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Elibol E, Akdevelioğlu Y, Yılmaz C, Narlı B, Şen S, Take Kaplanoğlu G, Seymen CM. Acyl ghrelin, desacyl ghrelin and their ratio affect hepatic steatosis via PPARγ signaling pathway. Arab J Gastroenterol 2024; 25:109-117. [PMID: 38383264 DOI: 10.1016/j.ajg.2023.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 09/11/2023] [Accepted: 12/30/2023] [Indexed: 02/23/2024]
Abstract
BACKGROUND AND STUDY AIMS Ghrelin is an appetite hormone-containing 28-amino acid and has 4 different forms in the body. Ghrelin forms have different physiological functions in the body. This study aims to analyze the effect of acyl and desacyl ghrelin hormone on hepatic steatosis and biochemical findings in 36 male Wistar rats. MATERIALS AND METHODS Rats were split into 6 equal groups, consisting of control, acyl ghrelin, desacyl ghrelin, acyl/desacyl 3:1, acyl/desacyl 1:1, and acyl/desacyl 1:3 groups, and administered placebo or 200 ng/kg hormone subcutaneous twice a day for 14 days. Oral Glucose Tolerance Test (OGTT) was performed on Day 15, Insulin Tolerance Test (ITT) on Day 16, and scarification procedure on Day 17. Certain biochemical data and liver diacylglycerol (DAG), glycogen, protein kinase C and PPAR-γ levels were detected in the blood. Histological analyses were also conducted on the liver tissues. RESULTS The highest plasma total cholesterol and VLDL-K levels were found in the acyl/desacyl 1:3 group, and lower insulin, and HOMA-IR levels were found in groups where acyl and desacyl were administered together (p < 0.05). PPAR-γ gene expression level increased in acyl ghrelin and acyl/desacyl 1:3 groups compared to the control group. Protein kinase C gene expression was highest in the acyl/desacyl 1:3 group. The most severe degenerative findings compliant with steatosis in the liver were observed in the acyl ghrelin group (p < 0.05). CONCLUSION It was determined that administering rats acyl alone and acyl/desacyl by 1:3 caused the highest PPAR-γ gene expression, serum total cholesterol, HDL-K, and VLDL-K levels in the body. Besides, it is shown that desacyl ghrelin effectively regulates the blood glucose level when administered alone.
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Affiliation(s)
- Emine Elibol
- Departments of Nutrition and Dietetic, Ankara Yıldırım Beyazıt University, Dumlupınar Mahallesi, 06760 Çubuk, Ankara, Turkey.
| | - Yasemin Akdevelioğlu
- Departments of Nutrition and Dietetic, Gazi University, Emek mah. Bişkek Cad. 6. Cad. No:2 06490 Çankaya, Ankara, Turkey.
| | - Canan Yılmaz
- Departments of Medical Biochemistry, Gazi University, Faculty of Medicine, 06500 Beşevler, Ankara, Turkey.
| | - Belkıs Narlı
- Departments of Medical Biochemistry, Gazi University, Faculty of Medicine, 06500 Beşevler, Ankara, Turkey.
| | - Serkan Şen
- Departments of Medical Biochemistry, Afyonkarahisar Health Sciences University, Ali Çetinkaya Kampüsü Afyon- İzmir Karayolu 5.km, Afyonkarahisar, Turkey.
| | - Gülnur Take Kaplanoğlu
- Departments of Histology and Embryology, Gazi University Faculty of Medicine, 06500 Beşevler, Ankara, Turkey.
| | - Cemile Merve Seymen
- Departments of Histology and Embryology, Gazi University Faculty of Medicine, 06500 Beşevler, Ankara, Turkey.
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Notaro NM, Dyck DJ. Regulation of peripheral tissue substrate metabolism by the gut-derived hormone ghrelin. Metabol Open 2024; 21:100279. [PMID: 38487670 PMCID: PMC10937159 DOI: 10.1016/j.metop.2024.100279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 03/17/2024] Open
Abstract
Ghrelin increases in the circulation prior to entrained mealtimes, with the acylated (AG) form functioning to stimulate food intake and growth hormone release. Acutely, AG induces whole-body insulin resistance, potentially to maintain glycemia between meals. Alternatively, chronic administration of both AG and the unacylated isoform of ghrelin (unAG) is associated with improved skeletal muscle insulin sensitivity as well as reduced intramuscular lipids and inflammation. This may be due to effects on lipid metabolism, with ghrelin promoting storage of fat in adipose and liver while stimulating oxidation in skeletal muscle, preventing ectopic lipid accumulation. This is of specific relevance in the handling of meal-derived lipids, as ghrelin rises preprandially with effects persisting for 2-3 h following exposure in skeletal muscle, coinciding with elevated plasma FFAs. We hypothesize that ghrelin acts as a preparatory signal for incoming lipids, as well as a regulatory hormone for their use and storage. The effects of ghrelin on skeletal muscle are lost with high fat diet feeding and physical inactivity, potentially being implicated in the pathogenesis of metabolic disease. This review summarizes the metabolic effects of both ghrelin isoforms on peripheral tissues including the pancreas, adipose, liver, and skeletal muscle. Additionally, we speculate on the physiological relevance of these effects in vivo and suggest that ghrelin may be a key regulatory hormone for nutrient handling in the postprandial state.
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Affiliation(s)
- Nicole M. Notaro
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - David J. Dyck
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
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Tuero C, Becerril S, Ezquerro S, Neira G, Frühbeck G, Rodríguez A. Molecular and cellular mechanisms underlying the hepatoprotective role of ghrelin against NAFLD progression. J Physiol Biochem 2023; 79:833-849. [PMID: 36417140 DOI: 10.1007/s13105-022-00933-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 11/12/2022] [Indexed: 11/24/2022]
Abstract
The underlying mechanisms for the development and progression of nonalcoholic fatty liver disease (NAFLD) are complex and multifactorial. Within the last years, experimental and clinical evidences support the role of ghrelin in the development of NAFLD. Ghrelin is a gut hormone that plays a major role in the short-term regulation of appetite and long-term regulation of adiposity. The liver constitutes a target for ghrelin, where this gut-derived peptide triggers intracellular pathways regulating lipid metabolism, inflammation, and fibrosis. Interestingly, circulating ghrelin levels are altered in patients with metabolic diseases, such as obesity, type 2 diabetes, and metabolic syndrome, which, in turn, are well-known risk factors for the pathogenesis of NAFLD. This review summarizes the molecular and cellular mechanisms involved in the hepatoprotective action of ghrelin, including the reduction of hepatocyte lipotoxicity via autophagy and fatty acid β-oxidation, mitochondrial dysfunction, endoplasmic reticulum stress and programmed cell death, the reversibility of the proinflammatory phenotype in Kupffer cells, and the inactivation of hepatic stellate cells. Together, the metabolic and inflammatory pathways regulated by ghrelin in the liver support its potential as a therapeutic target to prevent NAFLD in patients with metabolic disorders.
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Affiliation(s)
- Carlota Tuero
- Department of General Surgery, Clínica Universidad de Navarra, School of Medicine, University of Navarra, Pamplona, Spain
| | - Sara Becerril
- Metabolic Research Laboratory, Clínica Universidad de Navarra, 31008, Pamplona, Irunlarrea 1, Spain
- CIBER Fisiopatología de La Obesidad Y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
- Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Silvia Ezquerro
- Metabolic Research Laboratory, Clínica Universidad de Navarra, 31008, Pamplona, Irunlarrea 1, Spain
| | - Gabriela Neira
- Metabolic Research Laboratory, Clínica Universidad de Navarra, 31008, Pamplona, Irunlarrea 1, Spain
| | - Gema Frühbeck
- Metabolic Research Laboratory, Clínica Universidad de Navarra, 31008, Pamplona, Irunlarrea 1, Spain
- CIBER Fisiopatología de La Obesidad Y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
- Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
- Department of Endocrinology & Nutrition, Clínica Universidad de Navarra, Pamplona, Spain
| | - Amaia Rodríguez
- Metabolic Research Laboratory, Clínica Universidad de Navarra, 31008, Pamplona, Irunlarrea 1, Spain.
- CIBER Fisiopatología de La Obesidad Y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain.
- Obesity and Adipobiology Group, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.
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Townsend LK, Steinberg GR. AMPK and the Endocrine Control of Metabolism. Endocr Rev 2023; 44:910-933. [PMID: 37115289 DOI: 10.1210/endrev/bnad012] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/10/2023] [Accepted: 04/24/2023] [Indexed: 04/29/2023]
Abstract
Complex multicellular organisms require a coordinated response from multiple tissues to maintain whole-body homeostasis in the face of energetic stressors such as fasting, cold, and exercise. It is also essential that energy is stored efficiently with feeding and the chronic nutrient surplus that occurs with obesity. Mammals have adapted several endocrine signals that regulate metabolism in response to changes in nutrient availability and energy demand. These include hormones altered by fasting and refeeding including insulin, glucagon, glucagon-like peptide-1, catecholamines, ghrelin, and fibroblast growth factor 21; adipokines such as leptin and adiponectin; cell stress-induced cytokines like tumor necrosis factor alpha and growth differentiating factor 15, and lastly exerkines such as interleukin-6 and irisin. Over the last 2 decades, it has become apparent that many of these endocrine factors control metabolism by regulating the activity of the AMPK (adenosine monophosphate-activated protein kinase). AMPK is a master regulator of nutrient homeostasis, phosphorylating over 100 distinct substrates that are critical for controlling autophagy, carbohydrate, fatty acid, cholesterol, and protein metabolism. In this review, we discuss how AMPK integrates endocrine signals to maintain energy balance in response to diverse homeostatic challenges. We also present some considerations with respect to experimental design which should enhance reproducibility and the fidelity of the conclusions.
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Affiliation(s)
- Logan K Townsend
- Centre for Metabolism Obesity and Diabetes Research, Hamilton, ON L8S 4L8, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Gregory R Steinberg
- Centre for Metabolism Obesity and Diabetes Research, Hamilton, ON L8S 4L8, Canada
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
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Hoecht EM, Budd JM, Notaro NM, Holloway GP, Dyck DJ. Stimulation of fat oxidation in rat muscle by unacylated ghrelin persists for 2-3 hours, but is independent of fatty acid transporter translocation. Physiol Rep 2023; 11:e15815. [PMID: 37726258 PMCID: PMC10509152 DOI: 10.14814/phy2.15815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/01/2023] [Accepted: 08/11/2023] [Indexed: 09/21/2023] Open
Abstract
While a definitive mechanism-of-action remains to be identified, recent findings indicate that ghrelin, particularly the unacylated form (UnAG), stimulates skeletal muscle fatty acid oxidation. The biological importance of UnAG-mediated increases in fat oxidation remains unclear, as UnAG peaks in the circulation before mealtimes, and decreases rapidly during the postprandial situation before increases in postabsorptive circulating lipids. Therefore, we aimed to determine if the UnAG-mediated stimulation of fat oxidation would persist long enough to affect the oxidation of meal-derived fatty acids, and if UnAG stimulated the translocation of fatty acid transporters to the sarcolemma as a mechanism-of-action. In isolated soleus muscle strips from male rats, short-term pre-treatment with UnAG elicited a persisting stimulus on fatty acid oxidation 2 h after the removal of UnAG. UnAG also caused an immediate phosphorylation of AMPK, but not an increase in plasma membrane FAT/CD36 or FABPpm. There was also no increase in AMPK signaling or increased FAT/CD36 or FABPpm content at the plasma membrane at 2 h which might explain the sustained increase in fatty acid oxidation. These findings confirm UnAG as a stimulator of fatty acid oxidation and provide evidence that UnAG may influence the handling of postprandial lipids. The underlying mechanisms are not known.
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Affiliation(s)
- Evan M. Hoecht
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Joshua M. Budd
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Nicole M. Notaro
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Graham P. Holloway
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - David J. Dyck
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
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Meanti R, Bresciani E, Rizzi L, Coco S, Zambelli V, Dimitroulas A, Molteni L, Omeljaniuk RJ, Locatelli V, Torsello A. Potential Applications for Growth Hormone Secretagogues Treatment of Amyotrophic Lateral Sclerosis. Curr Neuropharmacol 2023; 21:2376-2394. [PMID: 36111771 PMCID: PMC10616926 DOI: 10.2174/1570159x20666220915103613] [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: 06/01/2022] [Revised: 07/18/2022] [Accepted: 08/01/2022] [Indexed: 11/22/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) arises from neuronal death due to complex interactions of genetic, molecular, and environmental factors. Currently, only two drugs, riluzole and edaravone, have been approved to slow the progression of this disease. However, ghrelin and other ligands of the GHS-R1a receptor have demonstrated interesting neuroprotective activities that could be exploited in this pathology. Ghrelin, a 28-amino acid hormone, primarily synthesized and secreted by oxyntic cells in the stomach wall, binds to the pituitary GHS-R1a and stimulates GH secretion; in addition, ghrelin is endowed with multiple extra endocrine bioactivities. Native ghrelin requires esterification with octanoic acid for binding to the GHS-R1a receptor; however, this esterified form is very labile and represents less than 10% of circulating ghrelin. A large number of synthetic compounds, the growth hormone secretagogues (GHS) encompassing short peptides, peptoids, and non-peptidic moieties, are capable of mimicking several biological activities of ghrelin, including stimulation of GH release, appetite, and elevation of blood IGF-I levels. GHS have demonstrated neuroprotective and anticonvulsant effects in experimental models of pathologies both in vitro and in vivo. To illustrate, some GHS, currently under evaluation by regulatory agencies for the treatment of human cachexia, have a good safety profile and are safe for human use. Collectively, evidence suggests that ghrelin and cognate GHS may constitute potential therapies for ALS.
