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Kern KA, DiBrog AM, Kaur K, Przybysz JT, Mietlicki-Baase EG. Chronic pramlintide decreases feeding via a reduction in meal size in male rats. Peptides 2024; 176:171197. [PMID: 38493922 DOI: 10.1016/j.peptides.2024.171197] [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: 01/10/2024] [Revised: 02/29/2024] [Accepted: 03/14/2024] [Indexed: 03/19/2024]
Abstract
Amylin, a pancreatic hormone, is well-established to suppress feeding by enhancing satiation. Pramlintide, an amylin analog that is FDA-approved for the treatment of diabetes, has also been shown to produce hypophagia. However, the behavioral mechanisms underlying the ability of pramlintide to suppress feeding are unresolved. We hypothesized that systemic pramlintide administration in rats would reduce energy intake, specifically by reducing meal size. Male rats were given b.i.d. administration of intraperitoneal pramlintide or vehicle for 1 week, and chow intake, meal patterns, and body weight were monitored throughout the test period. Consistent with our hypothesis, pramlintide decreased chow intake mainly via suppression of meal size, with corresponding reductions in meal duration on several days. Fewer effects on meal number or feeding rate were detected. Pramlintide also reduced weight gain over the 1-week study. These results highlight that the behavioral mechanisms by which pramlintide produces hypophagia are similar to those driven by amylin itself, and provide important insight into the ability of this pharmacotherapy to promote negative energy balance over a period of chronic administration.
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Affiliation(s)
- Katherine A Kern
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Adrianne M DiBrog
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Kiran Kaur
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Johnathan T Przybysz
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Elizabeth G Mietlicki-Baase
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA; Center for Ingestive Behavior Research, University at Buffalo, State University of New York, Buffalo, NY 14260, USA.
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2
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Bortoletto AS, Parchem RJ. A pancreatic player in dementia: pathological role for islet amyloid polypeptide accumulation in the brain. Neural Regen Res 2023; 18:2141-2146. [PMID: 37056121 PMCID: PMC10328265 DOI: 10.4103/1673-5374.369095] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/30/2022] [Accepted: 01/19/2023] [Indexed: 02/17/2023] Open
Abstract
Type 2 diabetes mellitus patients have a markedly higher risk of developing dementia. While multiple factors contribute to this predisposition, one of these involves the increased secretion of amylin, or islet amyloid polypeptide, that accompanies the pathophysiology of type 2 diabetes mellitus. Islet amyloid polypeptide accumulation has undoubtedly been implicated in various forms of dementia, including Alzheimer's disease and vascular dementia, but the exact mechanisms underlying islet amyloid polypeptide's causative role in dementia are unclear. In this review, we have summarized the literature supporting the various mechanisms by which islet amyloid polypeptide accumulation may cause neuronal damage, ultimately leading to the clinical symptoms of dementia. We discuss the evidence for islet amyloid polypeptide deposition in the brain, islet amyloid polypeptide interaction with other amyloids implicated in neurodegeneration, neuroinflammation caused by islet amyloid polypeptide deposition, vascular damage induced by islet amyloid polypeptide accumulation, and islet amyloid polypeptide-induced cytotoxicity. There are very few therapies approved for the treatment of dementia, and of these, clinical responses have been controversial at best. Therefore, investigating new, targetable pathways is vital for identifying novel therapeutic strategies for treating dementia. As such, we conclude this review by discussing islet amyloid polypeptide accumulation as a potential therapeutic target not only in treating type 2 diabetes mellitus but as a future target in treating or even preventing dementia associated with type 2 diabetes mellitus.
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Affiliation(s)
- Angelina S. Bortoletto
- Center for Cell and Gene Therapy, Stem Cell and Regenerative Medicine Center, Department of Neuroscience, Department of Molecular and Cellular Biology, Translational Biology and Molecular Medicine Program, Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Ronald J. Parchem
- Center for Cell and Gene Therapy, Stem Cell and Regenerative Medicine Center, Department of Neuroscience, Department of Molecular and Cellular Biology, Translational Biology and Molecular Medicine Program, Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
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3
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Sheehan A, Goldfine A, Bajwa M, Wolfs D, Kozuka C, Piper J, Fowler K, Patti ME. Pramlintide for post-bariatric hypoglycaemia. Diabetes Obes Metab 2022; 24:1021-1028. [PMID: 35137513 PMCID: PMC9035096 DOI: 10.1111/dom.14665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 01/27/2022] [Accepted: 02/06/2022] [Indexed: 11/27/2022]
Abstract
AIMS The aim of this study was to examine the hypothesis that pramlintide would reduce hypoglycaemia by slowing gastric emptying and reducing postprandial glucagon secretion, thus limiting postprandial glycaemic excursions and insulin secretion, and thus to determine the efficacy of pramlintide on frequency and severity of hypoglycaemia in post-bariatric hypoglycaemia (PBH). MATERIALS AND METHODS Participants with PBH following gastric bypass were recruited from outpatient clinics at the Joslin Diabetes Center, Boston, Massachusetts for an open-label study of pramlintide efficacy over 8 weeks. Twenty-three participants were assessed for eligibility, 20 participants had at least one pramlintide dose, and 14 completed the study. A mixed-meal tolerance test (MMTT) was performed at baseline and after 8 weeks of subcutaneous pramlintide with a sequential dose increase to a maximum of 120 micrograms (mean 69 ± 32 mcg) three times daily. The primary endpoint was change in glucose excursions during the MMTT. Secondary measures included MMTT insulin response, satiety and dumping score, percentage time with sensor glucose (SG) <3.9 mM, and number of days with minimum SG <3 mM, during masked continuous glucose monitoring. RESULTS There were no differences in MMTT glucose, glucagon or insulin between baseline and post treatment. We observed no significant change in satiety or dumping scores. The overall frequency of low SG values did not change, although there was substantial inter-individual variability. CONCLUSIONS In PBH, pramlintide does not modulate glycaemic or insulin responses, satiety, or dumping scores during an MMTT and does not impact glycaemic excursions or decrease low SG levels in the outpatient setting.
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Affiliation(s)
- Amanda Sheehan
- Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA
| | - Allison Goldfine
- Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Muhammed Bajwa
- Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA
| | - Danielle Wolfs
- Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA
| | - Chisayo Kozuka
- Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Jacqueline Piper
- Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA
| | - Kristen Fowler
- Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA
| | - Mary Elizabeth Patti
- Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
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Dunigan AI, Roseberry AG. Actions of feeding-related peptides on the mesolimbic dopamine system in regulation of natural and drug rewards. ADDICTION NEUROSCIENCE 2022; 2:100011. [PMID: 37220637 PMCID: PMC10201992 DOI: 10.1016/j.addicn.2022.100011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The mesolimbic dopamine system is the primary neural circuit mediating motivation, reinforcement, and reward-related behavior. The activity of this system and multiple behaviors controlled by it are affected by changes in feeding and body weight, such as fasting, food restriction, or the development of obesity. Multiple different peptides and hormones that have been implicated in the control of feeding and body weight interact with the mesolimbic dopamine system to regulate many different dopamine-dependent, reward-related behaviors. In this review, we summarize the effects of a selected set of feeding-related peptides and hormones acting within the ventral tegmental area and nucleus accumbens to alter feeding, as well as food, drug, and social reward.
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Affiliation(s)
- Anna I. Dunigan
- Department of Biology and Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
| | - Aaron G. Roseberry
- Department of Biology and Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
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5
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Kern KA, DiBrog AM, Przybysz JT, Mietlicki-Baase EG. Effects of pramlintide on energy intake and food preference in rats given a choice diet. Physiol Behav 2021; 240:113541. [PMID: 34332974 DOI: 10.1016/j.physbeh.2021.113541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 07/22/2021] [Accepted: 07/23/2021] [Indexed: 10/20/2022]
Abstract
Amylin is a peptide hormone involved in the control of energy balance, making the amylin system a potential target for pharmacotherapies to treat obesity. Pramlintide, an amylin analogue, is an FDA-approved medication for the treatment of diabetes that also has food intake- and body weight-suppressive effects. However, it is unknown whether pramlintide may preferentially reduce intake of highly palatable, energy dense food, the overconsumption of which is thought to play a role in the etiology of obesity. Here, we investigate the effects of pramlintide on food intake and body weight in rats given a choice of chow and high fat diet (HFD). Systemic pramlintide injection in rats reduced HFD intake at 3h post-injection, with no effects at other times and no significant effects on chow intake, body weight, or percent preference for HFD. In a separate experiment, the effects of central injection of pramlintide on food intake and body weight were similarly evaluated. Intracerebroventricular pramlintide significantly reduced HFD intake throughout the 24h post-injection, with some suppressive effects on chow intake, and also decreased 24h body weight change. Again, no significant changes were observed in the proportion of calories obtained from HFD. The same intracerebroventricular doses of pramlintide did not induce pica, suggesting that pramlintide-mediated reductions in feeding are not due to nausea/malaise. Our results suggest that pramlintide reduces food intake in rats largely via reductions in intake of HFD versus chow, supporting the idea that the potent effects of pramlintide on palatable food intake may have utility in the treatment of obesity.
