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Peiris M, Aktar R, Reed D, Cibert-Goton V, Zdanaviciene A, Halder W, Robinow A, Corke S, Dogra H, Knowles CH, Blackshaw A. Decoy bypass for appetite suppression in obese adults: role of synergistic nutrient sensing receptors GPR84 and FFAR4 on colonic endocrine cells. Gut 2022; 71:928-937. [PMID: 34083384 PMCID: PMC8995825 DOI: 10.1136/gutjnl-2020-323219] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 05/09/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Colonic enteroendocrine cells (EECs) store and release potent anorectic hormones that are key regulators of satiety. EECs express multiple nutrient sensing receptors, particularly for medium-chain fatty acids (MCFAs): GPR84 and FFAR4. Here we show a non-surgical approach with targeted colonic delivery of MCFA, which induces EEC and neuronal activation leading to anorectic effects. DESIGN A randomised, double-blind, placebo-controlled, cross-over study was performed in obese adults given combined GPR84 and FFAR4 agonists in colonic release capsules before meals. We measured serum hormones, energy intake and appetite perception. Cell type, activation by agonists and hormone/serotonin release were determined in human colonic explants. Mouse colonic afferent nerve responses to nutrients/mediators were recorded electrophysiologically. RESULTS Subjects receiving GPR84 and FFAR4 agonists had reduced overall calorific intake and increased postprandial levels of PYY versus placebo. Receptors including GPR84 and FFAR4 were coexpressed on human colonic EEC. Activation of GPR84 exclusively induced intracellular pERK, whereas FFAR4 selectively activated pCaMKII. Coactivation of GPR84 and FFAR4 induced both phosphoproteins, and superadditive release of GLP-1 and PYY. Nutrients and hormones convergently activated murine colonic afterent nerves via GLP-1, Y2 and 5-HT3 receptors. CONCLUSIONS Colonic GPR84 and FFAR4 agonists reduce energy intake and increase postprandial PYY in obese adults. Human colonic EECs coexpress these receptors, which activate cells via parallel intracellular pathways and synergistically evoke hormone release. Further synergism occurs in sensory nerve responses to MCFA and EEC mediators. Thus, synergistic activation of colonic endocrine cells via nutrient receptors is an important target for metabolic regulation. TRAIL REGISTRATION NUMBER NCT04292236.
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Affiliation(s)
- Madusha Peiris
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Rubina Aktar
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - David Reed
- Gastrointestinal Diseases Research, Queen's University, Kingston, Queensland, Canada
| | - Vincent Cibert-Goton
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Ausra Zdanaviciene
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Writaja Halder
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Adam Robinow
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Simon Corke
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Harween Dogra
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Charles H Knowles
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Ashley Blackshaw
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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McCauley HA. Enteroendocrine Regulation of Nutrient Absorption. J Nutr 2020; 150:10-21. [PMID: 31504661 DOI: 10.1093/jn/nxz191] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/19/2019] [Accepted: 07/23/2019] [Indexed: 12/14/2022] Open
Abstract
Enteroendocrine cells (EECs) in the intestine regulate many aspects of whole-body physiology and metabolism. EECs sense luminal and circulating nutrients and respond by secreting hormones that act on multiple organs and organ systems, such as the brain, gallbladder, and pancreas, to control satiety, digestion, and glucose homeostasis. In addition, EECs act locally, on enteric neurons, endothelial cells, and the gastrointestinal epithelium, to facilitate digestion and absorption of nutrients. Many recent reports raise the possibility that EECs and the enteric nervous system may coordinate to regulate gastrointestinal functions. Loss of all EECs results in chronic malabsorptive diarrhea, placing EECs in a central role regulating nutrient absorption in the gut. Because there is increasing evidence that EECs can directly modulate the efficiency of nutrient absorption, it is possible that EECs are master regulators of a feed-forward loop connecting appetite, digestion, metabolism, and abnormally augmented nutrient absorption that perpetuates metabolic disease. This review focuses on the roles that specific EEC hormones play on glucose, peptide, and lipid absorption within the intestine.
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Affiliation(s)
- Heather A McCauley
- Division of Developmental Biology and the Center for Stem Cell and Organoid Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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3
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Abstract
Enteroendocrine cells (EECs) are sensory cells of the gastrointestinal tract. Most EECs reside in the mucosal lining of the stomach or intestine and sense food in the gut lumen. Food signals stimulate the release of hormones into the paracellular space where they either act locally or are taken up into the blood and circulate to distant organs. It recently was recognized that many EECs possess basal processes known as neuropods that not only contain hormones but also connect to nerves. This review describes how neuropods contribute to EEC function beyond typical hormonal actions. For example, gastrointestinal hormones not only act on distant organs, but, through neuropods, some act locally to stimulate other mucosal cells such as intestinal stem cells, enterocytes, or other EECs. With the recent discovery that EECs communicate directly with enteric nerves, EECs not only have the ability to sense food and bacteria in the gastrointestinal tract, but can communicate these signals directly to the nervous system.
