Ursodeoxycholic acid and lithocholic acid exert anti-inflammatory actions in the colon

Ethnobotany and phytochemistry of plants used to treat musculoskeletal disorders among Skaw Karen, Thailand

CONTEXT

Musculoskeletal system disorders (MSD) are prevalent around the world affecting the health of people, especially farmers who work hard in the field. Karen farmers use many medicinal plants to treat MSD.

OBJECTIVE

This study collects traditional plant-based remedies used by the Skaw Karen to treat MSD and evaluates their active phytochemical compounds.

MATERIALS AND METHODS

The ethnobotanical study was conducted in six Karen villages in Chiang Mai province using semi-structured interviews were of 120 informants. The data were analyzed using ethnobotanical indices including use values (UV), choice value (CV), and informant consensus factor (ICF). Consequently, the 20 most important species, according to the indices, were selected for phytochemical analysis using LC-MS/MS.

RESULTS

A total of 3731 use reports were obtained for 139 species used in MSD treatment. The most common ailments treated with those plants were muscular pain. A total of 172 high-potential active compounds for MSD treatment were identified. Most of them were flavonoids, terpenoids, alkaloids, and steroids. The prevalent phytochemical compounds related to treat MSD were 9-hydroxycalabaxanthone, dihydrovaltrate, morroniside, isoacteoside, lithocholic acid, pomiferin, cucurbitacin E, leonuriside A, liriodendrin, and physalin E. Sambucus javanica Reinw. ex Blume (Adoxaceae), Betula alnoides Buch.-Ham. ex D.Don (Betulaceae), Blumea balsamifera (L.) DC. (Asteraceae), Plantago major L. (Plantaginaceae) and Flacourtia jangomas (Lour.) Raeusch. (Salicaceae) all had high ethnobotanical index values and many active compounds.

DISCUSSION AND CONCLUSIONS

This study provides valuable information, demonstrating low-cost medicine plants that are locally available. It is a choice of treatment for people living in remote areas.

Polymer-Based Nanoparticles with Probucol and Lithocholic Acid: A Novel Therapeutic Approach for Oxidative Stress-Induced Retinopathies

Oxidative stress is pivotal in retinal disease progression, causing dysfunction in various retinal components. An effective antioxidant, such as probucol (PB), is vital to counteract oxidative stress and emerges as a potential candidate for treating retinal degeneration. However, the challenges associated with delivering lipophilic drugs such as PB to the posterior segment of the eye, specifically targeting photoreceptor cells, necessitate innovative solutions. This study uses formulation-based spray dry encapsulation technology to develop polymer-based PB-lithocholic acid (LCA) nanoparticles and assesses their efficacy in the 661W photoreceptor-like cell line. Incorporating LCA enhances nanoparticles' biological efficacy without compromising PB stability. In vitro studies demonstrate that PB-LCA nanoparticles prevent reactive oxygen species (ROS)-induced oxidative stress by improving cellular viability through the nuclear erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. These findings propose PB-LCA nanoparticles as a promising therapeutic strategy for oxidative stress-induced retinopathies.

Insights into the gut-kidney axis and implications for chronic kidney disease management in cats and dogs

Chronic kidney disease (CKD) in cats and dogs presents significant clinical challenges, with emerging research highlighting the pivotal role of the gut-kidney axis in its pathogenesis and management. Gut dysbiosis, characterized by alterations in the gut microbiome composition and function, contributes to microbial dysmetabolism of key nutrients causing uremic toxin accumulation and disruptions in amino acid, bile acid and fatty acid profiles. These disturbances in turn exacerbate renal dysfunction and systemic inflammation. Recent research in veterinary medicine, particularly in cats, supports the gut microbiome and microbial-derived metabolites as novel therapeutic targets. Potential therapeutic strategies targeting the gut microbiome and microbial dysmetabolism, including dietary management, probiotics, adsorbents, and addressing constipation, offer promising avenues for intervention to restore metabolic balance and preserve renal function. This review highlights the microbial influence on renal health and focuses on potential therapeutic strategies available to veterinarians to optimize the management of CKD in cats and dogs.

Recent developments and new directions in the use of natural products for the treatment of inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) represents a significant global health challenge, and there is an urgent need to explore novel therapeutic interventions. Natural products have demonstrated highly promising effectiveness in the treatment of IBD.

PURPOSE

This study systematically reviews the latest research advancements in leveraging natural products for IBD treatment.

METHODS

This manuscript strictly adheres to the PRISMA guidelines. Relevant literature on the effects of natural products on IBD was retrieved from the PubMed, Web of Science and Cochrane Library databases using the search terms "natural product," "inflammatory bowel disease," "colitis," "metagenomics", "target identification", "drug delivery systems", "polyphenols," "alkaloids," "terpenoids," and so on. The retrieved data were then systematically summarized and reviewed.

RESULTS

This review assessed the different effects of various natural products, such as polyphenols, alkaloids, terpenoids, quinones, and others, in the treatment of IBD. While these natural products offer promising avenues for IBD management, they also face challenges in terms of clinical translation and drug discovery. The advent of metagenomics, single-cell sequencing, target identification techniques, drug delivery systems, and other cutting-edge technologies heralds a new era in overcoming these challenges.

CONCLUSION

This paper provides an overview of current research progress in utilizing natural products for the treatment of IBD, exploring how contemporary technological innovations can aid in discovering and harnessing bioactive natural products for the treatment of IBD.

Multi-omics Analysis of a Fecal Microbiota Transplantation Trial Identifies Novel Aspects of Acute GVHD Pathogenesis

Acute GVHD (aGVHD) is a major complication of allogeneic hematopoietic cell transplantation (alloHCT) associated with gut microbiota disruptions. However, whether therapeutic microbiota modulation prevents aGVHD is unknown. We conducted a randomized, placebo-controlled trial of third-party fecal microbiota transplantation (FMT) administered at the peak of microbiota injury in 100 patients with acute myeloid leukemia receiving induction chemotherapy and alloHCT recipients. Despite improvements in microbiome diversity, expansion of commensals, and shrinkage of potential pathogens, aGVHD occurred more frequently after FMT than placebo. Although this unexpected finding could be explained by clinical differences between the two arms, we asked whether a microbiota explanation might be also present. To this end, we performed multi-omics analysis of preintervention and postintervention gut microbiome and serum metabolome. We found that postintervention expansion of Faecalibacterium, a commensal genus with gut-protective and anti-inflammatory properties under homeostatic conditions, predicted a higher risk for aGVHD. Faecalibacterium expansion occurred predominantly after FMT and was due to engraftment of unique donor taxa, suggesting that donor Faecalibacterium-derived antigens might have stimulated allogeneic immune cells. Faecalibacterium and ursodeoxycholic acid (an anti-inflammatory secondary bile acid) were negatively correlated, offering an alternative mechanistic explanation. In conclusion, we demonstrate context dependence of microbiota effects where a normally beneficial bacteria may become detrimental in disease. While FMT is a broad, community-level intervention, it may need precision engineering in ecologically complex settings where multiple perturbations (e.g., antibiotics, intestinal damage, alloimmunity) are concurrently in effect.

SIGNIFICANCE

Post-FMT expansion of Faecalibacterium, associated with donor microbiota engraftment, predicted a higher risk for aGVHD in alloHCT recipients. Although Faecalibacterium is a commensal genus with gut-protective and anti-inflammatory properties under homeostatic conditions, our findings suggest that it may become pathogenic in the setting of FMT after alloHCT. Our results support a future trial with precision engineering of the FMT product used as GVHD prophylaxis after alloHCT.

Prevalence of Apical Periodontitis in Patients with Autoimmune Liver Diseases on Immune Suppressants and Immune Modulators: A Cross-sectional Study

INTRODUCTION

Autoimmune liver diseases (ALDs) are chronic conditions generated by an immune-mediated autoaggressive inflammatory reaction in genetically susceptible individuals. The purpose of this study was to evaluate the prevalence of apical periodontitis (AP) in patients suffering from ALDs undergoing treatment with the immune suppressants glucocorticoids, azathioprine, and/or ursodeoxycholic acid.

METHODS

The ALD group included 46 patients (11 men and 35 women, average age = 57.9 ± 11.8 years) and 1186 teeth. The control group included 50 healthy patients not taking any medications (15 men and 35 women, average age = 58.6 ± 10.4 years) and 1251 teeth. Demographic data and medical, pharmacologic, and dental history were recorded. Dental and radiographic examinations were performed. The presence of AP; the periapical index score; decayed, missing, and filled teeth; quality of restoration, and root canal treatment were evaluated. The influence of the medications the patients were taking on the prevalence of AP was also tested.

RESULTS

The prevalence of AP was significantly lower in ALDs than in the control group at the patient (P = .019) and tooth level (P = .014). Smoking and age were associated with a significant increase in AP in cases and controls (P = .045 and P = .001, respectively). In both groups, endodontically treated teeth showed a higher prevalence of AP.

