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Camilleri M, BouSaba J. New Developments in Bile Acid Diarrhea. Gastroenterol Hepatol (N Y) 2023; 19:520-537. [PMID: 37771793 PMCID: PMC10524409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
Bile acid diarrhea (BAD) is characterized by increased frequency of bowel movements, looser stool consistency, urgency, and need for proximity to toilet facilities owing to the severity of the diarrhea, when compared with or relative to irritable bowel syndrome with diarrhea. Consequently, BAD leads to decreased quality of life. The condition is often misdiagnosed as irritable bowel syndrome with diarrhea or functional diarrhea. Patients with BAD have accelerated colonic transit, increased intestinal or colonic mucosal permeability, and altered stool microbiome composition associated with reduced dehydroxylation of primary to secondary bile acids. The established diagnostic test, selenium-75 homocholic acid taurine retention, is not available in the United States. Therefore, 48-hour fecal bile acid excretion has been the gold standard for diagnosis. With recent validation of combined measurement of primary bile acids in a single, random stool in addition to fasting serum 7α-hydroxy-4-cholesten-3-one, a practical point-of-care diagnostic test will soon be available. Randomized controlled trials have documented superiority of colesevelam to placebo and, in a separate study, superiority of the glucagon-like peptide 1 agonist liraglutide compared with colesevelam. Novel experimental approaches for BAD include farnesoid X receptor agonists and fibroblast growth factor 19 analogs. This article updates information on the pathophysiology, mechanisms, manifestations, diagnosis, and treatment of BAD.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Joelle BouSaba
- Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
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Tough IR, Lund ML, Patel BA, Schwartz TW, Cox HM. Paracrine relationship between incretin hormones and endogenous 5-hydroxytryptamine in the small and large intestine. Neurogastroenterol Motil 2023; 35:e14589. [PMID: 37010838 PMCID: PMC10909488 DOI: 10.1111/nmo.14589] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 02/13/2023] [Accepted: 03/21/2023] [Indexed: 04/04/2023]
Abstract
BACKGROUND Enterochromaffin (EC) cell-derived 5-hydroxytryptamine (5-HT) is a mediator of toxin-induced reflexes, initiating emesis via vagal and central 5-HT3 receptors. The amine is also involved in gastrointestinal (GI) reflexes that are prosecretory and promotile, and recently 5-HT's roles in chemosensation in the distal bowel have been described. We set out to establish the efficacy of 5-HT signaling, local 5-HT levels and pharmacology in discrete regions of the mouse small and large intestine. We also investigated the inter-relationships between incretin hormones, glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP) and endogenous 5-HT in mucosal and motility assays. METHODS Adult mouse GI mucosae were mounted in Ussing chambers and area-specific studies were performed to establish the 5-HT3 and 5-HT4 pharmacology, the sidedness of responses, and the inter-relationships between incretins and endogenous 5-HT. Natural fecal pellet transit in vitro and full-length GI transit in vivo were also measured. KEY RESULTS We observed the greatest level of tonic and exogenous 5-HT-induced ion transport and highest levels of 5-HT in ascending colon mucosa. Here both 5-HT3 and 5-HT4 receptors were involved but elsewhere in the GI tract epithelial basolateral 5-HT4 receptors mediate 5-HT's prosecretory effect. Exendin-4 and GIP induced 5-HT release in the ascending colon, while L cell-derived PYY also contributed to GIP mucosal effects in the descending colon. Both peptides slowed colonic transit. CONCLUSIONS & INFERENCES We provide functional evidence for paracrine interplay between 5-HT, GLP-1 and GIP, particularly in the colonic mucosal region. Basolateral epithelial 5-HT4 receptors mediated both 5-HT and incretin mucosal responses in healthy colon.