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Abstract
Even the simplest animals possess sophisticated systems for sensing and securing nutrients. After all, ensuring adequate nutrition is essential for sustaining life. Once multicellular animals grew too large to be nourished by simple diffusion of nutrients from their environment, they required a digestive system for the absorption and digestion of food. The majority of cells in the digestive tract are enterocytes that are designed to absorb nutrients. However, the digestive tracts of animals ranging from worms to humans contain specialized cells that discriminate between nutrients and nondigestible ingestants. These cells "sense" both the environment within the gut lumen and nutrients as they cross the gut epithelium. This dual sensing is then translated into local signals that regulate the gut epithelium or distant signals through hormones or nerves. This review will discuss how sensors of the gut interact with cells of the epithelium and neurons to regulate epithelial integrity and initiate neural transmission from the gut lumen. © 2017 American Physiological Society. Compr Physiol 8:1019-1030, 2018.
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Affiliation(s)
- Rodger A Liddle
- Department of Medicine, Duke University and Durham VA Healthcare System, Durham, North Carolina, USA
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The melanocortin-4 receptor is expressed in enteroendocrine L cells and regulates the release of peptide YY and glucagon-like peptide 1 in vivo. Cell Metab 2014; 20:1018-29. [PMID: 25453189 PMCID: PMC4255280 DOI: 10.1016/j.cmet.2014.10.004] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 08/15/2014] [Accepted: 10/10/2014] [Indexed: 02/07/2023]
Abstract
The melanocortin-4 receptor (MC4R) is expressed in the brainstem and vagal afferent nerves and regulates a number of aspects of gastrointestinal function. Here we show that the receptor is also diffusely expressed in cells of the gastrointestinal system, from stomach to descending colon. Furthermore, MC4R is the second most highly enriched GPCR in peptide YY (PYY) and glucagon-like peptide 1 (GLP-1) expressing enteroendocrine L cells. When vectorial ion transport is measured across mouse or human intestinal mucosa, administration of α-MSH induces a MC4R-specific PYY-dependent antisecretory response consistent with a role for the MC4R in paracrine inhibition of electrolyte secretion. Finally, MC4R-dependent acute PYY and GLP-1 release from L cells can be stimulated in vivo by intraperitoneal (i.p.) administration of melanocortin peptides to mice. This suggests physiological significance for MC4R in L cells and indicates a previously unrecognized peripheral role for the MC4R, complementing vagal and central receptor functions.
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6
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Persaud SJ, Bewick GA. Peptide YY: more than just an appetite regulator. Diabetologia 2014; 57:1762-9. [PMID: 24917132 DOI: 10.1007/s00125-014-3292-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 05/08/2014] [Indexed: 12/13/2022]
Abstract
Replenishment of beta cell mass is a key aim of novel therapeutic interventions for diabetes, and the implementation of new strategies will be aided by understanding the mechanisms employed to regulate beta cell mass under normal physiological conditions. We have recently identified a new role for the gut hormone peptide YY (PYY) and the neuropeptide Y (NPY) receptor systems in the control of beta cell survival. PYY is perhaps best known for its role in regulating appetite and body weight, but its production by islet cells, the presence of NPY receptors on islets and the demonstration that Y1 activation causes proliferation of beta cells and protects them from apoptosis, suggest a role for this peptide in modulating beta cell mass. This review introduces PYY and its potential role in glucose homeostasis, then focuses on evidence supporting the concept that PYY and NPY receptors are exciting new targets for the preservation of beta cells.
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Affiliation(s)
- Shanta J Persaud
- Division of Diabetes & Nutritional Sciences, King's College London, Guy's Campus, London, SE1 1UL, UK
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Tough IR, Forbes S, Tolhurst R, Ellis M, Herzog H, Bornstein JC, Cox HM. Endogenous peptide YY and neuropeptide Y inhibit colonic ion transport, contractility and transit differentially via Y₁ and Y₂ receptors. Br J Pharmacol 2012; 164:471-84. [PMID: 21457230 DOI: 10.1111/j.1476-5381.2011.01401.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Peptide YY (PYY) and neuropeptide Y (NPY) activate Y receptors, targets under consideration as treatments for diarrhoea and other intestinal disorders. We investigated the gastrointestinal consequences of selective PYY or NPY ablation on mucosal ion transport, smooth muscle activity and transit using wild-type, single and double peptide knockout mice, comparing mucosal responses with those from human colon. EXPERIMENTAL APPROACH Mucosae were pretreated with a Y₁ (BIBO3304) or Y₂ (BIIE0246) receptor antagonist and changes in short-circuit current recorded. Colonic transit and colonic migrating motor complexes (CMMCs) were assessed in vitro and upper gastrointestinal and colonic transit measured in vivo. KEY RESULTS Y receptor antagonists revealed tonic Y₁ and Y₂ receptor-mediated antisecretory effects in human and wild-type mouse colon mucosae. In both, Y₁ tone was epithelial while Y₂ tone was neuronal. Y₁ tone was reduced 90% in PYY⁻/⁻ mucosa but unchanged in NPY⁻/⁻ tissue. Y₂ tone was partially reduced in NPY⁻/⁻ or PYY⁻/⁻ mucosae and abolished in tetrodotoxin-pretreated PYY⁻/⁻ tissue. Y₁ and Y₂ tone were absent in NPYPYY⁻/⁻ tissue. Colonic transit was inhibited by Y₁ blockade and increased by Y₂ antagonism indicating tonic Y₁ excitation and Y₂ inhibition respectively. Upper GI transit was increased in PYY⁻/⁻ mice only. Y₂ blockade reduced CMMC frequency in isolated mouse colon. CONCLUSIONS AND IMPLICATIONS Endogenous PYY and NPY induced significant mucosal antisecretory tone mediated by Y₁ and Y₂ receptors, via similar mechanisms in human and mouse colon mucosa. Both peptides contributed to tonic Y₂-receptor-mediated inhibition of colonic transit in vitro but only PYY attenuated upper GI transit.
