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Hill TG, Hill DJ. The Importance of Intra-Islet Communication in the Function and Plasticity of the Islets of Langerhans during Health and Diabetes. Int J Mol Sci 2024; 25:4070. [PMID: 38612880 PMCID: PMC11012451 DOI: 10.3390/ijms25074070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/27/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Islets of Langerhans are anatomically dispersed within the pancreas and exhibit regulatory coordination between islets in response to nutritional and inflammatory stimuli. However, within individual islets, there is also multi-faceted coordination of function between individual beta-cells, and between beta-cells and other endocrine and vascular cell types. This is mediated partly through circulatory feedback of the major secreted hormones, insulin and glucagon, but also by autocrine and paracrine actions within the islet by a range of other secreted products, including somatostatin, urocortin 3, serotonin, glucagon-like peptide-1, acetylcholine, and ghrelin. Their availability can be modulated within the islet by pericyte-mediated regulation of microvascular blood flow. Within the islet, both endocrine progenitor cells and the ability of endocrine cells to trans-differentiate between phenotypes can alter endocrine cell mass to adapt to changed metabolic circumstances, regulated by the within-islet trophic environment. Optimal islet function is precariously balanced due to the high metabolic rate required by beta-cells to synthesize and secrete insulin, and they are susceptible to oxidative and endoplasmic reticular stress in the face of high metabolic demand. Resulting changes in paracrine dynamics within the islets can contribute to the emergence of Types 1, 2 and gestational diabetes.
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Affiliation(s)
- Thomas G. Hill
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - David J. Hill
- Lawson Health Research Institute, St. Joseph’s Health Care, London, ON N6A 4V2, Canada;
- Departments of Medicine, Physiology and Pharmacology, Western University, London, ON N6A 3K7, Canada
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Bany Bakar R, Reimann F, Gribble FM. The intestine as an endocrine organ and the role of gut hormones in metabolic regulation. Nat Rev Gastroenterol Hepatol 2023; 20:784-796. [PMID: 37626258 DOI: 10.1038/s41575-023-00830-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/25/2023] [Indexed: 08/27/2023]
Abstract
Gut hormones orchestrate pivotal physiological processes in multiple metabolically active tissues, including the pancreas, liver, adipose tissue, gut and central nervous system, making them attractive therapeutic targets in the treatment of obesity and type 2 diabetes mellitus. Most gut hormones are derived from enteroendocrine cells, but bioactive peptides that are derived from other intestinal epithelial cell types have also been implicated in metabolic regulation and can be considered gut hormones. A deeper understanding of the complex inter-organ crosstalk mediated by the intestinal endocrine system is a prerequisite for designing more effective drugs that are based on or target gut hormones and their receptors, and extending their therapeutic potential beyond obesity and diabetes mellitus. In this Review, we present an overview of gut hormones that are involved in the regulation of metabolism and discuss their action in the gastrointestinal system and beyond.
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Affiliation(s)
- Rula Bany Bakar
- Wellcome Trust-MRC Institute of Metabolic Science Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Frank Reimann
- Wellcome Trust-MRC Institute of Metabolic Science Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Fiona M Gribble
- Wellcome Trust-MRC Institute of Metabolic Science Metabolic Research Laboratories, University of Cambridge, Cambridge, UK.
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3
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Inceu AI, Neag MA, Craciun AE, Buzoianu AD. Gut Molecules in Cardiometabolic Diseases: The Mechanisms behind the Story. Int J Mol Sci 2023; 24:ijms24043385. [PMID: 36834796 PMCID: PMC9965280 DOI: 10.3390/ijms24043385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
Atherosclerotic cardiovascular disease is the most common cause of morbidity and mortality worldwide. Diabetes mellitus increases cardiovascular risk. Heart failure and atrial fibrillation are associated comorbidities that share the main cardiovascular risk factors. The use of incretin-based therapies promoted the idea that activation of alternative signaling pathways is effective in reducing the risk of atherosclerosis and heart failure. Gut-derived molecules, gut hormones, and gut microbiota metabolites showed both positive and detrimental effects in cardiometabolic disorders. Although inflammation plays a key role in cardiometabolic disorders, additional intracellular signaling pathways are involved and could explain the observed effects. Revealing the involved molecular mechanisms could provide novel therapeutic strategies and a better understanding of the relationship between the gut, metabolic syndrome, and cardiovascular diseases.
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Affiliation(s)
- Andreea-Ioana Inceu
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Iuliu Hatieganu University of Medicine and Pharmacy, 400337 Cluj-Napoca, Romania
| | - Maria-Adriana Neag
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Iuliu Hatieganu University of Medicine and Pharmacy, 400337 Cluj-Napoca, Romania
- Correspondence:
| | - Anca-Elena Craciun
- Department of Diabetes, and Nutrition Diseases, Iuliu Hatieganu University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania
| | - Anca-Dana Buzoianu
- Department of Pharmacology, Toxicology and Clinical Pharmacology, Iuliu Hatieganu University of Medicine and Pharmacy, 400337 Cluj-Napoca, Romania
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Villarreal D, Pradhan G, Zhou Y, Xue B, Sun Y. Diverse and Complementary Effects of Ghrelin and Obestatin. Biomolecules 2022; 12:biom12040517. [PMID: 35454106 PMCID: PMC9028691 DOI: 10.3390/biom12040517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 03/21/2022] [Accepted: 03/25/2022] [Indexed: 02/06/2023] Open
Abstract
Ghrelin and obestatin are two “sibling proteins” encoded by the same preproghrelin gene but possess an array of diverse and complex functions. While there are ample literature documenting ghrelin’s functions, the roles of obestatin are less clear and controversial. Ghrelin and obestatin have been perceived to be antagonistic initially; however, recent studies challenge this dogma. While they have opposing effects in some systems, they function synergistically in other systems, with many functions remaining debatable. In this review, we discuss their functional relationship under three “C” categories, namely complex, complementary, and contradictory. Their functions in food intake, weight regulation, hydration, gastrointestinal motility, inflammation, and insulin secretion are complex. Their functions in pancreatic beta cells, cardiovascular, muscle, neuroprotection, cancer, and digestive system are complementary. Their functions in white adipose tissue, thermogenesis, and sleep regulation are contradictory. Overall, this review accumulates the multifaceted functions of ghrelin and obestatin under both physiological and pathological conditions, with the intent of contributing to a better understanding of these two important gut hormones.
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Affiliation(s)
- Daniel Villarreal
- Department of Nutrition, Texas A & M University, College Station, TX 77843, USA;
| | - Geetali Pradhan
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA;
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yu Zhou
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao 266071, China;
| | - Bingzhong Xue
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA;
| | - Yuxiang Sun
- Department of Nutrition, Texas A & M University, College Station, TX 77843, USA;
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA;
- Correspondence: ; Tel.: +1-979-862-9143
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Liu XY, Zhang N, Zhang SX, Xu P. Potential new therapeutic target for Alzheimer's disease: Glucagon-like peptide-1. Eur J Neurosci 2021; 54:7749-7769. [PMID: 34676939 DOI: 10.1111/ejn.15502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022]
Abstract
Increasing evidence shows a close relationship between Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM). Recently, glucagon-like peptide-1 (GLP-1), a gut incretin hormone, has become a well-established treatment for T2DM and is likely to be involved in treating cognitive impairment. In this mini review, the similarities between AD and T2DM are summarised with the main focus on GLP-1-based therapeutics in AD.
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Affiliation(s)
- Xiao-Yu Liu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Ni Zhang
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Sheng-Xiao Zhang
- Department of Rheumatology, The Second Hospital of Shanxi Medical University, Taiyuan, China.,Key laboratory of Cellular Physiology, Shanxi Medical University, Ministry of Education, Shanxi, China
| | - Ping Xu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
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Napolitano T, Avolio F, Silvano S, Forcisi S, Pfeifer A, Vieira A, Navarro-Sanz S, Friano ME, Ayachi C, Garrido-Utrilla A, Atlija J, Hadzic B, Becam J, Sousa-De-Veiga A, Plaisant MD, Balaji S, Pisani DF, Mondin M, Schmitt-Kopplin P, Amri EZ, Collombat P. Gfi1 Loss Protects against Two Models of Induced Diabetes. Cells 2021; 10:cells10112805. [PMID: 34831029 PMCID: PMC8616283 DOI: 10.3390/cells10112805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/07/2021] [Accepted: 10/14/2021] [Indexed: 12/29/2022] Open
Abstract
Background: Although several approaches have revealed much about individual factors that regulate pancreatic development, we have yet to fully understand their complicated interplay during pancreas morphogenesis. Gfi1 is transcription factor specifically expressed in pancreatic acinar cells, whose role in pancreas cells fate identity and specification is still elusive. Methods: In order to gain further insight into the function of this factor in the pancreas, we generated animals deficient for Gfi1 specifically in the pancreas. Gfi1 conditional knockout animals were phenotypically characterized by immunohistochemistry, RT-qPCR, and RNA scope. To assess the role of Gfi1 in the pathogenesis of diabetes, we challenged Gfi1-deficient mice with two models of induced hyperglycemia: long-term high-fat/high-sugar feeding and streptozotocin injections. Results: Interestingly, mutant mice did not show any obvious deleterious phenotype. However, in depth analyses demonstrated a significant decrease in pancreatic amylase expression, leading to a diminution in intestinal carbohydrates processing and thus glucose absorption. In fact, Gfi1-deficient mice were found resistant to diet-induced hyperglycemia, appearing normoglycemic even after long-term high-fat/high-sugar diet. Another feature observed in mutant acinar cells was the misexpression of ghrelin, a hormone previously suggested to exhibit anti-apoptotic effects on β-cells in vitro. Impressively, Gfi1 mutant mice were found to be resistant to the cytotoxic and diabetogenic effects of high-dose streptozotocin administrations, displaying a negligible loss of β-cells and an imperturbable normoglycemia. Conclusions: Together, these results demonstrate that Gfi1 could turn to be extremely valuable for the development of new therapies and could thus open new research avenues in the context of diabetes research.
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Affiliation(s)
- Tiziana Napolitano
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | - Fabio Avolio
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark;
| | - Serena Silvano
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | - Sara Forcisi
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, German Research Center for Environment Health, 85764 Neuherberg, Germany; (S.F.); (P.S.-K.)
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Anja Pfeifer
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | - Andhira Vieira
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | | | - Marika Elsa Friano
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | - Chaïma Ayachi
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | - Anna Garrido-Utrilla
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | | | - Biljana Hadzic
- Pediatric Oncology & Hematology Department, Centre Hospitalier Universitaire de Nice, Hopital Archet 2, 06202 Nice, France;
| | - Jérôme Becam
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | - Anette Sousa-De-Veiga
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | - Magali Dodille Plaisant
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | | | - Didier F. Pisani
- Medicine Faculty, Université Côte d’Azur, CNRS, LP2M, 06003 Nice, France;
| | - Magali Mondin
- Pôle Imagerie Photonique, Bordeaux Imaging Center, Université de Bordeaux, UMS 3420 CNRS-US4 Inserm, 33076 Bordeaux, France;
| | - Philippe Schmitt-Kopplin
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, German Research Center for Environment Health, 85764 Neuherberg, Germany; (S.F.); (P.S.-K.)
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Ez-Zoubir Amri
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
| | - Patrick Collombat
- Faculté des Sciences, Université Côte d’Azur, CNRS, Inserm, iBV, Parc Valrose, 06108 Nice, France; (T.N.); (S.S.); (A.P.); (A.V.); (M.E.F.); (C.A.); (A.G.-U.); (J.B.); (A.S.-D.-V.); (M.D.P.); (E.-Z.A.)