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Affiliation(s)
- Iain R. Tough
- Wolfson Centre for Age‐Related Diseases, Institute of Psychology, Psychiatry and NeuroscienceKing's College LondonHodgkin Building, Guy's CampusLondonSE1 1ULUK
| | - Mari L. Lund
- The Novo Nordisk Foundation Centre for Basic Metabolic Research, Section for Metabolic Receptology and EnteroendocrinologyUniversity of CopenhagenCopenhagenDK‐2200Denmark
- Present address:
Chr. Hansen A/S, Human Health ResearchHoersholmDK‐2970Denmark
| | - Bhavik A. Patel
- Centre for Stress and Age‐Related Diseases, School of Applied SciencesUniversity of BrightonBrightonUK
| | - Thue W. Schwartz
- The Novo Nordisk Foundation Centre for Basic Metabolic Research, Section for Metabolic Receptology and EnteroendocrinologyUniversity of CopenhagenCopenhagenDK‐2200Denmark
| | - Helen M. Cox
- Wolfson Centre for Age‐Related Diseases, Institute of Psychology, Psychiatry and NeuroscienceKing's College LondonHodgkin Building, Guy's CampusLondonSE1 1ULUK
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Abstract
PURPOSE OF REVIEW Bile acid diarrhea (BAD) is a common but under-recognized gastrointestinal condition that manifests with increased stool frequency and urgency, and a looser stool consistency. The aim of this review is to present recent advances in the pathophysiology, mechanisms, manifestations, diagnosis, and treatment of BAD. RECENT FINDINGS Patients with BAD have evidence of accelerated colonic transit, increased gut mucosal permeability, altered stool microbiome composition, and decreased quality of life. Single, random stool measurements of bile acids, alone or in combination with fasting serum 7-alpha-hydroxy-4-cholesten-3-one, have shown good sensitivity and specificity for the diagnosis of BAD. Novel therapeutic approaches include farnesoid X receptor agonists and glucagon-like peptide 1 agonists. SUMMARY Recent research has led to a better understanding of the pathophysiology and mechanisms of BAD, which might pave the way towards more targeted treatment strategies for BAD. Newer, more affordable, and easier diagnostic methods facilitate the diagnosis of BAD.
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Affiliation(s)
- Joelle BouSaba
- Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
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Keely SJ, Barrett KE. Intestinal secretory mechanisms and diarrhea. Am J Physiol Gastrointest Liver Physiol 2022; 322:G405-G420. [PMID: 35170355 PMCID: PMC8917926 DOI: 10.1152/ajpgi.00316.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 01/31/2023]
Abstract
One of the primary functions of the intestinal epithelium is to transport fluid and electrolytes to and from the luminal contents. Under normal circumstances, absorptive and secretory processes are tightly regulated such that absorption predominates, thereby enabling conservation of the large volumes of water that pass through the intestine each day. However, in conditions of secretory diarrhea, this balance becomes dysregulated, so that fluid secretion, driven primarily by Cl- secretion, overwhelms absorptive capacity, leading to increased loss of water in the stool. Secretory diarrheas are common and include those induced by pathogenic bacteria and viruses, allergens, and disruptions to bile acid homeostasis, or as a side effect of many drugs. Here, we review the cellular and molecular mechanisms by which Cl- and fluid secretion in the intestine are regulated, how these mechanisms become dysregulated in conditions of secretory diarrhea, currently available and emerging therapeutic approaches, and how new strategies to exploit intestinal secretory mechanisms are successfully being used in the treatment of constipation.
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Affiliation(s)
- Stephen J Keely
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | - Kim E Barrett
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, California
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, California
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Keely SJ, Urso A, Ilyaskin AV, Korbmacher C, Bunnett NW, Poole DP, Carbone SE. Contributions of bile acids to gastrointestinal physiology as receptor agonists and modifiers of ion channels. Am J Physiol Gastrointest Liver Physiol 2022; 322:G201-G222. [PMID: 34755536 PMCID: PMC8782647 DOI: 10.1152/ajpgi.00125.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 10/28/2021] [Accepted: 11/08/2021] [Indexed: 02/03/2023]
Abstract
Bile acids (BAs) are known to be important regulators of intestinal motility and epithelial fluid and electrolyte transport. Over the past two decades, significant advances in identifying and characterizing the receptors, transporters, and ion channels targeted by BAs have led to exciting new insights into the molecular mechanisms involved in these processes. Our appreciation of BAs, their receptors, and BA-modulated ion channels as potential targets for the development of new approaches to treat intestinal motility and transport disorders is increasing. In the current review, we aim to summarize recent advances in our knowledge of the different BA receptors and BA-modulated ion channels present in the gastrointestinal system. We discuss how they regulate motility and epithelial transport, their roles in pathogenesis, and their therapeutic potential in a range of gastrointestinal diseases.
