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Korgan AC, Oliveira-Abreu K, Wei W, Martin SLA, Bridges ZJD, Leal-Cardoso JH, Kaczorowski CC, O'Connell KMS. High sucrose consumption decouples intrinsic and synaptic excitability of AgRP neurons without altering body weight. Int J Obes (Lond) 2023; 47:224-235. [PMID: 36725979 PMCID: PMC10023568 DOI: 10.1038/s41366-023-01265-w] [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: 10/04/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 02/03/2023]
Abstract
BACKGROUND/OBJECTIVE As the obesity epidemic continues, the understanding of macronutrient influence on central nervous system function is critical for understanding diet-induced obesity and potential therapeutics, particularly in light of the increased sugar content in processed foods. Previous research showed mixed effects of sucrose feeding on body weight gain but has yet to reveal insight into the impact of sucrose on hypothalamic functioning. Here, we explore the impact of liquid sucrose feeding for 12 weeks on body weight, body composition, caloric intake, and hypothalamic AgRP neuronal function and synaptic plasticity. METHODS Patch-clamp electrophysiology of hypothalamic AgRP neurons, metabolic phenotyping and food intake were performed on C57BL/6J mice. RESULTS While mice given sugar-sweetened water do not gain significant weight, they do show subtle differences in body composition and caloric intake. When given sugar-sweetened water, mice show similar alterations to AgRP neuronal excitability as in high-fat diet obese models. Increased sugar consumption also primes mice for increased caloric intake and weight gain when given access to a HFD. CONCLUSIONS Our results show that elevated sucrose consumption increased activity of AgRP neurons and altered synaptic excitability. This may contribute to obesity in mice and humans with access to more palatable (HFD) diets.
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Affiliation(s)
- Austin C Korgan
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
| | - Klausen Oliveira-Abreu
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
- Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza, CE, Brazil
| | - Wei Wei
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
- Georgia State University, Atlanta, GA, USA
| | | | - Zoey J D Bridges
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
| | | | - Catherine C Kaczorowski
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, USA
- Neuroscience Program, Graduate School of Biomedical Science, Tufts University School of Medicine, Boston, MA, USA
| | - Kristen M S O'Connell
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA.
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, USA.
- Neuroscience Program, Graduate School of Biomedical Science, Tufts University School of Medicine, Boston, MA, USA.
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Ferrulli A, Terruzzi I, Senesi P, Succi M, Cannavaro D, Luzi L. Turning the clock forward: New pharmacological and non pharmacological targets for the treatment of obesity. Nutr Metab Cardiovasc Dis 2022; 32:1320-1334. [PMID: 35354547 DOI: 10.1016/j.numecd.2022.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/21/2022] [Accepted: 02/25/2022] [Indexed: 11/26/2022]
Abstract
AIMS Obesity and its main metabolic complication, type 2 diabetes, have attained the status of a global pandemic; there is need for novel strategies aimed at treating obesity and preventing the development of diabetes. A healthy diet and exercise are basic for treatment of obesity but often not enough. Pharmacotherapy can be helpful in maintaining compliance, ameliorating obesity-related health risks, and improving quality of life. In the last two decades, the knowledge of central and peripheral mechanisms underlying homeostatic and hedonic aspects of food intake has significantly increased. Dysregulation of one or more of these components could lead to obesity. DATA SYNTHESIS In order to better understand how potential innovative treatment options can affect obesity, homeostatic and reward mechanisms that regulate energy balance has been firstly illustrated. Then, an overview of potential therapeutic targets for obesity, distinguished according to the level of regulation of feeding behavior, has been provided. Moreover, several non-drug therapies have been recently tested in obesity, such as non-invasive neurostimulation: Transcranial Magnetic Stimulation or Transcranial Direct Current Stimulation. All of them are promising for obesity treatment and are almost devoid of side effects, constituting a potential resource for the prevention of metabolic diseases. CONCLUSIONS The plethora of current anti-obesity therapies creates the unique challenge for physicians to customize the intervention, according to the specific obesity characteristics and the intervention side effect profiles; moreover, it allows multimodal approaches addressed to treat obesity and metabolic adaptation with complementary mechanisms.