- Correspondence:
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Özcan B, Delhanty PJD, Huisman M, Visser JA, Neggers SJ, van der Lely AJ. Overweight and obesity in type 1 diabetes is not associated with higher ghrelin concentrations. Diabetol Metab Syndr 2021; 13:79. [PMID: 34294136 PMCID: PMC8296697 DOI: 10.1186/s13098-021-00699-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/09/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Several studies have demonstrated suppressed levels of acylated (AG) and unacylated ghrelin (UAG) in patients with type 2 diabetes. However, the role of these hormones in type 1 diabetes has not been extensively studied. This study assessed the relationship between AG and UAG levels and body composition in patients with type 1 diabetes. METHODS We selected eighteen patients with type 1 diabetes and divided them into two groups: non-obese (BMI < 25 kg/m2) and overweight (BMI ≥ 25 kg/m2). Demographics, parameters of body composition and serum parameters including AG and UAG, were assessed. RESULTS The patients with a BMI ≥ 25 kg/m2 were older and had a longer duration of diabetes. AG and UAG levels were not significantly different between non-obese and overweight groups (mean AG non-obese ± SD: 44.5 ± 29.4 pg/ml and mean UAG non-obese 42.4 ± 20.7 pg/ml vs mean AG overweight ± SD: 46.1 ± 29.6 pg/ml and mean UAG overweight 47.2 ± 18.2 pg/ml). AG/UAG ratios did not discriminate between these groups. There was a positive association of insuline dose/kg bodyweight with BMI (r2 = 0.45, p = 0.002). CONCLUSIONS Surprisingly, unlike non-diabetics and in T2D, we did not observe a difference in plasma levels of AG and UAG between normal weight and overweight adult type 1 diabetics. However, we did observe a positive correlation between BMI and insuline dose/kg bodyweight, suggesting that exogenous insulin is more important than the ghrelin system in the development of obesity in type 1 diabetes.
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Affiliation(s)
- Behiye Özcan
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
| | - Patric J D Delhanty
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Martin Huisman
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Jenny A Visser
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Sebastian J Neggers
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Aart Jan van der Lely
- Departments of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
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[Body composition, mineral metabolism, and endocrine function of adipose tissue: influence of a nutritional supplement of propolis]. NUTR HOSP 2021; 38:585-591. [PMID: 33666089 DOI: 10.20960/nh.03438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Introduction Introduction: propolis and its components influence lipid metabolism; however, its effect on body composition and mineral metabolism remains unknown. Objectives: to determine the effect of natural propolis supplementation on body composition, mineral metabolism, and the endocrine function of adipose tissue. Material and methods: twenty albino male Wistar rats (8 weeks old) were divided into two groups of 10 animals each. The rats were fed two different types of diet for 90 days: a standard diet for the control group (group C) and the same standard diet + 2 % propolis (group P). Thyroid hormones, ghrelin, leptin, adiponectin and insulin, non-esterified fatty acids (NEFA) in plasma, body composition (lean mass, fat mass and body water), and mineral deposition in target organs (spleen, brain, heart, lungs, testicles, kidneys and femur) were assessed. Results: thyroid stimulating hormone (TSH), triiodothyronine (T3) and thyroxine (T4) did not show any differences after supplementation with propolis, while ghrelin and adiponectin decreased (p < 0.01 and p < 0.05, respectively) and insulin (p < 0.01), leptin (p < 0.05) and NEFA (p < 0.05) increased when 2 % propolis was supplied, while weight and body fat were reduced (p < 0.05) and lean mass increased. Lastly, the propolis supplement improves calcium deposition in the spleen, lungs, testes, and femur (p < 0.05). Conclusion: propolis supplementation of the diet (2 %) causes a decrease in the secretion of ghrelin and adiponectin, increasing the release of non-esterified fatty acids and the rate of insulin secretion. In addition, propolis supplementation induces an improvement in calcium deposition in target organs without affecting the rest of minerals, which improves body composition by inducing a reduction in weight and visceral adipose tissue, and improvement in lean mass.
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Kakiyama G, Marques D, Martin R, Takei H, Rodriguez-Agudo D, LaSalle SA, Hashiguchi T, Liu X, Green R, Erickson S, Gil G, Fuchs M, Suzuki M, Murai T, Nittono H, Hylemon PB, Zhou H, Pandak WM. Insulin resistance dysregulates CYP7B1 leading to oxysterol accumulation: a pathway for NAFL to NASH transition. J Lipid Res 2020; 61:1629-1644. [PMID: 33008924 DOI: 10.1194/jlr.ra120000924] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
NAFLD is an important public health issue closely associated with the pervasive epidemics of diabetes and obesity. Yet, despite NAFLD being among the most common of chronic liver diseases, the biological factors responsible for its transition from benign nonalcoholic fatty liver (NAFL) to NASH remain unclear. This lack of knowledge leads to a decreased ability to find relevant animal models, predict disease progression, or develop clinical treatments. In the current study, we used multiple mouse models of NAFLD, human correlation data, and selective gene overexpression of steroidogenic acute regulatory protein (StarD1) in mice to elucidate a plausible mechanistic pathway for promoting the transition from NAFL to NASH. We show that oxysterol 7α-hydroxylase (CYP7B1) controls the levels of intracellular regulatory oxysterols generated by the "acidic/alternative" pathway of cholesterol metabolism. Specifically, we report data showing that an inability to upregulate CYP7B1, in the setting of insulin resistance, results in the accumulation of toxic intracellular cholesterol metabolites that promote inflammation and hepatocyte injury. This metabolic pathway, initiated and exacerbated by insulin resistance, offers insight into approaches for the treatment of NAFLD.
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Affiliation(s)
- Genta Kakiyama
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA.
| | - Dalila Marques
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA
| | - Rebecca Martin
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA
| | - Hajime Takei
- Junshin Clinic Bile Acid Institute, Tokyo, Japan
| | - Daniel Rodriguez-Agudo
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA
| | - Sandra A LaSalle
- Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA
| | | | - Xiaoying Liu
- Department of Medicine, Northwestern University, Chicago, IL, USA
| | - Richard Green
- Department of Medicine, Northwestern University, Chicago, IL, USA
| | - Sandra Erickson
- School of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Gregorio Gil
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
| | - Michael Fuchs
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA
| | - Mitsuyoshi Suzuki
- Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Tsuyoshi Murai
- School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Hokkaido, Japan
| | | | - Phillip B Hylemon
- Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA; Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
| | - Huiping Zhou
- Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA; Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
| | - William M Pandak
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
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10
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Zhang D, Yu YJ, Xu FS, Yuan JH, Wang R, Zhang CS, Wang LX, Liu Y, Song LM, Liu JL, Dong J. Recombinant betatrophin (Angptl‑8/lipasin) ameliorates streptozotocin‑induced hyperglycemia and β‑cell destruction in neonatal rats. Mol Med Rep 2019; 20:4523-4532. [PMID: 31702044 PMCID: PMC6797976 DOI: 10.3892/mmr.2019.10719] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/09/2019] [Indexed: 12/16/2022] Open
Abstract
Betatrophin [also known as lipasin, angiopoietin‑like 8 (ANGPTL8), refeeding induced in fat and liver (RIFL), or hepatocellular carcinoma‑associated gene TD26], a 22‑kDa protein in the angiopoietin‑like family, is a liver‑derived hormone that promotes pancreatic β‑cell proliferation and lipid metabolism. The aim of the present study was to investigate the effect of recombinant betatrophin on β‑cell regeneration in a neonatal streptozotocin (STZ)‑induced diabetic rat model. One‑day‑old Wistar rats were injected with STZ (100 mg/kg), followed by intraperitoneal administration of betatrophin to the STZ‑injected rats for 6 days. Plasma glucose and body weight were monitored. On days 4 and 7, expression levels of pancreatic duodenal homeobox gene‑1 (PDX‑1), the Bax/B‑cell lymphoma‑2 (Bcl‑2) ratio and plasma insulin were assessed, and the β‑cell proliferation rate was determined. Pancreatic islet area and number were determined at 10 weeks. It was found that betatrophin treatment alleviated STZ‑induced hyperglycemia, elevated pancreatic expression levels of Bcl‑2, PDX‑1, plasma insulin levels and the β‑cell proliferation rate on days 4 and 7. Long‑term betatrophin treatment improved glucose tolerance, associated with improved plasma insulin levels and β‑cell mass. These results suggest that early administration of betatrophin promotes β‑cell proliferation in STZ‑induced diabetic neonates and prevents the development of diabetes in adults.
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Affiliation(s)
- Di Zhang
- Special Medicine Department, Medical College, Qingdao University, Qingdao, Shandong 266071, P.R. China
| | - Yan-Juan Yu
- Department of Endocrinology, The People's Hospital of Jiaozuo City, Jiaozuo, Henan 454150, P.R. China
| | - Feng-Sen Xu
- Department of Obstetrics, Qingdao Municipal Hospital, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266071, P.R. China
| | - Jun-Hua Yuan
- Special Medicine Department, Medical College, Qingdao University, Qingdao, Shandong 266071, P.R. China
| | - Rui Wang
- Special Medicine Department, Medical College, Qingdao University, Qingdao, Shandong 266071, P.R. China
| | - Cai-Shun Zhang
- Special Medicine Department, Medical College, Qingdao University, Qingdao, Shandong 266071, P.R. China
| | - Liu-Xin Wang
- Special Medicine Department, Medical College, Qingdao University, Qingdao, Shandong 266071, P.R. China
| | - Yuan Liu
- Special Medicine Department, Medical College, Qingdao University, Qingdao, Shandong 266071, P.R. China
| | - Li-Min Song
- Special Medicine Department, Medical College, Qingdao University, Qingdao, Shandong 266071, P.R. China
| | - Jun-Li Liu
- Fraser Laboratories for Diabetes Research, Department of Medicine, McGill University Health Center, McGill University, Montreal, QC H4A3J1, Canada
| | - Jing Dong
- Special Medicine Department, Medical College, Qingdao University, Qingdao, Shandong 266071, P.R. China
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11
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Gray SM, Page LC, Tong J. Ghrelin regulation of glucose metabolism. J Neuroendocrinol 2019; 31:e12705. [PMID: 30849212 PMCID: PMC6688917 DOI: 10.1111/jne.12705] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 12/14/2022]
Abstract
Ghrelin and its receptor, the growth hormone secretagogue receptor 1a (GHSR1a), are implicated in the regulation of glucose metabolism via direct actions in the pancreatic islet, as well as peripheral insulin-sensitive tissues and the brain. Although many studies have explored the role of ghrelin in glucose tolerance and insulin secretion, a complete mechanistic understanding remains to be clarified. This review highlights the local expression and function of ghrelin and GHSR1a in pancreatic islets and how this axis may modulate insulin secretion from pancreatic β-cells. Additionally, we discuss the effect of ghrelin on in vivo glucose metabolism in rodents and humans, as well as the metabolic circumstances under which the action of ghrelin may predominate.
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Affiliation(s)
- Sarah. M. Gray
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701
| | - Laura C. Page
- Division of Endocrinology, Department of Pediatrics, Duke University, Durham, NC 27701
| | - Jenny Tong
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701
- Division of Endocrinology, Department of Pediatrics, Duke University, Durham, NC 27701
- Division of Endocrinology, Metabolism, and Nutrition, Department of Medicine, Duke University, Durham, NC 27701
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12
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Abstract
Type 1 diabetes is a disease characterized by the destruction of insulin-secreting β-cells in the pancreas. Individuals are treated for this disease with lifelong insulin replacement. However, one attractive treatment possibility is to reprogram an individual’s endogenous cells to acquire the ability to secrete insulin, essentially replacing destroyed β-cells. Herein, we review the literature on the topic of reprogramming endodermal cells to produce insulin.
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Affiliation(s)
- Wendy M McKimpson
- Department of Medicine (Endocrinology), Columbia University, New York, New York
| | - Domenico Accili
- Department of Medicine (Endocrinology), Columbia University, New York, New York
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13
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Sakata N, Yoshimatsu G, Kodama S. Development and Characteristics of Pancreatic Epsilon Cells. Int J Mol Sci 2019; 20:ijms20081867. [PMID: 31014006 PMCID: PMC6514973 DOI: 10.3390/ijms20081867] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 04/11/2019] [Accepted: 04/12/2019] [Indexed: 12/19/2022] Open
Abstract
Pancreatic endocrine cells expressing the ghrelin gene and producing the ghrelin hormone were first identified in 2002. These cells, named ε cells, were recognized as the fifth type of endocrine cells. Differentiation of ε cells is induced by various transcription factors, including Nk2 homeobox 2, paired box proteins Pax-4 and Pax6, and the aristaless-related homeobox. Ghrelin is generally considered to be a "hunger hormone" that stimulates the appetite and is produced mainly by the stomach. Although the population of ε cells is small in adults, they play important roles in regulating other endocrine cells, especially β cells, by releasing ghrelin. However, the roles of ghrelin in β cells are complex. Ghrelin contributes to increased blood glucose levels by suppressing insulin release from β cells and is also involved in the growth and proliferation of β cells and the prevention of β cell apoptosis. Despite increasing evidence and clarification of the mechanisms of ε cells over the last 20 years, many questions remain to be answered. In this review, we present the current evidence for the participation of ε cells in differentiation and clarify their characteristics by focusing on the roles of ghrelin.
