Gut microbiota-derived metabolites in the regulation of host immune responses and immune-related inflammatory diseases

Microbial succinate promotes the response to metformin by upregulating secretory immunoglobulin a in intestinal immunity

Metformin is the first-line pharmacotherapy for type 2 diabetes mellitus; however, many patients respond poorly to this drug in clinical practice. The potential involvement of microbiota-mediated intestinal immunity and related signals in metformin responsiveness has not been previously investigated. In this study, we successfully constructed a humanized mouse model by fecal transplantation of the gut microbiota from clinical metformin-treated - responders and non-responders, and reproduced the difference in clinical phenotypes of responsiveness to metformin. The abundance of Bacteroides thetaiotaomicron, considered a representative differential bacterium of metformin responsiveness, and the level of secretory immunoglobulin A (SIgA) in intestinal immunity increased significantly in responder recipient mice following metformin treatment. In contrast, no significant alterations in B. thetaiotaomicron and SIgA were observed in non-responder recipient mice. The study of IgA-/- mice confirmed that downregulated expression or deficiency of SIgA resulted in non-response to metformin, meaning that metformin was unable to improve dysfunctional glucose metabolism and reduce intestinal and adipose tissue inflammation, ultimately leading to systemic insulin resistance. Furthermore, supplementation with succinate, a microbial product of B. thetaiotaomicron, potentially reversed the non-response to metformin by inducing the production of SIgA. In conclusion, we demonstrated that upregulated SIgA, which could be regulated by succinate, was functionally involved in metformin response through its influence on immune cell-mediated inflammation and insulin resistance. Conversely, an inability to regulate SIgA may result in a lack of response to metformin.

Mouse strain-specific responses along the gut-brain axis upon fecal microbiota transplantation from children with autism

Several factors are linked to the pathophysiology of autism spectrum disorders (ASD); however, the molecular mechanisms of the condition remain unknown. As intestinal problems and gut microbiota dysbiosis are associated with ASD development and severity, recent studies have focused on elucidating the microbiota-gut-brain axis' involvement. This study aims to explore mechanisms through which gut microbiota might influence ASD. Briefly, we depleted the microbiota of conventional male BALB/cAnNCrl (Balb/c) and C57BL/6J (BL/6) mice prior to human fecal microbiota transplantation (hFMT) with samples from children with ASD or their neurotypical siblings. We found mouse strain-specific responses to ASD hFMT. Notably, Balb/c mice exhibit decreased exploratory and social behavior, and show evidence of intestinal, systemic, and central inflammation accompanied with metabolic shifts. BL/6 mice show less changes after hFMT. Our results reveal that gut microbiota alone induce changes in ASD-like behavior, and highlight the importance of mouse strain selection when investigating multifactorial conditions like ASD.

Microbial diversity and fitness in the gut-brain axis: influences on developmental risk for Alzheimer's disease

The gut-brain axis (GBA) denotes the dynamic and bidirectional communication system that connects the gastrointestinal tract and the central nervous system (CNS). This review explored this axis, focusing on the role of microbial diversity and fitness in maintaining gastrointestinal health and preventing neurodegeneration, particularly in Alzheimer's disease (AD). Gut dysbiosis, characterized by the imbalance in populations of beneficial and harmful bacteria, has been associated with increased systemic inflammation, neuroinflammation, and the progression of AD through pathogenic mechanisms involving amyloid deposition, tauopathy, and increased blood-brain barrier (BBB) permeability. Emerging evidence highlighted the therapeutic potential of probiotics, dietary interventions, and intermittent fasting in restoring microbial balance, reducing inflammation, and minimizing neurodegenerative risks. Probiotics and synbiotics are promising in helping improve cognitive function and metabolic health, while dietary patterns like the Mediterranean diet were linked to decreased neuroinflammation and enhanced gut-brain communication. Despite significant advancement, further research is needed to elucidate the specific microbial strains, metabolites, and mechanisms influencing brain health. Future studies employing longitudinal designs and advanced omics technologies are essential to developing targeted microbiome-based therapies for managing AD-related disorders.

Inflammatory bowel disease and neuropsychiatric disorders: Mechanisms and emerging therapeutics targeting the microbiota-gut-brain axis

Crohn's disease (CD) and ulcerative colitis (UC) are the two major entities of inflammatory bowel disease (IBD). These disorders are known for their relapsing disease course and severe gastrointestinal symptoms including pain, diarrhoea and bloody stool. Accumulating evidence suggests that IBD is not only restricted to the gastrointestinal tract and that disease processes are able to reach distant organs including the brain. In fact, up to 35 % of IBD patients also suffer from neuropsychiatric disorders such as generalized anxiety disorder and major depressive disorder. Emerging research in this area indicates that in many cases these neuropsychiatric disorders are a secondary condition as a consequence of the disturbed communication between the gut and the brain via the microbiota-gut-brain axis. In this review, we summarise the current knowledge on IBD-associated neuropsychiatric disorders. We examine the role of different pathways of the microbiota-gut-brain axis in the development of CNS disorders highlighting altered neural, immunological, humoral and microbial communication. Finally, we discuss emerging therapies targeting the microbiota-gut-brain axis to alleviate IBD and neuropsychiatric symptoms including faecal microbiota transplantation, psychobiotics, microbial metabolites and vagus nerve stimulation.

Identification of potential shared gene signatures between periodontitis and breast cancer by integrating bulk RNA-seq and scRNA-seq data

Studies have shown that patients with periodontitis (PD) have an increased risk of breast cancer (BC). However, the exact mechanism remains to be further investigated. This study aimed to investigate the genes, pathways and immune cells that may interact with PD and BC. From the Gene Expression Omnibus (GEO) and TCGA databases, we retrieved the gene expression profiles of samples with PD and BC, respectively. Common genes between two diseases were found using differential expression analysis and weighted gene co-expression network analysis (WGCNA). Machine learning methods were used to find shared diagnostic genes. Single-sample GSEA (ssGSEA) was performed to study the expression profiles of 28 immune cells in PD and BC, and single-cell RNA sequencing (scRNA-seq) data was used to visualize localization of shared genes. Finally, we employed qRT-PCR and immunohistochemistry staining to confirm the expression of hub genes in two diseases. PD and BC had 21 shared crosstalk genes, which were primarily related to peptide hormone response, organic acid transmembrane transport, and carboxylic acid transmembrane transport. By using machine learning methods, ANKRD29 and TDO2 were the most efficient shared diagnostic biomarkers, which were confirmed by Immunohistochemical staining and qRT-PCR. ssGSEA showed that immunology was involved in both diseases and that ANKRD29 and TDO2 may be involved in both diseases by mediating immune cells. scRNA-seq further confirms the importance of these genes in regulating immunity in both diseases. In brief, our study identified 2 genes that may serve as biomarkers and targets for the diagnosis and treatment of PD and BC.

Targeting the gut microbiota-inflammation-brain axis as a potential therapeutic strategy for psychiatric disorders: A Mendelian randomization analysis

BACKGROUND

Extensive research indicates a link between gut microbiota dysbiosis and psychiatric disorders. However, the causal relationships between gut microbiota and different types of psychiatric disorders, as well as whether inflammatory factors mediate these relationships, remain unclear.

METHODS

We utilized summary statistics from the largest genome-wide association studies to date for gut microbiota (n = 18,340 in MiBioGen consortium), circulating inflammatory factors (n = 8293 for 41 factors and n = 14,824 for 91 factors in GWAS catalog), and six major psychiatric disorders from the Psychiatric Genomics Consortium (PGC): attention deficit hyperactivity disorder (ADHD, n = 38,691), anxiety disorder (ANX, n = 2248), bipolar disorder (BIP, n = 41,917), anorexia nervosa (AN, n = 16,992), schizophrenia (SCZ, n = 36,989), and autism spectrum disorder (ASD, n = 18,381). We conducted bidirectional Mendelian randomization (MR) analysis to explore the causal relationships between gut microbiota and psychiatric disorders. Additionally, we performed two-step MR and multivariable MR (MVMR) analyses to identify potential mediating inflammatory factors.

RESULTS

We found significant causal relationships between 11 gut microbiota and ADHD, 2 gut microbiota and ANX, 11 gut microbiota and BIP, 8 gut microbiota and AN, 15 gut microbiota and SCZ, and 5 gut microbiota and ASD. There were 16 positive and 15 negative causal effects between inflammatory factors and psychiatric disorders. Furthermore, MVMR analysis results indicated that the correlation between genus Roseburia and ADHD was mediated by MCSF, with a mediation proportion of 3.3 %; the correlation between genus Erysipelotrichaceae UCG003 and BIP was mediated by GDNF, with a mediation proportion of 3.7 %; and the correlation between family Prevotellaceae and SCZ was mediated by CD40, with a mediation proportion of 8.2 %.

CONCLUSIONS

The MR analysis results supported causal relationships between gut microbiota and six psychiatric disorders, as well as the potential mediating role of inflammatory factors. This study highlights the potential role of the gut microbiota-inflammation-brain axis in psychiatric disorders.