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Affiliation(s)
- I R Tough
- King's College London, Wolfson Centre for Age-Related Diseases, Guy's Campus, London, UK
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Bohórquez DV, Liddle RA. Axon-like basal processes in enteroendocrine cells: characteristics and potential targets. Clin Transl Sci 2012; 4:387-91. [PMID: 22029814 DOI: 10.1111/j.1752-8062.2011.00299.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Enteroendocrine cells (EECs) play a key role in nutrient digestion and absorption, and are essential for normal life. Recently, EEC function has received considerable attention because several gastrointestinal hormones modulate insulin secretion and food intake; and, gut hormone-based therapies have been developed to treat diabetes mellitus. Despite these advances, the regulation of EECs remains poorly understood. The development of transgenic mouse models that express green fluorescent proteins (GFP) under specific hormone promoters (e.g., peptide YY-GFP) is shedding light onto previously overlooked features of EECs. These cells have prominent cytoplasmic processes that extend underneath enterocytes, and in some EECs, such as the L cell of the distal ileum, the basal process can be over 50 μm long. These basal cytoplasmic processes resemble axons and end in synaptic-like bouton. The location and anatomy of these processes suggest two functions: (1) to monitor absorbed nutrients at the base of enterocytes; and (2) to convey electrochemical information through cell-cell connections with subepithelial myofibroblasts and/or nerves located directly beneath in the lamina propria. Understanding how EECs communicate with cells in the lamina propria may provide novel ways to treat metabolic disorders such as obesity and diabetes.
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Affiliation(s)
- Diego V Bohórquez
- Department of Medicine, Duke University and Veterans Affairs Medical Center, Durham, North Carolina, USA
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Bohórquez DV, Chandra R, Samsa LA, Vigna SR, Liddle RA. Characterization of basal pseudopod-like processes in ileal and colonic PYY cells. J Mol Histol 2011; 42:3-13. [PMID: 21061049 DOI: 10.1007/s10735-010-9302-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 10/19/2010] [Indexed: 12/15/2022]
Abstract
The peptide tyrosine tyrosine (PYY) is produced and secreted from L cells of the gastrointestinal mucosa. To study the anatomy and function of PYY-secreting L cells, we developed a transgenic PYY-green fluorescent protein mouse model. PYY-containing cells exhibited green fluorescence under UV light and were immunoreactive to antibodies against PYY and GLP-1 (glucagon-like peptide-1, an incretin hormone also secreted by L cells). PYY-GFP cells from 15 μm thick sections were imaged using confocal laser scanning microscopy and three-dimensionally (3D) reconstructed. Results revealed unique details of the anatomical differences between ileal and colonic PYY-GFP cells. In ileal villi, the apical portion of PYY cells makes minimal contact with the lumen of the gut. Long pseudopod-like basal processes extend from these cells and form an interface between the mucosal epithelium and the lamina propria. Some basal processes are up to 50 μm in length. Multiple processes can be seen protruding from one cell and these often have a terminus resembling a synapse that appears to interact with neighboring cells. In colonic crypts, PYY-GFP cells adopt a spindle-like shape and weave in between epithelial cells, while maintaining contact with the lumen and lamina propria. In both tissues, cytoplasmic granules containing the hormones PYY and GLP-1 are confined to the base of the cell, often filling the basal process. The anatomical arrangement of these structures suggests a dual function as a dock for receptors to survey absorbed nutrients and as a launching platform for hormone secretion in a paracrine fashion.
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Cox HM, Tough IR, Woolston AM, Zhang L, Nguyen AD, Sainsbury A, Herzog H. Peptide YY is critical for acylethanolamine receptor Gpr119-induced activation of gastrointestinal mucosal responses. Cell Metab 2010; 11:532-42. [PMID: 20519124 PMCID: PMC2890049 DOI: 10.1016/j.cmet.2010.04.014] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 02/28/2010] [Accepted: 04/16/2010] [Indexed: 01/25/2023]
Abstract
Peptide YY (PYY) is released following food intake and regulates intestinal function and glucose homeostasis, but the mechanisms underpinning these processes are unclear. Enteroendocrine L cells contain PYY and express the acylethanolamine receptor, Gpr119. Here, we show that Gpr119 activation inhibited epithelial electrolyte secretion in human and mouse colon in a glucose-sensitive manner. Endogenous PYY selectively mediated these effects, since PYY(-/-) mice showed no Gpr119 response, but responses were observed in NPY(-/-) mice. Importantly, Gpr119 responses in wild-type (WT) mouse tissue and human colon were abolished by Y(1) receptor antagonism, but were not enhanced by dipeptidylpeptidase IV blockade, indicating that PYY processing to PYY(3-36) was not important. In addition, Gpr119 agonism reduced glycemic excursions after oral glucose delivery to WT mice but not PYY(-/-) mice. Taken together, these data demonstrate a previously unrecognized role of PYY in mediating intestinal Gpr119 activity and an associated function in controlling glucose tolerance.
