1
|
Portincasa P, Di Ciaula A, Bonfrate L, Stella A, Garruti G, Lamont JT. Metabolic dysfunction-associated gallstone disease: expecting more from critical care manifestations. Intern Emerg Med 2023; 18:1897-1918. [PMID: 37455265 PMCID: PMC10543156 DOI: 10.1007/s11739-023-03355-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 06/22/2023] [Indexed: 07/18/2023]
Abstract
About 20% of adults worldwide have gallstones which are solid conglomerates in the biliary tree made of cholesterol monohydrate crystals, mucin, calcium bilirubinate, and protein aggregates. About 20% of gallstone patients will definitively develop gallstone disease, a condition which consists of gallstone-related symptoms and/or complications requiring medical therapy, endoscopic procedures, and/or cholecystectomy. Gallstones represent one of the most prevalent digestive disorders in Western countries and patients with gallstone disease are one of the largest categories admitted to European hospitals. About 80% of gallstones in Western countries are made of cholesterol due to disturbed cholesterol homeostasis which involves the liver, the gallbladder and the intestine on a genetic background. The incidence of cholesterol gallstones is dramatically increasing in parallel with the global epidemic of insulin resistance, type 2 diabetes, expansion of visceral adiposity, obesity, and metabolic syndrome. In this context, gallstones can be largely considered a metabolic dysfunction-associated gallstone disease, a condition prone to specific and systemic preventive measures. In this review we discuss the key pathogenic and clinical aspects of gallstones, as the main clinical consequences of metabolic dysfunction-associated disease.
Collapse
Affiliation(s)
- Piero Portincasa
- Clinica Medica "A. Murri", Division of Internal Medicine, Department of Preventive and Regenerative Medicine and Ionian Area (DiMePrev-J), University of Bari Aldo Moro, p.zza Giulio Cesare 11, 70124, Bari, Italy.
| | - Agostino Di Ciaula
- Clinica Medica "A. Murri", Division of Internal Medicine, Department of Preventive and Regenerative Medicine and Ionian Area (DiMePrev-J), University of Bari Aldo Moro, p.zza Giulio Cesare 11, 70124, Bari, Italy
| | - Leonilde Bonfrate
- Clinica Medica "A. Murri", Division of Internal Medicine, Department of Preventive and Regenerative Medicine and Ionian Area (DiMePrev-J), University of Bari Aldo Moro, p.zza Giulio Cesare 11, 70124, Bari, Italy
| | - Alessandro Stella
- Laboratory of Medical Genetics, Department of Precision and Regenerative Medicine and Ionian Area (DIMEPRE-J), University of Bari Aldo Moro, Bari, Italy
| | - Gabriella Garruti
- Section of Endocrinology, Department of Preventive and Regenerative Medicine and Ionian Area (DiMePrev-J), University of Bari Aldo Moro, Bari, Italy
| | - John Thomas Lamont
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, 02215, USA
| |
Collapse
|
2
|
Yin X, Chan LS, Bose D, Jackson AU, VandeHaar P, Locke AE, Fuchsberger C, Stringham HM, Welch R, Yu K, Fernandes Silva L, Service SK, Zhang D, Hector EC, Young E, Ganel L, Das I, Abel H, Erdos MR, Bonnycastle LL, Kuusisto J, Stitziel NO, Hall IM, Wagner GR, Kang J, Morrison J, Burant CF, Collins FS, Ripatti S, Palotie A, Freimer NB, Mohlke KL, Scott LJ, Wen X, Fauman EB, Laakso M, Boehnke M. Genome-wide association studies of metabolites in Finnish men identify disease-relevant loci. Nat Commun 2022; 13:1644. [PMID: 35347128 PMCID: PMC8960770 DOI: 10.1038/s41467-022-29143-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 02/23/2022] [Indexed: 01/13/2023] Open
Abstract
Few studies have explored the impact of rare variants (minor allele frequency < 1%) on highly heritable plasma metabolites identified in metabolomic screens. The Finnish population provides an ideal opportunity for such explorations, given the multiple bottlenecks and expansions that have shaped its history, and the enrichment for many otherwise rare alleles that has resulted. Here, we report genetic associations for 1391 plasma metabolites in 6136 men from the late-settlement region of Finland. We identify 303 novel association signals, more than one third at variants rare or enriched in Finns. Many of these signals identify genes not previously implicated in metabolite genome-wide association studies and suggest mechanisms for diseases and disease-related traits.
Collapse
Affiliation(s)
- Xianyong Yin
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Lap Sum Chan
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Debraj Bose
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Anne U Jackson
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Peter VandeHaar
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Adam E Locke
- McDonnell Genome Institute, Washington University School of Medicine, St Louis, MO, 63108, USA
| | - Christian Fuchsberger
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
- Institute for Biomedicine, Eurac Research, Bolzano, 39100, Italy
| | - Heather M Stringham
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Ryan Welch
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Ketian Yu
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Lilian Fernandes Silva
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, 70210, Finland
| | - Susan K Service
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, 90024, USA
| | - Daiwei Zhang
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Emily C Hector
- Department of Statistics, North Carolina State University, Raleigh, NC, 27695, USA
| | - Erica Young
- McDonnell Genome Institute, Washington University School of Medicine, St Louis, MO, 63108, USA
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Liron Ganel
- McDonnell Genome Institute, Washington University School of Medicine, St Louis, MO, 63108, USA
| | - Indraniel Das
- McDonnell Genome Institute, Washington University School of Medicine, St Louis, MO, 63108, USA
| | - Haley Abel
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Michael R Erdos
- Molecular Genetics Section, Center for Precision Health Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Lori L Bonnycastle
- Molecular Genetics Section, Center for Precision Health Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Johanna Kuusisto
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, 70210, Finland
- Center for Medicine and Clinical Research, Kuopio University Hospital, Kuopio, 70210, Finland
| | - Nathan O Stitziel
- McDonnell Genome Institute, Washington University School of Medicine, St Louis, MO, 63108, USA
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St Louis, MO, 63110, USA
- Department of Genetics, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Ira M Hall
- Center for Genomic Health, Department of Genetics, Yale University, New Haven, CT, 06510, USA
| | | | - Jian Kang
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Jean Morrison
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Charles F Burant
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Francis S Collins
- Molecular Genetics Section, Center for Precision Health Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Samuli Ripatti
- Institute for Molecular Medicine Finland, FIMM, HiLIFE, University of Helsinki, Helsinki, 00290, Finland
- Department of Public Health, University of Helsinki, Helsinki, 00014, Finland
- Broad Institute of MIT & Harvard, Cambridge, MA, 02142, USA
| | - Aarno Palotie
- Institute for Molecular Medicine Finland, FIMM, HiLIFE, University of Helsinki, Helsinki, 00290, Finland
- Department of Public Health, University of Helsinki, Helsinki, 00014, Finland
- Analytic and Translational Genetics Unit, Department of Medicine, Department of Neurology, and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Nelson B Freimer
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, 90024, USA
| | - Karen L Mohlke
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Laura J Scott
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Xiaoquan Wen
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA
| | - Eric B Fauman
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development and Medical, Cambridge, MA, 02139, USA.
| | - Markku Laakso
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, Kuopio, 70210, Finland.
| | - Michael Boehnke
- Department of Biostatistics and Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA.