Gut virome and its implications in the pathogenesis and therapeutics of inflammatory bowel disease

Inflammatory bowel disease (IBD) refers to chronic, recurrent inflammatory intestinal disorders, primarily including Crohn's disease (CD) and Ulcerative colitis (UC). Numerous studies have elucidated the importance of the gut microbiome in IBD. Recently, numerous studies have focused on the gut virome, an intriguing and enigmatic aspect of the gut microbiome. Alterations in the composition of phages, eukaryotic viruses, and human endogenous retroviruses that occur in IBD suggest potential involvement of the gut virome in IBD. Nevertheless, the mechanisms by which it maintains intestinal homeostasis and interacts with diseases are only beginning to be understood. Here, we thoroughly reviewed the composition of the gut virome in both healthy individuals and IBD patients, emphasizing the key viruses implicated in the onset and progression of IBD. Furthermore, the complex connections between the gut virome and the intestinal barrier, immunity, and gut microbiome were dissected to advance the interpretation of IBD pathogenesis. The updated discussion of the evidence regarding the gut virome will advance our knowledge in gut virome and chronic gastrointestinal diseases. Targeting the gut virome is a promising avenue for IBD treatment in future.

Bacteria-derived 3-hydroxydodecanoic acid induces a potent anti-tumor immune response via the GPR84 receptor

Despite advances in cancer treatment, the development of effective therapies remains an urgent unmet need. Here, we investigate the potential of bacteria-derived metabolites as a therapeutic alternative for the treatment of cancer. We detect 3-hydroxydodecanedioic acid in the serum of tumor-bearing mice treated with serum from mice previously supplemented with a mix of Clostridiales bacteria. Further, 3-hydroxydodecanoic acid, an intermediate derivative between dodecanoic and 3-hydroxydodecanedioic acids, exhibits a strong anti-tumor response via GPR84 receptor signaling and enhances CD8+ T cell infiltration and cytotoxicity within tumor tissue in multiple cancer models. Metabolomics analysis of colorectal cancer patient serum reveals an inverse correlation between the abundance of these metabolites and advanced disease stages. Our findings provide a strong rationale for 3-hydroxydodecanoic acid and the GPR84 receptor to be considered as promising therapeutic targets for cancer treatment.

Microbiota, mitochondria, and epigenetics in health and disease: converging pathways to solve the puzzle

Dysbiosis, which refers to an imbalance in the composition of the gut microbiome, has been associated with a range of metabolic disorders, including type 2 diabetes, obesity, and metabolic syndrome. Although the exact mechanisms connecting gut dysbiosis to these conditions are not fully understood, various lines of evidence strongly suggest a substantial role for the interaction between the gut microbiome, mitochondria, and epigenetics. Current studies suggest that the gut microbiome has the potential to affect mitochondrial function and biogenesis through the production of metabolites. A well-balanced microbiota plays a pivotal role in supporting normal mitochondrial and cellular functions by providing metabolites that are essential for mitochondrial bioenergetics and signaling pathways. Conversely, in the context of illnesses, an unbalanced microbiota can impact mitochondrial function, leading to increased aerobic glycolysis, reduced oxidative phosphorylation and fatty acid oxidation, alterations in mitochondrial membrane permeability, and heightened resistance to cellular apoptosis. Mitochondrial activity can also influence the composition and function of the gut microbiota. Because of the intricate interplay between nuclear and mitochondrial communication, the nuclear epigenome can regulate mitochondrial function, and conversely, mitochondria can produce metabolic signals that initiate epigenetic changes within the nucleus. Given the epigenetic modifications triggered by metabolic signals from mitochondria in response to stress or damage, targeting an imbalanced microbiota through interventions could offer a promising strategy to alleviate the epigenetic alterations arising from disrupted mitochondrial signaling.

Coenzyme Q10 modulates the immunity by enhancing mononuclear macrophage, NK cell activity, and regulating gut microbiota

Introduction

Coenzyme Q10 (CoQ10), an important fat-soluble, bioactive molecule that predominantly found in the inner mitochondrial membrane, is widely used in functional food and health food raw materials, which has garnered considerable attention due to its potential role in immunoregulation. However, the intrinsic mechanism of CoQ10 on immunity, and the relationship to the gut microbiota have not been elucidated.

Methods

Here, we conducted a series of in vivo experiments with the aim of comprehensively exploring the effect of CoQ10 on both cellular and humoral immune functions, and on gut microbiota communities in mice.

Results

CoQ10 showed negligible impact on both mouse body weight fluctuations and tissue indices, but enhanced the mouse body immunity by elevating the carbon clearance ability and natural killer (NK) cellular viability. 16S rRNA gene sequencing revealed that administration of CoQ10 modulated the structure and composition of the gut microbiota in mice, notably by enhancing the abundance of Lactobacillus, Limosilactobacillus, and decreasing the abundance of Paramuribaculum species.

Discussion

This work makes a contribution to the application of CoQ10 as an immunomodulator in the biological, pharmaceutical and health care product industries.

Research Status and Trends of Gut Microbiota and Intestinal Diseases Based on Bibliometrics

Gut microbiota plays an important role in gut health, and its dysbiosis is closely related to the pathogenesis of various intestinal diseases. The field of gut microbiota and intestinal diseases has not yet been systematically quantified through bibliometric methods. This study conducted bibliometric analysis to delineate the evolution of research on gut microbiota and intestinal diseases. Data were sourced from the Web of Science Core Collection database from 2009 to 2023 and were scientometrically analyzed using CiteSpace. We have found that the number of annual publications has been steadily increasing and showing an upward trend. China and the Chinese Academy of Sciences are the country and institution with the most contributions, respectively. Frontiers in Microbiology and Nutrients are the journals with the most publications, while Plos One and Nature are the journals with the most citations. The field has shifted from focusing on traditional descriptive analysis of gut microbiota composition to exploring the causal relationship between gut microbiota and intestinal diseases. The research hotspots and trends mainly include the correlation between specific intestinal diseases and gut microbiota diversity, the mechanism of gut microbiota involvement in intestinal diseases, the exploration of important gut microbiota related to intestinal diseases, and the relationship between gut microbiota and human gut health. This study provides a comprehensive knowledge map of gut microbiota and intestinal diseases, highlights key research areas, and outlines potential future directions.

Harnessing the human gut microbiota: an emerging frontier in combatting multidrug-resistant bacteria

Antimicrobial resistance (AMR) has become a major and escalating global health threat, undermining the effectiveness of current antibiotic and antimicrobial therapies. The rise of multidrug-resistant bacteria has led to increasingly difficult-to-treat infections, resulting in higher morbidity, mortality, and healthcare costs. Tackling this crisis requires the development of novel antimicrobial agents, optimization of current therapeutic strategies, and global initiatives in infection surveillance and control. Recent studies highlight the crucial role of the human gut microbiota in defending against AMR pathogens. A balanced microbiota protects the body through mechanisms such as colonization resistance, positioning it as a key ally in the fight against AMR. In contrast, gut dysbiosis disrupts this defense, thereby facilitating the persistence, colonization, and dissemination of resistant pathogens. This review will explore how gut microbiota influence drug-resistant bacterial infections, its involvement in various types of AMR-related infections, and the potential for novel microbiota-targeted therapies, such as fecal microbiota transplantation, prebiotics, probiotics, phage therapy. Elucidating the interactions between gut microbiota and AMR pathogens will provide critical insights for developing novel therapeutic strategies to prevent and treat AMR infections. While previous reviews have focused on the general impact of the microbiota on human health, this review will specifically look at the latest research on the interactions between the gut microbiota and the evolution and spread of AMR, highlighting potential therapeutic strategies.

Exploring effects of gut microbiota on tertiary lymphoid structure formation for tumor immunotherapy

Anti-tumor immunity, including innate and adaptive immunity is critical in inhibiting tumorigenesis and development of tumor. The adaptive immunity needs specific lymph organs such as tertiary lymphoid structures (TLSs), which are highly correlated with improved survival outcomes in many cancers. In recent years, with increasing attention on the TLS in tumor microenvironment, TLSs have emerged as a novel target for anti-tumor therapy. Excitingly, studies have shown the contribution of TLSs to the adaptive immune responses. However, it is unclear how TLSs to form and how to more effectively defense against tumor through TLS formation. Recent studies have shown that the inflammation plays a critical role in TLS formation. Interestingly, studies have also found that gut microbiota can regulate the occurrence and development of inflammation. Therefore, we here summarize the potential effects of gut microbiota- mediated inflammation or immunosuppression on the TLS formation in tumor environments. Meanwhile, this review also explores how to manipulate mature TLS formation through regulating gut microbiota/metabolites or gut microbiota associated signal pathways for anti-tumor immunity, which potentially lead to a next-generation cancer immunotherapy.

