1
|
Perivascular Adipose Tissue Inflammation: The Anti-Inflammatory Role of Ghrelin in Atherosclerosis Progression. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12073307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Perivascular adipose tissue (PVAT) and its adipokines engage in bidirectional crosstalk with the vascular wall. Atherosclerosis disrupts this interaction through inflammation, rupture-prone plaques, and subsequent thrombosis. The cardioprotective effects of ghrelin are in contradiction to its adipogenic properties. The concurrent research of anti-/pro-atherogenic mechanisms of ghrelin and PVAT-derived adipokines provides a better understanding of atherosclerosis progression in metabolic disorders. In-depth coverage of the characteristic features of PVAT concerning vascular dysfunction, with a survey of ghrelin-induced anti-inflammatory effects on adipose tissue macrophage infiltration and the inhibitory activity of ghrelin on the proinflammatory adipokine secretion, show that the impact of ghrelin on the endothelial function should be studied in relation to PVAT.
Collapse
|
2
|
Effect of Bacterial Infection on Ghrelin Receptor Regulation in Periodontal Cells and Tissues. Int J Mol Sci 2022; 23:ijms23063039. [PMID: 35328456 PMCID: PMC8950409 DOI: 10.3390/ijms23063039] [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: 01/31/2022] [Revised: 03/03/2022] [Accepted: 03/09/2022] [Indexed: 12/04/2022] Open
Abstract
The effect of bacterial infection on the expression of growth hormone secretagogue receptor (GHS-R) was investigated in periodontal cells and tissues, and the actions of ghrelin were evaluated. GHS-R was assessed in periodontal tissues of rats with and without periodontitis. Human gingival fibroblasts (HGFs) were exposed to Fusobacterium nucleatum in the presence and absence of ghrelin. GHS-R expression was determined by real-time PCR and immunocytochemistry. Furthermore, wound healing, cell viability, proliferation, and migration were evaluated. GHS-R expression was significantly higher at periodontitis sites as compared to healthy sites in rat tissues. F. nucleatum significantly increased the GHS-R expression and protein level in HGFs. Moreover, ghrelin significantly abrogated the stimulatory effects of F. nucleatum on CCL2 and IL-6 expressions in HGFs and did not affect cell viability and proliferation significantly. Ghrelin stimulated while F. nucleatum decreased wound closure, probably due to reduced cell migration. Our results show original evidence that bacterial infection upregulates GHS-R in rat periodontal tissues and HGFs. Moreover, our study shows that ghrelin inhibited the proinflammatory actions of F. nucleatum on HGFs without interfering with cell viability and proliferation, suggesting that ghrelin and its receptor may act as a protective molecule during bacterial infection on periodontal cells.
Collapse
|
3
|
Regional Differences in the Ghrelin-Growth Hormone Secretagogue Receptor Signalling System in Human Heart Disease. CJC Open 2020; 3:182-194. [PMID: 33644732 PMCID: PMC7893201 DOI: 10.1016/j.cjco.2020.10.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 10/27/2020] [Indexed: 12/20/2022] Open
Abstract
Background The hormone ghrelin and its receptor, the growth hormone secretagogue receptor (GHSR) are expressed in myocardium. GHSR binding activates signalling pathways coupled to cardiomyocyte survival and contractility. These properties have made the ghrelin-GHSR axis a candidate for a biomarker of cardiac function. The dynamics of ghrelin-GHSR are altered significantly in late stages of heart failure (HF) and cardiomyopathy, when left ventricular (LV) function is failing. We examined the relationship of GHSR with ghrelin in cardiac tissue from patients with valvular disease with no detectable changes in LV function. Methods Biopsy samples from the left ventricle and left atrium were obtained from 25 patients with valvular disease (of whom 13 also had coronary artery disease) and preserved LV ejection fraction, and compared to control samples obtained via autopsy. Using quantitative confocal fluorescence microscopy, levels of GHSR were determined using [Dpr3(n-octanoyl),Lys19(sulfo-Cy5)]ghrelin(1-19), and immunofluorescence determined ghrelin, the heart failure marker natriuretic peptide type-B (BNP), and contractility marker sarcoplasmic reticulum ATPase pump (SERCA2a). Results A positive correlation between GHSR and ghrelin was apparent in only diseased tissue. Ghrelin and BNP significantly correlated in the left ventricle and strongly colocalized to the same intracellular compartment in diseased and control tissue. GHSR, ghrelin, and BNP all strongly and significantly correlated with SERCA2a in the left ventricle of diseased tissue only. Conclusions Our results suggest that the dynamics of the myocardial ghrelin-GHSR axis is altered in cardiovascular disease in the absence of measurable changes in heart function, and might accompany a regional shift in endocrine programming.
Collapse
|
4
|
Gupta S, Mitra A. Heal the heart through gut (hormone) ghrelin: a potential player to combat heart failure. Heart Fail Rev 2020; 26:417-435. [PMID: 33025414 DOI: 10.1007/s10741-020-10032-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/21/2020] [Indexed: 12/17/2022]
Abstract
Ghrelin, a small peptide hormone (28 aa), secreted mainly by X/A-like cells of gastric mucosa, is also locally produced in cardiomyocytes. Being an orexigenic factor (appetite stimulant), it promotes release of growth hormone (GH) and exerts diverse physiological functions, viz. regulation of energy balance, glucose, and/or fat metabolism for body weight maintenance. Interestingly, administration of exogenous ghrelin significantly improves cardiac functions in CVD patients as well as experimental animal models of heart failure. Ghrelin ameliorates pathophysiological condition of the heart in myocardial infarction, cardiac hypertrophy, fibrosis, cachexia, and ischemia reperfusion injury. This peptide also exerts significant impact at the level of vasculature leading to lowering high blood pressure and reversal of endothelial dysfunction and atherosclerosis. However, the molecular mechanism of actions elucidating the healing effects of ghrelin on the cardiovascular system is still a matter of conjecture. Some experimental data indicate its beneficial effects via complex cellular cross talks between autonomic nervous system and cardiovascular cells, some other suggest more direct receptor-mediated molecular actions via autophagy or ionotropic regulation and interfering with apoptotic and inflammatory pathways of cardiomyocytes and vascular endothelial cells. Here, in this review, we summarise available recent data to encourage more research to find the missing links of unknown ghrelin receptor-mediated pathways as we see ghrelin as a future novel therapy in cardiovascular protection.
Collapse
Affiliation(s)
- Shreyasi Gupta
- Department of Zoology, Triveni Devi Bhalotia College, Raniganj, Paschim Bardhaman, 713347, India
| | - Arkadeep Mitra
- Department of Zoology, City College , 102/1, Raja Rammohan Sarani, Kolkata, 700009, India.
| |
Collapse
|
5
|
Exogenous Ghrelin Increases Plasma Insulin Level in Diabetic Rats. Biomolecules 2020; 10:biom10040633. [PMID: 32325912 PMCID: PMC7226305 DOI: 10.3390/biom10040633] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/09/2020] [Accepted: 04/15/2020] [Indexed: 12/13/2022] Open
Abstract
Ghrelin, a 28-amino acid peptide, is a strong growth hormone secretagogue and a regulator of food intake. In addition, ghrelin is thought to play a role in insulin secretion and in glucose homeostasis. A lot of contradictory data have been reported in the literature regarding the co-localization of ghrelin with other hormones in the islet of Langerhans, its role in insulin secretion and attenuation of type 2 diabetes mellitus. In this study, we investigate the effect of chronic ghrelin treatment on glucose, body weight and insulin level in normal and streptozotocin-induced diabetic male Wistar rats. We have also examined the distribution pattern and co-localization of ghrelin with insulin in pancreatic islet cells using immunohistochemistry and immune-electron microscopy and the ability of ghrelin to stimulate insulin release from the CRL11065 beta cell line. Control, non-diabetic groups received intraperitoneal injection of normal saline, while treated groups received intraperitoneal injection of 5 µg/kg body weight of ghrelin (amino acid chain 24–51) on a daily basis for a duration of four weeks. Our results show that the administration of ghrelin increases the number of insulin-secreting beta cells and serum insulin level in both normal and diabetic rats. We also demonstrated that ghrelin co-localizes with insulin in pancreatic islet cells and that the pattern of ghrelin distribution is altered after the onset of diabetes. Moreover, ghrelin at a dose of 10−6 M and 10−12 M increased insulin release from the CRL11065 beta cell line. In summary, ghrelin co-localizes with insulin in the secretory granules of pancreatic beta cells and enhances insulin production.
Collapse
|
6
|
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.
Collapse
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.
| |
Collapse
|
7
|
Serrenho D, Santos SD, Carvalho AL. The Role of Ghrelin in Regulating Synaptic Function and Plasticity of Feeding-Associated Circuits. Front Cell Neurosci 2019; 13:205. [PMID: 31191250 PMCID: PMC6546032 DOI: 10.3389/fncel.2019.00205] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 04/24/2019] [Indexed: 12/21/2022] Open
Abstract
Synaptic plasticity of the neuronal circuits associated with feeding behavior is regulated by peripheral signals as a response to changes in the energy status of the body. These signals include glucose, free fatty acids, leptin and ghrelin and are released into circulation, being able to reach the brain. Ghrelin, a small peptide released from the stomach, is an orexigenic hormone produced in peripheral organs, and its action regulates food intake, body weight and glucose homeostasis. Behavioral studies show that ghrelin is implicated in the regulation of both hedonic and homeostatic feeding and of cognition. Ghrelin-induced synaptic plasticity has been described in neuronal circuits associated with these behaviors. In this review, we discuss the neuromodulatory mechanisms induced by ghrelin in regulating synaptic plasticity in three main neuronal circuits previously associated with feeding behaviors, namely hypothalamic (homeostatic feeding), ventral tegmental (hedonic and motivational feeding) and hippocampal (cognitive) circuits. Given the central role of ghrelin in regulating feeding behaviors, and the altered ghrelin levels associated with metabolic disorders such as obesity and anorexia, it is of paramount relevance to understand the effects of ghrelin on synaptic plasticity of neuronal circuits associated with feeding behaviors.
Collapse
Affiliation(s)
- Débora Serrenho
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal.,PhD Program in Experimental Biology and Biomedicine (PDBEB), University of Coimbra, Coimbra, Portugal
| | - Sandra D Santos
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal
| | - Ana Luísa Carvalho
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| |
Collapse
|
8
|
Kitazawa T, Kaiya H. Regulation of Gastrointestinal Motility by Motilin and Ghrelin in Vertebrates. Front Endocrinol (Lausanne) 2019; 10:278. [PMID: 31156548 PMCID: PMC6533539 DOI: 10.3389/fendo.2019.00278] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/16/2019] [Indexed: 12/14/2022] Open
Abstract
The energy balance of vertebrates is regulated by the difference in energy input and energy expenditure. Generally, most vertebrates obtain their energy from nutrients of foods through the gastrointestinal (GI) tract. Therefore, food intake and following food digestion, including motility of the GI tract, secretion and absorption, are crucial physiological events for energy homeostasis. GI motility changes depending on feeding, and GI motility is divided into fasting (interdigestive) and postprandial (digestive) contraction patterns. GI motility is controlled by contractility of smooth muscles of the GI tract, extrinsic and intrinsic neurons (motor and sensory) and some hormones. In mammals, ghrelin (GHRL) and motilin (MLN) stimulate appetite and GI motility and contribute to the regulation of energy homeostasis. GHRL and MLN are produced in the mucosal layer of the stomach and upper small intestine, respectively. GHRL is a multifunctional peptide and is involved in glucose metabolism, endocrine/exocrine functions and cardiovascular and reproductive functions, in addition to feeding and GI motility in mammals. On the other hand, the action of MLN is restricted and species such as rodentia, including mice and rats, lack MLN peptide and its receptor. From a phylogenetic point of view, GHRL and its receptor GHS-R1a have been identified in various vertebrates, and their structural features and various physiological functions have been revealed. On the other hand, MLN or MLN-like peptide (MLN-LP) and its receptors have been found only in some fish, birds and mammals. Here, we review the actions of GHRL and MLN with a focus on contractility of the GI tract of species from fish to mammals.
