1
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Zomer HD, Cooke PS. Advances in Drug Treatments for Companion Animal Obesity. BIOLOGY 2024; 13:335. [PMID: 38785817 PMCID: PMC11117622 DOI: 10.3390/biology13050335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/06/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024]
Abstract
Companion animal obesity has emerged as a significant veterinary health concern globally, with escalating rates posing challenges for preventive and therapeutic interventions. Obesity not only leads to immediate health problems but also contributes to various comorbidities affecting animal well-being and longevity, with consequent emotional and financial burdens on owners. While past treatment strategies have shown limited success, recent breakthroughs in human medicine present new opportunities for addressing this complex issue in companion animals. Here, we discuss the potential of GLP-1 receptor agonists, specifically semaglutide and tirzepatide, already approved for human use, for addressing companion animal obesity. These drugs, originally developed to treat type 2 diabetes in humans and subsequently repurposed to treat obesity, have demonstrated remarkable weight loss effects in rodents, non-human primates and people. Additionally, newer drug combinations have shown even more promising results in clinical trials. Despite current cost and supply challenges, advancements in oral and/or extended-release formulations and increased production may make these drugs more accessible for veterinary use. Thus, these drugs may have utility in companion animal weight management, and future feasibility studies exploring their efficacy and safety in treating companion animal obesity are warranted.
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Affiliation(s)
| | - Paul S. Cooke
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32610, USA;
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2
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Abstract
Incretin hormones (glucose-dependent insulinotropic polypeptide [GIP] and glucagon-like peptide-1 [GLP-1]) play a role in the pathophysiology of type 2 diabetes. Along with their derivatives they have shown therapeutic success in type 2 diabetes, with the potential for further improvements in glycaemic, cardiorenal and body weight-related outcomes. In type 2 diabetes, the incretin effect (greater insulin secretory response after oral glucose than with 'isoglycaemic' i.v. glucose, i.e. with an identical glycaemic stimulus) is markedly reduced or absent. This appears to be because of a reduced ability of GIP to stimulate insulin secretion, related either to an overall impairment of beta cell function or to specific defects in the GIP signalling pathway. It is likely that a reduced incretin effect impacts on postprandial glycaemic excursions and, thus, may play a role in the deterioration of glycaemic control. In contrast, the insulinotropic potency of GLP-1 appears to be much less impaired, such that exogenous GLP-1 can stimulate insulin secretion, suppress glucagon secretion and reduce plasma glucose concentrations in the fasting and postprandial states. This has led to the development of incretin-based glucose-lowering medications (selective GLP-1 receptor agonists or, more recently, co-agonists, e.g. that stimulate GIP and GLP-1 receptors). Tirzepatide (a GIP/GLP-1 receptor co-agonist), for example, reduces HbA1c and body weight in individuals with type 2 diabetes more effectively than selective GLP-1 receptor agonists (e.g. semaglutide). The mechanisms by which GIP receptor agonism may contribute to better glycaemic control and weight loss after long-term exposure to tirzepatide are a matter of active research and may change the pessimistic view that developed after the disappointing lack of insulinotropic activity in people with type 2 diabetes when exposed to GIP in short-term experiments. Future medications that stimulate incretin hormone and other receptors simultaneously may have the potential to further increase the ability to control plasma glucose concentrations and induce weight loss.
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Affiliation(s)
- Michael A Nauck
- Diabetes, Endocrinology, Metabolism Section, Medical Department I, Katholisches Klinikum Bochum, St. Josef Hospital, Ruhr-University Bochum, Bochum, Germany.
- Institute for Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany.
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), München Neuherberg, Germany
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3
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Madsbad S, Knop FK, Holst JJ. Does glucose lowering restore GIP's effect on insulin secretion? Nutr Metab Cardiovasc Dis 2023; 33:1817-1818. [PMID: 37150733 DOI: 10.1016/j.numecd.2023.03.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 03/27/2023] [Indexed: 05/09/2023]
Affiliation(s)
- Sten Madsbad
- Department of Endocrinology, Hvidovre Hospital, University of Copenhagen, Hvidovre, Copenhagen, Denmark.
| | - Filip K Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, University of Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Denmark
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4
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El K, Douros JD, Willard FS, Novikoff A, Sargsyan A, Perez-Tilve D, Wainscott DB, Yang B, Chen A, Wothe D, Coupland C, Tschöp MH, Finan B, D'Alessio DA, Sloop KW, Müller TD, Campbell JE. The incretin co-agonist tirzepatide requires GIPR for hormone secretion from human islets. Nat Metab 2023; 5:945-954. [PMID: 37277609 PMCID: PMC10290954 DOI: 10.1038/s42255-023-00811-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 04/21/2023] [Indexed: 06/07/2023]
Abstract
The incretins glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) mediate insulin responses that are proportionate to nutrient intake to facilitate glucose tolerance1. The GLP-1 receptor (GLP-1R) is an established drug target for the treatment of diabetes and obesity2, whereas the therapeutic potential of the GIP receptor (GIPR) is a subject of debate. Tirzepatide is an agonist at both the GIPR and GLP-1R and is a highly effective treatment for type 2 diabetes and obesity3,4. However, although tirzepatide activates GIPR in cell lines and mouse models, it is not clear whether or how dual agonism contributes to its therapeutic benefit. Islet beta cells express both the GLP-1R and the GIPR, and insulin secretion is an established mechanism by which incretin agonists improve glycemic control5. Here, we show that in mouse islets, tirzepatide stimulates insulin secretion predominantly through the GLP-1R, owing to reduced potency at the mouse GIPR. However, in human islets, antagonizing GIPR activity consistently decreases the insulin response to tirzepatide. Moreover, tirzepatide enhances glucagon secretion and somatostatin secretion in human islets. These data demonstrate that tirzepatide stimulates islet hormone secretion from human islets through both incretin receptors.
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Affiliation(s)
- Kimberley El
- Duke Molecular Physiology Institute, Durham, NC, USA
| | | | - Francis S Willard
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Aaron Novikoff
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | | | - Diego Perez-Tilve
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - David B Wainscott
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | - Bin Yang
- Novo Nordisk Research Center, Indianapolis, IN, USA
| | - Alex Chen
- Duke Molecular Physiology Institute, Durham, NC, USA
| | - Donald Wothe
- Duke Molecular Physiology Institute, Durham, NC, USA
| | - Callum Coupland
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Mattias H Tschöp
- Helmholtz Zentum München, Neuherberg, Germany
- Technische Universität München, München, Germany
| | - Brian Finan
- Novo Nordisk Research Center, Indianapolis, IN, USA
| | - David A D'Alessio
- Duke Molecular Physiology Institute, Durham, NC, USA
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC, USA
| | - Kyle W Sloop
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA.
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), Neuherberg, Germany.
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Durham, NC, USA.
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC, USA.
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, USA.
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5
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Grespan E, Mari A. Does glucose lowering restore GIP effects on insulin secretion? Nutr Metab Cardiovasc Dis 2023; 33:494-499. [PMID: 36710118 DOI: 10.1016/j.numecd.2022.12.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/23/2022] [Accepted: 12/28/2022] [Indexed: 01/11/2023]
Abstract
AIMS Some studies have shown that in type 2 diabetic patients the potentiation of insulin secretion by glucose-dependent insulinotropic polypeptide (GIP) is compromised but can be partially restored if glucose is lowered. Renewed interest for this phenomenon has been expressed in the context of the new dual GIP-GLP-1 (glucagon-like peptide-1) receptor agonists, which have shown greater efficacy of this drug class compared with single GLP-1 receptor agonists, including on insulin secretion. However, contrasting evidence has been reported on the recovery of GIP action with glucose lowering. In our study, we reconsider all publications relevant for the problem and analyze the results using a uniform methodology. DATA SYNTHESIS We show that, while some contradictions might be explained by heterogeneous analysis methods, it is possible to interpret all the available data coherently and conclude that the effect of glucose lowering is relevant only when glucose concentration is virtually normalized. CONCLUSIONS While a significant restoration of GIP action may not occur with some traditional diabetes treatments, GIP action improvement might become relevant when glucose is virtually normalized and could explain part of the success of the double GIP-GLP-1 receptor agonists.
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Affiliation(s)
- Eleonora Grespan
- Institute of Neuroscience, National Research Council, Padua, Italy.
| | - Andrea Mari
- Institute of Neuroscience, National Research Council, Padua, Italy.
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Venneti NM, Samala G, Morsy RMI, Mendoza LG, Isidro-Llobet A, Tom JK, Mukherjee S, Kopach ME, Stockdill JL. Phosphine-Dependent Photoinitiation of Alkyl Thiols under Near-UV Light Facilitates User-Friendly Peptide Desulfurization. J Am Chem Soc 2023; 145:1053-1061. [PMID: 36602440 DOI: 10.1021/jacs.2c10625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Peptides are steadily gaining importance as pharmaceutical targets, and efficient, green methods for their preparation are critically needed. A key deficiency in the synthetic toolbox is the lack of an industrially viable peptide desulfurization method. Without this tool, the powerful native chemical ligation reaction typically used to assemble polypeptides and proteins remains out of reach for industrial preparation of drug targets. Current desulfurization methods require very large excesses of phosphine reagents and thiol additives or low-abundance metal catalysts. Here, we report a phosphine-only photodesulfurization (POP) using near-UV light that is clean, high-yielding, and requires as little as 1.2 equiv phosphine. The user-friendly reaction gives complete control to the chemist, allowing solvent and reagent selection based on starting material and phosphine solubility. It can be conducted in a range of solvents, including water or buffers, on protected or unprotected peptides, in low or high dilution and on gram scale. Oxidation-prone amino acids, π-bonds, aromatic rings, thio-aminal linkages, thioesters, and glycans are all stable to the POP reaction. We highlight the utility of this approach for desulfurization of industrially relevant targets including cyclic peptides and glucagon-like peptide 1 (GLP-1(7-36)). The method is also compatible with NCL buffer, and we highlight the robustness of the approach through the one-pot disulfide reduction/multidesulfurization of linaclotide, aprotinin, and wheat protein.
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Affiliation(s)
- Naresh M Venneti
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Ganesh Samala
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Rana M I Morsy
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Lawrence G Mendoza
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | | | - Janine K Tom
- Amgen, Inc., Pivotal Drug Substance Process Development, Thousand Oaks, California 91320, United States
| | - Subha Mukherjee
- Bristol-Myers Squibb, Chemical and Synthetic Development, New Brunswick, New Jersey 08903, United States
| | - Michael E Kopach
- Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Jennifer L Stockdill
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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7
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De Block C, Bailey C, Wysham C, Hemmingway A, Allen SE, Peleshok J. Tirzepatide for the treatment of adults with type 2 diabetes: An endocrine perspective. Diabetes Obes Metab 2023; 25:3-17. [PMID: 35929488 PMCID: PMC10087310 DOI: 10.1111/dom.14831] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/26/2022] [Accepted: 08/02/2022] [Indexed: 02/06/2023]
Abstract
Tirzepatide is a novel glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 (GLP-1) receptor agonist approved in the United States as an adjunct to diet and exercise to improve glycaemic control in adults with type 2 diabetes and under investigation for use in chronic weight management, major adverse cardiovascular events and the management of other conditions, including heart failure with preserved ejection fraction and obesity and non-cirrhotic non-alcoholic steatohepatitis. The Phase 3 SURPASS 1-5 clinical trial programme was designed to assess efficacy and safety of once-weekly subcutaneously injected tirzepatide (5, 10 and 15 mg), as monotherapy or combination therapy, across a broad spectrum of people with type 2 diabetes. Use of tirzepatide in clinical studies was associated with marked reductions of glycated haemoglobin (-1.87 to -2.59%, -20 to -28 mmol/mol) and body weight (-6.2 to -12.9 kg), as well as reductions in parameters commonly associated with heightened cardiometabolic risk such as blood pressure, visceral adiposity and circulating triglycerides. In SUPRASS-2, these reductions were greater than with the GLP-1 receptor agonist semaglutide 1 mg. Tirzepatide was well tolerated, with a low risk of hypoglycaemia when used without insulin or insulin secretagogues and showed a generally similar safety profile to the GLP-1 receptor agonist class. Accordingly, evidence from these clinical trials suggests that tirzepatide offers a new opportunity for the effective lowering of glycated haemoglobin and body weight in adults with type 2 diabetes.