In-depth profile of biosignatures for T2DM cohort utilizing an integrated targeted LC-MS platform

The profiling of metabolites provides an immediate snapshot that depicts crucial physiological information, holding immense potential for the early diagnosis and prognosis of diseases, including diabetes. Herein, we proposed an optimized and in-depth target-based metabolome platform through an integration of six distinct conditions, including a normal phase, a pre-column chemical derivatization and four reversed phase separation methods for the quantification of a total of 1609 small molecules (32 sub-classes) in serum after normalization using isotope-labeled internal standards. After undergoing rigorous methodological validation and comprehensive comparison with untargeted strategies, we present a new dataset of metabolomic profile encompassing a cohort of 200 healthy individuals and 100 newly diagnosed Type 2 diabetes mellitus (T2DM) patients from the northern region of China. The overall differential analysis results indicated obvious metabolic disturbance of amino acid, fatty acids, lysophosphatidyl-choline and triacylglycerol in T2DM. We hereby make these technical validation results and the profiling dataset publicly available to the scientific community, showcasing its exceptional sensitivity and robustness as an invaluable tool for the comprehensive targeted metabolome analysis.

Gut Microbiota and Metabolic Biomarkers Associated With Longevity

The dynamic balance between pro- and anti-inflammatory networks decreases as individuals age, and intestinal dysbiosis can initiate and maintain low-grade systemic inflammation. Interactions between the microbiota and humans occur from the beginning of life and, in general, the diversity of microbiota decreases with aging. The microbiome produces different metabolites with systemic effects, including immune system regulation. This understanding will be useful in controlling inflammation and preventing metabolic changes. Therefore, this review aims to identify the main metabolites synthesized by the intestinal microbiota to be used as biomarkers associated with longevity. This is a narrative review using scientific articles published in the last 10 years in the following databases: PubMed, Scielo, and Lilacs, using the Boolean operators "and" or "or." For this review, we identified 5 articles. The main metabolites described in the literature to date are organic acids, bile acids (BAs), short-chain fatty acids, branched-chain amino acids, trimethylamine N-oxide (TMAO), and derivatives of tryptophan and indole. Among these, the only ones not yet well characterized in studies on longevity were BAs and TMAO. Glutamate and p-cresol were also highlighted in the literature, with a negative association with longevity. The others showed an association, mostly positive, and can be used as potential biomarkers correlated with healthy aging and, if better studied, as targets for intervention to promote health and well-being.

Intestinal mucosal immunity and type 1 diabetes: Non-negligible communication between gut and pancreas

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by T cell-mediated pancreatic β cell loss, resulting in lifelong absolute insulin deficiency and hyperglycaemia. Environmental factors are recognized as a key contributor to the development of T1D, with the gut serving as a primary interface for environmental stimuli. Recent studies have revealed that the alterations in the intestinal microenvironment profoundly affect host immune responses, contributing to the aetiology and pathogenesis of T1D. However, the dominant intestinal immune cells and the underlying mechanisms remain incompletely elucidated. In this review, we provide an overview of the possible mechanisms of the intestinal mucosal system that underpin the pathogenesis of T1D, shedding light on the roles of both non-classical and classical immune cells in T1D. Our goal is to gain insights into how modulating these immune components may hold potential implications for T1D prevention and provide novel perspectives for immune-mediated therapy.

Genetically predicted inflammatory proteins mediate the association between gut microbiota and renal cell carcinoma

BACKGROUND

Studies have indicated a potential relationship between gut microbiota and renal cell carcinoma. However, the causal relationship between various types of gut microbiota and renal cell carcinoma, as well as the role of inflammatory protein as mediators, remains unclear.

METHODS

This study aimed to identify the relationship between gut microbiota, inflammatory protein, and renal cell cancer through a large-scale genome-wide association study (GWAS) utilizing pooled data. We employed Mendelian randomization (MR) to investigate the causal relationship among these variables. Inverse variance weighting (IVW) was utilized as the primary statistical method. Furthermore, we examined the mediating role of inflammatory protein in the pathway through which gut microbiota influences the development of renal cell cancer.

RESULTS

The analysis revealed 12 positive causal relationships and 15 negative causal relationships between the genetic liability of gut microbiota and renal cell cancer. Furthermore, there were three positive causal relationships and one negative causal relationship between inflammatory proteins and renal cell cancer. There were two axes of relationships in which gut microbiota promote the development of renal cell cancer. through inflammatory proteins acting as mediators.

CONCLUSIONS

Gut microbiota and inflammatory protein were causally related to renal cell cancer, and inflammatory protein were intermediary factors in the pathway between gut microbiota and renal cell cancer.

Transcriptomics and microbiome insights reveal the protective mechanism of mulberry-derived postbiotics against inflammation in LPS-induced mice

Background

Natural food-derived bioactive compounds have garnered increasing attention for their potential to modulate immune responses and promote gut health. In particular, compounds like mulberry-derived postbiotics (MDP) may offer novel therapeutic strategies to address inflammation, a key driver of many metabolic disorders.

Methodology

This study examines the protective effects of MDP against inflammation in LPS-induced mice, using transcriptomic and microbiome analyses to explore underlying mechanisms.

Results

MDP pretreatment alleviates LPSinduced villous atrophy and intestinal barrier damage, promoting recovery of intestinal morphology. Transcriptomic profiling revealed significant changes in gene expression, with 983 upregulated and 1220 downregulated genes in the NC vs LPS comparison, and 380 upregulated and 204 downregulated genes in the LPS vs LPS+MDP comparison. Enrichment analysis using GO and KEGG pathways revealed significant associations with transcriptional regulatory activity, and the NOD-like receptor signaling pathway among the differentially expressed genes. Protein-protein interaction analysis identified key genes involved in inflammation and immune regulation, with hub genes like IL6, CXCL10, and MYD88 in the LPS group and CD74, CIITA, and H2-AB1 in the MDP-treated group.

Conclusion

Microbiome analysis suggested MDP may also influence gut microbiota composition, supporting systemic immune regulation. These findings highlight MDP's potential as a food additive for immune modulation and gut health.

Perturbations of the endometrial immune microenvironment in endometriosis and adenomyosis: their impact on reproduction and pregnancy

The impact of endometriosis and adenomyosis on reproduction and pregnancy is significant, with both conditions linked to increased rates of infertility, poor ovarian function in women with endometriosis, and elevated pregnancy complications in those with adenomyosis. However, the underlying mechanisms remain largely unclear. Both conditions share a similar pathophysiological process characterized by the growth of ectopic endometrium, which may originate from the eutopic endometrium. Notably, surgical removal of ectopic lesions does not appear to significantly improve reproductive and pregnancy outcomes, further underscoring the importance of eutopic endometrium in these adverse effects. Emerging evidence indicates substantial differences in endometrial NK cells, macrophages, and T cells, leading to inflammatory responses in women with endometriosis and adenomyosis. These alterations may contribute not only to disease progression but also to defective endometrial receptivity, insufficient angiogenesis remodeling, impaired maternal-fetal immune tolerance, and poor placentation, thereby influencing embryo implantation and pregnancy maintenance. This provides an immunological perspective to explain the higher rates of infertility and pregnancy complications observed in affected women. Therefore, we systematically review the alterations in endometrial immune cells in women with endometriosis and adenomyosis compared to healthy controls, exploring the potential impacts of these changes on reproduction and pregnancy. This review aims to lay the groundwork for future studies on the immunopathogenesis associated with endometriosis and adenomyosis-related reproductive failure and pregnancy complications, shedding lights on the development of immunotherapeutic strategies to mitigate these adverse impacts in affected women.

Modulation of the Neuro-Cancer Connection by Metabolites of Gut Microbiota

The gut-brain-cancer axis represents a novel and intricate connection between the gut microbiota, neurobiology, and cancer progression. Recent advances have accentuated the significant role of gut microbiota metabolites in modulating systemic processes that influence both brain health and tumorigenesis. This paper explores the emerging concept of metabolite-mediated modulation within the gut-brain-cancer connection, focusing on key metabolites such as short-chain fatty acids (SCFAs), tryptophan derivatives, secondary bile acids, and lipopolysaccharides (LPS). While the gut microbiota's impact on immune regulation, neuroinflammation, and tumor development is well established, gaps remain in grasping how specific metabolites contribute to neuro-cancer interactions. We discuss novel metabolites with potential implications for neurobiology and cancer, such as indoles and polyamines, which have yet to be extensively studied. Furthermore, we review preclinical and clinical evidence linking gut dysbiosis, altered metabolite profiles, and brain tumors, showcasing limitations and research gaps, particularly in human longitudinal studies. Case studies investigating microbiota-based interventions, including dietary changes, fecal microbiota transplantation, and probiotics, demonstrate promise but also indicate hurdles in translating these findings to clinical cancer therapies. This paper concludes with a call for standardized multi-omics approaches and bi-directional research frameworks integrating microbiome, neuroscience, and oncology to develop personalized therapeutic strategies for neuro-cancer patients.

