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Nie M, Zhang J, Bal M, Duran C, An SW, Zigman JM, Baum M, Hiremath C, Marciano DK, Wolf MTF. Ghrelin enhances tubular magnesium absorption in the kidney. Front Physiol 2024; 15:1363708. [PMID: 38638279 PMCID: PMC11024433 DOI: 10.3389/fphys.2024.1363708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 03/07/2024] [Indexed: 04/20/2024] Open
Abstract
Osteoporosis after bariatric surgery is an increasing health concern as the rate of bariatric surgery has risen. In animal studies mimicking bariatric procedures, bone disease, together with decreased serum levels of Ca2+, Mg2+ and the gastric hormone Ghrelin were described. Ghrelin regulates metabolism by binding to and activating the growth hormone secretagogue receptor (GHSR) which is also expressed in the kidney. As calcium and magnesium are key components of bone, we tested the hypothesis that Ghrelin-deficiency contributes to osteoporosis via reduced upregulation of the renal calcium channel TRPV5 and the heteromeric magnesium channel TRPM6/7. We expressed GHSR with TRPV5 or TRPM6/7 channel in HEK293 cells and treated them with purified Ghrelin. Whole-cell current density was analyzed by patch-clamp recording. Nephron-specific gene expression was performed by tubular microdissection followed by qPCR in wild-type (WT) mice, and immunofluorescent imaging of GHSR-eGFP mice. Tubular magnesium homeostasis was analyzed in GHSR-null and WT mice at baseline and after caloric restriction. After Ghrelin exposure, whole-cell current density did not change for TRPV5 but increased for TRPM6/7 in a dose-dependent fashion. Applying the Ghrelin-mimetic (D-Trp7, Ala8,D-Phe10)-α-MSH (6-11) amide without and with the GHSR antagonist (D-Lys3)-GHRP6, we confirmed the stimulatory role of Ghrelin towards TRPM6/7. As GHSR initiates downstream signaling via protein kinase A (PKA), we found that the PKA inhibitor H89 abrogated TRPM6/7 stimulation by Ghrelin. Similarly, transfected Gαs, but not the Gαs mutant Q227L, nor Gαi2, Gαq, or Gα13 upregulated TRPM6/7 current density. In microdissected TALs and DCTs similar levels of GHSR mRNA were detected. In contrast, TRPM6 mRNA was expressed in the DCT and also detected in the TAL at 25% expression compared to DCT. Immunofluorescent studies using reporter GHSR-eGFP mice showed a strong eGFP signal in the TAL but surprisingly displayed no eGFP signal in the DCT. In 3-, 6-, and 9-month-old GHSR-null and WT mice, baseline serum magnesium was not significantly different, but 24-h urinary magnesium excretion was elevated in 9-month-old GHSR-null mice. In calorically restricted GHSR-null mice, we detected excess urinary magnesium excretion and reduced serum magnesium levels compared to WT mice. The kidneys from calorically restricted WT mice showed upregulated gene expression of magnesiotropic genes Hnf1b, Cldn-16, Cldn-19, Fxyd-2b, and Parvalbumin compared to GHSR-null mice. Our in vitro studies show that Ghrelin stimulates TRPM6/7 via GHSR and Gαs-PKA signaling. The murine studies are consistent with Ghrelin-GHSR signaling inducing reduced urinary magnesium excretion, particularly in calorically restricted mice when Ghrelin levels are elevated. This effect may be mediated by Ghrelin-upregulation of TRPM6 in the TAL and/or upregulation of other magnesiotropic genes. We postulate that rising Ghrelin levels with hunger contribute to increased renal Mg2+ reabsorption to compensate for lack of enteral Mg2+ uptake.
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Affiliation(s)
- Mingzhu Nie
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Jing Zhang
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Manjot Bal
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Claudia Duran
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Sung Wan An
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Pediatric Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, United States
| | - Jeffrey M. Zigman
- Department of Internal Medicine, Center for Hypothalamic Research, UTSW Medical Center, Dallas, TX, United States
| | - Michel Baum
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Chitkale Hiremath
- Department of Internal Medicine, Nephrology, and Department of Cell Biology, UTSW Medical Center, Dallas, TX, United States
| | - Denise K. Marciano
- Department of Internal Medicine, Nephrology, and Department of Cell Biology, UTSW Medical Center, Dallas, TX, United States
| | - Matthias T. F. Wolf
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Pediatric Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, United States
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Notaro NM, Dyck DJ. Regulation of peripheral tissue substrate metabolism by the gut-derived hormone ghrelin. Metabol Open 2024; 21:100279. [PMID: 38487670 PMCID: PMC10937159 DOI: 10.1016/j.metop.2024.100279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 03/17/2024] Open
Abstract
Ghrelin increases in the circulation prior to entrained mealtimes, with the acylated (AG) form functioning to stimulate food intake and growth hormone release. Acutely, AG induces whole-body insulin resistance, potentially to maintain glycemia between meals. Alternatively, chronic administration of both AG and the unacylated isoform of ghrelin (unAG) is associated with improved skeletal muscle insulin sensitivity as well as reduced intramuscular lipids and inflammation. This may be due to effects on lipid metabolism, with ghrelin promoting storage of fat in adipose and liver while stimulating oxidation in skeletal muscle, preventing ectopic lipid accumulation. This is of specific relevance in the handling of meal-derived lipids, as ghrelin rises preprandially with effects persisting for 2-3 h following exposure in skeletal muscle, coinciding with elevated plasma FFAs. We hypothesize that ghrelin acts as a preparatory signal for incoming lipids, as well as a regulatory hormone for their use and storage. The effects of ghrelin on skeletal muscle are lost with high fat diet feeding and physical inactivity, potentially being implicated in the pathogenesis of metabolic disease. This review summarizes the metabolic effects of both ghrelin isoforms on peripheral tissues including the pancreas, adipose, liver, and skeletal muscle. Additionally, we speculate on the physiological relevance of these effects in vivo and suggest that ghrelin may be a key regulatory hormone for nutrient handling in the postprandial state.
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Affiliation(s)
- Nicole M. Notaro
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - David J. Dyck
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
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Gajewska A, Strzelecki D, Gawlik-Kotelnicka O. Ghrelin as a Biomarker of "Immunometabolic Depression" and Its Connection with Dysbiosis. Nutrients 2023; 15:3960. [PMID: 37764744 PMCID: PMC10537261 DOI: 10.3390/nu15183960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 09/08/2023] [Accepted: 09/10/2023] [Indexed: 09/29/2023] Open
Abstract
Ghrelin, a gastrointestinal peptide, is an endogenous ligand of growth hormone secretagogue receptor 1a (GHSR1a), which is mainly produced by X/A-like cells in the intestinal mucosa. Beyond its initial description as a growth hormone (GH) secretagogue stimulator of appetite, ghrelin has been revealed to have a wide range of physiological effects, for example, the modulation of inflammation; the improvement of cardiac performance; the modulation of stress, anxiety, taste sensation, and reward-seeking behavior; and the regulation of glucose metabolism and thermogenesis. Ghrelin secretion is altered in depressive disorders and metabolic syndrome, which frequently co-occur, but it is still unknown how these modifications relate to the physiopathology of these disorders. This review highlights the increasing amount of research establishing the close relationship between ghrelin, nutrition, microbiota, and disorders such as depression and metabolic syndrome, and it evaluates the ghrelinergic system as a potential target for the development of effective pharmacotherapies.
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Affiliation(s)
- Agata Gajewska
- Faculty of Medicine, Medical University of Lodz, 92-216 Lodz, Poland;
| | - Dominik Strzelecki
- Department of Affective and Psychotic Disorders, Medical University of Lodz, 92-216 Lodz, Poland;
| | - Oliwia Gawlik-Kotelnicka
- Department of Affective and Psychotic Disorders, Medical University of Lodz, 92-216 Lodz, Poland;
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Hoecht EM, Budd JM, Notaro NM, Holloway GP, Dyck DJ. Stimulation of fat oxidation in rat muscle by unacylated ghrelin persists for 2-3 hours, but is independent of fatty acid transporter translocation. Physiol Rep 2023; 11:e15815. [PMID: 37726258 PMCID: PMC10509152 DOI: 10.14814/phy2.15815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/01/2023] [Accepted: 08/11/2023] [Indexed: 09/21/2023] Open
Abstract
While a definitive mechanism-of-action remains to be identified, recent findings indicate that ghrelin, particularly the unacylated form (UnAG), stimulates skeletal muscle fatty acid oxidation. The biological importance of UnAG-mediated increases in fat oxidation remains unclear, as UnAG peaks in the circulation before mealtimes, and decreases rapidly during the postprandial situation before increases in postabsorptive circulating lipids. Therefore, we aimed to determine if the UnAG-mediated stimulation of fat oxidation would persist long enough to affect the oxidation of meal-derived fatty acids, and if UnAG stimulated the translocation of fatty acid transporters to the sarcolemma as a mechanism-of-action. In isolated soleus muscle strips from male rats, short-term pre-treatment with UnAG elicited a persisting stimulus on fatty acid oxidation 2 h after the removal of UnAG. UnAG also caused an immediate phosphorylation of AMPK, but not an increase in plasma membrane FAT/CD36 or FABPpm. There was also no increase in AMPK signaling or increased FAT/CD36 or FABPpm content at the plasma membrane at 2 h which might explain the sustained increase in fatty acid oxidation. These findings confirm UnAG as a stimulator of fatty acid oxidation and provide evidence that UnAG may influence the handling of postprandial lipids. The underlying mechanisms are not known.
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Affiliation(s)
- Evan M. Hoecht
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Joshua M. Budd
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Nicole M. Notaro
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Graham P. Holloway
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - David J. Dyck
- Department of Human Health and Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
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5
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Iwakura H, Ensho T, Ueda Y. Desacyl-ghrelin, not just an inactive form of ghrelin?-A review of current knowledge on the biological actions of desacyl-ghrelin. Peptides 2023:171050. [PMID: 37392995 DOI: 10.1016/j.peptides.2023.171050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/03/2023]
Abstract
Desacyl-ghrelin is a form of ghrelin which lacks acyl-modification of the third serine residue of ghrelin. Originally, desacyl-ghrelin was considered to be just an inactive form of ghrelin. More recently, however, it has been suggested to have various biological activities, including control of food intake, growth hormone, glucose metabolism, and gastric movement, and is involved in cell survival. In this review, we summarize the current knowledge of the biological actions of desacyl-ghrelin and the proposed mechanisms by which it exerts the effects.
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Affiliation(s)
- Hiroshi Iwakura
- Department of Pharmacotherapeutics, School of Pharmaceutical Science, Wakayama Medical University, 25-1 Shichibancho, Wakayama 640-8156, Japan.
| | - Takuya Ensho
- Department of Pharmacotherapeutics, School of Pharmaceutical Science, Wakayama Medical University, 25-1 Shichibancho, Wakayama 640-8156, Japan
| | - Yoko Ueda
- Department of Pharmacotherapeutics, School of Pharmaceutical Science, Wakayama Medical University, 25-1 Shichibancho, Wakayama 640-8156, Japan
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Qian Y, Xia F, Zuo Y, Zhong M, Yang L, Jiang Y, Zou C. Do patients with Prader-Willi syndrome have favorable glucose metabolism? Orphanet J Rare Dis 2022; 17:187. [PMID: 35525976 PMCID: PMC9077846 DOI: 10.1186/s13023-022-02344-3] [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: 01/08/2022] [Accepted: 04/26/2022] [Indexed: 11/26/2022] Open
Abstract
Background In recent years, more studies have observed that patients with Prader–Willi syndrome have lower insulin levels and lower insulin resistance than body mass index-matched controls, which may suggest protected glucose metabolism. Method The PubMed and Web of Science online databases were searched to identify relevant studies published in the English language using the terms “Prader–Willi syndrome” with “glucose”, “insulin”, “diabetes mellitus”, “fat”, “adipo*”, “ghrelin”, “oxytocin”, “irisin” or “autonomic nervous system”. Results The prevalence of impaired glucose intolerance, type 2 diabetes mellitus and some other obesity-associated complications in patients with Prader–Willi syndrome tends to be lower when compared to that in general obesity, which is consistent with the hypothetically protected glucose metabolism. Factors including adipose tissue, adiponectin, ghrelin, oxytocin, irisin, growth hormone and the autonomic nervous system possibly modulate insulin sensitivity in patients with Prader–Willi syndrome. Conclusion Although lower insulin levels, lower IR and protected glucose metabolism are widely reported in PWS patients, the causes are still mysterious. Based on existing knowledge, we cannot determine which factor is of utmost importance and what are the underlying mechanisms, and further research is in urgent need.
