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Sample records for bile acid conjugates

  1. Structural Determinants for Transport Across the Intestinal Bile Acid Transporter Using C-24 Bile Acid Conjugates

    PubMed Central

    Rais, Rana; Acharya, Chayan; MacKerell, Alexander D.; Polli, James E.

    2010-01-01

    The human apical sodium dependent bile acid transporter (hASBT) re-absorbs gram quantities of bile acid daily and is a potential prodrug target to increase oral drug absorption. In the absence of a high resolution hASBT crystal structure, 3D-QSAR modeling may prove beneficial in designing prodrug targets to hASBT. The objective was to derive a conformationally sampled pharmacophore 3D–QSAR (CSP-SAR) model for the uptake of bile acid conjugates by hASBT. A series of bile acid conjugates of glutamyl chenodeoxycholate were evaluated in terms of Km and normalized Vmax(normVmax) using hASBT-MDCK cells. All mono-anionic conjugates were potent substrates. Dianions, cations and zwitterions, which bound with a high affinity, were not substrates. CSP-SAR models were derived using structural and physicochemical descriptors, and evaluated via cross-validation. The best CSP-SAR model for Km included two structural and two physiochemical descriptors, where substrate hydrophobicity enhanced affinity. A best CSP-SAR model for Km/normVmax employed one structural and three physicochemical descriptors, also indicating hydrophobicity enhanced efficiency. Overall, the bile acid C-24 region accommodated a range of substituted anilines, provided a single negative charge was present near C-24. In comparing uptake findings to prior inhibition results, increased hydrophobicity enhanced activity, with dianions and zwitterions hindering activity. PMID:20939504

  2. Bile acids conjugation in human bile is not random: new insights from (1)H-NMR spectroscopy at 800 MHz.

    PubMed

    Nagana Gowda, G A; Shanaiah, Narasimhamurthy; Cooper, Amanda; Maluccio, Mary; Raftery, Daniel

    2009-06-01

    Bile acids constitute a group of structurally closely related molecules and represent the most abundant constituents of human bile. Investigations of bile acids have garnered increased interest owing to their recently discovered additional biological functions including their role as signaling molecules that govern glucose, fat and energy metabolism. Recent NMR methodological developments have enabled single-step analysis of several highly abundant and common glycine- and taurine- conjugated bile acids, such as glycocholic acid, glycodeoxycholic acid, glycochenodeoxycholic acid, taurocholic acid, taurodeoxycholic acid, and taurochenodeoxycholic acid. Investigation of these conjugated bile acids in human bile employing high field (800 MHz) (1)H-NMR spectroscopy reveals that the ratios between two glycine-conjugated bile acids and their taurine counterparts correlate positively (R2 = 0.83-0.97; p = 0.001 x 10(-2)-0.006 x 10(-7)) as do the ratios between a glycine-conjugated bile acid and its taurine counterpart (R2 = 0.92-0.95; p = 0.004 x 10(-3)-0.002 x 10(-10)). Using such correlations, concentration of individual bile acids in each sample could be predicted in good agreement with the experimentally determined values. These insights into the pattern of bile acid conjugation in human bile between glycine and taurine promise useful clues to the mechanism of bile acids' biosynthesis, conjugation and enterohepatic circulation, and may improve our understanding of the role of individual conjugated bile acids in health and disease. PMID:19373503

  3. Bile acid conjugation in early stage cholestatic liver disease before and during treatment with ursodeoxycholic acid.

    PubMed

    Fracchia, M; Setchell, K D; Crosignani, A; Podda, M; O'Connell, N; Ferraris, R; Hofmann, A F; Galatola, G

    1996-04-30

    The efficiency of bile acid conjugation before and during therapy with 600 mg/day of ursodeoxycholic acid was measured in seven adult patients with early chronic cholestatic liver disease (6 with primary biliary cirrhosis; 1 with primary sclerosing cholangitis). Duodenal bile samples were obtained by aspiration and the proportion of unconjugated bile acids was determined using lipophilic anion exchange chromatography to separate bile acid classes, followed by analysis of individual bile acids by gas chromatography-mass spectrometry. The proportion of conjugated bile acids was determined by high-performance liquid chromatography. Use of a (99m)Tc-HIDA recovery marker permitted the absolute mass of unconjugated bile acids in the gallbladder to be calculated. Unconjugated bile acids comprised 0.4% of total biliary bile acids before and 0.2% during ursodeoxycholic acid therapy, indicating highly efficient conjugation of bile acids. During therapy, percentage unconjugated ursodeoxycholic acid significantly increased from (mean +/- S.D.) 13 +/- 13% to 54 +/- 12%; P < 0.002. When the unconjugated and conjugated fractions of bile acids were compared, there was an enrichment in unconjugated fraction for cholic acid and ursodeoxycholic acid and a depletion for chenodeoxycholic acid both in basal condition and during ursodeoxycholic acid therapy, suggesting that hydrophilic bile acids were conjugated less efficiently. During therapy, the conjugation efficiency significantly increased for cholic acid and ursodeoxycholic acid. The pretreatment mass of total unconjugated bile acids in the gallbladder was (mean +/- S.D.) 4.4 +/- 3.2 mumol, and was not significantly changed by ursodeoxycholic acid therapy (6.2 +/- 3.5 mumol). However, ursodeoxycholic acid therapy caused a significant increase in the mass of unconjugated ursodeoxycholic acid. It is concluded that endogenous bile acids and exogenous ursodeoxycholic acid when given at the usual dose are efficiently conjugated in

  4. Increased acyclovir oral bioavailability via a bile acid conjugate.

    PubMed

    Tolle-Sander, Sanna; Lentz, Kimberley A; Maeda, Dean Y; Coop, Andrew; Polli, James E

    2004-01-12

    The objective of this work was to design an acyclovir prodrug that would utilize the human apical sodium-dependent bile acid transporter (hASBT) and enhance acyclovir oral bioavailability. Using each chenodeoxycholate, deoxycholate, cholate, and ursodeoxycholate, four bile acid prodrugs of acyclovir were synthesized, where acyclovir was conjugated to a bile acid via a valine linker. The affinity of the prodrug for hASBT was determined through inhibition of taurocholate uptake by COS-7 cells transfected with hASBT (hASBT-COS). The prodrug with the highest inhibitory affinity was further evaluated in vitro and in vivo. The prodrug acyclovir valylchenodeoxycholate yielded the highest affinity for hASBT (Ki = 35 microM), showing that chenodeoxycholate is the free bile acid with the greatest affinity for hASBT. Acyclovir valylchenodeoxycholate's affinity was similar to that of cholic acid (Ki = 25 microM). Further characterization showed that acyclovir was catalytically liberated from acyclovir valylchenode-oxycholate by esterase. Relative to cellular uptake studies of acyclovir alone, the cellular uptake from the prodrug resulted in a 16-fold greater acyclovir accumulation within hASBT-COS cells, indicating enhanced permeation properties of the prodrug. Enhanced permeability was due to hASBT-mediated uptake and increased passive permeability. The extent of acyclovir uptake in the presence of sodium was 1.4-fold greater than the extent of passive prodrug uptake in the absence of sodium (p = 0.02), indicating translocation of the prodrug by hASBT. The prodrug also exhibited an almost 12-fold enhanced passive permeability, relative to acyclovir's passive permeability. Oral administration of acyclovir valylchenodeoxycholate to rats resulted in a 2-fold increase in the bioavailability of acyclovir, compared to the bioavailability after administration of acyclovir alone. Results indicate that a bile acid prodrug strategy may be useful in improving the oral bioavailability of

  5. Synthesis of nucleoside and nucleotide conjugates of bile acids, and polymerase construction of bile acid-functionalized DNA.

    PubMed

    Ikonen, Satu; Macícková-Cahová, Hana; Pohl, Radek; Sanda, Miloslav; Hocek, Michal

    2010-03-01

    Aqueous Sonogashira cross-coupling reactions of 5-iodopyrimidine or 7-iodo-7-deazaadenine nucleosides with bile acid-derived terminal acetylenes linked via an ester or amide tether gave the corresponding bile acid-nucleoside conjugates. Analogous reactions of halogenated nucleoside triphosphates gave directly bile acid-modified dNTPs. Enzymatic incorporation of these modified nucleotides to DNA was successfully performed using Phusion polymerase for primer extension. One of the dNTPs (dCTP bearing cholic acid) was also efficient for PCR amplification. PMID:20165813

  6. Hepatic transport of bile acid and effect of conjugation.

    PubMed

    Kitani, K

    1995-06-01

    Biliary transport of bile salts was investigated by measuring: 1) biliary transport maxima values (Tm) for different conjugated bile salts; and 2) biliary excretion of unconjugated bile salts relative to their conjugates under the continuous i.v. infusion of various unconjugated bile salts. The order of Tm values found in the rat of both sexes was tauro (and glyco) ursodeoxycholate (TUDC, GUDC), tauro alpha- and beta-muricholate (T alpha-MC, T beta-MC) > taurocholate(TC) > taurochenodeoxycholate (TCDC), while in female hamsters it was TC > TCDC > TUDC. The differences in the Tm order between rats and hamsters cast doubt on the currently proposed view that the apparent Tm values of bile salts are primarily determined by their physical-chemical properties (detergent property in particular). The biliary excretion of unconjugated bile salts was most efficient with ursocholate (UC) and alpha-MC followed by beta-MC, with UDC (and probably 7 ketolithocholate) being the least efficient for excretion. Thus, while for some bile salts such as cholate and UC, the amidation is not a prerequisite to their efficient excretion, for other bile salts such as UDC, the amidation is an excellent mechanism for facilitating the biliary excretion. In an attempt to explain the above order for the efficacy of the biliary excretion of unconjugated bile salts on the basis of their physical-chemical properties, we must remember that unlike rats, the biliary excretion of dehydrocholate and cholate in dogs is more limited than their respective taurine conjugates.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8541581

  7. Gelation of self-assembed bile acid-PEG conjugates

    NASA Astrophysics Data System (ADS)

    Strandman, Satu; Le Devedec, Frantz; Zhu, X. X.

    2012-02-01

    The aggregation of macromolecules and low-molar-mass compounds into elongated self-assemblies such as wormlike micelles, fibers, or tubules increases the viscosity of the solutions and often leads to gelation due to network formation, even in organic solvents. Such one-dimensional nanostructures are promising candidates for drug delivery vehicles, packing materials for separation, templates for metal nanowires, biocides, and photo- or biocatalysis. An interesting group of compounds capable of this type of self-organization are bile acids, which are endogeneous steroids known to form gels at high concentrations and appropriate pH conditions. Grafting poly(ethylene oxide) on bile acids via anionic polymerization brings along thermoresponsiveness represented by lower critical solution temperature (LCST), while self-assembling occurs below another threshold temperature leading to a gelation at high concentrations, as shown by rheological experiments. The latter transition is assigned to the nanotube formation of pegylated bile acids, visualized by electron microscopy.

  8. N-acetylglucosaminides. A new type of bile acid conjugate in man.

    PubMed

    Marschall, H U; Egestad, B; Matern, H; Matern, S; Sjövall, J

    1989-08-01

    Bile acids were extracted from human urine and were separated into groups of nonamidated and glycine- and taurine-conjugated compounds. Each group was subfractionated in a reversed-phase high performance liquid chromatography system, and the fractions were analyzed by negative ion fast atom bombardment mass spectrometry and also by gas chromatography-mass spectrometry after enzymatic removal of glycine and taurine moieties. The major glycosides of the non-amidated bile acids were more polar than reference bile acid glucosides and gave quasimolecular ions at m/z 592, 594, and 610 consistent with N-acetylglucosaminides of unsaturated dihydroxy and saturated di- and trihydroxy bile acids. Gas chromatography-mass spectrometry analyses of methyl ester trimethylsilyl ether derivatives showed fragments typical for N-acetylglucosaminides (m/z 173 and 186) in addition to those also given by glucosides (m/z 204 and 217). The N-acetylglucosaminides were inert toward alpha- and beta-glucosidase but were cleaved completely with N-acetylglucosaminidase. The released sugar moiety was identified as N-acetylglucosamine. One of the liberated bile acids was identified as ursodeoxycholic acid. The other acids were not identical to any known primary or secondary bile acid in humans. Fast atom bombardment mass spectrometry analyses of the glycine-and taurine-conjugated bile acid glycosides only showed ions consistent with the presence of glucosides (m/z 626 and 676). These compounds were sensitive only toward beta-glucosidase which liberated a trihydroxy bile acid as the major compound. Based on the recover of 13C- and 14C-labeled chenodeoxycholic acid glucoside added as internal standard, the daily excretion of nonamidated bile acid glycosides was estimated to be about 137 micrograms or 0.29 mumol, N-acetylglucosaminides constituting about 90%. The daily excretion of the glucosides of amidated bile acids was about 150 micrograms or 0.25 mumol, glycine conjugates constituting about 90

  9. Molecular Switch Controlling the Binding of Anionic Bile Acid Conjugates to Human Apical Sodium-dependent Bile Acid Transporter

    PubMed Central

    Rais, Rana; Acharya, Chayan; Tririya, Gasirat; MacKerell, Alexander D.; Polli, James E.

    2010-01-01

    The human apical sodium-dependent bile acid transporter (hASBT) may serve as a prodrug target for oral drug absorption. Synthetic, biological, NMR and computational approaches identified the structure-activity relationships of mono- and dianionic bile acid conjugates for hASBT binding. Experimental data combined with a conformationally-sampled pharmacophore/QSAR modeling approach (CSP-SAR) predicted that dianionic substituents with intramolecular hydrogen bonding between hydroxyls on the cholane skeleton and the acid group on the conjugate's aromatic ring increased conjugate hydrophobicity and improved binding affinity. Notably, the model predicted the presence of a conformational molecular switch, where shifting the carboxylate substituent on an aromatic ring by a single position controlled binding affinity. Model validation was performed by effectively shifting the spatial location of the carboxylate by inserting a methylene adjacent to the aromatic ring, resulting in the predicted alteration in binding affinity. This work illustrates conformation as a determinant of ligand binding affinity to a biological transporter. PMID:20504026

  10. Disposition and metabolism of 2-fluoro-beta-alanine conjugates of bile acids following secretion into bile.

    PubMed

    Zhang, R W; Barnes, S; Diasio, R B

    1991-04-15

    Since 2-fluoro-beta-alanine (FBAL) conjugates of bile acids (BA), the primary biliary metabolites of fluoropyrimidine (FP) drugs, have been suggested to be related to the hepatotoxicity which develops in patients receiving FP chemotherapy by intrahepatic arterial infusion (Proc. Natl. Acad. Sci. USA 84, 5439-5443, 1987), it was important to determine whether they undergo enterohepatic circulation and hence accumulate in the liver and biliary system. In initial studies, sensitivity of FBAL-BA conjugates to hydrolysis by pancreatic enzymes was examined. In subsequent in vivo studies, a model FBAL-BA conjugate, FBAL-chenodeoxycholate (FBAL-CDC), was introduced into the lumen of the small intestine of anesthetized rats with biliary fistulas to quantitate the intestinal absorption, metabolism and tissue distribution of the conjugate. The results indicated that: (1) FBAL-BA conjugates were resistant to hydrolysis by pancreatic enzymes (carboxypeptidase A, carboxypeptidase B and trypsin) and by human pancreatic juice, but were completely hydrolyzed by cholyglycine hydrolase. (2) At least one-half of the administered FBAL-CDC was deconjugated during the process of intestinal absorption, as shown by HPLC analysis of the radioactivity in portal venous blood. (3) Deconjugated FBAL or CDC was reconjugated in liver with other bile acids or amino acids (glycine and taurine), respectively, as shown by radiochromatography of bile. (4) FBAL, formed as a result of hydrolysis of FBAL-CDC, had a wide tissue distribution. In conclusion, FBAL-CDC has a rapid turnover during its enterohepatic circulation due to deconjugation in the intestine and reconjugation in the liver. PMID:1902118

  11. Synthesis of conjugated bile acids/azastilbenes as potential antioxidant and photoprotective agents.

    PubMed

    dos Santos, Juliana Alves; Polonini, Hudson Caetano; Suzuki, Érika Yoko; Raposo, Nádia R B; da Silva, Adilson David

    2015-06-01

    A series of 14 bile acids/azastilbenes conjugates (1a-g and 2a-g) was prepared through the condensation of bile amides (1 and 2) and aromatic aldehydes. The newly synthesized conjugates were evaluated in vitro for their antioxidant and photoprotective activities. Six compounds (1, 1a, 1b, 2, 2a and 2b) showed promising antioxidant activity with IC50 values of 19.60-31.83 μg mL(-1). The synthesized compounds presented a varied photoprotection profile, with the SPF ranging from 2 to 9. Among the 16 compounds tested for the protection against UVB sunrays, 3 compounds (2c, 2e and 2g) presented more significant protection than resveratrol and the free azastilbene 3; while the UVAPF increased from 2 in resveratrol and 5 in 3 to 5-11 in the majority of the conjugates. PMID:25814069

  12. Effects of conjugated and unconjugated bile acids on the activity of the Vibrio cholerae porin OmpT.

    PubMed

    Pagel, Melissa; Delcour, Anne H

    2011-01-01

    During infection, the enteric pathogen Vibrio cholerae encounters a bile-containing environment. Previous studies have shown that bile and/or bile acids exert several effects on the virulence and physiology of the bacterial cells. These observations have led to the suggestion that bile acids may play a signaling role in infection. We have previously reported that the bile component deoxycholic acid blocks the general diffusion porin OmpT in a dose-dependent manner, presumably as it transits through the pore. V. cholerae colonizes the distal jejunum and ileum, where a mixture of various conjugated and unconjugated bile acids are found. In this work, we have used patch clamp electrophysiology to investigate the effects of six bile acids on OmpT. Two bile acids (deoxycholic and chenodeoxycholic acids) were found to block OmpT at physiological concentrations below 1 mM, while glycodeoxycholic acid was mildly effective and cholic, lithocholic and taurodeoxycholic acids were ineffective in this range. The block was also voltage-dependent. These observations suggest the presence of a specific binding site inside the OmpT pore. Since deconjugation is due to the activity of the endogenous flora, the preferential uptake of some unconjugated bile acids by OmpT may signal the presence of a hospitable environment. The results are also discussed in terms of the possible molecular interactions between the penetrating bile acid molecule and the channel wall. PMID:21067451

  13. Conjugated bile acids promote cholangiocarcinoma cell invasive growth through activation of sphingosine 1-phosphate receptor 2

    PubMed Central

    Liu, Runping; Zhao, Renping; Zhou, Xiqiao; Liang, Xiuyin; Campbell, Deanna JW; Zhang, Xiaoxuan; Zhang, Luyong; Shi, Ruihua; Wang, Guangji; Pandak, William M; Sirica, Alphonse E; Hylemon, Phillip B; Zhou, Huiping

    2014-01-01

    Cholangiocarcinoma (CCA) is an often fatal primary malignancy of the intra- and extrahepatic biliary tract that is commonly associated with chronic cholestasis and significantly elevated levels of primary and conjugated bile acids (CBAs), which are correlated with bile duct obstruction (BDO). BDO has also recently been shown to promote CCA progression. However, whereas there is increasing evidence linking chronic cholestasis and abnormal bile acid profiles to CCA development and progression, the specific mechanisms by which bile acids may be acting to promote cholangiocarcinogenesis and invasive biliary tumor growth have not been fully established. Recent studies have shown that CBAs, but not free bile acids, stimulate CCA cell growth, and that an imbalance in the ratio of free to CBAs may play an important role in the tumorigenesis of CCA. Also, CBAs are able to activate extracellular signal-regulated kinase (ERK)1/2- and phosphatidylinositol-3-kinase/protein kinase B (AKT)-signaling pathways through sphingosine 1-phosphate receptor 2 (S1PR2) in rodent hepatocytes. In the current study, we demonstrate S1PR2 to be highly expressed in rat and human CCA cells, as well as in human CCA tissues. We further show that CBAs activate the ERK1/2- and AKT-signaling pathways and significantly stimulate CCA cell growth and invasion in vitro. Taurocholate (TCA)-mediated CCA cell proliferation, migration, and invasion were significantly inhibited by JTE-013, a chemical antagonist of S1PR2, or by lentiviral short hairpin RNA silencing of S1PR2. In a novel organotypic rat CCA coculture model, TCA was further found to significantly increase the growth of CCA cell spheroidal/“duct-like” structures, which was blocked by treatment with JTE-013. Conclusion: Our collective data support the hypothesis that CBAs promote CCA cell-invasive growth through S1PR2. PMID:24700501

  14. Conjugated bile acids activate the sphingosine-1-phosphate receptor 2 in primary rodent hepatocytes.

    PubMed

    Studer, Elaine; Zhou, Xiqiao; Zhao, Renping; Wang, Yun; Takabe, Kazuaki; Nagahashi, Masayuki; Pandak, William M; Dent, Paul; Spiegel, Sarah; Shi, Ruihua; Xu, Weiren; Liu, Xuyuan; Bohdan, Pat; Zhang, Luyong; Zhou, Huiping; Hylemon, Phillip B

    2012-01-01

    Bile acids have been shown to be important regulatory molecules for cells in the liver and gastrointestinal tract. They can activate various cell signaling pathways including extracellular regulated kinase (ERK)1/2 and protein kinase B (AKT) as well as the G-protein-coupled receptor (GPCR) membrane-type bile acid receptor (TGR5/M-BAR). Activation of the ERK1/2 and AKT signaling pathways by conjugated bile acids has been reported to be sensitive to pertussis toxin (PTX) and dominant-negative Gα(i) in primary rodent hepatocytes. However, the GPCRs responsible for activation of these pathways have not been identified. Screening GPCRs in the lipid-activated phylogenetic family (expressed in HEK293 cells) identified sphingosine-1-phosphate receptor 2 (S1P(2) ) as being activated by taurocholate (TCA). TCA, taurodeoxycholic acid (TDCA), tauroursodeoxycholic acid (TUDCA), glycocholic acid (GCA), glycodeoxycholic acid (GDCA), and S1P-induced activation of ERK1/2 and AKT were significantly inhibited by JTE-013, a S1P(2) antagonist, in primary rat hepatocytes. JTE-013 significantly inhibited hepatic ERK1/2 and AKT activation as well as short heterodimeric partner (SHP) mRNA induction by TCA in the chronic bile fistula rat. Knockdown of the expression of S1P(2) by a recombinant lentivirus encoding S1P(2) shRNA markedly inhibited the activation of ERK1/2 and AKT by TCA and S1P in rat primary hepatocytes. Primary hepatocytes prepared from S1P(2) knock out (S1P(2) (-/-) ) mice were significantly blunted in the activation of the ERK1/2 and AKT pathways by TCA. Structural modeling of the S1P receptors indicated that only S1P(2) can accommodate TCA binding. In summary, all these data support the hypothesis that conjugated bile acids activate the ERK1/2 and AKT signaling pathways primarily through S1P(2) in primary rodent hepatocytes. PMID:21932398

  15. Thermodynamic and solution state NMR characterization of the binding of secondary and conjugated bile acids to STARD5.

    PubMed

    Létourneau, Danny; Lorin, Aurélien; Lefebvre, Andrée; Cabana, Jérôme; Lavigne, Pierre; LeHoux, Jean-Guy

    2013-11-01

    STARD5 is a member of the STARD4 sub-family of START domain containing proteins specialized in the non-vesicular transport of lipids and sterols. We recently reported that STARD5 binds primary bile acids. Herein, we report on the biophysical and structural characterization of the binding of secondary and conjugated bile acids by STARD5 at physiological concentrations. We found that the absence of the 7α-OH group and its epimerization increase the affinity of secondary bile acids for STARD5. According to NMR titration and molecular modeling, the affinity depends mainly on the number and positions of the steroid ring hydroxyl groups and to a lesser extent on the presence or type of bile acid side-chain conjugation. Primary and secondary bile acids have different binding modes and display different positioning within the STARD5 binding pocket. The relative STARD5 affinity for the different bile acids studied is: DCA>LCA>CDCA>GDCA>TDCA>CA>UDCA. TCA and GCA do not bind significantly to STARD5. The impact of the ligand chemical structure on the thermodynamics of binding is discussed. The discovery of these new ligands suggests that STARD5 is involved in the cellular response elicited by bile acids and offers many entry points to decipher its physiological role. PMID:23872533

  16. HPLC-fluorescence determination of individual free and conjugated bile acids in human serum.

    PubMed

    Gatti, R; Roda, A; Cerre, C; Bonazzi, D; Cavrini, V

    1997-01-01

    A method for the quantitative analysis of unconjugated and conjugated bile acids (BA) in serum of patients with primary biliary cirrhosis (PBC) before and after therapy with antibiotic or ursodeoxycholic acid (UDCA) is described. After separation of the free, glycine and taurine conjugated (F, G and T conjugated) fractions by solid-phase extraction, the isolated T conjugates were hydrolysed enzymatically using cholyglycine hydrolase. The BA fractions were derivatized using 2-bromoacetyl-6-methoxynaphthalene (Br-AMN) and detected fluorimetrically (lambda exc = 300 nm, lambda em = 460 nm). The derivatization reaction was performed under mild conditions (10 min at 40 degrees C) in an aqueous medium in the presence of tetrakis (decyl) ammonium bromide (TDeABr). The HPLC separation was achieved using an ODS column and with a mobile phase gradient mixture of A-B, where A is water and B is acetonitrile:methanol (60:40 v/v) for elution at a flow-rate of 1.2 mL/min. The reproducibility, recovery and separation of individual BA under gradient elution conditions were satisfactory, allowing a sensitive detection of each BA in serum samples with a detection limit of about 1-2 pmol. PMID:9051208

  17. Structure of conjugated bile salt-fatty acid-monoglyceride mixed colloids: Studies by small-angle neutron scattering

    SciTech Connect

    Hjelm, R.P.; Schteingart, C.D.; Hofmann, A.F.; Thiyagarajan, P.

    2000-01-20

    The structures of particles found in isotropic phases of mixed surfactant systems consisting of conjugated bile salts and fatty lipids were assessed using small-angle neutron scattering. The conjugated bile salts were either cholylglycine or chenodeoxycholylglycine. The fatty lipids were mixtures of oleate and oleic acid either alone or with monoolein. The scattering data suggested that both particle interactions and polydispersity must be modeled in these systems. Particle interactions were modeled using the reduced mean spherical approximation and the decoupling approximation. Maximum entropy was used to characterize the polydispersity. A self-consistent analysis of the scattering was arrived at by making an initial estimate of particle size and shape using derivative-log and Guinier analysis and refining the estimates by analyzing the particle interactions and polydispersity and iterating. There are sufficient similarities in the particle morphologies of these and other conjugated bile salt-fatty lipid systems to suggest a common mode of self-assembly. These solutions are models for bile in the bilary system and intestine content during triglyceride digestion; the common themes of self-assembly have implications for the physiology of lipid solubilization in bile as well as intestinal absorption of dietary lipids.

  18. Cytosol-nucleus traffic and colocalization with FXR of conjugated bile acids in rat hepatocytes.

    PubMed

    Monte, Maria J; Rosales, Ruben; Macias, Rocio I R; Iannota, Valeria; Martinez-Fernandez, Almudena; Romero, Marta R; Hofmann, Alan F; Marin, Jose J G

    2008-07-01

    Bile acids (BAs) are natural ligands of nuclear receptors, in particular farnesoid X receptor (FXR). Whether, in addition to protein-mediated cytosolic-nuclear BA translocation, other mechanisms are involved in the access of BAs to nuclear FXR was investigated. When rat hepatocytes were incubated with radiolabeled taurocholic acid, taurodeoxycholic acid, taurochenodeoxycholic acid, and tauroursodeoxycholic acid, their nuclear accumulation was proportional to their intracellular levels. With the use of flow cytometry analysis, the accumulation by nuclei isolated from rat liver cells was found to differ for several fluorescent compounds of similar molecular weight and different charge, including fluorescein-tagged BAs [cholylglycyl amidofluorescein (CGamF), ursodeoxycholylglycyl amidofluorescein, or chenodeoxycholylglycyl amidofluorescein]. When we varied nuclear volume by incubation with different sucrose concentrations, a similar relationship between nuclear volume and content of FITC and 4-kDa FITC-dextran was found. In contrast, this relationship was markedly lower for CGamF. Confocal microscopy studies revealed that fluorescein-tagged BAs, but also FITC or 10-kDa FITC-dextran were found in the nuclear envelope and concentrated in regions where DNA was less densely packed. In contrast to the cytosolic subcellular localization of peroxisome proliferator-activated receptor-alpha, FXR and nucleolin (a marker of transcriptional active chromatin) were also localized by immunoreactivity in these intranuclear regions. In conclusion, although intranuclear levels of small organic molecules including conjugated BAs depend on their concentrations in the extranuclear space, the existence of certain molecular selectivity (not strictly dependent on molecular weight or charge) suggests that, in addition to simple diffusional exchange, other mechanisms may be also involved in determining their overall nuclear content in regions where these compounds coincide and may interact

  19. Comparative analysis of conjugated bile acids in human serum using high-performance liquid chromatography and capillary electrophoresis.

    PubMed

    Lee, B L; New, A L; Ong, C N

    1997-12-19

    This paper describes the analysis of conjugated bile acids in human serum using reversed-phase high-performance liquid chromatography (HPLC) and micellar electrokinetic capillary electrophoresis (CE). Samples of healthy subjects and patients with different hepatic diseases were pretreated with a simple preparation procedure using a solid-phase extraction technique. The optimal analytical conditions of both chromatographic methods were investigated for the convenience and reliability for routine analysis. Both HPLC and CE methods were found to be reliable and compatible. The recoveries of nine bile acid conjugates using both methods were generally >85% and reproducibility >90%. The day-to-day variation of retention time was <5% for HPLC, while the variation of migration time for CE was <3%. Although the detection limit of the HPLC method (1 nmol/ml) was five times more sensitive than that of the CE method, the CE method was considered to be more time and cost effective. PMID:9518169

  20. Toxicity and intracellular accumulation of bile acids in sandwich-cultured rat hepatocytes: role of glycine conjugates.

    PubMed

    Chatterjee, Sagnik; Bijsmans, Ingrid T G W; van Mil, Saskia W C; Augustijns, Patrick; Annaert, Pieter

    2014-03-01

    Excessive intrahepatic accumulation of bile acids (BAs) is a key mechanism underlying cholestasis. The aim of this study was to quantitatively explore the relationship between cytotoxicity of BAs and their intracellular accumulation in sandwich-cultured rat hepatocytes (SCRH). Following exposure of SCRH (on day-1 after seeding) to various BAs for 24h, glycine-conjugated BAs were most potent in exerting toxicity. Moreover, unconjugated BAs showed significantly higher toxicity in day-1 compared to day-3 SCRH. When day-1/-3 SCRH were exposed (0.5-4h) to 5-100μM (C)DCA, intracellular levels of unconjugated (C)DCA were similar, while intracellular levels of glycine conjugates were up to 4-fold lower in day-3 compared to day-1 SCRH. Sinusoidal efflux was by far the predominant efflux pathway of conjugated BAs both in day-1 and day-3 SCRH, while canalicular BA efflux showed substantial interbatch variability. After 4h exposure to (C)DCA, intracellular glycine conjugate levels were at least 10-fold higher than taurine conjugate levels. Taken together, reduced BA conjugate formation in day-3 SCRH results in lower intracellular glycine conjugate concentrations, explaining decreased toxicity of (C)DCA in day-3 versus day-1 SCRH. Our data provide for the first time a direct link between BA toxicity and glycine conjugate exposure in SCRH. PMID:24211540

  1. L-arginine conjugates of bile acids-a possible treatment for non-alcoholic fatty liver disease

    PubMed Central

    2014-01-01

    Background Non-alcoholic fatty liver disease (NAFLD) is a continuum of diseases that include simple steatosis and non-alcoholic steatohepatitis (NASH) ultimately leading to cirrhosis, hepatocellular carcinoma and end stage liver failure. Currently there is no approved treatment for NASH. It is known that bile acids not only have physiological roles in lipid digestion but also have strong hormonal properties. We have synthesized a novel chenodeoxycholyl-arginine ethyl ester conjugate (CDCArg) for the treatment of NAFLD. Methods Chemical synthesis of CDCArg was performed. Experiments for prevention and treatment of NAFLD were carried out on C57BL/6 J male mice that were treated with high fat diet (HFD, 60% calories from fat). CDCArg or cholic acid bile acids were admixture into the diets. Food consumption, weight gain, liver histology, intraperitoneal glucose tolerance test, biochemical analysis and blood parameters were assessed at the end of the experiment after 5 weeks of diet (prevention study) or after 14 weeks of diet (treatment study). In the treatment study CDCArg was admixture into the diet at weeks 10–14. Results In comparison to HFD treated mice, mice treated with HFD supplemented with CDCArg, showed reduced liver steatosis, reduced body weight and decreased testicular fat and liver tissue mass. Blood glucose, cholesterol, insulin and leptin levels were also lower in this group. No evidence of toxicity of CDCArg was recorded. In fact, liver injury, as evaluated using plasma hepatic enzyme levels, was low in mice treated with HFD and CDCArg when compared to mice treated with HFD and cholic acid. Conclusion CDCArg supplementation protected the liver against HFD-induced NAFLD without any toxic effects. These results indicate that basic amino acids e.g., L-arginine and bile acids conjugates may be a potential therapy for NAFLD. PMID:24750587

  2. Comparative abilities and optimal conditions for beta-glycosidase enzymes to hydrolyse the glucuronide, glucoside, and N-acetylglucosaminide conjugates of bile acids.

    PubMed

    Momose, T; Maruyama, J; Iida, T; Goto, J; Nambara, T

    1997-08-01

    Enzymatic hydrolyses were described for three variants of glycosidic conjugated bile acids with one beta-glucuronidase (Helix pomatia), three beta-glucosidase (almonds, sweet almonds, and Escherichia coli), and four beta-N-acetylglucosaminidase (jack beans, bovine kidney, human placenta, and Diplococcus pneumoniae) preparations. The substrates include the beta-glucuronide, beta-glucoside, and beta-N-acetylglucosaminide conjugates of bile acids related to hyodeoxycholic, murideoxycholic, chenodeoxycholic, and ursodeoxycholic acids possessing a sugar moiety at position C-3, C-6 or C-7. The comparative abilities and optimal conditions for the beta-glycosidases to catalyze the hydrolyses of the substrates were clarified by changing pHs and incubation times. Hydrolysis rates of the bile acid glycosides with beta-glycosidase treatments were influenced by both the source of the enzyme preparations and the conjugated position of a sugar moiety in the substrates, and the 3-glucoside and 3-N-acetylglucosaminide conjugates were usually hydrolyzed more efficiently than their corresponding 6- and 7-analogs. Escherichia coli and jack bean enzymes were chosen to hydrolyse the glucosidic and N-acetylglucosaminidic conjugated bile acids, respectively. PMID:9300125

  3. Rapid quantification of conjugated and unconjugated bile acids and C27 precursors in dried blood spots and small volumes of serum.

    PubMed

    Janzen, N; Sander, S; Terhardt, M; Das, A M; Sass, J O; Kraetzner, R; Rosewich, H; Rosevich, H; Peter, M; Sander, J

    2010-06-01

    The aim of the study was to develop a method for fast and reliable diagnosis of peroxisomal diseases and to facilitate differential diagnosis of cholestatic hepatopathy. For the quantification of bile acids and their conjugates as well as C(27) precursors di- and trihydroxycholestanoic acid (DHCA, THCA), in small pediatric blood samples we combined HPLC separation on a reverse-phase C18 column with ESI-MS/MS analysis in the negative ion mode. Analysis was done with good precision (CV 3,7%-11.1%) and sufficient sensitivity (LOQ: 11-91 nmol/L) without derivatization. Complete analysis of 17 free and conjugated bile acids from dried blood spots and 10 microL serum samples, respectively, was performed within 12 min. Measurement of conjugated primary bile acids plus DHCA and THCA as well as ursodeoxycholic acid was done in 4.5 min. In blood spots of healthy newborns, conjugated primary bile acids were found in the range of 0.01 to 2.01 micromol/L. Concentrations of C(27) precursors were below the detection limit in normal controls. DHCA and THCA were specifically elevated in cases of peroxysomal defects and one Zellweger patient. PMID:20093478

  4. Bile acid transporters

    PubMed Central

    Dawson, Paul A.; Lan, Tian; Rao, Anuradha

    2009-01-01

    In liver and intestine, transporters play a critical role in maintaining the enterohepatic circulation and bile acid homeostasis. Over the past two decades, there has been significant progress toward identifying the individual membrane transporters and unraveling their complex regulation. In the liver, bile acids are efficiently transported across the sinusoidal membrane by the Na+ taurocholate cotransporting polypeptide with assistance by members of the organic anion transporting polypeptide family. The bile acids are then secreted in an ATP-dependent fashion across the canalicular membrane by the bile salt export pump. Following their movement with bile into the lumen of the small intestine, bile acids are almost quantitatively reclaimed in the ileum by the apical sodium-dependent bile acid transporter. The bile acids are shuttled across the enterocyte to the basolateral membrane and effluxed into the portal circulation by the recently indentified heteromeric organic solute transporter, OSTα-OSTβ. In addition to the hepatocyte and enterocyte, subgroups of these bile acid transporters are expressed by the biliary, renal, and colonic epithelium where they contribute to maintaining bile acid homeostasis and play important cytoprotective roles. This article will review our current understanding of the physiological role and regulation of these important carriers. PMID:19498215

  5. Fecal free and conjugated bile acids and neutral sterols in vegetarians, omnivores, and patients with colorectal cancer.

    PubMed

    Korpela, J T; Adlercreutz, H; Turunen, M J

    1988-04-01

    Increased excretion and intestinal bacterial metabolism of bile acids and neutral sterols have been suggested to be associated with an increased risk of colorectal cancer. We determined fecal neutral sterol and bile acid profiles by new capillary column gas-liquid chromatographic methods in 18 patients with colorectal cancer, 10 omnivores, and 10 vegetarians. The methods also determine concentrations of esterified neutral sterols and saponifiable bile acids formed by intestinal bacterial action. Patients with colorectal cancer had the highest concentrations of neutral animal sterols, the lowest degree of esterification of neutral sterols, the lowest relative amount of saponifiable bile acids, and the highest concentrations of unconjugated primary bile acids. These differences were statistically significant (p less than 0.05) and more profound when the patients were compared with vegetarians than with omnivores. Since epidemiologic studies suggest that vegetarians have a lower risk of colorectal cancer than omnivores, these differences are discussed as possible risk factors for colorectal cancer. PMID:3387891

  6. MSC-based VEGF gene therapy in rat myocardial infarction model using facial amphipathic bile acid-conjugated polyethyleneimine.

    PubMed

    Moon, Hyung-Ho; Joo, Min Kyung; Mok, Hyejung; Lee, Minhyung; Hwang, Ki-Chul; Kim, Sung Wan; Jeong, Ji Hoon; Choi, Donghoon; Kim, Sun Hwa

    2014-02-01

    Mesenchymal stem cells (MSCs) have attracted much attention in regenerative medicine owing to their apparent usefulness as multi-potent replacement cells. The potential of MSC therapy can be further improved by transforming MSCs with therapeutic genes that maximize the efficacy of gene therapy and their own therapeutic ability. Since most conventional transfection methodologies have shown marginal success in delivering exogenous genes into primary cultured cells, efficient gene transfer into primary MSCs is a prerequisite for the development of MSC-based gene therapy strategies to achieve repair and regeneration of damaged tissues. Herein, facially amphipathic bile acid-modified polyethyleneimine (BA-PEI) conjugates were synthesized and used to transfer hypoxia-inducible vascular endothelial growth factor gene (pHI-VEGF) in MSCs for the treatment of rat myocardial infarction. Under the optimized transfection conditions, the BA-PEI conjugates significantly increased the VEGF protein expression levels in rat MSCs, compared with traditional transfection methods such as Lipofectamine™ and branched-PEI (25 kDa). Furthermore, the prepared pHI-VEGF-engineered MSCs (VEGF-MSCs) resulted in improved cell viability, particularly during severe hypoxic exposure in vitro. The transplantation of MSCs genetically modified to overexpress VEGF by BA-PEI enhanced the capillary formation in the infarction region and eventually attenuated left ventricular remodeling after myocardial infarction in rats. This study demonstrates the applicability of the BA-PEI conjugates for the efficient transfection of therapeutic genes into MSCs and the feasibility of using the genetically engineered MSCs in regenerative medicine for myocardial infarction. PMID:24280192

  7. Effect of cholestyramine on bile acid metabolism in normal man

    PubMed Central

    Garbutt, J. T.; Kenney, T. J.

    1972-01-01

    The effect of cholestyramine administration on the enterohepatic circulation of bile acids was studied in eight normal volunteers. In six subjects the metabolism of sodium taurocholate-14C was determined after its intravenous injection before and during the 6th wk of cholestyramine administration, 16 g/day. In two subjects, the metabolism of cholic acid-14C was observed before and during the 2nd wk of cholestyramine, 16 g/day. Bile acid sequestration resulted in a more rapid disappearance of the injected primary bile acid and its metabolic products. The composition of fasting bile acids was promptly altered by cholestyramine to predominantly glycine-conjugated trihydroxy bile acid. In four subjects, unconjugated bile acid-14C was administered during cholestyramine administration; the relative proportion of glycine-conjugated bile acid-14C before enterohepatic circulation was similar to the relative proportion of unlabeled glycine-conjugated bile acid present in duodenal contents after an overnight fast, indicating that a hepatic mechanism was responsible for the elevated ratios of glycine- to taurine-conjugated bile acid (G: T ratios) observed. The relative proportions of both dihydroxy bile acids, chenodeoxycholic and deoxycholic, were significantly reduced. Steatorrhea did not occur, and the total bile acid pool size determined after an overnight fast was unaltered by cholestyramine. These findings suggest that in normal man bile acid sequestered from the enterohepatic circulation by cholestyramine is replaced by an increase in hepatic synthesis primarily via the pathway leading to production of glycocholic acid. PMID:5080408

  8. Evaluation of ileal function using 23-selena-25-homotaurocholate, a-gamma-labeled conjugated bile acid. Initial clinical assessment

    SciTech Connect

    Nyhlin, H.; Merrick, M.V.; Eastwood, M.A.; Brydon, W.G.

    1983-01-01

    23-Selena-25-homotaurocholate is a synthetic bile acid labeled with a gamma-ray-emitting radioisotope /sup 75/Se. It is readily measured using external detectors and is thus suitable for whole-body counting. Whole-body retention was measured at 0, 4, and 7 days after oral administration to normal controls and to patients with disease of the small intestine, colon, or ileocecal region. Whole-body retention of less than 25% of the administered radioactivity within 4 days is definitely abnormal, but there was overlap between normal and abnormal groups at this time. At 7 days, whole-body retention less than 12% is abnormal and greater than 19% is normal. Between these limits, values may represent minimal ileal dysfunction not demonstrable by older techniques. Excretion of 23-selena-25-homotaurocholate follows a biexponential curve. The faster component has a half-life similar to that of natural bile acid. It is uncertain whether the slower component represents a hitherto unrecognized slowly turning over pool of bile acid or is a metabolic product of 23-selena-25-homotaurocholate not yet identified in vitro. There is a significant relationship between the whole-body retention of 23-selena-25-homotaurocholate and total fecal and primary bile acids. 23-selena-25-homotaurocholate is simple and acceptable for investigating ileal function.

  9. Upregulation of UGT2B4 Expression by 3'-Phosphoadenosine-5'-Phosphosulfate Synthase Knockdown: Implications for Coordinated Control of Bile Acid Conjugation.

    PubMed

    Barrett, Kathleen G; Fang, Hailin; Cukovic, Daniela; Dombkowski, Alan A; Kocarek, Thomas A; Runge-Morris, Melissa

    2015-07-01

    During cholestasis, the bile acid-conjugating enzymes, SULT2A1 and UGT2B4, work in concert to prevent the accumulation of toxic bile acids. To understand the impact of sulfotransferase deficiency on human hepatic gene expression, we knocked down 3'-phosphoadenosine-5'-phosphosulfate synthases (PAPSS) 1 and 2, which catalyze synthesis of the obligate sulfotransferase cofactor, in HepG2 cells. PAPSS knockdown caused no change in SULT2A1 expression; however, UGT2B4 expression increased markedly (∼41-fold increase in UGT2B4 mRNA content). Knockdown of SULT2A1 in HepG2 cells also increased UGT2B4 expression. To investigate the underlying mechanism, we transfected PAPSS-deficient HepG2 cells with a luciferase reporter plasmid containing ∼2 Kb of the UGT2B4 5'-flanking region, which included a response element for the bile acid-sensing nuclear receptor, farnesoid X receptor (FXR). FXR activation or overexpression increased UGT2B4 promoter activity; however, knocking down FXR or mutating or deleting the FXR response element did not significantly decrease UGT2B4 promoter activity. Further evaluation of the UGT2B4 5'-flanking region indicated the presence of distal regulatory elements between nucleotides -10090 and -10037 that negatively and positively regulated UGT2B4 transcription. Pulse-chase analysis showed that increased UGT2B4 expression in PAPSS-deficient cells was attributable to both increased mRNA synthesis and stability. Transfection analysis demonstrated that the UGT2B4 3'-untranslated region decreased luciferase reporter expression less in PAPSS-deficient cells than in control cells. These data indicate that knocking down PAPSS increases UGT2B4 transcription and mRNA stability as a compensatory response to the loss of SULT2A1 activity, presumably to maintain bile acid-conjugating activity. PMID:25948711

  10. Bile acid sequestrants for cholesterol

    MedlinePlus

    Bile acid sequestrants are medicines that help lower your LDL (bad) cholesterol . Too much cholesterol in your blood can ... block them. These medicines work by blocking bile acid in your stomach from being absorbed in your ...

  11. The mechanism of diarrhoea resulting from pelvic and abdominal radiotherapy; a prospective study using selenium-75 labelled conjugated bile acid and cobalt-58 labelled cyanocobalamin.

    PubMed

    Yeoh, E K; Lui, D; Lee, N Y

    1984-12-01

    An attempt was made to elucidate the mechanism of diarrhoea resulting from pelvic and abdominal radiotherapy in a prospective study of 10 patients undergoing treatment for curable pelvic malignant tumours using the synthetic trihydroxy 75Se-labelled conjugated bile acid, SeHcat and 58Co-labelled cyanocobalamin (58Co Vit B12). Evidence of malabsorption of vitamin B12 measured as a significant fall in whole body percentage retention of 58Co Vit B12 from baseline levels was found in all nine patients who developed diarrhoea during radiotherapy. Only four out of these nine patients also had malabsorption of the trihydroxy conjugated bile acid, cholic acid, measured as a significant fall in SeHcat whole body percentage retention and these patients had the most severe diarrhoea. The findings are discussed in the light of what is known about the pathophysiology of diarrhoea during pelvic and abdominal radiotherapy and lend support to previous work which implicated increased bowel motility in the pathogenesis of radiation-induced diarrhoea. The hypothesis that local neuroendocrine mechanisms in the gut may be involved is put forward, with possible implications for treatment. PMID:6509291

  12. Bilirubin conjugates of human bile. The excretion of bilirubin as the acyl glycosides of aldobiouronic acid, pseudoaldobiouronic acid and hexuronosylhexuronic acid, with a branched-chain hexuronic acid as one of the components of hexuronosylhexuronide

    PubMed Central

    Kuenzle, Clive C.

    1970-01-01

    Structure elucidations have been performed on the bilirubin conjugates isolated from human hepatic bile as the phenylazo derivatives. The major bilirubin conjugates are excreted, not as was formerly thought in the form of glucuronides, but as the acyl glycosides of aldobiouronic acid, pseudoaldobiouronic acid and hexuronosylhexuronic acid. The isolated aldobiouronides are proposed to have the structures of an acyl 6-O-hexopyranosyluronic acid-hexopyranoside, an acyl 4-O-hexofuranosyluronic acid-d-glucopyranoside, and an acyl 4-O-β-d-glucofuranosyluronic acid-d-glucopyranoside respectively, with the acyl radicals being those of the phenylazo derivative of bilirubin. The pseudoaldobiouronide is suggested to be the acyl 4-O-α-d-glucofuranosyl-β-d -glucopyranosiduronic acid, with the acyl radical being that of the phenylazo derivative of vinylneoxanthobilirubinic acid. The hexuronosylhexuronide presumably is the acyl 4-O-(3-C-hydroxymethylribofuranosyluronic acid)-β-d-glucopyranosiduronic acid, with the acyl radical being that of the phenylazo derivative of bilirubin. The 3-C-hydroxymethylriburonic acid, isolated as one of the components of the hexuronosylhexuronide, is the first natural branched-chain hexuronic acid to be detected, and the first branched-chain sugar ever detected in humans. PMID:5500303

  13. 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

  14. 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

  15. Distribution of free and conjugated cannabinoids in human bile samples.

    PubMed

    Fabritius, Marie; Staub, Christian; Mangin, Patrice; Giroud, Christian

    2012-11-30

    The metabolism of Δ(9)-tetrahydrocannabinol (THC) is relatively complex, and over 80 metabolites have been identified. However, much less is known about the formation and fate of cannabinoid conjugates. Bile excretion is known to be an important route for the elimination of phase II metabolites. A liquid chromatography-tandem mass spectrometry LC-MS/MS procedure for measuring cannabinoids in oral fluid was adapted, validated and applied to 10 bile samples. THC, 11-hydroxy-Δ(9)-tetrahydrocannabinol (11-OH-THC), 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THCCOOH), cannabinol (CBN), cannabidiol (CBD), Δ(9)-tetrahydrocannabinolic acid A (THC-A), 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol glucuronide (THCCOOH-gluc) and Δ(9)-tetrahydrocannabinol glucuronide (THC-gluc) were determined following solid-phase extraction and LC-MS/MS. High concentrations of THCCOOH-gluc were found in bile samples (range: 139-21,275 ng/mL). Relatively high levels of THCCOOH (7.7-1548 ng/mL) and THC-gluc (38-1366 ng/mL) were also measured. THC-A, the plant precursor of THC, was the only cannabinoid that was not detected. These results show that biliary excretion is an important route of elimination for cannabinoids conjugates and that their enterohepatic recirculation is a significant factor to consider when analyzing blood elimination profiles of cannabinoids. Furthermore, we suggest that the bile is the matrix of choice for the screening of phase II cannabinoid metabolites. PMID:22980143

  16. Upregulation of UGT2B4 Expression by 3′-Phosphoadenosine-5′-Phosphosulfate Synthase Knockdown: Implications for Coordinated Control of Bile Acid Conjugation

    PubMed Central

    Barrett, Kathleen G.; Fang, Hailin; Cukovic, Daniela; Dombkowski, Alan A.; Kocarek, Thomas A.

    2015-01-01

    During cholestasis, the bile acid–conjugating enzymes, SULT2A1 and UGT2B4, work in concert to prevent the accumulation of toxic bile acids. To understand the impact of sulfotransferase deficiency on human hepatic gene expression, we knocked down 3′-phosphoadenosine-5′-phosphosulfate synthases (PAPSS) 1 and 2, which catalyze synthesis of the obligate sulfotransferase cofactor, in HepG2 cells. PAPSS knockdown caused no change in SULT2A1 expression; however, UGT2B4 expression increased markedly (∼41-fold increase in UGT2B4 mRNA content). Knockdown of SULT2A1 in HepG2 cells also increased UGT2B4 expression. To investigate the underlying mechanism, we transfected PAPSS-deficient HepG2 cells with a luciferase reporter plasmid containing ∼2 Kb of the UGT2B4 5′-flanking region, which included a response element for the bile acid–sensing nuclear receptor, farnesoid X receptor (FXR). FXR activation or overexpression increased UGT2B4 promoter activity; however, knocking down FXR or mutating or deleting the FXR response element did not significantly decrease UGT2B4 promoter activity. Further evaluation of the UGT2B4 5′-flanking region indicated the presence of distal regulatory elements between nucleotides −10090 and −10037 that negatively and positively regulated UGT2B4 transcription. Pulse-chase analysis showed that increased UGT2B4 expression in PAPSS-deficient cells was attributable to both increased mRNA synthesis and stability. Transfection analysis demonstrated that the UGT2B4 3′-untranslated region decreased luciferase reporter expression less in PAPSS-deficient cells than in control cells. These data indicate that knocking down PAPSS increases UGT2B4 transcription and mRNA stability as a compensatory response to the loss of SULT2A1 activity, presumably to maintain bile acid–conjugating activity. PMID:25948711

  17. Analysis of duodenal bile acids by high performance liquid chromatography in infants with cholestasis.

    PubMed

    Hsu, H Y; Tang, S Y; Chang, M H

    1991-05-01

    Non-sulfated bile acid levels including cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA), ursodeoxycholic acid (UDCA), five taurine conjugates, and five glycine conjugates in duodenal juice were measured in 50 Chinese infants with cholestasis to test their diagnostic value. All 17 with biliary atresia (BA) cases, 11 out of 26 neonatal hepatitis (NH) cases and one case with paucity of the interlobular bile duct were without detectable bile acids. In those NH patients with detectable bile acids, the major components were conjugated forms of CA and CDCA, which was similar to all 6 cases of the comparison group with other diseases. The minor bile acid components identified in them were glycine conjugated UDCA, free CDCA, free CA, and free and conjugated DCA. Only one patient with NH had taurine conjugated LCA. The mean total duodenal bile acid level in 15 patients with NH was significantly lower than that in the 6 patients of the comparison group. Most patients with NH had a CDCA/CA ratio of less than one, indicating that cholic acid is the predominant form in their bile. Glycine conjugated bile acids were the predominant bile acids present in 11 out of 15 patients with NH and 4 out of 6 of the comparison group patients. The results suggest that the detection of duodenal bile acids by a sensitive HPLC method is of limited value in making a differential diagnosis between BA and NH.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1680988

  18. Bile acids are nutrient signaling hormones.

    PubMed

    Zhou, Huiping; Hylemon, Phillip B

    2014-08-01

    Bile salts play crucial roles in allowing the gastrointestinal system to digest, transport and metabolize nutrients. They function as nutrient signaling hormones by activating specific nuclear receptors (FXR, PXR, Vitamin D) and G-protein coupled receptors [TGR5, sphingosine-1 phosphate receptor 2 (S1PR2), muscarinic receptors]. Bile acids and insulin appear to collaborate in regulating the metabolism of nutrients in the liver. They both activate the AKT and ERK1/2 signaling pathways. Bile acid induction of the FXR-α target gene, small heterodimer partner (SHP), is highly dependent on the activation PKCζ, a branch of the insulin signaling pathway. SHP is an important regulator of glucose and lipid metabolism in the liver. One might hypothesize that chronic low grade inflammation which is associated with insulin resistance, may inhibit bile acid signaling and disrupt lipid metabolism. The disruption of these signaling pathways may increase the risk of fatty liver and non-alcoholic fatty liver disease (NAFLD). Finally, conjugated bile acids appear to promote cholangiocarcinoma growth via the activation of S1PR2. PMID:24819989

  19. Impaired uptake of conjugated bile acids and hepatitis b virus pres1-binding in na+-taurocholate cotransporting polypeptide knockout mice

    PubMed Central

    Slijepcevic, Davor; Kaufman, Christina; Wichers, Catharina GK; Gilglioni, Eduardo H; Lempp, Florian A; Duijst, Suzanne; de Waart, Dirk R; Oude Elferink, Ronald PJ; Mier, Walter; Stieger, Bruno; Beuers, Ulrich; Urban, Stephan; van de Graaf, Stan FJ

    2015-01-01

    The Na+-taurocholate cotransporting polypeptide (NTCP) mediates uptake of conjugated bile acids (BAs) and is localized at the basolateral membrane of hepatocytes. It has recently been recognized as the receptor mediating hepatocyte-specific entry of hepatitis B virus and hepatitis delta virus. Myrcludex B, a peptide inhibitor of hepatitis B virus entry, is assumed to specifically target NTCP. Here, we investigated BA transport and Myrcludex B binding in the first Slc10a1-knockout mouse model (Slc10a1 encodes NTCP). Primary Slc10a1−/− hepatocytes showed absence of sodium-dependent taurocholic acid uptake, whereas sodium-independent taurocholic acid uptake was unchanged. In vivo, this was manifested as a decreased serum BA clearance in all knockout mice. In a subset of mice, NTCP deficiency resulted in markedly elevated total serum BA concentrations, mainly composed of conjugated BAs. The hypercholanemic phenotype was rapidly triggered by a diet supplemented with ursodeoxycholic acid. Biliary BA output remained intact, while fecal BA excretion was reduced in hypercholanemic Slc10a1−/− mice, explained by increased Asbt and Ostα/β expression. These mice further showed reduced Asbt expression in the kidney and increased renal BA excretion. Hepatic uptake of conjugated BAs was potentially affected by down-regulation of OATP1A1 and up-regulation of OATP1A4. Furthermore, sodium-dependent taurocholic acid uptake was inhibited by Myrcludex B in wild-type hepatocytes, while Slc10a1−/− hepatocytes were insensitive to Myrcludex B. Finally, positron emission tomography showed a complete abrogation of hepatic binding of labeled Myrcludex B in Slc10a1-/- mice. Conclusion: The Slc10a1-knockout mouse model supports the central role of NTCP in hepatic uptake of conjugated BAs and hepatitis B virus preS1/Myrcludex B binding in vivo; the NTCP-independent hepatic BA uptake machinery maintains a (slower) enterohepatic circulation of BAs, although it is occasionally

  20. Biliary bile acids in birds of the Cotingidae family: taurine-conjugated (24R,25R)-3α,7α,24-trihydroxy-5β-cholestan-27-oic acid and two epimers (25R and 25S) of 3α,7α-dihydroxy-5β-cholestan-27-oic acid.

    PubMed

    Hagey, Lee R; Iida, Takashi; Ogawa, Shoujiro; Adachi, Yuuki; Une, Mizuho; Mushiake, Kumiko; Maekawa, Masamitsu; Shimada, Miki; Mano, Nariyasu; Hofmann, Alan F

    2011-01-01

    Three C(27) bile acids were found to be major biliary bile acids in the capuchinbird (Perissocephalus tricolor) and bare-throated bellbird (Procnias nudicollis), both members of the Cotingidae family of the order Passeriformes. The individual bile acids were isolated by preparative RP-HPLC, and their structures were established by RP-HPLC, LC/ESI-MS/MS and NMR as well as by a comparison of their chromatographic properties with those of authentic reference standards of their 12α-hydroxy derivatives. The most abundant bile acid present in the capuchinbird bile was the taurine conjugate of C(27) (24R,25R)-3α,7α,24-trihydroxy-5β-cholestan-27-oic acid, a diastereomer not previously identified as a natural bile acid. The four diastereomers of taurine-conjugated (24ξ,25ξ)-3α,7α,24-trihydroxy-5β-cholestan-27-oic acid could be distinguished by NMR and were resolved by RP-HPLC. The RRT of the diastereomers (with taurocholic acid as 1.0) were found to be increased in the following order: (24R,25R)<(24S,25R)<(24S,25S)<(24R,25S). Two epimers (25R and 25S) of C(27) 3α,7α-dihydroxy-5β-cholestan-27-oic acid were also present (as the taurine conjugates) in both bird species. Epimers of the two compounds could be distinguished by their NMR spectra and resolved by RP-HPLC with the (25S)-epimer eluting before the (25R)-epimer. Characterization of the taurine-conjugated (24R,25R)-3α,7α,24-trihydroxy-5β-cholestan-27-oic acid and two epimers (25R and 25S) of 3α,7α-dihydroxy-5β-cholestan-27-oic acid should facilitate their detection in peroxisomal disease and inborn errors of bile acid biosynthesis. PMID:21600907

  1. 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 ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  3. Bile acids as metabolic regulators

    PubMed Central

    Li, Tiangang; Chiang, John Y. L.

    2015-01-01

    Summary Small molecule ligands that target to TGR5 and FXR have shown promise in treating various metabolic and inflammation-related human diseases. New insights into the mechanisms underlying the bariatric surgery and bile acid sequestrant treatment suggest that targeting the enterohepatic circulation to modulate gut-liver bile acid signaling, incretin production and microbiota represents a new strategy to treat obesity and type-2 diabetes. PMID:25584736

  4. Effect of ursodeoxycholic acid administration on bile acid composition in hamster bile.

    PubMed

    Matejka, M; Vescina, C; Carducci, C N; Alayón, A; Dios, A; Scarlatto, E; Mamianetti, A

    1990-01-01

    The modification in the composition of bile acids in hamster by the administration of high dose of ursodeoxycholic acid (UDCA) was investigated. Male Golden Syrian hamsters were divided into five groups: a control group, two groups that received 0.5 g of UDCA per 100 g of standard diet during 30 and 60 days and another two groups that received 1 g of UDCA per 100 g of standard diet during 30 and 60 days. After ether anaesthesia the gallbladder was removed and bile was immediately aspirated. Bile acids were determined by high performance liquid chromatography (HPLC). Taurolithocholic (TLCA) and glycolithocholic acids (GLCA) increased significantly in all treated groups. The glyco/tauro ratio of 0.69 in controls became more than 1 in treated animals except in the case of lithocholic acid (LCA) conjugates which remained less than 1. UDCA derivatives increased proportionally to the administered dose and the cholic/cheno ratio diminished significantly. A moderate increase of 3- and 7-keto derivatives of chenodeoxycholic acid (CDCA) was observed in all treated groups but the above mentioned increment was especially evident in 3-keto derivatives. A high percentage of UDCA administered in the hamster was likely transformed to CDCA and the glyco conjugates of the bile acids were the predominant species except for the LCA derivatives. PMID:2367280

  5. Intracellular delivery of desulfated heparin with bile acid conjugation alleviates T cell-mediated inflammatory arthritis via inhibition of RhoA-dependent transcellular diapedesis.