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Affiliation(s)
- Anna Ferrulli
- Department of Endocrinology, Nutrition and Metabolic Diseases, IRCCS MultiMedica, Sesto San Giovanni, MI, Italy; Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Ileana Terruzzi
- Department of Endocrinology, Nutrition and Metabolic Diseases, IRCCS MultiMedica, Sesto San Giovanni, MI, Italy; Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Pamela Senesi
- Department of Endocrinology, Nutrition and Metabolic Diseases, IRCCS MultiMedica, Sesto San Giovanni, MI, Italy; Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Massimiliano Succi
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Daniele Cannavaro
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Livio Luzi
- Department of Endocrinology, Nutrition and Metabolic Diseases, IRCCS MultiMedica, Sesto San Giovanni, MI, Italy; Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.
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Liang Y, Yin W, Yin Y, Zhang W. Ghrelin Based Therapy of Metabolic Diseases. Curr Med Chem 2021; 28:2565-2576. [PMID: 32538716 PMCID: PMC11213490 DOI: 10.2174/0929867327666200615152804] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/04/2020] [Accepted: 05/18/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Ghrelin, a unique 28 amino acid peptide hormone secreted by the gastric X/A like cells, is an endogenous ligand of the growth hormone secretagogue receptor (GHSR). Ghrelin-GHSR signaling has been found to exert various physiological functions, including stimulation of appetite, regulation of body weight, lipid and glucose metabolism, and increase of gut motility and secretion. This system is thus critical for energy homeostasis. OBJECTIVE The objective of this review is to highlight the strategies of ghrelin-GHSR based intervention for therapy of obesity and its related metabolic diseases. RESULTS Therapeutic strategies of metabolic disorders targeting the ghrelin-GHSR pathway involve neutralization of circulating ghrelin by antibodies and RNA spiegelmers, antagonism of ghrelin receptor by its antagonists and inverse agonists, inhibition of ghrelin O-acyltransferase (GOAT), as well as potential pharmacological approach to decrease ghrelin synthesis and secretion. CONCLUSION Various compounds targeting the ghrelin-GHSR system have shown promising efficacy for the intervention of obesity and relevant metabolic disorders in animals and in vitro. Further clinical trials to validate their efficacy in human beings are urgently needed.
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Affiliation(s)
- Yuan Liang
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Wenzhen Yin
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yue Yin
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Weizhen Zhang
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI 48109-0346, USA
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4
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Gortan Cappellari G, Barazzoni R. Ghrelin forms in the modulation of energy balance and metabolism. Eat Weight Disord 2019; 24:997-1013. [PMID: 30353455 DOI: 10.1007/s40519-018-0599-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/16/2018] [Indexed: 02/06/2023] Open
Abstract
Ghrelin is a gastric hormone circulating in acylated (AG) and unacylated (UnAG) forms. This narrative review aims at presenting current emerging knowledge on the impact of ghrelin forms on energy balance and metabolism. AG represents ~ 10% of total plasma ghrelin, has an appetite-stimulating effect and is the only form for which a receptor has been identified. Moreover, other metabolic AG-induced effects have been reported, including the modulation of glucose homeostasis with stimulation of liver gluconeogenesis, the increase of fat mass and the improvement of skeletal muscle mitochondrial function. On the other hand, UnAG has no orexigenic effects, however recent reports have shown that it is directly involved in the modulation of skeletal muscle energy metabolism by improving a cluster of interlinked functions including mitochondrial redox activities, tissue inflammation and insulin signalling and action. These findings are in agreement with human studies which show that UnAG circulating levels are positively associated with insulin sensitivity both in metabolic syndrome patients and in a large cohort from the general population. Moreover, ghrelin acylation is regulated by a nutrient sensor mechanism, specifically set on fatty acids availability. These recent findings consistently point towards a novel independent role of UnAG as a regulator of muscle metabolic pathways maintaining energy status and tissue anabolism. While a specific receptor for UnAG still needs to be identified, recent evidence strongly supports the hypothesis that the modulation of ghrelin-related molecular pathways, including those involved in its acylation, may be a potential novel target in the treatment of metabolic derangements in disease states characterized by metabolic and nutritional complications.Level of evidence Level V, narrative review.