CONCLUSIONS

Considering the limitations because of the observational nature of the study, the patients affected by ALDs liver diseases and undergoing treatment with immune suppressors (often associated with immune modulators) were found to exhibit a lower prevalence of AP.

Gut microbiota and metabolites as predictors of biologics response in inflammatory bowel disease: A comprehensive systematic review

Nonresponse to biologic agents in patients with inflammatory bowel disease (IBD) poses a significant public health burden, and the prediction of response to biologics offers valuable insights for IBD management. Given the pivotal role of gut microbiota and their endogenous metabolites in IBD, we conducted a systematic review to investigate the potential of fecal microbiota and mucosal microbiota and endogenous metabolomic markers as predictors for biotherapy response in IBD patients. A total of 38 studies were included in the review. Following anti-TNF-α treatment, the bacterial community characteristics of IBD patients exhibited a tendency to resemble those observed in healthy controls, indicating an improved clinical response. The levels of endogenous metabolites butyrate and deoxycholic acid were significantly associated with clinical remission following anti-TNF-α therapy. IBD patients who responded well to vedolizumab treatment had higher levels of specific bacteria that produce butyrate, along with increased levels of metabolites such as butyrate, branched-chain amino acids and acetamide following vedolizumab treatment. Crohn's disease patients who responded positively to ustekinumab treatment showed higher levels of Faecalibacterium and lower levels of Escherichia/Shigella. In conclusion, fecal microbiota and mucosal microbiota as well as their endogenous metabolites could provide a predictive tool for assessing the response of IBD patients to various biological agents and serve as a valuable reference for precise drug selection in clinical IBD patients.

Bile acid metabolism and signaling in health and disease: molecular mechanisms and therapeutic targets

Bile acids, once considered mere dietary surfactants, now emerge as critical modulators of macronutrient (lipid, carbohydrate, protein) metabolism and the systemic pro-inflammatory/anti-inflammatory balance. Bile acid metabolism and signaling pathways play a crucial role in protecting against, or if aberrant, inducing cardiometabolic, inflammatory, and neoplastic conditions, strongly influencing health and disease. No curative treatment exists for any bile acid influenced disease, while the most promising and well-developed bile acid therapeutic was recently rejected by the FDA. Here, we provide a bottom-up approach on bile acids, mechanistically explaining their biochemistry, physiology, and pharmacology at canonical and non-canonical receptors. Using this mechanistic model of bile acids, we explain how abnormal bile acid physiology drives disease pathogenesis, emphasizing how ceramide synthesis may serve as a unifying pathogenic feature for cardiometabolic diseases. We provide an in-depth summary on pre-existing bile acid receptor modulators, explain their shortcomings, and propose solutions for how they may be remedied. Lastly, we rationalize novel targets for further translational drug discovery and provide future perspectives. Rather than dismissing bile acid therapeutics due to recent setbacks, we believe that there is immense clinical potential and a high likelihood for the future success of bile acid therapeutics.

Host-gut microbiota derived secondary metabolite mediated regulation of Wnt/β-catenin pathway: a potential therapeutic axis in IBD and CRC

The intestinal tract encompasses one of the largest mucosal surfaces with a well-structured layer of intestinal epithelial cells supported by a network of underlying lamina propria immune cells maintaining barrier integrity. The commensal microflora in this environment is a major contributor to such functional outcomes due to its prominent role in the production of secondary metabolites. Of the several known metabolites of gut microbial origin, such as Short Chain Fatty Acids (SCFAs), amino acid derivatives, etc., secondary bile acids (BAs) are also shown to exhibit pleiotropic effects maintaining gut homeostasis in addition to their canonical role in dietary lipid digestion. However, dysbiosis in the intestine causes an imbalance in microbial diversity, resulting in alterations in the functionally effective concentration of these secondary metabolites, including BAs. This often leads to aberrant activation of the underlying lamina propria immune cells and associated signaling pathways, causing intestinal inflammation. Sustained activation of these signaling pathways drives unregulated cell proliferation and, when coupled with genotoxic stress, promotes tumorigenesis. Here, we aimed to discuss the role of secondary metabolites along with BAs in maintaining immune-gut homeostasis and regulation of inflammation-driven tumorigenesis with emphasis on the classical Wnt/β-Catenin signaling pathway in colon cancer.

Ursodeoxycholic and chenodeoxycholic bile acids attenuate systemic and liver inflammation induced by lipopolysaccharide in rats

Bacterial lipopolysaccharide (LPS) induces general inflammation, by activating pathways involving cytokine production, blood coagulation, complement system activation, and acute phase protein release. The key cellular players are leukocytes and endothelial cells, that lead to tissue injury and organ failure. The aim of this study was to explore the anti-inflammatory, antioxidant, and cytoprotective properties of two bile acids, ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) in LPS-induced endotoxemia in rats. The experiment involved six distinct groups of Wistar rats, each subjected to different pretreatment conditions: control and LPS groups were pretreated with propylene glycol, as a bile acid solvent, while the other groups were pretreated with UDCA or CDCA for 10 days followed by an LPS injection on day 10. The results showed that both UDCA and CDCA reduced the production of pro-inflammatory cytokines: TNF-α, GM-CSF, IL-2, IFNγ, IL-6, and IL-1β and expression of nuclear factor-κB (NF-κB) induced by LPS. In addition, pretreatment with these bile acids showed a positive impact on lipid profiles, a decrease in ICAM levels, an increase in antioxidant activity (SOD, |CAT, GSH), and a decrease in prooxidant markers (H2O2 and O2-). Furthermore, both bile acids alleviated LPS-induced liver injury. While UDCA and CDCA pretreatment attenuated homocysteine levels in LPS-treated rats, only UDCA pretreatment showed reductions in other serum biochemical markers, including creatine kinase, lactate dehydrogenase, and high-sensitivity troponin I. It can be concluded that both, UDCA and CDCA, although exerted slightly different effects, can prevent the inflammatory responses induced by LPS, improve oxidative stress status, and attenuate LPS-induced liver injury.

Deciphering the nutritional strategies for polysaccharides effects on intestinal barrier in broilers: Selectively promote microbial ecosystems

The gut microbiota, a complex and dynamic microbial ecosystem, plays a crucial role in regulating the intestinal barrier. Polysaccharide foraging is specifically dedicated to establishing and maintaining microbial communities, contributing to the shaping of the intestinal ecosystem and ultimately enhancing the integrity of the intestinal barrier. The utilization and regulation of individual polysaccharides often rely on distinct gut-colonizing bacteria. The products of their metabolism not only benefit the formation of the ecosystem but also facilitate cross-feeding partnerships. In this review, we elucidate the mechanisms by which specific bacteria degrade polysaccharides, and how polysaccharide metabolism shapes the microbial ecosystem through cross-feeding. Furthermore, we explore how selectively promoting microbial ecosystems and their metabolites contributes to improvements in the integrity of the intestinal barrier.

Enhanced mucosal mitochondrial function corrects dysbiosis and OXPHOS metabolism in IBD

Background

Mitochondrial (Mito) dysfunction in IBD reduces mucosal O2 consumption and increases O2 delivery to the microbiome. Increased enteric O2 promotes blooms of facultative anaerobes (eg. Proteobacteria ) and restricts obligate anaerobes (eg. Firmicutes ). Dysbiotic metabolites negatively affect host metabolism and immunity. Our novel compound (AuPhos) upregulates intestinal epithelial cell (IEC) mito function, attenuates colitis and corrects dysbiosis in humanized Il10-/- mice. We posit that AuPhos corrects IBD-associated dysbiotic metabolism.

Methods

Primary effect of AuPhos on mucosal Mito respiration and healing process was studied in ex vivo treated human colonic biopsies and piroxicam-accelerated (Px) Il10-/- mice. Secondary effect on microbiome was tested in DSS-colitis WT B6 and germ-free 129.SvEv WT or Il10-/- mice reconstituted with human IBD stool (Hu- Il10-/- ). Mice were treated orally with AuPhos (10- or 25- mg/kg; q3d) or vehicle, stool samples collected for fecal lipocalin-2 (f-LCN2) assay and microbiome analyses using 16S rRNA sequencing. AuPhos effect on microbial metabolites was determined using untargeted global metabolomics. AuPhos-induced hypoxia in IECs was assessed by Hypoxyprobe-1 staining in sections from pimonidazole HCl-infused DSS-mice. Effect of AuPhos on enteric oxygenation was assessed by E. coli Nissle 1917 WT (aerobic respiration-proficient) and cytochrome oxidase (cydA) mutant (aerobic respiration-deficient).

