Binding of bile acids by pastry products containing bioactive substances during in vitro digestion.

PubMed

Dziedzic, Krzysztof; Górecka, Danuta; Szwengiel, Artur; Smoczyńska, Paulina; Czaczyk, Katarzyna; Komolka, Patrycja

2015-03-01

The modern day consumer tends to choose products with health enhancing properties, enriched in bioactive substances. One such bioactive food component is dietary fibre, which shows a number of physiological properties including the binding of bile acids. Dietary fibre should be contained in everyday, easily accessible food products. Therefore, the aim of this study was to determine sorption capacities of primary bile acid (cholic acid - CA) and secondary bile acids (deoxycholic - DCA and lithocholic acids - LCA) by muffins (BM) and cookies (BC) with bioactive substances and control muffins (CM) and cookies (CC) in two sections of the in vitro gastrointestinal tract. Variations in gut flora were also analysed in the process of in vitro digestion of pastry products in a bioreactor. Enzymes: pepsin, pancreatin and bile salts: cholic acid, deoxycholic acid and lithocholic acid were added to the culture. Faecal bacteria, isolated from human large intestine, were added in the section of large intestine. The influence of dietary fibre content in cookies and concentration of bile acids in two stages of digestion were analysed. Generally, pastry goods with bioactive substances were characterized by a higher content of total fibre compared with the control samples. These products also differ in the profile of dietary fibre fractions. Principal Component Analysis (PCA) showed that the bile acid profile after two stages of digestion depends on the quality and quantity of fibre. The bile acid profile after digestion of BM and BC forms one cluster, and with the CM and CC forms a separate cluster. High concentration of H (hemicellulose) is positively correlated with LCA (low binding effect) and negatively correlated with CA and DCA contents. The relative content of bile acids in the second stage of digestion was in some cases above the content in the control sample, particularly LCA. This means that the bacteria introduced in the 2nd stage of digestion synthesize the LCA.

Towards the elucidation of molecular determinants of cooperativity in the liver bile acid binding protein.

PubMed

Pedò, Massimo; D'Onofrio, Mariapina; Ferranti, Pasquale; Molinari, Henriette; Assfalg, Michael

2009-11-15

Bile acid binding proteins (BABPs) are cytosolic lipid chaperones contributing to the maintenance of bile acid homeostasis and functional distribution within the cell. Liver BABPs act in parallel with ileal transporters to ensure vectorial transport of bile salts in hepatocytes and enterocytes, respectively. We describe the investigation of ligand binding to liver BABP, an essential step in the understanding of intracellular bile salt transport. Binding site occupancies were monitored in NMR titration experiments using (15)N-labelled ligand, while the relative populations of differently bound BABP forms were assessed by mass spectrometry. This site-specific information allowed the determination of intrinsic thermodynamic parameters and the identification of an extremely high cooperativity between two binding sites. Protein-observed NMR experiments revealed a global structural rearrangement which suggests an allosteric mechanism at the basis of the observed cooperativity. The view of a molecular tool capable of buffering against significant concentrations of free bile salts in a large range of solution conditions emerges from the observed pH-dependence of binding. We set to determine the molecular determinants of cooperativity by analysing the binding properties of a protein containing a mutated internal histidine. Both mass spectrometry and NMR experiments are consistent with an overall decreased binding affinity of the mutant, while the measured diffusion coefficients of ligand species reveal that the affinity loss concerns essentially one of the two binding sites. We therefore identified a mutation able to disrupt energetic communication functional to efficient binding and conclude that the buried histidine establishes contacts that stabilize the ternary complex. 2009 Wiley-Liss, Inc.

Ursodeoxycholic acid increases low-density lipoprotein binding, uptake and degradation in isolated hamster hepatocytes.

PubMed Central

Bouscarel, B; Fromm, H; Ceryak, S; Cassidy, M M

1991-01-01

Ursodeoxycholic acid (UDCA), in contrast to both chenodeoxycholic acid (CDCA), its 7 alpha-epimer, and lithocholic acid, enhanced receptor-dependent low-density lipoprotein (LDL) uptake and degradation in isolated hamster hepatocytes. The increase in cell-associated LDL was time- and concentration-dependent, with a maximum effect observed at approx. 60 min with 1 mM-UDCA. This increase was not associated with a detergent effect of UDCA, as no significant modifications were observed either in the cellular release of lactate dehydrogenase or in Trypan Blue exclusion. The effect of UDCA was not due to a modification of the LDL particle, but rather was receptor-related. UDCA (1 mM) maximally increased the number of 125I-LDL-binding sites (Bmax.) by 35%, from 176 to 240 ng/mg of protein, without a significant modification of the binding affinity. Furthermore, following proteolytic degradation of the LDL receptor with Pronase, specific LDL binding decreased to the level of non-specific binding, and the effect of UDCA was abolished. Conversely, the trihydroxy 7 beta-hydroxy bile acid ursocholic acid and its 7 alpha-epimer, cholic acid, induced a significant decrease in LDL binding by approx. 15%. The C23 analogue of UDCA (nor-UDCA) and CDCA did not affect LDL binding. On the other hand, UDCA conjugated with either glycine (GUDCA) or taurine (TUDCA), increased LDL binding to the same extent as did the free bile acid. The half maximum time (t1/2) to reach the full effect was 1-2 min for UDCA and TUDCA, while GUDCA had a much slower t1/2 of 8.3 min. Ketoconazole (50 microM), an antifungal agent, increased LDL binding, but this effect was not additive when tested in the presence of 0.7 mM-UDCA. The results of the studies indicate that, in isolated hamster hepatocytes, the UDCA-induced increase in receptor-dependent LDL binding and uptake represents a direct effect of this bile acid. The action of the bile acid is closely related to its specific structural conformation, since UDCA and its conjugates are the only bile acids shown to express this ability thus far. However, certain agents other than bile acids, such as ketoconazole, have a similar effect. Finally, the studies suggest that the recruitment of LDL receptors from a latent pool in the hepatocellular membrane may be the mechanism by which UDCA exerts its direct effect. Images Fig. 6. PMID:1764022

Kinetics of the bile acid transporter and hepatitis B virus receptor Na+/taurocholate cotransporting polypeptide (NTCP) in hepatocytes.

PubMed

König, Alexander; Döring, Barbara; Mohr, Christina; Geipel, Andreas; Geyer, Joachim; Glebe, Dieter

2014-10-01

The human liver bile acid transporter Na(+)/taurocholate cotransporting polypeptide (NTCP) has recently been identified as liver-specific receptor for infection of hepatitis B virus (HBV), which attaches via the myristoylated preS1 (myr-preS1) peptide domain of its large surface protein to NTCP. Since binding of the myr-preS1 peptide to NTCP is an initiating step of HBV infection, we investigated if this process interferes with the physiological bile acid transport function of NTCP. HBV infection, myr-preS1 peptide binding, and bile acid transport assays were performed with primary Tupaia belangeri (PTH) and human (PHH) hepatocytes as well as NTCP-transfected human hepatoma HepG2 cells allowing regulated NTCP expression, in the presence of various bile acids, ezetimibe, and myr-preS1 peptides. The myr-preS1 peptide of HBV inhibited bile acid transport in PTH and PHH as well as in NTCP-expressing HEK293 and HepG2 cells. Inversely, HBV infection of PTH, PHH, and NTCP-transfected HepG2 cells was inhibited in a concentration-dependent manner by taurine and glycine conjugates of cholic acid and ursodeoxycholic acid as well as by ezetimibe. In NTCP-HepG2 cells and PTH, NTCP expression, NTCP transport function, myr-preS1 peptide binding, and HBV infection followed comparable kinetics. Myr-preS1 virus binding to NTCP, necessary for productive HBV infection, interferes with the physiological bile acid transport function of NTCP. Therefore, HBV infection via NTCP may be lockable by NTCP substrates and NTCP-inhibiting drugs. This opens a completely new way for an efficient management of HBV infection by the use of NTCP-directed drugs. Copyright © 2014 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Structural determinants of ligand binding in the ternary complex of human ileal bile acid binding protein with glycocholate and glycochenodeoxycholate obtained from solution NMR.

PubMed

Horváth, Gergő; Bencsura, Ákos; Simon, Ágnes; Tochtrop, Gregory P; DeKoster, Gregory T; Covey, Douglas F; Cistola, David P; Toke, Orsolya

2016-02-01

Besides aiding digestion, bile salts are important signal molecules exhibiting a regulatory role in metabolic processes. Human ileal bile acid binding protein (I-BABP) is an intracellular carrier of bile salts in the epithelial cells of the distal small intestine and has a key role in the enterohepatic circulation of bile salts. Positive binding cooperativity combined with site selectivity of glycocholate and glycochenodeoxycholate, the two most abundant bile salts in the human body, make human I-BABP a unique member of the family of intracellular lipid binding proteins. Solution NMR structure of the ternary complex of human I-BABP with glycocholate and glycochenodeoxycholate reveals an extensive network of hydrogen bonds and hydrophobic interactions stabilizing the bound bile salts. Conformational changes accompanying bile salt binding affects four major regions in the protein including the C/D, E/F and G/H loops as well as the helical segment. Most of these protein regions coincide with a previously described network of millisecond time scale fluctuations in the apo protein, a motion absent in the bound state. Comparison of the heterotypic doubly ligated complex with the unligated form provides further evidence of a conformation selection mechanism of ligand entry. Structural and dynamic aspects of human I-BABP-bile salt interaction are discussed and compared with characteristics of ligand binding in other members of the intracellular lipid binding protein family. The coordinates of the 10 lowest energy structures of the human I-BABP : GCDA : GCA complex as well as the distance restraints used to calculate the final ensemble have been deposited in the Brookhaven Protein Data Bank with accession number 2MM3. © 2015 FEBS.

Viral Entry of Hepatitis B and D Viruses and Bile Salts Transportation Share Common Molecular Determinants on Sodium Taurocholate Cotransporting Polypeptide

PubMed Central

Yan, Huan; Peng, Bo; Liu, Yang; Xu, Guangwei; He, Wenhui; Ren, Bijie; Jing, Zhiyi; Sui, Jianhua

2014-01-01

ABSTRACT The liver bile acids transporter sodium taurocholate cotransporting polypeptide (NTCP) is responsible for the majority of sodium-dependent bile salts uptake by hepatocytes. NTCP also functions as a cellular receptor for viral entry of hepatitis B virus (HBV) and hepatitis D virus (HDV) through a specific interaction between NTCP and the pre-S1 domain of HBV large envelope protein. However, it remains unknown if these two functions of NTCP are independent or if they interfere with each other. Here we show that binding of the pre-S1 domain to human NTCP blocks taurocholate uptake by the receptor; conversely, some bile acid substrates of NTCP inhibit HBV and HDV entry. Mutations of NTCP residues critical for bile salts binding severely impair viral infection by HDV and HBV; to a lesser extent, the residues important for sodium binding also inhibit viral infection. The mutation S267F, corresponding to a single nucleotide polymorphism (SNP) found in about 9% of the East Asian population, renders NTCP without either taurocholate transporting activity or the ability to support HBV or HDV infection in cell culture. These results demonstrate that molecular determinants critical for HBV and HDV entry overlap with that for bile salts uptake by NTCP, indicating that viral infection may interfere with the normal function of NTCP, and bile acids and their derivatives hold the potential for further development into antiviral drugs. IMPORTANCE Human hepatitis B virus (HBV) and its satellite virus, hepatitis D virus (HDV), are important human pathogens. Available therapeutics against HBV are limited, and there is no drug that is clinically available for HDV infection. A liver bile acids transporter (sodium taurocholate cotransporting polypeptide [NTCP]) critical for maintaining homeostasis of bile acids serves as a functional receptor for HBV and HDV. We report here that the NTCP-binding lipopeptide that originates from the first 47 amino acids of the pre-S1 domain of the HBV L protein blocks taurocholate transport. Some bile salts dose dependently inhibit HBV and HDV infection mediated by NTCP; molecular determinants of NTCP critical for HBV and HDV entry overlap with that for bile acids transport. This work advances our understanding of NTCP-mediated HBV and HDV infection in relation to NTCP's physiological function. Our results also suggest that bile acids or their derivatives hold potential for development into novel drugs against HBV and HDV infection. PMID:24390325

Fluorescence properties of Schiff base - N,N‧-bis(salicylidene) - 1,2-Phenylenediamine in presence of bile acid host

NASA Astrophysics Data System (ADS)

Roy, Nayan; Paul, Pradip C.; Singh, T. Sanjoy

2015-05-01

Fluorescence properties of Schiff base - N,N‧-bis(salicylidene) - 1,2-phenylenediamine (LH2) is used to study the micelles formed by aggregation of different important bile acids like cholic acid, deoxycholic acid, chenodeoxycholic acid and glycocholic acid by steady state and picosecond time-resolved fluorescence spectroscopy. The fluorescence band intensity was found out to increase with concomitant red shift with gradual addition of different bile acids. Binding constant of the probe with different bile acids as well as critical micelle concentration was obtained from the variation of fluorescence intensity on increasing concentration of bile acids in the medium. The increase in fluorescence quantum yields, fluorescence decay times and substantial decrease in nonradiative decay rate constants in bile acids micellar environment points to the restricted motion of the fluorophore inside the micellar subdomains.

Kinetic studies of the inhibition of a human liver 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase isozyme by bile acids and anti-inflammatory drugs.

PubMed

Miyabe, Y; Amano, T; Deyashiki, Y; Hara, A; Tsukada, F

1995-01-01

We have investigated the steady-state kinetics for a cytosolic 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase isozyme of human liver and its inhibition by several bile acids and anti-inflammatory drugs such as indomethacin, flufemanic acid and naproxen. Initial velocity and product inhibition studies performed in the NADP(+)-linked (S)-1-indanol oxidation at pH 7.4 were consistent with a sequential ordered mechanism in which NADP+ binds first and leaves last. The bile acids and drugs, competitive inhibitors with respect to the alcohol substrate, exhibited uncompetitive inhibition with respect to the coenzyme, with Ki values less than 1 microM, whereas indomethacin exhibited noncompetitive inhibition (Ki < 24 microM). The kinetics of the inhibition by a mixture of the two inhibitors suggests that bile acids and drugs, except indomethacin, bind to overlapping sites at the active center of the enzyme-coenzyme binary complex.

Key discoveries in bile acid chemistry and biology and their clinical applications: history of the last eight decades

PubMed Central

Hofmann, Alan F.; Hagey, Lee R.

2014-01-01

During the last 80 years there have been extraordinary advances in our knowledge of the chemistry and biology of bile acids. We present here a brief history of the major achievements as we perceive them. Bernal, a physicist, determined the X-ray structure of cholesterol crystals, and his data together with the vast chemical studies of Wieland and Windaus enabled the correct structure of the steroid nucleus to be deduced. Today, C24 and C27 bile acids together with C27 bile alcohols constitute most of the bile acid “family”. Patterns of bile acid hydroxylation and conjugation are summarized. Bile acid measurement encompasses the techniques of GC, HPLC, and MS, as well as enzymatic, bioluminescent, and competitive binding methods. The enterohepatic circulation of bile acids results from vectorial transport of bile acids by the ileal enterocyte and hepatocyte; the key transporters have been cloned. Bile acids are amphipathic, self-associate in solution, and form mixed micelles with polar lipids, phosphatidylcholine in bile, and fatty acids in intestinal content during triglyceride digestion. The rise and decline of dissolution of cholesterol gallstones by the ingestion of 3,7-dihydroxy bile acids is chronicled. Scientists from throughout the world have contributed to these achievements. PMID:24838141

Key discoveries in bile acid chemistry and biology and their clinical applications: history of the last eight decades.

PubMed

Hofmann, Alan F; Hagey, Lee R

2014-08-01

During the last 80 years there have been extraordinary advances in our knowledge of the chemistry and biology of bile acids. We present here a brief history of the major achievements as we perceive them. Bernal, a physicist, determined the X-ray structure of cholesterol crystals, and his data together with the vast chemical studies of Wieland and Windaus enabled the correct structure of the steroid nucleus to be deduced. Today, C24 and C27 bile acids together with C27 bile alcohols constitute most of the bile acid "family". Patterns of bile acid hydroxylation and conjugation are summarized. Bile acid measurement encompasses the techniques of GC, HPLC, and MS, as well as enzymatic, bioluminescent, and competitive binding methods. The enterohepatic circulation of bile acids results from vectorial transport of bile acids by the ileal enterocyte and hepatocyte; the key transporters have been cloned. Bile acids are amphipathic, self-associate in solution, and form mixed micelles with polar lipids, phosphatidylcholine in bile, and fatty acids in intestinal content during triglyceride digestion. The rise and decline of dissolution of cholesterol gallstones by the ingestion of 3,7-dihydroxy bile acids is chronicled. Scientists from throughout the world have contributed to these achievements. Copyright © 2014 by the American Society for Biochemistry and Molecular Biology, Inc.

Crystal structure of axolotl (Ambystoma mexicanum) liver bile acid-binding protein bound to cholic and oleic acid.

PubMed

Capaldi, Stefano; Guariento, Mara; Perduca, Massimiliano; Di Pietro, Santiago M; Santomé, José A; Monaco, Hugo L

2006-07-01

The family of the liver bile acid-binding proteins (L-BABPs), formerly called liver basic fatty acid-binding proteins (Lb-FABPs) shares fold and sequence similarity with the paralogous liver fatty acid-binding proteins (L-FABPs) but has a different stoichiometry and specificity of ligand binding. This article describes the first X-ray structure of a member of the L-BABP family, axolotl (Ambystoma mexicanum) L-BABP, bound to two different ligands: cholic and oleic acid. The protein binds one molecule of oleic acid in a position that is significantly different from that of either of the two molecules that bind to rat liver FABP. The stoichiometry of binding of cholate is of two ligands per protein molecule, as observed in chicken L-BABP. The cholate molecule that binds buried most deeply into the internal cavity overlaps well with the analogous bound to chicken L-BABP, whereas the second molecule, which interacts with the first only through hydrophobic contacts, is more external and exposed to the solvent. (c) 2006 Wiley-Liss, Inc.

The bile acid-sensitive ion channel (BASIC) is activated by alterations of its membrane environment.

PubMed

Schmidt, Axel; Lenzig, Pia; Oslender-Bujotzek, Adrienne; Kusch, Jana; Lucas, Susana Dias; Gründer, Stefan; Wiemuth, Dominik

2014-01-01

The bile acid-sensitive ion channel (BASIC) is a member of the DEG/ENaC family of ion channels. Channels of this family are characterized by a common structure, their physiological functions and modes of activation, however, are diverse. Rat BASIC is expressed in brain, liver and intestinal tract and activated by bile acids. The physiological function of BASIC and its mechanism of bile acid activation remain a puzzle. Here we addressed the question whether amphiphilic bile acids activate BASIC by directly binding to the channel or indirectly by altering the properties of the surrounding membrane. We show that membrane-active substances other than bile acids also affect the activity of BASIC and that activation by bile acids and other membrane-active substances is non-additive, suggesting that BASIC is sensitive for changes in its membrane environment. Furthermore based on results from chimeras between BASIC and ASIC1a, we show that the extracellular and the transmembrane domains are important for membrane sensitivity.

Multidrug resistance-associated protein 4 is a bile transporter of Clonorchis sinensis simulated by in silico docking.

PubMed

Dai, Fuhong; Yoo, Won Gi; Lee, Ji-Yun; Lu, Yanyan; Pak, Jhang Ho; Sohn, Woon-Mok; Hong, Sung-Jong

2017-11-21

Multidrug resistance-associated protein 4 (MRP4) is a member of the C subfamily of the ABC family of ATP-binding cassette (ABC) transporters. MRP4 regulates ATP-dependent efflux of various organic anionic substrates and bile acids out of cells. Since Clonorchis sinensis lives in host's bile duct, accumulation of bile juice can be toxic to the worm's tissues and cells. Therefore, C. sinensis needs bile transporters to reduce accumulation of bile acids within its body. We cloned MRP4 (CsMRP4) from C. sinensis and obtained a cDNA encoding an open reading frame of 1469 amino acids. Phylogenetic analysis revealed that CsMRP4 belonged to the MRP/SUR/CFTR subfamily. A tertiary structure of CsMRP4 was generated by homology modeling based on multiple structures of MRP1 and P-glycoprotein. CsMRP4 had two membrane-spanning domains (MSD1 & 2) and two nucleotide-binding domains (NBD1 & 2) as common structural folds. Docking simulation with nine bile acids showed that CsMRP4 transports bile acids through the inner cavity. Moreover, it was found that CsMRP4 mRNA was more abundant in the metacercariae than in the adults. Mouse immune serum, generated against the CsMRP4-NBD1 (24.9 kDa) fragment, localized CsMRP4 mainly in mesenchymal tissues and oral and ventral suckers of the metacercariae and the adults. Our findings shed new light on MRPs and their homologs and provide a platform for further structural and functional investigations on the bile transporters and parasites' survival.

Studies on the uptake of fatty acids by brush border membranes of the rabbit intestine.

PubMed

Proulx, P; Aubry, H; Brglez, I; Williamson, D G

1985-04-01

Initial studies revealed that the uptake of palmitic acid and oleic acid into brush border membranes was similar when these were isolated from either whole small intestine, jejunum, or ileum. The uptake of these fatty acids was somewhat lower with membranes obtained from duodenum. Subsequent studies, all with membranes obtained from whole intestine, indicated an increase in binding with chain length of fatty acid of up to 16 carbons. Unsaturation decreased this uptake somewhat. Taurocholate and 1-palmitoyl lysolecithin had a moderate stimulatory effect on the binding of oleic acid and palmitic acid at concentrations of 10 and 0.5 mM, respectively, and inhibited at higher concentrations. Addition of 1.4 mM egg lecithin to the fatty acid - bile salt micelles, such that the lecithin - bile salt ratio was 0.2, decreased the uptake of fatty acids generally, but did not significantly affect the pattern of binding by membrane fractions isolated from different segments nor did it change the pattern of labelling when fatty acid chain length and unsaturation were varied. At lower concentrations, egg lecithin had little effect on the uptake of oleic acid, whereas dipalmitoyl phosphatidylcholine stimulated binding of both palmitic acid and oleic acid over the entire range of concentrations tested. Preincubation of the membranes with this saturated phospholipid stimulated the uptake of oleic acid, and addition of this choline lipid to the oleic acid - bile salt containing micelles did not substantially enhance fatty acid uptake in lipid-treated membranes. The binding of fatty acid was very rapid either in the presence or the absence of Ca2+, such that even in zero-time controls essentially equilibrium bindings were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Techno-functional properties and in vitro bile acid-binding capacities of tamarillo (Solanum betaceum Cav.) hydrocolloids.

PubMed

Gannasin, Sri Puvanesvari; Adzahan, Noranizan Mohd; Mustafa, Shuhaimi; Muhammad, Kharidah

2016-04-01

Hydrocolloids were extracted from seed mucilage and the pulp fractions from red tamarillo (Solanum betaceum Cav.) mesocarp, and characterisation of their techno-functional properties and in vitro bile acid-binding capacities was performed. The seed mucilage hydrocolloids that were extracted, using either 1% citric acid (THC) or water (THW), had a good foaming capacity (32-36%), whereas the pulp hydrocolloids that were extracted, using 72% ethanol (THE) or 20mM HEPES buffer (THH), had no foaming capacity. The pulp hydrocolloid, however, possessed high oil-holding and water-holding capacities in the range of 3.3-3.6 g oil/g dry sample and 25-27 g water/g dry sample, respectively. This enabled the pulp hydrocolloid to entrap more bile acids (35-38% at a hydrocolloid concentration of 2%) in its gelatinous network in comparison to commercial oat fibre and other hydrocolloids studied. The exceptional emulsifying properties (80-96%) of both hydrocolloids suggest their potential applications as food emulsifiers and bile acid binders. Copyright © 2015 Elsevier Ltd. All rights reserved.

Binding domain-driven intracellular trafficking of sterols for synthesis of steroid hormones, bile acids and oxysterols.

PubMed

Midzak, Andrew; Papadopoulos, Vassilios

2014-09-01

Steroid hormones, bioactive oxysterols and bile acids are all derived from the biological metabolism of lipid cholesterol. The enzymatic pathways generating these compounds have been an area of intense research for almost a century, as cholesterol and its metabolites have substantial impacts on human health. Owing to its high degree of hydrophobicity and the chemical properties that it confers to biological membranes, the distribution of cholesterol in cells is tightly controlled, with subcellular organelles exhibiting highly divergent levels of cholesterol. The manners in which cells maintain such sterol distributions are of great interest in the study of steroid and bile acid synthesis, as limiting cholesterol substrate to the enzymatic pathways is the principal mechanism by which production of steroids and bile acids is regulated. The mechanisms by which cholesterol moves within cells, however, remain poorly understood. In this review, we examine the subcellular machinery involved in cholesterol metabolism to steroid hormones and bile acid, relating it to both lipid- and protein-based mechanisms facilitating intracellular and intraorganellar cholesterol movement and delivery to these pathways. In particular, we examine evidence for the involvement of specific protein domains involved in cholesterol binding, which impact cholesterol movement and metabolism in steroidogenesis and bile acid synthesis. A better understanding of the physical mechanisms by which these protein- and lipid-based systems function is of fundamental importance to understanding physiological homeostasis and its perturbation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Genetics Home Reference: intrahepatic cholestasis of pregnancy

MedlinePlus

... such as women of Araucanian Indian ancestry in Chile or women of Scandinavian ancestry. This condition is ... reduce the movement of phospholipids into bile. The lack of phospholipids available to bind to bile acids ...

Reduced hepatitis B and D viral entry using clinically applied drugs as novel inhibitors of the bile acid transporter NTCP.

PubMed

Donkers, Joanne M; Zehnder, Benno; van Westen, Gerard J P; Kwakkenbos, Mark J; IJzerman, Adriaan P; Oude Elferink, Ronald P J; Beuers, Ulrich; Urban, Stephan; van de Graaf, Stan F J

2017-11-10

The sodium taurocholate co-transporting polypeptide (NTCP, SLC10A1) is the main hepatic transporter of conjugated bile acids, and the entry receptor for hepatitis B virus (HBV) and hepatitis delta virus (HDV). Myrcludex B, a synthetic peptide mimicking the NTCP-binding domain of HBV, effectively blocks HBV and HDV infection. In addition, Myrcludex B inhibits NTCP-mediated bile acid uptake, suggesting that also other NTCP inhibitors could potentially be a novel treatment of HBV/HDV infection. This study aims to identify clinically-applied compounds intervening with NTCP-mediated bile acid transport and HBV/HDV infection. 1280 FDA/EMA-approved drugs were screened to identify compounds that reduce uptake of taurocholic acid and lower Myrcludex B-binding in U2OS cells stably expressing human NTCP. HBV/HDV viral entry inhibition was studied in HepaRG cells. The four most potent inhibitors of human NTCP were rosiglitazone (IC 50 5.1 µM), zafirlukast (IC 50 6.5 µM), TRIAC (IC 50 6.9 µM), and sulfasalazine (IC 50 9.6 µM). Chicago sky blue 6B (IC 50 7.1 µM) inhibited both NTCP and ASBT, a distinct though related bile acid transporter. Rosiglitazone, zafirlukast, TRIAC, sulfasalazine, and chicago sky blue 6B reduced HBV/HDV infection in HepaRG cells in a dose-dependent manner. Five out of 1280 clinically approved drugs were identified that inhibit NTCP-mediated bile acid uptake and HBV/HDV infection in vitro.

Managing bile acid diarrhoea

PubMed Central

Walters, Julian R. F.; Pattni, Sanjeev S.

2010-01-01

Bowel symptoms including diarrhoea can be produced when excess bile acids (BA) are present in the colon. This condition, known as bile acid or bile salt malabsorption, has been under recognized, as the best diagnostic method, the 75Se-homocholic acid taurine (SeHCAT) test, is not available in many countries and is not fully utilized in others. Reduced SeHCAT retention establishes that this is a complication of many other gastrointestinal diseases. Repeated studies show SeHCAT tests are abnormal in about 30% of patients otherwise diagnosed as diarrhoea-predominant irritable bowel syndrome or functional diarrhoea, with an estimated population prevalence of around 1%. Recent work suggests that the condition previously called idiopathic bile acid malabsorption (BAM) is not in fact due to a defect in absorption, but results from an overproduction of BA because of defective feedback inhibition of hepatic bile acid synthesis, a function of the ileal hormone fibroblast growth factor 19 (FGF19). The approach to treatment currently depends on binding excess BA, to reduce their secretory actions, using colestyramine, colestipol and, most recently, colesevelam. Colesevelam has a number of potential advantages that merit further investigation in trials directed at patients with bile acid diarrhoea. PMID:21180614

Managing bile acid diarrhoea.

PubMed

Walters, Julian R F; Pattni, Sanjeev S

2010-11-01

Bowel symptoms including diarrhoea can be produced when excess bile acids (BA) are present in the colon. This condition, known as bile acid or bile salt malabsorption, has been under recognized, as the best diagnostic method, the (75)Se-homocholic acid taurine (SeHCAT) test, is not available in many countries and is not fully utilized in others. Reduced SeHCAT retention establishes that this is a complication of many other gastrointestinal diseases. Repeated studies show SeHCAT tests are abnormal in about 30% of patients otherwise diagnosed as diarrhoea-predominant irritable bowel syndrome or functional diarrhoea, with an estimated population prevalence of around 1%. Recent work suggests that the condition previously called idiopathic bile acid malabsorption (BAM) is not in fact due to a defect in absorption, but results from an overproduction of BA because of defective feedback inhibition of hepatic bile acid synthesis, a function of the ileal hormone fibroblast growth factor 19 (FGF19). The approach to treatment currently depends on binding excess BA, to reduce their secretory actions, using colestyramine, colestipol and, most recently, colesevelam. Colesevelam has a number of potential advantages that merit further investigation in trials directed at patients with bile acid diarrhoea.

A Substrate Pharmacophore for the Human Sodium Taurocholate Co-transporting Polypeptide

PubMed Central

Dong, Zhongqi; Ekins, Sean; Polli, James E.

2014-01-01

Human Sodium Taurocholate Co-transporting Polypeptide (NTCP) is the main bile acid uptake transporter in the liver with the capability to translocate xenobiotics. While its inhibitor requirements have been recently characterized, its substrate requirements have not. The objectives of this study were a) to elucidate NTCP substrate requirements using native bile acids and bile acid analogs, b) to develop the first pharmacophore for NTCP substrates and compare it with the inhibitor pharmacophores, and c) to identify additional NTCP novel substrates. Thus, 18 native bile acids and two bile acid conjugates were initially assessed for NTCP inhibition and/or uptake, which suggested a role of hydroxyl pattern and steric interaction in NTCP binding and translocation. A common feature pharmacophore for NTCP substrate uptake was developed, using 14 native bile acids and bile acid conjugates, yielding a model which featured three hydrophobes, one hydrogen bond donor, one negative ionizable feature and three excluded volumes. This model was used to search a database of FDA approved drugs and retrieved the majority of the known NTCP substrates. Among the retrieved drugs, irbesartan and losartan were identified as novel NTCP substrates, suggesting a potential role of NTCP in drug disposition. PMID:25448570

Structural requirements of the human sodium-dependent bile acid transporter (hASBT): Role of 3- and 7-OH moieties on binding and translocation of bile acids

PubMed Central

González, Pablo M.; Lagos, Carlos F.; Ward, Weslyn C.; Polli, James E.

2014-01-01

Bile acids (BAs) are the end products of cholesterol metabolism. One of the critical steps in their biosynthesis involves the isomerization of the 3β-hydroxyl (-OH) group on the cholestane ring to the common 3α-configuration on BAs. BAs are actively recaptured from the small intestine by the human Apical Sodium-dependent Bile Acid Transporter (hASBT) with high affinity and capacity. Previous studies have suggested that no particular hydroxyl group on BAs is critical for binding or transport by hASBT, even though 3β-hydroxylated BAs were not examined. The aim of this study was to elucidate the role of the 3α-OH group on BAs binding and translocation by hASBT. Ten 3β-hydroxylated BAs (Iso-bile acids, iBAs) were synthesized, characterized, and subjected to hASBT inhibition and uptake studies. hASBT inhibition and uptake kinetics of iBAs were compared to that of native 3α-OH BAs. Glycine conjugates of native and isomeric BAs were subjected to molecular dynamics simulations in order to identify topological descriptors related to binding and translocation by hASBT. Iso-BAs bound to hASBT with lower affinity and exhibited reduced translocation than their respective 3α-epimers. Kinetic data suggests that, in contrast to native BAs where hASBT binding is the rate-limiting step, iBAs transport was rate-limited by translocation and not binding. Remarkably, 7-dehydroxylated iBAs were not hASBT substrates, highlighting the critical role of 7-OH group on BA translocation by hASBT, especially for iBAs. Conformational analysis of gly-iBAs and native BAs identified topological features for optimal binding as: concave steroidal nucleus, 3-OH “on-” or below-steroidal plane, 7-OH below-plane, and 12-OH moiety towards-plane. Our results emphasize the relevance of the 3α-OH group on BAs for proper hASBT binding and transport and revealed the critical role of 7-OH group on BA translocation, particularly in the absence of a 3α-OH group. Results have implications for BA prodrug design. PMID:24328955

Fasting induces basolateral uptake transporters of the SLC family in the liver via HNF4alpha and PGC1alpha.

PubMed

Dietrich, Christoph G; Martin, Ina V; Porn, Anne C; Voigt, Sebastian; Gartung, Carsten; Trautwein, Christian; Geier, Andreas

2007-09-01

Fasting induces numerous adaptive changes in metabolism by several central signaling pathways, the most important represented by the HNF4alpha/PGC-1alpha-pathway. Because HNF4alpha has been identified as central regulator of basolateral bile acid transporters and a previous study reports increased basolateral bile acid uptake into the liver during fasting, we hypothesized that HNF4alpha is involved in fasting-induced bile acid uptake via upregulation of basolateral bile acid transporters. In rats, mRNA of Ntcp, Oatp1, and Oatp2 were significantly increased after 48 h of fasting. Protein expression as determined by Western blot showed significant increases for all three transporters 72 h after the onset of fasting. Whereas binding activity of HNF1alpha in electrophoretic mobility shift assays remained unchanged, HNF4alpha binding activity to the Ntcp promoter was increased significantly. In line with this result, we found significantly increased mRNA expression of HNF4alpha and PGC-1alpha. Functional studies in HepG2 cells revealed an increased endogenous NTCP mRNA expression upon cotransfection with either HNF4alpha, PGC-1alpha, or a combination of both. We conclude that upregulation of the basolateral bile acid transporters Ntcp, Oatp1, and Oatp2 in fasted rats is mediated via the HNF4alpha/PGC-1alpha pathway.

Nod2 deficiency protects mice from cholestatic liver disease by increasing renal excretion of bile acids

PubMed Central

Wang, Lirui; Hartmann, Phillipp; Haimerl, Michael; Bathena, Sai P.; Sjöwall, Christopher; Almer, Sven; Alnouti, Yazen; Hofmann, Alan F.; Schnabl, Bernd

2014-01-01

Background & aims Chronic liver disease is characterized by fibrosis that may progress to cirrhosis. Nucleotide oligomerization domain 2 (Nod2), a member of the Nod-like receptor (NLR) family of intracellular immune receptors, plays an important role in the defense against bacterial infection through binding to the ligand muramyl dipeptide (MDP). Here, we investigated the role of Nod2 in the development of liver fibrosis. Methods We studied experimental cholestatic liver disease induced by bile duct ligation or toxic liver disease induced by carbon tetrachloride in wild type and Nod2−/− mice. Results Nod2 deficiency protected mice from cholestatic but not toxin-induced liver injury and fibrosis. Most notably, the hepatic bile acid concentration was lower in Nod2−/− mice than wild type mice following bile duct ligation for 3 weeks. In contrast to wild type mice, Nod2−/− mice had increased urinary excretion of bile acids, including sulfated bile acids, and an upregulation of the bile acid efflux transporters MRP2 and MRP4 in tubular epithelial cells of the kidney. MRP2 and MRP4 were downregulated by IL-1β in a Nod2 dependent fashion. Conclusions Our findings indicate that Nod2 deficiency protects mice from cholestatic liver injury and fibrosis through enhancing renal excretion of bile acids that in turn contributes to decreased concentration of bile acids in the hepatocyte. PMID:24560660

Role of cholangiocyte bile Acid transporters in large bile duct injury after rat liver transplantation.

PubMed

Cheng, Long; Zhao, Lijin; Li, Dajiang; Liu, Zipei; Chen, Geng; Tian, Feng; Li, Xiaowu; Wang, Shuguang

2010-07-27

The pathogenesis of nonanastomotic strictures with a patent hepatic artery remains to be investigated. This study focuses on the role of cholangiocyte bile acid transporters in bile duct injury after liver transplantation. Sprague-Dawley rats were divided into three groups (n=20 for each): the sham-operated group (Sham), the transplant group with 1-hr donor liver cold preservation (CP-1h), and the transplant group with 12-hr donor liver cold preservation (CP-12h). Bile was collected for biochemical analysis. The histopathologic evaluation of bile duct injury was performed and the cholangiocyte bile acid transporters apical sodium-dependent bile acid transporter (ASBT), ileal lipid binding protein (ILBP), and Ostalpha/Ostbeta were investigated. RESULTS.: The immunohistochemical assay suggested that ASBT and ILBP were expressed exclusively on large bile duct epithelial cells, whereas Ostalpha and Ostbeta were expressed on both small and large bile ducts. Western blot and quantitative polymerase chain reaction analysis showed that the expression levels of these transporters dramatically decreased after transplantation. It took seven to 14 days for ILBP, Ostalpha, and Ostbeta to recover, whereas ASBT recovered within 3 days and even reached a peak above the normal level seven days after operation. In the CP-12h group, the ratios of the ASBT/ILBP, ASBT/Ostalpha and ASBT/Ostbeta expression levels were correlated with the injury severity scores of large but not small bile ducts. The results suggest that the unparallel alteration of cholangiocyte bile acid transporters may play a potential role in large bile duct injury after liver transplantation with prolonged donor liver preservation.

[Substrate specificities of bile salt hydrolase 1 and its mutants from Lactobacillus salivarius].

PubMed

Bi, Jie; Fang, Fang; Qiu, Yuying; Yang, Qingli; Chen, Jian

2014-03-01

In order to analyze the correlation between critical residues in the catalytic centre of BSH and the enzyme substrate specificity, seven mutants of Lactobacillus salivarius bile salt hydrolase (BSH1) were constructed by using the Escherichia coli pET-20b(+) gene expression system, rational design and site-directed mutagenesis. These BSH1 mutants exhibited different hydrolytic activities against various conjugated bile salts through substrate specificities comparison. Among the residues being tested, Cys2 and Thr264 were deduced as key sites for BSH1 to catalyze taurocholic acid and glycocholic acid, respectively. Moreover, Cys2 and Thr264 were important for keeping the catalytic activity of BSH1. The high conservative Cys2 was not the only active site, other mutant amino acid sites were possibly involved in substrate binding. These mutant residues might influence the space and shape of the substrate-binding pockets or the channel size for substrate passing through and entering active site of BSH1, thus, the hydrolytic activity of BSH1 was changed to different conjugated bile salt.

Structural basis of the alternating-access mechanism in a bile acid transporter

NASA Astrophysics Data System (ADS)

Zhou, Xiaoming; Levin, Elena J.; Pan, Yaping; McCoy, Jason G.; Sharma, Ruchika; Kloss, Brian; Bruni, Renato; Quick, Matthias; Zhou, Ming

2014-01-01

Bile acids are synthesized from cholesterol in hepatocytes and secreted through the biliary tract into the small intestine, where they aid in absorption of lipids and fat-soluble vitamins. Through a process known as enterohepatic recirculation, more than 90% of secreted bile acids are then retrieved from the intestine and returned to the liver for resecretion. In humans, there are two Na+-dependent bile acid transporters involved in enterohepatic recirculation, the Na+-taurocholate co-transporting polypeptide (NTCP; also known as SLC10A1) expressed in hepatocytes, and the apical sodium-dependent bile acid transporter (ASBT; also known as SLC10A2) expressed on enterocytes in the terminal ileum. In recent years, ASBT has attracted much interest as a potential drug target for treatment of hypercholesterolaemia, because inhibition of ASBT reduces reabsorption of bile acids, thus increasing bile acid synthesis and consequently cholesterol consumption. However, a lack of three-dimensional structures of bile acid transporters hampers our ability to understand the molecular mechanisms of substrate selectivity and transport, and to interpret the wealth of existing functional data. The crystal structure of an ASBT homologue from Neisseria meningitidis (ASBTNM) in detergent was reported recently, showing the protein in an inward-open conformation bound to two Na+ and a taurocholic acid. However, the structural changes that bring bile acid and Na+ across the membrane are difficult to infer from a single structure. To understand the structural changes associated with the coupled transport of Na+ and bile acids, here we solved two structures of an ASBT homologue from Yersinia frederiksenii (ASBTYf) in a lipid environment, which reveal that a large rigid-body rotation of a substrate-binding domain gives the conserved `crossover' region, where two discontinuous helices cross each other, alternating accessibility from either side of the cell membrane. This result has implications for the location and orientation of the bile acid during transport, as well as for the translocation pathway for Na+.

Structural basis of the alternating-access mechanism in a bile acid transporter

PubMed Central

Zhou, Xiaoming; Levin, Elena J.; Pan, Yaping; McCoy, Jason G.; Sharma, Ruchika; Kloss, Brian; Bruni, Renato; Quick, Matthias; Zhou, Ming

2014-01-01

Bile acids are synthesized from cholesterol in hepatocytes and secreted via the biliary tract into the small intestine, where they aid in absorption of lipids and fat-soluble vitamins. Through a process known as enterohepatic recirculation, more than 90% of secreted bile acids are then retrieved from the intestine and returned to the liver for re-secretion1. In humans, there are two Na+-dependent bile acid transporters involved in enterohepatic recirculation, the Na+-taurocholate co-transporting polypeptide (NTCP or SLC10A1) expressed in hepatocytes, and the apical sodium-dependent bile acid transporter (ASBT or SLC10A2) expressed on enterocytes in the terminal ileum2. In recent years, ASBT has attracted much interest as a potential drug target for treatment of hypercholesterolemia, because inhibition of ASBT reduces reabsorption of bile acids, thus increasing bile acid synthesis and consequently cholesterol consumption3,4. However, a lack of 3-dimensional structures of bile acid transporters hampers our ability to understand the molecular mechanisms of substrate selectivity and transport, and to interpret the wealth of existing functional data2,5-8. The crystal structure of an ASBT homolog from Neisseria meningitidis (ASBTNM) in detergent was reported recently9, showing the protein in an inward-open conformation bound to two Na+ and a taurocholic acid. However, the structural changes that bring bile acid and Na+ across the membrane are difficult to infer from a single structure. To understand better the structural changes associated with the coupled transport of Na+ and bile acids, we crystallized and solved two structures of a ASBT homolog from Yersinia frederiksenii (ASBTYf) in a lipid environment, which reveal that a large rigid-body rotation of a substrate-binding domain gives alternate accessibility to the highly conserved “crossover” region, where two discontinuous transmembrane helices cross each other. This result has implications for the location and orientation of the bile acid during transport, as well as for the translocation pathway for Na+. PMID:24317697

Protection of dried probiotic bacteria from bile using bile adsorbent resins.

PubMed

Mahbubani, Krishnaa T; Slater, Nigel K H; Edwards, Alexander D

2014-01-25

Enteric coated oral tablets or capsules can deliver dried live cells directly into the intestine. Previously, we found that a live attenuated bacterial vaccine acquired sensitivity to intestinal bile when dried, raising the possibility that although gastric acid can be bypassed, significant loss of viability might occur on release from an enteric coated oral formulations. Here we demonstrate that some food-grade lyophilised preparations of Lactobacillus casei and Lactobacillus salivarius also show temporary bile sensitivity that can be rapidly reversed by rehydration. To protect dried bacterial cells from temporary bile sensitivity, we propose using bile acid adsorbing resins, such as cholestyramine, which are bile acid binding agents, historically used to lower cholesterol levels. Vcaps™ HPMC capsules alone provided up to 830-fold protection from bile. The inclusion of 50% w/w cholestyramine in Vcaps™ HPMC capsules resulted in release of up to 1700-fold more live Lactobacillus casei into simulated intestinal fluid containing 1% bile, when compared to dried cells added directly to bile. We conclude that delivery of dried live probiotic organisms to the intestine may be improved by providing protection from bile by addition of bile adsorbing resins and the use of HPMC capsules. Copyright © 2013 Elsevier B.V. All rights reserved.

Enzymatic characterization of a novel bovine liver dihydrodiol dehydrogenase--reaction mechanism and bile acid dehydrogenase activity.

PubMed

Nanjo, H; Adachi, H; Morihana, S; Mizoguchi, T; Nishihara, T; Terada, T

1995-05-11

Bovine liver cytosolic dihydrodiol dehydrogenase (DD3) has been characterized by its unique dihydrodiol dehydrogenase activity for trans-benzenedihydrodiol (trans-1,2-dihydrobenzene-1,2-diol) with the highest affinity and the greatest velocity among three multiple forms of dihydrodiol dehydrogenases (DD1-DD3). It is the first time that DD3 has shown a significant dehydrogenase activity for (S)-(+)-1-indanol with low Km value (0.33 +/- 0.022 mM) and high K(cat) value (25 +/- 0.79 min-1). The investigation of the product inhibition of (S)-(+)-1-indanol with NADP+ versus 1-indanone and NADPH clearly showed that the enzymatic reaction of DD3 may follow a typical ordered Bi Bi mechanism similar to many aldo/keto reductases. Additionally, DD3 was shown to catalyze the dehydrogenation of bile acids (lithocholic acid, taurolithocholic acid and taurochenodeoxycholic acid) having no 12-hydroxy groups with low Km values (17 +/- 0.65, 33 +/- 1.9 and 890 +/- 73 microM, respectively). In contrast, DD1, 3 alpha-hydroxysteroid dehydrogenase, shows a broad substrate specificity for many bile acids with higher affinity than those of DD3. Competitive inhibition of DD3 with androsterone against dehydrogenase activity for (S)-(+)-1-indanol, trans-benzenedihydrodiol or lithocholic acid suggests that these three substrates bind to the same substrate binding site of DD3, different from the case of human liver bile acid binder/dihydrodiol dehydrogenase (Takikawa, H., Stolz, A., Sugiyama, Y., Yoshida, H., Yamamoto, M. and Kaplowitz, N. (1990) J. Biol. Chem. 265, 2132-2136). Considering the reaction mechanism, DD3 may also play an important role in bile acids metabolism as well as the detoxication of aromatic hydrocarbons.

NMR unfolding studies on a liver bile acid binding protein reveal a global two-state unfolding and localized singular behaviors.

PubMed

D'Onofrio, Mariapina; Ragona, Laura; Fessas, Dimitrios; Signorelli, Marco; Ugolini, Raffaella; Pedò, Massimo; Assfalg, Michael; Molinari, Henriette

2009-01-01

The folding properties of a bile acid binding protein, belonging to a subfamily of the fatty acid binding proteins, have been here investigated both by hydrogen exchange measurements, using the SOFAST NMR approach, and urea denaturation experiments. The urea unfolding profiles of individual residues, acting as single probes, were simultaneously analyzed through a global fit, according to a two-state unfolding model. The resulting conformational stability DeltaG(U)(H(2)O)=7.2+/-0.25kcal mol(-1) is in good agreement with hydrogen exchange stability DeltaG(op). While the majority of protein residues satisfy this model, few amino-acids display a singular behavior, not directly amenable to the presence of a folding intermediate, as reported for other fatty acid binding proteins. These residues are part of a protein patch characterized by enhanced plasticity. To explain this singular behavior a tentative model has been proposed which takes into account the interplay between the dynamic features and the formation of transient aggregates. A functional role for this plasticity, related to translocation across the nuclear membrane, is discussed.

Studies of the prevalence and significance of radiolabeled bile acid malabsorption in a group of patients with idiopathic chronic diarrhea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiller, L.R.; Hogan, R.B.; Morawski, S.G.

1987-01-01

We studied radiolabeled fecal bile acid excretion in 11 normal subjects and 17 patients with idiopathic chronic diarrhea for three major purposes: to establish normal values for this test in the presence of increased stool volumes (induced in normal subjects by ingestion of poorly absorbable solutions); to test for bile acid malabsorption in the patients and to correlate this with an independent test of ileal function, the Schilling test; and to compare the results of the bile acid excretion test with the subsequent effect of a bile acid binding agent (cholestyramine) on stool weight. In normal subjects fecal excretion ofmore » the radiolabel was increased with increasing stool volumes. As a group, patients with idiopathic chronic diarrhea excreted radiolabeled bile acid more rapidly than normal subjects with induced diarrhea (t1/2 56 +/- 8 vs. 236 +/- 60 h, respectively, p less than 0.005). There was a statistically significant positive correlation between t1/2 of radiolabeled bile acid and Schilling test results in these patients. Although 14 of 17 patients absorbed labeled taurocholic acid less well than any of the normal subjects with comparable volumes of induced diarrhea, cholestyramine had no statistically significant effect on stool weight in the patient group, and in none of the patients was stool weight reduced to within the normal range. In summary, most patients with idiopathic chronic diarrhea have bile acid malabsorption (as measured by fecal excretion of labeled bile acid), but they do not respond to cholestyramine therapy with a significant reduction in stool weight. Although the significance of these findings was not clearly established, the most likely interpretation is that bile acid malabsorption is a manifestation of an underlying intestinal motility or absorptive defect rather than the primary cause of diarrhea.« less

Bile acids and their oxo derivatives: Potential inhibitors of carbonic anhydrase I and II, androgen receptor antagonists and CYP3A4 substrates.

PubMed

Trifunović, Jovana; Borčić, Vladan; Mikov, Momir

2017-05-01

Some biological properties of bile acids and their oxo derivatives have not been sufficiently investigated, although the interest in bile acids as signaling molecules is rising. The aim of this work was to evaluate physico-chemical parametar b (slope) that represents the lipophilicity of the examined molecules and to investigate interactions of bile acids with carbonic anhydrase I, II, androgen receptor and CYP450s. Thirteen candidates were investigated using normal-phase thin-layer chromatography in two solvent systems. Retention parameters were used in further quantitative structure-activity relationship analysis and docking studies to predict interactions and binding affinities of examined molecules with enzymes and receptors. Prediction of activity on androgen receptor showed that compounds 3α-hydroxy-12-oxo-5β-cholanoic and 3α-hydroxy-7-oxo-5β-cholanoic acid have stronger antiandrogen activity than natural bile acids. The inhibitory potential for carbonic anhydrase I and II was tested and it was concluded that molecules 3α-hydroxy-12-oxo-5β-cholanoic, 3α-hydroxy-7-oxo-5β-cholanoic, 3,7,12-trioxo-5β-cholanoic acid and hyodeoxycholic acid show the best results. Substrate behavior for CYP3A4 was confirmed for all investigated compounds. Oxo derivatives of bile acids show stronger interactions with enzymes and receptors as classical bile acids and lower membranolytic activity compared with them. These significant observations could be valuable in consideration of oxo derivatives as building blocks in medicinal chemistry. Copyright © 2016 John Wiley & Sons, Ltd.

Characterization of the Physicochemical Properties of β-Cyclodextrin-Divinyl Sulfone Polymer Carrier-Bile Acid Systems.

PubMed

Mohamed, Mohamed H; Wang, Chen; Peru, Kerry M; Headley, John V; Wilson, Lee D

2017-08-07

Herein, we report on the systematic design and characterization of cross-linked polymer carriers containing β-cyclodextrin (β-CD) and divinyl sulfone (DVS). The polymer carriers were prepared at variable feed ratios (β-CD-DVS; 1:1, 1:2, 1:3, and 1:6) and characterized using spectroscopy (IR, 1 H solution NMR, and 13 C CP-MAS solids NMR spectroscopy), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and a dye decolorization method using phenolphthalein. Uptake studies were carried out at pH 9.00 for the polymer carriers using single component bile acids (cholic acid, deoxycholic acid, glycodeoxycholic acid, and taurodeoxycholic acid). Equilibrium uptake results were evaluated by the Langmuir isotherm model where variable equilibrium parameters were related to the relative apolar character of the bile acid. The Langmuir model yields a carrier/bile acid binding affinity of ∼10 3 M -1 where the lipophilic inclusion sites of the polymer play a prominent role, while the DVS linker framework sites have a lower adsorption affinity, in accordance with the greater hydrophilic character of such sites.

The influence of NaCl on hydrophobicity of selected, pharmacologically active bile acids expressed with chromatographic retention index and critical micellar concentration.

PubMed

Posa, Mihalj; Pilipović, Ana; Lalić, Mladena

2010-11-01

Many of bile acids' (BA) physiological properties, as receptor binding, activation of ionic channels, binding to blood proteins, etc. are due to their hydrophobicity. On the other hand, hydrophobicity determines BAs' physico-chemical characteristics as micelle forming and adsorption (surface activity). However, BA hydrophobicity is not determined solely by their structure. Medium composition, especially the concentration of electrolytes has influence on BA hydrophobicity. Thus, the objective of this work was to examine the effect of NaCl on hydrophobicity of selected bile acids. This influence is specified with the retention factor k (reversed phase high pressure liquid chromatography (RPHPLC)) and critical micellar concentration (CMC) determined by non-invasive NMR method. The value of lnk elevates with the increase in mobile phase NaCl concentration i.e. Deltalnk/Deltac(NaCl) depends on the number of water molecules not stabilised by hydrogen bonds in bile acid hydration sheath. For bile acids that contain hydroxyl groups (except those with beta equatorial hydroxyl groups) the value of |DeltalnCMC/Deltac(NaCl)| rises with the increase in the number of non-stabilized water molecules in their hydration sheath. Even though oxo derivatives of cholic acid have similar chromatographic parameters they behave differently when it comes to CMC. In fact with the introduction of oxo groups the value of its |DeltalnCMC/Deltac(NaCl)| elevates but it results in a decrease in the number of non-stabilized water molecules i.e. hydrophobicity falls. Different behaviour of oxo derivatives implicate that, besides "hydrophobic interactions" in their micelles, there are also hydrogen bonds i.e. fiord effect exists. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Hypolipidemic mechanism of oryzanol components- ferulic acid and phytosterols.

PubMed

Bhaskaragoud, G; Rajath, S; Mahendra, V P; Kumar, G Sunil; Gopala Krishna, A G; Kumar, G Suresh

2016-07-22

The effect of oryzanol (well known hypolipidemic component in rice bran oil) and its chemical constituents- ferulic acid (FA) and phytosterols on hypolipidemia were investigated. Docking (in silico) studies showed that FA had a better binding ability with lipase while sterols bound well with HMG-CoA reductase. Further in vivo studies of feeding high fat (30%) to rats increased body weights, serum TC, TG, non-HDL-C and reduced HDL-C were observed, compared to normal diet fed group (ND). ORZ treated groups alleviated the lipid profile. Furthermore, increased organ weights, higher intestinal lipase activity, and liver lipid peroxidation was observed in the high-fat group (HF). These effects were ameliorated in oryzanol concentrate fed groups (ORZ). Higher fecal fat was found in ORZ groups, analysis of fecal matter by mass spectroscopy revealed the presence of FA. In vitro, a bile acid binding study supported the strong affinity of sterol towards bile acids. In conclusion, oryzanol in the intestine is cleaved into FA and sterol by intestinal lipase enzymes both lipase and HMG-CoA reductase activities were inhibited, respectively. These hydrolysates eliminated the bile acids, thus lowering lipid profiles. Copyright © 2016 Elsevier Inc. All rights reserved.

Conformational and dynamics changes induced by bile acids binding to chicken liver bile acid binding protein.

PubMed

Eberini, Ivano; Guerini Rocco, Alessandro; Ientile, Anna Rita; Baptista, António M; Gianazza, Elisabetta; Tomaselli, Simona; Molinari, Henriette; Ragona, Laura

2008-06-01

The correlation between protein motions and function is a central problem in protein science. Several studies have demonstrated that ligand binding and protein dynamics are strongly correlated in intracellular lipid binding proteins (iLBPs), in which the high degree of flexibility, principally occurring at the level of helix-II, CD, and EF loops (the so-called portal area), is significantly reduced upon ligand binding. We have recently investigated by NMR the dynamic properties of a member of the iLBP family, chicken liver bile acid binding protein (cL-BABP), in its apo and holo form, as a complex with two bile salts molecules. Binding was found to be regulated by a dynamic process and a conformational rearrangement was associated with this event. We report here the results of molecular dynamics (MD) simulations performed on apo and holo cL-BABP with the aim of further characterizing the protein regions involved in motion propagation and of evaluating the main molecular interactions stabilizing bound ligands. Upon binding, the root mean square fluctuation values substantially decrease for CD and EF loops while increase for the helix-loop-helix region, thus indicating that the portal area is the region mostly affected by complex formation. These results nicely correlate with backbone dynamics data derived from NMR experiments. Essential dynamics analysis of the MD trajectories indicates that the major concerted motions involve the three contiguous structural elements of the portal area, which however are dynamically coupled in different ways whether in the presence or in the absence of the ligands. Motions of the EF loop and of the helical region are part of the essential space of both apo and holo-BABP and sample a much wider conformational space in the apo form. Together with NMR results, these data support the view that, in the apo protein, the flexible EF loop visits many conformational states including those typical of the holo state and that the ligand acts stabilizing one of these pre-existing conformations. The present results, in agreement with data reported for other iLBPs, sharpen our knowledge on the binding mechanism for this protein family. (c) 2008 Wiley-Liss, Inc.

Hyodeoxycholic acid derivatives as liver X receptor α and G-protein-coupled bile acid receptor agonists

NASA Astrophysics Data System (ADS)

de Marino, Simona; Carino, Adriana; Masullo, Dario; Finamore, Claudia; Marchianò, Silvia; Cipriani, Sabrina; di Leva, Francesco Saverio; Catalanotti, Bruno; Novellino, Ettore; Limongelli, Vittorio; Fiorucci, Stefano; Zampella, Angela

2017-02-01

Bile acids are extensively investigated for their potential in the treatment of human disorders. The liver X receptors (LXRs), activated by oxysterols and by a secondary bile acid named hyodeoxycholic acid (HDCA), have been found essential in the regulation of lipid homeostasis in mammals. Unfortunately, LXRα activates lipogenic enzymes causing accumulation of lipid in the liver. In addition to LXRs, HDCA has been also shown to function as ligand for GPBAR1, a G protein coupled receptor for secondary bile acids whose activation represents a promising approach to liver steatosis. In the present study, we report a library of HDCA derivatives endowed with modulatory activity on the two receptors. The lead optimization of HDCA moiety was rationally driven by the structural information on the binding site of the two targets and results from pharmacological characterization allowed the identification of hyodeoxycholane derivatives with selective agonistic activity toward LXRα and GPBAR1 and notably to the identification of the first example of potent dual LXRα/GPBAR1 agonists. The new chemical entities might hold utility in the treatment of dyslipidemic disorders.

Impact of beta-cyclodextrin and resistant starch on bile acid metabolism and fecal steroid excretion in regard to their hypolipidemic action in hamsters.

PubMed

Trautwein, E A; Forgbert, K; Rieckhoff, D; Erbersdobler, H F

1999-01-29

To examine the impact on bile acid metabolism and fecal steroid excretion as a mechanism involved in the lipid-lowering action of beta-cyclodextrin and resistant starch in comparison to cholestyramine, male golden Syrian hamsters were fed 0% (control), 8% or 12% of beta-cyclodextrin or resistant starch or 1% cholestyramine. Resistant starch, beta-cyclodextrin and cholestyramine significantly lowered plasma total cholesterol and triacylglycerol concentrations compared to control. Distinct changes in the bile acid profile of gallbladder bile were caused by resistant starch, beta-cyclodextrin and cholestyramine. While cholestyramine significantly reduced chenodeoxycholate independently of its taurine-glycine conjugation, beta-cyclodextrin and resistant starch decreased especially the percentage of taurochenodeoxycholate by -75% and -44%, respectively. As a result, the cholate:chenodeoxycholate ratio was significantly increased by 100% with beta-cyclodextrin and by 550% with cholestyramine while resistant starch revealed no effect on this ratio. beta-Cyclodextrin and resistant starch, not cholestyramine, significantly increased the glycine:taurine conjugation ratio demonstrating the predominance of glycine conjugated bile acids. Daily fecal excretion of bile acids was 4-times higher with 8% beta-cyclodextrin and 19-times with 1% cholestyramine compared to control. beta-Cyclodextrin and cholestyramine also induced a 2-fold increase in fecal neutral sterol excretion, demonstrating the sterol binding capacity of these two compounds. Resistant starch had only a modest effect on fecal bile acid excretion (80% increase) and no effect on excretion of neutral sterols, suggesting a weak interaction with intestinal steroid absorption. These data demonstrate the lipid-lowering potential of beta-cyclodextrin and resistant starch. An impaired reabsorption of circulating bile acids and intestinal cholesterol absorption leading to an increase in fecal bile acid and neutral sterol excretion is most likely the primary mechanism responsible for the lipid-lowering action of beta-cyclodextrin. In contrast, other mechanisms involving the alterations in the biliary bile acid profile or repressed hepatic lipogenesis, e.g., VLDL production, appear to be involved in the hypolipidemic effect of resistant starch.

Orphan nuclear receptor oestrogen-related receptor γ (ERRγ) plays a key role in hepatic cannabinoid receptor type 1-mediated induction of CYP7A1 gene expression

PubMed Central

Zhang, Yaochen; Kim, Don-Kyu; Lee, Ji-Min; Park, Seung Bum; Jeong, Won-IL; Kim, Seong Heon; Lee, In-Kyu; Lee, Chul-Ho; Chiang, John Y.L.; Choi, Hueng-Sik

2017-01-01

Bile acids are primarily synthesized from cholesterol in the liver and have important roles in dietary lipid absorption and cholesterol homoeostasis. Detailed roles of the orphan nuclear receptors regulating cholesterol 7α-hydroxylase (CYP7A1), the rate-limiting enzyme in bile acid synthesis, have not yet been fully elucidated. In the present study, we report that oestrogen-related receptor γ (ERRγ) is a novel transcriptional regulator of CYP7A1 expression. Activation of cannabinoid receptor type 1 (CB1 receptor) signalling induced ERRγ-mediated transcription of the CYP7A1 gene. Overexpression of ERRγ increased CYP7A1 expression in vitro and in vivo, whereas knockdown of ERRγ attenuated CYP7A1 expression. Deletion analysis of the CYP7A1 gene promoter and a ChIP assay revealed an ERRγ -binding site on the CYP7A1 gene promoter. Small heterodimer partner (SHP) inhibited the transcriptional activity of ERRγ and thus regulated CYP7A1 expression. Overexpression of ERRγ led to increased bile acid levels, whereas an inverse agonist of ERRγ, GSK5182, reduced CYP7A1 expression and bile acid synthesis. Finally, GSK5182 significantly reduced hepatic CB1 receptor-mediated induction of CYP7A1 expression and bile acid synthesis in alcohol-treated mice. These results provide the molecular mechanism linking ERRγ and bile acid metabolism. PMID:26348907

Improvement of impaired albumin binding capacity in acute-on-chronic liver failure by albumin dialysis.

PubMed

Klammt, Sebastian; Mitzner, Steffen R; Stange, Jan; Loock, Jan; Heemann, Uwe; Emmrich, Jörg; Reisinger, Emil C; Schmidt, Reinhard

2008-09-01

Extracorporeal albumin dialysis (ECAD) enables the elimination of albumin bound substances and is used as artificial liver support system. Albumin binding function for the benzodiazepine binding site specific marker Dansylsarcosine was estimated in plasma samples of 22 patients with cirrhosis and hyperbilirubinaemia (ECAD: n = 12; control: n = 10) during a period of 30 days in a randomized controlled clinical ECAD trial. Albumin Binding Capacity (ABiC) at baseline was reduced to 31.8% (median; range 24%-74%) and correlated to the severity of liver disease. Within two weeks a significant improvement of ABiC and a reduction of the albumin bound markers bilirubin and bile acids were observed in the ECAD group. During single treatments a significant decrease of albumin bound substances (bilirubin and bile acids) as well as an increase in ABiC was observed. In the control group, baseline ABiC was significantly lower in patients who died during study period (34.2% vs. 41.7%; P < 0.028), whereas no significant differences were observed for CHILD, coagulation factors, albumin, bile acids nor bilirubin. At baseline 13 patients had a severely impaired ABiC (<40%), improvement of ABiC was more frequent in the ECAD group (5/6) than in the SMT group (2/7). Reduced albumin binding function is present in decompensated liver failure and is related to severity and 30 day survival. ABiC can be improved by ECAD. The beneficial effect of this treatment may be related to the improvement of albumin binding function more than to the elimination of specific substances. Characterization of albumin function by the ABiC test may help to evaluate different liver support systems and other therapeutic measures.

Hepatic Deletion of SIRT1 Decreases Hepatocyte Nuclear Factor 1α/Farnesoid X Receptor Signaling and Induces Formation of Cholesterol Gallstones in Mice

PubMed Central

Purushotham, Aparna; Xu, Qing; Lu, Jing; Foley, Julie F.; Yan, Xingjian; Kim, Dong-Hyun; Kemper, Jongsook Kim

2012-01-01

SIRT1, a highly conserved NAD+-dependent protein deacetylase, is a key metabolic sensor that directly links nutrient signals to animal metabolic homeostasis. Although SIRT1 has been implicated in a number of hepatic metabolic processes, the mechanisms by which hepatic SIRT1 modulates bile acid metabolism are still not well understood. Here we report that deletion of hepatic SIRT1 reduces the expression of farnesoid X receptor (FXR), a nuclear receptor that regulates bile acid homeostasis. We provide evidence that SIRT1 regulates the expression of FXR through hepatocyte nuclear factor 1α (HNF1α). SIRT1 deficiency in hepatocytes leads to decreased binding of HNF1α to the FXR promoter. Furthermore, we show that hepatocyte-specific deletion of SIRT1 leads to derangements in bile acid metabolism, predisposing the mice to development of cholesterol gallstones on a lithogenic diet. Taken together, our findings indicate that SIRT1 plays a vital role in the regulation of hepatic bile acid homeostasis through the HNF1α/FXR signaling pathway. PMID:22290433

Structural elucidation of the hormonal inhibition mechanism of the bile acid cholate on human carbonic anhydrase II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boone, Christopher D.; Tu, Chingkuang; McKenna, Robert, E-mail: rmckenna@ufl.edu

The structure of human carbonic anhydrase II in complex with cholate has been determined to 1.54 Å resolution. Elucidation of the novel inhibition mechanism of cholate will aid in the development of a nonsulfur-containing, isoform-specific therapeutic agent. The carbonic anhydrases (CAs) are a family of mostly zinc metalloenzymes that catalyze the reversible hydration/dehydration of CO{sub 2} into bicarbonate and a proton. Human isoform CA II (HCA II) is abundant in the surface epithelial cells of the gastric mucosa, where it serves an important role in cytoprotection through bicarbonate secretion. Physiological inhibition of HCA II via the bile acids contributes tomore » mucosal injury in ulcerogenic conditions. This study details the weak biophysical interactions associated with the binding of a primary bile acid, cholate, to HCA II. The X-ray crystallographic structure determined to 1.54 Å resolution revealed that cholate does not make any direct hydrogen-bond interactions with HCA II, but instead reconfigures the well ordered water network within the active site to promote indirect binding to the enzyme. Structural knowledge of the binding interactions of this nonsulfur-containing inhibitor with HCA II could provide the template design for high-affinity, isoform-specific therapeutic agents for a variety of diseases/pathological states, including cancer, glaucoma, epilepsy and osteoporosis.« less

Characterization of Lactic Acid Bacteria as Poultry Probiotic Candidates with Aflatoxin B1 Binding Activities

NASA Astrophysics Data System (ADS)

Damayanti, E.; Istiqomah, L.; Saragih, J. E.; Purwoko, T.; Sardjono

2017-12-01

Our previous studies have selected lactic acid bacteria (LAB) with antifungal activities from traditional fermented foods made from cassava (G7) and silage feed palm leaf (PDS5 and PDS3). In this study we evaluated their ability to bind aflatoxin B1 (AFB1) and probiotic characteristic. The probiotic characteristic assays of LAB consisted of resistance to acidic conditions (pH 3), gastric juice and bile salts 0.3%. We also carried out an in vitro evaluation of LAB aflatoxin binding ability in viable and non-viable cell for 24 and 48 hours of incubation. The measurement of aflatoxin content was performed by ELISA method using AgraQuant Total Aflatoxin Assay kit. The results showed that all isolates were potential as probiotics and the G7 isolate had the highest viability among other isolates in pH 3 (92.61 %) and the bile salts assay (97.71 %). The percentage of aflatoxin reduction between viable and non-viable cell from each LAB isolate were different. The highest aflatoxin reduction in viable cell assay was performed by G7 isolate (69.11 %) whereas in non-viable cell assay was performed by PDS3 isolate (73.75 %) during incubation time 48 hours. In this study, G7 isolate performed the best probiotic characteristics with the highest viability in acid pH assay, bile salt 0.3% assay and percentage of aflatoxin B1 reduction in viable cell condition. Molecular identification using 16S rRNA sequence analysis showed that G7 isolate had homology with Lactobacillus plantarum (99.9%). It was concluded that Lactobacillus plantarum G7 was potential as probiotic with aflatoxin binding activities.

Impact of ursodeoxycholic acid on a CCK1R cholesterol-binding site may contribute to its positive effects in digestive function

PubMed Central

Desai, Aditya J.; Dong, Maoqing; Harikumar, Kaleeckal G.

2015-01-01

Dysfunction of the type 1 cholecystokinin (CCK) receptor (CCK1R) as a result of increased gallbladder muscularis membrane cholesterol has been implicated in the pathogenesis of cholesterol gallstones. Administration of ursodeoxycholic acid, which is structurally related to cholesterol, has been shown to have beneficial effects on gallstone formation. Our aims were to explore the possible direct effects and mechanism of action of bile acids on CCK receptor function. We studied the effects of structurally related hydrophobic chenodeoxycholic acid and hydrophilic ursodeoxycholic acid in vitro on CCK receptor function in the setting of normal and elevated membrane cholesterol. We also examined their effects on a cholesterol-insensitive CCK1R mutant (Y140A) disrupting a key site of cholesterol action. The results show that, similar to the impact of cholesterol on CCK receptors, bile acid effects were limited to CCK1R, with no effects on CCK2R. Chenodeoxycholic acid had a negative impact on CCK1R function, while ursodeoxycholic acid had no effect on CCK1R function in normal membranes but was protective against the negative impact of elevated cholesterol on this receptor. The cholesterol-insensitive CCK1R mutant Y140A was resistant to effects of both bile acids. These data suggest that bile acids compete with the action of cholesterol on CCK1R, probably by interacting at the same site, although the conformational impact of each bile acid appears to be different, with ursodeoxycholic acid capable of correcting the abnormal conformation of CCK1R in a high-cholesterol environment. This mechanism may contribute to the beneficial effect of ursodeoxycholic acid in reducing cholesterol gallstone formation. PMID:26138469

Impact of ursodeoxycholic acid on a CCK1R cholesterol-binding site may contribute to its positive effects in digestive function.

PubMed

Desai, Aditya J; Dong, Maoqing; Harikumar, Kaleeckal G; Miller, Laurence J

2015-09-01

Dysfunction of the type 1 cholecystokinin (CCK) receptor (CCK1R) as a result of increased gallbladder muscularis membrane cholesterol has been implicated in the pathogenesis of cholesterol gallstones. Administration of ursodeoxycholic acid, which is structurally related to cholesterol, has been shown to have beneficial effects on gallstone formation. Our aims were to explore the possible direct effects and mechanism of action of bile acids on CCK receptor function. We studied the effects of structurally related hydrophobic chenodeoxycholic acid and hydrophilic ursodeoxycholic acid in vitro on CCK receptor function in the setting of normal and elevated membrane cholesterol. We also examined their effects on a cholesterol-insensitive CCK1R mutant (Y140A) disrupting a key site of cholesterol action. The results show that, similar to the impact of cholesterol on CCK receptors, bile acid effects were limited to CCK1R, with no effects on CCK2R. Chenodeoxycholic acid had a negative impact on CCK1R function, while ursodeoxycholic acid had no effect on CCK1R function in normal membranes but was protective against the negative impact of elevated cholesterol on this receptor. The cholesterol-insensitive CCK1R mutant Y140A was resistant to effects of both bile acids. These data suggest that bile acids compete with the action of cholesterol on CCK1R, probably by interacting at the same site, although the conformational impact of each bile acid appears to be different, with ursodeoxycholic acid capable of correcting the abnormal conformation of CCK1R in a high-cholesterol environment. This mechanism may contribute to the beneficial effect of ursodeoxycholic acid in reducing cholesterol gallstone formation. Copyright © 2015 the American Physiological Society.

Screening, Characterization and In Vitro Evaluation of Probiotic Properties Among Lactic Acid Bacteria Through Comparative Analysis.

PubMed

Devi, Sundru Manjulata; Archer, Ann Catherine; Halami, Prakash M

2015-09-01

The present work aimed to identify probiotic bacteria from healthy human infant faecal and dairy samples. Subsequently, an assay was developed to evaluate the probiotic properties using comparative genetic approach for marker genes involved in adhesion to the intestinal epithelial layer. Several in vitro properties including tolerance to biological barriers (such as acid and bile), antimicrobial spectrum, resistance to simulated digestive fluids and cellular hydrophobicity were assessed. The potential probiotic cultures were rapidly characterized by morphological, physiological and molecular-based methods [such as RFLP, ITS, RAPD and (GTG)5]. Further analysis by 16S rDNA sequencing revealed that the selected isolates belong to Lactobacillus, Pediococcus and Enterococcus species. Two cultures of non-lactic, non-pathogenic Staphylococcus spp. were also isolated. The native isolates were able to survive under acidic, bile and simulated intestinal conditions. In addition, these cultures inhibited the growth of tested bacterial pathogens. Further, no correlation was observed between hydrophobicity and adhesion ability. Sequencing of probiotic marker genes such as bile salt hydrolase (bsh), fibronectin-binding protein (fbp) and mucin-binding protein (mub) for selected isolates revealed nucleotide variation. The probiotic binding domains were detected by several bioinformatic tools. The approach used in the study enabled the identification of potential probiotic domains responsible for adhesion of bacteria to intestinal epithelial layer, which may further assist in screening of novel probiotic bacteria. The rapid detection of binding domains will help in revealing the beneficial properties of the probiotic cultures. Further, studies will be performed to develop a novel probiotic product which will contribute in food and feed industry.

Bile Acid-regulated Peroxisome Proliferator-activated Receptor-α (PPARα) Activity Underlies Circadian Expression of Intestinal Peptide Absorption Transporter PepT1/Slc15a1*

PubMed Central

Okamura, Ayako; Koyanagi, Satoru; Dilxiat, Adila; Kusunose, Naoki; Chen, Jia Jun; Matsunaga, Naoya; Shibata, Shigenobu; Ohdo, Shigehiro

2014-01-01

Digested proteins are mainly absorbed as small peptides composed of two or three amino acids. The intestinal absorption of small peptides is mediated via only one transport system: the proton-coupled peptide transporter-1 (PepT1) encoded from the soluble carrier protein Slc15a1. In mammals, intestinal expression of PepT1/Slc15a1 oscillates during the daily feeding cycle. Although the oscillation in the intestinal expression of PepT1/Slc15a1 is suggested to be controlled by molecular components of circadian clock, we demonstrated here that bile acids regulated the oscillation of PepT1/Slc15a1 expression through modulating the activity of peroxisome proliferator-activated receptor α (PPARα). Nocturnally active mice mainly consumed their food during the dark phase. PPARα activated the intestinal expression of Slc15a1 mRNA during the light period, and protein levels of PepT1 peaked before the start of the dark phase. After food intake, bile acids accumulated in intestinal epithelial cells. Intestinal accumulated bile acids interfered with recruitment of co-transcriptional activator CREB-binding protein/p300 on the promoter region of Slc15a1 gene, thereby suppressing PPARα-mediated transactivation of Slc15a1. The time-dependent suppression of PPARα-mediated transactivation by bile acids caused an oscillation in the intestinal expression of PepT1/Slc15a1 during the daily feeding cycle that led to circadian changes in the intestinal absorption of small peptides. These findings suggest a molecular clock-independent mechanism by which bile acid-regulated PPARα activity governs the circadian expression of intestinal peptide transporter. PMID:25016014

Liver-selective glucocorticoid antagonists: a novel treatment for type 2 diabetes.

PubMed

von Geldern, Thomas W; Tu, Noah; Kym, Philip R; Link, James T; Jae, Hwan-Soo; Lai, Chunqiu; Apelqvist, Theresa; Rhonnstad, Patrik; Hagberg, Lars; Koehler, Konrad; Grynfarb, Marlena; Goos-Nilsson, Annika; Sandberg, Johnny; Osterlund, Marie; Barkhem, Tomas; Höglund, Marie; Wang, Jiahong; Fung, Steven; Wilcox, Denise; Nguyen, Phong; Jakob, Clarissa; Hutchins, Charles; Färnegårdh, Mathias; Kauppi, Björn; Ohman, Lars; Jacobson, Peer B

2004-08-12

Hepatic blockade of glucocorticoid receptors (GR) suppresses glucose production and thus decreases circulating glucose levels, but systemic glucocorticoid antagonism can produce adrenal insufficiency and other undesirable side effects. These hepatic and systemic responses might be dissected, leading to liver-selective pharmacology, when a GR antagonist is linked to a bile acid in an appropriate manner. Bile acid conjugation can be accomplished with a minimal loss of binding affinity for GR. The resultant conjugates remain potent in cell-based functional assays. A novel in vivo assay has been developed to simultaneously evaluate both hepatic and systemic GR blockade; this assay has been used to optimize the nature and site of the linker functionality, as well as the choice of the GR antagonist and the bile acid. This optimization led to the identification of A-348441, which reduces glucose levels and improves lipid profiles in an animal model of diabetes. Copyright 2004 American Chemical Society

Intracellular cholesterol transport proteins enhance hydrolysis of HDL-CEs and facilitate elimination of cholesterol into bile.

PubMed

Wang, Jing; Bie, Jinghua; Ghosh, Shobha

2016-09-01

While HDL-associated unesterified or free cholesterol (FC) is thought to be rapidly secreted into the bile, the fate of HDL-associated cholesteryl esters (HDL-CEs) that represent >80% of HDL-cholesterol, is only beginning to be understood. In the present study, we examined the hypothesis that intracellular cholesterol transport proteins [sterol carrier protein 2 (SCP2) and fatty acid binding protein-1 (FABP1)] not only facilitate CE hydrolase-mediated hydrolysis of HDL-CEs, but also enhance elimination of cholesterol into bile. Adenovirus-mediated overexpression of FABP1 or SCP2 in primary hepatocytes significantly increased hydrolysis of HDL-[(3)H]CE, reduced resecretion of HDL-CE-derived FC as nascent HDL, and increased its secretion as bile acids. Consistently, the flux of [(3)H]cholesterol from HDL-[(3)H]CE to biliary bile acids was increased by overexpression of SCP2 or FABP1 in vivo and reduced in SCP2(-/-) mice. Increased flux of HDL-[(3)H]CE to biliary FC was noted with FABP1 overexpression and in SCP2(-/-) mice that have increased FABP1 expression. Lack of a significant decrease in the flux of HDL-[(3)H]CE to biliary FC or bile acids in FABP1(-/-) mice indicates the likely compensation of its function by an as yet unidentified mechanism. Taken together, these studies demonstrate that FABP1 and SCP2 facilitate the preferential movement of HDL-CEs to bile for final elimination. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.

Intracellular cholesterol transport proteins enhance hydrolysis of HDL-CEs and facilitate elimination of cholesterol into bile

PubMed Central

Wang, Jing; Bie, Jinghua; Ghosh, Shobha

2016-01-01

While HDL-associated unesterified or free cholesterol (FC) is thought to be rapidly secreted into the bile, the fate of HDL-associated cholesteryl esters (HDL-CEs) that represent >80% of HDL-cholesterol, is only beginning to be understood. In the present study, we examined the hypothesis that intracellular cholesterol transport proteins [sterol carrier protein 2 (SCP2) and fatty acid binding protein-1 (FABP1)] not only facilitate CE hydrolase-mediated hydrolysis of HDL-CEs, but also enhance elimination of cholesterol into bile. Adenovirus-mediated overexpression of FABP1 or SCP2 in primary hepatocytes significantly increased hydrolysis of HDL-[3H]CE, reduced resecretion of HDL-CE-derived FC as nascent HDL, and increased its secretion as bile acids. Consistently, the flux of [3H]cholesterol from HDL-[3H]CE to biliary bile acids was increased by overexpression of SCP2 or FABP1 in vivo and reduced in SCP2−/− mice. Increased flux of HDL-[3H]CE to biliary FC was noted with FABP1 overexpression and in SCP2−/− mice that have increased FABP1 expression. Lack of a significant decrease in the flux of HDL-[3H]CE to biliary FC or bile acids in FABP1−/− mice indicates the likely compensation of its function by an as yet unidentified mechanism. Taken together, these studies demonstrate that FABP1 and SCP2 facilitate the preferential movement of HDL-CEs to bile for final elimination. PMID:27381048

Structure-based drug design targeting the cell membrane receptor GPBAR1: exploiting the bile acid scaffold towards selective agonism

NASA Astrophysics Data System (ADS)

di Leva, Francesco Saverio; Festa, Carmen; Renga, Barbara; Sepe, Valentina; Novellino, Ettore; Fiorucci, Stefano; Zampella, Angela; Limongelli, Vittorio

2015-11-01

Bile acids can regulate nutrient metabolism through the activation of the cell membrane receptor GPBAR1 and the nuclear receptor FXR. Developing an exogenous control over these receptors represents an attractive strategy for the treatment of enterohepatic and metabolic disorders. A number of dual GPBAR1/FXR agonists are known, however their therapeutic use is limited by multiple unwanted effects due to activation of the diverse downstream signals controlled by the two receptors. On the other hand, designing selective GPBAR1 and FXR agonists is challenging since the two proteins share similar structural requisites for ligand binding. Here, taking advantage of our knowledge of the two targets, we have identified through a rational drug design study a series of amine lithocholic acid derivatives as selective GPBAR1 agonists. The presence of the 3α-NH2 group on the steroidal scaffold is responsible for the selectivity over FXR unveiling unprecedented structural insights into bile acid receptors activity modulation.

Bile Acids Down-Regulate Caveolin-1 in Esophageal Epithelial Cells through Sterol Responsive Element-Binding Protein

PubMed Central

Prade, Elke; Tobiasch, Moritz; Hitkova, Ivana; Schäffer, Isabell; Lian, Fan; Xing, Xiangbin; Tänzer, Marc; Rauser, Sandra; Walch, Axel; Feith, Marcus; Post, Stefan; Röcken, Christoph; Schmid, Roland M.; Ebert, Matthias P.A.

2012-01-01

Bile acids are synthesized from cholesterol and are major risk factors for Barrett adenocarcinoma (BAC) of the esophagus. Caveolin-1 (Cav1), a scaffold protein of membrane caveolae, is transcriptionally regulated by cholesterol via sterol-responsive element-binding protein-1 (SREBP1). Cav1 protects squamous epithelia by controlling cell growth and stabilizing cell junctions and matrix adhesion. Cav1 is frequently down-regulated in human cancers; however, the molecular mechanisms that lead to this event are unknown. We show that the basal layer of the nonneoplastic human esophageal squamous epithelium expressed Cav1 mainly at intercellular junctions. In contrast, Cav1 was lost in 95% of tissue specimens from BAC patients (n = 100). A strong cytoplasmic expression of Cav1 correlated with poor survival in a small subgroup (n = 5) of BAC patients, and stable expression of an oncogenic Cav1 variant (Cav1-P132L) in the human BAC cell line OE19 promoted proliferation. Cav1 was also detectable in immortalized human squamous epithelial, Barrett esophagus (CPC), and squamous cell carcinoma cells (OE21), but was low in BAC cell lines (OE19, OE33). Mechanistically, bile acids down-regulated Cav1 expression by inhibition of the proteolytic cleavage of 125-kDa pre-SREBP1 from the endoplasmic reticulum/Golgi apparatus and nuclear translocation of active 68-kDa SREBP1. This block in SREBP1's posttranslational processing impaired transcriptional activation of SREBP1 response elements in the proximal human Cav1 promoter. Cav1 was also down-regulated in esophagi from C57BL/6 mice on a diet enriched with 1% (wt/wt) chenodeoxycholic acid. Mice deficient for Cav1 or the nuclear bile acid receptor farnesoid X receptor showed hyperplasia and hyperkeratosis of the basal cell layer of esophageal epithelia, respectively. These data indicate that bile acid-mediated down-regulation of Cav1 marks early changes in the squamous epithelium, which may contribute to onset of Barrett esophagus metaplasia and progression to BAC. PMID:22474125

Synthesis and in vitro evaluation of potential sustained release prodrugs via targeting ASBT.

PubMed

Zheng, Xiaowan; Polli, James E

2010-08-30

The objective was to synthesize prodrugs of niacin and ketoprofen that target the human apical sodium-dependent bile acid transporter (ASBT) and potentially allow for prolonged drug release. Each drug was conjugated to the naturally occurring bile acid chenodeoxycholic acid (CDCA) using lysine as a linker. Their inhibitory binding and transport properties were evaluated in stably transfected ASBT-MDCK monolayers, and the kinetic parameters K(i), K(t), normJ(max), and P(p) were characterized. Enzymatic stability of the conjugates was evaluated in Caco-2 and liver homogenate. Both conjugates were potent inhibitors of ASBT. For the niacin prodrug, substrate kinetic parameter K(t) was 8.22microM and normJ(max) was 0.0917. In 4h, 69.4% and 26.9% of niacin was released from 1microM and 5microM of the conjugate in Caco-2 homogenate, respectively. For the ketoprofen prodrug, K(t) was 50.8microM and normJ(max) was 1.58. In 4h, 5.94% and 3.73% of ketoprofen was released from 1microM and 5microM of the conjugate in Caco-2 homogenate, and 24.5% and 12.2% of ketoprofen was released in liver homogenate, respectively. In vitro results showed that these bile acid conjugates are potential prolonged release prodrugs with binding affinity for ASBT. Copyright 2010 Elsevier B.V. All rights reserved.

Effect of common polymorphisms of the farnesoid X receptor and bile acid transporters on the pharmacokinetics of ursodeoxycholic acid.

PubMed

Hu, Miao; Fok, Benny S P; Wo, Siu-Kwan; Lee, Vincent H L; Zuo, Zhong; Tomlinson, Brian

2016-01-01

Ursodeoxycholic acid (UDCA), a natural, dihydroxy bile acid, promotes gallstone dissolution and has been attributed with several other beneficial effects. The farnesoid X receptor (FXR) may influence the pharmacokinetics of UDCA by modulating the expression of bile acid transporters. This exploratory study examined whether common functional polymorphisms in FXR and in bile acid transporter genes affect the pharmacokinetics of exogenous UDCA. Polymorphisms in genes for transporters involved in bile acid transport, solute carrier organic anion 1B1 (SLCO1B1) 388A>G and 521T>C, solute carrier 10A1 (SLC10A1) 800 C>T and ATP-binding cassette B11 (ABCB11) 1331T>C, and the FXR -1G>T polymorphism were genotyped in 26 male Chinese subjects who ingested single oral 500-mg doses of UDCA. Plasma concentrations of UDCA and its major conjugate metabolite glycoursodeoxycholic acid (GUDCA) were determined. The mean systemic exposure of UDCA was higher in the five subjects with one copy of the FXR -1G>T variant allele than in those homozygous for the wild-type allele (n = 21) (AUC0-24 h : 38.5 ± 28.2 vs. 20.9 ± 8.0 μg h/mL, P = 0.021), but this difference appeared mainly due to one outlier with the -1GT genotype and elevated baseline and post-treatment UDCA concentrations. After excluding the outlier, body weight was the only factor associated with plasma concentrations of UDCA and there were no significant associations with the other polymorphisms examined. None of the polymorphisms affected the pharmacokinetics of GUDCA. This study showed that the common polymorphisms in bile acid transporters had no significant effect on the pharmacokinetics of exogenous UDCA but an effect of the FXR polymorphism cannot be excluded. © 2015 Wiley Publishing Asia Pty Ltd.

The role of bile acids in nonalcoholic fatty liver disease and nonalcoholic steatohepatitis.

PubMed

Chow, Monica D; Lee, Yi-Horng; Guo, Grace L

2017-08-01

Nonalcoholic fatty liver disease is growing in prevalence worldwide. It is marked by the presence of macrosteatosis on liver histology but is often clinically asymptomatic. However, it can progress into nonalcoholic steatohepatitis which is a more severe form of liver disease characterized by inflammation and fibrosis. Further progression leads to cirrhosis, which predisposes patients to hepatocellular carcinoma or liver failure. The mechanism by which simple steatosis progresses to steatohepatitis is not entirely clear. However, multiple pathways have been proposed. A common link amongst many of these pathways is disruption of the homeostasis of bile acids. Other than aiding in the absorption of lipids and lipid-soluble vitamins, bile acids act as ligands. For example, they bind to farnesoid X receptor, which is critically involved in many of the pathways responsible for maintaining bile acid, glucose, and lipid homeostasis. Alterations to these pathways can lead to dysregulation of energy balance and increased inflammation and fibrosis. Repeated insults over time may be the key to development of steatohepatitis. For this reason, current drug therapies target aspects of these pathways to try to reduce and halt inflammation and fibrosis. This review will focus on the role of bile acids in these various pathways and how changes in these pathways may result in steatohepatitis. While there is no approved pharmaceutical treatment for either hepatic steatosis or steatohepatitis, this review will also touch upon the multitude of potential therapies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bile acid patterns in commercially available oxgall powders used for the evaluation of the bile tolerance ability of potential probiotics

PubMed Central

Hu, Peng-Li; Yuan, Ya-Hong; Yue, Tian-Li

2018-01-01

This study aimed to analyze the bile acid patterns in commercially available oxgall powders used for evaluation of the bile tolerance ability of probiotic bacteria. Qxgall powders purchased from Sigma-Aldrich, Oxoid and BD Difco were dissolved in distilled water, and analyzed. Conjugated bile acids were profiled by ion-pair high-performance liquid chromatography (HPLC), free bile acids were detected as their p-bromophenacyl ester derivatives using reversed-phase HPLC after extraction with acetic ether, and total bile acids were analyzed by enzymatic-colorimetric assay. The results showed that 9 individual bile acids (i.e., taurocholic acid, glycocholic acid, taurodeoxycholic acid, glycodeoxycholic acid, taurochenodeoxycholic acid, glycochenodeoxycholic acid, cholic acid, chenodeoxycholic acid, deoxycholic acid) were present in each of the oxgall powders tested. The content of total bile acid among the three oxgall powders was similar; however, the relative contents of the individual bile acids among these oxgall powders were significantly different (P < 0.001). The oxgall powder from Sigma-Aldrich was closer to human bile in the ratios of glycine-conjugated bile acids to taurine-conjugated bile acids, dihydroxy bile acids to trihydroxy bile acids, and free bile acids to conjugated bile acids than the other powders were. It was concluded that the oxgall powder from Sigma-Aldrich should be used instead of those from Oxoid and BD Difco to evaluate the bile tolerance ability of probiotic bacteria as human bile model. PMID:29494656

Bile Acid Metabolism in Liver Pathobiology

PubMed Central

Chiang, John Y. L.; Ferrell, Jessica M.

2018-01-01

Bile acids facilitate intestinal nutrient absorption and biliary cholesterol secretion to maintain bile acid homeostasis, which is essential for protecting liver and other tissues and cells from cholesterol and bile acid toxicity. Bile acid metabolism is tightly regulated by bile acid synthesis in the liver and bile acid biotransformation in the intestine. Bile acids are endogenous ligands that activate a complex network of nuclear receptor farnesoid X receptor and membrane G protein-coupled bile acid receptor-1 to regulate hepatic lipid and glucose metabolic homeostasis and energy metabolism. The gut-to-liver axis plays a critical role in the regulation of enterohepatic circulation of bile acids, bile acid pool size, and bile acid composition. Bile acids control gut bacteria overgrowth, and gut bacteria metabolize bile acids to regulate host metabolism. Alteration of bile acid metabolism by high-fat diets, sleep disruption, alcohol, and drugs reshapes gut microbiome and causes dysbiosis, obesity, and metabolic disorders. Gender differences in bile acid metabolism, FXR signaling, and gut microbiota have been linked to higher prevalence of fatty liver disease and hepatocellular carcinoma in males. Alteration of bile acid homeostasis contributes to cholestatic liver diseases, inflammatory diseases in the digestive system, obesity, and diabetes. Bile acid-activated receptors are potential therapeutic targets for developing drugs to treat metabolic disorders. PMID:29325602

Characterizing Factors Associated With Differences in FGF19 Blood Levels and Synthesis in Patients With Primary Bile Acid Diarrhea.