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Affiliation(s)
- Naoaki Sakata
- Department of Regenerative Medicine and Transplantation, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan.
- Center for Regenerative Medicine, Fukuoka University Hospital, Fukuoka 814-0180, Japan.
| | - Gumpei Yoshimatsu
- Department of Regenerative Medicine and Transplantation, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan.
- Center for Regenerative Medicine, Fukuoka University Hospital, Fukuoka 814-0180, Japan.
| | - Shohta Kodama
- Department of Regenerative Medicine and Transplantation, Faculty of Medicine, Fukuoka University, Fukuoka 814-0180, Japan.
- Center for Regenerative Medicine, Fukuoka University Hospital, Fukuoka 814-0180, Japan.
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14
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Napolitano T, Silvano S, Vieira A, Balaji S, Garrido-Utrilla A, Friano ME, Atlija J, Collombat P. Role of ghrelin in pancreatic development and function. Diabetes Obes Metab 2018; 20 Suppl 2:3-10. [PMID: 30230184 DOI: 10.1111/dom.13385] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/23/2018] [Accepted: 05/25/2018] [Indexed: 11/28/2022]
Abstract
Ghrelin is a gastric peptide with anabolic functions. It acutely stimulates growth hormone (GH) secretion from the anterior pituitary glands and modulates hypothalamic circuits that control food intake and energy expenditure. Besides its central activity, ghrelin is also involved in the regulation of pancreatic development and physiology. Particularly, several studies highlighted the ability of ghrelin to sustain β-cell viability and proliferation. Furthermore, ghrelin seems to exert inhibitory effects on pancreatic acinar and endocrine secretory functions. Due to its pleiotropic activity on energy metabolism, ghrelin has become a topic of great interest for experimental research focused on type II diabetes and obesity. The aim of this review is to illustrate the complex and not fully understood interplay between ghrelin, pancreas and glucose homeostasis.
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Affiliation(s)
- Tiziana Napolitano
- Inserm, CNRS, iBV, University of Nice Sophia Antipolis, Nice, France
- iBV, Institut de Biologie Valrose, Centre de Biochimie, University of Nice Sophia Antipolis, Nice Cedex 2, France
| | - Serena Silvano
- Inserm, CNRS, iBV, University of Nice Sophia Antipolis, Nice, France
- iBV, Institut de Biologie Valrose, Centre de Biochimie, University of Nice Sophia Antipolis, Nice Cedex 2, France
| | - Andhira Vieira
- Inserm, CNRS, iBV, University of Nice Sophia Antipolis, Nice, France
- iBV, Institut de Biologie Valrose, Centre de Biochimie, University of Nice Sophia Antipolis, Nice Cedex 2, France
| | - Shruti Balaji
- Inserm, CNRS, iBV, University of Nice Sophia Antipolis, Nice, France
- iBV, Institut de Biologie Valrose, Centre de Biochimie, University of Nice Sophia Antipolis, Nice Cedex 2, France
| | - Anna Garrido-Utrilla
- Inserm, CNRS, iBV, University of Nice Sophia Antipolis, Nice, France
- iBV, Institut de Biologie Valrose, Centre de Biochimie, University of Nice Sophia Antipolis, Nice Cedex 2, France
| | - Marika E Friano
- Inserm, CNRS, iBV, University of Nice Sophia Antipolis, Nice, France
- iBV, Institut de Biologie Valrose, Centre de Biochimie, University of Nice Sophia Antipolis, Nice Cedex 2, France
| | - Josipa Atlija
- Inserm, CNRS, iBV, University of Nice Sophia Antipolis, Nice, France
- iBV, Institut de Biologie Valrose, Centre de Biochimie, University of Nice Sophia Antipolis, Nice Cedex 2, France
| | - Patrick Collombat
- Inserm, CNRS, iBV, University of Nice Sophia Antipolis, Nice, France
- iBV, Institut de Biologie Valrose, Centre de Biochimie, University of Nice Sophia Antipolis, Nice Cedex 2, France
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15
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Poher AL, Tschöp MH, Müller TD. Ghrelin regulation of glucose metabolism. Peptides 2018; 100:236-242. [PMID: 29412824 PMCID: PMC5805851 DOI: 10.1016/j.peptides.2017.12.015] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/15/2017] [Accepted: 12/16/2017] [Indexed: 02/07/2023]
Abstract
The a 28-amino acid peptide ghrelin was discovered in 1999 as a growth hormone (GH) releasing peptide. Soon after its discovery, ghrelin was found to increase body weight and adiposity by acting on the hypothalamic melanocortinergic system. Subsequently, ghrelin was found to exert a series of metabolic effects, overall testifying ghrelin a pleiotropic nature of broad pharmacological interest. Ghrelin acts through the growth hormone secretagogue-receptor (GHS-R), a seven transmembrane G protein-coupled receptor with high expression in the anterior pituitary, pancreatic islets, thyroid gland, heart and various regions of the brain. Among ghrelins numerous metabolic effects are the most prominent the stimulation of appetite via activation of orexigenic hypothalamic neurocircuits and the food-intake independent stimulation of lipogenesis, which both together lead to an increase in body weight and adiposity. Ghrelin effects beyond the regulation of appetite and GH secretion include the regulation of gut motility, sleep-wake rhythm, taste sensation, reward seeking behaviour, and the regulation of glucose metabolism. The latter received recently increasing recognition because pharmacological inhibition of ghrelin signaling might be of therapeutic value to improve insuin resistance and type 2 diabetes. In this review we highlight the multifaceted nature of ghrelin and summarize its glucoregulatory action and discuss the pharmacological value of ghrelin pathway inhibition for the treatment of glucose intolerance and type 2 diabetes.
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Affiliation(s)
- Anne-Laure Poher
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center (HDC), Helmholtz Zentrum München and German National Diabetes Center (DZD), 85764, Neuherberg, Germany
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center (HDC), Helmholtz Zentrum München and German National Diabetes Center (DZD), 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 (HDC), Helmholtz Zentrum München and German National Diabetes Center (DZD), 85764, Neuherberg, Germany.
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16
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Baena-Nieto G, Lomas-Romero IM, Mateos RM, Leal-Cosme N, Perez-Arana G, Aguilar-Diosdado M, Segundo C, Lechuga-Sancho AM. Ghrelin mitigates β-cell mass loss during insulitis in an animal model of autoimmune diabetes mellitus, the BioBreeding/Worcester rat. Diabetes Metab Res Rev 2017; 33. [PMID: 27103341 DOI: 10.1002/dmrr.2813] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 03/06/2016] [Accepted: 04/07/2016] [Indexed: 12/24/2022]
Abstract
BACKGROUND Ghrelin is a peptide hormone with pleiotropic effects. It stimulates cell proliferation and inhibits apoptosis-mediated cell death. It prevents diabetes mellitus in several models of chemical, surgical and biological toxic insults to pancreas in both in vivo and in vitro models and promotes glucose-stimulated insulin secretion under cytotoxic conditions. It has not yet been tested in vivo in an autoimmune model of diabetes with a persistent insult to the β-cell. Given the immunomodulating effects of ghrelin and its trophic effects on β-cells, we hypothesized that ghrelin treatment during the early stages of insulitis would delay diabetes onset. METHODS BioBreeding/Worcester male rats received ghrelin (10 ng/kg/day) before insulitis development. Glucose metabolism was characterized by glucose and insulin tolerance tests. β-cell mass, islet area, islet number, β-cell clusters, proliferation and apoptosis and degree of insulitis were analysed by histomorphometry. A Kaplan-Meier survival curve was plotted and analysed applying the log-rank (Mantel-Cox) test. RESULTS Ghrelin treatment significantly reduced the probability of developing diabetes in our model (p < 0.0001). It decreased islet infiltration and partially prevented β-cell mass loss, enabling the maintenance of β-cell neogenesis and proliferation rates. Furthermore, ghrelin treatment did not induce any metabolic perturbations. CONCLUSIONS These findings support the hypothesis that ghrelin delays the development of autoimmune diabetes by attenuating insulitis and supporting β-cell mass. GENERAL SIGNIFICANCE Ghrelin promotes β-cell viability and function through diverse mechanisms that may have significant implications for diabetes prevention, therapy and also transplant success of both islets and complete pancreas. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Gloria Baena-Nieto
- Department of Endocrinology and Nutrition, Puerta del Mar University Hospital, Cadiz, Spain
- Research Unit, Puerta del Mar University Hospital, Cadiz, Spain
| | - Isabel M Lomas-Romero
- Research Unit, Puerta del Mar University Hospital, Cadiz, Spain
- Andalusian Cellular Reprogramming Laboratory, Sevilla, Spain
| | - Rosa M Mateos
- Research Unit, Puerta del Mar University Hospital, Cadiz, Spain
- Department of Biotechnology, Biomedicine and Public Health, Cadiz University Medical School, Cadiz, Spain
| | - Noelia Leal-Cosme
- Department of Child and Mother Health and Radiology, Cadiz University Medical School, Cadiz, Spain
| | | | | | - Carmen Segundo
- "Salus Infirmorum" Faculty of Nursing, Cadiz University, Cadiz, Spain
| | - Alfonso M Lechuga-Sancho
- Research Unit, Puerta del Mar University Hospital, Cadiz, Spain
- Department of Child and Mother Health and Radiology, Cadiz University Medical School, Cadiz, Spain
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17
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King A, Bowe J. Animal models for diabetes: Understanding the pathogenesis and finding new treatments. Biochem Pharmacol 2015; 99:1-10. [PMID: 26432954 DOI: 10.1016/j.bcp.2015.08.108] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/26/2015] [Indexed: 02/06/2023]
Abstract
Diabetes mellitus is a lifelong, metabolic disease that is characterised by an inability to maintain normal glucose homeostasis. There are several different forms of diabetes, however the two most common are Type 1 and Type 2 diabetes. Type 1 diabetes is caused by the autoimmune destruction of pancreatic beta cells and a subsequent lack of insulin production, whilst Type 2 diabetes is due to a combination of both insulin resistance and an inability of the beta cells to compensate adequately with increased insulin release. Animal models are increasingly being used to elucidate the mechanisms underlying both Type 1 and Type 2 diabetes as well as to identify and refine novel treatments. However, a wide range of different animal models are currently in use. The majority of these models are suited to addressing certain specific aspects of diabetes research, but may be of little use in other studies. All have pros and cons, and selecting an appropriate model for addressing a specific question is not always a trivial task and will influence the study results and their interpretation. Thus, as the number of available animal models increases it is important to consider the potential roles of these models in the many different aspects of diabetes research. This review gathers information on the currently used experimental animal models of both Type 1 and Type 2 diabetes and evaluates their advantages and disadvantages for research purposes and details the factors that should be taken into account in their use.
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Affiliation(s)
- Aileen King
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, Hodgkin Building 2nd Floor, Guy's Campus, King's College London, London SE1 1UL, United Kingdom.
| | - James Bowe
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, Hodgkin Building 2nd Floor, Guy's Campus, King's College London, London SE1 1UL, United Kingdom
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18
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Mosa RMH, Zhang Z, Shao R, Deng C, Chen J, Chen C. Implications of ghrelin and hexarelin in diabetes and diabetes-associated heart diseases. Endocrine 2015; 49:307-23. [PMID: 25645463 DOI: 10.1007/s12020-015-0531-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/12/2015] [Indexed: 02/07/2023]
Abstract
Ghrelin and its synthetic analog hexarelin are specific ligands of growth hormone secretagogue (GHS) receptor. GHS have strong growth hormone-releasing effect and other neuroendocrine activities such as stimulatory effects on prolactin and adrenocorticotropic hormone secretion. Recently, several studies have reported other beneficial functions of GHS that are independent of GH. Ghrelin and hexarelin, for examples, have been shown to exert GH-independent cardiovascular activity. Hexarelin has been reported to regulate peroxisome proliferator-activated receptor gamma (PPAR-γ) in macrophages and adipocytes. PPAR-γ is an important regulator of adipogenesis, lipid metabolism, and insulin sensitization. Ghrelin also shows protective effects on beta cells against lipotoxicity through activation of phosphatidylinositol-3 kinase/protein kinase B, c-Jun N-terminal kinase (JNK) inhibition, and nuclear exclusion of forkhead box protein O1. Acylated ghrelin (AG) and unacylated ghrelin (UAG) administration reduces glucose levels and increases insulin-producing beta cell number, and insulin secretion in pancreatectomized rats and in newborn rats treated with streptozotocin, suggesting a possible role of GHS in pancreatic regeneration. Therefore, the discovery of GHS has opened many new perspectives in endocrine, metabolic, and cardiovascular research areas, suggesting the possible therapeutic application in diabetes and diabetic complications especially diabetic cardiomyopathy. Here, we review the physiological roles of ghrelin and hexarelin in the protection and regeneration of beta cells and their roles in the regulation of insulin release, glucose, and fat metabolism and present their potential therapeutic effects in the treatment of diabetes and diabetic-associated heart diseases.
