Ursodeoxycholic acid accelerates bile acid enterohepatic circulation

Tauroursodeoxycholic Acid Improves Nonalcoholic Fatty Liver Disease by Regulating Gut Microbiota and Bile Acid Metabolism

Tauroursodeoxycholic acid (TUDCA) is a synthetic bile salt that has demonstrated efficacy in the management of hepatobiliary disorders. However, its specific mechanism of action in preventing and treating nonalcoholic fatty liver disease (NAFLD) remains incompletely understood. This research revealed that TUDCA treatment can reduce obesity and hepatic lipid buildup, enhance intestinal barrier function and microbial balance, and increase the presence of Allobaculum and Bifidobacterium in NAFLD mouse models. TUDCA can influence the activity of farnesoid X receptor (FXR) and cholesterol 7α-hydroxylase (CYP7A1), resulting in higher hepatic bile acid levels and increased expression of sodium taurocholate cotransporting polypeptide (NTCP), leading to elevated concentrations of liver-bound bile acids in mice. Furthermore, TUDCA can inhibit the expression of FXR and fatty acid transport protein 5 (FATP5), thereby reducing fatty acid absorption and hepatic lipid accumulation. This investigation provides new insights into the potential of TUDCA for preventing and treating NAFLD.

Antioxidant Role of Probiotics in Inflammation-Induced Colorectal Cancer

Colorectal cancer (CRC) continues to be a significant contributor to global morbidity and mortality. Emerging evidence indicates that disturbances in gut microbial composition, the formation of reactive oxygen species (ROS), and the resulting inflammation can lead to DNA damage, driving the pathogenesis and progression of CRC. Notably, bacterial metabolites can either protect against or contribute to oxidative stress by modulating the activity of antioxidant enzymes and influencing signaling pathways that govern ROS-induced inflammation. Additionally, microbiota byproducts, when supplemented through probiotics, can affect tumor microenvironments to enhance treatment efficacy and selectively mediate the ROS-induced destruction of CRC cells. This review aims to discuss the mechanisms by which taxonomical shifts in gut microbiota and related metabolites such as short-chain fatty acids, secondary bile acids, and trimethylamine-N-oxide influence ROS concentrations to safeguard or promote the onset of inflammation-mediated CRC. Additionally, we focus on the role of probiotic species in modulating ROS-mediated signaling pathways that influence both oxidative status and inflammation, such as Nrf2-Keap1, NF-κB, and NLRP3 to mitigate carcinogenesis. Overall, a deeper understanding of the role of gut microbiota on oxidative stress may aid in delaying or preventing the onset of CRC and offer new avenues for adjunct, CRC-specific therapeutic interventions such as cancer immunotherapy.

Safety assessment of enzymatically converted chicken bile as a novel food material: Genotoxicity, teratogenicity, and acute and subchronic toxicity studies

Enzymatically converted chicken bile (CB), prepared by converting taurine deoxycholic acid (TCDCA) to taurine ursodeoxycholic acid (TUDCA) in CB, possesses various functional activities. But their nutrient composition and safety assessment have not been fully investigated yet. CB was mainly composed of proteins and steroids. CB did not show genotoxic effects based on Ames test, mammalian erythrocyte micronucleus test, and in vitro mammalian chromosomal aberration test. There were no growth abnormalities or deaths in the acute toxicity test for mice, indicating that CB is nontoxic with an LD50 > 10 g/kg·body weight (BW). Subchronic toxicity test and genotoxicity test were performed based on intake of 0.5 g CB per person daily at expanded doses of 33.3, 100, and 300 times (278, 833, and 2500 mg/kg·BW). The result indicated that CB at 833 mg/kg·BW showed no toxicity on BW, body weight gain, food intake, hematological, serum biochemistry, absolute/relative organ weights, urinalysis, and pathological features of rats in the subchronic toxicity test, while CB at 833 mg/kg·BW induced maternal toxicity with no fetus teratogenicity or embryotoxicity in the teratogenicity test. In conclusion, CB did not show toxic effects and a long-term daily intake of CB at 0.5 g per person is considered safe, but pregnant women should avoid it. These findings could provide a reference for the safe use of CB in functional food.

Regulating the absorption and excretion of perfluorooctane sulfonate and its alternatives through influencing enterohepatic circulation

Enterohepatic circulation has been reported to play a significant role in the bioaccumulation of PFASs. In this study, the tissue distribution and excretion of PFOS and its alternatives, namely 6:2 and 8:2 fluorotelomer sulfonic acid (FTSA) was investigated using a mouse assay with a focus on role of enterohepatic circulation. Liver was the primarily accumulating organ for PFOS and 8:2 FTSA (33.4 % and 25.8 % of total doses absorbed after 14 days), whereas 65 % of 6:2 FTSA was excreted via urine within 24 h. Peak levels of 8:2 FTSA and PFOS were found in the gallbladder, implying the important role of enterohepatic circulation in PFASs reabsorption. The role of enterohepatic circulation was further evaluated through co-exposure of 8:2 FTSA and PFOS with medicines (namely metformin (MET) and ursodeoxycholic acid (UDCA)). MET reduced accumulation of 8:2 FTSA and PFOS in the liver by 68.6 % and 65.8 %, through down-regulation of bile acid transporter (Asbt) and enhancement of fecal excretion. Conversely, UDCA raised their concentrations by 21.9 % and 34.6 % compared to that exposed solely to PFASs. A strong positive correlation was identified between PFASs serum levels and Asbt expression. This study illuminated PFAS bioaccumulation mechanisms and suggested potential strategies to mitigate the exposure risks.

Characterization of individual bile acids in vivo utilizing a novel low bile acid mouse model

Bile acids (BAs) are signaling molecules synthesized in the liver initially by CYP7A1 and CYP27A1 in the classical and alternative pathways, respectively. BAs are essential for cholesterol clearance, intestinal absorption of lipids, and endogenous modulators of farnesoid x receptor (FXR). FXR is critical in maintaining BA homeostasis and gut-liver crosstalk. Complex reactions in vivo and the lack of suitable animal models impede our understanding of the functions of individual BAs. In this study, we characterized the in vivo effects of three-day feeding of cholic acid (CA), deoxycholic acid (DCA), or ursodeoxycholic acid (UDCA) at physiological/non-hepatotoxic concentrations in a novel low-BA mouse model (Cyp7a1-/-/Cyp27a1-/-, DKO). Liver injury, BA levels and composition and BA signaling by the FXR-fibroblast growth factor 15 (FGF15) axis were determined. Overall, higher basal inflammation and altered lipid metabolism in DKO mice might be associated with low BAs. CA, DCA, and UDCA feeding activated FXR signals with tissue specificity. Dietary CA and DCA similarly altered tissue BA profiles to be less hydrophobic, while UDCA promoted a more hydrophobic tissue BA pool with the profiles shifted toward non-12α-OH BAs and secondary BAs. However, UDCA did not offer any overt protective effects as expected. These findings allow us to determine the precise effects of individual BAs in vivo on BA-FXR signaling and overall BA homeostasis in liver physiology and pathologies.

A prognostic model established using bile acid genes to predict the immunity and survival of patients with gastrointestinal cancer

BACKGROUND

The metabolism of abnormal bile acids (BAs) is implicated in the initiation and development of gastrointestinal (GI) cancer. However, there was a lack of research on the molecular mechanisms of BAs metabolism in GI.

METHODS

Genes involved in BAs metabolism were excavated from public databases of The Cancer Genome Atlas (TCGA) database, Gene Expression Omnibus (GEO) database, and Molecular Signatures Database (MSigDB). ConsensusClusterPlus was used to classify molecular subtypes for GI. To develop a RiskScore model for predicting GI prognosis, univariate Cox analysis was performed on the genes in protein-protein interaction (PPI) network, followed by using Lasso regression and stepwise regression to refine the model and to determine the key prognostic genes. Tumor immune microenvironment in GI patients from different risk groups was assessed using the ESTIMATE algorithm and enrichment analysis. Reverse transcription-quantitative real-time PCR (RT-qPCR), Transwell assay, and wound healing assay were carried out to validate the expression and functions of the model genes.

RESULTS

This study defined three molecular subtypes (C1, C2, and C3). Specifically, C1 had the best prognosis, while C3 had the worst prognosis with high immune checkpoint gene expression levels and TIDE scores. We selected nine key genes (AXIN2, ATOH1, CHST13, PNMA2, GYG2, MAGEA3, SNCG, HEYL, and RASSF10) that significantly affected the prognosis of GI and used them to develop a RiskScore model accordingly. Combining the verification results from a nomogram, the prediction of the model was proven to be accurate. The high RiskScore group was significantly enriched in tumor and immune-related pathways. Compared with normal gastric mucosal epithelial cells, the mRNA levels of the nine genes were differential in the gastric cancer cells. Inhibition of PNMA2 suppressed migration and invasion of the cancer cells.

