Bile Acid Concentrations Research Articles

Effects of a 12-Week Whole-Grain or Refined Wheat Intervention on Plasma Acylcarnitines, Bile Acids, and Signaling Lipids and Association With Liver Fat

ObjectivesWhole-grain wheat consumption has been shown to have beneficial effects on liver health, including liver fat accumulation, as compared to refined wheat. The mechanisms underlying these effects remain unclear. In this study, we explored the effects of RW vs. WGW consumption on plasma levels of metabolites involved in lipid metabolism in order to identify potential underlying mechanisms of the preventive effect of WGW consumption on liver fat accumulation. MethodsWe performed a post-hoc analysis of a 12-week double-blind, randomized controlled trial in which 50 overweight or obese men and women aged 45–70 years with mildly elevated levels of plasma cholesterol were randomized to either 98 g/d of WGW or RW products. Before and after the intervention, fasting plasma concentrations of acylcarnitines, bile acids, and signaling lipids were measured by targeted UPLC MS/MS, intrahepatic triglycerides (IHTG) were quantified by 1H-MRS, and additional markers of liver health were assessed, including circulating levels of β-hydroxybutyrate, alanine transaminase, aspartate transaminase, γ-glutamyltransferase, serum amyloid A, and C-reactive protein. ResultsThe WGW intervention increased plasma concentrations of the two out of 52 signaling lipids platelet-activating factor (18:2) and lysophosphatidic acid (18:2), and decreased concentrations of lysophosphatidylglycerol (20:3), as compared to RW intervention, although these results were no longer statistically significant after FDR correction. Plasma concentrations of the 8 bile acids and 29 acylcarnitines that we measured were not affected differentially by the WGW or RW intervention. Changes in the above-mentioned metabolites were not correlated to change in IHTG upon the intervention. ConclusionsThe plasma acylcarnitines, bile acids, and signaling lipids that we measured do not seem to be directly involved in the mechanisms underlying the protective effect of WGW consumption or detrimental effect of RW consumption on liver fat accumulation. Funding SourcesFunding source: public-private partnership “Combining innovation with tradition: improving resilience with essential nutrients and whole wheat bread”, financed by Topsector Agri & Food (TKI-AF 12,083) and TNO roadmap Nutrition & Health. Co-funding: Cereal Partners Worldwide, the Dutch Bakery Center, and GoodMills Innovation GmbH.

Chitin-Glucan Supplementation Altered Gut Microbiota and Improved Postprandial Metabolism in Subjects at Cardiometabolic Risk

ObjectivesIn this exploratory study, we aimed at characterizing the impact of chitin-glucan (CG), an insoluble dietary fiber, on gut microbiota composition and functions as well as on the cardiometabolic profile in subjects at cardiometabolic risk. MethodsFifteen subjects were included in this double-blind, randomized, twice 3-week cross-over study and consumed 4.5g of CG or maltodextrin (control) as a supplement daily. Before and after the intervention phases, fasting and postprandial metabolic parameters and exhaled gases (hydrogen [H2] and methane [CH4]) were evaluated. Gut microbiota composition (16S next generation sequencing), fecal concentrations of bile acids, long- and short-chain fatty acids (LCFA, SCFA), zonulin, calprotectin and lipopolysaccharide binding protein (LBP) were analyzed. ResultsCompared to control, CG supplementation increased exhaled H2 following an enriched-fiber breakfast ingestion and decreased postprandial glycemia and triglyceridemia response to a standardized test meal challenge served at lunch. Of note, the decrease in postprandial glycemia was only observed in subjects with higher exhaled H2, assessed upon lactulose breath test performed at inclusion. CG decreased a family belonging to Actinobacteria phylum and increased 3 bacterial taxa: Erysipelotrichaceae UCG.003, Ruminococcaceae UCG.005 and Eubacterium ventriosum group. Fecal metabolites, inflammatory and intestinal permeability markers did not differ between groups. ConclusionsWe showed that CG supplementation modified the gut microbiota composition and improved postprandial glycemic response, an early determinant of cardiometabolic risk. Our results also suggest breath H2 production as a non-invasive parameter of interest for predicting the effectiveness of dietary fiber intervention. Funding SourcesThe FiberTAG project was initiated from a European Joint Programming Initiative “A Healthy Diet for a Healthy Life” (JPI HDHL). This study was supported by the Service Public de Wallonie. NMD is a recipient of a grant from Belgium National Scientific Research Fund and from UCLouvain. GGM is a recipient of a FSR grant from the UCLouvain.

Significance of the Vitamin D Receptor on Crosstalk with Nuclear Receptors and Regulation of Enzymes and Transporters.

