Bifidobacterium longum CECT 7894 Improves the Efficacy of Infliximab for DSS-Induced Colitis via Regulating the Gut Microbiota and Bile Acid Metabolism

Distinct signatures of gut microbiota and metabolites in primary biliary cholangitis with poor biochemical response after ursodeoxycholic acid treatment

BACKGROUND

About 1/3 of primary biliary cholangitis (PBC) patients suffered from poor response worldwide. And these patients present intestinal disturbances. We aimed to identify signatures of microbiota and metabolites in PBC patients with poor response, comparing to patients with response.

METHODS

This study enrolled 25 subjects (14 PBC patients with response and 11 PBC patients with poor response). Metatranscriptomics and metabolomics analysis were carried out on their fecal.

RESULTS

PBC patients with poor response had significant differences in the composition of bacteria, characterized by decreased Gemmiger etc. and increased Ruminococcus etc. The differential microbiota functions characterized by decreased abundance of elongation factor Tu and elongation factor G base on the KO database, as well as decreased abundance of Replicase large subunit etc. based on the SWISS-PROT database. PBC with poor response also had significant differences in 17 kinds of bacterial metabolites, characterized by decreased level of metabolites vital in bile acids metabolism pathway (L-Cysteine etc.) and the all-trans-Retinoic acid, a kind of immune related metabolite. The altered microbiota was associated with the differential expressed metabolites and clinical liver function indicators. 1 bacterial genera, 2 bacterial species and 9 metabolites simultaneously discriminated PBC with poor response from PBC with response with high accuracy.

CONCLUSION

PBC patients with poor response exhibit unique changes in microbiota and metabolite. Gut microbiota and metabolite-based algorithms could be used as additional tools for differential prediction of PBC with poor prognosis.

Exploring the significance of microbiota metabolites in rheumatoid arthritis: uncovering their contribution from disease development to biomarker potential

Rheumatoid arthritis (RA) is a multifaceted autoimmune disorder characterized by chronic inflammation and joint destruction. Recent research has elucidated the intricate interplay between gut microbiota and RA pathogenesis, underscoring the role of microbiota-derived metabolites as pivotal contributors to disease development and progression. The human gut microbiota, comprising a vast array of microorganisms and their metabolic byproducts, plays a crucial role in maintaining immune homeostasis. Dysbiosis of this microbial community has been linked to numerous autoimmune disorders, including RA. Microbiota-derived metabolites, such as short-chain fatty acids (SCFAs), tryptophan derivatives, Trimethylamine-N-oxide (TMAO), bile acids, peptidoglycan, and lipopolysaccharide (LPS), exhibit immunomodulatory properties that can either exacerbate or ameliorate inflammation in RA. Mechanistically, these metabolites influence immune cell differentiation, cytokine production, and gut barrier integrity, collectively shaping the autoimmune milieu. This review highlights recent advances in understanding the intricate crosstalk between microbiota metabolites and RA pathogenesis and also discusses the potential of specific metabolites to trigger or suppress autoimmunity, shedding light on their molecular interactions with immune cells and signaling pathways. Additionally, this review explores the translational aspects of microbiota metabolites as diagnostic and prognostic tools in RA. Furthermore, the challenges and prospects of translating these findings into clinical practice are critically examined.

Determining the emotional regulation function of Bifidobacterium breve: the role of gut metabolite regulation over colonization capability