CONCLUSION

We distinguished three GI molecular subtypes with different prognosis based on the genes related to BAs metabolism and developed a RiskScore model, contributing to the diagnosis and treatment of patients with GI.

Aromatic Amino Acids Promote Lipid Metabolism Disorders by Increasing Hepatic Bile Acid Synthesis

BACKGROUND

Obesity is a progressive metabolic disease that begins with lipid metabolism disorders. Aromatic amino acids (AAAs), including tryptophan, phenylalanine, and tyrosine, have diverse biological activities as nutrients. However, the underlying mechanisms by which AAAs affect lipid metabolism are unclear.

OBJECTIVES

This study was designed to investigate the possible roles and underlying molecular mechanisms of AAA in the pathogenesis of lipid metabolism disorders.

METHODS

We added an AAA mixture to the high-fat diet (HFD) of mice. Glucose tolerance test was recorded. Protein expression of hepatic bile acid (BA) synthase and mRNA expression of BA metabolism-related genes were determined. Hepatic BA profiles and gut microbial were also determined in mice.

RESULTS

The results showed that AAA significantly increased body weight and white adipose tissue, aggravated liver injury, impaired glucose tolerance and intestinal integrity, and significantly increased hepatic BA synthesis by inhibiting intestinal farnesoid X receptor (FXR). Moreover, AAA increased the content of total BA in the liver and altered the hepatic BA profile, with elevated levels of lithocholic acid, glycochenodeoxycholic acid, and glycoursodeoxycholic acid. AAA markedly increased the levels of proteins involved in BA synthesis (cholesterol 7α-hydroxylase and oxysterol 7α-hydroxylase) and inhibited the intestinal FXR. Gut microbial composition also changed, reducing the abundance of some beneficial bacteria, such as Parvibacter and Lactobacillus.

CONCLUSIONS

Under HFD conditions, AAAs stimulate BA synthesis in both the classical and alternative pathways, leading to aggravation of liver injury and fat deposition. Excessive intake of AAA disrupts BA metabolism and contributes to the development of lipid metabolism disorders, suggesting that AAA may be a causative agent of lipid metabolism disorders.

Determination of Bile Acids in Canine Biological Samples: Diagnostic Significance

The comprehensive examination of bile acids is of paramount importance across various fields of health sciences, influencing physiology, microbiology, internal medicine, and pharmacology. While enzymatic reaction-based photometric methods remain fundamental for total BA measurements, there is a burgeoning demand for more sophisticated techniques such as liquid chromatography-tandem mass spectrometry (LC-MS/MS) for comprehensive BA profiling. This evolution reflects a need for nuanced diagnostic assessments in clinical practice. In canines, a BA assessment involves considering factors, such as food composition, transit times, and breed-specific variations. Multiple matrices, including blood, feces, urine, liver tissue, and gallbladder bile, offer insights into BA profiles, yet interpretations remain complex, particularly in fecal analysis due to sampling challenges and breed-specific differences. Despite ongoing efforts, a consensus regarding optimal matrices and diagnostic thresholds remains elusive, highlighting the need for further research. Emphasizing the scarcity of systematic animal studies and underscoring the importance of ap-propriate sampling methodologies, our review advocates for targeted investigations into BA alterations in canine pathology, promising insights into pathomechanisms, early disease detection, and therapeutic avenues.

Altered microbial bile acid metabolism exacerbates T cell-driven inflammation during graft-versus-host disease

Microbial transformation of bile acids affects intestinal immune homoeostasis but its impact on inflammatory pathologies remains largely unknown. Using a mouse model of graft-versus-host disease (GVHD), we found that T cell-driven inflammation decreased the abundance of microbiome-encoded bile salt hydrolase (BSH) genes and reduced the levels of unconjugated and microbe-derived bile acids. Several microbe-derived bile acids attenuated farnesoid X receptor (FXR) activation, suggesting that loss of these metabolites during inflammation may increase FXR activity and exacerbate the course of disease. Indeed, mortality increased with pharmacological activation of FXR and decreased with its genetic ablation in donor T cells during mouse GVHD. Furthermore, patients with GVHD after allogeneic hematopoietic cell transplantation showed similar loss of BSH and the associated reduction in unconjugated and microbe-derived bile acids. In addition, the FXR antagonist ursodeoxycholic acid reduced the proliferation of human T cells and was associated with a lower risk of GVHD-related mortality in patients. We propose that dysbiosis and loss of microbe-derived bile acids during inflammation may be an important mechanism to amplify T cell-mediated diseases.

Involvement of Bile Acid Metabolism and Gut Microbiota in the Amelioration of Experimental Metabolism-Associated Fatty Liver Disease by Nobiletin

Metabolism-associated fatty liver disease (MAFLD), a growing health problem worldwide, is one of the major risks for the development of cirrhosis and liver cancer. Oral administration of nobiletin (NOB), a natural citrus flavonoid, modulates the gut microbes and their metabolites in mice. In the present study, we established a mouse model of MAFLD by subjecting mice to a high-fat diet (HFD) for 12 weeks. Throughout this timeframe, NOB was administered to investigate its potential benefits on gut microbial balance and bile acid (BA) metabolism using various techniques, including 16S rRNA sequencing, targeted metabolomics of BA, and biological assays. NOB effectively slowed the progression of MAFLD by reducing serum lipid levels, blood glucose levels, LPS levels, and hepatic IL-1β and TNF-α levels. Furthermore, NOB reinstated diversity within the gut microbial community, increasing the population of bacteria that produce bile salt hydrolase (BSH) to enhance BA excretion. By exploring further, we found NOB downregulated hepatic expression of the farnesoid X receptor (FXR) and its associated small heterodimer partner (SHP), and it increased the expression of downstream enzymes, including cholesterol 7α-hydroxylase (CYP7A1) and cytochrome P450 27A1 (CYP27A1). This acceleration in cholesterol conversion within the liver contributes to mitigating MAFLD. The present findings underscore the significant role of NOB in regulating gut microbial balance and BA metabolism, revealing that long-term intake of NOB plays beneficial roles in the prevention or intervention of MAFLD.

Risk factors for recurrence of common bile duct stones after surgical treatment and effect of ursodeoxycholic acid intervention

BACKGROUND

Endoscopic retrograde cholangiopancreatography (ERCP) is an accurate diagnostic method for choledocholithiasis and treatment option for stone removal. Additionally, ursodeoxycholic acid (UDCA) can dissolve cholesterol stones and prevent their development and reappearance by lowering the cholesterol concentration in bile. Despite these treatment options, there are still patients who experience stone recurrence.

AIM

To analyze the risk factors for choledocholithiasis recurrence after ERCP retrograde cholangiopancreatography and the effect of UDCA intervention.

METHODS

The clinical data of 100 patients with choledochal stones who were hospitalized at the Yixing People's Hospital and underwent ERCP for successful stone extraction between June 2020 and December 2022 were retrospectively collected. According to the post-ERCP treatment plan, 100 patients were classified into UDCA (n = 47) and control (n = 53) groups. We aimed to assess the clinical efficacy and rate of relapse in the two patient populations. We then collected information (basic demographic data, clinical characteristics, and serum biochemical indicators) and determined the factors contributing to relapse using logistic regression analysis. Our secondary goal was to determine the effects of UDCA on liver function after ERCP.

RESULTS

Compared to the control group, the UDCA group demonstrated a higher clinical effectiveness rate of 92.45% vs 78.72% (P < 0.05). No significant differences were observed in liver function indices, including total bilirubin, direct bilirubin, gamma-glutamyl transpeptidase, alanine aminotransferase, alkaline phosphatase, and aspartate aminotransferase, between the two groups before treatment. After treatment, all liver function indices were significantly reduced. Comparing the control vs UDCA groups, the UDCA group exhibited significantly lower levels of all indices (55.39 ± 6.53 vs 77.31 ± 8.52, 32.10 ± 4.62 vs 45.39 ± 5.69, 142.32 ± 14.21 vs 189.63 ± 16.87, 112.52 ± 14.25 vs 149.36 ± 15.36, 122.61 ± 16.00 vs 171.33 ± 22.09, 96.98 ± 10.44 vs 121.35 ± 11.57, respectively, all P < 0.05). The stone recurrence rate was lower in the UDCA group (13.21%) in contrast with the control group (44.68%). Periampullary diverticula (OR: 6.00, 95%CI: 1.69-21.30), maximum stone diameter (OR: 1.69, 95%CI: 1.01-2.85), stone quantity >3 (OR: 4.23, 95%CI: 1.17-15.26), and positive bile culture (OR: 7.61, 95%CI: 2.07-27.91) were independent factors that influenced the relapse of common bile duct stones after ERCP (P < 0.05). Furthermore, postoperative UDCA was identified as a preventive factor (OR: 0.07; 95%CI: 0.08-0.09).