The vitamin D receptor (VDR), in addition to other nuclear receptors, the pregnane X receptor (PXR) and constitutive androstane receptor (CAR), is involved in the regulation of enzymes, transporters and receptors, and therefore intimately affects drug disposition, tissue health, and the handling of endogenous and exogenous compounds. This review examines the role of 1α,25-dihydroxyvitamin D3 or calcitriol, the natural VDR ligand, on activation of the VDR and its crosstalk with other nuclear receptors towards the regulation of enzymes and transporters, notably many of the cytochrome P450s including CYP3A4 and sulfotransferase 2A1 (SULT2A1) as well as cholesterol 7α-hydroxylase (CYP7A1). Moreover, the VDR upregulates the intestinal channel, TRPV6, for calcium absorption, LDL receptor-related protein 1 (LRP1) and receptor for advanced glycation end products (RAGE) in brain for β-amyloid peptide efflux and influx, the sodium phosphate transporters (NaPi), theapical sodium-dependent bile acid transporter (ASBT) and organic solute transporters (OSTα-OSTβ) for bile acid absorption and efflux, respectively, the renal organic anion transporter 3 (OAT3) and several of the ATP-binding cassette protein transporters-the multidrug resistance protein 1 (MDR1) and the multidrug resistance-associated proteins (MRPs). Hence, the role of the VDR is increasingly being recognized for its therapeutic potential and pharmacologic activity, giving rise to drug-drug interactions (DDI). Therapeutically, ligand-activated VDR shows anti-inflammatory effects towards the suppression of inflammatory mediators, improves cognition by upregulating amyloid-beta (Aβ) peptide clearance in brain, and maintains phosphate, calcium, and parathyroid hormone (PTH) balance and kidney function and bone health, demonstrating the crucial roles of the VDR in disease progression and treatment of diseases.

Bile acids induce Ca2+ signaling and membrane permeabilizations in vagal nodose ganglion neurons

Bile acids (BAs) play an important role in the digestion of dietary fats and act as signaling molecules. However, due to their solubilizing properties, high concentrations in the gut may negatively affect gut epithelium and possibly afferent fibers innervating the gastrointestinal tract (GI). To determine the effect of BAs on intracellular Ca2+ and membrane permeabilization we tested a range of concentrations of two BAs on vagal nodose ganglion (NG) neurons, Chinese Hamster Ovary (CHO), and PC12 cell lines. NG explants from mice were drop-transduced with the genetically encoded Ca2+ indicator AAV9-Syn-jGCaMP7s and used to measure Ca2+ changes upon application of deoxycholic acid (DCA) and taurocholic acid (TCA). We found that both BAs induced a Ca2+ increase in NG neurons in a dose-dependent manner. The DCA-induced Ca2+ increase was dependent on intracellular Ca2+ stores. NG explants, with an intact peripheral part of the vagus nerve, showed excitation of NG neurons in nerve field recordings upon exposure to DCA. The viability of NG neurons at different BA concentrations was determined, and compared to CHO and PC12 cells lines using propidium iodide labeling, showing threshold concentrations of BA-induced cell death at 400–500 μM. These observations suggest that BAs act as Ca2+-inducing signaling molecules in vagal sensory neurons at low concentrations, but induce cell death at higher concentrations, which may occur during inflammatory bowel diseases.

Association of Serum and Fecal Bile Acid Patterns With Liver Fibrosis in Biopsy-Proven Nonalcoholic Fatty Liver Disease: An Observational Study.

No reports on both blood and fecal bile acids (BAs) in patients with nonalcoholic fatty liver disease (NAFLD) exist. We simultaneously assessed the serum and fecal BA patterns in healthy participants and those with NAFLD. We collected stool samples from 287 participants from 5 hospitals in Japan (healthy control [HC]: n = 88; mild fibrosis: n = 104; and advanced fibrosis group: n = 95). Blood samples were collected and analyzed for serum BAs and 7α-hydroxy-4-cholesten-3-one (C4)-a surrogate marker for BA synthesis ability-from 141 patients. Concentrations of BAs, including cholic acid (CA), deoxycholic acid (DCA), chenodeoxycholic acid, ursodeoxycholic acid, and lithocholic acid (LCA), were measured using liquid chromatography-mass spectrometry. The total fecal BA concentration was significantly higher in the NAFLD group with worsening of fibrosis than in the HC group. Most of the fecal BAs were secondary and unconjugated. In the fecal BA fraction, CA, DCA, chenodeoxycholic acid, ursodeoxycholic acid, and LCA were significantly higher in the NAFLD than in the HC group. The total serum BA concentration was higher in the NAFLD group with worsening of fibrosis than in the HC group. In the serum BA fraction, CA, LCA, and C4 concentrations were significantly higher in the NAFLD than in the HC group. Fecal and serum BA and C4 concentrations were high in patients with NAFLD with worsening of fibrosis, suggesting involvement of abnormal BA metabolism in NAFLD with fibrosis progression. Abnormalities in BA metabolism may be a therapeutic target in NAFLD with fibrosis.

Case-control exercise challenge study on the pathogenesis of high serum gamma-glutamyl transferase activity in racehorses.