Collapse
Affiliation(s)
- Takio Kitazawa
- Comparative Animal Pharmacology, Department of Veterinary Science, Rakuno Gakuen University, Ebetsu, Japan
- *Correspondence: Takio Kitazawa
| | - Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| |
Collapse
|
9
|
The CD36-PPARγ Pathway in Metabolic Disorders. Int J Mol Sci 2018; 19:ijms19051529. [PMID: 29883404 PMCID: PMC5983591 DOI: 10.3390/ijms19051529] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 05/08/2018] [Accepted: 05/16/2018] [Indexed: 12/21/2022] Open
Abstract
Uncovering the biological role of nuclear receptor peroxisome proliferator-activated receptors (PPARs) has greatly advanced our knowledge of the transcriptional control of glucose and energy metabolism. As such, pharmacological activation of PPARγ has emerged as an efficient approach for treating metabolic disorders with the current use of thiazolidinediones to improve insulin resistance in diabetic patients. The recent identification of growth hormone releasing peptides (GHRP) as potent inducers of PPARγ through activation of the scavenger receptor CD36 has defined a novel alternative to regulate essential aspects of lipid and energy metabolism. Recent advances on the emerging role of CD36 and GHRP hexarelin in regulating PPARγ downstream actions with benefits on atherosclerosis, hepatic cholesterol biosynthesis and fat mitochondrial biogenesis are summarized here. The response of PPARγ coactivator PGC-1 is also discussed in these effects. The identification of the GHRP-CD36-PPARγ pathway in controlling various tissue metabolic functions provides an interesting option for metabolic disorders.
Collapse
|
10
|
Rhodes L, Zollers B, Wofford JA, Heinen E. Capromorelin: a ghrelin receptor agonist and novel therapy for stimulation of appetite in dogs. Vet Med Sci 2018; 4:3-16. [PMID: 29468076 PMCID: PMC5813110 DOI: 10.1002/vms3.83] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ghrelin is a hormone, secreted from cells in the stomach, which is important in the regulation of appetite and food intake in mammals. It exerts its action by binding to a specific G-protein-coupled receptor, the growth hormone secretagogue receptor 1a (GHS-R1a) which is found in areas of the brain associated with the regulation of food intake. Ghrelin causes a release of growth hormone (GH) through binding to GHS-R1a in the hypothalamus and pituitary gland. A class of compounds known as growth hormone secretagogues, or ghrelin receptor agonists, were developed for therapeutic use in humans for the stimulation of GH in the frail elderly, and have subsequently been studied for their effects on increasing appetite and food intake, increasing body weight, building lean muscle mass, and treating cachexia. Subsequent research has shown that ghrelin has anti-inflammatory and immunomodulatory effects. This article reviews the basic physiology of ghrelin and the ghrelin receptor agonists, including the available evidence of these effects in vitro and in vivo in rodent models, humans, dogs and cats. One of these compounds, capromorelin, has been FDA-approved for the stimulation of appetite in dogs (ENTYCE ®). The data available on the safety and effectiveness of capromorelin is reviewed, along with a discussion of the potential clinical applications for ghrelin receptor agonists in both human and veterinary medicine.
Collapse
|
11
|
Development and initial characterization of a novel ghrelin receptor CRISPR/Cas9 knockout wistar rat model. Int J Obes (Lond) 2018; 43:344-354. [PMID: 29453460 PMCID: PMC6066458 DOI: 10.1038/s41366-018-0013-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/11/2017] [Accepted: 12/10/2017] [Indexed: 01/18/2023]
Abstract
Background/objectives Ghrelin, a stomach-derived hormone implicated in numerous behaviors including feeding, reward, stress, and addictive behaviors, acts through binding to the growth hormone secretagogue receptor (GHSR). Here, we present the development, verification and initial characterization of a novel GHSR knockout (KO) Wistar rat model created with CRISPR genome editing. Methods Using CRISPR/Cas9, we developed a GHSR knockout (KO) in a Wistar background. Loss of GHSR mRNA expression was histologically verified using RNAscope in wild-type WT (n = 2) and KO (n = 2) rats. We tested the effects of intraperitoneal acyl-ghrelin administration on food consumption and plasma growth hormone (GH) concentrations in WT (n = 8) and KO (n = 8) rats. We also analyzed locomotion, food consumption, and body fat composition in these animals. Body weight was monitored from early development to adulthood. Results The RNAscope analysis revealed an abundance of GHSR mRNA expression in the hypothalamus, midbrain, and hippocampus in WTs, and no observed probe binding in KOs. Ghrelin administration increased plasma GH levels (p = 0.0067) and food consumption (p = 0.0448) in WT rats but not KOs. KO rats consumed less food overall at basal conditions and weighed significantly less compared with WTs throughout development (p = 0.0001). Compared with WTs, KOs presented higher concentrations of brown adipose tissue (BAT) (p = 0.0322). Conclusions We have verified GHSR deletion in our KO model using histological, physiological, neuroendocrinological and behavioral measures. Our findings indicate that GHSR deletion in rats is not only associated with a lack of response to ghrelin, but also associated with decreases in daily food consumption and body growth, and increases in BAT. This GHSR KO Wistar rat model provides a novel tool for studying the role of the ghrelin system in obesity and in a wide range of medical and neuropsychiatric disorders.
Collapse
|
12
|
Clarifying the Ghrelin System's Ability to Regulate Feeding Behaviours Despite Enigmatic Spatial Separation of the GHSR and Its Endogenous Ligand. Int J Mol Sci 2017; 18:ijms18040859. [PMID: 28422060 PMCID: PMC5412441 DOI: 10.3390/ijms18040859] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/04/2017] [Accepted: 04/11/2017] [Indexed: 12/23/2022] Open
Abstract
Ghrelin is a hormone predominantly produced in and secreted from the stomach. Ghrelin is involved in many physiological processes including feeding, the stress response, and in modulating learning, memory and motivational processes. Ghrelin does this by binding to its receptor, the growth hormone secretagogue receptor (GHSR), a receptor found in relatively high concentrations in hypothalamic and mesolimbic brain regions. While the feeding and metabolic effects of ghrelin can be explained by the effects of this hormone on regions of the brain that have a more permeable blood brain barrier (BBB), ghrelin produced within the periphery demonstrates a limited ability to reach extrahypothalamic regions where GHSRs are expressed. Therefore, one of the most pressing unanswered questions plaguing ghrelin research is how GHSRs, distributed in brain regions protected by the BBB, are activated despite ghrelin’s predominant peripheral production and poor ability to transverse the BBB. This manuscript will describe how peripheral ghrelin activates central GHSRs to encourage feeding, and how central ghrelin synthesis and ghrelin independent activation of GHSRs may also contribute to the modulation of feeding behaviours.
Collapse
|
13
|
Ghrelin protected neonatal rat cardiomyocyte against hypoxia/reoxygenation injury by inhibiting apoptosis through Akt-mTOR signal. Mol Biol Rep 2017; 44:219-226. [PMID: 28281036 DOI: 10.1007/s11033-017-4098-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 01/02/2017] [Indexed: 12/17/2022]
Abstract
Reducing reperfusion period myocardial cell damage is efficient to reduce myocardial ischemia-reperfusion injury. Ghrelin can increase myocardial contractility, improve heart failure caused by myocardial infarction. This study aimed to investigate the protective effect of Ghrelin on myocardial hypoxia/reoxygenation (H/R) injury of neonatal rat cardiomyocytes (NRCMs) and to explore the mechanisms. We isolated the NRCMs, established myocardial H/R model, blocked growth hormone secretagogue receptor (GHSR) by siRNA technique, examined cell activity by MTT and LDH assay, detected apoptosis by Hoechst 33258 staining and flow cytometry and determined the expression levels of apoptosis related proteins and signaling pathway proteins by western blot. We found that Ghrelin can significantly improve cell activity and decrease apoptosis after H/R, however this effect was abolished by GHSR-siRNA. In addition, we found that Ghrelin can significantly increase the expression of Bcl-2 but inhibit the level of Bax and caspase-3. Further mechanism study found that the phosphorylation level of signaling pathway protein Akt and mTOR in Ghrelin treated group were significantly higher than that in other groups. In conclusion, Ghrelin can reduce the H/R damage on NRCMs and inhibit the apoptosis by activating Akt-mTOR signaling pathway.
Collapse
|
14
|
Vestergaard ET, Jessen N, Møller N, Jørgensen JOL. Acyl Ghrelin Induces Insulin Resistance Independently of GH, Cortisol, and Free Fatty Acids. Sci Rep 2017; 7:42706. [PMID: 28198428 PMCID: PMC5309923 DOI: 10.1038/srep42706] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/17/2017] [Indexed: 02/05/2023] Open
Abstract
Ghrelin produced in the gut stimulates GH and ACTH secretion from the pituitary and also stimulates appetite and gastric emptying. We have shown that ghrelin also induces insulin resistance via GH-independent mechanisms, but it is unknown if this effect depends on ambient fatty acid (FFA) levels. We investigated the impact of ghrelin and pharmacological antilipolysis (acipimox) on insulin sensitivity and substrate metabolism in 8 adult hypopituitary patients on stable replacement with GH and hydrocortisone using a 2 × 2 factorial design: Ghrelin infusion, saline infusion, ghrelin plus short-term acipimox, and acipimox alone. Peripheral and hepatic insulin sensitivity was determined with a hyperinsulinemic euglycemic clamp in combination with a glucose tracer infusion. Insulin signaling was assayed in muscle biopsies. Peripheral insulin sensitivity was reduced by ghrelin independently of ambient FFA concentrations and was increased by acipimox independently of ghrelin. Hepatic insulin sensitivity was increased by acipimox. Insulin signaling pathways in skeletal muscle were not consistently regulated by ghrelin. Our data demonstrate that ghrelin induces peripheral insulin resistance independently of GH, cortisol, and FFA. The molecular mechanisms remain elusive, but we speculate that ghrelin is a hitherto unrecognized direct regulator of substrate metabolism. We also suggest that acipimox per se improves hepatic insulin sensitivity.
Collapse
Affiliation(s)
- Esben T Vestergaard
- Medical Research Laboratory, Aarhus University, Nørrebrogade 44 building 3B, 8000 Aarhus C, Denmark.,Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Nørrebrogade 44 building 2A, 8000 Aarhus C, Denmark.,Department of Pediatrics, Randers Regional Hospital, Randers 8930 Denmark
| | - Niels Jessen
- Medical Research Laboratory, Aarhus University, Nørrebrogade 44 building 3B, 8000 Aarhus C, Denmark.,Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Nørrebrogade 44 building 2A, 8000 Aarhus C, Denmark.,Research Laboratory for Biochemical Pathology, Department of Clinical Medicine, Aarhus University Hospital, Nørrebrogade 44 building 3A, 8000 Aarhus C, Denmark
| | - Niels Møller
- Medical Research Laboratory, Aarhus University, Nørrebrogade 44 building 3B, 8000 Aarhus C, Denmark.,Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Nørrebrogade 44 building 2A, 8000 Aarhus C, Denmark
| | - Jens Otto Lunde Jørgensen
- Medical Research Laboratory, Aarhus University, Nørrebrogade 44 building 3B, 8000 Aarhus C, Denmark.,Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Nørrebrogade 44 building 2A, 8000 Aarhus C, Denmark
| |
Collapse
|
15
|
González-Domínguez MI, Lazo-de-la-Vega-Monroy ML, Zaina S, Sabanero M, Daza-Benítez L, Malacara JM, Barbosa-Sabanero G. Association of cord blood des-acyl ghrelin with birth weight, and placental GHS-R1 receptor expression in SGA, AGA, and LGA newborns. Endocrine 2016; 53:182-91. [PMID: 26754660 DOI: 10.1007/s12020-015-0833-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 12/14/2015] [Indexed: 11/29/2022]
Abstract
Although ghrelin in cord blood has been associated to birth weight, its role in fetal and postnatal growth has not been elucidated. The aim of this study was to analyze total ghrelin, acyl ghrelin (AG), and des-acyl ghrelin (DAG) in cord blood of newborns with idiopathic birth weight alterations, and to evaluate protein expression of placental GHS-R1, in order to investigate their correlation with birth weight and placental weight. We performed a cross-sectional comparative study in umbilical cord blood and placentas from healthy mothers of SGA, AGA, and LGA (small, adequate and large for gestational age) term newborns (n = 20 per group). Cord blood total ghrelin, AG, and DAG were measured by ELISA, and placental GHS-R1 expression was evaluated by Western blot. Cord blood DAG was higher in SGA compared to AGA newborns (902.1 ± 109.1 and 597.4 ± 58.2 pg/ml, respectively, p = 0.01) while LGA and AGA showed similar values (627.2 ± 76.4 pg/ml for LGA, p = 0.80). DAG negatively correlated with birthweight (r = -0.31, p = 0.02) and placental weight (r = -0.33, p = 0.02). No differences in AG or total ghrelin were found. GHS-R1 protein in placenta was not differentially expressed among SGA, AGA, and LGA. Our results suggest a role of DAG in intrauterine growth. Further studies are needed in order to elucidate the mechanisms by which DAG participates in fetal growth.