| |
Collapse
|
3
|
Gaillard D, Masson D, Garo E, Souidi M, Pais de Barros JP, Schoonjans K, Grober J, Besnard P, Thomas C. Muricholic Acids Promote Resistance to Hypercholesterolemia in Cholesterol-Fed Mice. Int J Mol Sci 2021; 22:7163. [PMID: 34281217 PMCID: PMC8269105 DOI: 10.3390/ijms22137163] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND AIMS Hypercholesterolemia is a major risk factor for atherosclerosis and cardiovascular diseases. Although resistant to hypercholesterolemia, the mouse is a prominent model in cardiovascular research. To assess the contribution of bile acids to this protective phenotype, we explored the impact of a 2-week-long dietary cholesterol overload on cholesterol and bile acid metabolism in mice. METHODS Bile acid, oxysterol, and cholesterol metabolism and transport were assessed by quantitative real-time PCR, western blotting, GC-MS/MS, or enzymatic assays in the liver, the gut, the kidney, as well as in the feces, the blood, and the urine. RESULTS Plasma triglycerides and cholesterol levels were unchanged in mice fed a cholesterol-rich diet that contained 100-fold more cholesterol than the standard diet. In the liver, oxysterol-mediated LXR activation stimulated the synthesis of bile acids and in particular increased the levels of hydrophilic muricholic acids, which in turn reduced FXR signaling, as assessed in vivo with Fxr reporter mice. Consequently, biliary and basolateral excretions of bile acids and cholesterol were increased, whereas portal uptake was reduced. Furthermore, we observed a reduction in intestinal and renal bile acid absorption. CONCLUSIONS These coordinated events are mediated by increased muricholic acid levels which inhibit FXR signaling in favor of LXR and SREBP2 signaling to promote efficient fecal and urinary elimination of cholesterol and neo-synthesized bile acids. Therefore, our data suggest that enhancement of the hydrophilic bile acid pool following a cholesterol overload may contribute to the resistance to hypercholesterolemia in mice. This work paves the way for new therapeutic opportunities using hydrophilic bile acid supplementation to mitigate hypercholesterolemia.
Collapse
Affiliation(s)
- Dany Gaillard
- Center for Translational Medicine, UMR1231 INSERM-uB-AgroSupDijon, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France; (D.G.); (D.M.); (J.-P.P.d.B.); (J.G.)
- Department of Cell & Developmental Biology, and The Rocky Mountain Taste & Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - David Masson
- Center for Translational Medicine, UMR1231 INSERM-uB-AgroSupDijon, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France; (D.G.); (D.M.); (J.-P.P.d.B.); (J.G.)
- LipSTIC LabEx, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France
- Biochemistry Department, University Hospital François Mitterrand, 21000 Dijon, France
| | - Erwan Garo
- IGBMC, CNRS UMR 7104, INSERM U 1258, 67400 Illkirch, France;
| | - Maamar Souidi
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), 92260 Fontenay-aux-Roses, France;
| | - Jean-Paul Pais de Barros
- Center for Translational Medicine, UMR1231 INSERM-uB-AgroSupDijon, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France; (D.G.); (D.M.); (J.-P.P.d.B.); (J.G.)
- LipSTIC LabEx, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France
- Lipidomic Facility, Université de Bourgogne Franche-Comté (UBFC), 21078 Dijon, France
| | - Kristina Schoonjans
- Institute of Bioengineering, Life Science Faculty, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland;
| | - Jacques Grober
- Center for Translational Medicine, UMR1231 INSERM-uB-AgroSupDijon, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France; (D.G.); (D.M.); (J.-P.P.d.B.); (J.G.)
- LipSTIC LabEx, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France
| | - Philippe Besnard
- Center for Translational Medicine, UMR1231 INSERM-uB-AgroSupDijon, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France; (D.G.); (D.M.); (J.-P.P.d.B.); (J.G.)
- LipSTIC LabEx, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France
- Physiologie de la Nutrition, AgroSup Dijon, 21000 Dijon, France
| | - Charles Thomas
- Center for Translational Medicine, UMR1231 INSERM-uB-AgroSupDijon, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France; (D.G.); (D.M.); (J.-P.P.d.B.); (J.G.)
- LipSTIC LabEx, Université de Bourgogne Franche-Comté (UBFC), 21000 Dijon, France
| |
Collapse
|
4
|
Wang HH, Portincasa P, Liu M, Tso P, Wang DQH. An Update on the Lithogenic Mechanisms of Cholecystokinin a Receptor (CCKAR), an Important Gallstone Gene for Lith13. Genes (Basel) 2020; 11:E1438. [PMID: 33260332 PMCID: PMC7761502 DOI: 10.3390/genes11121438] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 11/23/2020] [Accepted: 11/27/2020] [Indexed: 12/15/2022] Open
Abstract
The cholecystokinin A receptor (CCKAR) is expressed predominantly in the gallbladder and small intestine in the digestive system, where it is responsible for CCK's regulation of gallbladder and small intestinal motility. The effect of CCKAR on small intestinal transit is a physiological response for regulating intestinal cholesterol absorption. The Cckar gene has been identified to be an important gallstone gene, Lith13, in inbred mice by a powerful quantitative trait locus analysis. Knockout of the Cckar gene in mice enhances cholesterol cholelithogenesis by impairing gallbladder contraction and emptying, promoting cholesterol crystallization and crystal growth, and increasing intestinal cholesterol absorption. Clinical and epidemiological studies have demonstrated that several variants in the CCKAR gene are associated with increased prevalence of cholesterol cholelithiasis in humans. Dysfunctional gallbladder emptying in response to exogenously administered CCK-8 is often found in patients with cholesterol gallstones, and patients with pigment gallstones display an intermediate degree of gallbladder motility defect. Gallbladder hypomotility is also revealed in some subjects without gallstones under several conditions: pregnancy, total parenteral nutrition, celiac disease, oral contraceptives and conjugated estrogens, obesity, diabetes, the metabolic syndrome, and administration of CCKAR antagonists. The physical-chemical, genetic, and molecular studies of Lith13 show that dysfunctional CCKAR enhances susceptibility to cholesterol gallstones through two primary mechanisms: impaired gallbladder emptying is a key risk factor for the development of gallbladder hypomotility, biliary sludge (the precursor of gallstones), and microlithiasis, as well as delayed small intestinal transit augments cholesterol absorption as a major source for the hepatic hypersecretion of biliary cholesterol and for the accumulation of excess cholesterol in the gallbladder wall that further worsens impaired gallbladder motor function. If these two defects in the gallbladder and small intestine could be prevented by the potent CCKAR agonists, the risk of developing cholesterol gallstones could be dramatically reduced.
Collapse
Affiliation(s)
- Helen H. Wang
- Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA;
| | - Piero Portincasa
- Department of Biomedical Sciences and Human Oncology, Clinica Medica “A. Murri”, University of Bari “Aldo Moro” Medical School, 70124 Bari, Italy;
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA; (M.L.); (P.T.)
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA; (M.L.); (P.T.)
| | - David Q.-H. Wang
- Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA;
| |
Collapse
|
5
|
DeLeon C, Wang HH, Gunn J, Wilhelm M, Cole A, Arnett S, Wang DQH, Arnatt CK. A novel GPER antagonist protects against the formation of estrogen-induced cholesterol gallstones in female mice. J Lipid Res 2020; 61:767-777. [PMID: 32127396 PMCID: PMC7193967 DOI: 10.1194/jlr.ra119000592] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/21/2020] [Indexed: 01/08/2023] Open
Abstract
Many clinical studies and epidemiological investigations have clearly demonstrated that women are twice as likely to develop cholesterol gallstones as men, and oral contraceptives and other estrogen therapies dramatically increase that risk. Further, animal studies have revealed that estrogen promotes cholesterol gallstone formation through the estrogen receptor (ER) α, but not ERβ, pathway. More importantly, some genetic and pathophysiological studies have found that G protein-coupled estrogen receptor (GPER) 1 is a new gallstone gene, Lith18, on chromosome 5 in mice and produces additional lithogenic actions, working independently of ERα, to markedly increase cholelithogenesis in female mice. Based on computational modeling of GPER, a novel series of GPER-selective antagonists were designed, synthesized, and subsequently assessed for their therapeutic effects via calcium mobilization, cAMP, and ERα and ERβ fluorescence polarization binding assays. From this series of compounds, one new compound, 2-cyclohexyl-4-isopropyl-N-(4-methoxybenzyl)aniline (CIMBA), exhibits superior antagonism and selectivity exclusively for GPER. Furthermore, CIMBA reduces the formation of 17β-estradiol-induced gallstones in a dose-dependent manner in ovariectomized mice fed a lithogenic diet for 8 weeks. At 32 μg/day/kg CIMBA, no gallstones are found, even in ovariectomized ERα (-/-) mice treated with 6 μg/day 17β-estradiol and fed the lithogenic diet for 8 weeks. In conclusion, CIMBA treatment protects against the formation of estrogen-induced cholesterol gallstones by inhibiting the GPER signaling pathway in female mice. CIMBA may thus be a new agent for effectively treating cholesterol gallstone disease in women.