Results

Metagenomic (16S) analysis revealed AuPhos reduced relative abundances of Proteobacteria and increased blooms of Firmicutes in uninflamed B6 WT, DSS-colitis, Hu-WT and Hu- Il10-/- mice. AuPhos also increased hypoxyprobe-1 staining in surface IECs suggesting enhanced O2 utilization. AuPhos-induced anaerobiosis was confirmed by a significant increase in cydA mutant compared to WT (O2-utlizing) E.coli . Ex vivo treatment of human biopsies with AuPhos showed significant increase in Mito mass, and complexes I and IV. Further, gene expression analysis of AuPhos-treated biopsies showed increase in stem cell markers (Lgr4, Lgr5, Lrig1), with concomitant decreases in pro-inflammatory markers (IL1β,MCP1, RankL). Histological investigation of AuPhos-fed Px- Il10-/- mice showed significantly decreased colitis score in AuPhos-treated Px- Il10-/- mice, with decrease in mRNA of pro-inflammatory cytokines and increase in Mito complexes ( ND5 , ATP6 ). AuPhos significantly altered microbial metabolites associated with SCFA synthesis, FAO, TCA cycle, tryptophan and polyamine biosynthesis pathways. AuPhos increased pyruvate, 4-hydroxybutyrate, 2-hydroxyglutarate and succinate, suggesting an upregulation of pyruvate and glutarate pathways of butyrate production. AuPhos reduced IBD-associated primary bile acids (BA) with concomitant increase in secondary BA (SBA). AuPhos treatment significantly decreased acylcarnitines and increased L-carnitine reflective of enhanced FAO. AuPhos increases TCA cycle intermediates and creatine, energy reservoir substrates indicating enhanced OxPHOS. Besides, AuPhos also upregulates tryptophan metabolism, decreases Kynurenine and its derivatives, and increases polyamine biosynthesis pathway (Putresceine and Spermine).

Conclusion

These findings indicate that AuPhos-enhanced IEC mitochondrial function reduces enteric O2 delivery, which corrects disease-associated metabolomics by restoring short-chain fatty acids, SBA, AA and IEC energy metabolism.

Graphical abstract

Lithocholic Acid Alleviates Deoxynivalenol-Induced Inflammation and Oxidative Stress via PPARγ-Mediated Epigenetically Transcriptional Reprogramming in Porcine Intestinal Epithelial Cells

Deoxynivalenol (DON) is a common mycotoxin that induces intestinal inflammation and oxidative damage in humans and animals. Given that lithocholic acid (LCA) has been suggested to inhibit intestinal inflammation, we aimed to investigate the protective effects of LCA on DON-exposed porcine intestinal epithelial IPI-2I cells and the underlying mechanisms. Indeed, LCA rescued DON-induced cell death in IPI-2I cells and reduced DON-stimulated inflammatory cytokine levels and oxidative stress. Importantly, the nuclear receptor PPARγ was identified as a key transcriptional factor involved in the DON-induced inflammation and oxidative stress processes in IPI-2I cells. The PPARγ function was found compromised, likely due to the hyperphosphorylation of the p38 and ERK signaling pathways. In contrast, the DON-induced inflammatory responses and oxidative stress were restrained by LCA via PPARγ-mediated reprogramming of the core inflammatory and antioxidant genes. Notably, the PPARγ-modulated transcriptional regulations could be attributed to the altered recruitments of coactivator SRC-1/3 and corepressor NCOR1/2, along with the modified histone marks H3K27ac and H3K18la. This study emphasizes the protective actions of LCA on DON-induced inflammatory damage and oxidative stress in intestinal epithelial cells via PPARγ-mediated epigenetically transcriptional reprogramming, including histone acetylation and lactylation.

Microbial bile acid metabolite ameliorates mycophenolate mofetil-induced gastrointestinal toxicity through vitamin D3 receptor

Mycophenolate mofetil (MMF) is one of the most used immunosuppressive drugs in organ transplantation, but frequent gastrointestinal (GI) side effects through unknown mechanisms limit its clinical use. Gut microbiota and its metabolites were recently reported to play a vital role in MMF-induced GI toxicity, but the specific mechanism of how they interact with the human body is still unclear. Here, we found that secondary bile acids (BAs), as bacterial metabolites, were significantly reduced by MMF administration in the gut of mice. Microbiome data and fecal microbiota transfer model supported a microbiota-dependent effect on the reduction of secondary BAs. Supplementation of the secondary BA lithocholic acid alleviated MMF-induced weight loss, colonic inflammation, and oxidative phosphorylation damage. Genetic deletion of the vitamin D3 receptor (VDR), which serves as a primary colonic BA receptor, in colonic epithelial cells (VDRΔIEC) abolished the therapeutic effect of lithocholic acid on MMF-induced GI toxicity. Impressively, we discovered that paricalcitol, a Food and Drug Administration-approved VDR agonist that has been used in clinics for years, could effectively alleviate MMF-induced GI toxicity. Our study reveals a previously unrecognized mechanism of gut microbiota, BAs, and VDR signaling in MMF-induced GI side effects, offering potential therapeutic strategies for clinics.

Bile Acid Metabolic Profiles and Their Correlation with Intestinal Epithelial Cell Proliferation and Barrier Integrity in Suckling Piglets

Bile acids (BAs) are crucial for maintaining intestinal epithelial homeostasis. However, the metabolic changes in BAs and the communication between intestinal epithelial cells (IECs) in infants after birth remain unclear. This study aims to elucidate the BA profiles of newborn piglets (NPs) and suckling piglets (SPs), and to investigate their regulatory effects on IEC proliferation and barrier integrity, as well as the potential underlying mechanisms. In this study, compared with NPs, there were significant increases in serum triglycerides, total cholesterol, glucose, and albumin levels for SPs. The total serum BA content in SPs exhibited an obvious increase. Moreover, the expression of BA synthase cytochrome P450 27A1 (CYP27A1) was increased, and the ileal BA receptor Takeda G-coupled protein receptor 5 (TGR5) and proliferation marker Ki-67 were upregulated and showed a strong positive correlation through a Spearman correlation analysis, whereas the expression of farnesoid X receptor (FXR) and occludin was markedly downregulated in SPs and also revealed a strong positive correlation. These findings indicate that the increased synthesis and metabolism of BAs may upregulate TGR5 and downregulate FXR to promote IEC proliferation and influence barrier function; this offers a fresh perspective and evidence for the role of BAs and BA receptors in regulating intestinal development in neonatal pigs.

Lactobacillus acidophilus and its metabolite ursodeoxycholic acid ameliorate ulcerative colitis by promoting Treg differentiation and inhibiting M1 macrophage polarization

Lactobacillus acidophilus (LA) is a common clinical probiotic that improves ulcerative colitis (UC) by restoring intestinal immune balance. However, the interaction of LA with the gut microbiota and its metabolites in the treatment of UC remains unknown. Therefore, this study seeks to elucidate whether the gut microbiota and its metabolites act as pivotal effectors in LA's therapeutic mechanisms and how precisely they modulate intestinal immunity. In this study, we verified that LA can obviously ameliorate the disease severity, and regulate intestinal immune disorders in UC mice. Subsequently, antibiotic (ABX)-mediated depletion of the gut microflora demonstrated that the therapeutic efficiency of LA was closely associated with gut microbiota. In addition, the results of metabolomics revealed that ursodeoxycholic acid (UDCA), a metabolite of intestinal flora, may be a potential effector molecule mediating therapeutic effects of LA. Indeed, we found that UDCA can improve the macro pathological characteristics of UC mice, and through a comprehensive set of in vivo and in vitro experiments, we discovered that UDCA exerts dual effects on immune regulation. Firstly, it promotes the differentiation of Treg cells, resulting in increased secretion of anti-inflammatory cytokines. Secondly, UDCA inhibits the polarization of M1 macrophages, effectively reducing the secretion of pro-inflammatory cytokines. Moreover, we found that UDCA regulation of immune response is directly related to the RapGap/PI3K-AKT/NF-κB signaling pathway. In conclusion, LA and its metabolite, UDCA, may treat UC by activating the RapGap/PI3K-AKT/NF-κB signaling pathway and modulating Treg cells and M1 macrophages. All in all, our findings highlight the potential of microbial metabolites in enhancing probiotic for UC treatment.

Temporal Variability of the Dominant Fecal Microbiota in Healthy Adult Cats

While shifts in gut microbiota have been studied in diseased states, the temporal variability of the microbiome in cats has not been widely studied. This study investigated the temporal variability of the feline dysbiosis index (DI) and the abundance of core bacterial groups in healthy adult cats. The secondary aim was to evaluate the relationship between the fecal abundance of Clostridium hiranonis and the fecal concentrations of unconjugated bile acids. A total of 142 fecal samples collected from 17 healthy cats were prospectively included: nine cats with weekly collection over 3 weeks (at least four time points), five cats with monthly collection over 2 months (three time points), and three cats with additional collections for up to 10 months. The DI remained stable within the reference intervals over two months for all cats (Friedman test, p > 0.2), and 100% of the DI values (n = 142) collected throughout the study period remained within the RI. While some temporal individual variation was observed for individual taxa, the magnitude was minimal compared to cats with chronic enteropathy and antibiotic exposure. Additionally, the abundance of Clostridium hiranonis was significantly correlated with the percentage of fecal primary bile acids, supporting its role as a bile acid converter in cats.