Collapse
Affiliation(s)
- Martha I González-Domínguez
- Medical Sciences Department, Health Sciences Division, University of Guanajuato, Leon Campus. 20 de Enero No. 929 Col. Obregon, 37320, Leon, Guanajuato, Mexico
| | - Maria-Luisa Lazo-de-la-Vega-Monroy
- Medical Sciences Department, Health Sciences Division, University of Guanajuato, Leon Campus. 20 de Enero No. 929 Col. Obregon, 37320, Leon, Guanajuato, Mexico
| | - Silvio Zaina
- Medical Sciences Department, Health Sciences Division, University of Guanajuato, Leon Campus. 20 de Enero No. 929 Col. Obregon, 37320, Leon, Guanajuato, Mexico
| | - Myrna Sabanero
- Biology Department, Natural and Exact Sciences Division, University of Guanajuato, Guanajuato Campus, Guanajuato, Mexico
| | | | - Juan Manuel Malacara
- Medical Sciences Department, Health Sciences Division, University of Guanajuato, Leon Campus. 20 de Enero No. 929 Col. Obregon, 37320, Leon, Guanajuato, Mexico
| | - Gloria Barbosa-Sabanero
- Medical Sciences Department, Health Sciences Division, University of Guanajuato, Leon Campus. 20 de Enero No. 929 Col. Obregon, 37320, Leon, Guanajuato, Mexico.
| |
Collapse
|
16
|
Yang WL, Ma G, Zhou M, Aziz M, Yen HT, Marvropoulos SA, Ojamaa K, Wang P. Combined Administration of Human Ghrelin and Human Growth Hormone Attenuates Organ Injury and Improves Survival in Aged Septic Rats. Mol Med 2016; 22:124-135. [PMID: 26835699 DOI: 10.2119/molmed.2015.00255] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 01/21/2016] [Indexed: 01/03/2023] Open
Abstract
Sepsis is a major healthcare concern, especially in the elderly population. The use of an animal model closely resembling clinical conditions in this population may provide a better prediction in translating bench studies to the bedside. Ghrelin inhibits sympathetic nerve activity and inflammation in young septic animals; however, aged animals become hyporesponsive to ghrelin. In this study, we evaluated the efficacy of combined human ghrelin and growth hormone (GH) for sepsis treatment in the elderly utilizing a clinically relevant animal model of sepsis. Male Fischer 344 rats 22 to 24 months old were subjected to cecal ligation and puncture (CLP). Human ghrelin plus GH or vehicle (normal saline) was administered subcutaneously at 5 h after CLP. At 20 h after CLP, blood and tissue samples were collected for various analyses. Combined treatment attenuated serum levels of lactate, lactate dehydrogenase, creatinine, blood urea nitrogen, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in aged septic rats. The integrity of the microscopic structure in the lungs, liver and kidneys was well preserved after treatment. Expression of IL-6, TNF-α, macrophage inflammatory protein-2 and keratinocyte-derived chemokine as well as myeloperoxidase activity and caspase-3 activation were significantly reduced in the lungs and liver of treated rats. Moreover, treated rats showed an improvement in cardiovascular function and increased expression of ghrelin receptor and c-fos in the brainstem. Finally, the 10-d survival of aged septic rats was increased from 29% to 64% after combined treatment and was associated with less body weight loss. Our findings warrant the development of combined human ghrelin and GH for sepsis treatment in the geriatric population.
Collapse
Affiliation(s)
- Weng-Lang Yang
- TheraSource LLC, Manhasset, New York, United States of America.,Center for Immunology and Inflammation, The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
| | - Gaifeng Ma
- TheraSource LLC, Manhasset, New York, United States of America
| | - Mian Zhou
- Center for Immunology and Inflammation, The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
| | - Monowar Aziz
- Center for Immunology and Inflammation, The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
| | - Hao-Ting Yen
- TheraSource LLC, Manhasset, New York, United States of America
| | | | - Kaie Ojamaa
- Center for Immunology and Inflammation, The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
| | - Ping Wang
- Center for Immunology and Inflammation, The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
| |
Collapse
|
17
|
Villa-Osaba A, Gahete MD, Córdoba-Chacón J, de Lecea L, Pozo-Salas AI, Delgado-Lista FJ, Álvarez-Benito M, López-Miranda J, Luque RM, Castaño JP. Obesity alters gene expression for GH/IGF-I axis in mouse mammary fat pads: differential role of cortistatin and somatostatin. PLoS One 2015; 10:e0120955. [PMID: 25806796 PMCID: PMC4373840 DOI: 10.1371/journal.pone.0120955] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 02/10/2015] [Indexed: 12/03/2022] Open
Abstract
Locally produced growth hormone (GH) and IGF-I are key factors in the regulation of mammary gland (MG) development and may be important in breast cancer development/progression. Somatostatin (SST) and cortistatin (CORT) regulate GH/IGF-I axis at various levels, but their role in regulating GH/IGF-I in MGs remains unknown. Since obesity alters the expression of these systems in different tissues and is associated to MG (patho) physiology, we sought to investigate the role of SST/CORT in regulating GH/IGF-I system in the MGs of lean and obese mice. Therefore, we analyzed GH/IGF-I as well as SST/CORT and ghrelin systems expression in the mammary fat pads (MFPs) of SST- or CORT-knockout (KO) mice and their respective littermate-controls fed a low-fat (LF) or a high-fat (HF) diet for 16 wks. Our results demonstrate that the majority of the components of GH/IGF-I, SST/CORT and ghrelin systems are locally expressed in mouse MFP. Expression of elements of the GH/IGF-I axis was significantly increased in MFPs of HF-fed control mice while lack of endogenous SST partially suppressed, and lack of CORT completely blunted, the up-regulation observed in obese WT-controls. Since SST/CORT are known to exert an inhibitory role on the GH/IGFI axis, the increase in SST/CORT-receptor sst2 expression in MFPs of HF-fed CORT- and SST-KOs together with an elevation on circulating SST in CORT-KOs could explain the differences observed. These results offer new information on the factors (GH/IGF-I axis) involved in the endocrine/metabolic dysregulation of MFPs in obesity, and suggest that CORT is not a mere SST sibling in regulating MG physiology.
Collapse
Affiliation(s)
- Alicia Villa-Osaba
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain
| | - Manuel D. Gahete
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain
| | - José Córdoba-Chacón
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain
- Department of Medicine, University of Illinois at Chicago and Jesse Brown Veteran Affairs Medical Center, Research and Development Division, Chicago, Illinois, United States of America
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, United States of America
| | - Ana I. Pozo-Salas
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
| | - Francisco Javier Delgado-Lista
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
- Lipids and Atherosclerosis Unit, Department of Medicine, Reina Sofía University Hospital, Córdoba, Spain
| | - Marina Álvarez-Benito
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
- Mammary Gland Unit, Reina Sofía University Hospital, Córdoba, Spain
| | - José López-Miranda
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain
- Lipids and Atherosclerosis Unit, Department of Medicine, Reina Sofía University Hospital, Córdoba, Spain
| | - Raúl M. Luque
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain
| | - Justo P. Castaño
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain
| |
Collapse
|
18
|
Wang Z, Yang WL, Jacob A, Aziz M, Wang P. Human ghrelin mitigates intestinal injury and mortality after whole body irradiation in rats. PLoS One 2015; 10:e0118213. [PMID: 25671547 PMCID: PMC4325005 DOI: 10.1371/journal.pone.0118213] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 01/12/2015] [Indexed: 01/13/2023] Open
Abstract
Widespread use of ionizing radiation has led to the realization of the danger associated with radiation exposure. Although studies in radiation countermeasures were initiated a half century ago, an effective therapy for a radiomitigator has not been identified. Ghrelin is a gastrointestinal hormone, and administration of ghrelin is protective in animal models of injuries including radiation combined injury. To test whether ghrelin can be protective in whole body irradiaton (WBI) alone, male Sprague Dawley (SD) rats were treated with human ghrelin (20 nmol/rat) daily for 6 days starting at either 24 h or 48 h after 10 Gray (Gy) WBI and survival outcome was examined. The 10 Gy WBI produced a LD70/30 model in SD rats (30% survival in 30 days). The survival rate in rats treated with ghrelin starting at 24 h was significantly improved to 63% and when treatment was initiated at 48 h, the survival remained at 61%. At 7 days post WBI, plasma ghrelin was significantly reduced from the control value. Ghrelin treatment starting at 24 h after WBI daily for 6 days improved histological appearance of the intestine, reduced gut permeability, serum endotoxin levels and bacterial translocation to the liver by 38%, 42% and 61%, respectively at day 7 post WBI. Serum glucose and albumin were restored to near control levels with treatment. Ghrelin treatment also attenuated WBI-induced intestinal apoptosis by 62% as evidenced by TUNEL staining. The expression of anti-apoptotic cell regulator Bcl-xl was decreased by 38% in the vehicle and restored to 75% of the control with ghrelin treatment. Increased expression of intestinal CD73 and pAkt were observed with ghrelin treatment, indicating protection of the intestinal epithelium after WBI. These results indicate that human ghrelin attenuates intestinal injury and mortality after WBI. Thus, human ghrelin can be developed as a novel mitigator for radiation injury.
Collapse
Affiliation(s)
- Zhimin Wang
- TheraSource LLC, Manhasset, NY, United States of America
| | - Weng Lang Yang
- Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, NY, United States of America
- TheraSource LLC, Manhasset, NY, United States of America
| | - Asha Jacob
- Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, NY, United States of America
- TheraSource LLC, Manhasset, NY, United States of America
| | - Monowar Aziz
- Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, NY, United States of America
| | - Ping Wang
- Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, NY, United States of America
- * E-mail:
| |
Collapse
|
19
|
Meyer RM, Burgos-Robles A, Liu E, Correia SS, Goosens KA. A ghrelin-growth hormone axis drives stress-induced vulnerability to enhanced fear. Mol Psychiatry 2014; 19:1284-94. [PMID: 24126924 PMCID: PMC3988273 DOI: 10.1038/mp.2013.135] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 08/20/2013] [Accepted: 09/09/2013] [Indexed: 01/05/2023]
Abstract
Hormones in the hypothalamus-pituitary-adrenal (HPA) axis mediate many of the bodily responses to stressors, yet there is no clear relationship between the levels of these hormones and stress-associated mental illnesses such as posttraumatic stress disorder (PTSD). Therefore, other hormones are likely to be involved in this effect of stress. Here we used a rodent model of PTSD in which rats repeatedly exposed to a stressor display heightened fear learning following auditory Pavlovian fear conditioning. Our results show that stress-related increases in circulating ghrelin, a peptide hormone, are necessary and sufficient for stress-associated vulnerability to exacerbated fear learning and these actions of ghrelin occur in the amygdala. Importantly, these actions are also independent of the classic HPA stress axis. Repeated systemic administration of a ghrelin receptor agonist enhanced fear memory but did not increase either corticotropin-releasing factor (CRF) or corticosterone. Repeated intraamygdala infusion of a ghrelin receptor agonist produced a similar enhancement of fear memory. Ghrelin receptor antagonism during repeated stress abolished stress-related enhancement of fear memory without blunting stress-induced corticosterone release. We also examined links between ghrelin and growth hormone (GH), a major downstream effector of the ghrelin receptor. GH protein was upregulated in the amygdala following chronic stress, and its release from amygdala neurons was enhanced by ghrelin receptor stimulation. Virus-mediated overexpression of GH in the amygdala was also sufficient to increase fear. Finally, virus-mediated overexpression of a GH receptor antagonist was sufficient to block the fear-enhancing effects of repeated ghrelin receptor stimulation. Thus, ghrelin requires GH in the amygdala to exert fear-enhancing effects. These results suggest that ghrelin mediates a novel branch of the stress response and highlight a previously unrecognized role for ghrelin and growth hormone in maladaptive changes following prolonged stress.