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Affiliation(s)
- Christophe De Block
- Department of Endocrinology, Diabetology and Metabolism, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
- Faculty of Medicine and Health Sciences, Laboratory of Experimental Medicine and Paediatrics (LEMP), University of Antwerp, Wilrijk, Belgium
| | | | - Carol Wysham
- Section of Endocrinology and Metabolism, MultiCare Rockwood Clinic, Spokane, WA, USA
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8
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Mayendraraj A, Rosenkilde MM, Gasbjerg LS. GLP-1 and GIP receptor signaling in beta cells - A review of receptor interactions and co-stimulation. Peptides 2022; 151:170749. [PMID: 35065096 DOI: 10.1016/j.peptides.2022.170749] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 02/07/2023]
Abstract
Glucagon-like peptide 1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) are two class B1 G protein-coupled receptors, which are stimulated by the gastrointestinal hormones GLP-1 and GIP, respectively. In the pancreatic beta cells, activation of both receptors lead to increased cyclic adenosine monophosphate (cAMP) and glucose-dependent insulin secretion. Marketed GLP-1R agonists such as dulaglutide, liraglutide, exenatide and semaglutide constitute an expanding drug class with beneficial effects for persons suffering from type 2 diabetes and/or obesity. In recent years another drug class, the GLP-1R-GIPR co-agonists, has emerged. Especially the peptide-based, co-agonist tirzepatide is a promising candidate for a better treatment of type 2 diabetes by improving glycemic control and weight reduction. The mechanism of action for tirzepatide include biased signaling of the GLP-1R as well as potent GIPR signaling. Since the implications of co-targeting these closely related receptors concomitantly are challenging to study in vivo, the pharmacodynamic mechanisms and downstream signaling pathways of the GLP-1R-GIPR co-agonists in general, are not fully elucidated. In this review, we present the individual signaling pathways for GLP-1R and GIPR in the pancreatic beta cell with a focus on the shared signaling pathways of the two receptors and interpret the implications of GLP-1R-GIPR co-activation in the light of recent co-activating therapeutic compounds.
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Affiliation(s)
- Ashok Mayendraraj
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lærke S Gasbjerg
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
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9
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Liang H, Yang L, Wang X, Zhou Z. Response to the Letter to the Editor from Valdemar Grill et al: "Islet Function and Insulin Sensitivity in Latent Autoimmune Diabetes in Adults Taking Sitagliptin: A Randomized Trial". J Clin Endocrinol Metab 2021; 106:e4304-e4305. [PMID: 34114619 PMCID: PMC8475198 DOI: 10.1210/clinem/dgab413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Indexed: 11/25/2022]
Affiliation(s)
- Huiying Liang
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Affiliated Dongguan People’s Hospital, Southern Medical University (Dongguan People’s Hospital), Dongguan, Guangdong, China
| | - Lin Yang
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Xiangbing Wang
- Division of Endocrinology, Metabolism and Nutrition, Rutgers University-Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Zhiguang Zhou
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Correspondence: Zhiguang Zhou, MD, PhD, Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, No.139 Renmin Road, Changsha 410011, Hunan, China. E-mail:
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10
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Holst JJ, Gasbjerg LS, Rosenkilde MM. The Role of Incretins on Insulin Function and Glucose Homeostasis. Endocrinology 2021; 162:6199910. [PMID: 33782700 PMCID: PMC8168943 DOI: 10.1210/endocr/bqab065] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Indexed: 12/14/2022]
Abstract
The incretin effect-the amplification of insulin secretion after oral vs intravenous administration of glucose as a mean to improve glucose tolerance-was suspected even before insulin was discovered, and today we know that the effect is due to the secretion of 2 insulinotropic peptides, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). But how important is it? Physiological experiments have shown that, because of the incretin effect, we can ingest increasing amounts of amounts of glucose (carbohydrates) without increasing postprandial glucose excursions, which otherwise might have severe consequences. The mechanism behind this is incretin-stimulated insulin secretion. The availability of antagonists for GLP-1 and most recently also for GIP has made it possible to directly estimate the individual contributions to postprandial insulin secretion of a) glucose itself: 26%; b) GIP: 45%; and c) GLP-1: 29%. Thus, in healthy individuals, GIP is the champion. When the action of both incretins is prevented, glucose tolerance is pathologically impaired. Thus, after 100 years of research, we now know that insulinotropic hormones from the gut are indispensable for normal glucose tolerance. The loss of the incretin effect in type 2 diabetes, therefore, contributes greatly to the impaired postprandial glucose control.
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Affiliation(s)
- Jens Juul Holst
- Department of Biomedical Sciences and the NovoNordisk Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, The Panum Institute, Copenhagen N, DK-2200 Denmark
- Correspondence: Jens Juul Holst, MD, University of Copenhagen, Department of Biomedical Sciences, The Panum Institute, 3 Blegdamsvej, Copenhagen, DK-2200 Denmark.
| | - Lærke Smidt Gasbjerg
- Department of Biomedical Sciences and the NovoNordisk Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, The Panum Institute, Copenhagen N, DK-2200 Denmark
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences and the NovoNordisk Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, The Panum Institute, Copenhagen N, DK-2200 Denmark
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11
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Yang L, Liang H, Liu X, Wang X, Cheng Y, Zhao Y, Liu L, Huang G, Wang X, Zhou Z. Islet Function and Insulin Sensitivity in Latent Autoimmune Diabetes in Adults Taking Sitagliptin: A Randomized Trial. J Clin Endocrinol Metab 2021; 106:e1529-e1541. [PMID: 33475138 PMCID: PMC7993585 DOI: 10.1210/clinem/dgab026] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Indexed: 12/17/2022]
Abstract
CONTEXT The long-term effects of dipeptidyl peptidase-4 inhibitors on β-cell function and insulin sensitivity in latent autoimmune diabetes in adults (LADA) are unclear. OBJECTIVE To investigate the effects of sitagliptin on β-cell function and insulin sensitivity in LADA patients receiving insulin. DESIGN AND SETTING A randomized controlled trial at the Second Xiangya Hospital. METHODS Fifty-one patients with LADA were randomized to sitagliptin + insulin (SITA) group or insulin alone (CONT) group for 24 months. MAIN OUTCOME MEASURES Fasting C-peptide (FCP), 2-hour postprandial C-peptide (2hCP) during mixed-meal tolerance test, △CP (2hCP - FCP), and updated homeostatic model assessment of β-cell function (HOMA2-B) were determined every 6 months. In 12 subjects, hyperglycemic clamp and hyperinsulinemic euglycemic clamp (HEC) tests were further conducted at 12-month intervals. RESULTS During the 24-month follow-up, there were no significant changes in β-cell function in the SITA group, whereas the levels of 2hCP and △CP in the CONT group were reduced at 24 months. Meanwhile, the changes in HOMA2-B from baseline were larger in the SITA group than in the CONT group. At 24 months, first-phase insulin secretion was improved in the SITA group by hyperglycemia clamp, which was higher than in the CONT group (P < .001), while glucose metabolized (M), insulin sensitivity index, and M over logarithmical insulin ratio in HEC were increased in the SITA group (all P < .01 vs baseline), which were higher than in the CONT group. CONCLUSION Compared with insulin intervention alone, sitagliptin plus insulin treatment appeared to maintain β-cell function and improve insulin sensitivity in LADA to some extent.
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Affiliation(s)
- Lin Yang
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Huiying Liang
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Affiliated Dongguan People’s Hospital, Southern Medical University (Dongguan People’s Hospital), Dongguan, Guangdong, China
| | - Xinyuan Liu
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Department of Geriatric Endocrinology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Xia Wang
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Ying Cheng
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yunjuan Zhao
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Lingjiao Liu
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Gan Huang
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Xiangbing Wang
- Division of Endocrinology, Metabolism and Nutrition, Rutgers University-Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Zhiguang Zhou
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Correspondence: Zhiguang Zhou, MD, PhD, Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, No. 139 Renmin Road, Changsha 410011, Hunan, China.
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12
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Buitinga M, Cohrs CM, Eter WA, Claessens-Joosten L, Frielink C, Bos D, Sandker G, Brom M, Speier S, Gotthardt M. Noninvasive Monitoring of Glycemia-Induced Regulation of GLP-1R Expression in Murine and Human Islets of Langerhans. Diabetes 2020; 69:2246-2252. [PMID: 32843570 DOI: 10.2337/db20-0616] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/20/2020] [Indexed: 11/13/2022]
Abstract
Glucagon-like peptide 1 receptor (GLP-1R) imaging with radiolabeled exendin has proven to be a powerful tool to quantify β-cell mass (BCM) in vivo. As GLP-1R expression is thought to be influenced by glycemic control, we examined the effect of blood glucose (BG) levels on GLP-1R-mediated exendin uptake in both murine and human islets and its implications for BCM quantification. Periods of hyperglycemia significantly reduced exendin uptake in murine and human islets, which was paralleled by a reduction in GLP-1R expression. Detailed mapping of the tracer uptake and insulin and GLP-1R expression conclusively demonstrated that the observed reduction in tracer uptake directly correlates to GLP-1R expression levels. Importantly, the linear correlation between tracer uptake and β-cell area was maintained in spite of the reduced GLP-1R expression levels. Subsequent normalization of BG levels restored absolute tracer uptake and GLP-1R expression in β-cells and the observed loss in islet volume was halted. This manuscript emphasizes the potency of nuclear imaging techniques to monitor receptor regulation noninvasively. Our findings have significant implications for clinical practice, indicating that BG levels should be near-normalized for at least 3 weeks prior to GLP-1R agonist treatment or quantitative radiolabeled exendin imaging for BCM analysis.
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Affiliation(s)
- Mijke Buitinga
- Department of Radiology and Nuclear Medicine, Radboudumc, Nijmegen, the Netherlands
- Department of Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
- Department of Nutrition and Movement Sciences, Maastricht University, Maastricht, the Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Christian M Cohrs
- Paul Langerhans Institute Dresden of Helmholtz Zentrum München at the University Clinic Carl Gustav Carus of Technische Universität Dresden, Helmholtz Zentrum München, München-Neuherberg, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
- Institute of Physiology, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Wael A Eter
- Department of Radiology and Nuclear Medicine, Radboudumc, Nijmegen, the Netherlands
| | | | - Cathelijne Frielink
- Department of Radiology and Nuclear Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Desirée Bos
- Department of Radiology and Nuclear Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Gerwin Sandker
- Department of Radiology and Nuclear Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Maarten Brom
- Department of Radiology and Nuclear Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Stephan Speier
- Paul Langerhans Institute Dresden of Helmholtz Zentrum München at the University Clinic Carl Gustav Carus of Technische Universität Dresden, Helmholtz Zentrum München, München-Neuherberg, Germany
- German Center for Diabetes Research, München-Neuherberg, Germany
- Institute of Physiology, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Martin Gotthardt
- Department of Radiology and Nuclear Medicine, Radboudumc, Nijmegen, the Netherlands
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Sandoval D. Updating the Role of α-Cell Preproglucagon Products on GLP-1 Receptor-Mediated Insulin Secretion. Diabetes 2020; 69:2238-2245. [PMID: 33082272 PMCID: PMC7576561 DOI: 10.2337/dbi19-0027] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/10/2020] [Indexed: 02/06/2023]
Abstract
While the field of islet biology has historically focused its attention on understanding β-cell function and the mechanisms by which these cells become dysfunctional with diabetes, there has been a scientific shift toward greater understanding of other endocrine cells of the islet and their paracrine role in regulating the β-cell. In recent years, many questions and new data have come forward regarding the paracrine role of the α-cell and specifically preproglucagon peptides in regulating insulin secretion. The role of intestinally secreted glucagon-like peptide 1 (GLP-1) in regulation of insulin secretion has been questioned, and a physiological role of pancreatic GLP-1 in regulation of insulin secretion has been proposed. In addition, in the last 2 years, a series of studies demonstrated a physiological role for glucagon, acting via the GLP-1 receptor, in paracrine regulation of insulin secretion. Altogether, this work challenges the textbook physiology of both GLP-1 and glucagon and presents a critical paradigm shift for the field. This article addresses these new findings surrounding α-cell preproglucagon products, with a particular focus on GLP-1, in the context of their roles in insulin secretion and consequently glucose metabolism.
