Bile Acid Levels Research Articles

Long-term effects of Nε-carboxymethyllysine intake on intestinal barrier permeability: Associations with gut microbiota and bile acids.

Advanced glycation end products (AGEs) in processed foods are closely linked to intestinal injury. However, the long-term effects of exposure to free Nɛ-carboxymethyl lysine (CML), a prevalent AGE molecule, on intestinal barrier integrity have been rarely evaluated. This study investigated the temporal effects of CML exposure on intestinal barrier permeability in C57BL/6N mice at diet-related doses over 12, 14, and 16weeks. No significant changes were observed at 12weeks, but CML exposure significantly increased intestinal permeability at 14 and 16weeks, accompanied by elevated serum LPS levels, colonic histological damage, and reduced tight junction protein expression at 16weeks. CML exposure also altered gut microbiota composition and intestinal bile acid (BA) profiles, specifically reducing TDCA, GDCA, and GCDCA levels. Given the important role of colonic BA receptor signaling in maintaining the intestinal barrier integrity, the impact of CML on BA receptor signaling was assessed. CML exposure significantly downregulated BA receptor TGR5-YAP signaling in mice, while no significant effects were observed in vitro, suggesting that the changes observed in TGR5-YAP signaling in vivo may not result from the direct effects of CML. Spearman's correlation analysis revealed strong associations between altered gut microbiota, BA levels, TGR5-YAP signaling, and intestinal barrier injury. This study highlighted the chronic health risks of long-term CML intake and provided new insights into the links between CML-induced intestinal toxicity, gut microbiota, BA profiles, and BA receptor signaling.

Analysis of gut and mucosal microbiomes in patients with extrahepatic cholangiocarcinoma.

620 Background: Cholangiocarcinoma is an aggressive malignancy with a poor prognosis. While gut microbial dysbiosis is linked to various diseases, including biliary disorders and cancer, its association with cholangiocarcinoma remains unclear. Methods: This study compared the mucosal and gut microbiomes of patients with extrahepatic cholangiocarcinoma (n = 21) to those with cholecystitis (n = 21) and healthy individuals (n = 28). Mucosal microbiomes were collected from cancer lesions and gallbladders, with fecal samples obtained from 31 participants. The 16S rRNA gene (V3 and V4 region) was sequenced using the Illumina MiSeq platform and analyzed with QIIME 2. Results: 16S rRNA sequencing revealed Proteobacteria as the dominant taxon in the cancer cohort, with Klebsiella, Aeromonas, Staphylococcus, Fusobacterium, and Haemophilus also enriched. In contrast, Firmicutes dominated in the cholecystitis and control cohorts. β-diversity analysis highlighted significant differences between cohorts. Elevated levels of bile acids, particularly chenodeoxycholic acid and ursodeoxycholic acid, were observed in the cancer cohort and positively correlated with Proteobacteria, Aeromonas, Enterobacter, and Enterococcus. Conclusions: These findings suggest that microbiome dysbiosis contributes to cholangiocarcinoma development.

DOP123 Linking microbial genes to mucosal metabolites uncovers host-microbial interactions during 5-ASA therapy for ulcerative colitis

Abstract Background The severity of ulcerative colitis (UC) depends on the state of the colon mucosa, where achieving mucosal remission markedly improves patient prognosis and quality of life. The study aimed to characterize essential mucosal metabolites and microbial gene involved in UC remission, and to elucidate the mechanisms by which specific metabolites regulate intestinal homeostasis. Methods An integrated metagenomic and metabolomic analysis was conducted to elucidate the correlation between disease-associated microbes and host mucosal metabolites. Participants included non-UC controls and individuals with UC, comprising the responding group (UCR) and ineffective group (UCA) in 5-ASA treatment. The differential metabolite was further investigated using a DSS-induced colitis mouse model, followed by in vitro experiments to explore the mechanisms. Results The levels of mucosal secondary bile acids were found to have a significant negative association with intestinal inflammation during 5-ASA treatment. Integrated analysis of metagenomics and metabolomics revealed that host mucosal bile acid metabolites were negatively associated with the bile acid synthesis-related genes cbh in microbial genomes. Administration of the secondary bile acid mitigated mucosal inflammation in a colitis model by decreasing the proportion of Th17 and pathogenic Th17 cells. This secondary bile acid functions as an immunomodulatory metabolite, suppressing glycolysis in Th17-polarizing T cells to inhibit the Th17 cell response and modulating the gut microbiota. Conclusion These findings suggest that alterations in microbiome-metabolome interactions are critical for maintaining mucosal homeostasis during UC remission. The specific bile acid acts as an immunomodulatory metabolite, and may represent a potential therapeutic strategy for UC.