High serum γ-glutamyl-transferase (GGT) activity syndrome in racehorses has been associated with maladaption to exercise. Investigation of affected horses before and immediately after standard exercise may provide critical insight into the syndrome's pathophysiology. To investigate blood biomarker changes in actively competing racehorses with high GGT activity associated with an exercise challenge. Case-control study. High GGT case (age: 2-3 years) and normal GGT control (age: 2-7 years) pairs (3 Thoroughbred, 4 Standardbred pairs) at least 3months into their training/racing season were included. Horses with a recent history of high GGT activity (≥50 IU/L) without additional biochemical evidence of liver disease were identified by veterinarians. Horses were tested again in the week prior to a planned exercise challenge to confirm persistent increases in GGT activity. Controls from the same stable with similar training/racing intensity and serum GGT activity ≤36 IU/L were matched with each case. Blood samples were obtained immediately before, 15 and 120 min after exercise. Pre-exercise serum samples were analysed for baseline select serum chemistries, selenium and vitamin E concentrations. Cortisol concentration and markers of oxidative status were measured in serum or plasma for all time points. Individual serum bile acid and coenzyme Q10 concentrations, plasma lipid mediator (fatty acids, oxylipids, isoprostanes) concentrations and targeted metabolomics analyses were performed using liquid chromatography-mass spectrometry. Serum viral PCR for equine hepaci- and parvovirus was performed in each animal. Cases had higher baseline concentrations of total glutathione, taurocholic acid, cortisol and cholesterol concentrations and higher or lower concentrations of specific oxylipid and isoprostane mediators, but there were no case-dependent changes after exercise. Small sample size. Results indicated that glutathione metabolism was altered in high GGT horses. Enhanced glutathione recycling and mild cholestasis are possible explanations for the observed differences.

Chitin-glucan supplementation improved postprandial metabolism and altered gut microbiota in subjects at cardiometabolic risk in a randomized trial

Chitin-glucan (CG), an insoluble dietary fiber, has been shown to improve cardiometabolic disorders associated with obesity in mice. Its effects in healthy subjects has recently been studied, revealing its interaction with the gut microbiota. In this double-blind, randomized, cross-over, twice 3-week exploratory study, we investigated the impacts of CG on the cardiometabolic profile and gut microbiota composition and functions in 15 subjects at cardiometabolic risk. They consumed as a supplement 4.5 g of CG daily or maltodextrin as control. Before and after interventions, fasting and postprandial metabolic parameters and exhaled gases (hydrogen [H2] and methane [CH4]) were evaluated. Gut microbiota composition (16S rRNA gene sequencing analysis), fecal concentrations of bile acids, long- and short-chain fatty acids (LCFA, SCFA), zonulin, calprotectin and lipopolysaccharide binding protein (LBP) were analyzed. Compared to control, CG supplementation increased exhaled H2 following an enriched-fiber breakfast ingestion and decreased postprandial glycemia and triglyceridemia response to a standardized test meal challenge served at lunch. Of note, the decrease in postprandial glycemia was only observed in subjects with higher exhaled H2, assessed upon lactulose breath test performed at inclusion. CG decreased a family belonging to Actinobacteria phylum and increased 3 bacterial taxa: Erysipelotrichaceae UCG.003, Ruminococcaceae UCG.005 and Eubacterium ventriosum group. Fecal metabolites, inflammatory and intestinal permeability markers did not differ between groups. In conclusion, we showed that CG supplementation modified the gut microbiota composition and improved postprandial glycemic response, an early determinant of cardiometabolic risk. Our results also suggest breath H2 production as a non-invasive parameter of interest for predicting the effectiveness of dietary fiber intervention.

Safety Evaluation of Porcine Bile Acids in Laying Hens: Effects on Laying Performance, Egg Quality, Blood Parameters, Organ Indexes, and Intestinal Development

Bile acids (BAs) have long been known to facilitate digestion, transport, and absorption of lipids in the small intestine as well as regulate host lipid metabolic homeostasis. However, excessive BAs may lead to long-term damage to tissue. Also, it is unknown whether different levels of porcine BAs supplementation could improve performance, host metabolism, intestinal functions in laying hens. Hence, this study was aimed to investigate the potential effects of BAs addition on laying performance, egg quality, blood parameters, organ indexes, and intestinal histopathology of hens in the late phase. A total of 300 58-week-old Hy-line Gray hens were randomly divided into five groups which fed a basal diet (control) or basal diets supplemented with 60, 300, 600, and 3,000 mg/kg BAs for 56 days. Compared with the control group, no significant differences (P > 0.05) were observed in egg production, egg weight, ADFI, and FCR of hens in 60, 300, 600, and 3,000 mg/kg BAs groups. Dietary 60 mg/kg BAs supplementation resulted in a significant increase (P < 0.05) in egg mass. Meanwhile, no significant differences were observed in egg quality, including eggshell strength, eggshell thickness, albumen height, and Haugh unit among any treatment groups (P > 0.05). Dramatically, dietary 3,000 mg/kg BAs supplement decreased yolk color (P < 0.05). There was no significant difference in the blood parameters such as WBC, RBC, HGB, HCT, and PLT among any treatments. However, in 3,000 mg/kg BAs group, ovary coefficient was lower than the control (P < 0.05), and serum urea and creatinine were higher than the control (P < 0.05). Also, kidney and oviduct injury appeared in 3,000 mg/kg BAs group. These results indicated that a porcine BAs concentration of 3,000 mg/kg may cause harmful effects while 600 mg/kg was non-deleterious to laying hens after a daily administration for 56 days, namely that dietary supplement of up to 10 times the recommended dose of BAs was safely tolerated by laying hens.