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Affiliation(s)
- Helen M Cox
- King's College London, Wolfson Centre for Age-Related Diseases, Guy's Campus, London SE1 1UL, UK.
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11
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Zhang J, Halm ST, Halm DR. Adrenergic activation of electrogenic K+ secretion in guinea pig distal colonic epithelium: desensitization via the Y2-neuropeptide receptor. Am J Physiol Gastrointest Liver Physiol 2009; 297:G278-91. [PMID: 19497958 PMCID: PMC2724082 DOI: 10.1152/ajpgi.00077.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Adrenergic activation of electrogenic K+ secretion in isolated mucosa from guinea pig distal colon was desensitized by peptide-YY (PYY). Addition of PYY or neuropeptide-Y (NPY) to the bathing solution of mucosae in Ussing chambers suppressed the short-circuit current (Isc) corresponding to electrogenic Cl- secretion, whether stimulated by epinephrine (epi), prostaglandin-E2 (PGE2), or carbachol (CCh). Neither peptide markedly inhibited the large transient component of synergistic secretion (PGE2 + CCh). Sustained Cl- secretory Isc was inhibited approximately 65% by PYY or NPY, with IC50s of 4.1 +/- 0.9 nM and 9.4 +/- 3.8 nM, respectively. This inhibition was eliminated by BIIE0246, an antagonist of the Y2-neuropeptide receptor (Y2-NpR), but not by Y1-NpR antagonist BVD10. Adrenergic sensitivity for activation of K+ secretion in the presence of Y2-NpR blockade by BIIE0246 was (EC50s) 2.9 +/- 1.2 nM for epi and 13.3 +/- 1.0 nM for norepinephrine, approximately fourfold greater than in the presence of PYY. Expression of mRNA for both Y1-NpR and Y2-NpR was indicated by RT-PCR of RNA from colonic mucosa, and protein expression was indicated by immunoblot. Immunoreactivity (ir) for Y1-NpR and Y2-NpR was distinct in basolateral membranes of columnar epithelial cells in the crypts of Lieberkühn as well as intercrypt surface epithelium. Adrenergic nerves in proximity with crypts were detected by ir for dopamine-beta-hydroxylase, and a portion of these nerves also contained NPY(ir). BIIE0246 addition increased secretagog-activated Isc, consistent with in vitro release of either PYY or NPY. Thus PYY and NPY were able to suppress Cl- secretory capacity and desensitize the adrenergic K+ secretory response, providing a direct inhibitory counterbalance against secretory activation.
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Affiliation(s)
- Jin Zhang
- Department of Neuroscience, Cell Biology and Physiology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
| | - Susan T. Halm
- Department of Neuroscience, Cell Biology and Physiology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
| | - Dan R. Halm
- Department of Neuroscience, Cell Biology and Physiology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
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El Karim IA, Lamey PJ, Linden GJ, Lundy FT. Neuropeptide Y Y1 receptor in human dental pulp cells of noncarious and carious teeth. Int Endod J 2008; 41:850-5. [PMID: 18699789 DOI: 10.1111/j.1365-2591.2008.01436.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To determine the distribution of the NPY Y1 receptor in carious and noncarious human dental pulp tissue using immunohistochemistry. A subsidiary aim was to confirm the presence of the NPY Y1 protein product in membrane fractions of dental pulp tissue from carious and noncarious teeth using western blotting. METHODOLOGY Twenty two dental pulp samples were collected from carious and noncarious extracted teeth. Ten samples were processed for immunohistochemistry using a specific antibody to the NPY Y1 receptor. Twelve samples were used to obtain membrane extracts which were electrophoresed, blotted onto nitrocellulose and probed with NPY Y1 receptor antibody. Kruskal-Wallis one-way analysis of variance was employed to test for overall statistical differences between NPY Y1 levels in noncarious, moderately carious and grossly carious teeth. RESULTS Neuropeptide Y Y1 receptor immunoreactivity was detected on the walls of blood vessels in pulp tissue from noncarious teeth. In carious teeth NPY Y1 immunoreactivity was observed on nerve fibres, blood vessels and inflammatory cells. Western blotting indicated the presence and confirmed the variability of NPY Y1 receptor protein expression in solubilised membrane preparations of human dental pulp tissue from carious and noncarious teeth. CONCLUSIONS Neuropeptide Y Y1 is expressed in human dental pulp tissue with evidence of increased expression in carious compared with noncarious teeth, suggesting a role for NPY Y1 in modulation of caries induced pulpal inflammation.