Collapse
Affiliation(s)
- Chelsea DeLeon
- Department of ChemistrySaint Louis University, St. Louis, MO
| | - Helen H. Wang
- Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY
| | - Joseph Gunn
- Department of ChemistrySaint Louis University, St. Louis, MO
| | - McKenna Wilhelm
- Department of ChemistrySaint Louis University, St. Louis, MO
| | - Aidan Cole
- Department of ChemistrySaint Louis University, St. Louis, MO
| | - Stacy Arnett
- Center for World Health and Medicine,Saint Louis University, St. Louis, MO
| | - David Q-H. Wang
- Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY
| | | |
Collapse
|
6
|
Wang HH, Portincasa P, Wang DQH. Update on the Molecular Mechanisms Underlying the Effect of Cholecystokinin and Cholecystokinin-1 Receptor on the Formation of Cholesterol Gallstones. Curr Med Chem 2019. [PMID: 28625150 DOI: 10.2174/0929867324666170619104801] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cholecystokinin (CCK) is an important neuro-intestinal peptide hormone produced by the enteroendocrine I-cells in the upper part of small intestine. Protein- and fat-enriched food plays an important role in triggering CCK secretion from the intestine. Carbohydrates stimulate only small amounts of CCK release. The CCK-1 receptor (CCK-1R) is largely localized in the gallbladder, sphincter of Oddi, pancreas, small intestine, gastric mucosa, and pyloric sphincter, where it is responsible for CCK to regulate multiple digestive processes including gallbladder contraction, pancreatic secretion, small intestinal transit, and gastric emptying. Accumulated evidence clearly demonstrates that CCK regulates gallbladder and small intestinal motility through CCK-1R signaling cascade and the effect of CCK-1R on small intestinal transit is a physiological response for regulating intestinal cholesterol absorption. Disruption of the Cck or the Cck-1r gene in mice significantly increases the formation of cholesterol gallstones by disrupting gallbladder emptying and biliary cholesterol metabolism, as well as promoting intestinal absorption of cholesterol. Abnormalities in gallbladder motility function in response to exogenously administered CCK are found primarily in patients with cholesterol gallstones. Patients with pigment gallstones display an intermediate degree of gallbladder motility defect without gallbladder inflammation and enlarged fasting gallbladder. Dysfunctional gallbladder contractility has been found under several conditions such as pregnancy, obesity, diabetes, celiac disease, and total parenteral nutrition although gallstones are not observed. The gallbladder-specific CCK-1R-selective agonist may lead to an efficacious novel way for preventing gallstone formation by promoting gallbladder emptying, particularly for pregnant women and subjects with dysfunctional gallbladder motility function such as celiac patients, as well as patients with total parenteral nutrition.
Collapse
Affiliation(s)
- Helen H Wang
- Department of Medicine, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Piero Portincasa
- Department of Biomedical Sciences and Human Oncology, University of Bari Medical School, Bari, Italy
| | - David Q-H Wang
- Department of Medicine, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| |
Collapse
|
7
|
Zhang Y, Lickteig AJ, Csanaky IL, Klaassen CD. Activation of PPARα decreases bile acids in livers of female mice while maintaining bile flow and biliary bile acid excretion. Toxicol Appl Pharmacol 2017; 338:112-123. [PMID: 29175453 DOI: 10.1016/j.taap.2017.11.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 11/16/2017] [Accepted: 11/19/2017] [Indexed: 01/20/2023]
Abstract
Fibrates are hypolipidemic drugs that act as activators of peroxisome proliferator-activated receptor α (PPARα). In both humans and rodents, females were reported to be less responsive to fibrates than males. Previous studies on fibrates and PPARα usually involved male mice, but little has been done in females. The present study aimed to provide the first comprehensive analysis of the effects of clofibrate (CLOF) and PPARα on bile acid (BA) homeostasis in female mice. Study in WT male mice showed that a 4-day CLOF treatment increased liver weight, bile flow, and biliary BA excretion, but decreased total BAs in both serum and liver. In contrast, WT female mice were less susceptible to these CLOF-mediated responses observed in males. In WT female mice, CLOF decreased total BAs in the liver, but had little effect on the mRNAs of hepatic BA-related genes. Next, a comparative analysis between WT and PPARα-null female mice showed that lack of PPARα in female mice decreased total BAs in serum, but had little effect on total BAs in liver or bile. However, lack of PPARα in female mice increased mRNAs of BA synthetic enzymes (Cyp7a1, Cyp8b1, Cyp27a1, and Cyp7b1) and transporters (Ntcp, Oatp1a1, Oatp1b2, and Mrp3). Furthermore, the increase of Cyp7a1 in PPARα-null female mice was associated with an increase in liver Fxr-Shp-Lrh-1 signaling. In conclusion, female mice are resistant to CLOF-mediated effects on BA metabolism observed in males, which could be attributed to PPARα-mediated suppression in females on genes involved in BA synthesis and transport.
Collapse
Affiliation(s)
- Youcai Zhang
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, PR China.
| | - Andrew J Lickteig
- Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas 66160,USA
| | - Iván L Csanaky
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation, Division of Gastroenterology, Children's Mercy Hospital & Clinics, Kansas City, MO 64108; USA; Department of Pediatrics, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
| | - Curtis D Klaassen
- Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas 66160,USA.
| |
Collapse
|
8
|
Bertaggia E, Jensen KK, Castro-Perez J, Xu Y, Di Paolo G, Chan RB, Wang L, Haeusler RA. Cyp8b1 ablation prevents Western diet-induced weight gain and hepatic steatosis because of impaired fat absorption. Am J Physiol Endocrinol Metab 2017; 313:E121-E133. [PMID: 28377401 PMCID: PMC5582885 DOI: 10.1152/ajpendo.00409.2016] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 01/05/2023]
Abstract
Bile acids (BAs) are cholesterol derivatives that regulate lipid metabolism, through their dual abilities to promote lipid absorption and activate BA receptors. However, different BA species have varying abilities to perform these functions. Eliminating 12α-hydroxy BAs in mice via Cyp8b1 knockout causes low body weight and improved glucose tolerance. The goal of this study was to determine mechanisms of low body weight in Cyp8b1-/- mice. We challenged Cyp8b1-/- mice with a Western-type diet and assessed body weight and composition. We measured energy expenditure, fecal calories, and lipid absorption and performed lipidomic studies on feces and intestine. We investigated the requirement for dietary fat in the phenotype using a fat-free diet. Cyp8b1-/- mice were resistant to Western diet-induced body weight gain, hepatic steatosis, and insulin resistance. These changes were associated with increased fecal calories, due to malabsorption of hydrolyzed dietary triglycerides. This was reversed by treating the mice with taurocholic acid, the major 12α-hydroxylated BA species. The improvements in body weight and steatosis were normalized by feeding mice a fat-free diet. The effects of BA composition on intestinal lipid handling are important for whole body energy homeostasis. Thus modulating BA composition is a potential tool for obesity or diabetes therapy.