Abnormal gut microbiota and bile acids in patients with first-episode major depressive disorder and correlation analysis.

Gut microbiota and its metabolite bile acids may play a significant role in the occurrence and development of major depressive disorder (MDD). Therefore, this study analyzes gut microbiota and bile acids, as well as their correlation in patients. Thirty-one patients with MDD and 29 healthy controls (HCs) were enrolled in this study. We collected their both blood and feces. Plasma bile acid content was determined by liquid chromatography-mass spectrometry and gut microbiota was detected by 16SrRNA gene sequencing and subsequently analyzed. We also analyzed the correlation between different gut microbiota, bile acids, and Hamilton Depression (HAMD) score. The α-diversity analysis found that Simpson and Pielou evenness index was much higher in HCs than in the patients with MDD. The β-diversity of the two groups were differences by nonmetric multidimensional scaling analysis. Linear discriminant analysis effect size analysis identified 16 different strains. Bile acids detection showed that 23-nordeoxycholic acid in patients with MDD was significantly higher than in HCs, whereas taurolithocholic acid (TLCA), glycolithocholic acid (GLCA), and lithocholic acid 3-sulfate were significantly lower. Spearman correlation analysis showed that Turicibacteraceae, Turicibacterales, and Turicibacter were positively related with TLCA, GLCA, glycodeoxycholic acid (GDCA), and taurodeoxycholic acid, and were negatively correlated with HAMD score. At the same time, TLCA, GLCA, and GDCA were negatively correlated with HAMD score. Gut microbiota and bile acids metabolism are disturbances in MDD, and there exists a correlation between gut microbiota and bile acids metabolism. Moreover, their interaction may be related to the pathophysiological mechanism of MDD.

Altered serum bile acid profile in fibromyalgia is associated with specific gut microbiome changes and symptom severity.

Alterations in the composition and function of the gut microbiome in women with fibromyalgia have recently been demonstrated, including changes in the relative abundance of certain bile acid-metabolizing bacteria. Bile acids can affect multiple physiological processes, including visceral pain, but have yet to be explored for association to the fibromyalgia gut microbiome. In this study, 16S rRNA sequencing and targeted metabolomic approaches were used to characterize the gut microbiome and circulating bile acids in a cohort of 42 women with fibromyalgia and 42 healthy controls. Alterations in the relative abundance of several bacterial species known to metabolize bile acids were observed in women with fibromyalgia, accompanied by significant alterations in the serum concentration of secondary bile acids, including a marked depletion of α-muricholic acid. Statistical learning algorithms could accurately detect individuals with fibromyalgia using the concentration of these serum bile acids. Serum α-muricholic acid was highly correlated with symptom severity, including pain intensity and fatigue. Taken together, these findings suggest serum bile acid alterations are implicated in nociplastic pain. The changes observed in the composition of the gut microbiota and the concentration of circulating secondary bile acids seem congruent with the phenotype of increased nociception and are quantitatively correlated with symptom severity. This is a first demonstration of circulating bile acid alteration in individuals with fibromyalgia, potentially secondary to upstream gut microbiome alterations. If corroborated in independent studies, these observations may allow for the development of molecular diagnostic aids for fibromyalgia as well as mechanistic insights into the syndrome.

The effects of brewers’ spent grain on high-fat diet-induced fatty liver

Obesity drives nonalcoholic fatty liver disease (NAFLD). This study investigated the effects of dietary brewers’ spent grain (BSG) supplementation on obesity-induced NAFLD. Mice fed a high-fat diet supplemented with 30% BSG (HFD30) had reduced body weight and decreased plasma total cholesterol (TC) concentrations compared with HFD-fed mice. Retroperitoneal white adipose tissue (RWAT) and liver weights were reduced. Consistent with reduced hepatic triacylglycerol, TC, and non-esterified fatty acid concentrations, HFD30-fed mice showed reduced hepatic steatosis. 3-hydroxy-3-methylglutaryl-CoA reductase and low-density lipoprotein receptor genes were increased, whereas carnitine palmitoyltransferase 1 alpha, ATP-binding cassette subfamily A member 1 (Abca1), and cholesterol 7 alpha-hydroxylase genes were upregulated in the liver of HFD30-fed mice. Abca1 gene expression was also increased in epididymal WAT and RWAT of HFD30-fed mice. BSG supplementation increased and decreased fecal fat and bile acid concentrations, respectively. Taken together, BSG supplementation reduced HFD-induced hepatic lipid accumulation by increasing fatty acid oxidation and bile acid synthesis in the liver as well as decreasing lipid absorption in the intestine.