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Affiliation(s)
- Yanjie Qian
- Department of Endocrinology, The Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, No 3333 Binsheng Road, Hangzhou, 310051, China
| | - Fangling Xia
- Department of Endocrinology, The Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, No 3333 Binsheng Road, Hangzhou, 310051, China
| | - Yiming Zuo
- Department of Endocrinology, The Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, No 3333 Binsheng Road, Hangzhou, 310051, China
| | - Mianling Zhong
- Department of Endocrinology, The Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, No 3333 Binsheng Road, Hangzhou, 310051, China
| | - Lili Yang
- Department of Endocrinology, The Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, No 3333 Binsheng Road, Hangzhou, 310051, China
| | - Yonghui Jiang
- Department of Genetics, Yale University School of Medicine, New Haven, USA
| | - Chaochun Zou
- Department of Endocrinology, The Children's Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health, No 3333 Binsheng Road, Hangzhou, 310051, China.
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Ghrelin and Cancer: Examining the Roles of the Ghrelin Axis in Tumor Growth and Progression. Biomolecules 2022; 12:biom12040483. [PMID: 35454071 PMCID: PMC9032665 DOI: 10.3390/biom12040483] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 03/16/2022] [Accepted: 03/18/2022] [Indexed: 02/07/2023] Open
Abstract
Ghrelin, a hormone produced and secreted from the stomach, is prim arily known as an appetite stimulant. Recently, it has emerged as a potential regulator/biomarker of cancer progression. Inconsistent results on this subject make this body of literature difficult to interpret. Here, we attempt to identify commonalities in the relationships between ghrelin and various cancers, and summarize important considerations for future research. The main players in the ghrelin family axis are unacylated ghrelin (UAG), acylated ghrelin (AG), the enzyme ghrelin O-acyltransferase (GOAT), and the growth hormone secretagogue receptor (GHSR). GOAT is responsible for the acylation of ghrelin, after which ghrelin can bind to the functional ghrelin receptor GHSR-1a to initiate the activation cascade. Splice variants of ghrelin also exist, with the most prominent being In1-ghrelin. In this review, we focus primarily on the potential of In1-ghrelin as a biomarker for cancer progression, the unique characteristics of UAG and AG, the importance of the two known receptor variants GHSR-1a and 1b, as well as the possible mechanisms through which the ghrelin axis acts. Further understanding of the role of the ghrelin axis in tumor cell proliferation could lead to the development of novel therapeutic approaches for various cancers.
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8
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Zang P, Yang CH, Liu J, Lei HY, Wang W, Guo QY, Lu B, Shao JQ. Relationship Between Acyl and Desacyl Ghrelin Levels with Insulin Resistance and Body Fat Mass in Type 2 Diabetes Mellitus. Diabetes Metab Syndr Obes 2022; 15:2763-2770. [PMID: 36105430 PMCID: PMC9464628 DOI: 10.2147/dmso.s368770] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 08/22/2022] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Although strong evidence suggests that ghrelin plays an important role in regulating energy balance, the effects of acylated ghrelin (AG) and deacylated ghrelin (DAG) on fat mass are largely undefined. This study aimed to investigate the differential associations of both forms of ghrelin with insulin resistance and body fat mass in patients with type 2 diabetes mellitus (T2DM). PATIENTS AND METHODS A total of 162 patients with type 2 diabetes were recruited and classified based on BMI and visceral fat area (VFA) as VFA normal group (n = 78), normal-BMI VFA obesity group (n = 20) and high-BMI VFA obesity group (n = 64). VFA and subcutaneous fat area (SFA) were detected by bioelectrical impedance analysis. Blood samples were collected to measure fasting glucose, insulin, lipids, AG and DAG levels after clinical examination. RESULTS Compared with VFA normal group, DAG levels were significantly lower (421.7 ± 106.0 and 388.7 ± 96.5 pg/mL vs 524.4 ± 141.5 pg/mL, P < 0.01) in the two VFA obesity groups. No significant difference was found in AG levels within three groups. Among all subjects, BMI, VFA, SFA, fasting insulin and HOMA-IR were negatively correlated with DAG but positively with AG/DAG ratio (P < 0.01). In contrast, AG was positively correlated with HOMA-IR and fasting glucose (P < 0.01). Multiple stepwise regression analysis showed that fasting glucose was the independent factor of AG, VFA and HOMA-IR were the independent factors related to DAG. CONCLUSION DAG levels have a strong negative association with excess body fat mass and insulin resistance, whereas AG levels are closely related to elevated blood glucose levels in T2DM patients.
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Affiliation(s)
- Pu Zang
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
| | - Cui-Hua Yang
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
| | - Jun Liu
- Department of Endocrinology, Jinling Hospital, Southern Medical University, Nanjing, People’s Republic of China
| | - Hai-Yan Lei
- Department of Endocrinology, Jinling Hospital, Southern Medical University, Nanjing, People’s Republic of China
| | - Wei Wang
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
| | - Qing-Yu Guo
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
| | - Bin Lu
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
| | - Jia-Qing Shao
- Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China
- Correspondence: Jia-Qing Shao, Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing, People’s Republic of China, Tel +86-25-80860354, Email
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9
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Abstract
Background and Objectives Obesity is the accumulation of adipose tissue caused by excess energy in the body, accompanied by long-term chronic low-grade inflammation of adipose tissue. More than 50% of interstitial cells in adipose tissue are macrophages, which produce cytokines closely related to insulin resistance. Macrophage biology is driven by two polarization phenotypes, M1 (proinflammatory) and M2 (anti-inflammatory). This study aimed to investigate the effect of gastric hormone des-acyl ghrelin (DAG) on the polarization phenotype of macrophages and elucidate the role of macrophages in adipose tissue inflammation and insulin sensitivity and its molecular mechanism. Methods Mice were subcutaneously administrated with DAG in osmotic minipumps. The mice were fed a normal diet or a high-fat diet (HFD). Different macrophage markers were detected by real-time revere transcription polymerase chain reaction. Results Exogenous administration of DAG significantly inhibited the increase of adipocyte volume caused by HFD and reduced the number of rosette-like structures in adipose tissue. HFD in the control group significantly increased M1 macrophage markers, tumor necrosis factor α (TNFα), and inducible NO synthase (iNOS). However, these increases were reduced or even reversed after DAG administration in vitro. The M2 markers, macrophage galactose type C-type Lectin-1 (MGL1), arginase 1 (Arg1), and macrophage mannose receptor 1 (MRC1) were decreased by HFD, and the downward trend was inhibited or reversed after DAG administration. Although Arg1 was elevated after HFD, the fold increase after DAG administration in vitro was much greater than that in the control group. Conclusion DAG inhibits adipose tissue inflammation caused by HFD, reduces infiltration of macrophages in adipose tissue, and promotes polarization of macrophages to M2, thus alleviating obesity and improving insulin sensitivity.
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10
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Wang L, Shi C, Yan H, Xia M, Zhu X, Sun X, Yang X, Jiao H, Wu H, Lou W, Chang X, Gao X, Bian H. Acute Effects of Sleeve Gastrectomy on Glucose Variability, Glucose Metabolism, and Ghrelin Response. Obes Surg 2021; 31:4005-4014. [PMID: 34240316 DOI: 10.1007/s11695-021-05534-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 06/14/2021] [Accepted: 06/17/2021] [Indexed: 02/06/2023]
Abstract
PURPOSE This study aims to examine the changes of glucose metabolism, glucose variability (GV), and ghrelin secretion within 1 week following SG in Chinese patients with obesity. MATERIALS AND METHODS Forty-nine patients with obesity (15 with type 2 diabetes) were enrolled to undergo SG. Within 1 week before and after surgery, liquid meal tests were performed in all subjects, and continuous glucose monitoring (CGM) was performed in diabetic patients. Blood samples were collected at 0, 15, 30, 45, 60, 120, and 180 min for glucose, C-peptide, insulin, and ghrelin analysis in liquid meal test. Mean amplitude of glucose excursions (MAGE), standard deviations (SD), and percent time-in-range (%TIR) determined by CGM were analyzed. RESULTS Both in diabetic and non-diabetic groups, significant decrease was observed in glucose, insulin, C-peptide, and ghrelin. Homeostasis model assessment-insulin resistance and liver fat content was decreased. In diabetic group, MAGE and SD were decreased significantly, and the percent time-in-range was higher. The decrease in blood glucose was positively correlated with the decrease in ghrelin concentration in non-diabetic group. CONCLUSION Within 1 week after SG, both glucose metabolism and glucose variability were improved significantly. Suppression of ghrelin secretion postoperatively might be a driver of this early improved glycemia homeostasis.
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Affiliation(s)
- Liu Wang
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China.,Second Affiliated Hospital of Army Military Medical University, Chongqing, 400037, China
| | - Chenye Shi
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China.,Department of General surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Hongmei Yan
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China
| | - Mingfeng Xia
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China
| | - Xiaopeng Zhu
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China
| | - Xiaoyang Sun
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China
| | - Xinyu Yang
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China
| | - Huan Jiao
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China.,Department of General surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Haifu Wu
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China.,Department of General surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Wenhui Lou
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China.,Department of General surgery, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Xinxia Chang
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China. .,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China.
| | - Xin Gao
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China. .,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China.
| | - Hua Bian
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, 200032, China. .,Fudan Institute for Metabolic Disease, Fudan University, Shanghai, 200032, China. .,Department of Endocrinology and Metabolism, Wusong Branch of Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
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11
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Kim S, Nam Y, Shin SJ, Park YH, Jeon SG, Kim JI, Kim MJ, Moon M. The Potential Roles of Ghrelin in Metabolic Syndrome and Secondary Symptoms of Alzheimer's Disease. Front Neurosci 2020; 14:583097. [PMID: 33071750 PMCID: PMC7543232 DOI: 10.3389/fnins.2020.583097] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022] Open
Abstract
Although the major causative factors of Alzheimer's disease (AD) are the accumulation of amyloid β and hyperphosphorylated tau, AD can also be caused by metabolic dysfunction. The major clinical symptom of AD is cognitive dysfunction. However, AD is also accompanied by various secondary symptoms such as depression, sleep-wake disturbances, and abnormal eating behaviors. Interestingly, the orexigenic hormone ghrelin has been suggested to have beneficial effects on AD-related metabolic syndrome and secondary symptoms. Ghrelin improves lipid distribution and alters insulin sensitivity, effects that are hypothesized to delay the progression of AD. Furthermore, ghrelin can relieve depression by enhancing the secretion of hormones such as serotonin, noradrenaline, and orexin. Moreover, ghrelin can upregulate the expression of neurotrophic factors such as brain-derived neurotrophic factor and modulate the release of proinflammatory cytokines such as tumor necrosis factor α and interleukin 1β. Ghrelin alleviates sleep-wake disturbances by increasing the levels of melatonin, melanin-concentrating hormone. Ghrelin reduces the risk of abnormal eating behaviors by increasing neuropeptide Y and γ-aminobutyric acid. In addition, ghrelin increases food intake by inhibiting fatty acid biosynthesis. However, despite the numerous studies on the role of ghrelin in the AD-related pathology and metabolic disorders, there are only a few studies that investigate the effects of ghrelin on secondary symptoms associated with AD. In this mini review, our purpose is to provide the insights of future study by organizing the previous studies for the role of ghrelin in AD-related pathology and metabolic disorders.