Collapse
Affiliation(s)
- Enrico Bertaggia
- Department of Pathology and Cell Biology, Columbia University, New York, New York
| | - Kristian K Jensen
- Diabetes Department, Merck Research Laboratories, Kenilworth, New Jersey; and
| | - Jose Castro-Perez
- Diabetes Department, Merck Research Laboratories, Kenilworth, New Jersey; and
| | - Yimeng Xu
- Department of Pathology and Cell Biology, Columbia University, New York, New York
| | - Gilbert Di Paolo
- Department of Pathology and Cell Biology, Columbia University, New York, New York
- Denali Therapeutics, Incorporated, South San Francisco, California
| | - Robin B Chan
- Department of Pathology and Cell Biology, Columbia University, New York, New York
| | - Liangsu Wang
- Diabetes Department, Merck Research Laboratories, Kenilworth, New Jersey; and
| | - Rebecca A Haeusler
- Department of Pathology and Cell Biology, Columbia University, New York, New York;
| |
Collapse
|
9
|
Ferrell JM, Boehme S, Li F, Chiang JYL. Cholesterol 7α-hydroxylase-deficient mice are protected from high-fat/high-cholesterol diet-induced metabolic disorders. J Lipid Res 2016; 57:1144-54. [PMID: 27146480 DOI: 10.1194/jlr.m064709] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Indexed: 12/31/2022] Open
Abstract
Cholesterol 7α-hydroxylase (CYP7A1) is the first and rate-limiting enzyme in the conversion of cholesterol to bile acids in the liver. In addition to absorption and digestion of nutrients, bile acids play a critical role in the regulation of lipid, glucose, and energy homeostasis. We have backcrossed Cyp7a1(-/-) mice in a mixed B6/129Sv genetic background to C57BL/6J mice to generate Cyp7a1(-/-) mice in a near-pure C57BL/6J background. These mice survive well and have normal growth and a bile acid pool size ∼60% of WT mice. The expression of the genes in the alternative bile acid synthesis pathway are upregulated, resulting in a more hydrophilic bile acid composition with reduced cholic acid (CA). Surprisingly, Cyp7a1(-/-) mice have improved glucose sensitivity with reduced liver triglycerides and fecal bile acid excretion, but increased fecal fatty acid excretion and respiratory exchange ratio (RER) when fed a high-fat/high-cholesterol diet. Supplementing chow and Western diets with CA restored bile acid composition, reversed the glucose tolerant phenotype, and reduced the RER. Our current study points to a critical role of bile acid composition, rather than bile acid pool size, in regulation of glucose, lipid, and energy metabolism to improve glucose and insulin tolerance, maintain metabolic homeostasis, and prevent high-fat diet-induced metabolic disorders.
Collapse
Affiliation(s)
- Jessica M Ferrell
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH
| | - Shannon Boehme
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH
| | - Feng Li
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX
| | - John Y L Chiang
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH
| |
Collapse
|
10
|
Shahid RA, Wang DQH, Fee BE, McCall SJ, Romac JMJ, Vigna SR, Liddle RA. Endogenous elevation of plasma cholecystokinin does not prevent gallstones. Eur J Clin Invest 2015; 45:237-46. [PMID: 25641074 PMCID: PMC4342269 DOI: 10.1111/eci.12400] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 01/05/2015] [Indexed: 12/28/2022]
Abstract
BACKGROUND Regular gall bladder contraction reduces bile stasis and prevents gallstone formation. Intraduodenal administration of exogenous pancreatic secretory trypsin inhibitor-I (PSTI-I, also known as monitor peptide) causes cholecystokinin (CCK) secretion. DESIGN We proposed that stimulation of CCK release by PSTI would produce gall bladder contraction and prevent gallstones in mice fed a lithogenic diet. Therefore, we tested the effect of overexpression of rat PSTI-I in pancreatic acinar cells on plasma CCK levels and gall bladder function in a transgenic mouse line (TgN[Psti1]; known hereafter as PSTI-I tg). RESULTS Importantly, PSTI tg mice had elevated fasting and fed plasma CCK levels compared to wild-type (WT) mice. Only mice fed the lithogenic diet developed gallstones. Both fasting and stimulated plasma CCK levels were substantially reduced in both WT and PSTI-I tg mice on the lithogenic diet. Moreover, despite higher CCK levels PSTI-I tg animals developed more gallstones than WT animals. CONCLUSIONS Together with the previously observed decrease in CCK-stimulated gall bladder emptying in mice fed a lithogenic diet, our findings suggest that a lithogenic diet causes gallstone formation by impaired CCK secretion in addition to reduced gall bladder sensitivity to CCK.
Collapse
Affiliation(s)
- Rafiq A Shahid
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | | | | | | | | | | | | |
Collapse
|
11
|
Abstract
Accumulation of triacylglycerols within the cytoplasm of hepatocytes to the degree that lipid droplets are visible microscopically is called liver steatosis. Most commonly, it occurs when there is an imbalance between the delivery or synthesis of fatty acids in the liver and their disposal through oxidative pathways or secretion into the blood as a component of triacylglycerols in very low density lipoprotein. This disorder is called nonalcoholic fatty liver disease (NAFLD) in the absence of alcoholic abuse and viral hepatitis, and it is often associated with insulin resistance, obesity and type 2 diabetes. Also, liver steatosis can be induced by many other causes including excessive alcohol consumption, infection with genotype 3 hepatitis C virus and certain medications. Whereas hepatic triacylglycerol accumulation was once considered the ultimate effector of hepatic lipotoxicity, triacylglycerols per se are quite inert and do not induce insulin resistance or cellular injury. Rather, lipotoxic injury in the liver appears to be mediated by the global ongoing fatty acid enrichment in the liver, paralleling the development of insulin resistance. A considerable number of fatty acid metabolites may be responsible for hepatic lipotoxicity and liver injury. Additional key contributors include hepatic cytosolic lipases and the "lipophagy" of lipid droplets, as sources of hepatic fatty acids. The specific origin of the lipids, mainly triacylglycerols, accumulating in liver has been unraveled by recent kinetic studies, and identifying the origin of the accumulated triacylglycerols in the liver of patients with NAFLD may direct the prevention and treatment of this condition.
Collapse
Affiliation(s)
- David Q-H Wang
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, Saint Louis University School of Medicine, St. Louis, Missouri
| | | | | |
Collapse
|
12
|
Pathak P, Li T, Chiang JYL. Retinoic acid-related orphan receptor α regulates diurnal rhythm and fasting induction of sterol 12α-hydroxylase in bile acid synthesis. J Biol Chem 2013; 288:37154-65. [PMID: 24226095 DOI: 10.1074/jbc.m113.485987] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Sterol 12α-hydroxylase (CYP8B1) is required for cholic acid synthesis and plays a critical role in intestinal cholesterol absorption and pathogenesis of cholesterol gallstone, dyslipidemia, and diabetes. In this study we investigated the underlying mechanism of fasting induction and circadian rhythm of CYP8B1 by a cholesterol-activated nuclear receptor and core clock gene retinoic acid-related orphan receptor α (RORα). Fasting stimulated, whereas restricted-feeding reduced expression of CYP8B1 mRNA and protein. However, fasting and feeding had little effect on the diurnal rhythm of RORα mRNA expression, but fasting increased RORα protein levels by cAMP-activated protein kinase A-mediated phosphorylation and stabilization of the protein. Adenovirus-mediated gene transduction of RORα to mice strongly induced CYP8B1 expression, and increased liver cholesterol and 12α-hydroxylated bile acids in the bile acid pool and serum. A reporter assay identified a functional RORα response element in the CYP8B1 promoter. RORα recruited cAMP response element-binding protein-binding protein (CBP) to stimulate histone acetylation on the CYP8B1 gene promoter. In conclusion, RORα is a key regulator of diurnal rhythm and fasting induction of CYP8B1, which regulates bile acid composition and serum and liver cholesterol levels. Antagonizing RORα activity may be a therapeutic strategy for treating inflammatory diseases such as non-alcoholic fatty liver disease and type 2 diabetes.