Comparative Study of Pyloromyotomy and H-M Pyloroplasty in Proximal Gastrectomy for Adenocarcinoma of Esophageal-Gastric Junction

IntroductionThe incidence of adenocarcinoma of esophageal-gastric junction (AEJ) has been increasing in recent years. Esophagogastrostomy after proximal gastrectomy (PG-EG) is the most commonly used surgical method for this disease which causes a constant spasm of the pyloric sphincter by cutting the vagus nerve around the esophagus, so H-M pyloroplasty (Heineke-Mikulicz pyloroplasty) is often operated after PG-EG to prevent delayed gastric emptying. However, H-M pyloroplasty destroys anti-reflux structure of pylorus and leads to serious bile reflux. The present study was designed to compare pyloromyotomy and H-M pyloroplasty in proximal subtotal gastrectomy through clinical studies and animal experiments. MethodsWe retrospectively evaluated the outcomes of 73 AEJ patients (39 underwent PG-EG with an H-M pyloroplasty and 34 underwent PG-EG with a pyloromyotomy) between January 2016 and August 2020, and perioperative variables were compared. In the animal experiment, 48 rats were randomly divided into four groups (n = 12): vagotomy group (V group), H-M pyloroplasty group (HM group), pyloromyotomy group (PM group), and control group (O group). Gastric emptying and bile reflux were evaluated in each group. ResultsIn the retrospective clinic study, pyloromyotomy and H-M pyloroplasty could all prevent delayed gastric emptying effectively, and the incidence of bile reflux found by electronic gastroscopy in the PM group was significantly lower than that in the HM group (HM, 14/39; PM, 4/34; P = 0.028). In the animal experiment, there was no significant between-group difference of gastric emptying rate (%) in the HM group and PM group (HM, 70.6 ± 16; PM, 72.3 ± 12; P = 0.68) while the gastric emptying rate (%) was significantly lower in the V group than in the HM, PM, and control group (P values were 0.037, 0.021, and 0.001 respectively). The gastric mucosa bile acid concentration was significantly higher in the HM group than other group (P values were all less than 0.001). ConclusionsThe pyloromyotomy could prevent delayed gastric emptying effectively after PG-EG for types II and III AEJ and reduce bile reflux compared to Heineke-Mikulicz pyloroplasty.

Autophagic flux inhibition, apoptosis, and mitochondrial dysfunction in bile acids‐induced impairment of human placental trophoblast

Intrahepatic cholestasis of pregnancy (ICP) is a common pregnancy-specific disease, characterized by increased bile acid levels and adverse fetal outcomes. We previously reported excessive bile acids led to dysfunction of placental trophoblasts in ICP. However, the detailed mechanism is still unclear. Autophagy is fundamental process for protecting cell survival against adverse conditions. Here, we evaluated the effect of increased concentration of bile acids on autophagy in trophoblasts in vitro and in vivo. First, we demonstrated that the autophagy substrate p62/sequestosome-1 was accumulated in placental tissues from patients with ICP and in human trophoblasts treated with hydrophobic bile acids, including chenodeoxycholic acid and deoxycholic acid. Furthermore, we found that treatment with hydrophobic bile acids impaired autophagic flux in both time- and concentration-dependent manners, by suppressing the AMP-activated protein kinase/unc-51-like kinase 1 autophagic signaling pathway. Notably, trophoblasts were prone to apoptotic cell death upon starvation along with bile-acids treatment in vitro or in an ICP mouse model in vivo. Additionally, we revealed mitochondrial dysfunction was the predominant biological process in excessive bile acids induced trophoblast impairment under starvation by proteomic assay. Collectively, our study proposed a complex interaction of excessive bile acids induced autophagic flux, mitochondrial dysfunction, and cellular apoptosis in placental trophoblasts may play a critical role in the pathogenesis of ICP.

The role of bile acid measurement in the management of intrahepatic cholestasis of pregnancy