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Barbot M, Regazzo D, Mondin A, Zilio M, Lizzul L, Zaninotto M, Plebani M, Arnaldi G, Ceccato F, Scaroni C. Is pasireotide-induced diabetes mellitus predictable? A pilot study on the effect of a single dose of pasireotide on glucose homeostasis. Pituitary 2020; 23:534-542. [PMID: 32524277 DOI: 10.1007/s11102-020-01055-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Pasireotide (PAS) is an effective treatment for Cushing's disease (CD) but its use is burdened by an associated high incidence of diabetes mellitus (DM). The aim of this study was to examine the effect of a single subcutaneous injection of PAS on glucose metabolism in CD, and to identify predictors of DM onset. METHODS Fifteen patients with CD (13 females, 2 males; median age 43 years [IQR 34-50]) were submitted to an acute PAS test (600 µg s.c.), measuring glucose, insulin, C-peptide, GIP, glucagon, GLP-1, ACTH, and cortisol at the baseline and every 30 min for 2 h. Then they were treated twice daily with PAS 600 µg, and followed up with clinical and hormone assessments for a median of 6 months [2-13]. RESULTS PAS prompted a significant decrease in all hormonal parameters considered except for glycemia, which increased (as expected), reaching the highest value at 120' (p < 0.0001). Overall, 9/15 patients developed DM within 2 months of starting PAS therapy. There were no differences in age, weight, visceral adiposity, HOMA index, fasting glucose or severity of CD between patients who developed DM and those who did not. Baseline fasting glucagon levels were higher in the DM patients (17.95 [12.45-20.54] vs. 10.53 [8.11-12.33] pmol/L, p = 0.0256), and so were GIP and HbA1c levels (37 [5.5-39.5] vs. 29 [27-31.8] mmol/mol, p = 0.0008). Glucose at 120' was also significantly higher in the DM patients (9.5 [8.65-11.95] vs. 6.85 [4.48-9] mmol/L, p = 0.012). CONCLUSIONS PAS was rapidly able to suppress insulin and incretin secretion, with a subsequent rise in glucose levels into the diabetic range. It also induced a significant inhibition of glucagon production. The patients at higher risk of DM during PAS therapy were those with higher glucagon levels, HbA1c > 34.5 mmol/mol, and a glucose peak after PAS administration > 9 mmol/L. CD patients with these features given PAS therapy should therefore be monitored more carefully.
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Affiliation(s)
- Mattia Barbot
- Endocrinology Unit, Department of Medicine DIMED, University-Hospital of Padova, Via Ospedale Civile 105, 35128, Padova, Italy.
| | - Daniela Regazzo
- Endocrinology Unit, Department of Medicine DIMED, University-Hospital of Padova, Via Ospedale Civile 105, 35128, Padova, Italy
| | - Alessandro Mondin
- Endocrinology Unit, Department of Medicine DIMED, University-Hospital of Padova, Via Ospedale Civile 105, 35128, Padova, Italy
| | - Marialuisa Zilio
- Endocrinology Unit, Department of Medicine DIMED, University-Hospital of Padova, Via Ospedale Civile 105, 35128, Padova, Italy
| | - Laura Lizzul
- Endocrinology Unit, Department of Medicine DIMED, University-Hospital of Padova, Via Ospedale Civile 105, 35128, Padova, Italy
| | - Martina Zaninotto
- Laboratory Medicine Unit, Department of Medicine DIMED, University-Hospital of Padova, Padova, Italy
| | - Mario Plebani
- Laboratory Medicine Unit, Department of Medicine DIMED, University-Hospital of Padova, Padova, Italy
| | - Giorgio Arnaldi
- Endocrinology Division, Department of Clinical and Molecular Sciences (DISCLIMO), Umberto I Hospital, Polytechnic University of Marche, Ancona, Italy
| | - Filippo Ceccato
- Endocrinology Unit, Department of Medicine DIMED, University-Hospital of Padova, Via Ospedale Civile 105, 35128, Padova, Italy
| | - Carla Scaroni
- Endocrinology Unit, Department of Medicine DIMED, University-Hospital of Padova, Via Ospedale Civile 105, 35128, Padova, Italy
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15
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Holst JJ, Rosenkilde MM. GIP as a Therapeutic Target in Diabetes and Obesity: Insight From Incretin Co-agonists. J Clin Endocrinol Metab 2020; 105:dgaa327. [PMID: 32459834 PMCID: PMC7308078 DOI: 10.1210/clinem/dgaa327] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/23/2020] [Indexed: 12/21/2022]
Abstract
The 2 hormones responsible for the amplification of insulin secretion after oral as opposed to intravenous nutrient administration are the gut peptides, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). However, whereas GLP-1 also inhibits appetite and food intake and improves glucose regulation in patients with type 2 diabetes (T2DM), GIP seems to be devoid of these activities, although the 2 hormones as well as their receptors are highly related. In fact, numerous studies have suggested that GIP may promote obesity. However, chimeric peptides, combining elements of both peptides and capable of activating both receptors, have recently been demonstrated to have remarkable weight-losing and glucose-lowering efficacy in obese individuals with T2DM. At the same time, antagonists of the GIP receptor have been reported to reduce weight gain/cause weight loss in experimental animals including nonhuman primates. This suggests that both agonists and antagonist of the GIP receptor should be useful, at least for weight-losing therapy. How is this possible? We here review recent experimental evidence that agonist-induced internalization of the two receptors differs markedly and that modifications of the ligand structures, as in co-agonists, profoundly influence these cellular processes and may explain that an antagonist may activate while an agonist may block receptor signaling.
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Affiliation(s)
- Jens Juul Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
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16
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Mejido DC, Peny JA, Vieira MN, Ferreira ST, De Felice FG. Insulin and leptin as potential cognitive enhancers in metabolic disorders and Alzheimer's disease. Neuropharmacology 2020; 171:108115. [DOI: 10.1016/j.neuropharm.2020.108115] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 03/30/2020] [Accepted: 04/20/2020] [Indexed: 02/08/2023]
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Nauck MA, Holle H, Kahle M, Tytko A, Deacon CF, Holst JJ, Meier JJ. No evidence of tachyphylaxis for insulinotropic actions of glucose-dependent insulinotropic polypeptide (GIP) in subjects with type 2 diabetes, their first-degree relatives, or in healthy subjects. Peptides 2020; 125:170176. [PMID: 31669136 DOI: 10.1016/j.peptides.2019.170176] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/12/2019] [Accepted: 10/14/2019] [Indexed: 01/10/2023]
Abstract
BACKGROUND, AIMS In patients with type 2 diabetes, the lost insulinotropic effect of the incretin hormone glucose-dependent insulinotropic polypeptide (GIP) is more apparent after continuous versus bolus administration. To test whether the difference might be explained by rapid tachyphylaxis in response to elevated concentrations of GIP, and whether patients with type 2 diabetes and their relatives are more susceptible to tachyphylaxis than healthy subjects. PATIENTS AND METHODS In a two-way crossover design, insulinotropic responses to repeated bolus injection (50 pmol/kg body weight at 30 and 120 min) and continuous infusion of GIP (2 pmol.kg-1.min-1 from 30 to 180 min) under hyperglycaemic clamp conditions (8.5 mmol/l) was compared in age- gender- and weight-matched patients with type 2 diabetes, first degree relatives of such patients, and healthy subjects. RESULTS Insulin secretory responses to the first and second GIP bolus were not significantly different in any of the subject groups. Subjects with type 2 diabetes had a significant relative impairment versus healthy subjects with continuous (C-peptide, -13.2 %, p < 0.05), but not with repeated bolus administration of GIP (+11.1 %, n.s.). First-degree relatives tended to hyper-secrete insulin with bolus or continuous administrations of GIP. CONCLUSIONS Rapid tachyphylaxis in response to continuous exposure to slightly supraphysiological concentrations of GIP does not explain the reduced insulinotropic response to GIP infusions in patients with type 2 diabetes or their first-degree relatives.
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Affiliation(s)
- M A Nauck
- Diabeteszentrum Bad Lauterberg, Bad Lauterberg im Harz, Germany; Diabetes Center Bochum-Hattingen, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
| | - H Holle
- Diabeteszentrum Bad Lauterberg, Bad Lauterberg im Harz, Germany
| | - M Kahle
- Diabeteszentrum Bad Lauterberg, Bad Lauterberg im Harz, Germany; Diabetes Center Bochum-Hattingen, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany
| | - A Tytko
- Diabeteszentrum Bad Lauterberg, Bad Lauterberg im Harz, Germany
| | - C F Deacon
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - J J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - J J Meier
- Diabetes Center Bochum-Hattingen, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany
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18
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Gasbjerg LS, Bergmann NC, Stensen S, Christensen MB, Rosenkilde MM, Holst JJ, Nauck M, Knop FK. Evaluation of the incretin effect in humans using GIP and GLP-1 receptor antagonists. Peptides 2020; 125:170183. [PMID: 31693916 DOI: 10.1016/j.peptides.2019.170183] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/22/2019] [Accepted: 10/24/2019] [Indexed: 02/07/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) potentiate glucose-induced insulin secretion and are therefore thought to be responsible for the incretin effect. The magnitude of the incretin effect, defined as the fraction of postprandial insulin secretion stimulated by intestinal factors, has been reported to be up to ∼60% in healthy individuals. In several pathological conditions but especially in patients with type 2 diabetes, the incretin effect is severely reduced or even absent. In line with this, the insulinotropic effects of GIP and GLP-1 are impaired in patients with type 2 diabetes, even when administered in supraphysiological doses. In healthy individuals, GIP has been proposed to be the most important incretin hormone of the two, but the individual contribution of the two is difficult to determine. However, using incretin hormone receptor antagonists: the novel GIP receptor antagonist GIP(3-30)NH2 and the widely used GLP-1 receptor antagonist exendin(9-39)NH2, we can now distinguish between the effects of the two hormones. In this review, we present and discuss studies in which the individual contribution of GIP and GLP-1 to the incretin effect in healthy individuals have been estimated and discuss the limitations of using incretin hormone receptor antagonists.
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Affiliation(s)
- Lærke S Gasbjerg
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Natasha C Bergmann
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Signe Stensen
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Mikkel B Christensen
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Pharmacology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Nauck
- Diabetes Division, St. Josef Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Filip K Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Steno Diabetes Center Copenhagen, Gentofte, Denmark
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Abstract
PURPOSE OF REVIEW Among the gastrointestinal hormones, the incretins: glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 have attracted interest because of their importance for the development and therapy of type 2 diabetes and obesity. New agonists and formulations of particularly the GLP-1 receptor have been developed recently showing great therapeutic efficacy for both diseases. RECENT FINDINGS The status of the currently available GLP-1 receptor agonists (GLP-1RAs) is described, and their strengths and weaknesses analyzed. Their ability to also reduce cardiovascular and renal risk is described and analysed. The most recent development of orally available agonists and of very potent monomolecular co-agonists for both the GLP-1 and GIP receptor is also discussed. SUMMARY The GLP-1RAs are currently the most efficacious agents for weight loss, and show potential for further efficacy in combination with other food-intake-regulating peptides. Because of their glycemic efficacy and cardiorenal protection, the GLP-1 RAs will be prominent elements in future diabetes therapy.
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Affiliation(s)
- Jens Juul Holst
- NNF Center for Basic Metabolic Research and Department of Biomedical Sciences, The Panum Institute, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, Copenhagen N, Denmark
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20
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Salehi M, Gastaldelli A, D'Alessio DA. Beta-cell sensitivity to insulinotropic gut hormones is reduced after gastric bypass surgery. Gut 2019; 68:1838-1845. [PMID: 30772836 DOI: 10.1136/gutjnl-2018-317760] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 01/14/2019] [Accepted: 01/15/2019] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Postprandial hyperinsulinaemia after Roux-en Y gastric bypass (GB) has been attributed to rapid nutrient flux from the gut, and an enhanced incretin effect. However, it is unclear whether surgery changes islet cell responsiveness to regulatory factors. This study tested the hypothesis that β-cell sensitivity to glucagon like-peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) is attenuated after GB. DESIGN Ten non-diabetic subjects with GB, and 9 body mass index (BMI)-matched and age-matched non-surgical controls (CN) with normal glucose tolerance had blood glucose clamped at ~7.8 mM on three separate days. Stepwise incremental infusions of GLP-1 (15, 30, 60, 120 and 300 ng/LBkg/h), GIP (75, 150, 300, 600 and 1200 ng/LBkg/h) or saline were administered from 90 to 240 min and insulin secretion measured. RESULTS GB subjects had similar fasting glucose levels but lower fasting insulin compared with CN, likely due to increased insulin clearance. The average insulin secretion rates (ISRs) to 7.8 mM glucose were ~30% lower in GB relative to CN subjects. However, incretin-stimulated ISRs, adjusted for insulin sensitivity and glucose-stimulated insulin secretion, were even more attenuated in the GB subjects, by threefold to fourfold (AUCISR(90-240 min) during GLP-1 and GIP: 47±8 and 44±12 nmol in GB and 116±16 and 161±44 in CN; p<0.01). CONCLUSION After GB, the sensitivity of insulin secretion to both glucose and incretins is diminished.