P0596 Fecal bile acids predict the therapeutic effect of biological agents in patients with ulcerative colitis

Abstract Background Ulcerative colitis (UC) is a chronic non-specific inflammatory disease of the colon. Infliximab or vedolizumab is recommended for treatment of moderate to severe UC, but has a primary or secondary non-response rate. Receiving early predictions on treatment efficacy can offer substantial support for patients’ therapeutic interventions. We aim to use fecal bile acids to identify predictive biomarkers. Methods Fecal samples were collected from 55 UC patients hospitalized in the Second Hospital of Hebei Medical University and 10 healthy volunteers. UC patients were divided into clinical response group and clinical non-response group according to the therapeutic effect of biologics. Quantitative detection of target bile acids was performed on fecal samples. The bile acid levels of the two groups were compared, and the bile acids that predicted the therapeutic effect were screened by orthogonal partial least squares discriminant analysis (OPLS-DA) and the analysis of receiver working characteristic curve. Results Compared with healthy adults, patients with UC showed decreased total fecal bile acids, increased primary bile acids, and decreased secondary bile acids. After treatment with biologics, there was a decrease in primary bile acids and an increase in secondary bile acids. In comparison between clinical responders and non-responders, fecal lithocholic acid and deoxycholic acid were significantly increased, and the ratio of primary bile acids to secondary bile acids was significantly decreased. When deoxycholic acid was higher than 29.55 ug/g or lithocholic acid was higher than 0.195 ug/g, it had predictive value for clinical response. Conclusion Fecal bile acids, especially deoxycholic acid and lithocholic acid, may serve as novel biomarkers for predicting the therapeutic effect of biological agents in UC patients.

Oral vancomycin treatment alters levels of indole derivatives and secondary bile acids modulating the expression of mTOR pathway genes in astrocytes during EAE.

Astrocytes play important roles in the central nervous system (CNS) during health and disease. Prior studies have shown that gut commensals derived indole derivatives as well as secondary bile acids modulate astrocyte function during the late stage of EAE (recovery phase). Here we show that administering vancomycin to mice starting during the early stage of EAE improved disease recovery, an effect that is mediated by the gut microbiota. We observed that 6 taxa within the Clostridia vadin BB60 group were enriched in vancomycin treated mice compared to untreated EAE mice. Vancomycin-treated EAE mice also had elevated serum levels of the anti-inflammatory tryptophan derived metabolite, indole-3-lactic acid and decreased levels of deoxycholic acid, a pro-inflammatory secondary bile acid. RNA sequencing revealed altered expression of several genes belonging to the mammalian target of rapamycin (mTOR) pathway in astrocytes obtained during the late stage of EAE from vancomycin treated EAE mice. Furthermore, we observed a link between serum levels of indole derivatives and bile acids and expression of several genes belonging to the mTOR pathway. Interestingly, the mTOR signaling cascades have been implicated in several key biological processes including innate (e.g., astrocyte) immune responses as well as neuronal toxicity/degeneration. In addition, rapamycin, a specific inhibitor of mTOR, has been shown to inhibit the induction and progression of established EAE. Collectively, our findings suggest that the neuroprotective effect of vancomycin is at least partially mediated by indole derivatives and secondary bile acids modulating the expression of mTOR pathway genes in astrocytes.

The role of the Systemic Inflammatory Response Index (SIRI) and other maternal biochemical markers in determining the severity of intrahepatic cholestasis of pregnancy.

To investigate the roles of the systemic inflammatory response index (SIRI) and other biochemical markers obtained from maternal blood in determining the diagnosis and severity of pregnancy cholestasis. In this retrospective case-control study, a total of 815 pregnant women including 546 healthy pregnant women [serum total bile acid (TBA) level < 10 μmol/L, control group], 185 patients with mild cholestasis [serum TBA level < 40 μmol/L, mild intrahepatic cholestasis of pregnancy (ICP) group] and 84 patients with severe cholestasis (serum TBA level ≥ 40 μmol/L, severe ICP group) were evaluated. The groups were compared regarding demographic data, clinical characteristics, SIRI (neutrophilcount*monocytecount/lymphocyte count), and other laboratory data. Cut-off values that could predict ICP were calculated. The average neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), and systemic inflammatory response index (SIRI) were found to be statistically significantly higher in the severe ICP group compared with the control group and mild ICP group (p < 0.01 and p < 0.05). The best SIRI cut-off value was 2.3302 (60.3% sensitivity and 52.2% specificity) [area under the curve: 0.590 ± 0.023, 95% confidence interval (CI): 0.546-0.634; p < 0.001]. SIRI may be a useful marker in determining the diagnosis and severity of ICP. However, were commend that studies be conducted in larger groups and indifferent trimesters.