PubMed

Johnston, Ian M; Nolan, Jonathan D; Pattni, Sanjeev S; Appleby, Richard N; Zhang, Justine H; Kennie, Sarah L; Madhan, Gaganjit K; Jameie-Oskooei, Sina; Pathmasrirengam, Shivani; Lin, Jeremy; Hong, Albert; Dixon, Peter H; Williamson, Catherine; Walters, Julian R F

2016-03-01

Chronic diarrhea caused by primary bile acid diarrhea (PBAD) is a common condition. We have previously shown PBAD is associated with low fasting serum levels of the ileal hormone, fibroblast growth factor 19 (FGF19). FGF19 is a negative regulator of hepatic bile acid synthesis and is stimulated by farnesoid X receptor agonists, which produce symptomatic improvement in PBAD. We aimed to assess possible causes for low serum FGF19 in patients with PBAD. Patients with PBAD, defined by reduced (75)Se-labelled homocholic acid taurine (SeHCAT) retention, and idiopathic diarrhea controls had measurements of fasting lipids and fasting/post-prandial FGF19 serum profiles. Specific functional variants in candidate genes were investigated in exploratory studies. In further groups, basal and bile acid-stimulated transcript expression was determined in ileal biopsies and explant cultures by quantitative PCR. FGF19 profiles in PBAD patients included low fasting and meal-stimulated responses, which were both strongly correlated with SeHCAT. A subgroup of 30% of PBAD patients had fasting hypertriglyceridemia and higher FGF19. No clear significant differences were found for any genetic variant but there were borderline associations with FGFR4 and KLB. SeHCAT retention significantly correlated with the basal ileal transcript expression of FGF19 (rs=0.59, P=0.03) and apical sodium-dependent bile acid transporter (ASBT) (rs=0.49, P=0.04), and also with the degree of stimulation by chenodeoxycholic acid at 6 h for transcripts of FGF19 (median 184-fold, rs=0.50, P=0.02) and ileal bile acid binding protein (IBABP) (median 2.2-fold, rs=0.47, P=0.04). Median stimulation of FGF19 was lower in patients with SeHCAT retention <10% (P=0.01). These studies demonstrate a complex, multifactorial etiology of PBAD, including impairments in ileal FGF19 expression and responsiveness.

Coupling ligand recognition to protein folding in an engineered variant of rabbit ileal lipid binding protein.

PubMed

Kouvatsos, Nikolaos; Meldrum, Jill K; Searle, Mark S; Thomas, Neil R

2006-11-28

We have engineered a variant of the beta-clam shell protein ILBP which lacks the alpha-helical motif that caps the central binding cavity; the mutant protein is sufficiently destabilised that it is unfolded under physiological conditions, however, it unexpectedly binds its natural bile acid substrates with high affinity forming a native-like beta-sheet rich structure and demonstrating strong thermodynamic coupling between ligand binding and protein folding.

Decreased glucagon responsiveness by bile acids: a role for protein kinase Calpha and glucagon receptor phosphorylation.

PubMed

Ikegami, Tadashi; Krilov, Lada; Meng, Jianping; Patel, Bhumika; Chapin-Kennedy, Kelli; Bouscarel, Bernard

2006-11-01

Dihydroxy bile acids like chenodeoxycholic acid (CDCA) induce heterologous glucagon receptor desensitization. We previously demonstrated that protein kinase C (PKC) was activated by certain bile acids and mediated the CDCA-induced decrease in glucagon responsiveness. The aim of the present study was to explore the role of PKC in the phosphorylation and desensitization of the glucagon receptor by CDCA. Desensitization was evaluated by measuring adenylyl cyclase activity. Receptor phosphorylation was assayed by metabolic labeling with [gamma-(32)P] ATP. Protein kinase C (PKC) translocation and activation was visualized by fluorescence microscopy. CDCA decreased cAMP production induced by glucagon in a dose-dependent manner without affecting cAMP synthesis through stimulation of either stimulatory GTP-binding protein (Gs) by NaF or adenylyl cyclase by forskolin. The CDCA-induced inhibition of adenylyl cyclase activity was potentiated by the phosphatase inhibitor, okadaic acid. The desensitizing effect of CDCA was bile acid-specific and was significantly reduced in the presence of PKC inhibitors and after PKC down-regulation by phorbol 12-myristate 13-acetate. CDCA increased glucagon receptor phosphorylation more than 3-fold at concentrations as low as 25 mum. Furthermore, CDCA significantly stimulated human recombinant PKCalpha autophosphorylation in vitro, as well as PKCalpha translocation to the plasma membrane and phosphorylation in vivo at concentrations as low as 25 mum. CDCA also stimulated PKCdelta translocation to the perinuclear region. Activated PKCalpha, PKCzeta, and to a lesser extent, PKCdelta, phosphorylated the glucagon receptor in vitro. This study demonstrates that certain bile acids, such as CDCA, stimulate phosphorylation and heterologous desensitization of the glucagon receptor, involving at least PKCalpha activation.

Differentiation of various traditional Chinese medicines derived from animal bile and gallstone: simultaneous determination of bile acids by liquid chromatography coupled with triple quadrupole mass spectrometry.

PubMed

Qiao, Xue; Ye, Min; Pan, De-lin; Miao, Wen-juan; Xiang, Cheng; Han, Jian; Guo, De-an

2011-01-07

Animal biles and gallstones are popularly used in traditional Chinese medicines, and bile acids are their major bioactive constituents. Some of these medicines, like cow-bezoar, are very expensive, and may be adulterated or even replaced by less expensive but similar species. Due to poor ultraviolet absorbance and structural similarity of bile acids, effective technology for species differentiation and quality control of bile-based Chinese medicines is still lacking. In this study, a rapid and reliable method was established for the simultaneous qualitative and quantitative analysis of 18 bile acids, including 6 free steroids (cholic acid, chenodeoxycholic acid, deoxycholic acid, lithocholic acid, hyodeoxycholic acid, and ursodeoxycholic acid) and their corresponding glycine conjugates and taurine conjugates, by using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). This method was used to analyze six bile-based Chinese medicines: bear bile, cattle bile, pig bile, snake bile, cow-bezoar, and artificial cow-bezoar. Samples were separated on an Atlantis dC₁₈ column and were eluted with methanol-acetonitrile-water containing ammonium acetate. The mass spectrometer was monitored in the negative electrospray ionization mode. Total ion currents of the samples were compared for species differentiation, and the contents of bile acids were determined by monitoring specific ion pairs in a selected reaction monitoring program. All 18 bile acids showed good linearity (r² > 0.993) in a wide dynamic range of up to 2000-fold, using dehydrocholic acid as the internal standard. Different animal biles could be explicitly distinguished by their major characteristic bile acids: tauroursodeoxycholic acid and taurochenodeoxycholic acid for bear bile, glycocholic acid, cholic acid and taurocholic acid for cattle bile, glycohyodeoxycholic acid and glycochenodeoxycholic acid for pig bile, and taurocholic acid for snake bile. Furthermore, cattle bile, cow-bezoar, and artificial cow-bezoar could be differentiated by the existence of hyodeoxycholic acid and the ratio of cholic acid to deoxycholic acid. This study provided bile acid profiles of bile-based Chinese medicines for the first time, which could be used for their quality control. Copyright © 2010 Elsevier B.V. All rights reserved.

The human fatty acid-binding protein family: Evolutionary divergences and functions

PubMed Central

2011-01-01

Fatty acid-binding proteins (FABPs) are members of the intracellular lipid-binding protein (iLBP) family and are involved in reversibly binding intracellular hydrophobic ligands and trafficking them throughout cellular compartments, including the peroxisomes, mitochondria, endoplasmic reticulum and nucleus. FABPs are small, structurally conserved cytosolic proteins consisting of a water-filled, interior-binding pocket surrounded by ten anti-parallel beta sheets, forming a beta barrel. At the superior surface, two alpha-helices cap the pocket and are thought to regulate binding. FABPs have broad specificity, including the ability to bind long-chain (C16-C20) fatty acids, eicosanoids, bile salts and peroxisome proliferators. FABPs demonstrate strong evolutionary conservation and are present in a spectrum of species including Drosophila melanogaster, Caenorhabditis elegans, mouse and human. The human genome consists of nine putatively functional protein-coding FABP genes. The most recently identified family member, FABP12, has been less studied. PMID:21504868

A Cytosolic Amphiphilic α-Helix Controls the Activity of the Bile Acid-sensitive Ion Channel (BASIC)*

PubMed Central

Schmidt, Axel; Löhrer, Daniel; Alsop, Richard J.; Lenzig, Pia; Oslender-Bujotzek, Adrienne; Wirtz, Monika; Rheinstädter, Maikel C.; Gründer, Stefan; Wiemuth, Dominik

2016-01-01

The bile acid-sensitive ion channel (BASIC) is a member of the degenerin/epithelial Na+ channel (Deg/ENaC) family of ion channels. It is mainly found in bile duct epithelial cells, the intestinal tract, and the cerebellum and is activated by alterations of its membrane environment. Bile acids, one class of putative physiological activators, exert their effect by changing membrane properties, leading to an opening of the channel. The physiological function of BASIC, however, is unknown. Deg/ENaC channels are characterized by a trimeric subunit composition. Each subunit is composed of two transmembrane segments, which are linked by a large extracellular domain. The termini of the channels protrude into the cytosol. Many Deg/ENaC channels contain regulatory domains and sequence motifs within their cytosolic domains. In this study, we show that BASIC contains an amphiphilic α-helical structure within its N-terminal domain. This α-helix binds to the cytosolic face of the plasma membrane and stabilizes a closed state. Truncation of this domain renders the channel hyperactive. Collectively, we identify a cytoplasmic domain, unique to BASIC, that controls channel activity via membrane interaction. PMID:27679529

A Cytosolic Amphiphilic α-Helix Controls the Activity of the Bile Acid-sensitive Ion Channel (BASIC).

PubMed

Schmidt, Axel; Löhrer, Daniel; Alsop, Richard J; Lenzig, Pia; Oslender-Bujotzek, Adrienne; Wirtz, Monika; Rheinstädter, Maikel C; Gründer, Stefan; Wiemuth, Dominik

2016-11-18

The bile acid-sensitive ion channel (BASIC) is a member of the degenerin/epithelial Na + channel (Deg/ENaC) family of ion channels. It is mainly found in bile duct epithelial cells, the intestinal tract, and the cerebellum and is activated by alterations of its membrane environment. Bile acids, one class of putative physiological activators, exert their effect by changing membrane properties, leading to an opening of the channel. The physiological function of BASIC, however, is unknown. Deg/ENaC channels are characterized by a trimeric subunit composition. Each subunit is composed of two transmembrane segments, which are linked by a large extracellular domain. The termini of the channels protrude into the cytosol. Many Deg/ENaC channels contain regulatory domains and sequence motifs within their cytosolic domains. In this study, we show that BASIC contains an amphiphilic α-helical structure within its N-terminal domain. This α-helix binds to the cytosolic face of the plasma membrane and stabilizes a closed state. Truncation of this domain renders the channel hyperactive. Collectively, we identify a cytoplasmic domain, unique to BASIC, that controls channel activity via membrane interaction. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Lipid flopping in the liver.

PubMed

Linton, Kenneth J

2015-10-01

Bile is synthesized in the liver and is essential for the emulsification of dietary lipids and lipid-soluble vitamins. It is a complex mixture of amphiphilic bile acids (BAs; which act as detergent molecules), the membrane phospholipid phosphatidylcholine (PC), cholesterol and a variety of endogenous metabolites and waste products. Over the last 20 years, the combined effort of clinicians, geneticists, physiologists and biochemists has shown that each of these bile components is transported across the canalicular membrane of the hepatocyte by its own specific ATP-binding cassette (ABC) transporter. The bile salt export pump (BSEP) ABCB11 transports the BAs and drives bile flow from the liver, but it is now clear that two lipid transporters, ABCB4 (which flops PC into the bile) and the P-type ATPase ATP8B1/CDC50 (which flips a different phospholipid in the opposite direction) play equally critical roles that protect the biliary tree from the detergent activity of the bile acids. Understanding the interdependency of these lipid floppases and flippases has allowed the development of an assay to measure ABCB4 function. ABCB4 harbours numerous mis-sense mutations which probably reflects the spectrum of liver disease rooted in ABCB4 aetiology. Characterization of the effect of these mutations at the protein level opens the possibility for the development of personalized prognosis and treatment. © 2015 Authors; published by Portland Press Limited.

New insights into bile acid malabsorption.

PubMed

Johnston, Ian; Nolan, Jonathan; Pattni, Sanjeev S; Walters, Julian R F

2011-10-01

Bile acid malabsorption occurs when there is impaired absorption of bile acids in the terminal ileum, so interrupting the normal enterohepatic circulation. The excess bile acids in the colon cause diarrhea, and treatment with bile acid sequestrants is beneficial. The condition can be diagnosed with difficulty by measuring fecal bile acids, or more easily by retention of selenohomocholyltaurine (SeHCAT), where this is available. Chronic diarrhea caused by primary bile acid diarrhea appears to be common, but is under-recognized where SeHCAT testing is not performed. Measuring excessive bile acid synthesis with 7α-hydroxy-4-cholesten-3-one may be an alternative means of diagnosis. It appears that there is no absorption defect in primary bile acid diarrhea but, instead, an overproduction of bile acids. Fibroblast growth factor 19 (FGF19) inhibits hepatic bile acid synthesis. Defective production of FGF19 from the ileum may be the cause of primary bile acid diarrhea.

Inhibition of Intestinal Bile Acid Transporter Slc10a2 Improves Triglyceride Metabolism and Normalizes Elevated Plasma Glucose Levels in Mice

PubMed Central

Snaith, Michael; Lindmark, Helena; Lundberg, Johanna; Östlund-Lindqvist, Ann-Margret; Angelin, Bo; Rudling, Mats

2012-01-01

Interruption of the enterohepatic circulation of bile acids increases cholesterol catabolism, thereby stimulating hepatic cholesterol synthesis from acetate. We hypothesized that such treatment should lower the hepatic acetate pool which may alter triglyceride and glucose metabolism. We explored this using mice deficient of the ileal sodium-dependent BA transporter (Slc10a2) and ob/ob mice treated with a specific inhibitor of Slc10a2. Plasma TG levels were reduced in Slc10a2-deficient mice, and when challenged with a sucrose-rich diet, they displayed a reduced response in hepatic TG production as observed from the mRNA levels of several key enzymes in fatty acid synthesis. This effect was paralleled by a diminished induction of mature sterol regulatory element-binding protein 1c (Srebp1c). Unexpectedly, the SR-diet induced intestinal fibroblast growth factor (FGF) 15 mRNA and normalized bile acid synthesis in Slc10a2−/− mice. Pharmacologic inhibition of Slc10a2 in diabetic ob/ob mice reduced serum glucose, insulin and TGs, as well as hepatic mRNA levels of Srebp1c and its target genes. These responses are contrary to those reported following treatment of mice with a bile acid binding resin. Moreover, when key metabolic signal transduction pathways in the liver were investigated, those of Mek1/2 - Erk1/2 and Akt were blunted after treatment of ob/ob mice with the Slc10a2 inhibitor. It is concluded that abrogation of Slc10a2 reduces hepatic Srebp1c activity and serum TGs, and in the diabetic ob/ob model it also reduces glucose and insulin levels. Hence, targeting of Slc10a2 may be a promising strategy to treat hypertriglyceridemia and diabetes. PMID:22662222

Bile acid metabolism and signaling in cholestasis, inflammation and cancer

PubMed Central

Apte, Udayan

2015-01-01

Bile acids are synthesized from cholesterol in the liver. Some cytochrome P450 (CYP) enzymes play key roles in bile acid synthesis. Bile acids are physiological detergent molecules, so are highly cytotoxic. They undergo enterohepatic circulation and play important roles in generating bile flow and facilitating biliary secretion of endogenous metabolites and xenobiotics and intestinal absorption of dietary fats and lipid soluble vitamins. Bile acid synthesis, transport and pool size are therefore tightly regulated under physiological conditions. In cholestasis, impaired bile flow leads to accumulation of bile acids in the liver, causing hepatocyte and biliary injury and inflammation. Chronic cholestasis is associated with fibrosis, cirrhosis and eventually liver failure. Chronic cholestasis also increases the risk of developing hepatocellular or cholangiocellular carcinomas. Extensive research in the last two decades has shown that bile acids act as signaling molecules that regulate various cellular processes. The bile acid-activated nuclear receptors are ligand-activated transcriptional factors that play critical roles in the regulation of bile acid, drug and xenobiotic metabolism. In cholestasis, these bile acid-activated receptors regulate a network of genes involved in bile acid synthesis, conjugation, transport and metabolism to alleviate bile acid-induced inflammation and injury. Additionally, bile acids are known to regulate cell growth and proliferation, and altered bile acid levels in diseased conditions have been implicated in liver injury/regeneration and tumorigenesis. We will cover the mechanisms that regulate bile acid homeostasis and detoxification during cholestasis, and the roles of bile acids in the initiation and regulation of hepatic inflammation, regeneration and carcinogenesis. PMID:26233910

Analyses of bile from gallbladders of Arius platystomus, Arius tenuispinis, Pomadasys commersonni and Kishinoella tonggol.

PubMed

Hassan, Amir; Ahmed, Mansoor; Rasheed, Munawwer; Mansoor, Najia; Khan, Rafeeq Alam; Kamal, Mustafa; Rashid, Mohammad Abdur

2015-07-01

Bile from gallbladders of Arius platystomus (Singhara), Arius tenuispinis (Khagga), Pomadasys commersonni (Holoola) and Kishinoella tonggol (Dawan) were derivatised and analysed by GC-MS for identification of bile acids and bile alcohols. Cholic acid and Chenodeoxycholic acid were found as major bile acids in Arius platystomus, Arius tenuispinis and Pomadasys commersonni. Other bile acids identified in Arius platystomus were allochenodeoxycholic acid, allodeoxycholic acid, 3α,7α,12α-trihydroxy-24-methyl-5β-cholestane-26-oic acid, and 3α,7α,12α, 24-tetrahydroxy-5α-cholestane-26-oic acid. Cholesterol was found as major bile alcohol in Arius platystomus, Arius tenuispinis and Pomadasys commersonni. Cholic acid was the major bile acid identified in the bile of Kishinoella tonggol while other bile acids included 3α,7α,12α-tridydroxy-5α-cholestanoic acid and 3α,7α,12α-tridydroxy-5β-cholestanoic acid. Bile alcohol 5β-cyprinol was present in significant amounts with 5β-cholestane-3α,7α,12α,24-tetrol being the other contributors in the bile of Kishinoella tonggol.

Interactions between gut bacteria and bile in health and disease.

PubMed

Long, Sarah L; Gahan, Cormac G M; Joyce, Susan A

2017-08-01

Bile acids are synthesized from cholesterol in the liver and released into the intestine to aid the digestion of dietary lipids. The host enzymes that contribute to bile acid synthesis in the liver and the regulatory pathways that influence the composition of the total bile acid pool in the host have been well established. In addition, the gut microbiota provides unique contributions to the diversity of bile acids in the bile acid pool. Gut microbial enzymes contribute significantly to bile acid metabolism through deconjugation and dehydroxylation reactions to generate unconjugated bile acids and secondary bile acids. These microbial enzymes (which include bile salt hydrolase (BSH) and bile acid-inducible (BAI) enzymes) are essential for bile acid homeostasis in the host and represent a vital contribution of the gut microbiome to host health. Perturbation of the gut microbiota in disease states may therefore significantly influence bile acid signatures in the host, especially in the context of gastrointestinal or systemic disease. Given that bile acids are ligands for host cell receptors (including the FXR, TGR5 and Vitamin D Receptor) alterations to microbial enzymes and associated changes to bile acid signatures have significant consequences for the host. In this review we examine the contribution of microbial enzymes to the process of bile acid metabolism in the host and discuss the implications for microbe-host signalling in the context of C. difficile infection, inflammatory bowel disease and other disease states. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Fiber in the diet--certainties and speculation].

PubMed

Peters, P; Peters, K M

1988-06-01

This report defines dietary fibre and summarizes its effects on dental, gastrointestinal and metabolic diseases. A higher intake of dietary fibre is important in prophylaxis of caries, paradentosis, constipation, diverticulosis, colon cancer, diabetes and hypercholesteraemia. An ideal preparation must have the following abilities: It should be coarse, hard and swallowable and without cariogenic sugars in order to prevent dental diseases. It should be a mixture of several kinds of fibre getting water binding capacity and bile acid binding capacity. Mechanical crushing and heatening of fibre are to be avoided. The preparation should not contain phytic acid.

Increased binding of LDL and VLDL to apo B,E receptors of hepatic plasma membrane of rats treated with Fibernat.

PubMed

Venkatesan, Nandini; Devaraj, S Niranjali; Devaraj, H

2003-10-01

Research has focussed on the hypocholesterolemic effects of certain types of dietary fiber such as enhancing conversion of hepatic cholesterol to bile acids or increase in catabolism of low density lipoprotein (LDL) via the apo B,E receptor. The effect of oral administration of a unique fibre cocktail of fenugreek seed powder, guar gum and wheat bran (Fibernat) and its varied effects on some aspects of lipid metabolism and cholesterol homeostasis in rats were examined. Rats were administered Fibernat along with the atherogenic diet containing 1.5 % cholesterol and 0.1 % cholic acid. Amounts of hepatic lipids, hepatic and fecal bile acids and activity of hepatic triglyceride lipase (HTGL) were determined. Transmission electron microscopic examination of the liver tissue and extent of uptake of (125)I-LDL and (125)I-VLDL by the hepatic apo B,E receptor was carried out. Food intake and body weight gain were similar between the 3 different dietary groups. Fibernat intake significantly increased apo B,E receptor expression in rat liver as reflected by an increase in the maximum binding capacity (B(max)) of the apo B,E receptor to (125)I-LDL and (125)I-VLDL. The activity of HTGL was increased by approximately 1.5-fold in Fibernat-fed rats as compared to those fed the atherogenic diet alone. A marked hypocholesterolemic effect was observed. Cholesterol homeostasis was achieved in Fibernat-fed rats. Two possible mechanisms are postulated to be responsible for the observed hypocholesterolemic effect a) an increase in conversion of cholesterol to bile acids and b) possibly by intra-luminal binding which resulted in increased fecal excretion of bile acids and neutral sterols. The resulting reduction in cholesterol content of liver cells coupled with upregulation of hepatic apo B,E receptors and increased clearance of circulating atherogenic lipoproteins-LDL and very low density lipoprotein (LDL and VLDL)-is the main mechanism involved in the hypocholesterolemic effect of Fibernat. The results suggest that Fibernat's effect on plasma LDL concentration is also possibly mediated by increased receptor-mediated catabolism of VLDL. Thus, Fibernat therapy is an effective adjunct to diet therapy and might find potential use in the therapy of hyperlipidemic subjects.

Bile resistance in Lactococcus lactis strains varies with cellular fatty acid composition: analysis by using different growth media.

PubMed

Kimoto-Nira, Hiromi; Kobayashi, Miho; Nomura, Masaru; Sasaki, Keisuke; Suzuki, Chise

2009-05-31

Bile resistance is one of the basic characteristics of probiotic bacteria. The aim of this study was to investigate the characteristics of bile resistance in lactococci by studying the relationship between bile resistance and cellular fatty acid composition in lactococcci grown on different media. We determined the bile resistance of 14 strains in lactose-free M17 medium supplemented with either glucose only (GM17) or lactose only (LM17). Gas chromatographic analyses of free lipids extracted from the tested strains were used for determining their fatty acid composition. A correlation analysis of all strains grown in both media revealed significant positive correlations between bile resistance and relative contents of hexadecanoic acid and octadecenoic acid, and negative correlations between bile resistance and relative contents of hexadecenoic acid and C-19 cyclopropane fatty acid. It is also a fact that the fatty acids associated with bile resistance depended on species, strain, and/or growth medium. In L. lactis subsp. cremoris strains grown in GM17 medium, the bile-resistant strains had significantly more octadecenoic acid than the bile-sensitive strains. In LM17 medium, bile-resistant strains had significantly more octadecenoic acid and significantly less C-19 cyclopropane fatty acid than the bile-sensitive strains. In L. lactis subsp. lactis strains, bile resistances of some of the tested strains were altered by growth medium. Some strains were resistant to bile in GM17 medium but sensitive to bile in LM17 medium. Some strains were resistant in both media tested. The strains grown in GM17 medium had significantly more hexadecanoic acid and octadecenoic acid, and significantly less tetradecanoic acid, octadecadienoic acid and C-19 cyclopropane fatty acid than the strains grown in LM17 medium. In conclusion, the fatty acid compositions of the bile-resistant lactococci differed from those of the bile-sensitive ones. More importantly, our data suggest that altering their fatty acid composition (i.e. increased hexadecanoic acid and octadecenoic acid and decreased hexadecenoic acid and C-19 cyclopropane fatty acid) by changing growth conditions may be a useful way to enhance their bile resistance in lactococci.

[Analysis on replacement of traditional Chinese medicine bear bile with bile acids based on drug properties].

PubMed

Yuan, Bin; Ren, Ying-Long; Ma, Li; Gu, Hao; Wang, Yun; Qiao, Yan-Jiang

2014-02-01

To discuss the rationality of the clinical replacement of traditional Chinese medicine (TCM) bear bile with bile acid constituents, and analyze the difference between these constituents and bear bile in drug properties. Summarizing the drug properties of bear bile by reference to medical literatures for drug properties of TCM bear bile and Science of Traditional Chinese Medicine (China Press of Traditional Chinese Medicine, 2007). Analyzing and summarizing the pharmacological effects of main bile acid constituents according to relevant literatures for studies on pharmacological effects of main bile acid constituents in CNKI database. Predicating the drug properties of these bile acid constituents by using the drug property predication model established by the study group according the pharmacological effects of main bile acid constituents in the paper, and compare the prediction results with the drug properties of bear bile. Bile acid constituents in bear bile were mostly cold in property, bitter in taste, and the combination of their drug properties could reflect the combined drug properties of bear bile. All of these bile acid constituents in bear bile could show part of effects of bear bile. Attention shall be given to regulate the medication scheme in clinical application according to actual conditions.

The bile acid composition of crane gallbladder bile

USGS Publications Warehouse

Serafin, J.A.

1983-01-01

1. The biliary bile acids of the whooping crane (Grus americana) and the Florida sandhill crane (G. canadensis pratensis) have been examined.2. Cholic acid (CA), chenodeoxycholic acid (CDOCA) and lithocholic acid were found in bile from both species of these North American cranes.3. CDOCA and CA were the primary bile acids in both species, together constituting 70% or more of the bile acids by weight.4. The primary bile acids of cranes appear to be the same as those that have been identified in other avian species.

Normal or increased bile acid uptake in isolated mucosa from patients with bile acid malabsorption.

PubMed

Bajor, Antal; Kilander, Anders; Fae, Anita; Gälman, Cecilia; Jonsson, Olof; Ohman, Lena; Rudling, Mats; Sjövall, Henrik; Stotzer, Per-Ove; Ung, Kjell-Arne

2006-04-01

Bile acid malabsorption as reflected by an abnormal Se-labelled homocholic acid-taurine (SeHCAT) test is associated with diarrhoea, but the mechanisms and cause-and-effect relations are unclear. Primarily, to determine whether there is a reduced active bile acid uptake in the terminal ileum in patients with bile acid malabsorption. Secondarily, to study the linkage between bile acid malabsorption and hepatic bile acid synthesis. Ileal biopsies were taken from patients with diarrhoea and from controls with normal bowel habits. Maximal active bile acid uptake was assessed in ileal biopsies using a previously validated technique based on uptake of C-labelled taurocholate. To monitor the hepatic synthesis, 7alpha-hydroxy-4-cholesten-3-one, a bile acid precursor, was assayed in blood. The SeHCAT-retention test was used to diagnose bile acid malabsorption. The taurocholate uptake in specimens from diarrhoea patients was higher compared with the controls [median, 7.7 (n=53) vs 6.1 micromol/g per min (n=17)] (P<0.01) but no difference was seen between those with bile acid malabsorption (n=18) versus diarrhoea with a normal SeHCAT test (n=23). The SeHCAT values and 7alpha-hydroxy-4-cholesten-3-one were inversely correlated. The data do not support bile acid malabsorption being due to a reduced active bile acid uptake capacity in the terminal ileum.

Review: Management of postprandial diarrhea syndrome.

PubMed

Money, Mary E; Camilleri, Michael

2012-06-01

Unexpected, urgent, sometimes painful bowel movements after eating are common complaints among adults. Without a clear etiology, if pain is present and resolves with the movements, this is usually labeled "irritable bowel syndrome-diarrhea" based solely on symptoms. If this symptom-based approach is applied exclusively, it may lead physicians not to consider treatable conditions: celiac disease, or maldigestion due to bile acid malabsorption, pancreatic exocrine insufficiency, or an a-glucosidase (sucrase, glucoamylase, maltase, or isomaltase) deficiency. These conditions can be misdiagnosed as irritable bowel syndrome-diarrhea (or functional diarrhea, if pain is not present). Limited testing is currently available to confirm these conditions (antibody screens for celiac disease; fecal fat as a surrogate marker for pancreatic function). Therefore, empirical treatment with alpha amylase, pancreatic enzymes, or a bile acid-binding agent may simultaneously treat these patients and serve as a surrogate diagnostic test. This review will summarize the current evidence for bile acid malabsorption, and deficiencies of pancreatic enzymes or a-glucosidases as potential causes for postprandial diarrhea, and provide an algorithm for treatment options. Copyright © 2012 Elsevier Inc. All rights reserved.

Therapeutic targeting of bile acids

PubMed Central

Gores, Gregory J.

2015-01-01

The first objectives of this article are to review the structure, chemistry, and physiology of bile acids and the types of bile acid malabsorption observed in clinical practice. The second major theme addresses the classical or known properties of bile acids, such as the role of bile acid sequestration in the treatment of hyperlipidemia; the use of ursodeoxycholic acid in therapeutics, from traditional oriental medicine to being, until recently, the drug of choice in cholestatic liver diseases; and the potential for normalizing diverse bowel dysfunctions in irritable bowel syndrome, either by sequestering intraluminal bile acids for diarrhea or by delivering more bile acids to the colon to relieve constipation. The final objective addresses novel concepts and therapeutic opportunities such as the interaction of bile acids and the microbiome to control colonic infections, as in Clostridium difficile-associated colitis, and bile acid targeting of the farnesoid X receptor and G protein-coupled bile acid receptor 1 with consequent effects on energy expenditure, fat metabolism, and glycemic control. PMID:26138466

Mechanisms of triglyceride metabolism in patients with bile acid diarrhea

PubMed Central

Sagar, Nidhi Midhu; McFarlane, Michael; Nwokolo, Chuka; Bardhan, Karna Dev; Arasaradnam, Ramesh Pulendran

2016-01-01

Bile acids (BAs) are essential for the absorption of lipids. BA synthesis is inhibited through intestinal farnesoid X receptor (FXR) activity. BA sequestration is known to influence BA metabolism and control serum lipid concentrations. Animal data has demonstrated a regulatory role for the FXR in triglyceride metabolism. FXR inhibits hepatic lipogenesis by inhibiting the expression of sterol regulatory element binding protein 1c via small heterodimer primer activity. Conversely, FXR promotes free fatty acids oxidation by inducing the expression of peroxisome proliferator-activated receptor α. FXR can reduce the expression of microsomal triglyceride transfer protein, which regulates the assembly of very low-density lipoproteins (VLDL). FXR activation in turn promotes the clearance of circulating triglycerides by inducing apolipoprotein C-II, very low-density lipoproteins receptor (VLDL-R) and the expression of Syndecan-1 together with the repression of apolipoprotein C-III, which increases lipoprotein lipase activity. There is currently minimal clinical data on triglyceride metabolism in patients with bile acid diarrhoea (BAD). Emerging data suggests that a third of patients with BAD have hypertriglyceridemia. Further research is required to establish the risk of hypertriglyceridaemia in patients with BAD and elicit the mechanisms behind this, allowing for targeted treatment. PMID:27570415

Plasma lathosterol as a screening test for bile acid malabsorption due to ileal resection: correlation with 75SeHCAT test and faecal bile acid excretion.

PubMed

Färkkilä, M A; Kairemo, K J; Taavitsainen, M J; Strandberg, T A; Miettinen, T A

1996-04-01

1. Plasma lathosterol concentration, known to reflect cholesterol and bile acid synthesis, was evaluated as a screening test for bile acid malabsorption, comparing it with faecal bile acid measurements, SeHCAT test and Schilling test in 22 subjects of whom six were healthy controls and 16 had Crohn's disease with ileal resections of varying length. 2. Plasma lathosterols and other non-cholesterol sterols were determined by GLC. Faecal bile acids were measured by GLC, and SeHCAT retention times by gamma camera. The study subjects were divided into two groups according to the degree of bile acid malabsorption: controls (faecal bile acids < 10 mg day-1 kg-1, n = 9) and bile acid malabsorption (faecal bile acids > 10 mg day-1 kg-1, n = 13). 3. Faecal bile acid excretion was 5.9 +/- 1.0 mg day-1 kg-1 in control subjects and 45.7 +/- 6.1 mg day-1 kg-1 in the bile acid malabsorption group. The biological half-life of 75SeHCAT (T1/2) was 95.6 +/- 16.3 h and 14.1 +/- 4.1 h, respectively. Plasma lathosterol levels were significantly elevated in patients with bile acid malabsorption (742 +/- 84 micrograms/ml compared with 400 +/- 59 micrograms/ml in control subjects) and correlated closely with faecal bile acid levels (r = 0.779, P < 0.001), with 75SeHCAT T1/2 (r = -0.524, P < 0.05) and with Schilling test (r = -0.591, P < 0.05). Significant correlations were also obtained for delta 8-cholestenol with faecal bile acids (r = 0.784, P < 0.001) and 75SeHCAT (r = -0.505, P < 0.05). The biological half-life of SeHCAT correlated with faecal bile acid excretion (r = -0.702, P < 0.001). Using mean+2 SD of lathosterol (In micrograms/ml cholesterol) as a cut-off value and 10 mg day-1 kg-1 as the upper limit for faecal bile acid excretion, the test gives 100% sensitivity and 82% specificity for plasma lathosterol determination to detect bile acid malabsorption. 4. The results indicate that both the 75SeHCAT test and plasma lathosterol detect bile acid malabsorption in patients with ileal resections for Crohn's disease. However, plasma lathosterol is a simpler and less expensive method.

Metabolism of Oxo-Bile Acids and Characterization of Recombinant 12α-Hydroxysteroid Dehydrogenases from Bile Acid 7α-Dehydroxylating Human Gut Bacteria.

PubMed

Doden, Heidi; Sallam, Lina A; Devendran, Saravanan; Ly, Lindsey; Doden, Greta; Daniel, Steven L; Alves, João M P; Ridlon, Jason M

2018-05-15

Bile acids are important cholesterol-derived nutrient signaling hormones, synthesized in the liver, that act as detergents to solubilize dietary lipids. Bile acid 7α-dehydroxylating gut bacteria generate the toxic bile acids deoxycholic acid and lithocholic acid from host bile acids. The ability of these bacteria to remove the 7-hydroxyl group is partially dependent on 7α-hydroxysteroid dehydrogenase (HSDH) activity, which reduces 7-oxo-bile acids generated by other gut bacteria. 3α-HSDH has an important enzymatic activity in the bile acid 7α-dehydroxylation pathway. 12α-HSDH activity has been reported for the low-activity bile acid 7α-dehydroxylating bacterium Clostridium leptum ; however, this activity has not been reported for high-activity bile acid 7α-dehydroxylating bacteria, such as Clostridium scindens , Clostridium hylemonae , and Clostridium hiranonis Here, we demonstrate that these strains express bile acid 12α-HSDH. The recombinant enzymes were characterized from each species and shown to preferentially reduce 12-oxolithocholic acid to deoxycholic acid, with low activity against 12-oxochenodeoxycholic acid and reduced activity when bile acids were conjugated to taurine or glycine. Phylogenetic analysis suggests that 12α-HSDH is widespread among Firmicutes , Actinobacteria in the Coriobacteriaceae family, and human gut Archaea IMPORTANCE 12α-HSDH activity has been established in the medically important bile acid 7α-dehydroxylating bacteria C. scindens , C. hiranonis , and C. hylemonae Experiments with recombinant 12α-HSDHs from these strains are consistent with culture-based experiments that show a robust preference for 12-oxolithocholic acid over 12-oxochenodeoxycholic acid. Phylogenetic analysis identified novel members of the gut microbiome encoding 12α-HSDH. Future reengineering of 12α-HSDH enzymes to preferentially oxidize cholic acid may provide a means to industrially produce the therapeutic bile acid ursodeoxycholic acid. In addition, a cholic acid-specific 12α-HSDH expressed in the gut may be useful for the reduction in deoxycholic acid concentration, a bile acid implicated in cancers of the gastrointestinal (GI) tract. Copyright © 2018 American Society for Microbiology.

Concanavalin A-binding cholesterol crystallization inhibiting and promoting activity in bile from patients with Crohn's disease compared to patients with ulcerative colitis.

PubMed

Keulemans, Y C; Mok, K S; Slors, J F; Brink, M A; Gouma, D J; Tytgat, G N; Groen, A K

1999-10-01

Crohn's disease is a risk factor for gallstone formation. In contrast, patients with ulcerative colitis have an incidence of gallstone formation comparable to the general population. The reason for this difference is not known. The aim of this study was to elucidate the factors controlling cholesterol crystallization in gallbladder bile of Crohn's disease and ulcerative colitis patients. Gallbladder bile was obtained by aspiration during bowel resections (26 Crohn's disease patients, 20 ulcerative colitis patients). Biliary lipid composition, crystal detection time and the effect of extraction of the concanavalin A-binding fraction on crystal formation were determined. Cholesterol crystals were present in seven of the 26 bile samples of Crohn's disease-patients and one of the 20 ulcerative colitis patients. Four of the bile samples of Crohn's disease patients were fast nucleating. None of the 20 ulcerative colitis patients had fast nucleating bile. Lipid composition, total lipid concentration and CSI were not significantly different between the two groups. In Crohn's disease patients extraction of concanavalin A-binding fraction decreased crystallization in 10 bile samples but accelerated crystallization in one bile sample. In eight bile samples from ulcerative colitis patients crystallization increased after concanavalin A-binding fraction extraction. Compared to ulcerative colitis patients, gallbladder bile of Crohn's disease patients showed increased cholesterol crystallization despite comparable lipid composition and cholesterol saturation index. This difference is caused by increased cholesterol crystallization-promoting activity. Bile from ulcerative colitis patients contains a Con A-binding factor which inhibits cholesterol crystallization.

[Correlation of retinol binding protein 4 with 
metabolic indexes of glucose and 
lipid, bile cholesterol saturation index].

PubMed

Wang, Wen; Li, Nianfeng

2015-06-01

To measure retinol binding protein 4 (RBP4) levels in serum and bile and to analyze their relationship with insulin resistance, dyslipidemia or cholesterol saturation index (CSI).
 A total of 60 patients with gallstone were divided into a diabetes group (n=30) and a control group (n=30). The concentrations of RBP4 in serum and bile were detected by enzyme-linked immunosorbent assay (ELISA). Enzyme colorimetric method was used to measure the concentration of biliary cholesterol, bile acid and phospholipid. Biliary CSI was calculated by Carey table. Partial correlation and multiple linear regression analysis were used to evaluate the correlation between the RBP4 levels in serum or bile and the above indexes.
 The RBP4 concentrations in serum and bile in the diabetes group were significantly elevated compared with those in the control group (both P<0.01). There was no significant difference in the serum total bile acid (TBA), serum triglyceride (TG), serum high-density lipoprotein (HDL), bile TBA, bile total cholesterol (TC) , bile phospholipids and bile CSI between the 2 groups (all P>0.05); but the serum TC, low density lipoprotein (LDL), fasting blood glucose (FBG), fasting insulin (FINS), and homeostasis model assessment for insulin resistance (HOMA-IR) in the diabetes group were significantly increased compared to those in the control group (all P<0.05). The partial correlation analysis, which was adjusted by age, showed that the bile RBP4 was positively correlated with body mass index (BMI), waist circumference (WC), FINS, FBG, TC, LDL and HOMA-IR (r=0.283, 0.405, 0.685, 0.667, 0.553, 0.424 and 0.735, respectively), and the serum RBP4 was also positively correlated with the WC, FINS, FBG, TC, LDL and HOMA-IR (r=0.317, 0.734, 0.609, 0.528, 0.386 and 0.751, respectively). Stepwise multivariate linear regression analysis suggested that the HOMA-IR, BMI and WC were independently correlated with the level of bile RBP4 (multiple regression equation: Ybile RBP4=2.372XHOMA-IR+0.420XBMI+0.178XWC-26.813), and the serum RBP4 level was correlated with the HOMA-IR and WC independently (multiple regression equation: Yserum RBP4=2.832XHOMA-IR +0.235XWC-20.128). Multiple regression equations showed that HOMA-IR was the strongest correlation factor with RBP4.
 RBP4 concentrations in serum and bile in the diabetes group are significantly higher than those in the control group. HOMA-IR, BMI and WC are independently correlated with the level of bile RBP4. HOMA-IR and WC are independently correlated with the serum RBP4 level. HOMA-IR is the strongest correlation factor with RBP4. RBP4 might play an important role in the course of gallstone formation in Type 2 diabetes mellitus.

A new, major C27 biliary bile acid in the Red-winged tinamou (Rhynchotus rufescens):(25R)-1β,3α,7α-trihydroxy-5β-cholestan-27-oic acid*

PubMed Central

Hagey, Lee R.; Kakiyama, Genta; Muto, Akina; Iida, Takashi; Mushiake, Kumiko; Goto, Takaaki; Mano, Nariyasu; Goto, Junichi; Oliveira, Cleida A.; Hofmann, Alan F.

2009-01-01

The chemical structures of the three major bile acids present in the gallbladder bile of the Red-winged tinamou (Rhynchotus rufescens), an early evolving, ground-living bird related to ratites, were determined. Bile acids were isolated by preparative reversed-phase HPLC. Two of the compounds were identified as the taurine N-acylamidates of (25R)-3α,7α-dihydroxy-5β-cholestan-27-oic acid (constituting 22% of biliary bile acids) and (25R)-3α,7α,12α-trihydroxy-5β-cholestan-27-oic acid (constituting 51%). The remaining compound, constituting 21% of biliary bile acids, was an unknown C27 bile acid. Its structure was elucidated by LC/ESI-MS/MS and NMR and shown to be the taurine conjugate of (25R)-1β,3α,7α-trihydroxy-5β-cholestan-27-oic acid, a C27 trihydroxy bile acid not previously reported. Although C27 bile acids with a 1β-hydroxyl group have been identified as trace bile acids in the alligator, this is the first report of a major biliary C27 bile acid possessing a 1β-hydroxyl group. PMID:19011113

Bile salt tolerance of Lactococcus lactis is enhanced by expression of bile salt hydrolase thereby producing less bile acid in the cells.

PubMed

Bi, Jie; Liu, Song; Du, Guocheng; Chen, Jian

2016-04-01

Changes of bile salt tolerance, morphology and amount of bile acid within cells were studied to evaluate the exact effects of bile salt hydrolase (BSH) on bile salt tolerance of microorganism. The effect of BSHs on the bile salt tolerance of Lactococcus lactis was examined by expressing two BSHs (BSH1 and BSH2). Growth of L. lactis expressing BSH1 or BSH2 was better under bile salt stress compared to wild-type L. lactis. As indicated by transmission electron microscopy, bile acids released by the action of BSH induced the formation of micelles around the membrane surface of cells subject to conjugated bile salt stress. A similar micelle containing bile acid was observed in the cytoplasm by liquid chromatography-mass spectrometry. BSH1 produced fewer bile acid micelles in the cytoplasm and achieved better cell growth of L. lactis compared to BSH2. Expression of BSH improved bile salt tolerance of L. lactis but excessive production by BSH of bile acid micelles in the cytoplasm inhibited cell growth.

Bile Acid Metabolism and Signaling

PubMed Central

Chiang, John Y. L.

2015-01-01

Bile acids are important physiological agents for intestinal nutrient absorption and biliary secretion of lipids, toxic metabolites, and xenobiotics. Bile acids also are signaling molecules and metabolic regulators that activate nuclear receptors and G protein-coupled receptor (GPCR) signaling to regulate hepatic lipid, glucose, and energy homeostasis and maintain metabolic homeostasis. Conversion of cholesterol to bile acids is critical for maintaining cholesterol homeostasis and preventing accumulation of cholesterol, triglycerides, and toxic metabolites, and injury in the liver and other organs. Enterohepatic circulation of bile acids from the liver to intestine and back to the liver plays a central role in nutrient absorption and distribution, and metabolic regulation and homeostasis. This physiological process is regulated by a complex membrane transport system in the liver and intestine regulated by nuclear receptors. Toxic bile acids may cause inflammation, apoptosis, and cell death. On the other hand, bile acid-activated nuclear and GPCR signaling protects against inflammation in liver, intestine, and macrophages. Disorders in bile acid metabolism cause cholestatic liver diseases, dyslipidemia, fatty liver diseases, cardiovascular diseases, and diabetes. Bile acids, bile acid derivatives, and bile acid sequestrants are therapeutic agents for treating chronic liver diseases, obesity, and diabetes in humans. PMID:23897684

Association of canalicular membrane enzymes with bile acid micelles and lipid aggregates in human and rat bile.

PubMed

Accatino, L; Pizarro, M; Solís, N; Koenig, C S

1995-01-18

This study was undertaken to gain insights into the characteristics of the polymolecular association between canalicular membrane enzymes, bile acids, cholesterol and phospholipids in bile and into the celular mechanisms whereby the enzymes are secreted into bile. With this purpose, we studied the distribution of bile acids, cholesterol, phospholipids, proteins and representative canalicular membrane enzymes (alkaline phosphatase, 5'-nucleotidase and gamma-glutamyl transpeptidase), which can be considered specific marker constituents, in bile fractions enriched in phospholipid-cholesterol lamellar structures (multilamellar and unilamellar vesicles) and bile acid-mixed micelles. These fractions were isolated by ultracentrifugation from human hepatic bile, normal rat bile and bile of rats treated with diosgenin, a steroid that induces a marked increase in biliary cholesterol secretion, and were characterized by density, lipid composition and transmission electron microscopy. These studies demonstrate that alkaline phosphatase, 5'-nucleotidase and gamma-glutamyl transpeptidase are secreted into both human and rat bile where they are preferentially associated with bile acid-mixed micelles, suggesting a role for bile acids in both release of these enzymes and lipids from the canalicular membrane and solubilization in bile. In addition, heterogeneous association of these enzymes with nonmicellar, lamellar structures in human and rat bile is consistent with the hypothesis that processes independent of the detergent effects of bile acids might also result in the release of specific intrinsic membrane proteins into bile.

Ursodeoxycholic Acid Suppresses Lipogenesis in Mouse Liver: Possible Role of the Decrease in β-Muricholic Acid, a Farnesoid X Receptor Antagonist.

PubMed

Fujita, Kyosuke; Iguchi, Yusuke; Une, Mizuho; Watanabe, Shiro

2017-04-01

The farnesoid X receptor (FXR) is a major nuclear receptor of bile acids; its activation suppresses sterol regulatory element-binding protein 1c (SREBP1c)-mediated lipogenesis and decreases the lipid contents in the liver. There are many reports showing that the administration of ursodeoxycholic acid (UDCA) suppresses lipogenesis and reduces the lipid contents in the liver of experimental animals. Since UDCA is not recognized as an FXR agonist, these effects of UDCA cannot be readily explained by its direct activation of FXR. We observed that the dietary administration of UDCA in mice decreased the expression levels of SREBP1c and its target lipogenic genes. Alpha- and β-muricholic acids (MCA) and cholic acid (CA) were the major bile acids in the mouse liver but their contents decreased upon UDCA administration. The hepatic contents of chenodeoxycholic acid and deoxycholic acid (DCA) were relatively low but were not changed by UDCA. UDCA did not show FXR agonistic or antagonistic potency in in vitro FXR transactivation assay. Taking these together, we deduced that the above-mentioned change in hepatic bile acid composition induced upon UDCA administration might cause the relative increase in the FXR activity in the liver, mainly by the reduction in the content of β-MCA, a farnesoid X receptor antagonist, which suggests a mechanism by which UDCA suppresses lipogenesis and decreases the lipid contents in the mouse liver.

Comparison of endogenous and radiolabeled bile acid excretion in patients with idiopathic chronic diarrhea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiller, L.R.; Bilhartz, L.E.; Santa Ana, C.A.

Fecal recovery of radioactivity after ingestion of a bolus of radiolabeled bile acid is abnormally high in most patients with idiopathic chronic diarrhea. To evaluate the significance of this malabsorption, concurrent fecal excretion of both exogenous radiolabeled bile acid and endogenous (unlabeled) bile acid were measured in patients with idiopathic chronic diarrhea. Subjects received a 2.5-microCi oral dose of taurocholic acid labeled with 14C in the 24th position of the steroid moiety. Endogenous bile acid excretion was measured by a hydroxysteroid dehydrogenase assay on a concurrent 72-h stool collection. Both radiolabeled and endogenous bile acid excretion were abnormally high inmore » most patients with chronic diarrhea compared with normal subjects, even when equivoluminous diarrhea was induced in normal subjects by ingestion of osmotically active solutions. The correlation between radiolabeled and endogenous bile acid excretion was good. However, neither radiolabeled nor endogenous bile acid excretion was as abnormal as is typically seen in patients with ileal resection, and none of these diarrhea patients responded to treatment with cholestyramine with stool weights less than 200 g. These results suggest (a) that this radiolabeled bile acid excretion test accurately reflects excess endogenous bile acid excretion; (b) that excess endogenous bile acid excretion is not caused by diarrhea per se; (c) that spontaneously occurring idiopathic chronic diarrhea is often associated with increased endogenous bile acid excretion; and (d) that bile acid malabsorption is not likely to be the primary cause of diarrhea in most of these patients.« less

Bile acid malabsorption after intestinal bypass surgery for obesity. A comparison between jejunoileal shunt and biliointestinal bypass.

PubMed

Nyhlin, H; Brydon, G; Danielsson, A; Eriksson, F

1990-01-01

Seventeen patients were operated on with intestinal shunts for morbid obesity, in eight a biliointestinal bypass (BI) was constructed and in the rest a conventional jejunoileal (JI)-shunt. The reduction in weight was similar in both groups, and so was malabsorption of fat, but the BI-group had significantly less bowel motions with less watery diarrhoea. Bile acid malabsorption was measured both chemically by estimating the total amount of faecal bile acids excreted, as well as indirectly by using a 75Se-labelled synthetic bile acid (SeHCAT). Both techniques revealed a substantial loss of bile acid after both types of operation, but patients with BI bypass surgery had significantly lower elimination time of the bile acid than those with JI-shunts. There was a significant negative correlation between SeHCAT retention and total faecal bile acids. However, some patients with low SeHCAT retention had normal or even reduced output of faecal bile acids. Estimation of faecal bile acids may display false negative results when the bile acid pool is decreased. The SeHCAT-test seems to be a better technique for measuring bile acid losses. The study suggests that BI bypass surgery for obesity seems to be advantageous over the JI shunt in reducing the postoperative loss of bile acids and choleretic diarrhoea, without influencing the weight loss.

Nuclear factor-E2-related factor 2 is a major determinant of bile acid homeostasis in the liver and intestine

PubMed Central

Weerachayaphorn, Jittima; Mennone, Albert; Soroka, Carol J.; Harry, Kathy; Hagey, Lee R.; Kensler, Thomas W.

2012-01-01

The transcription factor nuclear factor-E2-related factor 2 (Nrf2) is a key regulator for induction of hepatic detoxification and antioxidant mechanisms, as well as for certain hepatobiliary transporters. To examine the role of Nrf2 in bile acid homeostasis and cholestasis, we assessed the determinants of bile secretion and bile acid synthesis and transport before and after bile duct ligation (BDL) in Nrf2−/− mice. Our findings indicate reduced rates of biliary bile acid and GSH excretion, higher levels of intrahepatic bile acids, and decreased expression of regulators of bile acid synthesis, Cyp7a1 and Cyp8b1, in Nrf2−/− compared with wild-type control mice. The mRNA expression of the bile acid transporters bile salt export pump (Bsep) and organic solute transporter (Ostα) were increased in the face of impaired expression of the multidrug resistance-associated proteins Mrp3 and Mrp4. Deletion of Nrf2 also decreased ileal apical sodium-dependent bile acid transporter (Asbt) expression, leading to reduced bile acid reabsorption and increased loss of bile acid in feces. Finally, when cholestasis is induced by BDL, liver injury was not different from that in wild-type BDL mice. These Nrf2−/− mice also had increased pregnane X receptor (Pxr) and Cyp3a11 mRNA expression in association with enhanced hepatic bile acid hydroxylation. In conclusion, this study finds that Nrf2 plays a major role in the regulation of bile acid homeostasis in the liver and intestine. Deletion of Nrf2 results in a cholestatic phenotype but does not augment liver injury following BDL. PMID:22345550

Conjugated bile acids in gallbladder bile and serum as potential biomarkers for cholesterol polyps and adenomatous polyps.

PubMed

Zhao, Mei-Fen; Huang, Peng; Ge, Chun-Lin; Sun, Tao; Ma, Zhi-Gang; Ye, Fei-Fei

2016-02-28

To identify conjugated bile acids in gallbladder bile and serum as possible biomarkers for cholesterol polyps (CPs) and adenomatous polyps (APs). Gallbladder bile samples and serum samples were collected from 18 patients with CPs (CP group), 9 patients with APs (AP group), and 20 patients with gallstones (control group) from March to November, 2013. High performance liquid chromatography (HPLC) assay with ultraviolent detection was used to detect the concentration of 8 conjugated bile acids (glycocholic acid, GCA; taurocholic acid, TCA; glycochenodeoxycholic acid, GCDCA; taurochenodeoxycholic acid, TCDCA; glycodeoxycholic acid, GDCA; taurodeoxycholic acid, TDCA; taurolithocholic acid, TLCA; tauroursodeoxycholic acid, TUDCA) in bile samples and serum samples. The diagnostic efficacy of serum GCA, GCDCA and TCDCA was evaluated. These 8 conjugated bile acids in gallbladder bile and serum were completely identified within 10 minutes with good linearity (correlation coefficient: R>0.9900; linearity range: 3.91-500 µg/mL). Among these conjugated bile acids, the levels of gallbladder bile GCDCA and TCDCA in the CP group were significantly higher than those in the AP group (p<0.05). Furthermore, serum GCDCA and TCDCA as well as GCA were significantly higher in the AP group than the CP group (p<0.05). Serum GCDCA alone (≤12 µg/mL) had relatively better diagnostic efficacy than the other conjugated bile acids. The levels of serum GCA, GCDCA and TCDCA may be valuable for differentiation of APs and CPs.

Bile Acid Signaling in Metabolic Disease and Drug Therapy

PubMed Central

Li, Tiangang

2014-01-01

Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates hepatobiliary secretion of lipids, lipophilic metabolites, and xenobiotics. In the intestine, bile acids are essential for the absorption, transport, and metabolism of dietary fats and lipid-soluble vitamins. Extensive research in the last 2 decades has unveiled new functions of bile acids as signaling molecules and metabolic integrators. The bile acid–activated nuclear receptors farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, and G protein–coupled bile acid receptor play critical roles in the regulation of lipid, glucose, and energy metabolism, inflammation, and drug metabolism and detoxification. Bile acid synthesis exhibits a strong diurnal rhythm, which is entrained by fasting and refeeding as well as nutrient status and plays an important role for maintaining metabolic homeostasis. Recent research revealed an interaction of liver bile acids and gut microbiota in the regulation of liver metabolism. Circadian disturbance and altered gut microbiota contribute to the pathogenesis of liver diseases, inflammatory bowel diseases, nonalcoholic fatty liver disease, diabetes, and obesity. Bile acids and their derivatives are potential therapeutic agents for treating metabolic diseases of the liver. PMID:25073467

Consequences of bile salt biotransformations by intestinal bacteria

PubMed Central

Ridlon, Jason M.; Harris, Spencer C.; Bhowmik, Shiva; Kang, Dae-Joong; Hylemon, Phillip B.

2016-01-01

ABSTRACT Emerging evidence strongly suggest that the human “microbiome” plays an important role in both health and disease. Bile acids function both as detergents molecules promoting nutrient absorption in the intestines and as hormones regulating nutrient metabolism. Bile acids regulate metabolism via activation of specific nuclear receptors (NR) and G-protein coupled receptors (GPCRs). The circulating bile acid pool composition consists of primary bile acids produced from cholesterol in the liver, and secondary bile acids formed by specific gut bacteria. The various biotransformation of bile acids carried out by gut bacteria appear to regulate the structure of the gut microbiome and host physiology. Increased levels of secondary bile acids are associated with specific diseases of the GI system. Elucidating methods to control the gut microbiome and bile acid pool composition in humans may lead to a reduction in some of the major diseases of the liver, gall bladder and colon. PMID:26939849

Transformation of bile acids into iso-bile acids by Clostridium perfringens: possible transport of 3 beta-hydrogen via the coenzyme.

PubMed

Batta, A K; Salen, G; Shefer, S

1985-01-01

We have examined the mechanism for the bacterial transformation of chenodeoxycholic acid and lithocholic acid into the corresponding 3 beta-hydroxy epimers with the use of 3 alpha- and 3 beta-tritiated bile acids. The 3-oxo bile acids were transformed into the 3 alpha- (85%) and 3 beta- (15%) hydroxy bile acids after 20-hr incubation with Clostridium perfringens. Approximately 75% radioactivity was recovered in the aqueous medium when [3 beta-3H]chenodeoxycholic acid or [3 beta-3H]lithocholic acid was incubated with the bacteria, and approximately 15% of radioactivity in the bile acid fraction was associated with the 3 alpha-position of the iso-bile acids. When [3 beta-3H]chenodeoxycholic acid was incubated with unlabeled 3-oxo-5 beta-cholanoic acid, tritiated litho- and iso-lithocholic acids were recovered. These results can be explained only when a 3-oxo intermediate is postulated, and the 3 beta-hydrogen in the bile acids is transferred by the bacterial coenzyme (NAD+ or NADP+) to the 3 alpha-position in the iso-bile acids during the reduction of the 3-oxo compounds.

Berberine-induced Inactivation of Signal Transducer and Activator of Transcription 5 Signaling Promotes Male-specific Expression of a Bile Acid Uptake Transporter*

PubMed Central

Bu, Pengli; Le, Yuan; Zhang, Yue; Zhang, Youcai; Cheng, Xingguo

2017-01-01

Sodium-taurocholate co-transporting polypeptide (Ntcp/NTCP) is the major uptake transporter of bile salts in mouse and human livers. In certain diseases, including endotoxemia, cholestasis, diabetes, and hepatocarcinoma, Ntcp/NTCP expression is markedly reduced, which interferes with enterohepatic circulation of bile salts, impairing the absorption of lipophilic compounds. Therefore, normal Ntcp/NTCP expression in the liver is physiologically important. Berberine is an herbal medicine used historically to improve liver function and has recently been shown to repress STAT signaling. However, berberine effects on Ntcp/NTCP expression are unknown, prompting use to investigate this possible connection. Our results showed that berberine dose-dependently increased Ntcp expression in male mouse liver and decreased taurocholic acid levels in serum but increased them in the liver. In mouse and human hepatoma cells, berberine induced Ntcp/NTCP mRNA and protein expression and increased cellular uptake of [3H] taurocholate. Mechanistically, berberine decreased nuclear protein levels of phospho-JAK2 and phospho-STAT5, thus disrupting the JAK2-STAT5 signaling. Moreover, berberine stimulated luciferase reporter expression from the mouse Ntcp promoter when one putative STAT5 response element (RE) (−1137 bp) was deleted and from the human NTCP promoter when three putative STAT5REs (−2898, −2164, and −691 bp) were deleted. Chromatin immunoprecipitation demonstrated that berberine decreased binding of phospho-STAT5 protein to the−2164 and −691 bp STAT5REs in the human NTCP promoter. In summary, berberine-disrupted STAT5 signaling promoted mouse and human Ntcp/NTCP expression, resulting in enhanced bile acid uptake. Therefore, berberine may be a therapeutic candidate compound for maintaining bile acid homeostasis. PMID:28154180

Berberine-induced Inactivation of Signal Transducer and Activator of Transcription 5 Signaling Promotes Male-specific Expression of a Bile Acid Uptake Transporter.

PubMed

Bu, Pengli; Le, Yuan; Zhang, Yue; Zhang, Youcai; Cheng, Xingguo

2017-03-17

Sodium-taurocholate co-transporting polypeptide (Ntcp/NTCP) is the major uptake transporter of bile salts in mouse and human livers. In certain diseases, including endotoxemia, cholestasis, diabetes, and hepatocarcinoma, Ntcp/NTCP expression is markedly reduced, which interferes with enterohepatic circulation of bile salts, impairing the absorption of lipophilic compounds. Therefore, normal Ntcp/NTCP expression in the liver is physiologically important. Berberine is an herbal medicine used historically to improve liver function and has recently been shown to repress STAT signaling. However, berberine effects on Ntcp/NTCP expression are unknown, prompting use to investigate this possible connection. Our results showed that berberine dose-dependently increased Ntcp expression in male mouse liver and decreased taurocholic acid levels in serum but increased them in the liver. In mouse and human hepatoma cells, berberine induced Ntcp/NTCP mRNA and protein expression and increased cellular uptake of [3H] taurocholate. Mechanistically, berberine decreased nuclear protein levels of phospho-JAK2 and phospho-STAT5, thus disrupting the JAK2-STAT5 signaling. Moreover, berberine stimulated luciferase reporter expression from the mouse Ntcp promoter when one putative STAT5 response element (RE) (-1137 bp) was deleted and from the human NTCP promoter when three putative STAT5REs (-2898, -2164, and -691 bp) were deleted. Chromatin immunoprecipitation demonstrated that berberine decreased binding of phospho-STAT5 protein to the-2164 and -691 bp STAT5REs in the human NTCP promoter. In summary, berberine-disrupted STAT5 signaling promoted mouse and human Ntcp/NTCP expression, resulting in enhanced bile acid uptake. Therefore, berberine may be a therapeutic candidate compound for maintaining bile acid homeostasis. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Microbiota transplantation restores normal fecal bile acid composition in recurrent Clostridium difficile infection.

PubMed

Weingarden, Alexa R; Chen, Chi; Bobr, Aleh; Yao, Dan; Lu, Yuwei; Nelson, Valerie M; Sadowsky, Michael J; Khoruts, Alexander

2014-02-15

Fecal microbiota transplantation (FMT) has emerged as a highly effective therapy for refractory, recurrent Clostridium difficile infection (CDI), which develops following antibiotic treatments. Intestinal microbiota play a critical role in the metabolism of bile acids in the colon, which in turn have major effects on the lifecycle of C. difficile bacteria. We hypothesized that fecal bile acid composition is altered in patients with recurrent CDI and that FMT results in its normalization. General metabolomics and targeted bile acid analyses were performed on fecal extracts from patients with recurrent CDI treated with FMT and their donors. In addition, 16S rRNA gene sequencing was used to determine the bacterial composition of pre- and post-FMT fecal samples. Taxonomic bacterial composition of fecal samples from FMT recipients showed rapid change and became similar to the donor after the procedure. Pre-FMT fecal samples contained high concentrations of primary bile acids and bile salts, while secondary bile acids were nearly undetectable. In contrast, post-FMT fecal samples contained mostly secondary bile acids, as did non-CDI donor samples. Therefore, our analysis showed that FMT resulted in normalization of fecal bacterial community structure and metabolic composition. Importantly, metabolism of bile salts and primary bile acids to secondary bile acids is disrupted in patients with recurrent CDI, and FMT corrects this abnormality. Since individual bile salts and bile acids have pro-germinant and inhibitory activities, the changes suggest that correction of bile acid metabolism is likely a major mechanism by which FMT results in a cure and prevents recurrence of CDI.

Role of bile acids in carcinogenesis of pancreatic cancer: An old topic with new perspective

PubMed Central

Feng, Hui-Yi; Chen, Yang-Chao

2016-01-01

The role of bile acids in colorectal cancer has been well documented, but their role in pancreatic cancer remains unclear. In this review, we examined the risk factors of pancreatic cancer. We found that bile acids are associated with most of these factors. Alcohol intake, smoking, and a high-fat diet all lead to high secretion of bile acids, and bile acid metabolic dysfunction is a causal factor of gallstones. An increase in secretion of bile acids, in addition to a long common channel, may result in bile acid reflux into the pancreatic duct and to the epithelial cells or acinar cells, from which pancreatic adenocarcinoma is derived. The final pathophysiological process is pancreatitis, which promotes dedifferentiation of acinar cells into progenitor duct-like cells. Interestingly, bile acids act as regulatory molecules in metabolism, affecting adipose tissue distribution, insulin sensitivity and triglyceride metabolism. As a result, bile acids are associated with three risk factors of pancreatic cancer: obesity, diabetes and hypertriglyceridemia. In the second part of this review, we summarize several studies showing that bile acids act as cancer promoters in gastrointestinal cancer. However, more question are raised than have been solved, and further oncological and physiological experiments are needed to confirm the role of bile acids in pancreatic cancer carcinogenesis. PMID:27672269

Serum bile acid concentrations in dairy cattle with hepatic lipidosis.

PubMed

Garry, F B; Fettman, M J; Curtis, C R; Smith, J A

1994-01-01

This study was designed to evaluate serum bile acid measurements as indicatory, of liver function and/or hepatic fat infiltration in dairy cattle. Serum bile acid concentrations were measured in healthy dairy cattle at different stages of lactation after fasting or feeding. Bile acid concentrations were compared with liver fat content and sulfobromophthalein (BSP) half-life (T 1/2). Serum bile acid concentrations were higher in cows in early lactation and with higher daily milk production. Compared with prefasting values, bile acid concentrations were decreased at 8, 14, and 24 hours of fasting. Blood samples from fed cows at 1- to 2-hour intervals had wide and inconsistent variations in bile acid concentration. Because serum bile acids correlated well with BSP T 1/2, it is suggested that both measurements evaluate a similar aspect of liver function. Neither bile acids nor BSP T 1/2 correlated with differences in liver fat content among cows. Because of large variability in serum bile acid concentrations in fed cows and the lack of correlation of measured values with liver fat content, bile acid determinations do not appear useful for showing changes in hepatic function in fed cows with subclinical hepatic lipidosis nor serve as a screening test for this condition.

A simple and accurate HPLC method for fecal bile acid profile in healthy and cirrhotic subjects: validation by GC-MS and LC-MS[S

PubMed Central

Kakiyama, Genta; Muto, Akina; Takei, Hajime; Nittono, Hiroshi; Murai, Tsuyoshi; Kurosawa, Takao; Hofmann, Alan F.; Pandak, William M.; Bajaj, Jasmohan S.

2014-01-01

We have developed a simple and accurate HPLC method for measurement of fecal bile acids using phenacyl derivatives of unconjugated bile acids, and applied it to the measurement of fecal bile acids in cirrhotic patients. The HPLC method has the following steps: 1) lyophilization of the stool sample; 2) reconstitution in buffer and enzymatic deconjugation using cholylglycine hydrolase/sulfatase; 3) incubation with 0.1 N NaOH in 50% isopropanol at 60°C to hydrolyze esterified bile acids; 4) extraction of bile acids from particulate material using 0.1 N NaOH; 5) isolation of deconjugated bile acids by solid phase extraction; 6) formation of phenacyl esters by derivatization using phenacyl bromide; and 7) HPLC separation measuring eluted peaks at 254 nm. The method was validated by showing that results obtained by HPLC agreed with those obtained by LC-MS/MS and GC-MS. We then applied the method to measuring total fecal bile acid (concentration) and bile acid profile in samples from 38 patients with cirrhosis (17 early, 21 advanced) and 10 healthy subjects. Bile acid concentrations were significantly lower in patients with advanced cirrhosis, suggesting impaired bile acid synthesis. PMID:24627129

Bile acid-induced necrosis in primary human hepatocytes and in patients with obstructive cholestasis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woolbright, Benjamin L.; Dorko, Kenneth; Antoine, Daniel J.

Accumulation of bile acids is a major mediator of cholestatic liver injury. Recent studies indicate bile acid composition between humans and rodents is dramatically different, as humans have a higher percent of glycine conjugated bile acids and increased chenodeoxycholate content, which increases the hydrophobicity index of bile acids. This increase may lead to direct toxicity that kills hepatocytes, and promotes inflammation. To address this issue, this study assessed how pathophysiological concentrations of bile acids measured in cholestatic patients affected primary human hepatocytes. Individual bile acid levels were determined in serum and bile by UPLC/QTOFMS in patients with extrahepatic cholestasis with,more » or without, concurrent increases in serum transaminases. Bile acid levels increased in serum of patients with liver injury, while biliary levels decreased, implicating infarction of the biliary tracts. To assess bile acid-induced toxicity in man, primary human hepatocytes were treated with relevant concentrations, derived from patient data, of the model bile acid glycochenodeoxycholic acid (GCDC). Treatment with GCDC resulted in necrosis with no increase in apoptotic parameters. This was recapitulated by treatment with biliary bile acid concentrations, but not serum concentrations. Marked elevations in serum full-length cytokeratin-18, high mobility group box 1 protein (HMGB1), and acetylated HMGB1 confirmed inflammatory necrosis in injured patients; only modest elevations in caspase-cleaved cytokeratin-18 were observed. These data suggest human hepatocytes are more resistant to human-relevant bile acids than rodent hepatocytes, and die through necrosis when exposed to bile acids. These mechanisms of cholestasis in humans are fundamentally different to mechanisms observed in rodent models. - Highlights: • Cholestatic liver injury is due to cytoplasmic bile acid accumulation in hepatocytes. • Primary human hepatocytes are resistant to BA-induced injury compared to rodents. • Primary human hepatocytes largely undergo necrosis in response to BA toxicity. • Cholestatic liver injury in vivo is predominantly necrotic with minor apoptosis. • Rodent models of bile acid toxicity may not recapitulate the injury in man.« less

Preference of Conjugated Bile Acids over Unconjugated Bile Acids as Substrates for OATP1B1 and OATP1B3

PubMed Central

Suga, Takahiro; Sato, Toshihiro; Maekawa, Masamitsu; Goto, Junichi; Mano, Nariyasu

2017-01-01

Bile acids, the metabolites of cholesterol, are signaling molecules that play critical role in many physiological functions. They undergo enterohepatic circulation through various transporters expressed in intestine and liver. Human organic anion-transporting polypeptides (OATP) 1B1 and OATP1B3 contribute to hepatic uptake of bile acids such as taurocholic acid. However, the transport properties of individual bile acids are not well understood. Therefore, we selected HEK293 cells overexpressing OATP1B1 and OATP1B3 to evaluate the transport of five major human bile acids (cholic acid, chenodeoxycholic acid, deoxycholic acid, ursodeoxycholic acid, lithocholic acid) together withtheir glycine and taurine conjugates via OATP1B1 and OATP1B3. The bile acids were quantified by liquid chromatography-tandem mass spectrometry. The present study revealed that cholic acid, chenodeoxyxcholic acid, and deoxycholic acid were transported by OATP1B1 and OATP1B3, while ursodeoxycholic acid and lithocholic acid were not significantly transported by OATPs. However, all the conjugated bile acids were taken up rapidly by OATP1B1 and OATP1B3. Kinetic analyses revealed the involvement of saturable OATP1B1- and OATP1B3-mediated transport of bile acids. The apparent Km values for OATP1B1 and OATP1B3 of the conjugated bile acids were similar (0.74–14.7 μM for OATP1B1 and 0.47–15.3 μM for OATP1B3). They exhibited higher affinity than cholic acid (47.1 μM for OATP1B1 and 42.2 μM for OATP1B3). Our results suggest that conjugated bile acids (glycine and taurine) are preferred to unconjugated bile acids as substrates for OATP1B1 and OATP1B3. PMID:28060902

[Correlations of bile acids in the bile of rats in conditions of alloxan induced diabetes melitus].

PubMed

Danchenko, N M; Vesel'skyĭ, S P; Tsudzevych, B O

2014-01-01

The ratio of bile acids in the bile of rats with alloxan diabetes was investigated using the method of thin-layer chromatography. Changes of coefficients of conjugation and hydroxylation of bile acids were calculated and analyzed in half-hour samples of bile obtained during the 3-hour experiment. It has been found that the processes of conjugation of cholic acid with glycine and taurine are inhibited in alloxan diabetes. At the same time a significant increase of free threehydroxycholic and dixydroxycholic bile acids and conjugates of the latter ones with taurine has been registered. Coefficients of hydroxylation in alloxan diabetes show the domination of "acidic" pathway in bile acid biosynthesis that is tightly connected with the activity of mitochondrial enzymes.

Obeticholic acid, a selective farnesoid X receptor agonist, regulates bile acid homeostasis in sandwich-cultured human hepatocytes.

PubMed

Zhang, Yuanyuan; Jackson, Jonathan P; St Claire, Robert L; Freeman, Kimberly; Brouwer, Kenneth R; Edwards, Jeffrey E

2017-08-01

Farnesoid X receptor (FXR) is a master regulator of bile acid homeostasis through transcriptional regulation of genes involved in bile acid synthesis and cellular membrane transport. Impairment of bile acid efflux due to cholangiopathies results in chronic cholestasis leading to abnormal elevation of intrahepatic and systemic bile acid levels. Obeticholic acid (OCA) is a potent and selective FXR agonist that is 100-fold more potent than the endogenous ligand chenodeoxycholic acid (CDCA). The effects of OCA on genes involved in bile acid homeostasis were investigated using sandwich-cultured human hepatocytes. Gene expression was determined by measuring mRNA levels. OCA dose-dependently increased fibroblast growth factor-19 (FGF-19) and small heterodimer partner (SHP) which, in turn, suppress mRNA levels of cholesterol 7-alpha-hydroxylase (CYP7A1), the rate-limiting enzyme for de novo synthesis of bile acids. Consistent with CYP7A1 suppression, total bile acid content was decreased by OCA (1 μmol/L) to 42.7 ± 20.5% relative to control. In addition to suppressing de novo bile acids synthesis, OCA significantly increased the mRNA levels of transporters involved in bile acid homeostasis. The bile salt excretory pump (BSEP), a canalicular efflux transporter, increased by 6.4 ± 0.8-fold, and the basolateral efflux heterodimer transporters, organic solute transporter α (OST α ) and OST β increased by 6.4 ± 0.2-fold and 42.9 ± 7.9-fold, respectively. The upregulation of BSEP and OST α and OST β, by OCA reduced the intracellular concentrations of d 8 -TCA, a model bile acid, to 39.6 ± 8.9% relative to control. These data demonstrate that OCA does suppress bile acid synthesis and reduce hepatocellular bile acid levels, supporting the use of OCA to treat bile acid-induced toxicity observed in cholestatic diseases. © 2017 Intercept Pharmaceuticals. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics.

AP-1 Inhibition by SR 11302 Protects Human Hepatoma HepG2 Cells from Bile Acid-Induced Cytotoxicity by Restoring the NOS-3 Expression

PubMed Central

González-Rubio, Sandra; Linares, Clara I.; Aguilar-Melero, Patricia; Rodríguez-Perálvarez, Manuel; Montero-Álvarez, José L.

2016-01-01

The harmful effects of bile acid accumulation occurring during cholestatic liver diseases have been associated with oxidative stress increase and endothelial nitric oxide synthase (NOS-3) expression decrease in liver cells. We have previously reported that glycochenodeoxycholic acid (GCDCA) down-regulates gene expression by increasing SP1 binding to the NOS-3 promoter in an oxidative stress dependent manner. In the present study, we aimed to investigate the role of transcription factor (TF) AP-1 on the NOS-3 deregulation during GCDCA-induced cholestasis. The cytotoxic response to GCDCA was characterized by 1) the increased expression and activation of TFs cJun and c-Fos; 2) a higher binding capability of these at position -666 of the NOS-3 promoter; 3) a decrease of the transcriptional activity of the promoter and the expression and activity of NOS-3; and 4) the expression increase of cyclin D1. Specific inhibition of AP-1 by the retinoid SR 11302 counteracted the cytotoxic effects induced by GCDCA while promoting NOS-3 expression recovery and cyclin D1 reduction. NOS activity inhibition by L-NAME inhibited the protective effect of SR 11302. Inducible NOS isoform was no detected in this experimental model of cholestasis. Our data provide direct evidence for the involvement of AP-1 in the NOS-3 expression regulation during cholestasis and define a critical role for NOS-3 in regulating the expression of cyclin D1 during the cell damage induced by bile acids. AP-1 appears as a potential therapeutic target in cholestatic liver diseases given its role as a transcriptional repressor of NOS-3. PMID:27490694

Nocturnal weakly acidic reflux promotes aspiration of bile acids in lung transplant recipients.

PubMed

Blondeau, Kathleen; Mertens, Veerle; Vanaudenaerde, Bart A; Verleden, Geert M; Van Raemdonck, Dirk E; Sifrim, Daniel; Dupont, Lieven J

2009-02-01

Gastroesophageal reflux (GER) and aspiration of bile acids have been implicated as non-alloimmune risk factors for the development of bronchiolitis obliterans syndrome (BOS) after lung transplantation. The aim of our study was to investigate the association between GER and gastric aspiration of bile acids and to establish which reflux characteristics may promote aspiration of bile acids into the lungs and may feature as a potential diagnostic tool in identifying lung transplantation (LTx) patients at risk for aspiration. Twenty-four stable LTx recipients were studied 1 year after transplantation. All patients underwent 24-hour ambulatory impedance-pH recording for the detection of acid (pH <4) and weakly acidic (pH 4 to 7) reflux. On the same day, bronchoalveolar lavage fluid (BALF) was collected and then analyzed for the presence of bile acids (Bioquant enzymatic assay). Increased GER was detected in 13 patients, of whom 9 had increased acid reflux and 4 had exclusively increased weakly acidic reflux. Sixteen patients had detectable bile acids in the BALF (0.6 [0.4 to 1.5] micromol/liter). The 24-hour esophageal volume exposure was significantly increased in patients with bile acids compared to patients without bile acids in the BALF. Acid exposure and the number of reflux events (total, acid and weakly acidic) were unrelated to the presence of bile acids in the BALF. However, both nocturnal volume exposure and the number of nocturnal weakly acidic reflux events were significantly higher in patients with bile acids in the BALF. Weakly acidic reflux events, especially during the night, are associated with the aspiration of bile acids in LTx recipients and may therefore feature as a potential risk factor for the development of BOS.

Bile acids induce arrhythmias in human atrial myocardium--implications for altered serum bile acid composition in patients with atrial fibrillation.

PubMed

Rainer, Peter P; Primessnig, Uwe; Harenkamp, Sandra; Doleschal, Bernhard; Wallner, Markus; Fauler, Guenter; Stojakovic, Tatjana; Wachter, Rolf; Yates, Ameli; Groschner, Klaus; Trauner, Michael; Pieske, Burkert M; von Lewinski, Dirk

2013-11-01

High bile acid serum concentrations have been implicated in cardiac disease, particularly in arrhythmias. Most data originate from in vitro studies and animal models. We tested the hypotheses that (1) high bile acid concentrations are arrhythmogenic in adult human myocardium, (2) serum bile acid concentrations and composition are altered in patients with atrial fibrillation (AF) and (3) the therapeutically used ursodeoxycholic acid has different effects than other potentially toxic bile acids. Multicellular human atrial preparations ('trabeculae') were exposed to primary bile acids and the incidence of arrhythmic events was assessed. Bile acid concentrations were measured in serum samples from 250 patients and their association with AF and ECG parameters analysed. Additionally, we conducted electrophysiological studies in murine myocytes. Taurocholic acid (TCA) concentration-dependently induced arrhythmias in atrial trabeculae (14/28 at 300 µM TCA, p<0.01) while ursodeoxycholic acid did not. Patients with AF had significantly decreased serum levels of ursodeoxycholic acid conjugates and increased levels of non-ursodeoxycholic bile acids. In isolated myocytes, TCA depolarised the resting membrane potential, enhanced Na(+)/Ca(2+) exchanger (NCX) tail current density and induced afterdepolarisations. Inhibition of NCX prevented arrhythmias in atrial trabeculae. High TCA concentrations induce arrhythmias in adult human atria while ursodeoxycholic acid does not. AF is associated with higher serum levels of non-ursodeoxycholic bile acid conjugates and low levels of ursodeoxycholic acid conjugates. These data suggest that higher levels of toxic (arrhythmogenic) and low levels of protective bile acids create a milieu with a decreased arrhythmic threshold and thus may facilitate arrhythmic events.

Bile acid excess induces cardiomyopathy and metabolic dysfunctions in the heart

PubMed Central

Desai, Moreshwar; Mathur, Bhoomika; Eblimit, Zeena; Vasquez, Hernan; Taegtmeyer, Heinrich; Karpen, Saul; Penny, Daniel J.; Moore, David D.; Anakk, Sayeepriyadarshini

2017-01-01

Cardiac dysfunction in patients with liver cirrhosis is strongly associated with increased serum bile acid concentrations. Here we show that excess bile acids decrease fatty acid oxidation in cardiomyocytes and can cause heart dysfunction, a cardiac syndrome that we term Cholecardia. Fxr; Shp double knockout (DKO) mice, a model for bile acid overload, display cardiac hypertrophy, bradycardia, and exercise intolerance. In addition, DKO mice exhibit an impaired cardiac response to catecholamine challenge. Consistent with this decreased cardiac function, we show that elevated serum bile acids reduce cardiac fatty acid oxidation both in vivo and ex vivo. We find that increased bile acid levels suppress expression of Pgc1α, a key regulator of fatty acid metabolism, and that Pgc1α overexpression in cardiac cells was able to rescue the bile acid-mediated reduction in fatty acid oxidation genes. Importantly, intestinal bile acid sequestration with cholestyramine was sufficient to reverse the observed heart dysfunction in the DKO mice. Conclusions Overall, we propose that decreased Pgc1α expression contributes to the metabolic dysfunction in Cholecardia, and that reducing serum bile acid concentrations will be beneficial against metabolic and pathological changes in the heart. PMID:27774647

Taurocholic acid metabolism by gut microbes and colon cancer

PubMed Central

Ridlon, Jason M.; Wolf, Patricia G.; Gaskins, H. Rex

2016-01-01

ABSTRACT Colorectal cancer (CRC) is one of the most frequent causes of cancer death worldwide and is associated with adoption of a diet high in animal protein and saturated fat. Saturated fat induces increased bile secretion into the intestine. Increased bile secretion selects for populations of gut microbes capable of altering the bile acid pool, generating tumor-promoting secondary bile acids such as deoxycholic acid and lithocholic acid. Epidemiological evidence suggests CRC is associated with increased levels of DCA in serum, bile, and stool. Mechanisms by which secondary bile acids promote CRC are explored. Furthermore, in humans bile acid conjugation can vary by diet. Vegetarian diets favor glycine conjugation while diets high in animal protein favor taurine conjugation. Metabolism of taurine conjugated bile acids by gut microbes generates hydrogen sulfide, a genotoxic compound. Thus, taurocholic acid has the potential to stimulate intestinal bacteria capable of converting taurine and cholic acid to hydrogen sulfide and deoxycholic acid, a genotoxin and tumor-promoter, respectively. PMID:27003186

Activation of the Farnesoid X Receptor Induces Hepatic Expression and Secretion of Fibroblast Growth Factor 21*

PubMed Central

Cyphert, Holly A.; Ge, Xuemei; Kohan, Alison B.; Salati, Lisa M.; Zhang, Yanqiao; Hillgartner, F. Bradley

2012-01-01

Previous studies have shown that starvation or consumption of a high fat, low carbohydrate (HF-LC) ketogenic diet induces hepatic fibroblast growth factor 21 (FGF21) gene expression in part by activating the peroxisome proliferator-activated receptor-α (PPARα). Using primary hepatocyte cultures to screen for endogenous signals that mediate the nutritional regulation of FGF21 expression, we identified two sources of PPARα activators (i.e. nonesterified unsaturated fatty acids and chylomicron remnants) that induced FGF21 gene expression. In addition, we discovered that natural (i.e. bile acids) and synthetic (i.e. GW4064) activators of the farnesoid X receptor (FXR) increased FGF21 gene expression and secretion. The effects of bile acids were additive with the effects of nonesterified unsaturated fatty acids in regulating FGF21 expression. FXR activation of FGF21 gene transcription was mediated by an FXR/retinoid X receptor binding site in the 5′-flanking region of the FGF21 gene. FGF19, a gut hormone whose expression and secretion is induced by intestinal bile acids, also increased hepatic FGF21 secretion. Deletion of FXR in mice suppressed the ability of an HF-LC ketogenic diet to induce hepatic FGF21 gene expression. The results of this study identify FXR as a new signaling pathway activating FGF21 expression and provide evidence that FXR activators work in combination with PPARα activators to mediate the stimulatory effect of an HF-LC ketogenic diet on FGF21 expression. We propose that the enhanced enterohepatic flux of bile acids during HF-LC consumption leads to activation of hepatic FXR and FGF19 signaling activity and an increase in FGF21 gene expression and secretion. PMID:22661717

Determination of bile acid pool size, turnover time, and distribution of male broiler chicks during the first 6 weeks posthatch using SEHCAT, a gamma ray-emitting bile acid analogue.

PubMed

Green, J; Kellogg, T; Keirs, R; Cooper, R

1987-11-01

A bile acid analogue, SEHCAT (tauro-23-75SE-selena-homocholic acid), was used to determine bile acid pool size, turnover time, and distribution in the developing broiler chick. Bile acid pool size was significantly affected by age and followed a quintic trend (a fifth degree polynomial). It remained steady until 30 days of age when it decreased significantly and then rose significantly at 37 days of age. The bile acid pool half-life remained constant until 28 days of age when it increased significantly and then held steady until it increased again at 8 wk of age following a quartic trend. The distribution of bile acids was affected by age with the amount in the gizzard, duodenum, cloaca, liver, and gall bladder varying significantly with age. Jejunal, ileal, and cecal bile acids did not vary significantly with age. Liver bile acid levels followed a quintic trend, rising until 23 days of age and dropping sharply at 30 days of age and holding steady.

3 alpha-Hydroxylated bile acid profiles in clinically normal cats, cats with severe hepatic lipidosis, and cats with complete extrahepatic bile duct occlusion.

PubMed

Center, S A; Thompson, M; Guida, L

1993-05-01

Concentrations of 3 alpha-hydroxylated bile acids were measured in serum and urine of clinically normal (healthy) cats (n = 6), cats with severe hepatic lipidosis (n = 9), and cats with complete bile duct occlusion (n = 4). Bile acid concentrations were measured by use of a gradient flow high-performance liquid chromatography procedure with an acetonitrile and ammonium phosphate mobile phase and an in-line postanalytic column containing 3 alpha-hydroxy-steroid dehydrogenase and a fluorescence detector. Specific identification of all bile acid peaks was not completed; unidentified moieties were represented in terms of their elution time (in minutes). Significant differences in serum and urine bile acid concentrations, quantitative and proportional, were determined among groups of cats. Cats with hepatic lipidosis and bile duct occlusion had significantly (P > or = 0.05) greater total serum and urine bile acids concentrations than did healthy cats. The proportion of hydrophobic bile acids in serum, those eluting at > or = 400 minutes, was 1.9% for healthy cats, 3.3% for cats with lipidosis, and 5.4% for bile duct-obstructed cats. Both groups of ill cats had a broader spectrum of unidentified late-eluting serum bile acids than did healthy cats; the largest spectrum developed in bile duct-occluded cats.(ABSTRACT TRUNCATED AT 250 WORDS)

A Surgical Model in Male Obese Rats Uncovers Protective Effects of Bile Acids Post-Bariatric Surgery

PubMed Central

Setchell, Kenneth DR; Kirby, Michelle; Myronovych, Andriy; Ryan, Karen K.; Ibrahim, Samar H.; Berger, Jose; Smith, Kathi; Toure, Mouhamadoul; Woods, Stephen C.; Seeley, Randy J.

2013-01-01

Bariatric surgery elevates serum bile acids. Conjugated bile acid administration, such as tauroursodeoxycholic acid (TUDCA), improves insulin sensitivity, whereas short-circuiting bile acid circulation through ileal interposition surgery in rats raises TUDCA levels. We hypothesized that bariatric surgery outcomes could be recapitulated by short circuiting the normal enterohepatic bile circulation. We established a model wherein male obese rats underwent either bile diversion (BD) or Sham (SH) surgery. The BD group had a catheter inserted into the common bile duct and its distal end anchored into the middistal jejunum for 4–5 weeks. Glucose tolerance, insulin and glucagon-like peptide-1 (GLP-1) response, hepatic steatosis, and endoplasmic reticulum (ER) stress were measured. Rats post-BD lost significantly more weight than the SH rats. BD rats gained less fat mass after surgery. BD rats had improved glucose tolerance, increased higher postprandial glucagon-like peptide-1 response and serum bile acids but less liver steatosis. Serum bile acid levels including TUDCA concentrations were higher in BD compared to SH pair-fed rats. Fecal bile acid levels were not different. Liver ER stress (C/EBP homologous protein mRNA and pJNK protein) was decreased in BD rats. Bile acid gavage (TUDCA/ursodeoxycholic acid [UDCA]) in diet-induced obese rats, elevated serum TUDCA and concomitantly reduced hepatic steatosis and ER stress (C/EBP homologous protein mRNA). These data demonstrate the ability of alterations in bile acids to recapitulate important metabolic improvements seen after bariatric surgery. Further, our work establishes a model for focused study of bile acids in the context of bariatric surgery that may lead to the identification of therapeutics for metabolic disease. PMID:23592746

Bile acids. XLIV, quantitation of bile acids from the bile fistula rat given (4-14C) cholesterol.

PubMed

Siegfried, C M; Doisy, E A; Elliott, W H

1975-01-24

The bile acids derived from [4-14-C]cholesterol administered intracardially to rats with cannulated bile ducts were identified and quantitated. Over a period of 28 days about 90% of the administered 14-C was found in bile of which 73% was retained in the biliary acid fraction. [7beta-3-H]cholic acid, alpha-muri[3beta-3-H]cholic acid, beta-muri[3beta-3-H]cholic acid and litho[3beta-3-H]cholic acid were prepared with specific activities of about 30 muCi/mg by reduction of appropriate ketonic precursors with NaB3H4 and were added to the biliary acid fraction. After separation and purification of the bile acids, cholic, chenodeoxycholic, alpha- and beta-muricholic acids accounted for 70, 16, 7.5 and 6.1%, respectively, of the 14-C in the biliary acid fraction. The specific activities of these isolated 14-C-labeled acids were almost identical. Lithocholic acid accounted for a maximum of 0.2% and ursodeoxycholic acid and 7-oxolithocholic acid could account for no more than 2% of the biliary 14-C. Gas-liquid chromatography on 3% OV-17 of the trimethylsilyl ether derivatives of the methyl esters of the common bile acids of rat bile results in their complete separation and provides a convenient means of estimating the relative proportions of these acids in rat bile. By this method, the relative amounts of the four major acids, cholic, chenodeoxycholic, alpha- and beta-muricholic acids were 63, 20, 8 and 6%, respectively.

Review article: bile acid diarrhoea - pathogenesis, diagnosis and management.

PubMed

Mottacki, N; Simrén, M; Bajor, A

2016-04-01

Bile acid diarrhoea results from imbalances in the homoeostasis of bile acids in the enterohepatic circulation. It can be a consequence of ileal disease/dysfunction, associated with other GI pathology or can be idiopathic. To summarise the different types of bile acid diarrhoea and discuss the currently available diagnostic methods and treatments. Bile acid diarrhoea is found in up to 40% of patients diagnosed as having functional diarrhoea/IBS-D, and in up to 80% of patients who have undergone ileal resection. It is likely under-diagnosed and under-treated. In idiopathic disease, errors in regulation feedback of fibroblast growth factor 19 contribute to the development of the condition. Clinical therapeutic trials for bile acid diarrhoea have been used to diagnose it, but the 75 SeHCAT test is the primary current method. It is sensitive, specific and widely available, though not in the USA. Other diagnostic methods (such as serum measurement of the bile acid intermediate 7α-hydroxy-4-cholesten-3-one, or C4) have less widespread availability and documentation, and some (such as faecal measurement of bile acids) are significantly more complex and costly. First-line treatment of bile acid diarrhoea is with the bile acid sequestrant cholestyramine, which can be difficult to administer and dose due to gastrointestinal side effects. These side effects are less prominent in newer agents such as colesevelam, which may provide higher efficacy, tolerability and compliance. Bile acid diarrhoea is common, and likely under-diagnosed. Bile acid diarrhoea should be considered relatively early in the differential diagnosis of chronic diarrhoea. © 2016 John Wiley & Sons Ltd.