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Affiliation(s)
- Ramona Meanti
- School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, Monza, 20900, Italy
| | - Elena Bresciani
- School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, Monza, 20900, Italy
| | - Laura Rizzi
- School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, Monza, 20900, Italy
| | - Silvia Coco
- School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, Monza, 20900, Italy
| | - Vanessa Zambelli
- School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, Monza, 20900, Italy
| | - Anna Dimitroulas
- Faculty of Health and Medical Sciences, University of Surrey, Stag Hill, Guildford, GU2 7XH, United Kingdom
| | - Laura Molteni
- School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, Monza, 20900, Italy
| | - Robert J. Omeljaniuk
- Department of Biology, Lakehead University, 955 Oliver Rd, Thunder Bay, Ontario, P7B 5E1, Canada
| | - Vittorio Locatelli
- School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, Monza, 20900, Italy
| | - Antonio Torsello
- School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, Monza, 20900, Italy
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Kharbanda KK, Farokhnia M, Deschaine SL, Bhargava R, Rodriguez-Flores M, Casey CA, Goldstone AP, Jerlhag E, Leggio L, Rasineni K. Role of the ghrelin system in alcohol use disorder and alcohol-associated liver disease: A narrative review. Alcohol Clin Exp Res 2022; 46:2149-2159. [PMID: 36316764 PMCID: PMC9772086 DOI: 10.1111/acer.14967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/21/2022] [Accepted: 10/28/2022] [Indexed: 11/07/2022]
Abstract
Unhealthy alcohol consumption is a global health problem. Adverse individual, public health, and socioeconomic consequences are attributable to harmful alcohol use. Epidemiological studies have shown that alcohol use disorder (AUD) and alcohol-associated liver disease (ALD) are the top two pathologies among alcohol-related diseases. Consistent with the major role that the liver plays in alcohol metabolism, uncontrolled drinking may cause significant damage to the liver. This damage is initiated by excessive fat accumulation in the liver, which can further progress to advanced liver disease. The only effective therapeutic strategies currently available for ALD are alcohol abstinence or liver transplantation. Any molecule with dual-pronged effects at the central and peripheral organs controlling addictive behaviors and associated metabolic pathways are a potentially important therapeutic target for treating AUD and ALD. Ghrelin, a hormone primarily derived from the stomach, has such properties, and regulates both behavioral and metabolic functions. In this review, we highlight recent advances in understanding the peripheral and central functions of the ghrelin system and its role in AUD and ALD pathogenesis. We first discuss the correlation between blood ghrelin concentrations and alcohol use or abstinence. Next, we discuss the role of ghrelin in alcohol-seeking behaviors and finally its role in the development of fatty liver by metabolic regulations and organ crosstalk. We propose that a better understanding of the ghrelin system could open an innovative avenue for improved treatments for AUD and associated medical consequences, including ALD.
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Affiliation(s)
- Kusum K. Kharbanda
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Mehdi Farokhnia
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse, Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism, Division of Intramural Clinical and Biological Research, National Institutes of Health, Baltimore and Bethesda, Maryland, USA
- Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Sara L. Deschaine
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse, Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism, Division of Intramural Clinical and Biological Research, National Institutes of Health, Baltimore and Bethesda, Maryland, USA
| | - Raghav Bhargava
- PsychoNeuroEndocrinology Research Group, Division of Psychiatry, Department of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK
| | - Marcela Rodriguez-Flores
- PsychoNeuroEndocrinology Research Group, Division of Psychiatry, Department of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK
| | - Carol A. Casey
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Anthony P. Goldstone
- PsychoNeuroEndocrinology Research Group, Division of Psychiatry, Department of Brain Sciences, Imperial College London, Hammersmith Hospital, London, UK
| | - Elisabet Jerlhag
- Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Lorenzo Leggio
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse, Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism, Division of Intramural Clinical and Biological Research, National Institutes of Health, Baltimore and Bethesda, Maryland, USA
- Medication Development Program, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland, USA
- Center for Alcohol and Addiction Studies, Department of Behavioral and Social Sciences, Brown University, Providence, Rhode Island, USA
- Division of Addiction Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
- Department of Neuroscience, Georgetown University Medical Center, Washington DC, USA
| | - Karuna Rasineni
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Osna NA, Rasineni K, Ganesan M, Donohue TM, Kharbanda KK. Pathogenesis of Alcohol-Associated Liver Disease. J Clin Exp Hepatol 2022; 12:1492-1513. [PMID: 36340300 PMCID: PMC9630031 DOI: 10.1016/j.jceh.2022.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/25/2022] [Indexed: 12/12/2022] Open
Abstract
Excessive alcohol consumption is a global healthcare problem with enormous social, economic, and clinical consequences. While chronic, heavy alcohol consumption causes structural damage and/or disrupts normal organ function in virtually every tissue of the body, the liver sustains the greatest damage. This is primarily because the liver is the first to see alcohol absorbed from the gastrointestinal tract via the portal circulation and second, because the liver is the principal site of ethanol metabolism. Alcohol-induced damage remains one of the most prevalent disorders of the liver and a leading cause of death or transplantation from liver disease. Despite extensive research on the pathophysiology of this disease, there are still no targeted therapies available. Given the multifactorial mechanisms for alcohol-associated liver disease pathogenesis, it is conceivable that a multitherapeutic regimen is needed to treat different stages in the spectrum of this disease.
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Key Words
- AA, Arachidonic acid
- ADH, Alcohol dehydrogenase
- AH, Alcoholic hepatitis
- ALD, Alcohol-associated liver disease
- ALDH, Aldehyde dehydrogenase
- ALT, Alanine transaminase
- ASH, Alcohol-associated steatohepatitis
- AST, Aspartate transaminase
- AUD, Alcohol use disorder
- BHMT, Betaine-homocysteine-methyltransferase
- CD, Cluster of differentiation
- COX, Cycloxygenase
- CTLs, Cytotoxic T-lymphocytes
- CYP, Cytochrome P450
- CYP2E1, Cytochrome P450 2E1
- Cu/Zn SOD, Copper/zinc superoxide dismutase
- DAMPs, Damage-associated molecular patterns
- DC, Dendritic cells
- EDN1, Endothelin 1
- ER, Endoplasmic reticulum
- ETOH, Ethanol
- EVs, Extracellular vesicles
- FABP4, Fatty acid-binding protein 4
- FAF2, Fas-associated factor family member 2
- FMT, Fecal microbiota transplant
- Fn14, Fibroblast growth factor-inducible 14
- GHS-R1a, Growth hormone secretagogue receptor type 1a
- GI, GOsteopontinastrointestinal tract
- GSH Px, Glutathione peroxidase
- GSSG Rdx, Glutathione reductase
- GST, Glutathione-S-transferase
- GWAS, Genome-wide association studies
- H2O2, Hydrogen peroxide
- HA, Hyaluronan
- HCC, Hepatocellular carcinoma
- HNE, 4-hydroxynonenal
- HPMA, 3-hydroxypropylmercapturic acid
- HSC, Hepatic stellate cells
- HSD17B13, 17 beta hydroxy steroid dehydrogenase 13
- HSP 90, Heat shock protein 90
- IFN, Interferon
- IL, Interleukin
- IRF3, Interferon regulatory factor 3
- JAK, Janus kinase
- KC, Kupffer cells
- LCN2, Lipocalin 2
- M-D, Mallory–Denk
- MAA, Malondialdehyde-acetaldehyde protein adducts
- MAT, Methionine adenosyltransferase
- MCP, Macrophage chemotactic protein
- MDA, Malondialdehyde
- MIF, Macrophage migration inhibitory factor
- Mn SOD, Manganese superoxide dismutase
- Mt, Mitochondrial
- NK, Natural killer
- NKT, Natural killer T-lymphocytes
- OPN, Osteopontin
- PAMP, Pathogen-associated molecular patterns
- PNPLA3, Patatin-like phospholipase domain containing 3
- PUFA, Polyunsaturated fatty acid
- RIG1, Retinoic acid inducible gene 1
- SAH, S-adenosylhomocysteine
- SAM, S-adenosylmethionine
- SCD, Stearoyl-CoA desaturase
- STAT, Signal transduction and activator of transcription
- TIMP1, Tissue inhibitor matrix metalloproteinase 1
- TLR, Toll-like receptor
- TNF, Tumor necrosis factor-α
- alcohol
- alcohol-associated liver disease
- ethanol metabolism
- liver
- miRNA, MicroRNA
- p90RSK, 90 kDa ribosomal S6 kinase
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Affiliation(s)
- Natalia A. Osna
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, 68105, USA
- Department of Internal Medicine, Omaha, NE, 68198, USA
| | - Karuna Rasineni
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, 68105, USA
- Department of Internal Medicine, Omaha, NE, 68198, USA
| | - Murali Ganesan
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, 68105, USA
- Department of Internal Medicine, Omaha, NE, 68198, USA
| | - Terrence M. Donohue
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, 68105, USA
- Department of Internal Medicine, Omaha, NE, 68198, USA
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Kusum K. Kharbanda
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, 68105, USA
- Department of Internal Medicine, Omaha, NE, 68198, USA
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198, USA
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Thomas AS, Sassi M, Angelini R, Morgan AH, Davies JS. Acylation, a Conductor of Ghrelin Function in Brain Health and Disease. Front Physiol 2022; 13:831641. [PMID: 35845996 PMCID: PMC9280358 DOI: 10.3389/fphys.2022.831641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/31/2022] [Indexed: 11/22/2022] Open
Abstract
Acyl-ghrelin (AG) is an orexigenic hormone that has a unique octanoyl modification on its third serine residue. It is often referred to as the “hunger hormone” due to its involvement in stimulating food intake and regulating energy homeostasis. The discovery of the enzyme ghrelin-O-acyltransferase (GOAT), which catalyses ghrelin acylation, provided further insights into the relevance of this lipidation process for the activation of the growth hormone secretagogue receptor (GHS-R) by acyl-ghrelin. Although acyl-ghrelin is predominantly linked with octanoic acid, a range of saturated fatty acids can also bind to ghrelin possibly leading to specific functions. Sources of ghrelin acylation include beta-oxidation of longer chain fatty acids, with contributions from fatty acid synthesis, the diet, and the microbiome. In addition, both acyl-ghrelin and unacyl-ghrelin (UAG) have feedback effects on lipid metabolism which in turn modulate their levels. Recently we showed that whilst acyl-ghrelin promotes adult hippocampal neurogenesis and enhances memory function, UAG inhibits these processes. As a result, we postulated that the circulating acyl-ghrelin:unacyl-ghrelin (AG:UAG) ratio might be an important regulator of neurogenesis and cognition. In this review, we discuss emerging evidence behind the relevance of ghrelin acylation in the context of brain physiology and pathology, as well as the current challenges of identifying the provenance of the acyl moiety.
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Bukhari SNA. An insight into the multifunctional role of ghrelin and structure activity relationship studies of ghrelin receptor ligands with clinical trials. Eur J Med Chem 2022; 235:114308. [PMID: 35344905 DOI: 10.1016/j.ejmech.2022.114308] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 02/06/2022] [Accepted: 03/18/2022] [Indexed: 11/30/2022]
Abstract
Ghrelin is a multifunctional gastrointestinal acylated peptide, primarily synthesized in the stomach and regulates the secretion of growth hormone and energy homeostasis. It plays a central role in modulating the diverse biological, physiological and pathological functions in vertebrates. The synthesis of ghrelin receptor ligands after the finding of growth hormone secretagogue developed from Met-enkephalin led to reveal the endogenous ligand ghrelin and the receptors. Subsequently, many peptides, small molecules and peptidomimetics focusing on the ghrelin receptor, GHS-R1a, were derived. In this review, the key features of ghrelin's structure, forms, its bio-physiological functions, pathological roles and therapeutic potential have been highlighted. A few peptidomimetics and pseudo peptide synthetic perspectives have also been discussed to make ghrelin receptor ligands, clinical trials and their success.
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Affiliation(s)
- Syed Nasir Abbas Bukhari
- Department of Pharmaceutical Chemistry, College of Pharmacy, Jouf University, Sakaka, Aljouf, 2014, Saudi Arabia.