    PubMed

    Kang, Jin Hee; Hwang, Seung Rim; Sung, Shijin; Jang, Ji Ae; Alam, Md Mahmudul; Sa, Keum Hee; Kim, Sang-Yeob; Kim, In San; Byun, Young Ro; Kang, Young Mo

    2014-06-10

    Heparin has a potential regulatory role in inflammatory diseases. However, the anticoagulant activity and poor oral bioavailability of heparin limit its use as an anti-inflammatory agent. Conjugation of bis-deoxycholic acid to 6-O-desulfated low molecular weight heparin (6DSHbD) was efficiently internalized by activated endothelial cells via a 2-step model, in which heparin attaches to adhesion molecules that facilitate accessibility of the bile acid conjugate to membrane transporters. The critical role of P-selectin during endothelial cell uptake of 6DSHbD by arthritic tissue was confirmed in p-selectin(-/-) arthritic mice. Intracellular 6DSHbD inhibited transcellular diapedesis of T cells through activated endothelial cells and impaired both the formation of ICAM-1-rich docking structures at the T cell contact surface and subsequent cytoskeletal rearrangement. Furthermore, 6DSHbD blocked activation of RhoA-GTPase and phosphorylation of ezrin/radixin/moesin induced by ICAM-1 cross-linking on activated endothelial cells, thereby impairing lymphocyte transcellular transmigration. After oral administration 6DSHbD was preferentially delivered to inflamed joint tissue, particularly in and around post-capillary venular endothelium and inhibited effector T cell homing to arthritic joints. Aggravation of collagen-induced arthritis conferred by the transfer of effector T cells was suppressed by oral 6DSHbD. Thus, intracellular heparin exerts anti-inflammatory effects through the inhibition of RhoA-dependent transendothelial recruitment of T cells and may have applications in the treatment of chronic inflammatory arthritis. PMID:24657949

  6. Alteration of bile acid metabolism in the rat induced by chronic ethanol consumption

    PubMed Central

    Xie, Guoxiang; Zhong, Wei; Li, Houkai; Li, Qiong; Qiu, Yunping; Zheng, Xiaojiao; Chen, Huiyuan; Zhao, Xueqing; Zhang, Shucha; Zhou, Zhanxiang; Zeisel, Steven H.; Jia, Wei

    2013-01-01

    Our understanding of the bile acid metabolism is limited by the fact that previous analyses have primarily focused on a selected few circulating bile acids; the bile acid profiles of the liver and gastrointestinal tract pools are rarely investigated. Here, we determined how chronic ethanol consumption altered the bile acids in multiple body compartments (liver, gastrointestinal tract, and serum) of rats. Rats were fed a modified Lieber-DeCarli liquid diet with 38% of calories as ethanol (the amount equivalent of 4–5 drinks in humans). While conjugated bile acids predominated in the liver (98.3%), duodenum (97.8%), and ileum (89.7%), unconjugated bile acids comprised the largest proportion of measured bile acids in serum (81.2%), the cecum (97.7%), and the rectum (97.5%). In particular, taurine-conjugated bile acids were significantly decreased in the liver and gastrointestinal tract of ethanol-treated rats, while unconjugated and glycine-conjugated species increased. Ethanol consumption caused increased expression of genes involved in bile acid biosynthesis, efflux transport, and reduced expression of genes regulating bile acid influx transport in the liver. These results provide an improved understanding of the systemic modulations of bile acid metabolism in mammals through the gut-liver axis.—Xie, G., Zhong, W., Li, H., Li, Q., Qiu, Y., Zheng, X., Chen, H., Zhao, X., Zhang, S., Zhou, Z., Zeisel, S. H., Jia, W. Alteration of bile acid metabolism in the rat induced by chronic ethanol consumption. PMID:23709616

  7. Impaired Bile Acid Homeostasis in Children with Severe Acute Malnutrition

    PubMed Central

    Zhang, Ling; Voskuijl, Wieger; Mouzaki, Marialena; Groen, Albert K.; Alexander, Jennifer; Bourdon, Celine; Wang, Alice; Versloot, Christian J.; Di Giovanni, Valeria; Wanders, Ronald J. A.; Bandsma, Robert

    2016-01-01

    Objective Severe acute malnutrition (SAM) is a major cause of mortality in children under 5 years and is associated with hepatic steatosis. Bile acids are synthesized in the liver and participate in dietary fat digestion, regulation of energy expenditure, and immune responses. The aim of this work was to investigate whether SAM is associated with clinically relevant changes in bile acid homeostasis. Design An initial discovery cohort with 5 healthy controls and 22 SAM-patients was used to identify altered bile acid homeostasis. A follow up cohort of 40 SAM-patients were then studied on admission and 3 days after clinical stabilization to assess recovery in bile acid metabolism. Recruited children were 6–60 months old and admitted for SAM in Malawi. Clinical characteristics, feces and blood were collected on admission and prior to discharge. Bile acids, 7α-hydroxy-4-cholesten-3-one (C4) and FGF-19 were quantified. Results On admission, total serum bile acids were higher in children with SAM than in healthy controls and glycine-conjugates accounted for most of this accumulation with median and interquartile range (IQR) of 24.6 μmol/L [8.6–47.7] compared to 1.9 μmol/L [1.7–3.3] (p = 0.01) in controls. Total serum bile acid concentrations did not decrease prior to discharge. On admission, fecal conjugated bile acids were lower and secondary bile acids higher at admission compared to pre- discharge, suggesting increased bacterial conversion. FGF19 (Fibroblast growth factor 19), a marker of intestinal bile acid signaling, was higher on admission and was associated with decreased C4 concentrations as a marker of bile acid synthesis. Upon recovery, fecal calprotectin, a marker of intestinal inflammation, was lower. Conclusion SAM is associated with increased serum bile acid levels despite reduced synthesis rates. In SAM, there tends to be increased deconjugation of bile acids and conversion from primary to secondary bile acids, which may contribute to the

  8. Separation by thin-layer chromatography and structure elucidation of bilirubin conjugates isolated from dog bile.

    PubMed Central

    Heirwegh, K P; Fevery, J; Michiels, R; van Hees, G P; Compernolle, F

    1975-01-01

    1. A system for separation of bile pigments by t.l.c. and for their structure elucidation is presented. Separated bile pigments are characterized by t.l.c. of derived dipyrrolic azopigments. 2. At the tetrapyrrolic stage hydrolysis in strongly alkaline medium followed by t.l.c. demonstrates the presence of bilirubin-IIIalpha, -IXalpha and -XIIIalpha and allows assessment of their relative amounts. 3. Most structural information is derived from analysis of dipyrrolic azopigments. Such derivatives, obtained by treatment of separated bile pigments with diazotized ethyl anthranilate, were separated and purified by t.l.c. Micro methods showed (a) the nature of the dipyrrolic aglycone, (b) the nature of the bonds connecting aglycone to a conjugating group, (c) the ratio of vinyl/isovinyl isomers present in the aglycone and, (d) the nature of the conjugating groups (by suitable derivative formation and t.l.c. with reference to known compounds). 4. In bile of normal dogs at least 20 tetrapyrrolic, diazo-positive bile pigments could be recognized. Except for two pigments the tetrapyrrolic nucleus corresponded predominantly to bilirubin-IXalpha. All conjugated pigments had their conjugating groups connected in ester linkage to the tetrapyrrolic aglycone, Apart from bilirubin-IXalpha, monoconjugates and homogeneous and mixed diconjugates of bilirubin were demonstrated; conjugating groups of major importance were xylose, glucose and glucuronic acid. 5. Bilirubin isomer determination on native bile and isolated bile pigments, and dipyrrole-exchange assays with [14C8]bilirubin indicated (a) that the conjugates pre-exist in bile, and (b) that no significant dipyrrole exchange occurs during isolation of the pigments. PMID:1156357

  9. Structure and functional characterization of a bile acid 7α dehydratase BaiE in secondary bile acid synthesis.

    PubMed

    Bhowmik, Shiva; Chiu, Hsien-Po; Jones, David H; Chiu, Hsiu-Ju; Miller, Mitchell D; Xu, Qingping; Farr, Carol L; Ridlon, Jason M; Wells, James E; Elsliger, Marc-André; Wilson, Ian A; Hylemon, Phillip B; Lesley, Scott A

    2016-03-01

    Conversion of the primary bile acids cholic acid (CA) and chenodeoxycholic acid (CDCA) to the secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA) is performed by a few species of intestinal bacteria in the genus Clostridium through a multistep biochemical pathway that removes a 7α-hydroxyl group. The rate-determining enzyme in this pathway is bile acid 7α-dehydratase (baiE). In this study, crystal structures of apo-BaiE and its putative product-bound [3-oxo-Δ(4,6) -lithocholyl-Coenzyme A (CoA)] complex are reported. BaiE is a trimer with a twisted α + β barrel fold with similarity to the Nuclear Transport Factor 2 (NTF2) superfamily. Tyr30, Asp35, and His83 form a catalytic triad that is conserved across this family. Site-directed mutagenesis of BaiE from Clostridium scindens VPI 12708 confirm that these residues are essential for catalysis and also the importance of other conserved residues, Tyr54 and Arg146, which are involved in substrate binding and affect catalytic turnover. Steady-state kinetic studies reveal that the BaiE homologs are able to turn over 3-oxo-Δ(4) -bile acid and CoA-conjugated 3-oxo-Δ(4) -bile acid substrates with comparable efficiency questioning the role of CoA-conjugation in the bile acid metabolism pathway. PMID:26650892

  10. Ursodeoxycholic acid in the Ursidae: biliary bile acids of bears, pandas, and related carnivores.

    PubMed

    Hagey, L R; Crombie, D L; Espinosa, E; Carey, M C; Igimi, H; Hofmann, A F

    1993-11-01

    The biliary bile acid composition of gallbladder bile obtained from six species of bears (Ursidae), the Giant panda, the Red panda, and 11 related carnivores were determined by reversed phase liquid chromatography and gas chromatography-mass spectrometry. Bile acids were conjugated solely with taurine (in N-acyl linkage) in all species. Ursodeoxycholic acid (3 alpha, 7 beta-dihydroxy-5 beta-cholan-24-oic acid) was present in all Ursidae, averaging 1-39% of biliary bile acids depending on the species; it was not detected or present as a trace constituent (< 0.5%) in all other species, including the Giant panda. Ursodeoxycholic acid was present in 73 of 75 American Black bears, and its proportion averaged 34% (range 0-62%). Ursodeoxycholic acid averaged 17% of biliary bile acids in the Polar bear (n = 4) and 18% in the Brown bear (n = 6). Lower proportions (1-8%) were present in the Sun bear (n = 2), Ceylon Sloth bear (n = 1), and the Spectacled bear (n = 1). Bile of all species contained taurine-conjugated chenodeoxycholic acid and cholic acid. In some related carnivores, deoxycholic acid, the 7-dehydroxylation product of cholic acid, was also present. To determine whether the 7 beta hydroxy group of ursodeoxycholic acid was formed by hepatic or bacterial enzymes, bile acids were determined in hepatic bile obtained from bears with chronic biliary fistulae. Fistula bile samples contained ursodeoxycholic acid, chenodeoxycholic acid, and a trace amount of cholic acid, all as taurine conjugates, indicating that ursodeoxycholic acid is a primary bile acid formed in the liver in Ursidae.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8263415

  11. Novel, major 2α- and 2β-hydroxy bile alcohols and bile acids in the bile of Arapaima gigas, a large South American river fish.

    PubMed

    Sato née Okihara, Rika; Saito, Tetsuya; Ogata, Hiroaki; Nakane, Naoya; Namegawa, Kazunari; Sekiguchi, Shoutaro; Omura, Kaoru; Kurabuchi, Satoshi; Mitamura, Kuniko; Ikegawa, Shigeo; Raines, Jan; Hagey, Lee R; Hofmann, Alan F; Iida, Takashi

    2016-03-01

    Bile alcohols and bile acids from gallbladder bile of the Arapaima gigas, a large South American freshwater fish, were isolated by reversed-phase high-performance liquid chromatography. The structures of the major isolated compounds were determined by electrospray-tandem mass spectrometry and nuclear magnetic resonance using (1)H- and (13)C-NMR spectra. The novel bile salts identified were six variants of 2-hydroxy bile acids and bile alcohols in the 5α- and 5β-series, with 29% of all compounds having hydroxylation at C-2. Three C27 bile alcohols were present (as ester sulfates): (24ξ,25ξ)-5α-cholestan-2α,3α,7α,12α,24,26-hexol; (25ξ)-5β-cholestan-2β,3α,7α,12α,26,27-hexol, and (25ξ)-5α-cholestan-2α,3α,7α,12α,26,27-hexol. A single C27 bile acid was identified: (25ξ)-2α,3α,7α,12α-tetrahydroxy-5α-cholestan-26-oic acid, present as its taurine conjugate. Two novel C24 bile acids were identified: the 2α-hydroxy derivative of allochenodeoxycholic acid and the 2β-hydroxy derivative of cholic acid, both occurring as taurine conjugates. These studies extend previous work in establishing the natural occurrence of novel 2α- and 2β-hydroxy-C24 and C27 bile acids as well as C27 bile alcohols in both the normal (5β) as well as the (5α) "allo" A/B-ring juncture. The bile salt profile of A. gigas appears to be unique among vertebrates. PMID:26768415

  12. Olfactory sensitivity to bile acids in salmonid fishes.

    PubMed

    Døving, K B; Selset, R; Thommesen, G

    1980-02-01

    Monopolar DC-recordings were made simultaneously from two positions on the olfactory bulb of chars (Salmo alpinus L.) and graylings (Thymallus thymallu L.) using bile acids and amino acids as olfactory stimulants. The bile acids induced responses with characteristic spatial differences from those of the amino acids. The distribution of responses to bile acids indicated a neuronal activity in the medial part of the bulb. In contrast, amino acids elicit responses in the lateral part of the bulb. Taurine conjugated bile acids were up to 1 000 times more potent as olfactory stimuli than methionine. The results suggest that olfactory receptors are of two types, one responding to bile acids, the other to amino acids. 3 -alpha-hydroxysteroids are released from the fish into the water in quantities that suffice for detection by their olfactory system. The odorant potency of the bile acids, their evolutionary history and variability, together with their renowned adherent properties made them interesting candidates for specific signals in the acquatic environment. PMID:7376910

  13. HPLC-fluorescence determination of bile acids in pharmaceuticals and bile after derivatization with 2-bromoacetyl-6-methoxynaphthalene.

    PubMed

    Cavrini, V; Gatti, R; Roda, A; Cerrè, C; Roveri, P

    1993-08-01

    2-Bromoacetyl-6-methoxynaphthalene was used as a pre-chromatographic fluorescent labelling reagent for the high-performance liquid chromatographic (HPLC) analysis of bile acids. The derivatization reaction was performed in an aqueous medium in the presence of tetrahexylammonium bromide by ultrasonication at 40 degrees C to give fluorescent esters which were separated by reversed-phase HPLC and detected fluorimetrically (lambda ex = 300 nm, lambda em = 460 nm). Applications to the determination of ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) in their pharmaceutical formulations are described. The method was also applied to the determination of free and conjugated bile acids in human bile samples. PMID:8257742

  14. 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

  15. Human liver steroid sulphotransferase sulphates bile acids.

    PubMed Central

    Radominska, A; Comer, K A; Zimniak, P; Falany, J; Iscan, M; Falany, C N

    1990-01-01

    The sulphation of bile acids is an important pathway for the detoxification and elimination of bile acids during cholestatic liver disease. A dehydroepiandrosterone (DHEA) sulphotransferase has been purified from male and female human liver cytosol using DEAE-Sepharose CL-6B and adenosine 3',5'-diphosphate-agarose affinity chromatography [Falany, Vazquez & Kalb (1989) Biochem. J. 260, 641-646]. Results in the present paper show that the DHEA sulphotransferase, purified to homogeneity, is also reactive towards bile acids, including lithocholic acid and 6-hydroxylated bile acids, as well as 3-hydroxylated short-chain bile acids. The highest activity towards bile acids was observed with lithocholic acid (54.3 +/- 3.6 nmol/min per mg of protein); of the substrates tested, the lowest activity was detected with hyodeoxycholic acid (4.2 +/- 0.01 nmol/min per mg of protein). The apparent Km values for the enzyme are 1.5 +/- 0.31 microM for lithocholic acid and 4.2 +/- 0.73 microM for taurolithocholic acid. Lithocholic acid also competitively inhibits DHEA sulphation by the purified sulphotransferase (Ki 1.4 microM). No evidence was found for the formation of bile acid sulphates by sulphotransferases different from the DHEA sulphotransferase during purification work. The above results suggest that a single steroid sulphotransferase with broad specificity encompassing neutral steroids and bile acids exists in human liver. PMID:2268288

  16. Individual bile acids have differential effects on bile acid signaling in mice

    SciTech Connect

    Song, Peizhen Rockwell, Cheryl E. Cui, Julia Yue Klaassen, Curtis D.

    2015-02-15

    Bile acids (BAs) are known to regulate BA synthesis and transport by the farnesoid X receptor in the liver (FXR-SHP) and intestine (FXR-Fgf15). However, the relative importance of individual BAs in regulating these processes is not known. Therefore, mice were fed various doses of five individual BAs, including cholic acid (CA), chenodeoxycholic acid (CDCA), deoxoycholic acid (DCA), lithocholic acid (LCA), and ursodeoxycholic acid (UDCA) in their diets at various concentrations for one week to increase the concentration of one BA in the enterohepatic circulation. The mRNA of BA synthesis and transporting genes in liver and ileum were quantified. In the liver, the mRNA of SHP, which is the prototypical target gene of FXR, increased in mice fed all concentrations of BAs. In the ileum, the mRNA of the intestinal FXR target gene Fgf15 was increased at lower doses and to a higher extent by CA and DCA than by CDCA and LCA. Cyp7a1, the rate-limiting enzyme in BA synthesis, was decreased more by CA and DCA than CDCA and LCA. Cyp8b1, the enzyme that 12-hydroxylates BAs and is thus responsible for the synthesis of CA, was decreased much more by CA and DCA than CDCA and LCA. Surprisingly, neither a decrease in the conjugated BA uptake transporter (Ntcp) nor increase in BA efflux transporter (Bsep) was observed by FXR activation, but an increase in the cholesterol efflux transporter (Abcg5/Abcg8) was observed with FXR activation. Thus in conclusion, CA and DCA are more potent FXR activators than CDCA and LCA when fed to mice, and thus they are more effective in decreasing the expression of the rate limiting gene in BA synthesis Cyp7a1 and the 12-hydroxylation of BAs Cyp8b1, and are also more effective in increasing the expression of Abcg5/Abcg8, which is responsible for biliary cholesterol excretion. However, feeding BAs do not alter the mRNA or protein levels of Ntcp or Bsep, suggesting that the uptake or efflux of BAs is not regulated by FXR at physiological and

  17. 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

    2011-01-01

    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

  18. Quantitative microanalysis of bile acids in biological samples. Collaborative study.

    PubMed

    Nakayama, F

    1988-10-28

    The analysis of bile acids in biological samples has always presented a problem because of their complex nature and low concentration. Recently, newer analytical procedures for bile acids have become available, including enzymatic analysis, radioimmunoassay, thin-layer chromatography (TLC), gas chromatography, high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring (SIM). However, they differ greatly with respect to specificity, sensitivity, accuracy and simplicity. On the other hand, the choice of analytical procedure differs according to the specific aims and the nature of biological samples to be analysed. These newer procedures have been compared in a double-blind fashion by distributing bile, plasma and urine samples to seven participating laboratories. GC-MS-SIM was found to be the most sensitive and reliable, but it requires other procedures for preliminary clean-up and fractionation steps. Enzymatic analysis is simple and gives small analytical errors but tends to over-estimate plasma bile acids. Radioimmunoassay gives variable results but is useful as a screening procedure for large numbers of plasma samples. TLC gives reliable results for biliary bile acids in experienced hands, except for differentiation between conjugated dihydroxycholanoic acids. HPLC, whether using derivatization or with fixed 3 alpha-hydroxy steroid dehydrogenase detection, is suitable for the analysis of major bile acids in normal human serum but not for the identification of unknown minor peaks. PMID:3243854

  19. The effect of bile, bile acids and detergents on calcium absorption in the chick

    PubMed Central

    Webling, D. D'A.; Holdsworth, E. S.

    1965-01-01

    1. Bile from rachitic or normal chicks causes an immediate increase in the intestinal absorption of soluble calcium in rachitic and vitamin D3-treated chicks as tested in vivo by intestinal-loop and oral-dosing methods. 2. This effect is apparently solely due to the taurine-conjugated bile acids present in the bile and is independent of the action of vitamin D. 3. Chick bile and bile acids can increase the solubility and the absorption of calcium presented as sparingly soluble calcium hydrogen phosphate. 4. In addition, bile is necessary to some extent at least for the intestinal absorption of vitamin D3 in the chick and this would indirectly enhance the absorption of calcium. 5. Thus bile is capable of a threefold action in the absorption of calcium in the chick. It is suggested that the direct action on sparingly soluble forms of calcium is of considerable physiological importance since most of the calcium in the normal bird's diet would be in this form. 6. Bile acids enhance the absorption of calcium in all regions of the small intestine of the chick. 7. Of a range of bile acids and detergents tested for enhancement of calcium absorption, various taurine-conjugated bile acids and sodium lauryl sulphate, an anionic detergent, are effective. A non-ionic detergent (Tween 80) and a cationic detergent (Zephiran) are without effect. 8. The ability of a substance to increase directly the intestinal absorption of soluble calcium appears to depend to some extent on an anionic detergent action, i.e. the ability to form a salt or complex soluble to some extent in both aqueous and lipid phases. 9. In chicks the immediate deposition of calcium (45Ca) in the bones closely reflects any increase in plasma calcium radioactivity regardless of the cause of the increase and regardless of the vitamin D3 status. Although sodium lauryl sulphate can increase markedly the calcium absorption from the gut and the immediate deposition in the bones it has no significant effect on rickets

  20. Genetics Home Reference: congenital bile acid synthesis defect type 1

    MedlinePlus

    ... bile acid synthesis defect type 1 congenital bile acid synthesis defect type 1 Enable Javascript to view ... PDF Open All Close All Description Congenital bile acid synthesis defect type 1 is a disorder characterized ...

  1. Genetics Home Reference: congenital bile acid synthesis defect type 2

    MedlinePlus

    ... bile acid synthesis defect type 2 congenital bile acid synthesis defect type 2 Enable Javascript to view ... PDF Open All Close All Description Congenital bile acid synthesis defect type 2 is a disorder characterized ...

  2. Circadian dysregulation disrupts bile acid homeostasis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    SciTech Connect

    Woolbright, Benjamin L.; Dorko, Kenneth; Antoine, Daniel J.; Clarke, Joanna I.; Gholami, Parviz; Li, Feng; Kumer, Sean C.; Schmitt, Timothy M.; Forster, Jameson; Fan, Fang; Jenkins, Rosalind E.; Park, B. Kevin; Hagenbuch, Bruno; Olyaee, Mojtaba; Jaeschke, Hartmut

    2015-03-15

    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, 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

  4. Bile Acid Metabolome after an Oral Lipid Tolerance Test by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

    PubMed Central

    Schmid, Andreas; Neumann, Hannah; Karrasch, Thomas; Liebisch, Gerhard; Schäffler, Andreas

    2016-01-01

    Context Besides their role in intestinal resorption of lipids, bile acids are regarded as endocrine and metabolic signaling molecules. The detailed profile of bile acid species in peripheral blood after an oral lipid tolerance test (OLTT) is unknown. Objective We quantified the regulation of 18 bile acids after OLTT in healthy individuals. Material and methods 100 volunteers were characterized by anthropometric and laboratory parameters and underwent OLTT. Venous blood was drawn in the fasted state (0 h) and at 2h, 4h, and 6 h after OLTT. Serum concentrations of 18 bile acids were measured by LC-MS/MS. Results All of the 6 taurine-conjugated bile acids (TUDCA, THDCA, TCA, TCDCA, TDCA, TLCA) and all of the 6 glycine-conjugated bile acids (GUDCA, GHDCA, GCA, GCDCA, GDCA, GLCA) rose significantly at 2h and remained elevated during OLTT. Of the primary bile acids, CA remained unchanged, whereas CDCA significantly decreased at 4h. Of the secondary bile acids, DCA, UDCA and HDCA were not altered, whereas LCA decreased. There was a significant positive correlation between the intestinal feed-back regulator of bile acid synthesis FGF-19 and bile acids. This correlation seems to depend on all of the six taurine-conjugated bile acids and on GCA, GDCA, and GCDCA. Females and users of hormonal contraception displayed higher levels of taurine-conjugated bile acids. Conclusions The novelty of the study is based on the identification of single bile acids during OLTT. LC-MS/MS-based quantification of bile acids in serum provides a reliable tool for future investigation of endocrine and metabolic effects of bile acids. PMID:26863103

  5. Bile acids in radiation-induced diarrhea

    SciTech Connect

    Arlow, F.L.; Dekovich, A.A.; Priest, R.J.; Beher, W.T.

    1987-10-01

    Radiation-induced bowel disease manifested by debilitating diarrhea is an unfortunate consequence of therapeutic irradiation for pelvic malignancies. Although the mechanism for this diarrhea is not well understood, many believe it is the result of damage to small bowel mucosa and subsequent bile acid malabsorption. Excess amounts of bile acids, especially the dihydroxy components, are known to induce water and electrolyte secretion and increase bowel motility. We have directly measured individual and total bile acids in the stool samples of 11 patients with radiation-induced diarrhea and have found bile acids elevated two to six times normal in eight of them. Our patients with diarrhea and increased bile acids in their stools had prompt improvement when given cholestyramine. They had fewer stools and returned to a more normal life-style.

  6. Bile acid dissolution therapy of gallbladder stones.

    PubMed

    Fromm, H; Malavolti, M

    1992-11-01

    Oral cholelitholytic bile acid therapy has become established treatment for selected patients with cholesterol gallstones. The treatment finds its clinical application both alone and in combination with ESWL. UDCA alone or, less commonly, a combination of this bile acid with CDCA is used. Optimal results can be expected only in carefully selected patients. Bile acid dissolution therapy is most successful in patients with radiolucent gallstones which are < or = 0.5 cm in diameter or are shown by OCG to be floating. Dissolution is seldom seen when the stones are > 1 cm in size. Cholelitholytic treatment in combination with ESWL yields optimal results in single radiolucent gallstones which are not greater than 2 cm. ESWL thus makes it possible to use medical treatment effectively in single 1-2 cm gallstones when bile acids alone would not be successful. Bile acid treatment is extremely safe, especially if UDCA is given without the addition of CDCA. PMID:1486209

  7. Biliary bile acids in primary biliary cirrhosis: effect of ursodeoxycholic acid.

    PubMed

    Combes, B; Carithers, R L; Maddrey, W C; Munoz, S; Garcia-Tsao, G; Bonner, G F; Boyer, J L; Luketic, V A; Shiffman, M L; Peters, M G; White, H; Zetterman, R K; Risser, R; Rossi, S S; Hofmann, A F

    1999-06-01

    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

  8. Transport, metabolism, and effect of chronic feeding of lagodeoxycholic acid. A new, natural bile acid.

    PubMed

    Schmassmann, A; Angellotti, M A; Clerici, C; Hofmann, A F; Ton-Nu, H T; Schteingart, C D; Marcus, S N; Hagey, L R; Rossi, S S; Aigner, A

    1990-10-01

    Ursodeoxycholic acid, the 7 beta-hydroxy epimer of chenodeoxycholic acid, is more hydrophilic and less hepatotoxic than chenodeoxycholic acid. Because "lagodeoxycholic acid," the 12 beta-hydroxy epimer of deoxycholic acid, is also more hydrophilic than deoxycholic acid, it was hypothesized that it should also be less hepatotoxic than deoxycholic acid. To test this, lagodeoxycholic acid was synthesized, and its transport and metabolism were examined in the rat, rabbit, and hamster. The taurine conjugate of lagodeoxycholic acid was moderately well transported by the perfused rat ileum (Tmax = 2 mumol/min.kg). In rats and hamsters with biliary fistulas, the taurine conjugate of lagodeoxycholic acid was well transported by the liver with a Tmax greater than 20 mumol/min.kg; for the taurine conjugate of deoxycholic acid, doses infused at a rate greater than 2.5 mumol/min.kg are known to cause cholestasis and death. Hepatic biotransformation of lagodeoxycholic acid in the rabbit was limited to conjugation with glycine; in the hamster, lagodeoxycholic acid was conjugated with glycine or taurine; in addition, 7-hydroxylation occurred to a slight extent (approximately 10%). When lagodeoxycholic acid was instilled in the rabbit colon, it was absorbed as such although within hours it was progressively epimerized by bacteria to deoxycholic acid. When injected intravenously and allowed to circulate enterohepatically, lagodeoxycholic acid was largely epimerized to deoxycholic acid in 24 hours. Surgical creation of a distal ileostomy abolished epimerization in the rabbit, indicating that exposure to colonic bacterial enzymes was required for the epimerization. Lagodeoxycholic acid was administered for 3 weeks at a dose of 180 mumol/day (0.1% by weight of a chow diet; 2-4 times the endogenous bile acid synthesis rate); other groups received identical doses of deoxycholic acid (hamster) or cholyltaurine, a known precursor of deoxycholic acid (rabbit). After 3 weeks of

  9. Protection of live bacteria from bile acid toxicity using bile acid adsorbing resins.

    PubMed

    Edwards, Alexander D; Slater, Nigel K H

    2009-06-12

    We previously demonstrated that a dry, room temperature stable formulation of a live bacterial vaccine was highly susceptible to bile, and suggested that this will lead to significant loss of viability of any live bacterial formulation released into the intestine using an enteric coating or capsule. We found that bile and acid tolerance is very rapidly recovered after rehydration with buffer or water, raising the possibility that rehydration in the absence of bile prior to release into the intestine might solve the problem of bile toxicity to dried cells. We describe here a novel formulation that combines extensively studied bile acid adsorbent resins with the dried bacteria, to temporarily adsorb bile acids and allow rehydration and recovery of bile resistance of bacteria in the intestine before release. Tablets containing the bile acid adsorbent cholestyramine release 250-fold more live bacteria when dissolved in a bile solution, compared to control tablets without cholestyramine or with a control resin that does not bind bile acids. We propose that a simple enteric coated oral dosage form containing bile acid adsorbent resins will allow improved live bacterial delivery to the intestine via the oral route, a major step towards room temperature stable, easily administered and distributed vaccine pills and other bacterial therapeutics. PMID:19490986

  10. Bile acid signaling and biliary functions

    PubMed Central

    Jones, Hannah; Alpini, Gianfranco; Francis, Heather

    2015-01-01

    This review focuses on various components of bile acid signaling in relation to cholangiocytes. Their roles as targets for potential therapies for cholangiopathies are also explored. While many factors are involved in these complex signaling pathways, this review emphasizes the roles of transmembrane G protein coupled receptor (TGR5), farnesoid X receptor (FXR), ursodeoxycholic acid (UDCA) and the bicarbonate umbrella. Following a general background on cholangiocytes and bile acids, we will expand the review and include sections that are most recently known (within 5–7 years) regarding the field of bile acid signaling and cholangiocyte function. These findings all demonstrate that bile acids influence biliary functions which can, in turn, regulate the cholangiocyte response during pathological events. PMID:26579437

  11. Nuclear receptors, bile acids and cholesterol homeostasis series - bile acids and pregnancy.

    PubMed

    Abu-Hayyeh, Shadi; Papacleovoulou, Georgia; Williamson, Catherine

    2013-04-10

    Bile acids have been traditionally thought of as having an important role in fat emulsification. It is now emerging that they act as important signalling molecules that not only autoregulate their own synthesis but also influence lipid and glucose metabolism. Although, the mechanisms that underlie the regulation of bile acid homeostasis have been well characterised in normal physiology, the impact of pregnancy on bile acid regulation is still poorly understood. This review summarises the main regulatory mechanisms underlying bile acid homeostasis and discusses how pregnancy, a unique physiological state, can modify them. The fetoplacental adaptations that protect against fetal bile acid toxicity are reviewed. We highlight the importance of bile acid regulation during gestation by discussing the liver disease of pregnancy, intrahepatic cholestasis of pregnancy (ICP) and how genetic, endocrine and environmental factors contribute to the disease aetiology at a cellular and molecular level. PMID:23159988

  12. Quantitative profiling of bile acids in rat bile using ultrahigh-performance liquid chromatography-orbitrap mass spectrometry: Alteration of the bile acid composition with aging.

    PubMed

    Lee, Gakyung; Lee, Hyunbeom; Hong, Jongki; Lee, Soo Hyun; Jung, Byung Hwa

    2016-09-15

    Bile acids (BAs) play important roles in physiological functions, including the homeostasis of cholesterol and lipids and as ligands for G protein-coupled receptors (GPCRs). With the increasing importance of BAs, analytical methods for their quantification and screening have been developed. However, due to the diverse range and variety of BAs with different activation potency, a simple, effective, and sensitive method is required to screen BAs for accurate quantification and identification. This paper presents an application of ultrahigh-performance liquid chromatography-orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap MS) for profiling BAs in bile. Using this method, along with the accurate quantification of 19 targeted BAs, 22 unknown BAs were detected and characterized by their fragmentation patterns. The method is beneficial for screening most of the BAs (quantitatively and qualitatively) in rat bile with simple preparation in a single run. The sample dilution ranges of each BA were optimized depending on the concentration of BAs in the bile to obtain good peak separation and accurate data. The method validation was performed successfully using charcoal-treated bile and the intra and inter-day coefficients of variation were less than 20% for all BAs while the recovery were above 88.5% except for the lithocholic acid. The method was applied to profile the age-dependent changes in the contents of rat BAs. Through statistical analysis, we found that as the rats aged, unconjugated BAs and glycine-conjugated BAs decreased or were unaffected, while taurine-conjugated BAs were increased in general. Among the unknown BAs, 5 of the taurine-conjugated BAs increased, while a glycine-conjugated BA decreased, in agreement with the trends of the targeted BAs. PMID:27450898

  13. Chemical synthesis of the 3-sulfooxy-7-N-acetylglucosaminyl-24-amidated conjugates of 3beta,7beta-dihydroxy-5-cholen-24-oic acid, and related compounds: unusual, major metabolites of bile acid in a patient with Niemann-Pick disease type C1.

    PubMed

    Iida, Takashi; Kakiyama, Genta; Hibiya, Yohei; Miyata, Shohei; Inoue, Takehiko; Ohno, Kohsaku; Goto, Takaaki; Mano, Nariyasu; Goto, Junichi; Nambara, Toshio; Hofmann, Alan F

    2006-01-01

    The chemical synthesis of 3beta,7beta-dihydroxy-5-cholen-24-oic acid, triply conjugated by sulfuric acid at C-3, by N-acetylglucosamine (GlcNAc) at C-7, and by glycine or taurine at C-24, is described. These are unusual, major metabolites of bile acid found to be excreted in the urine of a patient with Niemann-Pick disease type C1. Analogous double-conjugates of 3beta-hydroxy-7-oxo-5-cholen-24-oic acid were also prepared. The principal reactions involved were: (1) beta-d-N-acetylglucosaminidation at C-7 of methyl 3beta-tert-butyldimethylsilyloxy (TBDMSi)-7beta-hydroxy-5-cholen-24-oate with 2-acetamido-1alpha-chloro-1,2-dideoxy-3,4,6-tri-O-acetyl-d-glucopyranose in the presence of CdCO(3) in boiling toluene; (2) sulfation at C-3 of the resulting 3beta-TBDMSi-7beta-GlcNAc with sulfur trioxide-trimethylamine complex in pyridine; and (3) direct amidation at C-24 of the 3beta-sulfooxy-7beta-GlcNAc conjugate with glycine methyl ester hydrochloride (or taurine) using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride as a coupling agent in DMF. The structures of the multi-conjugated bile acids were characterized by liquid chromatography-mass spectrometry with an electrospray ionization probe under the positive and negative ionization modes. PMID:16197972

  14. Bile Acids Regulate Cardiovascular Function

    PubMed Central

    Khurana, Sandeep; Raufman, Jean-Pierre; Pallone, Thomas L.

    2011-01-01

    Research over the last decade has uncovered roles for bile acids (BAs) that extend beyond their traditional functions in regulating lipid digestion and cholesterol metabolism. BAs are now recognized as signaling molecules that interact with both plasma membrane and nuclear receptors. Emerging evidence indicates that by interacting with these receptors BAs regulate their own synthesis, glucose and energy homeostasis, and other important physiological events. Herein, we provide a comprehensive review of the actions of BAs on cardiovascular function. In the heart and the systemic circulation, BAs interact with plasma membrane G-protein coupled receptors, e.g. TGR5 and muscarinic receptors, and nuclear receptors, e.g. the farnesoid (FXR) and pregnane (PXR) xenobiotic receptors. BA receptors are expressed in cardiovascular tissue, however, the mechanisms underlying BA-mediated regulation of cardiovascular function remain poorly understood. BAs reduce heart rate by regulating channel conductance and calcium dynamics in sino-atrial and ventricular cardiomyocytes, and regulate vascular tone via both endothelium-dependent and -independent mechanisms. End-stage-liver disease, obstructive jaundice and intrahepatic cholestasis of pregnancy are prominent conditions in which elevated serum BAs alter vascular dynamics. This review focuses on BAs as newly-recognized signaling molecules that modulate cardiovascular function. PMID:21707953

  15. Bile Acid-Induced Necrosis in Primary Human Hepatocytes and in Patients with Obstructive Cholestasis

    PubMed Central

    Woolbright, Benjamin L.; Dorko, Kenneth; Antoine, Daniel J.; Clarke, Joanna I.; Gholami, Parviz; Li, Feng; Kumer, Sean C.; Schmitt, Timothy M.; Forster, Jameson; Fan, Fang; Jenkins, Rosalind E.; Park, B. Kevin; Hagenbuch, Bruno; Olyaee, Mojtaba; Jaeschke, Hartmut

    2015-01-01

    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, 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 box1 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. PMID:25636263

  16. Fifty years with bile acids and steroids in health and disease.

    PubMed

    Sjövall, Jan

    2004-08-01

    Cholesterol and its metabolites, e.g., steroid hormones and bile acids, constitute a class of compounds of great biological importance. Their chemistry, biochemistry, and regulation in the body have been intensely studied for more than two centuries. The author has studied aspects of the biochemistry and clinical chemistry of steroids and bile acids for more than 50 years, and this paper, which is an extended version of the Schroepfer Medal Award lecture, reviews and discusses part of this work. Development and application of analytical methods based on chromatography and mass spectrometry (MS) have been a central part of many projects, aiming at detailed characterization and quantification of metabolic profiles of steroids and bile acids under different conditions. In present terminology, much of the work may be termed steroidomics and cholanoidomics. Topics discussed are bile acids in human bile and feces, bile acid production, bacterial dehydroxylation of bile acids and steroids during the enterohepatic circulation, profiles of steroid sulfates in plasma of humans and other primates, development of neutral and ion-exchanging lipophilic derivatives of Sephadex for sample preparation and group separation of steroid and bile acid conjugates, profiles of steroids and bile acids in human urine under different conditions, hydroxylation of bile acids in liver disease, effects of alcohol-induced redox changes on steroid synthesis and metabolism, alcohol-induced changes of bile acid biosynthesis, compartmentation of bile acid synthesis studied with 3H-labeled ethanol, formation and metabolism of sulfated metabolites of progesterone in human pregnancy, abnormal patterns of these in patients with intrahepatic cholestasis of pregnancy corrected by ursodeoxycholic acid, inherited and acquired defects of bile acid biosynthesis and their treatment, conjugation of bile acids and steroids with N-acetylglucosamine, sulfate-glucuronide double conjugates of hydroxycholesterols

  17. Pharmacology of bile acid receptors: Evolution of bile acids from simple detergents to complex signaling molecules.

    PubMed

    Copple, Bryan L; Li, Tiangang

    2016-02-01

    For many years, bile acids were thought to only function as detergents which solubilize fats and facilitate the uptake of fat-soluble vitamins in the intestine. Many early observations; however, demonstrated that bile acids regulate more complex processes, such as bile acids synthesis and immune cell function through activation of signal transduction pathways. These studies were the first to suggest that receptors may exist for bile acids. Ultimately, seminal studies by many investigators led to the discovery of several bile acid-activated receptors including the farnesoid X receptor, the vitamin D receptor, the pregnane X receptor, TGR5, α5 β1 integrin, and sphingosine-1-phosphate receptor 2. Several of these receptors are expressed outside of the gastrointestinal system, indicating that bile acids may have diverse functions throughout the body. Characterization of the functions of these receptors over the last two decades has identified many important roles for these receptors in regulation of bile acid synthesis, transport, and detoxification; regulation of glucose utilization; regulation of fatty acid synthesis and oxidation; regulation of immune cell function; regulation of energy expenditure; and regulation of neural processes such as gastric motility. Through these many functions, bile acids regulate many aspects of digestion ranging from uptake of essential vitamins to proper utilization of nutrients. Accordingly, within a short time period, bile acids moved beyond simple detergents and into the realm of complex signaling molecules. Because of the important processes that bile acids regulate through activation of receptors, drugs that target these receptors are under development for the treatment of several diseases, including cholestatic liver disease and metabolic syndrome. In this review, we will describe the various bile acid receptors, the signal transduction pathways activated by these receptors, and briefly discuss the physiological processes that

  18. Taurine ameliorates cholesterol metabolism by stimulating bile acid production in high-cholesterol-fed rats.

    PubMed

    Murakami, Shigeru; Fujita, Michiko; Nakamura, Masakazu; Sakono, Masanobu; Nishizono, Shoko; Sato, Masao; Imaizumi, Katsumi; Mori, Mari; Fukuda, Nobuhiro

    2016-03-01

    This study was designed to investigate the effects of dietary taurine on cholesterol metabolism in high-cholesterol-fed rats. Male Sprague-Dawley rats were randomly divided into two dietary groups (n = 6 in each group): a high-cholesterol diet containing 0.5% cholesterol and 0.15% sodium cholate, and a high-cholesterol diet with 5% (w/w) taurine. The experimental diets were given for 2 weeks. Taurine supplementation reduced the serum and hepatic cholesterol levels by 37% and 32%, respectively. Faecal excretion of bile acids was significantly increased in taurine-treated rats, compared with untreated rats. Biliary bile acid concentrations were also increased by taurine. Taurine supplementation increased taurine-conjugated bile acids by 61% and decreased glycine-conjugated bile acids by 53%, resulting in a significant decrease in the glycine/taurine (G/T) ratio. Among the taurine-conjugated bile acids, cholic acid and deoxycholic acid were significantly increased. In the liver, taurine supplementation increased the mRNA expression and enzymatic activity of hepatic cholesterol 7α-hydroxylase (CYP7A1), the rate-limiting enzyme for bile acid synthesis, by three- and two-fold, respectively. Taurine also decreased the enzymatic activity of acyl-CoA:cholesterol acyltransferase (ACAT) and microsomal triglyceride transfer protein (MTP). These observations suggest that taurine supplementation increases the synthesis and excretion of taurine-conjugated bile acids and stimulates the catabolism of cholesterol to bile acid by elevating the expression and activity of CYP7A1. This may reduce cholesterol esterification and lipoprotein assembly for very low density lipoprotein (VLDL) secretion, leading to reductions in the serum and hepatic cholesterol levels. PMID:26710098

  19. 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

  20. Triketocholanoic (Dehydrocholic) Acid. HEPATIC METABOLISM AND EFFECT ON BILE FLOW AND BILIARY LIPID SECRETION IN MAN

    PubMed Central

    Soloway, Roger D.; Hofmann, Alan F.; Thomas, Paul J.; Schoenfield, Leslie J.; Klein, Peter D.

    1973-01-01

    [24-14C]Dehydrocholic acid (triketo-5-β-cholanoic acid) was synthesized from [24-14C]cholic acid, mixed with 200 mg of carrier, and administered intravenously to two patients with indwelling T tubes designed to permit bile sampling without interruption of the enterohepatic circulation. More than 80% of infused radioactivity was excreted rapidly in bile as glycine- and taurine-conjugated bile acids. Radioactive products were identified, after deconjugation, as partially or completely reduced derivatives of dehydrocholic acid. By mass spectrometry, as well as chromatography, the major metabolite (about 70%) was a dihydroxy monoketo bile acid (3α,7α-dihydroxy-12-keto-5β-cholanoic acid); a second metabolite (about 20%) was a monohydroxy diketo acid (3α-hydroxy-7,12-di-keto-5β-cholanoic acid); and about 10% of radioactivity was present as cholic acid. Reduction appeared to have been sequential (3 position, then 7 position, and then 12 position) and stereospecific (only α epimers were recovered). Bile flow, expressed as the ratio of bile flow to bile acid excretion, was increased after dehydrocholic acid administration. It was speculated that the hydroxy keto metabolites are hydrocholeretics. The proportion of cholesterol to lecithin and bile acids did not change significantly after dehydrocholic acid administration. In vitro studies showed that the hydroxy keto metabolites dispersed lecithin poorly compared to cholate; however, mixtures of cholate and either metabolite had dispersant properties similar to those of cholate alone, provided the ratio of metabolite to cholate remained below a value characteristic for each metabolite. These experiments disclose a new metabolic pathway in man, provide further insight into the hydrocholeresis induced by keto bile acids, and indicate the striking change in pharmacologic and physical properties caused by replacement of hydroxyl by a keto substituent in the bile acid molecule. Images PMID:4685091

  1. Gut microbiota, cirrhosis, and alcohol regulate bile acid metabolism in the gut.

    PubMed

    Ridlon, Jason M; Kang, Dae-Joong; Hylemon, Phillip B; Bajaj, Jasmohan S

    2015-01-01

    The understanding of the complex role of the bile acid-gut microbiome axis in health and disease processes is evolving rapidly. Our focus revolves around the interaction of the gut microbiota with liver diseases, especially cirrhosis. The bile acid pool size has recently been shown to be a function of microbial metabolism of bile acid, and regulation of the microbiota by bile acids is important in the development and progression of several liver diseases. Humans produce a large, conjugated hydrophilic bile acid pool, maintained through positive-feedback antagonism of farnesoid X receptor (FXR) in the intestine and liver. Microbes use bile acids, and via FXR signaling this results in a smaller, unconjugated hydrophobic bile acid pool. This equilibrium is critical to maintain health. The challenge is to examine the manifold functions of gut bile acids as modulators of antibiotic, probiotic, and disease progression in cirrhosis, metabolic syndrome, and alcohol use. Recent studies have shown potential mechanisms explaining how perturbations in the microbiome affect bile acid pool size and composition. With advancing liver disease and cirrhosis, there is dysbiosis in the fecal, ileal, and colonic mucosa, in addition to a decrease in bile acid concentration in the intestine due to the liver problems. This results in a dramatic shift toward the Firmicutes, particularly Clostridium cluster XIVa, and increasing production of deoxycholic acid. Alcohol intake speeds up these processes in the subjects with and without cirrhosis without significant FXR feedback. Taken together, these pathways can impact intestinal and systemic inflammation while worsening dysbiosis. The interaction between bile acids, alcohol, cirrhosis, and dysbiosis is an important relationship that influences intestinal and systemic inflammation, which in turn determines progression of the overall disease process. These interactions and the impact of commonly used therapies for liver disease can provide

  2. Gut microbiota, cirrhosis and alcohol regulate bile acid metabolism in the gut

    PubMed Central

    Ridlon, Jason M.; Kang, Dae-Joong; Hylemon, Phillip B.; Bajaj, Jasmohan S

    2015-01-01

    The understanding of the complex role of the bile acid-gut microbiome axis in health and disease processes is evolving rapidly. Our focus revolves around the interaction of the gut microbiota with liver diseases, especially cirrhosis. The bile acid pool size has recently been shown to be a function of microbial metabolism of bile acid and regulation of the microbiota by bile acids is important in the development and progression of several liver diseases. Humans produce a large, conjugated hydrophilic bile acid pool, maintained through positive-feedback antagonism of FXR in intestine and liver. Microbes use bile acids, and via FXR signaling this results in a smaller, unconjugated hydrophobic bile acid pool. This equilibrium is critical to maintain health. The challenge is to examine the manifold functions of gut bile acids as modulators of antibiotic, probiotic and disease progression in cirrhosis, metabolic syndrome and alcohol use. Recent studies have shown potential mechanisms explaining how perturbations in the microbiome affect bile acid pool size and composition. With advancing liver disease and cirrhosis, there is dysbiosis in the fecal, ileal and colonic mucosa, in addition to a decrease in bile acid concentration in the intestine due to the liver problems. This results in a dramatic shift toward the Firmicutes, particularly Clostridium cluster XIVa and increasing production of deoxycholic acid (DCA). Alcohol intake speeds up these processes in the subjects with and without cirrhosis without significant FXR feedback. Taken together, these pathways can impact intestinal and systemic inflammation while worsening dysbiosis. The interaction between bile acids, alcohol, cirrhosis and dysbiosis is an important relationship that influences intestinal and systemic inflammation, which in turn determines progression of the overall disease process. These interactions and the impact of commonly used therapies for liver disease can provide insight into the pathogenesis

  3. Biotransformation of bile acids by clostridia.

    PubMed

    Owen, R W

    1985-10-01

    The metabolism of bile acids by nuclear dehydrogenating clostridia (NDC) was studied. NDC were able to desaturate the A-ring of 5 beta-cholan-3-oxo-24-oic acid, 12 alpha-hydroxy-5 beta-cholan-3-oxo-24-oic acid, 7 alpha-hydroxy-5 beta-cholan-3-oxo-24-oic acid, 6 alpha-hydroxy-5 beta-cholan-3-oxo-24-oic acid, 7 alpha, 12 alpha-dihydroxy-5 beta-cholan-3-oxo-24-oic acid, 3,12-dioxo-5 beta-cholan-24-oic acid but not 3,6-dioxo-5 beta-cholan-24-oic acid, 3,7-dioxo-5 beta-cholan-24-oic acid and 3,7,12-trioxo-5 beta-cholan-24-oic acid. In each case the sole product possessed a 4-ene-3-one structure. Desaturation of bile acids was more efficient than that of androstanes. NDC are, therefore, capable of introducing double bonds into the nucleus of bile acids as well as that of androstanes. The physiological significance of such reactions in relation to large bowel cancer has yet to be elucidated. PMID:2864454

  4. In vitro evidence that phosphatidylcholine protects against indomethacin/bile acid-induced injury to cells

    PubMed Central

    Dial, Elizabeth J.; Dawson, Paul A.

    2014-01-01

    Indomethacin is a powerful analgesic nonsteroidal anti-inflammatory drug (NSAID), but is limited in use by its primary side effect to cause gastrointestinal bleeding and serious injury. One factor important for exacerbating NSAID injury is the presence of bile acids, which may interact with indomethacin to form toxic mixed micelles in the gut. The development of a safer gastrointestinal formulation of indomethacin that is chemically complexed with phosphatidylcholine (PC-indomethacin) may offer an improved therapeutic agent, particularly in the presence of bile acid, but its potential protective mechanism is incompletely understood. Intestinal epithelial cells (IEC-6) were tested for injury with indomethacin (alone and plus various bile acids) compared with PC-indomethacin (alone and plus bile acids). To explore a role for bile acid uptake into cells as a requirement for NSAID injury, studies were performed using Madin-Darby canine kidney cells transfected with the apical sodium-dependent bile acid transporter (ASBT). Indomethacin, but not PC-indomethacin, was directly and dose-dependently injurious to IEC-6 cells. Similarly, the combination of any bile acid plus indomethacin, but not PC-indomethacin, induced cell injury. The expression of ASBT had a modest effect on the acute cytotoxicity of indomethacin in the presence of some conjugated bile acids. Complexing PC with indomethacin protected against the acute intestinal epithelial injury caused by indomethacin regardless of the presence of bile acids. The presence of luminal bile acid, but not its carrier-mediated uptake into the enterocyte, is required for acute indomethacin-induced cell injury. It is likely that initial cell damage induced by indomethacin occurs at or near the cell membrane, an effect exacerbated by bile acids and attenuated by PC. PMID:25477376

  5. 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

  6. [Evaluation on hepatotoxicity caused by Dioscorea bulbifera based on analysis of bile acids].

    PubMed

    Xu, Ying; Chen, Chong-Chong; Yang, Li; Wang, Jun-Ming; Ji, Li-Li; Wang, Zheng-Tao; Hu, Zhi-Bi

    2011-01-01

    Metabolic profile of bile acids was used to evaluate hepatotoxicity of mice caused by ethanol extraction of Dioscorea bulbifera L. (ethanol extraction, ET) and diosbulbin B (DB), separately. Ultra-performance liquid chromatography coupled with quadrupole mass spectrometry (UPLC-MS) was applied to determine the contents of all kinds of endogenous bile acids including free bile acids, taurine conjugates and glycine conjugates. Obvious liver injuries could be observed in mice after administrated with ET and DB. Based on the analysis using principle components analysis (PCA), toxic groups could be distinguished from their control groups, which suggested that the variance of the contents of bile acids could evaluate hepatotoxicity caused by ET and DB. Meanwhile, ET and DB toxic groups were classified in the same trends comparing to control groups in the loading plot, and difference between the two toxic groups could also be observed. DB proved to be one of the toxic components in Dioscorea bulbifera L. Bile acids of tauroursodeoxycholic acid (TUDCA), taurochenodeoxycholic acid (TCDCA), taurocholic acid (TCA), taurodeoxycholic acid (TDCA), cholic acid (CA) and others proved to be important corresponds to ET and DB induced liver injury according to analysis of partial least square-discriminant analysis (PLS-DA) and the statistical analysis showed that there were significant differences between the control groups and toxic groups (P < 0.01). Furthermore, good correlation could be revealed between the foregoing bile acids and ALT, AST. It indicated that taurine conjugated bile acids as TUDCA, TCDCA, TCA and TDCA along with CA could be considered as sensitive biomarkers of ET and DB induced liver injury. This work can provide the base for the further research on the evaluation and mechanism of hepatotoxicity caused by Dioscorea bulbifera L. PMID:21465807

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

    PubMed Central

    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. PMID:26208104

  8. 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. PMID:26208104

  9. 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. PMID:21691101

  10. Effects of ion substitution on bile acid-dependent and -independent bile formation by rat liver.

    PubMed Central

    Van Dyke, R W; Stephens, J E; Scharschmidt, B F

    1982-01-01

    To characterize the transport mechanisms responsible for formation of canalicular bile, we have examined the effects of ion substitution on bile acid-dependent and bile acid-independent bile formation by the isolated perfused rat liver. Complete replacement of perfusate sodium with choline and lithium abolished taurocholate-induced choleresis and reduced biliary taurocholate output by greater than 70%. Partial replacement of perfusate sodium (25 of 128 mM) by choline reduced bile acid-independent bile formation by 30% and replacement of the remaining sodium (103 mM) by choline reduced bile acid-independent bile formation by an additional 64%. In contrast, replacement of the remaining sodium (103 mM) by lithium reduced bile acid-independent bile formation by only an additional 20%, while complete replacement of sodium (128 mM) by lithium reduced bile formation by only 17%, and lithium replaced sodium as the predominant biliary cation. Replacement of perfusate bicarbonate by Tricine, a zwitterionic amino acid buffer, decreased bile acid-independent bile formation by greater than or equal to 50% and decreased biliary bicarbonate output by approximately 60%, regardless of the accompanying cation. In separate experiments, replacement of sodium by lithium essentially abolished Na,K-ATPase activity measured either as ouabain-suppressible ATP hydrolysis in rat liver or kidney homogenates, or as ouabain-suppressible 86Rb uptake by cultured rat hepatocytes. These studies indicate that bile acid(taurocholate)-dependent bile formation by rat liver exhibits a specific requirement for sodium, a finding probably attributable to the role(s) of sodium in hepatic sodium-coupled taurocholate uptake and/or in maintenance of Na,K-ATPase activity. The surprising finding that bile acid-independent bile formation was substantially unaltered by complete replacement of sodium with the permeant cation lithium does not appear to be explained by Na,K-ATPase-mediated lithium transport. Although

  11. Electrogenicity of Na(+)-coupled bile acid transporters.

    PubMed Central

    Weinman, S. A.

    1997-01-01

    The Na(+)-bile acid cotransporters NTCP and ASBT are largely responsible for the Na(+)-dependent bile acid uptake in hepatocytes and intestinal epithelial cells, respectively. This review discusses the experimental methods available for demonstrating electrogenicity and examines the accumulating evidence that coupled transport by each of these bile acid transporters is electrogenic. The evidence includes measurements of transport-associated currents by patch clamp electrophysiological techniques, as well as direct measurement of fluorescent bile acid transport rates in whole cell patch clamped, voltage clamped cells. The results support a Na+:bile acid coupling stoichiometry of 2:1. PMID:9626753

  12. Characterization of bile acids and fatty acids from ox bile in oil paintings by gas chromatography-mass spectrometry.

    PubMed

    Casas-Catalán, M J; Doménech-Carbó, M T; Mateo-Castro, R; Gimeno-Adelantado, J V; Bosch-Reig, F

    2004-02-01

    Characterization of ox bile, traditionally used in painting, is of interest in the fields of archaeometry and conservation and restoration of works of art. Bile acids, fatty acids (F), and cholesterol found in ox bile have been identified using a derivatization method that combines the formation of ethyl esters from the carboxylic groups and the trimethylsilyl ethers from hydroxyl groups. This method of analysis is consistent with these others proposed by the authors to analyze drying oils, proteins, and diterpenic resins usually used as binders and varnishes by the painters. Bile acids from binary samples such as animal glue/ox bile, casein/ox bile and Arabic gum/ox bile have been successfully analyzed using the proposed method. Finally, a method of analysis of mixtures of drying oil and ox bile has been also proposed attempting to quantitatively characterize samples in which ox bile was added to the drying oil for increasing the surfactant properties. PMID:14763811

  13. Se-75-labeled bile acid analogs, new radiopharmaceuticals for investigating the enterohepatic circulation. [Rats

    SciTech Connect

    Boyd, G.S.; Merrick, M.V.; Monks, R.; Thomas, I.L.

    1981-08-01

    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 the 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.

  14. Bile acids: Chemistry, physiology, and pathophysiology

    PubMed Central

    Monte, Maria J; Marin, Jose JG; Antelo, Alvaro; Vazquez-Tato, Jose

    2009-01-01

    The family of bile acids includes a group of molecular species of acidic steroids with very peculiar physical-chemical and biological characteristics. They are synthesized by the liver from cholesterol through several complementary pathways that are controlled by mechanisms involving fine-tuning by the levels of certain bile acid species. Although their best-known role is their participation in the digestion and absorption of fat, they also play an important role in several other physiological processes. Thus, genetic abnormalities accounting for alterations in their synthesis, biotransformation and/or transport may result in severe alterations, even leading to lethal situations for which the sole therapeutic option may be liver transplantation. Moreover, the increased levels of bile acids reached during cholestatic liver diseases are known to induce oxidative stress and apoptosis, resulting in damage to the liver parenchyma and, eventually, extrahepatic tissues. When this occurs during pregnancy, the outcome of gestation may be challenged. In contrast, the physical-chemical and biological properties of these compounds have been used as the bases for the development of drugs and as pharmaceutical tools for the delivery of active agents. PMID:19230041

  15. 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

  16. 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.

  17. 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

  18. 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. PMID:24421907

  19. Advances in understanding of bile acid diarrhea

    PubMed Central

    Camilleri, Michael

    2014-01-01

    Bile acids (BA) are actively reabsorbed in the terminal ileum by the apical Na+-dependent bile salt transporter. This review addresses the epidemiology, pathophysiology, diagnosis and treatment of BA diarrhea (BAD). BAD is typically caused by ileal resection or disease; 25–33% of patients with chronic functional diarrhea or irritable bowel syndrome-diarrhea (IBS-D) have BAD, possibly from deficiency in the ileal hormone, FGF-19, which normally provides feedback inhibition of BA synthesis. Diagnosis of BAD is typically based on reduced BA retention of radiolabeled BA (75SeHCAT), increased BA synthesis (serum C4) or increased fecal BA loss. In clinical practice, diagnosis is often based on response to BA sequestrants (e.g., cholestyramine or colesevelam). Diagnostic tests for BA malabsorption (BAM) need to be used more extensively in clinical practice. In the future, farnesoid X receptor agonists that stimulate ileal production of FGF-19 may be alternative treatments of BAD. PMID:24410472

  20. Advances in understanding of bile acid diarrhea.

    PubMed

    Camilleri, Michael

    2014-01-01

    Bile acids (BA) are actively reabsorbed in the terminal ileum by the apical Na(+)-dependent bile salt transporter. This review addresses the epidemiology, pathophysiology, diagnosis and treatment of BA diarrhea (BAD). BAD is typically caused by ileal resection or disease; 25-33% of patients with chronic functional diarrhea or irritable bowel syndrome-diarrhea (IBS-D) have BAD, possibly from deficiency in the ileal hormone, FGF-19, which normally provides feedback inhibition of BA synthesis. Diagnosis of BAD is typically based on reduced BA retention of radiolabeled BA ((75)SeHCAT), increased BA synthesis (serum C4) or increased fecal BA loss. In clinical practice, diagnosis is often based on response to BA sequestrants (e.g., cholestyramine or colesevelam). Diagnostic tests for BA malabsorption (BAM) need to be used more extensively in clinical practice. In the future, farnesoid X receptor agonists that stimulate ileal production of FGF-19 may be alternative treatments of BAD. PMID:24410472

  1. Protective effect of bile acid derivatives in phalloidin-induced rat liver toxicity.

    PubMed

    Herraez, Elisa; Macias, Rocio I R; Vazquez-Tato, Jose; Hierro, Carlos; Monte, Maria J; Marin, Jose J G

    2009-08-15

    Phalloidin causes severe liver damage characterized by marked cholestasis, which is due in part to irreversible polymerization of actin filaments. Liver uptake of this toxin through the transporter OATP1B1 is inhibited by the bile acid derivative BALU-1, which does not inhibit the sodium-dependent bile acid transporter NTCP. The aim of the present study was to investigate whether BALU-1 prevents liver uptake of phalloidin without impairing endogenous bile acid handling and hence may have protective effects against the hepatotoxicity induced by this toxin. In anaesthetized rats, i.v. administration of BALU-1 increased bile flow more than taurocholic acid (TCA). Phalloidin administration decreased basal (-60%) and TCA-stimulated bile flow (-55%) without impairing bile acid output. Phalloidin-induced cholestasis was accompanied by liver necrosis, nephrotoxicity and haematuria. In BALU-1-treated animals, phalloidin-induced cholestasis was partially prevented. Moreover haematuria was not observed, which was consistent with histological evidences of BALU-1-prevented injury of liver and kidney tissue. HPLC-MS/MS analysis revealed that BALU-1 was secreted in bile mainly in non-conjugated form, although a small proportion (<5%) of tauro-BALU-1 was detected. BALU-1 did not inhibit the biliary secretion of endogenous bile acids. When highly choleretic bile acids, - ursodeoxycholic (UDCA) and dehydrocholic acid (DHCA) - were administered, they were found less efficient than BALU-1 in preventing phalloidin-induced cholestasis. Biliary phalloidin elimination was low but it was increased by BALU-1>TCA>DHCA>UDCA. In conclusion, BALU-1 is able to protect against phalloidin-induced hepatotoxicity, probably due to an inhibition of the liver uptake and an enhanced biliary secretion of this toxin. PMID:19409403

  2. Protective effect of bile acid derivatives in phalloidin-induced rat liver toxicity

    SciTech Connect

    Herraez, Elisa; Macias, Rocio I.R.; Vazquez-Tato, Jose; Hierro, Carlos; Monte, Maria J.; Marin, Jose J.G.

    2009-08-15

    Phalloidin causes severe liver damage characterized by marked cholestasis, which is due in part to irreversible polymerization of actin filaments. Liver uptake of this toxin through the transporter OATP1B1 is inhibited by the bile acid derivative BALU-1, which does not inhibit the sodium-dependent bile acid transporter NTCP. The aim of the present study was to investigate whether BALU-1 prevents liver uptake of phalloidin without impairing endogenous bile acid handling and hence may have protective effects against the hepatotoxicity induced by this toxin. In anaesthetized rats, i.v. administration of BALU-1 increased bile flow more than taurocholic acid (TCA). Phalloidin administration decreased basal (- 60%) and TCA-stimulated bile flow (- 55%) without impairing bile acid output. Phalloidin-induced cholestasis was accompanied by liver necrosis, nephrotoxicity and haematuria. In BALU-1-treated animals, phalloidin-induced cholestasis was partially prevented. Moreover haematuria was not observed, which was consistent with histological evidences of BALU-1-prevented injury of liver and kidney tissue. HPLC-MS/MS analysis revealed that BALU-1 was secreted in bile mainly in non-conjugated form, although a small proportion (< 5%) of tauro-BALU-1 was detected. BALU-1 did not inhibit the biliary secretion of endogenous bile acids. When highly choleretic bile acids, - ursodeoxycholic (UDCA) and dehydrocholic acid (DHCA) - were administered, they were found less efficient than BALU-1 in preventing phalloidin-induced cholestasis. Biliary phalloidin elimination was low but it was increased by BALU-1 > TCA > DHCA > UDCA. In conclusion, BALU-1 is able to protect against phalloidin-induced hepatotoxicity, probably due to an inhibition of the liver uptake and an enhanced biliary secretion of this toxin.

  3. Bile salts of the West Indian manatee, Trichechus manatus latirostris: novel bile alcohol sulfates and absence of bile acids.

    PubMed

    Kuroki, S; Schteingart, C D; Hagey, L R; Cohen, B I; Mosbach, E H; Rossi, S S; Hofmann, A F; Matoba, N; Une, M; Hoshita, T

    1988-04-01

    The bile salts present in gallbladder bile of the West Indian manatee, Trichechus manatus latirostris, an herbivorous marine mammal of the tropical and subtropical margins of the Atlantic Ocean, were found to consist of a mixture of bile alcohol sulfates. Bile acids, previously believed to be present in all mammals, were not detected. Using chromatography, mass spectrometry, and 1H- and 13C-nuclear magnetic resonance spectroscopy, the major bile alcohol was identified as 5 beta-cholestane-3 alpha,6 beta,7 alpha-25,26-pentol; that is, it had the nuclear structure of alpha-muricholic acid and the side chain structure of bufol. This compound has not been described previously and the trivial name "alpha-trichechol" is proposed. The second most abundant compound was 5 beta-cholestane-3 alpha,7 alpha,25,26-tetrol. Other bile alcohols were tentatively identified as 5 beta-cholestane-3 alpha,6 beta,7 beta,25,26-pentol (named beta-trichechol), 3 alpha,6 alpha,7 beta, 25-26-pentol (named omega-trichechol) and 5 beta-cholestane-3 alpha,6 beta,7 alpha,26-tetrol. The 1H and 13C NMR spectra of the four 6,7 epimers of 3,6,7 trihydroxy bile acids are described and discussed. All bile alcohols were present as ester sulfates, the sulfate group being tentatively assigned to the 26-hydroxy group. 12-Hydroxy compounds were not detected. The manatee is the first mammal found to lack bile acids, presumably because it lacks the enzymes required for oxidation of the 26-hydroxy group to a carboxylic acid. Trichechols, like other bile salts, are water-soluble end products of cholesterol metabolism; whether they also function as biological surfactants in promoting biliary cholesterol secretion or lipid digestion is unknown. PMID:3392467

  4. Kinetic analysis of bile acid sulfation by stably expressed human sulfotransferase 2A1 (SULT2A1).

    PubMed

    Huang, J; Bathena, S P; Tong, J; Roth, M; Hagenbuch, B; Alnouti, Y

    2010-03-01

    Human sulfotransferase 2A1 (SULT2A1) is a member of the hydroxysteroid sulfotransferase (SULT2) family that mediates sulfo-conjugation of a variety of endogenous molecules including dehydroepiandrosterone (DHEA) and bile acids. In this study, we have constructed a stable cell line expressing SULT2A1 by transfection into HEK293 cells. The expression system was used to characterize and compare the sulfation kinetics of DHEA and 15 human bile acids by SULT2A1. Formation of DHEA sulfate demonstrated Michaelis-Menten kinetics with apparent K(m) and V(max) values of 3.8 muM and 130.8 pmol min(-1) mg(-1) protein, respectively. Sulfation kinetics of bile acids also demonstrated Michaelis-Menten kinetics with a marked variation in apparent K(m) and V(max) values between individual bile acids. Sulfation affinity was inversely proportional to the number of hydroxyl groups of bile acids. The monohydroxy- and most toxic bile acid (lithocholic acid) had the highest affinity, whereas the trihydroxy- and least toxic bile acid (cholic acid) had the lowest affinity to sulfation by SULT2A1. Intrinsic clearance (CL(int)) of ursodeoxycholic acid (UDCA) was approximately 1.5- and 9.0-fold higher than that of deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA), respectively, despite the fact that all three are dihydroxy bile acids. PMID:20102295

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

    PubMed

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

    2016-09-01

    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

  6. Bile Acid diarrhea: prevalence, pathogenesis, and therapy.

    PubMed

    Camilleri, Michael

    2015-05-23

    Bile acid diarrhea (BAD) is usually seen in patients with ileal Crohn's disease or ileal resection. However, 25% to 50% of patients with functional diarrhea or diarrhea-predominant irritable bowel syndrome (IBS-D) also have evidence of BAD. It is estimated that 1% of the population may have BAD. The causes of BAD include a deficiency in fibroblast growth factor 19 (FGF-19), a hormone produced in enterocytes that regulates hepatic bile acid (BA) synthesis. Other potential causes include genetic variations that affect the proteins involved in BA enterohepatic circulation and synthesis or in the TGR5 receptor that mediates the actions of BA in colonic secretion and motility. BAs enhance mucosal permeability, induce water and electrolyte secretion, and accelerate colonic transit partly by stimulating propulsive high-amplitude colonic contractions. There is an increased proportion of primary BAs in the stool of patients with IBS-D, and some changes in the fecal microbiome have been described. There are several methods of diagnosing BAD, such as (75)selenium homotaurocholic acid test retention, serum C4, FGF-19, and fecal BA measurement; presently, therapeutic trials with BA sequestrants are most commonly used for diagnosis. Management involves the use of BA sequestrants including cholestyramine, colestipol, and colesevelam. FXR agonists such as obeticholic acid constitute a promising new approach to treating BAD. PMID:25918262

  7. Bile Acid Diarrhea: Prevalence, Pathogenesis, and Therapy

    PubMed Central

    Camilleri, Michael

    2015-01-01

    Bile acid diarrhea (BAD) is usually seen in patients with ileal Crohn’s disease or ileal resection. However, 25% to 50% of patients with functional diarrhea or diarrhea-predominant irritable bowel syndrome (IBS-D) also have evidence of BAD. It is estimated that 1% of the population may have BAD. The causes of BAD include a deficiency in fibroblast growth factor 19 (FGF-19), a hormone produced in enterocytes that regulates hepatic bile acid (BA) synthesis. Other potential causes include genetic variations that affect the proteins involved in BA enterohepatic circulation and synthesis or in the TGR5 receptor that mediates the actions of BA in colonic secretion and motility. BAs enhance mucosal permeability, induce water and electrolyte secretion, and accelerate colonic transit partly by stimulating propulsive high-amplitude colonic contractions. There is an increased proportion of primary BAs in the stool of patients with IBS-D, and some changes in the fecal microbiome have been described. There are several methods of diagnosing BAD, such as 75selenium homotaurocholic acid test retention, serum C4, FGF-19, and fecal BA measurement; presently, therapeutic trials with BA sequestrants are most commonly used for diagnosis. Management involves the use of BA sequestrants including cholestyramine, colestipol, and colesevelam. FXR agonists such as obeticholic acid constitute a promising new approach to treating BAD. PMID:25918262

  8. [The physiology and pathology of bile acid metabolism].