UV-induced solvent free synthesis of truxillic acid-bile acid conjugates

NASA Astrophysics Data System (ADS)

Koivukorpi, Juha; Kolehmainen, Erkki

2009-07-01

The solvent free UV-induced [2 + 2] intermolecular cycloaddition of two molecules of 3α-cinnamic acid ester of methyl lithocholate produced in 99% yield of α- and ɛ-truxillic acid-bis(methyl lithocholate) isomers, which possess two structurally different potential binding sites. A prerequisite for this effective solid state reaction is a proper self-assembled crystal structure of the starting conjugate crystallized from acetonitrile. The crystallization of cinnamic acid ester of methyl lithocholate from acetonitrile produces two different crystalline forms (polymorphs), which is the reason for the solid state formation of two isomers of truxillic acid-bis(methyl lithocholate).

Megalin and cubilin expression in gallbladder epithelium and regulation by bile acids.

PubMed

Erranz, Benjamín; Miquel, Juan Francisco; Argraves, W Scott; Barth, Jeremy L; Pimentel, Fernando; Marzolo, María-Paz

2004-12-01

Cholesterol crystal formation in the gallbladder is a key step in gallstone pathogenesis. Gallbladder epithelial cells might prevent luminal gallstone formation through a poorly understood cholesterol absorption process. Genetic studies in mice have highlighted potential gallstone susceptibility alleles, Lith genes, which include the gene for megalin. Megalin, in conjunction with the large peripheral membrane protein cubilin, mediates the endocytosis of numerous ligands, including HDL/apolipoprotein A-I (apoA-I). Although the bile contains apoA-I and several cholesterol-binding megalin ligands, the expression of megalin and cubilin in the gallbladder has not been investigated. Here, we show that both proteins are expressed by human and mouse gallbladder epithelia. In vitro studies using a megalin-expressing cell line showed that lithocholic acid strongly inhibits and cholic and chenodeoxycholic acids increase megalin expression. The effects of bile acids (BAs) were also demonstrated in vivo, analyzing gallbladder levels of megalin and cubilin from mice fed with different BAs. The BA effects could be mediated by the farnesoid X receptor, expressed in the gallbladder. Megalin protein was also strongly increased after feeding a lithogenic diet. These results indicate a physiological role for megalin and cubilin in the gallbladder and provide support for a role for megalin in gallstone pathogenesis.

Impact of Gut Microbiota-Mediated Bile Acid Metabolism on the Solubilization Capacity of Bile Salt Micelles and Drug Solubility.

PubMed

Enright, Elaine F; Joyce, Susan A; Gahan, Cormac G M; Griffin, Brendan T

2017-04-03

In recent years, the gut microbiome has gained increasing appreciation as a determinant of the health status of the human host. Bile salts that are secreted into the intestine may be biotransformed by enzymes produced by the gut bacteria. To date, bile acid research at the host-microbe interface has primarily been directed toward effects on host metabolism. The aim of this work was to investigate the effect of changes in gut microbial bile acid metabolism on the solubilization capacity of bile salt micelles and consequently intraluminal drug solubility. First, the impact of bile acid metabolism, mediated in vivo by the microbial enzymes bile salt hydrolase (BSH) and 7α-dehydroxylase, on drug solubility was assessed by comparing the solubilization capacity of (a) conjugated vs deconjugated and (b) primary vs secondary bile salts. A series of poorly water-soluble drugs (PWSDs) were selected as model solutes on the basis of an increased tendency to associate with bile micelles. Subsequently, PWSD solubility and dissolution was evaluated in conventional biorelevant simulated intestinal fluid containing host-derived bile acids, as well as in media modified to contain microbial bile acid metabolites. The findings suggest that deconjugation of the bile acid steroidal core, as dictated by BSH activity, influences micellar solubilization capacity for some PWSDs; however, these differences appear to be relatively minor. In contrast, the extent of bile acid hydroxylation, regulated by microbial 7α-dehydroxylase, was found to significantly affect the solubilization capacity of bile salt micelles for all nine drugs studied (p < 0.05). Subsequent investigations in biorelevant media containing either the trihydroxy bile salt sodium taurocholate (TCA) or the dihydroxy bile salt sodium taurodeoxycholate (TDCA) revealed altered drug solubility and dissolution. Observed differences in biorelevant media appeared to be both drug- and amphiphile (bile salt/lecithin) concentration-dependent. Our studies herein indicate that bile acid modifications occurring at the host-microbe interface could lead to alterations in the capacity of intestinal bile salt micelles to solubilize drugs, providing impetus to consider the gut microbiota in the drug absorption process. In the clinical setting, disruption of the gut microbial ecosystem, through disease or antibiotic treatment, could transform the bile acid pool with potential implications for drug absorption and bioavailability.

In Vitro Bile-Acid-Binding of Whole vs. Pearled Wheat Grain

USDA-ARS?s Scientific Manuscript database

Health benefits of consuming whole grains help reduce the risk of heart disease, stroke and cancer. The USDA Food Guide pyramid and dietary guidelines recommend the consumption of 6-10 oz of grain products daily and one-half of that is desired to be containing whole grains (2005). Whole grains con...

Bile acid malabsorption investigated by selenium-75-homocholic acid taurine ((75)SeHCAT) scans: causes and treatment responses to cholestyramine in 298 patients with chronic watery diarrhoea.

PubMed

Borghede, Märta K; Schlütter, Jacob M; Agnholt, Jørgen S; Christensen, Lisbet A; Gormsen, Lars C; Dahlerup, Jens F

2011-12-01

The liver produces and secretes bile acids into the small intestine. In the small intestine, most of the bile acids are absorbed in the distal ileum with portal vein transportation back to the liver and resecretion (enterohepatic recycling). Increased spillover of bile acids from the small intestine into the colon (bile acid malabsorption) may affect the secretion of colonic water and electrolytes and result in watery diarrhoea. The aim of this study was to investigate the frequency of bile acid malabsorption and treatment responses to cholestyramine with (75)SeHCAT scanning among patients suffering from chronic watery diarrhoea. This was a retrospective study that included all patients who received a (75)SeHCAT scan over a five-year period (2004-2009). In total, 298 patients (198 females, 100 men) with a median age of 42 years (range 16-82 years) were investigated. Bile acid malabsorption ((75)SeHCAT retention<15% after seven days) was identified in 201 patients (68%, 95% confidence interval (CI): 62%-73%). Bile acid malabsorption due to ileal dysfunction (Type I) was found in 77 patients, idiopathic bile acid malabsorption (Type II) was found in 68 patients and 56 patients with other conditions had bile acid malabsorption (Type III). Of the 150 patients who were able to take cholestyramine continuously, 108 patients (71%, CI: 63%-78%) reported a positive effect on their bowel habits. Bile acid malabsorption is a frequent problem in patients with chronic watery diarrhoea. Treatment with bile acid binders was effective regardless of type and severity. Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Interaction of Gut Microbiota with Bile Acid Metabolism and its Influence on Disease States

PubMed Central

Staley, Christopher; Weingarden, Alexa R.

2016-01-01

Primary bile acids serve important roles in cholesterol metabolism, lipid digestion, host-microbe interactions, and regulatory pathways in the human host. While most bile acids are reabsorbed and recycled via enterohepatic cycling, ~5% serve as substrates for bacterial biotransformation in the colon. Enzymes involved in various transformations have been characterized from cultured gut bacteria and reveal taxa-specific distribution. More recently, bioinformatic approaches have revealed greater diversity in isoforms of these enzymes, and the microbial species in which they are found. Thus, the functional roles played by the bile acid-transforming gut microbiota and the distribution of resulting secondary bile acids, in the bile acid pool, may be profoundly affected by microbial community structure and function. Bile acids and the composition of the bile acid pool have historically been hypothesized to be associated with several disease states, including recurrent Clostridium difficile infection, inflammatory bowel diseases, metabolic syndrome, and several cancers. Recently, however, emphasis has been placed on how microbial communities in the dysbiotic gut may alter the bile acid pool to potentially cause or mitigate disease onset. This review highlights the current understanding of the interactions between the gut microbial community, bile acid biotransformation, and disease states, and addresses future directions to better understand these complex associations. PMID:27888332

Role of AMACR (α-methylacyl-CoA racemase) and MFE-1 (peroxisomal multifunctional enzyme-1) in bile acid synthesis in mice.

PubMed

Autio, Kaija J; Schmitz, Werner; Nair, Remya R; Selkälä, Eija M; Sormunen, Raija T; Miinalainen, Ilkka J; Crick, Peter J; Wang, Yuqin; Griffiths, William J; Reddy, Janardan K; Baes, Myriam; Hiltunen, J Kalervo

2014-07-01

Cholesterol is catabolized to bile acids by peroxisomal β-oxidation in which the side chain of C27-bile acid intermediates is shortened by three carbon atoms to form mature C24-bile acids. Knockout mouse models deficient in AMACR (α-methylacyl-CoA racemase) or MFE-2 (peroxisomal multifunctional enzyme type 2), in which this β-oxidation pathway is prevented, display a residual C24-bile acid pool which, although greatly reduced, implies the existence of alternative pathways of bile acid synthesis. One alternative pathway could involve Mfe-1 (peroxisomal multifunctional enzyme type 1) either with or without Amacr. To test this hypothesis, we generated a double knockout mouse model lacking both Amacr and Mfe-1 activities and studied the bile acid profiles in wild-type, Mfe-1 and Amacr single knockout mouse line and Mfe-1 and Amacr double knockout mouse lines. The total bile acid pool was decreased in Mfe-1-/- mice compared with wild-type and the levels of mature C24-bile acids were reduced in the double knockout mice when compared with Amacr-deficient mice. These results indicate that Mfe-1 can contribute to the synthesis of mature bile acids in both Amacr-dependent and Amacr-independent pathways.

Fatty acid bile acid conjugates (FABACs)—New molecules for the prevention of cholesterol crystallisation in bile

PubMed Central

Gilat, T; Somjen, G; Mazur, Y; Leikin-Frenkel, A; Rosenberg, R; Halpern, Z; Konikoff, F.

2001-01-01

BACKGROUND—Cholesterol gall stones are a frequent disease for which at present surgery is the usual therapy. Despite the importance of bile acids it has become evident that phospholipids are the main cholesterol solubilisers in bile. Even phospholipid components, such as fatty acids, have anticrystallising activity.
AIM—To synthesise fatty acid bile acid conjugates (FABACs) and study their effects on cholesterol crystallisation in bile in vitro and in vivo.
METHODS—FABACs were prepared by conjugation of cholic acid at position 3 with saturated fatty acids of variable chain length using an amide bond. Cholesterol crystallisation and its kinetics (crystal observation time, crystal mass) were studied in model bile, pooled enriched human bile, and fresh human bile using FABACs with saturated fatty acids of varying chain length (C-6 to C-22). Absorption of FABACs into blood and bile was tested in hamsters. Prevention of biliary cholesterol crystallisation in vivo was tested in hamsters and inbred mice.
RESULTS—FABACs strongly inhibited cholesterol crystallisation in model as well as native bile. The FABACs with longer acyl chains (C-16 to C-22) were more effective. At a concentration of 5 mM, FABACs almost completely inhibited cholesterol crystallisation in fresh human bile for 21 days. FABACs were absorbed and found in both portal and heart blood of hamsters. Levels in bile were 2-3 times higher than in blood, indicating active secretion. Appreciable levels were found in the systemic circulation 24-48 hours after a single administration. Ingested FABACs completely prevented the formation of cholesterol crystals in the gall bladders of hamsters and mice fed a lithogenic diet.
CONCLUSIONS—FABACs are potent inhibitors of cholesterol crystallisation in bile. They are absorbed and secreted into bile and prevent the earliest step of cholesterol gall stone formation in animals. These compounds may be of potential use in cholesterol gall stone disease in humans.


Keywords: gall stones; bile; phospholipids; cholesterol crystallisation; fatty acid bile acid conjugates PMID:11115826

Mechanisms of bile acid mediated inflammation in the liver.

PubMed

Li, Man; Cai, Shi-Ying; Boyer, James L

2017-08-01

Bile acids are synthesized in the liver and are the major component in bile. Impaired bile flow leads to cholestasis that is characterized by elevated levels of bile acid in the liver and serum, followed by hepatocyte and biliary injury. Although the causes of cholestasis have been extensively studied, the molecular mechanisms as to how bile acids initiate liver injury remain controversial. In this chapter, we summarize recent advances in the pathogenesis of bile acid induced liver injury. These include bile acid signaling pathways in hepatocytes as well as the response of cholangiocytes and innate immune cells in the liver in both patients with cholestasis and cholestatic animal models. We focus on how bile acids trigger the production of molecular mediators of neutrophil recruitment and the role of the inflammatory response in this pathological process. These advances point to a number of novel targets where drugs might be judged to be effective therapies for cholestatic liver injury. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rat Liver Canalicular Membrane Vesicles Contain an ATP-Dependent Bile Acid Transport System

NASA Astrophysics Data System (ADS)

Nishida, Toshirou; Gatmaitan, Zenaida; Che, Mingxin; Arias, Irwin M.

1991-08-01

The secretion of bile by the liver is primarily determined by the ability of the hepatocyte to transport bile acids into the bile canaliculus. A carrier-mediated process for the transport of taurocholate, the major bile acid in humans and rats, was previously demonstrated in canalicular membrane vesicles from rat liver. This process is driven by an outside-positive membrane potential that is, however, insufficient to explain the large bile acid concentration gradient between the hepatocyte and bile. In this study, we describe an ATP-dependent transport system for taurocholate in inside-out canalicular membrane vesicles from rat liver. The transport system is saturable, temperature-dependent, osmotically sensitive, specifically requires ATP, and does not function in sinusoidal membrane vesicles and right side-out canalicular membrane vesicles. Transport was inhibited by other bile acids but not by substrates for the previously demonstrated ATP-dependent canalicular transport systems for organic cations or nonbile acid organic anions. Defects in ATP-dependent canalicular transport of bile acids may contribute to reduced bile secretion (cholestasis) in various developmental, inheritable, and acquired disorders.

Organochloride pesticides modulated gut microbiota and influenced bile acid metabolism in mice.

PubMed

Liu, Qian; Shao, Wentao; Zhang, Chunlan; Xu, Cheng; Wang, Qihan; Liu, Hui; Sun, Haidong; Jiang, Zhaoyan; Gu, Aihua

2017-07-01

Organochlorine pesticides (OCPs) can persistently accumulate in body and threaten human health. Bile acids and intestinal microbial metabolism have emerged as important signaling molecules in the host. However, knowledge on which intestinal microbiota and bile acids are modified by OCPs remains unclear. In this study, adult male C57BL/6 mice were exposed to p, p'-dichlorodiphenyldichloroethylene (p, p'-DDE) and β-hexachlorocyclohexane (β-HCH) for 8 weeks. The relative abundance and composition of various bacterial species were analyzed by 16S rRNA gene sequencing. Bile acid composition was analyzed by metabolomic analysis using UPLC-MS. The expression of genes involved in hepatic and enteric bile acids metabolism was measured by real-time PCR. Expression of genes in bile acids synthesis and transportation were measured in HepG2 cells incubated with p, p'-DDE and β-HCH. Our findings showed OCPs changed relative abundance and composition of intestinal microbiota, especially in enhanced Lactobacillus with bile salt hydrolase (BSH) activity. OCPs affected bile acid composition, enhanced hydrophobicity, decreased expression of genes on bile acid reabsorption in the terminal ileum and compensatory increased expression of genes on synthesis of bile acids in the liver. We demonstrated that chronic exposure of OCPs could impair intestinal microbiota; as a result, hepatic and enteric bile acid profiles and metabolism were influenced. The findings in this study draw our attention to the hazards of chronic OCPs exposure in modulating bile acid metabolism that might cause metabolic disorders and their potential to cause related diseases in human. Copyright © 2017 Elsevier Ltd. All rights reserved.

Altered Bile Acid Metabolome in Patients with Nonalcoholic Steatohepatitis.

PubMed

Ferslew, Brian C; Xie, Guoxiang; Johnston, Curtis K; Su, Mingming; Stewart, Paul W; Jia, Wei; Brouwer, Kim L R; Barritt, A Sidney

2015-11-01

The prevalence of nonalcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) is increasing at an alarming rate. The role of bile acids in the development and progression of NAFLD to NASH and cirrhosis is poorly understood. This study aimed to quantify the bile acid metabolome in healthy subjects and patients with non-cirrhotic NASH under fasting conditions and after a standardized meal. Liquid chromatography tandem mass spectroscopy was used to quantify 30 serum and 16 urinary bile acids from 15 healthy volunteers and 7 patients with biopsy-confirmed NASH. Bile acid concentrations were measured at two fasting and four post-prandial time points following a high-fat meal to induce gallbladder contraction and bile acid reabsorption from the intestine. Patients with NASH had significantly higher total serum bile acid concentrations than healthy subjects under fasting conditions (2.2- to 2.4-fold increase in NASH; NASH 2595-3549 µM and healthy 1171-1458 µM) and at all post-prandial time points (1.7- to 2.2-fold increase in NASH; NASH 4444-5898 µM and healthy 2634-2829 µM). These changes were driven by increased taurine- and glycine-conjugated primary and secondary bile acids. Patients with NASH exhibited greater variability in their fasting and post-prandial bile acid profile. Results indicate that patients with NASH have higher fasting and post-prandial exposure to bile acids, including the more hydrophobic and cytotoxic secondary species. Increased bile acid exposure may be involved in liver injury and the pathogenesis of NAFLD and NASH.

Recent advances in the understanding of bile acid malabsorption.

PubMed

Pattni, Sanjeev; Walters, Julian R F

2009-01-01

Bile acid malabsorption (BAM) is a syndrome of chronic watery diarrhoea with excess faecal bile acids. Disruption of the enterohepatic circulation of bile acids following surgical resection is a common cause of BAM. The condition is easily diagnosed by the selenium homocholic acid taurine (SeHCAT) test and responds to bile acid sequestrants. Idiopathic BAM (IBAM, primary bile acid diarrhoea) is the condition where no definitive cause for low SeHCAT retention can be identified. Review of PubMed and major journals. Evidence is accumulating that BAM is more prevalent than first thought. Management of chronic diarrhoea involves excluding secondary causes. Treatment of the condition is with bile acid binders. SeHCAT testing is not widely performed, limiting awareness of how common this condition can be. The underlying mechanism for IBAM has been unclear. Increasing awareness of the condition is important. Alternative mechanisms of IBAM have been suggested which involve an increased bile acid pool size and reduced negative feedback regulation of bile acid synthesis by FGF19. New sequestrants are available. Further research into the precise mechanism of IBAM is needed. Improvements in the recognition of the condition and optimization of treatment are required.

Comparison of Bile Acids and Acetaminophen Protein Adducts in Children and Adolescents with Acetaminophen Toxicity.

PubMed

James, Laura; Yan, Ke; Pence, Lisa; Simpson, Pippa; Bhattacharyya, Sudeepa; Gill, Pritmohinder; Letzig, Lynda; Kearns, Gregory; Beger, Richard

2015-01-01

Metabolomics approaches have enabled the study of new mechanisms of liver injury in experimental models of drug toxicity. Disruption of bile acid homeostasis is a known mechanism of drug induced liver injury. The relationship of individual bile acids to indicators of oxidative drug metabolism (acetaminophen protein adducts) and liver injury was examined in children with acetaminophen overdose, hospitalized children with low dose exposure to acetaminophen, and children with no recent exposure to acetaminophen. Nine bile acids were quantified through targeted metabolomic analysis in the serum samples of the three groups. Bile acids were compared to serum levels of acetaminophen protein adducts and alanine aminotransferase. Glycodeoxycholic acid, taurodeoxycholic acid, and glycochenodeoxycholic acid were significantly increased in children with acetaminophen overdose compared to healthy controls. Among patients with acetaminophen overdose, bile acids were higher in subjects with acetaminophen protein adduct values > 1.0 nmol/mL and modest correlations were noted for three bile acids and acetaminophen protein adducts as follows: taurodeoxycholic acid (R=0.604; p<0.001), glycodeoxycholic acid (R=0.581; p<0.001), and glycochenodeoxycholic acid (R=0.571; p<0.001). Variability in bile acids was greater among hospitalized children receiving low doses of acetaminophen than in healthy children with no recent acetaminophen exposure. Compared to bile acids, acetaminophen protein adducts more accurately discriminated among children with acetaminophen overdose, children with low dose exposure to acetaminophen, and healthy control subjects. In children with acetaminophen overdose, elevations of conjugated bile acids were associated with specific indicators of acetaminophen metabolism and non-specific indicators of liver injury.

History of hepatic bile formation: old problems, new approaches.

PubMed

Javitt, Norman B

2014-12-01

Studies of hepatic bile formation reported in 1958 established that it was an osmotically generated water flow. Intravenous infusion of sodium taurocholate established a high correlation between hepatic bile flow and bile acid excretion. Secretin, a hormone that stimulates bicarbonate secretion, was also found to increase hepatic bile flow. The sources of the water entering the biliary system with these two stimuli were differentiated by the use of mannitol. An increase in its excretion parallels the increase in bile flow in response to bile acids but not secretin, which led to a quantitative distinction between canalicular and ductular water flow. The finding of aquaglyceroporin-9 in the basolateral surface of the hepatocyte accounted for the rapid entry of mannitol into hepatocytes and its exclusion from water movement in the ductules where aquaporin-1 is present. Electron microscopy demonstrated that bile acids generate the formation of vesicles that contain lecithin and cholesterol after their receptor-mediated canalicular transport. Biophysical studies established that the osmotic effect of bile acids varies with their concentration and also with the proportion of mono-, di-, and trihydroxy bile acids and provides a basis for understanding their physiological effects. Because of the varying osmotic effect of bile acids, it is difficult to quantify bile acid independent flow generated by other solutes, such as glutathione, which enters the biliary system. Monohydroxy bile acids, by markedly increasing aggregation number, severely reduce water flow. Developing biomarkers for the noninvasive assessment of normal hepatic bile flow remains an elusive goal that merits further study. Copyright © 2014 The American Physiological Society.

Ursodeoxycholic Acid and Its Taurine- or Glycine-Conjugated Species Reduce Colitogenic Dysbiosis and Equally Suppress Experimental Colitis in Mice

PubMed Central

Van den Bossche, Lien; Hindryckx, Pieter; Devisscher, Lindsey; Devriese, Sarah; Van Welden, Sophie; Holvoet, Tom; Vilchez-Vargas, Ramiro; Vital, Marius; Pieper, Dietmar H.; Vanden Bussche, Julie; Vanhaecke, Lynn; Van de Wiele, Tom; De Vos, Martine

2017-01-01

ABSTRACT The promising results seen in studies of secondary bile acids in experimental colitis suggest that they may represent an attractive and safe class of drugs for the treatment of inflammatory bowel diseases (IBD). However, the exact mechanism by which bile acid therapy confers protection from colitogenesis is currently unknown. Since the gut microbiota plays a crucial role in the pathogenesis of IBD, and exogenous bile acid administration may affect the community structure of the microbiota, we examined the impact of the secondary bile acid ursodeoxycholic acid (UDCA) and its taurine or glycine conjugates on the fecal microbial community structure during experimental colitis. Daily oral administration of UDCA, tauroursodeoxycholic acid (TUDCA), or glycoursodeoxycholic acid (GUDCA) equally lowered the severity of dextran sodium sulfate-induced colitis in mice, as evidenced by reduced body weight loss, colonic shortening, and expression of inflammatory cytokines. Illumina sequencing demonstrated that bile acid therapy during colitis did not restore fecal bacterial richness and diversity. However, bile acid therapy normalized the colitis-associated increased ratio of Firmicutes to Bacteroidetes. Interestingly, administration of bile acids prevented the loss of Clostridium cluster XIVa and increased the abundance of Akkermansia muciniphila, bacterial species known to be particularly decreased in IBD patients. We conclude that UDCA, which is an FDA-approved drug for cholestatic liver disorders, could be an attractive treatment option to reduce dysbiosis and ameliorate inflammation in human IBD. IMPORTANCE Secondary bile acids are emerging as attractive candidates for the treatment of inflammatory bowel disease. Although bile acids may affect the intestinal microbial community structure, which significantly contributes to the course of these inflammatory disorders, the impact of bile acid therapy on the fecal microbiota during colitis has not yet been considered. Here, we studied the alterations in the fecal microbial abundance in colitic mice following the administration of secondary bile acids. Our results show that secondary bile acids reduce the severity of colitis and ameliorate colitis-associated fecal dysbiosis at the phylum level. This study indicates that secondary bile acids might act as a safe and effective drug for inflammatory bowel disease. PMID:28115375

Ursodeoxycholic Acid and Its Taurine- or Glycine-Conjugated Species Reduce Colitogenic Dysbiosis and Equally Suppress Experimental Colitis in Mice.

PubMed

Van den Bossche, Lien; Hindryckx, Pieter; Devisscher, Lindsey; Devriese, Sarah; Van Welden, Sophie; Holvoet, Tom; Vilchez-Vargas, Ramiro; Vital, Marius; Pieper, Dietmar H; Vanden Bussche, Julie; Vanhaecke, Lynn; Van de Wiele, Tom; De Vos, Martine; Laukens, Debby

2017-04-01

The promising results seen in studies of secondary bile acids in experimental colitis suggest that they may represent an attractive and safe class of drugs for the treatment of inflammatory bowel diseases (IBD). However, the exact mechanism by which bile acid therapy confers protection from colitogenesis is currently unknown. Since the gut microbiota plays a crucial role in the pathogenesis of IBD, and exogenous bile acid administration may affect the community structure of the microbiota, we examined the impact of the secondary bile acid ursodeoxycholic acid (UDCA) and its taurine or glycine conjugates on the fecal microbial community structure during experimental colitis. Daily oral administration of UDCA, tauroursodeoxycholic acid (TUDCA), or glycoursodeoxycholic acid (GUDCA) equally lowered the severity of dextran sodium sulfate-induced colitis in mice, as evidenced by reduced body weight loss, colonic shortening, and expression of inflammatory cytokines. Illumina sequencing demonstrated that bile acid therapy during colitis did not restore fecal bacterial richness and diversity. However, bile acid therapy normalized the colitis-associated increased ratio of Firmicutes to Bacteroidetes Interestingly, administration of bile acids prevented the loss of Clostridium cluster XIVa and increased the abundance of Akkermansia muciniphila , bacterial species known to be particularly decreased in IBD patients. We conclude that UDCA, which is an FDA-approved drug for cholestatic liver disorders, could be an attractive treatment option to reduce dysbiosis and ameliorate inflammation in human IBD. IMPORTANCE Secondary bile acids are emerging as attractive candidates for the treatment of inflammatory bowel disease. Although bile acids may affect the intestinal microbial community structure, which significantly contributes to the course of these inflammatory disorders, the impact of bile acid therapy on the fecal microbiota during colitis has not yet been considered. Here, we studied the alterations in the fecal microbial abundance in colitic mice following the administration of secondary bile acids. Our results show that secondary bile acids reduce the severity of colitis and ameliorate colitis-associated fecal dysbiosis at the phylum level. This study indicates that secondary bile acids might act as a safe and effective drug for inflammatory bowel disease. Copyright © 2017 American Society for Microbiology.

Obeticholic acid for severe bile acid diarrhea with intestinal failure: A case report and review of the literature

PubMed Central

Hvas, Christian Lodberg; Ott, Peter; Paine, Peter; Lal, Simon; Jørgensen, Søren Peter; Dahlerup, Jens Frederik

2018-01-01

Bile acid diarrhea results from excessive amounts of bile acids entering the colon due to hepatic overexcretion of bile acids or bile acid malabsorption in the terminal ileum. The main therapies include bile acid sequestrants, such as colestyramine and colesevelam, which may be given in combination with the opioid receptor agonist loperamide. Some patients are refractory to conventional treatments. We report the use of the farnesoid X receptor agonist obeticholic acid in a patient with refractory bile acid diarrhea and subsequent intestinal failure. A 32-year-old woman with quiescent colonic Crohn’s disease and a normal terminal ileum had been diagnosed with severe bile acid malabsorption and complained of watery diarrhea and fatigue. The diarrhea resulted in hypokalemia and sodium depletion that made her dependent on twice weekly intravenous fluid and electrolyte infusions. Conventional therapies with colestyramine, colesevelam, and loperamide had no effect. Second-line antisecretory therapies with pantoprazole, liraglutide, and octreotide also failed. Third-line treatment with obeticholic acid reduced the number of stools from an average of 13 to an average of 7 per 24 h and improved the patient’s quality of life. The fluid and electrolyte balances normalized. The effect was sustained during follow-up for 6 mo with treatment at a daily dosage of 25 mg. The diarrhea worsened shortly after cessation of obeticholic acid. This case report supports the initial report that obeticholic acid may reduce bile acid production and improve symptoms in patients with bile acid diarrhea. PMID:29881241

Use of D(acid)-, D(bile)-, z(acid)-, and z(bile)-values in evaluating Bifidobacteria with regard to stomach pH and bile salt sensitivity.

PubMed

Jia, Li; Shigwedha, Nditange; Mwandemele, Osmund D

2010-01-01

The survival of bifidobacteria in simulated conditions of the gastrointestinal (GI) tract was studied based on the D- and z-value concept. Some Bifidobacterium spp. are probiotics that improve microbial balance in the human GI tract. Because they are sensitive to low pH and bile salt concentrations, their viability in the GI tract is limited. The D- and z-value approach was therefore adopted as a result of observing constant log-cell reduction (90%) when Bifidobacterium spp. were exposed to these 2 different stressing factors. Survivals of one strain each or 4 species of Bifidobacterium was studied at pH between 3.0 and 4.5 and in ox-bile between 0.15% and 0.60% for times up to 41 h. From the D(acid)- and D(bile)-values, the order of resistance to acid and bile was B. bifidum > B. infantis > B. longum > B. adolescentis. While the former 3 strains retained high cell viability at pH 3.5 (>5.5 log CFU/mL after 5 h) and at elevated bile salt concentration of 0.6% (>4.5 log CFU/mL after 3 h), B. adolescentis was less resistant (<3.4 log CFU/mL). The z(acid)- and z(bile)-values calculated from the D(acid)- and D(bile)-values ranged from 1.11 to 1.55 pH units and 0.40% to 0.49%, respectively. The results suggest that the D(acid)-, D(bile)-, z(acid)-, and z(bile)-value approach could be more appropriate than the screening and selection method in evaluating survival of probiotic bacteria, and in measuring their tolerance or resistance to gastric acidity and the associated bile salt concentration in the small intestine. The evaluation of the tolerance of bifidobacteria to bile salts and low pH has been made possible by use of D- and z-value concept. The calculated z(acid)- and z(bile)-values were all fairly similar for the strains used and suggest the effect of increasing the bile salt concentration or decreasing the pH on the D(acid)- and D(bile)-values. This approach would be useful for predicting the suitability of bifidobacteria and other lactic acid bacteria (LAB) as probiotics for use in real-life situations.

Rethinking the bile acid/gut microbiome axis in cancer

PubMed Central

Phelan, John P.; Reen, F. Jerry; Caparros-Martin, Jose A.; O'Connor, Rosemary; O'Gara, Fergal

2017-01-01

Dietary factors, probiotic agents, aging and antibiotics/medicines impact on gut microbiome composition leading to disturbances in localised microbial populations. The impact can be profound and underlies a plethora of human disorders, including the focus of this review; cancer. Compromised microbiome populations can alter bile acid signalling and produce distinct pathophysiological bile acid profiles. These in turn have been associated with cancer development and progression. Exposure to high levels of bile acids, combined with localised molecular/genome instability leads to the acquisition of bile mediated neoplastic alterations, generating apoptotic resistant proliferation phenotypes. However, in recent years, several studies have emerged advocating the therapeutic benefits of bile acid signalling in suppressing molecular and phenotypic hallmarks of cancer progression. These studies suggest that in some instances, bile acids may reduce cancer phenotypic effects, thereby limiting metastatic potential. In this review, we contextualise the current state of the art to propose that the bile acid/gut microbiome axis can influence cancer progression to the extent that classical in vitro cancer hallmarks of malignancy (cell invasion, cell migration, clonogenicity, and cell adhesion) are significantly reduced. We readily acknowledge the existence of a bile acid/gut microbiome axis in cancer initiation, however, in light of recent advances, we focus exclusively on the role of bile acids as potentially beneficial molecules in suppressing cancer progression. Finally, we theorise that suppressing aggressive malignant phenotypes through bile acid/gut microbiome axis modulation could uncover new and innovative disease management strategies for managing cancers in vulnerable cohorts. PMID:29383197

Sevelamer Improves Steatohepatitis, Inhibits Liver and Intestinal Farnesoid X Receptor (FXR), and Reverses Innate Immune Dysregulation in a Mouse Model of Non-alcoholic Fatty Liver Disease.

PubMed

McGettigan, Brett M; McMahan, Rachel H; Luo, Yuhuan; Wang, Xiaoxin X; Orlicky, David J; Porsche, Cara; Levi, Moshe; Rosen, Hugo R

2016-10-28

Bile acid sequestrants are synthetic polymers that bind bile acids in the gut and are used to treat dyslipidemia and hyperphosphatemia. Recently, these agents have been reported to lower blood glucose and increase insulin sensitivity by altering bile acid signaling pathways. In this study, we assessed the efficacy of sevelamer in treating mice with non-alcoholic fatty liver disease (NAFLD). We also analyzed how sevelamer alters inflammation and bile acid signaling in NAFLD livers. Mice were fed a low-fat or Western diet for 12 weeks followed by a diet-plus-sevelamer regimen for 2 or 12 weeks. At the end of treatment, disease severity was assessed, hepatic leukocyte populations were examined, and expression of genes involved in farnesoid X receptor (FXR) signaling in the liver and intestine was analyzed. Sevelamer treatment significantly reduced liver steatosis and lobular inflammation. Sevelamer-treated NAFLD livers had notably fewer pro-inflammatory infiltrating macrophages and a significantly greater fraction of alternatively activated Kupffer cells compared with controls. Expression of genes involved in FXR signaling in the liver and intestine was significantly altered in mice with NAFLD as well as in those treated with sevelamer. In a mouse model of NAFLD, sevelamer improved disease and counteracted innate immune cell dysregulation in the liver. This study also revealed a dysregulation of FXR signaling in the liver and intestine of NAFLD mice that was counteracted by sevelamer treatment. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

FXR signaling in the enterohepatic system

PubMed Central

Matsubara, Tsutomu; Li, Fei; Gonzalez, Frank J.

2012-01-01

Enterohepatic circulation serves to capture bile acids and other steroid metabolites produced in the liver and secreted to the intestine, for reabsorption back into the circulation and reuptake to the liver. This process is under tight regulation by nuclear receptor signaling. Bile acids, produced from cholesterol, can alter gene expression in the liver and small intestine via activating the nuclear receptors farnesoid X receptor (FXR; NR1H4), pregnane X receptor (PXR; NR1I2), vitamin D receptor (VDR; NR1I1), G protein coupled receptor TGR5, and other cell signaling pathways (JNK1/2, AKT and ERK1/2). Among these controls, FXR is known to be a major bile acid-responsive ligand-activated transcription factor and a crucial control element for maintaining bile acid homeostasis. FXR has a high affinity for several major endogenous bile acids, notably cholic acid, deoxycholic acid, chenodeoxycholic acid, and lithocholic acid. By responding to excess bile acids, FXR is a bridge between the liver and small intestine to control bile acid levels and regulate bile acid synthesis and enterohepatic flow. FXR is highly expressed in the liver and gut, relative to other tissues, and contributes to the maintenance of cholesterol/bile acid homeostasis by regulating a variety of metabolic enzymes and transporters. FXR activation also affects lipid and glucose metabolism, and can influence drug metabolism. PMID:22609541

Role of the Intestinal Bile Acid Transporters in Bile Acid and Drug Disposition

PubMed Central

Dawson, Paul A.

2011-01-01

Membrane transporters expressed by the hepatocyte and enterocyte play critical roles in maintaining the enterohepatic circulation of bile acids, an effective recycling and conservation mechanism that largely restricts these potentially cytotoxic detergents to the intestinal and hepatobiliary compartments. In doing so, the hepatic and enterocyte transport systems ensure a continuous supply of bile acids to be used repeatedly during the digestion of multiple meals throughout the day. Absorption of bile acids from the intestinal lumen and export into the portal circulation is mediated by a series of transporters expressed on the enterocyte apical and basolateral membranes. The ileal apical sodium-dependent bile acid cotransporter (abbreviated ASBT; gene symbol, SLC10A2) is responsible for the initial uptake of bile acids across the enterocyte brush border membrane. The bile acids are then efficiently shuttled across the cell and exported across the basolateral membrane by the heteromeric Organic Solute Transporter, OSTα-OSTβ. This chapter briefly reviews the tissue expression, physiology, genetics, pathophysiology, and transport properties of the ASBT and OSTα-OSTα. In addition, the chapter discusses the relationship between the intestinal bile acid transporters and drug metabolism, including development of ASBT inhibitors as novel hypocholesterolemic or hepatoprotective agents, prodrug targeting of the ASBT to increase oral bioavailability, and involvement of the intestinal bile acid transporters in drug absorption and drug-drug interactions. PMID:21103970

Bile acid receptors link nutrient sensing to metabolic regulation

PubMed Central

Li, Jibiao; Li, Tiangang

2017-01-01

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease in Western populations. Non-alcoholic steatohepatitis (NASH) is a more debilitating form of NAFLD characterized by hepatocellular injury and inflammation, which significantly increase the risk of end-stage liver and cardiovascular diseases. Unfortunately, there are no available drug therapies for NASH. Bile acids are physiological detergent molecules that are synthesized from cholesterol exclusively in the hepatocytes. Bile acids circulate between the liver and intestine, where they are required for cholesterol solubilization in the bile and dietary fat emulsification in the gut. Bile acids also act as signaling molecules that regulate metabolic homeostasis and inflammatory processes. Many of these effects are mediated by the bile acid-activated nuclear receptor farnesoid X receptor (FXR) and the G protein-coupled receptor TGR5. Nutrient signaling regulates hepatic bile acid synthesis and circulating plasma bile acid concentrations, which in turn control metabolic homeostasis. The FXR agonist obeticholic acid has had beneficial effects on NASH in recent clinical trials. Preclinical studies have suggested that the TGR5 agonist and the FXR/TGR5 dual agonist are also potential therapies for metabolic liver diseases. Extensive studies in the past few decades have significantly improved our understanding of the metabolic regulatory function of bile acids, which has provided the molecular basis for developing promising bile acid-based therapeutic agents for NASH treatment. PMID:29098111

Ionene modified small polymeric beads

NASA Technical Reports Server (NTRS)

Rembaum, Alan (Inventor)

1977-01-01

Linear ionene polyquaternary cationic polymeric segments are bonded by means of the Menshutkin reaction (quaternization) to biocompatible, extremely small, porous particles containing halide or tertiary amine sites which are centers for attachment of the segments. The modified beads in the form of emulsions or suspensions offer a large, positively-charged surface area capable of irreversibly binding polyanions such as heparin, DNA, RNA or bile acids to remove them from solution or of reversibly binding monoanions such as penicillin, pesticides, sex attractants and the like for slow release from the suspension.

Analysis of ileal sodium/bile acid cotransporter and related nuclear receptor genes in a family with multiple cases of idiopathic bile acid malabsorption

PubMed Central

Montagnani, Marco; Abrahamsson, Anna; Gälman, Cecilia; Eggertsen, Gösta; Marschall, Hanns-Ulrich; Ravaioli, Elisa; Einarsson, Curt; Dawson, Paul A

2006-01-01

The etiology of most cases of idiopathic bile acid malabsorption (IBAM) is unknown. In this study, a Swedish family with bile acid malabsorption in three consecutive generations was screened for mutations in the ileal apical sodium-bile acid cotransporter gene (ASBT; gene symbol, SLC10A2) and in the genes for several of the nuclear receptors known to be important for ASBT expression: the farnesoid X receptor (FXR) and peroxisome proliferator activated receptor alpha (PPARα). The patients presented with a clinical history of idiopathic chronic watery diarrhea, which was responsive to cholestyramine treatment and consistent with IBAM. Bile acid absorption was determined using 75Se-homocholic acid taurine (SeHCAT); bile acid synthesis was estimated by measuring the plasma levels of 7α-hydroxy-4-cholesten-3-one (C4). The ASBT, FXR, and PPARα genes in the affected and unaffected family members were analyzed using single stranded conformation polymorphism (SSCP), denaturing HPLC, and direct sequencing. No ASBT mutations were identified and the ASBT gene did not segregate with the bile acid malabsorption phenotype. Similarly, no mutations or polymorphisms were identified in the FXR or PPARα genes associated with the bile acid malabsorption phenotype. These studies indicate that the intestinal bile acid malabsorption in these patients cannot be attributed to defects in ASBT. In the absence of apparent ileal disease, alternative explanations such as accelerated transit through the small intestine may be responsible for the IBAM. PMID:17171805

A new mechanism for bile acid diarrhea: defective feedback inhibition of bile acid biosynthesis.

PubMed

Walters, Julian R F; Tasleem, Ali M; Omer, Omer S; Brydon, W Gordon; Dew, Tracy; le Roux, Carel W

2009-11-01

Primary (idiopathic) bile acid malabsorption (BAM) is a common, yet underrecognized, chronic diarrheal syndrome. Diagnosis is difficult without selenium homocholic acid taurine (SeHCAT) testing. The diarrhea results from excess colonic bile acids, but the pathogenesis is unclear. Fibroblast growth factor 19 (FGF19), produced in the ileum in response to bile acid absorption, regulates hepatic bile acid synthesis. We proposed that FGF19 is involved in bile acid diarrhea and measured its levels in patients with BAM. Blood was collected from fasting patients with chronic diarrhea; BAM was diagnosed by SeHCAT. Serum FGF19 was measured by enzyme-linked immunosorbent assay. Serum 7alpha-hydroxy-4-cholesten-3-one (C4) was determined using high-performance liquid chromatography, to quantify bile acid synthesis. Data were compared between patients and subjects without diarrhea (controls). Samples were taken repeatedly after meals from several subjects. The median C4 level was significantly higher in patients with primary BAM than in controls (51 vs 18 ng/mL; P < .0001). The median FGF19 level was significantly lower in patients with BAM (120 vs 231 pg/mL; P < .0005). There was a significant inverse relationship between FGF19 and C4 levels (P < .0004). Low levels of FGF19 were also found in patients with postcholecystectomy and secondary bile acid diarrhea. Abnormal patterns of FGF19 levels were observed throughout the day in some patients with primary BAM. Patients with BAM have reduced serum FGF19 which may be useful in diagnosis. We propose a mechanism whereby impaired FGF19 feedback inhibition causes excessive bile acid synthesis that exceeds the normal capacity for ileal reabsorption, producing bile acid diarrhea.

Bile acids induce necrosis in pancreatic stellate cells dependent on calcium entry and sodium-driven bile uptake.

PubMed

Ferdek, Pawel E; Jakubowska, Monika A; Gerasimenko, Julia V; Gerasimenko, Oleg V; Petersen, Ole H

2016-11-01

Acute biliary pancreatitis is a sudden and severe condition initiated by bile reflux into the pancreas. Bile acids are known to induce Ca 2+ signals and necrosis in isolated pancreatic acinar cells but the effects of bile acids on stellate cells are unexplored. Here we show that cholate and taurocholate elicit more dramatic Ca 2+ signals and necrosis in stellate cells compared to the adjacent acinar cells in pancreatic lobules; whereas taurolithocholic acid 3-sulfate primarily affects acinar cells. Ca 2+ signals and necrosis are strongly dependent on extracellular Ca 2+ as well as Na + ; and Na + -dependent transport plays an important role in the overall bile acid uptake in pancreatic stellate cells. Bile acid-mediated pancreatic damage can be further escalated by bradykinin-induced signals in stellate cells and thus killing of stellate cells by bile acids might have important implications in acute biliary pancreatitis. Acute biliary pancreatitis, caused by bile reflux into the pancreas, is a serious condition characterised by premature activation of digestive enzymes within acinar cells, followed by necrosis and inflammation. Bile acids are known to induce pathological Ca 2+ signals and necrosis in acinar cells. However, bile acid-elicited signalling events in stellate cells remain unexplored. This is the first study to demonstrate the pathophysiological effects of bile acids on stellate cells in two experimental models: ex vivo (mouse pancreatic lobules) and in vitro (human cells). Sodium cholate and taurocholate induced cytosolic Ca 2+ elevations in stellate cells, larger than those elicited simultaneously in the neighbouring acinar cells. In contrast, taurolithocholic acid 3-sulfate (TLC-S), known to induce Ca 2+ oscillations in acinar cells, had only minor effects on stellate cells in lobules. The dependence of the Ca 2+ signals on extracellular Na + and the presence of sodium-taurocholate cotransporting polypeptide (NTCP) indicate a Na + -dependent bile acid uptake mechanism in stellate cells. Bile acid treatment caused necrosis predominantly in stellate cells, which was abolished by removal of extracellular Ca 2+ and significantly reduced in the absence of Na + , showing that bile-dependent cell death was a downstream event of Ca 2+ signals. Finally, combined application of TLC-S and the inflammatory mediator bradykinin caused more extensive necrosis in both stellate and acinar cells than TLC-S alone. Our findings shed new light on the mechanism by which bile acids promote pancreatic pathology. This involves not only signalling in acinar cells but also in stellate cells. © 2016 The Authors The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Intestinal transport and metabolism of bile acids

PubMed Central

Dawson, Paul A.; Karpen, Saul J.

2015-01-01

In addition to their classical roles as detergents to aid in the process of digestion, bile acids have been identified as important signaling molecules that function through various nuclear and G protein-coupled receptors to regulate a myriad of cellular and molecular functions across both metabolic and nonmetabolic pathways. Signaling via these pathways will vary depending on the tissue and the concentration and chemical structure of the bile acid species. Important determinants of the size and composition of the bile acid pool are their efficient enterohepatic recirculation, their host and microbial metabolism, and the homeostatic feedback mechanisms connecting hepatocytes, enterocytes, and the luminal microbiota. This review focuses on the mammalian intestine, discussing the physiology of bile acid transport, the metabolism of bile acids in the gut, and new developments in our understanding of how intestinal metabolism, particularly by the gut microbiota, affects bile acid signaling. PMID:25210150

Bile Routing Modification Reproduces Key Features of Gastric Bypass in Rat.

PubMed

Goncalves, Daisy; Barataud, Aude; De Vadder, Filipe; Vinera, Jennifer; Zitoun, Carine; Duchampt, Adeline; Mithieux, Gilles

2015-12-01

To evaluate the role of bile routing modification on the beneficial effects of gastric bypass surgery on glucose and energy metabolism. Gastric bypass surgery (GBP) promotes early improvements in glucose and energy homeostasis in obese diabetic patients. A suggested mechanism associates a decrease in hepatic glucose production to an enhanced intestinal gluconeogenesis. Moreover, plasma bile acids are elevated after GBP and bile acids are inhibitors of gluconeogenesis. In male Sprague-Dawley rats, we performed bile diversions from the bile duct to the midjejunum or the mid-ileum to match the modified bile delivery in the gut occurring in GBP. Body weight, food intake, glucose tolerance, insulin sensitivity, and food preference were analyzed. The expression of gluconeogenesis genes was evaluated in both the liver and the intestine. Bile diversions mimicking GBP promote an increase in plasma bile acids and a marked improvement in glucose control. Bile bioavailability modification is causal because a bile acid sequestrant suppresses the beneficial effects of bile diversions on glucose control. In agreement with the inhibitory role of bile acids on gluconeogenesis, bile diversions promote a blunting in hepatic glucose production, whereas intestinal gluconeogenesis is increased in the gut segments devoid of bile. In rats fed a high-fat-high-sucrose diet, bile diversions improve glucose control and dramatically decrease food intake because of an acquired disinterest in fatty food. This study shows that bile routing modification is a key mechanistic feature in the beneficial outcomes of GBP.

Bile Routing Modification Reproduces Key Features of Gastric Bypass in Rat

PubMed Central

Goncalves, Daisy; Barataud, Aude; De Vadder, Filipe; Vinera, Jennifer; Zitoun, Carine; Duchampt, Adeline; Mithieux, Gilles

2015-01-01

STRUCTURED ABSTRACT Objective To evaluate the role of bile routing modification on the beneficial effects of gastric bypass surgery on glucose and energy metabolism. Summary background data Gastric bypass surgery (GBP) promotes early improvements in glucose and energy homeostasis in obese diabetic patients. A suggested mechanism associates a decrease in hepatic glucose production (HGP) to an enhanced intestinal gluconeogenesis (IGN). Moreover, plasma bile acids are elevated after GBP and bile acids are inhibitors of gluconeogenesis. Methods In male Sprague-Dawley rats, we performed bile diversions from the bile duct to the mid-jejunum or the mid-ileum to match the modified bile delivery in the gut occurring in GBP. Body weight, food intake, glucose tolerance, insulin sensitivity and food preference were analyzed. The expression of gluconeogenesis genes was evaluated in both the liver and the intestine. Results Bile diversions mimicking GBP promote an increase in plasma bile acids and a marked improvement in glucose control. Bile bioavailability modification is causal since a bile acid sequestrant suppresses the beneficial effects of bile diversions on glucose control. In agreement with the inhibitory role of bile acids on gluconeogenesis, bile diversions promote a blunting in HGP, whereas IGN is increased in the gut segments devoid of bile. In rats fed a high fat-high sucrose diet, bile diversions improve glucose control and dramatically decrease food intake due to an acquired disinterest in fatty food. Conclusion This study shows that bile routing modification is a key mechanistic feature in the beneficial outcomes of GBP. PMID:25575265

Serum 7 alpha-hydroxy-4-cholesten-3-one concentrations in the evaluation of bile acid malabsorption in patients with diarrhoea: correlation to SeHCAT test.

PubMed Central

Eusufzai, S; Axelson, M; Angelin, B; Einarsson, K

1993-01-01

The synthesis of bile acids is regulated by a homeostatic mechanism in which bile acids returning to the liver from the intestine inhibit their own synthesis. Serum concentrations of the bile acid intermediate 7 alpha-hydroxy-4-cholesten-3-one reflect the rate of bile acid synthesis whereas bile acid malabsorption can be determined by the SeHCAT test. This study was done to evaluate the correlation between the two tests in humans. Twenty eight patients with chronic diarrhoea were included in the study. Fasting serum was collected for the determination of 7 alpha-hydroxy-4-cholesten-3-one, and on the same day the gamma emitting bile acid analogue SeHCAT was given orally and its fractional catabolic rate assessed by repeated external counting over the upper abdomen during the next seven days. There was a highly significant positive correlation between the two tests (Rs = 0.80, p < 0.001). The results show a close relation between intestinal loss and hepatic synthesis of bile acids and imply that analysis of 7 alpha-hydroxy-4-cholesten-3-one in serum should now be evaluated as a possible convenient method for assessing bile acid malabsorption in patients with diarrhoea. PMID:8504974

Defining primary bile acid diarrhea: making the diagnosis and recognizing the disorder.

PubMed

Walters, Julian R F

2010-10-01

Chronic diarrhea due to bile acid malabsorption may be considered as contributing to the diagnosis when it results from secondary causes, such as ileal resection affecting the enterohepatic circulation. However, the primary form (also known as idiopathic bile acid malabsorption) is not well recognized as a common condition and patients are left undiagnosed. Primary bile acid diarrhea can be diagnosed by the nuclear medicine 75Se-homocholyltaurine (SeHCAT) test, although this is unavailable or underutilized in many settings. A systematic review suggests that approximately 30% of patients who would otherwise be diagnosed with diarrhea-predominant irritable bowel syndrome or functional diarrhea have abnormal SeHCAT retention. Serum 7α-hydroxy-4-cholesten-3-one can also be measured to show increased bile acid synthesis. The reasons for the lack of recognition of primary bile acid diarrhea are discussed, and these are compared with the other common cause of malabsorption, celiac disease. The lack of a clear pathophysiological mechanism has been a problem, but recent evidence suggests that impaired feedback control of hepatic bile acid synthesis by the ileal hormone FGF19 results in overproduction of bile acids. The identification of FGF19 as the central mechanism opens up new areas for development in the diagnosis and treatment of primary bile acid diarrhea.

Serum 7 alpha-hydroxy-4-cholesten-3-one concentrations in the evaluation of bile acid malabsorption in patients with diarrhoea: correlation to SeHCAT test.

PubMed

Eusufzai, S; Axelson, M; Angelin, B; Einarsson, K

1993-05-01

The synthesis of bile acids is regulated by a homeostatic mechanism in which bile acids returning to the liver from the intestine inhibit their own synthesis. Serum concentrations of the bile acid intermediate 7 alpha-hydroxy-4-cholesten-3-one reflect the rate of bile acid synthesis whereas bile acid malabsorption can be determined by the SeHCAT test. This study was done to evaluate the correlation between the two tests in humans. Twenty eight patients with chronic diarrhoea were included in the study. Fasting serum was collected for the determination of 7 alpha-hydroxy-4-cholesten-3-one, and on the same day the gamma emitting bile acid analogue SeHCAT was given orally and its fractional catabolic rate assessed by repeated external counting over the upper abdomen during the next seven days. There was a highly significant positive correlation between the two tests (Rs = 0.80, p < 0.001). The results show a close relation between intestinal loss and hepatic synthesis of bile acids and imply that analysis of 7 alpha-hydroxy-4-cholesten-3-one in serum should now be evaluated as a possible convenient method for assessing bile acid malabsorption in patients with diarrhoea.

Bile Acid Signaling Pathways from the Enterohepatic Circulation to the Central Nervous System

PubMed Central

Mertens, Kim L.; Kalsbeek, Andries; Soeters, Maarten R.; Eggink, Hannah M.

2017-01-01

Bile acids are best known as detergents involved in the digestion of lipids. In addition, new data in the last decade have shown that bile acids also function as gut hormones capable of influencing metabolic processes via receptors such as FXR (farnesoid X receptor) and TGR5 (Takeda G protein-coupled receptor 5). These effects of bile acids are not restricted to the gastrointestinal tract, but can affect different tissues throughout the organism. It is still unclear whether these effects also involve signaling of bile acids to the central nervous system (CNS). Bile acid signaling to the CNS encompasses both direct and indirect pathways. Bile acids can act directly in the brain via central FXR and TGR5 signaling. In addition, there are two indirect pathways that involve intermediate agents released upon interaction with bile acids receptors in the gut. Activation of intestinal FXR and TGR5 receptors can result in the release of fibroblast growth factor 19 (FGF19) and glucagon-like peptide 1 (GLP-1), both capable of signaling to the CNS. We conclude that when plasma bile acids levels are high all three pathways may contribute in signal transmission to the CNS. However, under normal physiological circumstances, the indirect pathway involving GLP-1 may evoke the most substantial effect in the brain. PMID:29163019

The Reversed Feto-Maternal Bile Acid Gradient in Intrahepatic Cholestasis of Pregnancy Is Corrected by Ursodeoxycholic Acid

PubMed Central

Geenes, Victoria; Lövgren-Sandblom, Anita; Benthin, Lisbet; Lawrance, Dominic; Chambers, Jenny; Gurung, Vinita; Thornton, Jim; Chappell, Lucy; Khan, Erum; Dixon, Peter; Marschall, Hanns-Ulrich; Williamson, Catherine

2014-01-01

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disorder associated with an increased risk of adverse fetal outcomes. It is characterised by raised maternal serum bile acids, which are believed to cause the adverse outcomes. ICP is commonly treated with ursodeoxycholic acid (UDCA). This study aimed to determine the fetal and maternal bile acid profiles in normal and ICP pregnancies, and to examine the effect of UDCA treatment. Matched maternal and umbilical cord serum samples were collected from untreated ICP (n = 18), UDCA-treated ICP (n = 46) and uncomplicated pregnancy (n = 15) cases at the time of delivery. Nineteen individual bile acids were measured using HPLC-MS/MS. Maternal and fetal serum bile acids are significantly raised in ICP compared with normal pregnancy (p = <0.0001 and <0.05, respectively), predominantly due to increased levels of conjugated cholic and chenodeoxycholic acid. There are no differences between the umbilical cord artery and cord vein levels of the major bile acid species. The feto-maternal gradient of bile acids is reversed in ICP. Treatment with UDCA significantly reduces serum bile acids in the maternal compartment (p = <0.0001), thereby reducing the feto-maternal transplacental gradient. UDCA-treatment does not cause a clinically important increase in lithocholic acid (LCA) concentrations. ICP is associated with significant quantitative and qualitative changes in the maternal and fetal bile acid pools. Treatment with UDCA reduces the level of bile acids in both compartments and reverses the qualitative changes. We have not found evidence to support the suggestion that UDCA treatment increases fetal LCA concentrations to deleterious levels. PMID:24421907

The reversed feto-maternal bile acid gradient in intrahepatic cholestasis of pregnancy is corrected by ursodeoxycholic acid.

PubMed

Geenes, Victoria; Lövgren-Sandblom, Anita; Benthin, Lisbet; Lawrance, Dominic; Chambers, Jenny; Gurung, Vinita; Thornton, Jim; Chappell, Lucy; Khan, Erum; Dixon, Peter; Marschall, Hanns-Ulrich; Williamson, Catherine

2014-01-01

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disorder associated with an increased risk of adverse fetal outcomes. It is characterised by raised maternal serum bile acids, which are believed to cause the adverse outcomes. ICP is commonly treated with ursodeoxycholic acid (UDCA). This study aimed to determine the fetal and maternal bile acid profiles in normal and ICP pregnancies, and to examine the effect of UDCA treatment. Matched maternal and umbilical cord serum samples were collected from untreated ICP (n = 18), UDCA-treated ICP (n = 46) and uncomplicated pregnancy (n = 15) cases at the time of delivery. Nineteen individual bile acids were measured using HPLC-MS/MS. Maternal and fetal serum bile acids are significantly raised in ICP compared with normal pregnancy (p = <0.0001 and <0.05, respectively), predominantly due to increased levels of conjugated cholic and chenodeoxycholic acid. There are no differences between the umbilical cord artery and cord vein levels of the major bile acid species. The feto-maternal gradient of bile acids is reversed in ICP. Treatment with UDCA significantly reduces serum bile acids in the maternal compartment (p = <0.0001), thereby reducing the feto-maternal transplacental gradient. UDCA-treatment does not cause a clinically important increase in lithocholic acid (LCA) concentrations. ICP is associated with significant quantitative and qualitative changes in the maternal and fetal bile acid pools. Treatment with UDCA reduces the level of bile acids in both compartments and reverses the qualitative changes. We have not found evidence to support the suggestion that UDCA treatment increases fetal LCA concentrations to deleterious levels.

Increased serum bile acid concentration following low-dose chronic administration of thioacetamide in rats, as evidenced by metabolomic analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeong, Eun Sook; Kim, Gabin; Shin, Ho Jung

A liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS)-based metabolomics approach was employed to identify endogenous metabolites as potential biomarkers for thioacetamide (TAA)-induced liver injury. TAA (10 and 30 mg/kg), a well-known hepatotoxic agent, was administered daily to male Sprague–Dawley (SD) rats for 28 days. We then conducted untargeted analyses of endogenous serum and liver metabolites. Partial least squares discriminant analysis (PLS-DA) was performed on serum and liver samples to evaluate metabolites associated with TAA-induced perturbation. TAA administration resulted in altered levels of bile acids, acyl carnitines, and phospholipids in serum and in the liver. We subsequently demonstrated and confirmed the occurrence ofmore » compromised bile acid homeostasis. TAA treatment significantly increased serum levels of conjugated bile acids in a dose-dependent manner, which correlated well with toxicity. However, hepatic levels of these metabolites were not substantially changed. Gene expression profiling showed that the hepatic mRNA levels of Ntcp, Bsep, and Oatp1b2 were significantly suppressed, whereas those of basolateral Mrp3 and Mrp4 were increased. Decreased levels of Ntcp, Oatp1b2, and Ostα proteins in the liver were confirmed by western blot analysis. These results suggest that serum bile acids might be increased due to the inhibition of bile acid enterohepatic circulation rather than increased endogenous bile acid synthesis. Moreover, serum bile acids are a good indicator of TAA-induced hepatotoxicity. - Highlights: • Endogenous metabolic profiles were assessed in rat after treatment of thioacetamide. • It significantly increased the levels of bile acids in serum but not in the liver. • Expression of the genes related to bile acid secretion and reuptake was decreased. • Increased serum bile acids result from block of enterohepatic circulation of bile acids.« less

Bile acid profiles over 5 years after gastric bypass and duodenal switch: results from a randomized clinical trial.

PubMed

Risstad, Hilde; Kristinsson, Jon A; Fagerland, Morten W; le Roux, Carel W; Birkeland, Kåre I; Gulseth, Hanne L; Thorsby, Per M; Vincent, Royce P; Engström, My; Olbers, Torsten; Mala, Tom

2017-09-01

Bile acids have been proposed as key mediators of the metabolic effects after bariatric surgery. Currently no reports on bile acid profiles after duodenal switch exist, and long-term data after gastric bypass are lacking. To investigate bile acid profiles up to 5 years after Roux-en-Y gastric bypass and biliopancreatic diversion with duodenal switch and to explore the relationship among bile acids and weight loss, lipid profile, and glucose metabolism. Two Scandinavian University Hospitals. We present data from a randomized clinical trial of 60 patients with body mass index 50-60 kg/m 2 operated with gastric bypass or duodenal switch. Repeated measurements of total and individual bile acids from fasting serum during 5 years after surgery were performed. Mean concentrations of total bile acids increased from 2.3 µmol/L (95% confidence interval [CI], -.1 to 4.7) at baseline to 5.9 µmol/L (3.5-8.3) 5 years after gastric bypass and from 1.0 µmol/L (95% CI, -1.4 to 3.5) to 9.5 µmol/L (95% CI, 7.1-11.9) after duodenal switch; mean between-group difference was -4.8 µmol/L (95% CI, -9.3 to -.3), P = .036. Mean concentrations of primary bile acids increased more after duodenal switch, whereas secondary bile acids increased proportionally across the groups. Higher levels of total bile acids at 5 years were associated with lower body mass index, greater weight loss, and lower total cholesterol. Total bile acid concentrations increased substantially over 5 years after both gastric bypass and duodenal switch, with greater increases in total and primary bile acids after duodenal switch. (Surg Obes Relat Dis 2017;0:000-000.) © 2017 American Society for Metabolic and Bariatric Surgery. All rights reserved. Copyright © 2017 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

Simultaneous determination of nine kinds of dominating bile acids in various snake bile by ultrahigh-performance liquid chromatography with triple quadrupole linear iontrap mass spectrometry.

PubMed

Zhang, Jie; Fan, Yeqin; Gong, Yajun; Chen, Xiaoyong; Wan, Luosheng; Zhou, Chenggao; Zhou, Jiewen; Ma, Shuangcheng; Wei, Feng; Chen, Jiachun; Nie, Jing

2017-11-15

Snake bile is one of the most expensive traditional Chinese medicines (TCMs). However, due to the complicated constitutes of snake bile and the poor ultraviolet absorbance of some trace bile acids (BAs), effective analysis methods for snake bile acids were still unavailable, making it difficult to solve adulteration problems. In present study, ultrahigh-performance liquid chromatography with triple quadrupole linear ion trap mass spectrometry (UHPLC-QqQ-MS/MS) was applied to conduct a quantitative analysis on snake BAs. The mass spectrometer was monitored in the negative ion mode, and multiple-reaction monitoring (MRM) program was used to determine the contents of BAs in snake bile. In all, 61 snake bile from 17 commonly used species of three families (Elapidae, Colubridae and Viperidae), along with five batches of commercial snake bile from four companies, were collected and detected. Nine components, Tauro-3α,12α-dihydroxy-7-oxo-5β-cholenoic acid (T1), Tauro-3α,7α,12α,23R-tetrahydroxy-5β-cholenoic acid (T2), taurocholic acid (TCA), glycocholic acid (GCA), taurochenodeoxycholic acid (TCDCA), taurodeoxycholic acid (TDCA), cholic acid (CA), Tauro-3α,7α-dihydroxy-12-oxo-5β-cholenoic acid (T3), and Tauro-3α,7α,9α,16α-tetrahydroxy-5β-cholenoic acid (T4) were simultaneously and rapidly determined for the first time. In these BAs, T1 and T2, self-prepared with purity above 90%, were first reported with their quantitative determination, and the latter two (T3 and T4) were tentatively determined by quantitative analysis multi-components by single marker (QAMS) method for roughly estimating the components without reference. The developed method was validated with acceptable linearity (r 2 ≥0.995), precision (RSD＜6.5%) and recovery (RSD＜7.5%). It turned out that the contents of BAs among different species were also significantly different; T1 was one of the principle bile acids in some common snake bile, and also was the characteristic one in Viperidae and Elapidae; T2 was the dominant components in Enhydris chinensis. This quantitative study of BAs in snake bile is a remarkable improvement for clarifying the bile acid compositions and evaluating the quality of snake bile. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of the composition of bile acids in bile of patients with adenocarcinoma of the pancreas and benign disease.

PubMed

Rees, David O; Crick, Peter J; Jenkins, Gareth J; Wang, Yuqin; Griffiths, William J; Brown, Tim H; Al-Sarireh, Bilal

2017-11-01

Bile acids have been implicated in the development of gastrointestinal malignancies. Both the specific nature of individual bile acids and their concentration appear key factors in the carcinogenic potency of bile. Using liquid chromatography mass spectrometry (LC-MS) we performed quantitative profiling of bile extracted directly from the common bile duct in 30 patients (15 patients with pancreatic cancer and 15 patients with benign disease). Separation and detection of bile acids was performed using a 1.7μm particle size reversed-phase C 18 LC column at a flow rate of 200μL/min with negative electrospray ionization MS. A significant difference (p=0.018) was seen in the concentration of unconjugated cholic acid in the malignant group (0.643mmol/L) compared to the benign group (0.022mmol/L), with an overall significant difference (p=0.04) seen in the level of total unconjugated bile acids in the malignant group (1.816mmol/L) compared to the benign group (0.069mmol/L). This finding may offer the possibility of both understanding the biology of cancer development in the pancreas, as well as offering a potential diagnostic avenue to explore. However, a larger study is necessary to confirm the alterations in bile acid profiles reported here and explore factors such as diet and microbial populations on the bile acid profiles of these patient groups. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Rapid Determination of Bile Acids in Bile from Various Mammals by Reversed-Phase Ultra-Fast Liquid Chromatography.

PubMed

Si, Gu Leng Ri; Yao, Peng; Shi, Luwen

2015-08-01

A valid and efficient reversed-phase ultra-fast liquid chromatography method was developed for the simultaneous determination of 13 bile acids in the bile of three mammal species, including rat, pig and human gallstone patients. Chromatographic separation was performed with a Shim-pack XR-ODS column, and the mobile phase consisted of acetonitrile and potassium phosphate buffer (pH 2.6) at a flow rate of 0.5 mL min(-1). The linear detection range of most bile acids ranged from 2 to 600 ng µL(-1) with a good correlation coefficient (>0.9995). The precision of each bile acid was <1.8% for intraday and <4.8% for interday. All bile acids were separated in 15 min with satisfactory resolution, and the total analysis time was 18 min, including equilibration. The method was successfully applied in rapid screening of bile samples from the three mammals. Significant metabolic frameworks of bile acids among various species were observed, whereas considerable quantitative variations in both inter- and intraspecies were also observed, especially for gallstone patients. Our results suggest that detecting the change of bile acid profiles could be applied for the diagnosis of gallstone disease. © Crown copyright 2014.

Bile acids: analysis in biological fluids and tissues

PubMed Central

Griffiths, William J.; Sjövall, Jan

2010-01-01

The formation of bile acids/bile alcohols is of major importance for the maintenance of cholesterol homeostasis. Besides their functions in lipid absorption, bile acids/bile alcohols are regulatory molecules for a number of metabolic processes. Their effects are structure-dependent, and numerous metabolic conversions result in a complex mixture of biologically active and inactive forms. Advanced methods are required to characterize and quantify individual bile acids in these mixtures. A combination of such analyses with analyses of the proteome will be required for a better understanding of mechanisms of action and nature of endogenous ligands. Mass spectrometry is the basic detection technique for effluents from chromatographic columns. Capillary liquid chromatography-mass spectrometry with electrospray ionization provides the highest sensitivity in metabolome analysis. Classical gas chromatography-mass spectrometry is less sensitive but offers extensive structure-dependent fragmentation increasing the specificity in analyses of isobaric isomers of unconjugated bile acids. Depending on the nature of the bile acid/bile alcohol mixture and the range of concentration of individuals, different sample preparation sequences, from simple extractions to group separations and derivatizations, are applicable. We review the methods currently available for the analysis of bile acids in biological fluids and tissues, with emphasis on the combination of liquid and gas phase chromatography with mass spectrometry. PMID:20008121

Budesonide treatment is associated with increased bile acid absorption in collagenous colitis.

PubMed

Bajor, A; Kilander, A; Gälman, C; Rudling, M; Ung, K-A

2006-12-01

Bile acid malabsorption is frequent in collagenous colitis and harmful bile acids may play a pathophysiological role. Glucocorticoids increase ileal bile acid transport. Budesonide have its main effect in the terminal ileum. To evaluate whether the symptomatic effect of budesonide is linked to increased uptake of bile acids. Patients with collagenous colitis were treated with budesonide 9 mg daily for 12 weeks. Prior to and after 8 weeks of treatment, the (75)SeHCAT test, an indirect test for the active uptake of bile acid-s, measurements of serum 7alpha-hydroxy-4-cholesten-3-one, an indicator of hepatic bile acid synthesis, and registration of symptoms were performed. The median (75)SeHCAT retention increased from 18% to 35% (P < 0.001, n = 25) approaching the values of healthy controls (38%). The 7alpha-hydroxy-4-cholesten-3-one values decreased significantly among those with initially high synthesis (from 36 to 23 ng/mL, P = 0.04, n = 9); however, for the whole group the values were not altered (19 ng/mL vs. 13 ng/mL, P = 0.23, N.S., n = 19). The normalization of the (75)SeHCAT test and the reduction of bile acid synthesis in patients with initially high synthetic rate, suggests that the effect of budesonide in collagenous colitis may be in part due to decreased bile acid load on the colon.

Roles of the C-terminal domains of human dihydrodiol dehydrogenase isoforms in the binding of substrates and modulators: probing with chimaeric enzymes.

PubMed Central

Matsuura, K; Hara, A; Deyashiki, Y; Iwasa, H; Kume, T; Ishikura, S; Shiraishi, H; Katagiri, Y

1998-01-01

Human liver dihydrodiol dehydrogenase (DD; EC 1.3.1.20) exists in isoforms (DD1, DD2 and DD4) composed of 323 amino acids. DD1 and DD2 share 98% amino acid sequence identity, but show lower identities (approx. 83%) with DD4, in which a marked difference is seen in the C-terminal ten amino acids. DD4 exhibits unique catalytic properties, such as the ability to oxidize both (R)- and (S)-alicyclic alcohols equally, high dehydrogenase activity for bile acids, potent inhibition by steroidal anti-inflammatory drugs and activation by sulphobromophthalein and clofibric acid derivatives. In this study, we have prepared chimaeric enzymes, in which we exchanged the C-terminal 39 residues between the two enzymes. Compared with DD1, CDD1-4 (DD1 with the C-terminal sequence of DD4) had increased kcat/Km values for 3alpha-hydroxy-5beta-androstanes and bile acids of 3-9-fold and decreased values for the other substrates by 5-100-fold. It also became highly sensitive to DD4 inhibitors such as phenolphthalein and hexoestrol. Another chimaeric enzyme, CDD4-1 (DD4 with the C-terminal sequence of DD1), showed the same (S)-stereospecificity for the alicyclic alcohols as DD1, had decreased kcat/Km values for bile acids with 7beta- or 12alpha-hydroxy groups by more than 120-fold and was resistant to inhibition by betamethasone. In addition, the activation effects of sulphobromophthalein and bezafibrate decreased or disappeared for CDD4-1. The recombinant DD4 with the His314-->Pro (the corresponding residue of DD1) mutation showed intermediate changes in the properties between those of wild-type DD4 and CDD4-1. The results indicate that the binding of substrates, inhibitors and activators to the enzymes is controlled by residues in their C-terminal domains; multiple residues co-ordinately act as determinants for substrate specificity and inhibitor sensitivity. PMID:9820821

Long-term effect of medical treatment of diarrhoea in 377 patients with SeHCAT scan diagnosed bile acid malabsorption from 2003 to 2016; a retrospective study.

PubMed

Damsgaard, B; Dalby, H R; Krogh, K; Jørgensen, S M D; Arveschough, A K; Agnholt, J; Dahlerup, J F; Jørgensen, S P

2018-04-01

Excessive amounts of bile acids entering the colon due to bile acid malabsorption cause chronic bile acid diarrhoea. Diagnosis is possible by measuring the retention fraction of orally ingested 75 Selenium homotaurocholic acid (SeHCAT). The knowledge of long-term effects of medical treatment is sparse. To describe diarrhoea, adherence to treatment, treatment effects and quality of life in a large, well-defined cohort of patients with bile acid diarrhoea. A retrospective survey was performed among 594 patients with bile acid malabsorption verified by SeHCAT scans at our unit between 2003 and 2016. Questionnaires about medical history, diarrhoea, use of medication, and quality of life scores were mailed to all patients. Among 594 patients 377 (69%) responded. Among respondents, 121 (32%) had bile acid diarrhoea due to ileal disease or resection (type 1), 198 (52%) idiopathic bile acid diarrhoea (type 2) and 58 (16%) bile acid diarrhoea due to other non-ileal disease, mainly cholecystectomy (type 3). At follow-up, half of the patients, 184 (50%), reported improvement of diarrhoea. However, 273 patients (74%) still reported diarrhoea and 234 (62%) regularly used anti-diarrhoeal medication. In spite of treatment, 235 (64%) considered reduced quality of life by diarrhoea and 184 (50%) reported that diarrhoea was unaltered or worse than before established diagnosis. Many patients with bile acid diarrhoea continue to have bothersome diarrhoea in spite of correct diagnosis and treatment. © 2018 John Wiley & Sons Ltd.

Profiling of urinary bile acids in piglets by a combination of enzymatic deconjugation and targeted LC-MRM-MS

USDA-ARS?s Scientific Manuscript database

Bile acids (BAs) have an important role in the control of fat, glucose and cholesterol metabolism. Synthesis of bile acids is the major pathway for the metabolism of cholesterol and for the excretion of excess cholesterol in mammals. Bile acid intermediates and/or their metabolites are excreted in...

Mixed micelles of 7,12-dioxolithocholic acid and selected hydrophobic bile acids: interaction parameter, partition coefficient of nitrazepam and mixed micelles haemolytic potential.

PubMed

Poša, Mihalj; Tepavčević, Vesna

2011-09-01

The formation of mixed micelles built of 7,12-dioxolithocholic and the following hydrophobic bile acids was examined by conductometric method: cholic (C), deoxycholic (D), chenodeoxycholic (CD), 12-oxolithocholic (12-oxoL), 7-oxolithocholic (7-oxoL), ursodeoxycholic (UD) and hiodeoxycholic (HD). Interaction parameter (β) in the studied binary mixed micelles had negative value, suggesting synergism between micelle building units. Based on β value, the hydrophobic bile acids formed two groups: group I (C, D and CD) and group II (12-oxoL, 7-oxoL, UD and HD). Bile acids from group II had more negative β values than bile acids from group I. Also, bile acids from group II formed intermolecular hydrogen bonds in aggregates with both smaller (2) and higher (4) aggregation numbers, according to the analysis of their stereochemical (conformational) structures and possible structures of mixed micelles built of these bile acids and 7,12-dioxolithocholic acid. Haemolytic potential and partition coefficient of nitrazepam were higher in mixed micelles built of the more hydrophobic bile acids (C, D, CD) and 7,12-dioxolithocholic acid than in micelles built only of 7,12-dioxolithocholic acid. On the other hand, these mixed micelles still had lower values of haemolytic potential than micelles built of C, D or CD. The mixed micelles that included bile acids: 12-oxoL, 7-oxoL, UD or HD did not significantly differ from the micelles of 7,12-dioxolithocholic acid, observing the values of their haemolytic potential. Copyright © 2011 Elsevier B.V. All rights reserved.

Functional and probiotic attributes of an indigenous isolate of Lactobacillus plantarum.

PubMed

Kaushik, Jai K; Kumar, Ashutosh; Duary, Raj K; Mohanty, Ashok K; Grover, Sunita; Batish, Virender K

2009-12-01

Probiotic microorganisms favorably alter the intestinal microflora balance, promote intestinal integrity and mobility, inhibit the growth of harmful bacteria and increase resistance to infection. Probiotics are increasingly used in nutraceuticals, functional foods or in microbial interference treatment. However, the effectiveness of probiotic organism is considered to be population-specific due to variation in gut microflora, food habits and specific host-microbial interactions. Most of the probiotic strains available in the market are of western or European origin, and a strong need for exploring new indigenous probiotic organisms is felt. An indigenous isolate Lp9 identified as Lactobacillus plantarum by molecular-typing methods was studied extensively for its functional and probiotic attributes, viz., acid and bile salt tolerance, cell surface hydrophobicity, autoaggregation and Caco-2 cell-binding as well as antibacterial and antioxidative activities. Lp9 isolate could survive 2 h incubation at pH 1.5-2.0 and toxicity of 1.5-2.0% oxgall bile. Lp9 could deconjugate major bile salts like glycocholate and deoxytaurocholate, indicating its potential to cause hypocholesterolemia. The isolate exhibited cell-surface hydrophobicity of approximately 37% and autoaggregation of approximately 31%. Presence of putative probiotic marker genes like mucus-binding protein (mub), fibronectin-binding protein (fbp) and bile salt hydrolase (bsh) were confirmed by PCR. Presence of these genes suggested the possibility of specific interaction and colonization potential of Lp9 isolate in the gut, which was also suggested by a good adhesion ratio of 7.4+/-1.3% with Caco-2 cell line. The isolate demonstrated higher free radical scavenging activity than standard probiotics L. johnsonii LA1 and L. acidophilus LA7. Lp9 also exhibited antibacterial activity against E. coli, L. monocytogenes, S. typhi, S. aureus and B. cereus. The indigenous Lactobacillus plantarum Lp9 exhibited high resistance against low pH and bile and possessed antibacterial, antioxidative and cholesterol lowering properties with a potential for exploitation in the development of indigenous functional food or nutraceuticals.

Expression and role of the genes involved in the transport of bile acids in the liver and kidneys in mice.

PubMed

Attakpa, Eugène S; Djibril, Naguibou M; Baba-Moussa, Farid; Yessoufou, Ganiou; Sezan, Alphonse

2013-01-01

Bile acids are synthesized in the liver from cholesterol. This study investigated the impact and expression of different carriers of bile acid in the liver and kidneys. Eight-week-old male mice were used, which were fed for 15 days and divided into two groups: 15 mice fed with standard diet (control group) and another 15 mice fed with a rich diet of 5% cholesterol (second group). Bile acid dosage was based on their oxidation by 7α hydroxyl-steroid dehydrogenize. The mRNA expression was quantitatively analyzed by the real time of polymerase chain reaction (RT-PCR), and the expression of the renal carrier bile acid protein was analyzed by Western blot. The expression of bile salt export pump involved in the uptake of bile acids in the basolateral membrane of hepatocytes revealed no differences between the two groups of mice. However, the expression of multidrug resistance-associated protein 2 was reduced in mice of the second group. Moreover, the expressions of organic anion transporting polypeptide 4, organic anion transporting polypeptide 1, and sodium taurocholate co-transporting polypeptide (Ntcp) involved in the uptake of bile acids in the apical pole of hepatocytes are suppressed in mice of the second group. The expression of multidrug resistance-associated protein 3 involved in the secretion of bile acids in the apical membrane of hepatocytes revealed no significant differences between the two groups. In mice of the second group, blood concentration of bile acids on the last day was increased. In those mice, the expression of intestinal bile acid transporter was reduced in the kidneys compared with the control mice.

INTRACELLULAR SIGNALING BY BILE ACIDS

PubMed Central

Anwer, Mohammed Sawkat

2014-01-01

Bile acids, synthesized from cholesterol, are known to produce beneficial as well as toxic effects in the liver. The beneficial effects include choleresis, immunomodulation, cell survival, while the toxic effects include cholestasis, apoptosis and cellular toxicity. It is believed that bile acids produce many of these effects by activating intracellular signaling pathways. However, it has been a challenge to relate intracellular signaling to specific and at times opposing effects of bile acids. It is becoming evident that bile acids produce different effects by activating different isoforms of phosphoinositide 3-kinase (PI3K), Protein kinase Cs (PKCs), and mitogen activated protein kinases (MAPK). Thus, the apoptotic effect of bile acids may be mediated via PI3K-110γ, while cytoprotection induce by cAMP-GEF pathway involves activation of PI3K-p110α/β isoforms. Atypical PKCζ may mediate beneficial effects and nPKCε may mediate toxic effects, while cPKCα and nPKCδ may be involved in both beneficial and toxic effects of bile acids. The opposing effects of nPKCδ activation may depend on nPKCδ phosphorylation site(s). Activation of ERK1/2 and JNK1/2 pathway appears to mediate beneficial and toxic effects, respectively, of bile acids. Activation of p38α MAPK and p38β MAPK may mediate choleretic and cholestatic effects, respectively, of bile acids. Future studies clarifying the isoform specific effects on bile formation should allow us to define potential therapeutic targets in the treatment of cholestatic disorders. PMID:25378891

All-trans retinoic acid regulates hepatic bile acid homeostasis

PubMed Central

Yang, Fan; He, Yuqi; Liu, Hui-Xin; Tsuei, Jessica; Jiang, Xiaoyue; Yang, Li; Wang, Zheng-Tao; Wan, Yu-Jui Yvonne

2014-01-01

Retinoic acid (RA) and bile acids share common roles in regulating lipid homeostasis and insulin sensitivity. In addition, the receptor for RA (retinoid x receptor) is a permissive partner of the receptor for bile acids, farnesoid x receptor (FXR/NR1H4). Thus, RA can activate the FXR-mediated pathway as well. The current study was designed to understand the effect of all-trans RA on bile acid homeostasis. Mice were fed an all-trans RA-supplemented diet and the expression of 46 genes that participate in regulating bile acid homeostasis was studied. The data showed that all-trans RA has a profound effect in regulating genes involved in synthesis and transport of bile acids. All-trans RA treatment reduced the gene expression levels of Cyp7a1, Cyp8b1, and Akr1d1, which are involved in bile acid synthesis. All-trans RA also decreased the hepatic mRNA levels of Lrh-1 (Nr5a2) and Hnf4α (Nr2a1), which positively regulate the gene expression of Cyp7a1 and Cyp8b1. Moreover, all-trans RA induced the gene expression levels of negative regulators of bile acid synthesis including hepatic Fgfr4, Fxr, and Shp (Nr0b2) as well as ileal Fgf15. All-trans RA also decreased the expression of Abcb11 and Slc51b, which have a role in bile acid transport. Consistently, all-trans RA reduced hepatic bile acid levels and the ratio of CA/CDCA, as demonstrated by liquid chromatography-mass spectrometry. The data suggest that all-trans RA-induced SHP may contribute to the inhibition of CYP7A1 and CYP8B1, which in turn reduces bile acid synthesis and affects lipid absorption in the gastrointestinal tract. PMID:25175738

Identification of the anti-oxidant components in a two-step solvent extract of bovine bile lipid: Application of reverse phase HPLC, mass spectrometry and fluorimetric assays.

PubMed

Singh, Namrata; Bhattacharyya, Debasish

2016-04-15

An ether extract of nine different bacterial metabolites in combination with two solvent extract (ether followed by ethanol) of bile lipids from ox gall bladder is used as an immune stimulator drug. Over the years bile acids are discussed regarding their anti-oxidant and lipid peroxidation properties. Since some of the bile acids are known to be potent antioxidants, presence of similar activity in the solvent extract of ox bile lipid was investigated using TLC and reverse phase HPLC systems. Fractions from HPLC were analyzed with mass spectrometry using electrospray ionization. The presence of twelve different bile acids along with other substances in small proportions including fatty acids, sulfate conjugates and bile pigments were confirmed. The twelve separated peaks had similar retention times as those of tauroursodeoxycholic acid, glycoursodeoxycholic acid, taurocholic acid, glycocholic acid, glycochenodeoxycholic acid, taurochenodeoxycholic acid, taurodeoxycholic acid, cholic acid, ursodeoxycholic acid, chenodeoxycholic acid, deoxycholic acid, and lithocholic acid. Subsequently, all fractions were tested for their anti-oxidative property on HepG2 cells exposed to H2O2 that served as an oxidative injury model. Four fluorescent dyes H2DCF DA, MitoSOX red, Amplex red and DAF-2 DA were used for estimation of reactive radicals in the HepG2 cells. Among the separated bile acids, tauroursodeoxycholic acid, glycoursodeoxycholic acid and ursodeoxycholic acid prevented the HepG2 cells from H2O2-induced oxidative stress. Copyright © 2015 Elsevier B.V. All rights reserved.

Glycyrrhizin and glycyrrhetinic acid inhibits alpha-naphthyl isothiocyanate-induced liver injury and bile acid cycle disruption.

PubMed

Wang, Haina; Fang, Zhong-Ze; Meng, Ran; Cao, Yun-Feng; Tanaka, Naoki; Krausz, Kristopher W; Gonzalez, Frank J

2017-07-01

Alpha-naphthyl isothiocyanate (ANIT) is a common hepatotoxicant experimentally used to reproduce the pathologies of drug-induced liver injury in humans, but the mechanism of its toxicity remains unclear. To determine the metabolic alterations following ANIT exposure, metabolomic analyses was performed by use of liquid chromatography-mass spectrometry. Partial least squares discriminant analysis (PLS-DA) of liver, serum, bile, ileum, and cecum of vehicle- and ANIT-treated mice revealed significant alterations of individual bile acids, including increased tauroursodeoxycholic acid, taurohydrodeoxycholic acid, taurochenodeoxycholic acid, and taurodeoxycholic acid, and decreased ω-, β- and tauro-α/β- murideoxycholic acid, cholic acid, and taurocholic acid in the ANIT-treated groups. In accordance with these changes, ANIT treatment altered the expression of mRNAs encoded by genes responsible for the metabolism and transport of bile acids and cholesterol. Pre-treatment of glycyrrhizin (GL) and glycyrrhetinic acid (GA) prevented ANIT-induced liver damage and reversed the alteration of bile acid metabolites and Cyp7a1, Npc1l1, Mttp, and Acat2 mRNAs encoding bile acid transport and metabolism proteins. These results suggested that GL/GA could prevent drug-induced liver injury and ensuing disruption of bile acid metabolism in humans. Published by Elsevier B.V.

Effect of a high-fat-high-cholesterol diet on gallbladder bile acid composition and gallbladder motility in dogs.

PubMed

Kakimoto, Toshiaki; Kanemoto, Hideyuki; Fukushima, Kenjiro; Ohno, Koichi; Tsujimoto, Hajime

2017-12-01

OBJCTIVE To investigate the effects of dietary lipid overload on bile acid metabolism and gallbladder motility in healthy dogs. ANIMALS 7 healthy Beagles. PROCEDURES In a crossover study, dogs were fed a high-fat-high-cholesterol diet (HFCD) or a low-fat diet (LFD) for a period of 2 weeks. After a 4-month washout period, dogs were fed the other diet for 2 weeks. Before and at the end of each feeding period, the concentrations of each of the gallbladder bile acids, cholecystokinin (CCK)-induced gallbladder motility, and bile acid metabolism-related hepatic gene expression were examined in all dogs. RESULTS The HFCD significantly increased plasma total cholesterol concentrations. The HFCD also increased the concentration of taurochenodeoxycholic acid and decreased the concentration of taurocholic acid in bile and reduced gallbladder contractility, whereas the LFD significantly decreased the concentration of taurodeoxycholic acid in bile. Gene expression analysis revealed significant elevation of cholesterol 7α-hydroxylase mRNA expression after feeding the HFCD for 2 weeks, but the expression of other genes was unchanged. CONCLUSIONS AND CLINICAL RELEVANCE Feeding the HFCD and LFD for 2 weeks induced changes in gallbladder bile acid composition and gallbladder motility in dogs. In particular, feeding the HFCD caused an increase in plasma total cholesterol concentration, an increase of hydrophobic bile acid concentration in bile, and a decrease in gallbladder sensitivity to CCK. These results suggested that similar bile acid compositional changes and gallbladder hypomotility might be evident in dogs with hyperlipidemia.

Bile acid profiling and quantification in biofluids using ultra-performance liquid chromatography tandem mass spectrometry.

PubMed

Sarafian, Magali H; Lewis, Matthew R; Pechlivanis, Alexandros; Ralphs, Simon; McPhail, Mark J W; Patel, Vishal C; Dumas, Marc-Emmanuel; Holmes, Elaine; Nicholson, Jeremy K

2015-10-06

Bile acids are important end products of cholesterol metabolism. While they have been identified as key factors in lipid emulsification and absorption due to their detergent properties, bile acids have also been shown to act as signaling molecules and intermediates between the host and the gut microbiota. To further the investigation of bile acid functions in humans, an advanced platform for high throughput analysis is essential. Herein, we describe the development and application of a 15 min UPLC procedure for the separation of bile acid species from human biofluid samples requiring minimal sample preparation. High resolution time-of-flight mass spectrometry was applied for profiling applications, elucidating rich bile acid profiles in both normal and disease state plasma. In parallel, a second mode of detection was developed utilizing tandem mass spectrometry for sensitive and quantitative targeted analysis of 145 bile acid (BA) species including primary, secondary, and tertiary bile acids. The latter system was validated by testing the linearity (lower limit of quantification, LLOQ, 0.25-10 nM and upper limit of quantification, ULOQ, 2.5-5 μM), precision (≈6.5%), and accuracy (81.2-118.9%) on inter- and intraday analysis achieving good recovery of bile acids (serum/plasma 88% and urine 93%). The ultra performance liquid chromatography-mass spectrometry (UPLC-MS)/MS targeted method was successfully applied to plasma, serum, and urine samples in order to compare the bile acid pool compositional difference between preprandial and postprandial states, demonstrating the utility of such analysis on human biofluids.

Specific bile acids inhibit hepatic fatty acid uptake

PubMed Central

Nie, Biao; Park, Hyo Min; Kazantzis, Melissa; Lin, Min; Henkin, Amy; Ng, Stephanie; Song, Sujin; Chen, Yuli; Tran, Heather; Lai, Robin; Her, Chris; Maher, Jacquelyn J.; Forman, Barry M.; Stahl, Andreas

2012-01-01

Bile acids are known to play important roles as detergents in the absorption of hydrophobic nutrients and as signaling molecules in the regulation of metabolism. Here we tested the novel hypothesis that naturally occurring bile acids interfere with protein-mediated hepatic long chain free fatty acid (LCFA) uptake. To this end stable cell lines expressing fatty acid transporters as well as primary hepatocytes from mouse and human livers were incubated with primary and secondary bile acids to determine their effects on LCFA uptake rates. We identified ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA) as the two most potent inhibitors of the liver-specific fatty acid transport protein 5 (FATP5). Both UDCA and DCA were able to inhibit LCFA uptake by primary hepatocytes in a FATP5-dependent manner. Subsequently, mice were treated with these secondary bile acids in vivo to assess their ability to inhibit diet-induced hepatic triglyceride accumulation. Administration of DCA in vivo via injection or as part of a high-fat diet significantly inhibited hepatic fatty acid uptake and reduced liver triglycerides by more than 50%. In summary, the data demonstrate a novel role for specific bile acids, and the secondary bile acid DCA in particular, in the regulation of hepatic LCFA uptake. The results illuminate a previously unappreciated means by which specific bile acids, such as UDCA and DCA, can impact hepatic triglyceride metabolism and may lead to novel approaches to combat obesity-associated fatty liver disease. PMID:22531947

Ion-neutral Clustering of Bile Acids in Electrospray Ionization Across UPLC Flow Regimes

NASA Astrophysics Data System (ADS)

Brophy, Patrick; Broeckling, Corey D.; Murphy, James; Prenni, Jessica E.

2018-02-01

Bile acid authentic standards were used as model compounds to quantitatively evaluate complex in-source phenomenon on a UPLC-ESI-TOF-MS operated in the negative mode. Three different diameter columns and a ceramic-based microfluidic separation device were utilized, allowing for detailed descriptions of bile acid behavior across a wide range of flow regimes and instantaneous concentrations. A custom processing algorithm based on correlation analysis was developed to group together all ion signals arising from a single compound; these grouped signals produce verified compound spectra for each bile acid at each on-column mass loading. Significant adduction was observed for all bile acids investigated under all flow regimes and across a wide range of bile acid concentrations. The distribution of bile acid containing clusters was found to depend on the specific bile acid species, solvent flow rate, and bile acid concentration. Relative abundancies of each cluster changed non-linearly with concentration. It was found that summing all MS level (low collisional energy) ions and ion-neutral adducts arising from a single compound improves linearity across the concentration range (0.125-5 ng on column) and increases the sensitivity of MS level quantification. The behavior of each cluster roughly follows simple equilibrium processes consistent with our understanding of electrospray ionization mechanisms and ion transport processes occurring in atmospheric pressure interfaces. [Figure not available: see fulltext.

Disruption of the sterol 27-hydroxylase gene in mice results in hepatomegaly and hypertriglyceridemia. Reversal by cholic acid feeding.