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Affiliation(s)
- Gianluca Gortan Cappellari
- Department of Medical, Surgical and Health Sciences, University of Trieste, Strada di Fiume, 447, 34149, Trieste, Italy.
| | - Rocco Barazzoni
- Department of Medical, Surgical and Health Sciences, University of Trieste, Strada di Fiume, 447, 34149, Trieste, Italy.
- Azienda Sanitaria Universitaria Integrata di Trieste (ASUITS), Trieste, Italy.
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Abstract
PURPOSE OF REVIEW Obesity is affecting over 600 million adults worldwide and has numerous negative effects on health. Since ghrelin positively regulates food intake and body weight, targeting its signaling to induce weight loss under conditions of obesity seems promising. Thus, the present work reviews and discusses different possibilities to alter ghrelin signaling. RECENT FINDINGS Ghrelin signaling can be altered by RNA Spiegelmers, GHSR/Fc, ghrelin-O-acyltransferase inhibitors as well as antagonists, and inverse agonists of the ghrelin receptor. PF-05190457 is the first inverse agonist of the ghrelin receptor tested in humans shown to inhibit growth hormone secretion, gastric emptying, and reduce postprandial glucose levels. Effects on body weight were not examined. Although various highly promising agents targeting ghrelin signaling exist, so far, they were mostly only tested in vitro or in animal models. Further research in humans is thus needed to further assess the effects of ghrelin antagonism on body weight especially under conditions of obesity.
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Affiliation(s)
- Martha A Schalla
- Charité Center for Internal Medicine and Dermatology, Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine; Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine; Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tübingen, Tübingen, Germany.
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Colldén G, Tschöp MH, Müller TD. Therapeutic Potential of Targeting the Ghrelin Pathway. Int J Mol Sci 2017; 18:ijms18040798. [PMID: 28398233 PMCID: PMC5412382 DOI: 10.3390/ijms18040798] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/03/2017] [Accepted: 04/06/2017] [Indexed: 02/07/2023] Open
Abstract
Ghrelin was discovered in 1999 as the endogenous ligand of the growth-hormone secretagogue receptor 1a (GHSR1a). Since then, ghrelin has been found to exert a plethora of physiological effects that go far beyond its initial characterization as a growth hormone (GH) secretagogue. Among the numerous well-established effects of ghrelin are the stimulation of appetite and lipid accumulation, the modulation of immunity and inflammation, the stimulation of gastric motility, the improvement of cardiac performance, the modulation of stress, anxiety, taste sensation and reward-seeking behavior, as well as the regulation of glucose metabolism and thermogenesis. Due to a variety of beneficial effects on systems’ metabolism, pharmacological targeting of the endogenous ghrelin system is widely considered a valuable approach to treat metabolic complications, such as chronic inflammation, gastroparesis or cancer-associated anorexia and cachexia. The aim of this review is to discuss and highlight the broad pharmacological potential of ghrelin pathway modulation for the treatment of anorexia, cachexia, sarcopenia, cardiopathy, neurodegenerative disorders, renal and pulmonary disease, gastrointestinal (GI) disorders, inflammatory disorders and metabolic syndrome.
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Affiliation(s)
- Gustav Colldén
- Institute for Diabetes and Obesity & Helmholtz Diabetes Center, Helmholtz Zentrum München German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany.
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity & Helmholtz Diabetes Center, Helmholtz Zentrum München German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany.