Collapse
Affiliation(s)
- Retsina M. Meyer
- McGovern Institute for Brain Research and the Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 43 Vassar St, Cambridge, MA 02139, USA
| | - Anthony Burgos-Robles
- McGovern Institute for Brain Research and the Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 43 Vassar St, Cambridge, MA 02139, USA
| | - Elizabeth Liu
- McGovern Institute for Brain Research and the Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 43 Vassar St, Cambridge, MA 02139, USA
| | - Susana S. Correia
- McGovern Institute for Brain Research and the Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 43 Vassar St, Cambridge, MA 02139, USA
| | - Ki A. Goosens
- McGovern Institute for Brain Research and the Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 43 Vassar St, Cambridge, MA 02139, USA
| |
Collapse
|
20
|
Mani BK, Walker AK, Lopez Soto EJ, Raingo J, Lee CE, Perelló M, Andrews ZB, Zigman JM. Neuroanatomical characterization of a growth hormone secretagogue receptor-green fluorescent protein reporter mouse. J Comp Neurol 2014; 522:3644-66. [PMID: 24825838 PMCID: PMC4142102 DOI: 10.1002/cne.23627] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 05/08/2014] [Accepted: 05/09/2014] [Indexed: 12/15/2022]
Abstract
Growth hormone secretagogue receptor (GHSR) 1a is the only molecularly identified receptor for ghrelin, mediating ghrelin-related effects on eating, body weight, and blood glucose control, among others. The expression pattern of GHSR within the brain has been assessed previously by several neuroanatomical techniques. However, inherent limitations to these techniques and the lack of reliable anti-GHSR antibodies and reporter rodent models that identify GHSR-containing neurons have prevented a more comprehensive functional characterization of ghrelin-responsive neurons. Here we have systematically characterized the brain expression of an enhanced green fluorescence protein (eGFP) transgene controlled by the Ghsr promoter in a recently reported GHSR reporter mouse. Expression of eGFP in coronal brain sections was compared with GHSR mRNA expression detected in the same sections by in situ hybridization histochemistry. eGFP immunoreactivity was detected in several areas, including the prefrontal cortex, insular cortex, olfactory bulb, amygdala, and hippocampus, which showed no or low GHSR mRNA expression. In contrast, eGFP expression was low in several midbrain regions and in several hypothalamic nuclei, particularly the arcuate nucleus, where robust GHSR mRNA expression has been well-characterized. eGFP expression in several brainstem nuclei showed high to moderate degrees of colocalization with GHSR mRNA labeling. Further quantitative PCR and electrophysiological analyses of eGFP-labeled hippocampal cells confirmed faithful expression of eGFP within GHSR-containing, ghrelin-responsive neurons. In summary, the GHSR-eGFP reporter mouse model may be a useful tool for studying GHSR function, particularly within the brainstem and hippocampus; however, it underrepresents GHSR expression in nuclei within the hypothalamus and midbrain.
Collapse
Affiliation(s)
- Bharath K. Mani
- Division of Hypothalamic Research and Division of Endocrinology & Metabolism, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Angela K. Walker
- Division of Hypothalamic Research and Division of Endocrinology & Metabolism, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Eduardo J. Lopez Soto
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology, Buenos Aires, Argentina
| | - Jesica Raingo
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology, Buenos Aires, Argentina
| | - Charlotte E. Lee
- Division of Hypothalamic Research and Division of Endocrinology & Metabolism, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Mario Perelló
- Laboratory of Electrophysiology, Multidisciplinary Institute of Cell Biology, Buenos Aires, Argentina
| | - Zane B. Andrews
- Department of Physiology, Faculty of Medicine, Monash University, Melbourne, Victoria, Australia
| | - Jeffrey M. Zigman
- Division of Hypothalamic Research and Division of Endocrinology & Metabolism, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| |
Collapse
|
21
|
The cardiovascular action of hexarelin. JOURNAL OF GERIATRIC CARDIOLOGY : JGC 2014; 11:253-8. [PMID: 25278975 PMCID: PMC4178518 DOI: 10.11909/j.issn.1671-5411.2014.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 05/25/2014] [Accepted: 07/10/2014] [Indexed: 11/21/2022]
Abstract
Hexarelin, a synthetic growth hormone-releasing peptide, can bind to and activate the growth hormone secretagogue receptor (GHSR) in the brain similar to its natural analog ghrelin. However, the peripheral distribution of GHSR in the heart and blood vessels suggests that hexarelin might have direct cardiovascular actions beyond growth hormone release and neuroendocrine effects. Furthermore, the non-GHSR CD36 had been demonstrated to be a specific cardiac receptor for hexarelin and to mediate its cardioprotective effects. When compared with ghrelin, hexarelin is chemically more stable and functionally more potent. Therefore, it may be a promising therapeutic agent for some cardiovascular conditions. In this concise review, we discuss the current evidence for the cardiovascular action of hexarelin.
Collapse
|
22
|
Sivertsen B, Holliday N, Madsen AN, Holst B. Functionally biased signalling properties of 7TM receptors - opportunities for drug development for the ghrelin receptor. Br J Pharmacol 2014; 170:1349-62. [PMID: 24032557 DOI: 10.1111/bph.12361] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 06/17/2013] [Accepted: 08/06/2013] [Indexed: 12/23/2022] Open
Abstract
UNLABELLED The ghrelin receptor is a 7 transmembrane (7TM) receptor involved in a variety of physiological functions including growth hormone secretion, increased food intake and fat accumulation as well as modulation of reward and cognitive functions. Because of its important role in metabolism and energy expenditure, the ghrelin receptor has become an important therapeutic target for drug design and the development of anti-obesity compounds. However, none of the compounds developed so far have been approved for commercial use. Interestingly, the ghrelin receptor is able to signal through several different signalling pathways including Gαq , Gαi/o , Gα12/13 and arrestin recruitment. These multiple signalling pathways allow for functionally biased signalling, where one signalling pathway may be favoured over another either by selective ligands or through mutations in the receptor. In the present review, we have described how ligands and mutations in the 7TM receptor may bias the receptors to favour either one G-protein over another or to promote G-protein independent signalling pathways rather than G-protein-dependent pathways. For the ghrelin receptor, both agonist and inverse agonists have been demonstrated to signal more strongly through the Gαq -coupled pathway than the Gα12/13 -coupled pathway. Similarly a ligand that promotes Gαq coupling over Gαi coupling has been described and it has been suggested that several different active conformations of the receptor may exist dependent on the properties of the agonist. Importantly, ligands with such biased signalling properties may allow the development of drugs that selectively modulate only the therapeutically relevant physiological functions, thereby decreasing the risk of side effects. LINKED ARTICLES This article is part of a themed section on Neuropeptides. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.170.issue-7.
Collapse
Affiliation(s)
- B Sivertsen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, the Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | | | | | | |
Collapse
|
23
|
Intraportal infusion of ghrelin could inhibit glucose-stimulated GLP-1 secretion by enteric neural net in Wistar rat. BIOMED RESEARCH INTERNATIONAL 2014; 2014:923564. [PMID: 25247193 PMCID: PMC4160649 DOI: 10.1155/2014/923564] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 08/04/2014] [Indexed: 12/21/2022]
Abstract
As a regulator of food intake and energy metabolism, the role of ghrelin in glucose metabolism is still not fully understood. In this study, we determined the in vivo effect of ghrelin on incretin effect. We demonstrated that ghrelin inhibited the glucose-stimulated release of glucagon-like peptide-1 (GLP-1) when infused into the portal vein of Wistar rat. Hepatic vagotomy diminished the inhibitory effect of ghrelin on glucose-stimulated GLP-1 secretion. In addition, phentolamine, a nonselective α receptor antagonist, could recover the decrease of GLP-1 release induced by ghrelin infusion. Pralmorelin (an artificial growth hormone release peptide) infusion into the portal vein could also inhibit the glucose-stimulated release of GLP-1. And growth hormone secretagogue receptor antagonist, [D-lys3]-GHRP-6, infusion showed comparable increases of glucose stimulated GLP-1 release compared to ghrelin infusion into the portal vein. The data showed that intraportal infusion of ghrelin exerted an inhibitory effect on GLP-1 secretion through growth hormone secretagogue receptor 1α (GHS1α receptor), which indicated that the downregulation of ghrelin secretion after food intake was necessary for incretin effect. Furthermore, our results suggested that the enteric neural net involved hepatic vagal nerve and sympathetic nerve mediated inhibition effect of ghrelin on incretin effect.
Collapse
|
24
|
The expression of GHS-R in primary neurons is dependent upon maturation stage and regional localization. PLoS One 2013; 8:e64183. [PMID: 23755116 PMCID: PMC3673981 DOI: 10.1371/journal.pone.0064183] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 04/12/2013] [Indexed: 01/03/2023] Open
Abstract
Ghrelin is a hormone with a crucial role in the regulation of appetite, regulation of inflammation, glucose metabolism and cell proliferation. In the brain ghrelin neurons are located in the cortex (sensorimotor area, cingular gyrus), and the fibres of ghrelin neurons in hypothalamus project directly to the dorsal vagal complex (DVC). Ghrelin binds the growth hormone secretagogue receptor (GHS-R) a G-protein-coupled receptor with a widespread tissue distribution, indeed these receptors are localized both in nonnervous, organs/tissues (i.e. adipose tissue, myocardium, adrenals, gonads, lung, liver, arteries, stomach, pancreas, thyroid, and kidney) as well as in central nervous system (CNS) and higher levels of expression in the pituitary gland and the hypothalamus and lower levels of expression in other organs, including brain. A GHS-R specific monoclonal antibody has been developed and characterized and through it we demonstrate that GHS-R is expressed in primary neurons and that its expression is dependent upon their developmental stage and shows differences according to the brain region involved, with a more pronounced expression in hippocampal rather than cortical neurons. A characterization of GHS-R within the central nervous system is of extreme importance in order to gain insights on its role in the modulation of neurodegenerative events such as Alzheimer’s disease.
Collapse
|
25
|
Vestergaard ET, Krag MB, Poulsen MM, Pedersen SB, Moller N, Jorgensen JOL, Jessen N. Ghrelin- and GH-induced insulin resistance: no association with retinol-binding protein-4. Endocr Connect 2013; 2:96-103. [PMID: 23781325 PMCID: PMC3682232 DOI: 10.1530/ec-13-0019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 05/07/2013] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Supraphysiological levels of ghrelin and GH induce insulin resistance. Serum levels of retinol-binding protein-4 (RBP4) correlate inversely with insulin sensitivity in patients with type 2 diabetes. We aimed to determine whether ghrelin and GH affect RBP4 levels in human subjects. MATERIALS AND METHODS To study GH-independent effects of ghrelin, seven hypopituitary men undergoing replacement therapy with GH and hydrocortisone were given ghrelin (5 pmol/kg per min) and saline infusions for 300 min in a randomized, double-blind, placebo-controlled, crossover design. Circulating RBP4 levels were measured at baseline and during a hyperinsulinemic-euglycemic clamp on both study days. To study the direct effects of GH, nine healthy men were treated with GH (2 mg at 2200 h) and placebo for 8 days in a randomized, double-blind, placebo-controlled, crossover study. Serum RBP4 levels were measured before and after treatment, and insulin sensitivity was measured by the hyperinsulinemic-euglycemic clamp technique. RESULTS Ghrelin acutely decreased peripheral insulin sensitivity. Serum RBP4 concentrations decreased in response to insulin infusion during the saline experiment (mg/l): 43.2±4.3 (baseline) vs 40.4±4.2 (clamp), P<0.001, but this effect was abrogated during ghrelin infusion (mg/l): 42.4±4.5 (baseline) vs 42.9±4.7 (clamp), P=0.73. In healthy subjects, serum RBP4 levels were not affected by GH administration (mg/l): 41.7±4.1 (GH) vs 43.8±4.6 (saline), P=0.09, although GH induced insulin resistance. CONCLUSIONS i) Serum RBP4 concentrations decrease in response to hyperinsulinemia, ii) ghrelin abrogates the inhibitory effect of insulin on circulating RBP4 concentrations, and iii) ghrelin as well as GH acutely induces insulin resistance in skeletal muscle without significant changes in circulating RBP4 levels.