Whole-exome sequencing identifies novel mutation in intrahepatic cholestasis of pregnancy: A case report and literature review.

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease characterized by pruritus and elevated total bile acid (TBA) levels. The most serious impact of ICP is sudden unexplained intrauterine fetal death, especially when an associated TBA ≥ 100 µmol/L is confirmed.We report a case of a 27-year-old female patient with early-onset severe refractory ICP. Whole-exome sequencing and mutation analyses were performed to obtain genetic data on the patient and her mother. Sanger sequencing was performed to screen the mutation site. Computer-based algorithms were applied to predict the pathogenesis of the identified mutation. Subsequently, we conducted a literature review to characterize the pathological features and perinatal management of severe refractory ICP, especially ICP with genetic susceptibility.A heterozygous mutation in the ABCD3 gene: c.130C > T/p.Pro44Ser was detected in this patient. Through the analysis of pathogenicity prediction software, the mutations were disease-causing. This is the first report to identify the novel p.Pro44Ser mutations of ABCD3 gene in ICP patients.Our report provides new insights into the genetic architecture of ICP involving ABCD3 variants. Early-onset severe refractory ICP is rare and mutations in bile acid metabolism genes might accentuate the phenotype. Emphasized perinatal management and screening for potential pathogenicity sites of variants that drive specific recognition of ICP is necessary.

High leafy and root vegetables and high rice dietary patterns were associated with primary and secondary bile acid levels in the feces

Colorectal cancer has the second highest mortality among cancer sites worldwide, with increasing morbidity, high recurrence rates, and even poorer postoperative quality of life. Therefore, preventive strategies for colorectal cancer should be established. This study aimed to cross-sectionally explore dietary patterns affecting the intestinal metabolism of bile acids (BAs), a risk factor for colorectal cancer, in young Japanese women. We collected fecal samples for intestinal microbiota and BA analysis. We used the Bristol scale to determine 1-week defecation status. Moreover, the brief-type self-administered diet history questionnaire was used for habitual dietary intake status. Reduced-rank regression analysis revealed dietary patterns related to fecal BA levels. The relationship between dietary patterns and fecal BA levels was adjusted for defecation status and intestinal microbiota variables using analysis of covariance. Reduced-rank regression analysis generated two dietary pattern scores related to fecal BA levels. First, the score was associated with a greater intake of leafy and root vegetables, and higher values were associated with greater fecal cholic and chenodeoxycholic acid levels and lower deoxycholic and lithocholic acid levels. Second, the score was associated with greater rice intake and lower Western sweets, pork, beef, and egg intake, and higher values were associated with lower deoxycholic and lithocholic acid levels. These relationships remained after adjusting for intestinal microbiota and defecation status variables.

Comparative Analysis of γ-Cyclodextrin, Perilla Oil, and Their Inclusion Complexes on Liver Injury and Dyslipidemia Associated with Elevated Gastrointestinal 12-Hydroxylated Bile Acid Levels.