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Lovell AJ, Hoecht EM, Hucik B, Cervone DT, Dyck DJ. The effects of diet and chronic exercise on skeletal muscle ghrelin response. Metabol Open 2022; 14:100182. [PMID: 35340718 PMCID: PMC8942827 DOI: 10.1016/j.metop.2022.100182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 11/20/2022] Open
Abstract
Background Recent findings indicate that ghrelin, particularly the unacylated form (UnAG), acutely stimulates skeletal muscle fatty acid oxidation (FAO) and can preserve insulin signaling and insulin-stimulated glucose uptake in the presence of high concentrations of saturated fatty acids. However, we recently reported that the stimulatory effect of ghrelin on FAO and subsequent ability to protect insulin stimulated glucose uptake was lost following 6-weeks (6w) of chronic high fat feeding. In the current study we examined the effects of both short-term 5 day (5d) and chronic 6w high-fat diet (HFD) on muscle ghrelin response, and whether exercise training could prevent the development of muscle ghrelin resistance with 6w of HFD Methods and Results Soleus muscle strips were isolated from male rats to determine the direct effects of acylated (AG) and UnAG isoforms on FAO and glucose uptake. A 5d HFD did not alter the response of soleus muscle to AG or UnAG. Conversely, 6w of HFD was associated with a loss of ghrelin's ability to stimulate FAO and protect insulin stimulated glucose uptake. Muscle response to UnAG remained intact following the 6w HFD with chronic exercise training. Unexpectedly, muscle response to both AG and UnAG was also lost after 6w of low-fat diet (LFD) consumption. Protein content of the classic ghrelin receptor, GHS-R1a, was not affected by diet or training. Corticotropin-releasing hormone receptor-2 (CRF-2R) content, a putative receptor for ghrelin in muscle, was significantly decreased in soleus from 6w HFD-fed animals and increased following exercise training. This may explain the protection of UnAG response with training in HFD-fed rats but does not explain why ghrelin response was also lost in LFD-fed animals. Conclusions UnAG protects muscle glucose uptake during acute lipid oversupply, likely due to its ability to stimulate FAO. This effect is lost in 6w HFD-fed animals but protected with exercise training. Unexpectedly, ghrelin response was lost in 6w LFD-fed animals. The loss of ghrelin response in muscle with a LFD cannot be explained by a change in putative ghrelin receptor content. We believe that the sedentary nature of the animals is a major factor in the development of muscle ghrelin resistance and warrants further research. Ghrelin stimulates fatty acid oxidation in skeletal muscle. This stimulation is strongly associated with protection from acute fat overload. Prolonged sedentary behaviour and a high fat diet impair ghrelin's ability to stimulate fatty acid oxidation. Exercise training preserves ghrelin's positive effects on skeletal muscle.
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Zang P, Yang CH, Liu J, Lei HY, Wang W, Guo QY, Lu B, Shao JQ. Relationship Between Acyl and Desacyl Ghrelin Levels with Insulin Resistance and Body Fat Mass in Type 2 Diabetes Mellitus. Diabetes Metab Syndr Obes 2022; 15:2763-2770. [PMID: 36105430 PMCID: PMC9464628 DOI: 10.2147/dmso.s368770] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 08/22/2022] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Although strong evidence suggests that ghrelin plays an important role in regulating energy balance, the effects of acylated ghrelin (AG) and deacylated ghrelin (DAG) on fat mass are largely undefined. This study aimed to investigate the differential associations of both forms of ghrelin with insulin resistance and body fat mass in patients with type 2 diabetes mellitus (T2DM). PATIENTS AND METHODS A total of 162 patients with type 2 diabetes were recruited and classified based on BMI and visceral fat area (VFA) as VFA normal group (n = 78), normal-BMI VFA obesity group (n = 20) and high-BMI VFA obesity group (n = 64). VFA and subcutaneous fat area (SFA) were detected by bioelectrical impedance analysis. Blood samples were collected to measure fasting glucose, insulin, lipids, AG and DAG levels after clinical examination. RESULTS Compared with VFA normal group, DAG levels were significantly lower (421.7 ± 106.0 and 388.7 ± 96.5 pg/mL vs 524.4 ± 141.5 pg/mL, P < 0.01) in the two VFA obesity groups. No significant difference was found in AG levels within three groups. Among all subjects, BMI, VFA, SFA, fasting insulin and HOMA-IR were negatively correlated with DAG but positively with AG/DAG ratio (P < 0.01). In contrast, AG was positively correlated with HOMA-IR and fasting glucose (P < 0.01). Multiple stepwise regression analysis showed that fasting glucose was the independent factor of AG, VFA and HOMA-IR were the independent factors related to DAG. CONCLUSION DAG levels have a strong negative association with excess body fat mass and insulin resistance, whereas AG levels are closely related to elevated blood glucose levels in T2DM patients.
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Affiliation(s)
- Pu Zang
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
| | - Cui-Hua Yang
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
| | - Jun Liu
- Department of Endocrinology, Jinling Hospital, Southern Medical University, Nanjing, People’s Republic of China
| | - Hai-Yan Lei
- Department of Endocrinology, Jinling Hospital, Southern Medical University, Nanjing, People’s Republic of China
| | - Wei Wang
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
| | - Qing-Yu Guo
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
| | - Bin Lu
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
| | - Jia-Qing Shao
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
- Correspondence: Jia-Qing Shao, Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing, People’s Republic of China, Tel +86-25-80860354, Email
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Song X, Wang M, Jiao H, Zhao J, Wang X, Lin H. Ghrelin is a signal to facilitate the utilization of fatty acids and save glucose by the liver, skeletal muscle, and adipose tissues in chicks. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1867:159081. [PMID: 34856413 DOI: 10.1016/j.bbalip.2021.159081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/29/2021] [Accepted: 11/09/2021] [Indexed: 12/14/2022]
Abstract
Ghrelin, classically known as a central appetite-stimulating hormone, has recently been recognized to play an important role in peripheral tissue energy metabolism. In chicken, contrary to mammal, ghrelin acts as an anorexia signal, increased by fasting and further elevated after refed. In the present study, the effect of ghrelin on glucose/lipid utilization by peripheral tissues was investigated. Injection of exogenous acyl ghrelin reduced plasma triglyceride and glucose levels of chickens at both fasting and fed status. In the in vitro cultured chicken primary hepatocytes, adipocytes, and myoblasts, ghrelin suppressed glucose uptake, stimulated fatty acids uptake and oxidation, and decreased TG content. In hepatocyte, ghrelin increased the activities of LPL and HL, and upregulated the expression levels of gene ACC, CPT1, and PPARα. Ghrelin treatment markedly increased the protein level of p-ACC, PPARγ, PGC1α, and CPT1 in hepatocytes, adipocytes and myoblasts. Inhibition of AMPK activity by Compound C had no influence on glucose uptake by hepatocyte, adipocyte, and myoblast, but further amplified the stimulated fatty acid uptake of adipocyte by ghrelin. The present result demonstrates that ghrelin facilitates the uptake and oxidation of fatty acid and cut down the utilization of glucose by the liver, muscle, and adipose tissues. The result suggests that ghrelin functions as a signal of fatty acid oxidation. The study provides a vital framework for understanding the intrinsic role of ghrelin as a crucial factor in the concerted regulation of metabolic substrate of hepatocytes, adipocytes, and myoblasts.
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Affiliation(s)
- Xixi Song
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, No. 61 Daizong Street, Tai'an 271018, China; School of Sport Social Science, Shandong Sport University, No. 10600 Shiji Street, Jinan 250100, China
| | - Minghui Wang
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, No. 61 Daizong Street, Tai'an 271018, China
| | - Hongchao Jiao
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, No. 61 Daizong Street, Tai'an 271018, China
| | - Jingpeng Zhao
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, No. 61 Daizong Street, Tai'an 271018, China
| | - Xiaojuan Wang
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, No. 61 Daizong Street, Tai'an 271018, China
| | - Hai Lin
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, No. 61 Daizong Street, Tai'an 271018, China.
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Hucik B, Lovell AJ, Hoecht EM, Cervone DT, Mutch DM, Dyck DJ. Regulation of adipose tissue lipolysis by ghrelin is impaired with high-fat diet feeding and is not restored with exercise. Adipocyte 2021; 10:338-349. [PMID: 34224298 PMCID: PMC8259717 DOI: 10.1080/21623945.2021.1945787] [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] [Indexed: 11/28/2022] Open
Abstract
Ghrelin is released from the stomach as an anticipatory signal prior to a meal and decreases immediately after. Previous research has shown that both acylated (AG) and unacylated (UnAG) ghrelin blunt adrenoreceptor-stimulated lipolysis in rat white adipose tissue (WAT) ex vivo. We investigated whether acute or chronic consumption of a high fat diet (HFD) impaired the ability of ghrelin to regulate adipose tissue lipolysis, and if this impairment could be restored with exercise. After 5 days (5d) of a HFD, or 6 weeks (6 w) of a HFD (60% kcal from fat) with or without exercise training, inguinal and retroperitoneal WAT was collected from anesthetized rats for adipose tissue organ culture. Samples were treated with 1 μM CL 316,243 (CL; lipolytic control), 1 μM CL+150 ng/ml AG or 1 μM CL+150 ng/ml UnAG. Incubation media and tissue were collected after 2 hours. Colorometric assays were used to determine glycerol and free fatty acid (FFA) concentrations in media. Western blots were used to quantify the protein content of lipolytic enzymes and ghrelin receptors in both depots. CL stimulated lipolysis was evidenced by increases in glycerol (p < 0.0001) and FFA (p < 0.0001) concentrations in media compared to control. AG decreased CL-stimulated glycerol release in inguinal WAT from 5d LFD rats (p = 0.0097). Neither AG nor UnAG blunted lipolysis in adipose tissue from 5d or 6 w HFD-fed rats, and exercise did not restore ghrelin’s anti-lipolytic ability in 6 w HFD-fed rats. Overall, this study demonstrates that HFD consumption impairs ghrelin’s ability to regulate adipose tissue lipolysis.
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Affiliation(s)
- Barbora Hucik
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Andrew J. Lovell
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Evan M. Hoecht
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Daniel T. Cervone
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - David M. Mutch
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - David J. Dyck
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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Kärkkäinen O, Farokhnia M, Klåvus A, Auriola S, Lehtonen M, Deschaine SL, Piacentino D, Abshire KM, Jackson SN, Leggio L. Effect of intravenous ghrelin administration, combined with alcohol, on circulating metabolome in heavy drinking individuals with alcohol use disorder. Alcohol Clin Exp Res 2021; 45:2207-2216. [PMID: 34590334 PMCID: PMC8642277 DOI: 10.1111/acer.14719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/30/2021] [Accepted: 09/14/2021] [Indexed: 12/11/2022]
Abstract
BACKGROUND Ghrelin may influence several alcohol-related behaviors in animals and humans by modulating central and/or peripheral biological pathways. The aim of this exploratory analysis was to investigate associations between ghrelin administration and the human circulating metabolome during alcohol exposure in nontreatment seeking, heavy drinking individuals with alcohol use disorder (AUD). METHODS We used serum samples from a randomized, crossover, double-blind, placebo-controlled human laboratory study with intravenous (IV) ghrelin or placebo infusion in two experiments. During each session, participants received a loading dose (3 µg/kg) followed by continuous infusion (16.9 ng/kg/min) of acyl ghrelin or placebo. The first experiment included an IV alcohol self-administration (IV-ASA) session and the second experiment included an IV alcohol clamp (IV-AC) session, both with the counterbalanced infusion of ghrelin or placebo. Serum metabolite profiles were analyzed from repeated blood samples collected during each session. RESULTS In both experiments, ghrelin infusion was associated with an altered serum metabolite profile, including significantly increased levels of cortisol (IV-ASA q-value = 0.0003 and IV-AC q < 0.0001), corticosterone (IV-ASA q = 0.0202 and IV-AC q < 0.0001), and glycochenodeoxycholic acid (IV-ASA q = 0.0375 and IV-AC q = 0.0013). In the IV-ASA experiment, ghrelin infusion increased levels of cortisone (q = 0.0352) and fatty acids 18:1 (q = 0.0406) and 18:3 (q = 0.0320). Moreover, in the IV-AC experiment, ghrelin infusion significantly increased levels of glycocholic acid (q < 0.0001) and phenylalanine (q = 0.0458). CONCLUSION IV ghrelin infusion, combined with IV alcohol administration, was associated with increases in the circulating metabolite levels of corticosteroids and glycine-conjugated bile acids, among other changes. Further research is needed to understand the role that metabolomic changes play in the complex interaction between ghrelin and alcohol.
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Affiliation(s)
- Olli Kärkkäinen
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1, 70210, Kuopio, Finland
| | - Mehdi Farokhnia
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, Baltimore and Bethesda, Maryland, USA
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Anton Klåvus
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Yliopistonranta 1, 70210, Kuopio, Finland
| | - Seppo Auriola
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1, 70210, Kuopio, Finland
| | - Marko Lehtonen
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1, 70210, Kuopio, Finland
| | - Sara L. Deschaine
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, Baltimore and Bethesda, Maryland, USA
| | - Daria Piacentino
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, Baltimore and Bethesda, Maryland, USA
- Center on Compulsive Behaviors, National Institutes of Health, Bethesda, MD, USA
| | - Kelly M. Abshire
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, Baltimore and Bethesda, Maryland, USA
| | - Shelley N. Jackson
- Translational Analytical Core, National Institute on Drug Abuse Intramural Research Program, Baltimore, Maryland, USA
| | - Lorenzo Leggio
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, Baltimore and Bethesda, Maryland, USA
- Center on Compulsive Behaviors, National Institutes of Health, Bethesda, MD, USA
- Translational Analytical Core, National Institute on Drug Abuse Intramural Research Program, Baltimore, Maryland, USA
- Medication Development Program, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
- Center for Alcohol and Addiction Studies, Department of Behavioral and Social Sciences, Brown University, Providence, RI, USA
- Division of Addiction Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
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Epigenetic mapping of the somatotropic axis in Nile tilapia reveals differential DNA hydroxymethylation marks associated with growth. Genomics 2021; 113:2953-2964. [PMID: 34214627 PMCID: PMC7611323 DOI: 10.1016/j.ygeno.2021.06.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/02/2021] [Accepted: 06/25/2021] [Indexed: 12/29/2022]
Abstract
In vertebrates, the somatotropic axis comprising the pituitary gland, liver and muscle plays a major role in myogenesis. Its output in terms of muscle growth is highly affected by nutritional and environmental cues, and thus likely epigenetically regulated. Hydroxymethylation is emerging as a DNA modification that modulates gene expression but a holistic characterization of the hydroxymethylome of the somatotropic axis has not been investigated to date. Using reduced representation 5-hydroxymethylcytosine profiling we demonstrate tissue-specific localization of 5-hydroxymethylcytosines at single nucleotide resolution. Their abundance within gene bodies and promoters of several growth-related genes supports their pertinent role in gene regulation. We propose that cytosine hydroxymethylation may contribute to the phenotypic plasticity of growth through epigenetic regulation of the somatotropic axis.
