Intestinal Bile Research Articles

Prevalence of Clostridioides difficile in Canine Feces and Its Association with Intestinal Dysbiosis.

The role of Clostridioides (C.) difficile as an enteropathogen in dogs is controversial. In humans, intestinal bile acid-dysmetabolism is associated with C. difficile prevalence. The relationship between fecal qPCR-based dysbiosis index (DI) and especially the abundance of bile acid-converting Clostridium hiranonis with the presence of C. difficile in dogs was explored across the following 4 cohorts: 358 fecal samples submitted for routine diagnostic work-up, 33 dogs with chronic enteropathy, 14 dogs with acute diarrhea, and 116 healthy dogs. Dogs that tested positive for C. difficile had significantly higher DI (median, 4.4 (range from 0.4 to 8.6)) and lower C. hiranonis (median, 0.1 (range from 0.0 to 7.5) logDNA/g) than dogs that tested negative for C. difficile (median DI, -1 (range from -7.2 to 8.9); median C. hiranonis abundance, 6.2 (range from 0.1 to 7.5) logDNA/g; p < 0.0001, respectively). In 33 dogs with CE and 14 dogs with acute diarrhea, the treatment response did not differ between C. difficile-positive and -negative dogs. In the group of clinically healthy dogs, 9/116 tested positive for C. difficile, and 6/9 of these had also an abnormal DI. In conclusion, C. difficile is strongly linked to intestinal dysbiosis and lower C. hiranonis levels in dogs, but its presence does not necessitate targeted treatment.

Effect of chin brick tea [Camellia sinensis (L.) Kuntze] on lipid metabolism and inflammation by modulating intestinal flora and bile acids in mice with non-alcoholic fatty liver disease

Ethnopharmacological relevanceTea (Camellia sinensis) has been consumed for centuries as a traditional remedy for various metabolic diseases. The pharmacological mechanisms of many conventional medicines, including tea, often need to be clarified. Chin brick tea is a unique Chinese black tea grown in Hubei, China, rich in tea elements such as tea polyphenols and tea polysaccharides. Aim of the studyWe focus on the effects of commercial chin brick tea on non-alcoholic fatty liver disease by altering intestinal flora and its metabolite, bile acids. Materials and methodsTargeted UPLC-MS/MS was employed to quantify the tea elements in commercial chin brick tea. In this study, we performed an integrated approach of animal experiments, 16 S rDNA, and ultra-performance liquid chromatography-tandem mass spectrometry to explore the potential mechanism of action of chin brick tea in preventing non-alcoholic fatty liver disease (NAFLD). ResultsAfter 14 weeks of administration, CBT extract could signiffcantly decrease the levels of body weight, liver weight, LDL-C, TC, ALT, IL-1β and IL-18, and slight increase HDL-C levels in NAFLD mice. The results indicated that the interventional impact of CBT with high-fat diet-induced NAFLD might depend on intestinal flora and its metabolites bile acids. Moreover, sequencing of 16 S rRNA genes demonstrated that CBT could signiffcantly improve the intestinal flora disorder of NAFLD mice. Speciffcally, CBT increased the levels of Lactobacillus, Alloprevotella, and Ruminococcaceae, while reducing the levels of Bacteroides in NAFLD mice. Then, a total of 23 bile acids were identified, 17 differential bile acids were obtained by screening, and CBT increase the primary bile acids/secondary bile acids ratio in NAFLD mice. Additionally, correlation analysis revealed that Bacteroides was negatively correlated with DCA and ωMCA, Lactobacillus was positively correlated with DCA and ωMCA, Bacteroides was positively correlated with NAFLD, Lactobacillus was negatively associated with NAFLD, and DCA and ωMCA were negatively correlated with NAFLD. ConclusionCBT extract has a good interventional impact on NAFLD mice. The mechanism by which this extract exerts its action is, at least partly, related to its regulation of intestinal flora and its metabolites bile acids.

Inulin ameliorates metabolic syndrome in high-fat diet-fed mice by regulating gut microbiota and bile acid excretion.

