Intestinal Barrier in Human Health and Disease

Gut microbes, diet, and genetics as drivers of metabolic liver disease: a narrative review outlining implications for precision medicine

Metabolic dysfunction-associated steatotic liver disease (MASLD) is rapidly increasing in prevalence, impacting over a third of the global population. The advanced form of MASLD, Metabolic dysfunction-associated steatohepatitis (MASH), is on track to become the number one indication for liver transplant. FDA-approved pharmacological agents are limited for MASH, despite over 400 ongoing clinical trials, with only a single drug (resmetirom) currently on the market. This is likely due to the heterogeneous nature of disease pathophysiology, which involves interactions between highly individualized genetic and environmental factors. To apply precision medicine approaches that overcome interpersonal variability, in-depth insights into interactions between genetics, nutrition, and the gut microbiome are needed, given that each have emerged as dynamic contributors to MASLD and MASH pathogenesis. Here, we discuss the associations and molecular underpinnings of several of these factors individually and outline their interactions in the context of both patient-based studies and preclinical animal model systems. Finally, we highlight gaps in knowledge that will require further investigation to aid in successfully implementing precision medicine to prevent and alleviate MASLD and MASH.

Hyperglycemic environments directly compromise intestinal epithelial barrier function in an organoid model and hyaluronan (∼35 kDa) protects via a layilin dependent mechanism

BACKGROUND

Metabolic syndrome and diabetes in obese individuals are strong risk factors for development of inflammatory bowel disease (IBD) and colorectal cancer. The pathogenic mechanisms of low-grade metabolic inflammation, including chronic hyperglycemic stress, in disrupting gut homeostasis are poorly understood. In this study, we sought to understand the impact of a hyperglycemic environment on intestinal barrier integrity and the protective effects of small molecular weight (35 kDa) hyaluronan on epithelial barrier function.

METHODS

Intestinal organoids derived from mouse colon were grown in normal glucose media (5 mM) or high glucose media (25 mM) to study the impact of hyperglycemic stress on the intestinal barrier. Additionally, organoids were pretreated with 35 kDa hyaluronan (HA35) to investigate the effect of hyaluronan on epithelial barrier under high glucose stress. Immunoblotting as well as confocal imaging was used to understand changes in barrier proteins, quantitative as well as spatial distribution, respectively. Alterations in barrier function were measured using trans-epithelial electrical resistance and fluorescein isothiocyanate flux assays. Untargeted proteomics analysis was performed to elucidate mechanisms by which HA35 exerts a protective effect on the barrier. Intestinal organoids derived from receptor knockout mice specific to various HA receptors were utilized to understand the role of HA receptors in barrier protection under high glucose conditions.

RESULTS

We found that high glucose stress decreased the protein expression as well as spatial distribution of two key barrier proteins, zona occludens-1 (ZO-1) and occludin. HA35 prevented the degradation or loss of ZO-1 and maintained the spatial distribution of both ZO-1 and occludin under hyperglycemic stress. Functionally, we also observed a protective effect of HA35 on the epithelial barrier under high glucose conditions. We found that HA receptor, layilin, was involved in preventing barrier protein loss (ZO-1) as well as maintaining spatial distribution of ZO-1 and occludin. Additionally, proteomics analysis showed that cell death and survival was the primary pathway upregulated in organoids treated with HA35 under high glucose stress. We found that XIAP associated factor 1 (Xaf1) was modulated by HA35 thereby regulating apoptotic cell death in the intestinal organoid system. Finally, we observed that spatial organization of both focal adhesion kinase (FAK) as well as F-actin was mediated by HA35 via layilin.

CONCLUSION

Our results highlight the impact of hyperglycemic stress on the intestinal barrier function. This is of clinical relevance, as impaired barrier function has been observed in individuals with metabolic syndrome. Additionally, we demonstrate barrier protective effects of HA35 through its receptor layilin and modulation of cellular apoptosis under high glucose stress.

Butyrolactone-I from marine fungi alleviates intestinal barrier damage caused by DSS through regulating Lactobacillus johnsonii and its metabolites in the intestine of mice

Butyrolactone-I (BTL-1), a secondary metabolite from the marine fungus Aspergillus terreus, exhibits numerous biological activities. Previous research has indicated that Butyrolactone-I alleviates intestinal epithelial inflammation via the TLR4/NF-κB and MAPK pathways. However, the mechanisms underlying its protection against intestinal barrier damage remain unclear. This study aims to further elucidate these mechanisms. We observed that BTL-1 administration increased the abundance of Lactobacillus johnsonii (LJ) in both in vivo and in vitro experiments, prompting an investigation into the effects of LJ and its metabolites on DSS-induced inflammatory bowel disease (IBD). The results demonstrated that BTL-1 significantly upregulated tight junction (TJ) and adherens junction (AJ) proteins, maintained intestinal barrier integrity, and alleviated DSS-induced IBD in mice. These effects were associated with the proliferation of LJ and its metabolites, such as butyric and propionic acids, and the inhibition of the MAPK signaling pathway in the colon. Interestingly, administering LJ alone produced a protective effect against DSS-induced IBD similar to that observed with BTL-1. Furthermore, butyric acid, a metabolite of LJ, also upregulated TJ/AJ proteins in intestinal epithelial cells through the MAPK signaling pathway. Our findings suggest that BTL-1 regulates intestinal flora, promotes LJ proliferation, protects intestinal barrier integrity, increases the concentrations of butyric and propionic acids, and ultimately inhibits the activation of the MAPK signaling pathway in mice to alleviate IBD. Therefore, BTL-1 could potentially be used as a natural drug to prevent IBD and maintain intestinal flora balance. IMPORTANCE: We explored how butyrolactone-I exerts a preventive effect on IBD through intestinal bacteria (Lactobacillus johnsonii).

Effects of traditional Chinese medicine polysaccharides on chronic diseases by modulating gut microbiota: A review

Intestinal tract is the largest immune system of human body. Gut microbiota (GM) can produce a large number of metabolites, such as short-chain fatty acids and bile acids, which regulate the physiological health of the host and affect the development of disease. In recent years, traditional Chinese medicine (TCM) polysaccharides have attracted extensive attention with multiple biological activities and low toxicity. TCM polysaccharides can promote the growth of intestinal beneficial bacteria and inhibit the growth of harmful bacteria by regulating the structure and function of GM, thus playing a crucial role in preventing or treating chronic diseases such as inflammatory bowel disease (IBD), obesity, type 2 diabetes mellitus (T2DM), liver diseases, cancer, etc. In this paper, the research progress of TCM polysaccharides in the treatment of chronic diseases such as inflammatory bowel disease, obesity, T2DM, liver diseases, cancer, etc. by modulating GM was reviewed. Meanwhile, this review makes an in-depth discussion on the shortcomings of the research of TCM polysaccharides on chronic diseases by modulating GM, and new valuable prospection for the future researches of TCM polysaccharides are proposed, which will provide new ideas for the further study of TCM polysaccharides.

Protective Capacity of Helichrysum italicum Infusion Against Intestinal Barrier Disruption and Translocation of Salmonella Infantis

BACKGROUND

Helichrysum italicum is a Mediterranean plant with well-known anti-inflammatory activity, but our previous whole transcriptome analysis has found that H. italicum infusion (HII) can also affect cytoskeletal rearrangement and tight junctions. The goal of the present study was to determine if HII improves the intestinal barrier (IB) dysfunction and by what mechanism.

METHODS

Caco-2 cells on Transwell inserts were used as a model of IB permeability. Heat-killed (HKB) or live Salmonella Infantis bacteria were used to induce IB integrity disruption upon three different testing conditions: pre-, co-, and post-treatment with 0.2 v/v% HII. Transepithelial electrical resistance values were used as an indicator of monolayer integrity before and after all treatments, and RT-PCR was used to assess the expression of tight junction proteins (TJPs) and inflammatory cytokines known to regulate intestinal permeability.

RESULTS

We found that all three treatments with HII improved the HKB-induced integrity disruption and decreased the down-regulation of TJP1, OCLN, and CLDN1, with the greatest effect observed in the pre-treated cells. Treatment with HII also decreased the up-regulation of CLDN2, TNF-α, IL-1β, and IL-6. In addition, pre-treatment of Caco-2 cells with HII prevented translocation of S. Infantis but did not prevent adhesion and invasion.

CONCLUSION

This study showed that HII can improve inflammation-disrupted IB function by indirect modulation of mRNA expression of TJPs, especially in a preventive manner.