Collapse
Affiliation(s)
- Esben Thyssen Vestergaard
- Medical Research LaboratoriesInstitute of Clinical Medicine, Aarhus UniversityNorrebrogade 44DK-8000, Aarhus CDenmark
- Department of Endocrinology and DiabetesAarhus University HospitalNorrebrogade 44DK-8000, Aarhus CDenmark
- Department of PediatricsRegional Hospital West JutlandGl. Landevej 61DK-7400, HerningDenmark
- Correspondence should be addressed to E T Vestergaard
| | - Morten B Krag
- Department of Endocrinology and DiabetesAarhus University HospitalNorrebrogade 44DK-8000, Aarhus CDenmark
| | - Morten M Poulsen
- Department of Endocrinology and DiabetesAarhus University HospitalTage-Hansens Gade 2DK-8000, Aarhus CDenmark
| | - Steen B Pedersen
- Department of Endocrinology and DiabetesAarhus University HospitalTage-Hansens Gade 2DK-8000, Aarhus CDenmark
| | - Niels Moller
- Medical Research LaboratoriesInstitute of Clinical Medicine, Aarhus UniversityNorrebrogade 44DK-8000, Aarhus CDenmark
- Department of Endocrinology and DiabetesAarhus University HospitalNorrebrogade 44DK-8000, Aarhus CDenmark
| | - Jens Otto Lunde Jorgensen
- Medical Research LaboratoriesInstitute of Clinical Medicine, Aarhus UniversityNorrebrogade 44DK-8000, Aarhus CDenmark
- Department of Endocrinology and DiabetesAarhus University HospitalNorrebrogade 44DK-8000, Aarhus CDenmark
| | - Niels Jessen
- Medical Research LaboratoriesInstitute of Clinical Medicine, Aarhus UniversityNorrebrogade 44DK-8000, Aarhus CDenmark
- Department of Endocrinology and DiabetesAarhus University HospitalNorrebrogade 44DK-8000, Aarhus CDenmark
| |
Collapse
|
26
|
Méquinion M, Langlet F, Zgheib S, Dickson S, Dehouck B, Chauveau C, Viltart O. Ghrelin: central and peripheral implications in anorexia nervosa. Front Endocrinol (Lausanne) 2013; 4:15. [PMID: 23549309 PMCID: PMC3581855 DOI: 10.3389/fendo.2013.00015] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 02/01/2013] [Indexed: 11/15/2022] Open
Abstract
Increasing clinical and therapeutic interest in the neurobiology of eating disorders reflects their dramatic impact on health. Chronic food restriction resulting in severe weight loss is a major symptom described in restrictive anorexia nervosa (AN) patients, and they also suffer from metabolic disturbances, infertility, osteopenia, and osteoporosis. Restrictive AN, mostly observed in young women, is the third largest cause of chronic illness in teenagers of industrialized countries. From a neurobiological perspective, AN-linked behaviors can be considered an adaptation that permits the endurance of reduced energy supply, involving central and/or peripheral reprograming. The severe weight loss observed in AN patients is accompanied by significant changes in hormones involved in energy balance, feeding behavior, and bone formation, all of which can be replicated in animals models. Increasing evidence suggests that AN could be an addictive behavior disorder, potentially linking defects in the reward mechanism with suppressed food intake, heightened physical activity, and mood disorder. Surprisingly, the plasma levels of ghrelin, an orexigenic hormone that drives food-motivated behavior, are increased. This increase in plasma ghrelin levels seems paradoxical in light of the restrained eating adopted by AN patients, and may rather result from an adaptation to the disease. The aim of this review is to describe the role played by ghrelin in AN focusing on its central vs. peripheral actions. In AN patients and in rodent AN models, chronic food restriction induces profound alterations in the « ghrelin » signaling that leads to the development of inappropriate behaviors like hyperactivity or addiction to food starvation and therefore a greater depletion in energy reserves. The question of a transient insensitivity to ghrelin and/or a potential metabolic reprograming is discussed in regard of new clinical treatments currently investigated.
Collapse
Affiliation(s)
- Mathieu Méquinion
- UMR INSERM 837, Development and Plasticity of Postnatal BrainLille, France
| | - Fanny Langlet
- UMR INSERM 837, Development and Plasticity of Postnatal BrainLille, France
| | - Sara Zgheib
- Pathophysiology of inflammatory of bone diseases, Université Lille Nord de France-ULCO – Lille 2Boulogne sur Mer, France
| | - Suzanne Dickson
- Department of Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of GothenburgGothenburg, Sweden
- Department of Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of GothenburgGothenburg, Sweden
| | - Bénédicte Dehouck
- UMR INSERM 837, Development and Plasticity of Postnatal BrainLille, France
- Université Lille Nord de France – Université d’ArtoisLiévin, France
| | - Christophe Chauveau
- Pathophysiology of inflammatory of bone diseases, Université Lille Nord de France-ULCO – Lille 2Boulogne sur Mer, France
| | - Odile Viltart
- UMR INSERM 837, Development and Plasticity of Postnatal BrainLille, France
- Université Lille Nord de France-USTL (Lille 1)Villeneuve d’Ascq, France
- *Correspondence: Odile Viltart, Development and Plasticity of the Postnatal Brain, Team 2, Jean-Pierre Aubert Research Center, UMR INSERM 837, Bât Biserte, 1 place de Verdun, 59,045 Lille cedex, France. e-mail:
| |
Collapse
|
27
|
Castagneto-Gissey L, Mingrone G. Insulin sensitivity and secretion modifications after bariatric surgery. J Endocrinol Invest 2012; 35:692-8. [PMID: 22732257 DOI: 10.3275/8470] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Type 2 diabetes mellitus is increasing over time as result of the obesity epidemics. In fact, the prevalence of Type 2 diabetes across Europe in 2010 was estimated to be 8.2% of the population and its projection for 2030 sees figures of 10.1%. This increase in the number of diabetic individuals has also dramatically raised the health expense, with spending on diabetes in Europe in 2010 accounting for 10% of the total healthcare cost. A meta-analysis of the literature evidenced that the clinical and laboratory manifestations of Type 2 diabetes are resolved in 78.1%, and are improved in 86.6% of obese patients (body mass index >35 kg/m²) after bariatric surgery. However, a gradation of effects of different surgical techniques in improving glucose control does exist, with the largest and durable effects observed in prevalently malabsorptive procedures. The outcome of bariatric surgery on insulin sensitivity and secretion is different in relation to the type of operation performed. In fact, while Roux-en-Y Gastric Bypass enhances insulin secretion after a meal thus improving glucose metabolism, Bilio-Pancreatic Diversion acts through the amelioration of insulin sensitivity allowing a subsequent reduction of insulin hypersecretion, which is a typical feature of the insulin resistance state. Gastric banding action is mediated uniquely through the weight loss, and the effect of sleeve gastrectomy is still to be elucidated. Incretin secretion is dramatically increased under nutrient stimulation after gastric bypass leading, probably, to an overstimulation of pancreatic β-cells resulting in the increase of insulin secretion.
Collapse
|
28
|
Liang QH, Jiang Y, Zhu X, Cui RR, Liu GY, Liu Y, Wu SS, Liao XB, Xie H, Zhou HD, Wu XP, Yuan LQ, Liao EY. Ghrelin attenuates the osteoblastic differentiation of vascular smooth muscle cells through the ERK pathway. PLoS One 2012; 7:e33126. [PMID: 22514603 PMCID: PMC3326017 DOI: 10.1371/journal.pone.0033126] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 02/06/2012] [Indexed: 11/21/2022] Open
Abstract
Vascular calcification results from osteoblastic differentiation of vascular smooth muscle cells (VSMCs) and is a major risk factor for cardiovascular events. Ghrelin is a newly discovered bioactive peptide that acts as a natural endogenous ligand of the growth hormone secretagog receptor (GHSR). Several studies have identified the protective effects of ghrelin on the cardiovascular system, however research on the effects and mechanisms of ghrelin on vascular calcification is still quite rare. In this study, we determined the effect of ghrelin on osteoblastic differentiation of VSMCs and investigated the mechanism involved using the two universally accepted calcifying models of calcifying vascular smooth muscle cells (CVSMCs) and beta-glycerophosphate (beta-GP)-induced VSMCs. Our data demonstrated that ghrelin inhibits osteoblastic differentiation and mineralization of VSMCs due to decreased alkaline phosphatase (ALP) activity, Runx2 expression, bone morphogenetic protein-2 (BMP-2) expression and calcium content. Further study demonstrated that ghrelin exerted this suppression effect via an extracellular signal-related kinase (ERK)-dependent pathway and that the suppression effect of ghrelin was time dependent and dose dependent. Furthermore, inhibition of the growth hormone secretagog receptor (GHSR), the ghrelin receptor, by siRNA significantly reversed the activation of ERK by ghrelin. In conclusion, our study suggests that ghrelin may inhibit osteoblastic differentiation of VSMCs through the GHSR/ERK pathway.
Collapse
Affiliation(s)
- Qiu-Hua Liang
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Yi Jiang
- Department of Pathology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Xiao Zhu
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Rong-Rong Cui
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
- Department of Pediatrics, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Guan-Ying Liu
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Yuan Liu
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Shan-Shan Wu
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Xiao-Bo Liao
- Department of Cardiothoracic Surgery, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Hui Xie
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Hou-De Zhou
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Xian-Ping Wu
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
| | - Ling-Qing Yuan
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
- * E-mail: (LQY); (EYL)
| | - Er-Yuan Liao
- Institute of Metabolism and Endocrinology, the Second Xiang-Ya Hospital, Central South University, Changsha, People's Republic of China
- * E-mail: (LQY); (EYL)
| |
Collapse
|
29
|
Qi L, Cui X, Dong W, Barrera R, Nicastro J, Coppa GF, Wang P, Wu R. Ghrelin attenuates brain injury after traumatic brain injury and uncontrolled hemorrhagic shock in rats. Mol Med 2012; 18:186-93. [PMID: 22160303 DOI: 10.2119/molmed.2011.00390] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 11/29/2011] [Indexed: 11/06/2022] Open
Abstract
Traumatic brain injury (TBI) and hemorrhagic shock often occur concomitantly due to multiple injuries. Gastrointestinal dysfunction occurs frequently in patients with TBI. However, whether alterations in the gastrointestinal system are involved in modulating neuronal damage and recovery after TBI is largely neglected. Ghrelin is a "gut-brain" hormone with multiple functions including antiinflammation and antiapoptosis. The purpose of this study was to determine whether ghrelin attenuates brain injury in a rat model of TBI and uncontrolled hemorrhage (UH). To study this, brain injury was induced by dropping a 450-g weight from 1.5 m onto a steel helmet attached to the skull of male adult rats. Immediately after TBI, a midline laparotomy was performed and both lumbar veins were isolated and severed at the junction with the vena cava. At 45 min after TBI/UH, ghrelin (4, 8 or 16 nmol/rat) or 1 mL normal saline (vehicle) was intravenously administered. Brain levels of TNF-α and IL-6, and cleaved PARP-1 levels in the cortex were measured at 4 h after TBI/UH. Beam balance test, forelimb placing test and hindlimb placing test were used to assess sensorimotor and reflex function. In additional groups of animals, ghrelin (16 nmol/rat) or vehicle was subcutaneously (s.c.) administered daily for 10 d after TBI/UH. The animals were monitored for 28 d to record body weight changes, neurological severity scale and survival. Our results showed that ghrelin downregulated brain levels of TNF-α and IL-6, reduced cortical levels of cleaved PARP-1, improved sensorimotor and reflex functions, and decreased mortality after TBI/UH. Thus, ghrelin has a great potential to be further developed as an effective resuscitation approach for the trauma victims with brain injury and severe blood loss.
Collapse
Affiliation(s)
- Lei Qi
- The Feinstein Institute for Medical Research, Manhasset, New York, United States of America
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Ohta K, Laborde N, Kajiya M, Shin J, Zhu T, Thondukolam A, Min C, Kamata N, Karimbux N, Stashenko P, Kawai T. Expression and possible immune-regulatory function of ghrelin in oral epithelium. J Dent Res 2011; 90:1286-92. [PMID: 21865591 PMCID: PMC3188459 DOI: 10.1177/0022034511420431] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 06/24/2011] [Accepted: 07/04/2011] [Indexed: 12/21/2022] Open
Abstract
Originally found in stomach mucosa, ghrelin is a peptide appetite hormone that has been implicated as an immuno-modulatory factor. Ghrelin has also been found in salivary glands and saliva; however, its expression patterns and biological properties in the oral cavity remain unclear. Therefore, we investigated the expression patterns of ghrelin in saliva, gingival crevicular fluid (GCF), and gingival tissue, as well as its in vitro effects on IL-8 production by TNF-α or LPS-stimulated oral epithelial cells. In the clinical samples obtained from 12 healthy volunteers, the concentration of ghrelin in GCF remarkably exceeded that detected in saliva. The expression of ghrelin mRNAs and growth hormone secretagogue (GHS) receptors could be detected in human oral epithelial cells. Immunohistochemical analysis revealed the expression of ghrelin in gingival epithelium, as well as in fibroblasts in the lamina propria. Ghrelin increased intracellular calcium mobilization and cAMP levels in oral epithelial cells, suggesting that ghrelin acts on epithelial cells to induce cell signaling. Furthermore, synthetic ghrelin inhibited the production of IL-8 from TNF-α or LPS-stimulated oral epithelial cells. These results indicate that ghrelin produced in the oral cavity appears to play a regulatory role in innate immune responses to inflammatory infection.