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Affiliation(s)
- Marzieh Salehi
- Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Department of Medicine, University of Texas at San Antonio, San Antonio, Texas, USA.,Bartter Research Unit, South Texas Veterans Health Care System, Audie Murphy Hospital, San Antonio, Texas, USA
| | - Amalia Gastaldelli
- Cardiometabolic Risk Unit, CNR Institute of Clinical Physiology, Pisa, Italy
| | - David A D'Alessio
- Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
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Holst JJ. From the Incretin Concept and the Discovery of GLP-1 to Today's Diabetes Therapy. Front Endocrinol (Lausanne) 2019; 10:260. [PMID: 31080438 PMCID: PMC6497767 DOI: 10.3389/fendo.2019.00260] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/08/2019] [Indexed: 12/24/2022] Open
Abstract
Researchers have been looking for insulin-stimulating factors for more than 100 years, and in the 1960ties it was definitively proven that the gastrointestinal tract releases important insulinotropic factors upon oral glucose intake, so-called incretin hormones. The first significant factor identified was the duodenal glucose-dependent insulinotropic polypeptide, GIP, which however, turned out not to stimulate insulin secretion in patients with type 2 diabetes. But resection experiments clearly indicated the presence of an additional incretin, and in 1986, an unexpected processing fragment of the recently identified glucagon precursor, proglucagon, namely truncated glucagon-like peptide 1 (GLP-1 7-36 amide), was isolated from the gut and found to both stimulate insulin secretion and inhibit glucagon secretion. The peptide also inhibited appetite and food intake. Unlike GIP, this peptide had preserved effects in patients with type 2 diabetes and it was soon documented to have powerful antidiabetic effects in clinical studies. Its utility was limited, however, because of an extremely short half-life in humans, but this problem had two solutions, both of which gave rise to important antidiabetic drugs: (1) orally active inhibitors of the enzyme dipeptidylpeptidase 4 (DPP-4 inhibitors), which was responsible for the rapid degradation; the inhibitors protect endogenous GLP-1 from degradation and thereby unfold its antidiabetic activity, and (2) long-acting injectable analogs of GLP-1 protected against DPP-4 degradation. Particularly, the latter, the GLP-1 receptor agonists, either alone or in various combinations, are so powerful that treatment allows more than 2/3 of type 2 diabetes patients to reach glycemic targets. In addition, these agents cause a weight loss which, with the most successful compounds, may exceed 10% of body weight. Most recently they have also been shown to be renoprotective and reduce cardiovascular risk and mortality.
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Coskun T, Sloop KW, Loghin C, Alsina-Fernandez J, Urva S, Bokvist KB, Cui X, Briere DA, Cabrera O, Roell WC, Kuchibhotla U, Moyers JS, Benson CT, Gimeno RE, D'Alessio DA, Haupt A. LY3298176, a novel dual GIP and GLP-1 receptor agonist for the treatment of type 2 diabetes mellitus: From discovery to clinical proof of concept. Mol Metab 2018; 18:3-14. [PMID: 30473097 PMCID: PMC6308032 DOI: 10.1016/j.molmet.2018.09.009] [Citation(s) in RCA: 367] [Impact Index Per Article: 61.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 09/26/2018] [Accepted: 09/28/2018] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE A novel dual GIP and GLP-1 receptor agonist, LY3298176, was developed to determine whether the metabolic action of GIP adds to the established clinical benefits of selective GLP-1 receptor agonists in type 2 diabetes mellitus (T2DM). METHODS LY3298176 is a fatty acid modified peptide with dual GIP and GLP-1 receptor agonist activity designed for once-weekly subcutaneous administration. LY3298176 was characterised in vitro, using signaling and functional assays in cell lines expressing recombinant or endogenous incretin receptors, and in vivo using body weight, food intake, insulin secretion and glycemic profiles in mice. A Phase 1, randomised, placebo-controlled, double-blind study was comprised of three parts: a single-ascending dose (SAD; doses 0.25-8 mg) and 4-week multiple-ascending dose (MAD; doses 0.5-10 mg) studies in healthy subjects (HS), followed by a 4-week multiple-dose Phase 1 b proof-of-concept (POC; doses 0.5-15 mg) in patients with T2DM (ClinicalTrials.gov no. NCT02759107). Doses higher than 5 mg were attained by titration, dulaglutide (DU) was used as a positive control. The primary objective was to investigate safety and tolerability of LY3298176. RESULTS LY3298176 activated both GIP and GLP-1 receptor signaling in vitro and showed glucose-dependent insulin secretion and improved glucose tolerance by acting on both GIP and GLP-1 receptors in mice. With chronic administration to mice, LY3298176 potently decreased body weight and food intake; these effects were significantly greater than the effects of a GLP-1 receptor agonist. A total of 142 human subjects received at least 1 dose of LY3298176, dulaglutide, or placebo. The PK profile of LY3298176 was investigated over a wide dose range (0.25-15 mg) and supports once-weekly administration. In the Phase 1 b trial of diabetic subjects, LY3298176 doses of 10 mg and 15 mg significantly reduced fasting serum glucose compared to placebo (least square mean [LSM] difference [95% CI]: -49.12 mg/dL [-78.14, -20.12] and -43.15 mg/dL [-73.06, -13.21], respectively). Reductions in body weight were significantly greater with the LY3298176 1.5 mg, 4.5 mg and 10 mg doses versus placebo in MAD HS (LSM difference [95% CI]: -1.75 kg [-3.38, -0.12], -5.09 kg [-6.72, -3.46] and -4.61 kg [-6.21, -3.01], respectively) and doses of 10 mg and 15 mg had a relevant effect in T2DM patients (LSM difference [95% CI]: -2.62 kg [-3.79, -1.45] and -2.07 kg [-3.25, -0.88], respectively. The most frequent side effects reported with LY3298176 were gastrointestinal (vomiting, nausea, decreased appetite, diarrhoea, and abdominal distension) in both HS and patients with T2DM; all were dose-dependent and considered mild to moderate in severity. CONCLUSIONS Based on these results, the pharmacology of LY3298176 translates from preclinical to clinical studies. LY3298176 has the potential to deliver clinically meaningful improvement in glycaemic control and body weight. The data warrant further clinical evaluation of LY3298176 for the treatment of T2DM and potentially obesity.
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Affiliation(s)
- Tamer Coskun
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Kyle W Sloop
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Corina Loghin
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | | | - Shweta Urva
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Krister B Bokvist
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Xuewei Cui
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Daniel A Briere
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Over Cabrera
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - William C Roell
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Uma Kuchibhotla
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Julie S Moyers
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Charles T Benson
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Ruth E Gimeno
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - David A D'Alessio
- Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC, USA
| | - Axel Haupt
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA.
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Choi H, Kramer CK, Zinman B, Connelly PW, Retnakaran R. Effect of short-term intensive insulin therapy on the incretin response in early type 2 diabetes. DIABETES & METABOLISM 2018; 45:197-200. [PMID: 29395808 DOI: 10.1016/j.diabet.2018.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/04/2017] [Accepted: 01/03/2018] [Indexed: 01/07/2023]
Abstract
AIMS Short-term intensive insulin therapy (IIT) and gastric bypass surgery are both interventions that can improve beta-cell function, reduce insulin resistance and induce remission of type 2 diabetes. Whereas gastric bypass yields an enhanced glucagon-like peptide-1 (GLP-1) response that may contribute to its metabolic benefits, the effect of short-term IIT on the incretin response is unclear. Thus, we sought to evaluate the impact of IIT on GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) secretion in early type 2 diabetes. METHODS In this study, 63 patients (age 59±8.3 years, baseline A1c 6.8±0.7%, diabetes duration 3.0±2.1 years) underwent 4 weeks of IIT (basal insulin detemir and pre-meal insulin aspart). GLP-1, GIP and glucagon responses were assessed by the area-under-the-curve (AUC) of these hormones on oral glucose tolerance tests at baseline and 1-day after the completion of therapy. Beta-cell function was assessed by Insulin Secretion-Sensitivity Index-2 (ISSI-2), with insulin resistance measured by Homeostasis Model Assessment (HOMA-IR). RESULTS As expected, comparing the post-therapy oral glucose tolerance test to that at baseline, IIT increased ISSI-2 (P=0.02), decreased HOMA-IR (P<0.001), and reduced AUCglucagon (P<0.001). Of note, however, IIT had no significant impact on AUCGLP-1 (P=0.24) and reduced AUCGIP (P=0.02). CONCLUSION Despite improving beta-cell function, insulin resistance and glucagonemia, short-term IIT does not change GLP-1 secretion and decreases the GIP response to an oral glucose challenge in early type 2 diabetes. Thus, the beneficial impact of this therapy on glucose homeostasis is not attributable to its effects on incretin secretion.
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Affiliation(s)
- H Choi
- Leadership Sinai center for diabetes, Mount Sinai hospital, Toronto, Canada
| | - C K Kramer
- Leadership Sinai center for diabetes, Mount Sinai hospital, Toronto, Canada; Division of endocrinology, university of Toronto, Toronto, Canada
| | - B Zinman
- Leadership Sinai center for diabetes, Mount Sinai hospital, Toronto, Canada; Division of endocrinology, university of Toronto, Toronto, Canada; Lunenfeld-Tanenbaum research institute, Mount Sinai hospital, Toronto, Canada
| | - P W Connelly
- Division of endocrinology, university of Toronto, Toronto, Canada; Keenan research center for biomedical science of St. Michael's hospital, Toronto, Canada; Department of laboratory medicine and pathobiology, university of Toronto, Toronto, Canada
| | - R Retnakaran
- Leadership Sinai center for diabetes, Mount Sinai hospital, Toronto, Canada; Division of endocrinology, university of Toronto, Toronto, Canada; Lunenfeld-Tanenbaum research institute, Mount Sinai hospital, Toronto, Canada.
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24
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Mandøe MJ, Hansen KB, Windeløv JA, Knop FK, Rehfeld JF, Rosenkilde MM, Holst JJ, Hansen HS. Comparing olive oil and C4-dietary oil, a prodrug for the GPR119 agonist, 2-oleoyl glycerol, less energy intake of the latter is needed to stimulate incretin hormone secretion in overweight subjects with type 2 diabetes. Nutr Diabetes 2018; 8:2. [PMID: 29330461 PMCID: PMC6199285 DOI: 10.1038/s41387-017-0011-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 08/01/2017] [Accepted: 11/06/2017] [Indexed: 02/08/2023] Open
Abstract
Background/objective After digestion, dietary triacylglycerol stimulates incretin release in humans, mainly through generation of 2-monoacylglycerol, an agonist for the intestinal G protein-coupled receptor 119 (GPR119). Enhanced incretin release may have beneficial metabolic effects. However, dietary fat may promote weight gain and should therefore be restricted in obesity. We designed C4-dietary oil (1,3-di-butyryl-2-oleoyl glycerol) as a 2-oleoyl glycerol (2-OG)-generating fat type, which would stimulate incretin release to the same extent while providing less calories than equimolar amounts of common triglycerides, e.g., olive oil. Subjects and methods We studied the effect over 180 min of (a) 19 g olive oil plus 200 g carrot, (b) 10.7 g C4 dietary oil plus 200 g carrot and (c) 200 g carrot, respectively, on plasma responses of gut and pancreatic hormones in 13 overweight patients with type 2 diabetes (T2D). Theoretically, both oil meals result in formation of 7.7 g 2-OG during digestion. Results Both olive oil and C4-dietary oil resulted in greater postprandial (P ≤ 0.01) glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) responses (incremental area under curve (iAUC)): iAUCGLP−1: 645 ± 194 and 702 ± 97 pM × min; iAUCGIP: 4,338 ± 764 and 2,894 ± 601 pM × min) compared to the carrot meal (iAUCGLP−1: 7 ± 103 pM × min; iAUCGIP: 266 ± 234 pM × min). iAUC for GLP-1 and GIP were similar for C4-dietary oil and olive oil, although olive oil resulted in a higher peak value for GIP than C4-dietary oil. Conclusion C4-dietary oil enhanced secretion of GLP-1 and GIP to almost the same extent as olive oil, in spite of liberation of both 2-OG and oleic acid, which also may stimulate incretin secretion, from olive oil. Thus, C4-dietary oil is more effective as incretin releaser than olive oil per unit of energy and may be useful for dietary intervention.