Bioaccumulation Rate of Non-Biodegradable Polystyrene Microplastics in Human Epithelial Cell Lines

Environment plastic accumulation has been attracting the attention of both political and scientific communities, who wish to reduce global pollution. Plastic items have been detected everywhere, from oceans to the air, raising concerns about the fate of plastics within organisms. Leaked plastics are ingested by animals, entering the food chain and eventually reaching humans. Although a lot of studies focused on the evaluation of plastic particles in the environment and living organisms have already been published, the behavior of plastic at the cellular level is still missing. Here, we analyzed the bioaccumulation and extrusion trend of two differently sized plastic particles (1 and 2 µm), testing them on three human epithelial cell lines (liver, lung, and gut) that represent epithelial sites mainly exposed to plastic. A different behavior was detected, and the major plastic uptake was shown by liver cells, where the 1 µm beads accumulated with a dose-dependent profile. Moreover, a 60% reduction in the content of 1 µm particles in cells was evaluated after plastic removal. Finally, the viability and proliferation of the three human cell lines were not significantly affected by both the 1 and 2 µm beads, suggesting that cells might have a defense mechanism against plastic exposure risk.

Macleaya cordata extract improves egg quality by altering gut health and microbiota in laying hens

This study investigated the effect of Macleaya cordata extract (MCE) on the performance, gut health, and microbiota of laying hens. A total of 192 thirty-wk-old Hyline brown laying hens were randomly divided into 4 treatment groups. The CON group received a basal diet, while the low (MCE250), medium (MCE350), and high (MCE450) dose groups were supplemented with 250, 350, and 450 mg/kg MCE, respectively. The egg weight and Haugh unit demonstrated a linear and quadratic increase with the MCE dose during the initial 4-wk period of the experiment (P < 0.05). Furthermore, the dietary supplementation of MCE led to a significant enhancement in eggshell thickness and Haugh unit at wk 8 and the data showed a statistically significant linear and quadratic increase (P < 0.05). Serum cytokine assay showed that dietary supplementation of MCE led to linear and quadratic increases in IL-4 and IL-10 level (P < 0.05). Dietary supplementation of 350 and 450 mg/kg MCE was observed to result in linear and quadratic increase in serum lysozyme levels (P < 0.05). The addition of MCE to the diet resulted in a linear and quadratic increase in the levels of sIgA in the jejunum and ileum (P < 0.05). In terms of gene expression, the addition of MCE to the diet resulted in linear and quadratic increases in the expression of IL-10, IgA, Serpinb14, Serpinb14B, and OIH (P < 0.05). The expression of jejunal genes pIgR and IL-4 was observed to increase in a linear and quadratic manner, respectively, following the dietary addition of 350 mg/kg MCE and IL-1β decreased in a linear manner (P < 0.05). Moreover, these favorable effects were maximized at medium dosage (350 mg/kg) of MCE addition, and intestinal microbial composition in the control and MCE350 groups was assessed. 350 mg/kg MCE increased the relative abundance of Bryobacter and Parasutterella and decreased the relative abundance of Erysipelatoclostridium in the cecum (P < 0.05). Spearman correlation analysis revealed that Bryobacter, Parasutterella, Skermanella, and Erysipelatoclostridium were associated with nonspecific immune functions (P < 0.05). In conclusion, 350 mg/kg MCE supplementation elevated the immune response, and upregulated the expression of genes related to protein production in eggs, thereby improving egg quality. These effects may be associated with changes in the microbiota, specifically Bryobacter, Parasutterella, and Erysipelatoclostridium.

Gut Lactococcus garvieae promotes protective immunity to foodborne Clostridium perfringens infection

The gut microbiota, a pivotal component of the intestinal mucosal barrier, is critical for host resistance to enteric pathogen infection. Here, we report a novel function of the potentially probiotic Lactococcus garvieae strain LG1 (L. garvieae strain LG1) in maintaining intestinal mucosal barrier integrity and protecting against foodborne Clostridium perfringens (C. perfringens) infection. L. garvieae was isolated from the intestinal contents of Chinese Mongolian sheep (MS) and exhibited potential probiotic properties. In a C. perfringens enterocolitis model, L. garvieae-pretreated mice were less susceptible to C. perfringens infection compared with Phosphate buffered solution (PBS)-pretreated mice, which manifested as higher survival rates, lower pathogen loads, less weight loss, mild clinical symptoms and intestinal damage, and minor inflammation. Further mechanistic analysis showed that L. garvieae could ameliorate the disruption of intestinal permeability and maintain the integrity of the intestinal mucosal barrier by promoting the expression of tight junction proteins and mucoproteins. Moreover, L. garvieae was also able to facilitate antimicrobial peptide expression and ameliorate dysbiosis of the gut microbiota caused by C. perfringens. Together, these findings highlight the prospect of immunomodulatory potentially probiotic L. garvieae and might offer valuable strategies for prophylaxis and/or treatment of pathogenic C. perfringens mucosal infection.

IMPORTANCE

C. perfringens necrotic enteritis leads to losses of about US $2 billion to the poultry industry worldwide every year. Worse, US Centers for Disease Control and Prevention (CDC) has estimated that C. perfringens causes nearly 1 million foodborne illnesses in the United States annually. Nowadays, the treatment recommendation is a combination of a broad-spectrum synergistic penicillin with clindamycin or a carbapenem, despite growing scientific concern over antibiotic resistance. The global understanding of the gut microbiome for C. perfringens infection may provide important insights into the intervention. L. garvieae originated from Mongolian sheep intestine, exhibited potentially probiotic properties, and was able to limit C. perfringens enterocolitis and pathogenic colonization. Importantly, we found that L. garvieae limits C. perfringens invasion via improving intestinal mucosal barrier function. Also, L. garvieae alleviates C. perfringens-induced gut microbiota dysbiosis. It allowed us to convince that utilization of probiotics to promote protective immunity against pathogens infection is of pivotal importance.

Gut Distribution, Impact Factor, and Action Mechanism of Bacteriocin-Producing Beneficial Microbes as Promising Antimicrobial Agents in Gastrointestinal Infection

Gastrointestinal (GI) infection by intestinal pathogens poses great threats to human health, and the therapeutic use of antibiotics has reached a bottleneck due to drug resistance. The developments of antimicrobial peptides produced by beneficial bacteria have drawn attention by virtue of effective, safe, and not prone to developing resistance. Though bacteriocin as antimicrobial agent in gut infection has been intensively investigated and reviewed, reviews on that of bacteriocin-producing beneficial microbes are very rare. It is important to explicitly state the prospect of bacteriocin-producing microbes in prevention of gastrointestinal infection towards their application in host. This review discusses the potential of gut as an appropriate resource for mining targeted bacteriocin-producing microbes. Then, host-related factors affecting the bacteriocin production and activity of bacteriocin-producing microbes in the gut are summarized. Accordingly, the multiple mechanisms (direct inhibition and indirect inhibition) behind the preventive effects of bacteriocin-producing microbes on gut infection are discussed. Finally, we propose several targeted strategies for the manipulation of bacteriocin-producing beneficial microbes to improve their performance in antimicrobial outcomes. We anticipate an upcoming emergence of developments and applications of bacteriocin-producing beneficial microbes as antimicrobial agent in gut infection induced by pathogenic bacteria.

The emerging role of the gut microbiota and its application in inflammatory bowel disease

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a complex disorder with an unknown cause. However, the dysbiosis of the gut microbiome has been found to play a role in IBD etiology, including exacerbated immune responses and defective intestinal barrier integrity. The gut microbiome can also be a potential biomarker for several diseases, including IBD. Currently, conventional treatments targeting pro-inflammatory cytokines and pathways in IBD-associated dysbiosis do not yield effective results. Other therapies that directly target the dysbiotic microbiome for effective outcomes are emerging. We review the role of the gut microbiome in health and IBD and its potential as a diagnostic, prognostic, and therapeutic target for IBD. This review also explores emerging therapeutic advancements that target gut microbiome-associated alterations in IBD, such as nanoparticle or encapsulation delivery, fecal microbiota transplantation, nutritional therapies, microbiome/probiotic engineering, phage therapy, mesenchymal stem cells (MSCs), gut proteins, and herbal formulas.