Our previous study demonstrated that γ-cyclodextrin (γ-CD)-perilla oil inclusion complexes increase plasma α-linolenic acid and eicosapentaenoic acid levels in healthy rats without adverse effects. The present study examined the effects of perilla oil, γ-CD, and their inclusion complexes on rats fed cholic acid (CA) to mimic the elevated gastrointestinal 12-hydroxylated (12OH) bile acid levels in high-fat diet-fed rats. Rats fed CA (CA group) tended to have higher AST, ALT, plasma total cholesterol (T-CHO), and triglyceride (TG) levels compared to controls fed a standard diet without CA. Rats fed CA and perilla oil (CA+LP group) showed a tendency for lower AST and plasma TG levels than those in the CA group. Rats fed CA and γ-CD (CA+CD group) had significantly higher AST, ALT, plasma T-CHO, and TG levels than the controls, indicating severe liver injury and dyslipidemia. Rats fed CA and the γ-CD-perilla oil inclusion complex (CA+IC group) had significantly lower AST and ALT levels than the CA+CD rats, with a trend towards lower plasma T-CHO and TG levels. Plasma α-linolenic acid and eicosapentaenoic acid levels were significantly higher in the CA+LP and CA+IC groups than in the controls and CA+CD groups. However, the CA+IC group tended to have lower α-linolenic acid levels and significantly lower eicosapentaenoic acid levels than the CA+LP group. This suggests an accelerated conversion of α-linolenic acid to eicosapentaenoic acid in the CA+IC group, which may contribute to the attenuation of liver injury and dyslipidemia. These findings suggest that γ-CD may exacerbate liver injury and dyslipidemia caused by elevated gastrointestinal 12OH bile acid levels, whereas γ-CD-perilla oil inclusion complexes may ameliorate these effects by altering fatty acid metabolism. Furthermore, we recommend evaluating γ-CD safety in both healthy and pathological models and carefully selecting compounds co-ingested with γ-CD.

Sequential Versus Continuous Feeding and Its Effect on the Gut Microbiota in Critically Ill Patients: A Randomized Controlled Trial.

Gut microbiota disturbance may worsen critical illnesses and is responsible for the progression of multiple organ dysfunction syndrome. In our previous study, there was a trend towards a higher α-diversity of the gut microbiota in sequential feeding (SF) than in continuous feeding (CF) for critically ill patients. We designed this non-blinded, randomized controlled study to confirm these results. All the enrolled patients received continuous feeding in the beginning. After achieving ≥80% of the nutrition target calories (25-30 kcal/kg/d), the patients were randomized into the SF group or the CF group. In the SF group, continuous feeding was changed into intermittent feeding. The total daily dosage of enteral nutrition was equally distributed during three periods at 7-9:00, 11-13:00 and 17-19:00. After 7 days of randomization, fresh stool and serum were collected for 16S rRNA gene sequencing and untargeted metabolomics analysis respectively. Meanwhile, routine blood test indicators and metabolic indicators were recorded. Finally, data from 65 patients in the SF group and 69 patients in the CF group were used for intention-to-treat analysis. There was no difference in the Shannon index between the SF group and CF group [2.5 (1.7-3.4) vs. 2.6 (1.5-3.5), P =0.934]. However, at the genus level, the abundances of Erysipelotrichaceae_UCG-003 and Howardella increased in the SF group. Some metabolic indicators (the albumin level, total cholesterol level and total bile acid level) and the increases in lymphocyte counts in the SF group were different from those in the CF group (P <0.05). In untargeted metabolomic analysis, 58 differentially abundant metabolites between the two groups were found. The pathway with the highest enrichment factors was primary bile acid biosynthesis according to the Kyoto Encyclopedia of Genes and Genomes Database classification. Regarding adverse events, the gut tolerance, average glucose and incidence of hyperglycemia and hypoglycemia were similar between the SF group and CF group. The mortality rate in the SF group was lower than that in the CF group, but there was no statistical difference (9.2% vs. 13.0%, P=0.484). SF did not increase the diversity of gut microbiota in critically ill patients. However, it did alter the abundances of some gut microbes and affect some metabolites. Its clinical significance requires further exploration. In addition, the gut tolerance and safety of SF were similar to that of CF. www. gov, registration number NCT04443335. Registered 21 June, 2020.

Host metabolism balances microbial regulation of bile acid signalling.

Metabolites derived from the intestinal microbiota, including bile acids (BA), extensively modulate vertebrate physiology, including development1, metabolism2-4, immune responses5-7 and cognitive function8. However, to what extent host responses balance the physiological effects of microbiota-derived metabolites remains unclear9,10. Here, using untargeted metabolomics of mouse tissues, we identified a family of BA-methylcysteamine (BA-MCY) conjugates that are abundant in the intestine and dependent on vanin 1 (VNN1), a pantetheinase highly expressed in intestinal tissues. This host-dependent MCY conjugation inverts BA function in the hepatobiliary system. Whereas microbiota-derived free BAs function as agonists of the farnesoid X receptor (FXR) and negatively regulate BA production, BA-MCYs act as potent antagonists of FXR and promote expression of BA biosynthesis genes in vivo. Supplementation with stable-isotope-labelled BA-MCY increased BA production in an FXR-dependent manner, and BA-MCY supplementation in a mouse model of hypercholesteraemia decreased lipid accumulation in the liver, consistent with BA-MCYs acting as intestinal FXR antagonists. The levels of BA-MCY were reduced in microbiota-deficient mice and restored by transplantation of human faecal microbiota. Dietary intervention with inulin fibre further increased levels of both free BAs and BA-MCY levels, indicating that BA-MCY production by the host is regulated by levels of microbiota-derived free BAs. We further show that diverse BA-MCYs are also present in human serum. Together, our results indicate that BA-MCY conjugation by the host balances host-dependent and microbiota-dependent metabolic pathways that regulate FXR-dependent physiology.

