Molecular modulation of intestinal epithelial barrier: contribution of microbiota

The disturbance of intestinal microbiome caused by the novel duck reovirus infection in Cherry Valley ducklings can induce intestinal damage

Novel duck reovirus disease is an infectious disease mainly caused by novel duck reovirus (NDRV), which is characterized by spleen necrosis and persistent diarrhea in ducks. However, the pathogenic mechanism of NDRV infection in Cherry Valley ducks remains unclear. To investigate the distribution of NDRV in the intestines of Cherry Valley ducks, intestinal morphogenesis, intestinal permeability, inflammatory cytokines, and the expression of tight junction proteins (TJPs), we introduced NDRV via intramuscular infection. The diversity and composition of ileum flora and content of short-chain fatty acids (SCFAs) were analyzed using Illumina MiSeq sequencing. The relationship between changes in the intestinal microbial community and intestinal damage in Cherry Valley ducks infected with NDRV was also assessed to offer new insights into the pathogenesis of NDRV and intestinal flora composition. The results showed that intestinal inflammation and barrier dysfunction occurred following NDRV infection. Additionally, a significant reduction in dominant bacterial species and a decrease in SCFA content within the intestinal microbiota led to weakened colonization resistance and the enrichment of opportunistic pathogens, exacerbating intestinal damage post-NDRV infection. Notably, TJPs and inflammatory cytokine disruptions were linked to a decline in SCFA-producing bacteria and an accumulation of pathogenic bacteria. In summary, changes in the ileum intestinal flora and disruptions to the intestinal barrier were associated with NDRV infection. Consequently, disturbances in intestinal flora caused by NDRV infection can lead to intestinal damage. These findings may offer us a new perspective, targeting the gut microbiota to better understand the progression of NDRV disease and investigate its underlying pathogenesis.

Role of immunomodulatory probiotics in alleviating bacterial diarrhea in piglets: a systematic review

Diarrhea is a common enteric disease in piglets that leads to high mortality and economic losses in swine production worldwide. Antibiotics are commonly used to prevent or treat diarrhea in piglets. However, irrational antibiotic use contributes to the development of resistance in bacteria and antibiotic residues in animal products, threatening public health, while causing gut microbiota dysbiosis and antibiotic-resistant bacterial infection in piglets. Therefore, the quest for alternative products (such as probiotics, prebiotics, organic acids, enzymes, essential oils, medium-chain fatty acids, zinc, and plant extracts) has recently been clearly emphasized through the increase in regulations regarding antibiotic use in livestock production. These antibiotic alternatives could lower the risk of antibiotic-resistant bacteria and meet consumer demand for antibiotic-free food. Several antibiotic alternatives have been proposed, including immunomodulatory probiotics, as candidates to reduce the need for antimicrobial therapy. Many studies have revealed that probiotics can avert and cure bacterial diarrhea by regulating the gut function and immune system of piglets. In this review, we focus on the major pathogenic bacteria causing piglet diarrhea, the research status of using probiotics to prevent and treat diarrhea, their possible mechanisms, and the safety issues related to the use of probiotics. Supplementation with probiotics is a possible alternative to antibiotics for the prevention or treatment of bacterial diarrhea in piglets. Furthermore, probiotics exert beneficial effects on feed efficiency and growth performance of piglets. Therefore, appropriate selection and strategies for the use of probiotics may have a positive effect on growth performance and also reduce diarrhea in piglets. This review provides useful information on probiotics for researchers, pig nutritionists, and the additive industry to support their use against bacterial diarrhea in piglets.

Is There an Interplay between Environmental Factors, Microbiota Imbalance, and Cancer Chemotherapy-Associated Intestinal Mucositis?

Interindividual variation in drug efficacy and toxicity is a significant problem, potentially leading to adverse clinical and economic public health outcomes. While pharmacogenetics and pharmacogenomics have long been considered the primary causes of such heterogeneous responses, pharmacomicrobiomics has recently gained attention. The microbiome, a community of microorganisms living in or on the human body, is a critical determinant of drug response and toxicity. Factors such as diet, lifestyle, exposure to xenobiotics, antibiotics use, illness, and genetics can influence the composition of the microbiota. Changes in the intestinal microbiota are particularly influential in drug responsiveness, especially in cancer chemotherapy. The microbiota can modulate an individual's response to a drug, affecting its bioavailability, clinical effect, and toxicity, affecting treatment outcomes and patient quality of life. For instance, the microbiota can convert drugs into active or toxic metabolites, influencing their efficacy and side effects. Alternatively, chemotherapy can also alter the microbiota, creating a bidirectional interplay. Probiotics have shown promise in modulating the microbiome and ameliorating chemotherapy side effects, highlighting the potential for microbiota-targeted interventions in improving cancer treatment outcomes. This opinion paper addresses how environmental factors and chemotherapy-induced dysbiosis impact cancer chemotherapy gastrointestinal toxicity.

Acupuncture influences multiple diseases by regulating gut microbiota

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

A guide to germ-free and gnotobiotic mouse technology to study health and disease

The intestinal microbiota has major influence on human physiology and modulates health and disease. Complex host-microbe interactions regulate various homeostatic processes, including metabolism and immune function, while disturbances in microbiota composition (dysbiosis) are associated with a plethora of human diseases and are believed to modulate disease initiation, progression and therapy response. The vast complexity of the human microbiota and its metabolic output represents a great challenge in unraveling the molecular basis of host-microbe interactions in specific physiological contexts. To increase our understanding of these interactions, functional microbiota research using animal models in a reductionistic setting are essential. In the dynamic landscape of gut microbiota research, the use of germ-free and gnotobiotic mouse technology, in which causal disease-driving mechanisms can be dissected, represents a pivotal investigative tool for functional microbiota research in health and disease, in which causal disease-driving mechanisms can be dissected. A better understanding of the health-modulating functions of the microbiota opens perspectives for improved therapies in many diseases. In this review, we discuss practical considerations for the design and execution of germ-free and gnotobiotic experiments, including considerations around germ-free rederivation and housing conditions, route and timing of microbial administration, and dosing protocols. This comprehensive overview aims to provide researchers with valuable insights for improved experimental design in the field of functional microbiota research.

Microbiome Dynamics: A Paradigm Shift in Combatting Infectious Diseases

Infectious diseases have long posed a significant threat to global health and require constant innovation in treatment approaches. However, recent groundbreaking research has shed light on a previously overlooked player in the pathogenesis of disease-the human microbiome. This review article addresses the intricate relationship between the microbiome and infectious diseases and unravels its role as a crucial mediator of host-pathogen interactions. We explore the remarkable potential of harnessing this dynamic ecosystem to develop innovative treatment strategies that could revolutionize the management of infectious diseases. By exploring the latest advances and emerging trends, this review aims to provide a new perspective on combating infectious diseases by targeting the microbiome.

Spirulina platensis as a growth booster for broiler; Insights into their nutritional, molecular, immunohistopathological, and microbiota modulating effects

BACKGROUND

The present study is designed to assess the effect of adding various doses of Spirulina platensis (SP) on broiler chicken growth performance, gut health, antioxidant biomarkers, cecal microbiota, histopathology, and immunohistochemistry of inducible nitric oxide synthase (iNOS). 240 male Cobb 500 broiler chicks (1 day old) were placed into four groups (sixty birds/group), then each group was further divided into three replicates of 20 chickens each for 35 days. Birds were allocated as follows; the 1st group (G1), the control group, fed on basal diet, the 2nd group (G2): basal diet plus SP (0.1%), the 3rd group (G3): basal diet plus SP (0.3%), and the 4th group (G4): basal diet plus SP (0.5%).

RESULTS

Throughout the trial (d 1 to 35), SP fortification significantly increased body weight growth (BWG) and feed conversion rate (FCR) (P < 0.05). Bursa considerably increased among the immunological organs in the Spirulina-supplemented groups. Within SP-supplemented groups, there was a substantial increase in catalase activity, blood total antioxidant capacity, jejunal superoxide dismutase (SOD), and glutathione peroxidase (GPX) activity (P < 0.05). Fatty acid binding protein 2 (FABP2), one of the gut barrier health biomarkers, significantly increased in the SP-supplemented groups but the IL-1β gene did not significantly differ across the groups (P < 0.05). Different organs in the control group showed histopathological changes, while the SP-supplemented chicken showed fewer or no signs of these lesions. The control group had higher levels of iNOS expression in the gut than the SP-supplemented groups (p < 0.05). Cecal Lactobacillus count significantly elevated with increasing the rate of SP inclusion rate (p < 0.05).