CONCLUSION

The intervention effect of UDCA after ERCP for common bile duct stones is adequate, providing new research directions and references for the prevention and treatment of stone recurrence.

Effects of Prevotella copri on insulin, gut microbiota and bile acids

Obesity is becoming a major global health problem in children that can cause diseases such as type 2 diabetes and metabolic disorders, which are closely related to the gut microbiota. However, the underlying mechanism remains unclear. In this study, a significant positive correlation was observed between Prevotella copri (P. copri) and obesity in children (p = 0.003). Next, the effect of P. copri on obesity was explored by using fecal microbiota transplantation (FMT) experiment. Transplantation of P. copri. increased serum levels of fasting blood glucose (p < 0.01), insulin (p < 0.01) and interleukin-1β (IL-1β) (p < 0.05) in high-fat diet (HFD)-induced obese mice, but not in normal mice. Characterization of the gut microbiota indicated that P. copri reduced the relative abundance of the Akkermansia genus in mice (p < 0.01). Further analysis on bile acids (BAs) revealed that P. copri increased the primary BAs and ursodeoxycholic acid (UDCA) in HFD-induced mice (p < 0.05). This study demonstrated for the first time that P. copri has a significant positive correlation with obesity in children, and can increase fasting blood glucose and insulin levels in HFD-fed obese mice, which are related to the abundance of Akkermansia genus and bile acids.

Transcriptomic (DNA Microarray) and Metabolome (LC-TOF-MS) Analyses of the Liver in High-Fat Diet Mice after Intranasal Administration of GALP (Galanin-like Peptide)

The aim of this research was to test the efficacy and potential clinical application of intranasal administration of galanin-like peptide (GALP) as an anti-obesity treatment under the hypothesis that GALP prevents obesity in mice fed a high-fat diet (HFD). Focusing on the mechanism of regulation of lipid metabolism in peripheral tissues via the autonomic nervous system, we confirmed that, compared with a control (saline), intranasally administered GALP prevented further body weight gain in diet-induced obesity (DIO) mice with continued access to an HFD. Using an omics-based approach, we identified several genes and metabolites in the liver tissue of DIO mice that were altered by the administration of intranasal GALP. We used whole-genome DNA microarray and metabolomics analyses to determine the anti-obesity effects of intranasal GALP in DIO mice fed an HFD. Transcriptomic profiling revealed the upregulation of flavin-containing dimethylaniline monooxygenase 3 (Fmo3), metallothionein 1 and 2 (Mt1 and Mt2, respectively), and the Aldh1a3, Defa3, and Defa20 genes. Analysis using the DAVID tool showed that intranasal GALP enhanced gene expression related to fatty acid elongation and unsaturated fatty acid synthesis and downregulated gene expression related to lipid and cholesterol synthesis, fat absorption, bile uptake, and excretion. Metabolite analysis revealed increased levels of coenzyme Q10 and oleoylethanolamide in the liver tissue, increased levels of deoxycholic acid (DCA) and taurocholic acid (TCA) in the bile acids, increased levels of taurochenodeoxycholic acid (TCDCA), and decreased levels of ursodeoxycholic acid (UDCA). In conclusion, intranasal GALP administration alleviated weight gain in obese mice fed an HFD via mechanisms involving antioxidant, anti-inflammatory, and fatty acid metabolism effects and genetic alterations. The gene expression data are publicly available at NCBI GSE243376.

An evaluation of ursodeoxycholic acid treatment in prolonged unconjugated hyperbilirubinemia due to breast milk

Background/Aim

Prolonged jaundice is one of the most common problems during neonatal period. The aim of this study was to evaluate the efficiency of ursodeoxycholic acid (UDCA) treatment in newborn infants with prolonged unconjugated hyperbilirubinemia.

Materials and Methods

The present study included 27 patients who were fed by breast milk and followed up in the outpatient clinic due to prolonged jaundice without any underlying etiological factor; 10 mg/kg/day UDCA was administrated in two doses for 7 days. Furthermore, 20 newborns diagnosed with prolonged jaundice with same characteristics were enrolled as the control group. The control group was also given a placebo; demographic characteristics, liver functions tests before and after the treatment, bilirubin decrease rates, and hemogram parameters of groups were compared.

Results

Total bilirubin levels in the study and control groups before the treatment were 16.02 ± 1.41 mg/dL and 15.93 ± 1.66 mg/dL, respectively (P = 0.84). Total bilirubin levels in the study and control groups at day 7 after UDCA treatment were detected 8.18 ± 2.31 mg/dL and 13.92 ± 2.66 mg/dL, respectively (P < 0.001), and at day 14 after the treatment were 5.45 ± 2.59 mg/dL and 11.91 ± 2.83 mg/dL, respectively (P < 0.001). Furthermore, serum aspartate aminotransferase (AST) was detected <21 U/L in the ROC analysis after UDCA treatment (P = 0.04).

Conclusion

The study outcomes indicated that an efficient reduction in total bilirubin levels may be achieved, and outpatient clinic follow-up period may be reduced in patients whom UDCA was administrated. Moreover, it may be speculated that AST can be used to evaluate the efficacy after treatment. However, studies with larger sample sizes are needed for the routine use of UDCA in the treatment of prolonged jaundice.

Pharmacotherapies of NAFLD: updated opportunities based on metabolic intervention

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease that is becoming increasingly prevalent, and it ranges from simple steatosis to cirrhosis. However, there is still a lack of pharmacotherapeutic strategies approved by the Food and Drug Administration, which results in a higher risk of death related to carcinoma and cardiovascular complications. Of note, it is well established that the pathogenesis of NAFLD is tightly associated with whole metabolic dysfunction. Thus, targeting interconnected metabolic conditions could present promising benefits to NAFLD, according to a number of clinical studies. Here, we summarize the metabolic characteristics of the development of NAFLD, including glucose metabolism, lipid metabolism and intestinal metabolism, and provide insight into pharmacological targets. In addition, we present updates on the progresses in the development of pharmacotherapeutic strategies based on metabolic intervention globally, which could lead to new opportunities for NAFLD drug development.

The alteration of gut microbiota in venlafaxine-ameliorated chronic unpredictable mild stress-induced depression in mice

Depression is associated with intestinal dysbiosis. Venlafaxine is a commonly used antidepressant in clinical practice as a serotonin and noradrenaline reuptake inhibitor. However, its effects on gut bacteria in depression remain unclear. Here, we established a mouse model of depression induced by chronic unpredictable mild stress (CUMS), and investigated the alterations of venlafaxine on the gut microbiota and potential key bacteria. Our data show that venlafaxine exerts antidepressant effects by restoring the serotonin (5-HT) system and glutamate (Glu) levels in CUMS mice. Moreover, we revealed that venlafaxine altered the diversity of gut bacteria in CUMS mice, and at genus level, Blautia, Oscillibacter, Tyzzerella, Butyricicoccus, and Enterorhabdus are the key bacteria responsible for venlafaxine-ameliorated depression in mice. Among these potential key bacteria, Blautia, Oscillibacter, and Butyricicoccus are correlated significantly with the 5-HT and 5-hydroxyindoleacetic acid levels; while Tyzzerella is correlated markedly with Glu levels. We further show that venlafaxine affected multiple functional metabolic pathways of gut bacteria in mice with CUMS-induced depression. Our results suggest that venlafaxine possibly ameliorates depression via modulating gut bacteria, and found the potential targets of its antidepressant effects.

Ursodeoxycholic Acid Use After Bariatric Surgery: Effects on Metabolic and Inflammatory Blood Markers

BACKGROUND

In addition to the reduction of symptomatic gallstone disease, ursodeoxycholic acid (UDCA) might also have beneficial metabolic effects after bariatric surgery. We examined the impact of UDCA on liver enzymes, hemoglobin A1c (HbA1c), lipids, and inflammation markers.