PubMed

Repa, J J; Lund, E G; Horton, J D; Leitersdorf, E; Russell, D W; Dietschy, J M; Turley, S D

2000-12-15

Sterol 27-hydroxylase (CYP27) participates in the conversion of cholesterol to bile acids. We examined lipid metabolism in mice lacking the Cyp27 gene. On normal rodent chow, Cyp27(-/-) mice have 40% larger livers, 45% larger adrenals, 2-fold higher hepatic and plasma triacylglycerol concentrations, a 70% higher rate of hepatic fatty acid synthesis, and a 70% increase in the ratio of oleic to stearic acid in the liver versus Cyp27(+/+) controls. In Cyp27(-/-) mice, cholesterol 7alpha-hydroxylase activity is increased 5-fold, but bile acid synthesis and pool size are 47 and 27%, respectively, of those in Cyp27(+/+) mice. Intestinal cholesterol absorption decreases from 54 to 4% in knockout mice, while fecal neutral sterol excretion increases 2.5-fold. A compensatory 2.5-fold increase in whole body cholesterol synthesis occurs in Cyp27(-/-) mice, principally in liver, adrenal, small intestine, lung, and spleen. The mRNA for the cholesterogenic transcription factor sterol regulatory element-binding protein-2 (SREBP-2) and mRNAs for SREBP-2-regulated cholesterol biosynthetic genes are elevated in livers of mutant mice. In addition, the mRNAs encoding the lipogenic transcription factor SREBP-1 and SREBP-1-regulated monounsaturated fatty acid biosynthetic enzymes are also increased. Hepatic synthesis of fatty acids and accumulation of triacylglycerols increases in Cyp27(-/-) mice and is associated with hypertriglyceridemia. Cholic acid feeding reverses hepatomegaly and hypertriglyceridemia but not adrenomegaly in Cyp27(-/-) mice. These studies confirm the importance of CYP27 in bile acid synthesis and they reveal an unexpected function of the enzyme in triacylglycerol metabolism.

A novel formulation of veggies with potent liver detoxifying activity.

PubMed

Jain, Mohit M; Kumari, Nirmala; Rai, Geeta

2015-01-01

LXR (encoded by NR1H2 and 3) and FXR (known as bile acid receptor) encoded by NR1H4 (nuclear receptor subfamily 1, group H and member 4) are nuclear receptors in humans and are important regulators of bile acid production, cholesterol, fatty acid and glucose homeostasis hence responsible for liver detoxification. Several strategies for drug design with numerous ligands for this target have failed owing to the inability of the ligand to access the target/receptor or their early metabolisation. In this work, we have evaluated FXR and LXR structure bound with agonist and compared the binding energy affinity of active ligands present in live green-real veggies with reference drugs (ligands) present in the market. A high throughput screening combined with molecular docking, absorption, distribution, metabolism, excretion and toxicity (ADMET) predictions, log P values and percentage of human oral absorption value led to the identification of two compounds present in live green-real veggies with strong potential for liver detoxification.

Bile acid disease: the emerging epidemic.

PubMed

Oduyebo, Ibironke; Camilleri, Michael

2017-05-01

Our objective was to review advances in bile acids in health and disease published in the last 2 years. Bile acid diarrhea (BAD) is recognized as a common cause of chronic diarrhea, and its recognition has been facilitated by development of new screening tests. Primary BAD can account for 30% of cases of chronic diarrhea. The mechanisms leading to BAD include inadequate feedback regulation by fibroblast growth factor 19 (FGF-19) from ileal enterocytes, abnormalities in synthesis or degradation of proteins involved in FGF-19 regulation in hepatocytes and variations as a function of the bile acid receptor, TGR5 (GPBAR1). SeHCAT is the most widely used test for diagnosis of BAD. There has been significant validation of fasting serum FGF-19 and 7 α-hydroxy-cholesten-3-one (C4), a surrogate measure of bile acid synthesis. Bile acid sequestrants are the primary treatments for BAD; the farnesoid X-receptor-FGF-19 pathway provides alternative therapeutic targets for BAD. Bile acid-stimulated intestinal mechanisms contribute to the beneficial effects of bariatric surgery on obesity, glycemic control and the treatment of recurrent Clostridium difficile infection. Renewed interest in the role of bile acids is leading to novel management of diverse diseases besides BAD.

Strong activation of bile acid-sensitive ion channel (BASIC) by ursodeoxycholic acid

PubMed Central

Wiemuth, Dominik; Sahin, Hacer; Lefèvre, Cathérine M.T.; Wasmuth, Hermann E.; Gründer, Stefan

2013-01-01

Bile acid-sensitive ion channel (BASIC) is a member of the DEG/ENaC gene family of unknown function. Rat BASIC (rBASIC) is inactive at rest. We have recently shown that cholangiocytes, the epithelial cells lining the bile ducts, are the main site of BASIC expression in the liver and identified bile acids, in particular hyo- and chenodeoxycholic acid, as agonists of rBASIC. Moreover, it seems that extracellular divalent cations stabilize the resting state of rBASIC, because removal of extracellular divalent cations opens the channel. In this addendum, we demonstrate that removal of extracellular divalent cations potentiates the activation of rBASIC by bile acids, suggesting an allosteric mechanism. Furthermore, we show that rBASIC is strongly activated by the anticholestatic bile acid ursodeoxycholic acid (UDCA), suggesting that BASIC might mediate part of the therapeutic effects of UDCA. PMID:23064163

Structure based classification for bile salt export pump (BSEP) inhibitors using comparative structural modeling of human BSEP

NASA Astrophysics Data System (ADS)

Jain, Sankalp; Grandits, Melanie; Richter, Lars; Ecker, Gerhard F.

2017-06-01

The bile salt export pump (BSEP) actively transports conjugated monovalent bile acids from the hepatocytes into the bile. This facilitates the formation of micelles and promotes digestion and absorption of dietary fat. Inhibition of BSEP leads to decreased bile flow and accumulation of cytotoxic bile salts in the liver. A number of compounds have been identified to interact with BSEP, which results in drug-induced cholestasis or liver injury. Therefore, in silico approaches for flagging compounds as potential BSEP inhibitors would be of high value in the early stage of the drug discovery pipeline. Up to now, due to the lack of a high-resolution X-ray structure of BSEP, in silico based identification of BSEP inhibitors focused on ligand-based approaches. In this study, we provide a homology model for BSEP, developed using the corrected mouse P-glycoprotein structure (PDB ID: 4M1M). Subsequently, the model was used for docking-based classification of a set of 1212 compounds (405 BSEP inhibitors, 807 non-inhibitors). Using the scoring function ChemScore, a prediction accuracy of 81% on the training set and 73% on two external test sets could be obtained. In addition, the applicability domain of the models was assessed based on Euclidean distance. Further, analysis of the protein-ligand interaction fingerprints revealed certain functional group-amino acid residue interactions that could play a key role for ligand binding. Though ligand-based models, due to their high speed and accuracy, remain the method of choice for classification of BSEP inhibitors, structure-assisted docking models demonstrate reasonably good prediction accuracies while additionally providing information about putative protein-ligand interactions.

Dietary fish oil regulates gene expression of cholesterol and bile acid transporters in mice.

PubMed

Kamisako, Toshinori; Tanaka, Yuji; Ikeda, Takanori; Yamamoto, Kazuo; Ogawa, Hiroshi

2012-03-01

  Fish oil rich in n-3 polyunsaturated fatty acids is known to affect hepatic lipid metabolism. Several studies have demonstrated that fish oil may affect the bile acid metabolism as well as lipid metabolism, whereas only scarce data are available. The aim of this study was to investigate the effect of fish oil on the gene expression of the transporters and enzymes related to bile acid as well as lipid metabolism in the liver and small intestine.   Seven-week old male C57BL/6 mice were fed diets enriched in 10% soybean oil or 10% fish oil for 4 weeks. After 4 weeks, blood, liver and small intestine were obtained.   Hepatic mRNA expression of lipids (Abcg5/8, multidrug resistance gene product 2) and bile acids transporters (bile salt export pump, multidrug resistance associated protein 2 and 3, organic solute transporter α) was induced in fish oil-fed mice. Hepatic Cyp8b1, Cyp27a1 and bile acid CoA : amino acid N-acyltransferase were increased in fish oil-fed mice compared with soybean-oil fed mice. Besides, intestinal cholesterol (Abcg5/8) and bile acid transporters (multidrug resistance associated protein 2 and organic solute transporter α) were induced in fish oil-fed mice.   Fish oil induced the expression of cholesterol and bile acid transporters not only in liver but in intestine. The upregulation of Abcg5/g8 by fish oil is caused by an increase in cellular 27-HOC through Cyp27a1 induction. The hepatic induction of bile acid synthesis through Cyp27a1 may upregulate expression of bile acid transporters in both organs. © 2012 The Japan Society of Hepatology.

Bile acid composition of gallbladder contents in dogs with gallbladder mucocele and biliary sludge.

PubMed

Kakimoto, Toshiaki; Kanemoto, Hideyuki; Fukushima, Kenjiro; Ohno, Koichi; Tsujimoto, Hajime

2017-02-01

OBJECTIVE To examine bile acid composition of gallbladder contents in dogs with gallbladder mucocele and biliary sludge. ANIMALS 18 dogs with gallbladder mucocele (GBM group), 8 dogs with immobile biliary sludge (i-BS group), 17 dogs with mobile biliary sludge (m-BS group), and 14 healthy dogs (control group). PROCEDURES Samples of gallbladder contents were obtained by use of percutaneous ultrasound-guided cholecystocentesis or during cholecystectomy or necropsy. Concentrations of 15 bile acids were determined by use of highperformance liquid chromatography, and a bile acid compositional ratio was calculated for each group. RESULTS Concentrations of most bile acids in the GBM group were significantly lower than those in the control and m-BS groups. Compositional ratio of taurodeoxycholic acid, which is 1 of 3 major bile acids in dogs, was significantly lower in the GBM and i-BS groups, compared with ratios for the control and m-BS groups. The compositional ratio of taurocholic acid was significantly higher and that of taurochenodeoxycholic acid significantly lower in the i-BS group than in the control group. CONCLUSIONS AND CLINICAL RELEVANCE In this study, concentrations and fractions of bile acids in gallbladder contents were significantly different in dogs with gallbladder mucocele or immobile biliary sludge, compared with results for healthy control dogs. Studies are needed to determine whether changes in bile acid composition are primary or secondary events of gallbladder abnormalities.

The ulcerogenic effect of bile and bile acid in rats during immobilization stress

NASA Technical Reports Server (NTRS)

Weisener, J.

1980-01-01

The effect of different concentrations of oxen bile and individual bile acids or their sodium salts on the gastric mucosa of rats was investigated in combination with immobilization stress. A statistically significant higher frequency of ulcers was only determined in the application of 10% oxen bile. Dosages on 10% sodium glycocholic acid demonstrated strong toxic damage with atonic dilation of the stomach and extensive mucosal bleeding.

Changes in the faecal bile acid profile in dogs fed dry food vs high content of beef: a pilot study.

PubMed

Herstad, Kristin Marie Valand; Rønning, Helene Thorsen; Bakke, Anne Marie; Moe, Lars; Skancke, Ellen

2018-05-11

Dogs are fed various diets, which also include components of animal origin. In humans, a high-fat/low-fibre diet is associated with higher faecal levels of bile acids, which can influence intestinal health. It is unknown how an animal-based diet high in fat and low in fibre influences the faecal bile acid levels and intestinal health in dogs. This study investigated the effects of high intake of minced beef on the faecal bile acid profile in healthy, adult, client-owned dogs (n = 8) in a 7-week trial. Dogs were initially adapted to the same commercial dry food. Thereafter, incremental substitution of the dry food by boiled minced beef over 3 weeks resulted in a diet in which 75% of each dog's total energy requirement was provided as minced beef during week 5. Dogs were subsequently reintroduced to the dry food for the last 2 weeks of the study. The total taurine and glycine-conjugated bile acids, the primary bile acids chenodeoxycholic acid and cholic acid, and the secondary bile acids lithocholic acid, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) were analysed, using liquid chromatography-tandem mass spectrometry. The faecal quantities of DCA were significantly higher in dogs fed the high minced beef diet. These levels reversed when dogs were reintroduced to the dry food diet. The faecal levels of UDCA and taurine-conjugated bile acids had also increased in response to the beef diet, but this was only significant when compared to the last dry food period. These results suggest that an animal-based diet with high-fat/low-fibre content can influence the faecal bile acids levels. The consequences of this for canine colonic health will require further investigation.

In Vitro Modeling of Bile Acid Processing by the Human Fecal Microbiota.

PubMed

Martin, Glynn; Kolida, Sofia; Marchesi, Julian R; Want, Elizabeth; Sidaway, James E; Swann, Jonathan R

2018-01-01

Bile acids, the products of concerted host and gut bacterial metabolism, have important signaling functions within the mammalian metabolic system and a key role in digestion. Given the complexity of the mega-variate bacterial community residing in the gastrointestinal tract, studying associations between individual bacterial genera and bile acid processing remains a challenge. Here, we present a novel in vitro approach to determine the bacterial genera associated with the metabolism of different primary bile acids and their potential to contribute to inter-individual variation in this processing. Anaerobic, pH-controlled batch cultures were inoculated with human fecal microbiota and treated with individual conjugated primary bile acids (500 μg/ml) to serve as the sole substrate for 24 h. Samples were collected throughout the experiment (0, 5, 10, and 24 h) and the bacterial composition was determined by 16S rRNA gene sequencing and the bile acid signatures were characterized using a targeted ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) approach. Data fusion techniques were used to identify statistical bacterial-metabolic linkages. An increase in gut bacteria associated bile acids was observed over 24 h with variation in the rate of bile acid metabolism across the volunteers ( n = 7). Correlation analysis identified a significant association between the Gemmiger genus and the deconjugation of glycine conjugated bile acids while the deconjugation of taurocholic acid was associated with bacteria from the Eubacterium and Ruminococcus genera. A positive correlation between Dorea and deoxycholic acid production suggest a potential role for this genus in cholic acid dehydroxylation. A slower deconjugation of taurocholic acid was observed in individuals with a greater abundance of Parasutterella and Akkermansia . This work demonstrates the utility of integrating compositional (metataxonomics) and functional (metabonomics) systems biology approaches, coupled to in vitro model systems, to study the biochemical capabilities of bacteria within complex ecosystems. Characterizing the dynamic interactions between the gut microbiota and the bile acid pool enables a greater understanding of how variation in the gut microbiota influences host bile acid signatures, their associated functions and their implications for health.

Bile acids induce necrosis in pancreatic stellate cells dependent on calcium entry and sodium‐driven bile uptake

PubMed Central

Jakubowska, Monika A.; Gerasimenko, Julia V.; Gerasimenko, Oleg V.; Petersen, Ole H.

2016-01-01

Key points Acute biliary pancreatitis is a sudden and severe condition initiated by bile reflux into the pancreas.Bile acids are known to induce Ca2+ signals and necrosis in isolated pancreatic acinar cells but the effects of bile acids on stellate cells are unexplored.Here we show that cholate and taurocholate elicit more dramatic Ca2+ signals and necrosis in stellate cells compared to the adjacent acinar cells in pancreatic lobules; whereas taurolithocholic acid 3‐sulfate primarily affects acinar cells.Ca2+ signals and necrosis are strongly dependent on extracellular Ca2+ as well as Na+; and Na+‐dependent transport plays an important role in the overall bile acid uptake in pancreatic stellate cells.Bile acid‐mediated pancreatic damage can be further escalated by bradykinin‐induced signals in stellate cells and thus killing of stellate cells by bile acids might have important implications in acute biliary pancreatitis. Abstract Acute biliary pancreatitis, caused by bile reflux into the pancreas, is a serious condition characterised by premature activation of digestive enzymes within acinar cells, followed by necrosis and inflammation. Bile acids are known to induce pathological Ca2+ signals and necrosis in acinar cells. However, bile acid‐elicited signalling events in stellate cells remain unexplored. This is the first study to demonstrate the pathophysiological effects of bile acids on stellate cells in two experimental models: ex vivo (mouse pancreatic lobules) and in vitro (human cells). Sodium cholate and taurocholate induced cytosolic Ca2+ elevations in stellate cells, larger than those elicited simultaneously in the neighbouring acinar cells. In contrast, taurolithocholic acid 3‐sulfate (TLC‐S), known to induce Ca2+ oscillations in acinar cells, had only minor effects on stellate cells in lobules. The dependence of the Ca2+ signals on extracellular Na+ and the presence of sodium–taurocholate cotransporting polypeptide (NTCP) indicate a Na+‐dependent bile acid uptake mechanism in stellate cells. Bile acid treatment caused necrosis predominantly in stellate cells, which was abolished by removal of extracellular Ca2+ and significantly reduced in the absence of Na+, showing that bile‐dependent cell death was a downstream event of Ca2+ signals. Finally, combined application of TLC‐S and the inflammatory mediator bradykinin caused more extensive necrosis in both stellate and acinar cells than TLC‐S alone. Our findings shed new light on the mechanism by which bile acids promote pancreatic pathology. This involves not only signalling in acinar cells but also in stellate cells. PMID:27406326

Biliary lipids, bile acids, and gallbladder function in the human female:effects of contraceptive steroids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kern, F., Jr.; Everson, G.T.; DeMark, B.

Reported are biliary lipid composition and secretion, bile acid composition and kinetics, and gallbladder function in a group of healthy, nonobese women taking a contraceptive steroid preparation. A comparable group of healthy women served as controls. Biliary lipid secretion rate was measured by the marker perfusion technique. Bile acid distribution was determined by gas-lipid chromatography. The pool size, FTR, and synthesis rate of each bile acid were measured by using CA and CDCA labeled with the stable isotope of carbon, /sup 13/C. In some of the subjects gallbladder storage and emptying were measured during the kinetic study, by real-time ultrasonography.more » Contraceptive steroid use was associated with a significant increase in biliary cholesterol saturation and in the lithogenic index of bile. The rate of cholesterol secretion in the contraceptive steroid group was 50% greater than in the control (p << 0.001) and the rate of bile acid secretion was reduced (p < 0.02). The total bile acid pool size was significantly increased by contraceptive steroids. The major increase occurred in the CA pool (p < 0.04). The daily rate of enterohepatic cycles of the bile acid pool was decreased by contraceptive steroids from 6.6 to 4.3 (p < 0.01). The only effect of contraceptive steroids on gallbladder function was a slower emptying rate in response to intraduodenal amino acid infusion. No index of gallbladder function correlated significantly with any parameter of bile acid kinetics in this small group of subjects. The findings confirm the lithogenic effect of contraceptive steroids and indicate that its causes are an increase in cholesterol secretion and a decrease in bile acid secretion.« less

Bile Acid Responses in Methane and Non-Methane Producers to Standard Breakfast Meals

USDA-ARS?s Scientific Manuscript database

Bile acids and their conjugates are important regulators of glucose homeostasis. Previous research has revealed the ratio of cholic acid to deoxycholic acid to affect insulin resistance in humans. Bile acid de-conjugation and intestinal metabolism depend on gut microbes which may be affected by hos...

Beyond Reasonable Doubt: Who Is the Culprit in Lipotoxicity in NAFLD/NASH?

PubMed Central

Arteel, Gavin E.

2016-01-01

BACKGROUND & AIMS Type 2 diabetes and nonalcoholic steatohepatitis (NASH) are associated with insulin resistance and disordered cholesterol homeostasis. We investigated the basis for hepatic cholesterol accumulation with insulin resistance and its relevance to the pathogenesis of NASH. METHODS Alms1 mutant (foz/foz) and wild-type NOD.B10 mice were fed high-fat diets that contained varying percentages of cholesterol; hepatic lipid pools and pathways of cholesterol turnover were determined. Hepatocytes were exposed to insulin concentrations that circulate in diabetic foz/foz mice. RESULTS Hepatic cholesterol accumulation was attributed to up-regulation of low-density lipoprotein receptor via activation of sterol regulatory element binding protein 2 (SREBP-2), reduced biotransformation to bile acids, and suppression of canalicular pathways for cholesterol and bile acid excretion in bile. Exposing primary hepatocytes to concentrations of insulin that circulate in diabetic Alms1 mice replicated the increases in SREBP-2 and low-density lipoprotein receptor and suppression of bile salt export pump. Removing cholesterol from diet prevented hepatic accumulation of free cholesterol and NASH; increasing dietary cholesterol levels exacerbated hepatic accumulation of free cholesterol, hepatocyte injury or apoptosis, macrophage recruitment, and liver fibrosis. CONCLUSIONS In obese, diabetic mice, hyperinsulinemia alters nuclear transcriptional regulators of cholesterol homeostasis, leading to hepatic accumulation of free cholesterol; the resulting cytotoxicity mediates transition of steatosis to NASH. PMID:22422583

Hepatic free cholesterol accumulates in obese, diabetic mice and causes nonalcoholic steatohepatitis.

PubMed

Van Rooyen, Derrick M; Larter, Claire Z; Haigh, W Geoffrey; Yeh, Matthew M; Ioannou, George; Kuver, Rahul; Lee, Sum P; Teoh, Narci C; Farrell, Geoffrey C

2011-10-01

Type 2 diabetes and nonalcoholic steatohepatitis (NASH) are associated with insulin resistance and disordered cholesterol homeostasis. We investigated the basis for hepatic cholesterol accumulation with insulin resistance and its relevance to the pathogenesis of NASH. Alms1 mutant (foz/foz) and wild-type NOD.B10 mice were fed high-fat diets that contained varying percentages of cholesterol; hepatic lipid pools and pathways of cholesterol turnover were determined. Hepatocytes were exposed to insulin concentrations that circulate in diabetic foz/foz mice. Hepatic cholesterol accumulation was attributed to up-regulation of low-density lipoprotein receptor via activation of sterol regulatory element binding protein 2 (SREBP-2), reduced biotransformation to bile acids, and suppression of canalicular pathways for cholesterol and bile acid excretion in bile. Exposing primary hepatocytes to concentrations of insulin that circulate in diabetic Alms1 mice replicated the increases in SREBP-2 and low-density lipoprotein receptor and suppression of bile salt export pump. Removing cholesterol from diet prevented hepatic accumulation of free cholesterol and NASH; increasing dietary cholesterol levels exacerbated hepatic accumulation of free cholesterol, hepatocyte injury or apoptosis, macrophage recruitment, and liver fibrosis. In obese, diabetic mice, hyperinsulinemia alters nuclear transcriptional regulators of cholesterol homeostasis, leading to hepatic accumulation of free cholesterol; the resulting cytotoxicity mediates transition of steatosis to NASH. Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.

Hepatic Free Cholesterol Accumulates in Obese, Diabetic Mice and Causes Non-Alcoholic Steatohepatitis

PubMed Central

Van Rooyen, Derrick M; Larter, Claire Z; Haigh, W Geoffrey; Yeh, Matthew M; Ioannou, George; Kuver, Rahul; Lee, Sum P; Teoh, Narci C; Farrell, Geoffrey C

2011-01-01

Background & Aims Type-2 diabetes and non-alcoholic steatohepatitis (NASH) are associated with insulin resistance and disordered cholesterol homeostasis. We investigated the basis for hepatic cholesterol accumulation with insulin resistance and its relevance to pathogenesis of NASH. Methods Alms1 mutant (foz/foz) and wild-type (WT) NOD.B10 mice were fed high-fat diets that contained varying percentages of cholesterol; hepatic lipid pools and pathways of cholesterol turnover were determined. Hepatocytes were exposed to insulin concentrations that circulate in diabetic foz/foz mice. Results Hepatic cholesterol accumulation was attributed to up-regulation of low density lipoprotein receptor (LDLR) via activation of sterol regulatory element binding protein-2 (SREBP-2), reduced biotransformation to bile acids, and suppression of canalicular pathways for cholesterol and bile acid excretion in bile. Exposing primary hepatocytes to concentrations of insulin that circulate in diabetic Alms1 mice replicated the increases in SREBP-2 and LDLR and suppression of bile salt export pump. Removing cholesterol from diet prevented hepatic accumulation of free cholesterol and NASH; increasing dietary cholesterol exacerbated hepatic accumulation of free cholesterol, hepatocyte injury or apoptosis, macrophage recruitment, and liver fibrosis. Conclusions In obese, diabetic mice, hyperinsulinemia alters nuclear transcriptional regulators of cholesterol homeostasis, leading to hepatic accumulation of free cholesterol; the resulting cytotoxicity mediates transition of steatosis to NASH. PMID:21703998

Genetics Home Reference: congenital bile acid synthesis defect type 1

MedlinePlus

... type 1 Congenital bile acid synthesis defect type 1 Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Congenital bile acid synthesis defect type 1 ...

Physiological and molecular biochemical mechanisms of bile formation

PubMed Central

Reshetnyak, Vasiliy Ivanovich

2013-01-01

This review considers the physiological and molecular biochemical mechanisms of bile formation. The composition of bile and structure of a bile canaliculus, biosynthesis and conjugation of bile acids, bile phospholipids, formation of bile micellar structures, and enterohepatic circulation of bile acids are described. In general, the review focuses on the molecular physiology of the transporting systems of the hepatocyte sinusoidal and apical membranes. Knowledge of physiological and biochemical basis of bile formation has implications for understanding the mechanisms of development of pathological processes, associated with diseases of the liver and biliary tract. PMID:24259965

Deficiency of cholesterol 7α‐hydroxylase in bile acid synthesis exacerbates alcohol‐induced liver injury in mice

PubMed Central

Donepudi, Ajay C.; Ferrell, Jessica M.; Boehme, Shannon; Choi, Hueng‐Sik

2017-01-01

Alcoholic fatty liver disease (AFLD) is a major risk factor for cirrhosis‐associated liver diseases. Studies demonstrate that alcohol increases serum bile acids in humans and rodents. AFLD has been linked to cholestasis, although the physiologic relevance of increased bile acids in AFLD and the underlying mechanism of increasing the bile acid pool by alcohol feeding are still unclear. In this study, we used mouse models either deficient of or overexpressing cholesterol 7α‐hydroxylase (Cyp7a1), the rate‐limiting and key regulatory enzyme in bile acid synthesis, to study the effect of alcohol drinking in liver metabolism and inflammation. Mice were challenged with chronic ethanol feeding (10 days) plus a binge dose of alcohol by oral gavage (5 g/kg body weight). Alcohol feeding reduced bile acid synthesis gene expression but increased the bile acid pool size, hepatic triglycerides and cholesterol, and inflammation and injury in wild‐type mice and aggravated liver inflammation and injury in Cyp7a1‐deficient mice. Interestingly, alcohol‐induced hepatic inflammation and injury were ameliorated in Cyp7a1 transgenic mice. Conclusion: Alcohol feeding alters hepatic bile acid and cholesterol metabolism to cause liver inflammation and injury, while maintenance of bile acid and cholesterol homeostasis protect against alcohol‐induced hepatic inflammation and injury. Our findings indicate that CYP7A1 plays a key role in protection against alcohol‐induced steatohepatitis. (Hepatology Communications 2018;2:99–112) PMID:29404516

H. pylori in the pathogenesis of duodenal ulcer: interaction between duodenal acid load, bile, and H. pylori.

PubMed

Graham, D Y; Osato, M S

2000-01-01

Helicobacter pylori (H. pylori) growth is inhibited by bile yet it can grow in the duodenal bulb and cause ulcer disease. The aim of this study was to test the effect of bile on H. pylori viability and growth and to determine whether acidification of bile reduces its inhibitory activity. Fresh human bile was collected at laparotomy and tested for inhibitory activity of H. pylori using broth dilution assays. Six clinical isolates of H. pylori obtained from patients with duodenal ulcer were used for each experiment. The bile was diluted from 1:3 to 1:192; its inhibitory effect on H. pylori was tested before and after acidification, treatment with cholestyramine, or chloroform. Bile was acidified to a pH of 2-6, centrifuged at 8000 rpm for 20 min to remove precipitated bile acids, and the supernatant pH readjusted. Controls included BHI broth without bile (positive control) and bile that was acidified to pH 2 and neutralized without centrifugation. Human bile inhibited H. pylori growth in a dose dependent manner. Growth of all strains was supported for all strains only at a dilution of 1:192. In contrast, after acidification to pH < or =5 and centrifugation to remove precipitated bile acids, all strains grew at a bile dilution of 1:12. Neither chloroform extraction of lipids, nor acidification without centrifugation removed the inhibitory action of bile. In contrast, cholestyramine sequestration of bile acids completely removed all inhibitory activity. The duodenal acid load may be the critical factor to explain the ability of H. pylori to colonize the duodenal bulb by precipitating glycine-conjugated bile salts. The combination of a high duodenal acid load and H. pylori infection is likely the critical event in the pathogenesis of H. pylori-related duodenal ulcer disease.

Preparation of the 3-monosulphates of cholic acid, chenodeoxycholic acid and deoxycholic acid.

PubMed Central

Haslewood, E S; Haslewood, G A

1976-01-01

1. The 3-sulphates of cholic, chenodeoxycholic and deoxycholic acids were prepared as crystalline disodium salts. 2. The method described shows that it is possible to prepare specific sulphate esters of polyhydroxy bile acids and to remove protecting acyl groups without removing the sulphate. 3. A study of bile acid sulphate solvolysis showed that none of the usual methods give the original bile acid in major yield in a single step. 4. An understanding of the preparation, properties and methods of solvolysis of bile acid sulphates is basic for investigations of cholestasis and liver disease. PMID:938488

Bile acid regulates c-Jun expression through the orphan nuclear receptor SHP induction in gastric cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Won Il; Park, Min Jung; An, Jin Kwang

2008-05-02

Bile reflux is considered to be one of the most important causative factors in gastric carcinogenesis, due to the attendant inflammatory changes in the gastric mucosa. In this study, we have assessed the molecular mechanisms inherent to the contribution of bile acid to the transcriptional regulation of inflammatory-related genes. In this study, we demonstrated that bile acid induced the expression of the SHP orphan nuclear receptor at the transcriptional level via c-Jun activation. Bile acid also enhanced the protein interaction of NF-{kappa}B and SHP, thereby resulting in an increase in c-Jun expression and the production of the inflammatory cytokine, TNF{alpha}.more » These results indicate that bile acid performs a critical function in the regulation of the induction of inflammatory-related genes in gastric cells, and that bile acid-mediated gene expression provides a pre-clue for the development of gastric cellular malformation.« less

Bile acid malabsorption in Crohn's disease and indications for its assessment using SeHCAT.

PubMed

Nyhlin, H; Merrick, M V; Eastwood, M A

1994-01-01

Patients with Crohn's disease who suffer from longstanding diarrhoea that does not respond to conventional treatment pose a common clinical problem. Bile acid malabsorption is a possible cause, although its prevalence and clinical importance is unclear. This paper explores the clinical indications for referring patients with Crohn's disease for bile acid assessment and the extent of bile acid malabsorption in this selected group of patients. The selenium labelled bile acid SeHCAT was used to assess the effect of disease on the integrity of the enterohepatic circulation. Altogether 76% of the patients referred for bile acid assessment had longstanding diarrhoea that had not responded to conventional anti-diarrhoeal treatment or an increase in steroid therapy as their sole or predominant symptom. Ninety per cent of patients with bowel resections, almost exclusively ileocaecal, had abnormal SeHCAT retention (< 5% at seven days). Twenty eight per cent of patients with Crohn's disease who had not undergone resection 28% had a SeHCAT retention < 5%, signifying bile acid malabsorption. Nineteen of 22 patients given cholestyramine treatment subsequent to the SeHCAT test had a good symptomatic response. In conclusion, the prevalence of bile acid malabsorption in this selected group with Crohn's disease is sufficiently high to justify performing the SeHCAT test in order to separate the various differential diagnoses.

Topochemical approach to efficiently produce main-chain poly(bile acid)s with high molecular weights.

PubMed

Li, Weina; Li, Xuesong; Zhu, Wei; Li, Changxu; Xu, Dan; Ju, Yong; Li, Guangtao

2011-07-21

Based on a topochemical approach, a strategy for efficiently producing main-chain poly(bile acid)s in the solid state was developed. This strategy allows for facile and scalable synthesis of main-chain poly(bile acid)s not only with high molecular weights, but also with quantitative conversions and yields.

Recycling rate of bile acids in the enterohepatic recirculation as a major determinant of whole body 75SeHCAT retention.

PubMed

Peters, A Michael; Walters, Julian R F

2013-10-01

Measurement of the whole body retention of orally administered (75)SeHCAT is used to investigate patients with unexplained diarrhoea. Retention values of <15 % at 7 days post-administration are taken to indicate bile acid malabsorption (BAM). Whilst idiopathic BAM is frequently diagnosed with (75)SeHCAT, functional and morphological studies of the terminal ileum rarely show any abnormality, so the disorder may be more appropriately termed bile acid diarrhoea (BAD). In addition to malabsorption, excess bile acid may reach the colon, where the events leading to diarrhoea take place, as a result firstly of increased bile acid synthesis and secondly of an increased recycling rate of bile acids. Increased recycling has been largely ignored as a cause of BAD, but, as shown in this study, can readily result in excess bile acids reaching the colon even when ileal absorption efficiency is normal (i.e. 95-97 %). There needs to be a re-evaluation of the causes of BAD in patients without a history of previous intestinal resection or evidence of ileal pathology, such as Crohn's disease.

Impact of microbial derived secondary bile acids on colonization resistance against Clostridium difficile in the gastrointestinal tract.

PubMed

Winston, Jenessa A; Theriot, Casey M

2016-10-01

Clostridium difficile is an anaerobic, Gram positive, spore-forming bacillus that is the leading cause of nosocomial gastroenteritis. Clostridium difficile infection (CDI) is associated with increasing morbidity and mortality, consequently posing an urgent threat to public health. Recurrence of CDI after successful treatment with antibiotics is high, thus necessitating discovery of novel therapeutics against this pathogen. Susceptibility to CDI is associated with alterations in the gut microbiota composition and bile acid metabolome, specifically a loss of microbial derived secondary bile acids. This review aims to summarize in vitro, ex vivo, and in vivo studies done by our group and others that demonstrate how secondary bile acids affect the different stages of the C. difficile life cycle. Understanding the dynamic interplay of C. difficile and microbial derived secondary bile acids within the gastrointestinal tract will shed light on how bile acids play a role in colonization resistance against C. difficile. Rational manipulation of secondary bile acids may prove beneficial as a treatment for patients with CDI. Published by Elsevier Ltd.

Clinical Study of Ursodeoxycholic Acid in Barrett’s Esophagus Patients

PubMed Central

Banerjee, Bhaskar; Shaheen, Nicholas J.; Martinez, Jessica A.; Hsu, Chiu-Hsieh; Trowers, Eugene; Gibson, Blake A.; Della’Zanna, Gary; Richmond, Ellen; Chow, H-H. Sherry

2016-01-01

Prior research strongly implicates gastric acid and bile acids, two major components of the gastroesophageal refluxate, in the development of Barrett’s esophagus (BE) and its pathogenesis. Ursodeoxycholic acid (UDCA), a hydrophilic bile acid, has been shown to protect esophageal cells against oxidative stress induced by cytotoxic bile acids. We conducted a pilot clinical study to evaluate the clinical activity of UDCA in patients with BE. Twenty-nine BE patients received UDCA treatment at a daily dose of 13–15 mg/kg/day for six months. The clinical activity of UDCA was assessed by evaluating changes in gastric bile acid composition and markers of oxidative DNA damage (8-hydroxydeoxyguanosine, 8OHdG), cell proliferation (Ki67), and apoptosis (cleaved caspase 3, CC3) in BE epithelium. The bile acid concentrations in gastric fluid were measured by liquid chromatography-mass spectrometry. At baseline, UDCA (sum of unchanged and glycine/taurine conjugates) accounted for 18.2% of total gastric bile acids. Post UDCA intervention, UDCA increased significantly to account for 93.39% of total gastric bile acids (p<0.0001). The expression of markers of oxidative DNA damage, cell proliferation, and apoptosis was assessed in the BE biopsies by immunohistochemistry. The selected tissue biomarkers were unchanged after 6 months of UDCA intervention. We conclude that high dose UDCA supplementation for six months resulted in favorable changes in gastric bile acid composition but did not modulate selected markers of oxidative DNA damage, cell proliferation, and apoptosis in the BE epithelium. PMID:26908564

Bile acid aspiration in suspected ventilator-associated pneumonia.

PubMed

Wu, Yu-Chung; Hsu, Po-Kuei; Su, Kang-Cheng; Liu, Lung-Yu; Tsai, Cheng-Chien; Tsai, Shu-Ho; Hsu, Wen-Hu; Lee, Yu-Chin; Perng, Diahn-Warng

2009-07-01

The aims of this study were to measure the levels of bile acids in patients with suspected ventilator-associated pneumonia (VAP) and provide a possible pathway for neutrophilic inflammation to explain its proinflammatory effect on the airway. Bile acid levels were measured by spectrophotometric enzymatic assay, and liquid chromatography mass spectrometry was used to quantify the major bile acids. Alveolar cells were grown on modified air-liquid interface culture inserts, and bile acids were then employed to stimulate the cells. Reverse transcriptase polymerase chain reaction and Western blots were used to determine the involved gene expression and protein levels. The mean (+/- SE) concentration of total bile acids in tracheal aspirates was 6.2 +/- 2.1 and 1.1 +/- 0.4 mumol/L/g sputum, respectively, for patients with and without VAP (p < 0.05). The interleukin (IL)-8 level was significantly higher in the VAP group (p < 0.05). The major bile acid, chenodeoxycholic acid, stimulated alveolar epithelial cells to increase IL-8 production at both the messenger RNA and protein level through p38 and c-Jun N-terminal kinase (JNK) activation. The selective p38 and JNK inhibitors, as well as dexamethasone, successfully inhibited IL-8 production. These data suggest that early intervention to prevent bile acid aspiration may reduce the intensity of neutrophilic inflammation in intubated and mechanically ventilated patients in the ICU.

Effect of ursodeoxycholic acid treatment on the altered progesterone and bile acid homeostasis in the mother-placenta-foetus trio during cholestasis of pregnancy

PubMed Central

Estiú, Maria C; Monte, Maria J; Rivas, Laura; Moirón, Maria; Gomez-Rodriguez, Laura; Rodriguez-Bravo, Tomas; Marin, Jose JG; Macias, Rocio IR

2015-01-01

Aim Intrahepatic cholestasis of pregnancy (ICP) is characterized by pruritus and elevated bile acid concentrations in maternal serum. This is accompanied by an enhanced risk of intra-uterine and perinatal complications. High concentrations of sulphated progesterone metabolites (PMS) have been suggested to be involved in the multifactorial aetiopathogenesis of ICP. The aim of this study was to investigate further the mechanism accounting for the beneficial effect of oral administration of ursodeoxycholic acid (UDCA), which is the standard treatment, regarding bile acid and PMS homeostasis in the mother-placenta-foetus trio. Method Using HPLC-MS/MS bile acids and PMS were determined in maternal and foetal serum and placenta. The expression of ABC proteins in placenta was determined by real time quantitative PCR (RT-QPCR) and immunofluorescence. Results In ICP, markedly increased concentrations of bile acids (tauroconjugates > glycoconjugates >> unconjugated), progesterone and PMS in placenta and maternal serum were accompanied by enhanced concentrations in foetal serum of bile acids, but not of PMS. UDCA treatment reduced bile acid accumulation in the mother-placenta-foetus trio, but had no significant effect on progesterone and PMS concentrations. ABCG2 mRNA abundance was increased in placentas from ICP patients vs. controls and remained stable following UDCA treatment, despite an apparent further increase in ABCG2. Conclusion UDCA administration partially reduces ICP-induced bile acid accumulation in mothers and foetuses despite the lack of effect on concentrations of progesterone and PMS in maternal serum. Up-regulation of placental ABCG2 may play an important role in protecting the foetus from high concentrations of bile acids and PMS during ICP. PMID:25099365

Effect of ursodeoxycholic acid treatment on the altered progesterone and bile acid homeostasis in the mother-placenta-foetus trio during cholestasis of pregnancy.

PubMed

Estiú, Maria C; Monte, Maria J; Rivas, Laura; Moirón, Maria; Gomez-Rodriguez, Laura; Rodriguez-Bravo, Tomas; Marin, Jose J G; Macias, Rocio I R

2015-02-01

Intrahepatic cholestasis of pregnancy (ICP) is characterized by pruritus and elevated bile acid concentrations in maternal serum. This is accompanied by an enhanced risk of intra-uterine and perinatal complications. High concentrations of sulphated progesterone metabolites (PMS) have been suggested to be involved in the multifactorial aetiopathogenesis of ICP. The aim of this study was to investigate further the mechanism accounting for the beneficial effect of oral administration of ursodeoxycholic acid (UDCA), which is the standard treatment, regarding bile acid and PMS homeostasis in the mother-placenta-foetus trio. Using HPLC-MS/MS bile acids and PMS were determined in maternal and foetal serum and placenta. The expression of ABC proteins in placenta was determined by real time quantitative PCR (RT-QPCR) and immunofluorescence. In ICP, markedly increased concentrations of bile acids (tauroconjugates > glycoconjugates > unconjugated), progesterone and PMS in placenta and maternal serum were accompanied by enhanced concentrations in foetal serum of bile acids, but not of PMS. UDCA treatment reduced bile acid accumulation in the mother-placenta-foetus trio, but had no significant effect on progesterone and PMS concentrations. ABCG2 mRNA abundance was increased in placentas from ICP patients vs. controls and remained stable following UDCA treatment, despite an apparent further increase in ABCG2. UDCA administration partially reduces ICP-induced bile acid accumulation in mothers and foetuses despite the lack of effect on concentrations of progesterone and PMS in maternal serum. Up-regulation of placental ABCG2 may play an important role in protecting the foetus from high concentrations of bile acids and PMS during ICP. © 2014 The British Pharmacological Society.

Herbert Falk: a vital force in the renaissance of bile acid research and bile acid therapy.

PubMed

Hofmann, Alan F

2011-01-01

Herbert Falk died on August 8, 2008, after a long illness. It was his vision that initiated the Bile Acid Meetings and brought to market chenodeoxycholic acid and ursodeoxycholic acid for the dissolution of cholesterol gallstones as well as the successful treatment of cholestatic liver disease. The 1st Bile Acid Meeting was a small workshop held at the University Hospital of Freiburg in 1970. Great interest in the topic was evident at that small meeting and led to a larger meeting in 1972, whose scope included both the basic and clinical aspects of bile acids. These meetings have continued at biennial intervals, the 2010 meeting being the 21st. The program has always included discussions of the most fundamental aspects of bile acid biosynthesis and metabolism as well as clinical applications of bile acid therapy. The meetings featured brief presentations, ample time for discussion, and imaginative social programs. They have always been flawlessly organized. Social programs usually included a hike through the beautiful countryside of the Black Forest followed by dinner in a rustic restaurant. Herbert Falk took part in these programs, personally welcoming every participant. In the warm glow of the 'Badische' hospitality, friendships developed, and scientific collaborations were often arranged. From a scientific standpoint, there has been enormous progress in understanding the chemistry and biology of bile acids. Herbert Falk established the Windaus Prize in 1978, and the prize has been given to individuals whose contributions moved the field forward. These bile acid meetings have been marvelous, rewarding experiences. We must all be grateful to Herbert Falk's vision in establishing the Falk Foundation that has so generously sponsored these meetings. We also express our gratitude to his widow, Ursula Falk, who continues this worthy tradition. Copyright © 2011 S. Karger AG, Basel.

Intestinal bile acid malabsorption in cystic fibrosis.

PubMed

O'Brien, S; Mulcahy, H; Fenlon, H; O'Broin, A; Casey, M; Burke, A; FitzGerald, M X; Hegarty, J E

1993-08-01

This study aimed at examining the mechanisms participating in excessive faecal bile acid loss in cystic fibrosis. The study was designed to define the relation between faecal fat and faecal bile acid loss in patients with and without cystic fibrosis related liver disease; to assess terminal ileal bile acid absorption by a seven day whole body retention of selenium labelled homotaurocholic acid (SeHCAT); and to determine if small intestinal bacterial overgrowth contributes to faecal bile acid loss. The study population comprised 40 patients (27 men; median age 18 years) with cystic fibrosis (n = 8) and without (n = 32) liver disease and eight control subjects. Faecal bile acid excretion was significantly higher in cystic fibrosis patients without liver disease compared with control subjects (mean (SEM) 21.5 (2.4) and 7.3 (1.2) micromoles/kg/24 hours respectively; p < 0.01) and patients with liver disease (7.9 (1.3) micromoles/kg/24 hours; p < 0.01). No correlation was found between faecal fat (g fat/24 hours) and faecal bile acid (micromoles 24 hours) excretion. Eight (33%) of cystic fibrosis patients had seven day SeHCAT retention < 10% (normal retention > 20%). SeHCAT retention in cystic fibrosis patients with liver disease was comparable with control subjects (30.0 (SEM) 8.3% v 36.8 (5.9)%; p = NS) while SeHCAT retention in cystic fibrosis patients who did not have liver disease was significantly reduced (19.9 (3.8); p < 0.05). Although evidence of small bowel bacterial overgrowth was present in 40% of patients no relation was found between breath hydrogen excretion, faecal fat, and faecal bile acid loss. The results are consistent with the presence of an abnormality in terminal ideal function in patients with cystic fibrosis who do not have liver disease and that a defect in the ileal absorption of bile acids may be a contributory factor to excessive faecal bile acid loss. Faecal bile acid loss in cystic fibrosis is unrelated to the presence of intraluminal fat or intestinal bacterial overgrowth.

Intestinal bile acid malabsorption in cystic fibrosis.

PubMed Central

O'Brien, S; Mulcahy, H; Fenlon, H; O'Broin, A; Casey, M; Burke, A; FitzGerald, M X; Hegarty, J E

1993-01-01

This study aimed at examining the mechanisms participating in excessive faecal bile acid loss in cystic fibrosis. The study was designed to define the relation between faecal fat and faecal bile acid loss in patients with and without cystic fibrosis related liver disease; to assess terminal ileal bile acid absorption by a seven day whole body retention of selenium labelled homotaurocholic acid (SeHCAT); and to determine if small intestinal bacterial overgrowth contributes to faecal bile acid loss. The study population comprised 40 patients (27 men; median age 18 years) with cystic fibrosis (n = 8) and without (n = 32) liver disease and eight control subjects. Faecal bile acid excretion was significantly higher in cystic fibrosis patients without liver disease compared with control subjects (mean (SEM) 21.5 (2.4) and 7.3 (1.2) micromoles/kg/24 hours respectively; p < 0.01) and patients with liver disease (7.9 (1.3) micromoles/kg/24 hours; p < 0.01). No correlation was found between faecal fat (g fat/24 hours) and faecal bile acid (micromoles 24 hours) excretion. Eight (33%) of cystic fibrosis patients had seven day SeHCAT retention < 10% (normal retention > 20%). SeHCAT retention in cystic fibrosis patients with liver disease was comparable with control subjects (30.0 (SEM) 8.3% v 36.8 (5.9)%; p = NS) while SeHCAT retention in cystic fibrosis patients who did not have liver disease was significantly reduced (19.9 (3.8); p < 0.05). Although evidence of small bowel bacterial overgrowth was present in 40% of patients no relation was found between breath hydrogen excretion, faecal fat, and faecal bile acid loss. The results are consistent with the presence of an abnormality in terminal ideal function in patients with cystic fibrosis who do not have liver disease and that a defect in the ileal absorption of bile acids may be a contributory factor to excessive faecal bile acid loss. Faecal bile acid loss in cystic fibrosis is unrelated to the presence of intraluminal fat or intestinal bacterial overgrowth. PMID:8174969

Modification on ursodeoxycholic acid (UDCA) scaffold. discovery of bile acid derivatives as selective agonists of cell-surface G-protein coupled bile acid receptor 1 (GP-BAR1).

PubMed

Sepe, Valentina; Renga, Barbara; Festa, Carmen; D'Amore, Claudio; Masullo, Dario; Cipriani, Sabrina; Di Leva, Francesco Saverio; Monti, Maria Chiara; Novellino, Ettore; Limongelli, Vittorio; Zampella, Angela; Fiorucci, Stefano

2014-09-25

Bile acids are signaling molecules interacting with the nuclear receptor FXR and the G-protein coupled receptor 1 (GP-BAR1/TGR5). GP-BAR1 is a promising pharmacological target for the treatment of steatohepatitis, type 2 diabetes, and obesity. Endogenous bile acids and currently available semisynthetic bile acids are poorly selective toward GP-BAR1 and FXR. Thus, in the present study we have investigated around the structure of UDCA, a clinically used bile acid devoid of FXR agonist activity, to develop a large family of side chain modified 3α,7β-dihydroxyl cholanoids that selectively activate GP-BAR1. In vivo and in vitro pharmacological evaluation demonstrated that administration of compound 16 selectively increases the expression of pro-glucagon 1, a GP-BAR1 target, in the small intestine, while it had no effect on FXR target genes in the liver. Further, compound 16 results in a significant reshaping of bile acid pool in a rodent model of cholestasis. These data demonstrate that UDCA is a useful scaffold to generate novel and selective steroidal ligands for GP-BAR1.

Characteristics of lipid substances activating the ileal brake in the rat.

PubMed Central

Brown, N J; Read, N W; Richardson, A; Rumsey, R D; Bogentoft, C

1990-01-01

Studies were carried out in 36 adult male rats to determine the characteristics of lipid substances which, after infusion into the ileum, slow the stomach to caecum transit time of the head of a bean meal in the rat. Stomach to caecum transit time was measured by environmental hydrogen analysis. Ileal infusion of a range of free fatty acids including petroselinic, oleic, myristoleic, erucic, linoleic, and linolenic all significantly slowed stomach to caecum transit time, as did the detergents (sodium bis (2-ethyl hexyl) sulphosuccinate and sodium linoleyl sulphate), the triglyceride corn oil, and the phospholipid lecithin. Although the lipid soluble deconjugated bile acid deoxycholic acid slowed stomach to caecum transit time, the water soluble conjugated bile acid taurocholic acid accelerated it. Infusion of the lipid alcohol oleyl alcohol and the calcium chelating agent disodium edetate (EDTA) into the ileum did not delay the passage of the meal through the stomach and small intestine. The diversity of lipid substances activating the ileal brake suggest a nonspecific effect by lipid soluble substances that can penetrate cell membranes. The lack of effect of EDTA suggested that calcium binding was not important. PMID:2128071

Bile alcohols function as the ligands of membrane-type bile acid-activated G protein-coupled receptor

PubMed Central

Iguchi, Yusuke; Yamaguchi, Masafumi; Sato, Hiroyuki; Kihira, Kenji; Nishimaki-Mogami, Tomoko; Une, Mizuho

2010-01-01

TGR5 is a G protein-coupled receptor that is activated by bile acids, resulting in an increase in cAMP levels and the subsequent modulation of energy expenditure in brown adipose tissue and muscle. Therefore, the development of a TGR5-specific agonist could lead to the prevention and treatment of various metabolic disorders related to obesity. In the present study, we evaluated the ability of bile alcohols, which are structurally and physiologically similar to bile acids and are produced as the end products of cholesterol catabolism in evolutionarily primitive vertebrates, to act as TGR5 agonists. In a cell-based reporter assay and a cAMP production assay performed in vitro, most bile alcohols with a side chain containing hydroxyl group(s) were highly efficacious agonists for TGR5 comparable to its most potent ligand in the naturally occurring bile acid, lithocholic acid. However, the abilities of the bile alcohols to activate TGR5 varied with the position and number of the hydroxyl substituent in the side chain. Additionally, the conformation of the steroidal nucleus of bile alcohols is also important for its activity as a TGR5 agonist. Thus, we have provided new insights into the structure-activity relationships of bile alcohols as TGR5 agonists. PMID:20023205

Fibroblast growth factor 19 in patients with bile acid diarrhoea: a prospective comparison of FGF19 serum assay and SeHCAT retention.

PubMed

Pattni, S S; Brydon, W G; Dew, T; Johnston, I M; Nolan, J D; Srinivas, M; Basumani, P; Bardhan, K D; Walters, J R F

2013-10-01

Bile acid diarrhoea is a common, under-diagnosed cause of chronic watery diarrhoea, responding to specific treatment with bile acid sequestrants. We previously showed patients with bile acid diarrhoea have lower median levels compared with healthy controls, of the ileal hormone fibroblast growth factor 19 (FGF19), which regulates bile acid synthesis. To measure serum FGF19 and SeHCAT retention prospectively in patients with chronic diarrhoea. One hundred and fifty-two consecutive patients were grouped according to (75) Se-homocholic acid taurine (SeHCAT) 7-day retention: normal (>15%) in 72 (47%) diarrhoea controls; ≤15% in 54 (36%) with primary bile acid diarrhoea, and in 26 (17%) with secondary bile acid diarrhoea. Fasting blood was assayed for FGF19, 7α-hydroxy-4-cholesten-3-one (C4) and total bile acids. FGF19 was significantly lower in the primary bile acid diarrhoea group compared with the diarrhoea control group (median 147 vs. 225 pg/mL, P < 0.001), and also in the secondary group (P < 0.006). FGF19 and SeHCAT values were positively correlated (rs = 0.44, P < 0.001); both were inversely related to C4. Other significant relationships included SeHCAT and body mass index (BMI)(P = 0.02), and FGF19 with age (P < 0.01). The negative and positive predictive values of FGF19 ≤ 145 pg/mL for a SeHCAT <10% were 82% and 61%, respectively, and were generally improved in an index including BMI, age and C4. In a subset of 28 primary patients, limited data suggested that FGF19 could predict response to sequestrant therapy. Reduced fibroblast growth factor 19 is a feature of bile acid diarrhoea. Further studies will fully define its role in predicting the response of these patients to therapy. © 2013 John Wiley & Sons Ltd.

Radiosynthesis of N-¹¹C-Methyl-Taurine-Conjugated Bile Acids and Biodistribution Studies in Pigs by PET/CT.

PubMed

Schacht, Anna Christina; Sørensen, Michael; Munk, Ole Lajord; Frisch, Kim

2016-04-01

During cholestasis, accumulation of conjugated bile acids may occur in the liver and lead to hepatocellular damage. Inspired by our recent development of N-(11)C-methyl-glycocholic acid-that is, (11)C-cholylsarcosine-a tracer for PET of the endogenous glycine conjugate of cholic acid, we report here a radiosynthesis of N-(11)C-methyl-taurine-conjugated bile acids and biodistribution studies in pigs by PET/CT. A radiosynthesis of N-(11)C-methyl-taurine-conjugated bile acids was developed and used to prepare N-(11)C-methyl-taurine conjugates derived from cholic, chenodeoxycholic, deoxycholic, ursodeoxycholic, and lithocholic acid. The lipophilicity of these new tracers was determined by reversed-phase thin-layer chromatography. The effect of lipophilicity and structure on the biodistribution was investigated in pigs by PET/CT using the tracers derived from cholic acid (3α-OH, 7α-OH, 12α-OH), ursodeoxycholic acid (3α-OH, 7β-OH), and lithocholic acid (3α-OH). The radiosyntheses of the N-(11)C-methyl-taurine-conjugated bile acids proceeded with radiochemical yields of 61% (decay-corrected) or greater and radiochemical purities greater than 99%. PET/CT in pigs revealed that the tracers were rapidly taken up by the liver and secreted into bile. There was no detectable radioactivity in urine. Significant reflux of N-(11)C-methyl-taurolithocholic acid into the stomach was observed. We have successfully developed a radiosynthesis of N-(11)C-methyl-taurine-conjugated bile acids. These tracers behave in a manner similar to endogenous taurine-conjugated bile acids in vivo and are thus promising for functional PET of patients with cholestatic diseases. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Effects of conventional and a novel colonic-release bile acid sequestrant, A3384, on fibroblast growth factor 19 and bile acid metabolism in healthy volunteers and patients with bile acid diarrhoea.

PubMed

Appleby, R N; Bajor, A; Gillberg, P-G; Graffner, H; Simrén, M; Ung, K A; Walters, Jrf

2017-04-01

Primary bile acid diarrhoea (BAD) is associated with increased bile acid synthesis and low fibroblast growth factor 19 (FGF19). Bile acid sequestrants are used as therapy, but are poorly tolerated and may exacerbate FGF19 deficiency. The purpose of this study was to evaluate the pharmacological effects of conventional sequestrants and a colonic-release formulation preparation of colestyramine (A3384) on bile acid metabolism and bowel function in patients with BAD. Patients with seven-day 75 selenium-homocholic acid taurine (SeHCAT) scan retention <10% were randomised in a double-blind protocol to two weeks treatment with twice-daily A3384 250 mg ( n  = 6), 1 g ( n  = 7) or placebo ( n  = 6). Thirteen patients were taking conventional sequestrants at the start of the study. Symptoms were recorded and serum FGF19 and 7α-hydroxy-4-cholesten-3-one (C4) measured. Median serum FGF19 on conventional sequestrant treatment was 28% lower than baseline values in BAD ( p  < 0.05). C4 on conventional sequestrant treatment was 58% higher in BAD ( p  < 0.001). No changes were seen on starting or withdrawing A3384. A3384 improved diarrhoeal symptoms, with a median reduction of 2.2 points on a 0-10 Likert scale compared to placebo, p  < 0.05. Serum FGF19 was suppressed and bile acid production up-regulated on conventional bile acid sequestrants, but not with A3384. This colonic-release formulation of colestyramine produced symptomatic benefit in patients with BAD.

Effects of conventional and a novel colonic-release bile acid sequestrant, A3384, on fibroblast growth factor 19 and bile acid metabolism in healthy volunteers and patients with bile acid diarrhoea

PubMed Central

Bajor, A; Gillberg, P-G; Graffner, H; Simrén, M; Ung, KA; Walters, JRF

2016-01-01

Background Primary bile acid diarrhoea (BAD) is associated with increased bile acid synthesis and low fibroblast growth factor 19 (FGF19). Bile acid sequestrants are used as therapy, but are poorly tolerated and may exacerbate FGF19 deficiency. Aim The purpose of this study was to evaluate the pharmacological effects of conventional sequestrants and a colonic-release formulation preparation of colestyramine (A3384) on bile acid metabolism and bowel function in patients with BAD. Methods Patients with seven-day 75selenium-homocholic acid taurine (SeHCAT) scan retention <10% were randomised in a double-blind protocol to two weeks treatment with twice-daily A3384 250 mg (n = 6), 1 g (n = 7) or placebo (n = 6). Thirteen patients were taking conventional sequestrants at the start of the study. Symptoms were recorded and serum FGF19 and 7α-hydroxy-4-cholesten-3-one (C4) measured. Results Median serum FGF19 on conventional sequestrant treatment was 28% lower than baseline values in BAD (p < 0.05). C4 on conventional sequestrant treatment was 58% higher in BAD (p < 0.001). No changes were seen on starting or withdrawing A3384. A3384 improved diarrhoeal symptoms, with a median reduction of 2.2 points on a 0–10 Likert scale compared to placebo, p < 0.05. Conclusions Serum FGF19 was suppressed and bile acid production up-regulated on conventional bile acid sequestrants, but not with A3384. This colonic-release formulation of colestyramine produced symptomatic benefit in patients with BAD. PMID:28507750

Mice with chimeric livers are an improved model for human lipoprotein metabolism.

PubMed

Ellis, Ewa C S; Naugler, Willscott Edward; Nauglers, Scott; Parini, Paolo; Mörk, Lisa-Mari; Jorns, Carl; Zemack, Helen; Sandblom, Anita Lövgren; Björkhem, Ingemar; Ericzon, Bo-Göran; Wilson, Elizabeth M; Strom, Stephen C; Grompe, Markus

2013-01-01

Rodents are poor model for human hyperlipidemias because total cholesterol and low density lipoprotein levels are very low on a normal diet. Lipoprotein metabolism is primarily regulated by hepatocytes and we therefore assessed whether chimeric mice extensively repopulated with human cells can model human lipid and bile acid metabolism. FRG [ F ah(-/-) R ag2(-/-)Il2r g (-/-)]) mice were repopulated with primary human hepatocytes. Serum lipoprotein lipid composition and distribution (VLDL, LDL, and HDL) was analyzed by size exclusion chromatography. Bile was analyzed by LC-MS or by GC-MS. RNA expression levels were measured by quantitative RT-PCR. Chimeric mice displayed increased LDL and VLDL fractions and a lower HDL fraction compared to wild type, thus significantly shifting the ratio of LDL/HDL towards a human profile. Bile acid analysis revealed a human-like pattern with high amounts of cholic acid and deoxycholic acid (DCA). Control mice had only taurine-conjugated bile acids as expcted, but highly repopulated mice had glycine-conjugated cholic acid as found in human bile. RNA levels of human genes involved in bile acid synthesis including CYP7A1, and CYP27A1 were significantly upregulated as compared to human control liver. However, administration of recombinant hFGF19 restored human CYP7A1 levels to normal. Humanized-liver mice showed a typical human lipoprotein profile with LDL as the predominant lipoprotein fraction even on a normal diet. The bile acid profile confirmed presence of an intact enterohepatic circulation. Although bile acid synthesis was deregulated in this model, this could be fully normalized by FGF19 administration. Taken together these data indicate that chimeric FRG-mice are a useful new model for human lipoprotein and bile-acid metabolism.

Bile acid malabsorption in Crohn's disease and indications for its assessment using SeHCAT.

PubMed Central

Nyhlin, H; Merrick, M V; Eastwood, M A

1994-01-01

Patients with Crohn's disease who suffer from longstanding diarrhoea that does not respond to conventional treatment pose a common clinical problem. Bile acid malabsorption is a possible cause, although its prevalence and clinical importance is unclear. This paper explores the clinical indications for referring patients with Crohn's disease for bile acid assessment and the extent of bile acid malabsorption in this selected group of patients. The selenium labelled bile acid SeHCAT was used to assess the effect of disease on the integrity of the enterohepatic circulation. Altogether 76% of the patients referred for bile acid assessment had longstanding diarrhoea that had not responded to conventional anti-diarrhoeal treatment or an increase in steroid therapy as their sole or predominant symptom. Ninety per cent of patients with bowel resections, almost exclusively ileocaecal, had abnormal SeHCAT retention (< 5% at seven days). Twenty eight per cent of patients with Crohn's disease who had not undergone resection 28% had a SeHCAT retention < 5%, signifying bile acid malabsorption. Nineteen of 22 patients given cholestyramine treatment subsequent to the SeHCAT test had a good symptomatic response. In conclusion, the prevalence of bile acid malabsorption in this selected group with Crohn's disease is sufficiently high to justify performing the SeHCAT test in order to separate the various differential diagnoses. PMID:8307458

Effects of dose, flow rate, and bile acid on diclofenac disposition in the perfused rat liver.

PubMed

Uraki, Misato; Kawase, Atsushi; Matsushima, Yuka; Iwaki, Masahiro

2016-06-01

An in situ perfused rat liver system is useful for studying the hepatic disposition of drugs and their metabolites. However, the effects of the perfusion conditions on drug disposition are unclear. We examined the effects of conditions such as flow rate (13 or 26 mL/min) and bile acid on disposition of diclofenac (DF) as a model drug and DF metabolites [diclofenac-1-O-acyl glucuronide (DF-Glu) or 4'-hydroxydiclofenac (DF-4'OH)] in the absence of albumin. DF, DF-Glu, and DF-4'OH concentrations in the perfusate and cumulative amounts of DF-Glu excreted in bile were measured using high-performance liquid chromatography methods. DF in the perfusate was rapidly eliminated as the perfusate flow rate increased. The area under the plasma concentration-time curve from 0 to 60 min (AUC0-60) for DF-Glu and DF-4'OH in a perfusate containing bile acid was lower at a flow rate of 26 and 13 mL/min, respectively. The bile flow rate at 26 mL/min with 24 μM of bile acid in the perfusate was significantly higher (ca. 3.5 times) compared with that at 13 mL/min without bile acid. Cumulative biliary DF-Glu excretion was also dramatically affected by the flow rate and addition of bile acid. This study indicated that the flow rate and bile acid in the perfused rat liver were key factors for bile flow rate and DF, DF-Glu, and DF-4'OH disposition in the absence of albumin.

Potential human cholesterol esterase inhibitor design: benefits from the molecular dynamics simulations and pharmacophore modeling studies.

PubMed

John, Shalini; Thangapandian, Sundarapandian; Lee, Keun Woo

2012-01-01

Human pancreatic cholesterol esterase (hCEase) is one of the lipases found to involve in the digestion of large and broad spectrum of substrates including triglycerides, phospholipids, cholesteryl esters, etc. The presence of bile salts is found to be very important for the activation of hCEase. Molecular dynamic simulations were performed for the apoform and bile salt complexed form of hCEase using the co-ordinates of two bile salts from bovine CEase. The stability of the systems throughout the simulation time was checked and two representative structures from the highly populated regions were selected using cluster analysis. These two representative structures were used in pharmacophore model generation. The generated pharmacophore models were validated and used in database screening. The screened hits were refined for their drug-like properties based on Lipinski's rule of five and ADMET properties. The drug-like compounds were further refined by molecular docking simulation using GOLD program based on the GOLD fitness score, mode of binding, and molecular interactions with the active site amino acids. Finally, three hits of novel scaffolds were selected as potential leads to be used in novel and potent hCEase inhibitor design. The stability of binding modes and molecular interactions of these final hits were re-assured by molecular dynamics simulations.

Mutations of the central tyrosines of putative cholesterol recognition amino acid consensus (CRAC) sequences modify folding, activity, and sterol-sensing of the human ABCG2 multidrug transporter.

PubMed

Gál, Zita; Hegedüs, Csilla; Szakács, Gergely; Váradi, András; Sarkadi, Balázs; Özvegy-Laczka, Csilla

2015-02-01

Human ABCG2 is a plasma membrane glycoprotein causing multidrug resistance in cancer. Membrane cholesterol and bile acids are efficient regulators of ABCG2 function, while the molecular nature of the sterol-sensing sites has not been elucidated. The cholesterol recognition amino acid consensus (CRAC, L/V-(X)(1-5)-Y-(X)(1-5)-R/K) sequence is one of the conserved motifs involved in cholesterol binding in several proteins. We have identified five potential CRAC motifs in the transmembrane domain of the human ABCG2 protein. In order to define their roles in sterol-sensing, the central tyrosines of these CRACs (Y413, 459, 469, 570 and 645) were mutated to S or F and the mutants were expressed both in insect and mammalian cells. We found that mutation in Y459 prevented protein expression; the Y469S and Y645S mutants lost their activity; while the Y570S, Y469F, and Y645F mutants retained function as well as cholesterol and bile acid sensitivity. We found that in the case of the Y413S mutant, drug transport was efficient, while modulation of the ATPase activity by cholesterol and bile acids was significantly altered. We suggest that the Y413 residue within a putative CRAC motif has a role in sterol-sensing and the ATPase/drug transport coupling in the ABCG2 multidrug transporter. Copyright © 2014. Published by Elsevier B.V.

The gut microbiota, bile acids and their correlation in primary sclerosing cholangitis associated with inflammatory bowel disease.

PubMed

Torres, J; Palmela, C; Brito, H; Bao, X; Ruiqi, H; Moura-Santos, P; Pereira da Silva, J; Oliveira, A; Vieira, C; Perez, K; Itzkowitz, S H; Colombel, J F; Humbert, L; Rainteau, D; Cravo, M; Rodrigues, C M; Hu, J

2018-02-01

Patients with primary sclerosing cholangitis associated with inflammatory bowel disease (PSC-IBD) have a very high risk of developing colorectal neoplasia. Alterations in the gut microbiota and/or gut bile acids could account for the increase in this risk. However, no studies have yet investigated the net result of cholestasis and a potentially altered bile acid pool interacting with a dysbiotic gut flora in the inflamed colon of PSC-IBD. The aim of this study was to compare the gut microbiota and stool bile acid profiles, as well as and their correlation in patients with PSC-IBD and inflammatory bowel disease alone. Thirty patients with extensive colitis (15 with concomitant primary sclerosing cholangitis) were prospectively recruited and fresh stool samples were collected. The microbiota composition in stool was profiled using bacterial 16S rRNA sequencing. Stool bile acids were assessed by high-performance liquid chromatography tandem mass spectrometry. The total stool bile acid pool was significantly reduced in PSC-IBD. Although no major differences were observed in the individual bile acid species in stool, their overall combination allowed a good separation between PSC-IBD and inflammatory bowel disease. Compared with inflammatory bowel disease alone, PSC-IBD patients demonstrated a different gut microbiota composition with enrichment in Ruminococcus and Fusobacterium genus compared with inflammatory bowel disease. At the operational taxonomic unit level major shifts were observed within the Firmicutes (73%) and Bacteroidetes phyla (17%). Specific microbiota-bile acid correlations were observed in PSC-IBD, where 12% of the operational taxonomic units strongly correlated with stool bile acids, compared with only 0.4% in non-PSC-IBD. Patients with PSC-IBD had distinct microbiota and microbiota-stool bile acid correlations as compared with inflammatory bowel disease. Whether these changes are associated with, or may predispose to, an increased risk of colorectal neoplasia needs to be further clarified.

In Vivo Performance of a Novel Fluorinated Magnetic Resonance Imaging Agent for Functional Analysis of Bile Acid Transport

PubMed Central

2015-01-01

A novel trifluorinated cholic acid derivative, CA-lys-TFA, was designed and synthesized for use as a tool to measure bile acid transport noninvasively using magnetic resonance imaging (MRI). In the present study, the in vivo performance of CA-lys-TFA for measuring bile acid transport by MRI was investigated in mice. Gallbladder CA-lys-TFA content was quantified using MRI and liquid chromatography/tandem mass spectrometry. Results in wild-type (WT) C57BL/6J mice were compared to those in mice lacking expression of Asbt, the ileal bile acid transporter. 19F signals emanating from the gallbladders of WT mice 7 h after oral gavage with 150 mg/kg CA-lys-TFA were reproducibly detected by MRI. Asbt-deficient mice administered the same dose had undetectable 19F signals by MRI, and gallbladder bile CA-lys-TFA levels were 30-fold lower compared to WT animals. To our knowledge, this represents the first report of in vivo imaging of an orally absorbed drug using 19F MRI. Fluorinated bile acid analogues have potential as tools to measure and detect abnormal bile acid transport by MRI. PMID:24708306

Defective canalicular transport and toxicity of dietary ursodeoxycholic acid in the abcb11-/- mouse: transport and gene expression studies.

PubMed

Wang, Renxue; Liu, Lin; Sheps, Jonathan A; Forrest, Dana; Hofmann, Alan F; Hagey, Lee R; Ling, Victor

2013-08-15

The bile salt export pump (BSEP), encoded by the abcb11 gene, is the major canalicular transporter of bile acids from the hepatocyte. BSEP malfunction in humans causes bile acid retention and progressive liver injury, ultimately leading to end-stage liver failure. The natural, hydrophilic, bile acid ursodeoxycholic acid (UDCA) is efficacious in the treatment of cholestatic conditions, such as primary biliary cirrhosis and cholestasis of pregnancy. The beneficial effects of UDCA include promoting bile flow, reducing hepatic inflammation, preventing apoptosis, and maintaining mitochondrial integrity in hepatocytes. However, the role of BSEP in mediating UDCA efficacy is not known. Here, we used abcb11 knockout mice (abcb11-/-) to test the effects of acute and chronic UDCA administration on biliary secretion, bile acid composition, liver histology, and liver gene expression. Acutely infused UDCA, or its taurine conjugate (TUDC), was taken up by the liver but retained, with negligible biliary output, in abcb11-/- mice. Feeding UDCA to abcb11-/- mice led to weight loss, retention of bile acids, elevated liver enzymes, and histological damage to the liver. Semiquantitative RT-PCR showed that genes encoding Mdr1a and Mdr1b (canalicular) as well as Mrp4 (basolateral) transporters were upregulated in abcb11-/- mice. We concluded that infusion of UDCA and TUDC failed to induce bile flow in abcb11-/- mice. UDCA fed to abcb11-/- mice caused liver damage and the appearance of biliary tetra- and penta-hydroxy bile acids. Supplementation with UDCA in the absence of Bsep caused adverse effects in abcb11-/- mice.

Molecular interactions between lecithin and bile salts/acids in oils and their effects on reverse micellization.

PubMed

Njauw, Ching-Wei; Cheng, Chih-Yang; Ivanov, Viktor A; Khokhlov, Alexei R; Tung, Shih-Huang

2013-03-26

It has been known that the addition of bile salts to lecithin organosols induces the formation of reverse wormlike micelles and that the worms are similar to long polymer chains that entangle each other to form viscoelastic solutions. In this study, we further investigated the effects of different bile salts and bile acids on the growth of lecithin reverse worms in cyclohexane and n-decane. We utilized rheological and small-angle scattering techniques to analyze the properties and structures of the reverse micelles. All of the bile salts can transform the originally spherical lecithin reverse micelles into wormlike micelles and their rheological behaviors can be described by the single-relaxation-time Maxwell model. However, their efficiencies to induce the worms are different. In contrast, before phase separation, bile acids can induce only short cylindrical micelles that are not long enough to impart viscoelasticity. We used Fourier transform infrared spectroscopy to investigate the interactions between lecithin and bile salts/acids and found that different bile salts/acids employ different functional groups to form hydrogen bonds with lecithin. Such effects determine the relative positions of the bile salts/acids in the headgroups of lecithin, thus resulting in varying efficiencies to alter the effective critical packing parameter for the formation of wormlike micelles. This work highlights the importance of intermolecular interactions in molecular self-assembly.

Physicochemical properties and biological activities of DEAE-derivatized Sphingomonas gellan.

PubMed

Yoo, Sang-Ho; Lee, Kyung Hee; Lee, Ji-Soo; Cha, Jaeho; Park, Cheon Seok; Lee, Hyeon Gyu

2005-08-10

Physicochemical characteristics and biological activities of Sphingomonas gellan (S-gellan) were investigated. The S-gellan weight fractions of Glc and GlcUA were 0.45 and 0.25, respectively, and the molar ratio of Glc:Rha:GlcUA was approximately 4:2:3. The S-gellan was chemically derivatized with diethylaminoethyl chloride-HCl (DEAE-HCl), and the resulting modified S-gellan contained both positive and negative charges. The elemental and IR analyses were conducted to confirm the successful incorporation of DEAE groups into S-gellan. A large increase in nitrogen fraction was observed from the derivatized S-gellan by elemental analysis. The IR absorption bands induced by C-H, C-N, and C-O-C stretching were noticeable at 2950, 1310-1380, and 1000-1150 cm(-1), respectively, resulting from the DEAE substitution. The characteristic CH3 and CH2 peaks originated from the DEAE group were detected in the 1H NMR spectrum of the derivatized S-gellan as well. The solubility of native S-gellan was improved almost twice from 40% to 75% after DEAE derivatization, while water holding capacity (WHC) drastically decreased from 10026% to 245%. Oil binding capacity (OBC) of S-gellan also significantly dropped from 1528% to 331% after the derivatization. The bile acid binding capacity of S-gellan was indirectly determined by measuring the holding capability of cholic acid inside the dialysis membrane (MWCO 12,000-14,000 Da). Once S-gellan was DEAE derivatized, there was substantial increase in the cholic acid retardation index (CRI). Up to 9 h of dialysis, the derivatized S-gellan released 29.3% less of cholic acid compared to the control group that did not contain S-gellan. From these results of the improved water solubility and stronger bile acid binding capacity, it would be suggested that the DEAE-derivatized S-gellan has more advantages than gellan itself for functional food applications.

Circadian dysregulation disrupts bile acid homeostasis

USDA-ARS?s Scientific Manuscript database

Bile acids are potentially toxic compounds and their levels of hepatic production, uptake, and export are tightly regulated by many inputs, including circadian rhythm. We tested the impact of disrupting the peripheral circadian clock on integral steps of bile acid homeostasis. Both restricted feedi...

The role of membrane cholesterol in determining bile acid cytotoxicity and cytoprotection of ursodeoxycholic acid

PubMed Central

Zhou, Yong; Doyen, Rand; Lichtenberger, Lenard M.

2013-01-01

In cholestatic liver diseases, the ability of hydrophobic bile acids to damage membranes of hepatocytes/ductal cells contributes to their cytotoxicity. However, ursodeoxycholic acid (UDC), a hydrophilic bile acid, is used to treat cholestasis because it protects membranes. It has been well established that bile acids associate with and solubilize free cholesterol (CHOL) contained within the lumen of the gallbladder because of their structural similarities. However, there is a lack of understanding of how membrane CHOL, which is a well-established membrane stabilizing agent, is involved in cytotoxicity of hydrophobic bile acids and the cytoprotective effect of UDC. We utilized phospholipid liposomes to examine the ability of membrane CHOL to influence toxicity of individual bile acids, such as UDC and the highly toxic sodium deoxycholate (SDC), as well as the cytoprotective mechanism of UDC against SDC-induced cytotoxicity by measuring membrane permeation and intramembrane dipole potential. The kinetics of bile acid solubilization of phosphatidylcholine liposomes containing various levels of CHOL was also characterized. It was found that the presence of CHOL in membranes significantly reduced the ability of bile acids to damage synthetic membranes. UDC effectively prevented damaging effects of SDC on synthetic membranes only in the presence of membrane CHOL, while UDC enhances the damaging effects of SDC in the absence of CHOL. This further demonstrates that the cytoprotective effects of UDC depend upon the level of CHOL in the lipid membrane. Thus, changes in cell membrane composition, such as CHOL content, potentially influence the efficacy of UDC as the primary drug used to treat cholestasis. PMID:19150330

The roles of bile acids and sphingosine-1-phosphate signaling in the hepatobiliary diseases

PubMed Central

Nagahashi, Masayuki; Yuza, Kizuki; Hirose, Yuki; Nakajima, Masato; Ramanathan, Rajesh; Hait, Nitai C.; Hylemon, Phillip B.; Zhou, Huiping; Takabe, Kazuaki; Wakai, Toshifumi

2016-01-01

Based on research carried out over the last decade, it has become increasingly evident that bile acids act not only as detergents, but also as important signaling molecules that exert various biological effects via activation of specific nuclear receptors and cell signaling pathways. Bile acids also regulate the expression of numerous genes encoding enzymes and proteins involved in the synthesis and metabolism of bile acids, glucose, fatty acids, and lipoproteins, as well as energy metabolism. Receptors activated by bile acids include, farnesoid X receptor α, pregnane X receptor, vitamin D receptor, and G protein-coupled receptors, TGR5, muscarinic receptor 2, and sphingosine-1-phosphate receptor (S1PR)2. The ligand of S1PR2, sphingosine-1-phosphate (S1P), is a bioactive lipid mediator that regulates various physiological and pathophysiological cellular processes. We have recently reported that conjugated bile acids, via S1PR2, activate and upregulate nuclear sphingosine kinase 2, increase nuclear S1P, and induce genes encoding enzymes and transporters involved in lipid and sterol metabolism in the liver. Here, we discuss the role of bile acids and S1P signaling in the regulation of hepatic lipid metabolism and in hepatobiliary diseases. PMID:27459945

Functional Intestinal Bile Acid 7α-Dehydroxylation by Clostridium scindens Associated with Protection from Clostridium difficile Infection in a Gnotobiotic Mouse Model.

PubMed

Studer, Nicolas; Desharnais, Lyne; Beutler, Markus; Brugiroux, Sandrine; Terrazos, Miguel A; Menin, Laure; Schürch, Christian M; McCoy, Kathy D; Kuehne, Sarah A; Minton, Nigel P; Stecher, Bärbel; Bernier-Latmani, Rizlan; Hapfelmeier, Siegfried

2016-01-01

Bile acids, important mediators of lipid absorption, also act as hormone-like regulators and as antimicrobial molecules. In all these functions their potency is modulated by a variety of chemical modifications catalyzed by bacteria of the healthy gut microbiota, generating a complex variety of secondary bile acids. Intestinal commensal organisms are well-adapted to normal concentrations of bile acids in the gut. In contrast, physiological concentrations of the various intestinal bile acid species play an important role in the resistance to intestinal colonization by pathogens such as Clostridium difficile . Antibiotic therapy can perturb the gut microbiota and thereby impair the production of protective secondary bile acids. The most important bile acid transformation is 7α-dehydroxylation, producing deoxycholic acid (DCA) and lithocholic acid (LCA). The enzymatic pathway carrying out 7α-dehydroxylation is restricted to a narrow phylogenetic group of commensal bacteria, the best-characterized of which is Clostridium scindens . Like many other intestinal commensal species, 7-dehydroxylating bacteria are understudied in vivo . Conventional animals contain variable and uncharacterized indigenous 7α-dehydroxylating organisms that cannot be selectively removed, making controlled colonization with a specific strain in the context of an undisturbed microbiota unfeasible. In the present study, we used a recently established, standardized gnotobiotic mouse model that is stably associated with a simplified murine 12-species "oligo-mouse microbiota" (Oligo-MM 12 ). It is representative of the major murine intestinal bacterial phyla, but is deficient for 7α-dehydroxylation. We find that the Oligo-MM 12 consortium carries out bile acid deconjugation, a prerequisite for 7α-dehydroxylation, and confers no resistance to C. difficile infection (CDI). Amendment of Oligo-MM 12 with C. scindens normalized the large intestinal bile acid composition by reconstituting 7α-dehydroxylation. These changes had only minor effects on the composition of the native Oligo-MM 12 , but significantly decreased early large intestinal C. difficile colonization and pathogenesis. The delayed pathogenesis of C. difficile in C. scindens -colonized mice was associated with breakdown of cecal microbial bile acid transformation.

The influence of bile acids on the oral bioavailability of vitamin K encapsulated in polymeric micelles.

PubMed

van Hasselt, P M; Janssens, G E P J; Slot, T K; van der Ham, M; Minderhoud, T C; Talelli, M; Akkermans, L M; Rijcken, C J F; van Nostrum, C F

2009-01-19

The purpose of this study was to assess the ability of polymeric micelles to enable gastrointestinal absorption of the extremely hydrophobic compound vitamin K, by comparison of its absorption in bile duct ligated and sham operated rats. Hereto, vitamin K was encapsulated in micelles composed of mPEG(5000)-b-p(HPMAm-lac(2)), a thermosensitive block copolymer. Vitamin K plasma levels rose significantly upon gastric administration of 1 mg vitamin K encapsulated in polymeric micelles in sham operated rats, but not after bile duct ligation (AUC 4543 and 1.64 ng/mL/h respectively, p<0.01). Duodenal administration of polymeric micelles together with bile acids in bile duct ligated rats fully restored absorption. Dynamic light scattering time series showed a significant and dose dependent rise in micellar size in the presence of bile acids in vitro, indicating the gradual formation of mixed micelles during the first 3 h of incubation. The highest bile acid amounts (11 mM deoxycholic acid and 41 mM taurocholic acid) eventually caused aggregation of the loaded micelles after the formation of mixed micelles. These data suggest that the gastrointestinal absorption of encapsulated vitamin K from polymeric micelles is mediated by free bile and that uptake of intact micelles through pinocytosis is insignificant.

Changes in the absorption of bile acids after total colectomy in patients with an ileostomy or pouch-anal anastomosis.

PubMed

Nasmyth, D G; Johnston, D; Williams, N S; King, R F; Burkinshaw, L; Brooks, K

1989-03-01

Bile acid absorption was investigated using 75Se Taurohomocholate (SeHCAT) in controls and patients who had undergone total colectomy with either conventional ileostomy or pouch-anal anastomosis for ulcerative colitis or adenomatous polyposis. Whole-body retention of SeHCAT after 168 hours was greater in the controls than the patients who had undergone colectomy (P less than .05). Retention of SeHCAT did not differ significantly between patients with an ileostomy and patients with pouch-anal anastomosis, but patients with an ileostomy and ileal resection of more than 20 cm retained less SeHCAT than patients with a pouch-anal anastomosis (P less than .01). Analysis of fecal bile acids from ileostomies and pouches showed that bacterial metabolism of primary conjugated bile acids was greater in patients with a pouch. It was concluded that bile acid absorption was not significantly impaired by construction of a pouch compared with conventional ileostomy, but bacterial metabolism of bile acids was greater in the pouches.

Hydrophilic bile acids protect human blood-brain barrier endothelial cells from disruption by unconjugated bilirubin: an in vitro study

PubMed Central

Palmela, Inês; Correia, Leonor; Silva, Rui F. M.; Sasaki, Hiroyuki; Kim, Kwang S.; Brites, Dora; Brito, Maria A.

2015-01-01

Ursodeoxycholic acid and its main conjugate glycoursodeoxycholic acid are bile acids with neuroprotective properties. Our previous studies demonstrated their anti-apoptotic, anti-inflammatory, and antioxidant properties in neural cells exposed to elevated levels of unconjugated bilirubin (UCB) as in severe jaundice. In a simplified model of the blood-brain barrier, formed by confluent monolayers of a cell line of human brain microvascular endothelial cells, UCB has shown to induce caspase-3 activation and cell death, as well as interleukin-6 release and a loss of blood-brain barrier integrity. Here, we tested the preventive and restorative effects of these bile acids regarding the disruption of blood-brain barrier properties by UCB in in vitro conditions mimicking severe neonatal hyperbilirubinemia and using the same experimental blood-brain barrier model. Both bile acids reduced the apoptotic cell death induced by UCB, but only glycoursodeoxycholic acid significantly counteracted caspase-3 activation. Bile acids also prevented the upregulation of interleukin-6 mRNA, whereas only ursodeoxycholic acid abrogated cytokine release. Regarding barrier integrity, only ursodeoxycholic acid abrogated UCB-induced barrier permeability. Better protective effects were obtained by bile acid pre-treatment, but a strong efficacy was still observed by their addition after UCB treatment. Finally, both bile acids showed ability to cross confluent monolayers of human brain microvascular endothelial cells in a time-dependent manner. Collectively, data disclose a therapeutic time-window for preventive and restorative effects of ursodeoxycholic acid and glycoursodeoxycholic acid against UCB-induced blood-brain barrier disruption and damage to human brain microvascular endothelial cells. PMID:25821432

Relationship between the effects of stress induced by human bile juice and acid treatment in Vibrio cholerae.

PubMed

Alvarez, Genoveva; Heredia, Norma; García, Santos

2003-12-01

The effects of low pH and human bile juice on Vibrio cholerae were investigated. A mild stress condition (exposure to acid shock at pH 5.5 or exposure to 3 mg of bile per ml for 20 min) slightly decreased (by < or = 1 log unit) V. cholerae cell viability. However, these treatments induced tolerance to subsequent exposures to more severe stress. In the O1 strain, four proteins were induced in response to acid shock (ca. 101, 94, 90, and 75 kDa), whereas only one protein (ca. 101 kDa) was induced in response to acid shock in the O139 strain. Eleven proteins were induced in response to bile shock in the O1 strain (ca. 106, 103, 101, 96, 88, 86, 84, 80, 66, 56, and 46 kDa), whereas only one protein was induced in response to bile shock in the O139 strain (ca. 88 kDa). V. cholerae O1 and O139 cells that had been preexposed to mild acid shock were twofold more resistant to pH 4.5 (with times required to inactivate 90% of the cell population [D-values] of 59 to 73 min) than were control cells (with D-values of 24 to 27 min). Likewise, cells that were preexposed to mild bile shock (3 mg/ml) were almost twofold more tolerant of severe bile shock (30 mg/ml; D-values, 68 to 87 min) than were control cells (with D-values of 37 to 43 min). These protective effects persisted for at least 1 h after the initial shock but were abolished when chloramphenicol was added to the culture during the shock. Cells preexposed to acid shock exhibited cross-protection against subsequent bile shock. However, cells preexposed to bile shock exhibited no changes in acid tolerance. Bile shock induced a modest reduction (0 to 20%) in enterotoxin production in V. cholerae, whereas acid shock had no effect on enterotoxin levels. Adaptation to acid and bile juice and protection against bile shock in response to preexposure to acid shock would be predicted to enhance the survival of V. cholerae in hosts and in foods. Thus, these adaptations may play an important role in the development of cholera disease.

[Structure determination of three novel bile acids from bear bile powder].

PubMed

Jian, Long-Hai; Mao, Xiu-Hong; Wang, Ke; Ji, Shen

2013-08-01

A method of LC-QTOF/MS combining with chemical synthesis has been used to determine the structures of three novel bile acids from bear bile powder. Reference substances of tauroursodeoxycholic acid and taurochenodeoxycholic acid were oxidized by pyridinium chlorochromate. The products were analyzed by LC-QTOF/MS. Total 4 products including 3 isomers were predicted and identified according to the PCC oxidation theory and LC-QTOF/MS results. Bear bile powder samples were dissolved by methanol and analyzed by LC-QTOF/MS. Three unknown peaks were found and identified as 2-[[(3beta, 5beta)-3-hydroxy-7, 24-dioxocholan-24-yl]amino]-ethanesulfonic acid, 2-[[(5beta)-3, 7, 24-trioxocholan-24-yl]amino]-ethanesulfonic acid and 2-[[(5beta, 7beta)-7-hydroxy-3, 24-dioxocholan-24-yl]amino]-ethanesulfonic acid, separately, by matching their results with that of oxidation products above.

Clinical Study of Ursodeoxycholic Acid in Barrett's Esophagus Patients.

PubMed

Banerjee, Bhaskar; Shaheen, Nicholas J; Martinez, Jessica A; Hsu, Chiu-Hsieh; Trowers, Eugene; Gibson, Blake A; Della'Zanna, Gary; Richmond, Ellen; Chow, H-H Sherry

2016-07-01

Prior research strongly implicates gastric acid and bile acids, two major components of the gastroesophageal refluxate, in the development of Barrett's esophagus and its pathogenesis. Ursodeoxycholic acid (UDCA), a hydrophilic bile acid, has been shown to protect esophageal cells against oxidative stress induced by cytotoxic bile acids. We conducted a pilot clinical study to evaluate the clinical activity of UDCA in patients with Barrett's esophagus. Twenty-nine patients with Barrett's esophagus received UDCA treatment at a daily dose of 13 to 15 mg/kg/day for 6 months. The clinical activity of UDCA was assessed by evaluating changes in gastric bile acid composition and markers of oxidative DNA damage (8-hydroxydeoxyguanosine), cell proliferation (Ki67), and apoptosis (cleaved caspase-3) in Barrett's esophagus epithelium. The bile acid concentrations in gastric fluid were measured by liquid chromatography/mass spectrometry. At baseline, UDCA (sum of unchanged and glycine/taurine conjugates) accounted for 18.2% of total gastric bile acids. After UDCA intervention, UDCA increased significantly to account for 93.4% of total gastric bile acids (P < 0.0001). The expression of markers of oxidative DNA damage, cell proliferation, and apoptosis was assessed in the Barrett's esophagus biopsies by IHC. The selected tissue biomarkers were unchanged after 6 months of UDCA intervention. We conclude that high-dose UDCA supplementation for 6 months resulted in favorable changes in gastric bile acid composition but did not modulate selected markers of oxidative DNA damage, cell proliferation, and apoptosis in the Barrett's esophagus epithelium. Cancer Prev Res; 9(7); 528-33. ©2016 AACRSee related article by Brian J. Reid, p. 512. ©2016 American Association for Cancer Research.

Effects of the bile acid UDCA on PDT efficacy in vitro and in vivo

NASA Astrophysics Data System (ADS)

Kessel, David; Castelli, Michelle; Sykes, Elizabeth; Garbo, Greta M.

2004-06-01

The phototoxicity of PDT in cell culture can be promoted by the relatively hydrophilic bile acid UDCA (ursodeoxycholic acid). This was attributed to a conformational change in the anti-apoptotic protein Bcl-2, leading to an enhanced sensitivity to photodamage by sensitizers that target sites of Bcl-2 localization. UDCA also promoted the binding and inactivation of Bcl-2 by the non-peptidic antagonist HA14- 1, suggesting that UDCA may also be useful for promoting chemotherapy designed to target Bcl-2. In tumor-bearing animals, addition of UDCA to a PDT protocol involving the tin etiopurpurin SnET2 resulted in enhanced cancer control, but there was no effect on the extent of PDT-induced vascular shut-down. These results are consistent with the propo proposal that UDCA only promotes direct tumor cell kill. In this report, we have sal summarized recent research relating to mode of action of UDCA as it effects the on the efficacy of photodynamic therapy where Bcl-2 is among the PDT targets, and discuss the implications of the results.

Functional and Probiotic Attributes of an Indigenous Isolate of Lactobacillus plantarum

PubMed Central

Kaushik, Jai K.; Kumar, Ashutosh; Duary, Raj K.; Mohanty, Ashok K.; Grover, Sunita; Batish, Virender K.