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Affiliation(s)
- Katherine A Kern
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Adrianne M DiBrog
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Johnathan T Przybysz
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Elizabeth G Mietlicki-Baase
- Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, State University of New York, Buffalo, NY 14214, USA; Center for Ingestive Behavior Research, University at Buffalo, State University of New York, Buffalo, NY 14214, USA.
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6
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Farrugia F, Aquilina A, Vassallo J, Pace NP. Bisphenol A and Type 2 Diabetes Mellitus: A Review of Epidemiologic, Functional, and Early Life Factors. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:E716. [PMID: 33467592 PMCID: PMC7830729 DOI: 10.3390/ijerph18020716] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/10/2021] [Accepted: 01/13/2021] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is characterised by insulin resistance and eventual pancreatic β-cell dysfunction, resulting in persistent high blood glucose levels. Endocrine disrupting chemicals (EDCs) such as bisphenol A (BPA) are currently under scrutiny as they are implicated in the development of metabolic diseases, including T2DM. BPA is a pervasive EDC, being the main constituent of polycarbonate plastics. It can enter the human body by ingestion, through the skin, and cross from mother to offspring via the placenta or breast milk. BPA is a xenoestrogen that alters various aspects of beta cell metabolism via the modulation of oestrogen receptor signalling. In vivo and in vitro models reveal that varying concentrations of BPA disrupt glucose homeostasis and pancreatic β-cell function by altering gene expression and mitochondrial morphology. BPA also plays a role in the development of insulin resistance and has been linked to long-term adverse metabolic effects following foetal and perinatal exposure. Several epidemiological studies reveal a significant association between BPA and the development of insulin resistance and impaired glucose homeostasis, although conflicting findings driven by multiple confounding factors have been reported. In this review, the main findings of epidemiological and functional studies are summarised and compared, and their respective strengths and limitations are discussed. Further research is essential for understanding the exact mechanism of BPA action in various tissues and the extent of its effects on humans at environmentally relevant doses.
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Affiliation(s)
- Francesca Farrugia
- Department of Physiology and Biochemistry, University of Malta, MSD 2080 Msida, Malta; (F.F.); (A.A.); (J.V.)
| | - Alexia Aquilina
- Department of Physiology and Biochemistry, University of Malta, MSD 2080 Msida, Malta; (F.F.); (A.A.); (J.V.)
| | - Josanne Vassallo
- Department of Physiology and Biochemistry, University of Malta, MSD 2080 Msida, Malta; (F.F.); (A.A.); (J.V.)
- Centre for Molecular Medicine and Biobanking, University of Malta, MSD 2080 Msida, Malt
| | - Nikolai Paul Pace
- Department of Physiology and Biochemistry, University of Malta, MSD 2080 Msida, Malta; (F.F.); (A.A.); (J.V.)
- Centre for Molecular Medicine and Biobanking, University of Malta, MSD 2080 Msida, Malt
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Owen MC, Gnutt D, Gao M, Wärmländer SKTS, Jarvet J, Gräslund A, Winter R, Ebbinghaus S, Strodel B. Effects of in vivo conditions on amyloid aggregation. Chem Soc Rev 2019; 48:3946-3996. [PMID: 31192324 DOI: 10.1039/c8cs00034d] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
One of the grand challenges of biophysical chemistry is to understand the principles that govern protein misfolding and aggregation, which is a highly complex process that is sensitive to initial conditions, operates on a huge range of length- and timescales, and has products that range from protein dimers to macroscopic amyloid fibrils. Aberrant aggregation is associated with more than 25 diseases, which include Alzheimer's, Parkinson's, Huntington's, and type II diabetes. Amyloid aggregation has been extensively studied in the test tube, therefore under conditions that are far from physiological relevance. Hence, there is dire need to extend these investigations to in vivo conditions where amyloid formation is affected by a myriad of biochemical interactions. As a hallmark of neurodegenerative diseases, these interactions need to be understood in detail to develop novel therapeutic interventions, as millions of people globally suffer from neurodegenerative disorders and type II diabetes. The aim of this review is to document the progress in the research on amyloid formation from a physicochemical perspective with a special focus on the physiological factors influencing the aggregation of the amyloid-β peptide, the islet amyloid polypeptide, α-synuclein, and the hungingtin protein.
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Affiliation(s)
- Michael C Owen
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - David Gnutt
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, 38106 Braunschweig, Germany and Lead Discovery Wuppertal, Bayer AG, 42096 Wuppertal, Germany
| | - Mimi Gao
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 4a, 44227 Dortmund, Germany and Sanofi-Aventis Deutschland GmbH, R&D, Industriepark Höchst, 65926 Frankfurt, Germany
| | - Sebastian K T S Wärmländer
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Jüri Jarvet
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Roland Winter
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 4a, 44227 Dortmund, Germany
| | - Simon Ebbinghaus
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, 38106 Braunschweig, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, 42525 Jülich, Germany. and Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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8
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Veedfald S, Wu T, Bound M, Grivell J, Hartmann B, Rehfeld JF, Deacon CF, Horowitz M, Holst JJ, Rayner CK. Hyperosmolar Duodenal Saline Infusion Lowers Circulating Ghrelin and Stimulates Intestinal Hormone Release in Young Men. J Clin Endocrinol Metab 2018; 103:4409-4418. [PMID: 30053031 DOI: 10.1210/jc.2018-00699] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/17/2018] [Indexed: 02/07/2023]
Abstract
CONTEXT The mechanisms regulating the postprandial suppression of ghrelin secretion remain unclear, but recent observations in rats indicate that an increase in duodenal osmolarity is associated with a reduction in ghrelin levels. Several hormones have been implicated in the regulation of ghrelin. OBJECTIVE We hypothesized that intraduodenal infusion of a hyperosmolar solution would lower plasma ghrelin concentrations. DESIGN, SETTING, PARTICIPANTS, AND INTERVENTIONS Eighteen healthy young men were studied after an overnight fast on two occasions in a randomized double-blinded fashion. A nasoduodenal catheter was positioned and isoosmolar (300 mOsm/L) or hyperosmolar (1500 mOsm/L) saline was infused intraduodenally (4 mL/min, t = 0 to 45 minutes). Venous blood was sampled at t = -45, -30, -15, 0, 15, 30, 45, 60, 75, 90, 120, and 180 minutes. MAIN OUTCOME MEASURES Plasma concentrations of ghrelin, glucagonlike peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), cholecystokinin (CCK), glucagon, pancreatic polypeptide (PP), neurotensin (NT), peptide YY (PYY), motilin, and glucose. RESULTS Ghrelin concentrations were suppressed with hyperosmolar when compared with isoosmolar saline, and remained lower until t = 180 minutes. CCK, NT, GLP-1, PYY, and glucagon all increased during hyperosmolar, but not isoosmolar, saline infusion (P < 0.01 for all), whereas GIP, PP, and motilin levels were not affected by either infusion. CONCLUSIONS Plasma ghrelin concentrations are lowered, whereas CCK, GLP-1, PYY, NT, and glucagon concentrations are augmented, by hyperosmolar duodenal content in healthy individuals. These observations have implications for the evaluation of studies comparing the effects of different types and loads of nutrients and chemicals on gut hormone secretion.
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Affiliation(s)
- Simon Veedfald
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tongzhi Wu
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
| | - Michelle Bound
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
| | - Jacqueline Grivell
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
| | - Bolette Hartmann
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
| | - Carolyn F Deacon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Michael Horowitz
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
| | - Jens J Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Christopher K Rayner
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
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Lutz TA. Gut hormones such as amylin and GLP-1 in the control of eating and energy expenditure. INTERNATIONAL JOURNAL OF OBESITY SUPPLEMENTS 2016; 6:S15-S21. [PMID: 28685025 DOI: 10.1038/ijosup.2016.4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The control of meal size is the best studied aspect of the control of energy balance, and manipulation of this system constitutes a promising target to treat obesity. A major part of this control system is based on gastrointestinal hormones such as glucagon-like peptide-1 (GLP-1) or amylin, which are released in response to a meal and which limit the size of an ongoing meal. Both amylin and GLP-1 have also been shown to increase energy expenditure in experimental rodents, but mechanistically we know much less how this effect may be mediated, which brain sites may be involved, and what the physiological relevance of these findings may be. Most studies indicate that the effect of peripheral amylin is centrally mediated via the area postrema, but other brain areas, such as the ventral tegmental area, may also be involved. GLP-1's effect on eating seems to be mainly mediated by vagal afferents projecting to the caudal hindbrain. Chronic exposure to amylin, GLP-1 or their analogs decrease food intake and body weight gain. Next to the induction of satiation, amylin may also constitute an adiposity signal and in fact interact with the adiposity signal leptin. Amylin analogs are under clinical consideration for their effect to reduce food intake and body weight in humans, and similar to rodents, amylin analogs seem to be particularly active when combined with leptin analogs.