Collapse
Affiliation(s)
- Preeti Pathak
- From the Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio 44272 and
| | | | | |
Collapse
|
13
|
Wang TY, Liu M, Portincasa P, Wang DQH. New insights into the molecular mechanism of intestinal fatty acid absorption. Eur J Clin Invest 2013; 43:1203-23. [PMID: 24102389 PMCID: PMC3996833 DOI: 10.1111/eci.12161] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 08/20/2013] [Indexed: 01/05/2023]
Abstract
BACKGROUND Dietary fat is one of the most important energy sources of all the nutrients. Fatty acids, stored as triacylglycerols (also called triglycerides) in the body, are an important reservoir of stored energy and derived primarily from animal fats and vegetable oils. DESIGN Although the molecular mechanisms for the transport of water-insoluble amphipathic fatty acids across cell membranes have been debated for many years, it is now believed that the dominant means for intestinal fatty acid uptake is via membrane-associated fatty acid-binding proteins, that is, fatty acid transporters on the apical membrane of enterocytes. RESULTS These findings indicate that intestinal fatty acid absorption is a multistep process that is regulated by multiple genes at the enterocyte level, and intestinal fatty acid absorption efficiency could be determined by factors influencing intraluminal fatty acid molecules across the brush border membrane of enterocytes. To facilitate research on intestinal, hepatic and plasma triacylglycerol metabolism, it is imperative to establish standard protocols for precisely and accurately measuring the efficiency of intestinal fatty acid absorption in humans and animal models. In this review, we will discuss the chemical structure and nomenclature of fatty acids and summarize recent progress in investigating the molecular mechanisms underlying the intestinal absorption of fatty acids, with a particular emphasis on the physical chemistry of intestinal lipids and the molecular physiology of intestinal fatty acid transporters. CONCLUSIONS A better understanding of the molecular mechanism of intestinal fatty acid absorption should lead to novel approaches to the treatment and the prevention of fatty acid-related metabolic diseases that are prevalent worldwide.
Collapse
Affiliation(s)
- Tony Y Wang
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, MO, USA; Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | | | | | | |
Collapse
|
14
|
Wang HH, Portincasa P, de Bari O, Liu KJ, Garruti G, Neuschwander-Tetri BA, Wang DQH. Prevention of cholesterol gallstones by inhibiting hepatic biosynthesis and intestinal absorption of cholesterol. Eur J Clin Invest 2013; 43:413-26. [PMID: 23419155 PMCID: PMC3996849 DOI: 10.1111/eci.12058] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 01/22/2013] [Indexed: 12/14/2022]
Abstract
BACKGROUND Cholesterol cholelithiasis is a multifactorial disease influenced by a complex interaction of genetic and environmental factors and represents a failure of biliary cholesterol homoeostasis in which the physical-chemical balance of cholesterol solubility in bile is disturbed. DESIGN The primary pathophysiologic event is persistent hepatic hypersecretion of biliary cholesterol, which has both hepatic and small intestinal components. The majority of the environmental factors are probably related to Western-type dietary habits, including excess cholesterol consumption. RESULTS Laparoscopic cholecystectomy, one of the most commonly performed surgical procedures in the United States, is nowadays a major treatment for gallstones. However, it is invasive and can cause surgical complications, and not all patients with symptomatic gallstones are candidates for surgery. The hydrophilic bile acid, ursodeoxycholic acid (UDCA), has been employed as first-line pharmacological therapy in a subgroup of symptomatic patients with small, radiolucent cholesterol gallstones. Long-term administration of UDCA can promote the dissolution of cholesterol gallstones. However, the optimal use of UDCA is not always achieved in clinical practice because of failure to titrate the dose adequately. CONCLUSIONS Therefore, the development of novel, effective and noninvasive therapies is crucial for reducing the costs of health care associated with gallstones. In this review, we summarize recent progress in investigating the inhibitory effects of ezetimibe and statins on intestinal absorption and hepatic biosynthesis of cholesterol, respectively, for the treatment of gallstones, as well as in elucidating their molecular mechanisms by which combination therapy could prevent this very common liver disease worldwide.
Collapse
Affiliation(s)
- Helen H Wang
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | | | | | | | | | | | | |
Collapse
|
15
|
Inhibition of cholesterol absorption: targeting the intestine. Pharm Res 2012; 29:3235-50. [PMID: 22923351 DOI: 10.1007/s11095-012-0858-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 08/06/2012] [Indexed: 01/06/2023]
Abstract
Atherosclerosis, the gradual formation of a lipid-rich plaque in the arterial wall is the primary cause of Coronary Artery Disease (CAD), the leading cause of mortality worldwide. Hypercholesterolemia, elevated circulating cholesterol, was identified as a key risk factor for CAD in epidemiological studies. Since the approval of Mevacor in 1987, the primary therapeutic intervention for hypercholesterolemia has been statins, drugs that inhibit the biosynthesis of cholesterol. With improved understanding of the risks associated with elevated cholesterol levels, health agencies are recommending reductions in cholesterol that are not achievable in every patient with statins alone, underlying the need for improved combination therapies. The whole body cholesterol pool is derived from two sources, biosynthesis and diet. Although statins are effective at reducing the biosynthesis of cholesterol, they do not inhibit the absorption of cholesterol, making this an attractive target for adjunct therapies. This report summarizes the efforts to target the gastrointestinal absorption of cholesterol, with emphasis on specifically targeting the gastrointestinal tract to avoid the off-target effects sometimes associated with systemic exposure.
Collapse
|
16
|
Zhang Y, Breevoort SR, Angdisen J, Fu M, Schmidt DR, Holmstrom SR, Kliewer SA, Mangelsdorf DJ, Schulman IG. Liver LXRα expression is crucial for whole body cholesterol homeostasis and reverse cholesterol transport in mice. J Clin Invest 2012; 122:1688-99. [PMID: 22484817 DOI: 10.1172/jci59817] [Citation(s) in RCA: 154] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 02/22/2012] [Indexed: 12/15/2022] Open
Abstract
Liver X receptors (LXRα and LXRβ) are important regulators of cholesterol and lipid metabolism, and their activation has been shown to inhibit cardiovascular disease and reduce atherosclerosis in animal models. Small molecule agonists of LXR activity are therefore of great therapeutic interest. However, the finding that such agonists also promote hepatic lipogenesis has led to the idea that hepatic LXR activity is undesirable from a therapeutic perspective. To investigate whether this might be true, we performed gene targeting to selectively delete LXRα in hepatocytes. Liver-specific deletion of LXRα in mice substantially decreased reverse cholesterol transport, cholesterol catabolism, and cholesterol excretion, revealing the essential importance of hepatic LXRα for whole body cholesterol homeostasis. Additionally, in a pro-atherogenic background, liver-specific deletion of LXRα increased atherosclerosis, uncovering an important function for hepatic LXR activity in limiting cardiovascular disease. Nevertheless, synthetic LXR agonists still elicited anti-atherogenic activity in the absence of hepatic LXRα, indicating that the ability of agonists to reduce cardiovascular disease did not require an increase in cholesterol excretion. Furthermore, when non-atherogenic mice were treated with synthetic LXR agonists, liver-specific deletion of LXRα eliminated the detrimental effect of increased plasma triglycerides, while the beneficial effect of increased plasma HDL was unaltered. In sum, these observations suggest that therapeutic strategies that bypass the liver or limit the activation of hepatic LXRs should still be beneficial for the treatment of cardiovascular disease.