Early-life gut mycobiome core species modulate metabolic health in mice

The gut microbiome causally contributes to obesity; however, the role of fungi remains understudied. We previously identified three core species of the infant gut mycobiome (Rhodotorula mucilaginosa, Malassezia restricta and Candida albicans) that correlated with body mass index, however their causal contributions to obesity development are unknown. Here we show the effects of early-life colonization by these fungal species on metabolic health in gnotobiotic mice fed standard (SD) or high-fat-high-sucrose (HFHS) diets. Each species resulted in bacterial microbiome compositional and functional differences. R. mucilaginosa and M. restricta increased adiposity in mice fed SD, while only R. mucilaginosa exacerbated metabolic disease. In contrast, C. albicans resulted in leanness and resistance to diet-induced obesity. Intestinal nutrient transporter expression was unaffected by the presence of fungi in jejunal enteroids, yet the immune landscape in white adipose tissue was distinctly impacted by each fungal species, suggesting that these phenotypes may be a result of fungal immune regulation. This work revealed that three common fungal colonizers have distinct causal influences on obesity and metabolic inflammation and justifies the consideration of fungi in microbiome research on host metabolism.

The Inflammatory Mechanism of Parkinson's Disease: Gut Microbiota Metabolites Affect the Development of the Disease Through the Gut-Brain Axis

Parkinson's disease is recognized as the second most prevalent neurodegenerative disorder globally, with its incidence rate projected to increase alongside ongoing population growth. However, the precise etiology of Parkinson's disease remains elusive. This article explores the inflammatory mechanisms linking gut microbiota to Parkinson's disease, emphasizing alterations in gut microbiota and their metabolites that influence the disease's progression through the bidirectional transmission of inflammatory signals along the gut-brain axis. Building on this mechanistic framework, this article further discusses research methodologies and treatment strategies focused on gut microbiota metabolites, including metabolomics detection techniques, animal model investigations, and therapeutic approaches such as dietary interventions, probiotic treatments, and fecal transplantation. Ultimately, this article aims to elucidate the relationship between gut microbiota metabolites and the inflammatory mechanisms underlying Parkinson's disease, thereby paving the way for novel avenues in the research and treatment of this condition.

Gut microbiota and their metabolites in the immune response of rheumatoid arthritis: Therapeutic potential and future directions

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent joint inflammation, damage, and loss of function. In recent years, the role of gut microbiota and its metabolites in immune regulation has attracted increasing attention. The gut microbiota influences the host immune system's homeostasis through various mechanisms, regulating the differentiation, function, and immune tolerance of immune cells. Dysbiosis of the gut microbiota in RA patients is closely associated with abnormal activation of immune cells and excessive secretion of inflammatory cytokines. Metabolites produced by the gut microbiota, such as short-chain fatty acids (SCFAs), tryptophan metabolites, bile acids, and amino acid metabolites, play a critical role in immune responses, regulating the functions of immune cells like T cells, B cells, and macrophages, and inhibiting the release of pro-inflammatory cytokines. Restoring the balance of the gut microbiota and optimizing the production of metabolic products may become a new strategy for RA treatment. This review discusses the role of gut microbiota and its metabolites in the immune response of RA, exploring how they influence the immunopathological process of RA through the regulation of immune cells and key immune factors. It also provides a theoretical basis for future therapeutic strategies based on gut microbiota modulation.

Gut microbiota and atrial cardiomyopathy

Atrial cardiomyopathy is a multifaceted heart disease characterized by structural and functional abnormalities of the atria and is closely associated with atrial fibrillation and its complications. Its etiology involves a number of factors, including genetic, infectious, immunologic, and metabolic factors. Recent research has highlighted the critical role of the gut microbiota in the pathogenesis of atrial cardiomyopathy, and this is consistent with the gut-heart axis having major implications for cardiac health. The aim of this work is to bridge the knowledge gap regarding the interactions between the gut microbiota and atrial cardiomyopathy, with a particular focus on elucidating the mechanisms by which gut dysbiosis may induce atrial remodeling and dysfunction. This article provides an overview of the role of the gut microbiota in the pathogenesis of atrial cardiomyopathy, including changes in the composition of the gut microbiota and the effects of its metabolites. We also discuss how diet and exercise affect atrial cardiomyopathy by influencing the gut microbiota, as well as possible future therapeutic approaches targeting the gut-heart axis. A healthy gut microbiota can prevent disease, but ecological dysbiosis can lead to a variety of symptoms, including the induction of heart disease. We focus on the pathophysiological aspects of atrial cardiomyopathy, the impact of gut microbiota dysbiosis on atrial structure and function, and therapeutic strategies exploring modulation of the microbiota for the treatment of atrial cardiomyopathy. Finally, we discuss the role of gut microbiota in the treatment of atrial cardiomyopathy, including fecal microbiota transplantation and oral probiotics or prebiotics. Our study highlights the importance of gut microbiota homeostasis for cardiovascular health and suggests that targeted interventions on the gut microbiota may pave the way for innovative preventive and therapeutic strategies targeting atrial cardiomyopathy.

Navigating liver health with metabolomics: A comprehensive review

Non-alcoholic fatty liver disease (NAFLD) is the main cause of chronic liver disease worldwide, affecting one-fourth of the world's population. With more than half of the world's population, the Asia-Pacific region contributed 62.6 % of liver-related fatal incidents in 2015. Currently, liver imaging techniques such as computed tomography (CT), nuclear magnetic resonance (NMR) spectroscopy, and ultrasound are non-invasive imaging methods to diagnose the disease. A liver biopsy is the gold standard test for establishing the definite diagnosis of non-alcoholic steatohepatitis (NASH). However, there are still significant problems with sample variability and the procedure's invasiveness. Numerous studies have indicated various non-invasive biomarkers for both fibrosis and steatosis to counter the invasiveness of diagnostic procedures. Metabolomics could be a promising method for detecting early liver diseases, investigating pathophysiology, and developing drugs. Metabolomics, when utilized with other omics technologies, can result in a deeper understanding of biological systems. Metabolomics has emerged as a prominent research topic, offering extensive opportunities to investigate biomarkers for liver diseases that are both sensitive and specific. In this review, we have described the recent studies involving the use of a metabolomics approach in the diagnosis of liver diseases, which would be beneficial for the early detection and treatment of liver diseases.

Specific Composition Diets and Improvement of Symptoms of Immune-Mediated Inflammatory Diseases in Adulthood-Could the Comparison Between Diets Be Improved?

Diet is considered a possible cofactor, which affects the immune system and potentially causes dysregulation of intestinal homeostasis and inflammation. This study aimed to review the quality of evidence on the effects of specific diet composition on symptoms of immune-mediated inflammatory diseases (IMIDs), including rheumatoid arthritis (RA), spondyloarthritis, multiple sclerosis (MS), inflammatory bowel disease (IBD) [remission maintenance of Crohn's disease and ulcerative colitis], psoriasis and psoriatic arthritis in adult patients. We conducted a review of meta-analyses and Cochrane systematic reviews using PubMed and EMBASE, from inception to September 2024, and Google Scholar. The methodological quality of the meta-analyses was assessed using the AMSTAR 2 rating system. Three Cochrane systematic reviews and eight meta-analyses were evaluated. Some specific composition diets have been shown to reduce the symptoms of RA, IBD, and MS and improve activity parameters in IBD and RA, with critically low or low levels of evidence. The reduction in inflammatory biomarker levels is unclear. This review summarizes the global evidence for specific dietary interventions, mostly with anti-inflammatory properties due to their components, to improve IMID symptoms, clarifying the weaknesses of clinical trials and dietary meta-analyses with critically low or low levels of evidence; and shows the need to use indices such as the Dietary Inflammatory Index, which allows diets to be classified by their pro-inflammatory or anti-inflammatory food content, to better compare diet groups in clinical trials. The difficulty of obtaining high-level evidence from dietary studies is apparent and may delay the application of the results. Clinicians should be aware of the role of diets with anti-inflammatory properties as a complement to pharmacological treatments in IMIDs.

Short-Chain Fatty Acids: Promising Therapeutic Targets for Respiratory Syncytial Virus Infection

The intestinal microbiota is a complex community of organisms present in the human gastrointestinal tract, some of which can produce short-chain fatty acids (SCFAs) through the fermentation of dietary fiber. SCFAs play a major role in mediating the intestinal microbiota's regulation of host immunity and intestinal homeostasis. Respiratory syncytial virus (RSV) can cause an imbalance between anti-inflammatory and proinflammatory responses in the host. In addition, changes in SCFA levels and the structure of the intestinal microbiota have been observed after RSV infection. Therefore, there may be a link between SCFAs and RSV infection, and SCFAs are expected to be therapeutic targets for RSV infection.