Rumen microbiome-driven insight into bile acid metabolism and host metabolic regulation

Gut microbes play a crucial role in transforming primary bile acids (BAs) into secondary forms, which influence systemic metabolic processes. The rumen, a distinctive and critical microbial habitat in ruminants, boasts a diverse array of microbial species with multifaceted metabolic capabilities. There remains a gap in our understanding of BA metabolism within this ecosystem. Herein, through the analysis of 9371 metagenome-assembled genomes and 329 cultured organisms from the rumen, we identified two enzymes integral to BA metabolism: 3-dehydro-bile acid delta4,6-reductase (baiN) and the bile acid:Na + symporter family (BASS). Both in vitro and in vivo experiments were employed by introducing exogenous BAs. We revealed a transformation of BAs in rumen and found an enzyme cluster, including L-ribulose-5-phosphate 3-epimerase and dihydroorotate dehydrogenase. This cluster, distinct from the previously known BA-inducible operon responsible for 7α-dehydroxylation, suggests a previously unrecognized pathway potentially converting primary BAs into secondary BAs. Moreover, our in vivo experiments indicated that microbial BA administration in the rumen can modulate amino acid and lipid metabolism, with systemic impacts underscored by core secondary BAs and their metabolites. Our study provides insights into the rumen microbiome's role in BA metabolism, revealing a complex microbial pathway for BA biotransformation and its subsequent effect on host metabolic pathways, including those for glucose, amino acids, and lipids. This research not only advances our understanding of microbial BA metabolism but also underscores its wider implications for metabolic regulation, offering opportunities for improving animal and potentially human health.

Restrictive diets have a beneficial impact on dextran sodium sulfate-induced colitis in male mice

BACKGROUND

Previously, we assessed the impact of restrictive diets, including caloric restriction (CR), intermittent fasting (IF), or fasting-mimicking diet (FMD), on a healthy gastrointestinal tract. We revealed that each of the diets shows anti-inflammatory outcomes.

OBJECTIVE

The current study aimed to verify the diets' applicability in treating colitis.

METHODS

We exposed a mouse model with mild chronic dextran sodium sulfate (DSS)-induced colitis to ad libitum control feeding, CR, IF, or FMD. The collected samples were analyzed for markers of inflammation.

RESULTS

The diets reduced DSS-triggered increases in spleen weight and myeloperoxidase (MPO) activity. Diet intervention also influenced occludin levels, small intestine morphology, as well as cytokine and inflammatory gene expression, mainly in the mucosa of the proximal colon. The diets did not reverse DSS-enhanced gut permeability and thickening of the colon muscularis externa. Concerning inflammatory gene expression, the impact of DSS and the dietary intervention was limited to the colon as we did not measure major changes in the jejunum mucosa, Peyer's patches, and mesenteric lymph nodes. Further, rather modest changes in the concentration of intestinal bile acids were observed in response to the diets, whereas taurine and its conjugates levels were strongly affected.

CONCLUSIONS

Despite the differences in the dietary protocol, the tested diets showed very similar impacts and, therefore, may be interchangeable when aiming to reduce inflammation in the colon. However, FMD showed the most consistent beneficial impact.

Synergistic effect of Euphorbia kansui stir-fried with vinegar and bile acids on malignant ascites effusion through modulation of gut microbiota

Background: Toxic Euphorbia kansui (EK) is employed to treat malignant ascites effusion (MAE). EK stir-fried with vinegar (VEK) has been demonstrated to reduce toxicity due to its preserved water-expelling effect. This was demonstrated to be correlated with gut microbiota. Therein, bile acids (BAs) have a bidirectional relationship with the gut microbiota. Therefore, the aim of this study is to explore whether BA-mediated gut microbiota influences the water-expelling effect of VEK against MAE. Methods: The MAE rat model was established by intraperitoneal injection of Walker-256 tumor cells. A reliable simultaneous method for the determination of 15 bile acids in rat feces using ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established and applied to analyze the fecal BAs in rats treated with VEK. The screened BA was then administered to VEK-treated MAE rats. The water-expelling effect was evaluated using histopathological analysis, biochemical examination, inflammatory factors in ascites, urine volume, ascites amount, and intestinal aquaporin expression. The microbial composition was determined using 16S rRNA sequencing, and the contents of bile acids were finally measured. Results: VEK decreased the content of fecal deoxycholic acid (DCA), lithocholic acid (LCA), and taurocholic acid (TCA) while increasing the content of ursodeoxycholic acid (UDCA). VEK alleviated liver, stomach, and intestinal injuries; oxidative damage; and inflammation, which were further ameliorated with UDCA intervention. VEK alleviated MAE by increasing the fecal water content, urine volume, and AQP3 protein expression and decreasing the urine levels of Na+, K+, and Cl-. This was retained with the intervention of UDCA. UDCA and VEK regulated the BA metabolism disorder to a certain extent. Analysis of gut microbiota showed that VEK increased the abundance of Lactobacillus and decreased that of Prevotella_9 in MAE rats. The combined administration of UDCA and VEK showed a better modulation of the microbiota structure than that of VEK alone, and the effect of this administration reached closer to the reference state. Conclusion: The water-expelling effect of VEK did not directly depend on the BA-mediated gut microbiota. However, VEK and BAs had a synergistic effect on malignant ascites effusion through the regulation of the gut microbiota. These results provided a scientific basis for the reasonable usage of VEK and the novel combination treatment strategy of VEK and UDCA.

The interaction of bile acids and gut inflammation influences the pathogenesis of inflammatory bowel disease

Bile acids (BA) are amphipathic molecules originating from cholesterol in the liver and from microbiota-driven biotransformation in the colon. In the gut, BA play a key role in fat digestion and absorption and act as potent signaling molecules on the nuclear farnesoid X receptor (FXR) and membrane-associated G protein-coupled BA receptor-1 (GPBAR-1). BA are, therefore, involved in the maintenance of gut barrier integrity, gene expression, metabolic homeostasis, and microbiota profile and function. Disturbed BA homeostasis can activate pro-inflammatory pathways in the gut, while inflammatory bowel diseases (IBD) can induce gut dysbiosis and qualitative and/or quantitative changes of the BA pool. These factors contribute to impaired repair capacity of the mucosal barrier, due to chronic inflammation. A better understanding of BA-dependent mechanisms paves the way to innovative therapeutic tools by administering hydrophilic BA and FXR agonists and manipulating gut microbiota with probiotics and prebiotics. We discuss the translational value of pathophysiological and therapeutic evidence linking BA homeostasis to gut inflammation in IBD.

Berberine improves DSS-induced colitis in mice by modulating the fecal-bacteria-related bile acid metabolism

Ulcerative colitis (UC) has been confirmed as a disease with a high incidence and low cure rate worldwide. In severe cases, UC can develop into colon cancer. Modern research has confirmed that berberine (BBR) can treat UC by inhibiting the expressions of inflammatory factors. However, the contribution of gut microbiota and flora metabolites in treating UC with BBR remains unclear. In this study, the ameliorative effects of BBR on gut microbiota dysbiosis and flora metabolites were investigated in a dextran sodium sulfate (DSS)-induced UC rodent model. We found that BBR significantly improved the pathological phenotype, attenuated intestinal barrier disruption, and mitigated colonic inflammation in DSS mice. By 16 S rDNA sequencing, BBR alleviated gut microbiota dysbiosis in UC mice. Moreover, the gut microbiota depletion experiment confirmed that the therapeutic effect of BBR was inextricably correlated with the gut microbiota. Besides, the flora metabolites (e.g., short-chain fatty acids, bile acids, and 5-hydroxytryptamine) were studied using HPLC-MS. The results suggested that BBR ameliorated the bile acid imbalance induced by DSS in the liver and gut. Furthermore, BBR treatment repaired gut barrier damage. The above results revealed that BBR alleviated DSS-induced UC in mice by restoring the disturbed gut microbiota, elevating unconjugated and secondary bile acids in the gastrointestinal tract, and activating the FXR and TGR5 signal pathway. This study provides novel insights into the mechanism of BBR in treating UC.

A unicentric cross-sectional observational study on chronic intestinal inflammation in total colonic aganglionosis: beware of an underestimated condition

BACKGROUND

Inflammatory Bowel Diseases (IBD) are known to occur in association with Hirschsprung disease (HSCR). Most of cases are represented by Crohn Disease (CD) occurring in patients with Total Colonic Aganglionosis (TCSA) with an estimated prevalence of around 2%. Based on these considerations and on a number of provisional data belonging to our Center for Digestive Diseases, we developed a unicentric cross-sectional observational study aimed at describing phenotype, genotype, pathology and metagenomics of all patients with TCSA and Crohn-like lesions.