Background: Inulin is a natural plant extract that improves metabolic syndrome by modulating the gut microbiota. Changes in the gut microbiota may affect intestinal bile acids. We suggest that inulin may improve metabolism by inducing bile acid excretion by gut microbes. Methods: Male C57/BL mice were fed either a high-fat diet (60% calories) or a regular diet for 16weeks, with oral inulin (10% w/w). At the end of the experiment, the gene expression levels (FGF15, CD36, Srebp-1c, FASN, and ACC) in the liver and intestines, as well as the serum levels of triglycerides (TGs), low-density lipoprotein (LDL) cholesterol, total cholesterol, and free fatty acids, were collected. The expression of FGF15 was examined using Western blot analysis. The fat distribution in the liver and groin was detected by oil red and hematoxylin and eosin staining. Simultaneously, the levels of serum inflammatory factors (alanine aminotransferase and aspartate aminotransferase) were detected to explore the side effects of inulin. Results: Inulin significantly improved glucose tolerance and insulin sensitivity, and decreased body weight and serum TG and LDL levels, in mice fed normal diet. Furthermore, inulin increased the α-diversity of the gut microbiota and increased the fecal bile acid and TG excretion in inulin-treated mice. In addition, inulin significantly reduced lipid accumulation in liver and inguinal fat, white fat weight, and hepatic steatosis. Western blot analysis showed that inulin reduced the expression of FGF15, a bile acid reabsorption protein. Conclusion: Inulin ameliorates the glucose and lipid metabolic phenotypes of mice fed a normal diet, including decreased intestinal lipid absorption, increased glucose tolerance, increased insulin sensitivity, and decreased body weight. These changes may be caused by an increase in bile acid excretion resulting from changes in the gut microbiota that affect intestinal lipid absorption.

Red ginseng extracts ameliorate high-fat diet-induced obesity and insulin resistance by activating the intestinal TGR5-mediated bile acids signaling pathway

BackgroundObesity has emerged as a worldwide metabolic disease, given its rapid growth in global prevalence. Red ginseng extracts (RGS), one of the traditional processed products of ginseng, show the potential to improve the metabolic phenotype of obesity. However, the RGS mechanism for regulating obesity and late insulin resistance remains to be clarified. PurposeThis study aimed to emphasize the potential use of RGS in treatment of obesity and insulin resistance (IR) and explore the underlying mechanism affecting glucose and lipid metabolism improvements. MethodsThe role of RGS was evaluated in a high-fat diet (HFD) rodent model. Glucose tolerance test (GTT) and insulin tolerance test (ITT) were performed to characterize the glucose metabolism level. The expression of lipolysis proteins and uncoupling protein-1 (UCP-1) were investigated by western blot. Glucagon-like peptide-1 (GLP-1) and apical sodium-dependent bile acid transporter (ASBT) protein expression in the intestine were determined via immunofluorescence. UPLC-Q-TOF-MS were used to detect the alterations in bile acids (BAs) levels in serum, ileum, and inguinal white adipose tissue (iWAT). In addition, intestine-specific Tgr5 knockout mice were employed to verify the efficacy of RGS in improving obesity. ResultsRGS treatment alleviated dietary-induced dyslipidemia and IR in obese mice in a dose-dependent manner and improved glucose and insulin tolerance, and energy expenditure. RGS treatment significantly reduced lipid deposition and induced GLP-1 secretion in the intestine of wild-type mice but not in Tgr5ΔIN obese mice. Furthermore, RGS intervention increased BA levels in serum, ileum, and iWAT. The increase of circulating BAs in mice was related to the activation of ileal TGR5 and the promotion of ASBT translocation to the plasma membrane, thus affecting BA transport. Next, the increased level of circulating BAs entered the periphery, which might facilitate lipolysis and energy consumption by activating TGR5 in iWAT. ConclusionOur results demonstrated that RGS significantly alleviated HFD-induced obesity and insulin resistance in mice. RGS intervention improved glucose metabolism, promoted lipolysis, and energy metabolism by activating TGR5 in the intestine. In addition, we found that activating intestinal TGR5 facilitated the localization of ASBT to the plasma membrane, which ultimately promoted the transport of BAs to regulate metabolic phenotype.