Collapse
Affiliation(s)
- Yuan Zhang
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Xie M, Kotecha VR, Andrade JDP, Fox JG, Carey MC. Augmented cholesterol absorption and sarcolemmal sterol enrichment slow small intestinal transit in mice, contributing to cholesterol cholelithogenesis. J Physiol 2012; 590:1811-24. [PMID: 22331417 DOI: 10.1113/jphysiol.2011.224717] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cholesterol gallstones are associated with slow intestinal transit in humans as well as in animal models, but the molecular mechanism is unknown. We investigated in C57L/J mice whether the components of a lithogenic diet (LD; 1.0% cholesterol, 0.5% cholic acid and 17% triglycerides), as well as distal intestinal infection with Helicobacter hepaticus, influence small intestinal transit time. By quantifying the distribution of 3H-sitostanol along the length of the small intestine following intraduodenal instillation,we observed that, in both sexes, the geometric centre (dimensionless) was retarded significantly (P <0.05) by LD but not slowed further by helicobacter infection (males, 9.4±0.5 (uninfected), 9.6±0.5 (infected) on LD compared with 12.5±0.4 and 11.4±0.5 on chow). The effect of the LD was reproduced only by the binary combination of cholesterol and cholic acid. We inferred that the LD-induced cholesterol enrichment of the sarcolemmae of intestinal smooth muscle cells produced hypomotility from signal-transduction decoupling of cholecystokinin (CCK), a physiological agonist for small intestinal propulsion in mice. Treatment with ezetimibe in an amount sufficient to block intestinal cholesterol absorption caused small intestinal transit time to return to normal. In most cholesterol gallstone-prone humans, lithogenic bile carries large quantities of hepatic cholesterol into the upper small intestine continuously, thereby reproducing this dietary effect in mice. Intestinal hypomotility promotes cholelithogenesis by augmenting formation of deoxycholate, a pro-lithogenic secondary bile salt, and increasing the fraction of intestinal cholesterol absorbed.
Collapse
Affiliation(s)
- Meimin Xie
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | | | | | | | | |
Collapse
|
18
|
Villablanca AC, Tenwolde A, Lee M, Huck M, Mumenthaler S, Rutledge JC. 17beta-estradiol prevents early-stage atherosclerosis in estrogen receptor-alpha deficient female mice. J Cardiovasc Transl Res 2009; 2:289-99. [PMID: 19654889 PMCID: PMC2719738 DOI: 10.1007/s12265-009-9103-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2009] [Accepted: 04/17/2009] [Indexed: 11/25/2022]
Abstract
Estrogen is atheroprotective and a high-affinity ligand for both known estrogen receptors, ERα and ERβ. However, the role of the ERα in early-stage atherosclerosis has not been directly investigated and is incompletely understood. ERα-deficient (ERα−/−) and wild-type (ERα+/+) female mice consuming an atherogenic diet were studied concurrent with estrogen replacement to distinguish the actions of 17β-estradiol (E2) from those of ERα on the development of early atherosclerotic lesions. Mice were ovariectomized and implanted with subcutaneous slow-release pellets designed to deliver 6 or 8 μg/day of exogenous 17β-estradiol (E2) for a period of up to 4 months. Ovariectomized mice (OVX) with placebo pellets (E2-deficient controls) were compared to mice with endogenous E2 (intact ovaries) and exogenous E2. Aortas were analyzed for lesion area, number, and distribution. Lipid and hormone levels were also determined. Compared to OVX, early lesion development was significantly (p < 0.001) attenuated by E2 with 55–64% reduction in lesion area by endogenous E2 and >90% reduction by exogenous E2. Compared to OVX, a decline in lesion number (2- to 4-fold) and lesser predilection (~4-fold) of lesion formation in the proximal aorta also occurred with E2. Lesion size, development, number, and distribution inversely correlated with circulating plasma E2 levels. However, atheroprotection was independent of ERα status, and E2 athero-protection in both genotypes was not explained by changes in plasma lipid levels (total cholesterol, triglyceride, and high-density lipoprotein cholesterol). The ERα is not essential for endogenous/exogenous E2-mediated protection against early-stage atherosclerosis. These observations have potentially significant implications for understanding the molecular and cellular mechanisms and timing of estrogen action in different estrogen receptor (ER) deletion murine models of atherosclerosis, as well as implications to human studies of ER polymorphisms and lipid metabolism. Our findings may contribute to future improved clinical decision-making concerning the use of hormone therapy.
Collapse
Affiliation(s)
- Amparo C Villablanca
- Department of Internal Medicine, University of California, Davis, Davis, CA, USA.
| | | | | | | | | | | |
Collapse
|
19
|
Xie Y, Newberry EP, Kennedy SM, Luo J, Davidson NO. Increased susceptibility to diet-induced gallstones in liver fatty acid binding protein knockout mice. J Lipid Res 2009; 50:977-87. [PMID: 19136665 DOI: 10.1194/jlr.m800645-jlr200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Quantitative trait mapping identified a locus colocalizing with L-Fabp, encoding liver fatty acid binding protein, as a positional candidate for murine gallstone susceptibility. When fed a lithogenic diet (LD) for 2 weeks, L-Fabp(-/-) mice became hypercholesterolemic with increased hepatic VLDL cholesterol secretion. Seventy-five percent of L-Fabp(-/-) mice developed solid gallstones compared with 6% of wild-type mice with an increased gallstone score (3.29 versus 0.62, respectively; P < 0.01). Hepatic free cholesterol content, biliary cholesterol secretion, and the cholesterol saturation index of hepatic bile were increased in LD-fed L-Fabp(-/-) mice. Chow-fed L-Fabp(-/-) mice demonstrated increased fecal bile acid (BA) excretion accompanied by decreased ileal Asbt expression. By contrast, there was an increased BA pool and decreased fecal BA excretion in LD-fed L-Fabp(-/-) mice, associated with increased proximal intestinal Asbt mRNA expression, suggesting that intestinal BA absorption was enhanced in LD-fed L-Fabp(-/-) mice. The increase in biliary BA secretion and enterohepatic pool size in LD-fed L-Fabp(-/-) mice was accompanied by downregulation of Cyp7a1 mRNA and increased intestinal mRNA abundance of Fgf-15, Fxr, and Fabp6. These findings suggest that changes in hepatic cholesterol metabolism and biliary lipid secretion as well as changes in enterohepatic BA metabolism increase gallstone susceptibility in LD fed L-Fabp(-/-) mice.
Collapse
Affiliation(s)
- Yan Xie
- Department of Medicine, Division of Gastroenterology, Washington University School of Medicine, St Louis, MO 63110, USA
| | | | | | | | | |
Collapse
|
20
|
Martini C, Pallottini V. Cholesterol: from feeding to gene regulation. GENES & NUTRITION 2007; 2:181-93. [PMID: 18850174 PMCID: PMC2474947 DOI: 10.1007/s12263-007-0049-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Accepted: 11/16/2006] [Indexed: 01/20/2023]
Abstract
We present here a brief description of the path that cholesterol covers from its intestinal absorption to its effects exerted on gene regulation. In particular, the relationship between cholesterol and the protein complexes involved in the intricate gene regulation mechanism implicated in cholesterol homeostasis will be discussed. In addition, a new target role for the pharmacological interventions of one of these factors, the insulin-induced gene (Insig) protein, will be introduced.
Collapse
Affiliation(s)
- C. Martini
- Department of Biology, University of Rome “Roma Tre”, Viale Marconi, 446, 00146 Rome, Italy
| | - V. Pallottini
- Department of Biology, University of Rome “Roma Tre”, Viale Marconi, 446, 00146 Rome, Italy
| |
Collapse
|
21
|
Venniyoor A. Cholesterol gallstones and cancer of gallbladder (CAGB): molecular links. Med Hypotheses 2007; 70:646-53. [PMID: 17855001 DOI: 10.1016/j.mehy.2007.06.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2007] [Accepted: 06/19/2007] [Indexed: 01/11/2023]
Abstract
There is a known association between cholesterol gallstones and cancer of gall bladder (CAGB). However, the exact relation is not clear. It is proposed they are linked at molecular level by the activity of the orphan nuclear receptors (ONRs) and ABC transporter pumps involved in cholesterol and xenobiotic efflux from the liver into bile. There is evidence that these two pathways are closely interlinked and influence each other. Genetic and environmental factors that upregulate these systems can lead to the simultaneous pumping of cholesterol (which precipitate as gallstones) and a food carcinogen into the bile in gall bladder; the latter causes malignant transformation. Aflatoxin B, a potent hepatocarcinogen, could be the culprit in endemic regions such as South America and North India.