CONCLUSION

Supplementing broiler diets with SP, particularly at 0.5%, can improve productivity and profitability by promoting weight increase, feed utilization, antioxidant status, immunity, and gastrointestinal health.

The impact of exogenous vasoactive intestinal polypeptide on inflammatory responses and mRNA expression of tight junction genes in lambs fed a high-grain diet

This study assessed the impact of administering vasoactive intestinal polypeptide (VIP) on inflammation and intestinal VIP and tight junction mRNA expression in lambs fed grain-based finishing diets. Sixteen wether lambs (69.6 ± 1.9 kg) were individually housed, adapted to a corn-based diet containing no forage, and randomly assigned to 2 treatment groups. Lambs were intraperitoneally injected every other day for 28 d with either saline (0.9% NaCl) with no VIP (n = 8; control) or saline with VIP (n = 8; 1.3 nmol/kg BW). Blood samples were collected weekly for analysis of cytokine concentrations, and on days 0 and 28 for lipopolysaccharide (LPS), and LPS-binding protein (LBP) concentrations. Upon completion of the treatment period, lambs were euthanized and gastrointestinal tissues, including rumen, jejunum, cecum, and colon samples, were collected for analysis of the expression of tight junction mRNA (claudin-1, claudin-4, occludin, and ZO-1), endogenous VIP, and VIP receptor (VPAC-1). No treatment effects (P ≥ 0.38) were observed for VIP and VPAC-1 mRNA expression in the colon. Supplementation with VIP did not influence (P ≥ 0.28) the expression of claudin-1, claudin-4, occludin, and ZO-1 tight junction mRNA in the rumen, jejunum, cecum, and colon. Lambs treated with VIP had greater (P ≤ 0.01) plasma concentrations of the anti-inflammatory cytokines, IL-10 and IL-36RA. There were treatment-by-day interactions observed (P ≤ 0.02) for concentrations of the pro-inflammatory cytokines, MIP-1α and MIP-1β. Lambs that did not receive VIP had greater serum concentrations of LPS (P = 0.05) than the lambs receiving VIP. These data suggest that VIP administration may not influence tight junction mRNA expression but may decrease LPS concentrations and thus inflammation in lambs fed a grain-based diet.

Motility in Periweissella Species: Genomic and Phenotypic Characterization and Update on Motility in Lactobacillaceae

The genus Weissella and the recently described genus Periweissella, to which some previously named Weissella species have been reclassified as a result of a taxogenomic assessment, includes lactic acid bacteria species with high biotechnological and probiotic potential. Only one species, namely, Periweissella (P.) beninensis, whose type strain has been shown to possess probiotic features, has so far been described to be motile. However, the availability of numerous genome sequences of Weissella and Periweissella species prompted the possibility to screen for the presence of the genetic determinants encoding motility in Weissella and Periweissellas spp. other than P. beninensis. Herein, we performed a comprehensive genomic analysis to identify motility-related proteins in all Weissella and Periweissella species described so far, and extended the analysis to the recently sequenced Lactobacillaceae spp. Furthermore, we performed motility assays and transmission electron microscopy (TEM) on Periweissella type strains to confirm the genomic prediction. The homology-based analysis revealed genes coding for motility proteins only in the type strains of P. beninensis, P. fabalis, P. fabaria and P. ghanensis genomes. However, only the P. beninensis type strain was positive in the motility assay and displayed run-and-tumble behavior. Many peritrichous and long flagella on bacterial cells were visualized via TEM, as well. As for the Lactobacillaceae, in addition to the species previously described to harbor motility proteins, the genetic determinants of motility were also found in the genomes of the type strains of Lactobacillus rogosae and Ligilactobacillus salitolerans. This study, which is one of the first to analyze the genomes of Weissella, Periweissella and the recently sequenced Lactobacillaceae spp. for the presence of genes coding for motility proteins and which assesses the associated motility phenotypes, provides novel results that expand knowledge on these genera and are useful in the further characterization of lactic acid bacteria.

APE1/Ref-1 as a Therapeutic Target for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is characterized by chronic relapsing inflammation of the gastrointestinal tract. The prevalence of IBD is increasing with approximately 4.9 million cases reported worldwide. Current therapies are limited due to the severity of side effects and long-term toxicity, therefore, the development of novel IBD treatments is necessitated. Recent findings support apurinic/apyrimidinic endonuclease 1/reduction-oxidation factor 1 (APE1/Ref-1) as a target in many pathological conditions, including inflammatory diseases, where APE1/Ref-1 regulation of crucial transcription factors impacts significant pathways. Thus, a potential target for a novel IBD therapy is the redox activity of the multifunctional protein APE1/Ref-1. This review elaborates on the status of conventional IBD treatments, the role of an APE1/Ref-1 in intestinal inflammation, and the potential of a small molecule inhibitor of APE1/Ref-1 redox activity to modulate inflammation, oxidative stress response, and enteric neuronal damage in IBD.

Beer-gut microbiome alliance: a discussion of beer-mediated immunomodulation via the gut microbiome

As a long-established fermented beverage, beer is rich in many essential amino acids, vitamins, trace elements, and bioactive substances that are involved in the regulation of many human physiological functions. The polyphenols in the malt and hops of beer are also important active compounds that interact in both directions with the gut microbiome. This review summarizes the mechanisms by which polyphenols, fiber, and other beneficial components of beer are fermentatively broken down by the intestinal microbiome to initiate the mucosal immune barrier and thus participate in immune regulation. Beer degradation products have anti-inflammatory, anticoagulant, antioxidant, and glucolipid metabolism-modulating potential. We have categorized and summarized reported data on changes in disease indicators and in vivo gut microbiota abundance following alcoholic and non-alcoholic beer consumption. The positive effects of bioactive substances in beer in cancer prevention, reduction of cardiovascular events, and modulation of metabolic syndrome make it one of the candidates for microecological modulators.

The Interaction between Flavonoids and Intestinal Microbes: A Review

In recent years, research on the interaction between flavonoids and intestinal microbes have prompted a rash of food science, nutriology and biomedicine, complying with future research trends. The gut microbiota plays an essential role in the maintenance of intestinal homeostasis and human health, but once the intestinal flora dysregulation occurs, it may contribute to various diseases. Flavonoids have shown a variety of physiological activities, and are metabolized or biotransformed by gut microbiota, thereby producing new metabolites that promote human health by modulating the composition and structure of intestinal flora. Herein, this review demonstrates the key notion of flavonoids as well as intestinal microbiota and dysbiosis, aiming to provide a comprehensive understanding about how flavonoids regulate the diseases by gut microbiota. Emphasis is placed on the microbiota-flavonoid bidirectional interaction that affects the metabolic fate of flavonoids and their metabolites, thereby influencing their metabolic mechanism, biotransformation, bioavailability and bioactivity. Potentially by focusing on the abundance and diversity of gut microbiota as well as their metabolites such as bile acids, we discuss the influence mechanism of flavonoids on intestinal microbiota by protecting the intestinal barrier function and immune system. Additionally, the microbiota-flavonoid bidirectional interaction plays a crucial role in regulating various diseases. We explain the underlying regulation mechanism of several typical diseases including gastrointestinal diseases, obesity, diabetes and cancer, aiming to provide a theoretical basis and guideline for the promotion of gastrointestinal health as well as the treatment of diseases.

The intestinal barrier in disorders of the central nervous system

The intestinal barrier, which primarily consists of a mucus layer, an epithelial barrier, and a gut vascular barrier, has a crucial role in health and disease by facilitating nutrient absorption and preventing the entry of pathogens. The intestinal barrier is in close contact with gut microbiota on its luminal side and with enteric neurons and glial cells on its tissue side. Mounting evidence now suggests that the intestinal barrier is compromised not only in digestive disorders, but also in disorders of the central nervous system (CNS), such as Parkinson's disease, autism spectrum disorder, depression, multiple sclerosis, and Alzheimer's disease. After providing an overview of the structure and functions of the intestinal barrier, we review existing preclinical and clinical studies supporting the notion that intestinal barrier dysfunction is present in neurological, neurodevelopmental, and psychiatric disorders. On the basis of this evidence, we discuss the mechanisms that possibly link gut barrier dysfunction and CNS disorders and the potential impact that evaluating enteric barriers in brain disorders could have on clinical practice, in terms of novel diagnostic and therapeutic strategies, in the near future.