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19
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Zhang SR, Fan XM. Ghrelin-ghrelin O-acyltransferase system in the pathogenesis of nonalcoholic fatty liver disease. World J Gastroenterol 2015; 21:3214-3222. [PMID: 25805927 PMCID: PMC4363750 DOI: 10.3748/wjg.v21.i11.3214] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 12/29/2014] [Accepted: 01/30/2015] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is currently considered as the most common liver disease in Western countries, and is rapidly becoming a serious threat to public health worldwide. However, the underlying mechanisms leading to the development of NAFLD are still not fully understood. The ghrelin-ghrelin O-acyltransferase (GOAT) system has recently been found to play a crucial role in both the development of steatosis and its progression to nonalcoholic steatohepatitis. Ghrelin, the natural ligand of the growth hormone secretagogue receptor, is a 28-amino acid peptide possessing a unique acylation on the serine in position 3 catalyzed by GOAT. The ghrelin-GOAT system is involved in insulin resistance, lipid metabolism dysfunction, and inflammation, all of which play important roles in the pathogenesis of NAFLD. A better understanding of ghrelin-GOAT system biology led to the identification of its potential roles in NAFLD. Molecular targets modulating ghrelin-GOAT levels and the biologic effects are being studied, which provide a new insight into the pathogenesis of NAFLD. This review probes into the possible relationship between the ghrelin-GOAT system and NAFLD, and considers the potential mechanisms by which the ghrelin-GOAT system brings about insulin resistance and other aspects concerning NAFLD.
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20
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Müller TD, Nogueiras R, Andermann ML, Andrews ZB, Anker SD, Argente J, Batterham RL, Benoit SC, Bowers CY, Broglio F, Casanueva FF, D'Alessio D, Depoortere I, Geliebter A, Ghigo E, Cole PA, Cowley M, Cummings DE, Dagher A, Diano S, Dickson SL, Diéguez C, Granata R, Grill HJ, Grove K, Habegger KM, Heppner K, Heiman ML, Holsen L, Holst B, Inui A, Jansson JO, Kirchner H, Korbonits M, Laferrère B, LeRoux CW, Lopez M, Morin S, Nakazato M, Nass R, Perez-Tilve D, Pfluger PT, Schwartz TW, Seeley RJ, Sleeman M, Sun Y, Sussel L, Tong J, Thorner MO, van der Lely AJ, van der Ploeg LHT, Zigman JM, Kojima M, Kangawa K, Smith RG, Horvath T, Tschöp MH. Ghrelin. Mol Metab 2015; 4:437-60. [PMID: 26042199 PMCID: PMC4443295 DOI: 10.1016/j.molmet.2015.03.005] [Citation(s) in RCA: 696] [Impact Index Per Article: 77.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 03/11/2015] [Accepted: 03/11/2015] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism. SCOPE OF REVIEW In this review, we discuss the diverse biological functions of ghrelin, the regulation of its secretion, and address questions that still remain 15 years after its discovery. MAJOR CONCLUSIONS In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct areas including learning and memory, gut motility and gastric acid secretion, sleep/wake rhythm, reward seeking behavior, taste sensation and glucose metabolism.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, München, Germany
| | - R Nogueiras
- Department of Physiology, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas, University of Santiago de Compostela (CIMUS)-Instituto de Investigación Sanitaria (IDIS)-CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
| | - M L Andermann
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Z B Andrews
- Department of Physiology, Faculty of Medicine, Monash University, Melbourne, Victoria, Australia
| | - S D Anker
- Applied Cachexia Research, Department of Cardiology, Charité Universitätsmedizin Berlin, Germany
| | - J Argente
- Department of Pediatrics and Pediatric Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa, Madrid, Spain ; Department of Pediatrics, Universidad Autónoma de Madrid and CIBER Fisiopatología de la obesidad y nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - R L Batterham
- Centre for Obesity Research, University College London, London, United Kingdom
| | - S C Benoit
- Metabolic Disease Institute, Division of Endocrinology, Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - C Y Bowers
- Tulane University Health Sciences Center, Endocrinology and Metabolism Section, Peptide Research Section, New Orleans, LA, USA
| | - F Broglio
- Division of Endocrinology, Diabetes and Metabolism, Dept. of Medical Sciences, University of Torino, Torino, Italy
| | - F F Casanueva
- Department of Medicine, Santiago de Compostela University, Complejo Hospitalario Universitario de Santiago (CHUS), CIBER de Fisiopatologia Obesidad y Nutricion (CB06/03), Instituto Salud Carlos III, Santiago de Compostela, Spain
| | - D D'Alessio
- Duke Molecular Physiology Institute, Duke University, Durham, NC, USA
| | - I Depoortere
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - A Geliebter
- New York Obesity Nutrition Research Center, Department of Medicine, St Luke's-Roosevelt Hospital Center, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - E Ghigo
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - P A Cole
- Monash Obesity & Diabetes Institute, Monash University, Clayton, Victoria, Australia
| | - M Cowley
- Department of Physiology, Faculty of Medicine, Monash University, Melbourne, Victoria, Australia ; Monash Obesity & Diabetes Institute, Monash University, Clayton, Victoria, Australia
| | - D E Cummings
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - A Dagher
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - S Diano
- Dept of Neurobiology, Yale University School of Medicine, New Haven, CT, USA
| | - S L Dickson
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - C Diéguez
- Department of Physiology, School of Medicine, Instituto de Investigacion Sanitaria (IDIS), University of Santiago de Compostela, Spain
| | - R Granata
- Division of Endocrinology, Diabetes and Metabolism, Dept. of Medical Sciences, University of Torino, Torino, Italy
| | - H J Grill
- Department of Psychology, Institute of Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
| | - K Grove
- Department of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, USA
| | - K M Habegger
- Comprehensive Diabetes Center, University of Alabama School of Medicine, Birmingham, AL, USA
| | - K Heppner
- Division of Diabetes, Obesity, and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97006, USA
| | - M L Heiman
- NuMe Health, 1441 Canal Street, New Orleans, LA 70112, USA
| | - L Holsen
- Departments of Psychiatry and Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - B Holst
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen N, Denmark
| | - A Inui
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - J O Jansson
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - H Kirchner
- Medizinische Klinik I, Universitätsklinikum Schleswig-Holstein Campus Lübeck, Lübeck, Germany
| | - M Korbonits
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London, Queen Mary University of London, London, UK
| | - B Laferrère
- New York Obesity Research Center, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - C W LeRoux
- Diabetes Complications Research Centre, Conway Institute, University College Dublin, Ireland
| | - M Lopez
- Department of Physiology, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas, University of Santiago de Compostela (CIMUS)-Instituto de Investigación Sanitaria (IDIS)-CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
| | - S Morin
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, München, Germany
| | - M Nakazato
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Kiyotake, Miyazaki, Japan
| | - R Nass
- Division of Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - D Perez-Tilve
- Department of Internal Medicine, Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - P T Pfluger
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, München, Germany
| | - T W Schwartz
- Department of Neuroscience and Pharmacology, Laboratory for Molecular Pharmacology, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - R J Seeley
- Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - M Sleeman
- Department of Physiology, Faculty of Medicine, Monash University, Melbourne, Victoria, Australia
| | - Y Sun
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - L Sussel
- Department of Genetics and Development, Columbia University, New York, NY, USA
| | - J Tong
- Duke Molecular Physiology Institute, Duke University, Durham, NC, USA
| | - M O Thorner
- Division of Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - A J van der Lely
- Department of Medicine, Erasmus University MC, Rotterdam, The Netherlands
| | | | - J M Zigman
- Departments of Internal Medicine and Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - M Kojima
- Molecular Genetics, Institute of Life Science, Kurume University, Kurume, Japan
| | - K Kangawa
- National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - R G Smith
- The Scripps Research Institute, Florida Department of Metabolism & Aging, Jupiter, FL, USA
| | - T Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - M H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, München, Germany ; Division of Metabolic Diseases, Department of Medicine, Technical University Munich, Munich, Germany
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21
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Diaz-Ganete A, Baena-Nieto G, Lomas-Romero IM, Lopez-Acosta JF, Cozar-Castellano I, Medina F, Segundo C, Lechuga-Sancho AM. Ghrelin's Effects on Proinflammatory Cytokine Mediated Apoptosis and Their Impact on β-Cell Functionality. Int J Endocrinol 2015; 2015:235727. [PMID: 26257781 PMCID: PMC4519548 DOI: 10.1155/2015/235727] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 06/05/2015] [Accepted: 06/18/2015] [Indexed: 02/07/2023] Open
Abstract
Ghrelin is a peptidic hormone, which stimulates cell proliferation and inhibits apoptosis in several tissues, including pancreas. In preclinical stage of type 1 diabetes, proinflammatory cytokines generate a destructive environment for β-cells known as insulitis, which results in loss of β-cell mass and impaired insulin secretion, leading to diabetes. Our aim was to demonstrate that ghrelin could preserve β-cell viability, turnover rate, and insulin secretion acting as a counter balance of cytokines. In the present work we reproduced proinflammatory milieu found in insulitis stage by treating murine cell line INS-1E and rat islets with a cytokine cocktail including IL-1β, IFNγ, and TNFα and/or ghrelin. Several proteins involved in survival pathways (ERK 1/2 and Akt/PKB) and apoptosis (caspases and Bcl-2 protein family and endoplasmic reticulum stress markers) as well as insulin secretion were analyzed. Our results show that ghrelin alone has no remarkable effects on β-cells in basal conditions, but interestingly it activates cell survival pathways, downregulates apoptotic mediators and endoplasmic reticulum stress, and restores insulin secretion in response to glucose when beta-cells are cytokine-exposed. These data suggest a potential role of ghrelin in preventing or slowing down the transition from a preclinical to clinically established diabetes by ameliorating the effects of insulitis on β-cells.
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Affiliation(s)
| | - Gloria Baena-Nieto
- Research Unit, Puerta del Mar University Hospital, 11009 Cadiz, Spain
- Department of Endocrinology and Nutrition, Jerez de la Frontera General Hospital, 11407 Jerez de la Frontera, Spain
| | - Isabel M. Lomas-Romero
- Research Unit, Puerta del Mar University Hospital, 11009 Cadiz, Spain
- Andalusian Cellular Reprogramming Laboratory, 41092 Sevilla, Spain
| | - Jose Francisco Lopez-Acosta
- Research Unit, Puerta del Mar University Hospital, 11009 Cadiz, Spain
- Genetics and Molecular Biology Research Institute, University of Valladolid-CSIC, 47003 Valladolid, Spain
| | - Irene Cozar-Castellano
- Genetics and Molecular Biology Research Institute, University of Valladolid-CSIC, 47003 Valladolid, Spain
| | - Francisco Medina
- Research Unit, Puerta del Mar University Hospital, 11009 Cadiz, Spain
- Salus Infirmorum Faculty of Nursing, Cadiz University, 11001 Cadiz, Spain
| | - Carmen Segundo
- Research Unit, Puerta del Mar University Hospital, 11009 Cadiz, Spain
- Salus Infirmorum Faculty of Nursing, Cadiz University, 11001 Cadiz, Spain
- *Carmen Segundo: and
| | - Alfonso M. Lechuga-Sancho
- Research Unit, Puerta del Mar University Hospital, 11009 Cadiz, Spain
- Department of Maternal and Pediatric Medicine and Radiology, Pediatrics Unit, Puerta del Mar University Hospital, 11009 Cadiz, Spain
- *Alfonso M. Lechuga-Sancho:
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Affiliation(s)
- Rocco Barazzoni
- Internal Medicine, Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
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23
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Granata R, Settanni F, Trovato L, Gallo D, Gesmundo I, Nano R, Gallo MP, Bergandi L, Volante M, Alloatti G, Piemonti L, Leprince J, Papotti M, Vaudry H, Ong H, Ghigo E. RFamide peptides 43RFa and 26RFa both promote survival of pancreatic β-cells and human pancreatic islets but exert opposite effects on insulin secretion. Diabetes 2014; 63:2380-93. [PMID: 24622796 DOI: 10.2337/db13-1522] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
RFamide peptides 43RFa and 26RFa have been shown to promote food intake and to exert different peripheral actions through G-protein-coupled receptor 103 (GPR103) binding. Moreover, 26RFa was found to inhibit pancreatic insulin secretion, whereas the role of 43RFa on β-cell function is unknown, as well as the effects of both peptides on β-cell survival. Herein, we investigated the effects of 43RFa and 26RFa on survival and apoptosis of pancreatic β-cells and human pancreatic islets. In addition, we explored the role of these peptides on insulin secretion and the underlying signaling mechanisms. Our results show that in INS-1E β-cells and human pancreatic islets both 43RFa and 26RFa prevented cell death and apoptosis induced by serum starvation, cytokine synergism, and glucolipotoxicity, through phosphatidylinositol 3-kinase/Akt- and extracellular signal-related kinase 1/2-mediated signaling. Moreover, 43RFa promoted, whereas 26RFa inhibited, glucose- and exendin-4-induced insulin secretion, through Gαs and Gαi/o proteins, respectively. Inhibition of GPR103 expression by small interfering RNA blocked 43RFa insulinotropic effect, but not the insulinostatic action of 26RFa. Finally, 43RFa, but not 26RFa, induced cAMP increase and glucose uptake. In conclusion, because of their survival effects along with the effects on insulin secretion, these findings suggest potential for 43RFa and 26RFa as therapeutic targets in the treatment of diabetes.