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Affiliation(s)
- Mette Johannsen Mandøe
- The Novo Nordisk Foundation Center for Basal Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Physiology and Nuclear Medicine, Glostrup Hospital, University of Copenhagen, Glostrup, Denmark
| | - Katrine Bagge Hansen
- The Novo Nordisk Foundation Center for Basal Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Physiology and Nuclear Medicine, Glostrup Hospital, University of Copenhagen, Glostrup, Denmark
| | - Johanne Agerlin Windeløv
- The Novo Nordisk Foundation Center for Basal Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip Krag Knop
- The Novo Nordisk Foundation Center for Basal Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Frederik Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Mette Marie Rosenkilde
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- The Novo Nordisk Foundation Center for Basal Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. .,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Harald Severin Hansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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25
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Tura A, Bagger JI, Ferrannini E, Holst JJ, Knop FK, Vilsbøll T, Mari A. Impaired beta cell sensitivity to incretins in type 2 diabetes is insufficiently compensated by higher incretin response. Nutr Metab Cardiovasc Dis 2017; 27:1123-1129. [PMID: 29162361 DOI: 10.1016/j.numecd.2017.10.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/15/2017] [Accepted: 10/05/2017] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND AIMS The incretin effect is impaired in type 2 diabetes (T2D), but the underlying mechanisms are only partially understood. We investigated the relationships between the time course of the incretin effect and that of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) during oral glucose tolerance tests (OGTTs), thereby estimating incretin sensitivity of the beta cell, and its associated factors. METHODS AND RESULTS Eight patients with T2D and eight matched subjects with normal glucose tolerance (NGT) received 25, 75, and 125 g OGTTs and corresponding isoglycemic glucose infusions (IIGI). The time course of the incretin effect, representing potentiation of insulin secretion by incretins (PINCR), was determined by mathematical modelling as the time-dependent fold increase in insulin secretion during OGTT compared to IIGI. The time course of PINCR was correlated with that of both GIP and GLP-1 in each subject (median r = 0.67 in NGT and 0.45 in T2D). We calculated an individual beta cell sensitivity to incretins (SINCR) using a weighted average of GIP and GLP-1 (pooled incretin concentration, PIC), as the slope of the relationship between PINCR and PIC. SINCR was reduced in T2D (p < 0.01). In the whole group, mean PIC, GIP and GLP-1 concentrations during the OGTT were inversely correlated with SINCR, but T2D had lower PIC, GIP and GLP-1 levels at the same SINCR (p < 0.05). CONCLUSION Relative incretin insensitivity is partly compensated for by higher incretin secretory responses. However, T2D shows both impairment in incretin sensitivity and abnormal compensation by incretin secretion.
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Affiliation(s)
- A Tura
- CNR Institute of Neuroscience, Padova, Italy
| | - J I Bagger
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - E Ferrannini
- Department of Internal Medicine, University of Pisa School of Medicine, Pisa, Italy; CNR Institute of Clinical Physiology, Pisa, Italy
| | - J J Holst
- The NNF Center for Basic Metabolic Research, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - F K Knop
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; The NNF Center for Basic Metabolic Research, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - T Vilsbøll
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - A Mari
- CNR Institute of Neuroscience, Padova, Italy.
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26
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Okwudili OS, Chimaobi NG, Ikechukwu EM, Ndukaku OY. Antidiabetic and in vitro antioxidant effects of hydromethanol extract of Paullinia pinnata root bark in alloxan-induced diabetic rat. JOURNAL OF COMPLEMENTARY & INTEGRATIVE MEDICINE 2017; 15:/j/jcim.ahead-of-print/jcim-2015-0017/jcim-2015-0017.xml. [PMID: 29148978 DOI: 10.1515/jcim-2015-0017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 10/02/2017] [Indexed: 11/15/2022]
Abstract
Background The study evaluated phytochemical composition, antidiabetic, oral glucose tolerance test and in vitro antioxidant activities of hydromethanol extract of Paullinia pinnata root bark. Methods Cold maceration method was used in extract preparation and scavenging of 2,2-diphenyl-1-picrylhydrazyl radicals was used to evaluate antioxidant properties of the extract. Diabetes was induced with alloxan at the dose of 160 mg/kg. The antidiabetic activity of the extract was tested at doses of 50, 100 and 200 mg/kg, and glibenclamide was used as reference drug. Results Phytochemical analysis of the extract showed the presence of alkaloids, flavonoids, glycosides, tannins, saponins and terpenes/sterols. The extract produced a significant (p<0.05) time-dependent decrease in the fasting blood glucose (FBG) levels in the treated rats when compared with the distilled water treated rats, but did not produce dose-dependent effects. The extract 50, 100 and 200 mg/kg and glibenclamide (2 mg/kg) caused 83.62 %, 60.66 %, 47.77 % and 68.52 % reduction respectively in FBG at 6 h post-treatment while the distilled water (5 mL/kg) produced 8.12 % reduction in FBG at 6 h post treatment. The extract (50 mg/kg) and glibenclamide (2 mg/kg) produced a significant (p<0.05) oral glucose tolerance effect in both normoglycemic and diabetic rats. The extract produced concentration-dependent increase in antioxidant activity and had its optimum effect at 400 µg/mL concentration. Conclusions This study suggests that P. pinnata root bark has potent antidiabetic and antioxidant activities and also validates its use in folkloric medicine in the management of diabetes-related conditions.
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Affiliation(s)
- Onoja Samuel Okwudili
- Department of Veterinary Physiology, Michael Okpara University of Agriculture Umudike, Pharmacology, Biochemistry and Animal Health and Production, College of Veterinary Medicine, PMB 7267, Abia State Umuahia, Nigeria
- Department of Biochemistry, Michael Okpara University of Agriculture, College of Natural Sciences, PMB 7267, Abia State Umuahia, Nigeria
| | - Nwachukwu Glory Chimaobi
- Department of Biochemistry, Michael Okpara University of Agriculture, College of Natural Sciences, PMB 7267, Abia State Umuahia, Nigeria
| | - Ezeja Maxwell Ikechukwu
- Department of Veterinary Physiology, Michael Okpara University of Agriculture Umudike, Pharmacology, Biochemistry and Animal Health and Production, College of Veterinary Medicine, PMB 7267, Abia State Umuahia, Nigeria
| | - Omeh Yusuf Ndukaku
- Department of Biochemistry, Michael Okpara University of Agriculture, College of Natural Sciences, PMB 7267, Abia State Umuahia, Nigeria
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27
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Holst JJ, Pedersen J, Wewer Albrechtsen NJ, Knop FK. The Gut: A Key to the Pathogenesis of Type 2 Diabetes? Metab Syndr Relat Disord 2017; 15:259-262. [PMID: 28605280 DOI: 10.1089/met.2017.0015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In this communication we discuss the role of the gut for the development of type 2 diabetes mellitus (T2DM). Gastric emptying rates importantly determine postprandial glucose excursions and regulate postprandial secretion of the incretin hormones, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-1 (GLP-1). It thereby also determines their powerful, amplifying effect on glucose-induced insulin secretion and thus the ability of the body to regulate glucose disposal. Although disturbances in gastric emptying are not consistent findings in type 2 diabetes, the incretin system is seriously impaired, probably associated with insulin resistance and obesity. Both of the incretin hormones lose (part of) their insulinotropic activity resulting, together with (genetically) defective beta cell function, in the impaired postprandial insulin secretion of T2DM. In addition, glucagon responses are inappropriately increased and importantly contribute to both fasting and postprandial hyperglycemia. This may involve stimulation by GIP, but evidence also points to a role of circulating amino acids, which are elevated due to steatosis-induced impaired glucagon-mediated hepatic clearance, in line with recent work suggesting that the alpha cells and the liver are linked in a close, amino acid-mediated feedback circuit. Thus, the gut plays an important role in the development of T2DM spurred by overeating and defective beta cells.
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Affiliation(s)
- Jens Juul Holst
- 1 Department of Biomedical Sciences, Faculty of Health and Medical Sciences, NNF Center for Basic Metabolic Research, University of Copenhagen , Copenhagen, Denmark
| | - Jens Pedersen
- 1 Department of Biomedical Sciences, Faculty of Health and Medical Sciences, NNF Center for Basic Metabolic Research, University of Copenhagen , Copenhagen, Denmark
| | - Nicolai Jacob Wewer Albrechtsen
- 1 Department of Biomedical Sciences, Faculty of Health and Medical Sciences, NNF Center for Basic Metabolic Research, University of Copenhagen , Copenhagen, Denmark
| | - Filip Krag Knop
- 2 Center for Diabetes Research, Gentofte Hospital, University of Copenhagen , Copenhagen, Denmark
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28
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Roussel M, Mathieu J, Dalle S. Molecular mechanisms redirecting the GLP-1 receptor signalling profile in pancreatic β-cells during type 2 diabetes. Horm Mol Biol Clin Investig 2017; 26:87-95. [PMID: 26953712 DOI: 10.1515/hmbci-2015-0071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 01/24/2016] [Indexed: 02/06/2023]
Abstract
Treatments with β-cell preserving properties are essential for the management of type 2 diabetes (T2D), and the new therapeutic avenues, developed over the last years, rely on the physiological role of glucagon-like peptide-1 (GLP-1). Sustained pharmacological levels of GLP-1 are achieved by subcutaneous administration of GLP-1 analogues, while transient and lower physiological levels of GLP-1 are attained following treatment with inhibitors of dipeptidylpeptidase 4 (DPP4), an endoprotease which degrades the peptide. Both therapeutic classes display a sustained and durable hypoglycaemic action in patients with T2D. However, the GLP-1 incretin effect is known to be reduced in patients with T2D, and GLP-1 analogues and DPP4 inhibitors were shown to lose their effectiveness over time in some patients. The pathological mechanisms behind these observations can be either a decrease in GLP-1 secretion from intestinal L-cells and, as a consequence, a reduction in GLP-1 plasma concentrations, combined or not with a reduced action of GLP-1 in the β-cell, the so-called GLP-1 resistance. Much evidence for a GLP-1 resistance of the β-cell in subjects with T2D have emerged. Here, we review the potential roles of the genetic background, the hyperglycaemia, the hyperlipidaemia, the prostaglandin E receptor 3, the nuclear glucocorticoid receptor, the GLP-1R desensitization and internalisation processes, and the β-arrestin-1 expression levels on GLP-1 resistance in β-cells during T2D.
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Muscogiuri G, DeFronzo RA, Gastaldelli A, Holst JJ. Glucagon-like Peptide-1 and the Central/Peripheral Nervous System: Crosstalk in Diabetes. Trends Endocrinol Metab 2017; 28:88-103. [PMID: 27871675 DOI: 10.1016/j.tem.2016.10.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/30/2016] [Accepted: 10/03/2016] [Indexed: 12/17/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is released in response to meals and exerts important roles in the maintenance of normal glucose homeostasis. GLP-1 is also important in the regulation of neurologic and cognitive functions. These actions are mediated via neurons in the nucleus of the solitary tract that project to multiple regions expressing GLP-1 receptors (GLP-1Rs). Treatment with GLP-1R agonists (GLP-1-RAs) reduces ischemia-induced hyperactivity, oxidative stress, neuronal damage and apoptosis, cerebral infarct volume, and neurologic damage, after cerebral ischemia, in experimental models. Ongoing human trials report a neuroprotective effect of GLP-1-RAs in Alzheimer's and Parkinson's disease. In this review, we discuss the role of GLP-1 and GLP-1-RAs in the nervous system with focus on GLP-1 actions on appetite regulation, glucose homeostasis, and neuroprotection.
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Affiliation(s)
| | - Ralph A DeFronzo
- Diabetes Division, University of Texas Health Science Center, San Antonio, TX, USA
| | - Amalia Gastaldelli
- Diabetes Division, University of Texas Health Science Center, San Antonio, TX, USA; Institute of Clinical Physiology of the National Research Council (CNR), Pisa, Italy.
| | - Jens J Holst
- NNF Center for Basic Metabolic Research and Department of Biomedical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
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30
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Shimoda M, Miyoshi-Takai M, Irie S, Tanabe A, Obata A, Okauchi S, Hirukawa H, Kimura T, Kohara K, Kamei S, Mune T, Kaku K, Kaneto H. Inadequate Triglyceride Management Worsens the Durability of Dipeptidyl Peptidase-4 Inhibitor in Subjects with Type 2 Diabetes Mellitus. J Diabetes Res 2017; 2017:5856475. [PMID: 28626771 PMCID: PMC5463141 DOI: 10.1155/2017/5856475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Dipeptidyl peptidase-4 (DPP-4) inhibitors are often used all over the world and exert various beneficial effects including glucose-lowering effect in many subjects with type 2 diabetes. It is poorly understood, however, which factors are closely related with the durability of glucose-lowering effect by DPP-4 inhibitor. In this study, we examined retrospectively which factors could mainly influence the durability of DPP-4 inhibitor. We enrolled 212 participants with type 2 diabetes to whom DPP-4 inhibitor was administered for over 1 year without an addition or increase of other hypoglycemic agents. Age and baseline HbA1c level were significantly higher in the effective group than those in the ineffective group. The effective group had a tendency of smaller amounts of weight change, average total cholesterol, and average triglyceride compared with the ineffective group. Multiple logistic regression analysis showed that average triglyceride and baseline HbA1c were independent predictors associated with the durability of DPP-4 inhibitor. Moreover, an average triglyceride level contributed to the durability of DPP-4 inhibitor in the obese group (BMI ≥ 25 kg/m2) but not in the nonobese group (BMI < 25 kg/m2). These results suggest the importance of strict triglyceride management to maintain the durability of glucose-lowering effect by DPP-4 inhibitor, especially in obese subjects with type 2 diabetes.