A pilot study characterizing longitudinal changes in fecal microbiota of patients with Hirschsprung-associated enterocolitis

PURPOSE

Hirschsprung disease is a neurointestinal disease that occurs due to failure of enteric neural crest-derived cells to complete their rostrocaudal migration along the gut mesenchyme, resulting in aganglionosis along variable lengths of the distal bowel. Despite the effective surgery that removes the aganglionic segment, children with Hirschsprung disease remain at high risk for developing a potentially life-threatening enterocolitis (Hirschsprung-associated enterocolitis). Although the etiology of this enterocolitis remains poorly understood, several recent studies in both mouse models and in human subjects suggest potential involvement of gastrointestinal microbiota in the underlying pathogenesis of Hirschsprung-associated enterocolitis.

METHODS

We present the first study to exploit the Illumina MiSeq next-generation sequencing platform within a longitudinal framework focused on microbiomes of Hirschsprung-associated enterocolitis in five patients. We analyzed bacterial communities from fecal samples collected at different timepoints starting from active enterocolitis and progressing into remission.

RESULTS

We observed compositional differences between patients largely attributable to variability in age at the time of sample collection. Remission samples across patients exhibited compositional similarity, including enrichment of Blautia, while active enterocolitis samples showed substantial variability in composition.

CONCLUSIONS

Overall, our findings provide continued support for the role of GI microbiota in the pathogenesis of Hirschsprung-associated enterocolitis.

Effects of Low-Ambient-Temperature Stimulation on Modifying the Intestinal Structure and Function of Different Pig Breeds

Simple Summary

Low ambient temperature resulted in the body’s cold stress response, while local wild boars in the middle-temperate zone performed better than commercial pigs. Therefore, three breeds—Large White (LW) pigs, a local Mashen (MS) pig breed and Jinfen White (JFW) pigs, a hybrid breed from wild boar—were investigated in an artificial climate chamber. The results implicated that low-ambient-temperature stimulation increased trypsin activity in duodenal chyme and promoted inflammatory response in Mashen pigs. The cold-resistance mechanism of MS pigs should be explored to reduce hogs’ stress caused by low-ambient-temperature stimulation.

Abstract

Ambient temperature (Ta) fluctuation is a key factor affecting the growth performance and economic returns of pigs. However, whether the response of intestinal structure and function are related to pig breeds in low Ta has not been investigated yet. In this study, Large White (LW) pigs, Jinfen White (JFW) pigs and Mashen (MS) pigs were raised in artificial climate chambers under normal Ta (25 °C) and low Ta (4 °C) for 96 h. Afterwards, the decrease in body temperature and complete blood counts (CBC) of all pigs were measured. Hematoxylin–eosin, immunohistochemical staining, qPCR and ELISA were used to investigate their intestinal mucosa integrity and inflammatory response. The results showed that MS pigs could maintain a normal body temperature and villus structure after 4 °C stimulation compared with those of LW and JFW pigs. Villus height and villus height/crypt depth of MS pigs were significantly higher than those of LW and JFW pigs at 4 °C. Low-Ta stimulation increased the digestion of carbohydrates of all pigs. Meanwhile, low Ta enhanced the activity of lipase in LW pigs and increased trypsin activity in MS and JFW pigs. Furthermore, low-Ta stimulation significantly downregulated the protein of tight junction and upregulated the mRNA expression of inflammatory cytokines in MS pigs. MS pigs also showed stronger spleen immune function at 4 °C. These results indicated that the local MS pig breed had stronger intestinal function in low Ta by producing a stronger inflammatory response, which lays the foundation for further study on the mechanism of cold tolerance in pigs.

Paradigm Shift in Phytochemicals Research: Evolution from Antioxidant Capacity to Anti-Inflammatory Effect and to Roles in Gut Health and Metabolic Syndrome

Food bioactive components, particularly phytochemicals with antioxidant capacity, have been extensively studied over the past two decades. However, as new analytical and molecular biological tools advance, antioxidants related research has undergone significant paradigm shifts. This review is a high-level overview of the evolution of phytochemical antioxidants research. Early research used chemical models to assess the antioxidant capacity of different phytochemicals, which provided important information about the health potential, but the results were overused and misinterpreted despite the lack of biological relevance (Antioxidants v1.0). This led to findings in the anti-inflammatory properties and modulatory effects of cell signaling of phytochemicals (Antioxidants v2.0). Recent advances in the role of diet in modulating gut microbiota have suggested a new phase of food bioactives research along the phytochemicals-gut microbiota-intestinal metabolites-low-grade inflammation-metabolic syndrome axis (Antioxidants v3.0). Polyphenols and carotenoids were discussed in-depth, and future research directions were also provided.

How do intestinal probiotics restore the intestinal barrier?

The intestinal barrier is a structure that prevents harmful substances, such as bacteria and endotoxins, from penetrating the intestinal wall and entering human tissues, organs, and microcirculation. It can separate colonizing microbes from systemic tissues and prevent the invasion of pathogenic bacteria. Pathological conditions such as shock, trauma, stress, and inflammation damage the intestinal barrier to varying degrees, aggravating the primary disease. Intestinal probiotics are a type of active microorganisms beneficial to the health of the host and an essential element of human health. Reportedly, intestinal probiotics can affect the renewal of intestinal epithelial cells, and also make cell connections closer, increase the production of tight junction proteins and mucins, promote the development of the immune system, regulate the release of intestinal antimicrobial peptides, compete with pathogenic bacteria for nutrients and living space, and interact with the host and intestinal commensal flora to restore the intestinal barrier. In this review, we provide a comprehensive overview of how intestinal probiotics restore the intestinal barrier to provide new ideas for treating intestinal injury-related diseases.

Integrating the Gut Microbiome and Stress-Diathesis to Explore Post-Trauma Recovery: An Updated Model

Musculoskeletal conditions of traumatic and non-traumatic origin represent an ongoing health challenge. While the last three decades have seen significant advancement in our understanding of musculoskeletal conditions, the mechanisms of a delayed or lack of recovery are still a mystery. Here, we present an expansion of the integrated stress-diathesis model through the inclusion of the gut microbiome. Connecting the microbiome with known adverse neurobiologic, microbiologic and pathophysiologic sequelae following an injury, trauma or stressful event may help improve our knowledge of the pathogenesis of poor recovery. Such knowledge could provide a foundation for the exploration and development of more effective interventions to prevent the transition from acute to chronic pain.

The Role of Probiotics in Alleviating Postweaning Diarrhea in Piglets From the Perspective of Intestinal Barriers

Early weaning of piglets is an important strategy for improving the production efficiency of sows in modern intensive farming systems. However, due to multiple stressors such as physiological, environmental and social challenges, postweaning syndrome in piglets often occurs during early weaning period, and postweaning diarrhea (PWD) is a serious threat to piglet health, resulting in high mortality. Early weaning disrupts the intestinal barrier function of piglets, disturbs the homeostasis of gut microbiota, and destroys the intestinal chemical, mechanical and immunological barriers, which is one of the main causes of PWD in piglets. The traditional method of preventing PWD is to supplement piglet diet with antibiotics. However, the long-term overuse of antibiotics led to bacterial resistance, and antibiotics residues in animal products, threatening human health while causing dysbiosis of gut microbiota and superinfection of piglets. Antibiotic supplementation in livestock diets is prohibited in many countries and regions. Regarding this context, finding antibiotic alternatives to maintain piglet health at the critical weaning period becomes a real emergency. More and more studies showed that probiotics can prevent and treat PWD by regulating the intestinal barriers in recent years. Here, we review the research status of PWD-preventing and treating probiotics and discuss its potential mechanisms from the perspective of intestinal barriers (the intestinal microbial barrier, the intestinal chemical barrier, the intestinal mechanical barrier and the intestinal immunological barrier) in piglets.