    PubMed

    Coraggio, F; Farro, M; Spina, M

    1980-01-01

    The biochemistry and metabolism of bile acids are briefly described together with their importance in the maintenance of biliary homeostasis. An account is given os some situations in which such metabolism is impaired: in cirrhosis of the liver, an isotope technique was used to show a fall in cholic acid (expression of liver cell damage); in cholostasis, stress is laid on reduced bile acid synthesis and a simultaneous increase in sensitivity of the bile canicular epithelium to secretin stimulation. Lastly, evidence is produced to suggest that the diarrhoea which often recurs after extensive intestinal resection is secondary to an increase in intestinal AMPc cells induced by bile acids. PMID:6257207

  9. 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

  10. Effects of feeding bile acids and a bile acid sequestrant on hepatic bile acid composition in mice.

    PubMed

    Zhang, Youcai; Klaassen, Curtis D

    2010-11-01

    An improved ultra performance liquid chromatography-tandem mass spectrometry (UPLC/MS/MS) method was established for the simultaneous analysis of various bile acids (BA) and applied to investigate liver BA content in C57BL/6 mice fed 1% cholic acid (CA), 0.3% deoxycholic acid (DCA), 0.3% chenodeoxycholic acid (CDCA), 0.3% lithocholic acid (LCA), 3% ursodeoxycholic acid (UDCA), or 2% cholestyramine (resin). Results indicate that mice have a remarkable ability to maintain liver BA concentrations. The BA profiles in mouse livers were similar between CA and DCA feedings, as well as between CDCA and LCA feedings. The mRNA expression of Cytochrome P450 7a1 (Cyp7a1) was suppressed by all BA feedings, whereas Cyp7b1 was suppressed only by CA and UDCA feedings. Gender differences in liver BA composition were observed after feeding CA, DCA, CDCA, and LCA, but they were not prominent after feeding UDCA. Sulfation of CA and CDCA was found at the 7-OH position, and it was increased by feeding CA or CDCA more in male than female mice. In contrast, sulfation of LCA and taurolithocholic acid (TLCA) was female-predominant, and it was increased by feeding UDCA and LCA. In summary, the present systematic study on BA metabolism in mice will aid in interpreting BA-mediated gene regulation and hepatotoxicity. PMID:20671298

  11. Effects of feeding bile acids and a bile acid sequestrant on hepatic bile acid composition in mice[S

    PubMed Central

    Zhang, Youcai; Klaassen, Curtis D.

    2010-01-01

    An improved ultra performance liquid chromatography-tandem mass spectrometry (UPLC/MS/MS) method was established for the simultaneous analysis of various bile acids (BA) and applied to investigate liver BA content in C57BL/6 mice fed 1% cholic acid (CA), 0.3% deoxycholic acid (DCA), 0.3% chenodeoxycholic acid (CDCA), 0.3% lithocholic acid (LCA), 3% ursodeoxycholic acid (UDCA), or 2% cholestyramine (resin). Results indicate that mice have a remarkable ability to maintain liver BA concentrations. The BA profiles in mouse livers were similar between CA and DCA feedings, as well as between CDCA and LCA feedings. The mRNA expression of Cytochrome P450 7a1 (Cyp7a1) was suppressed by all BA feedings, whereas Cyp7b1 was suppressed only by CA and UDCA feedings. Gender differences in liver BA composition were observed after feeding CA, DCA, CDCA, and LCA, but they were not prominent after feeding UDCA. Sulfation of CA and CDCA was found at the 7-OH position, and it was increased by feeding CA or CDCA more in male than female mice. In contrast, sulfation of LCA and taurolithocholic acid (TLCA) was female-predominant, and it was increased by feeding UDCA and LCA. In summary, the present systematic study on BA metabolism in mice will aid in interpreting BA-mediated gene regulation and hepatotoxicity. PMID:20671298

  12. Isolation and characterization of a Lactobacillus amylovorus mutant depleted in conjugated bile salt hydrolase activity: relation between activity and bile salt resistance.

    PubMed

    Grill, J P; Cayuela, C; Antoine, J M; Schneider, F

    2000-10-01

    Growth experiments were conducted on Lactobacillus amylovorus DN-112 053 in batch culture, with or without pH regulation. Conjugated bile salt hydrolase (CBSH) activity was examined as a function of culture growth. The CBSH activity increased during growth but its course depended on bile salts type and culture conditions. A Lact. amylovorus mutant was isolated from the wild-type strain of Lact. amylovorus DN-112 053 after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. An agar plate assay was used to detect mutants without CBSH activity. In resting cell experiments, the strain showed reduced activity. Differences between growth parameters determined for wild-type and mutant strains were not detected. Comparative native gel electrophoresis followed by CBSH activity staining demonstrated the loss of proteins harbouring this activity in the mutant. Four protein bands corresponding to CBSH were observed in the wild-type strain but only one was detected in the mutant. The specific growth rate of the mutant strain was affected more by bile salts than the wild-type strain. Nevertheless, bile was more toxic for the wild-type strain. In viability studies in the presence of nutrients, it was demonstrated that glycodeoxycholic acid exerted a higher toxicity than taurodeoxycholic acid in a pH-dependent manner. No difference was apparent between the two strains. In the absence of nutrients, the wild-type strain died after 2 h whereas no effect was observed for the mutant. The de-energization experiments performed using the ionophores nigericin and valinomycin suggested that the chemical potential of protons (ZDeltapH) was involved in Lactobacillus bile salt resistance. PMID:11054157

  13. Effects of bile acid administration on bile acid synthesis and its circadian rhythm in man

    SciTech Connect

    Pooler, P.A.; Duane, W.C.

    1988-09-01

    In man bile acid synthesis has a distinct circadian rhythm but the relationship of this rhythm to feedback inhibition by bile acid is unknown. We measured bile acid synthesis as release of 14CO2 from (26-14C)cholesterol every 2 hr in three normal volunteers during five separate 24-hr periods. Data were fitted by computer to a cosine curve to estimate amplitude and acrophase of the circadian rhythm. In an additional six volunteers, we measured synthesis every 2 hr from 8:00 a.m. to 4:00 p.m. only. During the control period, amplitude (expressed as percentage of mean synthesis) averaged 52% and acrophase averaged 6:49 a.m. During administration of ursodeoxycholic acid (15 mg per kg per day), synthesis averaged 126% of baseline (p less than 0.1), amplitude averaged 43% and acrophase averaged 6:20 a.m. During administration of chenodeoxycholic acid (15 mg per kg per day), synthesis averaged 43% of baseline (p less than 0.001), amplitude averaged 53% and acrophase averaged 9:04 a.m. Addition of prednisone to this regimen of chenodeoxycholic acid to eliminate release of 14CO2 from corticosteroid hormone synthesis resulted in a mean amplitude of 62% and a mean acrophase of 6:50 a.m., values very similar to those in the baseline period. Administration of prednisone alone also did not significantly alter the baseline amplitude (40%) or acrophase (6:28 a.m.). We conclude that neither chenodeoxycholic acid nor ursodeoxycholic acid significantly alters the circadian rhythm of bile acid synthesis in man.

  14. Comprehensive study of the biliary bile acid composition of patients with cystic fibrosis and associated liver disease before and after UDCA administration.

    PubMed

    Nakagawa, M; Colombo, C; Setchell, K D

    1990-08-01

    The biliary bile acid composition was determined for patients with cystic fibrosis and associated liver disease before and after the administration of ursodeoxycholic acid (10 to 15 mg/kg body wt/day). Bile acids were analyzed by fast atom bombardment ionization-mass spectrometry, high performance liquid chromatography and gas chromatography-mass spectrometry after individual bile acids were separated according to their mode of conjugation using the lipophilic anion exchanger, diethylaminohydroxypropyl Sephadex LH-20. More than 50 individual bile acids were identified in the bile of cystic fibrosis patients and these acids were predominantly secreted as glycine and taurine conjugates. Small proportions (less than 8% of the total) of unconjugated and sulfate conjugates were present. Of interest was the identification of two side-chain-elongated (C25) bile acids, homocholic and homochenodeoxycholic acids. After ursodeoxycholic acid was administered, duodenal bile became enriched with the conjugated species of ursodeoxycholic acid (accounting for 11.9% to 32.5% of the total biliary bile acids), but to a lesser extent than reported previously for patients with other liver diseases or gallstones who received comparable doses of ursodeoxycholic acid, and this presumably occurs because of bile acid malabsorption that is a feature of cystic fibrosis. The mean glycine/taurine ratio increased from 2.4 before ursodeoxycholic acid administration to 5 after ursodeoxycholic acid administration even though these patients also received taurine. Despite the relatively low enrichment of the bile by ursodeoxycholic acid, biochemical indices of liver function all improved in these patients after ursodeoxycholic acid administration. PMID:2391071

  15. 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

  16. Effects of bile acids on hepatocellular signaling and secretion.

    PubMed Central

    Beuers, U.

    1997-01-01

    Bile acids modulate hepatocellular signaling pathways in vitro at physiological concentrations. The present paper provides a brief overview of the effects of bile acids on three key messengers in liver cells: cytosolic free calcium, protein kinase A and protein kinase C. PMID:9626754

  17. Deficiency of Capicua disrupts bile acid homeostasis

    PubMed Central

    Kim, Eunjeong; Park, Sungjun; Choi, Nahyun; Lee, Jieon; Yoe, Jeehyun; Kim, Soeun; Jung, Hoe-Yune; Kim, Kyong-Tai; Kang, Hyojin; Fryer, John D.; Zoghbi, Huda Y.; Hwang, Daehee; Lee, Yoontae

    2015-01-01

    Capicua (CIC) has been implicated in pathogenesis of spinocerebellar ataxia type 1 and cancer in mammals; however, the in vivo physiological functions of CIC remain largely unknown. Here we show that Cic hypomorphic (Cic-L-/-) mice have impaired bile acid (BA) homeostasis associated with induction of proinflammatory cytokines. We discovered that several drug metabolism and BA transporter genes were down-regulated in Cic-L-/- liver, and that BA was increased in the liver and serum whereas bile was decreased within the gallbladder of Cic-L-/- mice. We also found that levels of proinflammatory cytokine genes were up-regulated in Cic-L-/- liver. Consistent with this finding, levels of hepatic transcriptional regulators, such as hepatic nuclear factor 1 alpha (HNF1α), CCAAT/enhancer-binding protein beta (C/EBPβ), forkhead box protein A2 (FOXA2), and retinoid X receptor alpha (RXRα), were markedly decreased in Cic-L-/- mice. Moreover, induction of tumor necrosis factor alpha (Tnfα) expression and decrease in the levels of FOXA2, C/EBPβ, and RXRα were found in Cic-L-/- liver before BA was accumulated, suggesting that inflammation might be the cause for the cholestasis in Cic-L-/- mice. Our findings indicate that CIC is a critical regulator of BA homeostasis, and that its dysfunction might be associated with chronic liver disease and metabolic disorders. PMID:25653040

  18. Intestinal interaction of bile acids, phospholipids, dietary fibers, and cholestyramine.

    PubMed

    Gallaher, D; Schneeman, B O

    1986-04-01

    Binding of bile acids and phospholipids to a number of dietary fibers and cholestyramine (CH) within the small intestine was determined. The fibers used were cellulose, wheat bran, oat bran, guar gum (GG), and lignin (LG). GG, LG, and CH bound significant quantities of bile acids. However, only the CH reduced the bile acid concentration within the aqueous phase of the intestinal contents. Significant phospholipid binding was found only with CH. None of the test substances significantly reduced the quantity of solubilized lipid. Multiple regression analysis indicated that the total quantity of bile acids and phospholipids in the aqueous phase of the intestinal contents was a significant predictor of the quantity of lipid solubilized within the contents (r2 = 0.67). The failure of GG and LG to significantly decrease the amount of solubilized lipid suggests that the hypocholesterolemic effect of these fibers is due more to their bile acid binding capacity than to an effect on lipid solubilization. PMID:3008573

  19. The cytotoxicity of hydrophobic bile acids is ameliorated by more hydrophilic bile acids in intestinal cell lines IEC-6 and Caco-2.

    PubMed

    Araki, Yoshio; Andoh, Akira; Bamba, Hiromichi; Yoshikawa, Kouhei; Doi, Hisakazu; Komai, Yasunobu; Higuchi, Akihiko; Fujiyama, Yoshihide

    2003-01-01

    Bile acids, especially those with hydrophobic properties, are known to possess cytotoxicity. However, the mechanisms responsible for the cytotoxicity of bile acids are still under investigation. On the other hand, the hydrophilic bile acid, ursodeoxycholic acid has been reported to exhibit therapeutic effects against cytotoxic hydrophobic bile acids. The aim of the present study was to investigate the cytotoxicity of individual bile acids and combinations of bile acids using the intestinal cell lines IEC-6 and Caco-2 cells. The cytotoxicities of individual bile acids and the effects of various bile acid combinations were evaluated using the MTS [3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay. The bile acids induced cytotoxic effects depending on their hydrophobicity except for hyodeoxycholic acid. In the study for the effects of combined bile acids, not only ursodeoxycholic acid but other hydrophilic bile salts such as cholic acid and hyocholic acid exhibited cytoprotection against deoxycholic acid-induced cytotoxicity. Moreover, even some hydrophobic bile acids, such as chenodeoxycholic acid also exhibited cytoprotection. It is possible that the cytotoxicity of hydrophobic bile acids is ameliorated by more hydrophilic bile acids under certain conditions. The understanding of the precise mechanism of this phenomenon remains to be determined. PMID:14534721

  20. Vitamin D receptor regulation of the steroid/bile acid sulfotransferase SULT2A1.

    PubMed

    Chatterjee, Bandana; Echchgadda, Ibtissam; Song, Chung Seog

    2005-01-01

    SULT2A1 is a sulfo-conjugating phase II enzyme expressed at very high levels in the liver and intestine, the two major first-pass metabolic tissues, and in the steroidogenic adrenal tissue. SULT2A1 acts preferentially on the hydroxysteroids dehydroepiandrosterone, testosterone/dihydrotestosterone, and pregnenolone and on cholesterol-derived amphipathic sterol bile acids. Several therapeutic drugs and other xenobiotics, which include xenoestrogens, are also sulfonated by this cytosolic steroid/bile acid sulfotransferase. Nonsteroid nuclear receptors with key roles in the metabolism and detoxification of endobiotics and xenobiotics, such as bile acid-activated farnesoid X receptor, xenobiotic-activated pregnane X receptor and constitutive androstane receptor, and lipid-activated peroxisome proliferator-activated receptor-alpha, mediate transcription induction of SULT2A1 in the enterohepatic system. The ligand-activated vitamin D receptor (VDR) is another nuclear receptor that stimulates SULT2A1 transcription, and the regulatory elements in human, mouse, and rat promoters directing this induction have been characterized. Given that bile acid sulfonation is catalyzed exclusively by SULT2A1 and that the 3alpha-sulfate of the highly toxic lithocholic acid is a major excretory metabolite in humans, we speculate that a role for the VDR pathway in SULT2A1 expression may have emerged to shield first-pass tissues from the cytotoxic effects of a bile acid overload arising from disrupted sterol homeostasis triggered by endogenous and exogenous factors. PMID:16399349

  1. BILE ACIDS REGULATE THE ONTOGENIC EXPRESSION OF ILEAL BILE ACID BINDING PROTEIN IN THE RAT VIA THE FARNESOID X RECEPTOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the rat, an increase in ileal bile acid binding protein (IBABP) expression occurs during the third postnatal week. In vitro studies suggest that bile acids (BAs) increase IBABP transcription by activating the BA receptor, farnesoid X receptor (FXR). Thus, we investigated the role of BAs on the on...

  2. Development of a bile acid-based newborn screen for Niemann-Pick disease type C.

    PubMed

    Jiang, Xuntian; Sidhu, Rohini; Mydock-McGrane, 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

    2016-05-01

    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, 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

  3. Mechanistic Modeling Reveals the Critical Knowledge Gaps in Bile Acid-Mediated DILI.

    PubMed

    Woodhead, J L; Yang, K; Brouwer, K L R; Siler, S Q; Stahl, S H; Ambroso, J L; Baker, D; Watkins, P B; Howell, B A

    2014-01-01

    Bile salt export pump (BSEP) inhibition has been proposed to be an important mechanism for drug-induced liver injury (DILI). Modeling can prioritize knowledge gaps concerning bile acid (BA) homeostasis and thus help guide experimentation. A submodel of BA homeostasis in rats and humans was constructed within DILIsym, a mechanistic model of DILI. In vivo experiments in rats with glibenclamide were conducted, and data from these experiments were used to validate the model. The behavior of DILIsym was analyzed in the presence of a simulated theoretical BSEP inhibitor. BSEP inhibition in humans is predicted to increase liver concentrations of conjugated chenodeoxycholic acid (CDCA) and sulfate-conjugated lithocholic acid (LCA) while the concentration of other liver BAs remains constant or decreases. On the basis of a sensitivity analysis, the most important unknowns are the level of BSEP expression, the amount of intestinal synthesis of LCA, and the magnitude of farnesoid-X nuclear receptor (FXR)-mediated regulation. PMID:25006780

  4. Decreased hepatotoxic bile acid composition and altered synthesis in progressive human nonalcoholic fatty liver disease

    SciTech Connect

    Lake, April D.; Novak, Petr; Shipkova, Petia; Aranibar, Nelly; Robertson, Donald; Reily, Michael D.; Lu, Zhenqiang; Lehman-McKeeman, Lois D.; Cherrington, Nathan J.

    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 BA 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

  5. Intestinal bile acid physiology and pathophysiology

    PubMed Central

    Martínez-Augustin, Olga; de Medina, Fermín Sánchez

    2008-01-01

    Bile acids (BAs) have a long established role in fat digestion in the intestine by acting as tensioactives, due to their amphipathic characteristics. BAs are reabsorbed very efficiently by the intestinal epithelium and recycled back to the liver via transport mechanisms that have been largely elucidated. The transport and synthesis of BAs are tightly regulated in part by specific plasma membrane receptors and nuclear receptors. In addition to their primary effect, BAs have been claimed to play a role in gastrointestinal cancer, intestinal inflammation and intestinal ionic transport. BAs are not equivalent in any of these biological activities, and structural requirements have been generally identified. In particular, some BAs may be useful for cancer chemoprevention and perhaps in inflammatory bowel disease, although further research is necessary in this field. This review covers the most recent developments in these aspects of BA intestinal biology. PMID:18837078

  6. Oleanolic acid alters bile acid metabolism and produces cholestatic liver injury in mice

    SciTech Connect

    Liu, Jie; Lu, Yuan-Fu; Zhang, Youcai; Wu, Kai Connie; Fan, Fang; Klaassen, Curtis D.

    2013-11-01

    Oleanolic acid (OA) is a triterpenoids that exists widely in plants. OA is effective in protecting against hepatotoxicants. Whereas a low dose of OA is hepatoprotective, higher doses and longer-term use of OA produce liver injury. This study characterized OA-induced liver injury in mice. Adult C57BL/6 mice were given OA at doses of 0, 22.5, 45, 90, and 135 mg/kg, s.c., daily for 5 days, and liver injury was observed at doses of 90 mg/kg and above, as evidenced by increases in serum activities of alanine aminotransferase and alkaline phosphatase, increases in serum total bilirubin, as well as by liver histopathology. OA-induced cholestatic liver injury was further evidenced by marked increases of both unconjugated and conjugated bile acids (BAs) in serum. Gene and protein expression analysis suggested that livers of OA-treated mice had adaptive responses to prevent BA accumulation by suppressing BA biosynthetic enzyme genes (Cyp7a1, 8b1, 27a1, and 7b1); lowering BA uptake transporters (Ntcp and Oatp1b2); and increasing a BA efflux transporter (Ostβ). OA increased the expression of Nrf2 and its target gene, Nqo1, but decreased the expression of AhR, CAR and PPARα along with their target genes, Cyp1a2, Cyp2b10 and Cyp4a10. OA had minimal effects on PXR and Cyp3a11. Taken together, the present study characterized OA-induced liver injury, which is associated with altered BA homeostasis, and alerts its toxicity potential. - Highlights: • Oleanolic acid at higher doses and long-term use may produce liver injury. • Oleanolic acid increased serum ALT, ALP, bilirubin and bile acid concentrations. • OA produced feathery degeneration, inflammation and cell death in the liver. • OA altered bile acid homeostasis, affecting bile acid synthesis and transport.

  7. Bile acid sulfotransferase I from rat liver sulfates bile acids and 3-hydroxy steroids: purification, N-terminal amino acid sequence, and kinetic properties.

    PubMed

    Barnes, S; Buchina, E S; King, R J; McBurnett, T; Taylor, K B

    1989-04-01

    A bile acid:3'phosphoadenosine-5'phosphosulfate:sulfotransferase (BAST I) from adult female rat liver cytosol has been purified 157-fold by a two-step isolation procedure. The N-terminal amino acid sequence of the 30,000 subunit has been determined for the first 35 residues. The Vmax of purified BAST I is 18.7 nmol/min per mg protein with N-(3-hydroxy-5 beta-cholanoyl)glycine (glycolithocholic acid) as substrate, comparable to that of the corresponding purified human BAST (Chen, L-J., and I. H. Segel, 1985. Arch. Biochem. Biophys. 241: 371-379). BAST I activity has a broad pH optimum from 5.5-7.5. Although maximum activity occurs with 5 mM MgCl2, Mg2+ is not essential for BAST I activity. The greatest sulfotransferase activity and the highest substrate affinity is observed with bile acids or steroids that have a steroid nucleus containing a 3 beta-hydroxy group and a 5-6 double bond or a trans A-B ring junction. These substrates have normal hyperbolic initial velocity curves with substrate inhibition occurring above 5 microM. Of the saturated 5 beta-bile acids, those with a single 3-hydroxy group are the most active. The addition of a second hydroxy group at the 6- or 7-position eliminates more than 99% of the activity. In contrast, 3 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oic acid (deoxycholic acid) is an excellent substrate. The initial velocity curves for glycolithocholic and deoxycholic acid conjugates are sigmoidal rather than hyperbolic, suggestive of an allosteric effect. Maximum activity is observed at 80 microM for glycolithocholic acid. All substrates, bile acids and steroids, are inhibited by the 5 beta-bile acid, 3-keto-5 beta-cholanoic acid. The data suggest that BAST I is the same protein as hydrosteroid sulfotransferase 2 (Marcus, C. J., et al. 1980. Anal. Biochem. 107: 296-304). PMID:2754334

  8. [Studies on pruritus in obstructive jaundice cases with special references to serum bile acid fractions].

    PubMed

    Mashima, H

    1991-08-01

    About, 22 cases with pruritus and 18 cases without pruritus of obstructive jaundice, serum bile acids were analysed quantitatively by high performance liquid chromatography (HPLC) before and after biliary decompression for the study on the relationship between pruritus and non-pruritus group. Analysis was also carried out on 11 cases with normal liver function as the control group. And 15 kinds of bile acids were as followed: unconjugates (ursodeoxycholic: UDCA, cholic: CA, chenodeoxycholic: CDCA, deoxycholic: DCA, lithocholic acid: LCA), glycine conjugates (Gly-UDCA, Gly-CA, Gly-CDCA, Gly-DCA, Gly-LCA) and taurine conjugates (Tau-UDCA, Tau-CA, Tau-CDCA, Tau-DCA, Tau-LCA). Data was analysed by t-test statistically. [I] Before biliary decompression (1) No significant difference was observed between the pruritus group and non-pruritus group about total bile acid level, total unconjugates level and CA/CDCA ratio. (2) On total glycine-conjugates level the pruritus group was significantly lower than the non-pruritus group, that level was about 3/5. Similarly on Gly-CA level was about 2/3, on Gly-CDCA level was about 1/2. (3) By contraries on total taurine-conjugates level the pruritus group was significantly high as compared with the non-pruritus group, that level was about two times. Similarly on Tau-CA and Tau-CDCA levels were about two times. (4) From there results on glycine/taurine ratio (G/T) of total bile acids pruritus group was significantly low as compared with the non-pruritus group, that level was about 1/3. Similarly on G/T ratio of CA level was about 2/5 and on G/T ratio of CDCA was about 1/3. (5) As for various unconjugates, UDCA level was significantly high in pruritus group as compared with non-pruritus group. [II] After biliary decompression No significant difference was shown in the composition of serum bile acids between the pruritus group and the non-pruritus group. These studies showed that the pruritus in the obstructive jaundice cases stood in a

  9. Serum Bile Acids in Repaired Tetralogy of Fallot: A Marker for Liver and Heart?

    PubMed Central

    Köstenberger, Martin; Jud, Alexandra; Fauler, Günter; Scharnagl, Hubert; Stojakovic, Tatjana; Marterer, Robert; Gamillscheg, Andreas; Jahnel, Jörg

    2015-01-01

    Background and Aims Patients with repaired tetralogy of Fallot may develop chronic right ventricular dysfunction and hepatic congestion over time. We hypothesized that bile acid metabolism is altered in repaired tetralogy of Fallot patients and therefore sought to correlate right ventricular indices with serum bile acid levels. Methods Indexed right ventricular end diastolic volume, as assessed by cardiac magnetic-resonance imaging, was classified as <100ml/m2 (Group 1, n = 5), 100–150ml/m2 (Group 2, n = 18), and >150ml/m2 (Group 3, n = 6) in 29 patients with repaired tetralogy of Fallot. Pulmonary regurgitation fraction and right ventricular ejection fraction were calculated. The serum bile acid profile, including 15 species, in these patients was determined by liquid chromatography coupled with mass spectrometry. Results Serum bile acid levels increased from Group 1 to Group 3 (2.5 ± 0.7; 4.1 ± 2.5; 6.0 ± 2.8 μmol/l, respectively) with significantly increased bile acid values in Group 3 compared to Group 1 (p≤0.05). In Group 3, but not in Group 1 and 2, a significant increase in glycine-conjugated bile acids was observed. Pulmonary regurgitation fraction increased (12 ± 1; 28 ± 16; 43 ± 3%, Groups 1–3, respectively) and right ventricular ejection fraction decreased (48.4 ± 6.4; 48.5 ± 6.5; 42.1 ± 5.3%, Groups 1–3, respectively) with rising indexed right ventricular end diastolic volume. Conclusions These preliminary results suggest that serum bile acid levels are positively correlated with indexed right ventricular end-diastolic volume in patients with repaired tetralogy of Fallot; however, this needs to be confirmed in a larger patient cohort. PMID:26659834

  10. Heterogeneity of bile pigment conjugates as revealed by chromatography of their anthranilate azopigments

    PubMed Central

    Heirwegh, K. P. M.; Van Hees, G. P.; Leroy, P.; Van Roy, F. P.; Jansen, F. H.

    1970-01-01

    1. Azopigments derived from conjugated bile pigments by coupling with the diazonium salt of ethyl anthranilate are analysed conveniently by quantitative t.l.c. or by column chromatography on CM-cellulose. 2. By chromatographic studies combined with a series of chemical tests six groups of azopigments were demonstrable in preparations from bile and from icteric urine of man. Azobilirubin and its β-d-monoglucuronide have hitherto been considered to be the only major derivatives that can be obtained from human bile pigments. In the present work, other azopigments accounted for 30–40% of the total azopigment material, and the amounts of these showed considerable variation among biological fluids. 3. The divergence of the present results from earlier work is probably related to the use of milder diazotization conditions and of chromatographic techniques with a high resolving power. 4. The thin-layer chromatographic systems developed allow rapid and quantitative analysis of azopigments derived from bile pigments. PMID:5500353

  11. Bile Acid Synthesis in the Isolated, Perfused Rabbit Liver

    PubMed Central

    Mosbach, E. H.; Rothschild, M. A.; Bekersky, I.; Oratz, M.; Mongelli, J.

    1971-01-01

    These experiments were carried out to demonstrate the usefulness of the perfused rabbit liver for studies of bile acid metabolism, and to determine the rate-limiting enzyme of bile acid synthesis. Rabbits were fed a semisynthetic diet, with or without the addition of 1% cholestyramine, under controlled conditions. At the end of 2-5 wk, the livers were removed and perfused for 2.5 hr employing various 14C-labeled precursors to measure de novo cholic acid synthesis. The livers were then analyzed for cholesterol, and the bile collected during the perfusion was analyzed for cholesterol and bile acids. Control bile contained, on the average, 0.34 mg of glycocholate, 7.4 mg of glycodeoxycholate, and 0.06 mg of cholesterol. After cholestyramine treatment of the donor rabbits, the bile contained 3.3 mg of glycocholate, 3.7 mg of glycodeoxycholate, and 0.05 mg of cholesterol. It was assumed that in cholestyramine-treated animals the enterohepatic circulation of the bile acids had been interrupted sufficiently to release the feedback inhibition of the rate-controlling enzyme of bile acid synthesis. Therefore, a given precursor should be incorporated into bile acids at a more rapid rate in livers of cholestyramine-treated animals, provided that the precursor was acted upon by the rate-controlling enzyme. It was found that the incorporation of acetate-14C, mevalonolactone-14C, and cholesterol-14C into cholate was 5-20 times greater in the livers of cholestyramine-treated animals than in the controls. In contrast, there was no difference in the incorporation of 7α-hydroxycholesterol-14C into cholate regardless of dietary pretreatment. It was concluded that given an adequate precursor pool, the 7α-hydroxylation of cholesterol is the rate-limiting step in bile acid formation. PMID:5097576

  12. Bile acids: emerging role in management of liver diseases.

    PubMed

    Asgharpour, Amon; Kumar, Divya; Sanyal, Arun

    2015-10-01

    Bile acids are well known for their effects on cholesterol homeostasis and lipid digestion. Since the discovery of bile acid receptors, of which there are farnesoid X receptor (FXR), a nuclear receptor, and the plasma membrane G-protein receptor, as well as Takeda G-protein coupled receptor clone 5, further roles have been elucidated for bile acids including glucose and lipid metabolism as well as inflammation. Additionally, treatment with bile acid receptor agonists has shown a decrease in the amount of atherosclerosis plaque formation and decreased portal vascular resistance and portal hypotension in animal models. Furthermore, rodent models have demonstrated antifibrotic activity using bile acid receptor agonists. Early human data using a FXR agonist, obeticholic acid, have shown promising results with improvement of histological activity and even a reduction of fibrosis. Human studies are ongoing and will provide further information on bile acid receptor agonist therapies. Thus, bile acids and their derivatives have the potential for management of liver diseases and potentially other disease states including diabetes and the metabolic syndrome. PMID:26320013

  13. Bile acids: emerging role in management of liver diseases

    PubMed Central

    Asgharpour, Amon; Kumar, Divya

    2016-01-01

    Bile acids are well known for their effects on cholesterol homeostasis and lipid digestion. Since the discovery of bile acid receptors, of which there are farnesoid X receptor (FXR), a nuclear receptor, and the plasma membrane G-protein receptor, as well as Takeda G-protein coupled receptor clone 5, further roles have been elucidated for bile acids including glucose and lipid metabolism as well as inflammation. Additionally, treatment with bile acid receptor agonists has shown a decrease in the amount of atherosclerosis plaque formation and decreased portal vascular resistance and portal hypotension in animal models. Furthermore, rodent models have demonstrated antifibrotic activity using bile acid receptor agonists. Early human data using a FXR agonist, obeticholic acid, have shown promising results with improvement of histological activity and even a reduction of fibrosis. Human studies are ongoing and will provide further information on bile acid receptor agonist therapies. Thus, bile acids and their derivatives have the potential for management of liver diseases and potentially other disease states including diabetes and the metabolic syndrome. PMID:26320013

  14. 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. PMID:27377011

  15. Differentiated quantification of human bile acids in serum by high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Burkard, Ines; von Eckardstein, Arnold; Rentsch, Katharina M

    2005-11-01

    Determination of quantitative changes in the pattern of serum bile acids is important for the monitoring of diseases affecting bile acid metabolism. A sensitive and specific high-performance liquid chromatography (HPLC)-MS/MS method was developed for the differentiated quantification of unconjugated as well as glycine- and taurine-conjugated cholic, chenodeoxycholic (CDCA), deoxycholic (DCA), ursodeoxycholic (UDCA) and lithocholic acid (LCA) in serum samples. After solid-phase extraction and reversed-phase HPLC separation, detection of the conjugated bile acids was performed using electrospray ionization (ESI)-MS/MS and selected reaction monitoring mode, whereas unconjugated bile acids were determined by ESI-MS and selected ion monitoring mode. The within-day and between-day coefficients of variation were below 7% for all bile acids and the recovery rates of the extraction procedure were between 84.9 and 105%. The developed method was applied to a group of 21 healthy volunteers and preliminary reference intervals in serum were established. In patients with drug-induced cholestasis, an elevation of primary bile acids has been shown. PMID:16182619

  16. Bile Acid-Activated Receptors, Intestinal Microbiota, and the Treatment of Metabolic Disorders.

    PubMed

    Fiorucci, Stefano; Distrutti, Eleonora

    2015-11-01

    The composition of the bile acid pool is a function of the microbial metabolism of bile acids in the intestine. Perturbations of the microbiota shape the bile acid pool and modulate the activity of bile acid-activated receptors (BARs) even beyond the gastrointestinal tract, triggering various metabolic axes and altering host metabolism. Bile acids, in turn, can also regulate the composition of the gut microbiome at the highest taxonomic levels. Primary bile acids from the host are preferential ligands for the farnesoid X receptor (FXR), while secondary bile acids from the microbiota are ligands for G-protein-coupled bile acid receptor 1 (GPBAR1). In this review, we examine the role of bile acid signaling in the regulation of intestinal microbiota and how changes in bile acid composition affect human metabolism. Bile acids may offer novel therapeutic modalities in inflammation, obesity, and diabetes. PMID:26481828

  17. Hydrophobic bile acids, genomic instability, Darwinian selection, and colon carcinogenesis

    PubMed Central

    Payne, Claire M; Bernstein, Carol; Dvorak, Katerina; Bernstein, Harris

    2008-01-01

    Sporadic colon cancer is caused predominantly by dietary factors. We have selected bile acids as a focus of this review since high levels of hydrophobic bile acids accompany a Western-style diet, and play a key role in colon carcinogenesis. We describe how bile acid-induced stresses cause cell death in susceptible cells, contribute to genomic instability in surviving cells, impose Darwinian selection on survivors and enhance initiation and progression to colon cancer. The most likely major mechanisms by which hydrophobic bile acids induce stresses on cells (DNA damage, endoplasmic reticulum stress, mitochondrial damage) are described. Persistent exposure of colon epithelial cells to hydrophobic bile acids can result in the activation of pro-survival stress-response pathways, and the modulation of numerous genes/proteins associated with chromosome maintenance and mitosis. The multiple mechanisms by which hydrophobic bile acids contribute to genomic instability are discussed, and include oxidative DNA damage, p53 and other mutations, micronuclei formation and aneuploidy. Since bile acids and oxidative stress decrease DNA repair proteins, an increase in DNA damage and increased genomic instability through this mechanism is also described. This review provides a mechanistic explanation for the important link between a Western-style diet and associated increased levels of colon cancer. PMID:21677822

  18. Relationship between duodenal bile acids and colorectal neoplasia.

    PubMed Central

    Moorehead, R J; Campbell, G R; Donaldson, J D; McKelvey, S T

    1987-01-01

    To investigate a possible relationship between bile acids and colorectal neoplasia duodenal bile acids were analysed in 50 patients with colorectal adenomas and 14 with carcinoma. Using gas liquid and high performance liquid chromatography a small, but significant increase in the proportion of chenodeoxycholic acid was found in the bile of adenoma patients compared with controls (mean % +/- SD 31.0 +/- 10.8, 26.4 +/- 8.3, p = 0.01). The difference in the proportions of chenodeoxycholic acid correlated with increasing malignant potential of the adenomas as determined by increasing size, histological type, degree of dysplasia and number present. In carcinoma patients an increase in the proportion of chenodeoxycholic acid was also observed compared with controls (mean % +/- SD, 47.2 +/- 9.6, 28.0 +/- 4.5, p less than 0.01). The proportions of other bile acids in those with adenoma or carcinoma were normal. PMID:3428671

  19. Bile acid synthetic defects and liver disease: a comprehensive review.

    PubMed

    Bove, Kevin E; Heubi, James E; Balistreri, William F; Setchell, Kenneth D R

    2004-01-01

    Bile acid synthetic defects (BASD), uncommon genetic disorders that are responsible for approximately 2% of persistent cholestasis in infants, are reviewed with emphasis on morphology of associated liver disease. The associated liver diseases may be life threatening, and are treatable, usually by replacement of deficient primary bile acids. Specific diagnosis is made by analysis of body fluids (bile, blood, and urine) using fast atom bombardment-mass spectroscopy (FAB-MS) and gas chromatography-mass spectroscopy (GC-MS). Inborn errors have been demonstrated for four single enzymes involved in modification of the sterol nucleus and in five steps in modification of the side-chain to form cholic and chenodeoxycholic acids, the primary bile acids. With few exceptions, BASD cause liver diseases that vary from severe to mild depending on the defect. In three of four known defects of sterol nucleus modification, liver disease is progressive. Progression of liver disease is most rapid when the defect results in accumulation of toxic monohydroxy and unsaturated oxo-bile acids. Liver disease may be transient, delayed in onset and mild. Reduced bile flow caused by atypical bile acids contributes to cholestasis and may be the dominant factor in defects of side-chain synthesis, peroxisomal abiogenesis and S-L-O syndrome. Pathological findings may include intralobular cholestasis with giant cell transformation, prevalence of necrotic hepatocytes including giant cell forms, and hepatitic injury confined to the portal limiting plate where the smallest bile ductules may be injured and where fibrosis typically develops. Interlobular bile ducts are usually spared. Ultrastructure of liver reveals nonspecific changes with the possible exception of unusual canalicular morphology in some defects. The course of BASD may be modified by replacement of deficient primary bile acids, which produces beneficial feedback inhibition of abnormal bile acid production and enhances choluresis. Giant

  20. 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. PMID:16648547

  1. Glucose and Insulin Induction of Bile Acid Synthesis

    PubMed Central

    Li, Tiangang; Francl, Jessica M.; Boehme, Shannon; Ochoa, Adrian; Zhang, Youcai; Klaassen, Curtis D.; Erickson, Sandra K.; Chiang, John Y. L.

    2012-01-01

    Bile acids facilitate postprandial absorption of nutrients. Bile acids also activate the farnesoid X receptor (FXR) and the G protein-coupled receptor TGR5 and play a major role in regulating lipid, glucose, and energy metabolism. Transgenic expression of cholesterol 7α-hydroxylase (CYP7A1) prevented high fat diet-induced diabetes and obesity in mice. In this study, we investigated the nutrient effects on bile acid synthesis. Refeeding of a chow diet to fasted mice increased CYP7A1 expression, bile acid pool size, and serum bile acids in wild type and humanized CYP7A1-transgenic mice. Chromatin immunoprecipitation assays showed that glucose increased histone acetylation and decreased histone methylation on the CYP7A1 gene promoter. Refeeding also induced CYP7A1 in fxr-deficient mice, indicating that FXR signaling did not play a role in postprandial regulation of bile acid synthesis. In streptozocin-induced type I diabetic mice and genetically obese type II diabetic ob/ob mice, hyperglycemia increased histone acetylation status on the CYP7A1 gene promoter, leading to elevated basal Cyp7a1 expression and an enlarged bile acid pool with altered bile acid composition. However, refeeding did not further increase CYP7A1 expression in diabetic mice. In summary, this study demonstrates that glucose and insulin are major postprandial factors that induce CYP7A1 gene expression and bile acid synthesis. Glucose induces CYP7A1 gene expression mainly by epigenetic mechanisms. In diabetic mice, CYP7A1 chromatin is hyperacetylated, and fasting to refeeding response is impaired and may exacerbate metabolic disorders in diabetes. PMID:22144677

  2. [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. PMID:7181465

  3. A tandem mass spectrometric study of bile acids: interpretation of fragmentation pathways and differentiation of steroid isomers.

    PubMed

    Qiao, Xue; Ye, Min; Liu, Chun-fang; Yang, Wen-zhi; Miao, Wen-juan; Dong, Jing; Guo, De-an

    2012-02-01

    Bile acids are steroids with a pentanoic acid substituent at C-17. They are the terminal products of cholesterol excretion, and play critical physiological roles in human and animals. Bile acids are easy to detect but difficult to identify by using mass spectrometry due to their poly-ring structure and various hydroxylation patterns. In this study, fragmentation pathways of 18 free and conjugated bile acids were interpreted by using tandem mass spectrometry. The analyses were conducted on ion trap and triple quadrupole mass spectrometers. Upon collision-induced dissociation, the conjugated bile acids could cleave into glycine or taurine related fragments, together with the steroid skeleton. Fragmentations of free bile acids were further elucidated, especially by atmospheric pressure chemical ionization mass spectrometry in positive ion mode. Aside from universally observed neutral losses, eliminations occurred on bile acid carbon rings were proposed for the first time. Moreover, four isomeric 5β-cholanic acid hydroxyl derivatives (3α,6α-, 3α,7β-, 3α,7α-, and 3α,12α-) were differentiated using electrospray ionization in negative ion mode: 3α,7β-OH substituent inclined to eliminate H(2)O and CH(2)O(2) groups; 3α,6α-OH substituent preferred neutral loss of two H(2)O molecules; 3α,12α-OH substituent apt to lose the carboxyl in the form of CO(2) molecule; and 3α,7α-OH substituent exhibited no further fragmentation after dehydration. This study provided specific interpretation for mass spectra of bile acids. The results could contribute to bile acid analyses, especially in clinical assays and metabonomic studies. PMID:22133544

  4. Hormesis in Cholestatic Liver Disease; Preconditioning with Low Bile Acid Concentrations Protects against Bile Acid-Induced Toxicity

    PubMed Central

    Verhaag, Esther M.; Buist-Homan, Manon; Koehorst, Martijn; Groen, Albert K.; Moshage, Han; Faber, Klaas Nico

    2016-01-01

    Introduction Cholestasis is characterized by accumulation of bile acids and inflammation, causing hepatocellular damage. Still, liver damage markers are highest in acute cholestasis and drop when this condition becomes chronic, indicating that hepatocytes adapt towards the hostile environment. This may be explained by a hormetic response in hepatocytes that limits cell death during cholestasis. Aim To investigate the mechanisms that underlie the hormetic response that protect hepatocytes against experimental cholestatic conditions. Methods HepG2.rNtcp cells were preconditioned (24 h) with sub-apoptotic concentrations (0.1–50 μM) of various bile acids, the superoxide donor menadione, TNF-α or the Farsenoid X Receptor agonist GW4064, followed by a challenge with the apoptosis-inducing bile acid glycochenodeoxycholic acid (GCDCA; 200 μM for 4 h), menadione (50 μM, 6 h) or cytokine mixture (CM; 6 h). Levels of apoptotic and necrotic cell death, mRNA expression of the bile salt export pump (ABCB11) and bile acid sensors, as well as intracellular GCDCA levels were analyzed. Results Preconditioning with the pro-apoptotic bile acids GCDCA, taurocholic acid, or the protective bile acids (tauro)ursodeoxycholic acid reduced GCDCA-induced caspase-3/7 activity in HepG2.rNtcp cells. Bile acid preconditioning did not induce significant levels of necrosis in GCDCA-challenged HepG2.rNtcp cells. In contrast, preconditioning with cholic acid, menadione or TNF-α potentiated GCDCA-induced apoptosis. GCDCA preconditioning specifically reduced GCDCA-induced cell death and not CM- or menadione-induced apoptosis. The hormetic effect of GCDCA preconditioning was concentration- and time-dependent. GCDCA-, CDCA- and GW4064- preconditioning enhanced ABCB11 mRNA levels, but in contrast to the bile acids, GW4064 did not significantly reduce GCDCA-induced caspase-3/7 activity. The GCDCA challenge strongly increased intracellular levels of this bile acid, which was not lowered by GCDCA

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

    PubMed

    Jeong, Eun Sook; Kim, Gabin; Shin, Ho Jung; Park, Se-Myo; Oh, Jung-Hwa; Kim, Yong-Bum; Moon, Kyoung-Sik; Choi, Hyung-Kyoon; Jeong, Jayoung; Shin, Jae-Gook; Kim, Dong Hyun

    2015-10-15

    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 30mg/kg), a well-known hepatotoxic agent, was administered daily to male Sprague-Dawley (SD) rats for 28days. 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 of 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. PMID:26222700

  6. Maternal bile acid transporter deficiency promotes neonatal demise

    PubMed Central

    Zhang, Yuanyuan; Li, Fei; Wang, Yao; Pitre, Aaron; Fang, Zhong-ze; Frank, Matthew W.; Calabrese, Christopher; Krausz, Kristopher W.; Neale, Geoffrey; Frase, Sharon; Vogel, Peter; Rock, Charles O.; Gonzalez, Frank J.; Schuetz, John D.

    2015-01-01

    Intrahepatic cholestasis of pregnancy (ICP) is associated with adverse neonatal survival and is estimated to impact between 0.4 and 5% of pregnancies worldwide. Here we show that maternal cholestasis (due to Abcb11 deficiency) produces neonatal death among all offspring within 24 h of birth due to atelectasis-producing pulmonary hypoxia, which recapitulates the neonatal respiratory distress of human ICP. Neonates of Abcb11-deficient mothers have elevated pulmonary bile acids and altered pulmonary surfactant structure. Maternal absence of Nr1i2 superimposed on Abcb11 deficiency strongly reduces maternal serum bile acid concentrations and increases neonatal survival. We identify pulmonary bile acids as a key factor in the disruption of the structure of pulmonary surfactant in neonates of ICP. These findings have important implications for neonatal respiratory failure, especially when maternal bile acids are elevated during pregnancy, and highlight potential pathways and targets amenable to therapeutic intervention to ameliorate this condition. PMID:26416771

  7. Bile acids induce hepatic differentiation of mesenchymal stem cells

    PubMed Central

    Sawitza, Iris; Kordes, Claus; Götze, Silke; Herebian, Diran; Häussinger, Dieter

    2015-01-01

    Mesenchymal stem cells (MSC) have the potential to differentiate into multiple cell lineages and their therapeutic potential has become obvious. In the liver, MSC are represented by stellate cells which have the potential to differentiate into hepatocytes after stimulation with growth factors. Since bile acids can promote liver regeneration, their influence on liver-resident and bone marrow-derived MSC was investigated. Physiological concentrations of bile acids such as tauroursodeoxycholic acid were able to initiate hepatic differentiation of MSC via the farnesoid X receptor and transmembrane G-protein-coupled bile acid receptor 5 as investigated with knockout mice. Notch, hedgehog, transforming growth factor-β/bone morphogenic protein family and non-canonical Wnt signalling were also essential for bile acid-mediated differentiation, whereas β-catenin-dependent Wnt signalling was able to attenuate this process. Our findings reveal bile acid-mediated signalling as an alternative way to induce hepatic differentiaion of stem cells and highlight bile acids as important signalling molecules during liver regeneration. PMID:26304833

  8. Bile acid accelerates erbB2-induced pro-tumorigenic activities in biliary tract cancer.

    PubMed

    Kitamura, Takuya; Srivastava, Jaya; DiGiovanni, John; Kiguchi, Kaoru

    2015-06-01

    Although very few studies have addressed the molecular and cellular mechanisms underlying the development of biliary tract cancer (BTC), several lines of evidence suggest a role for the erbB receptor family. Overexpression and activation of erbB2 has been reported in a significant percentage of human BTC. Further, we previously reported that overexpression of erbB2 basal epithelial cells of the biliary tract (BK5.erbB2 mouse) led to the development of BTC. However, the mechanisms by which erbB2 overexpression led to the spontaneous development of tumors specifically in the biliary tract are not completely understood. The goals of the current study were to (1) determine whether a cooperative relationship between bile acid exposure and erbB2 activation exists during biliary tract carcinogenesis and (2) to characterize the mechanism(s) underlying bile acid-mediated biliary tract carcinogenesis in cells with activated erbB2. In this study, we demonstrated that the secondary conjugated bile acid, taurochenodeoxycholic acid (TCDC), increased proliferation of primary cultured gallbladder epithelial cells from BK5.erbB2 mice and human BTC cells. TCDC treatment activated EGFR/erbB2 and downstream signaling molecules in both primary cultured cells and human BTC cells. TCDC also increased the expression of epidermal growth factor receptor (EGFR) ligands and TACE activity in human BTC cells. Inhibition of src activation led to attenuation of bile-induced upregulation of TACE activity as well as signaling through the EGFR/erbB2, suggesting that during the development of BTC erbB2 overexpression/activation accelerates the bile acid-induced signaling cascade: bile acid → src → TACE → EGFR/erbB2 → downstream signaling. We also provide direct evidence that bile acids possess tumor promoting capacity in epithelial cells overexpressing erbB2 using the two-stage skin carcinogenesis model. Collectively these findings suggest cooperative roles for bile acid and

  9. 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. PMID:27236139

  10. Morphologic changes in livers of hamsters treated with high doses of ursodeoxycholic acid: correlation with bile acids in bile.

    PubMed

    Mamianetti, A; Konopka, H F; Lago, N; Vescina, C; Scarlato, E; Carducci, C N

    1994-01-01

    The effects of high doses of ursodeoxycholic acid on bile acid composition and the liver morphology was examined in 60 male Syrian golden hamsters. The animals were allocated to five groups: I, control; II and IV received 0.5 g and 1 g of ursodeoxycholic acid per 100 g of standard diet respectively over 30 days and III and V received 0.5 g and 1 g of ursodeoxycholic acid per 100 g of standard diet respectively over 60 days. Bile acids were determined by high performance liquid chromatography. In all treated groups there was a significant increase in chenodeoxycholic and lithocholic acid in the bile. The mean glyco/tauro ratio was significantly higher than in the control group, reaching values > 1 for individual bile acids, except for lithocholic acid values which remained < 1. Under light microscopy, the livers of the hamsters showed damage which was dose/time related, namely portal inflammatory infiltrate, bile duct proliferation, cholestasis, fat infiltration and necrosis. Electron microscopy revealed pronounced changes starting with microvilli edema and extending to canalicular membrane destruction and necrosis. The changes observed in the relation glyco/tauro lithocholic acids, may be due to defence mechanisms to avoid hepatotoxicity. The hepatotoxicity resulting from ursodeoxycholic acid administration is presumed to be due primarily to lithocholic acid or some lithocholic acid metabolite. PMID:8058592

  11. Kinetics for the synthetic bile acid 75-selenohomocholic acid-taurine in humans: comparison with (/sup 14/C)taurocholate

    SciTech Connect

    Jazrawi, R.P.; Ferraris, R.; Bridges, C.; Northfield, T.C.

    1988-07-01

    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 less 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.

  12. Feed-forward regulation of bile acid detoxification by CYP3A4: studies in humanized transgenic mice.

    PubMed

    Stedman, Catherine; Robertson, Graham; Coulter, Sally; Liddle, Christopher

    2004-03-19

    Bile acids are potentially toxic end products of cholesterol metabolism and their concentrations must be tightly regulated. Homeostasis is maintained by both feed-forward regulation and feedback regulation. We used humanized transgenic mice incorporating 13 kb of the 5' regulatory flanking sequence of CYP3A4 linked to a lacZ reporter gene to explore the in vivo relationship between bile acids and physiological adaptive CYP3A gene regulation in acute cholestasis after bile duct ligation (BDL). Male transgenic mice were subjected to BDL or sham surgery prior to sacrifice on days 3, 6, and 10, and others were injected with intraperitoneal lithocholic acid (LCA) or vehicle alone. BDL resulted in marked hepatic activation of the CYP3A4/lacZ transgene in pericentral hepatocytes, with an 80-fold increase in transgene activation by day 10. Individual bile acids were quantified by liquid chromatography/mass spectrometry. Serum 6beta-hydroxylated bile acids were increased following BDL, confirming the physiological relevance of endogenous Cyp3a induction to bile acid detoxification. Although concentrations of conjugated primary bile acids increased after BDL, there was no increase in LCA, a putative PXR ligand, indicating that this cannot be the only endogenous bile acid mediating this protective response. Moreover, in LCA-treated animals, 5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside staining showed hepatic activation of the CYP3A4 transgene only on the liver capsular surface, and minimal parenchymal induction, despite significant liver injury. This study demonstrates that CYP3A up-regulation is a significant in vivo adaptive response to cholestasis. However, this up-regulation is not dependent on increases in circulating LCA and the role of other bile acids as regulatory molecules requires further exploration. PMID:14681232

  13. Detection of pentachlorophenol and its glucuronide and sulfate conjugates in fish bile and exposure water

    SciTech Connect

    Stehly, G.R.; Hayton, W.L.

    1988-08-01

    The glucuronide and sulfate conjugates of pentachlorophenol (PCP) that were present in the bile and exposure water of goldfish (Carassius auratus) were used to develop methodology to quantify PCP and its metabolites. Reverse phase HPLC with radioactivity detection separated PCP and its metabolites, and was used to verify a method of quantification that used differential extraction and scintillation counting. Extractions of aqueous phase at pH 2 or 8, with butanol, ethyl acetate, or ether indicated that ether at pH 8 best separated PCP from its metabolites. The sulfate conjugate of PCP was the major metabolite produced when goldfish were exposed to 125 micrograms UC-PCP/l. It was present primarily in the exposure water, but also appeared in the bile.

  14. Biofilm Formation and Detachment in Gram-Negative Pathogens Is Modulated by Select Bile Acids.

    PubMed

    Sanchez, Laura M; Cheng, Andrew T; Warner, Christopher J A; Townsley, Loni; Peach, Kelly C; Navarro, Gabriel; Shikuma, Nicholas J; Bray, Walter M; Riener, Romina M; Yildiz, Fitnat H; Linington, Roger G

    2016-01-01

    Biofilms are a ubiquitous feature of microbial community structure in both natural and host environments; they enhance transmission and infectivity of pathogens and provide protection from human defense mechanisms and antibiotics. However, few natural products are known that impact biofilm formation or persistence for either environmental or pathogenic bacteria. Using the combination of a novel natural products library from the fish microbiome and an image-based screen for biofilm inhibition, we describe the identification of taurine-conjugated bile acids as inhibitors of biofilm formation against both Vibrio cholerae and Pseudomonas aeruginosa. Taurocholic acid (1) was isolated from the fermentation broth of the fish microbiome-derived strain of Rhodococcus erythropolis and identified using standard NMR and MS methods. Screening of the twelve predominant human steroidal bile acid components revealed that a subset of these compounds can inhibit biofilm formation, induce detachment of preformed biofilms under static conditions, and that these compounds display distinct structure-activity relationships against V. cholerae and P. aeruginosa. Our findings highlight the significance of distinct bile acid components in the regulation of biofilm formation and dispersion in two different clinically relevant bacterial pathogens, and suggest that the bile acids, which are endogenous mammalian metabolites used to solubilize dietary fats, may also play a role in maintaining host health against bacterial infection. PMID:26992172

  15. Lipid binding protein response to a bile acid library: a combined NMR and statistical approach.

    PubMed

    Tomaselli, Simona; Pagano, Katiuscia; Boulton, Stephen; Zanzoni, Serena; Melacini, Giuseppe; Molinari, Henriette; Ragona, Laura

    2015-11-01

    Primary bile acids, differing in hydroxylation pattern, are synthesized from cholesterol in the liver and, once formed, can undergo extensive enzyme-catalysed glycine/taurine conjugation, giving rise to a complex mixture, the bile acid pool. Composition and concentration of the bile acid pool may be altered in diseases, posing a general question on the response of the carrier (bile acid binding protein) to the binding of ligands with different hydrophobic and steric profiles. A collection of NMR experiments (H/D exchange, HET-SOFAST, ePHOGSY NOESY/ROESY and (15) N relaxation measurements) was thus performed on apo and five different holo proteins, to monitor the binding pocket accessibility and dynamics. The ensemble of obtained data could be rationalized by a statistical approach, based on chemical shift covariance analysis, in terms of residue-specific correlations and collective protein response to ligand binding. The results indicate that the same residues are influenced by diverse chemical stresses: ligand binding always induces silencing of motions at the protein portal with a concomitant conformational rearrangement of a network of residues, located at the protein anti-portal region. This network of amino acids, which do not belong to the binding site, forms a contiguous surface, sensing the presence of the bound lipids, with a signalling role in switching protein-membrane interactions on and off. PMID:26260520

  16. Biofilm Formation and Detachment in Gram-Negative Pathogens Is Modulated by Select Bile Acids

    PubMed Central

    Townsley, Loni; Peach, Kelly C.; Navarro, Gabriel; Shikuma, Nicholas J.; Bray, Walter M.; Riener, Romina M.; Yildiz, Fitnat H.; Linington, Roger G.

    2016-01-01

    Biofilms are a ubiquitous feature of microbial community structure in both natural and host environments; they enhance transmission and infectivity of pathogens and provide protection from human defense mechanisms and antibiotics. However, few natural products are known that impact biofilm formation or persistence for either environmental or pathogenic bacteria. Using the combination of a novel natural products library from the fish microbiome and an image-based screen for biofilm inhibition, we describe the identification of taurine-conjugated bile acids as inhibitors of biofilm formation against both Vibrio cholerae and Pseudomonas aeruginosa. Taurocholic acid (1) was isolated from the fermentation broth of the fish microbiome-derived strain of Rhodococcus erythropolis and identified using standard NMR and MS methods. Screening of the twelve predominant human steroidal bile acid components revealed that a subset of these compounds can inhibit biofilm formation, induce detachment of preformed biofilms under static conditions, and that these compounds display distinct structure-activity relationships against V. cholerae and P. aeruginosa. Our findings highlight the significance of distinct bile acid components in the regulation of biofilm formation and dispersion in two different clinically relevant bacterial pathogens, and suggest that the bile acids, which are endogenous mammalian metabolites used to solubilize dietary fats, may also play a role in maintaining host health against bacterial infection. PMID:26992172

  17. Dose-response of five bile acids on serum and liver bile Acid concentrations and hepatotoxicty in mice.

    PubMed

    Song, Peizhen; Zhang, Youcai; Klaassen, Curtis D

    2011-10-01

    Feeding bile acids (BAs) to rodents has been used to study BA signaling and toxicity in vivo. However, little is known about the effect of feeding BAs on the concentrations of BAs in serum and liver as well as the dose of the fed BAs that causes liver toxicity. The present study was designed to investigate the relative hepatotoxicity of individual BAs by feeding mice cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA), or ursodeoxycholic acid (UDCA) at concentrations of 0.01, 0.03, 0.1, 0.3, 1.0, or 3% in their diet for 7 days. The data demonstrate that (1) the ability of the fed BAs to produce hepatotoxicity is UDCAconjugation enzymes are saturated by feeding UDCA at concentrations higher than 0.3%. In conclusion, the findings of the present study provide guidance for choosing the feeding concentrations of BAs in mice and will aid in interpreting BA hepatotoxicity as well as BA-mediated gene regulation. PMID:21747115

  18. Se-75-labeled bile acid analogs, new radiopharmaceuticals for investigating the enterohepatic circulation

    SciTech Connect

    Boyd, G.S.; Merrick, M.V.; Monks, R.; Thomas, I.L.

    1981-08-01

    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 enterohepatic 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.

  19. 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

  20. Bile acids stimulate chloride secretion through CFTR and calcium-activated Cl- channels in Calu-3 airway epithelial cells.

    PubMed

    Hendrick, Siobhán M; Mroz, Magdalena S; Greene, Catherine M; Keely, Stephen J; Harvey, Brian J

    2014-09-01

    Bile acids resulting from the aspiration of gastroesophageal refluxate are often present in the lower airways of people with cystic fibrosis and other respiratory distress diseases. Surprisingly, there is little or no information on the modulation of airway epithelial ion transport by bile acids. The secretory effect of a variety of conjugated and unconjugated secondary bile acids was investigated in Calu-3 airway epithelial cells grown under an air-liquid interface and mounted in Ussing chambers. Electrogenic transepithelial ion transport was measured as short-circuit current (Isc). The taurine-conjugated secondary bile acid, taurodeoxycholic acid (TDCA), was found to be the most potent modulator of basal ion transport. Acute treatment (5 min) of Calu-3 cells with TDCA (25 μM) on the basolateral side caused a stimulation of Isc, and removal of extracellular Cl(-) abolished this response. TDCA produced an increase in the cystic fibrosis transmembrane conductance regulator (CFTR)-dependent current that was abolished by pretreatment with the CFTR inhibitor CFTRinh172. TDCA treatment also increased Cl(-) secretion through calcium-activated chloride (CaCC) channels and increased the Na(+)/K(+) pump current. Acute treatment with TDCA resulted in a rapid cellular influx of Ca(2+) and increased cAMP levels in Calu-3 cells. Bile acid receptor-selective activation with INT-777 revealed TGR5 localized at the basolateral membrane as the receptor involved in TDCA-induced Cl(-) secretion. In summary, we demonstrate for the first time that low concentrations of bile acids can modulate Cl(-) secretion in airway epithelial cells, and this effect is dependent on both the duration and sidedness of exposure to the bile acid. PMID:24993131

  1. Antibody conjugates with unnatural amino acids.

    PubMed

    Hallam, Trevor J; Wold, Erik; Wahl, Alan; Smider, Vaughn V

    2015-06-01

    Antibody conjugates are important in many areas of medicine and biological research, and antibody-drug conjugates (ADCs) are becoming an important next generation class of therapeutics for cancer treatment. Early conjugation technologies relied upon random conjugation to multiple amino acid side chains, resulting in heterogeneous mixtures of labeled antibody. Recent studies, however, strongly support the notion that site-specific conjugation produces a homogeneous population of antibody conjugates with improved pharmacologic properties over randomly coupled molecules. Genetically incorporated unnatural amino acids (uAAs) allow unique orthogonal coupling strategies compared to those used for the 20 naturally occurring amino acids. Thus, uAAs provide a novel paradigm for creation of next generation ADCs. Additionally, uAA-based site-specific conjugation could also empower creation of additional multifunctional conjugates important as biopharmaceuticals, diagnostics, or reagents. PMID:25898256

  2. Novel type of ornithine-glutathione double conjugate excreted as a major metabolite into the bile of rats administered clebopride

    SciTech Connect

    Ishizuka, T.; Komiya, I.; Hiratsuka, A.; Watabe, T. )

    1990-06-01

    Rats orally given radioactive Clebopride ((14C)CP; N-(1'-benzyl-4'-piperidyl)-2-(14C)methoxy-4-amino-5-chlorobenzamide++ +), an antiulcer agent, excreted a novel type of ornithine (Orn)-GSH double conjugate in the bile as a major metabolite ((14C)BMCP), corresponding to 18% of the dose. The present study provides the first evidence for Orn conjugation of a xenobiotic in mammals and demonstrates that the structure of the radioactive conjugate differs fundamentally from those known in birds and reptiles. The structure of the biliary metabolite, (14C)BMCP, purified to homogeneity by silica gel thin layer and reverse phase high pressure liquid chromatography, was elucidated as S-(2-ornithylamino-4-(14C)methoxy-5-(1'-methyl-4'-piperidylamin o) carboxyphenyl)glutathione, based mainly on the following facts: (1) BMCP showed a protonated molecular ion (M + H)+ peak at m/z 683 in the secondary ion mass spectrum and (2) (14C)BMCP afforded Orn, glutamic acid, glycine, S-(2-amino-4-(14C)methoxy-5-carboxyphenyl)cysteine (( 14C)AMCC), and 1-methyl-4-aminopiperidine (MAP) quantitatively, in an equal molar ratio, by complete hydrolysis with peptidase. Thus, BMCP was a metabolite with three enzymatically hydrolyzable amide bonds in addition to the one existing originally in the parent structure of the drug, which produces MAP by peptic digestion. Of the three additional amide bonds of BMCP, one was a novel type of bond formed by condensation of the alpha-carboxylic acid group of Orn with the primary aromatic amino group of the drug and the other two were in the S-glutathionyl residue, substituted for the chlorine atom vicinal to the Orn-conjugating primary amino group in the aromatic ring and affording glutamic acid, glycine, and the S-cysteine conjugate AMCC by hydrolysis of BMCP with the peptidase.

  3. Bile acids and derivatives, their nuclear receptors FXR, PXR and ligands: role in health and disease and their therapeutic potential.

    PubMed

    Zimber, Amazia; Gespach, Christian

    2008-06-01

    Bile acids, their physiology and metabolism, their role in carcinogenesis and other major human diseases are recently undergoing significant progress. Starting in 1999 when the orphan nuclear receptor FXR was shown to be specifically activated by bile acids, these compounds became part of the arsenal of ligands of the steroid hormone superfamily of nuclear receptors, including receptors of Vitamin D3, retinoids (RAR, RXR), and thyroid hormone. Another decisive discovery pointed later that the pregnane X-receptor (PXR) is activated by the endogenous toxic lithocholic acid, as well as several xenobiotics and drugs. Bile acids have recently emerged as key regulators of their own metabolism, and of lipid and carbohydrate metabolism. They have important role as promoters of esophageal and colon cancers, cholangiocarcinoma, as well as new implications in breast cancer development and metastasis. This Review will emphasize novel aspects of bile acids, FXR and PXR as regulators of interfaces at cell proliferation and differentiation, cell death, survival, invasion, and metastasis during normal development and cancer progression. Signaling pathways controlled by bile acids will be presented and discussed in relation to their impact on gene expression. The biological and pharmacological significance of bile acids and their recently developed synthetic derivatives and conjugates, as well as new development in the design of FXR agonists and antagonists for clinical applications in cancer prevention and therapy, will be evaluated. This part includes advances in the utilization of bile acid transporters in drug resistance, therapeutic targeting and delivery of anticancer drugs, as well as therapeutic combinations using new bile acid derivatives, sequestrating agents and reabsorption inhibitors, and their limitations. PMID:18537536

  4. Bile salt recognition by human liver fatty acid binding protein.

    PubMed

    Favretto, Filippo; Santambrogio, Carlo; D'Onofrio, Mariapina; Molinari, Henriette; Grandori, Rita; Assfalg, Michael

    2015-04-01

    Fatty acid binding proteins (FABPs) act as intracellular carriers of lipid molecules, and play a role in global metabolism regulation. Liver FABP (L-FABP) is prominent among FABPs for its wide ligand repertoire, which includes long-chain fatty acids as well as bile acids (BAs). In this work, we performed a detailed molecular- and atomic-level analysis of the interactions established by human L-FABP with nine BAs to understand the binding specificity for this important class of cholesterol-derived metabolites. Protein-ligand complex formation was monitored using heteronuclear NMR, steady-state fluorescence spectroscopy, and mass spectrometry. BAs were found to interact with L-FABP with dissociation constants in the narrow range of 0.6-7 μm; however, the diverse substitution patterns of the sterol nucleus and the presence of side-chain conjugation resulted in complexes endowed with various degrees of conformational heterogeneity. Trihydroxylated BAs formed monomeric complexes in which single ligand molecules occupied similar internal binding sites, based on chemical-shift perturbation data. Analysis of NMR line shapes upon progressive addition of taurocholate indicated that the binding mechanism departed from a simple binary association equilibrium, and instead involved intermediates along the binding path. The co-linear chemical shift behavior observed for L-FABP complexes with cholate derivatives added insight into conformational dynamics in the presence of ligands. The observed spectroscopic features of L-FABP/BA complexes, discussed in relation to ligand chemistry, suggest possible molecular determinants of recognition, with implications regarding intracellular BA transport. Our findings suggest that human L-FABP is a poorly selective, universal BA binder. PMID:25639618

  5. [Study on effect of artificial CsB and its components on bile acid metabolism in rats with liver fibrosis and its mechanism].