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Affiliation(s)
- Sujin Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Yunkwon Nam
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Soo Jung Shin
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Yong Ho Park
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Seong Gak Jeon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea.,Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Jin-Il Kim
- Department of Nursing, College of Nursing, Jeju National University, Jeju-si, South Korea
| | - Min-Jeong Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Minho Moon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
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12
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Au CC, Furness JB, Britt K, Oshchepkova S, Ladumor H, Soo KY, Callaghan B, Gerard C, Inghirami G, Mittal V, Wang Y, Huang XY, Spector JA, Andreopoulou E, Zumbo P, Betel D, Dow L, Brown KA. Three-dimensional growth of breast cancer cells potentiates the anti-tumor effects of unacylated ghrelin and AZP-531. eLife 2020; 9:56913. [PMID: 32667883 PMCID: PMC7363447 DOI: 10.7554/elife.56913] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/25/2020] [Indexed: 12/31/2022] Open
Abstract
Breast cancer is the most common type of cancer in women and notwithstanding important therapeutic advances, remains the second leading cause of cancer-related death. Despite extensive research relating to the hormone ghrelin, responsible for the stimulation of growth hormone release and appetite, little is known of the effects of its unacylated form, especially in cancer. The present study aimed to characterize effects of unacylated ghrelin on breast cancer cells, define its mechanism of action, and explore the therapeutic potential of unacylated ghrelin or analog AZP-531. We report potent anti-tumor effects of unacylated ghrelin, dependent on cells being cultured in 3D in a biologically-relevant extracellular matrix. The mechanism of unacylated ghrelin-mediated growth inhibition involves activation of Gαi and suppression of MAPK signaling. AZP-531 also suppresses the growth of breast cancer cells in vitro and in xenografts, and may be a novel approach for the safe and effective treatment of breast cancer.
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Affiliation(s)
- CheukMan C Au
- Department of Medicine, Weill Cornell Medicine, New York, United States.,Centre for Cancer Research, Hudson Institute for Medical Research, Clayton, Australia.,Department of Molecular and Translational Sciences, Monash University, Clayton, Australia
| | - John B Furness
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Australia
| | - Kara Britt
- Peter MacCallum Cancer Centre, Melbourne, Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia
| | - Sofya Oshchepkova
- Department of Medicine, Weill Cornell Medicine, New York, United States
| | - Heta Ladumor
- Department of Medicine, Weill Cornell Medicine, New York, United States.,Weill Cornell Medicine - Qatar, Doha, Qatar
| | - Kai Ying Soo
- Centre for Cancer Research, Hudson Institute for Medical Research, Clayton, Australia
| | - Brid Callaghan
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Australia
| | - Celine Gerard
- Centre for Cancer Research, Hudson Institute for Medical Research, Clayton, Australia
| | - Giorgio Inghirami
- Department of Pathology, Weill Cornell Medical College, New York, United States
| | - Vivek Mittal
- Department of Cardiothoracic Surgery, Department of Cell and Developmental Biology, Neuberger Berman Lung Cancer Center, Weill Cornell Medicine, New York, United States
| | - Yufeng Wang
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, United States
| | - Xin Yun Huang
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, United States
| | - Jason A Spector
- Department of Surgery, Weill Cornell Medicine, New York, United States
| | | | - Paul Zumbo
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, United States.,Applied Bioinformatics Core, Weill Cornell Medical College, New York, United States
| | - Doron Betel
- Department of Medicine, Weill Cornell Medicine, New York, United States.,Institute for Computational Biomedicine, Weill Cornell Medical College, New York, United States
| | - Lukas Dow
- Department of Medicine, Weill Cornell Medicine, New York, United States
| | - Kristy A Brown
- Department of Medicine, Weill Cornell Medicine, New York, United States.,Centre for Cancer Research, Hudson Institute for Medical Research, Clayton, Australia.,Department of Molecular and Translational Sciences, Monash University, Clayton, Australia
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13
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Barazzoni R, Gortan Cappellari G, Zanetti M, Klaus KA, Semolic A, Johnson ML, Nair KS. Higher unacylated ghrelin and insulin sensitivity following dietary restriction and weight loss in obese humans. Clin Nutr 2020; 40:638-644. [PMID: 32641220 DOI: 10.1016/j.clnu.2020.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 05/27/2020] [Accepted: 06/15/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND & AIMS Unacylated ghrelin (UnAG) modulates insulin sensitivity. Low plasma UnAG occurs in obesity and potentially contributes to obesity-associated insulin resistance. We hypothesized that improvements in insulin sensitivity in obese people induced by moderate caloric restriction (CR) may be paralleled and at least in part explained by concurrent increases in UnAG levels. METHODS 20 general community obese people were randomly assigned to 16-week CR (n = 11) or control diet (n = 9). We investigated the impact of CR on the interaction between insulin sensitivity changes [area under the curve (AUCg) of glucose infusion to maintain euglycemia during hyperinsulinemic-euglycemic clamp] and plasma total (TotalG), acylated (AG) and Unacylated ghrelin (UnAG). Plasma pro-inflammatory tumor necrosis factor alpha (TNFα) and anti-inflammatory interleukin-10 (IL-10) were also measured since changes in inflammation may contribute to UnAG activities. RESULTS CR reduced BMI and increased insulin sensitivity (p < 0.05). TotalG and UnAG but not AG increased in CR but not in Control (p < 0.05). Il-10 and IL-10/TNFα ratio also increased in CR (p < 0.05). Changes in UnAG were positively associated with changes in AUCg in all subjects (n = 20; p < 0.01) also after adjustment for treatment and changes in BMI and cytokines. CONCLUSIONS Caloric restriction modifies circulating ghrelin profile with selective increase in unacylated hormone in obese individuals. The current study supports the hypothesis that higher unacylated ghrelin contributes to improvements in insulin sensitivity following diet-induced weight loss in human obesity.
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Affiliation(s)
- Rocco Barazzoni
- Dept. of Medical, Surgical and Health Sciences - University of Trieste, Italy and Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Trieste, Italy.
| | - Gianluca Gortan Cappellari
- Dept. of Medical, Surgical and Health Sciences - University of Trieste, Italy and Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Trieste, Italy
| | - Michela Zanetti
- Dept. of Medical, Surgical and Health Sciences - University of Trieste, Italy and Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Trieste, Italy
| | - Katherine A Klaus
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN, USA
| | - Annamaria Semolic
- Dept. of Medical, Surgical and Health Sciences - University of Trieste, Italy and Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Trieste, Italy
| | - Matthew L Johnson
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN, USA
| | - K Sreekumaran Nair
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN, USA.
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14
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Jeon SG, Hong SB, Nam Y, Tae J, Yoo A, Song EJ, Kim KI, Lee D, Park J, Lee SM, Kim JI, Moon M. Ghrelin in Alzheimer's disease: Pathologic roles and therapeutic implications. Ageing Res Rev 2019; 55:100945. [PMID: 31434007 DOI: 10.1016/j.arr.2019.100945] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/25/2019] [Accepted: 08/16/2019] [Indexed: 12/11/2022]
Abstract
Ghrelin, which has many important physiological roles, such as stimulating food intake, regulating energy homeostasis, and releasing insulin, has recently been studied for its roles in a diverse range of neurological disorders. Despite the several functions of ghrelin in the central nervous system, whether it works as a therapeutic agent for neurological dysfunction has been unclear. Altered levels and various roles of ghrelin have been reported in Alzheimer's disease (AD), which is characterized by the accumulation of misfolded proteins resulting in synaptic loss and cognitive decline. Interestingly, treatment with ghrelin or with the agonist of ghrelin receptor showed attenuation in several cases of AD-related pathology. These findings suggest the potential therapeutic implications of ghrelin in the pathogenesis of AD. In the present review, we summarized the roles of ghrelin in AD pathogenesis, amyloid beta (Aβ) homeostasis, tau hyperphosphorylation, neuroinflammation, mitochondrial deficit, synaptic dysfunction and cognitive impairment. The findings from this review suggest that ghrelin has a novel therapeutic potential for AD treatment. Thus, rigorously designed studies are needed to establish an effective AD-modifying strategy.
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15
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Kokkinos A, Tsilingiris D, le Roux CW, Rubino F, Mantzoros CS. Will medications that mimic gut hormones or target their receptors eventually replace bariatric surgery? Metabolism 2019; 100:153960. [PMID: 31412266 DOI: 10.1016/j.metabol.2019.153960] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/31/2019] [Accepted: 08/05/2019] [Indexed: 02/07/2023]
Abstract
Bariatric surgery is currently the most effective therapeutic modality through which sustained beneficial effects on weight loss and metabolic improvement are achieved. During recent years, indications for bariatric surgery have been expanded to include cases of poorly controlled type 2 (T2DM) diabetes mellitus in lesser extremes of body weight. A spectrum of the beneficial effects of surgery is attributed to robust changes of postprandial gut peptide responses that are observed post operatively. Consolidated knowledge regarding gut peptide physiology as well as emerging new evidence shedding light on the mode of action of previously overlooked gut hormones provide appealing potential obesity and T2DM therapeutic perspectives. The accumulation of evidence from the effect of exogenous administration of native gut peptides alone or in combinations to humans as well as the development of mimetic agents exerting agonistic effects on combinations of gut hormone receptors pave the way for future integrated gut peptide-based treatments, which may mimic the effects of bariatric surgery.
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Affiliation(s)
- Alexander Kokkinos
- First Department of Propaedeutic Internal Medicine, Medical School, National and Kapodistrian University of Athens, Laiko General Hospital, Athens, Greece.
| | - Dimitrios Tsilingiris
- First Department of Propaedeutic Internal Medicine, Medical School, National and Kapodistrian University of Athens, Laiko General Hospital, Athens, Greece
| | - Carel W le Roux
- Diabetes Complications Research Centre, University College Dublin, Dublin, Ireland
| | - Francesco Rubino
- Department of Metabolic and Bariatric Surgery, Diabetes and Nutritional Science Division, King's College Hospital, London, United Kingdom
| | - Christos S Mantzoros
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, USA
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16
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Gray SM, Niu J, Zhang A, Svendsen B, Campbell JE, D'Alessio DA, Tong J. Intraislet Ghrelin Signaling Does Not Regulate Insulin Secretion From Adult Mice. Diabetes 2019; 68:1795-1805. [PMID: 31201280 PMCID: PMC6702634 DOI: 10.2337/db19-0079] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 06/06/2019] [Indexed: 01/08/2023]
Abstract
Exogenous ghrelin reduces glucose-stimulated insulin secretion and endogenous ghrelin protects against hypoglycemia during starvation. Islet ε-cells produce ghrelin and δ-cells express growth hormone secretagogue receptor (GHSR), suggesting the possibility of a paracrine mechanism for islet ghrelin to reach high local concentrations and affect insulin secretion. GHSR has high constitutive activity and may act independently of ghrelin. The objective in this study was to determine whether an intraislet ghrelin-GHSR axis modulates insulin secretion and glucose metabolism using mouse models lacking ghrelin (Ghrl-/- ) or GHSR (Ghsr-/- ). Ghsr-/- and Ghsr+/+ mice had comparable islet ghrelin concentrations. Exogenous ghrelin decreased insulin secretion in perifused isolated islets in a GHSR-dependent manner. Islets isolated from Ghrl-/- or Ghsr-/- mice did not differ from controls in glucose-, alanine-, or GLP-1-stimulated insulin secretion during perifusion. Consistent with this finding, Ghrl-/- and Ghsr-/- male mice studied after either 6 or 16 h of fasting had blood glucose concentrations comparable with those of controls following intraperitoneal glucose, or insulin tolerance tests, or after mixed nutrient meals. Collectively, our data provide strong evidence against a paracrine ghrelin-GHSR axis mediating insulin secretion or glucose tolerance in lean, chow-fed adult mice.