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Affiliation(s)
- I A El Karim
- Oral Science Research Centre, School of Medicine and Dentistry, Queen's University, Belfast, Northern Ireland, UK
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Cox HM. Endogenous PYY and NPY mediate tonic Y1- and Y2-mediated absorption in human and mouse colon. Nutrition 2008; 24:900-6. [PMID: 18662856 PMCID: PMC2572019 DOI: 10.1016/j.nut.2008.06.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Accepted: 06/13/2008] [Indexed: 02/07/2023]
Abstract
Objective To establish the functional significance of endogenous peptide YY (PYY) and neuropeptide Y (NPY) as mediators of Y1 and Y2 absorptive tone in colonic mucosa. Methods Functional studies utilized descending colon from adult mice (wild type [WT] and peptide nulls) and ex vivo human colonic tissue (from patients undergoing bowel resections) measuring changes in basal ion transport. Peak increases in ion transport to Y1 or Y2 antagonists (BIBO3304 300 nM; BIIE0246 1 μM) were pooled (mean ± SEM) and compared using Student's unpaired t test (P ≤ 0.05); some tissues received tetrodotoxin (TTX; 100 nM). PYY-positive L-cell numbers and NPY innervation were also compared. Results Y1 and Y2 tones were present in human and WT mouse colon mucosa and only the latter was TTX sensitive. Y1 tone was unchanged in NPY−/− but was ∼90% inhibited in PYY−/− and abolished in PYYNPY−/− colon mucosa. Y2 tone was reduced ∼50% in NPY−/− and PYY−/− tissues and was absent from PYYNPY−/− colon. Residual Y2 and Y1 tones present in PYY−/− mucosa were abolished by TTX. PYY ablation had no apparent effect on NPY innervation and PYY-positive cells were observed at the same frequency in NPY−/− (56.7 ± 6.8 cells/section) and WT (55.0 ± 4.6 cells/section) colons. Double knockouts lacked PYY and NPY expression, but endocrine cells and enteric nerves were present with similar frequencies to those of WT mice. Conclusion Endogenous PYY mediates Y1 absorptive tone that is epithelial in origin, whereas Y2 tone is a combination of PYY and NPY mediation.
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Affiliation(s)
- Helen M Cox
- King's College London, Wolfson Centre for Age-Related Diseases, Guy's Campus, London, United Kingdom.
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14
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Abstract
Endocrine cells, enteric neurons and enterocytes provide an integrated functional defense against luminal factors, including nutrients, microbes and toxins. Prominent among intrinsic mediators is peptide YY (PYY) which is present in approximately 50% of colorectal endocrine cells and neuropeptide Y (NPY), a neurotransmitter expressed in submucous and myenteric nerves. Both peptides and their long fragments (PYY(3-36) and NPY(3-36)) are potent, long-lasting anti-secretory agents in vitro and in vivo and, they provide significant Y receptor-mediated absorptive tone in human and mouse colon mucosa. The main function of the colon is to absorb 90% of approximately 2l of daily ileal effluent (in adult humans) and Y-absorptive tone can contribute significantly to this electrolyte absorption. Blockade or loss of this mucosal Y-absorptive tone (i.e. with Y(1) or Y(2) antagonists) leads to hypersecretion and potentially to diarrhea, so Y agonists are predicted to rescue absorption by mimicking endogenous neuroendocrine PYY or neuronal NPY.
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Affiliation(s)
- Helen M Cox
- Wolfson Centre for Age-Related Diseases, King's College London, School of Biomedical and Health Sciences, Guy's Campus, Hodgkin Building, London SE1 1UL, UK.
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15
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Cox HM. Neuropeptide Y receptors; antisecretory control of intestinal epithelial function. Auton Neurosci 2006; 133:76-85. [PMID: 17140858 DOI: 10.1016/j.autneu.2006.10.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Revised: 09/12/2006] [Accepted: 10/23/2006] [Indexed: 12/11/2022]
Abstract
This paper reviews the cellular localisation, mechanisms of release and intestinal absorptive actions of neuropeptide Y and its related peptides, peptide YY, pancreatic polypeptide and major fragments NPY(3-36) and PYY(3-36). While NPY is commonly found in inhibitory enteric neurons that can be interneurons, motor neurons or secretomotor-nonvasodilator in nature, its analogue, peptide YY in contrast, is located in neuroendocrine L-cells that predominate in the colorectal mucosa. Peptide YY is released from these cells when nutrients arrive in the small or large bowel, exerting paracrine as well as hormonal actions. Pancreatic polypeptide is found in relatively few, scattered intestinal endocrine cells, the majority of this peptide being produced by, and released from pancreatic islet F-cells in response to food intake. An introduction to the current pharmacology of this family of peptides is provided and the different types of neuropeptide Y (termed Y) receptors, their agonist preferences, antagonism, and preferred signalling pathways, are described. Our current understanding of specific Y receptor localisation within the intestine as determined by immunohistochemistry, is presented as a prelude to an assessment of functional studies that have monitored ion transport across isolated mucosal preparations. It is becoming clear that three Y receptor types are significant functionally in human colon, as well as particular rodent models (e.g. mouse) and these, namely the Y(1), Y(2) and Y(4) receptors, are discussed in detail. Their presence within the basolateral aspect of the epithelial layer (Y(1) and Y(4) receptors) or on enteric neurons (Y(1) and Y(2) receptors) and their activation by endogenous neuropeptide Y, peptide YY (Y(1) and Y(2) receptors) or pancreatic polypeptide (which prefers Y(4) receptors) results consistently in antisecretory/absorptive responses. The recent use of novel mouse knockouts has helped establish loss of specific intestinal functions including Y(1) and Y(2) receptor-mediated absorptive tone in colon mucosa. Progress in this field has been rapid recently, aided by the availability of selective antagonists and mutant mice lacking either one (e.g. Y(4)-/-, for which no antagonists exist at present) or more Y receptor types. It is therefore timely to review this work and present a rational basis for developing stable synthetic Y receptor agonists as novel anti-diarrhoeals.
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Affiliation(s)
- Helen M Cox
- Wolfson Centre for Age-Related Diseases, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, United Kingdom.