Determination of Optimal Vitamin D Dosage in Children with Cholestasis

BackgroundVitamin D deficiency in patients with cholestasis is due to impaired intestinal vitamin D absorption, which results from decreased intestinal bile acid concentration. Patients with cholestasis usually do not achieve optimal vitamin D status when a treatment regimen for children without cholestasis is used. However, data on high-dose vitamin D treatment in patients with cholestasis are limited.MethodsThis study is a prospective study that included pediatric patients with cholestasis (serum direct bilirubin > 1 mg/dL) who had vitamin D deficiency (serum 25-hydroxyvitamin D, 25-OHD, < 20 ng/mL). In Phase 1, single-day oral loading of 300,000 IU (or 600,000 IU if weight ≥ 20 kg) of vitamin D2 was administered, followed by an additional loading if serum 25-OHD < 30 ng/mL, and 4-week continuation of treatment using a vitamin D2 dose calculated based on the increment of 25-OHD after first loading. In Phase 2, oral vitamin D2 (200,000 IU/day) was administered for 12 days, followed by 400,000 IU/day of vitamin D2 orally for another 8 weeks if serum 25-OHD < 30 ng/mL.ResultsPhase 1: Seven patients were enrolled. Three out of seven patients had a moderate increase in serum 25-OHD after loading (up to 20.3–27.2 ng/mL). These patients had conditions with partially preserved bile flow. The remaining four patients, who had biliary atresia with failed or no Kasai operation, had low increments of serum 25-OHD. Phase 2: Eleven patients were enrolled. Eight out of 11 patients had a moderate increase in serum 25-OHD after 200,000 IU/day of vitamin D2 for 12 days. Serum 25-OHD continued increasing after administering 400,000 IU/day of vitamin D2 for another 8 weeks, with maximal serum 25-OHD of 15.7–22.8 ng/mL.ConclusionVery high doses of vitamin D2 (200,000 and 400,000 IU/day) partly overcame poor intestinal vitamin D absorption and resulted in moderate increases in serum 25-OHD in pediatric patients with cholestasis, particularly when cholestasis was caused by uncorrectable bile duct obstruction.

Detection of bile acids in bronchoalveolar lavage fluid defines the inflammatory and microbial landscape of the lower airways in infants with cystic fibrosis

BackgroundCystic Fibrosis (CF) is a genetic condition characterized by neutrophilic inflammation and recurrent infection of the airways. How these processes are initiated and perpetuated in CF remains largely unknown. We have demonstrated a link between the intestinal microbiota-related metabolites bile acids (BA) and inflammation in the bronchoalveolar lavage fluid (BALF) from children with stable CF lung disease. To establish if BA indicate early pathological processes in CF lung disease, we combined targeted mass spectrometry and amplicon sequencing-based microbial characterization of 121 BALF specimens collected from 12-month old infants with CF enrolled in the COMBAT-CF study, a multicentre randomized placebo-controlled clinical trial comparing azithromycin versus placebo. We evaluated whether detection of BA in BALF is associated with the establishment of the inflammatory and microbial landscape of early CF lung disease, and whether azithromycin, a motilin agonist that has been demonstrated to reduce aspiration of gastric contents, alters the odds of detecting BA in BALF. We also explored how different prophylactic antibiotics regimens impact the early life BALF microbiota.ResultsDetection of BA in BALF was strongly associated with biomarkers of airway inflammation, more exacerbation episodes during the first year of life, increased use of oral antibiotics with prolonged treatment periods, a higher degree of structural lung damage, and distinct microbial profiles. Treatment with azithromycin, a motilin agonist, which has been reported to reduce aspiration of gastric contents, did not reduce the odds of detecting BA in BALF. Culture and molecular methods showed that azithromycin does not alter bacterial load or diversity in BALF. Conversely, penicillin-type prophylaxis reduced the odds of detecting BAs in BALF, which was associated with elevated levels of circulating biomarkers of cholestasis. We also observed that environmental factors such as penicillin-type prophylaxis or BAs detection were linked to distinct early microbial communities of the CF airways, which were associated with different inflammatory landscapes but not with structural lung damage.ConclusionsDetection of BA in BALF portend early pathological events in CF lung disease. Benefits early in life associated with azithromycin are not linked to its antimicrobial properties.AFd3CvqLfCjKZ9n4H93NFTVideo

Aflatoxin B1 induces liver injury by disturbing gut microbiota-bile acid-FXR axis in mice.