Collapse
Affiliation(s)
- K. Ohta
- Department of Immunology, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Oral and Maxillofacial Surgery, Division of Cervico-Gnathostomatology, Programs for Applied Biomedicine, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - N.J. Laborde
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - M. Kajiya
- Department of Immunology, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - J. Shin
- Department of Immunology, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - T. Zhu
- Department of Immunology, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - A.K. Thondukolam
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - C. Min
- Department of Immunology, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - N. Kamata
- Department of Oral and Maxillofacial Surgery, Division of Cervico-Gnathostomatology, Programs for Applied Biomedicine, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - N.Y. Karimbux
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| | - P. Stashenko
- Department of Cytokine Biology, Forsyth Institute, 245 1st Street, Cambridge, MA 02142, USA
| | - T. Kawai
- Department of Immunology, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA
| |
Collapse
|
31
|
Rajan D, Wu R, Shah KG, Jacob A, Coppa GF, Wang P. Human ghrelin protects animals from renal ischemia-reperfusion injury through the vagus nerve. Surgery 2011; 151:37-47. [PMID: 21943641 DOI: 10.1016/j.surg.2011.06.027] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 06/16/2011] [Indexed: 02/03/2023]
Abstract
BACKGROUND Acute kidney injury secondary to renal ischemia and reperfusion injury is widely prevalent. Ghrelin, which is a stomach-derived peptide, has been shown to be anti-inflammatory. The purpose of this study was to examine whether human ghrelin has any beneficial effects after renal ischemia and reperfusion injury, and if so, whether ghrelin's action in renal ischemia and reperfusion injury is mediated by the vagus nerve. METHODS Male adult rats were subjected to renal ischemia and reperfusion by bilateral renal pedicle clamping for 60 min, treated intravenously with human ghrelin (4 nmol/rat) or normal saline (vehicle) immediately after reperfusion. After 24 h, the animals were killed and samples were harvested. In separate groups, subdiaphragmatic vagotomy prior to renal ischemia and reperfusion was performed, treated with human ghrelin or vehicle, and at 24 h, blood and organs were harvested. RESULTS Renal ischemia and reperfusion injury caused significant increases in the serum levels of tissue injury markers compared with the sham operation. Human ghrelin treatment attenuated serum creatinine and blood urea nitrogen significantly by 55% and 53%, and liver enzymes (aminotransferase [AST] and alanine aminotransferase [ALT]) by 20% and 24%, respectively, compared with the vehicle-treated groups. Tissue water contents, plasma and kidney interleukin-6, and kidney myeloperoxidase activity were decreased. Bcl-2/Bax ratio was increased, and histology of the kidneys was improved. More importantly, prior vagotomy abolished ghrelin's protective effect in tissue injury markers and tissue water contents in renal ischemia and reperfusion injured animals. CONCLUSION Human ghrelin treatment in renal ischemia and reperfusion injured rats attenuated systemic and kidney-specific inflammatory responses. The protection of human ghrelin in renal ischemia and reperfusion injury was mediated by the vagus nerve. These data suggest that ghrelin can be developed as a novel treatment for patients with acute kidney injury induced by renal ischemia and reperfusion injury.
Collapse
Affiliation(s)
- Derry Rajan
- Department of Surgery, North Shore University Hospital and Long Island Jewish Medical Center, Manhasset, NY 11030, USA
| | | | | | | | | | | |
Collapse
|
32
|
Zhang G, Yin X, Qi Y, Pendyala L, Chen J, Hou D, Tang C. Ghrelin and cardiovascular diseases. Curr Cardiol Rev 2011; 6:62-70. [PMID: 21286280 PMCID: PMC2845796 DOI: 10.2174/157340310790231662] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 03/27/2009] [Accepted: 04/03/2009] [Indexed: 01/19/2023] Open
Abstract
Ghrelin, a newly discovered bioactive peptide, is a natural endogenous ligand of the growth hormone (GH) secretagogue receptor and initially identified as a strong stimulant for the release of GH. Subsequent research has shown that ghrelin and its various receptors are ubiquitous in many other organs and tissues. Moreover, they participate in the regulation of appetite, energy, bodyweight, metabolism of glucose and fat, as well as modulation of gastrointestinal, cardiovascular, pulmonary, immune functions and cell proliferation/apoptosis. Increasing evidence has demonstrated that ghrelin has a close relationship with cardiovascular system. Ghrelin and its receptors are widely distributed in cardiovascular tissues, and there is no doubt that the effects of ghrelin in the cardiovascular system are mediated not only via its growth-hormone-releasing effect but also by its direct effects on the heart. Exogenous administration of ghrelin can dilate peripheral blood vessels, constrict coronary artery, improve endothelial function, as well as inhibit myocardial cell apoptosis. So, ghrelin may have cardiovascular protective effect, including lowering of blood pressure, regulation of atherosclerosis, and protection from ischemia/reperfusion injury as well as improving the prognosis of myocardial infarction and heart failure. Some of these new functions of ghrelin may provide new potential therapeutic opportunities for ghrelin in cardiovascular medicine. In this paper, we will review the existing evidence for cardiovascular effects of ghrelin, including the cardiovascular function, the variations in ghrelin plasma levels in pathophysiologicalogical conditions, the possible protective mechanisms of ghrelin, as well as its future potential therapeutic roles.
Collapse
Affiliation(s)
- Gaigai Zhang
- Cardiology Department, the First Affiliated Hospital of Harbin Medical University, Harbin,P. R. China 150081
| | | | | | | | | | | | | |
Collapse
|
33
|
Potter R, Horti AG, Ravert HT, Holt DP, Finley P, Scheffel U, Dannals RF, Wahl RL. Synthesis and in vivo evaluation of (S)-6-(4-fluorophenoxy)-3-((1-[11C]methylpiperidin-3-yl)methyl)-2-o-tolylquinazolin-4(3H)-one, a potential PET tracer for growth hormone secretagogue receptor (GHSR). Bioorg Med Chem 2011; 19:2368-72. [PMID: 21388815 DOI: 10.1016/j.bmc.2011.02.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 02/04/2011] [Accepted: 02/11/2011] [Indexed: 10/18/2022]
Abstract
The peptide hormone ghrelin mediates through action on its receptor, the growth hormone secretagogue receptor (GHSR), and is known to play an important role in a variety of metabolic functions including appetite stimulation, weight gain, and suppression of insulin secretion. In light of the fact that obesity is one of the major health problems plaguing the modern society, the ghrelin signaling system continues to remain an important and attractive pharmacological target for the treatment of obesity. In vivo imaging of the GHSR could shed light on the mechanism by which ghrelin affects feeding behavior and thus offers a new therapeutic perspective for the development of effective treatments. Recently, a series of piperidine-substituted quinazolinone derivatives was reported to be selective and potent GHSR antagonists with high binding affinities. Described herein is the synthesis, in vitro, and in vivo evaluation of (S)-6-(4-fluorophenoxy)-3-((1-[(11)C]methylpiperidin-3-yl)methyl)-2-o-tolylquinazolin-4(3H)-one ([(11)C]1), a potential PET radioligand for imaging GHSR.
Collapse
Affiliation(s)
- Rachel Potter
- Division of Nuclear Medicine, Department of Radiology, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287-0816, USA
| | | | | | | | | | | | | | | |
Collapse
|
34
|
SEDLÁČKOVÁ D, KOPEČKOVÁ J, PAPEŽOVÁ H, VYBÍRAL S, KVASNIČKOVÁ H, HILL M, NEDVÍDKOVÁ J. Changes of Plasma Obestatin, Ghrelin and NPY in Anorexia and Bulimia Nervosa Patients Before and After a High-Carbohydrate Breakfast. Physiol Res 2011; 60:165-73. [DOI: 10.33549/physiolres.931952] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Peptides ghrelin, obestatin and neuropeptide Y (NPY) play an important role in regulation of energy homeostasis, the imbalance of which is associated with eating disorders anorexia (AN) and bulimia nervosa (BN). The changes in ghrelin, obestatin and NPY plasma levels were investigated in AN and BN patients after administration of a high-carbohydrate breakfast (1604 kJ). Eight AN women (aged 25.4±1.9; BMI: 15.8±0.5), thirteen BN women (aged 22.0±1.05; BMI: 20.1±0.41) and eleven healthy women (aged 25.1±1.16; BMI: 20.9±0.40) were recruited for the study. We demonstrated increased fasting ghrelin in AN, but not in BN patients, while fasting obestatin and NPY were increased in both AN and BN patients compared to the controls. Administration of high-carbohydrate breakfast induced a similar relative decrease in ghrelin and obestatin plasma levels in all groups, while NPY remained increased in postprandial period in both patient groups. Ghrelin/obestatin ratio was lower in AN and BN compared to the controls. In conclusions, increased plasma levels of fasting NPY and its unchanged levels after breakfast indicate that NPY is an important marker of eating disorders AN and BN. Different fasting ghrelin and obestatin levels in AN and BN could demonstrate their diverse functions in appetite and eating suppression.
Collapse
Affiliation(s)
| | | | | | | | | | | | - J. NEDVÍDKOVÁ
- Institute of Endocrinology, Laboratory of Clinical and Experimental Neuroendocrinology, Prague, Czech Republic
| |
Collapse
|
35
|
Vestergaard ET, Buhl M, Gjedsted J, Madsen M, Jessen N, Nielsen S, Gaylinn BD, Liu J, Thorner MO, Moller N, Jorgensen JOL. Acute peripheral metabolic effects of intraarterial ghrelin infusion in healthy young men. J Clin Endocrinol Metab 2011; 96:468-77. [PMID: 21084392 PMCID: PMC5393419 DOI: 10.1210/jc.2010-1995] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
CONTEXT Ghrelin is the endogenous agonist for the growth hormone secretagogue receptor (GHS-R). Intravenous administration of ghrelin induces insulin resistance and hyperglycemia and increases the levels of free fatty acids (FFA). OBJECTIVE To investigate whether these effects are mediated directly by ghrelin in skeletal muscle tissue. DESIGN This study was single blinded, randomized, and placebo controlled. Eight healthy men (25.5 ± 3.1 years) received 240 min of intraarterial ghrelin infusion (4.2 ng × kg(-1) × min(-1)) into one femoral artery and intraarterial placebo infusion into the contralateral artery. Simultaneous blood samples were drawn from both femoral veins and muscle biopsies were obtained from both legs during both a basal period and during a hyperinsulinemic and euglycemic clamp period. RESULTS Ghrelin significantly elevated venous FFA levels and venous dilution of palmitate, suggestive of increased lipolysis. Glucose metabolism was unchanged, and there were no direct effects on pertinent enzymes in the insulin signaling cascade. The metabolic clearance rate of acyl ghrelin was 12.5 ± 3.3 ml × kg(-1) × min(-1). Acyl and desacyl ghrelin levels both increased. CONCLUSIONS The results of this study suggest that ghrelin may stimulate lipolysis directly in skeletal muscle.
Collapse
|
36
|
Kemp BA, Howell NL, Gray JT, Keller SR, Nass RM, Padia SH. Intrarenal ghrelin infusion stimulates distal nephron-dependent sodium reabsorption in normal rats. Hypertension 2011; 57:633-9. [PMID: 21220707 DOI: 10.1161/hypertensionaha.110.166413] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Ghrelin is a 28-amino acid peptide hormone that exerts powerful orexigenic effects. Ghrelin receptor expression has been reported in the kidney, but the role of ghrelin in the kidney is unknown. The present studies confirmed ghrelin receptor mRNA expression in the kidneys of normal Sprague Dawley rats (n=6) using reverse transcription polymerase chain reaction (PCR) and sequencing of the 588-bp PCR product. To test intrarenal ghrelin action, uninephrectomized rats received 3 cumulative 1-hour renal interstitial (RI) infusions of 5% dextrose in water (vehicle, n=21), ghrelin (n=10), ghrelin plus specific ghrelin receptor antagonist [D-Lys-3]-GHRP-6 (n=24), or [D-Lys-3]-GHRP-6 alone (n=32). Mean arterial pressure (MAP), urine sodium excretion rate (U(Na)V), glomerular filtration rate (GFR), fractional excretion of sodium (FE(Na)), and fractional excretion of lithium (FE(Li)) were calculated for each period. RI ghrelin infusion significantly decreased U(Na)V to 86 ± 4.9% (P<0.05), 74 ± 6.5% (P<0.01), and 62 ± 10% (P<0.01) of baseline during periods 1 to 3, respectively. Ghrelin also significantly decreased FE(Na) to 68 ± 11% (P<0.05), 57 ± 8.6% (P<0.001), and 59 ± 12% (P<0.01) of baseline, without changing GFR or FE(Li). Identical ghrelin infusions in the presence of [D-Lys-3]-GHRP-6 failed to permit reductions in U(Na)V or FE(Na). Following [D-Lys-3]-GHRP-6 infusion alone, U(Na)V increased from 0.06 ± 0.01 to 0.18 ± 0.03 μmol/min (P<0.0001). Concomitant increases in FE(Na) were also observed (0.23 ± 0.03% to 0.51 ± 0.06% [P<0.001]), without changes in MAP, GFR, or FE(Li). Together, these data introduce a novel intrarenal ghrelin-ghrelin receptor system, which, on activation, significantly increases Na(+) reabsorption at the level of the distal nephron.