Focus on the Role of the NLRP3 Inflammasome in Multiple Sclerosis: Pathogenesis, Diagnosis, and Therapeutics

Neuroinflammation is initiated with an aberrant innate immune response in the central nervous system (CNS) and is involved in many neurological diseases. Inflammasomes are intracellular multiprotein complexes that can be used as platforms to induce the maturation and secretion of proinflammatory cytokines and pyroptosis, thus playing a pivotal role in neuroinflammation. Among the inflammasomes, the nucleotide-binding oligomerization domain-, leucine-rich repeat- and pyrin domain-containing 3 (NLRP3) inflammasome is well-characterized and contributes to many neurological diseases, such as multiple sclerosis (MS), Alzheimer's disease (AD), and ischemic stroke. MS is a chronic autoimmune disease of the CNS, and its hallmarks include chronic inflammation, demyelination, and neurodegeneration. Studies have demonstrated a relationship between MS and the NLRP3 inflammasome. To date, the pathogenesis of MS is not fully understood, and clinical studies on novel therapies are still underway. Here, we review the activation mechanism of the NLRP3 inflammasome, its role in MS, and therapies targeting related molecules, which may be beneficial in MS.

Intestinal Barrier Dysfunction in Fatty Liver Disease: Roles of Microbiota, Mucosal Immune System, and Bile Acids

Nonalcoholic fatty liver disease (NAFLD) describes a spectrum of progressive liver diseases ranging from simple steatosis to steatohepatitis and fibrosis. Globally, NAFLD is the leading cause of morbidity and mortality associated with chronic liver disease, and NAFLD patients are at a higher risk of developing cirrhosis and hepatocellular carcinoma. While there is a consensus that inflammation plays a key role in promoting NAFLD progression, the underlying mechanisms are not well understood. Recent clinical and experimental evidence suggest that increased hepatic translocation of gut microbial antigens, secondary to diet-induced impairment of the intestinal barrier may be important in driving hepatic inflammation in NAFLD. Here, we briefly review various endogenous and exogenous factors influencing the intestinal barrier and present recent advances in our understanding of cellular and molecular mechanisms underlying intestinal barrier dysfunction in NAFLD.

Implementing organ-on-chip in a next-generation risk assessment of chemicals: a review

Organ-on-chip (OoC) technology is full of engineering and biological challenges, but it has the potential to revolutionize the Next-Generation Risk Assessment of novel ingredients for consumer products and chemicals. A successful incorporation of OoC technology into the Next-Generation Risk Assessment toolbox depends on the robustness of the microfluidic devices and the organ tissue models used. Recent advances in standardized device manufacturing, organ tissue cultivation and growth protocols offer the ability to bridge the gaps towards the implementation of organ-on-chip technology. Next-Generation Risk Assessment is an exposure-led and hypothesis-driven tiered approach to risk assessment using detailed human exposure information and the application of appropriate new (non-animal) toxicological testing approaches. Organ-on-chip presents a promising in vitro approach by combining human cell culturing with dynamic microfluidics to improve physiological emulation. Here, we critically review commercial organ-on-chip devices, as well as recent tissue culture model studies of the skin, intestinal barrier and liver as the main metabolic organ to be used on-chip for Next-Generation Risk Assessment. Finally, microfluidically linked tissue combinations such as skin-liver and intestine-liver in organ-on-chip devices are reviewed as they form a relevant aspect for advancing toxicokinetic and toxicodynamic studies. We point to recent achievements and challenges to overcome, to advance non-animal, human-relevant safety studies.

Circadian Rhythms, the Gut Microbiome, and Metabolic Disorders

The circadian clock and gut microbiome play integral roles in preserving metabolic homeostasis. Circadian rhythms represent an endogenous time-keeping system that regulates cell and organ functions and synchronizes physiology with external cues to establish metabolic homeostasis. A variety of functions throughout the gastrointestinal tract and liver are under circadian control, including nutrient transport, processing, and detoxification. The gut microbiota also plays an essential role in host metabolism, regulating processes such as digestion, inflammatory modulation, and bile acid metabolism. Both the circadian clock and the gut microbiota influence each other in a reciprocal fashion, as gut dysbiosis can precipitate circadian asynchrony, and vice-versa. Disruption of either system impacts homeostasis in a bidirectional manner and can contribute to metabolic dysfunction. Evidence suggests such disruptions can lead to the development of metabolic diseases, including obesity, diabetes, nonalcoholic fatty liver disease, cirrhosis, and hepatocellular carcinoma. This review will provide a basic overview of the circadian and gut microbial systems, how they are intertwined, and their impact on the liver and gastrointestinal tract and in the development of metabolic disease. Particular areas of discussion include epigenetic regulation of circadian pathways as well as a mechanistic overview of microbial dysbiosis. In addition, therapeutic targets of these systems, including dietary modifications, behavioral modifications, and microbial-directed therapies, will be explored.

Implication of Intestinal Barrier Dysfunction in Gut Dysbiosis and Diseases

The intestinal mucosal barrier, also referred to as intestinal barrier, is widely recognized as a critical player in gut homeostasis maintenance as it ensures the complex crosstalk between gut microbes (both commensals and pathogens) and the host immune system. Highly specialized epithelial cells constantly cope with several protective and harmful agents to maintain the multiple physiological functions of the barrier as well as its integrity. However, both genetic defects and environmental factors can break such equilibrium, thus promoting gut dysbiosis, dysregulated immune-inflammatory responses, and even the development of chronic pathological conditions. Here, we review and discuss the molecular and cellular pathways underlying intestinal barrier structural and functional homeostasis, focusing on potential alterations that may undermine this fine balance.

Intestinal Permeability, Dysbiosis, Inflammation and Enteric Glia Cells: The Intestinal Etiology of Parkinson’s Disease

The scientific and medical communities are becoming more aware of the substantial relationship between the function of the central nervous system (CNS) and the state of the gut environment. Parkinson's disease (PD) is a neurodegenerative disorder that affects the nigrostriatal pathway in the midbrain, presenting not only motor symptoms but also various non-motor manifestations, including neuropsychiatric symptoms and gastrointestinal (GI) symptoms. Over time, our knowledge of PD has progressed from the detection of midbrain dopaminergic deficits to the identification of a multifaceted disease with a variety of central and peripheral manifestations, with increased attention to the intestinal tract. Accumulating evidence has revealed that intestinal disorders are not only the peripheral consequence of PD pathogenesis, but also the possible pathological initiator decades before it progresses to the CNS. Here, we summarized recent research findings on the involvement of the intestinal environment in PD, with an emphasis on the involvement of the intestinal barrier, microbiome and its metabolites, inflammation, and enteric glial cells

Evaluation of the Function of Probiotics, Emphasizing the Role of their Binding to the Intestinal Epithelium in the Stability and their Effects on the Immune System

Due to the importance of using cost-effective methods for therapeutic purposes, the function of probiotics as safe microorganisms and the study of their relevant functional mechanisms have recently been in the spotlight. Finding the mechanisms of attachment and stability and their beneficial effects on the immune system can be useful in identifying and increasing the therapeutic effects of probiotics. In this review, the functional mechanisms of probiotics were comprehensively investigated. Relevant articles were searched in scientific sources, documents, and databases, including PubMed, NCBI, Bactibace, OptiBac, and Bagel4. The most important functional mechanisms of probiotics and their effects on strengthening the epithelial barrier, competitive inhibition of pathogenic microorganisms, production of antimicrobials, binding and interaction with the host, and regulatory effects on the immune system were discussed.

In this regard, the attachment of probiotics to the epithelium is very important because the prerequisite for their proper functioning is to establish a proper connection to the epithelium. Therefore, more attention should be paid to the binding effect of probiotics, including sortase A, a significant factor involved in the expression of sortase-dependent proteins (SDP), on their surface as mediators of intestinal epithelial cell binding. In general, by investigating the functional mechanisms of probiotics, it was concluded that the mechanism by which probiotics regulate the immune system and adhesion capacity can directly and indirectly have preventive and therapeutic effects on a wide range of diseases. However, further study of these mechanisms requires extensive research on various aspects.

Microbiota-gut-brain axis: enteroendocrine cells and the enteric nervous system form an interface between the microbiota and the central nervous system

The microbiota-gut-brain axis transmits bidirectional communication between the gut and the central nervous system and links the emotional and cognitive centers of the brain with peripheral gut functions. This communication occurs along the axis via local, paracrine, and endocrine mechanisms involving a variety of gut-derived peptide/amine produced by enteroendocrine cells. Neural networks, such as the enteric nervous system, and the central nervous system, including the autonomic nervous system, also transmit information through the microbiota-gut-brain axis. Recent advances in research have described the importance of the gut microbiota in influencing normal physiology and contributing to disease. We are only beginning to understand this bidirectional communication system. In this review, we summarize the available data supporting the existence of these interactions, highlighting data related to the contribution of enteroendocrine cells and the enteric nervous system as an interface between the gut microbiota and brain.