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Affiliation(s)
- Riccarda Granata
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Fabio Settanni
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Letizia Trovato
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Davide Gallo
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Iacopo Gesmundo
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Rita Nano
- Diabetes Research Institute, Division of Immunology, Transplantation, and Infectious Diseases, San Raffaele Scientific Institute, Milan, Italy
| | - Maria Pia Gallo
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | | | - Marco Volante
- Department of Oncology, University of Torino, Torino, Italy
| | - Giuseppe Alloatti
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Lorenzo Piemonti
- Diabetes Research Institute, Division of Immunology, Transplantation, and Infectious Diseases, San Raffaele Scientific Institute, Milan, Italy
| | - Jérôme Leprince
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, International Associated Laboratory Samuel de Champlain, Institute for Research and Innovation in Biomedicine, INSERM U-982, University of Rouen, Rouen, France
| | - Mauro Papotti
- Department of Oncology, University of Torino, Torino, Italy
| | - Hubert Vaudry
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, International Associated Laboratory Samuel de Champlain, Institute for Research and Innovation in Biomedicine, INSERM U-982, University of Rouen, Rouen, France
| | - Huy Ong
- Faculty of Pharmacy, University of Montréal, Montréal, Québec, Canada
| | - Ezio Ghigo
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medical Sciences, University of Torino, Torino, Italy
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Prodam F, Filigheddu N. Ghrelin gene products in acute and chronic inflammation. Arch Immunol Ther Exp (Warsz) 2014; 62:369-84. [PMID: 24728531 DOI: 10.1007/s00005-014-0287-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 03/21/2014] [Indexed: 12/27/2022]
Abstract
Ghrelin gene products--the peptides ghrelin, unacylated ghrelin, and obestatin--have several actions on the immune system, opening new perspectives within neuroendocrinology, metabolism and inflammation. The aim of this review is to summarize the available evidence regarding the less known role of these peptides in the machinery of inflammation and autoimmunity, outlining some of their most promising therapeutic applications.
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Affiliation(s)
- Flavia Prodam
- Departmant of Health Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Novara, Italy
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Bando M, Iwakura H, Ariyasu H, Koyama H, Hosoda K, Adachi S, Nakao K, Kangawa K, Akamizu T. Overexpression of intraislet ghrelin enhances β-cell proliferation after streptozotocin-induced β-cell injury in mice. Am J Physiol Endocrinol Metab 2013; 305:E140-8. [PMID: 23651849 DOI: 10.1152/ajpendo.00112.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Previously, we reported that exogenous administration of ghrelin ameliorates glucose metabolism in a neonate streptozotocin (STZ)-induced diabetic rat model through enhancement of β-cell proliferation. However, it was not clear whether the observed β-cell proliferation was a direct or indirect effect (e.g., via orexigenic or growth hormone-stimulated pathways) of ghrelin activity. Here, we aimed to investigate whether ghrelin directly impacts β-cell proliferation after STZ-induced injury in mice. Seven-week-old male rat insulin II promoter-ghrelin internal ribosomal sequence ghrelin O-acyltransferase transgenic (RIP-GG Tg) mice, which have elevated pancreatic ghrelin levels, but only minor changes in plasma ghrelin levels when fed a medium-chain triglyceride-rich diet, were treated with STZ. Then, serum insulin, pancreatic insulin mRNA expression, and islet histology were evaluated. We found that the serum insulin levels, but not blood glucose levels, of RIP-GG Tg mice were significantly ameliorated 14 days post-STZ treatment. Pancreatic insulin mRNA expression was significantly elevated in RIP-GG Tg mice, and β-cell numbers in islets were increased. Furthermore, the number of phospho-histone H3⁺ or Ki67⁺ proliferating β-cells was significantly elevated in RIP-GG Tg mice, whereas the apoptotic indexes within the islets, as determined by TUNEL assay, were not changed. These results indicate that ghrelin can directly stimulate β-cell proliferation in vivo after β-cell injury even without its orexigenic or GH-stimulating activities, although it did not have enough impact to normalize the glucose tolerance in adult mice.
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Affiliation(s)
- Mika Bando
- Ghrelin Research Project, Translational Research Center, Kyoto University Hospital, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Yang SC, Tseng HL, Shieh KR. Circadian-clock system in mouse liver affected by insulin resistance. Chronobiol Int 2013; 30:796-810. [DOI: 10.3109/07420528.2013.766204] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Aragno M, Mastrocola R, Ghé C, Arnoletti E, Bassino E, Alloatti G, Muccioli G. Obestatin induced recovery of myocardial dysfunction in type 1 diabetic rats: underlying mechanisms. Cardiovasc Diabetol 2012; 11:129. [PMID: 23066908 PMCID: PMC3537569 DOI: 10.1186/1475-2840-11-129] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 09/21/2012] [Indexed: 01/17/2023] Open
Abstract
Background The aim of this study was to investigate whether obestatin (OB), a peptide mediator encoded by the ghrelin gene exerting a protective effect in ischemic reperfused heart, is able to reduce cardiac dysfunctions in adult diabetic rats. Methods Diabetes was induced by STZ injection (50 mg/kg) in Wistar rats (DM). OB was administered (25 μg/kg) twice a day for 6 weeks. Non-diabetic (ND) rats and DM rats were distributed into four groups: untreated ND, OB-treated ND, untreated DM, OB-treated DM. Cardiac contractility and ß-adrenergic response were studied on isolated papillary muscles. Phosphorylation of AMPK, Akt, ERK1/2 and GSK3ß as well ß-1 adrenoreceptors levels were detected by western blot, while α-MHC was measured by RT-PCR. Results OB preserved papillary muscle contractility (85 vs 27% of ND), ß-adrenergic response (103 vs 65% of ND), as well ß1-adrenoreceptors and α-MHC levels in diabetic myocardial tissue. Moreover, OB up-regulated the survival kinases Akt and ERK1/2, and enhanced AMPK and GSK3ß phosphorylation. OB corrected oxidative unbalance, reduced pro-inflammatory cytokine TNF-α plasma levels, NFkB translocation and pro-fibrogenic factors expression in diabetic myocardium. Conclusions OB displays a significant beneficial effect against the alterations of contractility and ß-adrenergic response in the heart of STZ-treated diabetic rats, which was mainly associated with the ability of OB to up-regulate the transcription of ß1-adrenergic receptors and α-MHC; this protective effect was accompanied by the ability to restore oxidative balance and to promote phosphorylation/modulation of AMPK and pro-survival kinases such as Akt, ERK1/2 and GSK3ß.
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Affiliation(s)
- Manuela Aragno
- Department of Experimental Medicine and Oncology, University of Turin, Corso Raffaello 30, Turin, 10125, Italy.
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Pekary AE, Sattin A. Rapid modulation of TRH and TRH-like peptide release in rat brain and peripheral tissues by ghrelin and 3-TRP-ghrelin. Peptides 2012; 36:157-67. [PMID: 22634385 DOI: 10.1016/j.peptides.2012.04.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 04/26/2012] [Accepted: 04/26/2012] [Indexed: 02/04/2023]
Abstract
Ghrelin is not only a modulator of feeding and energy expenditure but also regulates reproductive functions, CNS development and mood. Obesity and major depression are growing public health concerns which may derive, in part, from dysregulation of ghrelin feedback at brain regions regulating feeding and mood. We and others have previously reported that thyrotropin-releasing hormone (TRH, pGlu-His-Pro-NH(2)) and TRH-like peptides (pGlu-X-Pro-NH(2), where "X" can be any amino acid residue) have neuroprotective, antidepressant, anti-epileptic, analeptic, anti-ataxic, and anorectic properties. For this reason male Sprague-Dawley rats were injected ip with 0.1mg/kg rat ghrelin or 0.9mg/kg 3-Trp-rat ghrelin. Twelve brain regions: cerebellum, medulla oblongata, anterior cingulate, posterior cingulate, frontal cortex, nucleus accumbens, hypothalamus, entorhinal cortex, hippocampus, striatum, amygdala, piriform cortex and 5 peripheral tissues (adrenals, testes, epididymis, pancreas and prostate) were analyzed. Rapid and profound decreases in TRH and TRH-like peptide levels (increased release) occurred throughout brain and peripheral tissues following ip ghrelin. Because ghrelin is rapidly deacylated in vivo we also studied 3-Trp-ghrelin which cannot be deacylated. Significant increases in TRH and TRH-like peptide levels following 3-Trp-ghrelin, relative to those after ghrelin were observed in all brain regions except posterior cingulate and all peripheral tissues except prostate and testis. The rapid stimulation of TRH and TRH-like peptide release by ghrelin in contrast with the inhibition of such release by 3-Trp-TRH is consistent with TRH and TRH-like peptides modulating the downstream effects of both ghrelin and unacylated ghrelin.
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Verhulst PJ, Depoortere I. Ghrelin's second life: From appetite stimulator to glucose regulator. World J Gastroenterol 2012; 18:3183-95. [PMID: 22783041 PMCID: PMC3391754 DOI: 10.3748/wjg.v18.i25.3183] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 12/01/2011] [Accepted: 01/18/2012] [Indexed: 02/06/2023] Open
Abstract
Ghrelin, a 28 amino acid peptide hormone produced by the stomach, was the first orexigenic hormone to be discovered from the periphery. The octanoyl modification at Ser3, mediated by ghrelin O-acyltransferase (GOAT), is essential for ghrelin’s biological activity. Ghrelin stimulates food intake through binding to its receptor (GRLN-R) on neurons in the arcuate nucleus of the hypothalamus. Ghrelin is widely expressed throughout the body; accordingly, it is implicated in several other physiological functions, which include growth hormone release, gastric emptying, and body weight regulation. Ghrelin and GRLN-R expression are also found in the pancreas, suggesting a local physiological role. Accordingly, several recent studies now point towards an important role for ghrelin and its receptor in the regulation of blood glucose homeostasis, which is the main focus of this review. Several mechanisms of this regulation by ghrelin have been proposed, and one possibility is through the regulation of insulin secretion. Despite some controversy, most studies suggest that ghrelin exerts an inhibitory effect on insulin secretion, resulting in increased circulating glucose levels. Ghrelin may thus be a diabetogenic factor. Obesity-related type 2 diabetes has become an increasingly important health problem, almost reaching epidemic proportions in the world; therefore, antagonists of the ghrelin-GOAT signaling pathway, which will tackle both energy- and glucose homeostasis, may be considered as promising new therapies for this disease.