RESULTS

Out of a series of 62 eligible TCSA patients, 48 fulfilled inclusion criteria and were enrolled in the study. Ten patients did not complete the study due to non-compliance or withdrawal of consent and were subsequently dropped out. A total of 38 patients completed the study. All patients were tested for chronic intestinal inflammation by a combination of fecal calprotectine (FC) or occult fecal blood (OFB) and underwent fecal metagenomics. Nineteen (50%) tested positive for FC, OFB, or both and subsequently underwent retrograde ileoscopy. Fourteen patients (36.8%) presented Crohn-like lesions, occurring after a median of 11.5 years after surgery (range 8 months - 21.5 years). No statistically significant differences regarding demographic, phenotype and genotype were observed comparing patients with and without lesions, except for need for blood transfusion that was more frequent in those with lesions. Faecal microbiome of patients with lesions (not that of caregivers) was less biodiverse and characterized by a reduction of Bacteroidetes, and an overabundance of Proteobacteria. FC tested negative in 3/14 patients with lesions (21%).

CONCLUSIONS

Our study demonstrated an impressive 10-folds higher incidence of chronic inflammation in TCSA. Up to 50% of patients may develop IBD-like lesions postoperatively. Nonetheless, we failed in identifying specific risk factors to be used to implement prevention strategies. Based on the results of our study, we suggest screening all TCSA patients with retrograde ileoscopy regardless of FC/OFB values. The frequency of endoscopic assessments and the role of FC/OFB screening in prompting endoscopy is yet to be determined.

Schisandrin protects against ulcerative colitis by inhibiting the SGK1/NLRP3 signaling pathway and reshaping gut microbiota in mice

BACKGROUND

According to the Chinese Pharmacopoeia, the fruit of Schisandra chinensis (Turcz.) Baill. (SC) is an important traditional Chinese medicine that can be used to treat diarrhea. Despite the increasing research on the anti-inflammatory and anti-oxidant aspects of SC, the studies on the anti-ulcerative colitis of Schisandrin (SCH), the main constituent of SC, are relatively few.

METHODS

The mice used in the study were randomly distributed into 6 groups: control, model, 5-ASA, and SCH (20, 40, 80 mg/kg/d). The mice in the model group were administered 3% (w/v) dextran sulfate sodium (DSS) through drinking water for 7 days, and the various parameters of disease activity index (DAI) such as body weight loss, stool consistency, and gross blood were measured. ELISA was used to detect inflammatory factors, and bioinformatics combined with transcriptome analysis was done to screen and verify relevant targets. 16S rDNA high-throughput sequencing was used to analyze the composition of the gut microbiota(GM), while mass spectrometry was done to analyze the changes in the content of bile acids (BAs) in the intestine.

RESULTS

Mice treated with SCH experienced significant weight gain, effectively alleviating the severity of colitis, and decreasing the levels of inflammatory factors such as TNF-α, IL-1β, IL-18, IL-6, and other related proteins (NLRP3, Caspase-1, SGK1) in UC mice. Furthermore, the analysis of GM and BAs in mice revealed that SCH increased the relative abundance of Lactobacilli spp, reduced the relative abundance of Bacteroides, and promoted the conversion of primary BAs to secondary BAs. These effects contributed to a significant improvement in the DSS-induced GM imbalance and the maintenance of intestinal homeostasis.

CONCLUSION

It seems that there is a close relationship between the SCH mechanism and the regulation of SGK1/NLRP3 pathway and the restoration of GM balance. Therefore, it can be concluded that SCH could be a potential drug for the treatment of UC.

Fecal Concentrations of Long-Chain Fatty Acids, Sterols, and Unconjugated Bile Acids in Cats with Chronic Enteropathy

Chronic enteropathy (CE) in cats encompasses food-responsive enteropathy, chronic inflammatory enteropathy (or inflammatory bowel disease), and low-grade intestinal T-cell lymphoma. While alterations in the gut metabolome have been extensively studied in humans and dogs with gastrointestinal disorders, little is known about the specific metabolic profile of cats with CE. As lipids take part in energy storage, inflammation, and cellular structure, investigating the lipid profile in cats with CE is crucial. This study aimed to measure fecal concentrations of various fatty acids, sterols, and bile acids. Fecal samples from 56 cats with CE and 77 healthy control cats were analyzed using gas chromatography-mass spectrometry, targeting 12 fatty acids, 10 sterols, and 5 unconjugated bile acids. Fecal concentrations of nine targeted fatty acids and animal-derived sterols were significantly increased in cats with CE. However, fecal concentrations of plant-derived sterols were significantly decreased in cats with CE. Additionally, an increased percentage of primary bile acids was observed in a subset of cats with CE. These findings suggest the presence of lipid maldigestion, malabsorption, and inflammation in the gastrointestinal tract of cats with CE. Understanding the lipid alterations in cats with CE can provide insights into the disease mechanisms and potential future therapeutic strategies.

A gut-restricted glutamate carboxypeptidase II inhibitor reduces monocytic inflammation and improves preclinical colitis

There is an urgent need to develop therapeutics for inflammatory bowel disease (IBD) because up to 40% of patients with moderate-to-severe IBD are not adequately controlled with existing drugs. Glutamate carboxypeptidase II (GCPII) has emerged as a promising therapeutic target. This enzyme is minimally expressed in normal ileum and colon, but it is markedly up-regulated in biopsies from patients with IBD and preclinical colitis models. Here, we generated a class of GCPII inhibitors designed to be gut-restricted for oral administration, and we interrogated efficacy and mechanism using in vitro and in vivo models. The lead inhibitor, (S)-IBD3540, was potent (half maximal inhibitory concentration = 4 nanomolar), selective, gut-restricted (AUCcolon/plasma > 50 in mice with colitis), and efficacious in acute and chronic rodent colitis models. In dextran sulfate sodium-induced colitis, oral (S)-IBD3540 inhibited >75% of colon GCPII activity, dose-dependently improved gross and histologic disease, and markedly attenuated monocytic inflammation. In spontaneous colitis in interleukin-10 (IL-10) knockout mice, once-daily oral (S)-IBD3540 initiated after disease onset improved disease, normalized colon histology, and attenuated inflammation as evidenced by reduced fecal lipocalin 2 and colon pro-inflammatory cytokines/chemokines, including tumor necrosis factor-α and IL-17. Using primary human colon epithelial air-liquid interface monolayers to interrogate the mechanism, we further found that (S)-IBD3540 protected against submersion-induced oxidative stress injury by decreasing barrier permeability, normalizing tight junction protein expression, and reducing procaspase-3 activation. Together, this work demonstrated that local inhibition of dysregulated gastrointestinal GCPII using the gut-restricted, orally active, small-molecule (S)-IBD3540 is a promising approach for IBD treatment.

Bile acid-activated receptors in innate and adaptive immunity: targeted drugs and biological agents

Bile acid-activated receptors (BARs) such as a G-protein bile acid receptor 1 and the farnesol X receptor are activated by bile acids (BAs) and have been implicated in the regulation of microbiota-host immunity in the intestine. The mechanistic roles of these receptors in immune signaling suggest that they may also influence the development of metabolic disorders. In this perspective, we provide a summary of recent literature describing the main regulatory pathways and mechanisms of BARs and how they affect both innate and adaptive immune system, cell proliferation, and signaling in the context of inflammatory diseases. We also discuss new approaches for therapy and summarize clinical projects on BAs for the treatment of diseases. In parallel, some drugs that are classically used for other therapeutic purposes and BAR activity have recently been proposed as regulators of immune cells phenotype. Another strategy consists of using specific strains of gut bacteria to regulate BA production in the intestine.

The Potential of Bile Acids as Biomarkers for Metabolic Disorders

Bile acids (BAs) are well known to facilitate the absorption of dietary fat and fat-soluble molecules. These unique steroids also function by binding to the ubiquitous cell membranes and nuclear receptors. As chemical signals in gut-liver axis, the presence of metabolic disorders such as nonalcoholic fatty liver disease (NAFLD), type 2 diabetes mellitus (T2DM), and even tumors have been reported to be closely related to abnormal levels of BAs in the blood and fecal metabolites of patients. Thus, the gut microbiota interacting with BAs and altering BA metabolism are critical in the pathogenesis of numerous chronic diseases. This review intends to summarize the mechanistic links between metabolic disorders and BAs in gut-liver axis, and such stage-specific BA perturbation patterns may provide clues for developing new auxiliary diagnostic means.

Insulin alleviates murine colitis through microbiome alterations and bile acid metabolism

BACKGROUND

Insulin has been reported to exhibit anti-inflammatory activities in the context of bowel inflammation. However, the role of the interaction between insulin and the microbiota in gut health is unclear. Our goal was to investigate the mechanism of action of insulin in bowel inflammation and the relationship between insulin and the gut microbiota.