Aflatoxin B1 (AFB1) is one of major pollutant in food and feed worldwide. The purpose of this study is to investigate the mechanism of AFB1-induced liver injury. Our results showed that AFB1 caused hepatic bile duct proliferation, oxidative stress, inflammation and liver injury in mice. AFB1 exposure induced gut microbiota dysbiosis and reduced fecal bile salt hydrolase (BSH) activity. AFB1 exposure promoted hepatic bile acid (BA) synthesis and changed intestinal BA metabolism, especially increased intestinal conjugated bile acids levels. AFB1 exposure inhibited intestinal farnesoid X receptor (FXR)/fibroblast growth factor 15 (FGF-15) signaling. Furthermore, the mice received fecal microbiota transplantation from AFB1-treated mice induced liver injury, reduced intestinal FXR signaling and increased hepatic BA synthesis. Finally, the intestine-restricted FXR agonist treatment decreased hepatic BA synthesis, ROS level, inflammation and liver injury in AFB1-treated mice. This study suggests that modifying the gut microbiota, altering intestinal BA metabolism and/or activating intestinal FXR/FGF-15 signaling may be of value for the treatment of AFB1-induced liver disease.

FRI-333 - Combination of intestinal bile salt uptake inhibition with pharmacological repression of bile salt synthesis improves liver health in cholestatic mice

FRI-333 - Combination of intestinal bile salt uptake inhibition with pharmacological repression of bile salt synthesis improves liver health in cholestatic mice

Bacteroides dorei BDX-01 alleviates DSS-induced experimental colitis in mice by regulating intestinal bile salt hydrolase activity and the FXR-NLRP3 signaling pathway.

Background: The relationships among intestinal dysbiosis, bile acid (BA) metabolism disorders, and ulcerative colitis pathogenesis are now recognized. However, how specific strains regulate BA metabolism to alleviate colitis is still unclear. This study investigated the effects of Bacteroides dorei on the development of acute colitis and elucidated the underlying mechanisms. Methods: The safety of BDX-01 was evaluated in vitro and in vivo. 2.5% dextran sulfate sodium (DSS) induced colitis in C57BL/6 mice, Caco-2, and J774A.1 cells were used to evaluate the anti-inflammatory effect of BDX-01. qPCR and Western blotting were used to detect the expression of inflammatory pathways. Microbiota composition was analyzed by 16S rRNA gene sequencing. Enzyme activity analysis and targeted metabolomics were used to analyze fecal bile salt hydrolase (BSH) and BA levels. Antibiotic-induced pseudo-germ-free mice were used to investigate the role of gut microbiota in the alleviation of colitis by BDX-01. Results: We confirmed the safety of novel strain Bacteroides dorei BDX-01 in vitro and in vivo. Oral BDX-01 administration significantly ameliorated the symptoms and pathological damage of DSS-induced acute colitis. Moreoever, 16S rRNA sequencing and enzyme activity analysis showed that BDX-01 treatment increased intestinal BSH activity and the abundance of bacteria harboring this enzyme. Targeted metabolomics revealed that BDX-01 significantly increased intestinal BA excretion and deconjugation. Certain BAs act as FXR agonists. The β-muricholic acid (βMCA): taurine β-muricholic acid (T-βMCA) and cholic acid (CA): taurocholic acid (TCA) ratios and the deoxycholic acid (DCA) level decreased markedly in the colitis models but increased substantially in BDX-01-treated mice. The colonic farnesoid X receptor (FXR) and fibroblast growth factor 15 (FGF15) were upregulated in mice treated with BDX-01. BDX-01 downregulated the expression of colonic proinflammatory cytokines pyrin domain-containing 3 (NLRP3), ASC, cleaved caspase-1, and IL-1β. Antibiotic treatment didn't abolish the protective effect of BDX-01 on colitis. In vitro studies showed TβMCA abolished the effects of BDX-01 on FXR activation and inhibition of the NLRP3 inflammasome activation. Conclusion: BDX-01 improved DSS-induced acute colitis by regulating intestinal BSH activity and the FXR-NLRP3 signaling pathway. Our findings indicate that BDX-01 is a promising probiotic to improve the management of ulcerative colitis.