Polygonatum sibiricum polysaccharide regulation of gut microbiota: A viable approach to alleviate cognitive impairment

Polygonatum sibiricum has anti-inflammatory effects and is one of the well-known functional foods. Polygonatum sibiricum polysaccharide (PSP), as a traditional medicinal and food homologous substance, can regulate the balance of intestinal flora and short chain fatty acid levels, reduce intestinal permeability and serum endotoxin levels, and inhibit the activation of astrocytes and microglia. It can significantly alleviate neurological diseases and improve cognitive impairment. Current evidence suggests that bidirectional communication between the central nervous system and the gastrointestinal tract may affect the human nervous system, cognition, and behavior through the gut-brain axis. This article provides a systematic review, detailing the biological activity of PSP, and explores the pathogenesis of gut microbiota signaling in cognitive impairment, providing a promising strategy for improving cognitive impairment.

Intestinal permeability disturbances: causes, diseases and therapy

Nowadays, a pathological increase in the permeability of the intestinal barrier (the so-called leaky gut) is increasingly being diagnosed. This condition can be caused by various factors, mainly from the external environment. Damage to the intestinal barrier entails a number of adverse phenomena: dysbiosis, translocation of microorganisms deep into the intestinal tissue, immune response, development of chronic inflammation. These phenomena can ultimately lead to a vicious cycle that promotes the development of inflammation and further damage to the barrier. Activated immune cells in mucosal tissues with broken barriers can migrate to other organs and negatively affect their functioning. Damaged intestinal barrier can facilitate the development of local diseases such as irritable bowel disease, inflammatory bowel disease or celiac disease, but also the development of systemic inflammatory diseases such as rheumatoid arthritis, ankylosing spondylitis, hepatitis, and lupus erythematosus, neurodegenerative or psychiatric conditions, or metabolic diseases such as diabetes or obesity. However, it must be emphasized that the causal links between a leaky gut barrier and the onset of certain diseases often remain unclear and require in-depth research. In light of recent research, it becomes crucial to prevent damage to the intestinal barrier, as well as to develop therapies for the barrier when it is damaged. This paper presents the current state of knowledge on the causes, health consequences and attempts to treat excessive permeability of the intestinal barrier.

Progress in the study of the correlation between sepsis and intestinal microecology

Sepsis, a disease with high incidence, mortality, and treatment costs, has a complex interaction with the gut microbiota. With advances in high-throughput sequencing technology, the relationship between sepsis and intestinal dysbiosis has become a new research focus. However, owing to the intricate interplay between critical illness and clinical interventions, it is challenging to establish a causal relationship between sepsis and intestinal microbiota imbalance. In this review, the correlation between intestinal microecology and sepsis was summarized, and new therapies for sepsis intervention based on microecological target therapy were proposed, and the shortcomings of bacterial selection and application timing in clinical practice were addressed. In conclusion, current studies on metabolomics, genomics and other aspects aimed at continuously discovering potential probiotics are all providing theoretical basis for restoring intestinal flora homeostasis for subsequent treatment of sepsis.

The gut homeostasis-immune system axis: novel insights into rheumatoid arthritis pathogenesis and treatment

Rheumatoid arthritis is a widely prevalent autoimmune bone disease that imposes a significant burden on global healthcare systems due to its increasing incidence. In recent years, attention has focused on the interaction between gut homeostasis and the immune system, particularly in relation to bone health. Dysbiosis, which refers to an imbalance in the composition and function of the gut microbiota, has been shown to drive immune dysregulation through mechanisms such as the release of pro-inflammatory metabolites, increased gut permeability, and impaired regulatory T cell function. These factors collectively contribute to immune system imbalance, promoting the onset and progression of Rheumatoid arthritis. Dysbiosis induces both local and systemic inflammatory responses, activating key pro-inflammatory cytokines such as tumor necrosis factor-alpha, Interleukin-6, and Interleukin-17, which exacerbate joint inflammation and damage. Investigating the complex interactions between gut homeostasis and immune regulation in the context of Rheumatoid arthritis pathogenesis holds promise for identifying new therapeutic targets, revealing novel mechanisms of disease progression, and offering innovative strategies for clinical treatment.

The Molecular Mechanisms of Portal Vein Thrombosis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) represents the sixth most diagnosed cancer worldwide and is the second leading cause of cancer-related death in the world. The association of HCC and portal vein thrombosis (PVT) represents an advanced stage of the tumor. PVT has a prevalence of about 25-50% in HCC, determining poor prognosis and a remarkable reduction in therapeutic perspectives in these patients, leading to severe complications such as ascites, metastasis, an increase in portal hypertension and potentially fatal gastrointestinal bleeding. The aim of this review is to evaluate the molecular mechanisms that are at the basis of PVT development, trying to evaluate possible strategies in the early detection of patients at high risk of PVT.

Changes in Digestive Health, Satiety and Overall Well-Being after 14 Days of a Multi-Functional GI Primer Supplement

A recent review proposed a role for multi-functional food or supplement products in priming the gut to support both digestive and systemic health. Accordingly, we designed and eva-luated the effect of a multi-functional gastrointestinal (GI) primer supplement on participant-reported measures for digestive health, quality-of-life (e.g., energy/vitality and general health), and reasons for satiation (e.g., attitudes towards food and eating). In this single-arm clinical trial, 68 participants with mild digestive symptoms consumed the GI primer supplement daily for 14 days. Digestive symptoms were evaluated daily from baseline (Day 0) through Day 14. At baseline and Day 14, participants reported their stool consistency, reasons for satiation, and quality-of-life measures using validated questionnaires. At Day 14, participants reported significant improvements in all (13/13) digestive symptom parameters (p-values < 0.05) and an increase in % of stools with normal consistencies. There were significant improvements (p-values < 0.05) in energy/vitality and general health, and in specific attitudes towards food and eating (e.g., physical satisfaction, planned amount, decreased eating priority, decreased food appeal, and self-consciousness). Results suggest the GI primer supplement promotes digestive health, improves quality of life, and impacts attitudes towards food/eating. This study provides preliminary support for the gut priming hypothesis through which multi-functional digestive products may improve GI health.

Probiotic-fermented traditional Chinese herbal medicine, a promising approach to maintaining the intestinal microecology

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese herbal medicines (TCHM) have been extensively used in China and other East and Southeast Asian countries. Due to the low content of bioactive components in most TCHM and the potential toxicity of some herbal ingredients to humans, researchers have turned to probiotic fermentation to enhance the efficacy, mitigate the toxic or side effects and improve the taste of TCHM. Both probiotics and certain TCHM benefit the intestinal microbiota and intestinal barrier of human body, demonstrating synergistic effects on in intestinal microecology.

AIM OF THE STUDY

This review aims to provide an overview of the development of fermentation technology, commonly used probiotic strains for TCHM fermentation, the advantages of probiotic fermentation and the challenges and limitations of probiotic-fermented TCHM. Additionally, it summarises and discusses the impact of probiotic-fermented TCHM on the intestinal barrier and microbiota, as well as the possible mechanisms involved.

MATERIALS AND METHODS

An extensive search of primary literature was conducted using various databases including PubMed, Google Scholar, Web of Science, Elsevier, SpringerLink, ScienceDirect, CNKI, and others. All the plant names have been checked with World Flora Online (http://www.worldfloraonline.org) on August 7, 2024.

RESULTS

The literature mentioned above was analyzed and summarized comprehensively. Probiotic-fermented TCHM can improve the intestinal barrier, modulate gut microbiota, and maintain homeostasis of the intestinal microecology. Modulating intestinal microecology by probiotic-fermented TCHM may be a crucial mechanism for its beneficial effects.

CONCLUSIONS

This article establishes a theoretical basis for further research on the relationship between probiotic-fermented TCHM and the intestinal microecology, with the hope of inspiring innovative concepts for the development of TCHM and exploring the potential of probiotic-fermented TCHM as a promising strategy for maintaining intestinal microecological balance.

The Kynurenine Pathway in Gut Permeability and Inflammation

The gut-brain axis (GBA) is a crucial communication network linking the gastrointestinal (GI) tract and the central nervous system (CNS). The gut microbiota significantly influences metabolic, immune, and neural functions by generating a diverse array of bioactive compounds that modulate brain function and maintain homeostasis. A pivotal mechanism in this communication is the kynurenine pathway, which metabolises tryptophan into various derivatives, including neuroactive and neurotoxic compounds. Alterations in gut microbiota composition can increase gut permeability, triggering inflammation and neuroinflammation, and contributing to neuropsychiatric disorders. This review elucidates the mechanisms by which changes in gut permeability may lead to systemic inflammation and neuroinflammation, with a focus on the kynurenine pathway. We explore how probiotics can modulate the kynurenine pathway and reduce neuroinflammation, highlighting their potential as therapeutic interventions for neuropsychiatric disorders. The review integrates experimental data, discusses the balance between neurotoxic and neuroprotective kynurenine metabolites, and examines the role of probiotics in regulating inflammation, cognitive development, and gut-brain axis functions. The insights provided aim to guide future research and therapeutic strategies for mitigating GI complaints and their neurological consequences.