METHODS

We used acute and chronic murine models of inflammatory bowel disease (IBD) to evaluate whether insulin influences the progression of colitis. Colonic tissues, the host metabolome and the gut microbiome were analyzed to investigate the relationship among insulin treatment, the microbiome, and disease. Experiments involving antibiotic (Abx) treatment and fecal microbiota transplantation (FMT) confirmed the association among the gut microbiota, insulin and IBD. In a series of experiments, we further defined the mechanisms underlying the anti-inflammatory effects of insulin.

RESULTS

We found that low-dose insulin treatment alleviated intestinal inflammation but did not cause death. These effects were dependent on the gut microbiota, as confirmed by experiments involving Abx treatment and FMT. Using untargeted metabolomic profiling and 16S rRNA sequencing, we discovered that the level of the secondary bile acid lithocholic acid (LCA) was notably increased and the LCA levels were significantly associated with the abundance of Blautia, Enterorhadus and Rumi-NK4A214_group. Furthermore, LCA exerted anti-inflammatory effects by activating a G-protein-coupled bile acid receptor (TGR5), which inhibited the polarization of classically activated (M1) macrophages.

CONCLUSION

Together, these data suggest that insulin alters the gut microbiota and affects LCA production, ultimately delaying the progression of IBD.

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.

Optimization and Impurity Control Strategy for Lithocholic Acid Production Using Commercially Plant-Sourced Bisnoralcohol

In this study, lithocholic acid (LCA) was prepared using commercially available plant-sourced bisnoralcohol (BA), and the overall yield of the product was 70.6% for five steps. To prevent process-related impurities, the isomerizations of catalytic hydrogenation in the C4-C5 double bond and reduction of the 3-keto group were optimized. The double bond reduction isomerization was improved (5β-H:5α-H = 97:3) using palladium-copper nanowires (Pd-Cu NWs) instead of Pd/C. The reduction of the 3-keto group was 100% converted to a 3α-OH product by 3α-hydroxysteroid dehydrogenase/carbonyl reductase catalysis. Moreover, the impurities during the optimization process were comprehensively studied. Compared with the reported synthesis methods, our developed method significantly improved the isomer ratio and overall yield, affording ICH-grade quality of LCA, and it is more cost-effective and suitable for large-scale production of LCA.

Oligosaccharides as Potential Regulators of Gut Microbiota and Intestinal Health in Post-COVID-19 Management

The COVID-19 pandemic has had a profound impact worldwide, resulting in long-term health effects for many individuals. Recently, as more and more people recover from COVID-19, there is an increasing need to identify effective management strategies for post-COVID-19 syndrome, which may include diarrhea, fatigue, and chronic inflammation. Oligosaccharides derived from natural resources have been shown to have prebiotic effects, and emerging evidence suggests that they may also have immunomodulatory and anti-inflammatory effects, which could be particularly relevant in mitigating the long-term effects of COVID-19. In this review, we explore the potential of oligosaccharides as regulators of gut microbiota and intestinal health in post-COVID-19 management. We discuss the complex interactions between the gut microbiota, their functional metabolites, such as short-chain fatty acids, and the immune system, highlighting the potential of oligosaccharides to improve gut health and manage post-COVID-19 syndrome. Furthermore, we review evidence of gut microbiota with angiotensin-converting enzyme 2 expression for alleviating post-COVID-19 syndrome. Therefore, oligosaccharides offer a safe, natural, and effective approach to potentially improving gut microbiota, intestinal health, and overall health outcomes in post-COVID-19 management.

Altered fecal microbiome and metabolome profiles in rat models of short bowel syndrome

Introduction

Short bowel syndrome (SBS) is featured by impaired nutrients and fluids absorption due to massive small intestine resection. Gut dysbiosis has been implicated in SBS, this study aimed to characterize the metagenomic and metabolomic profiles of SBS and identify potential therapeutic targets.

Methods

Fecal samples from SBS and Sham rats (n = 8 per group) were collected for high-throughput metagenomic sequencing. Fecal metabolomics was measured by untargeted liquid chromatography-mass spectrometry.

Results

We found that the species-level α-diversity significantly decreased in SBS rats, accompanied by altered microbiome compositions. The beneficial anaerobes from Firmicutes and Bacteroidetes were depleted while microorganisms from Lactobacillus, Escherichia, Enterococcus, and Streptococcus were enriched in faces from SBS rats. LEfSe analysis identified 17 microbial species and 38 KEGG modules that were remarkably distinct between SBS and Sham rats. In total, 1,577 metabolites with known chemical identity were detected from all samples, among them, 276 metabolites were down-regulated and 224 metabolites were up-regulated in SBS group. The typical signatures of SBS fecal metabolome comprised reduced short-chain fatty acids and products of amino acid metabolism (indole derivatives and p-cresol), as well as altered bile acid spectrum. We revealed 215 robust associations between representative differentially abundant microbial species and metabolites, the species with the same changing trend tended to have a similar correlation with some certain metabolites.

Conclusion

The fecal microbiome and metabolome significantly altered in SBS. Our findings may lay the foundation for developing new strategies to facilitate intestinal adaptation in SBS patients.

A microbiota-modulated checkpoint directs immunosuppressive intestinal T cells into cancers

Antibiotics (ABX) compromise the efficacy of programmed cell death protein 1 (PD-1) blockade in cancer patients, but the mechanisms underlying their immunosuppressive effects remain unknown. By inducing the down-regulation of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in the ileum, post-ABX gut recolonization by Enterocloster species drove the emigration of enterotropic α4β7+CD4+ regulatory T 17 cells into the tumor. These deleterious ABX effects were mimicked by oral gavage of Enterocloster species, by genetic deficiency, or by antibody-mediated neutralization of MAdCAM-1 and its receptor, α4β7 integrin. By contrast, fecal microbiota transplantation or interleukin-17A neutralization prevented ABX-induced immunosuppression. In independent lung, kidney, and bladder cancer patient cohorts, low serum levels of soluble MAdCAM-1 had a negative prognostic impact. Thus, the MAdCAM-1-α4β7 axis constitutes an actionable gut immune checkpoint in cancer immunosurveillance.

Crohn’s disease: Why the ileum?

Crohn’s disease (CD) is an inflammatory bowel disease characterized by immune-mediated flares affecting any region of the intestine alternating with remission periods. In CD, the ileum is frequently affected and about one third of patients presents with a pure ileal type. Moreover, the ileal type of CD presents epidemiological specificities like a younger age at onset and often a strong link with smoking and genetic susceptibility genes. Most of these genes are associated with Paneth cell dysfunction, a cell type found in the intestinal crypts of the ileum. Besides, a Western-type diet is associated in epidemiological studies with CD onset and increasing evidence shows that diet can modulate the composition of bile acids and gut microbiota, which in turn modulates the susceptibility of the ileum to inflammation. Thus, the interplay between environmental factors and the histological and anatomical features of the ileum is thought to explain the specific transcriptome profile observed in CD ileitis. Indeed, both immune response and cellular healing processes harbour differences between ileal and non-ileal CD. Taken together, these findings advocate for a dedicated therapeutic approach to managing ileal CD. Currently, interventional pharmacological studies have failed to clearly demonstrate distinct response profiles according to disease site. However, the high rate of stricturing disease in ileal CD requires the identification of new therapeutic targets to significantly change the natural history of this debilitating disease.

Gut microbiota derived bile acid metabolites maintain the homeostasis of gut and systemic immunity

Bile acids (BAs) as cholesterol-derived molecules play an essential role in some physiological processes such as nutrient absorption, glucose homeostasis and regulation of energy expenditure. They are synthesized in the liver as primary BAs such as cholic acid (CA), chenodeoxycholic acid (CDCA) and conjugated forms. A variety of secondary BAs such as deoxycholic acid (DCA) and lithocholic acid (LCA) and their derivatives is synthesized in the intestine through the involvement of various microorganisms. In addition to essential physiological functions, BAs and their metabolites are also involved in the differentiation and functions of innate and adaptive immune cells such as macrophages (Macs), dendritic cells (DCs), myeloid derived suppressive cells (MDSCs), regulatory T cells (Treg), Breg cells, T helper (Th)17 cells, CD4 Th1 and Th2 cells, CD8 cells, B cells and NKT cells. Dysregulation of the BAs and their metabolites also affects development of some diseases such as inflammatory bowel diseases. We here summarize recent advances in how BAs and their metabolites maintain gut and systemic homeostasis, including the metabolism of the BAs and their derivatives, the role of BAs and their metabolites in the differentiation and function of immune cells, and the effects of BAs and their metabolites on immune-associated disorders.