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Affiliation(s)
| | | | | | | | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Durham, NC
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - David A D'Alessio
- Duke Molecular Physiology Institute, Durham, NC
- Division of Endocrinology, Metabolism, and Nutrition, Department of Medicine, Duke University, Durham, NC
| | - Jenny Tong
- Duke Molecular Physiology Institute, Durham, NC
- Division of Endocrinology, Metabolism, and Nutrition, Department of Medicine, Duke University, Durham, NC
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17
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Gray SM, Page LC, Tong J. Ghrelin regulation of glucose metabolism. J Neuroendocrinol 2019; 31:e12705. [PMID: 30849212 PMCID: PMC6688917 DOI: 10.1111/jne.12705] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 12/14/2022]
Abstract
Ghrelin and its receptor, the growth hormone secretagogue receptor 1a (GHSR1a), are implicated in the regulation of glucose metabolism via direct actions in the pancreatic islet, as well as peripheral insulin-sensitive tissues and the brain. Although many studies have explored the role of ghrelin in glucose tolerance and insulin secretion, a complete mechanistic understanding remains to be clarified. This review highlights the local expression and function of ghrelin and GHSR1a in pancreatic islets and how this axis may modulate insulin secretion from pancreatic β-cells. Additionally, we discuss the effect of ghrelin on in vivo glucose metabolism in rodents and humans, as well as the metabolic circumstances under which the action of ghrelin may predominate.
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Affiliation(s)
- Sarah. M. Gray
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701
| | - Laura C. Page
- Division of Endocrinology, Department of Pediatrics, Duke University, Durham, NC 27701
| | - Jenny Tong
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701
- Division of Endocrinology, Department of Pediatrics, Duke University, Durham, NC 27701
- Division of Endocrinology, Metabolism, and Nutrition, Department of Medicine, Duke University, Durham, NC 27701
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18
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Mani BK, Shankar K, Zigman JM. Ghrelin's Relationship to Blood Glucose. Endocrinology 2019; 160:1247-1261. [PMID: 30874792 PMCID: PMC6482034 DOI: 10.1210/en.2019-00074] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 03/09/2019] [Indexed: 12/16/2022]
Abstract
Much effort has been directed at studying the orexigenic actions of administered ghrelin and the potential effects of the endogenous ghrelin system on food intake, food reward, body weight, adiposity, and energy expenditure. Although endogenous ghrelin's actions on some of these processes remain ambiguous, its glucoregulatory actions have emerged as well-recognized features during extreme metabolic conditions. The blood glucose-raising actions of ghrelin are beneficial during starvation-like conditions, defending against life-threatening falls in blood glucose, but they are seemingly detrimental in obese states and in certain monogenic forms of diabetes, contributing to hyperglycemia. Also of interest, blood glucose negatively regulates ghrelin secretion. This article reviews the literature suggesting the existence of a blood glucose-ghrelin axis and highlights the factors that mediate the glucoregulatory actions of ghrelin, especially during metabolic extremes such as starvation and diabetes.
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Affiliation(s)
- Bharath K Mani
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Kripa Shankar
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jeffrey M Zigman
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
- Correspondence: Jeffrey M. Zigman, MD, PhD, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390. E-mail:
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19
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Churm R, Caplin S, Barry J, Davies JS, Stephens JW, Prior SL. Acyl-ghrelin mediated lipid retention and inflammation in obesity-related Type 2 diabetes. Mol Cell Endocrinol 2019; 481:8-13. [PMID: 30439508 DOI: 10.1016/j.mce.2018.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/10/2018] [Accepted: 11/12/2018] [Indexed: 12/28/2022]
Abstract
Acyl-ghrelin has various peripheral effects including the potential role in mediating cellular lipid removal and macrophage polarization. Previous reports are contradictory as to how glycaemia and acyl-ghrelin mediates lipid retention and inflammation within individuals with Type 2 diabetes (T2D). Our aim was to explore acyl-ghrelin levels and ghrelin expression in relation to lipid and inflammatory markers within an ex vivo human model, biopsied visceral adipose tissue. Results indicated that acyl-ghrelin was associated with a decline in key lipid homeostasis genes ABCG1 and LXRβ expression. Within T2D there was also a down regulation of these genes which was independent of acyl-ghrelin levels. Circulatory pro-inflammatory markers (IL-6 and TNFα) had no association with ghrelin expression nor circulating acyl-ghrelin levels. Anti-inflammatory marker (IL-10) and total antioxidant status (TAOS%) were positively associated with ghrelin expression across samples from all groups combined (total sample cohort) and specifically within the obesity sample cohorts. Data supported the hypothesis that hyperglycaemia and acyl-ghrelin have a regulatory role in lipid retention. Furthermore, that both acyl- and desacyl-ghrelin is responsible for a protective inflammatory response; however this response is diminished in T2D.
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Affiliation(s)
- R Churm
- Diabetes Research Group, Grove Building, Swansea University, Swansea, UK.
| | - S Caplin
- Welsh Institute of Metabolic & Obesity Surgery, Morriston Hospital, Swansea, UK
| | - J Barry
- Welsh Institute of Metabolic & Obesity Surgery, Morriston Hospital, Swansea, UK
| | - J S Davies
- Molecular Neurobiology Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| | - J W Stephens
- Diabetes Research Group, Grove Building, Swansea University, Swansea, UK
| | - S L Prior
- Diabetes Research Group, Grove Building, Swansea University, Swansea, UK
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20
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Maugham ML, Seim I, Thomas PB, Crisp GJ, Shah ET, Herington AC, Brown KA, Gregory LS, Nelson CC, Jeffery PL, Chopin LK. No effect of unacylated ghrelin administration on subcutaneous PC3 xenograft growth or metabolic parameters in a Rag1-/- mouse model of metabolic dysfunction. PLoS One 2018; 13:e0198495. [PMID: 30458004 PMCID: PMC6245673 DOI: 10.1371/journal.pone.0198495] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 11/02/2018] [Indexed: 12/12/2022] Open
Abstract
Ghrelin is a peptide hormone which, when acylated, regulates appetite, energy balance and a range of other biological processes. Ghrelin predominately circulates in its unacylated form (unacylated ghrelin; UAG). UAG has a number of functions independent of acylated ghrelin, including modulation of metabolic parameters and cancer progression. UAG has also been postulated to antagonise some of the metabolic effects of acyl-ghrelin, including its effects on glucose and insulin regulation. In this study, Rag1-/- mice with high-fat diet-induced obesity and hyperinsulinaemia were subcutaneously implanted with PC3 prostate cancer xenografts to investigate the effect of UAG treatment on metabolic parameters and xenograft growth. Daily intraperitoneal injection of 100 μg/kg UAG had no effect on xenograft tumour growth in mice fed normal rodent chow or 23% high-fat diet. UAG significantly improved glucose tolerance in host Rag1-/- mice on a high-fat diet, but did not significantly improve other metabolic parameters. We propose that UAG is not likely to be an effective treatment for prostate cancer, with or without associated metabolic syndrome.
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Affiliation(s)
- Michelle L. Maugham
- Ghrelin Research Group, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Australian Prostate Cancer Research Centre - Queensland, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Comparative and Endocrine Biology Laboratory, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Skeletal Biology and Forensic Anthropology Research Laboratory, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Inge Seim
- Ghrelin Research Group, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Australian Prostate Cancer Research Centre - Queensland, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Comparative and Endocrine Biology Laboratory, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Patrick B. Thomas
- Ghrelin Research Group, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Australian Prostate Cancer Research Centre - Queensland, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Comparative and Endocrine Biology Laboratory, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Gabrielle J. Crisp
- Ghrelin Research Group, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Australian Prostate Cancer Research Centre - Queensland, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Comparative and Endocrine Biology Laboratory, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Esha T. Shah
- Ghrelin Research Group, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Australian Prostate Cancer Research Centre - Queensland, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Comparative and Endocrine Biology Laboratory, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Adrian C. Herington
- Ghrelin Research Group, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Australian Prostate Cancer Research Centre - Queensland, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kristy A. Brown
- Department of Medicine, Weill Cornell Medicine, New York City, New York, United States of America
| | - Laura S. Gregory
- Skeletal Biology and Forensic Anthropology Research Laboratory, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Colleen C. Nelson
- Australian Prostate Cancer Research Centre - Queensland, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Penny L. Jeffery
- Ghrelin Research Group, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Australian Prostate Cancer Research Centre - Queensland, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Comparative and Endocrine Biology Laboratory, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Lisa K. Chopin
- Ghrelin Research Group, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Australian Prostate Cancer Research Centre - Queensland, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- Comparative and Endocrine Biology Laboratory, Translational Research Institute – Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
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21
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Cleverdon ER, McGovern-Gooch KR, Hougland JL. The octanoylated energy regulating hormone ghrelin: An expanded view of ghrelin's biological interactions and avenues for controlling ghrelin signaling. Mol Membr Biol 2017; 33:111-124. [PMID: 29143554 DOI: 10.1080/09687688.2017.1388930] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ghrelin is a small peptide hormone that requires a unique post-translational modification, serine octanoylation, to bind and activate the GHS-R1a receptor. Initially demonstrated to stimulate hunger and appetite, ghrelin-dependent signaling is implicated in a variety of neurological and physiological processes influencing diseases such as diabetes, obesity, and Prader-Willi syndrome. In addition to its cognate receptor, recent studies have revealed ghrelin interacts with a range of binding partners within the bloodstream. Defining the scope of ghrelin's interactions within the body, understanding how these interactions work in concert to modulate ghrelin signaling, and developing molecular tools for controlling ghrelin signaling are essential for exploiting ghrelin for therapeutic effect. In this review, we discuss recent findings regarding the biological effects of ghrelin signaling, outline binding partners that control ghrelin trafficking and stability in circulation, and summarize the current landscape of inhibitors targeting ghrelin octanoylation.
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Affiliation(s)
| | | | - James L Hougland
- a Department of Chemistry , Syracuse University , Syracuse , NY , USA
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22
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Chen VP, Gao Y, Geng L, Brimijoin S. Butyrylcholinesterase gene transfer in obese mice prevents postdieting body weight rebound by suppressing ghrelin signaling. Proc Natl Acad Sci U S A 2017; 114:10960-10965. [PMID: 28973869 PMCID: PMC5642694 DOI: 10.1073/pnas.1706517114] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The worldwide prevalence of obesity is increasing at an alarming rate but treatment options remain limited. Despite initial success, weight loss by calorie restriction (CR) often fails because of rebound weight gain. Postdieting hyperphagia along with altered hypothalamic neuro-architecture appears to be one direct cause of this undesirable outcome. In response to calorie deficiency the circulating levels of the appetite-promoting hormone, acyl-ghrelin, rise sharply. We hypothesize that proper modulation of acyl-ghrelin and its receptor's sensitivity will favorably impact energy intake and reprogram the body weight set point. Here we applied viral gene transfer of the acyl-ghrelin hydrolyzing enzyme, butyrylcholinesterase (BChE), in a mouse model of diet-induced obesity. Our results confirmed that BChE overexpression decreased circulating acyl-ghrelin levels, suppressed CR-provoked ghrelin signaling, and restored central ghrelin sensitivity. In addition to maintaining healthy body weights, BChE treated mice had modest postdieting food intake and showed normal glucose homeostasis. Spontaneous activity and energy expenditure did not differ significantly between treated and untreated mice after body weight rebound, suggesting that BChE gene transfer did not alter energy expenditure in the long term. These findings indicate that combining BChE treatment with CR could be an effective approach in treating human obesity and aiding lifelong weight management.