The Role of Leaky Gut in Nonalcoholic Fatty Liver Disease: A Novel Therapeutic Target

The liver directly accepts blood from the gut and is, therefore, exposed to intestinal bacteria. Recent studies have demonstrated a relationship between gut bacteria and nonalcoholic fatty liver disease (NAFLD). Approximately 10–20% of NAFLD patients develop nonalcoholic steatohepatitis (NASH), and endotoxins produced by Gram-negative bacilli may be involved in NAFLD pathogenesis. NAFLD hyperendotoxicemia has intestinal and hepatic factors. The intestinal factors include impaired intestinal barrier function (leaky gut syndrome) and dysbiosis due to increased abundance of ethanol-producing bacteria, which can change endogenous alcohol concentrations. The hepatic factors include hyperleptinemia, which is associated with an excessive response to endotoxins, leading to intrahepatic inflammation and fibrosis. Clinically, the relationship between gut bacteria and NAFLD has been targeted in some randomized controlled trials of probiotics and other agents, but the results have been inconsistent. A recent randomized, placebo-controlled study explored the utility of lubiprostone, a treatment for constipation, in restoring intestinal barrier function and improving the outcomes of NAFLD patients, marking a new phase in the development of novel therapies targeting the intestinal barrier. This review summarizes recent data from studies in animal models and randomized clinical trials on the role of the gut–liver axis in NAFLD pathogenesis and progression.

Probiotics in the management of Giardia duodenalis: an update on potential mechanisms and outcomes

Giardia duodenalis is a common cause of infection in children and travelers. The most frequent symptom is diarrhea in these patients. G. duodenalis trophozoites use a highly specialized adhesive disc to attach the host intestinal epithelium to induce intestinal damages. Pathological features of the small intestine following giardiasis include villous atrophy; infiltration of granulocytes, lymphocytes, and plasma cells into the lamina propria; and nodular lymphoid hyperplasia. The disturbed intestinal microbiota has been observed in patients with giardiasis. Therefore, a growing body of evidence has emphasized restoring the gut microbiome by probiotics in giardiasis. This study aimed to review the literature to find the pathologic features of giardiasis and its relationship with imbalanced microbiota. Then, benefits of probiotics in giardiasis and their potential molecular mechanisms were discussed. It has been illustrated that using probiotics (e.g., Lactobacillus and Saccharomyces) can reduce the time of gastrointestinal symptoms and repair the damages, particularly in giardiasis. Probiotics' capability in restoring the composition of commensal microbiota may lead to therapeutic outcomes. According to preclinical and clinical studies, probiotics can protect against parasite-induced mucosal damages via increasing the antioxidant capacity, suppressing oxidative products, and regulating the systemic and mucosal immune responses. In addition, they can reduce the proportion of G. duodenalis load by directly targeting the parasite. They can destroy the cellular architecture of parasites and suppress the proliferation and growth of trophozoites via the production of some factors with anti-giardial features. Further researches are required to find suitable probiotics for the prevention and treatment of giardiasis.

Maternal and neonatal canine cortisol measurement in multiple matrices during the perinatal period: A pilot study

Stress exposure during perinatal period may lead to maternal cortisol increase that negatively affects the offspring development. In recent years, the interest on non-invasive sampling methods to measure cortisol as a marker of stress is increasing in both humans and animals. Indeed, discomfort due to blood collection may compromise the diagnostic outcome, mainly in uncooperative patients. So far, some alternative matrices but not milk have been explored in adult dogs, while no data are available on the neonate and paediatric live pups. This study aimed to measure cortisol concentration in different biological substrates in both dams (blood, saliva, hair and milk) and pups (saliva and hair) at established times from proestrus up to two months after parturition. For this purpose, five female German shepherd bitches and their 22 pups were enrolled. Cortisol concentration was assessed using the enzyme immunoassay kit (Salivary Cortisol ELISA kit, Salimetrics) after matrices appropriate preparation if required. Cortisol was measurable in all the substrates, except some milk samples below the detection limit. Maternal cortisol concentrations differed among the matrices (P <0.0001) with the highest values recorded in plasma (median 0.596 μg/dL) compared to saliva (median 0.159 μg/dL), hair (median 0.083 μg/dL) and milk (median 0.045 μg/dL). Cortisol in dams did not vary within the same matrix over time. In pups, salivary (median 0.295 μg/dL) cortisol was always higher than hair (median 0.049 μg/dL; P <0.0001). At birth (P = 0.01) and two months later (P = 0.05), neonatal salivary cortisol was higher compared to other samplings. The present study demonstrates the suitability of these innovative substrates for cortisol measurement, suggesting them as potential diagnostic support in canine neonatology and welfare.

Analysis of jejunum microbiota of HFD/STZ diabetic rats

Currently, several studies propose that the dominant intestinal bacteria are core flora. Besides keeping the homeostasis of the intestinal environment, the intestinal microflora also plays a role in body metabolism, production of some vitamins, and control of barrier function. The study aimed to investigate the jejunum microbiota in diabetic rats as well as it's the relationship with Ceftriaxone sodium-mediated gut dysbiosis, diabetic parameters, and intestinal permeability. Thirty-two Wistar rats (Male) were enrolled and divided into four groups (A, B, C, and D; N = 8). Subsequently, T2DM was induced in C and D groups by HFD/STZ model and then gut dysbiosis in B and D groups via intragastric administration of Ceftriaxone sodium for two weeks. The food-water intake, body weight, fasting blood glucose, plasma insulin, HOMA-IR, intestinal permeability, and jejunum microbiota and it's histology were investigated. In this study, T2DM was associated with a significant decrease in the richness and diversity of jejunum microbiota, elevation in the intestinal permeability, and higher abundance of some opportunistic pathogens. Ceftriaxone sodium-induced gut dysbiosis declined food-water intake, damagedthe villi of jejunum tissue, increased intestinal permeability, and affected the diversity of jejunum microbiota. In diabetic rats, Ceftriaxone sodium-mediated gut dysbiosis also declined the abundance of someSCFAs bacteria and raised the abundant of some opportunistic bacteria such as Staphylococcus_sciuri. Interestingly, we found that several bacteria were negatively correlated with HOMA-IR, fasting blood glucose, body weight, and intestinal permeability. Overall, the study highlighted the jejunum microflora alterations in HFD/STZ diabetic rats and assessed the effect of Ceftriaxone sodium-induced gut dysbiosis on diabetic parameters, jejunum microbiota and histology, and intestinal permeability, which are of potential for further studies.

The gut microbiota is associated with the small intestinal paracellular permeability and the development of the immune system in healthy children during the first two years of life

BACKGROUND

The intestinal barrier plays an important role in the defense against infections, and nutritional, endocrine, and immune functions. The gut microbiota playing an important role in development of the gastrointestinal tract can impact intestinal permeability and immunity during early life, but data concerning this problem are scarce.

METHODS

We analyzed the microbiota in fecal samples (101 samples in total) collected longitudinally over 24 months from 21 newborns to investigate whether the markers of small intestinal paracellular permeability (zonulin) and immune system development (calprotectin) are linked to the gut microbiota. The results were validated using data from an independent cohort that included the calprotectin and gut microbiota in children during the first year of life.

RESULTS

Zonulin levels tended to increase for up to 6 months after childbirth and stabilize thereafter remaining at a high level while calprotectin concentration was high after childbirth and began to decline from 6 months of life. The gut microbiota composition and the related metabolic potentials changed during the first 2 years of life and were correlated with zonulin and calprotectin levels. Faecal calprotectin correlated inversely with alpha diversity (Shannon index, r = - 0.30, FDR P (Q) = 0.039). It also correlated with seven taxa; i.a. negatively with Ruminococcaceae (r = - 0.34, Q = 0.046), and Clostridiales (r = - 0.34, Q = 0.048) and positively with Staphylococcus (r = 0.38, Q = 0.023) and Staphylococcaceae (r = 0.35, Q = 0.04), whereas zonulin correlated with 19 taxa; i.a. with Bacillales (r = - 0.52, Q = 0.0004), Clostridiales (r = 0.48, Q = 0.001) and the Ruminococcus (torques group) (r = 0.40, Q = 0.026). When time intervals were considered only changes in abundance of the Ruminococcus (torques group) were associated with changes in calprotectin (β = 2.94, SE = 0.8, Q = 0.015). The dynamics of stool calprotectin was negatively associated with changes in two MetaCyc pathways: pyruvate fermentation to butanoate (β = - 4.54, SE = 1.08, Q = 0.028) and Clostridium acetobutylicum fermentation (β = - 4.48, SE = 1.16, Q = 0.026).