Proteomic Characterization of Human Gut Habitual Bacteroides intestinalis against Common Intestinal Bile Acid Stress

Bacteroides intestinalis (B. intestinalis) is an abundant gastrointestinal commensal bacterium and is able to produce secondary bile acids (BAs) among other important metabolic functions. However, deoxycholic acid (DCA) is known to suppress Bacteroides, suggesting differential molecular impact of different BA species on Bacteroides. Among major human gastrointestinal BA components, we first demonstrated that DCA and chenodeoxycholic acid (CDCA) and their taurine-conjugated species at 1 mM showed significantly higher inhibitory effects on the growth of B. intestinalis than cholic acid (CA) and lithocholic acid (LCA) and their taurine-conjugated species. Then, high-throughput proteomic strategy was used to show that both TCDCA and TDCA caused more proteome-wide modulation than TCA and TLCA. In response to incremental BA toxicity, the main functional changes of B. intestinalis include enhanced protein synthesis, DNA integrity maintenance, and suppressed central metabolic activities. Importantly, key energy and BA metabolism enzymes of B. intestinalis were inhibited by TCDCA and TDCA. These findings provide a basis for future studies to explore how Bacteroides respond to bile stress and how BA composition modulate gut microbiome homeostasis.

Chronic corticosterone exposure disrupts hepatic and intestinal bile acid metabolism in chicken.

Chronic stress leads to a high circulating level of glucocorticoids, which disrupts lipid metabolism and causes non-alcoholic fatty liver disease in mice and humans. Meanwhile, bile acid (BA), a class of metabolites initially synthesized in the liver and further metabolized by gut microbiota, plays a vital role in lipid metabolism. This study aimed to investigate the effects of glucocorticoids on BA metabolism and gut microbiota in chickens. In this study, 35-day-old chickens were injected with 4 mg/kg/day corticosterone (Cort) for 14 days to simulate chronic stress. Cort treatment significantly increased the triglyceride contents in the plasma and the liver. HE and oil-red staining showed that Cort treatment induced fatty liver in chickens. Meanwhile, Cort exposure downregulated total bile acid (TBA) content in the liver while increasing the TBA in feces. UPLC-HRMS results showed that Cort exposure significantly decreased the hepatic levels of CDCA, T-alpha-MCA, and T-beta-MCA. Moreover, Cort exposure significantly reduced the expression of genes related to BA synthesis (CYP8B1 and CYP27A1), conjugation (BACS), and regulation (KLβ and FGFR4). 16s sequencing results showed that Cort treatment significantly decreased the amount of Lachnospiraceae, Eisenbergiella, Blautia, and Eubacterium and increased the abundance of Barnesiella, Lactobacillus, and Helicobacter. Spearman correlation analysis showed a significant positive correlation between fecal TBA and the abundance of Lactobacillales, Lactobacillus, and Barnesiella. In comparison, TBA in the liver was positively correlated with Eubacterium, and negatively correlated with Helicobacter. In summary, chronic Cort exposure disrupts hepatic and intestinal bile acid metabolism inducing gut microbiome dysbiosis, which might associate with the development of fatty liver in chickens.

Glycine-β-Muricholic Acid Improves Liver Fibrosis and Gut Barrier Function by Reducing Bile Acid Pool Size and Hydrophobicity in Male Cyp2c70 Knockout Mice.

Cyp2c70 knockout mice lack the enzyme that produces muricholic acids and show a "human-like" hydrophobic bile acid pool-induced hepatobiliary injury. In this study, we investigated the potential anti-cholestasis effect of glycine-conjugated β muricholic acid (G-β-MCA) in male Cyp2c70 KO mice based on its hydrophilic physiochemical property and signaling property as an farnesoid X receptor (FXR) antagonist. Our results showed that G-β-MCA treatment for 5 weeks alleviated ductular reaction and liver fibrosis and improved gut barrier function. Analysis of bile acid metabolism suggested that exogenously administered G-β-MCA was poorly absorbed in the small intestine and mostly deconjugated in the large intestine and converted to taurine-conjugated MCA (T-MCA) in the liver, leading to T-MCA enrichment in the bile and small intestine. These changes decreased the biliary and intestine bile acid hydrophobicity index. Furthermore, G-β-MCA treatment decreased intestine bile acid absorption via unknown mechanisms, resulting in increased fecal bile acid excretion and a reduction in total bile acid pool size. In conclusion, G-β-MCA treatment reduces the bile acid pool size and hydrophobicity and improves liver fibrosis and gut barrier function in Cyp2c70 KO mice.

