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Zhang B, Jiang X, Yu Y, Cui Y, Wang W, Luo H, Stergiadis S, Wang B. Rumen microbiome-driven insight into bile acid metabolism and host metabolic regulation. THE ISME JOURNAL 2024; 18:wrae098. [PMID: 38836500 PMCID: PMC11193847 DOI: 10.1093/ismejo/wrae098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/20/2024] [Accepted: 06/04/2024] [Indexed: 06/06/2024]
Abstract
Gut microbes play a crucial role in transforming primary bile acids (BAs) into secondary forms, which influence systemic metabolic processes. The rumen, a distinctive and critical microbial habitat in ruminants, boasts a diverse array of microbial species with multifaceted metabolic capabilities. There remains a gap in our understanding of BA metabolism within this ecosystem. Herein, through the analysis of 9371 metagenome-assembled genomes and 329 cultured organisms from the rumen, we identified two enzymes integral to BA metabolism: 3-dehydro-bile acid delta4,6-reductase (baiN) and the bile acid:Na + symporter family (BASS). Both in vitro and in vivo experiments were employed by introducing exogenous BAs. We revealed a transformation of BAs in rumen and found an enzyme cluster, including L-ribulose-5-phosphate 3-epimerase and dihydroorotate dehydrogenase. This cluster, distinct from the previously known BA-inducible operon responsible for 7α-dehydroxylation, suggests a previously unrecognized pathway potentially converting primary BAs into secondary BAs. Moreover, our in vivo experiments indicated that microbial BA administration in the rumen can modulate amino acid and lipid metabolism, with systemic impacts underscored by core secondary BAs and their metabolites. Our study provides insights into the rumen microbiome's role in BA metabolism, revealing a complex microbial pathway for BA biotransformation and its subsequent effect on host metabolic pathways, including those for glucose, amino acids, and lipids. This research not only advances our understanding of microbial BA metabolism but also underscores its wider implications for metabolic regulation, offering opportunities for improving animal and potentially human health.
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Affiliation(s)
- Boyan Zhang
- State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, P. R. China
| | - Xianzhe Jiang
- State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, P. R. China
| | - Yue Yu
- State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, P. R. China
| | - Yimeng Cui
- State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, P. R. China
| | - Wei Wang
- State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, P. R. China
| | - Hailing Luo
- State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, P. R. China
| | - Sokratis Stergiadis
- Department of Animal Sciences, School of Agriculture Policy and Development, University of Reading, Reading RG6 6EU, United Kingdom
| | - Bing Wang
- State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, P. R. China
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Louca P, Meijnikman AS, Nogal A, Asnicar F, Attaye I, Vijay A, Kouraki A, Visconti A, Wong K, Berry SE, Leeming ER, Mompeo O, Tettamanzi F, Baleanu AF, Falchi M, Hadjigeorgiou G, Wolf J, Acherman YIZ, Van de Laar AW, Gerdes VEA, Michelotti GA, Franks PW, Segata N, Mangino M, Spector TD, Bulsiewicz WJ, Nieuwdorp M, Valdes AM, Menni C. The secondary bile acid isoursodeoxycholate correlates with post-prandial lipemia, inflammation, and appetite and changes post-bariatric surgery. Cell Rep Med 2023; 4:100993. [PMID: 37023745 PMCID: PMC10140478 DOI: 10.1016/j.xcrm.2023.100993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/12/2022] [Accepted: 03/14/2023] [Indexed: 04/08/2023]
Abstract
Primary and secondary bile acids (BAs) influence metabolism and inflammation, and the gut microbiome modulates levels of BAs. We systematically explore the host genetic, gut microbial, and habitual dietary contribution to a panel of 19 serum and 15 stool BAs in two population-based cohorts (TwinsUK, n = 2,382; ZOE PREDICT-1, n = 327) and assess changes post-bariatric surgery and after nutritional interventions. We report that BAs have a moderately heritable genetic component, and the gut microbiome accurately predicts their levels in serum and stool. The secondary BA isoursodeoxycholate (isoUDCA) can be explained mostly by gut microbes (area under the receiver operating characteristic curve [AUC] = ∼80%) and associates with post-prandial lipemia and inflammation (GlycA). Furthermore, circulating isoUDCA decreases significantly 1 year after bariatric surgery (β = -0.72, p = 1 × 10-5) and in response to fiber supplementation (β = -0.37, p < 0.03) but not omega-3 supplementation. In healthy individuals, isoUDCA fasting levels correlate with pre-meal appetite (p < 1 × 10-4). Our findings indicate an important role for isoUDCA in lipid metabolism, appetite, and, potentially, cardiometabolic risk.