Lactobacillus fermentum 016 Alleviates Mice Colitis by Modulating Oxidative Stress, Gut Microbiota, and Microbial Metabolism

Ulcerative colitis (UC) is a chronic and progressive inflammatory gastrointestinal disease closely associated with gut microbiota dysbiosis and metabolic homeostasis disruption. Although targeted microbial therapies are an emerging intervention strategy for inflammatory bowel disease (IBD), the mechanisms by which specific probiotics, such as Lactobacillus fermentum 016 (LF), alleviate UC remain unclear. The current study evaluated the effects of LF supplementation on gut health in a basal model using C57BL/6 mice. Subsequently, the preventive effects and mechanisms of LF supplementation on DSS-induced UC were systematically investigated. According to our findings, LF supplementation revealed immunoregulatory capabilities with significantly altered gut the composition of microbiota and metabolic activities, particularly enhancing tryptophan metabolism. In the UC model, LF supplementation effectively mitigated weight loss, increased the disease activity index (DAI), and alleviated diarrhea, rectal bleeding, and colon shortening. Moreover, it reduced colonic pathological damage and histological injury scores. LF intervention improved antioxidant markers and intestinal mucosal barrier function with the activation of the Nrf2-Keap1 signaling pathway and regulation of systemic inflammatory markers, i.e., IL-1β, IL-6, TNF-α, IFN-γ, IL-4, and IL-10. Importantly, LF supplementation reversed metabolic disturbances by significantly increasing the abundance of beneficial genera (e.g., g_Dubosiella, g_Faecalibaculum, g_Odoribacter, g_Candidatus_saccharimonas, g_Roseburia, and g_Eubacterium_xylanophilum_group) and elevating tryptophan metabolites (e.g., melatonin, kynurenic acid, 3-indoleacetic acid, 5-methoxytryptophan, and 5-hydroxyindoleacetic acid). In conclusion, Lactobacillus fermentum 016 exhibits potential for regulating gut microbiota homeostasis, enhancing tryptophan metabolism, and alleviating UC, providing critical insights for developing probiotic-based precision therapeutic strategies for IBD.

Bifidobacterium animalis BD400 protects from collagen-induced arthritis through histidine metabolism

Background

Rheumatoid arthritis (RA) is a common chronic and systemic autoimmune disease. Numerous clinical studies have indicated a correlation between alterations in gut microbiota and the onset and progression of RA. This research aims to restore intestinal microbiota to a healthy state through the oral administration of Bifidobacterium in the early stages with the goal of delaying the onset and progression of RA.

Methods

Collagen-induced arthritis (CIA) rat model was constructed to assess the development of RA using arthritis clinical scores, paw thickness, pathological analysis of knee joint. The immune response was evaluated by determinating specific antibodies and cytokines in serum and synovial fluid. The expression of intestinal barrier protein was analyzed by qPCR to evaluate the intestinal barrier function. Alterations in gut microbiota and metabolites were assessed by 16S rDNA and non-targeted metabolomics.

Results

The findings reveal that administering Bifidobacterium animalis BD400 orally led to a significant reduction in arthritis clinical scores and paw swelling thickness in CIA rats. Additionally, there was a decrease in osteo-facial fusion and calcified cartilage thickening in the knee joint. Furthermore, the oral administration of B. animalis BD400 resulted in the down-regulation of inflammatory factors TNF-α and collagenase MMP-13 in the knee joint. Levels of specific antibodies (anti-CII IgG, anti-CII IgG1, and anti-CII IgG2a) and cytokine IL-17A in serum, as well as cytokines (TNF-α and IL-1β) in the synovial fluid of B. animalis BD400-treated CIA rats, were significantly reduced (p < 0.05). The gene expression levels of intestinal barrier proteins (occludin-1, MUC-2, and ZO-1) showed a significant increase (p < 0.05) in B. animalis BD400-treated CIA rats. The oral administration of B. animalis BD400 altered the composition of intestinal microorganisms in CIA rats at the phylum and genus levels, particularly affecting the genus HT002. B. animalis BD400 alleviates RA by down-regulating 1-methyl-L-histidine and urocanate in the histidine metabolism, laying a foundation for the RA prevention.

Conclusion

By affecting genus HT002 and histidine metabolism in the gut microbiota of CIA rats, B. animalis BD400 restored intestinal permeability, inhibited systemic inflammatory response, and ultimately slowed down the development of RA.

The direct and indirect inhibition of proinflammatory adipose tissue macrophages by acarbose in diet-induced obesity

Inflammation is critical for obesity and obesity-induced insulin resistance (IR). In this study, we reveal the function and mechanism of acarbose on adipose tissue macrophage (ATM)-mediated inflammation in obesity and obesity-induced IR. First, acarbose enhances the abundance of propionic acid-producing Parasutterella, therefore indirectly inhibiting the survival and proinflammatory function of M1-like ATMs via GPR43. Most interestingly, acarbose can directly inhibit M1-like ATM-mediated inflammation through GPR120. Diet-induced obese mice exhibit nitrobenzoxadiazoles (NBD) fluorescence-labeled ATMs, but lean mice that also orally received NBD fluorescence-labeled acarbose do not exhibit NBD fluorescence-labeled ATMs. This direct inhibition of macrophages by acarbose is validated in mouse and human macrophages in vitro. In conclusion, our study reveals that acarbose directly and indirectly inhibits proinflammatory macrophage phenotype, which contributes to the improvement of obesity and obesity-induced IR. The understanding of the immune regulatory effects of acarbose may extend its potential for further therapeutic applications.

New approaches to secondary metabolite discovery from anaerobic gut microbes

The animal gut microbiome is a complex system of diverse, predominantly anaerobic microbiota with secondary metabolite potential. These metabolites likely play roles in shaping microbial community membership and influencing animal host health. As such, novel secondary metabolites from gut microbes hold significant biotechnological and therapeutic interest. Despite their potential, gut microbes are largely untapped for secondary metabolites, with gut fungi and obligate anaerobes being particularly under-explored. To advance understanding of these metabolites, culture-based and (meta)genome-based approaches are essential. Culture-based approaches enable isolation, cultivation, and direct study of gut microbes, and (meta)genome-based approaches utilize in silico tools to mine biosynthetic gene clusters (BGCs) from microbes that have not yet been successfully cultured. In this mini-review, we highlight recent innovations in this area, including anaerobic biofoundries like ExFAB, the NSF BioFoundry for Extreme & Exceptional Fungi, Archaea, and Bacteria. These facilities enable high-throughput workflows to study oxygen-sensitive microbes and biosynthetic machinery. Such recent advances promise to improve our understanding of the gut microbiome and its secondary metabolism. KEY POINTS: • Gut microbial secondary metabolites have therapeutic and biotechnological potential • Culture- and (meta)genome-based workflows drive gut anaerobe metabolite discovery • Anaerobic biofoundries enable high-throughput workflows for metabolite discovery.

Murine gut microbiota dysbiosis via enteric infection modulates the foreign body response to a distal biomaterial implant

The gut microbiota influences systemic immunity and the function of distal tissues, including the brain, liver, skin, lung, and muscle. However, the role of the gut microbiota in the foreign body response (FBR) and fibrosis around medical implants is largely unexplored. To investigate this connection, we perturbed the homeostasis of the murine gut microbiota via enterotoxigenic Bacteroides fragilis (ETBF) infection and implanted the synthetic polymer polycaprolactone (PCL) into a distal muscle injury. ETBF infection in mice led to increased neutrophil and γδ T cell infiltration into the PCL implant site. ETBF infection alone promoted systemic inflammation and increased levels of neutrophils in the blood, spleen, and bone marrow. At the PCL implant site, we found significant changes in the transcriptome of sorted fibroblasts but did not observe gross ETBF- induced differences in the fibrosis levels after 6 weeks. These results demonstrate the ability of the gut microbiota to mediate long-distance effects such as immune and stromal responses to a distal biomaterial implant.

Significance Statement

The foreign body response to implants leads to chronic inflammation and fibrosis that can be highly variable in the general patient population. Here, we demonstrate that gut dysbiosis via enteric infection promoted systemic inflammation and increased immune cell recruitment to an anatomically distant implant site. These results implicate the gut microbiota as a potential source of variability in the clinical biomaterial response and illustrate that the local tissue environment can be influenced by host factors that modulate systemic interactions.

Supplementation with Complex Phytonutrients Enhances Rumen Barrier Function and Growth Performance of Lambs by Regulating Rumen Microbiome and Metabolome

Complex phytonutrients (CPS) have attracted extensive interest due to their anti-inflammatory effects. This investigation focused on the impact of CPS on rumen health in lambs on high-concentrate diets, emphasizing growth performance, ruminal fermentation, epithelial barrier integrity, ruminal metabolism, and microbial communities. A total of 54 lambs, 3 months old and with a 30.42 ± 0.54 kg body weight, were randomly assigned to three treatment groups, with six replicates per treatment and three lambs per replicate. The lambs received a basal diet (the ratio of concentrate to forage was 75:25) without CPS supplementation (CON) or with the inclusion of 2.5 g/kg (CPS2.5) or 5.0 g/kg CPS (CPS5.0) for a total of 60 days. The CPS groups exhibited increased growth performance and improved rumen fermentation parameters. Mechanistically, CPS enhanced rumen epithelial barrier function, thereby lowering inflammation and inhibiting the overactivation of the JNK/p38 MAPK signaling pathway, and the effect of CPS5.0 was better than that of CPS2.5. Notably, CPS5.0 could optimize the composition of rumen microbiota and increase the levels of Ursolic acid and other metabolites. The strong associations between rumen bacteria and health-related indicators and differential metabolites were further highlighted. Our findings suggest that adding CPS to lambs' diets has widespread positive impacts, including improved growth performance, reduced inflammation and mRNA relative expression of apoptosis-related genes, enhanced barrier function, and beneficial changes in the rumen microbiome and metabolite profiles.