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Affiliation(s)
- T A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich, Zurich, Switzerland.,Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland
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10
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Hinshaw L, Schiavon M, Dadlani V, Mallad A, Dalla Man C, Bharucha A, Basu R, Geske JR, Carter RE, Cobelli C, Basu A, Kudva YC. Effect of Pramlintide on Postprandial Glucose Fluxes in Type 1 Diabetes. J Clin Endocrinol Metab 2016; 101:1954-62. [PMID: 26930181 PMCID: PMC4870844 DOI: 10.1210/jc.2015-3952] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CONTEXT Early postprandial hyperglycemia and delayed hypoglycemia remain major problems in current management of type 1 diabetes (T1D). OBJECTIVE Our objective was to investigate the effects of pramlintide, known to suppress glucagon and delay gastric emptying, on postprandial glucose fluxes in T1D. DESIGN This was a single-center, inpatient, randomized, crossover study. PATIENTS Twelve patients with T1D who completed the study were analyzed. INTERVENTIONS Subjects were studied on two occasions with or without pramlintide. Triple tracer mixed-meal method and oral minimal model were used to estimate postprandial glucose turnover and insulin sensitivity (SI). Integrated liver insulin sensitivity was calculated based on glucose turnover. Plasma glucagon and insulin were measured. MAIN OUTCOME MEASURE Glucose turnover and SI were the main outcome measures. RESULTS With pramlintide, 2-hour postprandial glucose, insulin, glucagon, glucose turnover, and SI indices showed: plasma glucose excursions were reduced (difference in incremental area under the curve [iAUC], 444.0 mMmin, P = .0003); plasma insulin concentrations were lower (difference in iAUC, 7642.0 pMmin; P = .0099); plasma glucagon excursions were lower (difference in iAUC, 1730.6 pg/mlmin; P = .0147); meal rate of glucose appearance was lower (difference in iAUC: 1196.2 μM/kg fat free mass [FFM]; P = .0316), endogenous glucose production was not different (difference in iAUC: -105.5 μM/kg FFM; P = .5842), rate of glucose disappearance was lower (difference in iAUC: 1494.2 μM/kg FFM; P = .0083). SI and liver insulin sensitivity were not different between study visits (P > .05). CONCLUSIONS Inhibition of glucagon and gastric emptying delaying reduced 2-hour prandial glucose excursions in T1D by delaying meal rate of glucose appearance.
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Affiliation(s)
- Ling Hinshaw
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Michele Schiavon
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Vikash Dadlani
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Ashwini Mallad
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Chiara Dalla Man
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Adil Bharucha
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Rita Basu
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Jennifer R Geske
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Rickey E Carter
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Claudio Cobelli
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Ananda Basu
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
| | - Yogish C Kudva
- Division of Endocrinology and Metabolism (L.H., V.D., A.M., R.B., A.B., Y.C.K.), Mayo Clinic, Rochester, Minnesota; Department of Information Engineering (M.S., C.D.M., C.C.), University of Padova, Padova, Italy; Division of Gastroenterology (A.B.), Mayo Clinic, Rochester, Minnesota; Department of Health Sciences Research (J.R.G., R.E.C.), Mayo Clinic, Rochester, Minnesota 55905
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11
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Amylin-mediated control of glycemia, energy balance, and cognition. Physiol Behav 2016; 162:130-40. [PMID: 26922873 DOI: 10.1016/j.physbeh.2016.02.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/20/2016] [Accepted: 02/22/2016] [Indexed: 12/26/2022]
Abstract
Amylin, a peptide hormone produced in the pancreas and in the brain, has well-established physiological roles in glycemic regulation and energy balance control. It improves postprandial blood glucose levels by suppressing gastric emptying and glucagon secretion; these beneficial effects have led to the FDA-approved use of the amylin analog pramlintide in the treatment of diabetes mellitus. Amylin also acts centrally as a satiation signal, reducing food intake and body weight. The ability of amylin to promote negative energy balance, along with its unique capacity to cooperatively facilitate or enhance the intake- and body weight-suppressive effects of other neuroendocrine signals like leptin, have made amylin a leading target for the development of novel pharmacotherapies for the treatment of obesity. In addition to these more widely studied effects, a growing body of literature suggests that amylin may play a role in processes related to cognition, including the neurodegeneration and cognitive deficits associated with Alzheimer's disease (AD). Although the function of amylin in AD is still unclear, intriguing recent reports indicate that amylin may improve cognitive ability and reduce hallmarks of neurodegeneration in the brain. The frequent comorbidity of diabetes mellitus and obesity, as well as the increased risk for and occurrence of AD associated with these metabolic diseases, suggests that amylin-based pharmaceutical strategies may provide multiple therapeutic benefits. This review will discuss the known effects of amylin on glycemic regulation, energy balance control, and cognitive/motivational processes. Particular focus will be devoted to the current and/or potential future clinical use of amylin pharmacotherapies for the treatment of diseases in each of these realms.
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12
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Hay DL, Chen S, Lutz TA, Parkes DG, Roth JD. Amylin: Pharmacology, Physiology, and Clinical Potential. Pharmacol Rev 2016; 67:564-600. [PMID: 26071095 DOI: 10.1124/pr.115.010629] [Citation(s) in RCA: 237] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amylin is a pancreatic β-cell hormone that produces effects in several different organ systems. Here, we review the literature in rodents and in humans on amylin research since its discovery as a hormone about 25 years ago. Amylin is a 37-amino-acid peptide that activates its specific receptors, which are multisubunit G protein-coupled receptors resulting from the coexpression of a core receptor protein with receptor activity-modifying proteins, resulting in multiple receptor subtypes. Amylin's major role is as a glucoregulatory hormone, and it is an important regulator of energy metabolism in health and disease. Other amylin actions have also been reported, such as on the cardiovascular system or on bone. Amylin acts principally in the circumventricular organs of the central nervous system and functionally interacts with other metabolically active hormones such as cholecystokinin, leptin, and estradiol. The amylin-based peptide, pramlintide, is used clinically to treat type 1 and type 2 diabetes. Clinical studies in obesity have shown that amylin agonists could also be useful for weight loss, especially in combination with other agents.
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Affiliation(s)
- Debbie L Hay
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Steve Chen
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Thomas A Lutz
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - David G Parkes
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Jonathan D Roth
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
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13
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Caillon L, Hoffmann ARF, Botz A, Khemtemourian L. Molecular Structure, Membrane Interactions, and Toxicity of the Islet Amyloid Polypeptide in Type 2 Diabetes Mellitus. J Diabetes Res 2016; 2016:5639875. [PMID: 26636105 PMCID: PMC4655289 DOI: 10.1155/2016/5639875] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/03/2015] [Indexed: 12/04/2022] Open
Abstract
Human islet amyloid polypeptide (hIAPP) is the major component of the amyloid deposits found in the pancreatic islets of patients with type 2 diabetes mellitus (T2DM). Mature hIAPP, a 37-aa peptide, is natively unfolded in its monomeric state but forms islet amyloid in T2DM. In common with other misfolded and aggregated proteins, amyloid formation involves aggregation of monomers of hIAPP into oligomers, fibrils, and ultimately mature amyloid deposits. hIAPP is coproduced and stored with insulin by the pancreatic islet β-cells and is released in response to the stimuli that lead to insulin secretion. Accumulating evidence suggests that hIAPP amyloid deposits that accompany T2DM are not just an insignificant phenomenon derived from the disease progression but that hIAPP aggregation induces processes that impair the functionality and the viability of β-cells. In this review, we particularly focus on hIAPP structure, hIAPP aggregation, and hIAPP-membrane interactions. We will also discuss recent findings on the mechanism of hIAPP-membrane damage and on hIAPP-induced cell death. Finally, the development of successful antiamyloidogenic agents that prevent hIAPP fibril formation will be examined.