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Affiliation(s)
- Vicky Ping Chen
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905
| | - Yang Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905
| | - Liyi Geng
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905
| | - Stephen Brimijoin
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905
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23
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Central Modulation of Neuroinflammation by Neuropeptides and Energy-Sensing Hormones during Obesity. BIOMED RESEARCH INTERNATIONAL 2017; 2017:7949582. [PMID: 28913358 PMCID: PMC5587954 DOI: 10.1155/2017/7949582] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/19/2017] [Accepted: 07/24/2017] [Indexed: 02/06/2023]
Abstract
Central nervous system (CNS) senses energy homeostasis by integrating both peripheral and autonomic signals and responding to them by neurotransmitters and neuropeptides release. Although it is previously considered an immunologically privileged organ, we now know that this is not so. Cells belonging to the immune system, such as B and T lymphocytes, can be recruited into the CNS to face damage or infection, in addition to possessing resident immunological cells, called microglia. In this way, positive energy balance during obesity promotes an inflammatory state in the CNS. Saturated fatty acids from the diet have been pointed out as powerful candidates to trigger immune response in peripheral system and in the CNS. However, how central immunity communicates to peripheral immune response remains to be clarified. Recently there has been a great interest in the neuropeptides, POMC derived peptides, ghrelin, and leptin, due to their capacity to suppress or induce inflammatory responses in the brain, respectively. These may be potential candidates to treat different pathologies associated with autoimmunity and inflammation. In this review, we will discuss the role of lipotoxicity associated with positive energy balance during obesity in proinflammatory response in microglia, B and T lymphocytes, and its modulation by neuropeptides.
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24
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Reano S, Angelino E, Ferrara M, Malacarne V, Sustova H, Sabry O, Agosti E, Clerici S, Ruozi G, Zentilin L, Prodam F, Geuna S, Giacca M, Graziani A, Filigheddu N. Unacylated Ghrelin Enhances Satellite Cell Function and Relieves the Dystrophic Phenotype in Duchenne Muscular Dystrophy mdx Model. Stem Cells 2017; 35:1733-1746. [PMID: 28436144 DOI: 10.1002/stem.2632] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 02/28/2017] [Accepted: 04/06/2017] [Indexed: 12/17/2022]
Abstract
Muscle regeneration depends on satellite cells (SCs), quiescent precursors that, in consequence of injury or in pathological states such as muscular dystrophies, activate, proliferate, and differentiate to repair the damaged tissue. A subset of SCs undergoes self-renewal, thus preserving the SC pool and its regenerative potential. Unacylated ghrelin (UnAG) is a circulating hormone that protects muscle from atrophy, promotes myoblast differentiation, and enhances ischemia-induced muscle regeneration. Here we show that UnAG increases SC activity and stimulates Par polarity complex/p38-mediated asymmetric division, fostering both SC self-renewal and myoblast differentiation. Because of those activities on different steps of muscle regeneration, we hypothesized a beneficial effect of UnAG in mdx dystrophic mice, in which the absence of dystrophin leads to chronic muscle degeneration, defective muscle regeneration, fibrosis, and, at later stages of the pathology, SC pool exhaustion. Upregulation of UnAG levels in mdx mice reduces muscle degeneration, improves muscle function, and increases dystrophin-null SC self-renewal, maintaining the SC pool. Our results suggest that UnAG has significant therapeutic potential for preserving the muscles in dystrophies. Stem Cells 2017;35:1733-1746.
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Affiliation(s)
- Simone Reano
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy and Istituto Interuniversitario di Miologia (IIM)
| | - Elia Angelino
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy and Istituto Interuniversitario di Miologia (IIM)
| | - Michele Ferrara
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy and Istituto Interuniversitario di Miologia (IIM)
| | - Valeria Malacarne
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy and Istituto Interuniversitario di Miologia (IIM)
| | - Hana Sustova
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy and Istituto Interuniversitario di Miologia (IIM)
| | - Omar Sabry
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy and Istituto Interuniversitario di Miologia (IIM)
| | - Emanuela Agosti
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy and Istituto Interuniversitario di Miologia (IIM)
| | - Sara Clerici
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy and Istituto Interuniversitario di Miologia (IIM)
| | - Giulia Ruozi
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Lorena Zentilin
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Flavia Prodam
- Department of Health Sciences, University of Piemonte Orientale, Novara, Italy
| | - Stefano Geuna
- Department of Clinical and Biological Sciences, University of Torino and Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano (TO), Italy
| | - Mauro Giacca
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Andrea Graziani
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy and Istituto Interuniversitario di Miologia (IIM)
| | - Nicoletta Filigheddu
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy and Istituto Interuniversitario di Miologia (IIM)
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25
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Labarthe A, Tolle V. [Ghrelin: a gastric hormone at the crossroad between growth and appetite regulation]. Biol Aujourdhui 2017; 210:237-257. [PMID: 28327282 DOI: 10.1051/jbio/2016027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Indexed: 06/06/2023]
Abstract
Ghrelin is a 28 amino acid peptide hormone synthesized within the gastrointestinal tract. Initially identified as the endogenous ligand of the GHS-R1a (Growth Hormone Secretagogue Receptor 1a), ghrelin is a powerful stimulator of growth hormone (GH) secretion. At the crossroad between nutrition, growth and long-term energy metabolism, ghrelin also plays a unique role as the first identified gastric hormone increasing appetite and adiposity. However, the role of the ghrelin/GHS-R system in the physiology of growth, feeding behaviour and energy homeostasis needs to be better understood. Utilization of pharmacological tools and complementary animal models with deficiency in preproghrelin, ghrelin-O-acyl-transferase (GOAT - the enzyme that acylates ghrelin -) or GHS-R in situations of chronic undernutrition or high fat diet gives a more precise overview of the role of ghrelin in the pathophysiology of eating and metabolic disorders.
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26
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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.
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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
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27
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Zhang CJ, Bidlingmaier M, Altaye M, Page LC, D'Alessio D, Tschöp MH, Tong J. Acute administration of acyl, but not desacyl ghrelin, decreases blood pressure in healthy humans. Eur J Endocrinol 2017; 176:123-132. [PMID: 27913606 PMCID: PMC5325691 DOI: 10.1530/eje-16-0789] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/02/2016] [Accepted: 11/08/2016] [Indexed: 01/13/2023]
Abstract
OBJECTIVE To compare the effects of acyl ghrelin (AG) and desacyl ghrelin (DAG) on blood pressure (BP), heart rate (HR) and other autonomic parameters in healthy humans and to elucidate the hormonal mechanisms through which AG could exert its cardiovascular effects. DESIGN Seventeen healthy participants underwent frequent monitoring of systolic (sBP) and diastolic blood pressure (dBP), HR, respiratory rate (RR) and body surface temperature (Temp) during continuous infusion of AG, DAG, combined AG + DAG or saline control before and during an IV glucose tolerance test on 4 separate days. Plasma catecholamines, renin and aldosterone levels were also measured. Differences in outcome measures between treatment groups were assessed using mixed-model analysis. RESULTS Compared to the saline control, AG and combined AG + DAG infusions decreased sBP, dBP, mean arterial blood pressure (MAP), HR and Temp. In contrast, DAG infusion did not alter BP, RR or Temp, but did decrease HR. The AG and AG + DAG infusions also raised plasma aldosterone levels compared to saline (P < 0.001) without affecting renin or catecholamine levels. CONCLUSIONS The decrease in BP, HR, RR and Temp with AG infusion suggests mediation through the autonomic nervous system. The lack of response to DAG suggests that these autonomic effects require activation of the ghrelin receptor.
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Affiliation(s)
- Cecilia J Zhang
- Division of EndocrinologyMetabolism and Nutrition, Department of Medicine, Duke University, Durham, North Carolina, USA
| | - Martin Bidlingmaier
- Medizinische Klinik und Poliklinik IVLudwig-Maximilians-Universität, Munich, Germany
| | - Mekibib Altaye
- BiostatisticsClinical Translational Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Laura C Page
- Division of Pediatric Endocrinology and DiabetesDepartment of Pediatrics, Duke University, Durham, North Carolina, USA
| | - David D'Alessio
- Division of EndocrinologyDiabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
- Division of EndocrinologyMetabolism and Nutrition, Department of Medicine, Duke University, Durham, North Carolina, USA
- Cincinnati Veterans Affairs Medical CenterCincinnati, Ohio, USA
| | - Matthias H Tschöp
- Division of EndocrinologyDiabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
- Institute for Obesity and DiabetesHelmholtz Diabetes Center Munich and Division of Metabolic Diseases, Technical University, Munich, Germany
| | - Jenny Tong
- Division of EndocrinologyDiabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
- Division of EndocrinologyMetabolism and Nutrition, Department of Medicine, Duke University, Durham, North Carolina, USA
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28
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Churm R, Davies JS, Stephens JW, Prior SL. Ghrelin function in human obesity and type 2 diabetes: a concise review. Obes Rev 2017; 18:140-148. [PMID: 27899023 DOI: 10.1111/obr.12474] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/06/2016] [Accepted: 09/06/2016] [Indexed: 12/12/2022]
Abstract
The 28 amino acid hormone, ghrelin, has been found to have various effects on metabolism. This review will focus on the pathways integrated into ghrelin's effect within the hypothalamus, pancreas and adipocytes. The identification of molecules and pathways that regulate ghrelin-mediated lipid retention could establish new mechanisms underlying cellular energy homeostasis. The impact of acyl-ghrelin on glucose metabolism and lipid homeostasis may allow for novel preventative or early intervention therapeutic strategies to treat obesity related type 2 diabetes and associated metabolic dysfunction.
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Affiliation(s)
- R Churm
- Diabetes Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| | - J S Davies
- Molecular Neurobiology Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| | - J W Stephens
- Diabetes Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| | - S L Prior
- Diabetes Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
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29
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From Belly to Brain: Targeting the Ghrelin Receptor in Appetite and Food Intake Regulation. Int J Mol Sci 2017; 18:ijms18020273. [PMID: 28134808 PMCID: PMC5343809 DOI: 10.3390/ijms18020273] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 01/19/2017] [Indexed: 12/20/2022] Open
Abstract
Ghrelin is the only known peripherally-derived orexigenic hormone, increasing appetite and subsequent food intake. The ghrelinergic system has therefore received considerable attention as a therapeutic target to reduce appetite in obesity as well as to stimulate food intake in conditions of anorexia, malnutrition and cachexia. As the therapeutic potential of targeting this hormone becomes clearer, it is apparent that its pleiotropic actions span both the central nervous system and peripheral organs. Despite a wealth of research, a therapeutic compound specifically targeting the ghrelin system for appetite modulation remains elusive although some promising effects on metabolic function are emerging. This is due to many factors, ranging from the complexity of the ghrelin receptor (Growth Hormone Secretagogue Receptor, GHSR-1a) internalisation and heterodimerization, to biased ligand interactions and compensatory neuroendocrine outputs. Not least is the ubiquitous expression of the GHSR-1a, which makes it impossible to modulate centrally-mediated appetite regulation without encroaching on the various peripheral functions attributable to ghrelin. It is becoming clear that ghrelin’s central signalling is critical for its effects on appetite, body weight regulation and incentive salience of food. Improving the ability of ghrelin ligands to penetrate the blood brain barrier would enhance central delivery to GHSR-1a expressing brain regions, particularly within the mesolimbic reward circuitry.
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30
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Özcan B, Leenen PJM, Delhanty PJD, Baldéon-Rojas LY, Neggers SJ, van der Lely AJ. Unacylated ghrelin modulates circulating angiogenic cell number in insulin-resistant states. Diabetol Metab Syndr 2017; 9:43. [PMID: 28572856 PMCID: PMC5452348 DOI: 10.1186/s13098-017-0239-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 05/17/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Type 2 diabetes (T2D) is associated with reduced numbers and impaired function of circulating angiogenic cells (CAC) which contributes to the progression of atherosclerosis and microvascular disease. Previous studies suggest that short-term infusion of unacylated ghrelin (UAG) normalizes CAC number in patients with T2D. To determine dose-dependent effects of short-term infusion of UAG in T2D patients using a cross-over model, and of long-term infusion of UAG in obese mice, on differentiation of monocyte progenitors into CAC. METHODS Eight overweight T2D patients were infused overnight with 3 and 10 µg/kg/h of UAG in a double-blind, placebo-controlled cross-over study. To assess the effects of long-term UAG treatment, obese mice were infused with UAG for 4 weeks. Monocyte progenitors were assessed for their ability to differentiate into CAC in vitro. RESULTS In T2D patients, UAG treatment caused a reduction in differentiation of CAC, dependent on UAG dose and differentiation method. However, mice treated with UAG showed a significant increase in differentiation of bone marrow progenitors into CAC. CONCLUSION UAG causes a minor suppressive effect on CAC development after short-term treatment in humans, but experiments in mice suggest that long-term treatment has beneficial effects on CAC formation. The Netherlands Trial Register: TC=2487.