METHODS

Patients in the UPGRADE trial (placebo-controlled, double-blind) were randomized between UDCA 900 mg daily or placebo pills for 6 months after bariatric surgery. Patients without blood measurements pre- or 6 months postoperatively were excluded. The change in liver enzymes, Hba1c, lipids, and inflammation markers after surgery were compared between the UDCA and placebo group, followed by a postoperative cross-sectional comparison.

RESULTS

In total, 513 patients were included (age [mean ± SD] 45.6 ± 10.7 years; 79% female). Preoperative blood values did not differ between UDCA (n = 266) and placebo (n = 247) groups. Increase of alkaline phosphatase (ALP) was greater in the UDCA group (mean difference 3.81 U/l [95%CI 0.50 7.12]). Change in other liver enzymes, HbA1c, lipids, and CRP levels did not differ. Postoperative cross-sectional comparison in 316 adherent patients also revealed a higher total cholesterol (mean difference 0.25 mg/dl [95%CI 0.07-0.42]), lower aspartate aminotransferase (mean difference -3.12 U/l [-5.16 - -1.08]), and lower alanine aminotransferase level (mean difference -5.89 U/l [-9.41 - -2.37]) in the UDCA group.

CONCLUSION

UDCA treatment leads to a higher, but clinically irrelevant increase in ALP level in patients 6 months after bariatric surgery. No other changes in metabolic or inflammatory markers were observed. Except for the reduction of gallstone formation, UDCA has no effects after bariatric surgery.

A Dual Coverage Monitoring of the Bile Acids Profile in the Liver-Gut Axis throughout the Whole Inflammation-Cancer Transformation Progressive: Reveal Hepatocellular Carcinoma Pathogenesis

Hepatocellular carcinoma (HCC) is the terminal phase of multiple chronic liver diseases, and evidence supports chronic uncontrollable inflammation being one of the potential mechanisms leading to HCC formation. The dysregulation of bile acid homeostasis in the enterohepatic circulation has become a hot research issue concerning revealing the pathogenesis of the inflammatory-cancerous transformation process. We reproduced the development of HCC through an N-nitrosodiethylamine (DEN)-induced rat model in 20 weeks. We achieved the monitoring of the bile acid profile in the plasma, liver, and intestine during the evolution of "hepatitis-cirrhosis-HCC" by using an ultra-performance liquid chromatography-tandem mass spectrometer for absolute quantification of bile acids. We observed differences in the level of primary and secondary bile acids both in plasma, liver, and intestine when compared to controls, particularly a sustained reduction of intestine taurine-conjugated bile acid level. Moreover, we identified chenodeoxycholic acid, lithocholic acid, ursodeoxycholic acid, and glycolithocholic acid in plasma as biomarkers for early diagnosis of HCC. We also identified bile acid-CoA:amino acid N-acyltransferase (BAAT) by gene set enrichment analysis, which dominates the final step in the synthesis of conjugated bile acids associated with the inflammatory-cancer transformation process. In conclusion, our study provided comprehensive bile acid metabolic fingerprinting in the liver-gut axis during the inflammation-cancer transformation process, laying the foundation for providing a new perspective for the diagnosis, prevention, and treatment of HCC.

Diagnosis by Microbial Culture, Breath Tests and Urinary Excretion Tests, and Treatments of Small Intestinal Bacterial Overgrowth

Small intestinal bacterial overgrowth (SIBO) is characterized as the increase in the number and/or alteration in the type of bacteria in the upper gastrointestinal tract and accompanies various bowel symptoms such as abdominal pain, bloating, gases, diarrhea, and so on. Clinically, SIBO is diagnosed by microbial culture in duodenum/jejunum fluid aspirates and/or the breath tests (BT) of hydrogen/methane gases after ingestion of carbohydrates such as glucose. The cultural analysis of aspirates is regarded as the golden standard for the diagnosis of SIBO; however, this is invasive and is not without risk to the patients. BT is an inexpensive and safe diagnostic test but lacks diagnostic sensitivity and specificity depending on the disease states of patients. Additionally, the urinary excretion tests are used for the SIBO diagnosis using chemically synthesized bile acid conjugates such as cholic acid (CA) conjugated with para-aminobenzoic acid (PABA-CA), ursodeoxycholic acid (UDCA) conjugated with PABA (PABA-UDCA) or conjugated with 5-aminosalicylic acid (5-ASA-UDCA). These conjugates are split by bacterial bile acid (cholylglycine) hydrolase. In the tests, the time courses of the urinary excretion rates of PABA or 5-ASA, including their metabolites, are determined as the measure of hydrolytic activity of intestinal bacteria. Although the number of clinical trials with this urinary excretion tests is small, results demonstrated the usefulness of bile acid conjugates as SIBO diagnostic substrates. PABA-UDCA disulfate, a single-pass type unabsorbable compound without the hydrolysis of conjugates, was likely to offer a simple and rapid method for the evaluation of SIBO without the use of radioisotopes or expensive special apparatus. Treatments of SIBO with antibiotics, probiotics, therapeutic diets, herbal medicines, and/or fecal microbiota transplantation are also reviewed.

Gut microbiota in dementia with Lewy bodies

Gut microbiota and fecal bile acids were analyzed in 278 patients with α-synucleinopathies, which were comprised of 28 patients with dementia with Lewy bodies (DLB), 224 patients with Parkinson's disease (PD), and 26 patients with idiopathic rapid eye movement sleep behavior disorder (iRBD). Similarly to PD, short-chain fatty acids-producing genera were decreased in DLB. Additionally, Ruminococcus torques and Collinsella were increased in DLB, which were not changed in PD. Random forest models to differentiate DLB and PD showed that high Ruminococcus torques and high Collinsella, which presumably increase intestinal permeability, as well as low Bifidobacterium, which are also observed in Alzheimer's disease, were predictive of DLB. As Ruminococcus torques and Collinsella are also major secondary bile acids-producing bacteria, we quantified fecal bile acids and found that the production of ursodeoxycholic acid (UDCA) was high in DLB. Increased UDCA in DLB may mitigate neuroinflammation at the substantia nigra, whereas neuroinflammation may not be critical at the neocortex. Theraeutic intervention to increase Bifidobacteirum and its metabolites may retard the development and progression of DLB.

Effects of oral tauroursodeoxycholic acid and/or intestinal probiotics on serum biochemical indexes and bile composition in patients with cholecystolithiasis

Background: In recent years, gallstones have become a major condition affecting people’s health. Cholecystectomy remains an effective treatment method, but it has large risk factors. It is well known that the hepatoenteric axis plays a key role in gallstone formation, and it is gradually becoming a research focus. Cholesterol homeostasis can be regulated by the liver and intestinal tract in our bodies, and intestinal flora can regulate the digestion and absorption of cholesterol. These two factors are closely related to the formation of gallstones.

Aim: To investigate the effects of tauroursodeoxycholic acid (TUDCA) and/or intestinal probiotics on serum biochemical indexes and bile composition in patients with cholecystolithiasis.

Methods: For this study, 96 patients with cholecystolithiasis were recruited at our hospital. The patients were randomly divided into four groups according to a random number table: group Ⅰ (TUDCA, 24 cases), group Ⅱ (intestinal probiotics, 24 cases), group Ⅲ (TUDCA and intestinal probiotics, 24 cases) and group Ⅳ (control group, 24 cases). All patients underwent laparoscopic gallbladder-preserving lithotomy or laparoscopic cholecystectomy. Bile samples were identified and extracted during the operation.

Results: The results revealed that the levels of serum total bile acid (TBA), serum total cholesterol (TCHOL) and serum triglyceride in groups I, II and III before and after the intervention were statistically significant (p < 0.05). There were significant differences in serum low-density lipoprotein cholesterol (LDL-C) between groups I and II before and after the intervention (p < 0.05), but the serum LDL-C level in group Ⅲ before and after the intervention was similar (p > 0.05). Regarding bile, TBA levels demonstrated no significant difference between groups I and III (p > 0.05), and the differences between the other two groups were statistically significant (p < 0.05). No significant difference was identified in phospholipid and TCHOL levels between groups I and Ⅲ (p > 0.05), and the differences between the other two groups were statistically significant (p < 0.05). There were significant differences in the levels of free Ca²⁺, pH value and glycoprotein in bile among the four groups (p < 0.05). The levels of cholic acid, chenodeoxycholic acid and deoxycholic acid in bile were significantly different among the four groups (p < 0.05). The level of lithocholic acid (LCA) in groups Ⅱ and Ⅲ was similar, as was the level of LCA in groups I and ⅠV, but the difference in level between the other two groups was statistically significant (p < 0.05).