Effect of Oral Nutritional Supplementation on Health-Related Outcomes and Nutritional Biomarkers in Children and Adolescents with Undernutrition: A Systematic Review and Meta-Analysis

This systematic review aims to synthesize scientific evidence on the effects of oral nutritional supplementation (ONS) on health-related outcomes and nutritional biomarkers among children and adolescents with undernutrition. The review protocol was reported following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) guidelines. A comprehensive keyword and reference search was conducted in seven electronic bibliographic databases: PubMed, Academic Search Complete, Academic Search Premier, CINAHL, Global Health, Web of Science, and Scopus. We identified 14 peer-reviewed articles reporting results from 13 unique studies (eight randomized controlled trials, four pre-post studies, and one observational study). Study participants were recruited from 14 countries/regions, with ages ranging from 1 to 14 years. Outcomes of interest include health-related outcomes (acute diseases and infections) and nutritional biomarkers (e.g., serum iron and zinc). Six of the eight studies examining acute diseases/infections and five of the seven examining nutritional biomarkers reported statistically significant improvement in some, but not all, outcomes. A meta-analysis of three studies found that ONS interventions reduce the incidence of upper respiratory tract infection (URTI) by 39% (95% CI, 0.42-0.91) in children at nutritional risk when compared to dietary counseling (DC) alone. This systematic review suggests that ONS interventions can improve certain health-related outcomes and nutritional biomarkers in undernourished children and adolescents. Specifically, the use of ONS significantly reduces the risk of URTI, highlighting its potential to enhance immune function and break the cycle of undernutrition and infection.

Acupuncture ameliorates atopic dermatitis by modulating gut barrier function in a gut microbiota-dependent manner in mice

OBJECTIVE

Atopic dermatitis (AD) is a chronic inflammatory skin disease that may be linked to changes in the gut microbiome. Acupuncture has been proven to be effective in reducing AD symptoms without serious adverse events, but its underlying mechanism is not completely understood. The purpose of this study was to investigate whether the potential effect of acupuncture on AD is gut microbiota-dependent.

METHODS

AD-like skin lesions were induced by applying MC903 topically to the cheek of the mouse. Acupuncture was done at the Gok-Ji (LI11) acupoints. AD-like symptoms were assessed by lesion scores, scratching behavior, and histopathological changes; intestinal barrier function was measured by fecal output, serum lipopolysaccharide levels, histopathological changes, and mRNA expression of markers involved in intestinal permeability and inflammation. Gut microbiota was profiled using 16S rRNA gene sequencing from fecal samples.

RESULTS

Acupuncture effectively improved chronic itch as well as the AD-like skin lesions with epidermal thickening, and also significantly altered gut microbiota structure as revealed by β-diversity indices and analysis of similarities. These beneficial effects were eliminated by antibiotic depletion of gut microbiota, but were reproduced in gut microbiota-depleted mice that received a fecal microbiota transplant from acupuncture-treated mice. Interestingly, AD mice had intestinal barrier dysfunction as indicated by increased intestinal permeability, atrophy of the mucosal structure (reduced villus height and crypt depth), decreased expression of tight junctions and mucus synthesis genes, and increased expression of inflammatory mediators in the ileum. Acupuncture attenuated these abnormalities, which was gut microbiota-dependent.

CONCLUSION

Acupuncture ameliorates AD-like phenotypes in a gut microbiota-dependent manner and some of these positive benefits are explained by modulation of the intestinal barrier, providing new perspective for non-pharmacological strategies for modulating gut microbiota to prevent and treat AD. Please cite this article as: Yeom M, Ahn S, Hahm DH, Jang SY, Jang SH, Park SY, Jang JH, Park J, Oh JY, Lee IS, Kim K, Kwon SK, Park HJ. Acupuncture ameliorates atopic dermatitis by modulating gut barrier function in a gut microbiota-dependent manner in mice. J Integr Med. 2024; 22(5): 600-613.

Exploring the Effects and Potential Mechanisms of Hesperidin for the Treatment of CPT-11-Induced Diarrhea: Network Pharmacology, Molecular Docking, and Experimental Validation

Chemotherapy-induced diarrhea (CID) is a potentially serious side effect that often occurs during anticancer therapy and is caused by the toxic effects of chemotherapeutic drugs on the gastrointestinal tract, resulting in increased frequency of bowel movements and fluid contents. Among these agents, irinotecan (CPT-11) is most commonly associated with CID. Hesperidin (HPD), a flavonoid glycoside found predominantly in citrus fruits, has anti-oxidation properties and anti-inflammation properties that may benefit CID management. Nevertheless, its potential mechanism is still uncertain. In this study, we firstly evaluated the pharmacodynamics of HPD for the treatment of CID in a mouse model, then used network pharmacology and molecular docking methods to excavate the mechanism of HPD in relieving CID, and finally further proved the predicted mechanism through molecular biology experiments. The results demonstrate that HPD significantly alleviated diarrhea, weight loss, colonic pathological damage, oxidative stress, and inflammation in CID mice. In addition, 74 potential targets for HPD intervention in CID were verified by network pharmacology, with the top 10 key targets being AKT1, CASP3, ALB, EGFR, HSP90AA1, MMP9, ESR1, ANXA5, PPARG, and IGF1. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the PI3K-Akt pathway, FoxO pathway, MAPK pathway, TNF pathway, and Ras pathway were most relevant to the HPD potential treatment of CID genes. The molecular docking results showed that HPD had good binding to seven apoptosis-related targets, including AKT1, ANXA5, CASP3, HSP90AA1, IGF1, MMP9, and PPARG. Moreover, we verified apoptosis by TdT-mediated dUTP nick-end labeling (TUNEL) staining and immunohistochemistry, and the hypothesis about the proteins above was further verified by Western blotting in vivo experiments. Overall, this study elucidates the potential and underlying mechanisms of HPD in alleviating CID.

Influence of Northern Wild Rice on Gut Dysbiosis and Short Chain Fatty Acids: Correlation with Metabolic and Inflammatory Markers in Mice on High Fat Diet

Wild rice (WLD) attenuated hyperglycemia, hyperlipidemia and chronic inflammation in mice receiving a high-fat diet (HFD) versus white rice (WHR), but the underlying mechanism is not well understood. We examined the influence of HFD + WLD on gut microbiota, short chain fatty acids (SCFAs) and the correlation with metabolic or inflammatory markers in mice versus HFD + WHR. C57BL/6J mice received HFD + 26 g weight (wt) % WHR or WLD or 13 g wt% WHR + 13 g wt% WLD (WTWD) for 12 weeks. Plasma levels of glucose, cholesterol and triglycerides, insulin resistance and inflammatory markers after overnight fasting were lower, and the abundances of fecal Lactobacillus gasseri and propionic acid were higher in HFD + WLD-fed mice than in HFD + WHR-fed mice. The anti-inflammatory effects of HFD + WTWD were weaker than HFD + WLD but were greater than those in HFD + WHR-fed mice. Abundances of fecal Lactobacillus gasseri and propionic acid in mice receiving HFD + WLD were higher than those in mice fed with HFD + WHR. The abundances of fecal L. gasseri and propionic acid negatively correlated with metabolic and inflammatory markers. The findings of the present study suggest that WLD attenuated metabolic and inflammatory disorders in mice on HFD. Interactions between WLD components and gut microbiota may upregulate fecal SCFAs, and the latter may be attributed to the benefits of WLD on metabolism and inflammation in mice on HFD.

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

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

Modulation of gut microbiota on intestinal permeability: A novel strategy for treating gastrointestinal related diseases

Accumulating evidence emphasizes the critical reciprocity between gut microbiota and intestinal barrier function in maintaining the gastrointestinal homeostasis. Given the fundamental role caused by intestinal permeability, which has been scrutinized as a measurable potential indicator of perturbed barrier function in clinical researches, it seems not surprising that recent decades have been marked by augmented efforts to determine the interaction between intestinal microbes and permeability of the individual. However, despite the significant progress in characterizing intestinal permeability and the commensal bacteria in the intestine, the mechanisms involved are still far from being thoroughly revealed. In the present review, based on multiomic methods, high-throughput sequencing and molecular biology techniques, the impacts of gut microbiota on intestinal permeability as well as their complex interaction networks are systematically summarized. Furthermore, the diseases related to intestinal permeability and main causes of changes in intestinal permeability are briefly introduced. The purpose of this review is to provide a novel prospection to elucidate the correlation between intestinal microbiota and permeability, and to explore a promising solution for diagnosis and treatment of gastrointestinal related diseases.