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Affiliation(s)
- Panayiotis Louca
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK
| | - Abraham S Meijnikman
- Department of (Experimental) Vascular Medicine, Amsterdam University Medical Centre (UMC), Amsterdam, the Netherlands
| | - Ana Nogal
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK
| | | | - Ilias Attaye
- Department of (Experimental) Vascular Medicine, Amsterdam University Medical Centre (UMC), Amsterdam, the Netherlands
| | - Amrita Vijay
- Nottingham NIHR Biomedical Research Centre at the School of Medicine, University of Nottingham, NG5 1PB Nottingham, UK; Inflammation, Recovery and Injury Sciences, School of Medicine, University of Nottingham, NG5 1PB Nottingham, UK
| | - Afroditi Kouraki
- Nottingham NIHR Biomedical Research Centre at the School of Medicine, University of Nottingham, NG5 1PB Nottingham, UK; Inflammation, Recovery and Injury Sciences, School of Medicine, University of Nottingham, NG5 1PB Nottingham, UK
| | - Alessia Visconti
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK
| | - Kari Wong
- Metabolon, Research Triangle Park, Morrisville, NC, USA
| | - Sarah E Berry
- Department of Nutritional Sciences, King's College London, London, UK
| | - Emily R Leeming
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK
| | - Olatz Mompeo
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK
| | - Francesca Tettamanzi
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK
| | - Andrei-Florin Baleanu
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK
| | - Mario Falchi
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK
| | | | | | | | | | - Victor E A Gerdes
- Department of (Experimental) Vascular Medicine, Amsterdam University Medical Centre (UMC), Amsterdam, the Netherlands
| | | | - Paul W Franks
- Lund University Diabetes Center, Lund University, Malmö, Sweden; Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Nicola Segata
- Department CIBIO, University of Trento, Trento, Italy
| | - Massimo Mangino
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK; NIHR Biomedical Research Centre at Guy's and St Thomas' Foundation Trust, SE1 9RT London, UK
| | - Tim D Spector
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK
| | | | - Max Nieuwdorp
- Department of (Experimental) Vascular Medicine, Amsterdam University Medical Centre (UMC), Amsterdam, the Netherlands
| | - Ana M Valdes
- Nottingham NIHR Biomedical Research Centre at the School of Medicine, University of Nottingham, NG5 1PB Nottingham, UK; Inflammation, Recovery and Injury Sciences, School of Medicine, University of Nottingham, NG5 1PB Nottingham, UK.
| | - Cristina Menni
- Department of Twin Research & Genetic Epidemiology, King's College London, SE1 7EH London, UK.
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Lucas LN, Barrett K, Kerby RL, Zhang Q, Cattaneo LE, Stevenson D, Rey FE, Amador-Noguez D. Dominant Bacterial Phyla from the Human Gut Show Widespread Ability To Transform and Conjugate Bile Acids. mSystems 2021; 6:e0080521. [PMID: 34463573 DOI: 10.1128/msystems.00805-21] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022] Open
Abstract
Gut bacteria influence human physiology by chemically modifying host-synthesized primary bile acids. These modified bile acids, known as secondary bile acids, can act as signaling molecules that modulate host lipid, glucose, and energy metabolism and affect gut microbiota composition via selective antimicrobial properties. However, knowledge regarding the bile acid-transforming capabilities of individual gut microbes remains limited. To help address this knowledge gap, we screened 72 bacterial isolates, spanning seven major phyla commonly found in the human gut, for their ability to chemically modify unconjugated bile acids. We found that 43 isolates, representing 41 species, were capable of in vitro modification of one or more of the three most abundant unconjugated bile acids in humans: cholic acid, chenodeoxycholic acid, and deoxycholic acid. Of these, 32 species have not been previously described as bile acid transformers. The most prevalent bile acid transformations detected were oxidation of 3α-, 7α-, or 12α-hydroxyl groups on the steroid core, a reaction catalyzed by hydroxysteroid dehydrogenases. In addition, we found 7α-dehydroxylation activity to be distributed across various bacterial genera, and we observed several other complex bile acid transformations. Finally, our screen revealed widespread bacterial conjugation of primary and secondary bile acids to glycine, a process that was thought to only occur in the liver, and to 15 other amino acids, resulting in the discovery of 44 novel microbially conjugated bile acids. IMPORTANCE Our current knowledge regarding microbial bile acid transformations comes primarily from biochemical studies on a relatively small number of species or from bioinformatic predictions that rely on homology to known bile acid-transforming enzyme sequences. Therefore, much remains to be learned regarding the variety of bile acid transformations and their representation across gut microbial species. By carrying out a systematic investigation of bacterial species commonly found in the human intestinal tract, this study helps better define the gut bacteria that impact composition of the bile acid pool, which has implications in the context of metabolic disorders and cancers of the digestive tract. Our results greatly expand upon the list of bacterial species known to perform different types of bile acid transformations. This knowledge will be vital for assessing the causal connections between the microbiome, bile acid pool composition, and human health.
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Affiliation(s)
- L N Lucas
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - K Barrett
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - R L Kerby
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Q Zhang
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - L E Cattaneo
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - D Stevenson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - F E Rey
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - D Amador-Noguez
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Secondary (iso)BAs cooperate with endogenous ligands to activate FXR under physiological and pathological conditions. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166153. [PMID: 33895309 PMCID: PMC8177068 DOI: 10.1016/j.bbadis.2021.166153] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/24/2021] [Accepted: 04/19/2021] [Indexed: 12/30/2022]
Abstract
IsoBAs, stereoisomers of primary and secondary BAs, are found in feces and plasma of human individuals. BA signaling via the nuclear receptor FXR is crucial for regulation of hepatic and intestinal physiology/pathophysiology. AIM Investigate the ability of BA-stereoisomers to bind and modulate FXR under physiological/pathological conditions. METHODS Expression-profiling, luciferase-assays, fluorescence-based coactivator-association assays, administration of (iso)-BAs to WT and cholestatic mice. RESULTS Compared to CDCA/isoCDCA, administration of DCA/isoDCA, UDCA/isoUDCA only slightly increased mRNA expression of FXR target genes; the induction was more evident looking at pre-mRNAs. Notably, almost 50% of isoBAs were metabolized to 3-oxo-BAs within 4 h in cell-based assays, making it difficult to study their actions. FRET-based real-time monitoring of FXR activity revealed that isoCDCA>CDCA stimulated FXR, and isoDCA and isoUDCA allowed fully activated FXR to be re-stimulated by a second dose of GW4064. In vivo co-administration of a single dose of isoBAs followed by GW4064 cooperatively activated FXR, as did feeding of UDCA in a background of endogenous FXR ligands. However, in animals with biliary obstruction and concomitant loss of intestinal BAs, UDCA was unable to increase intestinal Fgf15. In contrast, mice with an impaired enterohepatic circulation of BAs (Asbt-/-, Ostα-/-), administration of UDCA was still able to induce ileal Fgf15 and repress hepatic BA-synthesis, arguing that UDCA is only effective in the presence of endogenous FXR ligands. CONCLUSION Secondary (iso)BAs cooperatively activate FXR in the presence of endogenous BAs, which is important to consider in diseases linked to disturbances in BA enterohepatic cycling.