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Affiliation(s)
- Behiye Özcan
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
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31
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Unacylated ghrelin analog prevents myocardial reperfusion injury independently of permeability transition pore. Basic Res Cardiol 2016; 112:4. [PMID: 27995363 DOI: 10.1007/s00395-016-0595-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 12/09/2016] [Indexed: 02/06/2023]
Abstract
Reperfusion injury is responsible for an important part of myocardial infarct establishment due notably to triggering cardiomyocytes death at the first minutes of reperfusion. AZP-531 is an optimized analog of unacylated ghrelin currently in clinical development in several metabolic diseases. We investigated a potential cardioprotective effect of AZP-531 in ischemia/reperfusion (IR) and the molecular underlying mechanism(s) involved in this protection. In vivo postconditioning with AZP-531 in C57BL6 mouse IR model decreased infarct size. Western blot analysis on areas at risk from the different mouse groups showed that AZP-531 activates Akt, ERK1-2 as well as S6 and 4EBP1, mTORC1 effectors. We also showed an inhibition of caspase 3 cleavage and Bax translocation to the mitochondria. AZP-531 also stimulated the expression of antioxidants and was capable of decreasing mitochondrial H2O2 production, contributing to the reduction of ROS accumulation. AZP-531 exhibits cardioprotective effect when administrated for postconditioning in C57BL6 mouse IR model. Treatment with AZP-531 rescued the myocardium from cell death at early reperfusion by stimulating protein synthesis, inhibiting Bax/caspase 3-induced apoptosis as well as ROS accumulation and oxidative stress-induced necrosis. AZP-531 may prove useful in the treatment of IR injury.
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32
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Allas S, Delale T, Ngo N, Julien M, Sahakian P, Ritter J, Abribat T, van der Lely AJ. Safety, tolerability, pharmacokinetics and pharmacodynamics of AZP-531, a first-in-class analogue of unacylated ghrelin, in healthy and overweight/obese subjects and subjects with type 2 diabetes. Diabetes Obes Metab 2016; 18:868-74. [PMID: 27063928 DOI: 10.1111/dom.12675] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 04/05/2016] [Accepted: 02/24/2016] [Indexed: 01/05/2023]
Abstract
AIM To explore the safety, pharmacokinetics and pharmacodynamics in humans of the unacylated ghrelin analogue AZP-531, designed to improve glycaemic control and reduce weight. METHODS Assessments, including glucose measurements, were performed in a three-part randomized study. In Part A, healthy subjects [n = 44, age 18-50 years, body mass index (BMI) 20-28 kg/m(2) ] received a single subcutaneous dose of 0.3, 3, 15, 30, 60 or 120 µg/kg AZP-531 or placebo. In Part B, overweight/obese subjects (n = 32, age 18-65 years, BMI 28-38 kg/m(2) ) and in Part C, patients with type 2 diabetes [T2D; n = 36, age 18-65 years, BMI 20-40 kg/m(2) , glycated haemoglobin (HbA1c) 7-10%] received AZP-531 or placebo for 14 days (daily doses of 3, 15, 30 or 60 µg/kg and 15, 2 × 30 or 60 µg/kg, respectively). RESULTS AZP-531 was well tolerated. Single- and multiple-dose pharmokinetic variables were similar. Maximum AZP-531 concentrations were typically reached at 1 h post-dose. Observed maximum concentration (Cmax ) and area under the curve were dose-proportional. The mean terminal half-life (t1/2 ) was 2-3 h. In Part B, AZP-531 doses of ≥15 µg/kg significantly improved glucose concentrations, without increasing insulin levels, suggesting an insulin-sensitizing effect. AZP-531 decreased mean body weight by 2.6 kg (vs 0.8 kg for placebo). In Part C, glucose variables improved in all groups, including placebo, suggesting a study effect in uncontrolled patients at baseline. Notwithstanding, AZP-531 60 µg/kg reduced HbA1c by 0.4% (vs 0.2% for placebo) and body weight by 2.1 kg (vs 1.3 kg for placebo). CONCLUSIONS AZP-531 was well tolerated in this first-in-human study. Its pharmacokinetic profile, suitable for once-daily dosing, and metabolic effects support further clinical development for T2D.
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Affiliation(s)
- S Allas
- Alizé Pharma, Ecully, France
| | | | - N Ngo
- Quintiles Early Clinical Development PK Department, Overland Park, KS, USA
| | | | | | - J Ritter
- Phase 1 Quintiles Unit, London, UK
| | | | - A J van der Lely
- Department of Medicine, Erasmus University Medical Centre, Rotterdam, The Netherlands
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33
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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.
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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.
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Nowak N, Hohendorff J, Solecka I, Szopa M, Skupien J, Kiec-Wilk B, Mlynarski W, Malecki MT. Circulating ghrelin level is higher in HNF1A-MODY and GCK-MODY than in polygenic forms of diabetes mellitus. Endocrine 2015; 50:643-9. [PMID: 25987348 PMCID: PMC4662709 DOI: 10.1007/s12020-015-0627-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 05/05/2015] [Indexed: 02/07/2023]
Abstract
Ghrelin is a hormone that regulates appetite. It is likely to be involved in the pathophysiology of varying forms of diabetes. In animal studies, the ghrelin expression was regulated by the hepatocyte nuclear factor 1 alpha (HNF1A). Mutations of the HNF1A gene cause maturity onset diabetes of the young (MODY). We aimed to assess the circulating ghrelin levels in HNF1A-MODY and in other types of diabetes and to evaluate its association with HNF1A mutation status. Our cohort included 46 diabetic HNF1A gene mutation carriers, 55 type 2 diabetes (T2DM) subjects, 42 type 1 diabetes (T1DM) patients, and 31 glucokinase (GCK) gene mutation carriers with diabetes as well as 51 healthy controls. Plasma ghrelin concentration was measured using the immunoenzymatic assay with polyclonal antibody against the C-terminal fragment of its acylated and desacylated forms. Ghrelin concentrations were 0.75 ± 0.32, 0.70 ± 0.21, 0.50 ± 0.20, and 0.40 ± 0.16 ng/ml in patients with HNF1A-MODY, GCK-MODY, T1DM, and T2DM, respectively. The ghrelin levels were higher in HNF1A-MODY and GCK-MODY than in T1DM and T2DM (p < 0.001 for all comparisons) but lower than in non-diabetic controls (1.02 ± 0.29 ng/ml, p < 0.001 for both comparisons). In the multivariate linear model, the differences between both MODY groups and common diabetes types remained significant. Analysis by a HNF1A mutation type indicated that ghrelin concentration is similar in patients with different types of sequence differences. Plasma ghrelin level is higher in HNF1A-MODY and GCK-MODY than in the common polygenic forms of diabetes.
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Affiliation(s)
- Natalia Nowak
- Department of Metabolic Diseases, Jagiellonian University Medical College, 15 Kopernika Street, 31-501, Krakow, Poland
- Section on Genetics and Epidemiology, Joslin Diabetes Center, Boston, MA, USA
| | - Jerzy Hohendorff
- Department of Metabolic Diseases, Jagiellonian University Medical College, 15 Kopernika Street, 31-501, Krakow, Poland
- University Hospital, Krakow, Poland
| | | | - Magdalena Szopa
- Department of Metabolic Diseases, Jagiellonian University Medical College, 15 Kopernika Street, 31-501, Krakow, Poland
- University Hospital, Krakow, Poland
| | - Jan Skupien
- Department of Metabolic Diseases, Jagiellonian University Medical College, 15 Kopernika Street, 31-501, Krakow, Poland
- University Hospital, Krakow, Poland
| | - Beata Kiec-Wilk
- Department of Metabolic Diseases, Jagiellonian University Medical College, 15 Kopernika Street, 31-501, Krakow, Poland
- University Hospital, Krakow, Poland
| | - Wojciech Mlynarski
- Department of Pediatrics, Oncology, Hematology and Diabetology, Medical University of Lodz, Lodz, Poland
| | - Maciej T Malecki
- Department of Metabolic Diseases, Jagiellonian University Medical College, 15 Kopernika Street, 31-501, Krakow, Poland.
- University Hospital, Krakow, Poland.
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Khatib MN, Gaidhane S, Gaidhane AM, Simkhada P, Zahiruddin QS. Ghrelin O Acyl Transferase (GOAT) as a Novel Metabolic Regulatory Enzyme. J Clin Diagn Res 2015; 9:LE01-5. [PMID: 25859472 PMCID: PMC4378754 DOI: 10.7860/jcdr/2015/9787.5514] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 12/06/2014] [Indexed: 01/12/2023]
Abstract
BACKGROUND Obesity and Type 2 Diabetes Mellitus (T2DM) presents a growing threat to the global health. Evidences highlight an important role of ghrelin as a key regulator of glucose metabolism. The physiological functions of ghrelin are mediated by enzyme ghrelin-O-acyltransferase (GOAT) which is capable of generating the active form of this metabolic hormone. However, its exact mechanism of action and influence on energy balance and glucose metabolism is yet to be explored. OBJECTIVES To review the physiological role of GOAT in the regulation of energy balance and glucose metabolism and explore the potential therapeutic avenues of modulators of GOAT to counter the progression of obesity and T2DM. METHODS Publications were sought through electronic searches. The bibliographies of all papers, book, chapters and editorials were scanned and hand searches were also conducted for journals, and conference proceedings. CONCLUSION GOAT peptide modulates the insulin secretion as well as insulin sensitivity. Modulators of GOAT signaling like inhibitors of GOAT increases insulin secretion, enhance peripheral insulin sensitivity and thus counters obesity and T2DM. Modulators of GOAT can be a probable therapy for modifying food intake and for countering obesity and T2DM.
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Affiliation(s)
- Mahalaqua Nazli Khatib
- Professor, Department of Physiology, JN Medical College, Datta Meghe Institute of Medical Sciences, Wardha, Maharashtra, India
| | - Shilpa Gaidhane
- Associate Professor, Department of Medicine, JN Medical College, Datta Meghe Institute of Medical Sciences, Wardha, Maharashtra, India
| | - Abhay M. Gaidhane
- Professor, Department of Community Medicine, JN Medical College, Datta Meghe Institute of Medical Sciences, Wardha, Maharashtra, India
| | - Padam Simkhada
- Senior Lecturer in International Health ScHARR, University of Sheffield, UK and Centre for public Health Liverpool Johns Moores University, Liverpool, UK
| | - Quazi Syed Zahiruddin
- Professor, Department of Community Medicine, JN Medical College, Datta Meghe Institute of Medical Sciences, Wardha, Maharashtra, India
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Angelino E, Reano S, Ferrara M, Agosti E, Graziani A, Filigheddu N. Antifibrotic activity of acylated and unacylated ghrelin. Int J Endocrinol 2015; 2015:385682. [PMID: 25960743 PMCID: PMC4415458 DOI: 10.1155/2015/385682] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 04/01/2015] [Indexed: 12/15/2022] Open
Abstract
Fibrosis can affect almost all tissues and organs, it often represents the terminal stage of chronic diseases, and it is regarded as a major health issue for which efficient therapies are needed. Tissue injury, by inducing necrosis/apoptosis, triggers inflammatory response that, in turn, promotes fibroblast activation and pathological deposition of extracellular matrix. Acylated and unacylated ghrelin are the main products of the ghrelin gene. The acylated form, through its receptor GHSR-1a, stimulates appetite and growth hormone (GH) release. Although unacylated ghrelin does not bind or activate GHSR-1a, it shares with the acylated form several biological activities. Ghrelin peptides exhibit anti-inflammatory, antioxidative, and antiapoptotic activities, suggesting that they might represent an efficient approach to prevent or reduce fibrosis. The aim of this review is to summarize the available evidence regarding the effects of acylated and unacylated ghrelin on different pathologies and experimental models in which fibrosis is a predominant characteristic.