Real-world effectiveness and safety of bulevirtide monotherapy for up to 96 weeks in patients with HDV-related cirrhosis.

Bulevirtide (BLV) 2 mg/day is EMA approved for treatment of compensated chronic hepatitis due to Delta virus (HDV) infection, however real-life data in large cohorts of patients with cirrhosis are lacking. Consecutive HDV-infected patients with cirrhosis starting BLV 2 mg/day since September 2019 were included in a European retrospective multicenter real-life study (SAVE-D). Patient characteristics before and during BLV treatment were collected. Virological, biochemical, combined responses, adverse events and liver-related events (HCC, decompensation, liver transplant) were assessed. 244 patients with HDV-related cirrhosis receiving BLV monotherapy for a median of 92 (IQR 71-96) weeks were included: at BLV start, median (IQR) age was 49 (40-58) years, 61% men, ALT 80 (55-130) U/L, liver stiffness measurement (LSM) 18.3 (13.0-26.3) kPa, platelets 94 (67-145) x 103/mm3, 54% with esophageal varices, 95% Child Pugh score A, 10% HIV-coinfected, 92% on NUC, median HDV RNA 5.4 (4.1-6.5) Log10 IU/mL, HBsAg 3.8 (3.4-4.1) Log10 IU/mL. At weeks (W)48 and 96, virological, biochemical and combined responses were observed in 65% and 79%, 61% and 64%, 44% and 54% of patients, respectively. AST, GGT, albumin, IgG and LSM values significantly improved throughout treatment. Serum bile acid levels increased in most patients, only 10% patients reported mild and transient pruritus, independently of bile acid levels. The W96 cumulative risk of de-novo HCC and decompensation was 3.0% (95% CI 2-6%) and 2.8% (95% CI 1-5%), respectively. Thirteen (5%) patients underwent liver transplantation (n=11 for HCC, n=2 for decompensation). BLV 2 mg/day monotherapy up to 96 weeks was safe and effective in patients with HDV-related cirrhosis. Virological and clinical responses increased over time. Liver-related complications were few.

Goose Deoxycholic Acid Ameliorates Liver Injury in Laying Hens with Fatty Liver Hemorrhage Syndrome by Inhibiting the Inflammatory Response

Fatty liver hemorrhagic syndrome (FLHS) in laying hens is a nutritional and metabolic disease involving liver enlargement, hepatic steatosis, and hepatic hemorrhage as the primary symptoms. The syndrome is prone to occur during the peak laying period of laying hens, which has resulted in significant economic losses in the laying hen breeding industry; however, the specific pathogenesis of FLHS remains unclear. Our group and previous studies have shown that bile acid levels are significantly decreased during the development of fatty liver and that targeted activation of bile acid–related signaling pathways is beneficial for preventing and treating fatty liver. In this study, we generated a FLHS laying hen model by feeding hens a high-energy, low-protein diet, with goose deoxycholic acid (CDCA) given as an intervention. HE staining, fluorescence quantitative PCR, and ELISA were used to evaluate the effects of CDCA on pathological changes and inflammatory responses in the liver. The results showed that hepatic hemorrhage in FLHS laying hens was reduced after CDCA treatment. Furthermore, fat vacuoles and transaminase levels decreased significantly. In addition, expression levels of M1-type macrophage markers and polarization products were significantly reduced, and the expression of pro-inflammatory regulatory factors related to the JAK-STAT signaling pathway, LPS-TLR4-Myd88–NF-kB signaling pathway, and NLRP3 inflammasomes decreased significantly as well. Expression levels of M2-type macrophage markers and polarization products increased significantly, as did the expression of anti-inflammatory regulators related to the JAK-STAT signaling pathway. These results suggest that CDCA ameliorates liver injury in laying hens with FLHS by inhibiting macrophage M1-type polarization and the resulting pro-inflammatory response, thereby promoting M2-type macrophage polarization and an anti-inflammatory response.