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The effect of omega3 fatty acid supplementation on PPARγ and UCP2 expressions, resting energy expenditure, and appetite in athletes. BMC Sports Sci Med Rehabil 2021; 13:48. [PMID: 33964966 PMCID: PMC8106165 DOI: 10.1186/s13102-021-00266-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 04/05/2021] [Indexed: 11/16/2022]
Abstract
Background Omega3 fatty acids as a ligand of energy-related genes, have a role in metabolism, and energy expenditure. These effects are due to changes in the expression of peroxisome proliferator-activated receptor-gamma (PPARγ) and uncoupling protein2 (UCP2). This study evaluated the effect of omega3 supplements on PPARγ mRNA expression and UCP2 mRNA expression and protein levels, as regulators of energy metabolism, resting energy expenditure (REE), and appetite in athletes. Methods In a 3-week double-blind RCT in Tabriz, Iran, in 2019, 36 male athletes, age 21.86 (±3.15) y with 16.17 (±5.96)% body fat were randomized to either an intervention (2000 mg/day omega3; EPA: 360, DHA: 240) or placebo (2000 mg/day edible paraffin) groups. Appetite and REE were assessed before and after the intervention. PPARγ and UCP2 mRNA expression and UCP2 protein levels in blood were evaluated by standard methods. Results Results showed PPARγ mRNA levels, and UCP2 mRNA and protein levels increased in omega3 group (p < 0.05), as did REE (p < 0.05). Also, differences in the sensation of hunger or satiety were significant (p < 0.05). Conclusions Our findings showed that omega3 supplementation leads to the up-regulation of PPARγ and UCP2 expressions as the indicators of metabolism in healthy athletes.
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Elbaz M, Gershon E. Ghrelin, via corticotropin-releasing factor receptors, reduces glucose uptake and increases lipid content in mouse myoblasts cells. Physiol Rep 2021; 9:e14654. [PMID: 33463908 PMCID: PMC7814488 DOI: 10.14814/phy2.14654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 10/27/2020] [Accepted: 10/27/2020] [Indexed: 12/20/2022] Open
Abstract
Ghrelin and the corticotropin-releasing factor (CRF) family are known regulators of cellular metabolism and energy balance. We previously demonstrated that myoblast glucose metabolism is regulated by ghrelin and that this effect is mediated by CRF receptor type 2 (CRF-R2). Here we explored the effect of des-acyl ghrelin, the major circulating isoform of ghrelin, on cellular metabolism in mouse myoblast C2C12 cells, and examined whether CRF family receptors mediate its metabolic effects in muscle cells. C2C12 cells were exposed to des-acyl ghrelin with or without the CRF-R1- and CRF-R2-specific antagonists antalarmin or antisauvagine-30, respectively. Des-acyl ghrelin reduced glucose uptake and expression of the glucose transporter GLUT4, but induced retinol-binding protein 4 (RBP4) expression. Antalarmin and antisauvagine-30 inhibited the induction of glucose uptake by des-acyl ghrelin and its effect on GLUT4 and RBP4 expression. Moreover, treating C2C12 cells with des-acyl ghrelin resulted in cAMP activation in response to the CRF-R1-specific ligand stressin, and the CRF-R2-specific ligand Ucn3. Furthermore, des-acyl ghrelin reduced the expression of uncoupling proteins UCP2 and UCP3. Adding antalarmin or antisauvagine-30 to the medium reversed this effect. Finally, des-acyl ghrelin elevated lipid content and acetyl-CoA carboxylase expression in C2C12 cells. Our results suggest that during food deprivation, des-acyl ghrelin signals the muscle cells that glucose levels are low and that they should switch to fatty acids for their metabolic fuel.
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Affiliation(s)
- Michal Elbaz
- Department of Ruminant ScienceAgricultural Research OrganizationRishon LeZionIsrael
| | - Eran Gershon
- Department of Ruminant ScienceAgricultural Research OrganizationRishon LeZionIsrael
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20
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Su M, Yan M, Yao J, Fang Y, Jin H, Gong Y. Unacylated Ghrelin Regulates Glucose-Sensitive Neurons Activity and Glycolipid Metabolism via Orexin-A Neurons in the Lateral Hypothalamic Area. Horm Metab Res 2020; 52:747-754. [PMID: 32731263 DOI: 10.1055/a-1207-1212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The objective of the study was to investigate the regulatory actions of unacylated ghrelin (UAG) on glucose-sensitive (GS) neurons and glycolipid metabolism in the lateral hypothalamus area (LHA) and its involvement with orexin-A-immunopositive neurons. The effects of UAG administered into the LHA on GS neurons discharges and glycolipid metabolism were detected by single neuron discharge recording, biochemical index analysis and quantitative real-time PCR; the level of c-fos protein in orexin-A-immunopositive neurons was observed using immunofluorescence staining. UAG microinjected into the LHA activated glucose-inhibited neurons, which were partially blocked by pre-administration of anti-orexin-A antibody in the LHA. Furthermore, UAG microinjected into the LHA significantly reduced serum triglycerides (TG), total cholesterol, low-density lipoprotein cholesterol, blood glucose, insulin and hepatic TG levels, while elevated serum high-density lipoprotein cholesterol levels. UAG elevated the mRNA expression of carnitine palmitoyltransferase-1 and reduced the mRNA expression of acetyl-CoA carboxylase-1 in the liver. The above-mentioned effects of UAG were partially blocked by pre-administration of anti-orexin-A antibody. The expressions of orexin-A and c-fos were observed in the LHA. After UAG injection into the LHA, some neurons showed double labeling, and the percentage of double-labeled orexin-A/c-fos neurons in orexin-A-immunopositive neurons increased significantly. UAG in the LHA regulates glycolipid metabolism by activating orexin-A-immunopositive neurons in the LHA.
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Affiliation(s)
- Manqing Su
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China
| | - Meixing Yan
- Qingdao Women and Children's Hospital, Qingdao, China
| | - Jiatong Yao
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China
| | - Yanpeng Fang
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China
| | - Hong Jin
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China
| | - Yanling Gong
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China
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Kim S, Nam Y, Shin SJ, Park YH, Jeon SG, Kim JI, Kim MJ, Moon M. The Potential Roles of Ghrelin in Metabolic Syndrome and Secondary Symptoms of Alzheimer's Disease. Front Neurosci 2020; 14:583097. [PMID: 33071750 PMCID: PMC7543232 DOI: 10.3389/fnins.2020.583097] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022] Open
Abstract
Although the major causative factors of Alzheimer's disease (AD) are the accumulation of amyloid β and hyperphosphorylated tau, AD can also be caused by metabolic dysfunction. The major clinical symptom of AD is cognitive dysfunction. However, AD is also accompanied by various secondary symptoms such as depression, sleep-wake disturbances, and abnormal eating behaviors. Interestingly, the orexigenic hormone ghrelin has been suggested to have beneficial effects on AD-related metabolic syndrome and secondary symptoms. Ghrelin improves lipid distribution and alters insulin sensitivity, effects that are hypothesized to delay the progression of AD. Furthermore, ghrelin can relieve depression by enhancing the secretion of hormones such as serotonin, noradrenaline, and orexin. Moreover, ghrelin can upregulate the expression of neurotrophic factors such as brain-derived neurotrophic factor and modulate the release of proinflammatory cytokines such as tumor necrosis factor α and interleukin 1β. Ghrelin alleviates sleep-wake disturbances by increasing the levels of melatonin, melanin-concentrating hormone. Ghrelin reduces the risk of abnormal eating behaviors by increasing neuropeptide Y and γ-aminobutyric acid. In addition, ghrelin increases food intake by inhibiting fatty acid biosynthesis. However, despite the numerous studies on the role of ghrelin in the AD-related pathology and metabolic disorders, there are only a few studies that investigate the effects of ghrelin on secondary symptoms associated with AD. In this mini review, our purpose is to provide the insights of future study by organizing the previous studies for the role of ghrelin in AD-related pathology and metabolic disorders.
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Affiliation(s)
- Sujin Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Yunkwon Nam
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Soo Jung Shin
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Yong Ho Park
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Seong Gak Jeon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea.,Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Jin-Il Kim
- Department of Nursing, College of Nursing, Jeju National University, Jeju-si, South Korea
| | - Min-Jeong Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Minho Moon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
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Dagher-Hamalian C, Stephan J, Zeeni N, Harhous Z, Shebaby WN, Abdallah MS, Faour WH. Ghrelin-induced multi-organ damage in mice fed obesogenic diet. Inflamm Res 2020; 69:1019-1026. [PMID: 32719925 DOI: 10.1007/s00011-020-01383-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE AND DESIGN Ghrelin has a key role in modulating energy metabolism and weight gain. The present study aimed at studying the potential role of ghrelin in the development and/or exacerbation of organ damage in a mouse model of diet-induced obesity. OBJECTIVE AND DESIGN Adult mice were fed one of two diets for 20 weeks: standard high carbohydrate (HC) or high-fat high-sugar (HFHS). Starting week 17, the animals were given regular intraperitoneal ghrelin (160 µg/kg) or saline injections Abdominal fat, serum creatinine, and glucose levels, as well as kidney, liver and heart weight and pathology were assessed. RESULTS Ghrelin-injected mice showed significant organ damage, which was more exacerbated in HFHS-fed animals. While the HFHS diet was associated with significant liver damage, ghrelin administration did not reverse it. Interestingly, ghrelin administration induced moderate kidney damage and significantly affected the heart by increasing perivascular and myocardium fibrosis, steatosis as well as inflammation. Moreover, serum creatinine levels were higher in the animal group injected with ghrelin. CONCLUSION Ghrelin administration was associated with increased functional and structural organ damage, regardless of diet. The present study provides novel evidence of multi-organ physiologic alterations secondary to ghrelin administration.
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Affiliation(s)
- Carole Dagher-Hamalian
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Joseph Stephan
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Nadine Zeeni
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Zeina Harhous
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Wassim N Shebaby
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Maya S Abdallah
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Wissam H Faour
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon.
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23
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Barazzoni R, Gortan Cappellari G, Zanetti M, Klaus KA, Semolic A, Johnson ML, Nair KS. Higher unacylated ghrelin and insulin sensitivity following dietary restriction and weight loss in obese humans. Clin Nutr 2020; 40:638-644. [PMID: 32641220 DOI: 10.1016/j.clnu.2020.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 05/27/2020] [Accepted: 06/15/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND & AIMS Unacylated ghrelin (UnAG) modulates insulin sensitivity. Low plasma UnAG occurs in obesity and potentially contributes to obesity-associated insulin resistance. We hypothesized that improvements in insulin sensitivity in obese people induced by moderate caloric restriction (CR) may be paralleled and at least in part explained by concurrent increases in UnAG levels. METHODS 20 general community obese people were randomly assigned to 16-week CR (n = 11) or control diet (n = 9). We investigated the impact of CR on the interaction between insulin sensitivity changes [area under the curve (AUCg) of glucose infusion to maintain euglycemia during hyperinsulinemic-euglycemic clamp] and plasma total (TotalG), acylated (AG) and Unacylated ghrelin (UnAG). Plasma pro-inflammatory tumor necrosis factor alpha (TNFα) and anti-inflammatory interleukin-10 (IL-10) were also measured since changes in inflammation may contribute to UnAG activities. RESULTS CR reduced BMI and increased insulin sensitivity (p < 0.05). TotalG and UnAG but not AG increased in CR but not in Control (p < 0.05). Il-10 and IL-10/TNFα ratio also increased in CR (p < 0.05). Changes in UnAG were positively associated with changes in AUCg in all subjects (n = 20; p < 0.01) also after adjustment for treatment and changes in BMI and cytokines. CONCLUSIONS Caloric restriction modifies circulating ghrelin profile with selective increase in unacylated hormone in obese individuals. The current study supports the hypothesis that higher unacylated ghrelin contributes to improvements in insulin sensitivity following diet-induced weight loss in human obesity.
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Affiliation(s)
- Rocco Barazzoni
- Dept. of Medical, Surgical and Health Sciences - University of Trieste, Italy and Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Trieste, Italy.
| | - Gianluca Gortan Cappellari
- Dept. of Medical, Surgical and Health Sciences - University of Trieste, Italy and Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Trieste, Italy
| | - Michela Zanetti
- Dept. of Medical, Surgical and Health Sciences - University of Trieste, Italy and Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Trieste, Italy
| | - Katherine A Klaus
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN, USA
| | - Annamaria Semolic
- Dept. of Medical, Surgical and Health Sciences - University of Trieste, Italy and Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Trieste, Italy
| | - Matthew L Johnson
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN, USA
| | - K Sreekumaran Nair
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN, USA.
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Abstract
Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are two of the most common liver diseases associated with obesity, type 2 diabetes and metabolic syndrome. The prevalence of these conditions are increasingly rising and presently there is not a pharmacological option available in the market. Elucidation of the mechanism of action and the molecular underpinnings behind liver disease could help to better understand the pathophysiology of these illnesses. In this sense, in the last years modulation of the ghrelin system in preclinical animal models emerge as a promising therapeutic tool. In this review, we compile the latest knowledge of the modulation of ghrelin system and its intracellular pathways that regulates lipid metabolism, hepatic inflammation and liver fibrosis. We also describe novel processes implicated in the regulation of liver disease by ghrelin, such as autophagy or dysregulated circadian rhythms. In conclusion, the information displayed in this review support that the ghrelin system could be an appealing strategy for the treatment of liver disease.