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Affiliation(s)
- Stephen J Keely
- Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin, Ireland
| | - Andreacarola Urso
- Department of Surgery, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York
- Department of Pharmacology, Columbia University, New York, New York
| | - Alexandr V Ilyaskin
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander University Erlangen-Nürnberg, Bavaria, Germany
| | - Christoph Korbmacher
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander University Erlangen-Nürnberg, Bavaria, Germany
| | - Nigel W Bunnett
- Department of Molecular Pathobiology, Neuroscience Institute, New York University, New York, New York
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University, New York, New York
| | - Daniel P Poole
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Australian Research Council, Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Simona E Carbone
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Australian Research Council, Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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Kuwahara A, Matsuda K, Kuwahara Y, Asano S, Inui T, Marunaka Y. Microbiota-gut-brain axis: enteroendocrine cells and the enteric nervous system form an interface between the microbiota and the central nervous system. Biomed Res 2021; 41:199-216. [PMID: 33071256 DOI: 10.2220/biomedres.41.199] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The microbiota-gut-brain axis transmits bidirectional communication between the gut and the central nervous system and links the emotional and cognitive centers of the brain with peripheral gut functions. This communication occurs along the axis via local, paracrine, and endocrine mechanisms involving a variety of gut-derived peptide/amine produced by enteroendocrine cells. Neural networks, such as the enteric nervous system, and the central nervous system, including the autonomic nervous system, also transmit information through the microbiota-gut-brain axis. Recent advances in research have described the importance of the gut microbiota in influencing normal physiology and contributing to disease. We are only beginning to understand this bidirectional communication system. In this review, we summarize the available data supporting the existence of these interactions, highlighting data related to the contribution of enteroendocrine cells and the enteric nervous system as an interface between the gut microbiota and brain.
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Affiliation(s)
- Atsukazu Kuwahara
- Research Unit for Epithelial Physiology and Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, Ritsumeikan University
| | - Kyoko Matsuda
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University
| | - Yuko Kuwahara
- Research Unit for Epithelial Physiology and Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, Ritsumeikan University
| | - Shinji Asano
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University
| | | | - Yoshinori Marunaka
- Research Unit for Epithelial Physiology and Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, Ritsumeikan University.,Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine.,Research Institute for Clinical Physiology, Kyoto Industrial Health Association
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Sun R, Xu C, Feng B, Gao X, Liu Z. Critical roles of bile acids in regulating intestinal mucosal immune responses. Therap Adv Gastroenterol 2021; 14:17562848211018098. [PMID: 34104213 PMCID: PMC8165529 DOI: 10.1177/17562848211018098] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 04/27/2021] [Indexed: 02/04/2023] Open
Abstract
Bile acids are a class of cholesterol derivatives that have been known for a long time for their critical roles in facilitating the digestion and absorption of lipid from the daily diet. The transformation of primary bile acids produced by the liver to secondary bile acids appears under the action of microbiota in the intestine, greatly expanding the molecular diversity of the intestinal environment. With the discovery of several new receptors of bile acids and signaling pathways, bile acids are considered as a family of important metabolites that play pleiotropic roles in regulating many aspects of human overall health, especially in the maintenance of the microbiota homeostasis and the balance of the mucosal immune system in the intestine. Accordingly, disruption of the process involved in the metabolism or circulation of bile acids is implicated in many disorders that mainly affect the intestine, such as inflammatory bowel disease and colon cancer. In this review, we discuss the different metabolism profiles in diseases associated with the intestinal mucosa and the diverse roles of bile acids in regulating the intestinal immune system. Furthermore, we also summarize recent advances in the field of new drugs that target bile acid signaling and highlight the importance of bile acids as a new target for disease intervention.