Deer oil improves ulcerative colitis induced by DSS in mice by regulating the intestinal microbiota and SCFAs metabolism and modulating NF-κB and Nrf2 signaling pathways

BACKGROUND

Deer oil (DO), a byproduct of deer meat processing, possesses high nutritional value. This study aims to evaluate the protective effects of DO on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice and to explore its potential mechanisms of action.

RESULTS

DO was found to inhibit weight loss and colon shortening in colitis mice, significantly reduce disease activity index scores, and notably enhance the levels of tight junction proteins in colon tissues, thus improving intestinal barrier function. ELISA results indicated that DO markedly alleviated the mice's oxidative stress and inflammatory responses. Western blot analysis further demonstrated that DO significantly inhibited the phosphorylation of NF-κB while up-regulating the expression levels of Nrf2 and HO-1 proteins. Additionally, DO increased the abundance of beneficial bacteria such as Odoribacter, Blautia, and Muribaculum, reduced the abundance of harmful bacteria such as Bacteroides, Helicobacter, and Escherichia-Shigella, and promoted the production of short-chain fatty acids.

CONCLUSION

Our study provides the first evidence that DO can effectively improve DSS-induced UC in mice. The underlying mechanisms may involve maintaining intestinal barrier function, inhibiting inflammation, alleviating oxidative stress, and modulation of gut microbiota. These findings offer valuable insights for developing DO as an adjunct treatment for UC and as a functional food. © 2024 Society of Chemical Industry.

Fibre: The Forgotten Carbohydrate in Sports Nutrition Recommendations

Although dietary guidelines concerning carbohydrate intake for athletes are well established, these do not include recommendations for daily fibre intake. However, there are many scenarios in sports nutrition in which common practice involves the manipulation of fibre intake to address gastrointestinal comfort around exercise, or acute or chronic goals around the management of body mass or composition. The effect of fibre intake in overall health is also important, particularly in combination with other dietary considerations such as the elevated protein requirements in this population. An athlete's habitual intake of dietary fibre should be assessed. If less than 20 g a day, athletes may consider dietary interventions to gradually increase intake. It is proposed that a ramp phase is adopted to gradually increase fibre ingestion to ~ 30 g of fibre a day (which includes ~ 2 g of beta-glucan) over a duration of 6 weeks. The outcomes of achieving a daily fibre intake are to help preserve athlete gut microbiome diversity and stability, intestinal barrier function as well as the downstream effects of short-chain fatty acids produced following the fermentation of microbiome accessible carbohydrates. Nevertheless, there are scenarios in which daily manipulation of fibre intake, either to reduce or increase intake, may be valuable in assisting the athlete to maintain gastrointestinal comfort during exercise or to contribute to body mass/composition goals. Although further research is required, the aim of this current opinion paper is to ensure that fibre is not forgotten as a nutrient in the athlete's diet.

Effect of radiotherapy exposure on fruquintinib plus sintilimab treatment in refractory microsatellite stable metastatic colorectal cancer: a prospective observation study

BACKGROUND

Immune checkpoint inhibitors (ICIs) in combination with antiangiogenic drugs have shown promising outcomes in the third-line and subsequent treatments of patients with microsatellite stable metastatic colorectal cancer (MSS-mCRC). Radiotherapy (RT) may enhance the antitumor effect of immunotherapy. However, the effect of RT exposure on patients receiving ICIs and targeted therapy remains unclear. This study aimed to investigate the association between RT exposure and clinical responses to fruquintinib (a highly selective tyrosine kinase inhibitor of vascular endothelial growth factor receptor) plus sintilimab (an anti-programmed death 1 antibody; F&S) in previously treated patients with MSS-mCRC and to explore predictive biomarkers.

METHODS

In this prospective observational study, patients with mCRC receiving F&S as third-line or subsequent treatment were enrolled. Eligible patients were divided into the RT cohort (RTC) and the non-RT cohort (NRTC) according to their RT history. The primary endpoint was the objective response rate (ORR). Secondary endpoints included disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. Pretreatment fecal and serum samples were collected for microbiome analysis, metabolome analysis, and immune signatures to identify biomarkers for treatment.

RESULTS

A total of 55 patients were included, of which 25 were in the RTC and 30 in the NRTC. Better ORR (28.0% vs 6.7%, p=0.048), DCR (80.0% vs 36.7%, p=0.002), median PFS (6.2 vs 2.7 months, p<0.001), and median OS (14.8 vs 5.9 months, p=0.019) were noted in patients with RTC than those with NRTC. The enrichment of Lactobacillus, Bifidobacterium, and PC(20:5(5Z,8Z,11Z,14Z,17Z)/20:3(8Z,11Z,14Z)) in RTC significantly predicted better DCR and PFS, whereas guanosine and interleukin-10 predominated in patients with NRTC were negatively correlated with PFS and OS.

CONCLUSIONS

Patients with RT exposure benefited significantly from F&S in the third-line or subsequent treatment for MSS-mCRC. Gut microbiota, metabolites, and cytokines may help predict F&S outcomes for mCRC, which may be helpful in treatment decision-making.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier: NCT05635149.

Ecological and evolutionary responses of earthworm holobionts to environmental changes

Global environmental change substantially affects soil detritivores, including earthworms, impacting host-microbiota interactions and altering key soil biogeochemical processes such as litter decomposition. As microbial communities are inherently capable of rapid evolution, responses of earthworms and associated microbiota (i.e. earthworm holobionts) to global environmental change may likely involve the interplay of ecological and evolutionary processes and feedback. Although species-level responses of earthworms to global environmental change are well studied, the potential ecological and evolutionary responses of earthworm holobionts to environmental change remain unexplored. Here, we provide a conceptual framework to elaborate on the complex network of earthworm host-microbiota interactions that modify their traits in response to global environmental change, jointly shaping their ecology and evolution. Based on the literature, we synthesize evidence of global environmental change impacts on earthworm host-microbiota and discuss evidence of their ecological and evolutionary responses to environmental change. Lastly, we highlight the agro- and eco-system-level consequences of environmental change-mediated shift in earthworm host-microbiota functions. Soil legacies of environmental change have cascading detrimental impacts on the abundance, diversity, and functional dynamics of earthworm host-microbiota interactions in agriculture and ecosystems. The primary mechanisms driving such responses of earthworm hosts and associated microbial communities to environmental change include altered litter quality and host dietary preferences, competitive interactions and exclusion, habitat homogenization, and a shift in soil physicochemical and biological processes. Therefore, advancing knowledge of the intricate animal-microorganism interactions is crucial for belowground biodiversity management in a changing global environment.

Astragalus polysaccharide alleviates mastitis disrupted by Staphylococcus aureus infection by regulating gut microbiota and SCFAs metabolism

Polysaccharides, key bioactive compounds derived from Chinese herbs, are increasingly recognized for their therapeutic potential in modulating gut microbiota to treat various diseases. However, their efficacy in alleviating mammary inflammation and oxidative stress and protecting the blood-milk barrier (BMB) compromised by Staphylococcus aureus (S. au) infection remains uncertain. As evidence for the gut-mammary axis grows, identifying natural prebiotic components that affect this axis is crucial. This study reveals that Astragalus polysaccharide (APS), the primary active constituent of Astragalus, effectively mitigates S. au infection in murine mammary glands, suppresses inflammatory responses, reduces oxidative stress, and restores BMB integrity. The involvement of APS in modulating gut microbiota was substantiated through gut microbial depletion experiments and fecal microbiota transplantation (FMT). Notably, APS uniquely enriched Ruminococcus bromii (R. bromii) in the gut, facilitating the metabolism of short-chain fatty acids (SCFAs), particularly acetate and butyrate, which are pivotal to APS's protective effects. Collectively, these results propose a novel therapeutic approach for the treatment and prevention of S. au-induced mastitis, leveraging APS and R. bromii as prebiotics and probiotics, respectively.

Tibial cortex transverse transport surgery improves wound healing in patients with severe type 2 DFUs by activating a systemic immune response: a cross-sectional study

BACKGROUND

Tibial cortex transverse transport (TTT) surgery has become an ideal treatment for patients with type 2 severe diabetic foot ulcerations (DFUs), while conventional treatments are ineffective. Based on our clinical practice experience, the protective immune response from TTT surgery may play a role against infections to promote wound healing in patients with DFUs. Therefore, this research aimed to systematically study the specific clinical efficacy and the mechanism of TTT surgery.