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5
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Dosedělová V, Itterheimová P, Kubáň P. Analysis of bile acids in human biological samples by microcolumn separation techniques: A review. Electrophoresis 2020; 42:68-85. [PMID: 32645223 DOI: 10.1002/elps.202000139] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/03/2020] [Accepted: 07/04/2020] [Indexed: 12/13/2022]
Abstract
Bile acids are a group of compounds essential for lipid digestion and absorption with a steroid skeleton and a carboxylate side chain usually conjugated to glycine or taurine. Bile acids are regulatory molecules for a number of metabolic processes and can be used as biomarkers of various disorders. Since the middle of the twentieth century, the detection of bile acids has evolved from simple qualitative analysis to accurate quantification in complicated mixtures. Advanced methods are required to characterize and quantify individual bile acids in these mixtures. This article overviews the literature from the last two decades (2000-2020) and focuses on bile acid analysis in various human biological samples. The methods for sample preparation, including the sample treatment of conventional (blood plasma, blood serum, and urine) and unconventional samples (bile, saliva, duodenal/gastric juice, feces, etc.) are shortly discussed. Eventually, the focus is on novel analytical approaches and methods for each particular biological sample, providing an overview of the microcolumn separation techniques, such as high-performance liquid chromatography, gas chromatography, and capillary electrophoresis, used in their analysis. This is followed by a discussion on selected clinical applications.
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Affiliation(s)
- Věra Dosedělová
- Department of Bioanalytical Instrumentation, CEITEC Masaryk University, Brno, Czech Republic
| | - Petra Itterheimová
- Department of Bioanalytical Instrumentation, CEITEC Masaryk University, Brno, Czech Republic
| | - Petr Kubáň
- Department of Bioanalytical Instrumentation, Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Brno, Czech Republic
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6
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Dawson PA, Karpen SJ. Intestinal transport and metabolism of bile acids. J Lipid Res 2014; 56:1085-99. [PMID: 25210150 DOI: 10.1194/jlr.r054114] [Citation(s) in RCA: 351] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Indexed: 12/17/2022] Open
Abstract
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.
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Affiliation(s)
- Paul A Dawson
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, GA 30322
| | - Saul J Karpen
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, GA 30322
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7
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Hofmann AF, Hagey LR. Key discoveries in bile acid chemistry and biology and their clinical applications: history of the last eight decades. J Lipid Res 2014; 55:1553-95. [PMID: 24838141 DOI: 10.1194/jlr.r049437] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Indexed: 12/12/2022] Open
Abstract
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.
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Affiliation(s)
- Alan F Hofmann
- Department of Medicine, University of California, San Diego, San Diego, CA
| | - Lee R Hagey
- Department of Medicine, University of California, San Diego, San Diego, CA
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8
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González PM, Lagos CF, Ward WC, Polli JE. 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. Mol Pharm 2013; 11:588-98. [PMID: 24328955 DOI: 10.1021/mp400575t] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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 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 toward-plane. Our results emphasize the relevance of the 3α-OH group on BAs for proper hASBT binding and transport and revealed the critical role of 7-OH group on BA translocation, particularly in the absence of a 3α-OH group. Results have implications for BA prodrug design.
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Affiliation(s)
- Pablo M González
- Departamento de Farmacia, Facultad de Química, Pontificia Universidad Católica de Chile , Av Vicuña Mackenna 4860, Santiago, Chile
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9
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Tsai SJJ, Zhong YS, Weng JF, Huang HH, Hsieh PY. Determination of bile acids in pig liver, pig kidney and bovine liver by gas chromatography-chemical ionization tandem mass spectrometry with total ion chromatograms and extraction ion chromatograms. J Chromatogr A 2011; 1218:524-33. [DOI: 10.1016/j.chroma.2010.11.062] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 11/19/2010] [Accepted: 11/25/2010] [Indexed: 12/11/2022]
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10
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Abu-Hayyeh S, Martinez-Becerra P, Sheikh Abdul Kadir SH, Selden C, Romero MR, Rees M, Marschall HU, Marin JJG, Williamson C. Inhibition of Na+-taurocholate Co-transporting polypeptide-mediated bile acid transport by cholestatic sulfated progesterone metabolites. J Biol Chem 2010; 285:16504-12. [PMID: 20177056 DOI: 10.1074/jbc.m109.072140] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Sulfated progesterone metabolite (P4-S) levels are raised in normal pregnancy and elevated further in intrahepatic cholestasis of pregnancy (ICP), a bile acid-liver disorder of pregnancy. ICP can be complicated by preterm labor and intrauterine death. The impact of P4-S on bile acid uptake was studied using two experimental models of hepatic uptake of bile acids, namely cultured primary human hepatocytes (PHH) and Na(+)-taurocholate co-transporting polypeptide (NTCP)-expressing Xenopus laevis oocytes. Two P4-S compounds, allopregnanolone-sulfate (PM4-S) and epiallopregnanolone-sulfate (PM5-S), reduced [(3)H]taurocholate (TC) uptake in a dose-dependent manner in PHH, with both Na(+)-dependent and -independent bile acid uptake systems significantly inhibited. PM5-S-mediated inhibition of TC uptake could be reversed by increasing the TC concentration against a fixed PM5-S dose indicating competitive inhibition. Experiments using NTCP-expressing Xenopus oocytes confirmed that PM4-S/PM5-S are capable of competitively inhibiting NTCP-mediated uptake of [(3)H]TC. Total serum PM4-S + PM5-S levels were measured in non-pregnant and third trimester pregnant women using liquid chromatography-electrospray tandem mass spectrometry and were increased in pregnant women, at levels capable of inhibiting TC uptake. In conclusion, pregnancy levels of P4-S can inhibit Na(+)-dependent and -independent influx of taurocholate in PHH and cause competitive inhibition of NTCP-mediated uptake of taurocholate in Xenopus oocytes.