Psychobiotics that modulate the gut-brain axis have emerged as promising interventions for clinical mental disorders. Bifidobacterium breve CCFM1025 has demonstrated antidepressant effects in both mice and patients with major depression. Nevertheless, the precise mechanism of action of CCFM1025 in emotional regulation remains ambiguous. This study aimed to explore the colonization capacity of CCFM1025 and its dose-dependent effect on emotional regulation in mice exposed to chronic unpredictable mild stress (CUMS). Additionally, we examined its regulatory effects on intestinal and serum metabolites in mice. The results revealed that CCFM1025 did not exhibit a heightened gut retention capability compared to the conspecific control strain. Nevertheless, CCFM1025 exhibited dose-dependent mitigation of anxiety-like behavior and memory impairment induced by CUMS, while also restoring gut microbiota homeostasis. Notably, CCFM1025 demonstrated a robust ability to exert potent gut metabolite regulation, resulting in significant elevation of bile acid and tryptophan metabolites in the gut contents and serum of mice. These findings indicate that the impact of CCFM1025 on emotional regulation may be attributed to its regulation of gut metabolites rather than its gut retention capability. The potential of Bifidobacterium to modulate bile acid metabolism may serve as a valuable avenue for regulating the gut microbiota and successfully exert emotion regulation.

Ephrin B3 exacerbates colitis and colitis-associated colorectal cancer

Ephrin B3, a member of Eph/ephrin family, contributes to embryogenesis and carcinogenesis, but few studies have suggested whether this ligand has regulatory effect on colitis. This study was to determine whether ephrin B3 played a role in colitis and colonic carcinogenesis. Dextran sodium sulfate (DSS)-induced colitis and azoxymethane (AOM)/DSS-induced colitis-associated carcinogenesis model was established in Efnb3-deficient (Efnb3-/-) mice. Label-free quantitative proteomics were performed to identify the Efnb3-regulated proteins. Our results showed that Efnb3 knock out reduced the symptoms of DSS-induced colitis, such as disease activity index (DAI), inflammatory factors release, and dysfunction of the intestinal barrier. Quantitative proteomics revealed that Efnb3 regulated 95 proteins which clustered in the platelet degranulation, response to elevated platelet cytosolic Ca2+, MAPK signaling for integrins such as ITGB4. Furthermore, ephrin B3 inactived ITGB4/AKT signal pathway and then promoted epithelial barrier dysfunction. Simultaneously, ephrin B3 promoted Gremlin-1/NF-κB signal pathway and thereby increased inflammatory factors release. In addition, the higher level of Efnb3 in colon cancer patients is correlated with worse survival. Efnb3-/- mice exhibited susceptibility to AOM/DSS-induced colorectal cancer. Our finding discovered that Efnb3 played an important role in the development of colitis and colitis-associated colorectal cancer. Efnb3 deficiency improved the intestinal barrier by ITGB4 and suppressed inflammation via Gremlin-1/NF-κB signal pathway, which may provide a novel therapeutic strategy for the treatment of colitis and colitis-associated colorectal cancer.

Novel approaches in IBD therapy: targeting the gut microbiota-bile acid axis

Inflammatory bowel disease (IBD) is a chronic and recurrent condition affecting the gastrointestinal tract. Disturbed gut microbiota and abnormal bile acid (BA) metabolism are notable in IBD, suggesting a bidirectional relationship. Specifically, the diversity of the gut microbiota influences BA composition, whereas altered BA profiles can disrupt the microbiota. IBD patients often exhibit increased primary bile acid and reduced secondary bile acid concentrations due to a diminished bacteria population essential for BA metabolism. This imbalance activates BA receptors, undermining intestinal integrity and immune function. Consequently, targeting the microbiota-BA axis may rectify these disturbances, offering symptomatic relief in IBD. Here, the interplay between gut microbiota and bile acids (BAs) is reviewed, with a particular focus on the role of gut microbiota in mediating bile acid biotransformation, and contributions of the gut microbiota-BA axis to IBD pathology to unveil potential novel therapeutic avenues for IBD.

Gut microbiome-associated predictors as biomarkers of response to advanced therapies in inflammatory bowel disease: a systematic review

Loss of response to therapy in inflammatory bowel disease (IBD) has led to a surge in research focusing on precision medicine. Three systematic reviews have been published investigating the associations between gut microbiota and disease activity or IBD therapy. We performed a systematic review to investigate the microbiome predictors of response to advanced therapy in IBD. Unlike previous studies, our review focused on predictors of response to therapy; so the included studies assessed microbiome predictors before the proposed time of response or remission. We also provide an update of the available data on mycobiomes and viromes. We highlight key themes in the literature that may serve as future biomarkers of treatment response: the abundance of fecal SCFA-producing bacteria and opportunistic bacteria, metabolic pathways related to butyrate synthesis, and non-butyrate metabolomic predictors, including bile acids (BAs), amino acids, and lipids, as well as mycobiome predictors of response.