Pharmaceutical characterization of probucol bile acid-lithocholic acid nanoparticles to prevent chronic hearing related and similar cellular oxidative stress pathologies

Background: Sensorineural hearing loss has been associated with oxidative stress. However, an antioxidant that passes effectively through the ear remains elusive. Method: Probucol (PB)-based nanoparticles were formed using a spray-drying encapsulation technique, characterized and tested in vitro. Results: Uniform, spherical nanoparticles were produced. The addition of lithocholic acid to PB formulations did not affect drug content or production yield, but it did modify capsule size, surface tension, electrokinetic stability and drug release. Cell viability, bioenergetics and inflammatory profiles were improved when auditory cells were exposed to PB-based nanoparticles, which showed antioxidant properties (p < 0.05). Conclusion: PB-based nanoparticles can potentially protect the auditory cell line from oxidative stress and could be used in future in vivo studies as a potential new therapeutic agent for sensorineural hearing loss.

The Role of Microbiota-Derived Metabolites in Colorectal Cancer

The impact of bacterial members of the microbiota on the development of colorectal cancer (CRC) has become clear in recent years. However, exactly how bacteria contribute to the development of cancer is often still up for debate. The impact of bacteria-derived metabolites, which can influence the development of CRC either in a promoting or inhibiting manner, is undeniable. Here, we discuss the effects of the most well-studied bacteria-derived metabolites associated with CRC, including secondary bile acids, short-chain fatty acids, trimethylamine-N-oxide and indoles. We show that the effects of individual metabolites on CRC development are often nuanced and dose- and location-dependent. In the coming years, the array of metabolites involved in CRC development will undoubtedly increase further, which will emphasize the need to focus on causation and mechanisms and the clearly defined roles of bacterial species within the microbiota.

Amelioration of Colitis by a Gut Bacterial Consortium Producing Anti-Inflammatory Secondary Bile Acids

The Integrative Human Microbiome Project and other cohort studies have indicated that inflammatory bowel disease is accompanied by dysbiosis of gut microbiota, decreased production of secondary bile acids, and increased levels of primary bile acids. Secondary bile acids, such as ursodeoxycholic acid (UDCA) and lithocholic acid (LCA), have been reported to be anti-inflammatory, yet it remains to be studied whether introducing selected bacteria strains to restore bile acid metabolism of the gut microbiome can alleviate intestinal inflammation. In this study, we screened human gut bacterial strains for bile acid metabolism and designed a consortium of three species, including Clostridium AP sp000509125, Bacteroides ovatus, and Eubacterium limosum, and named it BAC (bile acid consortium). We showed that the three-strain gut bacterial consortium BAC is capable of converting conjugated primary bile acids taurochenodeoxycholic acid and glycochenodeoxycholic acid to secondary bile acids UDCA and LCA in vitro. Oral gavage treatment with BAC in mice resulted in protective effects against dextran sulfate sodium (DSS)-induced colitis, including reduced weight loss and increased colon length. Furthermore, BAC treatment increased the fecal level of bile acids, including UDCA and LCA. BAC treatment enhanced intestinal barrier function, which may be attributed to the increased activation of the bile acid receptor TGR5 by secondary bile acids. Finally, we examined the remodeling of gut microbiota by BAC treatment. Taken together, the three-strain gut bacterial consortium BAC restored the dysregulated bile acid metabolism and alleviated DSS-induced colitis. Our study provides a proof-of-concept demonstration that a rationally designed bacterial consortium can reshape the metabolism of the gut microbiome to treat diseases. IMPORTANCE Secondary bile acids have been reported to be anti-inflammatory, yet it remains to be studied whether introducing selected bacteria strains to restore bile acid metabolism of the gut microbiome can alleviate intestinal inflammation. To address this gap, we designed a consortium of human gut bacterial strains based on their metabolic capacity to produce secondary bile acids UDCA and LCA, and we evaluated the efficacy of single bacterial strains and the bacterial consortium in treating the murine colitis model. We found that oral gavage of the bacterial consortium to mice restored secondary bile acid metabolism to increase levels of UDCA and LCA, which induced the activation of TGR5 to improve gut-barrier integrity and reduced the inflammation in murine colitis. Overall, our study demonstrates that rationally designed bacterial consortia can reshape the metabolism of the gut microbiome and provides novel insights into the application of live biotherapeutics for treating IBD.

Vitamin D Receptor Mediates Attenuating Effect of Lithocholic Acid on Dextran Sulfate Sodium Induced Colitis in Mice

Bile acids are major components of bile; they emulsify dietary lipids for efficient digestion and absorption and act as signaling molecules that activate nuclear and membrane receptors. The vitamin D receptor (VDR) is a receptor for the active form of vitamin D and lithocholic acid (LCA), a secondary bile acid produced by the intestinal microflora. Unlike other bile acids that enter the enterohepatic circulation, LCA is poorly absorbed in the intestine. Although vitamin D signaling regulates various physiological functions, including calcium metabolism and inflammation/immunity, LCA signaling remains largely unknown. In this study, we investigated the effect of the oral administration of LCA on colitis in a mouse model using dextran sulfate sodium (DSS). Oral LCA decreased the disease activity of colitis in the early phase, which is a phenotype associated with the suppression of histological injury, such as inflammatory cell infiltration and goblet cell loss. These protective effects of LCA were abolished in VDR-deleted mice. LCA decreased the expression of inflammatory cytokine genes, but this effect was at least partly observed in VDR-deleted mice. The pharmacological effect of LCA on colitis was not associated with hypercalcemia, an adverse effect induced by vitamin D compounds. Therefore, LCA suppresses DSS-induced intestinal injury in its action as a VDR ligand.

Effects of hemicellulose on intestinal mucosal barrier integrity, gut microbiota, and metabolomics in a mouse model of type 2 diabetes mellitus

Background and objective

Impaired gut barrier contributes to the progression of type 2 diabetes mellitus (T2DM), and the gut microbiota and metabolome play an important role in it. Hemicellulose, a potential prebiotics, how its supplementation impacted the glucose level, the impaired gut barrier, and the gut microbiota and metabolome in T2DM remained unclear.

Methods

In this study, some mice were arranged randomly into four groups: db/db mice fed by a compositionally defined diet (CDD), db/db mice fed by a CDD with 10% and 20% hemicellulose supplementation, and control mice fed by a CDD. Body weight and fasting blood glucose levels were monitored weekly. The gut barrier was evaluated. Fresh stool samples were analyzed using metagenomic sequencing and liquid chromatography-mass spectrometry to detect gut microbiota and metabolome changes. Systemic and colonic inflammation were evaluated.

Results

Better glycemic control, restoration of the impaired gut barrier, and lowered systemic inflammation levels were observed in db/db mice with the supplementation of 10 or 20% hemicellulose. The gut microbiota showed significant differences in beta diversity among the four groups. Fifteen genera with differential relative abundances and 59 significantly different metabolites were found. In the db/db group, hemicellulose eliminated the redundant Faecalibaculum and Enterorhabdus. The increased succinate and ursodeoxycholic acid (UDCA) after hemicellulose treatment were negatively correlated with Bifidobacterium, Erysipelatoclostridium, and Faecalibaculum. In addition, hemicellulose reduced the colonic expressions of TLR2/4 and TNF-α in db/db mice.

Conclusion

Hemicellulose may serve as a potential therapeutic intervention for T2DM by improving impaired intestinal mucosal barrier integrity, modulating gut microbiota composition, and altering the metabolic profile.

Irradiation-Induced Intestinal Injury is Associated With Disorders of Bile Acids Metabolism

PURPOSE

Intestinal injury commonly occurs in radiation therapy, but its pathogenesis is not well understood. The relationship between irradiation-induced intestinal injury and bile acids (BAs) metabolism remains elusive. This study intends to clarify the role of BAs metabolism in irradiation-induced intestinal injury and the potential for supplementation with BAs to alleviate this injury.

MATERIALS AND METHODS

BAs metabolomic analysis of fecal pellets from normal and 12 Gy γ-ray total abdominal irradiation (TAI) treated mice was performed. The effects of a crude bile extract (BAmix) or lithocholic acid (LCA) on mice exposed to 12 Gy γ-ray TAI were determined by analyzing weight loss, colon length, villus length, crypt number, and the expression of leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) and yes-associated protein 1 (YAP1). The effects of BAmix or LCA on intestinal organoids after 4 Gy irradiation were analyzed. ELISA assay was applied to test IL-1β, IL-6 and TNF-α levels in mouse intestine. The expression changes of G protein-coupled receptor 1 (TGR5) and YAP1 in the colonic mucosa of patients with radiation-induced intestinal injury were determined by IHC.

RESULTS

The relative abundance of secondary BAs was decreased while the relative abundance of primary BAs was increased in irradiated mice, and LCA was the most obvious change. BAmix and LCA alleviated irradiation-induced intestinal injury in a mouse model, as reflected by reduced body weight loss, longer colon, higher villus, more crypts, and increased Lgr5 expression. In intestinal organoids, BAmix and LCA enhanced newborn crypts formation after irradiation. LCA treatment improved the expression of TGR5 and YAP1 in mouse intestinal crypts. LCA has potential to reduce the inflammation levels in irradiated mice. Additionally, the expression levels of TGR5 and YAP1 in the colonic mucosa of patients with radiation enteritis were also significantly decreased.