2009-01-01

Background Probiotic microorganisms favorably alter the intestinal microflora balance, promote intestinal integrity and mobility, inhibit the growth of harmful bacteria and increase resistance to infection. Probiotics are increasingly used in nutraceuticals, functional foods or in microbial interference treatment. However, the effectiveness of probiotic organism is considered to be population-specific due to variation in gut microflora, food habits and specific host-microbial interactions. Most of the probiotic strains available in the market are of western or European origin, and a strong need for exploring new indigenous probiotic organisms is felt. Methods and Findings An indigenous isolate Lp9 identified as Lactobacillus plantarum by molecular-typing methods was studied extensively for its functional and probiotic attributes, viz., acid and bile salt tolerance, cell surface hydrophobicity, autoaggregation and Caco-2 cell-binding as well as antibacterial and antioxidative activities. Lp9 isolate could survive 2 h incubation at pH 1.5–2.0 and toxicity of 1.5–2.0% oxgall bile. Lp9 could deconjugate major bile salts like glycocholate and deoxytaurocholate, indicating its potential to cause hypocholesterolemia. The isolate exhibited cell-surface hydrophobicity of ∼37% and autoaggregation of ∼31%. Presence of putative probiotic marker genes like mucus-binding protein (mub), fibronectin-binding protein (fbp) and bile salt hydrolase (bsh) were confirmed by PCR. Presence of these genes suggested the possibility of specific interaction and colonization potential of Lp9 isolate in the gut, which was also suggested by a good adhesion ratio of 7.4±1.3% with Caco-2 cell line. The isolate demonstrated higher free radical scavenging activity than standard probiotics L. johnsonii LA1 and L. acidophilus LA7. Lp9 also exhibited antibacterial activity against E. coli, L. monocytogenes, S. typhi, S. aureus and B. cereus. Conclusion The indigenous Lactobacillus plantarum Lp9 exhibited high resistance against low pH and bile and possessed antibacterial, antioxidative and cholesterol lowering properties with a potential for exploitation in the development of indigenous functional food or nutraceuticals. PMID:19956615

CYP2E1-dependent elevation of serum cholesterol, triglycerides, and hepatic bile acids by isoniazid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Jie; Krausz, Kristopher W.; Li, Feng

Isoniazid is the first-line medication in the prevention and treatment of tuberculosis. Isoniazid is known to have a biphasic effect on the inhibition–induction of CYP2E1 and is also considered to be involved in isoniazid-induced hepatotoxicity. However, the full extent and mechanism of involvement of CYP2E1 in isoniazid-induced hepatotoxicity remain to be thoroughly investigated. In the current study, isoniazid was administered to wild-type and Cyp2e1-null mice to investigate the potential toxicity of isoniazid in vivo. The results revealed that isoniazid caused no hepatotoxicity in wild-type and Cyp2e1-null mice, but produced elevated serum cholesterol and triglycerides, and hepatic bile acids in wild-typemore » mice, as well as decreased abundance of free fatty acids in wild-type mice and not in Cyp2e1-null mice. Metabolomic analysis demonstrated that production of isoniazid metabolites was elevated in wild-type mice along with a higher abundance of bile acids, bile acid metabolites, carnitine and carnitine derivatives; these were not observed in Cyp2e1-null mice. In addition, the enzymes responsible for bile acid synthesis were decreased and proteins involved in bile acid transport were significantly increased in wild-type mice. Lastly, treatment of targeted isoniazid metabolites to wild-type mice led to similar changes in cholesterol, triglycerides and free fatty acids. These findings suggest that while CYP2E1 is not involved in isoniazid-induced hepatotoxicity, while an isoniazid metabolite might play a role in isoniazid-induced cholestasis through enhancement of bile acid accumulation and mitochondria β-oxidation. -- Highlights: ► Isoniazid metabolites were elevated only in wild-type mice. ► Isoniazid caused no hepatotoxicity in wild-type and Cyp2e1-null mice. ► Isoniazid elevated serum cholesterol and triglycerides, and hepatic bile acids. ► Bile acid transporters were significantly decreased in isoniazid-treated mice.« less

Evolution of substrate specificity for the bile salt transporter ASBT (SLC10A2)[S

PubMed Central

Lionarons, Daniël A.; Boyer, James L.; Cai, Shi-Ying

2012-01-01

The apical Na+-dependent bile salt transporter (ASBT/SLC10A2) is essential for maintaining the enterohepatic circulation of bile salts. It is not known when Slc10a2 evolved as a bile salt transporter or how it adapted to substantial changes in bile salt structure during evolution. We characterized ASBT orthologs from two primitive vertebrates, the lamprey that utilizes early 5α-bile alcohols and the skate that utilizes structurally different 5β-bile alcohols, and compared substrate specificity with ASBT from humans who utilize modern 5β-bile acids. Everted gut sacs of skate but not the more primitive lamprey transported 3H-taurocholic acid (TCA), a modern 5β-bile acid. However, molecular cloning identified ASBT orthologs from both species. Cell-based assays using recombinant ASBT/Asbt's indicate that lamprey Asbt has high affinity for 5α-bile alcohols, low affinity for 5β-bile alcohols, and lacks affinity for TCA, whereas skate Asbt showed high affinity for 5α- and 5β-bile alcohols but low affinity for TCA. In contrast, human ASBT demonstrated high affinity for all three bile salt types. These findings suggest that ASBT evolved from the earliest vertebrates by gaining affinity for modern bile salts while retaining affinity for older bile salts. Also, our results indicate that the bile salt enterohepatic circulation is conserved throughout vertebrate evolution. PMID:22669917

Glucuronidation of 6 alpha-hydroxy bile acids by human liver microsomes.

PubMed Central

Radomińska-Pyrek, A; Zimniak, P; Irshaid, Y M; Lester, R; Tephly, T R; St Pyrek, J

1987-01-01

The glucuronidation of 6-hydroxylated bile acids by human liver microsomes has been studied in vitro; for comparison, several major bile acids lacking a 6-hydroxyl group were also investigated. Glucuronidation rates for 6 alpha-hydroxylated bile acids were 10-20 times higher than those of substrates lacking a hydroxyl group in position 6. The highest rates measured were for hyodeoxy- and hyocholic acids, and kinetic analyses were carried out using these substrates. Rigorous product identification by high-field proton nuclear magnetic resonance and by electron impact mass spectrometry of methyl ester/peracetate derivatives revealed that 6-O-beta-D-glucuronides were the exclusive products formed in these enzymatic reactions. These results, together with literature data, indicate that 6 alpha-hydroxylation followed by 6-O-glucuronidation constitutes an alternative route of excretion of toxic hydrophobic bile acids. PMID:3110212

Differential regulation of EGFR-MAPK signaling by deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) in colon cancer.

PubMed

Centuori, Sara M; Martinez, Jesse D

2014-10-01

A high-fat diet coincides with increased levels of bile acids. This increase in bile acids, particularly deoxycholic acid (DCA), has been strongly associated with the development of colon cancer. Conversely, ursodeoxycholic acid (UDCA) may have chemopreventive properties. Although structurally similar, DCA and UDCA present different biological and pathological effects in colon cancer progression. The differential regulation of cancer by these two bile acids is not yet fully understood. However, one possible explanation for their diverging effects is their ability to differentially regulate signaling pathways involved in the multistep progression of colon cancer, such as the epidermal growth factor receptor (EGFR)-mitogen-activated protein kinase (MAPK) pathway. This review will examine the biological effects of DCA and UDCA on colon cancer development, as well as the diverging effects of these bile acids on the oncogenic signaling pathways that play a role in colon cancer development, with a particular emphasis on bile acid regulation of the EGFR-MAPK pathway.

Differential regulation of EGFR-MAPK signaling by deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) in colon cancer

PubMed Central

Centuori, Sara M.; Martinez, Jesse D.

2014-01-01

A high fat diet coincides with elevated levels of bile acids. This elevation of bile acids, particularly deoxycholic acid (DCA), has been strongly associated with the development of colon cancer. Conversely, ursodeoxycholic acid (UDCA) may have chemopreventive properties. Although structurally similar, DCA and UDCA present different biological and pathological effects in colon cancer progression. The differential regulation of cancer by these two bile acids is not yet fully understood. However, one possible explanation for their diverging effects is their ability to differentially regulate signaling pathways involved in the multistep progression of colon cancer, such as the epidermal growth factor receptor (EGFR) mitogen-activated protein kinase (MAPK) pathway. This review will examine the biological effects of DCA and UDCA on colon cancer development, as well as the diverging effects of these bile acids on the oncogenic signaling pathways that play a role in colon cancer development, with a particular emphasis on bile acid regulation of the EGFR-MAPK pathway. PMID:25027205

Characterization of Rose Bengal binding to sinusoidal and bile canalicular plasma membrane from rat liver.

PubMed

Yachi, K; Sugiyama, Y; Sawada, Y; Iga, T; Ikeda, Y; Toda, G; Hanano, M

1989-01-16

The binding of Rose bengal, a model organic anion, to sinusoidal and bile canalicular membrane fractions isolated from rat liver was compared. The fluorescence change of Rose bengal after being bound to liver plasma membranes was utilized for measuring the binding. The dissociation constants (Kd = 0.1-0.12 microM) and the binding capacities (n = 11-15 nmol/mg protein) for Rose bengal are comparable between the two membrane fractions, although the n value for sinusoidal membrane is somewhat larger than that for bile canalicular membrane. The Rose bengal binding to both membrane fractions was inhibited by various organic anions at relatively low concentrations, i.e., the half-inhibition concentrations (IC50) for Indocyanine green, sulfobromophthalein, Bromophenol blue and 1-anilino-8-naphthalene sulfonate were 0.1, 100, 1.5-2.5 and 100 microM, respectively, while taurocholate did not inhibit the Rose bengal binding to either membrane fraction at these low concentration ranges. The type of inhibition of sulfobromophthalein and Indocyanine green for Rose bengal binding is different between the two membrane domains. That is, in sinusoidal and bile canalicular membrane fractions, these organic anions exhibit mixed-type and competitive-type inhibition, respectively. It was suggested that the fluorescence method using Rose bengal may provide a simple method for detecting the specific organic anion binding protein(s) in the liver plasma membrane.

Whey protein isolate improves acid and bile tolerances of Streptococcus thermophilus ST-M5 and Lactobacillus delbrueckii ssp. bulgaricus LB-12.

PubMed

Vargas, Luis A; Olson, Douglas W; Aryana, Kayanush J

2015-04-01

Acid tolerance and bile tolerance are important probiotic characteristics. Whey proteins contain branched-chain amino acids, which play a role in muscle building and are popular among athletes. Increasing emphasis is being placed on diets containing less carbohydrate, less fat, and more protein. The effect of incremental additions of whey protein isolate (WPI) on probiotic characteristics of pure cultures is not known. The objective of this study was to determine the influence of added WPI on acid tolerance and bile tolerance of pure cultures of Streptococcus thermophilus ST-M5 and Lactobacillus bulgaricus LB-12. The WPI was used at 0 (control), 1, 2 and 3% (wt/vol). Assessment of acid tolerance was conducted on pure cultures at 30-min intervals for 2h of acid exposure and bile tolerance at 1-h intervals for 5h of bile exposure. Use of 1, 2, and 3% WPI improved acid tolerance of Strep. thermophilus ST-M5 and Lb. bulgaricus LB-12. The highest counts for acid tolerance of Strep. thermophilus ST-M5 and Lb. bulgaricus LB-12 were obtained when 3% WPI was used. Use of 2 and 3% WPI improved bile tolerance of Strep. thermophilus ST-M5 and Lb. bulgaricus LB-12 over 5h of bile exposure. The use of WPI is recommended to improve acid and bile tolerance of the yogurt culture bacteria Strep. thermophilus ST-M5 and Lb. bulgaricus LB-12. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Bile Acids Improve the Antimicrobial Effect of Rifaximin▿ †

PubMed Central

Darkoh, Charles; Lichtenberger, Lenard M.; Ajami, Nadim; Dial, Elizabeth J.; Jiang, Zhi-Dong; DuPont, Herbert L.

2010-01-01

Diarrhea is one of the most common infirmities affecting international travelers, occurring in 20 to 50% of persons from industrialized countries visiting developing regions. Enterotoxigenic Escherichia coli (ETEC) is the most common causative agent and is isolated from approximately half of the cases of traveler's diarrhea. Rifaximin, a largely water-insoluble, nonabsorbable (<0.4%) antibiotic that inhibits bacterial RNA synthesis, is approved for use for the treatment of traveler's diarrhea caused by diarrheagenic E. coli. However, the drug has minimal effect on the bacterial flora or the infecting E. coli strain in the aqueous environment of the colon. The purpose of the present study was to evaluate the antimicrobial effect and bioavailability of rifaximin in aqueous solution in the presence and absence of physiologic concentrations of bile acids. The methods used included growth measurement of ETEC (strain H10407), rifaximin solubility measurements, total bacterial protein determination, and assessment of the functional activity of rifaximin by monitoring inhibition of bacterial β-galactosidase expression. Solubility studies showed rifaximin to be 70- to 120-fold more soluble in bile acids (approximately 30% in 4 mM bile acids) than in aqueous solution. Addition of both purified bile acids and human bile to rifaximin at subinhibitory and inhibitory concentrations significantly improved the drug's anti-ETEC effect by 71% and 73%, respectively, after 4 h. This observation was confirmed by showing a decrease in the overall amount of total bacterial protein expressed during incubation of rifaximin plus bile acids. Rifaximin-treated samples containing bile acids inhibited the expression of ETEC β-galactosidase at a higher magnitude than samples that did not contain bile acids. The study provides data showing that bile acids solubilize rifaximin on a dose-response basis, increasing the drug's bioavailability and antimicrobial effect. These observations suggest that rifaximin may be more effective in the treatment of infections in the small intestine, due to the higher concentration of bile in this region of the gastrointestinal tract than in the colon. The water insolubility of rifaximin is the likely explanation for the drug's minimal effects on colonic flora and fecal pathogens, despite in vitro susceptibility. PMID:20547807

[Simultaneous determination of eight kinds of conjunct bile acids in human bile by R-HPLC].

PubMed

Dai, Z; Tan, G; Qian, K; Chen, X

1997-01-01

A method for the simultaneous determination of eight kinds of conjunct bile acids in human bile was developed by HPLC. They were separated on a YWG-C18 (3 microns) column at 30 degrees C, with methanol/water (65/35, V/V, pH3.0) as mobile phase, and detection wavelength at UV 210 nm. The linear ranges were 50-1,000 microns.ml-1, the recoveries were 91.2%-108.6%. The biles of 30 cases with cholelithiasis cholecystolithiasis and 20 cases without gallstone were detected by HPLC. The results showed that the constitution of bile acids was different between patients with cholelithiasis cholecystolithiasis and patients without gallstone.

Acid and bile tolerance of spore-forming lactic acid bacteria.

PubMed

Hyronimus, B; Le Marrec, C; Sassi, A H; Deschamps, A

2000-11-01

Criteria for screening probiotics such as bile tolerance and resistance to acids were studied with 13 spore-forming lactic acid producing bacteria. Different strains of Sporolactobacillus, Bacillus laevolacticus, Bacillus racemilacticus and Bacillus coagulans grown in MRS broth were subjected to low pH conditions (2, 2.5 and 3) and increasing bile concentrations. Among these microorganisms, Bacillus laevolacticus DSM 6475 and all Sporolactobacillus strains tested except Sporolactobacillus racemicus IAM 12395, were resistant to pH 3. Only Bacillus racemilacticus and Bacillus coagulans strains were tolerant to bile concentrations over 0.3% (w/v).

Effects of Bile Acids and Nisin on the Production of Enterotoxin by Clostridium perfringens in a Nutrient-Rich Medium.

PubMed

Park, Miseon; Rafii, Fatemeh

2018-01-01

Clostridium perfringens is the second most common cause of bacterial foodborne illness in the United States, with nearly a million cases each year. C. perfringens enterotoxin (CPE), produced during sporulation, damages intestinal epithelial cells by pore formation, which results in watery diarrhea. The effects of low concentrations of nisin and bile acids on sporulation and toxin production were investigated in C. perfringens SM101, which carries an enterotoxin gene on the chromosome, in a nutrient-rich medium. Bile acids and nisin increased production of enterotoxin in cultures; bile acids had the highest effect. Both compounds stimulated the transcription of enterotoxin and sporulation-related genes and production of spores during the early growth phase. They also delayed spore outgrowth and nisin was more inhibitory. Bile acids and nisin enhanced enterotoxin production in some but not all other C. perfringens isolates tested. Low concentrations of bile acids and nisin may act as a stress signal for the initiation of sporulation and the early transcription of sporulation-related genes in some strains of C. perfringens , which may result in increased strain-specific production of enterotoxin in those strains. This is the first report showing that nisin and bile acids stimulated the transcription of enterotoxin and sporulation-related genes in a nutrient-rich bacterial culture medium.

Relation between reflux of bile acids into the stomach and gastric mucosal atrophy, intestinal metaplasia in biopsy specimens.

PubMed

Matsuhisa, Takeshi; Tsukui, Taku

2012-05-01

During endoscopic examinations we collected fluid in the stomach that included reflux fluid from the duodenum, and assessed the effect of quantitatively determined bile acids on glandular atrophy and intestinal metaplasia using biopsy specimens. A total of 294 outpatients were enrolled in this study. Total bile acid concentration was measured by an enzyme immunoassay. Glandular atrophy and intestinal metaplasia scores were graded according to the Updated Sydney System. An effect of refluxed bile acids on atrophy and intestinal metaplasia was shown in the high-concentration reflux group in comparison with the control group. However, when the odds ratios (ORs) were calculated according to whether Helicobacter pylori (H. pylori) infection was present, no significant associations were shown between reflux bile acids and atrophy in either the H. pylori-positive cases or -negative cases. The same was true for intestinal metaplasia in the H. pylori-positive cases, whereas intestinal metaplasia was more pronounced in the high-concentration reflux group in the H. pylori-negative cases (OR 2.4, 95%CI 1.1-5.6). We could not clarify the effect of the reflux of bile acids into the stomach in the progression of atrophy. High-concentration bile acids had an effect on the progression of intestinal metaplasia in the H. pylori-negative cases.

The Role of Bile After Roux-en-Y Gastric Bypass in Promoting Weight Loss and Improving Glycaemic Control

PubMed Central

Pournaras, Dimitri J.; Glicksman, Clare; Vincent, Royce P.; Kuganolipava, Shophia; Alaghband-Zadeh, Jamie; Mahon, David; Bekker, Jan H.R.; Ghatei, Mohammad A.; Bloom, Stephen R.; Walters, Julian R.F.; le Roux, Carel W.

2012-01-01

Gastric bypass leads to the remission of type 2 diabetes independently of weight loss. Our hypothesis is that changes in bile flow due to the altered anatomy may partly explain the metabolic outcomes of the operation. We prospectively studied 12 patients undergoing gastric bypass and six patients undergoing gastric banding over a 6-wk period. Plasma fibroblast growth factor (FGF)19, stimulated by bile acid absorption in the terminal ileum, and plasma bile acids were measured. In canine and rodent models, we investigated changes in the gut hormone response after altered bile flow. FGF19 and total plasma bile acids levels increased after gastric bypass compared with no change after gastric banding. In the canine model, both food and bile, on their own, stimulated satiety gut hormone responses. However, when combined, the response was doubled. In rats, drainage of endogenous bile into the terminal ileum was associated with an enhanced satiety gut hormone response, reduced food intake, and lower body weight. In conclusion, after gastric bypass, bile flow is altered, leading to increased plasma bile acids, FGF19, incretin. and satiety gut hormone concentrations. Elucidating the mechanism of action of gastric bypass surgery may lead to novel treatments for type 2 diabetes. PMID:22673227

Complementary stimulation of hepatobiliary transport and detoxification systems by rifampicin and ursodeoxycholic acid in humans.

PubMed

Marschall, Hanns-Ulrich; Wagner, Martin; Zollner, Gernot; Fickert, Peter; Diczfalusy, Ulf; Gumhold, Judith; Silbert, Dagmar; Fuchsbichler, Andrea; Benthin, Lisbet; Grundström, Rosita; Gustafsson, Ulf; Sahlin, Staffan; Einarsson, Curt; Trauner, Michael

2005-08-01

Rifampicin (RIFA) and ursodeoxycholic acid (UDCA) improve symptoms and biochemical markers of liver injury in cholestatic liver diseases by largely unknown mechanisms. We aimed to study the molecular mechanisms of action of these drugs in humans. Thirty otherwise healthy gallstone patients scheduled for cholestectomy were randomized to RIFA (600 mg/day for 1 week) or UDCA (1 g/day for 3 weeks) or no medication before surgery. Routine biochemistry, lipids, and surrogate markers for P450 activity (4beta-hydroxy cholesterol, 4beta-OH-C) and bile acid synthesis (7alpha-hydroxy-4-cholesten-3-one, C-4) were measured in serum. Bile acids were analyzed in serum, urine, and bile. A wedge liver biopsy specimen was taken to study expression of hepatobiliary ABC transporters as well as detoxification enzymes and regulatory transcription factors. RIFA enhanced bile acid detoxification as well as bilirubin conjugation and excretion as reflected by enhanced expression of CYP3A4, UGT1A1, and MRP2. These molecular effects were paralleled by decreased bilirubin and deoxycholic acid concentrations in serum and decreased lithocholic and deoxycholic acid concentrations in bile. UDCA on the other hand stimulated the expression of BSEP, MDR3, and MRP4. UDCA became the predominant bile acid after UDCA treatment and lowered the biliary cholesterol saturation index. RIFA enhances bile acid detoxification as well as bilirubin conjugation and export systems, whereas UDCA stimulates the expression of transporters for canalicular and basolateral bile acid export as well as the canalicular phospholipid flippase. These independent but complementary effects may justify a combination of both agents for the treatment of cholestatic liver diseases.

Bile Stress Response in Listeria monocytogenes LO28: Adaptation, Cross-Protection, and Identification of Genetic Loci Involved in Bile Resistance

PubMed Central

Begley, Máire; Gahan, Cormac G. M.; Hill, Colin

2002-01-01

Bile is one of many barriers that Listeria monocytogenes must overcome in the human gastrointestinal tract in order to infect and cause disease. We demonstrated that stationary-phase cultures of L. monocytogenes LO28 were able to tolerate concentrations of bovine, porcine, and human bile and bile acids well in excess of those encountered in vivo. Strain LO28 was relatively bile resistant compared with other clinical isolates of L. monocytogenes, as well as with Listeria innocua, Salmonella enterica serovar Typhimurium LT2, and Lactobacillus sakei. While exponential-phase L. monocytogenes LO28 cells were exquisitely sensitive to unconjugated bile acids, prior adaptation to sublethal levels of bile acids or heterologous stresses, such as acid, heat, salt, or sodium dodecyl sulfate (SDS), significantly enhanced bile resistance. This adaptive response was independent of protein synthesis, and in the cases of bile and SDS adaptation, occurred in seconds. In order to identify genetic loci involved in the bile tolerance phenotype of L. monocytogenes LO28, transposon (Tn917) and plasmid (pORI19) integration banks were screened for bile-sensitive mutants. The disrupted genes included a homologue of the capA locus required for capsule formation in Bacillus anthracis; a gene encoding the transcriptional regulator ZurR; a homologue of an Escherichia coli gene, lytB, involved in isoprenoid biosynthesis; a gene encoding a homologue of the Bacillus subtilis membrane protein YxiO; and a gene encoding an amino acid transporter with a putative role in pH homeostasis, gadE. Interestingly, all of the identified loci play putative roles in maintenance of the cell envelope or in stress responses. PMID:12450822

Synthesis, physicochemical properties, and biological activity of bile acids 3-glucuronides: Novel insights into bile acid signalling and detoxification.

PubMed

Mostarda, Serena; Passeri, Daniela; Carotti, Andrea; Cerra, Bruno; Colliva, Carolina; Benicchi, Tiziana; Macchiarulo, Antonio; Pellicciari, Roberto; Gioiello, Antimo

2018-01-20

Glucuronidation is considered an important detoxification pathway of bile acids especially in cholestatic conditions. Glucuronides are less toxic than the parent free forms and are more easily excreted in urine. However, the pathophysiological significance of bile acid glucuronidation is still controversial and debated among the scientific community. Progress in this field has been strongly limited by the lack of appropriate methods for the preparation of pure glucuronides in the amount needed for biological and pharmacological studies. In this work, we have developed a new synthesis of bile acid C3-glucuronides enabling the convenient preparation of gram-scale quantities. The synthesized compounds have been characterized in terms of physicochemical properties and abilities to modulate key nuclear receptors including the farnesoid X receptor (FXR). In particular, we found that C3-glucuronides of chenodeoxycholic acid and lithocholic acid, respectively the most abundant and potentially cytotoxic species formed in patients affected by cholestasis, behave as FXR agonists and positively regulate the gene expression of transporter proteins, the function of which is critical in human conditions related to imbalances of bile acid homeostasis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Direct methylation of FXR by Set7/9, a lysine methyltransferase, regulates the expression of FXR target genes

PubMed Central

Balasubramaniyan, Natarajan; Ananthanarayanan, Meena

2012-01-01

The farnesoid X receptor (FXR) is a ligand (bile acid)-dependent nuclear receptor that regulates target genes involved in every aspect of bile acid homeostasis. Upon binding of ligand, FXR recruits an array of coactivators and associated proteins, some of which have intrinsic enzymatic activity that modify histones or even components of the transcriptional complex. In this study, we show chromatin occupancy by the Set7/9 methyltransferase at the FXR response element (FXRE) and direct methylation of FXR in vivo and in vitro at lysine 206. siRNA depletion of Set7/9 in the Huh-7 liver cell line decreased endogenous mRNAs of the FXR target genes, the short heterodimer partner (SHP) and bile salt export pump (BSEP). Mutation of the methylation site at K206 of FXR to an arginine prevented methylation by Set7/9. A pan-methyllysine antibody recognized the wild-type FXR but not the K206R mutant form. An electromobility shift assay showed that methylation by Set7/9 enhanced binding of FXR/retinoic X receptor-α to the FXRE. Interaction between hinge domain of FXR (containing K206) and Set7/9 was confirmed by coimmunoprecipitation, GST pull down, and mammalian two-hybrid experiments. Set7/9 overexpression in Huh-7 cells significantly enhanced transactivation of the SHP and BSEP promoters in a ligand-dependent fashion by wild-type FXR but not the K206R mutant FXR. A Set7/9 mutant deficient in methyltransferase activity was also not effective in increasing transactivation of the BSEP promoter. These studies demonstrate that posttranslational methylation of FXR by Set7/9 contributes to the transcriptional activation of FXR-target genes. PMID:22345554

Homologue gene of bile acid transporters ntcp, asbt, and ost-alpha in rainbow trout Oncorhynchus mykiss: tissue expression, effect of fasting, and response to bile acid administration.

PubMed

Murashita, Koji; Yoshiura, Yasutoshi; Chisada, Shin-Ichi; Furuita, Hirofumi; Sugita, Tsuyoshi; Matsunari, Hiroyuki; Iwashita, Yasuro; Yamamoto, Takeshi

2014-04-01

Bile acid transporters belonging to the SLC10A protein family, Na+ taurocholate cotransporting polypeptide (NTCP or SLC10A1), apical sodium-dependent bile salt transporter (ASBT or SLC10A2), and organic solute transporter alpha (Ost-alpha) have been known to play critical roles in the enterohepatic circulation of bile acids in mammals. In this study, ntcp, asbt, and ost-alpha-1/-2 cDNA were cloned, their tissue distributions were characterized, and the effects of fasting and bile acid administration on their expression were examined in rainbow trout Oncorhynchus mykiss. The structural characteristics of Ntcp, Asbt, and Ost-alpha were well conserved in trout, and three-dimensional structure analysis showed that Ntcp and Asbt were similar to each other. Tissue distribution analysis revealed that trout asbt was primarily expressed in the hindgut, while ntcp expression occurred in the brain, and ost-alpha-1/-2 was mainly expressed in the liver or ovary. Although asbt and ost-alpha-1 mRNA levels in the gut increased in response to fasting for 4 days, ost-alpha-1 expression in the liver decreased. Similarly, bile acid administration increased asbt and ost-alpha-1 expression levels in the gut, while those of ntcp and ost-alpha-2 in the liver decreased. These results suggested that the genes asbt, ntcp, and ost-alpha are involved in bile acid transport in rainbow trout.

Potential mechanism of corpus-predominant gastritis after PPI therapy in Helicobacter pylori-positive patients with GERD.

PubMed

Mukaisho, Ken-ichi; Hagiwara, Tadashi; Nakayama, Takahisa; Hattori, Takanori; Sugihara, Hiroyuki

2014-09-14

The long-term use of proton pump inhibitors (PPIs) exacerbates corpus atrophic gastritis in patients with Helicobacter pylori (H. pylori) infection. To identify a potential mechanism for this change, we discuss interactions between pH, bile acids, and H. pylori. Duodenogastric reflux, which includes bile, occurs in healthy individuals, and bile reflux is increased in patients with gastroesophageal reflux disease (GERD). Diluted human plasma and bile acids have been found to be significant chemoattractants and chemorepellents, respectively, for the bacillus H. pylori. Although only taurine conjugates, with a pKa of 1.8-1.9, are soluble in an acidic environment, glycine conjugates, with a pKa of 4.3-5.2, as well as taurine-conjugated bile acids are soluble in the presence of PPI therapy. Thus, the soluble bile acid concentrations in the gastric contents of patients with GERD after continuous PPI therapy are considerably higher than that in those with intact acid production. In the distal stomach, the high concentration of soluble bile acids is likely to act as a bactericide or chemorepellent for H. pylori. In contrast, the mucous layer in the proximal stomach has an optimal bile concentration that forms chemotactic gradients with plasma components required to direct H. pylori to the epithelial surface. H. pylori may then colonize in the stomach body rather than in the pyloric antrum, which may explain the occurrence of corpus-predominant gastritis after PPI therapy in H. pylori-positive patients with GERD.

Perturbation of bile acid homeostasis is an early pathogenesis event of drug induced liver injury in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamazaki, Makoto; Miyake, Manami; Sato, Hiroko

2013-04-01

Drug-induced liver injury (DILI) is a significant consideration for drug development. Current preclinical DILI assessment relying on histopathology and clinical chemistry has limitations in sensitivity and discordance with human. To gain insights on DILI pathogenesis and identify potential biomarkers for improved DILI detection, we performed untargeted metabolomic analyses on rats treated with thirteen known hepatotoxins causing various types of DILI: necrosis (acetaminophen, bendazac, cyclosporine A, carbon tetrachloride, ethionine), cholestasis (methapyrilene and naphthylisothiocyanate), steatosis (tetracycline and ticlopidine), and idiosyncratic (carbamazepine, chlorzoxasone, flutamide, and nimesulide) at two doses and two time points. Statistical analysis and pathway mapping of the nearly 1900 metabolitesmore » profiled in the plasma, urine, and liver revealed diverse time and dose dependent metabolic cascades leading to DILI by the hepatotoxins. The most consistent change induced by the hepatotoxins, detectable even at the early time point/low dose, was the significant elevations of a panel of bile acids in the plasma and urine, suggesting that DILI impaired hepatic bile acid uptake from the circulation. Furthermore, bile acid amidation in the hepatocytes was altered depending on the severity of the hepatotoxin-induced oxidative stress. The alteration of the bile acids was most evident by the necrosis and cholestasis hepatotoxins, with more subtle effects by the steatosis and idiosyncratic hepatotoxins. Taking together, our data suggest that the perturbation of bile acid homeostasis is an early event of DILI. Upon further validation, selected bile acids in the circulation could be potentially used as sensitive and early DILI preclinical biomarkers. - Highlights: ► We used metabolomics to gain insights on drug induced liver injury (DILI) in rats. ► We profiled rats treated with thirteen hepatotoxins at two doses and two time points. ► The toxins decreased the liver's ability to uptake bile acid from the circulation. ► Oxidative stress induced by the toxins altered bile acid biosynthesis in the liver. ► Selected bile acids in the plasma and urine could be sensitive DILI biomarkers.« less

Promising toxicological biomarkers for the diagnosis of liver injury types: Bile acid metabolic profiles and oxidative stress marker as screening tools in drug development.

PubMed

Masubuchi, Noriko; Nishiya, Takayoshi; Imaoka, Masako; Mizumaki, Kiyoko; Okazaki, Osamu

2016-08-05

Promising biomarkers were identified in adult male Crl:CD (SD) rats for the screening of new chemical entities for their potential to cause liver injury. We examined the serum biochemistry, liver histopathology, and bile acid profiles by LC-MS/MS, and the mRNA expression of transporters and CYPs by an RT-PCR after the following treatments to male Crl:CD (SD) rats: (a) bile duct ligation (BDL); (b) a single oral dose of 150 mg/kg α-naphthylisothiocyanate (ANIT); and (c) repeated oral doses of a novel pyrrolidinecarboxylic acid derivative (abbreviated as PCA) at 30, 300, and 1000 mg/kg. The serum total bile acid levels and bilirubin concentrations were found to be elevated in all of the groups. However, the bile acid component profiles of the PCA group differed significantly from BDL and ANIT models: deoxycholic acid, lithocholic acid, and sulfated bile acids were upregulated in a dose-dependent manner only in the PCA group. In addition, the PCA group demonstrated high levels of hepatic heme oxygenase-1 expression, whereas the profiles of the mRNA levels of the hepatic transporters and CYPs of all groups were found to be similar. The histopathological findings, for both the BDL and ANIT groups, were of bile duct hyperplasia, hepatocyte degeneration and necrosis. In contrast, only bile duct hyperplasia and hepatocyte degeneration were observed in the PCA group, even at a lethal dose. These results indicated that PCA induced a cholestatic condition and the increase of oxidative stress markers implies that this will also lead hepatocellular injury. In conclusion, the serum bile acid components and sulfated bile acid levels, and the expression of oxidative stress markers could provide information that aids in the diagnosis of liver injury type and helps to elucidate the mechanisms of hepatotoxicity. These findings can be extrapolated into our clinical investigation. The analysis of these crucial biomarkers is likely to be a useful screening tool in the lead optimization phase of drug discovery. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Recombinant proteins incorporating short non-native extensions may display increased aggregation propensity as detected by high resolution NMR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zanzoni, Serena; D'Onofrio, Mariapina; Molinari, Henriette

2012-10-26

Highlights: Black-Right-Pointing-Pointer Bile acid binding proteins from different constructs retain structural integrity. Black-Right-Pointing-Pointer NMR {sup 15}N-T{sub 1} relaxation data of BABPs show differences if LVPR extension is present. Black-Right-Pointing-Pointer Deviations from a {sup 15}N-T{sub 1}/molecular-weight calibration curve indicate aggregation. -- Abstract: The use of a recombinant protein to investigate the function of the native molecule requires that the former be obtained with the same amino acid sequence as the template. However, in many cases few additional residues are artificially introduced for cloning or purification purposes, possibly resulting in altered physico-chemical properties that may escape routine characterization. For example, increased aggregationmore » propensity without visible protein precipitation is hardly detected by most analytical techniques but its investigation may be of great importance for optimizing the yield of recombinant protein production in biotechnological and structural biology applications. In this work we show that bile acid binding proteins incorporating the common C-terminal LeuValProArg extension display different hydrodynamic properties from those of the corresponding molecules without such additional amino acids. The proteins were produced enriched in nitrogen-15 for analysis via heteronuclear NMR spectroscopy. Residue-specific spin relaxation rates were measured and related to rotational tumbling time and molecular size. While the native-like recombinant proteins show spin-relaxation rates in agreement with those expected for monomeric globular proteins of their mass, our data indicate the presence of larger adducts for samples of proteins with very short amino acid extensions. The used approach is proposed as a further screening method for the quality assessment of biotechnological protein products.« less

Overexpression of the cholesterol-binding protein MLN64 induces liver damage in the mouse

PubMed Central

Tichauer, Juan Enrique; Morales, María Gabriela; Amigo, Ludwig; Galdames, Leopoldo; Klein, Andrés; Quiñones, Verónica; Ferrada, Carla; R, Alejandra Alvarez; Rio, Marie-Christine; Miquel, Juan Francisco; Rigotti, Attilio; Zanlungo, Silvana

2007-01-01

AIM: To examine the in vivo phenotype associated with hepatic metastatic lymph node 64 (MLN64) over-expression. METHODS: Recombinant-adenovirus-mediated MLN64 gene transfer was used to overexpress MLN64 in the livers of C57BL/6 mice. We measured the effects of MLN64 overexpression on hepatic cholesterol content, bile flow, biliary lipid secretion and apoptosis markers. For in vitro studies cultured CHO cells with transient MLN64 overexpression were utilized and apoptosis by TUNEL assay was measured. RESULTS: Livers from Ad.MLN64-infected mice exhibited early onset of liver damage and apoptosis. This response correlated with increases in liver cholesterol content and biliary bile acid concentration, and impaired bile flow. We investigated whether liver MLN64 expression could be modulated in a murine model of hepatic injury. We found increased hepatic MLN64 mRNA and protein levels in mice with chenodeoxycholic acid-induced liver damage. In addition, cultured CHO cells with transient MLN64 overexpression showed increased apoptosis. CONCLUSION: In summary, hepatic MLN64 over-expression induced damage and apoptosis in murine livers and altered cholesterol metabolism. Further studies are required to elucidate the relevance of these findings under physiologic and disease conditions. PMID:17589922

Cyclosporin derivatives inhibit hepatitis B virus entry without interfering with NTCP transporter activity.

PubMed

Shimura, Satomi; Watashi, Koichi; Fukano, Kento; Peel, Michael; Sluder, Ann; Kawai, Fumihiro; Iwamoto, Masashi; Tsukuda, Senko; Takeuchi, Junko S; Miyake, Takeshi; Sugiyama, Masaya; Ogasawara, Yuki; Park, Sam-Yong; Tanaka, Yasuhito; Kusuhara, Hiroyuki; Mizokami, Masashi; Sureau, Camille; Wakita, Takaji

2017-04-01

The sodium taurocholate co-transporting polypeptide (NTCP) is the main target of most hepatitis B virus (HBV) specific entry inhibitors. Unfortunately, these agents also block NTCP transport of bile acids into hepatocytes, and thus have the potential to cause adverse effects. We aimed to identify small molecules that inhibit HBV entry while maintaining NTCP transporter function. We characterized a series of cyclosporine (CsA) derivatives for their anti-HBV activity and NTCP binding specificity using HepG2 cells overexpressing NTCP and primary human hepatocytes. The four most potent derivatives were tested for their capacity to prevent HBV entry, but maintain NTCP transporter function. Their antiviral activity against different HBV genotypes was analysed. We identified several CsA derivatives that inhibited HBV infection with a sub-micromolar IC 50 . Among them, SCY446 and SCY450 showed low activity against calcineurin (CN) and cyclophilins (CyPs), two major CsA cellular targets. This suggested that instead, these compounds interacted directly with NTCP to inhibit viral attachment to host cells, and have no immunosuppressive function. Importantly, we found that SCY450 and SCY995 did not impair the NTCP-dependent uptake of bile acids, and inhibited multiple HBV genotypes including a clinically relevant nucleoside analog-resistant HBV isolate. This is the first example of small molecule selective inhibition of HBV entry with no decrease in NTCP transporter activity. It suggests that the anti-HBV activity can be functionally separated from bile acid transport. These broadly active anti-HBV molecules are potential candidates for developing new drugs with fewer adverse effects. In this study, we identified new compounds that selectively inhibited hepatitis B virus (HBV) entry, and did not impair bile acid uptake. Our evidence offers a new strategy for developing anti-HBV drugs with fewer side effects. Copyright © 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Reduction in fecal excretion of Giardia cysts: effect of cholestasis and diet.

PubMed

Erlandsen, Stanley

2005-12-01

Bile is a major growth factor for the proliferation of Giardia spp. trophozoites in the small intestine and, at high concentrations, stimulates encystment of trophozoites. This report demonstrates that surgical cholestasis to interrupt the flow of bile from liver to intestine or the use of bile-binding resins in the diet can both dramatically decrease the fecal excretion of Giardia muris cysts. Cholestasis produced a 3 log reduction in excretion of G. muris cysts within 24 hr of surgery and a 4 log reduction after 3 days. Sham controls showed no difference in cyst excretion from presurgical control values. Two isocaloric diets were studied: a control diet (N) of Purina mouse chow containing 5% celufil and an experimental diet (CR) containing 5% cholestyramine, a resin that binds bile. Compared with the N diet, the CR diet was associated with reductions in cyst excretion of 3 logs within 1 day. Despite lowered excretion of G. muris cysts in mice fed the cholestyramine diet, the trophozoite recovery from the duodenum was similar with both diets. Cyclic feeding of the CR diet and the N diet at 3-day intervals produced significant oscillations (changes of 3-4 logs) in fecal cyst shedding. The significant reductions in fecal excretion of cysts observed with agents that bind bile suggests that diets capable of binding bile might be a therapeutic means to minimize the fecal excretion of cysts and thereby may help to reduce the risk of spreading giardiasis through fecal-oral contamination.

Olfactory sensitivity of Pacific Lampreys to lamprey bile acids

USGS Publications Warehouse

Robinson, T. Craig; Sorensen, Peter W.; Bayer, Jennifer M.; Seelye, James G.

2009-01-01

Pacific lampreys Lampetra tridentata are in decline throughout much of their historical range in the Columbia River basin. In support of restoration efforts, we tested whether larval and adult lamprey bile acids serve as migratory and spawning pheromones in adult Pacific lampreys, as they do in sea lampreys Petromyzon marinus. The olfactory sensitivity of adult Pacific lampreys to lamprey bile acids was measured by electro-olfactogram recording from the time of their capture in the spring until their spawning in June of the following year. As controls, we tested L-arginine and a non-lamprey bile acid, taurolithocholic acid 3-sulfate (TLS). Migrating adult Pacific lampreys were highly sensitive to petromyzonol sulfate (a component of the sea lamprey migratory pheromone) and 3-keto petromyzonol sulfate (a component of the sea lamprey sex pheromone) when first captured. This sensitivity persisted throughout their long migratory and overwinter holding period before declining to nearly unmeasurable levels by the time of spawning. The absolute magnitudes of adult Pacific lamprey responses to lamprey bile acids were smaller than those of the sea lamprey, and unlike the sea lamprey, the Pacific lamprey did not appear to detect TLS. No sexual dimorphism was noted in olfactory sensitivity. Thus, Pacific lampreys are broadly similar to sea lampreys in showing sensitivity to the major lamprey bile acids but apparently differ in having a longer period of sensitivity to those acids. The potential utility of bile acid-like pheromones in the restoration of Pacific lampreys warrants their further investigation in this species.

Nuclear receptors in bile acid metabolism

PubMed Central

Li, Tiangang; Chiang, John Y. L.

2013-01-01

Bile acids are signaling molecules that activate nuclear receptors, such as farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, and vitamin D receptor, and play a critical role in the regulation of lipid, glucose, energy, and drug metabolism. These xenobiotic/endobiotic-sensing nuclear receptors regulate phase I oxidation, phase II conjugation, and phase III transport in bile acid and drug metabolism in the digestive system. Integration of bile acid metabolism with drug metabolism controls absorption, transport, and metabolism of nutrients and drugs to maintain metabolic homeostasis and also protects against liver injury, inflammation, and related metabolic diseases, such as nonalcoholic fatty liver disease, diabetes, and obesity. Bile-acid–based drugs targeting nuclear receptors are in clinical trials for treating cholestatic liver diseases and fatty liver disease. PMID:23330546

Bile acids modulate glucocorticoid metabolism and the hypothalamic–pituitary–adrenal axis in obstructive jaundice☆

PubMed Central

McNeilly, Alison D.; Macfarlane, David P.; O’Flaherty, Emmett; Livingstone, Dawn E.; Mitić, Tijana; McConnell, Kirsty M.; McKenzie, Scott M.; Davies, Eleanor; Reynolds, Rebecca M.; Thiesson, Helle C.; Skøtt, Ole; Walker, Brian R.; Andrew, Ruth

2010-01-01

Background & Aims Suppression of the hypothalamic–pituitary–adrenal axis occurs in cirrhosis and cholestasis and is associated with increased concentrations of bile acids. We investigated whether this was mediated through bile acids acting to impair steroid clearance by inhibiting glucocorticoid metabolism by 5β-reductase. Methods The effect of bile acids on glucocorticoid metabolism was studied in vitro in hepatic subcellular fractions and hepatoma cells, allowing quantitation of the kinetics and transcript abundance of 5β-reductase. Metabolism was subsequently examined in vivo in rats following dietary manipulation or bile duct ligation. Finally, glucocorticoid metabolism was assessed in humans with obstructive jaundice. Results In rat hepatic cytosol, chenodeoxycholic acid competitively inhibited 5β-reductase (Ki 9.19 ± 0.40 μM) and reduced its transcript abundance (in H4iiE cells) and promoter activity (reporter system, HepG2 cells). In Wistar rats, dietary chenodeoxycholic acid (1% w/w chow) inhibited hepatic 5β-reductase activity, reduced urinary excretion of 3α,5β-tetrahydrocorticosterone and reduced adrenal weight. Conversely, a fat-free diet suppressed bile acid levels and increased hepatic 5β-reductase activity, supplementation of the fat-free diet with CDCA reduced 5β-reductase activity, and urinary 3α,5β-reduced corticosterone. Cholestasis in rats suppressed hepatic 5β-reductase activity and transcript abundance. In eight women with obstructive jaundice, relative urinary excretion of 3α,5β-tetrahydrocortisol was significantly lower than in healthy controls. Conclusion These data suggest a novel role for bile acids in inhibiting hepatic glucocorticoid clearance, of sufficient magnitude to suppress hypothalamic–pituitary–adrenal axis activity. Elevated hepatic bile acids may account for adrenal insufficiency in liver disease. PMID:20347173

Effect of ursodeoxycholic acid on bile acid profiles and intestinal detoxification machinery in primary biliary cirrhosis and health.

PubMed

Dilger, Karin; Hohenester, Simon; Winkler-Budenhofer, Ursula; Bastiaansen, Barbara A J; Schaap, Frank G; Rust, Christian; Beuers, Ulrich

2012-07-01

Ursodeoxycholic acid (UDCA) exerts anticholestatic, antifibrotic and antiproliferative effects in primary biliary cirrhosis (PBC) via mechanisms not yet fully understood. Its adequate biliary enrichment is considered mandatory for therapeutic efficacy. However, precise determination of biliary enrichment of UDCA is not possible in clinical practice. Therefore, we investigated (i) the relationship between biliary enrichment and plasma pharmacokinetics of UDCA, (ii) the effect of UDCA on plasma and biliary bile acid composition and conjugation patterns, and (iii) on the intestinal detoxification machinery in patients with PBC and healthy controls. In 11 PBC patients and 11 matched healthy subjects, cystic bile and duodenal tissue were collected before and after 3 weeks of administration of UDCA (15 mg/kg/day). Extensive pharmacokinetic profiling of bile acids was performed. The effect of UDCA on the intestinal detoxification machinery was studied by quantitative PCR and Western blotting. The relative fraction of UDCA and its conjugates in plasma at trough level[x] correlated with their biliary enrichment[y] (r=0.73, p=0.0001, y=3.65+0.49x). Taurine conjugates of the major hydrophobic bile acid, chenodeoxycholic acid, were more prominent in bile of PBC patients than in that of healthy controls. Biliary bile acid conjugation patterns normalized after treatment with UDCA. UDCA induced duodenal expression of key export pumps, BCRP and P-glycoprotein. Biliary and trough plasma enrichment of UDCA are closely correlated in PBC and health. Taurine conjugation may represent an adaptive mechanism in PBC against chenodeoxycholic acid-mediated bile duct damage. UDCA may stabilize small intestinal detoxification by upregulation of efflux pumps. Copyright © 2012. Published by Elsevier B.V.

Potential bile acid metabolites. XV. Synthesis of 4 beta-hydroxylated bile acids; unique bile acids in human fetal bile.

PubMed

Iida, T; Momose, T; Chang, F C; Goto, J; Nambara, T

1989-12-01

The 4 beta-hydroxylated derivatives of lithocholic, deoxycholic, chenodeoxycholic, and cholic acids were synthesized from their respective parent compounds. The principal reactions employed were 1) beta-face cis-dihydroxylation of delta 3 intermediates with osmium tetroxide-N-methylmorpholine N-oxide, 2) selective cathylation of vicinal 3 beta,4 beta-diols followed by oxidation of the resulting 4 beta-monocathylates, or direct selective oxidation at C-3 of 3 beta,4 beta-diols with pyridinium chlorochromate, and 3) stereoselective reduction of the 3-oxo compounds with tert-butylamine-borane complex. The results of analysis of the prepared 4 beta-hydroxylated bile acids with a diequatorial trans-glycol structure and their 3 beta-epimers by proton and carbon-13 nuclear magnetic resonance spectroscopies are briefly discussed along with the mass spectrometric properties.

Lithocholic acid is an endogenous inhibitor of MDM4 and MDM2

PubMed Central

Vogel, Simon M.; Bauer, Matthias R.; Joerger, Andreas C.; Wilcken, Rainer; Brandt, Tobias; Veprintsev, Dmitry B.; Rutherford, Trevor J.; Fersht, Alan R.; Boeckler, Frank M.

2012-01-01

The proteins MDM2 and MDM4 are key negative regulators of the tumor suppressor protein p53, which are frequently upregulated in cancer cells. They inhibit the transactivation activity of p53 by binding separately or in concert to its transactivation domain. MDM2 is also a ubiquitin ligase that leads to the degradation of p53. Accordingly, MDM2 and MDM4 are important targets for drugs to inhibit their binding to p53. We found from in silico screening and confirmed by experiment that lithocholic acid (LCA) binds to the p53 binding sites of both MDM2 and MDM4 with a fivefold preference for MDM4. LCA is an endogenous steroidal bile acid, variously reported to have both carcinogenic and apoptotic activities. The comparison of LCA effects on apoptosis in HCT116 p53+/+ vs. p53-/- cells shows a predominantly p53-mediated induction of caspase-3/7. The dissociation constants are in the μM region, but only modest inhibition of binding of MDM2 and MDM4 is required to negate their upregulation because they have to compete with transcriptional coactivator p300 for binding to p53. Binding was weakened by structural changes in LCA, and so it may be a natural ligand of MDM2 and MDM4, raising the possibility that MDM proteins may be sensors for specific steroids. PMID:23035244

Two Major Bile Acids in the Hornbills, (24R,25S)-3α,7α,24-Trihydroxy-5β-cholestan-27-oyl Taurine and Its 12α-Hydroxy Derivative.

PubMed

Satoh, Rika; Ogata, Hiroaki; Saito, Tetsuya; Zhou, Biao; Omura, Kaoru; Kurabuchi, Satoshi; Mitamura, Kuniko; Ikegawa, Shigeo; Hagey, Lee R; Hofmann, Alan F; Iida, Takashi

2016-06-01

Two major bile acids were isolated from the gallbladder bile of two hornbill species from the Bucerotidae family of the avian order Bucerotiformes Buceros bicornis (great hornbill) and Penelopides panini (Visayan tarictic hornbill). Their structures were determined to be 3α,7α,24-dihydroxy-5β-cholestan-27-oic acid and its 12α-hydroxy derivative, 3α,7α,12α,24-tetrahydroxy-5β-cholestan-27-oic acid (varanic acid, VA), both present in bile as their corresponding taurine amidates. The four diastereomers of varanic acid were synthesized and their assigned structures were confirmed by X-ray crystallographic analysis. VA and its 12-deoxy derivative were found to have a (24R,25S)-configuration. 13 additional hornbill species were also analyzed by HPLC and showed similar bile acid patterns to B. bicornis and P. panini. The previous stereochemical assignment for (24R,25S)-VA isolated from the bile of varanid lizards and the Gila monster should now be revised to the (24S,25S)-configuration.

Pleiotropic Roles of Bile Acids in Metabolism

PubMed Central

de Aguiar Vallim, Thomas Q.; Tarling, Elizabeth J.; Edwards, Peter A.

2013-01-01

Summary Enzymatic oxidation of cholesterol generates numerous distinct bile acids that function both as detergents that facilitate digestion and absorption of dietary lipids, and as hormones that activate four distinct receptors. Activation of these receptors alters gene expression in multiple tissues leading to changes not only in bile acid metabolism, but also in glucose homeostasis, lipid and lipoprotein metabolism, energy expenditure, intestinal motility and bacterial growth, inflammation, liver regeneration and hepato-carcinogenesis. This review covers the roles of specific bile acids, synthetic agonists and their cognate receptors in controlling these diverse functions, as well as their current use in treating human diseases. PMID:23602448

Assay of free and glycine- and taurine-conjugated bile acids in serum by high-pressure liquid chromatography by using post-column reaction after group separation.

PubMed Central

Onishi, S; Itoh, S; Ishida, Y

1982-01-01

An accurate and sensitive method that involves the group separations of serum bile acids (i.e. free and glycine- and taurine-conjugated bile acid fractions) by ion-exchange chromatography on piperidinohydroxypropyl-Sephadex LH-20 is described. Each group was then analysed by high-pressure liquid chromatography by using the post-column reaction technique with immobilized 3 alpha-hydroxy steroid dehydrogenase. The bile acid patterns in the umbilical venous serum samples were analysed by this method. Taurochenodeoxycholate predominated in the umbilical blood. PMID:6956336

Hepatobiliary transport kinetics of the conjugated bile acid tracer 11C-CSar quantified in healthy humans and patients by positron emission tomography.

PubMed

Ørntoft, Nikolaj Worm; Munk, Ole Lajord; Frisch, Kim; Ott, Peter; Keiding, Susanne; Sørensen, Michael

2017-08-01

Hepatobiliary secretion of bile acids is an important liver function. Here, we quantified the hepatic transport kinetics of conjugated bile acids using the bile acid tracer [N-methyl- 11 C]cholylsarcosine ( 11 C-CSar) and positron emission tomography (PET). Nine healthy participants and eight patients with varying degrees of cholestasis were examined with 11 C-CSar PET and measurement of arterial and hepatic venous blood concentrations of 11 C-CSar. Results are presented as median (range). The hepatic intrinsic clearance was 1.50 (1.20-1.76) ml blood/min/ml liver tissue in healthy participants and 0.46 (0.13-0.91) in patients. In healthy participants, the rate constant for secretion of 11 C-CSar from hepatocytes to bile was 0.36 (0.30-0.62)min -1 , 20 times higher than the rate constant for backflux from hepatocytes to blood (0.02, 0.005-0.07min -1 ). In the patients, rate constant for transport from hepatocyte to bile was reduced to 0.12 (0.006-0.27)min -1 , 2.3times higher than the rate constant for backflux to blood (0.05, 0.04-0.09). The increased backflux did not fully normalize exposure of the hepatocyte to bile acids as mean hepatocyte residence time of 11 C-CSar was 2.5 (1.6-3.1)min in healthy participants and 6.4 (3.1-23.7)min in patients. The rate constant for transport of 11 C-CSar from intrahepatic to extrahepatic bile was 0.057 (0.023-0.11)min -1 in healthy participants and only slightly reduced in patients 0.039 (0.017-0.066). This first in vivo quantification of individual steps involved in the hepatobiliary secretion of a conjugated bile acid in humans provided new insight into cholestatic disease. Positron emission tomography (PET) using the radiolabelled bile acid ( 11 C-CSar) enabled quantification of the individual steps of the hepatic transport of bile acids from blood to bile in man. Cholestasis reduced uptake and secretion and increased backflux to blood. These findings improve our understanding of cholestatic liver diseases and may support therapeutic decisions. The trial is registered at ClinicalTrials.gov (NCT01879735). Copyright © 2017 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Systematic review: the prevalence of idiopathic bile acid malabsorption as diagnosed by SeHCAT scanning in patients with diarrhoea-predominant irritable bowel syndrome.

PubMed

Wedlake, L; A'Hern, R; Russell, D; Thomas, K; Walters, J R F; Andreyev, H J N

2009-10-01

Recurrent, watery diarrhoea affects one-third of patients diagnosed with irritable bowel syndrome ('IBS-D'). Idiopathic bile acid malabsorption ('I-BAM') may be the cause. To determine the prevalence of I-BAM in patients suffering from IBS-D. A systematic search was performed of publications reporting patients presenting with IBS-D type symptoms, who were subsequently confirmed as having I-BAM by SeHCAT scanning. Eighteen relevant studies, 15 prospective, comprising 1223 patients were identified. Five studies (429 patients) indicated that 10% (CI: 7-13) patients had severe bile acid malabsorption (SeHCAT 7 day retention <5% of baseline value). 17 studies (1073 patients) indicated that 32% (CI: 29-35) patients had moderate bile acid malabsorption (SeHCAT <10%). 7 studies (618 patients) indicated that 26% (CI: 23-30) patients had mild (SeHCAT <15%) bile acid malabsorption. Pooled data from 15 studies showed a dose-response relationship according to severity of malabsorption to treatment with a bile acid binder: response to colestyramine occurred in 96% of patients with <5% retention, 80% at <10% retention and 70% at <15% retention. Idiopathic adult-onset bile acid malabsorption is not rare. International guidelines for the management of irritable bowel syndrome need to be revised so that clinicians become more aware of this possibility.

Synthesis of the 3-sulfates of S-acyl glutathione conjugated bile acids and their biotransformation by a rat liver cytosolic fraction.

PubMed

Mitamura, Kuniko; Hori, Naohiro; Mino, Shiori; Iida, Takashi; Hofmann, Alan F; Ikegawa, Shigeo

2012-04-01

The 3-sulfates of the S-acyl glutathione (GSH) conjugates of five natural bile acids (cholic, chenodeoxycholic, deoxycholic, ursodeoxycholic, and lithocholic) were synthesized as reference standards in order to investigate their possible formation by a rat liver cytosolic fraction. Their structures were confirmed by proton nuclear magnetic resonance, as well as by means of electrospray ionization-linear ion-trap mass spectrometry with negative-ion detection. Upon collision-induced dissociation, structurally informative product ions were observed. Using a triple-stage quadrupole instrument, selected reaction monitoring analyses by monitoring characteristic transition ions allowed the achievement of a highly sensitive and specific assay. This method was used to determine whether the 3-sulfates of the bile acid-GSH conjugates (BA-GSH) were formed when BA-GSH were incubated with a rat liver cytosolic fraction to which 3'-phosphoadenosine 5'-phosphosulfate had been added. The S-acyl linkage was rapidly hydrolyzed to form the unconjugated bile acid. A little sulfation of the GSH conjugates occurred, but greater sulfation at C-3 of the liberated bile acid occurred. Sulfation was proportional to the hydrophobicity of the unconjugated bile acid. Thus GSH conjugates of bile acids as well as their C-3 sulfates if formed in vivo are rapidly hydrolyzed by cytosolic enzymes. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Effects of Bile Acids and Nisin on the Production of Enterotoxin by Clostridium perfringens in a Nutrient-Rich Medium

PubMed Central

Park, Miseon

2018-01-01

Clostridium perfringens is the second most common cause of bacterial foodborne illness in the United States, with nearly a million cases each year. C. perfringens enterotoxin (CPE), produced during sporulation, damages intestinal epithelial cells by pore formation, which results in watery diarrhea. The effects of low concentrations of nisin and bile acids on sporulation and toxin production were investigated in C. perfringens SM101, which carries an enterotoxin gene on the chromosome, in a nutrient-rich medium. Bile acids and nisin increased production of enterotoxin in cultures; bile acids had the highest effect. Both compounds stimulated the transcription of enterotoxin and sporulation-related genes and production of spores during the early growth phase. They also delayed spore outgrowth and nisin was more inhibitory. Bile acids and nisin enhanced enterotoxin production in some but not all other C. perfringens isolates tested. Low concentrations of bile acids and nisin may act as a stress signal for the initiation of sporulation and the early transcription of sporulation-related genes in some strains of C. perfringens, which may result in increased strain-specific production of enterotoxin in those strains. This is the first report showing that nisin and bile acids stimulated the transcription of enterotoxin and sporulation-related genes in a nutrient-rich bacterial culture medium. PMID:29675044

Long-term serum bile acid concentrations in 51 dogs after complete extrahepatic congenital portosystemic shunt ligation.

PubMed

Bristow, P; Tivers, M; Packer, R; Brockman, D; Ortiz, V; Newson, K; Lipscomb, V

2017-08-01

To report the long-term bile acid stimulation test results for dogs that have undergone complete suture ligation of a single congenital extrahepatic portosystemic shunt. Data were collected from the hospital records of all dogs that had undergone a complete suture ligation of a single congenital extrahepatic portosystemic shunt. Owners were invited to return to the referral centre or their local veterinarian for repeat serum bile acid measurement. Dogs diagnosed with idiopathic epilepsy and undergoing bile acid stimulation tests were used as a comparison population. Fifty-one study dogs were included, with a mean follow-up time of 62 months. 48 dogs had no evidence of multiple acquired shunts and a significant reduction in the pre- and post-prandial serum bile acid concentrations at long-term follow-up compared with pre-operative measurements. Pre- and post-prandial serum bile acids were statistically significantly greater for dogs that had undergone a full ligation (with no evidence of multiple acquired shunts) at all time points compared to the control dogs (P<0·001 for all comparisons). The results suggest that in dogs treated with complete suture ligation mild increases in serum bile acids are not clinically relevant if there are no physical examination abnormalities, a normal body condition score and no relapse in clinical signs. © 2017 British Small Animal Veterinary Association.

The mechanism of enterohepatic circulation in the formation of gallstone disease.

PubMed

Cai, Jian-Shan; Chen, Jin-Hong

2014-11-01

Bile acids entering into enterohepatic circulating are primary acids synthesized from cholesterol in hepatocyte. They are secreted actively across canalicular membrane and carried in bile to gallbladder, where they are concentrated during digestion. About 95% BAs are actively taken up from the lumen of terminal ileum efficiently, leaving only approximately 5% (or approximately 0.5 g/d) in colon, and a fraction of bile acids are passively reabsorbed after a series of modifications in the human large intestine including deconjugation and oxidation of hydroxy groups. Bile salts hydrolysis and hydroxy group dehydrogenation reactions are performed by a broad spectrum of intestinal anaerobic bacteria. Next, hepatocyte reabsorbs bile acids from sinusoidal blood, which are carried to liver through portal vein via a series of transporters. Bile acids (BAs) transporters are critical for maintenance of the enterohepatic BAs circulation, where BAs exert their multiple physiological functions including stimulation of bile flow, intestinal absorption of lipophilic nutrients, solubilization, and excretion of cholesterol. Tight regulation of BA transporters via nuclear receptors (NRs) is necessary to maintain proper BA homeostasis. In conclusion, disturbances of enterohepatic circulation may account for pathogenesis of gallstones diseases, including BAs transporters and their regulatory NRs and the metabolism of intestinal bacterias, etc.

DAX1 suppresses FXR transactivity as a novel co-repressor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jin; Lu, Yan; Liu, Ruya

2011-09-09

Highlights: {yields} DAX1 is co-localized with FXR and interacts with FXR. {yields} DAX1 acts as a negative regulator of FXR. {yields} Three LXXLL motifs in the N-terminus of DAX1 were required. {yields} DAX1 suppresses FXR transactivation by competing with co-activators. -- Abstract: Bile acid receptor FXR (farnesoid X receptor) is a key regulator of hepatic bile acid, glucose and lipid homeostasis through regulation of numerous genes involved in the process of bile acid, triglyceride and glucose metabolism. DAX1 (dosage-sensitive sex reversal adrenal hypoplasia congenital critical region on X chromosome, gene 1) is an atypical member of the nuclear receptor familymore » due to lack of classical DNA-binding domains and acts primarily as a co-repressor of many nuclear receptors. Here, we demonstrated that DAX1 is co-localized with FXR in the nucleus and acted as a negative regulator of FXR through a physical interaction with FXR. Our study showed that over-expression of DAX1 down-regulated the expression of FXR target genes, whereas knockdown of DAX1 led to their up-regulation. Furthermore, three LXXLL motifs in the N-terminus of DAX1 were required for the full repression of FXR transactivation. In addition, our study characterized that DAX1 suppresses FXR transactivation via competing with co-activators such as SRC-1 and PGC-1{alpha}. In conclusion, DAX1 acts as a co-repressor to negatively modulate FXR transactivity.« less

The fat and protein fractions of freshwater clam ( Corbicula fluminea) extract reduce serum cholesterol and enhance bile acid biosynthesis and sterol excretion in hypercholesterolaemic rats fed a high-cholesterol diet.

PubMed

Chijimatsu, Takeshi; Umeki, Miki; Okuda, Yuji; Yamada, Koji; Oda, Hiroaki; Mochizuki, Satoshi

2011-02-01

We investigated whether the fat and protein fractions of freshwater clam (Corbicula fluminea) extract (FCE) could ameliorate hypercholesterolaemia in rats fed a high-cholesterol diet. We also explored the mechanism and the components that exert the hypocholesterolaemic effect of FCE. The doses of the fat and protein fractions were equivalent to those in 30 % FCE. The fat and protein fractions of FCE, two major components of FCE, significantly reduced the serum and hepatic cholesterol levels. The fat fraction more strongly reduced serum cholesterol levels than the same level of total FCE. The excretion of faecal neutral sterols increased in rats fed the total the FCE and the fat fraction of FCE. On the other hand, faecal bile acid levels were greater in rats fed the total FCE and the fat and protein fractions of FCE than in control animals. The hepatic gene expression of ATP-binding cassette transporter G5 and cholesterol 7α-hydroxylase was up-regulated by the administration of the total FCE and both the fat and protein fractions of FCE. These results showed that the fat and protein fractions of FCE had hypocholesterolaemic properties, and that these effects were greater with the fat fraction than with the protein fraction. The present study indicates that FCE exerts its hypocholesterolaemic effects through at least two different mechanisms, including enhanced excretion of neutral sterols and up-regulated biosynthesis of bile acids.

[Results of the 75selenium homotaurocholic acid retention test (SeHCAT test) in diagnosis of diarrhea].

PubMed

Balzer, K; Schmitt, G; Reiners, C; Goebell, H

1995-01-15

For that reason absorption of bile acids was investigated using the 75Se-homotaurocholate (SeHCAT) in 239 patients with diarrhoea. SeHCAT retention time was measured as 7 day retention time in a whole body counter. An intact bile acid absorption (negative SeHCAT test) was confirmed in 23 healthy volunteers within the range of 11 to 50% (mean +/- double standard deviation). In 135 patients with a possible type I bile salt malabsorption the SeHCAT test was positive in 78%, thus indicating bile salt malabsorption. The test is very sensitive detecting bile salt malabsorption in Crohn's disease, identifying ileal disease more precisely than radiology. The SeHCAT test ascertained type II primary bile salt malabsorption in 7 patients, as well as type III bile salt malabsorption in patients (9 out of 28) with cholecystectomy, vagotomy, partial gastrectomy and chronic pancreatitis. In addition, a positive SeHCAT test indicating bile acid malabsorption was found in 5 out of 11 patients with irritable syndrome, diarrhoeic form, and in 4 out of 12 patients with lactose intolerance. SeHCAT retention should be measured routinely in patients with chronic diarrhoea for which the cause is not obvious.

Idiopathic bile acid malabsorption: qualitative and quantitative clinical features and response to cholestyramine.

PubMed

Sinha, L; Liston, R; Testa, H J; Moriarty, K J

1998-09-01

Idiopathic bile acid malabsorption is a poorly recognized cause of chronic diarrhoea. The SeHCAT (75Selenium HomotauroCholic Acid Test) can accurately diagnose this condition. To identify patients with idiopathic bile acid malabsorption, to describe their clinical features, both qualitatively and quantitatively, and to assess the response to cholestyramine. Idiopathic bile acid malabsorption was considered in all patients complaining of chronic diarrhoea. They were included in the study if their SeHCATs were positive (< 15% retention) and secondary causes of bile acid malabsorption were excluded. The response to therapy with cholestyramine was assessed. Nine patients were diagnosed with idiopathic bile acid malabsorption (median SeHCAT retention 8%, range 3-12.6). Their median daily faecal weight was 285 g (range 85-676) and median faecal fat output was 17 mmol/24 h (range 8.3-38.8). Six patients had an immediate response to cholestyramine. There was a marked reduction in stool frequency (median stool frequency pre-treatment 5/day vs. 2/day post-treatment, P = 0.03). Five patients had large volume diarrhoea (faecal weight > 200 g/day) and three had steatorrhoea. Idiopathic bile acid malabsorption, once suspected, especially by documenting true 'large volume' watery diarrhoea or steatorrhoea, is easily diagnosed and response to therapy is often very good. There is often a previous history of gastrointestinal infection and this condition should be considered in patients with chronic diarrhoea of undetermined origin, especially before they are labelled as having irritable bowel syndrome.

Bile acid metabolism regulated by the gut microbiota promotes non-alcoholic steatohepatitis-associated hepatocellular carcinoma in mice

PubMed Central

Yamada, Shoji; Takashina, Yoko; Watanabe, Mitsuhiro; Nagamine, Ryogo; Saito, Yoshimasa; Kamada, Nobuhiko; Saito, Hidetsugu

2018-01-01

Gut microbiota plays a significant role in the development of hepatocellular carcinoma (HCC) in non-alcoholic steatohepatitis (NASH). However, understanding of the precise mechanism of this process remains incomplete. A new class steatohepatitis-inducing high-fat diet (HFD), namely STHD-01, can promote the development of HCC without the administration of chemical carcinogens. Using this diet, we comprehensively analyzed changes in the gut microbiota and its metabolic functions during the development of HCC in NASH. Mice fed the STHD-01 developed NASH within 9 weeks. NASH further progressed into HCC by 41 weeks. Treatment with antibiotics significantly attenuated liver pathology and suppressed tumor development, indicating the critical role of the gut microbiota in tumor development in this model. Accumulation of cholesterol and bile acids in the liver and feces increased after feeding the mice with STHD-01. Treatment with antibiotics did not reverse these phenotypes. In contrast, accumulation of secondary bile acids was dramatically reduced after the treatment with antibiotics, suggesting the critical role of the gut microbiota in the conversion of primary bile acids to secondary bile acids. Secondary bile acids such as deoxycholic acid activated the mTOR, pathway in hepatocytes. Activation of mTOR was observed in the liver of mice fed STHD-01, and the activation was reduced when mice were treated with antibiotics. Collectively, bile acid metabolism by the gut microbiota promotes HCC development in STHD-01-induced NASH. PMID:29515780

Diet1, bile acid diarrhea, and FGF15/19: mouse model and human genetic variants.

PubMed

Lee, Jessica M; Ong, Jessica R; Vergnes, Laurent; de Aguiar Vallim, Thomas Q; Nolan, Jonathan; Cantor, Rita M; Walters, Julian R F; Reue, Karen

2018-03-01

Diet1 modulates intestinal production of the hormone, fibroblast growth factor (FGF)15, which signals in liver to regulate bile acid synthesis. C57BL/6ByJ mice with a spontaneous Diet1 -null mutation are resistant to hypercholesterolemia compared with wild-type C57BL/6J mice through enhanced cholesterol conversion to bile acids. To further characterize the role of Diet1 in metabolism, we generated Diet1 -/- mice on the C57BL/6J genetic background. C57BL/6J Diet1 -/- mice had elevated bile acid levels, reduced Fgf15 expression, and increased gastrointestinal motility and intestinal luminal water content, which are symptoms of bile acid diarrhea (BAD) in humans. Natural genetic variation in Diet1 mRNA expression levels across 76 inbred mouse strains correlated positively with Ffg15 mRNA and negatively with serum bile acid levels. This led us to investigate the role of DIET1 genetic variation in primary BAD patients. We identified a DIET1 coding variant ( rs12256835 ) that had skewed prevalence between BAD cases and controls. This variant causes an H1721Q amino acid substitution that increases the levels of FGF19 protein secreted from cultured cells. We propose that genetic variation in DIET1 may be a determinant of FGF19 secretion levels, and may affect bile acid metabolism in both physiological and pathological conditions. Copyright © 2018 by the American Society for Biochemistry and Molecular Biology, Inc.

Molecular cloning, characterization and comparison of bile salt hydrolases from Lactobacillus johnsonii PF01.

PubMed

Chae, J P; Valeriano, V D; Kim, G-B; Kang, D-K

2013-01-01

To clone, characterize and compare the bile salt hydrolase (BSH) genes of Lactobacillus johnsonii PF01. The BSH genes were amplified by polymerase chain reaction (PCR) using specific oligonucleotide primers, and the products were inserted into the pET21b expression vector. Escherichia coli BLR (DE3) cells were transformed with pET21b vectors containing the BSH genes and induced using 0·1 mmol l(-1) isopropylthiolgalactopyranoside. The overexpressed BSH enzymes were purified using a nickel-nitrilotriacetic acid (Ni(2+) -NTA) agarose column and their activities characterized. BSH A hydrolysed tauro-conjugated bile salts optimally at pH 5·0 and 55°C, whereas BSH C hydrolysed glyco-conjugated bile salts optimally at pH 5·0 and 70°C. The enzymes had no preferential activities towards a specific cholyl moiety. BSH enzymes vary in their substrate specificities and characteristics to broaden its activity. Despite the lack of conservation in their putative substrate-binding sites, these remain functional through motif conservation. This is to our knowledge the first report of isolation of BSH enzymes from a single strain, showing hydrolase activity towards either glyco-conjugated or tauro-conjugated bile salts. Future structural homology studies and site-directed mutagenesis of sites associated with substrate specificity may elucidate specificities of BSH enzymes. © 2012 The Society for Applied Microbiology.

Inhibition of NF-κB prevents the acidic bile-induced oncogenic mRNA phenotype, in human hypopharyngeal cells

PubMed Central

Vageli, Dimitra P.; Doukas, Sotirios G.; Sasaki, Clarence T.

2018-01-01

Bile-containing gastro-duodenal reflux has been clinically considered an independent risk factor in hypopharyngeal carcinogenesis. We recently showed that the chronic effect of acidic bile, at pH 4.0, selectively induces NF-κB activation and accelerates the transcriptional levels of genes, linked to head and neck cancer, in normal hypopharyngeal epithelial cells. Here, we hypothesize that NF-κB inhibition is capable of preventing the acidic bile-induced and cancer-related mRNA phenotype, in treated normal human hypopharyngeal cells. In this setting we used BAY 11-7082, a specific and well documented pharmacologic inhibitor of NF-κB, and we observed that BAY 11-7082 effectively inhibits the acidic bile-induced gene expression profiling of the NF-κB signaling pathway (down-regulation of 72 out of 84 analyzed genes). NF-κB inhibition significantly prevents the acidic bile-induced transcriptional activation of NF-κB transcriptional factors, RELA (p65) and c-REL, as well as genes related to and commonly found in established HNSCC cell lines. These include anti-apoptotic bcl-2, oncogenic STAT3, EGFR, ∆Np63, TNF-α and WNT5A, as well as cytokines IL-1β and IL-6. Our findings are consistent with our hypothesis demonstrating that NF-κB inhibition effectively prevents the acidic bile-induced cancer-related mRNA phenotype in normal human hypopharyngeal epithelial cells supporting an understanding that NF-κB may be a critical link between acidic bile and early preneoplastic events in this setting. PMID:29464041

Normal reference intervals and the effects of time and feeding on serum bile acid concentrations in llamas.

PubMed

Andreasen, C B; Pearson, E G; Smith, B B; Gerros, T C; Lassen, E D

1998-04-01

Fifty clinically healthy llamas, 0.5-13 years of age (22 intact males, 10 neutered males, 18 females), with no biochemical evidence of liver disease or hematologic abnormalities, were selected to establish serum bile acid reference intervals. Serum samples submitted to the clinical pathology laboratory were analyzed using a colorimetric enzymatic assay to establish bile acid reference intervals. A nonparametric distribution of llama bile acid concentrations was 1-23 micromol/liter for llamas >1 year of age and 10-44 micromol/liter for llamas < or = 1 year of age. A significant difference was found between these 2 age groups. No correlation was detected between gender and bile acid concentrations. The reference intervals were 1.1-22.9 micromol/liter for llamas >1 year of age and 1.8-49.8 micromol/liter for llamas < or = 1 year of age. Additionally, a separate group of 10 healthy adult llamas (5 males, 5 females, 5-11 years of age) without biochemical or hematologic abnormalities was selected to assess the effects of feeding and time intervals on serum bile acid concentrations. These 10 llamas were provided fresh water and hay ad libitum, and serum samples were obtained via an indwelling jugular catheter hourly for 11 hours. Llamas were then kept from food overnight (12 hours), and subsequent samples were taken prior to feeding (fasting baseline time, 23 hours after trial initiation) and postprandially at 0.5, 1, 2, 4, and 8 hours. In feeding trials, there was no consistent interaction between bile acid concentrations and time, feeding, or 12-hour fasting. Prior feeding or time of day did not result in serum bile acid concentrations outside the reference interval, but concentrations from individual llamas varied within this interval over time.

Identification of a novel bile acid in swans, tree ducks, and geese: 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid.

PubMed

Kakiyama, Genta; Iida, Takashi; Goto, Takaaki; Mano, Nariyasu; Goto, Junichi; Nambara, Toshio; Hagey, Lee R; Schteingart, Claudio D; Hofmann, Alan F

2006-07-01

By HPLC, a taurine-conjugated bile acid with a retention time different from that of taurocholate was found to be present in the bile of the black-necked swan, Cygnus melanocoryphus. The bile acid was isolated and its structure, established by (1)H and (13)C NMR and mass spectrometry, was that of the taurine N-acyl amidate of 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid. The compound was shown to have chromatographic and spectroscopic properties that were identical to those of the taurine conjugate of authentic 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid, previously synthesized by us from ursodeoxycholic acid. By HPLC, the taurine conjugate of 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid was found to be present in 6 of 6 species in the subfamily Dendrocygninae (tree ducks) and in 10 of 13 species in the subfamily Anserinae (swans and geese) but not in other subfamilies in the Anatidae family. It was also not present in species from the other two families of the order Anseriformes. 3alpha,7alpha,15alpha-Trihydroxy-5beta-cholan-24-oic acid is a new primary bile acid that is present in the biliary bile acids of swans, tree ducks, and geese and may be termed 15alpha-hydroxy-chenodeoxycholic acid.

Regulation of antibacterial defense in the small intestine by the nuclear bile acid receptor.

PubMed

Inagaki, Takeshi; Moschetta, Antonio; Lee, Youn-Kyoung; Peng, Li; Zhao, Guixiang; Downes, Michael; Yu, Ruth T; Shelton, John M; Richardson, James A; Repa, Joyce J; Mangelsdorf, David J; Kliewer, Steven A

2006-03-07

Obstruction of bile flow results in bacterial proliferation and mucosal injury in the small intestine that can lead to the translocation of bacteria across the epithelial barrier and systemic infection. These adverse effects of biliary obstruction can be inhibited by administration of bile acids. Here we show that the farnesoid X receptor (FXR), a nuclear receptor for bile acids, induces genes involved in enteroprotection and inhibits bacterial overgrowth and mucosal injury in ileum caused by bile duct ligation. Mice lacking FXR have increased ileal levels of bacteria and a compromised epithelial barrier. These findings reveal a central role for FXR in protecting the distal small intestine from bacterial invasion and suggest that FXR agonists may prevent epithelial deterioration and bacterial translocation in patients with impaired bile flow.

Intestinal absorption of the bile acid analogue 75Se-homocholic acid-taurine is increased in primary biliary cirrhosis, and reverts to normal during ursodeoxycholic acid administration.

PubMed

Lanzini, A; De Tavonatti, M G; Panarotto, B; Scalia, S; Mora, A; Benini, F; Baisini, O; Lanzarotto, F

2003-09-01

Whether ileal absorption of bile acid is up or downregulated in chronic cholestasis is still debated, and most evidence has come from animal studies. To compare ileal bile acid absorption in patients with primary biliary cirrhosis (PBC) and in healthy control subjects, and to assess the effect of ursodeoxycholic acid (UDCA). We studied 14 PBC patients before and during (n=11) UDCA administration, 14 healthy control subjects, and 14 Crohn's disease patients (as disease controls). We used cholescintigraphy to measure retention in the enterohepatic circulation over five successive days of the bile acid analogue (75)Se-homocholic acid-taurine ((75)SeHCAT) as an index of ileal bile acid absorption. Results were expressed as (75)SeHCAT fractional turnover rate (FTR) and t(1/2)12. (75)SeHCAT FTR was 0.19 (0.11)/day, 0.34 (0.11)/day (p<0.001), and 0.83 (0.32)/day in PBC patients, healthy controls (p<0.0001), and Crohn's patients (p<0.001), respectively, which increased to 0.36 (0.16)/day in PBC patients during UDCA treatment (p<0.005). (75)SeHCAT t(1/2)12 was 4.8 (2.1) days in PBC patients, 2.2 (0.5) days (p<0.001) in healthy controls, and 1.0 (0.5) days (p<0.001) in Crohn's disease patients. (75)SeHCAT t(1/2)12 decreased to 2.2 (0.93) days (p< 0.001) in PBC patients during UDCA treatment. Our results support the concept that ileal bile acid absorption is upregulated in PBC patients, and that this effect may contribute towards damaging the cholestatic liver. This upregulation of bile acid absorption is abolished by UDCA.

Biliary Bile Acids in Primary Biliary Cirrhosis: Effect of Ursodeoxycholic Acid

PubMed Central

Combes, Burton; Carithers, Robert L.; Maddrey, Willis C.; Munoz, Santiago; Garcia-Tsao, Guadalupe; Bonner, Gregory F.; Boyer, James L.; Luketic, Velimir A.; Shiffman, Mitchell L.; Peters, Marion G.; White, Heather; Zetterman, Rowen K.; Risser, Richard; Rossi, Stephen S.; Hofmann, Alan F.

2014-01-01

Bile acid composition in fasting duodenal bile was assessed at entry and at 2 years in patients with primary biliary cirrhosis (PBC) enrolled in a randomized, double-blind, placebo-controlled trial of ursodeoxycholic acid (UDCA) (10–12 mg/kg/d) taken as a single bedtime dose. Specimens were analyzed by a high-pressure liquid chromatography method that had been validated against gas chromatography. Percent composition in bile (mean ± SD) for 98 patients at entry for cholic (CA), chenodeoxycholic (CDCA), deoxycholic (DCA), lithocholic (LCA), and ursodeoxycholic (UDCA) acids, respectively, were 57.4 ± 18.6, 31.5 ± 15.5, 8.0 ± 9.3, 0.3 ± 1.0, and 0.6 ± 0.9. Values for CA were increased, whereas those for CDCA, DCA, LCA, and UDCA were decreased when compared with values in normal persons. Bile acid composition of the major bile acids did not change after 2 years on placebo medication. By contrast, in patients receiving UDCA for 2 years, bile became enriched with UDCA on average to 40.1%, and significant decreases were noted for CA (to 32.2%) and CDCA (to 19.5%). No change in percent composition was observed for DCA and LCA. Percent composition at entry and changes in composition after 2 years on UDCA were similar in patients with varying severity of PBC. In patients whose bile was not enriched in UDCA (entry and placebo-treated specimens), CA, CDCA, DCA, and the small amount of UDCA found in some of these specimens were conjugated to a greater extent with glycine (52%–64%) than with taurine (36%–48%). Treatment with UDCA caused the proportion of all endogenous bile acids conjugated with glycine to increase to 69% to 78%, while the proportion conjugated with taurine (22%–31%) fell (P < .05). Administered UDCA was also conjugated predominantly with glycine (87%). PMID:10347103

Boldine enhances bile production in rats via osmotic and Farnesoid X receptor dependent mechanisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cermanova, Jolana; Kadova, Zuzana; Deparment of Pharmacology and Toxicology, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove

Boldine, the major alkaloid from the Chilean Boldo tree, is used in traditional medicine to support bile production, but evidence to support this function is controversial. We analyzed the choleretic potential of boldine, including its molecular background. The acute- and long-term effects of boldine were evaluated in rats either during intravenous infusion or after 28-day oral treatment. Infusion of boldine instantly increased the bile flow 1.4-fold in healthy rats as well as in animals with Mrp2 deficiency or ethinylestradiol induced cholestasis. This effect was not associated with a corresponding increase in bile acid or glutathione biliary excretion, indicating that themore » effect is not related to stimulation of either bile acid dependent or independent mechanisms of bile formation and points to the osmotic activity of boldine itself. We subsequently analyzed bile production under conditions of changing biliary excretion of boldine after bolus intravenous administration and found strong correlations between both parameters. HPLC analysis showed that bile concentrations of boldine above 10 μM were required for induction of choleresis. Importantly, long-term pretreatment, when the bile collection study was performed 24-h after the last administration of boldine, also accelerated bile formation despite undetectable levels of the compound in bile. The effect paralleled upregulation of the Bsep transporter and increased biliary clearance of its substrates, bile acids. We consequently confirmed the ability of boldine to stimulate the Bsep transcriptional regulator, FXR receptor. In conclusion, our study clarified the mechanisms and circumstances surrounding the choleretic activity of boldine. - Highlights: • Boldine may increase bile production by direct as well as indirect mechanisms. • Biliary concentrations of boldine above 10 μM directly stimulate bile production. • Long-term oral boldine administration increases bile acid (BA) biliary secretion. • Boldine induces Bsep-mediated transport of BA by FXR receptor stimulation.« less

Rapid and accurate reversed-phase high-performance liquid chromatographic determination of conjugated bile acids in human bile for routine clinical applications. Therapeutic control during gallstone dissolution therapy.

PubMed

Swobodnik, W; Klüppelberg, U; Wechsler, J G; Volz, M; Normandin, G; Ditschuneit, H

1985-05-03

This paper introduces a new method to detect the taurine and glycine conjugates of five different bile acids (cholic acid, deoxycholic acid, chenodeoxycholic acid, ursodeoxycholic acid and lithocholic acid) in human bile. Advantages of this method are sufficient separation of compounds within a short period of time and a high rate of reproducibility. Using a mobile phase gradient of acetonitrile and water, modified with tetrabutylammonium hydrogen sulphate (0.0075 mol/l), we were able to maximize the differentiation between ursodeoxycholic acid and lithocholic acid, which is of primary interest during conservative gallstone dissolution therapy. Use of this gradient reduced analysis time to less than 0.5 h. Recovery rates for this modified method ranged from 94% to 100%, and reproducibility was 98%, sufficient for routine clinical applications.

cGMP stimulates bile acid-independent bile formation and biliary bicarbonate excretion.

PubMed

Myers, N C; Grune, S; Jameson, H L; Sawkat-Anwer, M

1996-03-01

The effect of guanosine 3',5'-cyclic monophosphate (cGMP) on hepatic bile formation was studied in isolated perfused rat livers and rat hepatocytes. Studies in isolated perfused rat livers showed that infusion of 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP, 3 micromol/min or 100 microM) 1) increased bile flow without affecting biliary excretion of simultaneously infused taurocholate, 2) increased biliary concentration and excretion of HCO3(-) but did not affect biliary excretion of glutathione, and 3) increased net perfusate H+ efflux without affecting hepatic O2 uptake. Studies in isolated rat hepatocytes showed that 1) 8-BrcGMP increased intracellular pH in the presence (but not in the absence) of extracellular HCO-3, and effect inhibited by 4,4' -diisothiocyanostilbene-2,2'-disulfonic acid and Na+ replacement, 2) 8-BrcGMP did not affect taurocholate uptake and intracellular [Ca2+], and 3) bile acids, like ursodeoxycholate and cholate, did not increase cellular cGMP. Taken together, these results indicate that cGMP stimulates bile acid-independent bile formation, in part by stimulating biliary HCO3- excretion. cGMP may increase HCO3- excretion by stimulating sinusoidal Na+ - HCO3- cotransport, but not Na+/H+ exchange. cGMP, unlike adenosine 3',5'-cyclic monophosphate, may not regulate hepatic taurocholate transport, and bile acid-induced HCO3- rich choleresis may not be mediated via cGMP.

Effects of bile acids on human airway epithelial cells: implications for aerodigestive diseases.

PubMed

Aldhahrani, Adil; Verdon, Bernard; Ward, Chris; Pearson, Jeffery

2017-01-01

Gastro-oesophageal reflux and aspiration have been associated with chronic and end-stage lung disease and with allograft injury following lung transplantation. This raises the possibility that bile acids may cause lung injury by damaging airway epithelium. The aim of this study was to investigate the effect of bile acid challenge using the immortalised human bronchial epithelial cell line (BEAS-2B). The immortalised human bronchial epithelial cell line (BEAS-2B) was cultured. A 48-h challenge evaluated the effect of individual primary and secondary bile acids. Post-challenge concentrations of interleukin (IL)-8, IL-6 and granulocyte-macrophage colony-stimulating factor were measured using commercial ELISA kits. The viability of the BEAS-2B cells was measured using CellTiter-Blue and MTT assays. Lithocholic acid, deoxycholic acid, chenodeoxycholic acid and cholic acid were successfully used to stimulate cultured BEAS-2B cells at different concentrations. A concentration of lithocholic acid above 10 μmol·L -1 causes cell death, whereas deoxycholic acid, chenodeoxycholic acid and cholic acid above 30 μmol·L -1 was required for cell death. Challenge with bile acids at physiological levels also led to a significant increase in the release of IL-8 and IL6 from BEAS-2B. Aspiration of bile acids could potentially cause cell damage, cell death and inflammation in vivo . This is relevant to an integrated gastrointestinal and lung physiological paradigm of chronic lung disease, where reflux and aspiration are described in both chronic lung diseases and allograft injury.

Biochemical basis for activation of virulence genes by bile salts in Vibrio parahaemolyticus.

PubMed

Rivera-Cancel, Giomar; Orth, Kim

2017-07-04

Bile salts act as a stressor to bacteria that transit the intestinal tract. Enteric pathogens have hijacked bile as an intestinal signal to regulate virulence factors. We recently demonstrated that Vibrio parahemolyticus senses bile salts via a heterodimeric receptor formed by the periplasmic domains of inner-membrane proteins VtrA and VtrC. Crystal structures of the periplasmic complex reveal that VtrA and VtrC form a β-barrel that binds bile salts in its hydrophobic interior to activate the VtrA cytoplasmic DNA-binding domain. Proteins with the same domain arrangement as VtrA and VtrC are widespread in Vibrio and related bacteria, where they are involved in regulating virulence and other unknown functions. Here we discuss our findings and review current knowledge on VtrA and VtrC homologs. We propose that signaling by these membrane-bound transcription factors can be advantageous for the regulation of membrane and secretory proteins.

[Combined effect of benzylpenicillin, furagin and bile acids on staphylococci].

PubMed

Sytnik, I A; Tkachuk, N I

1982-11-01

The results of the study of the effect of benzylpenicillin or furagin in combination with bile acids, such as cholic, glycocholic and desoxycholic on the collection cultures of staphylococci are presented. The study showed that the subbacteriostatic doses of the bile acids increased the bacteriostatic and bactericidal effects of benzylpenicillin and furagin by tens and hundreds times. The highest potentiation effect was attained with the use of the furagin combination and desoxycholic acid.

Molecular Properties of Guar Gum and Pectin Modify Cecal Bile Acids, Microbiota, and Plasma Lipopolysaccharide-Binding Protein in Rats

PubMed Central

Ghaffarzadegan, Tannaz; Marungruang, Nittaya; Fåk, Frida; Nyman, Margareta

2016-01-01

Bile acids (BAs) act as signaling molecules in various physiological processes, and are related to colonic microbiota composition as well as to different types of dietary fat and fiber. This study investigated whether guar gum and pectin—two fibers with distinct functional characteristics—affect BA profiles, microbiota composition, and gut metabolites in rats. Low- (LM) or high-methoxylated (HM) pectin, and low-, medium-, or high-molecular-weight (MW) guar gum were administered to rats that were fed either low- or high-fat diets. Cecal BAs, short-chain fatty acids (SCFA) and microbiota composition, and plasma lipopolysaccharide-binding protein (LBP) levels were analyzed, by using novel methodologies based on gas chromatography (BAs and SCFAs) and 16S rRNA gene sequencing on the Illumina MiSeq platform. Strong correlations were observed between cecal BA and SCFA levels, microbiota composition, and portal plasma LBP levels in rats on a high-fat diet. Notably, guar gum consumption with medium-MW increased the cecal amounts of cholic-, chenodeoxycholic-, and ursodeoxycholic acids as well as α-, β-, and ω-muricholic acids to a greater extent than other types of guar gum or the fiber-free control diet. In contrast, the amounts of cecal deoxycholic- and hyodeoxycholic acid were reduced with all types of guar gum independent of chain length. Differences in BA composition between pectin groups were less obvious, but cecal levels of α- and ω-muricholic acids were higher in rats fed LM as compared to HM pectin or the control diet. The inflammatory marker LBP was downregulated in rats fed medium-MW guar gum and HM pectin; these two fibers decreased the cecal abundance of Oscillospira and an unclassified genus in Ruminococcaceae, and increased that of an unclassified family in RF32. These results indicate that the molecular properties of guar gum and pectin are important for their ability to modulate cecal BA formation, gut microbiota composition, and high-fat diet induced inflammation. PMID:27315087

Transport of bile acids in multidrug-resistance-protein 3-overexpressing cells co-transfected with the ileal Na+-dependent bile-acid transporter.