Cardiovascular Risk in Patients with Inflammatory Bowel Diseases-The Role of Endothelial Dysfunction

Inflammatory bowel disease (IBD) is associated with an increased risk of cardiovascular disease (CVD). Cardiovascular pathology in people with IBD has not been well studied to date, and a direct link between cardiovascular events and IBD has not been established. The mechanisms underlying this association include the parallel and dynamic interaction of inflammation, modulation of the composition of the gut microbiota, endothelial dysfunction, thrombogenicity, and increased endothelial and epithelial permeability. Endothelial dysfunction is a common aspect of the pathogenesis of IBD and atherosclerotic CVD and can be considered one of the most important factors leading to the development and progression of cardiovascular pathology in patients with IBD. The purpose of this literature review is to describe the mechanisms underlying the development of endothelial dysfunction and disorders of the structure and function of the gut-vascular barrier in the pathogenesis of the cardiovascular manifestation of IBD.

Possible immune mechanisms of gut microbiota and its metabolites in the occurrence and development of immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by increased platelet destruction and impaired production, leading to an elevated bleeding tendency. Recent studies have demonstrated an important link between the gut microbiota and the onset and progression of several immune diseases in humans, emphasizing that gut microbiota-derived metabolites play a non-negligible role in autoimmune diseases. The gut microbiota and its metabolites, such as short-chain fatty acids, oxidized trimethylamine, tryptophan metabolites, secondary bile acids and lipopolysaccharides, can alter intestinal barrier permeability by modulating immune cell differentiation and cytokine secretion, which in turn affects the systemic immune function of the host. It is therefore reasonable to hypothesize that ecological dysregulation of the gut microbiota may be an entirely new factor in the triggering of ITP. This article reviews the potential immune-related mechanisms of the gut microbiota and representative metabolites in ITP, as well as the important influence of leaky gut on the development of ITP, with a view to enriching the theoretical system of ITP-related gut microecology and providing new ideas for the study of ITP.

Hypoxic Functional Regulation Pathways in the GI Tract: Focus on the HIF-1α and Microbiota's Crosstalk

Hypoxia is an essential gastrointestinal (GI) tract phenomenon that influences both physiologic and pathologic states. Hypoxia-inducible factors (HIFs), the primary drivers of cell adaptation to low-oxygen environments, have been identified as critical regulators of gut homeostasis: directly, through the induction of different proteins linked to intestinal barrier stabilization (ie, adherent proteins, tight junctions, mucins, integrins, intestinal trefoil factor, and adenosine); and indirectly, through the regulation of several immune cell types and the modulation of autophagy and inflammatory processes. Furthermore, hypoxia and HIF-related sensing pathways influence the delicate relationship existing between bacteria and mammalian host cells. In turn, gut commensals establish and maintain the physiologic hypoxia of the GI tract and HIF-α expression. Based on this premise, the goals of this review are to (1) highlight hypoxic molecular pathways in the GI tract, both in physiologic and pathophysiologic settings, such as inflammatory bowel disease; and (2) discuss a potential strategy for ameliorating gut-related disorders, by targeting HIF signaling, which can alleviate inflammatory processes, restore autophagy correct mechanisms, and benefit the host-microbiota equilibrium.

Microbiome-metabolomics-based insight into the protective effects of dietary fiber from sweetpotato residues on the high-fat diet-induced intestinal integrity damage

Dietary fibers have attracted much attention due to their multiple benefits on gut health. In this work, the protective mechanism of dietary fiber from sweetpotato residues (SRDF) on the high-fat diet (HFD)-induced intestinal barrier injury was investigated using microbiome-metabolomics-based approach. The physicochemical property analysis demonstrated a thermal stability below 200 °C and porous pectin-polysaccharide structure of SRDF with high in vitro functional activities. The biochemical analysis indicated that SRDF significantly ameliorated intestinal barrier function by improving intestinal morphology and permeability and inhibiting inflammatory response. Microbiome analysis demonstrated that SRDF significantly reversed the HFD-induced dysbacteriosis, decreased the ratio of Firmicutes/Bacteroides and enhanced the relative abundance of probiotics, such as Muribaculaceae and Bifidobacteriaceae. Metabolomics analysis showed that SRDF also significantly altered the metabolic profile in the colon, wherein the differential metabolites were mainly involved in amino acid metabolism (especially tryptophan). Pearson correlation coefficient identified the beneficial relationship between intestinal microbiome and metabolome induced by SRDF. The limitation of this study was that the mouse model may not fully replicate the human intestinal responses due to the difference between the standard environmental conditions and natural world. Generally, our results implied the great potential of SRDF as a functional food ingredient.

Lactoferrin alleviates chronic low‑grade inflammation response in obese mice by regulating intestinal flora

Chronic low‑grade inflammation defines obesity as a metabolic disorder. Alterations in the structure of gut flora are strongly associated with obesity. Lactoferrin (LF) has a biological function in regulating intestinal flora. The present study aimed to investigate the therapeutic and anti‑-inflammatory effects of LF in obese mice based on intestinal flora. A total of 30 C57BL/6 mice were divided into three groups consisting of 10 mice each. Subsequently, one group was fed a normal diet (Group K), another group was fed a high‑fat diet (Group M) and the remaining group switched from regular drinking to drinking 2% LF water (Group Z2) after 2 weeks of high‑fat diet; all mice were fed for 12 weeks. After the experiment, the mouse blood lipid and lipopolysaccharide levels, levels of inflammatory factors and intestinal tight junction proteins were assessed. Mouse stool samples were analyzed using 16S ribosomal RNA sequencing. The results showed that LF reduced serum total cholesterol, triglycerides and low‑density lipoprotein levels, elevated high‑density lipoprotein levels, suppressed metabolic endotoxemia and attenuated chronic low‑grade inflammatory responses in obese mice. In addition, LF upregulated zonula occludens‑1 and occludin protein expression levels in the intestine, thereby improving intestinal barrier integrity. LF altered the intestinal microbial structure of obese mice, reduced the ratio of Firmicutes and an elevated ratio of Bacteroidota, modifying the bacterial population to the increased relative abundance of Alistipes, Acidobacteriota, Psychrobacter and Bryobacter.

Impacts of PFOS, PFOA and their alternatives on the gut, intestinal barriers and gut-organ axis

With the restricted use of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), a number of alternatives to PFOS and PFOA have attracted great interest. Most of the alternatives are still characterized by persistence, bioaccumulation, and a variety of toxicity. Due to the production and use of these substances, they can be detected in the atmosphere, soil and water body. They affect human health through several exposure pathways and especially enter the gut by drinking water and eating food, which results in gut toxicity. In this review, we summarized the effects of PFOS, PFOA and 9 alternatives on pathological changes in the gut, the disruption of physical, chemical, biological and immune barriers of the intestine, and the gut-organ axis. This review provides a valuable understanding of the gut toxicity of PFOS, PFOA and their alternatives as well as the human health risks of emerging contaminants.

Dietary Polycan, a β-glucan originating from Aureobasidium pullulansSM-2001, attenuates high-fat-diet-induced intestinal barrier damage in obese mice by modulating gut microbiota dysbiosis

Various metabolic diseases caused by a high-fat diet (HFD) are closely related to gut microbiota dysbiosis and epithelial barrier dysfunction. Polycan, a type of β-glucan, is effective in treating anti-obesity and metabolic diseases caused by HFD. However, the effect of Polycan on dysbiosis and epithelial barrier damage is still unknown. In this study, the effects of Polycan on dysbiosis and intestinal barrier damage were investigated using HFD-induced obese model mice. C57BL/6 mice were fed a HFD for 12 weeks and treated with two different doses of Polycan (250 and 500 mg/kg) orally administered during weeks 9 to 12. Polycan supplementation increased the expression of tight junction genes (zonula occludens-1, occludin, and claudin-3) and short-chain fatty acid (SCFA) content while reducing toxic substances (phenol, p-cresol, and skatole). Most significantly, Polycan enriched SCFA-producing bacteria (i.e., Phocaeicola, Bacteroides, Faecalibaculum, Oscillibacter, Lachnospiraceae, and Muribaculaceae), and decreased the Firmicutes/Bacteroidetes ratio and toxic substances-producing bacteria (i.e., Olsenella, Clostridium XVIII, and Schaedlerella). Furthermore, microbial functional capacity prediction of the gut microbiota revealed that Polycan enriched many SCFA-related KEGG enzymes while toxic substance-related KEGG enzymes were depleted. These findings indicated that Polycan has the potential to alleviate HFD-induced intestinal barrier damage by modulating the function and composition of the gut microbiota.