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Affiliation(s)
- Shadi Abu-Hayyeh
- Institute for Reproductive and Developmental Biology, Imperial College London, London W12 0NN, United Kingdom
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11
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Hofmann AF, Hagey LR, Krasowski MD. Bile salts of vertebrates: structural variation and possible evolutionary significance. J Lipid Res 2009; 51:226-46. [PMID: 19638645 DOI: 10.1194/jlr.r000042] [Citation(s) in RCA: 264] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Biliary bile salt composition of 677 vertebrate species (103 fish, 130 reptiles, 271 birds, 173 mammals) was determined. Bile salts were of three types: C(27) bile alcohols, C(27) bile acids, or C(24) bile acids, with default hydroxylation at C-3 and C-7. C(27) bile alcohols dominated in early evolving fish and amphibians; C(27) bile acids, in reptiles and early evolving birds. C(24) bile acids were present in all vertebrate classes, often with C(27) alcohols or with C(27) acids, indicating two evolutionary pathways from C(27) bile alcohols to C(24) bile acids: a) a 'direct' pathway and b) an 'indirect' pathway with C(27) bile acids as intermediates. Hydroxylation at C-12 occurred in all orders and at C-16 in snakes and birds. Minor hydroxylation sites were C-1, C-2, C-5, C-6, and C-15. Side chain hydroxylation in C(27) bile salts occurred at C-22, C-24, C-25, and C-26, and in C(24) bile acids, at C-23 (snakes, birds, and pinnipeds). Unexpected was the presence of C(27) bile alcohols in four early evolving mammals. Bile salt composition showed significant variation between orders but not between families, genera, or species. Bile salt composition is a biochemical trait providing clues to evolutionary relationships, complementing anatomical and genetic analyses.
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Affiliation(s)
- Alan F Hofmann
- Department of Medicine, University of California, San Diego, San Diego, CA 92093-0063, USA.
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12
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Gas chromatography–mass spectrometry of the trimethylsilyl (oxime) ether/ester derivatives of cholic acids: Their presence in the aquatic environment. J Chromatogr A 2008; 1211:104-12. [DOI: 10.1016/j.chroma.2008.09.079] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 09/16/2008] [Accepted: 09/19/2008] [Indexed: 11/18/2022]
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13
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Glantz A, Reilly SJ, Benthin L, Lammert F, Mattsson LA, Marschall HU. Intrahepatic cholestasis of pregnancy: Amelioration of pruritus by UDCA is associated with decreased progesterone disulphates in urine. Hepatology 2008; 47:544-51. [PMID: 17968976 DOI: 10.1002/hep.21987] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
UNLABELLED Intrahepatic cholestasis of pregnancy (ICP) is characterized by pruritus, elevated bile acids, and, specifically, elevated disulphated progesterone metabolites. We aimed to study changes in these parameters during treatment with dexamethasone or ursodeoxycholic acid (UDCA) in 40 out of 130 women included in the Swedish ICP intervention trial (26 randomized to placebo or UDCA, 14 randomized to dexamethasone). Serum bile acid profiles and urinary steroid hormone metabolites were analyzed using isotope-dilution gas chromatography-mass spectrometry and electrospray-mass spectrometry. We found that all patients displayed ICP-typical serum bile acid profiles with >50% cholic acid at baseline but almost 80% UDCA upon treatment with this bile acid. In UDCA-treated patients, relative amounts of disulphated progesterone metabolites in urine decreased by 34%, 48% (P < 0.05), and 55% (P < 0.05) after 1, 2, and 3 weeks of treatment, respectively, which was significantly correlated to improvements of pruritus scores but not to serum bile acid levels. In contrast, in patients randomized to dexamethasone or placebo, no changes in steroid metabolites or pruritus scores were observed. CONCLUSION UDCA treatment in ICP decreased urinary excretion of disulphated progesterone metabolites, suggesting that amelioration of pruritus is connected to stimulation of hepatobiliary excretion of progesterone disulphates.