Probiotic interventions with highly acid-tolerant Levilactobacillus brevis strains improve lipid metabolism and gut microbial balance in obese mice.

Many studies have shown that specific lactic acid bacteria (LAB) strains can delay obesity, offering a viable alternative to medications and surgeries. However, the mining and development of highly effective LAB strains for obesity control is still limited. In this study, the naturally highly acid-tolerant and gamma-aminobutyric acid-producing Levilactobacillus brevis D17 and its glnR deletion strain were used to investigate their anti-obesity effects. In an 8-week mouse experiment, L. brevis D17 and its glnR-deletion strain D17ΔglnR significantly reduced weight gain by 28.4% and 29.1%, respectively, improving abnormal serum indicators and glucose metabolism caused by a high-fat diet. Furthermore, L. brevis D17 and its glnR-deletion strain D17ΔglnR successfully colonized in the gut. Both D17 and D17ΔglnR interventions significantly restored the relative abundance of Muribaculaceae, Ileibacterium valens, Lactobacillus, Faecalibaculum, Bifidobacterium globosum, Akkermansia muciniphila, and Romboutsia ilealis, whereas they significantly reduced potentially harmful bacteria like Leptogranulimonas, Flintibacter, and Alistipes. Additionally, L. brevis intervention effectively decreased the levels of primary bile acids and increased secondary bile acids in the gut, thus balancing bile acid metabolism. The transcriptional analysis suggested that D17 and D17ΔglnR interventions may activate the AMPK signaling pathway in the liver to inhibit lipogenesis, activate the cAMP pathway to promote lipolysis, and inhibit pro-inflammatory macrophage infiltration to block inflammatory responses. These results indicate that L. brevis D17 and its glnR-deletion mutant strain D17ΔglnR show great potential in combating obesity. Moreover, these results also provide insights into the underlying mechanism behind their anti-obesity properties.

Mechanistic implications of the Mediterranean diet in patients with newly diagnosed Crohn's disease- multi-omic results from a prospective cohort.

To decipher the mechanisms underlying the protective role of the Mediterranean diet (MED) in Crohn's disease (CD), we explored the implications of adherence to MED on CD course, inflammatory markers, microbial and metabolite composition. Patients with newly diagnosed CD were recruited and followed prospectively. MED adherence was assessed by repeated food frequency questionnaires (FFQ), using a predefined IBDMED score, alongside validated MED adherence screeners. Crohn's disease activity index (CDAI), C-reactive protein (CRP), fecal calprotectin and microbial composition (16S-rRNA-sequencing) were assessed each visit. Baseline serum and fecal samples were analyzed for targeted quantitative metabolomics. Consecutive patients: 271 (52% males, average age- 31±12 years, B1 phenotype- 75%). FFQ collected: 636 (range 1-5 FFQ per patient). Adherence to MED was associated with a non-complicated CD course, and inversely correlated with CDAI, fecal calprotectin, CRP and microbial dysbiosis index (all P < .05). Increasing adherence to MED over time correlated with reduced CDAI and inflammatory markers (P < .05). Adherence to MED correlated with a microbial cluster of commensals and short-chain fatty acid producers including Faecalibacterium, and with plant metabolites, vitamin derivatives and amino acids. Conversely, adherence to MED inversely correlated with a cluster of oral genera, Escherichia coli and Ruminococcus gnavus, known CD-associated species, and with tryptophan metabolites, ceramides and primary bile acids (FDR < .2). Adherence to MED is associated with beneficial clinical outcomes and decreased inflammatory markers. These may be driven by lower levels of primary bile-acids and microbial dysbiosis and a beneficial microbial and metabolite composition. Randomized controlled trials are needed to evaluate the role of MED in CD management.

L-Carnitine Improves Muscle Nutrient Metabolism and Intestinal Health in High-Fat-Fed Carp (Cyprinus carpio).