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Affiliation(s)
- Lucie Caillon
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
- Département de Chimie, Ecole Normale Supérieure, PSL Research University, 24 Rue Lhomond, 75005 Paris, France
- CNRS, UMR 7203 Laboratoire des Biomolécules, 75005 Paris, France
| | - Anais R. F. Hoffmann
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
- Département de Chimie, Ecole Normale Supérieure, PSL Research University, 24 Rue Lhomond, 75005 Paris, France
- CNRS, UMR 7203 Laboratoire des Biomolécules, 75005 Paris, France
| | - Alexandra Botz
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
- Département de Chimie, Ecole Normale Supérieure, PSL Research University, 24 Rue Lhomond, 75005 Paris, France
- CNRS, UMR 7203 Laboratoire des Biomolécules, 75005 Paris, France
| | - Lucie Khemtemourian
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
- Département de Chimie, Ecole Normale Supérieure, PSL Research University, 24 Rue Lhomond, 75005 Paris, France
- CNRS, UMR 7203 Laboratoire des Biomolécules, 75005 Paris, France
- *Lucie Khemtemourian:
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14
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Hjuler ST, Andreassen KV, Gydesen S, Karsdal MA, Henriksen K. KBP-042 improves bodyweight and glucose homeostasis with indices of increased insulin sensitivity irrespective of route of administration. Eur J Pharmacol 2015; 762:229-38. [PMID: 26027795 DOI: 10.1016/j.ejphar.2015.05.051] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 05/07/2015] [Accepted: 05/26/2015] [Indexed: 01/24/2023]
Abstract
KBP-042 is a synthetic peptide dual amylin- and calcitonin-receptor agonist (DACRA) developed to treat type 2 diabetes by inducing a significant weight loss while improving glucose homeostasis. In this study the aim was to compare two different formulations: An oral formulation (1mg/kg) to subcutaneous formulations of KBP-042 (2.5μg/kg, 5.0μg/kg and 7.5μg/kg) with comparable pharmacokinetic profiles. Furthermore to examine if differences in mode of action between the two different routes of administration in high-fat fed Sprague-Dawley rats were present. It was established that the subcutaneous administrations of KBP-042 were able to dose-dependently cause a significant weight-loss, reduce food intake, and improve glucose homeostasis without increasing insulin secretion, effects comparable to those observed with oral administration. At the same time, s.c. KBP-042 suppressed the inappropriate glucagon response better than the oral formulation. Furthermore, KBP-042 was found to reduce incretins GLP-1 and GIP and considerably, improve gastric emptying, and to alleviate leptin resistance, as well as insulin resistance. In conclusion, the subcutaneous route of administration was found to have the same beneficial effects on blood glucose homeostasis and weight loss as well as resistance towards important insulin and leptin, albeit with a markedly lower variation in both exposure and biological responses. These data support the application of subcutaneously delivered peptide for mechanistic studies, and highlight the potential of developing s.c. KBP-042 as a therapy for T2D.
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Affiliation(s)
- Sara T Hjuler
- Nordic Bioscience, Herlev Hovedgade 207, DK-2730 Herlev, Denmark.
| | - Kim V Andreassen
- Nordic Bioscience, Herlev Hovedgade 207, DK-2730 Herlev, Denmark
| | - Sofie Gydesen
- Nordic Bioscience, Herlev Hovedgade 207, DK-2730 Herlev, Denmark
| | - Morten A Karsdal
- Nordic Bioscience, Herlev Hovedgade 207, DK-2730 Herlev, Denmark
| | - Kim Henriksen
- Nordic Bioscience, Herlev Hovedgade 207, DK-2730 Herlev, Denmark
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15
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Gao M, Winter R. The Effects of Lipid Membranes, Crowding and Osmolytes on the Aggregation, and Fibrillation Propensity of Human IAPP. J Diabetes Res 2015; 2015:849017. [PMID: 26582333 PMCID: PMC4637101 DOI: 10.1155/2015/849017] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/16/2015] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is an age-related and metabolic disease. Its development is hallmarked, among others, by the dysfunction and degeneration of β-cells of the pancreatic islets of Langerhans. The major pathological characteristic thereby is the formation of extracellular amyloid deposits consisting of the islet amyloid polypeptide (IAPP). The process of human IAPP (hIAPP) self-association, and the intermediate structures formed as well as the interaction of hIAPP with membrane systems seem to be, at least to a major extent, responsible for the cytotoxicity. Here we present a summary and comparison of the amyloidogenic propensities of hIAPP in bulk solution and in the presence of various neutral and charged lipid bilayer systems as well as biological membranes. We also discuss the cellular effects of macromolecular crowding and osmolytes on the aggregation pathway of hIAPP. Understanding the influence of different cellular factors on hIAPP aggregation will provide more insight into the onset of T2DM and help to develop novel therapeutic strategies.
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Affiliation(s)
- Mimi Gao
- Physical Chemistry I-Biophysical Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn Street 6, 44227 Dortmund, Germany
| | - Roland Winter
- Physical Chemistry I-Biophysical Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn Street 6, 44227 Dortmund, Germany
- *Roland Winter:
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16
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Hinshaw L, Schiavon M, Mallad A, Man CD, Basu R, Bharucha AE, Cobelli C, Carter RE, Basu A, Kudva YC. Effects of delayed gastric emptying on postprandial glucose kinetics, insulin sensitivity, and β-cell function. Am J Physiol Endocrinol Metab 2014; 307:E494-502. [PMID: 25074985 PMCID: PMC4166717 DOI: 10.1152/ajpendo.00199.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Controlling meal-related glucose excursions continues to be a therapeutic challenge in diabetes mellitus. Mechanistic reasons for this need to be understood better to develop appropriate therapies. To investigate delayed gastric emptying effects on postprandial glucose turnover, insulin sensitivity, and β-cell responsivity and function, as a feasibility study prior to studying patients with type 1 diabetes, we used the triple tracer technique C-peptide and oral minimal model approach in healthy subjects. A single dose of 30 μg of pramlintide administered at the start of a mixed meal was used to delay gastric emptying rates. With delayed gastric emptying rates, peak rate of meal glucose appearance was delayed, and rate of endogenous glucose production (EGP) was lower. C-peptide and oral minimal models enabled the assessments of β-cell function, insulin sensitivity, and β-cell responsivity simultaneously. Delayed gastric emptying induced by pramlintide improved total insulin sensitivity and decreased total β-cell responsivity. However, β-cell function as measured by total disposition index did not change. The improved whole body insulin sensitivity coupled with lower rate of appearance of EGP with delayed gastric emptying provides experimental proof of the importance of evaluating pramlintide in artificial endocrine pancreas approaches to reduce postprandial blood glucose variability in patients with type 1 diabetes.
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Affiliation(s)
- Ling Hinshaw
- Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, Minnesota
| | - Michele Schiavon
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Ashwini Mallad
- Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, Minnesota
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Rita Basu
- Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, Minnesota
| | - Adil E Bharucha
- Division of Gastroenterology, Mayo Medical School, Rochester, Minnesota; and
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Rickey E Carter
- Department of Health Sciences Research, Mayo Medical School, Rochester, Minnesota
| | - Ananda Basu
- Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, Minnesota
| | - Yogish C Kudva
- Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, Minnesota;
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17
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Mietlicki-Baase EG, Hayes MR. Amylin activates distributed CNS nuclei to control energy balance. Physiol Behav 2014; 136:39-46. [PMID: 24480072 DOI: 10.1016/j.physbeh.2014.01.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 01/13/2014] [Accepted: 01/16/2014] [Indexed: 01/25/2023]
Abstract
Amylin is a pancreas-derived neuropeptide that acts in the central nervous system (CNS) to reduce food intake. Much of the literature describing the anorectic effects of amylin are focused on amylin's actions in the area postrema, a hindbrain circumventricular structure. Although the area postrema is certainly an important site that mediates the intake-suppressive effects of amylin, several pieces of evidence indicate that amylin may also promote negative energy balance through action in additional CNS nuclei, including hypothalamic and mesolimbic structures. Therefore, this review highlights the distributed neural network mediating the feeding effects of amylin signaling with special attention being devoted to the recent discovery that the ventral tegmental area is physiologically relevant for amylin-mediated control of feeding. The production of amylin by alternative, extra-pancreatic sources and its potential relevance to food intake regulation is also considered. Finally, the utility of amylin and amylin-like compounds as a component of combination pharmacotherapies for the treatment of obesity is discussed.
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Affiliation(s)
- Elizabeth G Mietlicki-Baase
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Matthew R Hayes
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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18
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Mietlicki-Baase EG, Rupprecht LE, Olivos DR, Zimmer DJ, Alter MD, Pierce RC, Schmidt HD, Hayes MR. Amylin receptor signaling in the ventral tegmental area is physiologically relevant for the control of food intake. Neuropsychopharmacology 2013; 38:1685-97. [PMID: 23474592 PMCID: PMC3717548 DOI: 10.1038/npp.2013.66] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 02/12/2013] [Accepted: 03/01/2013] [Indexed: 11/09/2022]
Abstract
The ability of amylin, a pancreatic β-cell-derived neuropeptide, to promote negative energy balance has been ascribed to neural activation at the area postrema. However, despite amylin binding throughout the brain, the possible role of amylin signaling at other nuclei in the control of food intake has been largely neglected. We show that mRNA for all components of the amylin receptor complex is expressed in the ventral tegmental area (VTA), a mesolimbic structure mediating food intake and reward. Direct activation of VTA amylin receptors reduces the intake of chow and palatable sucrose solution in rats. This effect is mediated by reductions in meal size and is not due to nausea/malaise or prolonged suppression of locomotor activity. VTA amylin receptor activation also reduces sucrose self-administration on a progressive ratio schedule. Finally, antagonist studies provide novel evidence that VTA amylin receptor blockade increases food intake and attenuates the intake-suppressive effects of a peripherally administered amylin analog, suggesting that amylin receptor signaling in the VTA is physiologically relevant for food intake control and potentially clinically relevant for the treatment of obesity.