Collapse
Affiliation(s)
- Ajit Venniyoor
- Department of Medicine and Medical Oncology, INHS Asvini, Near RC Church, Colaba, Mumbai Bombay, Maharastra 400 005, India.
| |
Collapse
|
22
|
Maurer KJ, Rogers AB, Ge Z, Wiese AJ, Carey MC, Fox JG. Helicobacter pylori and cholesterol gallstone formation in C57L/J mice: a prospective study. Am J Physiol Gastrointest Liver Physiol 2006; 290:G175-82. [PMID: 16109843 DOI: 10.1152/ajpgi.00272.2005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Recently, we demonstrated that cholesterol gallstone-prone C57L/J mice rarely develop gallstones unless they are infected with certain cholelithogenic enterohepatic Helicobacter species. Because the common gastric pathogen H. pylori has been identified in the hepatobiliary tree of cholesterol gallstone patients, we wanted to ascertain if H. pylori is cholelithogenic, by prospectively studying C57L infected mice fed a lithogenic diet. Weanling, Helicobacter spp.-free male C57L mice were either infected with H. pylori SS1 or sham dosed. Mice were then fed a lithogenic diet (1.0% cholesterol, 0.5% cholic acid, and 15% dairy triglycerides) for 8 wk. At 16 wk of age, mice were euthanatized, the biliary phenotype was analyzed microscopically, and tissues were analyzed histopathologically. H. pylori infection did not promote cholesterol monohydrate crystal formation (20% vs. 10%), sandy stone formation (0% for both), or true gallstone formation (20%) compared with uninfected mice fed the lithogenic diet (10%). Additionally, H. pylori failed to stimulate mucin gel accumulation in the gallbladder or alter gallbladder size compared with uninfected animals. H. pylori-infected C57L mice developed moderate to severe gastritis by 12 wk, and the lithogenic diet itself produced lesions in the forestomach, which were exacerbated by the infection. We conclude that H. pylori infection does not play any role in murine cholesterol gallstone formation. Nonetheless, the C57L mouse develops severe lesions of both the glandular and nonglandular stomach in response to H. pylori infection and the lithogenic diet, respectively.
Collapse
Affiliation(s)
- Kirk J Maurer
- Division of Comparative Medicine, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA.
| | | | | | | | | | | |
Collapse
|
23
|
Wang Y, Vanstone CA, Parsons WD, Jones PJH. Validation of a single-isotope-labeled cholesterol tracer approach for measuring human cholesterol absorption. Lipids 2004; 39:87-91. [PMID: 15055240 DOI: 10.1007/s11745-004-1206-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cholesterol absorption is frequently determined using the plasma dual stable-isotope ratio method (PDSIRM). However, this method involves intravenous injection of stable-isotope-labeled cholesterol with simultaneous oral administration of differently labeled cholesterol, which results in high study costs and involves additional ethical considerations. The objective of the present study was to validate a simpler single-isotope method for determining cholesterol absorption against PDSIRM by using data from two previous studies. Enrichments of carbon-13 (13C and deuterium in red blood cells were analyzed by using differential isotope ratio MS. The area under the curve of 13C-enrichment in the plasma free-cholesterol pool was found to be significantly correlated with cholesterol absorption measured by using PDSIRM for study 1 (r = 0.85, P < 0.0001) and study 2 (r = 0.81, P < 0.0001). Average 13C-enrichment correlated with the area under the curve of 13C-enrichment in the plasma free cholesterol for both study 1 (r = 0.98, P < 0.0001) and study 2 (r = 1.00, P < 0.0001). Study 1 examined the efficacy and mechanisms of unesterified plant sterols and stanols on lipid profiles in hypercholesterolemic men and women, while study 2 investigated the effects of phytosterol vs. phytostanol esters on plasma lipid levels and cholesterol kinetics in hyperlipidemic men. Experimental approaches to determine cholesterol absorption were identical between the two studies. Consequently, in both studies, correlations (r = 0.88, P < 0.0001 for study 1, and r = 0.82, P < 0.0001 for study 2) were found between the average 13C-enrichment of plasma free cholesterol and cholesterol absorption measured by PDSIRM. These results suggest that a single-isotope-labeled cholesterol tracer approach can be used as a reliable noninvasive method to replace PDSIRM for examining changes in cholesterol absorption.
Collapse
Affiliation(s)
- Yanwen Wang
- School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada, H9X 3V9
| | | | | | | |
Collapse
|
24
|
Wang DQH, Schmitz F, Kopin AS, Carey MC. Targeted disruption of the murine cholecystokinin-1 receptor promotes intestinal cholesterol absorption and susceptibility to cholesterol cholelithiasis. J Clin Invest 2004; 114:521-8. [PMID: 15314689 PMCID: PMC503765 DOI: 10.1172/jci16801] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2002] [Accepted: 06/29/2004] [Indexed: 01/09/2023] Open
Abstract
Cholecystokinin (CCK) modulates contractility of the gallbladder, the sphincter of Oddi, and the stomach. These effects are mediated through activation of gastrointestinal smooth muscle as well as enteric neuron CCK-1 receptors (CCK-1Rs). To investigate the potential physiological and pathophysiological functions linked to CCK-1R-mediated signaling, we compared male WT and CCK-1R-deficient mice (129/SvEv). After 12 weeks on either a standard mouse chow or a lithogenic diet (containing 1% cholesterol, 0.5% cholic acid, and 15% dairy fat), small-intestinal transit time, intestinal cholesterol absorption, biliary cholesterol secretion, and cholesterol gallstone prevalence were compared in knockout versus WT animals. Analysis of mice on either the chow or the lithogenic diet revealed that CCK-1R(-/-) animals had larger gallbladder volumes (predisposing to bile stasis), significant retardation of small-intestinal transit times (resulting in increased cholesterol absorption), and increased biliary cholesterol secretion rates. The elevation in bile cholesterol, coupled with a tendency toward gallbladder stasis (due to the absence of CCK-induced contraction), facilitates nucleation, growth, and agglomeration of cholesterol monohydrate crystals; this sequence of events in turn results in a significantly higher prevalence of cholesterol gallstones in the CCK-1R-null mice.
Collapse
Affiliation(s)
- David Q-H Wang
- Department of Medicine, Liver Center and Gastroenterology Division, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | | | | | | |
Collapse
|
25
|
Wang HH, Afdhal NH, Gendler SJ, Wang DQH. Lack of the intestinal Muc1 mucin impairs cholesterol uptake and absorption but not fatty acid uptake in Muc1-/- mice. Am J Physiol Gastrointest Liver Physiol 2004; 287:G547-54. [PMID: 15075252 DOI: 10.1152/ajpgi.00097.2004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Before cholesterol and fatty acid molecules in the small intestinal lumen can interact with their possible transporters for uptake and absorption, they must pass through a diffusion barrier, which may modify the kinetics of nutrient assimilation. This barrier includes an unstirred water layer and a surface mucous coat, which is located at the intestinal lumen-membrane interface. In the present study, we investigated whether disruption of the mucin gene (Muc)1 may influence intestinal uptake and absorption of cholesterol and fatty acid in male Muc1(-/-) mice. The wild-type mice displayed relatively high levels of Muc1, Muc2, Muc3, and Muc4 mRNAs and relatively low levels of Muc5ac and Muc5b mRNAs in the small intestine. The absence of Muc1 mRNA and protein in the small intestines of Muc1(-/-) mice confirmed complete knockout of the Muc1 gene, but the mRNA expression for other mucin genes remained unchanged. Intestinal uptake and absorption of cholesterol but not palmitic acid were significantly reduced in Muc1(-/-) mice compared with the wild-type mice. However, knockout of the Muc1 gene did not impair either expression levels of the genes that encode intestinal sterol efflux transporters Abcg5 and Abcg8 and fatty acid transporter Fatp4 or small intestinal transit rates. We conclude that physiological levels of the epithelial mucin produced by the Muc1 gene are necessary for normal intestinal uptake and absorption of cholesterol in mice. Our study implies that because cholesterol absorption efficiency is reduced by approximately 50% in Muc1-deficient mice, there may be one or more additional pathways for cholesterol absorption.
