets for probiotics or other therapies in utero or during the postnatal period.

High-altitude and low-altitude adapted chicken gut-microbes have different functional diversity

Recently, there has been considerable interest in the functions of gut microbiota in broiler chickens in relation to their use as feed additives. However, the gut-microbiota of chickens reared at different altitudes are not well documented for their potential role in adapting to prevailing conditions and functional changes. In this context, the present study investigates the functional diversity of gut-microbes in high-altitude (HACh) and low-altitude adapted chickens (LACh), assessing their substrate utilization profile through Biolog Ecoplates technology. This will help in the identification of potential microbes or their synthesized metabolites, which could be beneficial for the host or industrial applications. Results revealed that among the 31 different types of studied substrates, only polymers, carbohydrates, carboxylic acids, and amine-based substrates utilization varied significantly (p < 0.05) among the chickens reared at two different altitudes where gut-microbes of LACh utilized a broad range of substrates than the HACh. Further, diversity indices (Shannon and MacIntosh) analysis in LACh samples showed significant (p < 0.05) higher richness and evenness of microbes as compared to the HACh samples. However, no significant difference was observed in the Simpson diversity index in gut microbes of lowversus high-altitude chickens. In addition, the Principal Component Analysis elucidated variation in substrate preferences of gut-microbes, where 13 and 8 carbon substrates were found to constitute PC1 and PC2, respectively, where γ-aminobutyric acid, D-glucosaminic acid, i-erythritol and tween 40 were the most relevant substrates that had a major effect on PC1, however, alpha-ketobutyric acid and glycyl-L-glutamic acid affected PC2. Hence, this study concludes that the gut-microbes of high and low-altitudes adapted chickens use different carbon substrates so that they could play a vital role in the health and immunity of an animal host based on their geographical location. Consequently, this study substantiates the difference in the substrate utilization and functional diversity of the microbial flora in chickens reared at high and low altitudes due to altitudinal changes.

Lipids, Gut Microbiota, and the Complex Relationship with Alzheimer's Disease: A Narrative Review

Alzheimer's Disease (AD) is a multifactorial, progressive, and chronic neurodegenerative disorder associated with the aging process. Memory deficits, cognitive impairment, and motor dysfunction are characteristics of AD. It is estimated that, by 2050, 131.5 million people will have AD. There is evidence that the gastrointestinal microbiome and diet may contribute to the development of AD or act preventively. Communication between the brain and the intestine occurs through immune cells in the mucosa and endocrine cells, or via the vagus nerve. Aging promotes intestinal dysbiosis, characterized by an increase in pro-inflammatory pathogenic bacteria and a reduction in anti-inflammatory response-mediating bacteria, thus contributing to neuroinflammation and neuronal damage, ultimately leading to cognitive decline. Therefore, the microbiota-gut-brain axis has a significant impact on neurodegenerative disorders. Lipids may play a preventive or contributory role in the development of AD. High consumption of saturated and trans fats can increase cortisol release and lead to other chronic diseases associated with AD. Conversely, low levels of omega-3 polyunsaturated fatty acids may be linked to neurodegenerative diseases. Unlike other studies, this review aims to describe, in an integrative way, the interaction between the gastrointestinal microbiome, lipids, and AD, providing valuable insights into how the relationship between these factors affects disease progression, contributing to prevention and treatment strategies.

Protective Effects of Lacticaseibacillus rhamnosus IDCC3201 on Motor Functions and Anxiety Levels in a Chronic Stress Mouse Model

Growing evidence indicates a crucial role of the gut microbiota in physiological functions. Gut-brain axis imbalance has also been associated with neuropsychiatric and neurodegenerative disorders. Studies have suggested that probiotics regulate the stress response and alleviate mood-related symptoms. In this study, we investigated the effects of the probiotic Lacticaseibacillus rhamnosus IDCC3201 (L3201) on the behavioral response and fecal metabolite content in an unpredictable chronic mild stress (UCMS) mouse model. Our study shows that chronic stress in mice for three weeks resulted in significant changes in behavior, including lower locomotor activity, higher levels of anxiety, and depressive-like symptoms, compared to the control group. Metabolomic analysis demonstrated that disrupted fecal metabolites associated with aminoacyl-tRNA biosynthesis and valine, leucine, and isoleucine biosynthesis by UCMS were restored with the administration of L3201. Oral administration of the L3201 ameliorated the observed changes and improved the behavioral alterations along with fecal metabolites, suggesting that probiotics play a neuroprotective role.

High temperature stress induced oxidative stress, gut inflammation and disordered metabolome and microbiome in tsinling lenok trout

Tsinling lenok trout (Brachymystax lenok tsinlingensis Li) is a species of cold-water salmon that faces serious challenges due to global warming. High temperature stress has been found to damage the gut integrity of cold-water fish, impacting their growth and immunity. However, limited research exists on the causal relationship between gut microbial disturbance and metabolic dysfunction in cold-water fish induced by high temperature stress. To address this gap, we conducted a study to investigate the effects of high temperature stress (24 °C) on the gut tissue structure, antioxidant capacity, gut microorganisms, and metabolome reactions of tsinling lenok trout. Our analysis using 16 S rDNA gene sequencing revealed significant changes in the gut microbial composition and metabolic profile. Specifically, the abundance of Firmicutes and Gemmatimonadetes decreased significantly with increasing temperature, while the abundance of Bacteroidetes increased significantly. Metabolic analysis revealed a significant decrease in the abundance of glutathione, which is synthesized from glutamate and glycine, under high temperature stress. Additionally, there was a notable reduction in the levels of adenosine, inosine, xanthine, guanosine, and deoxyguanosine, which are essential for DNA/RNA synthesis. Conversely, there was a significant increase in the abundance of D-glucose 6 P. Furthermore, high temperature stress adversely affects intestinal structure and barrier function. Our findings provide valuable insights into the mechanism of high temperature stress in cold-water fish and serve as a foundation for future research aimed at mitigating the decline in production performance caused by such stress.

Extracellular Vesicles Released by Lactobacillus paracasei Mitigate Stress-induced Transcriptional Changes and Depression-like Behavior in Mice

Various probiotic strains have been reported to affect emotional behavior. However, the underlying mechanisms by which specific probiotic strains change brain function are not clearly understood. Here, we report that extracellular vesicles derived from Lactobacillus paracasei (Lpc-EV) have an ability to produce genome-wide changes against glucocorticoid (GC)-induced transcriptional responses in HT22 hippocampal neuronal cells. Genome-wide analysis using microarray assay followed by Rank-Rank Hypergeometric Overlap (RRHO) method leads to identify the top 20%-ranked 1,754 genes up- or down-regulated following GC treatment and their altered expressions are reversed by Lpc-EV in HT22 cells. Serial k-means clustering combined with Gene Ontology enrichment analyses indicate that the identified genes can be grouped into multiple functional clusters that contain functional modules of "responses to stress or steroid hormones", "histone modification", and "regulating MAPK signaling pathways". While all the selected genes respond to GC and Lpc-EV at certain levels, the present study focuses on the clusters that contain Mkp-1, Fkbp5, and Mecp2, the genes characterized to respond to GC and Lpc-EV in opposite directions in HT22 cells. A translational study indicates that the expression levels of Mkp-1, Fkbp5, and Mecp2 are changed in the hippocampus of mice exposed to chronic stress in the same directions as those following GC treatment in HT22 cells, whereas Lpc-EV treatment restored stress-induced changes of those factors, and alleviated stress-induced depressive-like behavior. These results suggest that Lpc-EV cargo contains bioactive components that directly induce genome-wide transcriptional responses against GC-induced transcriptional and behavioral changes.