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Affiliation(s)
- Elizabeth G Mietlicki-Baase
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine at University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Laura E Rupprecht
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Diana R Olivos
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Derek J Zimmer
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Mark D Alter
- Center for Neurobiology and Behavior, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - R Christopher Pierce
- Center for Neurobiology and Behavior, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Heath D Schmidt
- Center for Neurobiology and Behavior, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew R Hayes
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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19
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Alterations in gut hormones after laparoscopic sleeve gastrectomy: a prospective clinical and laboratory investigational study. Ann Surg 2013; 257:647-54. [PMID: 23108120 DOI: 10.1097/sla.0b013e31826e1846] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To evaluate the effect of laparoscopic sleeve gastrectomy (LSG) on fasting and meal-stimulated release of the gut hormones ghrelin, pancreatic polypeptide (PP), peptide-YY (PYY), glucagon-like peptide-1 (GLP-1), and amylin and of the adipocytokine leptin. BACKGROUND Mounting evidence suggests that the mechanisms of weight loss and the improvement in glucose metabolism seen after LSG are related not only to gastric restriction but also to neurohormonal changes. METHODS : Fasting and postprandial levels at 60 and 120 minutes after a standard test meal of the above peptides and glucose metabolism indices were evaluated in 15 consecutive morbidly obese (MO) subjects before and 6 and 12 months after LSG. As study controls, 15 lean subjects matched for age and sex were also assessed. RESULTS Body mass index values notably decreased at 6 and 12 months (P < 0.01), postoperatively. In addition, an overall improvement of the glycemic profile of MO patients was noted. After LSG, markedly decreased fasting and postprandial levels of ghrelin, amylin, and leptin were observed. A significant postprandial increase of PYY and GLP-1 levels was also noted postoperatively. Interestingly, significantly increased levels of PP were noted only at 60 minutes postprandially after LSG. CONCLUSIONS LSG markedly improved glucose homeostasis and generated significant changes in ghrelin, PP, PYY, GLP-1, amylin, and leptin levels. These multiple hormonal actions may have several beneficial effects on the underlying mechanism of weight loss, demonstrating that LSG could be more than just a restrictive bariatric operation.
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20
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Sun Y, Chen JD. Rimonabant, gastrointestinal motility and obesity. Curr Neuropharmacol 2013; 10:212-8. [PMID: 23449551 PMCID: PMC3468875 DOI: 10.2174/157015912803217297] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 06/04/2012] [Accepted: 07/09/2012] [Indexed: 01/09/2023] Open
Abstract
Background: Obesity and overweight affect more than half of the US population and are associated with a number of diseases. Rimonabant, a cannabinoid receptor 1 blocker in the endocannabinoid (EC) system, was indicated in Europe for the treatment of obesity and overweight patients with associated risk factors but withdrawn on Jan, 2009 because of side effects. Many studies have reported the effects of rimonabant on gastrointestinal (GI) motility and food intake. The aims of this review are: to review the relationship of EC system with GI motility and food intake; to review the
studies of rimonabant on GI motility, food intake and obesity; and to report the tolerance and side effects of rimonabant.
Methods: the literature (Pubmed database) was searched using keywords: rimonabant, obesity and GI motility. Results: GI motility is related with appetite, food intake and nutrients absorption. The EC system inhibits GI motility, reduces emesis and increases food intake; Rimonabant accelerates gastric emptying and intestinal transition but decreases energy metabolism and food intake. There is rapid onset of tolerance to the prokinetic effect of rimonabant. The main side effects of rimonabant are depression and GI symptoms. Conclusions: Rimonabant has significant effects on energy metabolism and food intake, probably mediated via its effects on GI motility.
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Affiliation(s)
- Yan Sun
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma City, OK
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21
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Lutz TA. The interaction of amylin with other hormones in the control of eating. Diabetes Obes Metab 2013; 15:99-111. [PMID: 22862822 DOI: 10.1111/j.1463-1326.2012.01670.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Revised: 07/20/2012] [Accepted: 07/28/2012] [Indexed: 11/30/2022]
Abstract
Twenty years of research established amylin as an important control of energy homeostasis. Amylin controls nutrient and energy fluxes by reducing energy intake, by modulating nutrient utilization via an inhibition of postprandial glucagon secretion and by increasing energy disposal via a prevention of compensatory decreases of energy expenditure in weight reduced individuals. Like many other gastrointestinal hormones, amylin is secreted in response to meals and it reduces eating by promoting meal-ending satiation. Not surprisingly, amylin interacts with many of these hormones to control eating. These interactions seem to occur at different levels because amylin seems to mediate the eating inhibitory effect of some of these gastrointestinal hormones, and the combination of some of these hormones seems to lead to a stronger reduction in eating than single hormones alone. Amylin's effect on eating is thought to be mediated by a stimulation of specific amylin receptors in the area postrema. Secondary brain sites that were defined to mediate amylin action - and hence potential additional sites of interaction with other hormones - include the nucleus of the solitary tract, the lateral parabrachial nucleus, the lateral hypothalamic area and other hypothalamic nuclei. The focus of this review is to summarize the current knowledge of amylin interactions in the control of eating. In most cases, these interactions have only been studied at a descriptive rather than a mechanistic level and despite the clear knowledge on primary sites of amylin action, the interaction sites between amylin and other hormones are often unknown.
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Affiliation(s)
- T A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
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The defence of body weight: a physiological basis for weight regain after weight loss. Clin Sci (Lond) 2013; 124:231-41. [PMID: 23126426 DOI: 10.1042/cs20120223] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Although weight loss can usually be achieved by restricting food intake, the majority of dieters regain weight over the long-term. In the hypothalamus, hormonal signals from the gastrointestinal tract, adipose tissue and other peripheral sites are integrated to influence appetite and energy expenditure. Diet-induced weight loss is accompanied by several physiological changes which encourage weight regain, including alterations in energy expenditure, substrate metabolism and hormone pathways involved in appetite regulation, many of which persist beyond the initial weight loss period. Safe effective long-term strategies to overcome these physiological changes are needed to help facilitate maintenance of weight loss. The present review, which focuses on data from human studies, begins with an outline of body weight regulation to provide the context for the subsequent discussion of short- and long-term physiological changes which accompany diet-induced weight loss.
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Panickar KS. Effects of dietary polyphenols on neuroregulatory factors and pathways that mediate food intake and energy regulation in obesity. Mol Nutr Food Res 2012; 57:34-47. [DOI: 10.1002/mnfr.201200431] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 08/08/2012] [Accepted: 08/22/2012] [Indexed: 12/20/2022]
Affiliation(s)
- Kiran S. Panickar
- Department of Pediatrics; University of Maryland School of Medicine; Baltimore MD USA
- Diet, Genomics, & Immunology Laboratory; Beltsville Human Nutrition Research Center; Agricultural Research Service; United States Department of Agriculture; Beltsville MD USA
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Abstract
Amylin is a naturally occurring hormone that regulates food intake and postprandial glucose excursions. Amylin is synthesized in the β cell and cosecreted with insulin. Type 1 diabetes and insulin-requiring Type 2 diabetes are amylin-deficient as well as insulin-deficient states. Pramlintide is a synthetic amylin analog that is used for replacement therapy. Pramlintide therapy slows diabetes-mediated accelerated gastric emptying and restores meal-mediated suppression of glucagon secretion in patients with diabetes. Amylin receptors are primarily located in the CNS, which mediates all of its effects including decreases in food intake. In patients with diabetes, pramlintide treatment reduces hemoglobin A1C (HbA1c) 0.3-0.7% and decreases bodyweight. Side effects include nausea and hypoglycemia. Both can be minimized by an appropriate titration program. Recent pramlintide studies address improvements in delivery systems, use in pediatric and Type 2 diabetic populations, patient treatment satisfaction and new insights into its mechanisms of action.
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Affiliation(s)
- Harold E Lebovitz
- a Department of Medicine, Division of Endocrinology, State University of New York Health Science Center at Brooklyn, NY, USA.