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Affiliation(s)
- Mar Quiñones
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Santiago de Compostela, Spain
| | - Johan Fernø
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Omar Al-Massadi
- Inserm UMR-S1270, 75005, Paris, France.
- Faculté des Sciences et d'Ingénierie, Sorbonne Université, 75005, Paris, France.
- Institut du Fer a Moulin, Inserm, 17 rue du Fer à Moulin, 75005, Paris, France.
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25
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Unacylated ghrelin stimulates fatty acid oxidation to protect skeletal muscle against palmitate-induced impairment of insulin action in lean but not high-fat fed rats. Metabol Open 2020; 5:100026. [PMID: 32812929 PMCID: PMC7424793 DOI: 10.1016/j.metop.2020.100026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/28/2020] [Accepted: 01/29/2020] [Indexed: 11/29/2022] Open
Abstract
Background Ghrelin is a gut hormone that spikes in circulation before mealtime. Recent findings suggest that both ghrelin isoforms stimulate skeletal muscle fatty acid oxidation, lending to the possibility that it may regulate skeletal muscle’s handling of meal-derived substrates. It was hypothesized in the current study that ghrelin may preserve muscle insulin response during conditions of elevated saturated fatty acid (palmitate) availability by promoting its oxidation. Methods and results Soleus muscle strips were isolated from male rats to determine the direct effects of ghrelin isoforms on fatty acid oxidation, glucose uptake and insulin signaling. We demonstrate that unacylated ghrelin (UnAG) is the more potent stimulator of skeletal muscle fatty acid oxidation. Both isoforms of ghrelin generally protected muscle from impaired insulin-mediated phosphorylation of AKT Ser473 and Thr308, as well as downstream phosphorylation of AS160 Ser588 during high palmitate exposure. However, only UnAG was able to preserve insulin-stimulated glucose uptake during exposure to high palmitate concentrations. The use of etomoxir, an irreversible inhibitor of carnitine palmitoyltransferase (CPT-1) abolished this protection, strongly suggesting that UnAG’s stimulation of fatty acid oxidation may be essential to this protection. To our knowledge, we are also the first to investigate the impact of a chronic high-fat diet on ghrelin’s actions in muscle. Following 6 wks of a high-fat diet, UnAG was unable to preserve insulin-stimulated signaling or glucose transport during an acute high palmitate exposure. UnAG was also unable to further stimulate 5′ AMP-activated protein kinase (AMPK) or fatty acid oxidation during high palmitate exposure. Corticotropin-releasing hormone receptor-2 (CRF-2R) content was significantly decreased in muscle from high-fat fed animals, which may partially account for the loss of UnAG’s effects. Conclusions UnAG is able to protect muscle from acute lipid exposure, likely due to its ability to stimulation fatty acid oxidation. This effect is lost in high-fat fed animals, implying a resistance to ghrelin at the level of the muscle. The underlying mechanisms accounting for ghrelin resistance in high fat-fed animals remain to be discovered. Saturated lipids acutely impair muscle insulin signaling and glucose transport. Ghrelin isoforms consistently protect insulin signaling from lipid detriment. Unacylated ghrelin more potently stimulates fat oxidation, preserving glucose transport. Muscle of chronic high fat-fed rats may be resistant to ghrelin’s metabolic effects.
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26
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Akalu Y, Molla MD, Dessie G, Ayelign B. Physiological Effect of Ghrelin on Body Systems. Int J Endocrinol 2020; 2020:1385138. [PMID: 32565790 PMCID: PMC7267865 DOI: 10.1155/2020/1385138] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 02/08/2020] [Accepted: 05/13/2020] [Indexed: 02/06/2023] Open
Abstract
Ghrelin is a relatively novel multifaceted hormone that has been found to exert a plethora of physiological effects. In this review, we found/confirmed that ghrelin has effect on all body systems. It induces appetite; promotes the use of carbohydrates as a source of fuel while sparing fat; inhibits lipid oxidation and promotes lipogenesis; stimulates the gastric acid secretion and motility; improves cardiac performance; decreases blood pressure; and protects the kidneys, heart, and brain. Ghrelin is important for learning, memory, cognition, reward, sleep, taste sensation, olfaction, and sniffing. It has sympatholytic, analgesic, antimicrobial, antifibrotic, and osteogenic effects. Moreover, ghrelin makes the skeletal muscle more excitable and stimulates its regeneration following injury; delays puberty; promotes fetal lung development; decreases thyroid hormone and testosterone; stimulates release of growth hormone, prolactin, glucagon, adrenocorticotropic hormone, cortisol, vasopressin, and oxytocin; inhibits insulin release; and promotes wound healing. Ghrelin protects the body by different mechanisms including inhibition of unwanted inflammation and induction of autophagy. Having a clear understanding of the ghrelin effect in each system has therapeutic implications. Future studies are necessary to elucidate the molecular mechanisms of ghrelin actions as well as its application as a GHSR agonist to treat most common diseases in each system without any paradoxical outcomes on the other systems.
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Affiliation(s)
- Yonas Akalu
- Department of Physiology, School of Medicine, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Meseret Derbew Molla
- Department of Biochemistry, School of Medicine, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Gashaw Dessie
- Department of Biochemistry, School of Medicine, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Birhanu Ayelign
- Department of Immunology and Molecular Biology, School of Biomedical and Laboratory Science, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
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27
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McCauley HA. Enteroendocrine Regulation of Nutrient Absorption. J Nutr 2020; 150:10-21. [PMID: 31504661 DOI: 10.1093/jn/nxz191] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/19/2019] [Accepted: 07/23/2019] [Indexed: 12/14/2022] Open
Abstract
Enteroendocrine cells (EECs) in the intestine regulate many aspects of whole-body physiology and metabolism. EECs sense luminal and circulating nutrients and respond by secreting hormones that act on multiple organs and organ systems, such as the brain, gallbladder, and pancreas, to control satiety, digestion, and glucose homeostasis. In addition, EECs act locally, on enteric neurons, endothelial cells, and the gastrointestinal epithelium, to facilitate digestion and absorption of nutrients. Many recent reports raise the possibility that EECs and the enteric nervous system may coordinate to regulate gastrointestinal functions. Loss of all EECs results in chronic malabsorptive diarrhea, placing EECs in a central role regulating nutrient absorption in the gut. Because there is increasing evidence that EECs can directly modulate the efficiency of nutrient absorption, it is possible that EECs are master regulators of a feed-forward loop connecting appetite, digestion, metabolism, and abnormally augmented nutrient absorption that perpetuates metabolic disease. This review focuses on the roles that specific EEC hormones play on glucose, peptide, and lipid absorption within the intestine.
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Affiliation(s)
- Heather A McCauley
- Division of Developmental Biology and the Center for Stem Cell and Organoid Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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28
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Cervone DT, Sheremeta J, Kraft EN, Dyck DJ. Acylated and unacylated ghrelin directly regulate ß-3 stimulated lipid turnover in rodent subcutaneous and visceral adipose tissue ex vivo but not in vivo. Adipocyte 2019; 8:1-15. [PMID: 30265180 PMCID: PMC6768250 DOI: 10.1080/21623945.2018.1528811] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ghrelin has garnered interest as a gut-derived regulator of lipid metabolism, beyond its classical roles in driving appetite and growth hormone release. Ghrelin’s circulating concentrations follow an ultradian rhythm, peak immediately before a meal and point towards a potential metabolic role in reducing the mobilization of fatty acid stores in preparation for the storage of ingested food. Here, we demonstrate that both acylated and unacylated ghrelin have physiological roles in attenuating lipolysis in mature subcutaneous and visceral adipose tissue depots of rats. Ghrelin blunted the ß3-induction (CL 316, 243) of glycerol release (index of lipolysis) which coincided with a reduced activation of the key lipid hydrolase HSL at two of its serine residues (Ser563/660). Furthermore, ghrelin appeared to inhibit fatty acid reesterification in the presence of CL such that fatty acid concentrations in the surrounding media were maintained in spite of a reduction in lipolysis. Importantly, these aforementioned effects were not observed following ghrelin injection in vivo, as there was no attenuation of CL-induced glycerol release. This highlights the importance of exercising caution when interpreting the effects of administering ghrelin in vivo, and the necessity for uncovering the elusive mechanisms by which ghrelin regulates lipolysis and fatty acid reesterification. We conclude that both acylated and unacylated ghrelin can exert direct inhibitory effects on lipolysis and fatty acid reesterification in adipose tissue from rats. However, these effects are not observed in vivo and outline the complexity of studying ghrelin’s effects on fatty acid metabolism in the living animal.
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Affiliation(s)
- Daniel T. Cervone
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Justin Sheremeta
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Emily N. Kraft
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - David J. Dyck
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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29
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Corrêa da Silva F, Aguiar C, Pereira JAS, de Brito Monteiro L, Davanzo GG, Codo AC, Pimentel de Freitas L, Berti AS, Lopes Ferrucci D, Castelucci BG, Consonni SR, Carvalho HF, Moraes-Vieira PMM. Ghrelin effects on mitochondrial fitness modulates macrophage function. Free Radic Biol Med 2019; 145:61-66. [PMID: 31525456 DOI: 10.1016/j.freeradbiomed.2019.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/12/2019] [Accepted: 09/12/2019] [Indexed: 12/11/2022]
Abstract
Over the past years, systemic derived cues that regulate cellular metabolism have been implicated in the regulation of immune responses. Ghrelin is an orexigenic hormone produced by enteroendocrine cells in the gastric mucosa with known immunoregulatory roles. The mechanism behind the function of ghrelin in immune cells, such as macrophages, is still poorly understood. Here, we explored the hypothesis that ghrelin leads to alterations in macrophage metabolism thus modulating macrophage function. We demonstrated that ghrelin exerts an immunomodulatory effect over LPS-activated peritoneal macrophages, as evidenced by inhibition of TNF-α and IL-1β secretion and increased IL-12 production. Concomitantly, ghrelin increased mitochondrial membrane potential and increased respiratory rate. In agreement, ghrelin prevented LPS-induced ultrastructural damage in the mitochondria. Ghrelin also blunted LPS-induced glycolysis. In LPS-activated macrophages, glucose deprivation did not affect ghrelin-induced IL-12 secretion, whereas the inhibition of pyruvate transport and mitochondria-derived ATP abolished ghrelin-induced IL-12 secretion, indicating a dependence on mitochondrial function. Ghrelin pre-treatment of metabolic activated macrophages inhibited the secretion of TNF-α and enhanced IL-12 levels. Moreover, ghrelin effects on IL-12, and not on TNF-α, are dependent on mitochondria elongation, since ghrelin did not enhance IL-12 secretion in metabolic activated mitofusin-2 deficient macrophages. Thus, ghrelin affects macrophage mitochondrial metabolism and the subsequent macrophage function.
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Affiliation(s)
- Felipe Corrêa da Silva
- Laboratory of Immunometabolism, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas, Brazil
| | - Cristhiane Aguiar
- Laboratory of Immunometabolism, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas, Brazil
| | - Jéssica A S Pereira
- Laboratory of Immunometabolism, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas, Brazil; Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Brazil
| | - Lauar de Brito Monteiro
- Laboratory of Immunometabolism, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas, Brazil
| | - Gustavo Gastão Davanzo
- Laboratory of Immunometabolism, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas, Brazil
| | - Ana Campos Codo
- Laboratory of Immunometabolism, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas, Brazil
| | - Leonardo Pimentel de Freitas
- Laboratory of Immunometabolism, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas, Brazil
| | - Aline Siqueira Berti
- Laboratory of Extracellular Matrix, Department of Structural and Functional Biology, University of Campinas, Brazil
| | - Danilo Lopes Ferrucci
- Laboratory of Extracellular Matrix, Department of Structural and Functional Biology, University of Campinas, Brazil
| | - Bianca Gazieri Castelucci
- Laboratory of Cytochemistry and Immunocytochemistry, Department of Biochemistry and Tissue Biology, University of Campinas, Brazil
| | - Sílvio Roberto Consonni
- Laboratory of Cytochemistry and Immunocytochemistry, Department of Biochemistry and Tissue Biology, University of Campinas, Brazil
| | - Hernandes F Carvalho
- Laboratory of Extracellular Matrix, Department of Structural and Functional Biology, University of Campinas, Brazil
| | - Pedro M M Moraes-Vieira
- Laboratory of Immunometabolism, Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas, Brazil; Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Brazil.
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30
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Gortan Cappellari G, Barazzoni R. Ghrelin forms in the modulation of energy balance and metabolism. Eat Weight Disord 2019; 24:997-1013. [PMID: 30353455 DOI: 10.1007/s40519-018-0599-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/16/2018] [Indexed: 02/06/2023] Open
Abstract
Ghrelin is a gastric hormone circulating in acylated (AG) and unacylated (UnAG) forms. This narrative review aims at presenting current emerging knowledge on the impact of ghrelin forms on energy balance and metabolism. AG represents ~ 10% of total plasma ghrelin, has an appetite-stimulating effect and is the only form for which a receptor has been identified. Moreover, other metabolic AG-induced effects have been reported, including the modulation of glucose homeostasis with stimulation of liver gluconeogenesis, the increase of fat mass and the improvement of skeletal muscle mitochondrial function. On the other hand, UnAG has no orexigenic effects, however recent reports have shown that it is directly involved in the modulation of skeletal muscle energy metabolism by improving a cluster of interlinked functions including mitochondrial redox activities, tissue inflammation and insulin signalling and action. These findings are in agreement with human studies which show that UnAG circulating levels are positively associated with insulin sensitivity both in metabolic syndrome patients and in a large cohort from the general population. Moreover, ghrelin acylation is regulated by a nutrient sensor mechanism, specifically set on fatty acids availability. These recent findings consistently point towards a novel independent role of UnAG as a regulator of muscle metabolic pathways maintaining energy status and tissue anabolism. While a specific receptor for UnAG still needs to be identified, recent evidence strongly supports the hypothesis that the modulation of ghrelin-related molecular pathways, including those involved in its acylation, may be a potential novel target in the treatment of metabolic derangements in disease states characterized by metabolic and nutritional complications.Level of evidence Level V, narrative review.