PubMed Central

Zelcer, Noam; Saeki, Tohru; Bot, Ilse; Kuil, Annemieke; Borst, Piet

2003-01-01

Many of the transporters involved in the transport of bile acids in the enterohepatic circulation have been characterized. The basolateral bile-acid transporter of ileocytes and cholangiocytes remains an exception. It has been suggested that rat multidrug resistance protein 3 (Mrp3) fulfills this function. Here we analyse bile-salt transport by human MRP3. Membrane vesicles from insect ( Spodoptera frugiperda ) cells expressing MRP3 show time-dependent uptake of glycocholate and taurocholate. Furthermore, sulphated bile salts were high-affinity competitive inhibitors of etoposide glucuronide transport by MRP3 (IC50 approximately 10 microM). Taurochenodeoxycholate, taurocholate and glycocholate inhibited transport at higher concentrations (IC50 approximately 100, 250 and 500 microM respectively). We used mouse fibroblast-like cell lines derived from mice with disrupted Mdr1a, Mdr1b and Mrp1 genes to generate transfectants that express the murine apical Na+-dependent bile-salt transporter (Asbt) and MRP3. Uptake of glycocholate by these cells is Na+-dependent, with a K(m) and V(max) of 29+/-7 microM and 660 +/- 63 pmol/min per mg of protein respectively and is inhibited by several organic-aniontransport inhibitors. Expression of MRP3 in these cells limits the accumulation of glycocholate and increases the efflux from cells preloaded with taurocholate or glycocholate. In conclusion, we find that MRP3 transports both taurocholate and glycocholate, albeit with low affinity, in contrast with the high-affinity transport by rat Mrp3. Our results suggest that MRP3 is unlikely to be the principal basolateral bile-acid transporter of ileocytes and cholangiocytes, but that it may have a role in the removal of bile acids from the liver in cholestasis. PMID:12220224

Ursodeoxycholic acid lowers bile lithogenicity by regulating SCP2 expression in rabbit cholesterol gallstone models

PubMed Central

Cui, Yunfeng; Li, Zhonglian; Zhao, Erpeng; Zhang, Ju; Cui, Naiqiang

2012-01-01

Aims: We designed this study to get insight into the disorder of lipid metabolism during cholesterol gallstone formation and evaluate the effect of ursodeoxycholic acid on the improvement of bile lithogenicity and on expression of lipid related genes. Methods: Rabbit cholesterol gallstone models were induced by high cholesterol diet. Bile, blood and liver tissues were obtained from rabbits after 0, 1, 2, 3, 4 and 5 weeks. Bile and blood lipids were measured enzymatically. 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), cytochrome P450, family 7, subfamily A, polypeptide 1 (CYP7A1) and sterol carrier protein 2 (SCP2) mRNA expressions were detected by using quantitative real-time RT-PCR. Cholesterol saturation index (CSI) was calculated by using Carey table to represent the bile lithogenicity. Results: Rates of gallstone formation of the 4 and 5 week treatment groups were 100 %, but that of the ursodeoxycholic acid treatment group was only 33.3 %. Expression of HMGCR and SCP2 mRNA in the 4 week group was upregulated and that of CYP7A1 mRNA decreased as compared with the 0 week group. Ursodeoxycholic acid could significantly extend nucleation time of bile and lower CSI. Ursodeoxycholic acid could reduce the expression of SCP2, but couldn't influence expression of HMGCR and CYP7A1. Conclusions: Abnormal expression of HMGCR, CYP7A1 and SCP2 might lead to high lithogenicity of bile. Ursodeoxycholic acid could improve bile lipids and lower bile lithogenicity, thereby reducing the incidence of gallstones. So it might be a good preventive drug for cholesterol gallstones. PMID:27847447

Opposing effects of bile acids deoxycholic acid and ursodeoxycholic acid on signal transduction pathways in oesophageal cancer cells.

PubMed

Abdel-Latif, Mohamed M; Inoue, Hiroyasu; Reynolds, John V

2016-09-01

Ursodeoxycholic acid (UDCA) was reported to reduce bile acid toxicity, but the mechanisms underlying its cytoprotective effects are not fully understood. The aim of the present study was to examine the effects of UDCA on the modulation of deoxycholic acid (DCA)-induced signal transduction in oesophageal cancer cells. Nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) activity was assessed using a gel shift assay. NF-κB activation and translocation was performed using an ELISA-based assay and immunofluorescence analysis. COX-2 expression was analysed by western blotting and COX-2 promoter activity was assessed by luciferase assay. DCA induced NF-κB and AP-1 DNA-binding activities in SKGT-4 and OE33 cells. UDCA pretreatment inhibited DCA-induced NF-κB and AP-1 activation and NF-κB translocation. This inhibitory effect was coupled with a blockade of IκB-α degradation and inhibition of phosphorylation of IKK-α/β and ERK1/2. Moreover, UDCA pretreatment inhibited COX-2 upregulation. Using transient transfection of the COX-2 promoter, UDCA pretreatment abrogated DCA-induced COX-2 promoter activation. In addition, UDCA protected oesophageal cells from the apoptotic effects of deoxycholate. Our findings indicate that UDCA inhibits DCA-induced signalling pathways in oesophageal cancer cells. These data indicate a possible mechanistic role for the chemopreventive actions of UDCA in oesophageal carcinogenesis.

Multiple copies of a bile acid-inducible gene in Eubacterium sp. strain VPI 12708.

PubMed Central

Gopal-Srivastava, R; Mallonee, D H; White, W B; Hylemon, P B

1990-01-01

Eubacterium sp. strain VPI 12708 is an anaerobic intestinal bacterium which possesses inducible bile acid 7-dehydroxylation activity. Several new polypeptides are produced in this strain following induction with cholic acid. Genes coding for two copies of a bile acid-inducible 27,000-dalton polypeptide (baiA1 and baiA2) have been previously cloned and sequenced. We now report on a gene coding for a third copy of this 27,000-dalton polypeptide (baiA3). The baiA3 gene has been cloned in lambda DASH on an 11.2-kilobase DNA fragment from a partial Sau3A digest of the Eubacterium DNA. DNA sequence analysis of the baiA3 gene revealed 100% homology with the baiA1 gene within the coding region of the 27,000-dalton polypeptides. The baiA2 gene shares 81% sequence identity with the other two genes at the nucleotide level. The flanking nucleotide sequences associated with the baiA1 and baiA3 genes are identical for 930 bases in the 5' direction from the initiation codon and for at least 325 bases in the 3' direction from the stop codon, including the putative promoter regions for the genes. An additional open reading frame (occupying from 621 to 648 bases, depending on the correct start codon) was found in the identical 5' regions associated with the baiA1 and baiA3 clones. The 5' sequence 930 bases upstream from the baiA1 and baiA3 genes was totally divergent. The baiA2 gene, which is part of a large bile acid-inducible operon, showed no homology with the other two genes either in the 5' or 3' direction from the polypeptide coding region, except for a 15-base-pair presumed ribosome-binding site in the 5' region. These studies strongly suggest that a gene duplication (baiA1 and baiA3) has occurred and is stably maintained in this bacterium. Images PMID:2376563

Bile salt kinetics in cystic fibrosis: influence of pancreatic enzyme replacement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watkins, J.B.; Tercyak, A.M.; Szczepanik, P.

1977-01-01

Bile acid kinetics was investigated by stable isotope dilution technique in 6 children (ages 3/sup 1///sub 2/ months to 4/sup 1///sub 2/ years) with previously untreated cystic fibrosis. All of the patients had clinical and laboratory evidence of malabsorption, normal intestinal mucosal function, as judged by glucose absorption, intestinal histology, disaccharidase levels, and normally functioning gallbladders. The children were maintained on a constant diet throughout the study period; fat intake averaged 4.2 g per kg per day. Before administration of pancreatic enzyme replacement, fat excretion equalled 50 +- 4% (mean +- SE) of intake and was reduced to 20 +-more » 1.0% of intake after therapy. Total bile acid pool size nearly doubled during enzyme replacement from 379 +- 32 ..mu..moles per kg to 620 +- 36 ..mu..moles per kg with secondary bile acids comprising 57% of the total pool before therapy and 40% after therapy. The data indicate that both primary and secondary bile acids are conserved within the enterohepatic circulation during enzyme therapy, and that the mechanism for the regulation of hepatic bile acid synthesis is intact in cystic fibrosis. However, the demonstration that large amounts of bile acid continue to be excreted during therapy suggests that interruption of the enterohepatic circulation continues and that deficiencies of the intraluminal phase may persist during enzyme therapy in this disease.« less

Supramolecular Complexes Formed in Systems Bile Salt-Bilirubin-Silica

NASA Astrophysics Data System (ADS)

Vlasova, N. N.; Severinovskaya, O. V.; Golovkova, L. P.

The formation of supramolecular complexes between bilirubin and primary micelles of bile salts has been studied. The association constants of bile salts and binding of bilirubin with these associates have been determined. The adsorption of bilirubin and bile salts from individual and mixed aqueous solutions onto hydrophobic silica surfaces has been investigated. The interaction of bilirubin with primary bile salt micelles and the strong retention in mixed micelles, which are supramolecular complexes, result in the adsorption of bilirubin in free state only.

Indirect electrochemical detection for total bile acids in human serum.

PubMed

Zhang, Xiaoqing; Zhu, Mingsong; Xu, Biao; Cui, Yue; Tian, Gang; Shi, Zhenghu; Ding, Min

2016-11-15

Bile acids level in serum is a useful index for screening and diagnosis of hepatobiliary diseases. As bile acids concentration is closely related to the degree of hepatobiliary diseases, detecting it is a vital factor to understand the stage of the diseases. The prevalent determination for bile acids is the enzymatic cycling method which has low sensitivity while reagent-consuming. It is desirable to develop a new method with lower cost and higher sensitivity. An indirect electrochemical detection (IED) for bile acids in human serum was established using the screen printed carbon electrode (SPCE). Since bile acids do not show electrochemical signals, they were converted to 3-ketosteroids by 3-α-hydroxysteroid dehydrogenase (3α-HSD) in the presence of nicotinamide adenine dinucleotide (NAD(+)), which was reduced to NADH. NADH could then be oxidized on the surface of SPCE, generating a signal that was used to calculate the total bile acids (TBA) concentration. A good linear calibration for TBA was obtained at the concentration range from 5.00μM to 400μM in human serum. Both the precisions and recoveries were sufficient to be used in a clinical setting. The TBA concentrations in 35 human serum samples by our IED method didn't show significant difference with the result by enzymatic cycling method, using the paired t-test. Moreover, our IED method is reagent-saving, sensitive and cost-effective. Copyright © 2016. Published by Elsevier B.V.

The role of the gallbladder in humans.

PubMed

Turumin, J L; Shanturov, V A; Turumina, H E

2013-01-01

The basic function of the gallbladder in humans is one of protection. The accumulation of the primary bile acids (cholic acid and chenodeoxycholic acid) in the gallbladder reduces the formation of the secondary bile acids (deoxycholic acid and lithocholic acid), thus diminishing their concentration in the so-called gallbladder-independent enterohepatic circulation and protecting the liver, the stomach mucosa, the gallbladder, and the colon from their toxic hydrophobic effects. The presence or absence of the gallbladder in mammals is a determining factor in the synthesis of hydrophobic or hydrophilic bile acids. Because the gallbladder contracts 5-20 min after food is in the stomach and the "gastric chyme" moves from the stomach to the duodenum 1-3 h later, the function of the gallbladder bile in digestion may be insignificant. The aim of this article was to provide a detailed review of the role of the gallbladder and the mechanisms related to bile formation in humans. Copyright © 2012 Asociación Mexicana de Gastroenterología. Published by Masson Doyma México S.A. All rights reserved.

Rapid analysis of bile acids in different biological matrices using LC-ESI-MS/MS for the investigation of bile acid transformation by mammalian gut bacteria.

PubMed

Wegner, Katrin; Just, Sarah; Gau, Laura; Mueller, Henrike; Gérard, Philippe; Lepage, Patricia; Clavel, Thomas; Rohn, Sascha

2017-02-01

Bile acids are important signaling molecules that regulate cholesterol, glucose, and energy homoeostasis and have thus been implicated in the development of metabolic disorders. Their bioavailability is strongly modulated by the gut microbiota, which contributes to generation of complex individual-specific bile acid profiles. Hence, it is important to have accurate methods at hand for precise measurement of these important metabolites. Here, a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous identification and quantitation of primary and secondary bile acids as well as their taurine and glycine conjugates was developed and validated. Applicability of the method was demonstrated for mammalian tissues, biofluids, and cell culture media. The analytical approach mainly consists of a simple and rapid liquid-liquid extraction procedure in presence of deuterium-labeled internal standards. Baseline separation of all isobaric bile acid species was achieved and a linear correlation over a broad concentration range was observed. The method showed acceptable accuracy and precision on intra-day (1.42-11.07 %) and inter-day (2.11-12.71 %) analyses and achieved good recovery rates for representative analytes (83.7-107.1 %). As a proof of concept, the analytical method was applied to mouse tissues and biofluids, but especially to samples from in vitro fermentations with gut bacteria of the family Coriobacteriaceae. The developed method revealed that the species Eggerthella lenta and Collinsella aerofaciens possess bile salt hydrolase activity, and for the first time that the species Enterorhabdus mucosicola is able to deconjugate and dehydrogenate primary bile acids in vitro.

EXOCRINE FUNCTION OF THE LIVER IN RATS WITH EXPOSURE TO CОRVITIN.

PubMed

Vovkun, T V; Yanchuk, P I; Shtanova, L Y; Vesеlskyу, S P; Shalamaу, A S

In acute experiments on rats with cannulated bile duct we studied the effect of Corvitin, water-soluble analogue of quercetin, on secretion of bile. Intraportal administration of the test compound at doses of 2,5; 5 and 10 mg/kg resulted in a significant increase in the volume of secreted bile by 20,9, 31,2 and 20,4%, respectively, as compared with the control. Using the method of thin layer chromatography it was established the mild stimulating effect of Corvitin on the processes of bile acids conjugation with taurine and glycine, especially when administered at a dose of 5 mg/kg. This flavonoid did not affect the concentration of glycocholic acid, however increased the content of glycochenodeoxycholic and glycodeoxycholic acids in the mixture between 15 to 35,1%. Regarding free bile acids, the concentration of cholic acid, chenodeoxycholic and deoxycholic acids in the mixture was increased significantly relative to control only after Corvitin application at dose 10 mg/ kg. In the first case – from 17,9 to 29,8%, in the second – from 25 to 65,4%. At the dose of 5 mg/kg, Corvitin significantly increased the ratio of bile cholates conjugation (maximum by 23,2%), whereas 10 mg/kg of the drug decreased this index by 27,0%. After administration of Corvitin, the hydroxylation ratio in all experimental groups differed little from the control: at the dose of 5 and 10 mg/kg this parameter decreased by 14%. Thus, Corvitin modulates exocrine function of the liver, causing an increase in bile secretion and concentration of different cholates, dose-dependently increasing or decreasing the effectiveness of multienzyme systems providing processes of bile acids conjugation in rats.

Different effects of ursodeoxycholic acid on intrahepatic cholestasis in acute and recovery stages induced by alpha-naphthylisothiocyanate in mice.

PubMed

Zhang, Linlin; Su, Huizong; Li, Yue; Fan, Yujuan; Wang, Qian; Jiang, Jian; Hu, Yiyang; Chen, Gaofeng; Tan, Bo; Qiu, Furong

2018-03-01

The aim of this study was to determine the effect of ursodeoxycholic acid (UDCA) on the alpha-naphthylisothiocyanate (ANIT)-induced acute and recovery stage of cholestasis model mice. In the acute stage of model mice, pretreatment with UDCA (25, 50, and 100 mg·kg -1 , ig) for 12 days prior to ANIT administration (50 mg·kg -1 , ig) resulted in the dramatic increase in serum biochemistry, with aggrevation of bile infarcts and hepatocyte necrosis. The elevation of beta-muricholic acid (β-MCA), cholic acid (CA), and taurocholic acid (TCA) in serum and liver, and reduction of these bile acids (BAs) in bile was observed. In contrast, in the recovery stage of model mice, treatment with UDCA (25, 50, and 100 mg·kg -1 , ig) for 7 days after ANIT administration (50 mg·kg -1 , ig) resulted in the significant decrease in levels of serum alanine aminotransferase (ALT) and total bile acid (TBA). Liver injury was attenuated, and the levels of TBA, CA, TCA, and β-MCA in the liver were significantly decreased. Additionally, UDCA can upregulate expression of BSEP, but it cannot upregulate expression of AE2. UDCA, which induced BSEP to increase bile acid-dependent bile flow, aggravated cholestasis and liver injury when the bile duct was obstructed in the acute stage of injury in model mice. In contrast, UDCA alleviated cholestasis and liver injury induced by ANIT when the obstruction was improved in the recovery stage. Copyright © 2018. Published by Elsevier Inc.

Identification and characterization of a novel PPARα-regulated and 7α-hydroxyl bile acid-preferring cytosolic sulfotransferase mL-STL (Sult2a8)[S

PubMed Central

Feng, Lu; Yuen, Yee-Lok; Xu, Jian; Liu, Xing; Chan, Martin Yan-Chun; Wang, Kai; Fong, Wing-Ping; Cheung, Wing-Tai; Lee, Susanna Sau-Tuen

2017-01-01

PPARα has been known to play a pivotal role in orchestrating lipid, glucose, and amino acid metabolism via transcriptional regulation of its target gene expression during energy deprivation. Recent evidence has also suggested that PPARα is involved in bile acid metabolism, but how PPARα modulates the homeostasis of bile acids during fasting is still not clear. In a mechanistic study aiming to dissect the spectrum of PPARα target genes involved in metabolic response to fasting, we identified a novel mouse gene (herein named mL-STL for mouse liver-sulfotransferase-like) that shared extensive homology with the Sult2a subfamily of a superfamily of cytosolic sulfotransferases, implying its potential function in sulfonation. The mL-STL gene expressed predominantly in liver in fed state, but PPARα was required to sustain its expression during fasting, suggesting a critical role of PPARα in regulating the mL-STL-mediated sulfonation during fasting. Functional studies using recombinant His-tagged mL-STL protein revealed its narrow sulfonating activities toward 7α-hydroxyl primary bile acids, including cholic acid, chenodeoxycholic acid, and α-muricholic acid, and thus suggesting that mL-STL may be the major hepatic bile acid sulfonating enzyme in mice. Together, these studies identified a novel PPARα-dependent gene and uncovered a new role of PPARα as being an essential regulator in bile acid biotransformation via sulfonation during fasting. PMID:28442498

Bile

MedlinePlus

... the digestive tract. Bile contains: Mostly cholesterol Bile acids (also called bile salts) Bilirubin (a breakdown product or red blood cells) It also contains: Water Body salts (such as potassium and sodium) Copper and other metals

[Research of conjugated bile acids in gallbladder bile of patients with polypoid lesions of gallbladder].

PubMed

Ge, Chunlin; Sun, Tao; Meng, Jingjuan; Wang, Kun; Huang, Peng

2014-02-01

To investigate the difference in conjugated bile acids in the gallbladder bile between gallbladder cholesterol polyps and adenomatous polyps patients, and screen the differential diagnosis-markers for polypoid lesions of gallbladder (PLG). From January to June 2013, the 20 cholesterol polyps patients, 10 adenomatous polyps patients and 10 patients without gallbladder diseases were enrolled. High performance liquid chromatography assay with ultraviolet detection was used to test 8 conjugated bile acids in gallbladder bile. The 8 conjugated bile acids were completely analyzed in 10 minutes, and the assay was liner in the range 8-500 µg/ml. The correlation coeffients for linear regression was from 0.9996-0.9999 and the detection limits ranged from 3.90-7.81 µg/ml. The level of taurocholic acid (TCA) in adenomatous polyps group ((75 ± 51) µg/ml) was significantly lower than that in the cholesterol polyps ((228 ± 206) µg/ml, q = 3.120, P = 0.014) and control groups ((104 ± 40) µg/ml, q = 2.950, P = 0.027). The level of taurochenodeoxycholic acid (TCDCA) in cholesterol polyps group ((604 ± 444) µg/ml) was significantly higher than that in the adenomatous polyps ((310 ± 182) µg/ml, q = 2.560, P = 0.048) and control groups ((308 ± 21) µg/ml, q = 2.970, P = 0.023). The levels of TCA and TCDCA in the gallbladder biles in cholesterol polyps patients were higher than those in adenomatous polyps patients, which may be the differential diagnosis-markers for PLG.

Microbiome-mediated bile acid modification: Role in intestinal drug absorption and metabolism.

PubMed

Enright, Elaine F; Griffin, Brendan T; Gahan, Cormac G M; Joyce, Susan A

2018-04-13

Once regarded obscure and underappreciated, the gut microbiota (the microbial communities colonizing the gastrointestinal tract) is gaining recognition as an influencer of many aspects of human health. Also increasingly apparent is the breadth of interindividual variation in these co-evolved microbial-gut associations, presenting novel quests to explore implications for disease and therapeutic response. In this respect, the unearthing of the drug-metabolizing capacity of the microbiota has provided impetus for the integration of microbiological and pharmacological research. This review considers a potential mechanism, 'microbial bile acid metabolism', by which the intricate interplay between the host and gut bacteria may influence drug pharmacokinetics. Bile salts traditionally regarded as biological surfactants, synthesized by the host and biotransformed by gut bacteria, are now also recognized as signalling molecules that affect diverse physiological processes. Accumulating data indicate that bile salts are not equivalent with respect to their physicochemical properties, micellar solubilization capacities for poorly water-soluble drugs, crystallization inhibition tendencies nor potencies for bile acid receptor activation. Herein, the origin, physicochemical properties, physiological functions, plasticity and pharmaceutical significance of the human bile acid pool are discussed. Microbial dependant differences in the composition of the human bile acid pool, simulated intestinal media and commonly used preclinical species is highlighted to better understand in vivo performance predictiveness. While the precise impact of an altered gut microbiome, and consequently bile acid pool, in the biopharmaceutical setting remains largely elusive, the objective of this article is to aid knowledge acquisition through a detailed review of the literature. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cloning, sequencing, and expression of the gene coding for bile acid 7 alpha-hydroxysteroid dehydrogenase from Eubacterium sp. strain VPI 12708.

PubMed Central

Baron, S F; Franklund, C V; Hylemon, P B

1991-01-01

Southern blot analysis indicated that the gene encoding the constitutive, NADP-linked bile acid 7 alpha-hydroxysteroid dehydrogenase of Eubacterium sp. strain VPI 12708 was located on a 6.5-kb EcoRI fragment of the chromosomal DNA. This fragment was cloned into bacteriophage lambda gt11, and a 2.9-kb piece of this insert was subcloned into pUC19, yielding the recombinant plasmid pBH51. DNA sequence analysis of the 7 alpha-hydroxysteroid dehydrogenase gene in pBH51 revealed a 798-bp open reading frame, coding for a protein with a calculated molecular weight of 28,500. A putative promoter sequence and ribosome binding site were identified. The 7 alpha-hydroxysteroid dehydrogenase mRNA transcript in Eubacterium sp. strain VPI 12708 was about 0.94 kb in length, suggesting that it is monocistronic. An Escherichia coli DH5 alpha transformant harboring pBH51 had approximately 30-fold greater levels of 7 alpha-hydroxysteroid dehydrogenase mRNA, immunoreactive protein, and specific activity than Eubacterium sp. strain VPI 12708. The 7 alpha-hydroxysteroid dehydrogenase purified from the pBH51 transformant was similar in subunit molecular weight, specific activity, and kinetic properties to that from Eubacterium sp. strain VPI 12708, and it reached with antiserum raised against the authentic enzyme on Western immunoblots. Alignment of the amino acid sequence of the 7 alpha-hydroxysteroid dehydrogenase with those of 10 other pyridine nucleotide-linked alcohol/polyol dehydrogenases revealed six conserved amino acid residues in the N-terminal regions thought to function in coenzyme binding. Images PMID:1856160

Bile Salt Homeostasis in Normal and Bsep Gene Knockout Rats with Single and Repeated Doses of Troglitazone.

PubMed

Cheng, Yaofeng; Chen, Shenjue; Freeden, Chris; Chen, Weiqi; Zhang, Yueping; Abraham, Pamela; Nelson, David M; Humphreys, W Griffith; Gan, Jinping; Lai, Yurong

2017-09-01

The interference of bile acid secretion through bile salt export pump (BSEP) inhibition is one of the mechanisms for troglitazone (TGZ)-induced hepatotoxicity. Here, we investigated the impact of single or repeated oral doses of TGZ (200 mg/kg/day, 7 days) on bile acid homoeostasis in wild-type (WT) and Bsep knockout (KO) rats. Following oral doses, plasma exposures of TGZ were not different between WT and KO rats, and were similar on day 1 and day 7. However, plasma exposures of the major metabolite, troglitazone sulfate (TS), in KO rats were 7.6- and 9.3-fold lower than in WT on day 1 and day 7, respectively, due to increased TS biliary excretion. With Bsep KO, the mRNA levels of multidrug resistance-associated protein 2 (Mrp2), Mrp3, Mrp4, Mdr1, breast cancer resistance protein (Bcrp), sodium taurocholate cotransporting polypeptide, small heterodimer partner, and Sult2A1 were significantly altered in KO rats. Following seven daily TGZ treatments, Cyp7A1 was significantly increased in both WT and KO rats. In the vehicle groups, plasma exposures of individual bile acids demonstrated variable changes in KO rats as compared with WT. WT rats dosed with TGZ showed an increase of many bile acid species in plasma on day 1, suggesting the inhibition of Bsep. Conversely, these changes returned to base levels on day 7. In KO rats, alterations of most bile acids were observed after seven doses of TGZ. Collectively, bile acid homeostasis in rats was regulated through bile acid synthesis and transport in response to Bsep deficiency and TGZ inhibition. Additionally, our study is the first to demonstrate that repeated TGZ doses can upregulate Cyp7A1 in rats. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Synthesis and Evaluation of Vitamin D Receptor-Mediated Activities of Cholesterol and Vitamin D Metabolites

PubMed Central

Teske, Kelly A.; Bogart, Jonathan W.; Sanchez, Luis M.; Yu, Olivia B.; Preston, Joshua V.; Cook, James M.; Silvaggi, Nicholas R.; Bikle, Daniel D.; Arnold, Leggy A.

2016-01-01

A systematic study with phase 1 and phase 2 metabolites of cholesterol and vitamin D was conducted to determine whether their biological activity is mediated by the vitamin D receptor (VDR). The investigation necessitated the development of novel synthetic routes for lithocholic acid (LCA) glucuronides (Gluc). Biochemical and cell-based assays were used to demonstrate that hydroxylated LCA analogs were not able to bind VDR. This excludes VDR from mediating their biological and pharmacological activities. Among the synthesized LCA conjugates a novel VDR agonist was identified. LCA Gluc II increased the expression of CYP24A1 in DU145 cancer cells especially in the presence of the endogenous VDR ligand 1,25(OH)2D3. Furthermore, the methyl ester of LCA was identified as novel VDR antagonist. For the first time, we showed that calcitroic acid, the assumed inactive final metabolite of vitamin D, was able to activate VDR-mediated transcription to a higher magnitude than bile acid LCA. Due to a higher metabolic stability in comparison to vitamin D, a very low toxicity, and high concentration in bile and intestine, calcitroic acid is likely to be an important mediator of the protective vitamin D properties against colon cancer. PMID:26774929

Ursodeoxycholic acid treatment of vanishing bile duct syndromes

PubMed Central

Pusl, Thomas; Beuers, Ulrich

2006-01-01

Vanishing bile duct syndromes (VBDS) are characterized by progressive loss of small intrahepatic ducts caused by a variety of different diseases leading to chronic cholestasis, cirrhosis, and premature death from liver failure. The majority of adult patients with VBDS suffer from primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Ursodeoxycholic acid (UDCA), a hydrophilic dihydroxy bile acid, is the only drug currently approved for the treatment of patients with PBC, and anticholestatic effects have been reported for several other cholestatic syndromes. Several potential mechanisms of action of UDCA have been proposed including stimulation of hepatobiliary secretion, inhibition of apoptosis and protection of cholangiocytes against toxic effects of hydrophobic bile acids. PMID:16773706

Inhibition of ileal bile acid transporter: An emerging therapeutic strategy for chronic idiopathic constipation.

PubMed

Mosińska, Paula; Fichna, Jakub; Storr, Martin

2015-06-28

Chronic idiopathic constipation is a common disorder of the gastrointestinal tract that encompasses a wide profile of symptoms. Current treatment options for chronic idiopathic constipation are of limited value; therefore, a novel strategy is necessary with an increased effectiveness and safety. Recently, the inhibition of the ileal bile acid transporter has become a promising target for constipation-associated diseases. Enhanced delivery of bile acids into the colon achieves an accelerated colonic transit, increased stool frequency, and relief of constipation-related symptoms. This article provides insight into the mechanism of action of ileal bile acid transporter inhibitors and discusses their potential clinical use for pharmacotherapy of constipation in chronic idiopathic constipation.

Biliary Polyunsaturated Fatty Acids and Telocytes in Gallstone Disease

PubMed Central

Pasternak, Artur; Bugajska, Jolanta; Szura, Mirosław; Walocha, Jerzy A.; Matyja, Andrzej; Gajda, Mariusz; Sztefko, Krystyna; Gil, Krzysztof

2017-01-01

It has been reported that intake of ω-3 polyunsaturated fatty acids (PUFAs) reduces the risk of coronary heart disease. It also influences bile composition, decreasing biliary cholesterol saturation in the bile of patients with gallstones. In addition to bile composition disturbances, gallbladder hypomotility must be a cofactor in the pathogenesis of cholelithiasis, as it leads to the prolonged nucleation phase. Our current knowledge about gallbladder motility has been enhanced by the study of a population of newly described interstitial (stromal) cells—telocytes (TCs). The purpose of this study was to determine whether TC loss, reported by our team recently, might be related to bile lithogenicity, expressed as cholesterol saturation index or the difference in biliary PUFA profiles in patients who suffer from cholecystolithiasis and those not affected by this disease. We determined biliary lipid composition including the fatty acid composition of the phospholipid species in bile. Thus, we investigated whether differences in biliary fatty acid profiles (ω-3 PUFA and ω-6 PUFA) in gallbladder bile may influence its lithogenicity and the quantity of TCs within the gallbladder wall. We conclude that the altered PUFA concentrations in the gallbladder bile, with elevation of ω-6 PUFA, constitute important factors influencing TC density in the gallbladder wall, being one of the possible pathophysiological components for the gallstone disease development. This study established that altered bile composition in patients with cholelithiasis may influence TC quantity within the gallbladder muscle, and we concluded that reduction in TC number may be a consequence of the supersaturated bile toxicity, while some other bile components (ω-3 PUFA, glycocholic, and taurocholic acids) may exert protective effects on TC and thus possibly influence the mechanisms regulating gallbladder and extrahepatic bile duct motility. Thus, ω-3 PUFA may represent a possible option to prevent formation of cholesterol gallstones. PMID:27502173

Kinetic characterization of bile salt transport by human NTCP (SLC10A1).

PubMed

Jani, Márton; Beéry, Erzsébet; Heslop, Teresa; Tóth, Beáta; Jagota, Bhavana; Kis, Emese; Kevin Park, B; Krajcsi, Peter; Weaver, Richard J

2018-02-01

The transport of bile acids facilitated by NTCP is an important factor in establishing bile flow. In this study, we examine the kinetics associated with human NTCP-dependent transport of two quantitatively important bile acids comprising the human bile acid pool, chenodeoxycholic acid and glycine-chenodeoxycholate, and secondary bile salt, 3-sulfo-glycolithocholate of potential toxicological significance. The study employed human NTCP overexpressing Chinese Hamster Ovary cells and results compared with taurocholate, a prototypical bile salt commonly used in transporter studies. GCDC and 3S-GLC but not CDCA were transported by NTCP. The efficient uptake of GCDC, TCA and 3S-GLC by NTCP enabled the determination of kinetics. GCDC displayed a lower K M (0.569±0.318μM) than TCA (6.44±3.83μM) and 3S-GLC (3.78±1.17μM). The apparent CL int value for GCDC was 20-fold greater (153±53μl/mg protein/min) than the apparent CL int for TCA (6.92±4.72μl/mg protein/min) and apparent CL int for 3S-GLC (8.05±1.33μl/mg protein/min). These kinetic results provide important complementary data on the substrate selectivity and specificity of NTCP to transport bile acids. NTCP transports GCDC with greater efficiency than TCA and has the same efficacy for 3S-GLC and TCA. Copyright © 2017. Published by Elsevier Ltd.

Comparison of 75SeHCAT retention half-life and fecal content of individual bile acids in patients with chronic diarrheal disorders.

PubMed

Scheurlen, C; Kruis, W; Büll, U; Stellaard, F; Lang, P; Paumgartner, G

1986-01-01

Measurement of the retention of 23-75Se-25-homotaurocholic acid (SeHCAT) has been suggested as a new test for ileal function. We investigated 31 patients with chronic diarrhea, 10 with ileal Crohn's disease and 21 with diarrhea but without ileal disease. The whole-body retention half-life of 1 mu Ci SeHCAT was determined and compared to the fecal content of total and individual bile acids. Patients with ileal disease had increased primary fecal bile acids (chenodeoxycholic acid: mean 6.95 mg/g dry weight, range 3.15-10.6 mg/g; cholic acid: mean 18.15 mg/g, range 10.3-33.9 mg/g) and a short SeHCAT retention (mean 11.9 h, range 2-24 h), whereas patients with intact ileum had normal fecal bile acids and a SeHCAT retention of 85.9 h (range 28-216 h). SeHCAT retention half-life differentiated well between patients with ileal disease and patients with normal ileum, thus indicating the SeHCAT test as a valid investigation method for detection of primary bile acid malabsorption in patients with chronic diarrhea and ileal dysfunction.

Degree of fatty acyl chain unsaturation in biliary lecithin dictates cholesterol nucleation and crystal growth.

PubMed

Tazuma, S; Ochi, H; Teramen, K; Yamashita, Y; Horikawa, K; Miura, H; Hirano, N; Sasaki, M; Aihara, N; Hatsushika, S

1994-11-17

To clarify factors involved in the formation of cholesterol gallstones, we studied the relationship between the degree of fatty acyl chain unsaturation of biliary lecithin and bile metastability. We used supersaturated model bile solutions (molar taurocholate/lecithin/cholesterol ratio (73:19.5:7.5), total lipid concentration 9 g/dl) that contained equimolar egg yolk or soybean lecithins or a sn-1 palmitoyl, sn-2 linoleoyl phosphatidylcholine. Gel permeation chromatographic studies showed that the vesicular cholesterol distribution and dimension were inversely related to the degree of unsaturation of the lecithin species, estimated by reverse phase, high-performance liquid chromatography. Differential interference contrast microscopy and assay of cholesterol crystal growth showed that a higher degree of fatty acyl chain unsaturation of the lecithin species was associated with a faster nucleation time and rate of crystal growth. Our results suggest that vesicular lecithins containing more unsaturated fatty acyl chains bind less tightly to cholesterol than lecithins containing predominantly saturated fatty acids, and that the biliary lecithin species dictates, in part, the nucleation and growth of cholesterol crystals in bile.

Xenobiotic, Bile Acid, and Cholesterol Transporters: Function and Regulation

PubMed Central

Aleksunes, Lauren M.

2010-01-01

Transporters influence the disposition of chemicals within the body by participating in absorption, distribution, and elimination. Transporters of the solute carrier family (SLC) comprise a variety of proteins, including organic cation transporters (OCT) 1 to 3, organic cation/carnitine transporters (OCTN) 1 to 3, organic anion transporters (OAT) 1 to 7, various organic anion transporting polypeptide isoforms, sodium taurocholate cotransporting polypeptide, apical sodium-dependent bile acid transporter, peptide transporters (PEPT) 1 and 2, concentrative nucleoside transporters (CNT) 1 to 3, equilibrative nucleoside transporter (ENT) 1 to 3, and multidrug and toxin extrusion transporters (MATE) 1 and 2, which mediate the uptake (except MATEs) of organic anions and cations as well as peptides and nucleosides. Efflux transporters of the ATP-binding cassette superfamily, such as ATP-binding cassette transporter A1 (ABCA1), multidrug resistance proteins (MDR) 1 and 2, bile salt export pump, multidrug resistance-associated proteins (MRP) 1 to 9, breast cancer resistance protein, and ATP-binding cassette subfamily G members 5 and 8, are responsible for the unidirectional export of endogenous and exogenous substances. Other efflux transporters [ATPase copper-transporting β polypeptide (ATP7B) and ATPase class I type 8B member 1 (ATP8B1) as well as organic solute transporters (OST) α and β] also play major roles in the transport of some endogenous chemicals across biological membranes. This review article provides a comprehensive overview of these transporters (both rodent and human) with regard to tissue distribution, subcellular localization, and substrate preferences. Because uptake and efflux transporters are expressed in multiple cell types, the roles of transporters in a variety of tissues, including the liver, kidneys, intestine, brain, heart, placenta, mammary glands, immune cells, and testes are discussed. Attention is also placed upon a variety of regulatory factors that influence transporter expression and function, including transcriptional activation and post-translational modifications as well as subcellular trafficking. Sex differences, ontogeny, and pharmacological and toxicological regulation of transporters are also addressed. Transporters are important transmembrane proteins that mediate the cellular entry and exit of a wide range of substrates throughout the body and thereby play important roles in human physiology, pharmacology, pathology, and toxicology. PMID:20103563

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nasmyth, D.G.; Johnston, D.; Williams, N.S.

Bile acid absorption was investigated using /sup 75/Se Taurohomocholate (SeHCAT) in controls and patients who had undergone total colectomy with either conventional ileostomy or pouch-anal anastomosis for ulcerative colitis or adenomatous polyposis. Whole-body retention of SeHCAT after 168 hours was greater in the controls than the patients who had undergone colectomy (P less than .05). Retention of SeHCAT did not differ significantly between patients with an ileostomy and patients with pouch-anal anastomosis, but patients with an ileostomy and ileal resection of more than 20 cm retained less SeHCAT than patients with a pouch-anal anastomosis (P less than .01). Analysis ofmore » fecal bile acids from ileostomies and pouches showed that bacterial metabolism of primary conjugated bile acids was greater in patients with a pouch. It was concluded that bile acid absorption was not significantly impaired by construction of a pouch compared with conventional ileostomy, but bacterial metabolism of bile acids was greater in the pouches.« less

A new insight into the physiological role of bile salt hydrolase among intestinal bacteria from the genus Bifidobacterium.

PubMed

Jarocki, Piotr; Podleśny, Marcin; Glibowski, Paweł; Targoński, Zdzisław

2014-01-01

This study analyzes the occurrence of bile salt hydrolase in fourteen strains belonging to the genus Bifidobacterium. Deconjugation activity was detected using a plate test, two-step enzymatic reaction and activity staining on a native polyacrylamide gel. Subsequently, bile salt hydrolases from B. pseudocatenulatum and B. longum subsp. suis were purified using a two-step chromatographic procedure. Biochemical characterization of the bile salt hydrolases showed that the purified enzymes hydrolyzed all of the six major human bile salts under the pH and temperature conditions commonly found in the human gastrointestinal tract. Next, the dynamic rheometry was applied to monitor the gelation process of deoxycholic acid under different conditions. The results showed that bile acids displayed aqueous media gelating properties. Finally, gel-forming abilities of bifidobacteria exhibiting bile salt hydrolase activity were analyzed. Our investigations have demonstrated that the release of deconjugated bile acids led to the gelation phenomenon of the enzymatic reaction solution containing purified BSH. The presented results suggest that bile salt hydrolase activity commonly found among intestinal microbiota increases hydrogel-forming abilities of certain bile salts. To our knowledge, this is the first report showing that bile salt hydrolase activity among Bifidobacterium is directly connected with the gelation process of bile salts. In our opinion, if such a phenomenon occurs in physiological conditions of human gut, it may improve bacterial ability to colonize the gastrointestinal tract and their survival in this specific ecological niche.

Bile acid changes after high-dose ursodeoxycholic acid treatment in primary sclerosing cholangitis: relation to disease progression

PubMed Central

Sinakos, Emmanouil; Marschall, Hanns-Ulrich; Kowdley, Kris V.; Befeler, Alex; Keach, Jill; Lindor, Keith

2010-01-01

High-dose (28-30mg/kg/day) ursodeoxycholic acid (UDCA) treatment improves serum liver tests in patients with primary sclerosing cholangitis (PSC) but does not improve survival and is associated with increased rates of serious adverse events. The mechanism for the latter undesired effect remains unclear. High-dose UDCA could result in the production of hepatotoxic bile acids, such as lithocholic acid (LCA), due to limited small bowel absorption of UDCA and conversion of UDCA by bacteria in the colon. We determined the serum bile acid composition in 56 patients with PSC previously enrolled in a randomized, double-blind controlled trial of high dose UDCA versus placebo. Samples for analysis were obtained at baseline and at the end of treatment. The mean changes in UDCA (16.86 vs 0.05 μmol/L) and total bile acid (17.21 vs −0.55 μmol/L) levels were significantly higher in the UDCA group (n=29) compared to placebo (n=27) when pretreatment levels were compared (p<0.0001). LCA was also markedly increased (0.22 vs 0.01 μmol/L) in the UDCA group compared to placebo (p=0.001). No significant changes were detected for cholic acid (CA), deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA). Patients (n=9) in the UDCA group who reached clinical endpoints of disease progression (development of cirrhosis, varices, liver transplantation or death) tend to have greater increase in their post-treatment total bile acid levels (34.99 vs 9.21 μmol/L) (p<0.08) compared to those who did not. Conclusion High-dose UDCA treatment in PSC patients results in marked UDCA enrichment and significant expansion of the total serum bile acid pool including lithocholic acid. PMID:20564380

Very Long O-antigen Chains Enhance Fitness during Salmonella-induced Colitis by Increasing Bile Resistance

PubMed Central

Crawford, Robert W.; Keestra, A. Marijke; Winter, Sebastian E.; Xavier, Mariana N.; Tsolis, Renée M.; Tolstikov, Vladimir; Bäumler, Andreas J.

2012-01-01

Intestinal inflammation changes the luminal habitat for microbes through mechanisms that have not been fully resolved. We noticed that the FepE regulator of very long O-antigen chain assembly in the enteric pathogen Salmonella enterica serotype Typhimurium (S. Typhimurium) conferred a luminal fitness advantage in the mouse colitis model. However, a fepE mutant was not defective for survival in tissue, resistance to complement or resistance to polymyxin B. We performed metabolite profiling to identify changes in the luminal habitat that accompany S. Typhimurium-induced colitis. This analysis suggested that S. Typhimurium-induced colitis increased the luminal concentrations of total bile acids. A mutation in fepE significantly reduced the minimal inhibitory concentration (MIC) of S. Typhimurium for bile acids in vitro. Oral administration of the bile acid sequestrant cholestyramine resin lowered the concentrations of total bile acids in colon contents during S. Typhimurium infection and significantly reduced the luminal fitness advantage conferred by the fepE gene in the mouse colitis model. Collectively, these data suggested that very long O-antigen chains function in bile acid resistance of S. Typhimurium, a property conferring a fitness advantage during luminal growth in the inflamed intestine. PMID:23028318

Development of a Bile Acid-Based Newborn Screen for Niemann-Pick C Disease

PubMed Central

Jiang, Xuntian; Sidhu, Rohini; Mydock, Laurel; Hsu, Fong-Fu; Covey, Douglas F.; Scherrer, David E.; Earley, Brian; Gale, Sarah E.; Farhat, Nicole Y.; Porter, Forbes D.; Dietzen, Dennis J.; Orsini, Joseph J.; Berry-Kravis, Elizabeth; Zhang, Xiaokui; Reunert, Janice; Marquardt, Thorsten; Runz, Heiko; Giugliani, Roberto; Schaffer, Jean E.; Ory, Daniel S.

2017-01-01

Niemann-Pick disease type C (NPC) is a fatal, neurodegenerative, cholesterol storage disorder. With new therapeutics in clinical trials, it is imperative to improve diagnostics and facilitate early intervention. We used metabolomic profiling to identify potential markers and discovered three unknown bile acids that were increased in plasma from NPC but not control subjects. The bile acids most elevated in the NPC subjects were identified as 3β,5α,6β-trihydroxycholanic acid and its glycine conjugate, both of which were shown to be metabolites of cholestane-3β,5α,6β-triol, an oxysterol elevated in NPC. A high-throughput, mass spectrometry-based method was developed and validated to measure the glycine-conjugated bile acid in dried blood spots. Analysis of dried blood spots from 4992 controls, 134 NPC carriers, and 44 NPC subjects provided 100% sensitivity and specificity in the study samples. Quantification of the bile acid in dried blood spots, therefore, provides the basis for a newborn screen for NPC that is ready for piloting in newborn screening programs. PMID:27147587

Bile acid malabsorption caused by gastrointestinal motility dysfunction? An investigation of gastrointestinal disturbances in familial amyloidosis with polyneuropathy.

PubMed

Suhr, O; Danielsson, A; Steen, L

1992-01-01

Gastrointestinal dysfunction due to autonomous neuropathy is a complication described in various diseases such as diabetes mellitus, multiple sclerosis, and familial amyloidosis with polyneuropathy. We present the results of a prospective investigation of bile acid malabsorption in 17 patients with familial amyloidosis by means of 75Se-labelled homocholic-tauro acid (SeHCAT). The diagnosis was in all cases verified by the DNA test for mutation of transthyretin in position 30. Small-intestinal biopsy specimens were examined for deposits of amyloid, and the presence of gastric retention was evaluated by gastroscopy. In addition, the patients were investigated for bacterial overgrowth by means of the bile acid breath test (BABT). A high frequency of abnormal BABT results (44%) was encountered. However, 65% also had abnormal low SeHCAT values, indicating bile acid malabsorption. Only two patients had abnormal BABT and normal SeHCAT results, indicating bacterial contamination of the small intestine. Bile acid losses increased with the duration of gastrointestinal symptoms. Significantly lower SeHCAT values were encountered in patients with gastric retention, whereas the occurrence of amyloid deposits in small-intestinal biopsy specimens was without effect on SeHCAT retention. Bile acid malabsorption is frequently encountered in familial amyloidosis with polyneuropathy and seems to be more closely associated with gastrointestinal motility dysfunction than with amyloid deposits in the intestinal mucosa.

Chronic diarrhoea after radiotherapy for gynaecological cancer: occurrence and aetiology.

PubMed Central

Danielsson, A; Nyhlin, H; Persson, H; Stendahl, U; Stenling, R; Suhr, O

1991-01-01

The occurrence of chronic diarrhoea was evaluated in 173 consecutive patients previously treated with radiation for gynaecological cancer. A survey of gastrointestinal symptoms showed a high frequency of diarrhoea; 13% of the patients had 21 or more bowel movements a week and 3% had 28 or more. Significantly more patients who had a cholecystectomy were in the group with diarrhoea (chi 2 = 6.26; p less than 0.02). Twenty patients with chronic or intermittent diarrhoea were subject to extended gastrointestinal investigation. Bile acid malabsorption was evaluated by the 75Selenahomocholic acid-taurine test (SeHCAT). Bile acid malabsorption was found in 13 (65%) of the 20 patients further investigated, of whom seven had extremely low whole body retention values, which is consistent with severe malabsorption. The results suggest that bile acid malabsorption is a common cause of diarrhoea after radiation treatment for gynaecological cancer. Bacterial contamination was diagnosed in nine patients (45%) by the [14C]-D-xylose breath test or by the cholyl-[14C]-glycine breath test in combination with a normal test for bile acid malabsorption. All patients with vitamin B-12 deficiency, who were tested for bile acid malabsorption, had low retention times for the SeHCAT (p = 0.05). A significant decline in the frequency of diarrhoea was found after treatment with antibiotics or bile acid sequestrants, or both, in combination with a reduced fat diet. PMID:1955174

Intestinal absorption of the bile acid analogue 75Se-homocholic acid-taurine is increased in primary biliary cirrhosis, and reverts to normal during ursodeoxycholic acid administration

PubMed Central

Lanzini, A; De Tavonatti, M G; Panarotto, B; Scalia, S; Mora, A; Benini, F; Baisini, O; Lanzarotto, F

2003-01-01

Background: Whether ileal absorption of bile acid is up or downregulated in chronic cholestasis is still debated, and most evidence has come from animal studies. Aims: To compare ileal bile acid absorption in patients with primary biliary cirrhosis (PBC) and in healthy control subjects, and to assess the effect of ursodeoxycholic acid (UDCA). Patients: We studied 14 PBC patients before and during (n=11) UDCA administration, 14 healthy control subjects, and 14 Crohn’s disease patients (as disease controls). Methods: We used cholescintigraphy to measure retention in the enterohepatic circulation over five successive days of the bile acid analogue 75Se-homocholic acid-taurine (75SeHCAT) as an index of ileal bile acid absorption. Results were expressed as 75SeHCAT fractional turnover rate (FTR) and t½12. Results: 75SeHCAT FTR was 0.19 (0.11)/day, 0.34 (0.11)/day (p<0.001), and 0.83 (0.32)/day in PBC patients, healthy controls (p<0.0001), and Crohn’s patients (p<0.001), respectively, which increased to 0.36 (0.16)/day in PBC patients during UDCA treatment (p<0.005). 75SeHCAT t½12 was 4.8 (2.1) days in PBC patients, 2.2 (0.5) days (p<0.001) in healthy controls, and 1.0 (0.5) days (p<0.001) in Crohn’s disease patients. 75SeHCAT t½12 decreased to 2.2 (0.93) days (p< 0.001) in PBC patients during UDCA treatment. Conclusions: Our results support the concept that ileal bile acid absorption is upregulated in PBC patients, and that this effect may contribute towards damaging the cholestatic liver. This upregulation of bile acid absorption is abolished by UDCA. PMID:12912872

Bile acid malabsorption in chronic diarrhea: Pathophysiology and treatment

PubMed Central

Barkun, Alan; Love, Jonathan; Gould, Michael; Pluta, Henryk; Steinhart, A Hillary

2013-01-01

BACKGROUND: Bile acid malabsorption (BAM) is a common but frequently under-recognized cause of chronic diarrhea, with an estimated prevalence of 4% to 5%. METHODS: The published literature for the period 1965 to 2012 was examined for articles regarding the pathophysiology and treatment of BAM to provide an overview of the management of BAM in gastroenterology practice. RESULTS: BAM is classified as type 1 (secondary to ileal dysfunction), type 2 (idiopathic) or type 3 (secondary to gastrointestinal disorders not associated with ileal dysfunction). The estimated prevalence of BAM is >90% in patients with resected Crohn disease (CD) and 11% to 52% of unresected CD patients (type 1); 33% in diarrhea-predominant irritable bowel syndrome (type 2); and is a frequent finding postcholecystectomy or postvagotomy (type 3). Investigations include BAM fecal bile acid assay, 23-seleno-25-homo-tauro-cholic acid (SeHCAT) testing and high-performance liquid chromatography of serum 7-α-OH-4-cholesten-3-one (C4), to determine the level of bile acid synthesis. A less time-consuming and expensive alternative in practice is an empirical trial of the bile acid sequestering agent cholestyramine. An estimated 70% to 96% of chronic diarrhea patients with BAM respond to short-course cholestyramine. Adverse effects include constipation, nausea, borborygmi, flatulence, bloating and abdominal pain. Other bile acid sequestering agents, such as colestipol and colesevelam, are currently being investigated for the treatment of BAM-associated diarrhea. CONCLUSIONS: BAM is a common cause of chronic diarrhea presenting in gastroenterology practice. In accordance with current guidelines, an empirical trial of a bile acid sequestering agent is warranted as part of the clinical workup to rule out BAM. PMID:24199211

Prevalence of, and predictors of, bile acid malabsorption in outpatients with chronic diarrhea.

PubMed

Gracie, D J; Kane, J S; Mumtaz, S; Scarsbrook, A F; Chowdhury, F U; Ford, A C

2012-11-01

Many physicians do not consider the diagnosis of bile acid malabsorption in patients with chronic diarrhea, or do not have access to testing. We examined yield of 23-seleno-25-homo-tauro-cholic acid (SeHCAT) scanning in chronic diarrhea patients, and attempted to identify predictors of a positive test. Consecutive patients with chronic diarrhea undergoing SeHCAT scan over a 7-year period were identified retrospectively. Bile acid malabsorption was defined as present at a retention of <15%. Medical records were reviewed to obtain information regarding proposed risk factors. Gastrointestinal symptoms were recorded, and patients were classified as having diarrhea-predominant irritable bowel syndrome (IBS-D) if they reported abdominal pain or discomfort. Independent risk factors were assessed using multivariate logistic regression, and odds ratios (ORs) with 99% confidence intervals (CIs) were calculated. Of 373 patients, 190 (50.9%) had bile acid malabsorption. Previous cholecystectomy (OR 2.51; 99% CI 1.10-5.77), terminal ileal resection or right hemicolectomy for Crohn's disease (OR 12.4; 99% CI 2.42-63.8), and terminal ileal resection or right hemicolectomy for other reasons (OR 7.94; 99% CI 1.02-61.6) were associated with its presence. Seventy-seven patients had IBS-D, and 21 (27.3%) tested positive. There were 168 patients with no risk factors for a positive SeHCAT scan, other than chronic diarrhea, and 63 (37.5%) had bile acid malabsorption. Bile acid malabsorption was present in 50% of patients undergoing SeHCAT scanning. Almost 40% of those without risk factors had evidence of bile acid malabsorption, and in those meeting criteria for IBS-D prevalence was almost 30%. © 2012 Blackwell Publishing Ltd.

N-(4-[18F]fluorobenzyl)cholylglycine, a novel tracer for PET of enterohepatic circulation of bile acids: Radiosynthesis and proof-of-concept studies in rats.

PubMed

Frisch, Kim; Stimson, Damion H R; Venkatachalam, Taracad; Pierens, Gregory K; Keiding, Susanne; Reutens, David; Bhalla, Rajiv

2018-05-04

Enterohepatic circulation (EHC) of conjugated bile acids is an important physiological process crucial for regulation of intracellular concentrations of bile acids and their function as detergents and signal carriers. Only few bile acid-derived imaging agents have been synthesized and hitherto none have been evaluated for studies of EHC. We hypothesized that N-(4-[ 18 F]fluorobenzyl)cholylglycine ([ 18 F]FBCGly), a novel fluorine-18 labeled derivative of endogenous cholylglycine, would be a suitable tracer for PET of the EHC of conjugated bile acids, and we report here a radiosynthesis of [ 18 F]FBCGly and a proof-of-concept study by PET/MR in rats. A radiosynthesis of [ 18 F]FBCGly was developed based on reductive alkylation of glycine with 4-[ 18 F]fluorobenzaldehyde followed by coupling to cholic acid. [ 18 F]FBCGly was investigated in vivo by dynamic PET/MR in anesthetized rats; untreated or treated with cholyltaurine or rifampicin. Possible in vivo metabolites of [ 18 F]FBCGly were investigated by analysis of blood and bile samples, and the stability of [ 18 F]FBCGly towards enzymatic de-conjugation by Cholylglycine Hydrolase was tested in vitro. [ 18 F]FBCGly was produced with a radiochemical purity of 96% ± 1% and a non-decay corrected radiochemical yield of 1.0% ± 0.3% (mean ± SD; n = 12). PET/MR studies showed that i.v.-administrated [ 18 F]FBCGly underwent EHC within 40-60 min with a rapid transhepatic transport from blood to bile. In untreated rats, the radioactivity concentration of [ 18 F]FBCGly was approximately 15 times higher in bile than in liver tissue. Cholyltaurine and rifampicin inhibited the biliary secretion of [ 18 F]FBCGly. No fluorine-18 metabolites of [ 18 F]FBCGly were observed. We have developed a radiosynthesis of a novel fluorine-18 labeled bile acid derivative, [ 18 F]FBCGly, and shown by PET/MR that [ 18 F]FBCGly undergoes continuous EHC in rats without metabolizing. This novel tracer may prove useful in PET studies on the effect of drugs or diseases on the EHC of conjugated bile acids. Copyright © 2018 Elsevier Inc. All rights reserved.

The effects of micronutrient deficiencies on bacterial species from the human gut microbiota

PubMed Central

Hibberd, Matthew C.; Wu, Meng; Rodionov, Dmitry A.; Li, Xiaoqing; Cheng, Jiye; Griffin, Nicholas W.; Barratt, Michael J.; Giannone, Richard J.; Hettich, Robert L.; Osterman, Andrei L.; Gordon, Jeffrey I.

2017-01-01

Vitamin and mineral (micronutrient) deficiencies afflict two billion people. While the impact of these imbalances on host biology has been studied extensively, much less is known about their effects on the gut microbiota of developing or adult humans. Therefore, we established a community of cultured, sequenced human gut-derived bacterial species in gnotobiotic mice and fed the animals a defined micronutrient-sufficient diet, followed by a derivative diet devoid of vitamin A, folate, iron or zinc, followed by return to the sufficient diet. Acute vitamin A deficiency had the largest effect on bacterial community structure and meta-transcriptome, with Bacteroides vulgatus, a prominent responder, increasing its abundance in the absence of vitamin A. Applying retinol selection to a library of 30,300 B. vulgatus transposon mutants revealed that disruption of acrR abrogated retinol sensitivity. Genetic complementation studies, microbial RNA-Seq, and transcription factor binding assays disclosed that AcrR is a repressor of an adjacent AcrAB-TolC efflux system. Retinol efflux measurements in wildtype and acrR-mutant strains plus treatment with a pharmacologic inhibitor of the efflux system, revealed that AcrAB-TolC is a determinant of retinol and bile acid sensitivity in B. vulgatus. Acute vitamin A deficiency was associated with altered bile acid metabolism in vivo, raising the possibility that retinol, bile acid metabolites, and AcrAB-TolC interact to influence the fitness of B. vulgatus and perhaps other microbiota members. This type of preclinical model can help to develop mechanistic insights about and more effective treatment strategies for micronutrient deficiencies. PMID:28515336

Non-cholesterol sterols and cholesterol metabolism in sitosterolemia.

PubMed

Othman, Rgia A; Myrie, Semone B; Jones, Peter J H

2013-12-01

Sitosterolemia (STSL) is a rare autosomal recessive disease, manifested by extremely elevated plant sterols (PS) in plasma and tissue, leading to xanthoma and premature atherosclerotic disease. Therapeutic approaches include limiting PS intake, interrupting enterohepatic circulation of bile acid using bile acid binding resins such as cholestyramine, and/or ileal bypass, and inhibiting intestinal sterol absorption by ezetimibe (EZE). The objective of this review is to evaluate sterol metabolism in STSL and the impact of the currently available treatments on sterol trafficking in this disease. The role of PS in initiation of xanthomas and premature atherosclerosis is also discussed. Blocking sterols absorption with EZE has revolutionized STSL patient treatment as it reduces circulating levels of non-cholesterol sterols in STSL. However, none of the available treatments including EZE have normalized plasma PS concentrations. Future studies are needed to: (i) explore where cholesterol and non-cholesterol sterols accumulate, (ii) assess to what extent these sterols in tissues can be mobilized after blocking their absorption, and (iii) define the factors governing sterol flux. Copyright © 2013. Published by Elsevier Ireland Ltd.

Biochemical basis for activation of virulence genes by bile salts in Vibrio parahaemolyticus

PubMed Central

2017-01-01

ABSTRACT Bile salts act as a stressor to bacteria that transit the intestinal tract. Enteric pathogens have hijacked bile as an intestinal signal to regulate virulence factors. We recently demonstrated that Vibrio parahemolyticus senses bile salts via a heterodimeric receptor formed by the periplasmic domains of inner-membrane proteins VtrA and VtrC. Crystal structures of the periplasmic complex reveal that VtrA and VtrC form a β-barrel that binds bile salts in its hydrophobic interior to activate the VtrA cytoplasmic DNA-binding domain. Proteins with the same domain arrangement as VtrA and VtrC are widespread in Vibrio and related bacteria, where they are involved in regulating virulence and other unknown functions. Here we discuss our findings and review current knowledge on VtrA and VtrC homologs. We propose that signaling by these membrane-bound transcription factors can be advantageous for the regulation of membrane and secretory proteins. PMID:28129014

History of Hepatic Bile Formation: Old Problems, New Approaches

ERIC Educational Resources Information Center

Javitt, Norman B.

2014-01-01

Studies of hepatic bile formation reported in 1958 established that it was an osmotically generated water flow. Intravenous infusion of sodium taurocholate established a high correlation between hepatic bile flow and bile acid excretion. Secretin, a hormone that stimulates bicarbonate secretion, was also found to increase hepatic bile flow. The…

Bile acid signaling in lipid metabolism: Metabolomic and lipidomic analysis of lipid and bile acid markers linked to anti-obesity and anti-diabetes in mice

PubMed Central

Qi, Yunpeng; Jiang, Changtao; Cheng, Jie; Krausz, Kristopher W.; Li, Tiangang; Ferrell, Jessica M.; Gonzalez, Frank J.; Chiang, John Y.L.

2014-01-01

Bile acid synthesis is the major pathway for catabolism of cholesterol. Cholesterol 7α-hydroxylase (CYP7A1) is the rate-limiting enzyme in the bile acid biosynthetic pathway in the liver and plays an important role in regulating lipid, glucose and energy metabolism. Transgenic mice overexpressing CYP7A1 (CYP7A1-tg mice) were resistant to high-fat diet (HFD)-induced obesity, fatty liver, and diabetes. However the mechanism of resistance to HFD-induced obesity of CYP7A1-tg mice has not been determined. In this study, metabolomic and lipidomic profiles of CYP7A1-tg mice were analyzed to explore the metabolic alterations in CYP7A1-tg mice that govern the protection against obesity and insulin resistance by using ultra-performance liquid chromatography-coupled with electrospray ionization quadrupole time-of-flight mass spectrometry combined with multivariate analyses. Lipidomics analysis identified seven lipid markers including lysophosphatidylcholines, phosphatidylcholines, sphingomyelins and ceramides that were significantly decreased in serum of HFD-fed CYP7A1-tg mice. Metabolomics analysis identified 13 metabolites in bile acid synthesis including taurochenodeoxycholic acid, taurodeoxycholic acid, tauroursodeoxycholic acid, taurocholic acid, and tauro-β-muricholic acid (T-β-MCA) that differed between CYP7A1-tg and wild-type mice. Notably, T-β-MCA, an antagonist of the farnesoid X receptor (FXR) was significantly increased in intestine of CYP7A1-tg mice. This study suggests that reducing 12α-hydroxylated bile acids and increasing intestinal T-β-MCA may reduce high fat diet-induced increase of phospholipids, sphingomyelins and ceramides, and ameliorate diabetes and obesity. PMID:24796972

IL-17A Synergistically Enhances Bile Acid–Induced Inflammation during Obstructive Cholestasis

PubMed Central

O'Brien, Kate M.; Allen, Katryn M.; Rockwell, Cheryl E.; Towery, Keara; Luyendyk, James P.; Copple, Bryan L.

2014-01-01

During obstructive cholestasis, increased concentrations of bile acids activate ERK1/2 in hepatocytes, which up-regulates early growth response factor 1, a key regulator of proinflammatory cytokines, such as macrophage inflammatory protein 2 (MIP-2), which, in turn, exacerbates cholestatic liver injury. Recent studies have indicated that IL-17A contributes to hepatic inflammation during obstructive cholestasis, suggesting that bile acids and IL-17A may interact to regulate hepatic inflammatory responses. We treated mice with an IL-17A neutralizing antibody or control IgG and subjected them to bile duct ligation. Neutralization of IL-17A prevented up-regulation of proinflammatory cytokines, hepatic neutrophil accumulation, and liver injury, indicating an important role for IL-17A in neutrophilic inflammation during cholestasis. Treatment of primary mouse hepatocytes with taurocholic acid (TCA) increased the expression of MIP-2. Co-treatment with IL-17A synergistically enhanced up-regulation of MIP-2 by TCA. In contrast to MIP-2, IL-17A did not affect up-regulation of Egr-1 by TCA, indicating that IL-17A does not affect bile acid–induced activation of signaling pathways upstream of early growth response factor 1. In addition, bile acids increased expression of IL-23, a key regulator of IL-17A production in hepatocytes in vitro and in vivo. Collectively, these data identify bile acids as novel triggers of the IL-23/IL-17A axis and suggest that IL-17A promotes hepatic inflammation during cholestasis by synergistically enhancing bile acid–induced production of proinflammatory cytokines by hepatocytes. PMID:24012680

A nuclear-receptor-dependent phosphatidylcholine pathway with antidiabetic effects.

PubMed

Lee, Jae Man; Lee, Yoon Kwang; Mamrosh, Jennifer L; Busby, Scott A; Griffin, Patrick R; Pathak, Manish C; Ortlund, Eric A; Moore, David D

2011-05-25

Nuclear hormone receptors regulate diverse metabolic pathways and the orphan nuclear receptor LRH-1 (also known as NR5A2) regulates bile acid biosynthesis. Structural studies have identified phospholipids as potential LRH-1 ligands, but their functional relevance is unclear. Here we show that an unusual phosphatidylcholine species with two saturated 12 carbon fatty acid acyl side chains (dilauroyl phosphatidylcholine (DLPC)) is an LRH-1 agonist ligand in vitro. DLPC treatment induces bile acid biosynthetic enzymes in mouse liver, increases bile acid levels, and lowers hepatic triglycerides and serum glucose. DLPC treatment also decreases hepatic steatosis and improves glucose homeostasis in two mouse models of insulin resistance. Both the antidiabetic and lipotropic effects are lost in liver-specific Lrh-1 knockouts. These findings identify an LRH-1 dependent phosphatidylcholine signalling pathway that regulates bile acid metabolism and glucose homeostasis.

Boldine enhances bile production in rats via osmotic and farnesoid X receptor dependent mechanisms.

PubMed

Cermanova, Jolana; Kadova, Zuzana; Zagorova, Marie; Hroch, Milos; Tomsik, Pavel; Nachtigal, Petr; Kudlackova, Zdenka; Pavek, Petr; Dubecka, Michaela; Ceckova, Martina; Staud, Frantisek; Laho, Tomas; Micuda, Stanislav

2015-05-15

Boldine, the major alkaloid from the Chilean Boldo tree, is used in traditional medicine to support bile production, but evidence to support this function is controversial. We analyzed the choleretic potential of boldine, including its molecular background. The acute- and long-term effects of boldine were evaluated in rats either during intravenous infusion or after 28-day oral treatment. Infusion of boldine instantly increased the bile flow 1.4-fold in healthy rats as well as in animals with Mrp2 deficiency or ethinylestradiol induced cholestasis. This effect was not associated with a corresponding increase in bile acid or glutathione biliary excretion, indicating that the effect is not related to stimulation of either bile acid dependent or independent mechanisms of bile formation and points to the osmotic activity of boldine itself. We subsequently analyzed bile production under conditions of changing biliary excretion of boldine after bolus intravenous administration and found strong correlations between both parameters. HPLC analysis showed that bile concentrations of boldine above 10 μM were required for induction of choleresis. Importantly, long-term pretreatment, when the bile collection study was performed 24-h after the last administration of boldine, also accelerated bile formation despite undetectable levels of the compound in bile. The effect paralleled upregulation of the Bsep transporter and increased biliary clearance of its substrates, bile acids. We consequently confirmed the ability of boldine to stimulate the Bsep transcriptional regulator, FXR receptor. In conclusion, our study clarified the mechanisms and circumstances surrounding the choleretic activity of boldine. Copyright © 2015 Elsevier Inc. All rights reserved.

Easy preparation of dietary fiber with the high water-holding capacity from food sources.

PubMed

Yamazaki, Eiji; Murakami, Kazumi; Kurita, Osamu

2005-03-01

Dietary fibers were prepared as alkali- and acid-insoluble fractions with chemical phosphorylation from Tossa jute (Corchorus olitorius), defatted soybean (Glycine max), and Shiitake (Lentinula edodes). The dietary fiber fractions treated with alkaline solution containing sodium metaphosphate had the lower protein content and higher total dietary fiber content than those of the preparations without phosphorylation. Alkaline extraction followed by phosphorylation led to a 1.5-fold increase in the water holding capacity of dietary fiber compared with no phosphorylation, whereas the binding capacity to bile acids of dietary fiber was almost the same. The alkali- and acid-insoluble extraction with phosphorylation provided an efficient preparation of water-insoluble dietary fiber with high-water holding capacity from various food sources.

[Combined action of nitrofuran preparations and bile acids on staphylococci].

PubMed

Tkachuk, N I

1984-03-01

The effect of cholic, glycocholic and deoxycholic bile acids on the antimicrobial activity of furacin, furadonin, furagin and furoxone was studied with the use of collection strains and fresh isolates of staphylococci. The method of dilutions in liquid media was used. Cholic and glycocholic acids lowered the MIC of furacin, furadonin, furoxone and furagin with respect to the collection strains by 4-16, 5, 4-6 and 22-37 times, respectively. The potentiating effect of deoxycholic acid on the nitrofuran drugs was even more pronounced. Thus, when the nitrofurans were used in combination with deoxycholic acid, their MIC dropped by 16-114 times. A significant increase in the antimicrobial activity of the nitrofurans under the effect of the bile acids was also observed with respect to the fresh isolates of Staphylococcus, while it was somewhat lower. The subbacteriostatic doses of cholic, glycocholic and deoxycholic bile acids also increased the bactericidal effect of the nitrofuran drugs. The minimum bactericidal concentrations (MBC) of furacin, furoxone, furadonin and furagin decreased from 12.5, 2.08, 25.0 and 1.82 to 0.78, 0.26, 2.34 and 0.032 micrograms/ml, respectively. The most pronounced decrease in the MBC was observed under the effect of deoxycholic acid. Therefore, the bile acids potentiated the nitrofuran antistaphylococcal activity. The combinations of deoxycholic acid with furagin or furoxone were the most effective.

The bile acids, deoxycholic acid and ursodeoxycholic acid, regulate colonic epithelial wound healing.

PubMed

Mroz, Magdalena S; Lajczak, Natalia K; Goggins, Bridie J; Keely, Simon; Keely, Stephen J

2018-03-01

The intestinal epithelium constitutes an innate barrier which, upon injury, undergoes self-repair processes known as restitution. Although bile acids are known as important regulators of epithelial function in health and disease, their effects on wound healing processes are not yet clear. Here we set out to investigate the effects of the colonic bile acids, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA), on epithelial restitution. Wound healing in T 84 cell monolayers grown on transparent, permeable supports was assessed over 48 h with or without bile acids. Cell migration was measured in Boyden chambers. mRNA and protein expression were measured by RT-PCR and Western blotting. DCA (50-150 µM) significantly inhibited wound closure in cultured epithelial monolayers and attenuated cell migration in Boyden chamber assays. DCA also induced nuclear accumulation of the farnesoid X receptor (FXR), whereas an FXR agonist, GW4064 (10 µM), inhibited wound closure. Both DCA and GW4064 attenuated the expression of CFTR Cl - channels, whereas inhibition of CFTR activity with either CFTR- inh -172 (10 µM) or GlyH-101 (25 µM) also prevented wound healing. Promoter/reporter assays revealed that FXR-induced downregulation of CFTR is mediated at the transcriptional level. In contrast, UDCA (50-150 µM) enhanced wound healing in vitro and prevented the effects of DCA. Finally, DCA inhibited and UDCA promoted mucosal healing in an in vivo mouse model. In conclusion, these studies suggest bile acids are important regulators of epithelial wound healing and are therefore good targets for development of new drugs to modulate intestinal barrier function in disease treatment. NEW & NOTEWORTHY The secondary bile acid, deoxycholic acid, inhibits colonic epithelial wound healing, an effect which appears to be mediated by activation of the nuclear bile acid receptor, FXR, with subsequent downregulation of CFTR expression and activity. In contrast, ursodeoxycholic acid promotes wound healing, suggesting it may provide an alternative approach to prevent the losses of barrier function that are associated with mucosal inflammation in IBD patients.

Irinotecan (CPT-11)-induced elevation of bile acids potentiates suppression of IL-10 expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fang, Zhong-Ze; Department of Toxicology, School of Public Health, Tianjin Medical University, Tianjin; Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and First Affiliated Hospital of Liaoning Medical University, Dalian

Irinotecan (CPT-11) is a first-line anti-colon cancer drug, however; CPT-11-induced toxicity remains a key factor limiting its clinical application. To search for clues to the mechanism of CPT-11-induced toxicity, metabolomics was applied using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry. Intraperitoneal injection of 50 mg/kg of CPT-11 induced loss of body weight, and intestine toxicity. Changes in gallbladder morphology suggested alterations in bile acid metabolism, as revealed at the molecular level by analysis of the liver, bile, and ileum metabolomes between the vehicle-treated control group and the CPT-11-treated group. Analysis of immune cell populations further showedmore » that CPT-11 treatment significantly decreased the IL-10-producing CD4 T cell frequency in intestinal lamina propria lymphocytes, but not in spleen or mesenteric lymph nodes. In vitro cell culture studies showed that the addition of bile acids deoxycholic acid and taurodeoxycholic acid accelerated the CPT-11-induced suppression of IL-10 secretion by activated CD4{sup +} naive T cells isolated from mouse splenocytes. These results showed that CPT-11 treatment caused metabolic changes in the composition of bile acids that altered CPT-11-induced suppression of IL-10 expression. - Highlights: • CPT-11 is an effective anticancer drug, but induced toxicity limits its application in the clinic. • CPT-11 decreased IL-10-producing CD4 T cell frequency in intestinal lamina propria lymphocytes. • CPT-11 altered the composition of bile acid metabolites, notably DCA and TDCA in liver, bile and intestine. • DCA and TDCA potentiated CPT-11-induced suppression of IL-10 secretion by active CD4{sup +} naive T cells.« less

Pepsin and bile acids in saliva in patients with laryngopharyngeal reflux - a prospective comparative study.

PubMed

Sereg-Bahar, M; Jerin, A; Jansa, R; Stabuc, B; Hocevar-Boltezar, I

2015-06-01

Laryngopharyngeal reflux (LPR) and biliary duodenogastric reflux can cause damage to the laryngeal mucosa and voice disorders. The aim of this study was to find out whether levels of pepsin and bile acids in the saliva can serve as diagnostic markers of LPR. A prospective comparative study. Twenty-eight patients with LPR proven via high-resolution manometry and combined multichannel intraluminal impedance and 24-h pH monitoring and 48 healthy controls without symptoms of LPR were included in the study. In the patients with LPR symptoms, oesophagogastroscopy with oesophageal biopsy was performed. The levels of total pepsin, active pepsin, bile acids and the pH of the saliva were determined in all participants and compared between the groups. Reflux symptom index (RSI) and reflux finding score (RFS) were also obtained and compared. The groups differed significantly in RSI (P = 0.00), RFS (P = 0.00), the levels of bile acids (P = 0.005) and total pepsin in saliva (P = 0.023). The levels of total pepsin and bile acids were about three times higher in the patients with LPR than in the healthy controls. There was a significant correlation between the RSI and RFS score and the level of total pepsin and bile acids in the saliva. Histopathological examination of the oesophageal biopsy taken 5 cm above the lower oesophageal sphincter confirmed reflux in almost 93% of patients with symptoms. The study results show that the levels of total pepsin and bile acids in saliva are significantly higher in patients with LPR than in the controls, thus suggesting this as a useful tool in the diagnosis of LPR and particularly biliary LPR. © 2014 John Wiley & Sons Ltd.

Liver Dysfunction and Phosphatidylinositol-3-Kinase Signalling in Early Sepsis: Experimental Studies in Rodent Models of Peritonitis

PubMed Central

Westermann, Martin; Lambeck, Sandro; Lupp, Amelie; Rudiger, Alain; Dyson, Alex; Carré, Jane E.; Kortgen, Andreas; Krafft, Christoph; Popp, Jürgen; Sponholz, Christoph; Fuhrmann, Valentin; Hilger, Ingrid; Claus, Ralf A.; Riedemann, Niels C.; Wetzker, Reinhard; Singer, Mervyn; Trauner, Michael; Bauer, Michael

2012-01-01

Background Hepatic dysfunction and jaundice are traditionally viewed as late features of sepsis and portend poor outcomes. We hypothesized that changes in liver function occur early in the onset of sepsis, yet pass undetected by standard laboratory tests. Methods and Findings In a long-term rat model of faecal peritonitis, biotransformation and hepatobiliary transport were impaired, depending on subsequent disease severity, as early as 6 h after peritoneal contamination. Phosphatidylinositol-3-kinase (PI3K) signalling was simultaneously induced at this time point. At 15 h there was hepatocellular accumulation of bilirubin, bile acids, and xenobiotics, with disturbed bile acid conjugation and drug metabolism. Cholestasis was preceded by disruption of the bile acid and organic anion transport machinery at the canalicular pole. Inhibitors of PI3K partially prevented cytokine-induced loss of villi in cultured HepG2 cells. Notably, mice lacking the PI3Kγ gene were protected against cholestasis and impaired bile acid conjugation. This was partially confirmed by an increase in plasma bile acids (e.g., chenodeoxycholic acid [CDCA] and taurodeoxycholic acid [TDCA]) observed in 48 patients on the day severe sepsis was diagnosed; unlike bilirubin (area under the receiver-operating curve: 0.59), these bile acids predicted 28-d mortality with high sensitivity and specificity (area under the receiver-operating curve: CDCA: 0.77; TDCA: 0.72; CDCA+TDCA: 0.87). Conclusions Liver dysfunction is an early and commonplace event in the rat model of sepsis studied here; PI3K signalling seems to play a crucial role. All aspects of hepatic biotransformation are affected, with severity relating to subsequent prognosis. Detected changes significantly precede conventional markers and are reflected by early alterations in plasma bile acids. These observations carry important implications for the diagnosis of liver dysfunction and pharmacotherapy in the critically ill. Further clinical work is necessary to extend these concepts into clinical practice. Please see later in the article for the Editors' Summary PMID:23152722

Ca2+-Dependent Cytoprotective Effects of Ursodeoxycholic and Tauroursodeoxycholic Acid on the Biliary Epithelium in a Rat Model of Cholestasis and Loss of Bile Ducts

PubMed Central

Marzioni, Marco; Francis, Heather; Benedetti, Antonio; Ueno, Yoshiyuki; Fava, Giammarco; Venter, Juliet; Reichenbach, Ramona; Mancino, Maria Grazia; Summers, Ryun; Alpini, Gianfranco; Glaser, Shannon

2006-01-01

Chronic cholestatic liver diseases are characterized by impaired balance between proliferation and death of cholangiocytes, as well as vanishing of bile ducts and liver failure. Ursodeoxycholic acid (UDCA) is a bile acid widely used for the therapy of cholangiopathies. However, little is known of the cytoprotective effects of UDCA on cholangiocytes. Therefore, UDCA and its taurine conjugate tauroursodeoxycholic acid (TUDCA) were administered in vivo to rats simultaneously subjected to bile duct ligation and vagotomy, a model that induces cholestasis and loss of bile ducts by apoptosis of cholangiocytes. Because these two bile acids act through Ca2+ signaling, animals were also treated with BAPTA/AM (an intracellular Ca2+ chelator) or Gö6976 (a Ca2+-dependent protein kinase C-α inhibitor). The administration of UDCA or TUDCA prevented the induction of apoptosis and the loss of proliferative and functional responses observed in the bile duct ligation-vagotomized rats. These effects were neutralized by the simultaneous administration of BAPTA/AM or Gö6976. UDCA and TUDCA enhanced intracellular Ca2+ and IP3 levels, together with increased phosphorylation of protein kinase C-α. Parallel changes were observed regarding the activation of the MAPK and PI3K pathways, changes that were abolished by addition of BAPTA/AM or Gö6976. These studies provide information that may improve the response of cholangiopathies to medical therapy. PMID:16436655

Role of phospholipase A2 in cholesterol gallstone formation is associated with biliary phospholipid species selection at the site of hepatic excretion: indirect evidence.

PubMed

Hattori, Y; Tazuma, S; Yamashita, G; Ochi, H; Sunami, Y; Nishioka, T; Hyogo, H; Yasumiba, S; Kajihara, T; Nakai, K; Tsuboi, K; Asamoto, Y; Sakomoto, M; Kajiyama, G

2000-07-01

Phospholipase A2 plays a role in cholesterol gallstone development by hydrolyzing bile phospholipids into lysolecithin and free fatty acids. Lysolecithin and polyunsaturated free fatty acids are known to stimulate the synthesis and/or secretion of gallbladder mucin via a prostanoid pathway, leading to enhancing cholesterol crystal nucleation and growth, and therefore, the action of phospholipase A2 is associated, in part, with bile phospholipid fatty acid. To clarify this hypothesis, we evaluated the effect on bile lipid metastability in vitro of replacing phospholipids with lysolecithin and various free fatty acids. Supersaturated model biles were created with an identical composition (cholesterol saturation index, 1.8; egg yolk lecithin, 34 mM; taurocholate, 120 mM; cholesterol, 25 mM) except for 5%, 10%, or 20% replacement of egg yolk lecithin with a combination of palmitoyl-lysolecithin and a free fatty acid (palmitate, stearate, oleate, linoleate, or arachidonate), followed by time-sequentially monitoring of vesicles and cholesterol crystals using spectrophotometer and video-enhanced differential contrast microscopy. Replacement with hydrophilic fatty acids (linoleate and arachidonate) reduced vesicle formation and promoted cholesterol crystallization, whereas an enhanced cholesterol-holding capacity was evident after replacement with hydrophobic fatty acids (palmitate and stearate). These results indicate that the effect of phospholipase A2 on bile lithogenecity is modulated by the fatty acid species in bile phospholipids, and therefore, that the role of phospholipase A2 in cholesterol gallstone formation is dependent, in part, on biliary phospholipid species selection at the site of hepatic excretion.

Molecular cloning and expression of rat liver bile acid CoA ligase.

PubMed

Falany, Charles N; Xie, Xiaowei; Wheeler, James B; Wang, Jin; Smith, Michelle; He, Dongning; Barnes, Stephen

2002-12-01

Bile acid CoA ligase (BAL) is responsible for catalyzing the first step in the conjugation of bile acids with amino acids. Sequencing of putative rat liver BAL cDNAs identified a cDNA (rBAL-1) possessing a 51 nucleotide 5'-untranslated region, an open reading frame of 2,070 bases encoding a 690 aa protein with a molecular mass of 75,960 Da, and a 138 nucleotide 3'-nontranslated region followed by a poly(A) tail. Identity of the cDNA was established by: 1) the rBAL-1 open reading frame encoded peptides obtained by chemical sequencing of the purified rBAL protein; 2) expressed rBAL-1 protein comigrated with purified rBAL during SDS-polyacrylamide gel electrophoresis; and 3) rBAL-1 expressed in insect Sf9 cells had enzymatic properties that were comparable to the enzyme isolated from rat liver. Evidence for a relationship between fatty acid and bile acid metabolism is suggested by specific inhibition of rBAL-1 by cis-unsaturated fatty acids and its high homology to a human very long chain fatty acid CoA ligase. In summary, these results indicate that the cDNA for rat liver BAL has been isolated and expression of the rBAL cDNA in insect Sf9 cells results in a catalytically active enzyme capable of utilizing several different bile acids as substrates.

Contribution of the 7β-hydroxysteroid dehydrogenase from Ruminococcus gnavus N53 to ursodeoxycholic acid formation in the human colon.

PubMed

Lee, Ja-Young; Arai, Hisashi; Nakamura, Yusuke; Fukiya, Satoru; Wada, Masaru; Yokota, Atsushi

2013-11-01

Bile acid composition in the colon is determined by bile acid flow in the intestines, the population of bile acid-converting bacteria, and the properties of the responsible bacterial enzymes. Ursodeoxycholic acid (UDCA) is regarded as a chemopreventive beneficial bile acid due to its low hydrophobicity. However, it is a minor constituent of human bile acids. Here, we characterized an UDCA-producing bacterium, N53, isolated from human feces. 16S rDNA sequence analysis identified this isolate as Ruminococcus gnavus, a novel UDCA-producer. The forward reaction that produces UDCA from 7-oxo-lithocholic acid was observed to have a growth-dependent conversion rate of 90-100% after culture in GAM broth containing 1 mM 7-oxo-lithocholic acid, while the reverse reaction was undetectable. The gene encoding 7β-hydroxysteroid dehydrogenase (7β-HSDH), which facilitates the UDCA-producing reaction, was cloned and overexpressed in Escherichia coli. Characterization of the purified 7β-HSDH revealed that the kcat/Km value was about 55-fold higher for the forward reaction than for the reverse reaction, indicating that the enzyme favors the UDCA-producing reaction. As R. gnavus is a common, core bacterium of the human gut microbiota, these results suggest that this bacterium plays a pivotal role in UDCA formation in the colon.

Contribution of the 7β-hydroxysteroid dehydrogenase from Ruminococcus gnavus N53 to ursodeoxycholic acid formation in the human colon[S

PubMed Central

Lee, Ja-Young; Arai, Hisashi; Nakamura, Yusuke; Fukiya, Satoru; Wada, Masaru; Yokota, Atsushi

2013-01-01

Bile acid composition in the colon is determined by bile acid flow in the intestines, the population of bile acid-converting bacteria, and the properties of the responsible bacterial enzymes. Ursodeoxycholic acid (UDCA) is regarded as a chemopreventive beneficial bile acid due to its low hydrophobicity. However, it is a minor constituent of human bile acids. Here, we characterized an UDCA-producing bacterium, N53, isolated from human feces. 16S rDNA sequence analysis identified this isolate as Ruminococcus gnavus, a novel UDCA-producer. The forward reaction that produces UDCA from 7-oxo-lithocholic acid was observed to have a growth-dependent conversion rate of 90–100% after culture in GAM broth containing 1 mM 7-oxo-lithocholic acid, while the reverse reaction was undetectable. The gene encoding 7β-hydroxysteroid dehydrogenase (7β-HSDH), which facilitates the UDCA-producing reaction, was cloned and overexpressed in Escherichia coli. Characterization of the purified 7β-HSDH revealed that the kcat/Km value was about 55-fold higher for the forward reaction than for the reverse reaction, indicating that the enzyme favors the UDCA-producing reaction. As R. gnavus is a common, core bacterium of the human gut microbiota, these results suggest that this bacterium plays a pivotal role in UDCA formation in the colon. PMID:23729502

Antidiabetic actions of a phosphatidylcholine ligand for nuclear receptor LRH-1

PubMed Central

Lee, Jae Man; Lee, Yoon Kwang; Mamrosh, Jennifer L.; Busby, Scott A.; Griffin, Patrick R.; Pathak, Manish C.; Ortlund, Eric A.; Moore, David D.

2011-01-01

Nuclear hormone receptors regulate diverse metabolic pathways and the orphan nuclear receptor LRH-1 (NR5A2) regulates bile acid biosynthesis1,2. Structural studies have identified phospholipids as potential LRH-1 ligands3–5, but their functional relevance is unclear. Here we show that an unusual phosphatidylcholine species with two saturated 12 carbon fatty acid acyl side chains (dilauroyl phosphatidylcholine, DLPC) is an LRH-1 agonist ligand in vitro. DLPC treatment induces bile acid biosynthetic enzymes in mouse liver, increases bile acid levels, and lowers hepatic triglycerides and serum glucose. DLPC treatment also decreases hepatic steatosis and improves glucose homeostasis in two mouse models of insulin resistance. Both the antidiabetic and lipotropic effects are lost in liver specific Lrh-1 knockouts. These findings identify an LRH-1 dependent phosphatidylcholine signaling pathway that regulates bile acid metabolism and glucose homeostasis. PMID:21614002

The Cholangiocyte Glycocalyx Stabilizes the 'Biliary HCO3 Umbrella': An Integrated Line of Defense against Toxic Bile Acids.

PubMed

Maillette de Buy Wenniger, Lucas J; Hohenester, Simon; Maroni, Luca; van Vliet, Sandra J; Oude Elferink, Ronald P; Beuers, Ulrich

2015-01-01

Destruction of cholangiocytes is the hallmark of chronic cholangiopathies such as primary biliary cirrhosis. Under physiologic conditions, cholangiocytes display a striking resistance to the high, millimolar concentrations of toxic bile salts present in bile. We recently showed that a 'biliary HCO3(-) umbrella', i.e. apical cholangiocellular HCO3(-) secretion, prevents cholangiotoxicity of bile acids, and speculated on a role for extracellular membrane-bound glycans in the stabilization of this protective layer. This paper summarizes published and thus far unpublished evidence supporting the role of the glycocalyx in stabilizing the 'biliary HCO3(-) umbrella' and thus preventing cholangiotoxicity of bile acids. The apical glycocalyx of a human cholangiocyte cell line and mouse liver sections were visualized by electron microscopy. FACS analysis was used to characterize the surface glycan profile of cultured human cholangiocytes. Using enzymatic digestion with neuraminidase the cholangiocyte glycocalyx was desialylated to test its protective function. Using lectin assays, we demonstrated that the main N-glycans in human and mouse cholangiocytes were sialylated biantennary structures, accompanied by high expression of the H-antigen (α1-2 fucose). Apical neuraminidase treatment induced desialylation without affecting cell viability, but lowered cholangiocellular resistance to bile acid-induced toxicity: both glycochenodeoxycholate and chenodeoxycholate (pKa ≥4), but not taurochenodeoxycholate (pKa <2), displayed cholangiotoxic effects after desialylation. A 24-hour reconstitution period allowed cholangiocytes to recover to a pretreatment bile salt susceptibility pattern. Experimental evidence indicates that an apical cholangiocyte glycocalyx with glycosylated mucins and other glycan-bearing membrane glycoproteins stabilizes the 'biliary HCO3(-) umbrella', thus aiding in the protection of human cholangiocytes against bile acid toxicity. 2015 S. Karger AG, Basel.

Effect of phospholipids and their molecular species on cholesterol solubility and nucleation in human and model biles.

PubMed Central

Halpern, Z; Moshkowitz, M; Laufer, H; Peled, Y; Gilat, T

1993-01-01

Much research in the pathophysiology of gall stones has been devoted to various molecular species of bile salts. Recent findings have shown the importance of phospholipids in biliary pathophysiology. In the present study the addition of increasing doses of egg lecithin to human and model biles progressively prolonged the nucleation time. Concurrently biliary cholesterol was shifted from the vesicular to the non-vesicular carrier(s) while the cholesterol/phospholipid ratio of the remaining vesicles was progressively lowered. Model bile solutions of identical lipid concentration were prepared using phosphatidylcholine, phosphatidylserine, and phosphatidylethanolamine as the only phospholipid. With phosphatidylethanolamine most of the cholesterol was shifted to the vesicular carrier while phosphatidylserine shifted most of the cholesterol to the non-vesicular carrier(s). With phosphatidylcholine the cholesterol was distributed in both carriers. Phosphatidyl choline species composed of various acyl fatty acids in the sn-1 and sn-2 positions were used as the sole phospholipid in otherwise identical model bile solutions. With palmitic acid in the sn-1 position and arachidonic acid in the sn-2 position most of the cholesterol was found in the non-vesicular carrier. When stearic acid was used in sn-2 position instead of arachidonic acid most of the cholesterol was found in the vesicular carrier. These and other variations in phospholipid molecular species shifted cholesterol among its carriers and also modified the nucleation time of model biles. Most of these effects were also found upon addition of the various phospholipid species to human biles. These findings show the importance of phospholipid species in biliary pathophysiology and may be useful when trying to manipulate cholesterol carriers and solubility in bile. PMID:8432440

Restoration of enterohepatic bile acid pathways in pregnant mice following short term activation of Fxr by GW4064

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moscovitz, Jamie E.; Kong, Bo; Buckley, Kyle

The farnesoid X receptor (Fxr) controls bile acid homeostasis by coordinately regulating the expression of synthesizing enzymes (Cyp7a1, Cyp8b1), conjugating enzymes (Bal, Baat) and transporters in the ileum (Asbt, Ostα/β) and liver (Ntcp, Bsep, Ostβ). Transcriptional regulation by Fxr can be direct, or through the ileal Fgf15/FGF19 and hepatic Shp pathways. Circulating bile acids are increased during pregnancy due to hormone-mediated disruption of Fxr signaling. While this adaptation enhances lipid absorption, elevated bile acids may predispose women to develop maternal cholestasis. The objective of this study was to determine whether short-term treatment of pregnant mice with GW4064 (a potent FXRmore » agonist) restores Fxr signaling to the level observed in virgin mice. Plasma, liver and ilea were collected from virgin and pregnant mice administered vehicle or GW4064 by oral gavage. Treatment of pregnant mice with GW4064 induced ileal Fgf15, Shp and Ostα/β mRNAs, and restored hepatic Shp, Bal, Ntcp, and Bsep back to vehicle-treated virgin levels. Pregnant mice exhibited 2.5-fold increase in Cyp7a1 mRNA compared to virgin controls, which was reduced by GW4064. Similarly treatment of mouse primary hepatocytes with plasma isolated from pregnant mice induced Cyp7a1 mRNA by nearly 3-fold as compared to virgin plasma, which could be attenuated by co-treatment with either GW4064 or recombinant FGF19 protein. Collectively, these data reveal that repressed activity of intestinal and hepatic Fxr in pregnancy, as previously demonstrated, may be restored by pharmacological activation. This study provides the basis for a novel approach to restore bile acid homeostasis in patients with maternal cholestasis. - Highlights: • Ileal bile acid pathways are altered in pregnancy in an Fxr-dependent manner. • Ileal Fxr/Fgf contributes to changes in hepatic bile acid synthesis and transport. • Treatment of pregnant mice with an Fxr agonist restores bile acid homeostasis.« less

Alisol B 23-acetate protects against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes involved in bile acid homeostasis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Qiang; Chen, Xin-li; Wang, Chang-yuan

2015-03-15

Intrahepatic cholestasis is a clinical syndrome with systemic and intrahepatic accumulation of excessive toxic bile acids that ultimately cause hepatobiliary injury. Appropriate regulation of bile acids in hepatocytes is critically important for protection against liver injury. In the present study, we characterized the protective effect of alisol B 23-acetate (AB23A), a natural triterpenoid, on alpha-naphthylisothiocyanate (ANIT)-induced liver injury and intrahepatic cholestasis in mice and further elucidated the mechanisms in vivo and in vitro. AB23A treatment dose-dependently protected against liver injury induced by ANIT through reducing hepatic uptake and increasing efflux of bile acid via down-regulation of hepatic uptake transporters (Ntcp)more » and up-regulation of efflux transporter (Bsep, Mrp2 and Mdr2) expression. Furthermore, AB23A reduced bile acid synthesis through repressing Cyp7a1 and Cyp8b1, increased bile acid conjugation through inducing Bal, Baat and bile acid metabolism through an induction in gene expression of Sult2a1. We further demonstrate the involvement of farnesoid X receptor (FXR) in the hepatoprotective effect of AB23A. The changes in transporters and enzymes, as well as ameliorative liver histology in AB23A-treated mice were abrogated by FXR antagonist guggulsterone in vivo. In vitro evidences also directly demonstrated the effect of AB23A on FXR activation in a dose-dependent manner using luciferase reporter assay in HepG2 cells. In conclusion, AB23A produces protective effect against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes. - Highlights: • AB23A has at least three roles in protection against ANIT-induced liver injury. • AB23A decreases Ntcp, and increases Bsep, Mrp2 and Mdr2 expression. • AB23A represses Cyp7a1 and Cyp8b1 through inducing Shp and Fgf15 expression. • AB23A increases bile acid metabolism through inducing Sult2a1 expression. • FXR activation is involved in the hepatoprotective effect of AB23A.« less

Unraveling the impact of hydroxylation on interactions of bile acid cationic lipids with model membranes by in-depth calorimetry studies.