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Harrold JA, Dovey TM, Blundell JE, Halford JC. CNS regulation of appetite. Neuropharmacology 2012; 63:3-17. [DOI: 10.1016/j.neuropharm.2012.01.007] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 01/05/2012] [Accepted: 01/10/2012] [Indexed: 12/14/2022]
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Abstract
Abstract
During the period between 2000 and 2030, the number of persons older than 65 years is projected to grow from 550 to 937 million worldwide. Globally, this growth represents an increase from 6.9 to 12 %. Studies have found that 74.6 % of women and 67.4 % of men aged 65 years or older suffer from many clinical and subclinical syndromes and problems, including anorexia, undernutrition, weight loss, sarcopenia, and cachexia, which are often overlooked or managed inadequately. These issues are very common in the elder. The key clinical question is whether these changes in the elder are distinct entities or an interdependent continuum. In this article, we reviewed these issues of related basic, clinical knowledge. The purpose of this review is to enhance the recognition of anorexia, undernutrition, weight loss, sarcopenia, and cachexia.
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Lutz TA. Control of energy homeostasis by amylin. Cell Mol Life Sci 2012; 69:1947-65. [PMID: 22193913 PMCID: PMC11114503 DOI: 10.1007/s00018-011-0905-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 11/13/2011] [Accepted: 12/06/2011] [Indexed: 02/04/2023]
Abstract
Amylin is an important control of nutrient fluxes because it reduces energy intake, modulates nutrient utilization by inhibiting postprandial glucagon secretion, and increases energy disposal by preventing compensatory decreases of energy expenditure in weight-reduced individuals. The best investigated function of amylin which is cosecreted with insulin is to reduce eating by promoting meal-ending satiation. This effect is thought to be mediated by a stimulation of specific amylin receptors in the area postrema. Secondary brain sites to mediate amylin action include the nucleus of the solitary tract and the lateral parabrachial nucleus, which convey the neural signal to the lateral hypothalamic area and other hypothalamic nuclei. Amylin may also signal adiposity because plasma levels of amylin are increased in adiposity and because higher amylin concentrations in the brain result in reduced body weight gain and adiposity, while amylin receptor antagonists increase body adiposity. The central mechanisms involved in amylin's effect on energy expenditure are much less known. A series of recent experiments in animals and humans indicate that amylin is a promising option for anti-obesity therapy especially in combination with other hormones. The most extensive dataset is available for the combination therapy of amylin and leptin. Ongoing research focuses on the mechanisms of these interactions.
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Affiliation(s)
- Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich, Switzerland.
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Guyenet SJ, Schwartz MW. Clinical review: Regulation of food intake, energy balance, and body fat mass: implications for the pathogenesis and treatment of obesity. J Clin Endocrinol Metab 2012; 97:745-55. [PMID: 22238401 PMCID: PMC3319208 DOI: 10.1210/jc.2011-2525] [Citation(s) in RCA: 185] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 12/08/2011] [Indexed: 12/22/2022]
Abstract
CONTEXT Obesity has emerged as one of the leading medical challenges of the 21st century. The resistance of this disorder to effective, long-term treatment can be traced to the fact that body fat stores are subject to homeostatic regulation in obese individuals, just as in lean individuals. Because the growing obesity epidemic is linked to a substantial increase in daily energy intake, a key priority is to delineate how mechanisms governing food intake and body fat content are altered in an obesogenic environment. EVIDENCE ACQUISITION We considered all relevant published research and cited references that represented the highest quality evidence available. Where space permitted, primary references were cited. EVIDENCE SYNTHESIS The increase of energy intake that has fueled the U.S. obesity epidemic is linked to greater availability of highly rewarding/palatable and energy-dense food. Obesity occurs in genetically susceptible individuals and involves the biological defense of an elevated body fat mass, which may result in part from interactions between brain reward and homeostatic circuits. Inflammatory signaling, accumulation of lipid metabolites, or other mechanisms that impair hypothalamic neurons may also contribute to the development of obesity and offer a plausible mechanism to explain the biological defense of elevated body fat mass. CONCLUSIONS Despite steady research progress, mechanisms underlying the resistance to fat loss once obesity is established remain incompletely understood. Breakthroughs in this area may be required for the development of effective new obesity prevention and treatment strategies.
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Affiliation(s)
- Stephan J Guyenet
- Diabetes and Obesity Center of Excellence, Department of Medicine, University of Washington School of Medicine, South Lake Union, 815 Mercer Street, N334, Box 358055, Seattle, Washington 98109, USA
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Olsson M, Herrington MK, Reidelberger RD, Permert J, Gebre-Medhin S, Arnelo U. Food intake and meal pattern in IAPP knockout mice with and without infusion of exogenous IAPP. Scand J Gastroenterol 2012; 47:191-6. [PMID: 22229533 DOI: 10.3109/00365521.2011.638392] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE The current study used islet amyloid polypeptide (IAPP) knockout mice (KO mice) to investigate the physiological role of IAPP in the regulation of food intake (FI). MATERIAL AND METHODS FI and body weight were measured in KO and wild-type (WT) mice for 27 weeks. In an additional short-term experiment, IAPP (25 pmol·kg(-1)min(-1)) was infused subcutaneously for 3 days in KO and WT mice, and FI, meal pattern, and body weight were analyzed. RESULTS In the long-term experiment, no significant differences in body weight were seen between WT and KO mice at any point. FI, meal number, and meal size did not differ significantly between the groups in any of the five selected weeks that were studied. In the short-term experiment, FI decreased significantly during IAPP infusion in both WT and KO groups. FI was significantly lower in the KO mice compared with WT on days 1 and 2 (p < 0.05 and p < 0.01, respectively). CONCLUSIONS The data showing no differences in FI and body weight were seen between KO and WT mice, indicating that FI can be controlled in the absence of IAPP. The more marked anorectic effect seen in the KO mice during IAPP infusion suggests that IAPP receptors and/or IAPP post-receptor signaling pathways are up-regulated in mice lacking endogenous IAPP.
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Affiliation(s)
- Madelene Olsson
- Department for Clinical Science, Intervention and Technology (CLINTEC), Division of Surgery, Karolinska Institutet at Karolinska University Hospital, Huddinge, Stockholm, Sweden
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Kushner RF. Pharmacologic management of obesity. Pediatr Blood Cancer 2012; 58:140-3. [PMID: 22009632 DOI: 10.1002/pbc.23366] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 09/06/2011] [Indexed: 11/06/2022]
Abstract
Recent discoveries of processes that govern regulation of body weight and energy expenditure have led to development of new anti-obesity pharmacological agents. This article will inform health professionals of new anti-obesity medications that target neuronal systems within the central nervous system (CNS) and peripheral humoral proteins that send signals to the CNS. An emerging theme of new therapies is to use combination medications that are directed toward several targets or leverage existing gastrointestinal satiety hormonal signals. By using combination therapies, it is anticipated that greater weight loss will be achieved compared to monotherapy.
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Affiliation(s)
- Robert F Kushner
- Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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Horner KM, Byrne NM, Cleghorn GJ, Näslund E, King NA. The effects of weight loss strategies on gastric emptying and appetite control. Obes Rev 2011; 12:935-51. [PMID: 21729233 DOI: 10.1111/j.1467-789x.2011.00901.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The gastrointestinal tract plays an important role in the improved appetite control and weight loss in response to bariatric surgery. Other strategies which similarly alter gastrointestinal responses to food intake could contribute to successful weight management. The aim of this review is to discuss the effects of surgical, pharmacological and behavioural weight loss interventions on gastrointestinal targets of appetite control, including gastric emptying. Gastrointestinal peptides are also discussed because of their integrative relationship in appetite control. This review shows that different strategies exert diverse effects and there is no consensus on the optimal strategy for manipulating gastric emptying to improve appetite control. Emerging evidence from surgical procedures (e.g. sleeve gastrectomy and Roux-en-Y gastric bypass) suggests a faster emptying rate and earlier delivery of nutrients to the distal small intestine may improve appetite control. Energy restriction slows gastric emptying, while the effect of exercise-induced weight loss on gastric emptying remains to be established. The limited evidence suggests that chronic exercise is associated with faster gastric emptying, which we hypothesize will impact on appetite control and energy balance. Understanding how behavioural weight loss interventions (e.g. diet and exercise) alter gastrointestinal targets of appetite control may be important to improve their success in weight management.