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Affiliation(s)
- Elia Angelino
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
| | - Simone Reano
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
| | - Michele Ferrara
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
| | - Emanuela Agosti
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
| | - Andrea Graziani
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
| | - Nicoletta Filigheddu
- Department of Translational Medicine, University of Piemonte Orientale, Via Solaroli 17, 28100 Novara, Italy
- *Nicoletta Filigheddu:
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Delhanty PJD, Huisman M, Julien M, Mouchain K, Brune P, Themmen APN, Abribat T, van der Lely AJ. The acylated (AG) to unacylated (UAG) ghrelin ratio in esterase inhibitor-treated blood is higher than previously described. Clin Endocrinol (Oxf) 2015; 82:142-6. [PMID: 24810977 DOI: 10.1111/cen.12489] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/11/2014] [Accepted: 05/01/2014] [Indexed: 01/13/2023]
Abstract
CONTEXT The acylated/unacylated ghrelin (AG/UAG) ratio has been reported to range from 0·02 to 0·3, suggesting biologically relevant independent regulation of each ghrelin isoform. However, AG is deacylated to UAG by esterases in blood samples, and esterase inhibition is critical for their accurate measurement. Our hypothesis is that at least part of the variation in reported AG and UAG values is due to inconsistent sample preparation. DESIGN A non-interventional study. Quantification with two different, commercially available, ELISA formats of AG and UAG in venous plasma stabilized or not with 4-(2-aminoethyl) benzenesulphonyl fluoride (AEBSF) and stored for 0-6 months at -20 or -80 °C. PARTICIPANTS Healthy, non-obese, adults (n = 8; 4 women), age 26-42 yrs, after an overnight fast. MEASUREMENTS AG and UAG stability following different methods of sample treatment and storage. RESULTS Non-AEBSF plasma contained low AG and high UAG (>270 pg/ml) indicating rapid conversion of AG to UAG. However, AEBSF plasma, stored at -80 °C and measured at 0, 1, 3 and 6 months contained AG and UAG ranges of 12-350 and 17-170 pg/ml, respectively. Mean (SEM) AG/UAG ratios were 1·7(0·3), 1·2(0·2), 1·5(0·3) and 1·8(0·5) at each time point with no significant effect of storage period. CONCLUSIONS AG and UAG levels measured in AEBSF-stabilized plasma indicate that the AG/UAG ratio is markedly higher than previously described and that UAG is a physiological component of the circulation. This highlights the importance of immediately stabilizing blood samples on collection for determination of both AG and UAG concentrations and provides a valuable tool for their measurement in physiological and interventional studies.
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Ghrelin: a link between ageing, metabolism and neurodegenerative disorders. Neurobiol Dis 2014; 72 Pt A:72-83. [PMID: 25173805 DOI: 10.1016/j.nbd.2014.08.026] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 06/28/2014] [Accepted: 08/20/2014] [Indexed: 12/13/2022] Open
Abstract
Along with the increase in life expectancy over the last century comes the increased risk for development of age-related disorders, including metabolic and neurodegenerative diseases such as Alzheimer's, Parkinson's and Huntington's diseases. These chronic disorders share two main characteristics: 1) neuronal loss in motor, sensory or cognitive systems, leading to cognitive and motor decline; and 2) a strong correlation between metabolic changes and neurodegeneration. In order to treat them, a better understanding of their complexity is required: it is necessary to interpret the neuronal damage in light of the metabolic changes, and to find the disrupted link between the peripheral organs governing energy metabolism and the CNS. This review is an attempt to present ghrelin as part of molecular regulatory interface between energy metabolism, neuroendocrine and neurodegenerative processes. Ghrelin takes part in lipid and glucose metabolism, in higher brain functions such as sleep-wake state, learning and memory consolidation; it influences mitochondrial respiration and shows neuroprotective effect. All these make ghrelin an attractive target for development of biomarkers or therapeutics for prevention or treatment of disorders, in which cell protection and recruitment of new neurons or synapses are needed.
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Callaghan B, Furness JB. Novel and Conventional Receptors for Ghrelin, Desacyl-Ghrelin, and Pharmacologically Related Compounds. Pharmacol Rev 2014; 66:984-1001. [DOI: 10.1124/pr.113.008433] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Cameron KO, Bhattacharya SK, Loomis AK. Small Molecule Ghrelin Receptor Inverse Agonists and Antagonists. J Med Chem 2014; 57:8671-91. [DOI: 10.1021/jm5003183] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Kimberly O. Cameron
- Worldwide
Medicinal Chemistry, Pfizer Worldwide Research and Development, 610
Main Street, Cambridge, Massachusetts 02139, United States
| | - Samit K. Bhattacharya
- Worldwide
Medicinal Chemistry, Pfizer Worldwide Research and Development, 610
Main Street, Cambridge, Massachusetts 02139, United States
| | - A. Katrina Loomis
- Pharmatherapeutics
Precision Medicine, Pfizer Worldwide Research and Development, Eastern
Point Road, Groton, Connecticut 06340, United States
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Docanto MM, Yang F, Callaghan B, Au CC, Ragavan R, Wang X, Furness JB, Andrews ZB, Brown KA. Ghrelin and des-acyl ghrelin inhibit aromatase expression and activity in human adipose stromal cells: suppression of cAMP as a possible mechanism. Breast Cancer Res Treat 2014; 147:193-201. [PMID: 25056185 DOI: 10.1007/s10549-014-3060-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 07/10/2014] [Indexed: 01/10/2023]
Abstract
Aromatase converts androgens into estrogens and its expression within adipose stromal cells (ASCs) is believed to be the major driver of estrogen-dependent cancers in older women. Ghrelin is a gut-hormone that is involved in the regulation of appetite and known to bind to and activate the cognate ghrelin receptor, GHSR1a. The unacylated form of ghrelin, des-acyl ghrelin, binds weakly to GHSR1a but has been shown to play an important role in regulating a number of physiological processes. The aim of this study was to determine the effect of ghrelin and des-acyl ghrelin on aromatase in primary human ASCs. Primary human ASCs were isolated from adipose tissue of women undergoing cosmetic surgery. Real-time PCR and tritiated water-release assays were performed to examine the effect of treatment on aromatase transcript expression and aromatase activity, respectively. Treatments included ghrelin, des-acyl ghrelin, obestatin, and capromorelin (GHSR1a agonist). GHSR1a protein expression was assessed by Western blot and effects of treatment on Ca(2+) and cAMP second messenger systems were examined using the Flexstation assay and the Lance Ultra cAMP kit, respectively. Results demonstrate that pM concentrations of ghrelin and des-acyl ghrelin inhibit aromatase transcript expression and activity in ASCs under basal conditions and in PGE2-stimulated cells. Moreover, the effects of ghrelin and des-acyl ghrelin are mediated via effects on aromatase promoter PII-specific transcripts. Neither the GHSR1a-specific agonist capromorelin nor obestatin had any effect on aromatase transcript expression or activity. Moreover, GHSR1a protein was undetectable by Western blot and neither ghrelin nor capromorelin elicited a calcium response in ASCs. Finally, ghrelin caused a significant decrease in basal and forskolin-stimulated cAMP in ASC. These findings suggest that ghrelin acts at alternate receptors in ASCs by decreasing intracellular cAMP levels. Ghrelin mimetics may be useful in the treatment of estrogen-dependent breast cancer.
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Affiliation(s)
- Maria M Docanto
- Metabolism & Cancer Laboratory, MIMR-PHI Institute of Medical Research, Clayton, VIC, 3168, Australia
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Heppner KM, Tong J. Mechanisms in endocrinology: regulation of glucose metabolism by the ghrelin system: multiple players and multiple actions. Eur J Endocrinol 2014; 171:R21-32. [PMID: 24714083 DOI: 10.1530/eje-14-0183] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ghrelin is a 28-amino acid peptide secreted mainly from the X/A-like cells of the stomach. Ghrelin is found in circulation in both des-acyl (dAG) and acyl forms (AG). Acylation is catalyzed by the enzyme ghrelin O-acyltransferase (GOAT). AG acts on the GH secretagogue receptor (GHSR) in the CNS to promote feeding and adiposity and also acts on GHSR in the pancreas to inhibit glucose-stimulated insulin secretion. These well-described actions of AG have made it a popular target for obesity and type 2 diabetes mellitus pharmacotherapies. However, despite the lack of a cognate receptor, dAG appears to have gluco-regulatory action, which adds an additional layer of complexity to ghrelin's regulation of glucose metabolism. This review discusses the current literature on the gluco-regulatory action of the ghrelin system (dAG, AG, GHSR, and GOAT) with specific emphasis aimed toward distinguishing AG vs dAG action.
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Affiliation(s)
- Kristy M Heppner
- Division of DiabetesObesity and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon, USA andDivision of EndocrinologyDiabetes and Metabolism, Department of Medicine, University of Cincinnati, 260 Stetson Street, Suite 4200, Cincinnati, Ohio 45219-0547, USA
| | - Jenny Tong
- Division of DiabetesObesity and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon, USA andDivision of EndocrinologyDiabetes and Metabolism, Department of Medicine, University of Cincinnati, 260 Stetson Street, Suite 4200, Cincinnati, Ohio 45219-0547, USA
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Tong J, Davis HW, Summer S, Benoit SC, Haque A, Bidlingmaier M, Tschöp MH, D'Alessio D. Acute administration of unacylated ghrelin has no effect on Basal or stimulated insulin secretion in healthy humans. Diabetes 2014; 63:2309-19. [PMID: 24550190 PMCID: PMC4066344 DOI: 10.2337/db13-1598] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Unacylated ghrelin (UAG) is the predominant ghrelin isoform in the circulation. Despite its inability to activate the classical ghrelin receptor, preclinical studies suggest that UAG may promote β-cell function. We hypothesized that UAG would oppose the effects of acylated ghrelin (AG) on insulin secretion and glucose tolerance. AG (1 µg/kg/h), UAG (4 µg/kg/h), combined AG+UAG, or saline were infused to 17 healthy subjects (9 men and 8 women) on four occasions in randomized order. Ghrelin was infused for 30 min to achieve steady-state levels and continued through a 3-h intravenous glucose tolerance test. The acute insulin response to glucose (AIRg), insulin sensitivity index (SI), disposition index (DI), and intravenous glucose tolerance (kg) were compared for each subject during the four infusions. AG infusion raised fasting glucose levels but had no effect on fasting plasma insulin. Compared with the saline control, AG and AG+UAG both decreased AIRg, but UAG alone had no effect. SI did not differ among the treatments. AG, but not UAG, reduced DI and kg and increased plasma growth hormone. UAG did not alter growth hormone, cortisol, glucagon, or free fatty acid levels. UAG selectively decreased glucose and fructose consumption compared with the other treatments. In contrast to previous reports, acute administration of UAG does not have independent effects on glucose tolerance or β-cell function and neither augments nor antagonizes the effects of AG.