Yujin powder improves large intestine dampness-heat syndrome by regulating gut microbiota and serum metabolism

Large intestine dampness-heat syndrome (LIDHS) is a common syndrome type in animal diarrheal diseases. Yujin powder (YJP) is one of the classic prescriptions for treating damp-heat diarrhea. The aim of this study was to investigate the regulatory effects of YJP on gut microbiota and serum metabolism in LIDHS rats using 16S rRNA sequencing and nontargeted metabolomics. The LIDHS rat model was induced through a high-sugar and high-fat diet, exposure to a high-temperature and high-humidity environment, and infection with Escherichia coli. The results demonstrated that the administration of YJP resulted in a decrease in the abundance of Desulfovibrio, Parabacteroides, Bacteroides, Allobaculum, Escherichia, Butyricimonas, Parasutterella, and Blautia and an increase in Ruminococcus, Akkermansia, Roseburia, and Lachnoclostridium. A total of 25 potential biomarkers were identified in three groups of rats. These metabolites were primarily involved in glycerophospholipid metabolism, taurine and hypotaurine metabolism, glycerol ester metabolism, arachidonic acid metabolism, primary bile acid synthesis, and tryptophan metabolism. Our study demonstrated that YJP has the potential to alleviate LIDHS by modulating gut microbial and serum metabolic homeostasis. These results establish a foundation and offer valuable guidance for the utilization of YJP in the treatment of LIDHS.

High-fructose corn syrup aggravates colitis via microbiota dysbiosis-mediated Th17/Treg imbalance

Dietary fructose is widely used in beverages, processed foods, and Western diets as food additives, and is closely related to the increased prevalence of multiple diseases, including inflammatory bowel disease (IBD). However, the detailed mechanism by which high fructose disrupts intestinal homeostasis remains elusive. The present study showed that high-fructose corn syrup (HFCS) administration exacerbated intestinal inflammation and deteriorated barrier integrity. Several in vivo experimental models were utilized to verify the importance of gut microbiota and immune cells in HFCS-mediated dextran sulfate sodium (DSS)-induced colitis. In addition, untargeted metabolomics analysis revealed the imbalance between primary bile acids (PBAs) and secondary bile acids (SBAs) in feces. Hence, high fructose was speculated to modulate gut microbiota community and reduced the relative abundance of Clostridium and Clostridium scindens at genus and species level respectively, followed by a decrease in SBAs, especially isoalloLCA, thereby affecting Th17/Treg cells equilibrium and promoting intestinal inflammation. These findings provide novel insights into the crosstalk between gut flora, bile acids, and mucosal immunity, and highlight potential strategies for precise treatment of IBD.

The mechanism of traditional medicine in alleviating ulcerative colitis: regulating intestinal barrier function