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Affiliation(s)
| | | | | | - Xiang Gao
- Department of Gastroenterology, The Shanghai Tenth People’s Hospital of Tongji University, Shanghai, China
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Tough IR, Schwartz TW, Cox HM. Synthetic G protein-coupled bile acid receptor agonists and bile acids act via basolateral receptors in ileal and colonic mucosa. Neurogastroenterol Motil 2020; 32:e13943. [PMID: 32656959 DOI: 10.1111/nmo.13943] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/29/2020] [Accepted: 06/22/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND The G protein-coupled bile acid (BA) receptor, GPBA (previously named TGR5), mediates BA gastrointestinal (GI) activities. Our aim was to elucidate the mucosal and motility responses to selective GPBA agonists compared with conjugated BA (eg, taurodeoxycholate, TDCA) in mouse and human colon. METHODS Ion transport responses to GPBA agonists or BAs were measured in mucosal preparations with intact submucous innervation, from C57Bl/6, PYY-/-, or GPBA-/- mice and compared with GPBA signaling in human colon. We also investigated the mechanisms underlying GPBA agonism in mucosae and on natural fecal pellet propulsion. KEY RESULTS GPBA agonist Merck V stimulated basolateral responses involving peptide YY (PYY), cholinergic, and 5-HT mechanisms in colonic mucosa. The PYY-mediated GPBA signal was glucose-sensitive. Luminal TDCA crossed the epithelial lining via the apical sodium-dependent BA transporter (ASBT) and its inhibitor, GSK2330672 significantly reduced luminal, but not basolateral TDCA activity. Merck V also slowed natural fecal pellet progression in wild-type and PYY-/- colons but not in GPBA-/- colon, while TDCA increased motility in wild-type colon. The antimotile GPBA effect was reversed by blockade of glucagon-like peptide 1 (GLP-1) receptors or nitric oxide synthase, indicating involvement of GLP-1 and nitric oxide. CONCLUSIONS & INFERENCES We conclude that several different targets within the lamina propria express GPBA, including L cells (that release PYY and GLP-1), enterochromaffin cells and neurons (that release 5-HT), and other enteric neurons. Furthermore, luminal-conjugated BAs require transport across the epithelium via ASBT in order to activate basolateral GPBA.
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Affiliation(s)
- Iain R Tough
- King's College London, Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, London, UK
| | - Thue W Schwartz
- Novo Nordisk Foundation Centre for Basic Metabolic Research, Section for Metabolic Receptology and Enteroendocrinology, University of Copenhagen, Copenhagen, Denmark
| | - Helen M Cox
- King's College London, Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, London, UK
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9
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Abstract
Bile acids (BAs) are the central signals in enterohepatic communication, and they also integrate microbiota-derived signals into enterohepatic signaling. The tissue distribution and signaling pathways activated by BAs through natural receptors, farsenoid X receptor and G protein-coupled BA receptor 1 (GPBAR1, also known as Takeda G-coupled receptor 5), have led to a greater understanding of the mechanisms and potential therapeutic agents. BA diarrhea is most commonly encountered in ileal resection or disease, in idiopathic disorders (with presentation similar to functional diarrhea or irritable bowel syndrome with diarrhea), and in association with malabsorption such as chronic pancreatitis or celiac disease. Diagnosis of BA diarrhea is based on Se-homocholic acid taurine retention, 48-hour fecal BA excretion, or serum 7αC4; the latter being a marker of hepatic BA synthesis. BA diarrhea tends to be associated with higher body mass index, increased stool weight and stool fat, and acceleration of colonic transit. Biochemical markers of increased BA synthesis or excretion are available through reference laboratories. Current treatment of BA diarrhea is based on BA sequestrants, and, in the future, it is anticipated that farsenoid X receptor agonists may also be effective. The optimal conditions for an empiric trial with BA sequestrants as a diagnostic test are still unclear. However, such therapeutic trials are widely used in clinical practice. Some national guidelines recommend definitive diagnosis of BA diarrhea over empirical trial.