Introduction: Intrahepatic cholestasis of pregnancy complicates 1% of pregnancies. It increases the risk of severe fetal complications significantly, including preterm delivery and stillbirth. Objective: To summarize our experience with serum total bile acid level measurement that has recently become available for clinical routine in Hungary, and to present the way of gestational cholestasis care at our university. Patients and method: In a retrospective case series, we analyse the data of 12 patients suffering from severe cholestasis of pregnancy treated between September 2020 and September 2021 at the Department of Obstetrics and Gynecology, University of Debrecen. We also determine the statistical correlation between bile acid, transaminase and bilirubin levels in severe cholestasis. Results: 1258 serum samples of 758 patients were measured. 5 of them (0.7% of all cases, 6.4% of cholestasis cases) had severe (total bile acid 40-99 mu mol/L), 7 (0.9% of all cases and 9.0% of cholestasis cases) had very severe (total bile acid >= 100 mu mol/L) disease. The average age of the 12 cases was 30.6 (21-43) years, 7 of them were primigravid. 5 of the patients had a predisposing disease in their history. 6/12 patients received ursodeoxycholic acid treatment, resulting in significant decrease in the bile acid concentrations. Bile acid and GOT (R-2 = 0,14) and bile acid and GPT (R-2 = 0,17) correlations were found to be week in severe cholestasis (n = 45). Postpartum bile acid levels showed rapid improvement. So far, 11 of the patients have delivered and 13 neonates were born, 2/12 were multiple pregnancies. Average gestational age at delivery was 37 (33-40) weeks. 3/11 (27%) were preterm deliveries. 7/8 (88%) of term deliveries were induced. Elective cesarean delivery was not indicated in any of the cases, and in only 2/11 (18%) of the cases did emergency cesarean sections become necessary during labour. No stillbirth occurred. Conclusion: Serum total bile acid measurement is an effective tool in the diagnosis and follow-up of intrahepatic cholestasis of pregnancy, and is inevitable for the protocoll-based obstetrical management of patients. We also present the local protocol of our Department for the management of obstetrical cholestasis.

Taurocholic acid, a primary 12α-hydroxylated bile acid, induces leakiness in the distal small intestine in rats

A high-fat diet increases 12α-hydroxylated (12αOH) bile acid (BA) secretion in rats, and secondary BAs are responsible for the leaky gut. This study aimed to examine the role of primary 12αOH BAs in gut barrier impairment in rats using dietary cholic acid (CA) supplementation (0.5 g/kg diet). The CA diet increased the 12αOH BAs concentrations in the small and large intestine, accompanied by gut barrier impairment. Based on the luminal 12αOH BAs concentrations, ex vivo gut leakiness was determined. Deoxycholic acid increased permeability in the large intestine, whereas taurocholic acid (TCA) increased the ileal permeability, but not jejunal permeability. A Rho kinase inhibitor attenuated TCA-induced ileal permeability. Administration of vancomycin, which abolishes secondary BAs, did not influence the gut leakiness induced by the CA diet. Changes in the gut permeation marker in the tail vein blood suggested the possibility that the CA-induced leakiness occurred in the small intestine. The CA diet enhanced the phosphorylation of myosin light chain 2 and reduced claudins expressions in rat ileal epithelia. Reductions in barrier function-related genes were observed in the ileum, but not in the colon of the CA-fed rats. Overall, the present study demonstrated the significance of TCA in proximal gut leakiness.

The Relationship Between Gut Microbiome and Bile Acids in Primates With Diverse Diets.

Primates have evolved a variety of feeding habits and intestinal physiological structure. Gut microbiome act as metabolic organs in many biological processes and play a vital role in adaptation to dietary niches. Gut microbiome also convert primary bile acids (BAs) to secondary. BAs profile and gut microbiome are together influenced by diets and play a significant role in nutrient absorption. The regulation between gut microbiome and BAs metabolism is bidirectional although the relationship in primates consuming diverse diets is still unclear. Here, we investigated gut microbiome structures, fecal BAs profile, and their relationship in primates preferring three distinct diets. We found that gut microbiome communities are well differentiated among dietary groups. Folivorous primates had higher Firmicutes abundance and lower Prevotella to Bacaeroides ratios, possibly related to fiber consumption. Frugivorous primates are colonized predominantly by Prevotella and Bacteroides, pointing to an increased adaptation to high-sugar and simple carbohydrate diets. Likewise, BA profiles differ according to diet in a manner predictable from the known effects of BAs on metabolism. Folivorous primates have high conjugated bile acid levels and low unconjugated to conjugated BA ratios, consistent with their fiber-rich leaf-eating diet. Much of the differentiation in secondary and unconjugated BAs is associated with microbiome composition shifts and individual bile acid concentrations are correlated with the abundance of distinct bacterial taxonomic groups. Omnivores have higher concentrations of secondary BAs, mainly lithocholic acid (LCA). These levels are significantly positively correlated with the presence of Clostrida species, showing that the digestion requirements of omnivores are different from plant-eating primates. In conclusion, gut microbiome and BAs can respond to changes in diet and are associated with nutrient component consumption in each diet primate group. Our study is the first to demonstrate BA profile differentiation among primates preferring diverse diets. BAs thus appear to work with gut microbiome to help primates adapt to their diet.

Glucose- and Bile Acid-Stimulated Secretion of Gut Hormones in the Isolated Perfused Intestine Is Not Impaired in Diet-Induced Obese Mice.