Ulcerative colitis (UC) is an idiopathic inflammatory disease mainly affects the large bowel and the rectum. The pathogenesis of this disease has not been fully elucidated, while the disruption of the intestinal barrier function triggered by various stimulating factors related to the host genetics, immunity, gut microbiota, and environment has been considered to be major mechanisms that affect the development of UC. Given the limited effective therapies, the treatment of this disease is not ideal and its incidence and prevalence are increasing. Therefore, developing new therapies with high efficiency and efficacy is important for treating UC. Many recent studies disclosed that numerous herbal decoctions and natural compounds derived from traditional herbal medicine showed promising therapeutic activities in animal models of colitis and have gained increasing attention from scientists in the study of UC. Some of these decoctions and compounds can effectively alleviate colonic inflammation and relieve clinical symptoms in animal models of colitis via regulating intestinal barrier function. While no study is available to review the underlying mechanisms of these potential therapies in regulating the integrity and function of the intestinal barrier. This review aims to summarize the effects of various herbal decoctions or bioactive compounds on the severity of colonic inflammation via various mechanisms, mainly including regulating the production of tight junction proteins, mucins, the composition of gut microbiota and microbial-associated metabolites, the infiltration of inflammatory cells and mediators, and the oxidative stress in the gut. On this basis, we discussed the related regulators and the affected signaling pathways of the mentioned traditional medicine in modulating the disruption or restoration of the intestinal barrier, such as NF-κB/MAPK, PI3K, and HIF-1α signaling pathways. In addition, the possible limitations of current studies and a prospect for future investigation and development of new UC therapies are provided based on our knowledge and current understanding. This review may improve our understanding of the current progression in studies of traditional medicine-derived therapies in protecting the intestinal barrier function and their roles in alleviating animal models of UC. It may be beneficial to the work of researchers in both basic and translational studies of UC.

Bile acids and their receptors: Potential therapeutic targets in inflammatory bowel disease

Chronic and recurrent inflammatory disorders of the gastrointestinal tract caused by a complex interplay between genetics and intestinal dysbiosis are called inflammatory bowel disease. As a result of the interaction between the liver and the gut microbiota, bile acids are an atypical class of steroids produced in mammals and traditionally known for their function in food absorption. With the development of genomics and metabolomics, more and more data suggest that the pathophysiological mechanisms of inflammatory bowel disease are regulated by bile acids and their receptors. Bile acids operate as signalling molecules by activating a variety of bile acid receptors that impact intestinal flora, epithelial barrier function, and intestinal immunology. Inflammatory bowel disease can be treated in new ways by using these potential molecules. This paper mainly discusses the increasing function of bile acids and their receptors in inflammatory bowel disease and their prospective therapeutic applications. In addition, we explore bile acid metabolism and the interaction of bile acids and the gut microbiota.

Probiotics for the treatment of ulcerative colitis: a review of experimental research from 2018 to 2022

Ulcerative colitis (UC) has become a worldwide public health problem, and the prevalence of the disease among children has been increasing. The pathogenesis of UC has not been elucidated, but dysbiosis of the gut microbiota is considered the main cause of chronic intestinal inflammation. This review focuses on the therapeutic effects of probiotics on UC and the potential mechanisms involved. In animal studies, probiotics have been shown to alleviate symptoms of UC, including weight loss, diarrhea, blood in the stool, and a shortened colon length, while also restoring intestinal microecological homeostasis, improving gut barrier function, modulating the intestinal immune response, and attenuating intestinal inflammation, thereby providing theoretical support for the development of probiotic-based microbial products as an adjunctive therapy for UC. However, the efficacy of probiotics is influenced by factors such as the bacterial strain, dose, and form. Hence, the mechanisms of action need to be investigated further. Relevant clinical trials are currently lacking, so the extension of animal experimental findings to clinical application requires a longer period of consideration for validation.

Manipulating Microbiota in Inflammatory Bowel Disease Treatment: Clinical and Natural Product Interventions Explored

Inflammatory bowel disease (IBD) is a complex multifactorial chronic inflammatory disease, that includes Crohn's disease (CD) and ulcerative colitis (UC), having progressively increasing global incidence. Disturbed intestinal flora has been highlighted as an important feature of IBD and offers promising strategies for IBD remedies. A brief overview of the variations occurring in intestinal flora during IBD is presented, and the role of the gut microbiota in intestinal barrier maintenance, immune and metabolic regulation, and the absorption and supply of nutrients is reviewed. More importantly, we review drug research on gut microbiota in the past ten years, including research on clinical and natural drugs, as well as adjuvant therapies, such as Fecal Microbiota Transplantation and probiotic supplements. We also summarize the interventions and mechanisms of these drugs on gut microbiota.