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Affiliation(s)
- Masashi Shimoda
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
- *Masashi Shimoda:
| | - Maiko Miyoshi-Takai
- Division of General Internal Medicine 1, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Shintaro Irie
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Akihito Tanabe
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Atsushi Obata
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Seizo Okauchi
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Hidenori Hirukawa
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Tomohiko Kimura
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Kenji Kohara
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Shinji Kamei
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Tomoatsu Mune
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Kohei Kaku
- Division of General Internal Medicine 1, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
| | - Hideaki Kaneto
- Division of Diabetes, Metabolism and Endocrinology, Kawasaki Medical School, 577 Matsushima, Kurashiki 701-0192, Japan
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Skow MA, Bergmann NC, Knop FK. Diabetes and obesity treatment based on dual incretin receptor activation: 'twincretins'. Diabetes Obes Metab 2016; 18:847-54. [PMID: 27160961 DOI: 10.1111/dom.12685] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 03/30/2016] [Accepted: 04/30/2016] [Indexed: 12/18/2022]
Abstract
The gut incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are secreted after meal ingestion and work in concert to promote postprandial insulin secretion and regulate glucagon secretion. GLP-1 also slows gastric emptying and suppresses appetite, whereas GIP seems to affect lipid metabolism. The introduction of selective GLP-1 receptor (GLP-1R) agonists for the treatment of type 2 diabetes and obesity has increased the scientific and clinical interest in incretins. Combining the body weight-lowering and glucose-lowering effects of GLP-1 with a more potent improvement of β cell function through additional GIP action could potentially offer a more effective treatment of diabetes and obesity, with fewer adverse effects than selective GLP-1R agonists; therefore, new drugs designed to co-activate both the GIP receptor (GIPR) and the GLP-1R simultaneously are under development. In the present review, we address advances in the field of GIPR and GLP-1R co-agonism and review in vitro studies, animal studies and human trials involving co-administration of the two incretins, as well as results from a recently developed GIPR/GLP-1R co-agonist, and highlight promising areas and challenges within the field of incretin dual agonists.
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Affiliation(s)
- M A Skow
- Centre for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - N C Bergmann
- Centre for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - F K Knop
- Centre for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Department of Biomedical Sciences and NNF Centre for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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32
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Holst JJ, Windeløv JA, Boer GA, Pedersen J, Svendsen B, Christensen M, Torekov S, Asmar M, Hartmann B, Nissen A. Searching for the physiological role of glucose-dependent insulinotropic polypeptide. J Diabetes Investig 2016; 7 Suppl 1:8-12. [PMID: 27186349 PMCID: PMC4854498 DOI: 10.1111/jdi.12488] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/21/2016] [Indexed: 01/27/2023] Open
Abstract
Glucose‐dependent insulinotropic polypeptide (GIP) was established as a gut hormone more than 40 years ago, and there is good experimental support for its role as an incretin hormone although deletion of the GIP receptor or the GIP cells or GIP receptor mutations have only minor effects on glucose metabolism. Unlike the related hormone, GLP‐1, GIP stimulates the secretion of glucagon, which in healthy individuals may help to stabilize glucose levels, but in people with type 2 diabetes may contribute to glucose intolerance. A role in lipid metabolism is supported by numerous indirect observations and by resistance to diet‐induced obesity after deletion of the GIP receptor. However, a clear effect on lipid clearance could not be identified in humans, raising doubt about its importance. The GIP receptor is widely expressed in the body and also appears to be expressed on bone cells, and experimental studies in rodent point to effects on bone metabolism. Recent studies revealed pronounced inhibitory effects of GIP on bone resorption markers in humans and suggest that GIP may be (one of the) gastrointestinal regulators of bone turn‐over. In support of this, a loss‐of‐function GIP receptor mutation in humans is associated with a marked increase in fracture risk. The lack of a reliable GIP receptor antagonist contributes to the uncertainty regarding the physiological role of GIP.
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Affiliation(s)
- Jens Juul Holst
- The NNF Center for Basic Metabolic ResearchCopnehagenDenmark; Department of Biomedical SciencesThe Panum InstituteUniversity of CopenhagenCopnehagenDenmark
| | - Johanne Agerlin Windeløv
- The NNF Center for Basic Metabolic ResearchCopnehagenDenmark; Department of Biomedical SciencesThe Panum InstituteUniversity of CopenhagenCopnehagenDenmark
| | - Geke Aline Boer
- The NNF Center for Basic Metabolic ResearchCopnehagenDenmark; Department of Biomedical SciencesThe Panum InstituteUniversity of CopenhagenCopnehagenDenmark
| | - Jens Pedersen
- The NNF Center for Basic Metabolic ResearchCopnehagenDenmark; Department of Biomedical SciencesThe Panum InstituteUniversity of CopenhagenCopnehagenDenmark
| | - Berit Svendsen
- The NNF Center for Basic Metabolic ResearchCopnehagenDenmark; Department of Biomedical SciencesThe Panum InstituteUniversity of CopenhagenCopnehagenDenmark
| | - Mikkel Christensen
- The NNF Center for Basic Metabolic ResearchCopnehagenDenmark; Department of Biomedical SciencesThe Panum InstituteUniversity of CopenhagenCopnehagenDenmark
| | - Signe Torekov
- The NNF Center for Basic Metabolic ResearchCopnehagenDenmark; Department of Biomedical SciencesThe Panum InstituteUniversity of CopenhagenCopnehagenDenmark
| | - Meena Asmar
- The NNF Center for Basic Metabolic ResearchCopnehagenDenmark; Department of Biomedical SciencesThe Panum InstituteUniversity of CopenhagenCopnehagenDenmark
| | - Bolette Hartmann
- The NNF Center for Basic Metabolic ResearchCopnehagenDenmark; Department of Biomedical SciencesThe Panum InstituteUniversity of CopenhagenCopnehagenDenmark
| | - Anne Nissen
- The NNF Center for Basic Metabolic ResearchCopnehagenDenmark; Department of Biomedical SciencesThe Panum InstituteUniversity of CopenhagenCopnehagenDenmark
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Suzuki T, Takahashi K, Fujiwara D, Shii M, Takekawa S, Matsuoka T. A reliable serum C-peptide index for the selection of an insulin regimen to achieve good glycemic control in obese patients with type 2 diabetes: an analysis from a short-term study with intensive insulin therapy. Diabetol Int 2015; 7:235-243. [PMID: 30603269 DOI: 10.1007/s13340-015-0239-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 09/16/2015] [Indexed: 11/30/2022]
Abstract
Insulin regimens achieving favorable glycemic control in patients with type 2 diabetes are expected to closely relate to residual insulin secretory ability. We herein attempted to identify a reliable C-peptide immunoreactivity (CPR) index as an insulin secretory marker that would contribute to the selection of an appropriate insulin regimen for patients with type 2 diabetes. We near-normalized blood glucose in 246 obese patients with type 2 diabetes using our protocol (which included short-term intensive insulin therapy, IIT), and administered an oral hypoglycemic agent (OHA). Based on responsiveness to OHA, patients were classified into three therapy groups: non-insulin therapy (n = 78), basal-insulin supported oral therapy (BOT) (n = 109), and multiple daily insulin injection (MDI) therapy (n = 59). Glucagon-loading CPR increment (ΔCPR), fasting CPR (FCPR), CPR2h after breakfast (CPR2h), ratio of FCPR to fasting plasma glucose (CPI), CPI2h after breakfast (CPI2h), and secretory unit of islets in transplantation (SUIT) were assessed with receiver operating characteristic (ROC) and multiple logistic analyses to discriminate the MDI group from the other therapy groups. ROC analysis revealed that CPR2h had the greatest area under the curve and specificity. Multiple logistic analysis identified CPR2h and CPI2h as the most significant explanatory variables for identifying patients assigned to the MDI group. A postprandial serum CPR marker such as CPR2h or CPI2h was shown to be the best index for predicting an appropriate insulin regimen to achieve good glycemic control in obese patients with type 2 diabetes.
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Affiliation(s)
- Takahiro Suzuki
- Diabetes Division, Department of Internal Medicine, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama 710-8602 Japan
| | - Kenji Takahashi
- Diabetes Division, Department of Internal Medicine, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama 710-8602 Japan
| | - Daisuke Fujiwara
- Diabetes Division, Department of Internal Medicine, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama 710-8602 Japan
| | - Masakazu Shii
- Diabetes Division, Department of Internal Medicine, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama 710-8602 Japan
| | - Sato Takekawa
- Diabetes Division, Department of Internal Medicine, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama 710-8602 Japan
| | - Takashi Matsuoka
- Diabetes Division, Department of Internal Medicine, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama 710-8602 Japan
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Haluzík M, Mráz M, Svačina Š. Balancing benefits and risks in patients receiving incretin-based therapies: focus on cardiovascular and pancreatic side effects. Drug Saf 2015; 37:1003-10. [PMID: 25391858 DOI: 10.1007/s40264-014-0238-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Incretin-based therapies either increase endogenous levels of glucagon-like peptide-1 by prolonging its half-life (DPP-4 inhibitors) or directly stimulate its receptor (glucagon-like peptide-1 analogues; GLP-1 RA). They are currently widely used for the treatment of patients with type 2 diabetes mellitus owing to good antidiabetic efficacy, low risk of hypoglycemia, and relatively few other side effects. They also offer potential additional benefits such as weight neutrality or weight loss, positive effects on blood pressure and lipid levels, and potential cardio- and neuroprotectivity. Some experimental and clinical studies have raised concerns with respect to potential cardiovascular and pancreatic side effects of these therapies such as increased risk of heart failure with DPP-4 inhibitors as well as acute pancreatitis and pancreatic cancer with both classes. The available data are at present not robust enough to enable firm conclusions regarding these potential associations. Nevertheless, some recent data suggest a possibility of slightly increased risk of acute pancreatitis with GLP-1 RAs while they do not indicate increased risk of pancreatic cancer. Ongoing cardiovascular outcome trials will shed more light on the possible cardioprotective effects of incretin-based therapies as well as on the possible interconnection of DPP-4 inhibitors and heart failure.
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Affiliation(s)
- Martin Haluzík
- 3rd Dept. of Medicine, 1st Faculty of Medicine and General University Hospital, Charles University, U Nemocnice 1, 128 08, Prague 2, Czech Republic,
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Sandoval DA, D'Alessio DA. Physiology of proglucagon peptides: role of glucagon and GLP-1 in health and disease. Physiol Rev 2015; 95:513-48. [PMID: 25834231 DOI: 10.1152/physrev.00013.2014] [Citation(s) in RCA: 286] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The preproglucagon gene (Gcg) is expressed by specific enteroendocrine cells (L-cells) of the intestinal mucosa, pancreatic islet α-cells, and a discrete set of neurons within the nucleus of the solitary tract. Gcg encodes multiple peptides including glucagon, glucagon-like peptide-1, glucagon-like peptide-2, oxyntomodulin, and glicentin. Of these, glucagon and GLP-1 have received the most attention because of important roles in glucose metabolism, involvement in diabetes and other disorders, and application to therapeutics. The generally accepted model is that GLP-1 improves glucose homeostasis indirectly via stimulation of nutrient-induced insulin release and by reducing glucagon secretion. Yet the body of literature surrounding GLP-1 physiology reveals an incompletely understood and complex system that includes peripheral and central GLP-1 actions to regulate energy and glucose homeostasis. On the other hand, glucagon is established principally as a counterregulatory hormone, increasing in response to physiological challenges that threaten adequate blood glucose levels and driving glucose production to restore euglycemia. However, there also exists a potential role for glucagon in regulating energy expenditure that has recently been suggested in pharmacological studies. It is also becoming apparent that there is cross-talk between the proglucagon derived-peptides, e.g., GLP-1 inhibits glucagon secretion, and some additive or synergistic pharmacological interaction between GLP-1 and glucagon, e.g., dual glucagon/GLP-1 agonists cause more weight loss than single agonists. In this review, we discuss the physiological functions of both glucagon and GLP-1 by comparing and contrasting how these peptides function, variably in concert and opposition, to regulate glucose and energy homeostasis.