PubMed

Singh, Manish; Bajaj, Avinash

2014-09-28

We used eight bile acid cationic lipids differing in the number of hydroxyl groups and performed in-depth differential scanning calorimetry studies on model membranes doped with different percentages of these cationic bile acids. These studies revealed that the number and positioning of free hydroxyl groups on bile acids modulate the phase transition and co-operativity of membranes. Lithocholic acid based cationic lipids having no free hydroxyl groups gel well with dipalmitoylphosphatidylcholine (DPPC) membranes. Chenodeoxycholic acid lipids having one free hydroxyl group at the 7'-carbon position disrupt the membranes and lower their co-operativity. Deoxycholic acid and cholic acid based cationic lipids have free hydroxyl groups at the 12'-carbon position, and at 7'- and 12'-carbon positions respectively. Doping of these lipids at high concentrations increases the co-operativity of membranes suggesting that these lipids might induce self-assembly in DPPC membranes. These different modes of interactions between cationic lipids and model membranes would help in future for exploring their use in DNA/drug delivery.

Assessment of ileal function by abdominal counting of the retention of a gamma emitting bile acid analogue.

PubMed Central

Thaysen, E H; Orholm, M; Arnfred, T; Carl, J; Rødbro, P

1982-01-01

In eight patients without gastrointestinal complaints and 30 patients with various gastrointestinal disorders ileal bile acid conservation was assessed by oral administration of 75Se 23-selena-25-homocholic acid (SeHCAT) followed by abdominal gamma counting (SeHCAT-test). The results of the test correlated fairly well with the clinical features and with the [1-14C]-cholylglycine breath test including faecal 14C measurements (breath test). Of the two bile acid absorption tests the new is perhaps the more sensitive and is the one most easily performed. PMID:7117906

The utility of 5-aminolevulinic acid-mediated photodynamic diagnosis in the detection of intraoperative bile leakage.

PubMed

Inoue, Yoshihiro; Imai, Yoshiro; Fujii, Kensuke; Hirokawa, Fumitoshi; Hayashi, Michihiro; Uchiyama, Kazuhisa

2017-06-01

The purpose of this retrospective study was to evaluate the utility of the new intraoperative bile leakage test as a preventive measure of postoperative bile leakage. 737 patients were retrospectively analyzed with respect to the management of intra- and post-operative bile leakage. Nine (8.3%) of 109 patients evaluated using conventional white light fluorescent imaging were recognized as having intra-operative bile leakage. However, performance of 5-aminolevulinic acid (5-ALA)-mediated PDD detected bile leakage intraoperatively not only in these 9 patients, but also in an additional 6 patients, such that 'red fluorescence' at the cut surface of the liver, was visualized in a total of 15 patients. The postoperative courses of most patients were uneventful, and postoperative bile leakages occurred in only one (0.9%) patient. 5-ALA fluorescence imaging may be needed to prevent postoperative bile leakage in patients at high risk for this surgical complication after hepatic resection. Copyright © 2016 Elsevier Inc. All rights reserved.

Bile acid sequestrants for cholesterol

MedlinePlus

... ency/patientinstructions/000787.htm Bile acid sequestrants for cholesterol To use the sharing features on this page, ... are medicines that help lower your LDL (bad) cholesterol . Too much cholesterol in your blood can stick ...

Feeding of the water extract from Ganoderma lingzhi to rats modulates secondary bile acids, intestinal microflora, mucins, and propionate important to colon cancer.

PubMed

Yang, Yongshou; Nirmagustina, Dwi Eva; Kumrungsee, Thanutchaporn; Okazaki, Yukako; Tomotake, Hiroyuki; Kato, Norihisa

2017-09-01

Consumption of reishi mushroom has been reported to prevent colon carcinogenesis in rodents, although the underlying mechanisms remain unclear. To investigate this effect, rats were fed a high-fat diet supplemented with 5% water extract from either the reishi mushroom (Ganoderma lingzhi) (WGL) or the auto-digested reishi G. lingzhi (AWGL) for three weeks. Both extracts markedly reduced fecal secondary bile acids, such as lithocholic acid and deoxycholic acid (colon carcinogens). These extracts reduced the numbers of Clostridium coccoides and Clostridium leptum (secondary bile acids-producing bacteria) in a per g of cecal digesta. Fecal mucins and cecal propionate were significantly elevated by both extracts, and fecal IgA was significantly elevated by WGL, but not by AWGL. These results suggest that the reishi extracts have an impact on colon luminal health by modulating secondary bile acids, microflora, mucins, and propionate that related to colon cancer.

Periodic variation in bile acids controls circadian changes in uric acid via regulation of xanthine oxidase by the orphan nuclear receptor PPARα.

PubMed

Kanemitsu, Takumi; Tsurudome, Yuya; Kusunose, Naoki; Oda, Masayuki; Matsunaga, Naoya; Koyanagi, Satoru; Ohdo, Shigehiro

2017-12-29

Xanthine oxidase (XOD), also known as xanthine dehydrogenase, is a rate-limiting enzyme in purine nucleotide degradation, which produces uric acid. Uric acid concentrations in the blood and liver exhibit circadian oscillations in both humans and rodents; however, the underlying mechanisms remain unclear. Here, we demonstrate that XOD expression and enzymatic activity exhibit circadian oscillations in the mouse liver. We found that the orphan nuclear receptor peroxisome proliferator-activated receptor-α (PPARα) transcriptionally activated the mouse XOD gene and that bile acids suppressed XOD transactivation. The synthesis of bile acids is known to be under the control of the circadian clock, and we observed that the time-dependent accumulation of bile acids in hepatic cells interfered with the recruitment of the co-transcriptional activator p300 to PPARα, thereby repressing XOD expression. This time-dependent suppression of PPARα-mediated transactivation by bile acids caused an oscillation in the hepatic expression of XOD, which, in turn, led to circadian alterations in uric acid production. Finally, we also demonstrated that the anti-hyperuricemic effect of the XOD inhibitor febuxostat was enhanced by administering it at the time of day before hepatic XOD activity increased. These results suggest an underlying mechanism for the circadian alterations in uric acid production and also underscore the importance of selecting an appropriate time of day for administering XOD inhibitors. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

The solute carrier family 10 (SLC10): beyond bile acid transport

PubMed Central

da Silva, Tatiana Claro; Polli, James E.; Swaan, Peter W.

2012-01-01

The solute carrier (SLC) family 10 (SLC10) comprises influx transporters of bile acids, steroidal hormones, various drugs, and several other substrates. Because the seminal transporters of this family, namely, sodium/taurocholate cotransporting polypeptide (NTCP; SLC10A1) and the apical sodium-dependent bile acid transporter (ASBT; SLC10A2), were primarily bile acid transporters, the term “sodium bile salt cotransporting family” was used for the SLC10 family. However, this notion became obsolete with the finding of other SLC10 members that do not transport bile acids. For example, the sodium-dependent organic anion transporter (SOAT; SLC10A6) transports primarily sulfated steroids. Moreover, NTCP was shown to also transport steroids and xenobiotics, including HMG-CoA inhibitors (statins). The SLC10 family contains four additional members, namely, P3 (SLC10A3; SLC10A3), P4 (SLC10A4; SLC10A4), P5 (SLC10A5; SLC10A5) and SLC10A7 (SLC10A7), several of which were unknown or considered hypothetical until approximately a decade ago. While their substrate specificity remains undetermined, great progress has been made towards their characterization in recent years. SLC10A4 may participate in vesicular storage or exocytosis of neurotransmitters or mastocyte mediators, whereas SLC10A5 and SLC10A7 may be involved in solute transport and SLC10A3 may have a role as a housekeeping protein. Finally, the newly found role of bile acids in glucose and energy homeostasis, via the TGR5 receptor, sheds new light on the clinical relevance of ASBT and NTCP. The present mini-review provides a brief summary of recent progress on members of the SLC10 family. PMID:23506869

Farnesoid X Receptor Agonist Treatment Alters Bile Acid Metabolism but Exacerbates Liver Damage in a Piglet Model of Short-Bowel Syndrome.

PubMed

Pereira-Fantini, Prue M; Lapthorne, Susan; Gahan, Cormac G M; Joyce, Susan A; Charles, Jenny; Fuller, Peter J; Bines, Julie E

2017-07-01

Options for the prevention of short-bowel syndrome-associated liver disease (SBS-ALDs) are limited and often ineffective. The farnesoid X receptor (FXR) is a newly emerging pharmaceutical target and FXR agonists have been shown to ameliorate cholestasis and metabolic disorders. The aim of this study was to assess the efficacy of obeticholic acid (OCA) treatment in preventing SBS-ALDs. Piglets underwent 75% small-bowel resection (SBS) or sham surgery (sham) and were assigned to either a daily dose of OCA (2.4 mg/kg/day) or were untreated. Clinical measures included weight gain and stool studies. Histologic features were assessed. Ultraperformance liquid chromatography tandem mass spectrometry was used to determine bile acid composition in end point bile and portal serum samples. Gene expression of key FXR targets was assessed in intestinal and hepatic tissues via quantitative polymerase chain reaction. OCA-treated SBS piglets showed decreased stool fat and altered liver histology when compared with nontreated SBS piglets. OCA prevented SBS-associated taurine depletion, however, further analysis of bile and portal serum samples indicated that OCA did not prevent SBS-associated alterations in bile acid composition. The expression of FXR target genes involved in bile acid transport and synthesis increased within the liver of SBS piglets after OCA administration whereas, paradoxically, intestinal expression of FXR target genes were decreased by OCA administration. Administration of OCA in SBS reduced fat malabsorption and altered bile acid composition, but did not prevent the development of SBS-ALDs. We postulate that extensive small resection impacts the ability of the remnant intestine to respond to FXR activation.

Effect of ursodeoxycholic acid treatment on ileal absorption of bile acids in man as determined by the SeHCAT test.

PubMed

Eusufzai, S; Ericsson, S; Cederlund, T; Einarsson, K; Angelin, B

1991-09-01

The effects of urodeoxycholic acid on ileal absorption of bile acids and on serum bile acid and lipoprotein concentrations were studied. Eight healthy subjects were investigated. The gamma emitting bile acid analogue, SeHCAT, was given orally and its fractional catabolic rate and seven day retention were assessed by repeated external counting over the upper abdomen during the next seven days. Ursodeoxycholic acid was then given orally at a dose of 15 mg/kg/day for three weeks and the study was repeated during treatment. The fractional catabolic rate increased by 64% (mean (SD), 0.333 (0.159) v 0.203 (0.061)/day; p less than 0.05) and seven day retention decreased by 44% (15(10) v 27(10)%, p less than 0.001), indicating bile acid malabsorption. Total serum cholesterol fell from 5.79 (1.22) to 5.50 (1.18) mmol/l (p = 0.05), while serum ursodeoxycholic acid increased 22 fold (7.87 (2.67) v 0.34 (0.24) mumol/l, p less than 0.001). Five of the subjects continued taking 30 mg/kg/day of ursodeoxycholic acid for one week and showed an increase in fractional catabolic rate of 81% (0.300 (0.091) v 0.166 (0.037)/day; p less than 0.05) and a fall in seven day retention of 50% (16 (12) v 32 (8)%, p less than 0.01). There were significant reductions in total cholesterol (5.36 (1.71) v 6.08 (1.47) mmol/l; p less than 0.05) and low density lipoprotein cholesterol (3.70 (1.33) v 4.58 (1.16) mmol/l; p less than 0.05). The results support the concept tht ursodeoxycholic acid treatment interferes with the absorption of endogenous bile acids, and emphasise the beneficial effects of this treatment of lipoprotein concentrations in man.

Effect of ursodeoxycholic acid treatment on ileal absorption of bile acids in man as determined by the SeHCAT test.

PubMed Central

Eusufzai, S; Ericsson, S; Cederlund, T; Einarsson, K; Angelin, B

1991-01-01

The effects of urodeoxycholic acid on ileal absorption of bile acids and on serum bile acid and lipoprotein concentrations were studied. Eight healthy subjects were investigated. The gamma emitting bile acid analogue, SeHCAT, was given orally and its fractional catabolic rate and seven day retention were assessed by repeated external counting over the upper abdomen during the next seven days. Ursodeoxycholic acid was then given orally at a dose of 15 mg/kg/day for three weeks and the study was repeated during treatment. The fractional catabolic rate increased by 64% (mean (SD), 0.333 (0.159) v 0.203 (0.061)/day; p less than 0.05) and seven day retention decreased by 44% (15(10) v 27(10)%, p less than 0.001), indicating bile acid malabsorption. Total serum cholesterol fell from 5.79 (1.22) to 5.50 (1.18) mmol/l (p = 0.05), while serum ursodeoxycholic acid increased 22 fold (7.87 (2.67) v 0.34 (0.24) mumol/l, p less than 0.001). Five of the subjects continued taking 30 mg/kg/day of ursodeoxycholic acid for one week and showed an increase in fractional catabolic rate of 81% (0.300 (0.091) v 0.166 (0.037)/day; p less than 0.05) and a fall in seven day retention of 50% (16 (12) v 32 (8)%, p less than 0.01). There were significant reductions in total cholesterol (5.36 (1.71) v 6.08 (1.47) mmol/l; p less than 0.05) and low density lipoprotein cholesterol (3.70 (1.33) v 4.58 (1.16) mmol/l; p less than 0.05). The results support the concept tht ursodeoxycholic acid treatment interferes with the absorption of endogenous bile acids, and emphasise the beneficial effects of this treatment of lipoprotein concentrations in man. PMID:1916489

Biliary excretion of pravastatin and taurocholate in rats with bile salt export pump (Bsep) impairment.

PubMed

Cheng, Yaofeng; Freeden, Chris; Zhang, Yueping; Abraham, Pamela; Shen, Hong; Wescott, Debra; Humphreys, W Griffith; Gan, Jinping; Lai, Yurong

2016-07-01

The bile salt export pump (BSEP) is expressed on the canalicular membrane of hepatocytes regulating liver bile salt excretion, and impairment of BSEP function may lead to cholestasis in humans. This study explored drug biliary excretion, as well as serum chemistry, individual bile acid concentrations and liver transporter expressions, in the SAGE Bsep knockout (KO) rat model. It was observed that the Bsep protein in KO rats was decreased to 15% of that in the wild type (WT), as quantified using LC-MS/MS. While the levels of Ntcp and Mrp2 were not significantly altered, Mrp3 expression increased and Oatp1a1 decreased in KO animals. Compared with the WT rats, the KO rats had similar serum chemistry and showed normal liver transaminases. Although the total plasma bile salts and bile flow were not significantly changed in Bsep KO rats, individual bile acids in plasma and liver demonstrated variable changes, indicating the impact of Bsep KO. Following an intravenous dose of deuterium labeled taurocholic acid (D4-TCA, 2 mg/kg), the D4-TCA plasma exposure was higher and bile excretion was delayed by approximately 0.5 h in the KO rats. No differences were observed for the pravastatin plasma concentration-time profile or the biliary excretion after intravenous administration (1 mg/kg). Collectively, the results revealed that these rats have significantly lower Bsep expression, therefore affecting the biliary excretion of endogenous bile acids and Bsep substrates. However, these rats are able to maintain a relatively normal liver function through the remaining Bsep protein and via the regulation of other transporters. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

[The clinical importance of physiopathological studies of the bile salts performed using the gamma-emitting bile acid SeHCAT].

PubMed

Ferraris, R; Fracchia, M; Galatola, G

1992-01-01

The availability of the gamma-labelled bile acid 75SeHCAT, that allows a non-invasive assessment of the enterohepatic circulation of bile acids, has prompted in the last 10 years the implementation of several studies involving wide series of normal subjects and patients with various organic and functional bowel disorders. The clinical indications for performing a SeHCAT test have been clearly defined: the test can identify with high accuracy, in the setting of the irritable bowel syndrome, the patients with bile acid malabsorption that can be confidently and successfully treated with cholestyramine; it can also assess whether, and to what extent, the diarrhoea presenting in patients with intestinal organic disorders is due to bile acid malabsorption, permitting an optimal therapeutic strategy to be designed. The parameters of the hepatic handling of SeHCAT after bolus intravenous administration have been characterized in normals, and studies on various chronic hepatic disorders are now in progress. Interesting results are emerging from studies performed in patients with chronic non-obstructive cholestatic disease, where a specific defect in the excretion rate of SeHCAT is present: these studies may cast more light on the abnormalities of bile secretion and on the mechanism of action of drugs used to treat this condition, forming the rationale for the use of intravenous SeHCAT for hepatobiliary dynamic scintigraphy as a sophisticated liver function test. In conclusion, the SeHCAT test has become an important diagnostic tool for the gastroenterologist studying the diarrhoea, and awaits more studies to be used also by the hepatologist. The relatively long physical half-life of 75Se (180 days), preventing a wider use of the test, could theoretically be overcome by the synthesis of a similar gamma-labelled bile acid with a shorter half-life.

Human beta-glucuronidase. Measurement of its activity in gallbladder bile devoid of intrinsic interference.

PubMed

Ho, Y C; Ho, K J

1988-04-01

Our purpose is to develop a standard method for preparing the bile for beta-glucuronidase determination by removal of bile acids and conjugated bilirubin which interfere with its activity. The bile acids and conjugated bilirubin in their purified solutions and in the diluted gallbladder biles could be extracted completely with cholestyramine in powder form or tetrahexylammonium chloride (THAC) in chloroform or ethyl acetate. The enzyme was, however, partially precipitated with cholestyramine and denatured by chloroform but not by ethyl acetate. A standard procedure, therefore, includes extraction of the diluted gallbladder bile with THAC in ethyl acetate, followed by determination of the maximal velocity (Vmax) of the enzyme by a kinetic method employing phenolphthalein glucuronide as the substrate. The average Vmax of beta-glucuronidase in the 20 normal gallbladder biles was 165 +/- 86 nmol/min/ml (mean +/- SD), a 23.5-fold increase over the activity before extraction. The measured activity represented the true activity of the enzyme in the bile for recovery of activity of the enzyme added to the bile was practically complete.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyd, G.S.; Merrick, M.V.; Monks, R.

Four selenium-labeled free bile acids and four selenium-labeled conjugated bile acids, labeled with Se-75 at the C-19, C-22, C-23, or C-24 position, have been synthesized and their absorption and excretion compared with that of (24-/sup 14/C)cholic acid, following both oral and intravenous administration. All but one of the compounds is absorbed and excreted in bile to a significant extent. One compound, SeHCAT, has been selected for particular study. It is quantitatively absorbed from the gut at the same rate as cholic acid, and both are excreted into the bile at the same rate. It remains almost entirely confined to themore » enterohepatic circulation (the gut, liver, and biliary tree) and excretion is exclusively fecal. Such a compound offers the possibility of a simple, novel, and aesthetically acceptalbe method investigating small-bowel disease.« less

Fecal bile acids of black-footed ferrets

USGS Publications Warehouse

Richardson, Louise; Johnson, M.K.; Clark, T.W.; Schroder, M.H.

1986-01-01

Fecal bile acid characteristics have been used to identify scats to species of origin. Fecal bile acids in scats from 20 known black-footed ferrets ( Mustela nigripes ), 7 other known small carnivores, and 72 of unknown origin were analyzed to determine if this procedure could be used as a tool to verify ferret presence in an area. Seventeen ferret scats were suitable for analysis and had a mean fecal bile acid index of 156 ± 9. This was significantly different from mean indices for the other carnivores; however, substantial overlap among confidence intervals occurred for badgers, kit foxes, and especially long-tailed weasels. We conclude this method is not useful for making positive identifications if individual ferret scats and suggest that we may be able to definitively identify individual scats with reasonable confidence by using gas-liquid chromatography.

Determination and importance of temperature dependence of retention coefficient (RPHPLC) in QSAR model of nitrazepams' partition coefficient in bile acid micelles.

PubMed

Posa, Mihalj; Pilipović, Ana; Lalić, Mladena; Popović, Jovan

2011-02-15

Linear dependence between temperature (t) and retention coefficient (k, reversed phase HPLC) of bile acids is obtained. Parameters (a, intercept and b, slope) of the linear function k=f(t) highly correlate with bile acids' structures. Investigated bile acids form linear congeneric groups on a principal component (calculated from k=f(t)) score plot that are in accordance with conformations of the hydroxyl and oxo groups in a bile acid steroid skeleton. Partition coefficient (K(p)) of nitrazepam in bile acids' micelles is investigated. Nitrazepam molecules incorporated in micelles show modified bioavailability (depo effect, higher permeability, etc.). Using multiple linear regression method QSAR models of nitrazepams' partition coefficient, K(p) are derived on the temperatures of 25°C and 37°C. For deriving linear regression models on both temperatures experimentally obtained lipophilicity parameters are included (PC1 from data k=f(t)) and in silico descriptors of the shape of a molecule while on the higher temperature molecular polarisation is introduced. This indicates the fact that the incorporation mechanism of nitrazepam in BA micelles changes on the higher temperatures. QSAR models are derived using partial least squares method as well. Experimental parameters k=f(t) are shown to be significant predictive variables. Both QSAR models are validated using cross validation and internal validation method. PLS models have slightly higher predictive capability than MLR models. Copyright © 2010 Elsevier B.V. All rights reserved.

Multilayer affinity adsorption of albumin on polymer brushes modified membranes in a continuous-flow system.

PubMed

Hu, Meng-Xin; Li, Xiang; Li, Ji-Nian; Huang, Jing-Jing; Ren, Ge-Rui

2018-02-23

Polymer brushes modified surfaces have been widely used for protein immobilization and isolation. Modification of membranes with polymer brushes increases the surface concentration of affinity ligands used for protein binding. Albumin is one of the transporting proteins and shows a high affinity to bile acids. In this work, the modified membranes with cholic acid-containing polymer brushes can be facilely prepared by the immobilization of cholic acid on the poly(2-hydroxyethyl methacrylate) grafted microporous polypropylene membranes (MPPMs) for affinity adsorption of albumin. ATR/FT-IR and X-ray photoelectron spectroscopy were used to characterize the chemical composition of the modified membranes. Water contact angle measurements were used to analyze the hydrophilic/hydrophobic properties of the membrane surface. The modified MPPMs show a high affinity to albumin and have little non-specific adsorption of hemoglobin. The dynamic binding capacity of albumin in the continous-flow system increases with the cycle number and feed rate as the binding degree of cholic acid is moderate. The highest binding capacity of affinity membranes is about 52.49 g/m 2 membrane, which is about 24 times more than the monolayer binding capacity. These results reveal proteins could be captured in multilayers by the polymer brushes containing affinity ligands similar to the polymer brushes containing ion-exchange groups, which open up the potential of the polymer brushes containing affinity ligands in protein or another components separation. And the cholic acid containing polymer brushes modified membranes has the promising potential for albumin separation and purification rapidly from serum or fermented solution in medical diagnosis and bioseparation. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of the type of dietary fat on biliary lipid composition and bile lithogenicity in humans with cholesterol gallstone disease.

PubMed

Yago, María Dolores; González, Victoria; Serrano, Pilar; Calpena, Rafael; Martínez, María Alba; Martínez-Victoria, Emilio; Mañas, Mariano

2005-03-01

The effect of the type of dietary fat on bile lipids and lithogenicity is unclear. This study compared the effects of two dietary oils that differed in fatty acid profile on biliary lipid composition in humans. Female patients who had cholesterol gallstones and were scheduled for elective cholecystectomy were studied. For 30 d before surgery, subjects were kept on diets that contained olive oil (olive oil group, n = 9) or sunflower oil (sunflower oil group, n = 9) as the main source of fat. Gallbladder bile and stones were sampled at surgery. After cholecystectomy, duodenal samples were collected by nasoduodenal intubation during fasting and after administration of mixed liquid meals that included the corresponding dietary oil. Duodenal and gallbladder bile samples were analyzed for cholesterol, phospholipids, and total bile acids by established methods. Individual bile acid conjugates in gallbladder bile were measured by high-performance liquid chromatography. Gallstones were analyzed by semiquantitative polarizing light microscopy. Despite marked differences in the absolute concentration of biliary lipids and total lipid content, manipulation of dietary fat ingestion did not influence the cholesterol saturation or the profile of individual bile acids in gallbladder bile obtained from patients who had gallstones. All but one subject had mixed cholesterol stones. A cholesterol saturation index of hepatic bile in fasted cholecystectomized patients was similar in both dietary groups and indicative of supersaturation. In response to the test meal, the cholesterol saturation index decreased significantly in patients given the olive oil diet, reaching values lower than one at 120 min postprandially. In contrast, hepatic bile secreted by patients who consumed sunflower oil appeared supersaturated (cholesterol saturation index >1.5) throughout the experiment. Our results suggest that the type of dietary fat habitually consumed can influence bile composition in humans. In gallbladder, this influence was noted in the presence of more concentrated bile in the olive oil group. However, this was not translated into a modification of cholesterol saturation, which is likely due to the fact that cholesterol gallstones were present by the time the dietary intervention started. The finding that a typical postprandial variation in hepatic bile lithogenicity occurred only in olive oil patients was revealing. While keeping in mind the methodologic limitations of this part of the study, some gastrointestinal and metabolic mechanisms for this effect are discussed.

Modulation of the Unfolded Protein Response by Tauroursodeoxycholic Acid Counteracts Apoptotic Cell Death and Fibrosis in a Mouse Model for Secondary Biliary Liver Fibrosis

PubMed Central

Paridaens, Annelies; Raevens, Sarah; Devisscher, Lindsey; Bogaerts, Eliene; Verhelst, Xavier; Hoorens, Anne; van Vlierberghe, Hans; Van Grunsven, Leo A.; Geerts, Anja; Colle, Isabelle

2017-01-01

The role of endoplasmic reticulum stress and the unfolded protein response (UPR) in cholestatic liver disease and fibrosis is not fully unraveled. Tauroursodeoxycholic acid (TUDCA), a hydrophilic bile acid, has been shown to reduce endoplasmic reticulum (ER) stress and counteract apoptosis in different pathologies. We aimed to investigate the therapeutic potential of TUDCA in experimental secondary biliary liver fibrosis in mice, induced by common bile duct ligation. The kinetics of the hepatic UPR and apoptosis during the development of biliary fibrosis was studied by measuring markers at six different timepoints post-surgery by qPCR and Western blot. Next, we investigated the therapeutic potential of TUDCA, 10 mg/kg/day in drinking water, on liver damage (AST/ALT levels) and fibrosis (Sirius red-staining), in both a preventive and therapeutic setting. Common bile duct ligation resulted in the increased protein expression of CCAAT/enhancer-binding protein homologous protein (CHOP) at all timepoints, along with upregulation of pro-apoptotic caspase 3 and 12, tumor necrosis factor receptor superfamily, member 1A (TNFRsf1a) and Fas-Associated protein with Death Domain (FADD) expression. Treatment with TUDCA led to a significant reduction of liver fibrosis, accompanied by a slight reduction of liver damage, decreased hepatic protein expression of CHOP and reduced gene and protein expression of pro-apoptotic markers. These data indicate that TUDCA exerts a beneficial effect on liver fibrosis in a model of cholestatic liver disease, and suggest that this effect might, at least in part, be attributed to decreased hepatic UPR signaling and apoptotic cell death. PMID:28117681

Promoter variant -204A > C of the cholesterol 7α-hydroxylase gene: association with response to plant sterols in humans and increased transcriptional activity in transfected HepG2 cells.

PubMed

De Castro-Orós, Isabel; Pampín, Sandra; Cofán, Montserrat; Mozas, Pilar; Pintó, Xavier; Salas-Salvadó, Jordi; Rodríguez-Rey, Jose C; Ros, Emilio; Civeira, Fernando; Pocoví, Miguel

2011-04-01

The bile acid pool influences intestinal cholesterol absorption because this process is strictly dependent on micellar solubilization, which is disrupted by plant sterols (PS). Plasma lipid variation relates to promoter variant -204A > C (rs3808607) of the CYP7A1 gene encoding for 7α-hydroxylase, an enzyme for bile acid synthesis. We hypothesized that this polymorphism would be associated with variability in lipid responses to PS. We investigated 67 subjects (31 AA and 36 AC + CC) with lipid responses to PS documented in two studies. To assess the functionality of the -204A > C variant, electrophoretic mobility gel shift assays were performed and luciferase reporter plasmids containing the promoter were transfected into HepG2 cells. Compared to AA-subjects, C-carriers showed significantly higher adjusted mean reductions in total cholesterol (0.14 versus 0.43 mmol/L, P = 0.042) and increases in lathosterol-to-cholesterol ratios (0.10 versus 0.75, P = 0.013). The C-construct caused a 78% promoter activity increase and gel-shift assays showed lower affinity for nuclear transcription factors, while in silico experiments predicted a binding site for inhibitory nuclear factors RXR-CAR. Results suggest that promoter -204A > C variant is associated with enhanced CYP7A1 activity. Increased intestinal bile acids and ensuing more efficient cholesterol absorption might explain why C-allele carriers show enhanced cholesterol lowering and increased feedback cholesterol synthesis to PS intervention. Copyright © 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

The effects of micronutrient deficiencies on bacterial species from the human gut microbiota

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hibberd, Matthew C.; Wu, Meng; Rodionov, Dmitry A.

Micronutrient deficiencies afflict two billion people. And while the impact of these imbalances on host biology has been studied extensively, much less is known about their effects on the developing or adult gut microbiota. Thus, we established a community of 44 cultured, sequenced human gut-derived bacterial species in gnotobiotic mice and fed the animals a defined, micronutrient-sufficient diet, followed by a derivative diet devoid of vitamin A, folate, iron or zinc, followed by return to the sufficient diet. Acute vitamin A deficiency had the largest effect on community structure and meta-transcriptome, with Bacteroides vulgatus, a prominent responder, increasing its abundancemore » in the absence of vitamin A, and manifesting transcriptional changes involving various metabolic pathways. Applying retinol selection to a library of 30,300 B. vulgatus transposon mutants revealed that disruption of acrR abrogated retinol sensitivity. Genetic complementation studies, microbial RNA-Seq, and transcription factor binding assays disclosed that AcrR functions as a repressor of an adjacent AcrAB-TolC efflux system plus other members of its regulon. Retinol efflux measurements in wild-type, acrR-mutant, and complemented acrR mutant strains, plus treatment with a pharmacologic inhibitor of the efflux system, revealed that AcrAB-TolC is a determinant of retinol and bile acid sensitivity. We associated acute vitamin A deficiency with altered bile acid metabolism in vivo, raising the possibility that retinol, bile acid metabolites, and AcrAB-TolC interact to influence the fitness of B. vulgatus and perhaps other microbiota members. This type of preclinical model can help develop mechanistic insights about and more effective treatment strategies for micronutrient deficiencies.« less

The effects of micronutrient deficiencies on bacterial species from the human gut microbiota.

PubMed

Hibberd, Matthew C; Wu, Meng; Rodionov, Dmitry A; Li, Xiaoqing; Cheng, Jiye; Griffin, Nicholas W; Barratt, Michael J; Giannone, Richard J; Hettich, Robert L; Osterman, Andrei L; Gordon, Jeffrey I

2017-05-17

Vitamin and mineral (micronutrient) deficiencies afflict 2 billion people. Although the impact of these imbalances on host biology has been studied extensively, much less is known about their effects on the gut microbiota of developing or adult humans. Therefore, we established a community of cultured, sequenced human gut-derived bacterial species in gnotobiotic mice and fed the animals a defined micronutrient-sufficient diet, followed by a derivative diet devoid of vitamin A, folate, iron, or zinc, followed by return to the sufficient diet. Acute vitamin A deficiency had the largest effect on bacterial community structure and metatranscriptome, with Bacteroides vulgatus, a prominent responder, increasing its abundance in the absence of vitamin A. Applying retinol selection to a library of 30,300 B. vulgatus transposon mutants revealed that disruption of acrR abrogated retinol sensitivity. Genetic complementation studies, microbial RNA sequencing, and transcription factor-binding assays disclosed that AcrR is a repressor of an adjacent AcrAB-TolC efflux system. Retinol efflux measurements in wild-type and acrR -mutant strains plus treatment with a pharmacologic inhibitor of the efflux system revealed that AcrAB-TolC is a determinant of retinol and bile acid sensitivity in B. vulgatus Acute vitamin A deficiency was associated with altered bile acid metabolism in vivo, raising the possibility that retinol, bile acid metabolites, and AcrAB-TolC interact to influence the fitness of B. vulgatus and perhaps other microbiota members. This type of preclinical model can help to develop mechanistic insights about the effects of, and more effective treatment strategies for micronutrient deficiencies. Copyright © 2017, American Association for the Advancement of Science.

Chemoprevention of esophageal adenocarcinoma in a rat model by ursodeoxycholic acid.

PubMed

Ojima, Eisuke; Fujimura, Takashi; Oyama, Katsunobu; Tsukada, Tomoya; Kinoshita, Jun; Miyashita, Tomoharu; Tajima, Hidehiro; Fushida, Sachio; Harada, Shin-ichi; Mukaisho, Ken-ichi; Hattori, Takanori; Ohta, Tetsuo

2015-08-01

Reflux of bile acid into the esophagus induces esophagitis, inflammation-stimulated hyperplasia, metaplasia such as Barrett's esophagus (BE), and esophageal adenocarcinoma (EAC). Caudal-type homeobox 2 (Cdx2) via nuclear factor (NF)-κB induced by bile acid is an important factor in the development of BE and EAC. In colorectal cancer, experimental data suggest a chemopreventive effect of ursodeoxycholic acid (UDCA). We hypothesized that UDCA may protect against the esophageal inflammation-metaplasia-carcinoma sequence by decreasing the overall proportion of the toxic bile acids. Wistar male rats that underwent a duodenoesophageal reflux procedure were divided into two groups. One group was given commercial chow (control group), and the other was given experimental chow containing UDCA (UDCA group). The animals were killed at 40 weeks after surgery, and their bile and esophagus were examined. In the UDCA group, the esophagitis was milder and the incidence of BE was significantly lower (p < 0.05) than in the control group, and EAC was not observed (p < 0.05). In analysis of the compartment of bile acid, UDCA was markedly increased in the UDCA group compared with the control group (32.7 ± 11.4 vs. 0.82 ± 0.33 mmol/L, p < 0.05) and cholic acid was decreased (32.7 ± 4.05 vs. 60.9 ± 8.26 mmol/L, p < 0.05). Expression intensity of Cdx2 and NF-κB was greater in the control group than in the UDCA group (p < 0.05). UDCA may be a chemopreventive agent against EAC by varying the bile acid composition.

Metformin interferes with bile acid homeostasis through AMPK-FXR crosstalk

PubMed Central

Lien, Fleur; Berthier, Alexandre; Bouchaert, Emmanuel; Gheeraert, Céline; Alexandre, Jeremy; Porez, Geoffrey; Prawitt, Janne; Dehondt, Hélène; Ploton, Maheul; Colin, Sophie; Lucas, Anthony; Patrice, Alexandre; Pattou, François; Diemer, Hélène; Van Dorsselaer, Alain; Rachez, Christophe; Kamilic, Jelena; Groen, Albert K.; Staels, Bart; Lefebvre, Philippe

2014-01-01

The nuclear bile acid receptor farnesoid X receptor (FXR) is an important transcriptional regulator of bile acid, lipid, and glucose metabolism. FXR is highly expressed in the liver and intestine and controls the synthesis and enterohepatic circulation of bile acids. However, little is known about FXR-associated proteins that contribute to metabolic regulation. Here, we performed a mass spectrometry–based search for FXR-interacting proteins in human hepatoma cells and identified AMPK as a coregulator of FXR. FXR interacted with the nutrient-sensitive kinase AMPK in the cytoplasm of target cells and was phosphorylated in its hinge domain. In cultured human and murine hepatocytes and enterocytes, pharmacological activation of AMPK inhibited FXR transcriptional activity and prevented FXR coactivator recruitment to promoters of FXR-regulated genes. Furthermore, treatment with AMPK activators, including the antidiabetic biguanide metformin, inhibited FXR agonist induction of FXR target genes in mouse liver and intestine. In a mouse model of intrahepatic cholestasis, metformin treatment induced FXR phosphorylation, perturbed bile acid homeostasis, and worsened liver injury. Together, our data indicate that AMPK directly phosphorylates and regulates FXR transcriptional activity to precipitate liver injury under conditions favoring cholestasis. PMID:24531544

Decreased hepatotoxic bile acid composition and altered synthesis in progressive human nonalcoholic fatty liver disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lake, April D.; Novak, Petr; Shipkova, Petia

2013-04-15

Bile acids (BAs) have many physiological roles and exhibit both toxic and protective influences within the liver. Alterations in the BA profile may be the result of disease induced liver injury. Nonalcoholic fatty liver disease (NAFLD) is a prevalent form of chronic liver disease characterized by the pathophysiological progression from simple steatosis to nonalcoholic steatohepatitis (NASH). The hypothesis of this study is that the ‘classical’ (neutral) and ‘alternative’ (acidic) BA synthesis pathways are altered together with hepatic BA composition during progression of human NAFLD. This study employed the use of transcriptomic and metabolomic assays to study the hepatic toxicologic BAmore » profile in progressive human NAFLD. Individual human liver samples diagnosed as normal, steatosis, and NASH were utilized in the assays. The transcriptomic analysis of 70 BA genes revealed an enrichment of downregulated BA metabolism and transcription factor/receptor genes in livers diagnosed as NASH. Increased mRNA expression of BAAT and CYP7B1 was observed in contrast to decreased CYP8B1 expression in NASH samples. The BA metabolomic profile of NASH livers exhibited an increase in taurine together with elevated levels of conjugated BA species, taurocholic acid (TCA) and taurodeoxycholic acid (TDCA). Conversely, cholic acid (CA) and glycodeoxycholic acid (GDCA) were decreased in NASH liver. These findings reveal a potential shift toward the alternative pathway of BA synthesis during NASH, mediated by increased mRNA and protein expression of CYP7B1. Overall, the transcriptomic changes of BA synthesis pathway enzymes together with altered hepatic BA composition signify an attempt by the liver to reduce hepatotoxicity during disease progression to NASH. - Highlights: ► Altered hepatic bile acid composition is observed in progressive NAFLD. ► Bile acid synthesis enzymes are transcriptionally altered in NASH livers. ► Increased levels of taurine and conjugated bile acids are observed in NASH. ► Hepatic bile acid synthesis shifts toward the alternative pathway in NASH.« less

Oral administration of oleanolic acid, isolated from Swertia mussotii Franch, attenuates liver injury, inflammation, and cholestasis in bile duct-ligated rats

PubMed Central

Chai, Jin; Du, Xiaohuang; Chen, Sheng; Feng, XinChan; Cheng, Ying; Zhang, Liangjun; Gao, Yu; Li, Shaoxue; He, Xiaochong; Wang, Rongquan; Zhou, Xiangdong; Yang, Yong; Luo, Weizao; Chen, Wensheng

2015-01-01

Background & aims: Oleanolic acid is abundantly distributed in Swertia mussotii Franch, a Chinese traditional herb for the treatment of jaundice. However, the hepatoprotective role of oleanolic acid in obstructive cholestasis and its underlying molecular mechanism are unclear. Methods: Normal rats and bile duct-ligated (BDL) rats were given oleanolic acid and serum biochemistry, bile salts, and pro-inflammatory factors were measured, as well as the expression levels of liver bile acid synthesis and detoxification enzymes, membrane transporters, nuclear receptors, and transcriptional factors. Results: Oral administration of oleanolic acid at 100 mg/kg did not cause rat liver injury. However, it significantly reduced the serum levels of alanine aminotransferase (ALT) on days 7 and 14, aspartate aminotransferase (AST) and TNF-α on day 14, and alkaline phosphatase (ALP) and IL-1β on days 3, 7, and 14 in the BDL rats. Furthermore, the serum levels of total bile acid (TBA) and bile acids, including CDCA, CA, DCA, and Tα/βMCA were significantly reduced by oleanolic acid on day 3 in the BDL rats. In addition, the expression levels of detoxification enzymes Cyp3a, Ugt2b, Sult2a1, Gsta1-2, and Gstm1-3, membrane transporters Mrp3, Mrp4, Ostβ, Mdr1, Mdr2, and Bsep, nuclear receptors Pxr, Vdr, Hnf4α, Rxrα, Rarα, Lxr, and Lrh-1, and transcriptional factors Nrf2, Hnf3β, and Ahr were significantly increased in oleanolic acid-treated rats. Conclusion: We demonstrated that the oral administration of oleanolic acid attenuates liver injury, inflammation, and cholestasis in BDL rats. The anti-cholestatic effect may be associated with the induction of hepatic detoxification enzymes and efflux transporters mediated by nuclear receptors and transcriptional factors. PMID:25932098

[Rapid identification of two new isomers in bear bile powder by LC-Q-TOF-MS combined with PCC oxidation].

PubMed

Jian, Long-Hai; Hu, Chun; Yu, Hong; Wang, Ke; Ji, Shen

2013-07-01

A rapid method of Liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) combined with pyridinium chlorochromate (PCC) oxidation has been developed to determine chemical structures of two novel isomers in bear bile powder. Derivatives of ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) were semi-synthesized by PCC oxidation, then were analyzed by LC-Q-TOF-MS. Separation was carried out on a reverse column with the mobile phase of acetonitrile-0.1% formic acid (45:55). The data of Q-TOF-MS was acquired by MS, MS/MS, positive and negative modes. Since UDCA and CDCA were stereochemical isomeric at an alcohol position, two oxidation products were same and have been confirmed by LC-Q-TOF-MS. Other two products were also determined based on the PCC oxidation theory. Samples of bear bile powder were dissolved by methanol and measured by LC-Q-TOF-MS. Two unknown peaks were found and identified by matching their retention times and accurate mass spectra ions with PCC oxidation productS. Finally, the structures of two new bile acids in bear bile powder were confirmed as 3alpha-hydroxy-7-oxo-5beta-cholanic acid, 7alpha-hydroxy-3-oxo-5beta-cholanic acid, respectively.

The role of an alginate suspension on pepsin and bile acids - key aggressors in the gastric refluxate. Does this have implications for the treatment of gastro-oesophageal reflux disease?

PubMed

Strugala, Vicki; Avis, Jeanine; Jolliffe, Ian G; Johnstone, Lesley M; Dettmar, Peter W

2009-08-01

During a reflux event the oesophagus is exposed to a heterogeneous mixture of gastric juice components. The role of non-acid components of the refluxate in causing damage to the oesophagus is now well established but no therapeutic option exists to address this. The role of Gaviscon Advance (GA), a raft-forming alginate suspension, in protecting the oesophagus from damage by pepsin and bile acids (aggressors) was investigated using a series of in-vitro models. GA was able to dose-dependently inhibit pepsin activity over and above the neutralisation effect of the formulation. This was evident against both protein and collagen substrates using two distinct colorimetric assays. GA was able to retard the diffusion of pepsin and multiple bile acids using a Franz cell model. Using the raft-forming mode of action GA was able to remove both pepsin and multiple bile acids from a simulated reflux event. There was capacity in the GA raft to accommodate aggressors from multiple reflux events. GA can specifically remove both pepsin and bile acids from the refluxate, limit their diffusion and affect enzymatic activity of pepsin. There is a role for GA to reduce the damaging potential of the refluxate and thus protect the oesophagus.

[Joint action of nitrofuran preparations and bile acids on bacteria of the genus Proteus].

PubMed

Sytnik, I A; Puzakova, E V

1975-01-01

Sensitivity of 25 fresh isolates of Proteus to some nitrofuran drugs most widely used in the clinical practice, such as furacillin, furagin, furazolidone and nitrofurantoin was studied. When the drugs were used in combination with some bile acids, i.e. desoxycholic, dehydrocholic, cholic and glycocholic acids, significant in vitro potentiation of the antibacterial activity of the nitrofurans against the isolates was observed. The combinations of the drugs with desoxycholic acid proved to be most effective. In the presence of this acid the bacteriostatic dose of the drugs decreased several thousand times. Combination of the nitrofurans with the other acids resulted in an increase in the antimicrobial activity amounting to several hundred times. The combinations of the drugs with the bile acids had not only bacteriostatic but also bactericidal effect.

Obeticholic Acid

MedlinePlus

... PBC; a type of liver disease that destroys bile ducts, which allows bile to stay in the liver and cause damage) ... agonists. It works by decreasing the production of bile in the liver and increasing the removal of ...

Bile Reflux

MedlinePlus

... medications. But there is little evidence pinpointing the effects of bile reflux in people. Unlike acid reflux, bile reflux usually can't be completely controlled by changes in diet or lifestyle. Treatment involves medications or, in severe cases, surgery. ...

Bilirubin and bile acids removal by haemoperfusion through synthetic resin "Persorb".

PubMed

Filip, K; Malý, J; Horký, J; Tlustáková, M; Kálal, J; Vrána, M

1990-01-01

A new type of styrene-divinylbenzene copolymer coated with polyhema was tested for biocompatibility and ability to remove bile acid, bilirubin, phenols and cholesterol in dogs with surgically induced biliary obstruction. After 4-hr hemoperfusion through a polypropylene column containing 325 g of resin, performed 7-10 days after the ligature of the cystic and common bile duct, the serum levels of bile acids, bilirubin, phenols and cholesterol decreased by 60.9 +/- 30.3% (p less than 0.001), 34.8 +/- 12.2% (p less than 0.001), 19.4 +/- 15.6% (p less than 0.001) and 15.3 +/- 4.2% (p less than 0.05), respectively. The procedure was well tolerated, no bleeding or other adverse reactions occurred. The average platelet count decreased by 19.4 +/- 15.6% (p less than 0.05). Hemoperfusion through the Czechoslovak resin coated with polyhema is safe and efficient for removal of bile acids and other protein-bound and lipid-soluble substances which accumulate in cholestatic syndromes and hepatic failure. Thus, it may play an important role in the treatment of such events as a method of artificial liver support.

Long-Term Ursodeoxycholic Acid Therapy Does Not Alter Lithocholic Acid Levels in Patients with Cystic Fibrosis with Associated Liver Disease.

PubMed

Colombo, Carla; Crosignani, Andrea; Alicandro, Gianfranco; Zhang, Wujuan; Biffi, Arianna; Motta, Valentina; Corti, Fabiola; Setchell, Kenneth D R

2016-10-01

To evaluate the fasting and postprandial serum bile acid composition in patients with cystic fibrosis-associated liver disease (CFLD) after chronic administration of ursodeoxycholic acid (UDCA) (20 mg/kg/day). The aim was to specifically focus on the extent of biotransformation of UDCA to its hepatotoxic metabolite, lithocholic acid, because of recent concerns regarding the safety of long-term, high-dose UDCA treatment for CFLD. Twenty patients with CFLD (median age 16 years, range: 2.4-35.0) prescribed UDCA therapy for at least 2 years were studied. Total and individual serum bile acids were measured by stable-isotope dilution mass spectrometry, in fasting and 2-hour postprandial samples taken during chronic UDCA (20 mg/kg/day) administration. During chronic UDCA administration (median duration 8 years, IQR: 6-16), UDCA became the predominant serum bile acid in all patients (median, IQR: 3.17, 1.25-5.56 μmol/L) and chenodeoxycholic acid concentrations were greater than cholic acid (1.86, 1.00-4.70 μmol/L vs 0.40, 0.24-2.71 μmol/L). The secondary bile acids, deoxycholate and lithocholate, were present in very low concentrations in fasted serum (<0.05 μmol/L). After UDCA administration, 2-hour postprandial concentrations of both UDCA and chenodeoxycholic acid significantly increased (P < .01), but no significant changes in serum lithocholic acid concentrations were observed. These data do not support recent suggestions that enhanced biotransformation of UDCA to the hepatotoxic secondary bile acid lithocholic occurs when patients with CFLD are treated with relatively high doses of UDCA. Copyright © 2016 Elsevier Inc. All rights reserved.

Bile acids deoxycholic acid and ursodeoxycholic acid differentially regulate human β-defensin-1 and -2 secretion by colonic epithelial cells.

PubMed

Lajczak, Natalia K; Saint-Criq, Vinciane; O'Dwyer, Aoife M; Perino, Alessia; Adorini, Luciano; Schoonjans, Kristina; Keely, Stephen J

2017-09-01

Bile acids and epithelial-derived human β-defensins (HβDs) are known to be important factors in the regulation of colonic mucosal barrier function and inflammation. We hypothesized that bile acids regulate colonic HβD expression and aimed to test this by investigating the effects of deoxycholic acid (DCA) and ursodeoxycholic acid on the expression and release of HβD1 and HβD2 from colonic epithelial cells and mucosal tissues. DCA (10-150 µM) stimulated the release of both HβD1 and HβD2 from epithelial cell monolayers and human colonic mucosal tissue in vitro In contrast, ursodeoxycholic acid (50-200 µM) inhibited both basal and DCA-induced defensin release. Effects of DCA were mimicked by the Takeda GPCR 5 agonist, INT-777 (50 μM), but not by the farnesoid X receptor agonist, GW4064 (10 μM). INT-777 also stimulated colonic HβD1 and HβD2 release from wild-type, but not Takeda GPCR 5 -/- , mice. DCA stimulated phosphorylation of the p65 subunit of NF-κB, an effect that was attenuated by ursodeoxycholic acid, whereas an NF-κB inhibitor, BMS-345541 (25 μM), inhibited DCA-induced HβD2, but not HβD1, release. We conclude that bile acids can differentially regulate colonic epithelial HβD expression and secretion and discuss the implications of our findings for intestinal health and disease.-Lajczak, N. K., Saint-Criq, V., O'Dwyer, A. M., Perino, A., Adorini, L., Schoonjans, K., Keely, S. J. Bile acids deoxycholic acid and ursodeoxycholic acid differentially regulate human β-defensin-1 and -2 secretion by colonic epithelial cells. © FASEB.

Serum 7 alpha-hydroxy-4-cholesten-3-one and selenohomocholyltaurine (SeHCAT) whole body retention in the assessment of bile acid induced diarrhoea.

PubMed

Brydon, W G; Nyhlin, H; Eastwood, M A; Merrick, M V

1996-02-01

To assess the reliability of serum 7 alpha-hydroxy-4-cholesten-3-one (7 alpha-3ox-C) in the differential diagnosis of bile acid induced diarrhoea by comparison with 75selenohomocholyltaurine whole body retention (SeHCAT WBR). One hundred and sixty-four patients with chronic diarrhoea were investigated prospectively in two centres (Edinburgh and Sweden) by two different tests which measure bile acid loss or synthesis: the SeHCAT test which measures the 7-day SeHCAT WBR and serum 7 alpha-3ox-C which reflects the rate of bile acid synthesis. Forty-six patients had SeHCAT WBR of less than 10% (19 with ileal disease or resection, nine with idiopathic bile acid induced diarrhoea and 18 with miscellaneous causes for bile acid induced diarrhoea). All patients with ileal or idiopathic disease showed a favorable response to treatment as did 13 of the miscellaneous group. Serum 7 alpha-3ox-C was raised in all subjects with ileal disease/resection, seven patients with idiopathic disease and all subjects in the miscellaneous group who responded to treatment. Sixteen out of 118 patients with SeHCAT WBR greater than or equal to 10% had raised serum 7 alpha-3ox-C. The positive predictive value of serum 7 alpha-3ox-C was 74%. The high negative predictive value (98%) of serum 7 alpha-3ox-C indicates the possible use of this test for excluding bile acid malabsorption in this population. All but two subjects who responded to treatment had raised serum 7 alpha-3ox-C concentrations. The possibility that the sensitivity of the test can be improved by repeat testing needs to be further investigated. There was a significant correlation between fractional catabolic rate (FCR) SeHCAT and serum 7 alpha-3ox-C (r = 0.63, P < 0.0001). Further data are required to validate the reference range in women over 70 years of age.

Cholesterol 7α-hydroxylase protects the liver from inflammation and fibrosis by maintaining cholesterol homeostasis[S

PubMed Central

Liu, Hailiang; Pathak, Preeti; Boehme, Shannon; Chiang, John Y. L.

2016-01-01

Cholesterol 7α-hydroxylase (CYP7A1) plays a critical role in control of bile acid and cholesterol homeostasis. Bile acids activate farnesoid X receptor (FXR) and Takeda G protein-coupled receptor 5 (TGR5) to regulate lipid, glucose, and energy metabolism. However, the role of bile acids in hepatic inflammation and fibrosis remains unclear. In this study, we showed that adenovirus-mediated overexpression of Cyp7a1 ameliorated lipopolysaccharide (LPS)-induced inflammatory cell infiltration and pro-inflammatory cytokine production in WT and TGR5-deficient (Tgr5−/−) mice, but not in FXR-deficient (Fxr−/−) mice, suggesting that bile acid signaling through FXR protects against hepatic inflammation. Nuclear factor κ light-chain enhancer of activated B cells (NF-κB)-luciferase reporter assay showed that FXR agonists significantly inhibited TNF-α-induced NF-κB activity. Furthermore, chromatin immunoprecipitation and mammalian two-hybrid assays showed that ligand-activated FXR interacted with NF-κB and blocked recruitment of steroid receptor coactivator-1 to cytokine promoter and resulted in inhibition of NF-κB activity. Methionine/choline-deficient (MCD) diet increased hepatic inflammation, free cholesterol, oxidative stress, apoptosis, and fibrosis in CYP7A1-deficient (Cyp7a1−/−) mice compared with WT mice. Remarkably, adenovirus-mediated overexpression of Cyp7a1 effectively reduced hepatic free cholesterol and oxidative stress and reversed hepatic inflammation and fibrosis in MCD diet-fed Cyp7a1−/− mice. Current studies suggest that increased Cyp7a1 expression and bile acid synthesis ameliorate hepatic inflammation through activation of FXR, whereas reduced bile acid synthesis aggravates MCD diet-induced hepatic inflammation and fibrosis. Maintaining bile acid and cholesterol homeostasis is important for protecting against liver injury and nonalcoholic fatty liver disease. PMID:27534992

The diagnostic value of gastroesophageal reflux disease (GERD) symptoms and detection of pepsin and bile acids in bronchoalveolar lavage fluid and exhaled breath condensate for identifying lung transplantation patients with GERD-induced aspiration.

PubMed

Reder, Nicholas P; Davis, Christopher S; Kovacs, Elizabeth J; Fisichella, P Marco

2014-06-01

Gastroesophageal reflux disease (GERD) is thought to lead to aspiration and bronchiolitis obliterans syndrome after lung transplantation. Unfortunately, the identification of patients with GERD who aspirate still lacks clear diagnostic indicators. The authors hypothesized that symptoms of GERD and detection of pepsin and bile acids in the bronchoalveolar lavage fluid (BAL) and exhaled breath condensate (EBC) are effective for identifying lung transplantation patients with GERD-induced aspiration. From November 2009 to November 2010, 85 lung transplantation patients undergoing surveillance bronchoscopy were prospectively enrolled. For these patients, self-reported symptoms of GERD were correlated with levels of pepsin and bile acids in BAL and EBC and with GERD status assessed by 24-h pH monitoring. The sensitivity and specificity of pepsin and bile acids in BAL and EBC also were compared with the presence of GERD in 24-h pH monitoring. The typical symptoms of GERD (heartburn and regurgitation) had modest sensitivity and specificity for detecting GERD and aspiration. The atypical symptoms of GERD (aspiration and bronchitis) showed better identification of aspiration as measured by detection of pepsin and bile acids in BAL. The sensitivity and specificity of pepsin in BAL compared with GERD by 24-h pH monitoring were respectively 60 and 45 %, whereas the sensitivity and specificity of bile acids in BAL were 67 and 80 %. These data indicate that the measurement of pepsin and bile acids in BAL can provide additional data for identifying lung transplantation patients at risk for GERD-induced aspiration compared with symptoms or 24-h pH monitoring alone. These results support a diagnostic role for detecting markers of aspiration in BAL, but this must be validated in larger studies.

Remodeling of the Vibrio cholerae membrane by incorporation of exogenous fatty acids from host and aquatic environments

PubMed Central

Giles, David K.; Hankins, Jessica V.; Guan, Ziqiang; Trent, M. Stephen

2011-01-01

Summary The Gram-negative bacteria Vibrio cholerae poses significant public health concerns by causing an acute intestinal infection afflicting millions of people each year. V. cholerae motility, as well as virulence factor expression and outer membrane protein production, have been shown to be affected by bile (Childers & Klose, 2007). The current study examines the effects of bile on V. cholerae phospholipids. Bile exposure caused significant alterations to the phospholipid profile of V. cholerae but not of other enteric pathogens. These changes consisted of a quantitative increase and migratory difference in cardiolipin, decreases in phosphatidylglycerol and phosphatidylethanolamine, and the dramatic appearance of an unknown phospholipid determined to be lyso-phosphatidylethanolamine. Major components of bile were not responsible for the observed changes, but long chain polyunsaturated fatty acids, which are minor components of bile, were shown to be incorporated into phospholipids of V. cholerae. Although the bile-induced phospholipid profile was independent of the V. cholerae virulence cascade, we identified another relevant environment in which V. cholerae assimilates unique fatty acids into its membrane phospholipids—marine sediment. Our results suggest that Vibrio species possess unique machinery conferring the ability to take up a wider range of exogenous fatty acids than other enteric bacteria. PMID:21255114

Incorporation of Exogenous Fatty Acids Protects Enterococcus faecalis from Membrane-Damaging Agents

PubMed Central

Saito, Holly E.; Harp, John R.

2014-01-01

Enterococcus faecalis is a commensal bacterium of the mammalian intestine that can persist in soil and aquatic systems and can be a nosocomial pathogen to humans. It employs multiple stress adaptation strategies in order to survive such a wide range of environments. Within this study, we sought to elucidate whether membrane fatty acid composition changes are an important component for stress adaptation. We noted that E. faecalis OG1RF was capable of changing its membrane composition depending upon growth phase and temperature. The organism also readily incorporated fatty acids from bile, serum, and medium supplemented with individual fatty acids, often dramatically changing the membrane composition such that a single fatty acid was predominant. Growth in either low levels of bile or specific individual fatty acids was found to protect the organism from membrane challenges such as high bile exposure. In particular, we observed that when grown in low levels of bile, serum, or the host-derived fatty acids oleic acid and linoleic acid, E. faecalis was better able to survive the antibiotic daptomycin. Interestingly, the degree of membrane saturation did not appear to be important for protection from the stressors examined here; instead, it appears that a specific fatty acid or combination of fatty acids is critical for stress resistance. PMID:25128342

A new method for identification of natural, artificial and in vitro cultured Calculus bovis using high-performance liquid chromatography-mass spectrometry

PubMed Central

Liu, Yonggang; Tan, Peng; Liu, Shanshan; Shi, Hang; Feng, Xin; Ma, Qun

2015-01-01

Objective: Calculus bovis have been widely used in Chinese herbology for the treatment of hyperpyrexia, convulsions, and epilepsy. Nowadays, due to the limited source and high market price, the substitutes, artificial and in vitro cultured Calculus bovis, are getting more and more commonly used. The adulteration phenomenon is serious. Therefore, it is crucial to establish a fast and simple method in discriminating the natural, artificial and in vitro cultured Calculus bovis. Bile acids, one of the main active constituents, are taken as an important indicator for evaluating the quality of Calculus bovis and the substitutes. Several techniques have been built to analyze bile acids in Calculus bovis. Whereas, as bile acids are with poor ultraviolet absorbance and high structural similarity, effective technology for identification and quality control is still lacking. Methods: In this study, high-performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (LC/MS/MS) was applied in the analysis of bile acids, which effectively identified natural, artificial and in vitro cultured Calculus bovis and provide a new method for their quality control. Results: Natural, artificial and in vitro cultured Calculus bovis were differentiated by bile acids analysis. A new compound with protonated molecule at m/z 405 was found, which we called 3α, 12α-dihydroxy-7-oxo-5α-cholanic acid. This compound was discovered in in vitro cultured Calculus bovis, but almost not detected in natural and artificial Calculus bovis. A total of 13 constituents was identified. Among them, three bio-markers, including glycocholic acid, glycodeoxycholic acid and taurocholic acid (TCA) were detected in both natural and artificial Calculus bovis, but the density of TCA was different in two kinds of Calculus bovis. In addition, the characteristics of bile acids were illustrated. Conclusions: The HPLC coupled with tandem MS (LC/MS/MS) method was feasible, easy, rapid and accurate in identifying natural, artificial and in vitro cultured Calculus bovis. PMID:25829769

Modulation of transport and metabolism of bile acids and bilirubin by chlorogenic acid against hepatotoxicity and cholestasis in bile duct ligation rats: involvement of SIRT1-mediated deacetylation of FXR and PGC-1α.

PubMed

Zhu, Lili; Wang, Lei; Cao, Fei; Liu, Peng; Bao, Haidong; Yan, Yumei; Dong, Xin; Wang, Dong; Wang, Zhongyu; Gong, Peng

2018-03-01

The purpose of the present study was to investigate the effect and potential mechanism of chlorogenic acid (CA) on liver injury induced by cholestasis in a rat model of bile duct ligation (BDL). Rats received vehicle or CA (20, 50, or 100 mg/kg per day) orally for 3 days. On the 4th day, the rats underwent sham or BDL surgery, and were orally administrated vehicle or CA for 3 or 7 days. mRNA and protein expression levels were evaluated by qRT-PCR and western blot. After BDL, plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), and total bile acids (TBA) were increased and typical pathological changes were observed in liver morphology. Hepatic uptake transporters (Ntcp, Oatp 1a4, and Oatp 1b2) were downregulated, while efflux transporters (Bsep and Mrp 2/3/4) were upregulated. BDL inhibited the expressions of Cyp7a1, Cyp8b1, and Cyp27a1 and induced Ugt1a1. CA treatment decreased ALT, AST, TBIL, and TBA (P < 0.05) and alleviated the liver pathological changes. The degree of expression changes in the transporters and enzymes was extended by CA (P < 0.05). SIRT1 protein was induced after CA treatment in BDL rats. Chlorogenic acid attenuated hepatotoxicity and cholestasis by decreasing the uptake and synthesis of bilirubin and bile acids and accelerating the metabolism and efflux of bilirubin and bile acids. © 2018 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

Heterogeneous accumulation of fluorescent bile acids in primary rat hepatocytes does not correlate with their homogenous expression of ntcp.

PubMed

Murray, John W; Thosani, Amar J; Wang, Pijun; Wolkoff, Allan W

2011-07-01

Sodium taurocholate-cotransporting polypeptide (ntcp) is considered to be a major determinant of bile acid uptake into hepatocytes. However, the regulation of ntcp and the degree that it participates in the accumulation of specific substrates are not well understood. We utilized fluorescent bile acid derivatives and direct quantitation of fluorescent microscopy images to examine the regulation of ntcp and its role in the cell-to-cell variability of fluorescent bile acid accumulation. Primary-cultured rat hepatocytes rapidly accumulated the fluorescent bile acids, chenodeoxycholylglycylamidofluorescein (CDCGamF), 7-β- nitrobenzoxadiazole 3-α hydroxy 5-β cholan-24-oic acid (NBD-CA), and cholyl-glycylamido-fluorescein (CGamF). However, in stably transfected HeLa cells, ntcp preferred CDCGamF, whereas the organic anion transporter, organic anion transporting polypeptide 1 (oatp1a1), preferred NBD-CA, and neither ntcp nor oatp1a1 showed strong accumulation of CGamF by these methods. Ntcp-mediated transport of CDCGamF was inhibited by taurocholate, cyclosporin, actin depolymerization, and an inhibitor of atypical PKC-ζ. The latter two agents altered the cellular distribution of ntcp as visualized in ntcp-green fluorescent protein-transfected cells. Although fluorescent bile acid accumulation was reproducible by the imaging assays, individual cells showed variable accumulation that was not attributable to changes in membrane permeability or cell viability. In HeLa cells, this was accounted for by variable levels of ntcp, whereas, in hepatocytes, ntcp expression was uniform, and low accumulation was seen in a large portion of cells despite the presence of ntcp. These studies indicate that single-cell imaging can provide insight into previously unrecognized details of anion transport in the complex environment of polarized hepatocytes.

Heterogeneous accumulation of fluorescent bile acids in primary rat hepatocytes does not correlate with their homogenous expression of ntcp

PubMed Central

Thosani, Amar J.; Wang, Pijun; Wolkoff, Allan W.

2011-01-01

Sodium taurocholate-cotransporting polypeptide (ntcp) is considered to be a major determinant of bile acid uptake into hepatocytes. However, the regulation of ntcp and the degree that it participates in the accumulation of specific substrates are not well understood. We utilized fluorescent bile acid derivatives and direct quantitation of fluorescent microscopy images to examine the regulation of ntcp and its role in the cell-to-cell variability of fluorescent bile acid accumulation. Primary-cultured rat hepatocytes rapidly accumulated the fluorescent bile acids, chenodeoxycholylglycylamidofluorescein (CDCGamF), 7-β- nitrobenzoxadiazole 3-α hydroxy 5-β cholan-24-oic acid (NBD-CA), and cholyl-glycylamido-fluorescein (CGamF). However, in stably transfected HeLa cells, ntcp preferred CDCGamF, whereas the organic anion transporter, organic anion transporting polypeptide 1 (oatp1a1), preferred NBD-CA, and neither ntcp nor oatp1a1 showed strong accumulation of CGamF by these methods. Ntcp-mediated transport of CDCGamF was inhibited by taurocholate, cyclosporin, actin depolymerization, and an inhibitor of atypical PKC-ζ. The latter two agents altered the cellular distribution of ntcp as visualized in ntcp-green fluorescent protein-transfected cells. Although fluorescent bile acid accumulation was reproducible by the imaging assays, individual cells showed variable accumulation that was not attributable to changes in membrane permeability or cell viability. In HeLa cells, this was accounted for by variable levels of ntcp, whereas, in hepatocytes, ntcp expression was uniform, and low accumulation was seen in a large portion of cells despite the presence of ntcp. These studies indicate that single-cell imaging can provide insight into previously unrecognized details of anion transport in the complex environment of polarized hepatocytes. PMID:21474652

The bile acid turnover rate assessed with the (75)SeHCAT test is stable in chronic diarrhoea but slightly decreased in healthy subjects after a long period of time.

PubMed

Bajor, Antal; Kilander, Anders; Sjövall, Henrik; Rudling, Mats; Ung, Kjell-Arne

2008-11-01

The stability of bile acid turnover rate was evaluated retrospectively using repeat SeHCAT tests in patients with chronic diarrhoea and prospectively for 16 years in healthy subjects. The SeHCAT values were stable in 39 patients with chronic diarrhoea, as shown by a comparison of the test results [data presented as median and (25th-75th percentile)]: 18% (8-23) in the first test versus 14% (9-21) in the second test [n = 39, P = 0.37, time interval 44 months (16-68), repeatability index >95%]. In contrast, they were reduced after 16 years in healthy subjects: 38% (30-49.5) in the first test versus 31% (21-49.5) in the second test (P < 0.03). In healthy subjects, the body mass index increased by 13% from 23.2 kg/m(2) (21-24.6) to 26.2 kg/m(2) (22.5-27.8) (P < 0.01) during the 16 years. There was a negative correlation between hepatic bile acid synthesis and the SeHCAT values (r = -0.615, P = 0.02, n = 14). In conclusion, the turnover rate of bile acids is stable over a long period of time in patients with chronic diarrhoea irrespective of bile acid malabsorption, suggesting that a repeat SeHCAT test is dispensable. There is a significant negative correlation between bile acid synthesis and SeHCAT test results in healthy subjects. The SeHCAT test values are slightly reduced in healthy subjects after 16 years.

Interaction of fluvastatin with the liver-specific Na+ -dependent taurocholate cotransporting polypeptide (NTCP).

PubMed

Greupink, Rick; Dillen, Lieve; Monshouwer, Mario; Huisman, Maarten T; Russel, Frans G M

2011-11-20

It has been reported that polymorphisms in the organic anion transporting polypeptide 1B1 (OATP1B1, SLCO1B1) result in decreased hepatic uptake of simvastatin carboxy acid, the active metabolite of simvastatin. This is not the case for fluvastatin and it has been hypothesized that for this drug other hepatic uptake pathways exist. Here, we studied whether Na(+)-dependent taurocholate co-transporting polypeptide (NTCP, SLC10A1) can be an alternative hepatic uptake route for fluvastatin. Chinese Hamster Ovary cells transfected with human NTCP (CHO-NTCP) were used to investigate the inhibitory effect of fluvastatin and other statins on [(3)H]-taurocholic acid uptake ([(3)H]-TCA). Statin uptake by CHO-NTCP and cryopreserved human hepatocytes was assessed via LC-MS/MS. Fluvastatin appeared to be a potent and competitive inhibitor of [(3)H]-TCA uptake (IC(50) of 40μM), pointing to an interaction at the level of the bile acid binding pocket of NTCP. The inhibitory action of other statins was also studied, which revealed that statin inhibitory potency increased with molecular descriptors of lipophilicity: calculated logP (r(2)=0.82, p=0.034), logD(7.4) (r(2)=0.77, p=0.0001). Studies in CHO-NTCP cells showed that fluvastatin was indeed an NTCP substrate (K(m) 250±30μM, V(max) 1340±50ng/mg total cell protein/min). However, subsequent studies revealed that at clinically relevant plasma concentrations, NTCP contributed minimally to overall accumulation in human hepatocytes. In conclusion, fluvastatin interacts with NTCP at the level of the bile acid binding pocket and is an NTCP substrate. However, under normal conditions, NTCP-mediated uptake of this drug seems not to be a significant hepatocellular uptake pathway. Copyright © 2011 Elsevier B.V. All rights reserved.

Enterohepatic circulation in man of a gamma-emitting bile-acid conjugate, 23-selena-25-homotaurocholic acid (SeHCAT).

PubMed

Merrick, M V; Eastwood, M A; Anderson, J R; Ross, H M

1982-02-01

A conjugated bile acid, 23-selena-25-homotaurocholic acid (SeHCAT), labeled with the gamma emitter Se-75, has been evaluated in man. Absorption and excretion were compared with that of simultaneously administered [23-14C]cholic acid. SeHCAT is absorbed quantitatively following oral administration, secreted into the bile at the same rate as cholic acid, reabsorbed from the small intestine, and resecreted. It is not absorbed when the terminal ileum has been excised or bypassed. SeHCAT is therefore the first of a new class of radiopharmaceuticals, namely, gamma-emitting tracers of the complete cycle of the enterohepatic circulation. Its use will simplify investigation of the functional state of the terminal ileum by eliminating the need to collect and process feces.

Functional microbiomics: Evaluation of gut microbiota-bile acid metabolism interactions in health and disease.

PubMed

Mullish, Benjamin H; Pechlivanis, Alexandros; Barker, Grace F; Thursz, Mark R; Marchesi, Julian R; McDonald, Julie A K

2018-04-26

There is an ever-increasing recognition that bile acids are not purely simple surfactant molecules that aid in lipid digestion, but are a family of molecules contributing to a diverse range of key systemic functions in the host. It is now also understood that the specific composition of the bile acid milieu within the host is related to the expression and activity of bacterially-derived enzymes within the gastrointestinal tract, as such creating a direct link between the physiology of the host and the gut microbiota. Coupled to the knowledge that perturbation of the structure and/or function of the gut microbiota may contribute to the pathogenesis of a range of diseases, there is a high level of interest in the potential for manipulation of the gut microbiota-host bile acid axis as a novel approach to therapeutics. Much of the growing understanding of the biology of this area reflects the recent development and refinement of a range of novel techniques; this study applies a number of those techniques to the analysis of human samples, aiming to illustrate their strengths, drawbacks and biological significance at all stages. Specifically, we used microbial profiling (using 16S rRNA gene sequencing), bile acid profiling (using liquid chromatography-mass spectrometry), bsh and baiCD qPCR, and a BSH enzyme activity assay to demonstrate differences in the gut microbiota and bile metabolism in stool samples from healthy and antibiotic-exposed individuals. Copyright © 2018 Elsevier Inc. All rights reserved.

Downregulation of peroxiredoxin-3 by hydrophobic bile acid induces mitochondrial dysfunction and cellular senescence in human trophoblasts

PubMed Central

Wu, Wei-Bin; Menon, Ramkumar; Xu, Yue-Ying; Zhao, Jiu-Ru; Wang, Yan-Lin; Liu, Yuan; Zhang, Hui-Juan

2016-01-01

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific disorder characterised by raised bile acids in foetal-maternal circulation, which threatens perinatal health. During the progression of ICP, the effect of oxidative stress is underscored. Peroxiredoxin-3 (PRDX3) is a mitochondrial antioxidant enzyme that is crucial to balance intracellular oxidative stress. However, the role of PRDX3 in placental trophoblast cells under ICP is not fully understood. We demonstrated that the level of PRDX3 was downregulated in ICP placentas as well as bile acids–treated trophoblast cells and villous explant in vitro. Toxic levels of bile acids and PRDX3 knockdown induced oxidative stress and mitochondrial dysfunction in trophoblast cells. Moreover, silencing of PRDX3 in trophoblast cell line HTR8/SVneo induced growth arrest and cellular senescence via activation of p38-mitogen-activated protein kinase (MAPK) and induction of p21WAF1/CIP and p16INK4A. Additionally, enhanced cellular senescence, determined by senescence-associated beta-galactosidase staining, was obviously attenuated by p38-MAPK inhibitor SB203580. Our data determined that exposure to bile acid decreased PRDX3 level in human trophoblasts. PRDX3 protected trophoblast cells against mitochondrial dysfunction and cellular senescence induced by oxidative stress. Our results suggest that decreased PRDX3 by excessive bile acids in trophoblasts plays a critical role in the pathogenesis and progression of ICP. PMID:27958341

Research on choleretic effect of menthol, menthone, pluegone, isomenthone, and limonene in DanShu capsule.

PubMed

Hu, Guanying; Yuan, Xing; Zhang, Sanyin; Wang, Ruru; Yang, Miao; Wu, Chunjie; Wu, Zhigang; Ke, Xiao

2015-02-01

Danshu capsule (DSC) is a medicinal compound in traditional Chinese medicine (TCM). It is commonly used for the treatment of acute & chronic cholecystitis as well as choleithiasis. To study its choleretic effect, healthy rats were randomly divided into DSC high (DSCH, 900mg/kg), medium (DSCM, 450mg/kg), and low (DSCL, 225mg/kg) group, Xiaoyan Lidan tablet (XYLDT, 750mg/kg), and saline group. The bile was collected for 1h after 20-minute stabilization as the base level, and at 1h, 2h, 3h, and 4h after drug administration, respectively. Bile volume, total cholesterol, and total bile acid were measured at each time point. The results revealed that DSC significantly stimulated bile secretion, decreased total cholesterol level and increased total bile acid level. Therefore, it had choleretic effects. To identify the active components contributing to its choleretic effects, five major constituents which are menthol (39.33mg/kg), menthone (18.02mg/kg), isomenthone (8.18mg/kg), pluegone (3.31mg/kg), and limonene (4.39mg/kg) were tested on our rat model. The results showed that menthol and limonene could promote bile secretion when compared to DSC treatment (p > 0.05); Menthol, menthol and limonene could significantly decrease total cholesterol level (p<0.05 or p<0.01) as well as increase total bile acid level (p<0.05 or p<0.01); Isomenthone, as a isomer of menthone, existed slightly choleretic effects; Pluegone had no obvious role in bile acid efflux. These findings indicated that the choleretic effects of DSC may be attributed mainly to its three major constituents: menthol, menthone and limonene. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

A novel mechanism of acid and bile acid-induced DNA damage involving Na+/H+ exchanger: implication for Barrett's oesophagus.

PubMed

Goldman, Aaron; Shahidullah, Mohammad; Goldman, David; Khailova, Ludmila; Watts, George; Delamere, Nicholas; Dvorak, Katerina

2010-12-01

Barrett's oesophagus is a premalignant disease associated with oesophageal adenocarcinoma. The major goal of this study was to determine the mechanism responsible for bile acid-induced alteration in intracellular pH (pH(i)) and its effect on DNA damage in cells derived from normal oesophagus (HET1A) or Barrett's oesophagus (CP-A). Cells were exposed to bile acid cocktail (BA) and/or acid in the presence/absence of inhibitors of nitric oxide synthase (NOS) or sodium-hydrogen exchanger (NHE). Nitric oxide (NO), pH(i) and DNA damage were measured by fluorescent imaging and comet assay. Expression of NHE1 and NOS in cultured cells and biopsies from Barrett's oesophagus or normal squamous epithelium was determined by RT-PCR, immunoblotting or immunohistochemistry. A dose dependent decrease in pH(i) was observed in CP-A cells exposed to BA. This effect of BA is the consequence of NOS activation and increased NO production, which leads to NHE inhibition. Exposure of oesophageal cells to acid in combination with BA synergistically decreased pH(i). The decrease was more pronounced in CP-A cells and resulted in >2-fold increase in DNA damage compared to acid treatment alone. Examination of biopsies and cell lines revealed robust expression of NHE1 in Barrett's oesophagus but an absence of NHE1 in normal epithelium. The results of this study identify a new mechanism of bile acid-induced DNA damage. We found that bile acids present in the refluxate activate immediately all three isoforms of NOS, which leads to an increased NO production and NHE inhibition. This consequently results in increased intracellular acidification and DNA damage, which may lead to mutations and cancer progression. Therefore, we propose that in addition to gastric reflux, bile reflux should be controlled in patients with Barrett's oesophagus.

Ursodeoxycholic Acid in Treatment of Non-cholestatic Liver Diseases: A Systematic Review.

PubMed

Reardon, Jillian; Hussaini, Trana; Alsahafi, Majid; Azalgara, Vladimir Marquez; Erb, Siegfried R; Partovi, Nilufar; Yoshida, Eric M

2016-09-28

Aims: To systematically evaluate the literature for evidence to support the use of bile acids in non-cholestatic liver conditions. Methods: Searches were conducted on the databases of Medline (1948-March 31, 2015), Embase (1980-March 31, 2015) and the Cochrane Central Register of Controlled Trials, and on Google and Google Scholar to identify articles describing ursodeoxycholic acid (UDCA) and its derivatives for non-cholestatic hepatic indications. Combinations of the following search terms were used: ursodeoxycholic acid, ursodiol, bile acids and/or salts, non alcoholic fatty liver, non alcoholic steatohepatitis, fatty liver, alcoholic hepatitis, alcohol, liver disease, autoimmune, autoimmune hepatitis, liver transplant, liver graft, transplant rejection, graft rejection, ischemic reperfusion injury, reperfusion injury, hepatitis B, hepatitis C, viral hepatitis, chronic hepatitis, acute hepatitis, transaminases, alanine transaminase, liver enzymes, aspartate aminotransferase, gamma-glutamyl transferase, gamma-glutamyl transpeptidase, bilirubin, alkaline phosphatase. No search limits were applied. Additionally, references of the included studies were reviewed to identify additional articles. Results: The literature search yielded articles meeting inclusion criteria for the following indications: non-alcoholic fatty liver disease (n = 5); alcoholic liver disease (n = 2); autoimmune hepatitis (n = 6), liver transplant (n = 2) and viral hepatitis (n = 9). Bile acid use was associated with improved normalization of liver biochemistry in non-alcoholic fatty liver disease, autoimmune hepatitis and hepatitis B and C infections. In contrast, liver biochemistry normalization was inconsistent in alcoholic liver disease and liver transplantation. The majority of studies reviewed showed that normalization of liver biochemistry did not correlate to improvement in histologic disease. In the prospective trials reviewed, adverse effects associated with the bile acids were limited to minor gastrointestinal complaints (most often, diarrhea) and did not occur at increased frequency as compared to controls. As administration of bile acids was often limited to durations of 12 months or less, long-term side effects for non-cholestatic indications cannot be excluded. Conclusions: Based on the available literature, bile acids cannot be widely recommended for non-cholestatic liver diseases at present.

New fluorescent bile acids: synthesis, chemical characterization, and disastereoselective uptake by Caco-2 cells of 3-deoxy 3-NBD-amino deoxycholic and ursodeoxycholic acid.

PubMed

Májer, Ferenc; Salomon, Johanna J; Sharma, Ruchika; Etzbach, Simona V; Najib, Mohd Nadzri Mohd; Keaveny, Ray; Long, Aideen; Wang, Jun; Ehrhardt, Carsten; Gilmer, John F

2012-03-01

Deoxycholic acid (DCA), a secondary bile acid (BA), and ursodeoxycholic acid (UDCA), a tertiary BA, cause opposing effects in vivo and in cell suspensions. Fluorescent analogues of DCA and UDCA could help investigate important questions about their cellular interactions and distribution. We have prepared a set of isomeric 3α- and 3β-amino analogues of UDCA and DCA and derivatised these with the discrete fluorophore, 4-nitrobenzo-2-oxa-1,3-diazol (NBD), forming the corresponding four fluorescent adducts. These absorb in the range 465-470 nm and fluoresce at approx. 535 nm. In order to determine the ability of the new fluorescent bile acids to mimic the parents, their uptake was studied using monolayers of Caco-2 cells, which are known to express multiple proteins of the organic anion-transporting peptide (OATP) subfamily of transporters. Cellular uptake was monitored over time at 4 and 37°C to distinguish between passive and active transport. All four BA analogues were taken up but in a strikingly stereo- and structure-specific manner, suggesting highly discriminatory interactions with transporter protein(s). The α-analogues of DCA and to a lesser extent UDCA were actively transported, whereas the β-analogues were not. The active transport process was saturable, with Michaelis-Menten constants for 3α-NBD DCA (5) being K(m)=42.27±12.98 μM and V(max)=2.8 ± 0.4 nmol/(mg protein*min) and for 3α-NBD UDCA (3) K(m)=28.20 ± 7.45 μM and V(max)=1.8 ± 0.2 nmol/(mg protein*min). These fluorescent bile acids are promising agents for investigating questions of bile acid biology and for detection of bile acids and related organic anion transport processes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Bile alcohol metabolism in man. Conversion of 5beta-cholestane-3alpha, 7alpha,12alpha, 25-tetrol to cholic acid.

PubMed Central

Salen, G; Shefer, S; Setoguchi, T; Mosbach, E H

1975-01-01

To study the role of C25-HYDROXY BILE ALCOHOLS AS PRECURSORS OF CHOlic acid, [G-3-H]5beta-cholestane-3alpha,7alpha12alpha,25-tetrol was administered intravenously to two subjects with cerebrotendinous xanthomatosis (CTX) and two normal individuals. One day after pulse labeling, radioactivity was present in the cholic acid isolated from the bile and feces of the subjects with CTX and the bile of the normal individuals. In the two normal subjects, the sp act decay curves of [G-3-H]-cholic acid were exponential, and no traces of [G-3-H]-5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol were detected. In contrast, appreciable quantities of labeled 5beta-cholestane-3alpha,-7aopha,12alpha,25-tetrol were present in the bile and feces of the CTX subjects. The sp act vs. time curves of fecal [G-3-H]5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol and [G-3-H]-cholic acid showed a precursor-product relationship. Although these results suggest that 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol may be a precursor of cholic acid in man, the possibility that C26-hydroxy intermediates represent the normal pathway can not be excluded. PMID:1141434

Idiopathic bile acid malabsorption--a review of clinical presentation, diagnosis, and response to treatment.

PubMed Central

Williams, A J; Merrick, M V; Eastwood, M A

1991-01-01

Between 1982 and 1989, the seven day retention of 75SeHCAT was measured in 181 patients with chronic diarrhoea that remained unexplained after full investigation. Altogether 121 of the 181 had a seven day 75SeHCAT retention greater than or equal to 15% and thus had no evidence of abnormal bile acid turnover. Twenty one had a seven day 75SeHCAT retention greater than or equal to 10% but less than 15%. Their clinical features were typical of the irritable bowel syndrome, and none of eight treated with cholestyramine showed symptomatic improvement. Sixteen patients had a seven day retention greater than or equal to 5% and less than 10%, six of whom had improved symptoms after treatment with bile acid chelating agents. The remaining 23 patients had a 75SeHCAT retention of less than 5% at seven days and responded to bile acid chelators. This group had a characteristic illness with intermittent watery diarrhoea, but no constitutional upset. It was not possible to distinguish the patients with bile acid malabsorption exclusively on the basis of the clinical symptoms and investigations, other than 75SeHCAT retention. We conclude that the measurement of 75SeHCAT retention is useful, appropriate, and necessary in patients with unexplained chronic diarrhoea. PMID:1916479

Hepatic alterations are accompanied by changes to bile acid transporter-expressing neurons in the hypothalamus after traumatic brain injury.

PubMed

Nizamutdinov, Damir; DeMorrow, Sharon; McMillin, Matthew; Kain, Jessica; Mukherjee, Sanjib; Zeitouni, Suzanne; Frampton, Gabriel; Bricker, Paul Clint S; Hurst, Jacob; Shapiro, Lee A

2017-01-20

Annually, there are over 2 million incidents of traumatic brain injury (TBI) and treatment options are non-existent. While many TBI studies have focused on the brain, peripheral contributions involving the digestive and immune systems are emerging as factors involved in the various symptomology associated with TBI. We hypothesized that TBI would alter hepatic function, including bile acid system machinery in the liver and brain. The results show activation of the hepatic acute phase response by 2 hours after TBI, hepatic inflammation by 6 hours after TBI and a decrease in hepatic transcription factors, Gli 1, Gli 2, Gli 3 at 2 and 24 hrs after TBI. Bile acid receptors and transporters were decreased as early as 2 hrs after TBI until at least 24 hrs after TBI. Quantification of bile acid transporter, ASBT-expressing neurons in the hypothalamus, revealed a significant decrease following TBI. These results are the first to show such changes following a TBI, and are compatible with previous studies of the bile acid system in stroke models. The data support the emerging idea of a systemic influence to neurological disorders and point to the need for future studies to better define specific mechanisms of action.

Hepatic alterations are accompanied by changes to bile acid transporter-expressing neurons in the hypothalamus after traumatic brain injury

PubMed Central

Nizamutdinov, Damir; DeMorrow, Sharon; McMillin, Matthew; Kain, Jessica; Mukherjee, Sanjib; Zeitouni, Suzanne; Frampton, Gabriel; Bricker, Paul Clint S.; Hurst, Jacob; Shapiro, Lee A.

2017-01-01

Annually, there are over 2 million incidents of traumatic brain injury (TBI) and treatment options are non-existent. While many TBI studies have focused on the brain, peripheral contributions involving the digestive and immune systems are emerging as factors involved in the various symptomology associated with TBI. We hypothesized that TBI would alter hepatic function, including bile acid system machinery in the liver and brain. The results show activation of the hepatic acute phase response by 2 hours after TBI, hepatic inflammation by 6 hours after TBI and a decrease in hepatic transcription factors, Gli 1, Gli 2, Gli 3 at 2 and 24 hrs after TBI. Bile acid receptors and transporters were decreased as early as 2 hrs after TBI until at least 24 hrs after TBI. Quantification of bile acid transporter, ASBT-expressing neurons in the hypothalamus, revealed a significant decrease following TBI. These results are the first to show such changes following a TBI, and are compatible with previous studies of the bile acid system in stroke models. The data support the emerging idea of a systemic influence to neurological disorders and point to the need for future studies to better define specific mechanisms of action. PMID:28106051

Effects of pelleted or powdered diets containing soy protein or sodium caseinate on lipid concentrations and bile acid excretion in golden Syrian hamsters.

PubMed

Butteiger, Dustie N; Krul, Elaine S

2015-08-01

Custom diets are a convenient vector for oral administration of test articles, but the processing and physical form of a diet can affect its nutritional properties and how it is consumed. Here, the authors evaluated the feeding behavior and physiology of golden Syrian hamsters fed diets of either soy or caseinate protein in pelleted or powdered forms for 28 d to determine whether dietary processing and form mediates the physiological effects of dietary proteins. The authors compared body weight, food consumption, serum cholesterol concentration, serum triglyceride concentration, fecal weight and fecal excretion of bile acids between treatment groups. Hamsters fed powdered diets showed higher food consumption than hamsters fed pelleted diets, regardless of protein source. Hamsters fed soy pelleted diets showed lower serum cholesterol concentration and higher fecal excretion of bile acid than hamsters fed caseinate pelleted diets, and serum cholesterol concentration correlated strongly with fecal excretion of bile acid. This correlation suggests that the physiological effects of soy protein on cholesterol and excretion of bile acid might be related or similarly mediated through diet. The differences observed between hamsters on different diets indicate that dietary form can influence both feeding behavior and the physiological effects of a diet in hamsters.

Tailoring acyclovir prodrugs with enhanced antiviral activity: rational design, synthesis, human plasma stability and in vitro evaluation.

PubMed

Chayrov, Radoslav L; Stylos, Evgenios K; Chatziathanasiadou, Maria V; Chuchkov, Kiril N; Tencheva, Aleksandra I; Kostagianni, Androniki D; Milkova, Tsenka S; Angelova, Assia L; Galabov, Angel S; Shishkov, Stoyan A; Todorov, Daniel G; Tzakos, Andreas G; Stankova, Ivanka G

2018-05-19

Bile acid prodrugs have served as a viable strategy for refining the pharmaceutical profile of parent drugs through utilizing bile acid transporters. A series of three ester prodrugs of the antiherpetic drug acyclovir (ACV) with the bile acids cholic, chenodeoxycholic and deoxycholic were synthesized and evaluated along with valacyclovir for their in vitro antiviral activity against herpes simplex viruses type 1 and type 2 (HSV-1, HSV-2). The in vitro antiviral activity of the three bile acid prodrugs was also evaluated against Epstein-Barr virus (EBV). Plasma stability assays, utilizing ultra-high performance liquid chromatography coupled with tandem mass spectrometry, in vitro cytotoxicity and inhibitory experiments were conducted in order to establish the biological profile of ACV prodrugs. The antiviral assays demonstrated that ACV-cholate had slightly better antiviral activity than ACV against HSV-1, while it presented an eight-fold higher activity with respect to ACV against HSV-2. ACV-chenodeoxycholate presented a six-fold higher antiviral activity against HSV-2 with respect to ACV. Concerning EBV, the highest antiviral effect was demonstrated by ACV-chenodeoxycholate. Human plasma stability assays revealed that ACV-deoxycholate was more stable than the other two prodrugs. These results suggest that decorating the core structure of ACV with bile acids could deliver prodrugs with amplified antiviral activity.

Greater bile acid excretion with soy bean than with cow milk in infants.

PubMed

Potter, J M; Nestel, P J

1976-05-01

The excretion of fecal sterols and bile acids was measured in five infants from the 1st week of life to 2 or 3 months of age as the composition of their diet was changed from cow milk to soy bean milk. Bile acid excretion, adjusted for body weight, was initially lower during the 1st than during the 3rd week, when it reached adult values. The average excretion of bile acids was 6.8 mg/kg per day with soy bean milk and 3.6 mg/kg per day with cow milk. Net sterol excretion (total sterol output minus cholesterol intake) was also twice as high with soy bean milk and probably reflected enhancement of cholesterol re-excretion as well as of synthesis since the cholesterol content of soy beans is nil. However, net sterol excretion remained higher with soy bean than with cow milk even when egg yolk cholesterol was added to the soy bean milk. It is concluded that the substitution of soy bean milk for cow milk, which lowered the plasma cholesterol in all infants (even in the presence of dietary cholesterol) leads to an increase in bile acids and probably also in cholesterol excretion in young infants.