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Bellier JP, Yuan PQ, Mukaisho K, Tooyama I, Taché Y, Kimura H. A Novel Antiserum Against a Predicted Human Peripheral Choline Acetyltransferase (hpChAT) for Labeling Neuronal Structures in Human Colon. Front Neuroanat 2019; 13:37. [PMID: 31040770 PMCID: PMC6476985 DOI: 10.3389/fnana.2019.00037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 03/08/2019] [Indexed: 12/13/2022] Open
Abstract
Choline acetyltransferase (ChAT), the enzyme synthesizing acetylcholine (ACh), has an exon-skipping splice variant which is expressed preferentially in the peripheral nervous system (PNS) and thus termed peripheral ChAT (pChAT). A rabbit antiserum previously produced against rat pChAT (rpChAT) has been used for immunohistochemistry (IHC) to study peripheral cholinergic structures in various animals. The present study was undertaken to develop a specific antiserum against a predicted human pChAT (hpChAT) protein. A novel mouse antiserum has been successfully raised against a unique 14-amino acid sequence of hpChAT protein. Our Western blot using this antiserum (termed here anti-hpChAT serum) on human colon extracts revealed only a single band of 47 kDa, matching the deduced size of hpChAT protein. By IHC, the antiserum gave intense staining in many neuronal cells and fibers of human colon but not brain, and such a pattern of staining seemed identical with that reported in colon of various animals using anti-rpChAT serum. In the antibody-absorption test, hpChAT-immunoreactive staining in human colon was completely blocked by using the antiserum pre-absorbed with the antigen peptide. Double immunofluorescence in human colon moreover indicated that structures stained with anti-hpChAT were also stained with anti-rpChAT, and vice versa. hpChAT antiserum allowed the identification of cell types, as Dogiel type cells in intramural plexuses, and fiber innervation of colon muscles and mucosae. The present results demonstrate the specificity and reliability of the hpChAT antiserum as a novel tool for immunohistochemical studies in human colon, opening venues to map cholinergic innervation in other human PNS tissues.
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Affiliation(s)
- Jean-Pierre Bellier
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Japan
| | - Pu-Qing Yuan
- CURE/Digestive Diseases Research Center, Vatche and Tamar Manoukian Digestive Diseases Division, Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, United States.,VA Greater Los Angeles Health System, Los Angeles, CA, United States
| | - Kenichi Mukaisho
- Department of Pathology, Shiga University of Medical Science, Otsu, Japan
| | - Ikuo Tooyama
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Japan
| | - Yvette Taché
- CURE/Digestive Diseases Research Center, Vatche and Tamar Manoukian Digestive Diseases Division, Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, United States.,VA Greater Los Angeles Health System, Los Angeles, CA, United States
| | - Hiroshi Kimura
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Japan
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Ticho AL, Malhotra P, Dudeja PK, Gill RK, Alrefai WA. Bile Acid Receptors and Gastrointestinal Functions. LIVER RESEARCH 2019; 3:31-39. [PMID: 32368358 PMCID: PMC7197881 DOI: 10.1016/j.livres.2019.01.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bile acids modulate several gastrointestinal functions including electrolyte secretion and absorption, gastric emptying, and small intestinal and colonic motility. High concentrations of bile acids lead to diarrhea and are implicated in the development of esophageal, gastric and colonic cancer. Alterations in bile acid homeostasis are also implicated in the pathophysiology of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Our understanding of the mechanisms underlying these effects of bile acids on gut functions has been greatly enhanced by the discovery of bile acid receptors, including the nuclear receptors: farnesoid X receptor (FXR), vitamin D receptor (VDR), pregnane X receptor (PXR), and constitutive androstane receptor (CAR); and the G protein-coupled receptors: Takeda G protein-coupled receptor (TGR5), sphingosine-1-phosphate receptor 2 (S1PR2), and muscarinic acetylcholine receptor M3 (M3R).. For example, various studies provided evidence demonstrating the anti-inflammatory effects FXR and TGR5 activation in models of intestinal inflammation. In addition, TGR5 activation in enteric neurons was recently shown to increase colonic motility, which may lead to bile acid-induced diarrhea. Interestingly, TGR5 induces the secretion of glucagon-like peptide-1 (GLP-1) from L-cells to enhance insulin secretion and modulate glucose metabolism. Because of the importance of these receptors, agonists of TGR5 and intestine-specific FXR agonists are currently being tested as an option for the treatment of diabetes mellitus and primary bile acid diarrhea, respectively. This review summarizes current knowledge of the functional roles of bile acid receptors in the gastrointestinal tract.