Collapse
Affiliation(s)
- Brandon A Kemp
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia Health System, Charlottesville, VA 22908-1414, USA
| | | | | | | | | | | |
Collapse
|
37
|
Kaiya H, Koizumi Y, Konno N, Yamamoto K, Uchiyama M, Kangawa K, Miyazato M. Ghrelin Receptor in Two Species of Anuran Amphibian, Bullfrog (Rana catesbeiana), and Japanese Tree Frog (Hyla japonica). Front Endocrinol (Lausanne) 2011; 2:31. [PMID: 22654801 PMCID: PMC3356126 DOI: 10.3389/fendo.2011.00031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 08/26/2011] [Indexed: 12/28/2022] Open
Abstract
We have identified cDNA encoding a functional growth hormone secretagogue-receptor 1a (GHS-R1a, ghrelin receptor) in two species of anuran amphibian, the bullfrog (Rana catesbeiana), and the Japanese tree frog (Hyla japonica). Deduced receptor protein for bullfrog and Japanese tree frog (tree frog) was comprised of 374- and 371-amino acids, respectively. The two receptors shared 86% identity, and are grouped to the clade of the tetrapod homologs by phylogenetic analysis. In functional analyses, ghrelin and GHS-R1a agonists increased intracellular Ca(2+) concentration in GHS-R1a-transfected-HEK293 cell, but ligand selectivity of ghrelin with Ser(3) and Thr(3) was not observed between the two receptors. Bullfrog GHS-R1a mRNA was mainly expressed in the brain, stomach, and testis. In the brain, the gene expression was detected in the diencephalon and mesencephalon, but not in the pituitary. Tree frog GHS-R1a mRNA was predominantly expressed in the gastrointestinal tract and ovary, but not detected in the pituitary. In bullfrog stomach but not the brain, GHS-R1a mRNA expression increased after 10 days of fasting. For tree frog, GHS-R1a mRNA expression was increased in the brain, stomach and ventral skin by 10 days of fasting, and in the stomach and ventral skin by a dehydration treatment. Intracerebroventricular injection of ghrelin in dehydrated tree frog did not affect water absorption from the ventral skin. These results suggest that ghrelin is involved in energy homeostasis and possibly in osmoregulation in frogs.
Collapse
Affiliation(s)
- Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research InstituteSuita, Osaka, Japan
- *Correspondence: Hiroyuki Kaiya, Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan. e-mail:
| | - Yasushi Koizumi
- Department of Biological Science, Graduated School of Science and Engineering, University of ToyamaToyama, Japan
| | - Norifumi Konno
- Department of Biological Science, Graduated School of Science and Engineering, University of ToyamaToyama, Japan
| | - Kazutoshi Yamamoto
- Laboratory of Integrative Brain Science, Department of Biology, Waseda UniversityTokyo, Japan
| | - Minoru Uchiyama
- Department of Biological Science, Graduated School of Science and Engineering, University of ToyamaToyama, Japan
| | - Kenji Kangawa
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research InstituteSuita, Osaka, Japan
| | - Mikiya Miyazato
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research InstituteSuita, Osaka, Japan
| |
Collapse
|
38
|
Sudar E, Dobutovic B, Soskic S, Mandusic V, Zakula Z, Misirkic M, Vucicevic L, Janjetovic K, Trajkovic V, Mikhailidis DP, Isenovic ER. Regulation of inducible nitric oxide synthase activity/expression in rat hearts from ghrelin-treated rats. J Physiol Biochem 2010; 67:195-204. [PMID: 21107779 DOI: 10.1007/s13105-010-0063-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 11/09/2010] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to examine the effects of ghrelin on protein kinase B (Akt) and mitogen-activated protein kinase p42/44 (ERK1/2) activation as well as ghrelin effects on inducible nitric oxide (NO) synthase (iNOS; for gene Nos2) activity/expression in rat hearts. Male Wistar rats were treated with ghrelin (0.3 nmol/5 μl) or an equal volume of phosphate-buffered saline, injected every 24 h into the lateral cerebral ventricle for 5 days and 2 h after the last treatment the animals were sacrificed. Serum NO, L-arginine (L-Arg), and arginase activity were measured spectrophotometrically. For phosphorylation of Akt, ERK1/2, and iNOS protein expression, Western blot method was used. The expression of Nos2 mRNA was measured by the quantitative real-time polymerase chain reaction (qRT-PCR). Treatment with ghrelin significantly increased NO production in serum by 1.4-fold compared with control. The concentration of L-Arg was significantly higher in ghrelin-treated rats than in control while arginase activity was significantly lower in ghrelin-treated than in control hearts. Ghrelin treatment increased phosphorylation of Akt by 1.9-fold and ERK1/2 by 1.6-fold and increased iNOS expression by 2.5-fold compared with control. In addition, ghrelin treatment increased Nos2 gene expression by 2.2-fold as determined by qRT-PCR. These results indicate that ghrelin regulation of iNOS expression/activity is mediated via Akt/ERK1/2 signaling pathway. These results may be relevant to understanding molecular mechanisms underlying direct cardiovascular actions of ghrelin.
Collapse
Affiliation(s)
- Emina Sudar
- Laboratory of Radiobiology and Molecular Genetics, Institute Vinca, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Figlewicz DP, Sipols AJ. Energy regulatory signals and food reward. Pharmacol Biochem Behav 2010; 97:15-24. [PMID: 20230849 PMCID: PMC2897918 DOI: 10.1016/j.pbb.2010.03.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 02/26/2010] [Accepted: 03/09/2010] [Indexed: 12/23/2022]
Abstract
The hormones insulin, leptin, and ghrelin have been demonstrated to act in the central nervous system (CNS) as regulators of energy homeostasis, acting at medial hypothalamic sites. Here, we summarize research demonstrating that, in addition to direct homeostatic actions at the hypothalamus, CNS circuitry that subserves reward and is also a direct and indirect target for the action of these endocrine regulators of energy homeostasis. Specifically, insulin and leptin can decrease food reward behaviors and modulate the function of neurotransmitter systems and neural circuitry that mediate food reward, the midbrain dopamine (DA) and opioidergic pathways. Ghrelin can increase food reward behaviors, and support midbrain DA neuronal function. We summarize discussion of behavioral, systems, and cellular evidence in support of the contributions of reward circuitry to the homeostatic roles of these hormones in the CNS. The understanding of neuroendocrine modulation of food reward, as well as food reward modulation by diet and obesity, may point to new directions for therapeutic approaches to overeating or eating disorders.
Collapse
Affiliation(s)
- Dianne P Figlewicz
- Metabolism/Endocrinology, VA Puget Sound Health Care System, Seattle Division, Seattle, WA 98108, USA.
| | | |
Collapse
|
40
|
Continuous antagonism of the ghrelin receptor results in early induction of salt-sensitive hypertension. J Mol Neurosci 2010; 43:193-9. [PMID: 20596792 DOI: 10.1007/s12031-010-9414-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 06/15/2010] [Indexed: 12/15/2022]
Abstract
Ghrelin is a hormone that mediates a variety of physiological roles, such as stimulating appetite, initiating food intake, and modulating energy metabolism. Although it has been reported that a bolus injection of ghrelin decreases blood pressure, the effect of continuous ghrelin administration on vasoregulation has yet to be determined. We examined the longitudinal effect of ghrelin on vasoregulation using Dahl-Iwai salt-sensitive rats. In this model, a high-salt diet induced high blood pressure and increased ghrelin levels but reduced food intake. In salt-sensitive hypertension, cumulative food intake decreased, while both ghrelin messenger RNA levels and plasma ghrelin content increased. Continuous administration of a ghrelin receptor agonist, growth hormone releasing peptide-6 (GHRP-6), for 2 weeks by mini-osmotic pump did not change blood pressure values although the cumulative food intake recovered. In contrast, continuous administration of a ghrelin receptor antagonist, [D-Lys³]-GHRP-6, induced early elevations in blood pressure without changes in heart rate. Quantitative RT-PCR revealed high expression levels of genes involved in the catecholamine biosynthetic pathway, tyrosine hydroxylase and dopamine-β-hydroxylase, after continuous [D-Lys³]-GHRP-6 administration. These results indicate that continuous antagonism of the ghrelin receptor results in early induction of salt-sensitive hypertension in this animal model and suggests that increases in autonomic nervous activity induced by ghrelin receptor antagonism are responsible, as indicated by the high expression levels of genes in the catecholamine biosynthetic pathway.
Collapse
|
41
|
Ferrini F, Salio C, Lossi L, Merighi A. Ghrelin in central neurons. Curr Neuropharmacol 2010; 7:37-49. [PMID: 19721816 PMCID: PMC2724662 DOI: 10.2174/157015909787602779] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 08/15/2008] [Accepted: 09/01/2008] [Indexed: 12/20/2022] Open
Abstract
Ghrelin, an orexigenic peptide synthesized by endocrine cells of the gastric mucosa, is released in the bloodstream in response to a negative energetic status. Since discovery, the hypothalamus was identified as the main source of ghrelin in the CNS, and effects of the peptide have been mainly observed in this area of the brain. In recent years, an increasing number of studies have reported ghrelin synthesis and effects in specific populations of neurons also outside the hypothalamus. Thus, ghrelin activity has been described in midbrain, hindbrain, hippocampus, and spinal cord. The spectrum of functions and biological effects produced by the peptide on central neurons is remarkably wide and complex. It ranges from modulation of membrane excitability, to control of neurotransmitter release, neuronal gene expression, and neuronal survival and proliferation. There is not at present a general consensus concerning the source of ghrelin acting on central neurons. Whereas it is widely accepted that the hypothalamus represents the most important endogenous source of the hormone in CNS, the existence of extra-hypothalamic ghrelin-synthesizing neurons is still controversial. In addition, circulating ghrelin can theoretically be another natural ligand for central ghrelin receptors. This paper gives an overview on the distribution of ghrelin and its receptor across the CNS and critically analyses the data available so far as regarding the effects of ghrelin on central neurotransmission.
Collapse
Affiliation(s)
- F Ferrini
- Dipartimento di Morfofisiologia Veterinaria, Università di Torino, Via Leonardo da Vinci 44, 10095, Grugliasco, Italy
| | | | | | | |
Collapse
|
42
|
Plasma ghrelin levels and polymorphisms of ghrelin gene in Chinese obese children and adolescents. Ir J Med Sci 2010; 179:345-9. [PMID: 20517652 DOI: 10.1007/s11845-010-0494-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 05/03/2010] [Indexed: 10/19/2022]
Abstract
AIM To evaluate the role of fasting plasma ghrelin levels [ln(ghrelin)] and polymorphisms of ghrelin gene in Chinese obese children. METHODS Genotyping for ghrelin polymorphism was performed in 230 obese and 100 normal weight children. Among them, plasma ghrelin levels were measured in 91 obese and 23 health subjects. RESULTS (1) Bivariate correlation analysis showed the ln(ghrelin) was inversely correlated with abnormality of glucose metabolism (r = -0.240, P = 0.023). Stepwise multiple regression analysis showed that abnormality of glucose metabolism was an independent determinant of plasma ghrelin levels (P = 0.023). (2) There was no difference in frequency of Leu72Met polymorphisms between obese and control groups (36.09 vs. 41.00%). CONCLUSION Ghrelin is associated with obesity in childhood, especially associated with the glucose homeostasis. Lower ghrelin levels might be a result of obesity, but not a cause of obesity. The Leu72Met polymorphism of ghrelin gene is not associated with obesity and metabolic syndrome in Chinese children.