Crosstalk between Gut Microbiota and Host Immunity: Impact on Inflammation and Immunotherapy

Gut microbes and their metabolites are actively involved in the development and regulation of host immunity, which can influence disease susceptibility. Herein, we review the most recent research advancements in the gut microbiota-immune axis. We discuss in detail how the gut microbiota is a tipping point for neonatal immune development as indicated by newly uncovered phenomenon, such as maternal imprinting, in utero intestinal metabolome, and weaning reaction. We describe how the gut microbiota shapes both innate and adaptive immunity with emphasis on the metabolites short-chain fatty acids and secondary bile acids. We also comprehensively delineate how disruption in the microbiota-immune axis results in immune-mediated diseases, such as gastrointestinal infections, inflammatory bowel diseases, cardiometabolic disorders (e.g., cardiovascular diseases, diabetes, and hypertension), autoimmunity (e.g., rheumatoid arthritis), hypersensitivity (e.g., asthma and allergies), psychological disorders (e.g., anxiety), and cancer (e.g., colorectal and hepatic). We further encompass the role of fecal microbiota transplantation, probiotics, prebiotics, and dietary polyphenols in reshaping the gut microbiota and their therapeutic potential. Continuing, we examine how the gut microbiota modulates immune therapies, including immune checkpoint inhibitors, JAK inhibitors, and anti-TNF therapies. We lastly mention the current challenges in metagenomics, germ-free models, and microbiota recapitulation to a achieve fundamental understanding for how gut microbiota regulates immunity. Altogether, this review proposes improving immunotherapy efficacy from the perspective of microbiome-targeted interventions.

Exclusive Enteral Nutrition Exerts Anti-Inflammatory Effects through Modulating Microbiota, Bile Acid Metabolism, and Immune Activities

Exclusive enteral nutrition (EEN) can induce remission in patients with pediatric Crohn’s disease (CD). This study aims to depict EEN’s modification of bile acid (BA) metabolism in pediatric CD and explores the effect of the EEN-enriched BA in inhibiting the inflammatory response. The twelve enrolled pediatric CD patients showed BA dysmetabolism, represented by decreased levels of fecal secondary and unconjugated BAs as determined by UPLC–TQMS, which were accompanied by gut microbiota dysbiosis and reduced BA-metabolizing bacteria including Eubacterium and Ruminococcus genera, assessed by shotgun metagenomic sequencing. EEN treatment induced remission in these patients at eight weeks, and nine patients remained in stable remission for longer than 48 weeks. EEN improved BA dysmetabolism, with some enriched BAs, including hyocholic acid (HCA), α-muricholic acid (αMCA), strongly associated with decreased severity of CD symptoms. These BAs were significantly correlated with the increased abundance of certain bacteria, including Clostridium innocuum and Hungatella hathewayi, which express 3β-hydroxysteroid dehydrogenase and 5β-reductase. HCA could suppress TNF-α production by CD4+ T cells in the peripheral blood mononuclear cells (PBMCs) of CD patients. Moreover, intraperitoneal injection of HCA could attenuate dextran sulfate sodium (DSS)-induced mouse colitis. Our data suggests that BA modification may contribute to the EEN-induced remission of pediatric CD.

The bridge of the gut–joint axis: Gut microbial metabolites in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by joint destruction, synovitis, and pannus formation. Gut microbiota dysbiosis may exert direct pathogenic effects on gut homeostasis. It may trigger the host’s innate immune system and activate the “gut–joint axis”, which exacerbates the RA. However, although the importance of the gut microbiota in the development and progression of RA is widely recognized, the mechanisms regulating the interactions between the gut microbiota and the host immune system remain incompletely defined. In this review, we discuss the role of gut microbiota-derived biological mediators, such as short-chain fatty acids, bile acids, and tryptophan metabolites, in maintaining intestinal barrier integrity, immune balance and bone destruction in RA patients as the bridge of the gut–joint axis.