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Affiliation(s)
- Gianluca Gortan Cappellari
- Department of Medical, Surgical and Health Sciences, University of Trieste, Strada di Fiume, 447, 34149, Trieste, Italy.
| | - Rocco Barazzoni
- Department of Medical, Surgical and Health Sciences, University of Trieste, Strada di Fiume, 447, 34149, Trieste, Italy.
- Azienda Sanitaria Universitaria Integrata di Trieste (ASUITS), Trieste, Italy.
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31
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Jeon SG, Hong SB, Nam Y, Tae J, Yoo A, Song EJ, Kim KI, Lee D, Park J, Lee SM, Kim JI, Moon M. Ghrelin in Alzheimer's disease: Pathologic roles and therapeutic implications. Ageing Res Rev 2019; 55:100945. [PMID: 31434007 DOI: 10.1016/j.arr.2019.100945] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/25/2019] [Accepted: 08/16/2019] [Indexed: 12/11/2022]
Abstract
Ghrelin, which has many important physiological roles, such as stimulating food intake, regulating energy homeostasis, and releasing insulin, has recently been studied for its roles in a diverse range of neurological disorders. Despite the several functions of ghrelin in the central nervous system, whether it works as a therapeutic agent for neurological dysfunction has been unclear. Altered levels and various roles of ghrelin have been reported in Alzheimer's disease (AD), which is characterized by the accumulation of misfolded proteins resulting in synaptic loss and cognitive decline. Interestingly, treatment with ghrelin or with the agonist of ghrelin receptor showed attenuation in several cases of AD-related pathology. These findings suggest the potential therapeutic implications of ghrelin in the pathogenesis of AD. In the present review, we summarized the roles of ghrelin in AD pathogenesis, amyloid beta (Aβ) homeostasis, tau hyperphosphorylation, neuroinflammation, mitochondrial deficit, synaptic dysfunction and cognitive impairment. The findings from this review suggest that ghrelin has a novel therapeutic potential for AD treatment. Thus, rigorously designed studies are needed to establish an effective AD-modifying strategy.
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32
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Rasineni K, Kubik JL, Casey CA, Kharbanda KK. Inhibition of Ghrelin Activity by Receptor Antagonist [d-Lys-3] GHRP-6 Attenuates Alcohol-Induced Hepatic Steatosis by Regulating Hepatic Lipid Metabolism. Biomolecules 2019; 9:biom9100517. [PMID: 31546643 PMCID: PMC6843513 DOI: 10.3390/biom9100517] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 01/13/2023] Open
Abstract
Alcoholic steatosis, characterized by an accumulation of triglycerides in hepatocytes, is one of the earliest pathological changes in the progression of alcoholic liver disease. In our previous study, we showed that alcohol-induced increase in serum ghrelin levels impair insulin secretion from pancreatic β-cells. The consequent reduction in the circulating insulin levels promote adipose-derived fatty acid mobilization to ultimately contribute to hepatic steatosis. In this study, we determined whether inhibition of ghrelin activity in chronic alcohol-fed rats could improve hepatic lipid homeostasis at the pancreas-adipose-liver axis. Adult Wistar rats were fed Lieber-DeCarli control or an ethanol liquid diet for 7 weeks. At 6 weeks, a subset of rats in each group were injected with either saline or ghrelin receptor antagonist, [d-Lys-3] GHRP-6 (DLys; 9 mg/kg body weight) for 5 days and all rats were sacrificed 2 days later. DLys treatment of ethanol rats improved pancreatic insulin secretion, normalized serum insulin levels, and the adipose lipid metabolism, as evidenced by the decreased serum free fatty acids (FFA). DLys treatment of ethanol rats also significantly decreased the circulating FFA uptake, de novo hepatic fatty acid synthesis ultimately attenuating alcoholic steatosis. To summarize, inhibition of ghrelin activity reduced alcoholic steatosis by improving insulin secretion, normalizing serum insulin levels, inhibiting adipose lipolysis, and preventing fatty acid uptake and synthesis in the liver. Our studies provided new insights on the important role of ghrelin in modulating the pancreas-adipose-liver, and promoting adipocyte lipolysis and hepatic steatosis. The findings offer a therapeutic approach of not only preventing alcoholic liver injury but also treating it.
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Affiliation(s)
- Karuna Rasineni
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.
- Research Service, Veterans' Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA.
| | - Jacy L Kubik
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.
- Research Service, Veterans' Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA.
| | - Carol A Casey
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.
- Research Service, Veterans' Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA.
| | - Kusum K Kharbanda
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA.
- Research Service, Veterans' Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA.
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Role of ghrelin isoforms in the mitigation of hepatic inflammation, mitochondrial dysfunction, and endoplasmic reticulum stress after bariatric surgery in rats. Int J Obes (Lond) 2019; 44:475-487. [PMID: 31324878 DOI: 10.1038/s41366-019-0420-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/14/2019] [Accepted: 06/09/2019] [Indexed: 01/12/2023]
Abstract
BACKGROUND/OBJECTIVES Bariatric surgery improves nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH), but the underlying mechanisms remain elusive. We evaluated the potential role of ghrelin isoforms in the amelioration of hepatic inflammation after sleeve gastrectomy and Roux-en-Y gastric bypass (RYGB). SUBJECTS/METHODS Plasma ghrelin isoforms were measured in male Wistar rats (n = 129) subjected to surgical (sham operation, sleeve gastrectomy, or RYGB) or dietary interventions [fed ad libitum a normal (ND) or a high-fat diet (HFD) or pair-fed diet]. The effect of acylated and desacyl ghrelin on markers of inflammation, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress in primary rat hepatocytes under palmitate-induced lipotoxic conditions was assessed. RESULTS Plasma desacyl ghrelin was decreased after sleeve gastrectomy and RYGB, whereas the acylated/desacyl ghrelin ratio was augmented. Both surgeries diminished obesity-associated hepatic steatosis, CD68+- and apoptotic cells, proinflammatory JNK activation, and Crp, Tnf, and Il6 transcripts. Moreover, a postsurgical amelioration in the mitochondrial DNA content, oxidative phosphorylation (OXPHOS) complexes I and II, and ER stress markers was observed. Specifically, following bariatric surgery GRP78, spliced XBP-1, ATF4, and CHOP levels were reduced, as were phosphorylated eIF2α. Interestingly, acylated and desacyl ghrelin inhibited steatosis and inflammation of palmitate-treated hepatocytes in parallel to an upregulation of OXPHOS complexes II, III, and V, and a downregulation of ER stress transducers IRE1α, PERK, ATF6, their downstream effectors, ATF4 and CHOP, as well as chaperone GRP78. CONCLUSIONS Our data suggest that the increased relative acylated ghrelin levels after bariatric surgery might contribute to mitigate obesity-associated hepatic inflammation, mitochondrial dysfunction, and ER stress.
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Erdmann S, Derno M, Schäff C, Börner S, Kautzsch U, Kuhla B, Hammon H, Tuchscherer A, Röntgen M. Comparative analyses of estimated and calorimetrically determined energy balance in high-yielding dairy cows. J Dairy Sci 2019; 102:4002-4013. [DOI: 10.3168/jds.2018-15017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 12/19/2018] [Indexed: 11/19/2022]
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Rasineni K, Thomes PG, Kubik JL, Harris EN, Kharbanda KK, Casey CA. Chronic alcohol exposure alters circulating insulin and ghrelin levels: role of ghrelin in hepatic steatosis. Am J Physiol Gastrointest Liver Physiol 2019; 316:G453-G461. [PMID: 30702902 PMCID: PMC6483023 DOI: 10.1152/ajpgi.00334.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Fatty liver is the earliest response of the liver to excessive ethanol consumption. Central in the development of alcoholic steatosis is increased mobilization of nonesterified free fatty acids (NEFAs) to the liver from the adipose tissue. In this study, we hypothesized that ethanol-induced increase in ghrelin by impairing insulin secretion, could be responsible for the altered lipid metabolism observed in adipose and liver tissue. Male Wistar rats were fed for 5-8 wk with control or ethanol Lieber-DeCarli diet, followed by biochemical analyses in serum and liver tissues. In addition, in vitro studies were conducted on pancreatic islets isolated from experimental rats. We found that ethanol increased serum ghrelin and decreased serum insulin levels in both fed and fasting conditions. These results were corroborated by our observations of a significant accumulation of insulin in pancreatic islets of ethanol-fed rats, indicating that its secretion was impaired. Furthermore, ethanol-induced reduction in circulating insulin was associated with lower adipose weight and increased NEFA levels observed in these rats. Additionally, we found that increased concentration of serum ghrelin was due to increased synthesis and maturation in the stomach of the ethanol-fed rats. We also report that in addition to its effect on the pancreas, ghrelin can also directly act on hepatocytes via the ghrelin receptors and promote fat accumulation. In conclusion, alcohol-induced elevation of circulating ghrelin levels impairs insulin secretion. Consequently, reduced circulating insulin levels likely contribute to increased free fatty acid mobilization from adipose tissue to liver, thereby contributing to hepatic steatosis. NEW & NOTEWORTHY Our studies are the first to report that ethanol-induced increases in ghrelin contribute to impaired insulin secretion, which results in the altered lipid metabolism observed in adipose and liver tissue in the setting of alcoholic fatty liver disease.
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Affiliation(s)
- Karuna Rasineni
- 1Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska,2Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| | - Paul G. Thomes
- 1Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska,2Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| | - Jacy L. Kubik
- 1Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska,2Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| | - Edward N. Harris
- 3Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Kusum K. Kharbanda
- 1Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska,2Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| | - Carol A. Casey
- 1Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska,2Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska
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Kraft EN, Cervone DT, Dyck DJ. Ghrelin stimulates fatty acid oxidation and inhibits lipolysis in isolated muscle from male rats. Physiol Rep 2019; 7:e14028. [PMID: 30963694 PMCID: PMC6453820 DOI: 10.14814/phy2.14028] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/27/2019] [Accepted: 02/27/2019] [Indexed: 11/24/2022] Open
Abstract
Ghrelin is classically known as a central appetite-stimulating hormone but has recently been recognized to have a significant role in peripheral tissue energy metabolism. However, the direct effects of ghrelin on skeletal muscle, a major site for glucose and lipid disposal, remain understudied. We found that the two major ghrelin isoforms, acylated and unacylated ghrelin, were able to significantly increase skeletal muscle fatty acid oxidation (~20%) while incorporation of fatty acids into major lipid pools remained unchanged. The increase in fatty acid oxidation was accompanied by increases in acetyl-CoA carboxylase phosphorylation, a downstream target of AMPK. Ghrelin isoforms had no independent effect on lipolysis under unstimulated conditions, but nearly completely abolished epinephrine-stimulated lipolysis. This effect was generally, but not consistently related to a blunting in the phosphorylation of HSL activation sites, Ser660 and 563. Taken together, these findings suggest that ghrelin isoforms have a direct, acute effect on fatty acid oxidation and lipolysis.
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Affiliation(s)
- Emily N. Kraft
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Daniel T. Cervone
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - David J. Dyck
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
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Goshadrou F, Arefi Oskouie A, Eslami M, Nobakht Mothlagh Ghoochani BF. Effect of ghrelin on serum metabolites in Alzheimer's disease model rats; a metabolomics studies based on 1H-NMR technique. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2018; 21:1245-1254. [PMID: 30627368 PMCID: PMC6312673 DOI: 10.22038/ijbms.2018.30596.7373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/21/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVES Alzheimer's disease (AD) is dysfunction of the central nervous system and as a neurodegenerative disease. The objective of this work is to investigate metabolic profiling in the serum of animal models of AD compared to healthy controls and then to peruse the role of ghrelin as a therapeutic approach for the AD. MATERIALS AND METHODS Nuclear magnetic resonance (NMR) technique was used for identification of metabolites that are differentially expressed in the serum of a rat model of the AD with or without ghrelin treatment. Using multivariate statistical analysis, models were built and indicated. RESULTS There were significant differences and high predictive power between AD and ghrelin-treated groups. The area under curve (AUC) of receiver operating characteristic (ROC) curve and Q2 were 0.870 and 0.759, respectively. A biomarker panel consisting of 14 metabolites was identified to discriminate the AD from the control group. Another panel of 12 serum metabolites was used to differentiate AD models from treated models. CONCLUSION Both panels had good agreements with clinical diagnosis. Analysis of the results displayed that ghrelin improved memory and cognitive abilities. Affected pathways by ghrelin included oxidative stress, and osteoporosis pathways and vascular risk factors.