    PubMed

    Zhang, Xing; Li, Feng-Hua; Liu, Ping; Liu, Jia; Wang, Shuang

    2013-11-01

    Bile acid is a type of metabolite degraded from cholesterol in liver. Its accumulation in liver could cause liver diseases, liver damage and liver fibrosis. In this experiment, dimethyl nitrosamine (DMN) liver fibrosis was established in rats. The rats were delivered into the normal group, the model group and four treated groups. After the four-week modeling, the treated groups were orally administered with drugs for 2 weeks, whereas the model and normal groups were given equal amount of sterile water at the same time. In the experiment, serum bile acid was taken the as marker, and liver function indexes and changes in bile acid metabolism were detected and observed to identify liver damage-related bile acid targets. It was the first time to evaluate the reverse effect of artificial CsB and its components on liver fibrosis in rats with bile acid metabolic level, and discuss its potential mechanism. The main study contents and results are as follows: a quantitative analysis was made on totally 17 endogenous bile acids, including taurocholic acid conjugated bile acid, glycine conjugated bile acid and free bile acid, and a liver damage evaluation was made for the model according to the detection of serum biochemical indexes and the pathological biopsy. After modeling, ALT, AST activity and TBil content significantly increased, whereas Alb significantly decreased. According to the pathological biopsy HE staining, the model group showed damage in normal hepatic lobule structure, liver cell edema and connective tissue proliferation in portal area; The treated groups showed mitigation in pathological changes to varying degrees. Cordyceps sinensis and its components may impact the bile acid metabolism in rats by activating HDCA, TCA, TCDCA, TLCA, TUDCA, UDCA, THDCA metabolim-related receptors or blocking relevant signaling pathway. PMID:24558881

  6. Bile acid receptors and nonalcoholic fatty liver disease

    PubMed Central

    Yuan, Liyun; Bambha, Kiran

    2015-01-01

    With the high prevalence of obesity, diabetes, and other features of the metabolic syndrome in United States, nonalcoholic fatty liver disease (NAFLD) has inevitably become a very prevalent chronic liver disease and is now emerging as one of the leading indications for liver transplantation. Insulin resistance and derangement of lipid metabolism, accompanied by activation of the pro-inflammatory response and fibrogenesis, are essential pathways in the development of the more clinically significant form of NAFLD, known as nonalcoholic steatohepatitis (NASH). Recent advances in the functional characterization of bile acid receptors, such as farnesoid X receptor (FXR) and transmembrane G protein-coupled receptor (TGR) 5, have provided further insight in the pathophysiology of NASH and have led to the development of potential therapeutic targets for NAFLD and NASH. Beyond maintaining bile acid metabolism, FXR and TGR5 also regulate lipid metabolism, maintain glucose homeostasis, increase energy expenditure, and ameliorate hepatic inflammation. These intriguing features have been exploited to develop bile acid analogues to target pathways in NAFLD and NASH pathogenesis. This review provides a brief overview of the pathogenesis of NAFLD and NASH, and then delves into the biological functions of bile acid receptors, particularly with respect to NASH pathogenesis, with a description of the associated experimental data, and, finally, we discuss the prospects of bile acid analogues in the treatment of NAFLD and NASH. PMID:26668692

  7. [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. PMID:6732204

  8. Gut microbiota regulates bile acid metabolism by reducing the levels of tauro-beta-muricholic acid, a naturally occurring FXR antagonist.

    PubMed

    Sayin, Sama I; Wahlström, Annika; Felin, Jenny; Jäntti, Sirkku; Marschall, Hanns-Ulrich; Bamberg, Krister; Angelin, Bo; Hyötyläinen, Tuulia; Orešič, Matej; Bäckhed, Fredrik

    2013-02-01

    Bile acids are synthesized from cholesterol in the liver and further metabolized by the gut microbiota into secondary bile acids. Bile acid synthesis is under negative feedback control through activation of the nuclear receptor farnesoid X receptor (FXR) in the ileum and liver. Here we profiled the bile acid composition throughout the enterohepatic system in germ-free (GF) and conventionally raised (CONV-R) mice. We confirmed a dramatic reduction in muricholic acid, but not cholic acid, levels in CONV-R mice. Rederivation of Fxr-deficient mice as GF demonstrated that the gut microbiota regulated expression of fibroblast growth factor 15 in the ileum and cholesterol 7α-hydroxylase (CYP7A1) in the liver by FXR-dependent mechanisms. Importantly, we identified tauro-conjugated beta- and alpha-muricholic acids as FXR antagonists. These studies suggest that the gut microbiota not only regulates secondary bile acid metabolism but also inhibits bile acid synthesis in the liver by alleviating FXR inhibition in the ileum. PMID:23395169

  9. High performance liquid chromatography-tandem mass spectrometry for the determination of bile acid concentrations in human plasma.

    PubMed

    Xiang, Xiaoqiang; Han, Yi; Neuvonen, Mikko; Laitila, Jouko; Neuvonen, Pertti J; Niemi, Mikko

    2010-01-01

    We report a sensitive and robust method to determine cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA), ursodeoxycholic acid (UDCA), and their taurine- and glycine-conjugate concentrations in human plasma using liquid chromatography-tandem mass spectrometry. Activated charcoal was utilized to prepare bile acid-free plasma, which served as the biological matrix for the preparation of standard and quality control samples. Plasma sample preparation involved solid-phase extraction. A total of 16 bile acids and 5 internal standards were separated on a reverse column by gradient elution and detected by tandem mass spectrometry in negative ion mode. The calibration curve was linear for all the bile acids over a range of 0.005-5micromol/L. The extraction recoveries for all the analytes fell in the range of 88-101%. Intra-day and inter-day coefficients of variation were all below 10%. A stability test showed that all the bile acids were stable in plasma for at least 6h at room temperature, at least three freeze-thaw cycles, in the -70 degrees C or -20 degrees C freezer for 2 months, and also in the reconstitution solution at 8 degrees C for 48h. Comparison of the matrix effect of bile acid-free plasma with that of real plasma indicated that the charcoal purification procedure did not affect the properties of charcoal-purified plasma as calibration matrix. This method has been used to determine the bile acid concentrations in more than 300 plasma samples from healthy individuals. In conclusion, this method is suitable for the simultaneous quantification of individual bile acids in human plasma. PMID:19945922

  10. Differential effects of cyclosporin A on transport of bile acids by rat hepatocytes: relationship to individual serum bile acid levels.

    PubMed

    Azer, S A; Stacey, N H

    1994-02-01

    Cyclosporin A treatment has been reported to induce hepatotoxicity marked by a rise in total serum bile acid and total bilirubin. The mechanism of cyclosporin A-induced hepatotoxicity seems to be related to interference with hepatocellular transport of these substrates although this remains to be fully substantiated. The purpose of this study was to investigate whether the hepatocellular uptake of the different bile acids, in the presence of cyclosporin A, is consistent with the changes in their respective individual serum bile acid concentrations. High-performance liquid chromatography has been used to assay individual serum bile acids in cyclosporin A-treated rats at doses of 0.1, 1, and 10 mg/kg/day for 4 days. Control rats were treated with Cremophor (1 ml/kg/day). At the higher doses, cyclosporin A produced a significant increase in levels of cholic acid, taurocholic acid, chenodeoxycholic acid, and deoxycholic acid compared with controls. Serum glycocholate was unaffected even at the highest dose. Inhibition of initial rate of uptake and accumulation of [14C]cholic acid, [14C]chenodeoxycholic acid, and [14C]deoxycholic acid by isolated rat hepatocytes was consistent with the changes in their respective serum bile acids. Coincubation of rat hepatocytes with unlabeled cholic acid (100 microM), the major serum bile acid in cyclosporin A-treated rats, showed a further inhibitory effect on [14C]cholic acid and [14C]deoxycholic acid accumulation. The initial rate of uptake of [14C]glycocholate was also inhibited. However, accumulation of glycocholic acid did not show significant changes at the longer incubation times (2-30 min). In addition, coincubation of rat hepatocytes with unlabeled cholic acid (100 microM) plus cyclosporin A did not induce any inhibition of glycocholate accumulation. Together, these differences provide an explanation for the unchanged serum levels of glycocholate. In conclusion, the changes in individual serum bile acids in cyclosporin A

  11. Endogenous bile acid disposition in rat and human sandwich-cultured hepatocytes

    SciTech Connect

    Marion, Tracy L.; Perry, Cassandra H.; St Claire, Robert L.; Brouwer, Kim L.R.

    2012-05-15

    Sandwich-cultured hepatocytes (SCH) are used commonly to investigate hepatic transport protein-mediated uptake and biliary excretion of substrates. However, little is known about the disposition of endogenous bile acids (BAs) in SCH. In this study, four endogenous conjugated BAs common to rats and humans [taurocholic acid (TCA), glycocholic acid (GCA), taurochenodeoxycholic acid (TCDCA), and glycochenodeoxycholic acid (GCDCA)], as well as two BA species specific to rodents (α- and β-tauromuricholic acid; α/β TMCA), were profiled in primary rat and human SCH. Using B-CLEAR{sup ®} technology, BAs were measured in cells + bile canaliculi, cells, and medium of SCH by LC-MS/MS. Results indicated that, just as in vivo, taurine-conjugated BA species were predominant in rat SCH, while glycine-conjugated BAs were predominant in human SCH. Total intracellular BAs remained relatively constant over days in culture in rat SCH. Total BAs in control (CTL) cells + bile, cells, and medium were approximately 3.4, 2.9, and 8.3-fold greater in human than in rat. The estimated intracellular concentrations of the measured total BAs were 64.3 ± 5.9 μM in CTL rat and 183 ± 56 μM in CTL human SCH, while medium concentrations of the total BAs measured were 1.16 ± 0.21 μM in CTL rat SCH and 9.61 ± 6.36 μM in CTL human SCH. Treatment of cells for 24 h with 10 μM troglitazone (TRO), an inhibitor of the bile salt export pump (BSEP) and the Na{sup +}-taurocholate cotransporting polypeptide (NTCP), had no significant effect on endogenous BAs measured at the end of the 24-h culture period, potentially due to compensatory mechanisms that maintain BA homeostasis. These data demonstrate that BAs in SCH are similar to in vivo, and that SCH may be a useful in vitro model to study alterations in BA disposition if species differences are taken into account. -- Highlights: ► Bile acids (BAs) were measured in rat and human sandwich-cultured hepatocytes (SCH). ► Cell and medium BA

  12. Amonia gas: an improved reagent for chemical ionization mass spectrometry of bile acid methyl ester acetates

    SciTech Connect

    DeMark, B.R.; Klein, P.D.

    1981-01-01

    The ammonia chemical ionization mass spectra of 28 methyl ester acetate derivatives of bile acids and related compounds have been determined by gas-liquid chromatography-mass spectrometry. Advantages of ammonia ionization over the previously studied isobutane ionization include a 130 to 270% enhancement in the sensitivity of base peak monitoring, and direct determination of molecular weight from the base peak (M + NH/sub 4//sup +/) in the mass spectrum of any of the derivatives. Minor ions in the ammonia spectra also allow selective detection of 3-keto compounds and can indicate unsaturation or double bond conjugation in the molecule. The significance of these studies for the detection and quantitation of bile acids is discussed. 2 tables.

  13. Specific /sup 125/I-radioimmunoassay for cholylglycine, a bile acid, in serum

    SciTech Connect

    Miller, P.; Weiss, S.; Cornell, M.; Dockery, J.

    1981-10-01

    The concentration of the conjugated bile acid, cholylglycine, in serum is a sensitive and specific indicator of hepatic function. We describe a convenient, specific, and precise radioimmunoassay for cholylglycine, in which /sup 125/I-labeled cholylglycyltyrosine is used as tracer. In addition, a blocking agent in the buffer system eliminates binding of bile acids to serum albumin. Therefore no extraction is required. We found no interference by (a) abnormal concentrations of albumin or gamma-globulin, (b) lipemic sera, (c) hemolyzed sera, (d) anticoagulants, or (e) various commonly used drugs. The reference interval for fasting subjects is estimated to be 0.0 to 0.6 mg/L. Our clinical studies show that serum cholylglycine concentrations are usually abnormal in most hepatobiliary diseases, such as viral hepatitis, alcoholic liver disease, cirrhosis, and pediatric liver diseases.

  14. Effect of submicellar concentrations of conjugated and unconjugated bile salts on the lipid bilayer membrane.

    PubMed

    Mohapatra, Monalisa; Mishra, Ashok K

    2011-11-15

    The interaction of submicellar concentrations of various physiologically important unconjugated [sodium deoxycholate (NaDC), sodium cholate (NaC)] and conjugated [sodium glycodeoxycholate (NaGDC), sodium glycocholate (NaGC), sodium taurodeoxycholate (NaTDC), sodium taurocholate (NaTC)] bile salts with dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) small unilamellar vesicles in solid gel (SG) and liquid crystalline (LC) phases was investigated using the excited-state prototropism of 1-naphthol. Steady-state and time-resolved fluorescence of the two excited-state prototropic forms of 1-naphthol indicate that submicellar bile salt concentration induces hydration of the lipid bilayer membrane into the core region. This hydration effect is a general phenomenon of the bile salts studied. The bilayer hydration efficiency of the bile salt follows the order NaDC > NaC > NaGDC > NaTDC > NaGC > NaTC for both DPPC and DMPC vesicles in their SG and LC phases. PMID:21973323

  15. Serum bile acid profiling reflects enterohepatic detoxification state and intestinal barrier function in inflammatory bowel disease

    PubMed Central

    Gnewuch, Carsten; Liebisch, Gerhard; Langmann, Thomas; Dieplinger, Benjamin; Mueller, Thomas; Haltmayer, Meinhard; Dieplinger, Hans; Zahn, Alexandra; Stremmel, Wolfgang; Rogler, Gerhard; Schmitz, Gerd

    2009-01-01

    AIM: To determine free and conjugated serum bile acid (BA) levels in inflammatory bowel disease (IBD) subgroups with defined clinical manifestations. METHODS: Comprehensive serum BA profiling was performed in 358 IBD patients and 310 healthy controls by liquid chromatography coupled to electrospray ionization tandem mass spectrometry. RESULTS: Serum levels of hyodeoxycholic acid, the CYP3A4-mediated detoxification product of the secondary BA lithocholic acid (LCA), was increased significantly in Crohn’s disease (CD) and ulcerative colitis (UC), while most other serum BA species were decreased significantly. Total BA, total BA conjugate, and total BA glycoconjugate levels were decreased only in CD, whereas total unconjugated BA levels were decreased only in UC. In UC patients with hepatobiliary manifestations, the conjugated primary BAs glycocholic acid, taurocholic acid, and glycochenodeoxycholic acid were as significantly increased as the secondary BAs LCA, ursodeoxycholic acid, and tauroursodeoxycholic acid compared to UC patients without hepatobiliary manifestations. Finally, we found that in ileocecal resected CD patients, the unconjugated primary BAs, cholic acid and chenodeoxycholic acid, were increased significantly compared to controls and patients without surgical interventions. CONCLUSION: Serum BA profiling in IBD patients that indicates impaired intestinal barrier function and increased detoxification is suitable for advanced diagnostic characterization and differentiation of IBD subgroups with defined clinical manifestations. PMID:19575493

  16. 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.

  17. Bile acid nuclear receptor FXR and digestive system diseases

    PubMed Central

    Ding, Lili; Yang, Li; Wang, Zhengtao; Huang, Wendong

    2015-01-01

    Bile acids (BAs) are not only digestive surfactants but also important cell signaling molecules, which stimulate several signaling pathways to regulate some important biological processes. The bile-acid-activated nuclear receptor, farnesoid X receptor (FXR), plays a pivotal role in regulating bile acid, lipid and glucose homeostasis as well as in regulating the inflammatory responses, barrier function and prevention of bacterial translocation in the intestinal tract. As expected, FXR is involved in the pathophysiology of a wide range of diseases of gastrointestinal tract, including inflammatory bowel disease, colorectal cancer and type 2 diabetes. In this review, we discuss current knowledge of the roles of FXR in physiology of the digestive system and the related diseases. Better understanding of the roles of FXR in digestive system will accelerate the development of FXR ligands/modulators for the treatment of digestive system diseases. PMID:26579439

  18. Bile acid nuclear receptor FXR and digestive system diseases.

    PubMed

    Ding, Lili; Yang, Li; Wang, Zhengtao; Huang, Wendong

    2015-03-01

    Bile acids (BAs) are not only digestive surfactants but also important cell signaling molecules, which stimulate several signaling pathways to regulate some important biological processes. The bile-acid-activated nuclear receptor, farnesoid X receptor (FXR), plays a pivotal role in regulating bile acid, lipid and glucose homeostasis as well as in regulating the inflammatory responses, barrier function and prevention of bacterial translocation in the intestinal tract. As expected, FXR is involved in the pathophysiology of a wide range of diseases of gastrointestinal tract, including inflammatory bowel disease, colorectal cancer and type 2 diabetes. In this review, we discuss current knowledge of the roles of FXR in physiology of the digestive system and the related diseases. Better understanding of the roles of FXR in digestive system will accelerate the development of FXR ligands/modulators for the treatment of digestive system diseases. PMID:26579439

  19. 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

  20. A prospective study of faecal bile acids and colorectal cancer.

    PubMed

    Haines, A; Hill, M J; Thompson, M H; Owen, R W; Williams, R E; Meade, T W; Wilkes, H; Griffin, M

    2000-10-01

    A prospective study of 7079 people aged 45-74 recruited through general practices in South Wales, Herefordshire and Edinburgh, Scotland was undertaken to test the hypothesis that faecal bile acids are implicated in the causation of large bowel cancer. The population was recruited between 1974 and 1980 and the response rate for stool collection was 67%. Bile acid analyses were performed on those cases that presented by 1990. It was decided in advance to examine the hypothesis separately for left- and right-sided bowel cancer because of known epidemiological differences between the two sites and to exclude the cases presenting within 2 years of the stool sample from the analyses because the cancer could have been present at recruitment and might have possibly affected faecal bile acid concentrations. Each case (n = 51 left-sided and 8 right-sided) was matched with three controls by age (within 5 years), sex, place of residence and time of providing the stool sample (within 3 months). Statistical analyses using conditional logistic regression showed no significant differences between the left-sided cases and controls for any of the concentrations of individual bile acids, total bile acid concentrations, faecal neutral steroids, percentage bacterial conversion and the ratio of lithocholic acid to deoxycholic acid concentrations. There was a statistically significant (P = 0.021) association of the presence of chenodeoxycholic acid (5/8 samples) in the right-sided cases compared with the controls (3/23), odds ratio 6.26 (95% confidence interval 1.19, 32.84). A high proportion of primary bile acids has also been found in other studies of patients with a genetic predisposition to proximal bowel cancer, however this pattern may also occur in low risk groups, such as Indian vegetarians, suggesting that they may predispose to right-sided bowel cancer only in the presence of other, as yet unknown factors. If bile acids are involved in the causation of large bowel cancer, they

  1. 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. PMID:25520305

  2. Bile Acids Trigger GLP-1 Release Predominantly by Accessing Basolaterally Located G Protein-Coupled Bile Acid Receptors.

    PubMed

    Brighton, Cheryl A; Rievaj, Juraj; Kuhre, Rune E; Glass, Leslie L; Schoonjans, Kristina; Holst, Jens J; Gribble, Fiona M; Reimann, Frank

    2015-11-01

    Bile acids are well-recognized stimuli of glucagon-like peptide-1 (GLP-1) secretion. This action has been attributed to activation of the G protein-coupled bile acid receptor GPBAR1 (TGR5), although other potential bile acid sensors include the nuclear farnesoid receptor and the apical sodium-coupled bile acid transporter ASBT. The aim of this study was to identify pathways important for GLP-1 release and to determine whether bile acids target their receptors on GLP-1-secreting L-cells from the apical or basolateral compartment. Using transgenic mice expressing fluorescent sensors specifically in L-cells, we observed that taurodeoxycholate (TDCA) and taurolithocholate (TLCA) increased intracellular cAMP and Ca(2+). In primary intestinal cultures, TDCA was a more potent GLP-1 secretagogue than taurocholate (TCA) and TLCA, correlating with a stronger Ca(2+) response to TDCA. Using small-volume Ussing chambers optimized for measuring GLP-1 secretion, we found that both a GPBAR1 agonist and TDCA stimulated GLP-1 release better when applied from the basolateral than from the luminal direction and that luminal TDCA was ineffective when intestinal tissue was pretreated with an ASBT inhibitor. ASBT inhibition had no significant effect in nonpolarized primary cultures. Studies in the perfused rat gut confirmed that vascularly administered TDCA was more effective than luminal TDCA. Intestinal primary cultures and Ussing chamber-mounted tissues from GPBAR1-knockout mice did not secrete GLP-1 in response to either TLCA or TDCA. We conclude that the action of bile acids on GLP-1 secretion is predominantly mediated by GPBAR1 located on the basolateral L-cell membrane, suggesting that stimulation of gut hormone secretion may include postabsorptive mechanisms. PMID:26280129

  3. Bile Acids Trigger GLP-1 Release Predominantly by Accessing Basolaterally Located G Protein–Coupled Bile Acid Receptors

    PubMed Central

    Brighton, Cheryl A.; Rievaj, Juraj; Kuhre, Rune E.; Glass, Leslie L.; Schoonjans, Kristina; Holst, Jens J.

    2015-01-01

    Bile acids are well-recognized stimuli of glucagon-like peptide-1 (GLP-1) secretion. This action has been attributed to activation of the G protein–coupled bile acid receptor GPBAR1 (TGR5), although other potential bile acid sensors include the nuclear farnesoid receptor and the apical sodium-coupled bile acid transporter ASBT. The aim of this study was to identify pathways important for GLP-1 release and to determine whether bile acids target their receptors on GLP-1–secreting L-cells from the apical or basolateral compartment. Using transgenic mice expressing fluorescent sensors specifically in L-cells, we observed that taurodeoxycholate (TDCA) and taurolithocholate (TLCA) increased intracellular cAMP and Ca2+. In primary intestinal cultures, TDCA was a more potent GLP-1 secretagogue than taurocholate (TCA) and TLCA, correlating with a stronger Ca2+ response to TDCA. Using small-volume Ussing chambers optimized for measuring GLP-1 secretion, we found that both a GPBAR1 agonist and TDCA stimulated GLP-1 release better when applied from the basolateral than from the luminal direction and that luminal TDCA was ineffective when intestinal tissue was pretreated with an ASBT inhibitor. ASBT inhibition had no significant effect in nonpolarized primary cultures. Studies in the perfused rat gut confirmed that vascularly administered TDCA was more effective than luminal TDCA. Intestinal primary cultures and Ussing chamber–mounted tissues from GPBAR1-knockout mice did not secrete GLP-1 in response to either TLCA or TDCA. We conclude that the action of bile acids on GLP-1 secretion is predominantly mediated by GPBAR1 located on the basolateral L-cell membrane, suggesting that stimulation of gut hormone secretion may include postabsorptive mechanisms. PMID:26280129

  4. The Conjugate Acid-Base Chart.

    ERIC Educational Resources Information Center

    Treptow, Richard S.

    1986-01-01

    Discusses the difficulties that beginning chemistry students have in understanding acid-base chemistry. Describes the use of conjugate acid-base charts in helping students visualize the conjugate relationship. Addresses chart construction, metal ions, buffers and pH titrations, and the organic functional groups and nonaqueous solvents. (TW)

  5. Enterobacteria modulate intestinal bile acid transport and homeostasis through apical sodium-dependent bile acid transporter (SLC10A2) expression.

    PubMed

    Miyata, Masaaki; Yamakawa, Hiroki; Hamatsu, Mayumi; Kuribayashi, Hideaki; Takamatsu, Yuki; Yamazoe, Yasushi

    2011-01-01

    In our study, ampicillin (AMP)-mediated decrease of enterobacteria caused increases in hepatic bile acid concentration through (at least in part) elevation of bile acid synthesis in C57BL/6N mice. We investigated the involvement of enterobacteria on intestinal bile acid absorption in AMP-treated mice in the present study. Fecal enterobacterial levels and fecal bile acid excretion rates were markedly decreased in mice treated with AMP (100 mg/kg) for 3 days, whereas bile acid concentrations in portal blood were significantly increased compared with those in mice treated with a vehicle. Ileal apical sodium-dependent bile acid transporter (SLC10A2) mRNA levels and ileal SLC10A2 protein levels in brush-border membranes were significantly increased compared with those in mice treated with the vehicle. In AMP-treated mice, total bile acid levels were increased, whereas levels of enterobacteria-biotransformed bile acid, taurodeoxycholic acid, and cholic acid were decreased in intestinal lumen. These phenomena were also observed in farnesoid X receptor-null mice treated with AMP for 3 days. Discontinuation of AMP administration after 3 days (vehicle administration for 4 days) increased levels of fecal enterobacteria, fecal bile acid excretion, and taurodeoxycholic acid and cholic acid in the intestinal lumen, whereas the discontinuation decreased ileal SLC10A2 expression and bile acid concentrations in the portal blood. Coadministration of taurodeoxycholic acid or cholic acid decreased ileal SLC10A2 expression in mice treated with AMP. These results suggest that enterobacteria-mediated bile acid biotransformation modulates intestinal bile acid transport and homeostasis through down-regulation of ileal SLC10A2 expression. PMID:20884752

  6. 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

  7. Semisynthetic bile acid FXR and TGR5 agonists: physicochemical properties, pharmacokinetics, and metabolism in the rat.

    PubMed

    Roda, Aldo; Pellicciari, Roberto; Gioiello, Antimo; Neri, Flavia; Camborata, Cecilia; Passeri, Daniela; De Franco, Francesca; Spinozzi, Silvia; Colliva, Carolina; Adorini, Luciano; Montagnani, Marco; Aldini, Rita

    2014-07-01

    We report on the relationship between the structure-pharmacokinetics, metabolism, and therapeutic activity of semisynthetic bile acid analogs, including 6α-ethyl-3α,7α-dihydroxy-5β-cholan-24-oic acid (a selective farnesoid X receptor [FXR] receptor agonist), 6α-ethyl-23(S)-methyl-3α,7α,12α-trihydroxy-5β-cholan-24-oic acid (a specific Takeda G protein-coupled receptor 5 [TGR5] receptor agonist), and 6α-ethyl-3α,7α-dihydroxy-24-nor-5β-cholan-23-sulfate (a dual FXR/TGR5 agonist). We measured the main physicochemical properties of these molecules, including ionization constants, water solubility, lipophilicity, detergency, and protein binding. Biliary secretion and metabolism and plasma and hepatic concentrations were evaluated by high-pressure liquid chromatography-electrospray-mass spectrometry/mass spectrometry in bile fistula rat and compared with natural analogs chenodeoxycholic, cholic acid, and taurochenodexycholic acid and intestinal bacteria metabolism was evaluated in terms of 7α-dehydroxylase substrate-specificity in anaerobic human stool culture. The semisynthetic derivatives detergency, measured in terms of their critical micellar concentration, was quite similar to the natural analogs. They were slightly more lipophilic than the corresponding natural analogs, evaluated by their 1-octanol water partition coefficient (log P), because of the ethyl group in 6 position, which makes these molecules very stable toward bacterial 7-dehydroxylation. The hepatic metabolism and biliary secretion were different: 6α-ethyl-3α,7α-dihydroxy-5β-cholan-24-oic acid, as chenodeoxycholic acid, was efficiently conjugated with taurine in the liver and, only in this form, promptly and efficiently secreted in bile. 6α-Ethyl-23(S)-methyl-3α,7α,12α-trihydroxy-5β-cholan-24-oic acid was poorly conjugated with taurine because of the steric hindrance of the methyl at C23(S) position metabolized to the C23(R) isomer and partly conjugated with taurine. Conversely, 6

  8. Bile acid derivatives as ligands of the farnesoid x receptor: molecular determinants for bile acid binding and receptor modulation.

    PubMed

    Gioiello, Antimo; Cerra, Bruno; Mostarda, Serena; Guercini, Chiara; Pellicciari, Roberto; Macchiarulo, Antonio

    2014-01-01

    Bile acids are a peculiar class of steroidal compounds that never cease to amaze. From being simple detergents with a primary role in aiding the absorption of fats and fat-soluble vitamins, bile acids are now widely considered as crucial hormones endowed with genomic and non-genomic functions that are mediated by their interaction with several proteins including the nuclear receptor Farnesoid X Receptor (FXR). Taking advantages of the peculiar properties of bile acids in interacting with the FXR receptor, several biliary derivatives have been synthesized and tested as FXR ligands. The availability of these compounds has contributed to characterize the receptor from a structural, patho-physiological and therapeutic standpoint. Among these, obeticholic acid is a first-in-class FXR agonist that is demonstrating hepatoprotective effects upon FXR activation in patients with liver diseases such as primary biliary cirrhosis and nonalcoholic steatohepatitis. This review provides an historical overview of the rationale behind the discovery of obeticholic acid and chemical tools generated to depict the molecular features and bio-pharmacological relevance of the FXR receptor, as well as to summarize structure-activity relationships of bile acid-based FXR ligands so far reported. PMID:25388535

  9. Colonic inflammation and secondary bile acids in alcoholic cirrhosis

    PubMed Central

    Kakiyama, Genta; Hylemon, Phillip B.; Zhou, Huiping; Pandak, William M.; Heuman, Douglas M.; Kang, Dae Joong; Takei, Hajime; Nittono, Hiroshi; Ridlon, Jason M.; Fuchs, Michael; Gurley, Emily C.; Wang, Yun; Liu, Runping; Sanyal, Arun J.; Gillevet, Patrick M.

    2014-01-01

    Alcohol abuse with/without cirrhosis is associated with an impaired gut barrier and inflammation. Gut microbiota can transform primary bile acids (BA) to secondary BAs, which can adversely impact the gut barrier. The purpose of this study was to define the effect of active alcohol intake on fecal BA levels and ileal and colonic inflammation in cirrhosis. Five age-matched groups {two noncirrhotic (control and drinkers) and three cirrhotic [nondrinkers/nonalcoholics (NAlc), abstinent alcoholic for >3 mo (AbsAlc), currently drinking (CurrAlc)]} were included. Fecal and serum BA analysis, serum endotoxin, and stool microbiota using pyrosequencing were performed. A subgroup of controls, NAlc, and CurrAlc underwent ileal and sigmoid colonic biopsies on which mRNA expression of TNF-α, IL-1β, IL-6, and cyclooxygenase-2 (Cox-2) were performed. One hundred three patients (19 healthy, 6 noncirrhotic drinkers, 10 CurrAlc, 38 AbsAlc, and 30 NAlc, age 56 yr, median MELD: 10.5) were included. Five each of healthy, CurrAlc, and NAlc underwent ileal/colonic biopsies. Endotoxin, serum-conjugated DCA and stool total BAs, and secondary-to-primary BA ratios were highest in current drinkers. On biopsies, a significantly higher mRNA expression of TNF-α, IL-1β, IL-6, and Cox-2 in colon but not ileum was seen in CurrAlc compared with NAlc and controls. Active alcohol use in cirrhosis is associated with a significant increase in the secondary BA formation compared with abstinent alcoholic cirrhotics and nonalcoholic cirrhotics. This increase in secondary BAs is associated with a significant increase in expression of inflammatory cytokines in colonic mucosa but not ileal mucosa, which may contribute to alcohol-induced gut barrier injury. PMID:24699327

  10. Cholesterol-lowering effect of rice bran protein containing bile acid-binding proteins.

    PubMed

    Wang, Jilite; Shimada, Masaya; Kato, Yukina; Kusada, Mio; Nagaoka, Satoshi

    2015-01-01

    Dietary plant protein is well known to reduce serum cholesterol levels. Rice bran is a by-product of rice milling and is a good source of protein. The present study examined whether feeding rats a high-cholesterol diet containing 10% rice bran protein (RBP) for 10 d affected cholesterol metabolism. Rats fed dietary RBP had lower serum total cholesterol levels and increased excretion of fecal steroids, such as cholesterol and bile acids, than those fed dietary casein. In vitro assays showed that RBP strongly bound to taurocholate, and inhibited the micellar solubility of cholesterol, compared with casein. Moreover, the bile acid-binding proteins of the RBP were eluted by a chromatographic column conjugated with cholic acid, and one of them was identified as hypothetical protein OsJ_13801 (NCBI accession No. EAZ29742) using MALDI-TOF mass spectrometry analysis. These results suggest that the hypocholesterolemic action of the RBP may be caused by the bile acid-binding proteins. PMID:25374002

  11. Carboxy-terminal mutations of bile acid CoA:N-acyltransferase alter activity and substrate specificity.

    PubMed

    Styles, Nathan A; Shonsey, Erin M; Falany, Josie L; Guidry, Amber L; Barnes, Stephen; Falany, Charles N

    2016-07-01

    Bile acid CoA:amino acid N-acyltransferase (BAAT) is the terminal enzyme in the synthesis of bile salts from cholesterol and catalyzes the conjugation of taurine or glycine to bile acid CoA thioesters to form bile acid N-acylamidates. BAAT has a dual localization to the cytosol and peroxisomes, possibly due to an inefficient carboxy-terminal peroxisomal targeting signal (PTS), -serine-glutamine-leucine (-SQL). Mutational analysis was used to define the role of the carboxy terminus in peroxisomal localization and kinetic activity. Amidation activity of BAAT and BAAT lacking the final two amino acids (AAs) (BAAT-S) were similar, whereas the activity of BAAT with a canonical PTS sequence (BAAT-SKL) was increased >2.5-fold. Kinetic analysis of BAAT and BAAT-SKL showed that BAAT-SKL had a lower Km for taurine and glycine as well as a greater Vmax There was no difference in the affinity for cholyl-CoA. In contrast to BAAT, BAAT-SKL forms bile acid N-acylamidates with β-alanine. BAAT-S immunoprecipitated when incubated with peroxisomal biogenesis factor 5 (Pex5) and rabbit anti-Pex5 antibodies; however, deleting the final 12 AAs prevented coimmunoprecipitation with Pex5, indicating the Pex5 interaction involves more than the -SQL sequence. These results indicate that even small changes in the carboxy terminus of BAAT can have significant effects on activity and substrate specificity. PMID:27230263

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

    SciTech Connect

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

    1990-04-01

    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 in 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.

  13. Medroxyprogesterone acetate- and ethinylestradiol-induced changes in biliary bile acids of the rat studied by high-performance liquid chromatography.

    PubMed

    Baker, P R; Vitale, G C; Siow, Y F

    1987-12-25

    The effects of subcutaneous administration (5 mg/kg per day) for seven days of medroxyprogesterone acetate (MPA) or 17 alpha-ethinylestradiol (EE) on bile flow, total bile acid output and individual biliary acids have been studied in adult male Wistar rats. Biliary bile acid composition was quantitated by a simple isocratic high-performance liquid chromatographic technique using a C18 reversed-phase radial compression column and refractive index detection. This method revealed that muricholic acids, analysed as taurine and glycine conjugates, constituted a higher proportion of biliary bile acids in the rat than previously observed with gas chromatographic techniques. Marked cholestasis was produced by EE while MPA had little effect on bile flow or total bile acid output. Despite this, both steroids significantly increased the proportion of taurine-conjugated muricholic acids relative to taurocholic acid, although the estrogen had the more pronounced effect. Further study of the hepatobiliary consequences of high doses of MPA would seem warranted in view of the important use of this progestogen for cancer therapy. PMID:2965158

  14. Structural stability and prebiotic properties of resistant starch type 3 increase bile acid turnover and lower secondary bile acid formation.

    PubMed

    Dongowski, Gerhard; Jacobasch, Gisela; Schmiedl, Detlef

    2005-11-16

    Microbial metabolism is essential in maintaining a healthy mucosa in the large bowel, preferentially through butyrate specific mechanisms. This system depends on starch supply. Two structurally different resistant starches type 3 (RS3) have been investigated with respect to their resistance to digestion, fermentability, and their effects on the composition and turnover of bile acids in rats. RSA (a mixture of retrograded maltodextrins and branched high molecular weight polymers), which is more resistant than RSB (a retrograded potato starch), increased the rate of fermentation accompanied by a decrease of pH in cecum, colon, and feces. Because they were bound to RS3, less bile acids were reabsorbed, resulting in a higher turnover through the large bowel. Because of the rise of volume, the bile acid level was unchanged and the formation of secondary bile acids was partly suppressed. The results proved a strong relation between RS3, short chain fatty acid production, and microflora. However, butyrate specific benefits are only achieved by an intake of RS3 that result in good fermentation properties, which depend on the kind of the resistant starch structures. PMID:16277431

  15. Expression of bile acid receptor TGR5 in gastric adenocarcinoma.

    PubMed

    Cao, Weibiao; Tian, Wei; Hong, Jie; Li, Dan; Tavares, Rosemarie; Noble, Lelia; Moss, Steven F; Resnick, Murray B

    2013-02-15

    Bile reflux is a risk factor in the development of intestinal metaplasia in the stomach and is believed to function as an initiator of gastric carcinogenesis. However, whether the G protein-coupled bile acid receptor TGR5 is expressed in this tumor is not known. In this study, we determined the expression of TGR5 in gastric adenocarcinoma and examined the role of TGR5 in cell proliferation. Strong TGR5 staining was present in 12% of cases of intestinal metaplasia but in no cases of normal gastric epithelium (P < 0.01). Moderate to strong TGR5 membranous and cytoplasmic staining was present in 52% of the intestinal but in only 25% of the diffuse subtype of adenocarcinomas (P < 0.001). Kaplan-Meier univariate survival analysis revealed that moderate to strong TGR5 staining was associated with decreased patient survival (P < 0.05). Treatment with taurodeoxycholic acid (TDCA, a bile acid) significantly increased thymidine incorporation in the AGS gastric adenocarcinoma cell line, suggesting that bile acids may increase cell proliferation. This increase was significantly decreased by knockdown of TGR5 with TGR5 small-interfering RNA (siRNA). In addition, overexpression of TGR5 significantly enhanced TDCA-induced increases in thymidine incorporation. TGR5 is coupled with G(q)α and Gα(i-3) proteins. TDCA-induced increase in thymidine incorporation was significantly decreased by knockdown of G(q)α and Gα(i-3) with their siRNAs. We conclude that TGR5 is overexpressed in most gastric intestinal-type adenocarcinomas, and moderate to strong TGR5 staining is associated with decreased patient survival in all gastric adenocarcinomas. Bile acids increase cell proliferation via activation of TGR5 receptors and G(q)α and Gα(i-3) proteins. PMID:23238937

  16. Bile acid transformations by Alcaligenes recti.

    PubMed

    Mazumder, I; Mahato, S B

    1993-02-01

    Metabolism of cholic acid, chenodeoxycholic acid, ursodeoxycholic acid, and deoxycholic acid by the grown cells of the bacterium Alcaligenes recti suspended in water was studied. Each isolated metabolite was characterized by the application of various spectroscopic methods. Cholic acid, chenodeoxycholic acid, ursodeoxycholic acid, and deoxycholic acid yielded methylated derivatives 3 alpha-methoxy-7 alpha, 12 alpha-dihydroxy-5 beta-cholanoic acid, 3 alpha-methoxy-7 alpha-hydroxy-5 beta-cholanoic acid, 3 alpha-methoxy-7 beta-hydroxy-5 beta-cholanoic acid, and 3 alpha-methoxy-12 alpha-hydroxy-5 beta-cholanoic acid, respectively. In addition, cholic acid furnished 7 alpha, 12 alpha-dihydroxy-3-oxochol-4-en-24-oic acid; chenodeoxycholic acid gave 7 alpha-hydroxy-3-oxo-5 beta-cholanoic acid and 7 alpha-hydroxy-3-oxochol-4-en-24-oic acid while ursodeoxycholic acid yielded 7 beta-hydroxy-3-oxochol-4-en-24-oic acid and 3-oxochola-4,6-dien-24-oic acid. The formation of various metabolites showed that two competitive enzymic reactions, i.e., selective methylation of the 3 alpha-hydroxy group and dehydrogenation in the A/B rings, were operative. The methylation process was found to be enzymic involving an S-adenosyl-L-methionine (AdoMet)-dependent methyl transferase, and this reaction appeared to be inhibitory to the process of degradation of the ring system. In the other reaction sequence, degradation of the ring system was initiated by dehydrogenation of the 3 alpha-hydroxy group. A 7 beta-dehydratase activity producing the delta 6 double bond was also noticeable in the metabolism of ursodeoxycholic acid. PMID:8484188

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

    SciTech Connect

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

    1989-03-01

    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 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.

  18. A liquid chromatography-tandem mass spectrometry-based method for the simultaneous determination of hydroxy sterols and bile acids.

    PubMed

    John, Clara; Werner, Philipp; Worthmann, Anna; Wegner, Katrin; Tödter, Klaus; Scheja, Ludger; Rohn, Sascha; Heeren, Joerg; Fischer, Markus

    2014-12-01

    Recently, hydroxy sterols and bile acids have gained growing interest as they are important regulators of energy homoeostasis and inflammation. The high number of different hydroxy sterols and bile acid species requires powerful analytical tools to quantify these structurally and chemically similar analytes. Here, we introduce a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method for rapid quantification of 34 sterols (hydroxy sterols, primary, secondary bile acids as well as their taurine and glycine conjugates). Chromatographic baseline separation of isomeric hydroxy sterols and bile acids is obtained using a rugged amide embedded C18 (polar embedded) stationary phase. The current method features a simple extraction protocol validated for blood plasma, urine, gall bladder, liver, feces, and adipose tissue avoiding solid phase extraction as well as derivatization procedures. The total extraction recovery for representative analytes ranged between 58-86% in plasma, 85% in urine, 79-92% in liver, 76-98% in adipose tissue, 93-104% in feces and 62-79% in gall bladder. The validation procedure demonstrated that the calibration curves were linear over the selected concentration ranges for 97% of the analytes, with calculated coefficients of determination (R2) of greater than 0.99. A feeding study in wild type mice with a standard chow and a cholesterol-enriched Western type diet illustrated that the protocol described here provides a powerful tool to simultaneously quantify cholesterol derivatives and bile acids in metabolically active tissues and to follow the enterohepatic circulation. PMID:25456597

  19. Ostα depletion protects liver from oral bile acid load

    PubMed Central

    Velazquez, Heino; Mennone, Albert; Ballatori, Nazzareno; Boyer, James L.

    2011-01-01

    Bile acid homeostasis is tightly maintained through interactions between the liver, intestine, and kidney. During cholestasis, the liver is incapable of properly clearing bile acids from the circulation, and alternative excretory pathways are utilized. In obstructive cholestasis, urinary elimination is often increased, and this pathway is further enhanced after bile duct ligation in mice that are genetically deficient in the heteromeric, basolateral organic solute transporter alpha-beta (Ostα-Ostβ). In this study, we examined renal and intestinal function in Ostα-deficient and wild-type mice in a model of bile acid overload. After 1% cholic acid feeding, Ostα-deficient mice had significantly lower serum ALT levels compared with wild-type controls, indicating partial protection from liver injury. Urinary clearance of bile acids, but not clearance of [3H]inulin, was significantly higher in cholic acid-fed Ostα-deficient mice compared with wild-type mice but was not sufficient to account for the protection. Fecal excretion of bile acids over the 5 days of cholic acid feeding was responsible for almost all of the bile acid loss in Ostα-deficient mice, suggesting that intestinal losses of bile acids accounted for the protection from liver injury. Thus fecal loss of bile acids after bile acid overload reduced the need for the kidney to filter and excrete the excess bile acids. In conclusion, Ostα-deficient mice efficiently eliminate excess bile acids via the feces. Inhibition of intestinal bile acid absorption might be an effective therapeutic target in early stages of cholestasis when bile acids are still excreted into bile. PMID:21719738

  20. Ostα depletion protects liver from oral bile acid load.

    PubMed

    Soroka, Carol J; Velazquez, Heino; Mennone, Albert; Ballatori, Nazzareno; Boyer, James L

    2011-09-01

    Bile acid homeostasis is tightly maintained through interactions between the liver, intestine, and kidney. During cholestasis, the liver is incapable of properly clearing bile acids from the circulation, and alternative excretory pathways are utilized. In obstructive cholestasis, urinary elimination is often increased, and this pathway is further enhanced after bile duct ligation in mice that are genetically deficient in the heteromeric, basolateral organic solute transporter alpha-beta (Ostα-Ostβ). In this study, we examined renal and intestinal function in Ostα-deficient and wild-type mice in a model of bile acid overload. After 1% cholic acid feeding, Ostα-deficient mice had significantly lower serum ALT levels compared with wild-type controls, indicating partial protection from liver injury. Urinary clearance of bile acids, but not clearance of [(3)H]inulin, was significantly higher in cholic acid-fed Ostα-deficient mice compared with wild-type mice but was not sufficient to account for the protection. Fecal excretion of bile acids over the 5 days of cholic acid feeding was responsible for almost all of the bile acid loss in Ostα-deficient mice, suggesting that intestinal losses of bile acids accounted for the protection from liver injury. Thus fecal loss of bile acids after bile acid overload reduced the need for the kidney to filter and excrete the excess bile acids. In conclusion, Ostα-deficient mice efficiently eliminate excess bile acids via the feces. Inhibition of intestinal bile acid absorption might be an effective therapeutic target in early stages of cholestasis when bile acids are still excreted into bile. PMID:21719738

  1. Deoxycholate Bile Acid Directed Synthesis of Branched Au Nanostructures for Near Infrared Photothermal Ablation

    PubMed Central

    Kim, Dong-Hyun; Larson, Andrew C.

    2015-01-01

    We report an approach for simple, reproducible and high-yield synthesis of branched GNPs directed by deoxycholate bile acid supramolecular aggregates in Au solution. A growth process involving stepwise trapping of the GNP seeds and Au ions in the deoxycholate bile acid solution yields multiple-branched GNPs. Upon NIR laser irradiation strong NIR absorption for branched GNPs induced photothermal-heating to destroy tumor cells. Subsequently, these branched GNPs were bio-functionalized with cRGD cell penetrating-targeting peptides for photothermal cancer treatment applications. Branched GNPs conjugated with cRGD peptides enhanced internalization of the branched GNPs in BxPC3 human pancreatic adenocarcinoma cells and effectively ablated BxPC3 cells when irradiated with a NIR laser (808 nm). Their potential use as photothermal transducing agents was demonstrated in in vivo settings using a pancreatic cancer xenograft model. The tumors were effectively ablated with cRGD-branched GNPs injection and laser exposure without any observation of tumor recurrence. This firstly reported method for deoxycholate bile acid directed synthesis of branched GNPs opens new possibilities for the production of strong NIR absorbing nanostructures for selective nanophotothermolisys of cancer cells and the further design of novel materials with customized spectral and structural properties for broader applications. PMID:25934288

  2. Bile acids and sphingosine-1-phosphate receptor 2 in hepatic lipid metabolism.

    PubMed

    Kwong, Eric; Li, Yunzhou; Hylemon, Phillip B; Zhou, Huiping

    2015-03-01

    The liver is the central organ involved in lipid metabolism. Dyslipidemia and its related disorders, including non-alcoholic fatty liver disease (NAFLD), obesity and other metabolic diseases, are of increasing public health concern due to their increasing prevalence in the population. Besides their well-characterized functions in cholesterol homoeostasis and nutrient absorption, bile acids are also important metabolic regulators and function as signaling hormones by activating specific nuclear receptors, G-protein coupled receptors, and multiple signaling pathways. Recent studies identified a new signaling pathway by which conjugated bile acids (CBA) activate the extracellular regulated protein kinases (ERK1/2) and protein kinase B (AKT) signaling pathway via sphingosine-1-phosphate receptor 2 (S1PR2). CBA-induced activation of S1PR2 is a key regulator of sphingosine kinase 2 (SphK2) and hepatic gene expression. This review focuses on recent findings related to the role of bile acids/S1PR2-mediated signaling pathways in regulating hepatic lipid metabolism. PMID:26579441

  3. Impact of Dry Solids and Bile Acid Concentrations on Bile Acid Binding Capacity of Extruded Oat Cereals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extruded breakfast cereals (EBC), processed from two oat lines, N979-5-2-4 (N979) and ‘Jim’, with beta-glucan concentrations of 8.7 and 4.9%, respectively, were used to determine the impact of dry solids (DS) and bile acid (BA) concentrations on in vitro BA binding efficiency. A full fractional fact...

  4. Influence of ethinyloestradiol propanolsulphonate on serum bile acids in healthy volunteers.

    PubMed

    Barth, Astrid; Klinger, Gottwalt; Rost, Michael

    2003-06-01

    The present work was done to clarify the relevance of altered serum bile acid (BA) profile in healthy women after the administration of the depot oestrogen ethinyloestradiol propanolsulphonate (EES). In the serum of 20 healthy women before and two times after oral EES application, 11 free and 14 taurine- and glycine-conjugated BA were analysed by HPLC with postcolumn derivatisation and fluorescence detection. EES significantly enhanced the total serum BA concentration and that of taurine-conjugated BAs, more pronounced the secondary BAs taurodeoxycholic, tauroursodeoxycholic and taurolithocholic acid. These secondary BAs are produced in the intestine by bacteria due to 7alpha-dehydroxylation of the primary BAs cholic and chenodeoxycholic acid. Because of unchanged free BAs, also produced by intestinal bacteria due to deconjugation, the results were interpreted as a sign of disturbed transport of BAs into the liver. Inhibition of the liver Na(+)-bile salt co-transporter (Ntcp) in the sinusoidal membrane by ethinyloestradiol, formed from the prodrug EES, may be responsible for the altered BA profile in serum. PMID:12877349

  5. Bile acid profiles by capillary electrophoresis in intrahepatic cholestasis of pregnancy.

    PubMed

    Castaño, Gustavo; Lucangioli, Silvia; Sookoian, Silvia; Mesquida, Marcelo; Lemberg, Abraham; Di Scala, Mirta; Franchi, Paula; Carducci, Clyde; Tripodi, Valeria

    2006-04-01

    ICP (intrahepatic cholestasis of pregnancy) is characterized by pruritus and biochemical cholestasis, including raised SBAs (serum bile acids) and, usually, elevated aminotransferases levels. However, AHP (asymptomatic hypercholanaemia of pregnancy) is defined as the presence of total SBA levels above the cut-off value (11 microM) in healthy pregnant women, thus elevation of total SBAs do not necessarily reflect an ICP condition. The aim of the present study was to describe clinical, obstetric, perinatal and biochemical findings, as well as the SBA profile, in pregnant women studied in the third trimester of pregnancy in order to define characteristic patterns of individual bile acids that enable women with ICP to be distinguished from AHP and healthy pregnancies. Free and conjugated ursodeoxycholic (UDCA), cholic (CA), lithocholic (LCA), deoxycholic (DCA) and chenodeoxycholic (CDCA) acids were evaluated by CE (capillary electrophoresis) in 41 patients (15 of them simultaneously by HPLC), in 30 healthy pregnant women and in 10 non-pregnant women. A highly significant correlation between CE and HPLC for total SBAs (r=0.990) and for individual SBAs was found. Normal pregnant women had higher total SBA levels than non-pregnant women (due to an increase in taurine-conjugated dihydroxy SBAs). Women with ICP had higher levels of total SBAs, the free/conjugated ratio, LCA, CA, CDCA and DCA than normal pregnant women. Newborns from women with ICP had lower birth weight and gestational age. Women with AHP had higher levels of conjugated dihydroxy SBAs than normocholanaemic patients, without any evidence of a clinical difference. In conclusion, the present study has shown a clear difference in SBA profiles between ICP and normal pregnancies (including AHP), involving a shift towards a characteristic hydrophobic composition in women with ICP. PMID:16356162

  6. A comparative study of the sulfation of bile acids and a bile alcohol by the Zebra danio (Danio rerio) and human cytosolic sulfotransferases (SULTs).

    PubMed

    Kurogi, Katsuhisa; Krasowski, Matthew D; Injeti, Elisha; Liu, Ming-Yih; Williams, Frederick E; Sakakibara, Yoichi; Suiko, Masahito; Liu, Ming-Cheh

    2011-11-01

    The current study was designed to examine the sulfation of bile acids and bile alcohols by the Zebra danio (Danio rerio) SULTs in comparison with human SULTs. A systematic analysis using the fifteen Zebra danio SULTs revealed that SULT3 ST2 and SULT3 ST3 were the major bile acid/alcohol-sulfating SULTs. Among the eleven human SULTs, only SULT2A1 was found to be capable of sulfating bile acids and bile alcohols. To further investigate the sulfation of bile acids and bile alcohols by the two Zebra danio SULT3 STs and the human SULT2A1, pH-dependence and kinetics of the sulfation of bile acids/alcohols were analyzed. pH-dependence experiments showed that the mechanisms underlying substrate recognition for the sulfation of lithocholic acid (a bile acid) and 5α-petromyzonol (a bile alcohol) differed between the human SULT2A1 and the Zebra danio SULT3 ST2 and ST3. Kinetic analysis indicated that both the two Zebra danio SULT3 STs preferred petromyzonol as substrate compared to bile acids. In contrast, the human SULT2A1 was more catalytically efficient toward lithocholic acid than petromyzonol. Collectively, the results imply that the Zebra danio and human SULTs have evolved to serve for the sulfation of, respectively, bile alcohols and bile acids, matching the cholanoid profile in these two vertebrate species. PMID:21839837

  7. A comparative study of the sulfation of bile acids and a bile alcohol by the Zebra danio (Danio rerio) and human cytosolic sulfotransferases (SULTs)

    PubMed Central

    Kurogi, Katsuhisa; Krasowski, Matthew D.; Injeti, Elisha; Liu, Ming-Yih; Williams, Frederick E.; Sakakibara, Yoichi; Suiko, Masahito; Liu, Ming-Cheh

    2012-01-01

    The current study was designed to examine the sulfation of bile acids and bile alcohols by the Zebra danio (Danio rerio) SULTs in comparison with human SULTs. A systematic analysis using the fifteen Zebra danio SULTs revealed that SULT3 ST2 and SULT3 ST3 were the major bile acid/alcohol-sulfating SULTs. Among the eleven human SULTs, only SULT2A1 was found to be capable of sulfating bile acids and bile alcohols. To further investigate the sulfation of bile acids and bile alcohols by the two Zebra danio SULT3 STs and the human SULT2A1, pH-dependence and kinetics of the sulfation of bile acids/alcohols were analyzed. pH-dependence experiments showed that the mechanisms underlying substrate recognition for the sulfation of lithocholic acid (a bile acid) and 5α-petromyzonol (a bile alcohol) differed between the human SULT2A1 and the Zebra danio SULT3 ST2 and ST3. Kinetic analysis indicated that both the two Zebra danio SULT3 STs preferred petromyzonol as substrate compared to bile acids. In contrast, the human SULT2A1 was more catalytically efficient toward lithocholic acid than petromyzonol. Collectively, the results imply that the Zebra danio and human SULTs have evolved to serve for the sulfation of, respectively, bile alcohols and bile acids, matching the cholanoid profile in these two vertebrate species. PMID:21839837

  8. Bile Acid Pool Dynamics in Progressive Familial Intrahepatic Cholestasis with Partial External Bile Diversion

    PubMed Central

    Jericho, Hilary Smith; Kaurs, Elizabeth; Boverhof, Renze; Knisely, Alex; Shneider, Benjamin L; Verkade, Henkjan J; Whitington, Peter F

    2015-01-01

    Objectives Partial external bile diversion (PEBD) is an established therapy for low-GGT Progressive Familial Intrahepatic Cholestasis (PFIC). This study sought to determine if the dynamics of the cholic acid (CA) and chenodeoxycholic acid (CDCA) pools in low-GGT-PFIC subjects with successful PEBD were equivalent to those achieved with successful liver transplantation (LTX). Methods The kinetics of CA and CDCA metabolism were measured by stable isotope dilution in plasma samples in 5 PEBD subjects all with intact canalicular BSEP expression and compared to low-GGT-PFIC subjects with successful LTX. Stomal loss of bile acids was measured in PEBD subjects. Results The fractional turnover rate for CA in the PEBD group ranged from 0.5 to 4.2 d−1 (LTX group, range 0.2 – 0.9 d−1, p = 0.076) and for CDCA from 0.7 to 4.5 d−1 (LTX group 0.3 – 0.4 d−1, p = 0.009). The CA and CDCA pool sizes were equivalent between groups; however pool composition in PEBD was somewhat more hydrophilic. The CA/CDCA ratio in PEBD ranged from 0.9 to 19.5, whereas in LTX it ranged from 0.5 to 2.6. Synthesis rates computed from isotope dilution correlated well with timed output for both CA: r2 = 0.760, p = 0.024 and CDCA: r2 = 0.690, p = 0.021. Conclusions PEBD results in bile acid fractional turnover rates greater than LTX, pool sizes equivalent to LTX and pool composition that is at least as hydrophilic as produced by LTX. PMID:25383786

  9. Enhanced antitumour drug delivery to cholangiocarcinoma through the apical sodium-dependent bile acid transporter (ASBT).

    PubMed

    Lozano, Elisa; Monte, Maria J; Briz, Oscar; Hernández-Hernández, Angel; Banales, Jesus M; Marin, Jose J G; Macias, Rocio I R

    2015-10-28

    Novel antitumour drugs, such as cationic tyrosine kinase inhibitors, are useful in many types of cancer but not in others, such as cholangiocarcinoma (CCA), where their uptake through specific membrane transporters, such as OCT1, is very poor. Here we have investigated the usefulness of targeting cytostatic bile acid derivatives to enhance the delivery of chemotherapy to tumours expressing the bile acid transporter ASBT and whether this is the case for CCA. The analysis of paired samples of CCA and adjacent non-tumour tissue collected from human (n=15) and rat (n=29) CCA revealed that ASBT expression was preserved. Moreover, ASBT was expressed, although at different levels, in human and rat CCA cell lines. Both cells in vitro and rat tumours in vivo were able to carry out efficient uptake of bile acid derivatives. Using Bamet-UD2 (cisplatin-ursodeoxycholate conjugate) as a model ASBT-targeted drug, in vitro and in vivo antiproliferative activity was evaluated. ASBT expression enhanced the sensitivity to Bamet-UD2, but not to cisplatin, in vitro. In nude mice, Bamet-UD2 (more than cisplatin) inhibited the growth of human colon adenocarcinoma tumours with induced stable expression of ASBT. As compared with cisplatin, administration of Bamet-UD2 to rats with CCA resulted in an efficient liver and tumour uptake but low exposure of extrahepatic tissues to the drug. Consequently, signs of liver/renal toxicity were absent in animals treated with Bamet-UD2. In conclusion, endogenous or induced ASBT expression may be useful in pharmacological strategies to treat enterohepatic tumours based on the use of cytostatic bile acid derivatives. PMID:26278512

  10. Potency of individual bile acids to regulate bile acid synthesis and transport genes in primary human hepatocyte cultures.

    PubMed

    Liu, Jie; Lu, Hong; Lu, Yuan-Fu; Lei, Xiaohong; Cui, Julia Yue; Ellis, Ewa; Strom, Stephen C; Klaassen, Curtis D

    2014-10-01

    Bile acids (BAs) are known to regulate their own homeostasis, but the potency of individual bile acids is not known. This study examined the effects of cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA) and ursodeoxycholic acid (UDCA) on expression of BA synthesis and transport genes in human primary hepatocyte cultures. Hepatocytes were treated with the individual BAs at 10, 30, and 100μM for 48 h, and RNA was extracted for real-time PCR analysis. For the classic pathway of BA synthesis, BAs except for UDCA markedly suppressed CYP7A1 (70-95%), the rate-limiting enzyme of bile acid synthesis, but only moderately (35%) down-regulated CYP8B1 at a high concentration of 100μM. BAs had minimal effects on mRNA of two enzymes of the alternative pathway of BA synthesis, namely CYP27A1 and CYP7B1. BAs increased the two major target genes of the farnesoid X receptor (FXR), namely the small heterodimer partner (SHP) by fourfold, and markedly induced fibroblast growth factor 19 (FGF19) over 100-fold. The BA uptake transporter Na(+)-taurocholate co-transporting polypeptide was unaffected, whereas the efflux transporter bile salt export pump was increased 15-fold and OSTα/β were increased 10-100-fold by BAs. The expression of the organic anion transporting polypeptide 1B3 (OATP1B3; sixfold), ATP-binding cassette (ABC) transporter G5 (ABCG5; sixfold), multidrug associated protein-2 (MRP2; twofold), and MRP3 (threefold) were also increased, albeit to lesser degrees. In general, CDCA was the most potent and effective BA in regulating these genes important for BA homeostasis, whereas DCA and CA were intermediate, LCA the least, and UDCA ineffective. PMID:25055961

  11. Bile acid profiles in intrahepatic cholestasis of pregnancy: is this the solution to the enigma of intrahepatic cholestasis of pregnancy?

    PubMed

    Sinakos, Emmanouil; Lindor, Keith D

    2010-03-01

    Intrahepatic cholestasis of pregnancy (ICP) is a rare pregnancy-related liver disease characterized by pruritus, abnormal liver function tests, and an increased risk of fetal complications. An increase in the levels of bile acids is considered to be the diagnostic hallmark of the disease. Ursodeoxycholic acid (UDCA) is currently the most effective therapy. Tribe et al. (this issue) hypothesized that measuring the longitudinal profiles of individual bile acids would provide further insight into the mechanisms of disease. They used a novel chromatography method, which allowed the simultaneous measurement of 15 serum bile acids between 16 weeks of pregnancy and 4 weeks post-partum. ICP was associated with a predominant rise in cholic acid conjugated with taurine and glycine from 24 weeks of pregnancy. UDCA treatment significantly reduced serum taurocholic and taurodeoxycholic acid concentrations. Finally, bile acid profiles were similar in normal pregnancy and pregnancy associated with pruritus gravidarum. The study by Tribe et al. (this issue) presents a significant contribution to the solution of this enigmatic disease by expanding our knowledge on the pathophysiology of ICP and proposing a convenient method for diagnosis and monitoring of this disorder. PMID:20203641

  12. Interactions between Diet, Bile Acid Metabolism, Gut Microbiota, and Inflammatory Bowel Diseases.

    PubMed

    Devkota, Suzanne; Chang, Eugene B

    2015-01-01

    The composite human gut microbiomes of Western populations have changed over the past century, brought on by new environmental triggers that often have a negative impact on human health. Diets high in saturated fats and refined sugars and low in fiber are leading candidates for these events and for triggering the increased prevalence of immune-mediated diseases like inflammatory bowel disease (IBD). Our studies have shown that consumption of a 'Western' diet high in saturated (milk-derived) fat (MF) or n-6 polyunsaturated (safflower oil) fat have similar effects on the structure of the colonic microbiome of wild-type and IL- 10(-/-) mice, characterized by increased Bacteroidetes and decreased Firmicutes. However, the MF diet uniquely promotes the expansion of an immunogenic sulfite-reducing pathobiont, Bilophila wadsworthia, a member of the Deltaproteobacteria and minor component of the gut microbiome. This bacterial bloom results from a MF diet-induced shift in hepatic conjugation of bile acids, from glycocholic to taurocholic (TC) acid, which is important for solubilizing the more hydrophobic MF diet. However, it is also responsible for delivery of taurine-derived sulfur to the distal bowel, promoting the assemblage of bile-tolerant microbes such as B. wadsworthia. The bloom of this species promotes a Th1-mediated immune response and the development of colitis in IL-10(-/-) mice. A similar bloom of B. wadsworthia is seen when IL-10(-/-) mice are fed a low-fat diet supplemented with TC. B. wadsworthia colonization of monoassociated germ-free IL-10(-/-) mice was dependent on the host consuming either a high-saturated MF diet or the gavage with TC. Together, these data provide a plausible explanation for the link between diseases such as IBD and dietary-mediated selection of gut microbial pathobionts in genetically susceptible hosts. With this knowledge, it may be possible to mitigate the bloom of these types of pathobionts by modifying the conjugation states of

  13. Regulation of human class I alcohol dehydrogenases by bile acids

    PubMed Central

    Langhi, Cédric; Pedraz-Cuesta, Elena; Haro, Diego; Marrero, Pedro F.; Rodríguez, Joan C.

    2013-01-01

    Class I alcohol dehydrogenases (ADH1s) are the rate-limiting enzymes for ethanol and vitamin A (retinol) metabolism in the liver. Because previous studies have shown that human ADH1 enzymes may participate in bile acid metabolism, we investigated whether the bile acid-activated nuclear receptor farnesoid X receptor (FXR) regulates ADH1 genes. In human hepatocytes, both the endogenous FXR ligand chenodeoxycholic acid and synthetic FXR-specific agonist GW4064 increased ADH1 mRNA, protein, and activity. Moreover, overexpression of a constitutively active form of FXR induced ADH1A and ADH1B expression, whereas silencing of FXR abolished the effects of FXR agonists on ADH1 expression and activity. Transient transfection studies and electrophoretic mobility shift assays revealed functional FXR response elements in the ADH1A and ADH1B proximal promoters, thus indicating that both genes are direct targets of FXR. These findings provide the first evidence for direct connection of bile acid signaling and alcohol metabolism. PMID:23772048

  14. Chemical Synthesis of Uncommon Natural Bile Acids: The 9α-Hydroxy Derivatives of Chenodeoxycholic and Lithocholic Acids.

    PubMed

    Iida, Takashi; Namegawa, Kazunari; Nakane, Naoya; Iida, Kyoko; Hofmann, Alan Frederick; Omura, Kaoru

    2016-09-01

    The chemical synthesis of the 9α-hydroxy derivatives of chenodeoxycholic and lithocholic acids is reported. For initiating the synthesis of the 9α-hydroxy derivative of chenodeoxycholic acid, cholic acid was used; for the synthesis of the 9α-hydroxy derivative of lithocholic acid, deoxycholic acid was used. The principal reactions involved were (1) decarbonylation of conjugated 12-oxo-Δ(9(11))-derivatives using in situ generated monochloroalane (AlH2Cl) prepared from LiAlH4 and AlCl3, (2) epoxidation of the deoxygenated Δ(9(11))-enes using m-chloroperbenzoic acid catalyzed by 4,4'-thiobis-(6-tert-butyl-3-methylphenol), (3) subsequent Markovnikov 9α-hydroxylation of the Δ(9(11))-enes with AlH2Cl, and (4) selective oxidation of the primary hydroxyl group at C-24 in the resulting 3α,9α,24-triol and 3α,7α,9α,24-tetrol to the corresponding C-24 carboxylic acids using sodium chlorite (NaClO2) in the presence of a catalytic amount of 2,2,6,6-tetramethylpiperidine 1-oxyl free radical (TEMPO) and sodium hypochlorite (NaOCl). The (1)H- and (13)C-NMR spectra are reported. The 3α,7α,9α-trihydroxy-5β-cholan-24-oic acid has been reported to be present in the bile of the Asian bear, and its 7-deoxy derivative is likely to be a bacterial metabolite. These bile acids are now available as authentic reference standards, permitting their identification in vertebrate bile acids. PMID:27319285

  15. Changes in bile acids, FGF-19 and sterol absorption in response to bile salt hydrolase active L. reuteri NCIMB 30242.