Collapse
Affiliation(s)
- Helen H Wang
- Department of Medicine, Liver Center and Gastroenterology Division, Beth Israel Deaconess Medical Center, Harvard Medical School and Harvard Digestive Diseases Center, Boston, Massachusetts 02215, USA
| | | | | | | |
Collapse
|
26
|
Lyons MA, Korstanje R, Li R, Walsh KA, Churchill GA, Carey MC, Paigen B. Genetic contributors to lipoprotein cholesterol levels in an intercross of 129S1/SvImJ and RIIIS/J inbred mice. Physiol Genomics 2004; 17:114-21. [PMID: 14872007 DOI: 10.1152/physiolgenomics.00168.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To determine the genetic contribution to variation among lipoprotein cholesterol levels, we performed quantitative trait locus (QTL) analyses on an intercross between mouse strains RIIIS/J and 129S1/SvImJ. Male mice of the parental strains and the reciprocal F1and F2populations were fed a high-cholesterol, cholic acid-containing diet for 8–12 wk. At the end of the feeding period, plasma total, high-density lipoprotein (HDL), and non-HDL cholesterol were determined. For HDL cholesterol, we identified three significant QTLs on chromosomes (Chrs) 1 ( D1Mit507, 88 cM, 72–105 cM, 4.8 LOD), 9 ( D11Mit149, 14 cM, 10–25 cM, 9.4 LOD), and 12 ( D12Mit60, 20 cM, 0–50 cM, 5.0 LOD). These QTLs were considered identical to QTLs previously named Hdlq5, Hdlq17, and Hdlq18, respectively, in crosses sharing strain 129. For total cholesterol, we identified two significant QTLs on Chrs 1 and 9, which were named Chol10 ( D1Mit507, 88 cM, 10–105 cM, 3.9 LOD) and Chol11 ( D11Mit149, 14 cM, 0–30 cM, 4.4 LOD), respectively. In addition, for total cholesterol, we identified two suggestive QTLs on Chrs 12 (distal) and 17, which remain unnamed. For non-HDL cholesterol, we identified and named one new QTL on Chr 17, Nhdlq3 ( D17Mit221, 58 cM, 45–60 cM, 3.4 LOD). Nhdlq3 colocalized with orthologous human QTLs for lipoprotein phenotypes, and with Abcg5 and Abcg8. Overall, we detected eight QTLs for lipoprotein cholesterol concentrations on Chrs 1, 9, 12, and 17 (each two per chromosome), including a new QTL for non-HDL cholesterol, Nhdlq3, on Chr 17.
Collapse
|
27
|
Wang DQH, Afdhal NH. Genetic analysis of cholesterol gallstone formation: searching for Lith (gallstone) genes. Curr Gastroenterol Rep 2004; 6:140-50. [PMID: 15191694 DOI: 10.1007/s11894-004-0042-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The genetics of cholesterol cholelithiasis is complex because a number of interacting genes regulate biliary cholesterol homeostasis. Quantitative trait locus (QTL) analysis is a powerful method for identifying primary rate-limiting genetic defects and discriminating them from secondary downstream lithogenic effects caused by mutations of the primary genes. The subsequent positional cloning of such genes responsible for QTLs may lead to the discovery of pathophysiologic functions of Lith (gallstone) genes. In this review, we present a map of candidate genes for Lith genes that may determine gallstone susceptibility in mice. The physical-chemical, pathophysiologic, and genetic studies of Lith genes in bile, liver, gallbladder, and intestine will be crucial for elucidating the genetic mechanisms of cholesterol gallstone disease in mice and in humans. Because exceptionally close homology exists between mouse and human genomes, the orthologous human LITH genes can often be recognized after mouse genes are identified.
Collapse
Affiliation(s)
- David Q-H Wang
- Liver Center, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, DA 601, Boston, MA 02215, USA
| | | |
Collapse
|
28
|
Wang DQH, Tazuma S, Cohen DE, Carey MC. Feeding natural hydrophilic bile acids inhibits intestinal cholesterol absorption: studies in the gallstone-susceptible mouse. Am J Physiol Gastrointest Liver Physiol 2003; 285:G494-502. [PMID: 12748061 DOI: 10.1152/ajpgi.00156.2003] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We explored the influence of the hydrophilic-hydrophobic balance of a series of natural bile acids on cholesterol absorption in the mouse. Male C57L/J mice were fed standard chow or chow supplemented with 0.5% cholic; chenodeoxycholic; deoxycholic; dehydrocholic; hyocholic; hyodeoxycholic; alpha-, beta-, or omega-muricholic; ursocholic; or ursodeoxycholic acids for 7 days. Biliary bile salts were measured by reverse-phase HPLC, and hydrophobicity indices were estimated by Heuman's method. Cholesterol absorption efficiency was determined by a plasma dual-isotope ratio method. In mice fed chow, natural proportions of tauro-beta-muricholate (42 +/- 6%) and taurocholate (50 +/- 7%) with a hydrophobicity index of -0.35 +/- 0.04 produced cholesterol absorption of 37 +/- 5%. Because bacterial and especially hepatic biotransformations of specific bile acids occurred, hydrophobicity indices of the resultant bile salt pools differed from fed bile acids. We observed a significant positive correlation between hydrophobicity indices of the bile salt pool and percent cholesterol absorption. The principal mechanism whereby hydrophilic bile acids inhibit cholesterol absorption appears to be diminution of intraluminal micellar cholesterol solubilization. Gene expression of intestinal sterol efflux transporters Abcg5 and Abcg8 was upregulated by feeding cholic acid but not by hydrophilic beta-muricholic acid nor by hydrophobic deoxycholic acid. We conclude that the hydrophobicity of the bile salt pool predicts the effects of individual fed bile acids on intestinal cholesterol absorption. Natural alpha- and beta-muricholic acids are the most powerful inhibitors of cholesterol absorption in mice and might act as potent cholesterol-lowering agents for prevention of cholesterol deposition diseases in humans.
Collapse
Affiliation(s)
- David Q-H Wang
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
| | | | | | | |
Collapse
|
29
|
Wittenburg H, Carey MC. Biliary cholesterol secretion by the twinned sterol half-transporters ABCG5 and ABCG8. J Clin Invest 2002; 110:605-9. [PMID: 12208859 PMCID: PMC151117 DOI: 10.1172/jci16548] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Henning Wittenburg
- Department of Medicine, Harvard Medical School, Gastroenterology Division, Brigham and Women's Hospital, and Harvard Digestive Diseases Center, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
30
|
Repa JJ, Mangelsdorf DJ. The role of orphan nuclear receptors in the regulation of cholesterol homeostasis. Annu Rev Cell Dev Biol 2001; 16:459-81. [PMID: 11031244 DOI: 10.1146/annurev.cellbio.16.1.459] [Citation(s) in RCA: 558] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cholesterol balance is maintained by a series of regulatory pathways that control the acquisition of cholesterol from endogenous and exogenous sources and the elimination of cholesterol, facilitated by its conversion to bile acids. Over the past decade, investigators have discovered that a family of membrane-bound transcription factors, sterol regulatory element-binding proteins (SREBPs), mediate the end-product repression of key enzymes of cholesterol biosynthesis. Recently orphan members of another family of transcription factors, the nuclear hormone receptors, have been found to regulate key pathways in bile acid metabolism, thereby controlling cholesterol elimination. The study of these orphan nuclear receptors suggests their potential as targets for new drug therapies.
Collapse
Affiliation(s)
- J J Repa
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9050, USA
| | | |
Collapse
|