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Hyland NP, Cox HM. The regulation of veratridine-stimulated electrogenic ion transport in mouse colon by neuropeptide Y (NPY), Y1 and Y2 receptors. Br J Pharmacol 2006; 146:712-22. [PMID: 16100526 PMCID: PMC1751203 DOI: 10.1038/sj.bjp.0706368] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
1 Neuropeptide Y (NPY) is a prominent enteric neuropeptide with prolonged antisecretory effects in mammalian intestine. Veratridine depolarises neurons consequently causing epithelial anion secretion across mouse colon mucosa. Our aim was to characterise functionally, veratridine-stimulated mucosal responses and to determine the roles for NPY, Y(1), and Y(2) receptors in modulating these neurogenic effects. 2 Colon mucosae (with intact submucous innervation) from wild-type mice (+/+) and knockouts lacking either NPY (NPY-/-), Y(1)-/- or Y(2)-/- were placed in Ussing chambers and voltage clamped at 0 mV. Veratridine-stimulated short-circuit current (I(sc)) responses in +/+, Y(1) or Y(2) antagonist pretreated +/+ colon, Y(1)-/- and NPY-/- colon were insensitive to cholinergic blockade by atropine (At; 1 microM) and hexamethonium (Hex; 10 microM). Tetrodotoxin (TTX, 100 nM) abolished veratridine responses, but had no effect upon carbachol (CCh) or vasoactive intestinal polypeptide (VIP)-induced secretory responses. 3 To establish the functional roles for Y(1) and Y(2) receptors, +/+ tissues were pretreated with either the Y(1) or Y(2) receptor antagonist (BIBO3304 (300 nM) or BIIE0246 (1 microM), respectively) and veratridine responses were compared with those from Y(1)-/- or Y(2)-/- colon. Neither BIBO3304 nor Y(1)-/- altered veratridine-induced secretion, but Y(1) agonist responses were abolished in both preparations. In contrast, the Y(2) antagonist BIIE0246 significantly amplified veratridine responses in +/+ mucosa. Unexpectedly, NPY-/- colon exhibited significantly attenuated veratridine responses (between 1 and 5 min). 4 We demonstrate that electrogenic veratridine responses in mouse colon are noncholinergic and that NPY can act directly upon epithelia, a Y(1) receptor effect. The enhanced veratridine response observed in +/+ tissue following BIIE0246, indicates that Y(2) receptors are located on submucosal neurons and that their activation by NPY will inhibit enteric noncholinergic secretory neurotransmission. 5 We also demonstrate Y(1) and Y(2) receptor-mediated antisecretory tone in +/+ colon and show selective loss of each in Y(1) and Y(2) null colon respectively. In NPY-/- tissue, only Y(1)-mediated tone was present, this presumably being mediated by endogenous endocrine peptide YY. Y(2) tone was absent from NPY-/- (and Y(2)-/-) colon and we conclude that NPY activation of neuronal Y(2) receptors attenuates secretory neurotransmission thereby providing an absorptive electrolyte tone in isolated colon.
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Affiliation(s)
- Niall P Hyland
- Wolfson Centre for Age-Related Diseases, King's College London, GKT School of Biomedical Sciences, Guy's Campus, London, SE1 1UL
| | - Helen M Cox
- Wolfson Centre for Age-Related Diseases, King's College London, GKT School of Biomedical Sciences, Guy's Campus, London, SE1 1UL
- Author for correspondence:
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Abstract
Diagnostic tools for paediatric chronic constipation have been limited, leading to over 90% of patients with treatment-resistant constipation being diagnosed with chronic idiopathic constipation, with no discernible organic cause. Work in our institution suggests that a number of children with intractable symptoms actually have slow colonic transit leading to slow transit constipation. This paper reviews recent data suggesting that a significant number of the children with chronic treatment-resistant constipation may have organic causes (slow colonic transit and outlet obstruction) and suggests new approaches to the management of children with chronic treatment-resistant constipation.