Conclusion: The combination of TUDCA and intestinal probiotics did not enhance the effect of either treatment. The use of intestinal probiotics alone can maximise the reverse development of bile composition in patients with cholecystolithiasis compared with TUDCA alone and a combination of TUDCA and intestinal probiotics, thereby reducing gallstone formation.

Role of ursodeoxycholic acid in neonatal indirect hyperbilirubinemia: a systematic review and meta-analysis of randomized controlled trials

Background

Neonatal jaundice is a transitional phenomenon affecting three out of five full-term newborns globally. Ursodeoxycholic acid could be beneficial in neonatal jaundice needing phototherapy. 

Methods

We searched PubMed, EBSCO, ProQuest, and Cochrane Library up to August 21^st, 2021, for articles to be reviewed. Meta-analysis using random-effects model was performed.

Results

Eight studies involving 1116 neonates were chosen in this review; however, only five studies were included for meta-analysis. Phototherapy duration was significantly lower in the interventional group with high heterogeneities. Subgroup analysis of the phototherapy duration based on the risk of bias resulted in a shorter duration (mean difference (MD) = –17.82; 95% CI = –20.17 to –15.47; p =  < 0.001) with low heterogeneity in the treatment group. Secondary outcome focusing on mean total serum bilirubin showed a lower mean total serum bilirubin in 48 h post-treatment (MD = –0.43; 95% CI = –0.64 to –0.22; p =  < 0.0001) with low heterogeneities in Asian countries.”

Conclusions

Ursodeoxycholic acid might be considered as a novel adjuvant therapy in neonatal indirect hyperbilirubinemia to shorten the phototherapy duration and lower the mean total serum bilirubin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13052-022-01372-w.

Melatonin relieves hepatic lipid dysmetabolism caused by aging via modifying the secondary bile acid pattern of gut microbes

It has been reported that aging-generated gut microecosystem may promote host hepatic lipid dysmetabolism through shaping the pattern of secondary bile acids (BAs). Then as an oral drug, melatonin (Mel)-mediated beneficial efforts on the communication between gut microbiota and aging host are still not clearly. Here, we show that aging significantly shapes the pattern of gut microbiota and BAs, whereas Mel treatment reverses these phenotypes (P < 0.05), which is identified to depend on the existence of gut microbiota. Mechanistically, aging-triggered high-level expression of ileac farnesoid X receptor (FXR) is significantly decreased through Mel-mediated inhibition on Campylobacter jejuni (C. jejuni)-induced deconjugation of tauroursodeoxycholic acid (TUDCA) and glycoursodeoxycholic acid (GUDCA) (P < 0.05). The aging-induced high-level of serum taurine chenodeoxycholic acid (TCDCA) activate trimethylamine-N-oxide (TMAO)-triggered activating transcriptional factor 4 (ATF4) signaling via hepatic FXR, which further regulates hepatic BAs metabolism, whereas TUDCA inhibits aging-triggered high-level of hepatic ATF4. Overall, Mel reduces C. jejuni-mediated deconjugation of TUDCA to inhibit aging-triggered high-level expression of hepatic FXR, which further decreases hepatic TMAO production, to relieve hepatic lipid dysmetabolism.

Bile Reflux Gastritis: Insights into Pathogenesis, Relevant Factors, Carcinomatous Risk, Diagnosis, and Management

Bile reflux gastritis (BRG), a kind of gastrointestinal disorder in clinical practice, is characterized by regurgitation and inflammation. However, lack of guidelines leads to simple cognition and even ignorance of this disease for clinicians. Primarily, making the pathogenesis of BRG clear contributes to a correct and general understanding of this disease for physicians. Next, although recently there has been an increasing awareness among researchers in terms of the relevant factors for BRG, further studies involving large samples are still required to certify the relationship between them explicitly. Besides, researches have established that BRG is closely associated with the development of precancerous lesions and gastric cancer. Till now, there is still no golden standard for diagnosis of BRG. Nevertheless, advances in techniques, especially extensive applications of endoscopy and chemical analysis of reflux contents, have improved our ability to identify the occurrence of this disease as well as distinguishing physiological reflux from pathological reflux. Finally, it is fortunate for patients that more and more importance has been attached to the treatment of BRG. From lifestyle modification to drug therapy to surgery, all of them with the view of realizing symptomatic relief are employed for patients with BRG. In this review, we briefly evaluate this disorder based on the best available evidence, offering an overview of its complicated pathogenesis, diverse relevant factors, potential carcinomatous risk, modern diagnostic investigations, and effective therapeutic plans.

Rapid identification of bear bile powder from other bile sources using chip-based nano-electrospray ionization tandem mass spectrometry

RATIONALE

Bear bile powder (BBP) is a widely used traditional Chinese medicine (TCM), and bile acids (BAs) are the main active components in BBP. Due to the scarcity of BBP resources, adulterations often occur in the market. Conventional methods to distinguish them are usually complicated and time-consuming. To enhance effectiveness and accuracy, a rapid and rough analytical method is desperately needed.

METHODS

In this study, a rapid strategy using chip-based nano-electrospray ionization tandem mass spectrometry (nano-ESI-MS/MS) was established to distinguish BBP from other sources of bile powder (BP). In addition, the results were further verified by ultra-high-performance liquid chromatography combined with high-resolution mass spectrometry (UPLC/MS).

RESULTS

The precision of the chip-based nano-ESI-MS/MS method was validated to be acceptable with relative standard deviation (RSD) <15%. The distinction between BBP and other sources of BP, including common adulterants of pig bile powder (PBP), cattle bile powder (CBP), sheep bile powder (SBP), and chicken bile powder (CkBP), can be observed in the spectra. By using orthogonal partial least-squares discriminant analysis (OPLS-DA), more potential m/z markers were investigated. A BAs-related m/z marker of 498.3 was discovered as a typical differential molecular ion peak and was identified as tauroursodeoxycholic acid (TUDCA) and taurochenodeoxycholic acid (TCDCA) in BBP.

CONCLUSIONS

The proposed strategy has simple sample pretreatment steps and significantly shortened analysis time. As an emerging technology, chip-based nano-ESI-MS not only provides a reference for the rapid distinction of adulterated Chinese medicines, but also provides some insights into the identification of other chemicals and foods.

Roles of ursodeoxycholic acid in the bile biochemistry and metabolomics in patients with choledocholithiasis: a prospective study

INTRODUCTION

Recurrence after the endoscopic treatment of common bile duct stones (CBDS) is related to bile metabolism and bile compositions. Ursodeoxycholic acid (UDCA) has been proved effective in reducing the recurrence of CBDS. However, the detailed effects of UDCA on bile metabolism are still not extensively explored.

OBJECTIVES

This study aimed to analyze the role of UDCA in patients with choledocholithiasis (CDC) from the perspective of biochemistry and metabolomics.

METHODS

A total of 89 patients with CDC who underwent endoscopic retrograde cholangiopancreatography were prospectively examined and randomly assigned to control and UDCA groups. The biochemical detections (cholesterol, bilirubin, and so on) were performed on the collected bile. Moreover, the metabolomics analysis was conducted based on bile from 20 patients in the UDCA group.

RESULTS

The bile levels of cholesterol and endotoxins significantly decreased after UDCA treatment. Regarding bile metabolomics, the levels of 25 metabolites changed significantly after UDCA treatment. The pathway enrichment analysis showed that the UDCA addition evoked a common response related to phenylalanine, tyrosine, and tryptophan biosynthesis; phenylalanine metabolism; arachidonic acid metabolism; and terpenoid backbone biosynthesis.

CONCLUSIONS

UDCA treatment within a short time interval (7 days) did not improve the circulating laboratory values in patients with CDC who had undergone endoscopy surgery. However, relevant decreases in the bile levels of cholesterol and endotoxin were observed. UDCA evoked a common response related to lipid metabolism and amino acid metabolism, which probably reduced the bile level of cholesterol, protected hepatocytes, and corrected the abnormality of lipid metabolism caused by CDC.