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Affiliation(s)
- Anna Glantz
- Department of Obstetrics and Gynaecology, Sahlgrenska University Hospital/East, Gothenburg, Sweden
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Fickert P, Wagner M, Marschall HU, Fuchsbichler A, Zollner G, Tsybrovskyy O, Zatloukal K, Liu J, Waalkes MP, Cover C, Denk H, Hofmann AF, Jaeschke H, Trauner M. 24-norUrsodeoxycholic acid is superior to ursodeoxycholic acid in the treatment of sclerosing cholangitis in Mdr2 (Abcb4) knockout mice. Gastroenterology 2006; 130:465-81. [PMID: 16472600 DOI: 10.1053/j.gastro.2005.10.018] [Citation(s) in RCA: 218] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Accepted: 10/12/2005] [Indexed: 01/03/2023]
Abstract
BACKGROUND & AIMS Current therapy for primary sclerosing cholangitis is of limited efficacy. Multidrug resistance gene 2 knockout mice (Mdr2(-/-)) represent a well-characterized model for sclerosing cholangitis. Experiments were performed to test in such mice the therapeutic effects of 24-norUrsodeoxycholic acid, a C(23) homologue of ursodeoxycholic acid with 1 fewer methylene group in its side chain. METHODS Mdr2(-/-) mice were fed a diet containing 24-norUrsodeoxycholic acid (0.5% wt/wt) or ursodeoxycholic acid (0.5% wt/wt) as a clinical comparator for 4 weeks; controls received standard chow. Effects on serum liver tests, liver histology, markers of inflammation and fibrosis, and bile acid transport and metabolism were compared. 24-norUrsodeoxycholic acid metabolism was studied in serum, liver, bile, and urine. RESULTS 24-norUrsodeoxycholic acid markedly improved liver tests and liver histology and significantly reduced hydroxyproline content and the number of infiltrating neutrophils and proliferating hepatocytes and cholangiocytes. 24-norUrsodeoxycholic acid underwent extensive phase I/II metabolism (hydroxylation, sulfation, and glucuronidation), thereby increasing the hydrophilicity of biliary bile acid secretion. There was a coordinated induction of bile acid detoxifying enzymes (Cyp2b10, Cyp3a11, and Sult2a1) and efflux pumps (Mrp3 and Mrp4). Ursodeoxycholic acid, in contrast, increased alanine transaminase and alkaline phosphatase levels, had no significant effects on hydroxyproline content, and induced biliary transporters and detoxification enzymes to a much smaller extent than 24-norUrsodeoxycholic acid. CONCLUSIONS 24-norUrsodeoxycholic acid ameliorates sclerosing cholangitis in Mdr2(-/-) mice. Its therapeutic mechanisms involve (1) increasing the hydrophilicity of biliary bile acids, (2) stimulating bile flow with flushing of injured bile ducts, and (3) inducing detoxification and elimination routes for bile acids.
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Affiliation(s)
- Peter Fickert
- Department of Medicine, Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Medical University Graz, Austria
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15
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Warskulat U, Borsch E, Reinehr R, Heller-Stilb B, Mönnighoff I, Buchczyk D, Donner M, Flögel U, Kappert G, Soboll S, Beer S, Pfeffer K, Marschall HU, Gabrielsen M, Amiry-Moghaddam M, Ottersen OP, Dienes HP, Häussinger D. Chronic liver disease is triggered by taurine transporter knockout in the mouse. FASEB J 2006; 20:574-6. [PMID: 16421246 DOI: 10.1096/fj.05-5016fje] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Taurine is an abundant organic osmolyte with antioxidant and immunomodulatory properties. Its role in the pathogenesis of chronic liver disease is unknown. The liver phenotype was studied in taurine transporter knockout (taut-/-) mice. Hepatic taurine levels were ~21, 15 and 6 mumol/g liver wet weight in adult wild-type, heterozygous (taut+/-) and homozygous (taut-/-) mice, respectively. Immunoelectronmicroscopy revealed an almost complete depletion of taurine in Kupffer and sinusoidal endothelial cells, but not in parenchymal cells of (taut-/-) mice. Compared with wild-type mice, (taut-/-) and (taut+/-) mice developed moderate unspecific hepatitis and liver fibrosis with increased frequency of neoplastic lesions beyond 1 year of age. Liver disease in (taut-/-) mice was characterized by hepatocyte apoptosis, activation of the CD95 system, elevated plasma TNF-alpha levels, hepatic stellate cell and oval cell proliferation, and severe mitochondrial abnormalities in liver parenchymal cells. Mitochondrial dysfunction was suggested by a significantly lower respiratory control ratio in isolated mitochondria from (taut-/-) mice. Taut knockout had no effect on taurine-conjugated bile acids in bile; however, the relative amount of cholate-conjugates acid was decreased at the expense of 7-keto-cholate-conjugates. In conclusion, taurine deficiency due to defective taurine transport triggers chronic liver disease, which may involve mitochondrial dysfunction.
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Affiliation(s)
- Ulrich Warskulat
- Clinic for Gastroenterology, Hepatology, and Infectiology, Heinrich Heine University, Düsseldorf, Germany
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16
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Marschall HU, Wagner M, Bodin K, Zollner G, Fickert P, Gumhold J, Silbert D, Fuchsbichler A, Sjövall J, Trauner M. Fxr(-/-) mice adapt to biliary obstruction by enhanced phase I detoxification and renal elimination of bile acids. J Lipid Res 2005; 47:582-92. [PMID: 16327028 DOI: 10.1194/jlr.m500427-jlr200] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Farnesoid X receptor knockout (Fxr(-/-)) mice cannot upregulate the bile salt export pump in bile acid loading or cholestatic conditions. To investigate whether Fxr(-/-) mice differ in bile acid detoxification compared with wild-type mice, we performed a comprehensive analysis of bile acids extracted from liver, bile, serum, and urine of naive and common bile duct-ligated wild-type and Fxr(-/-) mice using electrospray and gas chromatography mass spectrometry. In addition, hepatic and renal gene expression levels of Cyp2b10 and Cyp3a11, and protein expression levels of putative renal bile acid-transporting proteins, were investigated. We found significantly enhanced hepatic bile acid hydroxylation in Fxr(-/-) mice, in particular hydroxylations of cholic acid in the 1beta, 2beta, 4beta, 6alpha, 6beta, 22, or 23 position and a significantly enhanced excretion of these metabolites in urine. The gene expression level of Cyp3a11 was increased in the liver of Fxr(-/-) mice, whereas the protein expression levels of multidrug resistance-related protein 4 (Mrp4) were increased in kidneys of both genotypes during common bile duct ligation. In conclusion, Fxr(-/-) mice detoxify accumulating bile acids in the liver by enhanced hydroxylation reactions probably catalyzed by Cyp3a11. The metabolites formed were excreted into urine, most likely with the participation of Mrp4.