Urinary metabolic insights into host-gut microbial interactions in healthy and IBD children

PubMed Central

Martin, Francois-Pierre; Su, Ming-Ming; Xie, Guo-Xiang; Guiraud, Seu Ping; Kussmann, Martin; Godin, Jean-Philippe; Jia, Wei; Nydegger, Andreas

2017-01-01

AIM To identify metabolic signatures in urine samples from healthy and inflammatory bowel disease (IBD) children. METHODS We applied liquid chromatography and gas chromatography coupled to targeted mass spectrometry (MS)-based metabolite profiling to identify and quantify bile acids and host-gut microbial metabolites in urine samples collected from 21 pediatric IBD patients monitored three times over one year (baseline, 6 and 12 mo), and 27 age- and gender-matched healthy children. RESULTS urinary metabolic profiles of IBD children differ significantly from healthy controls. Such metabolic differences encompass central energy metabolism, amino acids, bile acids and gut microbial metabolites. In particular, levels of pyroglutamic acid, glutamic acid, glycine and cysteine, were significantly higher in IBD children in the course of the study. This suggests that glutathione cannot be optimally synthesized and replenished. Whilst alterations of the enterohepatic circulation of bile acids in pediatric IBD patients is known, we show here that non-invasive urinary bile acid profiling can assess those altered hepatic and intestinal barrier dysfunctions. CONCLUSION The present study shows how non-invasive sampling of urine followed by targeted MS-based metabonomic analysis can elucidate and monitor the metabolic status of children with different GI health/disease status. PMID:28611517

Bile acids: regulation of apoptosis by ursodeoxycholic acid

PubMed Central

Amaral, Joana D.; Viana, Ricardo J. S.; Ramalho, Rita M.; Steer, Clifford J.; Rodrigues, Cecília M. P.

2009-01-01

Bile acids are a group of molecular species of acidic steroids with peculiar physical-chemical and biological characteristics. At high concentrations they become toxic to mammalian cells, and their presence is pertinent in the pathogenesis of several liver diseases and colon cancer. Bile acid cytoxicity has been related to membrane damage, but also to nondetergent effects, such as oxidative stress and apoptosis. Strikingly, hydrophilic ursodeoxycholic acid (UDCA), and its taurine-conjugated form (TUDCA), show profound cytoprotective properties. Indeed, these molecules have been described as potent inhibitors of classic pathways of apoptosis, although their precise mode of action remains to be clarified. UDCA, originally used for cholesterol gallstone dissolution, is currently considered the first choice therapy for several forms of cholestatic syndromes. However, the beneficial effects of both UDCA and TUDCA have been tested in other experimental pathological conditions with deregulated levels of apoptosis, including neurological disorders, such as Alzheimer's, Parkinson's, and Huntington's diseases. Here, we review the role of bile acids in modulating the apoptosis process, emphasizing the anti-apoptotic effects of UDCA and TUDCA, as well as their potential use as novel and alternate therapeutic agents for the treatment of apoptosis-related diseases. PMID:19417220

Bile acids: regulation of apoptosis by ursodeoxycholic acid.

PubMed

Amaral, Joana D; Viana, Ricardo J S; Ramalho, Rita M; Steer, Clifford J; Rodrigues, Cecília M P

2009-09-01

Bile acids are a group of molecular species of acidic steroids with peculiar physical-chemical and biological characteristics. At high concentrations they become toxic to mammalian cells, and their presence is pertinent in the pathogenesis of several liver diseases and colon cancer. Bile acid cytoxicity has been related to membrane damage, but also to nondetergent effects, such as oxidative stress and apoptosis. Strikingly, hydrophilic ursodeoxycholic acid (UDCA), and its taurine-conjugated form (TUDCA), show profound cytoprotective properties. Indeed, these molecules have been described as potent inhibitors of classic pathways of apoptosis, although their precise mode of action remains to be clarified. UDCA, originally used for cholesterol gallstone dissolution, is currently considered the first choice therapy for several forms of cholestatic syndromes. However, the beneficial effects of both UDCA and TUDCA have been tested in other experimental pathological conditions with deregulated levels of apoptosis, including neurological disorders, such as Alzheimer's, Parkinson's, and Huntington's diseases. Here, we review the role of bile acids in modulating the apoptosis process, emphasizing the anti-apoptotic effects of UDCA and TUDCA, as well as their potential use as novel and alternate therapeutic agents for the treatment of apoptosis-related diseases.

Liver ischemia and ischemia-reperfusion induces and trafficks the multi-specific metal transporter Atp7b to bile duct canaliculi: possible preferential transport of iron into bile.

PubMed

Goss, John A; Barshes, Neal R; Karpen, Saul J; Gao, Feng-Qin; Wyllie, Samuel

2008-04-01

Both Atp7b (Wilson disease gene) and Atp7a (Menkes disease gene) have been reported to be trafficked by copper. Atp7b is trafficked to the bile duct canaliculi and Atp7a to the plasma membrane. Whether or not liver ischemia or ischemia-reperfusion modulates Atp7b expression and trafficking has not been reported. In this study, we report for the first time that the multi-specific metal transporter Atp7b is significantly induced and trafficked by both liver ischemia alone and liver ischemia-reperfusion, as judged by immunohistochemistry and Western blot analyses. Although hepatocytes also stained for Atp7b, localized intense staining of Atp7b was found on bile duct canaliculi. Inductive coupled plasma-mass spectrometry analysis of bile copper, iron, zinc, and manganese found a corresponding significant increase in biliary iron. In our attempt to determine if the increased biliary iron transport observed may be a result of altered bile flow, lysosomal trafficking, or glutathione biliary transport, we measured bile flow, bile acid phosphatase activity, and glutathione content. No significant difference was found in bile flow, bile acid phosphatase activity, and glutathione, between control livers and livers subjected to ischemia-reperfusion. Thus, we conclude that liver ischemia and ischemia-reperfusion induction and trafficking Atp7b to the bile duct canaliculi may contribute to preferential iron transport into bile.

Effects of endogenous hydrogen peroxide and glutathione on the stability of arsenic metabolites in rat bile.

PubMed

Kobayashi, Yayoi; Hirano, Seishiro

2008-10-01

Trivalent arsenicals such as arsenite (iAs(III)), monomethylarsonous acid (MMA(III)) and dimethylarsinous acid (DMA(III)) are more toxic than analogous pentavalent compounds such as arsenate (iAs(V)), monomethylarsonic acid (MMA(V)) and dimethylarsinic acid (DMA(V)). It has been reported that arsenic-glutathione (As-GSH) complexes such as arsenic triglutathione (ATG) and methylarsenic diglutathione (MADG) are major metabolites in rat bile following intravenous administration of iAs(III). Recently, we have shown that both ATG and MADG are unstable and easily hydrolyzed to iAs(III) and MMA(III), respectively, and that MMA(III) is oxidized to MMA(V) in bile. In the present study we report the effects of H(2)O(2) and GSH on the stability of As-GSH complexes in rat bile. Male SD rats were injected intravenously with saline or iAs(III) at a dose of 0.2 or 2.0 mg As/kg body weight, and bile fluid was collected on ice for 30 min. To estimate the stability of As-GSH complexes in bile, ATG or MADG was added to untreated, heat-treated, catalase-treated, or dialyzed bile, and then incubated at 37 degrees C for 10 min. Concentrations of biliary H(2)O(2) and GSH in the higher dose group were 12.6- and 4.5-times higher than the control value, respectively. Exogenously added trivalent arsenicals were oxidized to pentavalent arsenicals in the bile depending on the biliary concentration of H(2)O(2). Both catalase and dialysis prevented oxidation of trivalent arsenicals to the corresponding pentavalent compounds. Exogenously added GSH stabilized As-GSH complexes in bile. These results suggest that H(2)O(2) converts trivalent arsenicals to less toxic pentavalent arsenicals, whereas GSH prevents hydrolysis of As-GSH complexes and the generation of unconjugated toxic trivalent arsenicals.

Intestinal barrier integrity and function in infants with cholestasis.

PubMed

Abu Faddan, Nagla H; Sherif, Tahra M K; Mohammed, Omnia A; Nasif, Khalid A; El Gezawy, Ebtesam M

2017-01-01

The safety of the human body is maintained by effective monitoring of the mucosal surface integrity and protection against potentially harmful compounds. This function of the gut called intestinal barrier function can be affected by cholestasis and the absence of bile in the intestinal lumen. We aimed to determine whether the gut barrier integrity is impaired in infants with cholestasis by evaluation of the intestinal fatty acid binding proteins (I-FABP) and ileal bile acid binding protein (I-BABP) as markers of intestinal epithelial cell damage and plasma D-lactate level as a marker of gut wall permeability. This case-control study included 53 infants with cholestasis and 29 controls. Serum levels of I-FABP, I-BABP, and D-lactate were measured in all subjects. Both groups of patients with neonatal hepatitis and biliary atresia showed significantly higher levels of I-FABP and I-BABP than the controls. There were no differences in the serum D-lactate level between the cases and controls. There was no difference between the two groups of patients (I and II) regarding any of the parameters studied. No significant correlations between serum levels of I-FABP, I-BABP, or D-lactate and total or direct bilirubin levels were found in the cholestatic infants. The intestinal epithelial barrier integrity is breached nearly in all parts of the intestine in infants with cholestasis. Further research is recommended to determine the impact of this finding on the management of these infants. The relationship between physical intestinal barrier damage and its functional failure remains subject for further research.

Novel Therapies for Familial Hypercholesterolemia.

PubMed

Parizo, Justin; Sarraju, Ashish; Knowles, Joshua W

2016-11-01

Both HeFH and HoFH require dietary and lifestyle modification. Pharmacotherapy of adult HeFH patients is largely driven by the American Heart Association (AHA) algorithm. A high-potency statin is started initially with a goal low-density lipoprotein cholesterol (LDL-C) reduction of >50 %. The LDL-C target is adjusted to <100 or <70 mg/dL in subjects with coronary artery disease (CAD) with ezetimibe being second line. If necessary, a third adjunctive therapy, such as a PSCK9 inhibitor (not yet approved in children) or bile acid-binding resin, can be added. Finally, LDL-C apheresis can be considered in patients with LDL-C >300 mg/dL (or >200 mg/dL with significant CAD, although now approved for LDL-C as low as 160 mg/dL with CAD). Due to the early, severe LDL-C elevation in HoFH patients, concerning natural history, rarity of the condition, and nuances of treatment, all HoFH patients should be treated at a pediatric or adult center with HoFH experience. LDL-C apheresis should be considered as early as 5 years of age. However, apheresis availability and tolerability is limited and pharmacotherapy is required. Generally, the AHA algorithm with reference to the European Atherosclerosis Society Consensus Panel recommendations is reasonable with all patients initiated on high-dose, high-potency statin, ezetimibe, and bile acid-binding resins. In most, additional LDL-C lowering is required with PCSK9 inhibitors and/or lomitapide or mipomersen. Liver transplantation can also be considered at experienced centers as a last resort.

Lecithin inhibits fatty acid and bile salt absorption from rat small intestine in vivo.

PubMed

Saunders, D R; Sillery, J

1976-12-01

During digestion of a fatty meal, long chain free fatty acids (FFA) and lecithin are among the lipids solubilized in intestinal contents as mixed micelles with bile salts. We hypothesized that if lecithin were not hydrolyzed, the mixed micelles would be abnormal, and absorption of FFA and bile salts would be depressed. To test this hypothesis, isolated segments of rat small intestine were infused in vivo with micellar solutions of 2 mMolar linoleic acid and 10 mMolar taurocholate to which was added 3 mMolar 1-palmitoyl, 2-oleoyl lecithin (a common lecithin in bile and food), or 1-palmitoyl lysolecithin (the hydrolytic product of lecithin). Absorption of FFA and bile salt was measured under steady state conditions using a single-pass technique. Lecithin depressed the rate of FFA absorption by 40% (p less than 0.025) in jejunal and ileal segments whereas lysolecithin was associated with normal rates of FFA absorption. Lecithin also reduced taurocholate absorption from the ileum by 30% (p less than 0.05). These data support the idea that lecithin may depress FFA and bile salt absorption from the small intestine in pancreatic insufficiency.

Potential Functional Byproducts from Guava Purée Processing.

PubMed

Lim, Si Yi; Tham, Paik Yean; Lim, Hilary Yi Ler; Heng, Wooi Shin; Chang, Ying Ping

2018-05-10

The valorization of guava waste requires compositional and functional studies. We tested three byproducts of guava purée processing, namely refiner, siever, and decanter. We analyzed the chemical composition and quantified the prebiotic activity score and selected carbohydrates; we also determined the water holding (WHC), oil holding (OHC), cation exchange capacities, bile acid binding, and glucose dialysis retardation (GDR) of the solid fraction and the antioxidative and α-amylase inhibitory capacities (AIC) of the ethanolic extract. Refiner contained 7.7% lipid, 7.08% protein and a relatively high phytate content; it had a high prebiotic activity score and possessed the highest binding capacity with deoxycholic acid. Siever contained high levels of low molecular weight carbohydrates and total tannin but relatively low crude fiber and cellulose contents. It had the highest binding with chenodeoxycholic acid (74.8%), and exhibited the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity. Decanter was rich in cellulose and had a high prebiotic activity score. The WHC and OHC values of decanter were within a narrow range and also exhibited the highest binding with cholic acid (86.6%), and the highest values of GDR and AIC. The refiner waste could be included in animal feed but requires further processing to reduce the high phytate levels. All three guava byproducts had the potential to be a source of antioxidant dietary fiber (DF), a finding that warrants further in vivo study. To differing extents, the guava byproducts exhibited useful physicochemical binding properties and so possessed the potential for health-promoting activity. These byproducts could also be upgraded to other marketable products so the manufacturers of processed guava might be able to develop their businesses sustainably by making better use of them. © 2018 Institute of Food Technologists®.

Effect of various antibiotics on modulation of intestinal microbiota and bile acid profile in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Youcai; Limaye, Pallavi B.; Renaud, Helen J.

Antibiotic treatments have been used to modulate intestinal bacteria and investigate the role of intestinal bacteria on bile acid (BA) homeostasis. However, knowledge on which intestinal bacteria and bile acids are modified by antibiotics is limited. In the present study, mice were administered various antibiotics, 47 of the most abundant bacterial species in intestine, as well as individual BAs in plasma, liver, and intestine were quantified. Compared to the two antibiotic combinations (vancomycin + imipenem and cephalothin + neomycin), the three single antibiotics (metronidazole, ciprofloxacin and aztreonam) have less effect on intestinal bacterial profiles, and thus on host BA profilesmore » and mRNA expression of genes that are important for BA homeostasis. The two antibiotic combinations decreased the ratio of Firmicutes to Bacteroidetes in intestine, as well as most secondary BAs in serum, liver and intestine. Additionally, the two antibiotic combinations significantly increased mRNA of the hepatic BA uptake transporters (Ntcp and Oatp1b2) and canalicular BA efflux transporters (Bsep and Mrp2), but decreased mRNA of the hepatic BA synthetic enzyme Cyp8b1, suggesting an elevated enterohepatic circulation of BAs. Interestingly, the two antibiotic combinations tended to have opposite effect on the mRNAs of most intestinal genes, which tended to be inhibited by vancomycin + imipenem but stimulated by cephalothin + neomycin. To conclude, the present study clearly shows that various antibiotics have distinct effects on modulating intestinal bacteria and host BA metabolism. - Highlights: • Various antibiotics have different effects on intestinal bacteria. • Antibiotics alter bile acid composition in mouse liver and intestine. • Antibiotics influence genes involved in bile acid homeostasis. • Clostridia appear to be important for secondary bile acid formation.« less

Elevated fasting and postprandial C-terminal telopeptide after Roux-en-Y gastric bypass.

PubMed

Maghsoodi, Negar; Alaghband-Zadeh, Jamshid; Cross, Gemma F; Werling, Malin; Fändriks, Lars; Docherty, Neil G; Olbers, Torsten; Dew, Tracy; Sherwood, Roy A; Vincent, Royce P; le Roux, Carel W

2017-07-01

Background Roux-en-Y gastric bypass increases circulating bile acid concentrations, known mediators of postprandial suppression of markers of bone resorption. Long-term data, however, indicate that Roux-en-Y gastric bypass confers an increased risk of bone loss on recipients. Methods Thirty-six obese individuals, median age 44 (26-64) with median body mass index at baseline of 42.5 (40.4-46) were studied before and 15 months after Roux-en-Y gastric bypass. After an overnight fast, patients received a 400 kcal mixed meal. Blood samples were collected premeal then at 30-min periods for 120 min. Pre and postmeal samples were analysed for total bile acids, parathyroid hormone and C-terminal telopeptide. Results Body weight loss post Roux-en-Y gastric bypass was associated with a median 4.9-fold increase in peak postprandial total bile acid concentration, and a median 2.4-fold increase in cumulative food evoked bile acid response. Median fasting parathyroid hormone, postprandial reduction in parathyroid hormone and total parathyroid hormone release over 120 min remained unchanged after surgery. After surgery, median fasting C-terminal telopeptide increased 2.3-fold, peak postprandial concentrations increased 3.8-fold and total release was increased 1.9-fold. Conclusions Fasting and postprandial total bile acids and C-terminal telopeptide are increased above reference range after Roux-en-Y gastric bypass. These changes occur in spite of improved vitamin D status with supplementation. These results suggest that post-Roux-en-Y gastric bypass increases in total bile acids do not effectively oppose an ongoing resorptive signal operative along the gut-bone axis. Serial measurement of C-terminal telopeptide may be of value as a risk marker for long-term skeletal pathology in patients post Roux-en-Y gastric bypass.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galatola, G.; Jazrawi, R.P.; Bridges, C.

The purpose of this study was to develop and validate a method of directly measuring ileal bile acid absorption efficiency during a single enterohepatic cycle (first-pass ileal clearance). This has become feasible for the first time because of the availability of the synthetic gamma-labeled bile acid 75Selena-homocholic acid-taurine (75SeHCAT). Together with the corresponding natural bile acid cholic acid-taurine (labeled with 14C), SeHCAT was infused distal to an occluding balloon situated beyond the ampulla of Vater in six healthy subjects. Completion of a single enterohepatic cycle was assessed by obtaining a plateau for 75SeHCAT activity proximal to the occluding balloon, whichmore » prevented further cycles. Unabsorbed 75SeHCAT was collected after total gut washout, which was administered distal to the occluding balloon. 75SeHCAT activity in the rectal effluent measured by gamma counter was compared with that of absorbed 75SeHCAT level measured by gamma camera and was used to calculate first-pass ileal clearance. This was very efficient (mean value, 96%) and showed very little variation in the six subjects studied (range, 95%-97%). A parallel time-activity course in hepatic bile for 14C and 75Se during a single enterohepatic cycle, together with a ratio of unity for 14C/75Se in samples obtained at different time intervals, suggests that 75SeHCAT is handled by the ileum like the natural bile acid cholic acid-taurine. Extrapolation of 75SeHCAT first-pass ileal clearance to that of the natural bile acid therefore seems justifiable. In a subsidiary experiment, ileal absorption efficiency per day for 75SeHCAT was also measured by scanning the gallbladder area on 5 successive days after the measurement of first-pass ileal clearance. In contrast with absorption efficiency per cycle, absorption efficiency per day varied widely (49%-86%).« less

Bile acids override steatosis in farnesoid X receptor deficient mice in a model of non-alcoholic steatohepatitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Weibin; Liu, Xijun; Peng, Xiaomin

Highlights: • FXR deficiency enhanced MCD diet-induced hepatic fibrosis. • FXR deficiency attenuated MCD diet-induced hepatic steatosis. • FXR deficiency repressed genes involved in fatty acid uptake and triglyceride accumulation. - Abstract: Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, and the pathogenesis is still not well known. The farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily and plays an essential role in maintaining bile acid and lipid homeostasis. In this study, we study the role of FXR in the pathogenesis of NFALD. We found that FXR deficient (FXR{sup −/−})more » mice fed methionine- and choline-deficient (MCD) diet had higher serum ALT and AST activities and lower hepatic triglyceride levels than wild-type (WT) mice fed MCD diet. Expression of genes involved in inflammation (VCAM-1) and fibrosis (α-SMA) was increased in FXR{sup −/−} mice fed MCD diet (FXR{sup −/−}/MCD) compared to WT mice fed MCD diet (WT/MCD). Although MCD diet significantly induced hepatic fibrosis in terms of liver histology, FXR{sup −/−}/MCD mice showed less degree of hepatic steatosis than WT/MCD mice. Moreover, FXR deficiency synergistically potentiated the elevation effects of MCD diet on serum and hepatic bile acids levels. The super-physiological concentrations of hepatic bile acids in FXR{sup −/−}/MCD mice inhibited the expression of genes involved in fatty acid uptake and triglyceride accumulation, which may be an explanation for less steatosis in FXR{sup −/−}/MCD mice in contrast to WT/MCD mice. These results suggest that hepatic bile acids accumulation could override simple steatosis in hepatic injury during the progression of NAFLD and further emphasize the role of FXR in maintaining hepatic bile acid homeostasis in liver disorders and in hepatic protection.« less

Transmembrane topology of the arsenite permease Acr3 from Saccharomyces cerevisiae.

PubMed

Wawrzycka, Donata; Markowska, Katarzyna; Maciaszczyk-Dziubinska, Ewa; Migocka, Magdalena; Wysocki, Robert

2017-01-01

Acr3 is a plasma membrane transporter, a member of the bile/arsenite/riboflavin transporter (BART) superfamily, which confers high-level resistance to arsenicals in the yeast Saccharomyces cerevisiae. We have previously shown that the yeast Acr3 acts as a low affinity As(III)/H + and Sb(III)/H + antiporter. We have also identified several amino acid residues that are localized in putative transmembrane helices (TM) and appeared to be critical for the Acr3 activity. In the present study, the topology of Acr3 was investigated by insertion of glycosylation and factor Xa protease cleavage sites at predicted hydrophilic regions. The analysis of the glycosylation pattern and factor Xa cleavage products of resulting Acr3 fusion constructs provide evidence supporting a topological model of Acr3 with 10 TM segments and cytoplasmically oriented N- and C-terminal domains. Next, we investigated the role of the hydrophilic loop connecting TM8 and TM9, the large size of which is unique to members of the yeast Acr3 family of metalloid transporters. We found that a 28 amino acid deletion in this region does not affect Acr3 folding, trafficking substrate binding, or transport activity. Finally, we constructed a homology-based structural model of Acr3 using the crystal structure of the Yersinia frederiksenii homologue of the human bile acid sodium symporter ASBT. Copyright © 2016 Elsevier B.V. All rights reserved.

Water-soluble quercetin modulates the choleresis and bile lipid ratio in rats.

PubMed

Vovkun, Tatiana; Yanchuk, Petro; Shtanova, Lidiya; Veselskiy, Stanislav; Filimonova, Natalia; Shalamay, Anatoly; Vedmid, Volodymyr

2018-01-01

Water-soluble analogue of quercetin, corvitin is used in patients with myocardial infarction as blocker of 5-lipoxygenase. However, its effects on secretion, lipid content and physico-chemical properties of bile have not been understood yet. We investigated the effect of corvitin, applied in different doses, on the level of bile flow, the content of bile free and esterified cholesterol, phospholipids, triacylglycerols, and free fatty acids. In order to determine stability of the bile colloidal system, we examined the relationship between different lipid components. The rats were injected intraportally with a bolus of corvitin. At doses of 2.5, 5, and 10 mg/kg, the latter increased bile flow and concentration of total cholates, as well as free fatty acids. Corvitin (5 mg/kg) elevated phospholipids and cholesterol content, but at a dose of 10 mg/kg it increased the concentration of bile cholesterol esters and triacylglycerols. Corvitin applied at doses of 2.5 and 10 mg/kg increased total cholates/cholesterol ratio, but at a dose of 10 mg/kg, the drug reduced cholesterol / esterified cholesterol ratio. The results suggest that corvitin exerts choleretic effect and improves stability of bile colloidal system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyd, G.S.; Merrick, M.V.; Monks, R.

Four selenium-labeled free bile acids and four selenium-labeled conjugated bile acids, labeled with Se-75 at the C-19, C-22, C-23, or C-24 position, have been synthesized and their absorption and excretion compared with that of (24-14C)cholic acid, following both oral and intravenous administration. All but one of the compounds is absorbed and excreted in bile to a significant extent. One compound, SeHCAT, has been selected for particular study. It is quantitatively absorbed from the gut at the same rate as cholic acid, and both are excreted into the bile at the same rate. It remains almost entirely confined to the enterohepaticmore » circulation (the gut, liver, and biliary tree) and excretion is exclusively fecal. Whole-body retention, measured for 41 days, and tissue distributions suggest that the absorbed radiation dose would be small compared with that in many established tests. Such a compound offers the possibility of a simple, novel, and aesthetically acceptable method of investigating small-bowel disease. It therefore merits further investigation.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amaral, H.; Palma, R.; Pfau, J.

Bile acid malabsorption has been recognized as an important cause of chronic diarrhea. Se-75HCAT, a bile acid, is absorbed in the terminal ileum. Therefore, measurement of its body retention indicate ileal function not requiring fecal collections. The authors studied 8 normal volunteers presenting with chronic recurrent diarrhea for more than 2 years. Each received orally a 10 ..mu..Ci capsule of SeHCAT (Amersham Intl.) and 3 hours later anterior and posterior whole body activity was measured using a digital camera without collimator. Measurements were repeated daily for 7 days and expressed as % of retention. Three patients had normal retention (1more » celiac disease, 1 inactive Crohn disease and 1 functional diarrhea), another was borderline (an immunodeficiency) and 4 patients presented abnormal bile acid absorption (2 had vagotomy, 1 Crohn disease and 1 idiopathic diarrhea). This last group was treated with cholestyramine showing improvement of the diarrhea, and relapse on drug withdrawal. These findings demonstrate that this technique can identify bile acid malabsorption as the cause of chronic diarrhea by external counting.« less

Measurement of serum 7α-hydroxy-4-cholesten-3-one as a marker of bile acid malabsorption in dogs with chronic diarrhoea: a pilot study

PubMed Central

Cross, G.; Taylor, D. R.; Sherwood, R. A.; Watson, P. J.

2016-01-01

Bile acid malabsorption is a common cause of chronic diarrhoea in people, however it has never previously been investigated in dogs, despite clinical suspicion of its existence. The goal of this study was to assess the feasibility of measuring serum 7α-hydroxy-4-cholesten-3-one (C4) in dogs, as a potential marker of bile acid malabsorption, and to see whether this is related to clinical disease severity or the presence of hypocobalaminaemia. Serum C4 concentration was measured in 20 clinically healthy control dogs and 17 dogs with chronic diarrhoea. Three of the 17 affected dogs (17.6 per cent) had a C4 concentration significantly above the range of clinically healthy dogs; these dogs were all poorly responsive to conventional therapy. These results suggest that bile acid malabsorption may be a clinically relevant disorder in dogs with chronic diarrhoea and serum C4 may be a useful tool to investigate this further. PMID:27110372

Measurement of serum 7α-hydroxy-4-cholesten-3-one as a marker of bile acid malabsorption in dogs with chronic diarrhoea: a pilot study.

PubMed

Kent, A C C; Cross, G; Taylor, D R; Sherwood, R A; Watson, P J

2016-01-01

Bile acid malabsorption is a common cause of chronic diarrhoea in people, however it has never previously been investigated in dogs, despite clinical suspicion of its existence. The goal of this study was to assess the feasibility of measuring serum 7α-hydroxy-4-cholesten-3-one (C4) in dogs, as a potential marker of bile acid malabsorption, and to see whether this is related to clinical disease severity or the presence of hypocobalaminaemia. Serum C4 concentration was measured in 20 clinically healthy control dogs and 17 dogs with chronic diarrhoea. Three of the 17 affected dogs (17.6 per cent) had a C4 concentration significantly above the range of clinically healthy dogs; these dogs were all poorly responsive to conventional therapy. These results suggest that bile acid malabsorption may be a clinically relevant disorder in dogs with chronic diarrhoea and serum C4 may be a useful tool to investigate this further.

Comparative metabolism and elimination of acetanilide compounds by rat.

PubMed

Davison, K L; Larsen, G L; Feil, V J

1994-10-01

1. 14C-labelled propachlor, alachlor, butachlor, metolachlor, methoxypropachlor and some of their mercapturic acid pathway metabolites (MAP) were given to rat either by gavage or by perfusion into a renal artery. MAP metabolites were isolated from bile and urine. 2. Rat gavaged with propachlor and methoxypropachlor eliminated 14C mostly in urine, whereas rat gavaged with alachlor, butachlor and metolachlor eliminated 14C about equally divided between urine and faeces. When bile ducts were cannulated, the gavaged rat eliminated most of the 14C in bile for all compounds. The amount of 14C in bile from the propachlor-gavaged rat was less than that for the other acetanilides, with the difference being in the urine. 3. The mercapturic acid metabolites 2-methylsulphinyl-N-(1-methylhydroxyethyl)-N-phenylacetam ide and 2-methylsulphinyl-N-(1-methylmethoxyethyl)-N-phenylacetam ide were isolated from the urine and bile of the methoxypropachlor-gavaged rat. 4. Bile was the major route for 14C elimination when MAP metabolites of alachlor, butachlor and metolachlor were perfused into a renal artery. Urine was the major route for 14C elimination when MAP metabolites of propachlor and methoxypropachlor were perfused. Mercapturic acid conjugates were major metabolites in bile and urine when MAP metabolites were perfused. 5. We conclude that alkyl groups on the phenyl portion of the acetanilide causes biliary elimination to be favoured over urinary elimination.

Sustained repression and translocation of Ntcp and expression of Mrp4 for cholestasis after rat 90% partial hepatectomy.

PubMed

Miura, Takuya; Kimura, Norihisa; Yamada, Toshiyuki; Shimizu, Takeshi; Nanashima, Naoki; Yamana, Daisuke; Hakamada, Kenichi; Tsuchida, Shigeki

2011-08-01

To clarify the mechanism of persistent cholestasis after massive hepatectomy, the relationship between such cholestasis and the expression and localization of organic anion transporters for bile acids was examined in a rat model. Male Sprague-Dawley rats were subjected to 90% hepatectomy, and tissues were harvested at 0, 1, 3, and 7 days for microarray analysis, quantitative real-time polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemistry to examine the expression of multidrug resistance protein 4 (Mrp4), bile salt export pump (Bsep), and sodium-dependent taurocholate cotransporting polypeptide (Ntcp). Persistently elevated levels of serum bile acids were observed at days 3 and 7. RT-PCR and Western blotting indicated that the expression of Mrp4, a bile acid export pump located in the basolateral membrane, was increased at day 3. The expression of Ntcp, a transporter used to uptake bile acids from the sinusoids, was significantly decreased throughout the period. The levels of Bsep, an export pump localized to the canalicular membrane, were unchanged. Immunohistochemistry revealed the localization of Mrp4 and Bsep in the basolateral and canalicular membranes, respectively. On the other hand, at days 3 and 7, Ntcp was localized in the cytoplasm and was hardly detected in the basolateral membrane. These results suggested that the sustained repression and translocation of Ntcp and the expression of Mrp4 at the basolateral membrane seem to be responsible for the high blood bile acids levels after massive hepatectomy. Copyright © 2010 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Comparative potency of obeticholic acid and natural bile acids on FXR in hepatic and intestinal in vitro cell models.

PubMed

Zhang, Yuanyuan; LaCerte, Carl; Kansra, Sanjay; Jackson, Jonathan P; Brouwer, Kenneth R; Edwards, Jeffrey E

2017-12-01

Obeticholic acid (OCA) is a semisynthetic farnesoid X receptor (FXR) agonist, an analogue of chenodeoxycholic acid (CDCA) which is indicated for the treatment of primary biliary cholangitis (PBC) in combination with ursodeoxycholic acid (UDCA). OCA efficiently inhibits bile acid synthesis and promotes bile acid efflux via activating FXR-mediated mechanisms in a physiologically relevant in vitro cell system, Sandwich-cultured Transporter Certified ™ human primary hepatocytes (SCHH). The study herein evaluated the effects of UDCA alone or in combination with OCA in SCHH. UDCA (≤100 μmol/L) alone did not inhibit CYP7A1 mRNA, and thus, no reduction in the endogenous bile acid pool observed. UDCA ≤100 μmol/L concomitantly administered with 0.1 μmol/L OCA had no effect on bile acid synthesis beyond what was observed with OCA alone. Furthermore, this study evaluated human Caco-2 cells (clone C2BBe1) as in vitro intestinal models. Glycine conjugate of OCA increased mRNA levels of FXR target genes in Caco-2 cells, FGF-19, SHP, OSTα/β, and IBABP, but not ASBT, in a concentration-dependent manner, while glycine conjugate of UDCA had no effect on the expression of these genes. The results suggested that UDCA ≤100 μmol/L did not activate FXR in human primary hepatocytes or intestinal cell line Caco-2. Thus, co-administration of UDCA with OCA did not affect OCA-dependent pharmacological effects. © 2017 The Authors. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics.

Binding and relaxation behavior of Coumarin-153 in lecithin-taurocholate mixed micelles: A time resolved fluorescence spectroscopic study

NASA Astrophysics Data System (ADS)

Chakrabarty, Debdeep; Chakraborty, Anjan; Seth, Debabrata; Hazra, Partha; Sarkar, Nilmoni

2005-09-01

The microenvironment of the bile salt-lecithin mixed aggregates has been investigated using steady state and picosecond time resolved fluorescence spectroscopy. The steady state spectra show that the polarity of the bile salt is higher compared to lecithin vesicles or the mixed aggregates. We have observed slow solvent relaxation in bile salt micelles and lecithin vesicles. The solvation time is gradually slowed down due to gradual addition of the bile salt in lecithin vesicles. Addition of bile salt leads to the tighter head group packing in lecithin. Thus, mobility of the water molecules becomes slower and consequently the solvation time is also retarded. We have observed bimodal slow rotational relaxation time in all these systems.

Pluronic®-bile salt mixed micelles.

PubMed

Patel, Vijay; Ray, Debes; Bahadur, Anita; Ma, Junhe; Aswal, V K; Bahadur, Pratap

2018-06-01

The present study was aimed to examine the interaction of two bile salts viz. sodium cholate (NaC) and sodium deoxycholate (NaDC) with three ethylene polyoxide-polypropylene polyoxide (PEO-PPO-PEO) triblock copolymers with similar PPO but varying PEO micelles with a focus on the effect of pH on mixed micelles. Mixed micelles of moderately hydrophobic Pluronic ® P123 were examined in the presence of two bile salts and compared with those from very hydrophobic L121 and very hydrophilic F127. Both the bile salts increase the cloud point (CP) of copolymer solution and decreased apparent micelle hydrodynamic diameter (D h ). SANS study revealed that P123 forms small spherical micelles showing a decrease in size on progressive addition of bile salts. The negatively charged mixed micelles contained fewer P123 molecules but progressively rich in bile salt. NaDC being more hydrophobic displays more pronounced effect than NaC. Interestingly, NaC shows micellar growth in acidic media which has been attributed to the formation of bile acids by protonation of carboxylate ion and subsequent solubilization. In contrast, NaDC showed phase separation at higher concentration. Nuclear Overhauser effect spectroscopy (NOESY) experiments provided information on interaction and location of bile salts in micelles. Results are discussed in terms of hydrophobicity of bile salts and Pluronics ® and the site of bile salt in polymer micelles. Proposed molecular interactions are useful to understand more about bile salts which play important role in physiological processes. Copyright © 2018 Elsevier B.V. All rights reserved.

Melatonin protects against taurolithocholic-induced oxidative stress in rat liver.

PubMed

Fuentes-Broto, Lorena; Miana-Mena, Francisco J; Piedrafita, Eduardo; Berzosa, César; Martínez-Ballarín, Enrique; García-Gil, Francisco A; Reiter, Russel J; García, Joaquín J

2010-08-01

Cholestasis, encountered in a variety of clinical disorders, is characterized by intracellular accumulation of toxic bile acids in the liver. Furthermore, oxidative stress plays an important role in the pathogenesis of bile acids. Taurolithocholic acid (TLC) was revealed in previous studies as the most pro-oxidative bile acid. Melatonin, a well-known antioxidant, is a safe and widely used therapeutic agent. Herein, we investigated the hepatoprotective role of melatonin on lipid and protein oxidation induced by TLC alone and in combination with FeCl(3) and ascorbic acid in rat liver homogenates and hepatic membranes. The lipid peroxidation products, malondialdehyde and 4-hydroxyalkenals (MDA + 4-HDA), and carbonyl levels were quantified as indices of oxidative damage to hepatic lipids and proteins, respectively. In the current study, the rise in MDA + 4-HDA levels induced by TLC was inhibited by melatonin in a concentration-dependent manner in both liver homogenates and in hepatic membranes. Melatonin also had protective effects against structural damage to proteins induced by TLC in membranes. These results suggest that the indoleamine melatonin may potentially act as a protective agent in the therapy of those diseases that involve bile acid toxicity. Published 2010 Wiley-Liss, Inc.

Lipidomics of human umbilical cord serum: identification of unique sterol sulfates.

PubMed

Wood, Paul L; Siljander, Heli; Knip, Mikael

2017-08-01

There are currently limited lipidomics data for human umbilical cord blood. Therefore, the lipidomes of cord sera from six newborns and sera from six nonpregnant females were compared. Sera lipidomics analyses were conducted using a high-resolution mass spectrometry analytical platform. Cord serum contained a diverse array of glycerophospholipids, albeit generally at lower concentrations than monitored in adult serum. The unexpected observations were that cord serum contained several neurosteroid sulfates and bile acid sulfates that were not detectable in adult serum. Our data are the first to demonstrate that cord serum contains bile acid sulfates that are synthesized early in the hydroxylase, neutral and acidic pathways of primary bile acid biosynthesis and support previous publications of cord blood perfluoralkyl toxins in newborns.

Mechanisms Underlying the Anti-Aging and Anti-Tumor Effects of Lithocholic Bile Acid

PubMed Central

Arlia-Ciommo, Anthony; Piano, Amanda; Svistkova, Veronika; Mohtashami, Sadaf; Titorenko, Vladimir I.

2014-01-01

Bile acids are cholesterol-derived bioactive lipids that play essential roles in the maintenance of a heathy lifespan. These amphipathic molecules with detergent-like properties display numerous beneficial effects on various longevity- and healthspan-promoting processes in evolutionarily distant organisms. Recent studies revealed that lithocholic bile acid not only causes a considerable lifespan extension in yeast, but also exhibits a substantial cytotoxic effect in cultured cancer cells derived from different tissues and organisms. The molecular and cellular mechanisms underlying the robust anti-aging and anti-tumor effects of lithocholic acid have emerged. This review summarizes the current knowledge of these mechanisms, outlines the most important unanswered questions and suggests directions for future research. PMID:25238416

The pathogenesis of post-irradiation chronic diarrhoea: measurement of SeHCAT and B12 absorption for differential diagnosis determines treatment.

PubMed

Ludgate, S M; Merrick, M V

1985-05-01

The absorption of vitamin B12 and of a synthetic bile acid analogue 75SeHCAT was measured simultaneously in 26 patients presenting with persistent diarrhoea following pelvic irradiation for treatment of carcinoma of the cervix. Four groups were identified, namely patients with isolated bile acid malabsorption, patients with isolated B12 malabsorption, patients with malabsorption of both and those with malabsorption of neither compound. The therapeutic implications are different for each. Measurement of B12 and bile acid absorption comprises an important new test for the management of patients with this disabling and unpleasant complication of radiotherapy.

Bile Formation and Secretion

PubMed Central

Boyer, James L.

2014-01-01

Bile is a unique and vital aqueous secretion of the liver that is formed by the hepatocyte and modified down stream by absorptive and secretory properties of the bile duct epithelium. Approximately 5% of bile consists of organic and inorganic solutes of considerable complexity. The bile-secretory unit consists of a canalicular network which is formed by the apical membrane of adjacent hepatocytes and sealed by tight junctions. The bile canaliculi (~1 μm in diameter) conduct the flow of bile countercurrent to the direction of portal blood flow and connect with the canal of Hering and bile ducts which progressively increase in diameter and complexity prior to the entry of bile into the gallbladder, common bile duct, and intestine. Canalicular bile secretion is determined by both bile salt-dependent and independent transport systems which are localized at the apical membrane of the hepatocyte and largely consist of a series of adenosine triphosphate-binding cassette transport proteins that function as export pumps for bile salts and other organic solutes. These transporters create osmotic gradients within the bile canalicular lumen that provide the driving force for movement of fluid into the lumen via aquaporins. Species vary with respect to the relative amounts of bile salt-dependent and independent canalicular flow and cholangiocyte secretion which is highly regulated by hormones, second messengers, and signal transduction pathways. Most determinants of bile secretion are now characterized at the molecular level in animal models and in man. Genetic mutations serve to illuminate many of their functions. PMID:23897680

Relation between bile acid reflux into the stomach and the risk of atrophic gastritis and intestinal metaplasia: a multicenter study of 2283 cases.

PubMed

Matsuhisa, Takeshi; Arakawa, Tetsuo; Watanabe, Tetsuo; Tokutomi, Tadashi; Sakurai, Kouichi; Okamura, Seisuke; Chono, Shinji; Kamada, Tomoari; Sugiyama, Atsushi; Fujimura, Yoshinori; Matsuzawa, Kenji; Ito, Masanori; Yasuda, Mitsugu; Ota, Hiroyoshi; Haruma, Ken

2013-09-01

The relationship between bile acid reflux into the stomach and the risk of atrophic gastritis and intestinal metaplasia is still not well understood. Towards obtaining a better understanding, concentrations of bile acids were measured. This study was carried out with the participation of 14 facilities in Japan, and 2283 samples were collected. The subjects with bile acid concentrations equal to or higher than the limit of detection were divided into four groups of equal size (group A: 0-25%, group B: 26-50%, group C: 51-75%, and group D: 76-100%). Thus, including the control group, there were five groups in total. The odds that the control group would develop atrophic gastritis and intestinal metaplasia was set as 1,and the odds ratios (OR) in groups A, B, C and D were calculated based on the odds in the control group. Regarding the development of atrophic gastritis, no increased risk was observed in either the Helicobacter pylori (H. pylori)-positive or -negative cases. The OR for the development of intestinal metaplasia were significantly higher, for both cases with and without H. pylori infection, in group D. High concentrations of bile acid seem to be associated with an elevated risk of intestinal metaplasia. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

From Reflux Esophagitis to Esophageal Adenocarcinoma

PubMed Central

Souza, Rhonda F.

2016-01-01

Reflux esophagitis causes Barrett's metaplasia, an abnormal esophageal mucosa predisposed to adenocarcinoma. Medical therapy for reflux esophagitis focuses on decreasing gastric acid production with proton pump inhibitors. We have reported that reflux esophagitis in a rat model develops from a cytokine-mediated inflammatory injury, not from a caustic chemical (acid) injury. In this model, refluxed acid and bile stimulate the release of inflammatory cytokines from esophageal squamous cells, recruiting lymphocytes first to the submucosa and later to the luminal surface. Emerging studies on acute reflux esophagitis in humans support this new concept, suggesting that reflux-induced cytokine release may be a future target for medical therapies. Sometimes, reflux esophagitis heals with Barrett's metaplasia, a process facilitated by reflux-related nitric oxide (NO) production and Sonic Hedgehog secretion by squamous cells. We have shown that NO reduces expression of genes that promote a squamous cell phenotype, while Hedgehog signaling induces genes that mediate the development of the columnar cell phenotypes of Barrett's metaplasia. Agents targeting esophageal NO production or Hedgehog signaling conceivably could prevent the development of Barrett's esophagus. Persistent reflux promotes cancer in Barrett's metaplasia. We have reported that acid and bile salts induce DNA damage in Barrett's cells. Bile salts also cause NF-κB activation in Barrett's cells, enabling them to resist apoptosis in the setting of DNA damage, and likely contributing to carcinogenesis. Oral treatment with ursodeoxycholic acid prevents the esophageal DNA damage and NF-κB activation induced by toxic bile acids. Altering bile acid composition might be another approach to cancer prevention. PMID:27331918

From Reflux Esophagitis to Esophageal Adenocarcinoma.

PubMed

Souza, Rhonda F

Reflux esophagitis causes Barrett's metaplasia, an abnormal esophageal mucosa predisposed to adenocarcinoma. Medical therapy for reflux esophagitis focuses on decreasing gastric acid production with proton pump inhibitors. We have reported that reflux esophagitis in a rat model develops from a cytokine-mediated inflammatory injury, not from a caustic chemical (acid) injury. In this model, refluxed acid and bile stimulate the release of inflammatory cytokines from esophageal squamous cells, recruiting lymphocytes first to the submucosa and later to the luminal surface. Emerging studies on acute reflux esophagitis in humans support this new concept, suggesting that reflux-induced cytokine release may be a future target for medical therapies. Sometimes, reflux esophagitis heals with Barrett's metaplasia, a process facilitated by reflux-related nitric oxide (NO) production and Sonic Hedgehog (Hh) secretion by squamous cells. We have shown that NO reduces expression of genes that promote a squamous cell phenotype, while Hh signaling induces genes that mediate the development of the columnar cell phenotypes of Barrett's metaplasia. Agents targeting esophageal NO production or Hh signaling conceivably could prevent the development of Barrett's esophagus. Persistent reflux promotes cancer in Barrett's metaplasia. We have reported that acid and bile salts induce DNA damage in Barrett's cells. Bile salts also cause NF-x03BA;B activation in Barrett's cells, enabling them to resist apoptosis in the setting of DNA damage and likely contributing to carcinogenesis. Oral treatment with ursodeoxycholic acid prevents the esophageal DNA damage and NF-x03BA;B activation induced by toxic bile acids. Altering bile acid composition might be another approach to cancer prevention. © 2016 S. Karger AG, Basel.

Computational modeling and molecular imprinting for the development of acrylic polymers with high affinity for bile salts.

PubMed

Yañez, Fernando; Chianella, Iva; Piletsky, Sergey A; Concheiro, Angel; Alvarez-Lorenzo, Carmen

2010-02-05

This work has focused on the rational development of polymers capable of acting as traps of bile salts. Computational modeling was combined with molecular imprinting technology to obtain networks with high affinity for cholate salts in aqueous medium. The screening of a virtual library of 18 monomers, which are commonly used for imprinted networks, identified N-(3-aminopropyl)-methacrylate hydrochloride (APMA.HCl), N,N-diethylamino ethyl methacrylate (DEAEM) and ethyleneglycol methacrylate phosphate (EGMP) as suitable functional monomers with medium-to-high affinity for cholic acid. The polymers were prepared with a fix cholic acid:functional monomer mole ratio of 1:4, but with various cross-linking densities. Compared to polymers prepared without functional monomer, both imprinted and non-imprinted microparticles showed a high capability to remove sodium cholate from aqueous medium. High affinity APMA-based particles even resembled the performance of commercially available cholesterol-lowering granules. The imprinting effect was evident in most of the networks prepared, showing that computational modeling and molecular imprinting can act synergistically to improve the performance of certain polymers. Nevertheless, both the imprinted and non-imprinted networks prepared with the best monomer (APMA.HCl) identified by the modeling demonstrated such high affinity for the template that the imprinting effect was less important. The fitting of adsorption isotherms to the Freundlich model indicated that, in general, imprinting increases the population of high affinity binding sites, except when the affinity of the functional monomer for the target molecule is already very high. The cross-linking density was confirmed as a key parameter that determines the accessibility of the binding points to sodium cholate. Materials prepared with 9% mol APMA and 91% mol cross-linker showed enough affinity to achieve binding levels of up to 0.4 mmol g(-1) (i.e., 170 mg g(-1)) under flow (1 mL min(-1)) of 0.2 mM sodium cholate solution. Copyright 2009 Elsevier B.V. All rights reserved.

Crystal Structure of Human Liver [delta][superscript 4]-3-Ketosteroid 5[beta]-Reductase (AKR1D1) and Implications for Substrate Binding and Catalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Costanzo, Luigi; Drury, Jason E.; Penning, Trevor M.

2008-07-15

AKR1D1 (steroid 5{beta}-reductase) reduces all {Delta}{sup 4}-3-ketosteroids to form 5{beta}-dihydrosteroids, a first step in the clearance of steroid hormones and an essential step in the synthesis of all bile acids. The reduction of the carbon-carbon double bond in an {alpha}{beta}-unsaturated ketone by 5{beta}-reductase is a unique reaction in steroid enzymology because hydride transfer from NADPH to the {beta}-face of a {Delta}{sup 4}-3-ketosteroid yields a cis-A/B-ring configuration with an {approx}90{sup o} bend in steroid structure. Here, we report the first x-ray crystal structure of a mammalian steroid hormone carbon-carbon double bond reductase, human {Delta}{sup 4}-3-ketosteroid 5{beta}-reductase (AKR1D1), and its complexes withmore » intact substrates. We have determined the structures of AKR1D1 complexes with NADP{sup +} at 1.79- and 1.35-{angstrom} resolution (HEPES bound in the active site), NADP{sup +} and cortisone at 1.90-{angstrom} resolution, NADP{sup +} and progesterone at 2.03-{angstrom} resolution, and NADP{sup +} and testosterone at 1.62-{angstrom} resolution. Complexes with cortisone and progesterone reveal productive substrate binding orientations based on the proximity of each steroid carbon-carbon double bond to the re-face of the nicotinamide ring of NADP{sup +}. This orientation would permit 4-pro-(R)-hydride transfer from NADPH. Each steroid carbonyl accepts hydrogen bonds from catalytic residues Tyr{sup 58} and Glu{sup 120}. The Y58F and E120A mutants are devoid of activity, supporting a role for this dyad in the catalytic mechanism. Intriguingly, testosterone binds nonproductively, thereby rationalizing the substrate inhibition observed with this particular steroid. The locations of disease-linked mutations thought to be responsible for bile acid deficiency are also revealed.« less

Crystal Structure of Human Liver delta {4}-3-Ketosteroid 5 beta-Reductase (AKR1D1) and Implications for Substrate Binding and Catalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Costanzo,L.; Drury, J.; Penning, T.

2008-01-01

AKR1D1 (steroid 5{beta}-reductase) reduces all 4-3-ketosteroids to form 5{beta}-dihydrosteroids, a first step in the clearance of steroid hormones and an essential step in the synthesis of all bile acids. The reduction of the carbon-carbon double bond in an a,{beta}-unsaturated ketone by 5{beta}-reductase is a unique reaction in steroid enzymology because hydride transfer from NADPH to the {beta}-face of a 4-3-ketosteroid yields a cis-A/B-ring configuration with an {approx}90 bend in steroid structure. Here, we report the first x-ray crystal structure of a mammalian steroid hormone carbon-carbon double bond reductase, human 4-3-ketosteroid 5{beta}-reductase (AKR1D1), and its complexes with intact substrates. We havemore » determined the structures of AKR1D1 complexes with NADP+ at 1.79- and 1.35- Angstroms resolution (HEPES bound in the active site), NADP+ and cortisone at 1.90- Angstroms resolution, NADP+ and progesterone at 2.03- Angstroms resolution, and NADP+ and testosterone at 1.62- Angstroms resolution. Complexes with cortisone and progesterone reveal productive substrate binding orientations based on the proximity of each steroid carbon-carbon double bond to the re-face of the nicotinamide ring of NADP+. This orientation would permit 4-pro-(R)-hydride transfer from NADPH. Each steroid carbonyl accepts hydrogen bonds from catalytic residues Tyr58 and Glu120. The Y58F and E120A mutants are devoid of activity, supporting a role for this dyad in the catalytic mechanism. Intriguingly, testosterone binds nonproductively, thereby rationalizing the substrate inhibition observed with this particular steroid. The locations of disease-linked mutations thought to be responsible for bile acid deficiency are also revealed.« less

Bile acids, neutral steroids, and bacteria in feces as affected by a mixed, a lacto-ovovegetarian, and a vegan diet.

PubMed

van Faassen, A; Bol, J; van Dokkum, W; Pikaar, N A; Ockhuizen, T; Hermus, R J

1987-12-01

In a metabolic ward 12 healthy male subjects consumed mixed Western (M), lacto-ovovegetarian (L), and vegan (V) diets in a randomized order for 20 d each. The concentrations of deoxycholic acid, isolithocholic acid, and total bile acids in 4-d composites of feces on the L and V diets were significantly lower than on the M diet. The chenodeoxycholic-to-isolithocholic plus lithocholic acid ratio was significantly higher on the V diet. The concentrations of coprostanol and of coprostanol plus cholesterol were highest on M diet and lowest on V diet. The number of fecal lactobacilli and enterococci on the V diet was significantly lower than on the M or the L diets. This study showed a decrease in the concentration of fecal (secondary) bile acids by the L and the V diets and an alteration of the fecal flora composition by the V diet.

Independent Activation of Hepatitis B Virus Biosynthesis by Retinoids, Peroxisome Proliferators, and Bile Acids

PubMed Central

Reese, Vanessa C.; Oropeza, Claudia E.

2013-01-01

In the human hepatoma cell line HepG2, retinoic acid, clofibric acid, and bile acid treatment can only modestly increase hepatitis B virus (HBV) biosynthesis. Utilizing the human embryonic kidney cell line 293T, it was possible to demonstrate that the retinoid X receptor α (RXRα) plus its ligand can support viral biosynthesis independently of additional nuclear receptors. In addition, RXRα/peroxisome proliferator-activated receptor α (PPARα) and RXRα/farnesoid X receptor α (FXRα) heterodimeric nuclear receptors can also mediate ligand-dependent HBV transcription and replication when activated by clofibric acid and bile acid, respectively, independently of a requirement for the ligand-dependent activation of RXRα. These observations indicate that there are at least three possible modes of ligand-mediated activation of HBV transcription and replication existing within hepatocytes, suggesting that multiple independent mechanisms control viral production in the livers of infected individuals. PMID:23135717

A Review of the Diagnosis and Treatment of Ochratoxin A Inhalational Exposure Associated with Human Illness and Kidney Disease including Focal Segmental Glomerulosclerosis

PubMed Central

Hope, Janette H.; Hope, Bradley E.

2012-01-01

Ochratoxin A (OTA) exposure via ingestion and inhalation has been described in the literature to cause kidney disease in both animals and humans. This paper reviews Ochratoxin A and its relationship to human health and kidney disease with a focus on a possible association with focal segmental glomerulosclerosis (FSGS) in humans. Prevention and treatment strategies for OTA-induced illness are also discussed, including cholestyramine, a bile-acid-binding resin used as a sequestrant to reduce the enterohepatic recirculation of OTA. PMID:22253638

Is bile acid malabsorption underdiagnosed? An evaluation of accuracy of diagnosis by measurement of SeHCAT retention.

PubMed Central

Merrick, M V; Eastwood, M A; Ford, M J

1985-01-01

The cause of intractable chronic diarrhoea was found to be malabsorption of bile acid in five out of 42 patients thought to have the irritable bowel syndrome, six out of 29 patients with persistent diarrhoea after surgery for peptic ulcer, 23 who had undergone small bowel resection, and two others. Specific treatment brought symptomatic relief. The diagnosis was established by measuring the proportion of SeHCAT, a synthetic bile salt, retained one week after oral administration of a tracer dose of less than 100 micrograms of the compound labelled with 40 kBq (1 microCi) of selenium-75. These results indicate that malabsorption of bile acid is a more common cause of chronic diarrhoea than is generally appreciated. Measurement of retention of SeHCAT is a simple, accurate, and acceptable means of establishing the diagnosis of this debilitating but treatable condition. PMID:3918708

Is bile acid malabsorption underdiagnosed? An evaluation of accuracy of diagnosis by measurement of SeHCAT retention.

PubMed

Merrick, M V; Eastwood, M A; Ford, M J

1985-03-02

The cause of intractable chronic diarrhoea was found to be malabsorption of bile acid in five out of 42 patients thought to have the irritable bowel syndrome, six out of 29 patients with persistent diarrhoea after surgery for peptic ulcer, 23 who had undergone small bowel resection, and two others. Specific treatment brought symptomatic relief. The diagnosis was established by measuring the proportion of SeHCAT, a synthetic bile salt, retained one week after oral administration of a tracer dose of less than 100 micrograms of the compound labelled with 40 kBq (1 microCi) of selenium-75. These results indicate that malabsorption of bile acid is a more common cause of chronic diarrhoea than is generally appreciated. Measurement of retention of SeHCAT is a simple, accurate, and acceptable means of establishing the diagnosis of this debilitating but treatable condition.

Guar gum and bile: effects on postprandial gallbladder contraction and on serum bile acids in man.

PubMed

Hansen, W E; Maurer, H; Vollmar, J; Bräuning, C

1983-08-01

In a randomized cross-over study, 10 healthy volunteers received a fiber-depleted liquid mixed meal alone and, exactly 7 days apart, a combination with 15 g guar gum. Addition of the dietary fiber inhibited emptying of the gall bladder after 30 min to 7 (5-10) ml instead of 4 (3-6) ml (p less than 0.05) and delayed its refilling. Also the postprandial increase in conjugated serum bile acids was prevented by guar gum. The maximal postprandial blood glucose 30 min after ingestion of the meal was reduced from 120 (117-135) mg/dl to 110 (105-119) mg/dl (p less than or equal to 0.05) by guar gum. Serum insulin levels were unaffected by guar gum.--Our data suggest that the addition of guar gum to meals affects enterohepatic circulation of bile acids as well as digestion of carbohydrates.

Ursodeoxycholic acid in chronic liver disease.

PubMed Central

de Caestecker, J S; Jazrawi, R P; Petroni, M L; Northfield, T C

1991-01-01

The hydrophilic bile acid ursodeoxycholic acid has recently been shown to reduce biochemical markers of both cholestasis and hepatocellular damage in patients with chronic liver diseases. The most compelling evidence available is for chronic cholestatic liver diseases, in particular primary biliary cirrhosis, primary sclerosing cholangitis, and cholestasis associated with cystic fibrosis. The effects may be less beneficial in patients with advanced liver disease from these conditions. Data from placebo controlled trials are now available in support of earlier uncontrolled observations, but it is not yet clear whether short term benefit results in an improvement in longterm prognosis. The mechanism of action of the compound seems to reside in its displacement of toxic hydrophobic bile acids from both the bile acid pool and hepatocellular membranes. There may be an independent effect on bile flow, which could be of particular importance in cystic fibrosis, and possibly an effect on the immune system. Ursodeoxycholic acid should now be regarded as occupying a central place in the medical management of chronic cholestatic liver diseases, in particular primary biliary cirrhosis, because it improves cholestasis and reduces hepatocellular damage and it is not toxic. Research should now be targeted on whether treatment with ursodeoxycholic acid, initiated early in cholestatic liver conditions, improves the long-term outcome. PMID:1916492

Transporter-targeted cholic acid-cytarabine conjugates for improved oral absorption.

PubMed

Zhang, Dong; Li, Dongpo; Shang, Lei; He, Zhonggui; Sun, Jin

2016-09-10

Cytarabine has a poor oral absorption due to its rapid deamination and poor membrane permeability. Bile acid transporters are highly expressed both in enterocytes and hepatocytes and to increase the oral bioavailability and investigate the potential application of cytarabine for liver cancers, a transporter- recognizing prodrug strategy was applied to design and synthesize four conjugates of cytarabine with cholic acid (CA), chenodeoxycholic acid (CDCA), hyodeoxycholic acid (HDCA) and ursodeoxycholic acid (UDCA). The anticancer activities against HepG2 cells were evaluated by MTT assay and the role of bile acid transporters during cellular transport was investigated in a competitive inhibition experiment. The in vitro and in vivo metabolic stabilities of these conjugates were studied in rat plasma and liver homogenates. Finally, an oral bioavailability study was conducted in rats. All the cholic acid-cytarabine conjugates (40μM) showed potent antiproliferative activities (up to 70%) against HepG2 cells after incubation for 48h. The addition of bile acids could markedly reduce the antitumor activities of these conjugates. The N(4)-ursodeoxycholic acid conjugate of cytarabine (compound 5) exhibited optimal stability (t1/2=90min) in vitro and a 3.9-fold prolonged half-life of cytarabine in vivo. More importantly, compound 5 increased the oral bioavailability 2-fold compared with cytarabine. The results of the present study suggest that the prodrug strategy based on the bile acid transporters is suitable for improving the oral absorption and the clinical application of cytarabine. Copyright © 2016 Elsevier B.V. All rights reserved.

Ursodeoxycholic Acid in Treatment of Non-cholestatic Liver Diseases: A Systematic Review

PubMed Central

Reardon, Jillian; Hussaini, Trana; Alsahafi, Majid; Azalgara, Vladimir Marquez; Erb, Siegfried R.; Partovi, Nilufar; Yoshida, Eric M.

2016-01-01

Abstract Aims: To systematically evaluate the literature for evidence to support the use of bile acids in non-cholestatic liver conditions. Methods: Searches were conducted on the databases of Medline (1948-March 31, 2015), Embase (1980-March 31, 2015) and the Cochrane Central Register of Controlled Trials, and on Google and Google Scholar to identify articles describing ursodeoxycholic acid (UDCA) and its derivatives for non-cholestatic hepatic indications. Combinations of the following search terms were used: ursodeoxycholic acid, ursodiol, bile acids and/or salts, non alcoholic fatty liver, non alcoholic steatohepatitis, fatty liver, alcoholic hepatitis, alcohol, liver disease, autoimmune, autoimmune hepatitis, liver transplant, liver graft, transplant rejection, graft rejection, ischemic reperfusion injury, reperfusion injury, hepatitis B, hepatitis C, viral hepatitis, chronic hepatitis, acute hepatitis, transaminases, alanine transaminase, liver enzymes, aspartate aminotransferase, gamma-glutamyl transferase, gamma-glutamyl transpeptidase, bilirubin, alkaline phosphatase. No search limits were applied. Additionally, references of the included studies were reviewed to identify additional articles. Results: The literature search yielded articles meeting inclusion criteria for the following indications: non-alcoholic fatty liver disease (n = 5); alcoholic liver disease (n = 2); autoimmune hepatitis (n = 6), liver transplant (n = 2) and viral hepatitis (n = 9). Bile acid use was associated with improved normalization of liver biochemistry in non-alcoholic fatty liver disease, autoimmune hepatitis and hepatitis B and C infections. In contrast, liver biochemistry normalization was inconsistent in alcoholic liver disease and liver transplantation. The majority of studies reviewed showed that normalization of liver biochemistry did not correlate to improvement in histologic disease. In the prospective trials reviewed, adverse effects associated with the bile acids were limited to minor gastrointestinal complaints (most often, diarrhea) and did not occur at increased frequency as compared to controls. As administration of bile acids was often limited to durations of 12 months or less, long-term side effects for non-cholestatic indications cannot be excluded. Conclusions: Based on the available literature, bile acids cannot be widely recommended for non-cholestatic liver diseases at present. PMID:27777888

Thin-layer chromatographic separation of conjugates of ursodeoxycholic acid from those of litho-, chenodeoxy-, deoxy-, and cholic acids.

PubMed

Batta, A K; Shefer, S; Salen, G

1981-05-01

Separation of the glycine and taurine conjugates of ursodeoxycholic acid from those of lithocholic acid, chenodeoxycholic acid, deoxycholic acid, and cholic acid by thin-layer chromatography is described. Thus, on running a silica gel G plate first in a solvent system of n-butanol-water 20:3 and then in a second solvent system of chloroform-isopropanol-acetic acid-water 30:20:4:1, all the above-mentioned conjugated bile acids are separated from one another. The application of this method to study the change in the biliary bile acid conjugation pattern in ursodeoxycholic acid-fed gallstone patients is described.

A single-component multidrug transporter of the major facilitator superfamily is part of a network that protects E scherichia coli from bile salt stress

PubMed Central

Paul, Stephanie; Alegre, Kamela O; Holdsworth, Scarlett R; Rice, Matthew; Brown, James A; McVeigh, Paul; Kelly, Sharon M; Law, Christopher J

2014-01-01

Resistance to high concentrations of bile salts in the human intestinal tract is vital for the survival of enteric bacteria such as E scherichia coli. Although the tripartite AcrAB–TolC efflux system plays a significant role in this resistance, it is purported that other efflux pumps must also be involved. We provide evidence from a comprehensive suite of experiments performed at two different pH values (7.2 and 6.0) that reflect pH conditions that E . coli may encounter in human gut that MdtM, a single-component multidrug resistance transporter of the major facilitator superfamily, functions in bile salt resistance in E . coli by catalysing secondary active transport of bile salts out of the cell cytoplasm. Furthermore, assays performed on a chromosomal ΔacrB mutant transformed with multicopy plasmid encoding MdtM suggested a functional synergism between the single-component MdtM transporter and the tripartite AcrAB–TolC system that results in a multiplicative effect on resistance. Substrate binding experiments performed on purified MdtM demonstrated that the transporter binds to cholate and deoxycholate with micromolar affinity, and transport assays performed on inverted vesicles confirmed the capacity of MdtM to catalyse electrogenic bile salt/H+ antiport. PMID:24684269

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galatola, G.; Jazrawi, R.P.; Bridges, C.

/sup 75/Se-homocholic acid-taurine (/sup 75/SeHCAT) is the first available gamma-labeled bile acid, and should therefore be handled more efficiently and specifically by the liver than previous hepatoscintigraphic agents. We have measured serum and hepatic kinetics for /sup 75/SeHCAT, and compared them with those for the conventional hepatobiliary scintigraphic agent 99mTc-hepatoiminodiacetic acid, and with serum kinetics for the corresponding natural bile acid, (/sup 14/C)cholic acid-taurine. We used a dynamic scintigraphic technique and serial blood sampling in 8 subjects. Initial hepatic uptake rate was identical to initial serum disappearance rate (14% dose/min) for /sup 75/SeHCAT, but significantly lower for 99mTc-hepatoiminodiacetic acid (6%more » vs. 14% dose/min, p less than 0.001). Hepatic transit time was shorter for /sup 75/SeHCAT (13 min vs. 22 min, p less than 0.02), net hepatic excretory rate was more rapid (1.4% vs. 0.8% dose/min, p less than 0.001), and urinary excretion was lower (1.0% vs. 9.0% dose, p less than 0.001). Initial and late-plasma disappearance rates were significantly lower for /sup 75/SeHCAT (14.3% and 1.5% dose/min) than for (/sup 14/C)cholic acid-taurine (21.3% and 2.8% dose/min, respectively), and plasma clearance was also lower (2/sup 75/ vs. 670 ml/min). In vitro, /sup 75/SeHCAT was bound to serum proteins more completely than (/sup 14/C)cholic acid-taurine (90.4% vs. 86.5%, p less than 0.005). We conclude that /sup 75/SeHCAT provides a hepatoscintigraphic agent that is handled more efficiently and specifically by the liver than the conventionally used agent 99mTc-hepatoiminodiacetic acid. It is not cleared from the serum as rapidly as (/sup 14/C)cholic acid-taurine, probably due to its stronger protein binding. The clinical value of /sup 75/SeHCAT in assessing liver disease should be investigated.« less

Bile system morphogenesis defects and liver dysfunction upon targeted deletion of HNF1beta.

PubMed

Coffinier, Catherine; Gresh, Lionel; Fiette, Laurence; Tronche, François; Schütz, Günther; Babinet, Charles; Pontoglio, Marco; Yaniv, Moshe; Barra, Jacqueline

2002-04-01

The inactivation of the Hnf1beta gene identified an essential role in epithelial differentiation of the visceral endoderm and resulted in early embryonic death. In the present study, we have specifically inactivated this gene in hepatocytes and bile duct cells using the Cre/loxP system. Mutant animals exhibited severe jaundice caused by abnormalities of the gallbladder and intrahepatic bile ducts (IHBD). The paucity of small IHBD was linked to a failure in the organization of duct structures during liver organogenesis, suggesting an essential function of Hnf1b in bile duct morphogenesis. Mutant mice also lacked interlobular arteries. As HNF1beta is not expressed in these cells, it further emphasizes the link between arterial and biliary formation. Hepatocyte metabolism was also affected and we identified hepatocyte-specific HNF1beta target genes involved in bile acids sensing and in fatty acid oxidation.

Effect of human pancreatic juice and bile on the tensile strength of suture materials.

PubMed

Muftuoglu, M A Tolga; Ozkan, Erkan; Saglam, Abdullah

2004-08-01

Several suture materials are used for pancreatojejunal anastomosis. In this study, we tested the durability of these suture materials in human pancreatic juice and bile. Plain and chromic catgut, polyglactin 910, polyglycolic acid, polydioxanone, polypropylene, and silk sutures were incubated in pancreatic juice and bile that was collected from patients. Fifteen samples of each type of suture material were placed in human juices for 1, 3, and 7 days. Tensile strengths were measured with a tensionmeter. Plain and chromic catgut disintegrated in pancreatic juice and pancreatic juice plus bile mixture. Polyglycolic acid and polyglactin 910 suture materials were vulnerable to pancreatic juice within 7 days. Polydioxanone retained most of its initial strength in pancreatic juice and bile. Polypropylene and silk retained 84% and 92% of their initial strength, respectively. We found that polidioxanone was the strongest suture material in pancreatic juice.

Effects of endogenous hydrogen peroxide and glutathione on the stability of arsenic metabolites in rat bile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, Yayoi; Hirano, Seishiro

2008-10-01

Trivalent arsenicals such as arsenite (iAs{sup III}), monomethylarsonous acid (MMA{sup III}) and dimethylarsinous acid (DMA{sup III}) are more toxic than analogous pentavalent compounds such as arsenate (iAs{sup V}), monomethylarsonic acid (MMA{sup V}) and dimethylarsinic acid (DMA{sup V}). It has been reported that arsenic-glutathione (As-GSH) complexes such as arsenic triglutathione (ATG) and methylarsenic diglutathione (MADG) are major metabolites in rat bile following intravenous administration of iAs{sup III}. Recently, we have shown that both ATG and MADG are unstable and easily hydrolyzed to iAs{sup III} and MMA{sup III}, respectively, and that MMA{sup III} is oxidized to MMA{sup V} in bile. In themore » present study we report the effects of H{sub 2}O{sub 2} and GSH on the stability of As-GSH complexes in rat bile. Male SD rats were injected intravenously with saline or iAs{sup III} at a dose of 0.2 or 2.0 mg As/kg body weight, and bile fluid was collected on ice for 30 min. To estimate the stability of As-GSH complexes in bile, ATG or MADG was added to untreated, heat-treated, catalase-treated, or dialyzed bile, and then incubated at 37 deg. C for 10 min. Concentrations of biliary H{sub 2}O{sub 2} and GSH in the higher dose group were 12.6- and 4.5-times higher than the control value, respectively. Exogenously added trivalent arsenicals were oxidized to pentavalent arsenicals in the bile depending on the biliary concentration of H{sub 2}O{sub 2}. Both catalase and dialysis prevented oxidation of trivalent arsenicals to the corresponding pentavalent compounds. Exogenously added GSH stabilized As-GSH complexes in bile. These results suggest that H{sub 2}O{sub 2} converts trivalent arsenicals to less toxic pentavalent arsenicals, whereas GSH prevents hydrolysis of As-GSH complexes and the generation of unconjugated toxic trivalent arsenicals.« less

Inhibition of intestinal bile acid absorption improves cholestatic liver and bile duct injury in a mouse model of sclerosing cholangitis.

PubMed

Baghdasaryan, Anna; Fuchs, Claudia D; Österreicher, Christoph H; Lemberger, Ursula J; Halilbasic, Emina; Påhlman, Ingrid; Graffner, Hans; Krones, Elisabeth; Fickert, Peter; Wahlström, Annika; Ståhlman, Marcus; Paumgartner, Gustav; Marschall, Hanns-Ulrich; Trauner, Michael

2016-03-01

Approximately 95% of bile acids (BAs) excreted into bile are reabsorbed in the gut and circulate back to the liver for further biliary secretion. Therefore, pharmacological inhibition of the ileal apical sodium-dependent BA transporter (ASBT/SLC10A2) may protect against BA-mediated cholestatic liver and bile duct injury. Eight week old Mdr2(-/-) (Abcb4(-/-)) mice (model of cholestatic liver injury and sclerosing cholangitis) received either a diet supplemented with A4250 (0.01% w/w) - a highly potent and selective ASBT inhibitor - or a chow diet. Liver injury was assessed biochemically and histologically after 4weeks of A4250 treatment. Expression profiles of genes involved in BA homeostasis, inflammation and fibrosis were assessed via RT-PCR from liver and ileum homogenates. Intestinal inflammation was assessed by RNA expression profiling and immunohistochemistry. Bile flow and composition, as well as biliary and fecal BA profiles were analyzed after 1week of ASBT inhibitor feeding. A4250 improved sclerosing cholangitis in Mdr2(-/-) mice and significantly reduced serum alanine aminotransferase, alkaline phosphatase and BAs levels, hepatic expression of pro-inflammatory (Tnf-α, Vcam1, Mcp-1) and pro-fibrogenic (Col1a1, Col1a2) genes and bile duct proliferation (mRNA and immunohistochemistry for cytokeratin 19 (CK19)). Furthermore, A4250 significantly reduced bile flow and biliary BA output, which correlated with reduced Bsep transcription, while Ntcp and Cyp7a1 were induced. Importantly A4250 significantly reduced biliary BA secretion but preserved HCO3(-) and biliary phospholipid secretion resulting in an increased HCO3(-)/BA and PL/BA ratio. In addition, A4250 profoundly increased fecal BA excretion without causing diarrhea and altered BA pool composition, resulting in diminished concentrations of primary BAs tauro-β-muricholic acid and taurocholic acid. Pharmacological ASBT inhibition attenuates cholestatic liver and bile duct injury by reducing biliary BA concentrations in mice. Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

The study and application of four kinds of organic ion-selective microsensors

NASA Astrophysics Data System (ADS)

Yu, Bi; Zheng, Xiao; Feng, Chu; Hong, Wen-Bing; Liu, Jun-Tao; Wang, Ru-Jiang

1991-09-01

Four kinds of organic ion-selective microelectrodes (two barrels, tip diameter 0.1-0.5 micron) have been developed for the measurement of acetylcholine, histamine, serotonin, and bile acid. Physiological and pathological models on the cellular or sub-cellular level have been established for the purpose of basic and clinical pharmacological research, treatment or diagnosis of certain diseases. The acetylcholine sensitive microelectrode has been applied to the study of acetylcholine activity in single erythrocytes of normal human subjects and patients suffering from manic depressive disorders. The bile acid selective microelectrode has been used for the direct measurement of intracellular bile acid activities both in colorectal cancer and colorectal mucosa in living condition.

Protective effects of calycosin against CCl4-induced liver injury with activation of FXR and STAT3 in mice.

PubMed

Chen, Xinli; Meng, Qiang; Wang, Changyuan; Liu, Qi; Sun, Huijun; Huo, Xiaokui; Sun, Pengyuan; Yang, Xiaobo; Peng, Jinyong; Liu, Kexin

2015-02-01

Investigating the hepatoprotective effect of calycosin against acute liver injury in association with FXR activation and STAT3 phosphorylation. The acute liver injury model was established by intraperitoneal injection of CCl4 in C57BL/6 mice. Serum alanine aminotransferase, aspartate aminotransferase, HE staining and TUNEL assay were used to identify the amelioration of the liver histopathological changes and hepatocytes apoptosis after calycosin treatment. ELISA kit and 5-bromo-2-deoxyuridine immunohistochemistry were used to measure the liver bile acid concentration and hepatocyte mitotic rate in vivo. The relation between calycosin and activation of FXR and STAT3 was comfirmed using the Luciferase assay, Molecular docking, Real-time PCR and Western Blot in vitro. The liver histopathological changes, hepatocytes apoptosis, liver bile acid overload and hepatocyte mitosis showed significant changes after calycosin treatment. Calycosin promoted the expression of FXR target genes such as FoxM1B and SHP but the effect was reversed by FXR suppressor guggulsterone. Molecular docking results indicated that calycosin could be embedded into the binding pocket of FXR, thereby increasing the expressions of STAT3 tyrosine phosphorylation and its target genes, Bcl-xl and SOCS3. Calycosin plays a critical role in hepatoprotection against liver injury in association with FXR activation and STAT3 phosphorylation.

The effect of prebiotics on production of antimicrobial compounds, resistance to growth at low pH and in the presence of bile, and adhesion of probiotic cells to intestinal mucus.

PubMed

Brink, M; Todorov, S D; Martin, J H; Senekal, M; Dicks, L M T

2006-04-01

Screening of five bile salt-resistant and low pH-tolerant lactic acid bacteria for inhibitory activity against lactic acid bacteria and bacterial strains isolated from the faeces of children with HIV/AIDS. Determining the effect of prebiotics and soy milk-base on cell viability and adhesion of cells to intestinal mucus. Lactobacillus plantarum 423, Lactobacillus casei LHS, Lactobacillus salivarius 241, Lactobacillus curvatus DF 38 and Pediococcus pentosaceus 34 produced the highest level of antimicrobial activity (12,800 AU ml(-1)) when grown in MRS broth supplemented with 2% (m/v) dextrose. Growth in the presence of Raftilose Synergy1, Raftilose L95 and Raftiline GR did not lead to increased levels of antimicrobial activity. Cells grown in the presence of Raftilose Synergy1 took longer to adhere to intestinal mucus, whilst cells grown in the absence of prebiotics showed a linear rate of binding. A broad range of gram-positive and gram-negative bacteria were inhibited. Dextrose stimulated the production of antimicrobial compounds. Adhesion to intestinal mucus did not increase with the addition of prebiotics. The strains may be incorporated in food supplements for HIV/AIDS patients suffering from gastro-intestinal disorders.

Association between bile acid turnover and osteoporosis in postmenopausal women.

PubMed

Hanly, Ruth; Ryan, Nicola; Snelling, Hayley; Walker-Bone, Karen; Dizdarevic, Sabina; Peters, A Michael

2013-06-01

The intestinal absorption of vitamin D is linked to bile acid absorption. This link may be abnormal in patients with osteoporosis. The aim of this study was to investigate a possible relation between osteoporosis and bile acid turnover, measured as whole-body Se-75-HCAT retention (WBR), in postmenopausal women. Whole-body counts were recorded using an uncollimated gamma camera 3 h and 7 days after oral administration of Se-75-homocholic acid taurine (Se-75-HCAT) in 16 women aged 58-85 years with dual-photon X-ray absorptiometry (DEXA)-proven osteoporosis. WBR was expressed as physical decay-corrected counts at 7 days as a percentage of the counts at 3 h. Seven patients had unexplained diarrhoea. Six patients (five with diarrhoea) had WBR less than 19%. There was a significant difference in DEXA t-score between women with and without diarrhoea (P<0.02). There was a significant negative correlation (R s=-0.58; P<0.02) between WBR and alcohol consumption rated on a three-point scale: <1, 2-7 and >7 U/week. Our results indicate an association between osteoporosis and diarrhoea that may be the result of abnormal bile acid turnover. The role of alcohol requires further investigation.

Prospective evaluation of ursodeoxycholic acid withdrawal in patients with primary sclerosing cholangitis.

PubMed

Wunsch, Ewa; Trottier, Jocelyn; Milkiewicz, Malgorzata; Raszeja-Wyszomirska, Joanna; Hirschfield, Gideon M; Barbier, Olivier; Milkiewicz, Piotr

2014-09-01

Ursodeoxycholic acid (UDCA) is no longer recommended for management of adult patients with primary sclerosing cholangitis (PSC). We undertook a prospective evaluation of UDCA withdrawal in a group of consecutive patients with PSC. Twenty six patients, all treated with UDCA (dose range: 10-15 mg/kg/day) were included. Paired blood samples for liver biochemistry, bile acids, and fibroblast growth factor 19 (FGF19) were collected before UDCA withdrawal and 3 months later. Liquid chromatography/tandem mass spectrometry was used for quantification of 29 plasma bile acid metabolites. Pruritus and health-related quality of life (HRQoL) were assessed with a 10-point numeric rating scale, the Medical Outcomes Study Short Form-36 (SF-36), and PBC-40 questionnaires. UDCA withdrawal resulted in a significant deterioration in liver biochemistry (increase of alkaline phosphatase of 75.6%; P<0.0001; gamma-glutamyl transpeptidase of 117.9%, P<0.0001; bilirubin of 50.0%, P<0.001; alanine aminotransferase of 63.9%, P<0.005; and aspartate aminotransferase of 45.0%, P<0.005) and increase of Mayo Risk Score for PSC (change from baseline of +0.5 point; P<0.003). Bile acid analysis revealed a significant decrease in lithocholic acid and its derivatives after UDCA withdrawal, but no effect on concentrations of primary bile acids aside from an increased accumulation of their taurine conjugates. After UDCA removal cholestatic parameters, taurine species of cholic acid and chenodeoxycholic acid correlated with serum FGF19 levels. No significant effect on HRQoL after UDCA withdrawal was observed; however, 42% of patients reported a deterioration in their pruritus. At 3 months, discontinuation of UDCA in patients with PSC causes significant deterioration in liver biochemistry and influences concentrations of bile acid metabolites. A proportion of patients report increased pruritus, but other short-term markers of quality of life are unaffected. © 2014 by the American Association for the Study of Liver Diseases.

Clinical application of a selenium (75Se)-labelled bile acid for the investigation of terminal ileal function.

PubMed

Nyhlin, H; Brydon, G; Danielsson, A; Westman, S

1984-08-01

With the introduction of a selenium bile acid SeHCAT (tauro-23-75Se-Selena-25 homocholic acid) a new and clinically valuable test for the functioning of the terminal ileum has been made available. Previous studies have shown that the test detects patients with bile acid malabsorption due to ileal disease. In this study SeHCAT retention was evaluated in nine patients with Crohn's disease and in seven healthy controls after intravenous administration of 0.15 MBq (4 muCi). A simple way of expressing the results is proposed. By using the calculated time required to eliminate 50% of the SeHCAT (WBR50), information is obtained as to the degree of terminal ileum malfunction regarding bile acid absorption. Accurate values seem to be achieved within 48 hours. As the SeHCAT is a gamma-ray emitter the dose retained could be measured by external counting. We suggest a practical design for the test using a simple scintillation spectro-photometer with a single detector in a low-background room. In patients and healthy controls the SeHCAT retention as calculated by WBR50 was 63 hrs (15-163) and 120 hrs (range 99-141), respectively. There was no overall relation between SeHCAT elimination and the intestinal transit time, although in the patient group a significant correlation was demonstrated, probably secondary to the impairment of the terminal ileum. A significant correlation was shown between the outcome of the test and the faecal excretion of total bile acids.

Phenotypic and genotypic characterization of lactic acid bacteria from traditional cheese in Khorramabad city of Iran with probiotic potential.

PubMed

Ghahremani, Enayat; Mardani, Mahnaz; Rezapour, Sadegh

2015-03-01

Lactic acid bacteria (LAB) with proteolitic activity are used as aromatic and antibacterial substances, cholesterol reduces, bile salt hydrolyses, and probiotic. The aims of this project were to isolate and identify natural LAB flora involved in traditional fermentation in cheeses of Khoramabad city and also to survey their probiotic potential. In order to achieve this goal, LAB were isolated and characterized using phenotypic and genotypic methods (PCR-sequencing); in the next stage, they were analyzed lowering cholesterol medium, hydrolysis of the bile, resistance to bile-resistant PH acidic stomach. At the end of the study, 88 cocci and 3 bacill were found: 58 Enterococcus faecium, 16 Enterococcus hirae, 5 Lactococcus lactis, 3 Lactobacillus plantarum, and 9 undetermined. The probiotic results of the bacteria had effects on the reduction of cholesterol, resistance to stomach acid, had relative antibacterial effects, and some strains had effects on hydrolyzing the bile. For further identification, the PCR method and the application of 16s-DNA-ITS genes and its sequencing were found useful. This study showed that lactic acid bacteria in the traditional cheese of the Khorramabad city have relative probiotic effect and that these lactic acid bacteria in fermented milk are suitable.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jazrawi, R.P.; Ferraris, R.; Bridges, C.

The apparent fractional turnover rate of the gamma-labeled bile acid analogue 75-selenohomocholic acid-taurine (75-SeHCAT) was assessed from decline in radioactivity over the gallbladder area on 4 successive days using a gamma-camera, and was compared in the same subjects with the fractional turnover rate of the corresponding natural bile acid, cholic acid-taurine, labeled with 14C ((14C)CAT) using the classical Lindstedt technique. Very similar results were obtained in 5 healthy individuals (coefficient of variation 4.8%, medians 0.35 and 0.34, respectively). By contrast, the fractional deconjugation rate assessed from zonal scanning of glycine- and taurine-conjugated bile acids on thin-layer chromatography was much lessmore » for 75-SeHCAT than for (14C)CAT (0.02 and 0.13, respectively; p less than 0.05). The fractional rate for deconjugation plus dehydroxylation was also determined by zonal scanning, and gave lower values for 75-SeHCAT than for (14C)CAT (0.02 and 0.12, respectively; p less than 0.05). There was a striking similarity between the fractional rate for deconjugation alone and that for deconjugation plus dehydroxylation for both bile acids in individual samples (r = 0.999, p less than 0.001), suggesting that these two processes might occur simultaneously and probably involve the same bacteria. We conclude that our scintiscanning technique provides an accurate, noninvasive method of measuring fractional turnover rate of a bile acid in humans, and that the finding that 75SeHCAT remains conjugated with taurine during enterohepatic recycling means that absorption should be specific for the ileal active transport site, thus rendering it an ideal substance for assessing ileal function.« less

The human apolipoprotein AV gene is regulated by peroxisome proliferator-activated receptor-alpha and contains a novel farnesoid X-activated receptor response element.

PubMed

Prieur, Xavier; Coste, Herve; Rodriguez, Joan C

2003-07-11

The newly identified apolipoprotein AV (apoAV) gene is a key player in determining plasma triglyceride concentrations. Because hypertriglyceridemia is a major independent risk factor in coronary artery disease, the understanding of the regulation of the expression of this gene is of considerable importance. We presently characterize the structure, the transcription start site, and the promoter of the human apoAV gene. Since the peroxisome proliferator-activated receptor-alpha (PPARalpha) and the farnesoid X-activated receptor (FXR) have been shown to modulate the expression of genes involved in triglyceride metabolism, we evaluated the potential role of these nuclear receptors in the regulation of apoAV transcription. Bile acids and FXR induced the apoAV gene promoter activity. 5'-Deletion, mutagenesis, and gel shift analysis identified a heretofore unknown element at positions -103/-84 consisting of an inverted repeat of two consensus receptor-binding hexads separated by 8 nucleotides (IR8), which was required for the response to bile acid-activated FXR. The isolated IR8 element conferred FXR responsiveness on a heterologous promoter. On the other hand, in apoAV-expressing human hepatic Hep3B cells, transfection of PPARalpha specifically enhanced apoAV promoter activity. By deletion, site-directed mutagenesis, and binding analysis, a PPARalpha response element located 271 bp upstream of the transcription start site was identified. Finally, treatment with a specific PPARalpha activator led to a significant induction of apoAV mRNA expression in hepatocytes. The identification of apoAV as a PPARalpha target gene has major implications with respect to mechanisms whereby pharmacological PPARalpha agonists may exert their beneficial hypotriglyceridemic actions.

Characterization and purification of bile salt hydrolase from Lactobacillus sp. strain 100-100

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundeen, S.G.; Savage, D.C.

1990-08-01

The authors have characterized and purified the bile salt hydrolase from Lactobacillus sp. strain 100-100. Bile salt hydrolase from cells of the strain was purified with column and high-performance liquid chromatography. The activity was assayed in whole cells and cell-free extracts with either a radiochemical assay involving ({sup 14}C)taurocholic acid or a nonradioactive assay involving trinitrobenzene sulfonate. The activity was detectable only in stationary-phase cells. Within 20 min after conjugated bile acids were added to stationary-phase cultures of strain 100-100, the activity in whole cells increased to levels three- to fivefold higher than in cells from cultures grown in mediummore » free of bile salts. In cell-free extracts, however, the activity was about equal whether or not the cells have been grown with bile salts present. When supernatant solutions from cultures grown in medium containing taurocholic acid were used to suspend cells grown in medium free of the bile salt, the bile salt hydrolase activity detected in whole cells increased two- to threefold. Two forms of the hydrolase were purified from the cells and designated hydrolases A and B. They eluted from anion-exchange high-performance liquid chromatography in two sets of fractions, A at 0.15 M NaCl and B at 0.18 M NaCl. Their apparent molecular weights in nondenaturing polyacrylamide gel electrophoresis were 115,000 and 105,000, respectively. However, discrepancies existed in the apparent molecular weights and number of peptides detected in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the two forms. Whether the enzyme exists in two forms in the cells remains to be determined.« less

75SeHCAT scan in bile acid malabsorption in chronic diarrhoea.

PubMed

Mena Bares, L M; Carmona Asenjo, E; García Sánchez, M V; Moreno Ortega, E; Maza Muret, F R; Guiote Moreno, M V; Santos Bueno, A M; Iglesias Flores, E; Benítez Cantero, J M; Vallejo Casas, J A

Chronic diarrhoea is a common entity in daily clinical practice and it leads to a loss in these patients quality of life. It may be the main symptom of multiple ethiologies including bile acid malabsorption (BAM) which has a comparable prevalence to celiac disease. The BAM results from imbalances in the homeostasis of bile acids in the enterohepatic circulation. It can be a consequence of ileal disease or ileal dysfunction (BAM type i), it can be considered idiopathic or primary (BAM type ii) or associated with other gastrointestinal entities (BAM type iii). Among the different diagnostic methods available, 75 SeHCAT study is the primary current method due to its sensitivity, specificity, safety and low cost. The main disadvantage is that it's not available in all countries, so other diagnostic methods have appeared, such as serum measurement of FGF19 and C4, however they are significantly more complex and costly. The first-line treatment of bile acid diarrhoea is bile acid sequestrant, such as cholestyramine, which can be difficult to administer due to its poor tolerability and gastrointestinal side effects. These are less prominent with newer agents such as colesevelam. In summary, the BAM is a common entity underdiagnosed and undertreated, so it is essential to establish a diagnosis algorithm of chronic diarrhoea in which the 75 SeHCAT study would be first or second line in the differential diagnosis of these patients. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

How bad is bile acid diarrhoea: an online survey of patient-reported symptoms and outcomes

PubMed Central

Bannaga, Ayman; Kelman, Lawrence; O'Connor, Michelle; Pitchford, Claire; Walters, Julian R F; Arasaradnam, Ramesh P

2017-01-01

Objectives Bile acid diarrhoea (BAD) is an underdiagnosed condition producing diarrhoea, urgency and fear of faecal incontinence. How patients experience these symptoms has not previously been studied. Bile Acid Malabsorption (BAM) Support UK was established in 2015 as a national charity with objectives including to provide details regarding how BAD affects patients, to improve earlier recognition and clinical management. Design, setting and main outcome A questionnaire was collected anonymously by BAM Support UK and the Bile Salt Malabsorption Facebook group over 4 weeks at the end of 2015. It comprised 56 questions and aimed to inform patients and clinicians about how BAD affects the respondents. Results The first 100 responses were analysed. 91% of the respondents reported a diagnosis of BAD. 58% of total respondents diagnosed following a Selenium-homocholic acid taurine scan, 69% were diagnosed by a gastroenterologist, with type 2 and 3 BAD comprising 38% and 37%, respectively, of total respondents. Symptoms had been experienced for more than 5 years before diagnosis in 44% of respondents. Following treatment, usually with bile acid sequestrants, 60% of participants reported improvement of diarrhoea and most reported their mental health has been positively impacted. Just over half of the cohort felt as though their symptoms had been dismissed during clinical consultations and 28% felt their GPs were unaware of BAD. Conclusions BAD requires more recognition by clinicians to address the current delays in diagnosis. Treatment improves physical and mental symptoms in the majority of participants. PMID:28123771

The efficacy of a low-fat diet to manage the symptoms of bile acid malabsorption - outcomes in patients previously treated for cancer.

PubMed

Jackson, Amy; Lalji, Amyn; Kabir, Mohammed; Muls, Ann; Gee, Caroline; Vyoral, Susan; Shaw, Clare; Andreyev, H Jervoise N

2017-10-01

Dietary fat ingestion triggers bile secretion into the gastrointestinal tract. Bile acid malabsorption affects >1% of the population, causing loose stool and other gastrointestinal symptoms. The diagnosis is frequently missed. Treatments are often considered ineffective. We evaluated low-fat diets for managing gastrointestinal symptoms in these patients. All patients reporting type 6 or 7 stool were offered a selenium-75 homocholic acid taurine (SeHCAT) scan. Prospective data in patients with 7-day scan retention <20% were analysed. -Patients requiring a bile acid sequestrant were given this before receiving dietary advice. Patients completed a 7-day food diary before dietetic consultations. Personalised dietary interventions, providing 20% of daily energy from fat, were prescribed. Symptoms were assessed using a modified gastrointestinal symptom rating scale questionnaire before and 4-12 weeks after dietary intervention. A total of 114 patients (49 male, median age 64 years, median body mass index 27 kg/m 2 ) were evaluated. 44% of these patients were taking colesevelam. After dietary intervention, there was statistically significant improvement in abdominal pain and nocturnal defecation (0.2% alpha, p=0.001). Improvement in bowel frequency, urgency, flatulence, belching, borborygmi and stool consistency were seen, but did not reach statistical significance (p≤0.004-0.031). Dietary intervention is an effective treatment option for patients with symptomatic bile acid malabsorption and should be routinely considered. © Royal College of Physicians 2017. All rights reserved.