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Affiliation(s)
- Fatemeh Goshadrou
- Faculty of Paramedical Sciences, Department of Basic Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Afsaneh Arefi Oskouie
- Faculty of Paramedical Sciences, Department of Basic Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Eslami
- Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
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Bertucci JI, Blanco AM, Sánchez‐Bretaño A, Unniappan S, Canosa LF. Ghrelin and NUCB2/Nesfatin‐1 Co‐Localization With Digestive Enzymes in the Intestine of Pejerrey (
Odontesthes bonariensis
). Anat Rec (Hoboken) 2018; 302:973-982. [DOI: 10.1002/ar.24012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 07/30/2018] [Accepted: 09/11/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Juan Ignacio Bertucci
- Instituto Tecnológico de Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)‐Universidad Nacional de San Martín (UNSAM) Buenos Aires Argentina
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical SciencesWestern College of Veterinary Medicine, University of Saskatchewan Saskatoon Saskatchewan Canada
| | - Ayelén Melisa Blanco
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical SciencesWestern College of Veterinary Medicine, University of Saskatchewan Saskatoon Saskatchewan Canada
- Departamento de Fisiología (Fisiología Animal II), Facultad de BiologíaUniversidad Complutense de Madrid Madrid Spain
| | - Aida Sánchez‐Bretaño
- Department of Pharmacology and Toxicology, and Neuroscience InstituteMorehouse School of Medicine 720 Westview Drive, GA, 30310 Atlanta Georgia
| | - Suraj Unniappan
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical SciencesWestern College of Veterinary Medicine, University of Saskatchewan Saskatoon Saskatchewan Canada
| | - Luis Fabián Canosa
- Instituto Tecnológico de Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)‐Universidad Nacional de San Martín (UNSAM) Buenos Aires Argentina
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Uncoupling proteins as a therapeutic target to protect the diabetic heart. Pharmacol Res 2018; 137:11-24. [PMID: 30223086 DOI: 10.1016/j.phrs.2018.09.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 09/07/2018] [Accepted: 09/13/2018] [Indexed: 12/16/2022]
Abstract
Myocardial remodeling and dysfunction caused by accelerated oxidative damage is a widely reported phenomenon within a diabetic state. Altered myocardial substrate preference appears to be the major cause of enhanced oxidative stress-mediated cell injury within a diabetic heart. During this process, exacerbated free fatty acid flux causes an abnormal increase in mitochondrial membrane potential leading to the overproduction of free radical species and subsequent cell damage. Uncoupling proteins (UCPs) are expressed within the myocardium and can protect against free radical damage by modulating mitochondrial respiration, leading to reduced production of reactive oxygen species. Moreover, transgenic animals lacking UCPs have been shown to be more susceptible to oxidative damage and display reduced cardiac function when compared to wild type animals. This suggests that tight regulation of UCPs is necessary for normal cardiac function and in the prevention of diabetes-induced oxidative damage. This review aims to enhance our understanding of the pathophysiological mechanisms relating to the role of UCPs in a diabetic heart, and further discuss known pharmacological compounds and hormones that can protect a diabetic heart through the modulation of UCPs.
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Gortan Cappellari G, Zanetti M, Vinci P, Guarnieri G, Barazzoni R. Unacylated Ghrelin: A Novel Regulator of Muscle Intermediate Metabolism With Potential Beneficial Effects in Chronic Kidney Disease. J Ren Nutr 2018; 27:474-477. [PMID: 29056169 DOI: 10.1053/j.jrn.2017.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/02/2017] [Indexed: 11/11/2022] Open
Abstract
In patients with chronic kidney disease (CKD), malnutrition with loss of skeletal muscle mass has a negative impact on morbidity and mortality. Emerging evidence indicates that a cluster of oxidative stress, inflammation, and insulin resistance directly contributes to skeletal muscle catabolism by favoring protein breakdown over synthesis. Ghrelin is a gastric hormone discovered and initially studied in its acylated orexigenic form. More recently, a role of unacylated ghrelin (UnAG) has been described to reduce skeletal muscle mitochondrial reactive oxygen species generation, inflammation, and insulin resistance both in experimental models and in clinical studies. UnAG administration could therefore represent a potential comprehensive therapeutic approach for CKD-related metabolic and nutritional complications. Studies of UnAG administration in experimental and clinical CKD are needed to test the hypothesis that UnAG may chronically improve nutritional status and outcome in CKD patients.
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Affiliation(s)
| | - Michela Zanetti
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Pierandrea Vinci
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Gianfranco Guarnieri
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Rocco Barazzoni
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy.
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Yorulmaz H, Ozkok E, Ates G, Aksu A, Balkıs N, Tamer S. Ghrelin: Impact on Muscle Energy Metabolism in Sepsis. Int J Pept Res Ther 2018. [DOI: 10.1007/s10989-017-9610-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Dallak MA. Acylated ghrelin induces but deacylated ghrelin prevents hepatic steatosis and insulin resistance in lean rats: Effects on DAG/ PKC/JNK pathway. Biomed Pharmacother 2018; 105:299-311. [PMID: 29860222 DOI: 10.1016/j.biopha.2018.05.098] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/20/2018] [Accepted: 05/21/2018] [Indexed: 12/19/2022] Open
Abstract
This study investigated the molecular effects of acylated (AG) and unacylated ghrelin (UAG) or their combination on hepatic lipogenesis pathways and DAG/PKC/JNK signaling in the livers of lean rats fed standard diet. Male rats (n = 10) were classified as control + vehicle (saline, 200 μl), AG, UAG, and AG + UAG-treated groups. All treatments were given at final doses of 200 ng/kg of for 14 days (twice/day, S.C). Administration of AG significantly enhanced circulatory levels of AG and UAG turning the normal ratio of AG/UAG from 1:2.5 to 1:1.2. However, while UAG didn't affect circulatory levels of AG, administration of UAG alone or in combination with AG resulted in AG/UAG ratios of 1:7 and 1:3, respectively. Independent of food intake nor the development of peripheral IR, AG increased hepatic DAG, TGs and CHOL contents and induced hepatic IR. Mechanism of action include 1) upregulation of mRNA and protein levels of DGAT-2 and mtGPAT-1, SREBP-1 and SCD-1, and 2) inhibition of fatty acids (FAs) oxidation mediated by inhibition of AMPK/ PPAR-α/CPT-1 axis. Consequently, AG induced membranous translocation of PKCδ and PKCε leading to activation of JNK and significant inhibition of insulin signaling under basal and insulin stimulation as evident by decreases in the phosphorylation levels of IRS (Tyr612) and Akt (Thr318) and increased phosphorylation of IRS (Ser307). However, while UAG only activated FAs oxidation in control rats, it reversed all alterations in all measured biochemical endpoints seen in the AG-treated group, when administered in combination with AG, leading to significant decreases in hepatic fat accumulation and prevention of hepatic IR. In conclusion, while exogenous administration of AG is at high risk of developing steatohepatitis and hepatic IR, co-administration of a balanced dose of UAG reduces this risk and inhibits hepatic lipid accumulation and enhance hepatic insulin signaling.
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Affiliation(s)
- Mohammad A Dallak
- Department of Physiology, College of Medicine, King's Khalid University, Abha, 61241, Saudi Arabia.
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Martínez R, Morales C, Arenal A, Morales A, Herrera F, González V, Estrada MP. Growth Hormone Secretagogue (A233) Improves Growth and Changes the Tissue Fatty Acid Profile in Juvenile Tilapia (Oreochromis niloticus
). Lipids 2018; 53:429-436. [DOI: 10.1002/lipd.12003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 10/04/2017] [Accepted: 10/04/2017] [Indexed: 12/29/2022]
Affiliation(s)
- Rebeca Martínez
- Aquatic Biotechnology Department, Biotechnology Animal Division; CIGB; Habana Cuba
| | - Carmen Morales
- Centro de Productos Naturales; Calle 198 entre 19 y 21, Atabey, Playa, Habana Cuba
| | - Amilcar Arenal
- Department of Morpho-Physiology; University of Camagüey Ignacio Agramonte Loynaz; Km 5½, Camagüey 74650 Cuba
| | - Antonio Morales
- Aquatic Biotechnology Department, Biotechnology Animal Division; CIGB; Habana Cuba
| | - Fidel Herrera
- Aquatic Biotechnology Department, Biotechnology Animal Division; CIGB; Habana Cuba
| | - Víctor González
- Centro de Productos Naturales; Calle 198 entre 19 y 21, Atabey, Playa, Habana Cuba
| | - Mario Pablo Estrada
- Aquatic Biotechnology Department, Biotechnology Animal Division; CIGB; Habana Cuba
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Vanholder R, Pletinck A, Schepers E, Glorieux G. Biochemical and Clinical Impact of Organic Uremic Retention Solutes: A Comprehensive Update. Toxins (Basel) 2018; 10:toxins10010033. [PMID: 29316724 PMCID: PMC5793120 DOI: 10.3390/toxins10010033] [Citation(s) in RCA: 191] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 12/21/2017] [Accepted: 12/23/2017] [Indexed: 02/07/2023] Open
Abstract
In this narrative review, the biological/biochemical impact (toxicity) of a large array of known individual uremic retention solutes and groups of solutes is summarized. We classified these compounds along their physico-chemical characteristics as small water-soluble compounds or groups, protein bound compounds and middle molecules. All but one solute (glomerulopressin) affected at least one mechanism with the potential to contribute to the uremic syndrome. In general, several mechanisms were influenced for each individual solute or group of solutes, with some impacting up to 7 different biological systems of the 11 considered. The inflammatory, cardio-vascular and fibrogenic systems were those most frequently affected and they are one by one major actors in the high morbidity and mortality of CKD but also the mechanisms that have most frequently been studied. A scoring system was built with the intention to classify the reviewed compounds according to the experimental evidence of their toxicity (number of systems affected) and overall experimental and clinical evidence. Among the highest globally scoring solutes were 3 small water-soluble compounds [asymmetric dimethylarginine (ADMA); trimethylamine-N-oxide (TMAO); uric acid], 6 protein bound compounds or groups of protein bound compounds [advanced glycation end products (AGEs); p-cresyl sulfate; indoxyl sulfate; indole acetic acid; the kynurenines; phenyl acetic acid;] and 3 middle molecules [β2-microglobulin; ghrelin; parathyroid hormone). In general, more experimental data were provided for the protein bound molecules but for almost half of them clinical evidence was missing in spite of robust experimental data. The picture emanating is one of a complex disorder, where multiple factors contribute to a multisystem complication profile, so that it seems of not much use to pursue a decrease of concentration of a single compound.
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Affiliation(s)
- Raymond Vanholder
- Nephrology Section, Department of Internal Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium.
| | - Anneleen Pletinck
- Nephrology Section, Department of Internal Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium.
| | - Eva Schepers
- Nephrology Section, Department of Internal Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium.
| | - Griet Glorieux
- Nephrology Section, Department of Internal Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium.
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Auclair N, Melbouci L, St-Pierre D, Levy E. Gastrointestinal factors regulating lipid droplet formation in the intestine. Exp Cell Res 2018; 363:1-14. [PMID: 29305172 DOI: 10.1016/j.yexcr.2017.12.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/28/2017] [Accepted: 12/29/2017] [Indexed: 12/22/2022]
Abstract
Cytoplasmic lipid droplets (CLD) are considered as neutral lipid reservoirs, which protect cells from lipotoxicity. It became clear that these fascinating dynamic organelles play a role not only in energy storage and metabolism, but also in cellular lipid and protein handling, inter-organelle communication, and signaling among diverse functions. Their dysregulation is associated with multiple disorders, including obesity, liver steatosis and cardiovascular diseases. The central aim of this review is to highlight the link between intra-enterocyte CLD dynamics and the formation of chylomicrons, the main intestinal dietary lipid vehicle, after overviewing the morphology, molecular composition, biogenesis and functions of CLD.
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Affiliation(s)
- N Auclair
- Research Centre, CHU Sainte-Justine and Department of Montreal, Quebec, Canada H3T 1C5; Nutrition, Université de Montréal, Montreal, Quebec, Canada H3T 1C5
| | - L Melbouci
- Research Centre, CHU Sainte-Justine and Department of Montreal, Quebec, Canada H3T 1C5; Department of Sciences and Physical Activities, UQAM, Quebec, Canada H2X 1Y4
| | - D St-Pierre
- Research Centre, CHU Sainte-Justine and Department of Montreal, Quebec, Canada H3T 1C5; Department of Sciences and Physical Activities, UQAM, Quebec, Canada H2X 1Y4
| | - E Levy
- Research Centre, CHU Sainte-Justine and Department of Montreal, Quebec, Canada H3T 1C5; Nutrition, Université de Montréal, Montreal, Quebec, Canada H3T 1C5; Institute of Nutrition and Functional Foods (INAF), Université Laval, Quebec, Quebec, Canada G1V 0A6.