CONCLUSIONS

The small intestinal paracellular permeability, immune system-related markers and gut microbiota change dynamically during the first 2 years of life. The Ruminococcus (torques group) seems to be especially involved in controlling paracellular permeability. Staphylococcus, Staphylococcaceae, Ruminococcaceae, and Clostridiales, may be potential biomarkers of the immune system. Despite observed correlations their clear causation and health consequences were not proven. Mechanistic studies are required.

Potential Mechanisms Linking Food-Derived MicroRNAs, Gut Microbiota and Intestinal Barrier Functions in the Context of Nutrition and Human Health

MicroRNAs (miRNAs) are non-coding single-stranded RNA molecules from 18 to 24 nucleotides that are produced by prokaryote and eukaryote organisms, which play a crucial role in regulating gene expression through binding to their mRNA targets. MiRNAs have acquired special attention for their potential in cross kingdom communication, notably food-derived microRNAs (xenomiRs), which could have an impact on microorganism and mammal physiology. In this review, we mainly aim to deal with new perspectives on: (1) The mechanism by which food-derived xenomiRs (mainly dietary plant xenomiRs) could be incorporated into humans through diet, in a free form, associated with proteins or encapsulated in exosome-like nanoparticles. (2) The impact of dietary plant-derived miRNAs in modulating gut microbiota composition, which in turn, could regulate intestinal barrier permeability and therefore, affect dietary metabolite, postbiotics or food-derived miRNAs uptake efficiency. Individual gut microbiota signature/composition could be also involved in xenomiR uptake efficiency through several mechanisms such us increasing the bioavailability of exosome-like nanoparticles miRNAs. (3) Gut microbiota dysbiosis has been proposed to contribute to disease development by affecting gut epithelial barrier permeability. For his reason, the availability and uptake of dietary plant xenomiRs might depend, among other factors, on this microbiota-related permeability of the intestine. We hypothesize and critically review that xenomiRs-microbiota interaction, which has been scarcely explored yet, could contribute to explain, at least in part, the current disparity of evidences found dealing with dietary miRNA uptake and function in humans. Furthermore, dietary plant xenomiRs could be involved in the establishment of the multiple gut microenvironments, in which microorganism would adapt in order to optimize the resources and thrive in them. Additionally, a particular xenomiR could preferentially accumulate in a specific region of the gastrointestinal tract and participate in the selection and functions of specific gut microbial communities.

An altered gut microbiota in duck-origin parvovirus infection on cherry valley ducklings is associated with mucosal barrier dysfunction

Duck-origin parvovirus disease is an epidemic disease mainly caused by duck-origin goose parvovirus (D-GPV), which is characterized by beak atrophy and dwarfism syndrome. Its main symptoms are persistent diarrhea, skeletal dysplasia, and growth retardation. However, the pathogenesis of Cherry Valley ducks infected by D-GPV has not been studied thoroughly. To perceive the distribution of D-GPV in the intestinal tract, intestinal morphological development, intestinal permeability, inflammatory cytokines in Cherry Valley ducks, and expression of tight junction protein, the D-GPV infection was given intramuscularly. Illumina MiSeq sequencing technology was used to analyze the diversity and structure of ileum flora and content of short-chain fatty acids of its metabolites. To investigate the relationship between intestinal flora changes and intestinal barrier function after D-GPV infection on Cherry Valley ducks is of great theoretical and practical significance for further understanding the pathogenesis of D-GPV and the structure of intestinal flora in ducks. The results showed that D-GPV infection was accompanied by intestinal inflammation and barrier dysfunction. At this time, the decrease of a large number of beneficial bacteria and the content of short-chain fatty acids in intestinal flora led to the weakening of colonization resistance of the intestinal flora and the accumulation of potentially pathogenic bacteria, which would aggravate the negative effect of D-GPV damage to the intestinal tract. Furthermore, a significant increase in Unclassified_S24-7 and decrease in Streptococcus was observed in D-GPV persistent, indicating the disruption in the structure of gut microbiota. Notably, the shift of microbiota was associated with the transcription of tight-junction protein and immune-associated cytokines. These results indicate that altered ileum microbiota, intestinal barrier, and immune dysfunction are associated with D-GPV infection. Therefore, there is a relationship between the intestinal barrier dysfunction and dysbiosis caused by D-GPV, but the specific mechanism needs to be further explored.

Endotoxins and Non-Alcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. It occurs with a prevalence of up to 25%, of which 10-20% cases progress to nonalcoholic steatohepatitis (NASH), cirrhosis, and liver cancer. The histopathology of NASH is characterized by neutrophilic infiltration, and endotoxins from gram-negative rods have been postulated as a contributing factor. Elevations in endotoxin levels in the blood can be classified as intestinal and hepatic factors. In recent years, leaky gut syndrome, which is characterized by impaired intestinal barrier function, has become a significant issue. A leaky gut may prompt intestinal bacteria dysbiosis and increase the amount of endotoxin that enters the liver from the portal vein. These contribute to persistent chronic inflammation and progressive liver damage. In addition, hepatic factors suggest that liver damage can be induced by low-dose endotoxins, which does not occur in healthy individuals. In particular, increased expression of CD14, an endotoxin co-receptor in the liver, may result in leptin-induced endotoxin hyper-responsiveness in obese individuals. Thus, elevated blood endotoxin levels contribute to the progression of NASH. The current therapeutic targets for NASH treat steatosis and liver inflammation and fibrosis. While many clinical trials are underway, no studies have been performed on therapeutic agents that target the intestinal barrier. Recently, a randomized placebo-controlled trial examined the role of the intestinal barrier in patients with NAFLD. To our knowledge, this study was the first of its kind and study suggested that the intestinal barrier may be a novel target in the future treatment of NAFLD.

Targeting Mitogen-Activated Protein Kinases by Natural Products: A Novel Therapeutic Approach for Inflammatory Bowel Diseases

An increase in the prevalence of Inflammatory Bowel Diseases (IBD) as a multifactorial intestinal chronic inflammation as well as the absence of a certain cure, has created an innovative era in the management of IBD by molecule/pathway-based anti-inflammatory approaches. There are credible documentations that demonstrate Mitogen-Activated Protein Kinases (MAPK) acts as IBD regulator. Upon the activation of MAPK signalling pathway, the transcription and expression of various encoding inflammatory molecules implicated in IBD are altered, thereby exacerbating the inflammation development. The current pharmacological management of IBD, including drug and biological therapies are expensive, possess temporary relief and some adverse effects. In this context, a variety of dietary fruits or medicinal herbs have received worldwide attention versus the development of IBD. Infact, natural ingredients, such as Flavaglines, Fisetin, Myricitrin, Cardamonin, Curcumin, Octacosanol and Mangiferin possess protective and therapeutic effects against IBD via modulation of different segments of MAPK signaling pathway. This review paper calls attention to the role of MAPK signaling triggered by natural products in the prevention and treatment of IBD.

Gut Microbiota-Bile Acid Crosstalk in Diarrhea-Irritable Bowel Syndrome

The occurrence of diarrhea-predominant irritable bowel syndrome (IBS-D) is the result of multiple factors, and its pathogenesis has not yet been clarified. Emerging evidence indicates abnormal changes in gut microbiota and bile acid (BA) metabolism have a close relationship with IBS-D. Gut microbiota is involved in the secondary BA production via deconjugation, 7α-dehydroxylation, oxidation, epimerization, desulfation, and esterification reactions respectively. Changes in the composition and quantity of gut microbiota have an important impact on the metabolism of BAs, which can lead to the occurrence of gastrointestinal diseases. BAs, synthesized in the hepatocytes, play an important role in maintaining the homeostasis of gut microbiota and the balance of glucose and lipid metabolism. In consideration of the complex biological functional connections among gut microbiota, BAs, and IBS-D, it is urgent to review the latest research progress in this field. In this review, we summarized the alterations of gut microbiota in IBS-D and discussed the mechanistic connections between gut microbiota and BA metabolism in IBS-D, which may be involved in activating two important bile acid receptors, G-protein coupled bile acid receptor 1 (TGR5) and farnesoid X receptor (FXR). We also highlight the strategies of prevention and treatment of IBS-D via regulating gut microbiota-bile acid axis, including probiotics, fecal microbiota transplantation (FMT), cholestyramine, and the cutting-edge technology about bacteria genetic engineering.