Supplementation of microencapsulated probiotics modulates gut health and intestinal microbiota.

The beneficial effect of probiotics on host health is impaired due to the substantial loss of survivability during gastric transit caused by small intestinal enzymes and bile acids. Encapsulation helps to preserve the probiotics species from severe environmental factors. Lactobacillus paracasei, highly sensitive probiotic species to gastric acid, was encapsulated with polyacrylate resin. C57BL/6 male mice were equally divided into three groups; control group was fed with basal diet without any additives, the un-encapsulated group was fed with 0.1% of a mixture of encapsulating material and L. paracasei, and encapsulated group was fed with 0.1% encapsulated L. paracasei (microcapsule) for 4 weeks. The result showed elevated fecal moisture percentage in the encapsulated group, but not in the un-encapsulated group. Further study showed that the ratio of villus height to crypt depth in the small intestine was significantly higher compared to un-encapsulated and the control group. Microencapsulated probiotics also remarkably increased intestinal mucin and secretory immunoglobulin A (sIgA) concentration, intestinal MUC-2, and tight junction protein mRNA expression levels improving the intestinal barrier function of mice. In addition, microcapsules also reduced proinflammatory factor mRNA expression, while considerably increasing anti-inflammatory factor mRNA expression. Microbiota metabolites, fecal LPS (Lipopolysaccharide) were downregulated, and acetate and lactate were upraised compared to control. Furthermore, glutathione peroxidase (GSH-Px) and TAOC levels were increased and Malondialdehyde (MDA) was decreased improving antioxidant capacity. Microflora and bioinformatic predictive analysis of feces showed that encapsulated probiotics remarkably increased Lactobacillus proportions. Mice's intestinal health can thus be improved by using microencapsulated probiotics.

KALP BAĞIRSAK EKSENİ

Many interactions play a role in the gut-heart axis. These include intestinal epithelial dysfunction, dysbiosis, butyrate-producing bacteria, bile acids, and intestinal microbe-derived metabolites. In patients with heart failure (HF), mucosal malabsorption, intestinal wall edema and barrier dysfunction develop as a result of microcirculation disorders in the gut due to decreased perfusion, increased congestion and sympathetically mediated vasoconstriction. Toxic, pathogenic, immunogenic and inflammatory factors, through the increase in intestinal permeability as a result of damaged tight junctions in the intestine, pass through the mucosa and reach the systemic circulation, causing local-systemic inflammation. Many factors that cause dysbiosis by changing the intestinal flora, which are frequently seen in HF, lead to bacterial overgrowth, bacterial translocation and formation of many toxic substances, including lipopolysaccharide (LPS), trimethylamine N-oxide (TMAO), p-cresylsulfate (PCS) and indoxyl sulfate (IS). Depending on the increase in intestinal permeability, these toxic substances reach the systemic circulation; it increases the risk of atherosclerosis by playing a role in thrombosis, platelet invasion, foam cell formation and inflammation processes. Decreased levels of butyrate, one of the short-chain fatty acids that have many effects on the gastrointestinal tract, including maintaining intestinal barrier integrity; It promotes foam cell formation, exacerbates dysbiosis, and plays a role in the disruption of intestinal barrier function, causing endotoxins to reach the general circulation. With this review, it is aimed to inform about the physiopathological processes in the gut-heart axis, in the light of the current literature.