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Barazzoni R, Gortan Cappellari G, Palus S, Vinci P, Ruozi G, Zanetti M, Semolic A, Ebner N, von Haehling S, Sinagra G, Giacca M, Springer J. Acylated ghrelin treatment normalizes skeletal muscle mitochondrial oxidative capacity and AKT phosphorylation in rat chronic heart failure. J Cachexia Sarcopenia Muscle 2017; 8:991-998. [PMID: 29098797 PMCID: PMC5700435 DOI: 10.1002/jcsm.12254] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 10/02/2017] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Chronic heart failure (CHF) is associated with skeletal muscle abnormalities contributing to exercise intolerance, muscle loss, and negative impact on patient prognosis. A primary role has been proposed for mitochondrial dysfunction, which may be induced by systemic and tissue inflammation and further contribute to low insulin signalling. The acylated form of the gastric hormone ghrelin (AG) may improve mitochondrial oxidative capacity and insulin signalling in both healthy and diseased rodent models. METHODS We investigated the impact of AG continuous subcutaneous administration (AG) by osmotic minipump (50 nmol/kg/day for 28 days) compared with placebo (P) on skeletal muscle mitochondrial enzyme activities, mitochondrial biogenesis regulators transcriptional expression and insulin signalling in a rodent post-myocardial infarction CHF model. RESULTS No statistically significant differences (NS) were observed among the three group in cumulative food intake. Compared with sham-operated, P had low mitochondrial enzyme activities, mitochondrial biogenesis regulators transcripts, and insulin signalling activation at AKT level (P < 0.05), associated with activating nuclear translocation of pro-inflammatory transcription factor nuclear factor-κB. AG completely normalized all alterations (P < 0.05 vs P, P = NS vs sham-operated). Direct AG activities were strongly supported by in vitro C2C12 myotubes experiments showing AG-dependent stimulation of mitochondrial enzyme activities. No changes in mitochondrial parameters and insulin signalling were observed in the liver in any group. CONCLUSIONS Sustained peripheral AG treatment with preserved food intake normalizes a CHF-induced tissue-specific cluster of skeletal muscle mitochondrial dysfunction, pro-inflammatory changes, and reduced insulin signalling. AG is therefore a potential treatment for CHF-associated muscle catabolic alterations, with potential positive impact on patient outcome.
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Affiliation(s)
- Rocco Barazzoni
- Internal Medicine, Department of Medical, Surgical and Health Sciences-University of Trieste, Trieste, Italy.,Azienda Sanitaria Universitaria Integrata di Trieste (ASUITS), Trieste, Italy
| | - Gianluca Gortan Cappellari
- Internal Medicine, Department of Medical, Surgical and Health Sciences-University of Trieste, Trieste, Italy.,Azienda Sanitaria Universitaria Integrata di Trieste (ASUITS), Trieste, Italy
| | - Sandra Palus
- Department of Cardiology & Pneumology, University Medical Center Göttingen (UMG), Göttingen, Germany
| | - Pierandrea Vinci
- Internal Medicine, Department of Medical, Surgical and Health Sciences-University of Trieste, Trieste, Italy.,Azienda Sanitaria Universitaria Integrata di Trieste (ASUITS), Trieste, Italy
| | - Giulia Ruozi
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Michela Zanetti
- Internal Medicine, Department of Medical, Surgical and Health Sciences-University of Trieste, Trieste, Italy.,Azienda Sanitaria Universitaria Integrata di Trieste (ASUITS), Trieste, Italy
| | - Annamaria Semolic
- Internal Medicine, Department of Medical, Surgical and Health Sciences-University of Trieste, Trieste, Italy.,Azienda Sanitaria Universitaria Integrata di Trieste (ASUITS), Trieste, Italy
| | - Nicole Ebner
- Department of Cardiology & Pneumology, University Medical Center Göttingen (UMG), Göttingen, Germany
| | - Stephan von Haehling
- Department of Cardiology & Pneumology, University Medical Center Göttingen (UMG), Göttingen, Germany
| | - Gianfranco Sinagra
- Azienda Sanitaria Universitaria Integrata di Trieste (ASUITS), Trieste, Italy.,Cardiology Division, Department of Medical, Surgical and Health Sciences-University of Trieste, Trieste, Italy
| | - Mauro Giacca
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Jochen Springer
- Department of Cardiology & Pneumology, University Medical Center Göttingen (UMG), Göttingen, Germany
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Gortan Cappellari G, Semolic A, Ruozi G, Vinci P, Guarnieri G, Bortolotti F, Barbetta D, Zanetti M, Giacca M, Barazzoni R. Unacylated ghrelin normalizes skeletal muscle oxidative stress and prevents muscle catabolism by enhancing tissue mitophagy in experimental chronic kidney disease. FASEB J 2017; 31:5159-5171. [PMID: 28778977 DOI: 10.1096/fj.201700126r] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 07/17/2017] [Indexed: 12/18/2022]
Abstract
Unacylated ghrelin (UnAG) may lower skeletal muscle oxidative stress, inflammation, and insulin resistance in lean and obese rodents. UnAG-induced autophagy activation may contribute to these effects, likely involving removal of dysfunctional mitochondria (mitophagy) and redox state maintenance. In chronic kidney disease (CKD) oxidative stress, inflammation and insulin resistance may negatively influence patient outcome by worsening nutritional state through muscle mass loss. Here we show in a 5/6 nephrectomy (Nx) CKD rat model that 4 d s.c. UnAG administration (200 µg twice a day) normalizes CKD-induced loss of gastrocnemius muscle mass and a cluster of high tissue mitochondrial reactive oxygen species generation, high proinflammatory cytokines, and low insulin signaling activation. Consistent with these results, human uremic serum enhanced mitochondrial reactive oxygen species generation and lowered insulin signaling activation in C2C12 myotubes while concomitant UnAG incubation completely prevented these effects. Importantly, UnAG enhanced muscle mitophagy in vivo and silencing RNA-mediated autophagy protein 5 silencing blocked UnAG activities in myotubes. UnAG therefore normalizes CKD-induced skeletal muscle oxidative stress, inflammation, and low insulin signaling as well as muscle loss. UnAG effects are mediated by autophagy activation at the mitochondrial level. UnAG administration and mitophagy activation are novel potential therapeutic strategies for skeletal muscle metabolic abnormalities and their negative clinical impact in CKD.-Gortan Cappellari, G., Semolic, A., Ruozi, G., Vinci, P., Guarnieri, G., Bortolotti, F., Barbetta, D., Zanetti, M., Giacca, M., Barazzoni, R. Unacylated ghrelin normalizes skeletal muscle oxidative stress and prevents muscle catabolism by enhancing tissue mitophagy in experimental chronic kidney disease.
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Affiliation(s)
| | - Annamaria Semolic
- Department of Medical, Surgical, and Health Sciences, University of Trieste, Trieste, Italy
| | - Giulia Ruozi
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Pierandrea Vinci
- Department of Medical, Surgical, and Health Sciences, University of Trieste, Trieste, Italy
| | - Gianfranco Guarnieri
- Department of Medical, Surgical, and Health Sciences, University of Trieste, Trieste, Italy
| | - Francesca Bortolotti
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Michela Zanetti
- Department of Medical, Surgical, and Health Sciences, University of Trieste, Trieste, Italy
| | - Mauro Giacca
- Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Rocco Barazzoni
- Department of Medical, Surgical, and Health Sciences, University of Trieste, Trieste, Italy;
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48
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Guillory B, Chen JA, Patel S, Luo J, Splenser A, Mody A, Ding M, Baghaie S, Anderson B, Iankova B, Halder T, Hernandez Y, Garcia JM. Deletion of ghrelin prevents aging-associated obesity and muscle dysfunction without affecting longevity. Aging Cell 2017; 16:859-869. [PMID: 28585250 PMCID: PMC5506439 DOI: 10.1111/acel.12618] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2017] [Indexed: 01/06/2023] Open
Abstract
During aging, decreases in energy expenditure and locomotor activity lead to body weight and fat gain. Aging is also associated with decreases in muscle strength and endurance leading to functional decline. Here, we show that lifelong deletion of ghrelin prevents development of obesity associated with aging by modulating food intake and energy expenditure. Ghrelin deletion also attenuated the decrease in phosphorylated adenosine monophosphate‐activated protein kinase (pAMPK) and downstream mediators in muscle, and increased the number of type IIa (fatigue resistant, oxidative) muscle fibers, preventing the decline in muscle strength and endurance seen with aging. Longevity was not affected by ghrelin deletion. Treatment of old mice with pharmacologic doses of ghrelin increased food intake, body weight, and muscle strength in both ghrelin wild‐type and knockout mice. These findings highlight the relevance of ghrelin during aging and identify a novel AMPK‐dependent mechanism for ghrelin action in muscle.
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Affiliation(s)
- Bobby Guillory
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
| | - Ji-an Chen
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
- Department of Health Education; College of Preventive Medicine; Third Military Medical University; Chongqing 400038 China
| | - Shivam Patel
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
| | - Jiaohua Luo
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
- Department of Environmental Hygiene; College of Preventive Medicine; Third Military Medical University; Chongqing 400038 China
| | - Andres Splenser
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
| | - Avni Mody
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
| | - Michael Ding
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
- GRECC; VA Puget Sound Health Care System and University of Washington; Seattle WA USA
| | - Shiva Baghaie
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
| | - Barbara Anderson
- GRECC; VA Puget Sound Health Care System and University of Washington; Seattle WA USA
| | - Blaga Iankova
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
| | - Tripti Halder
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
| | - Yamileth Hernandez
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
| | - Jose M. Garcia
- Division of Diabetes; Endocrinology and Metabolism; MCL; Center for Translational Research on Inflammatory Diseases; Michael E DeBakey Veterans Affairs Medical Center and Baylor College of Medicine; Houston TX USA
- GRECC; VA Puget Sound Health Care System and University of Washington; Seattle WA USA
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49
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López M, Tena-Sempere M. Estradiol effects on hypothalamic AMPK and BAT thermogenesis: A gateway for obesity treatment? Pharmacol Ther 2017; 178:109-122. [PMID: 28351720 DOI: 10.1016/j.pharmthera.2017.03.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 03/21/2017] [Indexed: 12/24/2022]
Abstract
In addition to their prominent roles in the control of reproduction, estrogens are important modulators of energy balance, as evident in conditions of deficiency of estrogens, which are characterized by increased feeding and decreased energy expenditure, leading to obesity. AMP-activated protein kinase (AMPK) is a ubiquitous cellular energy gauge that is activated under conditions of low energy, increasing energy production and reducing energy wasting. Centrally, the AMPK pathway is a canonical route regulating energy homeostasis, by integrating peripheral signals, such as hormones and metabolites, with neuronal networks. As a result of those actions, hypothalamic AMPK modulates feeding, as well as brown adipose tissue (BAT) thermogenesis and browning of white adipose tissue (WAT). Here, we will review the central actions of estrogens on energy balance, with particular focus on hypothalamic AMPK. The relevance of this interaction is noteworthy, because some agents with known actions on metabolic homeostasis, such as nicotine, metformin, liraglutide, olanzapine and also natural molecules, such as resveratrol and flavonoids, exert their actions by modulating AMPK. This evidence highlights the possibility that hypothalamic AMPK might be a potential target for the treatment of obesity.
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Affiliation(s)
- Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria (IDIS), 15782 Santiago de Compostela, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos II, Spain.
| | - Manuel Tena-Sempere
- CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos II, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Spain; Instituto Maimónides de Investigación Biomédica (IMIBIC)/Hospital Reina Sofía, 14004 Córdoba, Spain; FiDiPro Program, Department of Physiology, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland.
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50
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Miller DW, Prosser Z, Chee EYW, Hansen CF, Dunshea FR, Mullan BP, Pluske JR. Dietary stimulation of the endogenous somatotropic axis in weaner and grower-finisher pigs using medium chain triglycerides and cysteamine hydrochloride. J Anim Sci Biotechnol 2016; 7:61. [PMID: 27777763 PMCID: PMC5069931 DOI: 10.1186/s40104-016-0121-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 10/01/2016] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Three experiments were conducted to examine the overall hypothesis that addition of medium chain triglycerides (MCT) and cysteamine hydrochloride (CSH) into the diets of young and growing pigs would stimulate the endogenous somatotropic axis to improve growth and performance. RESULTS In Experiment 1, weaner pigs were given either a 5 d dietary supplement of 5 % MCT (n = 8) or a control diet (n = 8). MCT increased the plasma concentration of growth hormone (GH; P < 0.05) and the GH secretagogue, ghrelin (P < 0.05). Additionally, the MCT treatment reduced scouring (P < 0.05), maintained villous height in the small intestine (P < 0.05) and stabilised daily weight gain (P < 0.05), compared to the controls. Experiment 2 compared the effects of 4 levels (0, 1, 3 and 6 % v/v) of MCT supplementation in grower-finisher male pigs, of approximately 35 kg live weight (n = 15 per treatment). Blood samples taken after 7 wk of treatment showed that the MCT supplementation increased circulating ghrelin (P < 0.001), GH (P < 0.01) and insulin (P < 0.05) concentrations in a dose-dependent manner. Daily weight gain, feed intake and feed conversion ratio were not affected by the MCT diets. In Experiment 3, 64 female pigs of approximately 60 kg live weight were allocated to one of three dietary treatments: control (n = 20); 6 % MCT (n = 21); and 70 mg/kg CSH (n = 21). After 3 wk of supplementation, the MCT treated pigs had a higher plasma concentration of ghrelin compared to the control and CSH pigs (P < 0.05). Plasma concentrations of GH and weight were not affected by any of the dietary treatments. CONCLUSIONS Evidence is provided in Experiment 1 to support the use of dietary MCT supplements, perhaps acting via stimulation of somatotropic endocrine pathways, to minimise weaning-associated disorders such as slowing of growth and diarrhoea. In Experiments 2 and 3, although there was no effect on weight gain or feed conversion ratio in either experiment, MCT and CSH increased endocrine components of the somatotropic axis.
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Affiliation(s)
- David W. Miller
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia
| | - Zoe Prosser
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia
| | - Edward Y. W. Chee
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia
| | - Christian F. Hansen
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Groennegaardsvej 2, 1870 Frederiksberg C, Denmark
| | - Frank R. Dunshea
- Melbourne School of Land and Environment, University of Melbourne, Parkville, VIC 3051 Australia
| | - Bruce P. Mullan
- Department of Agriculture and Food Western Australia, Bentley Delivery Center, Locked Bag 4, Bentley, WA 6983 Australia
| | - John R. Pluske
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia
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