- Division of Metabolic Diseases, Department of Medicine, Technische Universität München, 80333 Munich, Germany.
| | - Timo D Müller
- Institute for Diabetes and Obesity & Helmholtz Diabetes Center, Helmholtz Zentrum München German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany.
- Institute for Diabetes and Obesity (IDO), Business Campus Garching-Hochbrück, Parkring 13, 85748 Garching, Germany.
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Alamri BN, Shin K, Chappe V, Anini Y. The role of ghrelin in the regulation of glucose homeostasis. Horm Mol Biol Clin Investig 2017; 26:3-11. [PMID: 27235674 DOI: 10.1515/hmbci-2016-0018] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 05/08/2016] [Indexed: 12/16/2022]
Abstract
Ghrelin is a 28-amino acid (aa) stomach-derived peptide discovered in 1999 as the endogenous ligand for growth hormone secretagogue-receptor (GHS-R). Ghrelin-producing cells constitute a distinct group of endocrine cells dispersed throughout the gastric mucosa and to a lesser extent in the small intestine and the endocrine pancreas. Ghrelin plasma levels rise during fasting and chronic caloric restriction to stimulate food intake and fat storage and to prevent life-threatening falls in blood glucose. Plasma ghrelin levels decrease after a meal is consumed and in conditions of energy surplus (such as obesity). Ghrelin has emerged as a key player in the regulation of appetite and energy homeostasis. Ghrelin achieves these functions through binding the ghrelin receptor GHS-R in appetite-regulating neurons and in peripheral metabolic organs including the endocrine pancreas. Ghrelin levels are negatively correlated with body mass index (BMI) and insulin resistance. In addition, ghrelin secretion is impaired in obesity and insulin resistance. Several studies highlight an important role for ghrelin in glucose homeostasis. Genetic, immunological, and pharmacological blockade of ghrelin signaling resulted in improved glucose tolerance and insulin sensitivity. Furthermore, exogenous ghrelin administration was shown to decrease glucose-induced insulin release and increase glucose level in both humans and rodents. GHS-R was shown to be expressed in pancreatic β-cells and ghrelin suppressed insulin release via a Ca2+-mediated pathway. In this review, we provide a detailed summary of recent advances in the field that focuses on the role of insulin and insulin resistance in the regulation of ghrelin secretion and on the role of ghrelin in glucose-stimulated insulin secretion (GSIS).
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Jura M, Kozak LP. Obesity and related consequences to ageing. AGE (DORDRECHT, NETHERLANDS) 2016; 38:23. [PMID: 26846415 PMCID: PMC5005878 DOI: 10.1007/s11357-016-9884-3] [Citation(s) in RCA: 245] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 01/26/2016] [Indexed: 04/17/2023]
Abstract
Obesity has become a major public health problem. Given the current increase in life expectancy, the prevalence of obesity also raises steadily among older age groups. The increase in life expectancy is often accompanied with additional years of susceptibility to chronic ill health associated with obesity in the elderly. Both obesity and ageing are conditions leading to serious health problems and increased risk for disease and death. Ageing is associated with an increase in abdominal obesity, a major contributor to insulin resistance and the metabolic syndrome. Obesity in the elderly is thus a serious concern and comprehension of the key mechanisms of ageing and age-related diseases has become a necessary matter. Here, we aimed to identify similarities underlying mechanisms related to both obesity and ageing. We bring together evidence that age-related changes in body fat distribution and metabolism might be key factors of a vicious cycle that can accelerate the ageing process and onset of age-related diseases.
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Affiliation(s)
- Magdalena Jura
- Institute of Animal Reproduction and Food Research, Polish Academy of Science, ul. Tuwima 10, 10-748, Olsztyn, Poland.
| | - Leslie P Kozak
- Institute of Animal Reproduction and Food Research, Polish Academy of Science, ul. Tuwima 10, 10-748, Olsztyn, Poland.
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