PurposeDecreased circulating levels of food-intake-regulating gut hormones have been observed in type 2 diabetes and obesity. However, it is still unknown if this is due to decreased secretion from the gut mucosal cells or due to extra-intestinal processing of hormones.MethodsWe measured intestinal hormone content and assessed morphological differences in the intestinal mucosa by histology and immunohistochemistry. Secretion of hormones and absorption of glucose and bile acids (BA) were assessed in isolated perfused mouse intestine.ResultsGIP (glucose-dependent insulinotropic polypeptide) and SS (somatostatin) contents were higher in the duodenum of control mice (p < 0.001, and <0.01). Duodenal GLP-1 (glucagon-like peptide-1) content (p < 0.01) and distal ileum PYY content were higher in DIO mice (p < 0.05). Villus height in the jejunum, crypt depth, and villus height in the ileum were increased in DIO mice (p < 0.05 and p = 0.001). In the distal ileum of DIO mice, more immunoreactive GLP-1 and PYY cells were observed (p = 0.01 and 0.007). There was no difference in the absorption of glucose and bile acids. Distal secretion of SS tended to be higher in DIO mice (p < 0.058), whereas no difference was observed for the other hormones in response to glucose or bile acids.ConclusionOur data suggest that differences regarding production and secretion are unlikely to be responsible for the altered circulating gut hormone levels in obesity, since enteroendocrine morphology and hormone secretion capacity were largely unaffected in DIO mice.

Using targeted LC‐MS/MS‐based metabolomics to measure a broad constellation of bile acids/salts in disorders of human health

BackgroundBile is an important liver secretion which aids the digestion of fats in the intestine. Bile acids are the major organic solute component of bile and are synthesized from cholesterol in the liver and stored in the gallbladder. After secretion in the intestine, bile acids are re‐absorbed in the distal small intestine (ileum). Imbalances in the reabsorption of bile acids can lead to bile acid diarrhea when bile acid malabsorption occurs. Conversely, when there is an increase in bile acid absorption hepatic disorders such as nonalcoholic fatty liver disease can arise. A wide array of distinct bile acid structures have been identified in vertebrates. Developing and refining experimental tools to identify the role of bile acids in health and disease will enhance our ability to treat complex disorders impacting multiple organ systems.Methods &amp; ResultsWe have expanded our existing reverse‐phase liquid chromatography‐tandem mass spectrometry (LC‐MS/MS)‐based targeted metabolomics method to accommodate a simple‐to‐use standards kit that includes reference standards for 16 bile acids/salts and their corresponding deuterated isotopologs as internal standards. LC‐MS/MS method enhancements include scheduled Selected‐Reaction Monitoring (sSRM) to reduce instrument duty cycle, and carefully tailored chromatographic conditions to resolve the following groups of structurally similar or isobaric bile acids/salts: i) Glycocholic Acid (GCA) and Taurocholic Acid (TCA); ii) Lithocholic Acid (LCA), Glycolithocholic Acid (GLCA), and Taurolithocholic Acid (TLCA); iii) isobaric Cholic Acid (CA) and beta‐Muricholic Acid (b‐MCA); iv) isobaric Ursodeoxycholic Acid (UDCA), Chenodeoxycholic Acid (CDCA), and Deoxycholic Acid (DCA); v) isobaric Glycoursodeoxycholic Acid (GUDCA), Glycochenodeoxycholic Acid (GCDCA), and Glycodeoxycholic Acid (GDCA); and vi) isobaric Tauroursodeoxycholic Acid (TUDCA), Taurochenodeoxycholic Acid (TCDCA), and Taurodeoxycholic Acid (TDCA). Our tissue processing and metabolite extraction procedures have been optimized for hepatic and fecal tissues. Individuals with inactivating mutations in the molecular motor, Myosin Vb, have severe diarrhea and often present with liver cholestasis. We used an animal model of loss of Myosin Vb to determine alterations in bile acid composition in the distal small intestine and liver. Whole segments of the ileum and liver were processed in methanol and analyzed by LC‐MS/MS.ConclusionWe have developed a targeted metabolomics method to accurately identify and quantify bile acids by LC‐MS/MS and this technique can be used to investigate changes in bile acid composition in gastrointestinal disorders.

Inhibition of Ileal Bile Acid Transport is Protective Against Cholestatic Liver Injury in Cyp2c70‐/‐Mice with Humanized Bile Acid Composition