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Obestatin and insulin in pancreas of newborn diabetic rats treated with exogenous ghrelin. Acta Histochem 2012; 114:349-57. [PMID: 21803403 DOI: 10.1016/j.acthis.2011.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 07/06/2011] [Accepted: 07/07/2011] [Indexed: 01/24/2023]
Abstract
The aim of the study was to evaluate the effect of ghrelin treatment on obestatin, insulin gene expression and biochemical parameters in the pancreas of newborn-streptozocin (STZ) diabetic rats. Rats were divided into 4 groups. Group I: control rats treated with physiological saline; group II: control rats treated with 100 μg/kg/day ghrelin; group III: two days after birth rats that received 100mg/kg STZ injected as a single dose to induce neonatal diabetes; group IV: neonatal-STZ-diabetic rats treated with ghrelin for four weeks. Sections of the pancreas were examined with immunohistochemistry for the expression of obestatin and insulin and in situ hybridization for the expression of insulin mRNA. The blood glucose levels were measured. Tissue homogenates were used for protein, glutathione, lipid peroxidation and non-enzymatic glycosylation levels and antioxidant enzyme analysis. There was a significant difference in blood glucose levels in newborn-STZ-diabetic rats compared to ghrelin treated diabetic rats at weeks 1, 2 and 4. In group IV, pancreatic non-enzymatic glycosylation and lipid peroxidation levels were decreased, however, glutathione levels and enzymatic activities were increased. Insulin peptide and mRNA (+) signals in islets of Langerhans and obestatin immunopositive cell numbers showed an increase in group IV compared to group III. These results suggest that administration of ghrelin to newborn rats may prevent effects of diabetes.
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Granata R, Gallo D, Luque RM, Baragli A, Scarlatti F, Grande C, Gesmundo I, Córdoba-Chacón J, Bergandi L, Settanni F, Togliatto G, Volante M, Garetto S, Annunziata M, Chanclón B, Gargantini E, Rocchietto S, Matera L, Datta G, Morino M, Brizzi MF, Ong H, Camussi G, Castaño JP, Papotti M, Ghigo E. Obestatin regulates adipocyte function and protects against diet-induced insulin resistance and inflammation. FASEB J 2012; 26:3393-411. [PMID: 22601779 DOI: 10.1096/fj.11-201343] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The metabolic actions of the ghrelin gene-derived peptide obestatin are still unclear. We investigated obestatin effects in vitro, on adipocyte function, and in vivo, on insulin resistance and inflammation in mice fed a high-fat diet (HFD). Obestatin effects on apoptosis, differentiation, lipolysis, and glucose uptake were determined in vitro in mouse 3T3-L1 and in human subcutaneous (hSC) and omental (hOM) adipocytes. In vivo, the influence of obestatin on glucose metabolism was assessed in mice fed an HFD for 8 wk. 3T3-L1, hSC, and hOM preadipocytes and adipocytes secreted obestatin and showed specific binding for the hormone. Obestatin prevented apoptosis in 3T3-L1 preadipocytes by increasing phosphoinositide 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK)1/2 signaling. In both mice and human adipocytes, obestatin inhibited isoproterenol-induced lipolysis, promoted AMP-activated protein kinase phosphorylation, induced adiponectin, and reduced leptin secretion. Obestatin also enhanced glucose uptake in either the absence or presence of insulin, promoted GLUT4 translocation, and increased Akt phosphorylation and sirtuin 1 (SIRT1) protein expression. Inhibition of SIRT1 by small interfering RNA reduced obestatin-induced glucose uptake. In HFD-fed mice, obestatin reduced insulin resistance, increased insulin secretion from pancreatic islets, and reduced adipocyte apoptosis and inflammation in metabolic tissues. These results provide evidence of a novel role for obestatin in adipocyte function and glucose metabolism and suggest potential therapeutic perspectives in insulin resistance and metabolic dysfunctions.
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Affiliation(s)
- Riccarda Granata
- Laboratory of Molecular and Cellular Endocrinology, Department of Internal Medicine, University of Turin, Corso Dogliotti 14-10126 Turin, Italy.
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Abstract
Chronic use of alcohol is considered to be a potential risk factor for the incidence of type 2 diabetes mellitus (T2DM), which causes insulin resistance and pancreatic β-cell dysfunction that is a prerequisite for the development of diabetes. However, alcohol consumption in diabetes has been controversial and more detailed information on the diabetogenic impact of alcohol seems warranted. Diabetes, especially T2DM, causes dysregulation of various metabolic processes, which includes a defect in the insulin-mediated glucose function of adipocytes, and an impaired insulin action in the liver. In addition, neurobiological profiles of alcoholism are linked to the effects of a disruption of glucose homeostasis and of insulin resistance, which are affected by altered appetite that regulates the peptides and neurotrophic factors. Since conditions, which precede the onset of diabetes that are associated with alcoholism is one of the crucial public problems, researches in efforts to prevent and treat diabetes with alcohol dependence, receives special clinical interest. Therefore, the purpose of this mini-review is to provide the recent progress and current theories in the interplay between alcoholism and diabetes. Further, the purpose of this study also includes summarizing the pathophysiological mechanisms in the neurobiology of alcoholism.
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Affiliation(s)
- Soo-Jeong Kim
- Department of Psychiatry, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - Dai-Jin Kim
- Department of Psychiatry, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea
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Granata R, Settanni F, Julien M, Nano R, Togliatto G, Trombetta A, Gallo D, Piemonti L, Brizzi MF, Abribat T, van Der Lely AJ, Ghigo E. Des-acyl ghrelin fragments and analogues promote survival of pancreatic β-cells and human pancreatic islets and prevent diabetes in streptozotocin-treated rats. J Med Chem 2012; 55:2585-96. [PMID: 22352743 DOI: 10.1021/jm201223m] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Des-acyl ghrelin, although devoid of binding to ghrelin receptor (GRLN), exerts many biological effects, including regulation of glucose and lipid metabolism. Indeed, des-acyl ghrelin promotes pancreatic β-cell and human islet cell survival and prevents diabetes in streptozotocin (STZ) treated rats. We investigated whether des-acyl ghrelin fragments excluding serine(3), which is essential for binding to GRLN, would display similar actions. Among the different compounds tested, des-acyl ghrelin((6-13)) and des-acyl ghrelin((6-13)) with alanine substitutions or cyclization, but not with d-amino acid substitutions, showed the best survival effect, similar to des-acyl ghrelin. Des-acyl ghrelin((6-13)) even prevented diabetes in STZ-treated rats and protected human circulating angiogenic cells from oxidative stress and senescence, similar to des-acyl ghrelin. These results suggest that not only full-length des-acyl ghrelin but also short des-acyl ghrelin fragments have clear beneficial effects on several tissues in vitro and in vivo.
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Affiliation(s)
- Riccarda Granata
- Laboratory of Molecular and Cellular Endocrinology, University of Turin, Corso Dogliotti 14, 10126 Turin, Italy.
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Tarabra E, Pelengaris S, Khan M. A simple matter of life and death-the trials of postnatal Beta-cell mass regulation. Int J Endocrinol 2012; 2012:516718. [PMID: 22577380 PMCID: PMC3346985 DOI: 10.1155/2012/516718] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 12/31/2011] [Indexed: 12/17/2022] Open
Abstract
Pancreatic beta-cells, which secrete the hormone insulin, are the key arbiters of glucose homeostasis. Defective beta-cell numbers and/or function underlie essentially all major forms of diabetes and must be restored if diabetes is to be cured. Thus, the identification of the molecular regulators of beta-cell mass and a better understanding of the processes of beta-cell differentiation and proliferation may provide further insight for the development of new therapeutic targets for diabetes. This review will focus on the principal hormones and nutrients, as well as downstream signalling pathways regulating beta-cell mass in the adult. Furthermore, we will also address more recently appreciated regulators of beta-cell mass, such as microRNAs.
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Affiliation(s)
- Elena Tarabra
- School of Life Sciences, Warwick University, Gibbet Hill Road, Coventry CV4 7AL, UK
- *Elena Tarabra:
| | - Stella Pelengaris
- School of Life Sciences, Warwick University, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Michael Khan
- School of Life Sciences, Warwick University, Gibbet Hill Road, Coventry CV4 7AL, UK
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Beléen C, Martínez-Fuentes AJ, Gracia-Navarro F. Role of SST, CORT and ghrelin and its receptors at the endocrine pancreas. Front Endocrinol (Lausanne) 2012; 3:114. [PMID: 23162532 PMCID: PMC3444847 DOI: 10.3389/fendo.2012.00114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 09/03/2012] [Indexed: 12/21/2022] Open
Abstract
Somatostatin (SST), cortistatin (CORT), and its receptors (sst1-5), and ghrelin and its receptors (GHS-R) are two highly interrelated neuropeptide systems with a broad range of overlapping biological actions at central, cardiovascular, and immune levels among others. Besides their potent regulatory role on GH release, its endocrine actions are highlighted by SST/CORT and ghrelin influence on insulin secretion, glucose homeostasis, and insulin resistance. Interestingly, most components of these systems are expressed at the endocrine pancreas and are actively involved in the modulation of pancreatic islet function and, consequently influence glucose homeostasis. In addition, some of them also participate in islet survival and regeneration. Furthermore, under severe metabolic condition as well as in endocrine pathologies, their expression profile is severely deregulated. These findings suggest that SST/CORT and ghrelin systems could play a relevant role in pancreatic function under metabolic and endocrine pathologies. Accordingly, these systems have been therapeutically targeted for the prevention or amelioration of certain metabolic conditions (obesity) as well as for tumor growth inhibition and/or hormonal regulation in endocrine pathologies (neuroendocrine tumors). This review focuses on the interrelationship between SST/CORT and ghrelin systems and their role in severe metabolic conditions and some endocrine disorders.
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Affiliation(s)
- Chanclón Beléen
- Department of Cell Biology, Physiology and Immunology, University of CórdobaCórdoba, Spain
- Instituto Maimónides de Investigación Biomédica de CórdobaCórdoba, Spain
- Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y NutriciónCórdoba, Spain
| | - Antonio J. Martínez-Fuentes
- Department of Cell Biology, Physiology and Immunology, University of CórdobaCórdoba, Spain
- Instituto Maimónides de Investigación Biomédica de CórdobaCórdoba, Spain
- Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y NutriciónCórdoba, Spain
| | - Francisco Gracia-Navarro
- Department of Cell Biology, Physiology and Immunology, University of CórdobaCórdoba, Spain
- Instituto Maimónides de Investigación Biomédica de CórdobaCórdoba, Spain
- Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y NutriciónCórdoba, Spain
- *Correspondence: Francisco Gracia-Navarro, Department of Cell Biology, Physiology and Immunology, University of Córdoba, Campus de Rabanales, Edificio Severo-Ochoa, Planta 3, E-14014 Córdoba, Spain. e-mail:
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Wang X, Ni S, Xu Y, Liang L, Du L, Gu W. Effects of long-term high-fat/high-energy and high-protein diets on insulin and ghrelin expression in developing rats. Endocr Res 2012; 37:97-109. [PMID: 22571486 DOI: 10.3109/07435800.2011.635621] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE This study investigated the long-term effects of high-fat/high-energy and high-protein diets on insulin secretion and ghrelin expression. METHODS Dams of Sprague-Dawley rats were fed a standard, high-fat/high-energy, or high-protein diet during pregnancy and lactation, and their pups were defined as control, high-fat and high-energy, and high-protein groups, respectively. The pups were fed the same diet as their dams after weaning. Plasma glucose, ghrelin, and insulin were analyzed on the first, third, seventh, and tenth postnatal days and at the end of second, third, fourth, eighth, and twelfth weeks. Ghrelin and insulin expression in the pancreas was measured using radioimmunoassay, double-staining immunohistochemistry, and confocal microscopy. RESULTS Fasting blood glucose, plasma insulin concentrations, and homeostasis model assessment-insulin resistance index increased with age. Total plasma ghrelin concentrations decreased with age. Plasma ghrelin concentrations were negatively correlated with glucose levels in all three groups. Plasma ghrelin was negatively correlated with plasma insulin only in the high-fat and high-energy group. Insulin secretion in the high-protein and high-fat and high-energy groups and pancreatic ghrelin content, pancreatic ghrelin-positive cells, and beta cells in all groups decreased with age. The percentage of ghrelin-positive cells correlated with the percentage of beta cells in all groups. CONCLUSION Insulin and ghrelin expression in the plasma and pancreas was adversely affected by long-term high-fat/high-energy and high-protein diets.
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Affiliation(s)
- Xiumin Wang
- Department of Endocrinology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, PR China.