Lactobacillus fermentum MCC2760 abrogate high-fat induced perturbations in the enterohepatic circulation of bile acids in rats

This study in hyperlipidemic rats elucidated the effect of Lactobacillus fermentum MCC2760 on intestinal bile acid (BA) uptake, hepatic BA synthesis, and enterohepatic BA transporters. Diets rich in saturated fatty acids [coconut oil (CO)] and omega-6 fatty acids [sunflower oil (SFO)] at 25g fat/100g diet were fed to rats with or without MCC2760 (109 cells/kg body weight). After 60days of feeding, intestinal BA uptake and expression of Asbt, Osta/b mRNA and protein, and hepatic expression of Ntcp, Bsep, Cyp7a1, Fxr, Shp, Lrh-1, and Hnf4a mRNA were measured. Hepatic expression of HMG-CoA reductase protein and its activity and total BAs in serum, liver, and feces were assessed. Hyperlipidaemic groups (HF-CO and HF-SFO) had: 1) increased intestinal BA uptake, Asbt and Osta/b mRNA expression, and ASBT staining 2) increased BA in serum, 3) decreased hepatic expression of Ntcp, Bsep, and Cyp7a1 mRNA, and NTCP staining 4) increased activity of HMG-CoA reductase, 5) increased hepatic expression of Fxr and Shp mRNA, 6) decreased hepatic expression of Lrh-1 and Hnf4a mRNA, and 7) decreased BA in Feces when compared to their respective controls (N-CO and N-SFO) and experimental groups (HF-CO+LF and HF-SFO+LF). Immunostaining revealed increased intestinal Asbt and hepatic Ntcp protein expression in the HF-CO and HF-SFO groups compared to control and experimental groups. Incorporating probiotics like MCC2760 abrogated hyperlipidemia-induced changes in the intestinal uptake, hepatic synthesis, and enterohepatic transporters of BA in rats. Probiotic MCC2760 can be used to modulate lipid metabolism in high-fat-induced hyperlipidemic conditions.

Intestinal bile acids provide a surmountable barrier against C. difficile TcdB-induced disease pathogenesis

Intestinal bile acids play an essential role in the Clostridioides difficile lifecycle having been shown invitro to modulate various aspects of pathogenesis, including spore germination, vegetative growth, and more recently the action of the primary virulence determinant, TcdB. Here, we investigated whether physiological levels of the total pool of intestinal bile acids in mice and humans protect against TcdB action. Small molecules extracted from the lumenal contents of the small intestine, cecum, colon, and feces were found to inhibit TcdB in accordance with the differential amounts of total bile acids in each compartment. Extracts from antibiotic-treated and germ-free mice, despite harboring dramatically altered bile acid profiles, unexpectedly also prevented TcdB-induced cell rounding to similar extents. We show that protection, however, is surmountable and can be overcome at higher doses of TcdB-typical to those seen during severe C.difficile infection-suggesting that the protective properties of intestinal bile acids are operant primarily under low to moderate toxin levels. Taken together, these findings demonstrate a role for intestinal bile acids in attenuating virulence, provide insights into asymptomatic carriage of toxigenic C. difficile, and inform strategies to manipulate bile acid levels for therapeutic benefit.

Prevention of High-Fat-Diet-Induced Dyslipidemia byLactobacillus plantarumLP104 through Mediating Bile Acid Enterohepatic Axis Circulation and Intestinal Flora

This work aimed to investigate the alleviative mechanism of Lactobacillus plantarum LP104 (LP104) isolated from kimchi on high-fat-diet-induced dyslipidemia by targeting the intestinal flora and bile acid (BA) metabolism. Oral administration of LP104 over 8 weeks reduced body weight gain and body fat, as well as ameliorating serum and hepatic dyslipidemia in HFD-fed C57BL/6N mice significantly. LP104 intervention also increased the ileal tauro-α/β-muricholic acid sodium salt (T-α-MCA or T-β-MCA) and tauroursodeoxycholic acid (TUDCA) concentrations to suppress the enterohepatic farnesoid X receptor/fibroblast growth factor 15-fibroblast growth factor receptor 4 (FXR/FGF15-FGFR4) signaling pathway, which stimulated the hepatic cholic acid (CA) and chenodeoxycholic acid (CDCA) de novo synthesis through using cholesterol. Then, LP104 treatment accelerated BA excretion with the feces and cholesterol efflux to improve HFD-caused hyperlipidemia effectively. The 16S rRNA gene high-throughput sequencing revealed that LP104 promoted intestinal flora rebalance by increasing the abundances of Bacteroides, Akkermansia, Lactobacillus, and Clostridium and decreasing the abundance of Oscillospira and Coprococcus. Meanwhile, Spearman correlation analysis demonstrated that the differential flora were closely related to BA signaling molecules including CA, CDCA, T-α-MCA, T-β-MCA, and TUDCA after LP104 intervention. These findings provided new evidence that LP104 had the potential to be used as a naturally functional food for the prevention of dyslipidemia.