L-Carnitine is widely recognized for its involvement in lipid metabolism, but its effects on muscle quality and gut health in carp have not been well studied. The research aimed to investigate how L-carnitine influences muscle quality and intestinal health in high-fat-fed carp. The study was separated into four groups that received either the standard diet, a high-fat diet (HFD), or a HFD supplemented with 500 mg/kg L-carnitine (LLC), or a HFD supplemented with 1000 mg/kg L-carnitine (HLC) for 56 days. L-Carnitine was found to significantly reduce blood lipid levels. In addition, L-carnitine increased the crude protein content and decreased the crude fat content of high-fat-fed carp muscle while improving muscle fiber morphology and muscle quality. L-Carnitine increased the expression of genes related to intestinal tight junction proteins (claudin-2, occludin, and zo-1), improved the expression of genes related to intestinal inflammation, and enhanced the physical barrier function and organization of the intestine. Analysis of intestinal flora and intestinal metabolites showed that L-carnitine increased the diversity of the intestinal flora, increased the abundance of Cetobacterium, and influenced intestinal levels of bile acids, arachidonic acid, and tryptophan-related metabolites. In conclusion, supplementation with 1000 mg/kg L-carnitine improved muscle quality and intestinal health significantly in high-fat-fed carp by regulating muscle nutrient metabolism and intestinal flora.

Alpha-1 Antitrypsin Inclusions Sequester GRP78 in a Bile Acid-Inducible Manner.

The homozygous PiZ mutation (PIZZ genotype) constitutes the predominant cause of severe alpha-1 antitrypsin (AAT) deficiency and leads to liver disease via hepatocellular AAT aggregation. We systematically analysed the composition of AAT aggregates and studied the impact of bile acids. AAT inclusions were isolated from livers of PiZ overexpressing mice and PIZZ humans via fluorescence-activated and immunomagnetic sorting (FACS/MACS), while insoluble proteins were obtained via Triton-X extraction. Inclusion composition was evaluated through mass-spectrometry (MS), immunoblotting and immunostaining. Hepatocytes with versus without AAT aggregates were obtained via microdissection. Serum bile acids were assessed in 57 PIZZ subjects and 19 controls. Mice were administered 2% cholic acid (CA)-supplemented chow for 7 days. MS identified the key endoplasmic reticulum chaperone 78 kDa glucose-regulated protein (GRP78) in FACS/MACS pulldowns. GRP78 was also enriched in insoluble fractions from PiZ mice versus wild types and detected in insoluble fractions/MACS isolates from PIZZ liver explants. In cultured cells/primary hepatocytes, PiZ overexpression was associated with increased GRP78 mRNA/protein levels. In human livers, hepatocytes with AAT aggregates had higher GRP78 levels than hepatocytes without. PIZZ subjects displayed higher serum bile acid levels than controls and the highest levels were seen in individuals with liver injury/fibrosis. In PiZ mice, CA-mediated bile acid challenge resulted in increased liver injury and translocation of GRP78 into the aggregates. Our results demonstrate that GRP78 is sequestered within AAT inclusions. Bile acid accumulation, as seen in PIZZ subjects with liver disease, may promote GRP78 segregation and thereby augment liver damage. NCT02929940.

Targeted Plasma Bile Acid Metabolomic Analysis in Metabolic Dysfunction-Associated Steatohepatitis and Alcoholic Hepatitis.

Background: Even though many metabolic liver diseases can now be diagnosed using blood tests and diagnostic imaging, early diagnosis remains difficult. Understanding mechanisms contributing to the progression from Metabolic Dysfunction-Associated Steatohepatitis (MASH) and Alcoholic Hepatitis (AH) to cirrhosis is critical to reduce the burden of end-stage liver disease. Monitoring individual bile acids has been proposed as a way to distinguish various liver disorders. Methods: This study explored bile acid profiles in patients with MASH and AH. Plasma samples from patients with MASH, AH, and a control group were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify bile acid concentrations. Targeted metabolomic analysis was performed to compare bile acid levels between the hepatitis and control groups. Results: Concentrations of ursodeoxycholic acid (UDCA), chenodeoxycholic acid (CDCA), taurocholic acid (TCA), tauroursodeoxycholic acid (TUDCA), taurochenodeoxycholic acid (TCDCA), glycoursodeoxycholic acid (GUDCA), glycochenodeoxycholic acid (GCDCA), and glycocholic acid (GCA) were significantly elevated in the hepatitis group. Correlation analysis revealed strong positive relationships between the total and direct bilirubin levels and TUDCA and GCDCA. Aspartate aminotransferase (AST) showed strong positive correlations with TCDCA and GCDCA. Child-Pugh score, Fibrosis-4 index, and non-alcoholic fatty liver disease fibrosis score were positively correlated with GCA, whereas the aspartate aminotransferase-to-platelet ratio correlated with TCA, TCDCA, and GCA. The model for end-stage liver disease (MELD) score showed a strong positive correlation with GCDCA. Implications: GCDCA may serve as a predictive biomarker for liver damage, potentially enabling early diagnosis and targeted intervention in patients with MASH and AH.