MATERIALS AND METHODS

Between June 2022 and September 2023, 68 patients with type 2 severe DFUs were enrolled and therapized by TTT surgery in this cross-sectional and experimental study. Major clinical outcomes, including limb salvage rate and antibiotics usage rate, were investigated. Ten clinical characteristics and laboratory features of glucose metabolism and kidney function were statistically analyzed. Blood samples from six key time points of TTT surgery were collected for label-free proteomics and clinical immune biomarker analysis. Besides, tissue samples from three key time points were used for spatially resolved metabolomics and transcriptomics analysis, as well as applied to validate the key TTT-regulated molecules by reverse-transcription quantitative PCR.

RESULTS

Notably, 64.7% of patients did not use antibiotics during the entire TTT surgery. TTT surgery can achieve a high limb salvage rate of 92.6% in patients with unilateral or bilateral DFUs. Pathway analysis of a total of 252 differentially expressed proteins from the proteomic revealed that the immune response induced by TTT surgery at different stages was first comprehensively verified through multiomics combined with immune biomarker analysis. The function of upward transport was activating the systemic immune response, and wound healing occurs with downward transport. The spatial metabolic characteristics of skin tissue from patients with DFUs indicated downregulated levels of stearoylcarnitine and the glycerophospholipid metabolism pathway in skin tissue from patients with severe DFUs. Finally, the expressions of PRNP (prion protein) to activate the immune response, PLCB3 (phospholipase C beta 3) and VE-cadherin play roles in neovascularization, and PPDPF (pancreatic progenitor cell differentiation and proliferation factor), LAMC2 (laminin subunit gamma 2), and SPRR2G (small proline-rich protein 2G) to facilitate the developmental process mainly keratinocyte differentiation were statistically significant in skin tissues through transcriptomic and reverse-transcription quantitative PCR analysis.

CONCLUSION

TTT surgery demonstrates favorable outcomes for patients with severe type 2 DFUs by activating a systemic immune response, contributing to anti-infection, ulcer recurrence, and the limb salvage for unilateral or bilateral DFUs. The specific clinical immune responses, candidate proteins, genes, and metabolic characteristics provide directions for in-depth mechanistic research on TTT surgery. Further research and public awareness are needed to optimize TTT surgery in patients with severe type 2 DFUs.

The mechanism by which intestinal flora metabolites regulate ILC2s transformation and intestinal immunity through the metabolite-sensitive receptor Ffar2

OBJECTIVE

The objective of this article was to investigate how the metabolites produced by the intestinal flora regulate the transformation of ILC2s and intestinal immunity via the receptor Ffar2, which is sensitive to metabolites.

MATERIALS AND METHODS

Forty male C57BL/6 mice with wild-type characteristics (6-7 weeks in age) and 20 FFAR2-/- mice were acquired from The Jackson Laboratory. The mice were kept in a controlled environment without any disease-causing agents, with the help of air conditioning and a 12-hour cycle of light and darkness. Throughout the experiment, every mouse was provided with unrestricted availability of both food and water. All protocols were performed following the Regulations of Animal Welfare and the recommendations for Animal Testing. According to the research protocol, the mice were categorized into three groups, each consisting of 20 mice. FFAR2-/- mice in the FFAR2-/- group were reared in conventional environments. Male C57BL/6 mice with wild-type characteristics were reared in conventional conditions in the wild-type group. In the group where wild-type mice were inhibited with Ffar2, a total of 20 mice with the wild-type phenotype were chosen to receive intraperitoneal injection of an FFAR2 antagonist at a dosage of 5 mg/kg per day for a continuous period of 3 weeks. qRT-PCR was used to detect the expression of FFAR2 mRNA in the mucosal tissue of the mouse colon. High-throughput sequencing was used to conduct an examination of metabolites in the intestinal tract of mice. Flow cytometry was used to test the quantity of ILC2s. ELISA was used to measure the levels of IL-5 and IL-13 in cellular mouse intestinal mucosal tissues. Flow cytometry was used to detect the quantity of CD4+ and CD8+ T cells. CCL20 and CCL25 expression was analyzed by Western blotting. The level of FFAR2 mRNA expression was higher in the wild-type group than the FFAR2-/- group ( P < 0.05), while it was lower in the wild-type + Ffar2 inhibition group than the wild-type group ( P < 0.05). No variations were observed in the composition of metabolites and levels of major SCFAs in the gut microbiota of mice across all groups ( P > 0.05). The quantity of CRTH2+ and ST2+ cells in the wild-type category exceeded that in the FFAR2-/- category ( P < 0.05), whereas the quantity of CRTH2+ and ST2+ cells in the wild-type + Ffar2 inhibition category was lower than that in the wild-type category ( P < 0.05). The concentrations of IL-5 and IL-13 were higher in the wild-type group compared with the FFAR2-/- group ( P < 0.05), while the wild-type + Ffar2 inhibition group exhibited lower levels of IL-5 and IL-13 than the wild-type group ( P < 0.05). The count of CD4+ T cells and CD8+ T cells in the wild-type group showed an increase in comparison to the FFAR2-/- group ( P < 0.05), whereas the count of CD4+ T cells and CD8+ T cells in the wild-type + Ffar2 inhibition group exhibited a decrease in comparison to the wild-type group ( P < 0.05). The levels of protein expression for CCL20 and CCL25 were higher in the wild-type group compared with the FFAR2-/- group ( P < 0.05), whereas the wild-type + Ffar2 inhibition group exhibited lower protein expression of CCL20 and CCL25 than the wild-type group ( P < 0.05).

CONCLUSION

Ffar2 has a significant regulatory function in the conversion of ILC2s, consequently impacting the immune response in the intestines. Ffar2, a crucial receptor for metabolites produced by the intestinal flora, plays a vital function in controlling the conversion of ILC2s and the overall immune response in the intestines.

Gut microbiome-gut brain axis-depression: interconnection

OBJECTIVES

The relationship between the gut microbiome and mental health, particularly depression, has gained significant attention. This review explores the connection between microbial metabolites, dysbiosis, and depression. The gut microbiome, comprising diverse microorganisms, maintains physiological balance and influences health through the gut-brain axis, a communication pathway between the gut and the central nervous system.

METHODS

Dysbiosis, an imbalance in the gut microbiome, disrupts this axis and worsens depressive symptoms. Factors like diet, antibiotics, and lifestyle can cause this imbalance, leading to changes in microbial composition, metabolism, and immune responses. This imbalance can induce inflammation, disrupt neurotransmitter regulation, and affect hormonal and epigenetic processes, all linked to depression.

RESULTS

Microbial metabolites, such as short-chain fatty acids and neurotransmitters, are key to gut-brain communication, influencing immune regulation and mood. The altered production of these metabolites is associated with depression. While progress has been made in understanding the gut-brain axis, more research is needed to clarify causative relationships and develop new treatments. The emerging field of psychobiotics and microbiome-targeted therapies shows promise for innovative depression treatments by harnessing the gut microbiome's potential.

CONCLUSIONS

Epigenetic mechanisms, including DNA methylation and histone modifications, are crucial in how the gut microbiota impacts mental health. Understanding these mechanisms offers new prospects for preventing and treating depression through the gut-brain axis.

Celiac Disease, Gluten-Free Diet, and Eating Disorders: From Bench to Bedside

Celiac disease (CD) and eating disorders (EDs) are complex chronic conditions in adolescents, sharing symptoms such as weight change, malnutrition, and gastrointestinal symptoms. CD, an autoimmune disorder triggered by gluten ingestion, is managed through a strict gluten-free diet that can unintentionally foster disordered eating behaviors due to dietary restrictions. Conversely, EDs may mask and complicate CD symptoms, leading to diagnostic delays and treatment challenges. Evidence reveals an increased risk of EDs in CD individuals and vice versa, indicating a potential bidirectional relationship. This review explores the mechanisms and clinical implications of this interplay and proposes integrated screening and care strategies to improve the quality of life for individuals with both conditions.

Microbiota-related metabolites correlated with the severity of COVID-19 patients

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a global pandemic with high mortality, and the treatment options for the severe patients remain limited. Previous studies reported the altered gut microbiota in severe COVID-19. But there are no comprehensive data on the role of microbial metabolites in COVID-19 patients.

METHODS

We identified 153 serum microbial metabolites and assessed the changes in 72 COVID-19 patients upon admission and one-month after their discharge, comparing these changes to those in 133 healthy control individuals from the outpatient department during the same period.