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Affiliation(s)
- B R Southwell
- Department of Gastroenterology, Royal Children's Hospital, Melbourne, Victoria, Australia
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Hyland NP, Sjöberg F, Tough IR, Herzog H, Cox HM. Functional consequences of neuropeptide Y Y 2 receptor knockout and Y2 antagonism in mouse and human colonic tissues. Br J Pharmacol 2003; 139:863-71. [PMID: 12813010 PMCID: PMC1573894 DOI: 10.1038/sj.bjp.0705298] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
1 Neuropeptide Y (NPY), peptide YY (PYY) and pancreatic polypeptide (PP) differentially activate three Y receptors (Y(1), Y(2) and Y(4)) in mouse and human isolated colon. 2 The aim of this study was to characterise Y(2) receptor-mediated responses in colon mucosa and longitudinal smooth muscle preparations from wild type (Y(2)+/+) and knockout (Y(2)-/-) mice and to compare the former with human mucosal Y agonist responses. Inhibition of mucosal short-circuit current and increases in muscle tone were monitored in colonic tissues from Y(2)+/+ and Y(2)-/- mice+/-Y(1) ((R)-N-[[4-(aminocarbonylaminomethyl)phenyl)methyl]-N(2)-(diphenylacetyl)-argininamide-trifluoroacetate (BIBO3304) or Y(2) (S)-N(2)-[[1-[2-[4-[(R,S)-5,11-dihydro-6(6H)-oxodibenz[b,e]azepin-11-yl]-1-piperazinyl]-2-oxoethyl]cyclopentyl]acetyl]-N-[2-[1,2-dihydro-3,5(4H)-dioxo-1,2-diphenyl-3H-1,2,4-triazol-4-yl]ethyl]-argininamide (BIIE0246) antagonists. 3 Predictably, Y(2)-/- tissues were insensitive to Y(2)-preferred agonist PYY(3-36) (</=100 nM), but unexpectedly Y(4)-preferred PP responses were right-shifted probably as a consequence of elevated circulating PP levels, particularly in male Y(2)-/- mice (Sainsbury et al., 2002). 4 BIBO3304 and BIIE0246 elevated mucosal ion transport, indicating blockade of inhibitory mucosal tone in Y(2)+/+ tissue. While BIBO3304 effects were unchanged, those to BIIE0246 were absent in Y(2)-/- mucosae. Neither antagonist altered muscle tone; however, BIIE0246 blocked NPY and PYY(3-36) increases in Y(2)+/+ basal tone. BIBO3304 abolished residual Y(1)-mediated NPY responses in Y(2)-/- smooth muscle. 5 Tetrodotoxin significantly reduced BIIE0246 and PYY(3-36) effects in Y(2)+/+ mouse and human mucosae, but had no effect upon Y-agonist contractile responses, indicating that Y(2) receptors are located on submucosal, but not myenteric neurones. 6 Tonic activation of submucosal Y(2) receptors by endogenous NPY, PYY or PYY(3-36) could indirectly reduce mucosal ion transport in murine and human colon, while direct activation of Y(2) receptors on longitudinal muscle results in contraction.
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Affiliation(s)
- Niall P Hyland
- Centre for Neuroscience Research, King's College London, GKT School of Biomedical Sciences, Guy's Campus, London SE1 1UL
| | - Frida Sjöberg
- Centre for Neuroscience Research, King's College London, GKT School of Biomedical Sciences, Guy's Campus, London SE1 1UL
| | - Iain R Tough
- Centre for Neuroscience Research, King's College London, GKT School of Biomedical Sciences, Guy's Campus, London SE1 1UL
| | - Herbert Herzog
- Neurobiology Program, Garvan Institute of Medical Research, 384, Victoria Street, NSW 2010, Sydney, Australia
| | - Helen M Cox
- Centre for Neuroscience Research, King's College London, GKT School of Biomedical Sciences, Guy's Campus, London SE1 1UL
- Author for correspondence:
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Ferrier L, Segain JP, Bonnet C, Cherbut C, Lehur PA, Jarry A, Galmiche JP, Blottiere HM. Functional mapping of NPY/PYY receptors in rat and human gastro-intestinal tract. Peptides 2002; 23:1765-71. [PMID: 12383864 DOI: 10.1016/s0196-9781(02)00133-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Peptide YY (PYY) is involved in the regulation of several gastro-intestinal functions, including motility. The aims of the present study were (i) to characterize the effects of PYY on smooth muscle strips obtained from the different gastro-intestinal segments in rats and in humans and (ii) to realize a map of the Y receptors expression. Contractions of strips were recorded under isometric conditions, using PYY and acetylcholine as control. We observed that PYY induced a contraction of muscle strips from rat proximal colon, but displayed no effect on other gut segments. Using RT-PCR, mRNA encoding the Y1 and Y4 receptors were detected in muscle strips depending on the segment. In humans, the muscle preparations responded to ACh but not to PYY. Moreover, only Y2 receptor mRNA was found in the ileum and the left colon, but not in other segments. Our study shows the heterogeneity in the expression of Y receptors along the gastro-intestinal tract, and reveals great discrepancies between rats and humans both concerning the expression of Y receptor, and the response of smooth muscle strips to PYY.
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Affiliation(s)
- Laurent Ferrier
- Centre de Recherche en Nutrition Humaine, INSERM U539, CHU-Hôtel Dieu, 44093 Nantes, France.
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Blumenthal JB, Andersen RE, Mitchell BD, Seibert MJ, Yang H, Herzog H, Beamer BA, Franckowiak SC, Walston JD. Novel neuropeptide Y1 and Y5 receptor gene variants: associations with serum triglyceride and high-density lipoprotein cholesterol levels. Clin Genet 2002; 62:196-202. [PMID: 12220433 DOI: 10.1034/j.1399-0004.2002.620302.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Neuropeptide Y (NPY) appears to play a critical role in the integration of appetite and energy expenditure through NPY Y1 and Y5 receptor subtypes. Moreover, the NPY Y1 receptor is highly expressed on human adipocytes, where it inhibits lipolysis. The genes encoding these receptors are transcribed co-ordinately in opposite directions from a common promoter in a region of chromosome 4 that has been previously linked to triglyceride and small low-density lipoprotein (LDL) particle concentration. Therefore, the purpose of this investigation was to examine the relationship between polymorphisms in the genes encoding NPY Y1 and Y5 and the development of obesity and dyslipidemia. We screened the promoter and coding regions and identified four polymorphic variants. One of these, a cytosine to thymine (C-->T) substitution in the untranslated region between the genes for NPY Y1 and Y5 (allele frequency 0.11), was significantly associated with both lower fasting triglyceride level (152 vs 125 mg/dl), and higher high-density lipoprotein (HDL) concentrations (49 vs 45 mg/dl) (p < 0.01) in 306 obese subjects. Given the stimulatory effect of NPY on adipocyte lipoprotein lipase (LPL) activity, and the lack of association of other polymorphisms with serum lipid levels, we hypothesize that this is a gain-in-function polymorphism.