A molecular mechanism of UDCA engagement with GPBAR and subsequent G protein interaction revealed by scattered alanine scanning

As the most known therapeutic component of bear bile acids, ursodeoxycholic acid (UDCA) is an FDA-approved drug for the treatment of primary biliary cirrhosis (PBC), the dissolution of cholesterol gallstones. UDCA produces many beneficial effects on metabolism and immune responses via its interaction with the membrane G protein-coupled bile acid receptor (GPBAR); however, how UDCA interacts with GPBAR and its selective cellular effects remain elusive. In this study, we delineated the interaction of UDCA with GPBAR and activation mechanism of GPBAR by scattered alanine scanning and molecular docking. Our results indicated that transmembrane helix 2 (TM2), TM3, TM5 and TM6 of GPBAR contribute to the interaction of UDCA in GPBAR binding pocket. Moreover, we predicted that the engagement of the 3-OH of UDCA with phenolic oxygen of Y240^6.51 in GPBAR plays a key role in GPBAR activation. Unexpectedly, in addition to the well-known roles of intracellular loop2 (ICL2) residues, we identified that ICL3 residues play an important role in G protein coupling to GPBAR in response to UDCA binding. Our study provides a preliminary molecular mechanism of how GPBAR recognizes UDCA and subsequent activation and G protein interaction, which may facilitate the development of new bile acid derivatives as therapeutics.

Ursodeoxycholic acid prevention on cholestasis associated with total parenteral nutrition in preterm infants: a randomized trial

BACKGROUND

Preterm infants with long-term parenteral nutrition (PN) therapy are at risk for cholestasis associated with total parenteral nutrition (PNAC). This study examined the safety and efficacy of ursodeoxycholic acid (UDCA) in preventing PNAC in preterm infants. Our research aimed to investigate the prophylactic effect of preventive oral UDCA on PNAC in preterm infants.

METHODS

We compared oral administration of UDCA prophylaxis with no prophylaxis in a randomized, open-label, proof-of-concept trial in preterm neonates with PN therapy. The low-birth-weight preterm infants (< 1800 g) who were registered to the neonatal intensive care unit (NICU) within 24 hours after birth were randomized. The main endpoint was the weekly values of direct bilirubin (DB) of neonates during the NICU stay.

RESULTS

Eventually, a total of 102 preterm neonates from January 2021 to July 2021 were enrolled in this prospective study (42 in the UDCA group and 60 in the control group). Notably, the peak serum level of DB [13.0 (12-16) vs. 15.2 (12.5-19.6) μmol/L, P < 0.05)] was significantly lower in the UDCA group than that in the control group without prevention. The peak serum level of total bilirubin (101.1 ± 34 vs. 116.5 ± 28.7 μmol/L, P < 0.05) was also significantly lower in the UDCA group than in the control group. Furthermore, the proportion of patients who suffered from neonatal cholestasis (0.0% vs. 11.7%, P < 0.05) in the UDCA group was significantly lower.

CONCLUSION

UDCA prophylaxis is beneficial in preventing PNAC in NICU infants receiving prolonged PN.

Targeting gut microbial bile salt hydrolase (BSH) by diet supplements: new insights into dietary modulation of human health

Dietary supplements could modulate the abundance of BSH-producing bacteria to regulate the BSH enzyme activity, thereby change the BAs composition to regulate FXR signaling, which then regulate human health.

The Role of Bile Acids in Cardiovascular Diseases: from Mechanisms to Clinical Implications

Bile acids (BAs), key regulators in the metabolic network, are not only involved in lipid digestion and absorption but also serve as potential therapeutic targets for metabolic disorders. Studies have shown that cardiac dysfunction is associated with abnormal BA metabolic pathways. As ligands for several nuclear receptors and membrane receptors, BAs systematically regulate the homeostasis of metabolism and participate in cardiovascular diseases (CVDs), such as myocardial infarction, diabetic cardiomyopathy, atherosclerosis, arrhythmia, and heart failure. However, the molecular mechanism by which BAs trigger CVDs remains controversial. Therefore, the regulation of BA signal transduction by modulating the synthesis and composition of BAs is an interesting and novel direction for potential therapies for CVDs. Here, we mainly summarized the metabolism of BAs and their role in cardiomyocytes and noncardiomyocytes in CVDs. Moreover, we comprehensively discussed the clinical prospects of BAs in CVDs and analyzed the clinical diagnostic and application value of BAs. The latest development prospects of BAs in the field of new drug development are also prospected. We aimed to elucidate the underlying mechanism of BAs treatment in CVDs, and the relationship between BAs and CVDs may provide new avenues for the prevention and treatment of these diseases.

Bile acids as regulatory molecules and potential targets in metabolic diseases

Bile acids are important hydroxylated steroids that are synthesized in the liver from cholesterol for intestinal absorption of lipids and other fatty-nutrient. They also display remarkable and immense functions such as regulating immune responses, managing the apoptosis of cells, participating in glucose metabolism, and so on. Some bile acids were used for the treatment or prevention of diseases such as gallstones, primary biliary cirrhosis, and colorectal cancer. Meanwhile, the accumulation of toxic bile acids leads to apoptosis, necrosis, and inflammation. Alteration of bile acids metabolism, as well as the gut microbiota that interacted with bile acids, contributes to the pathogenesis of metabolic diseases. Therefore, the purpose of this review is to summarize the current functions and pre-clinical or clinical applications of bile acids, and to further discuss the alteration of bile acids in metabolic disorders as well as the manipulation of bile acids metabolism as potential therapeutic targets.

Current understanding of autophagy in intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is the most common liver disease during pregnancy. Manifested with pruritus and elevation in bile acids, the etiology of ICP is still poorly understood. Although ICP is considered relatively benign for the mother, increased rates of adverse fetal outcomes including sudden fetal demise are possible devastating outcomes associated with ICP. Limited understanding of the underlying mechanisms restricted treatment options and managements of ICP. In recent decades, evolving evidence indicated the significance of autophagy in pregnancy and pregnancy complications. Autophagy is an ancient self-defense mechanism which is essential for cell survival, differentiation and development. Autophagy has pivotal roles in embryogenesis, implantation, and maintenance of pregnancy, and is involved in the orchestration of diverse physiological and pathological cellular responses in patients with pregnancy complications. Recent advances in these research fields provide tantalizing targets on autophagy to improve the care of pregnant women. This review summarizes recent advances in understanding autophagy in ICP and its possible roles in the causation and prevention of ICP.

Ursodeoxycholic acid suppresses the malignant progression of colorectal cancer through TGR5-YAP axis

The Hippo/YAP pathway plays an important role in the development of cancers. Previous studies have reported that bile acids can activate YAP (Yes Associated Protein) to promote tumorigenesis and tumor progression. Ursodeoxycholic acid (UDCA) is a long-established old drug used for cholestasis treatment. So far, the effect of UDCA on YAP signaling in colorectal cancer (CRC) is not well defined. This study means to explore relationship of UDCA and YAP in CRC. UDCA suppressed YAP signaling by activating the membrane G-protein-coupled bile acid receptor (TGR5). TGR5 mainly regulated cAMP/PKA signaling pathway to inhibit RhoA activity, thereby suppressing YAP signaling. Moreover, the restoration of YAP expression alleviated the inhibitory effect of UDCA on CRC cell proliferation. In AOM/DSS-induced CRC model, UDCA inhibited tumor growth in a concentration-dependent manner and decreased expression of YAP and Ki67. UDCA plays a distinguished role in regulating YAP signaling and CRC growth from the primary bile acids and partial secondary bile acids, demonstrating the importance of maintaining normal intestinal bile acid metabolism in cancer patients. It also presents a potential therapeutic intervention for CRC.

Modulation of the Gut Microbiota-farnesoid X Receptor Axis Improves Deoxycholic Acid-induced Intestinal Inflammation in Mice

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) is associated with gut dysbiosis and dysregulation of bile acid metabolism. A high luminal content of deoxycholic acid (DCA) with consumption of a Westernised diet is implicated in the pathogenesis of IBD. The aim of the study is to explore the role of intestinal microbiota and bile acid metabolism in mice with DCA-induced intestinal inflammation.

METHODS

Wild-type C57BL mice, 4 weeks old, were fed with AIN-93G (control diet), AIN-93G+0.2% DCA, AIN-93G+0.2% DCA+6 weeks of fexaramine (FXR agonist), or AIN-93G+0.2% DCA+antibiotic cocktail, for 24 weeks. Histopathology, western blotting, and qPCR were performed on the intestinal tissue. Faecal microbiota was analysed by 16S rDNA sequencing. Faecal bile acid and short chain fatty acid (SCFA) levels were analysed by chromatography.

RESULTS

Gut dysbiosis and enlarged bile acid pool were observed in DCA-treated mice, accompanied by a lower farnesoid X receptor (FXR) activity in the intestine. Administration of fexaramine mitigated DCA-induced intestinal injury, restored intestinal FXR activity, activated fibroblast growth factor 15, and normalised bile acid metabolism. Furthermore, fexaramine administration increased the abundance of SCFA-producing bacteria. Depletion of the commensal microbiota with antibiotics decreased the diversity of the intestinal microbiota, attenuated bile acid synthesis, and reduced intestinal inflammation induced by DCA.