The oral-gut microbiome axis in inflammatory bowel disease: from inside to insight

Inflammatory bowel disease (IBD) is an idiopathic and persistent inflammatory illness of the bowels, leading to a substantial burden on both society and patients due to its high incidence and recurrence. The pathogenesis of IBD is multifaceted, partly attributed to the imbalance of immune responses toward the gut microbiota. There is a correlation between the severity of the disease and the imbalance in the oral microbiota, which has been discovered in recent research highlighting the role of oral microbes in the development of IBD. In addition, various oral conditions, such as angular cheilitis and periodontitis, are common extraintestinal manifestations (EIMs) of IBD and are associated with the severity of colonic inflammation. However, it is still unclear exactly how the oral microbiota contributes to the pathogenesis of IBD. This review sheds light on the probable causal involvement of oral microbiota in intestinal inflammation by providing an overview of the evidence, developments, and future directions regarding the relationship between oral microbiota and IBD. Changes in the oral microbiota can serve as markers for IBD, aiding in early diagnosis and predicting disease progression. Promising advances in probiotic-mediated oral microbiome modification and antibiotic-targeted eradication of specific oral pathogens hold potential to prevent IBD recurrence.

Vitis vinifera L. Leaf Extract, a Microbiota Green Ally against Infectious and Inflammatory Skin and Scalp Diseases: An In-Depth Update

The skin microbiota, with its millions of bacteria, fungi, and viruses, plays a key role in balancing the health of the skin and scalp. Its continuous exposure to potentially harmful stressors can lead to abnormalities such as local dysbiosis, altered barrier function, pathobiont overabundance, and infections often sustained by multidrug-resistant bacteria. These factors contribute to skin impairment, deregulation of immune response, and chronic inflammation, with local and systemic consequences. In this scenario, according to the needs of the bio-circular-green economy model, novel harmless strategies, both for regulating the diverse epidermal infectious and inflammatory processes and for preserving or restoring the host skin eubiosis and barrier selectivity, are requested. Vitis vinifera L. leaves and their derived extracts are rich in plant secondary metabolites, such as polyphenols, with antioxidant, anti-inflammatory, antimicrobial, and immunomodulatory properties that can be further exploited through microbe-driven fermentation processes. On this premise, this literature review aims to provide an informative summary of the most updated evidence on their interactions with skin commensals and pathogens and on their ability to manage inflammatory conditions and restore microbial biodiversity. The emerging research showcases the potential novel beneficial ingredients for addressing various skincare concerns and advancing the cosmeceutics field as well.

Protective properties of Ophiopogonin D in DSS-induced colitis: insights into microbiota modulation

BACKGROUND

Ulcerative colitis (UC), a chronic inflammatory gastrointestinal disorder, is becoming increasingly prevalent worldwide. Ophiopogonin D, which is derived from Ophiopogon japonicus, exhibits anti-inflammatory and antioxidant properties, yet its therapeutic potential in UC remains unclear.

METHODS

In this study, we employed a mouse model of DSS-induced colitis to assess the impact of Ophiopogonin D on various parameters, including weight loss, bloody stools, and inflammation in the colon.

RESULTS

Ophiopogonin-D treatment significantly mitigated these DSS-induced effects, improved colon permeability, and modulated inflammatory markers like ZO-1, MUC-2, TNF-α, and IL-1β in mice compared with the control. Furthermore, compared to the DSS-treatment group, Ophiopogonin-D treatment improved the α- and β-diversity indices of the mouse intestinal microbiota, along with an increase in the abundance of genera such as Akkermansia (AKK) and a decrease in the abundance of genera such as Enterobacter. Notably, propionic acid, a metabolite of AKK, demonstrated significant improvement in the symptoms of DSS-induced colitis in mice compared to the control. Moreover, propionic-acid administration also resulted in alterations in the levels of inflammatory factors and calreticulin within the intestinal tissues.

CONCLUSION

Overall, Ophiopogonin D significantly affects intestinal microbiota composition, thereby improving symptoms of DSS-induced colitis in mice. These findings present promising therapeutic strategies and potential pharmaceutical candidates for the treatment of ulcerative colitis.

Focal Adhesion Kinase and Colony Stimulating Factors: Intestinal Homeostasis and Innate Immunity Crosstalk

Thousands struggle with acute and chronic intestinal injury due to various causes. Epithelial intestinal healing is dependent on phenotypic transitions to a mobile phenotype. Focal adhesion kinase (FAK) is a ubiquitous protein that is essential for cell mobility. This phenotype change is mediated by FAK activation and proves to be a promising target for pharmaceutical intervention. While FAK is crucial for intestinal healing, new evidence connects FAK with innate immunity and the importance it plays in macrophage/monocyte chemotaxis, as well as other intracellular signaling cascades. These cascades play a part in macrophage/monocyte polarization, maturation, and inflammation that is associated with intestinal injury. Colony stimulating factors (CSFs) such as macrophage colony stimulating factor (M-CSF/CSF-1) and granulocyte macrophage colony stimulating factor (GM-CSF/CSF-2) play a critical role in maintaining homeostasis within intestinal mucosa by crosstalk capabilities between macrophages and epithelial cells. The communication between these cells is imperative in orchestrating healing upon injury. Diving deeper into these connections may allow us a greater insight into the role that our immune system plays in healing, as well as a better comprehension of inflammatory diseases of the gut.

Escherichia coli Activate Extraintestinal Antibody Response and Provide Anti-Infective Immunity

The effects of intestinal microflora on extraintestinal immune response by intestinal cytokines and metabolites have been documented, but whether intestinal microbes stimulate serum antibody generation is unknown. Here, serum antibodies against 69 outer membrane proteins of Escherichia coli, a dominant bacterium in the human intestine, are detected in 141 healthy individuals of varying ages. Antibodies against E. coli outer membrane proteins are determined in all serum samples tested, and frequencies of antibodies to five outer membrane proteins (OmpA, OmpX, TsX, HlpA, and FepA) are close to 100%. Serum antibodies against E. coli outer membrane proteins are further validated by Western blot and bacterial pull-down. Moreover, the present study shows that OstA, HlpA, Tsx, NlpB, OmpC, YfcU, and OmpA provide specific immune protection against pathogenic E. coli, while HlpA and OmpA also exhibit cross-protection against Staphylococcus aureus infection. These finding indicate that intestinal E. coli activate extraintestinal antibody responses and provide anti-infective immunity.

Understanding how pre- and probiotics affect the gut microbiome and metabolic health

The gut microbiome, a complex assembly of microorganisms, significantly impacts human health by influencing nutrient absorption, the immune system, and disease response. These microorganisms form a dynamic ecosystem that is critical to maintaining overall well-being. Prebiotics and probiotics are pivotal in regulating gut microbiota composition. Prebiotics nourish beneficial bacteria and promote their growth, whereas probiotics help maintain balance within the microbiome. This intricate balance extends to several aspects of health, including maintaining the integrity of the gut barrier, regulating immune responses, and producing metabolites crucial for metabolic health. Dysbiosis, or an imbalance in the gut microbiota, has been linked to metabolic disorders such as type 2 diabetes, obesity, and cardiovascular disease. Impaired gut barrier function, endotoxemia, and low-grade inflammation are associated with toll-like receptors influencing proinflammatory pathways. Short-chain fatty acids derived from microbial fermentation modulate anti-inflammatory and immune system pathways. Prebiotics positively influence gut microbiota, whereas probiotics, especially Lactobacillus and Bifidobacterium strains, may improve metabolic outcomes, such as glycemic control in diabetes. It is important to consider strain-specific effects and study variability when interpreting these findings, highlighting the need for further research to optimize their therapeutic potential. The aim of this report is therefore to review the role of the gut microbiota in metabolic health and disease and the effects of prebiotics and probiotics on the gut microbiome and their therapeutic role, integrating a broad understanding of physiological mechanisms with a clinical perspective.