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Affiliation(s)
- K M Horner
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
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Abstract
Gut microbiota is an assortment of microorganisms inhabiting the length and width of the mammalian gastrointestinal tract. The composition of this microbial community is host specific, evolving throughout an individual's lifetime and susceptible to both exogenous and endogenous modifications. Recent renewed interest in the structure and function of this "organ" has illuminated its central position in health and disease. The microbiota is intimately involved in numerous aspects of normal host physiology, from nutritional status to behavior and stress response. Additionally, they can be a central or a contributing cause of many diseases, affecting both near and far organ systems. The overall balance in the composition of the gut microbial community, as well as the presence or absence of key species capable of effecting specific responses, is important in ensuring homeostasis or lack thereof at the intestinal mucosa and beyond. The mechanisms through which microbiota exerts its beneficial or detrimental influences remain largely undefined, but include elaboration of signaling molecules and recognition of bacterial epitopes by both intestinal epithelial and mucosal immune cells. The advances in modeling and analysis of gut microbiota will further our knowledge of their role in health and disease, allowing customization of existing and future therapeutic and prophylactic modalities.
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Affiliation(s)
- Inna Sekirov
- Michael Smith Laboratories, Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
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Bose M, Machineni S, Oliván B, Teixeira J, McGinty JJ, Bawa B, Koshy N, Colarusso A, Laferrère B. Superior appetite hormone profile after equivalent weight loss by gastric bypass compared to gastric banding. Obesity (Silver Spring) 2010; 18:1085-91. [PMID: 20057364 PMCID: PMC2877144 DOI: 10.1038/oby.2009.473] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The goal of this study was to understand the mechanisms of greater weight loss by gastric bypass (GBP) compared to gastric banding (GB) surgery. Obese weight- and age-matched subjects were studied before (T0), after a 12 kg weight loss (T1) by GBP (n = 11) or GB (n = 9), and at 1 year after surgery (T2). peptide YY(3-36) (PYY(3-36)), ghrelin, glucagon-like peptide-1 (GLP-1), leptin, and amylin were measured after an oral glucose challenge. At T1, glucose-stimulated GLP-1 and PYY levels increased significantly after GBP but not GB. Ghrelin levels did not change significantly after either surgery. In spite of equivalent weight loss, leptin and amylin decreased after GBP, but not after GB. At T2, weight loss was greater after GBP than GB (P = 0.003). GLP-1, PYY, and amylin levels did not significantly change from T1 to T2; leptin levels continued to decrease after GBP, but not after GB at T2. Surprisingly, ghrelin area under the curve (AUC) increased 1 year after GBP (P = 0.03). These data show that, at equivalent weight loss, favorable GLP-1 and PYY changes occur after GBP, but not GB, and could explain the difference in weight loss at 1 year. Mechanisms other than weight loss may explain changes of leptin and amylin after GBP.
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Affiliation(s)
- Mousumi Bose
- New York Obesity Research Center, St Luke's Roosevelt Hospital Center, New York, New York, USA.
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Abstract
Insulin replacement therapy in type 1 diabetes mellitus (T1DM) is nonphysiologic. Hyperinsulinemia is generated in the periphery to achieve normal insulin concentrations in the liver. This mismatch results in increased hypoglycemia, increased food intake with weight gain, and insufficient regulation of postprandial glucose excursions. Islet amyloid polypeptide is a hormone synthesized in pancreatic beta cells and cosecreted with insulin. Circulating islet amyloid polypeptide binds to receptors located in the hindbrain and increases satiety, delays gastric emptying and suppresses glucagon secretion. Thus, islet amyloid polypeptide complements the effects of insulin. T1DM is a state of both islet amyloid polypeptide and insulin deficiency. Pramlintide, a synthetic analog of islet amyloid polypeptide, can replace this hormone in patients with T1DM. When administered as adjunctive therapy to such patients treated with insulin, pramlintide decreases food intake and causes weight loss. Pramlintide therapy is also associated with suppression of glucagon secretion and delayed gastric emptying, both of which decrease postprandial plasma glucose excursions. Pramlintide therapy improves glycemic control and lessens weight gain. Agents that decrease intestinal carbohydrate digestion (alpha-glucosidase inhibitors) or decrease insulin resistance (metformin) might be alternative adjunctive therapies in T1DM, though its benefits are marginally supported by clinical data.
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Affiliation(s)
- Harold E Lebovitz
- Department of Medicine, Division of Endocrinology, State University of New York Health Science Center at Brooklyn, 450 Clarkson Avenue, New York, NY 11203, USA.
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Halford JCG, Boyland EJ, Blundell JE, Kirkham TC, Harrold JA. Pharmacological management of appetite expression in obesity. Nat Rev Endocrinol 2010; 6:255-69. [PMID: 20234354 DOI: 10.1038/nrendo.2010.19] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
For obese individuals, successful weight loss and maintenance are notoriously difficult. Traditional drug development fails to exploit knowledge of the psychological factors that crucially influence appetite, concentrating instead on restrictive criteria of intake and weight reduction, allied to a mechanistic view of energy regulation. Drugs are under development that may produce beneficial changes in appetite expression in the obese. These currently include glucagon-like peptide-1 analogs such as liraglutide, an amylin analog davalintide, the 5-HT(2C) receptor agonist lorcaserin, the monoamine re-uptake inhibitor tesofensine, and a number of combination therapies such as pramlintide and metreleptin, bupropion and naltrexone, phentermine and topiramate, and bupropion and zonisamide. However, the effects of these treatments on eating behavior remain poorly characterized. Obesity is typically a consequence of overconsumption driven by an individual's natural sensitivity to food stimuli and the pleasure derived from eating. Intuitively, these processes should be effective targets for pharmacotherapy, and behavioral analysis can identify drugs that selectively affect desire to eat, enjoyment of eating, satiation or postmeal satiety. Rational interventions designed specifically to modulate these processes could limit the normally aversive consequences of caloric restriction and maximize an individual's capacity to successfully gain control over their appetite.
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Affiliation(s)
- Jason C G Halford
- School of Psychology, University of Liverpool, Eleanor Rathbone Building, Bedford Street South, Liverpool L69 7ZA, UK.
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Visvanathan R, Chapman IM. Undernutrition and anorexia in the older person. Gastroenterol Clin North Am 2009; 38:393-409. [PMID: 19699404 DOI: 10.1016/j.gtc.2009.06.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Minimizing frailty in older age is important to individuals and society, as the increasing prevalence of chronic disease is leading to greater disability and health care costs. Nutritional frailty can be defined as the disability that occurs in old age due to rapid, unintentional loss of body weight and sarcopenia (lack of lean mass). This article provides a brief overview of the prevalence and consequences of undernutrition, age-related changes to appetite, food intake, and body composition, the factors contributing to the development of anorexia and undernutrition, and recommended management strategies.
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Affiliation(s)
- Renuka Visvanathan
- Department of Medicine, University of Adelaide, Level 6 Eleanor Harrold Building, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia
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Abstract
Insulin administration is the primary therapy for type 1 diabetes mellitus (T1DM). Current available insulin therapies do not successfully enable children with T1DM to reach glycemic goals without side effects such as hypoglycemia and weight gain. Pramlintide is a synthetic analog of human amylin that acts in conjunction with insulin to delay gastric emptying and inhibit the release of glucagon and is indicated for use in patients with type 1 and type 2 diabetes. Recent studies in adult patients have examined the role of glucagon-like peptide 1 (GLP-1) and agents that bind to its receptor in type 1 diabetes. It is hypothesized that a major component of the glycemic effect is attributable to the known action of GLP-1 to delay gastric emptying and to inhibit glucagon secretion. Further studies with the use of amylin analogs and long-acting GLP-1 agonists as congeners with insulin in T1DM are indicated in children. In recent years, our better understanding of the pathophysiology of diabetes has led to the development of new therapies for diabetes. This article reviews the potential use of these newer pharmacologic agents as adjunctive therapy in T1DM in children and adolescents.
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Affiliation(s)
- Vandana S Raman
- Department of Pediatrics, Division of Pediatric Endocrinology, Baylor College of Medicine, Houston, TX 77030, USA
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Chakrabarti R. Pharmacotherapy of obesity: emerging drugs and targets. Expert Opin Ther Targets 2009; 13:195-207. [DOI: 10.1517/14728220802637063] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Trevaskis JL, Coffey T, Cole R, Lei C, Wittmer C, Walsh B, Weyer C, Koda J, Baron AD, Parkes DG, Roth JD. Amylin-mediated restoration of leptin responsiveness in diet-induced obesity: magnitude and mechanisms. Endocrinology 2008; 149:5679-87. [PMID: 18669592 DOI: 10.1210/en.2008-0770] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previously, we reported that combination treatment with rat amylin (100 microg/kg.d) and murine leptin (500 microg/kg.d) elicited greater inhibition of food intake and greater body weight loss in diet-induced obese rats than predicted by the sum of the monotherapy conditions, a finding consistent with amylin-induced restoration of leptin responsiveness. In the present study, a 3 x 4 factorial design was used to formally test for a synergistic interaction, using lower dose ranges of amylin (0, 10, and 50 microg/kg.d) and leptin (0, 5, 25, and 125 microg/kg.d), on food intake and body weight after 4 wk continuous infusion. Response surface methodology analysis revealed significant synergistic anorexigenic (P < 0.05) and body weight-lowering (P < 0.05) effects of amylin/leptin combination treatment, with up to 15% weight loss at doses considerably lower than previously reported. Pair-feeding (PF) experiments demonstrated that reduction of food intake was the predominant mechanism for amylin/leptin-mediated weight loss. However, fat loss was 2-fold greater in amylin/leptin-treated rats than PF controls. Furthermore, amylin/leptin-mediated weight loss was not accompanied by the counterregulatory decrease in energy expenditure and chronic shift toward carbohydrate (rather than fat) utilization observed with PF. Hepatic gene expression analyses revealed that 28 d treatment with amylin/leptin (but not PF) was associated with reduced expression of genes involved in hepatic lipogenesis (Scd1 and Fasn mRNA) and increased expression of genes involved in lipid utilization (Pck1 mRNA). We conclude that amylin/leptin interact synergistically to reduce body weight and adiposity in diet-induced obese rodents through a number of anorexigenic and metabolic effects.