    PubMed

    Martoni, Christopher J; Labbé, Alain; Ganopolsky, Jorge G; Prakash, Satya; Jones, Mitchell L

    2015-01-01

    The size and composition of the circulating bile acid (BA) pool are important factors in regulating the human gut microbiota. Disrupted regulation of BA metabolism is implicated in several chronic diseases. Bile salt hydrolase (BSH)-active Lactobacillus reuteri NCIMB 30242, previously shown to decrease LDL-cholesterol and increase circulating BA, was investigated for its dose response effect on BA profile in a pilot clinical study. Ten otherwise healthy hypercholesterolemic adults, recruited from a clinical trial site in London, ON, were randomized to consume delayed release or standard release capsules containing L. reuteri NCIMB 30242 in escalating dose over 4 weeks. In another aspect, 4 healthy normocholesterolemic subjects with LDL-C below 3.4 mmol/l received delayed release L. reuteri NCIMB 30242 at a constant dose over 4 weeks. The primary outcome measure was the change in plasma BA profile over the intervention period. Additional outcomes included circulating fibroblast growth factor (FGF)-19, plant sterols and LDL-cholesterol as well as fecal microbiota and bsh gene presence. After one week of intervention subjects receiving delayed release L. reuteri NCIMB 30242 increased total BA by 1.13 ± 0.67 μmol/l (P = 0.02), conjugated BA by 0.67 ± 0.39 μmol/l (P = 0.02) and unconjugated BA by 0.46 ± 0.43 μmol/l (P = 0.07), which represented a greater than 2-fold change relative to baseline. Increases in BA were largely maintained post-week 1 and were generally correlated with FGF-19 and inversely correlated with plant sterols. This is the first clinical support showing that a BSH-active probiotic can significantly and rapidly influence BA metabolism and may prove useful in chronic diseases beyond hypercholesterolemia. PMID:25612224

  16. Changes in bile acids, FGF-19 and sterol absorption in response to bile salt hydrolase active L. reuteri NCIMB 30242

    PubMed Central

    Martoni, Christopher J; Labbé, Alain; Ganopolsky, Jorge G; Prakash, Satya; Jones, Mitchell L

    2015-01-01

    The size and composition of the circulating bile acid (BA) pool are important factors in regulating the human gut microbiota. Disrupted regulation of BA metabolism is implicated in several chronic diseases. Bile salt hydrolase (BSH)-active Lactobacillus reuteri NCIMB 30242, previously shown to decrease LDL-cholesterol and increase circulating BA, was investigated for its dose response effect on BA profile in a pilot clinical study. Ten otherwise healthy hypercholesterolemic adults, recruited from a clinical trial site in London, ON, were randomized to consume delayed release or standard release capsules containing L. reuteri NCIMB 30242 in escalating dose over 4 weeks. In another aspect, 4 healthy normocholesterolemic subjects with LDL-C below 3.4 mmol/l received delayed release L. reuteri NCIMB 30242 at a constant dose over 4 weeks. The primary outcome measure was the change in plasma BA profile over the intervention period. Additional outcomes included circulating fibroblast growth factor (FGF)-19, plant sterols and LDL-cholesterol as well as fecal microbiota and bsh gene presence. After one week of intervention subjects receiving delayed release L. reuteri NCIMB 30242 increased total BA by 1.13 ± 0.67 μmol/l (P = 0.02), conjugated BA by 0.67 ± 0.39 μmol/l (P = 0.02) and unconjugated BA by 0.46 ± 0.43 μmol/l (P = 0.07), which represented a greater than 2-fold change relative to baseline. Increases in BA were largely maintained post-week 1 and were generally correlated with FGF-19 and inversely correlated with plant sterols. This is the first clinical support showing that a BSH-active probiotic can significantly and rapidly influence BA metabolism and may prove useful in chronic diseases beyond hypercholesterolemia. PMID:25612224

  17. Synthesis and antifungal activity of bile acid-derived oxazoles.

    PubMed

    Fernández, Lucía R; Svetaz, Laura; Butassi, Estefanía; Zacchino, Susana A; Palermo, Jorge A; Sánchez, Marianela

    2016-04-01

    Peracetylated bile acids (1a-g) were used as starting materials for the preparation of fourteen new derivatives bearing an oxazole moiety in their side chain (6a-g, 8a-g). The key step for the synthetic path was a Dakin-West reaction followed by a Robinson-Gabriel cyclodehydration. A simpler model oxazole (12) was also synthesized. The antifungal activity of the new compounds (6a-g) as well as their starting bile acids (1a-g) was tested against Candida albicans. Compounds 6e and 6g showed the highest percentages of inhibition (63.84% and 61.40% at 250 μg/mL respectively). Deacetylation of compounds 6a-g, led to compounds 8a-g which showed lower activities than the acetylated derivatives. PMID:26827629

  18. Effect of ispaghula husk on the faecal output of bile acids in healthy volunteers.

    PubMed

    Chaplin, M F; Chaudhury, S; Dettmar, P W; Sykes, J; Shaw, A D; Davies, G J

    2000-04-01

    Faecal bile acids are associated with both colorectal cancer and serum cholesterol levels. We investigate whether dosing with ispaghula husk affects the faecal bile acid weights and concentrations in healthy adults. Sixteen healthy volunteers consumed 7.0 g/day ispaghula husk, containing 5.88 g/day Englyst-determinable dietary fibre, for the middle 8 weeks of a 12-week period. Stool samples were collected, analysed for faecal bile acids and their form and dry weight determined. Correlations between the faecal bile acids, the stool parameters and the dietary intake were tested. Ispaghula husk treatment significantly lowers faecal lithocholic and isolithocholic acids and the weighted ratio of lithocholic acids to deoxycholic acid. These effects revert towards their initial states at the end of the treatment period. These changes in the faecal bile acid profiles indicate a reduction in the hydrophobicity of the bile acids in the enterohepatic circulation. PMID:10822018

  19. Regulation of hepatic bile acid transporters Ntcp and Bsep expression.

    PubMed

    Cheng, Xingguo; Buckley, David; Klaassen, Curtis D

    2007-12-01

    Sodium-taurocholate cotransporting polypeptide (Ntcp) and bile salt export pump (Bsep) are two key transporters for hepatic bile acid uptake and excretion. Alterations in Ntcp and Bsep expression have been reported in pathophysiological conditions. In the present study, the effects of age, gender, and various chemicals on the regulation of these two transporters were characterized in mice. Ntcp and Bsep mRNA levels in mouse liver were low in the fetus, but increased to its highest expression at parturition. After birth, mouse Ntcp and Bsep mRNA decreased by more than 50%, and then gradually increased to adult levels by day 30. Expression of mouse Ntcp mRNA and protein exhibit higher levels in female than male livers. No gender difference exists in BSEP/Bsep expression in human and mouse livers. Hormone replacements conducted in gonadectomized, hypophysectomized, and lit/lit mice indicate that female-predominant Ntcp expression in mouse liver is due to the inhibitory effect of male-pattern GH secretion, but not sex hormones. Ntcp and Bsep expression are in general resistant to induction by a large battery of microsomal enzyme inducers. Administration of cholestyramine increased Ntcp, whereas chenodeoxycholic acid (CDCA) increased Bsep mRNA expression. In conclusion, mouse Ntcp and Bsep are regulated by age, gender, cholestyramine, and bile acid, but resistant to induction by most microsomal enzyme inducers. PMID:17897632

  20. Metabolic effects of intestinal absorption and enterohepatic cycling of bile acids.

    PubMed

    Ferrebee, Courtney B; Dawson, Paul A

    2015-03-01

    The classical functions of bile acids include acting as detergents to facilitate the digestion and absorption of nutrients in the gut. In addition, bile acids also act as signaling molecules to regulate glucose homeostasis, lipid metabolism and energy expenditure. The signaling potential of bile acids in compartments such as the systemic circulation is regulated in part by an efficient enterohepatic circulation that functions to conserve and channel the pool of bile acids within the intestinal and hepatobiliary compartments. Changes in hepatobiliary and intestinal bile acid transport can alter the composition, size, and distribution of the bile acid pool. These alterations in turn can have significant effects on bile acid signaling and their downstream metabolic targets. This review discusses recent advances in our understanding of the inter-relationship between the enterohepatic cycling of bile acids and the metabolic consequences of signaling via bile acid-activated receptors, such as farnesoid X nuclear receptor (FXR) and the G-protein-coupled bile acid receptor (TGR5). PMID:26579438

  1. Increased bile acids in enterohepatic circulation by short-term calorie restriction in male mice.

    PubMed

    Fu, Zidong Donna; Klaassen, Curtis D

    2013-12-15

    Previous studies showed glucose and insulin signaling can regulate bile acid (BA) metabolism during fasting or feeding. However, limited knowledge is available on the effect of calorie restriction (CR), a well-known anti-aging intervention, on BA homeostasis. To address this, the present study utilized a "dose-response" model of CR, where male C57BL/6 mice were fed 0, 15, 30, or 40% CR diets for one month, followed by BA profiling in various compartments of the enterohepatic circulation by UPLC-MS/MS technique. This study showed that 40% CR increased the BA pool size (162%) as well as total BAs in serum, gallbladder, and small intestinal contents. In addition, CR "dose-dependently" increased the concentrations of tauro-cholic acid (TCA) and many secondary BAs (produced by intestinal bacteria) in serum, such as tauro-deoxycholic acid (TDCA), DCA, lithocholic acid, ω-muricholic acid (ωMCA), and hyodeoxycholic acid. Notably, 40% CR increased TDCA by over 1000% (serum, liver, and gallbladder). Interestingly, 40% CR increased the proportion of 12α-hydroxylated BAs (CA and DCA), which correlated with improved glucose tolerance and lipid parameters. The CR-induced increase in BAs correlated with increased expression of BA-synthetic (Cyp7a1) and conjugating enzymes (BAL), and the ileal BA-binding protein (Ibabp). These results suggest that CR increases BAs in male mice possibly through orchestrated increases in BA synthesis and conjugation in liver as well as intracellular transport in ileum. PMID:24183703

  2. Evaluation of serum bile acid profiles as biomarkers of liver injury in rodents.

    PubMed

    Luo, Lina; Schomaker, Shelli; Houle, Christopher; Aubrecht, Jiri; Colangelo, Jennifer L

    2014-01-01

    Bile acids (BAs) have been studied as potential biomarkers of drug-induced liver injury. However, the relationship between levels of individual BAs and specific forms of liver injury remains to be fully understood. Thus, we set out to evaluate cholic acid (CA), glycocholic acid (GCA), and taurocholic acid (TCA) as potential biomarkers of liver injury in rodent toxicity studies. We have developed a sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) assay applicable to rat and mouse serum and evaluated levels of the individual BAs in comparison with the classical biomarkers of hepatotoxicity (alanine aminotransferase [ALT], aspartate aminotransferase [AST], glutamate dehydrogenase (GLDH), alkaline phosphatase, total bilirubin, gamma-glutamyl transferase, and total BAs) and histopathology findings in animals treated with model toxicants. The pattern of changes in the individual BAs varied with different forms of liver injury. Animals with histopathologic signs of hepatocellular necrosis showed increases in all 3 BAs tested, as well as increases in ALT, AST, GLDH, and total BAs. Animals with histopathologic signs of bile duct hyperplasia (BDH) displayed increases in only conjugated BAs (GCA and TCA), a pattern not observed with the other toxicants. Because BDH is detectable only via histopathology, our results indicate the potential diagnostic value of examining individual BAs levels in serum as biomarkers capable of differentiating specific forms of liver injury in rodent toxicity studies. PMID:24085190

  3. Method for the separation of the unconjugates and conjugates of chenodeoxycholic acid and deoxycholic acid by two-dimensional reversed-phase thin layer chromatography with methyl beta-cyclodextrin.

    PubMed

    Momose, T; Mure, M; Iida, T; Goto, J; Nambara, T

    1998-06-19

    A simple and efficient method for the separation of individual unconjugated bile acids and their glycine- and taurine-amidated, 3-sulfated, 3-glucosylated and 3-glucuronidated conjugates is described. The method involves the use of a two-dimensional (2D) reversed-phase (RP) high-performance thin-layer chromatographic (HPTLC) technique with methyl beta-cyclodextrin (Me-beta-CD). Five major unconjugated bile acids, chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), ursodeoxycholic acid and lithocholic acid, and their conjugates were examined as the solutes. A high degree of separation of individual bile acids in each homologous series was achieved on a RP-HPTLC plate by developing with aqueous methanol in the first dimension and the same solvent system containing Me-beta-CD in the second dimension. In particular, all of the six 'difficult-to-separate' pairs, unconjugated CDCA and DCA and their conjugated forms with glycine, taurine, sulfuric acid, D-glucose and D-glucuronic acid, were effectively resolved by adding Me-beta-CD in the aqueous mobile phases with the formers having larger mobilities than the latter. The application of this 2D inclusion RP-HPLC method to the separation of glycine-conjugated bile acids in human bile is also described. The present method would be useful for separating and characterizing these bile acids present in biological materials. PMID:9691303

  4. A biosynthetic pathway for a prominent class of microbiota-derived bile acids

    PubMed Central

    Devlin, A. Sloan; Fischbach, Michael A.

    2015-01-01

    The gut bile acid pool is millimolar in concentration, varies widely in composition among individuals, and is linked to metabolic disease and cancer. Although these molecules derive almost exclusively from the microbiota, remarkably little is known about which bacterial species and genes are responsible for their biosynthesis. Here, we report a biosynthetic pathway for the second most abundant class in the gut, iso (3β-hydroxy) bile acids, whose levels exceed 300 µM in some humans and are absent in others. We show, for the first time, that iso bile acids are produced by Ruminococcus gnavus, a far more abundant commensal than previously known producers; and that the iso bile acid pathway detoxifies deoxycholic acid, favoring the growth of the keystone genus Bacteroides. By revealing the biosynthetic genes for an abundant class of bile acids, our work sets the stage for predicting and rationally altering the composition of the bile acid pool. PMID:26192599

  5. 3alpha-6alpha-Dihydroxy-7alpha-fluoro-5beta-cholanoate (UPF-680), physicochemical and physiological properties of a new fluorinated bile acid that prevents 17alpha-ethynyl-estradiol-induced cholestasis in rats.

    PubMed

    Clerici, Carlo; Castellani, Danilo; Asciutti, Stefania; Pellicciari, Roberto; Setchell, Kenneth D R; O'Connell, Nancy C; Sadeghpour, Bahman; Camaioni, Emidio; Fiorucci, Stefano; Renga, Barbara; Nardi, Elisabetta; Sabatino, Giuseppe; Clementi, Mattia; Giuliano, Vittorio; Baldoni, Monia; Orlandi, Stefano; Mazzocchi, Alessandro; Morelli, Antonio; Morelli, Olivia

    2006-07-15

    3alpha-6alpha-Dihydroxy-7alpha-fluoro-5beta-cholanoate (UPF-680), the 7alpha-fluorine analog of hyodeoxycholic acid (HDCA), was synthesized to improve bioavailability and stability of ursodeoxycholic acid (UDCA). Acute rat biliary fistula and chronic cholestasis induced by 17alpha-ethynyl-estradiol (17EE) models were used to study and compare the effects of UPF-680 (dose range 0.6-6.0 micromol/kg min) with UDCA on bile flow, biliary bicarbonate (HCO(3)(-)), lipid output, biliary bile acid composition, hepatic enzymes and organic anion pumps. In acute infusion, UPF-680 increased bile flow in a dose-related manner, by up to 40.9%. Biliary HCO(3)(-) output was similarly increased. Changes were observed in phospholipid secretion only at the highest doses. Treatment with UDCA and UPF-680 reversed chronic cholestasis induced by 17EE; in this model, UDCA had no effect on bile flow in contrast to UPF-680, which significantly increased bile flow. With acute administration of UPF-680, the biliary bile acid pool became enriched with unconjugated and conjugated UPF-680 (71.7%) at the expense of endogenous cholic acid and muricholic isomers. With chronic administration of UPF-680 or UDCA, the main biliary bile acids were tauro conjugates, but modification of biliary bile acid pool was greater with UPF-680. UPF-680 increased the mRNA for cytochrome P450 7A1 (CYP7A1) and cytochrome P450 8B (CYP8B). Both UDCA and UPF-680 increased the mRNA for Na(+) taurocholate co-transporting polypeptide (NCTP). In conclusion, UPF-680 prevented 17EE-induced cholestasis and enriched the biliary bile acid pool with less detergent and cytotoxic bile acids. This novel fluorinated bile acid may have potential in the treatment of cholestatic liver disease. PMID:16487557

  6. 3{alpha}-6{alpha}-Dihydroxy-7{alpha}-fluoro-5{beta}-cholanoate (UPF-680), physicochemical and physiological properties of a new fluorinated bile acid that prevents 17{alpha}-ethynyl-estradiol-induced cholestasis in rats

    SciTech Connect

    Clerici, Carlo . E-mail: clerici@unipg.it; Castellani, Danilo; Asciutti, Stefania; Pellicciari, Roberto; Setchell, Kenneth D.R. |; O'Connell, Nancy C. |; Sadeghpour, Bahman; Camaioni, Emidio; Fiorucci, Stefano; Renga, Barbara; Nardi, Elisabetta; Sabatino, Giuseppe; Clementi, Mattia; Giuliano, Vittorio; Baldoni, Monia; Orlandi, Stefano; Mazzocchi, Alessandro; Morelli, Antonio; Morelli, Olivia

    2006-07-15

    3{alpha}-6{alpha}-Dihydroxy-7{alpha}-fluoro-5{beta}-cholanoate (UPF-680), the 7{alpha}-fluorine analog of hyodeoxycholic acid (HDCA), was synthesized to improve bioavailability and stability of ursodeoxycholic acid (UDCA). Acute rat biliary fistula and chronic cholestasis induced by 17{alpha}-ethynyl-estradiol (17EE) models were used to study and compare the effects of UPF-680 (dose range 0.6-6.0 {mu}mol/kg min) with UDCA on bile flow, biliary bicarbonate (HCO{sub 3} {sup -}), lipid output, biliary bile acid composition, hepatic enzymes and organic anion pumps. In acute infusion, UPF-680 increased bile flow in a dose-related manner, by up to 40.9%. Biliary HCO{sub 3} {sup -} output was similarly increased. Changes were observed in phospholipid secretion only at the highest doses. Treatment with UDCA and UPF-680 reversed chronic cholestasis induced by 17EE; in this model, UDCA had no effect on bile flow in contrast to UPF-680, which significantly increased bile flow. With acute administration of UPF-680, the biliary bile acid pool became enriched with unconjugated and conjugated UPF-680 (71.7%) at the expense of endogenous cholic acid and muricholic isomers. With chronic administration of UPF-680 or UDCA, the main biliary bile acids were tauro conjugates, but modification of biliary bile acid pool was greater with UPF-680. UPF-680 increased the mRNA for cytochrome P450 7A1 (CYP7A1) and cytochrome P450 8B (CYP8B). Both UDCA and UPF-680 increased the mRNA for Na{sup +} taurocholate co-transporting polypeptide (NCTP). In conclusion, UPF-680 prevented 17EE-induced cholestasis and enriched the biliary bile acid pool with less detergent and cytotoxic bile acids. This novel fluorinated bile acid may have potential in the treatment of cholestatic liver disease.

  7. Increased cell loss in the human jejunum induced by laxatives (ricinoleic acid, dioctyl sodium sulphosuccinate, magnesium sulphate, bile salts).

    PubMed Central

    Bretagne, J F; Vidon, N; L'Hirondel, C; Bernier, J J

    1981-01-01

    Two conjugated bile salts (10 mmol/l sodium glycocholate, 10 mmol/l sodium taurodeoxycholate) and three laxatives (30 mmol/l magnesium sulphate, 10 mmol/l ricinoleic acid, 2 mmol/l dioctyl sodium sulphosuccinate) were tested on seven subjects with no intestinal lesions in 14 experiments by intestinal perfusion of the jejunum. A 25 cm segment was studied. Each solution was perfused at the rate of 10 ml/min. Water and electrolyte fluxes, losses of deoxyribonucleic acid (DNA), and intestinal cell enzyme activity were measured in the fluids collected. All the laxatives and bile salts tested (except sodium glycocholate) induced water and electrolyte secretion, a rise in intraluminal DNA loss, and enzyme activity. It was possible to establish a significant correlation (p less than 0.001) between the amounts of water fluxes and DNA loss under the effect of dioctyl sodium sulphosuccinate and ricinoleic acid. PMID:6165655

  8. AKR1B7 Is Induced by the Farnesoid X Receptor and Metabolizes Bile Acids*

    PubMed Central

    Schmidt, Daniel R.; Schmidt, Samuel; Holmstrom, Sam R.; Makishima, Makoto; Yu, Ruth T.; Cummins, Carolyn L.; Mangelsdorf, David J.; Kliewer, Steven A.

    2011-01-01

    Although bile acids are crucial for the absorption of lipophilic nutrients in the intestine, they are cytotoxic at high concentrations and can cause liver damage and promote colorectal carcinogenesis. The farnesoid X receptor (FXR), which is activated by bile acids and abundantly expressed in enterohepatic tissues, plays a crucial role in maintaining bile acids at safe concentrations. Here, we show that FXR induces expression of Akr1b7 (aldo-keto reductase 1b7) in murine small intestine, colon, and liver by binding directly to a response element in the Akr1b7 promoter. We further show that AKR1B7 metabolizes 3-keto bile acids to 3β-hydroxy bile acids that are less toxic to cultured cells than their 3α-hydroxy precursors. These findings reveal a feed-forward, protective pathway operative in murine enterohepatic tissues wherein FXR induces AKR1B7 to detoxify bile acids. PMID:21081494

  9. Suppression of the HPA Axis During Cholestasis Can Be Attributed to Hypothalamic Bile Acid Signaling.

    PubMed

    McMillin, Matthew; Frampton, Gabriel; Quinn, Matthew; Divan, Ali; Grant, Stephanie; Patel, Nisha; Newell-Rogers, Karen; DeMorrow, Sharon

    2015-12-01

    Suppression of the hypothalamic-pituitary-adrenal (HPA) axis has been shown to occur during cholestatic liver injury. Furthermore, we have demonstrated that in a model of cholestasis, serum bile acids gain entry into the brain via a leaky blood brain barrier and that hypothalamic bile acid content is increased. Therefore, the aim of the current study was to determine the effects of bile acid signaling on the HPA axis. The data presented show that HPA axis suppression during cholestatic liver injury, specifically circulating corticosterone levels and hypothalamic corticotropin releasing hormone (CRH) expression, can be attenuated by administration of the bile acid sequestrant cholestyramine. Secondly, treatment of hypothalamic neurons with various bile acids suppressed CRH expression and secretion in vitro. However, in vivo HPA axis suppression was only evident after the central injection of the bile acids taurocholic acid or glycochenodeoxycholic acid but not the other bile acids studied. Furthermore, we demonstrate that taurocholic acid and glycochenodeoxycholic acid are exerting their effects on hypothalamic CRH expression after their uptake through the apical sodium-dependent bile acid transporter and subsequent activation of the glucocorticoid receptor. Taken together with previous studies, our data support the hypothesis that during cholestatic liver injury, bile acids gain entry into the brain, are transported into neurons through the apical sodium-dependent bile acid transporter and can activate the glucocorticoid receptor to suppress the HPA axis. These data also lend themselves to the broader hypothesis that bile acids may act as central modulators of hypothalamic peptides that may be altered during liver disease. PMID:26431088

  10. Bile acid promotes liver regeneration via farnesoid X receptor signaling pathways in rats.

    PubMed

    Ding, Long; Yang, Yu; Qu, Yikun; Yang, Ting; Wang, Kaifeng; Liu, Weixin; Xia, Weibin

    2015-06-01

    Bile acids, which are synthesized from cholesterol in the hepatocytes of the liver, are amphipathic molecules with a steroid backbone. Studies have shown that bile acid exhibits important effects on liver regeneration. However, the mechanism underlying these effects remains unclear. The aim of the present study was to investigate the effect of bile acid and the farnesoid X receptor (FXR) on hepatic regeneration and lipid metabolism. Rats were fed with 0.2% bile acid or glucose for 7 days and then subjected to a 50 or 70% hepatectomy. Hepatic regeneration rate, serum and liver levels of bile acid, and expression of FXR and Caveolin‑1, were detected at 24, 48 or 72 h following hepatectomy. The expression of proliferating cell nuclear antigen (PCNA) in the liver was measured using immunohistochemistry at the end of the study. Hepatocytes isolated from rats were treated with bile acid, glucose, FXR agonist and FXR antagonist, separately or in combination. Lipid metabolism, the expression of members of the FXR signaling pathway and energy metabolism‑related factors were measured using ELISA kits or western blotting. Bile acid significantly increased the hepatic regeneration rate and the expression of FXR, Caveolin‑1 and PCNA. Levels of total cholesterol and high density lipoprotein were increased in bile acid‑ or FXR agonist‑treated hepatocytes in vitro. Levels of triglyceride, low density lipoprotein and free fatty acid were decreased. In addition, bile acid and FXR agonists increased the expression of bile salt export pump and small heterodimer partner, and downregulated the expression of apical sodium‑dependent bile acid transporter, Na+/taurocholate cotransporting polypeptide and cholesterol 7α‑hydroxylase. These results suggested that physiological concentrations of bile acid may promote liver regeneration via FXR signaling pathways, and may be associated with energy metabolism. PMID:25634785

  11. Bile acid nephropathy in a bodybuilder abusing an anabolic androgenic steroid.

    PubMed

    Luciano, Randy L; Castano, Ekaterina; Moeckel, Gilbert; Perazella, Mark A

    2014-09-01

    Bile acid nephropathy, also known as cholemic nephrosis or nephropathy, is an entity that can be seen in patients with severe cholestatic liver disease. It typically is associated with acute kidney injury (AKI) with various forms of hepatic disease. Most often, patients with severe obstructive jaundice develop this lesion, which is thought to occur due to direct bile acid injury to tubular cells, as well as obstructing bile acid casts. Patients with end-stage liver disease also can develop AKI, in which case a more heterogeneous lesion occurs that includes hepatorenal syndrome and acute tubular injury/necrosis. In this circumstance, acute tubular injury develops from a combination of hemodynamic changes with some contribution from direct bile acid-related tubular toxicity and obstructive bile casts. We present a case of AKI due to bile acid nephropathy in a bodybuilder who developed severe cholestatic liver disease in the setting of anabolic androgenic steroid use. PMID:24953892

  12. Regulation of hepatic bile acid transporters Ntcp and Bsep expression

    PubMed Central

    Cheng, Xingguo; Buckley, David; Klaassen, Curtis D.

    2009-01-01

    Sodium-taurocholate cotransporting polypeptide (Ntcp) and bile salt export pump (Bsep) are two key transporters for hepatic bile acid uptake and excretion. Alterations in Ntcp and Bsep expression have been reported in pathophysiological conditions. In the present study, the effects of age, gender, and various chemicals on the regulation of these two transporters were characterized in mice. Ntcp and Bsep mRNA levels in mouse liver were low in the fetus, but increased to its highest expression at parturition. After birth, mouse Ntcp and Bsep mRNA decreased by more than 50%, and then gradually increased to adult levels by day 30. Expression of mouse Ntcp mRNA and protein exhibit higher levels in female than male livers, which is consistent with the trend of human NTCP mRNA expression between men and women. No gender difference exists in BSEP/Bsep expression in human and mouse livers. Hormone replacements conducted in gonadectomized, hypophysectomized, and lit/lit mice indicate that female-predominant Ntcp expression in mouse liver is due to the inhibitory effect of male-pattern GH secretion, but not sex hormones. Ntcp and Bsep expression are in general resistant to induction by a large battery of microsomal enzyme inducers. Administration of cholestyramine increased Ntcp, whereas chenodeoxycholic acid increased Bsep mRNA expression. In silico analysis indicates that female-predominant mouse and human Ntcp/NTCP expression may be due to GH. In conclusion, mouse Ntcp and Bsep are regulated by age, gender, cholestyramine, and bile acid, but resistant to induction by most microsomal enzyme inducers. PMID:17897632

  13. Bile acids as possible human carcinogens: new tricks from an old dog.

    PubMed

    Costarelli, Vassiliki

    2009-01-01

    Bile first attracted man's interest long ago. The actual tumour-promoting effects of a bile acid were reported in 1939 for deoxycholic acid. Ever since, much evidence has accumulated that supports an important role for bile acids as cancer promoters in humans through DNA damage and selection for apoptosis-resistant cells, both of which can lead to increased mutation rates. The evidence reviewed here indicates that, in humans, bile acids are likely to be implicated in the aetiology of a number of different important cancers in terms of morbidity and mortality, such as cancer of the colon, oesophagus, stomach, pancreas, gall bladder and cancer of the breast. PMID:19499433

  14. [Measurement of bile acid N-acetylglucosaminides in serum and urine of patients with chronic liver diseases during ursodeoxycholic acid treatment].

    PubMed

    Kimura, A; Nakamura, K; Makino, I

    1995-03-01

    Bile acid N-acetylglucosaminide (GlcNAc) was investigated in serum and urine of patients with chronic liver diseases during ursodeoxycholic acid (UDCA) treatment by HPLC. Bile acid N-acetylglucosaminide was not detected other than primary biliary cirrhosis in serum and urine. All of these N-acetyglucosaminide was ursodeoxycholic acid N-acetylglucosaminide (GlcNAc-UDCA). GlcNAc-UDCA excretion was 17.3 +/- 5.7 mg/day in PBC stage I, 12.1 +/- 5.4 mg/day in stage II, 39.1 +/- 20.8 mg/day in stage III. Among the GlcNAc fraction GlcNAc-UDCA-gly occupied greatest part followed by GlcNAc-UDCA-tau and non-amidated Glc-NAc-UDCA. GlcNAc-UDCA was 50.1% of total urinary bile acids excretion in PBC stage I, 32.5% in stage II, 20.5% in stage III. However, GlcNAc-UDCA was less than 2.5% of total serum bile acids in every stage. These results indicate that N-acetylglucosamine conjugation is one of the major pathway of UDCA in patient with primary biliary cirrhosis. PMID:7731091

  15. Probing the Binding Site of Bile Acids in TGR5.

    PubMed

    Macchiarulo, Antonio; Gioiello, Antimo; Thomas, Charles; Pols, Thijs W H; Nuti, Roberto; Ferrari, Cristina; Giacchè, Nicola; De Franco, Francesca; Pruzanski, Mark; Auwerx, Johan; Schoonjans, Kristina; Pellicciari, Roberto

    2013-12-12

    TGR5 is a G-protein-coupled receptor (GPCR) mediating cellular responses to bile acids (BAs). Although some efforts have been devoted to generate homology models of TGR5 and draw structure-activity relationships of BAs, none of these studies has hitherto described how BAs bind to TGR5. Here, we present an integrated computational, chemical, and biological approach that has been instrumental to determine the binding mode of BAs to TGR5. As a result, key residues have been identified that are involved in mediating the binding of BAs to the receptor. Collectively, these results provide new hints to design potent and selective TGR5 agonists. PMID:24900622

  16. Liquid crystal based biosensors for bile acid detection

    NASA Astrophysics Data System (ADS)

    He, Sihui; Liang, Wenlang; Tanner, Colleen; Fang, Jiyu; Wu, Shin-Tson

    2013-03-01

    The concentration level of bile acids is a useful indicator for early diagnosis of liver diseases. The prevalent measurement method in detecting bile acids is the chromatography coupled with mass spectrometry, which is precise yet expensive. Here we present a biosensor platform based on liquid crystal (LC) films for the detection of cholic acid (CA). This platform has the advantage of low cost, label-free, solution phase detection and simple analysis. In this platform, LC film of 4-Cyano-4'-pentylbiphenyl (5CB) was hosted by a copper grid supported with a polyimide-coated glass substrate. By immersing into sodium dodecyl sulfate (SDS) solution, the LC film was coated with SDS which induced a homeotropic anchoring of 5CB. Addition of CA introduced competitive adsorption between CA and SDS at the interface, triggering a transition from homeotropic to homogeneous anchoring. The detection limit can be tuned by changing the pH value of the solution from 12uM to 170uM.

  17. Mechanisms of triglyceride metabolism in patients with bile acid diarrhea.

    PubMed

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

    2016-08-14

    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

  18. 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

  19. Novel 3,4-seco bile acid diamides as selective anticancer proliferation and migration agents.

    PubMed

    Mao, Shi-Wei; Chen, Huang; Yu, Li-Fang; Lv, Fang; Xing, Ya-Jing; Liu, Ting; Xie, Jia; Tang, Jie; Yi, Zhengfang; Yang, Fan

    2016-10-21

    A series of new seco-A ring bile acid diamides were synthesized, and their antiproliferative activities against PC3M (prostate), HT29 (colon) and ES-2 (ovarian) cancer cell lines were investigated using SRB assays. Most synthesized compounds presented improved antiproliferative activities compared to the parent bile acids (IC50 > 80 μM), especially the piperazine conjugated compound 27 with IC50 values of 1.07, 4.58 and 3.86 μM against PC3M, HT29 and ES-2 cancer cell lines, respectively. In addition, all the tested compounds showed less cytotoxic activity on a noncancerous cell line (HAF), and the most active compound 27 exhibited the highest selectivity (Selectivity Index, SI(PC3M) = 26.3). Furthermore, 27 could also enhance G1 arrest in PC3M cell, revealed by cell cycle analysis, and increase anti-migration activity on PC3M cells, confirmed by transwell migration assay. PMID:27448915

  20. Systemic bile acid sensing by G protein-coupled bile acid receptor 1 (GPBAR1) promotes PYY and GLP-1 release

    PubMed Central

    Ullmer, C; Alvarez Sanchez, R; Sprecher, U; Raab, S; Mattei, P; Dehmlow, H; Sewing, S; Iglesias, A; Beauchamp, J; Conde-Knape, K

    2013-01-01

    Background and Purpose Nutrient sensing in the gut is believed to be accomplished through activation of GPCRs expressed on enteroendocrine cells. In particular, L-cells located predominantly in distal regions of the gut secrete glucagon-like peptide 1 (GLP-1) and peptide tyrosine-tyrosine (PYY) upon stimulation by nutrients and bile acids (BA). The study was designed to address the mechanism of hormone secretion in L-cells stimulated by the BA receptor G protein-coupled bile acid receptor 1 (GPBAR1). Experimental Approach A novel, selective, orally bioavailable, and potent GPBAR1 agonist, RO5527239, was synthesized in order to investigate L-cell secretion in vitro and in vivo in mice and monkey. In analogy to BA, RO5527239 was conjugated with taurine to reduce p.o. bioavailability yet retaining its potency. Using RO5527239 and tauro-RO5527239, the acute secretion effects on L-cells were addressed via different routes of administration. Key Results GPBAR1 signalling triggers the co-secretion of PYY and GLP-1, and leads to improved glucose tolerance. The strong correlation of plasma drug exposure and plasma PYY levels suggests activation of GPBAR1 from systemically accessible compartments. In contrast to the orally bioavailable agonist RO5527239, we show that tauro-RO5527239 triggers PYY release only when applied intravenously. Compared to mice, a slower and more sustained PYY secretion was observed in monkeys. Conclusion and Implications Selective GPBAR1 activation elicits a strong secretagogue effect on L-cells, which primarily requires systemic exposure. We suggest that GPBAR1 is a key player in the intestinal proximal-distal loop that mediates the early phase of nutrient-evoked L-cell secretion effects. PMID:23488746

  1. The Bile Acid Chenodeoxycholic Acid Increases Human Brown Adipose Tissue Activity.

    PubMed

    Broeders, Evie P M; Nascimento, Emmani B M; Havekes, Bas; Brans, Boudewijn; Roumans, Kay H M; Tailleux, Anne; Schaart, Gert; Kouach, Mostafa; Charton, Julie; Deprez, Benoit; Bouvy, Nicole D; Mottaghy, Felix; Staels, Bart; van Marken Lichtenbelt, Wouter D; Schrauwen, Patrick

    2015-09-01

    The interest in brown adipose tissue (BAT) as a target to combat metabolic disease has recently been renewed with the discovery of functional BAT in humans. In rodents, BAT can be activated by bile acids, which activate type 2 iodothyronine deiodinase (D2) in BAT via the G-coupled protein receptor TGR5, resulting in increased oxygen consumption and energy expenditure. Here we examined the effects of oral supplementation of the bile acid chenodeoxycholic acid (CDCA) on human BAT activity. Treatment of 12 healthy female subjects with CDCA for 2 days resulted in increased BAT activity. Whole-body energy expenditure was also increased upon CDCA treatment. In vitro treatment of primary human brown adipocytes derived with CDCA or specific TGR5 agonists increased mitochondrial uncoupling and D2 expression, an effect that was absent in human primary white adipocytes. These findings identify bile acids as a target to activate BAT in humans. PMID:26235421

  2. 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

  3. Recent Progress on Bile Acid Receptor Modulators for Treatment of Metabolic Diseases.

    PubMed

    Xu, Yanping

    2016-07-28

    Bile acids are steroid-derived molecules synthesized in the liver, secreted from hepatocytes into the bile canaliculi, and subsequently stored in the gall bladder. During the feeding, bile flows into the duodenum, where it contributes to the solubilization and digestion of lipid-soluble nutrients. After a meal, bile-acid levels increase in the intestine, liver, and also in the systemic circulation. Therefore, serum bile-acid levels serve as an important sensing mechanism for nutrient and energy. Recent studies have described bile acids as versatile signaling molecules endowed with systemic endocrine functions. Bile acids are ligands for G-protein coupled receptors (GPCRs) such as TGR5 (also known as GPBAR1, M-BAR, and BG37) and nuclear hormone receptors including farnesoid X receptor (FXR; also known as NR1H4). Acting through these diverse signaling pathways, bile acids regulate triglyceride, cholesterol, glucose homeostasis, and energy expenditure. These bile-acid-controlled signaling pathways have become the source of promising novel drug targets to treat common metabolic and hepatic diseases. PMID:26878262

  4. 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

  5. Effects of cholecystectomy on the kinetics of primary and secondary bile acids.

    PubMed Central

    Berr, F; Stellaard, F; Pratschke, E; Paumgartner, G

    1989-01-01

    Removal of the gallbladder is thought to increase formation and pool size of secondary bile acids, mainly deoxycholic acid (DCA), by increased exposure of primary bile acids (cholic acid [CA], chenodeoxycholic acid [CDCA]) to bacterial dehydroxylation in the intestine. We have tested this hypothesis by simultaneous determination of pool size and turnover of DCA, CA, and CDCA in nine women before and at various intervals after removal of a functioning gallbladder. An isotope dilution technique using marker bile acids labeled with stable isotopes (2H4-DCA, 13C-CA, 13C-CDCA) was used. After cholecystectomy, concentration and output of bile acids relative to bilirubin increased (P less than 0.02) in fasting duodenal bile and cholesterol saturation decreased by 27% (P less than 0.05) consistent with enhanced enterohepatic cycling of bile acids. Three months after removal of the gallbladder bile acid kinetics were in a new steady state: pool size and turnover of CDCA were unchanged. Synthesis of CA, the precursor of DCA, was diminished by 37% (P = 0.05), probably resulting from feedback inhibition by continuous transhepatic flux of bile acids. The fraction of CA transferred after 7 alpha-dehydroxylation to the DCA pool increased from 46 +/- 16 to 66 +/- 32% (P less than 0.05). However, this enhanced transfer did not lead to increased input or size of the DCA pool, because synthesis of the precursor CA had decreased. PMID:2708522

  6. Bile acids regulate intestinal cell proliferation by modulating EGFR and FXR signaling.

    PubMed

    Dossa, Avafia Y; Escobar, Oswaldo; Golden, Jamie; Frey, Mark R; Ford, Henri R; Gayer, Christopher P

    2016-01-15

    Bile acids (BAs) are synthesized in the liver and secreted into the intestine. In the lumen, enteric bacteria metabolize BAs from conjugated, primary forms into more toxic unconjugated, secondary metabolites. Secondary BAs can be injurious to the intestine and may contribute to disease. The epidermal growth factor receptor (EGFR) and the nuclear farnesoid X receptor (FXR) are known to interact with BAs. In this study we examined the effects of BAs on intestinal epithelial cell proliferation and investigated the possible roles for EGFR and FXR in these effects. We report that taurine-conjugated cholic acid (TCA) induced proliferation, while its unconjugated secondary counterpart deoxycholic acid (DCA) inhibited proliferation. TCA stimulated phosphorylation of Src, EGFR, and ERK 1/2. Pharmacological blockade of any of these pathways or genetic ablation of EGFR abrogated TCA-stimulated proliferation. Interestingly, Src or EGFR inhibitors eliminated TCA-induced phosphorylation of both molecules, suggesting that their activation is interdependent. In contrast to TCA, DCA exposure diminished EGFR phosphorylation, and pharmacological or siRNA blockade of FXR abolished DCA-induced inhibition of proliferation. Taken together, these results suggest that TCA induces intestinal cell proliferation via Src, EGFR, and ERK activation. In contrast, DCA inhibits proliferation via an FXR-dependent mechanism that may include downstream inactivation of the EGFR/Src/ERK pathway. Since elevated secondary BA levels are the result of specific bacterial modification, this may provide a mechanism through which an altered microbiota contributes to normal or abnormal intestinal epithelial cell proliferation. PMID:26608185

  7. A novel varanic acid epimer--(24R,25S)-3α,7α,12α,24-tetrahydroxy-5β-cholestan-27-oic acid--is a major biliary bile acid in two varanid lizards and the Gila monster.

    PubMed

    Hagey, Lee R; Ogawa, Shoujiro; Kato, Narimi; Satoh née Okihara, Rika; Une, Mizuho; Mitamura, Kuniko; Ikegawa, Shigeo; Hofmann, Alan F; Iida, Takashi

    2012-11-01

    A key intermediate in the biosynthetic pathway by which C(24) bile acids are formed from cholesterol has long been considered to be varanic acid, (24ξ,25ξ)-3α,7α,12α-24-tetrahydroxy-5β-cholestan-27-oic acid. The (24R,25R)-epimer of this tetrahydroxy bile acid, in the form of its taurine N-acyl amidate, was thought to be the major biliary bile acid in lizards of the family Varanidae. We report here that a major biliary bile acid of three lizard species - the Komodo dragon (Varanus komodoensis), Gray's monitor (Varanus olivaceus), and the Gila monster (Heloderma suspectum) - is a novel epimer of varanic acid. The epimer was shown to be (24R,25S)-3α,7α,12α,24-tetrahydroxy-5β-cholestan-27-oic acid (present in bile as its taurine conjugate). The structure was established by mass spectroscopy and by (1)H and (13)C nuclear magnetic spectroscopy, as well as by synthesis of the compound. PMID:22986074

  8. Suppression of Autophagic Flux by Bile Acids in Hepatocytes

    PubMed Central

    Kong, Bo; Guo, Grace; Ding, Wen-Xing

    2014-01-01

    Retention of bile acids (BAs) in the liver during cholestasis plays an important role in the development of cholestatic liver injury. Several studies have reported that high concentrations of certain BAs induce cell death and inflammatory response in the liver, and BAs may promote liver tumorigenesis. Macroautophagy (hereafter referred to as autophagy) is a lysosomal degradation process that regulates organelle and protein homeostasis and serves as a cell survival mechanism under a variety of stress conditions. However, it is not known if BAs modulate autophagy in hepatocytes. In the present study, we determined autophagic flux in livers of farnesoid X receptor (FXR) knockout (KO) mice that have increased concentrations of hepatic BAs and in primary cultured mouse hepatocytes treated with BAs. The results showed that autophagic flux was impaired in livers of FXR KO mice and in BA-treated primary mouse hepatocytes. Mechanistically, BAs did not affect the activities of cathepsin or the proteasome, but impaired autophagosomal-lysosomal fusion likely due to reduction of Rab7 protein expression and targeting to autophagosomes. In conclusion, BAs suppress autophagic flux in hepatocytes by impairing autophagosomal-lysosomal fusion, which may be implicated in bile acid-induced liver tumor promotion observed in FXR KO mice. PMID:24189133

  9. Bile Acid Alters Male Mouse Fertility in Metabolic Syndrome Context

    PubMed Central

    Baptissart, Marine; De Haze, Angélique; Vaz, Frederic; Kulik, Wim; Damon-Soubeyrand, Christelle; Baron, Silvère; Caira, Françoise; Volle, David H.

    2015-01-01

    Bile acids have recently been demonstrated as molecules with endocrine activities controlling several physiological functions such as immunity and glucose homeostases. They act mainly through two receptors, the nuclear receptor Farnesol-X-Receptor alpha (FXRα) and the G-protein coupled receptor (TGR5). These recent studies have led to the idea that molecules derived from bile acids (BAs) and targeting their receptors must be good targets for treatment of metabolic diseases such as obesity or diabetes. Thus it might be important to decipher the potential long term impact of such treatment on different physiological functions. Indeed, BAs have recently been demonstrated to alter male fertility. Here we demonstrate that in mice with overweight induced by high fat diet, BA exposure leads to increased rate of male infertility. This is associated with the altered germ cell proliferation, default of testicular endocrine function and abnormalities in cell-cell interaction within the seminiferous epithelium. Even if the identification of the exact molecular mechanisms will need more studies, the present results suggest that both FXRα and TGR5 might be involved. We believed that this work is of particular interest regarding the potential consequences on future approaches for the treatment of metabolic diseases. PMID:26439743

  10. Inflammatory bowel disease alters intestinal bile acid transporter expression.

    PubMed

    Jahnel, Jörg; Fickert, Peter; Hauer, Almuthe C; Högenauer, Christoph; Avian, Alexander; Trauner, Michael

    2014-09-01

    The enterohepatic circulation of bile acids (BAs) critically depends on absorption of BA in the terminal ileum and colon, which can be affected by inflammatory bowel disease (IBD). Diarrhea in IBD is believed to result in part from BA malabsorption (BAM). We explored whether IBD alters mRNA expression of key intestinal BA transporters, BA detoxifying systems, and nuclear receptors that regulate BA transport and detoxification. Using real-time polymerase chain reaction, mucosal biopsy specimens from the terminal ileum in Crohn's disease (CD) patients and from the descending colon in ulcerative colitis (UC) patients were assessed for mRNA expression. Levels were compared with healthy controls. The main ileal BA uptake transporter, the apical sodium dependent bile acid transporter, was downregulated in active CD and UC and in CD in remission. Other significant changes such as repression of breast cancer-related protein and sulphotransferase 2A1 were seen only during active disease. In UC, pancolitis (but not exclusively left-sided colitis) was associated with altered expression of major BA transporters [multidrug resistance-associated protein 3 (MRP3), MRP4, multidrug resistance gene 1, organic solute transporter α/β] and nuclear receptors (pregnane X receptor, vitamin D receptor) in the descending colon. UC pancolitis leads to broad changes and CD ileitis to selective changes in intestinal BA transporter expression. Early medical manipulation of intestinal BA transporters may help prevent BAM. PMID:24965812

  11. Influence of dietary retrograded starch on the metabolism of neutral steroids and bile acids in rats.

    PubMed

    Verbeek, M J; De Deckere, E A; Tijburg, L B; Van Amelsvoort, J M; Beynen, A C

    1995-12-01

    Diets enriched in retrograded amylose (RS3) have been shown to lower serum cholesterol concentrations in rats. The possibility was tested that this hypocholesterolaemic effect of RS3 is caused by an increase in excretion of neutral steroids and/or bile acids. Six groups of ten rats were fed on purified diets containing either 12 or 140 g RS3/kg solid ingredients with and without added cholesterol (5g/kg). Low-RS3 diets, with and without added cholesterol, to which the bile-acid-binding resin cholestyramine (20 g/kg) was added, were used as reference. The high-RS3 diets v. the low-RS3 diets tended to reduce the increase in the total serum cholesterol concentration during the course of the experiment (P = 0.067), decreased serum triacylglycerol concentrations, raised total neutral steroids and total bile acids in caecal contents and faecal excretion of total bile acids, but lowered faecal excretion of neutral steroids. In addition, the serum concentration of total 3 alpha-bile acids was markedly raised by the high-RS3 diets. The high-RS3 diets raised the faecal excretion of lithocholic and muricholic acids, but lowered that of hyodeoxycholic acid, and increased the caecal amounts of lithocholic, ursodeoxycholic, beta-muricholic and omega-muricholic acids. Apart from the stimulation of faecal bile acids excretion, the effects of cholestyramine on bile acid metabolism differed at various points from those of RS3. Cholesterol feeding had predictable effects on cholesterol metabolism and led to greater elevating effects of RS3 on the faecal and caecal amounts of muricholic acids. The results suggest that the serum-cholesterol-lowering effect of high-RS3 diets may be explained by an increased influx of neutral steroids and bile acids into the caecum, and increased faecal excretion of bile acids, and/or by an altered intestinal bile acid profile. PMID:8562568

  12. The metabolism of primary, 7-oxo, and 7 beta-hydroxy bile acids by Clostridium absonum.

    PubMed

    Sutherland, J D; Macdonald, I A

    1982-07-01

    Clostridium absonum was shown to metabolize primary bile acids to give rise to both 7-oxo bile acids and 7 beta-hydroxy (urso) bile acids. At relatively low redox potential (Eh) values, high yields of urso bile acids were achieved (60-75%). If, however, the Eh value of the culture was allowed to rise above approximately -100 mv, the 7-oxo bile acid would tend to predominate (more than 75%) and the "death phase" was accelerated. Growth of C. absonum in sterile graduated cylinders instead of in conventional Erlenmeyer flasks was effective in delaying the rise in Eh value with time (which appears largely due to diffusion of atmospheric oxygen into the medium) and in preserving a higher viable count of organisms. It is proposed that the formation of excess amounts of 7-oxo bile acid is a manifestation of oxygen toxicity and that it could be mediated by an increasing intracellular NADP:NADPH ratio. Additionally, the reaction: primary bile acid in equilibrium oxo bile acid in equilibrium urso bile acid was shown to be partially reversible. When the organisms were grown with [24-(14)C]chenodeoxycholic, -cholic, or -7-keto-lithocholic acid, this reaction could be clearly demonstrated. The addition of an equimolar concentration of deoxycholic acid (which itself is not metabolized) effectively enhanced the rate of bioconversion of cholate and 7-keto-lithocholic, but not chenodeoxycholate (whose rate of bioconversion was the fastest of the three). When the organisms were grown with urso bile acids (ursocholic or ursodeoxycholic) or with 7-keto-deoxycholic acid, very little metabolism occurred unless deoxycholic acid was added which induced formation of primary and keto bile acids. In all cases, formation of oxo bile acid from primary or urso bile acid occurred as the Eh value of the medium rose with time and could thus be delayed by the use of a cylinder instead of a flask for growing the culture. These results were rationalized by demonstrating that induction of 7 alpha- and

  13. Delta 4-3-oxosteroid 5 beta-reductase deficiency described in identical twins with neonatal hepatitis. A new inborn error in bile acid synthesis.

    PubMed Central

    Setchell, K D; Suchy, F J; Welsh, M B; Zimmer-Nechemias, L; Heubi, J; Balistreri, W F

    1988-01-01

    A new inborn error in bile acid synthesis, manifest in identical infant twins as severe intrahepatic cholestasis, is described involving the delta 4-3-oxosteroid 5 beta-reductase catalyzed conversion of the key intermediates, 7 alpha-hydroxy-4-cholesten-3-one and 7 alpha,12 alpha-dihydroxy-4-cholesten-3-one for chenodeoxycholic and cholic acid synthesis, to the respective 3 alpha-hydroxy-5 beta (H) products. This defect was detected by fast atom bombardment ionization-mass spectrometry from an elevated excretion and predominance of taurine conjugated unsaturated hydroxy-oxo-bile acids. Gas chromatography-mass spectrometry confirmed these to be 7 alpha-hydroxy-3-oxo-4-cholenoic and 7 alpha,12 alpha-dihydroxy-3-oxo-4-cholenoic acids (75-92% of total). Fasting serum bile acid concentrations were greater than 37 mumol/liter; chenodeoxycholic acid was the major bile acid, but significant amounts of allo(5 alpha-H)-bile acids (approximately 30%) were present. Biliary bile acid concentration was less than 2 mumol/liter and consisted of chenodeoxycholic, allo-chenodeoxycholic, and allo-cholic acids. These biochemical findings, which were identical in both infants, indicate a defect in bile acid synthesis involving the conversion of the delta 4-3-oxo-C27 intermediates into the corresponding 3 alpha-hydroxy-5 beta(H)-structures, a reaction that is catalyzed by a delta 4-3-oxosteroid-5 beta reductase enzyme. This defect resulted in markedly reduced primary bile acid synthesis and concomitant accumulation of delta 4-3-oxo-and allo-bile acids. These findings indicate a pathway in bile acid synthesis whereby side chain oxidation can occur despite incomplete alterations to the steroid nucleus, and lend support for an active delta 4-3-oxosteroid 5 alpha-reductase catalyzing the conversion of the delta 4-3-oxosteroid intermediates to the respective 3 alpha-hydroxy-5 alpha(H)-structures. PMID:3198770

  14. Serum Bile Acids Are Associated with Pathological Progression of Hepatitis B-Induced Cirrhosis.

    PubMed

    Wang, Xiaoning; Xie, Guoxiang; Zhao, Aihua; Zheng, Xiaojiao; Huang, Fengjie; Wang, Yixing; Yao, Chun; Jia, Wei; Liu, Ping

    2016-04-01

    Recent metabonomic studies have identified an important role of bile acids in patients with liver cirrhosis. Serum bile acids, such as glycocholate (GCA), glycochenodeoxycholate (GCDCA), taurocholate (TCA), and taurochenodeoxycholate (TCDCA), increased significantly in liver cirrhosis patients. Our recently published urinary metabonomic study showed that glycocholate 3-glucuronide, taurohyocholate, TCA, glycolithocholate 3-sulfate, and glycoursodeoxycholate (GUDCA) were markedly increased in hepatitis B-induced cirrhotic patients (n = 63) compared with healthy controls (n = 31). The urinary levels of GUDCA were able to differentiate among three stages of cirrhotic patients with Child-Pugh (CP) score A, B, and C. In this study, we recruited two new cohorts of patients with hepatitis-B-induced cirrhosis and healthy control subjects and quantitatively profiled their serum bile acids using ultra-performance liquid chromatography triple quadrupole mass spectrometry. Serum bile acid profile and corresponding differential bile acids were characterized, in addition to the blood routine, liver, and renal function tests. The alterations of bile acids contributing to the intergroup variation between healthy controls and cirrhotic patients and among pathological stages of CP grade A, B and C were also investigated. Five bile acids, GCA, GCDCA, TCA, TCDCA, and GUDCA, were significantly altered among different stages of liver cirrhosis (n = 85), which was validated with an independent cohort of cirrhotic patients (n = 53). Our results show that dynamic alteration of serum bile acids is indicative of an exacerbated liver function, highlighting their potential as biomarkers for staging the liver cirrhosis and monitoring its progression. PMID:25964117

  15. Intestinal bile acid sensing is linked to key endocrine and metabolic signalng pathways

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bile acids have historically been considered to mainly function in cholesterol homeostasis and facilitate fat digestion in the gastrointestinal tract. Recent discoveries show that bile acids also function as signaling molecules that exert diverse endocrine and metabolic actions by activating G prote...

  16. Bile Acids and Dysbiosis in Non-Alcoholic Fatty Liver Disease

    PubMed Central

    Bandsma, Robert; Comelli, Elena M.; Arendt, Bianca M.; Zhang, Ling; Fung, Scott; Fischer, Sandra E.; McGilvray, Ian G.; Allard, Johane P.

    2016-01-01

    Background & Aims Non-alcoholic fatty liver disease (NAFLD) is characterized by dysbiosis. The bidirectional effects between intestinal microbiota (IM) and bile acids (BA) suggest that dysbiosis may be accompanied by an altered bile acid (BA) homeostasis, which in turn can contribute to the metabolic dysregulation seen in NAFLD. This study sought to examine BA homeostasis in patients with NAFLD and to relate that with IM data. Methods This was a prospective, cross-sectional study of adults with biopsy-confirmed NAFLD (non-alcoholic fatty liver: NAFL or non-alcoholic steatohepatitis: NASH) and healthy controls (HC). Clinical and laboratory data, stool samples and 7-day food records were collected. Fecal BA profiles, serum markers of BA synthesis 7-alpha-hydroxy-4-cholesten-3-one (C4) and intestinal BA signalling, as well as IM composition were assessed. Results 53 subjects were included: 25 HC, 12 NAFL and 16 NASH. Levels of total fecal BA, cholic acid (CA), chenodeoxycholic acid (CDCA) and BA synthesis were higher in patients with NASH compared to HC (p<0.05 for all comparisons). The primary to secondary BA ratio was higher in NASH compared to HC (p = 0.004), but ratio of conjugated to unconjugated BAs was not different between the groups. Bacteroidetes and Clostridium leptum counts were decreased in in a subset of 16 patients with NASH compared to 25 HC, after adjusting for body mass index and weight-adjusted calorie intake (p = 0.028 and p = 0.030, respectively). C. leptum was positively correlated with fecal unconjugated lithocholic acid (LCA) (r = 0.526, p = 0.003) and inversely with unconjugated CA (r = -0.669, p<0.0001) and unconjugated CDCA (r = - 0.630, p<0.0001). FGF19 levels were not different between the groups (p = 0.114). Conclusions In adults with NAFLD, dysbiosis is associated with altered BA homeostasis, which renders them at increased risk of hepatic injury. PMID:27203081

  17. Ileal apical sodium-dependent bile acid transporter protein levels are down-regulated through ubiquitin-dependent protein degradation induced by bile acids.

    PubMed

    Miyata, Masaaki; Yamakawa, Hiroki; Hayashi, Kenjiro; Kuribayashi, Hideaki; Yamazoe, Yasushi; Yoshinari, Kouichi

    2013-08-15

    The ileal apical sodium-dependent bile acid transporter (ASBT or SLC10A2) has a crucial role in intestinal bile acid absorption. We previously reported that enterobacteria-mediated bile acid conversion was involved in the alteration of ileal ASBT expression levels. In the present study, to investigate the hypothesis that ileal ASBT protein levels are post-translationally regulated by enterobacteria-associated bile acids, alteration of ileal ASBT protein levels was analysed in mice 12 h and 24 h after anti-bacterial drug ampicillin (ABPC) treatment (100 mg/kg, single shot) that altered bile acid composition in the intestinal lumen. In ABPC-treated mice, enterobacteria-biotransformed bile acid, taurodeoxycholic acid (TDCA) and cholic acid (CA) levels were decreased, whereas taurocholic acid (TCA) and tauro-β-muricholic acid levels were increased in the intestinal lumen. Ileal ASBT protein levels in brush-border membrane vesicles (BBMVs), but not ileal Asbt mRNA levels, were significantly increased in the ABPC-treated mice, and the extent of ubiquitination of the ileal ASBT protein was reduced in the ABPC-treated mice. Treatment of ABPC-pretreated mice with CA or TDCA, but not TCA, significantly decreased ileal ASBT protein levels and increased the extent of ubiquitination of ileal ASBT protein. Treatment of mice with the lysosome inhibitor, chloroquine, or the proteasome inhibitor, MG132, increased ileal ASBT protein levels in BBMVs. CA-mediated reduction of ASBT protein levels in the ABPC-pretreated mice was attenuated by co-treatment with chloroquine or MG132. These results suggest that ileal ASBT protein is degraded by a ubiquitin-dependent pathway in response to enterobacteria-associated bile acids. PMID:23872411

  18. 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

  19. Faecal bile acids are natural ligands of the mouse accessory olfactory system.

    PubMed

    Doyle, Wayne I; Dinser, Jordan A; Cansler, Hillary L; Zhang, Xingjian; Dinh, Daniel D; Browder, Natasha S; Riddington, Ian M; Meeks, Julian P

    2016-01-01

    The accessory olfactory system (AOS) guides behaviours that are important for survival and reproduction, but understanding of AOS function is limited by a lack of identified natural ligands. Here we report that mouse faeces are a robust source of AOS chemosignals and identify bile acids as a class of natural AOS ligands. Single-unit electrophysiological recordings from accessory olfactory bulb neurons in ex vivo preparations show that AOS neurons are strongly and selectively activated by peripheral stimulation with mouse faecal extracts. Faecal extracts contain several unconjugated bile acids that cause concentration-dependent neuronal activity in the AOS. Many AOS neurons respond selectively to bile acids that are variably excreted in male and female mouse faeces, and others respond to bile acids absent in mouse faeces. These results identify faeces as a natural source of AOS information, and suggest that bile acids may be mammalian pheromones and kairomones. PMID:27324439

  20. Mechanism of bile acid-regulated glucose and lipid metabolism in duodenal-jejunal bypass

    PubMed Central

    Chai, Jie; Zou, Lei; Li, Xirui; Han, Dali; Wang, Shan; Hu, Sanyuan; Guan, Jie

    2015-01-01

    Bile acid plays an important role in regulating blood glucose, lipid and energy metabolism. The present study was implemented to determine the effect of duodenal-jejunal bypass (DJB) on FXR, TGR-5expression in terminal ileum and its bile acid-related mechanism on glucose and lipid metabolism. Immunohistochemistry was used to detect relative gene or protein expression in liver and intestine. Firstly, we found that expression of FXR in liver and terminal ileum of DJB group was significantly higher than that in S-DJB group (P<0.05). In addition, DJB dramatically increased the activation of TGR-5 in the liver of rats. Furthermore, PEPCK, G6Pase, FBPase 1 and GLP-1 were up-regulated by DJB. In conclusion, these results showed that bile acid ameliorated glucose and lipid metabolism through bile acid-FXR and bile acid- TGR-5 signaling pathway. PMID:26884847

  1. Intestinal Crosstalk between Bile Acids and Microbiota and Its Impact on Host Metabolism.

    PubMed

    Wahlström, Annika; Sayin, Sama I; Marschall, Hanns-Ulrich; Bäckhed, Fredrik

    2016-07-12

    The gut microbiota is considered a metabolic "organ" that not only facilitates harvesting of nutrients and energy from the ingested food but also produces numerous metabolites that signal through their cognate receptors to regulate host metabolism. One such class of metabolites, bile acids, is produced in the liver from cholesterol and metabolized in the intestine by the gut microbiota. These bioconversions modulate the signaling properties of bile acids via the nuclear farnesoid X receptor and the G protein-coupled membrane receptor 5, which regulate numerous metabolic pathways in the host. Conversely, bile acids can modulate gut microbial composition both directly and indirectly through activation of innate immune genes in the small intestine. Thus, host metabolism can be affected through microbial modifications of bile acids, which lead to altered signaling via bile acid receptors, but also by altered microbiota composition. PMID:27320064

  2. Nuclear receptor-dependent bile acid signaling is required for normal liver regeneration.

    PubMed

    Huang, Wendong; Ma, Ke; Zhang, Jun; Qatanani, Mohammed; Cuvillier, James; Liu, Jun; Dong, Bingning; Huang, Xiongfei; Moore, David D

    2006-04-14

    Liver mass depends on one or more unidentified humoral signals that drive regeneration when liver functional capacity is diminished. Bile acids are important liver products, and their levels are tightly regulated. Here, we identify a role for nuclear receptor-dependent bile acid signaling in normal liver regeneration. Elevated bile acid levels accelerate regeneration, and decreased levels inhibit liver regrowth, as does the absence of the primary nuclear bile acid receptor FXR. We propose that FXR activation by increased bile acid flux is a signal of decreased functional capacity of the liver. FXR, and possibly other nuclear receptors, may promote homeostasis not only by regulating expression of appropriate metabolic target genes but also by driving homeotrophic liver growth. PMID:16614213

  3. Faecal bile acids are natural ligands of the mouse accessory olfactory system

    PubMed Central

    Doyle, Wayne I.; Dinser, Jordan A.; Cansler, Hillary L.; Zhang, Xingjian; Dinh, Daniel D.; Browder, Natasha S.; Riddington, Ian M.; Meeks, Julian P.

    2016-01-01

    The accessory olfactory system (AOS) guides behaviours that are important for survival and reproduction, but understanding of AOS function is limited by a lack of identified natural ligands. Here we report that mouse faeces are a robust source of AOS chemosignals and identify bile acids as a class of natural AOS ligands. Single-unit electrophysiological recordings from accessory olfactory bulb neurons in ex vivo preparations show that AOS neurons are strongly and selectively activated by peripheral stimulation with mouse faecal extracts. Faecal extracts contain several unconjugated bile acids that cause concentration-dependent neuronal activity in the AOS. Many AOS neurons respond selectively to bile acids that are variably excreted in male and female mouse faeces, and others respond to bile acids absent in mouse faeces. These results identify faeces as a natural source of AOS information, and suggest that bile acids may be mammalian pheromones and kairomones. PMID:27324439

  4. Protective effects of nonionic tri-block copolymers on bile acid-mediated epithelial barrier disruption.

    SciTech Connect

    Edelstein, A.; Fink, D.; Musch, M.; Valuckaite, V.; Zabornia, O.; Grubjesic, S.; Firestone, M. A.; Matthews, J. B.; Alverdy, J. C.

    2011-11-01

    Translocation of bacteria and other luminal factors from the intestine following surgical injury can be a major driver of critical illness. Bile acids have been shown to play a key role in the loss of intestinal epithelial barrier function during states of host stress. Experiments to study the ability of nonionic block copolymers to abrogate barrier failure in response to bile acid exposure are described. In vitro experiments were performed with the bile salt sodium deoxycholate on Caco-2 enterocyte monolayers using transepithelial electrical resistance to assay barrier function. A bisphenol A coupled triblock polyethylene glycol (PEG), PEG 15-20, was shown to prevent sodium deoxycholate-induced barrier failure. Enzyme-linked immunosorbent assay, lactate dehydrogenase, and caspase 3-based cell death detection assays demonstrated that bile acid-induced apoptosis and necrosis were prevented with PEG 15-20. Immunofluorescence microscopic visualization of the tight junctional protein zonula occludens 1 (ZO-1) demonstrated that PEG 15-20 prevented significant changes in tight junction organization induced by bile acid exposure. Preliminary transepithelial electrical resistance-based studies examining structure-function correlates of polymer protection against bile acid damage were performed with a small library of PEG-based copolymers. Polymer properties associated with optimal protection against bile acid-induced barrier disruption were PEG-based compounds with a molecular weight greater than 10 kd and amphiphilicity. The data demonstrate that PEG-based copolymer architecture is an important determinant that confers protection against bile acid injury of intestinal epithelia.