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Affiliation(s)
- Alexander L. Ticho
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago
| | - Pooja Malhotra
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago
| | - Pradeep K. Dudeja
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago,Jesse Brown VA Medical Center, Chicago, IL
| | - Ravinder K. Gill
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago
| | - Waddah A. Alrefai
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago,Jesse Brown VA Medical Center, Chicago, IL,To whom correspondence should be addressed: Waddah A. Alrefai, MD: Research Career Scientist, Jesse Brown VA Medical Center, Professor of Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612; ; Tel. (312) 569-7429; Fax. (312) 569-8114
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12
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Hegyi P, Maléth J, Walters JR, Hofmann AF, Keely SJ. Guts and Gall: Bile Acids in Regulation of Intestinal Epithelial Function in Health and Disease. Physiol Rev 2019; 98:1983-2023. [PMID: 30067158 DOI: 10.1152/physrev.00054.2017] [Citation(s) in RCA: 164] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Epithelial cells line the entire surface of the gastrointestinal tract and its accessory organs where they primarily function in transporting digestive enzymes, nutrients, electrolytes, and fluid to and from the luminal contents. At the same time, epithelial cells are responsible for forming a physical and biochemical barrier that prevents the entry into the body of harmful agents, such as bacteria and their toxins. Dysregulation of epithelial transport and barrier function is associated with the pathogenesis of a number of conditions throughout the intestine, such as inflammatory bowel disease, chronic diarrhea, pancreatitis, reflux esophagitis, and cancer. Driven by discovery of specific receptors on intestinal epithelial cells, new insights into mechanisms that control their synthesis and enterohepatic circulation, and a growing appreciation of their roles as bioactive bacterial metabolites, bile acids are currently receiving a great deal of interest as critical regulators of epithelial function in health and disease. This review aims to summarize recent advances in this field and to highlight how bile acids are now emerging as exciting new targets for disease intervention.
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Affiliation(s)
- Peter Hegyi
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Joszef Maléth
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Julian R Walters
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Alan F Hofmann
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Stephen J Keely
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
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Abstract
INTRODUCTION Chronic idiopathic constipation (CC) is highly prevalent worldwide. A subset of patients with CC have reduced fecal (and by inference, intra-colonic) bile acids (BA). Elobixibat, a locally-acting ileal bile acid transporter (IBAT) inhibitor, leads to increased BA delivery to the colon and represents a new class of treatment for CC. BAs accelerate colonic transit and increase colonic secretion. Therefore, IBAT inhibitors have potential to treat patients with CC. Areas covered: Rationale for IBAT inhibitor in therapeutics, and preclinical and clinical pharmacology of elobixibat: In vitro, elobixibat is a highly potent, selective IBAT inhibitor. In humans, elobixibat accelerated colonic transit. In phase 2A, 2B and 3 studies in CC, elobixibat was efficacious, well tolerated and safe. An open-label, phase 3 trial (52 weeks) confirmed the safety of elobixibat. Elobixibat reduces LDL cholesterol, increases serum GLP-1, and has potential in metabolic syndrome. Expert commentary: Uniquely among current treatments of CC, elobixibat stimulates both motor and secretory functions in the colon. These dual effects suggest that, when approved, elobixibat may be a first-line choice for constipation associated with colonic BA deficiency and a second-line treatment for all patients with CC and constipation-predominant irritable bowel syndrome. Further studies are required to confirm efficacy for relief of CC. Once approved, elobixibat will likely become a second-line choice for treatment of CC.