CONCLUSIONS

DCA induced-intestinal inflammation is associated with alterations of gut microbiota and bile acid profiles. Interventions targeting the gut microbiota-FXR signalling pathway may reduce DCA-induced intestinal disease.

Hyocholic acid species improve glucose homeostasis through a distinct TGR5 and FXR signaling mechanism

Hyocholic acid (HCA) and its derivatives are found in trace amounts in human blood but constitute approximately 76% of the bile acid (BA) pool in pigs, a species known for its exceptional resistance to type 2 diabetes. Here, we show that BA depletion in pigs suppressed secretion of glucagon-like peptide-1 (GLP-1) and increased blood glucose levels. HCA administration in diabetic mouse models improved serum fasting GLP-1 secretion and glucose homeostasis to a greater extent than tauroursodeoxycholic acid. HCA upregulated GLP-1 production and secretion in enteroendocrine cells via simultaneously activating G-protein-coupled BA receptor, TGR5, and inhibiting farnesoid X receptor (FXR), a unique mechanism that is not found in other BA species. We verified the findings in TGR5 knockout, intestinal FXR activation, and GLP-1 receptor inhibition mouse models. Finally, we confirmed in a clinical cohort, that lower serum concentrations of HCA species were associated with diabetes and closely related to glycemic markers.

Non-alcoholic fatty liver disease in adults: clinic, diagnostics, treatment. Guidelines for therapists, third version

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Hyocholic acid species as novel biomarkers for metabolic disorders

Hyocholic acid (HCA) is a major bile acid (BA) species in the BA pool of pigs, a species known for its exceptional resistance to spontaneous development of diabetic phenotypes. HCA and its derivatives are also present in human blood and urine. We investigate whether human HCA profiles can predict the development of metabolic disorders. We find in the first cohort (n = 1107) that both obesity and diabetes are associated with lower serum concentrations of HCA species. A separate cohort study (n = 91) validates this finding and further reveals that individuals with pre-diabetes are associated with lower levels of HCA species in feces. Serum HCA levels increase in the patients after gastric bypass surgery (n = 38) and can predict the remission of diabetes two years after surgery. The results are replicated in two independent, prospective cohorts (n = 132 and n = 207), where serum HCA species are found to be strong predictors for metabolic disorders in 5 and 10 years, respectively. These findings underscore the association of HCA species with diabetes, and demonstrate the feasibility of using HCA profiles to assess the future risk of developing metabolic abnormalities.

Bile acids and their receptors in metabolic disorders

Bile acids are a large family of atypical steroids which exert their functions by binding to a family of ubiquitous cell membrane and nuclear receptors. There are two main bile acid activated receptors, FXR and GPBAR1, that are exclusively activated by bile acids, while other receptors CAR, LXRs, PXR, RORγT, S1PR2and VDR are activated by bile acids in addition to other more selective endogenous ligands. In the intestine, activation of FXR and GPBAR1 promotes the release of FGF15/19 and GLP1 which integrate their signaling with direct effects exerted by theother receptors in target tissues. This network is tuned in a time ordered manner by circadian rhythm and is critical for the regulation of metabolic process including autophagy, fast-to-feed transition, lipid and glucose metabolism, energy balance and immune responses. In the last decade FXR ligands have entered clinical trials but development of systemic FXR agonists has been proven challenging because their side effects including increased levels of cholesterol and Low Density Lipoproteins cholesterol (LDL-c) and reduced High-Density Lipoprotein cholesterol (HDL-c). In addition, pruritus has emerged as a common, dose related, side effect of FXR ligands. Intestinal-restricted FXR and GPBAR1 agonists and dual FXR/GPBAR1 agonists have been developed. Here we review the last decade in bile acids physiology and pharmacology.

The Liver under the Spotlight: Bile Acids and Oxysterols as Pivotal Actors Controlling Metabolism

Among the myriad of molecules produced by the liver, both bile acids and their precursors, the oxysterols are becoming pivotal bioactive lipids which have been underestimated for a long time. Their actions are ranging from regulation of energy homeostasis (i.e., glucose and lipid metabolism) to inflammation and immunity, thereby opening the avenue to new treatments to tackle metabolic disorders associated with obesity (e.g., type 2 diabetes and hepatic steatosis) and inflammatory diseases. Here, we review the biosynthesis of these endocrine factors including their interconnection with the gut microbiota and their impact on host homeostasis as well as their attractive potential for the development of therapeutic strategies for metabolic disorders.

Targeting the alternative bile acid synthetic pathway for metabolic diseases

The gut microbiota is profoundly involved in glucose and lipid metabolism, in part by regulating bile acid (BA) metabolism and affecting multiple BA-receptor signaling pathways. BAs are synthesized in the liver by multi-step reactions catalyzed via two distinct routes, the classical pathway (producing the 12α-hydroxylated primary BA, cholic acid), and the alternative pathway (producing the non-12α-hydroxylated primary BA, chenodeoxycholic acid). BA synthesis and excretion is a major pathway of cholesterol and lipid catabolism, and thus, is implicated in a variety of metabolic diseases including obesity, insulin resistance, and nonalcoholic fatty liver disease. Additionally, both oxysterols and BAs function as signaling molecules that activate multiple nuclear and membrane receptor-mediated signaling pathways in various tissues, regulating glucose, lipid homeostasis, inflammation, and energy expenditure. Modulating BA synthesis and composition to regulate BA signaling is an interesting and novel direction for developing therapies for metabolic disease. In this review, we summarize the most recent findings on the role of BA synthetic pathways, with a focus on the role of the alternative pathway, which has been under-investigated, in treating hyperglycemia and fatty liver disease. We also discuss future perspectives to develop promising pharmacological strategies targeting the alternative BA synthetic pathway for the treatment of metabolic diseases.

Bile acid profiles in bile and feces of obese mice by a high-performance liquid chromatography-tandem mass spectrometry

Bile acids (BAs) play a pivotal role in manipulating the development of metabolic diseases. However, due to the compositional complexity and functional variation of BAs, it remains unclear about the changes in BA pool for individuals with obesity or metabolic syndrome. We established a high-performance liquid chromatography-mass spectrometer detection system for the simultaneous analysis of both unconjugated and conjugated BAs in the bile and feces of mice. Ten BAs were completely separated, identified, and quantified with low limit of detection (0.5 ng/mL) and inter/intraday precision (relative standard deviation < 12%). By using this method, these BAs in bile and feces of mice were quantified. The result showed that taurochenodeoxycholic acid, taurine-conjugated α-muricholic acids, and taurine-conjugated β-muricholic acids were the dominated BAs in bile, whereas deoxycholic acid and chenodeoxycholic acid predominated in feces. Further, most of the BA levels were significantly elevated in either bile or fecal samples of high-fat diet-fed mice as compared with those in normal chow diet-fed mice, indicating that excessive production of BAs was closely associated with the occurrence of lipid metabolism disorders. In summary, the present method is practicable for analysis of BAs in bile and fecal samples of patients with obesity.

Changes in plasma bile acids are associated with gallbladder stones and polyps

BACKGROUND

The development of gallbladder disease (GBD) is related to bile acid (BA) metabolism, and the rate of BA circulation increases the risk of biliary cancer. However, it is unclear whether patterns of circulating bile acids (BAs) change in patients with benign GBDs such as gallbladder stones and polyps. Herein, we compared and characterised plasma BA profiles in patients with cholecystolithiasis and non-neoplastic polyps with healthy controls, and explored relationships between plasma BA profiles, demographics, and laboratory test indices.

METHODS

A total of 330 subjects (13 healthy controls, 292 cholecystolithiasis and 25 non-neoplastic polyps) were recruited and plasma BA profiles including 14 metabolites from patients with pathologically confirmed cholecystolithiasis and non-neoplastic polyps were compared with controls. BAs were quantitated by liquid chromatography and mass spectrometry, and statistical and regression analyses of demographics and laboratory test indices were performed.

RESULTS

Females displayed a higher burden of GBD than males (63.36% cholecystolithiasis, 60% non-neoplastic polyps). Cholecystolithiasis and non-neoplastic polyps were associated with increased plasma total secondary BAs, while levels of primary BAs were lower than in healthy controls. Plasma ursodeoxycholic acid (UDCA), tauroursodeoxycholic acid (TUDCA), glycyurdeoxycholic acid (GUDCA), taurochenodeoxycholic acid (TCDCA) and glycochenodeoxycholic acid (GCDCA) were decreased significantly in GBDs, and ursodeoxycholic acid (UDCA) was negatively correlated with white blood cell count and neutrophil percentage.