CONCLUSIONS

Radiation-induced intestinal injury is associated with disorders of BAs metabolism, and treatment with LCA had a protective effect against radiation-induced intestinal injury in mice by modulating TGR5 and YAP1.

Therapeutic role of ursodeoxycholic acid in colitis-associated cancer via gut microbiota modulation

Inflammatory bowel disease (IBD) is a predisposing factor for colitis-associated cancer (CAC). The association between bile acids and the gut microbiota has been demonstrated in colon neoplasia; however, the effect of ursodeoxycholic acid (UDCA) on gut microbiota alteration in development of colitis and CAC is unknown. Our analysis of publicly available datasets demonstrated the association of UDCA treatment and accumulation of Akkermansia. UDCA-mediated alleviation of DSS-induced colitis was microbially dependent. UDCA treatment significantly upregulated Akkermansia colonization in a mouse model. Colonization of Akkermansia was associated with enhancement of the mucus layer upon UDCA treatment as well as activation of bile acid receptors in macrophages. UDCA played a role in CAC prevention and treatment in the AOM-DSS and ApcMin/+-DSS models through downregulation of inflammation and accumulation of Akkermansia. This study suggests that UDCA intervention could reshape intestinal gut homeostasis, facilitating colonization of Akkermansia and preventing and treating colitis and CAC.

Sex, puberty, and the gut microbiome

In brief

Sex differences in the gut microbiome may impact multiple aspects of human health and disease. In this study, we review the evidence for microbial sex differences in puberty and adulthood and discuss potential mechanisms driving differentiation of the sex-specific gut microbiome.

Abstract

In humans, the gut microbiome is strongly implicated in numerous sex-specific physiological processes and diseases. Given this, it is important to understand how sex differentiation of the gut microbiome occurs and how these differences contribute to host health and disease. While it is commonly believed that the gut microbiome stabilizes after 3 years of age, our review of the literature found considerable evidence that the gut microbiome continues to mature during and after puberty in a sex-dependent manner. We also review the intriguing, though sparse, literature on potential mechanisms by which host sex may influence the gut microbiome, and vice versa, via sex steroids, bile acids, and the immune system. We conclude that the evidence for the existence of a sex-specific gut microbiome is strong but that there is a dearth of research on how host-microbe interactions lead to this differentiation. Finally, we discuss the types of future studies needed to understand the processes driving the maturation of sex-specific microbial communities and the interplay between gut microbiota, host sex, and human health.

GPBAR1 is associated with asynchronous bone metastasis and poor prognosis of hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death in China. Asynchronous metastasis is the main reason for HCC recurrence, but the current assessment of HCC metastasis and prognosis is far from clinically satisfactory.

Materials

In our study, we investigated the expression of G-protein-coupled bile acid receptor (GPBAR1) in HCC tissues and tumor-adjacent tissues by qRT-PCR and immunohistochemistry. The associations between GPBAR1 expression, clinicopathological factors, and asynchronous metastases were assessed by the Chi-square test. The overall survival curves of different variables were plotted with the Kaplan-Meier method, and the statistical significance between different subgroups was analyzed with the log-rank test. The independent prognostic factors were identified by the Cox regression hazard model.

Results

GPBAR1 was more highly expressed in HCC tissues than in tumor-adjacent tissues. GPBAR1 expression in HCC was significantly higher than that in liver cirrhosis, followed by normal liver tissues. GPBAR1 was significantly associated with poor prognosis in HCC and can be regarded as an independent prognostic biomarker. Interestingly, GPBAR1 expression in HCC was significantly correlated with asynchronous metastasis to the bone but not to the liver or lung.

Conclusions

GPBAR1 was found to be an independent, unfavorable prognostic factor of HCC, as well as an indicator of asynchronous bone metastasis but not liver or lung metastases. Our results could provide a new aspect for HCC metastasis studies and help identify high-risk HCC patients, which helps ameliorate the prognostic assessment of HCC.

Dietary-Induced Bacterial Metabolites Reduce Inflammation and Inflammation-Associated Cancer via Vitamin D Pathway

Environmental factors, including westernised diets and alterations to the gut microbiota, are considered risk factors for inflammatory bowel diseases (IBD). The mechanisms underpinning diet-microbiota-host interactions are poorly understood in IBD. We present evidence that feeding a lard-based high-fat (HF) diet can protect mice from developing DSS-induced acute and chronic colitis and colitis-associated cancer (CAC) by significantly reducing tumour burden/incidence, immune cell infiltration, cytokine profile, and cell proliferation. We show that HF protection was associated with increased gut microbial diversity and a significant reduction in Proteobacteria and an increase in Firmicutes and Clostridium cluster XIVa abundance. Microbial functionality was modulated in terms of signalling fatty acids and bile acids (BA). Faecal secondary BAs were significantly induced to include moieties that can activate the vitamin D receptor (VDR), a nuclear receptor richly represented in the intestine and colon. Indeed, colonic VDR downstream target genes were upregulated in HF-fed mice and in combinatorial lipid-BAs-treated intestinal HT29 epithelial cells. Collectively, our data indicate that HF diet protects against colitis and CAC risk through gut microbiota and BA metabolites modulating vitamin D targeting pathways. Our data highlights the complex relationship between dietary fat-induced alterations of microbiota-host interactions in IBD/CAC pathophysiology.

Microbiota of the gastrointestinal tract: Friend or foe?

The gut microbiota is currently considered an external organ of the human body that provides important mechanisms of metabolic regulation and protection. The gut microbiota encodes over 3 million genes, which is approximately 150 times more than the total number of genes present in the human genome. Changes in the qualitative and quantitative composition of the microbiome lead to disruption in the synthesis of key bacterial metabolites, changes in intestinal barrier function, and inflammation and can cause the development of a wide variety of diseases, such as diabetes, obesity, gastrointestinal disorders, cardiovascular issues, neurological disorders and oncological concerns. In this review, I consider issues related to the role of the microbiome in the regulation of intestinal barrier function, its influence on physiological and pathological processes occurring in the body, and potential new therapeutic strategies aimed at restoring the gut microbiome. Herewith, it is important to understand that the gut microbiota and human body should be considered as a single biological system, where change of one element will inevitably affect its other components. Thus, the study of the impact of the intestinal microbiota on health should be considered only taking into account numerous factors, the role of which has not yet been fully elucidated.

Alterations in Peripheral Metabolites as Key Actors in Alzheimer's Disease

Growing evidence supports that Alzheimer's disease (AD) could be regarded as a metabolic disease, accompanying central and peripheral metabolic disturbance. Nowadays, exploring novel and potentially alternative hallmarks for AD is needed. Peripheral metabolites based on blood and gut may provide new biochemical insights about disease mechanisms. These metabolites can influence brain energy homeostasis, maintain gut mucosal integrity, and regulate the host immune system, which may further play a key role in modulating the cognitive function and behavior of AD. Recently, metabolomics has been used to identify key AD-related metabolic changes and define metabolic changes during AD disease trajectory. This review aims to summarize the key blood- and microbial-derived metabolites that are altered in AD and identify the potential metabolic biomarkers of AD, which will provide future targets for precision therapeutic modulation.

Bile acids as inflammatory mediators and modulators of intestinal permeability

Bile acids are critical for the digestion and absorption of lipids and fat-soluble vitamins; however, evidence continues to emerge supporting additional roles for bile acids as signaling molecules. After they are synthesized from cholesterol in the liver, primary bile acids are modified into secondary bile acids by gut flora contributing to a diverse pool and making the composition of bile acids highly sensitive to alterations in gut microbiota. Disturbances in bile acid homeostasis have been observed in patients with Inflammatory Bowel Diseases (IBD). In fact, a decrease in secondary bile acids was shown to occur because of IBD-associated dysbiosis. Further, the increase in luminal bile acids due to malabsorption in Crohn's ileitis and ileal resection has been implicated in the induction of diarrhea and the exacerbation of inflammation. A causal link between bile acid signaling and intestinal inflammation has been recently suggested. With respect to potential mechanisms related to bile acids and IBD, several studies have provided strong evidence for direct effects of bile acids on intestinal permeability in porcine and rodent models as well as in humans. Interestingly, different bile acids were shown to exert distinct effects on the inflammatory response and intestinal permeability that require careful consideration. Such findings revealed a potential effect for changes in the relative abundance of different bile acids on the induction of inflammation by bile acids and the development of IBD. This review summarizes current knowledge about the roles for bile acids as inflammatory mediators and modulators of intestinal permeability mainly in the context of inflammatory bowel diseases.