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Abstract
BACKGROUND Recent discoveries about the metabolic and genetic control systems that govern regulation of body weight and energy expenditure have afforded the opportunity to develop pharmacological agents that can be used as adjunctive treatments for patients with obesity. However, the scarcity of medications available or those that have made it to Phase III trials reflects the difficult challenge of manipulating the biology of appetite regulation. OBJECTIVE The aim of this study was to inform health professionals about new anti-obesity medications that target neuronal systems within the central nervous system and peripheral humoral proteins that send signals to the central nervous system. METHODS A critical review was conducted of information available from the medical literature. RESULTS/CONCLUSIONS An emerging theme is to use combination therapies that are directed towards several targets or leverage existing gastrointestinal satiety hormonal signals. By using combination therapies, it is anticipated that greater weight loss will be achieved compared to monotherapy.
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Affiliation(s)
- Robert F Kushner
- Northwestern University Feinberg School of Medicine, 750 North Lake Shore Drive, Rubloff 9-976, Chicago, IL 60611, USA.
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41
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Eller LK, Ainslie PN, Poulin MJ, Reimer RA. Differential responses of circulating amylin to high-fat vs. high-carbohydrate meal in healthy men. Clin Endocrinol (Oxf) 2008; 68:890-7. [PMID: 18031323 DOI: 10.1111/j.1365-2265.2007.03129.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE The success of an amylin analogue in weight loss trials has generated interest in amylin as a physiological satiety signal. Little is known about how plasma amylin responds to macronutrients. This study examined the effects of a high-carbohydrate meal (CHO), a high-fat meal (FAT) or a continued fast (FAST) on amylin concentrations and correlations among other satiety hormones and measures of appetite. DESIGN/PATIENTS In a randomized, crossover design, 10 healthy males consumed a meal high in carbohydrate or fat or continued fasted. MEASUREMENTS Blood samples and subjective hunger scores were obtained at baseline and 30, 90 and 210 min postprandial. RESULTS After CHO, amylin, insulin and C-peptide were greater and des-acyl ghrelin lower compared to FAT (P < 0.001). Area under the curve (AUC) was greater for amylin and insulin and lower for des-acyl ghrelin following CHO. Subjective satiety and fullness were higher for CHO and FAT than FAST at 30 and 90 min but only for CHO at 210 min (P < 0.01). Hunger and desire to eat were lower for CHO and FAT than FAST at 30 and 90 min but only for CHO at 210 min (P < 0.005). Amylin was negatively correlated to hunger, desire to eat, and nausea and positively related to satiety and insulin. Des-acyl ghrelin was negatively associated with C-peptide, insulin and GLP-1 and satiety. CONCLUSIONS CHO enhances amylin and suppresses des-acyl ghrelin to a greater extent than FAT in healthy men. The mechanisms responsible for these changes and their implications in the physiology of satiety remain to be elucidated.
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Affiliation(s)
- Lindsay K Eller
- Department of Physiology and Biophysics, and Faculty of Medicine and Kinesiology, University of Calgary, Calgary, AB, Canada
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Bello NT, Kemm MH, Moran TH. Salmon calcitonin reduces food intake through changes in meal sizes in male rhesus monkeys. Am J Physiol Regul Integr Comp Physiol 2008; 295:R76-81. [PMID: 18480241 DOI: 10.1152/ajpregu.90327.2008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Amylinergic mechanisms are believed to be involved in the control of appetite. This study examined the effects of the amylin agonist, salmon calcitonin, on food intake and meal patterns in adult male rhesus monkeys. Fifteen minutes before the onset of their 6-h daily feeding period, monkeys received intramuscular injections of various doses of salmon calcitonin (0.032, 0.056, 0.1, 0.32, and 1 microg/kg) or saline. Salmon calcitonin dose dependently reduced total daily and hourly food intake, with significant decreases at the 0.1, 0.32, and 1 microg/kg doses. Daily food intake was reduced by approximately 35%, 62%, and 96%, at these doses, respectively. An analysis of meal patterns revealed that size of the first meal was significantly reduced across the dose range of 0.056 to 1 microg/kg, while average meal size was reduced with the 0.32 and 1 microg/kg doses. Meal number was only affected at the 1 microg/kg dose. Repeated 5-day administration of the 0.1 microg/kg dose resulted in a reduction in daily food intake only on injection day 2, while significant reductions in food intake were observed on all five injection days with a 0.32 microg/kg dose. Daily food intake was also reduced for 1 day after the termination of the 5-day injections of the 0.32 microg/kg salmon calcitonin dose. These sustained reductions in intake were expressed through decreases in meal size. These data demonstrate that salmon calcitonin acutely and consistently decreases food intake mainly through reductions in meal sizes in nonhuman primates.
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Affiliation(s)
- Nicholas T Bello
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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Bibliography. Current world literature. Growth and development. Curr Opin Endocrinol Diabetes Obes 2008; 15:79-101. [PMID: 18185067 DOI: 10.1097/med.0b013e3282f4f084] [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] [Indexed: 11/25/2022]
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Aronne L, Fujioka K, Aroda V, Chen K, Halseth A, Kesty NC, Burns C, Lush CW, Weyer C. Progressive reduction in body weight after treatment with the amylin analog pramlintide in obese subjects: a phase 2, randomized, placebo-controlled, dose-escalation study. J Clin Endocrinol Metab 2007; 92:2977-83. [PMID: 17504894 DOI: 10.1210/jc.2006-2003] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
CONTEXT In previous 1-yr trials, treatment with pramlintide (120 microg), an analog of the beta-cell hormone amylin, induced sustained reductions in A1C and body weight in insulin-using subjects with type 2 diabetes. OBJECTIVE To assess the potential of pramlintide as an antiobesity agent, we assessed the weight effect, safety, and tolerability of pramlintide in non-insulin-treated obese subjects with and without type 2 diabetes at doses greater than previously studied. DESIGN/SETTING We performed a randomized, double-blind, placebo-controlled, multicenter study. PATIENTS A total of 204 obese subjects [80/20% female/male, age 48 +/- 10 yr, and body mass index 37.8 +/- 5.6 kg/m(2) (mean +/- SD)] participated in the study. INTERVENTION For 16 wk, without concomitant lifestyle intervention, subjects self-administered pramlintide (nonforced dose escalation < or = 240 microg) or placebo via sc injection three times a day before meals. MAIN OUTCOME MEASURES Weight, waist circumference, tolerability, and safety were the main outcome measures. RESULTS Pramlintide was generally well tolerated, with 88% of subjects able to escalate to the maximum dose of 240 microg. Withdrawal rates were similar between placebo (25%) and pramlintide-treated subjects (29%). Subjects completing 16 wk of pramlintide treatment experienced placebo-corrected reductions in body weight of 3.7 +/- 0.5% (3.6 +/- 0.6 kg; P < 0.001) and waist circumference (3.6 +/- 1.1 cm; P < 0.01). Approximately 31% of pramlintide-treated subjects achieved > or =5% weight loss (vs. 2% placebo; P < 0.001). More pramlintide than placebo-treated subjects reported improvements in appetite control (72% vs. 31%), weight control (63% vs. 24%), and overall well-being (52% vs. 17%). No unexpected safety signals were observed. The most common adverse event reported was mild, transient nausea. Pramlintide-treated subjects not reporting nausea experienced weight loss similar to those who did (3.6 +/- 0.5% and 3.9 +/- 0.5%, respectively). CONCLUSION These results support continued evaluation of pramlintide as a potential treatment for obesity.
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Affiliation(s)
- Louis Aronne
- Weill-Cornell Medical College, New York, NY 10021, USA
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