  5. Structural and Functional Implications of the Interaction between Macrolide Antibiotics and Bile Acids

    PubMed Central

    Glanzer, Simon; Pulido, Sergio A; Tutz, Sarah; Wagner, Gabriel E; Kriechbaum, Manfred; Gubensäk, Nina; Trifunovic, Jovana; Dorn, Markus; Fabian, Walter M F; Novak, Predrag; Reidl, Joachim; Zangger, Klaus

    2015-01-01

    Macrolide antibiotics, such as azithromycin and erythromycin, are in widespread use for the treatment of bacterial infections. Macrolides are taken up and excreted mainly by bile. Additionally, they have been implicated in biliary system diseases and to modify the excretion of other drugs through bile. Despite mounting evidence for the interplay between macrolide antibiotics and bile acids, the molecular details of this interaction remain unknown. Herein, we show by NMR measurements that macrolides directly bind to bile acid micelles. The topology of this interaction has been determined by solvent paramagnetic relaxation enhancements (solvent PREs). The macrolides were found to be bound close to the surface of the micelle. Increasing hydrophobicity of both the macrolide and the bile acid strengthen this interaction. Both bile acid and macrolide molecules show similar solvent PREs across their whole structures, indicating that there are no preferred orientations of them in the bile micelle aggregates. The binding to bile aggregates does not impede macrolide antibiotics from targeting bacteria. In fact, the toxicity of azithromycin towards enterotoxic E. coli (ETEC) is even slightly increased in the presence of bile, as was shown by effective concentration (EC50) values. PMID:25655041

  6. Bile acid salt binding with colesevelam HCl is not affected by suspension in common beverages.

    PubMed

    Hanus, Martin; Zhorov, Eugene

    2006-12-01

    It has been previously reported that anions in common beverages may bind to bile acid sequestrants (BAS), reducing their capacity for binding bile acid salts. This study examined the ability of the novel BAS colesevelam hydrochloride (HCl), in vitro, to bind bile acid sodium salts following suspension in common beverages. Equilibrium binding was evaluated under conditions of constant time and varying concentrations of bile acid salts in simulated intestinal fluid (SIF). A stock solution of sodium salts of glycochenodeoxycholic acid (GCDC), taurodeoxycholic acid (TDC), and glycocholic acid (GC), was added to each prepared sample of colesevelam HCl. Bile acid salt binding was calculated by high-performance liquid chromatography (HPLC) analysis. Kinetics experiments were conducted using constant initial bile acid salt concentrations and varying binding times. The affinity, capacity, and kinetics of colesevelam HCl binding for GCDC, TDC, and GC were not significantly altered after suspension in water, carbonated water, Coca-Cola, Sprite, grape juice, orange juice, tomato juice, or Gatorade. The amount of bile acid sodium salt bound as a function of time was unchanged by pretreatment with any beverage tested. The in vitro binding characteristics of colesevelam HCl are unchanged by suspension in common beverages. PMID:16937334

  7. Influence of Verapamil and Cyclosporin A on bile acid metabolism and transport in rat liver slices.

    PubMed

    Barth, Astrid; Braun, Jerome; Müller, Dieter

    2006-08-01

    Verapamil (V) is a specific inhibitor of the P-glycoprotein (mdr1) in the hepatocyte canalicular membrane. Cyclosporin A (CsA) as an essential immunosuppressive drug has potentially cholestatic adverse effects on the liver, but increases the expression of mdr1. In precision-cut liver slices from 34- to 40-day-old male Wistar rats 26 individual free and conjugated bile acids (BAs) as markers of hepatic transport and synthesis function were analysed after 4 h incubation with V (100 microM) or CsA (5 microM) in Krebs-Henseleit buffer. Some slices were loaded with cholic acid (CA 5 microM) or tauro-ursodeoxycholic acid (T-UDCA 5 microM) to investigate the V and CsA effects under conditions of BA supplementation. BAs were determined in tissue and medium by HPLC with postcolumn derivatisation and fluorescence detection. V and CsA, influencing different targets in BA transport, enhanced slice concentrations of T- and glyco- (G-) conjugated CA only when exogenous CA was given additionally. This BA accumulation in tissue is more reflected at decreased medium concentrations of these BAs after V and CsA incubations. Both V and CsA also inhibited CA uptake into the slices. The acidic chenodeoxycholic acid (CDCA) synthesis pathway is disturbed: T- and G-CDCA concentrations are diminished in slices and medium after V and CsA incubations. T-UDCA plus V or CsA enhanced not only its own slice concentration but also the concentration of the trihydroxylated tauro-muricholic acid (T-beta-MCA), reflecting the conversion of the accumulated dihydroxylated T-UDCA into the T-beta-MCA. The similar effects of V and CsA on BA transport and metabolism can be explained by mdr1 mediated disturbances of cellular ATP transport rather than by inhibition of individual BA transporters. PMID:16793245

  8. Increased bile acids in enterohepatic circulation by short-term calorie restriction in male mice

    SciTech Connect

    Fu, Zidong Donna; Klaassen, Curtis D.

    2013-12-15

    Previous studies showed glucose and insulin signaling can regulate bile acid (BA) metabolism during fasting or feeding. However, limited knowledge is available on the effect of calorie restriction (CR), a well-known anti-aging intervention, on BA homeostasis. To address this, the present study utilized a “dose–response” model of CR, where male C57BL/6 mice were fed 0, 15, 30, or 40% CR diets for one month, followed by BA profiling in various compartments of the enterohepatic circulation by UPLC-MS/MS technique. This study showed that 40% CR increased the BA pool size (162%) as well as total BAs in serum, gallbladder, and small intestinal contents. In addition, CR “dose-dependently” increased the concentrations of tauro-cholic acid (TCA) and many secondary BAs (produced by intestinal bacteria) in serum, such as tauro-deoxycholic acid (TDCA), DCA, lithocholic acid, ω-muricholic acid (ωMCA), and hyodeoxycholic acid. Notably, 40% CR increased TDCA by over 1000% (serum, liver, and gallbladder). Interestingly, 40% CR increased the proportion of 12α-hydroxylated BAs (CA and DCA), which correlated with improved glucose tolerance and lipid parameters. The CR-induced increase in BAs correlated with increased expression of BA-synthetic (Cyp7a1) and conjugating enzymes (BAL), and the ileal BA-binding protein (Ibabp). These results suggest that CR increases BAs in male mice possibly through orchestrated increases in BA synthesis and conjugation in liver as well as intracellular transport in ileum. - Highlights: • Dose response effects of short-term CR on BA homeostasis in male mice. • CR increased the BA pool size and many individual BAs. • CR altered BA composition (increased proportion of 12α-hydroxylated BAs). • Increased mRNAs of BA enzymes in liver (Cyp7a1 and BAL) and ileal BA binding protein.

  9. 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

  10. Bile Acids, FXR, and Metabolic Effects of Bariatric Surgery

    PubMed Central

    Noel, Olivier F.; Still, Christopher D.; Argyropoulos, George; Edwards, Michael; Gerhard, Glenn S.

    2016-01-01

    Overweight and obesity represent major risk factors for diabetes and related metabolic diseases. Obesity is associated with a chronic and progressive inflammatory response leading to the development of insulin resistance and type 2 diabetes (T2D) mellitus, although the precise mechanism mediating this inflammatory process remains poorly understood. The most effective intervention for the treatment of obesity, bariatric surgery, leads to glucose normalization and remission of T2D. Recent work in both clinical studies and animal models supports bile acids (BAs) as key mediators of these effects. BAs are involved in lipid and glucose homeostasis primarily via the farnesoid X receptor (FXR) transcription factor. BAs are also involved in regulating genes involved in inflammation, obesity, and lipid metabolism. Here, we review the novel role of BAs in bariatric surgery and the intersection between BAs and immune, obesity, weight loss, and lipid metabolism genes. PMID:27006824

  11. Nuclear bile acid signaling through the farnesoid X receptor.

    PubMed

    Mazuy, Claire; Helleboid, Audrey; Staels, Bart; Lefebvre, Philippe

    2015-05-01

    Bile acids (BAs) are amphipathic molecules produced from cholesterol by the liver. Expelled from the gallbladder upon meal ingestion, BAs serve as fat solubilizers in the intestine. BAs are reabsorbed in the ileum and return via the portal vein to the liver where, together with nutrients, they provide signals to coordinate metabolic responses. BAs act on energy and metabolic homeostasis through the activation of membrane and nuclear receptors, among which the nuclear receptor farnesoid X receptor (FXR) is an important regulator of several metabolic pathways. Highly expressed in the liver and the small intestine, FXR contributes to BA effects on metabolism, inflammation and cell cycle control. The pharmacological modulation of its activity has emerged as a potential therapeutic strategy for liver and metabolic diseases. This review highlights recent advances regarding the mechanisms by which the BA sensor FXR contributes to global signaling effects of BAs, and how FXR activity may be regulated by nutrient-sensitive signaling pathways. PMID:25511198

  12. Chronic intermittent psychological stress promotes macrophage reverse cholesterol transport by impairing bile acid absorption in mice

    PubMed Central

    Silvennoinen, Reija; Quesada, Helena; Kareinen, Ilona; Julve, Josep; Kaipiainen, Leena; Gylling, Helena; Blanco-Vaca, Francisco; Escola-Gil, Joan Carles; Kovanen, Petri T; Lee-Rueckert, Miriam

    2015-01-01

    Psychological stress is a risk factor for atherosclerosis, yet the pathophysiological mechanisms involved remain elusive. The transfer of cholesterol from macrophage foam cells to liver and feces (the macrophage-specific reverse cholesterol transport, m-RCT) is an important antiatherogenic pathway. Because exposure of mice to physical restraint, a model of psychological stress, increases serum levels of corticosterone, and as bile acid homeostasis is disrupted in glucocorticoid-treated animals, we investigated if chronic intermittent restraint stress would modify m-RCT by altering the enterohepatic circulation of bile acids. C57Bl/6J mice exposed to intermittent stress for 5 days exhibited increased transit through the large intestine and enhanced fecal bile acid excretion. Of the transcription factors and transporters that regulate bile acid homeostasis, the mRNA expression levels of the hepatic farnesoid X receptor (FXR), the bile salt export pump (BSEP), and the intestinal fibroblast growth factor 15 (FGF15) were reduced, whereas those of the ileal apical sodium-dependent bile acid transporter (ASBT), responsible for active bile acid absorption, remained unchanged. Neither did the hepatic expression of cholesterol 7α-hydroxylase (CYP7A1), the key enzyme regulating bile acid synthesis, change in the stressed mice. Evaluation of the functionality of the m-RCT pathway revealed increased fecal excretion of bile acids that had been synthesized from macrophage-derived cholesterol. Overall, our study reveals that chronic intermittent stress in mice accelerates m-RCT specifically by increasing fecal excretion of bile acids. This novel mechanism of m-RCT induction could have antiatherogenic potential under conditions of chronic stress. PMID:25969465

  13. Chronic intermittent psychological stress promotes macrophage reverse cholesterol transport by impairing bile acid absorption in mice.

    PubMed

    Silvennoinen, Reija; Quesada, Helena; Kareinen, Ilona; Julve, Josep; Kaipiainen, Leena; Gylling, Helena; Blanco-Vaca, Francisco; Escola-Gil, Joan Carles; Kovanen, Petri T; Lee-Rueckert, Miriam

    2015-05-11

    Psychological stress is a risk factor for atherosclerosis, yet the pathophysiological mechanisms involved remain elusive. The transfer of cholesterol from macrophage foam cells to liver and feces (the macrophage-specific reverse cholesterol transport, m-RCT) is an important antiatherogenic pathway. Because exposure of mice to physical restraint, a model of psychological stress, increases serum levels of corticosterone, and as bile acid homeostasis is disrupted in glucocorticoid-treated animals, we investigated if chronic intermittent restraint stress would modify m-RCT by altering the enterohepatic circulation of bile acids. C57Bl/6J mice exposed to intermittent stress for 5 days exhibited increased transit through the large intestine and enhanced fecal bile acid excretion. Of the transcription factors and transporters that regulate bile acid homeostasis, the mRNA expression levels of the hepatic farnesoid X receptor (FXR), the bile salt export pump (BSEP), and the intestinal fibroblast growth factor 15 (FGF15) were reduced, whereas those of the ileal apical sodium-dependent bile acid transporter (ASBT), responsible for active bile acid absorption, remained unchanged. Neither did the hepatic expression of cholesterol 7α-hydroxylase (CYP7A1), the key enzyme regulating bile acid synthesis, change in the stressed mice. Evaluation of the functionality of the m-RCT pathway revealed increased fecal excretion of bile acids that had been synthesized from macrophage-derived cholesterol. Overall, our study reveals that chronic intermittent stress in mice accelerates m-RCT specifically by increasing fecal excretion of bile acids. This novel mechanism of m-RCT induction could have antiatherogenic potential under conditions of chronic stress. PMID:25969465

  14. Fatty acid-amino acid conjugates diversification in Lepidopteran caterpillars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fatty acid amino acid conjugates (FACs) have been found in Noctuid as well as Sphingid caterpillar oral secretions and especially volicitin [N-(17-hydroxylinolenoyl)-L-Glutamine] and its biochemical precursor, N-linolenoyl-L-glutamine, are known elicitors of induced volatile emissions in corn plants...

  15. Microbial Biotransformations of Bile Acids as Detected by Electrospray Mass Spectrometry123

    PubMed Central

    Hagey, Lee R.; Krasowski, Matthew D.

    2013-01-01

    Many current experiments investigating the effects of diet, dietary supplements, and pre- and probiotics on the intestinal environments do not take into consideration the potential for using bile salts as markers of environmental change. Intestinal bacteria in vertebrates can metabolize bile acids into a number of different structures, with deamidation, hydroxyl group oxidation, and hydroxyl group elimination. Fecal bile acids are readily available to sample and contain a considerable structural complexity that directly relates to intestinal morphology, bile acid residence time in the intestine, and the species of microbial forms in the intestinal tract. Here we offer a classification scheme that can serve as an initial guide to interpret the different bile acid patterns expressed in vertebrate feces. PMID:23319120

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  17. Health promoting potential of cereals, grain fractions and beans as determined by their in vitro bile acid binding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Health promoting potential (Cholesterol lowering and cancer risk reduction) of foods have been determined by in-vitro bile acid binding under physiological conditions. Lowered bile acids result in reduced fat absorption, conversion of cholesterol to bile acids and reduced cancer causing secondary b...

  18. New method for the determination of bile acids in human plasma by liquid-phase microextraction using liquid chromatography-ion-trap-time-of-flight mass spectrometry.

    PubMed

    de Paiva, Maria José Nunes; Menezes, Helvécio Costa; da Silva, Júlio César Cardoso; Resende, Rodrigo Ribeiro; Cardeal, Zenilda de Lourdes

    2015-04-01

    Bile acids (BAs) are derived from cholesterol and produced in the liver. The most abundant bile acids in humans are usually conjugated with glycine and taurine and are divided into primary BAs such as cholic acid (CA) and chenodeoxycholic acid (CDCA) and secondary BAs like deoxycholic acid (DCA), lithocholic acid (LCA) and ursodeoxycholic acid (UDCA). The differences amongst individual bile acids (BAs) are significant in order to distinguish different pathological processes and exposure to chemical compounds. Hollow fiber based liquid-phase microextraction (HF-LPME) is a technique that combines sample cleansing, extraction and the concentration of analytes, where a hydrophobic porous capillary membrane is impregnated with an organic extraction solvent and the lumen is filled with microliters of a phase acceptor both organic by nature. The aim of this study was to develop a new method to extract bile acids from plasma through HF-LPME of two phases (octanol as the acceptor phase) using LCMS-IT-TOF. The optimized two-phased LPME procedure for the extraction of bile acids showed limits of detection 1.0 μg L(-1) and limits of quantification of 5.0 μg L(-1). The intra-assay precision ranged from 2.1 to 11.9%. The method developed was linear over the range of 5.0-200.0 μg L(-1) for all analytes. The hollow-fiber liquid-phase microextraction method was applied to human plasma from workers exposed to organic and halogenated solvents and also to unexposed volunteers. The method is simple, low cost and it does not require large amounts of organic solvents, therefore it is quite suitable for the analysis of bile acids exposed to hepatotoxic compounds. PMID:25721909

  19. Bile acids are toxic for isolated cardiac mitochondria: a possible cause for hepatic-derived cardiomyopathies?

    PubMed

    Ferreira, Manuela; Coxito, Pedro M; Sardão, Vilma A; Palmeira, Carlos M; Oliveira, Paulo J

    2005-01-01

    Cholestasis and other liver diseases may affect the heart through the toxic effects of the retained bile acids on cardiac mitochondria, which could explain the origin of hepatic-derived cardiomyopathies. The objective of this work was to test the hypothesis that bile acids are toxic to heart mitochondria for concentrations that are relevant for cholestasis. Heart mitochondria were isolated from rat and subjected to incubation with selected bile acids (litocholic acid [LCA], deoxycholic acid [DCA], chenodeoxycholic acid [CDCA], glycochenodeoxycholic acid [GCDC], taurodeoxycholic acid [TDCA], and glycoursodeoxycholic acid [GUDC]). We observed that the most toxic bile acids were also the most lipophilic ones (LCA, DCA, and CDCA), inducing a decrease on state 3 respiration, respiratory control ratio, and membrane potential and causing the induction of the mitochondrial permeability transition. GUDC was the bile acid with lower indexes of toxicity on isolated heart mitochondria. The results of this research indicate that at toxicologically relevant concentrations, most bile acids (mainly the most lipophilic) alter mitochondrial bioenergetics. The impairment of cardiac mitochondrial function may be an important cause for the observed cardiac alterations during cholestasis. PMID:15738586

  20. Oral delivery of taurocholic acid linked heparin-docetaxel conjugates for cancer therapy.

    PubMed

    Khatun, Zehedina; Nurunnabi, Md; Reeck, Gerald R; Cho, Kwang Jae; Lee, Yong-Kyu

    2013-08-28

    We have synthesized taurocholic acid (TCA) linked heparin-docetaxel (DTX) conjugates for oral delivery of anticancer drug. The ternary biomolecular conjugates formed self-assembly nanoparticles where docetaxel was located inside the core and taurocholic acid was located on the surface of the nanoparticles. The coupled taurocholic acid in the nanoparticles had enhanced oral absorption, presumably through the stimulation of a bile acid transporter of the small intestine. The oral absorption profile demonstrated that the concentration of the conjugates in plasma is about 6 fold higher than heparin alone. An anti-tumor study in MDA-MB231 and KB tumor bearing mice showed significant tumor growth inhibition activity by the ternary biomolecular conjugates. Ki-67 histology study also showed evidence of anticancer activity of the nanoparticles. Finally, noninvasive imaging using a Kodak Molecular Imaging System demonstrated that the nanoparticles were accumulated efficiently in tumors. Thus, this approach for oral delivery using taurocholic acid in the ternary biomolecular conjugates is promising for treatment of various types of cancer. PMID:23665255

  1. Bile acid production in human subjects: rate of oxidation of (24,25-/sup 3/H)cholesterol compared to fecal bile acid excretion

    SciTech Connect

    Davidson, N.O.; Bradlow, H.L.; Ahrens, E.H. Jr.; Rosenfeld, R.S.; Schwartz, C.C.

    1986-02-01

    Bile acid production has been quantitated in seven subjects by methods that compare the results of two independent approaches, namely, quantitation of cholesterol side-chain oxidation and fecal bile acid excretion. Six hypertriglyceridemic (HT) subjects and one normolipidemic control were studied by both techniques. A further control subject was studied by the cholesterol side-chain oxidation method alone. Cholesterol side-chain oxidation was quantitated by measuring the appearance of /sup 3/H/sub 2/O after intravenous administration of (24,25-/sup 3/H)cholesterol, using multicompartmental analysis of plasma cholesterol and (/sup 3/H)water specific activity. Body water kinetics were independently defined by use of oral D/sub 2/O. Two HT subjects were restudied while they were taking cholestyramine, 16 g/day. In all ten studies, multicompartmental analysis closely simulated the observed appearance of /sup 3/H/sub 2/O. Values obtained for bile acid production suggest that cholesterol oxidation, or bile acid input, was significantly greater than fecal bile acid output in the HT subjects (P less than 0.05). Cholesterol side-chain oxidation rates in the two normal subjects were lower than those encountered in HT subjects, being similar to published values for normal subjects both for bile acid synthesis as determined by isotope dilution kinetics and fecal bile acid excretion. Studies conducted with two, synthetically different, preparations of (24,25-/sup 3/H)cholesterol indicated that, in one of the two preparations, approximately 20% of the tritium label was at positions proximal to C24. In the other preparation examined, all of the tritium was located at, or distal to, C24. Further studies revealed that 0.055-0.24% of the dose was present as labile tritium by virtue of its appearance as /sup 3/H/sub 2/O following in vitro incubation with human plasma. (Abstract Truncated)

  2. Fecal losses of sterols and bile acids induced by feeding rats guar gum are due to greater pool size and liver bile acid secretion.

    PubMed

    Moundras, C; Behr, S R; Rémésy, C; Demigné, C

    1997-06-01

    The effect of dietary guar gum (GG, 7.5%) on lipid metabolism and on bile acid secretion and reabsorption was investigated in rats adapted to cholesterol-free or 0.3% cholesterol diets. Compared with controls (fiber-free/cholesterol-free), rats fed cholesterol had significantly elevated plasma and liver cholesterol and triglyceride. In these rats, GG had a potent plasma cholesterol-lowering effect and also counteracted the liver accumulation of triglyceride and cholesterol esters. Fecal excretion of sterols, the major route of cholesterol elimination, was markedly enhanced by GG, especially in rats fed the cholesterol-containing diet (P < 0.001). The biliary bile acid flux into the small intestine was enhanced by dietary cholesterol (+30%) or GG (+52%) or both (P < 0.001). The fecal excretion of bile acids was significantly elevated by GG alone (+74%) and by dietary cholesterol (+190%). Small intestine reabsorption of bile acids appears to be significantly enhanced by GG, which also enhanced the transfer of bile acids into the large intestine, hence a greater fecal loss of steroids, although bile acid reabsorption was very effective in the cecum. GG feeding induced liver hydroxymethyl-glutaryl coenzyme A (HMG CoA) reductase, even in cholesterol-fed rats, as well as cholesterol 7 alpha-hydroxylase (P < 0.001). The cholesterol-lowering effect of GG thus appears to be mediated by an accelerated fecal excretion of steroids and a rise in the intestinal pool and biliary production of bile acids. Although liver HMG CoA reductase and cholesterol 7 alpha-hydroxylase are induced in parallel, this is not sufficient to compensate for fecal steroid losses. PMID:9187619

  3. Quantifying bile acid malabsorption helps predict response and tailor sequestrant therapy.

    PubMed

    Orekoya, Oluwafikunayo; McLaughlin, John; Leitao, Eugenia; Johns, Wendy; Lal, Simon; Paine, Peter

    2015-06-01

    Although recognised as a cause of chronic diarrhoea for over forty years, diagnostic tests and treatments for bile acid malabsorption (BAM) remain controversial. Recent National Institute for Health and Care Excellence (NICE) guidelines highlighted the lack of evidence in the field, and called for further research. This retrospective study explores the BAM subtype and severity, the use and response to bile acid sequestrants (BAS) and the prevalence of abnormal colonic histology. 264 selenium-75-labelled homocholic acid conjugated taurine (SeHCAT)-tested patient records were reviewed and the severity and subtype of BAM, presence of colonic histopathology and response to BAS were recorded. 53% of patients tested had BAM, with type-2 BAM in 45% of patients with presumed irritable bowel syndrome. Colonic histological abnormalities were similar overall between patients with (29%) or without (23%) BAM (p = 0.46) and between BAM subtypes, with no significant presence of inflammatory changes. 63% of patients with BAM had a successful BAS response which showed a trend to decreased response with reduced severity. Colestyramine was unsuccessful in 44% (38/87) and 45% of these (17/38) were related to medication intolerance, despite a positive SeHCAT. 47% (7/15) of colestyramine failures had a successful colesevelam response. No patient reported colesevelam intolerance. Quantifying severity of BAM appears to be useful in predicting BAS response. Colesevelam was better tolerated than colestyramine and showed some efficacy in colestyramine failures. Colestyramine failure should not be used to exclude BAM. Colonic histology is of no relevance. PMID:26031975

  4. Mechanism of trichloroethylene-induced elevation of individual serum bile acids. I. Correlation of trichloroethylene concentrations to bile acids in rat serum.

    PubMed

    Hamdan, H; Stacey, N H

    1993-08-01

    The temporal relationship between trichloroethylene (TRI) and individual serum bile acids (SBA) has been investigated to gain insight into the mechanism of solvent-induced increases in SBA. Male Sprague-Dawley rats were treated with 1 mmol/kg TRI in corn oil, while control rats received only corn oil. Blood samples were collected from the abdominal aorta at 2, 4, 8, and 16 hr after dosing. Individual SBA were determined by high-performance liquid chromatography (HPLC). Liver and blood concentrations of TRI and one of its metabolites, trichloroethanol (TCEOH), were determined by gas chromatography. SBA levels reached their peak at 4 hr and returned to control levels by 16 hr. There was a relationship between SBA levels and TRI concentrations, which were also at their peak 4 hr after dosing. By 16 hr the levels were undetectable. However, peak blood concentrations of TCEOH were reached 8 hr after dosing, and remained high at 16 hr. Cholic acid and taurocholic acid showed the highest levels of bile acids. Some other bile acids were also elevated, including deoxycholic acid, taurodeoxycholic acid, ursodeoxycholic acid, chenodeoxycholic acid, and taurochenodeoxycholic acid. Determination of total bile acids in serum using an enzymatic/colorimetric method showed a similar pattern of response to that obtained with the HPLC analysis. The data are consistent with TRI having a rapid and specific effect on SBA levels by a mechanism other than liver cell damage. PMID:8346545

  5. Feeding natural hydrophilic bile acids inhibits intestinal cholesterol absorption: studies in the gallstone-susceptible mouse.

    PubMed

    Wang, David Q-H; Tazuma, Susumu; Cohen, David E; Carey, Martin C

    2003-09-01

    We explored the influence of the hydrophilic-hydrophobic balance of a series of natural bile acids on cholesterol absorption in the mouse. Male C57L/J mice were fed standard chow or chow supplemented with 0.5% cholic; chenodeoxycholic; deoxycholic; dehydrocholic; hyocholic; hyodeoxycholic; alpha-, beta-, or omega-muricholic; ursocholic; or ursodeoxycholic acids for 7 days. Biliary bile salts were measured by reverse-phase HPLC, and hydrophobicity indices were estimated by Heuman's method. Cholesterol absorption efficiency was determined by a plasma dual-isotope ratio method. In mice fed chow, natural proportions of tauro-beta-muricholate (42 +/- 6%) and taurocholate (50 +/- 7%) with a hydrophobicity index of -0.35 +/- 0.04 produced cholesterol absorption of 37 +/- 5%. Because bacterial and especially hepatic biotransformations of specific bile acids occurred, hydrophobicity indices of the resultant bile salt pools differed from fed bile acids. We observed a significant positive correlation between hydrophobicity indices of the bile salt pool and percent cholesterol absorption. The principal mechanism whereby hydrophilic bile acids inhibit cholesterol absorption appears to be diminution of intraluminal micellar cholesterol solubilization. Gene expression of intestinal sterol efflux transporters Abcg5 and Abcg8 was upregulated by feeding cholic acid but not by hydrophilic beta-muricholic acid nor by hydrophobic deoxycholic acid. We conclude that the hydrophobicity of the bile salt pool predicts the effects of individual fed bile acids on intestinal cholesterol absorption. Natural alpha- and beta-muricholic acids are the most powerful inhibitors of cholesterol absorption in mice and might act as potent cholesterol-lowering agents for prevention of cholesterol deposition diseases in humans. PMID:12748061

  6. Characterization of the role of ABCG2 as a bile acid transporter in liver and placenta.

    PubMed

    Blazquez, Alba G; Briz, Oscar; Romero, Marta R; Rosales, Ruben; Monte, Maria J; Vaquero, Javier; Macias, Rocio I R; Cassio, Doris; Marin, Jose J G

    2012-02-01

    ABCG2 is involved in epithelial transport/barrier functions. Here, we have investigated its ability to transport bile acids in liver and placenta. Cholylglycylamido fluorescein (CGamF) was exported by WIF-B9/R cells, which do not express the bile salt export pump (BSEP). Sensitivity to typical inhibitors suggested that CGamF export was mainly mediated by ABCG2. In Chinese hamster ovary (CHO cells), coexpression of rat Oatp1a1 and human ABCG2 enhanced the uptake and efflux, respectively, of CGamF, cholic acid (CA), glycoCA (GCA), tauroCA, and taurolithocholic acid-3-sulfate. The ability of ABCG2 to export these bile acids was confirmed by microinjecting them together with inulin in Xenopus laevis oocytes expressing this pump. ABCG2-mediated bile acid transport was inhibited by estradiol 17β-d-glucuronide and fumitremorgin C. Placental barrier for bile acids accounted for <2-fold increase in fetal cholanemia despite >14-fold increased maternal cholanemia induced by obstructive cholestasis in pregnant rats. In rat placenta, the expression of Abcg2, which was much higher than that of Bsep, was not affected by short-term cholestasis. In pregnant rats, fumitremorgin C did not affect uptake/secretion of GCA by the liver but inhibited its fetal-maternal transfer. Compared with wild-type mice, obstructive cholestasis in pregnant Abcg2(-/-) knockout mice induced similar bile acid accumulation in maternal serum but higher accumulation in placenta, fetal serum, and liver. In conclusion, ABCG2 is able to transport bile acids. The importance of this function depends on the relative expression in the same epithelium of other bile acid exporters. Thus, ABCG2 may play a key role in bile acid transport in placenta, as BSEP does in liver. PMID:22096226

  7. Bile Acid Signaling Is Involved in the Neurological Decline in a Murine Model of Acute Liver Failure.

    PubMed

    McMillin, Matthew; Frampton, Gabriel; Quinn, Matthew; Ashfaq, Samir; de los Santos, Mario; Grant, Stephanie; DeMorrow, Sharon

    2016-02-01

    Hepatic encephalopathy is a serious neurological complication of liver failure. Serum bile acids are elevated after liver damage and may disrupt the blood-brain barrier and enter the brain. Our aim was to assess the role of serum bile acids in the neurological complications after acute liver failure. C57Bl/6 or cytochrome p450 7A1 knockout (Cyp7A1(-/-)) mice were fed a control, cholestyramine-containing, or bile acid-containing diet before azoxymethane (AOM)-induced acute liver failure. In parallel, mice were given an intracerebroventricular infusion of farnesoid X receptor (FXR) Vivo-morpholino before AOM injection. Liver damage, neurological decline, and molecular analyses of bile acid signaling were performed. Total bile acid levels were increased in the cortex of AOM-treated mice. Reducing serum bile acids via cholestyramine feeding or using Cyp7A1(-/-) mice reduced bile acid levels and delayed AOM-induced neurological decline, whereas cholic acid or deoxycholic acid feeding worsened AOM-induced neurological decline. The expression of bile acid signaling machinery apical sodium-dependent bile acid transporter, FXR, and small heterodimer partner increased in the frontal cortex, and blocking FXR signaling delayed AOM-induced neurological decline. In conclusion, circulating bile acids may play a pathological role during hepatic encephalopathy, although precisely how they dysregulate normal brain function is unknown. Strategies to minimize serum bile acid concentrations may reduce the severity of neurological complications associated with liver failure. PMID:26683664

  8. HPLC/ELSD analysis of amidated bile acids: an effective and rapid way to assist continuous flow chemistry processes.

    PubMed

    Sardella, Roccaldo; Gioiello, Antimo; Ianni, Federica; Venturoni, Francesco; Natalini, Benedetto

    2012-10-15

    The employment of the flow N-acyl amidation of natural bile acids (BAs) required the in-line connection with suitable analytical tools enabling the determination of reaction yields as well as of the purity grade of the synthesized glyco- and tauro-conjugated derivatives. In this framework, a unique HPLC method was successfully established and validated for ursodeoxycholic (UDCA), chenodeoxycholic (CDCA), deoxycholic (DCA) and cholic (CA) acids, as well as the corresponding glyco- and tauro-conjugated forms. Because of the shared absence of relevant chromophoric moieties in the sample structure, an evaporative light scattering detector (ELSD) was profitably utilized for the analysis of such steroidal species. For each of the investigated compounds, all the runs were contemporarily carried out on the acidic free and the two relative conjugated variants. The different ELSD response of the free and the corresponding conjugated BAs, imposed to build-up separate calibration curves. In all the cases, very good precision (RSD% values ranging from 1.04 to 6.40% in the long-period) and accuracy (Recovery% values ranging from 96.03 to 111.14% in the long-period) values along with appreciably low LOD and LOQ values (the former being within the range 1-27 ng mL(-1) and the latter within the range 2-44 ng mL(-1)) turned out. PMID:23141350

  9. [Chemico-physical property and bile acid binding capacity of several antacids].

    PubMed

    Salvioli, G; Tambara, E; Gaetti, E; Lugli, R

    1989-01-01

    Liquid alginate (Gaviscon) binds small amount of bile acids. At pH 7 its viscosity (at low shear rate) is higher than that of other antiacids. High viscosity reduces the diffusion rate of bile salts and glucose and this property can play a role in the treatment of gastro-esophageal and duodeno-gastric refluxes. PMID:2548124

  10. The association of bile acid excretion and atherosclerotic coronary artery disease

    PubMed Central

    Charach, Gideon; Grosskopf, Itamar; Rabinovich, Alexander; Shochat, Michael; Weintraub, Moshe; Rabinovich, Pavel

    2011-01-01

    Background: Excess cholesterol is usually eliminated from the body by conversion to bile acids excreted in feces as bile salts. The excretion of large amounts of bile protects against atherosclerosis, while diminished excretion may lead to coronary artery disease (CAD). Objective: To investigate a relationship between CAD and bile acid excretion. Methods: Bile acid excretion was compared between 36 patients with proven CAD and 37 CAD-free individuals (controls). The groups were comparable for demographics and selected risk factors. All subjects received a 4-day standard diet that included ∼500 mg of cholesterol. Fecal bile acids from 24-hour stool collections were measured by gas liquid chromatography. Results: CAD patients excreted lower amounts of total bile acids (358 ± 156 mg) than controls (617 ± 293 mg; p < 0.01) and less deoxycholic acid (188.29 ± 98.12 mg versus 325.96 ± 198.57 mg; p < 0.0001) and less lithocholic acid (115.43 ± 71.89 mg versus 197.27 ± 126.87 mg; p < 0.01). Advanced age, male gender, left ventricular ejection fraction and total bile acid levels were significant independent factors that predicted CAD (p < 0.05). Mortality, CAD and cerebrovascular accident development rates were significantly lower for the controls at the 13-year follow up. Conclusion: CAD patients have significantly decreased bile acid excretion levels than non-CAD patients. An impaired ability to excrete cholesterol may be an additional risk factor for CAD development. PMID:21694811

  11. Formation of delta 22-bile acids in rats is not gender specific and occurs in the peroxisome.

    PubMed

    Rodrigues, C M; Kren, B T; Steer, C J; Setchell, K D

    1996-03-01

    We recently demonstrated that the formation of delta 22-bile acids is a quantitatively major pathway for normal bile acid synthesis in the adult male Sprague-Dawley rat. This pathway is specific for 7 beta-hydroxy bile acids and, when ursodeoxycholic acid is administered, delta 22-ursodeoxycholic acid appears as a major metabolite in the liver tissue, bile, intestinal contents, and plasma. The aims of this study were, therefore, to determine whether this metabolic pathway was gender specific, and to establish that the peroxisome is a site of formation of delta 22-bile acids. Bile acids were determined by gas chromatography-mass spectrometry in liver tissue, jejunum, and plasma of adult female rats and in animals fed a diet containing 0.4% and 1% ursodeoxycholic acid. Bile acid metabolism in female rats was found to be similar to that of male rats, and delta 22-beta-muricholic acid, rather than beta-muricholate, was likewise confirmed as the major muricholic acid synthesized. Ursodeoxycholic acid administration resulted in the appearance of delta 22-ursodeoxycholic acid as a major metabolite. When adult male Sprague-Dawley rats were treated with clofibrate, a drug that induces peroxisomal proliferation, liver weight increased 40-60% and total bile acid synthesis decreased markedly, but the relative composition of individual bile acids was unchanged. When ursodeoxycholic acid was added to the diet, the proportion of delta 22-bile acids relative to the corresponding saturated analogues increased significantly compared with untreated rats, indicating that clofibrate had "amplified" the pathway for formation of delta 22-bile acids. When UDCA was incubated in vitro with a peroxisomal-enriched fraction from normal adult male rat liver, delta 22-ursodeoxycholic acid was formed in proportions comparable to that observed in vivo when this bile acid was given orally. These studies establish that the pathway for the formation of delta 22-bile acids is not gender specific and

  12. NMR-based modeling and binding studies of a ternary complex between chicken liver bile acid binding protein and bile acids.

    PubMed

    Tomaselli, Simona; Ragona, Laura; Zetta, Lucia; Assfalg, Michael; Ferranti, Pasquale; Longhi, Renato; Bonvin, Alexandre M J J; Molinari, Henriette

    2007-10-01

    Chicken liver bile acid binding protein (cL-BABP) is involved in bile acid transport in the liver cytosol. A detailed study of the mechanism of binding and selectivity of bile acids binding proteins towards the physiological pool of bile salts is a key issue for the complete understanding of the role of these proteins and their involvement in cholesterol homeostasis. In the present study, we modeled the ternary complex of cL-BABP with two molecules of bile salts using the data driven docking program HADDOCK on the basis of NMR and mass spectrometry data. Docking resulted in good 3D models, satisfying the majority of experimental restraints. The docking procedure represents a necessary step to help in the structure determination and in functional analysis of such systems, in view of the high complexity of the 3D structure determination of a ternary complex with two identical ligands. HADDOCK models show that residues involved in binding are mainly located in the C-terminal end of the protein, with two loops, CD and EF, playing a major role in ligand binding. A spine, comprising polarresidues pointing toward the protein interior and involved in motion communication, has a prominent role in ligand interaction. The modeling approach has been complemented with NMR interaction and competition studies of cL-BABP with chenodeoxycholic and cholic acids. A higher affinity for chenodeoxycholic acid was observed and a Kd upper limit estimate was obtained. The binding is highly cooperative and no site selectivity was detected for the different bile salts, thus indicating that site selectivity and cooperativity are not correlated. Differences in physiological pathways and bile salt pools in different species is discussed in light of the binding results thus enlarging the body of knowledge of BABPs biological functions. PMID:17607743

  13. Comparison of bile acid synthesis determined by isotope dilution versus fecal acidic sterol output in human subjects

    SciTech Connect

    Duane, W.C.; Holloway, D.E.; Hutton, S.W.; Corcoran, P.J.; Haas, N.A.

    1982-05-01

    Fecal acidic sterol output has been found to be much lower than bile acid synthesis determined by isotope dilution. Because of this confusing discrepancy, we compared these 2 measurements done simultaneously on 13 occasions in 5 normal volunteers. In contrast to previous findings, bile acid synthesis by the Lindstedt isotope dilution method averaged 16.3% lower than synthesis simultaneously determined by fecal acidic sterol output (95% confidence limit for the difference - 22.2 to -10.4%). When one-sample determinations of bile acid pools were substituted for Lindstedt pools, bile acid synthesis by isotope dilution averaged 5.6% higher than synthesis by fecal acidic sterol output (95% confidence limits -4.9 to 16.1%). These data indicate that the 2 methods yield values in reasonably close agreement with one another. If anything, fecal acidic sterol outputs are slightly higher than synthesis by isotope dilution.

  14. Lithocholic acid feeding induces segmental bile duct obstruction and destructive cholangitis in mice.

    PubMed

    Fickert, Peter; Fuchsbichler, Andrea; Marschall, Hanns-Ulrich; Wagner, Martin; Zollner, Gernot; Krause, Robert; Zatloukal, Kurt; Jaeschke, Hartmut; Denk, Helmut; Trauner, Michael

    2006-02-01

    We determined the mechanisms of hepatobiliary injury in the lithocholic acid (LCA)-fed mouse, an increasingly used model of cholestatic liver injury. Swiss albino mice received control diet or 1% (w/w) LCA diet (for 1, 2, and 4 days), followed by assessment of liver morphology and ultrastructure, tight junctions, markers of fibrosis and key proteins of hepatobiliary function, and bile flow and composition. As expected LCA feeding led to bile infarcts, which were followed by a destructive cholangitis with activation and proliferation of periductal myofibroblasts. At the ultrastructural level, small bile ducts were frequently obstructed by crystals. Biliary-excreted fluorescence-labeled ursodeoxycholic acid accumulated in bile infarcts, whereas most infarcts did not stain with India ink injected into the common bile duct; both findings are indicative of partial biliary obstruction. Expression of the main basolateral bile acid uptake proteins (sodium-taurocholate cotransporter and organic anion-transporting polypeptide 1) was reduced, the canalicular transporters bile salt export pump and multidrug-related protein 2 were preserved, and the basolateral transporter multidrug-related protein 3 and the detoxifying enzyme sulfotransferase 2a1 were induced. Thus, we demonstrate that LCA feeding in mice leads to segmental bile duct obstruction, destructive cholangitis, periductal fibrosis, and an adaptive transporter and metabolic enzyme response. PMID:16436656

  15. Steam Cooking Significantly Improves in Vitro Bile Acid Binding of Beets, Eggplant, Asparagus, Carrots, Green Beans and Cauliflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The relative healthful potential of cooked beets, okra, eggplant, asparagus, carrots, green beans, cauliflower and turnips was evaluated by determining their in vitro bile acid binding using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two...

  16. Validated UPLC method for determination of unbound bile acids in colesevelam HCl tablets.

    PubMed

    Vallapragada, Venkata Vivekanand; Inti, Gopichand; Vidiyala, Sudhakar Rao; Jadi, Sreeramulu

    2015-01-01

    A simple, precise and accurate gradient reverse-phase ultra-performance liquid chromatographic method was developed for the quantitative determination of bile acids [glycocholic acid (GCA), glycochenodeoxycholic acid (GCDA) and taurodeoxycholic acid (TDCA)) in in vitro bile acid-binding study of Welchol tablets. The method was developed using Phenomenex Kinetex C18 (50 × 2.10 mm, 1.7 µm) column with mobile phase containing a gradient mixture of solvent A consisting of 0.02 M tetrabutylammonium phosphate (pH 7.5) and solvent B consists acetonitrile. The eluted compounds were monitored at 210 nm and the runtime was within 2 min. The binding parameter constants of Colesevelam HCl tablets 625 mg were determined using the Langmuir approximation at pH 6.8 by UPLC. The method is selective and capable of detecting bile acids in the presence of placebo matrix. The method has been validated with a lower limit of quantitation of 0.01 mM for bile acids. A linear response function was established for the range of concentrations 0.01-30.0 mM (r > 0.99) for GCA, GCDA and TDCA. The intra- and interday precision values for bile acids met the acceptance as per Food and Drug Administrations guidelines. The developed method was applied to in vitro bile acid-binding studies of Colesevelam HCl tablets. PMID:24795077

  17. Determination of bile acids in human serum by on-line restricted access material-ultra high-performance liquid chromatography-mass spectrometry.

    PubMed

    Bentayeb, K; Batlle, R; Sánchez, C; Nerín, C; Domeño, C

    2008-06-15

    This paper describes a new, fully automated on-line method combining restricted access material (RAM) extraction and ultra high-performance liquid chromatography (UHPLC) with mass spectrometric (MS) detection for determining congeners of bile acids (BAs) in human serum. In this method, low-pressure RAM and high-pressure UHPLC-MS are hyphenated by using a 2.5-mL loop-type interface. The compatibility problem between the large volume (1.2mL) of strong solvent (methanol) used for RAM elution and the need for a weak solvent in UHPLC injection has been addressed by using an auxiliary pre-column cross-flow of 0.1% aqueous formic acid. In this way, the complete 2.5mL loop volume can be injected into the UHPLC system, thereby maximizing sensitivity while maintaining good chromatographic performance. The optimised method allows the simultaneous analysis of 13 bile acids in a single run, including glycine- and taurine-conjugated bile acids, cholic acid (CA), deoxycholic acid (DCA), chenodeoxycholic acid (CDCA), ursodeoxycholic acid (UDCA), and litocholic acid. The complete analysis of a 100-microL single serum sample is performed in 30 min, providing detection limits in the pg range (corresponding with clinically relevant concentration levels) for all of the analytes except lithocholic acid, intra-day precision values (%R.S.D.) below 4% (except ursodeoxycholic acid) and inter-day precision lower than 15% (except ursodeoxycholic, glycoursodeoxycholic acid (GUDCA) and lithocholic acid). PMID:18514045

  18. Human Insulin Resistance Is Associated With Increased Plasma Levels of 12α-Hydroxylated Bile Acids

    PubMed Central

    Haeusler, Rebecca A.; Astiarraga, Brenno; Camastra, Stefania; Accili, Domenico; Ferrannini, Ele

    2013-01-01

    Bile acids (BAs) exert pleiotropic metabolic effects, and physicochemical properties of different BAs affect their function. In rodents, insulin regulates BA composition, in part by regulating the BA 12α-hydroxylase CYP8B1. However, it is unclear whether a similar effect occurs in humans. To address this question, we examined the relationship between clamp-measured insulin sensitivity and plasma BA composition in a cohort of 200 healthy subjects and 35 type 2 diabetic (T2D) patients. In healthy subjects, insulin resistance (IR) was associated with increased 12α-hydroxylated BAs (cholic acid, deoxycholic acid, and their conjugated forms). Furthermore, ratios of 12α-hydroxylated/non–12α-hydroxylated BAs were associated with key features of IR, including higher insulin, proinsulin, glucose, glucagon, and triglyceride (TG) levels and lower HDL cholesterol. In T2D patients, BAs were nearly twofold elevated, and more hydrophobic, compared with healthy subjects, although we did not observe disproportionate increases in 12α-hydroxylated BAs. In multivariate analysis of the whole dataset, controlling for sex, age, BMI, and glucose tolerance status, higher 12α-hydroxy/non–12α-hydroxy BA ratios were associated with lower insulin sensitivity and higher plasma TGs. These findings suggest a role for 12α-hydroxylated BAs in metabolic abnormalities in the natural history of T2D and raise the possibility of developing insulin-sensitizing therapeutics based on manipulations of BA composition. PMID:23884887

  19. Dysfunction of organic anion transporting polypeptide 1a1 alters intestinal bacteria and bile acid metabolism in mice.

    PubMed

    Zhang, Youcai; Limaye, Pallavi B; Lehman-McKeeman, Lois D; Klaassen, Curtis D

    2012-01-01

    Organic anion transporting polypeptide 1a1 (Oatp1a1) is predominantly expressed in liver and is able to transport bile acids (BAs) in vitro. Male Oatp1a1-null mice have increased concentrations of taurodeoxycholic acid (TDCA), a secondary BA generated by intestinal bacteria, in both serum and livers. Therefore, in the present study, BA concentrations and intestinal bacteria in wild-type (WT) and Oatp1a1-null mice were quantified to investigate whether the increase of secondary BAs in Oatp1a1-null mice is due to alterations in intestinal bacteria. The data demonstrate that Oatp1a1-null mice : (1) have similar bile flow and BA concentrations in bile as WT mice; (2) have a markedly different BA composition in the intestinal contents, with a decrease in conjugated BAs and an increase in unconjugated BAs; (3) have BAs in the feces that are more deconjugated, desulfated, 7-dehydroxylated, 3-epimerized, and oxidized, but less 7-epimerized; (4) have 10-fold more bacteria in the small intestine, and 2-fold more bacteria in the large intestine which is majorly due to a 200% increase in Bacteroides and a 30% reduction in Firmicutes; and (5) have a different urinary excretion of bacteria-related metabolites than WT mice. In conclusion, the present study for the first time established that lack of a liver transporter (Oatp1a1) markedly alters the intestinal environment in mice, namely the bacteria composition. PMID:22496825

  20. Dysfunction of Organic Anion Transporting Polypeptide 1a1 Alters Intestinal Bacteria and Bile Acid Metabolism in Mice

    PubMed Central

    Zhang, Youcai; Limaye, Pallavi B.; Lehman-McKeeman, Lois D.; Klaassen, Curtis D.

    2012-01-01

    Organic anion transporting polypeptide 1a1 (Oatp1a1) is predominantly expressed in liver and is able to transport bile acids (BAs) in vitro. Male Oatp1a1-null mice have increased concentrations of taurodeoxycholic acid (TDCA), a secondary BA generated by intestinal bacteria, in both serum and livers. Therefore, in the present study, BA concentrations and intestinal bacteria in wild-type (WT) and Oatp1a1-null mice were quantified to investigate whether the increase of secondary BAs in Oatp1a1-null mice is due to alterations in intestinal bacteria. The data demonstrate that Oatp1a1-null mice : (1) have similar bile flow and BA concentrations in bile as WT mice; (2) have a markedly different BA composition in the intestinal contents, with a decrease in conjugated BAs and an increase in unconjugated BAs; (3) have BAs in the feces that are more deconjugated, desulfated, 7-dehydroxylated, 3-epimerized, and oxidized, but less 7-epimerized; (4) have 10-fold more bacteria in the small intestine, and 2-fold more bacteria in the large intestine which is majorly due to a 200% increase in Bacteroides and a 30% reduction in Firmicutes; and (5) have a different urinary excretion of bacteria-related metabolites than WT mice. In conclusion, the present study for the first time established that lack of a liver transporter (Oatp1a1) markedly alters the intestinal environment in mice, namely the bacteria composition. PMID:22496825

  1. Obeticholic acid, a synthetic bile acid agonist of the farnesoid X receptor, attenuates experimental autoimmune encephalomyelitis.

    PubMed

    Ho, Peggy P; Steinman, Lawrence

    2016-02-01

    Bile acids are ligands for the nuclear hormone receptor, farnesoid X receptor (FXR). The bile acid-FXR interaction regulates bile acid synthesis, transport, and cholesterol metabolism. Recently, bile acid-FXR regulation has been reported to play an integral role in both hepatic and intestinal inflammation, and in atherosclerosis. In this study, we found that FXR knockout mice had more disease severity in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Obeticholic acid (6α-ethyl-chenodeoxycholic acid, 6-ECDCA), a synthetic FXR agonist, is an orally available drug that is currently in clinical trials for the treatment of inflammatory diseases such as alcoholic hepatitis, nonalcoholic steatohepatitis, and primary biliary cirrhosis. When we treated mice exhibiting established EAE with 6-ECDCA, or the natural FXR ligand chenodeoxycholic acid (CDCA), clinical disease was ameliorated by (i) suppressing lymphocyte activation and proinflammatory cytokine production; (ii) reducing CD4(+) T cells and CD19(+) B cell populations and their expression of negative checkpoint regulators programmed cell death protein 1 (PD1), programmed death-ligand 1 (PD-L1), and B and T lymphocyte attenuator (BTLA); (iii) increasing CD8(+) T cells and PD1, PDl-1, and BTLA expression; and (iv) reducing VLA-4 expression in both the T- and B-cell populations. Moreover, adoptive transfer of 6-ECDCA- or CDCA-treated donor cells failed to transfer disease in naive recipients. Thus, we show that FXR functions as a negative regulator in neuroinflammation and we highlight that FXR agonists represent a potential previously unidentified therapy for MS. PMID:26811456

  2. Profiling of bile acids in bovine follicular fluid by fused-core-LC-MS/MS.

    PubMed

    Sánchez-Guijo, A; Blaschka, C; Hartmann, M F; Wrenzycki, C; Wudy, S A

    2016-09-01

    Bile acids (BAs) are present in follicular fluid (FF) from humans and cattle. This fact has triggered an interest on the role BAs might play in folliculogenesis and their possible association with fertility. To achieve a better understanding about this subject, new methods are needed to provide reliable information about concentrations of the most important BAs in FF. In this context, liquid chromatography-tandem mass spectrometry (LC-MS/MS) offers high specificity with a relatively simple sample workup. We developed and validated a new assay for the quick profiling of the 9 most abundant BAs in follicular fluid from cattle. The method uses 200μl of FF and can quantify cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA) and their glycine (G) and taurine (T) conjugates. Lithocholic acid (LCA), its conjugates GLCA and TLCA, and sulfated forms, were present in some samples, but their concentration was low compared to other BAs (in average, below 60ng/ml for LCA, GLCA or TLCA and below 20ng/ml for their corresponding sulfates). Method performance was studied at three quality controls for each compound in consonance with their physiological concentration. Excellent linearity and recovery were found for all compounds at every control level. Intra-day and between-day precisions (%CV) and accuracies (relative errors) were below 15% for all the compounds. Matrix effects were negligible for most of the analytes. Samples undergoing freeze-thaw showed no degradation of their BAs. The method makes use of a fused-core phenyl column coupled to a triple quadrupole tandem mass spectrometer to achieve chromatographic separation within 5min. We quantified BAs grouped in four different follicle sizes (3-5mm, 6-8mm, 9-14mm, >15mm), obtaining a similar relative BA profile for all the sizes, with CA always in higher concentration, ranging between 1600 and 18000ng/ml, approximately, followed by its conjugate glycocholic acid, GCA, which ranged between 800 and 9000ng

  3. The role of peroxisomal fatty acyl-CoA beta-oxidation in bile acid biosynthesis

    SciTech Connect

    Hayashi, H.; Miwa, A. )

    1989-11-01

    The physiological role of the peroxisomal fatty acyl-CoA beta-oxidizing system (FAOS) is not yet established. We speculated that there might be a relationship between peroxisomal degradation of long-chain fatty acids in the liver and the biosynthesis of bile acids. This was investigated using (1-{sup 14}C)butyric acid and (1-{sup 14}C)lignoceric acid as substrates of FAOS in mitochondria and peroxisomes, respectively. The incorporation of ({sup 14}C)lignoceric acid into primary bile acids was approximately four times higher than that of ({sup 14}C)butyric acid (in terms of C-2 units). The pools of these two fatty acids in the liver were exceedingly small. The incorporations of radioactivity into the primary bile acids were strongly inhibited by administration of aminotriazole, which is a specific inhibitor of peroxisomal FAOS in vivo. Aminotriazole inhibited preferentially the formation of cholate, the major primary bile acid, from both ({sup 14}C)lignoceric acid and ({sup 14}C)butyric acid, rather than the formation of chenodeoxycholate. The former inhibition was about 70% and the latter was approximately 40-50%. In view of reports that cholate is biosynthesized from endogenous cholesterol, the above results indicate that peroxisomal FAOS may have an anabolic function, supplying acetyl CoA for bile acid biosynthesis.

  4. Sources and Bioactive Properties of Conjugated Dietary Fatty Acids.

    PubMed

    Hennessy, Alan A; Ross, Paul R; Fitzgerald, Gerald F; Stanton, Catherine

    2016-04-01

    The group of conjugated fatty acids known as conjugated linoleic acid (CLA) isomers have been extensively studied with regard to their bioactive potential in treating some of the most prominent human health malignancies. However, CLA isomers are not the only group of potentially bioactive conjugated fatty acids currently undergoing study. In this regard, isomers of conjugated α-linolenic acid, conjugated nonadecadienoic acid and conjugated eicosapentaenoic acid, to name but a few, have undergone experimental assessment. These studies have indicated many of these conjugated fatty acid isomers commonly possess anti-carcinogenic, anti-adipogenic, anti-inflammatory and immune modulating properties, a number of which will be discussed in this review. The mechanisms through which these bioactivities are mediated have not yet been fully elucidated. However, existing evidence indicates that these fatty acids may play a role in modulating the expression of several oncogenes, cell cycle regulators, and genes associated with energy metabolism. Despite such bioactive potential, interest in these conjugated fatty acids has remained low relative to the CLA isomers. This may be partly attributed to the relatively recent emergence of these fatty acids as bioactives, but also due to a lack of awareness regarding sources from which they can be produced. In this review, we will also highlight the common sources of these conjugated fatty acids, including plants, algae, microbes and chemosynthesis. PMID:26968402

  5. Steam Cooking Significantly Improves In Vitro Bile Acid Binding of Collard Greens, Kale, Mustard Greens, Broccoli, Green Bell Pepper and Cabbage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bile acid binding capacity has been related to the cholesterol-lowering potential of foods and food fractions. Lowering recirculating bile acids results in utilization of cholesterol to synthesize bile acid and reduced fat absorption. Secondary bile acids have been associated with increasing the r...

  6. 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. PMID:25656736

  7. Distinct Plasma Bile Acid Profiles of Biliary Atresia and Neonatal Hepatitis Syndrome.

    PubMed

    Zhou, Kejun; Wang, Jun; Xie, Guoxiang; Zhou, Ying; Yan, Weihui; Pan, Weihua; Che, Yanran; Zhang, Ting; Wong, Linda; Kwee, Sandi; Xiao, Yongtao; Wen, Jie; Cai, Wei; Jia, Wei

    2015-11-01

    Biliary atresia (BA) is a severe chronic cholestasis disorder of infants that leads to death if not treated on time. Neonatal hepatitis syndrome (NHS) is another leading cause of neonatal cholestasis confounding the diagnosis of BA. Recent studies indicate that altered bile acid metabolism is closely associated with liver injury and cholestasis. In this study, we systematically measured the bile acid metabolome in plasma of BA, NHS, and healthy controls. Liver bile acids were also measured using biopsy samples from 48 BA and 16 NHS infants undergoing operative cholangiography as well as 5 normal adjacent nontumor liver tissues taken from hepatoblastoma patients as controls. Both BA and NHS samples had significantly elevated bile acid levels in plasma compared to normal controls. BA patients showed a distinct bile acid profile characterized by the higher taurochenodeoxycholic acid (TCDCA) level and lower chenodeoxycholic acid (CDCA) level than those in NHS patients. The ratio of TCDCA to CDCA in plasma was significantly higher in BA compared to healthy infants (p < 0.001) or NHS (p < 0.001). The area under receiver operating characteristic curve for TCDCA/CDCA to differentiate BA from NHS was 0.923 (95% CI: 0.862-0.984). These findings were supported by significantly altered expression levels of bile acid transporters and nuclear receptors in liver including farnesoid X receptor (FXR), small heterodimer partner (SHP), bile salt export pump (BSEP), and multidrug resistant protein 3 (MDR3) in BA compared to NHS. Taken together, the plasma bile acid profiles are distinct in BA, NHS, and normal infants, as characterized by the ratio of TCDCA/CDCA differentially distributed among the three groups of infants. PMID:26449593

  8. Evaluating Healthful Properties of Cereals and Cereal Fractions by Their Bile-Acid-Binding Potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The healthful, cholesterol-lowering (atherosclerosis amelioration) or detoxification of harmful metabolites (cancer prevention) potential of cereals and cereal fractions could be predicted by evaluating their in vitro bile acid binding under physiological conditions. Using equal dry matter per incu...

  9. Evaluation of two enzymatic methods of determining unsulphated serum bile acids.

    PubMed

    Hedenborg, G; Norman, A; Samuelson, K

    1984-12-01

    Two enzymatic methods of determining unsulphated 3 alpha-hydroxylated and 7 alpha-hydroxylated bile acids, respectively, were evaluated. Both methods are based on a coupled enzyme reaction involving a coloured redox indicator and absorbance measurement as the final step. Recovery and specificity were tested on human serum pools containing different bile acids added in various amounts, and by comparison of the results with those obtained by gas-liquid chromatography after group separation of bile acids from patient sera. Results from the two enzymatic methods were also compared with those determined with radioimmunoassay on a large number of patient sera. The results indicate that the enzymatic methods are useful for serum bile acid screening but more sensitive methods are necessary for investigations within the normal range. PMID:6597529

  10. Bile acid receptors as targets for the treatment of dyslipidemia and cardiovascular disease

    PubMed Central

    Porez, Geoffrey; Prawitt, Janne; Gross, Barbara; Staels, Bart

    2012-01-01

    Dyslipidemia is an important risk factor for cardiovascular disease (CVD) and atherosclerosis. When dyslipidemia coincides with other metabolic disorders such as obesity, hypertension, and glucose intolerance, defined as the metabolic syndrome (MS), individuals present an elevated risk to develop type 2 diabetes (T2D) as well as CVD. Because the MS epidemic represents a growing public health problem worldwide, the development of therapies remains a major challenge. Alterations of bile acid pool regulation in T2D have revealed a link between bile acid and metabolic homeostasis. The bile acid receptors farnesoid X receptor (FXR) and TGR5 both regulate lipid, glucose, and energy metabolism, rendering them potential pharmacological targets for MS therapy. This review discusses the mechanisms of metabolic regulation by FXR and TGR5 and the utility relevance of natural and synthetic modulators of FXR and TGR5 activity, including bile acid sequestrants, in the treatment of the MS. PMID:22550135

  11. Bile acids inhibit duodenal secretin expression via orphan nuclear receptor small heterodimer partner (SHP).

    PubMed

    Lam, Ian P Y; Lee, Leo T O; Choi, Hueng-Sik; Alpini, Gianfranco; Chow, Billy K C

    2009-07-01

    Small heterodimer partner (SHP) is an orphan nuclear receptor in which gene expression can be upregulated by bile acids. It regulates its target genes by repressing the transcriptional activities of other nuclear receptors including NeuroD, which has been shown to regulate secretin gene expression. Here, we evaluated the regulation on duodenal secretin gene expression by SHP and selected bile acids, cholic acid (CA) and chenodeoxycholic acid (CDCA). In vitro treatment of CDCA or fexaramine elevated the SHP transcript level and occupancy on secretin promoter. The increase in the SHP level, induced by bile acid treatment or overexpression, reduced secretin gene expression, whereas this gene inhibitory effect was reversed by silencing of endogenous SHP. In in vivo studies, double-immunofluorescence staining demonstrated the coexpression of secretin and SHP in mouse duodenum. Feeding mice with 1% CA-enriched rodent chow resulted in upregulation of SHP and a concomitant decrease in secretin transcript and protein levels in duodenum compared with the control group fed with normal chow. A diet enriched with 5% cholestyramine led to a decrease in SHP level and a corresponding increase in secretin expression. Overall, this study showed that bile acids via SHP inhibit duodenal secretin gene expression. Because secretin is a key hormone that stimulates bile flow in cholangiocytes, this pathway thus provides a novel means to modulate secretin-stimulated choleresis in response to intraduodenal bile acids. PMID:19372104

  12. Bile acid dysregulation, gut dysbiosis, and gastrointestinal cancer

    PubMed Central

    Tsuei, Jessica; Chau, Thinh; Mills, David; Wan, Yu-Jui Yvonne

    2015-01-01

    Because of increasingly widespread sedentary lifestyles and diets high in fat and sugar, the global diabetes and obesity epidemic continues to grow unabated. A substantial body of evidence has been accumulated which associates diabetes and obesity to dramatically higher risk of cancer development, particularly in the liver and gastrointestinal tract. Additionally, diabetic and obese individuals have been shown to suffer from dysregulation of bile acid (BA) homeostasis and dysbiosis of the intestinal microbiome. Abnormally elevated levels of cytotoxic secondary BAs and a pro-inflammatory shift in gut microbial profile have individually been linked to numerous enterohepatic diseases including cancer. However, recent findings have implicated a detrimental interplay between BA dysregulation and intestinal dysbiosis that promotes carcinogenesis along the gut–liver axis. This review seeks to examine the currently investigated interactions between the regulation of BA metabolism and activity of the intestinal microbiota and how these interactions can drive cancer formation in the context of diabesity. The precarcinogenic effects of BA dysregulation and gut dysbiosis including excessive inflammation, heightened oxidative DNA damage, and increased cell proliferation are discussed. Furthermore, by focusing on the mediatory roles of BA nuclear receptor farnesoid x receptor, ileal transporter apical sodium dependent BA transporter, and G-coupled protein receptor TGR5, this review attempts to connect BA dysregulation, gut dysbiosis, and enterohepatic carcinogenesis at a mechanistic level. A better understanding of the intricate interplay between BA homeostasis and gut microbiome can yield novel avenues to combat the impending rise in diabesity-related cancers. PMID:24951470

  13. Increased Bile Acid Synthesis and Deconjugation After Biliopancreatic Diversion.

    PubMed

    Ferrannini, Ele; Camastra, Stefania; Astiarraga, Brenno; Nannipieri, Monica; Castro-Perez, Jose; Xie, Dan; Wang, Liangsu; Chakravarthy, Manu; Haeusler, Rebecca A

    2015-10-01

    Biliopancreatic diversion (BPD) improves insulin sensitivity and decreases serum cholesterol out of proportion with weight loss. Mechanisms of these effects are unknown. One set of proposed contributors to metabolic improvements after bariatric surgeries is bile acids (BAs). We investigated the early and late effects of BPD on plasma BA levels, composition, and markers of BA synthesis in 15 patients with type 2 diabetes (T2D). We compared these to the early and late effects of Roux-en-Y gastric bypass (RYGB) in 22 patients with T2D and 16 with normal glucose tolerance. Seven weeks after BPD, insulin sensitivity had doubled and serum cholesterol had halved. At this time, BA synthesis markers and total plasma BAs, particularly unconjugated BAs, had markedly risen; this effect could not be entirely explained by low FGF19. In contrast, after RYGB, insulin sensitivity improved gradually with weight loss and cholesterol levels declined marginally; BA synthesis markers were decreased at an early time point (2 weeks) after surgery and returned to the normal range 1 year later. These findings indicate that BA synthesis contributes to the decreased serum cholesterol after BPD. Moreover, they suggest a potential role for altered enterohepatic circulation of BAs in improving insulin sensitivity and cholesterol metabolism after BPD. PMID:26015549

  14. The role of bile acids in metabolic regulation.

    PubMed

    Vítek, Libor; Haluzík, Martin

    2016-03-01

    Bile acids (BA), long believed to only have lipid-digestive functions, have emerged as novel metabolic modulators. They have important endocrine effects through multiple cytoplasmic as well as nuclear receptors in various organs and tissues. BA affect multiple functions to control energy homeostasis, as well as glucose and lipid metabolism, predominantly by activating the nuclear farnesoid X receptor and the cytoplasmic G protein-coupled BA receptor TGR5 in a variety of tissues. However, BA also are aimed at many other cellular targets in a wide array of organs and cell compartments. Their role in the pathogenesis of diabetes, obesity and other 'diseases of civilization' becomes even more clear. They also interact with the gut microbiome, with important clinical implications, further extending the complexity of their biological functions. Therefore, it is not surprising that BA metabolism is substantially modulated by bariatric surgery, a phenomenon contributing favorably to the therapeutic effects of these surgical procedures. Based on these data, several therapeutic approaches to ameliorate obesity and diabetes have been proposed to affect the cellular targets of BA. PMID:26733603

  15. Application of a Novel Tool for Diagnosing Bile Acid Diarrhoea

    PubMed Central

    Covington, James A.; Westenbrink, Eric W.; Ouaret, Nathalie; Harbord, Ruth; Bailey, Catherine; O'Connell, Nicola; Cullis, James; Williams, Nigel; Nwokolo, Chuka U.; Bardhan, Karna D.; Arasaradnam, Ramesh P.