Collapse
|
43
|
Koch A, Sanson E, Helm A, Voigt S, Trautwein C, Tacke F. Regulation and prognostic relevance of serum ghrelin concentrations in critical illness and sepsis. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2010; 14:R94. [PMID: 20500817 PMCID: PMC2911731 DOI: 10.1186/cc9029] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 05/14/2010] [Accepted: 05/25/2010] [Indexed: 12/28/2022]
Abstract
Introduction Ghrelin has been recently identified as a mediator of various beneficial effects in animal models of sepsis. At present, no data are available concerning specific properties of ghrelin in critically ill patients from large cohorts. In order to identify possible pathogenic functions of ghrelin in critically ill patients and human sepsis from a clinical point of view, we aimed at analyzing ghrelin serum concentrations in a large cohort of well characterized patients with critical illness. Methods A total of 170 critically ill patients (122 with sepsis, 48 without sepsis) were studied prospectively on admission to the Medical intensive care unit (ICU) and compared to 60 healthy controls. Careful assessment of clinical data, various laboratory parameters, metabolic and endocrine functions as well as investigational inflammatory cytokine profiles have been performed, and patients were followed for approximately three years. Results Ghrelin serum concentrations are elevated in critically ill patients as compared to healthy controls, but do not differ between sepsis and non-sepsis patients. The underlying etiologies of critical diseases are not associated with ghrelin serum levels. Neither pre-existing diabetes mellitus nor body mass index is correlated to serum ghrelin concentrations. Ghrelin is not correlated to markers of inflammation or hepatic function in critically ill patients. In the subgroup of non-sepsis patients, ghrelin correlates inversely with renal function and markers of carbohydrate metabolism. High ghrelin levels are an indicator for a favourable prognosis concerning mortality at the ICU in sepsis patients. Furthermore, ghrelin is significantly associated with the necessity of ventilation in critically ill patients. Conclusions Ghrelin serum concentrations are elevated in all circumstances of critical disease, including sepsis and non-sepsis patients. High ghrelin levels are a positive predictor of ICU-survival in sepsis patients, matching previous results from animal models. Future experimental and clinical studies are needed to evaluate ghrelin as a novel prognostic tool in ICU patients and its potential therapeutic use in sepsis.
Collapse
Affiliation(s)
- Alexander Koch
- Department of Medicine III, RWTH-University Hospital Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany.
| | | | | | | | | | | |
Collapse
|
44
|
Andrews ZB, Erion DM, Beiler R, Choi CS, Shulman GI, Horvath TL. Uncoupling protein-2 decreases the lipogenic actions of ghrelin. Endocrinology 2010; 151:2078-86. [PMID: 20189996 PMCID: PMC2869261 DOI: 10.1210/en.2009-0850] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The exact mechanisms through which ghrelin promotes lipogenesis are unknown. Uncoupling protein (UCP)-2 is a mitochondrial protein important in regulating reactive oxygen species; however, recent research shows that it may play an important role fat metabolism. Given that ghrelin increases UCP2 mRNA in white adipose tissue, we examined whether the lipogenic actions of ghrelin are modulated by UCP2 using ucp2(+/+) and ucp2(-/-) mice. Chronic ghrelin treatment either via osmotic minipumps or daily ip injections induced body weight gain in both ucp2(+/+) and ucp2(-/-) mice; however, body weight gain was potentiated in ucp2(-/-) mice. Increased body weight gain was completely due to increased body fat as a result of decreased fat oxidation in ucp2(-/-) mice. Ghrelin treatment of ucp2(-/-) mice resulted in a gene expression profile favoring lipogenesis. In a calorie-restriction model of negative energy balance, ghrelin to ucp2(+/+) mice did not increase body weight; however, ghrelin to ucp2(-/-) mice still induced body weight. These results show that UCP2 plays an important role in fat metabolism by promoting fat oxidation and restricts ghrelin-induced lipogenesis.
Collapse
Affiliation(s)
- Zane B Andrews
- Program on Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA.
| | | | | | | | | | | |
Collapse
|
45
|
Ghrelin in diabetes and metabolic syndrome. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010. [PMID: 20700400 PMCID: PMC2911592 DOI: 10.1155/2010/248948] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 02/09/2010] [Indexed: 02/07/2023]
Abstract
Metabolic syndrome is a cluster of related risk factors for cardiovascular disease, type 2 diabetes and liver disease. Obesity, which has become a global public health problem, is one of the major risk factors for development of metabolic syndrome and type 2 diabetes. Obesity is a complex disease, caused by the interplay between environmental and genetic factors. Ghrelin is one of the circulating peptides, which stimulates appetite and regulates energy balance, and thus is one of the candidate genes for obesity and T2DM. During the last years both basic research and genetic association studies have revealed association between the ghrelin gene and obesity, metabolic syndrome or type 2 diabetes.
Collapse
|
46
|
Metabolic and cardiovascular effects of ghrelin. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010. [PMID: 20798901 PMCID: PMC2925368 DOI: 10.1155/2010/864342] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 01/16/2010] [Indexed: 01/28/2023]
Abstract
Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, is synthesized as a preprohormone and then proteolytically processed to yield a 28-amino acid peptide. This peptide was originally reported to induce growth hormone release; large evidence, however, has indicated many other physiological activities of ghrelin, including regulation of food intake and energy balance, as well as of lipid and glucose metabolism. Ghrelin receptors have been detected in the hypothalamus and the pituitary, but also in the cardiovascular system, where ghrelin exerts beneficial hemodynamic activities. Ghrelin administration acutely improves endothelial dysfunction by increasing nitric oxide bioavailability and normalizes the altered balance between endothelin-1 and nitric oxide within the vasculature of patients with metabolic syndrome. Other cardiovascular effects of ghrelin include improvement of left ventricular contractility and cardiac output, as well as reduction of arterial pressure and systemic vascular resistance. In addition, antinflammatory and antiapoptotic actions of ghrelin have been reported both in vivo and in vitro. This review summarizes the most recent findings on the metabolic and cardiovascular effects of ghrelin through GH-dependent and -independent mechanisms and the possible role of ghrelin as a therapeutic molecule for treating cardiovascular diseases.
Collapse
|
47
|
Abstract
The hormones insulin, leptin, and ghrelin have been demonstrated to act in the central nervous system (CNS) as regulators of energy homeostasis, acting at medial hypothalamic sites. Here, we summarize research demonstrating that, in addition to direct homeostatic actions at the hypothalamus, CNS circuitry that subserves reward and is also a direct and indirect target for the action of these endocrine regulators of energy homeostasis. Specifically, insulin and leptin can decrease food reward behaviors and modulate the function of neurotransmitter systems and neural circuitry that mediate food reward, the midbrain dopamine (DA) and opioidergic pathways. Ghrelin can increase food reward behaviors, and support midbrain DA neuronal function. We summarize discussion of behavioral, systems, and cellular evidence in support of the contributions of reward circuitry to the homeostatic roles of these hormones in the CNS. The understanding of neuroendocrine modulation of food reward, as well as food reward modulation by diet and obesity, may point to new directions for therapeutic approaches to overeating or eating disorders.
Collapse
|
48
|
Effect of ghrelin on glucose-insulin homeostasis: therapeutic implications. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010. [PMID: 20700401 PMCID: PMC2911604 DOI: 10.1155/2010/234709] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 11/23/2009] [Indexed: 12/17/2022]
Abstract
Ghrelin is a 28-amino-acid peptide that displays a strong growth hormone- (GH-) releasing activity through the activation of the growth hormone secretagogue receptor (GHSR). The first studies about role of ghrelin were focused on its orexigenic ability, but despite indisputable pharmacological data, the evidence for a physiological role for ghrelin in the control of appetite is much less clear. Mice with targeted deletion of either ghrelin or the GHSR exhibit an essentially normal metabolic phenotype when fed a regular chow diet, suggesting that ghrelin may have a redundant role in the regulation of food intake. RNAs for ghrelin as well as GHSR are expressed in the pancreas of rats and humans and several studies propose that ghrelin could have an important function in glucose homeostasis and insulin release, independent of GH secretion. Low plasma ghrelin levels are associated with elevated fasting insulin levels and insulin resistance, suggesting both physiological and pathophysiological roles for ghrelin. For this reason, at least theoretically, ghrelin and/or its signalling manipulation could be useful for the treatment or prevention of diseases of glucose homeostasis such as type 2 diabetes.
Collapse
|
49
|
Titterington JS, Sukhanov S, Higashi Y, Vaughn C, Bowers C, Delafontaine P. Growth hormone-releasing peptide-2 suppresses vascular oxidative stress in ApoE-/- mice but does not reduce atherosclerosis. Endocrinology 2009; 150:5478-87. [PMID: 19819949 PMCID: PMC2795722 DOI: 10.1210/en.2009-0283] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
GH-releasing peptide-2 (GHRP-2) is a synthetic peptide that increases circulating GH and IGF-I levels. It also binds to CD36, a scavenger receptor for oxidized low-density lipoprotein (OxLDL), and may prevent cellular uptake of this proatherogenic complex. To determine its potential antiatherogenic effects, GHRP-2 (20 microg twice daily) was administered sc to ApoE(-/-) mice for 12 wk. GHRP-2 increased circulating IGF-I 1.2- to 1.6-fold and decreased circulating interferon-gamma by 66%. Although GHRP-2 did not alter atherosclerotic plaque area, it decreased aortic production of superoxide as assessed by dihydroethidium staining. GHRP-2 decreased aortic gene expression of 12/15-lipoxygenase by 92% and reduced the aortic expression of interferon-gamma and macrophage migration inhibitory factor. In cultured aortic smooth muscle cells, GHRP-2 prevented the OxLDL-induced generation of peroxides, down-regulation of IGF-I receptor, and apoptosis. In macrophages, GHRP-2 reduced lipid accumulation with OxLDL exposure. In summary, GHRP-2 exerts antioxidant effects in vivo and in vitro but does not reduce plaque burden. The lack of an antiatherogenic effect may be due to GH-dependent effects in vivo, thereby blunting the effect of increased IGF-I.
Collapse
Affiliation(s)
- Jane S Titterington
- Section of Endocrinology, Tulane University Heart and Vascular Institute, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
| | | | | | | | | | | |
Collapse
|
50
|
Shah KG, Wu R, Jacob A, Blau SA, Ji Y, Dong W, Marini CP, Ravikumar TS, Coppa GF, Wang P. Human ghrelin ameliorates organ injury and improves survival after radiation injury combined with severe sepsis. Mol Med 2009; 15:407-14. [PMID: 19779631 DOI: 10.2119/molmed.2009.00100] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 09/18/2009] [Indexed: 11/06/2022] Open
Abstract
In the terrorist radiation exposure scenario, radiation victims are likely to suffer from additional injuries such as sepsis. Our previous studies have shown that ghrelin is protective in sepsis. However, it remains unknown whether ghrelin ameliorates sepsis-induced organ injury and mortality after radiation exposure. The purpose of this study is to determine whether human ghrelin attenuates organ injury and improves survival in a rat model of radiation combined injury (RCI) and, if so, the potential mechanism responsible for the benefit. To study this, adult male rats were exposed to 5-Gy whole body irradiation followed by cecal ligation and puncture (CLP, a model of sepsis) 48 h thereafter. Human ghrelin (30 nmol/rat) or vehicle (saline) was infused intravenously via an osmotic minipump immediately after radiation exposure. Blood and tissue samples were collected at 20 h after RCI (68 h after irradiation or 20 h after CLP) for various measurements. To determine the longterm effect of human ghrelin after RCI, the gangrenous cecum was removed at 5 h after CLP and 10-d survival was recorded. In addition, vagotomy or sham vagotomy was performed in sham and RCI animals immediately prior to ghrelin administration, and various measurements were performed at 20 h after RCI. Our results showed that serum levels of ghrelin and its gene expression in the stomach were decreased markedly at 20 h after RCI. Administration of human ghrelin attenuated tissue injury markedly, reduced proinflammatory cytokine levels, decreased tissue myeloperoxidase activity, and improved survival after RCI. Furthermore, elevated plasma levels of norepinephrine (NE) after RCI were reduced significantly by ghrelin. However, vagotomy prevented ghrelin's beneficial effects after RCI. In conclusion, human ghrelin is beneficial in a rat model of RCI. The protective effect of human ghrelin appears to be attributed to re-balancing the dysregulated sympathetic/parasympathetic nervous systems.
Collapse
Affiliation(s)
- Kavin G Shah
- The Feinstein Institute for Medical Research and Department of Surgery, North Shore University Hospital and Long Island Jewish Medical Center, Manhasset, New York 11030, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|