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Affiliation(s)
- Hanns-Ulrich Marschall
- Karolinska Institutet, Department of Medicine at Karolinska University Hospital Huddinge, S-14186 Stockholm, Sweden.
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17
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Wagner M, Halilbasic E, Marschall HU, Zollner G, Fickert P, Langner C, Zatloukal K, Denk H, Trauner M. CAR and PXR agonists stimulate hepatic bile acid and bilirubin detoxification and elimination pathways in mice. Hepatology 2005; 42:420-30. [PMID: 15986414 DOI: 10.1002/hep.20784] [Citation(s) in RCA: 236] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
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.
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Affiliation(s)
- Martin Wagner
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Medicine, Medical University Graz, Auenbruggerplatz 15, A-8036 Graz, Austria
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18
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Fickert P, Trauner M, Fuchsbichler A, Zollner G, Wagner M, Marschall HU, Zatloukal K, Denk H. Oncosis represents the main type of cell death in mouse models of cholestasis. J Hepatol 2005; 42:378-85. [PMID: 15710221 DOI: 10.1016/j.jhep.2004.10.016] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2004] [Revised: 10/14/2004] [Accepted: 10/15/2004] [Indexed: 01/08/2023]
Abstract
BACKGROUND/AIMS Since the mechanisms leading to hepatocyte death in cholestasis are not well defined, we aimed to obtain closer insights into the related pathogenetic principles. METHODS Cell death was assessed in common bile duct ligated (CBDL) and cholic acid (CA)-fed mice, and compared to Fas agonist Jo2-injected mice by studying H and E-stained tissue sections, DNA ladder analysis, caspase-3-like activity assay, immunohistochemistry, double immunofluorescence microscopy for activated caspase-3 and cytokeratin (CK) 18, the TUNEL method, and electron microscopy. RESULTS Jo2-treated mice showed activation of caspase-3, breakdown of the CK intermediate filament network, and classical morphological features of apoptosis. In contrast, in CA-fed and CBDL mice, oncosis characterized by cell swelling and ruptured cell membranes was the predominant type of cell death, whereas in both experimental conditions significant activation of caspase-3 was absent and typical CK alterations were rare despite frequent positivity of the TUNEL assay. CONCLUSIONS (i) Oncosis represents the main type of hepatocyte death in acute cholestasis in mice. (ii) The importance of apoptosis in cholestasis may be overestimated if non-specific detection systems (e.g. TUNEL assay) are used.
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Affiliation(s)
- Peter Fickert
- Laboratory of Experimental Hepatology, Division of Gastroenterology and Hepatology, Department of Medicine, Medical University, Auenbruggerplatz 15, A-8036 Graz, Austria.
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19
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Baisini O, Benini F, Petraglia F, Kuhnz W, Scalia S, Marschall HU, Brunetti G, Tauschel HD, Lanzini A. Ursodeoxycholic acid does not affect ethinylestradiol bioavailability in women taking oral contraceptives. Eur J Clin Pharmacol 2004; 60:481-7. [PMID: 15289960 DOI: 10.1007/s00228-004-0796-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Contraception is recommended for female patients during ursodeoxycholic acid (UDCA) treatment for the potential teratogenic effect of this bile acid, and the aim of our study was to determine whether this treatment affects the bioavailability of ethinylestradiol (EE2). METHODS In this double-blind, randomised study, we measured EE2 pharmacokinetics in eight healthy volunteers randomly allocated to receive oral contraceptive (30 microg EE2 and 75 microg gestodene) plus either UDCA (8-10 mg/kg per day) or placebo for 21 days during the first of three consecutive menstrual cycles. After a washout period during the second cycle, the subjects received the alternative treatment during the third menstrual cycle. Serum EE2 and UDCA were measured using radioimmunoassay and gas chromatography-mass spectrometry, respectively. RESULTS The profile for serum EE2 concentration was similar during UDCA (mean maximum serum concentration 177 pg/ml, SEM 59) and during placebo treatment (153 pg/ml, SEM 62), and mean area under the curve (AUC) was 1374 pg/h per ml (SEM 580) and 1320 pg/h per ml (SEM 551) during the two regimens, respectively. The point estimates and 90% confidence intervals of UDCA/placebo ratios for EE2 AUC and for maximum serum concentration were 1.1 (0.8-1.5) and 1.2 (1.0-1.4), respectively. Mean serum triglycerides concentration increased from 58.3 mg/dl (SEM 6.8) at enrolment to 91.4 mg/dl (SEM 10.7) during placebo (P < 0.01) and to 88.6 mg/dl (SEM 13.7) during UDCA treatment (P < 0.05). During UDCA treatment, serum enrichment with this bile acid and with the metabolite iso-UDCA was 29% (16%) and 3% (2%), respectively. CONCLUSION Co-administration with UDCA does not affect the bioavailability of EE2 in healthy volunteers, indicating that contraceptive efficacy is not affected.