    2013-01-01

    Bile acid diarrhoea (BAD) is a common disease that requires expensive imaging to diagnose. We have tested the efficacy of a new method to identify BAD, based on the detection of differences in volatile organic compounds (VOC) in urine headspace of BAD vs. ulcerative colitis and healthy controls. A total of 110 patients were recruited; 23 with BAD, 42 with ulcerative colitis (UC) and 45 controls. Patients with BAD also received standard imaging (Se75HCAT) for confirmation. Urine samples were collected and the headspace analysed using an AlphaMOS Fox 4000 electronic nose in combination with an Owlstone Lonestar Field Asymmetric Ion Mobility Spectrometer (FAIMS). A subset was also tested by gas chromatography, mass spectrometry (GCMS). Linear Discriminant Analysis (LDA) was used to explore both the electronic nose and FAIMS data. LDA showed statistical differences between the groups, with reclassification success rates (using an n-1 approach) at typically 83%. GCMS experiments confirmed these results and showed that patients with BAD had two chemical compounds, 2-propanol and acetamide, that were either not present or were in much reduced quantities in the ulcerative colitis and control samples. We believe that this work may lead to a new tool to diagnose BAD, which is cheaper, quicker and easier that current methods. PMID:24018955

  16. Deciphering the nuclear bile acid receptor FXR paradigm

    PubMed Central

    Modica, Salvatore; Gadaleta, Raffaella M.; Moschetta, Antonio

    2010-01-01

    Originally called retinoid X receptor interacting protein 14 (RIP14), the farnesoid X receptor (FXR) was renamed after the ability of its rat form to bind supra-physiological concentrations of farnesol. In 1999 FXR was de-orphanized since primary bile acids were identified as natural ligands. Strongly expressed in the liver and intestine, FXR has been shown to be the master transcriptional regulator of several entero-hepatic metabolic pathways with relevance to the pathophysiology of conditions such as cholestasis, fatty liver disease, cholesterol gallstone disease, intestinal inflammation and tumors. Furthermore, given the importance of FXR in the gut-liver axis feedbacks regulating lipid and glucose homeostasis, FXR modulation appears to have great input in diseases such as metabolic syndrome and diabetes. Exciting results from several cellular and animal models have provided the impetus to develop synthetic FXR ligands as novel pharmacological agents. Fourteen years from its discovery, FXR has gone from bench to bedside; a novel nuclear receptor ligand is going into clinical use. PMID:21383957

  17. Dysregulated hepatic bile acids collaboratively promote liver carcinogenesis.

    PubMed

    Xie, Guoxiang; Wang, Xiaoning; Huang, Fengjie; Zhao, Aihua; Chen, Wenlian; Yan, Jingyu; Zhang, Yunjing; Lei, Sha; Ge, Kun; Zheng, Xiaojiao; Liu, Jiajian; Su, Mingming; Liu, Ping; Jia, Wei

    2016-10-15

    Dysregulated bile acids (BAs) are closely associated with liver diseases and attributed to altered gut microbiota. Here, we show that the intrahepatic retention of hydrophobic BAs including deoxycholate (DCA), taurocholate (TCA), taurochenodeoxycholate (TCDCA), and taurolithocholate (TLCA) were substantially increased in a streptozotocin and high fat diet (HFD) induced nonalcoholic steatohepatitis-hepatocellular carcinoma (NASH-HCC) mouse model. Additionally chronic HFD-fed mice spontaneously developed liver tumors with significantly increased hepatic BA levels. Enhancing intestinal excretion of hydrophobic BAs in the NASH-HCC model mice by a 2% cholestyramine feeding significantly prevented HCC development. The gut microbiota alterations were closely correlated with altered BA levels in liver and feces. HFD-induced inflammation inhibited key BA transporters, resulting in sustained increases in intrahepatic BA concentrations. Our study also showed a significantly increased cell proliferation in BA treated normal human hepatic cell lines and a down-regulated expression of tumor suppressor gene CEBPα in TCDCA treated HepG2 cell line, suggesting that several hydrophobic BAs may collaboratively promote liver carcinogenesis. PMID:27273788

  18. Obeticholic acid, a synthetic bile acid agonist of the farnesoid X receptor, attenuates experimental autoimmune encephalomyelitis

    PubMed Central

    Ho, Peggy P.; Steinman, Lawrence

    2016-01-01

    Bile acids are ligands for the nuclear hormone receptor, farnesoid X receptor (FXR). The bile acid–FXR interaction regulates bile acid synthesis, transport, and cholesterol metabolism. Recently, bile acid–FXR regulation has been reported to play an integral role in both hepatic and intestinal inflammation, and in atherosclerosis. In this study, we found that FXR knockout mice had more disease severity in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Obeticholic acid (6α-ethyl-chenodeoxycholic acid, 6-ECDCA), a synthetic FXR agonist, is an orally available drug that is currently in clinical trials for the treatment of inflammatory diseases such as alcoholic hepatitis, nonalcoholic steatohepatitis, and primary biliary cirrhosis. When we treated mice exhibiting established EAE with 6-ECDCA, or the natural FXR ligand chenodeoxycholic acid (CDCA), clinical disease was ameliorated by (i) suppressing lymphocyte activation and proinflammatory cytokine production; (ii) reducing CD4+ T cells and CD19+ B cell populations and their expression of negative checkpoint regulators programmed cell death protein 1 (PD1), programmed death-ligand 1 (PD-L1), and B and T lymphocyte attenuator (BTLA); (iii) increasing CD8+ T cells and PD1, PDl-1, and BTLA expression; and (iv) reducing VLA-4 expression in both the T- and B-cell populations. Moreover, adoptive transfer of 6-ECDCA– or CDCA-treated donor cells failed to transfer disease in naive recipients. Thus, we show that FXR functions as a negative regulator in neuroinflammation and we highlight that FXR agonists represent a potential previously unidentified therapy for MS. PMID:26811456

  19. 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

  20. Decreased hepatotoxic bile acid composition and altered synthesis in progressive human nonalcoholic fatty liver disease.

    PubMed

    Lake, April D; Novak, Petr; Shipkova, Petia; Aranibar, Nelly; Robertson, Donald; Reily, Michael D; Lu, Zhenqiang; Lehman-McKeeman, Lois D; Cherrington, Nathan J

    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 BA 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. PMID:23391614

  1. Absence of bile acid malabsorption as a late effect of pelvic irradiation

    SciTech Connect

    Schuster, J.J.; Stryker, J.A.; Demers, L.M.; Mortel, R.

    1986-09-01

    The pathophysiology of chronic radiation-induced diarrhea was evaluated in 28 patients who had undergone pelvic irradiation for gynecologic neoplasms 2 to 7 years previously. Twenty-seven patients undergoing radiotherapy with techniques that did not require abdominal or pelvic irradiation served as controls. The glycine conjugates of cholic acid (GC) were measured in serum by radioimmunoassay. Fasting and 2 hr. pp GC levels for the pelvic irradiated patients were 11.0 +/- 11.1 (mean +/- SD) and 24.8 +/- 17.3 micrograms/dl. Fasting and 2 hr. pp GC levels for controls were 12.6 +/- 7.4 and 28.0 +/- 14.7. There were no significant differences in the post-prandial increases in serum GC between pelvic irradiated patients and controls (p = .23, Type II error probability = .13). There was also no significant difference in the 2 hr. pp and fasting GC ratio (p = .39). There was significant difference between the stool frequency (p less than .01) and the prevalence of diarrhea (p less than .02) between pelvic irradiated patients and controls. The data suggest that bile acid malabsorption due to ileal dysfunction is not an inevitable late complication of pelvic irradiation and is not the major determinant in the pathophysiology of chronic radiation-induced diarrhea.

  2. The human gut sterolbiome: bile acid-microbiome endocrine aspects and therapeutics

    PubMed Central

    Ridlon, Jason M.; Bajaj, Jasmohan S.

    2015-01-01

    The human body is now viewed as a complex ecosystem that on a cellular and gene level is mainly prokaryotic. The mammalian liver synthesizes and secretes hydrophilic primary bile acids, some of which enter the colon during the enterohepatic circulation, and are converted into numerous hydrophobic metabolites which are capable of entering the portal circulation, returned to the liver, and in humans, accumulating in the biliary pool. Bile acids are hormones that regulate their own synthesis, transport, in addition to glucose and lipid homeostasis, and energy balance. The gut microbial community through their capacity to produce bile acid metabolites distinct from the liver can be thought of as an “endocrine organ” with potential to alter host physiology, perhaps to their own favor. We propose the term “sterolbiome” to describe the genetic potential of the gut microbiome to produce endocrine molecules from endogenous and exogenous steroids in the mammalian gut. The affinity of secondary bile acid metabolites to host nuclear receptors is described, the potential of secondary bile acids to promote tumors, and the potential of bile acids to serve as therapeutic agents are discussed. PMID:26579434

  3. Regulation of Bile Acid Synthesis by Fat-soluble Vitamins A and D*

    PubMed Central

    Schmidt, Daniel R.; Holmstrom, Sam R.; Fon Tacer, Klementina; Bookout, Angie L.; Kliewer, Steven A.; Mangelsdorf, David J.

    2010-01-01

    Bile acids are required for proper absorption of dietary lipids, including fat-soluble vitamins. Here, we show that the dietary vitamins A and D inhibit bile acid synthesis by repressing hepatic expression of the rate-limiting enzyme CYP7A1. Receptors for vitamin A and D induced expression of Fgf15, an intestine-derived hormone that acts on liver to inhibit Cyp7a1. These effects were mediated through distinct cis-acting response elements in the promoter and intron of Fgf15. Interestingly, transactivation of both response elements appears to be required to maintain basal Fgf15 expression levels in vivo. Furthermore, whereas induction of Fgf15 by vitamin D is mediated through its receptor, the induction of Fgf15 by vitamin A is mediated through the retinoid X receptor/farnesoid X receptor heterodimer and is independent of bile acids, suggesting that this heterodimer functions as a distinct dietary vitamin A sensor. Notably, vitamin A treatment reversed the effects of the bile acid sequestrant cholestyramine on Fgf15, Shp, and Cyp7a1 expression, suggesting a potential therapeutic benefit of vitamin A under conditions of bile acid malabsorption. These results reveal an unexpected link between the intake of fat-soluble vitamins A and D and bile acid metabolism, which may have evolved as a means for these dietary vitamins to regulate their own absorption. PMID:20233723

  4. The human gut sterolbiome: bile acid-microbiome endocrine aspects and therapeutics.

    PubMed

    Ridlon, Jason M; Bajaj, Jasmohan S

    2015-03-01

    The human body is now viewed as a complex ecosystem that on a cellular and gene level is mainly prokaryotic. The mammalian liver synthesizes and secretes hydrophilic primary bile acids, some of which enter the colon during the enterohepatic circulation, and are converted into numerous hydrophobic metabolites which are capable of entering the portal circulation, returned to the liver, and in humans, accumulating in the biliary pool. Bile acids are hormones that regulate their own synthesis, transport, in addition to glucose and lipid homeostasis, and energy balance. The gut microbial community through their capacity to produce bile acid metabolites distinct from the liver can be thought of as an "endocrine organ" with potential to alter host physiology, perhaps to their own favor. We propose the term "sterolbiome" to describe the genetic potential of the gut microbiome to produce endocrine molecules from endogenous and exogenous steroids in the mammalian gut. The affinity of secondary bile acid metabolites to host nuclear receptors is described, the potential of secondary bile acids to promote tumors, and the potential of bile acids to serve as therapeutic agents are discussed. PMID:26579434

  5. 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.

    PubMed

    Meng, Qiang; Chen, Xin-Li; Wang, Chang-Yuan; Liu, Qi; Sun, Hui-Jun; Sun, Peng-Yuan; Huo, Xiao-Kui; Liu, Zhi-Hao; Yao, Ji-Hong; Liu, Ke-Xin

    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) 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. PMID:25655198

  6. Diagnostic Methods for Bile Acid Malabsorption in Clinical Practice

    PubMed Central

    Vijayvargiya, Priya; Camilleri, Michael; Shin, Andrea; Saenger, Amy

    2013-01-01

    Altered bile acid (BA) concentrations in the colon may cause diarrhea or constipation. BA malabsorption (BAM) accounts for >25% of patients with irritable bowel syndrome (IBS) with diarrhea and chronic diarrhea in Western countries. As BAM is increasingly recognized, proper diagnostic methods are desired in clinical practice to help direct the most effective treatment course for the chronic bowel dysfunction. This review appraises the methodology, advantages and disadvantages of 4 tools that directly measure BAM: 14C-glycocholate breath and stool test, 75Selenium HomotauroCholic Acid Test (SeHCAT), 7 α-hydroxy-4-cholesten-3-one (C4) and fecal BAs. 14C-glycocholate is a laborious test no longer widely utilized. 75SeHCAT is validated, but not available in the United States. Serum C4 is a simple, accurate method that is applicable to a majority of patients, but requires further clinical validation. Fecal measurements to quantify total and individual fecal BAs are technically cumbersome and not widely available. Regrettably, none of these tests are routinely available in the U.S., and a therapeutic trial with a BA binder is used as a surrogate for diagnosis of BAM. Recent data suggest there is an advantage to studying fecal excretion of the individual BAs and their role in BAM; this may constitute a significant advantage of the fecal BA method over the other tests. Fecal BA test could become a routine addition to fecal fat measurement in patients with unexplained diarrhea. In summary, availability determines the choice of test among C4, SeHCAT and fecal BA; more widespread availability of such tests would enhance clinical management of these patients. PMID:23644387

  7. Dysregulation of bile acid homeostasis in parenteral nutrition mouse model.

    PubMed

    Zhan, Le; Yang, Ill; Kong, Bo; Shen, Jianliang; Gorczyca, Ludwik; Memon, Naureen; Buckley, Brian T; Guo, Grace L

    2016-01-15

    Long-term parenteral nutrition (PN) administration can lead to PN-associated liver diseases (PNALD). Although multiple risk factors have been identified for PNALD, to date, the roles of bile acids (BAs) and the pathways involved in BA homeostasis in the development and progression of PNALD are still unclear. We have established a mouse PN model with IV infusion of PN solution containing soybean oil-based lipid emulsion (SOLE). Our results showed that PN altered the expression of genes involved in a variety of liver functions at the mRNA levels. PN increased liver gene expression of Cyp7a1 and markedly decreased that of Cyp8b1, Cyp7b1, Bsep, and Shp. CYP7A1 and CYP8B1 are important for synthesizing the total amount of BAs and regulating the hydrophobicity of BAs, respectively. Consistently, both the levels and the percentages of primary BAs as well as total non-12α-OH BAs increased significantly in the serum of PN mice compared with saline controls, whereas liver BA profiles were largely similar. The expression of several key liver-X receptor-α (LXRα) target genes involved in lipid synthesis was also increased in PN mouse livers. Retinoid acid-related orphan receptor-α (RORα) has been shown to induce the expression of Cyp8b1 and Cyp7b1, as well as to suppress LXRα function. Western blot showed significantly reduced nuclear migration of RORα protein in PN mouse livers. This study shows that continuous PN infusion with SOLE in mice leads to dysregulation of BA homeostasis. Alterations of liver RORα signaling in PN mice may be one of the mechanisms implicated in the pathogenesis of PNALD. PMID:26564717

  8. CAR and PXR agonists stimulate hepatic bile acid and bilirubin detoxification and elimination pathways in mice.

    PubMed

    Wagner, Martin; Halilbasic, Emina; Marschall, Hanns-Ulrich; Zollner, Gernot; Fickert, Peter; Langner, Cord; Zatloukal, Kurt; Denk, Helmut; Trauner, Michael

    2005-08-01

    Induction of hepatic phase I/II detoxification enzymes and alternative excretory pumps may limit hepatocellular accumulation of toxic biliary compounds in cholestasis. Because the nuclear xenobiotic receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR) regulate involved enzymes and transporters, we aimed to induce adaptive alternative pathways with different CAR and PXR agonists in vivo. Mice were treated with the CAR agonists phenobarbital and 1,4-bis-[2-(3,5-dichlorpyridyloxy)]benzene, as well as the PXR agonists atorvastatin and pregnenolone-16alpha-carbonitrile. Hepatic bile acid and bilirubin-metabolizing/detoxifying enzymes (Cyp2b10, Cyp3a11, Ugt1a1, Sult2a1), their regulatory nuclear receptors (CAR, PXR, farnesoid X receptor), and bile acid/organic anion and lipid transporters (Ntcp, Oatp1,2,4, Bsep, Mrp2-4, Mdr2, Abcg5/8, Asbt) in the liver and kidney were analyzed via reverse-transcriptase polymerase chain reaction and Western blotting. Potential functional relevance was tested in common bile duct ligation (CBDL). CAR agonists induced Mrp2-4 and Oatp2; PXR agonists induced only Mrp3 and Oatp2. Both PXR and CAR agonists profoundly stimulated bile acid-hydroxylating/detoxifying enzymes Cyp3a11 and Cyp2b10. In addition, CAR agonists upregulated bile acid-sulfating Sult2a1 and bilirubin-glucuronidating Ugt1a1. These changes were accompanied by reduced serum levels of bilirubin and bile acids in healthy and CBDL mice and by increased levels of polyhydroxylated bile acids in serum and urine of cholestatic mice. Atorvastatin significantly increased Oatp2, Mdr2, and Asbt, while other transporters and enzymes were moderately affected. In conclusion, administration of specific CAR or PXR ligands results in coordinated stimulation of major hepatic bile acid/bilirubin metabolizing and detoxifying enzymes and hepatic key alternative efflux systems, effects that are predicted to counteract cholestasis. PMID:15986414

  9. Mutations in the nuclear bile acid receptor FXR cause progressive familial intrahepatic cholestasis

    PubMed Central

    Gomez-Ospina, Natalia; Potter, Carol J.; Xiao, Rui; Manickam, Kandamurugu; Kim, Mi-Sun; Kim, Kang Ho; Shneider, Benjamin L.; Picarsic, Jennifer L.; Jacobson, Theodora A.; Zhang, Jing; He, Weimin; Liu, Pengfei; Knisely, A. S.; Finegold, Milton J.; Muzny, Donna M.; Boerwinkle, Eric; Lupski, James R.; Plon, Sharon E.; Gibbs, Richard A.; Eng, Christine M.; Yang, Yaping; Washington, Gabriel C.; Porteus, Matthew H.; Berquist, William E.; Kambham, Neeraja; Singh, Ravinder J.; Xia, Fan; Enns, Gregory M.; Moore, David D.

    2016-01-01

    Neonatal cholestasis is a potentially life-threatening condition requiring prompt diagnosis. Mutations in several different genes can cause progressive familial intrahepatic cholestasis, but known genes cannot account for all familial cases. Here we report four individuals from two unrelated families with neonatal cholestasis and mutations in NR1H4, which encodes the farnesoid X receptor (FXR), a bile acid-activated nuclear hormone receptor that regulates bile acid metabolism. Clinical features of severe, persistent NR1H4-related cholestasis include neonatal onset with rapid progression to end-stage liver disease, vitamin K-independent coagulopathy, low-to-normal serum gamma-glutamyl transferase activity, elevated serum alpha-fetoprotein and undetectable liver bile salt export pump (ABCB11) expression. Our findings demonstrate a pivotal function for FXR in bile acid homeostasis and liver protection. PMID:26888176

  10. Association between Circulating Vitamin D Metabolites and Fecal Bile Acid Concentrations.

    PubMed

    Jacobs, Elizabeth T; Haussler, Mark R; Alberts, David S; Kohler, Lindsay N; Lance, Peter; Martínez, María Elena; Roe, Denise J; Jurutka, Peter W

    2016-07-01

    Although hydrophobic bile acids have been demonstrated to exhibit cytotoxic and carcinogenic effects in the colorectum, ursodeoxycholic acid (UDCA) has been investigated as a potential chemopreventive agent. Vitamin D has been shown to play a role in both bile acid metabolism and in the development of colorectal neoplasia. Using a cross-sectional design, we sought to determine whether baseline circulating concentrations of the vitamin D metabolites 25(OH)D and 1,25(OH)2D were associated with baseline fecal bile acid concentrations in a trial of UDCA for the prevention of colorectal adenoma recurrence. We also prospectively evaluated whether vitamin D metabolite concentrations modified the effect of UDCA on adenoma recurrence. After adjustment for age, sex, BMI, physical activity, and calcium intake, adequate concentrations of 25(OH)D (≥30 ng/mL) were statistically significantly associated with reduced odds for high levels of total [OR, 0.61; 95% confidence interval (CI), 0.38-0.97], and primary (OR, 0.61; 95% CI, 0.38-0.96) bile acids, as well as individually with chenodeoxycholic acid (OR, 0.39; 95% CI, 0.24-0.63) and cholic acid (OR, 0.56; 95% CI, 0.36-0.90). No significant associations were observed for 1,25(OH)2D and high versus low fecal bile acid concentrations. In addition, neither 25(OH)D nor 1,25(OH)2D modified the effect of UDCA on colorectal adenoma recurrence. In conclusion, this is the first study to demonstrate an inverse relationship between circulating levels of 25(OH)D and primary fecal bile acid concentrations. These results support prior data demonstrating that vitamin D plays a key role in bile acid metabolism, and suggest a potential mechanism of action for 25(OH)D in colorectal cancer prevention. Cancer Prev Res; 9(7); 589-97. ©2016 AACR. PMID:27138789

  11. Apoptosis and modulation of cell cycle control by bile acids in human leukemia T cells.

    PubMed

    Fimognari, Carmela; Lenzi, Monia; Cantelli-Forti, Giorgio; Hrelia, Patrizia

    2009-08-01

    Depending on the nature of chemical structures, different bile acids exhibit distinct biological effects. Their therapeutic efficacy has been widely demonstrated in various liver diseases, suggesting that they might protect hepatocytes against common mechanisms of liver damage. Although it has been shown to prevent apoptotic cell death in certain cell lines, bile acids significantly inhibited cell growth and induced apoptosis in cancer cells. To better understand the pharmacological potential of bile acids in cancer cells, we investigated and compared the effects of deoxycholic acid (DCA), ursodeoxycholic acid (UDCA), and their taurine-derivatives [taurodeoxycholic acid (TDCA) and tauroursodeoxycholic acid (TUDCA), respectively] on the induction of apoptosis and inhibition of cell proliferation of a human T leukemia cell line (Jurkat cells). All the bile acids tested induced a delay in cell cycle progression. Moreover, DCA markedly increased the fraction of apoptotic cells. The effects of TDCA, UDCA, and TUDCA were different from those observed for DCA. Their primary effect was the induction of necrosis. These distinctive features suggest that the hydrophobic properties of DCA play a role in its cytotoxic potential and indicate that it is possible to create new drugs useful for cancer therapy from bile acid derivatives as lead compounds. PMID:19723064

  12. Failure of ursodeoxycholic acid to prevent a cholestatic episode in a patient with benign recurrent intrahepatic cholestasis: a study of bile acid metabolism.

    PubMed

    Crosignani, A; Podda, M; Bertolini, E; Battezzati, P M; Zuin, M; Setchell, K D

    1991-06-01

    Ursodeoxycholic acid was administered to a patient with benign recurrent intrahepatic cholestasis to prevent cholestatic episodes. A detailed study of bile acid metabolism in this patient was carried out in the anicteric and icteric phases before and after ursodeoxycholic acid (750 mg/day) administration. Urinary, biliary and serum bile acids were measured by gas chromatography-mass spectrometry and by high-performance liquid chromatography techniques. During the anicteric phase the daily urinary excretion and serum concentrations of bile acids were within normal ranges, indicating normal hepatic uptake and secretion of bile acids during the cholestasis-free period. Only slight qualitative differences from normal individuals were observed; the relative proportions of deoxycholic acid in the bile and serum were higher, and 12-oxo-lithocholic acid was the predominant urinary bile acid. During the icteric phase a marked increase in the urinary excretion of primary bile acids and C-1, C-2, C-4 and C-6 hydroxylated metabolites was found. Serum bile acid concentrations increased before the rise in bilirubin, suggesting an acute disturbance in bile acid transport at the onset of the cholestatic attack. After ursodeoxycholic acid administration in the anicteric phase, bile became enriched with the exogenous bile acid, but little qualitative change was found in the other metabolites present in the urine, serum or bile during the anicteric or icteric phases. Prolonged administration of ursodeoxycholic acid failed to prevent recurrence of a cholestatic episode, suggesting that in benign recurrent intrahepatic cholestasis, oral ursodeoxycholic acid may be of little benefit in the treatment or prevention of cholestasis despite marked enrichment of the bile acid pool with this hydrophilic bile acid. PMID:2050325

  13. Bile acids reduce endocytosis of high-density lipoprotein (HDL) in HepG2 cells.

    PubMed

    Röhrl, Clemens; Eigner, Karin; Fruhwürth, Stefanie; Stangl, Herbert

    2014-01-01

    High-density lipoprotein (HDL) transports lipids to hepatic cells and the majority of HDL-associated cholesterol is destined for biliary excretion. Cholesterol is excreted into the bile directly or after conversion to bile acids, which are also present in the plasma as they are effectively reabsorbed through the enterohepatic cycle. Here, we provide evidence that bile acids affect HDL endocytosis. Using fluorescent and radiolabeled HDL, we show that HDL endocytosis was reduced in the presence of high concentrations of taurocholate, a natural non-cell-permeable bile acid, in human hepatic HepG2 and HuH7 cells. In contrast, selective cholesteryl-ester (CE) uptake was increased. Taurocholate exerted these effects extracellularly and independently of HDL modification, cell membrane perturbation or blocking of endocytic trafficking. Instead, this reduction of endocytosis and increase in selective uptake was dependent on SR-BI. In addition, cell-permeable bile acids reduced HDL endocytosis by farnesoid X receptor (FXR) activation: chenodeoxycholate and the non-steroidal FXR agonist GW4064 reduced HDL endocytosis, whereas selective CE uptake was unaltered. Reduced HDL endocytosis by FXR activation was independent of SR-BI and was likely mediated by impaired expression of the scavenger receptor cluster of differentiation 36 (CD36). Taken together we have shown that bile acids reduce HDL endocytosis by transcriptional and non-transcriptional mechanisms. Further, we suggest that HDL endocytosis and selective lipid uptake are not necessarily tightly linked to each other. PMID:25010412

  14. Physicochemical and physiological properties of cholylsarcosine. A potential replacement detergent for bile acid deficiency states in the small intestine.

    PubMed Central

    Lillienau, J; Schteingart, C D; Hofmann, A F

    1992-01-01

    The properties of cholylsarcosine (the synthetic N-acyl conjugate of cholic acid with sarcosine [N-methylglycine]) were examined to determine its suitability as a bile acid replacement agent for conditions of bile acid deficiency in the small intestine, which causes fat malabsorption. Previous studies in rodents had shown that the compound was well transported by the liver and ileum and underwent neither deconjugation nor dehydroxylation during enterohepatic cycling. By 1H-nuclear magnetic resonance, cholylsarcosine was found to exist in dilute aqueous solution as an almost equimolar mixture of two geometric isomers--cis and trans (around the amide bond)--in contrast to cholylglycine, which was present entirely in the trans form. The critical micellization concentration was 11 mmol/liter, similar to that of cholylglycine (10 mmol/liter). By nonaqueous titrimetry, the pKa' of cholylsarcosine was 3.7, only slightly lower than that of cholylglycine (3.9). Cholylsarcosine was poorly soluble below pH 3.7, but highly soluble above pH 4. In vitro, cholylsarcosine behaved as cholylglycine with respect to promoting lipolysis by lipase/colipase. There was little difference between cholylsarcosine and cholylglycine in their solubilization of an equimolar mixture of oleic acid, oleate, and monoolein (designed to simulate digestive products of triglyceride) or in their solubilization of monooleyl-glycerol alone. When a [3H]triolein emulsion with either cholylsarcosine or cholyltaurine was infused intraduodenally in biliary fistula rats, recovery of 3H in lymph was 52 +/- 10% (mean +/- SD) for cholylsarcosine and 52 +/- 11% for cholyltaurine. When perfused into the colon of the anesthetized rabbit, cholylsarcosine (5 mmol/liter) did not influence water absorption or permeability to erythritol, in contrast to chenodeoxycholate, which induced vigorous water secretion and caused erythritol loss. We conclude that cholylsarcosine possesses the physicochemical and physiological

  15. Quantitative profiling of bile acids in blood, adipose tissue, intestine, and gall bladder samples using ultra high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Jäntti, Sirkku E; Kivilompolo, Maarit; Ohrnberg, Leena; Pietiläinen, Kirsi H; Nygren, Heli; Orešič, Matej; Hyötyläinen, Tuulia

    2014-12-01

    An ultra high performance liquid chromatography tandem mass spectrometry method (UHPLC-MS/MS) was developed for the determination of 33 target and 28 unknown bile acids (BAs) in biological samples. Sixty-one BAs could be measured in 20 min using only a small amount of sample and with a simple sample preparation. The method proved to be very sensitive (limit of detection 5-350 pg/mL, lower limit of quantitation 0.1-2.6 ng/mL), linear (R(2) > 0.99) and reproducible (typically CV <15 % in biological matrixes). The method was used to analyze human adipose tissue, plasma, and serum (from same subjects) and mouse serum, gall bladder, small intestine, and colon samples (from same animals). Cholic acid, ursodeoxycholic acid, and chenodeoxycholic acid, deoxycholic acid, and their conjugates (mainly glycine, but also taurine conjugates) were the main metabolites in human samples, and cholic acid, glycine cholic acid, and several taurine conjugates in mouse samples. Using the method, 28 unknown BAs could also be detected. UHPLC-MS/MS spectra, accurate mass, and tissue distribution suggested that nine of the unknown bile acids were taurine conjugates, 13 were glycine conjugates, and six were intact BAs, respectively. To our knowledge, this was the first time BAs were detected in adipose tissue. Results showed that 17 targeted BAs were found at ng/g level in human adipose tissue. Our findings give a novel insight of the endogenous role of BAs in adipose tissue and their role as biomarkers (e.g., in metabolic diseases). PMID:25384335

  16. Gas chromatographic separation of bile acid 3-glucosides and 3-glucuronides without prior deconjugation on a stainless-steel capillary column.

    PubMed

    Iida, T; Tazawa, S; Tamaru, T; Goto, J; Nambara, T

    1995-01-01

    A method for the gas chromatographic (GC) separation of the 3-glucoside and 3-glucuronide conjugates of bile acids without the necessity for a hydrolytic step is described. The bile acid glycosides were derivatized to their complete methyl ester trimethylsilyl (Me-TMS) or methyl ester dimethylethylsilyl (Me-DMES) ether derivatives, which in turn were chromatographed on an inert and thermostable stainless-steel capillary column, Ultra ALLOY-1 (HT), coated with a thin film (0.15 micron) of chemically bonded and cross-linked dimethylsiloxane. They exhibited a single peak of the theoretical shape without any accompanying peaks due to thermal decomposition, even at oven temperatures of 320-330 degrees C. Excellent GC separation of isomeric bile acid glycosides was achieved by the combined use of suitable derivatives and column. This method, which does not need the prior deconjugation of the glycosidic moiety, could be usefully applied to biosynthetic and metabolic studies of bile acids in biological materials. PMID:7881536

  17. Loss of nuclear receptor SHP impairs but does not eliminate negative feedback regulation of bile acid synthesis.

    PubMed

    Kerr, Thomas A; Saeki, Shigeru; Schneider, Manfred; Schaefer, Karen; Berdy, Sara; Redder, Thadd; Shan, Bei; Russell, David W; Schwarz, Margrit

    2002-06-01

    The in vivo role of the nuclear receptor SHP in feedback regulation of bile acid synthesis was examined. Loss of SHP in mice caused abnormal accumulation and increased synthesis of bile acids due to derepression of rate-limiting CYP7A1 and CYP8B1 hydroxylase enzymes in the biosynthetic pathway. Dietary bile acids induced liver damage and restored feedback regulation. A synthetic agonist of the nuclear receptor FXR was not hepatotoxic and had no regulatory effects. Reduction of the bile acid pool with cholestyramine enhanced CYP7A1 and CYP8B1 expression. We conclude that input from three negative regulatory pathways controls bile acid synthesis. One is mediated by SHP, and two are SHP independent and invoked by liver damage and changes in bile acid pool size. PMID:12062084

  18. Are conjugated linolenic acid isomers an alternative to conjugated linoleic acid isomers in obesity prevention?

    PubMed

    Miranda, Jonatan; Arias, Noemi; Fernández-Quintela, Alfredo; del Puy Portillo, María

    2014-04-01

    Despite its benefits, conjugated linoleic acid (CLA) may cause side effects after long-term administration. Because of this and the controversial efficacy of CLA in humans, alternative biomolecules that may be used as functional ingredients have been studied in recent years. Thus, conjugated linolenic acid (CLNA) has been reported to be a potential anti-obesity molecule which may have additional positive effects related to obesity. According to the results reported in obesity, CLNA needs to be given at higher doses than CLA to be effective. However, because of the few studies conducted so far, it is still difficult to reach clear conclusions about the potential use of these CLNAs in obesity and its related changes (insulin resistance, dyslipidemia, or inflammation). PMID:24029409

  19. 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

    Qi, Yunpeng; Jiang, Changtao; Cheng, Jie; Krausz, Kristopher W; Li, Tiangang; Ferrell, Jessica M; Gonzalez, Frank J; Chiang, John Y L

    2015-01-01

    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. This article is part of a Special Issue entitled Linking transcription to physiology in lipodomics. PMID:24796972

  20. 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

  1. Lipid and protein oxidation in hepatic homogenates and cell membranes exposed to bile acids.

    PubMed

    Fuentes-Broto, Lorena; Martínez-Ballarín, Enrique; Miana-Mena, Javier; Berzosa, Cesar; Piedrafita, Eduardo; Cebrián, Igor; Reiter, Russel J; García, Joaquín J

    2009-01-01

    Cholestasis occurs in a variety of hepatic diseases and causes damage due to accumulation of bile acids in the liver. The aim was to investigate the effect of several bile acids, i.e. chenodeoxycholic, taurochenodeoxycholic, deoxycholic, taurodeoxycholic, ursodeoxycholic, lithocholic and taurolithocholic (TLC), in inducing oxidative damage. Hepatic tissue of male Sprague-Dawley rats was incubated with or without 1 mM of each bile acid, with or without 0.1 mM FeCl(3) and 0.1 mM ascorbic acid for the purpose of generating free radicals. Several bile acids increased lipid and protein oxidation, with TLC being the most pro-oxidative (657% and 175% in homogenates and 350% and 311% in membranes, respectively). TLC also enhanced iron-induced oxidative stress to lipids (21% in homogenates and 29% in membranes) and to proteins (74% in membranes). This enhancement was dose- and time-dependent and was reduced by melatonin. These results suggest that bile acids differentially mediate hepatic oxidative stress and may be involved in the physiopathology of cholestasis. PMID:19669996

  2. Dietary hyodeoxycholic acid exerts hypolipidemic effects by reducing farnesoid X receptor antagonist bile acids in mouse enterohepatic tissues.

    PubMed

    Watanabe, Shiro; Fujita, Kyosuke

    2014-10-01

    Mice were fed a control diet or a diet supplemented with hyodeoxycholic acid, the most abundant bile acid contained in pig bile, for 4 weeks, after which their serum and livers were collected. The contents of total fatty acids of serum and liver cholesteryl esters, and of liver triglycerides, were reduced following the administration of the hyodeoxycholic acid-supplemented diet, which was mainly due to the reductions in the contents of monounsaturated fatty acids. Free cholesterol contents in the serum and liver were not changed by hyodeoxycholic acid administration. Hyodeoxycholic acid administration reduced the gene expression levels of sterol regulatory element binding protein 1c, acetyl-CoA carboxylase, fatty acid synthase, and stearoyl-CoA desaturase-1. Hyodeoxycholic acid administration markedly changes the ratio of FXR-antagonist/FXR-agonist bile acids in the enterohepatic tissues of the mice (1.13 and 7.60 in hyodeoxycholic acid and control diet groups, respectively). Our findings demonstrate that hyodeoxycholic acid administration exerts the hypolipidemic effect in mice, in which downregulations of de novo lipogenesis and desaturation of saturated fatty acids are suggested to play important roles. In addition, regulation of FXR activation through the selective modification of the enterohepatic bile acid pool may be involved in the hypolipidemic effect of hyodeoxycholic acid administration. PMID:25189147

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

    SciTech Connect

    Park, Won Il; Park, Min Jung; An, Jin Kwang; Choi, Yung Hyun; Kim, Hye Young; Cheong, JaeHun Yang, Ung Suk

    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}. 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.

  4. DOES LOSS OF BILE ACID HOMEOSTASIS MAKE MICE MELANCHOLY?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bile is at the center of the traditional medicines of many cultures. For the ancient Greeks and Romans, each of the four macrocosmic elements that comprised the natural world, fire, earth, air, and water, had a specific microcosmic reflection in the four humors from which the body was constructed: ...

  5. The Effects of Boron Derivatives on Lipid Absorption from the Intestine and on Bile Lipids and Bile Acids of Sprague Dawley Rats

    PubMed Central

    Hall, Iris H.; Reynolds, David J.; Wong, O. T.; Sood, A.; Spielvogel, B. F.

    1995-01-01

    N,N-dimethyl-n-octadecylamine borane 1 at 8 mg/kg/day, tetrakis-u-(trimethylamine boranecarboxylato)-bis(trimethyl-carboxyborane)-dicopper(II) 2 at 2.5 mg/kg/day and trimethylamine-carboxyborane 3 at 8 mg/kg/day were evaluated for their effects on bile lipids, bile acids, small intestinal absorption of cholesterol and cholic acid and liver and small intestinal enzyme activities involved in lipid metabolism. The agent administered orally elevated rat bile excretion of lipids, e.g. cholesterol and phospholipids, and compounds 2 and 3 increased the bile flow rate. These agents altered the composition of the bile acids, but there was no significant increase in lithocholic acid which is most lithogenic agent in rats. The three agents did decrease cholesterol absorption from isolated in situ intestinal duodenum loops in the presence of drug. Hepatic and small intestinal mucosa enzyme activities, e.g. ATP-dependent citrate lyase, acyl CoA cholesterol acyl transferase, cholsterol-7-α -hydroxylase, sn glycerol-3-phosphate acyl transferase, phosphatidylate phosphohydrolase, and lipoprotein lipase, were reduced. However, the boron derivatives 1 and 3 decreased hepatic HMG-CoA reductase activity, the regulatory enzyme for cholesterol synthesis, but the compounds had no effects on small intestinal mucosa HMG-CoA reductase activity. There was no evidence of hepatic cell damage afforded by the drugs based on clinical chemistry values which would induce alterations in bile acid concentrations after treatment of the rat. PMID:18472747

  6. Direct measurement of first-pass ileal clearance of a bile acid in humans

    SciTech Connect

    Galatola, G.; Jazrawi, R.P.; Bridges, C.; Joseph, A.E.; Northfield, T.C. )

    1991-04-01

    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, which 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%).

  7. Biomimetic Nitration of Conjugated Linoleic Acid: Formation and Characterization of Naturally Occurring Conjugated Nitrodienes

    PubMed Central

    Woodcock, Steven R.; Salvatore, Sonia R.; Bonacci, Gustavo; Schopfer, Francisco J.; Freeman, Bruce A.

    2014-01-01

    Nitro-conjugated linoleic acids (NO2-cLA), endogenous nitrodiene lipids which act as inflammatory signaling mediators, were isolated and single isomers purified from the biomimetic acidic nitration products of conjugated linoleic acid (CLA). Structures were elucidated by means of detailed NMR and HPLC–MS/MS spectroscopic analysis and the relative double bond configurations assigned. Additional synthetic methods produced useful quantities and similar isomeric distributions of these unusual and reactive compounds for biological studies and isotopic standards, and the potential conversion of nitro-linoleic to nitro-conjugated linoleic acids was explored via a facile base-catalyzed isomerization. This represents one of the few descriptions of naturally occurring conjugated nitro dienes (in particular, 1-nitro 1,3-diene), an unusual and highly reactive motif with few biological examples extant. PMID:24350701

  8. Role of Bile Acids in Liver Injury and Regeneration following Acetaminophen Overdose

    PubMed Central

    Bhushan, Bharat; Borude, Prachi; Edwards, Genea; Walesky, Chad; Cleveland, Joshua; Li, Feng; Ma, Xiaochao; Apte, Udayan

    2014-01-01

    Bile acids play a critical role in liver injury and regeneration, but their role in acetaminophen (APAP)–induced liver injury is not known. We tested the effect of bile acid modulation on APAP hepatotoxicity using C57BL/6 mice, which were fed a normal diet, a 2% cholestyramine (CSA)–containing diet for bile acid depletion, or a 0.2% cholic acid (CA)–containing diet for 1 week before treatment with 400 mg/kg APAP. CSA-mediated bile acid depletion resulted in significantly higher liver injury and delayed regeneration after APAP treatment. In contrast, 0.2% CA supplementation in the diet resulted in a moderate delay in progression of liver injury and significantly higher liver regeneration after APAP treatment. Either CSA-mediated bile acid depletion or CA supplementation did not affect hepatic CYP2E1 levels or glutathione depletion after APAP treatment. CSA-fed mice exhibited significantly higher activation of c-Jun N-terminal protein kinases and a significant decrease in intestinal fibroblast growth factor 15 mRNA after APAP treatment. In contrast, mice fed a 0.2% CA diet had significantly lower c-Jun N-terminal protein kinase activation and 12-fold higher fibroblast growth factor 15 mRNA in the intestines. Liver regeneration after APAP treatment was significantly faster in CA diet–fed mice after APAP administration secondary to rapid cyclin D1 induction. Taken together, these data indicate that bile acids play a critical role in both initiation and recovery of APAP-induced liver injury. PMID:24007882

  9. Role of bile acids in liver injury and regeneration following acetaminophen overdose.

    PubMed

    Bhushan, Bharat; Borude, Prachi; Edwards, Genea; Walesky, Chad; Cleveland, Joshua; Li, Feng; Ma, Xiaochao; Apte, Udayan

    2013-11-01

    Bile acids play a critical role in liver injury and regeneration, but their role in acetaminophen (APAP)-induced liver injury is not known. We tested the effect of bile acid modulation on APAP hepatotoxicity using C57BL/6 mice, which were fed a normal diet, a 2% cholestyramine (CSA)-containing diet for bile acid depletion, or a 0.2% cholic acid (CA)-containing diet for 1 week before treatment with 400 mg/kg APAP. CSA-mediated bile acid depletion resulted in significantly higher liver injury and delayed regeneration after APAP treatment. In contrast, 0.2% CA supplementation in the diet resulted in a moderate delay in progression of liver injury and significantly higher liver regeneration after APAP treatment. Either CSA-mediated bile acid depletion or CA supplementation did not affect hepatic CYP2E1 levels or glutathione depletion after APAP treatment. CSA-fed mice exhibited significantly higher activation of c-Jun N-terminal protein kinases and a significant decrease in intestinal fibroblast growth factor 15 mRNA after APAP treatment. In contrast, mice fed a 0.2% CA diet had significantly lower c-Jun N-terminal protein kinase activation and 12-fold higher fibroblast growth factor 15 mRNA in the intestines. Liver regeneration after APAP treatment was significantly faster in CA diet-fed mice after APAP administration secondary to rapid cyclin D1 induction. Taken together, these data indicate that bile acids play a critical role in both initiation and recovery of APAP-induced liver injury. PMID:24007882

  10. Hepatocyte-specific ablation of Foxa2 alters bile acid homeostasis and results in ER stress

    PubMed Central

    Bochkis, Irina M.; Rubins, Nir E.; White, Peter; Furth, Emma E.; Friedman, Joshua R.; Kaestner, Klaus H.

    2014-01-01

    Summary Production of bile by the liver is crucial for the absorption of lipophilic nutrients. Dysregulation of bile acid homeostasis can lead to cholestatic liver disease and ER stress. We show using global location analysis (“ChIP-on-Chip”) and cell-type specific gene ablation that the winged helix transcription factor Foxa2 is required for normal bile acid homeostasis. As suggested by the location analysis, deletion of Foxa2 in hepatocytes in Foxa2loxP/loxPAlfp.Cre mice leads to decreased transcription of genes encoding bile acid transporters on both the basolateral and canalicular membranes, resulting in intrahepatic cholestasis. Foxa2-deficient mice are strikingly sensitive to a diet containing cholic acid, which results in toxic accumulation of hepatic bile salts, ER stress, and liver injury. In addition, we demonstrate that expression of FOXA2 is dramatically decreased in liver samples from patients with different cholestatic syndromes, suggesting that reduced FOXA2 levels could exacerbate the injury. PMID:18660816

  11. Bile-induced DNA strand breaks and biochemical analysis of bile acids in an experimental model of anomalous arrangement of the pancreaticobiliary ducts.

    PubMed

    Masamune, K; Kunitomo, K; Sasaki, K; Yagi, K; Komi, N; Tashiro, S

    1997-08-01

    A canine experimental model for the anomalous arrangement of the pancreaticobiliary ducts (APBD) was made to investigate the effects of bile acids on carcinogenesis. Seven adult mongrel dogs underwent dorsal pancreatico-cholecystostomy to serve as a functional model for APBD, and six dogs underwent the same procedure with the pancreatic duct ligated as a control group. Bile from the gallbladder was taken 14 months after surgery for bile acid analysis by HPLC. DNA strand breaks in HeLa cells induced by the bile were also investigated in situ by nick translation method. As a result, the fraction of cholic acid tended to be lower, and that of deoxycholic acid slightly higher in APBD-dogs (N.S.). The ursodeoxycholic acid percentage in APBD-dogs significantly decreased compared with that in the control and normal dogs (p < 0.05). Extremely high frequency of DNA strand breaks was shown in only two out of seven APBD-dogs. In those two dogs, the cholic acid percentage decreased and that of deoxycholic acid increased extremely. These findings suggest that the alteration of the bile composition in APBD caused frequent DNA strand breaks and repair which might lead to gene mutation and biliary tract carcinoma. PMID:9395717

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

    SciTech Connect

    Cheng, Jie; Krausz, Kristopher W.; Li, Feng; Ma, Xiaochao; Gonzalez, Frank J.

    2013-01-15

    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-type 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.

  13. Thermosensitivity of bile acid-based oligo(ethylene glycol) stars in aqueous solutions.

    PubMed

    Strandman, Satu; Le Dévédec, Frantz; Zhu, X X

    2011-08-01

    Amphiphilic star-shaped oligo(ethylene glycol)s with a hydrophobic bile acid core and varying number of hydrophilic arms have been made. Their thermal behavior in aqueous solutions depends on the number rather than the length of the arms. The two-armed lithocholate derivative showed the strongest tendency for association and exhibited the lowest cloud point (79 °C) of the oligomers made, as well as another phase separation at a lower temperature (31 °C). The "double thermosensitivity" arising both from the salt-dependent LCST of the oligo(ethylene glycol) segments and the temperature-responsive self-assembly of amphiphilic bile acid derivative provides an interesting path in the design of bile acid-based smart materials. PMID:21661073

  14. Inhibition of ileal bile acid transporter: An emerging therapeutic strategy for chronic idiopathic constipation

    PubMed Central

    Mosińska, Paula; Fichna, Jakub; Storr, Martin

    2015-01-01

    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. PMID:26139989

  15. Synthesis, characterization and biological activity of hydroxyl-bisphosphonic analogs of bile acids.

    PubMed

    Bortolini, Olga; Fantin, Giancarlo; Fogagnolo, Marco; Rossetti, Stefano; Maiuolo, Loredana; Di Pompo, Gemma; Avnet, Sofia; Granchi, Donatella

    2012-06-01

    Bisphosphonates (BPs) are now the most widely used drugs for diseases associated with increased bone resorption, such as osteoporosis, and tumor bone diseases. A significant drawback of the BPs is their poor oral absorption that is enhanced by the presence of bile acid substituents in the bisphosphonate framework, with no toxic effects. A straightforward synthesis of bile acid-containing hydroxy-bisphosphonates and a full characterization of these pharmaceutically important molecules, including an evaluation of affinity and the mechanism of binding to hydroxyapatite, is presented. The biological activity of bile acid-containing bisphosphonate salts was determined using the neutral-red assay on the L929 cell line and primary cultures of osteoclasts. The bioactivity of the new compounds was found superior than bisphosphonates of established activity. PMID:22483634

  16. Conjugated linoleic acid-enriched beef production.

    PubMed

    Mir, Priya S; McAllister, Timothy A; Scott, Shannon; Aalhus, Jennifer; Baron, Vern; McCartney, Duane; Charmley, Edward; Goonewardene, Laki; Basarab, John; Okine, Erasmus; Weselake, Randall J; Mir, Zahir

    2004-06-01

    Canadian beef consumption is approximately 31 kg per annum, or a third of all meats consumed. Beef is a nutrient-rich food, providing good quality protein, vitamins B-6 and B-12, niacin, iron, and zinc. However, animal fats have gained the reputation of being less healthy. The identification of the anticarcinogenic effects of beef extracts due to the presence of conjugated linoleic acid (CLA) has heightened interest in increasing the amount of CLA deposited in beef. Beef cattle produce CLA and deposit these compounds in the meat; thus, beef consumers can receive bioformed CLA. Beef contains both of the bioactive CLA isomers, namely, cis-9, trans-11 and trans-10, cis-12. The relative content of these CLA isomers in beef depends on the feeds consumed by the animals during production. Feeding cattle linoleic acid-rich oils for extended periods of time increases the CLA content of beef. Depending on the type and relative maturity of the pasture, beef from pasture-fed cattle may have a higher CLA content than beef from grain- or silage-fed cattle. In feedlot animals fed high-grain diets, inclusion of dietary oil along with hay during both the growth and finishing phases led to an increase in CLA content from 2.8 to 14 mg/g beef fat, which would provide 77 mg CLA in an 85-g serving of beef. The CLAs appear to be concentrated in intramuscular and subcutaneous fat of beef cattle, with the CLA trans-10, cis-12 isomer being greater in the subcutaneous fat. PMID:15159258

  17. HPLC Quantification of 4-Nitrophenol and its Conjugated Metabolites from Bile

    PubMed Central

    Almási, Attila; Fischer, Emil; Perjési, Pál

    2011-01-01

    An isocratic ion pair RP-HPLC method with UV-Vis detection has been developed and validated for simultaneous analysis of 4-nitrophenol (PNP), 4-nitrophenyl β-glucuronide (PNP-G), and 4-nitrophenyl sulfate (PNP-S) in rat bile samples using 4-ethylphenol (ETP) as internal standard. Chromatographic separation was achieved on a C18 column by isocratic elution with a mobile phase consisted of methanol-0.01 M citrate buffer pH 6.2 (47:53 v/v) containing 0.03 M TBAB. The flow rate was 1.0 ml min−1, the detection was affected at 290 nm. Calibration plots were generated over the concentration range 1–100 μM PNP, PNP-G, PNP-S with a common lower limit of quantification of 2.5 μM. Intra- and inter-day precision and repeatability were determined at six different concentrations. Results obtained by application of the method for determination of PNP, PNP-G and PNP-S in bile fractions collected during intestinal perfusion of PNP in hyperglycemic rats are presented. PMID:22145108

  18. Effect of pravastatin on biliary lipid composition and bile acid synthesis in familial hypercholesterolaemia.

    PubMed

    Hoogerbrugge-vd Linden, N; de Rooy, F W; Jansen, H; van Blankenstein, M

    1990-03-01

    Nine patients with heterozygous familial hypercholesterolaemia were treated for eight weeks with either 40 mg pravastatin or placebo under double blind conditions. Six patients received pravastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. Treatment with pravastatin resulted in a significant decrease in plasma cholesterol caused by a decrease in low density lipoprotein cholesterol (LDL-c) of 30% (p less than 0.005). We determined the effect of this medication on the lithogenicity of bile. Cholesterol saturation index of fasting gall bladder bile decreased with 23% (p less than 0.01) from 1.06 to 0.75 during treatment with pravastatin. A reduction of 24% (p less than 0.01) in molar percentage of biliary cholesterol was seen. After treatment the total bile acid excretion in faeces and the molar percentage of biliary bile acids were not significantly changed, suggesting that pravastatin does not influence bile acid biosynthesis to a significant extent. These findings indicate that treatment with pravastatin can decrease the incidence and complications of cholesterol gall stones. PMID:2108908

  19. Physiological concentrations of bile acids down-regulate agonist induced secretion in colonic epithelial cells.

    PubMed

    Keating, Niamh; Mroz, Magdalena S; Scharl, Michael M; Marsh, Christine; Ferguson, Gail; Hofmann, Alan F; Keely, Stephen J

    2009-08-01

    In patients with bile acid malabsorption, high concentrations of bile acids enter the colon and stimulate Cl(-) and fluid secretion, thereby causing diarrhoea. However, deoxycholic acid (DCA), the predominant colonic bile acid, is normally present at lower concentrations where its role in regulating transport is unclear. Thus, the current study set out to investigate the effects of physiologically relevant DCA concentrations on colonic epithelial secretory function. Cl(-) secretion was measured as changes in short-circuit current across voltage-clamped T(84) cell monolayers. At high concentrations (0.5-1 mM), DCA acutely stimulated Cl(-) secretion but this effect was associated with cell injury, as evidenced by decreased transepithelial resistance (TER) and increased lactate dehydrogenase (LDH) release. In contrast, chronic (24 hrs) exposure to lower DCA concentrations (10-200 microM) inhibited responses to Ca(2+) and cAMP-dependent secretagogues without altering TER, LDH release, or secretagogue-induced increases in intracellular second messengers. Other bile acids - taurodeoxycholic acid, chenodeoxycholic acid and cholic acid - had similar antisecretory effects. DCA (50 microM) rapidly stimulated phosphorylation of the epidermal growth factor receptor (EGFr) and both ERK and p38 MAPKs (mitogen-activated protein kinases). The EGFr inhibitor, AG1478, and the protein synthesis inhibitor, cycloheximide, reversed the antisecretory effects of DCA, while the MAPK inhibitors, PD98059 and SB203580, did not. In summary, our studies suggest that, in contrast to its acute prosecretory effects at pathophysiological concentrations, lower, physiologically relevant, levels of DCA chronically down-regulate colonic epithelial secretory function. On the basis of these data, we propose a novel role for bile acids as physiological regulators of colonic secretory capacity. PMID:19583809

  20. Role of ion transporters in the bile acid-induced esophageal injury.

    PubMed

    Laczkó, Dorottya; Rosztóczy, András; Birkás, Klaudia; Katona, Máté; Rakonczay, Zoltán; Tiszlavicz, László; Róka, Richárd; Wittmann, Tibor; Hegyi, Péter; Venglovecz, Viktória

    2016-07-01

    Barrett's esophagus (BE) is considered to be the most severe complication of gastro-esophageal reflux disease (GERD), in which the prolonged, repetitive episodes of combined acidic and biliary reflux result in the replacement of the squamous esophageal lining by columnar epithelium. Therefore, the acid-extruding mechanisms of esophageal epithelial cells (EECs) may play an important role in the defense. Our aim was to identify the presence of acid/base transporters on EECs and to investigate the effect of bile acids on their expressions and functions. Human EEC lines (CP-A and CP-D) were acutely exposed to bile acid cocktail (BAC) and the changes in intracellular pH (pHi) and Ca(2+) concentration ([Ca(2+)]i) were measured by microfluorometry. mRNA and protein expression of ion transporters was investigated by RT-PCR, Western blot, and immunohistochemistry. We have identified the presence of a Na(+)/H(+) exchanger (NHE), Na(+)/HCO3 (-) cotransporter (NBC), and a Cl(-)-dependent HCO3 (-) secretory mechanism in CP-A and CP-D cells. Acute administration of BAC stimulated HCO3 (-) secretion in both cell lines and the NHE activity in CP-D cells by an inositol triphosphate-dependent calcium release. Chronic administration of BAC to EECs increased the expression of ion transporters compared with nontreated cells. A similar expression pattern was observed in biopsy samples from BE compared with normal epithelium. We have shown that acute administration of bile acids differently alters ion transport mechanisms of EECs, whereas chronic exposure to bile acids increases the expression of acid/base transporters. We speculate that these adaptive processes of EECs represent an important mucosal defense against the bile acid-induced epithelial injury. PMID:27198194

  1. Physiological concentrations of bile acids down‐regulate agonist induced secretion in colonic epithelial cells

    PubMed Central

    Keating, Niamh; Mroz, Magdalena S.; Scharl, Michael M.; Marsh, Christine; Ferguson, Gail; Hofmann, Alan F.

    2009-01-01

    Abstract In patients with bile acid malabsorption, high concentrations of bile acids enter the colon and stimulate Cl− and fluid secretion, thereby causing diarrhoea. However, deoxycholic acid (DCA), the predominant colonic bile acid, is normally present at lower concentrations where its role in regulating transport is unclear. Thus, the current study set out to investigate the effects of physiologically relevant DCA concentrations on colonic epithelial secretory function. Cl− secretion was measured as changes in short‐circuit current across voltage‐clamped T84 cell monolayers. At high concentrations (0.5–1 mM), DCA acutely stimulated Cl− secretion but this effect was associated with cell injury, as evidenced by decreased transepithelial resistance (TER) and increased lactate dehydrogenase (LDH) release. In contrast, chronic (24 hrs) exposure to lower DCA concentrations (10–200 μM) inhibited responses to Ca2+ and cAMP‐dependent secretagogues without altering TER, LDH release, or secretagogue‐induced increases in intracellular second messengers. Other bile acids – taurodeoxycholic acid, chenodeoxycholic acid and cholic acid – had similar antisecretory effects. DCA (50 μM) rapidly stimulated phosphorylation of the epidermal growth factor receptor (EGFr) and both ERK and p38 MAPKs (mitogen‐activated protein kinases). The EGFr inhibitor, AG1478, and the protein synthesis inhibitor, cycloheximide, reversed the antisecretory effects of DCA, while the MAPK inhibitors, PD98059 and SB203580, did not. In summary, our studies suggest that, in contrast to its acute prosecretory effects at pathophysiological concentrations, lower, physiologically relevant, levels of DCA chronically down‐regulate colonic epithelial secretory function. On the basis of these data, we propose a novel role for bile acids as physiological regulators of colonic secretory capacity. PMID:19583809

  2. 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

    SciTech Connect

    Meng, Qiang; Chen, Xin-li; Wang, Chang-yuan; Liu, Qi; Sun, Hui-jun; Sun, Peng-yuan; Huo, Xiao-kui; Liu, Zhi-hao; Yao, Ji-hong; Liu, Ke-xin

    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) 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

  3. 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

  4. The role of CYP3A4 in the biotransformation of bile acids and therapeutic implication for cholestasis

    PubMed Central

    Zhao, Kong-Nan; Chen, Chen

    2014-01-01

    CYP3A4 is a major cytochrome P450. It catalyses a broad range of substrates including xenobiotics such as clinically used drugs and endogenous compounds bile acids. Its function to detoxify bile acids could be used for treating cholestasis, which is a condition characterised by accumulation of bile acids. Although bile acids have important physiological functions, they are very toxic when their concentrations are excessively high. The accumulated bile acids in cholestasis can cause liver and other tissue injuries. Thus, control of the concentrations of bile acids is critical for treatment of cholestasis. CYP3A4 is responsively upregulated in cholestasis mediated by the nuclear receptors farnesol X receptor (FXR) and pregnane X receptor (PXR) as a defence mechanism. However, the regulation of CYP3A4 is complicated by estrogen, which is increased in cholestasis and down regulates CYP3A4 expression. The activity of CYP3A4 is also inhibited by accumulated bile acids due to their property of detergent effect. In some cholestasis cases, genetic polymorphisms of the CYP3A4 and PXR genes may interfere with the adaptive response. Further stimulation of CYP3A4 activity in cholestasis could be an effective approach for treatment of the disease. In this review, we summarise recent progress about the roles of CYP3A4 in the metabolism of bile acids, its regulation and possible implication in the treatment of cholestasis. PMID:25332983

  5. In Vitro bile acid binding of kale, mustard greens, broccoli, cabbage and green bell pepper improves with microwave cooking

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bile acid binding potential of foods and food fractions has been related to lowering the risk of heart disease and that of cancer. Sautéing or steam cooking has been observed to significantly improve bile acid binding of green/leafy vegetables. It was hypothesized that microwave cooking could impr...

  6. Tanzawaic Acids, a Chemically Novel Set of Bacterial Conjugation Inhibitors

    PubMed Central

    Getino, María; Fernández-López, Raúl; Palencia-Gándara, Carolina; Campos-Gómez, Javier; Sánchez-López, Jose M.; Martínez, Marta; Fernández, Antonio; de la Cruz, Fernando

    2016-01-01

    Bacterial conjugation is the main mechanism for the dissemination of multiple antibiotic resistance in human pathogens. This dissemination could be controlled by molecules that interfere with the conjugation process. A search for conjugation inhibitors among a collection of 1,632 natural compounds, identified tanzawaic acids A and B as best hits. They specially inhibited IncW and IncFII conjugative systems, including plasmids mobilized by them. Plasmids belonging to IncFI, IncI, IncL/M, IncX and IncH incompatibility groups were targeted to a lesser extent, whereas IncN and IncP plasmids were unaffected. Tanzawaic acids showed reduced toxicity in bacterial, fungal or human cells, when compared to synthetic conjugation inhibitors, opening the possibility of their deployment in complex environments, including natural settings relevant for antibiotic resistance dissemination. PMID:26812051

  7. Avidity Mechanism of Dendrimer–Folic Acid Conjugates

    PubMed Central

    2015-01-01

    Multivalent conjugation of folic acid has been employed to target cells overexpressing folate receptors. Such polymer conjugates have been previously demonstrated to have high avidity to folate binding protein. However, the lack of a monovalent folic acid–polymer material has prevented a full binding analysis of these conjugates, as multivalent binding mechanisms and polymer-mass mechanisms are convoluted in samples with broad distributions of folic acid-to-dendrimer ratios. In this work, the synthesis of a monovalent folic acid–dendrimer conjugate allowed the elucidation of the mechanism for increased binding between the folic acid–polymer conjugate and a folate binding protein surface. The increased avidity is due to a folate-keyed interaction between the dendrimer and protein surfaces that fits into the general framework of slow-onset, tight-binding mechanisms of ligand/protein interactions. PMID:24725205

  8. [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. PMID:1225184

  9. Oxidative stress markers, secondary bile acids and sulfated bile acids classify the clinical liver injury type: Promising diagnostic biomarkers for cholestasis.

    PubMed

    Masubuchi, Noriko; Sugihara, Masahiro; Sugita, Tomonori; Amano, Katsushi; Nakano, Masanori; Matsuura, Tomokazu

    2016-08-01

    Clinicians sometimes encounter difficulty in choosing a therapeutic strategy due to the uncertainty regarding the type of liver injury. In particular, cholestasis is difficult to diagnose by conventional markers at an early stage of disease. The aim of this study was to identify promising biomarkers for distinguishing the symptom-based types of liver injury (e.g. hepatocellular injury, cholestasis), which was derived from a rigorously statistical perspective. The associations between diagnostic biomarkers (e.g. bile acid components, oxidative stress markers and liver fibrosis markers) and the liver injury types were assessed by a multiple logistic regression analysis using 304 blood samples from patients with liver disease. As a result, reductions in the lithocholic acid (LCA) and deoxycholic acid (DCA) levels, and elevation of the serum sulfated bile acid (SSBA), liver fibrosis marker IV collagen (type IV collagen), hyaluronic acid (HA) and reactive oxygen species (ROS) levels were all significantly associated with cholestasis. On the other hand, elevations in the LCA and type IV collagen levels, and a reduction in the ursodeoxy cholic acid (UDCA) level, were significantly associated with hepatocellular injury. The receiver operating characteristic (ROC) analyses showed that the largest area under the ROC curve (AUC) was found for ROS, followed by DCA, HA, LCA, SSBA and type IV collagen in the cholestatic-type cases. These results indicated that ROS, the secondary bile acid levels such as DCA and LCA, and SSBA are promising biomarkers for cholestasis and for classifying the type of liver injuries. This comprehensive approach will allow for an accurate diagnosis, which will facilitate the selection of an appropriate therapy at the onset of disease. PMID:26325587

  10. Irinotecan (CPT-11)-induced elevation of bile acids potentiates suppression of IL-10 expression.

    PubMed

    Fang, Zhong-Ze; Zhang, Dunfang; Cao, Yun-Feng; Xie, Cen; Lu, Dan; Sun, Dong-Xue; Tanaka, Naoki; Jiang, Changtao; Chen, Qianming; Chen, Yu; Wang, Haina; Gonzalez, Frank J

    2016-01-15

    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 showed 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(+) 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. PMID:26706406

  11. Experimental Protoporphyria: Effect of Bile Acids on Liver Damage Induced by Griseofulvin

    PubMed Central

    Martinez, María del Carmen; Ruspini, Silvina Fernanda; Afonso, Susana Graciela; Meiss, Roberto; Buzaleh, Ana Maria

    2015-01-01

    The effect of bile acids administration to an experimental mice model of Protoporphyria produced by griseofulvin (Gris) was investigated. The aim was to assess whether porphyrin excretion could be accelerated by bile acids treatment in an attempt to diminish liver damage induced by Gris. Liver damage markers, heme metabolism, and oxidative stress parameters were analyzed in mice treated with Gris and deoxycholic (DXA), dehydrocholic (DHA), chenodeoxycholic, or ursodeoxycholic (URSO). The administration of Gris alone increased the activities of glutathione reductase (GRed), superoxide dismutase (SOD), alkaline phosphatase (AP), gamma glutamyl transpeptidase (GGT), and glutathione-S-transferase (GST), as well as total porphyrins, glutathione (GSH), and cytochrome P450 (CYP) levels in liver. Among the bile acids studied, DXA and DHA increased PROTO IX excretion, DXA also abolished the action of Gris, reducing lipid peroxidation and hepatic GSH and CYP levels, and the activities of GGT, AP, SOD, and GST returned to control values. However, porphyrin accumulation was not prevented by URSO; instead this bile acid reduced ALA-S and the antioxidant defense enzymes system activities. In conclusion, we postulate that DXA acid would be more effective to prevent liver damage induced by Gris. PMID:25945334

  12. Inhibition of ileal apical but not basolateral bile acid transport reduces atherosclerosis in apoE−/− mice

    PubMed Central

    Lan, Tian; Haywood, Jamie; Dawson, Paul A.