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

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

Current Research on the Role of Isomaltooligosaccharides in Gastrointestinal Health and Metabolic Diseases

The intestinal epithelium plays an important role in maintaining the intestinal barrier and facilitating nutrient absorption. It also serves as a critical physical barrier against the infiltration of foreign substances from the intestinal lumen into the circulation. Intestinal barrier dysfunction has been implicated in the development of several diseases. Isomaltooligosaccharides (IMOs), which are a type of dietary fiber, possess multiple health benefits. However, there is limited information regarding their efficacy against gastrointestinal diseases. This review explores the therapeutic potential of IMOs in obesity, diabetes mellitus, inflammatory bowel disease (IBD), hyperlipidemia, and constipation. High-fat diet (HFD)-induced obesity models have shown that IMOs, administered alone or in combination with other compounds, exhibit potent antiobesity effects, making them promising agents in the treatment of obesity and its associated complications. Moreover, IMOs exhibit preventive effects against HFD-induced metabolic dysfunction by modulating gut microbiota and short-chain fatty acid levels, thereby ameliorating symptoms. Furthermore, IMOs can reduce IBD and alleviate hyperlipidemia, as indicated by the reduced histological colitis scores and improved lipid profiles observed in clinical trials and animal studies. This review highlights IMOs as a versatile intervention strategy that can improve gastrointestinal health by modulating gut microbiota, immune responses, and metabolic parameters, providing a multifaceted approach to address the complex nature of gastrointestinal disorders.

Inflammatory Response in the Pathogenesis and Treatment of Hepatocellular Carcinoma: A Double-Edged Weapon

Hepatocellular carcinoma (HCC) is the most frequent among primary liver tumors (90%) and one of the main causes of cancer-related death. It develops usually in a chronically inflamed environment, ranging from compensatory parenchymal regeneration to fibrosis and cirrhosis: carcinogenesis can potentially happen in each of these stages. Inflammation determined by chronic viral infection (hepatitis B, hepatitis C, and hepatitis delta viruses) represents an important risk factor for HCC etiology through both viral direct damage and immune-related mechanisms. The deregulation of the physiological liver immunological network determined by viral infection can lead to carcinogenesis. The recent introduction of immunotherapy as the gold-standard first-line treatment for HCC highlights the role of the immune system and inflammation as a double-edged weapon in both HCC carcinogenesis and treatment. In this review we highlight how the inflammation is the key for the hepatocarcinogenesis in viral, alcohol and metabolic liver diseases.

Intestinal toxicity of Pb: Structural and functional damages, effects on distal organs and preventive strategies

Lead (Pb) is one of the most common heavy metal pollutants that possesses multi-organ toxicity. For decades, great efforts have been devoted to investigate the damage of Pb to kidney, liver, bone, blood cells and the central nervous system (CNS). For the common, dietary exposure is the main avenue of Pb, but our knowledge of Pb toxicity in gastrointestinal tract (GIT) remains quite insufficient. Importantly, emerging evidence has documented that gastrointestinal disorders affect other distal organs like brain and liver though gut-brain axis or gut-liver axis, respectively. This review focuses on the recent understanding of intestinal toxicity of Pb exposure, including structural and functional damages. We also review the influence and mechanism of intestinal toxicity on other distal organs, mainly concentrated on brain and liver. At last, we summarize the bioactive substances that reported to alleviate Pb toxicity, providing potential dietary intervention strategies to prevent or attenuate Pb toxicity.

The role of the gut microbiome in disorders of gut-brain interaction

Disorders of Gut-Brain Interaction (DGBI) are widely prevalent and commonly encountered in gastroenterology practice. While several peripheral and central mechanisms have been implicated in the pathogenesis of DGBI, a recent body of work suggests an important role for the gut microbiome. In this review, we highlight how gut microbiota and their metabolites affect physiologic changes underlying symptoms in DGBI, with a particular focus on their mechanistic influence on GI transit, visceral sensitivity, intestinal barrier function and secretion, and CNS processing. This review emphasizes the complexity of local and distant effects of microbial metabolites on physiological function, influenced by factors such as metabolite concentration, duration of metabolite exposure, receptor location, host genetics, and underlying disease state. Large-scale in vitro work has elucidated interactions between host receptors and the microbial metabolome but there is a need for future research to integrate such preclinical findings with clinical studies. The development of novel, targeted therapeutic strategies for DGBI hinges on a deeper understanding of these metabolite-host interactions, offering exciting possibilities for the future of treatment of DGBI.

Inhibiting the CB1 receptor in CIH-induced animal model alleviates colon injury

Obstructive sleep apnea (OSA) can lead to intestinal injury, endotoxemia, and disturbance of intestinal flora. Additionally, as a crucial component of the endocannabinoid system, some studies have demonstrated that cannabinoid 1 (CB1) receptors are closely linked to the multiple organ dysfunction triggered by OSA. However, the role of the CB1 receptor in alleviating OSA-induced colon injury remains unclear. Here, through the construction of the OSA classic model, we found that the colon tissue of chronic intermittent hypoxia (CIH)-induced mice exhibited an overexpression of the CB1 receptor. The results of hematoxylin-eosin staining and transmission electron microscopy revealed that inhibition of the CB1 receptor could decrease the gap between the mucosa and muscularis mucosae, alleviate mitochondrial swelling, reduce microvilli shedding, and promote the recovery of tight junctions of CIH-induced mice. Furthermore, CB1 receptor inhibition reduced the levels of metabolic endotoxemia and inflammatory responses, exhibiting significant protective effects on the colon injury caused by CIH. At the molecular level, through western blotting and real-time polymerase chain reaction techniques, we found that inhibiting the CB1 receptor can significantly increase the expression of ZO-1 and Occludin proteins, which are closely related to the maintenance of intestinal mucosal barrier function. Through 16S rRNA high-throughput sequencing and short-chain fatty acid (SCFA) determination, we found that inhibition of the CB1 receptor increased the diversity of the microbial flora and controlled the makeup of intestinal flora. Moreover, butyric acid concentration and the amount of SCFA-producing bacteria, such as Ruminococcaceae and Lachnospiraceae, were both markedly elevated by CB1 receptor inhibition. The results of the spearman correlation study indicated that Lachnospiraceae showed a positive association with both ZO-1 and Occludin but was negatively correlated with the colon CB1 receptor, IL-1β, and TNF-α. According to this study, we found that inhibiting CB1 receptor can improve CIH-induced colon injury by regulating gut microbiota, reducing mucosal damage and promoting tight junction recovery. KEY POINTS: •CIH leads to overexpression of CB1 receptor in colon tissue. •CIH causes intestinal flora disorder, intestinal mucosal damage, and disruption of tight junctions. •Inhibition of CB1 receptor can alleviate the colon injury caused by CIH through regulating the gut microbiota, reducing mucosal injury, and promoting tight junction recovery.

Effect of micro- and nanoplastic particles on human macrophages

Micro- and nanoplastics (MNPs) are ubiquitous in the environment, resulting in the uptake of MNPs by a variety of organisms, including humans, leading to particle-cell interaction. Human macrophages derived from THP-1 cell lines take up Polystyrene (PS), a widespread plastic. The question therefore arises whether primary human macrophages also take up PS micro- and nanobeads (MNBs) and how they react to this stimulation. Major aim of this study is to visualize this uptake and to validate the isolation of macrophages from peripheral blood mononuclear cells (PBMCs) to assess the impact of MNPs on human macrophages. Uptake of macrophages from THP-1 cell lines and PBMCs was examined by transmission electron microscopy (TEM), scanning electron microscopy and live cell imaging. In addition, the reaction of the macrophages was analyzed in terms of metabolic activity, cytotoxicity, production of reactive oxygen species (ROS) and macrophage polarization. This study is the first to visualize PS MNBs in primary human cells using TEM and live cell imaging. Metabolic activity was size- and concentration-dependent, necrosis and ROS were increased. The methods demonstrated in this study outline an approach to assess the influence of MNP exposure on human macrophages and help investigating the consequences of worldwide plastic pollution.