Long-Term Consumption of 2-O-β-d-Glucopyranosyl-l-ascorbic Acid from the Fruits of Lycium barbarum Modulates Gut Microbiota in C57BL/6 Mice

The modulating effect of 2-O-β-d-glucopyranosyl-l-ascorbic acid (AA-2βG), a natural derivative of ascorbic acid from the fruits of Lycium barbarum, on mice gut microbiota was investigated in the present study. It was found that AA-2βG was able to adjust the structure of mice gut microbiota, elevated the relative abundances of Verrucomicrobia, Porphyromonadaceae, Verrucomicrobiaceae, and Erysipelotrichaceae, and meanwhile reduced the relative abundances of Firmicutes, Lachnospiraceae, Rikenellaceae, Ruminococcaceae, Bdellovibrionaceae, Anaeroplasmataceae, and Peptococcaceae. Through the linear discriminant analysis effect size analysis, the key microbiota that were found to be significantly changed after long-term consumption of AA-2βG were Ruminococcaceae, Porphyromonadaceae, Lachnospiraceae, and Rikenellaceae. In addition, AA-2βG could upregulate pro-inflammatory cytokines, promote tight junctions between intestinal cells, facilitate the generation of short-chain fatty acids (SCFAs), and upregulate the mRNA expression level of SCFAs receptors, indicating that AA-2βG might promote organism health. The results demonstrated that AA-2βG might maintain organism health by modulating gut microbiota.

Microbiota-gut-brain axis in health and disease: Is NLRP3 inflammasome at the crossroads of microbiota-gut-brain communications?

Growing evidence highlights the relevance of microbiota-gut-brain axis in the maintenance of brain homeostasis as well as in the pathophysiology of major neurological and psychiatric disorders, including Parkinson's disease (PD), Alzheimer's disease (AD), multiple sclerosis (MS), autism spectrum disorder (ASD) and major depressive disorder (MDD). In particular, changes in gut microbiota can promote enteric and peripheral neurogenic/inflammatory responses, which, in turn, could contribute to neuroinflammation and neurodegeneration in the central nervous system (CNS). Of note, the nucleotide-binding oligomerization domain leucine rich repeat and pyrin domain-containing protein 3 (NLRP3) inflammasome acts as a key player in both coordinating the host physiology and shaping the peripheral and central immune/inflammatory responses in CNS diseases. In this context, there is pioneering evidence supporting the existence of a microbiota-gut-inflammasome-brain axis, in which enteric bacteria modulate, via NLRP3 signaling, inflammatory pathways that, in turn, contribute to influence brain homeostasis. The present review provides an overview of current knowledge on the role of microbiota-gut-inflammasome-brain axis in the major CNS diseases, including PD, AD, MS, ASD and MDD. In particular, though no direct and causal correlation among altered gut microbiota, NLRP3 activation and brain pathology has been demonstrated and in-depth studies are needed in this setting, our purpose was to pave the way to a novel and pioneering perspective on the pathophysiology of CNS disorders. Our intent was also to highlight and discuss whether alterations of microbiota-gut-inflammasome-brain axis support a holistic view of the pathophysiology of CNS diseases, even though each disorder displays a different clinical picture.

Human milk cortisol and immune factors over the first three postnatal months: Relations to maternal psychosocial distress

Background

Many biologically active factors are present in human milk including proteins, lipids, immune factors, and hormones. The milk composition varies over time and shows large inter-individual variability. This study examined variations of human milk immune factors and cortisol concentrations in the first three months post-partum, and their potential associations with maternal psychosocial distress.

Methods

Seventy-seven healthy mothers with full term pregnancies were enrolled, of which 51 mothers collected morning milk samples at 2, 6 and 12 weeks post-delivery. Maternal psychosocial distress was assessed at 6 weeks post-delivery using questionnaires for stress, anxiety, and depressive symptoms. Immune factors were determined using multiplex immunoassays and included innate immunity factors (IL1β, IL6, IL12, IFNγ, TNFα), acquired immunity factors (IL2, IL4, IL10, IL13, IL17), chemokines (IL8, Groα, MCP1, MIP1β), growth factors (IL5, IL7, GCSF, GMCSF, TGFβ2) and immunoglobulins (IgA, total IgG, IgM). Cortisol was quantified using liquid chromatography-tandem mass spectrometry. A linear mixed effects model was fit to test whether stress, anxiety, and depressive symptoms individually predicted human milk cortisol concentrations after accounting for covariates. Repeated measurement analyses were used to compare women with high (n = 13) versus low psychosocial distress (n = 13) for immune factors and cortisol concentrations.

Results

Virtually all immune factors and cortisol, with the exception of the granulocyte-macrophage colony-stimulating factor (GMCSF), were detected in the human milk samples. The concentrations of the immune factors decreased during the first 3 months, while cortisol concentrations increased over time. No correlation was observed between any of the immune factors and cortisol. No consistent relationship between postnatal psychosocial distress and concentrations of immune factors was found, whereas higher psychosocial distress was predictive of higher cortisol concentrations in human milk.

Conclusion

In the current study we found no evidence for an association between natural variations in maternal distress and immune factor concentrations in milk. It is uncertain if this lack of association would also be observed in studies with larger populations, with less uniform demographic characteristics, or with women with higher (clinical) levels of anxiety, stress and/or depressive symptoms. In contrast, maternal psychosocial distress was positively related to higher milk cortisol concentrations at week 2 post-delivery. Further investigation on maternal psychosocial distress in relation to human milk composition is warranted.

Dominant and Subordinate Relationship Formed by Repeated Social Encounters Alters Gut Microbiota in Greater Long-Tailed Hamsters

Social stress can dramatically influence the health of animals via communication between gut microbiota and the HPA system. However, this effect has been rarely investigated among different social ranked animals after chronic repeated social encounters. In this study, we evaluated changes and differences in microbiota among control, dominant, and subordinate male greater long-tailed hamsters (Tscherskia triton) over 28 successive days of repeated social encounter. Our results indicated that as compared with the control group, short-term repeated social encounters significantly altered fecal microbiota of subordinate hamsters, while chronic repeated social encounters altered colonic mucosa-associated microbiota of both dominant and subordinate hamsters. Fecal microbiota showed a transition in composition and diversity on day 2 for the subordinate group but on day 4 for the control and dominant groups under repeated encounters. Compared with their baseline, genus Lactobacillus increased in both dominant and subordinate groups, while genus Bifidobacterium increased in the subordinate group and genus Adlercreutzia increased in the dominant group. Our results suggest that chronic repeated social encounter can alter diversity and composition of gut microbiota of hamsters in both feces and colonic mucosa, but the latter performed better in reflecting the effects of chronic stress on microbiota in this species. Future studies should focus on elucidating how these microbiota alterations may affect animal behavior and fitness.

Analysis of Faecal Zonulin and Calprotectin Concentrations in Healthy Children During the First Two Years of Life. An Observational Prospective Cohort Study

Factors affecting the intestinal-barrier permeability of newborns, such as body mass index (BMI), nutrition and antibiotics, are assumed to affect intestinal-barrier permeability in the first two years of life. This study assessed 100 healthy, full-term newborns to 24 months old. Faecal zonulin/calprotectin concentrations were measured at 1, 6, 12, 24 months as gut-permeability markers. Zonulin concentrations increased between 1 and 12 months (medians: 114.41, 223.7 ng/mL; respectively), whereas calprotectin concentrations decreased between one and six months (medians: 149. 29, 109.28 µg/mL); both then stabilized (24 months: 256.9 ng/mL zonulin; 59.5 µg/mL calprotectin). In individual children, high levels at one month gave high levels at older ages (correlations: calprotectin: between 1 and 6 or 12 months: correlation coefficient (R) = 0.33, statistical significance (p) = 0.0095; R = 0.28, p = 0.032; zonulin: between 1 and 24 months: R = 0.32; p = 0.022, respectively). Parameters which gave marker increases: antibiotics during pregnancy (calprotectin; six months: by 80%, p = 0.038; 12 months: by 48%, p = 0.028); vaginal birth (calprotectin: 6 months: by 140%, p = 0.005); and > 5.7 pregnancy-BMI increase (zonulin: 12 months: by 74%, p = 0.049). Conclusions: “Closure of the intestines” is spread over time and begins between the sixth and twelfth month of life. Antibiotic therapy, BMI increase > 5.7 during pregnancy and vaginal birth are associated with increased intestinal permeability during the first two years of life. Stool zonulin and calprotectin concentrations were much higher compared with previous measurements at older ages; clinical interpretation and validation are needed (no health associations found).