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Affiliation(s)
- Ornella Baisini
- Gastroenterology Unit, Medicine 1, University and Spedali Civili of Brescia, 25125 Brescia, Italy
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20
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Fickert P, Fuchsbichler A, Wagner M, Zollner G, Kaser A, Tilg H, Krause R, Lammert F, Langner C, Zatloukal K, Marschall HU, Denk H, Trauner M. Regurgitation of bile acids from leaky bile ducts causes sclerosing cholangitis in Mdr2 (Abcb4) knockout mice. Gastroenterology 2004; 127:261-74. [PMID: 15236191 DOI: 10.1053/j.gastro.2004.04.009] [Citation(s) in RCA: 338] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Because the mechanisms leading to bile duct damage in sclerosing cholangitis are unknown, we aimed to determine the pathogenesis of bile duct injury in multidrug resistance gene (Mdr2) (Abcb4) knockout mice (Mdr2(-/-)) as a novel model of the disease. METHODS Mdr2(-/-) and wild-type controls (Mdr2(+/+)) were studied at 2, 4, and 8 weeks of age. Liver histology, ultrastructure, immunofluorescence microscopy (to study inflammatory cells, tight junction protein ZO-1, basement membrane protein laminin, fluorescence-labeled ursodeoxycholic acid), immunohistochemistry (for alpha-smooth muscle actin, nitrotyrosine), sirius red staining, bacterial cultures of intra-abdominal organs, and polymerase chain reaction (PCR) for Helicobacter bilis DNA were compared between both genotypes. Hepatic cytokine expression was determined by reverse-transcription PCR. RESULTS Bile ducts of Mdr2(-/-) showed disrupted tight junctions and basement membranes, bile acid leakage into portal tracts, induction of a portal inflammatory (CD11b, CD4-positive) infiltrate, and activation of proinflammatory (tumor necrosis factor [TNF]-alpha, interleukin [IL]-1beta) and profibrogenic cytokines (transforming growth factor [TGF]-beta1). This resulted in activation of periductal myofibroblasts, leading to periductal fibrosis, separating the peribiliary plexus from bile duct epithelial cells and, finally, causing atrophy and death of the bile duct epithelium. Bacterial translocation was not increased and H. bilis was not detectable in Mdr2(-/-). CONCLUSIONS Sclerosing cholangitis in Mdr2(-/-) mice is a multistep process with regurgitation of bile from leaky ducts into the portal tracts, leading to induction of periductal inflammation, followed by activation of periductal fibrogenesis, finally causing obliterative cholangitis owing to atrophy and death of bile duct epithelial cells.
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Affiliation(s)
- Peter Fickert
- Deparment of Medicine, Medical University, Graz, Austria
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21
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Zollner G, Fickert P, Fuchsbichler A, Silbert D, Wagner M, Arbeiter S, Gonzalez FJ, Marschall HU, Zatloukal K, Denk H, Trauner M. Role of nuclear bile acid receptor, FXR, in adaptive ABC transporter regulation by cholic and ursodeoxycholic acid in mouse liver, kidney and intestine. J Hepatol 2003; 39:480-8. [PMID: 12971955 DOI: 10.1016/s0168-8278(03)00228-9] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND/AIMS Adaptive changes in transporter expression in liver and kidney provide alternative excretory pathways for biliary constituents during cholestasis and may thus attenuate liver injury. Whether adaptive changes in ATP-binding cassette (ABC) transporter expression are stimulated by bile acids and their nuclear receptor FXR is unknown. METHODS Hepatic, renal and intestinal ABC transporter expression was compared in cholic acid (CA)- and ursodeoxycholic acid (UDCA)-fed wild-type (FXR(+/+)) and FXR knock-out mice (FXR(-/-)). Expression was assessed by reverse transcription-polymerase chain reaction, immunoblotting and immunofluorescence microscopy. RESULTS CA feeding stimulated hepatic Mrp2, Mrp3, Bsep and renal Mrp2 as well as intestinal Mrp2 and Mrp3 expression. Lack of Bsep induction by CA in FXR(-/-) was associated with disseminated hepatocyte necrosis which was not prevented by compensatory induction of Mrp2 and Mrp3. With the exception of Bsep, UDCA stimulated expression of hepatic, renal and intestinal ABC transporters independent of FXR without inducing liver toxicity. CONCLUSIONS Toxic CA and non-toxic UDCA induce adaptive ABC transporter expression, independent of FXR with the exception of Bsep. Stimulation of hepatic Mrp3 as well as intestinal and renal Mrp2 by UDCA may contribute to its therapeutic effects by inducing alternative excretory routes for bile acids and other cholephiles.
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Affiliation(s)
- Gernot Zollner
- Division of Gastroenterology and Hepatology, Department of Medicine, Karl-Franzens University, Auenbruggerplatz 15, A-8036 Graz, Austria
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22
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Wagner M, Fickert P, Zollner G, Fuchsbichler A, Silbert D, Tsybrovskyy O, Zatloukal K, Guo GL, Schuetz JD, Gonzalez FJ, Marschall HU, Denk H, Trauner M. Role of farnesoid X receptor in determining hepatic ABC transporter expression and liver injury in bile duct-ligated mice. Gastroenterology 2003; 125:825-38. [PMID: 12949728 DOI: 10.1016/s0016-5085(03)01068-0] [Citation(s) in RCA: 205] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND & AIMS Cholestasis induces changes in hepatic adenosine triphosphate-binding cassette (ABC) transporter expression. We aimed to investigate the role of the nuclear bile acid receptor (farnesoid X receptor [FXR]) in mediating changes in ABC transporter expression and in determining liver injury. METHODS Hepatic ABC transporter (multidrug resistance-associated proteins [Mrp] 2-4 and bile salt export pump [Bsep]) expression and localization were studied in common bile duct-ligated (CBDL) FXR knockout (FXR(-/-)), wild-type (FXR(+/+)), and sham-operated mice. Serum alanine aminotransferase, alkaline phosphatase, bilirubin and bile acid levels, hepatic bile acid composition, and liver histology were investigated. Cholangiomanometry and bile duct morphometry were performed. RESULTS CBDL induced expression of Mrp 3 and Mrp 4 in FXR(+/+) and even more in FXR(-/-), whereas Mrp 2 expression remained unchanged. Bsep expression was maintained in CBDL FXR(+/+) but remained undetectable in CBDL FXR(-/-). Alanine aminotransferase levels and mortality rates did not differ between CBDL FXR(+/+) and FXR(-/-). CBDL increased biliary pressure and induced bile ductular proliferation and bile infarcts in FXR(+/+), whereas FXR(-/-) had lower biliary pressures, less ductular proliferation, and developed disseminated liver cell necroses. CONCLUSIONS Overexpression of Mrp 3 and Mrp 4 in CBDL mice is FXR independent and could play an important role in the adaptive hepatic ABC transporter response to cholestasis. Maintenance of Bsep expression strictly depends on FXR and is a critical determinant of the cholestatic phenotype. Lack of bile infarcts in CBDL FXR(-/-) suggests that development of bile infarcts is related to bile acid-dependent bile flow and biliary pressure. This information is relevant for the potential use of FXR modulators in the treatment of cholestatic liver diseases.