RESULTS

Our study revealed that microbial metabolites varied across different stages and severity of COVID-19 patients. These altered microbial metabolites included tryptophan, bile acids, fatty acids, amino acids, vitamins and those containing benzene. A total of 13 distinct microbial metabolites were identified in COVID-19 patients compared to healthy controls. Notably, correlations were found among these disrupted metabolites and organ injury and inflammatory responses related to COVID-19. Furthermore, these metabolites did not restore to the normal levels one month after discharge. Importantly, two microbial metabolites were the core microbial metabolites related to the severity of COVID-19 patients.

CONCLUSIONS

The microbial metabolites were altered in the acute and recovery stage, correlating with disease severity of COVID-19. These results indicated the important role of gut microbiota in the progression of COVID-19, and facilitated the potential therapeutic microbial target for severe COVID-19 patients.

Mechanisms of gut homeostasis regulating Th17/Treg cell balance in PMOP

Postmenopausal osteoporosis (PMOP) is a metabolic bone disease driven by estrogen deficiency, primarily manifesting as reduced bone mass and heightened fracture risk. Its development is intricately linked to the balance between Th17 and Treg cells. Recent studies have highlighted the significant role of gut homeostasis in PMOP. The gut microbiota profoundly impacts bone health by modulating the host's immune system, metabolic pathways, and endocrine functions. In particular, the regulation of Th17 and Treg cell balance by gut homeostasis plays a pivotal role in the onset and progression of PMOP. Th17 cells secrete pro-inflammatory cytokines that stimulate osteoclast activity, accelerating bone resorption, while Treg cells counteract this process through anti-inflammatory mechanisms, preserving bone mass. The gut microbiota and its metabolites can influence Th17/Treg equilibrium, thereby modulating bone metabolism. Furthermore, the integrity of the gut barrier is critical for systemic immune stability, and its disruption can lead to immune dysregulation and metabolic imbalances. Thus, targeting gut homeostasis to restore Th17/Treg balance offers a novel therapeutic avenue for the prevention and treatment of PMOP.

Brassica rapa L. crude polysaccharide meditated synbiotic fermented whey beverage ameliorates hypobaric hypoxia induced intestinal damage

Hypobaric hypoxia causes oxidative stress and inflammatory responses and disrupts the gut microbiome and metabolome. In this study, we developed a synbiotic fermented whey beverage, combining kefir and Brassica rapa L. crude polysaccharides, to explore its protective effects against high-altitude induced injury in mice. The beverage, formulated with 0.8% (w/v) polysaccharides and kefir inoculation, demonstrated robust fermentation parameters and antioxidative capacity. When applied to a hypobaric hypoxia mouse model, the synbiotic fermented whey significantly reduced oxidation and protected the intestinal barrier by lowering inflammation, protecting the intestinal structure, increasing goblet cell counts, and reducing apoptosis. It also modulated the gut microbiota, enriching beneficial taxa as Intestinimonas and Butyricicoccaceae, while reducing harmful ones like Marvinbryantia and Proteus, and enhancing short-chain fatty acid (SCFA) production. Notably, the beverage increased berberine and nicotinic acid levels, activating the adenosine monophosphate-activated protein kinase (AMPK) signalling pathway and influencing nicotinate and nicotinamide metabolites linked to the suppression of Marvinbryantia, thereby alleviating intestinal inflammation and barrier damage. These effects contributed to the alleviation of hypoxia-induced intestinal damage in mice. This study highlights the potential of synbiotics and whey fermentation in novel nutritional interventions in high altitude environments.

Emerging Biomarkers in Metabolomics: Advancements in Precision Health and Disease Diagnosis

Metabolomics has come to the fore as an efficient tool in the search for biomarkers that are critical for precision health approaches and improved diagnostics. This review will outline recent advances in biomarker discovery based on metabolomics, focusing on metabolomics biomarkers reported in cancer, neurodegenerative disorders, cardiovascular diseases, and metabolic health. In cancer, metabolomics provides evidence for unique oncometabolites that are important for early disease detection and monitoring of treatment responses. Metabolite profiling for conditions such as neurodegenerative and mental health disorders can offer early diagnosis and mechanisms into the disease especially in Alzheimer's and Parkinson's diseases. In addition to these, lipid biomarkers and other metabolites relating to cardiovascular and metabolic disorders are promising for patient stratification and personalized treatment. The gut microbiome and environmental exposure also feature among the influential factors in biomarker discovery because they sculpt individual metabolic profiles, impacting overall health. Further, we discuss technological advances in metabolomics, current clinical applications, and the challenges faced by metabolomics biomarker validation toward precision medicine. Finally, this review discusses future opportunities regarding the integration of metabolomics into routine healthcare to enable preventive and personalized approaches.

Lymphocytes and innate immune cells in acute kidney injury and repair

Acute kidney injury (AKI) is a common and serious disease entity that affects native kidneys and allografts but for which no specific treatments exist. Complex intrarenal inflammatory processes driven by lymphocytes and innate immune cells have key roles in the development and progression of AKI. Many studies have focused on prevention of early injury in AKI. However, most patients with AKI present after injury is already established. Increasing research is therefore focusing on mechanisms of renal repair following AKI and prevention of progression from AKI to chronic kidney disease. CD4+ and CD8+ T cells, B cells and neutrophils are probably involved in the development and progression of AKI, whereas regulatory T cells, double-negative T cells and type 2 innate lymphoid cells have protective roles. Several immune cells, such as macrophages and natural killer T cells, can have both deleterious and protective effects, depending on their subtype and/or the stage of AKI. The immune system not only participates in injury and repair processes during AKI but also has a role in mediating AKI-induced distant organ dysfunction. Targeted manipulation of immune cells is a promising therapeutic strategy to improve AKI outcomes.

Metabolomics: Unveiling biological matrices in precision nutrition and health

Precision nutrition, an expanding field at the intersection of nutrition science and personalized medicine, is rapidly evolving with metabolomics integration. Metabolomics, facilitated by advanced technologies like mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy, facilitates comprehensive profiling of metabolites across diverse biological samples. From the perspective of health care systems, precision nutrition gains relevance due to the substantial impact of prevalent non-communicable diseases (NCDs) on societal well-being, which is directly linked with dietary habits and eating behavior. Furthermore, biomarker products derived from metabolomics have been utilized in Europe, the USA, and Brazil to understand metabolic dysregulations and tailor diets accordingly. Despite its burgeoning status, metabolomics holds great potential in revolutionizing nutritional science, particularly with the integration of artificial intelligence and machine learning, offering novel insights into personalized dietary interventions and disease prediction. This narrative review emphasizes the transformative impact of metabolomics in precision and delineates avenues for future research and application, paving the way for a more tailored and practical approach to nutrition management.

Causal Relationships Between Gut Microbiota, Immune Cell and Pancreatic Cancer: A Two-Step, Two-Sample Mendelian Randomization Study

Background

Gut microbiota (GM) is associated with both the occurrence and development of pancreatic cancer (PC), and immune cells potentially play a role in this process. This study sought to evaluate the causative effect of GM on PC and to ascertain possible immune cell mediators.

Methods

The study primarily employed a two-step, two-sample Mendelian randomization (MR) analysis to explore the causal relationship between GM and PC within the European population, placing particular emphasis on the application of the inverse variance weighted (IVW) approach. Additionally, mediation analysis was conducted to explore the potential influence of immune cells as mediators.

Results

The MR analysis revealed a significant association between Geminocystis and the risk of PC. Increased abundance of Geminocystis was positively associated with the risk of PC (odds ratio (OR): 2.580, 95% confidence interval (CI): 1.050 - 6.342). The validity of the outcomes was also verified by the sensitivity analysis. The mediation MR analysis showed that the B-cell absolute count served as a partial intermediary in the causal link between Geminocystis and the risk of PC, contributing to 15.321% of the mediating impact.

Conclusion

This MR study demonstrated that Geminocystis has a causal relationship with PC and potentially mediates B-cell absolute count in the TBNK panel.

Polysaccharides from fermented garlic attenuate high-fat diet-induced obesity in mice through gut microbes

The weight loss and lipid-lowering effects of fermented garlic polysaccharides (BGP) in obese mice were analyzed by detecting the intestinal flora and short-chain fatty acids. An obesity model was established by feeding mice a high-fat diet (HFD) for 8 weeks. After euthanasia, biochemical index testing and hematoxylin and eosin staining were performed. Spearman analysis was used to assess the relationship between the 16S rRNA sequencing results and the fatty acid content in mouse feces. Compared with the obese model mice, the BGP group had significantly reduced body weight and serum triglycerides, total cholesterol, low-density lipoprotein cholesterol, malondialdehyde, and free fatty acids in the serum. Moreover, BGP reversed HFD-induced gut microbiota dysbiosis, as indicated by the elevated populations of Paraclostridium, Lachnospiraceae_UCG_006, Enterorhabdus, and Lachnospiraceae-NK4A136. BGP also significantly increased the contents of acetic, propionic, butyric, and valeric acids. These results indicate that BGP may serve as a potential prebiotic agent that modulates particular bacteria in the gut and their byproducts that play a crucial role in preventing diseases associated with obesity.