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Baragli A, Lanfranco F, Allasia S, Granata R, Ghigo E. Neuroendocrine and metabolic activities of ghrelin gene products. Peptides 2011; 32:2323-32. [PMID: 22056513 DOI: 10.1016/j.peptides.2011.10.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 10/03/2011] [Accepted: 10/25/2011] [Indexed: 12/15/2022]
Abstract
Acylated ghrelin (AG) is a 28 amino acid gastric peptide a natural ligand for the growth hormone secretagogue (GHS) receptor type 1a (GHS-R1a), endowed with GH-secreting and orexigenic properties. Besides, ghrelin exerts several peripheral metabolic actions, including modulation of glucose homeostasis and stimulation of adipogenesis. Notably, AG administration causes hyperglycemia in rodents as in humans. Ghrelin pleiotropy is supported by a widespread expression of the ghrelin gene, of GHS-R1a and other unknown ghrelin binding sites. The existence of alternative receptors for AG, of several natural ligands for GHS-R1a and of acylation-independent ghrelin non-neuroendocrine activities, suggests that there might be a complex 'ghrelin system' not yet completely explored. Moreover, the patho-physiological implications of unacylated ghrelin (UAG), and obestatin (Ob), the other two ghrelin gene-derived peptides, need to be clarified. Within the next few years, we may better understand the 'ghrelin system', where we might envisage clinical applications.
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Affiliation(s)
- Alessandra Baragli
- Laboratory of Molecular and Cellular Endocrinology, Division of Endocrinology, Department of Internal Medicine, University of Turin, Turin, Italy.
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Kang K, Schmahl J, Lee JM, Garcia K, Patil K, Chen A, Keene M, Murphy A, Sleeman MW. Mouse ghrelin-O-acyltransferase (GOAT) plays a critical role in bile acid reabsorption. FASEB J 2011; 26:259-71. [PMID: 21965605 DOI: 10.1096/fj.11-191460] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Ghrelin is a unique peptide gut hormone that requires post-translational modification to stimulate both feeding and growth hormone release. Ghrelin O-acyltransferase (GOAT) was identified as a specific acyl-transferase for ghrelin, and recent genetic deletion studies of the Goat gene (Goat(-/-)) uncovered the role of ghrelin in the regulation of glucose homeostasis. To further understand the physiological functions of the GOAT/ghrelin system, we have conducted a metabolomic and microarray profile of Goat-null mice, as well as determined Goat expression in different tissues using the lacZ reporter gene. Serum metabolite profile analysis revealed that Goat(-/-) mice exhibited increased secondary bile acids >2.5-fold. This was attributed to increased mRNA and protein expression of the ileal sodium-dependent bile acid transporter (ISBT) in the intestinal and biliary tract. Increased expression of additional solute carrier proteins, including Slc5a12 (>10-fold) were also detected in the small intestine and bile duct. Goat staining was consistently observed in the pituitary glands, stomach, and intestines, and to a lesser extent in the gallbladder and pancreatic duct. This is the first report that the GOAT/ghrelin system regulates bile acid metabolism, and these findings suggest a novel function of GOAT in the regulation of intestinal bile acid reabsorption..
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Affiliation(s)
- Kihwa Kang
- Regeneron Pharmaceuticals, Tarrytown, NY, USA.
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Han SJ, Choi SE, Kang Y, Jung JG, Yi SA, Kim HJ, Lee KW, Kim DJ. Effect of sitagliptin plus metformin on β-cell function, islet integrity and islet gene expression in Zucker diabetic fatty rats. Diabetes Res Clin Pract 2011; 92:213-22. [PMID: 21345512 DOI: 10.1016/j.diabres.2011.01.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 01/12/2011] [Accepted: 01/17/2011] [Indexed: 01/21/2023]
Abstract
AIM The combination of metformin and a dipeptidyl peptidase 4 (DPP-4) inhibitor has been shown to be an effective, safe, and well-tolerated treatment for type 2 diabetes. We evaluated β-cell function and morphological changes in islets in Zucker diabetic fatty (ZDF) rats following combined therapy with sitagliptin and metformin and investigated the expression of potentially relevant genes using cDNA microarrays. METHODS Nine-week-old ZDF rats were randomly divided into four treatment groups: no treatment (control); sitagliptin; metformin, and sitagliptin plus metformin. After 5 weeks of treatment, an oral glucose tolerance test was performed and plasma levels of active GLP-1 and islet morphology and gene expression were assessed. RESULTS Combination therapy reduced fasting glucose and postprandial plasma glucose levels and increased active GLP-1 levels, compared with monotherapy. Combination therapy also increased insulin secretion, the proportion of small islets, and the intensity of insulin staining. Furthermore, it increased the expression of genes involved in cell survival and growth and downregulated apoptosis-associated genes, relative to monotherapy. CONCLUSIONS Combination treatment with sitagliptin and metformin preserved β-cell function and β-cell integrity in ZDF rats. This may be associated with the transcriptional activation of anti-apoptotic and pro-survival genes, as well as the suppression of pro-apoptotic genes.
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Affiliation(s)
- Seung Jin Han
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, San 5, Wonchon-dong, Yeongtong-gu, Suwon, Gyeonggi-do, Republic of Korea
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Granado M, García-Cáceres C, Tuda M, Frago LM, Chowen JA, Argente J. Insulin and growth hormone-releasing peptide-6 (GHRP-6) have differential beneficial effects on cell turnover in the pituitary, hypothalamus and cerebellum of streptozotocin (STZ)-induced diabetic rats. Mol Cell Endocrinol 2011; 337:101-13. [PMID: 21352888 DOI: 10.1016/j.mce.2011.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 01/09/2011] [Accepted: 02/04/2011] [Indexed: 01/21/2023]
Abstract
Poorly controlled type1 diabetes is associated with hormonal imbalances and increased cell death in different tissues, including the pituitary, hypothalamus and cerebellum. In the pituitary, lactotrophs are the cell population with the greatest increase in cell death, whereas in the hypothalamus and cerebellum astrocytes are most highly affected. Insulin treatment can delay, but does not prevent, diabetic complications. As ghrelin and growth hormone (GH) secretagogues are reported to prevent apoptosis in different tissues, and to modulate glucose homeostasis, a combined hormonal treatment may be beneficial. Hence, we analyzed the effect of insulin and GH-releasing peptide 6 (GHRP-6) on diabetes-induced apoptosis in the pituitary, hypothalamus and cerebellum of diabetic rats. Adult male Wistar rats were made diabetic by streptozotocin injection (65 mg/kg ip) and divided into four groups from diabetes onset: those receiving a daily sc injection of saline (1 ml/kg/day), GHRP-6 (150 μg/kg/day), insulin (1-8U/day) or insulin plus GHRP-6 for 8 weeks. Control non-diabetic rats received saline (1 ml/kg/day). Diabetes increased cell death in the pituitary, hypothalamus and cerebellum (P<0.05). In the pituitary, insulin treatment prevented diabetes-induced apoptosis (P<0.01), as well as the decline in prolactin and GH mRNA levels (P<0.05). In the hypothalamus, neither insulin nor GHRP-6 decreased diabetes-induced cell death. However, the combined treatment of insulin+GHRP-6 prevented the diabetes induced-decrease in glial fibrillary acidic protein (GFAP) levels (P<0.05). In the cerebellum, although insulin treatment increased GFAP levels (P<0.01), only the combined treatment of insulin+ GHRP-6 decreased diabetes-induced apoptosis (P<0.05). In conclusion, insulin and GHRP-6 exert tissue specific effects in STZ-diabetic rats and act synergistically on some processes. Indeed, insulin treatment does not seem to be effective on preventing some of the diabetes-induced alterations in the central nervous system.
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Affiliation(s)
- Miriam Granado
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Madrid, Spain
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41
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Ju A, Cheon YH, Lee KS, Lee SS, Lee WY, Won WY, Park SI, Kim WH, Kim DJ. The Change of Plasma Ghrelin and Leptin Levels by the Development of Type 2 Diabetes Mellitus in Patients With Alcohol Dependence. Alcohol Clin Exp Res 2011; 35:905-11. [DOI: 10.1111/j.1530-0277.2010.01420.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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42
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Desgraz R, Bonal C, Herrera PL. β-cell regeneration: the pancreatic intrinsic faculty. Trends Endocrinol Metab 2011; 22:34-43. [PMID: 21067943 DOI: 10.1016/j.tem.2010.09.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 09/27/2010] [Accepted: 09/27/2010] [Indexed: 01/08/2023]
Abstract
Type I diabetes (T1D) patients rely on cumbersome chronic injections of insulin, making the development of alternate durable treatments a priority. The ability of the pancreas to generate new β-cells has been described in experimental diabetes models and, importantly, in infants with T1D. Here we discuss recent advances in identifying the origin of new β-cells after pancreatic injury, with and without inflammation, revealing a surprising degree of cell plasticity in the mature pancreas. In particular, the inducible selective near-total destruction of β-cells in healthy adult mice uncovers the intrinsic capacity of differentiated pancreatic cells to spontaneously reprogram to produce insulin. This opens new therapeutic possibilities because it implies that β-cells can differentiate endogenously, in depleted adults, from heterologous origins.
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Affiliation(s)
- Renaud Desgraz
- Department of Cell Physiology and Metabolism, University of Geneva Faculty of Medicine, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland
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43
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Yang GK, Yip L, Fredholm BB, Kieffer TJ, Kwok YN. Involvement of adenosine signaling in controlling the release of ghrelin from the mouse stomach. J Pharmacol Exp Ther 2010; 336:77-86. [PMID: 20876230 DOI: 10.1124/jpet.110.171280] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ghrelin, a potent orexigenic hormone released from the stomach, is important in regulating energy metabolism. Abnormal ghrelin levels are associated with eating disorders and metabolic diseases. However, factors involved in the regulation of ghrelin release remain unclear. Here, we examined the involvement of adenosine signaling in the control of ghrelin release from the perfused mouse stomach. Adenosine stimulated ghrelin release concentration-dependently, and the A(2A) receptor-selective antagonists 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM 241385) and 2-(2-furanyl)-7-(2-phenylethyl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine (SCH 58261) abolished the increased release. The A(2A) receptor-selective agonist 2-p-(2-carboxyethyl)phenethylamino-5-N-ethylcarboxamidoadenosine hydrochloride (CGS 21680) augmented ghrelin release concentration-dependently, whereas the A(1) receptor-selective agonist 2-chloro-N(6)-cyclopentyladenosine inhibited ghrelin release. In A(2A) receptor knockout mice, adenosine inhibited ghrelin release, and the A(1) receptor-selective antagonist 8-cyclopentyl-1,3-dipropylxanthine blocked this inhibition. The adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine hydrochloride increased ghrelin release in wild-type and A(1) receptor knockout mice but not in A(2A) receptor knockout mice. Colocalization of ghrelin immunoreactivity with A(1) and A(2A) receptor immunoreactivities in the gastric nerve fibers were observed. Colocalization was also detected for ghrelin and A(1) receptor immunoreactivities in the gastric mucosa. Blockade of neural activities with tetrodotoxin abolished the stimulatory effect of adenosine on ghrelin release. In conclusion, adenosine exerts predominantly a tonic A(2A) receptor-mediated stimulatory action on gastric ghrelin release, whereas an A(1) receptor-mediated inhibitory action is also apparent when the tonic excitatory effect was removed.
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Affiliation(s)
- Gary K Yang
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z3
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Development of PACAP38 analogue with improved stability: physicochemical and in vitro/in vivo pharmacological characterization. J Mol Neurosci 2010; 43:85-93. [PMID: 20585898 DOI: 10.1007/s12031-010-9415-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Accepted: 06/15/2010] [Indexed: 10/19/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide 38 (PACAP38), one of the major peptide transmitters, has emerged as a promising drug candidate for the treatment of type 2 diabetes. In the present study, on the basis of previous structure-activity relationships, a new PACAP38 derivative, [R(15, 20, 21), L(17)]-PACAP38, was chemically synthesized with the aim of enhancing the therapeutic potential of PACAP38. The solution structure of the new derivative was almost identical to that of PACAP38 as evaluated by circular dichroic spectroscopy, and both PACAP38 and the new derivative stimulated adenylate cyclase in rat insulinoma RIN-m5F cells with EC(50) values of 4.6 and 5.5 nM, respectively. Stability studies revealed the gradual degradation of PACAPs in rat serum, although there appeared to be a 42% reduction in degradation kinetics for [R(15, 20, 21), L(17)]-PACAP38 compared with that of PACAP38. The novel derivative also exhibited more potent protective effects against streptozotocin (STZ)-induced apoptotic death of RIN-m5F cells, possibly due to the enhanced stability. The n0-STZ model, in which neonatal rats were injected with STZ at birth, developed a typical diabetic condition; however, chronic administration of [R(15, 20, 21), L(17)]-PACAP38 resulted in protection of pancreatic islets, followed by the improvement of glycemic control. Thus, the chemical modification of PACAP38 led to the development of a new promising derivative with enhanced stability and biological activity, and early administration of [R(15, 20, 21), L(17)]-PACAP38 might be of help for preventing the development of diabetes in type 2 diabetic model rats.