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Affiliation(s)
- Martin Wagner
- Department of Medicine, Karl-Franzens University, Graz, Austria
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23
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Zollner G, Fickert P, Silbert D, Fuchsbichler A, Marschall HU, Zatloukal K, Denk H, Trauner M. Adaptive changes in hepatobiliary transporter expression in primary biliary cirrhosis. J Hepatol 2003; 38:717-27. [PMID: 12763363 DOI: 10.1016/s0168-8278(03)00096-5] [Citation(s) in RCA: 191] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND/AIMS Information about alterations of hepatobiliary transporter expression in primary biliary cirrhosis (PBC) could provide important insights into the pathogenesis of cholestasis. This study aimed to determine the expression of hepatobiliary transport systems for bile salts (Na(+)/taurocholate cotransporter, NTCP; bile salt export pump, BSEP), organic anions (organic anion transporting protein, OATP2; canalicular conjugate export pump, MRP2; basolateral MRP homologue, MRP3), organic cations (canalicular multidrug export pump, MDR1), and phospholipids (canalicular phospholipid flippase MDR3) in livers from patients with advanced stages of PBC. METHODS Transporter mRNA and protein levels were assessed by reverse transcription polymerase chain reaction and Western blot analysis. Tissue distribution of transporters was investigated by immunohistochemistry and immunofluorescence microscopy. Hepatic bile acids were measured by gas chromatography-mass spectrometry. RESULTS Compared to controls, basolateral uptake systems (NTCP, OATP2) were reduced, canalicular export pumps for bile salts and bilirubin (BSEP, MRP2) were preserved, while canalicular MDR P-glycoproteins (MDR1, MDR3) and the basolateral efflux pump MRP3 were increased in PBC. Double immunofluorescence labeling with a canalicular marker (dipeptidyl peptidase IV) demonstrated proper canalicular localization of BSEP and MRP2 in PBC. OATP2 and MRP2 expression correlated inversely with hepatic levels of hydrophobic bile acids, while positively correlating with hepatic enrichment with ursodeoxycholic acid. CONCLUSIONS Down-regulation of basolateral uptake systems and maintenance/up-regulation of canalicular and basolateral efflux pumps may represent adaptive mechanisms limiting the accumulation of toxic biliary constituents.
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Affiliation(s)
- Gernot Zollner
- Division of Gastroenterology and Hepatology, Department of Medicine, Karl-Franzens University, Auenbruggerplatz 15, A-8036, Graz, Austria
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24
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Fickert P, Zollner G, Fuchsbichler A, Stumptner C, Weiglein AH, Lammert F, Marschall HU, Tsybrovskyy O, Zatloukal K, Denk H, Trauner M. Ursodeoxycholic acid aggravates bile infarcts in bile duct-ligated and Mdr2 knockout mice via disruption of cholangioles. Gastroenterology 2002; 123:1238-51. [PMID: 12360485 DOI: 10.1053/gast.2002.35948] [Citation(s) in RCA: 231] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS The effects of ursodeoxycholic acid (UDCA) in biliary obstruction are unclear. We aimed to determine the effects of UDCA in bile duct-ligated and in Mdr2 knockout (Mdr2(-/-)) mice with biliary strictures. METHODS Mice fed UDCA (0.5% wt/wt) or a control diet were subjected to common bile duct ligation (CBDL), selective bile duct ligation (SBDL), or sham operation. UDCA was also fed to 2-month-old Mdr2(-/-) mice. Serum biochemistry, liver histology, and mortality rates were investigated. The biliary tract was studied by plastination, India ink injection, and electron microscopy. The effects of UDCA on biliary pressure were determined by cholangiomanometry. RESULTS UDCA feeding in CBDL mice increased biliary pressure, with subsequent rupture of cholangioles and aggravation of hepatocyte necroses, resulting in significantly increased mortality. UDCA feeding in SBDL mice aggravated liver injury exclusively in the ligated lobe. Mdr2(-/-) mice developed liver lesions resembling sclerosing cholangitis characterized by biliary strictures and dilatations. UDCA induced bile infarcts in these animals. CONCLUSIONS UDCA aggravates bile infarcts and hepatocyte necroses in mice with biliary obstruction via disruption of cholangioles as a result of increased biliary pressure caused by its choleretic action.
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Affiliation(s)
- Peter Fickert
- Department of Medicine, Karl-Franzens University, Graz, Austria
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25
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Abstract
Further insights into the molecular regulation of bile acid transport and metabolism have provided the basis for a better understanding of the pathogenesis of cholestatic liver diseases. Novel insights into the mechanisms of action of ursodeoxycholic acid should advance our understanding of the treatment of cholestatic liver diseases. Mutations of transporter genes can cause hereditary cholestatic syndromes in both infants and adults as well as cholesterol gallstone disease. Important studies have been published on the pathogenesis, clinical features, and treatment of primary biliary cirrhosis, drug-induced cholestasis, and cholestasis of pregnancy.
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Affiliation(s)
- Michael Trauner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Karl-Franzens University, School of Medicine, Graz, Austria
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