Mechanisms of epigallocatechin gallate (EGCG) in ameliorating hyperuricemia: insights into gut microbiota and intestinal function in a mouse model

Epigallocatechin gallate (EGCG), a prominent bioactive compound found in tea, offers numerous health benefits. Previous studies have highlighted its potential in mitigating hyperuricemia. In this study, hyperuricemic mice induced by potassium oxonate (PO) were treated with EGCG or the anti-hyperuricemia medication allopurinol (AP) to investigate the mechanisms underlying their anti-hyperuricemic effects. The results demonstrated that both EGCG and AP significantly reduced serum uric acid (UA) levels. Further analysis revealed that EGCG promoted the expression of UA secretion transporter genes (Oat1 and Oct1) while inhibiting the expression of UA reabsorption transporter genes (Urat1 and Glut9) in the kidney. By 16S rDNA sequencing, EGCG, but not AP, was found to alter the composition of the gut microbiota. Notably, EGCG induced significant changes in the relative abundance of specific bacteria such as Lactobacillus, Faecalibaculum, and Bifidobacterium, which displayed high correlations with serum UA levels and UA-related gene expression. Metabolomic analysis suggested that EGCG-induced modifications in bacterial metabolites might contribute to the alleviation of hyperuricemia. Transcriptomic analysis of the intestinal epithelium identifies 191 differentially expressed genes (DEGs) in EGCG-treated mice, including 8 purine-related genes. This study elucidates the anti-hyperuricemic mechanisms of EGCG, particularly its influence on the gut microbiota and gene expression in the intestinal epithelium.

Octreotide attenuates intestinal barrier damage by maintaining basal autophagy in Caco2 cells

The intestinal mucosal barrier is of great importance for maintaining the stability of the internal environment, which is closely related to the occurrence and development of intestinal inflammation. Octreotide (OCT) has potential applicable clinical value for treating intestinal injury according to previous studies, but the underlying molecular mechanisms have remained elusive. This article is based on a cell model of inflammation induced by lipopolysaccharide (LPS), aiming to explore the effects of OCT in protecting intestinal mucosal barrier function. A Cell Counting Kit‑8 assay was used to determine cell viability and evaluate the effectiveness of OCT. Gene silencing technology was used to reveal the mediated effect of somatostatin receptor 2 (SSTR2). The changes in intestinal permeability were detected through trans‑epithelial electrical resistance and fluorescein isothiocyanate‑dextran 4 experiments, and the alterations in tight junction proteins were detected using immunoblotting and reverse transcription fluorescence‑quantitative PCR technology. Autophagosomes were observed by electron microscopy and the dynamic changes of the autophagy process were characterized by light chain (LC)3‑II/LC3‑I conversion and autophagic flow. The results indicated that SSTR2‑dependent OCT can prevent the decrease in cell activity. After LPS treatment, the permeability of monolayer cells decreased and intercellular tight junctions were disrupted, resulting in a decrease in tight junction protein zona occludens 1 in cells. The level of autophagy‑related protein LC3 was altered to varying degrees at different times. These abnormal changes gradually returned to normal levels after the combined application of LPS and SSTR2‑dependent OCT, confirming the role of OCT in protecting intestinal barrier function. These experimental results suggest that OCT maintains basal autophagy and cell activity mediated by SSTR2 in intestinal epithelial cells, thereby preventing the intestinal barrier dysfunction in inflammation injury.

Obeticholic acid attenuates the intestinal barrier disruption in a rat model of short bowel syndrome

BACKGROUND

Short bowel syndrome (SBS) features nutrients malabsorption and impaired intestinal barrier. Patients with SBS are prone to sepsis, intestinal flora dysbiosis and intestinal failure associated liver disease. Protecting intestinal barrier and preventing complications are potential strategies for SBS treatment. This study aims to investigate the effects of farnesoid X receptor (FXR) agonist, obeticholic acid (OCA), have on intestinal barrier and ecological environment in SBS.

METHODS AND RESULTS

Through testing the small intestine and serum samples of patients with SBS, impaired intestinal barrier was verified, as evidenced by reduced expressions of intestinal tight junction proteins (TJPs), increased levels of apoptosis and epithelial cell damage. The intestinal expressions of FXR and related downstream molecules were decreased in SBS patients. Then, global FXR activator OCA was used to further dissect the potential role of the FXR in a rat model of SBS. Low expressions of FXR-related molecules were observed on the small intestine of SBS rats, along with increased proinflammatory factors and damaged barrier function. Furthermore, SBS rats possessed significantly decreased body weight and elevated death rate. Supplementation with OCA mitigated the damaged intestinal barrier and increased proinflammatory factors in SBS rats, accompanied by activated FXR-related molecules. Using 16S rDNA sequencing, the regulatory role of OCA on gut microbiota in SBS rats was witnessed. LPS stimulation to Caco-2 cells induced apoptosis and overexpression of proinflammatory factors in vitro. OCA incubation of LPS-pretreated Caco-2 cells activated FXR-related molecules, increased the expressions of TJPs, ameliorated apoptosis and inhibited overexpression of proinflammatory factors.

CONCLUSIONS

OCA supplementation could effectively ameliorate the intestinal barrier disruption and inhibit overexpression of proinflammatory factors in a rat model of SBS and LPS-pretreated Caco-2 cells. As a selective activator of FXR, OCA might realize its protective function through FXR activation.

Applied physiology: gut microbiota and antimicrobial therapy

The gut microbiota plays an important role in maintaining human health and in the pathogenesis of several diseases. Antibiotics are among the most commonly prescribed drugs and have a significant impact on the structure and function of the gut microbiota. The understanding that a healthy gut microbiota prevents the development of many diseases has also led to its consideration as a potential therapeutic target. At the same time, any factor that alters the gut microbiota becomes important in this approach. Exercise and antibacterial therapy have a direct effect on the microbiota. The review reflects the current state of publications on the mechanisms of intestinal bacterial involvement in the pathogenesis of cardiovascular, metabolic, and neurodegenerative diseases. The physiological mechanisms of the influence of physical activity on the composition of the gut microbiota are considered. The mechanisms of the common interface between exercise and antibacterial therapy will be considered using the example of several socially important diseases. The aim of the study is to show the physiological relationship between the effects of exercise and antibiotics on the gut microbiota.

An overview on the cellular mechanisms of anthocyanins in maintaining intestinal integrity and function

Structural and functional changes of the intestinal barrier, as a consequence of a number of (epi)genetic and environmental causes, have a main role in penetrations of pathogens and toxic agents, and lead to the development of inflammation-related pathological conditions, not only at the level of the GI tract but also in other extra-digestive tissues and organs. Anthocyanins (ACNs), a subclass of polyphenols belonging to the flavonoid group, are well known for their health-promoting properties and are widely distributed in the human diet. There is large evidence about the correlation between the human intake of ACN-rich products and a reduction of intestinal inflammation and dysfunction. Our review describes the more recent advances in the knowledge of cellular and molecular mechanisms through which ACNs can modulate the main mechanisms involved in intestinal dysfunction and inflammation, in particular the inhibition of the NF-κB, JNK, MAPK, STAT3, and TLR4 proinflammatory pathways, the upregulation of the Nrf2 transcription factor and the expression of tight junction proteins and mucins.

Unveiling the dynamics of gut microbial interactions: a review of dietary impact and precision nutrition in gastrointestinal health

The human microbiome, a dynamic ecosystem within the gastrointestinal tract, plays a pivotal role in shaping overall health. This review delves into six interconnected sections, unraveling the intricate relationship between diet, gut microbiota, and their profound impact on human health. The dance of nutrients in the gut orchestrates a complex symphony, influencing digestive processes and susceptibility to gastrointestinal disorders. Emphasizing the bidirectional communication between the gut and the brain, the Brain-Gut Axis section highlights the crucial role of dietary choices in physical, mental, and emotional well-being. Autoimmune diseases, particularly those manifesting in the gastrointestinal tract, reveal the delicate balance disrupted by gut microbiome imbalances. Strategies for reconciling gut microbes through diets, precision nutrition, and clinical indications showcase promising avenues for managing gastrointestinal distress and revolutionizing healthcare. From the Low-FODMAP diet to neuro-gut interventions, these strategies provide a holistic understanding of the gut's dynamic world. Precision nutrition, as a groundbreaking discipline, holds transformative potential by tailoring dietary recommendations to individual gut microbiota compositions, reshaping the landscape of gastrointestinal health. Recent advancements in clinical indications, including exact probiotics, fecal microbiota transplantation, and neuro-gut interventions, signify a new era where the gut microbiome actively participates in therapeutic strategies. As the microbiome takes center stage in healthcare, a paradigm shift toward personalized and effective treatments for gastrointestinal disorders emerges, reflecting the symbiotic relationship between the human body and its microbial companions.