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Affiliation(s)
- Darleen A Sandoval
- Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - David A D'Alessio
- Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
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Rajan S, Dickson LM, Mathew E, Orr CMO, Ellenbroek JH, Philipson LH, Wicksteed B. Chronic hyperglycemia downregulates GLP-1 receptor signaling in pancreatic β-cells via protein kinase A. Mol Metab 2015; 4:265-76. [PMID: 25830090 PMCID: PMC4354925 DOI: 10.1016/j.molmet.2015.01.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 01/21/2015] [Accepted: 01/26/2015] [Indexed: 02/07/2023] Open
Abstract
Objective Glucagon-like peptide 1 (GLP-1) enhances insulin secretion and protects β-cell mass. Diabetes therapies targeting the GLP-1 receptor (GLP-1R), expressed in numerous tissues, have diminished dose-response in patients with type 2 diabetes compared with healthy human controls. The aim of this study was to determine the mechanistic causes underlying the reduced efficacy of GLP-1R ligands. Methods Using primary mouse islets and the β-cell line MIN6, outcomes downstream of the GLP-1R were analyzed: Insulin secretion; phosphorylation of the cAMP-response element binding protein (CREB); cAMP responses. Signaling systems were studied by immunoblotting and qRT-PCR, and PKA activity was assayed. Cell surface localization of the GLP-1R was studied by confocal microscopy using a fluorescein-tagged exendin-4 and GFP-tagged GLP-1R. Results Rodent β-cells chronically exposed to high glucose had diminished responses to GLP-1R agonists including: diminished insulin secretory response; reduced phosphorylation of (CREB); impaired cAMP response, attributable to chronically increased cAMP levels. GLP-1R signaling systems were affected by hyperglycemia with increased expression of mRNAs encoding the inducible cAMP early repressor (ICER) and adenylyl cyclase 8, reduced PKA activity due to increased expression of the PKA-RIα subunit, reduced GLP-1R mRNA expression and loss of GLP-1R from the cell surface. To specifically examine the loss of GLP-1R from the plasma membrane a GLP-1R-GFP fusion protein was employed to visualize subcellular localization. Under low glucose conditions or when PKA activity was inhibited, GLP-1R-GFP was found at the plasma membrane. Conversely high glucose, expression of a constitutively active PKA subunit, or exposure to exendin-4 or forskolin led to GLP-1R-GFP internalization. Mutation of serine residue 301 of the GLP-1R abolished the glucose-dependent loss of the receptor from the plasma membrane. This was associated with a loss of an interaction between the receptor and the small ubiquitin-related modifier (SUMO), an interaction that was found to be necessary for internalization of the receptor. Conclusions These data show that glucose acting, at least in part, via PKA leads to the loss of the GLP-1R from the cell surface and an impairment of GLP-1R signaling, which may underlie the reduced clinical efficacy of GLP-1R based therapies in individuals with poorly controlled hyperglycemia.
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Affiliation(s)
- Sindhu Rajan
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA
| | - Lorna M Dickson
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA
| | - Elizabeth Mathew
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA
| | - Caitlin M O Orr
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA ; Committee on Molecular Metabolism and Nutrition, The University of Chicago, USA
| | - Johanne H Ellenbroek
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA
| | - Louis H Philipson
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA ; Committee on Molecular Metabolism and Nutrition, The University of Chicago, USA
| | - Barton Wicksteed
- Kovler Diabetes Center, The University of Chicago, USA ; Department of Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, USA ; Committee on Molecular Metabolism and Nutrition, The University of Chicago, USA
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Narendran P, Solomon TP, Kennedy A, Chimen M, Andrews RC. The time has come to test the beta cell preserving effects of exercise in patients with new onset type 1 diabetes. Diabetologia 2015; 58:10-8. [PMID: 25367458 DOI: 10.1007/s00125-014-3412-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/22/2014] [Indexed: 12/14/2022]
Abstract
Type 1 diabetes is characterised by immune-mediated destruction of insulin-producing beta cells. Significant beta cell function is usually present at the time of diagnosis with type 1 diabetes, and preservation of this function has important clinical benefits. The last 30 years have seen a number of largely unsuccessful trials for beta cell preservation, some of which have been of therapies that have potential for significant harm. There is a need to explore new, more tolerable approaches to preserving beta cell function that can be implemented on a large clinical scale. Here we review the evidence for physical exercise as a therapy for the preservation of beta cell function in patients with newly diagnosed type 1 diabetes. We highlight possible mechanisms by which exercise could preserve beta cell function and then present evidence from other models of diabetes that demonstrate that exercise preserves beta cell function. We conclude by proposing that there is now a need for studies to explore whether exercise can preserve beta cell in patients newly diagnosed with type 1 diabetes.
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Affiliation(s)
- Parth Narendran
- The Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK,
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Aaboe K, Akram S, Deacon CF, Holst JJ, Madsbad S, Krarup T. Restoration of the insulinotropic effect of glucose-dependent insulinotropic polypeptide contributes to the antidiabetic effect of dipeptidyl peptidase-4 inhibitors. Diabetes Obes Metab 2015; 17:74-81. [PMID: 25243647 DOI: 10.1111/dom.12395] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 09/14/2014] [Accepted: 09/15/2014] [Indexed: 01/31/2023]
Abstract
AIMS To examine whether 12 weeks of treatment with a dipeptidyl peptidase-4 (DPP-4) inhibitor, sitagliptin, influences the insulin secretion induced by glucose, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) during a hyperglycaemic clamp in patients with type 2 diabetes (T2DM). METHODS A randomized, double-blind, placebo-controlled study was conducted over 12 weeks, during which 25 patients with T2DM completed treatment with either sitagliptin (100 mg once daily) or placebo as add-on therapy to metformin [sitagliptin group (n = 12): mean ± standard error of the mean (s.e.m.) age 54 ± 2.5 years, mean ± s.e.m. HbA1c 7.8 ± 0.2%; placebo group (n = 13): mean ± s.e.m. age: 57 ± 3.0 years, mean ± s.e.m. HbA1c 7.9 ± 0.2 %]. In weeks 1 and 12, the patients underwent three 2-h 15-mM hyperglycaemic clamp experiments with infusion of either saline, GLP-1 or GIP. β-cell function was evaluated according to first-phase, second-phase, incremental and total insulin and C-peptide responses. RESULTS In the sitagliptin group, the mean HbA1c concentration was significantly reduced by 0.9% (p = 0.01). The total β-cell response during GIP infusion improved significantly from week 1 to week 12, both within the sitagliptin group (p = 0.004) and when compared with the placebo group (p = 0.04). The total β-cell response during GLP-1 infusion was significantly higher (p = 0.001) when compared with saline and GIP infusion, but with no improvement from week 1 to week 12. No significant changes in β-cell function occurred in the placebo group. CONCLUSIONS Treatment with the DPP-4 inhibitor sitagliptin over 12 weeks in patients with T2DM partially restored the lost insulinotropic effect of GIP, whereas the preserved insulinotropic effect of GLP-1 was not further improved. A gradual enhancement of the insulinotropic effect of GIP, therefore, possibly contributes to the antidiabetic actions of DPP-4 inhibitors.
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Affiliation(s)
- K Aaboe
- Department of Endocrinology I, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
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Mikada A, Narita T, Yokoyama H, Yamashita R, Horikawa Y, Tsukiyama K, Yamada Y. Effects of miglitol, sitagliptin, and initial combination therapy with both on plasma incretin responses to a mixed meal and visceral fat in over-weight Japanese patients with type 2 diabetes. "the MASTER randomized, controlled trial". Diabetes Res Clin Pract 2014; 106:538-47. [PMID: 25451890 DOI: 10.1016/j.diabres.2014.09.040] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 08/01/2014] [Accepted: 09/14/2014] [Indexed: 10/24/2022]
Abstract
AIM To assess changes in circulating incretin levels and body fat compositions with initial combination therapy with α-glucosidase inhibitor and dipeptidyl peptidase-4 inhibitor in patients with type 2 diabetes (T2D). METHODS In this multicenter open-label 24-week trial, Japanese over-weight (BMI ≥ 25 kg/m(2)) patients with T2D not taking medication or taking metformin and/or sulfonylurea were randomly assigned to receive either 50mg of miglitol three times a day (M, n=14), 50mg of sitagliptin once a day (S, n=14), or a combination of both (M+S, n=13). Changes in plasma incretin levels during a meal tolerance test (MTT) and body fat composition with impedance method were evaluated. RESULTS During MTT, postprandial plasma glucose levels decreased more after M+S than after M or S, and postprandial serum insulin levels decreased significantly after M and M+S whereas they increased after S. After M, active gastric inhibitory polypeptide (aGIP) decreased significantly at 30 min despite a significant increase at 120 min. After S, aGIP levels increased significantly throughout the MTT. After M+S, aGIP increased significantly at 0 and 120 min despite of significant decrease at 30 min. M+S further enhanced postprandial active glucagon-like peptide-1 levels during MTT than S did. Total body fat mass decreased significantly after M and M+S. Visceral fat mass decreased significantly only after M+S. Serum adiponectin increased significantly only after M+S. CONCLUSIONS In over-weight patients with T2D, M+S may have a beneficial effect on adiposity with relation to these different effects on two incretins.
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Affiliation(s)
- Atsushi Mikada
- Akita University Graduate School of Medicine, Department of Endocrinology, Diabetes and Geriatric Medicine, Akita, Japan; Hiraka General Hospital, Gastroenterology and Diabetes Unit, Yokote, Japan
| | - Takuma Narita
- Akita University Graduate School of Medicine, Department of Endocrinology, Diabetes and Geriatric Medicine, Akita, Japan.
| | | | - Risa Yamashita
- Jiyugaoka Medical Clinic, Internal Medicine, Obihiro, Japan
| | - Yohei Horikawa
- Hiraka General Hospital, Gastroenterology and Diabetes Unit, Yokote, Japan
| | - Katsushi Tsukiyama
- Hiraka General Hospital, Gastroenterology and Diabetes Unit, Yokote, Japan; Akita University School of Medicine, Metabolism and Clinical Nutrition, Akita, Japan
| | - Yuichiro Yamada
- Akita University Graduate School of Medicine, Department of Endocrinology, Diabetes and Geriatric Medicine, Akita, Japan
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Broide E, Bloch O, Ben-Yehudah G, Cantrell D, Shirin H, Rapoport MJ. Reduced GLP-1R expression in gastric glands of patients with type 2 diabetes mellitus. J Clin Endocrinol Metab 2014; 99:E1691-5. [PMID: 24878048 DOI: 10.1210/jc.2014-1114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND The incretin effect is reduced in type 2 diabetes mellitus (T2DM) patients. Whether the impaired function of the enteropancreatic axis in these patients is due to defective GLP-1 receptor (GLP-1R) expression in extrapancreatic target organs is not known. AIMS AND METHODS To compare the GLP-1R expression and distribution in gastric mucosa biopsies of patients with (n =22) and without (n =22) T2DM referred for routine esophagogastroduodenoscopies. GLP-1R mRNA levels were estimated by real-time PCR. The intensity of GLP-1R immunostaining, frequency, and types of glandular cells bearing GLP-1R and their glandular distribution in different stomach mucosa regions were evaluated by immunohistochemical morphological semiquantitative and quantitative analysis. RESULTS Mean mRNA GLP-1R levels were significantly reduced in patients with T2DM compared with nondiabetic patients (P < .02). Immunohistochemical analysis revealed that the reduced GLP-1R expression in T2DM patients was due to a decreased intensity of immunostaining (P < .01). The number of glandular GLP-1R-bearing cells in both body and antrum mucosa was decreased in T2DM patients. Most notably, the frequency of GLP-1R immunoreactive acid-secreting parietal cells was reduced in the neck area of the gastric principal glands of T2DM patients (P < .01). No correlation was found between the reduced GLP-1R expression and clinical parameters including body mass index, age, glycosylated hemoglobin, and disease duration. CONCLUSION This is the first evidence of reduced GLP-1R expression in gastric glands of T2DM patients. These data demonstrate that the defective function of the incretin axis in T2DM may also result from decreased GLP-1R expression in its extrapancreatic target organs.
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Affiliation(s)
- E Broide
- Institute of Gastroenterology (E.B., G.B.-Y., H.S.), Diabetes and Immunology Research Laboratory (O.B, M.J.R.), and Department of Internal Medicine "C" (D.C., M.J.R), Assaf Harofeh Medical Center, Zerifin 70300, Israel; and Sackler Faculty of Medicine Tel Aviv University (E.B., O.B., G.B.-Y., D.C., H.S., M.J.R., Tel Aviv 69978, Israel
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Fujisawa K, Yasuda T, Kaneto H, Katakami N, Tsuji M, Kubo F, Sasaki S, Miyashita K, Naka T, Kasami R, Kuroda A, Matsuhisa M, Shimomura I. Short- and long-term effect of sitagliptin after near normalization of glycemic control with insulin in poorly controlled Japanese type 2 diabetic patients. J Diabetes Investig 2013; 5:548-53. [PMID: 25411623 PMCID: PMC4188113 DOI: 10.1111/jdi.12176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 08/15/2013] [Accepted: 10/11/2013] [Indexed: 01/19/2023] Open
Abstract
AIMS/INTRODUCTION The aim of the present study was to examine the short- and long-term effect of sitagliptin on glucose tolerance after near normalization of glycemic control with insulin in poorly controlled type 2 diabetic patients. MATERIALS AND METHODS We consecutively enrolled a total of 30 type 2 diabetic patients whose glycated hemoglobin levels (National Glycohemoglobin Standardization Program) were ≥7.4%, stopped all oral antidiabetic drugs and started insulin therapy. When fasting plasma glucose levels became <140 mg/dL, we carried out the first oral glucose tolerance test (OGTT). After 1-week sitagliptin treatment (50 mg/day), the second OGTT was carried out. Furthermore, we evaluated the long-term efficacy of sitagliptin on glucose tolerance after near normalization of glycemic control with insulin. RESULTS After 1-week sitagliptin treatment, the area under the curve of insulin was markedly increased, and the area under the curve of glucagon and glucose was markedly decreased. Duration of diabetes and insulin secretory capacity were correlated with the effect of sitagliptin. Furthermore, interestingly, near normalization of glycemic control with insulin therapy for 1-2 weeks brought out the long-term effectiveness of sitagliptin on glucose tolerance for 24 weeks, which was not observed with other antidiabetic drugs. CONCLUSIONS These findings suggest that near normalization of glycemic control with insulin improves the clinical response to sitagliptin in poorly controlled type 2 diabetic patients.