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Affiliation(s)
- Jenny Tong
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, OH
| | - Harold W Davis
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, OH
| | - Suzanne Summer
- Clinical Translational Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Stephen C Benoit
- Department of Psychiatry, University of Cincinnati, Cincinnati, OH
| | - Ahrar Haque
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, OH
| | - Martin Bidlingmaier
- Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität, Munich, Germany
| | - Matthias H Tschöp
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, OHInstitute for Obesity and Diabetes, Helmholtz Center Munich and Division of Metabolic Diseases, Department of Medicine, Technical University, Munich, Germany
| | - David D'Alessio
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, OHCincinnati Veterans Affairs Medical Center, Cincinnati, OH
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Affiliation(s)
- Rocco Barazzoni
- Internal Medicine, Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
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45
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Chabot F, Caron A, Laplante M, St-Pierre DH. Interrelationships between ghrelin, insulin and glucose homeostasis: Physiological relevance. World J Diabetes 2014; 5:328-341. [PMID: 24936254 PMCID: PMC4058737 DOI: 10.4239/wjd.v5.i3.328] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 05/08/2014] [Indexed: 02/05/2023] Open
Abstract
Ghrelin is a 28 amino acid peptide mainly derived from the oxyntic gland of the stomach. Both acylated (AG) and unacylated (UAG) forms of ghrelin are found in the circulation. Initially, AG was considered as the only bioactive form of ghrelin. However, recent advances indicate that both AG and UAG exert distinct and common effects in organisms. Soon after its discovery, ghrelin was shown to promote appetite and adiposity in animal and human models. In response to these anabolic effects, an impressive number of elements have suggested the influence of ghrelin on the regulation of metabolic functions and the development of obesity-related disorders. However, due to the complexity of its biochemical nature and the physiological processes it governs, some of the effects of ghrelin are still debated in the literature. Evidence suggests that ghrelin influences glucose homeostasis through the modulation of insulin secretion and insulin receptor signaling. On the other hand, insulin was also shown to influence circulating levels of ghrelin. Here, we review the relationship between ghrelin and insulin and we describe the impact of this interaction on the modulation of glucose homeostasis.
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Özcan B, Neggers SJCMM, Miller AR, Yang HC, Lucaites V, Abribat T, Allas S, Huisman M, Visser JA, Themmen APN, Sijbrands EJG, Delhanty PJD, van der Lely AJ. Does des-acyl ghrelin improve glycemic control in obese diabetic subjects by decreasing acylated ghrelin levels? Eur J Endocrinol 2014; 170:799-807. [PMID: 23864339 DOI: 10.1530/eje-13-0347] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE The objective of this study was to assess the effects of a continuous overnight infusion of des-acyl ghrelin (DAG) on acylated ghrelin (AG) levels and glucose and insulin responses to a standard breakfast meal (SBM) in eight overweight patients with type 2 diabetes. Furthermore, in the same patients and two additional subjects, the effects of DAG infusion on AG concentrations and insulin sensitivity during a hyperinsulinemic-euglycemic clamp (HEC) were assessed. RESEARCH DESIGN AND METHODS A double-blind, placebo-controlled cross-over study design was implemented, using overnight continuous infusions of 3 and 10 μg DAG/kg per h and placebo to study the effects on a SBM. During a HEC, we studied the insulin sensitivity. RESULTS We observed that, compared with placebo, overnight DAG administration significantly decreased postprandial glucose levels, both during continuous glucose monitoring and at peak serum glucose levels. The degree of improvement in glycemia was correlated with baseline plasma AG concentrations. Concurrently, DAG infusion significantly decreased fasting and postprandial AG levels. During the HEC, 2.5 h of DAG infusion markedly decreased AG levels, and the M-index, a measure of insulin sensitivity, was significantly improved in the six subjects in whom we were able to attain steady-state euglycemia. DAG administration was not accompanied by many side effects when compared with placebo. CONCLUSIONS DAG administration improves glycemic control in obese subjects with type 2 diabetes through the suppression of AG levels. DAG is a good candidate for the development of compounds in the treatment of metabolic disorders or other conditions with a disturbed AG:DAG ratio, such as type 2 diabetes mellitus or Prader-Willi syndrome.
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Affiliation(s)
- Behiye Özcan
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Sebastian J C M M Neggers
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Anne Reifel Miller
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Hsiu-Chiung Yang
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Virginia Lucaites
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Thierry Abribat
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Soraya Allas
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Martin Huisman
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Jenny A Visser
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Axel P N Themmen
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Eric J G Sijbrands
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Patric J D Delhanty
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
| | - Aart Jan van der Lely
- Department of Internal MedicineErasmus University Medical Centre, PO Box 2040, 3000 CA, Rotterdam, The NetherlandsLilly Research LaboratoriesLilly Corporate Center, Indianapolis, Indiana 46285, USAAlizé Pharma69 130 Ecully, France
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Arellanes-Licea EDC, Báez-Ruiz A, Carranza ME, Arámburo C, Luna M, Díaz-Muñoz M. Daily patterns and adaptation of the ghrelin, growth hormone and insulin-like growth factor-1 system under daytime food synchronisation in rats. J Neuroendocrinol 2014; 26:282-95. [PMID: 24617825 DOI: 10.1111/jne.12145] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 02/07/2014] [Accepted: 03/06/2014] [Indexed: 11/29/2022]
Abstract
Daytime restricted feeding promotes the re-alignment of the food entrained oscillator (FEO). Endocrine cues which secretion is regulated by the transition of fasting and feeding cycles converge in the FEO. The present study aimed to investigate the ghrelin, growth hormone (GH) and insulin-like growth factor (IGF)-1 system because their release depends on rhythmic and nutritional factors, and the output from the system influences feeding and biochemical status. In a daily sampling approach, rats that were fed ad lib. were compared with rats on a reversed (daytime) and restricted feeding schedule by 3 weeks (dRF; food access for 2 h), also assessing the effect of acute fasting and refeeding. We undertook measurements of clock protein BMAL1 and performed somatometry of peripheral organs and determined the concentration of total, acylated and unacylated ghrelin, GH and IGF-1 in both serum and in its main synthesising organs. During dRF, BMAL1 expression was synchronised to mealtime in hypophysis and liver; rats exhibited acute hyperphagia, stomach distension with a slow emptying, a phase shift in liver mass towards the dark period and decrease in mass perigonadal white adipose tissue. Total ghrelin secretion during the 24-h period increased in the dRF group as a result of elevation of the unacylated form. By contrast, GH and IGF-1 serum concentration fell, with a modification of GH daily pattern after mealtime. In the dRF group, ghrelin content in the stomach and pituitary GH content decreased, whereas hepatic IGF-1 remained equal. The daily patterns and synthesis of these hormones had a rheostatic adaptation. The endocrine adaptive response elicited suggests that it may be associated with the regulation of metabolic, behavioural and physiological processes during the paradigm of daytime restricted feeding and associated FEO activity.
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Affiliation(s)
- E del C Arellanes-Licea
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, México
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Prodam F, Filigheddu N. Ghrelin gene products in acute and chronic inflammation. Arch Immunol Ther Exp (Warsz) 2014; 62:369-84. [PMID: 24728531 DOI: 10.1007/s00005-014-0287-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 03/21/2014] [Indexed: 12/27/2022]
Abstract
Ghrelin gene products--the peptides ghrelin, unacylated ghrelin, and obestatin--have several actions on the immune system, opening new perspectives within neuroendocrinology, metabolism and inflammation. The aim of this review is to summarize the available evidence regarding the less known role of these peptides in the machinery of inflammation and autoimmunity, outlining some of their most promising therapeutic applications.
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Affiliation(s)
- Flavia Prodam
- Departmant of Health Sciences, Università del Piemonte Orientale "Amedeo Avogadro", Novara, Italy
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Shimada T, Furuta H, Doi A, Ariyasu H, Kawashima H, Wakasaki H, Nishi M, Sasaki H, Akamizu T. Des-acyl ghrelin protects microvascular endothelial cells from oxidative stress-induced apoptosis through sirtuin 1 signaling pathway. Metabolism 2014; 63:469-74. [PMID: 24486147 DOI: 10.1016/j.metabol.2013.12.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 12/19/2013] [Accepted: 12/21/2013] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Ghrelin is a stomach-derived hormone. Acylation of ghrelin has been essential for its biological activities such as stimulating appetite. On the other hand, the function of des-acyl ghrelin (Des-G) has not been fully elucidated. The aim of the present study is to examine the anti-apoptotic effect of Des-G on endothelial cells. MATERIALS/METHODS After human retinal microvascular endothelial cells (RMECs) were pretreated with or without 100nmol/L Des-G, apoptosis was induced with 0.1mmol/L hydrogen peroxide (H2O2). For pharmacological inhibition of surtuin 1 (SIRT1) catalytic activity, the cells were treated with 10μmol/L Ex-527. Inhibition of SIRT1 with siRNA was also performed. The quantitative estimation of DNA fragmentation was used as a marker of apoptosis. Furthermore, total SIRT activity in nuclear extracts, mRNA and protein levels of SIRT1, manganese superoxide dismutase (MnSOD) and catalase were determined. RESULTS Des-G pretreatment protected RMECs from oxidative stress-induced apoptosis and increased SIRTs deacetylase activity in nuclear extracts. On the other hand, both pharmacological and siRNA mediated inhibition of SIRT1 attenuated the anti-apoptotic effect of Des-G. Moreover, Des-G increased mRNA and protein levels of SIRT1 and antioxidant enzymes such as MnSOD and CAT, which are downstream targets of SIRT1. Although the treatment of Ex-527 did not alter mRNA expression levels of SIRT1, it decreased mRNA expression levels of antioxidant enzymes in the cells with Des-G pretreatment. CONCLUSIONS Our results suggest that SIRT1 signaling pathway contributes to protective effect of Des-G against oxidative stress-induced apoptosis.
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Affiliation(s)
- Takeshi Shimada
- The First Department of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Hiroto Furuta
- The First Department of Medicine, Wakayama Medical University, Wakayama, Japan.
| | - Asako Doi
- The First Department of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Hiroyuki Ariyasu
- The First Department of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Hiromichi Kawashima
- The First Department of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Hisao Wakasaki
- The First Department of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Masahiro Nishi
- The First Department of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Hideyuki Sasaki
- The First Department of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Takashi Akamizu
- The First Department of Medicine, Wakayama Medical University, Wakayama, Japan
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Rodríguez A. Novel molecular aspects of ghrelin and leptin in the control of adipobiology and the cardiovascular system. Obes Facts 2014; 7:82-95. [PMID: 24685565 PMCID: PMC5644879 DOI: 10.1159/000360837] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 11/15/2013] [Indexed: 01/27/2023] Open
Abstract
Ghrelin and leptin show opposite effects on energy balance. Ghrelin constitutes a gut hormone that is secreted to the bloodstream in two major forms, acylated and desacyl ghrelin. The isoforms of ghrelin not only promote adiposity by the activation of hypothalamic orexigenic neurons but also directly stimulate the expression of several fat storage-related proteins in adipocytes, including ACC, FAS, LPL and perilipin, thereby stimulating intracytoplasmic lipid accumulation. Moreover, both acylated and desacyl ghrelin reduce TNF-α-induced apoptosis and autophagy in adipocytes, suggesting an anti-inflammatory role of ghrelin in human adipose tissue. On the other hand, leptin is an adipokine with lipolytic effects. In this sense, leptin modulates via PI3K/Akt/mTOR the expression of aquaglyceroporins such as AQP3 and AQP7 that facilitate glycerol efflux from adipocytes in response to the lipolytic stimuli via its translocation from the cytosolic fraction (AQP3) or lipid droplets (AQP7) to the plasma membrane. Ghrelin and leptin also participate in the homeostasis of the cardiovascular system. Ghrelin operates as a cardioprotective factor with increased circulating acylated ghrelin concentrations in patients with left ventricular hypertrophy (LVH) causally related to LV remodeling during the progression to LVH. Additionally, leptin induces vasodilation by inducible NO synthase expression (iNOS) in the vascular wall. In this sense, leptin inhibits the angiotensin II-induced Ca(2+) increase, contraction and proliferation of VSMC through NO-dependent mechanisms. Together, dysregulation of circulating ghrelin isoforms and leptin resistance associated to obesity, type 2 diabetes, or the metabolic syndrome contribute to cardiometabolic derangements observed in these pathologies.
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Affiliation(s)
- Amaia Rodríguez
- Metabolic Research Laboratory, Clínica Universidad de Navarra, Pamplona
- CIBER Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Spain
- *Amaia Rodrèguez, PhD, Metabolic Research Laboratory, Clínica Universidad de Navarra, Irunlarrea 1, 31008 Pamplona (Spain),
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