CONCLUSIONS

Secondary BA levels were higher in patients with cholecystolithiasis and non-neoplastic polyps. White blood cell count and percentage of neutrophil in peripheral blood were negatively correlated with UDCA, indicating an anti-inflammation effect of UDCA.

Serum Cholesterol-Lowering Activity of β-Sitosterol Laurate Is Attributed to the Reduction of Both Cholesterol Absorption and Bile Acids Reabsorption in Hamsters

The research was performed to delineate how β-sitosterol laurate (β-SLE) consumption influenced serum and hepatic lipids. The results showed that 220 mg/5 mL oil/kg body weight of β-SLE robustly reduced serum total triglyceride and cholesterol levels and the epididymal adipocyte size, and efficiently protected hepatic polyunsaturated fatty acids against lipid peroxidation through superoxide dismutase and glutathione transferase activity enhancement and malondialdehyde level reduction. Based on the changes of fecal cholesterol contents, fecal and hepatic bile acid (BAs) levels, and related protein expression, it was concluded that the mechanisms for lowering serum cholesterol by β-SLE involved (i) the enhanced excretion of fecal cholesterol via down-regulation of intestinal Niemann-Pick C1-like 1 protein; (ii) the increased conversion from cholesterol to primary BAs via up-regulation of cholesterol-7α-hydroxylase and sterol 27-hydroxylase, which was induced by the reduced BAs reabsorption through up-regulating ileal apical sodium-dependent bile acid transporter and ileal bile acid-binding protein.

The effect of ursodeoxycholic acid on the relative expression of the lipid metabolism genes in mouse cholesterol gallstone models

BACKGROUND

Many studies indicate that gallstone formation has genetic components. The abnormal expression of lipid-related genes could be the basis for particular forms of cholesterol gallstone disease. The aim of this study was to obtain insight into lipid metabolism disorder during cholesterol gallstone formation and to evaluate the effect of ursodeoxycholic acid (UDCA) on the improvement of bile lithogenicity and its potential influence on the transcription of lipid-related genes.

METHODS

Gallstone-susceptible mouse models were induced by feeding with a lithogenic diet (LD) for 8 weeks. Bile and liver tissues were obtained from these mouse models after 0, 4 and 8 weeks. Bile lipids were measured enzymatically, and the cholesterol saturation index (CSI) was calculated to evaluate the bile lithogenicity by using Carey's critical tables. Real-time polymerase chain reaction (RT-PCR) was used to detect the mRNA expression levels of farnesoid X receptor (FXR), liver X receptor (LXR), adenosine triphosphate-binding cassette subfamily G member 5/8 (ABCG5/8), cholesterol 7-α hydroxylase (CYP7A1), oxysterol 7-α hydroxylase (CYP7B1), sterol 27-α hydroxylase (CYP27A1), peroxisome proliferator-activated receptor alpha (PPAR-α) and adenosine triphosphate-binding cassette subfamily B member 11 (ABCB11).

RESULTS

The rate of gallstone formation was 100% in the 4-week group but only 30% in the UDCA-treated group. The UDCA-treated group had a significantly lower CSI compared with other groups. Of special note, the data on the effects of UDCA showed higher expression levels of ABCG8, ABCB11 and CYP27A1, as well as lower expression levels of LXR and PPAR-α, compared to the model control group.

CONCLUSIONS

UDCA exhibits tremendously potent activity in restraining lipid accumulation, thus reversing the lithogenic effect and protecting hepatocytes from serious pathological damage. The abnormal expression of ABCG8, CYP7A1, CYP27A1, LXR and PPAR-α might lead to high lithogenicity of bile. These results are helpful in exploring new lipid metabolism pathways and potential targets for the treatment of cholesterol stones and for providing some basis for the study of the pathogenesis and genetic characteristics of cholelithiasis. Research on the mechanism of UDCA in improving lipid metabolism and bile lithogenicity may be helpful for clinical treatment and for reducing the incidence of gallstones.

Yinchenzhufu decoction protects against alpha-naphthylisothiocyanate-induced acute cholestatic liver injury in mice by ameliorating disordered bile acid homeostasis and inhibiting inflammatory responses

ETHNOPHARMACOLOGICAL RELEVANCE

Intrahepatic cholestasis is a common condition of many liver diseases with few therapies. Yinchenzhufu decoction (YCZFD) is a representative traditional Chinese herbal formula used for treating jaundice and liver disease.

AIM OF THE STUDY

To investigate the hepatoprotective effect of YCZFD against cholestatic liver injury and reveal its potential mechanism.

MATERIALS AND METHODS

Mice with alpha-naphthyl isothiocyanate (ANIT)-induced intrahepatic cholestasis were orally administered YCZFD at doses of 3, 6, and 12g crude drug/kg for 2 weeks followed by subsequent analyses. A serum metabolomics study was then performed to explore the different metabolites influenced by YCZFD using ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap hybrid mass spectrometry (UPLC-LTQ-Orbitrap-MS/MS).The levels of individual bile acids in the serum, liver, and bile were determined by UPLC-MS/MS. The expression of metabolic enzymes, transporters, inflammatory factors, and cytokeratin-19 (CK-19) was determined by real-time PCR, western blotting, and immunohistochemistry.

RESULTS

YCZFD administration decreased the serum biochemical indexes and ameliorated pathological damage, such as hepatic necrosis and inflammatory cell infiltration. Serum metabolomics revealed that the metabolites influenced by YCZFD were mainly associated with bile acid metabolism and inflammation. YCZFD administration effectively ameliorated the disordered bile acid homeostasis. The bile acid transporter, multidrug-resistance associated protein 2 (Mrp2), and the metabolic enzyme, cytochrome P450 2b10 (Cyp2b10), were upregulated in the YCZFD intervention group compared to those in the ANIT-induced group. YCZFD administration also significantly inhibited nuclear factor-κB (NF-κB) and its phosphorylation and decreased the expression of proinflammatory cytokines including tumor necrosis factor-α, interleukin-1β, and intercellular adhesion molecule-1 in ANIT-induced cholestatic mice. Additionally, the level of CK-19 was lower in the YCZFD intervention group than in the ANIT-induced cholestatic mice.

CONCLUSION

YCZFD administration ameliorated disordered bile acid homeostasis, inhibited NF-κB pathway-mediated inflammation, and protected the liver from bile duct injury. Therefore, YCZFD exerted a protective effect against cholestatic liver injury.

Ursodeoxycholic acid protects against cisplatin-induced acute kidney injury and mitochondrial dysfunction through acting on ALDH1L2

Mitochondrial dysfunction plays an important role in acute kidney injury (AKI). Thus, the agents improving the mitochondrial function could be beneficial for treating AKI. Ursodeoxycholic acid (UDCA) has been demonstrated to prevent mitochondrial dysfunction under pathology, however, its role in AKI and the underlying mechanism remain unknown. This study aimed to evaluate the effect of UDCA on cisplatin-induced AKI. In vivo, C57BL/6 J mice were treated with cisplatin (25 mg/kg) for 72 h to induce AKI through a single intraperitoneal (i.p.) injection with or without UDCA (60 mg/kg/day) administration by gavage. Renal function, mitochondrial function and oxidative stress were analyzed to evaluate kidney injury. In vitro, mouse proximal tubular cells (mPTCs) and human proximal tubule epithelial cells (HK2) were treated with cisplatin with or without UDCA treatment for 24 h. Transcriptomic RNA-seq was preformed to analyze possible targets of UDCA. Our results showed that cisplatin-induced increments of serum creatinine (Scr), blood urea nitrogen (BUN), and cystatin C were significantly reduced by UDCA along with ameliorated renal tubular injury evidenced by improved renal histology and blocked upregulation of neutrophil gelatinase associated lipocalin (NGAL) and kidney injury molecule 1 (KIM-1). Meanwhile, the apoptosis induced by cisplatin was also markedly attenuated by UDCA administration. In vitro, UDCA treatment protected against tubular cell apoptosis possibly through antagonizing mitochondrial dysfunction and oxidative stress by targeting ALDH1L2 which was screened out by an RNA-seq analysis. Knockout of ALDH1L2 by CRISPR/Cas9 greatly blunted the protective effects of UDCA in renal tubular cells. Moreover, UDCA did not diminish cisplatin's antineoplastic effect in human cancer cells. In all, our results demonstrated that UDCA protects against cisplatin-induced AKI through improving mitochondrial function through acting on the expression of ALDH1L2, suggesting a clinical potential of UDCA for the treatment of AKI.