Apple-derived extracellular vesicles modulate the expression of human intestinal bile acid transporter ASBT/SLC10A2 via downregulation of transcription factor RARα

PurposePlant-derived extracellular vesicles (EVs) have been reported to exert biological activity on intestinal tissues by delivering their contents into intestinal cells. We previously reported that ASBT/SLC10A2 mRNA was downregulated by apple-derived extracellular vesicles (APEVs). ASBT downregulation is effective in the treatment of cholestasis and chronic constipation, similar to the beneficial effects of apples. Therefore, this study aimed to establish the mechanism of ASBT downregulation by APEVs, focusing on microRNAs present in APEVs. ResultsAPEVs downregulated the expression of ASBT, but no significant effect on SLC10A2-3′UTR was observed. Proteomics revealed that APEVs decreased the expression of RARα/NR1B1. The binding of RARα to SLC10A2 promoter was also decreased by APEVs. The stability of NR1B1 mRNA was attenuated by APEVs and its 3′UTR was found to be a target for APEVs. Apple microRNAs that were predicted to interact with NR1B1-3′UTR were present in APEVs, and their mimics suppressed NR1B1 mRNA expression. ConclusionsSuppression of ASBT by APEVs was indirectly mediated by the downregulation of RARα, and its stability was lowered by microRNAs present in APEVs. This study suggested that macromolecules in food directly affect intestinal function by means of EVs that stabilize them and facilitate their cellular uptake.

Berberine is a potential alternative for metformin with good regulatory effect on lipids in treating metabolic diseases

Metformin (MTF) and berberine (BBR) share several therapeutic benefits in treating metabolic-related disorders. However, as the two agents have very different chemical structure and bioavailability in oral route, the goal of this study is to learn their characteristics in treating metabolic disorders. The therapeutic efficacy of BBR and MTF was systemically investigated in the high fat diet feeding hamsters and/or ApoE(-/-) mice; in parallel, gut microbiota related mechanisms were studied for both agents. We discovered that, although both two drugs had almost identical effects on reducing fatty liver, inflammation and atherosclerosis, BBR appeared to be superior over MTF in alleviating hyperlipidemia and obesity, but MTF was more effective than BBR for the control of blood glucose. Association analysis revealed that the modulation of intestinal microenvironment played a crucial role in the pharmacodynamics of both drugs, in which their respective superiority on the regulation of gut microbiota composition and intestinal bile acids might contribute to their own merits on lowering glucose or lipids. This study shows that BBR may be a good alternative for MTF in treating diabetic patients, especially for those complicated with dyslipidemia and obesity.

Investigation of therapeutic effects of rhubarb decoction retention enema on minimal hepatic encephalopathy in rats based on 16S rDNA gene sequencing and bile acid metabolomics

Minimal hepatic encephalopathy (MHE) is an early stage of hepatic encephalopathy (HE), with high incidence and a high rate of clinically missed diagnosis. Early diagnosis of MHE and effective clinical intervention are of great importance. Rhubarb decoction (RD)-induced retention enema can effectively improve the cognitive function of patients with MHE, whereas disturbances in the enterohepatic circulation of bile acid (BAs) can induce MHE. However, the molecular mechanisms underlying the therapeutic effects of RD have not been examined from the perspective of intestinal microbiota and bile metabolomics. In this study, we investigated the effects of RD-induced retention enema on intestinal microbiota and bile metabolites in rats with CCl4- and TAA-induced MHE. RD-induced retention enema significantly improved liver function, reduced blood ammonia levels, alleviated cerebral oedema and restored cognitive function in rats with MHE. In addition, it increased the abundance of intestinal microbes; partially reversed the disorder in the composition of intestinal microbiota, including the Bifidobacterium and Bacteroides genera; and regulated BA metabolism, such as taurine combined with increased BA synthesis. In conclusion, this study highlights the potential importance of BA enterohepatic circulation for RD to improve cognitive function in MHE rats, providing a new perspective on the mechanism of this herb. The findings of this study will facilitate experimental research on RD and help to develop RD-based strategies for clinical application.