Application of physiologically based (PBK) modeling to quantify the effect of the antibiotic tobramycin on bile acid levels in human plasma.

Systemic bile acid homeostasis plays an important role in human health. In this study, a physiologically based kinetic (PBK) model that includes microbial bile acid deconjugation and intestinal bile acid reuptake via the apical sodium-dependent bile acid transporter (ASBT) was applied to predict the systemic plasma bile acid concentrations in human upon oral treatment with the antibiotic tobramycin. Tobramycin was previously shown to inhibit intestinal deconjugation and reuptake of bile acids and to affect bile acid homeostasis upon oral exposure of rats. Kinetic parameters to define the effects of tobramycin on intestinal bile acid transport were determined in vitro using a Caco-2 cell layer Transwell model for studying the intestinal translocation of 4 model bile acids including glycochenodeoxycholic acid (GCDCA), glycocholic acid (GCA), glycodeoxycholic acid (GDCA), and deoxycholic acid (DCA), the latter as a model for unconjugated bile acids (uBA). Kinetic constants for the effect of tobramycin on intestinal microbial deconjugation were taken from previous in vitro studies using anaerobic fecal incubations. The PBK model simulations predicted that exposure to tobramycin at the dose level also used in the previous 28day rat study would reduce human plasma Cmax levels of GCA, GCDCA, GDCA, and DCA by 42.4%, 27.7%, 16.9%, and 75.8%. The reduction of conjugated bile acids is governed especially via an effect on ASBT-mediated intestinal uptake, and not via the effect of tobramycin on intestinal conjugation, likely because deconjugation happens to a large extent in the colon which has limited subsequent bile acid reuptake. The results reflect that oral exposure to xenobiotics that are not or poorly bioavailable can affect systemic bile acid homeostasis. Altogether, the PBK model appears to provide a 3R compliant tool to evaluate the effect of oral exposure to xenobiotics on host bile acid homeostasis via effects on intestinal bile acid deconjugation and reuptake.

Bile acids in follicular fluid: potential new therapeutic targets and predictive markers for women with diminished ovarian reserve

ObjectiveTo investigate the changes in bile acid (BA) metabolites within the follicular fluid (FF) of patients with diminished ovarian reserve (DOR) and to identify novel diagnostic markers that could facilitate early detection and intervention in DOR patients.DesignA total of 182 patients undergoing assisted reproductive technology (ART) were enrolled and categorized into the normal ovarian reserve (NOR) group (n = 91) or the DOR group (n = 91) to measure BA levels in FF. To identify the changes in granulosa cells (GCs), we collected GCs from an additional 7 groups of patients for transcriptome sequencing.SettingReproductive medicine center within a hospital and university research laboratory.PopulationA total of 182 patients undergoing assisted reproductive technology were enrolled and categorized into the NOR group (n = 91) or the DOR group (n = 91).MethodsIn this study, BA metabolites in FF of DOR and NOR patients were analyzed in detail by targeted metabolomics, and the correlation between BA levels in FF and clinical indicators was discussed. Then, we constructed a diagnostic model for DOR using the random forest algorithm based on five different BAs. Additionally, we performed a functional enrichment analysis on differentially expressed genes (DEGs) in GCs from both DOR and NOR patients.Main outcome measuresBA levels in FF and their correlation with clinical indicators; the areas under the curve (AUCs) of the random forest diagnostic model for DOR; and the DEGs and corresponding functional enrichment results of GC RNA analysis.Result (s)The levels of lithocholic acid, chenodeoxycholic acid, ursodeoxycholic acid, deoxycholic acid and cholic acid in FF of DOR group were lower than those of NOR group. And significant reductions in total, primary, secondary, and unconjugated BA levels were observed in the DOR group. The above five BAs levels were closely related to indicators of ovarian reserve. The AUC of the diagnostic model based on the above five BAs was 0.964. Based on transcriptome sequencing data from two groups of GCs, a total of 482 up-regulated and 654 down-regulated DEGs were identified. Gene ontology analysis revealed that the metabolic and biosynthetic processes of fatty acids, steroids, and cholesterol were enriched in these DEGs, whereas Kyoto Encyclopedia of Genes and Genomes analysis indicated enrichment of fatty acid and ovarian steroidogenesis.Conclusion(s)The levels of multiple BA metabolites in FF are significantly lower than those in patients with DOR and are closely related to the evaluation of ovarian reserve function.