Cyp2c70 is the key murine liver enzyme responsible for the synthesis of 6‐hydroxylated muricholates. Cyp2c70 knockout (2c70‐/‐) mice present with a more human‐like bile acid (BA) composition devoid of protective, hydrophilic muricholic acids and with features of cholestatic liver injury. Pharmacological inhibition of the ileal BA transporter (IBAT) has been shown to be protective in cholestatic models such as the Mdr2‐/‐ mouse. The aims of this study were to determine if IBAT inhibition is protective in 2c70‐/‐ mice and identify the underlying molecular mechanisms.Methods2c70‐/‐ mice (C57Bl/6J) were generated using CRISPR/Cas9 technology. Male and female wild type (WT) and 2c70‐/‐ mice were fed chow or chow containing 0.006% SC‐435 for 9 weeks following weaning at 3 weeks of age. Standard growth parameters were recorded; organs, gallbladder bile and blood were collected at necropsy for histologic, RNA and biochemical analyses.ResultsMale and female 2c70‐/‐ mice maintained on chow diet exhibited increased levels of serum liver injury markers ALT, AST, and BAs compared to WT mice. Evaluation of 2c70‐/‐ liver histology revealed increased hepatic inflammation, macrophage infiltration and bilary cell proliferation, which were markedly reduced with SC‐435 treatment. IBAT inhibition in 2c70‐/‐ mice improved liver histology, and reduced hepatic inflammation and bilary cell proliferation to levels indistinguishable from WT. The liver BA content was increased by 53% in 2c70‐/‐ mice, and was enriched in more hydrophobic BA species with an overall hydrophobicity similar that of humans (Figure 1). Treating 2c70‐/‐ mice with SC‐435 reduced the hepatic BA burden by 61%, but did not affect the overall hydrophobicity. RNA‐Seq and KEGG pathway analysis performed using liver RNA revealed genes involved in hepatic steroid and lipid metabolism (Sult2a1, Sult1e1, Hsd17b7), and detoxification (Cyp2c39, Cyp2c54, Cyp2c59, Cyp3a41a/b) were down‐regulated in 2c70‐/‐ mice and their expression were rescued with SC‐435 treatment. Conversely, genes in pathways related to immune cell activation and inflammation were significantly up‐regulated in 2c70‐/‐ mice and reduced to WT levels with IBAT inhibition (Figure 2).ConclusionsOur findings indicate that reducing the hepatic BA burden without altering the hydrophobic compostion is sufficient to protect 2c70‐/‐ mice from hepatic injury. The findings suggest that there may be a threshold in liver for pathological accretion of hydrophobic BAs and reducing the hepatic BA pool is sufficient to alleviate liver injury, independent of hydrophobicity. Moreover, these data support the inhibition IBAT activity, and other approaches to reduce hepatic return of BAs in the enterohepatic circulation, as therapeutic targets to treat cholestasis.

MP05-12 DEPENDENT ANTIBIOTIC AND OXALATE INTERACTIONS IMPACT ATHEROSCLEROSIS AND CALCIUM OXALATE STONES IN THE KIDNEYS

You have accessJournal of UrologyCME1 May 2022MP05-12 DEPENDENT ANTIBIOTIC AND OXALATE INTERACTIONS IMPACT ATHEROSCLEROSIS AND CALCIUM OXALATE STONES IN THE KIDNEYS Jose Agudelo, Lucas Osborn, Beckey DeLucia, Mark Brown, Ava Adler, Jan Claesen, Jane Nguyen, and Aaron Miller Jose AgudeloJose Agudelo More articles by this author , Lucas OsbornLucas Osborn More articles by this author , Beckey DeLuciaBeckey DeLucia More articles by this author , Mark BrownMark Brown More articles by this author , Ava AdlerAva Adler More articles by this author , Jan ClaesenJan Claesen More articles by this author , Jane NguyenJane Nguyen More articles by this author , and Aaron MillerAaron Miller More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002522.12AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Previous studies have shown a positive relationship between cardiometabolic syndrome and increased risk of urinary stone disease (USD). However, the underlying mechanisms that leads to these co-morbidities are unknown. In the current study, we aimed to determine microbiome and diet dependent effects on an atherosclerosis and calcium oxalate stone formation in a mouse model. METHODS: Sixty-six female ApoE null mice were randomly assigned to either a basal diet or 3% oxalate diet. Half of the animals received antibiotic water and the other half sterile water. Mice consumed diets ad libitum for 12-weeks. At the end of the trial, fecal pellets were collected for 16S rRNA quantification. Mice were necropsied, and kidneys, aortas and liver were collected. Kidneys and aortas underwent polarized light quantification of oxalate content. Kidneys were also assessed for oxalate nephropathy after Von Kossa and Alizarin red staining and aortas were assessed for atherosclerosis plaque quantification. Livers were used for bile acid content assessment. Results were compared on a one-way and two-way ANOVA analyses. RESULTS: Bile acid production was significantly impacted by both oxalate and antibiotics. Renal histopathological analysis revealed that oxalate led to an increase in dilated tubules, oxalate nephropathy and tubular injury metrics, which was exacerbated with antibiotic use. Total atherosclerotic plaque lesions in the aortas and the presence of calcium oxalate in the plaque was significantly higher in the group that received dietary oxalate, which again was exacerbated by antibiotic use. CONCLUSIONS: Our results support the hypothesis that exogenous sources of oxalate may lead to both kidney stones and atherosclerosis through the formation of calcium oxalate plaques, which is exacerbated by a loss of function dysbiosis driven by long-term antibiotic use. Importantly, given the clear and significant formation of kidney stones, the APOE mice may serve as a more appropriate mouse model for kidney stones that what has previously been used. Source of Funding: Seed Funding Lerner Research Institute. Urology Care Foundation Research Scholar Award © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e72 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jose Agudelo More articles by this author Lucas Osborn More articles by this author Beckey DeLucia More articles by this author Mark Brown More articles by this author Ava Adler More articles by this author Jan Claesen More articles by this author Jane Nguyen More articles by this author Aaron Miller More articles by this author Expand All Advertisement PDF DownloadLoading ...