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Affiliation(s)
- Keiko Fujisawa
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
| | - Tetsuyuki Yasuda
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
| | - Hideaki Kaneto
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
| | - Naoto Katakami
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
| | - Mayumi Tsuji
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
| | - Fumiyo Kubo
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
| | - Shugo Sasaki
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
| | - Kazuyuki Miyashita
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
| | - Toyoko Naka
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
| | - Ryuuichi Kasami
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
| | - Akio Kuroda
- Diabetes Therapeutics and Research Center Tokushima University Tokushima Japan
| | - Munehide Matsuhisa
- Diabetes Therapeutics and Research Center Tokushima University Tokushima Japan
| | - Iichiro Shimomura
- Department of Metabolic Medicine Osaka University Graduate School of Medicine Osaka Japan
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Arakawa M, Ebato C. Efficacy of liraglutide as a follow-up therapy after resolution of glucotoxicity with intensive insulin therapy. Diabetes Metab Syndr 2013; 7:223-225. [PMID: 24290089 DOI: 10.1016/j.dsx.2013.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To assess the utility of liraglutide, a GLP-1 receptor agonist, as additional therapy following resolution of glucotoxicity with insulin therapy. METHODS The subjects were 13 Japanese patients with short-duration type 2 diabetes mellitus (2.0 ± 2.1 years). At first, treatment with insulin therapy consisted of bolus insulin before each meal and basal insulin at bed time commenced to improve every preprandial glucose levels below 130 mg/dL. Then, insulin therapy was replaced with liraglutide monotherapy in case in which 50% or more self-monitoring of blood glucose (SMBG) tests revealed preprandial glucose levels of less than 130 mg/dL at least for one month. Liraglutide dosing was initiated at 0.3 mg/day and increased in weekly or biweekly increments of 0.3 mg/day, to the maximum permissible dose (in Japan) of 0.9 mg/day. The participants were treated with liraglutide for 24 weeks. RESULTS The average insulin therapy period was 13.2 ± 5.4 weeks, and insulin therapy significantly improved HbA1c values from 12.4% ± 1.6% to 6.8% ± 0.9% (P < 0.05). After improvement of hyperglycemia with insulin therapy and switching to liraglutide monotherapy for 24 weeks, HbA1c values remained constant (6.2% ± 1.0% at week 24) and the rates of hypoglycemic episodes significantly decreased (P < 0.05). CONCLUSIONS These data suggest that liraglutide is proposed as an alternative follow-up therapy subsequent to eliminate glucotoxicity with insulin therapy.
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Affiliation(s)
- Masayuki Arakawa
- Yashio Central General Hospital, 1-41-3 Midoricho, Yashio, Saitama 340-0808, Japan.
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Herzberg-Schäfer S, Heni M, Stefan N, Häring HU, Fritsche A. Impairment of GLP1-induced insulin secretion: role of genetic background, insulin resistance and hyperglycaemia. Diabetes Obes Metab 2012; 14 Suppl 3:85-90. [PMID: 22928568 DOI: 10.1111/j.1463-1326.2012.01648.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
One major risk factor of type 2 diabetes is the impairment of glucose-induced insulin secretion which is mediated by the individual genetic background and environmental factors. In addition to impairment of glucose-induced insulin secretion, impaired glucagon-like peptide (GLP)1-induced insulin secretion has been identified to be present in subjects with diabetes and impaired glucose tolerance, but little is known about its fundamental mechanisms. The state of GLP1 resistance is probably an important mechanism explaining the reduced incretin effect observed in type 2 diabetes. In this review, we address methods that can be used for the measurement of insulin secretion in response to GLP1 in humans, and studies showing that specific diabetes risk genes are associated with resistance of the secretory function of the β-cell in response to GLP1 administration. Furthermore, we discuss other factors that are associated with impaired GLP1-induced insulin secretion, for example, insulin resistance. Finally, we provide evidence that hyperglycaemia per se, the genetic background and their interaction result in the development of GLP1 resistance of the β-cell. We speculate that the response or the non-response to therapy with GLP1 analogues and/or dipeptidyl peptidase-4 (DPP-IV) inhibitors is critically dependent on GLP1 resistance.
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Affiliation(s)
- S Herzberg-Schäfer
- Division of Endocrinology, Diabetology, Nephrology, Vascular Disease and Clinical Chemistry, Department of Internal Medicine, Eberhard Karls University, Tübingen, Germany
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Fujishima Y, Maeda N, Inoue K, Kashine S, Nishizawa H, Hirata A, Kozawa J, Yasuda T, Okita K, Imagawa A, Funahashi T, Shimomura I. Efficacy of liraglutide, a glucagon-like peptide-1 (GLP-1) analogue, on body weight, eating behavior, and glycemic control, in Japanese obese type 2 diabetes. Cardiovasc Diabetol 2012; 11:107. [PMID: 22973968 PMCID: PMC3459720 DOI: 10.1186/1475-2840-11-107] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 09/07/2012] [Indexed: 01/11/2023] Open
Abstract
Background We recently reported that short-term treatment with liraglutide (20.0 ± 6.4 days) reduced body weight and improved some scales of eating behavior in Japanese type 2 diabetes inpatients. However, it remained uncertain whether such liraglutide-induced improvement is maintained after discharge from the hospital. The aim of the present study was to determine the long-term effects of liraglutide on body weight, glycemic control, and eating behavior in Japanese obese type 2 diabetics. Methods Patients with obesity (body mass index (BMI) >25 kg/m2) and type 2 diabetes were hospitalized at Osaka University Hospital between November 2010 and December 2011. BMI and glycated hemoglobin (HbA1c) were examined on admission, at discharge and at 1, 3, and 6 months after discharge. For the liraglutide group (BMI; 31.3 ± 5.3 kg/m2, n = 29), patients were introduced to liraglutide after correction of hyperglycemic by insulin or oral glucose-lowering drugs and maintained on liraglutide after discharge. Eating behavior was assessed in patients treated with liraglutide using The Guideline For Obesity questionnaire issued by the Japan Society for the Study of Obesity, at admission, discharge, 3 and 6 months after discharge. For the insulin group (BMI; 29.1 ± 3.0 kg/m2, n = 28), each patient was treated with insulin during hospitalization and glycemic control maintained by insulin after discharge. Results Liraglutide induced significant and persistent weight loss from admission up to 6 months after discharge, while no change in body weight after discharge was noted in the insulin group. Liraglutide produced significant improvements in all major scores of eating behavior questionnaire items and such effect was maintained at 6 months after discharge. Weight loss correlated significantly with the decrease in scores for recognition of weight and constitution, sense of hunger, and eating style. Conclusion Liraglutide produced meaningful long-term weight loss and significantly improved eating behavior in obese Japanese patients with type 2 diabetes.
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Affiliation(s)
- Yuya Fujishima
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, 2-2-B5, Yamada-oka, Suita, Osaka 565-0871, Japan
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Jensen DH, Aaboe K, Henriksen JE, Vølund A, Holst JJ, Madsbad S, Krarup T. Steroid-induced insulin resistance and impaired glucose tolerance are both associated with a progressive decline of incretin effect in first-degree relatives of patients with type 2 diabetes. Diabetologia 2012; 55:1406-16. [PMID: 22286551 DOI: 10.1007/s00125-012-2459-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 12/28/2011] [Indexed: 11/27/2022]
Abstract
AIMS/HYPOTHESIS The aim of this study was to evaluate the separate impact of insulin resistance and impaired glucose tolerance (IGT) on the incretin effect. METHODS Twenty-one healthy glucose-tolerant first-degree relatives of patients with type 2 diabetes underwent a 75 g OGTT, an isoglycaemic i.v. glucose test and a mixed meal to evaluate the incretin effect before and after treatment with dexamethasone to increase insulin resistance. Beta cell glucose sensitivity, beta cell index and fasting proinsulin were measured as indices of beta cell function. RESULTS After dexamethasone, ten individuals had increased insulin resistance but normal glucose tolerance (NGT), while 11 individuals with an equal increase in insulin resistance developed IGT. In the NGT and IGT groups, the incretin effects were 71 ± 3.2% and 67 ± 4.6% (p = 0.4) before treatment, but decreased significantly in both groups to 58 ± 5.2% and 32 ± 8.8% (p < 0.05 between groups) after treatment. Dexamethasone increased total glucagon-like peptide-1 and glucose-dependent insulinotropic peptide responses to the OGTT. The impaired incretin effect in NGT was observed in the absence of reductions in beta cell glucose sensitivity and beta cell index during i.v. glucose, corrected for insulin resistance, but in parallel with increased proinsulin/C-peptide ratio. CONCLUSION/INTERPRETATION Insulin resistance and IGT, representing two stages in the path towards diabetes, are associated with differential reductions in the incretin effect seen before the development of IGT and overt type 2 diabetes. The reduction is unrelated to secretion of incretin hormones, but is related to insulin resistance and subtle beta cell defects, and is further aggravated on development of IGT. TRIAL REGISTRATION ClinicalTrials.gov NCT00784745. FUNDING This study was supported by a grant from the Novo Nordisk Foundation.
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Affiliation(s)
- D H Jensen
- Department of Endocrinology, Bispebjerg University Hospital, Bispebjerg Bakke 23, DK-2400 Copenhagen, Denmark.
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Abstract
Health care providers and patients have lots of choice to treat type 2 diabetes, but the blood glucose improvement is limited. The one therapy with unlimited potential (at least theoretically) is insulin. Many studies show that glucose control is achievable with insulin safely in most patients with type 2 diabetes. Effective diabetes management at the primary care or specialty level requires a belief in the importance of insulin therapy in uncontrolled patients with type 2 diabetes. This review details the theories, observed outcomes, and how-tos regarding insulin use in type 2 diabetes.
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Affiliation(s)
- Jack L Leahy
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Vermont, Colchester Research Facility, Room 110, 208 South Park Drive, Colchester, VT 05446, USA
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Normalization of fasting hyperglycemia is beneficial for successful introduction of small amount of the GLP-1 analog liraglutide in an obese patient with type 2 diabetes mellitus. Diabetol Int 2011. [DOI: 10.1007/s13340-011-0052-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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Abstract
AIMS To describe Phase 1 and 2 clinical trials of liraglutide with a focus on clinical pharmacology. KEY FINDINGS In early clinical trials of liraglutide, 0.05-1.9 mg daily improved multiple aspects of glycaemic control and beta-cell function. Early trials demonstrated typical reductions in glycated haemoglobin (HbA(1c) ) and fasting plasma glucose (FPG) of up to 1.5% and 3.3-3.9 mmol/l, respectively, at daily doses of 1.25-1.9 mg, with 45-50% of patients reaching HbA(1c) < 7%. The effects of liraglutide in restoring beta-cell response to fasting and postprandial hyperglycaemia and in reinstating near-normal insulin secretion under hyperglycaemic conditions suggest a beta-cell-protective effect. By delaying gastric emptying and promoting satiety, liraglutide is weight sparing at low doses and causes clinically meaningful weight loss at higher doses and in combination with other anti-diabetes therapies with weight-modifying benefits, such as metformin. Significant improvements in other cardiovascular risk factors, including blood pressure, lipids and cardiovascular risk biomarkers, were also evident. Adverse effects of liraglutide were primarily gastrointestinal; dose-dependent nausea was the most commonly reported effect, but was typically mild-to-moderate in severity and transient in nature. CONCLUSIONS Early clinical trials of liraglutide indicate the ability to improve glycaemic control in a glucose-dependent manner, with low risk of hypoglycaemia. Promotion of weight loss, along with improvements in multiple cardiovascular risk factors, suggests that liraglutide may offer a novel and clinically valuable approach to disease management for patients with type 2 diabetes.
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Affiliation(s)
- W E Schmidt
- Dept of Medicine I, St. Josef Hospital, Ruhr-University of Bochum Medical School, Bochum, Germany.
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