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Affiliation(s)
- Victor Chedid
- a Division of Gastroenterology and Hepatology , Mayo Clinic , Rochester , MN , USA
| | - Priya Vijayvargiya
- a Division of Gastroenterology and Hepatology , Mayo Clinic , Rochester , MN , USA
| | - Michael Camilleri
- a Division of Gastroenterology and Hepatology , Mayo Clinic , Rochester , MN , USA
- b Pharmacology, and Physiology , Mayo Clinic College of Medicine and Science, ConsultantDivision of Gastroenterology and Hepatology, Mayo Clinic , Rochester , MN , USA
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14
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Abstract
PURPOSE OF REVIEW To provide an update on the prevalence, pathophysiology, disease associations, and treatment options for bile acid malabsorption (BAM). RECENT FINDINGS •Molecular mechanisms-BAs prevent water reabsorption and increase water secretion by intracellular mediators, increasing aquaporin channels and intracellular permeability. •Inflammatory bowel disease-new molecular mechanisms of BAM are identified in patients without ileal disease, including changes in expression of ileal BA transporter and nuclear receptors involved in BA homeostasis. •Microscopic colitis-BAM is one of the mechanisms leading to microscopic colitis. •Diagnostic testing-new diagnostic tests have been launched in the USA (serum C4 and fecal 48-h BA excretion); stimulated FGF19 has higher detection of BAM compared to fasting sample alone. •Treatment-investigational FXR agonists may provide a daily, oral option for treatment of BAM instead of BA sequestrants. There is a greater appreciation of the biological role of bile acids across multiple fields of medicine, including gastrointestinal indications.
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Affiliation(s)
- Priya Vijayvargiya
- Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER), Division of Gastroenterology and Hepatology, Mayo Clinic, Charlton Bldg., Rm. 8-110, 200 First Street S.W, Rochester, MN, 55905, USA
| | - Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER), Division of Gastroenterology and Hepatology, Mayo Clinic, Charlton Bldg., Rm. 8-110, 200 First Street S.W, Rochester, MN, 55905, USA.
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15
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Tian J, Huang S, Sun S, Ding L, Zhang E, Huang W. Bile acid signaling and bariatric surgery. LIVER RESEARCH 2017; 1:208-213. [PMID: 30034914 PMCID: PMC6051716 DOI: 10.1016/j.livres.2017.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The rapid worldwide rise in obesity rates over the past few decades imposes an urgent need to develop effective strategies for treating obesity and associated metabolic complications. Bariatric surgical procedures, such as Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG), currently provide the most effective treatment for obesity and type 2 diabetes (T2D), as well as for non-alcoholic steatohepatitis (NASH). However, the underlying mechanisms of the beneficial effects of bariatric surgery remain elusive. Recent studies have identified bile acids as potential signaling molecules involved in the beneficial effects of bariatric surgery. This review focuses on the most recent studies on the roles of bile acids and bile acid receptors Farnesoid X receptor (FXR) and G protein-coupled bile acid receptor 5 (TGR5) in bariatric surgery. We also discuss the possibility of modulating bile acid signaling as a pharmacological therapeutic approach to treating obesity and its associated metabolic complications.
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Affiliation(s)
- Jingyan Tian
- National Clinical Research Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Diabetes Complications and Metabolism, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Silvia Huang
- Eugene Robert Summer Program, City of Hope, Duarte, CA, USA
| | - Siming Sun
- Department of Diabetes Complications and Metabolism, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Lili Ding
- Department of Diabetes Complications and Metabolism, Beckman Research Institute of City of Hope, Duarte, CA, USA
- Shanghai Key Laboratory of Compound Chinese Medicines and the Ministry of Education (MOE) Key Laboratory of Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Eryun Zhang
- Department of Diabetes Complications and Metabolism, Beckman Research Institute of City of Hope, Duarte, CA, USA
- Shanghai Key Laboratory of Compound Chinese Medicines and the Ministry of Education (MOE) Key Laboratory of Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Wendong Huang
- Department of Diabetes Complications and Metabolism, Beckman Research Institute of City of Hope, Duarte, CA, USA
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