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Affiliation(s)
- J B Blumenthal
- Division of Geriatric Medicine and Gerontology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21224, USA
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Cox HM, Tough IR. Neuropeptide Y, Y1, Y2 and Y4 receptors mediate Y agonist responses in isolated human colon mucosa. Br J Pharmacol 2002; 135:1505-12. [PMID: 11906964 PMCID: PMC1573267 DOI: 10.1038/sj.bjp.0704604] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
1. The aim of this study was to provide a pharmacological characterization of the Y receptor types responsible for neuropeptide Y (NPY), peptide YY (PYY) and pancreatic polypeptide (PP) effects upon electrogenic ion transport in isolated human colonic mucosa. 2. Preparations of descending colon were voltage-clamped at 0 mV in Ussing chambers and changes in short-circuit current (I(sc)) continuously recorded. Basolateral PYY, NPY, human PP (hPP), PYY(3 - 36), [Leu(31), Pro(34)]PYY (Pro(34)PYY) and [Leu(31), Pro(34)]-NPY (Pro(34)NPY) all reduced basal I(sc) in untreated colon. Of all the Y agonists tested PYY(3 - 36) responses were most sensitive to tetrodotoxin (TTX) pretreatment, indicating that Y(2)-receptors are located on intrinsic neurones as well as epithelia in this tissue. 3. The EC(50) values for Pro(34)PYY, PYY(3 - 36) and hPP were 9.7 nM (4.0 - 23.5), 11.4 nM (7.6 - 17.0) and 14.5 nM (10.2 - 20.5) and response curves exhibited similar efficacies. The novel Y(5) agonist [Ala(31), Aib(32)]-NPY had no effect at 100 nM. 4. Y(1) receptor antagonists, BIBP3226 and BIBO3304 both increased basal I(sc) levels per se and inhibited subsequent PYY and Pro(34)PYY but not hPP or PYY(3 - 36) responses. The Y(2) antagonist, BIIE0246 also raised basal I(sc) levels and attenuated subsequent PYY(3 - 36) but not Pro(34)PYY or hPP responses. 5. We conclude that Y(1) and Y(2) receptor-mediated inhibitory tone exists in human colon mucosa. PYY and NPY exert their effects via both Y(1) and Y(2) receptors, but the insensitivity of hPP responses to either Y(1) or Y(2) antagonism, or to TTX, indicates that Y(4) receptors are involved and that they are predominantly post-junctional in human colon.
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Affiliation(s)
- Helen M Cox
- Centre for Neuroscience Research, King's College London, GKT School of Biomedical Sciences, Hodgkin Building, Guy's Campus, London SE1 9RT, UK.
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Abstract
Peptide YY is an abundant distal gut hormone that may play a significant role in intestinal epithelial proliferation. Gut epithelial cells express specific receptors for PYY, PYY induces proliferation in intestinal cells in vivo and in vitro, and the Y1 receptor subtype couples to mitogenic signaling pathways. In addition to proposed physiologic effects on gut mucosal maintenance, PYY proliferative effects may be hypothesized to contribute to pathophysiologic consequences of stimulated growth.
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Affiliation(s)
- Peter J Mannon
- Mucosal Immunity Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Abstract
Peptide YY (PYY) is a naturally occurring gut hormone with mostly inhibitory actions on multiple tissue targets. PYY has been identified in several carcinoid tumors and a decreased expression of PYY may be relevant to the development and progression of colon adenocarcinoma. Treatment with PYY decreases growth in pancreatic and breast tumors, most likely through a reduction in intracellular cAMP. In cancer patients, PYY may also improve malnutrition that results from iatrogenic causes or cachexia associated with advanced disease. PYY plays a significant role in multiple aspects of cancer from regulation of cell growth to potential therapeutic applications.
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Affiliation(s)
- William W Tseng
- Northwestern University Medical School, Chicago, Illinois 60611, USA
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Abstract
INTRODUCTION Gastric emptying is delayed in patients with idiopathic slow-transit constipation (ISTC). Gastric emptying was measured before and after colectomy and ileorectal anastomosis in patients with ISTC to determine whether the abnormality persists after operation. METHODS Twelve patients undergoing colectomy for severe ISTC had solid-phase gastric emptying measured after an overnight fast. All 12 had an uncomplicated subtotal colectomy and ileorectal anastomosis; 11 had an excellent functional outcome. In ten of these patients gastric emptying was repeated within 3 months of operation. Seven patients (including the remaining two) had the study performed at 1 year. RESULTS All 12 patients had severely delayed gastric emptying before operation. Gastric emptying remained delayed in the ten patients who underwent an early postoperative gastric emptying study. Six of seven patients assessed at 1 year had improved gastric emptying, of whom four had returned to normal. Functional outcome did not relate to gastric emptying. CONCLUSION Patients with ISTC have delayed gastric emptying. In some patients this returns to normal after colectomy, but is persistent in others. This may have implications for our understanding of ISTC.
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Affiliation(s)
- D M Hemingway
- Department of Coloproctology, Glasgow Royal Infirmary, Glasgow, UK
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