    2013-01-01

    Objective Interruption of the enterohepatic circulation of bile acids induces hepatic bile acid synthesis, increases hepatic cholesterol demand, and increases clearance of apoB-containing lipoproteins in plasma. Based on these effects, bile acid sequestrants have been used for many years to treat hypercholesterolemia and the associated atherosclerosis. The objective of this study was to determine the effect of blocking ileal apical versus basolateral membrane bile acid transport on the development of hypercholesterolemia and atherosclerosis in mouse models. Methods and Results ApoE−/− and Ldlr−/− mice deficient in the apical sodium-dependent bile acid transporter (Asbt) or apoE−/− mice deficient in the basolateral bile acid transporter (Ostα) were fed an atherogenic diet for 16 weeks. Bile acid metabolism, cholesterol metabolism, gene expression, and development of atherosclerosis were examined. Mice deficient in Asbt exhibited the classic response to interruption of the enterohepatic circulation of bile acids, including significant reductions in hepatic and plasma cholesterol levels, and reduced aortic cholesteryl ester content. Ileal Fibroblast Growth Factor-15 (FGF15) expression was significantly reduced in Asbt−/−apoE−/− mice and was inversely correlated with expression of hepatic cholesterol 7α-hydroxylase (Cyp7a1). Ileal FGF15 expression was directly correlated with plasma cholesterol levels and aortic cholesterol content. In contrast, plasma and hepatic cholesterol levels and atherosclerosis development were not reduced in apoE−/− mice deficient in Ostα. Conclusions Decreases in ileal FGF15, with subsequent increases in hepatic Cyp7a1 expression and bile acid synthesis appear to be necessary for the plasma cholesterol-lowering and atheroprotective effects associated with blocking intestinal bile acid absorption. PMID:23880190

  13. Basal efflux of bile acids contributes to drug-induced bile acid-dependent hepatocyte toxicity in rat sandwich-cultured hepatocytes.

    PubMed

    Susukida, Takeshi; Sekine, Shuichi; Ogimura, Eiichiro; Aoki, Shigeki; Oizumi, Kumiko; Horie, Toshiharu; Ito, Kousei

    2015-10-01

    The bile salt export pump (BSEP or Bsep) functions as an apical transporter to eliminate bile acids (BAs) from hepatocytes into the bile. BSEP or Bsep inhibitors engender BA retention, suggested as an underlying mechanism of cholestatic drug-induced liver injury. We previously reported a method to evaluate BSEP-mediated BA-dependent hepatocyte toxicity by using sandwich-cultured hepatocytes (SCHs). However, basal efflux transporters, including multidrug resistance-associated proteins (MRP or Mrp) 3 and 4, also participate in BA efflux. This study examined the contribution of basal efflux transporters to BA-dependent hepatocyte toxicity in rat SCHs. The apical efflux of [(3)H]taurocholic acid (TC) was potently inhibited by 10 μM cyclosporine A (CsA), with later inhibition of basal [(3)H]TC efflux, while MK571 simultaneously inhibited both apical and basal [(3)H]TC efflux. CsA-induced BA-dependent hepatocyte toxicity was 30% at most at 10 μM CsA and ∼60% at 50 μM, while MK571 exacerbated hepatocyte toxicity at concentrations of ≥50 μM. Quinidine inhibited only basal [(3)H]TC efflux and showed BA-dependent hepatocyte toxicity in rat SCHs. Hence, inhibition of basal efflux transporters as well as Bsep may precipitate BA-dependent hepatocyte toxicity in rat SCHs. PMID:26055650

  14. Artificial Lignification of Maize Cell Walls Does Not Affect Bile Acid Adsorption

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bile acid adsorption by lignified dietary fiber in the human intestine is proposed as a mechanism for lowering blood cholesterol level and reducing colon cancer risk. In this study, we investigated how the concentration and composition of lignin in fiber influences the in vitro adsorption of primary...

  15. Cationic amphiphilic microfibrillated cellulose (MFC) for potential use for bile acid sorption.

    PubMed

    Zhu, Xuhai; Wen, Yangbing; Cheng, Dong; Li, Changmo; An, Xingye; Ni, Yonghao

    2015-11-01

    In this work, Micro-fibrillated Cellulose (MFC) was cationically modified by quaternary ammonium groups with different chemical structures aiming to improve the sorption capacity to bile acid. The in-vitro bile acid sorption was performed by investigating various factors, such as quaternary ammonium group content and length of its alkyl substituent of the modified cationic MFC (CMFC), ionic strength, initial concentration and hydrophobicity of bile acid. The results showed that the sorption behavior of the modified CMFC was strongly influenced by the quaternary ammonium group content and the lengths of its alkyl substituent, the sorption capacity for the modified CMFC with a C18 alkyl substituent, was approximately 50% of that of Cholestyramine. The experimental isotherm results were well fitted into the Temkin model. The effect of salts in the solution was smaller for the bile acid sorption onto the hydrophobic CMFC than the CMFC. It was also found that the binding capacity of CMFC was higher for more hydrophobic deoxycholate in comparison with cholate. PMID:26256387

  16. Metformin interferes with bile acid homeostasis through AMPK-FXR crosstalk.

    PubMed

    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

    2014-03-01

    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

  17. Shaping macrophages function and innate immunity by bile acids: mechanisms and implication in cholestatic liver diseases.

    PubMed

    Calmus, Yvon; Poupon, Raoul

    2014-10-01

    The liver is selectively enriched in innate immune cells, macrophages (Kupffer cells), natural killer, and natural killer T cells. These cells release an array of mediators with cytotoxic, pro- and anti-inflammatory, angiogenic, fibrogenic, and mitogenic activity that function to fight infections, limit tissue injury, and promote wound healing. The diverse activity of macrophages is mediated by distinct subpopulations that develop in response to signals within their microenvironment. Understanding the mechanisms and role of the microenvironment contributing to modulation of macrophage populations is crucial for comprehension of the pathophysiology of liver injury in diverse conditions. Several studies initiated in the 1990s have shown that bile acids modulate innate and adaptive immunity. In the last decade, bile acids turned into hormones and signalling molecules involved in many metabolic and inflammatory processes. Biological properties of bile acids are thought to be mediated mainly through activation of the nuclear receptor FXR, the membrane receptor TGR5, as well as PK, ERK, MAP kinases signalling pathways. FXR and TGR5 agonists are currently under development for clinical purpose. This review analyses the mechanisms involved in the immunomodulatory effects of bile acids on the macrophage and discuss their implications in the pathophysiology of cholestasis, primary biliary cirrhosis and primary sclerosing cholangitis. PMID:25176586

  18. Role of amidation in bile acid effect on DNA synthesis by regenerating mouse liver.

    PubMed

    Barbero, E R; Herrera, M C; Monte, M J; Serrano, M A; Marin, J J

    1995-06-01

    Effect of bile acids on DNA synthesis by the regenerating liver was investigated in mice in vivo after partial hepatectomy (PH). Radioactivity incorporation into DNA after [14C]thymidine intraperitoneal administration peaked at 48 h after PH. At this time a significant taurocholate-induced dose-dependent reduction in DNA synthesis without changes in total liver radioactivity content was found (half-maximal effect at approximately 0.1 mumol/g body wt). Effect of taurocholate (0.5 mumol/g body wt) was mimicked by chocolate, ursodeoxycholate, deoxycholate, dehydrocholate, tauroursodeoxycholate, taurochenodeoxycholate, and taurodeoxycholate. In contrast, chenodeoxycholate, glycocholate, glycochenodeoxycholate, glycoursodeoxycholate, glycodeoxycholate, 5 beta-cholestane, bromosulfophthalein, and free taurine lacked this effect. No relationship between hydrophobic-hydrophilic balance and inhibitory effect was observed. Analysis by high-performance liquid chromatography indicated that inhibition of thymidine incorporation into DNA was not accompanied by an accumulation of phosphorylated DNA precursors in the liver but rather by a parallel increase in nucleotide catabolism. Bile acid-induced modifications in DNA synthesis were observed in vivo even in the absence of changes in toxicity tests, which suggests that the inhibitory effect shared by most unconjugated and tauroconjugated bile acids but not by glycoconjugated bile acids should be accounted for by mechanisms other than nonselective liver cell injury. PMID:7611405

  19. 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

  20. 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

  1. Downregulation of p63 upon exposure to bile salts and acid in normal and cancer esophageal cells in culture.

    PubMed

    Roman, Sabine; Pétré, Aurélia; Thépot, Amélie; Hautefeuille, Agnès; Scoazec, Jean-Yves; Mion, François; Hainaut, Pierre

    2007-07-01

    p63 is a member of the p53 protein family that regulates differentiation and morphogenesis in epithelial tissues and is required for the formation of squamous epithelia. Barrett's mucosa is a glandular metaplasia of the squamous epithelium that develops in the lower esophagus in the context of chronic, gastroesophageal reflux and is considered as a precursor for adenocarcinoma. Normal or squamous cancer esophageal cells were exposed to deoxycholic acid (DCA, 50, 100, or 200 microM) and chenodeoxycholic and taurochenodeoxycholic acid at pH 5. p63 and cyclooxygenase-2 (COX-2) expressions were studied by Western blot and RT-PCR. DCA exposure at pH 5 led to a spectacular decrease in the levels of all isoforms of the p63 proteins. This decrease was observed within minutes of exposure, with a synergistic effect between DCA and acid. Within the same time frame, levels of p63 mRNA were relatively unaffected, whereas levels of COX-2, a marker of stress responses often induced in Barrett's mucosa, were increased. Similar results were obtained with chenodeoxycholic acid but not its taurine conjugate at pH 5. Proteasome inhibition by lactacystin or MG-132 partially blocked the decrease in p63, suggesting a posttranslational degradation mechanism. These results show that combined exposure to bile salt and acid downregulates a critical regulator of squamous differentiation, providing a mechanism to explain the replacement of squamous epithelium by a glandular metaplasia upon exposure of the lower esophagus to gastric reflux. PMID:17615180

  2. Steam cooking significantly improves in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage.

    PubMed

    Kahlon, Talwinder Singh; Chiu, Mei-Chen M; Chapman, Mary H

    2008-06-01

    Bile acid binding capacity has been related to the cholesterol-lowering potential of foods and food fractions. Lowered recirculation of bile acids results in utilization of cholesterol to synthesize bile acid and reduced fat absorption. Secondary bile acids have been associated with increased risk of cancer. Bile acid binding potential has been related to lowering the risk of heart disease and that of cancer. Previously, we have reported bile acid binding by several uncooked vegetables. However, most vegetables are consumed after cooking. How cooking would influence in vitro bile acid binding of various vegetables was investigated using a mixture of bile acids secreted in human bile under physiological conditions. Eight replicate incubations were conducted for each treatment simulating gastric and intestinal digestion, which included a substrate only, a bile acid mixture only, and 6 with substrate and bile acid mixture. Cholestyramine (a cholesterol-lowering, bile acid binding drug) was the positive control treatment and cellulose was the negative control. Relative to cholestyramine, in vitro bile acid binding on dry matter basis was for the collard greens, kale, and mustard greens, 13%; broccoli, 10%; Brussels sprouts and spinach, 8%; green bell pepper, 7%; and cabbage, 5%. These results point to the significantly different (P < or = .05) health-promoting potential of collard greens = kale = mustard greens > broccoli > Brussels sprouts = spinach = green bell pepper > cabbage as indicated by their bile acid binding on dry matter basis. Steam cooking significantly improved the in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage compared with previously observed bile acid binding values for these vegetables raw (uncooked). Inclusion of steam-cooked collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage in our daily diet as health-promoting vegetables should be emphasized. These green

  3. Microbiota and bile acid profiles in retinoic acid-primed mice that exhibit accelerated liver regeneration

    PubMed Central

    Liu, Hui-Xin; Hu, Ying; Wan, Yu-Jui Yvonne

    2016-01-01

    Background & Aims All-trans Retinoic acid (RA) regulates hepatic lipid and bile acid homeostasis. Similar to bile acid (BA), RA accelerates partial hepatectomy (PHx)-induced liver regeneration. Because there is a bidirectional regulatory relationship between gut microbiota and BA synthesis, we examined the effect of RA in altering the gut microbial population and BA composition and established their relationship with hepatic biological processes during the active phases of liver regeneration. Methods C57BL/6 mice were treated with RA orally followed by 2/3 PHx. The roles of RA in shifting gut microbiota and BA profiles as well as hepatocyte metabolism and proliferation were studied. Results RA-primed mice exhibited accelerated hepatocyte proliferation revealed by higher numbers of Ki67-positive cells compared to untreated mice. Firmicutes and Bacteroidetes phyla dominated the gut microbial community (>85%) in both control and RA-primed mice after PHx. RA reduced the ratio of Firmicutes to Bacteroidetes, which was associated with a lean phenotype. Consistently, RA-primed mice lacked transient lipid accumulation normally found in regenerating livers. In addition, RA altered BA homeostasis and shifted BA profiles by increasing the ratio of hydrophilic to hydrophobic BAs in regenerating livers. Accordingly, metabolic regulators fibroblast growth factor 21, Sirtuin1, and their downstream targets AMPK and ERK1/2 were more robustly activated in RA-primed than unprimed regenerating livers. Conclusions Priming mice with RA resulted in a lean microbiota composition and hydrophilic BA profiles, which were associated with facilitated metabolism and enhanced cell proliferation. PMID:26701854

  4. Chemoprevention of N-methylnitrosourea-induced colon carcinogenesis by ursodeoxycholic acid-5-aminosalicylic acid conjugate in F344 rats.

    PubMed

    Narisawa, Tomio; Fukaura, Yoko; Takeba, Naomi; Nakai, Keiko

    2002-02-01

    Bile acids enhance colon carcinogenesis in animal models, whereas ursodeoxycholic acid (UDCA) suppresses it. Nonsteroid anti-inflammatory drugs prevent colon cancer development in animals and humans. The aim of the present study was to explore the inhibitory effect of UDCA conjugate with 5-aminosalicylic acid (5-ASA), UDCA-5-ASA conjugate (UDCA-5-ASA), against colon carcinogenesis in rats. One-hundred-and-twenty-nine 7-week-old F344 rats received an intrarectal instillation of 2 mg of N-methylnitrosourea 3 times a week for 3 weeks, and were fed a 0% (control), 0.11% or 0.02% UDCA-5-ASA-, 0.08% UDCA- or 0.03% 5-ASA-supplemented diet for the next 27 weeks. The test diets contained an equimolar amount of a test agent, 2.0 mmol/kg diet, except for the 0.02% UDCA-5-ASA diet. The tumor incidence and the mean number of tumors/rat at week 30 were significantly lower and smaller in the UDCA-5-ASA diet groups, 48% and 0.7 in both, and marginally lower in the UDCA and 5-ASA diet groups, 56% and 0.9, and 64% and 0.8, compared to the control group, 83% and 1.3. All the tumors were polypoid in shape, and most of them were differentiated adenocarcinomas restricted to the mucosa or submucosa. An analysis by HPLC for bile acids and 5-ASA in the feces and serum collected at week 30 showed that one-half of ingested UDCA-5-ASA was cleaved into UDCA and 5-ASA in the colon. Thus, the two moieties may have independently affected the promotion stage of carcinogenesis. PMID:11856477

  5. Constitutive androstane receptor-mediated changes in bile acid composition contributes to hepatoprotection from lithocholic acid-induced liver injury in mice.

    PubMed

    Beilke, Lisa D; Aleksunes, Lauren M; Holland, Ricky D; Besselsen, David G; Beger, Rick D; Klaassen, Curtis D; Cherrington, Nathan J

    2009-05-01

    Pharmacological activation of the constitutive androstane receptor (CAR) protects the liver during cholestasis. The current study evaluates how activation of CAR influences genes involved in bile acid biosynthesis as a mechanism of hepatoprotection during bile acid-induced liver injury. CAR activators phenobarbital (PB) and 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) or corn oil (CO) were administered to C57BL/6 wild-type (WT) and CAR knockout (CAR-null) mice before and during induction of intrahepatic cholestasis using the secondary bile acid, lithocholic acid (LCA). In LCA-treated WT and all the CAR-null groups (excluding controls), histology revealed severe multifocal necrosis. This pathology was absent in WT mice pretreated with PB and TCPOBOP, indicating CAR-dependent hepatoprotection. Decreases in total hepatic bile acids and hepatic monohydroxy, dihydroxy, and trihydroxy bile acids in PB- and TCPOBOP-pretreated WT mice correlated with hepatoprotection. In comparison, concentrations of monohydroxylated and dihydroxylated bile acids were increased in all the treated CAR-null mice compared with CO controls. Along with several other enzymes (Cyp7b1, Cyp27a1, Cyp39a1), Cyp8b1 expression was increased in hepatoprotected mice, which could be suggestive of a shift in the bile acid biosynthesis pathway toward the formation of less toxic bile acids. In CAR-null mice, these changes in gene expression were not different among treatment groups. These results suggest CAR mediates a shift in bile acid biosynthesis toward the formation of less toxic bile acids, as well as a decrease in hepatic bile acid concentrations. We propose that these combined CAR-mediated effects may contribute to the hepatoprotection observed during LCA-induced liver injury. PMID:19196849

  6. Receptor-mediated uptake of low density lipoprotein stimulates bile acid synthesis by cultured rat hepatocytes

    SciTech Connect

    Junker, L.H.; Davis, R.A. )

    1989-12-01

    The cellular mechanisms responsible for the lipoprotein-mediated stimulation of bile acid synthesis in cultured rat hepatocytes were investigated. Adding 280 micrograms/ml of cholesterol in the form of human or rat low density lipoprotein (LDL) to the culture medium increased bile acid synthesis by 1.8- and 1.6-fold, respectively. As a result of the uptake of LDL, the synthesis of (14C)cholesterol from (2-14C)acetate was decreased and cellular cholesteryl ester mass was increased. Further studies demonstrated that rat apoE-free LDL and apoE-rich high density lipoprotein (HDL) both stimulated bile acid synthesis 1.5-fold, as well as inhibited the formation of (14C)cholesterol from (2-14C)acetate. Reductive methylation of LDL blocked the inhibition of cholesterol synthesis, as well as the stimulation of bile acid synthesis, suggesting that these processes require receptor-mediated uptake. To identify the receptors responsible, competitive binding studies using 125I-labeled apoE-free LDL and 125I-labeled apoE-rich HDL were performed. Both apoE-free LDL and apoE-rich HDL displayed an equal ability to compete for binding of the other, suggesting that a receptor or a group of receptors that recognizes both apolipoproteins is involved. Additional studies show that hepatocytes from cholestyramine-treated rats displayed 2.2- and 3.4-fold increases in the binding of apoE-free LDL and apoE-rich HDL, respectively. These data show for the first time that receptor-mediated uptake of LDL by the liver is intimately linked to processes activating bile acid synthesis.

  7. Effect of various antibiotics on modulation of intestinal microbiota and bile acid profile in mice

    SciTech Connect

    Zhang, Youcai; Limaye, Pallavi B.; Renaud, Helen J.; Klaassen, Curtis D.

    2014-06-01

    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 profiles 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.

  8. Ciliary subcellular localization of TGR5 determines the cholangiocyte functional response to bile acid signaling

    PubMed Central

    Masyuk, Anatoliy I.; Huang, Bing Q.; Radtke, Brynn N.; Gajdos, Gabriella B.; Splinter, Patrick L.; Masyuk, Tatyana V.; Gradilone, Sergio A.

    2013-01-01

    TGR5, the G protein-coupled bile acid receptor that transmits bile acid signaling into a cell functional response via the intracellular cAMP signaling pathway, is expressed in human and rodent cholangiocytes. However, detailed information on the localization and function of cholangiocyte TGR5 is limited. We demonstrated that in human (H69 cells) and rat cholangiocytes, TGR5 is localized to multiple, diverse subcellular compartments, with its strongest expression on the apical plasma, ciliary, and nuclear membranes. To evaluate the relationship between ciliary TGR5 and the cholangiocyte functional response to bile acid signaling, we used a model of ciliated and nonciliated H69 cells and demonstrated that TGR5 agonists induce opposite changes in cAMP and ERK levels in cells with and without primary cilia. The cAMP level was increased in nonciliated cholangiocytes but decreased in ciliated cells. In contrast, ERK signaling was induced in ciliated cholangiocytes but suppressed in cells without cilia. TGR5 agonists inhibited proliferation of ciliated cholangiocytes but activated proliferation of nonciliated cells. The observed differential effects of TGR5 agonists were associated with the coupling of TGR5 to Gαi protein in ciliated cells and Gαs protein in nonciliated cholangiocytes. The functional responses of nonciliated and ciliated cholangiocytes to TGR5-mediated bile acid signaling may have important pathophysiological significance in cilia-related liver disorders (i.e., cholangiociliopathies), such as polycystic liver disease. In summary, TGR5 is expressed on diverse cholangiocyte compartments, including a primary cilium, and its ciliary localization determines the cholangiocyte functional response to bile acid signaling. PMID:23578785

  9. Ciliary subcellular localization of TGR5 determines the cholangiocyte functional response to bile acid signaling.

    PubMed

    Masyuk, Anatoliy I; Huang, Bing Q; Radtke, Brynn N; Gajdos, Gabriella B; Splinter, Patrick L; Masyuk, Tatyana V; Gradilone, Sergio A; LaRusso, Nicholas F

    2013-06-01

    TGR5, the G protein-coupled bile acid receptor that transmits bile acid signaling into a cell functional response via the intracellular cAMP signaling pathway, is expressed in human and rodent cholangiocytes. However, detailed information on the localization and function of cholangiocyte TGR5 is limited. We demonstrated that in human (H69 cells) and rat cholangiocytes, TGR5 is localized to multiple, diverse subcellular compartments, with its strongest expression on the apical plasma, ciliary, and nuclear membranes. To evaluate the relationship between ciliary TGR5 and the cholangiocyte functional response to bile acid signaling, we used a model of ciliated and nonciliated H69 cells and demonstrated that TGR5 agonists induce opposite changes in cAMP and ERK levels in cells with and without primary cilia. The cAMP level was increased in nonciliated cholangiocytes but decreased in ciliated cells. In contrast, ERK signaling was induced in ciliated cholangiocytes but suppressed in cells without cilia. TGR5 agonists inhibited proliferation of ciliated cholangiocytes but activated proliferation of nonciliated cells. The observed differential effects of TGR5 agonists were associated with the coupling of TGR5 to Gαi protein in ciliated cells and Gαs protein in nonciliated cholangiocytes. The functional responses of nonciliated and ciliated cholangiocytes to TGR5-mediated bile acid signaling may have important pathophysiological significance in cilia-related liver disorders (i.e., cholangiociliopathies), such as polycystic liver disease. In summary, TGR5 is expressed on diverse cholangiocyte compartments, including a primary cilium, and its ciliary localization determines the cholangiocyte functional response to bile acid signaling. PMID:23578785

  10. Effect of 3-hydroxy-3-methylglutaric acid administration on bile lipid composition in humans.

    PubMed

    Di Padova, C; Di Padova, F; Buzzetti, M; Tritapepe, R

    1984-09-01

    The effects of the lipid-lowering agent 3-hydroxy-3-methylglutaric acid (HMGA) on serum lipids and on biliary lipid composition were evaluated in a double-blind, placebo-controlled study in normolipidemic volunteers. After 4 weeks of HMGA administration (1 g three times a day orally) serum total cholesterol showed a significant decrease with regard to both pretreatment values and corresponding values of controls. The bile lipid molar percentage composition and the cholesterol saturation index showed no modification after HMGA and did not differ from the values obtained in the placebo group. These findings indicate that HMGA exerts no adverse effects on bile lipid composition in humans, differing from other hypolipidemic drugs currently in clinical use, which increase the bile cholesterol saturation index. PMID:6083597

  11. Effect of Wheat Dietary Fiber Particle Size during Digestion In Vitro on Bile Acid, Faecal Bacteria and Short-Chain Fatty Acid Content.

    PubMed

    Dziedzic, Krzysztof; Szwengiel, Artur; Górecka, Danuta; Gujska, Elżbieta; Kaczkowska, Joanna; Drożdżyńska, Agnieszka; Walkowiak, Jarosław

    2016-06-01

    The influence of bile acid concentration on the growth of Bifidobacterium spp. and Lactobacillus spp. bacteria was demonstrated. Exposing these bacteria to the environment containing bile acid salts, and very poor in nutrients, leads to the disappearance of these microorganisms due to the toxic effect of bile acids. A multidimensional analysis of data in the form of principal component analysis indicated that lactic acid bacteria bind bile acids and show antagonistic effect on E. coli spp. bacteria. The growth in E. coli spp. population was accompanied by a decline in the population of Bifidobacterium spp. and Lactobacillus spp. with a simultaneous reduction in the concentration of bile acids. This is direct proof of acid binding ability of the tested lactic acid bacteria with respect to cholic acid, lithocholic acid and deoxycholic acid. This research demonstrated that the degree of fineness of wheat dietary fibre does not affect the sorption of bile acids and growth of some bacteria species; however, it has an impact on the profile of synthesized short-chained fatty acids. During the digestion of a very fine wheat fibre fraction (WF 90), an increase in the concentration of propionic and butyric acids, as compared with the wheat fiber fraction of larger particles - WF 500, was observed. Our study suggested that wheat fibre did not affect faecal bacteria growth, however, we observed binding of bile acids by Bifidobacterium spp. and Lactobacillus spp. PMID:26924312

  12. A Biochemical Abnormality in Cerebrotendinous Xanthomatosis IMPAIRMENT OF BILE ACID BIOSYNTHESIS ASSOCIATED WITH INCOMPLETE DEGRADATION OF THE CHOLESTEROL SIDE CHAIN

    PubMed Central

    Setoguchi, T.; Salen, Gerald; Tint, G. S.; Mosbach, E. H.

    1974-01-01

    Bile acid production in cerebrotendinous xanthomatosis (CTX) is subnormal, yet the activity of cholesterol 7α-hydroxylase, the rate-determining enzyme of bile acid synthesis, is elevated. To explain this discrepancy, bile acid precursors were sought in bile and feces of three CTX subjects. Over 10% of the total sterols excreted in bile and feces consisted of compounds more polar than cholesterol. Chromatographic analysis of the polar fractions in conjunction with gasliquid chromatography (GLC)-mass spectrometry indicated two major constituents, 5β-cholestane-3α,7α,12α,25-tetrol and 5β-cholestane-3α,7α,12α,24ξ,25-pentol. After i.v. injection of [4-14C]cholesterol both bile alcohols were radioactive proving that they were derived from cholesterol. The accumulation of alcohols hydroxylated at C-25 and C-24,25 suggests that decreased bile acid synthesis in CTX results from impaired oxidation of the cholesterol side chain. This finding and the virtual absence of intermediates hydroxylated at C-26 indicate that current views of the major pathway of bile acid synthesis may require revision. PMID:4825231

  13. Bile acid binding capacity of fish protein hydrolysates from discard species of the West Mediterranean Sea.

    PubMed

    Pérez-Gálvez, Raúl; García-Moreno, Pedro J; Morales-Medina, Rocío; Guadix, Antonio; Guadix, Emilia M

    2015-04-01

    Fish protein hydrolysates (FPH), produced from the six main discard species from the West Mediterranean Sea (sardine, horse mackerel, axillary seabream, bogue, small-spotted catshark and blue whiting) were tested for their bile acid binding capacity. This capacity is directly linked to the ability to inhibit bile reabsorption in the ileum and therefore to lower cholesterol levels in the bloodstream. From each species, FPH were obtained by three different enzymatic treatments employing two serine endoproteases (subtilisin and trypsin) sequentially or in combination. The results show statistically significant differences among the fish species, attaining interesting average values of bile acid binding capacity for blue whiting (27.32% relative to cholestyramine on an equal protein basis) and horse mackerel (27.42% relative to cholestyramine on an equal protein basis). The enzymatic treatments did not significantly affect the ability of a given species to bind bile acids. These results are similar to other protein sources, such as soy protein or casein, of proven hypocholesterolemic effect. It can be concluded that fish protein hydrolysates from these discard species are suitable as ingredients in the formulation of cholesterol-lowering supplements. PMID:25756593

  14. Bile acid receptor TGR5, NADPH Oxidase NOX5-S and CREB Mediate Bile Acid-Induced DNA Damage In Barrett’s Esophageal Adenocarcinoma Cells

    PubMed Central

    Li, Dan; Cao, Weibiao

    2016-01-01

    The mechanisms whereby bile acid reflux may accelerate the progression from Barrett’s esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. In this study we found that bile acid taurodeoxycholic acid (TDCA) significantly increased the tail moment (TM) and histone H2AX phosphorylation in FLO-1 EA cells, an increase which was significantly decreased by knockdown of TGR5. Overexpression of TGR5 significantly increased TDCA-induced TM increase and H2AX phosphorylation. In addition, NADPH oxidase inhibitor diphenylene iodonium significantly inhibited the TDCA-induced increase in TM and H2AX phosphorylation. TDCA-induced increase in TM and H2AX phosphorylation was significantly decreased by knockdown of NOX5-S and overexpression of NOX5-S significantly increased TDCA-induced increase in the tail moment and H2AX phosphorylation. Furthermore, TDCA significantly increased cAMP response element binding protein (CREB) phosphorylation in FLO-1 cells. Knockdown of CREB significantly decreased TDCA-induced increase in NOX5-S mRNA and the tail moment. Conversely, overexpression of CREB significantly increased TDCA-induced TM increase. We conclude that TDCA-induced DNA damage may depend on the activation of TGR5, CREB and NOX5-S. It is possible that in Barrett’s patients bile acids may activate NOX5-S and increase reactive oxygen species (ROS) production via activation of TGR5 and CREB. NOX5-S-derived ROS may cause DNA damage, thereby contributing to the progression from BE to EA. PMID:27511066

  15. Bile acid receptor TGR5, NADPH Oxidase NOX5-S and CREB Mediate Bile Acid-Induced DNA Damage In Barrett's Esophageal Adenocarcinoma Cells.

    PubMed

    Li, Dan; Cao, Weibiao

    2016-01-01

    The mechanisms whereby bile acid reflux may accelerate the progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. In this study we found that bile acid taurodeoxycholic acid (TDCA) significantly increased the tail moment (TM) and histone H2AX phosphorylation in FLO-1 EA cells, an increase which was significantly decreased by knockdown of TGR5. Overexpression of TGR5 significantly increased TDCA-induced TM increase and H2AX phosphorylation. In addition, NADPH oxidase inhibitor diphenylene iodonium significantly inhibited the TDCA-induced increase in TM and H2AX phosphorylation. TDCA-induced increase in TM and H2AX phosphorylation was significantly decreased by knockdown of NOX5-S and overexpression of NOX5-S significantly increased TDCA-induced increase in the tail moment and H2AX phosphorylation. Furthermore, TDCA significantly increased cAMP response element binding protein (CREB) phosphorylation in FLO-1 cells. Knockdown of CREB significantly decreased TDCA-induced increase in NOX5-S mRNA and the tail moment. Conversely, overexpression of CREB significantly increased TDCA-induced TM increase. We conclude that TDCA-induced DNA damage may depend on the activation of TGR5, CREB and NOX5-S. It is possible that in Barrett's patients bile acids may activate NOX5-S and increase reactive oxygen species (ROS) production via activation of TGR5 and CREB. NOX5-S-derived ROS may cause DNA damage, thereby contributing to the progression from BE to EA. PMID:27511066

  16. In vitro bile acid binding and short-chain fatty acid profile of flax fiber and ethanol co-products.

    PubMed

    Fodje, Adele M L; Chang, Peter R; Leterme, Pascal

    2009-10-01

    Fibers from flaxseed and co-products from ethanol production could be potential sources of dietary fiber in human diet. In vitro fermentation and bile acid binding models were used to investigate the metabolic effects of lignaMax (Bioriginal Food and Science Corp., Saskatoon, SK, Canada) flax meal, spent flax meal, soluble flax gum, wheat insoluble fiber (WIF), and rye insoluble fiber (RIF). Wheat and rye bran were used as reference samples. Bile acid binding of substrates was analysed at taurocholate ([(14)C]taurocholate) concentration of 12.5 mM. Soluble flax gum showed the highest bile acid binding (0.57 micromol/mg of fiber) (P bile acid binding between wheat bran (0.2 micromol/mg of fiber) and WIF (0.26 micromol/mg of fiber). RIF had higher (P bile acid binding (0.20 micromol/mg of fiber) than rye bran (0.13 micromol/mg of fiber). Substrates were hydrolyzed and incubated with pig fecal samples. Short-chain fatty acid (SCFA) profile and gas accumulation (G(f)) were compared. Soluble flax gum generated the highest amount of acetic and propionic acids. SCFA profiles of wheat/rye brans and WIF/RIF were similar (except for butyric acid). G(f) for soluble flax gum was greater (P < .001) than that of spent flax meal. G(f) values of the wheat samples were similar, whereas the G(f) of the rye bran was higher (P < .001) than that of RIF. Fractional degradation rate (micro(t = T/2)) (P < .001) was also recorded. The highest mu(t = T/2) was observed for the soluble flax gum. Oil-depleted flaxseed fractions and WIF/RIF (co-products from ethanol production) could be potential sources of dietary fiber in human nutrition. PMID:19857071

  17. Bile resistance mechanisms in Lactobacillus and Bifidobacterium

    PubMed Central

    Ruiz, Lorena; Margolles, Abelardo; Sánchez, Borja

    2013-01-01

    Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. Most of the probiotic bacteria currently available in the market belong to the genera Lactobacillus and Bifidobacterium, and specific health-promoting activities, such as treatment of diarrhea or amelioration of gastrointestinal discomfort, have been attributed to them. In order to be able to survive the gastrointestinal transit and transiently colonize our gut, these bacteria must be able to counteract the deleterious action of bile salts, which are the main components of bile. Bile salts are detergent-like biological substances synthesized in the liver from cholesterol. Host enzymes conjugate the newly synthesized free bile acids in the liver with the amino acids glycine or taurine, generating conjugated bile salts. These compounds are stored in the gall bladder and they are released into the duodenum during digestion to perform their physiological function, which is the solubilization of fat coming from diet. These bile salts possess strong antimicrobial activity, since they are able to disorganize the structure of the cell membrane, as well as trigger DNA damage. This means that bacteria inhabiting our intestinal tract must have intrinsic resistance mechanisms to cope with bile salts. To do that, Lactobacillus and Bifidobacterium display a variety of proteins devoted to the efflux of bile salts or protons, to modify sugar metabolism or to prevent protein misfolding. In this manuscript, we review and discuss specific bile resistance mechanisms, as well as the processes responsible for the adaptation of bifidobacteria and lactobacilli to bile. PMID:24399996

  18. Bile resistance mechanisms in Lactobacillus and Bifidobacterium.

    PubMed

    Ruiz, Lorena; Margolles, Abelardo; Sánchez, Borja

    2013-01-01

    Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. Most of the probiotic bacteria currently available in the market belong to the genera Lactobacillus and Bifidobacterium, and specific health-promoting activities, such as treatment of diarrhea or amelioration of gastrointestinal discomfort, have been attributed to them. In order to be able to survive the gastrointestinal transit and transiently colonize our gut, these bacteria must be able to counteract the deleterious action of bile salts, which are the main components of bile. Bile salts are detergent-like biological substances synthesized in the liver from cholesterol. Host enzymes conjugate the newly synthesized free bile acids in the liver with the amino acids glycine or taurine, generating conjugated bile salts. These compounds are stored in the gall bladder and they are released into the duodenum during digestion to perform their physiological function, which is the solubilization of fat coming from diet. These bile salts possess strong antimicrobial activity, since they are able to disorganize the structure of the cell membrane, as well as trigger DNA damage. This means that bacteria inhabiting our intestinal tract must have intrinsic resistance mechanisms to cope with bile salts. To do that, Lactobacillus and Bifidobacterium display a variety of proteins devoted to the efflux of bile salts or protons, to modify sugar metabolism or to prevent protein misfolding. In this manuscript, we review and discuss specific bile resistance mechanisms, as well as the processes responsible for the adaptation of bifidobacteria and lactobacilli to bile. PMID:24399996

  19. Serum bile acids are higher in humans with prior gastric bypass: potential contribution to improved glucose and lipid metabolism.

    PubMed

    Patti, Mary-Elizabeth; Houten, Sander M; Bianco, Antonio C; Bernier, Raquel; Larsen, P Reed; Holst, Jens J; Badman, Michael K; Maratos-Flier, Eleftheria; Mun, Edward C; Pihlajamaki, Jussi; Auwerx, Johan; Goldfine, Allison B

    2009-09-01

    The multifactorial mechanisms promoting weight loss and improved metabolism following Roux-en-Y gastric bypass (GB) surgery remain incompletely understood. Recent rodent studies suggest that bile acids can mediate energy homeostasis by activating the G-protein coupled receptor TGR5 and the type 2 thyroid hormone deiodinase. Altered gastrointestinal anatomy following GB could affect enterohepatic recirculation of bile acids. We assessed whether circulating bile acid concentrations differ in patients who previously underwent GB, which might then contribute to improved metabolic homeostasis. We performed cross-sectional analysis of fasting serum bile acid composition and both fasting and post-meal metabolic variables, in three subject groups: (i) post-GB surgery (n = 9), (ii) without GB matched to preoperative BMI of the index cohort (n = 5), and (iii) without GB matched to current BMI of the index cohort (n = 10). Total serum bile acid concentrations were higher in GB (8.90 +/- 4.84 micromol/l) than in both overweight (3.59 +/- 1.95, P = 0.005, Ov) and severely obese (3.86 +/- 1.51, P = 0.045, MOb). Bile acid subfractions taurochenodeoxycholic, taurodeoxycholic, glycocholic, glycochenodeoxycholic, and glycodeoxycholic acids were all significantly higher in GB compared to Ov (P < 0.05). Total bile acids were inversely correlated with 2-h post-meal glucose (r = -0.59, P < 0.003) and fasting triglycerides (r = -0.40, P = 0.05), and positively correlated with adiponectin (r = -0.48, P < 0.02) and peak glucagon-like peptide-1 (GLP-1) (r = 0.58, P < 0.003). Total bile acids strongly correlated inversely with thyrotropic hormone (TSH) (r = -0.57, P = 0.004). Together, our data suggest that altered bile acid levels and composition may contribute to improved glucose and lipid metabolism in patients who have had GB. PMID:19360006

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

    SciTech Connect

    Schiller, L.R.; Hogan, R.B.; Morawski, S.G.; Santa Ana, C.A.; Bern, M.J.; Norgaard, R.P.; Bo-Linn, G.W.; Fordtran, J.S.

    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 of 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.

  1. Disulfide bridge regulates ligand-binding site selectivity in liver bile acid-binding proteins.

    PubMed

    Cogliati, Clelia; Tomaselli, Simona; Assfalg, Michael; Pedò, Massimo; Ferranti, Pasquale; Zetta, Lucia; Molinari, Henriette; Ragona, Laura

    2009-10-01

    Bile acid-binding proteins (BABPs) are cytosolic lipid chaperones that play central roles in driving bile flow, as well as in the adaptation to various pathological conditions, contributing to the maintenance of bile acid homeostasis and functional distribution within the cell. Understanding the mode of binding of bile acids with their cytoplasmic transporters is a key issue in providing a model for the mechanism of their transfer from the cytoplasm to the nucleus, for delivery to nuclear receptors. A number of factors have been shown to modulate bile salt selectivity, stoichiometry, and affinity of binding to BABPs, e.g. chemistry of the ligand, protein plasticity and, possibly, the formation of disulfide bridges. Here, the effects of the presence of a naturally occurring disulfide bridge on liver BABP ligand-binding properties and backbone dynamics have been investigated by NMR. Interestingly, the disulfide bridge does not modify the protein-binding stoichiometry, but has a key role in modulating recognition at both sites, inducing site selectivity for glycocholic and glycochenodeoxycholic acid. Protein conformational changes following the introduction of a disulfide bridge are small and located around the inner binding site, whereas significant changes in backbone motions are observed for several residues distributed over the entire protein, both in the apo form and in the holo form. Site selectivity appears, therefore, to be dependent on protein mobility rather than being governed by steric factors. The detected properties further establish a parallelism with the behaviour of human ileal BABP, substantiating the proposal that BABPs have parallel functions in hepatocytes and enterocytes. PMID:19754879

  2. Molecular mechanisms underlying bile acid-stimulated glucagon-like peptide-1 secretion

    PubMed Central

    Parker, HE; Wallis, K; le Roux, CW; Wong, KY; Reimann, F; Gribble, FM

    2012-01-01

    BACKGROUND AND PURPOSE The glucagon-like peptides GLP-1 and GLP-2 are secreted from enteroendocrine L-cells following nutrient ingestion. Drugs that increase activity of the GLP-1 axis are highly successful therapies for type 2 diabetes, and boosting L-cell secretion is a potential strategy for future diabetes treatment. The aim of the present study was to further our understanding of the bile acid receptor GPBA (TGR5), an L-cell target currently under therapeutic exploration. EXPERIMENTAL APPROACH GLUTag cells and mixed primary murine intestinal cultures were exposed to bile acids and a specific agonist, GPBAR-A. Secretion was measured using hormone assays and intracellular calcium and cAMP responses were monitored using real-time imaging techniques. KEY RESULTS Bile acid-triggered GLP-1 secretion from GLUTag cells was GPBA-dependent, as demonstrated by its abolition following tgr5 siRNA transfection. Bile acids and GPBAR-A increased GLP-1 secretion from intestinal cultures, with evidence for synergy between the effects of glucose and GPBA activation. Elevation of cAMP was observed following GPBA activation in individual GLUTag cells. Direct calcium responses to GPBAR-A were small, but in the presence of the agonist, a subpopulation of cells that was previously poorly glucose-responsive exhibited robust glucose responses. In vivo, increased delivery of bile to more distal regions of the ileum augmented L-cell stimulation. CONCLUSIONS AND IMPLICATIONS GPBA signalling in L-cells involves rapid elevation of cAMP, and enhanced calcium and secretory responses to glucose. Modulation of this receptor therapeutically may be an attractive strategy to enhance GLP-1 secretion and achieve better glycaemic control in diabetic patients. PMID:21718300

  3. Changes in Colonic Bile Acid Composition following Fecal Microbiota Transplantation Are Sufficient to Control Clostridium difficile Germination and Growth

    PubMed Central

    Weingarden, Alexa R.; Dosa, Peter I.; DeWinter, Erin; Steer, Clifford J.; Shaughnessy, Megan K.; Johnson, James R.; Khoruts, Alexander; Sadowsky, Michael J.

    2016-01-01

    Fecal microbiota transplantation (FMT) is a highly effective therapy for recurrent Clostridium difficile infection (R-CDI), but its mechanisms remain poorly understood. Emerging evidence suggests that gut bile acids have significant influence on the physiology of C. difficile, and therefore on patient susceptibility to recurrent infection. We analyzed spore germination of 10 clinical C. difficile isolates exposed to combinations of bile acids present in patient feces before and after FMT. Bile acids at concentrations found in patients’ feces prior to FMT induced germination of C. difficile, although with variable potency across different strains. However, bile acids at concentrations found in patients after FMT did not induce germination and inhibited vegetative growth of all C. difficile strains. Sequencing of the newly identified germinant receptor in C. difficile, CspC, revealed a possible correspondence of variation in germination responses across isolates with mutations in this receptor. This may be related to interstrain variability in spore germination and vegetative growth in response to bile acids seen in this and other studies. These results support the idea that intra-colonic bile acids play a key mechanistic role in the success of FMT, and suggests that novel therapeutic alternatives for treatment of R-CDI may be developed by targeted manipulation of bile acid composition in the colon. PMID:26789728

  4. Changes in Colonic Bile Acid Composition following Fecal Microbiota Transplantation Are Sufficient to Control Clostridium difficile Germination and Growth.

    PubMed

    Weingarden, Alexa R; Dosa, Peter I; DeWinter, Erin; Steer, Clifford J; Shaughnessy, Megan K; Johnson, James R; Khoruts, Alexander; Sadowsky, Michael J

    2016-01-01

    Fecal microbiota transplantation (FMT) is a highly effective therapy for recurrent Clostridium difficile infection (R-CDI), but its mechanisms remain poorly understood. Emerging evidence suggests that gut bile acids have significant influence on the physiology of C. difficile, and therefore on patient susceptibility to recurrent infection. We analyzed spore germination of 10 clinical C. difficile isolates exposed to combinations of bile acids present in patient feces before and after FMT. Bile acids at concentrations found in patients' feces prior to FMT induced germination of C. difficile, although with variable potency across different strains. However, bile acids at concentrations found in patients after FMT did not induce germination and inhibited vegetative growth of all C. difficile strains. Sequencing of the newly identified germinant receptor in C. difficile, CspC, revealed a possible correspondence of variation in germination responses across isolates with mutations in this receptor. This may be related to interstrain variability in spore germination and vegetative growth in response to bile acids seen in this and other studies. These results support the idea that intra-colonic bile acids play a key mechanistic role in the success of FMT, and suggests that novel therapeutic alternatives for treatment of R-CDI may be developed by targeted manipulation of bile acid composition in the colon. PMID:26789728

  5. Design and Evaluation of a Novel Trifluorinated Imaging Agent for Assessment of Bile Acid Transport Using Fluorine Magnetic Resonance Imaging

    PubMed Central

    Vivian, Diana; Cheng, Kunrong; Khurana, Sandeep; Xu, Su; Dawson, Paul A.; Raufman, Jean-Pierre; Polli, James E.

    2014-01-01

    Previously, we developed a trifluorinated bile acid, CA-lys-TFA, with the objective of noninvasively assessing bile acid transport in vivo using 19F magnetic resonance imaging (MRI). CA-lys-TFA was successfully imaged in the mouse gallbladder, but was susceptible to deconjugation in vitro by choloylglycine hydrolase (CGH), a bacterial bile acid deconjugating enzyme found in the terminal ileum and colon. The objective of the present study was to develop a novel trifluorinated bile acid resistant to deconjugation by CGH. CA-sar-TFMA was designed, synthesized, and tested for in vitro transport properties, stability, imaging properties, and its ability to differentially accumulate in the gallbladders of normal mice, compared with mice with known impaired bile acid transport (deficient in the apical sodium-dependent bile acid transporter, ASBT). CA-sar-TFMA was a potent inhibitor and substrate of ASBT and the Na+/taurocholate cotransporting polypeptide. Stability was favorable in all conditions tested, including the presence of CGH. CA-sar-TFMA was successfully imaged and accumulated at 16.1-fold higher concentrations in gallbladders from wild-type mice compared with those from Asbt-deficient mice. Our results support the potential of using MRI with CA-sar-TFMA as a noninvasive method to assess bile acid transport in vivo. PMID:25196788

  6. Slc10a2-null mice uncover colon cancer-promoting actions of endogenous fecal bile acids.

    PubMed

    Raufman, Jean-Pierre; Dawson, Paul A; Rao, Anuradha; Drachenberg, Cinthia B; Heath, Jonathon; Shang, Aaron C; Hu, Shien; Zhan, Min; Polli, James E; Cheng, Kunrong

    2015-10-01

    Although epidemiological evidence in humans and bile acid feeding studies in rodents implicate bile acids as tumor promoters, the role of endogenous bile acids in colon carcinogenesis remains unclear. In this study, we exploited mice deficient in the ileal apical sodium-dependent bile acid transporter (ASBT, encoded by SLC10A2) in whom fecal bile acid excretion is augmented more than 10-fold. Wild-type and Asbt-deficient (Slc10a2 (-/-) ) male mice were treated with azoxymethane (AOM) alone to examine the development of aberrant crypt foci, the earliest histological marker of colon neoplasia and a combination of AOM and dextran sulfate sodium to induce colon tumor formation. Asbt-deficient mice exhibited a 54% increase in aberrant crypt foci, and 70 and 59% increases in colon tumor number and size, respectively. Compared to littermate controls, Asbt-deficient mice had a striking, 2-fold increase in the number of colon adenocarcinomas. Consistent with previous studies demonstrating a role for muscarinic and epidermal growth factor receptor signaling in bile acid-induced colon neoplasia, increasing bile acid malabsorption was associated with M3 muscarinic and epidermal growth factor receptor expression, and activation of extracellular signal-related kinase, a key post-receptor signaling molecule. PMID:26210740

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

    SciTech Connect

    Yamazaki, Makoto; Miyake, Manami; Sato, Hiroko; Masutomi, Naoya; Tsutsui, Naohisa; Adam, Klaus-Peter; Alexander, Danny C.; Lawton, Kay A.; Milburn, Michael V.; Ryals, John A.; Wulff, Jacob E.; Guo, Lining

    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 metabolites 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

  8. Natural Bile Acids and Synthetic Analogues Modulate Large Conductance Ca2+-activated K+ (BKCa) Channel Activity in Smooth Muscle Cells

    PubMed Central

    Dopico, Alejandro M.; Walsh, John V.; Singer, Joshua J.

    2002-01-01

    Bile acids have been reported to produce relaxation of smooth muscle both in vitro and in vivo. The cellular mechanisms underlying bile acid–induced relaxation are largely unknown. Here we demonstrate, using patch-clamp techniques, that natural bile acids and synthetic analogues reversibly increase BKCa channel activity in rabbit mesenteric artery smooth muscle cells. In excised inside-out patches bile acid–induced increases in channel activity are characterized by a parallel leftward shift in the activity-voltage relationship. This increase in BKCa channel activity is not due to Ca2+-dependent mechanism(s) or changes in freely diffusible messengers, but to a direct action of the bile acid on the channel protein itself or some closely associated component in the cell membrane. For naturally occurring bile acids, the magnitude of bile acid–induced increase in BKCa channel activity is inversely related to the number of hydroxyl groups in the bile acid molecule. By using synthetic analogues, we demonstrate that such increase in activity is not affected by several chemical modifications in the lateral chain of the molecule, but is markedly favored by polar groups in the side of the steroid rings opposite to the side where the methyl groups are located, which stresses the importance of the planar polarity of the molecule. Bile acid–induced increases in BKCa channel activity are also observed in smooth muscle cells freshly dissociated from rabbit main pulmonary artery and gallbladder, raising the possibility that a direct activation of BKCa channels by these planar steroids is a widespread phenomenon in many smooth muscle cell types. Bile acid concentrations that increase BKCa channel activity in mesenteric artery smooth muscle cells are found in the systemic circulation under a variety of human pathophysiological conditions, and their ability to enhance BKCa channel activity may explain their relaxing effect on smooth muscle. PMID:11865021

  9. Conjugated Linoleic Acids and Inflammation: Isomer and Tissue Specific Responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conjugated linoleic acids (CLAs) are a series of geometric and positional isomers of linoleic acid that have been studied for their effects against diabetes, cancer, and atherosclerosis, all conditions with an inflammatory component. Despite the continued interest in CLA, there are many controversi...

  10. 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. PMID:25162837

  11. Self-assembly of aqueous bilirubin ditaurate, a natural conjugated bile pigment, to contraposing enantiomeric dimers and M(-) and P(+) tetramers and their selective hydrophilic disaggregation by monomers and micelles of bile salts.

    PubMed

    Neubrand, Michael W; Carey, Martin C; Laue, Thomas M

    2015-02-24

    The solution behavior of bilirubin ditaurate (BDT), the first naturally occurring conjugated bile pigment to be physically and chemically characterized, was assessed in aqueous solution and in monomeric and micellar solutions of common taurine-conjugated bile salts (BS). Analytical ultracentrifugation revealed that BDT self-associates in monomer-dimer equilibria between 1 and 500 μM, forming limiting tetramers at low millimolar concentrations. Self-association was enthalpically driven with ΔG values of ≈5 kcal/mol, suggesting strong hydrophobic interactions. Added NaCl and decreases in temperature shifted the oligomerization to lower BDT concentrations. On the basis of circular dichroism spectra and the limiting size of the self-aggregates, we infer that the tetramers are composed of 2P(+) and 2M(-) enantiomeric BDT pairs in "ridge-tile" conformations interacting in a "double-bookend" structure. With added monomeric BS, blue shifts in the UV-vis spectra and tight isosbestic points revealed that BDT/BS heterodimers form, followed by BDT "decorating" BS micelles mostly via hydrophilic interactions. Conformational enantiomerism, fluorescence intensities, and anisotropy, as well as resistance of the hybrid particles to disaggregation in 6 M urea, suggested that two or three hydrogen-bonding sites bound BDT monomers to the hydroxyl groups of BS, possibly via pyrrole-π-orbital-OH interactions. BDT stabilized these interactions by enveloping the BS in its "ridge-tile" pincers with variable strain that maximized van der Waals interactions. Possibly because the BDT molecule becomes highly strained with BS subtending a 7β-hydroxyl group, BDT became totally resistant to oxidation in air. This work predicts that, because of BS dissolution of the BDT self-aggregates, BS/bilirubin hybrid particles, which are stabilized hydrophilically, are likely to be the dominant mode of transport for all conjugated bilirubins in bile. PMID:25671490

  12. Ileal mucosal absorption of bile acid in man: validation of a miniature flux chamber technique.

    PubMed Central

    Hosie, K B; Davie, R J; Panagamuwa, B; Grobler, S; Keighley, M R; Birch, N J

    1992-01-01

    A method that allows the quantitative assessment of ileal mucosal cell uptake and transport of bile acids in mucosal biopsy specimens has been validated. Viability of the tissue was confirmed by maintenance of normal cell morphology, wet weight, extracellular space, porosity to polyethylene glycol-900, lactate dehydrogenase release, and transmucosal potential difference. Using 14C-taurocholic acid, absorption was shown to be directional, capable of working against a concentration gradient, reduced by metabolic inhibitors, and sodium dependent. The system showed saturation kinetics with an estimated Km of 10 mumol/l. At a standard substrate concentration of 10 mumol/l ileal mucosal bile acid absorption was compared in patients with colorectal cancer (n = 6), ulcerative colitis (n = 10), and slow transit constipation (n = 8). There was no significant difference in tissue uptake or transport between the three groups. Images Figure 2 PMID:1582593

  13. NMR studies reveal the role of biomembranes in modulating ligand binding and release by intracellular bile acid binding proteins.

    PubMed

    Pedò, Massimo; Löhr, Frank; D'Onofrio, Mariapina; Assfalg, Michael; Dötsch, Volker; Molinari, Henriette

    2009-12-18

    Bile acid molecules are transferred vectorially between basolateral and apical membranes of hepatocytes and enterocytes in the context of the enterohepatic circulation, a process regulating whole body lipid homeostasis. This work addresses the role of the cytosolic lipid binding proteins in the intracellular transfer of bile acids between different membrane compartments. We present nuclear magnetic resonance (NMR) data describing the ternary system composed of the bile acid binding protein, bile acids, and membrane mimetic systems, such as anionic liposomes. This work provides evidence that the investigated liver bile acid binding protein undergoes association with the anionic membrane and binding-induced partial unfolding. The addition of the physiological ligand to the protein-liposome mixture is capable of modulating this interaction, shifting the equilibrium towards the free folded holo protein. An ensemble of NMR titration experiments, based on nitrogen-15 protein and ligand observation, confirm that the membrane and the ligand establish competing binding equilibria, modulating the cytoplasmic permeability of bile acids. These results support a mechanism of ligand binding and release controlled by the onset of a bile salt concentration gradient within the polarized cell. The location of a specific protein region interacting with liposomes is highlighted. PMID:19836400

  14. Validation and application of a liquid-chromatographic/enzymatic assay for individual bile acids in the serum of rats.

    PubMed

    Thompson, M B; Blair, P C; Morris, R W; Neptun, D A; Deyo, D F; Popp, J A

    1987-10-01

    A liquid-chromatographic technique with a post-column enzymatic reaction and fluorescence detection was validated for analysis of individual bile acids in the serum of rats. Extraction recoveries averaged 91.1% (SD 6.9%) for all bile acids. The assay was sensitive (minimum detection of 16.8 pmol per 100-microL injection), linear (r greater than 0.999 for concentrations ranging between 45 and 112,500 pmol per 100-microL injection), and reproducible (mean CVs for three different concentrations of standards and a serum pool ranged from 4.4% to 12.2%). In rats treated for three days with either neomycin, carbon tetrachloride, alpha-naphthylisothiocyanate, or total bile-duct ligation (five animals per group), total concentrations of bile acids were significantly increased (P less than 0.004). Concentrations of 16 of 17 individual bile acids differed significantly between groups (P less than 0.04). Examination of the relative concentrations (percent of total) of individual bile acids by canonical discriminant analysis placed each animal into the appropriate treatment or control group. Use of this technique in toxicological studies can help detect and identify specific types of disruptions in the enterohepatic circulation of bile acids. PMID:3665040

  15. Akt-dependent NF-kappaB activation is required for bile acids to rescue colon cancer cells from stress-induced apoptosis.

    PubMed

    Shant, Jasleen; Cheng, Kunrong; Marasa, Bernard S; Wang, Jian-Ying; Raufman, Jean-Pierre

    2009-02-01

    Conjugated secondary bile acids promote human colon cancer cell proliferation by activating EGF receptors (EGFR). We hypothesized that bile acid-induced EGFR activation also mediates cell survival by downstream Akt-regulated activation of NF-kappaB. Deoxycholyltaurine (DCT) treatment attenuated TNF-alpha-induced colon cancer cell apoptosis, and stimulated rapid and sustained NF-kappaB nuclear translocation and transcriptional activity (detected by NF-kappaB binding to an oligonucleotide consensus sequence and by activation of luciferase reporter gene constructs). Both DCT-induced NF-kappaB nuclear translocation and attenuation of TNF-alpha-stimulated apoptosis were dependent on EGFR activation. Inhibitors of nuclear translocation, proteosome activity, and IkappaBalpha kinase attenuated NF-kappaB transcriptional activity. Cell transfection with adenoviral vectors encoding a non-degradable IkappaBalpha 'super-repressor' blocked the actions of DCT on both NF-kappaB activation and TNF-alpha-induced apoptosis. Likewise, transfection with mutant akt and treatment with a chemical inhibitor of Akt attenuated effects of DCT on NF-kappaB transcriptional activity and TNF-alpha-induced apoptosis. Chemical inhibitors of Akt and NF-kappaB activation also attenuated DCT-induced rescue of H508 cells from ultraviolet radiation-induced apoptosis. Collectively, these observations indicate that, downstream of EGFR, bile acid-induced colon cancer cell survival is mediated by Akt-dependent NF-kappaB activation. These findings provide a mechanism whereby bile acids increase resistance of colon cancer to chemotherapy and radiation. PMID:19056378

  16. Akt-dependent NF-{kappa}B activation is required for bile acids to rescue colon cancer cells from stress-induced apoptosis

    SciTech Connect

    Shant, Jasleen; Cheng, Kunrong; Marasa, Bernard S.; Wang Jianying; Raufman, Jean-Pierre

    2009-02-01

    Conjugated secondary bile acids promote human colon cancer cell proliferation by activating EGF receptors (EGFR). We hypothesized that bile acid-induced EGFR activation also mediates cell survival by downstream Akt-regulated activation of NF-{kappa}B. Deoxycholyltaurine (DCT) treatment attenuated TNF-{alpha}-induced colon cancer cell apoptosis, and stimulated rapid and sustained NF-{kappa}B nuclear translocation and transcriptional activity (detected by NF-{kappa}B binding to an oligonucleotide consensus sequence and by activation of luciferase reporter gene constructs). Both DCT-induced NF-{kappa}B nuclear translocation and attenuation of TNF-{alpha}-stimulated apoptosis were dependent on EGFR activation. Inhibitors of nuclear translocation, proteosome activity, and I{kappa}B{alpha} kinase attenuated NF-{kappa}B transcriptional activity. Cell transfection with adenoviral vectors encoding a non-degradable I{kappa}B{alpha} 'super-repressor' blocked the actions of DCT on both NF-{kappa}B activation and TNF-{alpha}-induced apoptosis. Likewise, transfection with mutant akt and treatment with a chemical inhibitor of Akt attenuated effects of DCT on NF-{kappa}B transcriptional activity and TNF-{alpha}-induced apoptosis. Chemical inhibitors of Akt and NF-{kappa}B activation also attenuated DCT-induced rescue of H508 cells from ultraviolet radiation-induced apoptosis. Collectively, these observations indicate that, downstream of EGFR, bile acid-induced colon cancer cell survival is mediated by Akt-dependent NF-{kappa}B activation. These findings provide a mechanism whereby bile acids increase resistance of colon cancer to chemotherapy and radiation.

  17. Experimental Study of Poly-l-Lactic Acid Biodegradable Stents in Normal Canine Bile Ducts

    SciTech Connect

    Yamamoto, Kiyosei Yoshioka, Tetsuya; Furuichi, Kinya; Sakaguchi, Hiroshi; Anai, Hiroshi; Tanaka, Toshihiro; Morimoto, Kengo; Uchida, Hideo; Kichikawa, Kimihiko

    2011-06-15

    Purpose: This study was designed to clarify the advantages of biodegradable stents in terms of mucosal reaction and biodegradation after placement. We designed a biodegradable stent and assessed stent degradation and changes in the normal bile ducts of dogs. Methods: The biodegradable stent is a balloon-expandable Z stent consisting of poly-l-lactic acid (PLLA) with a diameter of 6 mm and a length of 15 mm. We assessed four groups of three beagle dogs each at 1, 3, 6, and 9 months of follow-up. After evaluating stent migration by radiography and stent and bile duct patency by cholangiography, the dogs were sacrificed to remove the bile duct together with the stent. The bile duct lumen was examined macroscopically and histologically, and the stent degradation was examined macroscopically and by scanning electron microscopy (SEM). Results: Bile duct obstruction was absent and none of the stents migrated. Macroscopic evaluation showed moderate endothelial proliferation in the bile ducts at the implant sites at 3 and 6 months and a slight change at 9 months. Slight mononuclear cell infiltration was histologically identified at all time points and epithelial hyperplasia that was moderate at 3 months was reduced to slight at 6 and 9 months. Stent degradation was macroscopically evident in all animals at 9 months and was proven by SEM in two dogs at 6 months and in all of them at 9 months. Conclusions: Our results suggest that PLLA bioabsorbable stents seems to be useful for implantation in the biliary system with further investigation.

  18. Enzymatic synthesis of bile acid derivatives and biological evaluation against Trypanosoma cruzi.

    PubMed

    García Liñares, Guadalupe; Antonela Zígolo, M; Simonetti, Leandro; Longhi, Silvia A; Baldessari, Alicia

    2015-08-01

    Enzyme catalysis was applied to synthesize derivatives of three bile acids and their biological activity was evaluated as growth inhibitors of the protozoan Trypanosoma cruzi. Twelve mono-, diacetyl and ester derivatives of deoxycholic, chenodeoxycholic and lithocholic acid, seven of them new compounds, were obtained through lipase-catalyzed acetylation, esterification and alcoholysis reactions in very good to excellent yield and a highly regioselective way. Among them, acetylated ester products, in which the lipase catalyzed both reactions in one-pot, were obtained. The influence of various reaction parameters in the enzymatic reactions, such as enzyme source, acylating agent/substrate ratio, enzyme/substrate ratio, solvent and temperature, was studied. Some of the evaluated compounds showed a remarkable activity as Trypanosoma cruzi growth inhibitors, obtaining the best results with ethyl chenodeoxycholate 3-acetate and chenodeoxycholic acid 3,7-diacetate, which showed IC50: 8.6 and 22.8 μM, respectively. In addition, in order to shed light to bile acids behavior in enzymatic reactions, molecular modeling was applied to some derivatives. The advantages showed by the enzymatic methodology, such as mild reaction conditions and low environmental impact, make the biocatalysis a convenient way to synthesize these bile acid derivatives with application as potential antiparasitic agents. PMID:26072173

  19. Determination of bile acids in pharmaceutical formulations using micellar electrokinetic chromatography.

    PubMed

    Rodríguez, V G; Lucangioli, S E; Fernández Otero, G C; Carducci, C N

    2000-08-15

    A micellar electrokinetic chromatography method (MEKC) has been developed and validated for the determination of bile acids (BA) such as ursodeoxycholic acid (UDCA), dehydrocholic acid (DHCA) and deoxycholic acid (DCA) in pharmaceuticals for quality control purpose. The background electrolyte consisted of 20 mM borate-phosphate buffer containing 50 mM sodium dodecylsulfate (SDS), and acetonitrile as additive. UV detection was set at 185 nm. Selectivity, linearity, range, repeatability, intermediate precision and accuracy showed good results. Comparison of the values obtained by MEKC and HPLC methods were in close agreement. PMID:10933529

  20. [The effect of pH and amount of antacids on bile acid binding in a quasi-natural reflux milieu].

    PubMed

    Kurtz, W; Güldütuna, S; Leuschner, U

    1991-05-01

    Bile acid adsorption may be one therapeutical mechanism of antacids. Little is known about the effect of pH and amount of antacid on bile acid adsorption. Therefore we carried out the following investigations using a lattice [correction of lettuce] layer antacid as a model substance. 5 ml of "quasi-natural reflux milieu" were mixed with 0.5, 1 or 2 ml of hydrotalcite and adjusted to pH 3, 5 or 7. The highest total bile acid adsorption was found at pH 3, the degree of bile acid adsorption correlated with bile acid lipophilicity, i.e. the most lipophilic and toxic bile acids are adsorbed best. High adsorption of lipophilic and particularly toxic bile acids even at low gastric pH may help to explain the good therapeutic effect of low-dose antacids in gastric ulcer. PMID:1950032

  1. Activation of Constitutive Androstane Receptor (CAR) in Mice Results in Maintained Biliary Excretion of Bile Acids Despite a Marked Decrease of Bile Acids in Liver.

    PubMed

    Lickteig, Andrew J; Csanaky, Iván L; Pratt-Hyatt, Matthew; Klaassen, Curtis D

    2016-06-01

    Activation of Constitutive Androstane Receptor (CAR) protects against bile acid (BA)-induced liver injury. This study was performed to determine the effect of CAR activation on bile flow, BA profile, as well as expression of BA synthesis and transport genes. Synthetic CAR ligand 1,4-bis-[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) was administered to mice for 4 days. BAs were quantified by UPLC-MS/MS (ultraperformance liquid chromatography-tandem mass spectrometry). CAR activation decreases total BAs in livers of male (49%) and female mice (26%), largely attributable to decreases of the 12α-hydroxylated BA taurocholic acid (T-CA) (males (M) 65%, females (F) 45%). Bile flow in both sexes was increased by CAR activation, and the increases were BA-independent. CAR activation did not alter biliary excretion of total BAs, but overall BA composition changed. Excretion of muricholic (6-hydroxylated) BAs was increased in males (101%), and the 12α-OH proportion of biliary BAs was decreased in both males (37%) and females (28%). The decrease of T-CA in livers of males and females correlates with the decreased mRNA of the sterol 12α-hydroxylase Cyp8b1 in males (71%) and females (54%). As a response to restore BAs to physiologic concentrations in liver, mRNA of Cyp7a1 is upregulated following TCPOBOP (males 185%, females 132%). In ilea, mRNA of the negative feedback regulator Fgf15 was unaltered by CAR activation, indicating biliary BA excretion was sufficient to maintain concentrations of total BAs in the small intestine. In summary, the effects of CAR activation on BAs in male and female mice are quite similar, with a marked decrease in the major BA T-CA in the liver. PMID:26984780

  2. Bile acids influence the growth, oestrogen receptor and oestrogen-regulated proteins of MCF-7 human breast cancer cells.

    PubMed Central

    Baker, P. R.; Wilton, J. C.; Jones, C. E.; Stenzel, D. J.; Watson, N.; Smith, G. J.

    1992-01-01

    The effects of the major human serum bile acid, glycochenodeoxycholic acid (GCDC), as well as unconjugated chenodeoxycholic acid (CDC), on the MCF-7 human breast cancer cell line have been studied in vitro under oestro