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Granado M, García-Cáceres C, Frago LM, Argente J, Chowen JA. The positive effects of growth hormone-releasing peptide-6 on weight gain and fat mass accrual depend on the insulin/glucose status. Endocrinology 2010; 151:2008-18. [PMID: 20219977 DOI: 10.1210/en.2009-1394] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Ghrelin and GH secretagogues, including GH-releasing peptide (GHRP)-6, stimulate food intake and adiposity. Because insulin modulates the hypothalamic response to GH secretagogues and acts synergistically with ghrelin on lipogenesis in vitro, we analyzed whether insulin plays a role in the metabolic effects of GHRP-6 in vivo. Streptozotocin-induced diabetic rats received saline, GHRP-6, insulin, or insulin plus GHRP-6 once daily for 8 wk. Rats receiving saline suffered hyperglycemia, hyperphagia, polydipsia, and weight loss. Insulin, but not GHRP-6, improved these parameters (P < 0.001 for all), as well as the diabetes-induced increase in hypothalamic mRNA levels of neuropeptide Y and agouti-related peptide and decrease in proopiomelanocortin. Cocaine amphetamine-related transcript mRNA levels were also reduced in diabetic rats, with GHRP-6 inducing a further decrease (P < 0.03) and insulin an increase. Diabetic rats receiving insulin plus GHRP-6 gained more weight and had increased epididymal fat mass and serum leptin levels compared with all other groups (P < 0.001). In epididymal adipose tissue, diabetic rats injected with saline had smaller adipocytes (P < 0.001), decreased fatty acid synthase (FAS; P < 0.001), and glucose transporter-4 (P < 0.001) and increased hormone sensitive lipase (P < 0.001) and proliferator-activated receptor-gamma mRNA levels (P < 0.01). Insulin normalized these parameters to control values. GHRP-6 treatment increased FAS and glucose transporter-4 gene expression and potentiated insulin's effect on epididymal fat mass, adipocyte size (P < 0.001), FAS (P < 0.001), and glucose transporter-4 (P < 0.05). In conclusion, GHRP-6 and insulin exert an additive effect on weight gain and visceral fat mass accrual in diabetic rats, indicating that some of GHRP-6's metabolic effects depend on the insulin/glucose status.
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Affiliation(s)
- Miriam Granado
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Avenida Menéndez Pelayo, Madrid, Spain
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Chen CY, Fujimiya M, Laviano A, Chang FY, Lin HC, Lee SD. Modulation of ingestive behavior and gastrointestinal motility by ghrelin in diabetic animals and humans. J Chin Med Assoc 2010; 73:225-9. [PMID: 20685586 DOI: 10.1016/s1726-4901(10)70048-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 04/16/2010] [Indexed: 02/07/2023] Open
Abstract
Acyl ghrelin, a 28-amino acid peptide hormone, is the endogenous cognate ligand for the growth hormone secretagogue receptor. Ghrelin is involved in stimulating growth hormone release, eliciting feeding behavior, inducing adiposity and stimulating gastrointestinal motility. Ghrelin is unique for its post-translational modification of O-n-octanoylation at serine 3 through ghrelin O-acyltransferase, and is the only peripheral signal to enhance food intake. Plasma ghrelin levels manifest "biphasic changes" in diabetes mellitus (DM). In the early stage of DM, the stomach significantly increases the secretion of ghrelin into the plasma, and elevated plasma ghrelin levels are correlated with diabetic hyperphagic feeding and accelerated gastrointestinal motility. In the late stage of DM, plasma ghrelin levels may be lower, which might be linked with anorexia/muscle wasting, delayed gastrointestinal transit, and even gastroparesis. Therefore, the unique ghrelin system may be the most important player compared to the other hindgut hormones participating in the "entero-insular axis". Further studies using either knockdown or knockout of ghrelin gene products and ghrelin O-acyltransferase may unravel the pathogenesis of DM, and show benefits in combating this disease and metabolic syndrome.
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Affiliation(s)
- Chih-Yen Chen
- Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, 201, Section 2, Shih-Pai Road, Taipei 112, Taiwan, R.O.C.
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Cruz SA, Tseng YC, Kaiya H, Hwang PP. Ghrelin affects carbohydrate-glycogen metabolism via insulin inhibition and glucagon stimulation in the zebrafish (Danio rerio) brain. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:190-200. [PMID: 20138234 DOI: 10.1016/j.cbpa.2010.01.019] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 01/30/2010] [Accepted: 01/30/2010] [Indexed: 02/09/2023]
Abstract
Carbohydrate-glycogen metabolism (CGM) is critical for emergency energy supplies in the central nervous system (CNS). Ghrelin (GHRL) in pancreas is known to significantly regulate a dominant player in CGM, insulin (INS). However, its regulatory effect on extrapancreatic INS synthesis is yet unknown. In this study, we used adult zebrafish to elucidate the expression and role of zebrafish GHRL (zGHRL) in genes primarily involved in the brain's CGM. Results showed that zebrafish brain expressed zghrl and its receptor, growth hormone secretagogue-receptor (GHS-R: zghs-r1a and zghs-r2a), according to RT-PCR and in situ hybridization. Protein localization coupled with mRNA spatial expression further verified zGHRL's presence in the brain. For the in vivo study, significant increases in zghs-r1a and zghs-r2a synthesis were observed after injection of synthetic peptide goldfish GHRL-12 (gGHRL) using brain templates analyzed by quantitative real-time PCR (qPCR). Ligand-receptor synthesis of INS (zinsa; zins-r1 and zins-r2) significantly decreased, while glucagon (GCG) (zgcgb1 and zgcgb2; zgcg-r1 and zgcg-r2) exhibited a significant transient increase. In CGM, subsequent processes indicate urgent glucose-sensing response that will balance glycogen degradation and energy storage. Taken together, these findings suggest that GHRL regulates INS synthesis by mediating its action on GHS-R in the CNS and partly involved in CGM.
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Affiliation(s)
- Shelly A Cruz
- Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan, ROC
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Yamamoto K, Takiguchi S, Miyata H, Adachi S, Hiura Y, Yamasaki M, Nakajima K, Fujiwara Y, Mori M, Kangawa K, Doki Y. Randomized phase II study of clinical effects of ghrelin after esophagectomy with gastric tube reconstruction. Surgery 2010; 148:31-8. [PMID: 20096432 DOI: 10.1016/j.surg.2009.11.026] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 11/25/2009] [Indexed: 10/19/2022]
Abstract
BACKGROUND Ghrelin is a peptide hormone with pleiotropic functions including stimulation of growth hormone secretion and appetite, and its levels decrease after esophagectomy. The aim of this study was to evaluate whether exogenous ghrelin administration can meliorate the postoperative decrease of oral food intake and body weight, which are serious complications after esophagectomy. METHODS This prospective randomized, placebo-controlled, clinical trial assigned a total of 20 patients with thoracic esophageal cancer who underwent radical operation into either a ghrelin (n =10) or placebo (n =10) group. Synthetic human ghrelin (3 microg/kg) or 0.9% saline placebo was administered intravenously twice daily for 10 days from the day after the start of food intake. The primary end point was calories of food intake. Comparison of appetite and changes in weight and body composition were also made between the 2 groups. RESULTS Intake of food calories was greater in ghrelin group than placebo group (mean 874 vs 605 kcal per day; P =.015). The appetite score tended to be greater in ghrelin group than placebo group (P =.094). Loss of weight was less in ghrelin group (-1% vs -3%; P =.019) and this attenuation was due largely to a decrease of lean body weight loss (0% vs -4%; P =.012). No side effects were observed in either groups. CONCLUSION These preliminary results suggest that administration of ghrelin after esophagectomy increased oral food intake and attenuated weight loss together with maintenance of lean body weight.
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Affiliation(s)
- Kazuyoshi Yamamoto
- Division of Gastroenterological Surgery, Department of Surgery, Graduate School of Medicine, Osaka University, Osaka, Japan
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Kodama M, Tsukamoto K, Yoshida K, Aoki K, Kanegasaki S, Quinn G. Embryonic stem cell transplantation correlates with endogenous neurogenin 3 expression and pancreas regeneration in streptozotocin-injured mice. J Histochem Cytochem 2009; 57:1149-58. [PMID: 19729673 DOI: 10.1369/jhc.2009.954206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pancreatic beta cell regeneration remains poorly understood, yet stimulation of adult beta cell neogenesis could lead to therapies for type 1 and type 2 diabetes. We studied the effect of embryonic stem (ES) cell transplantation on pancreas regeneration following beta cell injury. Female Balb/c nude mice were treated with streptozotocin to induce hyperglycemia and received an ES cell transplant 24 hr later beneath the renal capsule. Transplantation of ES cells prevented hyperglycemia in a subset of mice, maintaining euglycemia and mild glucose tolerance up to 5 weeks. Pancreata of euglycemic mice showed histological evidence of beta cell regeneration and expression of pancreas and duodenum transcription factor-1 (PDX-1) and neurogenin 3 (Ngn3) in ductal epithelium. Cell tracing analysis indicated that significant beta cell neogenesis from progenitor cells occurred between 2 to 3 weeks following injury in ES cell-transplanted mice but not in sham-transplanted animals. Significantly, whereas pancreas-localized ES cells or their derivatives were adjacent to sites of regeneration, neogenic pancreatic epithelia, including Ngn3+ cells, were endogenous. In conclusion, transplanted ES cells can migrate to the injured pancreas. Transplantation is associated with enhanced endogenous regeneration characterized by expression of Ngn3 and increased beta cell differentiation from endogenous progenitor cells.
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Affiliation(s)
- Maho Kodama
- Section for Studies on Metastasis, National Cancer Center Research Institute, Tokyo, Japan
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Exogenous ghrelin enhances endocrine and exocrine regeneration in pancreatectomized rats. J Gastrointest Surg 2009; 13:775-83. [PMID: 19082668 DOI: 10.1007/s11605-008-0778-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Accepted: 11/24/2008] [Indexed: 01/31/2023]
Abstract
AIM Ghrelin, the most important modulator of endocrine and exocrine pancreatic functions, has a role in the development of islets of Langerhans during embryogenesis. The aim of this study was to evaluate the effects of ghrelin on pancreatic regeneration in rats with 90% pancreatectomy. MATERIALS AND METHODS Two- to 3-week-old Wistar rats were used in the study. After anesthesia, 90% pancreatectomy was performed. In the ghrelin group, 90% pancreatectomy was performed. Ten nanomoles per kilogram per day of ghrelin was administered intraperitoneally from the first postoperative day. In the antagonist group, 90% pancreatectomy was performed. From the first postoperative day, rats received the ghrelin receptor antagonists and substance P intraperitoneally at 1 mumol/kg. In the control group, 90% pancreatectomy was performed, and intraperitoneal saline was administered. The sham group did not receive pancreatectomy. Eight rats from each group were randomly selected and sacrificed on the second, third, and 30th days. RESULTS Blood glucose levels in pacreatectomized rats were significantly higher than in rats in the sham group. The number of beta islet cells, serum insulin levels, and PDX-1 and cytokeratin staining scores decreased in rats with pancreatectomy when compared to the sham-group rats. In the ghrelin-receiving rats, blood glucose levels tended to decrease from the 15th postoperative day. Ghrelin treatment increased insulin levels, insulin-positive islet cell number, and 5-bromo-2-deoxyuridine and PDX-1 staining, whereas ghrelin antagonist administration resulted in significant decreases in these parameters. Ghrelin treatment significantly improved glucose tolerance test results. CONCLUSION Exogenous ghrelin administration decreased blood glucose levels after 90% pancreatectomy by increasing islet cell numbers and enhancing endocrine and exocrine regeneration.
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