Surface components and metabolites of probiotics for regulation of intestinal epithelial barrier

The gut microbiota can significantly affect the function of the intestinal barrier. Some intestinal probiotics (such as Lactobacillus, Bifidobacteria, a few Escherichia coli strains, and a new generation of probiotics including Bacteroides thetaiotaomicron and Akkermansia muciniphila) can maintain intestinal epithelial homeostasis and promote health. This review first summarizes probiotics' regulation of the intestinal epithelium via their surface compounds. Surface layer proteins, flagella, pili and capsular polysaccharides constitute microbial-associated molecular patterns and specifically bind to pattern recognition receptors, which can regulate signaling pathways to produce cytokines or inhibit apoptosis, thereby attenuating inflammation and enhancing the function of the gut epithelium. The review also explains the effects of metabolites (such as secreted proteins, organic acids, indole, extracellular vesicles and bacteriocins) of probiotics on host receptors and the mechanisms by which these metabolites regulate gut epithelial barrier function. Previous reviews summarized the role of the surface macromolecules or metabolites of gut microbes (including both probiotics and pathogens) in human health. However, these reviews were mostly focused on the interactions between these substances and the intestinal mucosal immune system. In the current review, we only focused on probiotics and discussed the molecular interaction between these bacteria and the gut epithelial barrier.

High-level integration of murine intestinal transcriptomics data highlights the importance of the complement system in mucosal homeostasis

Background

The mammalian intestine is a complex biological system that exhibits functional plasticity in its response to diverse stimuli to maintain homeostasis. To improve our understanding of this plasticity, we performed a high-level data integration of 14 whole-genome transcriptomics datasets from samples of intestinal mouse mucosa. We used the tool Centrality based Pathway Analysis (CePa), along with information from the Reactome database.

Results

The results show an integrated response of the mouse intestinal mucosa to challenges with agents introduced orally that were expected to perturb homeostasis. We observed that a common set of pathways respond to different stimuli, of which the most reactive was the Regulation of Complement Cascade pathway. Altered expression of the Regulation of Complement Cascade pathway was verified in mouse organoids challenged with different stimuli in vitro.

Conclusions

Results of the integrated transcriptomics analysis and data driven experiment suggest an important role of epithelial production of complement and host complement defence factors in the maintenance of homeostasis.

Isolation and Identification of Lactic Acid Bacteria Probiotic Culture Candidates for the Treatment of Salmonella enterica Serovar Enteritidis in Neonatal Turkey Poults

The effect of Lactobacillus spp.-based probiotic candidates on Salmonella enterica serovar Enteritidis (SE) colonization was evaluated in two separate experiments. In each experiment, sixty-one day-of-hatch female turkey poults were obtained from a local hatchery. In both experiments, poults were challenged via oral gavage with 10⁴ cfu/poult of SE and randomly allocated to one of two groups (n = 30 poults): (1) the positive control group and (2) the probiotic treated group. Heated brooder batteries were used for housing each group separately and poults were allowed ad libitum access to water and unmedicated turkey starter feed. 1 h following the SE challenge, poults were treated with 10⁶ cfu/poult of probiotic culture via oral gavage or phosphate-buffered saline （PBS）to control groups. A total of 24 h post-treatment, poults were euthanized and the ceca and cecal tonsils from twenty poults were collected aseptically for SE recovery. In both trials, a significant reduction in the incidence and log₁₀ cfu/g of SE were observed in poults treated with the probiotic when compared with control poults (p ≤ 0.05). The results of the present study suggest that the administration of this lactic acid-producing bacteria (LAB)-based probiotic 1 h after an SE challenge can be useful in reducing the cecal colonization of this pathogen in neonatal poults.

Necrotizing Enterocolitis Pathophysiology: How Microbiome Data Alter Our Understanding

Necrotizing enterocolitis is a major cause of mortality and morbidity in the preterm infant population. The gut microbiome is of particular interest in research surrounding necrotizing enterocolitis, because variations in the intestinal microbiota seem to correlate with the risk of inflammation and disease. Recent advances in non-culture-based genomic sequencing have also allowed for more intricate analyses of the intestinal microbiome. Its evolution seems to be influenced by intrauterine and extrauterine factors, ranging from antenatal antibiotic exposure to type of enteral feeds. Ultimately, these alterations in the gut microbiome have the potential to result in devastating diseases like necrotizing enterocolitis.

Roles of Probiotic Lactobacilli Inclusion in Helping Piglets Establish Healthy Intestinal Inter-environment for Pathogen Defense

The gastrointestinal tract of pigs is densely populated with microorganisms that closely interact with the host and with ingested feed. Gut microbiota benefits the host by providing nutrients from dietary substrates and modulating the development and function of the digestive and immune systems. An optimized gastrointestinal microbiome is crucial for pigs' health, and establishment of the microbiome in piglets is especially important for growth and disease resistance. However, the microbiome in the gastrointestinal tract of piglets is immature and easily influenced by the environment. Supplementing the microbiome of piglets with probiotic bacteria such as Lactobacillus could help create an optimized microbiome by improving the abundance and number of lactobacilli and other indigenous probiotic bacteria. Dominant indigenous probiotic bacteria could improve piglets' growth and immunity through certain cascade signal transduction pathways. The piglet body provides a permissive habitat and nutrients for bacterial colonization and growth. In return, probiotic bacteria produce prebiotics such as short-chain fatty acids and bacteriocins that benefit piglets by enhancing their growth and reducing their risk of enteric infection by pathogens. A comprehensive understanding of the interactions between piglets and members of their gut microbiota will help develop new dietary interventions that can enhance piglets' growth, protect piglets from enteric diseases caused by pathogenic bacteria, and maximize host feed utilization.

Intestinal microbiome and autoimmune liver disease

At present, it has been proved that intestinal microbial-related disorders are involved in the development and progression of multi-organ system diseases. Intestinal microflora is the accumulation of microbial antigens and activated immune cells. Changes in the composition of intestinal microflora (biological disorders) can destroy the systemic immune tolerance of intestinal and symbiotic bacteria. Toll-like receptors in the intestine recognize microbial-related molecular patterns and T helper lymphocyte subpopulations that can cross-react with host antigens (molecular mimics). Activated enterogenous lymphocytes can migrate to lymph nodes, and enterogenous microbial antigens can migrate to extraintestinal sites. Inflammasomes can form in hepatocytes and hepatic stellate cells, which can drive inflammatory, immune-mediated and fibrotic responses. This article reviews and evaluates the role of intestinal microorganisms in the pathogenesis and treatment of autoimmune liver disease.

Interplay among gut microbiota, intestinal mucosal barrier and enteric neuro-immune system: a common path to neurodegenerative diseases?

Neurological diseases, such as Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis (ALS) and multiple sclerosis, are often associated with functional gastrointestinal disorders. These gastrointestinal disturbances may occur at all stages of the neurodegenerative diseases, to such an extent that they are now considered an integral part of their clinical picture. Several lines of evidence support the contention that, in central neurodegenerative diseases, changes in gut microbiota and enteric neuro-immune system alterations could contribute to gastrointesinal dysfunctions as well as initiation and upward spreading of the neurologic disorder. The present review has been intended to provide a comprehensive overview of the available knowledge on the role played by enteric microbiota, mucosal immune system and enteric nervous system, considered as an integrated network, in the pathophysiology of the main neurological diseases known to be associated with intestinal disturbances. In addition, based on current human and pre-clinical evidence, our intent was to critically discuss whether changes in the dynamic interplay between gut microbiota, intestinal epithelial barrier and enteric neuro-immune system are a consequence of the central neurodegeneration or might represent the starting point of the neurodegenerative process. Special attention has been paid also to discuss whether alterations of the enteric bacterial-neuro-immune network could represent a common path driving the onset of the main neurodegenerative diseases, even though each disease displays its own distinct clinical features.